This document discusses power transmission through rotating machines. It defines different types of rotating machines including driving machines, transmission machines, and driven machines. It then focuses on the three major systems for transmitting rotary motion between adjacent shafts: belts, chains, and gears. The document provides detailed information on belt drives, including the four main types of belts and principles of V-belt operation. It also discusses synchronous belts, chain drives, and compares key aspects of belt drives and chain drives.
Program and Schedule of Preventive Maintenance in Mechanical EquipmentPavithraSuchindran
The document discusses the program and schedule for preventive maintenance of mechanical equipment. It covers various mechanical parts like bearings, gears, shafts and their maintenance. Plain bearings, rolling-element bearings, flexible couplings, chains, cranes, hoists, belt drives, gear drives and compressors are described along with their parts and recommended maintenance practices. The importance of proper lubrication, cleaning, inspection and replacement of worn parts is emphasized.
This document discusses mechanical drives and transmissions used for textile process machines. It covers various components used such as shafts, axles, spindles, keys, couplings, belts, chains, gears and gearboxes. It provides details on the types of each component, governing equations, material selection, inspection methods, common failures and maintenance practices. The document is an informative reference for the mechanical components used to transmit power in textile machinery.
1. Gear drives are mechanical systems that use gears to transmit power from one shaft to another. They provide advantages like transmitting large power, high efficiency, and reliability.
2. Gears can be classified based on the position of their shafts. Common types are spur gears, helical gears, bevel gears, worm gears, and planetary/epicyclic gears.
3. Epicyclic gear trains allow the axes of gears to move relative to a fixed axis. This allows high velocity ratios to be achieved with moderate sized gears in a small space. They are used in applications like lathes, differentials, hoists, and watches.
The document discusses various types of power transmission devices used to transfer motion and power between rotating shafts, including belt drives, chain drives, and gear drives. Belt drives can be flat, V-belt, timing or circular belts and are used to connect shafts over long distances. Chain drives use sprocket wheels connected by roller or silent chains. Gear drives include spur gears, helical gears, bevel gears, and worm gears to connect parallel, intersecting, or perpendicular shaft axes. Couplings like sleeve, split, flange, bush pin, and universal joints are also discussed for connecting shafts while allowing some misalignment or movement.
This document provides an overview of mechanical drives and power transmission maintenance. It discusses various types of drives including gear drives, belt drives, v-belt drives, chain drives, and discusses maintenance of sprockets and roller chains. The document provides information on components, operating principles, installation, alignment and preventative maintenance of these various mechanical drive systems.
I want this job to utilize the skills which I've gotten from my Boss, colleague and others. I will utilize this knowledge for the success of you and for my personal success. I will prove myself by my job.
This document provides an overview of rolling-contact bearings. It defines key terms like bearing life, load ratings, and reliability. It describes different types of ball and roller bearings and their applications. Formulas are presented for relating bearing load, life, and reliability based on catalog data. Methods for selecting bearings under combined radial and thrust loading conditions are also discussed.
The document discusses gear drive systems, specifically focusing on fundamental gear operation and maintenance. It covers why gears are used for power transmission, the basics of how gears transmit motion through conjugate action, common gear tooth profiles like involute and cycloidal curves, and considerations for gear design and lubrication. Involute tooth profiles are most widely used due to advantages like simple manufacturing, ability to transmit motion at varying center distances, and constant pressure angle providing smooth operation. Proper lubrication and avoiding interference or undercutting are important for gear performance and lifespan.
Program and Schedule of Preventive Maintenance in Mechanical EquipmentPavithraSuchindran
The document discusses the program and schedule for preventive maintenance of mechanical equipment. It covers various mechanical parts like bearings, gears, shafts and their maintenance. Plain bearings, rolling-element bearings, flexible couplings, chains, cranes, hoists, belt drives, gear drives and compressors are described along with their parts and recommended maintenance practices. The importance of proper lubrication, cleaning, inspection and replacement of worn parts is emphasized.
This document discusses mechanical drives and transmissions used for textile process machines. It covers various components used such as shafts, axles, spindles, keys, couplings, belts, chains, gears and gearboxes. It provides details on the types of each component, governing equations, material selection, inspection methods, common failures and maintenance practices. The document is an informative reference for the mechanical components used to transmit power in textile machinery.
1. Gear drives are mechanical systems that use gears to transmit power from one shaft to another. They provide advantages like transmitting large power, high efficiency, and reliability.
2. Gears can be classified based on the position of their shafts. Common types are spur gears, helical gears, bevel gears, worm gears, and planetary/epicyclic gears.
3. Epicyclic gear trains allow the axes of gears to move relative to a fixed axis. This allows high velocity ratios to be achieved with moderate sized gears in a small space. They are used in applications like lathes, differentials, hoists, and watches.
The document discusses various types of power transmission devices used to transfer motion and power between rotating shafts, including belt drives, chain drives, and gear drives. Belt drives can be flat, V-belt, timing or circular belts and are used to connect shafts over long distances. Chain drives use sprocket wheels connected by roller or silent chains. Gear drives include spur gears, helical gears, bevel gears, and worm gears to connect parallel, intersecting, or perpendicular shaft axes. Couplings like sleeve, split, flange, bush pin, and universal joints are also discussed for connecting shafts while allowing some misalignment or movement.
This document provides an overview of mechanical drives and power transmission maintenance. It discusses various types of drives including gear drives, belt drives, v-belt drives, chain drives, and discusses maintenance of sprockets and roller chains. The document provides information on components, operating principles, installation, alignment and preventative maintenance of these various mechanical drive systems.
I want this job to utilize the skills which I've gotten from my Boss, colleague and others. I will utilize this knowledge for the success of you and for my personal success. I will prove myself by my job.
This document provides an overview of rolling-contact bearings. It defines key terms like bearing life, load ratings, and reliability. It describes different types of ball and roller bearings and their applications. Formulas are presented for relating bearing load, life, and reliability based on catalog data. Methods for selecting bearings under combined radial and thrust loading conditions are also discussed.
The document discusses gear drive systems, specifically focusing on fundamental gear operation and maintenance. It covers why gears are used for power transmission, the basics of how gears transmit motion through conjugate action, common gear tooth profiles like involute and cycloidal curves, and considerations for gear design and lubrication. Involute tooth profiles are most widely used due to advantages like simple manufacturing, ability to transmit motion at varying center distances, and constant pressure angle providing smooth operation. Proper lubrication and avoiding interference or undercutting are important for gear performance and lifespan.
This document discusses the design of a rack and pinion gear system for a railway crossing gate. It outlines the objectives, need, and basic mechanism of a rack and pinion gear. The design methodology is explained, including design considerations, calculations, and material selection. Equations for determining forces on gear teeth, surface speed, strength, and wear are provided. Finally, the document summarizes the preliminary design of the pinion gear and next steps to design the rack.
The document discusses various power transmission systems used in industrial robotics including gears, belts, chains, shafts, and motion conversion mechanisms. Gears can be classified as external/internal or spur/helical/bevel/worm and are used to transmit motion between shafts. Belts and chains are also used for power transmission over longer distances. Motion conversion systems like lead screws, rack and pinion, and cam mechanisms are used to convert between rotary and linear motion.
The document discusses timing belt and auxiliary drive systems used in modern automotive engines. It provides an overview of timing belt and chain systems, explaining the components and operation of manual and automatic timing belt tensioners. It also discusses the multi-V belt used to drive multiple engine accessories and the importance of the cooling system, specifically the water pump. The document focuses on technology and material changes that have increased the performance and lifespan of modern timing belt and auxiliary drive components.
The document discusses different types of clutches used in vehicles, including their purpose and design. It describes jaw clutches, friction clutches, and their components like the flywheel, pressure plate, clutch plate, and release bearing. It also covers the operation of single and multi-plate clutches, their materials, and methods for analyzing clutch performance parameters like transmitted torque and temperature rise.
It is power point presentation on belt and chain drive. you can find working and mechanism of chain and belt drive and their advantage and disadvantages.....enjoy.
Power Transmission Devices: Construction, working, comparison, applications and classification of: Belt Drive (Flat and V Belt), Chain Drive and Spur Gear Drive arranged with simple gear trains
This document describes the design of a worm and worm wheel gear set. It begins with an introduction to worm gears and their applications where fast braking, low noise, or space constraints are important factors. The document then outlines the design process, which involves selecting design parameters like tooth count and lead angle, calculating loads, strength, and efficiency. The design problem provided is to transmit 22 kW between shafts 225 mm apart with a 24:1 transmission ratio using phosphor bronze materials. The document details the step-by-step design process to solve this problem and size the worm and worm wheel gears.
This document discusses different types of springs and their applications. It provides information on helical springs, leaf springs, disc springs, and helical spring design. The key points are:
- Springs store and release energy through elastic deformation, returning to their original shape after loading. Common applications include automobiles, trains, valves, and watches.
- Helical springs can be open or closed coil and are made of wire wound in a helix. Leaf springs use flat plates layered together. Disc springs use stacked discs.
- Springs cushion impacts, absorb/store energy, apply/control forces and motions. Helical spring design considers factors like wire diameter, coil diameter, and number of coils.
-
Introduction of Spur Gear theory by_Prof. Sagar DhotareSagar Dhotare
This PPT contains in formation of spur gear classification, Selection Parameters, Conditions, Tooth profile and System, Materials and Design consideration, Modes of failures
(1) Belts and chains are flexible power transmission elements that operate on pulleys or sprockets respectively. Belts can be flat, cogged, or V-shaped while chains are made of linked pins and operate on toothed wheels.
(2) When designing belt or chain drives, key parameters include the power rating, speed ratio, center distance, sheave/sprocket sizes, and wrap angle. The proper belt or chain type is selected based on the power and speed requirements.
(3) Examples show the step-by-step process for selecting belt sizes, determining sheave diameters and center distance, and ensuring adequate wrap angles. For chains, the sprocket tooth counts and sizes and center
Cam and follower theory prof. sagar a dhotareSagar Dhotare
This ppt covers following points,
Classification of Cam and Follower
Terminology of cam
Importance of Pressure angle
Application of Cam and Follower
Importance of cam and follower
Chain drive is a method of transmitting mechanical power from one place to another, often used to power vehicle wheels. It works by using a roller chain that passes over sprocket gears, with the gears' teeth meshing with the chain's links. Chains are classified into hoisting, conveyor, and power transmission chains. Power transmission chains are used in vehicles and machinery to convey power efficiently with little slippage between connected components. Chain drives require accurate installation and lubrication to function properly but can transmit power over variable distances compactly and with high efficiency.
B.tech i eme u 5 transmission of motion and powerRai University
This document provides information on various power transmission elements and methods of drive, including belts, chains, gears, shafts, and other components. It discusses the components and functioning of belt drives, including different types of belts. Chain drives are described as using sprockets and links to transmit power without slip. The different types of gears are outlined, including spur gears, helical gears, bevel gears, worm gears, and rack and pinion systems. Terminology related to gears such as pitch circle, pressure angle, and modules are also defined. The document aims to explain the basic components and principles of different power transmission methods.
Rolling Contact Bearing, Selection of Rolling Contact Bearings, Machine Element Design, Bantalan Gelinding, Pemilihan Bantalan Gelinding, Perancangan Elemen Mesin
This document discusses machine elements and power transmission devices used in mechanical engineering. It describes common machine elements like shafts, axles, keys, couplings, bearings, clutches, and brakes. It provides details on their functions, types, materials, and uses. Power transmission devices covered include belt drives, chain drives, and gear drives. Shafts are classified as machine shafts and transmission shafts. Different types of shafts and keys are defined along with their applications in power transmission.
Chain drives are commonly used to transmit mechanical power from one place to another using a roller chain and sprocket gears. The sprocket teeth mesh with the links of the chain to pull the chain and transfer mechanical force. Chain drives are compact and can transfer a large amount of torque. They are used in various industries to move materials by attaching objects directly to the chains or indirectly using rollers. Chain drives have advantages like not slipping, operating at high temperatures, and withstanding abrasive conditions, but require precise alignment and frequent lubrication.
This document discusses the calculation of bearing life and dynamic load ratings. It provides formulas and factors for calculating the radial and axial forces on bearings based on machine design and operating conditions. It also summarizes the Lundberg-Palmgren and SKF equations for calculating an equivalent dynamic bearing load and adjusted rating life of a bearing based on operating load and speed.
This document contains an assignment for a plant maintenance course. The 24-question assignment covers topics related to power transmission systems, including various drive components like belts, chains, gears, couplings and gearboxes. Students are asked to identify parts, define terms, calculate speeds, torques and other values, compare different drive types, and recommend solutions for various machine design scenarios. The assignment aims to test the student's understanding of key concepts and components in mechanical power transmission.
This document discusses power transmission using belt drives. It begins by introducing belt drives as a system used to transmit power from one mechanical element to another. The main types of belt drives are then described, including flat belts, V-belts, and circular belts. Key terms used in belt drives like driver, driven, tight side, and slack side are also defined. The document then discusses factors for selecting a belt drive system and provides examples of belt drives in various machines. It also covers velocity ratio calculations, slippage calculations, and examples problems determining pulley sizes for required speeds.
This document discusses the design of a rack and pinion gear system for a railway crossing gate. It outlines the objectives, need, and basic mechanism of a rack and pinion gear. The design methodology is explained, including design considerations, calculations, and material selection. Equations for determining forces on gear teeth, surface speed, strength, and wear are provided. Finally, the document summarizes the preliminary design of the pinion gear and next steps to design the rack.
The document discusses various power transmission systems used in industrial robotics including gears, belts, chains, shafts, and motion conversion mechanisms. Gears can be classified as external/internal or spur/helical/bevel/worm and are used to transmit motion between shafts. Belts and chains are also used for power transmission over longer distances. Motion conversion systems like lead screws, rack and pinion, and cam mechanisms are used to convert between rotary and linear motion.
The document discusses timing belt and auxiliary drive systems used in modern automotive engines. It provides an overview of timing belt and chain systems, explaining the components and operation of manual and automatic timing belt tensioners. It also discusses the multi-V belt used to drive multiple engine accessories and the importance of the cooling system, specifically the water pump. The document focuses on technology and material changes that have increased the performance and lifespan of modern timing belt and auxiliary drive components.
The document discusses different types of clutches used in vehicles, including their purpose and design. It describes jaw clutches, friction clutches, and their components like the flywheel, pressure plate, clutch plate, and release bearing. It also covers the operation of single and multi-plate clutches, their materials, and methods for analyzing clutch performance parameters like transmitted torque and temperature rise.
It is power point presentation on belt and chain drive. you can find working and mechanism of chain and belt drive and their advantage and disadvantages.....enjoy.
Power Transmission Devices: Construction, working, comparison, applications and classification of: Belt Drive (Flat and V Belt), Chain Drive and Spur Gear Drive arranged with simple gear trains
This document describes the design of a worm and worm wheel gear set. It begins with an introduction to worm gears and their applications where fast braking, low noise, or space constraints are important factors. The document then outlines the design process, which involves selecting design parameters like tooth count and lead angle, calculating loads, strength, and efficiency. The design problem provided is to transmit 22 kW between shafts 225 mm apart with a 24:1 transmission ratio using phosphor bronze materials. The document details the step-by-step design process to solve this problem and size the worm and worm wheel gears.
This document discusses different types of springs and their applications. It provides information on helical springs, leaf springs, disc springs, and helical spring design. The key points are:
- Springs store and release energy through elastic deformation, returning to their original shape after loading. Common applications include automobiles, trains, valves, and watches.
- Helical springs can be open or closed coil and are made of wire wound in a helix. Leaf springs use flat plates layered together. Disc springs use stacked discs.
- Springs cushion impacts, absorb/store energy, apply/control forces and motions. Helical spring design considers factors like wire diameter, coil diameter, and number of coils.
-
Introduction of Spur Gear theory by_Prof. Sagar DhotareSagar Dhotare
This PPT contains in formation of spur gear classification, Selection Parameters, Conditions, Tooth profile and System, Materials and Design consideration, Modes of failures
(1) Belts and chains are flexible power transmission elements that operate on pulleys or sprockets respectively. Belts can be flat, cogged, or V-shaped while chains are made of linked pins and operate on toothed wheels.
(2) When designing belt or chain drives, key parameters include the power rating, speed ratio, center distance, sheave/sprocket sizes, and wrap angle. The proper belt or chain type is selected based on the power and speed requirements.
(3) Examples show the step-by-step process for selecting belt sizes, determining sheave diameters and center distance, and ensuring adequate wrap angles. For chains, the sprocket tooth counts and sizes and center
Cam and follower theory prof. sagar a dhotareSagar Dhotare
This ppt covers following points,
Classification of Cam and Follower
Terminology of cam
Importance of Pressure angle
Application of Cam and Follower
Importance of cam and follower
Chain drive is a method of transmitting mechanical power from one place to another, often used to power vehicle wheels. It works by using a roller chain that passes over sprocket gears, with the gears' teeth meshing with the chain's links. Chains are classified into hoisting, conveyor, and power transmission chains. Power transmission chains are used in vehicles and machinery to convey power efficiently with little slippage between connected components. Chain drives require accurate installation and lubrication to function properly but can transmit power over variable distances compactly and with high efficiency.
B.tech i eme u 5 transmission of motion and powerRai University
This document provides information on various power transmission elements and methods of drive, including belts, chains, gears, shafts, and other components. It discusses the components and functioning of belt drives, including different types of belts. Chain drives are described as using sprockets and links to transmit power without slip. The different types of gears are outlined, including spur gears, helical gears, bevel gears, worm gears, and rack and pinion systems. Terminology related to gears such as pitch circle, pressure angle, and modules are also defined. The document aims to explain the basic components and principles of different power transmission methods.
Rolling Contact Bearing, Selection of Rolling Contact Bearings, Machine Element Design, Bantalan Gelinding, Pemilihan Bantalan Gelinding, Perancangan Elemen Mesin
This document discusses machine elements and power transmission devices used in mechanical engineering. It describes common machine elements like shafts, axles, keys, couplings, bearings, clutches, and brakes. It provides details on their functions, types, materials, and uses. Power transmission devices covered include belt drives, chain drives, and gear drives. Shafts are classified as machine shafts and transmission shafts. Different types of shafts and keys are defined along with their applications in power transmission.
Chain drives are commonly used to transmit mechanical power from one place to another using a roller chain and sprocket gears. The sprocket teeth mesh with the links of the chain to pull the chain and transfer mechanical force. Chain drives are compact and can transfer a large amount of torque. They are used in various industries to move materials by attaching objects directly to the chains or indirectly using rollers. Chain drives have advantages like not slipping, operating at high temperatures, and withstanding abrasive conditions, but require precise alignment and frequent lubrication.
This document discusses the calculation of bearing life and dynamic load ratings. It provides formulas and factors for calculating the radial and axial forces on bearings based on machine design and operating conditions. It also summarizes the Lundberg-Palmgren and SKF equations for calculating an equivalent dynamic bearing load and adjusted rating life of a bearing based on operating load and speed.
This document contains an assignment for a plant maintenance course. The 24-question assignment covers topics related to power transmission systems, including various drive components like belts, chains, gears, couplings and gearboxes. Students are asked to identify parts, define terms, calculate speeds, torques and other values, compare different drive types, and recommend solutions for various machine design scenarios. The assignment aims to test the student's understanding of key concepts and components in mechanical power transmission.
This document discusses power transmission using belt drives. It begins by introducing belt drives as a system used to transmit power from one mechanical element to another. The main types of belt drives are then described, including flat belts, V-belts, and circular belts. Key terms used in belt drives like driver, driven, tight side, and slack side are also defined. The document then discusses factors for selecting a belt drive system and provides examples of belt drives in various machines. It also covers velocity ratio calculations, slippage calculations, and examples problems determining pulley sizes for required speeds.
Shaft design2 Erdi Karaçal Mechanical Engineer University of GaziantepErdi Karaçal
The document discusses shaft design and analysis. It provides information on forces acting on shafts, developing shear and moment diagrams, stress concentration factors, fatigue failure criteria, and the ANSI shaft design equation. An example is presented to demonstrate calculating torque and forces on a shaft, developing shear and moment diagrams, and determining the shaft diameter at critical locations using the design equation.
The department aims to provide world-class mechanical engineering education through quality teaching that stimulates creativity and intellectual curiosity. It has highly qualified faculty across all mechanical engineering disciplines. The department has modern, well-furnished labs and workshops along with necessary design software to provide hands-on learning experiences. It aims to produce engineers who can work in diverse roles across many industries.
This document provides an introduction to machine elements and power transmission devices taught in the second semester of a mechanical engineering course. It discusses various machine elements like shafts, keys, couplings, bearings, clutches, and brakes. It also covers power transmission devices such as belt drives, chain drives, and gear drives. The document describes the function, types, materials, and design of these common mechanical components.
Vibration analysis of lathe structrure due to gear defect using fem 02THANMAY JS
The document discusses vibration analysis of lathe structures due to gear defects using finite element modeling. It aims to analyze the effects of unbalanced forces generated by machine elements like spindles and gears on the lathe structure. Both frequency domain and time domain analyses will be conducted using FEM. Experiments will also be conducted to measure vibration velocities on critical points of a lathe for different spindle speeds using a vibration tester. The results of experimental and theoretical analyses will be discussed to monitor machine elements and understand the effects of vibration on the lathe structure.
The transmission system transmits power from an automobile's engine to the rear driving wheels. It includes components like the clutch, gearbox, propeller shaft, differential, and rear axle. The clutch connects and disconnects the engine from the rest of the drivetrain. The gearbox uses different gear ratios to change the speed and torque delivered to the propeller shaft. The propeller shaft then transmits power to the differential, which uses planet gears to allow the rear wheels to rotate at different speeds while driving. The transmission system allows the vehicle to be driven at varying speeds and torque levels.
Mechanical engineering involves understanding core concepts in mechanics, kinematics, thermodynamics, materials science, and structural analysis. Mechanical engineers design and analyze machines, manufacturing plants, engines, transport systems, medical devices, and more. Examples of mechanical engineering include bicycles, CD players, video game consoles, snowmobiles, microelectromechanical systems, robotics, composite materials, biomechanics, aerospace engineering, and careers in automotive, manufacturing, utilities, HVAC, and space research industries.
This document summarizes chain drives. It discusses that chain drives transmit mechanical power from one place to another using a sequence of linked items forming an open or closed path. Chain drives have advantages like not slipping, maintaining precise speed, and easy installation, but are noisy, require lubrication, and are heavier than belts. It covers velocity ratio, factor of safety, classifications of chains, power transmission calculations, applications like hoisting and conveying, and examples of chain drives in vehicles and machinery.
Machine design, machine element, Belt drives and chain drives, selection of Belt - sheave and chain - sprocket, perancangan elemen mesin, transmisi sabuk dan rantai, pemilihan sabuk-puli dan rantai-sproket
This document provides an overview of different types of gear trains. It begins by introducing gear trains and their uses in mechanisms and machines. It then discusses simple gear trains and how to calculate their velocity ratios. Compound gear trains which can achieve higher speed reductions than simple gear trains are also covered. Other topics include reverted, epicyclic or planetary, and worm gear trains. Examples are provided to demonstrate how to calculate parameters for different gear train configurations.
The document discusses key concepts related to chain drives, including:
1) It defines common terms used in chain drives like pitch, pitch circle diameter, and velocity ratio.
2) It describes different types of chains including hoisting/hauling chains, conveyor chains, and power transmitting chains like roller chains and silent chains.
3) It provides equations for calculating important chain drive dimensions and specifications like length of chain, center distance, factor of safety, power transmitted, and number of teeth on sprockets.
Gear Drives for Diploma Students first and second YearMechTech3
Here is the PPT on the Gear Drives for Diploma Students of first and second year. Based on Mechanical Engineering diploma. The data for PPT is collected From book so don,t worry about PPT.
this project is design of bevel gear box
A Gearbox is a device that used for transmitting power from the Power source to
the output shaft. A gearbox has a set of gears that are enclosed in a casing. The gears are
mounted on shafts which rotate freely about their axis
UNIT-4-ENERGY STORING ELEMENTS AND ENGINE COMPONENTS.pptxkarthi keyan
ENERGY STORING ELEMENTS AND ENGINE COMPONENTS
Springs – Design of helical springs – Design of Leaf, Belleville springs and Torsion springs – Flywheels considering stresses in rims and arms for engines and punching machines. Design of Crankshaft.
This document provides information about different types of springs and their applications. It discusses helical springs, leaf springs, disc or Belleville springs, and conical springs. For helical springs specifically, it describes the types of helical springs, advantages of helical springs, stresses in helical springs, deflection of helical springs, and the design procedure for helical compression springs. It also provides information on leaf springs, flywheels, connecting rods, and crankshafts.
This document provides information about different types of springs and their applications. It discusses helical springs, leaf springs, disc or Belleville springs, and conical springs. For helical springs specifically, it describes the types of helical springs, advantages of helical springs, stresses in helical springs, deflection of helical springs, and the design procedure for helical compression springs. It also provides information on leaf springs, flywheels, connecting rods, and crankshafts.
Power transmission systems are used to transmit motion from a prime mover to end equipment. They include gears, belts, chains, and shafts. Gears transmit motion through meshing teeth and can be used to increase or decrease speed. Belts and chains are used over long distances. Motion is converted between rotary and linear using various mechanisms like lead screws, rack and pinion, and cams. Bearings support shafts and provide low friction rotation. Couplings connect transmission components.
Design, fabrication and performance evaluation of melon shelling machineeSAT Journals
The document describes the design, fabrication, and testing of a melon shelling machine. It discusses the methodology used, including design calculations for components like the shelling cylinder, shaft, belt drive, and bearings. Testing showed the machine achieved 62.5-70.95% shelling efficiency depending on whether a flat bar or flexible rubber was used for shelling. While the flexible rubber achieved higher shelling, it also resulted in more partially shelled seeds. Overall, the machine was successful in improving melon shelling performance compared to traditional methods.
Introduction to Gears & Dynamometers (Theory of Machines)Ishan Parekh
Gears are used to transmit rotational motion from one shaft to another. The three main types of gears are spur gears, helical gears, and bevel gears. Spur gears have teeth parallel to the axis of rotation and are used to transmit power between parallel shafts. Helical gears are cut at an angle, which allows them to engage more smoothly than spur gears. Bevel gears are used when the direction of shaft rotation needs to change, such as at right angles. Dynamometers are used to measure engine power output. Absorption dynamometers like the Prony brake and rope brake absorb power through friction, while transmission dynamometers measure torque transmitted through a transmission system.
Chain drives are commonly used to transmit power in agricultural machinery. They consist of linked metal plates connected by pins in an endless loop. This allows for flexibility while enabling large tensile forces to be transmitted. Key advantages of chain drives are their ability to transmit power at slower speeds and their durability in operating in harsh environments. Proper lubrication and maintenance is required. Gears are another type of positive drive that transmit motion between two rotating shafts via toothed wheels. They can be used to increase or decrease speed depending on the relative sizes of the input and output gears. Standard gear types include spur gears, helical gears, bevel gears, and worm gears.
This document provides details on the design and working of a gearless transmission mechanism. It consists of 3 bent links that transmit rotational motion from an input shaft to an output shaft located at a 90 degree angle without using gears. This allows motion to be transmitted through restricted spaces efficiently with minimal friction. The mechanism finds various industrial applications and can transmit power at angles between 0-90 degrees. It has been shown to achieve efficiencies as high as 90-92% compared to typical gear efficiencies of around 55%. The document then outlines the components, materials and design of the gearless transmission mechanism.
The document discusses gear drives and gearboxes. It provides an overview of gear terminology, types of gears, gear profiles like involute and cycloidal curves, gear manufacturing processes like hobbing and shaping, and considerations for gear design such as interference and undercutting. The key points are that gears transmit motion and power between rotating shafts via their teeth, involute profiles are most commonly used due to advantages like constant velocity ratio, and hobbing is a widely-used machining process for gear tooth formation.
The document describes the design of a zero-turn radius system for a John Deere 5065E tractor. The system uses hydraulic tie rods attached to a double-acting cylinder to enable the rear wheels to rotate independently, allowing the tractor to turn within its own width. Calculations are shown for sizing the steering and tie rod cylinders and rods. The design also incorporates a hydrostatic transmission system to provide infinitely variable speed control for the rear wheels to facilitate zero-turn maneuvers. Performance simulations and a cost analysis are presented to evaluate the technical feasibility and cost-effectiveness of the zero-turn design.
The Analysis of The Effect of System Parameters on the RV Reducer Dynamic Cha...IJRESJOURNAL
ABSTRACT: In order to ensure the motion accuracy, transmission efficiency and load carrying capacity of the robot with high precision RV reducer, under the condition of certain parameters, this paper analyzes the contact deformation relationship of the cycloidal gears in theory, the engaging force of the needle teeth, and then obtain the number of teeth when the cycloidal wheel and the needle wheel match wtih each other at the same time. The model of RV-80E reducer was established by using SolidWorks software, and then use the ADAMS to do the dynamics simulation . In this situation, The effect of the meshing force between cycloidal and needle teeth in RV reducer is explored when changing a single parameter such as short range coefficient、the radius of needle tooth’s center circle、the radius of needle tooth、the teeth’s number of cycloidal gear. Then find the best range of parameters to ensure the force between cycloidal and needle teeth .It provides useful conclusions for improving the performance of the overall transmission stability and carrying capacity of the gear unit. It also provides a reference for research methods on dynamics problems which use the virtual prototyping ,and have great significance for the production and design of RV reducer in the future.
The document discusses the design and fabrication of a multi-angular gearless mechanism. It begins with an introduction to power transmission and gear transmission systems. It describes the advantages of gearless transmission over geared transmission, including higher efficiency and flexibility to transmit power at various angles. The document then discusses the methodology used, which includes studying research papers, selecting materials, designing parts, modeling and simulation, and fabrication and assembly. It provides details of the various designed parts and working of the mechanism. The fabrication process involves measuring, cutting, grinding, drilling and assembling the various components.
Design and Analysis of Centrifugal Governor: A ReviewIRJET Journal
This document provides a review of the design and analysis of a centrifugal governor. It begins with an abstract describing the objective to identify stress concentration areas and areas most susceptible to failure when the governor rotates. It then discusses the materials used for different governor parts, including stainless steel for the spindle and arms due to its strength. The document outlines the governor design process and criteria. It also analyzes the stresses on parts like the shaft and bearings. Graphs show how the governor's axial deflection increases with angular velocity. The analysis identifies high stress concentration areas that require strengthening to avoid failure.
This document discusses gear generation and finishing operations. It begins by introducing gears and their uses in power transmission systems. Various gear manufacturing methods are then described, including casting, plastic molding, and machining. Gear shaping is discussed as a machining method, where a multi-point cutting tool is used to cut gear teeth into a gear blank. Key parameters for gear shaping like cutting speed and indexing motion are also outlined.
This document provides an overview of gear generation and finishing operations. It defines key gear terminology and describes various methods for manufacturing gears, including gear shaping, gear hobbing, and other machining processes. Gear shaping involves cutting gear teeth using a reciprocating multipoint cutter. Gear hobbing uses a rotating cutter called a hob to cut teeth as it is fed into a rotating gear blank. The document explains the processes, parameters, advantages and limitations of various gear cutting methods.
Similar to MET 105 Module 5 power-transmission (20)
This document contains 6 exercises related to calculating the thermal efficiency of steam power plants operating on different Rankine cycle configurations including:
1) Ideal Rankine cycle
2) Ideal reheat Rankine cycle
3) Reheat Rankine cycle with specified turbine inlet/exit conditions
4) Regenerative Rankine cycle with one open feedwater heater
5) Reheat-regenerative cycle with one open feedwater heater, one closed feedwater heater, and one reheater.
The 6th exercise asks to determine the fractions of steam extracted from the turbine and the thermal efficiency for a plant operating on the reheat-regenerative cycle described in item 5 above.
Dial indicators are precision measuring tools used by machinists and toolmakers. They have several uses including quickly checking alignment, correctly positioning workpieces, and inspecting large quantities of parts. Dial comparators are also precise measuring instruments that indicate small differences between a standard and a workpiece on a magnified scale. They are used to check that parts are within required size limits. Balanced dial indicators have figures in both directions from zero while continuous reading types are numbered continuously. There are several types of dial indicating gauges such as snap gauges, calipers, and hole gauges that are used to determine if parts meet size requirements.
This document provides information about various precision measurement tools including telescoping gauges, three-point gauges, feeler gauges, and gauge blocks. It describes how each tool is used and lists important specifications, parts, advantages, applications, and care instructions. Multiple questions are answered that review these concepts, such as describing how to measure the angle of a V-groove using precision balls and rollers, listing gauge block uses, and calculating gauge block buildups for given measurements.
The document discusses different types of vernier micrometers used for various measuring applications. It describes depth micrometers which measure depth, inside micrometers which measure inside diameters and surfaces, and tubular inside micrometers which are useful for internal cylindrical measurements. It also discusses micrometer parts like the ratchet, lock nut, and changeable anvils. Methods for measuring thread diameters and pitches using special thread micrometers are provided. Recent micrometer designs include indicating, direct reading, dual reading, and all-electronic models.
The document provides information on using various precision measuring tools like vernier calipers, dial calipers, depth gauges, and discusses:
- The main parts of a vernier caliper and how verniers of different precision work
- The functions of dial calipers for inside, outside, depth, and step measurements
- Procedures for using gear tooth and knife edge vernier calipers to measure gear dimensions
- Features and uses of height gauges
- Components of a scriber point attachment
- Steps for using a vernier depth gauge and precautions to ensure accuracy
The document discusses various measurement tools used in machine shops including steel rules, calipers, depth gauges, and combination sets. It provides examples of how to take different types of measurements and describes the purposes of specific tools like hook rules for measuring from shoulders, calipers for inside and outside measurements, and surface plates for providing a reference surface. Common sources of measurement errors on steel rules are also identified.
This document provides examples of converting between units in the inch and metric systems of measurement. It gives the common units of length for each system and examples of converting between inches and centimeters and between inches and millimeters. Conversions include inside diameters of pipes, lengths of bolts, and various lengths between the systems.
This document provides information on different types of boilers and their components. It discusses fire tube boilers and water tube boilers. It also describes auxiliary equipment that can be fitted to boilers like pressure gauges, water gauge glasses, and pressure relief valves. Additionally, it covers topics like superheaters, economizers, different types of fuel firing systems, evaporation, heat pipes, and performance measures for tubular evaporators.
Heat exchangers transfer heat between two or more fluids. There are four main factors that affect heat transfer: materials, fluids, temperature difference, and contamination. Common types of heat exchangers include double pipe, shell and tube, kettle, air coolers, plate, and calandria. Key features of different heat exchanger types like shell and tube, double pipe, and air coolers are described.
This document discusses heat exchangers and one-dimensional steady conduction. It provides equations and examples for conduction through plane slabs, composite walls, cylindrical layers, and spherical layers. It also discusses the purpose of insulation, critical insulation thickness, and factors that affect thermal conductivity. Dimensionless numbers for convective heat transfer like Reynolds number, Prandtl number, and Nusselt number are defined. Empirical relationships are provided for forced and natural convection.
1. Radiation can be described using both wave and particle theories, with photons traveling at the speed of light and having energy levels related to their frequency.
2. Thermal radiation emitted from surfaces is within the wavelength range of 10-7 to 10-4 m. The human eye can detect wavelengths from 3.8x10-7 to 7.6x10-7 m, known as visible radiation.
3. A blackbody is an idealized radiating surface that absorbs all radiation falling on it and reaches the maximum possible emissive power at each wavelength for a given temperature.
This document provides information on different types of boilers and their components. It discusses fire tube boilers and water tube boilers. It also describes auxiliary equipment that can be fitted to boilers like pressure gauges, water gauge glasses, and pressure relief valves. Additionally, it covers topics like superheaters, economizers, coal firing, gas firing, evaporation, heat pipes, and performance of tubular evaporators.
The document discusses good operating practices and safety precautions for maintaining heat exchangers. It describes the tools and equipment needed, which are divided into working tools and safety equipment. Important safety practices include ensuring systems are shut down and isolated, draining heat exchangers before opening, and following confined space procedures. Preventative maintenance and troubleshooting responsibilities are also outlined.
1. Condensers convert vapor back into liquid by transferring heat from the vapor to a cooling medium, usually through tubes.
2. The main parts of a condenser are the shell, tube sheets, water boxes, and tubes. Steam flows over the tubes on the shell side while cooling water flows through the tubes.
3. There are different types of condensers including surface condensers, jet condensers, and barometric or low-level condensers depending on how the steam and cooling water interact.
- Heat exchangers transfer heat between fluids through solid surfaces. Heat is transferred by convection between the fluid and solid surface.
- The rate of heat transfer depends on the convection heat transfer coefficient (h), which depends on fluid properties and velocities.
- Dimensionless numbers like Reynolds, Prandtl, and Nusselt relate fluid flow regime (laminar or turbulent) to heat transfer rate.
- Empirical relationships using these numbers predict heat transfer for forced and natural convection in different geometries.
- The overall heat transfer coefficient (U) accounts for resistances of conductive and convective boundaries in composite systems.
1. MET -105
POWER TRANSMISSION
Definitions
A rotating machine is one in which the main working components rotate about a fixed
center in a regular manner. Most such machines incorporate additional subsidiary
mechanisms such as linkages, slides, gears and reciprocating components, and many
of the operating principles that apply to the rotating assembly also apply to these other
elements.
Although there are many different types of rotating machines, they can all be classified into
three basic groups in terms of their function.
Driving machines (engines or prime movers)
This group includes all machines whose purpose is to drive other machines. Examples
include :
Electric motors
Steam turbines
Diesel engines
Petrol engines
Air motors
The common characteristic of these machines is that they convert an energy input of
varying kinds into a mechanical output in the form of a rotating drive shaft.
Transmission machines
These are machines whose purpose is to transmit mechanical energy from a driving to
a driven machine. Examples include :
Gearboxes
Differentials
Variable speed drives
Chain
Belts
2. The mechanical energy transmitted often undergoes a speed transformation and these
machines often incorporate some means of drive disengagement such as a clutch.
Driven machines
These machines cannot operate independently and need to be coupled to a driving
machine. Examples include:
Pumps
Compressors
Fans
Generators
Blenders
Machine tools
This group is by far the largest and includes a large number of different types of
machines. The common characteristic is that the energy input is normally in the form of
a rotating drive shaft while output may be in a variety of forms including kinetic or
pressure energy of a fluid, electrical energy, kinetic or potential energy of solid
materials, etc.
Power Transmission
There are three major systems in use for transmission of rotary motion between
adjacent shafts : belts, chains and gears.
BELT DRIVE
One of the most common elements in power transmission systems, belt drives give dependable
and cost effective power transmission with a minimum of maintenance.
There are four basic types of belts used in power transmission
1. Flat belts
2. V-belts
3. Toothed timing belts
4. Ribbed
V-BELT TYPES
3. Most V-belt drives used in industrial applications fall into two categories: heavy duty
(industrial) and light duty (fractional horsepower). There are primarily two types of
industrial belts: the classic cross sections (A, B, C, and D) and the narrow cross sections
(3V, 5V, and 8V) (Molded notch construction belts are usually designated with an X after the
section letter. A 3V molded notch belt would be designated 3VX.)
Fractional-horsepower belts are used most often on drives transmitting less than 1 horsepower.
Fractional-horsepower belts are available in the following sections: 2L, 3L, 4L, and 5L. A V-belt
is specified by cross section and length.
Principles of Operation
V-belts are normally used to transfer power between two shafts whose axes are parellel
and some distance apart.
Figure 1. Typical V-belt arrangements
The belt is mounted on pulleys that are attached to the driving and driven shafts and the
drive relies on friction between the belt and the pulleys for its operation. The belt sits in
the groove of the pulley and makes contact with the sides of the groove as shown in
Figure2
.
4. Figure2
Classic cross section.
Narrow cross section.
Molded notch belt.
Joined belt cross section.
Heavy problem solving joined
5. Light duty belt dimensions.
Classic cross-sectional dimensions. Narrow cross-sectional dimensions.
V-Belt Length
V-belt length can be measured in three ways: outside circumference (OC), datum length
(DL), and effective length (EL). The outside circumference is measured by wrapping a tape
measure around the outside surface of the belt.
Datum Length. Datum length is a recent designation adopted by all belt manufacturers in order
to retain standard belt and sheave designations while more accurately reflecting the changes that
have occurred in belt pitch length and pitch-line location within the belt (pitch length is the
length of the neutral axis of the belt).
Effective Length. The effective length is defined as the measured center distance plus the outside
circumference of one of the inspection sheaves.
6. BELT DRIVES
Total measuring force
Schematic of a V-belt measuring fixture.
Misalignment
There are three primary sources of misalignment in belt-drive systems:
1. Driver and driven shafts are not parallel (both horizontal and vertical planes).
2. Sheaves are not located in line axially with respect to one another on the shafts.
3. Sheaves are tilted due to improper mounting (wobble while running).
Sheave groove inspection.
SYNCHRONOUS BELTS
Synchronous belts are toothed belts in which power is transmitted through positive
engagement between belt teeth and pulley or sprocket grooves rather than by the wedging
friction of V-belts. advantages of synchronous belts over other modes of power transmission
include a wider load/speed range, lower maintenance, increased wear resistance, and a smaller
amount of required take up.
7. TYPES OF SYNCHRONOUS BELT
Synchronous belt profiles.
Modified Curvilinear Belts
The modified curvilinear belt tooth form is a refinement of the curvilinear system. The belt
tooth and sprocket groove forms were optimized for smoother belt tooth entry/exit properties
and improved belt tooth support in the sprocket grooves.
Curvilinear Belts
The curvilinear belt tooth form was developed to provide increased load capacity and
performance over trapezoidal belts. The curvilinear belt consequently has a higher horsepower
capacity than does a comparably sized trapezoidal belt
Timing Belts
Timing belts were the first family of synchronous belts introduced to the market and were
designed with trapezoidal teeth. The belt horsepower ratings are relatively low compared to
curvilinear or modified curvilinear belts introduced later, but the synchronization qualities are
excellent for accurate positioning or registration sensitive applications
8. Pitch
The word „pitch‟ is commonly used in connection with many kinds of machinery and
types of mechanical operations and calculations. Its definition, as applied to mechanical
power transmission, is simple yet very important: the distance from a point to a
corresponding point. In figure 1 are several examples of this measurement of distance
from point to corresponding point.
Pitch Circle
Although the “pitch circle” is not visible, its dimension can be stated specifically as the
pitch diameter of a gear, sheave, sprocket, etc. These dimensions are a necessary part
of all rotary power-transmission calculations. These calculations are based on the
concept of disc or cylinders in contact, as illustrated in Figure 2.
The rotation of one disc causes the disc with which it is in contact to rotate. This
concept assumes that no slippage occurs between the surfaces of the discs. The
surfaces then travel equal distances at equal surface speeds.
9. . One revolution of a 2-inch circle will result in a ½ revolution of a 4-inch circle
4” PITCH DIA.
2” PITCH DIA.
One revolution of a 4-inch circle will result in two revolutions of a 2-inch circle
Shaft speeds are inversely proportional to pitch diameters.
Using the term “driver” to indicate the driving gear, sprocket, or sheave, and the term
“driven” to indicate the gear, sprocket, or sheave that is being driven, the ratio can be
stated or expressed in the form of an equation, as the follows :
Driver Rotational Speed Driven Pitch Diameter
=
Driven Rotational Speed Driver Pitch Diameter
The equation can be simplified by substituting letters and numbers for the words. Use
the letter (N) to signify speed, the letter (D) to indicate pitch, the number (1) to indicate
the “driver”, and the number (2) to indicate the “driven”.
Driver rotational speed = N1
10. Driven rotational speed = N2
Driver pitch diameter = D1
Driven pitch diameter = D2
The equation then becomes
N2 D1
N1 D2
These equations may be used to find unknown values by simple substitution of known
values in the appropriate equation. Following is an example of the use of each of one of
these equations.
Example 1
The pitch diameter of the driver unit that is turning at 100 rpm is 2”. What will be the
speed of the driven unit of its pitch diameter is 4”?
4” PITCH DIA.
DRIVER
100 RPM
2” PITCH DIA.
Figure 6.
Known values :
N1 = 100
D1 = 2
D2 = 4
D1 x N 1 2 x100 200
Unknown N2 = N2 or or 50
D2 4 4
Speed of driven unit is 50 rpm.
11. Example 2
The driver unit is turning at a speed of 600 rpm. The driven unit is turning at 2000 rpm
and its pitch diameter is 3”. What is the pitch diameter of the driver unit?
DRIVER 3” PITCH DIA.
600 RPM
DRIVEN
2000 RPM
Figure 7.
N1 = 600 RPM
N2 = 2000 RPM
D2 = 3“
N 1x D 2 2000 x 3 6000
Unknown D1 = or D 1 or or 10
D1 600 600
The pitch diameter of the driver unit is 10”
Speed, Torque and Power
The power generated by driver equipment and transmitted to the driven is used at
different rotational speeds.
If the power is assumed to be transmitted without any mechanical losses, so the total
value of the power will be the same for both driver and driven.
As P = T.
2 N
P = T.
60
Where
P = Mechanical Power
12. = Angular speed
T = Torque
Then, between driver and driven shafts and assuming no mechanical losses
P1 = P2 (Power is completely transmitted)
2 N1 2 N2
T1 T2
60 60
T1.N1 = T2.N2
Note : The homogeneity of units in the application of these formulae is required.
In S.I. units :
P = watts (w) kW or 1 HP = 746 Watts
T = N.m
= radians / sec
output power
efficiency ( ) =
input power
In order to be able to transmit power, the belt must be under tension so that it is forced
down into the groove. The depth of the groove is always greater than the thickness of
the belt, however, and the belt should never bottom in the groove. The operation of the
belt and its ability to transmit power depend on the size of the friction force and the arc
of contact of the belt. The greater the arc of contact the more power the belt can
transmit. (Figure 3).
LARGER ARC OF CONTACT
ARC OF CAN TRANSMIT MORE
CONTACT POWER
Figure 3. Relationship between power and arc of contact
13. As well as performing its primary function of transmitting power, a V-belt can be used to
change the speed of the driver output and hence the torque transmitted to the driven
unit. There are three basic alternatives as shown on Figure 4.
SPEED RATIO
1:1
SPEED
INCREASE
SPEED
DECREASE
DRIVER DRIVEN
Figure 4. Alternative arrangements for V-belt drives
The speed ratio between the two pulleys of a belt drive can be calculated from a simple
formula.
driver pulley diameter ( mm )
Driven speed (RPM) = x driver speed ( RPM )
driven pulley diameter ( mm )
It is generally accepted that V-belt drives are limited to belt speeds between 300 and 3000
meters per minute (1000-10,000 feet per minute). If required to operate at higher speeds then
dynamic balancing of the pulleys becomes increasingly important
TYPES OF BELTS
There are many types of belts, some of them are commonly used and some other are
rarely used. In the following the common types of belts:
14. 1 round belts
2. flat belts
3. single V-belt
4. banded V-belt
5. linked V-belt
6. timing belt
7. V-ribbed belts
The common types of belts
BELT TENSION TECHNIQUES
1. Belt tension by using slotted holes of the bolts of the motor base
2. Motor with slide rail for the whole base
3. Pivoted motor base
4. Belt tension by using idler pulley
15.
16. CHECK OF BELT TENSION
1 By using human sense and experience ( by hand sensitivity )
2 by depress the belt and measuring the deflection
3 by using the mechanical belt tension tool
4 by measuring the belt elongation after applying tension
5 by measuring the belt vibration frequency ( advanced method )
18. CHAINS FOR POWERTRANSMISSION
Chain drives consist of an endless series of chain links which mesh with toothed wheels, called
sprockets. The sprockets are keyed to the shafts of the driving and driven mechanisms.
A roller chain has two kinds of links—roller links and pin links—alternately assembled
throughout the chain length
Dimensions for roller-chain identification
Chordal action is a serious limiting factor in roller-chain performance. It may be described as
the vibratory motion caused by the rise and fall of the chain as it goes over a small sprocket
19. Chordal action.
Figure shows schematically a roller chain entering a sprocket (A); the line of approach is not
tangent to the pitch circle. The chain makes contact below the tangency line, is then lifted to
the tangent line (B),and then is dropped again (C) as sprocket rotation continues. Because of its
fixed-pitch length, the pitch line of the link cuts across the chord between two pitch points on
the sprocket and remains in this position relative to the sprocket until the chain disengages.
Principles of Operation
Chains and sprockets fulfil the same basic function as belts and pulleys in transferring
power between two parallel shafts. Instead of relying on friction, a chain drive is a
positive drive in which the links of the chain engage with specially formed teeth on the
sprocket.
Standard roller chain is made up of alternate roller links and pin links.
20. The pitch of the chain is determined by the length of the side plates, and the bushings
and pins are press-fitted into the side plates. The pins of a special joining link may be
longer and grooved to take spring clips as shown in Figure 11.
Figure 9. Chain and Sprocket
. Standard roller chain
21. . Special joining link
Pitch, width and roller diameter are the critical dimensions of roller chain.
Types and Arrangements
Standard roller chain is available in single and multi-strands form, and the number of
strands required will depend on then power to be transmitted. Double pitch chains are
also available. They are cheaper, and are suitable for light loads and low speeds.
Chain drives are used most commonly as horizontal drives and any slack in the chain
resulting from wear, should accumulate on the lower strands as shown in Figure 15.
Vertical drives should be arranged so that accumulated slack falls into the driven
sprocket rather than away from it, to prevent misengagement.
22. Figure 14. Double pitch chain
RIGHT
WRONG
Figure 15. In a horizontal drive, slack should accumulate on the lower strand
Where chain tensioners are used they should be used on the side of the chain where
the slack is expected to accumulate (Figure 17).
RIGHT WRONG
23. Figure shows Accumulated slack in a vertical drive should fall into, rather than away
from the driven sprocket
Figure 17. Using a chain tensioner
DRIVE TYPE
Belt Drives Chain Drives
1. Belt drives rely on friction between 1. Chain drive is a positive drive in
the belt and pulleys for their which the links of the chain engage
operation. with specially formed teeth on the
sprocket.
2. needs pulley alignment 2. needs sprockets alignment (more
sensitive for misalignment )
3. needs belt tension adjustment 3. needs chain tension adjustment
4. sensitive to temperature 4. needs lubrication
5. Sensitive to any liquid, oil, dust and 5. Sensitive to dust and environmental
environmental conditions. conditions
6. Considerable speeds 6. Limited in the transferred speed (
up to 1350 meters per minute )
7. Slippage always exists so that it is 7. Accurate speed transfer.
inaccurate in speed transfer.
8. usually smooth running 8. usually noisy running
9. cheap in the cost 9. expensive in the cost
24. GEARS AND GEAR BOXES
Gear Drives
Gear drives are used to transmit power from one machine to another where changes of
speed, torque, direction of rotation or shaft orientation are required. They may consist of
one or more sets of gears depending on the requirements. In most cases the gears are
mounted on shafts supported by an enclosed casing which also contains a lubricant.
Principles of Operation
A gear is a form of wheel with teeth machined around the outer edge which allow it engage
with similar wheel or rack. The most important features of a gear are the tooth profile or
cross-sectional shape, and the number of teeth. In order to understand the geometry of
gears. However, there is a limit to the torque that can be transmitted by friction and so teeth
are cut into the outer edges of the discs to provide a means of positive engagement as shown
in figure 1.
The imaginary circles on which the gears are cut are called the pitch circles, and the pitch
circle diameter is the major dimension on which gear geometry is based. The other
important dimension is the pressure angle. This is the angel between a tangent to the pitch
circle and the line of contact of two mating teeth as shown in figure 2.
The Teeth provide a means of positive engagement
25. If two gears are to mesh properly they must have the same pressure angle. Standard
pressure angles of 14.5 and 20 are used with 20 being the most common.
PRESSURE
ANGLE
LINE OF
ACTION
PRESSURE
ANGLE
Fig.2 The pressure angle
In practice, gears are cut to provide running clearance between mating teeth. This
known as backlash.
Figure 3. Terms used in circular gear geometry
26. In practice, gears are cut to provide running clearance between mating teeth. This is
known as backlash (figure 4).
Figure 4. Gears are cut to provide backlash
The characteristics of mating gears are often described by the term, diametral pitch.
This term refers to the ratio of the number of teeth to the pitch circle diameter of the
gear and reflects the size and shape of the teeth. Hence two mating gears must also
have the same diametral pitch as well as the same pressure angle.
There are several ways in which diametral pitch can be calculated.
Diametral pitch =
circular pitch
number of teeth
Diametral pitch =
pitch circle diameter
number of teeth 2
Diametral pitch =
outside diameter
D PZ P : Pitch Circle
Z : Number of teeth
D : Diameter
The speed relationship between two mating gears depends on the number of teeth on
each gear and can be determined as follows :
Speed of driven gear = spead of driver x no. of teeth on driver
(RPM) (RPM) no. of teeth on driven
27. Types and arrangements of Gear
A gear train consists of one or more gear sets intended to give a specific velocity ratio,
or change direction of motion. Gear and gear train types can be grouped based on their
application and tooth geometry.
Table 1. Gear Types Grouped According to Shaft Arrangement
arallel Axes Non-Intersecting (Non- Rotary to Translation
Intersecting Axes
parallel) Axes
Spur Gears Bevel gears: Hypoid gears Rack and Pinion
Helical Gears Straight bevel Crossed helical gears
Herringbone or double
Zerol bevel Worm gears
helical gears
Spiral bevel
Spur gears (Fig. 5): Spur gears connect parallel shafts, have involute teeth that are
parallel to the shafts, and can have either internal or external teeth. Notes:
1. Spur gears are inexpensive to manufacture.
2. They cause no axial thrust between gears.
3. They give lower performance, but may be satisfactory in low speed or simple
applications
4. Simple overall design and assembly.
28. Figure. 5 Spur Gears
Helical gears (Fig. 6): Helical gears also connect parallel shafts, but the involute teeth
are cut at an angle (called the helix angle) to the axis of rotation. Note that two mating
helical gears must have equal helix angle but opposite hand. These are found in
automotive transmissions, and any application requiring high speed rotation and good
performance. Notes:
1. Helical gears run smoother and more quietly than spurs (due to continuous tooth
mating).
2. They have a higher load capacity (teeth have a greater cross section).
3. They are more expensive to manufacture.
4. Helical gears create axial thrust.
Figure 6. Helical gears
Herringbone gears (Fig. 7): To avoid axial thrust, two helical gears of opposite hand
can be mounted side by side, to cancel resulting thrust forces. These are called double
helical or herringbone gears
29. Figure. 7 Herringbone gears
Bevel gears (Fig. 8): Bevel gears connect intersecting axes, and come in several types
(listed below). For bevel gears, the pitch surface is a cone, (it was a cylinder in spur and
helical gears) and mating spiral gears can be modeled as two cones in rolling contact.
Types of bevel gears:
1. Straight bevel: These are like spur gears, the teeth have no helix angle. Straight bevel
gears can be
a. Miter gears, equal size gears with a 90 degree shaft angle,
b. Angular bevel gears, shaft angle other than 90 degrees, or
c. Crown gears, one gear is flat, has a pitch angle of 90 degree.
2. Spiral bevel gears(Fig. 8a): Teeth have a spiral angle which gives performance
improvements much like helical gears
3. Zerol bevel gears (Fig. 8b): Teeth are crowned, so that tooth contact takes place first
at the tooth center. Zerol bevel gears offer performance that is equivalent to that of
straight bevel gears and are spiral bevel gears with a spiral angle of 0°. They offer the
advantage of low axial thrust over spiral bevel gears.
31. Figure 8b. Zerol bevel gears
Hypoid gears (Fig. 9): Similar to spiral bevel gears, but connect non-parallel shafts that
do not intersect. The pitch surface of a hypoid gear is a hyperboloid of revolution (rather
than a cone, the pitch surface in bevel gears), hence the name. Hypoid pinions (the
smaller driving gear) are stronger than spiral bevel pinions because the helix angle of
the pinion is larger than that of the gear. Hypoid gears are found in auto differentials. I
also know that a hypoid gear set is used in my NH baler, connecting the flywheel to the
rear driveshaft.
Figure 9. Hypoid gears
32. Crossed helical gears (Fig. 10): Helical gears that connect skew shafts. The teeth
have sliding motion and therefore lower efficiency. One application is connecting
distributer to cam shaft in pre-electronic ignition vehicles.
Figure 10. Crossed helical gears
Worm Gears (Fig. 11): The driving gear is called a worm, and typically has 1, 2, or four
teeth. The low number of teeth on the worm can result in a very large velocity ratio.
These can also be designed to be non-backdriveable, and can carry high loads.
Because of sliding action, efficiency is low.
Figure 11. Worm Gears
33. Rack and Pinion (Fig. 12): These transmit rotary motion (from the pinion) to
translational motion (of the rack). The rack is a gear with infinite radius; its teeth,
although flat sided, are involute. The rack and pinion is commonly used in steering units
and jacks.
Figure 12. Rack and Pinion
Gear reduction arrangements
Whatever type of gear is employed, the arrangement may involve one or more pairs of
gears depending on the degree of speed reduction required
Gears are generally made from steel or cast iron and are surface hardened in order to
increase the wear resistance.
Figure 13. Gear Reduction
34. GEAR DRIVES AND SPEED REDUCERS
Common Gear Types
Common types of gears used in industrial gear drives include spur, helical, double-helical,
bevel,spiral bevel, hypoid, zerol, worm, and internal gears
35. Double helical drives
Epicyclic Gear Drives
In an epicyclic gear drive, power is transmitted between prime mover and driven machinery
through multiple paths. The term epicyclic designates a family of designs in which one or more
gears move around the circumference of meshing, coaxial gears, which may be fixed or rotating
about their own axis. Individual gears within an epicyclic drive may be spur, helical, or double-
helical.Because of the multiple power paths, an epicyclic gear drive will normally provide the
smallest drive for a given load-carrying capacity. Other advantages include high efficiency, low
inertia for a given duty, high stiffness, and a high torque/power capability
The basic elements of an epicyclic drive are a central sunwheel, an internally toothed annulus
ring,a planet or star carrier, and planet or star wheels. Depending on which of the first three
36. elements is fixed, three types of epicyclic drives are possible: a planetary gear drive, a star
gear drive, or a solar gear drive. In a planetary gear drive the annulus ring is fixed.
(A) High-speed gearbox, enclosed. (B) High-speed gearbox, showing internal parts.
GEAR-TOOTH WEAR AND FAILURE
Experience indicates that the vast majority of gear-tooth wear and failure types may be
summed up under nine basic headings in two classifications:
Classification A: Surface deterioration
1. Wear
2. Plastic flow
3. Scoring
4. Surface fatigue
5. Miscellaneous tooth-surface deteriorations
Classification B: Tooth breakage
6. Fatigue
7. Heavy wear
8. Overload
9. Cracking
37. Ridging. Rolling.
Destructive pitting. Spalling.
Severe scoring. Initial pitting.
38. Rippling Slight scoring.
COUPLINGS
Couplings are the devices used to connect two shafts with a common axis of
rotation. Couplings, no matter what type, all have one thing in common: they need
proper alignment. Any coupling that isn‟t aligned won‟t perform properly. No matter
how flexible its center member is, it‟ll wear out. This is the primary point in maintaining
couplings. There are two main types of couplings :
1. Rigid
2. Flexible
Rigid couplings
Rigid couplings usually require no further maintenance than correct alignment. Once
they are aligned, corrected sized coupling bolts should be installed and then tightened
to the correct torque for that bolt. Since there are no moving parts, no wear should
occur. On inspection, the bolts should be checked to insure that they haven‟t loosened.
Flexible couplings
Flexible couplings require more maintenance than do rigid couplings. They should be
aligned to the same standards, as misalignment causes rapid wear. Flexible couplings
can be divided into two classes:
Mechanical - Flexing
Material - Flexing
39. Mechanical flexible couplings depend on some form of a mechanically flexible element.
In this class falls the gear, chain, grid, spindle, and universal joint .These all require the
use of lubrication to prevent wear. If they aren‟t lubricated, they „ll wear excessively
fast. The lubricant should be clean. If sufficient lubrication is not applied, metal-to-
metal contact will occur between contacting metal parts under load and rapid wear will
occur.
The following guidelines should be used :
1 Gear – half full of clean lubricant
2 Chain – packed with clean oil
3 Grid – packed with clean grease
4 Spindle – same as gear
5 Universal joint – dependant on application
Material flexible couplings use some form of flexible material between the two coupling
halves to absorb some limited misalignment but this isn‟t a cure-all. The inspector
should give attention to the flexible member during his inspection. If the member has
been hot or is cracked and showing wear, it should be replaced and the alignment
checked. When the alignment is bad, it flexes the material, heats up, and wears more
rapidly than it should.
40.
41.
42.
43. FLEXIBLE COUPLINGS
FOR POWER TRANSMISSION
A flexible coupling is a mechanical device used to connect two axially oriented shafts. Its
purpose is to transmit torque or rotary motion without slip and at the same time compensate
for angular, parallel,and axial misalignment.
CAUSES OF COUPLING FAILURE
Most failures due to internal faults are the result of improper or poor machining. Another
major cause of failure due to internal faults is improper product design. On mechanical-flexing
couplings, the major problem is to provide adequate lubrication between the sliding contact
faces, since lack of a lubricating film between these high pressure surfaces will result in rapid
wear. On material-flexing couplings, improper design of the flexing-element section and
method of attachment to the hubs are the main causes of premature fatigue.
Most common causes of failure due to external conditions have to do with improper
selection, improper assembly, and excessive misalignment
Coupling Selection
Proper selection as to the type of coupling is the first step of good maintenance. A well-chosen
coupling will operate with low cross-loading of the connected shafts, have low power
absorption, induce no harmful vibrations or resonances into the system, and have negligible
maintenance costs. The primary considerations in selecting the correct type of flexible
couplings, as well as its size and style, are
1. Type of driving and driven equipment
2. Torsional characteristics
3. Minimum and maximum torque
4. Normal and maximum rotating speeds
5. Shaft sizes
6. Span or distance between shaft ends
7. Changes in span due to thermal growth, racking of the bases, or axial movement of the
connected shafts during operation
8. Equipment position (horizontal, inclined, or vertical)
9. Ambient conditions (dry, wet, corrossion, dust, or grit)
10. Bearing locations
11. Cost (initial coupling price, installation, maintenance, and replacement).