2.4 bevel gear
•
1 like•226 views
This document discusses bevel gears, which are useful for changing the direction of shaft rotation by 90 degrees. Bevel gears can have straight, spiral, or hypoid teeth and are commonly used in applications like locomotives, marine vessels, automobiles, and industrial machinery. The document explains the components of bevel gears like the pitch cone and cone center. It also discusses how to develop involute teeth on the cone surface of bevel gears. The advantages of bevel gears are also summarized, such as their quiet operation and high efficiency compared to other gear types.
Recommended
More Related Content
What's hot
What's hot (20)
Similar to 2.4 bevel gear
Similar to 2.4 bevel gear (20)
More from Kiran Wakchaure
More from Kiran Wakchaure (16)
Recently uploaded
Recently uploaded (20)
2.4 bevel gear
- 1. Sanjivani Rural Education Society’s Sanjivani College of Engineering, Kopargaon-423603 ( An Autonomous Institute Affiliated to Savitribai Phule Pune University, Pune) NAAC ‘A’ Grade Accredited, ISO 9001:2015 Certified Subject :- Theory of Machines II T.E. Mechanical (302043) Unit 2 2.4 BEVEL GEAR By Prof. K. N. Wakchaure(Asst Professor) Department of Mechanical Engineering Sanjivani College of Engineering (An Autonomous Institute) Kopargaon, Maharashtra Email: wakchaurekiranmech@Sanjivani.org.in Mobile:- +91-7588025393
- 2. BEVEL GEARS Bevel gears are useful when the direction of a shaft's rotation needs to be changed They are usually mounted on shafts that are 90 degrees apart, but can be designed to work at other angles as well The teeth on bevel gears can be straight, spiral or hypoid Applications: locomotives, marine applications, automobiles, printing presses, cooling towers, power plants, steel plants, railway track inspection machines, etc. 2
- 3. STRAIGHT AND SPIRAL BEVEL GEARS 3PROF. K N WAKCHAURE
- 4. BEVEL GEARS 4PROF. K N WAKCHAURE Disadvantages •High costs. •Bevel gears are manufactured in pairs. For maintenance and repair, both gears must be replaced. •In order to achieve high efficiency, bevel gear sets must be positioned exactly, so the shafts must be adjusted very precisely. •Limited translation range. Maximum ratio of 6:1 per bevel gear set. Spur gear stages are necessary in order to achieve a higher overall gear ratio. •Bevel gears are not recommended for high-speed reduction. At high speed, a bevel gear unit generates noise. Advantages •Quiet Operating noise (Quiet operation is particularly advantageous in environments such as theatres or airports.) •Increased torque capacity compared to worm gears of the same size. •High efficiency (rolling of bevel gears is very efficient compared to the sliding effect of worm gears (98.5%). The metal bevel gear teeth never come into direct contact with an oil film.) •Hollow shaft possible
- 6. Pitch cone: The pitch cone is the pitch surface of a bevel gear in a gear pair. Cone centre: The cone centre is the apex of the pitch cone. Pitch cone radius (r): The pitch cone radius is the length of the pitch cone element. Pitch angle (γ): The pitch angle is the angle that the pitch line makes with the axis of the gear. γ Back cone: The back cone is an imaginary cone the elements of which are perpendicular to the elements of the pitch cone at the larger end of the tooth.
- 7. DEVELOPMENT OF INVOLUTE TEETH ON CONE
- 8. sin 𝛾1 = 𝑟1 𝑂𝑃 sin 𝛾2 = 𝑟2 𝑂𝑃 sin 𝛾1 sin 𝛾2 = 𝑟1 𝑟2 𝛾1 + 𝛾2 = 𝜃 sin 𝛾1 = 𝑟1 𝑟2 ∗ sin 𝛾2 sin 𝛾1 = 𝑟1 𝑟2 ∗ sin 𝜃 − 𝛾1 sin 𝛾1 = 𝑟1 𝑟2 ∗ sin 𝜃 ∗ cos 𝛾1 ) − cos 𝜃 ∗ sin 𝛾1 dividing both the sides by cos 𝛾1 tan 𝛾1 = 𝑟1 𝑟2 ∗ sin 𝜃 ) − cos 𝜃 ∗ tan 𝛾1 𝛾1 = 𝑠𝑒𝑚𝑖𝑐𝑜𝑛𝑒 𝑎𝑛𝑔𝑙𝑒 𝑓𝑜𝑟 𝐵𝑒𝑣𝑒𝑙 𝐺𝑒𝑎𝑟 1 𝛾2 = 𝑠𝑒𝑚𝑖𝑐𝑜𝑛𝑒 𝑎𝑛𝑔𝑙𝑒 𝑓𝑜𝑟 𝐵𝑒𝑣𝑒𝑙 𝐺𝑒𝑎𝑟 2 𝜃 = 𝑆ℎ𝑎𝑓𝑡 𝑎𝑛𝑔𝑙𝑒 = 𝛾1 + 𝛾2 𝑟1 = 𝑝𝑖𝑡𝑐ℎ 𝑐𝑜𝑛𝑒 𝑟𝑎𝑑𝑖𝑢𝑠 𝑓𝑜𝑟 𝐵𝑒𝑣𝑒𝑙 𝐺𝑒𝑎𝑟 1 𝑟2 = 𝑝𝑖𝑡𝑐ℎ 𝑐𝑜𝑛𝑒 𝑟𝑎𝑑𝑖𝑢𝑠 𝑓𝑜𝑟 𝐵𝑒𝑣𝑒𝑙 𝐺𝑒𝑎𝑟 2 𝜔1 = 𝐴𝑛𝑔𝑢𝑙𝑎𝑟 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝐵𝑒𝑣𝑒𝑙 𝐺𝑒𝑎𝑟 1 𝜔2 = 𝐴𝑛𝑔𝑢𝑙𝑎𝑟 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝐵𝑒𝑣𝑒𝑙 𝐺𝑒𝑎𝑟 2
- 9. tan 𝛾1 = 𝑟1 𝑟2 ∗ sin 𝜃 ) − cos 𝜃 ∗ tan 𝛾1 tan 𝛾1 + 𝑟1 𝑟2 ∗ cos 𝜃 ∗ tan 𝛾1 ) = 𝑟1 𝑟2 ∗ sin 𝜃 tan 𝛾1 ∗ 1 + 𝑟1 𝑟2 ∗ cos 𝜃 ) = 𝑟1 𝑟2 ∗ sin 𝜃 tan 𝛾1 = 𝑟1 𝑟2 ∗ sin 𝜃 1 + 𝑟1 𝑟2 ∗ cos 𝜃 tan 𝛾1 = sin 𝜃 𝑟2 𝑟1 + cos 𝜃 tan 𝛾1 = sin 𝜃 𝜔1 𝜔2 + cos 𝜃 tan 𝛾2 = sin 𝜃 𝑟1 𝑟2 + cos 𝜃 tan 𝛾2 = sin 𝜃 𝜔2 𝜔1 + cos 𝜃 𝑎𝑠 𝑟1 𝑟2 = 𝜔2 𝜔1
- 10. 𝐹t1 = 𝐹t2 𝐹r1 = 𝐹x2 𝐹x1 = 𝐹r2 𝐹t1 = 1000 ∗ 𝑃 𝑉 Fx =Axial Force Fr =Radial Force Ft=Tangential Force
- 11. No Type Normal Ratio Range Efficiency Range 1 Spur 1:1 to 6:1 94-98% 2 Straight Bevel 3:2 to 5:1 93-97% 3 Spiral Bevel 3:2 to 4:1 95-99% 4 Worm 5:1 to 75:1 50-90% 5 Hypoid 10:1 to 200:1 80-95% 6 Helical 3:2 to 10:1 94-98% 7 Cycloid 10:1 to 100:1 75% to 85%
- 13. 13 Subject :- Theory of Machines II