Design and development of an automotive vertical doors opening system avdos
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    Design and development of an automotive vertical doors opening system avdos Design and development of an automotive vertical doors opening system avdos Document Transcript

    • International Journal of Advanced JOURNAL OF ADVANCED RESEARCH IN INTERNATIONAL Research in Engineering and Technology (IJARET), ISSN 0976 – 6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (IJARET) ENGINEERING AND TECHNOLOGY (2012), © IAEMEISSN 0976 - 6480 (Print)ISSN 0976 - 6499 (Online)Volume 3, Issue 2, July-December (2012), pp. 176-186 IJARET© IAEME: www.iaeme.com/ijaret.aspJournal Impact Factor (2012): 2.7078 (Calculated by GISI) ©IAEMEwww.jifactor.com DESIGN AND DEVELOPMENT OF AN AUTOMOTIVE VERTICAL DOORS OPENING SYSTEM (AVDOS) 2 2 A. Elfasakhany1, 2 *, J. A. Alarcón , D. O. S. Montes 1 Department of Mechanical Engineering, Faculty of Engineering, Taif University, Box 888, Al- Haweiah, Taif, Saudi Arabia 2 Tecnológico de Monterrey, Campus Ciudad Juárez, Av. Tomas Fernandez Campus 8945, Parque Industrial Bermudez, CP 32470, Ciudad Juarez, Chihuahua, Mexico * Corresponding author Tel.: +966 (02) 7272020; Fax: +966(02)7274299 E-mail address: ashr12000@yahoo.com ABSTRACT Automotive vertical door opening system (AVDOS) refers to car or truck door that opens upward instead of outward like conventional cars on the road. Compared with conventional doors, the AVDOS provides easier access to the car in small spaces and, in turn, allows less parking area for cars. The main focus of this work was to propose a new design for the AVDOS. That design overcomes some drawbacks of the available vertical door design. It offers access/egress without the side movement that available design use. It also provides an easier access into a car that is in a tighter spot. It can also be able to open/close the doors without having to hard push or slam the doors. It is safer and less cost. In case of a rollover emergency egress may be easier and more secure than the available design. Keyword: Vertical doors, Design, Mechanism, Gas spring, Gear, Development. I- INTRODUCTION The term vertical doors (or scissor doors) refers to car or truck doors that open upward instead of outward like conventional cars on the road. The most famous companies that use those types of doors are the Italian Lamborghini company, which has become these doors with time bearing its name (Lambo doors) [1-2]. Those types of doors have firstly begun through car Alfa Romeo 176
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEMECarabo in 1968. The idea came to the designer based on that the driver was suffering from lack ofthe possibility to see what behind the car because of wider car design. In order to reverse the car,the driver needs to open the door and lean his upper body out of the hatch in order to see behind.That gave the designer the idea of doors to open up [1]. In 1974, when the same designer workedon a car Lamborghini Countachs successor, the first commercial vehicle made those doors, due tofacing the same problem of poor rear visibility, he designed it using the same idea of doors thatopen up. Currently, Lamborghini is keen to design the majority of such doors [1]. The vertical doors offer many advantages compared with the conventional doors. They offerthe possibility of operating the car during door open, in a manner that would be difficult orimpossible in a car with conventional doors. Because the vertical doors stay within the cars trackthroughout their range of movement, they are useful when parking in tight spaces. The hinges ofAVDOS can be placed in a similar location to the conventional door, so a convertible version ofthe conventional car is possible with the same door style and, in turn, that reduces the dooringhazard to cyclists. However, there are some drawbacks for using the vertical doors. The door stillimpedes access/egress much more than a conventional door. The manufacture cost of the doorhinge can be more than that of a conventional door. It is also important to consider the cost ofrepairing the doors if the mechanisms fail in any way [3]. If the height of the parking lot ceiling isinsufficient, the door may come into contact with it when opened. For example, in case of the carrolling onto its roof, the doors would not be able to open. In the event of a rollover emergencyegress may be more difficult than with conventional doors, if not impossible. In water or insituations such as the car exploding, this can be very dangerous. The lifting mechanism for thedoor could go out, and then the doors would not be able to open at all. According to the many drawbacks of the available vertical doors, this work aims at proposinga new design for the AVDOS. The system overcomes some of the short-comings of existingsystem by allowing larger access for ingress and egress than the available vertical door system.The proposed system can be installed simply and not costly. It can also be able to access/egressthe car without having to hard push or slam the doors. The system can efficiently be an alternativeto the existing hinge mechanism. This work is a part of different projects to design and developdifferent mechanical systems/machines, see e.g. [4-8].II- SYSTEM DESIGN1- Available Design The available design of the automotive vertical door opening system (AVDOS) is workedbased on that it is initially open outward before opening upward. The outward motion allows thetop edge of the door to clear from the door frame [2]. Accordingly, drivers need to push the doortwo times, one horizontal for the outward and then one vertical for the upward opening. TheAVDOS is shown in Fig. 1 and the detailed function is as follows. When inside: you will grab thedoor handle of the car. Pushing the door away from you and the door will open 12 - 18 inches likethey do normally in the conventional doors. From there, the door will stop and not openhorizontally any further. Once done, you will now grab the bottom of the door and lift vertically.The door will then reach a certain point which it will not lift anymore. At this point, the bottomback portion of the door will be higher than the roof of the vehicle, as shown in Fig. 2.Accordingly, you will be able to get out of the vehicle. On the other hand, when you outside the 177
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEMEcar: you will grab the door handle of the car and pulling the door towards you; hence the door willopen slightly (12 - 18 inches) then grab the edge of the door and lift vertically. The door will thenreach a pre-determined point at which it will be able to get in. The second movement of the door(grab the bottom of the door and lift vertically) is difficult and unstable, especially when door isheavy. This makes the mechanism is inefficient and complicated to use. The design allowsopening the door of 15 degrees outwards and then lifts it upwards for 75 to 90 degrees. Fig. 3shows the AVDOS assembled in a car. Fig. 1: Available design of automotive vertical door opening system (AVDOS) for two systems2- Proposed Design The main differences between the proposed design and the available one is that availabledesign requires two movements to open the doors, the first one is horizontal and the secondone is vertical, as discussed early. In some cases, doors are very heavy for the vertical push.However, the proposed design is based on moving the door upwards with only one small pushusing one finger. Generally, the door is mounted using two hinges, where one hinge is mountedonto the post of the car body and the other hinge is mounted onto a parallel door structure, asshown in Fig. 4. This allows the hinges to open the door by swinging away from the vehicle,thereby providing an adequate opening space to get in and out from the vehicle. Hence, ourproposed mechanism is designed based on allowing the automotive door to open without the sidepush that available vertical door does. But, the side movement occurs by the swinging path of themechanism. The proposed AVDOS, as shown in Fig. 4, consists of three main subsystems,mechanism structure (hinges), gears, and gas spring. Detailed of each subsystem is discussed inthe coming sections. 178
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME Fig. 2: Overview of vertical door opened Fig. 3: Available design of AVDOS assembled in car2.1-Mechanism Design Mechanism makeup with detailed dimensions, as shown in Fig 5, is designed to allow theautomotive door moving in a bi-directional i.e., in one or diagonal direction. The dimensions arecalculated based on a door weight of about 110 lb (appropriate for a sports car). The hinges weredesigned based on the shape of automotive doors. Since automobiles and trucks are essentiallyrectangular in shape, the most common method of providing doors is to mount the hinge on aforward vertical edge of the door, allowing the trailing edge of the door to swing easily. Thatgives more advantage for smaller vehicles, which have much smaller exit openings than thelarger vehicles. Hence, such design provides wider opening of the door due to more swingingdoors in this design configuration. 179
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME Mechanism structure (hinges) Gears Hinge mounted Hinge mounted onto the car body onto the door structure Gas spring Fig. 4: Proposed AVDOS2.2-Gas Spring A gas spring is a type of spring that, unlike a typical metal spring, uses a compressed gas,contained in a cylinder and compressed by a piston, to exert a force. Gas spring is more or less tobe some kind of pneumatic striker. It pushes the door away from the car when being opened andvice versa in the closed condition. The gas spring, as a hydropneumatic adjusting element, consists of a pressure tube, a pistonrod with piston and appropriate connection fittings, as shown in Fig. 6. It is filled withcompressed nitrogen, which acts with equal pressure on differently dimensioned cross-sectionalareas of the piston with same pressure in the both sides of piston. This produces a force in theextension direction. This extension force can be defined as follows. P × A = P × ( A − a) + F (1) F = P×a (2)where A and a are the cross section area of the piston and the piston rod, respectively; P and F are pressure andforce, respectively. The extremely high pressure of the nitrogen gas inside cylinder is only applied to the netcross-sectional area of the piston without the piston rod, as shown in Fig. 6, keeping volumetricchanges inside the cylinder small and, in turn, resultant force (F) near constant. This qualitymakes gas springs infinitely useful for providing opening and closing force for door, like movingmechanisms in machines. 180
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July December (2012), © IAEME July-December Fig. 5: Detailed d dimensions of the proposed AVDOS Nitrogen P P F Fig. 6: Working principle of gas spring system 181
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME Unlike a typical metal spring, gas springs provide a constant linear force over a defined stroke,as well as dynamic damping from the integral piston to smooth the action. The absorption ordamping action for gas springs can be in both compression and extension working conditions. In acompression gas spring, the shock absorption or dampening occurs in the compression directionby the compressed gas, as shown in Fig 7. In an extension gas spring, the shock absorption ordampening occurs in the extension direction using oil since oil cannot be compressed, as shown inFig 8. The gas spring locking function is made possible by a special piston-valve system whichcreates a leak-proof separation between the two pressure chambers in the gas spring, as shown inFigs 7-8. With the valve open, this will provide force assist, ensuring user-friendly motionsequences due to its predefined damping characteristics. When the valve is closed, the gas springwill lock with a slight bounce in the desired position. When door reach the extreme openingposition, the gas spring will lock rigidly in the compressed state. By small push, the gas springextends and the valve in the piston will open automatically and release the lock. The gas spring system has many advantages. As system components are not expensive, thecosts of systems are quite low (20 USD) [9]. Moreover, as system is very durable, the cost ofrepair is significantly lower than that of other systems. Gas spring systems are safer thanelectromotive systems because they can work in inflammable environment without causing fire orexplosion (nitrogen is not flammable). Apart from that, overloading in system will only lead tosliding or cessation of operation. Unlike electromotive components, gas spring components do notburn or get overheated when overloaded. The operation of gas spring systems does not producepollutants. The system is light and powerful, lighter than equivalent pneumatic system. The dooris raised with the help of a gas spring, thus opening requires minimum efforts (3-10 lb force,depending on application). Valve Fig. 7: Gas spring system at compression condition 182
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME The design limitations of the gas spring system are summarized as follows. The gas springis filled with high-pressure nitrogen gas. For this reason, it may never be opened, exposed to hightemperatures, mechanically damaged or exposed to forces beyond normal use. Mechanicaldamage, corrosion, colors or impurities can damage the sealing part of the gas spring. The gasspring operates at a temperature between -18 to +60°C. The temperature change affects the outputforce up to approximately 5% for every 15°C of temperature change. The oil viscosity will changeas well.2.3-Gears Gears are ones of the most important parts of any machine or mechanism. The function ofgears here is to convert the movement into a single bi-directional diagonal movement. Theuser only has to push the door in one direction, i.e. vertical push. By such push, the gas springwill be activated and vertically move the hinge; but we need a slight horizontal movement to clearthe door from the door frame. The gears are used to provide that function, as shown in Fig 9. Bymoving the hinge, the gear 2 will rotate and, in turn, the gear 1. Hence, intermediate hinge will tiltoutward from the fixed hinge where fixed hinge is supported in the door frame. The gear typeused is bevel gears, as shown in Fig 10, and the prerequisite calculations and designconsiderations are available elsewhere, see e.g., [10-13]. Valve Fig. 8: Gas spring system at extension condition 183
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEMEIII- TESTING AND VALIDATION The system is tested using the cad system and results proof that the system is reliable. Notonly are our AVDOS easy to install but it is also easy to operate, basically open your door usingone push. Figs. 9, 11, and 12 show the system tests at different operating positions. Intermediate hinge Gear 1 Gear 2 Part of the moving hinge (a) Front View (b) Side View Fig. 9: Gas spring system in (a) front and (b) side views showing the bevel gears 184
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEME Fig. 10: Bevel gears Fig. 11: AVDOS at door closing Fig. 12: AVDOS at door open 185
    • International Journal of Advanced Research in Engineering and Technology (IJARET), ISSN 0976 –6480(Print), ISSN 0976 – 6499(Online) Volume 3, Number 2, July-December (2012), © IAEMEIV- CONCLUSIONS A new design of the automotive vertical door opening system (AVDOS) was proposed. By thenew design, we can overcome some drawbacks of the available design. The proposed designconsists of three main systems, mechanism structure (hinges), gears, and gas spring. The systemswere designed to provide a wider door opening by using more swinging configuration, whichgives more advantage for smaller vehicles since they have much smaller exit openings than thelarger vehicles. Compared the both designs, available one requires two movements to open thedoors (outward and then upwards) and in some cases doors are very heavy for the verticalpush. However, the proposed design is based on moving the door upwards with only one smallpush using one finger. Hence, we will be able to open/close the doors without having to hardpush or slam the doors. Not only are our AVDOS easy to operate but it is also more secure andless cost. Testing and validation of the proposed system at different operating positions is carriedout and results proof that the system is reliable.REFERENCES[1] http://allmobilephoneprices.blogspot.com/2012/01/doors-cars.html[2] http://en.wikipedia.org/wiki/Scissor_doors[3] http://www.ehow.com/about_5455626_dangers-vertical-doors.html[4] A. Elfasakhany, E.Y. Rezola, K.B. Quiñones, R.S. Sánc, Design and Development of a Competitive Low-cost Robot Arm with Four Degrees of Freedom, Modern Mechanical Engineering 1 (2011) 47-55.[5] A. Elfasakhany, J. Hernández, J. C. García, M. Reyes, F. Martell, Design and Development of House-Mobile Security System, Engineering 3 (2011) 1213-1224.[6] Elfasakhany, A. Arrieta, D. M. Ramírez, F. Rodríguez, Design and Development of an Autonomous Trash Sorting System, Global Journal of Pure and Applied Sciences and Technology vol. 01i2 (2011) 56-64.[7] A. Elfasakhany, J. Marquez, E.Y. Rezola, J. Benitez Design and Development of an Economic Autonomous Beverage Cans Crusher, International Journal of Mechanical Engineering and Technology (IJMET) 3 (2012) 107-122.[8] A. Elfasakhany, Improving Performance and Development of Two-Stage Reciprocating Compressors, International Journal of Advanced Research in Engineering and Technology (IJARET) 3 (2012) 119-136.[9] http://www.amazon.com/Taylor-Products-Replacement-Shocks- Boxes/dp/B000MUTFRW[10] N.C. Pandya, Elements of Machine Design. India: Charotar Publishing House. (1981) 713– 735.[11] M.F. Spotts, T.E. Shoup, Design of Machine Elements. India: PHI Learning Private Limited. (2010) 399–426. ISBN 978-81-203-1955-4. Seventh edition, Prentice Hall[12] http://www.explainthatstuff.com/gears.html[13] http://www.engineersedge.com/gear_menu.shtml 186