2. Vakili. Dr Behnam sadri (865211018) Babak vajdi (865211032) Atta sojoodi (865211012) Mehdi jebeli 845222017 Navid khakpay (865211007) Nima shamsapour (865211015) Mechanical Engineering Design

3. : Contents Preface ……………………………………4 What is a gearbox?………………………5 Project description………………………..7 Bulky characteristics of gearbox………..8 Gear design……………………………….9 Shaft design………………………………34 Deflection consideration…………………37 Bearing selection…………………………41 Computer programming…………………54 Acknowledgments………………………..55 References………………………………..56

4. Preface: The present work is a class project of mechanical engineering design on Samand’s gearbox. The quad did as much as possible in order to analyze,collect, calculate and present the results. At first we have a historical vision on gearbox then all the parts of gearbox’s evaluations (some with more details) will be considered. we have utilized some CAD soft wares like ANSYS,solidworks, catia &Mdesign and the programming is MATLAB language. We are really grateful of Dr.vakili on behalf of the recommendations and hope to satisfy him about the process.

5. ? What is a gearbox Gears are about as old as any of the machinery of mankind. The oldest machine is the potter's wheel. At first time over 3000 years ago primitive gears first meshed with each other and transmitted rotary motion. Water wheels were used to convert energy of moving water into energy that would power machines. Wooden gears connected water wheels to machines that would grind wheat and hammer metals. A transmission or gear box provides speed and torque conversion and from a rotating power source to another device using gear ratios. In British English the term TRANSMISSION refers to the whole drive train, including gearbox, clutch, prop shaft,( for rear wheel drive), differential and final drive shafts. The most common use is in drive shafts. The most common use is in motor vehicals,where the transmission motor vehicals,where the transmission adapts the out put of the internal combustion engine to the drive wheels. engine to the drive wheels.

6. Often, a transmission will have multiple gear ratios (or simply multiple gear ratios (or simply "gears"), with the ability to switch between them as speed varies. This switching may be done manually (by the operator), or automatically. Directional (forward and reverse) control may also be and reverse) control may also be provided. Single-ratio transmissions also exist, which simply change the speed and torque (and sometimes direction) of motor output. Gearboxes have found use in a wide variety of different—often stationary—applications, such as wind turbines. stationary wind turbines stationary wind turbines Transmissions are also used in agricultural, industrial, construction, mining and automotive equipment. In addition to ordinary transmission equipped with gears, such equipment makes extensive use of the hydrostatic drive and electrical adjustable- speed drives. agriculturalindustrial constructionmining automotivehydrostatic driveadjustable- speed drives agriculturalindustrial constructionmining automotivehydrostatic driveadjustable- speed drives

7. Project description It is desired to design a gearbox To get this we first anaylzed It is desired to design a gearbox To get this we first anaylzed the forces and power generated in the internal combustion engine then according to the inpute data like the maximum torque and maximum power gears designed Then by considering the shasfts distans and gears diameters the critical gear mated during the engaging identified Then all diameters of shafts were found out It is important to note that we used some steps through the shafts inorder to reduce the material used in manufacturing At last all the bearings were selected for the most critical condition and all the data and informations were wrote besides.the figures

8. Bulky characteristics of gearbox 39.15Kg Total weight 420mm length 240mm width 310mm height 0.0312m^3 Occupied volume 195$ Approximate cost 150(mm) Normal distance of shafts 360mmUpper shaft length 410mmLower shaft length 40mmDistance of gear 5,4 5mmDistance of gear 4,3 20mmDistance of gear 3,2 5mmDistance of gear 2,REV 60mmDistance of gear REV,1

9. Gear design There are some important notes to be informed. First we calculated the power generated,from some principle physics and fluid mechanics. During the engaging of the gears to the higher speeds, the power increases and the torque reduces. For the rear gear we assumed the conditions as well as 1 stt gear,inorder to have the worst situation. the assumption for the overload factor was according to the speed of the shaft. when we have low speeds it should be less than 1.5 and when the speed increases,the unbalanced forces increases and the overload factor shouldn’t be less than 2.The gear strength for live assumed 10^8 cycles & the reliability was set 99%.Temperture factor was not considered. The surface condition factor was almost 1 because of our gear materials. All the gears are from steel but different hard nesses.

10. Gear1(pinion): 2.5 MnMnMnMn 70mmD 24N 40mmF St,grade2,550HBMaterial 3000rpmW64.5hpH 13128N W t *n d 20n 30 1 KoKoKoKo1.2 SFSFSFSF 1.2 SHSHSHSH 8 QvQvQvQv

11. (more details)

12. Gear1(gear): 2.5 MnMnMnMn 230mmD 80N 40mmF St,grade2,550HBMaterial 913rpmW64.5hpH 13128N W t *n d 20n 30 1 KoKoKoKo1.4 SFSFSFSF 1.3 SHSHSHSH 8 QvQvQvQv

13. (more details)

14. Rear gear (pinion): 2.5 MnMnMnMn 70mmD 28N 40mmF St,grade2 Carburized & hardened Material 3000rpmW64.5hpH 13128N W t *n d 20n 0 1.25 KoKoKoKo1.5 SFSFSFSF 1.2 SHSHSHSH 8 QvQvQvQv

15. (more details):

16. Rear gear (gear): 2.5 MnMnMnMn 230mmD 92N 40mmF St,grade2 Carburized & hardened Material 913rpmW64.5hpH 13128N W t *n d 20n 0 1.25 KoKoKoKo1.02 SFSFSFSF 1.1 SHSHSHSH 8 QvQvQvQv

17. (More details)

18. 2 nd gear (pinion): 3700rpmW 70hpH 7700N W t *n d 20n 30 4 MnMnMnMn105mmD 22N 40mmF St,grade2 Carburized & hardened Material 1.5 KoKoKoKo2 SFSFSFSF 1.2 SHSHSHSH 8 QvQvQvQv

19. (more details)

20. 2 nd gear (gear): 4 MnMnMnMn 195mmD 42N 40mmF St,grade2 Carburized & hardened Material 2000rpmW70hpH 7700N W t *n d 20n 30 1.5 KoKoKoKo2 SFSFSFSF 1.2 SHSHSHSH 8 QvQvQvQv

21. (More details)

22. 3 rd gear (pinion): 4 MnMnMnMn 130mmD 30N 30mmF St,grade2450HBMaterial 4500rpmW80hpH 5845N W t *n d 20n 30 1.5 KoKoKoKo2 SFSFSFSF 1.12 SHSHSHSH 9 QvQvQvQv

23. (more details)

24. 3 rd gear (gear): 4 MnMnMnMn 170mmD 40N 30mmF St,grade2450HBMaterial 3440rpmW80hpH 5845N W t *n d 20n 30 1.5 KoKoKoKo2 SFSFSFSF 1.12 SHSHSHSH 9 QvQvQvQv

25. (more details)

26. 4 th gear (pinion): 4 MnMnMnMn 152mmD 33N 30mmF St,grade1300HBMaterial 5300rpmW90hpH 4775N W t *n d 20n 30 2 KoKoKoKo1.1 SFSFSFSF 2 SHSHSHSH 9 QvQvQvQv

27. (More details)

28. 4 th gear (gear) 4 MnMnMnMn 148mmD 32N 30mmF St,grade1300HBMaterial 5443rpmW90hpH 4775N W t *n d 20n 30 2 KoKoKoKo1.1 SFSFSFSF 2 SHSHSHSH 9 QvQvQvQv

29. (More details)

30. 5 th gear (pinion) 4 MnMnMnMn 172mmD 38N 20mmF St,grade1350HBMaterial 6000rpmW100hpH 4140N W t *n d 20n 30 2 KoKoKoKo1.1 SFSFSFSF 2.5 SHSHSHSH 9-10 QvQvQvQv

31. (More details)

32. 5 th gear (gear) 8062rpmW 100hpH 4140N W t *n d 20n 30 4 MnMnMnMn128mmD 28N 20mmF St,grade1350HBMaterial 2.5 KoKoKoKo1.1 SFSFSFSF 2.5 SHSHSHSH 9-10 QvQvQvQv

33. (More details)

34. Shaft design: Now it is the time to design the shafts. The most important note is the gears weight. For the upper shaft, we assumed concentrated weight at the center of the gears but at the lower shaft because of their large size, we assumed uniform distributed force. The other note is the steps. During the calculation, we saw that there are some parts that can be manufactured with less diameters. saw we considered some steps and used 3mm fillet radius. The fatigue failure was one of the important factor. this is stated after evaluating the other parameters like critical frequency and defelction.the SODERBERG was the relation for the fatigue failure. The deflection would result in larger diameters, so we used one more bearing in each shaft to reduce the deflection. The calculations resulted in the critical condition when engaging the rear or the 1 st gear. so we examined the gear 4 in order to reject it as the bad condition then we solved the problem on the base of rear and 1 st gear.

35. Upper shaft: 36mm50mm45mm Diameters from left to right 1030HR Material Critical situation is when rear gear is engaged.

36. Lower shaft: 50mm47mm34mm Diameters from left to right 1045 CD Material Critical situation is when rear gear is engaged

37. Deflection considerations(ANSYS) Other gears just vanished. Modeling

38. Showing the fillets of the steps. Uniform load distribution of the gear.

39. Stress distribution. (before middle bearing) Stress distribution. (after middle bearing)

40. Stress distribution. (after middle bearing) Stress distribution. (after middle bearing)

41. Bearing selection: We were supposed to select 4 bearings,two for the upper shaft and two for the lower shaft. But when evaluating the deflections we saw that it is worth to try the 3 rd bearing for each shaft and reduce the undesirable deflection which can cause force increased during the engaging. So we did it and According to the critical forces, we selected the suitable bearing from SKF online bearing selection for a long life.Ofcourse in bearing selection, its diameters,mass and cost were considered According to the critical forces, we selected the suitable bearing from SKF online bearing selection for a long life.Ofcourse in bearing selection, its diameters,mass and cost were considered.

42. Upper shaft (right side):

44. Upper shaft (Left side):

46. Upper shaft (middle)

48. Lower shaft( right side)

50. Lower shaft( left side)

52. Lower shaft (middle)

54. Computer programming: In order to computerize the evaluations,we wrote the program which gets some input data like m,Np,Ng,Wt,speed and some others and predicts the coefficient of safety for pitting and bending.Ofcourse we are really grateful of Mr.milanchiyan for his prior program which we have extended it.There is an animation which shows the operation.

55. Acknowledgment: At first we really thanks GOD which provided the conditions in order to work on the project as much as possible. Then we are really grateful of our wise master,Dr.vakili on behalf of the recommendations. We really thanks from TAKARAN CO(ISACO bureau in TEHARAN), our dear engineer,Mr.Ghorbani and our classmate Mr.milanchiyan.We hope to develop our performance in future works.enshalah….

56. References: 1.Budynas,Nisbett,shigley’s mechanical engineering design,6 th,7 th,8 th edition,Mc graw Hill, 2.دکتر محمد رحیمیان،تحلیل و طراحی توسط نرم افزار ANSYS 3.طراحی در ANSYS،نیما جمشیدی،مجموعه کتابهای مثلث نارنجی 4.www.SKF.COM

57. The Group: