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Pic. 19. Cardan transmission.
1. Gearbox; 2. Front flange flexible coupling; 3. Elastic coupling; 4. Rear flange flexible coupling; 5. Front propeller shaft; 6. Cardan shaft support; 7. Front universal joint; 8. Rear driveshaft; 9. Rear universal joint; 10. Rear axle; 11. Driving wheel of the car; 12. Pillow support; 13. Support bearing housing; 14. Cardan shaft bearing; 15. Support bracket; 16. Cross member of the intermediate support; 17. Distance sleeve; 18. Rubber bushing; 19. Retaining ring needle bearing; 20. Needle bearing; 21. Needle bearing seal; 22. Universal joint cross; 23. Cardan yoke; 24. Nut for fastening the universal joint fork; 25. Flange-fork of the cardan joint; 26. Balancing plate; 27. Front propeller shaft safety bracket; 28. Gland clip; 29. Plug holes for lubrication of splines; 30. Elastic element of an elastic coupling; 31. Metal insert of an elastic coupling; 32. The secondary shaft of the gearbox; 33. Nut; 34. Centering ring seal; 35. Bolts for fastening the elastic coupling; 36. Centering ring; 37. Centering sleeve; 38. Retaining ring; 39. Oil seal; 40. Splined shank of the front propeller shaft; I. Scheme of cardan transmission; II. Cardan joint.
1. Gearbox; 2. Front flange flexible coupling; 3. Elastic coupling; 4. Rear flange flexible coupling; 5. Front propeller shaft; 6. Cardan shaft support; 7. Front universal joint; 8. Rear driveshaft; 9. Rear universal joint; 10. Rear axle; 11. Driving wheel of the car; 12. Pillow support; 13. Support bearing housing; 14. Cardan shaft bearing; 15. Support bracket; 16. Cross member of the intermediate support; 17. Distance sleeve; 18. Rubber bushing; 19. Retaining ring needle bearing; 20. Needle bearing; 21. Needle bearing seal; 22. Universal joint cross; 23. Cardan yoke; 24. Nut for fastening the universal joint fork; 25. Flange-fork of the cardan joint; 26. Balancing plate; 27. Front propeller shaft safety bracket; 28. Gland clip; 29. Plug holes for lubrication of splines; 30. Elastic element of an elastic coupling; 31. Metal insert of an elastic coupling; 32. The secondary shaft of the gearbox; 33. Nut; 34. Centering ring seal; 35. Bolts for fastening the elastic coupling; 36. Centering ring; 37. Centering sleeve; 38. Retaining ring; 39. Oil seal; 40. Splined shank of the front propeller shaft; I. Scheme of cardan transmission; II. Cardan joint.
The torque from the secondary shaft of the gearbox to the mechanisms of the rear axle is transmitted by a driveline, which operates under conditions of a changing angle of torque transmission due to the elastic suspension of the rear axle. At the same time, the distance between the fixed gearbox and the oscillating rear axle also changes. Therefore, in the cardan transmission there are elements that shorten or lengthen it, as well as break at a certain angle. Such elements are: a spline connection of an elastic coupling 3 and three cardan joints - two rigid 7 and 9, one elastic 3.
The cardan gear is two-shaft with an intermediate support 6, which significantly reduces its vibration and runout. Between themselves and the main gear gear, the cardan shafts are connected by rigid cardan joints 7 and 9, and with the secondary shaft of the gearbox - by an elastic joint (clutch) 3. The elastic coupling greatly reduces the noise and vibration of the driveline, and allows torque transmission at an angle. The clutch consists of six rubber elements 30, between which there are metal inserts 31. The elastic rubber elements of the clutch are vulcanized to the inserts and form a single whole. The elastic coupling is located between two flanges 2 and 4, which are connected to the coupling by bolts 35. In this case, the protrusions of the liners go into the grooves of the flanges, centering the elastic coupling on the flanges. Self-locking nuts with nylon inserts are screwed onto the coupling mounting bolts.
To ensure backlash-free connection of the coupling with the flanges and create a constant tightness in the mounting bolts, the holes in the elastic coupling for the mounting bolts are made from the center at a larger diameter than in the flanges. Therefore, before connecting the coupling to the flanges, it is compressed with a special clamp until the holes in the coupling and flanges match, and then the fastening bolts are installed. The same clamp is also used when removing the clutch.
The front cardan shaft 5 is made of a thin-walled pipe, to the ends of which splined tips are welded. On the splines of the front tip 40 is the flange 4 of the elastic coupling. The rear tip rests on the ball bearing 14 of the intermediate support 6. The bearing is located in the steel housing 13 and is fixed in it with a retaining ring. On the shaft, the bearing is clamped by a nut 24 between the shoulder of the tip and the yoke 23 of the cardan joint. The bearing is of a closed type, with seals that securely retain the lubricant incorporated during assembly. Additionally, the bearing is protected by two dirt deflectors. To absorb vibrations of the driveline, the bearing housing is located in a rubber cushion 12, which is vulcanized to the metal surfaces of the bearing housing 13 and the bracket 15 of the intermediate support. The cushion configuration is such that the front driveshaft can have some axial movement. Bracket 15 of the intermediate support is attached to the cross member with two bolts and nuts, and the cross member of the intermediate support is fixed on two bolts welded to the floor of the body. Metal spacer bushings 17 and rubber bushings 18 are installed on the fastening bolts, which isolate the cross member from the floor of the body.
For the safety of the car, a safety bracket 27 is installed under the front propeller shaft, which prevents the shaft from falling when the elastic coupling is destroyed.
The rear propeller shaft 8 differs in its design from the front propeller shaft in that not tips, but forks of universal joints are welded to the ends of the shaft tube. With the help of universal joints, the rear propeller shaft is connected at one end to the front propeller shaft, and at the other end to the final drive gear.
The universal joint consists of two forks 23, a cross 22, four needle bearings 20, oil seals 21 and circlips 19.
The cross connects two forks pivotally; at the same time, the spikes of the cross come into the holes of the forks. Needle bearings are installed on the spikes, the bodies of which are pressed into the holes of the forks with a force of 8000 N (800 kgf). During assembly, the bearings are lubricated with FIOL-2U grease. To hold the lubricant in the needle bearings and seal them, a steel cage is pressed onto each spike of the cross, in which the oil seal 21 is located. It seals the cavity of the needle bearing. Bearing housings are held in the holes of the forks by retaining rings 19. These rings are available in five sizes in thickness. By selecting the rings by thickness, the axial clearance of the cross is set within 0.1-0.4 mm. This gap is needed to center the cross in the forks.
Each ring is painted in its own color. The color of the ring depends on the thickness: the 1.62 mm thick ring is yellow, 1.59 is black, 1.56 is blue, 1.53 is dark brown, 1.50 is natural. The selection of retaining rings is carried out using a special caliber, which has four probes with a thickness of 1.53; 1.56; 1.59 and 1.62 mm.