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1. Half shaft. 2. A bolt of fastening of a brake drum and a wheel. 3. Guide pin. 4. Oil deflector. 5. Brake drum. 6. Axle bearing. 7. Locking ring. 8. rear axle beam flange. 9. Oil seal. 10. Rear axle beam. 11. Thrust plate. 12. Rear brake shield. 13. Axle flange. 14. Axle guide. 15. Differential box bearing adjusting nut. 16. Differential box bearing. 17. Bolt of fastening of a cover of the bearing. 18. Differential box bearing cap. 19. Breather. 20. Beam cover. 21. Differential satellite. 22. Driven gear of the final drive. 23. Axle gear. 24. Adjusting ring of the drive gear. 25. Window for supplying grease to the bearings. 26. Spacer sleeve. 27. Front pinion bearing. 28. Oil seal. 29. Dirt deflector. 30. Flange for fastening the cardan shaft. 31. Flange fastening nut. 32. Oil deflector. 33. Rear axle gear case. 34. Rear bearing drive gear. 35. Main gear drive. 36. The axis of the satellites. 37. Support adjusting washer of the axle gear. 38. Differential box. 39. Laying of the crankcase of the rear axle gearbox. 40. Cork. 41. Bolt. 42. A bolt of fastening of a lock bracket. 43. Locking bracket. 44. Magnetic stopper. 45. Rear axle beam flange reinforcement.
Rear axle - leading, provides torque transmission to the wheels. The gear differential allows the drive wheels to rotate at different speeds, this eliminates the slippage of one of the wheels when cornering relative to the road, when the right and left wheels travel an unequal path.
The rear axle of the car consists of the following main parts: stamped welded beam; reduction gear with hypoid gears of the final drive, the drive gear of which is mounted on two tapered roller bearings and connected to the driveline; differential, consisting of a box mounted on two tapered roller bearings, axle gears, satellite bevel gears and a pin; semi-axes of a semi-unloaded type, to the flanges of which wheels and brake drums are attached.
The axle shaft is supported by a ball bearing of a closed type, installed in the flange of the rear axle beam, and the gear wheel of the differential axle shafts.
Beam 10 of the rear axle consists of two casings stamped from steel sheet 3.5 mm thick, welded with longitudinal seams. Two steel flanges 8 are welded to the ends of the beam, in which sockets are bored for installing bearings 6 and seals 9 of the axle shafts and holes are made for attaching brake shields 12. Support cups of the rear suspension springs, brackets for attaching suspension parts - upper longitudinal rods, shock absorbers, lower longitudinal rods and a transverse rod are welded to the beam. The middle part of the beam has been expanded to accommodate the final drive gearbox. The flange to which the crankcase 33 of the main gear is attached is reinforced with pads 45 welded by relief welding. At the rear, the expanded part of the beam is closed by a welded stamped cover 20 with an oil filling hole closed by a plug 40. An oil drain hole is located in the expanded part of the lower casing of the beam, closed by a magnetic plug 44. A breather 19 is installed in the expanded part of the upper casing of the beam, which connects the internal cavity of the crankcase with the atmosphere for prevent increased pressure inside the crankcase when it is heated during operation, since an increase in pressure inside the crankcase can lead to oil leaking out through the seals.
The gearbox housing, in which the main gear and differential are mounted, is inserted and bolted into the hole of the expanded part of the beam.
The gearbox can be removed from the vehicle without disconnecting the entire axle (pulling out the axle shaft).
Before assembly, the threads of the gearbox mounting bolts are cleaned of oil and dirt and covered with a special sealant, which also prevents the bolts from loosening.
main gear (hypoid) - this is a transmission by bevel gears, the axes of rotation of which intersect. The gear teeth of such a transmission have a complex shape, and an increased number of teeth are in simultaneous engagement. Simultaneous engagement of several pairs of teeth (thanks to overlap) reduces the load acting on each tooth, which increases the margin of safety of the teeth of the hypoid final drive.
The hypoid gear has a smaller running-in of the working surfaces of the teeth and, in terms of kinematics, approaches the worm gear, in which the engagement of the teeth is characterized by an increased slip of their working surfaces.
These properties of the hypoid gear increase the smoothness of the gearing and reduce the noise of the rear axle, but require the use of a special oil with extreme pressure properties. For VAZ vehicles, TAd-17i oil is used.
In addition, the displacement of the axes of the drive and driven gears reduces the height of the driveline, and hence the floor of the body.
At the factory, final drive gears are selected for noise and meshing contact. Therefore, if it is necessary to replace one of the gears, both are replaced.
The final drive gears are mounted in the gearbox on tapered roller bearings with adjusted preload to ensure their quiet and durable operation. The necessary preload of the bearings 27 and 34 of the drive gear 35 is provided by tightening the self-locking nut 31 and the corresponding deformation of the spacer sleeve 26 installed between the inner rings of the bearings. Nut 31 is tightened with a torque of 12–26 kgf·m until the moment of resistance to turning over the drive gear is 0.16–0.20 kgf·m for new bearings or 0.04–0.06 kgf·m for bearings after mileage of 30 km or more.
The correct position of the drive gear relative to the driven gear is ensured by selecting the thickness of the adjusting ring 24, placed between the support end of the drive gear and the inner ring of the rear bearing. The ring is selected such a thickness at which the gear is set to the nominal position.
To seal the crankcase of the final drive gearbox, a rubber self-clamping gland 28 is pressed into the front neck of the gearbox, which has a second protective edge in addition to the working edge. The stuffing box works on the polished cylindrical surface of the flange 30. To discard oil from the stuffing box, an oil deflector 32 is installed between the driveshaft mounting flange and the front bearing. Outside, the stuffing box is protected by a dirt deflector 29 pressed onto the flange.
The driven gear 22 is attached to the flange of the differential box with eight self-locking bolts 41. Together with the differential box, the driven gear rotates in two tapered roller bearings 16 installed in the final drive housing. The seats of these bearings have covers, each of which is fastened with two bolts 17 with spring washers. Detachable supports allow you to remove the differential from the gearbox housing together with the driven gear. The required position of the driven gear, i.e. the required value of the side clearance, is set by adjusting nuts 15. The preload of the bearings of the differential box is adjusted with the same nuts. The required preload is set when the camber of the bearing caps has reached the required value. In the desired position, the adjusting nuts are locked with locking brackets 43, the protrusions of which fit into the grooves of the adjusting nuts. The brackets are attached to the covers with bolts 42 with spring washers.
The differential is conical, with two satellites 21, put on a common axle 36. The satellites are supported by spherical ends on the spherical surface of the differential box.
Axle 36 is inserted into the differential box and is kept from falling out by the main gear driven gear, which blocks the axle holes in the box. For better lubrication of the rotating satellites, spiral grooves are made on the axis.
The gears of the 23 axle shafts are centered in the cylindrical sockets of the box, and the ends are supported by bronze washers 37. The axial clearance of the gear of the axle shafts is regulated by the selection of these washers in thickness.
Axles 1 of the rear axle are forged from carbon steel together with flanges 13, to which brake drums and wheels are attached with four bolts 2. The splined ends of the semi-axes enter the slotted holes in the gears of the semi-axes.
Bearings 6 semi-axes ball, closed type with seals. On the axle shaft, the bearing is fixed with a locking ring 7, seated on the axle shaft in a hot state. The outer ring of the bearing is installed in the socket of the flange 8 of the rear axle beam and secured with a plate 11 screwed to the flange 8 with four bolts.
Between the plate 11 and the flange 8 there is a stamped brake shield 12 with a rear brake mounted on it.
To seal the cavity of the rear axle on the inside of the bearing 6, behind the locking ring 7, a rubber self-clamping gland 9 of the axle shaft is installed. Oil deflector 4 and grooves on the axle shaft serve to protect the brake pads from oil ingress if it leaks out if the bearing and stuffing box seals are broken.