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Pic. 21: 1. A bolt of fastening of a brake drum and a disk of a wheel. 2. Locating pin. 3. Shaft bearing oil deflector. 4. Brake drum. 5. Cast iron brake drum ring. 6. Rear brake wheel cylinder. 7. Fitting for bleeding the brakes. 8. Ball bearing half shaft. 9. Locking ring of the ball bearing. 10. Rear axle beam flange. 11. Half shaft seal. 12. Suspension spring support cup. 13. Rear axle beam. 14. Bracket for fastening the upper longitudinal suspension rod. 15. Axle guide. 16. Differential bearing adjusting nut. 17. Differential bearing. 18. Differential bearing cap. 19. Breather. 20. Satellite. 21. Gear wheel of the main gear. 22. Left axle. 23. Half shaft gear. 24. Rear axle gear case. 25. Gear adjusting ring. 26. Bearing spacer. 27. Gear bearings. 28. Gear seal. 29. Dirt deflector. 30. Gear flange. 31. Flange fastening nut. 32. Oil deflector. 33. Gear wheel of the main transfer. 34. The axis of the satellites. 35. Support washer of the gear wheel of the axle shaft. 36. Differential box. 37. Right half shaft. 38. Brackets for fastening suspension parts. 39. A plate of fastening of the bearing of a semiaxis. 40. Brake shield. 41. Brake shoe. 42. Brake pad. 43. Half shaft flange. 44. Bearing nut retainer plate. 45. A bolt of fastening of a cover of the bearing.
The torque from the driveline is transmitted to the driving wheels of the car through the main gear, differential and axle shafts. These mechanisms are installed in the rear axle of the vehicle, which consists of two basic parts: beam 13 and crankcase 24 of the rear axle gearbox.
The main gear changes the magnitude and direction of the transmitted torque. At the same time, the traction force on the drive wheels increases in accordance with the gear ratio of the final drive. The differential allows the driving wheels of the car to rotate at different speeds, which eliminates the slippage of one of the wheels when the car is turning or when the car is driving on an uneven section of the road when the wheels travel a path of different lengths.
The rear axle of the car is unified with other models of VAZ cars (with the exception of the all-wheel drive vehicle VAZ-2121). Between themselves, the rear axles are distinguished by gearboxes, in which the main gears have different gear ratios. To distinguish the gearboxes, a marking is applied on their neck: U gear ratio 4.44 (For "Universal"); 2 - gear ratio 4.1 for the VAZ 2121 model; without marking - gear ratio 4.3; 3 gear ratio 4.1; 6 gear ratio - 3.9.
On VAZ-2104, 2105 vehicles, the main gear with a gear ratio of 4.1 is used.
Beam 13 of the rear axle consists of two stamped casings welded with longitudinal seams. Two steel flanges 10 are welded to the ends of the casings, in which sockets for bearings 8 and seals 11 of the axle shafts are machined. From the end in the flanges, holes are made for the bolts for fastening the shields 40 and the brake mechanisms of the wheels. The same bolts with nuts fasten the oil deflector 3 and the plate 39, which holds the axle shaft bearing in the flange socket. The half shaft bearing mounting plate and the oil deflector are interconnected by screws through a sealing gasket.
At the ends of the rear axle beam, support cups of the rear suspension springs and brackets for attaching suspension rods and shock absorbers are welded. In the middle part, the beam is widened and has a through opening, to the rear side of which a stamped cover is welded with a low-loading tank located in it (at the same time as control) hole closed with a stopper.
The crankcase 24 of the rear axle gearbox is bolted to the front machined end of the opening. A breather 19 with a spring-loaded valve is screwed into the beam from above. Through the breather, the beam cavity communicates with the atmosphere, which eliminates the increase in pressure in the beam cavity and the ingress of water and dirt into the rear axle when overcoming water barriers.
Guides of 15 axle shafts are welded inside the beam, facilitating the installation of axle shafts when assembling the rear axle. An oil drain hole is located at the bottom of the beam. It is closed with a cork with a magnet.
The main gear consists of a pair of bevel gears 33 and 21, the gear ratio of which is 4.1 (number of teeth at the gear wheel 21 41, at the pinion 33 10). Gears have hypoid gearing, in which the axis of the drive gear 33 is offset relative to the axis of the gear wheel 21, i.e., their axes do not intersect, but cross.
These gears have a complex tooth shape that allows multiple teeth to mesh simultaneously and smoothly. This reduces the load on each tooth, increases the durability of the final drive and allows more torque to be transmitted. However, such a transmission requires special oil (TAD-17 and or similar) with anti-seize additives. Due to the mixing of the gear axis down, the height of the driveline and the floor of the body is reduced. This created a more comfortable accommodation for passengers in the body and partially shifted down the center of gravity of the car, which increased its stability.
The gear 33 is mounted on two tapered roller bearings 27, between the inner rings of which there is a spacer sleeve 26. An adjusting ring 25 is installed between the inner bearing and the end face of the gear, the thickness of which is in the range from 2.55 to 3.35 mm every 0.05 mm Seventeen sizes of the adjusting ring allow you to adjust the relative position of the pinion and the gear wheel with great accuracy, ensuring the correct engagement of the gear wheels.
A flange 30 is put on the splined end of the gear 33, a flange 30 is mounted on the gear with a self-locking nut 31. The working edge of the stuffing box 28 is pressed against the cylindrical surface of the flange. To protect the stuffing box from damage, a dirt deflector 29 is pressed onto the flange. oil pressure seal.
In order to limit the axial movement of the drive gear under operating loads and ensure silent and durable operation of the final drive, the bearings 27 of the gear are preloaded. It is adjusted by tightening the nut 31 to a certain deformation of the spacer sleeve 26. The preload is determined by the moment of resistance to turning the gear.
The gear wheel 21 is made in the form of a ring gear, which is attached to the flange of the differential box with eight self-locking bolts. Together with the differential box, the gear wheel rotates in two tapered roller bearings 17. They are installed in detachable housings of the crankcase 24, which have detachable covers 18. The preload in the bearings of the differential box, as well as the side clearance in the engagement of the main gear gears, is regulated by nuts 16. Position nuts is fixed with a plate 44, which is bolted to the bearing cover 18.
The principle of adjusting the gap in the gear engagement of the main gear is as follows. After adjusting the preload in the bearings of the drive gear, the differential box assembly is installed in the gearbox housing, the adjusting nuts 16 are screwed until they come into contact with the bearing rings and the covers 18 are fixed with a torque wrench with a torque of 5.2 kgf·m. Then, using a special device with indicators, the lateral clearance between the teeth of the drive gear 33 and the gear wheel 21 is adjusted, for which, by turning the adjusting nuts 16, the differential is moved along its axis.
The gap is measured with a fixture indicator and should be 0.08-0.13 mm. After that, the nuts 16 are sequentially and evenly tightened and, according to the divergence of the covers 18 (measured by the second fixture indicator) set the preload in the differential bearings.
The differential is conical two-satellite. It consists of two satellites 20 located on a common axis 34, two gear wheels 23 of the axle shafts and a differential box. The axle is located in the holes of the differential box and is kept from falling out by the gear wheel 21, which covers the hole in the box. Spiral grooves are made in the places where satellites are installed on the axle for better lubrication of the working surfaces of the axle and satellites. The hemispherical surface of the satellites rests on the hemisphere of the differential box.
The satellites are in constant engagement with gear wheels 23, the cylindrical belts of which go into the holes of the differential box and are their supports. Support washers 35 are installed between the ends of the gear wheels of the semi-axes and the differential box, which are produced in different thicknesses. By selecting them in thickness, a gap is established (0-0.1mm) between the teeth of the satellites and the gear wheels of the axle shafts.
Half shafts 37 transmit torque from the differential to the drive wheels. The axle shaft is made integral with the flange, to which 1 brake drum and the rear wheel disc are bolted. In addition, the drum is attached to the axle shaft flange with locating pins 2, which facilitate the removal and installation of wheel disks. To prevent corrosion of the drum "took a liking" to the flange of the axle shaft, during assembly, the landing belt of the axle shaft and its end adjacent to the drum are covered with graphite grease.
The inner end of the axle shaft is connected by splines to the gear wheel 23 of the axle shaft, which is a support for the inner end of the axle shaft. Outside, the axle shaft rests on a ball bearing 8, which is clamped on the axle shaft between its shoulder and the locking ring 9. The ring is pressed onto the axle shaft in a state heated to 300°C.
The axle shaft bearing is sealed on the inside with an oil seal 11, on the outside with a rubber ring, which is installed between the brake shield and the flange of the rear axle beam.
The bearing is mounted in the nest of the rear axle beam by plate 39, which, together with the oil deflector 3 and the brake shield 40, is attached to the end of the rear axle beam. In order to reduce the likelihood of oil getting into the brake mechanism of the rear wheel if the oil seal 11 is damaged, grooves are made on the axle shaft and an oil deflector 3 is installed.
For access to the nuts of the bolts of the oil deflector 3, shield 40 and plate 39, there are two holes in the axle shaft for passing the socket wrench.
Due to the wear of the parts of the rear axle mechanisms, the gaps in the meshing of the gears and other mating parts are violated. This leads to malfunctions in the main gear, differential and axle shafts, determined by the nature of the noise and the place of its occurrence. So, when the axle bearing is worn or destroyed, especially when the axle shaft housing is deformed, noise will constantly come from the rear wheel area when the car moves. From the side of the rear axle gearbox, noise occurs when the car is moving if the bearings of the main gear and differential gear are damaged or worn, the gears or splined joints of the axle shafts are worn.
Noises that are well audible when turning the car occur when parts of the differential are damaged or worn.
If knocks are heard at the beginning of the car’s movement, then their causes may be increased gaps in the spline connection of the gear or in the gearing of the main gear gears and the large wear of the holes for the axis of the satellites in the differential box.
Maintenance of the rear axle mechanisms is reduced to a minimum and includes checking the level and changing the oil in the rear axle beam.