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Pic. 14: 1. Pressure spring. 2. Friction lining of the driven disk. 3. Rivet fastening the pressure spring to the clutch housing. 4. Driven disk. 5. Damper thrust pin. 6. Front damper plate. 7. Rear damper plate. 8. Hub of the driven disk. 9. Damper spring. 10. Pressure plate. 11. Flywheel. 12. Clutch housing cover. 13. Clutch housing. 14. Clutch cover. 15. Gearbox front cover. 16. Primary (leading) gearbox shaft. 17. Clutch release bearing. 18. Thrust flange friction ring. 19. Ball joint of the clutch release fork. 20. Clutch release fork spring. 21. Pressure spring support ring. 22. Clutch release fork pusher. 23. Clutch release fork. 24. Working cylinder. 25. Release spring for the clutch release fork. 26. Damper friction ring. 27. Damper support ring. 28. Belleville damper spring. 29. Plate connecting the pressure plate to the clutch cover. 30. Compression spring retainer. 31. Plate connecting thrust flange and clutch cover. 32. Thrust flange. 33. Clutch release bearing. 34. Spring connecting the fork to the clutch release bearing. I - Diagram of damper action.
The car has a classic layout with a front-mounted engine parallel to the longitudinal axis of the car and rear-wheel drive. With this arrangement, the torque from the engine is transmitted to the drive wheels through the following transmission components: clutch, gearbox, driveline and rear axle mechanisms (final drive, differential, axle shafts).
The transmission of cars is characterized by a high degree of unification of parts, mechanisms and assemblies with other models of cars of the Volga Automobile Plant, low labor intensity of maintenance, reliability and durability, consistent with the life of the car before overhaul.
The clutch provides a smooth connection of the flywheel 11 with the primary (leading) shaft 16 of the gearbox when starting the car. In this case, the torque from the crankshaft is smoothly transmitted through the transmission elements to the driving wheels of the car, which ensures smooth starting of the car. At the moment of gear shifting, as well as during braking, the clutch disconnects the engine crankshaft from the transmission, stopping the transmission of torque to the drive wheels, thereby creating conditions for bumpless gear shifting, wear of the wheel brakes and transmission parts is reduced and more efficient braking occurs. Two types of clutch are used on VAZ cars: 2103 and 2121. The first type of clutch is used on cars equipped with engines with a displacement of 1.2; 1.3; 1.5 l, the second type on vehicles with engines with a displacement of 1.6 l. To distinguish the leading parts of the clutch (clutch cover with pressure plate and spring) on clutch 2121, a mark is made in the form of a hole with a diameter of 6 mm, in one of the slots of the pressure spring petal. The driven disks also differ, both in shape and in the width of the friction linings. Clutch type 2103 has a friction lining width of 29 mm, clutch type 2121 has 35 mm and they are riveted with a large number of rivets.
The clutch is single-disc, dry, permanently closed type. The principle of operation is based on the transfer of torque from the flywheel to the input shaft of the gearbox due to the friction forces that occur between the surfaces of the flywheel 11, driven 4 and pressure 10 disks when they are compressed. The driven disc, located on the splines of the input shaft of the gearbox, is clamped between the flywheel and the pressure plate by the force of spring 1. The force must be such as to prevent slipping of the driven disc, otherwise the torque will not be fully transmitted to the drive wheels, and the discs will wear out intensively due to slip.
If the driven disk is connected to the input shaft of the gearbox, then the pressure disk 10, together with the clutch cover 14, is bolted to the flywheel. Thus, some parts have a permanent connection with the flywheel, others are temporary, due to friction forces when the clutch is engaged. The first parts make up the driving part of the clutch, the second part is the driven part. The removal of the pressure plate from the driven, i.e., the clutch is released, is carried out through a hydraulic drive.
The parts that make up the driving and driven parts of the clutch are mounted on the flywheel and covered with a crankcase 13, which is attached to the end of the engine block. A stamped cover 12 is installed between the engine block and the clutch housing, covering the cavity of the clutch housing.
The leading part of the clutch is made as a separate non-separable unit, which includes the clutch cover 14, the pressure plate 10, the central pressure spring 1 and a number of other secondary parts. This assembly is attached to the flywheel with six bolts with spring washers. Precise alignment of the clutch drive on the flywheel is provided by three dowel pins pressed into the flywheel.
The clutch cover is stamped from steel. It has a concave shape, forming a cavity in which the pressure spring and pressure plate are located. Holes for pins and fastening bolts are made on the flanged part of the casing. Inside the casing, one support ring 21 is welded, on which one side of the pressure spring rests. The pressure spring 1 is attached to the clutch casing with rivets 3. The rivets pass through the oval holes of the pressure spring. Another support ring 21 of the pressure spring rests against the heads of these rivets. This hinged connection allows the spring to flex relative to the support rings.
The pressure spring is stamped from spring steel. Radial slots divide its surface into individual petals that act as clutch release levers. Thrust flange 32 acts on these petals, which is pressed against them due to the elasticity of connecting plates 31. Friction ring 18 is glued to the outer surface of the thrust flange.
The outer edge of the pressure spring enters the grooves of the retainers 30, which are riveted to the pressure plate. Through the clamps, when the pressure spring is deflected relative to the support rings 21, the pressure plate is retracted from the driven one.
The pressure plate 10 is cast iron. It has the shape of a ring with three tides. The pressure plate is connected to the clutch cover by three pairs of elastic plates 29, which are riveted at one end to the tides of the pressure disk, and at the other end to the clutch cover. This connection ensures the transmission of torque from the casing 14 to the pressure plate and at the same time the axial movement of the pressure plate inside the clutch casing.
The working surface of the pressure plate is polished. On its annular ledge, 12 ventilation slots are made, which improve the cooling of the disk. Clamps 30 are fastened with rivets in three grooves.
The leading part of the clutch is balanced. Permissible unbalance should not exceed 250 gf mm. Balancing is achieved by drilling metal in the tides of the pressure plate.
The driven part of the clutch consists of a driven disc 4 with friction linings 2 and a torsional vibration damper (damper).
Driven disk - steel; T-shaped radial slots divide it into twelve petals. Each petal has a flat area and two bends (bulges), due to which the surface of the disk has a wavy shape. To maintain this shape, friction linings 2 are riveted to each petal independently of each other, one to the convex part of the petal, the other (opposite) to a flat area. The heads of the rivets are buried in the holes of the linings, and their rods are riveted from the side of the disk. Holes are made in the opposite lining to access the rivets. Such fastening of the pads retains the wave-like shape of the surface of the driven disk, which is necessary for smooth engagement of the clutch, since the driven disk becomes flat gradually, as pressure on its surface increases. In this case, the initially driven disk slips relative to the surfaces of the flywheel and pressure plate, and the transmitted torque increases gradually. This ensures smooth starting of the car and protects transmission parts from overloads.
The driven disk is connected to the hub 8 not rigidly, but elastically through the damper parts. Such an elastic connection provides damping of torsional vibrations that occur in the transmission due to uneven operation of the engine and transmitted dynamic loads.
In the hole of the hub, splines are cut for connection with the splines of the input shaft 16 of the gearbox. The hub flange has six windows and three horseshoe cutouts. Thrust fingers 5 pass through these cutouts, which connect the front 6 and rear 7 damper plates and the driven disk 4. The ends of the thrust fingers are riveted. In the front and rear plates of the damper and in the driven disk, the same windows are made as in the flange of the hub 8. Springs 9 are located in these windows, which are kept from falling out by the flanging of the windows in both damper plates. The springs have different elasticity, which expands the area of the damper. The stiffer springs are painted lighter. They are installed between springs of lesser elasticity.
Friction rings 26 are installed on both sides of the hub flange. The Belleville spring 28 through the support ring 27 creates a constant moment of friction between the surfaces of the friction rings and the hub flange.
In the event of torsional vibrations, with a sharp change in the speed of the vehicle or with a sharp engagement of the clutch, the driven disk moves along with the damper plates relative to the hub 8. In this case, the damper and spring friction element is activated. The resistance they create dampens shock loads and torsional vibrations, protecting transmission parts from breakage and intense wear. The action of the elastic element of the damper is limited by three thrust fingers 5, which abut against the horseshoe cutouts of the hub.
Clutch disengagement, i.e. the removal of the pressure plate from the driven one is carried out through a hydraulic drive controlled by the clutch pedal. The force from the clutch pedal through the hydraulic drive is transmitted to the clutch release fork 23, and from it to the clutch 17 of the clutch release bearing.
The fork 23 rests on the ball bearing 19 and is held on it by a flat or round curly spring 20. The spring is attached to the fork, and the ball bearing is screwed into the threaded hole of the clutch housing. Pusher 22 passes through the outer end of the fork, onto which an adjusting nut and a lock nut are screwed. The fork is pressed against the hemispherical surface of the adjusting nut by spring 25. So that when the spring is disconnected, the fork does not fly off the pusher, a cotter pin is installed at its end. The hatch through which the end of the fork comes out of the crankcase is sealed with a protective cover. The adjusting nut changes the working length of the pusher 22. This changes the gap between the clutch release bearing and the friction ring 18 of the thrust flange, which should be 1.5-2 mm, which corresponds to the free travel of the pusher of the clutch release fork 4-5 mm. To hold the pusher when turning the adjusting nut and locknut, two turnkey flats are made on it.
The clutch 17 of the clutch release bearing is located on the guide sleeve of the front cover 15 of the gearbox. The clutch release bearing 33 is pressed onto the clutch. To the tides of the clutch, the inner end of the clutch release fork is pressed by spring 34.