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Figure 23. Front suspension strut: 1. Compression valve body; 2 Compression valve discs; 3. Compression valve throttle disc; 4. Compression valve plate; 5. Compression valve spring; 6 Compression valve cage; 7. Recoil valve nut; 8 Recoil valve spring; 9. Recoil valve plate; 10 Washer Nut; 11. Recoil valve disc; 12. Recoil valve throttle disc; 13. Piston; 14. Piston ring; 15. Bypass valve plate; 16 Bypass valve spring; 17. Plunger; 18. Plunger spring; 19. Rod guide bushing with fluoroplastic layer; 20. Rod guide bushing sleeve; 21. Rack housing sealing ring; 22. Rod seal; 23. Oil seal cage; 24. Rod protective ring gasket; 25. Protective ring of the rod; 26. Rack housing nut; 27. Compression buffer support; 28. Rod; 29 Suspension spring cup; 30. Rod limiting sleeve; 31. Rack housing; 32. Cylinder; 33. Piston assembly with recoil valve and bypass valve; 34. Compression valve assembly; 35 Pivot lever; I. Scheme of operation of the hydraulic stand; II Compression stroke; III. Recoil stroke.
The telescopic hydraulic strut is the main unit of the front suspension. It combines a group of parts, some of which perform the functions of a suspension guide device, and others - a damping element. The first group of parts includes the strut body and the parts of its fastening to the body and steering knuckle, the second - a hydraulic shock absorber mounted in the strut. The strut body 31 is made of a pipe, to the lower part of which the bottom is welded, and in the upper part an internal thread is cut for nut 26. On the outside, a bracket for connection with the steering knuckle, in the middle part a support cup 29 of the suspension spring and a steering arm 35 connected to the steering linkage are welded to the strut body. In the cheeks of the bracket there are two holes. Of these, the upper oval ones are for the adjusting bolt. A cylinder 32 is installed in the strut body, into the lower part of which a compression valve 34 is pressed. Its body is pressed to the bottom of the strut body. The compression valve consists of a housing 1, three flat disks 2 and 3, a plate 4, a spring 5 and a collar 6. In the center of the housing there is a chamfered seat to which the valve disks and plate 4 are pressed by spring 5. The other end of the spring rests against collar 6 pressed onto the seat belt of the valve housing. For the passage of fluid from the strut housing to the cylinder and back, a cylindrical groove and four vertical grooves are made in the lower part of the housing. The same grooves are also in the upper part of the compression valve housing. Disks 2 of the compression valve are flat, with openings in the center for the passage of fluid. In the central opening of disk 3 there are three cutouts for throttling the fluid at a low speed of movement of the rod. This disk is called a throttle disk. In the lower central part of plate 4 there is a cylindrical protrusion that covers the central opening of disks 2 and 3, but does not close the throttling cutouts. In the assembled valve, a gap is formed between the plate 4 and the disk 3 for the passage of liquid. For this purpose, eight through holes are made in the plate. The collar has a flange and a cylindrical belt on which the cylinder is mounted. This ensures tightness between the compression valve and the cylinder 32. On the stamped surface of the collar, six side holes and one central hole are made for the passage of liquid.
The cylinder contains a rod 28 assembled with a piston 33, on which a bypass valve and a recoil valve are mounted. The piston has twelve vertical valves located along two radii. Four channels located along the large radius are closed by a plate 15 of the bypass valve, pressed to the channels by a spring 16. The remaining valves are blocked from below by a pack of two discs of the recoil valve. The upper disc 12 is a throttle, has three cutouts along the outer diameter. The next disc 11 is flat. Both discs are pressed to the piston 13 by a spring 8 through a support plate 9. The piston assembled with the valves is fastened to the rod by a nut 7, which is locked by punching the rod in two places. To protect the discs of the return valve from damage during installation and to stabilize the operation of the valve, a washer 10 is installed between the discs and the nut. The piston is sealed in the cylinder with a ring made of filled fluoroplastic, due to which the wear resistance of the pair is sharply increased; cylinder - piston. A limiting sleeve 30 is pressed onto the rod and then welded, which, resting against the plunger 17 of the hydraulic recoil buffer, limits the recoil stroke.
The hydraulic recoil buffer consists of a plunger 17 and a spring 18, under the action of which the plunger is lowered down until it stops against the cylinder projection. Between the rod and the plunger there is a gap through which the cavities above and below the plunger communicate. Between the upper part of the plunger and the cylinder there is a calibrated gap for throttling the liquid, when the bushing 30 covers the gap between the rod and the plunger from the end. Between the rest of the plunger and the cylinder there is a significant gap due to the increase in the diameter of the cylinder in the area of the lower and middle part of the plunger (with the plunger in the lower position).
The movement of the rod in the cylinder is guided by a split bushing 19 with a fluoroplastic insert. Bushing 19 is pressed into guide collar 20. A drain pipe is installed in the channel of the collar, connecting the upper cavity of the collar with the annular groove of the telescopic strut body. The liquid that has passed through the gap between the rod and the guide sleeve is drained through this pipe, so that there is no foaming of the liquid due to contact with air. The collar assembled with the guide sleeve is pressed with a cylindrical belt onto the cylinder. The collar in the strut body is sealed with a rubber ring 21. Following the collar of the guide sleeve, a self-tightening seal 22 of a frame type with a collar 23, a gasket 24 and a protective ring 25 of the rod are installed in the strut body. All parts installed in the rack housing are pressed with nut 26. In this case, the sealing parts select the gaps between the parts, ensuring the tightness of the rack. The gland 22 is reinforced with a metal frame, due to which the required rigidity is achieved. Inside the gland there are two working edges adjacent to the surface of the rod. The pressing of one of the edges is provided by a spring, the other - due to the elasticity of the rubber of the gland. Therefore, the gland is called self-tightening. It is installed in a metal cage 23. A metal-ceramic ring protects the working surface of the rod from contamination. Support 27 is pressed onto the rack housing, against which the compression stroke buffer rests during the compression stroke. In the upper part of the rod there is a thread for the nut for fastening the upper support of the rack and chamfers for a key are made to hold the rod from turning when the nut is rotated.
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