6.5. Shock-absorbers

Shock-absorbers of forward and back suspension brackets differ in the sizes, in the way of fastening of the top part. Besides, the forward shock-absorber has other parametres of performance data. Internal constructive elements and a principle of work of shock-absorbers are almost identical.

Fig. 6.3. Shock-absorbers of forward and back suspension brackets: 1 – the bottom eye; 2 – the case of the valve of compression; 3 – disks of the valve of compression; 4 – a throttle disk of the valve of compression; 5 – a spring of the valve of compression; 6 – a holder of the valve of compression; 7 – a plate of the valve of compression; 8 – a nut of the valve of return; 9 – a spring of the valve of return; 10 – the shock-absorber piston; 11 – a plate of the valve of return; 12 – disks of the valve of return; 13 – a piston ring; 14 – a washer of a nut of the valve of return; 15 – a throttle disk of the valve of return; 16 – a plate перепускного the valve; 17 – a spring перепускного the valve; 18 – a restrictive plate; 19 – the tank; 20 – a rod; 21 – the cylinder; 22 – a casing; 23 – the directing plug of a rod; 24 – a sealing ring of the tank; 25 – a holder of an epiploon of a rod; 26 – a rod epiploon; 27 – a lining of a protective ring of a rod; 28 – a protective ring of a rod; 29 – a tank nut; 30 – the top eye of the shock-absorber; 31 – a nut of fastening of the top end of the shock-absorber of a lobby under вески; 32 – a spring washer; 33 – a washer of a pillow of fastening of the shock-absorber; 34 – pillows; 35 – распорная the plug; 36 – a casing of the shock-absorber of a forward suspension bracket; 37 – the rod buffer; 38 – резинометаллический the hinge

The back shock-absorber consists of the tank 19 (fig. 6.3) with an eye, the compression valve (poses. 2, 3, 4, 5, 6, 7), the working cylinder 21, a rod 20 with the piston 10 and valves of return and перепускным and a casing 22 with an eye. The tank 19 is made of a steel pipe on which bottom end the eye 1 is welded, and in the top part the carving for a nut 29 is cut. The case is inserted Into eye bore 2 valves of compression in gathering with valve disks. It is drawn in to bore by the working cylinder 21. The ring space between the tank and the cylinder is filled by a liquid. In the working cylinder the rod 20 with the piston 10 is located.

The piston has the vertical channels located on two circles. Channels on a small circle are closed from below by disks 12 and 15 valves of return, and on big – from above a plate 16 перепускного the valve.

The compression valve is located in the bottom part of the cylinder. In the case 2 valves are executed a nest to which 7 disks 3 and 4 are drawn in by a spring 5 through a plate. The disk 4 throttle, has cut, through which дросселируется a liquid at small speed of moving of the piston. In the bottom part of the case of the valve it is executed cylindrical проточка and four vertical channels, and in a holder 6 – six lateral and one central apertures through which the liquid passes from the tank in the cylinder and back.

From above in the cylinder the directing plug 23 which is condensed in the tank by a ring 24, and a rod exit – an epiploon 26 with a holder 25 is established. All details located in the top part of the cylinder, are drawn in by a nut 29. In eyes of shock-absorbers запрессованы резинометаллические hinges 38.

GOOD ADVICE For repair of shock-absorbers the special equipment is required, besides, this work means presence at the executor of experience of similar work. Shock-absorber repair in garage conditions usually does not lead to desirable result. Therefore repair shock-absorbers in a specialised workshop.

Condition of shock-absorbers check:

– External examination. At detection потеков absorber liquids remove shock-absorbers for repair in specialised workshops;

– Subjectively – by efficiency of clearing of fluctuations of the car at movement. At decrease in efficiency of clearing of fluctuations or occurrence of frequent rigid blows at a release and compression ("breakdowns") of suspension brackets remove shock-absorbers for check and repair in specialised workshops;

– The most correct is check of shock-absorbers at special stands (as the shock-absorbers established on the car, and dismantled).

GOOD ADVICE Faulty shock-absorbers change only in steams (lobbies, back) or the complete set (all four).

1. Establish the car on an equal platform (or an equal floor in garage). Switch off the engine, include in a transmission I transfer or backing transfer. A lay brake do not use.

2. Shake the car for a corner (wing) upwards-downwards with amplitude not less than 50 mm.

3. In the bottom point release hands.

4. If the car has made one fluctuation upwards, then half of course downwards and has stopped, the shock-absorber is serviceable.

5. Repeat operations 2–4 for other three shock-absorbers.

For definition of working capacity of the shock-absorber remove it from the car (subsections «Forward suspension bracket» and «the Back suspension bracket» see) and check up on динамометрическом the stand its working diagramme.

Working diagrammes remove according to the instruction applied on the stand, after performance not less than 5 running cycles at temperature of a working liquid of the shock-absorber 20±5 °С, frequency of rotation of a flywheel of the stand of 60 mines^-1 and length of a course of a rod of 100 mm for the forward shock-absorber.

Fig. 6.4. The working diagramme of the shock-absorber: 1 – effort at a return course; 2 – effort at a compression course

The diagramme curve (fig. 6.4) should be smooth, and in transition points (from a return course to a compression course) without the sites parallel to a zero line.

Estimation of results under the diagramme. The point of resistance of a course of return at scale 47 Н (4,8 кгс) on 1 mm should be from a zero line on distance And, equal: 33,3–40,7 mm for forward shock-absorbers, 23,5–30,5 mm for back shock-absorbers.

The highest point of a curve of a course of compression at the same scale should be from a zero line on distance In, equal 3,5–6,5 mm for forward and back shock-absorbers.

Control values of ordinates on diagrammes of forward and back shock-absorbers are set for cold shock-absorbers at temperature absorber liquids 20±5 °С.

After check remove the shock-absorber from the stand and if necessary touch and replace the damaged details.

Repeat test to make sure of serviceability of the shock-absorber.