Medium and heavy trucks basically use compressed air as the braking medium, and the air compressor pumps the air and stores it in the air tank.With each brake ,the compressed air releaes the force one the sub-cylinder and pushes the brake shoes to brake. In addition to tire friction and sufficient air pressure, whether the braking effect is good or not depends on the output of the brake cylinder.

The most common type on trucks it the dual-chamer brake chamber ,and its standard name is the energy-storage spring brake chamber. This air chamber combines the two functions of service brake and parking brake, and is widely used on drive shafts and trailer shafts.

It can be seen from the planing plan of the dual-chamber brake air chamber above that the dual-chamber brake air chamber has two air ports, which are connected to the driving chamber and the parking chamber respectively.

The clutch master cylinder and the sub-cylinder are equivalent to two hydraulic cylinders. There are oil inlet and outlet pipes on the master pump, and only one pipe for the sub-cylinder. When the clutch is stepped on, the pressure of the master cylinder is transmitted to the sub-cylinder, the sub-cylinder works, and the disengagement fork removes the clutch pressure plate and disc from the flywheel, and then the gear shift can be started. When the clutch is released, the sub-cylinder stops working, the clutch pressure plate and disc contact the flywheel, the power transmission continues, and the oil of the sub-cylinder flows back into the oil pot. When it is difficult to change gears and the separation is not complete, it is necessary to check whether the clutch master cylinder and the sub-cylinder have oil leakage, and solve the problems in time to reduce wear.

Clutch sub-cylinder failure and explanation

一：The clutch is not completely separated, it is difficult to change gears, and it fails again after a period of time after debugging.

There are three reasons:

1. The clutch pedal and the eccentric pin nut connecting the master cylinder are loose; 2. The main pump push rod nut is loose; 3. There is a problem with the pressure plate and driven plate of the clutch driven plate assembly;

Solution: 1. Tighten the eccentric pin nut; 2. Adjust the clearance of the push rod nut and then tighten the pin; 3. Replace with a new pressure plate or driven piece

(2) The clutch is heavy, cannot be separated, and gear shifting is difficult Reasons: 1. The air inside the sub-pump is exhausted; 2. The push rod clearance of the master cylinder is too large, which makes the effective stroke of the sub-cylinder insufficient; 3. The large elastic deformation of the sub-cylinder bracket reduces the effective stroke; 4. The welding angle of the clutch release rocker arm is out of tolerance, resulting in too much out of tolerance in the center distance between the flange end of the connecting sub-cylinder and the fork hole of the release arm. In addition, the push rod of the sub-cylinder cannot be adjusted, causing insufficient stroke; 5. Excessive clearance of the gear shift linkage mechanism causes resistance; 6. The release bearing is not lubricated, and the inner hole is rough; 7. The master cylinder and the sub-cylinder do not match

Solution: 1. Drain the undischarged air; 2. Adjust the pump push rod to the best effective stroke; 3. Re-reinforce the sub-pump bracket; 4. Re-welding to reduce the angle error between the separation arm and the center distance; 5. Replace the gear shift linkage mechanism; 6. Replace the related parts that have been napped, and add lubricating oil; 7. Replace the master pump that matches the sub-cylinder;

(3) The clutch pedal is stepped on and heavier, and the clutch pedal is stepped on higher and higher, slipping; Reason: The push rod of the master cylinder was adjusted down too far, so that the one-way valve of the piston was closed. The pressure oil of the sub-cylinder cannot come back, and the clutch disc will be burnt out in severe cases. To Solution: readjust the push rod gap. (4) The clutch pedal is hard pressed to the lower part, and is not in place, and cannot be separated Reason: The push rod of the sub-cylinder is adjusted too far. To Solution: re-adjust the separation push rod gap.

2 The clutch sub-cyliner leaks

the reason: 1. The air path is not clean, and the sealing surface of the air valve in the pump is jammed by foreign objects and cannot be sealed; 2. The working environment is bad and the dust is too large, causing the apron in the cylinder to wear out in advance; 3. The return of the master cylinder is not complete, and the one-way valve in the sub-cylinder is not sealed. To Solution: 1. Clean up foreign objects in the cylinder, add lubricating oil, and replace damaged seals; 2. Check and replace the master cylinder. 3 Clutch sub-cylinder exhaust air.

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