The use of an automatic adjustment arm helps to balance the braking force distribution of each brake. The common problem encountered during the use of the automatic gap adjustment arm is the overheating of the brake, especially the front axle. What is the cause of this problem? The reasons are as follows.
1. The adjusting arm is not matched properly, and the setting gap is too small. Inspection method: The free stroke of the air chamber should be set to a gap between 1823mm. Otherwise, it should be re-matched. If there is no special requirement, it is recommended to set the gap between 0.81.0mm.
2. The friction plate material is unstable, and the expansion gap becomes smaller after being heated or absorbing water. Inspection method: The gap becomes smaller at the beginning of use, sometimes there is dragging phenomenon, this problem disappears after a period of use; Measures: Choose a stable friction plate as much as possible, and make several adjustments similar to the initial setting during the initial use stage.
3. The axial clearance of axle hub bearing is too large, which causes uneven distribution of the clearance between the brake drum and the brake, which is especially serious when the force is applied. It is recommended that the pre-tightening of the hub bearing be adjusted to the hub turning torque between 512Nm.
4. The rigidity of the brake is small, such as stamping and welding brakes or non-equal thickness friction plate brakes, and the adjusted gap is smaller than the theoretical calculation.
5. The rigidity of the brake drum is small, the heat capacity is small, the adjustment arm is automatically adjusted. When it returns to the non-braking state, the gap is smaller than the set value. After the heat expansion, the adjustment arm is automatically adjusted. After cooling, the brake drum The greater the stiffness, the better, especially it is necessary to enhance the stiffness of the opening, and the thickness of the opening should be 25mm
6. The brake chamber or brake return spring has insufficient elasticity or failure, causing the brake not to return and causing drag. The left and right brakes are different. There is a high point between the brake shoe and the brake drum. After the high point is worn away, this phenomenon can disappear. Another possibility is that the brake arms with the same shape and different internal preset gaps are mixed and installed incorrectly. Increase the heat dissipation of the brake, and use auxiliary braking when going down a long slope. At the same time, there will be insufficient braking force, that is, the phenomenon of soft braking, the main reasons are as follows. If there is a problem with the installation, ensure that the air chamber push rod and the adjustment are at an obtuse angle, and when the brake is in place, it is at a right angle to maximize the braking force. The stroke of the air chamber is not enough, and the stroke of the air chamber push rod exceeds the working range when forced to move, and the air chamber thrust drops rapidly, resulting in insufficient braking force. The initial gap is too large, sometimes in order to obtain a large gap, the preset gap is deliberately increased, causing the working area of the matched air chamber to fall in the area of rapid braking force, and the overheating of the brake leads to obvious thermal decay.
The automatic gap adjustment arm can only be adjusted in one direction, that is, the gap is adjusted from large to small, until the gap is automatically set, but cannot be adjusted from small to large. It should be emphasized that wheel drum brakes are not suitable for continuous braking. When the continuous braking work time is long and the braking is more frequent (such as urban buses), the brake will be overloaded with thermal load, causing thermal degradation, and even causing the brake to fail completely; therefore, it is recommended to use it for harsher operating conditions Disc brakes with better performance and heat dissipation conditions replace drum brakes, retarder brakes, engine exhaust brakes, etc. to increase the safety and reliability of the vehicle.
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