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Cause analysis of brake drum failure
发布时间:2022.08.24 新闻来源:澳门新莆京app7748-制动鼓,刹车鼓生产厂家

Cracking analysis

The brake drum is mainly subjected to two directions of force when working, one is the normal pressure from the shoe, the other is the tangential force generated by the rotation and the shoe clutch piece. The friction of brake drum and brake disc produces a lot of heat, leading to the temperature of the brake drum, and the friction of brake disc and brake drum is actually speckled contact, contact surface due to the heat generated by friction makes the tissue phase change, reducing the thermal fatigue resistance of the place; Due to the uneven heating, make the mechanical properties of the non-uniform, under the frequent braking load, has certain regularity of crack, crack is intermittent or continuous shape, the tangential force reduces the thermal fatigue strength, crack with the continuous extension of crack, crack mutual cross-linked reticular formation, usually speak both crack, serious crack cause craze. The picture

On the other hand, the brake drum working temperature can be up to 850℃~900℃, near 800℃ or slightly below 800℃, eutectic carbide decomposition into graphite and ferrite; Pearlite and ferrite are transformed into austenite above 800℃. Austenite is transformed into martensite upon rapid cooling.


Brake drum cracking

The cracking problem of the brake drum should be analyzed from two aspects. One is that under the braking condition, the material itself is broken due to the strength difference; Second, after cracking, the brake drum under the interaction of thermal stress and phase stress, due to the local strength reduction caused by the phase transformation of the tissue, under the frequent action of external braking force, the crack continues to extend, and finally cause the brake drum rupture. The failure of the brake drum crack is mostly generated at the working face of the brake belt. With frequent braking work, the crack gradually extends from the local stress point, and finally passes through the reinforcing belt to cause the brake drum to crack completely. The picture


Off the bottom

There are two aspects of the bottom, one is the brake drum material strength difference; The second is caused by unreasonable abnormal external force brake drum cracking.


Failure of excessive wear and tear

Excessive wear failure is mainly refers to the work of the brake drum with frequent under the action of braking force, work cause the brake drum with inner diameter geometry size, wall thickness thin, influence braking effect, even the brake failure, along with the constant development of new wear-resisting material, the hardness of friction plate is becoming more and more high, the requirement to the brake drum (especially the hardness requirement) also more and more high accordingly.


Abnormal wear failure

About the failure of abnormal wear, mainly refers to the brake drum working face under the action of hard shoe, grinding out grooves, this phenomenon is caused by the shoe friction piece riveting unreasonable, and the hardness of the brake drum also has a certain relationship.

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