What is the clutch bearing？

1. Working principle

When the clutch release bearing works, the force of the clutch pedal will be transmitted to the clutch release bearing. The clutch bearing moves to the center of the clutch pressure plate so that the pressure plate is pushed away from the clutch plate, separating the clutch plate from the flywheel. When the clutch pedal is released, the spring pressure in the pressure plate will push the pressure plate forward and press it against the clutch plate to separate the clutch plate from the clutch bearing and complete a working cycle.

2.Cause of failure

(1) Excessive operating temperature causes overheating. When turning or decelerating, many drivers often half step on the clutch, and some put their feet on the clutch pedal when they are in gear; In some vehicles, the free travel adjustment is too large, so that the clutch is not completely separated and is in the state of half engagement and half separation. This state causes sliding friction between the friction disc and the flywheel, resulting in a large amount of heat transmitted to the release bearing. When the heat of the shaft reaches a certain temperature, the lubricating grease melts or dilutes and flows, further increasing the temperature of the release bearing, When the temperature reaches a certain level, the release bearing will be burned out.

(2) Wear due to lack of grease. The clutch release bearing is lubricated with grease. In actual work, it is easy for the repairman to ignore the lubrication problem of the release bearing and do not add grease to the release bearing during installation, resulting in lack of oil in the clutch release bearing. The wear of non lubricated or less lubricated release bearings is often several to dozens of times that of lubricated release bearings. With the increase of wear, the temperature will also increase greatly, which is more likely to damage the release bearing. Therefore, during the repair process, when installing the clutch, check the lubrication of the release bearing and add lubricating grease in time for maintenance.

(3) The free travel is too small or loaded too many times. According to the requirements, the clearance between the clutch release bearing and the release lever is generally 2.5mm, and the free stroke reflected on the clutch pedal is 30 ~ 40mm. If the free stroke is too small or there is no free stroke at all, the release lever and the release bearing will be in a constant engagement state. According to the fatigue failure principle, the longer the working time of the bearing, the more serious the damage is; The more loading times, the easier the release bearing is to produce fatigue failure. Moreover, the longer the working time, the higher the temperature of the bearing, the easier it is to burn and reduce the service life of the release bearing.

(4) Whether the release lever is adjusted smoothly, whether the release fork is deformed, and whether the return spring of the release bearing is good also have a great impact on the damage of the release bearing. Uneven release adjustment, deformation of release fork and non return of release bearing spring will cause the release bearing to be butted during clutch operation, so that the release bearing is always in the working state. The temperature is higher and higher, which is easy to burn the release bearing and reduce the service life of the release bearing.