Application and maintenance of clutch release bearing

The clutch release bearing is a relatively important part of the car. If it is not properly maintained and causes failure, it will not only cause economic losses, but also be very troublesome to disassemble and assemble once, which requires a lot of man-hours. Therefore, it is of great significance to understand the reasons for the failure of the clutch release bearing and to perform reasonable maintenance and maintenance during use to extend the life of the release bearing, improve labor productivity, and achieve better economic benefits.

The clutch release bearing is installed between the clutch and the transmission. The release bearing seat is sleeved on the tubular extension of the first shaft bearing cover of the transmission. The return spring keeps the shoulder of the release bearing against the release fork and retreats to the final position. Keep a gap of approximately 2.5 mm from the release lever. Since the clutch pressure plate and release lever operate synchronously with the engine crankshaft, and the release fork can only move axially along the clutch output shaft, it is obviously not possible to directly use the release fork to move the release lever. The release bearing can make the release lever rotate while moving along the clutch. The output shaft moves axially, thereby ensuring smooth clutch engagement, gentle separation, reducing wear, and extending the service life of the clutch and the entire drive train. The clutch release bearing should move flexibly without sharp noise or sticking. Its axial clearance should not exceed 0.60 mm, and the wear of the inner race should not exceed 0.30 mm.

The damage of the clutch release bearing is closely related to the driver's operation, maintenance and adjustment. The causes of damage are generally as follows:

1) Overheating caused by excessive operating temperature. Many drivers often half-depress the clutch when turning or decelerating, and some put their foot on the clutch pedal after shifting into gear; some vehicles have excessive free travel adjustment, causing the clutch to be incompletely disengaged and in a half-engaged and half-disengaged state. The state causes sliding friction between the friction plate and the flywheel, which generates a large amount of heat and transfers it to the release bearing. When the bearing is heated to a certain temperature, the grease melts or dilutes and flows, further increasing the temperature of the release bearing. When the temperature reaches a certain level, it will burn. Bad release bearing.

2) Wear due to lack of grease. The clutch release bearing is lubricated with grease. In actual work, repairmen tend to ignore the lubrication problem of the release bearing and do not add grease to the release bearing during installation, causing the clutch release bearing to be short of oil. The amount of wear of unlubricated or poorly lubricated release bearings is often several to dozens of times that of lubricated release bearings. As wear increases, the temperature will also increase greatly, making it easier to damage the release bearing. Therefore, during the repair process, when installing the clutch, check the lubrication condition of the release bearing and add grease in time for maintenance.

3) The free stroke is too small or the load times are too many. According to the requirements, the clearance between the clutch release bearing and the release lever is generally 2.5mm, which is more suitable. The free travel reflected on the clutch pedal is 30~40 mm. If the free travel is too small or there is no free travel at all, it will cause the release lever to The release bearing is in a normally engaged state. According to the principle of fatigue damage, the longer the bearing works, the more serious the damage will be; the more times it is loaded, the easier it is for the release bearing to suffer from fatigue damage. Moreover, the longer the working time, the higher the temperature of the bearing, and the easier it is to burn out, reducing the service life of the release bearing.