How does a clutch release bearing work?

Clutch release bearing is a very important part in automobile manual gearbox, its main role is to achieve the separation of the clutch plate, so as to cut off or connect the power transmission between the engine and the gearbox. The following is the working principle and relevant details of the clutch release bearing:

 I. Basic structure of automobile manual gearbox

1. Release bearing: usually a bearing with ball or roller, mounted in the centre of the clutch pressure plate. The release bearing can rotate and move in the axial direction.

2. Release fork: attached to the clutch pedal and operated hydraulically or mechanically. The release fork is responsible for pushing the release bearing.

3. clutch pressure plate: presses against the flywheel and clutch disc and transmits the engine power.

4. Return spring: ensures that the release bearing remains in its initial position when not in use.

 Second, the working principle of the clutch release bearing

1. Engaged state:

   - When the clutch pedal is not pressed down, the release bearing is kept in the non-operating position under the action of the return spring, keeping a distance of about 3-4mm from the release lever. At this time, the clutch pressure plate will be released by the spring.

   - At this time, the clutch pressure plate presses the clutch disc through the spring force, so that the clutch disc and the flywheel are in close contact and the engine power is transmitted.

2. Separation process:

   - When the driver depresses the clutch pedal, the clutch pedal pushes the release fork through a hydraulic or cable pull system.

   - The movement of the release fork causes the release bearing to move forward and press against the release finger (also known as the release jaw) of the clutch pressure plate.

   - The release bearing pushes on the release finger, causing the clutch pressure plate to recede relative to the flywheel, thereby reducing pressure on the clutch disc.

   - As the pressure on the pressure plate decreases, the friction between the clutch disc and the flywheel decreases, the clutch is in a disengaged state, and power transmission is cut off.

3. Sealing process:

   - When the driver slowly releases the clutch pedal, the thrust on the release bearing decreases and the release finger gradually returns.

   - With the return of the release finger, the clutch pressure plate presses the clutch disc again, the friction between the clutch disc and the flywheel increases, and the power transmission is re-established.

 Third, the clutch release bearing performance requirements

1. Flexibility of movement: the movement of the release bearing should be flexible, without sharp noise or stagnation phenomenon.

2. Axial clearance: the axial clearance shall not exceed the specified value (generally within 0.60mm).

3. Wear of the inner seat ring: the wear of the inner seat ring shall not exceed the specified value (generally within 0.30mm).

4. automatic centring design: in modern design, the release bearing may adopt automatic centring structure, such as angular contact ball bearing, this design allows the bearing to be fixed in the outer ring, the inner ring rotating automatic centring, reduce wear and noise, improve service life.

 Fourth, clutch release bearing failure analysis

1. High working temperature: long time high temperature operation may lead to bearing material aging.

2. Lack of lubricating oil: Insufficient lubrication will increase friction and lead to premature wear of bearing.

3. too little free travel: too little free travel of the clutch pedal will lead to excessive force on the release bearing.

4. Excessive loads: Frequent clutch operation will accelerate bearing wear.

5. Failure of the return spring: failure of the return spring will result in the release bearing not being able to return, affecting the normal operation of the clutch.

 V. Lubrication and cooling

1. Lubrication: The harsh working conditions of the release bearing require good lubrication. Some designs improve the lubrication conditions by sealing structure and using high temperature grease to reduce the heat and wear caused by high speed friction.

2. Cooling: Release bearings operate under uncooled and poor lubrication conditions and are subject to axial and radial forces as well as centrifugal forces generated by high-speed rotation, so their durability and lubrication are critical.

 Sixth, maintenance and inspection of clutch release bearing

1. Regular inspection: Check the wear of the release bearing periodically to ensure that its axial clearance and inner seat ring wear are within the specified range.

2. Lubrication: Add or replace the lubricant regularly to ensure the release bearing is well lubricated.

3. Adjustment of freewheeling travel: check and adjust the freewheeling travel of the clutch pedal to ensure that it is within the limits specified by the manufacturer.

4. professional maintenance: if unsure how to perform maintenance or inspection, consult a professional automotive service technician.

 Summarising

The clutch release bearing achieves rapid clutch disengagement through precise mechanical linkage to ensure smooth vehicle shifting. Its design and maintenance are crucial to the performance and life of the whole transmission system. With the above detailed analysis, we hope you can better understand and maintain this key component.