Clutch Release Bearing Introduction

A clutch release bearing, also known as a release bearing, is a key mechanical component in a manual transmission vehicle, located between the clutch and the transmission. Its main function is to push the clutch pressure plate backward through a series of mechanical linkages when the driver depresses the clutch pedal, thus separating the pressure plate from the driven disc, interrupting the power transmission from the engine to the transmission system, and allowing the vehicle to shift gears. This ensures smooth engagement and disengagement of the clutch and reduces wear, thus extending the service life of the entire transmission system.

Role of clutch release bearing

The main role of the clutch release bearing is:

Transmitting power: When the clutch is engaged, the release bearing ensures that the clutch pressure plate is in close contact with the flywheel, thus transmitting engine power to the transmission.

Separating the clutch: when the driver depresses the clutch pedal, the release bearing pushes the clutch pressure plate, separating the clutch disc from the flywheel, cutting off the transmission of power from the engine and allowing the driver to perform the gearshift operation.

Clutch Release Bearing Working Principle

The working principle of the clutch release bearing is based on mechanical principles and spring action. Specifically:

Spring action: the release bearing uses the action of the return spring to always maintain a clearance of approximately 3 to 4 mm with the release lever, ensuring that the clutch operates in synchronisation with the engine crankshaft.

Disengagement and engagement: When the driver depresses the clutch pedal, the pedal pushes the clutch release bearing forward through the linkage mechanism. The bearing compresses the diaphragm spring behind the clutch pressure plate, reducing the contact pressure between the pressure plate and the clutch disc, thus disengaging the clutch. When the driver releases the clutch pedal, the diaphragm spring returns to its original position and pushes the pressure plate into close contact with the clutch disc, thus transmitting engine power.

How long does a clutch release bearing last?

Clutch Release Bearing Life

The life of a clutch release bearing is not fixed, it is affected by a number of factors, including driving habits, maintenance conditions, vehicle use environment and so on. Theoretically, a good release bearing can last for the entire life of the vehicle under normal maintenance and reasonable use. However, with frequent semi-clutch operation (e.g. frequent starting and stopping in the city), or insufficient lubrication, the release bearing will fail prematurely due to overheating and wear, and the usual life span may vary from tens of thousands of kilometres to over one hundred thousand kilometres. Regular inspection, proper lubrication and avoiding long periods of semi-clutching can prolong its service life. If there is a noise or difficulty in shifting gears, it may be a sign that the release bearing is worn out and needs to be inspected and replaced in time.

In order to extend the service life of the clutch release bearing, vehicle owners should carry out regular vehicle maintenance, such as lubricating the bearing and adjusting the free travel of the release lever. At the same time, during driving, one should avoid half-pressing the clutch pedal for a long time to reduce the wear on the bearing.

What kind of structure does the clutch release bearing adopt to improve its service life?

The clutch release bearing adopts the structure of angular contact ball bearing and combines the full seal design with high temperature lithium grease, which significantly improves the service life. This design improves the shortcomings of traditional thrust ball bearings or deep groove ball bearings, which are mainly reflected in the following aspects:

1. Angular contact ball bearings: These bearings are able to withstand a combination of radial and axial loads and are better suited to the complex forces that clutches are subjected to during the disengagement process. Their design permits better load distribution and reduces localised overloads.

2. Fully sealed structure: The fully sealed design prevents dust and moisture from entering the inside of the bearing, keeping the grease clean and effective and avoiding early wear.

3. High-temperature lithium grease: the use of high-temperature resistant grease ensures that the bearing can still be well lubricated under the high temperature environment when the clutch is working, and reduces lubrication failure caused by high temperature.

4. Automatic alignment: The design enables the bearing to automatically adjust to align with the centre of the release lever, which reduces wear and prolongs service life even in the case of slight deflection.

5. Application of wave springs: Wave springs fitted between the outer ring and the separating sleeve ensure that the bearings fit snugly in non-operating conditions, reducing unwanted wobbling and wear, while providing smooth radial movement when required.

6. Inner ring rotation design: Changing the traditional design to allow the inner ring to rotate while the outer ring is fixed not only improves lubrication conditions, but also promotes grease circulation through centrifugal force, further enhancing bearing durability.

Through these comprehensive design improvements, the life of the clutch release bearing has been significantly enhanced, reducing maintenance requirements and improving vehicle reliability and driving experience.

In summary, the clutch release bearing is an indispensable key component in the automotive transmission system, and its role is to ensure the smooth engagement and disengagement of the clutch, thereby transmitting or cutting off engine power. Theoretically, a good release bearing can accompany the entire service life of the vehicle under normal maintenance and reasonable use. However, with frequent half-clutch operation or inadequate lubrication, the release bearing will fail prematurely due to overheating and wear, and the usual life span may vary from tens of thousands of kilometres to more than 100,000 kilometres. Regular inspection, proper lubrication, and avoidance of prolonged semi-clutching can extend its life.