What is a clutch release bearing

The clutch release bearing, also known as the clutch throwout bearing, is a key component in the clutch system. It is located between the clutch and the transmission, and its main function is to eliminate the heat and resistance generated by the direct friction between the clutch pressure plate and the flywheel, ensuring that the clutch can be smoothly engaged and disengaged. When the driver depresses the clutch pedal, the clutch release bearing is pressurized and pushes the clutch pressure plate backward to separate the clutch plate from the flywheel; when the driver releases the clutch pedal, the clutch release bearing releases the pressure, and the clutch pressure plate moves forward under the action of the spring to tightly combine the clutch plate with the flywheel. Therefore, the performance of the clutch release bearing directly affects the operation smoothness and service life of the clutch.

The main reasons for clutch release bearing failure are as follows:

The clutch release bearing is an important part of the automobile transmission system, and its main function is to push the diaphragm spring on the clutch pressure plate when the driver depresses the clutch pedal, so that the clutch plate separates from the flywheel, thus disconnecting the connection between the engine and the transmission. When the driver releases the clutch pedal, the diaphragm spring presses on the clutch plate, reconnecting the engine and transmission so that engine power can be transferred to the wheels.

1. High working temperature: many drivers in the turn or deceleration, often half-pedal clutch, some gear foot is still placed on the clutch pedal; some vehicles free travel adjustment is too large, so that the clutch separation is not complete, in the half-engagement and half-disengagement state, this state causes dry friction and generate a lot of heat transfer to the separation bearing, bearing heat to reach a certain temperature, the grease melt or dilution of flow, so that the separation of The bearing is heated to a certain temperature, the grease is melted or diluted and flows, so that the temperature of the separation bearing is further increased, and when the temperature reaches a certain level, it will be burnt.

2. Lack of lubricating oil: In practice, drivers tend to ignore this point, resulting in clutch release bearing oil shortage. In the case of no lubrication or less lubrication, the amount of wear on the release bearing is often several to several dozen times the amount of wear after lubrication. With increased wear, the temperature will also increase considerably, which makes it more susceptible to damage.

3. Free travel is too small or loaded too many times: according to the requirements of the general clutch release bearing and the clearance between the release lever for 2.5mm is more appropriate, reflected in the clutch pedal on the free travel of 30-40mm, free travel is too small or there is no free travel, will make the release lever and the release bearing in the state of constant engagement. According to the principle of fatigue damage, the longer the working time of the bearing, the more serious the damage; the more the number of loaded, the more likely to produce fatigue damage of the release bearing. And the longer the working time, the higher the temperature of the bearing, the easier it is to burn, reducing the service life of the separation bearing.

4. Whether the separation lever is adjusted flat or not: whether the separation lever is adjusted flat or not, whether the separation bearing return spring is good or not, also has a great influence on the damage of the separation bearing. If the separation lever is not adjusted flat and the spring force of the return spring of the separation bearing is insufficient, it will cause the separation bearing to be subjected to uneven load during operation, which will aggravate the wear and damage.

5. Wear and tear: The surface of the bearing will gradually wear out due to the presence of relative motion during operation. If the degree of wear is serious, it will lead to loss of dimensional accuracy of the bearing, which in turn will affect its normal operation. Wear may be caused by poor lubrication, ingress of impurities or poor quality of bearing materials.

6. Some drivers are accustomed to using a half-leg clutch: the clutch is in the state of half-engagement, half-disengagement, causing dry friction of the clutch, heat transfer to the release bearing, resulting in the loss of grease inside the bearing becomes thin, when the temperature reaches a certain value of the bearing erosion damage.

7. When carrying out vehicle maintenance: omitting to install or losing the small oil bottom, resulting in mud and dirt intrusion into the release bearing, causing bearing wear.

8. Clutch pedal free travel is too small or not: so that it is in a state of frequent engagement, causing fatigue damage or even ablation; pedal travel is too large, resulting in incomplete separation of the clutch, gear difficulty, the clutch is in a state of half-engagement and half-disengagement, resulting in dry friction, the heat is transmitted to the release bearing, so that grease run out, bearing ablation.

9. External factors: External factors such as high temperature, corrosion, vibration, etc. may also cause damage to the clutch release bearing. For example, high temperature environment will accelerate the deterioration of grease and aging of bearing materials; corrosive media will erode the bearing surface; vibration may lead to bearing loosening or damage.

10. Separation bearing and separation sleeve with poor fit: in particular, the two fit clearance is too large, loose, and not in a plane, the work of the separation bearing is subjected to shock load, so that the track wear, ablation.

11. Overload or stress concentration:

When the clutch release bearing is subjected to excessive load or stress concentration, it may exceed the strength limit of its material, resulting in bearing damage. This may be due to improper driver operation, poor clutch system design or vehicle overloading.

12. Fatigue failure:

Clutch release bearings may experience fatigue failure due to repeated exposure to alternating stresses during long-term use. Fatigue failure is usually manifested as particle spalling or crack formation on the surface of the bearing, which ultimately results in the bearing failing to work properly.

13. Improper installation:

The installation quality of the clutch release bearing has an important impact on its performance. If there is a deviation in the installation process or not in accordance with the specifications for operation, it may lead to uneven bearing force on the shaft or fit clearance is too large/small, thus accelerating the wear and failure of the bearing.

These are the main causes of clutch release bearing failure. To avoid these problems, drivers should follow proper operating procedures, perform regular vehicle maintenance to ensure that the release bearing is adequately lubricated, and pay attention to adjusting and checking the free travel of the clutch pedal to extend the service life of the release bearing.