What does "car separation bearing" mean?
The automotive clutch release bearing, also known as the clutch release bearing or the commonly referred to "clutch spring plate", is a crucial component in the manual transmission clutch system of a car.
Its core function is to transfer the axial thrust when the driver depresses the clutch pedal, pushing the rotating release lever (or lever) away from the rotating pressure plate, thereby overcoming the pressure of the pressure plate spring and causing the pressure plate to separate from the clutch disc, cutting off the power transmission from the engine to the gearbox, and enabling smooth gear shifting.
Working principle and function
Standby state: When the clutch is in the engaged state (no pedal depressed), the release bearing usually does not come into contact with the rotating pressure plate lever, or only maintains a very small gap.
Action execution: When the pedal is depressed, through hydraulic or mechanical mechanisms, the release bearing is pushed axially (towards the engine) to move.
Force transmission and separation: The front end of the release bearing presses against the rotating pressure plate lever. The rolling elements (balls or rollers) in its interior enable the inner ring to rotate synchronously with the lever, while simultaneously transferring the non-rotating axial thrust from the pedal smoothly to the rotating part, forcing the pressure plate to move backward and releasing the clamping force on the clutch disc.
Key technical parameters and maintenance
Axial clearance: It should be controlled within ≤0.60mm. Excessive clearance will lead to incomplete separation, while too little will accelerate wear.
Inner race wear: The wear should not exceed 0.30mm.
Lubrication: Regular use of lithium-based lubricating grease is required to reduce wear and overheating. Poor lubrication is one of the main reasons for early damage to the release bearing.
Installation gap: Through the return spring, the raised shoulder of the release bearing and the release fork should maintain a gap of approximately 3-4mm to ensure it is in the correct working position.
Common faults and causes
The working environment of the release bearing is harsh, bearing axial loads, impact loads, high-speed rotating radial centrifugal force, and high temperatures, with poor lubrication conditions. Common faults include abnormal sounds or sticking, mainly caused by:
Lubrication failure: Lack of lubricating oil or loss of lubricating grease, aging, leading to dry friction between the rolling elements and the raceway.
Overheating and ablation: Drivers habitually "half-press" the clutch (in a semi-engaged and semi-separated state) or keep their foot on the clutch pedal for a long time, causing the bearing to rotate at high speed for a long time and generating a large amount of heat, resulting in melting of the lubricating grease and bearing ablation.
Pollution and seal failure: Aging and damaged sealing rings allow dust, impurities to enter or lubricating grease to leak.
Improper operation and wear: Frequent depressing of the clutch, improper adjustment of the free travel, unevenness of the release lever, etc., will accelerate its wear.
Abnormal sound diagnosis
If a clear "squeaking", "clicking" or "clattering" sound is heard when depressing or lifting the clutch pedal, and the sound disappears or changes when releasing the pedal, this is typically a typical sign of a damaged release bearing.
Reasons for damage to the automotive clutch release bearing (usually referring to the clutch release bearing) are diverse, mainly classified into several categories: lubrication, driving habits, improper adjustment, component condition, and external factors.
Main causes of damage
Poor lubrication: This is one of the most common reasons. The lubricating grease (grease) inside the release bearing will deteriorate, melt, or deteriorate over time due to heat or age. If there is a lack of lubrication for a long time, the bearing will generate a large amount of heat due to dry friction, leading to increased wear, a sharp increase in temperature, and eventual burnout or sticking.
Bad driving habits:
Frequent semi-engaged operation: During driving, such as in traffic jams, turns, or when slowing down, if the clutch pedal is kept in a semi-engaged and semi-separated state for a long time, the clutch will be in a semi-engaged and semi-separated state. This will cause the separation bearing and the separation lever to continuously rub against each other, generating a large amount of heat, causing the bearing temperature to rise excessively, and leading to the failure of the lubricating grease, thereby accelerating the damage.
Foot-operated clutch pedal: If the foot remains on the clutch pedal after shifting gears, the separation bearing will remain in a working state, increasing unnecessary wear and the number of load-bearing times.
Incorrect free travel adjustment:
Too small or zero free travel of the clutch pedal: If the free travel of the clutch pedal is adjusted too small or not at all, the separation lever will continuously press against the separation bearing, causing the bearing to remain under load for a long time and unable to return normally. This will result in overheating of the bearing, fatigue damage, and a sharp reduction in lifespan.
Excessive free travel: Although not as serious as the former, it will also cause the clutch to not separate completely, increasing the impact of gear shifting and the intermittent load on the bearing.
Problems with the separation lever and return spring:
Uneven surface of the separation lever: If the end face of the separation lever is uneven or has inconsistent heights, it will cause the separation bearing to be subjected to uneven force during operation, resulting in additional torque and wear.
Poor return spring: The insufficient or failed return spring will cause the separation bearing to fail to return completely and timely after releasing the pedal, resulting in its continuous contact with the separation lever and increased wear.
Installation and quality issues:
Installation errors: During the repair process, if the bearing installation position is incorrect, the coaxiality deviation is too large, or if the operation is not carried out according to the specifications, the bearing will be subjected to abnormal force during operation and be damaged.
Poor quality of the bearing: Using inferior or counterfeit separation bearings with unqualified materials, heat treatment processes, or manufacturing accuracies will result in poor wear resistance and fatigue resistance, and they are prone to early damage even under normal use.
Working environment and load: The separation bearing works in a harsh environment of high temperature, high rotational speed, and intermittent impact loads, without a dedicated cooling system. Long-term overloading driving or frequent sudden acceleration and deceleration will also increase its load, accelerating fatigue damage.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
