Analysis and diagnosis of abnormal noise of tractor chassis clutch

The abnormal noise of the clutch is mainly manifested in the process of separation or engagement, as well as when the speed changes. When the clutch pedal is pressed or released, an abnormal sound can be heard at the clutch.

(1) Failure cause analysis.

① The release lever often contacts with the release bearing and makes a noise. This is because the clearance between the release lever and the release bearing is too small, the adjustment is unbalanced, or the pedal return spring is too soft, falling off or broken, or the bearing seat return spring is soft, broken, extended, falling off, etc., which causes the release lever and the release bearing to contact frequently and produce abnormal noise.

② The release bearing is short of oil or damaged. This situation will cause noise when the release bearing rotates, which is not flexible or even can not rotate. In the process of clutch separation, when the end face of release bearing and the end of release lever just contact, dry friction occurs and makes a noise.

③ The release lever breaks and makes a noise. When the release lever is broken, the pressure plate will skew when the clutch is released, resulting in incomplete separation of the driving and driven plates.

④ The rivet of clutch driven plate friction plate is loose, the riveting between driven plate and driven plate hub is loose or the pin hole of release lever and pin shaft are worn and loose. This kind of fault is to engage the clutch when starting, and to release the clutch when driving, the loose riveting parts or fitting parts will impact and make abnormal noise.

⑤ The key slot of the driven disk hub and the spline teeth of the clutch shaft are severely worn and the fit is loose. When the clutch is engaged or disengaged, the loose mating parts will impact, that is to say, the collision sound will be produced.

(2) Check the diagnosis method.

① Hook up the clutch pedal with feet. If it can be hooked up and the abnormal sound disappears, it can be judged that the pedal return spring is too soft, falling off or broken, so that the release bearing can not return to its original place and scratch the release lever.

② Check the release bearing for oil shortage. Press the clutch pedal a little to make the clutch bearing contact with the release lever, for example, the noise of “sand, sand” or “Shua, Shua” is heard, and the sound disappears when the pedal is released, indicating that the clutch bearing is lack of oil or damaged.

③ Listen beside the clutch. When the diesel engine is running at low speed, there is a non rhythmic sound of “clattering”. When the accelerator is increased, the sound is more serious. Open the inspection window of the clutch housing side cover, turn the diesel engine crankshaft, and observe whether the release lever is broken.

④ When just depressing the clutch pedal or just lifting the clutch pedal, there is a “click” knock, which may be caused by the loose rivets on the friction plate of the clutch driven plate, the loose rivets between the driven plate and the driven plate hub, or the worn and loose pin holes of the release lever and the pin shaft.

⑤ On board diagnosis. When the clutch pedal is pressed to the end, if the spline hole of the driven disc hub and the spline tooth of the clutch shaft are worn loose, there will be a “quack” impact sound.

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