Friction plate slips
(1) Failure phenomenon
This fault is manifested in the situation that when the forklift is starting, the engine power cannot be completely transmitted to the transmission after the clutch pedal is completely released, resulting in insufficient power of the forklift, difficulty in starting, and increased fuel consumption. When the forklift is stalled on a slope, it will automatically slide down after being engaged in a low-speed gear. It is difficult for forklifts to load uphill. In severe cases, a burnt smell will be emitted from the clutch.
(2) Cause analysis
There are 6 reasons for this failure: First, the clutch pedal has no free stroke, and the release bearing has been pressed on the release lever, making the clutch pressure plate in a semi-released state. The second is the oil stains on the friction plate; the third is the friction plate wear exceeds the limit (the friction plate rivet head is less than 0.5mm from the friction plate surface) or is severely ablated or damaged; the fourth is the pressure plate spring is too soft or broken; the fifth is the clutch pressure The fixing bolts of the disc and the flywheel are loose, or a gasket is installed between the pressure plate and the flywheel (at the connecting bolt); sixth, the clutch release bearing seat is stuck.
(3) Investigation examples
A JJCC forklift had difficulty starting in gear. As the engine throttle increased, a burnt smell was emitted from the clutch. Check that the clearance between the separation lever and the separation bearing is normal, and the thickness of the friction plate is normal. When the clutch pedal is stepped on, the friction plate can be separated normally. Continue to check that there is a gasket between the clutch pressure plate and the flywheel. When the clutch pedal is lifted, the friction plate can be pushed with a flat screwdriver, which indicates that the friction plate is in a semi-engaged and semi-detached state. Analysis believes that due to the installation of a gasket between the pressure plate and the flywheel, the pressure plate is not enough to press against the friction plate, resulting in slippage between the friction plate, flywheel and pressure plate, and a burnt smell is emitted. After removing the gasket and adjusting the gap between the separation lever and the separation bearing, the machine was tested, and the malfunction disappeared.
Incomplete separation
(1) Failure phenomenon
The fault is manifested as difficulty in gear shifting when the clutch pedal is depressed to the end when the forklift starts, and there is a clear noise in the transmission. After forcibly shifting into gear, without releasing the clutch pedal, the forklift can drive forward or cause the engine to stall. Depressing the clutch pedal, the forklift still cannot stop normally, and the shift lever is not easy to get out of the gear.
(2) Cause analysis
There are 4 reasons for this failure: one is that the free stroke of the clutch pedal is too large (more than 20~30mm); the other is that the height of the three separation levers is inconsistent (the error is greater than 0.40mm). Third, the friction plate warps, the rivets fall off, the new friction plate is too thick, and the friction plate is installed reversely (the front and rear lengths of the friction plate spline sleeve are different, the long side should face the flywheel, and the short side should face the transmission); the fourth is a separation lever Or the adjusting screw is broken; Fifth, the hydraulic clutch oil circuit failure, such as air or lack of oil, damage to the master cylinder and the sub-cylinder, etc.
(3) Investigation examples
A JJCC forklift is difficult to gear, and the engine will stall after gearing. After inspection, it was found that the release bearing and clutch pressure plate were ablated. After replacing the release bearing and pressure plate, and re-adjusting the clutch clearance, the forklift worked normally. A few days later, the release bearing was ablated again. When it was disassembled again, it was found that there was a deep groove on the journal of the transmission I shaft bearing cap. The analysis believes that whenever the clutch pedal is stepped on, the release bearing seat is stuck in the groove, causing the release bearing to press on the clutch release lever, causing the release bearing to rotate normally, causing the release bearing to be quickly ablated. After replacing the bearing cap of the transmission I shaft, the failure phenomenon disappeared.
