Faults often appear in the transmission system during the operation of the loader. The LT956 loader produced by Xiamen Liteng Engineering Machinery Co., Ltd. is used as an example for fault analysis and repair.
1 One gear is weak or unable to walk, other gears are normal
Weakness or inability to walk means that the speed at which a gear is engaged is significantly lower than the normal speed at which the gear is in motion, or the bucket is not allowed to walk after being slightly pierced into the pile.
Liteng loader repair
If a certain gear is weak or incapable of walking, it can eliminate the problem of sharing the oil circuit and components of the torque converter, walking pump, pressure reducing valve and other gears. The location of the fault can only be after the shift control valve to the gear clutch piston Between the oil roads. At this moment, the main drive shaft rotation between the torque converter and the gearbox should be investigated first: when the gear is engaged, the main drive shaft continues to roll and the gearbox output shaft does not rotate after the bucket stabs the feeder Liteng loader to stop traveling. At this time, you can admit that the following problems exist:
(1) The bearing cover or nylon sleeve of the corresponding gear clutch is severely worn;
(2) If the bearing cover or nylon sleeve is outstanding or wears slightly, it indicates that the sealing ring on the front and back of the block clutch is not well sealed. After the weak parts such as bearing caps, nylon sleeves, front and back seal rings wear out, a lot of the oil supplied to the clutch leaks from the worn parts, and then the control oil pressure drops, and the clutch shows a slip phenomenon. Such problems are often accompanied by the phenomenon of excessive oil temperature .
Sweeping method: replace the corresponding damaged parts, that is, the bearing cover or nylon sleeve, the front and back sealing rings, adjust the bearing and bearing cover from the beginning, so that the bearing gap is 0.05-0.09mm. If the slipping time is too long, the friction plate may be burnt, and it should be replaced with a new one. If the oil is contaminated, the filter element screen should be cleaned or replaced with new oil.
2 The engine is normal, and you can't walk or can't walk in any gear
Each gear can't go or can't walk, and the fault range can be limited to the common oil circuit and components of the torque converter, walking pump, pressure reducing valve and other gears. When presenting such a problem, it can be investigated that the main drive shaft does not roll even when the whole machine cannot be moved.
Regarding this kind of problem, first check whether the hydraulic oil in the gearbox is satisfied. The method is to make the engine at idle speed. The oil level should be investigated in the middle of the oil mark next to the gearbox. If the oil level is not visible, make up the oil. After the oil level is normal, the difference is whether it appears suddenly or gradually. In case of sudden problems, the pressure relief valve should be dismantled and inspected to see if the surface of the valve core is scratched and stuck in the minimum oil supply position. You can check whether the spline of the walking pump connection sleeve is damaged by cleaning and grinding; Slowly presented, generally attributed to the gradual wear of walking parts or poor cleanliness of the oil, can be viewed in the following order:
(1) Determine whether the fault is in the torque converter. Check the mechanical oil return filter on the rear frame of the car. If there is a lot of aluminum dust attached to the filter screen, it can be concluded that the inner bearing of the torque converter is damaged and the "three wheels" are worn. The torque converter should be disassembled and replaced. Damaged parts and clean the oil circuit.
During the operation, the transmission oil in the working oil chamber of the torque converter must maintain the overflow condition. Insufficient oil will cause the output torque to drop, making the main transmission shaft unable to rotate or stop rotating. When checking, disconnect the low-pressure hose from the torque converter to the transmission (torque converter overflow) low pressure hose, and investigate the overflow flow of the oil return pipe under the idling condition of the engine. Under normal conditions, as long as there is little flow, the flow will suddenly increase when the engine speed increases and the relief valve in the torque converter pressure relief valve opens suddenly. If this flow rate is also large when the engine is idling, it can be concluded that the seal ring in the torque converter is severely worn, causing internal leakage.
(2) If the oil return from the torque converter to the gearbox is normal, run the engine at high speed. If the amount of oil return is small, check whether there is a dirty blockage or air leakage in the oil suction line of the walking pump. First check whether the oil absorption filter and walking pump hose in the gearbox are aging, whether they are dropped or bent inside.
(3) If the above is normal and it can be concluded that the volumetric power of the walking pump is low, replace the walking pump.
(4) Weakness of walking generally does not consider the oil return and cooling circuit of torque converter.
3 Need to move actively in neutral gear, normal gear can also be advanced when the gear is engaged, the Liteng loader can not walk when the gear is engaged or withdrawn, but the operating pressure of each gear is normal
One, three, two or four gear operation levers are in any gear, the travel and retraction operation levers are in the center position and the Liteng loader is traveling, which clarifies that the travel clutch is in the engaged state. After the retreating gear is engaged, the traveling clutch is not normally disengaged because the retreating clutch is engaged, the two clutches are in the engaged state at the same time, and then the phenomenon that the whole machine cannot go is formed. In this regard, the traveling clutch should be disassembled for inspection. Generally, the clutch master and follower plates are sintered and locked, or part of the circlip is pulled out, which causes the friction plate to skew and cannot be reset. In addition, the stuck piston of the traveling clutch and the blocking of the check valve of the support can also cause the clutch to move slowly or not. The jamming of the check valve is generally related to the cleanliness of the oil in the walking system. If necessary, clean the filter element and replace the hydraulic oil.
