Gearbox is one of the important transmission part of machine of wheel loader, which is responsible for the transmission of the motor speed and torque for the coming final drive system, change the transmission between the engine and the wheels of the ratio of loading machine, forward and reverse gear control, and can be implemented in the engine operating conditions to cut off the transmission power walking device in order to adapt to the loader, and the needs of driving, convenient starting and stopping safety engine. But in the loader working process, due to improper use and maintenance of gearbox fault caused the rate has been high, especially in use do not strictly comply with repair and maintenance procedures, the lack of timely inspection and maintenance, formation of gearbox damage and accelerate the failure, harm even expand fault consequences.
A, preventive maintenance purposes 1, through the tracking inspection on the loader operation, planned downtime, make gearbox maintenance and repair schedule.
2, to prevent the main mechanical failure and associated parts damage, failure in germination before it can repair, to save repair cost. 3, the components of the complete machine has long service life, improve equipment efficiency, maintain good working performance..
4, reduce repair difficulty and workload. The common faults and causes two, wheel loader gearbox 1, gear, not smoothly into the gear. Reasons: (1) the pressure valve pressure too low; (2) the hydraulic pump to work bad, bad sealing; (3) the hydraulic pipeline jam; (4) the clutch seal damage, leakage; (5) the gear stem is not in place. 2, gearbox, gear do not take off. Reasons: (1) the piston ring expansion; (2) the clutch friction plate burning; (3) the clutch return spring failure or damage; (4) the oil return pipeline blockage. 3, has been in gear, but the loader operation fatigue, can't even walk. Reasons: (1) friction wear, the gap is too large; (2) the clutch automatic emptying valve seal is not strict, so that the pressure drop; (3) shift control valve pipeline jam; (4) the shut-off valve can not return; (5) variable valve positioning spring fatigue or broken, the ball beating; (6) the clutch piston ring, the sealing ring wear serious, make a serious leak. 4, operating pressure too low. Reasons: (1) the transmission oil pan oil shortage; (2) the main oil spill; (3) transmission filter clogging; (4) the steering pump (or pump) damage, resulting in serious leakage; (5) transmission pressure regulating valve improper pressure adjustment; (6) the gear pressure valve spring failure or broken.
5, the automatic transmission retaining or out of gear. Reasons: (1) shift control valve positioning device failure, the main cause of failure is a positioning steel ball wear serious, or spring failure;
(2) the shift lever due to long-term use, location, length of the bar to change, member proportion is not accurate, the operation position deviation, resulting in dislocation. Three, how to carry on the gearbox preventive maintenance 1, according to JB/Z19483, combined with the actual repair and maintenance, shall comply with the following provisions:
(1) the daily maintenance: check oil level low shell; (2) 50 hours (or week): check the transmission control lever is flexible and effective; (3) 250 hours (it was only in the first 250 hours after work): cleaning gearbox oil pan and transmission oil filter element;
(4): 500 hours cleaning the oil pan filter, replace the gearbox oil; (5): 2000 hours of transmission, torque converter inspection maintenance. 2, hydraulic transmission oil is the carrier of energy transmission work, in hydraulic transmission system, the working fluid pressure, temperature and flow rate are decided by the transmission can work normally, so in the gearbox of the daily maintenance work, special attention should be paid to the hydraulic transmission oil inspection and replacement.
(1) fixed oil change intervals Oil in the correct time interval, make gearbox parts for long working life is. Only to ensure that a reasonable oil change intervals, to play the lubrication and protection characteristics of lubricating oil. Under normal circumstances should be based on the complete machine manufacturers recommended maintenance cycle as the basis, but it can only be relative, must analyze and oil extraction results are combined, can know the actual working conditions. For example, maintenance manual for gearbox oil change interval is 500h, we according to the loading machine operation, every 250h or 100h for a sample analysis of oil samples, to decide when to change, but the use of lubricating oil should be replaced immediately to 1000h.
In addition to the new oil changed regularly, in the usual checks, such as discovery of oil deterioration or mixed with impurities, should also be cleaning check and replace the oil, new.
(2) the row, the correct method of oil Put the oil, the oil temperature should reach 40 to 50 DEG C, and oil flow shall be discharged in stirring condition, as far as possible to completely emptying the dirty oil; gas, should use the tanker with a filtering device to add oil. (3) using the transmission system of the correct oil, lubricating oil and gearbox used must conform to the standard. It should be noted that, not the diesel engine oil added to the gear box, because the engine oil will decrease the friction between piston and other moving parts, while the transmission oil is to make the friction between certain friction force in combination, the friction force is crucial for normal operation of transmission system. Only the correct use of lubrication oil, can effectively extend the service life of the clutch friction plate. At the same time, the correct oil, can obviously improve the gear wear resistance, eliminate the clutch slipping control brake, shaking and noise, increase the braking force, provide greater traction. At present, the gearbox to use hydraulic transmission oil up to No. 6, No. 8 hydraulic transmission oil. (4) replace the filter cycle reference repair manual provides timely, replace the filter, at the same time cleaning filter, oil drain plug, magnet porous plugs, according to the standard amount of lubricating oil. If the viscosity gear oil is too large, will cause the transmission efficiency is low, liquidity is not good, bad heat dissipation, and the possible partial dry friction, between the high-speed relative motion components adverse lubrication; if the viscosity gear oil is too small, can increase the amount of leakage, resulting in gearbox control oil pressure is too low, the formation of fault, oil film strength between the transmission parts with larger load is not enough, early wear caused by transmission parts, thus unfavorable lubrication.
At the same time, the gearbox in the normal work because the oil stirring gear will have small bubble, in order to prevent bubbles accumulate, resulting in cavitation phenomenon, cause the oil film thickness decreases thus affecting the internal transmission clutch and the control valve, the gearbox oil must have the characteristic of anti foaming.
Therefore, the gearbox appropriate oil, can protect the gearbox, prolong the service life, reduce the transmission gearbox fault rate, direct cost but also can reduce the transmission oil maintenance and reduce gearbox maintenance manual and maintenance of parking time.
(5) all kinds of lubricating oil must be pure, and after a period of precipitation, in accordance with the quality requirements. ? gas tools, containers and the oiling mouth should be scrubbed clean, prevent moisture and dirt into the oil. Check the oil the vehicle must be in the longitudinal and transverse is in a level state.
Gas, oil, you must check whether there is leakage. Therefore, strengthens to the gearbox fault prevention and daily maintenance in daily use process is very necessary, which can not only reduce the work efficiency is low, because downtime caused by delays in time, but also can prevent and avoid greater subsequent failure, reduce the cost of repair, improve the security of the machine.