In the course of long-term use, tractor hydraulic suspension system parts wear, deformation happens, hydraulic pipe will appear fatigue damage or fracture etc, lead to the hydraulic system of leakage, leakage, and jams, card lag phenomenon, resulting in hydraulic suspension system can not work well, a farm tools cannot ascend, operating mechanism failure and multi-way valve failure of failure.
Foam is rising at the oil port of hydraulic tubing
Tractor work from the hydraulic tank refueling port bubble, serious, hydraulic oil from the refueling port channeled.
The main reason is that there is air in the hydraulic system, resulting in air into the hydraulic system of the reasons and parts are: (1) gear pump drive shaft from tight oil seal is not tight or damaged, air from inhalation. (2) the oil suction mouth rubber ring damage, bolts loose, rubber tube clamp is not tight or tubing joint nut is not tightened, in the oil suction mouth vacuum, air is constantly sucked into the hydraulic system. (3) the oil outlet of the oil tank filter or filter blockage, in the role of the oil pump, oil absorption tank filter and pipeline formation of vacuum. A large amount of air is inhaled from the filter and pipe connections. (4) the hydraulic system work oil temperature is too low, oil pump running speed is too high, hydraulic fluid poor, forming a vacuum, breathing air.
Troubleshooting method: (1) replace the damaged self-tightening oil seal. (2) replace the oil suction nozzle apron, tighten the loose bolts, hose clamp and tubing joint nut. Clean mesh and filter. (4) before the hydraulic system into the operation, the first pretemperature, when the oil temperature in 30℃ above, then into the operation.
Farm tools cannot be promoted
When the control handle of the distributor is pushed to the "lifting" position, the farm tools cannot be lifted, and the distributor has a sound, or when the control handle is pushed to the "lifting" position, it immediately jumps back to the "neutral" position.
Cause farm tools can not be lifted, in addition to oil pump wear, distributor slide valve and seat wear, cylinder piston wear and other reasons, there are: (1) the power of the oil pump is not connected or the oil pump clutch joint is not good, the work of their own off or bolt broken. The tank is short of oil. When the lack of oil is less, the lifting of farm tools is slow; when the lack of oil is more, the lifting of farm tools is not at all. A certain safety valve in the hydraulic system is out of order. (4) cylinder positioning valve and positioning clamp gap adjustment is too small or no gap, resulting in positioning valve can not overcome the main cylinder piston rod bearing capacity and rise, make the oil road blocked.
Troubleshooting methods: (1) the first check whether the oil pump power is connected, is not easy to check the tractor, can flow by observing whether the hydraulic oil tank, the entire system determine whether there is a noise: if oil does not flow, no noise, engine load without any change, you can determine the oil pump power didn't get through, should the engine flameout, joint power again before you start the engine. (2) the cylinder positioning valve and positioning clamp clearance is too small or no clearance, it should be adjusted to the standard value. (3) the return oil valve is the debris pad up or stuck, can be used small wooden hammer percussion distributor return oil valve number, in order to its vibration fell back to the original position, such as the elimination, can remove the return oil valve with diesel cleaning.
3 hanging farm tools "nod"
After the lifting of farm tools, the engine does not turn off, the control handle of the hydraulic gear pump is placed in the joint position, the hanging farmer has a serious "nod" phenomenon, that is, the farm tools first slow down to a certain degree, and then quickly rise, continuous occurrence of the above action.
The reasons for the failure are as follows: (1) the sealing ring of the cylinder has defects or serious wear, so that the high-pressure oil leakage in the cylinder is serious. (2) distributor one-way valve between the ball and seat, due to the dirt pad or serious wear and seal is not tight, resulting in the cylinder of high pressure oil leakage. (3) from the hydraulic distributor to the cylinder of the high-pressure oil road, several O sealing ring, if one of the damage, or installation of sealing ring groove processing is out of line, resulting in high-pressure oil leakage. (4) the main control valve and the gap between the valve suite is too large, seal is not strict. (5) the cylinder safety valve assembly or installation parts of the sealing is not tight and leakage.
Troubleshooting method: in case of the above faults, check whether the installation is correct and whether the sealing ring is damaged. If the wear between the main control valve and the valve sleeve is serious and the clearance is too large, the original design clearance can be restored by re-matching and grinding after chrome-plating.
The operating mechanism fails
In the regulation of the tillage depth of the hydraulic suspension device, the position control handle pre-selects a specified height of the farm tool to the tractor, and the hydraulic suspension system will make the farm tool rise or fall to the specified position.
The handle is placed in the middle position between the lifts. When the hydraulic suspension is powered up, the farm tools go beyond their intended central position to a higher position, and the gear pumps continue to work, the safety valves open, the engine exhaust fumes, and the hydraulic system does not return to a neutral position. This fault appears to be the control mechanism failure, but the essence is the feedback mechanism error, tightening on the shaft of the CAM loose. When the lifting shaft turns, the adjusting CAM does not turn and cannot drop the lift of the CAM. The control end of the adjusting lever pushes the main control valve from the rising position to a neutral position. The hydraulic system is under load. To eliminate this fault, the output shaft separation control handle should be separated first, and then the main parts of the elevator to readjust, tight position adjustment CAM.
Multiple valve failure
The multi-way valve installed on the transport tractor can not lift or lift slowly when lifting the trailer compartment.
Fault reason: (1) body cavity dislocation. This is the casting process on the molding position error. Because the valve body is cast cavity, the position accuracy is low, and the axial coincidence degree when matching with the slide valve is poor, easy to produce dislocation. Reset spring failure. Using the multi-way valve reset spring for a long time, due to fatigue, plastic deformation and other reasons, so that the slide valve should not be to the position. (3) sand hole oil leakage. The casting sand hole of the valve body is some obvious, which is found and scrapped during processing. Some are more concealed, by the continuous impact of high pressure oil, sand hole expansion, oil leakage is serious, resulting in internal leakage. (4) slide valve and valve body wear, the gap between the slide valve and valve body increase, will cause internal leakage.
Exclusion method: for the oil channel dislocation, can be added to reduce the end of the spring of the slide valve pad thickness to make up for. Springs that have lost elasticity should be replaced. Body with sand holes can only be replaced if the sand holes are serious. The worn slide valve can be repaired by chrome plated grinding.
