Causes and solutions of poor running performance of BMW roller

Today I will explain why the walking performance of BMW roller is poor and how to solve it

(1) check and eliminate the factors outside the hydraulic system, the engine speed should be 2300r/min, if not normal to exclude engine failure 3 manual control mechanism if wear, or replace the cable plug on solenoid valve 2 off should be repaired, the joystick or the switch in the corresponding position, measured with a multimeter the plug voltage, if the voltage is abnormal, troubleshooting of electrical control.

(2) check the hydraulic driving system of the main circuit of high pressure and oil supply pressure; 60MPa A and B in the high pressure port is connected with the oil pressure gauge, 6MPa connected in fill oil pressure and oil pressure. At normal temperature, oil supply pressure is 2.6MPa, pressure is 42MPa; such as hydraulic fill force and pressure are normal for mechanical failure; such as oil supply pressure is not normal to the (3) examination; such as fill oil pressure, normal pressure is not normal, then the (4) check.

(3) adjust the relief valve 7 when the walking lever is in middle position, if the oil pressure is still not normal, then check the overflow valve 7 to see whether the spring is broken and the valve core is stuck. If there is no abnormality, the fault of the oil pump is added

(4) measuring the motor leakage, remove the drain pipe in the motor, the motor is connected with a drain line at the tank, under the pressure of 20MPa, the amount of leakage of the rolling wheel drive motor should be less than 2L/min, the leakage should be less than 5L/min after the bridge drive motor, such as leakage is too large to replace or repair the motor.

(5) check the pump cavity (shell) pressure: at the pressure port R, connect the 1MPa oil pressure gauge, the normal pressure should be no more than 0.3MPa, abnormal, then check the oil drain pipe, replace the control components

(6) check the pressure relief valve 9 and two safety valve 6, if there is spring break or spool stuck, then replace or repair

(7) check the regulator control chamber pressure: release X3 and X4 plug, plug in the 6MPa oil pressure gauge, were observed in the two table of pressure in the forward and reverse, the normal pressure is about 2.6MPa. such as normal pressure, is walking pump 1 fault; if the pressure is not normal, but also for the next examination.

(8) check regulator control chamber orifice spray: X1 and X2 respectively, loosen the screw, observe the orifice spray, spray cleaning if adverse orifice.