CPCD60 forklift multi-way valve leakage troubleshooting

CPCD60 forklift truck is using the ZS series, multi-channel multi-way valve, the valve includes the housing, lifting the valve stem, tilt valve stem, the return spring, safety valve and cone valve and other components, the formation of the internal oil into the channel , Working oil way, oil return way, spillway way and total return way so that the hydraulic oil can flow in various oil passages under different working conditions to achieve different working purposes. The inlet valve has an inlet connected to the working pump of the system, the return port of the return valve is connected to the return port of the system, and the safety valve (overflow valve) controls the spillway. CPCD60 forklift hydraulic system rated pressure of 16Mpa, the flow rate of 160L / min. Oil leakage is the most common multi-way valve failure. 1, leakage within the multi-way valve leakage occurs, the working oil return channel or spillway connected to the oil, hydraulic oil directly back to the tank, unable to complete the operation, resulting in lifting hydraulic cylinder lifting or unable to lift , The fork sliding itself and mast forward lean failure. Reasons for internal leakage and troubleshooting are: (1) excessive wear and tear between the valve stem and valve body Road valve lift and tilt of the stem each have three grooves, groove and the oil channel can be connected Or cut off the oil, change the way of working. Good distribution valve stem and valve body gap between the small, minimal leakage, so the hydraulic cylinder down or tilt is small, does not affect the work. However, when the wear gap is too large, the pressure generated by the working oil pump will cause the oil in the working oil passage to communicate with the oil return passage or the oil spill passage and automatically return to the oil tank. The main reason is due to the long-term use of the distribution valve or oil, etc. to speed up the stem and body wear and tear, damage to the sealing surface, leading to oil spills. If the repair of the valve stem wear lighter, chrome polished stem; if the valve stem wear serious, you need to be replaced. (2) oil leakage between the body As the working oil, return oil, oil spillway runs through the three single-piece valve body, so tightness between the valve body requirements, body and body oil passage Between the installation of O-ring, the valve body bolted together, to seal the purpose. If the bolts have a different solid moment, the valve body may warp. If the valve body is damaged or the O-ring is worn or damaged during installation, the oil leakage will easily occur between the valve bodies under the action of the oil pressure. Repair, if the valve body damage is required grinding, replacement O-ring, and in accordance with the order and torque requirements to tighten the bolt. (3) safety valve Spring failure safety valve is used to adjust the system's working pressure, the pressure maintained within a certain range, to prevent overloading, hydraulic cylinder piston to the extreme position or other causes of damage to the hydraulic system components. Safety valve is mainly by the spring force of the steel ball pressure on the valve position to open, close the purpose. When the hydraulic pump output pressure exceeds the specified value, the pressure of high-pressure oil to overcome part of the high pressure oil through the relief valve spillway back to the tank. When the hydraulic pressure reaches the specified value, the spring presses the steel ball to the position of the valve under the pre-tightening force of the spring, and the safety valve is closed. If the safety valve spring failure, the hydraulic oil below the system pressure can force the ball away from the valve position into the spillway, resulting in leakage, the system failure. When repairing, the spring must be replaced, and then use the adjusting screw to adjust the spring pressure to the specified 14 Mpa. Adjust the distance from the center of load 600mm loading 7.5t cargo, when the goods appear to be non-starting lock with a locking nut, then the pressure is the pressure to be adjusted. (4) Multi-way reversing valve stem can not be reset. The stem return spring is installed on the lower end of the valve stem. When the stem is in the upper position or the lower position, the spring can be compressed. When there is no external force, the spring Rod quickly restored to its original position. If the stem can not be reset, the groove and the oil passage, it will have internal leakage. First, as the valve stem reset spring deformation or damage, reducing the elastic spring can not make the valve stem back to its original position, the spring must be replaced when the repair; Second, between the body and the valve stem is not clean, resulting in greater resistance to the stem Reset the difficulty, the repair must be cleaned within the multi-way valve to eliminate the resistance. (5) cone valve wear cone valve is used to prevent oil back. If the cone valve wear, the oil channel is not strict, it will return the hydraulic oil, the system failure. Repair, should be grinded or replaced. Eliminate backflow. 2, the valve body leaking oil stem and body seal by O-ring to achieve, if the ring aging or damage, under the pressure of the system will flow along the valve stem outflow of oil, leading to body leakage of oil. Only need to replace O-ring to eliminate this fault.