Analysis and treatment of impact failure of hydraulic cylinder
- No buffering device is provided. Treatment method: adjust the reversing time (>0.2 seconds), reduce the power speed of the hydraulic cylinder; add a buffering device.
- The gap between the plunger and the hole in the buffer device is too large. Treatment method: replace the slow plunger or insert a sleeve in the hole, and the gap will meet the specified requirements; check the throttle valve.
- The one-way valve with a buffer at the end is reversed. Treatment method: repair, research and match the one-way valve and valve seat or replace it. The gas-liquid pressurized cylinder has fast action speed, stable transmission, simple cylinder device, easy output adjustment, low energy consumption, soft landing without damaging the mold, easy installation, small space occupation, less failure, long life, and low noise.
Analysis and treatment of external leakage failure of hydraulic cylinder
(1). Piston rod surface damage, treatment method: repair the piston rod damage.
(2), the edge of the sealing ring is damaged or aging, the treatment method: replace the sealing ring.
(3) The pipe joint is not tightly sealed, and the treatment method: check the sealing ring and contact surface for scratches, repair or replace it.
(4) The cylinder head is not tightly sealed, and the treatment method: inspect the machining accuracy of the contact surface and the aging of the sealing ring, and replace or repair it in time.
(5). Due to poor exhaust, the adiabatic compression of the gas causes local high temperature and damages the sealing ring. Treatment method: check the exhaust device, or add an exhaust device; exhaust in time.
(6) The sealing of the buffer device is not tight, and the treatment method: the machining accuracy (precision) of the contact surface of the cylinder rod and the aging condition of the sealing ring should be replaced or repaired in time.
Analysis and treatment of internal leakage failure of hydraulic cylinder
(1) The fit gap between the cylinder bore and the piston is increased due to wear and out of tolerance. Treatment method: When the piston is worn seriously, the cylinder bore should be bored, the piston should be small, and the several grooves of the car should be equipped with seals or new pistons. .
(2). The seal ring on the piston is worn or aged. Treatment method: the seal ring should be replaced in time if it is worn or aged.
(3). Piston and cylinder barrel are installed out of concentricity or bear eccentric load to make the piston inclined or eccentrically worn. Treatment method: check the concentricity of cylinder barrel and piston and cylinder head piston rod hole, and trim the center.
(4). Poor straightness of the cylinder bore diameter or local wear caused by local waist drum boring cylinder bore. Treatment method: refit the piston.
Sound and noise
The air in the lower part of the piston is adiabaticly compressed. Processing method: move the piston slowly and reciprocate several times, each time to the top to remove the gas in the cylinder, this serious noise can be eliminated and the seal ring can be prevented from being burned.
Hydraulic control valve
The hydraulic control valve is the control and adjustment element in the hydraulic transmission system. It controls the direction, pressure and flow of the oil flow to meet the pressure, direction and speed requirements of the actuator, so that the actuator can drive the load to achieve a predetermined action . The speed is faster, the output is stable, the device is simple, the adjustment is easy, the maintenance is convenient, the output is large, and the output can reach the high output of oil pressure, and the power source is convenient. Low operating noise, no disturbance of oil pressure system heating up.
Performance requirements of hydraulic valves
In the hydraulic system, the performance requirements of the hydraulic valve mainly have the following points.
- The action is sensitive, reliable in use, the impact and vibration during work should be small, and the service life should be long.
- When the oil flows through the hydraulic pressure, the pressure loss should be small, the sealing performance should be good, the internal leakage should be small, and no external leakage.
- Compact structure, convenient installation, maintenance and adjustment, and good versatility.
Hydraulic valve classification
- Pressure control valve (referred to as pressure valve). It is used to control the pressure in the hydraulic system to meet the requirements of the force (or torque) required by the actuator. Including overflow valve, pressure reducing valve, sequence valve, pressure relay, etc.
- Directional control valve (referred to as directional valve). It is used to control the direction of oil in the hydraulic system to meet the requirements of the movement direction of the actuator. Including one-way valves, reversing valves, etc.
- Flow control valve (referred to as flow valve). It is used to control the flow in the hydraulic system to meet the requirements of the movement speed of the actuator. Including throttle valve, speed control valve, etc.
- Compound valve (also called multi-element valve). It is used to control two or all of the three parameters of direction, pressure, and flow in the hydraulic system. For example, a one-way pressure reducing valve can not only control the direction of the oil, but also control the pressure of the oil.
Analysis and Treatment of Common Faults of Overflow Valves
The hydraulic valve takes the overflow valve as an example, a brief introduction.
- There is a problem with the regulating device of the overflow valve. Treatment method: disassemble and inspect, and replace with a suitable pressure regulating spring.
- The spool of the solenoid directional valve is stuck. After energizing, the electromagnetic force cannot make the spool switch in place, so that the valve port has a slight opening. Treatment method: disassemble, inspect, clean, and grind the solenoid valve core.
- The poppet spool of the pilot valve of the relief valve is defective.
- Approach: Disassemble and inspect, and grind the sealing surface of the cone valve core. When the damage is serious, replace with new qualified parts.
- Disassemble, clean and check the degree of contamination of the hydraulic oil, filter the oil or change the oil according to the situation.
- The valve core of the electromagnetic valve in the relief valve is severely worn and internal leakage is aggravated. Treatment method: disassemble and inspect, clean hydraulic components and systems, eliminate factors that cause abnormal wear of hydraulic components, and replace with new reversing valves.
- The spool of the solenoid directional valve in the relief valve is seriously worn and internal leakage is aggravated. Treatment method: disassemble and inspect, clean hydraulic components and systems, eliminate factors that cause abnormal wear of hydraulic components, and then replace with new reversing valves.
- The main valve is faulty. Treatment method: disassemble and inspect, clean and trim the valve core and valve hole. If necessary, check the oil contamination, filter or replace the oil, and pay attention to maintaining the concentricity of the valve core and the valve hole during assembly.