The failure of hydraulic cylinder and its solution
1. The valve core is stuck or the valve hole is blocked. When the flow valve or directional valve spool is stuck or the valve hole is blocked, the hydraulic cylinder is prone to malfunction or malfunction. At this time, check the contamination of the oil; check whether dirt or colloidal deposits are stuck in the valve core or block the valve hole; check the wear of the valve body.
2. The piston rod and the cylinder are stuck or the hydraulic cylinder is blocked. At this time, no matter how you manipulate it, the hydraulic cylinder does not move or moves slightly. At this time, check whether the piston and piston rod seals are too tight, whether dirt and colloidal deposits have entered: whether the axis line of the piston rod and the cylinder barrel is aligned, and whether the wearing parts and seals are invalid.
3. The control pressure of the hydraulic system is too low. The throttling resistance in the control pipeline may be too large, the flow valve is improperly adjusted, the control pressure is inappropriate, and the pressure source is disturbed. At this time, check the control pressure source to ensure that the pressure is adjusted to the specified value of the system.
4. Air enters the hydraulic system. Mainly because there are leaks in the system. At this time, check the liquid level of the hydraulic oil tank, the seals and pipe joints on the suction side of the hydraulic pump, and whether the oil suction strainer is too dirty. If so, hydraulic oil should be added, seals and pipe joints should be treated, and the coarse filter element should be cleaned or replaced.
5. The initial movement of the hydraulic cylinder is slow. In the case of low temperature, the hydraulic oil has high viscosity and poor fluidity, which causes the hydraulic cylinder to move slowly. The improvement method is to replace the hydraulic oil with better viscosity and temperature performance. At low temperatures, it can be heated by a heater or the machine itself to increase the oil temperature at startup.
Basic structure of hydraulic cylinder
The main parts of the cylinder are cylinder head, cylinder head, cylinder cylinder, piston, piston rod, guide sleeve, seal and tie rod. Cylinder heads and cylinder heads are usually made of rolled steel or cast iron.The cylinder barrel is usually made of seamless steel pipe, and the inner hole is processed to a high surface finish, which can reduce the internal friction and extend the life of the seal. Pistons are mostly made of cast iron or steel, and several methods are used to fix the piston to the piston rod. Cushioning is an available option on most cylinders and can often be added without changing the outline size.Piston rods are generally high-strength steels that have been carburized and quenched, ground, polished, and plated with hard chromium for wear and corrosion resistance. Corrosive atmosphere conditions usually require stainless steel rods. The rod can be chrome plated for wear resistance. The guide sleeve is used to support the piston rod when it moves back and forth, most of which are made of ductile iron and usually can be removed without disassembling the entire cylinder.The rod sealing device usually includes a dust ring on the outside to remove dust and pollution from the rod. And to prevent being sucked in, a main seal is used to seal the cylinder pressure. The high pressure oil cylinder needs to add an oil pressure buffer ring before the main seal to reduce the oil pressure of the main seal ring and improve the sealing effect and life of the main seal ring.Tie rods are usually high-strength steel with cut or threaded threads. Prestressing with proper torque to prevent stress is to separate the parts and reduce the need for lock nuts, although lock nuts are sometimes used.