Hydraulic cylinder is an actuator that converts hydraulic energy into mechanical energy in hydraulic system. It is an important part of hydraulic forming block making machine. Faults can basically be summarized as failure to drive load, hydraulic cylinder failure, piston slipping or creep. Due to the failure of hydraulic cylinder, the phenomenon of equipment shutdown is not uncommon. Therefore, attention should be paid to the fault diagnosis and maintenance of hydraulic cylinders. FULANG Machinery as a professional manufacturer of automatic brick machine, will provide you with the reference of this article.
1. Malfunction
The reasons and treatment methods are as follows:
(1) Plug blocking or hole blocking. When the flow valve or direction valve spool is stuck or the valve hole is blocked, the hydraulic cylinder is prone to failure or failure. In this case, check the oil contamination; check whether there is dirt or gelatinous sediment in the plug to block or plug the valve hole; check the wear of the valve body, clean and replace the system filters, clean the fuel tank, replace the hydraulic medium.
(2) Hydraulic system control pressure is too low. The throttling resistance of the control pipeline is too large, the flow valve is not adjusted properly, the control pressure is not appropriate, and the pressure source is disturbed. At this point, the control pressure source should be checked to ensure that the pressure is adjusted to the specified value of the system.
(3) The piston rod is jammed on the cylinder or the hydraulic cylinder. At this time, no matter how to operate, the hydraulic cylinder will not move or move slightly. At this point, check whether the piston and piston rod seals are too tight, whether they enter dirt and gelatinous deposits: whether the axis of piston rod and cylinder is in the middle, whether the vulnerable parts and seals are invalid, whether the load is too large.
(4) Initial movement of hydraulic cylinder is slow. At low temperature, the high viscosity and poor fluidity of hydraulic oil result in slow motion of hydraulic cylinder. The improved method is to replace hydraulic oil with better viscosity and temperature performance. At low temperatures, the heater can be heated by the heater or the machine itself to increase the oil temperature during start-up. The normal working oil temperature of the system should be kept at about 40 degree C.
(5) Air entering the hydraulic system. Mainly because of system leakage. In this case, check the level of the hydraulic tank, the seals and fittings on the suction side of the hydraulic pump, and whether the suction filter is too dirty. If so, add hydraulic oil, handle seals and joints, and clean or replace coarse filters.
2. Can not drive the load when working
The main performance is that the piston rod is not in place, the thrust is insufficient, the speed is slow and the work is unstable, when the hydraulic concrete block machine is working. As a result of:
(1) Internal leakage of hydraulic cylinder. Internal leakage of hydraulic cylinder includes leakage caused by hydraulic cylinder seal, piston rod and seal cap seal, and excessive wear of piston seal.
The reasons for leakage of piston rod and seal cover are wrinkling, crushing, tearing, wear, aging, deterioration and deformation of seal parts. At this time, new seals should be replaced.
The main reasons for excessive wear of piston seals are improper adjustment of speed control valves, resulting in excessive back pressure, improper sealing installation or hydraulic oil pollution. Second, foreign bodies enter the assembly process, and the quality of sealing materials is not good. The consequence is that the action is slow and weak. When the piston and cylinder are damaged seriously, the phenomenon of “pulling cylinder” appears. The treatment method is to adjust the speed regulating valve and make necessary operation and improvement according to the installation instructions.
(2) Hydraulic oil passes through relief valve bypass to tank. If the relief valve enters the dirt, the plug closes, the relief valve opens normally, and the hydraulic oil flows back to the tank through the relief valve bypass, resulting in no oil entering the hydraulic cylinder. If the load is too large, the regulating pressure of the safety valve has reached the maximum rated value, but the hydraulic cylinder still can not obtain the thrust required for continuous operation without action. If the adjustment pressure is low, the pressure is not enough to achieve the required force and thrust is insufficient. The safety valve should be checked and adjusted at this time.
(3) Leakage of hydraulic circuit. Includes leakage of valves and hydraulic pipes. The inspection method is to check and eliminate the leakage of the hydraulic connection pipeline by operating the reversing valve.
3. The piston slips or crawls
Sliding or crawling of the hydraulic cylinder piston will make the hydraulic cylinder unstable when you using automatic brick manufacturing machine. The main reasons are as follows:
(1) Poor lubrication or excessive processing of cylinder bores. Because the piston and cylinder, guide rail and piston rod have relative motion, if the lubrication is not good or the bore is too bad, the wear will be aggravated, and the straightness of the cylinder center line will be reduced. Therefore, when the piston works in the hydraulic cylinder, the friction resistance will be large and small, leading to sliding or crawling. The solution is to grind the hydraulic cylinder first, then prepare the piston as required, repair the piston rod, and install the guide sleeve.
(2) The internal pressure of the hydraulic cylinder is stagnant. The internal parts of the hydraulic cylinder are improperly assembled, the parts are deformed, worn or geometric tolerances exceed the standard, and the movement resistance is too large, which makes the piston speed of the hydraulic cylinder change with the travel position and causes slippage or creep. The main reasons are poor assembly quality, surface scratches or sintered iron chips, which increase resistance and reduce speed. For example, the piston and piston rod are not centric or the piston rod is bent, the hydraulic cylinder or piston rod deviates from the track installation position, and the sealing ring is too tight or too loose. The solution is to repair or adjust, replace damaged parts and remove iron chips.
(3) The quality of seal is directly related to sliding or creep. When O-ring is used at low pressure, compared with U-ring seal, the surface pressure of O-ring is higher, the difference of dynamic and static friction resistance is larger, and it is easy to slip or creep. The surface pressure of U-ring increases with the increase of pressure. However, although the sealing effect has been improved correspondingly, the difference between the dynamic and static friction resistance increases, the internal pressure increases, and the elasticity of rubber is affected. With the increase of lip contact resistance, the seal ring will turn over and the lip will be elongated. It is also prone to slip or crawl, and support rings can be used to keep it stable to prevent it from overturning.
(4) Hydraulic pumps or cylinders enter the air. Compressed or expanded air can cause the piston to slide or crawl. Pay attention to check the hydraulic pump, set up a special exhaust device, fast operation exhaust several times.
If you have any interest about the fly ash bricks manufacturing plant, FULANG MACHINE shall provide you more professional information.