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The fault diagnosis of hydraulic cylinder
Hydraulic cylinder hydraulic system is the hydraulic energy into mechanical energy of the executive element. The fault can be divided into the hydraulic cylinder malfunction, unable to drive the load and the sliding or crawling. Because of hydraulic cylinder malfunction caused It is often seen. equipment shutdown phenomenon, therefore, should pay attention to the fault diagnosis of hydraulic cylinder and the use of maintenance work.
าป Fault diagnosis and treatment 1 The mal operation or failure of actions There are several reasons and treatment methods:(1) Spool stuck valve plug hole. When the flow valve or valve spool stuck valve plug hole, hydraulic cylinder prone to malfunction or failure of actions. You should check the oil pollution level; check the dirt or gum deposit is jammed spool valve hole or blockage; wear check valve.
(2) The piston rod and the cylinder or hydraulic cylinder block. At this time in any case control, hydraulic cylinders are not little action. You should check the piston and piston rod sealing are too, whether to enter the dirt and gum deposit: axis of the piston rod and the cylinder are right, wearing parts and the seal failure.
(3) Control of hydraulic system pressure too low. Control throttle resistance line may be too large, the flow valve regulating improper, inappropriate control pressure, pressure source interference. You should check the control pressure source, pressure regulation to ensure system specified value.
(4) Into the air in the hydraulic system. Mainly because the system have leakage. You should check the level of the hydraulic oil tank, the seal and the pipe joint hydraulic pump suction side, the oil strainer is too dirty. If so, should add the hydraulic oil processing, sealing and pipe joints, clean or replace the coarse filter.
(5) The initial slow hydraulic cylinder. In the situation of low temperature, hydraulic oil viscosity, poor mobility, leading to the hydraulic cylinder moves slowly. To improve the method is replacing the hydraulic oil temperature, viscosity with good performance at low temperature by the heater, or use the machine to improve the startup self heating temperature.
2 Work can not drive the load Mainly for the piston rod stops, insufficient thrust, speed down, work is not stable because of the:(1) The internal leakage of hydraulic cylinder. The internal leakage of hydraulic cylinder comprises a hydraulic cylinder seal, piston rod and the sealing lid and piston seal are excessive wear caused by leakage.
The piston rod and the sealing cover seal leakage reason is, seals, extrusion, tearing, crease wear, aging, metamorphism, deformation, you should replace the new seal.
The main reason for the excessive wear of piston seal is speed control valve regulating improperly, causing high back pressure and seal installation is improper or hydraulic oil pollution. The second is a foreign body in the assembly and sealing material quality is not good. The result is slow, weak, can also cause serious damage to the piston and cylinder, appear "cylinder" phenomenon. Processing method is to adjust the speed control valve, control the installation instructions shall make the necessary operation and improvement; filter cleaning or replacement of filter, hydraulic oil.
(2) The hydraulic circuit leakage. Leak valve comprises a valve and hydraulic lines. Maintenance method is through the control valve check and eliminate hydraulic pipeline leakage.
(3) The hydraulic oil through an overflow valve bypass oil return tank. If the overflow valve into the dirt stuck valve, the overflow valve is normally open, hydraulic oil will directly back to the tank overflow valve bypass, resulting in no oil into the hydraulic cylinder. If the load is too large, adjust the pressure relief valve has reached the maximum ratings, but the hydraulic cylinder is not continuous action required thrust without action. If the pressure is low, due to insufficient pressure not up to still load required for vertebral force, thrust is not enough. You should check and adjust the relief valve.
3 The piston sliding or crawlingHydraulic cylinder piston sliding or crawling will make the work of the hydraulic cylinder is not stable. The main reasons are as follows:
(1) The hydraulic cylinder internal stagnation. Hydraulic cylinder internal parts of improper assembly, parts wear or deformation, shape and position tolerance limit, action resistance is too large, the hydraulic cylinder piston velocity varying with stroke in different position, slip or crawling. The reasons are mostly due to the poor quality of parts assembly, surface scars or sintering of iron filings, the resistance increases, rate of decline. For example: the piston and piston rod misalignment or piston rod bending, hydraulic cylinder or piston rod to the guide rail mounting position offset, sealing ring is arranged too tight or too loose. The solution is to re repair or adjustment, the replacement of the damaged parts and to remove iron.
(2) The bad lubrication or hydraulic cylinder aperture processing error. Because the piston and cylinder, and the piston rod guide rail has the relative motion, if poor lubrication or hydraulic cylinder diameter tolerance, will aggravate the wear, the straight cylinder centerline down. In this way, the piston in the hydraulic cylinder, the friction resistance can be big or small, slip or crawling. Elimination method is to grind the hydraulic cylinder, with the piston according to requirements, the grinding rod, configuration guide sleeve.
(3) Hydraulic pumps or hydraulic cylinder into the air. Air compression or expansion will cause the piston sliding or crawling. Exclusion measures to check the hydraulic pump, set up special exhaust unit, fast operation and several times the exhaust stroke.
(4) The seal quality and slip or directly related to crawl. The O shaped sealing ring used in low pressure, ring compared with U, due to higher surface pressure, the static and dynamic friction resistance difference, prone to slipping or crawling; U type sealing ring surface pressure increases as the pressure increases, while the sealing effect also increased, but the static and dynamic friction resistance difference larger, inner pressure increases, effect of rubber elasticity, because the contact resistance lip of the seal ring will be increased, tilting and lip elongate, also easy to cause the sliding or creeping, to prevent tipping can be used to support environmental protection to maintain its stability.
Chinabase Machinery is a group of manufacturing facilities, offering one-stop solution for mechanical power transmission products in China. We can supply a full-range of power transmission products, such as chains, sprockets and plate wheels, pulleys, gearboxes, motors, couplings,Rod end manufacturing, gears and racks. Our product range also covers locking assemblies (clamping elements/locking device), taper bushes, QD bushes, bolt-on hubs, torque limiters, shaft collars, motor bases and motor slides, chain detachers, chain guides, universal joint, rod ends and yokes.
Article tags: Rod end manufacturing,hydraulic cylinder,Power Transmission.
