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How to assemble and disassemblethe hydraulic cylinder
2014-02-25 11:46:36

How to assemble and disassemblethe hydraulic cylinder

A complete hydraulic system consists of five parts, namely, power components, actuator components, control components, components and hydraulic oil. Power components are used to convert prime mover’s mechanical energy into hydraulic energy, which refers to the pump of the hydraulic system, and it provides power for the whole hydraulic system. Actuator components (such as hydraulic cylinders and hydraulic motors) are used to converthydraulic energy into mechanical energy, and drive the load to straight reciprocating-motion or rotary-motion. Control components(refers to the various hydraulic valves) are used to control and adjust hydraulic pressure, flow and direction in the hydraulic system. According to their different control functions,hydraulic valves can be divided to pressure control valves, flow control valves and direction control valves. And pressure control valve is divided intooverflow valve(safety valve), reducing valves, sequence valves, pressure relay etc;flow control valves including throttle valve, adjusting valves, flow distributing and collecting valves; directional control valves including the non-return valve, hydraulic-control non-return valves, shuttle valves and reversing valves, etc. According to different control ways, hydraulic valves can be divided into switching control valves, fixed-value control valves and proportional control valve. Auxiliary components including oil tank, oil filter, tube,joint, seal, pressure gauges, oil temperature gauge, etc.Hydraulic oil is the medium in hydraulic system working to pass energy, and it consists of several categories such as mineral oils, emulsion oil and synthetic hydraulic oil.

Assembly and disassembly of hydraulic cylinder

(1) Before disassembling hydraulic cylinders, the pressure of hydraulic circuit should be reduced. Otherwise, when the cylinders joints loosen, the hydraulic oil of the loop will be ejected rapidly.   The handwheel of the overflow valve should be loosen or adjusting screw when reducing the pressure, so that unloading oil pressure, then cut off the switch or the power to stop hydraulic device’s motion.

hydraulic cylinder

(2) Disassemblingshould prevent destroying the piston rod thread on the top,thread on the oil mouth, thread on the surface, and inner wall of cylinder. In order to prevent the slender piston rod bent or deformed, it should use the wood to make it balance when placing.

(3)Disassemblingin order. Due to various structure and size of hydraulic cylinder, the order of disassembling is also different. Generally, release oils hydraulic oils cylinder two cavities firstly, and then removing the cylinder head, and finally remove the piston and piston rod. When dismantling the cylinder heads, the special tool is need for the snap key and snapring in card-type join, and the flat spade is prohibited; as for flanged-type, it has to use a screw to let out the head, and the hammer or hard pry is not allowed. At the time of piston and rod to extract cannot be forced out, you should identify the reasons for the demolition.

(4) Disassembling should prevent hydraulic cylinder parts from polluting by dust and debris.   For example, the removal should be carried out in a clean environment as far as possible; after demolition of all the good parts are covered with plastic sheeting, and do not cover with cloth of cotton or other work.   

(5) Check carefully after finishing the disassembling,and classify parts to 3 classifications: useful parts, fix needed parts and the useless parts.   

(6) Clean the parts carefully before assembling.   

(7) Installing seals correctly.   

hydraulic cylinder head seal installation

① When installing the O-shape ring, please do not pull it to the point of permanent deformation, neither installing with ring rolling, otherwise it might be leaked because of the twisted shape.

②When installing Y -shape and V –shape ring , please pay attention to the mounting direction  to avoid leakage because of wrong direction . As for the Y –shape ring, its lips should cope with oil chamber with pressure; in addition, please distinguish the usage in shaft or hole of Yx –shape ring. V –shape ring consist of supporting ring, seal rings and pressure rings withdifferent size. If the pressure ring go wrong, the supporting ring will shape the seal ring to work for sealing, so the sealing ring should be installed for the opening of oil chamber with pressure;    the adjusting of the pressure ring should avoid leakage, but take care of high seal resistance because of over pressure.

hydraulic cylinder piston rod seal installation

③When the sealing device needs to be matched with the slip surface, please put some hydraulic oil on that .

④New O -shape ring seals and anti-dust rings should be used after disassembling .

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