The piston rod can be used in hydraulics and pneumatics, and its processing requirements are relatively high, so the quality of hydraulic cylinders is mostly affected by the quality of the piston rods. It can be used in hydraulics and pneumatics, and its processing requirements are relatively high, so hydraulic cylinders The quality of the piston rod is mostly affected by the quality of the piston rod.
The piston rod is the connecting part that supports the work of the piston. Most of it is used in the oil cylinder and the cylinder motion execution part. It is a moving part with frequent movements and high technical requirements. Taking the hydraulic cylinder as an example, it is composed of: cylinder barrel, piston rod (cylinder rod), piston, and end cover. The quality of its processing directly affects the life and reliability of the entire product. The piston rod has high processing requirements, and its surface roughness is required to be Ra0.4 ~ 0.8um, and the requirements for coaxiality and wear resistance are strict.
The main function of the piston rod packing ring is to seal the gap between the cylinder seat and the piston rod, which can prevent the piston rod from leaking. In the piston rod packing, there are generally three gaps, namely: axial Clearance: It is mainly used to ensure that the packing ring can float freely, otherwise the piston rod cannot work normally. Radial clearance: Avoid the compression of the packing ring due to the sinking of the piston rod, so as to avoid deformation or damage.
The processing technology of the piston rod is also a very important part. The quality of the processing technology will directly affect the quality and service life of the piston rod. The processing of the piston rod is generally carried out by rolling, because this processing method can Improve the corrosion resistance of the surface of the piston rod, delay the generation and expansion of fatigue cracks, thereby improving the fatigue strength of the piston rod.
Considering the design idea, the piston rod does not want to bear radial force, but due to the limitation of the actual structure, the piston rod of the hydraulic cylinder inevitably bears a considerable part of the radial external force. To this end, the length of the hydraulic cylinder piston must be appropriate, generally taking 0.7 to 1.0 times the outer diameter of the piston rod. In order to increase its guiding effect and increase the bearing surface area, so as to achieve the purpose of reducing wear and improving the service life of the hydraulic cylinder.
The quality of the hydraulic line depends to a large extent on the quality of the piston rod, so the machining of the piston should require sufficient geometric tolerances. Generally speaking, the error of the outer diameter of the piston, the roundness of the inner hole and the cylindricity should not be greater than half of its dimensional tolerance; the tolerance of the outer diameter of the piston rod to the inner hole and the concentricity of the sealing groove should be within 0.02mm. It is generally required that the verticality tolerance of the end of the hydraulic cylinder to the axis of the hydraulic cylinder should be less than 0.04mm/100mm.