The piston rod can be used in hydraulic and pneumatic systems, and its processing requirements are relatively high. Therefore, the quality of hydraulic cylinders is mostly influenced by the quality of the piston rod. When it can be used in hydraulic and pneumatic systems, its processing requirements are relatively high, so the quality of hydraulic cylinders is mostly influenced by the quality of the piston rod.
The piston rod is a connecting component that supports the piston to do work. It is mostly used in oil cylinders and cylinder motion execution components, and is a frequently moving and technically demanding moving component. Taking a hydraulic cylinder as an example, it consists of several parts: cylinder barrel, piston rod (cylinder rod), piston, and end cap. The quality of its processing directly affects the lifespan and reliability of the entire product. The processing requirements for piston rods are high, with a surface roughness requirement of Ra0.4-0.8um, and strict requirements for coaxiality and wear resistance.
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 air. In the piston rod packing, there are generally three clearances, namely: axial clearance: mainly used to ensure that the packing ring can float freely, otherwise the piston rod cannot work normally. Radial clearance: To avoid compression of the packing ring due to the sinking of the piston rod, in order to prevent deformation or damage.
The machining technology of piston rod is also an important part, and the quality of machining technology directly affects the quality and service life of the piston rod. The machining of piston rod is generally carried out by rolling, because this machining method can improve the corrosion resistance of the surface of the piston rod, delay the generation and expansion of fatigue cracks, and thus improve the fatigue strength of the piston rod.
From the perspective of design philosophy, the piston rod does not want to bear radial forces, but due to practical structural limitations, the piston rod of its hydraulic cylinder inevitably bears a considerable amount of radial external forces. For this reason, 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. To increase its guiding effect and increase the supporting surface area, thereby achieving the goal of reducing wear and improving the service life of hydraulic cylinders.
The quality of the hydraulic system largely depends on the quality of the piston rod, so the machining of the piston should require sufficient precision in form and position tolerances. Generally speaking, the roundness and cylindricity errors of the piston outer diameter and inner hole cannot exceed half of their dimensional tolerances; The coaxiality tolerance of the outer diameter of the piston rod to the inner hole and sealing groove should be within 0.02mm. Generally, it is required that the perpendicularity tolerance of the end face of the hydraulic cylinder to the axis of the hydraulic cylinder be less than 0.04mm/100mm.