How not to affect the piston of the hydraulic cylinder

In order to prevent the piston from colliding with the cylinder head at both ends of the stroke, causing noise, affecting the accuracy of the workpiece and damaging the machine parts, buffer devices are often set at both ends of the hydraulic cylinder in the hydraulic pump station system. Its function is to use the throttling principle of oil to realize the braking of moving parts. The commonly used buffer device has three forms: annular clearance type, adjustable throttle port and variable throttle port.

Annular clearance type: when the buffer plunger enters the inner hole on its matching cylinder head, the hydraulic oil must pass through the clearance before being discharged, so that the piston speed is reduced. As the fitting clearance remains unchanged, the cushioning effect is not adjustable, and its cushioning effect gradually weakens with the decrease of piston speed.

Adjustable orifice: when the buffer plunger enters the inner hole on the cylinder head, the hydraulic oil must pass through the throttle valve before being discharged. Since the throttle valve is adjustable, the buffering effect is also adjustable, but this adjustment is the adjustment before buffering. During buffering, the buffering effect is still fixed.

Throttle port variable type: a triangular groove is opened in the axial direction of the piston, and its overflow section is becoming smaller and smaller, and the buffer effect is enhanced with the decrease of speed. The buffer effect is uniform, the buffer pressure is low, and the braking position accuracy is high, which solves the problem of too weak buffer effect in the post stroke stage.

Buffer device: clearance buffer, throttling buffer, axial triangle groove buffer.

About the exhaust of hydraulic cylinder in hydraulic pump station system. For long-term unused hydraulic cylinders or newly purchased hydraulic cylinders, air often accumulates in the high parts of the cylinder. The existence of air will make the hydraulic pump station system unstable, causing vibration or crawling. Therefore, the hydraulic cylinder should be equipped with an exhaust device.

There are usually two forms of exhaust devices: one is to open an exhaust hole at the high part of the hydraulic cylinder and use a long pipe to vent to the distant exhaust valve; The other is to install the exhaust valve directly at the high part of the cylinder head. For the hydraulic cylinder of the double acting hydraulic pump station system, two exhaust valves should be set.