What are the common cushion methods in hydraulic cylinder?

When the mass of the moving parts is large and the movement speed is high, the significant inertial force generates substantial momentum. As a result, when the piston reaches the end of the cylinder, it mechanically collides with the end cover, creating strong impact and noise. This severely compromises mechanical accuracy. Therefore, in large, high-speed or high-precision hydraulic equipment, buffer devices must be set up.

The working principle of the hydraulic cylinder cushioning device is as follows: When the piston approaches the end of its stroke, the cylinder tube encloses a portion of the oil between the piston and the end cap. This forces the oil to pass through a small orifice or a narrow gap, creating significant backpressure. As a result, the moving parts experience braking resistance, gradually decelerating to prevent a collision between the piston and the end cap.

Commonly used cushioning devices include: Annular gap cushioning device, Orifice-type variable cushioning device, Orifice-type adjustable cushioning device.

The principle of annular gap cushioning :When the piston approaches the end of its stroke, the buffer plunger enters the cylinder head's bore, forcing the hydraulic oil to discharge through a fixed clearance. This creates a throttling effect that decelerates the piston. However, this cushioning effect is non-adjustable, and its effectiveness gradually diminishes as the piston speed decreases. This design is suitable for low-speed and light-load applications.

The principle of orifice-type variable cushioning: The piston is designed with axial triangular grooves. As the piston moves, the flow cross-section gradually decreases, causing buffer pressure to increase uniformly and enabling high braking precision. Unlike fixed cushioning systems, this design's effectiveness increases as speed decreases, effectively resolving end-stroke cushioning insufficiency. It is particularly suitable for high-speed or high-precision applications.

The principle of orifice-type adjustable cushioning: This cushioning mechanism utilizes an adjustable orifice to control hydraulic oil discharge during piston deceleration. This adjustable orifice cushioning system is designed for medium-speed applications and moderate loads. While it offers convenient pre-set adjustment capability through manual orifice configuration, the cushioning effect remains fixed during operation without dynamic modulation.

TOLENG is a manufacturer of hydraulic cylinders with more than 20 years of experience, if you need hydraulic cylinder design and cushioning components, please contact us at sales01@phtl.cn