Glossary · Pneumatics and hydraulics
End-position cushioning
Also known as: Cylinder cushioning, End-of-stroke cushioning
German: Endlagendämpfung
In fluid power, end-position cushioning is the deceleration of a cylinder's piston before it reaches the end of its stroke, achieved by elastic bumpers or by throttling the trapped air or oil through an adjustable or self-adjusting cushion.
- Fluid power
In one sentence
End-position cushioning slows a cylinder piston before end of stroke using bumpers or throttled trapped fluid, reducing impact.
Example
After a heavier gripper was installed, the technician readjusted the cylinder's pneumatic cushioning screws to stop the hard impact at the end position.
How it applies
- Engineering: The cushioning must absorb the kinetic energy of piston and load; manufacturers give permissible energy or mass-speed diagrams. External shock absorbers take over when the cylinder's cushioning isn't enough.
- Commissioning: Adjustable cushions are set with the real load; too little causes impacts, too much causes bouncing or slow end positioning.
- Maintenance: Worn cushions increase noise and wear on the cylinder and mechanics.
- Documentation: Describe adjustment in the maintenance instructions, including which screw does what and the check afterward. Note that changes in load or speed require readjustment.
Cushioning vs. speed control
Speed control with flow-control valves sets travel speed over the whole stroke. Cushioning only acts at the end of the stroke.