9 - AHP Merkle GmbH

1.10 Cushioning of the stroke
Tip
Internal and external cushioning is advisable for high travel speeds with a fast approach to the end position –
i.e. for also very dynamic drives. In this manner it is possible to prevent damage to the cylinder or to the piston
rod, to reduce operating noises, and to reduce wear in the application.
End of stroke cushioning has an additional benefi t in that they protect the hydraulic cylinders from running into
the end positions without a loss of force. The cushioning of the stroke is also advisable, for example, when
fi rst programming a system, or during commissioning. The stroke should be cushioned where the piston moves
against the stop with a speed greater than 0.1 m/s (0.328 feet/s)
The cushioning of the stroke in the hydraulic cylinders serves to absorb energy. At the end of the piston there
is a so-called dampening piston (image 1). This moves in a dampening bushing, thus separating the piston
chamber from the connection (image 2). The hydraulic fl uid then fl ows through channels to the return fl ow
connection (image 3). The cushioning characteristic curve is based on their dimensioning.
The cushioning of the stroke has an adjusting screw that can be used to vary the fl ow cross-section. This means
that the farther the piston moves in, the higher the cushioning effect. At a certain point the cushioning intensity
becomes constant to the end of stroke.
An optimal solution for reducing the piston speed at the end of stroke without loss
of force, is by cushioning the stroke of the AHP Merkle cylinder.
1
2
3
Basic information about hydraulic cylinders en
Dampening bushing
Dampening piston
Flow direction
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