CylinderSpringReturn

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CylinderSpringReturn

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Iconic Diagrams\Hydraulics\Cylinders\Basic Cylinders

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Hydraulics/Translational).

Description

CylinderSpringReturn

This is an ideal model of a single acting cylinder with no mass and no friction and a return spring to drive the cylinder back when there is no pressure in the chamber. The volume of the chamber is given by:

 

V = Vdead + Aa*(x + x_initial)

 

with Aa the piston area, x the piston position and Vdead the initial volume when piston position is zero. The piston area Aa is related to the piston diameter dp by:

 

Aa = pi * dp^2 / 4

PistonDiameter

The driving force of the return spring is determined by two parameters: the force for piston position zero (Fspr_min) and the force when the piston is at the other side (Fspr_max). The spring constant (kspr) and initial spring position (x0) are calculated out of these parameters by:

 

kspr = (Fspr_max - Fspr_min)/stroke

x0 = -Fspr_min/kspr

 

There is no restriction on the travel of the piston. Only a warning is given when the maximum stroke is exceeded or the piston position gets negative.

Interface

Ports

Description

pa

pm

hydraulic port

translation port

Causality

 

preferred pressure out pa

preferred force out pm

 

Parameters

 

Vdead

B

stroke

x_initial

dp

Fspr_min

Fspr_max

rest volume of oil in cylinder chamber when closed [N.s/m]

effective bulk modulus [Pa]

stroke length [m]

starting position of piston [m]

piston diameter [m]

minimum return spring force (at x = 0) [N]

maximum return spring force (at x = stroke) [N]