Spool Force
Component with two horizontal hydraulic connections
Description
Equations
Variables
Connections
Parameters
The Spool Force component models an axial hydraulic back-force exerted on the spool by the hydraulic fluid flowing through the valve.
This component must be connected in series with the spool valve in the circuit where the pressure-flow characteristic is based on the equations of the Orifice component.
Variation
The Variation parameter selects one of two options that determine how k, a coefficient for the spool force, is computed from a look-up table:
1. The table specifies the jet angle θ as a function of the displacement; k is the cosine of the jet angle.
2. The table specifies k directly as a function of displacement.
The Force Direction parameter specifies the direction of force applied to the spool.
{{θ=MapleSim.Interpolate1Ddataθ,displacement,2,Smoothnessk=cosθconvertedθconverted=π180θ}variation=1k=MapleSim.Interpolate1Ddatak,displacement,2,Smoothnessvariation=2
p=pA−pBq=qA=−qB
A=maxArea,Amin
F=ρq2AkorientFdir
Fdir={1Force Direction=1−1Force Direction=2
orient={10≤q−1otherwise
displacement={1000xdispUnit1=1xotherwise
Name
Units
Modelica ID
p
Pa
Pressure drop from A to B
q
m3s
Flow rate into port A
displacement
mm
Valve displacement
θ
degree
Jet angle in degrees
theta
θconverted
radian
Jet angle in radians
theta_converted
portA
Hydraulic port on left side
portB
Hydraulic port on right side
Area
Signal input; orifice cross-section in mm2
x
Signal input; valve displacement in m
Data Parameters
Default
1
Data source variation
paramType
Data source
inline
Data source for jet angle as a function of displacement
datasourcemode1
θx
First column: displacement, second column: jet angle
table_theta
dataθ
data_theta
Force direction
Direction of spool force
paramType2
Data source for k as a function of displacement
datasourcemode2
kx
First column: displacement, second column: discharge coefficient
table_k
datak
data_k
Smoothness
linear
Smoothness of table interpolation for all the data
θunit
Unit of jet angle used in the data table
dispUnit1
Displacement unit
Unit of displacement used in the data table
dispUnit2
Fluid Parameters
The following parameters, used in the equations, are properties of the Hydraulic System Properties component used in the model.
ν
m2s
Kinematic viscosity of fluid
nu
ρ
kgm3
Density of fluid
rho
El
Bulk modulus of fluid
See Also
Hydraulics Library
Valve Forces
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