variabledisplacementmotor-leakage

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variabledisplacementmotor-leakage

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Iconic Diagrams\Hydraulics\Pumps

Use

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

VariableDisplacementMotor-Leakage

Description

This model describes an motor with internal and external leakage and an axial speed that is proportional to input flow rate:

 

pa.phi = pb.phi = i * p_rot.omega;

i = D / (2*pi);

 

The actual flows at the inlet and outlet port may be slightly different because of the flow into the lumped volumes and the leakage flows. The leakage flows are modeled by laminar resistances. The torque is equal to:

 

p.T = i*(pa.p - pb.p);

 

The displacement is controllable by the input signal c. For a positive rotation of the driving axis the flow is:

 

c >= 1

c = 0

c <= -1

maximum flow from port 1 to port 2

zero flow

maximum flow from port 2 to port 1

 

If the port pressure is smaller than the vapour pressure (p < p_vapour), the flow is zero. If the port pressure is larger than the vapour pressure the flow gradually grows to its normal value, until the atmospheric pressure (p = 0) is reached.

Interface

Ports

Description

pa

pb

p_rot

inlet port (hydraulic)

outlet port (hydraulic)

axis (rotation)

Causality

 

preferred pressure out pa

preferred pressure out pa

preferred angular velocity out p_rot

 

Input

 

c

relative displacement

Parameters

 

ExternalLeakage1\p_preload

ExternalLeakage1\G

ExternalLeakage2\p_preload

ExternalLeakage2\G

InternalLeakage\G

Va\V

Va\B

Va\p_initial

Vb\V

Vb\B

Vb\p_initial

Motor\D

Friction\d

Inertia\J

Tank pressure [Pa]

Conductance of laminar resistance [m3/s.Pa]

Tank pressure [Pa]

Conductance of laminar resistance [m3/s.Pa]

Conductance of laminar resistance [m3/s.Pa]

Volume of oil under pressure [m3]

Effective bulk modulus [Pa]

The starting pressure of the volume [Pa]

Volume of oil under pressure [m3]

Effective bulk modulus [Pa]

The starting pressure of the volume [Pa]

Displacement per revolution [m3]

Damping [N.m.s/rad]

Moment of inertia [kg.m2]