WOLFRAM SYSTEM MODELER

SpoolWithAPreLoad

Model of a preloaded spool using ElastoGap components.

Diagram

Wolfram Language

In[1]:=
SystemModel["EducationExamples.MechanicalEngineering.SpoolWithAPreLoad"]
Out[1]:=

Information

To avoid chattering when using a spool in a hydraulic valve, it is often necessary to hold the spool in a locked position until the external force exceeds a certain threshold value. In this example of a spool with a preload, we will explore the interaction between such a force and the spool's position.

System Architecture

The system is a standard example in the Modelica.Mechanics.Translation library showing an example of usage of the ElastoGap component (the outer and inner contacts in the model). The ElastoGap component is essentially a spring-damper component with a gap, meaning that the spring damper will only be used if the gap is closed. This behavior simulates the desired preload to the spool.

A force is generated from a source and applied to the spool. When the spool has moved a threshold distance, which has the effect of loading a force in a spring, the gap is closed in the Contact components and the spool will begin to move.

Further Investigation

In the accompanying notebook, the behavior of this system is animated and can be interacted with.

In order to get the full experience of this example, you need a desktop Wolfram Language product. A free trial download is available at www.wolfram.com/mathematica/trial/

For the full example, open the accompanying notebook SpoolWithAPreLoad.nb.

Parameters (6)

forceAmplitude

Value: 150

Type: Force (N)

Description: Amplitude of input force

forceFrequency

Value: 0.01

Type: Frequency (Hz)

Description: Input force frequency

length

Value: 0.0115

Type: Length (m)

Description: Spool length

mass

Value: 0.15

Type: Mass (kg)

Description: Spool mass

housingLength

Value: 0.0305

Type: Length (m)

Description: Length of spool housing

housingDamping

Value: 2500.0

Type: TranslationalDampingConstant (N⋅s/m)

Description: Damping from friction for the spool sliding in the housing

Components (17)

innerContactA

Type: ElastoGap

Description: 1D translational spring damper combination with gap

innerContactB

Type: ElastoGap

Description: 1D translational spring damper combination with gap

spool

Type: Mass

Description: Sliding mass with inertia

fixedLe

Type: Fixed

Description: Fixed flange

springPlateA

Type: Mass

Description: Sliding mass with inertia

springPlateB

Type: Mass

Description: Sliding mass with inertia

spring

Type: Spring

Description: Linear 1D translational spring

outerContactA

Type: ElastoGap

Description: 1D translational spring damper combination with gap

outerContactB

Type: ElastoGap

Description: 1D translational spring damper combination with gap

rod1

Type: Rod

Description: Rod without inertia

friction

Type: Damper

Description: Linear 1D translational damper

force

Type: Force

Description: External force acting on a drive train element as input signal

housing

Type: Rod

Description: Rod without inertia

rod3

Type: Rod

Description: Rod without inertia

rod4

Type: Rod

Description: Rod without inertia

rod2

Type: Rod

Description: Rod without inertia

sineForce

Type: Sine

Description: Generate sine signal