WOLFRAM SYSTEM MODELER

SpoolWithAPreLoad

Model of a preloaded spool using ElastoGap components.

Diagram

Wolfram Language

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

Information

 

Spool with a Preload

 

Introduction

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.

In order to get the full experience of this example, you need the following:

 

These pages show an overview of the example. For the full example, open the accompanying notebook SpoolWithAPreLoad.nb.

 

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.

DiagramImage570

Above is a diagram view of the model.

 

Further Investigation

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

CDFImage

 

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

innerContactB

Type: ElastoGap

spool

Type: Mass

fixedLe

Type: Fixed

springPlateA

Type: Mass

springPlateB

Type: Mass

spring

Type: Spring

outerContactA

Type: ElastoGap

outerContactB

Type: ElastoGap

rod1

Type: Rod

friction

Type: Damper

force

Type: Force

housing

Type: Rod

rod3

Type: Rod

rod4

Type: Rod

rod2

Type: Rod

sineForce

Type: Sine