Rack and pinion

Rack and pinion link properties implement a rack and pinion drive. Only the linear elastic behaviour is modelled, non-linearities are neglected. The simplifications are:

  • any kind of backlash is neglected

  • the force pushing the pinion and rack apart (due to the pressure angle of the teeth) is not modelled and has to be added as load in an analysis if desired

  • irregular transmission due to the teeth is not modelled

  • local deformation of the pinion is not modelled

Definition

Source and target interfaces should be chosen as shown in following figure:

Source interface

Type

Moving interface (Fourier)

Topologies

Side faces of the rack

Location

Along the pitch line

u direction

Axial, along the pitch line

v direction

Transversal

w direction

Normal, towards the pinion

Target interface

Type

Stationary interface (6dof)

Topologies

Peripheral face of the pinion

Location

Center of pinion

u direction

Axial, along the pitch line of the rack

v direction

Parallel to the v-direction of the source interface

w direction

Parallel to the w-direction of the source interface

Parameters

Parameter

Unit

Description

Pinion radius

m

Radius of the pitch line of the pinion

Contact stiffness

N/m

Stiffness of the contact between the teeth

Contact viscous damping

Ns/m

Viscous damping of the contact between the teeth

Contact hysteretic damping

None

Hysteretic damping of the contact between the teeth