Belt drive

Belt drive link properties implement a toothed belt drive. Only the linear elastic behaviour is modelled, non-linearities are neglected. The simplifications are:

  • the belt is always considered prestressed (both strands are contributing to the stiffness)

  • the prestress force 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 pulleys is not modelled

Definition

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

Belt drive link definition

Source interface

Type

Stationary interface (6dof)

Topologies

Peripheral face of the source pulley

Location

Center of the source pulley

u direction

Axial, along the axis of rotation of the source pulley

v direction

Pointing towards the center of the target pulley

w direction

Resulting direction

Target interface

Type

Stationary interface (6dof)

Topologies

Peripheral face of the target pulley

Location

Center of the target pulley

u direction

Axial, along the axis of rotation of the target pulley

v direction

Aligned with the v-direction of the source interface

w direction

Parallel to the w-direction of the source interface

Parameters

Parameter

Unit

Symbol

Description

Source gear radius

m

\(r_S\)

Radius of the pitch line of the source pulley

Target gear radius

m

\(r_T\)

Radius of the pitch line of the target pulley

Belt stiffness

N/m

\(k\)

Stiffness of one strand of the belt including tooth compliance

Belt damping

Ns/m

\(d\)

Damping coefficient of one strand of the belt

The stiffness of the belt can be calculated using the specific stiffness \(c_{st}\), the width of the belt \(b\), and the free lenght of a strand \(l_{1}\) according to \(k = c_{st} \, b / l_1\).