================
Rack and pinion 
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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

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

   .. image:: media/lp_rack_and_pinion.png
      :alt: Rack and pinion link definition
      :scale: 100 %


^^^^^^^^^^^^^^^^^^^^
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
==============  ===========================================================================================

^^^^^^^^^^^^^^^^^^^^^^^^^
Recommended link settings
^^^^^^^^^^^^^^^^^^^^^^^^^

==========================  ==========================
Use ground for source       unchecked
Location master             none
Orientation master          either source or target
==========================  ==========================

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Parameters
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===================  =========  =======================================================================
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 damping      Ns/m       Damping of the contact between the teeth
===================  =========  =======================================================================