Mechanism Design and Mechanism Dynamics > Mechanism Design > Creating Mechanism Models > Modeling Entities > Gears > About Measures for Generic and Dynamic Gears
  
About Measures for Generic and Dynamic Gears
A gear defines a reduction ratio between two selected axes. You can measure various quantities on a gear connection, although most quantities can be used only with dynamic gears. The meaning of each quantity can also be affected by the type of axis it measures.
Reaction Measure
Gear Type
Description
Axial moment
All circular gears
The torque exerted on the appropriate rotational axis of the body. This is a signed quantity, with positive direction coincident with the positive direction of the axis.
Dynamic racks only
The moment generated by the resultant of normal and lateral force. This is a signed quantity with positive direction coincident with the positive direction of the axis.
Axial force
Dynamic circular gears only
The force exerted along the axis. The axial force is applied at the pitch point. It is present in bevel gears or as a result of a helical angle. This is a signed quantity with positive direction coincident with the positive direction of the axis.
All racks
The force exerted on the appropriate translational axis of the body. This is a signed quantity with positive direction coincident with the positive direction of the axis.
Radial force
Dynamic circular gears only
The force exerted along the radius of the pitch circle. The radial force is applied at the pitch point as a result of a pressure angle. This is a signed quantity with positive direction defined from the pitch point towards the center of the pitch circle. The direction of the radial and the axial forces is always perpendicular.
Tangential force
Dynamic circular gears only
The force exerted along the tangent to the pitch circle. The tangential force is applied at the pitch point. The axial moment exerted on the same body is a result of this force. This is a signed quantity. When its positive direction is used as X with the positive radial direction as Y and the positive axial direction as Z, it defines a right-hand coordinate system.
Lateral force
Dynamic racks only
The force exerted on the rack pitch plane which is perpendicular to the axial force. The lateral force is collinear with the pinion tangential force. This is a signed quantity. When its positive direction is used as X with the positive normal direction as Y, and the positive axial direction as Z, it defines a right-hand coordinate system.
Lateral moment
Dynamic circular gears only
The moment generated by the axial force. The lateral moment is applied to the center of the pitch circle. This is a signed quantity, and its direction is coincident with the direction of the tangential force.
Dynamic racks only
The moment generated by the axial force. The lateral moment is applied to the point on the translation axis nearest the pitch point. This is a signed quantity. When its positive direction is used as X with the radial direction towards the pitch point as Y, and the positive axial direction as Z, it defines a right-hand coordinate system.
Total force
Dynamic circular gears and racks
The sum of all force components. This is an unsigned quantity that defines force magnitude.
Total moment
Dynamic circular gears and racks
The sum of all moment components. This is an unsigned quantity that defines moment magnitude.
Normal force
Dynamic racks only
The force perpendicular to the rack pitch plane. The normal force is applied at the pitch point and it is antiparallel to the pinion radial force. This is a signed quantity with positive direction that is opposite to the pinion radial force.
 
These joint reaction measures are automatically calculated and superimposed on the standard joint reaction measures.
If the gear type is changed, unusable measures remain in the Measures list but are labeled Not Computed.
When you play back an analysis, you can display the reaction force measures as vectors on the pitch point. The reaction moment measure vectors are displayed on the axes, at the centers of the respective pitch circles.