Load Case Rack and Pinion Drive

Tooth > Tooth pitch

The distance between two teeth on the rack.

The tooth pitch together with the number of teeth on the pinion determines the transmission ratio between the linear movement of the load and the rotary movement of the input shaft.

Tooth > Number of teeth on the pinion

The number of teeth on the pinion which drive the rack.

Diameter > Pinion diameter

The diameter of the pitch circle.

Mass of the load

Mass of the moved load (without the mass of the rack).

Mass of the rack

Mass of the rack.

Moment of inertia of the pinion

Moment of inertia of the pinion (without the inertia of the load and the rack).

Kinetic Friction force

A torque that applies to the input shaft.

This parameter can have a positive value, or 0.

During movement (when velocity is different from 0) this torque acts opposed to the direction of the motion. The absolute value of the torque during movement is constant, independent of the velocity.

At stand-still (velocity =0), this torque does not occur.

A typical example for this type of torque is kinetic friction between solid bodies.

Additional constant force

Static additional force at the input shaft.

A positive value or negative value, or 0, is allowed. A positive value indicates that the force applies in positive direction of the load. A negative value indicates that the force applies in negative direction of the load.

The absolute value and the direction of the force are constant and apply during motion and standstill. They are independent of the velocity.

An additional constant force is caused, for example, by a suspended load.

Viscous friction force

Velocity-dependent additional force at the input shaft.

This parameter can have a positive value, or 0.

The absolute value of the force is proportional to the absolute value of the velocity. The direction of the force is opposed to the direction of motion.

A viscous friction force is caused by the friction of a fluid.

Inclination angle

Inclination angle of the rack in degrees (–90°...+90°).

With a positive value, the rack is inclined in upward direction, meaning in opposite direction to the force of gravity. This increases the force required to move the load.

With a negative value, the rack is inclined in downward direction. This reduces the force required to move to load.

Selected motion profile

The motion profile that is used a a basis for calculations for this axis.

The motion profile of the load case Rack and pinion drive describes a linear movement of the load (legend item 6 in the graphic above the table).

Selected load profile

The load profile that is used in combination with another motion diagram to define an additional load. It allows you to define a load that is exerted on a servo axis during specific sequences of motion.