Mechanism | Add Rack-Pinion - Ball-Screw

Rack and Pinion / Ball-Screw

See also Rack-Pinion dialog-box

A Rack is a Linear-Gear that engages with a Pinion, which is a Circular-Gear. The Rack-Pinion pair converts linear to angular motion, or rotary to linear motion. The linear motion of the Rack is directly related to the angular motion of the Pinion.

A Ball-Screw is a device that converts rotary motion of a screw to linear motion of a nut.

You can use the Rack-Pinion dialog-box to convert a Rack-Pinion to a Ball-Screw.

To add the Ball-Screw, you must first add the Rack-Pinion. Then use the Rack-Pinion dialog-box to change the Rack-Pinion to a Ball-Screw.

Preparation:

Add Rack-Pinion / Ball-Screw

Rack and Pinion

Driving-Pinion - Driven Rack

	PREPARATION: Driving-Pinion + Driven Rack. • Line in Part A, a Green Part, a rotating-Part, and will become the Driving-Pinion. • Line in Part B, a Blue Part-Outline, a sliding-Part, and will become the Driven Rack. Note: • The two Parts are joined to the same third Part. The third Part is the Base-Part. • It is not necessary that the Slide-Joint is axial with the Part that becomes the Rack. Add Rack-Pinion 1. Click Add menu > Mechanism sub-menu > Add Rack-Pinion / Ball-Screw - or - 1. Click Machine element toolbar > Add Rack-Pinion / Ball-Screw The Command-Manager now has two selection-boxes. You must select the two Line elements: 2. Click the CAD-Line in the Part with the Green Part-Outline, it is a kinematically-defined Part. 3. Click the CAD-Line in the Part with the Blue Part-Outline; it is NOT a kinematically-defined Part, 4. Click in the Command-Manager The Rack-Pinion is in the Assembly-Tree and Graphic-Area. Note: • The Pinion may be very small ! • The Rack is parallel to the CAD-Line in the Sliding-Part. It is offset by the Pitch-Circle Radius of the Pinion. • Use the Rack-Pinion dialog-box to edit the radius of the Pinion. • If you close the model and open it at a later time, you may need to use 'Rebuild' to regenerate the symbols for the Rack-Pinion.

Driving Rack - Driven-Pinion

	PREPARATION: Driving Rack + Driven-Pinion. • Line in a Green Part. In this case, a the CAD-Line in the Slider, which becomes the Driving-Rack. • Line in a Blue Part, a rotating-Part, which becomes the Driven-Pinion. Note: • The two Parts are joined to the same third Part. The third Part, in this example, is the Base-Part. • In this case, the Slide-Joint is axial with the Part that becomes the Rack. Add Rack-Pinion: command 1. Click Add menu > Mechanism sub-menu > Add Rack-Pinion / Ball-Screw - or - 1. Click Machine element toolbar > Add Rack-Pinion / Ball-Screw The Command-Manager now has two selection-boxes. You must select the two Line elements: 2. Click the CAD-Line in the Part with the Green Part-Outline. 3. Click the CAD-Line in the Part with the Blue Part-Outline. 4. Click in the Command-Manager. The Rack-Pinion is in the Assembly-Tree and Graphic-Area. Note: • The Rack is parallel to the CAD-Line in the Sliding-Part. It is offset by the Pitch-Circle Radius of the Pinion. • Use the Rack-Pinion dialog-box to edit the number of Gear-Teeth of the Pinion, the module of the Gears, and to move the Rack along the Pitch Line, if needed.