Add Rack-Pinion - Ball-Screw

<< Click to Display Table of Contents >>

Navigation:  MechDesigner Reference & User Interface > 2.2 Mechanism-Editor: > Machine elements >

Add Rack-Pinion - Ball-Screw

Add Rack and Pinion / Ball-Screw

See also Rack-Pinion dialog-box

Terminology

Rack -Pinion :

A Rack-Pinion is the term for a sliding, linear-gear (Rack) that is in mesh with a rotating, circular-gear (Pinion).

The motion of the two Parts are kinematically-related by the module and number-of-teeth on the Pinion.

Ball-Screw :

A Ball-Screw is a device in which a Screw rotates to move a Nut, or vice-versa. The Linear-Motion of the Nut and the rotation of the Screw are related by the lead of the screw-thread.  
tog_minusFurther Reading

Kinematic State before you do Add Rack-Pinion.

There are three Parts - 1,2,3.

Part(1) is joined to Part(2) with a Pin-Joint.

Part(3) is joined to Part(2) with a Slide-Joint.

Part(2) is kinematically defined

Either Part(1) OR Part(3) is kinematically-defined before you do Add Rack-Pinion.

Kinematic State after you do Add Rack-Pinion.

Add Rack-Pinion removes one degrees-of-freedom.

Part(1) and Part(3) are kinematically-defined after you do Add Rack-Pinion

Kinematics-Tree

MD-ADD-RACKPINION-KINEMATICS-TREE

Red-14-1 When the movement of the Pinion will come from the Rack

Before you do Add Rack-Pinion, there is a sliding-Part that is kinematically-defined and a rotating-Part that has one degree-of-freedom.

After you do Add Rack-Pinion, the sliding-Part(Rack) and the rotating-Part (Pinion) are kinematically-defined

Red-14-2 When the movement of the Rack comes from the Pinion

Before you do Add Rack-Pinion, the rotating-Part is kinematically-defined and the sliding-Part has one degree-of-freedom.

After you do Add Rack-Pinion, the rotating-Part (Pinion) and sliding-Part (Rack) are kinematically-defined, and in one kinematic-chain.

Preparation (typical)

When the movement of the Rack will come from the Pinion (Driving Pinion)

MD-GA-RackPinion-Prep-0

Elements before you do Add Rack-Pinion

LineRed-14-1 - in a rotating-Part that is kinematically-defined

LineRed-14-2 - in a Sliding-Part that is not kinematically-defined

 

When the movement of the Pinion will come from the Rack (Driving Rack)

MD-DRIVINGRACK-PINION-0

Elements before you do Add Rack-Pinion

LineRed-14-1 - in a Sliding-Part that is kinematically-defined

LineRed-14-2 - in a Rotating-Part that is not kinematically-defined

 

Add Rack and Pinion

When the movement of the Rack comes from the Pinion (Driving Pinion)

MD-CM-AddRackPinion-00

STEP 1: Click Add Rack-Pinion

Add Rack-Pinion Ball-Screw icon

1.Add menu > Mechanism menu  > Add Rack-Pinion

- or -

1.Machine-elements toolbar > Add Rack-Pinion

In the Command-Manager, there are two elements to select.

STEP 2: Select the two elements in the graphic-area

1.Click LineRed-14-1 - it is in the Part that is kinematically-defined.

2.Click LineRed-14-2 - it is in the Part that is NOT kinematically-defined.

STEP 3: Complete the Command

1.Command-Manager: Click OK-tiny-11-15 to complete Add Rack-Pinion.

Result :

The Pinion is on the Rotating-Part.

The rotating-axis of the Pinion is coincident with the Pin-Joint.

The Rack is on the Sliding-Part.

The Rack is parallel with the Slide-Joint.

The Pitch-Line of the Rack is offset from the center of the Pinion by the Pitch-Circle Radius of the Pinion.

The Sliding-Part is now a Part that is kinematically-defined.
MD-GA-RackPinion-Prep-0
MD-CM-AddRackPinion-01

When the movement of the Pinion comes from the Rack (Driving-Rack)

MD-CM-AddRackPinion-00

STEP 1:Add Rack-Pinion

Add Rack-Pinion Ball-Screw icon

1.Add menu > Mechanism menu  > Add Rack-Pinion

- or -

1.Machine-elements toolbar > Add Rack-Pinion

In the Command-Manager, there are two elements to select.

STEP 2:Select the two elements in the graphic-area

2.Click LineRed-14-1 - it is in the Part that is kinematically-defined.

3.Click LineRed-14-2 - it is in the Part that is NOT kinematically-defined.

STEP 3:Complete the Command

4.Command-Manager: Click OK-tiny-11-15 in the Command-Manager.

The Rack-Pinion is now in the Assembly-Tree and Graphic-Area.

Result :

The Pinion is on the Rotating-Part.

The rotating-axis of the Pinion is coincident with the Pin-Joint.

The Rack is on the Sliding-Part.

The Pitch-Line of the Rack is parallel to the Slide-Joint and Sliding-Part.

The Rotating-Part is now a Part that is kinematically-defined.
MD-DRIVINGRACK-PINION-0
MD-DRIVINGRACK-PINION-1

Video of Add Rack-Pinion

 

Video: Add Rack-Pinion