﻿ MechDesigner Reference & User Interface > 2.2 Mechanism-Editor: > Machine elements > Add Gear-Pair

Add Gear-Pair removes one(1) degree-of-freedom from a rotating-Part.

#### Terminology and definitions:

 Gear-Wheel : A rotating-Part with gear-teeth at a fixed diameter. The diameter is defined by the number and the module of the gear-teeth. Gear-Pair : Two inter-locking gear-wheels. Their teeth are in mesh. The angular velocity of each gear-wheel is related by the number-of-teeth on each gear-wheel, and the type of mesh. Driving Part : The rotating-Part that is kinematically-defined, and whose motion is defined (even if it is stationary) before you do Add Gear-Pair Driven Part : The rotating-Part whose motion is defined after you do Add Gear-Pair by the Driven-Part, the Number-of-Teeth on each Gear in the Gear-Pair, and the Mesh. Gear-Mesh : Inter-locking gear-teeth of a Gear-Pair that allow a torque and motion to be transmitted from one shaft to a different shaft. External Mesh : The two gear-wheels have gear-teeth that point outwards from their centers-of-rotation. Internal Mesh : One of the gear-wheels has gear-teeth that point inwards towards its center-of-rotation. Simple Gear-Pair : Two gear-wheels that rotate about two fixed centers. Epicyclic Gear-Pair : One gear-wheel orbits around the center of the other gear-wheel.

### Prepare to do Add Gear-Pair

#### Simple Gear-Pair

3 × Parts ; 3 × Lines ; 2 × Pin-Joints

 Line & Line and Parts are kinematically-defined Line and Part is not kinematically-defined Lines are joined with Pin-Joints to each end of Line Line has a dimension (in the Part-Editor)

#### Epicyclic Gear-Pairs

3 × Parts ; 3 × Lines ; 2 × Pin-Joints

 Line & Line and Parts are kinematically-defined Line and Part is not kinematically-defined. Lines are joined with Pin-Joints to each end of Line Line has a dimension (in the Part-Editor)

#### Simple Gear-Pair

STEP 1: Click Add Gear-Pair (Simple)

There are four elements to select in the Command-Manager

STEP 2: Select the four elements

 1.Mechanism-Editor > Click Line 2.Mechanism-Editor > Click Line 3.Mechanism-Editors : Click Line

STEP 2: continued...

The Part-Editor opens automatically.

 4.Part-Editor:  Click the Dimension

The Part-Editor closes automatically.

STEP 3: Complete the Command

 5.Command-Manager: Click in the Command-Manager.

Result:

 The Gear-Pair is in the graphic-area. The default Gear-Pair has an External Mesh and they have same number-of-teeth. The length of the Line between the centers of the gears - called the Line-of-centers - becomes a Driven-Dimension. The length of the Line-of-Centers = (# Gear-Teeth 1 + # Gear-Teeth 2) × Module The output Part is a Geared-Rocker in the

To edit the Gear-Pair parameters:

#### Epicyclic Gear-Pair

STEP 1: Click Add Gear-Pair (Epicyclic)

There are four elements to select in the Command-Manager

STEP 2: Select the four elements

 2.Mechanism-Editor > Click Line 3.Mechanism-Editor > Click Line 4.Mechanism-Editor > Click Line

STEP 2: continued...

The Part-Editor opens automatically.

 4.Part-Editor:  Click the Dimension

The Part-Editor closes automatically.

STEP 3: Complete the Command

 5.Command-Manager: Click in the Command-Manager.

Result:

 The Gear-Pair is in the graphic-area. The default Gear-Pair has an External Mesh and the gears have same number-of-teeth. The length of the Line between the Gear centers - called the Line-of-centers - becomes a Driven-Dimension. The length of the Line-of-Centers = (# Gear-Teeth 1 + # Gear-Teeth 2) × Module) The output Part is a Geared-Rocker in the

To edit the Gear-Pair parameters,

### Kinematics-Tree of Gear-Pair

Gear-Pair

 Before you do Add Gear-Pair: •a rotating-Part that is kinematically-defined •a rotating-Part that is NOT kinematically-defined - it has one degree-of-freedom. After you do Add Gear-Pair, •the two rotating-Part are kinematically-defined •the rotating-Part that had one degree-of-freedom is now a Geared Rocker