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

Add Gear-Pair

Terminology and definitions:

Gear-Pair :	Two gear wheels with gear-teeth that are in mesh. When one gear rotates the other gear must also rotate. The angular velocity of each gear is related to the number-of-teeth on each gear-wheel.
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.
External Mesh :	The gears have teeth that diverge out from their centers-of-rotation.
Internal Mesh :	One of the gears has teeth that converge to its center-of-rotation.
Simple Gear-Pair :	Two gears that rotate about fixed centers.
Epicyclic Gear-Pair :	One gear orbits around the center of the other gear.

Kinematic state before you do Add Gear-Pair

There are three Parts.

There is a Line in a Part that is kinematically-defined. The Line must have a dimension to define its length.

A Part is joined with a Pin-Joint to each end of the Line - two rotating-Parts.

One rotating-Part is kinematically-defined.

The other rotating-Part is not kinematically-defined before you do Add Gear-Pair. The three Parts have one degree-of-freedom.

Kinematic state after you do Add Gear-Pair

Add Gear-Pair removes the one degree-of-freedom from the three Parts.

The motion of Driven Part is found from the number-of-teeth , and mesh on each gear-wheel in the Gear-Pair.

Kinematics-Tree of Gear-Pair

Add Gear-Pair removes one degrees-of-freedom.

MD-ADD-GEARPAIR-KINEMATICS-TREE

Gear-Pair

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

After you do Add Gear-Pair, the rotating-Part that had one degree-of-freedom becomes a Geared Rocker and it is also kinematically-defined.

Preparation

Simple Gear-Pair

MD-ADD-GEARPAIR-0

Three(3) Parts, three(3) Lines, two(2) Pin-Joints ...

Line & Line are in Green Parts that are kinematically-defined

Line is in a Part that is not kinematically-defined

Lines are joined with Pin-Joints to each end of Line

Line has a dimension (in the Part-Editor)

Line is kinematically-defined after you do Add Gear-Pair.

Epicyclic Gear-Pairs

MD-ADD-GEARPAIR--EPI-0

Three(3) Parts, three(3) Lines, two(2) Pin-Joints ...

Line & Line are in Parts that are kinematically-defined

Line is in a Part that is not kinematically-defined.

Lines are joined with Pin-Joints to each end of Line

Line has a dimension (in the Part-Editor)

Line (and the Part) is kinematically-defined after you do Add Gear-Pair.

Add Simple Gear-Pair

MD-CM-AddGearPair-0

STEP 1: Click Add Gear-Pair (Simple)

1.Mechanism-Editor: Add menu > Mechanism menu > Add Gear-Pair

- or -

1.Mechanism-Editor: Machine-elements toolbar > Add Gear-Pair

There are four elements to select in the Command-Manager

MD-ADD-GEARPAIR-1

STEP 2: Select the four elements

1.Mechanism-Editor > Click Line

2.Mechanism-Editor > Click Line

3.Mechanism-Editors : Click Line

MD-ADD-GEARPAIR-2

STEP 2: continued...

The Part-Editor opens automatically.

4.Part-Editor: Click the Dimension

The Part-Editor closes automatically.

MD-CM-AddGearPair-full

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 Gear centers - called the Line-of-centers - becomes a Driven-Dimension. (The Length Dimension = (# Gear-Teeth 1 + # Gear-Teeth 2) * Module)

The output Part is a Geared-Rocker in the Kinematics-Tree.

To edit the Gear-Pair parameters: see Gear-Pair dialog-box

MD-ADD-GEARPAIR-3

Add Epicyclic Gear-Pair

MD-CM-AddGearPair-0

STEP 1: Click Add Gear-Pair (Epicyclic)

1.Mechanism-Editor: Add menu > Mechanism menu > Add Gear-Pair

- or -

1.Mechanism-Editor: Machine-elements toolbar > Add Gear-Pair

There are four elements to select in the Command-Manager

MD-ADD-GEARPAIR--EPI-1

STEP 2: Select the four elements

2.Mechanism-Editor > Click Line

3.Mechanism-Editor > Click Line

4.Mechanism-Editor > Click Line

MD-ADD-GEARPAIR--EPI-2

STEP 2: continued...

The Part-Editor opens automatically.

4.Part-Editor: Click the Dimension

The Part-Editor closes automatically.

MD-CM-AddGearPair-full

STEP 3: Complete the Command

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

MD-ADD-GEARPAIR--EPI-3

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. (Length = (# Gear-Teeth 1 + # Gear-Teeth 2) * Module)

The output Part is a Geared-Rocker in the Kinematics-Tree.

To edit the Gear-Pair parameters, see Gear-Pair dialog-box

Videos of Add Gear-Pair

Simple Gear-Pairs:

Epicyclic Gear-Pairs: