Getting Started Tutorials - MechDesigner > Tutorial 14: Gear-Pairs / Rack-Pinions > Before and After: Graphic-Area & Kinematic-Tree

Before and After: Graphic-Area and Kinematics-Tree

Summary

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

Preparation - Before Add Gear-Pair

Basic Preparation for Add Gear-Pair

Typical preparation for Add Gear-Pair

Three Parts:

•two Parts that are kinematically-defined

•one Part that is not kinematically-defined - it has one degree-of-freedom.

Three Lines *

•a Line in each Part

Two Pin-Joints:

•Pin-Joint to join the start-Point of Line to the start-Point of Line

•Pin-Joint to join the end-Point of Line to the start-Point of Line

One dimension for Line

•Use the Part-Editor to add a dimension to control the length of Line.

* Lines and CAD-Lines

We use the term Line-of-Centers for Line.

Result - After Add Gear-Pair

Immediately After Add Gear-Pair

After Add Gear-Pair

Part is now kinematically-defined. Part is the Geared-Rocker in the Kinematics-Tree.

The gear-parameters, together with the motion of Part, control the motion of Part

Use the Gear-Pair dialog to define the gear-parameters.

Pin-Joints are the rotational-centers of the gears.

Kinematics Trees: GEARED-ROCKER- before and after Add Gear-Pair

BEFORE
Add Gear-Pair

Before Add Gear-Pair

There are two kinematic-chains: a Kinematic-Chain and an Unsolved Mech

Rocker

•ANY rotating-Part that is kinematically-defined (for example, a Rocker)

Unsolved Mechs

•A rotating-Part that is NOT kinematically-defined

AFTER
Add Gear-Pair

After Add Gear-Pair

The Kinematic-Chain now has two Solved Kinematic-Chains:

Rocker

•Any rotating-Part that is kinematically-defined (for example, a Rocker)

Geared-Rocker

The Geared Rocker is kinematically-defined (solved).

The Geared Rocker includes these elements:

•Pin-Joint

•Part

•Gear-Pair

The motion of a Geared Rocker is a controlled by the motion of the Solved Part and the parameters that you edit in the Gear-Pair dialog.

Basic Gear-Pair Arrangements

Use Add Gear-Pair for these gear arrangements.

Gear-Pair: Fixed Gear Centers

Mesh: External		Mesh: Internal
Step Down: # Teeth Gear 1 < Gear 2	Step Up: # Teeth Gear 1 > Gear 2	Step Up: # Teeth Gear 1 > Gear2	Step Down: # Teeth Gear 1 < Gear2

Click to play each video

Gear-Pairs: Orbiting Gear Centers

Mesh: External		Mesh: Internal
# Teeth: Gear 1 < Gear 2	# Teeth: Gear 1 > Gear 2	# Teeth: Gear 1 > Gear2	# Teeth: Gear 1 < Gear2

Before and After: Graphic-Area & Kinematics-Tree