Step 14.3: Compound Gear-Trains

A Compound Gear Train has a minimum of:

In MechDesigner, it is easier to add Compound Gear-Trains than Simple Gear-Trains.

The image to the left shows a Compound Gear Train. There are three Gear-Pairs, two shafts have two gears.

Therefore, it agrees the definition of the Compound Gear Train.

See Also: Simple Gear-Pair, Simple Gear-Trains, Planetary Gear-Trains

We will use the model we have done in the previous Step LAdd a Gear-Pair with Fixed-Centres

Edit the number-of-teeth as follows.

Here, the number-of-teeth are:

Z1=20, Z2=40.

The Gear Ratio is Z1/Z2 = 2

Remember this basic rule::

Three Parts, three Lines, joined together with Pin-Joints. Two Lines must be in Parts that are kinematically-defined.

Preparation

To add a Compound Gear-Train, we use the same basic rule, again,and again.

We need three Parts each with a Line, A Line is joined with a Pin-Joint to each end of one Line.

Gear-Pair 2:

Before we start, we have a Line in a kinematically-defined Part.

Line 1 / Part 1 : Line is the CAD-Line in the Driven-Gear of Gear-Pair 1.

We need two more Parts and Lines.

Line 2 / Part 2 : It is a new Line in the Base-Part. It will be the Line that joins the gear-centres

2.	Part-Editor: Geometry toolbar > Add Line AND Add Dimension  (the actual length is not important).

IMPORTANT rule: You must MERGE Point and Point

You can Hover + Drag to add Line  from Point OR

3.	Part-Editor: Geometry toolbar > Merge-Points : Click Point and then click Point

Line 3 and Part 3 : It is a new Part - it will be the Driven-Gear.

1.	Mechanism-Editor: Kinematics-toolbar > Add Part: Drag to the Part

2.	Mechanism-Editor : Kinematics-toolbar > Add Pin-Joint  Join the start-Point of CAD-Line in Part to the end of Line, with a Pin-Joint.

The length the CAD-Line along Part is not important.

We are ready to Add Gear-Pair

Add Gear-Pair 2

Add Gear-Pair 2

2.	Click the elements, from top to bottom - refer to Preparation images, above

3.	Click  at the bottom of the Command-Manager.

You can see the Gear-Pair 2

MechDesigner adds two new gears.

This is a Compound Gear-Train.

You can do the same actions to add more Gear-Pairs.

This image shows Compound Gear-Train with three Gear-Pairs.

To make the Gears Solid