Gearing FB

Summary of Gearing FB

The default motion-values at the output of the Gearing FB are equal to its input motion-values.

You can edit three parameters in the Gearing FB dialog-box to edit its output. The three parameters apply to a linear equation:

Output = (a × (input + b) + c)

The 'Gearing Ratio Parameter, a, can be entered as a rational number [a ratio of two numbers to give, e.g.: 355/113] or as an irrational number [e.g.: pi].

Add and Edit Gearing FB



Kinematics FB toolbar > Gearing FB [right of Graphic-Area]


Add menu > Add Gearing FB


STEP 1: Add the Gearing FB to the graphic-area

1.Single-Click the Kinematics FB Toolbar > Add Gearing FB
2.Single-Click again in the graphic-area to 'place' the Graph FB in the graphic-area.

The Gearing FB is now in the graphic-area.


STEP 2: Open the Gearing FB dialog-box:

1.Double-click the Gearing FB in the graphic-area.

- or -

The Gearing FB dialog-box

Default output:

The default output from the Gearing FB is equal to its input.

Output Function:

It has three parameters, which specify a simple linear equation function.

The equation of the Gearing FB is:

Output = {1r×(Input +3r)}+ 2r

Gearing FB dialog-box

Gearing FB dialog-box

Ratio and Phase

1s-red Gearing Ratio

Multiply the result of (Input+ 3s) by this parameter Gearing-Ratio

[See Irrational and Ratio Ratio radio buttons below].

2s Add after Gear Ratio

Add this parameter to the result of [1s-red × (Input+3s )]

3s Add before Gear Ratio

Add this parameter directly to the input : (Input+3s)

Rational Gear

4s You can enter Gearing Ratio in two different ways.

Click ...

Gearing as 'Real' [Irrational] radio-button ... to enter any number (Irrational and Rational) in the Gearing Ratio box1s-red

- or -

Gearing as 'Ratio' [Rational] radio button ... to enter two integers [±] in the Input-Pulley5s and Output-Pulley6s boxes

The ratio of Input-Pulley / Output-Pulley shows in the Gearing Ratio as a 'Read-Only' parameter.

Notes: Gearing Ratio [ignoring the other two parameters]

-1 < Gearing Ratio < 1 ; the output is 'stepped down' [becomes less than the input]

Gearing Ratio < 0 ; the output is opposite to [negative of] the input.

Gearing Ratio = 1 ; the output is equal to the input

Gearing Ratio =-1 ; the output is equal, but the opposite to [negative of] the input


Use a Gearing Ratio = '-1' to reverse the direction of a Crank.
Connect a Gearing FB to the input of a Motion FB to change the number of times you complete a Motion in one Machine Cycle - Motion Frequency
Connect the output of a Motion FB to the input of a Gearing FB to change the amplitude of the motion - Motion Amplitude/Range.

See Also:

Connecting FBs

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd