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Trouble animating a rack and pinion system.

I'm a student trying to animate a rack and pinion system for a project. In most applications of a rack and pinion system, the pinion gear is fixed to and axle and its rotations move the rack forwards and backwards. In my design, though, the rack is fixed and the pinion gear (which is attached to a motor) moves back and forth.

My issue is that whenever I try to animate the relation, the software always ends up making the gear stationary and moving the rack - I need the opposite. I've tried fixing the rack in place and attaching it to other fixed components in the assembly, but nothing seems to be working.

Does anyone know how to fix this?


  • edward_petrilloedward_petrillo Member Posts: 45 EDU
    Your difficulty arises from the fact that the gear can't be a partner in both a revolute mate and a slider mate at the same time. 

    Your mechanism requires a linear guide to support the motor and gear as they move along the rack.  Let's presume that the motor is mounted to a frame that holds it in place.  Create a slider mate between the motor frame and the rack so that the frame moves along the rack.  Mate the gear to the motor shaft with a revolute mate, and then create a rack and pinion relation between the revolute mate and the slider.  Adjust the distance per revolution and the direction to get the desired result.  
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