Planetary gear system in Solidworks

Planetary gear drives have revolutionized the automotive industry. They are used in automatic transmissions to shift between gears.

The gear drive is connected to the engine output shaft via a torque converter which replaced the traditional clutch used in manual transmissions. Below is a simple demonstration on how to insert the gears making up the system (Sun, planet and ring gear) in an assembly and subsequently running a motion study to see how the gears move relative to each other.

First, we begin by creating a new assembly.


From the assembly create a sketch representing the dimensions of the gears to be inserted. Constrain circles tangent to each other by defining a tangent relationship between them.

Your final sketch should look like the one below.



Exit the sketch then use the axis tool to define axes at the centers of the circular sketches.




To insert the gears on the assembly you need to first enable the Solidworks Toolbox add-in in the add-ins folder.

Move to the design library and add the toolbox. You can then proceed to the Metric tab and select power transmission. Here you find different gear sets like the ones shown below.


To add the gears into the window just simply right click and drag them to the window. Property Manager is then opened up and changes to the gear properties, aspects like the module, face width and the number of teeth can be made. The specifications below shows the properties of the sun gear.


Go ahead and set up the constraints, with the back face of the gear being coincident with the front plane and the hub being concentric with the axis of the central circular sketch.
Next, drag the another spur gear onto the window and define its properties as planet gears, then create copies for the other planet gears. Once you set up the constraints for these gears, the final setup should look like the one below.


Define gear mate relationships between the gears, then proceed to create a motion simulation study. Remember in order to do this you must first enable the SolidWorks motion simulation add-in.


In the motion study, you are only required to define the motor (driver) and its speed of rotation in rpm.

You can then run the animation and observe how the gears move relative to each other.

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