bigtrak Gearbox

The gearbox, also known as the transmission, consists of this black portion forming the underbelly of the toy. It consists of cogwheels forming a gear train. The transmission is responsible for converting the torque that the motor produces, into a usable force, which turns the wheels.

For the Milton Bradley version, the manufacturing origin of the gearbox assembly was at Superdex in Kowloon. Inspections were at the East Longmeadow machine shop in MA, near the Milton-Bradley plant on Shaker road. The inspection was for speed, torque, and current consumption, before final installation into the product.

I have removed the circuit board from the transmission. As you can see, the phototransistor encoder would fit into the window.

Dissecting the transmission, we can see a three-stage gear assembly driven by a pair of DC motors. The axle drive shaft appears to be made of steel with a plastic slip differential at each end.

Here is a plan view showing the gearbox transmission.

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