Friction motor

The friction motor , actually a flywheel motor, is preferably used in toys such as cars, trains and the like. The word "friction" comes from Latin and means friction. The origin of the name is unclear, as no frictional forces contribute to the function.

Friction motor

A friction motor essentially consists of a flywheel and a reduction gear . The flywheel can be set in motion using the toy wheels or an additional rubber wheel in the middle . The toy is pressed against a surface and the flywheel is set in motion . If you let go of the toy, it will continue to move, driven by the momentum of the flywheel, until the rotational energy of the flywheel is used up. The reduction is necessary to set the flywheel in rapid rotation and because the energy of the flywheel is relatively small and so many rotations of the flywheel are required to turn the wheels of the toy. The bigger and heavier the flywheel, the harder the toy is to push, but the further it can travel at the same initial speed.

The flywheel is firmly connected to the wheel via the gearbox. There is no clutch and usually no freewheel .

The effective mass is increased by the flywheel. When accelerating, the vehicle pushes as hard as 20 vehicles and rolls on accordingly.

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The increase in mass refers to the moment of inertia of the flywheel, the gear ratio and the tire radius. ${\ displaystyle m}$ ${\ displaystyle J}$ ${\ displaystyle i}$ ${\ displaystyle r}$

This motor must not be confused with a drive device with an associated elevator (spring mechanism) that is driven by a tensioned spring. The friction motor saves part of the work of pushing the toy. The bicycles - or a special friction wheel with grippy rubber in the middle - drive the flywheel via a transmission, which drives the drive wheels of the toy via (partially) the same gear when it is released.

Friction motors are robust, simple and inexpensive to manufacture. Therefore, they are widely used in toys.