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Detailed Introduction on Gear Motor

By Susi | Published on Dec 10,2015

Working Principle

ears are used in tons of mechanical devices. They do several important jobs, but most important, they provide agear reduction in motorized equipment. This is key because, often, a small motor spinning very fast can provide enough power for a device, but not enough torque. For instance, an electric screwdriver has a very large gear reduction because it needs lots of torque to turn screws, bu­t the motor only produces a small amount of torque at a high speed. With a gear reduction, the output speed can be reduced while the torque is increased.

Another thing gears do is adjust the direction of rotation. For instance, in the differential between the rear wheels of your car, the power is transmitted by a shaft that runs down the center of the car, and the differential has to turn that power 90 degrees to apply it to the wheels.

There are a lot of intricacies in the different types of gears. In this article, we'll learn exactly how the teeth on gears work, and we'll talk about the different type­s of gears you find in all sorts of mechanical gadgets.­


A gear or cogwheel is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part to transmit torque, in most cases with teeth on the one gear being of identical shape, and often also with that shape on the other gear.[1] Two or more gears working in a sequence (train) are called a gear train or, in many cases, atransmission; such gear arrangements can produce a mechanical advantagethrough a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source. The most common situation is for a gear to mesh with another gear; however, a gear can also mesh with a non-rotating toothed part, called a rack, thereby producing translation instead of rotation.

The gears in a transmission are analogous to the wheels in a crossed belt pulley system. An advantage of gears is that the teeth of a gear prevent slippage.

When two gears mesh, and one gear is bigger than the other (even though the size of the teeth must match), a mechanical advantage is produced, with the rotational speeds and the torques of the two gears differing in an inverse relationship.


Gearmotors are electric motors that utilize a type of gear system on the output of the motor. This gearing arrangement is called a gear reducer or gearbox. The combination of an electric motor and gearbox reduces design complexity and lowers cost, particularly for motors built for high torque and low speed applications. In addition, gearboxes can be used as a means to reorient the output shaft in a different direction.

Manufacturer of standard and custom gear motors. Types are parallel shaft, hollow shaft offset, inverter duty, right angle, and washdown gearmotors.


Adding a gear-train to the output of any motor will reduce the speed, while simultaneously increasing torque. Gearing can be added to any type of motor. There is no need to waste time designing a geartrain and sourcing all the parts. Chances are, there is a gearmotor solution that you can drop right into your design.

Gear train construction ranges from simple plastic drive-trains for toys to beefy metal gear-trains for extra-high-torque applications.

Gear trains can be mated to brushed or brushless DC motors as well as steppers. Gear-train modules in a variety of gear ratios are available to fit standard NEMA sized steppers.




Gear words.png

· Rotational frequency, n

· Measured in rotation over time, such as RPM.

· Angular frequency, ω

· Measured in radians/second. 1 \mathrm{RPM} = \pi/30 rad/second

· Number of teeth, N

· How many teeth a gear has, an integer. In the case of worms, it is the number of thread starts that the worm has.

· Gear, wheel


External gear motors are the simplest and the cheapest answer to many "rotating demands" in oil hydraulics. And so, after taking the decision to "join the hydraulic brotherhood", every rookie learns what parts these motors have inside, how they generate torque, that there are unidirectional and bidirectional gear motors with their peculiarities, how to service these units (read - replace seals) and the rest of the bla-bla you find in any beginner's industrial hydraulics course. However - these motors possess one very interesting peculiarity that's never mentioned in catalogues or technical manuals, but which is extremely useful to be aware of, because from my personal experience and other tech's stories I can assure you that when this peculiarity "pops out" (it is rare to happen but itdoes happen) and one's not ready for it - lots of head-scratching is guaranteed. By saying "peculiarity" I am referring to the genetic predisposition of new external gear motors tostart-up stalling.


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