The function of gearing is to mesh with other gear elements to transmit altered torque and rotation. In fact, gearing can change the speed, torque, and direction of motion from a drive source. 

In this Motion Control Classroom, we detail the most common gear types for motion applications — as well as the contained gear trains known as gearboxes (those mechanical components consisting of a series of integrated gears) and other iterations to simplify integration and servotuning. 

Topics include various gear subtypes and geometries as well as those related to gearing for washdown settings, exceptionally demanding motion designs, shaft-mount designs, and axes needing servogearing customization.

Lisa Eitel

Executive Editor, Design World

Gearing Classroom Sponsored by


What are gears for power transmission?

Spur gears: What are they and where are they used?

Hypoid gearboxes: What are they and where are they used?

Wave and cycloidal gearing explained

The function of a gear is to mesh with other gears to transmit altered torque and rotation. In fact, gearing can change the speed, torque and direction of motion from a drive source.

Spur gears are a type of cylindrical gear, with shafts that are parallel and coplanar, and teeth that are straight and oriented parallel to the shafts. 

Hypoid gearboxes are a type of spiral bevel gearbox, with the difference that hypoid gears have axes that are non-intersecting and not parallel. 

Many of today’s precision applications necessitate gears capable of dramatic speed reductions, power densities, and transmission accuracies. 

What’s the best type of gearbox for servo applications?

Gearboxes provide torque multiplication, speed reduction, and inertia matching for motor-driven systems. Servo systems, specifically, require gearboxes that can supply not only high torque with low added inertia, but also high precision and stiffness. One type of gearbox meets all these criteria while providing relatively long operating life with low maintenance requirements — the planetary gearbox.

What are the drawbacks to using a planetary gearbox?

One type of gearbox meets all the design criteria of servo applications while providing relatively long operating life with low maintenance requirements — the planetary gearbox. That’s because planetary gearboxes offer high torque transmission with good stiffness and low noise in a footprint that’s more compact than that of other gearbox types.


What features make a gearbox suitable for washdown environments?

Trends in gears and gearmotors for eMobility, washdown & customization

CGI Inc. now offers new Raptor-SS IP69K-rated precision planetary gearheads

Washdown processes are common in the food and beverage and pharmaceutical industries, where cleanliness of the manufacturing and handling equipment plays an important role in the quality and safety of the product. 

The fundamental mode of operation for gearing and its transmission of mechanical power remains unchanged — as has that for the electric motors with which they pair. 

CGI Inc., a leading manufacturer of custom precision gearboxes and mechanical subassemblies, now sells a new line of IP69K-rated precision planetary gearheads. 

New large, hollow-shaft gear units from Harmonic Drive

The new FBS-2UH gear unit series from Harmonic Drive features a large, hollow shaft with a compact outer diameter. The extra large hollow shaft is suitable for robots and machines requiring complex cabling to pass through the axis of rotation.


Choosing a drive involves several design factors that depend greatly on the task at hand. Download this PDF from Harmonic Drive to learn more!

Harmonic Drive releases HPN-RA harmonic planetary right angle value series gearhead

The popular HPN Harmonic Planetary value series from Harmonic Drive LLC is now available in a right angle configuration. The HPN-RA provides a low cost solution without the need to compromise on quality or performance. 

CGI Product Configurators & 3D Models

Quickly configure and select the right gearbox for your application. This step by step process will produce a part number, description and generate a 3D CAD model for use in any CAD package. Individual configurators available by CGI product family for ease of use


What are the signs of gearbox misalignment?

What is pitch line velocity and why is it important?

When to use gears to change the inertia ratio of a motor-driven system

Gearbox misalignment is widely recognized as the underlying cause for the majority of gearbox repairs and failures. It can degrade machine performance, reduce mean time between repair (MTBR), and decrease the operating life of the gearbox, motor, and driven equipment.

Looking back at some origins of gear customization

In gearbox sizing, it’s important to determine the required input speed in rpm and ensure that it doesn’t exceed the gearbox’s maximum speed capability. But the linear velocity of the gear teeth, known as pitch line velocity, also plays a significant role in gearbox performance.

In any system where a motor drives a load to achieve precise positioning, velocity, or torque, the ratio of the load inertia to the motor inertia plays a significant role in determining the motor’s ability to effectively and efficiently control the load.

Power-transmission devices are increasingly customized, and gearsets and gearmotors are no exception.

Harmonic Drive’s mission is to provide motion control solutions that give our customers a competitive advantage. To accomplish this we continually invest in the growth of our employees and in our company’s capabilities.

Harmonic Drive LLC engineers and manufactures precision servo actuators, gearheads and gear component sets. We work closely with both Fortune 500 and companies of all sizes to understand their application requirements and provide a standard or, in most cases, a custom-engineered solution to enable the success of their design project.

Since 1967, CGI has consistently been providing for its customers exceptional craftsmanship and outstanding customer service. This unwavering commitment is what makes CGI the reliable choice for precision components and sub-assemblies.

CGI's capabilities in precision manufacturing feature a careful blend of cutting edge technology and renowned reliability.

We are able to provide our customers with an engineering team that is talented, knowledgeable and eager to help. We can work with your concept from the prototype stage all the way through to full production.