Cycloidal gearboxes
Cycloidal gearboxes or reducers contain four basic components: a high-speed input shaft, a single or substance cycloidal cam, cam followers or rollers, and a slow-speed output shaft. The input shaft attaches to an eccentric drive member that induces eccentric rotation of the cycloidal cam. In substance reducers, the first tabs on the cycloidal cam lobes engages cam fans in the casing. Cylindrical cam followers act as teeth on the inner gear, and the amount of cam supporters exceeds the amount of cam lobes. The second track of substance cam lobes engages with cam followers on the output shaft and transforms the cam’s eccentric rotation into concentric rotation of the result shaft, thus increasing torque and reducing acceleration.

Compound cycloidal gearboxes provide ratios ranging from as low as 10:1 to 300:1 without stacking levels, as in standard planetary gearboxes. The gearbox’s compound decrease and may be calculated using:

where nhsg = the number of followers or rollers in the fixed housing and nops = the number for followers or rollers in the gradual speed output shaft (flange).

There are several commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat treatment, and finishing procedures, cycloidal variations share simple design concepts but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made up of three fundamental force-transmitting elements: a sun gear, three or even more satellite or world gears, and an internal ring gear. In an average gearbox, the sun equipment attaches to the insight shaft, which is linked to the servomotor. The sun gear transmits electric motor rotation to the satellites which, in turn, rotate within the stationary ring gear. The ring gear is portion of the gearbox casing. Satellite gears rotate on rigid shafts connected to the earth carrier and trigger the planet carrier to rotate and, thus, turn the output shaft. The gearbox provides output shaft higher torque and lower rpm.

Planetary gearboxes generally have solitary or two-equipment stages for reduction ratios ranging from 3:1 to 100:1. A third stage can be added for actually higher ratios, but it is not common.

The ratio of a planetary gearbox is calculated using the following formula:where nring = the amount of teeth in the internal ring gear and nsun = the amount of teeth in the pinion (input) gear.
Comparing the two
When deciding between cycloidal and planetary gearboxes, engineers should initial consider the precision needed in the application. If backlash and positioning precision are crucial, then cycloidal gearboxes provide best choice. Removing backlash can also help the servomotor Cycloidal gearbox handle high-cycle, high-frequency moves.

Next, consider the ratio. Engineers can do this by optimizing the reflected load/gearbox inertia and acceleration for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes provide best torque density, weight, and precision. In fact, not many cycloidal reducers provide ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers may be used. Nevertheless, if the required ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking stages is unnecessary, so the gearbox could be shorter and less costly.
Finally, consider size. The majority of manufacturers offer square-framed planetary gearboxes that mate precisely with servomotors. But planetary gearboxes grow in length from single to two and three-stage designs as needed equipment ratios go from significantly less than 10:1 to between 11:1 and 100:1, and then to greater than 100:1, respectively.

Conversely, cycloidal reducers are bigger in diameter for the same torque yet are not as long. The compound reduction cycloidal gear train handles all ratios within the same deal size, so higher-ratio cycloidal equipment boxes become actually shorter than planetary variations with the same ratios.

Backlash, ratio, and size provide engineers with a preliminary gearbox selection. But selecting the most appropriate gearbox also entails bearing capacity, torsional stiffness, shock loads, environmental conditions, duty routine, and life.

From a mechanical perspective, gearboxes have become somewhat of accessories to servomotors. For gearboxes to perform properly and provide engineers with a balance of performance, lifestyle, and worth, sizing and selection should be determined from the strain side back again to the motor as opposed to the motor out.

Both cycloidal and planetary reducers work in any industry that uses servos or stepper motors. And even though both are epicyclical reducers, the differences between the majority of planetary gearboxes stem more from gear geometry and manufacturing processes instead of principles of operation. But cycloidal reducers are more diverse and share small in common with each other. There are advantages in each and engineers should think about the strengths and weaknesses when choosing one over the additional.

Great things about planetary gearboxes
• High torque density
• Load distribution and sharing between planet gears
• Smooth operation
• High efficiency
• Low input inertia
• Low backlash
• Low cost

Benefits of cycloidal gearboxes
• Zero or very-low backlash remains relatively constant during existence of the application
• Rolling rather than sliding contact
• Low wear
• Shock-load capacity
• Torsional stiffness
• Flat, pancake design
• Ratios exceeding 200:1 in a compact size
• Quiet operation
The necessity for gearboxes
There are three basic reasons to use a gearbox:

Inertia matching. The most typical reason for selecting a gearbox is to regulate inertia in highly powerful situations. Servomotors can only just control up to 10 times their personal inertia. But if response time is critical, the engine should control less than four instances its own inertia.

Speed reduction, Servomotors run more efficiently at higher speeds. Gearboxes help keep motors working at their optimal speeds.

Torque magnification. Gearboxes offer mechanical advantage by not only decreasing rate but also increasing output torque.

The EP 3000 and our related products that utilize cycloidal gearing technology deliver the most robust solution in the most compact footprint. The primary power train is comprised of an eccentric roller bearing that drives a wheel around a couple of inner pins, keeping the reduction high and the rotational inertia low. The wheel incorporates a curved tooth profile rather than the more traditional involute tooth profile, which eliminates shear forces at any point of contact. This style introduces compression forces, rather than those shear forces that would exist with an involute gear mesh. That provides several overall performance benefits such as for example high shock load capacity (>500% of rating), minimal friction and wear, lower mechanical service factors, among many others. The cycloidal design also has a huge output shaft bearing span, which provides exceptional overhung load capabilities without requiring any extra expensive components.

Cycloidal advantages over additional styles of gearing;

Able to handle larger “shock” loads (>500%) of rating compared to worm, helical, etc.
High reduction ratios and torque density in a concise dimensional footprint
Exceptional “built-in” overhung load carrying capability
High efficiency (>95%) per reduction stage
Minimal reflected inertia to motor for longer service life
Just ridiculously rugged since all get-out
The overall EP design proves to be extremely durable, and it requires minimal maintenance following installation. The EP is the most reliable reducer in the commercial marketplace, and it is a perfect fit for applications in heavy industry such as for example oil & gas, primary and secondary steel processing, commercial food production, metal cutting and forming machinery, wastewater treatment, extrusion equipment, among others.