Cycloidal gearboxes
Cycloidal gearboxes or reducers consist of four basic components: a high-speed input shaft, an individual or compound cycloidal cam, cam followers or rollers, and a slow-speed output shaft. The insight 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 followers in the casing. Cylindrical cam followers act as teeth on the internal gear, and the amount of cam followers exceeds the number of cam lobes. The second track of compound cam lobes engages with cam supporters on the result shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus raising torque and reducing swiftness.

Compound cycloidal gearboxes offer ratios ranging from only 10:1 to 300:1 without stacking stages, as in regular planetary gearboxes. The gearbox’s compound reduction and can 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 velocity output shaft (flange).

There are several commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations derive from 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 basic force-transmitting elements: a sun gear, three or even more satellite or world gears, and an interior ring gear. In a typical gearbox, the sun equipment attaches to the input shaft, which is linked to the servomotor. The sun gear transmits engine rotation to the satellites which, subsequently, rotate inside the stationary ring equipment. The ring gear is section of the gearbox housing. Satellite gears rotate on rigid shafts connected to the planet carrier and cause the earth carrier to rotate and, thus, turn the output shaft. The gearbox provides output shaft higher torque and lower rpm.

Planetary gearboxes generally have one or two-gear stages for reduction ratios ranging from 3:1 to 100:1. A third stage can be added for even higher ratios, nonetheless it is not common.

The ratio of a planetary gearbox is calculated using the following formula:where nring = the amount of teeth in the inner ring gear and nsun = the number of teeth in the pinion (input) gear.
Comparing the two
When deciding between cycloidal and planetary gearboxes, engineers should 1st consider the precision needed in the application. If backlash and positioning accuracy are necessary, then cycloidal gearboxes provide best choice. Removing backlash can also help the servomotor Cycloidal gearbox handle high-cycle, high-frequency moves.

Following, consider the ratio. Engineers can do this by optimizing the reflected load/gearbox inertia and quickness for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the 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 can be used. Nevertheless, if the required ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking stages is unnecessary, therefore the gearbox could be shorter and less costly.
Finally, consider size. The majority of manufacturers provide square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes develop in length from single to two and three-stage designs as needed gear ratios go from significantly less than 10:1 to between 11:1 and 100:1, and to greater than 100:1, respectively.

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

Backlash, ratio, and size provide engineers with an initial gearbox selection. But deciding on the best gearbox also requires bearing capability, torsional stiffness, shock loads, environmental conditions, duty cycle, 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, life, and worth, sizing and selection ought to be determined from the strain side back again to the motor as opposed to the motor out.

Both cycloidal and planetary reducers are appropriate in any industry that uses servos or stepper motors. And even though both are epicyclical reducers, the variations between the majority of planetary gearboxes stem more from equipment geometry and manufacturing processes instead of principles of procedure. But cycloidal reducers are more diverse and share little in common with one another. There are advantages in each and engineers should consider the strengths and weaknesses when selecting one over the various other.

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

Great things about cycloidal gearboxes
• Zero or very-low backlash stays relatively constant during existence of the application
• Rolling instead of 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 choosing the gearbox is to regulate inertia in highly powerful situations. Servomotors can only just control up to 10 times their own inertia. But if response time is critical, the electric motor should control less than four instances its own inertia.

Speed reduction, Servomotors operate more efficiently at higher speeds. Gearboxes help to keep motors operating at their ideal speeds.

Torque magnification. Gearboxes offer mechanical advantage by not only decreasing speed but also increasing result torque.

The EP 3000 and our related products that utilize cycloidal gearing technology deliver the most robust solution in the most compact footprint. The main power train is comprised of an eccentric roller bearing that drives a wheel around a set of inner pins, keeping the decrease high and the rotational inertia low. The wheel includes a curved tooth profile rather than the more traditional involute tooth profile, which removes shear forces at any point of contact. This style introduces compression forces, rather than those shear forces that would can be found with an involute equipment mesh. That provides several functionality benefits such as high shock load capability (>500% of rating), minimal friction and put on, lower mechanical service factors, among many others. The cycloidal style also has a sizable output shaft bearing span, which gives exceptional overhung load features without requiring any additional expensive components.

Cycloidal advantages over other 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 engine for longer service life
Just ridiculously rugged as all get-out
The overall EP design proves to be extremely durable, and it requires minimal maintenance following installation. The EP may be the most dependable reducer in the commercial marketplace, and it is a perfect suit for applications in heavy industry such as for example oil & gas, primary and secondary metal processing, industrial food production, metal reducing and forming machinery, wastewater treatment, extrusion products, among others.