Cycloidal gearboxes
Cycloidal gearboxes or reducers contain four fundamental components: a high-speed input shaft, an individual or compound 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 supporters 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 next track of compound cam lobes engages with cam fans on the output shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus raising torque and reducing acceleration.

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

where nhsg = the amount of followers or rollers in the fixed housing and nops = the quantity for followers or rollers in the sluggish speed 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 processes, cycloidal variations share simple design principles but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made 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. Sunlight gear transmits engine rotation to the satellites which, subsequently, rotate inside the stationary ring equipment. The ring equipment is portion of the gearbox casing. Satellite gears rotate on rigid shafts connected to the planet carrier and cause the planet carrier to rotate and, thus, turn the output shaft. The gearbox gives the output shaft higher torque and lower rpm.

Planetary gearboxes generally have single or two-equipment stages for reduction ratios which range from 3:1 to 100:1. A third stage could be added for even higher ratios, but it is not common.

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

Next, consider the ratio. Engineers can do this by optimizing the reflected load/gearbox inertia and velocity for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes provide best torque density, weight, and precision. Actually, few cycloidal reducers provide ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers can be used. However, if the required ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking phases is unnecessary, so the gearbox can be shorter and less expensive.
Finally, consider size. The majority of manufacturers provide square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes grow in length from one to two and three-stage styles 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 for as long. The compound reduction cycloidal gear train handles all ratios within the same deal size, therefore higher-ratio cycloidal gear boxes become also 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 capability, torsional stiffness, shock loads, environmental conditions, duty routine, and life.

From a mechanical perspective, gearboxes have grown to be somewhat of accessories to servomotors. For gearboxes to execute properly and provide engineers with a balance of performance, existence, and value, sizing and selection should be determined from the load side back again to the motor instead of the motor out.

Both cycloidal and planetary reducers work in virtually any industry that uses servos or stepper motors. And although both are epicyclical reducers, the differences between most planetary gearboxes stem more from equipment geometry and manufacturing procedures instead of principles of procedure. But cycloidal reducers are more varied and share small in common with one another. There are advantages in each and engineers should think about 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 remains relatively constant during life 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 common reason for choosing the gearbox is to control inertia in highly powerful circumstances. Servomotors can only just control up to 10 times their personal inertia. But if response time is critical, the electric motor should control significantly less than four times its own inertia.

Speed reduction, Servomotors operate more efficiently at higher Cycloidal gearbox speeds. Gearboxes help to keep motors working at their optimum speeds.

Torque magnification. Gearboxes offer mechanical advantage by not only decreasing acceleration 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 made up of an eccentric roller bearing that drives a wheel around a couple of internal 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 gets rid of shear forces at any stage of contact. This style introduces compression forces, rather than those shear forces that could can be found with an involute equipment mesh. That provides a number of efficiency benefits such as for example high shock load capability (>500% of ranking), minimal friction and use, lower mechanical service elements, among many others. The cycloidal style also has a large output shaft bearing span, which gives exceptional overhung load features without requiring any additional expensive components.

Cycloidal advantages over various other styles of gearing;

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