Cycloidal gearboxes
Cycloidal gearboxes or reducers contain four basic components: a high-speed input shaft, a single 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 fans in the casing. Cylindrical cam followers act as teeth on the internal gear, and the amount of cam supporters exceeds the number of cam lobes. The second track of substance cam lobes engages with cam fans on the result 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 as low as 10:1 to 300:1 without stacking levels, as in standard planetary gearboxes. The gearbox’s compound decrease and will 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 gradual acceleration output shaft (flange).

There are many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat treatment, and finishing procedures, cycloidal variations share basic design principles but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made up of three simple force-transmitting elements: a sun gear, three or more satellite or world gears, and an interior ring gear. In an average gearbox, the sun equipment attaches to the input shaft, which is linked to the servomotor. Sunlight gear transmits motor rotation to the satellites which, subsequently, rotate inside the stationary ring gear. The ring gear is section of the gearbox casing. Satellite gears rotate on rigid shafts linked to the planet carrier and cause the planet carrier to rotate and, thus, turn the result shaft. The gearbox gives the output shaft higher torque and lower rpm.

Planetary gearboxes generally have single or two-equipment Cycloidal gearbox 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 next formula:where nring = the amount of teeth in the inner ring gear and nsun = the amount of teeth in the pinion (input) gear.
Comparing the two
When deciding among cycloidal and planetary gearboxes, engineers should initial consider the precision needed in the application form. If backlash and positioning precision are crucial, then cycloidal gearboxes provide most suitable choice. Removing backlash may also help the servomotor deal with high-cycle, high-frequency moves.

Following, consider the ratio. Engineers can do that 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. In fact, not many cycloidal reducers offer ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers can be used. However, if the mandatory 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 exactly with servomotors. But planetary gearboxes develop 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 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 package deal size, therefore higher-ratio cycloidal gear boxes become actually shorter than planetary versions with the same ratios.

Backlash, ratio, and size provide engineers with an initial gearbox selection. But selecting the most appropriate gearbox also involves bearing capacity, torsional stiffness, shock loads, environmental conditions, duty cycle, and life.

From a mechanical perspective, gearboxes have grown to be somewhat of accessories to servomotors. For gearboxes to execute properly and offer engineers with a balance of performance, existence, 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 are appropriate in 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 rather than principles of procedure. But cycloidal reducers are more different and share small in common with each other. There are advantages in each and engineers should consider the strengths and weaknesses when selecting one over the other.

Great things about planetary gearboxes
• High torque density
• Load distribution and posting 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 life of the application
• Rolling instead of sliding contact
• Low wear
• Shock-load capacity
• Torsional stiffness
• Flat, pancake design
• Ratios exceeding 200:1 in a concise size
• Quiet operation
The need 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 dynamic situations. Servomotors can only just control up to 10 times their own inertia. But if response period is critical, the electric motor should control less than four situations its own inertia.

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

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

The EP 3000 and our related products that make use of 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 inner pins, keeping the decrease high and the rotational inertia low. The wheel incorporates a curved tooth profile instead of the more traditional involute tooth profile, which gets rid of shear forces at any stage of contact. This style introduces compression forces, instead of those shear forces that would 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 put on, lower mechanical service elements, among numerous others. The cycloidal style also has a huge output shaft bearing span, which provides exceptional overhung load capabilities without requiring any extra expensive components.

Cycloidal advantages over other styles of gearing;

Capable of handling 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 because all get-out
The entire EP design proves to be extremely durable, and it requires minimal maintenance following installation. The EP is the most reliable reducer in the industrial marketplace, and it is a perfect suit for applications in weighty industry such as oil & gas, major and secondary metal processing, industrial food production, metal slicing and forming machinery, wastewater treatment, extrusion equipment, among others.