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Cycloidal gearbox cycloidal gearboxes
Cycloidal gearboxes or reducers consist of 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 track of the cycloidal cam lobes engages cam supporters in the housing. Cylindrical cam followers become teeth on the inner gear, and the amount of cam supporters exceeds the amount of cam lobes. The next track of substance cam lobes engages with cam followers on the result shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus increasing torque and reducing velocity.

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 reduction and may be calculated using:

where nhsg = the amount of followers or rollers in the fixed housing and nops = the number for followers or rollers in the slow rate 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 fundamental design principles but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made 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 gear attaches to the insight shaft, which is linked to the servomotor. Sunlight gear transmits electric motor rotation to the satellites which, subsequently, rotate in the stationary ring gear. The ring equipment is section of the gearbox housing. Satellite gears rotate on rigid shafts connected to the earth 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-gear 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 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. If backlash and positioning accuracy are necessary, then cycloidal gearboxes provide best choice. Removing backlash can also help the servomotor manage 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 greatest torque density, weight, and precision. Actually, not many cycloidal reducers offer ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers may be used. Nevertheless, if the mandatory ratio goes beyond 100:1, cycloidal gearboxes keep advantages because stacking phases is unnecessary, therefore the gearbox can be shorter and less expensive.
Finally, consider size. Many manufacturers provide square-framed planetary gearboxes that mate exactly with servomotors. But planetary gearboxes grow in length from single to two and three-stage designs as needed gear ratios go from less than 10:1 to between 11:1 and 100:1, and then to higher than 100:1, respectively.

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

Backlash, ratio, and size provide engineers with an initial gearbox selection. But deciding on the best gearbox also involves 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 stability of performance, life, and value, sizing and selection should be determined from the strain side back to the motor instead of 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 most planetary gearboxes stem more from gear geometry and manufacturing procedures rather than 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 selecting one over the various 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 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 concise 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 regulate inertia in highly dynamic circumstances. Servomotors can only just control up to 10 times their own inertia. But if response period is critical, the engine should control significantly less than four instances its own inertia.

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

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

The EP 3000 and our related products that use 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 internal pins, keeping the reduction high and the rotational inertia low. The wheel includes a curved tooth profile instead of the more traditional involute tooth profile, which eliminates shear forces at any stage of contact. This design introduces compression forces, rather than those shear forces that could can be found with an involute gear mesh. That provides numerous performance benefits such as high shock load capability (>500% of ranking), minimal friction and wear, lower mechanical service elements, among numerous others. The cycloidal style also has a large output shaft bearing span, which gives 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 in comparison 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 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 commercial marketplace, in fact it is a perfect suit for applications in heavy industry such as for example oil & gas, main and secondary steel processing, industrial food production, metal slicing and forming machinery, wastewater treatment, extrusion devices, among others.