Cycloidal gearboxes
Cycloidal gearboxes or reducers consist of four simple 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 track of the cycloidal cam lobes engages cam followers in the casing. Cylindrical cam followers become teeth on the internal gear, and the number of cam supporters exceeds the number of cam lobes. The second 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 raising torque and reducing velocity.
Compound cycloidal gearboxes provide 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 number for followers or rollers in the sluggish 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 processes, cycloidal variations share basic design principles but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made of three basic force-transmitting elements: a sun gear, three or more satellite or world gears, and an internal ring gear. In a typical gearbox, the sun equipment attaches to the input shaft, which is connected to the servomotor. Sunlight gear transmits electric motor rotation to the satellites which, subsequently, rotate inside the stationary ring equipment. The ring equipment is part of the gearbox housing. Satellite gears rotate on rigid shafts linked to the earth carrier and cause the earth carrier to rotate and, thus, turn the result 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 also 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 number of teeth in the pinion (input) gear.
Comparing the two
When deciding between cycloidal and planetary gearboxes, engineers should first consider the precision needed in the application form. If backlash and positioning precision are crucial, then cycloidal gearboxes offer the most suitable choice. Removing backlash can also help the Cycloidal gearbox servomotor manage high-cycle, high-frequency moves.
Next, consider the ratio. Engineers can do that by optimizing the reflected load/gearbox inertia and speed for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the 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. Nevertheless, if the required ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking phases is unnecessary, therefore the gearbox could be shorter and less expensive.
Finally, consider size. Most manufacturers provide square-framed planetary gearboxes that mate exactly with servomotors. But planetary gearboxes develop in length from single to two and three-stage styles as needed gear 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 bundle size, so higher-ratio cycloidal gear boxes become even shorter than planetary variations with the same ratios.
Backlash, ratio, and size provide engineers with a preliminary gearbox selection. But deciding on the best gearbox also involves 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 stability of performance, life, and worth, sizing and selection should be determined from the load side back to the motor instead of 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 variations between the majority of planetary gearboxes stem more from gear geometry and manufacturing processes instead of principles of operation. But cycloidal reducers are more different and share little 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.
Benefits of planetary gearboxes
• High torque density
• Load distribution and posting between planet gears
• Smooth operation
• High efficiency
• Low input inertia
• Low backlash
• Low cost
Benefits of cycloidal gearboxes
• Zero or very-low backlash stays 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 typical reason for choosing the gearbox is to regulate inertia in highly dynamic situations. Servomotors can only control up to 10 times their very own inertia. But if response period is critical, the motor should control less than four times its own inertia.
Speed reduction, Servomotors operate more efficiently in higher speeds. Gearboxes help keep motors working at their optimal speeds.
Torque magnification. Gearboxes provide mechanical advantage by not merely decreasing rate 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 made up of an eccentric roller bearing that drives a wheel around a set 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 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 gear mesh. That provides a number of functionality benefits such as high shock load capacity (>500% of ranking), minimal friction and put on, lower mechanical service elements, among numerous others. The cycloidal style also has a big output shaft bearing period, 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 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 engine for longer service life
Just ridiculously rugged as all get-out
The overall EP design proves to be extremely durable, and it needs minimal maintenance following installation. The EP is the most reliable reducer in the industrial marketplace, in fact it is a perfect suit for applications in heavy industry such as for example oil & gas, primary and secondary metal processing, commercial food production, metal cutting and forming machinery, wastewater treatment, extrusion products, among others.