Cycloidal gearboxes
Cycloidal gearboxes or reducers consist of four simple components: a high-speed input shaft, an individual or substance 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 compound reducers, the first tabs on the cycloidal cam lobes engages cam fans in the housing. Cylindrical cam followers become teeth on the internal gear, and the amount of cam supporters exceeds the number of cam lobes. The next track of substance cam lobes engages with cam supporters on the output 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 phases, as in regular planetary gearboxes. The gearbox’s compound decrease and will 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 slower speed output shaft (flange).
There are many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat therapy, and finishing processes, cycloidal variations share basic design concepts 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 planet gears, and an internal ring gear. In a typical gearbox, the sun equipment attaches to the insight 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 part of the gearbox casing. Satellite gears rotate on rigid shafts connected to the earth 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-gear stages for reduction ratios which range 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 next formula:where nring = the number of teeth in the inner ring gear and nsun = the amount of teeth in the pinion (input) gear.
Comparing the two
When deciding between cycloidal and planetary gearboxes, engineers should Cycloidal gearbox initial consider the precision needed in the application. If backlash and positioning precision are necessary, then cycloidal gearboxes offer the best choice. Removing backlash can also help the servomotor handle high-cycle, high-frequency moves.
Next, consider the ratio. Engineers can do this by optimizing the reflected load/gearbox inertia and swiftness for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the greatest torque density, weight, and precision. Actually, few 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 keep advantages because stacking levels is unnecessary, so the gearbox can be shorter and less costly.
Finally, consider size. Many manufacturers offer square-framed planetary gearboxes that mate exactly with servomotors. But planetary gearboxes grow in length from one to two and three-stage styles as needed gear ratios go from 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 but are not as long. The compound reduction cycloidal gear teach handles all ratios within the same package size, so higher-ratio cycloidal gear boxes become actually 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 involves bearing capability, 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 offer engineers with a balance of performance, existence, and worth, sizing and selection ought to be determined from the load side back again to the motor as opposed to the motor out.
Both cycloidal and planetary reducers are appropriate in virtually any industry that uses servos or stepper motors. And even though both are epicyclical reducers, the distinctions between the majority of planetary gearboxes stem more from gear geometry and manufacturing processes rather than principles of operation. But cycloidal reducers are more different and share little in common with one another. There are advantages in each and engineers should consider the strengths and weaknesses when choosing 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 remains relatively constant during lifestyle 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 control inertia in highly dynamic circumstances. Servomotors can only just control up to 10 times their personal 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 to keep motors working at their optimum speeds.
Torque magnification. Gearboxes provide mechanical advantage by not only decreasing acceleration but also increasing output torque.
The EP 3000 and our related products that use 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 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 for example high shock load capability (>500% of rating), minimal friction and put on, lower mechanical service elements, among many others. The cycloidal design also has a sizable output shaft bearing span, which gives exceptional 
overhung load capabilities without requiring any extra expensive components.
Cycloidal advantages over 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 concise dimensional footprint
Exceptional “built-in” overhung load carrying capability
High efficiency (>95%) per reduction stage
Minimal reflected inertia to motor for longer service life
Just ridiculously rugged since all get-out
The overall 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, primary and secondary steel processing, commercial food production, metal slicing and forming machinery, wastewater treatment, extrusion gear, among others.