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 track of the cycloidal cam lobes engages cam fans in the housing. Cylindrical cam followers act as teeth on the inner gear, and the amount of cam followers 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 result shaft, thus increasing torque and reducing quickness.
Compound cycloidal gearboxes offer ratios ranging from as low as 10:1 to 300:1 without stacking stages, as in regular planetary gearboxes. The gearbox’s compound reduction and may be calculated using:
where nhsg = the number of followers or rollers in the fixed housing and nops = the quantity for followers or rollers in the slower quickness output shaft (flange).
There are several commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations derive from gear geometry, heat therapy, and finishing procedures, cycloidal variations share simple design principles but generate cycloidal motion in different ways.
Planetary gearboxes
Planetary gearboxes are made of three fundamental force-transmitting elements: a sun gear, three or even more satellite or planet gears, and an internal 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 within the stationary ring equipment. The ring equipment is area of the gearbox casing. Satellite gears rotate on rigid shafts connected to the planet carrier and cause the earth carrier to rotate and, thus, turn the output shaft. The gearbox gives the result shaft higher torque and lower rpm.
Planetary gearboxes generally have solitary or two-equipment Cycloidal gearbox 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 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 1st consider the precision needed in the application form. If backlash and positioning precision are crucial, then cycloidal gearboxes provide best choice. Removing backlash can also help the servomotor deal with high-cycle, high-frequency moves.
Following, 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 offer the greatest 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. Nevertheless, if the mandatory ratio goes beyond 100:1, cycloidal gearboxes keep advantages because stacking phases is unnecessary, so the gearbox could be shorter and less costly.
Finally, consider size. Most manufacturers provide square-framed planetary gearboxes that mate precisely with servomotors. But planetary gearboxes grow in length from one to two and three-stage styles as needed equipment ratios go from less than 10:1 to between 11:1 and 100:1, and to greater than 100:1, respectively.
Conversely, cycloidal reducers are larger in diameter for the same torque but are not for as long. The compound decrease cycloidal gear train handles all ratios within the same bundle size, so higher-ratio cycloidal equipment boxes become also shorter than planetary variations with the same ratios.
Backlash, ratio, and size provide engineers with an initial 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 become somewhat of accessories to servomotors. For gearboxes to execute properly and offer engineers with a stability 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 many planetary gearboxes stem more from equipment geometry and manufacturing procedures rather than principles of procedure. But cycloidal reducers are more different and share little in common with each other. There are advantages in each and engineers should consider the strengths and weaknesses when selecting one over the additional.
Great things about 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 stays relatively constant during lifestyle 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 employ a gearbox:
Inertia matching. The most typical reason for choosing the gearbox is to control inertia in highly dynamic situations. Servomotors can only control up to 10 times their own inertia. But if response time is critical, the electric motor should control significantly less than four occasions its own inertia.
Speed reduction, Servomotors run more efficiently at higher speeds. Gearboxes help to keep motors working at their optimal speeds.
Torque magnification. Gearboxes provide mechanical advantage by not only decreasing speed but also increasing result 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 comprised 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 rather than 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 equipment mesh. That provides a number of functionality benefits such as high shock load capability (>500% of ranking), minimal friction and wear, lower mechanical service factors, among numerous others. The cycloidal design also has a large output shaft bearing period, which provides exceptional overhung load capabilities without requiring any additional 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 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 since all get-out
The overall EP design proves to be extremely durable, and it needs minimal maintenance following installation. The EP may be the most reliable reducer in the commercial marketplace, and it is a perfect fit for applications in heavy industry such as for example oil & gas, main and secondary steel processing, commercial food production, metal cutting and forming machinery, wastewater treatment, extrusion tools, among others.