Cycloidal gearboxes or reducers contain four fundamental components: a high-speed input shaft, a single 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 substance reducers, the first an eye on the cycloidal cam lobes engages cam followers in the housing. Cylindrical cam followers act as teeth on the inner gear, and the amount of cam fans exceeds the amount of cam lobes. The next track of compound 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 rate.
Compound cycloidal gearboxes provide ratios ranging from only 10:1 to 300:1 without stacking phases, as in standard planetary gearboxes. The gearbox’s compound decrease and may 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 rate output shaft (flange).
There are many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations derive from gear geometry, heat treatment, and finishing procedures, cycloidal variations share simple design concepts but generate cycloidal movement in different ways.
Planetary gearboxes are made up 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 gear attaches to the insight shaft, which is connected to the servomotor. Sunlight gear transmits electric motor rotation to the satellites which, subsequently, rotate within the stationary ring gear. The ring equipment is area of the gearbox housing. Satellite gears rotate on rigid shafts linked to the planet carrier and cause the planet carrier to rotate and, thus, turn the output shaft. The gearbox provides result shaft higher torque and lower rpm.
Planetary gearboxes generally have single or two-gear stages for reduction ratios ranging from 3:1 to 100:1. A third stage could be added for actually higher ratios, nonetheless 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 among cycloidal and planetary gearboxes, engineers should 1st consider the precision needed in the application form. If backlash and positioning precision are necessary, then cycloidal gearboxes provide most suitable choice. Removing backlash may also help the servomotor manage high-cycle, high-frequency moves.
Following, 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. Nevertheless, if the required ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking levels is unnecessary, therefore the gearbox can be shorter and less costly.
Finally, consider size. Many manufacturers offer square-framed planetary gearboxes that mate precisely with servomotors. But planetary gearboxes develop in length from one 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 higher than 100:1, respectively.
Conversely, cycloidal reducers are bigger in diameter for the same torque yet are not for as long. The compound decrease cycloidal gear teach handles all ratios within the same package size, therefore higher-ratio cycloidal equipment boxes become also shorter than planetary versions with the same ratios.
Backlash, ratio, and size provide engineers with a preliminary gearbox selection. But deciding on the best gearbox also consists of 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 execute properly and offer engineers with a balance of performance, existence, and value, sizing and selection ought to be determined from the strain side back again to the motor as opposed to the motor out.
Both cycloidal and planetary reducers work in virtually any industry that uses servos or stepper motors. And although both are epicyclical reducers, the distinctions between the majority of planetary gearboxes stem more from gear geometry and manufacturing procedures rather than principles of operation. But cycloidal reducers are more diverse and share little in common with one another. There are advantages in each and engineers should think about the strengths and weaknesses when choosing one over the additional.
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
Benefits of 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 necessity for gearboxes
There are three basic Cycloidal gearbox reasons to employ a gearbox:
Inertia matching. The most common reason for selecting a gearbox is to control inertia in highly dynamic situations. Servomotors can only control up to 10 times their personal inertia. But if response period is critical, the electric motor should control less than four situations its own inertia.
Speed reduction, Servomotors operate more efficiently at higher speeds. Gearboxes help to keep motors working at their optimal speeds.
Torque magnification. Gearboxes offer mechanical advantage by not only decreasing quickness 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 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 gets rid of shear forces at any stage of contact. This design introduces compression forces, rather than those shear forces that would exist with an involute equipment mesh. That provides numerous efficiency benefits such as high shock load capacity (>500% of ranking), minimal friction and put on, lower mechanical service factors, among numerous others. The cycloidal style also has a sizable output shaft bearing period, which provides exceptional overhung load capabilities without requiring any additional expensive components.
Cycloidal advantages over additional styles of gearing;
Able to handle larger “shock” loads (>500%) of rating compared 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 motor for longer service life
Just ridiculously rugged since all get-out
The overall EP design proves to be extremely durable, and it requires minimal maintenance following installation. The EP is the most dependable reducer in the commercial marketplace, and it is a perfect suit for applications in heavy industry such as oil & gas, major and secondary steel processing, industrial food production, metal reducing and forming machinery, wastewater treatment, extrusion products, among others.