Cycloidal gearboxes or reducers consist of four basic 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 casing. Cylindrical cam followers act as teeth on the internal gear, and the amount of cam supporters exceeds the number of cam lobes. The second track of compound cam lobes engages with cam supporters on the result shaft and transforms the cam’s eccentric rotation into concentric rotation of the result shaft, thus raising torque and reducing swiftness.
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 may be calculated using:
where nhsg = the amount of followers or rollers in the fixed housing and nops = the quantity for followers or rollers in the gradual acceleration 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 simple design concepts but generate cycloidal motion in different ways.
Planetary gearboxes are made of three simple force-transmitting elements: a sun gear, three or even more satellite or planet gears, and an interior ring gear. In an average gearbox, the sun equipment attaches to the insight shaft, which is connected to the servomotor. The sun gear transmits engine rotation to the satellites which, in turn, rotate within the stationary ring gear. The ring gear is portion of the Cycloidal gearbox gearbox housing. Satellite gears rotate on rigid shafts linked to the earth carrier and trigger 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 ranging from 3:1 to 100:1. A third stage could be added for also higher ratios, nonetheless it is not common.
The ratio of a planetary gearbox is calculated using the following 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 among cycloidal and planetary gearboxes, engineers should first consider the precision needed in the application. If backlash and positioning accuracy are crucial, then cycloidal gearboxes provide most suitable choice. Removing backlash may 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 speed 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 provide 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 hold advantages because stacking stages is unnecessary, therefore the gearbox can be shorter and less costly.
Finally, consider size. The majority of manufacturers offer square-framed planetary gearboxes that mate precisely with servomotors. But planetary gearboxes develop in length from solitary to two and three-stage designs as needed equipment 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 larger in diameter for the same torque yet are not for as long. The compound reduction cycloidal gear teach handles all ratios within the same deal size, so higher-ratio cycloidal equipment boxes become even 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 offer engineers with a balance of performance, existence, and worth, 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 even though both are epicyclical reducers, the differences between many planetary gearboxes stem more from gear geometry and manufacturing procedures rather than principles of procedure. But cycloidal reducers are more different and share small in common with one another. There are advantages in each and engineers should consider the strengths and weaknesses when selecting one over the additional.
Benefits of planetary gearboxes
• High torque density
• Load distribution and sharing 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 concise size
• Quiet operation
The necessity for gearboxes
There are three basic reasons to use a gearbox:
Inertia matching. The most common reason for selecting a gearbox is to control inertia in highly powerful situations. Servomotors can only just control up to 10 times their personal inertia. But if response time is critical, the motor should control significantly less than four occasions its own inertia.
Speed reduction, Servomotors run more efficiently in higher speeds. Gearboxes help to keep motors operating at their ideal 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 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 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 eliminates shear forces at any point of contact. This style introduces compression forces, rather than those shear forces that would exist with an involute equipment mesh. That provides several efficiency benefits such as for example high shock load capacity (>500% of ranking), minimal friction and use, lower mechanical service elements, among numerous others. The cycloidal design also has a large output shaft bearing period, which gives exceptional overhung load capabilities without requiring any extra expensive components.
Cycloidal advantages over various 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 concise dimensional footprint
Exceptional “built-in” overhung load carrying capability
High efficiency (>95%) per reduction stage
Minimal reflected inertia to electric motor 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 industrial marketplace, and it is a perfect fit for applications in heavy industry such as for example oil & gas, major and secondary metal processing, commercial food production, metal cutting and forming machinery, wastewater treatment, extrusion products, among others.