Cycloidal gearboxes or reducers consist of four fundamental components: a high-speed input shaft, an individual or compound cycloidal cam, cam followers or rollers, and a slow-speed output shaft. The input shaft attaches to an eccentric drive member that induces eccentric rotation of the cycloidal cam. In substance 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 number of cam followers exceeds the amount of cam lobes. The second 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 result shaft, thus raising Cycloidal gearbox torque and reducing acceleration.
Compound cycloidal gearboxes provide ratios ranging from as low as 10:1 to 300:1 without stacking phases, as in regular planetary gearboxes. The gearbox’s compound reduction 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 gradual velocity output shaft (flange).
There are many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations derive from gear geometry, heat therapy, and finishing procedures, cycloidal variations share fundamental design concepts but generate cycloidal movement in different ways.
Planetary gearboxes are made up of three simple 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 connected to the servomotor. The sun gear transmits engine rotation to the satellites which, subsequently, rotate within the stationary ring equipment. The ring gear is portion of the gearbox housing. Satellite gears rotate on rigid shafts connected to the earth carrier and cause the earth carrier to rotate and, thus, turn the result shaft. The gearbox provides result shaft higher torque and lower rpm.
Planetary gearboxes generally have one or two-equipment stages for reduction ratios which range from 3:1 to 100:1. A third stage could be added for even 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 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 form. If backlash and positioning accuracy are crucial, then cycloidal gearboxes offer the most suitable 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 velocity for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes provide greatest torque density, weight, and precision. Actually, 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 levels is unnecessary, therefore the gearbox could be shorter and less expensive.
Finally, consider size. Many manufacturers provide square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes grow in length from single 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 bigger in diameter for the same torque yet are not as long. The compound reduction cycloidal gear train handles all ratios within the same package deal size, therefore 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 requires 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 balance of performance, life, and worth, sizing and selection ought to be determined from the strain side back again to the motor instead of the motor out.
Both cycloidal and planetary reducers work in any industry that uses servos or stepper motors. And although both are epicyclical reducers, the differences between most planetary gearboxes stem more from equipment geometry and manufacturing procedures instead of principles of operation. But cycloidal reducers are more diverse 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
Benefits of cycloidal gearboxes
• Zero or very-low backlash stays 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 concise size
• Quiet operation
The necessity for gearboxes
There are three basic reasons to use a gearbox:
Inertia matching. The most typical reason for selecting a gearbox is to regulate inertia in highly dynamic circumstances. Servomotors can only control up to 10 times their own inertia. But if response time is critical, the engine should control less than four situations its own inertia.
Speed reduction, Servomotors run 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 swiftness 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 reduction high and the rotational inertia low. The wheel includes a curved tooth profile rather than 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 could exist with an involute equipment mesh. That provides a number of performance benefits such as high shock load capability (>500% of rating), minimal friction and wear, lower mechanical service factors, 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 additional 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 since all get-out
The entire EP design proves to be extremely durable, and it requires minimal maintenance following installation. The EP may be the most dependable reducer in the industrial marketplace, in fact it is a perfect suit for applications in large industry such as for example oil & gas, principal and secondary metal processing, commercial food production, metal trimming and forming machinery, wastewater treatment, extrusion devices, among others.