Cycloidal gearboxes or reducers contain 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 insight shaft attaches to an eccentric drive member that induces eccentric rotation of the cycloidal cam. In compound reducers, the first an eye on the cycloidal cam lobes engages cam supporters in the casing. Cylindrical cam followers become teeth on the internal gear, and the amount of cam followers exceeds the amount of cam lobes. The next track of substance cam lobes engages with cam followers on the result shaft and transforms the cam’s eccentric rotation into concentric rotation of the result shaft, thus raising torque and reducing speed.
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 can 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 sluggish swiftness output shaft (flange).
There are several commercial Cycloidal gearbox 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 motion in different ways.
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 a typical gearbox, the sun equipment attaches to the insight shaft, which is linked to the servomotor. The sun gear transmits engine rotation to the satellites which, subsequently, rotate in the stationary ring equipment. The ring gear is section 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 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 which range from 3:1 to 100:1. A third stage could be added for also higher ratios, but it is not common.
The ratio of a planetary gearbox is calculated using the next formula:where nring = the amount of teeth in the inner ring gear and nsun = the number of teeth in the pinion (input) gear.
Comparing the two
When deciding between cycloidal and planetary gearboxes, engineers should initial consider the precision needed in the application. If backlash and positioning precision are necessary, then cycloidal gearboxes offer the 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 velocity for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the greatest torque density, weight, and precision. In fact, 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 mandatory ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking levels is unnecessary, so the gearbox could be shorter and less costly.
Finally, consider size. The majority of manufacturers provide 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 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 bundle size, therefore higher-ratio cycloidal gear boxes become also shorter than planetary variations with the same ratios.
Backlash, ratio, and size provide engineers with an initial gearbox selection. But choosing the right gearbox also requires bearing capability, torsional stiffness, shock loads, environmental conditions, duty routine, and life.
From a mechanical perspective, gearboxes have grown to be somewhat of accessories to servomotors. For gearboxes to perform properly and provide engineers with a balance of performance, existence, and value, sizing and selection ought to be determined from the load side back to the motor instead of the motor out.
Both cycloidal and planetary reducers are appropriate in any industry that uses servos or stepper motors. And although both are epicyclical reducers, the variations between the majority of planetary gearboxes stem more from gear geometry and manufacturing procedures rather than principles of procedure. But cycloidal reducers are more varied and share little in common with each other. There are advantages in each and engineers should think about the strengths and weaknesses when selecting one over the other.
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 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 compact size
• Quiet operation
The necessity for gearboxes
There are three basic reasons to employ a gearbox:
Inertia matching. The most common reason for choosing the gearbox is to control inertia in highly powerful situations. Servomotors can only just control up to 10 times their own inertia. But if response time is critical, the motor should control significantly less than four occasions its own inertia.
Speed reduction, Servomotors operate more efficiently at higher speeds. Gearboxes help to keep motors working at their optimum speeds.
Torque magnification. Gearboxes offer mechanical advantage by not only decreasing acceleration 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 primary power train is comprised of an eccentric roller bearing that drives a wheel around a set 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 gets rid of shear forces at any point of contact. This style introduces compression forces, rather than those shear forces that would exist with an involute gear mesh. That provides numerous performance benefits such as high shock load capability (>500% of ranking), minimal friction and put on, lower mechanical service factors, among numerous others. The cycloidal design also has a big output shaft bearing span, which gives exceptional overhung load capabilities without requiring any extra expensive components.
Cycloidal advantages over various other 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 concise 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 because all get-out
The entire EP design proves to be extremely durable, and it needs minimal maintenance following installation. The EP may be the most reliable reducer in the industrial marketplace, and it is a perfect suit for applications in large industry such as oil & gas, major and secondary steel processing, commercial food production, metal cutting and forming machinery, wastewater treatment, extrusion tools, among others.