Cycloidal gearboxes
Cycloidal gearboxes or reducers contain four fundamental components: a high-speed input shaft, a single 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 track of the cycloidal cam lobes engages cam fans in the casing. Cylindrical cam followers become teeth on the inner gear, and the number of cam fans exceeds the number of cam lobes. The next track of substance cam lobes engages with cam fans on the output shaft and transforms the cam’s eccentric rotation into concentric rotation of the result shaft, thus raising torque and reducing quickness.
Compound cycloidal gearboxes offer ratios ranging from only 10:1 to 300:1 without stacking levels, as in regular planetary gearboxes. The gearbox’s compound reduction and will 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 are based on gear geometry, heat therapy, and finishing processes, cycloidal variations share simple design concepts but generate cycloidal movement in different ways.
Planetary gearboxes
Planetary gearboxes are made of three simple force-transmitting elements: a sun gear, three or more satellite or world gears, and an internal ring gear. In a typical gearbox, the sun gear attaches to the insight shaft, which is linked to the servomotor. Sunlight gear transmits motor rotation to the satellites which, in turn, rotate within the stationary ring equipment. The ring equipment is part of the gearbox housing. Satellite gears rotate on rigid shafts linked to the planet carrier and trigger the planet carrier to rotate and, thus, turn the output shaft. The gearbox provides output shaft higher torque and lower rpm.
Planetary gearboxes generally have single or two-equipment 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 amount 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 first consider the precision needed in the application form. If backlash and positioning accuracy are necessary, then cycloidal gearboxes provide best choice. Removing backlash may also help the servomotor deal with high-cycle, high-frequency moves.
Next, consider the ratio. Engineers can do that by optimizing the reflected load/gearbox inertia and quickness for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the best 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 may be used. However, if the mandatory ratio goes beyond 100:1, cycloidal gearboxes keep advantages because stacking stages is unnecessary, therefore the gearbox can be shorter and less costly.
Finally, consider size. Many manufacturers offer square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes grow in length from one to two and three-stage designs 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 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 package deal size, so higher-ratio cycloidal equipment boxes become also shorter than planetary variations with the same ratios.
Backlash, ratio, and size provide engineers with a preliminary 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 Cycloidal gearbox perspective, gearboxes have grown to be somewhat of accessories to servomotors. For gearboxes to execute properly and provide engineers with a balance of performance, existence, and value, sizing and selection should 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 most planetary gearboxes stem more from gear geometry and manufacturing processes instead of principles of procedure. But cycloidal reducers are more different and share small in common with each other. There are advantages in each and engineers should consider the strengths and weaknesses when choosing one over the other.
Benefits of 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 existence 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 need for gearboxes
There are three basic reasons to employ 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 personal inertia. But if response time is critical, the engine should control less than four moments its own inertia.
Speed reduction, Servomotors run more efficiently in higher speeds. Gearboxes help keep motors working at their optimum speeds.
Torque magnification. Gearboxes offer mechanical advantage by not merely decreasing velocity but also increasing output 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 made up of an eccentric roller bearing that drives a wheel around a set of internal pins, keeping the decrease 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 stage of contact. This design introduces compression forces, rather than those shear forces that would exist with an involute gear mesh. That provides numerous overall performance benefits such as high shock load capacity (>500% of rating), minimal friction and use, lower mechanical service factors, among many others. The cycloidal style also has a big output shaft bearing span, which provides exceptional overhung load features without requiring any additional expensive components.
Cycloidal advantages over various 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 electric motor for longer service life
Just ridiculously rugged because 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 dependable reducer in the industrial marketplace, and it is a perfect fit for applications in large industry such as for example oil & gas, primary and secondary metal processing, industrial food production, metal slicing and forming machinery, wastewater treatment, extrusion equipment, among others.