Cycloidal gearboxes or reducers consist of 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 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 followers in the housing. Cylindrical cam followers become teeth on the internal gear, and the number of cam fans exceeds the amount of cam lobes. The second track of substance cam lobes engages with cam followers 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 phases, 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 sluggish swiftness output shaft (flange).
There are several commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations derive from gear geometry, heat therapy, 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 world gears, and an interior ring gear. In a typical gearbox, the sun gear attaches to the insight shaft, which is linked to the servomotor. Sunlight gear transmits engine rotation to the satellites which, in turn, rotate inside the stationary ring equipment. The ring equipment is area 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 provides output shaft higher torque and lower rpm.
Planetary gearboxes generally have solitary or two-equipment 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 number 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 initial consider the precision needed in the application form. If backlash and positioning accuracy are necessary, 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 that 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. In fact, 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 keep advantages because stacking phases is unnecessary, therefore the gearbox could be shorter and less expensive.
Finally, consider size. Many manufacturers offer square-framed planetary gearboxes that mate precisely 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 then to greater than 100:1, respectively.
Conversely, cycloidal reducers are bigger in diameter for the same torque but 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 selecting the most appropriate gearbox also consists of bearing capability, 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 provide engineers with a stability 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 any industry that uses servos or stepper motors. And although both are epicyclical reducers, the Cycloidal gearbox distinctions between many planetary gearboxes stem more from gear geometry and manufacturing procedures instead of principles of operation. But cycloidal reducers are more diverse and share small in common with one another. There are advantages in each and engineers should think about the strengths and weaknesses when selecting one over the various 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
Great things about 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 concise size
• Quiet operation
The need for gearboxes
There are three basic reasons to employ a gearbox:
Inertia matching. The most typical reason for choosing the gearbox is to control inertia in highly dynamic situations. Servomotors can only just control up to 10 times their personal inertia. But if response time is critical, the engine should control significantly less than four moments its own inertia.
Speed reduction, Servomotors operate more efficiently at higher speeds. Gearboxes help 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 utilize 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 inner pins, keeping the reduction high and the rotational inertia low. The wheel incorporates a curved tooth profile instead of the more traditional involute tooth profile, which removes shear forces at any stage of contact. This style introduces compression forces, rather than those shear forces that could can be found with an involute equipment mesh. That provides a number of performance benefits such as high shock load capacity (>500% of rating), minimal friction and use, lower mechanical service elements, among many others. The cycloidal style also has a large output shaft bearing span, which gives 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 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 as all get-out
The entire EP design proves to be extremely durable, and it needs minimal maintenance following installation. The EP is the most reliable reducer in the industrial marketplace, in fact it is a perfect suit for applications in weighty industry such as for example oil & gas, primary and secondary steel processing, industrial food production, metal trimming and forming machinery, wastewater treatment, extrusion devices, among others.