Cycloidal gearboxes or reducers contain four basic components: a high-speed input shaft, a single 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 substance reducers, the first an eye on the cycloidal cam lobes engages cam followers in the casing. Cylindrical cam followers become teeth on the internal gear, and the amount of cam fans exceeds the number of cam lobes. The next track of compound cam lobes engages with cam followers on the output shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus raising torque and reducing swiftness.
Compound cycloidal gearboxes provide Cycloidal gearbox ratios ranging from only 10:1 to 300:1 without stacking levels, as in regular planetary gearboxes. The gearbox’s compound reduction and can 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 swiftness output shaft (flange).
There are many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat treatment, and finishing processes, cycloidal variations share fundamental design principles but generate cycloidal motion in different ways.
Planetary gearboxes are made up of three fundamental 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 gear attaches to the insight shaft, which is linked to the servomotor. The sun gear transmits electric motor rotation to the satellites which, in turn, rotate in the stationary ring equipment. The ring gear is portion of the gearbox housing. Satellite gears rotate on rigid shafts connected to the planet carrier and cause the earth carrier to rotate and, thus, turn the output shaft. The gearbox provides result 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 can 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 number of teeth in the internal 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 precision are necessary, then cycloidal gearboxes provide best choice. Removing backlash can also help the servomotor manage 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 best torque density, weight, and precision. Actually, not many cycloidal reducers provide ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers can be used. However, 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 offer square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes grow in length from solitary 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 larger in diameter for the same torque yet are not for as long. The compound decrease 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 a preliminary gearbox selection. But deciding on the best gearbox also entails bearing capability, torsional stiffness, shock loads, environmental conditions, duty cycle, and life.
From a mechanical perspective, gearboxes have grown to be somewhat of accessories to servomotors. For gearboxes to execute properly and offer engineers with a stability of performance, lifestyle, and value, sizing and selection should 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 distinctions between many planetary gearboxes stem more from equipment geometry and manufacturing procedures rather than 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 choosing 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
Great things about cycloidal gearboxes
• Zero or very-low backlash remains relatively constant during existence 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 employ a gearbox:
Inertia matching. The most common 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 period is critical, the engine should control less than four moments its own inertia.
Speed reduction, Servomotors operate more efficiently in higher speeds. Gearboxes help to keep motors operating at their ideal speeds.
Torque magnification. Gearboxes offer mechanical advantage by not only decreasing velocity 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 comprised of an eccentric roller bearing that drives a wheel around a couple of inner 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 gets rid of 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 efficiency benefits such as for example high shock load capacity (>500% of rating), minimal friction and wear, lower mechanical service elements, among many 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;
Able to handle 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 may be the most dependable reducer in the commercial marketplace, and it is a perfect suit for applications in large industry such as for example oil & gas, major and secondary steel processing, commercial food production, metal trimming and forming machinery, wastewater treatment, extrusion equipment, among others.