Cycloidal gearboxes or reducers consist of four simple components: a high-speed input shaft, a single or substance 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 track of the cycloidal cam lobes engages cam followers in the casing. Cylindrical cam followers act as 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 supporters on the result shaft and transforms the cam’s eccentric rotation into concentric rotation of the output shaft, thus raising torque and reducing acceleration.
Compound cycloidal gearboxes provide Cycloidal gearbox ratios ranging from only 10:1 to 300:1 without stacking levels, as in standard planetary gearboxes. The gearbox’s compound decrease and can be calculated using:
where nhsg = the number of followers or rollers in the fixed housing and nops = the quantity for followers or rollers in the gradual acceleration output shaft (flange).
There are several 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 movement in different ways.
Planetary gearboxes are made up of three simple force-transmitting elements: a sun gear, three or even more satellite or world gears, and an internal ring gear. In a typical gearbox, the sun gear attaches to the input shaft, which is linked to the servomotor. Sunlight gear transmits electric motor rotation to the satellites which, subsequently, rotate inside the stationary ring gear. The ring equipment is part of the gearbox housing. Satellite gears rotate on rigid shafts linked to the earth carrier and cause 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 one or two-equipment stages for reduction ratios ranging from 3:1 to 100:1. A third stage can be added for actually higher ratios, but it is not common.
The ratio of a planetary gearbox is calculated using the following formula:where nring = the amount of teeth in the internal 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 1st consider the precision needed in the application form. If backlash and positioning precision are crucial, then cycloidal gearboxes provide most suitable choice. Removing backlash may also help the servomotor deal with high-cycle, high-frequency moves.
Next, consider the ratio. Engineers can do this by optimizing the reflected load/gearbox inertia and quickness for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes provide greatest torque density, weight, and precision. In fact, 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. The majority of manufacturers provide square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes grow in length from single to two and three-stage designs as needed gear ratios go from less than 10:1 to between 11:1 and 100:1, and then to higher than 100:1, respectively.
Conversely, cycloidal reducers are bigger in diameter for the same torque yet are not for as long. The compound reduction cycloidal gear train handles all ratios within the same package size, therefore higher-ratio cycloidal equipment boxes become actually 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 consists of 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 perform properly and provide engineers with a stability of performance, lifestyle, and value, sizing and selection ought to be determined from the load side back again to the motor as opposed to the motor out.
Both cycloidal and planetary reducers are appropriate in virtually any industry that uses servos or stepper motors. And although both are epicyclical reducers, the distinctions between the majority of planetary gearboxes stem more from equipment geometry and manufacturing procedures rather than principles of procedure. But cycloidal reducers are more different and share little in common with one another. There are advantages in each and engineers should consider the strengths and weaknesses when choosing one over the various 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 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 compact size
• Quiet operation
The necessity for gearboxes
There are three basic reasons to employ a gearbox:
Inertia matching. The most common reason for selecting a gearbox is to control inertia in highly powerful circumstances. Servomotors can only just control up to 10 times their very own inertia. But if response period is critical, the engine should control significantly less than four moments 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 offer mechanical advantage by not merely decreasing speed 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 main power train is made up 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 rather than 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 exist with an involute gear mesh. That provides numerous functionality benefits such as high shock load capability (>500% of rating), minimal friction and use, lower mechanical service factors, among numerous others. The cycloidal style also has a huge output shaft bearing period, which gives exceptional overhung load capabilities without requiring any additional expensive components.
Cycloidal advantages over other styles of gearing;
Capable of handling 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 since all get-out
The overall EP design proves to be extremely durable, and it requires minimal maintenance following installation. The EP is the most reliable reducer in the commercial marketplace, and it is a perfect match for applications in heavy industry such as oil & gas, major and secondary metal processing, commercial food production, metal cutting and forming machinery, wastewater treatment, extrusion equipment, among others.