Cycloidal gearboxes or reducers contain four basic components: a high-speed input shaft, an individual or compound cycloidal cam, cam Cycloidal gearbox 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 tabs on the cycloidal cam lobes engages cam supporters in the housing. Cylindrical cam followers act as teeth on the inner gear, and the amount of cam supporters exceeds the number of cam lobes. The second track of substance cam lobes engages with cam supporters on the output 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 as low as 10:1 to 300:1 without stacking phases, as in standard planetary gearboxes. The gearbox’s compound reduction and may 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 are based on gear geometry, heat therapy, 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 an average gearbox, the sun equipment attaches to the input shaft, which is linked to the servomotor. Sunlight gear transmits engine rotation to the satellites which, in turn, rotate inside the stationary ring gear. The ring equipment is portion 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 solitary or two-gear stages for reduction ratios which range from 3:1 to 100:1. A third stage could be added for even higher ratios, nonetheless it is not common.
The ratio of a planetary gearbox is calculated using the next formula:where nring = the number of teeth in the inner ring gear and nsun = the number of teeth in the pinion (input) gear.
Comparing the two
When deciding among 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 best choice. Removing backlash may also help the servomotor handle high-cycle, high-frequency moves.
Following, consider the ratio. Engineers can do that by optimizing the reflected load/gearbox inertia and velocity for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes offer the best torque density, weight, and precision. Actually, few cycloidal reducers offer ratios below 30:1. In ratios from 11:1 to 100:1, planetary or cycloidal reducers may be used. Nevertheless, if the required ratio goes beyond 100:1, cycloidal gearboxes hold advantages because stacking phases is unnecessary, so the gearbox could be shorter and less expensive.
Finally, consider size. The majority of manufacturers provide square-framed planetary gearboxes that mate specifically with servomotors. But planetary gearboxes develop in length from single to two and three-stage styles as needed gear ratios go from significantly less than 10:1 to between 11:1 and 100:1, and to higher 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 train handles all ratios within the same deal size, therefore 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 requires bearing capacity, 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, lifestyle, and worth, sizing and selection ought to be determined from the strain 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 equipment geometry and manufacturing processes rather than principles of operation. 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.
Great things about planetary gearboxes
• High torque density
• Load distribution and sharing 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 life 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 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 powerful circumstances. Servomotors can only just control up to 10 times their own inertia. But if response time is critical, the electric motor should control less than four moments its own inertia.
Speed reduction, Servomotors operate more efficiently at higher speeds. Gearboxes help to keep motors working at their optimal 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 make use of 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 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 gets rid of shear forces at any point of contact. This style introduces compression forces, rather than those shear forces that would can be found with an involute gear mesh. That provides several overall performance benefits such as high shock load capability (>500% of rating), minimal friction and put on, lower mechanical service factors, among many others. The cycloidal style also has a sizable 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 compact dimensional footprint
Exceptional “built-in” overhung load carrying capability
High efficiency (>95%) per reduction stage
Minimal reflected inertia to motor 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 dependable reducer in the industrial marketplace, and it is a perfect fit for applications in weighty industry such as for example oil & gas, principal and secondary steel processing, commercial food production, metal reducing and forming machinery, wastewater treatment, extrusion apparatus, among others.