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 an eye on the cycloidal cam lobes engages cam supporters in the casing. Cylindrical cam followers act as teeth on the inner gear, and the number of cam followers exceeds the amount of cam lobes. The next track of compound 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 increasing torque and reducing quickness.
Compound cycloidal gearboxes provide ratios ranging from only 10:1 to 300:1 without stacking phases, as in regular planetary gearboxes. The gearbox’s compound reduction and may be calculated using:
where nhsg = the amount 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 many commercial variations of cycloidal reducers. And unlike planetary gearboxes where variations are based on gear geometry, heat therapy, and finishing procedures, cycloidal variations share simple design principles but generate cycloidal motion in different ways.
Planetary gearboxes are made up of three simple force-transmitting elements: a sun gear, three or more satellite or planet gears, and an internal ring gear. In an average gearbox, the sun equipment attaches to the insight shaft, which is connected to the servomotor. The sun gear transmits engine rotation to the satellites which, subsequently, rotate in the stationary ring gear. The ring equipment is portion of the gearbox housing. Satellite gears rotate on rigid shafts linked to the earth carrier and cause the earth carrier to rotate and, thus, turn the output shaft. The gearbox gives the output shaft higher torque and lower rpm.
Planetary gearboxes generally have single or two-equipment stages for reduction ratios which range 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 next formula:where nring = the number 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 offer the best choice. Removing backlash can also help the servomotor handle high-cycle, high-frequency moves.
Next, consider the ratio. Engineers can do this by optimizing the reflected load/gearbox Cycloidal gearbox inertia and acceleration for the servomotor. In ratios from 3:1 to 100:1, planetary gearboxes provide best torque density, weight, and precision. Actually, 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 required ratio goes beyond 100:1, cycloidal gearboxes keep advantages because stacking stages 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 solitary 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 greater than 100:1, respectively.
Conversely, cycloidal reducers are bigger in diameter for the same torque but are not as long. The compound decrease cycloidal gear train handles all ratios within the same package deal size, so higher-ratio cycloidal gear 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 requires 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 perform properly and provide engineers with a balance of performance, existence, and worth, sizing and selection should 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 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 instead of principles of procedure. But cycloidal reducers are more diverse and share little in common with one another. There are advantages in each and engineers should consider the strengths and weaknesses when selecting one over the various 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
Great things about cycloidal gearboxes
• Zero or very-low backlash stays relatively constant during life 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 necessity for gearboxes
There are three basic reasons to use 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 electric motor should control less than four situations its own inertia.
Speed reduction, Servomotors operate more efficiently in higher speeds. Gearboxes help to keep motors working at their optimal speeds.
Torque magnification. Gearboxes provide mechanical advantage by not merely decreasing swiftness but also increasing result 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 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 removes shear forces at any point 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 overall performance benefits such as for example high shock load capability (>500% of rating), minimal friction and put on, lower mechanical service elements, among numerous 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;
Capable of handling 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 engine 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 industrial marketplace, in fact it is a perfect fit for applications in heavy industry such as for example oil & gas, primary and secondary metal processing, industrial food production, metal slicing and forming machinery, wastewater treatment, extrusion devices, among others.