Ever-Power new planetary reducers employ a floating sun equipment rather than a set position one.
The word ”There’s nothing new under the sun’ certainly applies to planetary reducers. And, while floating sun gears have already been around quite a while, some engineers might not end up being aware of the benefits this unusual gear design can offer.
Traditionally, planetary reducers have used a set sun gear, where in fact the centre gear is mounted on or machined in to the shaft. When this set sun gear revolves, it turns the planet gears to create movement and/or power. Ever-Power new planetary reducers, however, are having a floating sun gear rather than a fixed position sun gear.
Why a floating sunlight equipment? ‘In the planetary idea, the sun is the driver, or pinion, in the apparatus set,’Ever-Power style engineer Scott Hulstein said. ‘Because the sun gear is in continuous contact with the planets, it’s important that it’s properly centred among the three planets to be able to provide equal load posting among itself and all three planets.’
Because of normal manufacturing tolerances nevertheless, a sun equipment which is securely fixed on a shaft will intermittently have significantly more load on one planet gear than on another equipment Hulstein explained. ‘By allowing the sun equipment to float, it centres itself among the three planets and produces continuous, equal load sharing.’
Equal load posting is merely one of the advantages of this design. The floating sun gear provides ‘accurate involute sun planet gear actions,’ according to Hulstein. True involute action takes place when the rolling motion between the mating gears is as complete as possible. The advantage of this finish meshing of gears is longer reducer life, since less internal gear slippage means fewer damaged gear teeth.
That also means lower noise levels. When the sun gear is permitted to completely roll into the planet gears, there’s much less ‘rattling’ as the teeth mesh. In place, the Ever-Power product provides ‘designed out’ the apparatus mesh sound by allowing sunlight equipment to float into place.
So why make use of a set sun gear at almost all? ‘Fixed sun gears tend to be used in accurate servo applications,’ Greg Pennings, Ever-Power Consumer Advocate, explained. ‘A set sun gear is essential when specific positioning and low backlash are an integral part of the app.’ Ever-Power engineers, however, were less concerned with low backlash and more interested with higher torque and/or lower noise applications.
Our planetary reducers with floating sunlight gears were designed to compete with parallel shaft reducers, where backlash was less critical,’ Pennings said.
Utilizing the floating sun gear concept, the Ever-Power planetary reducers can exceed the torque rankings of similar sized and bigger sized parallel shaft reducers, yet maintain a lower noise levels.
Sun, Ring and Planet
The most basic kind of planetary gearset is demonstrated in the figures above. The figure at remaining shows a three-dimensional watch as the figure at correct offers a cross-section. In this geartrain, inputs and result can be taken from the carrier, band and sunlight gears, and just the planet experiences epicyclic motion. This is the the majority of common kind of planetary gearset (with the exception of the differential) and it discovers application in rate reducers and automated transmissions. Invest the apart a cordless drill, you’ll probably find this type of planetary gearset directly behind the drill chuck.
Two Suns – Two Planets gearset
Cross-sectional view
Two Suns, Two Planets
The gearset proven above has two sunlight gears, and the two planet gears (the yellow gears) rotate as an individual unit. Sunlight gears (green and brownish) can rotate independently of 1 another. The inputs and result can be selected from either sun gear and/or the carrier. Very high speed reductions can be achieved with this unit, but it can suffer from low efficiency if not designed correctly.
Crimson sun input – purple sun fixed
Purple sun input – red sun fixed
The animations above show the ‘two suns – two planets’ gearset with one sunlight as input and the other sunlight fixed. Remember that the carrier rotates clockwise in the animation at left and counterclockwise in the animation at right – despite the fact that sunlight rotates counterclockwise in both situations.
The Differential
The gearset proven above is different from the preceding gearsets in that it is composed of miter gears instead of spur (or helical) gears. The ‘sun’ gears are those that do not undergo the epicyclic motion experienced by the earth. And the differential can be used to measure the difference in speed between two shafts for the purpose of synchronization. In addition, the differential is frequently used in auto drive trains to overcome the difference in wheel quickness when a car goes around a corner.