November 7, 2019

Ever-Power new planetary reducers hire a floating sun gear rather than a fixed position one.
The saying ”There’s nothing new under the sun’ certainly applies to planetary reducers. And, while floating sun gears have already been around a long time, some engineers may not be aware of the benefits this unusual gear design can offer.
Traditionally, planetary reducers have used a fixed sun gear, where in fact the centre gear is attached to or machined into the shaft. When this set sun equipment 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 set position sun gear.
Why a floating sun equipment? ‘In the planetary idea, the sun is the driver, or pinion, in the gear set,’Ever-Power design engineer Scott Hulstein said. ‘Because the sun gear is in constant connection with the planets, it’s important that it is 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 however, a sun gear which is securely set upon a shaft will intermittently have significantly more load on one planet equipment than on another equipment Hulstein explained. ‘By enabling the sun gear to float, it centres itself among the three planets and generates continuous, equal load sharing.’
Equal load posting is merely one of the benefits of this design. The floating sun gear provides ‘true involute action,’ according to Hulstein. Accurate involute action occurs when the rolling motion between the mating gears is really as complete as possible. The benefit of this total meshing of gears is definitely longer reducer existence, since less internal gear slippage means fewer damaged gear teeth.
That also means lower noise amounts. When sunlight gear is allowed to completely roll into the world gears, there’s less ‘rattling’ as the teeth mesh. In place, the Ever-Power product provides ‘designed out’ the gear mesh sound by allowing the sun gear to float into place.
So why make use of a set sun gear at every? ‘Fixed sun gears are often used in true servo applications,’ Greg Pennings, Ever-Power Client Advocate, explained. ‘A fixed sun gear is necessary when specific positioning and low backlash are an integral part of the software.’ Ever-Power engineers, however, were less worried about low backlash and more interested with higher torque and/or lower sound applications.
Our planetary reducers with floating sun gears were made to contend with parallel shaft reducers, where backlash was less critical,’ Pennings said.
Utilizing the floating sun equipment concept, the Ever-Power planetary reducers can easily exceed the torque ratings of similar sized and bigger sized parallel shaft reducers, and yet maintain a lesser noise levels.
Sun, Ring and Planet
The most basic kind of planetary gearset is demonstrated in the figures above. The figure at left shows a three-dimensional watch as the figure at correct offers a cross-section. In this geartrain, inputs and output can be taken from the carrier, band and sunlight gears, and just the earth experiences epicyclic motion. That is the many common type of planetary gearset (with the exception of the differential) and it discovers application in speed reducers and automatic transmissions. If you take aside a cordless drill, you will most probably find this kind of planetary gearset directly behind the drill chuck.
Two Suns – Two Planets gearset
Cross-sectional view
Two Suns, Two Planets
The gearset shown above has two sun gears, and the two planet gears (the yellow gears) rotate as an individual unit. Sunlight gears (green and dark brown) can rotate independently of one another. The inputs and result can be chosen from either sun equipment and/or the carrier. High speed reductions may be accomplished with this unit, nonetheless 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 sun as input and the other sunlight fixed. Note that the carrier rotates clockwise in the computer animation at left and counterclockwise in the computer 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 for the reason 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 planet. And the sun planet gear differential can be utilized to gauge 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 velocity when a car encircles a corner.