sun planet gear

Ever-Power new planetary reducers employ a floating sun gear rather than a set position one.
The word ”There’s nothing new under the sun’ certainly pertains to planetary reducers. And, while floating sun gears have been around quite a while, some engineers may not become aware of the huge benefits this unusual gear design can offer.
Traditionally, planetary reducers have used a set sun gear, where in fact the centre gear is attached to or machined in to the shaft. When this fixed sun gear revolves, it turns the earth gears to create movement and/or power. Ever-Power new planetary reducers, however, are employing a floating sun equipment rather than a set position sun gear.
Why a floating sunlight equipment? ‘In the planetary concept, the sun may be the driver, or pinion, in the gear set,’Ever-Power style engineer Scott Hulstein said. ‘Because sunlight gear is in constant connection 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.’
Due to normal manufacturing tolerances however, a sun equipment which is securely set upon a shaft will intermittently have more load on one planet gear than on another equipment Hulstein explained. ‘By enabling the sun equipment to float, it centres itself among the three planets and creates constant, equal load sharing.’
Equal load sharing is just one of the advantages of this design. The floating sunlight gear provides ‘accurate involute actions,’ according to Hulstein. Accurate involute action happens when the rolling motion between your mating gears is really as complete as possible. The benefit of this finish meshing of gears is definitely longer reducer existence, 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 world gears, there’s much less ‘rattling’ as one’s teeth mesh. In place, the Ever-Power product provides ‘designed out’ the apparatus mesh sound by allowing the sun gear to float into place.
So why make use of a fixed sun gear at almost all? ‘Fixed sun gears tend to be used in true servo applications,’ Greg Pennings, Ever-Power Consumer Advocate, explained. ‘A fixed sun gear is essential when specific positioning and low backlash are an intrinsic part of the program.’ 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 compete with parallel shaft reducers, where backlash was less critical,’ Pennings said.
By using the floating sun gear concept, the Ever-Power planetary reducers can exceed the torque rankings of similar sized and bigger sized parallel shaft reducers, and yet maintain a lower noise levels.
Sun, Ring and Planet
The most basic type of planetary gearset is proven in the figures above. The figure at remaining shows a three-dimensional view while the figure at correct provides a cross-section. In this geartrain, inputs and output can be extracted from the carrier, ring and sunlight gears, and just the earth experiences epicyclic motion. That is the many common kind of planetary gearset (apart from the differential) and it discovers application in velocity reducers and automated 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 sunlight gears, and the two planet gears (the yellow gears) rotate as a single unit. The sun gears (green and dark brown) can rotate independently of one another. The inputs and output can be chosen from either sun gear and/or the carrier. Very high speed reductions may be accomplished with this unit, nonetheless it can have problems with low efficiency if not designed correctly.
Crimson sun input – purple sun fixed
Purple sun input – reddish 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 computer animation at remaining 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 in that it is made up of miter gears instead of spur (or helical) gears. The ‘sun’ gears are those that do not go through the epicyclic motion experienced by the earth. And the sun planet gear differential can be utilized to measure the difference in rate between two shafts for the intended purpose of synchronization. Furthermore, the differential is frequently used in auto drive trains to overcome the difference in wheel acceleration when a car encircles a corner.