sun planet gear

Ever-Power new sun planet gear planetary reducers employ a floating sun equipment rather than a set position one.
The saying ”There’s nothing new beneath the sun’ certainly pertains to planetary reducers. And, while floating sun gears have been around quite a while, some engineers may not end up being aware of the huge benefits this unusual gear design can offer.
Traditionally, planetary reducers have used a fixed sun gear, where the centre gear is mounted on or machined in to 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 employing a floating sun equipment rather than a fixed position sun gear.
Why a floating sun equipment? ‘In the planetary concept, the sun may be the driver, or pinion, in the gear set,’Ever-Power design engineer Scott Hulstein stated. ‘Because sunlight gear is in constant connection with the planets, it’s important that it is flawlessly 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 gear which is securely fixed upon a shaft will intermittently have significantly more load using one planet gear than on another gear Hulstein explained. ‘By allowing the sun gear to float, it centres itself among the three planets and generates continuous, equal load sharing.’
Equal load posting is just one of the advantages of this design. The floating sunlight gear provides ‘accurate involute action,’ according to Hulstein. True involute action happens when the rolling motion between your mating gears is really as complete as feasible. The benefit of this complete meshing of gears is longer reducer existence, since less internal gear slippage means fewer broken gear teeth.
That also means lower noise levels. When the sun gear is allowed to completely roll in to the world gears, there’s less ‘rattling’ as one’s teeth mesh. In place, the Ever-Power product has ‘designed out’ the apparatus mesh noise by allowing sunlight gear to float into place.
So why make use of a fixed sun gear at almost all? ‘Fixed sun gears are often used in accurate servo applications,’ Greg Pennings, Ever-Power Customer Advocate, explained. ‘A set sun gear is necessary when precise positioning and low backlash are an intrinsic part of the program.’ Ever-Power engineers, nevertheless, 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 made to contend with parallel shaft reducers, where backlash was less critical,’ Pennings said.
By using the floating sun gear concept, the Ever-Power planetary reducers have the ability to exceed the torque rankings of similar sized and larger sized parallel shaft reducers, yet maintain a lesser 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 look at while the figure at right provides a cross-section. In this geartrain, inputs and output can be taken from the carrier, ring and sunlight gears, and only the planet experiences epicyclic motion. That is the most common type of planetary gearset (with the exception of the differential) and it discovers application in velocity reducers and automated transmissions. Invest the apart a cordless drill, you’ll probably find this kind of planetary gearset right 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 both planet gears (the yellow gears) rotate as a single unit. The sun gears (green and brown) can rotate independently of one another. The inputs and result can be chosen from either sun gear and/or the carrier. High speed reductions can be achieved with this unit, nonetheless it can suffer from low efficiency if not designed correctly.
Reddish colored sun input – purple sun fixed
Purple sun input – reddish sun fixed
The animations above show the ‘two suns – two planets’ gearset with one sun as input and the other sun fixed. Remember that the carrier rotates clockwise in the computer animation at still left and counterclockwise in the computer animation at right – even though sunlight rotates counterclockwise in both situations.
The Differential
The gearset shown 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 differential can be used to gauge the difference in swiftness between two shafts for the purpose of synchronization. In addition, the differential is often used in auto drive trains to conquer the difference in wheel swiftness when a car encircles a corner.


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