sun planet gear

Ever-Power new planetary reducers employ a floating sun equipment rather than a fixed position one.
The saying ”There’s nothing new under the sun’ certainly applies to planetary reducers. And, while floating sunlight gears have already been around a long time, some engineers may not end up being aware of the benefits this unusual gear design can offer.
Traditionally, planetary reducers possess used a fixed sun gear, where the centre gear is sun planet gear mounted on or machined in to the shaft. When this set 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 gear rather than a set position sun gear.
Why a floating sunlight gear? ‘In the planetary idea, the sun may be the driver, or pinion, in the apparatus set,’Ever-Power design engineer Scott Hulstein stated. ‘Because the sun gear is in constant contact with the planets, it’s important that it’s perfectly centred among the three planets in order 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 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 sharing is just one of the benefits of this design. The floating sunlight gear provides ‘accurate involute action,’ according to Hulstein. True involute action happens when the rolling motion between the mating gears is really as complete as feasible. The advantage of this complete meshing of gears is longer reducer existence, since less internal equipment slippage means fewer damaged gear teeth.
That also means lower noise amounts. When the sun gear is permitted to completely roll into the planet gears, there’s much less ‘rattling’ as one’s teeth mesh. In place, the Ever-Power product offers ‘designed out’ the gear mesh noise by allowing the sun gear to float into place.
So why use a set sun gear at all? ‘Fixed sun gears tend to be used in true servo applications,’ Greg Pennings, Ever-Power Consumer Advocate, explained. ‘A fixed sun gear is necessary when exact positioning and low backlash are an integral part of the program.’ Ever-Power engineers, however, were less worried about low backlash and more interested with higher torque and/or lower noise applications.
Our planetary reducers with floating sun gears were designed 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 can exceed the torque rankings of similar sized and larger sized parallel shaft reducers, and 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 still left shows a three-dimensional view while the figure at correct provides a cross-section. In this geartrain, inputs and result can be taken from the carrier, band and sun gears, and only the planet experiences epicyclic motion. That is the the majority of common kind of planetary gearset (with the exception of the differential) and it discovers application in quickness reducers and automated transmissions. If you take apart a cordless drill, you’ll 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 brownish) can rotate independently of 1 another. The inputs and output can be selected from either sun equipment and/or the carrier. Very high speed reductions may be accomplished with this unit, nonetheless it can have problems with low efficiency if not really designed correctly.
Reddish 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 animation at remaining and counterclockwise in the computer animation at right – even though the sun rotates counterclockwise in both situations.
The Differential
The gearset shown above is different from the preceding gearsets for the reason that it is composed of miter gears rather than spur (or helical) gears. The ‘sun’ gears are the ones that do not undergo the epicyclic movement experienced by the earth. And the differential can be utilized to measure the difference in acceleration between two shafts for the intended purpose of synchronization. In addition, the differential is frequently used in automotive drive trains to overcome the difference in wheel acceleration when a car goes around a corner.