sun planet gear

Ever-Power new planetary reducers employ a floating sun gear rather than a fixed position one.
The word ”There’s nothing new under the sun’ certainly pertains to planetary reducers. And, while floating sunlight gears have already been around quite a while, some engineers may not be aware of the huge benefits this unusual gear style can offer.
Traditionally, planetary reducers possess used a fixed sun gear, where in fact the centre gear is mounted on or machined in to the shaft. When this fixed sun equipment revolves, it turns the earth gears to create motion and/or power. Ever-Power new planetary reducers, however, are having a floating sun equipment rather than a fixed position sun gear.
Why a floating sun gear? ‘In the planetary idea, the sun is the driver, or pinion, in the gear set,’Ever-Power design engineer Scott Hulstein stated. ‘Because the sun gear is in constant contact with the planets, it’s important that it is flawlessly centred among the three planets in order to provide equal load posting among itself and all three planets.’
Due to normal manufacturing tolerances nevertheless, a sun equipment which is securely set on a shaft will intermittently have significantly more load using one planet gear than on another equipment Hulstein explained. ‘By enabling the sun equipment to float, it centres itself among the three planets and generates constant, equal load sharing.’
Equal load sharing is merely one of the sun planet gear advantages of this design. The floating sun gear provides ‘true involute action,’ according to Hulstein. True involute action occurs when the rolling motion between your mating gears is really as complete as possible. The benefit of this finish meshing of gears can be longer reducer life, since less internal equipment slippage means fewer damaged gear teeth.
That also means lower noise levels. When the sun gear is allowed to completely roll in to the planet gears, there’s less ‘rattling’ as the teeth mesh. In effect, the Ever-Power product has ‘designed out’ the apparatus mesh noise by allowing sunlight equipment to float into place.
So why use a fixed sun gear at every? ‘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 precise positioning and low backlash are an integral part of the program.’ 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 made to contend 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 ratings of similar sized and bigger sized parallel shaft reducers, yet maintain a lesser noise levels.
Sun, Ring and Planet
The most basic type of planetary gearset is demonstrated in the figures above. The figure at still left shows a three-dimensional watch while the figure at correct offers a cross-section. In this geartrain, inputs and result can be taken from the carrier, band and sun gears, and only the earth experiences epicyclic motion. This is the many common type of planetary gearset (apart from the differential) and it finds application in acceleration reducers and automated transmissions. Invest the apart a cordless drill, you will most 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 shown above has two sun gears, and the two planet gears (the yellow gears) rotate as a single unit. Sunlight gears (green and dark brown) can rotate independently of one another. The inputs and output can be selected from either sun equipment and/or the carrier. High speed reductions can be achieved with this unit, but it can have problems with low efficiency if not designed correctly.
Reddish sun input – purple sun fixed
Purple sun input – reddish colored 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 left and counterclockwise in the animation at right – even though sunlight rotates counterclockwise in both situations.
The Differential
The gearset demonstrated above differs from the preceding gearsets for the reason that it is made up of miter gears rather than 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 utilized to measure the difference in quickness between two shafts for the purpose of synchronization. In addition, the differential is frequently used in automotive drive trains to overcome the difference in wheel velocity when a car encircles a corner.