sun planet gear

Ever-Power new planetary reducers hire a floating sun gear rather than a set position one.
The word ”There’s nothing new under the sun’ certainly applies to planetary reducers. And, while floating sun gears have already been around quite a while, some engineers might not end up being aware of the huge benefits this unusual gear style can offer.
Traditionally, planetary reducers have used a set sun gear, where the centre gear is mounted on or machined into the shaft. When this set sun equipment 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 fixed position sun gear.
Why a floating sunlight equipment? ‘In the planetary idea, the sun is the driver, or pinion, in the apparatus set,’Ever-Power style engineer Scott Hulstein stated. ‘Because the sun gear is in continuous connection with the planets, it’s important that it’s perfectly centred among the three planets to be able to provide equal load sharing among itself and all three planets.’
Due to normal manufacturing tolerances nevertheless, a sun gear which is securely set on a shaft will intermittently have significantly more load on one planet equipment than on another equipment Hulstein explained. ‘By permitting the sun gear to float, it centres itself among the three planets and creates constant, equal load sharing.’
Equal load posting is just one of the benefits of this design. The floating sun gear provides ‘accurate sun planet gear involute actions,’ according to Hulstein. Accurate involute action occurs when the rolling motion between your mating gears is really as complete as feasible. The benefit of this full meshing of gears is certainly longer reducer life, since less internal equipment slippage means fewer broken gear teeth.
That also means lower noise amounts. When the sun gear is allowed 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 apparatus mesh sound by allowing sunlight gear to float into place.
So why use a set sun gear at almost all? ‘Fixed sun gears tend to be used in accurate servo applications,’ Greg Pennings, Ever-Power Customer Advocate, explained. ‘A set sun gear is essential when precise positioning and low backlash are an intrinsic part of the app.’ Ever-Power engineers, however, were less concerned with 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.
By using the floating sun equipment concept, the Ever-Power planetary reducers have the ability to 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 still left shows a three-dimensional view as the figure at right provides 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. That is the most common kind of planetary gearset (with the exception of the differential) and it discovers application in speed reducers and automated transmissions. If you take aside 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 proven above has two sunlight gears, and the two planet gears (the yellow gears) rotate as a single unit. The sun gears (green and brownish) can rotate independently of one another. The inputs and result can be selected from either sun gear and/or the carrier. High speed reductions may be accomplished with this unit, nonetheless it can suffer from low efficiency if not designed correctly.
Reddish 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 sun fixed. Remember that the carrier rotates clockwise in the computer animation at left and counterclockwise in the animation at right – even though the sun rotates counterclockwise in both cases.
The Differential
The gearset demonstrated above differs from the preceding gearsets in that it is composed of miter gears instead of 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 used to gauge the difference in rate between two shafts for the purpose of synchronization. In addition, the differential is frequently used in automotive drive trains to conquer the difference in wheel velocity when a car encircles a corner.