US20110053730A1 - Epicyclic Gear System Having Two Arrays Of Pinions Mounted On Flexpins With Compensation For Carrier Distortion - Google Patents
Epicyclic Gear System Having Two Arrays Of Pinions Mounted On Flexpins With Compensation For Carrier Distortion Download PDFInfo
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- US20110053730A1 US20110053730A1 US12/866,499 US86649909A US2011053730A1 US 20110053730 A1 US20110053730 A1 US 20110053730A1 US 86649909 A US86649909 A US 86649909A US 2011053730 A1 US2011053730 A1 US 2011053730A1
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- flexpins
- pinions
- carrier
- gear system
- array
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/08—General details of gearing of gearings with members having orbital motion
- F16H57/082—Planet carriers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
- F16H1/2809—Toothed gearings for conveying rotary motion with gears having orbital motion with means for equalising the distribution of load on the planet-wheels
- F16H1/2836—Toothed gearings for conveying rotary motion with gears having orbital motion with means for equalising the distribution of load on the planet-wheels by allowing limited movement of the planets relative to the planet carrier or by using free floating planets
Abstract
An epicyclic gear system (A) includes sun and ring gears (2, 4) and planet pinions (6, 8) arranged in two side-by-side arrays (a, b) between the sun and ring gears, there also being a carrier (10, 50) to which planet pinions are coupled through flexpins (30). The carrier has primary and secondary walls (20, 22) between which the pinions are located and webs (24) connecting the walls. The flexpins for one array of pinions are cantilevered from the primary wall and the flexpins for the other array of pinions are cantilevered from the secondary wall. When the gear system operates, the carrier along its primary wall is subjected to an externally applied torque which transfers through the system at the planet pinions of the two arrays. The load path (pa) for the pinions at the primary wall is shorter than the load path (pb) for the pinions at the secondary wall, and this disparity causes the carrier to distort. To compensate for this distortion so that the pinions of the two arrays will mesh more evenly with the sun and ring gears, the flexpins of the first array are offset angularly with respect to the flexpins of the second array, or the teeth of the pinions in the first array are narrower than the teeth of the pinions of the second array, or the primary wall of the carrier has areas (40, 44) of weakness where the flexpins of the first array are cantilevered from it, or the flexpins of the first array are more flexible than the flexpins of the second array. As a consequence, the pinions of the two arrays mesh better under load with the sun and ring gears and share the transfer of torque more evenly.
Description
- This application derives priority from and otherwise claims the benefit of U.S. provisional application 61/028,274, filed 13 Feb. 2008, and U.S. provisional application 61/125,715, filed 28 Apr. 2008, both of which are incorporated herein by reference.
- This invention relates in general to epicyclic gear systems, and more particularly to an epicyclic gear system having its planet pinions arranged in two arrays on flexpins with compensation for carrier distortion.
- The typical epicyclic gear system has a sun gear, a ring gear surrounding the sun gear, and planet pinions located between and engaged with the sun and ring gears, and in addition, it has a straddle-type carrier that provides pins about which the planet pinions rotate, with the pins being anchored at both ends in the carrier. A gear system so configured has the capacity to transfer a large amount of power in a relatively compact configuration—or in other words, it has a high power density.
- But heavy loads tend to distort the carrier and its pins and skew the axis about which the planet pinions rotate. Under such conditions, the planet pinions do not mesh properly with the sun and ring gears. This causes excessive wear in the planet pinions and the sun and ring gears, generates friction and heat, and renders the entire system overly noisy.
- A planetary system in which the planet pinions are supported on and rotate about so-called flexpins mitigates the skewing. In this regard, a flexpin for a planet pinion at one end is anchored in and cantilevered from the wall of a carrier of which it is a part. The other end of the flexpin has a sleeve fitted to it, with the sleeve extending back over, yet otherwise spaced from the flexpin. The sleeve supports the planet pinion, in that it serves as a component of a bearing for the pinion. In other words, flexpin technology employs a double cantilever to offset the skewing that would otherwise occur. See U.S. Pat. No. 6,994,651 and U.S. Pat. No. 7,056,259, which are incorporated herein by reference, for a further discussion of flexpin technology.
- The cantilevers produce high stresses in the flexpins, and to have more moderate stresses, some carriers have two walls with flexpins anchored in each of the walls and, of course, a separate planetary pinion around each flexpin. This doubles the number of flexpins to share the torque transferred through the system and thus reduces the unit load applied to each flexpin. The planet pinions are arranged in two arrays between the walls, there being for each pinion in the one array and corresponding pinion aligned with it in the other array. Spaces exist between pairs of corresponding pinions and webs extend between the two walls in these spaces. The carrier, whether it rotates or not, is subjected to an externally applied torque at one of its walls. The planet pinions transmit torque through the system, but the lengths of the load paths from the flexpins on the two walls differ, the load paths from the flexpins on the primary wall, which is subjected to the external torque, being considerably shorter than the load paths from the flexpins on the other or secondary wall. This renders the array, identified with the shorter load paths stiffer than the array identified with the longer load paths. The carrier undergoes a distortion that causes the flexpins on the secondary wall displace angularly with respect to the flexpins on the primary wall, reference being to the axis of the planetary system. Since the planet pinions of the two arrays mesh with the sun and ring gears, the displacement causes an uneven sharing of the torque transmitted at the teeth where the pinions mesh with the sun and ring gears.
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FIG. 1 is a perspective view, partially broken away and in section, of an epicyclic gear system having its planet pinions arranged in two arrays on flexpins and otherwise being constructed in accordance with and embodying the present invention; -
FIG. 2 is another perspective view of the gear system, again partially broken away and in section; -
FIG. 3 is a partial sectional view showing one of the carrier walls and a flexpin on that wall; -
FIG. 4 is an exploded perspective view of a flexpin, its sleeve, bearing and planet pinion, for either one of the arrays; -
FIG. 5 is an elevational view of the carrier of the gear system, and showing load paths of uneven lengths and distortions, greatly exaggerated, caused by those uneven load paths; -
FIGS. 6 , 6A, and 6B are schematic views showing an angular offset between the flexpins of the two arrays to compensate for the distortion of the carrier and the resulting planet pinion and ring gear mesh; -
FIG. 7 is a perspective view of the carrier and also showing the angular offset; -
FIGS. 8 , 8A, and 8B are schematic views showing narrower teeth for the pinions of one of the arrays to compensate for the distortion of the carrier; and -
FIG. 9 is a perspective view of a carrier provided with areas of weakness in its primary wall to impart equivalent deflective characteristics to the flexpins of its two arrays; -
FIG. 10 is a perspective view of an alternative carrier with areas of weakness in its primary wall; -
FIG. 11 is a perspective view of a carrier that has the flexpins of differing flexibility to impart equivalent deflective characteristics; -
FIG. 12 is a longitudinal sectional view of the flexpins for the alternative carrier ofFIG. 11 ; and -
FIG. 13 is an elevational view of the carrier having a hub for transferring torque to it. - Referring now to the drawings, an epicyclic gear system A (
FIGS. 1 & 2 ) that is organized about a central axis X includes asun gear 2, aring gear 4 that surrounds thesun gear 2 and shares the axis X with thesun gear 2, andplanet pinions ring gears ring gears carrier 10 that supports theplanet pinions sun gear 2,ring gear 4, andcarrier 10 represent components, any two of which may rotate while the third is typically held fast. - The epicyclic gear system A depicted is well suited for use in wind turbines that harness the wind and convert it into electrical energy. However, it lends itself as well to other applications in which torque is applied at any one of the components and torque is delivered at either of the remaining two components, while the third component is held fast. In a wind turbine in which the epicyclic gear system A serves as the transmission for increasing the relatively low angular velocity of a wind-powered rotor to a higher velocity suitable for an electrical generator small enough to fit into the nacelle of the wind turbine, the wind-powered rotor is coupled to the
carrier 10, thesun gear 2 is connected to ashaft 12 that is coupled through more gearing to the electrical generator, and the ring gear 5 remains fixed. Thecarrier 10 andsun gear 2 rotate in the same direction. - The
carrier 10 has two walls between which the planet pinions 6 and 8 are confined—aprimary wall 20 and asecondary wall 22—and also axially directedwebs 24 that extend between thewalls webs 24 create within thecarrier 10 pockets that are occupied by theplanet pinions pinion 6 and apinion 8 in each pocket. To facilitate installation of theplanet pinions carrier 10, thewebs 24 are formed integral with thesecondary wall 22 and initially separate from theprimary wall 20, only to be secured to theprimary wall 20 withscrews 26 during assembly. Likewise, thewebs 24 may be formed integral with theprimary wall 20 and separate from thesecondary wall 22. Theshaft 12 for thesun gear 2 extends through one or both of thecarrier walls walls webs 24 for engagement with thesun gear 2 andring gear 4. Theprimary wall 20 has aflange 28 that projects radially outwardly beyond thewebs 24. Theflange 28 serves as a location or coupling region at which torque is applied to thecarrier 10. - The planet pinions 6 and 8 rotate about
flexpins 30 and sleeves 32 (FIGS. 3 & 4 ), the former of which project from thecarrier walls separate flexpin 30 andsleeve 32 for eachplanet pinion flexpin 30 is anchored in or otherwise secured firmly to thewall planet pinion wall sleeve 32 encircles theflexpin 30, yet is spaced outwardly from theflexpin 30, except at the end of theflexpin 30 that is remote from thewall sleeve 32 is attached firmly to itsflexpin 30 such that it is cantilevered from theflexpin 30, completing a double cantilever so to speak. Eachplanet pinion sleeve 32 for itsflexpin 30, there being a bearing 34 between thepinion sleeve 32. Thebearing 34 may take the form of an antifriction bearing in which the inner raceways are carried by the sleeve itself, or the sleeve may form part of a simple plain bearing. Theflexpin 30 between the location at which it is cantilevered from itswall sleeve 32 is cantilevered from thepin 30 may have agroove 36 that imparts greater flexibility to theflexpin 30. - During the operation of the gear system A, with torque transferring through it, the
flexpins 30 undergo flexures that offset their ends circumferentially with respect to the axis X. In other words, the remote end of each flexpin 30 lags slightly behind or advances slightly ahead of the end that are anchored in or to thecarrier wall sleeve 32, being cantilevered from the remote end of thepin 30, imparts a moment that causes the end of thepin 30 to flex in the opposite direction. Owing to this capacity of thepins 30 to flex, under two cantilevers, thesleeves 32 remain parallel to the central axis X, and, of course, the axes Y about which the planet pinions 6 and 8 rotate likewise remain parallel to the axis X. - When torque is applied to the
carrier 10 at theflange 28 on itsprimary wall 20, that torque transfers between theflange 28 and to thepinions 6 of the array a in relatively short load paths pa (FIG. 5 ) that are basically confined to theprimary wall 20 and theflexpins 30 on thatwall 20. The torque also transfers between theflange 28 and thepinions 8 of the array b in significantly longer load paths pb that pass through theprimary wall 20, thewebs 24, thesecondary wall 22, and theflexpins 30 on thatwall 22. Were the carrier 10 a traditional carrier, the torque transferred through the shorter load paths pa may cause some distortion of theprimary wall 20, but it is for all intents and purposes inconsequential. The torque transferred through the longer load paths pb would effect a much greater distortion in the more flexiblesecondary wall 22 andwebs 24. This would render the array a having the shorter load path pa stiffer than the array b having the longer load paths pb. With the axis X serving as a reference, the distortion would offset theflexpins 30 of the array b circumferentially with respect to theflexpins 30 of the array a. If under no load thepins 30 of the array a were to align with thepins 30 of the array b, once a load is applied to thecarrier 10, thereby effecting a transfer of torque, theflexpins 30 of the array b will no longer align with theflexpins 30 in the array a. The planet pinions 6 of the array a and the planet pinions 8 of the array b would not mesh evenly with thesun gear 2 andring gear 4. The uneven mesh would cause the planet pinions 6 of the array a to carry a greater load than the planet pinions 8 of the array b when the torque transferred through the system A reaches the torque at which the system A is designed to operate. - To compensate for the distortion of the
carrier 10 and thereby overcome the deficiency, thecarrier 10 is constructed such that when no torque is transmitted through it, the planet pinions 6 of the array a are indexed or offset circumferentially by an angle θ with respect to the planet pinions 8 of the array b (see arrows inFIG. 7 ). Thus, when the epicyclic gear system A is set in operation with a light torque applied at thecarrier flange 28 and delivered through theshaft 12, the planet pinions 8 of the array b will engage first with thesun gear 2 andring gear 4. As the torque increases, thecarrier 10 undergoes distortions along itssecondary wall 22 and at itswebs 24 of the less stiff array b, and those distortions bring the planet pinions 8 of the array b closer to alignment with theircounterpart pinions 6 in the array a. At the torque at which the system A is designed to operate, theflexpins 30 of the array b align with their counterparts in the array a and the planet pinions 6 and 8 mesh generally evenly with thesun gear 2 andring gear 4. The planet pinions 6 and 8 of the two arrays a and b then share the transfer of torque generally evenly. - In any gear system, a backlash or clearance exists between the teeth where two gears mesh. In the system A, a clearance lb (
FIG. 6A ) exists where anyplanet pinion 8 engages thering gear 4, that is to say, at the tooth on theplanet pinion 8 that projects between a pair of successive teeth in thering gear 4 and on thesun gear 2 as well. At no load or very light loads, the teeth of the planet pinions 6 in the array a do not actually engage the teeth of thering gear 4 in the sense that the leading faces actually contact teeth of thering gear 4, that is to say, a clearance exists on both sides of each meshed tooth. This derives from a smaller clearance la (FIG. 6B ) where the planet pinions 6 mesh with thering gear 4, and that lesser clearance la exists by reason of a slight angular offset θ of theflexpins 30 for the planet pinions 8 of the array b from theflexpins 30 of the array a, resulting in an offset clearance lθ. That offset clearance lθ should conform to the following relationship: -
l b ≧l b =l θ +l a - As the torque applied at the
carrier flange 28 increases, so does the clearance la in the array a. When the torque reaches that at which the system A is designed to operate, the clearance la in the array a and the clearance lb in the array b are substantially the same, and the planet pinions 6 and 8 mesh essentially evenly with thering gear 4. Since the mesh is even, the planet pinions 6 and 8 share the torque evenly, that is to say, the magnitude of the torque transferred through the planet pinions 6 of the array a is substantially the same as the magnitude of the torque transferred through thepinions 8 of the array b. The conditions and compensation that exists at the mesh between the planet pinions 6 and 8 and thering gear 4 also exist at the mesh between the planet pinions 6 and 8 and thesun gear 2. - While the
screws 26 hold thecarrier 10 together in that they pass through theprimary wall 20 and thread into thewebs 24 or otherwise clamp thewebs 24 and thewalls pins 30 of the array a and thepins 30 of the array b. The precision may be achieved with dowels 38 (FIG. 7 ) that fit tightly into theprimary wall 20 and into the webs 23, assuming that thesecondary walls 22 and theweb 24 are formed integral. - In the alternative, the compensation for distortion of the
carrier 10 may be provided by making the teeth of the planet gears 6 in the array a circumferentially narrower than the teeth of the planet gears 8 in the array b (FIG. 8B ), resulting in a larger backlash for the planet pinions 6 than for the planet pinions 8. As a consequence, when no or little torque is transmitted, the teeth of the planet pinions 8 engage the sun and ring gears 2 and 4 in the sense that they actually contact the teeth of the sun and ring gears 2 and 4. But the planet pinions 6, while meshing with the sun and ring gears 2 and 4, do not actually engage thosegears -
lb<2la - As the torque increases, the
secondary wall 22 and theweb 24 of the more flexible array b flex enough to displace theflexpins 30 for thepinions 8 of the array b angularly with respect to theflexpins 30 for thepinions 6 of the array a. The narrower teeth of thepinions 6 actually engage the teeth of the sun and ring gears 2 and 4 in the sense that they contact the teeth of the sun and ring gears 2 and 4. At this juncture, torque transfers through the planet pinions 6 and 8 of both arrays a and b. When the torque transferred reaches the magnitude for which the system A is designed to operate, the flexure of thesecondary wall 22 andwebs 24 is such that the planet pinions 6 and the planet pinions 8 share the torque transfer essentially equally, that is to say, one-half transfers through thepinions 6 of the array a and the other half transfers through thepinions 8 of the array b. This alternative provides compensation irrespective of the direction in which the external torque is applied to thecarrier 10. - In another alternative, compensation for the distortion along the
secondary wall 22 andwebs 24 is provided by rendering theprimary wall 20 more flexible where theflexpins 30 for thatwall 20 emerge from it. This, in effect, allows theflexpins 30 on theprimary wall 20, when the gear system A transmits torque, to undergo about the same amount of deflection as theflexpins 30 on thesecondary wall 22. To this end, theprimary wall 20 at each flexpin 30 has an area of weakness in the form of a pair of arcuate cutouts or slots 40 (FIG. 9 ) of equal radius and length, with their centers being at the axes Y for theflexpin 30. Theslots 40, which open out of both faces of thewall 20, are arranged 180° apart with their centers generally located along a circle C that circumscribes the axes Y of theseveral pins 30 and having its center at the central axis X. In other words, oneslot 40 lies circumferentially ahead of thepin 30 and theother slot 40 lies circumferentially behind thepin 30. Thus, theslots 40 impart more flexibility to theprimary wall 20 where theflexpins 30 extend from it than does thesecondary wall 22 where theflexpins 30 emerge from it. This selective weakness approach gives theflexpins 30 of theprimary wall 20 essentially the same deflective characteristics as theflexpins 30 on thesecondary wall 22. This in turn renders the two arrays a and b equally stiff—or equally flexible—so that thepinions 6 of the array a and thepinions 8 of the array b mesh evenly with thesun gear 2 andring gear 4 and thepinions - The
primary wall 20 may also be rendered more flexible at itsflexpins 30 with arcuate grooves 44 (FIG. 10 ) that open out of only one face of theprimary wall 20 instead of both faces as do theslots 40. Like theslots 40, thegrooves 44 should leave theflexpins 30 of theprimary wall 20 with essentially the same deflective characteristics as theflexpins 30 of thesecondary wall 22, so that thepinions - Neither the
slots 40 nor thegrooves 44 need to be arcuate in configuration, but they should render theprimary wall 20 more flexible to the sides of theflexpins 30 along which they are located. Shapes other than slots or grooves will also suffice if they enable theflexpins 30 with which they are identified to deflect more easily in the circumferential direction, reference being to the central axis X. For example, theprimary wall 20 may have a region of thinner cross section, not necessarily resembling an arc, at the side or sides of eachflexpin 30. The shapes, whether they be theslots 40 or thegrooves 44 or some other configuration, may reside only to one side of each flexpin 30 in theprimary wall 20. - In lieu of compensating at the
primary wall 20 for the variations in the lengths of the two load paths pa and pb, the compensation may be at theflexpins 30 themselves. An alternative carrier 50 (FIGS. 11 & 12 ) has aprimary wall 20 and asecondary wall 22, withwebs 24 extending between the twowalls primary wall 20 is devoid of anyslots 40 orgrooves 44 or other shapes designed to impart greater flexibility to thewall 20 itself. However, thepinions 6 of the array a rotate about flexpins 30 a that differ from flexpins 30 b about which thepinions 8 of the array b rotate. The difference resides in the flexibility of thepins pins 30 a for the array a are more flexible than thepins 30 b for the array b. To this end, eachpin FIG. 12 ) abase 52 where it is fitted into thewall pins head 54 at the opposite end of thepins base 52 and itshead 54, eachpin shank 56. Thesleeve 32 that surrounds thepin head 54 and may even be formed integral with thehead 54. Theshank 56 tapers downwardly from thebase 52 and from thehead 54 to a necked-inregion 58. The diameter for the necked-inregion 58 of eachpin 30 b that projects from thesecondary wall 22 exceeds the diameter for the necked-inregion 58 for eachpin 30 a that projects from theprimary wall 20. This imparts greater flexibility to thepins 30 a. The arrangement is such that the deflection of thepins 30 b occasioned by the distortion of thesecondary wall 22 andwebs 32 under load equals the deflection of the moreflexible pins 30 a, so that thepinions pins pinions - The flexpins 30 a may be rendered more flexible than the
flexpins 30 b without reducing the diameter of their necked-inregions 58. For example, theflexpins 30 may be hollow or partially hollow, while theflexpins 30 b are solid throughout. Also, the flexpins 30 a may be formed from a material that flexes more easily than the material from which theflexpins 30 b are formed. Then again, a combination of the foregoing, including variance in diameters of the necked-inregions 58, may be employed. The object is to render the flexpins 30 a more flexible than theflexpins 30 b irrespective of the manner in which it is achieved. - In the
carrier 10, the same effect may be achieved by making thegrooves 36 in theflexpins 30 at theprimary wall 20 deeper than thegrooves 36 in theflexpins 30 at thesecondary wall 22. Indeed, by so configuring theflexpins 30 of theprimary wall 20, thearcuate slots 40 orgrooves 44 may be eliminated or diminished in size. - The
carrier 50 with flexpins 30 a and 30 b of different flexibility in itsprimary wall 20 may be provided witharcuate slots 40 orgrooves 44 or other shapes to impart greater flexibility to theprimary wall 20 at its flexpins 30 a. In that arrangement, the desired deflective characteristics for the flexpins 30 a of the array a are derived from both theprimary wall 20 and the greater flexibility of the flexpins 30 a that project from thewall 20. This arrangement for balancing the deflection of the flexpins 30 a and 30 b represents a combination of the selected wall weakness approach and the variance-in-pin stiffness approach. - The external torque need not be applied to either
carrier primary wall 20, but instead elsewhere on thewall 20, such as through a hub 64 (FIG. 13 ) that serves as a coupling region on thewall 20. Again the load path pb for the array b is longer than the load path pa for the array a. Similar distortions in thesecondary wall 22 andwebs 24 occur.
Claims (20)
1. An epicyclic gear system comprising:
a sun gear having an axis;
a ring gear surrounding the sun gear and having an axis that coincides with the axis of the sun gear;
first planet pinions meshing with the sun and ring gears in a first array;
second planet pinions meshing with the sun and ring gears in a second array that is offset axially from the first array; and
a carrier having first flexpins coupled to the first planet pinions and second flexpins coupled to the second planet pinions, the carrier further having a coupling region at which torque is applied to the carrier when the gear system is subjected to a load, with the torque transferring between the coupling region and the first flexpins through first load paths and between the coupling region and the second flexpins through second load paths that are longer than the first load paths, and with the difference in lengths of the load paths causing a distortion in the carrier,
and means for compensating for the distortion to enable the first and second pinions to mesh more evenly with the sun and ring gears when torque is applied to the carrier.
2. An epicyclic gear system according to claim 1 wherein the means for compensating comprises an angular offset of the first flexpins from the second flexpins in the absence of torque applied to the carrier.
3. An epicyclic gear system according to claim 1 wherein the means for compensating comprises the teeth on the first pinions being narrower than the teeth on the second pinions.
4. An epicyclic gear system according to claim 1 wherein the means for compensating enables the first flexpins and the second flexpins to undergo substantially the same deflection when torque is transferred in spite of distortion in the carrier caused by differences in the length of the load paths.
5. An epicyclic gear system according to claim 4 wherein the means for compensating comprises areas of weakness in the carrier at the first flexpins.
6. An epicyclic gear system according to claim 4 wherein the means for compensating comprises the first flexpins being more flexible than the second flexpins.
7. An epicyclic gear system according to claim 1 wherein the carrier has first and second walls and webs connecting the walls; and wherein the first flexpins are cantilevered from the first wall and the second flexpins are cantilevered from the second wall.
8. An epicyclic gear system according to claim 7 wherein the means for compensating includes areas of weakness in the first wall where the first flexpins are cantilevered from the first wall.
9. An epicyclic gear system according to claim 8 wherein the areas of weakness are formed by slots or grooves in the first wall.
10. An epicyclic gear system according to claim 9 wherein the slots or grooves are arcuate and follow the contour of the first flexpins.
11. An epicyclic gear system according to claim 9 wherein the slots or grooves lie along a circle that circumscribes the axes of the first flexpins.
12. An epicyclic gear system comprising:
a sun gear having an axis;
a ring gear surrounding the sun gear and having an axis that coincides with the axis of the sun gear;
first planet pinions meshing with the sun and ring gears in a first array;
second planet pinions meshing with the sun and ring gears in a second array that is offset axially from the first array; and
a carrier including:
a first wall;
a second wall spaced axially from the first wall;
webs connecting the first and second walls;
first flexpins cantilevered from the first wall and projecting into the first pinions;
sleeves interposed between the first flexpins and the first pinions and being cantilevered from the ends of the first flexpins that are remote from the first wall;
second flexpins cantilevered from the second wall and projecting into the second pinions;
more sleeves interposed between the second flexpins and the second pinions and being cantilevered from the ends of the second flexpins that are remote from the second wall; and
a coupling region at which the carrier is subjected to a torque when a load is transferred through the gear system, with that torque transferring to the first pinions through first load paths that pass through the first flexpins and transferring to the second pinions through second load paths that pass through the second flexpins, the second load paths being longer than the first load paths and causing a greater distortion of the carrier along the second load paths than along the first load paths when a load is transferred through the gear system; and
means for compensating for the greater distortion along the second load paths than along the first load paths to enable the first and second pinions to mesh more evenly with the sun and ring gears in spite of the distortion.
13. An epicyclic gear system according to claim 12 wherein the means for compensating comprises an angular offset of the first flexpins from the second flexpins in the absence of torque applied to the carrier.
14. An epicyclic gear system according to claim 12 wherein the means for compensating comprises the teeth on the first pinions being narrower than the teeth on the second pinions.
15. An epicyclic gear system according to claim 12 wherein the means for compensating includes areas of weakness in the first wall where the first flexpins are cantilevered from the first wall.
16. An epicyclic gear system according to claim 15 wherein the areas of weakness are formed by slots or grooves in the first wall adjacent the first flexpins.
17. An epicyclic gear system according to claim 16 wherein the slots or grooves are arcuate and follow the contour of the first pins.
18. An epicyclic gear system according to claim 16 wherein the slots or grooves lie along a circle that circumscribes the axes of the first flexpins.
19. An epicyclic gear system according to claim 12 wherein the means for compensating comprises the first flexpins being more flexible than the second flexpins.
20. An epicyclic gear system comprising:
a sun gear having an axis;
a ring gear surrounding the sun gear and having an axis that coincides with the axis of the sun gear;
first planet pinions meshing with the sun and ring gears in a first array;
second planet pinions meshing with the sun and ring gears in a second array that is offset axially from the first array; and
a carrier having first flexpins coupled to the first planet pinions and second flexpins coupled to the second planet pinions, the carrier further having a coupling region at which torque is applied to the carrier when the gear system is subjected to a load, with the torque transferring between the coupling region and the first flexpins through first load paths and between the coupling region and the second flexpins through second load paths, the first load paths being stiffer than the second load paths with the difference in the stiffness of the load paths causing a distortion in the carrier,
and means for compensating for the distortion to enable the first and second pinions to mesh more evenly with the sun and ring gears when torque is applied to the carrier.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US12/866,499 US20110053730A1 (en) | 2008-02-13 | 2009-02-12 | Epicyclic Gear System Having Two Arrays Of Pinions Mounted On Flexpins With Compensation For Carrier Distortion |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US2827408P | 2008-02-13 | 2008-02-13 | |
US12571508P | 2008-04-28 | 2008-04-28 | |
US12/866,499 US20110053730A1 (en) | 2008-02-13 | 2009-02-12 | Epicyclic Gear System Having Two Arrays Of Pinions Mounted On Flexpins With Compensation For Carrier Distortion |
PCT/US2009/033896 WO2009102853A1 (en) | 2008-02-13 | 2009-02-12 | Epicyclic gear system having two arrays of pinions mounted on flexpins with compensation for carrier distortion |
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PCT/US2009/033896 A-371-Of-International WO2009102853A1 (en) | 2008-02-13 | 2009-02-12 | Epicyclic gear system having two arrays of pinions mounted on flexpins with compensation for carrier distortion |
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US14/083,970 Continuation US9145967B2 (en) | 2008-02-13 | 2013-11-19 | Epicyclic gear system having two arrays of pinions mounted on flexpins with compensation for carrier distortion |
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US20110053730A1 true US20110053730A1 (en) | 2011-03-03 |
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US12/866,499 Abandoned US20110053730A1 (en) | 2008-02-13 | 2009-02-12 | Epicyclic Gear System Having Two Arrays Of Pinions Mounted On Flexpins With Compensation For Carrier Distortion |
US14/083,970 Active 2029-04-09 US9145967B2 (en) | 2008-02-13 | 2013-11-19 | Epicyclic gear system having two arrays of pinions mounted on flexpins with compensation for carrier distortion |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/083,970 Active 2029-04-09 US9145967B2 (en) | 2008-02-13 | 2013-11-19 | Epicyclic gear system having two arrays of pinions mounted on flexpins with compensation for carrier distortion |
Country Status (5)
Country | Link |
---|---|
US (2) | US20110053730A1 (en) |
EP (1) | EP2252809B1 (en) |
KR (1) | KR101553726B1 (en) |
CN (2) | CN101932851A (en) |
WO (1) | WO2009102853A1 (en) |
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Publication number | Priority date | Publication date | Assignee | Title |
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US20110039654A1 (en) * | 2008-04-30 | 2011-02-17 | The Timken Company | Epicyclic Gear System With Flexpins |
US8430788B2 (en) * | 2008-04-30 | 2013-04-30 | The Timken Company | Epicyclic gear system with flexpins |
US20110315450A1 (en) * | 2009-12-21 | 2011-12-29 | Joachim Sihler | Coiled tubing orienter tool with high torque planetary gear stage design drive |
US8714245B2 (en) * | 2009-12-21 | 2014-05-06 | Schlumberger Technology Corporation | Coiled tubing orienter tool with high torque planetary gear stage design drive |
US8536726B2 (en) * | 2010-09-17 | 2013-09-17 | Vestas Wind Systems A/S | Electrical machines, wind turbines, and methods for operating an electrical machine |
US20120068472A1 (en) * | 2010-09-17 | 2012-03-22 | Vestas Wind Systems A/S | Electrical machines, wind turbines, and methods for operating an electrical machine |
EP2518371A1 (en) | 2011-04-29 | 2012-10-31 | General Electric Company | Planet pin and planetary gear system |
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EP2532919A2 (en) | 2011-06-08 | 2012-12-12 | General Electric Company | Planetary gear system |
EP2532928A1 (en) | 2011-06-08 | 2012-12-12 | General Electric Company | Compliant carrier wall for improved gearbox load sharing |
EP2559917A1 (en) * | 2011-08-16 | 2013-02-20 | General Electric Company | Pin for planetary gear system |
US8506446B2 (en) | 2011-08-16 | 2013-08-13 | General Electric Company | Pin for planetary gear system |
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US10323719B2 (en) | 2012-04-03 | 2019-06-18 | Ricoh Company, Ltd. | Planetary gear assembly, drive unit including the planetary gear assembly, and image forming apparatus including the drive unit, and installation method for planetary gear assembly |
US20130260952A1 (en) * | 2012-04-03 | 2013-10-03 | Ricoh Company, Ltd. | Planetary gear assembly, drive unit including the planetary gear assembly, and image forming apparatus including the drive unit, and installation method for planetary gear assembly |
WO2014182467A1 (en) * | 2013-05-08 | 2014-11-13 | United Technologies Corporation | Fan drive gear system with improved misalignment capability |
JP2016520179A (en) * | 2013-05-08 | 2016-07-11 | ユナイテッド テクノロジーズ コーポレイションUnited Technologies Corporation | Fan drive gear system with improved misalignment |
US10145259B2 (en) | 2013-05-08 | 2018-12-04 | United Technologies Corporation | Fan drive gear system with improved misalignment capability |
US11008885B2 (en) | 2013-05-08 | 2021-05-18 | Raytheon Technologies Corporation | Fan drive gear system with improved misalignment capability |
US11686209B2 (en) | 2013-05-08 | 2023-06-27 | Raytheon Technologies Corporation | Fan drive gear system with improved misalignment capability |
CN106662213A (en) * | 2014-07-07 | 2017-05-10 | 舍弗勒技术股份两合公司 | Circular sliding planetary gear train |
US20190211908A1 (en) * | 2016-09-06 | 2019-07-11 | Schaeffler Technologies AG & Co. KG | Planetary gearing system, in particular reduction gear with integrated spur gear differential |
US10920864B2 (en) * | 2016-09-06 | 2021-02-16 | Schaeffler Technologies AG & Co. KG | Planetary gearing system, in particular reduction gear with integrated spur gear differential |
CN111316017A (en) * | 2017-11-06 | 2020-06-19 | 采埃孚股份公司 | Planetary carrier with flexible bolt-shaped piece |
US11204079B2 (en) * | 2019-02-19 | 2021-12-21 | Moventas Gears Oy | Planetary gear |
CN110230688A (en) * | 2019-07-19 | 2019-09-13 | 南京高速齿轮制造有限公司 | Planetary gear mechanism |
Also Published As
Publication number | Publication date |
---|---|
CN101932851A (en) | 2010-12-29 |
US20140171255A1 (en) | 2014-06-19 |
WO2009102853A1 (en) | 2009-08-20 |
CN104235273B (en) | 2017-04-12 |
EP2252809A1 (en) | 2010-11-24 |
CN104235273A (en) | 2014-12-24 |
KR20100124716A (en) | 2010-11-29 |
EP2252809B1 (en) | 2016-01-13 |
US9145967B2 (en) | 2015-09-29 |
KR101553726B1 (en) | 2015-09-16 |
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