Planetary gear carrier arrangement

Abstract

Planetary gear carrier arrangement (10, 100) comprising in combination: a planetary gear carrier (20) defining an axis and having a plurality of pairs of aligned, spaced-apart bores (42), a pinion receiving area between a pair of spaced-apart bores (42), a pinion (30) arranged in each pinion receiving area and meshing with a ring gear (86) and a sun gear (16) driven by a hollow drive shaft (12), a low-friction bearing (32) arranged in each pinion (30), a planetary gear pin (140) disposed within the low-friction bearing (32) and received within one of the pairs of aligned bores (42), the planetary gear pin (140) including an axial bore opening (144) at one end communicating with a radial bore (146) and a flat (150) at the other end, the radial bore (146) being oriented perpendicular to the flat (50), and means for engaging the flat (150) of the planetary gear pin (140) and maintaining the radial bore (146) of the planetary gear pin (40) in a radially outward orientation relative to the carrier axis; characterized in that the ring gear (86) is supported by a hub (92) which is guided on the hollow drive shaft (12); wherein the flattening (150) of the planetary gear bolt (140) points radially inward; wherein the means for engaging and maintaining is an L-shaped ring (160) having an outer edge that engages the flat (150) and a snap ring (166) for securing the L-shaped ring (160) to the carrier (20); and wherein the L-shaped ring (160) has a radially extending leg (172) and an axially extending leg (162) forming the outer edge that engages the flat (150).

Description

REGIONThe present disclosure relates to a planet carrier arrangement according to the preamble of claim 1, as known, for example, from DE 10 2006 009 622 A1.Further means for engaging are described, for example, in the publications DE 691 00 321 T2, US 2001 / 0 012 808 A1 or DE 690 06 665 T2. With regard to the further state of the art, reference is made at this point to the publications U.S. Pat. No. 6,033,335 A, DE 697 07 633 T2 and U.S. Pat. No. 4,756,212 A.BACKGROUNDPlanetary gear assemblies are remarkably versatile and adaptable devices. Various automotive final drive components, such as transmissions, differentials, and transmission / differential units, often and generally utilize planetary gear assemblies. Typically, they are used either alone to provide speed reduction and torque increase or in tandem and are associated with clutches and brakes that connect or ground various elements of the planetary gear assemblies to provide multiple speed reductions and torque multiplications.A simple planet carrier assembly includes a centrally located sun gear, a planet carrier generally disposed about the sun gear, and a ring gear disposed about the carrier. A plurality of planet gears rotatably mounted on shafts, also referred to herein as a planet pin, stub shaft, or bore shaft, within the carrier are engaged with both the sun gear and the ring gear.Thus, there are, of course, many technical problems in the design and fabrication of planetary gear assemblies. One concerns the manner by which the planet shafts are held or secured to and within the planet carrier. One approach is to provide small holes through the shaft and the carrier that can be aligned and through which a retaining pin can be inserted. Another approach includes deforming, e.g., by riveting, the pinion shaft to the carrier. These two approaches require suitable wave-adjacent regions of the beam that can receive either the pin or the deformed region of the wave and thus may not be suitable in many cases.Another technical problem relates to lubrication. In certain configurations and in certain vehicle speed ranges, the speed of the planetary or pinion gears of a given planetary gear arrangement may be quite significant, i.e., many thousand revolutions per minute. The speed of the planet carrier can also be quite high. High planetary or pinion gear speeds are not problematic per se, but require sufficient lubrication to not only lubricate the pinion-bearing-pinion shaft interface, but also dissipate the heat generated by such rapid rotation of the interface.The present invention is directed to the provision of an improved holder which not only holds pinion shafts in a planet carrier but also maintains their angular orientation which provides improved bearing lubrication.The invention is based on the object of improving a planetary gear carrier arrangement of the generic type with regard to its rigidity properties.SUMMARYThis object is achieved with a planet carrier arrangement having the features of claim 1.The present invention provides a pinion shaft holder for a planet carrier of a planetary gear assembly which both retains the pinion shaft within the carrier and maintains its angular positions to achieve improved oil flow to the pinion bearings. Each of the pinion shafts includes an axial passage communicating with a radial passage near the center of the shaft. At the end of the pinion shaft opposite the axial through-opening, there is a flattened portion which extends over the shaft. The flat is normal to the axis of the radial passage. The pinion shafts are slidably seated in suitable bores in the planet carrier and support a cage roller bearing or needle bearing and a planet or pinion gear, as is known, for example, from DE 11 205 001 874 T5.At one end of the carrier, the flats engage a circular retainer such that the radial passages of each of the pinion shafts are oriented radially outward. The circular holder has an L-shaped cross section. The circular bracket may be fixed to the planet carrier by a snap ring or by a plurality of fasteners such as bolts or machine screws. A lubricant barrier is secured to the planet gear carrier at the opposite end of the carrier and directs a flow of lubricating oil from a source such as from a hollow drive shaft to the open ends of the axial passages of the pinion shafts. By maintaining the radially outward orientations of the radial pinion shaft passages, the flow of lubricating oil to the pinion shaft-bearing-pinion interfaces is substantially unaffected by the rotational speed of the planet carrier.Thus, it is an aspect of the invention to provide a planet carrier having improved pinion shaft bearing-pinion lubrication for a planet gear assembly.It is another aspect of the present invention to provide a pinion shaft for a planet carrier of a planetary gear assembly having an axial passage extending from one end to a radial passage near the center of the shaft.It is yet another aspect of the present invention to provide a planet carrier having a circular retainer that holds a plurality of pinion shafts in a desired rotational orientation.It is yet another aspect of the present invention to provide a planet carrier having a circular retainer that holds a plurality of pinions having a radial lubrication opening in a desired rotational orientation.It is yet another aspect of the present invention to provide a planet carrier having a circular retainer that engages flats on the ends of a plurality of pinion shafts to maintain them in a desired rotational orientation.It is yet another aspect of the present invention to provide a planet carrier having a circular retainer engaging flats on the ends of a plurality of pinion shafts that include radial lubrication passages to maintain the radial passages in a radially outward orientation.Other aspects, advantages and areas of applicability will become apparent from the description provided herein. It is to be understood that the specification and specific examples are given by way of illustration only.DRAWINGSThe drawings described herein are for illustrative purposes only. FIG. 1 is a partial cross-sectional view of a portion of a planetary gear assembly including a pinion shaft and a circular flat retainer, in accordance with the present invention, secured to the planetary gear carrier by a snap ring; FIG. 2 is an enlarged partial perspective view of a portion of a pinion shaft and a circular retaining plate of FIG. 1 ; FIG. 3 is a partial cross-sectional view of a portion of a planetary gear assembly including a pinion shaft and a circular L-shaped retaining ring in accordance with an embodiment of the present invention; and FIG. 4 is a partial cross-sectional view of a portion of a planetary gear assembly including a pinion shaft and a circular L-shaped retaining ring in accordance with the present invention secured to the planetary gear carrier by machine bolts or screws.DETAILED DESCRIPTIONThe following description is merely exemplary in nature.Referring now to Fig. 1, an embodiment of the present invention is illustrated in conjunction with a portion of a planetary gear assembly designated by the reference numeral 10. The planetary gear assembly 10 includes a input sleeve 12 having a spline 14 that couples and drives a sun gear 16 having a spline 18 and a planet carrier 20. The planet carrier 20 includes an annular extension 22 having a spline or gear 24 which engages associated drive members or driven members 26. The planet carrier 20, and particularly the annular extension 22, is freely rotatably supported by a ball bearing assembly 28.The planet carrier 20 also includes a plurality of planet or pinion gears 30 that are received on low friction bearings such as cage, roller bearing or needle bearing assemblies 32. The roller or needle bearing assemblies 32 are, in turn, received on a respective plurality of shaft stubs or pinion shafts 40 that are received within a plurality of pairs of spaced-apart aligned bores 42 in the planet carrier 20. The number of planetary or pinion gears 30, bearing assemblies 32, stub shafts or pinion shafts 40 and pairs of aligned bores 42 may be three, four, five, six or more depending on the torque load of the planetary gear assembly 10 and other design parameters. Typically and preferably, the plurality of pairs of aligned bores 42, the shaft stubs or pinion shafts 40, the bearing assemblies 32, and the planetary or pinion gears 30 are parallel to and equiangularly disposed about the common axis of the input shaft 12 and the planet carrier 20. For example, if there are six of each of the above-mentioned components, they are preferably spaced at 60° intervals about the common axis of the input shaft 12 and the planet carrier 20.As shown in FIGS. 1 and 2, the shaft stubs or pinion shafts 40 each include a concentric axial bore or passage 44 that opens at one end of the shaft 40 and extends along the axis of the shaft 40 approximately to its center. Near or at the axial center of pinion shaft 40, axial passage 44 intersects a radial bore or passage 46, which preferably has the same diameter as axial passage 44. Thus, the intersecting axial and radial passages 44 and 46 provide fluid communication between an end of the stub shaft or pinion shaft 40 and a point on its outer surface at or near its axial midpoint.At the end of each of the shaft stubs or pinion shafts 40 opposite the opening of the axial bore or passage 44 is a diametrical surface 50, i.e., a flat surface, which preferably coincides with or passes through the center of the shaft 40. However, it should be appreciated that the diametrical surface 50 need not coincide with a diameter, but may be the chord surface of slightly shorter length on either side of the diameter. Moreover, the diametrical surface 50 may be slightly curved or convex, if desired. Although the diametrical surface 50 is axially spaced from the radial passage 46, it is perpendicular to the axis of the radial passage 46. in the noninventive embodiment of Figs. 1 and 2, the diametrical surface 50 faces radially outward.Thus, the radial passage 46 is also oriented radially outward when the surface 50 is maintained in a radially outward orientation.The diametrical surfaces 50 of the stub shafts or pinion shafts 40 and thus the radial passages 46 are held in a radially outward orientation by a circular retainer plate 60. The circular support plate 60 is disposed between the surfaces 50 of each of the pinion shafts 40 and a flat groove or shoulder 62 extending around the planet carrier 20. An adjacent channel 64 receives a snap ring 66 which retains the circular retaining plate 60 within the planet carrier 20.As noted above, the input shaft 12 is hollow and is pressurized with lubricating oil or hydraulic fluid. A radial port 72 in the wall of the input shaft 12 directs pressurized fluid into a radial passage 74. A pair of rotating seals 76 maintain a fluid tight seal between the input shaft 12 and the components within the planetary gear assembly 10. A lubricant lock 78 directs lubricating fluid radially outwardly to a plurality of axial ports 82 aligned with the bores 42 in the planet carrier 20 and with the axial passages 44 in the shaft stubs or pinion shafts 40. Thus, lubrication is provided directly to the pinion / bearing / shaft interface. Moreover, the radial passage 46 providing this lubrication is maintained in a radially outward orientation which minimizes the effect of high speed planetary gear carrier 20 on lubricant flow.The planetary gear assembly 10 also includes a ring gear 86 having a toothing 88 that meshes with the planetary or pinion gears 30. The ring gear 86 may be supported by a hub or ring gear 92 that is carried on the input shaft 12. The spline 94 on the ring gear 86 engages associated components 96 of the planetary gear assembly 10.Referring now to Fig. 3, a pinion pin holder of an embodiment of the present invention is shown and designated by the reference numeral 100. Typically, the pin holder 100 of this embodiment of the invention may be and may be used with a planetary gear assembly 10 substantially the same as the planetary gear assembly 10 described above. Thus, the planetary gear assembly 10 includes the input sleeve shaft 12, the sun gear 16, a planet carrier 20, the annular extension 22, the ball bearing assembly 28, the planetary or pinion gears 30, the cage roller bearings or needle bearings 32, the pairs of aligned bores 42, the ring gear 86 and the hub or ring 92, as well as the other associated elements described above, and other components specifically described below that are different from the embodiment not according to the invention.The pinion pin holder 100 of the embodiment of the present invention includes a plurality of shaft stubs or pinion shafts 140. As noted above, depending on the torque load and other design parameters of the particular assembly 10, there may be three, four, five, six, or more stub shafts or pinion shafts 140 (and the associated pinion gears 30 and bearings 32). Each of the stub shafts 140 includes a concentric axial passage 144 extending from one end of the shaft 140 to approximately its axial center. A radial passage, which preferably has the same diameter as axial passage 144, intersects axial passage 144 approximately at the center of shaft 140. At the end of shaft 140 opposite axial passage 144 is diametrical surface 150. Although surface 150 is preferably a plane having a diameter, it may again be a shorter length chord surface on either side of a diameter. In embodiment 100 of the invention, surface 150 may also be slightly curved or concave. Moreover, in the embodiment 100 of the invention, the diametrical surface 150 faces radially inward. That is, with respect to the non-inventive embodiment and shafts 40 in which the radial passages 46 and surfaces 50 are all directed or face radially outward, the radial passages 146 and surfaces 150 of the shafts 140 of the inventive embodiment 100 face in opposite radial directions.An L-shaped retaining ring 160 engages the diametrical surfaces 150 of the shaft stubs or pinion shafts 140 and inhibits their rotation. The L-shaped retaining ring 160 includes a first axially extending leg or portion 162 that abuts or engages a snap ring 166 seated or received within a groove or channel 168 in the planet carrier 20. The snap ring 166 retains the L-shaped retaining ring 160 in place against the stub shafts or pinion shafts 140. The L-shaped retaining ring 160 also includes a second radially extending leg or portion 172 that engages both the shafts 140 and the planet carrier 20.Embodiment 100 of the invention also includes radial port 72 in input or drive shaft 12, passage 74, pair of axially spaced rotating seals 76, and lubricant barrier 78, thus providing pressurized oil or other lubricating fluid through radial port 72, between seals 76, along lubricant barrier 78, into axial passages 144, and through radial passages 146, which are always oriented radially outward.Perhaps it should be explained and at any rate recognized that although the circular support plate 60 and the L-shaped support ring 160 are referred to throughout this text as a "retainer", they both not only support the stub shafts or pinion shafts 40 and 140 within the planet carriers 20 but also specifically maintain the radially outward orientation of the radial passages 46 and 146 relative to the axes of the planet carriers 20 as described above.Referring now to Figures 3 and 4, an alternative attachment means is shown for either the circular retainer plate 60 or the L-shaped retainer ring 160. In this mounting configuration, the snap rings 66 and 166 and the channels 64 and 168 in the planet carriers 20 are omitted. In place, there are a plurality of threaded fasteners such as machine bolts or cap screws 182 which pass through a like plurality of apertures 184 in the circular support plate 60 or in the L-shaped support ring 160 (shown) and into complementary threaded apertures 186 in the planet carrier 20 (shown). The plurality of threaded fasteners 182, the apertures 184, and the threaded apertures 186 are preferably disposed at equal angular intervals about the axis of the planet carrier 20. Thus, the circular retaining plate 60 or the L-shaped retaining ring 160 are secured to the planet carrier 20 by a plurality of releasable threaded fasteners 182, but function in the same manner as described above to both retain the stub shafts or pinion shafts 40 and 140 within the planet carriers 20 and maintain the radially outward orientation of the radial passages 46 and 146.

Claims

A planet carrier assembly (10, 100) comprising in combination: a planet carrier (20) defining an axis and having a plurality of pairs of aligned spaced bores (42), a pinion receiving region between a pair of spaced bores (42), a pinion (30) disposed in each pinion receiving region and engaging a ring gear (86) and a sun gear (16) driven by a input sleeve shaft (12), a low friction bearing (32) disposed in each pinion (30), a planet pin (140) disposed within the low friction bearing (32) and received within one of the pairs of aligned bores (42), the planet pin (140) having an axial bore opening (144) at one end communicating with a radial bore (146), and including a flat (150) at the other end, the radial bore (146) being oriented perpendicular to the flat (50), and means for engaging the flat (150) of the planet gear pin (140) and maintaining the radial bore (146) of the planet gear pin (40) in a radially outward orientation relative to the carrier axis; characterized in that the ring gear (86) is supported by a hub (92) guided on the input ring shaft (12); the flat (150) of the planet gear pin (140) facing radially inward; wherein the means for engaging and maintaining is an L-shaped ring (160) having an outer edge engaging the flat (150) and a snap ring (166) for securing the L-shaped ring (160) to the carrier (20); and wherein the L-shaped ring (160) has a radially extending leg (172) and an axially extending leg (162) forming the outer edge engaging the flat (150).The planet carrier assembly of claim 1, wherein the low friction bearing (32) is a cage needle bearing assembly.

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