PLANET CARRIER ASSEMBLY

Abstract: A planet carrier assembly (10) has a pair of spaced parallel side plates (12,14) interconnected by a body (12) with a plurality of aligned aperture pairs (26,28) formed in the side plates for receiving mounting spindles (24) on which pinion gear members (22) are rotatably supported. Each spindle has a shoulder (36) which contacts a locating surface (40) on one side plate to limit axial movement of the spindle in one direction relative to the side plates. A segmental space (42) is provided at the longitudinal end of each spindle adjacent the shoulder and each space is arranged such that a flat surface thereof faces radially outward at assembly. A retainer plate (54) having complementary radially extending locating surfaces cooperate with the flat surfaces of the segmental spaces to limit rotation of the spindle relative to the side plates. A retaining ring (58) is secured in one side plate adjacent the retainer plate to limit axial movement of the spindles in the other direction relative to the side plates.

Description: This invention relates to planet assemblies, and more particularly, to planetary carrier gear assemblies. Specifically, this invention relates to planetary gear assemblies wherein the mounting spindles for the pinion gears are limited in relative rotary and axial movement in the carrier assembly. The prior art gear carrier structures generally prevent relative rotation and axial movement of the spindles by welding or staking the spindles to the carrier side plates. An improvement on this prior art assembly is disclosed in US-A-4,756,212. This patent teaches the use of a flat surface and a locking ring disposed in combination to limit the rotary motion and axial motion of the spindle relative to the carrier in one direction. The spindles are mounted in aligned apertures, wherein the one opposite the locking ring structure is drilled with a stepped diameter to limit the axial motion in one direction. This structure requires some care in the drilling of the stepped diameter, since the shoulder created by such structure has to be maintained within a predetermined distance from the retaining ring locating structure in order that excess axial movement does not occur. A planet carrier assembly in accordance with the present invention is characterised over this prior art by the features specified in the characterising portion of claim 1. The present invention provides an improvement over the prior art by establishing the rotary and axial movement constraints on one end of the spindle structure. This permits the mounting apertures in the planet carrier assembly to be a single constant diameter which allows reduced manufacturing cost. The relative rotary motion of the spindle within the planet carrier assembly is constrained by a longitudinally extending flat surface on the spindle, and a retainer plate having a complementary cooperating surface. The relative axial motion is constrained in one direction by a shoulder formed on the spindle adjacent the flat surface, and a retaining ring secured in the side plate and in axial abutment with the retainer plate. This improvement permits one of the carrier side plates to be made thinner than is possible with the prior art, thereby reducing the axial length of the carrier assembly and simultaneously reducing the weight and material usage. It is therefore an object of this invention to provide an improved planet carrier assembly, wherein the pinion gears are rotatably mounted between side plates on substantially cylindrical spindles having structure on one end thereof, for constraining the rotary and axial movement of the spindles relative to the other components of the planet carrier assembly. This invention preferably provides a planet carrier assembly, wherein each spindle has a radially extending shoulder on the one end and a longitudinally extending flat surface, radially opposite the shoulder, and further wherein the shoulder cooperates with one side plate to limit axial movement in one direction and the flat surface cooperates with a retainer plate having a complementary flat surface and a retaining ring secured in the side plate to limit axial movement in another direction and to also limit rotary movement of the spindle relative to the side plate. This invention provides an improved retaining and movement limiting structure for a planet carrier assembly having spaced side plates with pinion gears rotatably supported on spindles therebetween, wherein each spindle has a shoulder structure abutting a locating surface on one side plate and a longitudinally extending flat surface adjacent the shoulder, and further wherein a retainer plate having a complementary flat surface and a retaining ring secured in the one side plate cooperate with the spindle to limit rotary and axial movement of the spindle relative to the side plate. The present invention will now be described by way of example, with reference to the following description, and the accompanying drawings, in which:- Figure 1 is a cross-sectional elevational view of a planet carrier assembly incorporating an exemplary embodiment of the present invention; Figure 2 is an enlarged sectional view of a portion of Figure 1; Figure 3 is an end view of the structure shown in Figure 2; and Figure 4 is a view similar to Figure 2 depicting an alternative embodiment of retaining means for the spindle of the present invention. Referring to the drawings, there is seen in Figure 1, a planet carrier assembly, generally designated 10, having a body 12 and a pair of radially extending side walls or plates 14 and 16 which are formed integrally with the body 12. The body 12 has a plurality of openings 18 between the side plates 14 and 16. The side plate 16 has a splined or toothed outer surface 20 which will permit the planet carrier assembly 10 to be drivingly connected to other components, such as a clutch, a brake or another planetary gear arrangement within a power transmission. A plurality of pinion gears 22 are rotatably mounted on spindles 24 which are supported in the side plates 14 and 16. The spindles 24 are generally cylindrical in shape with a constant diameter body portion and are disposed in apertures 26 and 28 in the side plates 14 and 16, respectively. As can be seen in Figures 1 and 2, these apertures 26 and 28 are formed in pairs and are axially aligned to permit assembly of the spindle 24 with the body 12. The pinion gears 22 are rotatably mounted on the spindles 24 by a bushing 30. In the alternative, the bushing 30 can be replaced with needle bearings should this be desirable in a particular gear assembly. A pair of thrust washers 32 and 34 are disposed between the pinion gears 22 and the side plates 14 and 16, respectively. As is well known, the pinion gears 22 quite often have helical teeth such that side loading of the pinions occurs during power transmission. This side loading is accommodated by the bearings or thrust washers 32 and 34. Each spindle 24 has formed on one end thereof, a shoulder 36 (shoulder means) having a slightly larger diameter than the remainder of the spindle 24. A side wall 38 of the shoulder 36 is placed in abutment with a locating surface 40 formed on the side plate 14. As seen in Figures 1 and 2, the shoulder 36 cooperates with the side wall 38 to limit rightward axial or longitudinal movement of the spindle 24 relative to the body 12. The spindle 24 has formed therein, at one end thereof, a segmental space or cut out 42 radially adjacent the shoulder 36. The segmental space 42 has a longitudinally extending flat surface 44 and a radially extending flat surface 46, which define locating flat means. The side plate 14 has an outer annular extension 48 having an inner diametral surface 50 from which is presented a radially outwardly extending groove 52. A retainer plate 54 is disposed axially adjacent the radially extending flat surface 46 and radially adjacent the inner diametral surface 50. As seen best in Figure 3, the retainer plate 54 is generally annular with the inner surface thereof interrupted at spaced locations by flat or chordal surfaces 56 defining alignment surface means. The flat surfaces 56 are complementary to the longitudinally extending flat surfaces 44 and, as best seen in Figure 3, will cooperate therewith to limit the rotary motion of the spindle 24 relative to the side plates 14 and 16. A retaining ring 58 is disposed in the groove 52 adjacent the retainer plate 54, as best seen in Figures 1, 2 and 3. The retaining ring 58 cooperates with the retainer plate 54 and the radially extending flat surface 46 on the spindle 24 to limit the leftward axial or longitudinal movement of the spindle 24 relative to the body 12. Figure 4 depicts an alternate embodiment of the invention, wherein a spindle 24a has a segmental space 42 which cooperates with a retainer plate 54 and a retaining ring 58 to limit the rotary movement of the spindle 24a and the leftward axial movement of the spindle 24a relative to a planet carrier assembly having a side plate 14a. The side plate 14a has formed therein a plurality of cylindrical annular locating surfaces 40a which are coaxial with the axis of the respective spindles 24a. The spindle 24a has formed therein a groove 60 in which is disposed a locking ring 62. The locking ring 62 cooperates with the spindle 24a to establish a shoulder means which is formed longitudinally adjacent the segmental space 42 and is disposed in abutment with the locating surface 40a to limit the rightward axial movement of the spindle 24a. It should be readily apparent after reviewing the above disclosure, that spindles 24 and 24a are constrained from relative motion both axial and rotary relative to the side walls and body of the planet carrier assembly 10. It should also become apparent from the above description that the structure which defines the constraints for the limited motion retention is associated with a single longitudinal end of the spindles 24 and 24a. Therefore, the machining functions or operations which must be undertaken to provide the assembly control surfaces are limited to a very small portion of the carrier structure. The amount of axial constraint will generally be controlled by the retainer plate 54. If desired, this plate can be provided in a number of thickness such that the axial motion of the spindles 24 and 24a can be closely controlled in assembly. In the alternative, the retainer plate 54 might be comprised of a plurality of plate members or shims which are installed selectively to control the axial motion of the spindles.

Claims: A planet carrier assembly comprising a pair of side plates (14,16) disposed in axial spaced relation, each side plate having a plurality of apertures (26,28) with the apertures in one of the side plates in axial alignment with the apertures in the other of the side plates; a plurality of spindles (24,24a) having a constant diameter body portion, and locating flat means (44,46) formed in a segmental space (42) in one end of the body portion; a locating surface (40,40a) on the one side plate coaxial with and adjacent each aperture in the one side plate and extending radially therefrom; the spindles being disposed respectively in each pair of the apertures; a pinion gear (22) rotatably supported on each of the spindles; and a retaining ring (58) secured in the one side plate; characterised in that the apertures (26,28) are of substantially equal constant diameter; in that each spindle (24,24a) has shoulder means (36,62) adjacent the one end of the body portion with the shoulder means being in abutment with the locating surface (40,40a); by a retainer plate (54) having alignment surface means (56) disposed adjacent and radially outward from the locating flat means on each of the spindles for cooperating therewith to prevent rotation of the spindles in the apertures; in that the retaining ring (58) is in axial abutment with the retainer plate and cooperating therewith to prevent axial movement of the spindles in one axial direction; and in that the shoulder means cooperates with the locating surface to prevent axial movement of the spindles in an opposite axial direction. A planet carrier assembly as claimed in claim 1, wherein the locating flat means comprises a longitudinally extending flat surface (44) and a radially extending flat surface (46), the alignment surface means (56) being disposed adjacent and radially outward from the longitudinally extending flat surface on each of the spindles (24,24a). A planet carrier assembly as claimed in claim 1 or claim 2, wherein the shoulder means comprises a shoulder (36) adjacent the one end of the body portion of each spindle (24), the shoulder having a side wall (38) cooperating with the locating surface (40). A planet carrier assembly as claimed in claim 1 or claim 2, wherein the shoulder means comprises a locking ring (62) positioned in a groove (60) adjacent the one end of the body portion of each spindle (24a), the locking ring cooperating with the locating surface (40a).

Inventors: FUEHRER, REECE R.
Applicants: GENERAL MOTORS CORPORATION
Application year: 1991
Main classification: F16H57
IPC codes: F16H57