Abstract:
A low mass, two piece planetary gear carrier having an integrated clutch housing comprises a first carrier flange and clutch housing and a second carrier flange which are secured together by a plurality of threaded fasteners extending through hollow dowels. A plurality of planet gears receive needle bearing assemblies which are, in turn, supported on pins or stub shafts. The stub shafts are retained in the carrier by transverse retaining pins received in the second carrier flange and extending into the shafts. Unitized washers are disposed between both faces of the planet gears and the flanges. The method of assembly is also a feature of the present invention.

Description:
FIELD 
     The present disclosure relates to planetary gear assemblies for use in automatic motor vehicle transmissions and more particularly to a low mass, two piece planetary gear carrier having an integrated clutch housing. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     Planetary gear assemblies used in automatic motor vehicle transmissions are subject to numerous fabrication, assembly and operational constraints. Because it is the largest and heaviest member of the planetary gear assembly and because it receives and supports the planet gears, this is particularly true of the planet gear carrier. 
     Because of it size, it is always desirable to minimize its weight and thus to reduce its inertia as an energy saving consideration. Such weight reductions are, of course, limited to reductions which do not compromise the strength and durability of the carrier. Because the planet gears reside within the carrier, consideration must be given to how these gears as well as shafts, bearings and washers will not only be accommodated but also installed within the carrier. Finally, there is the issue of lubrication: consideration must be given to ensuring proper lubrication flow to the shafts and planet gears by incorporating appropriate fluid passageways. Such passageways must be capable of providing lubricating fluid not only when the carrier is rotating but also when it is stationary and the planet gears are rotating. 
     SUMMARY 
     The present invention provides a low mass two piece planetary gear carrier having an integrated clutch housing. The planetary gear carrier comprises a first carrier flange and clutch housing and a second carrier flange which are bolted together by a plurality of threaded fasteners extending through hollow dowels. A plurality of planet gears receive needle bearing assemblies which are, in turn, supported on pins or stub shafts. The stub shafts are retained in the gear carrier by transverse retaining pins received in the second carrier flange and extending into the shafts. Unitized washers are disposed between both faces of the planet gears and the flanges. The method of assembly is also a feature of the present invention. 
     Thus it is an aspect of the present invention to provide a low mass planetary gear assembly. 
     It is a further aspect of the present invention to provide a low mass, two piece planetary gear assembly. 
     It is a still further aspect of the present invention to provide a low mass planetary gear carrier. 
     It is a still further aspect of the present invention to provide a low mass, two piece planetary gear carrier. 
     It is a still further aspect of the present invention to provide a low mass planetary gear carrier having an integrated clutch housing. 
     It is a still further aspect of the present invention to provide a low mass, two piece planetary gear carrier having an integrated clutch housing. 
     It is a still further aspect of the present invention to provide a low mass planetary gear carrier having a first carrier flange and clutch housing and a second carrier flange which are secured together. 
     It is a still further aspect of the present invention to provide a low mass planetary gear carrier a first carrier flange and clutch housing and a second carrier flange which are secured together by a plurality of threaded fasteners. 
     It is a still further aspect of the present invention to provide a low mass planetary gear carrier a first carrier flange and clutch housing and a second carrier flange which are secured together by a plurality of threaded fasteners extending through hollow dowels. 
     Further aspects, advantages and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a fragmentary, sectional view of a portion of a transmission incorporating the present invention taken through a pinion gear, bearing and stub shaft; 
         FIG. 2  is a half sectional view of a planetary gear carrier having an integrated clutch housing according to the present invention taken through a threaded fastener and hollow dowel; 
         FIG. 3  is an exploded view of a planetary gear carrier having an integrated clutch housing according to the present invention from a first perspective; and 
         FIG. 4  is an exploded view of a planetary gear carrier having an integrated clutch housing according to the present invention from a second perspective. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     With reference to  FIG. 1 , a portion of an automatic motor vehicle transmission incorporating the present invention is illustrated and generally designated by the reference number  10 . The automatic transmission  10  includes a first or main, center axis shaft or quill  12  about which many components of the transmission  10  are co-axially or concentrically arrayed. For example, a second co-axial drive member  14  is coupled by interengaging spines  16  to the first or main shaft or quill  12 , a third quill or tubular drive member  20  is co-axially disposed about the first or main shaft or quill  12 , a fourth co-axial multiple component quill or tubular drive member  22  is disposed about the third quill or tubular drive member  20  and the first or main shaft for quill  12  and a fifth co-axial quill or drive member  24  is coupled to the components of the fourth quill or tubular drive member  22  by interengaging splines  26 . The transmission  10  also include a plurality of thrust bearings  28  that axially position and rotationally isolate the just recited components and radially extending members coupled thereto according to conventional practice. 
     A planetary gear assembly  30  having an integrated clutch housing according to the present invention resides in the automatic transmission  10 . The planetary gear assembly  30  includes a sun gear  32  which is coupled to a radially extending drive disc or plate  34  by an interengaging spline set  36 . The sun gear  32  is freely rotatably supported on a needle bearing assembly  38  on the fifth quill or drive member  24 . The planetary gear assembly  30  includes a first carrier flange and clutch housing  40  and a second carrier flange  60 . The first carrier flange and clutch housing  40  includes a plurality of apertures or openings  42  (one of which is illustrated in  FIG. 1 ) for receiving a like plurality of pins or stub shafts  44  (one of which is illustrated in  FIG. 1 ) and an axially extending outer flange  46  carrying or defining a plurality of female splines  48 . 
     Referring now to  FIGS. 1 and 2 , the first carrier flange and clutch housing  40  also includes a plurality of double counterbored openings  52  which receive a like plurality of threaded fasteners  54  and a portion of each of a pair of hollow dowels  56 . The second carrier flange  60  likewise includes a plurality of apertures or openings  62  which are sized and arranged as the apertures or openings  42  in the first carrier flange and clutch housing  40  and receive the pins or stub shafts  44 . The second carrier flange  60  also includes a plurality of radial apertures  64  which intersect each of the apertures or openings  62 . The second carrier flange  60  further includes a plurality of counterbored and threaded openings  66  which receive a portion of the hollow dowels  56  and the threaded fasteners  54 . The second carrier flange  60  also includes a plurality of female splines  68  disposed about a center or inner flange  70 . The female splines  68  engage male splines  72  on the fifth quill or drive member  24 . 
     Referring again to  FIG. 1 , disposed on each of the pins or stub shafts  44  is a needle bearing assembly  74  (one of which is illustrated in  FIG. 1 ) which freely rotatably supports a respective planet gear  76  (one of which is illustrated in  FIG. 1 ). Each of the planet gears  76  is in constant mesh with the sun gear  32  and a ring gear  80 . The ring gear  80  may be supported by and coupled to, for example, other components such as a ring gear  82  of an adjacent planetary gear assembly  84  and may include male splines  86  which engage a first plurality of friction plates or discs  88  of a friction clutch assembly  90 . The friction clutch assembly  90  also includes a second plurality of friction plates or discs  92  interleaved with the first plurality of friction plates or discs  88  which engages the female splines  48  on the first carrier flange and clutch housing  40 . 
     The planetary gear assembly  30  according to the present invention also includes features and aspects which ensure good and sufficient lubrication under all operating conditions. As illustrated in  FIG. 1 , the first or main shaft or quill  12  is preferably hollow and is pressurized with hydraulic (transmission) fluid from a pump (not illustrated). Radial passageways  94 A in the various shafts or quills  12 ,  14 ,  20  and  22  and oblique passageways  94 B in the quill  24  and the second carrier flange  60  provide lubricating fluid directly to the sun gear  32  and to each of the pins or stub shafts  44  supporting the needle bearing assemblies  74  and the planet gears  76 . 
     In order to ensure transfer of the lubricating fluid from the fifth quill or drive member  24  to the center or inner flange  70  of the second carrier flange  60  (and on to the planet gears  76 ) and particularly across the male splines  72  and the female splines  68 , at least one female spline  68  in the region  68 A of the lubricating passages  94 B is omitted, as illustrated in  FIGS. 3 and 4 , and the region is filled in with a wide, solid male spline  72  complementary to the region  68 A such that there is a small clearance between the outside diameters of the splines  68  and  72 . This major diameter fit of the splines  68  and  72  provides sufficient sealing to properly direct the lubricating fluid across the splines  68  and  72 , even when the first and second carrier flanges  40  and  60  are stationary. 
     Referring now to  FIGS. 1 ,  3  and  4 , additional components of the planetary gear assembly  30  according to the present invention and the steps involved in its assembly will now be set forth. After fabrication of the first carrier flange and clutch housing  40  and the second carrier flange  60  which are preferably die cast from aluminum to reduce mass and inertia whereby the female splines  48  are net formed, the hollow dowels  56  are pressed into the counterbored and threaded openings  66 . Next, the pins or stub shafts  44  are installed in the apertures or openings  62  of the second carrier flange  60  and a retaining pin  96  is installed in each of the radial apertures  64  and through a complementary aperture  98  in each of the pins or stub shafts  44 . To retain the retaining pins  96  in the stub shafts  44  and thereby retain the stub shafts  44  in the second carrier flange  60 , the ends of the stub shafts  44  proximate the retaining pins  96  are upset or swaged as indicated by the reference number  100 . 
     Next, unitized washers  102 , that is, washer assemblies that include two or four washers  104  coupled or connected by bands or strips of material  106  from which the washers  104  are fabricated which thereby simultaneously locate and install all of the washers  104  in one operation are first placed on the second carrier flange over the pins or stub shafts  44 . Then, the needle bearing assemblies  74 , the planet gears  76  and another unitized washer  102  are installed. Next, the first carrier flange and clutch housing  40  is engaged with the stub shafts  44  and the hollow dowels  56 . The hollow dowels  56  are a tight clearance fit within the counterbored openings  52  and  66  and thus ensure accurate alignment and registration between the first carrier flange and clutch housing  40  and the second carrier flange  60  as they are assembled. Last of all, the threaded fasteners  54  are installed in the counterbored openings  52  and tightened down. 
     The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.