Abstract:
An assembly including an input including first, second, third and fourth passages, a shaft surrounding the input, a housing including a hub surrounding the shaft, a first path connecting the first passage to a first servo cylinder, a second path connecting the second passage to a second servo cylinder, a third path connecting the third passage to balance volumes, and a fourth path connecting the fourth passage to a third servo cylinder, bypassing the hub.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to an apparatus for an independent, rotating, multi-clutch assembly having no fixed connection to a component of a gearset. 
     2. Description of the Prior Art 
     The kinematic arrangement of automatic transmissions, certain control elements, such as hydraulically-actuated clutches, have no fixed connection to any other transmission lever component. 
     In such cases, a need exists for a technique that simplifies the feed circuit to those clutches, i.e. pressure feeds for each of three clutch-apply circuits and a lube circuit that supplies three balance dams. 
     In the kinematic arrangement of the subject automatic transmission, three clutches have no fixed connection to any other transmission lever components. Instead of locating the clutches such that their servo cylinders are enclosed in one large clutch housing, multiple options regarding the location of at least one of the servo cylinders provides means for optimizing the clutch module. 
     SUMMARY OF THE INVENTION 
     An assembly including an input including first, second, third and fourth passages, a shaft surrounding the input, a housing including a hub surrounding the shaft, a first path connecting the first passage to a first servo cylinder, a second path connecting the second passage to a second servo cylinder, a third path connecting the third passage to balance volumes, and a fourth path connecting the fourth passage to a third servo cylinder, bypassing the hub. 
     Three clutches are integrated into a rotating clutch housing, which includes four feed circuits. A lube circuit supplies three clutch balance dams. A clutch-apply circuit communicates with each of the clutches. 
     Changing the location of the pistons reduces the total number of seals required. Separating the clutch pistons reduces the number and size of the rotating seals, thereby potentially improving fuel economy. 
     The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which: 
         FIG. 1  is a schematic diagram of the kinematic assembly for a motor vehicle automatic transmission; 
         FIG. 2  is a cross section of the kinematic assembly of  FIG. 1 ; 
         FIG. 3  is a schematic diagram of the clutch housing of the kinematic assembly and an arrangement of related clutch oil feed paths; 
         FIG. 4  is an end view of the input shaft showing axial, fluid passages in the shaft; 
         FIG. 5  is a schematic diagram of the clutch housing of the kinematic assembly and an alternate arrangement of related clutch oil feed paths; 
         FIG. 6  is a schematic diagram of a clutch housing of the kinematic assembly and another arrangement of related clutch oil feed paths; and 
         FIG. 7  is a schematic diagram of a clutch housing of the kinematic assembly and another arrangement of related clutch oil feed paths. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The assembly  10   FIG. 1  includes an input  12 ; output  14 ; intermediate shaft  16 ; a first planetary gear set  20  having a first sun gear  22 , a first ring gear  24 , a first carrier  26 ; and a set of planet pinions  30  supported on carrier  26  and in continuous meshing engagement with the sun gear  22  and the ring gear  24 . 
     A second planetary gear set  32  includes a second sun gear  34  fixedly coupled to sun gear  22 ; a second ring gear  36 ; a second carrier  38  fixedly coupled to the input  12 ; and a set of planet pinions  40  in supported on carrier  38  and in continuous meshing engagement with sun gear  34  and ring gear  36 . 
     A third planetary gear set  42  includes a third sun gear  44  fixedly coupled to ring gear  36 ; a third ring gear  46 ; a third carrier  48 ; and a set of planet pinions  50  supported on carrier  48  and in continuous meshing engagement with sun gear  44  and ring gear  46 . 
     A fourth planetary gear set  52  includes a fourth sun gear  54  fixedly coupled to ring gear  46 ; a fourth ring gear  56  fixedly coupled by a shell  58  to carrier  26 ; a fourth carrier  60  fixedly coupled to output  14 ; and a set of planet gears  62  supported on carrier  60  and in continuous meshing engagement with sun gear  54  and ring gear  56 . 
     A first brake  64  selectively holds ring gear  24  against rotation. 
     A second brake  66  selectively holds sun gears  22 ,  34  against rotation on the transmission case  124 . 
     A first clutch  68  selectively couples ring gear  36  to a clutch housing  70  rotation also on the transmission case  124 . 
     A second clutch  72  selectively couples carrier  48  to clutch housing  70 . 
     A third clutch  74  selectively couples ring gear  46  and sun gear  54  to input  12 . 
     A fourth clutch  76  selectively couples shell  58  to clutch housing  70 . 
       FIG. 2  shows that carrier  26  is secured to shell  58 . Clutch housing  70  includes an axial arm  82  formed with internal spine teeth, to which external teeth on the spacer plates  84  of clutch  68  are fixed for rotation with clutch housing  70 . The friction plates of clutch  68  are splined to external spline teeth formed on a ring  85 , which is formed with ring gear  36 . 
     Intermediate shaft  16 , which extends along axis  86  on the radial outer side of input  12 , is secured to ring  85  where a snap ring  88  completes the connection. Clutch housing  70  is supported by axially spaced bushings  90 ,  92  on the radial outer surface of intermediate shaft  16 . 
     Clutch housing  70  includes another axial arm  94  formed with external spine teeth, to which internal teeth on the spacer plates  96  of clutch  76  are fixed for rotation with clutch housing  70 . The friction plates of clutch  76  are splined to internal spline teeth formed on shell  58 . 
     External teeth  98  on the spacer plates of clutch  72  engage internal spline teeth formed on arm  94  of the clutch housing  70 . The friction plates of clutch  72  are splined to external spline teeth formed on carrier  48 . 
     Located between bushings  90 ,  92  and formed in the hub  100  of clutch housing  70  are four feed circuits. A single lube circuit supplies automatic transmission fluid (ATF) to the pressure balance volumes  102 ,  104 ,  106  of clutches  68 ,  72  and  76 . Balance dams  103 ,  105 ,  107  seal the pressure balance volumes  102 ,  104 ,  106  at the pistons  110 ,  112 ,  114  of the clutches  68 ,  72 ,  76 . 
     Each of the servo cylinders  69 ,  73 ,  77  of clutches  68 ,  72 ,  76  is supplied with actuating, clutch-apply pressure through individual circuits formed in the clutch housing  70 . When no actuating pressure is applied to clutches  68 ,  72 ,  76 , the clutch housing  70  has no fixed connection to any other component of assembly  10 . 
       FIG. 3  shows schematically the arrangement of  FIG. 2 , in which all of the three clutch pistons  110 ,  112 ,  114  and balance dams  103 ,  105 ,  107  are located in clutch housing  70 . 
     Four axial passages are formed in input shaft. Each of three of the passages carry fluid at clutch-apply pressure to a respective servo cylinder  69 ,  73 ,  77  from the input shaft  12 , through intermediate shaft  16  and into the clutch housing  70 . Similarly the third input shaft passage carries lube to the balance volumes  102 ,  104 ,  106  from the input shaft  12 , through intermediate shaft  16  and into the clutch housing  70 . 
     In the arrangement of  FIG. 3 , clutch complexity is associated with the clutch housing  70  since all three sets of balance dams  103 ,  105 ,  107 , clutch friction plates and clutch spacer plates are assembled together as one unit. Clutch  68  releaseably connects clutch housing  70  to ring gear  36 . Clutch  72  clutch releaseably connects the clutch housing  70  to carrier  48 . Clutch  76  releaseably connects clutch housing  70  to carrier  26  and ring gear  56  though shell  58 . 
       FIG. 4  shows the arrangement of axial, fluid passages  120 ,  121 ,  122 , and  123  and local, radial passages in the input shaft  12 , which is centered at axis  86 . Each radial passage connects one of the axial passages to one of the corresponding clutches  68 ,  72 ,  76 . 
       FIG. 5  shows schematically a kinematic arrangement, in which two of the clutch pistons  110 ,  114  and two of the balance dams  103 , 107  are located in clutch housing  70 . The piston  112 , balance volume  104  and balance dam  105  of clutch  72  are located in the planetary carrier  48 ′. 
     ATF at clutch-apply pressure is supplied to servo cylinders  69 ,  77 , and lube is supplied to balance volumes  102 ,  106  from input shaft  12  through intermediate shaft  16  into clutch housing  70 . ATF at clutch-apply pressure is supplied to servo cylinder  73  directly from input shaft  12  to the right-hand side of carrier  48 ′ and leftward either through an axial passage is planet pinions  50 ′ or through an axial passage in carrier  48 ′. 
       FIG. 6  shows schematically an alternate kinematic arrangement to that of  FIG. 4 , clutch feed oil and balance oil are fed into the left-hand side of carrier  48  from the input shaft  12  through intermediate shaft  16 . 
     In the arrangement of  FIG. 5  oil is fed to clutch  72  through only 1 set of seals, i.e., seals for oil flowing from input shaft  12  to carrier  48 , whereas in  FIGS. 3 and 6  two sets of seals are required, one set for oil from input shaft  12  to intermediate shaft  16 , and a second set of seals for oil flowing from intermediated shaft  16  to the hub  100  of clutch housing  70 . 
     In the arrangements of  FIGS. 5 and 6 , clutch  68  releaseably connects clutch housing  70  to ring gear  36 . Clutch  72  clutch releaseably connects clutch housing  70  to carrier  48 ,  48 ′. Clutch  76  releaseably connects clutch housing  70  to carrier  26  and ring gear  56  though shell  58 . 
       FIG. 7  shows schematically a kinematic arrangement, in which two of the clutch pistons  112 ,  114  and two of the balance dams  105 , 107  are located in clutch housing  70 . The piston  110 , balance volume  102  and balance dam  103  of clutch  68  are located in the intermediate shaft  16 , which connects ring gear  84  and sun gear  44 . 
     For clutches  72  and  76 , oil is fed from input shaft  12  through the intermediate shaft  16  into the clutch housing  70 . For clutch  68 , clutch feed oil and balance volume oil are fed into the intermediate shaft  16  directly from the input shaft  12 . 
     In the arrangement of  FIG. 6 , lube oil is supplied to balance volume  102  and oil at clutch-apply pressure is supplied to servo cylinder  69  for clutch  68  through only one set of seals, i.e., seals for oil flowing from input shaft  12  to intermediate shaft  16 . Clutch  68  releaseably connects clutch housing  70  to ring gear  36 . Clutch  72  clutch releaseably connects clutch housing  70  to carrier  48 . Clutch  76  releaseably connects clutch housing  70  to carrier  26  and ring gear  56  though shell  58 . 
     In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described.