Abstract:
A system for supplying fluid to transmission control elements includes a body producing clutch-apply pressures and a lube source, clutches, each clutch including a servo and a balance volume, a shaft including passages, a support including paths communicating each of the clutch-apply pressures and the lube source to a respective passage, and a clutch hub communicating clutch-apply pressure from each of the passages to a respective servo, and communicating the lube source to the balance volumes.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates generally to an apparatus for supplying fluid to clutch and brake control elements of an automatic transmission and to a transmission lube circuit. 
         [0003]    2. Description of the Prior Art 
         [0004]    An automatic transmission for a motor vehicle capable of producing a large number of forward gear ratios may require several brakes and four or more clutches to control its operation. In addition such a transmission may require two or three passages of oil feed to its torque converter. 
         [0005]    A need exists in the industry for a technique that feeds automatic transmission fluid (ATF) to the torque converter, clutches, brakes and a lube circuit through a front support assembly such that the axial length of the transmission is minimized. The ATF must be supplied to a separate oil path for each clutch-apply circuit, the lube circuit and each of the torque converter circuits while providing sealing between the paths, adequate flow area, and connections from a hydraulic control body through the pump support. 
       SUMMARY OF THE INVENTION 
       [0006]    A system for supplying fluid to transmission control elements includes a body producing clutch-apply pressures and a lube source, clutches, each clutch including a servo and a balance volume, a shaft including passages, a support including paths communicating each of the clutch-apply pressures and the lube source to a respective passage, and a clutch hub communicating clutch-apply pressure from each of the passages to a respective servo, and communicating the lube source to the balance volumes. 
         [0007]    In conventional automatic transmissions having multiple rotating clutches and a three-passage torque converter, an extra support structure in the center of the trans (called a center support) is required to allow passage of one or more of the rotating clutches. This system provides feeds for all the clutches and the lube circuit without adding a center support. 
         [0008]    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 
         [0009]    The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which: 
           [0010]      FIG. 1  is a schematic diagram of the kinematic assembly of an automatic transmission for a motor vehicle; 
           [0011]      FIG. 2  is a cross sectional side view of an intermediate length portion of the kinematic assembly of  FIG. 1  showing a clutch housing; 
           [0012]      FIG. 3  is a cross sectional side view of a front length portion of the kinematic assembly of  FIG. 1  showing a brake assembly; 
           [0013]      FIG. 4  is a cross sectional side view of a length portion of the kinematic assembly of  FIG. 1  showing hydraulic passages; 
           [0014]      FIG. 5  is a cross sectional end view in the pump support showing hydraulic passages; and 
           [0015]      FIG. 6  is a cross sectional side view of a length portion of the kinematic assembly of  FIG. 1  showing hydraulic passages that supply the rear clutch. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    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 . 
         [0017]    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 . 
         [0018]    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 . 
         [0019]    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 . 
         [0020]    A first brake  64  selectively holds ring gear  24  against rotation. 
         [0021]    A second brake  66  selectively holds sun gears  22 ,  34  against rotation on the transmission case  124 . 
         [0022]    A first clutch  68  selectively couples ring gear  36  to a clutch housing  70 . 
         [0023]    A second clutch  72  selectively couples carrier  48  to clutch housing  70 . 
         [0024]    A third clutch  74  selectively couples ring gear  46  and sun gear  54  to input  12 . 
         [0025]    A fourth clutch  76  selectively couples shell  58  to clutch housing  70 . 
         [0026]      FIG. 2  shows that carrier  26  is secured to shell  58 . 
         [0027]    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 . 
         [0028]    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 . 
         [0029]    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 a shell  58 . 
         [0030]    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 . 
         [0031]    Located between bushings  90 ,  92  and formed in the hub  100  of clutch housing  70  are four feed circuits. A single balance oil feed supplies automatic transmission fluid (ATF) to the pressure balance volumes  102 ,  104 ,  106  of clutches  68 ,  72 ,  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 . 
         [0032]    Each of the servo cylinders  69 ,  73 ,  77  of clutches  68 ,  72 ,  76  is supplied with actuating 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 . 
         [0033]      FIG. 3  shows a pump support  120  secured by bolts  122  to the transmission case  124  and supporting the input shaft  12  on a bushing  126 . A hub  128  for brakes  64 ,  66  includes a radial arm  130 , secured to the pump support, and an axial arm formed with external and internal axial splines, to which the spacer plates of the brake and clutch are secured, respectively. 
         [0034]    The friction discs  132  of brake  66  are connected to external, axial spline teeth formed on a disc  134 , which is secured to the sun gears  22 ,  34  through intermediate shaft  18 . The friction discs  136  of brake  64  are connected to internal, axial spline teeth formed on a disc  138 , which is secured to ring gear  24  and is supported between two thrust bearings  140  located on the carrier  26 . 
         [0035]    The planet pinions  30  of gearset  20  are supported for rotation on a pinion shaft  142 , which is supported on carrier  26 . 
         [0036]    Pump support  120  is formed with a first cylinder  144  containing a piston  146 , which extends though openings  148  into contact with one of the spacer plates of brake  64 . Brake-apply pressure is carried through passages  150 ,  151  to cylinder  144 . The openings  148  in hub radial arm  130  allow an assembler of the brake hub assembly to see though the arm while aligning friction plates  136  with disc  138 . 
         [0037]    Pump support  120  is also formed with a second cylinder  154  containing a piston  156 , which contacts one of the spacer plates of brake  66 . Brake-apply pressure is carried through passage  158  to second cylinder  154 . 
         [0038]    The radial arm  130  of the brake hub  128  is secured to the transmission case  124  such that the arm contacts an axial stop  152 , which limits axial displacement of the arm and provides an axial reaction force to the force of piston  146  applied to the plates of brake  64  and the force of piston  156  applied to the plates of brake  66 . 
         [0039]      FIG. 4  shows a torque converter  198  enclosed by an impeller housing  160 ,  162 , which is driveably connected to an engine shaft or other power source. A drive  164  is driveably connected to impeller housing  160 . An idler gear  166 , supported on a bearing  168  and meshing with the drive gear, is driven by impeller housing  160  in rotation about axis  170 . A gear  172 , meshing with idler gear  166 , is connected by a spline to a rotor shaft  174 , which rotates about axis  176 . 
         [0040]    The rotor  178  of a variable displacement pump  180 , secured to the rotor shaft  174 , draws automatic transmission fluid (ATF) into the pump&#39;s inlet from an oil sump  182 , through a filter  184  located in the sump. ATF exiting the outlet of pump  180  flows sequentially through passage  186 , a hydraulic control body  188 , a series of oil feed paths  190  and a series of drilled oil feed holes  192 . The oil feed holes  192  are formed in transmission case  124 . 
         [0041]    The pump support  120  is formed with drilled oil feed paths directed toward axis  86  in the pump support  120 . Each oil feed path connects one of the drilled oil feed holes  192  with a corresponding oil feed channel  194 . Drilled holes in a torque converter stator shaft  196  connect each of the channels  194  to input shaft  12  and to the torque converter  198  located within housing  160 . 
         [0042]    Referring now to  FIGS. 4 and 5 , one of the oil feed holes  192  is connected by feed path  200  in pump support  120  to a feed channel  202 , through which the torque converter  198  is charged with ATF through passage  204 . 
         [0043]    Another one of the oil feed holes  192  is connected by feed path  206  in pump support  120  to a feed channel  208 , through which a torque converter lockup clutch is actuated through passage  210 . 
         [0044]    One of the oil feed holes  192  is connected by feed path  212  in pump support  120  to a feed channel  214 , through which the torque converter  198  is released. 
         [0045]      FIG. 5  shows the feed path  151  and passage  150 , through which brake  64  is actuated. 
         [0046]    One of the oil feed holes  192  is connected by feed path  216  in pump support  120  to passage  158 , through which brake  66  is actuated. 
         [0047]    One of the oil feed holes  192  is connected by feed path  218  in pump support  120  to a feed channel  220 , connected though an axial passage  222  in input shaft  12 , through which clutch  68  is actuated. 
         [0048]    One of the oil feed holes  192  is connected by feed path  224  in pump support  120  to a feed channel  226 , connected though an axial passage in input shaft  12 , through which clutch  72  is actuated. 
         [0049]    One of the oil feed holes  192  is connected by feed path  228  in pump support  120  to a feed channel  230 , connected though an axial passage in input shaft  12 , through which clutch  74  is actuated. 
         [0050]    One of oil feed holes  192  is connected by feed path  232  in pump support  120  to a feed channel  234 , connected though an axial passage in input shaft  12 , through which a lube circuit is supplied. The lube circuit carries ATF to the balance volumes of clutches  68 ,  72 ,  74 ,  76  through axial passage  262 , as shown in  FIG. 6 . 
         [0051]    Each of the four axial passages in input shaft  12 , through which clutches  68 ,  72 ,  74  are actuated and the lube circuit is supplied, is mutually parallel and parallel to axis  86 . 
         [0052]    Three of the axial passages in input shaft  12  communicate through clutch housing  70  to the servo cylinders of clutches  68 ,  72 ,  74  through oil feed paths in the clutch housing similar to those described with reference to the pump support  120  of  FIGS. 4 ,  5 . The axial lube passage in input shaft  12  also communicates through clutch housing  70  to the balance volumes  102 ,  104 , 106  of clutches  68 ,  72 ,  74  through oil feed paths in the clutch housing  70  similar to those described with reference to the pump support  120 . 
         [0053]      FIG. 2  shows the axial  240  and radial  242  passages, through which clutch-apply pressure is supplied to clutch  72 , and the axial  244  and radial  246  passages, through which lube is supplied to the balance volumes  102 ,  104 ,  106  of clutches  68 ,  72 ,  76 , respectively. 
         [0054]      FIG. 6  is a cross sectional side view of a rearward portion of the kinematic assembly of  FIG. 1  showing hydraulic passages that supply lube and clutch-apply pressure to clutch  74 . A passage  248  carries fluid from the control body  188 , through the oil sump  182  and transmission case  124 , to a radial passage  250  formed in the output shaft  14 . Aligned and connected axial passages  252 ,  254  in output shaft  14  and input shaft  12 , respectively, hydraulically connect passage  250  and radial passage  256 , which carries clutch-apply pressure to the cylinder  258  of the servo that actuates clutch  74 . 
         [0055]    The same lube passage  262  in input shaft  12  that carries lube to clutches  68 ,  72 ,  76  also carries ATF lube to clutch  74  from source of lube in control body  188 . Axial passage  262  in input shaft  12  is hydraulically connected to a radial passage  264 , which carries lube to the balance volume  266  of clutch  74 . 
         [0056]    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.