Abstract:
A transmission lubrication assembly includes a stator tube having a fluid passage and a sleeve bore, and a stator tube sleeve having a lubrication path provided along an external peripheral service thereof. In another aspect, the transmission lubrication assembly may include a solid input shaft rotatably received within the stator tube, a valve body, and a lubrication tube that provides fluid communication between the fluid passage and the valve body. In yet another aspect, a method of lubricating a transmission assembly includes providing a pressurized source of lubricating fluid, providing a stator tube comprising a fluid passage, and directing a portion of the lubricating fluid to a section of the transmission assembly by way of a stator tube sleeve, wherein the stator tube sleeve has an axial channel through which the lubricating fluid flows.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Aspects of the present invention relate to transmission lubrication and, in particular, to an assembly, and related systems and methods for externally providing lubrication to various internal components of a transmission. 
     2. Background of the Technology 
     A transmission is a device for transmitting the power generated by an engine, typically via a drive shaft connected to drive wheels on a vehicle. A conventional transmission provides for a variety of forward gears, as well as a neutral and a reverse gear. The typical components of an automatic transmission include a torque converter to allow a vehicle to stop while still in gear and with the engine running, a hydraulic system that pumps pressurized fluid through a valve body for controlling the planetary gear set through a series of clutches and bands, one or more planetary gear sets for providing the various gears, a governor to monitor speed and control shifting, and an oiling system for lubricating the many moving parts of the transmission assembly. A transmission housing or transmission case is also provided to protect and properly seal the various components internal thereto. 
       FIGS. 1-3  illustrate various aspects of a transmission assembly of the related art. For example,  FIG. 1  illustrates an end view of an input shaft section  10  of a conventional transmission assembly, wherein an input shaft  20  is rotatably fitted with planetary gears  30  and a stator tube  40 . 
       FIG. 2  is a partial sectional view of the input shaft section  10  taken along line C-C of  FIG. 1 , and generally depicts additional aspects of a related art transmission, including a high gear clutch and drum assembly  50 , planetary section  60 , a planetary output shaft  70 , which may be integrally connected to the planetary section  60 , a governor support  80 , and a transmission case  90 . As shown in  FIG. 2 , the stator tube  40  may comprise an elongated cylindrical tube portion  42  concentrically arranged around a forward portion of the input shaft  20 , a flanged section  44 , and a cylindrical hub section  46 . The cylindrical hub section  46  may be formed with a sleeve bore  45  axially extending into the hub section  46  from a distal end  47  of the stator tube  40 , the sleeve bore  45  having a larger inner diameter than an inner diameter of the tube portion  42 . A stator tube sleeve  48  may be concentrically positioned around an outer surface of the input shaft  20  inside the sleeve bore  45 . The stator tube sleeve  48  is configured with an inner diameter to minimize clearance between the stator tube sleeve  48  and the input shaft  20  while permitting free rotation of the input shaft  20  during operation of the transmission. The cylindrical hub section  46  may be formed with hub annulets  49  on an outer peripheral surface to provide seats for sealing rings, for example. The planetary gears  30  and the planetary section  60  may be coupled to an end portion of the input shaft  20 , for example. 
     In the transmission of the related art shown in  FIGS. 1-3 , the interior components of the transmission receive a lubricating fluid, such as transmission oil, through a fluid passage  100 . The fluid passage  100  may be cross-drilled, for example, into the flanged section  44  of the stator tube  40 . The fluid passage  100  allows the pressurized lubrication fluid to flow radially inward toward the stator tube sleeve  48 . As shown in  FIG. 3 , which is an enlarged view of the detail Section D, shown in dashed circle in  FIG. 2 , the stator tube sleeve  48  may comprise features, such as channels, grooves, protrusions, and/or through-holes, to direct and control the communication of lubricating fluid to particular areas or components of the transmission. 
     For example, as shown in  FIGS. 2 and 3 , the lubricating fluid communicates with the stator tube sleeve  48  by way of the fluid passage  100 . As shown in  FIG. 3 , the stator tube sleeve  48  is formed and/or arranged so as to provide a gap  110  between the inner peripheral surface of the stator tube  40  and an outer peripheral surface of the stator tube sleeve  48 . As the lubricating fluid travels through the gap  110 , a channel  115  draws off some of the pressurized fluid to lubricate the components of the high gear clutch and drum assembly  50 , for example, while the remaining fluid is forced through an opening  120  in the stator tube sleeve  48  and into an annular chamber  125 . 
     As shown in  FIG. 2 , a transverse fluid passage  130  is provided that extends radially inward from the outer surface of the input shaft  20  and provides fluid communication between the annular chamber  125  and a central fluid passage  135 . The central fluid passage  135  extends through the center of the input shaft  20  from a point at or near the transverse fluid passage  130  to an outlet  140  (see also  FIG. 1 ) at one end of the input shaft  20 . Lubrication openings  145  are provided at predetermined locations along the length of the input shaft  20  and extend radially from the central fluid passage  135  to the outer surface of the input shaft  20  to provide fluid communication between the central fluid passage  135  and the areas of the transmission containing the planetary gears  30 , for example, and various other internal components, such as reverse clutches, washers, and rear case bushings and/or bearings. Thus, the pressurized fluid in the annular chamber  125  is forced through the transverse fluid passage  130  and into the central fluid passage  135 , from which the pressurized fluid exits through the lubrication holes  145  and the outlet  140 , to provide lubrication to the internal components of the transmission. 
     A shortcoming, among others, of the conventional transmission assembly of the related art described above is that the transmission lubrication system relies on internally feeding the lubricant (e.g., transmission fluid) to the various components through openings or passages in the shafts or components of the transmission. In particular, the many openings or passages in the input shaft  20  may significantly weaken the torque-bearing capability of the component and significantly introduce areas of substantial stress concentration, which may lead in turn to the eventual damage or failure of the input shaft  20 . 
     There is an unmet need in the art for a transmission lubrication system that effectively lubricates the internal components of a transmission assembly without the need to provide openings, passages, or other weakening features, in the input shaft of the transmission assembly. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention include features for lubricating a transmission assembly without having to provide openings or passages in the input shaft. 
     Among other things, aspects of the present invention enhance the performance of a transmission assembly by allowing for a solid input shaft capable of sustaining higher torque without failure, by, for example, eliminating weaknesses in the integrity of conventional transmissions produced by use of openings or passages in the input shaft for internally lubricating the components of the transmission assembly. 
     Exemplary features usable in accordance with aspects of the present invention include a transmission lubrication assembly that has a stator tube with a fluid passage, an input shaft rotatably received within the stator tube, a transmission case that has one or more lubrication conduits, and one or more lubrication tubes that provide fluid communication between the fluid passage(s) and the lubrication conduit(s). 
     In accordance with other aspects of the present invention, the transmission lubrication assembly may include a stator tube sleeve provided between the input shaft and the stator tube, wherein the stator tube sleeve forms a lubrication path that extends from the fluid passage to at least one end of the stator tube. 
     In accordance with aspects of the present invention, a method of lubricating a transmission assembly may include providing a pressurized source of lubricating fluid, providing a stator tube comprising a fluid passage, and directing a portion of the lubricating fluid to a section of the transmission assembly by way of a stator tube sleeve, wherein the stator tube sleeve has an axial channel through which the lubricating fluid flows. 
     Additional advantages and novel features of aspects of the invention will be set forth in part in the description that follows, and in part will become more apparent to those skilled in the art upon examination of the following or upon learning by practice thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       In the drawings: 
         FIG. 1  is an end view of an input shaft section of a transmission assembly of the related art; 
         FIG. 2  is a partial sectional view of the input shaft section of a transmission assembly of the related art taken along line C-C of  FIG. 1 ; 
         FIG. 3  is an enlarged view of the detail Section D, shown in dashed circle in  FIG. 2 ; 
         FIG. 4  is an end view of an input shaft section of a transmission assembly, in accordance with aspects of the present invention; 
         FIG. 5  is a partial sectional view of the input shaft section of a transmission assembly taken along line B-B of  FIG. 4 , in accordance with aspects of the present invention; 
         FIG. 6  is an enlarged view of the detail Section C, shown in dashed circle in  FIG. 5 ; and 
         FIG. 7  is a perspective view of an exemplary stator tube sleeve, in accordance with aspects of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description may include specific details for illustrating various aspects of a transmission lubrication assembly and related systems and methods. However, it will be apparent to those skilled in the art that aspects of the invention may be practiced without these specific details. In some instances, previously described or well known related elements may be shown in block diagram form, generally depicted, or omitted, to avoid obscuring aspects of the inventive concepts presented throughout this disclosure. 
     Various aspects of a transmission lubrication assembly, for example, may be illustrated by describing components that are coupled together. As used herein, the term “coupled” is used to indicate either a direct connection between two components or, where appropriate, an indirect connection of two components through intervening or intermediate components. In contrast, when a component is referred to as being “directly coupled” to another component, there are no intervening elements present. 
     Relative terms such as “lower” or “bottom” and “upper” or “top” may be used herein to describe one element&#39;s relationship to another element, from the perspective illustrated in the drawings. It will be understood that relative terms are intended to encompass different orientations of an apparatus in addition to the orientation depicted in the drawings. By way of example, if an apparatus in the drawings is turned over, elements described as being on the “bottom” side of the other elements would then be oriented on the “top” side of those other elements. The term “bottom” can therefore encompass both an orientation of “bottom” and “top” depending on the particular orientation of the apparatus. 
       FIG. 4  illustrates an end view of an input shaft section  210  for a transmission assembly, in accordance with aspects of the present invention. The input shaft section  210  includes an input shaft  220  that is fitted with a sun gear  230  and a flange gear  232  (see  FIG. 5 ), and a stator tube  240 . By comparison to the input shaft section  10  of the related art transmission assembly depicted in  FIG. 1 ,  FIG. 4  illustrates the lack of an outlet in the end of the input shaft  220 . Furthermore, in accordance with aspects of the present invention, a lubrication tube  350  may connect a lubrication passage  300  (see  FIGS. 5 and 6 ) provided in the stator tube  240  to a valve body  292  provided toward a rear portion of a transmission case  290 . 
     To further illustrate features in accordance with aspects of the present invention,  FIG. 5  provides a partial sectional view of the input shaft section  210  taken along line B-B of  FIG. 4 . Additional components of a transmission assembly are generally depicted, including a high gear clutch and drum assembly  250 , a planetary section  260 , which may include a ring gear, a planet carrier and planet gears for engaging the sun gear  230  and/or the flange gear  232  in a compound planetary gearset configuration, for example, a planetary output shaft  270 , which may be integrally connected to the planetary section  260 , a governor support  280 , a transmission case  290 , and a valve body  295 . As shown in  FIG. 5 , the stator tube  240  may comprise a conduit  242 , such as an elongated cylindrical tube portion, arranged around a forward portion of the input shaft  220 , a flanged section  244 , and a cylindrical hub section  246 . The cylindrical hub section  246  may be formed with a sleeve bore  245  axially extending into the hub section  246  from a distal end  247  of the stator tube  240 , the sleeve bore  245  having a larger inner diameter than an inner diameter of the conduit  242 . A stator tube sleeve  248  may be interference fit with the stator tube  240  to be concentrically positioned around an outer surface of the input shaft  220  inside the sleeve bore  245 . The stator tube sleeve  248  is positioned axially inside the sleeve bore  245  to abut a step  243  at the forward end of the sleeve bore  245 . The stator tube sleeve  248  may thus traverse an opening  301  of the lubrication passage  300  where the lubrication passage  300  opens into the sleeve bore  245 . 
     The cylindrical hub section  246  may be formed with hub annulets  249  on an outer peripheral surface to provide seats for sealing rings, for example. The sun gear  230 , flange gear  232 , and the planetary section  260  may be rotatably coupled to an end portion of the input shaft  220 , for example. 
     In the related art transmission shown in  FIGS. 1-3 , a lubricating fluid is forced through passages and holes in the input shaft  20  to lubricate the internal components of the transmission. As shown in  FIGS. 4-6 , the input shaft  220 , in accordance with aspects of the present invention, may be formed to be a completely solid shaft, for example, with no through-holes or internal passages, allowing for a significantly stronger shaft that can sustain greater torque without breaking, for example. The transmission lubrication assembly, in accordance with aspects of the present invention, maintains the necessary lubrication to the proper locations of the transmission through a stator tube sleeve  248  (in contrast to the sleeve  48  of the related art transmission assembly of  FIG. 3 ), and by redirecting a portion of the lubrication fluid from the lubrication passage  300 , through the lubrication tube  350 , and to the valve body  295 . 
     As shown in  FIG. 5 , automatic transmission fluid, for example, may be provided from a transmission cooler to a fluid passage  300 . The fluid passage  300  may be cross-drilled into the flanged section  244  of the stator tube  240 . The fluid passage  300  allows the fluid to flow (e.g., under pressure) radially inward toward the stator tube sleeve  248 . As the pressurized fluid enters the fluid passage  300 , for example, a portion of the lubrication fluid may be forced into the lubrication tube  350 . 
     As shown in  FIG. 6 , which is an enlarged view of the detail Section C, shown in dashed circle in  FIG. 5 , because the lubrication fluid is not fed through the interior of the input shaft  220 , the stator tube sleeve  248  may be formed to provide a lubrication path  310  between the inner peripheral surface of the stator tube  240  and an outer peripheral surface of the stator tube sleeve  248 . As shown in  FIG. 7 , the lubrication path  310  may comprise a channel provided in an external peripheral surface of the stator tube sleeve  248  and configured to extend the entire axial length of the stator tube sleeve  248 , for example, so that lubricating fluid may be expelled via one end of the hub section  246  of the stator tube  240 . As shown in  FIG. 6 , because the stator tube sleeve  248  traverses the opening  301  of the fluid passage  300 , pressurized lubricating fluid may be forced into the lubrication path  310 . In addition, one or more channels  315  may be provided that run radially through the hub section  246  of the stator tube  240 , for example. The pressurized fluid in the lubrication path  310  may thus be provided through the one or more channels  315  for lubricating the components, including bushings and high gear clutches, of the high gear clutch and drum assembly  250 , for example. 
     As shown in  FIG. 5 , in order to lubricate a rear portion of the transmission assembly, the lubrication tube  350  that draws lubrication fluid from the fluid entering passage  300  may be routed from the stator tube  240  external to the transmission case to communicate with the valve body  295 . In accordance with aspects of the present invention, an access port may be provided into the lubrication passage  300  by drilling a transverse hole through the flanged portion  244  of the stator tube  240 . Although described herein as a lubrication tube  350 , the lubrication tube  350  may include any suitable conduit or passageway that can provide fluid communication between the fluid passage  300  of the stator tube  240  to a different section of the transmission by access through the transmission case. 
     For example, as shown in  FIG. 5 , the valve body  295  may receive the lubrication fluid from the lubrication tube  350 . The valve body  295 , in turn, may transfer the lubrication fluid through an external end portion of the transmission case  290 . A lubrication passage may be provided into the planetary section  260  of the transmission from the valve body  295  by forming a conduit  292  through the transmission case  290  that radially aligns, for example, with a conduit  285  through the governor support  280 . An inlet  275  through the planetary output shaft  270  further communicates the fluid path into the interior of the transmission assembly. Thus, lubrication fluid provided through the lubrication tube  350  may be communicated (e.g., sprayed) onto the internal components of the transmission assembly, including the various planetary gears and other components, such as the reverse clutches, washers rear case bushings and/or bearings. In this manner, the rear internal components of the transmission assembly may be lubricated via the lubrication tube  350  without the need to provide a fluid path through the input shaft  220 . The integrity of the input shaft  220  may thus be greatly enhanced. 
     Example aspects of the present invention have now been described in accordance with the above advantages. It will be appreciated that these examples are merely illustrative of variations thereof. Many other variations and modifications will be apparent to those skilled in the art.