Abstract:
A gasket for a motor vehicle transmission includes an outer band that defines an inner open region. The outer band includes an enlarged portion where a baffle is located. The baffle prevents or minimizes the escape of hydraulic fluid from the transmission during the operation of the transmission.

Description:
FIELD 
     The present disclosure relates to a gasket. More specifically, the present disclosure relates to a baffled gasket for a transmission. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     A typical manual transmission for a motor vehicle includes a shift tower mounted on a housing of the transmission, and the shift tower is coupled to a shift assembly that is operated by a driver residing in the motor vehicle. When the driver makes a gear selection by transmitting motion to a shift lever associated with the shift assembly, the movement of the shift lever is transmitted to the shift tower, resulting in a gear change. During the operation of the transmission, hydraulic fluid is circulated within the transmission to dissipate heat and to lubricate the components. In certain arrangements, a vent is associated with the shift tower to compensate for the thermal expansion of air inside the transmission housing. In such arrangements, hydraulic fluid may be expelled through the vent during the operation of the transmission. 
     Hence there is a need for an improved venting process associated with a transmission shift tower. 
     SUMMARY 
     A gasket for a motor vehicle transmission includes an outer band that defines an inner open region. The outer band includes an enlarged portion where a baffle is located. The baffle prevents or minimizes the escape of hydraulic fluid from the transmission during the operation of the transmission. 
     In particular arrangements, the gasket both seals against leakage from a transmission housing and prevents splashing hydraulic fluid within the transmission housing from leaking out of a vent. 
     Further features, 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. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings: 
         FIG. 1  is a partial expanded view of a transmission shift tower assembly with a gasket in accordance with the present invention; 
         FIG. 2  is a perspective view of the gasket shown in  FIG. 1 ; and 
         FIG. 3  is a closeup view of the gasket positioned in the transmission shift tower assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Referring now to the drawings, a shift tower assembly embodying the principles of the present invention is illustrated in  FIG. 1  and designated at  10 . The shift tower assembly  10  includes a tower housing  14  with a generally flat plate  20  that is positioned on a transmission housing  12  of a manual transmission for a motor vehicle. A gasket  16  is positioned between the plate  20  and the tower housing  14  to form a seal, which prevents leakage of hydraulic fluid, such as oil, from the transmission. The plate  20  can be attached to the transmission housing  12  by one or more fasteners, such as, for example, threaded fasteners  22 , which extend through one or more openings  24  of the gasket  16  and are threaded into a set of threaded holes  26 . A shaft  18  extends through the tower housing  14  and into the transmission housing  12 . The shaft  18  is supported by the tower housing. It connects the gear shift lever into the passenger compartment and the internal selection and engagement systems. 
     When a shift change is selected, a driver moves the gear shift lever which is coupled to the shaft  18  with, for example, one or more cables. In turn, the shaft  18  pivots which results in a desired gear selection of a set of gears within the transmission housing  12 . 
     During the operation of the transmission, heat is generated within the transmission housing  12 . To maintain a suitable, low operating temperature, the generated heat is removed by circulating a heat transfer medium, such as hydraulic fluid, around the components in the transmission housing  12 . The hydraulic fluid can be pressurized or unpressurized (as in the present illustrated arrangement) and may be, as indicated above, some type of oil. As the hydraulic fluid within in the transmission housing  12  is circulated to dissipate heat and to lubricate the various components within the transmission, expanded heated air is pushed into a minor chamber  30  within the transmission housing  12  which has an opening  32 . The opening  32  communicates with a vent  33  in the plate  20 . As such, heat, as well as pressure buildup, within the transmission can be dissipated through the vent  32 . 
     In accordance with the principles of the present invention, the gasket  16  includes a baffle  28  that allows heat and pressure to dissipate through the vent  33  but prevents hydraulic fluid from splashing out of the vent  33  as the hydraulic fluid is being circulated within the transmission housing  12 . Turing to  FIG. 2 , the gasket  16  includes an outer band  34  which defines an inner opening  36  through which the shaft  18  extends. The openings  24  which facilitate securing the plate  20 , the gasket  16  and the transmission housing  12  together are distributed along the band  34 . The band  34  also includes an enlarged portion  35  in which the baffle  28  is located. The baffle  28  includes a flap portion  37  connected to the enlarge portion  35  of the band  34  along a segment  38 . The flap portion  37  is shaped such that a gap  40  is defined between the flap portion  37  and the enlarged portion  35 . Specifically, the gap  40  extends along the outer perimeter of the flap portion  37  that is not connected to the enlarged portion  35  as shown in  FIG. 2 . 
     Referring to  FIG. 3 , as the transmission is in operation, heat and/or pressure buildup can be dissipated from the vent  33  through the opening  32  and the gap  40 , since the gap  40  provides a path from the opening  32  to the vent  33 . The gap  40 , however, is narrow enough and positioned in such way to prevent or minimize hydraulic fluid from escaping past the flap portion  37  through the vent  33 . As the hydraulic fluid (as indicated by a splash pattern  41 ) is being circulated within the transmission housing  12 , some of the hydraulic fluid enters into a channel  43  that communicates with the chamber  30 . Without the use of the baffle  28 , some of the hydraulic fluid enters into the vent  33  through openings  44 . The hydraulic fluid is then pushed through a bore  46  and out of exit openings  48 . The fluid pattern into the vent  33  when the baffle  28  is not employed is indicated by the arrows  50 , indicating leakage of the hydraulic fluid through the openings  48  of the vent  33 . 
     When the vent  33  is assembled onto the plate  20 , it slightly moves the flap portion  37  (as indicated by the arrow  29 ), which bends along the segment  38  in such a manner that it deflects the hydraulic fluid directly into the chamber  30  and from entering into the openings  44  of the vent  33 , as indicated by the arrows  42 . Hence, the baffle  28  is able to keep the hydraulic fluid within the transmission housing  12  during the operation of the transmission. 
     In various arrangements, the gasket  16  can be made of a fibrous material, such as, for example, paper, or any other suitable material. A knife with the desired contours of the gasket  16  can be employed to form the gasket  16 . One of more gaskets  16  can be made with such a knife in a manufacturing operation, such as, for example, a stamping operation. The thickness of the gasket in various arrangements is between about 0.4 mm and about 0.8 mm. Further, in various arrangements, the gap  40  is about 2 mm. 
     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.