Abstract:
A sealing and drainage device for a motor vehicle transmission is located in a wall approximately near the bottom of the transmission housing and includes a ball and a plate that encloses the ball in a bore through the housing wall. The plate has an opening on which the ball sits under normal operating conditions. During unexpected flooding conditions, water flows through the opening into the bore. The ball floats on the water such that as the water rises in the bore, the ball rises as well to the top of the bore to seal the bore from the interior of the housing, preventing water from flowing into the housing.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/592,994, filed Jan. 31, 2012, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to a transmission for a motor vehicle. More specifically, the present disclosure relates to a sealing and drainage device for a transmission for a motor vehicle. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0004]    Transmissions for motor vehicles include components such as gears and clutch assemblies enclosed in a housing. In unexpected circumstances, the housing may be partially or fully submerged in water when the vehicle crosses over deep water, which may occur, for example, during flooding. In such situations, the housing is partially or fully submerged for a short period of time. Hence, to fully seal the interior of the housing from incoming water for a long period of time is uneconomical. 
         [0005]    Accordingly, there is a need for a sealing and drainage device for a transmission that prevents damage to the interior components of the transmission when the transmission housing is partially or fully submerged in water. 
       SUMMARY 
       [0006]    The present invention provides a sealing and drainage device for a motor vehicle transmission. The sealing and drainage device is located in a wall approximately near the bottom of the transmission housing and includes a ball and a plate that encloses the ball in a bore through the housing wall. The plate has an opening on which the ball sits during normal operating conditions. During unexpected flooding conditions, water flows through the opening into the bore. The ball floats on the water such that as the water rises in the bore, the ball rises as well to the top of the bore to seal the bore from the interior of the housing, preventing water from flowing into the housing. 
         [0007]    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 
         [0008]    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: 
           [0009]      FIG. 1  is cross-sectional view of a motor vehicle transmission shown a location for a sealing and drainage device in accordance with the principles of the present invention; 
           [0010]      FIG. 2A  is a cross-sectional view of an arrangement for a sealing and drainage device in accordance with the principles of the present invention; 
           [0011]      FIG. 2B  is a view along the line A-A of  FIG. 2A ; 
           [0012]      FIG. 3A  is a cross-sectional view of an alternative sealing and drainage device in accordance with the principles of the present invention; 
           [0013]      FIG. 3B  is a close-up view of a plunger for the sealing and drainage device shown in  FIG. 3A ; 
           [0014]      FIG. 4  is a close-up view of a plunger assembly for the sealing and drainage device of  FIG. 3A ; 
           [0015]      FIG. 5  is a close-up view of a plug for the plunger assembly shown in  FIG. 4 ; 
           [0016]      FIG. 6  is a cross-sectional view of yet another arrangement for a sealing and drainage device in accordance with the principles of the present invention; and 
           [0017]      FIG. 7  is a cross-sectional view of yet another arrangement for a sealing and drainage device in accordance with the principles of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0019]    Referring now to the drawings, a motor vehicle transmission embodying the principles of the present invention is illustrated in  FIG. 1  and designated at  10 . The transmission  10  includes a housing  11  enclosing a clutch assembly  21  and further includes a sealing and drainage device  31  at the bottom of the housing  11 . When the housing  11  is partially or fully submerged in water, for example, in an unexpected flooding condition, the sealing and drainage device  31  partially seals the housing  11  to prevent the level of water in the housing  11  from exceeding a maximum level  41  such that water does not damage the clutch assembly  21 . Once the flooding condition is eliminated, the sealing and drainage device  31  allows water to drain out of the housing  11 . 
         [0020]    Referring to  FIGS. 2A and 2B , the sealing and drainage device  31  includes a cylindrical bore  12  with a cone surface  13  machined into the housing  11 . The sealing and drainage device  31  further includes a light ball  14  (made from, for example, a plastic material or rubber) which is located in the bore  12 . The ball  14  is trapped in the bore  12  by a plate  15 . The plate  15  can be permanently attached to the housing  11  by a staking or a press fit operation. Or the plate  15  may be attached to the housing  11  by threading the plate  15  into the housing  11  to provide access and serviceability of the ball  4 . The plate  15  includes an opening  16  with a diameter X and also includes a set of slots  16 A that extend outward from the opening  16 . 
         [0021]    When a flooding condition occurs, water enters the bore  12  through the opening  16  in the plate  15 . The ball  14  floats and moves from a resting position ( 1 ) to a sealing position ( 2 ), where the ball  14  contacts the cone surface  13  in the bore  12 , thereby preventing water from entering the housing  11 . If flooding is happening for an extended period of time, some water may enter the area  21  of the clutch assembly ( FIG. 1 ). When the flooding condition ends, and the water level drops below the sealing position ( 2 ), the ball  14  floats on the water and lowers its position to position ( 1 ) as the water drains out of the hole  16  until the ball  14  contacts the plate  15  around the circumference of the hole  16 . Any water which already entered the clutch housing  11  flows out of the housing  11  and the bore  12  through the slots  16 A around the opening  16 . 
         [0022]    In general, to maintain proper functionality, the cone surface  13  and the ball  14  are not contaminated with dust, mud, etc. Usually the bottom of the housing  11  is exposed to contaminants during normal operating conditions as well as during flooding conditions. Accordingly, in another arrangement of a sealing and drainage device  131  ( FIGS. 3A and 3B ), an anti-contamination feature is included. Specifically, the sealing and drainage device  131  includes a plunger assembly  22  with a spring  19 . The plunger assembly  22  also includes an outer plug  17  and an inner plug  18 . Again, the ball  14  is placed inside the bore  12 . The bore  12  is closed with a plate assembly  15 A ( FIG. 4 ). In the implementation shown in  FIG. 3A  and  FIG. 4 , the plate assembly  15 A incorporates the plate  15 , the plunger assembly  22 , and the spring  19 . 
         [0023]    The plate assembly  15 A is assembled by inserting the inner plug  18  into the opening  16  of the plate  15  (see, for example,  FIG. 2B  and  FIG. 4 ), then the spring  19  is dropped onto the plate  15 , the outer plug  17  is slid onto the inner plug  18  until a set of locking features  18 a ( FIG. 5 ) engages with the outer plug  17 . In an alternative arrangement, a sealing and drainage device  231  includes a locking feature such as a pin  111  to lock the outer plug  17  and the inner plug  18  together, as shown in  FIG. 6 . 
         [0024]    The sealing and drainage device  131  shown in  FIG. 3A  contains the ball  14  trapped within the bore  12  and the plate assembly  15 A. The ball  14  is held inside the bore  12  by a spring  20  above the plunger assembly  22 . The plate assembly  15 A may be attached to the housing  11  by staking or press fitting the plate assembly  15 A into the housing  11 . Alternatively, the plate assembly  15 A may be threaded into the housing  11  to allow removal of the plate assembly  15 A so that the ball  14  and the plunger assembly  22  can be serviced. 
         [0025]    In the assembled condition, the spring  19  pushes the plunger assembly  22  up such that the outer flange surface  18 b of the inner plunger  18  contacts the plate  15 . As such, the opening  16  is closed off to protect the bore  12 , the ball  14 , and the plunger assembly  22  from contamination. Also note that the plunger assembly  22  in the up position slows the water flow into the bore  12  during flooding conditions. 
         [0026]    When a flooding condition occurs, water enters the bore  12  through the opening  16  in the plate  15 . The ball  14  floats and moves from the resting position to the sealing position, where the ball  14  contacts the cone surface  13  in the bore  12 , thereby preventing water from entering into the housing  11 . When the flooding condition ends and the water level drops below the sealing position, the ball  14  floats on the water and lowers its position as the water drains out of the hole  16 . Note that when the flooding condition is diminishing and the surrounding water level drops, the water pressure head acting on inner plug  18  of the plunger assembly  22  collapses the spring  19  and moves the plunger assembly  22  down to further facilitate drainage of the water out of the housing  11 . Any remaining water flows out of the housing  11  and the bore  12  through the slots  16 A around the opening  16 . 
         [0027]    During the operation of the vehicle, it moves up and down, because of road interactions and vehicle acceleration/deceleration. This vehicle movement translates to movement of the sealing and drainage device  131  as well, since vertical vehicle motions create inertia forces on the sealing and drainage device  131 . As such, the plunger assembly  22  inertia forces cause the spring  19  to deflect, which in turn allows the plugs  17  and  18  to move slightly up and down. This movement provides a self-cleaning mechanism for the plunger assembly  22  and the plate assembly  15 A, which further improves cleanliness of the sealing and drainage device  131 . 
         [0028]    In another implementation shown as a sealing and drainage device  431  in  FIG. 7 , the ball  14  and the plate assembly  15 A arrives to the assembly line in a self-contained capsule C. The sealing and drainage device  431  may be assembled in a number of ways. For example, the ball housing  112  with the coned surface  113  may be designed as a separate part and press fit into the housing  11 , and then the plate assembly  15 A can be threaded into the housing  11 . In another arrangement, the ball housing  112  is attached to the plate assembly  15 A and then as a one assembly attached to the housing  11 . 
         [0029]    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.