Patent Abstract:
A switch box for a vehicle door lock device comprises a slide pin which has one end abutting against a side surface of a latch that engages with and is fixed to the striker and slides in response to a pivot motion of the latch, a slider which is connected and fixed to the other end of the slide pin and on which an elastic slide contact is disposed, a pair of terminals which are short-circuited to be connected to each other by the slide contact depending on a slide position of the slider, and a switch box cover substantially covering them in the lock body case, and the switch box cover has a through hole for ventilation at that position thereof which corresponds to a lower side of one side surface thereof when the switch box cover is attached to the vehicle door.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-138727, filed May 9, 2001, the entire contents of which are incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a switch box for a vehicle door apparatus having a powered door lock function.  
           [0004]    2. Description of the Related Art  
           [0005]    [0005]FIGS. 1 and 2 show the arrangement of part of a vehicle door lock device having a powered door lock function (see Jpn. Pat. Appln. KOKAI Publication No. 8-326387). Referring to FIGS. 1 and 2, a recess  2  is formed in the lower portion of the front surface of a synthetic-resin body  1  of the door lock device. A latch  3  and ratchet  4  are pivotally supported in the recess  2  by shafts  5  and  6 , respectively.  
           [0006]    The latch  3  is biased counterclockwise in FIG. 1 by a spring (not shown). Upon a door closing operation, when the latch  3  engages with a striker  7  fixed to the car body, it rotates counterclockwise. Hence, the latch  3  rotates to its full-latch state through a state (a so-called half-latch state) where it engages with its half-latch stepped portion  8 .  
           [0007]    A switch  34  is provided to abut against the side surface of the latch  3 . The switch  34  detects the full-latch state of the latch  3  which engages with the striker  7  fixed to the car body side when the door is closed.  
           [0008]    The switch  34  has an electrical switch mechanism which is ON when the latch is in the full-latch state. As shown in FIG. 1, most of the switch  34 , excluding one end of its pin abutting against the side surface of the latch  3 , is housed in an actuator housing chamber  20  which houses a powered actuator unit  17  (to be described later).  
           [0009]    The actuator housing chamber  20  is surrounded by a base case  18  and a cover case (not shown). The base case  18  is integrally formed with the upper portion of the body  1 . The cover case is fixed to the base case  18 .  
           [0010]    A lock lever (not shown) is axially supported by the latch shaft  5  and is switched between a lock position and unlock position. The actuator unit  17  in the actuator housing chamber  20  switches this lock lever between the lock position and unlock position.  
           [0011]    [0011]FIG. 2 is a view schematically showing the actuator unit  17  housed in the actuator housing chamber  20  together with the switch  34 . A gear  22  is fixed to the rotating shaft of a motor  21 . A gear disk  23  meshes with the gear  22 .  
           [0012]    The gear disk  23  has a small-diameter gear  24  coaxial with it. A sector gear  25  rotatably axially supported by a shaft  26  meshes with the small-diameter gear  24 .  
           [0013]    The sector gear  25  is held at a neutral position at the center by a spring (not shown). When the motor  21  rotates in the forward or reverse direction, the sector gear  25  rotates clockwise or counterclockwise.  
           [0014]    A projection  28  is formed on the distal end of a change lever  27  fixed to the shaft  26 . The projection  28  engages with a wide recess  29  of the sector gear  25  with a lost motion linkage.  
           [0015]    One end of the shaft  26  projects outward through the shaft hole of the cover case, and an output gear is fixed to this projecting portion. The output gear meshes with a gear portion formed on the lock lever.  
           [0016]    The gear  22  fixed to the rotating shaft of the motor  21  rotates in the forward or reverse direction to rotate the gear disk  23 . Then, the small-diameter gear  24  integrally formed with the gear disk  23  rotates the sector gear  25  within a predetermined range from the neutral position at the center.  
           [0017]    Thus, the projection  28  of the change lever  27  engaging with the large-width recess  29  with the lost motion linkage engages with the sector gear  25  over the lost motion linkage and is rotated by it. Then, an output gear  31  fixed to the other end of the shaft  26  of the change lever  27  is rotated to pivot a lock gear  14  through its gear portion  32 .  
           [0018]    Therefore, the forward/reverse rotation of the motor  21  is transmitted to the lock lever (not shown) through a mechanism in the actuator unit  17 . Thus, the lock lever is switched from the lock position to the unlock position or vice versa. After this, power supply to the motor  21  is ended and the rotational torque of the motor  21  disappears. Then, the sector gear  25  is automatically restored to the neutral position at the center by the elasticity of the spring.  
           [0019]    As described above, the switch  34  is housed in the actuator housing chamber  20  together with the actuator unit  17 . The distal end of the projecting pin of the switch  34  abuts against the side surface of the latch  3 .  
           [0020]    In the switch  34 , one end of the pin biased by the spring projects to abut against the side surface of the latch  3 , as described above. The other end of the pin is connected to an electrical contact piece which is ON when the latch  3  is in the full-latch state.  
           [0021]    Since a vehicle door lock device is attached and fixed to the inner side of the steel plate of a vehicle door, it is adversely affected by the atmospheric temperature more easily than various types of components provided in the vehicle compartment.  
           [0022]    The switch  34  is housed in the actuator housing chamber  20  together with other actuator unit  17  and the like. However, since the switch  34  particularly has an electric contact or the like, it may result in an operation failure due to dew condensation or the like.  
         BRIEF SUMMARY OF THE INVENTION  
         [0023]    It is an object of the present invention to provide a switch box for a vehicle door lock device, in which the adverse influence of dew condensation and the like caused by a temperature change is eliminated as much as possible so the operating state of a latch can be reliably detected under any condition.  
           [0024]    A switch box for a vehicle door lock device for a vehicle door lock device, which is integrally housed in a lock body case and engages with and is fixed to a striker of a vehicle door, according to one aspect of the present invention is characterized by comprising: a slide pin which has one end abutting against a side surface of a latch that engages with and is fixed to the striker of a vehicle, and which slides in response to a pivot motion of the latch when biased by a spring; a slider which is connected and fixed to the other end of the slide pin and on which an elastic slide contact is disposed; a pair of terminals which are short-circuited to be connected to each other by the slide contact depending on a slide position of the slider; and a switch box cover which substantially hermetically covers most of the slide pin, excluding one end thereof abutting against the side surface of the latch, the spring, the slider, and the terminals in the lock body case, and the switch box cover has a through hole for ventilation at that position thereof which corresponds to a lower side of one side surface thereof when the switch box cover is attached to the vehicle door. The adverse influence of dew condensation and the like caused by a temperature change is eliminated as much as possible, so the operating state of the latch can be reliably detected under any condition.  
           [0025]    Preferred manners of the switch box for a vehicle door lock device described above are as follows. The following manners may be used alone each, or may be appropriately combined.  
           [0026]    (1) A path extending from the through hole for ventilation to an interior of the switch box is bent. The possibility that water may enter the switch box directly by any chance can be minimized.  
           [0027]    (2) The switch box cover further has a through hole for drainage at that position thereof which corresponds to a lowermost end of one side surface of the switch box cover when the switch box cover is attached to the vehicle door. Water in the switch box can be drained immediately.  
           [0028]    Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0029]    The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.  
         [0030]    [0030]FIG. 1 is a cross-sectional plan view showing the arrangement of mainly a latch, ratchet, and car body striker in a conventional door lock device;  
         [0031]    [0031]FIG. 2 is a cross-sectional plan view showing the arrangement of mainly an actuator unit in the conventional door lock device;  
         [0032]    [0032]FIG. 3 is a perspective view showing the arrangement of a synthetic-resin body in a vehicle door lock device according to an embodiment of the present invention;  
         [0033]    [0033]FIG. 4 is a perspective view showing the arrangement of a switch cover, slide pin, and slider;  
         [0034]    [0034]FIG. 5 is a view for explaining a path extending from a vent hole to the interior of a switch box (a portion covered by the switch cover);  
         [0035]    [0035]FIG. 6 is a perspective view showing the respective members that form the switch box;  
         [0036]    [0036]FIG. 7 is a perspective view showing how the slider and slide pin are attached to the lower portion of the switch box; and  
         [0037]    [0037]FIG. 8 is a perspective view showing how the switch cover is attached to the lower portion of the switch box. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0038]    A vehicle door lock device according to an embodiment of the present invention will be described with reference to the accompanying drawings.  
         [0039]    [0039]FIG. 3 is a view showing the arrangement of a synthetic-resin body  51  in the vehicle door lock device. As shown in FIG. 3, a switch box lower portion  52  is formed on the inner surface of the synthetic resin body  51  to be integral with it. A notch  53  is formed in part of the side wall of the switch box lower portion  52 . The notch  53  forms a vent maze (to be described later).  
         [0040]    [0040]FIG. 4 is a view showing the arrangement of a switch cover  54 , slide pin  55 , slider  56 , and the like. The switch cover  54  is fitted in the switch box lower portion  52  to form a switch box. The slide pin  55  and slider  56  are sealed in the switch box.  
         [0041]    Referring to FIG. 4, one distal end of the slide pin  55  provided in the body  51  forms a hemispherical shape and abuts against the side surface of a latch (not shown). A coiled spring  57  is mounted on the slide pin  55 . The other distal end of the slide pin  55  forms a stepped portion. This stepped portion is fitted in a stepped groove  56 a of the slider  56 . Hence, the slide pin  55  and slider  56  integrally slide in the switch box.  
         [0042]    The slider  56  is formed of an insulating member. A slide contact  58  is attached and fixed to one side surface of the slider  56 . The slide contact  58  has a pair of open legs formed by bending an elastic metal plate.  
         [0043]    The switch cover  54  has a thin structure. Thus, part of the side wall of the switch cover  54  which abuts against the notch  53  forms a recess  59  with respect to the surrounding wall surface. The recess  59  has a vent hole  60  at its one end. The vent hole  60  extends to that upper surface of the cover which corresponds to the lower side in FIG. 4.  
         [0044]    Assume that the switch box is formed by covering the switch box lower portion  52  with the switch cover  54  such that the inner surface of the side wall of the switch cover  54  abuts against the outer surface of the side wall of the switch box lower portion  52 . In this case, the bent vent maze formed of the vent hole  60 , recess  59 , and notch  53  realizes ventilation between the interior and the outer side of the switch box.  
         [0045]    In addition, similarly to the vent hole  60 , a drain hole  64  is formed at that position in the switch cover  54  which is in the vicinity of the lowermost end of the switch box when the door lock device is attached to the vehicle door. The drain  64  extends to the upper surface of the cover.  
         [0046]    A path extending from the vent hole  60  to the interior of the switch box (portion covered by the switch cover) will be described with reference to FIG. 5. The vent hole  60  extending to the upper surface of the switch cover  54  is formed at the end of the recess  59 . Thus, the recess  59  is ventilated by the vent hole  60  extending to the upper surface of the switch cover  54 . The interior of the switch box communicates with the recess  59  through the notch  53 . In this manner, ventilation is ensured in the switch box. The path extending from the vent hole  60  to the interior of the switch box is bent twice, as is apparent from FIG. 5. Therefore, direct entering of water from the vent hole  60  into the switch box can be avoided as much as possible. That portion of the switch cover  54  which is provided with the slide pin  55  communicates with the recess  59  through the notch  53 . That portion of the switch cover  54  which is provided with the slide pin  55  has the drain hole  64 . Thus, water in the switch box can be discharged immediately.  
         [0047]    A protrusion  61  is formed on the inner side of the upper surface of the switch cover  54 . The protrusion  61  fits in a groove formed in the lower surface of the slider  56  to define the slide direction of the slider  56 . A stopper  62  formed of a protrusion and a pair of terminal retaining protrusions  63  are also formed on the inner side of the upper surface of the switch cover  54 . The stopper  62  regulates the slide range of the slider  56 . The pair of terminal retaining protrusions  63  are parallel to each other to sandwich the protrusion  61 , and press terminals (to be described later) against the inner bottom surface of the switch box lower portion  52 .  
         [0048]    [0048]FIG. 6 is an exploded perspective view showing the respective members that are attached to the switch box lower portion  52  to form the switch box.  
         [0049]    Terminal grooves are formed in the inner surface of the switch box lower portion  52  shown in FIG. 3. A pair of terminals  65 A and  65 B formed by bending are fitted in the terminal grooves from below in FIG. 6. The slider  56  and the slide pin  55  are integrally placed above the pair of terminals  65 A and  65 B, as shown in FIG. 7. The slider  56  has the slide contact  58 . The spring  57  is mounted on the slide pin  55 .  
         [0050]    The switch cover  54  is attached and fixed to the switch box lower portion  52  through a waterproof packing  66  by threadable engagement of, e.g., three set screws  67 . Hence, the switch box as shown in FIG. 8 is completed.  
         [0051]    One projecting end of the slide pin  55  in the switch box abuts against the side surface of the latch  3  (not shown) upon a biasing operation of the spring  57 , as shown in FIG. 7. Thus, the slide pin  55  slides the slider  56  to a position corresponding to the pivoting state of the latch  3 . At a slide position where the latch  3  becomes full-latched, the slide contact  58  attached to the slider  56  short-circuits the pair of terminals  65 A and  65 B.  
         [0052]    Therefore, whether or not the latch  3  is in the full-latch state can be known by, e.g., detecting electrical connection between the terminals  65 A and  65 B from the outside.  
         [0053]    In the above arrangement, the switch cover  54  is attached to the switch box lower portion  52  by using the waterproof packing  66  as well. Thus, hermeticity in the switch box is maintained. Also, water and the like can be prevented from entering the switch box from the attaching surface of the switch cover  54 .  
         [0054]    With an ordinary hermetic structure, when a sharp temperature change or the like occurs, dew condensation may occur in it. According to the present invention, even in such a case, ventilation between the interior and the outer side of the switch box is maintained through the vent hole  60 , as shown in FIG. 8. Thus, no large temperature difference occurs. This minimizes the possibility of dew condensation in the switch box. Consequently, the operating state of the latch can be detected reliably.  
         [0055]    Particularly, the vent path is formed in a bent manner of the vent hole  60  and recess  59  of the switch cover  54 , and the notch  53  of the switch box lower portion  52 . This minimizes the possibility of direct water entering into the switch box.  
         [0056]    The drain hole  64  is formed at that position of the switch cover  54  which corresponds to the lowermost end when the door lock device according to this embodiment is attached to the vehicle door, as shown in FIG. 8. Hence, even if water should enter the switch box, it can be discharged quickly.  
         [0057]    The shapes and the like of the respective components of the present invention are not limited to this embodiment, but can obviously be appropriately modified in accordance with their mutual connection, engaging relationship, and the like.  
         [0058]    The present invention is not limited to the embodiment described above, but can be modified and practiced in various manners within a range not departing from the spirit and scope of the invention.  
         [0059]    The above embodiments include inventions of various stages, and various types of inventions can be extracted through appropriate combinations of a plurality of disclosed constituent elements. For example, assume that even when several constituent elements are eliminated from all constituent elements shown in the embodiment, at least one of problems described referring to the problems to be solved by the invention can be solved, and at least one of the effects described referring to the effect of the invention can be obtained. In this case, an arrangement from which these several constituent elements are eliminated can be extracted as an invention.  
         [0060]    Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Technology Classification (CPC): 8