Abstract:
Provided is an electronic key in which a waterproof rubber can be prevented from getting damaged at the time of assembling various parts into an upper case. This electronic key includes: upper case ( 10 ) and lower case ( 20 ) that fit together and seal the interior thereof; inner case ( 30 ) covered by upper case ( 10 ) and lower case ( 20 ) and having, on the lower-surface side thereof, battery ( 39 ) that drives an electronic circuit performing communication with the exterior; waterproof rubber ( 40 ) covering the upper-surface side of inner case ( 30 ); upper-case projection ( 18 ) that projects from the inner wall of upper case ( 10 ); and waterproof-rubber outer-wall recess ( 45 ) that is recessed in the outer wall surface of waterproof rubber ( 40 ) and receives upper-case projection ( 18 ). A space is provided between upper-case projection ( 18 ) and waterproof-rubber outer-wall recess ( 45 ).

Description:
TECHNICAL FIELD 
     The present invention relates to an electronic key attached with a mechanical emergency key and used in a remote control system for opening and closing a door. 
     BACKGROUND ART 
     In recent years, a vehicle is equipped with a remote control system which performs wireless communication between an on-vehicle control unit and an electronic key held by a user so as to open and close doors of the vehicle in a non-contact manner. The electronic key which is carried outside the vehicle by the user is equipped with an inner casing in which an electronic circuit for performing wireless communication with the control unit is installed, and a battery for driving the electronic circuit. In order to prevent a failure of the electronic circuit inside the electronic key, a waterproof rubber is provided inside the casing of the electronic key for the waterproof and dustproof purposes. The waterproof rubber covers an upper surface side of the inner casing and is coupled to an upper casing. The battery is provided at the lower surface side of the inner casing (for example, see PTL 1). 
     CITATION LIST 
     Patent Literature 
     PTL 1 
     
         
         Japanese Patent Application Laid-Open No. 2010-189971 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     When a lower casing is separated from the upper casing for a user to replace the battery of the electronic key, it is favorable for the inner casing to be held by the upper casing so that inner parts such as the waterproof rubber and the inner casing are not separated from the upper casing. In a case where the waterproof rubber is held by the upper casing, a projection which is projected from an inner wall of the upper casing toward the waterproof rubber is fitted to the waterproof rubber. When the inner casing is held by the waterproof rubber, a projection which is projected from an outer wall of the inner casing toward the waterproof rubber is fitted to the waterproof rubber. Accordingly, the inner casing is strongly held by the upper casing. 
     However, an increase in an external force applied to the upper casing sometimes causes separation of parts such as the inner casing and the waterproof rubber from the upper casing. When such separation occurs, the user assembles various parts to the upper casing again. However, assembling the inner casing to the waterproof rubber after the waterproof rubber is assembled to the upper casing involves a problem causing breakage of the waterproof rubber. This problem will be described below. 
     First, the waterproof rubber is pressed by the projection of the inner casing at the position of the projection of the upper casing when the inner casing is assembled to the waterproof rubber. At this time, the pressed waterproof rubber attempts to move toward the projection of the upper casing. However, the waterproof rubber at the position of the projection of the upper casing is nipped between the projection of the upper casing and the projection of the inner casing, and is compressed more than a compression limit. As a result, there occurs a problem causing breakage of the waterproof rubber. 
     Furthermore, an increase in an external force applied to the upper casing sometimes causes separation of parts such as the inner casing and the waterproof rubber from the upper casing. When such separation occurs, the user assembles various parts to the upper casing again. However, assembling the inner casing to the upper casing after the waterproof rubber is assembled to the inner casing involves a problem causing breakage of the waterproof rubber. This problem will be described below 
     First, the waterproof rubber is pressed by the projection of the upper casing at the position of the projection of the inner casing when the inner casing is assembled to the upper casing. At this time, the pressed waterproof rubber attempts to move toward the projection of the inner casing. However, the waterproof rubber at the position of the projection of the inner casing is nipped between the projection of the upper casing and the projection of the inner casing, and is compressed more than the compression limit. As a result, there occurs a problem causing breakage of the waterproof rubber. 
     It is an object of the present invention to solve the above-described problems and to provide an electronic key capable of preventing breakage of a waterproof rubber during assembly of various parts to an upper casing. 
     Solution to Problem 
     An electronic key according to an aspect of the present invention includes: upper and lower casings that are fitted to each other so as to seal the inside of the casings; an inner casing that is covered by the upper and lower casings and that has a battery mounted on a lower surface side of the inner casing, the battery being used to drive an electronic circuit configured to communicate with the outside of the electronic key; a waterproof rubber that covers an upper surface side of the inner casing; an upper casing projection that projects from an inner wall surface of the upper casing; and a waterproof-rubber outer-wall recess portion that is recessed from an outer wall surface of the waterproof rubber and that houses the upper casing projection, in which a gap is formed between the upper casing projection and the waterproof-rubber outer-wall recess portion. 
     Furthermore, an electronic key according to an aspect of the present invention includes: upper and lower casings that are fitted to each other so as to seal the inside of the casings; an inner casing that is covered by the upper and lower casings and that has a battery mounted on a lower surface side of the inner casing, the battery being used to drive an electronic circuit configured to communicate with the outside of the electronic key; a waterproof rubber that covers an upper surface side of the inner casing; an inner casing projection that projects from an outer wall surface of the inner casing; and a waterproof-rubber inner-wall recess portion that is recessed from an inner wall surface of the waterproof rubber and that houses the inner casing projection, in which a gap is formed between the inner casing projection and the waterproof-rubber inner-wall recess portion. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to prevent breakage of a waterproof rubber during assembly of various parts to an upper casing. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating an electronic key of an embodiment; 
         FIG. 2  is an exploded perspective view of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view when the exploded perspective view of  FIG. 2  is viewed upside down; 
         FIG. 4  is a cross-sectional view when the cross-section A-A of  FIG. 1  is viewed in direction B; and 
         FIG. 5  is an enlarged view of region C of  FIG. 4 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an electronic key according to an embodiment of the present invention will be described with reference to the drawings. 
       FIG. 1  is a perspective view illustrating an electronic key of the embodiment.  FIG. 2  is an exploded perspective view of  FIG. 1 .  FIG. 3  is an exploded perspective view when the exploded perspective view of  FIG. 2  is viewed upside down.  FIG. 4  is a cross-section when cross-section A-A of  FIG. 1  is viewed from direction B.  FIG. 5  is an enlarged view of region C of  FIG. 4 . 
     As illustrated in  FIGS. 1 to 3 , the electronic key includes upper casing  10 , lower casing  20 , inner casing  30  which is covered by upper casing  10  and lower casing  20 , waterproof rubber  40  which covers the upper surface side of inner casing  30 , and emergency key  100  which is accommodated to lower casing  20  for the emergency purpose. 
     Upper casing  10 , lower casing  20  and inner casing  30  are made of resin. Upper casing  10  is coupled to lower casing  20  so as to house inner casing  30  and waterproof rubber  40  therein. Upper casing  10  is provided with button  11  including three buttons  11   a  to  11   c.    
     The side wall of lower casing  20  is provided with locking claws  21 . Locking claws  21  are respectively fitted to fitting portions  14  provided in the inner wall of upper casing  10 . As illustrated in  FIG. 4 , lower casing  20  is provided with insertion portion  22  into which bar-like portion  101  of emergency key  100  is inserted. Furthermore, lower casing  20  is provided with recess portion  23  which is recessed from the upper surface of insertion portion  22 . The bottom surface of lower casing  20  is provided with knob  24  which locks bar-like portion  101  of emergency key  100 . When knob  24  is moved in a direction toward insertion portion  22 , emergency key  100  is held by lower casing  20 . Meanwhile, emergency key  100  is detachable from lower casing  20  by moving knob  24  in a direction away from insertion portion  22 . 
     Circuit board  36  is disposed inside inner casing  30 . The upper surface of circuit board  36  is provided with switches  31   a  to  31   c . Further, inner casing projections  32  are projected from the upper portion of the outer wall surface of inner casing  30 . Inner casing projections  32  are projected from each of both longitudinal end portions of the outer walls of inner casing  30 . 
     Cover portion  33  is placed on the upper portion of inner casing  30 . Cover portion  33  covers the upper surface of circuit board  36 . The cover portion  33  includes three openings. Switches  31   a  to  31   c  are exposed through the openings. In cover portion  33 , protruding portions  33   a  and  33   b  are respectively provided at the left and right sides of switch  31   b.    
     The lower surface of inner casing  30  is provided with electronic circuit  37  which communicates with the outside, and battery  39  which drives electronic circuit  37 . The lower surface of inner casing  30  is provided with holder  38 . Battery  39  is held in inner casing  30  by holder  38 . Holder  38  is placed on positioning recess portion  25  which is formed in a bottom surface of recess portion  23  of lower casing  20 . 
     Waterproof rubber  40  is made of an elastic material and seals the upper surface of inner casing  30 . The elastic material is made of, for example, rubber. Waterproof rubber  40  includes pressing portions  41   a  to  41   c  which protrude toward the upper surface side. When buttons  11   a  to  11   c  are pressed, pressing portions  41   a  to  41   c  provided in waterproof rubber  40  and switches  31   a  to  31   c  disposed in inner casing  30  are respectively pressed. In addition, waterproof rubber  40  further includes protection portions  41   d  and  41   e  which are respectively provided at the left and right sides of pressing portion  41   b.  Protection portions  41   d  and  41   e  are respectively disposed on the protruding portions  33   a  and  33   b  of cover portion  33 . Waterproof rubber projection  42  is projected from the upper portion of the outer wall surface of waterproof rubber  40 . Waterproof rubber projections  42  are projected from each of both longitudinal end portions of the outer wall surfaces of waterproof rubber  40 . Waterproof rubber projections  42  are respectively fitted to upper casing recess portions  13  formed in the bottom surface inside upper casing  10 . In the inner wall surface of waterproof rubber  40 , the inner wall surfaces of waterproof rubber projections  42  are provided respectively with waterproof-rubber inner-wall recess portions  43  which are recessed from the inner wall surfaces of waterproof rubber  40 . Inner casing projections  32  are housed in the waterproof-rubber inner-wall recess portions  43 , respectively. 
     Next, a description will be given regarding a state where the respective components of the electronic key are assembled. As illustrated in  FIGS. 4  and  5 , each fitting portion  14  of upper casing  10  is fitted to locking claw  21  of lower casing  20 . The front end of waterproof rubber  40  is pressed against the upper end of locking claw  21 . Accordingly, a space between lower casing  20  and waterproof rubber  40  is sealed. 
     Button  11   c  includes flange portions  15  each extending in a flange shape from the bottom surface thereof. The upper surface of flange portion  15  is in contact with the lower surface of opening end  16  of upper casing  10 . Upper casing  10  includes fixing portions  17  each projecting from the lower surface of opening end  16  and configured to fix waterproof rubber  40 . Fixing portions  17  and cover portions  33  are in contact with waterproof rubber  40  while interposing waterproof rubber  40  in between. Ends  34  of cover portions  33  extend respectively from cover portions  33  in the up and down direction. The side wall of each of ends  34  is in contact with the inner wall surface of inner casing  30 . 
     Waterproof rubber projections  42  of waterproof rubber  40  are each formed in a shape which is swollen upward with respect to the flat portion of waterproof rubber  40 . Waterproof rubber projections  42  are fitted respectively to upper casing recess portions  13  of upper casing  10 . A gap is partially formed between each of waterproof rubber projections  42  and a corresponding one of upper casing recess portions  13 . The lower end of upper casing recess portion  13  is in contact with waterproof rubber projection  42 . 
     Because of the swollen portion of waterproof rubber projection  42 , the inner wall surface of waterproof rubber projection  42  is provided with waterproof-rubber inner-wall recess portion  43  which is recessed with respect to the flat portion of waterproof rubber  40 . Inner casing projection  32  is fitted to waterproof-rubber inner-wall recess portion  43 . The upper end of end  34  of cover portion  33  is also fitted to waterproof-rubber inner-wall recess portion  43 . 
     Each inner casing projection  32  further includes claw portion  35 . Claw portion  35  extends outward in a flange shape from inner casing projection  32 . In addition, waterproof-rubber inner-wall recess portion  43  of waterproof rubber  40  includes locking recess portion  44  which is further recessed outward. Claw portion  35  is locked to locking recess portion  44 . The lower surface of claw portion  35  is in contact with the upper surface of locking recess portion  44 . Accordingly, inner casing  30  is held by waterproof rubber  40 . Further, the outer wall surfaces of inner casing  30  positioned at the lower side of inner casing projections  32  are also in contact with the inner wall surfaces of waterproof rubber projections  42  of waterproof rubber  40 . 
     Inner wall surfaces of upper casing  10  are each provided with upper casing projection  18 . The boundary of upper casing recess portion  13  is defined by upper casing projection  18 . The front end of each waterproof rubber projection  42  of waterproof rubber  40  is provided with waterproof-rubber outer-wall recess portion  45  which is recessed from the outer wall surface of waterproof rubber  40 . Upper casing projection  18  is housed in waterproof-rubber outer-wall recess portion  45 . The upper surface of upper casing projection  18  and the lower surface of waterproof-rubber outer-wall recess portion  45  are formed so as to be in contact with each other. Accordingly, waterproof rubber  40  is held by upper casing  10 . 
     Each upper casing projection  18  is formed at a lower position than inner casing projection  32 . In other words, inner casing projection  32  is formed at an upper position than upper casing projection  18 . With this configuration, inner casing  30  can be held by upper casing  10  through waterproof rubber  40 . That is, claw portion  35  is locked to locking recess portion  44  in waterproof-rubber inner-wall recess portion  43 , so that inner casing  30  is held by waterproof rubber  40 . When inner casing projection  32  is positioned at an upper position than upper casing projection  18 , waterproof rubber  40  is held by upper casing  10  along with inner casing  30  by locking waterproof-rubber outer-wall recess portion  45  to upper casing projection  18 . 
     A gap is formed between each proof rubber outer-wall recess portion  45  and corresponding upper casing projection  18 . Accordingly, it is possible to prevent breakage of waterproof rubber  40  during assembling of inner casing  30  to upper casing  10  assembled with waterproof rubber  40 . 
     Hereinafter, why breakage can be prevented will be described. During assembly of inner casing  30  to upper casing  10  assembled with waterproof rubber  40 , waterproof rubber  40  is compressed the most when upper casing projections  18  face inner casing projections  32  with claw portions  35 . At this time, the lateral distance between inner casing projection  32  and upper casing projection  18  is expressed by the distance between the front end of claw portion  35  and the front end of upper casing projection  18 . Since a gap is formed between upper casing projection  18  and waterproof-rubber outer-wall recess portion  45 , waterproof rubber  40  which is pressed by claw portion  35  of inner casing projection  32  can escape to the gap between upper casing projection  18  and waterproof-rubber outer-wall recess portion  45 . Accordingly, it is possible to prevent breakage of the portion of waterproof-rubber outer-wall recess portion  45  of waterproof rubber  40  when the portion thereof is compressed more than the compression limit. 
     Further, at least a gap is partially formed between each waterproof-rubber inner-wall recess portion  43  and corresponding inner casing projection  32 . In other words, a gap is formed between claw portion  35  and locking recess portion  44 . Accordingly, it is possible to prevent breakage of waterproof rubber  40  during assembly of inner casing  30  assembled with waterproof rubber  40  to upper casing  10 . 
     Hereinafter, why breakage can be prevented will be described. During assembly of inner casing  30  assembled with waterproof rubber  40  to upper casing  10 , waterproof rubber  40  is compressed the most when upper casing projections  18  face inner casing projections  32  with claw portions  35 . At this time, the lateral distance between the inner casing projection  32  and the upper casing projection  18  is expressed by the distance between the front end of claw portion  35  and the front end of upper casing projection  18 . Since a gap is formed between claw portion  35  and locking recess portion  44 , waterproof rubber  40  which is pressed by upper casing projection  18  can escape to the gap between claw portion  35  and locking recess portion  44 . Accordingly, it is possible to prevent breakage of the portion of locking recess portion  44  of waterproof rubber  40  when the portion is compressed more than the compression limit. 
     As described above, according to the electronic key of the embodiment, since a gap is formed between each upper casing projection  18  and corresponding waterproof-rubber outer-wall recess portion  45 , waterproof-rubber outer-wall recess portion  45  can escape to the gap between upper casing projection  18  and waterproof-rubber outer-wall recess portion  45  even when the waterproof-rubber outer-wall recess portion is pressed by claw portion  35  of inner casing projection  32 . Accordingly, it is possible to suppress an increase in compression rate of the portion of waterproof-rubber outer-wall recess portion  45  in waterproof rubber  40  so that the compression rate is not greater than the compression limit. Accordingly, it is possible to prevent breakage of waterproof rubber  40  even when inner casing  30  is assembled to upper casing  10  assembled with waterproof rubber  40 . 
     Further, according to the electronic key of the embodiment, since a gap is formed between each inner casing projection  32  and corresponding waterproof-rubber inner-wall recess portion  43 , waterproof-rubber inner-wall recess portion  43  can escape to the gap between inner casing projection  32  and waterproof-rubber inner-wall recess portion  43  even when waterproof-rubber inner-wall portion is pressed by upper casing projection  18 . Accordingly, it is possible to suppress an increase in compression rate of the portion of waterproof-rubber inner-wall recess portion  43  in waterproof rubber  40  so that the compression rate is not greater than the compression limit. Accordingly, it is possible to prevent breakage of waterproof rubber  40  even during assembly of inner casing  30  assembled with waterproof rubber  40  to upper casing  10 . 
     Further, the inner wall surface of upper casing  10  and the outer wall surface of waterproof rubber  40  are in contact with each other at the upper position than upper casing projection  18 , while the outer wall surface of inner casing  30  and the inner wall surface of waterproof rubber  40  are in contact with each other at the lower position than inner casing projection  32 . Accordingly, it is possible to prevent breakage of waterproof rubber  40  and maintain a holding force of upper casing  10 , inner casing  30 , and waterproof rubber  40 . 
     The disclosures of the specifications, drawings and abstracts of Japanese Patent Application Nos. 2011-75031 and 2011-75032 filed on Mar. 30, 2011, are incorporated herein by reference in their entirety. 
     INDUSTRIAL APPLICABILITY 
     The electronic key according to the present invention is useful for a remote control system which communicates with the outside. Particularly, the electronic key is useful for a keyless entry system involving replacement of a battery. 
     REFERENCE SIGNS LIST 
     
         
           10  Upper casing 
           18  Upper casing projection 
           20  Lower casing 
           30  Inner casing 
           32  Inner casing projection 
           39  Battery 
           43  Waterproof-rubber inner-wall recess portion 
           45  Waterproof-rubber outer-wall recess portion