Abstract:
A remote control key that may easily be disassembled while preventing theft of its transponder. The remote control key includes a transmitter for transmitting a signal to remotely control locking and unlocking of a door. The transponder transmits a predetermined ID code. A housing retains the transmitter and the transponder. A pad is formed on the housing to operate the transmitter. A seal seals the transponder that is retained in the housing. The seal and the pad are formed from the same material.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to a remote control key for remotely controlling locking and unlocking of a door, and more particularly, to a remote control key that prevents theft of a transponder incorporated in the remote control key.  
           [0002]    Japanese Laid-Open Patent Publication No. 2002-213124 describes a prior art example of a vehicle lock that facilitates the locking and unlocking of a vehicle door. The vehicle lock is provided with a remote control key (door key), which includes a transmitter and a transponder. When a lock/unlock button (operation button) of the remote control key is operated, the transmitter transmits a stored ID code. The transponder receives a transponder drive signal from the vehicle and transmits a transponder signal for starting the engine. When receiving the ID code from the remote control key, the vehicle compares the ID code with a stored ID code. If the two ID codes match, the vehicle locks or unlocks the doors. Further, when an ID code included in the transponder signal transmitted from the transponder matches the ID code of the vehicle, the vehicle starts the engine.  
           [0003]    Japanese Laid-Open Patent Publication No. 9-105255 describes an example of such a remote control key (ignition key) that separately incorporates a transmitter and a transponder. The remote control key uses electromagnetic energy, which is supplied from the vehicle, to transmit an ID code. Another proposed type of remote control key incorporates a battery to drive a transmitter. The battery generates power and reduces power consumption in the vehicle.  
           [0004]    A further proposed type of a remote control key incorporates a transmitter and a transponder, which are formed integrally with each other to reduce the manufacturing steps and manufacturing cost of the remote control key.  
           [0005]    It is preferable that the remote control key be easily disassembled to facilitate maintenance, such as replacement of a battery or a transponder. However, when the disassembly of a remote control key is easy, a third person may disassemble the remote control key and remove the transponder. In addition, even if the transponder is removed, the removal of the transponder is not readily noticeable since it is light. Thus, when the remote control key may easily be disassembled, this may lower the security level of the vehicle.  
           [0006]    To prevent removal of the transponder, an adhesive agent or the like may be used to make disassembly of the remote control key difficult. However, this would cause difficulties in maintenance for the transmitter of the remote control key.  
         SUMMARY OF THE INVENTION  
         [0007]    It is an object of the present invention to provide a remote control key that enables easy disassembly while preventing theft of the transponder.  
           [0008]    To achieve the above object, the present invention provides a remote control key including a transmitter for transmitting a signal to remotely control locking and unlocking of a door. A transponder transmits a predetermined ID code. A housing retains the transmitter and the transponder. A pad is formed on an outer surface of the housing to operate the transmitter. A seal seals the transponder that is retained in the housing. The seal and the pad are formed from the same material.  
           [0009]    A further aspect of the present invention is a method for manufacturing a remote control key including a transmitter which transmits a signal to remotely control locking and unlocking of a door, and a transponder. The method includes retaining the transponder in a housing, forming a pad on the housing to operate the transmitter, and sealing the transponder with a material that forms the pad.  
           [0010]    Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:  
         [0012]    [0012]FIG. 1 is an exploded perspective view showing a remote control key according to a preferred embodiment of the present invention;  
         [0013]    [0013]FIG. 2 is a front view showing the remote control key of FIG. 1;  
         [0014]    FIGS.  3 ( a ) to  3 ( c ) are cross-sectional views taken along line  3 - 3  in FIG. 2 showing procedures for forming an operation pad and a seal in a housing, and FIG. 3( d ) is a rear view showing the remote control key before a cover is connected to the housing;  
         [0015]    FIGS.  4 ( a ) and  4 ( b ) are cross-sectional views taken along line  3 - 3  in FIG. 2 showing the remote control key when theft of the transponder leaves a mark on the outer surface of the remote control key when the transponder is stolen, and FIG. 4( c ) is a front view showing the remote control key when theft of the transponder leaves a mark on the outer surface of the remote control key;  
         [0016]    FIGS.  5 ( a ) and  5 ( d ) are front views showing a remote control key according to a further embodiment of the present invention, and FIGS.  5 ( b ) and  5 ( c ) are cross-sectional views taken along line  5 - 5  in FIG. 5( a ); and  
         [0017]    [0017]FIG. 6 is a side view showing a remote control key according to a further embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]    A remote control key  1  according to a preferred embodiment of the present invention will now be described with reference to FIGS.  1  to  4 ( c ). The remote control key  1  is used in a vehicle keyless entry system.  
         [0019]    As shown in FIGS. 1 and 2, the remote control key  1  includes a key plate  10 , a rectangular housing  11 , a transmitter  12 , a transponder  13 , and a cover  14 .  
         [0020]    The housing  11  is made of a hard resin, such as polycarbonate-polyethylene terephthalate (PC-PET), polybutylene terephthalate (PBT), acrylonitrile-butadiene-styrene (ABS) resin, and polycarbonate acrylonitrile-butadiene-styrene (PC-ABS). A basal portion of the key plate  10  is insert-molded in the lower portion of the housing  11 , as viewed in FIG. 1. A threaded hole  15  is formed in the housing  11  near the position where the key plate  10  is molded in the housing  11 . A stepped portion  16  extends along the periphery of the housing  11  on the surface facing towards the cover  14 .  
         [0021]    The housing  11  has two cavities, that is, a transmitter retainer  17  and transponder retainer  18 , which is smaller than the transmitter retainer  17 . The housing  11  includes a partition  19 , which separates the two cavities from one another. The partition  19  is formed in a corner of the housing  11  between a first inner wall of the housing  11  and a second inner wall, which is adjacent to the first inner wall. The partition  19  includes a first wall extending inward from the first inner wall and a second wall extending from the end of the first wall vertically downward to the second inner wall of the housing  11 , as viewed in FIG. 1. The transmitter retainer  17  and the transponder retainer  18  respectively retain the transmitter  12  and the transponder  13 . The dimensions of the transponder retainer  18  are slightly greater than that of the transponder  13 . This creates a gap between the transponder retainer  18  and the transponder  13 .  
         [0022]    The housing  11  has a bottom wall  20 . A lock button receptacle  21  extends through an upper portion of the bottom wall  20  (the portion separated from the key plate  10  as viewed in FIG. 1) in the transmitter retainer  17 . An unlock button receptacle  22  extends through the bottom wall  20  under the lock button receptacle  21  (the portion close to the key plate  10 ) in the transmitter retainer  17  and part of the transponder retainer  18 . Thus, the transponder retainer  18  is connected with the unlock button receptacle  22 , as shown in FIG. 3( a ). The lock button receptacle  21  and the unlock button receptacle  22  have the same shapes.  
         [0023]    Referring to FIGS.  2  to  4 ( c ), a flexible material, such as TPEE (polyester elastomer), TPU (polyurethane elastomer), fluoro rubber, and TPEA (polyamide elastomer), is filled in the lock button receptacle  21  and the unlock button receptacle  22  of the housing  11 . This forms pads  23  integrally with the lock button receptacle  21  and the unlock button receptacle  22 . The unlock button receptacle  22  is connected with the transponder retainer  18 . Thus, when the pads  23  are being formed, the flexible material is also filled in the transponder retainer  18 . As a result, the transponder  13  is covered by the flexible material when retained in the transponder retainer  18 .  
         [0024]    The transponder  13  incorporates an antenna coil, a transformer, a capacitor, and an IC (none of which are shown). In the transponder  13 , the antenna coil generates current when influenced by the magnetism of a magnetism generator (not shown), which is incorporated in the key cylinder of the vehicle. In accordance with the current, charge is stored in the capacitor via the transformer. When the voltage of the charged capacitor reaches a predetermined value, the transponder  13  transmits a transponder signal, which includes a predetermined ID code stored in the IC. The transponder signal of the transponder  13  is received by a receiver (not shown), which is incorporated in the key cylinder. The engine is started only when the ID code included in the transponder signal from the transponder  13  matches an ID stored in an engine control computer (e.g., electronic control unit). Since the transponder  13  uses electric energy that is stored in this manner, the transponder  13  does not have to have a power source that requires replacement, such as a battery.  
         [0025]    The formation of the pads  23  and the sealing of the transponder  13  will now be discussed with reference to FIGS.  3 ( a ) to  3 ( d ).  
         [0026]    In a state in which the transponder  13  is retained in the transponder retainer  18  (FIG. 3( a )), the housing  11  is set in a mold (not shown). Then, flexible material (indicated by the hatching lines in FIG. 3( b )) is filled in the lock button receptacle  21  and the unlock button receptacle  22  in the direction indicated by arrow X (the direction from the lock button receptacle  21  and the unlock button receptacle  22  toward the transmitter retainer  17 ). Since the unlock button receptacle  22  is connected with the transponder retainer  18 , the flexible material also fills the gap between the transponder retainer  18  and the transponder  13  from the unlock button receptacle  22 . Thus, as shown in FIG. 3( c ), the flexible material fills the transponder retainer  18 . This covers and seals the transponder  13  with the flexible material. In this manner, a seal  24  that seals the transponder  13  is formed integrally with the pad  23  in the same operation. Accordingly, the sealed transponder  13  is not visible from the outer side as shown in FIG. 3( d ). FIG. 3( d ) is a view of the housing  11  taken in the direction of arrow W in FIG. 1. When the transponder  13  is sealed in the housing  11 , the transmitter  12  is retained in the transmitter retainer  17 .  
         [0027]    The transmitter  12  is a module that transmits an ID signal requesting the closing of the locks when the pad  23  corresponding to the lock button receptacle  21  is pushed and transmits an ID signal requesting the opening of the locks when the pad  23  corresponding to the unlock button receptacle  22  is pushed. The ID signals include ID codes unique to the vehicle and codes for requesting the closing or opening of the locks.  
         [0028]    After the transmitter  12  and the transponder  13  are retained in the housing  11  of the remote control key  1 , the cover  14  is fitted to the stepped portion  16  of the housing  11 . Then, a screw  26  is inserted through a screw hole  25 , which extends through the cover  14 , and fastened with the threaded hole  15  of the housing  11 . This completes the remote control key  1 .  
         [0029]    When performing maintenance, such as replacement of the battery (not shown) of the transmitter  12  or replacement of the transmitter  12  with another transmitter  12 , the transmitter  12  is removed from the transmitter retainer  17 . In this case, the screw  26  is disengaged from the threaded hole  15 , and the cover  14  is taken off from the housing  11 . Then, force is applied to the pad  23  to remove the transmitter  12  from the transmitter retainer  17 . This facilitates maintenance of the transmitter  12 .  
         [0030]    The state of the remote control key  1  when the transponder  13  is removed will now be described in detail with reference to FIGS.  4 ( a ) to  4 ( c ).  
         [0031]    Referring to FIG. 4( a ), when removing the transponder  13  from the transponder retainer  18 , a shearing force is produced between the transponder retainer  18  and the transponder  13 . The shearing force acts to separate the transponder retainer  18  and the transponder  13 . Further, the shearing force exfoliates the flexible material around the transponder  13  from the transponder retainer  18 .  
         [0032]    As described above, the pad  23  and the transponder  13  are formed integrally with each other. Thus, referring to FIG. 4( b ), when a shearing force is produced between the transponder retainer  18  and the transponder  13 , a shearing force is also applied to part of the pad  23  that is exposed from the outer surface of the housing  11 . As a result, the outer surface of the pad  23  is partially sheared or deformed. A shearing or deformation mark  27  is left on the outer surface of the pad  23 . In other words, as shown in FIG. 4( c ), the removal of the transponder  13  leaves a mark  27  on the outer surface of the housing  11 .  
         [0033]    The remote control key  1  of the above embodiment has the advantages described below.  
         [0034]    (1) The transponder  13  is sealed by the same flexible material as that forming the pads  23  in the outer surface of the housing  11 . Thus, even if a third person opens the cover  14  of the remote control key  1  to steal the transponder  13 , the transponder  13  cannot be seen. Thus, it is difficult to confirm the position of the transponder  13  and remove the transponder  13 . This prevents theft of the transponder  13 .  
         [0035]    (2) The transponder  13  is sealed by the same flexible material as that forming the pads  23  in the outer surface of the housing  11 . Thus, there is no need to separately prepare seals. This reduces the manufacturing cost of the remote control key  1 .  
         [0036]    (3) The unlock button receptacle  22  is connected with the transponder retainer  18 . Thus, the flexible material enters the transponder retainer  18  from the unlock button receptacle  22 . As a result, the formation of the pads  23  and the sealing of the transponder  13  are performed simultaneously. This decreases the number of steps that are performed when manufacturing the remote control key  1  and reduces the manufacturing costs.  
         [0037]    (4) The pad  23  and the transponder  13  are formed integrally with each other. In addition, the pad  23  is formed in the surface of the housing  11 . Thus, when the transponder  13  is removed from the housing  11 , a mark  27  formed when the flexible material is sheared or deformed is left on the pad  23 . Accordingly, by looking at the mark  27  left on the outer surface of the housing  11 , the user would notice the theft of the transponder  13 . The pads  23  are formed from the flexible material. Thus, when the transponder  13  is stolen, the pads  23  are easily deformed and traces of the theft tend to remain in the pads  23 . This ensures that the user notices that the transponder  13  has been stolen.  
         [0038]    (5) The seal  24  is formed integrally with one of the pads  23 . Thus, the shearing force produced when removing the transponder  13  from the transponder retainer  18  is transmitted to the pad  23 . In addition, the unlock button receptacle  22  and the transponder retainer  18  are overlapped with each other. This improves the transmission of the shearing force. Thus, the traces produced when removing the transponder  13  tends to remain in the outer surface of the pad  23 . As a result, the mark  27  makes it further easier for the user to notice that the transponder  13  has been stolen.  
         [0039]    (6) The screw  26 , which is inserted through the screw hole  25  and fastened with the threaded hole  15 , integrates the housing  11  and the cover  14 . Thus, the remote control key  1  is easily disassembled by removing the screw  26  from the threaded hole  15 . Afterward, the transmitter  12  may be removed from the transmitter retainer  17 . Accordingly, maintenance of the transmitter  12  is facilitated.  
         [0040]    It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the present invention may be embodied in the following forms.  
         [0041]    The unlock button receptacle  22  and the transponder retainer  18  do not have to overlap each other. For example, as shown in FIG. 5( a ), the lock button receptacle  21  and the unlock button receptacle  22  may be formed in the bottom surface of the transmitter retainer  17 . Further, as shown in FIG. 5( b ), after the transponder  13  is retained in the transponder retainer  18 , a flexible material is filled in the lock button receptacle  21  and the unlock button receptacle  22  in the direction indicated by arrow R (the direction from the lock button receptacle  21  and the unlock button receptacle  22  toward the transmitter retainer  17 ) and in the transponder retainer  18  in the direction indicated by arrow S (the direction toward the transponder retainer  18 ). This forms the pads  23  and seals the transponder  13  as shown in FIG. 5( c ). In other words., the unlock button receptacle  22  and the transponder retainer  18  do not have to be connected with each other, and the formation of the pads  23  and the sealing of the transponder  13  may be performed separately if necessary.  
         [0042]    Further, in a remote control key  1  in which the unlock button receptacle  22  and the transponder retainer  18  do not overlap each other, a communication hole  30  may be formed between the transmitter retainer  17  and the transponder retainer  18 , as shown in FIG. 5( d ). In this case, the flexible material that enters the lock button receptacle  21  and the unlock button receptacle  22  flows through the communication hole  30  and fills the gaps between the transponder retainer  18  and the transponder  13 . As long as the formation of the pads  23  and the sealing of the transponder  13  are performed simultaneously, the relative positions of the lock button receptacle  21 , the unlock button receptacle  22 , and the transponder retainer  18  are not limited.  
         [0043]    In the remote control key  1  of the preferred embodiment, traces of removal of the transponder  13  are left on the outer surface of the pad  23 . However, the location of such traces is not limited to the outer surface of the pads  23 . For example, as shown in FIG. 6, the housing  11  and the cover  14  may be formed so that the seal  24  is partially exposed from the joining surfaces of the housing  11  and the cover  14  so that removal of the transponder  13  leaves traces on the exposed seal  24 . This prevents loosening of the screw  26  with the elasticity of the exposed seal  24 . Further, the housing  11  and the cover  14  may be formed so that the seal  24  is exposed along the entire periphery of the joining surfaces of the housing  11  and the cover  14 . In this case, the seal  24  functions as a packing and makes the remote control key  1  water resistant. The seal  24  does not have to be exposed from the joining surfaces of the housing  11  and the cover  14  and may be exposed anywhere on the outer surface of the remote control key  1 .  
         [0044]    In the preferred embodiment, the partition  19  is formed between the transmitter retainer  17  and the transponder retainer  18 . Thus, the partition  19  restricts the moving direction of the flexible material entering the transponder retainer  18 . As a result, the seal  24  is formed integrally with the pads  23 . However, the partition  19  does not necessarily have to be formed. If there is no partition  19 , for example, a mold may be used to restrict the direction in which the flexible material moves when the flexible material enters the transponder retainer  18 . This would also enable the formation of the pads  23  and the sealing of transponder  13  to be performed simultaneously. In other words, the structure of the housing  11  is not limited as long as the formation of the pads  23  and the sealing of the transponder  13  are performed simultaneously.  
         [0045]    The flexible material may be filled in the lock button receptacle  21  and the unlock button receptacle  22  in a direction from the transponder retainer  18  toward the lock button receptacle  21  and the unlock button receptacle  22  that is opposite to the direction indicated by arrow X in FIG. 3( b ) to seal the transponder  13  and form the pads  23 .  
         [0046]    In the preferred embodiment, the cover  14  is attached to the housing  11  by fastening the screw  26  with the threaded hole  15 . However, the threaded hole  15  and the screw  26  do not have to be used. For example, resin hooks that engage each other may be arranged in the housing  11  and the cover  14  to attach the cover  14  to the housing  11 . Since this would eliminate the need for the screw  26 , manufacturing costs for the remote control key  1  would be reduced.  
         [0047]    In the preferred embodiment, there is a gap between the entire periphery of the transponder  13  and the transponder retainer  18 . However, any side of the transponder  13  may be in contact with the transponder retainer  18 . This would enable the transponder  13  to be positioned in the transponder retainer  18 . This would also prevent displacement of the transponder  13  when sealing the transponder  13 .  
         [0048]    The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.