Abstract:
A vehicle lamp includes a housing, a transparent outer cover attached to the housing to form a lamp chamber together with the housing, a lamp unit disposed inside the lamp chamber to send light toward an outside of the lamp chamber through the outer cover, a sealing member arranged to seal a space between the housing and the outer cover, and an adhesive member disposed inside the lamp chamber in an at least partially exposed manner.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority from Japanese Patent Application No. 2009-261238 filed on Nov. 16, 2009, the entire content of which is incorporated herein by reference. 
       FIELD OF INVENTION 
       [0002]    The present invention relates to a vehicle lamp having a lamp unit disposed inside a lamp chamber formed by a housing and an outer cover. 
       DESCRIPTION OF RELATED ART 
       [0003]    A vehicle lamp generally includes a housing, an outer cover and a lamp unit. The housing is formed to have a box-like shape having an opening on one side, and the outer cover is attached to cover the opening of the housing. The lamp unit is disposed inside a lamp chamber which is formed by the housing and the outer cover. The outer cover is transparent so that the interior of the lamp chamber is visible from the outside. Therefore, with a view to keeping a good aesthetic condition of the interior of the lamp chamber, a gap between the housing and the outer cover of a related art vehicle lamp is filled with a seal material to prevent foreign particles from entering the lamp chamber (see, e.g., JP 2000-90724 A). 
         [0004]    However, it is not only the foreign particles that contaminate the interior of the lamp chamber. For example, a reflecting member such as a reflector of the lamp unit is generally deposited with aluminum or silver, and thus deposition residues may scatter inside the lamp chamber due to a vehicle vibration. Further, the lamp unit generally includes mechanical fastening parts such as a bolt and a nut as well as other metal parts. Thus, burrs of such parts of the lamp unit may chip off and also scatter inside the lamp chamber due to a vehicle vibration. Therefore, such internally-generated particles may also contaminate the interior of the lamp chamber. 
       BRIEF SUMMARY 
       [0005]    Illustrative aspects of the invention provide a vehicle lamp configured to prevent contamination of an interior of a lamp chamber. 
         [0006]    According to an illustrative aspect of the invention, a vehicle lamp includes a housing, a transparent outer cover attached to the housing to form a lamp chamber together with the housing, a lamp unit disposed inside the lamp chamber to send light toward an outside of the lamp chamber through the outer cover, a sealing member arranged to seal a space between the housing and the outer cover, and an adhesive member disposed inside the lamp chamber at least partially in an exposed manner. 
         [0007]    Other aspects and advantages of the invention will be apparent from the following description, the drawings and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a vertical sectional view of a vehicle lamp according to an exemplary embodiment of the invention; and 
           [0009]      FIG. 2  is a front view of the vehicle lamp. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Hereinafter, an exemplary embodiment of the present invention will be described in detail. However, the following exemplary embodiment does not limit the scope of the claimed invention, and all combinations of features of the exemplary embodiment are not necessarily required to address the problem described above. 
         [0011]    As illustrated in  FIGS. 1 and 2 , a vehicle lamp  10  according to the exemplary embodiment includes a housing  12 , an outer cover  14 , lamp units  16 ,  17 , and an extension  38 . The vehicle lamp  10  is configured as a headlamp which is mounted on each side of a front portion of a vehicle so that the lamp  10  is oriented in a forward direction X shown in  FIG. 1 . Right and left headlamps are symmetrically configured. Therefore, only one of the headlamps will be described below.  FIG. 1  is a sectional view of the headlamp  10  taken along a vertical plane including the optical axis of the lamp unit  16 . 
         [0012]    The housing  12  is formed to have a box-like shape having a front opening. The outer cover  14  is made of transparent resin or glass, and has a bowl shape. The edge portion of the outer cover  14  is attached to the housing  12  to cover the opening of the housing  12 , whereby a lamp chamber is formed as a region enclosed by the housing  12  and the outer cover  14 . 
         [0013]    The lamp units  16 ,  17  and the extension  38  are disposed inside the lamp chamber. The lamp units  16 ,  17  are both arranged such that irradiate a region in front of the headlamp  10 . More specifically, the lamp unit  16  produces a low beam and the lamp unit  17  produces a high beam. The lamp unit  17  may be configured in a similar manner as the lamp unit  16  except that a reflector and other components of the lamp unit  17  are configured and arranged to form a high beam light distribution pattern. Therefore, only the lamp unit  16  will be described in detail below, and description of the lamp unit  17  will be omitted. 
         [0014]    The lamp unit  16  is attached to the housing  12  via aiming screws  18 . The lower aiming screw  18  is configured such that it is rotated when a leveling actuator  20  is operated. That is, the optical axis of the lamp unit  16  can be moved in up and down directions by operating the leveling actuator  20 . 
         [0015]    The lamp unit  16  includes a projection lens  30 , a support member  32 , a reflector  34 , a bracket  36 , a light emitting module  40 , heat dissipating fins  42 , and a cooling fan  44 . The projection lens  30  is a plano-convex aspherical lens having a convex front surface and a flat rear surface. The projection lens  30  projects a light source image formed on the rear focal plane thereof toward the front of the headlamp  10  as an inverted image. The support member  32  supports the projection lens  30 . 
         [0016]    The light emitting module  40  includes a semiconductor light emitting device. According to the exemplary embodiment, the semiconductor light emitting device is a white light emitting diode (LED). However, the semiconductor light emitting device may be a laser diode. Further, the light emitting module  40  may not necessarily include a semiconductor light emitting device. For example, the light emitting module  40  may include an incandescent lamp with a filament or a discharge lamp. 
         [0017]    The reflector  34  reflects light from the light emitting module  40  to form the light source image on the rear focal plane of the projection lens  30 . Accordingly, the reflector  34  has a reflecting surface formed by mirror treatment such as aluminum deposition. As described above, the reflector  34  and the projection lens  30  function as optical components that collect and forwardly project the light emitted from the light emitting module  40 . The heat dissipating fins  42  are arranged on a rear surface of the bracket  36  to dissipate heat generated primarily by the light emitting module  40 . The cooling fan  44  is attached to the heat dissipating fins  42 , and sends air toward the heat dissipating fins  42  to enhance the heat dissipation from the heat dissipating fin  42 . 
         [0018]    The support member  32  includes a shade  32   a . The shade  32   a  shields a part of the light emitted from the light emitting module  40  and reflected by the reflector  34  so as to form a cutoff line of a low beam light distribution pattern ahead of the vehicle. The low beam light distribution pattern is well known and thus description thereof is omitted here. The extension  38  is provided so as to surround the projection lens  30 . The outer surface of the extension  38  is subjected to a mirror treatment such as aluminum deposition, and functions as a design surface that is visible from the outside. 
         [0019]    The housing  12  has a groove portion  12   f  along an opening edge of the housing  12 . The groove portion  12   f  is formed such that it is opened toward the front of the headlamp  10 , and a sealing member  50  fitted therein. The edge portion of the outer cover  14  is inserted into the groove portion  12   f  in which the sealing member  50  has been provided. In this manner, the sealing member  50  seals up a space between the housing  12  and the outer cover  14 . 
         [0020]    The sealing member  50  is made of a hot-melt adhesive. The hot-melt adhesive is a sealing material which melts when heated, but does not become completely solidified after being cooled. According to the exemplary embodiment, the hot-melt adhesive has viscosity in a range of about 10 Pa·S to 70 Pa·S and a viscosity variation rate of about 20% or lower. 
         [0021]    More specifically, the sealing member  50  is a gelled hot-melt adhesive. The hot-melt adhesive includes a styrene thermoplastic elastomer (SEBS), butyl rubber or the like as a base polymer and additives including a tackifier made of resin or the like, a wax made of a polypropylene or the like, an anti-oxidizing agent, a pigment, and a plasticizing agent made of a low molecular polymer or the like. 
         [0022]    To provide the sealing member  50 , a molten hot-melt adhesive may be automatically supplied into the groove portion  12   f  of the housing  12  using an automatic supply apparatus. The housing  12  with the hot-melt adhesive filled in the groove portion  12   f  is then cooled until the hot-melt adhesive is gelled. Next, the edge portion of the opening of the outer cover  14  is inserted into the groove portion  12   f  of the housing  12 , and the outer cover  14  is attached to the housing  12 . 
         [0023]    As described above, the reflecting surface of the reflector  34  and the extension  38  are mirror treated by aluminum deposition or the like. Such vapor deposition processed components may scatter deposition residues inside the lamp chamber due to a vibration of the vehicle or the like. Further, inside the lamp chamber, there are mechanical fastening parts such as a bolt and a nut, and other metal parts. Such mechanical parts may also scatter particles such as chipped off burrs inside the lamp chamber. When such particles stick onto, for example, the design surface of the extension  38 , the soiled surface is visible from the outside, which leads to deterioration of an aesthetic aspect of the headlamp  10 . 
         [0024]    In order to address this problem, the headlamp  10  according to the exemplary embodiment includes an adhesive member  52  arranged inside the lamp chamber. The adhesive member  52  has an adherence property that catches the internally-generated particles describes above so that the particles adhere to the adhesive member  52 . The adhesive member  52  is made of the same material as the sealing member  50 . Therefore, the adhesive member  52  can be provided on the inner surface of the lamp chamber during the process of automatically filling the groove portion  12   f  with the hot-met adhesive for the sealing member  50 . 
         [0025]    More specifically, an additional teaching may be input to a robot (i.e., the automatic supply apparatus), to fill a recessed portion  12   e  of the housing  12  with the hot-met adhesive to provide the adhesive member  52  in the same process as filling the groove portion  12   f  with the hot-met adhesive for the sealing member  50 . According to this method, the adhesive member  52  can be provided productively with low cost. 
         [0026]    The adhesive member  52  is arranged on a portion of the inner surface of the housing  12  adjacent to the groove portion  12   f . According to this structure, a wall of the groove portion  12   f  configured to receive the sealing member  50  can be used to restrict an area in which the hot-melt adhesive for the adhesive member  52  is provided. The housing  12  further includes a rib  12   d  adjacent to the portion of the inner surface where the adhesive member  52  is arranged. The rib  12   d  is arranged to extend substantially parallel to a direction along which the groove portion  12   f  extends. Owing to this, even when the headlamp is turned upside down for example during the manufacturing process or the delivering process, the adhesive member  52  is blocked from moving. Accordingly, the design surface is prevented from being soiled by the adhesive member  52 . 
         [0027]    More specifically, the inner surface of the housing  12  includes a bottom portion  12   a  and a vertical surface  12   b  vertically extending down from the front end of the bottom portion  12   a . The housing  12  further includes a horizontal surface  12   c  arranged to horizontally extend toward the front from the lower end of the vertical surface  12   b . The horizontal surface  12   c  forms a part of the wall that defines the groove portion  12   f . The rib  12   b  is provided protrude toward the front from the vertical surface  12   b . The recessed portion  12   e , which is opened toward the front, is defined by the rib  12   b , the vertical surface  12   b  and the horizontal surface  12   c . The adhesive member  52  is provided in this recessed portion  12   e . That is, the rib  12   d  provides the recessed portion  12   e  to easily and reliably arrange the adhesive member  52 . 
         [0028]    The rib  12   d  extends from a region below the lamp unit  16  to a region below the lamp unit  17 . Therefore, as shown in  FIG. 2 , the adhesive member  52  is arranged to extend in a substantially entire region below the lamp units  16 ,  17  along the width direction of the lamp units  16 ,  17 . However, the adhesive member  52  may not necessarily be provided in this manner, and may be partially arranged in a region below the lamp unit  16  or the lamp unit  17 . 
         [0029]    As shown in  FIG. 1 , the groove portion  12   f  and the recessed portion  12   e  are both opened toward the front of the headlamp  10 . Therefore, during the process for filling the groove portion  12   f  with the hot-melt adhesive for the sealing member  50 , the hot-melt adhesive for the adhesive member  52  can be easily and reliably provided in the recessed portion  12   e.    
         [0030]    The bottom portion  38   a  of the extension  38  is formed on substantially the same level as the bottom portion  12   a  of the housing  12 . The bottom portion  38   a  of the extension  38  and the bottom portion  12   a  of the housing  12  form a receiving surface  58  which extends substantially in the horizontal direction in a region below the lamp unit  16 . The rear end  38   b  of the extension  38  is spaced slightly away from the front end of the rib  12   b . In other words, the receiving surface  58  is formed with a gap  58   a  which penetrates the receiving surface  58  in the vertical direction. The adhesive member  52  is arranged directly below the gap  58   a.    
         [0031]    The internally-generated particles described above drops onto the receiving surface  58  from, for example, the lamp unit  16 . Because the gap  58   a  is formed in the receiving surface  58  and the adhesive member  52  is arranged directly below the gap  58   a , the particles efficiently caught by the adhesive member  52  and adhere to the adhesive member  52 . The receiving surface  58  may be provided separately from the housing  12  and the extension  38 . In this case as well, a gap  58   a  may also be formed in the receiving surface, and the adhesive member  52  may be disposed directly below the gap. 
         [0032]    According to the exemplary embodiment described above, the adhesive member  52  is disposed inside the lamp chamber of the headlamp  10 . However, the adhesive member  52  may be disposed inside a lamp chamber of other types of vehicle lamps. 
         [0033]    While the present invention has been described with reference to a certain exemplary embodiment thereof, the scope of the present invention is not limited to the exemplary embodiment described above, and it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the scope of the present invention as defined by the appended claims.