Patent Publication Number: US-9851064-B2

Title: Vehicle lamp assembled with moisture-curing type adhesive

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority from Japanese Patent Application No. 2014-135952, filed on Jul. 1, 2014, with the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a vehicle lamp including a lens component attached to cover an opening of a lamp body. 
     BACKGROUND 
     In the related art, there is known a vehicle lamp that includes a light source within a lamp chamber defined by a lamp body having an opening and a lens component attached to cover the opening (see, e.g., Japanese Patent Laid-Open Publication No. 2010-267578). In the vehicle lamp, a hot melt seal material is introduced into a groove formed in the opening of the lamp body so that the lens component is fixed to the lamp body and the lamp chamber is sealed. 
     SUMMARY 
     The hot melt seal material is thermoplastic. Thus, the seal material may be fused, causing damage to the seal performance thereof when the temperature within the lamp chamber reaches a high temperature of 100° C. or more at the time of lighting. Therefore, attempts have recently been made to fix the lens component to the lamp body via a moisture curing type adhesive instead of the hot melt seal material. However, in the vehicle lamp as described above, there is room for improvement in productivity because a long time is required to cure the moisture curing type adhesive. 
     Accordingly, an object of the present disclosure is to provide a vehicle lamp in which the curing time of a moisture curing type adhesive is short. 
     A vehicle lamp according to the present disclosure is a vehicle lamp in which an insertion portion formed at a lens component made of a resin is inserted into a groove formed in a lamp body made of a resin and the lens component is fixed to the lamp body by a moisture curing type adhesive introduced into the groove. An inner surface of the groove in the cross section of the groove faces and is spaced apart from the insertion portion by a constant spacing in a range of 0.1 mm to 1.0 mm. The moisture curing type adhesive is introduced into the spacing. 
     With the vehicle lamp having the above-described configuration, since the spacing between the inner surface of the groove and the insertion portion is sufficiently narrow, the moisture curing type adhesive filled in the gap may be sufficiently cured by moisture contained in the resin of the lamp body or the lens component, which may result in reduced curing time. In a conventional structure, the curing by the moisture in the air absorbed from a surface exposed to the air was predominant. Thus, the curing time of the moisture curing type adhesive is reduced by adjusting the spacing between the inner surface of the groove and the insertion portion such that the curing by the moisture absorbed from the inner surface in contact with the resin becomes predominant. 
     In the vehicle lamp of the present disclosure, the inner surface of the groove may include a pair of side surfaces facing each other, and the insertion portion may include a leg portion extending in the depth direction of the groove and a protrusion protruding from the leg portion to one of the side surfaces of the groove. With the vehicle lamp having the above-described configuration, since the insertion portion may be placed in a stabilized posture in the groove by the leg portion and the protrusion, the positions of the lamp body and the lens component is hardly displaced during the curing of the moisture curing type adhesive. 
     In the vehicle lamp of the present disclosure, the protrusion may protrude along a bottom surface of the groove. With the vehicle lamp having the above-described configuration, the moisture curing type adhesive may be filled between the leg portion and one of the side surfaces and between the protrusion and the bottom surface such that the lamp body and the lens component may be bonded to each other on two intersecting surfaces. Thus, the lens component may be firmly fixed to the lamp body. 
     In the vehicle lamp of the present disclosure, the protrusion may be provided, at the tip end thereof, with an abutment portion extending along one of the side surface of the groove. With the vehicle lamp having the above-described configuration, the insertion portion may be placed in a stabilized posture in the groove by three portions including the leg portion, the protrusion, and the abutment portion. In addition, the lamp body and the lens component may be bonded to each other between the leg portion and the inner surface, between the protrusion and the inner surface, and between the abutment portion and the inner surface. Thus, high adhesion strength may be achieved. 
     In the vehicle lamp of the present disclosure, the protrusion may be a plate-shaped portion extending along a plane perpendicular to the depth direction of the groove. With the vehicle lamp having the above-described configuration, the protrusion may prevent the lens component from moving in relation to the lamp body in the in-plane direction perpendicular to the depth direction of the groove. 
     In the vehicle lamp of the present disclosure, the protrusion may be a plate-shaped portion extending along a plane perpendicular to the length direction of the groove. With the vehicle lamp having the above-described configuration, the protrusion may prevent the lens component from moving in relation to the lamp body in the in-plane direction perpendicular to the length direction of the groove. 
     In the vehicle lamp of the present disclosure, the insertion portion may include a leg portion extending in the depth direction of the groove, and the leg portion may be provided, above an opening of the groove, with a cover portion to cover at least a portion of the opening. With the vehicle lamp having the above-described configuration, the entry of impurities may be suppressed during the curing of the moisture curing type adhesive. In addition, the opening may be concealed. 
     According to the present disclosure, it is possible to provide a vehicle lamp in which the curing time of a moisture curing type adhesive is short. 
     The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a vertical sectional view illustrating a vehicle lamp according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a sectional perspective view illustrating a structure of a fixing position of a lamp body and a lens component in the vehicle lamp according to the exemplary embodiment of the present disclosure. 
         FIG. 3  is a sectional perspective view illustrating a structure of a fixing position of a lamp body and a lens component in a vehicle lamp according to a reference example. 
         FIG. 4  is a sectional perspective view illustrating a structure of a fixing position of a lamp body and a lens component according to Modification 1. 
         FIG. 5  is a sectional perspective view illustrating a structure of a fixing position of a lamp body and a lens component according to Modification 2. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawing, which form a part hereof. The illustrative embodiments described in the detailed description, drawing, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. 
     Hereinafter, an exemplary embodiment of a vehicle lamp according to the present disclosure will be described by way of example with reference to the accompanying drawings.  FIG. 1  is a vertical sectional view illustrating a vehicle lamp  10  according to an exemplary embodiment of the present disclosure. 
     As illustrated in  FIG. 1 , the vehicle lamp  10  according to the present exemplary embodiment is, for example, a headlamp that is provided on a front portion of a vehicle to illuminate the front side of the vehicle. The vehicle headlamp  10  includes a lamp body  11  having an open front side and a lens component  12  attached to cover the opening of the lamp body  11 . 
     A hermetically sealed lamp chamber S is defined inside the vehicle lamp  10  as the lens component  12  is bonded to the lamp body  11 . A light source  13  and a reflector  14  are arranged within the lamp chamber S. The light source  13  is placed in the lamp chamber S and the reflector  14  is placed behind the light source  13 . The lamp body  11  and the lens component  12  are fixed to each other at the outer circumferential edges of respective openings thereof. 
     In addition, in the present exemplary embodiment, the term “forward” refers to a direction from the light source  13  to the lens component  12  in the vehicle lamp  10  (the leftward direction in  FIG. 1 ), and the term “rearward” refers to a direction opposite to forward (the rightward direction in  FIG. 1 ). 
     The lamp body  11  is integrally formed of, for example, a synthetic resin. For example, the synthetic resin may be polycarbonate resin (PC resin), polycarbonate ABS resin (PC-ABS resin), or acryl resin (PMMA). The lens component  12  is formed of, for example, a transparent or semitransparent synthetic resin. For example, the synthetic resin may be polycarbonate resin (PC resin), polycarbonate ABS resin (PC-ABS resin), or acryl resin (PMMA). 
     The lens component  12  is an outer cover that allows light to pass therethrough. In addition, a lens step may be provided on the surface of the lens component  12  covering the opening of the lamp body  11  so as to condense or diffuse light from the light source  13 . 
     The light source  13  is placed in the lamp chamber S defined by the lamp body  11  and the lens component  12 . The light source  13  is electrically connected to a socket  21  fixed to the lamp body  11  and emits light upon receiving power supplied from a power source (not illustrated) through the socket  21 . 
     The reflector  14  has a concave surface recessed in an approximately parabolic form toward the front side, and a through-hole  22  is formed in the center of the concave surface to enable passage of the light source  13 . The reflector  14  is placed behind the light source  13  in the lamp chamber S and reflects light from the light source  13  forward (toward the lens component  12 ). 
     The lamp body  11  is formed with a groove  31  throughout the outer circumferential edge thereof. In addition, the lens component  12  includes a rearwardly protruding insertion portion  41  formed in the outer circumferential edge thereof. The insertion portion  41  is inserted into the groove  31  and fixed thereto by adhesive. 
       FIG. 2  is a sectional perspective view illustrating a structure of a fixing position of the lamp body  11  and the lens component  12  in the vehicle lamp  10  according to the exemplary embodiment of the present disclosure. 
     As illustrated in  FIG. 2 , an opening  35  of a main body portion  32  of the lamp body  11  is provided with a laterally protruding bottom wall  33  and a side wall  34  upright from the front end of the bottom wall  33 . In addition, in  FIG. 2 , the inner circumferential side (toward the lamp chamber S) of the lamp body  11  is the left side and the outer circumferential side of the lamp body  11  is the right side. 
     The forwardly opened groove  31  is formed along the outer circumferential edge of the opening of the main body portion  32 . The groove  31  is constituted with a side surface  32   a  of the main body portion  32  facing the outer circumference, an upper surface  33   a  of the bottom wall  33 , and a side surface  34   a  of the side wall  34  facing the inner circumference. The groove  31  includes the side surfaces  32   a  and  34   a  which have the same shape and are arranged to face each other, and the side surfaces  32   a  and  34   a  are configured as surfaces having the same shape in the depth direction of the groove  31 . The pair of side surfaces  32   a  and  34   a  face and are spaced apart from each other by a constant spacing W in a range of 1 mm to 5 mm. In the following description, the side surfaces  32   a  and  34   a  and the upper surface  33   a  may be collectively called an inner surface  31   a  of the groove  31 . 
     The insertion portion  41  has a leg portion  42  extending in the depth direction of the groove  31 . A plate-shaped protrusion  43  is formed at the tip end of the leg portion  42  of the insertion portion  41  and extends along a plane perpendicular to the depth direction of the groove  31 . The protrusion  43  is integrally formed to protrude from the leg portion  42  toward the side surface  34   a . The protrusion  43  protrudes along the upper surface  33   a.    
     A laterally protruding cover portion  44  is formed on the leg portion  42  of the insertion portion  41  above the protrusion  43 . The cover portion  44  protrudes above the opening  35  of the groove  31  in a state where the insertion portion  41  is inserted in the groove  31 . The cover portion  44  covers at least a portion of the opening  35  of the groove  31 . 
     The groove  31  is filled with a moisture curing type adhesive  51 . The insertion portion  41  is inserted into the groove  31  filled with the moisture curing type adhesive  51  and adhesively fixed to the groove  31  by the moisture curing type adhesive  51 . The moisture curing type adhesive  51  is an adhesive that is cured via reaction with a small amount of surrounding moisture and may acquire higher adhesion strength as an application thickness thereof decreases. When the groove  31  of the lamp body  11  and the insertion portion  41  of the lens component  12  are fixed to each other via the moisture curing type adhesive  51 , sealing efficiency between the outside and the inside of the lamp chamber S is acquired. 
     In this way, at a fixing position of the lamp body  11  and the lens component  12  which are fixed to each other via the moisture curing type adhesive  51 , when viewed in the cross section of the groove  31  (the cross section illustrated in  FIG. 2 ), at least a portion of the inner surface  31   a  of the groove  31  faces and is spaced apart from the insertion portion  41  by a constant spacing t in a range of 0.1 mm to 1.0 mm in which the moisture curing type adhesive  51  is filled. In the present exemplary embodiment, a gap t between the side surface  32   a  of the main body portion  32  and the leg portion  42  of the insertion portion  41  has a constant spacing in a range of 0.1 mm to 1.0 mm along the outer circumferential edge of the opening of the lamp body  11 . The moisture curing type adhesive  51  is filled in the gap. 
     In the related art, the groove  31  was formed with the relatively large opening  35  because a hot melt seal material that has widely been used at the fixing position of the lamp body  11  and the lens component  12  has relatively high viscosity. As such, the seal material has been efficiently injected into the groove  31  through an application nozzle (not illustrated). 
     Here, a reference example of a fixing structure of the lamp body  11  and the lens component  112  will be described.  FIG. 3  is a sectional perspective view illustrating a structure of a fixing position of the lamp body  11  and a lens component  112  in the vehicle lamp  10  according to the reference example. 
     As illustrated in  FIG. 3 , in the reference example, a structure of a conventional vehicle lamp is directly employed and, instead of the hot melt based seal material, the moisture curing type adhesive  51  is introduced to the gap. 
     Even in the reference example, the pair of side surfaces  32   a  and  34   a  constituting a portion of the inner surface  31   a  of the groove  31  face and are spaced apart from each other by a constant spacing W in a range of 1 mm to 5 mm. Meanwhile, in the reference example, no protrusion  143  is formed at a leg portion  142  of an insertion portion  141  of the lens component  112  and the leg portion  142  of the insertion portion  141  inserted in the groove  31  is located at the center of the width direction of the groove  31 . In addition, the moisture curing type adhesive  51  is filled in a gap between the inner surface  31   a  of the groove  31  and the periphery of the leg portion  142 . In this reference example, a gap t 1  between the side surface  32   a  and the leg portion  142  and a gap between the side surface  34   a  and the leg portion  142  is in a range of 2 mm to 3 mm. 
     Like the reference example, when the structure of the conventional vehicle lamp is directly employed and, instead of the hot melt seal material, the moisture curing type adhesive  51  is introduced to the gap, the long time is required until the moisture curing type adhesive  51  is cured. This is because, although the moisture curing type adhesive  51  filled in the gap is designed to be cured by absorbing moisture of air from a surface exposed to the air, moisture has difficulty in reaching the moisture curing type adhesive  51  deeply located in the groove  31  distant from the surface, thus causing a long time to be taken for curing. 
     Accordingly, the inventors have completed the present disclosure based on the fact that the moisture curing type adhesive  51  is cured by the moisture contained in the resin of the lamp body  11  as well. 
     With the vehicle lamp  10  according to the present disclosure, a spacing between the inner surface  31   a  of the groove  31  and the insertion portion  41  is sufficiently narrow. Thus, the moisture curing type adhesive  51  filled in the gap may be sufficiently cured by moisture contained in a resin of the lamp body  11  or the lens component  12 , which may reduce the curing time. In the conventional structure, curing by moisture in the air absorbed from a surface exposed to the air was predominant. Thus, the curing time of the moisture curing type adhesive  51  is reduced by adjusting the spacing t between the inner surface  31   a  of the groove  31  and the insertion portion  41  such that curing by the moisture absorbed from the inner surface in contact with the resin becomes predominant. 
     Since the gap between the inner surface  31   a  of the groove  31  and the insertion portion  41  is originally narrow, the moisture curing type adhesive  51  has a small volume, a short curing time, and high adhesion strength. Further, the manufacturing costs may be reduced. 
     The insertion portion  41  has the leg portion  42  extending in the depth direction of the groove  31  and the protrusion  43  protruding toward the side surface  34   a  of the groove  31  from the leg portion  42 . Thus, the insertion portion  41  may be placed in a stabilized posture in the groove  31  by the leg portion  42  and the protrusion  43 . Therefore, the positions of the lamp body  11  and the lens component  12  are hardly displaced during the curing of the moisture curing type adhesive  51 . 
     The protrusion  43  protrudes along the upper surface  33   a  of the bottom wall  33  in the groove  31 . As such, since the moisture curing type adhesive  51  may be filled between the leg portion  42  and the side surface  32   a  and between the protrusion  43  and the upper surface  33   a  so as to bond the lamp body  11  and the lens component  12  to each other at two intersecting surfaces, the lens component  12  may be firmly fixed to the lamp body  11 . 
     Since the protrusion  43  is a plate-shaped portion extending along a plane perpendicular to the depth direction of the groove  31 , the protrusion  43  may prevent the lens component  12  from moving in relation to the lamp body  11  in the in-plane direction perpendicular to the depth direction of the groove  31 . 
     The cover portion  44  is installed to the leg portion  42  above the opening  35  of the groove  31  to cover a portion of the opening  35 . Thus, entry of impurities may be suppressed during the curing of the moisture curing type adhesive  51 . In addition, the opening  35  may be concealed. 
     The inner surface of the groove  31  includes one pair of side surfaces  32   a  and  34   a  which face and are spaced apart from each other by a constant spacing W in a range of 1 mm to 5 mm. Thus, the moisture curing type adhesive  51  may be easily introduced into the groove  31 . In addition, the lamp body  11 , which is used in a vehicle lamp using the existing hot melt seal material, may be used. 
     Next, modifications of the present disclosure will be described, 
     (Modification 1) 
       FIG. 4  is a sectional perspective view illustrating a structure of a fixing position of the lamp body  11  and a lens component  212  according to Modification 1. 
     As illustrated in  FIG. 4 , at a fixing position of the lamp body  11  and the lens component  212  which are fixed to each other via the moisture curing type adhesive  51 , when viewed in the cross section of the groove  31  (the cross section illustrated in  FIG. 4 ), at least a portion of the inner surface  31   a  of the groove  31  faces and is spaced apart from an insertion portion  241  by a constant spacing t in a range of 0.1 mm to 1.0 mm in which the moisture curing type adhesive  51  is filled. In the present modification, a gap between the side surface  32   a  of the main body portion  32  and a leg portion  242  of the insertion portion  241  has a constant spacing t in a range of 0.1 mm to 1.0 mm along the outer circumferential edge of the opening of the lamp body  11 . The moisture curing type adhesive  51  is interposed in the gap. In addition, the inner surface of the groove  31  has the pair of side surfaces  32   a  and  34   a  which face and are spaced apart from each other by a constant spacing W in a range of 1 mm to 5 mm. 
     As illustrated in  FIG. 4 , in Modification 1, an abutment portion  245  is provided at the tip end of a protrusion  243  formed at the insertion portion  241 . The abutment portion  245  extends from the tip end of the protrusion  243  toward the opening  35  of the groove  31  along the side surface  34   a . In addition, a laterally curved locking portion  246  is formed at the end of the abutment portion  245 . 
     In Modification 1, when the insertion portion  241  provided with the abutment portion  245  is inserted into the groove  31 , the insertion portion  241  may be placed in a stabilized posture in the groove  31  by three portions including the leg portion  242 , the protrusion  243  and the abutment portion  245 . In addition, the lamp body  11  and the lens component  212  may be bonded to each other between the leg portion  242  and the inner surface  31   a , between the protrusion  243  and the inner surface  31   a , and between the abutment portion  245  and the inner surface  31   a , thereby achieving high adhesion strength. 
     In addition, when the locking portion  246  at the end of the abutment portion  245  comes into contact with the end surface of the side wall  34 , the insertion portion  241  may be more surely placed in a stabilized posture in the groove  31 , and positioning of the insertion portion  241  in the insertion direction with respect to the groove  31  may be performed. 
     (Modification 2) 
       FIG. 5  is a sectional perspective view illustrating a structure of a fixing position of the lamp body  11  and a lens component  312  according to Modification 2. 
     As illustrated in  FIG. 5 , at a fixing position of the lamp body  11  and the lens component  312  which are fixed to each other via the moisture curing type adhesive  51 , when viewed in the cross section of the groove  31  (the cross section illustrated in  FIG. 5 ), at least a portion of the inner surface  31   a  of the groove  31  faces and is spaced apart from an insertion portion  341  by a constant spacing t in a range of 0.1 mm to 1.0 mm in which the moisture curing type adhesive  51  is filled. In the present modification, a gap between the side surface  32   a  of the main body portion  32  and a leg portion  342  of the insertion portion  341  has a constant spacing t in a range of 0.1 mm to 1.0 mm along the outer circumferential edge of the opening of the lamp body  11 . The moisture curing type adhesive  51  is interposed in the gap. In addition, the inner surface of the groove  31  has one pair of side surfaces  32   a  and  34   a  which face and are spaced apart from each other by a constant spacing W in a range of 1 mm to 5 mm. 
     As illustrated in  FIG. 5 , in Modification 2, the leg portion  342  is formed with a protrusion  347 . The protrusion  347  is configured as a plate-shaped portion extending along a plane perpendicular to the length direction of the groove  31 . In addition, in Modification 2, the leg portion  342  is formed with a slope  342   a  near the opening  35  of the groove  31 . The slope  342   a  is inclined toward the bottom of the groove  31 , i.e. toward the inner circumference of the lamp body  11 . In Modification 2, a cover portion  344  formed on the leg portion  342  comes into contact with the end of the side wall  34  and the opening  35  of the groove  31  is blocked by the cover portion  344 . 
     In Modification 2, since the protrusion  347  extends along the plane perpendicular to the length direction of the groove  31 , the protrusion  347  may prevent the lens component  312  from moving in relation to the lamp body  11  in the in-plane direction perpendicular to the length direction of the groove  31 . 
     The present disclosure may be applied to any lamp tool, for example, a tail lamp or a fog lamp, without being limited to the headlamp so long as it is a vehicle lamp including a lamp body and a lens component. 
     From the foregoing, it will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.