GB2355347A

GB2355347A - Bayonet-mounted lighting device for a vehicle

Info

Publication number: GB2355347A
Application number: GB0024181A
Authority: GB
Inventors: Hironori Tsukamoto; Takayuki Yagi; Yoshiaki Aiso
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Koito Manufacturing Co Ltd
Priority date: 1999-10-12
Filing date: 2000-10-03
Publication date: 2001-04-18
Anticipated expiration: 2020-10-03
Also published as: FR2799528B1; GB0024181D0; JP2001110210A; DE10050607A1; GB2355347B; CN1292473A; JP3907883B2; KR100416425B1; DE10050607B4; CN1126899C; KR20010040046A; FR2799528A1

Abstract

A bulb socket (4) includes a cylindrical socket body (401) having L-shaped bayonet grooves (410) formed in an outer peripheral surface thereof. A tubular socket-mounting portion (21), in which the bulb socket (4) can be mounted, is formed on a reflector (2), and bayonet projections (22) for engagement in the respective fitting grooves (410) are formed on and project radially inwardly from the socket-mounting portion (21). When the bulb socket (4) is attached to the reflector (2), the bayonet projections (22) are fitted in the bayonet grooves (410), respectively, and therefore the bayonet projections (22) are not exposed, and the development of dark portions around the bulb socket (4) is suppressed, so that the appearance of the lighting device is improved. Alternatively the bulb socket may have bayonet projections and the mounting portion may have bayonet grooves (figure 8, not shown).

Description

2355347 LIGHTING DEVICE FOR A VEHICLE This invention relates to a lighting

device for a vehicle in which a bulb (electric bulb) is supported on a lighting device body or a reflector (hereinafter referred to as "reflector or the like") by the use of a bulb socket, and more particularly to such a vehicle lighting device in which the appearance of the bulb socket is improved.

In a lighting device for an automobile or the like, a bulb is mounted on a reflector or the like, and in order that the bulb can be exchanged, the bulb is mounted through a bulb socket releasably attached to the lighting device - A bayonet structure has heretofore been used in order that the bulb socket can be releasably attached to the reflector. Fig. 10 is a perspective view showing one example of a conventional bayonet structure. A bulb socket 4C includes a socket body 41 having a proximal end portion of a cylindrical shape, and a bulb support opening 44 for supporting a bulb 5 is formed in a front end surface of the socket body 41. A plurality of bayonet piece portions 42 project radially outwardly f rom. an outer peripheral surface of this cylindrical portion, and are circumf erentially spaced from one another. A flange 43 is formed on and projects radially outwardly from that portion of the outer peripheral surface of the cylindrical portion spaced a very small distance (equal to a wall thickness of a reflector 2 (described later)) from the bayonet piece portions 42 in a direction of the axis of the cylindrical portion, the f lange 43 exhibiting a spring nature in the axial direction. on the other hand, a socket mounting hole 24 of a circular shape for passing the socket body 41 of the bulb socket 4C therethrough is f ormed in a lighting device body (that is, the ref lector 2 in this example), and a plurality of notch grooves 25 for respectively passing the bayonet piece portions 42 therethrough are formed in an inner peripheral edge of this hole 24, and are circumferentially spaced from one another.

For attaching this bulb socket 4C to the reflector, the socket body 41- of the bulb socket 4C is inserted into the socket mounting hole 2 4 from the rear side of the reflector 2 as shown in Fig. 11A (which is a cross-sectional view), and then the bayonet piece portions 42 are passed respectively through the notch grooves 25, so that the flange 43 is held against the rear surface of the reflector 2. Then, the bulb socket 4C is angularly moved by a predetermined angle about the axis of the cylindrical portion, so that the inner peripheral edge portion of the socket mounting hole 24 is held between each bayonet piece portion 42 and the flange 43, and therefore the bulb 25 socket 4C is attached to the reflector by this holding force.

2 In this conventional bulb socket-mounting structure, the plurality of bayonet piece portions 42 project from the peripheral surface of the socket body 41 of the bulb socket 4C - Therefore, as shown in Fig. 1 1B (which is a view seen from 5 the front side of the lighting device), when the bulb socket 4C is attached to the reflector 2, the plurality of bayonet piece portions 42 are exposed to a reflecting surface of the reflector 2 (formed on the front surface thereof) at regions around the socket body 41. Therefore, when the lighting device is viewed from the front side thereof, those portions of the reflecting surface of the reflector 2 around the bulb socket 4C are concealed by the bayonet piece portions 42. Andbesides, recessed front end surfaces 41a of the socket body 41 are disposed at a position retracted from the reflecting surface 2a of the reflector 2, and therefore when the lighting device is viewed from the front side, the reflection of light is not ef f ected at these portions, so that these portions are seen as dark portions (stipple portions), and this detracts from the appearance of the lighting device. The reflecting surface of the ref lector 2 does not function as a ref lecting surf ace at the region of the socket mounting hole 24 at which the bulb socket 4C is mounted, and therefore the reflecting efficiency of the reflector 2 is inevitably lowered.

As shown in Fig. 12A (which is a cross-sectional view), 25 there has been proposed another construction in which part of 3 a rear wall of a reflector 2 is recessed into a tubular socket-mounting portion 21 much like a cylindrical container, and a socket mounting hole 24 and notch grooves 25 as described above for Fig. 10 are formed in a rear end of the tubular socket-mounting portion 21, and the above-mentioned bulb socket 4C is mounted in this socket mounting hole. In this construction, however, it is necessary that the inner diameter of the tubular socket-mounting portion 21 should be larger than a circle in which the outer surfaces of the bayonet piece portions 42 lie. Therefore, in this construction, when the lighting device is viewed from the front side, a dark portion (stipple portion) develops around the bulb socket 4C because of the formation of a gap between the tubular socket-mounting portion 21 and the socket body 41 as shown in Fig - 12B, and this detracts f rom the appearance. In this construction, also, the reflecting surface of the reflector 2 does not function as a reflecting surface at the region of the tubular socket-mounting portion 21 at which the bulb socket 4C is mounted, and therefore the reflecting efficiency of the reflector 2 is inevitably lowered.

It is an object of this invention to provide a lighting device for a vehicle in which the development of dark portions is suppressed when a bulb socket- is attached to a reflector 4 or the like, thereby preventing the appearance f rom being degraded, and besides the reflecting efficiency of the reflector can be enhanced.

According to one aspect of the invention, there is provided a lighting device for a vehicle wherein a bulb socket, supporting a bulb, is inserted into a socket mounting hole formed in a reflector or the like, and the bulb socket is turned about an axis thereof to be attached to the reflector or the like; and the bulb socket includes a cylindrical socket body having a fitting groove formed in an outer peripheral surface of the socket body, the f itting groove having an L-shape when viewed from a side of the socket body; and a f itting projection is formed on and projects radially inwardly from an inner surface of the socket mounting hole, and the fitting projection is engaged in the fitting groove when the bulb socket is inserted and turned. Preferably, the reflector has a tubular socket mounting portion having an inner diameter substantially equal to an outer diameter of the bulb socket, and the socket mounting hole is open to a bottom surf ace of the tubular 20 socket-mounting portion.

According to another aspect of the invention, there is provided a lighting device for a vehicle wherein a bulb socket, supporting a bulb, is inserted into a socket mounting hole formed in a reflector or the like, and the bulb socket is turned 25 about an axis thereof to be attached to the reflector or the like; CHARACTERIZED in that the bulb socket includes a cylindrical socket body, and radially outwardly-projecting fitting projections formed respectively on a plurality of portions of an outer peripheral surface of the socket body; and the ref lector or the like includes a tubular socket mounting portion, having an inner diameter substantially equal to an outer diameter of the bulb socket, and fitting grooves which are formed in an inner surface of the tubular socket-mounting portion, and can f it on the f itting projections, respectively.

Preferably, a front end surface of the socket body is disposed generally in a plane, in which an inner end of a reflecting surface of the reflector lies, when the bulb socket is attached to the ref lector or the like. Preferably, a f lange is formed on and projects radially outwardly from the outer peripheral surface of the socket body, and elastic contact piece portions are formed respectively at a plurality of portions of the flange spaced from one another in the circumferential direction, each of the elastic contact piece portions being formed as a result of formation of a pair of slits in the flange, and when the bulb socket is mounted in the socket mounting hole, the elastic contact piece portions are elastically contacted with a rear surface of the reflector or the like.

In the invention, when the bulb socket is attached to 25 the reflector or the like, the titting projections on the 6 reflector are fitted respectively in the fitting grooves in the bulb socket, or the fitting projections on the bulb socket are fitted respectively in the fitting grooves in the reflector or the like. Therefore, the fitting projections are not exposed, and dark portions will not be produced around the bulb socket by the fitting projections, and the appearance of the lighting device is improved. When the tubular socket-mounting portion, generally equal in size and shape to the bulb socket, is formed on the reflector or the like, a groove is not formed between the periphery of the bulb socket and the reflector or the like, and a dark portion will not be produced by this groovel and the appearance of the lighting device is further improved. And besides, the front end surface of the bulb socket is disposed generally in the plane in which the inner end of the reflecting surface of the reflector or the like lies, and with this construction this front end surface can serve as a reflecting surface, and the reflecting efficiency of the reflector or the like is enhanced. The flange and the elastic contact piece portions are elastically contacted with the reflector or the like, and by doing so, the reliability of attachment of the bulb socket can be enhanced.

Particular embodiments in accordance with the invention will now be described with reference to the accompanying drawings; in which: - Fig. 1 is a cross-sectional view of a first embodiment 25 of a lighting device of the invention.

7 Fig. 2 is an exploded perspective view of an important portion of the lighting device of Fig. 1.

Figs. 3A, 3B and 3C are respectively a front-elevational view, a sideelevational view and a rear view of a bulb socket 5 in the first embodiment of the invention.

Fig. 4 is a perspective view showing the manner of attaching the bulb socket of Fig. 3 to a reflector.

Fig. 5 is a view of the bulb socket of Fig. 3 as seen from the front side.

Fig. 6 is a perspective view of an important portion of a second embodiment of the invention.

Fig. 7 is a cross-sectional view showing the bulb socket of Fig. 6 in an attached condition.

Fig. 8 is a perspective view of an important portion of a third embodiment of the invention.

Figs. 9A and 9B are respectively a cross-sectional view and a sideelevational view, showing a bulb socket of Fig. 8 in an attached condition.

Fig. 10 is a perspective view explanatory of a conventional bulb socket having a bayonet structure.

Figs. 11A and 11b are respectively a cross-sectional view and a frontelevational view explanatory of problems with the conventional construction.

Figs. 12A and 12B are respectively a cross-sectional view 25 and a frontelevational view explanatory of problems with 8 0 another conventional construction.

[First Embodiment] Fig. I is a cross-sectional view showing the overall construction of a first embodiment of a lighting device 1 of the invention. This lighting device includes a reflector 2 molded of a resin, and an inner surface (that is, a front side) of this reflector serves as a reflecting surface. A lens 3 is attached to a front open portion 2b of the ref lector 2. The lens 3 has a seal leg portion 31 f ormed at an outer peripheral edge portion thereof. The seal leg portion 31 is fitted in a seal groove 20 formed at an outer peripheral edge of the reflector 2, and is fixed thereto by a sealant 30, so that a lighting chamber is defined by the reflector 2 and the lens 3. A tubular socket-mounting portion 21 is formed on the rear surface of the reflector 2, and a bulb socket 4 is releasably attached to the tubular socket-mounting portion 21 through a socket passage hole 12 open to the rear surface of the lighting device body 1. A bulb 5, serving as a light source, is supported on this bulb socket 4. The lighting device 1 is of a waterproof construction in which a sheet packing or the like (not shown) is held by ribs formed on the outer surface of the reflector, 9 and the bulb socket 4 is of the non-waterproof type.

Fig. 2 is a schematic, exploded perspective view showing the bulb socket 4 and a portion of the reflector 2, and Figs. 3A to 3C are a frontelevational view, a side-elevational view and a rear view of the bulb socket 4, respectively. The bulb socket 4 includes a socket body 401 of a generally cylindrical shape, and a bulb support opening 402 for receiving and supporting the bulb 5 is formed in a front end surface of the socket body 401 directed toward the front side of the lighting device, and a base portion 51 of the bulb 5 is received and held in this bulb support opening 402. In this embodiment, the bulb 5 comprises a so- called wedge base bulb in which electrodes 52, electrically connected to a self-contained filament, are mounted in the base portion 51 of a generally flattened shape. Therefore, the bulb support opening 402 is formed into an elongate shape, and contact electrodes 403 are mounted in this opening 402, and are connected to the electrodes 52 of the bulb 5 inserted in the bulb support opening 402. An operating piece portion 404 is formed perpendicularly on a rear surf ace of the socket body 4 0 1, and this operating piece portion 404 is used for turning the bulb socket 4 about the axis thereof.

Cords 405, connected respectively to the contact electrodes 403, extend outwardly from those portions of the rear surface of the socket body 401 disposed adjacent to the operating piece portion 404. - A circular flange 406 is formed integrally on and projects radially outwardly from an outer peripheral surface of the socket body 401 at the rear end thereof. Tongue-like elastic contact piece port-ions 407 are formed respectively at 5 a plurality of (two in this embodiment) portions of the flange 406 spaced substantially 1.80'0 from each other in the circumferential direction (that is, disposed on a diametrical line extending in a direction perpendicular to the direction of the length of the bulb support opening 402). Each of the elastic contact piece portions 407 is formed as a result of formation of a pair of parallel, radially-extending slits in the flange 406. These elastic contact piece portions 407 are elastically deformable in the direction of the axis of the socket body 401 because of an elastic nature of aresinmaterial of which the socket body is made. A projection 408 is formed at a distal end of each elastic contact piece portion 407, and projects slightly forwardly beyond the front surface of the flange 406. A notch, serving as an engagement groove 409, is formed in a portion of the peripheral edge of the flange 406, circumferentially spaced from the elastic contact piece portions 407, and extends a predetermined distance in the circumferential direction.

A pair of fitting grooves 410 are formed respectively in a plurality of (two in this embodiment) portions of the 25 peripheral surface- of the socket body 401 which are circumferentially spaced 900 from the two elastic contact piece portions 407, and are disposed adjacent respectively to the opposite ends of the bulb support opening 402, each of the f itting grooves 4 10 extending f rom the f ront end of the socket body 401 to the front surface of the flange 406. Each of the fitting grooves 410 includes an axial groove portion 411, extending in the direction of the axis of the socket body 401, and a circumferential groove portion 412 circumferentially extending perpendicularly from a rear end of the axial groove portion 411 in contiguous relation to the flange 406. Namely, the fitting groove 410, when viewed from the side of the socket body 401, has a reversed L-shape. The length of the circumferential groove portion 412 of the fitting groove 410 in the circumferential direction is slightly smaller than that of the engagement groove 409. Mold-removing holes 413, used to remove molds for respectively forming the circumferential groove portions 412 of the fitting grooves 410, are formed respectively through the relevant portions of the flange 406, in the axial direction, and with this construction the bulb socket 4 can be molded of a resin by a mold assembly without using any slider.

The tubular socket-mounting portion 21 of a cylindrical shape is f ormed on that portion of the rear surf ace of the reflector 2 to which the bulb socket 4 is to be attached. This tubular socket-mounting portion- 21 has an inner diameter 12 substantially equal to the outer diameter of the socket body 401 of the bulb socket 4, and also has an axial length substantially equal to the dimension from the f ront end surf ace of the socket body 401 to the flange 406. A pair of radially inwardly-projecting fitting projections 22 for fitting respectively into the pair of fitting grooves 410, formed in the socket body 401, are formed on the inner surface of the rear open end of the tubular socket- mounting portion 21. An engagement projection 23 is formed on a portion of the rear open end of the tubular socket-mounting portion 21, circumferentially spaced from the fitting projections 22, and projects in the direction of the axis of the tubular socket body, and the length of this engagement projection 23 in the circumferential direction is smaller than that of the engagement groove 409 in the socket body 401.

In the first embodiment of the above construction, for attaching the bulb socket 4 to the reflector 2 (see Fig. 4 which is a perspective view), the base portion 51 of the bulb 5 is inserted into the bulb support opening 402 in the bulb socket 4, so that the bulb 5 is supported by the bulb socket 4. In this condition, the bulb socket 4 is inserted into the tubular socket-mounting portion 21 from the rear side of the reflector 2. At this time, the pair of fitting grooves 410 in the socket body 401 are registered with the pair of fitting projections 25 22 of the tubular socket-mounting portion 21, respectively, 13 so that the bulb socket 4 can be inserted into the tubular socket- mounting portion 21 in the axial direction, and during this inserting operation, the axial groove portions 411 of the fitting grooves 410 are guided by the fitting projections 22, 5 respectively. At this time, the engagement groove 409 is registered with the engagement projection 23 so that the engagement projection 23 can fit into the engagement groove 409, and by thus positioning the two relative to each other in the circumferential direction, a bulb socket of a different 10 type (e.g. a single-type or a double-type bulb socket) is prevented from being erroneously attached to the reflector. Then, the bulb socket 4 is further inserted in the axial direction until the flange 40 6 is brought into contact with the rear end of the tubular socket-mounting portion 21, and 15 then the bulb socket 4 is turned or angularly moved about the axis thereof by a required angle corresponding to the length of the circumferential groove portions 412. As a result, the fitting projections 22 enter the circumferential groove portions 412 of the fitting grooves 4 10, respectively, and are 20 held in a f itted condition at or near to ends of the grooves 412, respectively. In this fitted condition, the projections 408, formed respectively at the distal ends of the elastic contact piece portions 407 provided at the flange 406 of the bulb socket 4, are elastically contacted with the rear surface 25 of the tubular socket-mounting portion 21, so that the elastic 14 contact piece portions 407 are slightly elastically deformed in the direction of the axis of the tubular socket body, and therefore the bulb socket 4 is urged outwardly in the axial direction by this elastic force. As a result, each fitting projection 22 is held against an axially-facing side surface of the corresponding circumferential groove portion 412, and the bulb socket 4 is supported in the tubular socket-mounting portion 21 by a frictional force developing as a result of contact of each fitting projection 22 with the axially-facing side surface.

When the bulb socket 4 is thus attached to the reflector 2, a gap between the bulb socket 4 and the tubular socketmounting portion 21 is extremely small since the outer diameter of the socket body 401 is substantially equal to the inner diameter of the tubular socket-mounting portion 21 as shown in Fig. 5 which shows the bulb socket 4 f rom the f ront side (that is, in a direction of arrow A of Fig. 1) And besides, since the dimension from the front end surface of the socket body 401 to the flange 406 is equal to the axial length of the tubular socket-mounting portion 21, the front end surface of the socket body 401 lies generally in a plane in which the inner end of the reflecting surface of the reflector 2 is disposed. Therefore, merely, the extremely-narrow gap and dark portions (as indicated by stipple portions in Fig. 5), produced respectively by the-fitting grooves 410, are seen between the periphery of the bulb socket 4 and the reflector 2 when the vicinity of the bulb socket 4 is viewed from the front side of the lighting device as shown in Fig. 5.

In this case, the fitting grooves 4 10 can be made smaller in size as compared with the bayonet piece portions of the conventional bayonet structure, and therefore those portions, which look dark because of the provision of the f itting grooves 410, can be almost ignored. Particularly in this embodiment, the fitting grooves 410 are provided adjacent to the opposite ends of the bulb support opening 402, respectively, and shadows of filament supports are produced at these regions, respectively, and therefore the dark portions, produced respectively by the f itting grooves 410, can be ignored because of the formation of the shadows of the filament supports. And besides, the fitting projections 22, formed on the tubular socket- mounting portion 21, are received respectively in the fitting grooves 410 in the bulb socket 4, and therefore will not be exposed to the f ront side, and any dark portion will not be produced by the fitting projections 22. Therefore, there is achieved the lighting device which has the good appearance and high quality. Furthermore, the circular front end surface 401a of the socket body 401 lies generally in the plane in which the inner end of the reflecting surface 2a of the reflector 2 is disposed, and a large portion of the tubular socket-mounting portion 21 is covered with the front end 16 surface 401a, and therefore this front end surface 401a can function as part of the ref lecting surf ace 2a of the ref lector 2 so as to enhance the ref lecting ef f iciency of the reflector 2.

[Second Embodiment] Fig. 6 is a perspective view of an important portion of a second embodiment of the invention, and Fig. 7 is a cross-sectional view of an important portion thereof in an assembled condition. In this second embodiment of the invention, there is used a bulb socket 4A of the waterproof type, and in order to achieve the waterproof ef f ect, any elastic contact piece portion is provided at a flange 406 of a socket body 401. There are not provided any mold-removing holes communicating respectively with fitting grooves 410 of an L-shape (when viewed from the side of the socket body 401) formed in an peripheral surface of the socket body 401.

Therefore, when molding the socket body 401, using a resin, the fitting grooves 410 are formed, for example, by setting sliders on a mold. An annular rubber packing 6 is fitted on the outer peripheral surface of the socket body 401, and is held against the surf ace of the f lange 406. Although not shown in the drawings, a waterproof seal is formed between each of two cords 405, extending outwardly from the socket body 401, and the socket body through a waterproof bushing. A front end surface 401a of the-socket body,-, in which the bulb support 17 opening 402 is formed, is formed into a concave surface corresponding in curvature to the reflecting surface 2a of the reflector 2.

In this second embodiment, when the bulb socket 4A is attached to the reflector 2 as shown in Fig. 7, merely, an extremely-narrow gap and dark portions, produced respectively by the fitting grooves 410, are seen between the periphery of the bulb socket 4A and the reflector 2 as described above for the first embodiment in Fig. 5, and therefore there is achieved the lighting device which has the good appearance and high quality. And besides, the circular front end surface 401a of the socket body 401 is formed into the concave surface corresponding in curvature to the reflecting surface 2a of the reflector 2, and therefore if a surface treatment is applied to the f ront end surf ace 40 la so that it can serve as a ref lecting surface, this front end surface 401a can function as part of the reflecting surface 2a of the reflector having the required curvature, so that the reflecting efficiency of the reflector 2 can be enhanced. Furthermore, a waterproof seal between the reflector 2 and the bulb socket 4A is formed by the rubber packing 6 interposed between a tubular socket-mounting portion 21 and the flange 406.

[Third Embodiment] Fig. 8 is an exploded perspective view of a portion of 25 a third embodiment of the invention. Figs. 9A and 9B are a 18 cross-sectional view and a side-elevational view of the third embodiment, respectively. Those portions, equivalentto those of the first and second embodiments, will be designated by identical reference numerals, respectively. In this third embodiment, radially outwardly-projecting fitting projections 420 are formed respectively on two diametrical ly-oppo site portions of a cylindrical outer peripheral surface of a socket body 401 of a bulb socket 4B.

The bulb socket 4B is of the waterproof type, and an annular rubber packing 6 is fitted on the outer peripheral surface of the socket body 40 1, and is held against a surface of a f lange 406. A tubular socket-mounting portion 21, formed on a reflector 2, has a larger wall thickness as compared with the above embodiments, and a pair of fitting grooves 24, corresponding respectively to the fitting projections 420 formed on the socket body 401, are formed respectively in two diametrical ly-oppo site portions of an inner peripheral surface of the tubular socket-mounting portion 21. Each of the fitting grooves 24 has such a width that the fitting projection 420 can pass through this fitting groove 24, and the fitting groove 24 has straight channel-shaped grooves 241 and 242 which extend respectively from outer and inner ends of the tubular socket-mounting portions 21 generally to a middle portion thereof in the direction of the axis thereof in such a manner that the two grooves 241 and 242 are 19 circumferentially offset with respect to each other by an amount equal to the width of the groove 24. Therefore, the fitting groove 24 has a crank- like configuration as a whole, and has a crank bent portion 243 disposed at the generally 5 middle portion of the tubular socket-mounting portion 21 in the direction of the axis thereof, the channel-shaped grooves 241 and 242 communicating with this crank bent portion 243. In this third embodiment, for attaching the bulb socket 4B to the reflector 2, a bulb 5 is supported on the bulb socket 10 4B, and in this condition the bulb socket 4B is inserted into the tubular socket-mounting portion 21 from the rear side of the ref lector 2. At this time, the pair of f itting projections 420 on the socket body 401 are registered with the pair of fitting grooves 24 in the tubular socket-mounting portion 21, 15 respectively. At this time, also, an engagement groove 409 is registered with an engagement projection 23 so that the engagement projection 23 can fit into the engagement groove 409, and by thus positioning the two relative to each other in the circumferential direction, a bulb socket of a different 20 type (e.g. a single-type or a double-type bulb socket) is prevented from beingerroneously attached to the reflector. Then, the bulb socket 4B is further inserted in the axial direction until the fitting projections 420 are brought into contact with the crank bent portions 243 of the fitting grooves 25 24, respectively, and then the bulb socket 4B is turned or angularly moved about the axis thereof by a required angle corresponding to the length of the fitting projections 42 0 in the circumferential direction. As a result, the f itting projections 420 advance along the crank bent portions 243 of 5 the fitting grooves 2 4, respectively, and are held in a fitted condition. In this fitted condition, the bulb socket 4B is urged outwardly in the axial direction by an elastic force of the rubber packing 6 interposed between the flange 406 and the tubular socketmounting portion 21. As a result, each fitting 10 projection 420 is held against an axially-facing side surface of the corresponding crank bent portion 243, and the bulb socket 4B is supported in the tubular socketmounting portion 21 by a frictional force developing as a result of contact of each fitting projection 420 with the axially-facing side surface.

In this third embodiment, when the bulb socket 4B is attached to the reflector 2 as shown in Fig. 9, merely, an extreme ly-n arrow gap and dark portions, produced respectively by the fitting grooves 2 4, are seen between the periphery of the bulb socket 4B and the reflector 2 as described above for 20 the f irst embodiment in Fig. 5, and therefore there is achieved the lighting device which has the good appearance and high quality. If a surface treatment is applied to a circular front end surface 401a of the socket body 401 so that it can serve as a reflecting surface, this front end surface 401a can 25 f unction as part of -a ref lecting-'surf ace 2a of the ref lector 21 2, so that the reflecting efficiency of the reflector 2 can be enhanced. A waterproof seal between the reflector 2 and the bulb socket 4B is formed by the rubber packing 6 interposed between the tubular socket-mounting portion 21 and the flange 406.

In the third embodiment, in order to obviate the need for sliders in a mold for molding the socket body 401, each of the fitting grooves 24 is formed into such a crank-like configuration that it has the crank bent portion 243 and the channel-shaped grooves 241 and 242 extending respectively from the outer and inner ends of the tubular socket-mounting portion 21. However, in the case where the fitting grooves 24 are formed, using sliders, each fitting groove 24 can be formed into an L-shape extending from the outer end of the tubular socket-mounting portion. When the fitting grooves are thus f ormed f these f itting grooves will not be exposed to the inner end of the tubular socket-mounting portion, and dark portions are prevented from being produced by the fitting grooves, and therefore will not be seen from the front side of the lighting device, so that the appearance can be further improved.

In the third embodiment, the bulb socket can be of the non-waterproof type, in which case elastic contact piece portions as described above for the first embodiment can be provided at the flange. The front end surface of the socket body of the bulb socket in the first and third embodiment can 22 be formed into a concave surface corresponding in curvature to the reflecting surface of the reflector as described above for the second embodiment.

In the first and second embodiments, although each of the f itting grooves 4 10, when viewed from the side of the socket body, has a reversed L-shape, it can have an opposite L-shape.

In the first embodiment, although the flange and the elastic contact piece portions are provided at the socket body, these are not always necessary, and any other suitable construction can be used in so far as it can provide the sense of resistance to the relative movement between each fitting projection and the corresponding fitting groove during the insertion of the bulb socket into the tubular socket-mounting portion. In the above embodiments, the tubular socket- mounting portion is formed on the reflector, and the bulb socket is mounted in this tubular socket-mounting portion. However, in the case where such a tubular socketmounting portion is not provided, at least the f itting projections are prevented from being exposed, and therefore will not produce dark portions which would detract from the appearance. In the above embodiments, although the bulb socket is attached to the reflector, the present invention can be applied also to the type of lighting device in which a bulb socket is attached to a lighting device body.

As described a-bove, in the -present invention, the bulb 23 socket includes the cylindrical socket body having the fitting grooves (having an L-shape when viewed from the side of the socket body) formed in the outer peripheral surface thereof, and the fitting projections for engagement in the respective 5 fitting grooves in the bulb socket are formed on and project radially inwardly from the inner surf ace of the socket mounting hole formed in the reflector or the like. Alternatively, the fitting projections are formed on the outer peripheral surface of the socket body of the bulb socket, and the L-shaped fitting 10 grooves for fitting respectively on the fitting projections are formed in the inner surface of the tubular socket-mounting portion formed in the reflector or the like. Therefore, when the bulb socket is attached to the reflector or the like, the fitting projections are fitted in the fitting grooves, 15 respectively, and therefore these fitting projections are not exposed, and dark portions will not be produced around the bulb socket by the fitting projections, and the appearance of the lighting device is improved. Particularly when the tubular socket-mounting portion, generally equal in size and shape to 20 the bulb socket, is formed on the ref lector or the like, a groove is not formed between the periphery of the bulb socket and the reflector or the like, and a dark portion will not be produced by this groove, and the appearance of the lighting device is further improved. And besides, the front end surface of the 25 bulb socket is disppsed generally in the plane in which the 24 inner end of the reflecting surface of the reflector or the like lies, and with this construction this f ront end surface can serve as a reflecting surface, and the reflecting ef f iciency of the ref lector or the like is enhanced. The f lange and the elastic contact piece portions are elastically contacted with the reflector or the like, and by doing so, the reliability of attachment of the bulb socket can be enhanced.

Claims

1. A lighting device for a vehicle comprising: a reflector in which a socket mounting hole is formed, said reflector has a fitting projection formed on and projects radially inwardly from an inner surface of said socket mounting hole; and a bulb socket for supporting a bulb and attached to said reflector by being inserted into said socket mounting hole and turned about an axis thereof, said bulb socket includes:

cylindrical socket body; and fitting groove formed in an outer peripheral surface of said socket body, said fitting groove having an L-shape when viewed from a side of said socket body, so that said fitting projection is engaged in said fitting groove when said bulb socket is inserted and turned.

2. A lighting device for a vehicle according to claim 1, wherein said ref lector has a. tubular socket mounting portion having an inner diameter substantially equal to an outer diameter of said bulb socket, and said socket mounting hole is open to a bottom surface of said tubular socket-mounting portion.

26

3. A lighting device for a vehicle according to claims 1 or 2, wherein said flange has mold-removing holes formed through respectively portions of said flange, corresponding to said fitting grooves, in an axial direction. 5

4. A lighting device for a vehicle comprising: a reflector having a tubular socket mounting portion including a socket mounting hole which is open to the a bottom surface of said tubular socket mounting portion, and a plurality of fitting grooves formed in an inner surface of said tubular socket mounting portion; and a bulb socket for supporting a bulb and attached to said reflector by being inserted into said socket mounting hole and turned about an axis thereof, said bulb socket includes:

a cylindrical socket body, a outer diameter of said cylindrical socket body is substantially equal to an inner diameter of said tubular socket mounting portion; and a plurality of fitting projections formed on and outwardly projecting from an outer peripheral surface of said socket body and respectively fitting on said fitting grooves.

5. A lighting device for a vehicle according to claim 4, wherein said - f itting grooves having crank-like 27 configuration when viewed from a side of said socket body

6. A lighting device for a vehicle according to any one of claims 1 to 5, wherein a front end surface of said cylindrical socket body and an inner surface of said reflector are generally in a plane when said bulb socket is attached to said reflector.

7. A lighting device for a vehicle according to any one of claims 1 to 6 wherein said bulb socket further includes a f lange formed on and projects radially outwardly from the outer peripheral surf ace of said socket body, and a plurality of elastic contact piece portions formed respectively at a plurality of portions of said flange spaced from one another in the circumferential direction, each of said elastic contact piece portion formed by a pair of slits in said flange, wherein said elastic contact piece portions are elastically contacted with a rear surface of said reflector when said bulb socket is mounted in said socket mounting hole.

8. A lighting device for a vehicle according to any one of claims I to 7, wherein said elastic contact piece portions has a plurality of projection fo=ed respectively at a distal ends of said elastic 'contact piece portions and 28 projecting forwardly beyond the front surface of said elastic contact piece portions.

9. A lighting device for a vehicle according to any one of claims 1 to 8, wherein said tubular socket mounting portion includes an engagement projection formed on a portion of a rear open end of said tubular socket mounting portion and projecting in a direction of the axis of said tubular socket body, wherein said f lange includes an engagement groove formed in a portion corresponding to said engagement projection and of a peripheral edge of said flange and extending a predetermined distance in the circumferential direction.

10. A -lighting device for a vehicle according to claim 9, wherein a length of said engagement projection in the circumferential direction is smaller than that of said engagement groove.

11. A lighting device for a vehicle according to any one of claims 1 to 10, wherein the front end surface of said bulb socket is formed into the concave surface corresponding in curvature to an inner surface of said refractor.

12. A lighti-ng device for a vehicle according to any 29 one of claims 1 to 11, wherein a surface treatment is applied to a front end surface of said socket body so as to serve as a reflecting surface.

13. A lighting device substantially as described with reference to Figures 1 to 9 of the accompanying drawings.