GB2314406A

GB2314406A - A vehicle lamp with cooling means.

Info

Publication number: GB2314406A
Application number: GB9712418A
Authority: GB
Inventors: Toichiro Shiozawa; Shinji Watanabe
Original assignee: Koito Manufacturing Co Ltd
Current assignee: Koito Manufacturing Co Ltd
Priority date: 1996-06-21
Filing date: 1997-06-13
Publication date: 1997-12-24
Anticipated expiration: 2017-06-13
Also published as: GB2314406B; GB9712418D0; JPH1012004A; JP3168511B2

Abstract

A vehicle lamp 1 has an upper ventilation hole 24 and a lower ventilation hole(s) 27 allowing air to circulate between the lamp chamber 31 and the lamp space 4B thus preventing clouding of the inner and outer lenses 29,3. The lamp chamber comprises a cup-shaped reflector 18 and inner lens 29. The ventilation holes are preferably located near the junction of reflector 18 and inner lens 29. The lamp space comprises a body 2 and outer lens 3. A light source 33 is mounted in the lamp space.

Description

VEHICLE LAMP The present invention relates to a vehicle lamp in which a light source positions in a lamp chamber defined by a reflector and an inner lens, and more particularly to a vehicle lamp of this type in which an air flow is positively formed thereby to prevent the inner lens and the outer lens from being clouded up.

There has been well known a conventional vehicle lamp in which a reflector is provided in the lamp space defined by the lamp body and an outer lens covering the opening of the lamp body, and an inner lens is provided in such a manner as to cover the opening of the reflector.

FIG. 9 shows an example of a vehicle lamp of this type. In FIG. 9, reference character k designates a lamp body of synthetic resin. The opening of the lamp body faces forwardly, and is covered with an outer lens d.

A reflector f of synthetic resin is arranged in the lamp space e which is defined by the lamp body b and the outer lens d, and the reflector f has an opening g which faces forwardly.

As shown in FIG. 9, an inner lens h having lens steps (not shown) covers the opening g of the reflector f. A light bulb i is provided with a glass ball i which is inserted into light-bulb inserting holes k and 1 which are formed in the lamp body b and the reflector f, respectively, and then positioned in the lamp chamber in which is defined by the inner lens h and the reflector f. The light bulb i has a flange n (described later). The light-bulb inserting hole 1 formed in the rear end wall of the reflector f is closed with the flange n of the light bulb ; that is, the lamp chamber in is completely closed up.

In the above-described vehicle lamp a, as indicated with the arrows in FIG. 9, the air heated by the light bulb i moves to the upper portion of the lamp chamber m and held there; that is, no air convection occurs in the lamp chamber m.

Furthermore, the reflector f and the inner lens h serve as heat sources, and therefore the air in the space above the reflector and the inner lens is high in temperature. Hence, in the lamp space e, too, which is defined by the lamp body k and the outer lens d, the air heated by those heat sources is moved to the upper portion of the lamp space e, and held there. Therefore, no air convection occurs in the lamp space. As a result, the inner lens h and the outer lens d are liable to be clouded.

In view of the foregoing, an object of the invention is to provide a vehicle lamp capable of forming air convection which can positively prevent the lens from being clouded.

The foregoing object of the invention has been achieved by a provision of a vehicle lamp in which, air ventilation holes to communicate a lamp chamber and a lamp space with each other are formed in the upper and lower portions of the junction of a reflector and an inner lens in such a manner that the air ventilation holes are located near the junction of the reflector and the inner lens.

Hence, in the vehicle lamp of the present invention, the air flow is formed as follows: That is, the air heated in the lamp chamber is discharged through the upper ventilation hole into the lamp space, and in the lamp space it is caused to flow down the inner surface of the outer lens while being cooled by the latter, so that the air thus cooled is caused to flow through the lower ventilation hole into the lamp chamber In the vehicle lamp according to another aspect of the invention, the ventilation hole formed in the upper portion of the junction of the reflector and the inner lens is located substantially above the optical axis thereof.

That is, with the vehicle lamp of the invention, the ventilation hole is formed in the part of the upper edge of the reflector which (part) is closest to the light source, namely, the light bulb. This feature allows the air in the lamp to flow with high efficiency.

In the vehicle lamp according to still another aspect of the present invention, the ventilation holes are each in the form of a slit which is extended along the junction of the reflector and the inner lens.

Hence, with the vehicle lamp of the invention, when viewed from the front, the ventilation holes are not noticeable.

In the accompanying drawings: FIGS. 1 through 7 shows an example of a vehicle lamp applied to a vehicle headlamp, which constitutes a first embodiment of the invention.

FIG. 1 is a front view of the vehicle headlamp; FIG. 2 is a sectional view taken along line II-II in FIG. 1; FIG. 3 is an enlarged sectional view taken along line 111-111 in FIG. 1; FIG. 4 is an enlarged sectional view taken along line IV-IV in FIG. 1; FiGS. 5 and 6 are a front view and a plan view, respectively, showing a reflector; FIG. 7 shows an inner lens. More specifically, Fig.

7A is a front view of the inner lens, and Fig. 7B is an enlarged sectional view taken along line B-B in Fig. 7A; FIG. 8 shows a second embodiment of the invention.

More specifically, FIG. 8 is an enlarged sectional view, corresponding to FIG. 3 showing the first embodiment; and FIG. 9 is a cross sectional view showing an example of a conventional vehicle lamp.

Preferred embodiments of a vehicle lamp according to the invention will now be described with reference to the accompanying drawings. Those embodiments shown in the drawings concern vehicle headlamps.

FIGS. 1 through 7 shows a first embodiment of the invention. In those figures, reference numeral 1 designates a vehicle headlamp. In the headlamp 1, a lamp body 2 having an opening which faces forwardly, and an outer lens 3 which covers the front opening of the lamp body 2, form a lamp space 4.

The lamp body 2 is made of synthetic resin, and has a recess 2a which is opened forwardly. The recess 2a has a lens setting portion 5 along the front opening edge, to set the outer lens 3. For this purpose, the lens setting portion 5 has a lens setting groove 5a which is opened forwardly.

The lamp body 2 is a combination of two portions 2A and 2B. A traveling beam reflecting means is arranged in an accommodating space 4A which is defined by the portion 2A and the part of the outer lens 3 which is confronted with the portion 2A. A low beam reflecting means is arranged in an accommodating space 4B which is defined by the portions 2B and the part of the outer lens 3 which is confronted with the portion 2B.

A cylindrical portion 7 is protruded backwardly from the rear wall 6 of the portion 2A. A protruded wall 8 is extended towards the center of the cylindrical portion 7 from the inner cylindrical surface of the latter 7, thus forming a substantially circular large rear opening 9.

A cylindrical portion 11 is protruded backwardly from the rear wall 10 of the portion 2B. A protruded wall 12 is extended towards the center of the cylindrical portion 11 from the inner cylindrical surface of the cylindrical portion 11, thus forming a substantially circular large rear opening 13.

The outer lens 3 is of synthetic resin, and is made up of a front portion 14 which covers the front of the abovedescribed recess 2a of the lamp body 2, and a surrounding wall portion 15 which are extended backwardly from the peripheral edge of the front portion 14; more specifically, the front portion 14 and the surrounding wall portion 15 are molded as one unit. The rear end 17 of the surrounding wall portion 15 of the outer lens 3 is engaged with the setting groove 5a of the lamp body 2 through a sealing agent 16: that is, the outer lens 3 is fixedly secured to the lamp body 2.

Reference numeral 18 designates a reflector of synthetic resin, which comprises a traveling beam reflecting portion 19, and a low beam reflecting portion 20 which are provided as one unit. The lamp body 2 supports the reflector 18 with the aid of an aiming mechanism (not shown) in such a manner that it is swingable both vertically and horizontally in the lamp space 4.

The traveling beam reflecting portion 19 includes an effective reflecting portion 19a having a predetermined reflecting surface, and a side portion l9b which is extended forwardly from the peripheral edge of the effective reflecting portion l9a. The effective reflecting portion 19a has a light bulb mounting hole 21 substantially at the center.

The low beam reflecting portion 20 includes an effective reflecting portion 20a having a predetermined reflecting surface, and a side portion 20b which is extended forwardly from the peripheral edge of the effective reflecting portion 20a.

The front end part of the upper surface portion 22 of the side portion 20b has recesses 23 which face backwardly (only part of the recesses shown in FIG. 4). The front edge of the upper surface portion 22 has cutouts 22a in front of the recesses 23. In the inner surface of the upper surface, between the wall having the recesses 23 and the cutouts 22a, ribs 23a are extended in a front-to-rear direction in such a manner that they are integral with the upper surface portion 22. The ribs 23a are adapted to abut against the upper edge of the inner lens (described later), to support the latter, and to reinforce the lower beam reflecting portion 20.

Reference character 24 designates an upper ventilation hole formed between the cutouts 22a of the upper surface portion of the reflecting portion 20. The upper ventilation hole 24 is located substantially above the optical axis, and it is in the form of a slit which is extended along the upper opening of the reflecting portion 20.

Reference character 25 designates the bottom portion of the side part 20b, and as shown in FIGS. 5 and 6, its front end part is lowered in height than the other parts, thus forming a step 25a. An engaging hole 26, which is rectangular in a plan view, is formed in front of the step 25a in such a manner that it is adjacent to the latter 25a (cf. FIG. 6). The engaging hole 26 is provided to support the lower edge of the inner lens (described later).

Reference numeral 27 designates lower ventilation holes formed on both sides of the aforementioned engaging hole 26 of the lower surface portion of the reflecting portion 20. The lower ventilation holes 27 are located behind the aforementioned step 25a and are each in the form of a slit extended along the step 25a.

As shown in FIG. 5, a light bulb mounting hole 28 is formed substantially at the center of the effective reflecting portion 20a. The light bulb mounting hole 28 is substantially in the form of the character "I" which is extended vertically.

Reference numeral 29 designates an inner lens which covers the front opening of the reflecting portion 20. The inner lens 29 is made of glass material. As shown in FIG.

7A, the inner lens 29 has a protrusion 29a which is extended downwardly from the middle of the lower edge, and has engaging grooves 29b which are formed in the upper edge to provide protrusions 29c which are extended forwardly. The distance between the protrusions 29c is substantially equal to the distance between the aforementioned cutouts 22a of the reflecting portion 20. Each of the engaging grooves 29b, as shown in FIG. 7B, has a flat portion 29 which is extended horizontally (in a right-to-left direction in the figure).

The inner lens 29 is coupled to the reflecting portion 20 as follows: First, the protrusion 29a of the inner lens 29 is inserted into the engaging hole 26 from above which is formed in the bottom portion 25 of the reflecting portion 20. Next, after the rear surface of the upper edge portion of the inner lens 39 is abutted against the ribs 23a of the reflecting portion 20, as shown in FIG. 4 both ends of each of clipshaped mounting members 30 (only one shown in FIG. 4) is engaged with the engaging grooves 29a of the inner lens 29 and the recesses 23 of the upper surface portion 22 of the reflecting portion 20, so as to clamp the protrusions 29c of the inner lens 29 and the front end portion of the reflecting portion 20 from front and rear. As a result, the inner lens 29 and the reflecting portion 20 form a lamp chamber 31.

Reference numeral 32 designates a traveling beam light bulb (cf. FIG. 2). The light bulb 32 is inserted through the rear opening 9 of the lamp.body 2 and the light bulb mounting hole 21 of the reflecting section 19, so that the glass ball of the light bulb 32 is set in the reflecting portion 21.

Reference numeral 33 designates a low beam light bulb. The light bulb 33 is inserted through the rear opening 13 of the lamp body 2 and through the light mounting hole 28 of the reflecting portion 20, so that the glass ball of the light bulb 33 is set in the lamp chamber 31.

In the lamp chamber 31, which is defined by the inner lens 29 and the reflector 18, the air heated by the low beam light bulb 33 is moved upwardly, and caused to flow through the upper ventilation hole 24 into the lamp space 4, thus reaching the upper portion of the inner surface of the outer lens 3. Since the outer lens 3 is cooled by the outside air, the air flowing out of the lamp chamber 31 is cooled by the outer lens 3. As a result, it flows down the outer lens 3, thus reaching the lower front end of the reflector 18.

On the other hand, in the lamp chamber 31, the air heated is discharged through the upper ventilation hole 24, so that the air in the lamp chamber 4 is caused to flow in it through the lower ventilation holes. As a result, the flow of air which moves upwardly in the lamp chamber 31, and the air flowing down the inner surface of the outer lens 3 form the convection of air.

Therefore, even if moisture enters the lamp space 4 or the lamp chamber 31, the aforementioned convection of air prevents the outer lens 3 and the inner lens 39 from being clouded. It is preferable that the rear wall of the lamp body 2 has a communication hole through which the lamp space 4 is communicated with the outside. In this case, the moisture in the lamp space 4 is discharged outside, which more positively prevents those lenses from being clouded.

FIG. 8 shows a second example of the vehicle lamp, which constitutes a second embodiment of the invention.

The second embodiment is different from the abovedescribed first embodiment only in that the ventilation holes are formed in the inner lens. FIG. 8 shows essential parts of the vehicle lamp. In FIG. 8, parts corresponding functionally to those already described with reference to the first embodiment are therefore designated by the same reference numerals or characters.

In FIG. 8, reference numeral 34 designates the inner lens of the vehicle lamp 1A. The inner lens 34 has an upper ventilation hole 35 at the middle of its upper portion in such a manner that it is located substantially above the optical axis. More specifically, the upper ventilation hole 35 is in the form of a slit which is extended along the upper edge of the inner lens 34. Furthermore, the inner lens 34 has lower ventilation holes 36 at both right and left end parts of the lower end portion of the inner lens. More specifically, the lower ventilation holes 36 are each in the form of a slit which is extended along the lower edge of the inner lens.

In the second embodiment, similarly as in the case of the first embodiment, the air heated in the lamp chamber 31 is caused to flow through the upper ventilation hole 35 into the lamp space 4, thus reaching the upper portion of the inner surface of the outer lens 3. As a result, the air is cooled by the outer lens 3, thus flowing down the inner surface of the outer lens 3 to the lower front end portion of the reflector 18.

On the other hand, in the lamp chamber 31, since the air heated is discharged through the upper ventilation hole 35, the air in the lamp space 4 is caused to flow thereinto through the lower ventilation holes 36 and 36. As a result, the flow of air which moves upwardly in the lamp chamber 31, and the air flowing down the inner surface of the outer lens 3 form the convection of air, whereby the outer lens 3 and the inner lens 29 are not clouded.

As was described above, according to the present invention, the air ventilation holes to communicate the lamp chamber and the lamp space with each other are formed in the upper and lower portion of the junction of the reflector and the inner lens in such a manner that the air ventilation holes are located near the junction of the reflector and the inner lens. Hence, the air heated in the lamp chamber is discharged through the upper ventilation hole into the lamp space, and in the lamp space the air is caused to flow down the inner surface of the outer lens, so that it is cooled, and then caused to flow into the lamp chamber through the lower ventilation holes.

In the vehicle lamp of the invention, further, the upper ventilation hole is located substantially above the optical axis. That is, with the vehicle lamp, the ventilation hole is formed in the part of the upper edge of the reflector which (part) is closest to the light source, namely, the light bulb. This feature allows the air in the lamp to flow with high efficiency.

Further, in the vehicle lamp of the invention, the ventilation holes are each in the form of a slit which is extended along the junction of the reflector and the inner lens. Hence, when viewed from the front, the ventilation holes are not noticeable.

Claims

1. A vehicle lamp comprising: a lamp receptacle formed with a cup-shaped reflector, a cover coupled to a front opening of said reflector and a lamp chamber defined by said reflector and said cover; a light source mounted on a bottom of said reflector, said light source projecting into said lamp chamber; at least one first ventilation hole formed in a first portion of said lamp receptacle upper than the position of said light source; and at least one second ventilation hole formed in a second portion of said lamp receptacle lower than the position of said light source.

2. The vehicle lamp according to claim 1, wherein said first portion of said lamp receptacle is an upper portion of a junction of said reflector and said cover, and said second portion of said lamp receptacle is a lower portion of the junction.

3. The vehicle lamp according to claim 2, wherein said first and second portions of said lamp receptacle are a part of said reflector.

4. The vehicle lamp according to claim 2, wherein said first and second portions of said lamp receptacle are a part of said cover.

5. The vehicle lamp according to claim 1, wherein said first ventilation hole is formed substantially above the optical axis of said light source.

6. The vehicle lamp according to claim 1, wherein each of said first and second ventilation holes is in the form of a slit extending along the junction of said reflector and said cover.

7. The vehicle lamp according to claim 2, wherein said first ventilation hole comprises one hole and said second ventilation hole comprises a couple of holes.

8. The vehicle lamp according to claim 1, further comprising: a lamp body having a front opening; an outer cover coupled to said front opening of said lamp body; and a lamp space defined by said lamp body and said outer cover, said lamp space accommodating therein said lamp receptacle.

9. The vehicle lamp according to claim 8, further comprising a through hole formed in a part of said lamp body.

10. The vehicle lamp according to claim 9, wherein said through hole is formed in a back wall of said lamp body.