JP2009087620A - Headlight for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve heat radiation performance in a headlight for a vehicle while preventing the enlargement of a device and an increase of weight. <P>SOLUTION: The headlight for the vehicle comprises a light source stored in a housing, a heat dissipation member arranged outside the housing, and a flexible heat-conductive member connected with the light source at one end and connected to the heat dissipation member at the other end. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle headlight. In detail, it is related with the improvement of the thermal radiation mechanism of the headlight for vehicles.

  Vehicle headlights require light with high illuminance, and the amount of heat generated increases accordingly, so countermeasures against heat are important. One of the heat countermeasures of the light emitting device is one using a heat pipe. For example, Patent Document 1 discloses a light emitting device including a heat pipe in which a heat input portion is connected to a light source in a housing and a heat radiating portion is connected to a heat sink outside the housing. In this light emitting device, heat generated by the light source is released outside the housing by a heat pipe. Patent Document 2 discloses a light emitting device that uses a loop heat pipe to emit heat from a light source to the outside of the housing.

JP 2006-107875 A JP 2006-164967 A

In the vehicle headlight, it is necessary to adjust the angle of the optical axis. However, if the heat pipe disclosed in the above document is adopted, the position of each member is fixed. The installation angle must be changed. Such a change in the installation angle is complicated. In addition, it is difficult to adjust the angle of the optical axis after being assembled once.
On the other hand, heat pipes generally have a pipe-like structure with capillaries (wicks) inside, and a small amount of working fluid (alternative chlorofluorocarbon, water, etc.) is vacuum-sealed inside the heat pipe. The use of such a heat pipe has contributed to an increase in size and weight of the apparatus.
Accordingly, an object of the present invention is to improve heat dissipation and facilitate angle adjustment of an optical axis in a vehicle headlight. Another object is to improve heat dissipation while preventing an increase in size and weight of the device.

In order to achieve at least one of the above problems, the present invention provides a vehicle headlight described below. That is,
A light source housed in a housing;
A heat dissipating member disposed outside the housing;
A flexible heat conducting member that conducts heat of the light source to the heat radiating member;
It is set as the headlight for vehicles provided with.

  In the vehicle headlight of the present invention, the heat of the light source propagates to the heat radiating member provided outside the housing via the heat conducting member, and is released outside the housing. Since the heat conducting member is flexible, the heat conductor can be deformed following the change in the installation angle of the light source. This makes it easy to adjust the angle of the optical axis by changing the installation angle of the light source even after assembly.

  Hereinafter, components in the light emitting device of the present invention will be described in detail. (Light source) Although the kind of light source is not specifically limited, It is preferable that it is an LED lamp. This is because the LED lamp is small and has advantages such as resistance to vibration and impact. The type of the LED lamp is not particularly limited, and various types such as a shell type and an SMD type can be adopted. The emission color of the LED lamp is not particularly limited, and an LED lamp having a desired emission color such as white, blue, red, or green can be used. A plurality of LED lamps may be used as the light source.

It is preferable to use an LED lamp using a mounting substrate having high thermal conductivity such as a metal such as copper or aluminum or a ceramic. This is because the heat of the light source can be efficiently propagated to the heat conducting member. The light source is housed in the housing. The housing may further include a reflector (reflector) and an outer lens.
It is preferable that one end of a heat conductive member to be described later is connected to the pedestal using a heat conductive pedestal to which the light source is attached, and the other end of the heat conductive member is connected to a heat radiating member to be described later. This is because the light source is stably attached and the heat of the light source efficiently propagates to the heat conducting member and is released from the heat radiating member. As the material of the pedestal, metals such as copper and aluminum, ceramics, and the like can be used. When an LED lamp is used as the light source, the pedestal is preferably in contact with substantially the entire back surface of the LED chip mounting substrate. This is to more efficiently propagate the heat of the light source to the heat conducting member.

(Heat dissipation member)
The heat dissipation member used in the present invention is provided outside the housing. The configuration of the heat dissipation member is not particularly limited, and for example, a heat sink including a plurality of metal fins having high thermal conductivity can be used. The size of the heat dissipation member can be determined in consideration of the required heat capacity. Further, a member having a large heat capacity such as a vehicle frame or a vehicle radiator may be used as the heat radiating member of the present invention.

(Heat conduction member)
The heat conducting member conducts heat from the light source to the heat radiating member. The heat conducting member is flexible, and the material is preferably a graphite sheet or the like. This is because the graphite sheet has high thermal conductivity, is flexible, and is easy to handle. Here, “flexible” means a property that is flexible and can be easily bent, bent, or stretched. Since the heat conducting member is flexible, a part of the heat conducting member is deformed such as curved, bent, twisted, stretched or contracted following the change of the installation angle of the light source. The heat conducting member is attached in a state of being slackened between the light source and the heat radiating member. Here, the “sagging state” means that the length from the contact point with the light source to the contact point with the heat dissipation member is longer than the distance from the light source to the heat dissipation member, and at least a part of the heat conduction member. Refers to the state of bending. By sagging the heat conducting member in this manner, unnecessary tension (tension) is prevented from being applied to the heat conducting member when the heat conducting member is deformed following the change in the installation angle of the light source. Thereby, the heat conduction member is prevented from being damaged or dropped off. Although the shape of a heat conductive member is not specifically limited, It is preferable to provide sufficient length in order to provide the above-mentioned slack. A plurality of heat conducting members may be used and provided at a plurality of locations. For example, it is good also as providing in two places using two graphite sheets. The number of heat conductive members used can be determined according to the material of the heat conductive member to be used, its thermal conductivity, and the type of light source. The thermal conductivity of the graphite sheet is about 400 W / mk to 1700 W / mk in the plane direction. For example, one graphite sheet can be used for three LED lamps.

In one embodiment of the present invention, an optical axis adjustment mechanism that changes the installation angle of the light source according to the steering angle of the vehicle handle is provided. By the optical axis adjustment mechanism, the headlight actively illuminates the traveling direction of the vehicle, and the visibility of the driver is improved. A known mechanism can be adopted as the optical axis adjustment mechanism in the present invention. For example, the light source or the pedestal to which the light source is attached is tilted or rotated in a predetermined direction by a motor driving force according to the steering angle of the vehicle handle. It can be a mechanism.
Examples of the present invention will be described below.

A perspective view of a vehicle headlight 1 according to an embodiment of the present invention is shown in FIG. 1, and a longitudinal sectional view of the vehicle headlight 1 is shown in FIG. As shown in FIG. 1, the headlight 1 includes an outer lens 2 and a light source unit 3. As shown in FIG. 2, the light source unit 3, the graphite sheet 4, and the optical axis adjusting mechanism 5 are accommodated in the housing 20. On the other hand, a heat sink 6 is provided on the back side of the housing 20. The light source unit 3 includes an LED lamp 31, a pedestal 32, a reflector 33, and a lens 34. The light source 21 is a surface-mounted white light emitting LED lamp. The pedestal 32 is made of a metal having high thermal conductivity such as aluminum or copper in consideration of heat dissipation, and the LED lamp 31 is disposed on the upper surface of the pedestal 32. The reflector 33 is provided on the light emission side of the LED lamp 31, and the shape thereof is a dome shape, and the diameter of the reflector 33 is increased and opened on the outer lens 2 side. The inner side surface of the reflector 33 is a reflecting surface. The lens 34 is provided on the outer lens 2 side of the reflector 33. The light from the LED lamp 31 is reflected by the reflector 33, passes through the lens 34, and travels to the outer lens 2 side.

The LED lamp 31, the pedestal 32, the graphite sheet 4, the optical axis adjusting mechanism 5 and the heat sink 6 are extracted, and a perspective view thereof is shown in FIG. The heat sink 6 is made of aluminum, and includes a cubic base 61 and a plurality of fins 62 erected on the base 61 in the vertical direction, as shown in FIG. The heat sink 6 is provided through the opening on the back surface of the housing 20 so that the bottom surface 63 of the base 61 is exposed inside the housing 20 and the fins 62 are exposed behind the housing 20 (see FIG. 2). A waterproof packing (not shown) is attached between the opening on the back surface of the housing 20 and the heat sink 6 to prevent water and the like from entering the housing 20. Further, the entire edge of the outer lens 2 is welded to the housing 20. As a result, the inside of the housing 20 is kept waterproof.
The graphite sheet 4 has a sheet shape having a length of about 50 mm and a width of 50 mm. One end of the graphite sheet 4 is attached to an extending portion 321 extending downward from the pedestal 32 with a bolt 42 so as to be sandwiched between the aluminum plate 41 and the pedestal 32 (see FIG. 2). The graphite sheet 4 is attached to the extending portion 321 of the pedestal 32 so that the flat portion 40 of the graphite sheet 4 is parallel to the axial direction of the rotating shaft 51 of the optical axis adjusting mechanism 5 described later (FIG. 3). reference). On the other hand, the other end of the graphite sheet 4 is attached to the bottom surface 63 of the heat sink 6 with bolts 44 so as to be sandwiched between the aluminum plate 43 and the bottom surface 63 as shown in FIG. The graphite sheet 4 is attached to the extended portion 321 of the pedestal 32 and the bottom surface 63 of the heat sink 6 in a sufficiently slackened state. In addition, the surface of the graphite sheet 4 is coated with a coating for preventing scratches (for example, coated with a polyimide resin). In addition, you may attach the graphite sheet 4 to the side surface by making the base 32 thick. A plurality of graphite sheets 4 may be used. In this case, if one end of the graphite sheet 4 on the heat sink 6 side is attached at different positions on the left and right and up and down of the bottom surface 63 of the heat sink 6, the heat dissipation effect is improved.

  The optical axis adjusting mechanism 5 includes a rotating shaft 51 and a motor driving unit 52. The upper end of the rotating shaft 51 is connected to the pedestal 32, and the lower end of the rotating shaft 51 is connected to the motor drive unit 52. The motor drive unit 52 is connected to a control circuit (not shown), and is controlled to be driven according to the steering angle of the vehicle handle. The vehicle headlight 1 is provided with an aiming screw 7, which also allows the angle adjustment of the optical axis 31 of the light source unit 3 from the outside of the housing 20.

  Next, the heat radiation mode of the vehicle headlight 1 will be described. The LED lamp 31 is attached to a metal pedestal 32 having a high thermal conductivity, and the heat of the LED lamp 31 propagates to the pedestal 32. The heat propagated to the pedestal 32 propagates to one end of the graphite sheet 4 attached to the extending portion 321 of the pedestal 32 and further propagates from the other end of the graphite sheet 4 to the heat sink 6. The heat transmitted to the heat sink 6 is released to the outside of the housing 20 from the fins 62 exposed to the outside of the housing 20. Since the graphite sheet 4 has a high thermal conductivity, the heat of the LED lamp 31 is efficiently propagated to the heat sink 6 and exhibits a high heat dissipation effect. Since the graphite sheet 4 is a thin sheet and is lightweight, the entire apparatus is configured to be small and light. Furthermore, since the strength of the graphite sheet 4 is enhanced by coating (for example, coating of polyimide resin), handling is easy and attachment workability is also high.

  Next, the angle adjustment of the optical axis 35 of the vehicle headlight 1 will be described. First, when the vehicle headlight 1 is mounted, the installation angle of the light source unit 3 is changed by rotating the aiming screw 7 and pushing the light source unit 3 toward the outer lens 2 or pulling it toward the rear side of the housing 20 to change the optical axis 35. The angle is adjusted. On the other hand, after the attachment, the motor drive unit 52 rotates the rotary shaft 51 in the axial direction by the optical axis adjusting mechanism 5 according to the steering angle of the vehicle handle. The upper end of the rotation shaft 51 is connected to the pedestal 32, and the rotation angle of the rotation shaft 51 changes the installation angle of the entire light source unit 3. Thereby, the angle adjustment of the optical axis 35 is performed. In the above angle adjustment of the optical axis 35, the graphite sheet 4 is deformed as the installation angle of the light source unit 3 is changed. Since the graphite sheet 4 is flexible and is installed in a sufficiently slack state, when the installation angle of the light source unit 3 is changed, the graphite sheet 4 is deformed following this and the graphite sheet 4 itself or other It is possible to easily adjust the angle of the optical axis 35 without applying excessive tension to the member and without changing the installation position of the entire vehicle headlight 1. As described above, in the vehicle headlight 1, by adjusting the angle of the optical axis 35 in accordance with the steering angle of the vehicle handle, the traveling direction of the vehicle can be actively illuminated to improve the driver's visibility. it can.

  The vehicle headlight of the present invention can be used for various vehicle headlights.

1 is a perspective view of a vehicle headlight 1 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the vehicle headlight 1. FIG. 3 is a partial perspective view of the vehicle headlight 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Headlight 2 Outer lens 20 Housing 3 Light source unit 31 LED lamp 32 Base 33 Reflector 34 Lens 35 Light source 4 Graphite sheet 41, 43 Aluminum plate 42, 44 Bolt 5 Optical axis adjustment mechanism 51 Rotating shaft 52 Motor drive part 6 Heat sink 61 Base 62 Fin 7 Aiming Screw

Claims (5)

A light source housed in a housing;
A heat dissipating member disposed outside the housing;
A flexible heat conducting member that conducts heat of the light source to the heat radiating member;
A vehicle headlight comprising:   The vehicle headlight according to claim 1, wherein the heat conducting member is made of a graphite sheet. A heat conductive pedestal to which the light source is attached;
One end of the heat conducting member is connected to the pedestal, and the other end of the heat conducting member is connected to the heat radiating member.
The vehicle headlight according to claim 1, wherein the vehicle headlight is provided.   The vehicle headlight according to any one of claims 1 to 3, further comprising an optical axis adjustment mechanism that changes an installation angle of the light source according to a steering angle of a vehicle handle.   The vehicle headlight according to any one of claims 1 to 4, wherein the light source is an LED lamp.

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