JP2013045674A - Vehicular lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular lamp capable of improving operating stability by controlling temperature rise of an electric circuit in a circuit case by heat shielding and heat radiation.SOLUTION: The vehicular lamp has at least a light source housed in a lamp chamber demarcated by a housing and an outer lens to cover its opening and a circuit board 11, on which an electric circuit for driving and controlling the light source is mounted, is housed in the circuit case 8 attached to the rear face of the housing. The circuit case 8 is constructed of a resin and a heat radiation plate 13 is adhered tightly to the circuit board 11 housed in the circuit case 8 through a heat radiation sheet 12. Further, the circuit board 11 and the heat radiation plate 13 are attached to the circuit case 8 by joint tightening.

Description

  The present invention relates to a vehicular lamp in which a circuit board on which an electric circuit for driving and controlling a light source is mounted is housed in a circuit case attached to the back surface of a housing.

  Vehicle lamps such as headlamps arranged on the left and right of the front part of the vehicle are configured such that at least a light source is accommodated in a lamp chamber defined by a housing and an outer lens that covers the opening. A circuit board on which an electric circuit for driving and controlling the light source is mounted is attached.

  In such a vehicular lamp, since the electrical components of the circuit board generate heat by lighting, it is necessary to release the heat to the surroundings by heat dissipation to suppress the temperature rise of the electrical components and to ensure stable operation of the electrical circuit. is there. For this reason, conventionally, a configuration has been adopted in which a circuit case is formed by aluminium die casting having high thermal conductivity and the circuit case functions as a heat sink (see, for example, Patent Document 1).

Japanese Patent No. 4727701

  By the way, a configuration in which a circuit case molded by aumi die casting or the like functions as a heat sink is, for example, in an electric vehicle equipped with an electric motor as a drive source, because the temperature of the circuit case is higher than the ambient temperature. Can be used as a heat sink, and the heat generated in the electric circuit accommodated therein can be dissipated from the circuit case to the surroundings.

  However, in a vehicle that uses an engine that is a high heat source as a drive source, the engine has a higher temperature than the circuit case, so heat from the engine is transmitted to the electric circuit through the circuit case, and the electric circuit is heated. There is a problem that the operation stability is impaired.

  The present invention has been made in view of the above problems, and a purpose of the present invention is to provide a vehicular lamp that can suppress an increase in the temperature of an electric circuit in a circuit case by heat insulation and heat dissipation and can improve the operation stability thereof. Is to provide.

  In order to achieve the above object, the invention according to claim 1 is configured such that at least a light source is accommodated in a lamp chamber defined by a housing and an outer lens covering the opening, and an electric circuit for driving and controlling the light source is mounted. In a vehicular lamp comprising a circuit board accommodated in a circuit case attached to the back surface of the housing, the circuit case is made of resin, and a heat dissipation sheet is provided on the circuit board accommodated in the circuit case. It is characterized in that the heat sink is closely attached.

  According to a second aspect of the present invention, in the first aspect of the present invention, the circuit board and the heat sink are attached to the circuit case by fastening together.

  According to the first aspect of the present invention, since the circuit case is made of the resin having a lower heat transfer coefficient than that of the metal and having a high heat insulating property, for example, heat from the outside of the engine or the like can be blocked by the circuit case. The heat generated by the electric circuit itself in the circuit case is conducted from the heat radiating sheet to the heat radiating plate, and is radiated from the heat radiating plate to the surroundings. Therefore, the temperature rise of the electric circuit accommodated in the circuit case is suppressed by heat insulation by the circuit case and heat radiation from the heat radiating plate, and the operation stability is improved.

  According to the invention described in claim 2, since the circuit board and the heat sink are attached to the circuit case by fastening together, the assembly of the circuit board and the heat sink can be improved, and the fastener components such as screws can be used. The cost can be reduced by reducing the number of points.

1 is a front view of a vehicular lamp according to the present invention. It is a rear view of the vehicle lamp which concerns on this invention. It is an external view (figure of the arrow A direction of FIG. 4) of the circuit case of the vehicle lamp which concerns on this invention. It is a side view of the circuit case of the vehicle lamp which concerns on this invention. It is an inner surface figure (the figure of the arrow B direction of FIG. 4) of the circuit case of the vehicle lamp which concerns on this invention. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is a disassembled perspective view which shows the internal structure of the circuit case of the vehicle lamp which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 is a front view of a vehicular lamp according to the present invention, FIG. 2 is a rear view of the vehicular lamp, FIG. 3 is an external view of a circuit case of the vehicular lamp (a view in the direction of arrow A in FIG. 4), 4 is a side view of the circuit case, FIG. 5 is an inner view of the circuit case (a view in the direction of arrow B in FIG. 4), FIG. 6 is a cross-sectional view taken along the line CC in FIG. DD sectional drawing, FIG. 8 is an exploded perspective view which shows the internal structure of a circuit case.

  A vehicular lamp 1 according to the present embodiment is a combination type headlamp provided on the left and right of a front portion of a vehicle. As shown in FIG. 1, a vehicular lamp 1 includes a housing 2 and a transparent outer lens 3 covering its front opening. A low lamp 4, a high beam lamp 5, a position lamp 6 and a turn signal lamp 7 are accommodated in the defined lamp chamber. Since the left and right headlamps 1 have the same configuration on the left and right, only one headlamp 1 will be illustrated and described below.

  By the way, as shown in FIG. 2, the circuit case 8 is attached to the upper part of the back surface of the housing 2 by tightening the surrounding three places with screws 9. Here, the circuit case 8 is integrally formed of a resin such as PBT / PET having a lower thermal conductivity than that of a metal and having a high heat insulating property. As shown in FIGS. A bottom cylindrical storage portion 8A is formed, and a plate-like flange portion 8B is formed around it. Mounting brackets 8a are integrally projected at three locations on the outer periphery of the flange portion 8B. Each mounting bracket 8a has a circular hole 10 through which the screw 9 (see FIG. 2) is inserted. ing. Further, as shown in FIGS. 6 and 7, bosses 8 b are projected from three locations on the inner surface of the accommodating portion 8 </ b> A of the circuit case 8.

  Thus, as shown in FIGS. 5 to 8, the circuit board 11, the heat radiating sheet 12, the heat radiating plate 13, and the shielding cover 14 are accommodated inside the accommodating portion 8 </ b> A of the circuit case 8.

  The circuit board 11 is formed into a disk shape with ceramic or the like having high thermal conductivity and high electrical insulation, and this includes an electric circuit for driving and controlling the light source of the low beam lamp 4 accommodated in the lamp chamber. A circuit (not shown) is mounted. Further, as shown in FIGS. 5 and 8, a connector 15 is attached to a side portion of one surface of the circuit board 11 (the front side of FIGS. 5 and 8). Is formed with a circular hole 17 through which the screw 16 is inserted.

  The heat radiating sheet 12 is made of a material having high heat conductivity, and the heat radiating plate 13 is made of aluminum having high heat conductivity. Here, as shown in FIG. 8, mounting brackets 13 a erected on the front side of FIG. 8 are formed on the upper and lower sides of the heat radiating plate 13 by cutting and raising, Similarly, a rectangular plate-like close contact portion 13b that rises to the near side in FIG. 8 is formed by cutting and raising. A circular hole 18 is formed in each mounting bracket 13 a of the heat radiating plate 13.

  The shielding cover 14 is for shielding an electric circuit (not shown) mounted on the circuit board 11 from noise, and is formed into a rectangular box shape by sheet metal. Mounting brackets 14a (only two are shown in FIG. 8) are integrally formed at three locations on the outer periphery of the shielding cover 14 (three locations corresponding to the circular holes 17 formed on the circuit board 11). Each mounting bracket 14a has a long hole-like screw insertion hole 19 formed therein.

  Thus, the heat radiating plate 13, the heat radiating sheet 12, the circuit board 11, and the shielding cover 14 are incorporated in the housing portion 8 </ b> A of the circuit case 8, but the circuit board 11 and the heat radiating plate 13 sandwich the heat radiating sheet 12 therebetween. Overlaid. At this time, as shown in FIG. 7, the heat dissipation sheet 12 is in close contact with one surface of the circuit board 11 (the lower surface in FIG. 7) and the surface of the contact portion 13 b of the heat dissipation plate 13. The positions of the circular holes 18 formed in the upper and lower mounting brackets 13 a of the heat sink 13 are adjusted so as to coincide with the upper and lower circular holes 17 formed on the outer periphery of the circuit board 11.

  From the above state, the shielding cover 14 is aligned with the circuit board 11, the mounting brackets 14 a formed at three locations on the outer periphery thereof are brought into close contact with the circuit board 11, and the screw insertion holes 19 formed on each mounting bracket 14 a Align with the circular holes 17 formed at three places. In this state, the three screws 16 are passed through the three screw insertion holes 19 of the shielding cover 14 and the three circular holes 17 of the circuit board 11, and the upper and lower two screws 16 are inserted into the upper and lower two circles of the heat sink 13. The three screws 16 are screwed into the three bosses 8b of the circuit case 8 as shown in FIGS. 5 to 7 through the holes 18, so that the shielding cover 14, the circuit board 11 and the heat radiating plate 13 are fastened together. It is attached to the case 8. When the shielding cover 14, the circuit board 11, and the heat radiating plate 13 are attached to the circuit case 8 by tightening, the heat radiated between the circuit board 11 and the heat radiating plate 13 as shown in FIG. 7. The sheet 12 is in close contact with one surface of the circuit board 11 and the surface of the close contact portion 13 b of the heat sink 13.

  The circuit case 8 in which the shielding cover 14, the circuit board 11, and the heat radiating plate 13 are incorporated is provided with a circular hole 10 (see FIGS. 3 and 3) of each mounting bracket 8 a that protrudes from three locations on the outer periphery of the flange portion 8 B. As shown in FIG. 2, it is attached to the back surface of the housing 2 by tightening a total of three screws 9 that are respectively inserted into (5).

  Thus, the headlamp 1 formed by incorporating the circuit board 11 and the heat radiating plate 13 in the circuit case 8 attached to the back surface of the housing 2 as described above, and interposing the heat radiating sheet 12 therebetween, Although it is arrange | positioned at the front left and right of the vehicle which arrange | positions the engine as a drive source in an engine room, in the headlamp 1 which concerns on this invention, a heat transfer rate is lower than a metal, and is heat insulation. Since the circuit case 8 is made of high resin, the heat from the engine can be blocked by the circuit case 8, and conduction of heat from the outside to the circuit board 11 in the circuit case 8 is suppressed. Further, the heat generated by the electric circuit itself in the circuit case 8 is conducted from the heat radiating sheet 12 to the heat radiating plate 13 and is radiated from the heat radiating plate 13 made of aluminum having high thermal conductivity to the surroundings. The heat radiated from the heat radiating plate 13 to the surroundings is dissipated into the lamp chamber, and the heat flowing into the lamp chamber is radiated to the atmosphere via the outer lens 3 and the like.

  Therefore, according to the headlamp 1 of the present invention, the electric circuit mounted on the circuit board 11 accommodated in the circuit case 8 is insulated from the heat shielding by the resin circuit case 8 and from the heat sink 13 made of aluminum. The increase in temperature is suppressed by heat dissipation, and the operation stability is improved.

  In the present embodiment, since the shielding cover 14, the circuit board 11, and the heat radiating plate 13 are attached to the circuit case 8 by fastening together with screws 16, The attachment performance is improved, and the number of parts of the fastener such as the screw 16 is reduced, so that the cost of the headlamp 1 can be reduced.

  In the above, the embodiment in which the present invention is applied to a headlamp has been described. However, the present invention is naturally applicable to any other vehicular lamp other than the headlamp. .

1 Headlamp (vehicle lamp)
2 Housing 3 Outer Lens 4 Low Beam Lamp 5 High Beam Lamp 6 Position Lamp 7 Turn Signal Lamp 8 Circuit Case 8A Circuit Case Storage 8B Circuit Case Flange 8a Circuit Case Mounting Bracket 8b Circuit Case Boss 9 Screw 10 Circuit Case 11 circuit board 12 heat sink 13 heat sink 13a heat sink mounting bracket 13b heat sink close contact 14 shield cover 14a shield cover mounting bracket 15 connector 16 screw 17 circuit board circular hole 18 heat sink circular hole 19 Shield cover screw insertion hole

Claims (2)

A circuit board, in which at least a light source is accommodated in a lamp chamber defined by an outer lens that covers the housing and its opening, and an electric circuit that drives and controls the light source is mounted in a circuit case attached to the rear surface of the housing. In the vehicular lamp that is housed,
A vehicle lamp characterized in that the circuit case is made of resin, and a heat radiating plate is closely attached to the circuit board accommodated in the circuit case via a heat radiating sheet. The vehicular lamp according to claim 1, wherein the circuit board and the heat sink are attached to the circuit case by fastening together.

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