JP6423378B2 - In-vehicle antenna device and heat dissipation method for in-vehicle antenna device - Google Patents

Description

  The present invention relates to a vehicle-mounted antenna device and a heat dissipation method for a vehicle-mounted antenna device.

  There is an in-vehicle antenna that is used by being attached to the outside of a vehicle. In-vehicle antennas used to be pillar antennas that are attached to window pillars. In recent years, roof antennas that are attached to the roof of a vehicle have become mainstream. A typical roof antenna is of a sealed type in which a communication unit is sealed in a casing. Many of such sealed roof antennas have a streamlined outer shape in order to reduce air resistance during travel. Since its shape resembles a shark or dolphin fin, it is also called a shark fin antenna or a dolphin antenna (registered trademark).

  Since the sealed roof antenna as described above is attached to the roof of the vehicle, the inside of the housing is likely to become hot due to the influence of solar radiation in fine weather. In addition, when the vehicle is stopped, the airflow around the antenna is not cooled, so that the inside of the housing is likely to be hotter. If the temperature inside the housing becomes high, the performance of the mounted electronic circuit may be degraded, leading to a decrease in antenna performance.

  In addition, in recent years, multi-functionalization is being advanced by adding functions such as inter-vehicle communication and road-to-vehicle communication to a sealed roof antenna. Due to such multi-functionalization, heat generation from the electronic components mounted in the housing increases, and the electronic circuit is likely to become higher in temperature. For this reason, the cooling of the electronic circuit mounted on the hermetic roof antenna is a major issue. Various methods for solving this problem have been tried.

  For example, Patent Document 1 discloses a technique for facilitating movement of heat generated in a wireless communication circuit to a casing and releasing the heat to the outside through the casing. In this technique, a heat conduction path having a higher thermal conductivity than air is formed between the wireless communication circuit sealed in the housing and the housing. Specifically, a method of providing a thick portion inside the housing and directly contacting the thick portion and the wireless communication circuit, a method of connecting the housing inner wall and the wireless communication circuit with a heat conducting member, etc. It is shown.

JP 2014-050031 A

  However, the technique of Patent Document 1 has a problem that heat dissipation is insufficient. One cause is that the thermal conductivity of the housing itself is low. In order for the wireless communication circuit in the housing to perform wireless communication, the housing needs to transmit radio waves, and the housing must be formed of an insulator. However, since an insulator generally has poor heat conduction, heat dissipation through the housing is inefficient. In addition, since the sealed roof antenna is installed on the roof of the vehicle, it is exposed to sunlight in fine weather, and the housing itself is heated when the sunlight is strong. In such a case, the heat dissipation efficiency from the housing to the outside may deteriorate, or the heat of the housing may flow back to the electronic circuit.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an in-vehicle antenna device capable of radiating a circuit even under sunlight.

  In order to solve the above problems, an in-vehicle antenna device according to the present invention includes a wireless communication circuit, a casing that seals the wireless communication circuit, a heat dissipating unit provided outside the casing, and heat of the wireless communication circuit. And a heat transfer portion that transmits to the heat dissipation portion. The casing is provided with a sunshade that prevents the heat radiation part from being exposed to sunlight when the vehicle-mounted antenna device is attached to the roof of the vehicle.

  An effect of the present invention is to provide an in-vehicle antenna device capable of radiating a circuit even under sunlight.

It is a block diagram which shows the vehicle-mounted antenna apparatus of 1st Embodiment. It is a side view which shows the vehicle-mounted antenna apparatus of 2nd Embodiment. It is sectional drawing which shows the vehicle-mounted antenna apparatus of 2nd Embodiment. It is sectional drawing which shows the vehicle-mounted antenna apparatus of 3rd Embodiment. It is sectional drawing which shows the vehicle-mounted antenna apparatus of 4th Embodiment. It is sectional drawing which shows the vehicle-mounted antenna apparatus of 5th Embodiment. It is a side view which shows the vehicle-mounted antenna apparatus of 6th Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. However, the preferred embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following. In addition, the same number is attached | subjected to the same component of each drawing, and description may be abbreviate | omitted.

(First embodiment)
FIG. 1 is a block diagram illustrating an in-vehicle antenna device according to the first embodiment. The in-vehicle antenna device transmits a radio communication circuit 1, a casing 2 that seals the radio communication circuit 1, a heat radiating unit 3 provided outside the casing 2, and heat of the radio communication circuit 1 to the heat radiating unit 3. And a heat transfer section 4. Further, the housing 2 is provided with a sunshade portion 5 that prevents the heat radiating portion 3 from being exposed to sunlight when the in-vehicle antenna device is attached to the roof of the vehicle.

  With the above configuration, heat generated in the wireless communication circuit can be efficiently released to the outside even when there is solar radiation.

(Second Embodiment)
FIG. 2 is a side view showing the vehicle-mounted antenna device according to the second embodiment. An antenna line and an electronic circuit for performing wireless communication are stored in the housing 10. The housing 10 is formed of a material that does not transmit moisture or dust but transmits radio waves, for example, resin. A pad 20 for attaching to the roof of the vehicle is provided at the lower part of the housing 10. When the vehicle-mounted antenna device is attached to the roof of the vehicle, the space surrounded by the housing 10, the pad 20, and the roof is isolated from the outside in a watertight manner.

  A awning portion 11 is provided on the side surface of the housing 10 to prevent the heat radiation portion 30 disposed therebelow from being exposed to sunlight irradiated from above.

  3 is a cross-sectional view taken along the line A-A ′ of FIG. The vehicle-mounted antenna device includes a circuit board 40 on which an electronic circuit for performing wireless communication is mounted, an antenna base 50, and a bracket 51 for fixing the circuit board 40 to the antenna base 50. The antenna base 50 is a foundation of each part constituting the antenna. The lower part of the housing 10 has a shape that protrudes outward, and this part is a sunshade 11. A heat radiating part 30 is arranged below the sunshade part 11.

  The heat dissipating part 30 is a metal part having heat dissipating fins, for example, and is connected to the bracket 51 by the connecting part 31. A packing 52 is provided at a portion where the connecting portion 31 penetrates the housing 10 to prevent moisture and dust from entering from a place where the heat radiating portion 30 is installed.

  The bracket 51 is, for example, a metal plate-like component, and is fixed to the antenna base 50 with a screw 53.

  The circuit board 40 is equipped with a wireless communication circuit including a heat generating component 41 and is fixed to the bracket 51 with, for example, a screw 42. At this time, the component mounting surface of the circuit board 40 is fixed toward the bracket 51 so that the heat generating component 41 contacts the bracket 51. The antenna wire 43 used for wireless communication can be disposed along the inner wall of the housing 10, for example.

  If it is set as the above structure, the heat which generate | occur | produced in the heat-emitting component 41 is transmitted to the thermal radiation part 30 via the bracket 51 and the connection part 31. FIG. Since the heat radiating part 30 is covered by the sun shade part 11, the heat radiating part 30 is always arranged in a shaded place even in fine weather. For this reason, the temperature of the heat radiating portion 30 is relatively lower than that of the heat generating component 41, and the heat generated by the heat generating component 41 can be released from the heat radiating portion 30 to the outside. In addition, although the example which formed the sunshade part 11 integrally with the housing | casing 10 was shown in said description, the sunshade part may be produced separately from a housing | casing and may be fixed to a housing | casing.

  As described above, according to the present embodiment, the heat generated in the circuit can be efficiently released to the outside.

(Third embodiment)
FIG. 4 is a cross-sectional view showing the vehicle-mounted antenna device of this embodiment. Since most of the configuration is the same as that of the second embodiment, the same reference numerals are given to the same elements, and descriptions thereof are omitted. The in-vehicle antenna device of the present embodiment is different from the second embodiment in the thermal connection portion between the heat generating component 41 and the bracket 51.

  In the present embodiment, as in the second embodiment, the circuit board 40 is fixed to the bracket 51 with the component mounting surface facing the bracket 51. However, in this embodiment, the heat conductive sheet 44 is disposed between the heat generating component 41 and the bracket 51. The heat generated in the heat generating component 41 is transmitted to the bracket 51 via the heat conducting sheet 44 and is released to the outside from the heat radiating unit 30 as in the second embodiment. By using the heat conductive sheet 44, for example, when the upper surface of the heat generating component is not flat, the contact area with the bracket 51 can be increased. Further, when the heat generating component 41 is shorter than the other components, the space can be filled and the heat generating component 41 and the bracket 51 can be thermally connected.

  As described above, according to the present embodiment, even when direct contact between the heat-generating component 41 and the bracket 51 is difficult, the heat-generating component 41 can be efficiently radiated by thermally connecting both of them. .

(Fourth embodiment)
FIG. 5 is a cross-sectional view showing the vehicle-mounted antenna device of the present embodiment. The circuit board 40a is the same as the second and third embodiments except for the thermal connection between the circuit board 40a and the circuit board 40a and the bracket 51. For this reason, the same code | symbol is attached | subjected about the same element and the description is abbreviate | omitted.

  In the present embodiment, a method for transmitting heat of the heat generating component 41 to the bracket 51 when it is difficult to fix the circuit board 40 with the heat generating component 41 facing the bracket 51 will be described. For example, this is the case when the heat generating component 41 is lower than the other components 45.

  The circuit board 40a has a high thermal conductivity via 46 that penetrates the board. The via 46 can be formed by filling a through hole provided in the circuit board 40a with a material having a high thermal conductivity, or coating an inner wall of the through hole with a material having a high thermal conductivity. Further, a heat transfer layer 47 is provided on the surface opposite to the component mounting surface of the circuit board 40a, and the heat transfer layer 47 and the via 46 are thermally connected. The heat transfer layer 47 can be formed using, for example, a copper foil, but may be formed using other well-known techniques for forming a layer having high thermal conductivity.

  The heat generating component 41 is thermally connected to the via 46 and disposed on the surface opposite to the heat transfer layer 47. Further, the circuit board 40 a is fixed to the bracket 51 by arranging so that the contact area between the heat transfer layer 47 and the bracket 51 is increased.

  With this configuration, the heat of the heat generating component 41 is transmitted to the bracket 51 via the via 46 and the heat transfer layer 47. The heat transmitted to the bracket 51 is released to the outside from the heat radiating unit 30 as in the second and third embodiments.

As described above, according to the present embodiment, even when it is difficult to fix the circuit board with the component mounting surface facing the bracket, the heat of the heat-generating component can be reduced as in the second and third embodiments. It can be efficiently released to the outside.
(Fifth embodiment)
In this embodiment, when a plurality of circuit boards are mounted, a method for releasing the heat of the heat-generating component mounted on each circuit board to the outside will be described. As described above, the in-vehicle antenna device tends to be multifunctional, and the scale of the mounted circuit tends to increase accordingly. For this reason, a plurality of circuit boards are often mounted. This embodiment is suitable for such a case.

  FIG. 6 is a cross-sectional view showing the configuration of the circuit board and the bracket of the present embodiment. The casing and other elements are not shown.

In order to provide the two circuit boards 40b and 40c, two brackets 51b and 51c are used. In this example, the bracket 51b and the circuit board 40b have the same configuration as that of the fourth embodiment, and the bracket 51c and the circuit board 40c. Is the same as in the third embodiment. A spacer 54 is sandwiched between the two brackets 51 b and 51 c, and both brackets are fixed to the antenna base 50 with screws 53.

  With this configuration, the heat generated in the heat generating component 41c is transmitted to the bracket 51b via the heat conducting sheet 44 and the bracket 51c. Here, if a spacer 54 having a high thermal conductivity is used, the thermal conductivity efficiency from the bracket 51c to the bracket 51b can be increased.

  Further, the heat generated in the heat generating component 41 b is transmitted to the bracket 51 b through the via 46 and the heat transfer layer 47. The heat of the bracket 51b is transmitted to the heat radiating portion and released to the outside by the same action as in the second to fourth embodiments.

  Although the case where there are two circuit boards has been described here, the present invention is not limited to this, and the method of the present embodiment can be applied to cases where there are three or more circuit boards. Further, the form of transferring heat from the circuit board to the bracket is not limited to the above combination.

  As described above, according to the present embodiment, even when there are a plurality of circuit boards to be mounted, the heat of the heat-generating component mounted on each circuit board can be efficiently released to the outside.

(Sixth embodiment)
FIG. 7 is a side view showing the vehicle-mounted antenna device of the present embodiment. In the vehicle-mounted antenna device according to the present embodiment, the sunshade part 111 and the heat radiating part 130 are provided behind the housing 110. Here, the front and rear are directions in which the vehicle-mounted antenna device is installed with respect to the traveling direction of the vehicle. As is apparent from the shape of the housing 110, in order to reduce the air resistance, the narrower housing 110 is disposed toward the front of the vehicle.

  The vehicle-mounted antenna device includes a housing 110, a pad 120 for fixing the housing 110 to the roof of the vehicle, a sunshade portion 111, and a heat dissipation portion 130. The sunshade 111 is provided behind the housing 110, and the heat dissipating part 130 is disposed below the sunshade 111. Further, a packing 140 is provided at a joint portion of the heat radiating portion 130 to the housing 110 to prevent water and dust from entering the housing 110 from the joint portion.

  In this embodiment, the sunshade part 111 and the heat radiating part 130 are arranged behind the housing 110. For this reason, the sunshade part 111 and the thermal radiation part 130 do not increase air resistance at the time of driving | running | working of a vehicle. That is, the air resistance during vehicle travel can be made smaller than in the configuration in which the shade portion and the heat radiating portion are provided on the side surface of the housing as in the second embodiment.

  As described above, according to the present embodiment, the heat generated in the circuit can be efficiently released to the outside without increasing the air resistance even under sunlight.

  The present invention has been described above using the above-described embodiment as an exemplary example. However, the present invention is not limited to the above embodiment. That is, the present invention can apply various modes that can be understood by those skilled in the art within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Wireless communication circuit 2, 10, 110 Case 3, 30, 130 Heat-radiating part 4 Heat-transfer part 5, 11, 111 Awning part 20 Pad 40 Circuit board 41 Heat-generating component 42, 53 Screw 43 Antenna wire 44 Heat-conducting sheet 45 Components 46 Via 47 Heat transfer layer 50 Antenna base 51 Bracket 52, 140 Packing 54 Spacer

Claims (10)

An in-vehicle antenna device attached to a vehicle roof,
A wireless communication circuit equipped with heat-generating components;
A casing for sealing the wireless communication circuit;
A heat dissipating part provided outside the housing;
A heat transfer unit that thermally connects the wireless communication circuit and the heat dissipation unit;
A vehicle-mounted antenna device, comprising: a sunshade portion provided in the housing and preventing the heat radiating portion from being irradiated with sunlight.     When the casing has a shark fin-like shape, and the narrow side of the casing is the front and the wide side is the rear, the sunshade part and the heat dissipation part are connected to the casing. The vehicle-mounted antenna device according to claim 1, wherein the vehicle-mounted antenna device is disposed on a side of the vehicle.     When the casing has a shark fin-like shape, and the narrow side of the casing is the front and the wide side is the rear, the sunshade part and the heat dissipation part are connected to the casing. The vehicle-mounted antenna device according to claim 1, wherein the vehicle-mounted antenna device is disposed behind the vehicle.     The in-vehicle antenna device according to any one of claims 1 to 3, wherein the heat transfer unit includes a highly thermally conductive bracket for fixing the wireless communication circuit.     5. The vehicle-mounted vehicle according to claim 4, wherein the wireless communication circuit includes a circuit board on which the heat generating component is mounted, and has a second heat transfer section that thermally connects the heat generating component and the bracket. Antenna device.     The on-vehicle antenna device according to claim 5, wherein the second heat transfer unit includes a heat conductive sheet. The second heat transfer section is
A heat transfer layer formed on a surface opposite to a component mounting surface on which the heat generating component of the circuit board is mounted;
The vehicle-mounted antenna device according to claim 5, further comprising a via that thermally connects the heat generating component and the heat transfer layer. A plurality of the brackets;
The vehicle-mounted antenna device according to any one of claims 4 to 7, further comprising: the heat generating component that is thermally connected to each of the brackets. A heat dissipation method for an in-vehicle antenna device attached to a roof of a vehicle,
A wireless communication circuit with heat-generating parts is sealed in the housing,
A heat dissipating part is provided outside the housing,
Thermally connecting the wireless communication circuit and the heat dissipation unit;
A heat dissipation method for an in-vehicle antenna device, wherein the housing is provided with a sunshade that prevents the heat dissipation portion from being irradiated with sunlight.     When the casing has a shark fin shape, the narrower side of the casing is the front side and the wider side is the rear side. The heat dissipating method for an in-vehicle antenna device according to claim 9, wherein the heat dissipating method is disposed on a side or rear of the body.

Images