JP7444022B2 - Vehicle wireless communication device - Google Patents

Description

The present disclosure relates to wireless communication devices used in vehicles.

Wireless communication devices used in vehicles are required to be miniaturized due to limitations in mounting space. Patent Document 1 describes a communication device that includes an antenna for receiving a wireless signal in a predetermined frequency band, a printed circuit board (hereinafter referred to as a circuit board) on which a receiving circuit, etc. is formed, and a case that houses them. A configuration in which an antenna is integrally formed on the ceiling of the case is disclosed. In addition, in Patent Document 1, the end of the antenna provided on the ceiling and the feeding point provided on the board are brought into pressure contact using the force of screws, etc. for assembling the board to the case. Electrical connection between the circuit board and the antenna is ensured.

According to the above configuration, since it is not necessary to provide the antenna on the circuit board, it is possible to downsize the board and, by extension, downsize the device. Furthermore, since the distance between the circuit and the antenna can be increased, it is possible to reduce the influence of noise emitted from the circuit.

Japanese Patent Application Publication No. 2005-45625

A vehicle communication device has a portion that generates heat, such as a transmitting/receiving circuit. If heat builds up inside the device, electronic components may not function properly, so it is necessary to incorporate a mechanism for efficient heat dissipation. A common heat dissipation method includes, for example, a method of arranging a member having a large heat capacity, such as a metal plate, so as to be in contact with a heat source. However, in order to obtain sufficient heat dissipation, it is necessary to provide a heat dissipation member having a corresponding size, which leads to an increase in the size of the housing. On the other hand, if the heat dissipation member is made smaller with priority given to miniaturization, the desired heat dissipation performance may not be obtained.

The present disclosure has been made based on this situation, and its purpose is to provide a vehicle wireless communication device that can be miniaturized while improving heat dissipation.

A vehicle wireless communication device for achieving this purpose is a vehicle wireless communication device for implementing wireless communication using radio waves in a predetermined frequency band, and includes a circuit (61) for implementing wireless communication. The case includes a circuit board (3) on which is mounted, and a case (2) that accommodates the circuit board, and the case includes an antenna (5, 51 to 54) that can receive radio waves and a A metal heat receiving element (4) for receiving the heat is integrally formed, and the antenna is provided so as to have a portion within a predetermined nearby distance from the heat receiving element.

According to the above configuration, a part of the heat received by the heat receiving element from the circuit board is propagated to the antenna and dispersed into the resin around the antenna. In other words, the antenna also functions as a heat dissipation element. Since the antenna is formed integrally with the case and also functions as a heat dissipation element, it is possible to improve heat dissipation while reducing the size of the antenna.

Further, another vehicle wireless communication device for achieving the above object is a vehicle wireless communication device for implementing wireless communication using radio waves in a predetermined frequency band. The case includes a circuit board (3) on which a circuit (61) is mounted, and a case (2) that accommodates the circuit board, and the case includes an antenna (5, 51 to 54) that can receive radio waves, and a case that accommodates the antenna. A ground plate (8), which is a flat conductive plate that provides a ground potential of It is provided so that it has a portion that is within a predetermined neighborhood distance from.

In the above configuration, a portion of the heat received by the heat receiving element from the circuit board is propagated to the base plate and dispersed to the resin portion around the base plate. In other words, the base plate also functions as a heat dissipation element. Since the base plate is formed integrally with the case and also functions as a heat dissipation element, it is possible to reduce the size while improving heat dissipation.

Note that the numerals in parentheses described in the claims indicate correspondence with specific means described in the embodiments described later as one aspect, and limit the technical scope of the present disclosure. isn't it.

1 is an exploded perspective view for explaining the overall configuration of a vehicle wireless communication device 100. FIG. FIG. 2 is a diagram for explaining the configuration of an upper case 2. FIG. 3 is a diagram showing an example of the layout of a circuit board 3. FIG. 7 is a diagram showing a modification of the configuration of the upper case 2. FIG. 5 is a sectional view taken along line VV in FIG. 4. FIG. It is a figure which shows the structure which utilizes the base plate 8 as a heat dissipation element.

Hereinafter, embodiments of the present disclosure will be described using figures. FIG. 1 is a diagram illustrating an example of a schematic configuration of a vehicle wireless communication device 100 according to the present disclosure. The vehicle wireless communication device 100 is equipped with a plurality of antennas 5, and is capable of performing multiple functions such as cellular communication such as 4G and 5G, Bluetooth (registered trademark), Wi-Fi (registered trademark), vehicle-to-vehicle communication, and reception of GNSS signals. It is configured to be able to carry out various types of communication. Note that GNSS is an abbreviation for Global Navigation Satellite System, and refers to a satellite positioning system.

The vehicle wireless communication device 100 is installed and used at a predetermined position inside the vehicle. For example, the vehicle wireless communication device 100 is installed inside a dashboard. In addition, as another aspect, the vehicle wireless communication device 100 may be configured on the premise that it is installed on the ceiling of the vehicle interior, such as inside an overhead console, on the roof, inside a spoiler, or the like.

The vehicle wireless communication device 100 includes a lower case 1, an upper case 2, and a circuit board 3, as shown in FIG. The upper case 2 is combined with the lower case 1 to form a flat rectangular parallelepiped case (in other words, a housing) whose thickness direction is perpendicular to the circuit board 3 as a whole. In other words, the vehicle wireless communication device 100 has a flat rectangular parallelepiped external shape as a whole. The circuit board 3 is also formed in a substantially rectangular shape to correspond to the shape.

Hereinafter, the direction perpendicular to the circuit board 3 will be referred to as the vertical direction. The direction from the circuit board 3 toward the lower case 1 corresponds to the downward direction for the vehicle wireless communication device 100, and the direction from the circuit board 3 toward the upper case 2 corresponds to the upward direction.

The circuit board 3 is a substantially rectangular plate-like member formed by mounting various electronic components on a printed circuit board. As the printed circuit board, a multilayer board in which a plurality of conductor layers are built up based on an insulating layer such as a glass epoxy board can be used. The circuit board 3 is realized using, for example, a multilayer board including three or more conductor layers. The circuit board 3 includes a ground layer that is a conductor layer that is electrically connected to the ground wire of the power cable via a connector or the like. The ground layer provides a ground potential for various circuits. Note that the circuit board 3 may include a power supply layer and the like as other internal conductor layers.

In the circuit board 3, a transmitting/receiving circuit 61 including an IC for signal processing wireless signals, a power supply circuit 63, and the like are mainly formed on the lower surface of the circuit board 3 (hereinafter referred to as the lower surface 3A of the substrate). In particular, the transmitting/receiving circuit 61, which can serve as a heat source, is provided near a region of the lower surface 3A of the substrate located below the heat receiving section 41, which will be described later. Note that circuit elements such as connectors and capacitors may be arranged also on the upper surface of the circuit board 3 (hereinafter referred to as the upper surface 3B of the circuit board). The distance in the height direction between the board upper surface 3B and the upper case 2 is larger than the distance between the board lower surface 3A and the lower case 1. Therefore, the upper surface 3B of the board is suitable for arranging relatively large circuit elements such as capacitors and connectors, and the lower surface 3A of the board is suitable for arranging relatively short electronic components such as IC chips. The structure is as follows.

The configuration of the vehicle wireless communication device 100 will be described below by introducing the concept of a right-handed three-dimensional coordinate system having an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other. In various figures such as FIG. 1, the X axis represents the longitudinal direction of the circuit board 3, the Y axis represents the lateral direction of the circuit board 3, and the Z axis represents the vertical direction. In addition, as another aspect, when the circuit board 3 has a square shape, the direction along any one side can be set as the X axis. A three-dimensional coordinate system including these X-axis, Y-axis, and Z-axis is a concept for explaining the configuration of the vehicle wireless communication device 100. When the vehicle wireless communication device 100 is mounted on a vehicle, for example, the X axis corresponds to the left and right direction of the vehicle, the Y axis corresponds to the longitudinal direction of the vehicle, and the Z axis corresponds to the height direction of the vehicle. Note that when the vehicle wireless communication device 100 is mounted on a vehicle, the Z-axis positive direction corresponds to the top of the vehicle, and the Y-axis positive direction corresponds to the front of the vehicle. Therefore, in a mode in which the vehicle wireless communication device 100 is arranged in the dashboard, the negative direction of the Y-axis is the front side, in other words, the seat side when viewed from the passenger.

The lower case 1 is a member that covers the circuit board 3 from below and accommodates and supports the circuit board 3. The lower case 1 corresponds to a member that provides the bottom of the housing of the vehicle wireless communication device 100. Such a lower case 1 corresponds to a structure for protecting the lower surface 3A of the substrate. The lower case 1 is formed using a synthetic resin such as polycarbonate (PC). The lower case 1 is formed into, for example, a flat plate shape. Note that the lower case 1 may be formed into a flat (in other words, a shallow bottom) box shape with an open upper surface. Through holes 11 are formed at the four corners of the lower case 1 for screwing to the upper case 2 with the circuit board 3 interposed therebetween. Note that the position of the through hole 11 can also be changed as appropriate. The through holes 11 may be provided at four or more locations. Further, as a method for maintaining the combined state of the lower case 1, upper case 2, and circuit board 3, various locking structures such as snap-fitting, in addition to screwing, can be employed.

As the material for the lower case 1, various resins such as polycarbonate can be used. The material of the lower case 1 may be made of a resin material that can maintain desired strength in the temperature range assumed as the environment in which the vehicle wireless communication device 100 is used (hereinafter referred to as the operating temperature range). good. The operating temperature range can be, for example, -20°C to 100°C.

The upper case 2 is a member that covers the circuit board 3 from above and accommodates and supports the circuit board 3. The upper case 2 is configured to fit with the lower case 1 while accommodating the circuit board 3. The upper case 2 is formed into a substantially box shape with an open lower surface. Specifically, it includes a ceiling part 21 that faces the upper side surface 3B of the substrate at a predetermined distance, and a side wall part 22 that extends downward from the edge of the ceiling part 21. The ceiling portion 21 corresponds to a structure that provides an upper surface portion of the housing of the vehicle wireless communication device 100. The side wall portion 22 is formed in such a size and shape that its edge portion (in other words, an edge portion) is combined with the edge portion of the lower case 1 .

Hereinafter, among the four side wall parts 22 of the upper case 2, the side wall part 22 located on the Y-axis positive direction side will be referred to as a first side wall part 22A, and the side wall part 22 located on the X-axis negative direction side will be referred to as a second side wall part 22A. It is called a side wall portion 22B. Further, the side wall portion 22 located on the negative side of the Y-axis is referred to as a third side wall portion 22C, and the side wall portion 22 located on the positive side of the X-axis is referred to as a fourth side wall portion 22D. An opening 221 for passing cables and the like is formed in the third side wall 22C.

Further, as shown in FIG. 2, a heat receiving element 4, which is a metal body, is arranged on the first side wall portion 22A of the upper case 2 to release heat from the circuit board 3 to the case. Note that FIG. 2 is a perspective view of the upper case 2 through which the resin portion is transparent. The heat receiving element 4 is formed by, for example, bending a rectangular sheet metal into an L shape. The heat receiving element 4 can be handled by being divided into a heat receiving section 41 and a heat transfer section 42 with the bent portion as a boundary. The heat receiving portion 41 is a portion that comes into contact with the upper side surface 3B of the substrate. The heat transfer section 42 is configured to play the role of conducting the heat received from the circuit board 3 by the heat receiving section 41 to the upper case 2. Furthermore, the heat transfer section 42 also plays a role of fixing the heat receiving section 41 to the upper case 2. The heat transfer section 42 corresponds to a support section. The heat receiving element 4 is insert-molded with the upper case 2 so that the heat transfer part 42 is covered with the resin forming the first side wall part 22A. Insert molding here refers to a molding method in which resin is injected around a metal part inserted into a mold to integrate metal and resin. Of the L-shaped metal plate formed by bending a single sheet metal, a portion that is assembled/embedded in the side wall portion 22 corresponds to the heat transfer portion 42. Further, a portion that is in contact with the circuit board 3 directly or indirectly via a shield plate 7 to be described later corresponds to the heat receiving portion 41 . As an example, both the heat receiving section 41 and the heat transfer section 42 are formed into a generally rectangular shape.

The heat receiving section 41 corresponds to a metal plate that extends from the lower end of the heat transfer section 42 toward the inside of the case. It can also be said that such a heat receiving section 41 is arranged to stand approximately perpendicularly to the heat transfer section 42 at the lower edge of the heat transfer section 42 . The lateral position of the heat receiving element 4 is designed such that the heat receiving part 41 is located on the back side of the heat generating part (heat source) of the circuit board 3. Further, the height position of the heat receiving element 4 is set such that the heat receiving portion 41 is in contact with the circuit board 3. The lower surface of the heat receiving section 41 is formed flat so that it can be bonded to the upper surface 3B of the substrate using a thermally conductive adhesive. Note that a shield member such as a metal plate or film that shields electromagnetic waves emitted by the antenna 5 may be interposed between the heat receiving portion 41 and the upper substrate surface 3B. The size and shape of the heat receiving section 41 can be changed as appropriate. The larger the heat receiving part 41 is, the more improved heat dissipation performance can be expected.

The heat transfer section 42 is configured to propagate the heat received from the circuit board 3 by the heat receiving section 41 to the upper case 2. In one aspect, the heat transfer section 42 corresponds to a configuration in which the heat transfer section 42 is arranged substantially perpendicularly to the heat reception section 41 at the edge of the heat reception section 41 where the side wall section 22 is present. Note that the heat transfer portion 42 does not necessarily need to be buried in the first side wall portion 22A, and may be attached to the inner surface of the first side wall portion 22A. The heat transfer portion 42 may be assembled to the first side wall portion 22A so as to have a portion buried in the first side wall portion 22A and a portion exposed. The size and shape of the heat transfer section 42 can be changed as appropriate. The larger the heat transfer portion 42 is, the more improved heat dissipation performance can be expected. If the height of the side wall portion 22 is H, then the length of the heat transfer portion 42 in the vertical direction is set to, for example, H/2 or more.

Note that it is sufficient that the heat receiving section 41 and the heat transfer section 42 are thermally and physically connected, and may be realized by combining separate members. Further, it is sufficient that the heat receiving portion 41 is configured to propagate heat to the side wall portion 22, and the shape of the heat transfer portion 42 does not need to be flat. In addition, the heat receiving section 41 may be supported, for example, by a recess 211 provided in the ceiling section 21 at a position where it comes into contact with the upper surface 3B of the substrate. In addition, a plurality of protrusions (so-called fins) functioning as a heat sink may be formed on the upper side of the heat receiving section 41. Each protrusion may be plate-shaped or rod-shaped. The plurality of protrusions provided on the upper surface of the heat receiving section 41 may be exposed to the outside of the case through holes provided at the bottom of the recess 211.

Further, as shown in FIG. 2, a plurality of antennas 5 are insert-molded in the upper case 2. Here, as an example, four antennas 5, antennas 51 to 54, are provided on the side wall of the upper case 2. Each antenna 5 is provided integrally with the upper case 2 in such a manner that a portion thereof is buried in the resin and a portion thereof is exposed inside the case. Hereinafter, the wavelength of radio waves transmitted and received by each antenna 5 will also be referred to as λ. Since the radio waves targeted for transmission and reception may differ for each antenna 5, λ may also differ for each antenna 5. Further, the wavelength λ hereinafter refers to a value (so-called effective length) that takes into consideration the wavelength shortening effect due to the dielectric material.

The antenna 51 is an antenna for transmitting and receiving radio waves (in other words, wireless signals) in a frequency band used in, for example, cellular communication. In other words, the antenna 51 is an antenna for performing data communication with a wireless base station that constitutes a 4G or 5G mobile communication system. For example, the antenna 51 is configured to be able to transmit and receive radio waves in the 2.5 GHz band. The above operating frequency of the antenna 51 is an example, and is not limited to the 2.5 GHz band. The operating frequency bands are 700MHz band, 800MHz band, 900MHz band, 1.5GHz band, 1.7GHz band, 2GHz band, 2.5GHz band, 3.4GHz band, 3.7GHz band, 4.5GHz band, and 28GHz band. etc.

Note that the antenna 51 may be a transmitting/receiving antenna, or may be a receiving only antenna. In the present disclosure, the expression "antenna for transmitting and receiving wireless signals in a certain frequency band" can include not only antennas used for both transmission and reception, but also antennas used only for reception. In other words, the expression "transmission and reception" can be interpreted as at least one of transmission and reception and reception. The same applies to the description of transmitting/receiving circuits, etc. Further, since the operation of an antenna is reversible in transmitting and receiving radio waves, an antenna capable of receiving a certain radio wave can be understood as an antenna capable of transmitting the radio wave.

The antenna 51 is provided integrally with the first side wall portion 22A. The antenna 51 is disposed, for example, on the first side wall portion 22A, on the negative side of the X-axis relative to the heat transfer portion 42. Further, a portion of the antenna 51 extends to a region above the heat transfer section 42 .

The antenna 51 is configured, for example, as an inverted F antenna. Specifically, it includes a main body 51A, a short-circuiting extension 51B, and a power feeding extension 51C. Most or the entire area of the main body portion 51A is covered with resin forming the first side wall portion 22A. A portion of the main body portion 51A is close to the heat transfer portion 42. For example, the main body portion 51A has a portion that is separated from the heat transfer portion 42 by less than a predetermined nearby distance. The neighborhood distance here is a value that can be considered as being close to the heat transfer section 42, and can be, for example, about 5 mm to 15 mm. The neighborhood distance can be interpreted as a limit value of the distance at which heat can be propagated from the heat transfer part 42 to the antenna 5 preferentially compared to the resin part of the upper case 2. According to the configuration in which the antenna 51 is disposed close to the heat transfer section 42 in this manner, the antenna 51 can easily receive heat from the heat transfer section 42 . Note that the distance between the main body portion 51A and the heat transfer portion 42 is 1 mm or more even at the closest point. This is because if the main body part 51A and the heat transfer part 42 are too close, there is a possibility that these members will be capacitively coupled in terms of high frequency, and the operating frequency will shift.

The shorting extension part 51B and the power feeding extension part 51C are arranged at a position where the antenna 51 operates as an inverted F antenna. The shorting extension part 51B and the power feeding extension part 51C can be adjusted as appropriate in consideration of impedance matching and the like. In addition, the short-circuiting extension part 51B and the power feeding extension part 51C can be formed by bending a strip/linear conductor that extends continuously from the main body part 51A. That is, the main body portion 51A, the short-circuiting extension portion 51B, and the power feeding extension portion 51C can be produced by bending a member cut out from a single metal plate. One end of the short-circuiting extension 51B is connected to the main body 51A, and the other end is electrically connected to the ground layer provided on the circuit board 3. One end of the power feeding extension 51C is connected to the main body 51A, and the other end is electrically connected to a power feeding line provided on the circuit board 3. Note that the length of each part of the antenna 51 is set so that the path length of the resonant current is an integral multiple of λ/4.

Note that the electrical connection between the tip portions of the short-circuiting extension portion 51B and the power feeding extension portion 51C and the circuit board 3 may be realized using a clip structure or a connector having an insertion hole. As the clip structure, it is possible to adopt a structure in which metal terminals sandwich the tip of the short-circuiting extension part 51B from the left and right sides. The metal terminal constituting the clip structure may be configured as a plate spring that expands outward (in other words, bends) due to the pressing force when the short-circuiting extension portion 51B is inserted, for example. Note that the clip terminal only needs to be configured to press the short-circuiting extension part 51B from the left and right by its elasticity (in other words, restoring force), and various structures can be adopted as the specific structure. . Although the connection structure between the short-circuit extension part 51B and the circuit board 3 has been described above, the connection method between the power supply extension part 51C and the circuit board 3 can be made in the same way. Further, the same can be applied to the short-circuit extension part and the power feeding extension part provided in other antennas 5 to be described later. The short-circuiting extension part 51B and the power feeding extension part 51C are configured to connect the antenna and the circuit, and therefore can be called a circuit connection part.

Note that the antenna 51 may be a monopole antenna. Furthermore, the antenna 51 may be configured as a multiband antenna that operates at multiple frequencies. Note that a multiband antenna can be realized by providing a branching element in the feeding element so that the path length from the feeding point corresponds to the target frequency, or by arranging a parasitic element close to the feeding element. . Various configurations can be adopted as the structure of the multiband antenna. In addition, the antenna 51 may be configured as a plate-shaped antenna such as a plate-shaped inverted F antenna.

The antenna 52 can be, for example, an antenna for transmitting and receiving radio waves in a frequency band different from that of the antenna 51 among radio waves in a frequency band used in cellular communication. For example, the antenna 52 may be configured as a double-band antenna capable of transmitting and receiving radio waves in the 700 MHz band and radio waves in the 1.5 GHz band. Of course, the antenna 52 may be configured to operate at the same frequency as the antenna 51 in order to achieve reception diversity and the like.

The antenna 52 is also the antenna 5 that is provided integrally with the first side wall portion 22A. For example, the antenna 52 is disposed closer to the X-axis positive direction than the heat transfer section 42 in the first side wall section 22A. Note that a portion of the antenna 52 may extend to a region above the heat transfer section 42.

The antenna 52 is configured as a monopole antenna, for example. That is, the antenna 52 is configured as a linear antenna having a length that is an integral multiple of λ/4. The feeding point is provided, for example, in a conductor portion extending from the lower end of the side wall portion 22, as shown in the figure. Of course, the power feeding point can be formed at any position using the same three-dimensional structure as the power feeding extension 51C. For example, most of the antenna 52 is covered with resin that forms the first side wall portion 22A.

Preferably, the antenna 52 also has a portion that is close to the heat transfer portion 42, similarly to the antenna 51. For example, the antenna 52 has a portion extending parallel to the edge of the heat transfer portion 42 on the positive side of the X-axis with a distance of, for example, about 3 mm to 15 mm. According to the configuration in which the antenna 52 is disposed close to the heat transfer section 42 in this manner, the antenna 52 can easily receive heat from the heat transfer section 42 . Note that the antenna 52 and the heat transfer section 42 are configured to be separated from each other by 1 mm or more.

The antenna 53 is an antenna for receiving signals from navigation satellites that constitute GNSS, for example. Such an antenna 53 can also be called a satellite communication antenna. As the GNSS, satellite positioning systems such as GPS, GLONASS, Galileo, IRNSS, QZSS, and Beidou can be adopted. The antenna 53 is provided, for example, integrally with the second side wall portion 22B. Antenna 53 is also configured to operate as an inverted F antenna like antenna 51. Specifically, it includes a main body 53A, a short-circuiting extension 53B, and a power feeding extension 53C. Most or the entire area of the main body portion 53A is covered with resin forming the second side wall portion 22B. The configurations of the short-circuit extension part 53B and the power supply extension part 53C can be the same as those of the short-circuit extension part 51B and the power supply extension part 51C. The length of each part of the antenna 53 is set so that the path length of the resonant current is an integral multiple of λ/4.

The antenna 54 is an antenna for transmitting and receiving wireless signals compliant with a predetermined short-range wireless communication standard such as Bluetooth (registered trademark) or Wi-Fi (registered trademark). That is, the antenna 54 is configured to be able to transmit and receive at least one of a 2.4 GHz band radio wave and a 5 GHz band radio wave. The antenna 54 is, for example, provided integrally with the fourth side wall portion 22D. The antenna 54 may be configured as a plate antenna such as a patch antenna, or may be configured as a linear antenna such as a monopole antenna or an inverted F antenna. For example, the antenna 54 is configured as a plate-shaped inverted F antenna. That is, the antenna 54 includes a flat main body 54A, a short-circuiting extension 54B, and a power feeding extension 54C.

The main body portion 54A is a conductive plate whose circumference is set to an even multiple of λ/4. The short-circuiting extension portion 54B is a conductive member extending toward the inside of the case from the lower end of the main body portion 54A, and is electrically connected to the ground layer of the circuit board 3. The power feeding extension part 54C is an L-shaped conductor member extending from the edge of the main body part 54A on the Y-axis negative direction side, and the end thereof is connected to the power feeding line of the circuit board 3. .

Note that the roles and configurations of the antennas 51 to 54 described above are merely examples, and the present invention is not limited thereto. As the configuration of the antenna 5, a loop antenna or the like can also be adopted. Moreover, the antenna 5 may be configured as a patch antenna. When configured as a patch antenna, the antenna 5 includes a patch portion, which is a metal plate having a width of λ/2, and a ground plate placed opposite the patch portion. The patch portion may be insert-molded, for example, so as to be buried inside the side wall portion 22. Further, the conductor plate serving as the ground plate may be attached to the inner surface of the side wall portion 22 so as to face the patch portion. A power feeding point may be formed at any position on the center line in the width direction of the patch portion using a configuration similar to that of the power feeding extension portion described above. The ground plane is connected to circuit ground. The base plate may also be integrated with the second side wall portion 22B by insert molding or the like. In addition, as the antenna 5, a zero-order resonant antenna or the like can be adopted.

Further, in addition to the antennas described above, an antenna for V2X communication performed using radio waves in the 5.9 GHz band or 700 MHz band may be provided. Note that the first letter "V" in V2X refers to the vehicle as the own vehicle, and "X" can refer to various entities other than the own vehicle, such as pedestrians, other vehicles, road equipment, networks, servers, etc. . "X" can be interpreted as Everything/Something. The number of antennas 5 included in vehicle wireless communication device 100 can be changed as appropriate.

In addition, the inner surface of the upper case 2 is integrally provided with a plurality of stepped portions for supporting the circuit board 3, short-circuiting extensions 51B, 53B, 54B, power feeding extensions 51C, 53C, 54C, etc. (all not shown). The stepped portion may also serve to hold down the circuit board 3 from above. The step portion is formed downward from the ceiling portion 21 along the side wall portion 22. The step portion extends downward from the inner surface of the ceiling portion 21 to a predetermined height position. The step portion regulates the relative position (separation and posture) of the circuit board 3 with respect to the upper case 2. The lower ends of some of the stepped portions are configured to abut against the upper side surface 3B of the substrate.

<About the layout of circuit board 3>
As shown in FIG. 3, a transmitting/receiving circuit 61, an interface circuit 62, a power supply circuit 63, and the like are formed on the lower surface 3A of the substrate. The transmitting/receiving circuit 61 is a circuit module that performs predetermined signal processing on the signal received by the antenna 5 and generates a signal to be transmitted from the antenna 5. The transmitting/receiving circuit 61 is at least one of a circuit for extracting received data by performing predetermined signal processing on the signal received by the antenna 5, and a circuit for outputting a transmission signal to the antenna 5 and transmitting it as a radio wave. Including one. That is, the transmitting/receiving circuit 61 includes at least one of a modulation circuit, a demodulation circuit, a detection circuit, a signal amplifier, a frequency converter, a phase adjuster, and the like. As an example, the circuit board 3 of this embodiment includes four transmitting/receiving circuits 61A to 61D corresponding to each of the antennas 51 to 54.

The transmitting/receiving circuit 61A is a transmitting/receiving circuit 61 electrically connected to the antenna 51, and the transmitting/receiving circuit 61B is a transmitting/receiving circuit 61 electrically connected to the antenna 52. The transmitting/receiving circuit 61C is a transmitting/receiving circuit 61 electrically connected to the antenna 53, and the transmitting/receiving circuit 61D is a transmitting/receiving circuit 61 electrically connected to the antenna 54. A feed line for feeding power to the corresponding antenna 5 is connected to each transmitter/receiver circuit 61 . The feed line may be patterned, for example, on the surface of the substrate, or may be formed using an internal conductor layer. Note that a plurality of antennas 5 may be connected to one transmitting/receiving circuit 61. The transmitting/receiving circuits 61 for a plurality of antennas 5 having a common purpose may be integrated. For example, the antenna 51 and the antenna 52 may be connected to the same transmitting/receiving circuit 61.

The transmitting/receiving circuits 61A to 61D are arranged together. The area where the transmitting/receiving circuit 61 is arranged corresponds to the core area of the circuit board 3. The transmitting/receiving circuits 61A to 61D are arranged on the heat absorbing region Rd, which is a region located on the back side of the heat receiving section 41, and in the vicinity of the heat absorbing region Rd. Note that in FIG. 3, a portion corresponding to the heat absorption region Rd is hatched in a diagonal line pattern. The back surface portion of the area where the transmitting/receiving circuit 61 is arranged corresponds to a predetermined area to which the heat receiving section 41 is to be directly or indirectly (that is, thermally) connected.

Interface circuit 62 is a circuit module for communicating with other devices connected to the vehicle. For example, the interface circuit 62 includes a circuit for converting signal formats, a buffer circuit for temporarily storing received data, a buffer circuit for temporarily storing transmitted data, and the like. The interface circuit 62 can include a configuration (so-called I/O device) that converts a logical signal into an actual electrical signal in Ethernet (registered trademark), UART, or the like. Note that I/O devices compatible with various communication standards are often realized as chipsets (so-called PHY chips). The interface circuit 62 may include a PHY chip that conforms to a predetermined communication standard.

Interface circuit 62 includes a communication connector (not shown). The communication connector is a component to which a predetermined communication cable is connected. The communication connector is arranged along the edge of the upper side surface 3B of the board where the opening 221 is provided, that is, the edge on the Y-axis negative direction side. Various cables extending from the communication connector are drawn out to the outside of the case, for example, through an opening 221 provided in the third side wall 22C.

Such an interface circuit 62 is arranged in a region located on the back side of the communication connector on the lower side surface 3A of the board. In other words, the interface circuit 62 is arranged in a range on the negative side of the Y-axis with respect to the core region where the transmitting/receiving circuits 61A to 61D are arranged.

The power supply circuit 63 is a circuit module that converts the voltage supplied from the vehicle power supply into an operating voltage for each circuit and outputs the voltage. A power supply circuit 63 is also arranged near the opening 221. For example, the power supply circuit 63 is formed from the opening 221 side toward the positive Y-axis direction so as to be adjacent to the interface circuit 62 in the X-axis direction. Such an arrangement also corresponds to an arrangement in which the power supply circuit 63 is arranged at a position farther from the heat absorption region Rd than the transmitting/receiving circuit 61. Note that the power supply circuit 63 may include a power connector connected to a power cable. Like the communication connector, the power supply connector is also arranged at a position within a predetermined distance from the opening 221 on the upper side surface 3B of the board. Note that the power connector may be integrated with the communication connector.

In addition, an electrode (for example, a land) for electrical connection with the short-circuiting extension 51B of the antenna 5 is formed on the lower surface 3A of the substrate or the upper surface 3B of the substrate. A clip structure or the like for electrical connection with the short-circuiting extension part 51B or the like is arranged on the land serving as the electrode. With this configuration, each antenna 5 is electrically connected to the corresponding transmitting/receiving circuit 61. Note that when the connection point with the antenna 5 is provided on the lower side surface 3A of the circuit board 3, a through hole is provided in the circuit board 3 through which the shorting/power feeding extension of the antenna 5 passes to the lower side of the circuit board 3. shall be taken as a thing. A configuration, such as a through hole or a clip structure, provided on the circuit board 3 for electrically connecting to the antenna 5 will also be referred to as an antenna connection portion.

<Method for manufacturing communication device>
Next, an example of a method for manufacturing the vehicle wireless communication device 100 described above will be briefly described. It is assumed that the heat receiving element 4, the antenna 5, etc. are previously integrally assembled into the upper case 2 by insert molding. It is also assumed that a circuit board 3, which is a printed circuit board on which various electronic components are mounted, is also prepared separately.

For example, the following procedure can be adopted as the assembling process of the vehicle wireless communication device 100. That is, first, a thermally conductive adhesive is applied to the lower surface of the heat receiving portion 41 of the heat receiving element 4. Then, the circuit board 3 is assembled to the upper case 2 so that the circuit connection part of each antenna 5 is connected to the antenna connection part provided on the circuit board 3, and the heat receiving part 41 is in contact with the top surface 3B of the board. . For positioning during assembly, steps, guides (grooves), etc. provided in the upper case 2 can be used. Then, the lower case 1 is assembled into the opening of the upper case 2 with the circuit board 3 assembled, and these are fastened together using screws or the like. Through the above work steps, the vehicle wireless communication device 100 can be manufactured.

<About the effects of this embodiment>
In the above configuration, among the various circuit modules included in the circuit board 3, the transmitting/receiving circuit 6, which relatively easily generates heat, is arranged closer to the heat absorption region Rd with priority than other circuit modules. According to this configuration, the heat generated in each transmitting/receiving circuit 61 is easily absorbed by the heat receiving section 41. Note that the vicinity of the endothermic region Rd here refers to a range within, for example, 3 to 4 cm from the endothermic region Rd. Further, circuit modules other than the transmitting/receiving circuit 61 refer to the interface circuit 62, the power supply circuit 63, and the like.

Further, the heat received by the heat receiving section 41 from the circuit board 3 is propagated to the heat transfer section 42 , and from the heat transfer section 42 to the side wall section 22 . A part of the heat propagated to the side wall part 22 is radiated to the outside from the side wall part 22, and also propagated to the ceiling part 21, so that the heat can be radiated from the ceiling part 21 as well. That is, heat is dispersed and radiated from the side wall portion 22 and the ceiling portion 21 where the heat transfer portion 42 is provided.

In addition, according to the configuration of the present disclosure, the antenna 5 is integrally formed on the side wall portion 22 where the heat transfer portion 42 is provided. The conductor that constitutes the antenna 5 has higher thermal conductivity than resin. According to the configuration in which the antenna 5 is arranged close to the heat receiving element 4, the heat received by the heat receiving section 41 from the circuit board 3 is easily propagated to the antenna 5. As a result, the antenna 5 itself can function as a heat dissipation element. Further, since the antenna 5 is formed to have a length of λ/4 or more inside or on the surface of the side wall portion 22 and to extend in, for example, the X-axis direction and the Z-axis direction, heat is likely to be widely dispersed. That is, according to the above configuration, heat is difficult to concentrate near the heat receiving section 41 and the heat transfer section 42. Since the antenna 5 thus acts as a heat propagation medium, heat is easily radiated from the entire upper case 2. As a result, the temperature rise inside the case, specifically the circuit board 3, can be suppressed. In particular, according to the configuration in which the antennas 51 and 52 are arranged on both the left and right sides of the heat receiving element 4 as in the above configuration, an effect of further dispersing the heat from the heat receiving section 41 can be expected. In addition, according to the configuration in which a part of the antenna 5 near the heat receiving element 4 is buried in the side wall part 22, the antenna 5 and the side wall part 22 are The contact area becomes larger. Therefore, the propagation of heat to the antenna 5 can be improved.

Additionally, in the above configuration, the antenna 5 is provided on the side wall portion 22 of the upper case 2. According to this configuration, the shape of the antenna 5 can be changed depending on the side surface shape of the upper case 2. That is, by increasing the degree of freedom in antenna shape, it becomes easier to secure an antenna shape that corresponds to the required antenna directivity. Furthermore, since the antenna 5 can be easily formed three-dimensionally, the degree of difficulty in designing for ensuring a desired antenna gain can be alleviated. In other words, the degree of freedom in designing the directivity of the antenna 5 can be increased.

In addition, in the present embodiment, the antenna 5 is integrally formed with the upper case 2, and the circuit board 3 is assembled to the upper case 2, so that the electrical connection between the circuit board 3 and the antenna 5 is ensured. Ru. According to this configuration, it is not necessary to solder the antenna 5 to the circuit board 3 in order to ensure the electrical connection between the antenna 5 and the circuit board 3. Therefore, the soldering process between the antenna 5 and the circuit board 3 can be eliminated as a manufacturing process for the vehicle wireless communication device 100. In other words, the manufacturing process of the vehicle wireless communication device 100 can be simplified.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications described below are also included within the technical scope of the present disclosure. Various modifications and changes can be made without departing from the scope of the invention. For example, the various modifications described below can be implemented in appropriate combinations within a range that does not cause technical contradiction. It should be noted that members having the same functions as those described in the above-described embodiments are given the same reference numerals, and their explanations will be omitted. Furthermore, when only a part of the configuration is mentioned, the configuration of the previously described embodiment can be applied to other parts.

<Supplementary information on the configuration of upper case 2>
As shown in FIGS. 4 and 5, a shield plate 7, which is a plate-like member having radio wave blocking properties, may be attached to the upper case 2 at a position in contact with the upper side surface 3B of the board. The shield plate 7 is attached so as to face the inner surface of the ceiling part 21. The shield plate 7 may be held by a shield frame that is a framework that is integrally assembled with the side wall portion 22.

The shield plate 7 is configured to suppress electromagnetic waves emitted from the antenna 5 from propagating as noise to the transmitting/receiving circuit 61, or preventing electromagnetic waves emitted from the transmitting/receiving circuit 61 from reaching the antenna 5 as noise. In other words, this is a configuration for electromagnetically separating a space where the antenna 5 exists and a space where the circuit board 3 exists. Note that the shield plate 7 is set to a size that covers only noise sources or areas susceptible to the influence of noise, such as the transmitting/receiving circuit 61. Of course, the shield plate 7 may be configured to cover the entire area of the upper side surface 3B of the substrate. The shield plate 7 is realized using a metal plate such as aluminum, copper, or iron. The shield plate 7 may be a resin plate whose radio wave blocking properties are enhanced by containing metal powder or the like, or may be a resin plate to which a radio wave blocking film is attached. However, from the viewpoint of heat conductivity from the circuit board 3 to the heat receiving section 41, the shield plate 7 is preferably made of metal such as aluminum.

The height position of the shield plate 7 within the case is set so that it also comes into contact with the lower surface of the heat receiving section 41 . Such a configuration corresponds to a configuration in which a shield plate 7, which is a plate-like member having radio wave blocking properties, is interposed between the heat receiving portion 41 and the upper substrate surface 3B. In this configuration, heat generated by the transmitting/receiving circuit 61 and the like is transmitted to the heat receiving section 41 via the shield plate 7. Then, the heat transfer section 42 transfers the heat from the heat receiving section 41 to the upper case 2 and the antenna 5, and disperses the heat. The shield plate 7 corresponds to another metal member.

According to this configuration, in addition to the effects of the embodiments described above, there is an advantage that the operational stability of the electronic components on the circuit board 3 and the antenna 5 is improved. In addition, as another aspect, the shield plate 7 may be provided above the heat receiving part 41. The shield plate 7 only needs to be provided between the main body of the antenna 5 and the circuit board 3. Further, in order to reduce the weight, the shield plate 7 may be provided with a plurality of holes whose diameter is sufficiently small (for example, one-tenth or less) of the wavelength of radio waves handled by the vehicle wireless communication device.

<Supplementary information on the configuration of antenna 5>
Although the embodiment in which the plurality of antennas 5 are all integrally provided with the upper case 2 by insert molding has been disclosed above, the present invention is not limited to this. Some or all of the plurality of antennas 5 may be patterned on the inner surface of the upper case 2. The pattern shape of the antenna 5 can be changed as appropriate. The pattern shape of the antenna 5 also includes the length and width of the linear conductor. Examples of methods for patterning the antenna 5 include electroplating, metal vapor deposition, and application of conductive paint. In addition to the antenna 5, a conductor foil, a metal plate, or a metal wire processed into a desired pattern may be adhered to the upper case 2. A metal plate or metal wire formed into a desired shape may be fixed to the upper case 2 by hot caulking.

Further, in the above description, a mode in which a linear antenna such as an inverted F antenna or a monopole is provided on the heat-receiving side wall portion 22α, which is the side wall portion 22 where the heat-receiving element 4 is provided, is illustrated, but the present invention is not limited to this. For example, a plate-shaped antenna such as a plate-shaped inverted F antenna may be provided on the heat receiving side wall portion 22α. A plate antenna has a larger volume and surface area of a metal part than a linear antenna. Therefore, according to a configuration in which a plate antenna is provided on the heat receiving side wall portion 22α, heat dissipation performance can be improved compared to a configuration in which a linear antenna is provided. Note that the heat receiving side wall portion 22α herein refers to the side wall portion 22 that plays a role of receiving heat from the heat receiving portion 41, and is the side wall portion 22 adjacent to the heat receiving portion 41, or the side wall closest to the heat receiving portion 41. It can also be understood as part 22.

Further, when a plurality of antennas 5 are provided as in the above-described embodiment, it is preferable that the antenna 5 disposed close to the heat receiving element 4 has the largest area among the plurality of antennas 5. According to such a configuration, it becomes possible to most efficiently disperse the heat received by the heat receiving element 4 from the circuit board 3. In addition, although the structure provided with the several antenna 5 was disclosed above, it is not limited to this. The vehicle wireless communication device 100 may include only one antenna 5.

Although the configuration in which only one heat receiving element 4 is provided has been disclosed above, the present invention is not limited to this. A plurality of heat receiving elements 4 may be provided. For example, the heat receiving element 4 may be provided on each of the first side wall portion 22A and the second side wall portion 22B, which are relatively close to the transmitting/receiving circuit 61. Accordingly, there may be a plurality of heat receiving side wall portions 22α. The antenna 5, which also serves as a heat dissipation element, may be provided on at least one of the plurality of heat receiving side walls 22α.

Although the embodiment in which the plurality of antennas 5 are provided on the side wall portion 22 has been disclosed above, the present invention is not limited to this. One or more antennas 5 may be provided on the ceiling portion 21. For example, an inverted F antenna, a monopole antenna, or the like may be formed on the ceiling portion 21 as the antenna 5.

Although the embodiment in which the antenna 5 itself doubles as a heat dissipation element has been disclosed above, the present invention is not limited to this. For example, as shown in FIG. 6, a ground plate 8, which is a conductive plate that provides a ground potential for the antenna 51, may be provided near the heat receiving element 4, and the ground plate 8 may be used as a heat radiating element. That is, at least one antenna 5 or the ground plate 8 of the antenna 5 may be provided on the heat receiving side wall portion 22α. The ground plane 8 here refers to a member that is electrically connected to the ground layer of the circuit board 3 and has a size that provides a mirror image effect. In the example shown in FIG. 6, the antenna 51 is configured to operate as a monopole antenna. The length of the base plate 8 in the X-axis direction is set to λ/4 or more, more preferably 0.75λ or more.

Note that the ground plate 8 may be connected to the heat receiving element 4. Furthermore, the heat receiving element 4 may be used as the ground plane 8 by connecting it to the ground layer of the circuit board 3. In addition, the antenna 5 may be configured to transmit and receive radio waves of a desired frequency using a parasitic element. The concept of the antenna 5 is not limited to a conductive element provided with a feeding point, but also includes a structure that is excited by being coupled to a conductor provided with a feeding point at a high frequency (that is, a parasitic element). A feeding element, a parasitic element, or a ground plate 8 functioning as at least one antenna may be provided on the side wall portion 22 where the heat receiving element 4 is provided.

100 vehicle wireless communication device, 1 lower case, 2 upper case (case), 21 ceiling section, 22A to 22D side wall section, 22α heat receiving side wall section, 3 circuit board, 4 heat receiving element, 41 heat receiving section, 42 heat transfer section (support) 5.51-54 Antenna, 61 Transmission/reception circuit (heat source), 62 Interface circuit, 63 Power supply circuit, Rd Heat absorption area

Claims (9)

A vehicle wireless communication device for performing wireless communication using radio waves in a predetermined frequency band,
a circuit board (3) on which a circuit (61) for implementing the wireless communication is mounted;
A case (2) that accommodates the circuit board,
An antenna (5, 51 to 54) capable of receiving the radio waves and a metal heat receiving element (4) for receiving heat generated in the circuit board are integrally formed in the case,
In the vehicle wireless communication device, the antenna is provided so as to have a portion within a predetermined proximity distance from the heat receiving element. The vehicle wireless communication device according to claim 1,
The case includes a ceiling part (21) that covers above the circuit board, and a plurality of side walls (22) that surround the circuit board,
The heat receiving element is provided on at least one of the plurality of side walls,
A wireless communication device for a vehicle, wherein the antenna is provided on a heat-receiving side wall portion (22α) that is the side wall portion where the heat-receiving element is provided. The vehicle wireless communication device according to claim 2,
The heat receiving element includes a flat heat receiving portion (41) that is in contact with a predetermined area of the circuit board, either directly or indirectly through another metal member;
A wireless communication device for a vehicle, comprising: a support section (42) configured to support the heat receiving section and provided integrally with the heat receiving side wall section. The vehicle wireless communication device according to claim 3,
The heat receiving element is a vehicle wireless communication device in which the support portion is integrated with the heat receiving side wall portion by insert molding. The vehicle wireless communication device according to any one of claims 2 to 4,
A vehicle wireless communication device in which at least a portion of the antenna is buried inside the heat receiving side wall. The vehicle wireless communication device according to any one of claims 2 to 5,
comprising a plurality of the antennas,
A wireless communication device for a vehicle, wherein the largest antenna among the plurality of antennas is arranged such that it has a portion within the vicinity distance from the heat receiving element in the heat receiving side wall portion. The vehicle wireless communication device according to any one of claims 1 to 6,
In the vehicle wireless communication device, the antenna having a portion within the vicinity distance from the heat receiving element is a plate antenna. The vehicle wireless communication device according to any one of claims 1 to 6,
In the vehicle wireless communication device, the antenna having a portion within the vicinity distance from the heat receiving element is a linear antenna. A vehicle wireless communication device for performing wireless communication using radio waves in a predetermined frequency band,
a circuit board (3) on which a circuit (61) for implementing the wireless communication is mounted;
A case (2) that accommodates the circuit board,
In the above case,
an antenna (5, 51 to 54) capable of receiving the radio waves;
a ground plate (8) that is a flat conductor plate that provides a ground potential for the antenna;
A metal heat receiving element (4) that receives heat generated by the circuit board is integrally formed,
In the vehicle wireless communication device, the base plate is provided so as to have a portion within a predetermined nearby distance from the heat receiving element.

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