Vehicle antenna device

Abstract

To provide an antenna device for a vehicle which prevents an unintended force due to heat stress from affecting a circuit board on an antenna base and reduces limitations on the layout of the circuit board.SOLUTION: An antenna device for a vehicle is formed by: an antenna base 10; an antenna case 20; an antenna element 30; and a circuit board 40. The antenna base 10 is formed by: a resin base 11 and a conductive base 12. The antenna element 30 includes a power supply part 31. The circuit board 40 has the power supply part 31 of the antenna element 30 connected thereto, extends over the conductive base 12 of the antenna base 10, is fixed to the conductive base 12, and further extends over the resin base 11. When the antenna base 10 is fixed to the antenna case 20, the circuit board 40 is fixed by having at least a portion of the circuit board 40 extending over the resin base 11, sandwiched between the resin base 11 and the antenna case 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle antenna device, and more particularly to a vehicle antenna device that is fixed to a vehicle and houses a circuit board. [Background technology]

[0002] Vehicle antenna devices fixed to a vehicle generally have an antenna element capable of receiving AM and FM broadcasts. There are also small and low-profile antenna devices, such as so-called shark fin antennas, that house such antenna elements in an internal space. In recent years, vehicles have been made lighter in weight in consideration of fuel efficiency, as typified by electric cars and hybrid cars. Vehicle antenna devices are also required to be lighter, and resin-based vehicle antennas are being developed instead of conductive bases. For example, Patent Document 1 discloses a composite antenna base that combines a resin base and a conductive base. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 127903 Summary of the Invention [Problem to be solved by the invention]

[0004] A circuit board for mounting a connector for connecting a power supply part of an antenna element and an amplifier circuit for amplifying a received signal of the antenna element is fixed to the antenna base of a vehicle antenna device. When the circuit board extends from the conductive base onto the resin base and is fixed to each of the conductive base and the resin base, an inadvertent force due to thermal stress may be applied to the circuit board fixed to each of the conductive base and the resin base due to the difference in thermal expansion coefficient between the conductive base and the resin base. When such thermal stress is applied to the circuit board, there is a risk that the connector on the circuit board may be displaced, the wiring may be cut, or the circuit board may crack. For this reason, the circuit board cannot be made large, which limits the layout, or it is necessary to place the circuit board on each of the conductive base and the resin base.

[0005] Therefore, there has been a demand for the development of a vehicle antenna device in which no inadvertent force due to thermal stress is applied to the circuit board on the antenna base and which places fewer restrictions on the layout of the circuit board.

[0006] SUMMARY OF THE PRESENT EMBODIMENT In view of the above circumstances, the present invention provides a vehicle antenna device in which no inadvertent force due to thermal stress is applied to a circuit board on an antenna base and there are few limitations on the layout of the circuit board. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object of the present invention, the vehicle antenna device of the present invention comprises an antenna base consisting of a resin base and a conductive base, an antenna case fixed to the antenna base and defining an internal space together with the antenna base, an antenna element arranged in the internal space of the antenna case and having a power supply portion, and a circuit board to which the power supply portion of the antenna element is connected, extending over the conductive base of the antenna base and fixed to the conductive base and extending up to over the resin base, and when the antenna base is fixed to the antenna case, at least a portion of the circuit board extending over the resin base is sandwiched between the resin base and the antenna case, thereby fixing the circuit board.

[0008] Furthermore, the antenna base may be provided with a connection terminal mounted on a circuit board extending over the resin base of the antenna base and to which the power supply portion of the antenna element is connected.

[0009] Here, the antenna case may have a shark fin shape, and the connection terminal may be placed on the circuit board in the internal space near the short tip of the shark fin shape of the antenna case.

[0010] It may further include an amplifier circuit mounted on a circuit board extending over the conductive base of the antenna base.

[0011] The antenna element may be fixed to the antenna case.

[0012] In addition, the power supply portion of the antenna element may be made of a plate-shaped terminal having a plate-shaped flat portion, the surface direction of the flat portion of the plate-shaped terminal may be oriented in an axial direction passing from the low tip to the rear end of the shark fin shape, and the connection terminal may be made of a leaf spring terminal that clamps the surface of the flat portion of the plate-shaped terminal.

[0013] Furthermore, the antenna may be provided with a waterproof pad interposed between the antenna base and the antenna case for waterproofing the internal space, and at a position where at least a portion of the circuit board is sandwiched between the resin base and the antenna case, a portion of the waterproof pad may also be interposed between the resin base and the circuit board and / or between the antenna case and the circuit board. Effect of the Invention

[0014] The vehicle antenna device of the present invention has the advantages that no inadvertent force due to thermal stress is applied to the circuit board on the antenna base, and there are few restrictions on the layout of the circuit board. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic exploded perspective view for explaining a vehicle antenna device according to the present invention. [Diagram 2] FIG. 2 is a schematic enlarged cross-sectional side view for explaining details of a fixing portion of a circuit board of the vehicle antenna device of the present invention. [Diagram 3] FIG. 3 is a schematic enlarged perspective view for explaining details of a power supply portion and a connection terminal of the antenna element of the vehicle antenna device of the present invention. [Figure 4] FIG. 4 is a schematic enlarged perspective view for explaining details of the waterproof pad of the vehicle antenna device of the present invention. [Diagram 5] FIG. 5 is a schematic enlarged cross-sectional side view of a waterproof pad of the vehicle antenna device of the present invention, corresponding to FIG. [Figure 6] FIG. 6 is a schematic enlarged cross-sectional side view for explaining details of another waterproof pad of the vehicle antenna device of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The vehicle antenna device of the present invention has an antenna element covered with a housing fixed to a vehicle. An example of application to a low-profile roof-mounted antenna device will be specifically described below. As long as the antenna element covered with a housing is fixed to a vehicle, the fixing position is not limited to the roof-mounted antenna device, and may be, for example, a dashboard antenna device, or the like.

[0017] 1 is a schematic exploded perspective view for explaining the vehicle antenna device of the present invention. As shown in the figure, the vehicle antenna device of the present invention is mainly composed of an antenna base 10, an antenna case 20, an antenna element 30, and a circuit board 40. Note that the shapes of the components in the illustrated example are merely examples and are disclosed for the purpose of explanation, and the vehicle antenna device of the present invention is not limited to these shapes.

[0018] The antenna base 10 is made up of a resin base 11 and a conductive base 12. It is a so-called composite antenna base. In the illustrated example, the antenna base 10 has a through hole provided near the center of the resin base 11, and the conductive base 12 is configured to fit into the through hole. The resin base 11 fits into an opening of an antenna case 20 described below so as to close the opening. The resin base 11 and the antenna case 20 may be fixed by, for example, a screw 23. The conductive base 12 serves as the ground of a circuit board 40 described below. More specifically, the conductive base 12 is provided with, for example, a screw boss, which is inserted into a through hole provided in the vehicle roof and fixed by a nut or the like, and is electrically connected to the vehicle roof.

[0019] The antenna case 20 is fixed to the antenna base 10 and defines an internal space together with the antenna base 10. An antenna element 30 and a circuit board 40, which will be described later, are housed in the internal space of the antenna case 20. The antenna case 20 in the illustrated example has a so-called shark fin shape. However, the present invention is not limited to this, and any shape having an internal space, such as a triangular or rectangular shape, may be used. The antenna case 20 may also be a double cover using an inner cover and an outer cover.

[0020] The antenna element 30 is disposed in the internal space of the antenna case 20. The antenna element 30 may be, for example, for use in a radio. The antenna element 30 in the illustrated example is an umbrella-shaped antenna element, which is a so-called top-loaded antenna element. However, the present invention is not limited to this, and any shape that functions as an antenna element, such as a flat plate shape or a meander shape, may be used. The antenna element 30 also has a power supply unit 31. The power supply unit 31 in the illustrated example is disposed on the low tip side of the antenna case 20. However, the present invention is not limited to this, and the power supply unit 31 may be disposed in the center or rear end side of the antenna element 30.

[0021] The circuit board 40 is connected to the power supply unit 31 of the antenna element 30. The circuit board 40 extends over the conductive base 12 of the antenna base 10 and is fixed to the conductive base 12, and also extends over the resin base 11. That is, the circuit board 40 extends from the conductive base 12 to the resin base 11. The circuit board 40 is fixed to the conductive base 12, for example, by screws 13. The ground of the circuit board 40 is electrically connected to the conductive base 12, for example, via the screws 13, so that the vehicle roof becomes the ground. On the other hand, as described below, the circuit board 40 is not fixed to the resin base 11 by the screws 13. That is, when the antenna base 10 is fixed to the antenna case 20, at least a part of the circuit board 40 extending over the resin base 11 is sandwiched between the resin base 11 and the antenna case 20, and thus fixed.

[0022] Hereinafter, a more detailed description will be given with reference to FIG. 2. FIG. 2 is a schematic enlarged side cross-sectional view for explaining the details of the fixing portion of the circuit board of the vehicle antenna device of the present invention. In the figure, the parts with the same reference numerals as those in FIG. 1 represent the same objects. As shown in the figure, the antenna case 20 is fixed to the antenna base 10, for example, by a screw 23. At this time, the circuit board 40 extending on the resin base 11 is sandwiched and fixed between the fixing convex portion 15 provided on the resin base 11 and the fixing rib 25 provided on the antenna case 20. That is, the circuit board 40 is fixed by sandwiching the front and back surfaces of the circuit board 40 between the fixing convex portion 15 and the fixing rib 25. Since the front and back surfaces of the circuit board 40 are sandwiched between the fixing convex portion 15 and the fixing rib 25 on the resin base 11, the circuit board 40 is fixed so as to be slidable in the horizontal direction. On the other hand, the circuit board on the conductive base 12 is fixed to the conductive base 12 by the screw 13 and does not move in the horizontal direction. In this way, the circuit board 40 is fixed to the conductive base 12, while being slidably fixed on the resin base 11. Therefore, even if the thermal expansion coefficients of the resin base 11 and the conductive base 12 are different and the resin base 11 or the conductive base 12 expands or contracts in the horizontal direction due to thermal changes, an inadvertent force due to thermal stress is not applied to the circuit board 40. It is more effective to fix the circuit board 40 on the resin base 11 at a position that allows sliding in the longitudinal direction, where the expansion and contraction of the resin base 11 and the conductive base 12 are more affected.

[0023] In the illustrated example described above, the circuit board 40 is sandwiched between the fixing protrusions 15 and the fixing ribs 25, but the present invention is not limited to this. The circuit board 40 may be sandwiched between the protrusions, for example, as long as it is sandwiched and fixed between the antenna base 10 and the antenna case 20. The fixing of the antenna base 10 and the antenna case 20 is not limited to being fixed by the screws 23, and may be fixed by engagement claws or the like.

[0024] Also, the antenna element 30 may be fixed to the antenna base side using a support member or the like. Then, the power supply unit 31 of the antenna element 30 may be directly connected to the circuit board 40. Furthermore, the antenna element 30 may be fixed to the antenna case 20. Then, as shown in Fig. 2, a connection terminal 41 to which the power supply unit 31 of the antenna element 30 is connected may be placed on the circuit board 40.

[0025] As described above, in the conventional technology, the circuit board had to be arranged and fixed only on the conductive base so that inadvertent force due to thermal stress would not be applied to the circuit board. Therefore, even if it was desired to arrange the connection terminal at the short end side of the antenna case, it was not possible to do so because there was no circuit board. However, in the vehicle antenna device of the present invention, since inadvertent force due to thermal stress is not applied to the circuit board 40, it is possible to extend the circuit board to any position. Therefore, for example, when the antenna case 20 is shark fin shaped, it is possible to extend the circuit board 40 to the vicinity of the short end of the shark fin shape. Therefore, it is possible to place the connection terminal 41 on the circuit board 40 in the internal space near the short end of the shark fin shape. In this way, there are fewer restrictions on the layout of the circuit board 40.

[0026] Furthermore, an amplifier circuit 42 may be mounted on the circuit board 40. Since the amplifier circuit 42 requires a ground, it is preferable that the amplifier circuit 42 is mounted on the circuit board 40 extending above the conductive base 12. Since the ground of the circuit board 40 is electrically connected to the conductive base 12, it is preferable that the amplifier circuit 42 is mounted in a position close to the conductive base 12. In this case, the connection terminal 41 is disposed near the short tip of the shark fin shape, and the amplifier circuit 42 is disposed on the circuit board 40 extending above the conductive base 12 in the portion covered by the antenna element 30.

[0027] Next, the power supply part and the connection terminal of the antenna element of the vehicle antenna device of the present invention will be described in detail with reference to FIG. 3. FIG. 3 is a schematic enlarged perspective view for explaining the power supply part and the connection terminal of the antenna element of the vehicle antenna device of the present invention in detail. In the figure, the parts with the same reference numerals as in FIG. 1 represent the same objects. Also, only the power supply part 31 and the periphery of the connection terminal 41 are shown, and the other parts are omitted from the illustration. The power supply part 31 of the antenna element 30 may be, for example, a plate-shaped terminal having a plate-shaped flat part. In this case, as shown in the figure, the surface direction of the flat part of the plate-shaped terminal may be configured to face the axial direction passing from the low tip to the rear end of the shark fin shape. And the connection terminal 41 may be a leaf spring terminal that sandwiches the surface of the flat part of the plate-shaped terminal. That is, the sandwiching groove of the connection terminal 41 also faces the axial direction passing from the low tip to the rear end of the shark fin shape. The plate-shaped terminal of the power supply unit 31 is sandwiched between the connection terminals 41, which are leaf spring terminals, so as to be slidable in the longitudinal direction of the antenna base 10.

[0028] 3, if the power supply unit 31 and the connection terminal 41 are configured to be slidable in the longitudinal direction of the antenna base 10, even if the resin base 11 and the conductive base 12 expand and contract in the longitudinal direction, which is more affected by thermal changes, and the position of the circuit board 40 shifts relative to the antenna element 30 fixed to the antenna case 20, it is possible to prevent poor contact due to inadvertent application of force due to thermal stress. In other words, inadvertent force due to thermal stress of the antenna base 10 is not applied between the power supply unit 31 and the connection terminal 41. On the other hand, as described above, the circuit board 40 on the resin base 11 is sandwiched between the fixing protrusion 15 and the fixing rib 25, and is therefore stably fixed at least in the vertical direction, and therefore does not slide in the vertical direction between the power supply unit 31 and the connection terminal 41.

[0029] Furthermore, the vehicle antenna device of the present invention may have a waterproof pad 50 as shown in Fig. 2. The waterproof pad 50 is interposed between the antenna base 10 and the antenna case 20 to waterproof the internal space and to waterproof the space between the vehicle roof and the antenna base 10. The waterproof pad 50 is configured to cover, for example, the lower part (vehicle roof side) of the antenna base 10 and extend from the side to the contact part with the antenna case 20. That is, the waterproof pad 50 may be configured to cover the antenna base 10.

[0030] A part of the waterproof pad 50 may be configured to be interposed between the resin base 11 and the circuit board 40. FIG. 4 is a schematic enlarged perspective view for explaining the details of the waterproof pad of the vehicle antenna device of the present invention. FIG. 5 is a schematic enlarged side sectional view of the waterproof pad corresponding to FIG. 4 of the vehicle antenna device of the present invention. In the figure, the parts with the same reference numerals as in FIG. 2 represent the same objects. Also, only the periphery of the fixing convex portion 15 and the fixing rib 25 is shown, and the other parts are omitted from the illustration. As shown in the figure, a part of the waterproof pad 50 is configured as a spacer portion 51 processed so as to cover the convex portion of the fixing convex portion 15. That is, the spacer portion 51 of the waterproof pad 50 is configured to be interposed between the fixing convex portion 15 of the resin base 11 and the circuit board 40 at the position where the circuit board 40 is sandwiched between the fixing convex portion 15 of the resin base 11 and the fixing rib 25 of the antenna case 20. With this configuration, even if there is a design error in the gap when the circuit board 40 is sandwiched between the fixing protrusions 15 and the fixing ribs 25, the error can be absorbed by the spacer portions 51.

[0031] FIG. 6 is a schematic enlarged side cross-sectional view for explaining the details of another waterproof pad of the vehicle antenna device of the present invention. In the figure, the parts with the same reference numerals as those in FIG. 2 represent the same objects. Also, only the periphery of the fixing convex portion 15 and the fixing rib 25 is shown, and the other parts are omitted. As shown in the figure, in this example, the spacer portion 52 of the waterproof pad 50 is configured to be interposed between the fixing rib 25 of the antenna case 20 and the circuit board 40 at the position where the circuit board 40 is sandwiched between the fixing convex portion 15 of the resin base 11 and the fixing rib 25 of the antenna case 20. The spacer portion 52 may be configured to extend from the side end portion to the upper surface of the circuit board 40, for example. For example, after the circuit board 40 is fixed to the antenna base 10, the waterproof pad 50 is provided so as to cover the antenna base 10. At this time, the spacer portion 52 is configured to be disposed at the position of the upper surface of the circuit board 40 sandwiched between the fixing convex portion 15 and the fixing rib 25. Even if configured in this manner, when the circuit board 40 is sandwiched between the fixing protrusions 15 and the fixing ribs 25, even if there is a design error in the gap, the error can be absorbed by the spacer portion 52. Note that the spacer portion 51 shown in Fig. 5 and the spacer portion 52 shown in Fig. 6 may be combined. In other words, a part of the waterproof pad 50 may be configured to be interposed between the resin base 11 and the circuit board 40, and between the antenna case 20 and the circuit board 40.

[0032] The vehicle antenna device of the present invention is not limited to the above-mentioned illustrated example, and it is needless to say that various modifications can be made without departing from the gist of the present invention. [Explanation of symbols]

[0033] 10 Antenna Base 11 Resin-based 12 Conductive base 13 Screw 15 Fixing protrusion 20 Antenna case 23 Screw 25 Fixing rib 30 Antenna Element 31 Power supply unit 40 Circuit Board 41 Connection terminal 42 Amplifier circuit 50 Waterproof Pad 51 Spacer part 52 Spacer part

Claims

1. A vehicle antenna device fixed to a vehicle, the vehicle antenna device comprising: an antenna base consisting of a resin base and a conductive base; an antenna case fixed to the antenna base and defining an internal space together with the antenna base; an antenna element disposed in an internal space of the antenna case and having a power supply portion; a circuit board to which a power supply portion of the antenna element is connected, which extends over and is fixed to a conductive base of the antenna base and also extends over a resin base, and when the antenna base is fixed to the antenna case, at least a portion of the circuit board extending over the resin base is sandwiched between the resin base and the antenna case, thereby being fixed; A vehicle antenna device comprising:

2. 2. The vehicle antenna device according to claim 1, further comprising a connection terminal mounted on a circuit board extending above the resin base of the antenna base and to which a power supply portion of the antenna element is connected.

3. 3. The vehicle antenna device according to claim 2, The antenna case has a shark fin shape, The connection terminal is placed on a circuit board in the internal space near the low tip of the shark fin shape of the antenna case.

2. A vehicle antenna device comprising:

4. 4. The vehicle antenna device according to claim 3, further comprising an amplifier circuit mounted on a circuit board extending over the conductive base of the antenna base.

5. 5. The vehicle antenna device according to claim 4, wherein the antenna element is fixed to an antenna case.

6. 6. The vehicle antenna device according to claim 5, The power supply portion of the antenna element is made of a plate-like terminal having a plate-like flat portion, and the surface direction of the flat portion of the plate-like terminal is oriented in an axial direction passing from the low front end to the rear end of the shark fin shape, The connection terminal is a leaf spring terminal that pinches the surface of the flat portion of the plate-shaped terminal.

2. A vehicle antenna device comprising:

7. 7. A vehicle antenna device according to claim 1, Further, a waterproof pad is provided between the antenna base and the antenna case to waterproof the internal space, At a position where at least a part of the circuit board is sandwiched between the resin base and the antenna case, a part of the waterproof pad is also interposed between the resin base and the circuit board and / or between the antenna case and the circuit board.

2. A vehicle antenna device comprising:

Images