JPH0531337U - In-vehicle electronic device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a low-cost in-vehicle electronic device which has improved electromagnetic wave resistance, is easily assembled in a restricted mounting space, and has a small number of parts. [Constitution] In a vehicle-mounted electronic device, a connector pin 3b
A conductive wall member 1f disposed in the conductive case 1a so as to surround the bypass capacitor 4 and the bypass capacitor 4, and a mounting substrate 2a.
A conductor pattern region 2f forming a storage region surrounding the connector pin 3b and the bypass capacitor 4 in cooperation with the wall member 1f is provided on the surface, and the wall member 1f and the conductor pattern region 2f are connected to the conductive case 1a. Set to the same potential. Also,
An LC filter is used instead of the bypass capacitor 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle-mounted electronic device, and more particularly to a vehicle-mounted electronic device provided with measures against radio interference.

[0002]

[Prior art]

 Conventionally, as this type of vehicle-mounted electronic device, for example, one disclosed in Japanese Patent Publication No. 63-23018 is known.

FIG. 6 is an exploded perspective view showing an example of such a conventional vehicle-mounted electronic device. In FIG. 6, both the conductive case 1a and the lid 1b are made of an electrically conductive material such as aluminum or iron. Reference numeral 3b denotes a connector pin provided so as to be inserted into the connector housing 3a, and one side thereof is connected to a through hole 3c on the printed circuit board 2a which is enclosed and housed in the conductive case 1a. One end of the bypass capacitor 4 is connected to the connector pin 3b via the copper foil pattern 3d.

A copper foil pattern 3e is provided on the printed circuit board 2a so as to extend close to the copper foil pattern 3d as shown in the figure, and the other terminal of the bypass capacitor 4 is provided. Connected. The pattern 3e is electrically connected to the conductive case 1a by a printed board mounting screw 1c.

In such a configuration, the electromagnetic wave emitted from the outside of the conductive case 1a becomes a high frequency wave, enters the conductive case 1a through the connector pin 3b, and enters the conductive case 1a through the bypass capacitor 4 and the pattern 3e. Flows. Therefore, the high frequency current does not flow into the electronic circuit including the electronic elements 2b and 2c mounted on the printed circuit board 2a, and the malfunction of the electronic circuit can be prevented.

[0006]

[Problems to be solved by the device]

 FIG. 7 is a diagram showing electromagnetic wave resistance of the conventional vehicle-mounted electronic device shown in FIG. In FIG. 7, the horizontal axis represents frequency and the vertical axis represents electric field strength (electromagnetic wave resistance characteristic). As is clear from FIG. 7, when an electromagnetic wave having an output of 40 watts was irradiated, it was found that there was a frequency band in which the electromagnetic wave resistance was extremely weak in a certain frequency band.

If there is a frequency band in which the electromagnetic wave resistance is extremely weak as described above, there is a problem that the electronic circuit in the vehicle-mounted electronic device malfunctions in this frequency band. From this point of view, considering the use environment for in-vehicle use, there is an urgent need to develop an in-vehicle electronic device that is technically excellent in electromagnetic wave resistance.

The present invention has been made in order to solve the problem that the above-mentioned electromagnetic wave resistance characteristics cannot be satisfied by the conventional in-vehicle electronic device. Therefore, the electromagnetic wave resistance characteristics are improved and the mounting space is restricted. It is an object of the present invention to provide a low-cost electronic device for automobiles, which is housed inside and has a good assembling property and a small number of parts.

[0009]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a mounting board 2a on which an electronic circuit is mounted, a conductive case 1a surrounding and housing the mounting board 2a, an electronic circuit and a conductive case 1a, as shown in FIG. And a connector pin 3b pulled out to the outside of the conductive case 1a for transmitting signals to and from the outside of the conductive case 1a, and a conductive member of one end connected to the connector pin and the other end on the mounting substrate 2a which is the conductive case 1a. An on-vehicle electronic device, which is connected to the device 3e connected to, and is equipped with a bypass capacitor 4 mounted on the mounting substrate 2a so as to be located in the vicinity of the outlet of the connector pin 3b. A conductive wall member 1f arranged in the conductive case 1a so as to surround the pin 3b and the bypass capacitor 4, and a conductive wall member on the surface of the mounting substrate 2a in contact with the conductive wall member 1f. A conductor pattern region 2f forming a storage region surrounding the connector pin 3b and the bypass capacitor 4 in cooperation with f is provided, and the wall member 1f and the conductor pattern region 2f are set to the same potential as the conductive case 1a. It is characterized by doing.

(2) Further, instead of the bypass capacitor 4, as shown in FIG. 4, first and second coil elements 5a and 5c and a capacitor element 5b are provided, and one end of each of the first and second coil elements is An L-C filter 5 is used, which is connected to each other and one end of a capacitor element 5b is connected to the connection portion. One end of a connector pin is connected to the other end of the first coil element 5a of the L-C filter 5. The second coil element 5c, the other end of the second coil element 5c is connected to the one end of the connector pin 3b, and the other end of the capacitor element 5b is a conductive member on the mounting board, which is the conductive case 1a. It is characterized in that it is connected to one 3e connected to.

[0011]

[Action]

 In the invention of (1) above, the connector pin 3b and the bypass capacitor 4 are surrounded by the conductive wall member 1f having the same potential as the conductive case 1a, so that the input / output line is connected via the connector pin 3b of the electronic device. Since the high frequency current induced in the electric field is bypassed to the conductive case 1a through the bypass capacitor 4 and the conductive wall member 1f, the high frequency current is higher than that of the vehicle-mounted electronic device having the conventional structure as described later. Bypass effect, that is, electromagnetic wave resistance is improved.

Further, in the invention of (2), by using the LC filter 5 instead of the bypass capacitor, the high frequency current induced in the input / output line via the connector pin 3b of the electronic device will be described in detail later. As described above, since it is bypassed to the conductive case 1a through the capacitor element 5b of the LC filter 5, the bypass effect of the high-frequency current, that is, the resistance to high-frequency current is improved as compared with the vehicle-mounted electronic device having the conventional structure, as will be described later. The electromagnetic wave characteristics are improved.

Further, in the invention of (2), as described in detail later, as in the invention of (1), the connector pin 3b and the bypass capacitor 4 are surrounded by the conductive case 1a and the conductive wall member 1f of the conductive level. Even if it is not provided, since the electromagnetic wave resistance characteristic is superior to that of the invention of (1), the conductive wall member 1f is unnecessary, and the structure is simpler than that of the invention of (1).

[0014]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 is an exploded perspective view showing an example of a vehicle-mounted electronic device according to the first aspect of the invention. In FIG. 1, the same components as those of the conventional vehicle-mounted electronic device of FIG. 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the vehicle-mounted electronic device of FIG. 1, the mounting space is reduced by using a block capacitor for the bypass capacitor 4 for high frequency current. The bypass capacitor 4, which is the block capacitor, can be electrically connected to the conductive case 1a by connecting the common terminal 4a to the fixing screw mounting portion 2e of the printed circuit board 2a by the pattern 3e. The other terminals 4b are connected to the respective terminals of the connector pin 3b through a pattern 3d and through holes 3c. The bypass capacitor 4 is mounted on the printed board 2a close to the connector pin 3b. Both the connector pin 3b and the bypass capacitor 4 are enclosed and housed in the conductive case 1a by a conductive wall member 1f provided so as to partition the same.

On the other hand, a pattern contacting the conductive case is provided in the pattern region 2f on the surface of the printed circuit board 2a that is surrounded by the conductive wall member 1f and that contacts the connector pins 3b. Immediately, a copper foil pattern except the through hole 3c is left on the back surface of the hatched portion of FIG. 1 and used as the pattern area 2f.

With such a configuration, the connector pin 3b and the bypass capacitor 4 are housed in the housing area composed of the conductive wall member 1f and the pattern area 2f provided in the conductive case 1a. ..

In the vehicle-mounted electronic device having the above structure, the high frequency current induced in the input / output line through the connector pin 3b is bypassed to the conductive case 1a through the bypass capacitor 4 and the conductive wall member 1f. Therefore, as compared with the vehicle-mounted electronic device having the conventional structure shown in FIG. 6, the bypass effect of the high frequency current, that is, the electromagnetic wave resistance is improved.

FIG. 2 is a diagram showing the electromagnetic wave resistance of the vehicle-mounted electronic device of FIG. As is clear from comparison between FIG. 2 and FIG. 7, it can be seen that this vehicle-mounted electronic device has improved electromagnetic wave resistance characteristics as compared with the vehicle-mounted electronic device of the conventional structure shown in FIG. In FIG. 2, the horizontal axis represents frequency and the vertical axis represents electric field strength (electromagnetic wave resistance).

Second Embodiment FIG. 3 is an exploded perspective view showing an example of a vehicle-mounted electronic device according to the second aspect of the invention. In FIG. 3, the same parts as those of the vehicle-mounted electronic device of FIGS. 1 and 6 are designated by the same reference numerals, and detailed description thereof will be omitted.

The main difference between the on-vehicle electronic device of FIG. 3 and the on-vehicle electronic device of FIG. 1 is that the on-vehicle electronic device of FIG. 3 uses the LC filter 5 instead of the bypass capacitor 4 and the conductivity. That is, the conductive wall member 1f provided in the flexible case 1a is not provided. The LC filter 5 includes a first coil element 5a, a second coil element 5c and a capacitor element 5b as shown in the equivalent circuit of FIG. 4, and the first coil element 5a and the second coil element 5a are included. One ends of the capacitors 5c are connected to each other, and one end of the capacitor element 5b is connected to the connecting portion. The LC filters 5 are provided by the number of connector pins 3b (three in FIG. 3).

Then, as shown in FIG. 3, the other ends 5at of the first coil elements 5a of the plurality of LC filters 5 are respectively connected to electronic circuits for transmitting signals by the connector pins 3b through through holes 3c and the like. The other end 5ct of the second coil element 5c is connected to the connector pin 3b through the through hole 3c and the pattern 3d, and the other end 5bt of the capacitor element 5b is on the printed circuit board 2a. Connect to the common pattern 3e. The pattern 3e is connected to the conductive case 1a via a screw 1c for fixing to the printed board 2a and a mounting hole 3f and is grounded. The pattern 3d is formed as short as possible.

In the vehicle-mounted electronic device having the above configuration, the high frequency current induced in the input / output line via the connector pin 3b is bypassed to the conductive case 1a through the capacitor element 5b of the LC filter 5. As compared with the vehicle-mounted electronic device having the conventional structure shown in FIG. 6, the bypass effect of the high frequency current, that is, the electromagnetic wave resistance is improved.

FIG. 5 is a diagram showing the electromagnetic wave resistance of the vehicle-mounted electronic device of FIG. As is clear from comparison between FIG. 5 and FIG. 7, it can be seen that the in-vehicle electronic device of the present invention has improved electromagnetic wave resistance characteristics as compared with the in-vehicle electronic device of the conventional structure. Further, as is clear from comparison between FIG. 5 and FIG. 2, it can be seen that this vehicle-mounted electronic device has improved electromagnetic wave resistance characteristics as compared with the vehicle-mounted electronic device of FIG. In FIG. 5, the horizontal axis represents frequency and the vertical axis represents electric field strength (electromagnetic wave resistance).

5 is similar to the vehicle-mounted electronic device of FIG. 1, the connector pin 3b and the bypass capacitor 4 are surrounded by the conductive wall member 1f having the same potential as the conductive case 1a. Even if it is not provided, since the electromagnetic wave resistance is superior to that of the vehicle-mounted electronic device of FIG. 1, the conductive wall member 1f is unnecessary and the structure becomes simpler.

[0026]

[Effect of the device]

 (1) According to the invention of claim 1 of the present application as described above based on the embodiments, the housing area is provided in the conductive case so that the connector pin and the bypass capacitor are surrounded by the conductive wall member. , The high frequency current induced in the input / output line of the electronic device is bypassed to the conductive case through the conductive wall member in this storage area before it gets into the electronic circuit, and thus the electromagnetic wave resistance is improved. To do.

(2) Further, when the case is made of die-cast, the housing area surrounding the connector and the bypass capacitor can be integrally molded, so that the assembling performance is good, and the number of extra parts is not increased and the cost is reduced. Can realize an advantageous on-vehicle electronic device.

(3) According to the invention of claim 2 of the present application, by using the LC filter instead of the bypass capacitor, the high frequency current induced in the input / output line via the connector pin of the electronic device is , By bypassing to the conductive case through the capacitor element 5b of the LC filter 5, the electromagnetic wave resistance is significantly improved.

(4) According to the invention of claim 2, even when the connector pin 3b and the bypass capacitor are not surrounded by the conductive wall member having the same potential as the conductive case as in the invention of claim 1, Since the electromagnetic wave resistance is superior to that of the first invention, the conductive wall member is unnecessary and the structure becomes simpler.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a vehicle-mounted electronic device according to an embodiment of the present invention.

FIG. 2 is a diagram showing electromagnetic wave resistance of the vehicle-mounted electronic device of FIG.

FIG. 3 is an exploded perspective view of an in-vehicle electronic device according to an embodiment of the present invention.

FIG. 4 is a diagram showing an equivalent circuit of an LC filter 5.

5 is a diagram showing electromagnetic wave resistance characteristics of the vehicle-mounted electronic device of FIG.

FIG. 6 is an exploded perspective view of a conventional vehicle-mounted electronic device.

FIG. 7 is a diagram showing electromagnetic wave resistance characteristics of the vehicle-mounted electronic device of FIG.

[Explanation of symbols]

 1a conductive case 1b lid 1c mounting screw 1d mounting screw 1e mounting screw 1f conductive wall member 2a printed circuit board 2b electronic element 2c electronic element 3a connector housing 3b connector pin 3c through hole 3d pattern 3e pattern 3f mounting hole 4 bypass capacitor 5 L -C filter 5a coil element 5b capacitor element 5c coil element

Claims (2)

[Scope of utility model registration request] 1. A mounting board on which an electronic circuit is mounted, a conductive case surrounding and housing the mounting board, and the conductive case for performing signal transmission between the electronic circuit and the outside of the conductive case. With the connector pin pulled out of the
The one end is connected to the connector pin and the other end is connected to a conductive member on the mounting board, which is connected to the conductive case, and the mounting is performed so as to be located in the vicinity of the outlet of the connector pin. In a vehicle-mounted electronic device comprising a bypass capacitor mounted on a substrate, a conductive wall member disposed in the conductive case so as to surround the connector pin and the bypass capacitor, and the conductive wall. A conductor pattern region forming a storage region surrounding the connector pin and the bypass capacitor in cooperation with the conductive wall member is provided on the surface of the mounting substrate in contact with the member, and the conductor wall member and the conductor are provided. An in-vehicle electronic device, wherein the pattern region and the conductive case have the same potential. 2. A mounting board on which an electronic circuit is mounted, a conductive case surrounding and housing the mounting board, and the conductive case for transmitting signals between the electronic circuit and the outside of the conductive case. With the connector pin pulled out of the
The one end is connected to the connector pin and the other end is connected to a conductive member on the mounting board, which is connected to the conductive case, and the mounting is performed so as to be located in the vicinity of the outlet of the connector pin. An on-vehicle electronic device comprising a bypass capacitor mounted on a substrate, comprising first and second coil elements and a capacitor element in place of the bypass capacitor, and one end of the first and second coil elements. Are connected to each other, and one end of a capacitor element is connected to the connection part.
The other end of the first coil element of the filter is connected to the electronic circuit to which one end of the connector pin is connected, the other end of the second coil element is connected to the one end of the connector pin, and the capacitor element is further connected. The other end is connected to a conductive member on the mounting board, which is connected to the conductive case.