JP2010108874A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus capable of surely detecting grounding of a self-grounding terminal even in case of connecting with another electronic apparatus through a signal cable. <P>SOLUTION: In the electronic apparatus 1, a terminal section 4 integrally formed by sandwiching an insulator 4c by the grounding terminal 4a and a grounding detection terminal 4b is fixed on a body ground 9 by a screw 5 made of a conductor. When the terminal section 4 is fixed on the body ground 9, it is determined that the terminal section 4 is grounded at a μcom 6 since a detection line 3 connected with the grounding detection terminal 4b becomes at a low level. When the detection line 3 is at a high level, it is determined that the terminal section 4 is not grounded at the μcom 6. Then, the electronic apparatus 1 displays on a display section 8 that the terminal section is not grounded at the μcom. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device provided with a ground terminal for grounding a built-in electronic circuit.

  Electronic devices such as home appliances and in-vehicle devices are equipped with a grounding wire that is connected to the built-in electronic circuit and has a grounding terminal at the tip in order to ensure safety and ensure normal operation. Some terminals are used by being fixed to a grounding part such as a vehicle body (body earth) or the ground.

  For example, as shown in FIG. 1, the ground terminal is formed in a substantially U shape with a conductor such as metal, and a ground wire 102 is connected to the ground terminal 101, and a ground 103 such as a body ground is in contact with the screw 103. An electronic device (not shown) (an embedded electronic circuit) that is fixed and provided with the ground wire 102 is grounded.

In addition, as a detection device that detects whether or not an electronic device is grounded, for example, a detection device described in Patent Document 1 has been proposed. In Patent Document 1, it is detected whether a device is grounded by adding a circuit on an electronic circuit.
JP 2002-98726 A

  However, although the detection device described in Patent Document 1 can reliably detect grounding with a single device, for example, when constructing a system in which a plurality of electronic devices are connected with signal cables or the like, other devices are grounded. If so, the electronic circuit of the device is also electrically grounded through the signal cable, and detection on the electronic circuit may give a result different from the actual result.

  Furthermore, when using the grounding of other equipment through the signal cable, it is electrically grounded, but an excessive current flows through the signal cable, so the grounding wire in the signal cable is broken or the fuse is blown. May occur. Further, since the device itself is not grounded, the built-in electronic circuit is easily affected by noise and the like, and the designed performance may not be exhibited.

  Therefore, an object of the present invention is to provide an electronic device that can detect that its own ground terminal is reliably grounded even if it is connected to another electronic device with a signal cable.

  In order to solve the above-described problem, the electronic device according to claim 1 is an electronic device including a grounding member and a fixing unit made of a conductor for fixing the grounding member to a grounding portion, and the grounding member includes: A ground terminal formed of a conductor and connected to a ground line; and a ground detection terminal formed of a conductor and disposed via an insulator between the ground terminal and the ground member fixed And detecting means for detecting, via a detection line connected to the ground detection terminal, a change in signal level that occurs at the ground detection terminal when fixed to the ground portion by the means.

  Hereinafter, an electronic apparatus according to an embodiment of the present invention will be described. An electronic device according to an embodiment of the present invention includes a ground terminal in which a ground member is formed of a conductor, and a ground detection terminal that is also formed of a conductor and disposed between the ground terminal via an insulator. Since the detection means detects the fluctuation of the signal level generated at the ground detection terminal when the grounding member is fixed to the grounding portion by the fixing means, the detection means is connected via the detection line connected to the ground detection terminal. Since it is possible to detect whether or not the detection means is grounded according to the signal level of the detection line to which the detection terminal is connected, even if the device is connected to another device with a signal cable, etc. Can be prevented from being erroneously detected as its own ground, and it can be detected whether or not its own ground terminal is securely grounded.

  Further, the ground terminal and the ground detection terminal may be integrally provided so as to be electrically insulated from each other via an insulator. By doing so, the grounding member becomes an integral part, so that handling becomes easy.

  Moreover, you may provide the display means which displays the result detected by the detection means. By doing so, it is possible to take measures such as notifying the user or the like of the result detected by the detecting means and properly grounding.

  The detection means may include a pull-up resistor that maintains the signal level of the detection line at a high level when the ground detection terminal is not grounded. In this way, when not grounded, that is, when the input of the detection means is floating, the signal level is maintained at a high level to stabilize the input of the detection means and not grounded to the detection means. Can be reliably detected.

  An electronic apparatus 1 according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, the electronic device 1 includes a ground gland 2, a detection line 3, a terminal portion 4, a screw 5, μcom 6, a pull-up resistor 7, and a display portion 8.

  The ground wire 2 is connected to a ground terminal 4a of a terminal portion 4 to be described later at one end, and is connected to a ground wire of an electronic circuit built in an electronic device 1 (not shown) at the other end.

  The detection line 3 has one end connected to a ground detection terminal 4b of a terminal unit 4 to be described later, and the other end connected to μcom6.

  As shown in FIG. 2 and FIG. 3, the terminal portion 4 as a ground member is composed of a ground terminal 4a and a ground detection terminal 4b formed of a conductor such as metal, and an insulator 4c. The ground terminal 4a and the ground detection terminal 4b are formed in a substantially U shape, and are integrally configured with an insulator 4c interposed therebetween. That is, the terminal part 4 is comprised by the grounding terminal 4a and the grounding detection terminal 4b arrange | positioned through the grounding terminal 4a and the insulator 4c. The ground terminal 4a and the ground detection terminal 4b are not limited to a substantially U shape, and may be any shape that can be fixed with a screw 5 described later, such as an annular shape.

  The insulator 4c is formed so as to be sandwiched between the ground terminal 4a and the ground detection terminal 4b by rubber, resin, or the like, and also has an inner periphery so as to cover the U-shaped inner periphery of the ground terminal 4a and the ground detection terminal 4b. A portion 4c1 is formed. The inner peripheral portion 4c1 of the insulator 4c is recessed from the surfaces of the ground terminal 4a and the ground detection terminal 4b, and is formed so as not to contact the seat surface of the screw 5 or the body ground 9. By forming the insulator 4c in this way, the ground terminal 4a and the ground detection terminal 4b are electrically insulated from each other.

  The screw 5 as a fixing means is formed of a conductor such as metal, and fixes the terminal portion 4 so as to be in contact with the body ground 9. The fixing means is not limited to the screw 5 and a rivet or the like may be used. In short, any member may be used as long as it can fix the terminal portion 4 and electrically connect the ground terminal 4 a on the side not in contact with the body ground 9 to the body ground 9.

  Μcom 6 serving as a detection means is a microcomputer incorporating a CPU (Central Processing Unit), a memory, and the like. In this embodiment, the other end of the detection line 3 is connected and the terminal portion 4 is grounded. (Whether or not it is securely fixed to the body ground 9).

  The pull-up resistor 7 has one end connected to the vicinity of μcom 6 of the detection line 3 and the other end connected to the power supply voltage Vcc. When the terminal 4 is not grounded, the signal of the detection line 3 is connected. It is a resistor provided to maintain the level at a high level.

  The display unit 8 as a display means is provided for displaying and notifying a user or the like of the result detected by the μcom 6, and is configured by a liquid crystal display, a fluorescent display tube, or the like. Further, the display unit 8 may be an indicator such as an LED (Light Emitting Diode) that blinks or lights only when it is detected that it is not grounded.

  The body ground 9 is composed of a conductor such as a vehicle body, for example, and serves as a reference potential at which the electronic device 1 operates. If it is not a moving body such as a vehicle, it may be the ground or a conductor grounded to the ground.

  In this embodiment, when the terminal portion 4 is securely fixed to the body ground 9 with the screw 5 and the ground detection terminal 4b is in contact with the body ground 9, the detection line 3 becomes low level. When the ground detection terminal 4b is in contact with the body ground 9, the ground terminal 4a is also fastened and the seating surface of the screw 5 is in contact with the ground terminal 4a. Therefore, when the μcom 6 detects that the detection line 3 is at a low level, the terminal portion 4 It is determined that (ground terminal 4a) is grounded.

  When the ground detection terminal 4 b is not in contact with the body ground 9, the detection line 3 becomes high level due to the influence of the pull-up resistor 7. When the μcom 6 detects that the detection line 3 is at the high level, the μcom 6 determines that the terminal portion 4 is not grounded and displays a warning on the display portion 8 that it is not properly grounded.

  According to the present embodiment, the terminal portion 4 is configured such that the ground terminal 4a and the ground detection terminal 4b are integrally formed with the insulator 4c interposed therebetween, and is fixed by the screw 5 formed of a conductor. It can be determined whether or not the ground 5 is reliably grounded by the screw 5 based on whether or not the ground detection terminal 4b is grounded. Further, since the ground terminal 4a and the ground detection terminal 4b are integrally formed with the insulator 4c sandwiched therebetween, the terminal portion 4 can be handled almost the same as the conventional one.

  Further, since the grounding terminal 4a and the grounding detection terminal 4b sandwich the insulator 4c, for example, even if the grounding terminal 4a is connected to another grounded device 10 and the signal cable 11 as shown in FIG. Whether or not is grounded can be reliably detected. In the case of FIG. 4, even if the electronic device 1 is not grounded, the circuit of the electronic device 1 is also electrically grounded through the ground wire of the signal cable by the grounding of the other grounded device 10. In some cases, an excessive current may flow through the signal cable 11, which may cause the ground wire in the signal cable 11 to break or the fuse to melt. Furthermore, the circuit of the electronic device 1 is easily affected by noise and the like, and the performance as designed may not be exhibited. Therefore, by detecting that the ground detection terminal 4b is grounded by the μcom 6, it is possible to prevent the ground line in the signal cable 11 from being disconnected, the fuse from being blown, and the performance degradation due to noise.

  Further, since μcom 6 displays a warning indicating that the terminal unit 4 is not grounded when the terminal unit 4 is not grounded, it is possible to allow the user or the like to take measures such as properly grounding.

  Further, since the pull-up resistor 7 is connected to the detection line 3, the detection line 3 can be set to the high level when the terminal portion 4 is not grounded, the input of the μcom 6 is stabilized, and the μcom 6 is grounded. It is possible to reliably detect that it has not been performed.

  In the above-described embodiment, the terminal portion 4 has the ground terminal 4a and the ground detection terminal 4b integrally formed with the insulator 4c interposed therebetween. However, the ground terminal 4a, the insulator 4c, It may be fixed with the screw 5 after being overlapped in the order of the ground detection terminal 4b.

  According to the embodiment described above, the following electronic device 1 is obtained.

(Additional remark 1) It is the electronic device 1 which has the terminal part 4 and the screw 5 which consists of a conductor which fixes the terminal part 4 to the body earth | ground 9,
The terminal portion 4 is formed of a conductor, and a ground terminal 4a connected to the ground wire 2;
A ground detection terminal 4b formed of a conductor and disposed between the ground terminal 4a and an insulator 4c;
It is characterized by having μcom 6 for detecting a change in signal level generated in the ground detection terminal 4b when the terminal portion 4 is fixed to the body ground 9 with the screw 5 through the detection line 3 connected to the ground detection terminal 4b. Electronic device 1 to be used.

  According to the electronic device 1, since it can be detected that the μcom 6 is grounded via the detection line 3 to which the ground detection terminal is connected, the electronic device 1 is connected to other devices by a signal cable or the like. It is also possible to detect that its own terminal portion 4 is securely grounded.

  In addition, the Example mentioned above only showed the typical form of this invention, and this invention is not limited to an Example. That is, various modifications can be made without departing from the scope of the present invention.

It is the perspective view which showed the ground terminal concerning a prior art. It is a block diagram of the electronic device concerning one Example of this invention. FIG. 3 is a perspective view showing a terminal portion of the electronic device apparatus shown in FIG. 2. It is a block diagram which shows the case where it connects with another apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Grounding wire 3 Detection wire 4 Terminal part (grounding member)
4a Ground terminal 4b Ground detection terminal 4c Insulator 5 Screw (fixing means)
6 μcom (detection means)
7 Pull-up resistor 8 Display section (display means)
9 Body earth (grounding part)

Claims (4)

An electronic device having a grounding member and a fixing means made of a conductor for fixing the grounding member to the grounding part,
The ground member is formed of a conductor, and a ground terminal connected to a ground line;
A ground detection terminal formed of a conductor and disposed via an insulator between the ground terminal, and
And detecting means for detecting, via a detection line connected to the ground detection terminal, a change in signal level generated at the ground detection terminal when the ground member is fixed to the ground portion by the fixing means. Electronic equipment.   The electronic device according to claim 1, wherein the ground terminal and the ground detection terminal are integrally configured so as to be electrically insulated from each other via an insulator.   The electronic apparatus according to claim 1, further comprising a display unit that displays a result detected by the detection unit.   The detection unit includes a pull-up resistor that maintains a signal level of the detection line at a high level when the ground detection terminal is not grounded. The electronic device as described in the paragraph.

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