JP2704483B2 - Current detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detecting device for detecting a load current of a battery of an automobile, for example.

[0002]

2. Description of the Related Art Conventionally, such a current detecting device is configured, for example, as shown in FIG. That is, FIG.
, The current detecting device 1 includes a case 5 having a through portion 5a through which the connection cord 4 to the load 3 connected to the battery 2 is inserted, and is housed in the case so as to surround the through portion 5a of the case 5. Ring-shaped core 6 (see FIG. 12)
And a Hall element 7 disposed in the gap 6a of the core 6.
And a printed circuit board 8 on which a power supply circuit for supplying a predetermined current to the Hall element 7 together with the Hall element 7 and an amplifier circuit for amplifying the Hall voltage of the Hall element are mounted.

According to the current detecting device 1 configured as described above, the current flowing through the Hall element is set to a predetermined value by the power supply circuit, and based on the current flowing through the connection cord 4, the action of the core 6 causes the current to flow. The magnetic flux passes through the gap 6a, and the Hall voltage of the Hall element 7 is uniquely determined according to the magnetic flux. After the Hall voltage is amplified by the amplifier circuit, it is output to the outside from the output terminal 9 and appropriately processed, whereby the current flowing through the connection cord 4 can be detected.

[0004]

However, in the current detection device 1 having such a configuration, it is necessary to accurately position the fixed arrangement of the core 6 in the case 5 and the positioning of the Hall element 7 with respect to the gap of the core 6. Therefore, there is a problem that the number of components such as the mounting member increases, the structure becomes complicated, and the cost increases. Further, since it is necessary to electromagnetically shield circuit parts such as the Hall element, the power supply circuit, and the amplifier circuit, the structure becomes more complicated, and since the shield member needs to be connected to ground, the assembly becomes complicated. There was also a problem that it would be. Furthermore, when detecting large current and small current,
As for the small current, the Hall voltage is very low, so that the detection accuracy is not very good.

In view of the above, the present invention makes it possible to easily assemble with a simple structure, and to easily electromagnetically shield a circuit portion. It is an object of the present invention to provide a current detection device capable of reliably detecting a current.

[0006]

In order to achieve the above object, according to the present invention, there is provided a case having a through portion through which an electric wire through which a current to be detected flows is inserted, and a case inside the case surrounding the through portion of the case. A ring-shaped core with a gap housed in the core element and a Hall element disposed in the gap of the core,
A current detector including a power supply circuit for flowing a predetermined current to the Hall element and an amplifier circuit for amplifying a Hall voltage of the Hall element; wherein the Hall element, the power supply circuit and the amplifier circuit are mounted on a printed circuit board; A shield member made of a substantially rectangular parallelepiped non-magnetic conductor having an open surface and a shield cover having one edge connected to one side edge of the open surface of the shield member are provided along the inner surface of the shield member. A claw portion which is covered by the shield member so as to close the open surface of the shield member, and protrudes upward from another side edge other than the side edge to which the shield cover of the open surface of the shield member is connected. Is bent over the shield cover and soldered, so that the inside of the case is shielded.

Further, according to the present invention, there is provided a case having a through portion through which an electric wire through which a current to be detected flows is inserted, and a ring-shaped gap housed in the case so as to surround the through portion of the case. A hall element disposed in a gap between the core, a power supply circuit for supplying a predetermined current to the hall element, and an amplification circuit for amplifying a hall voltage of the hall element; In the current detection device mounted on the printed circuit board, the connection pin drawn into the case is upright in the case after passing through the shield member through the feedthrough capacitor, and the connection through hole for the printed circuit board is connected. In addition to being able to be directly soldered to the hole, of the connection pins, the connection pin for ground is connected to the shield member via a short-type feedthrough capacitor. Characterized in that it is connected to the passage to and shielding member.

In the current detecting device according to the present invention, preferably, a plurality of terminals made of a U-shaped conductor are embedded integrally in a portion of the case where the core is to be accommodated, and the core is embedded in the case. After that, a connection printed circuit board having a pattern for sequentially connecting the inner end of each terminal and the outer end of the adjacent terminal is placed thereon, and the core is formed a plurality of times by the terminals and the printed circuit board pattern. It has a coil to wind.

[0009]

According to the above construction, a shield member made of a substantially rectangular parallelepiped non-magnetic conductor having an open surface along the inner surface of the case, and a shield cover having one edge connected to the side edge of the shield member And the shield cover is put on the shield member so as to close the open surface of the shield member, and a claw projecting upward from a side edge of the shield member is bent on the shield cover and soldered. You. Therefore, since the inside of the case is shielded, electromagnetic shielding can be easily performed with a simple configuration.

Further, the connection pin drawn into the case is upright in the case after passing through the shield member via the feedthrough capacitor, and can be directly soldered to the connection through hole of the printed circuit board. Among the connection pins, a connection pin for grounding passes through the shield member and is connected to the shield member via a short-type feedthrough capacitor. Therefore, by soldering the ground connection pin to the short-type feedthrough capacitor, the ground connection pin can be connected to the shield member, and it is not necessary to connect the ground connection wiring to the shield member using a harness or the like. The number of points can be reduced, and the shield member can be easily grounded by a simple configuration.

Further, a plurality of terminals made of a U-shaped conductor are buried integrally in a portion of the case where the core is to be housed, and after the core is housed in the case, A printed circuit board for connection having a pattern for sequentially connecting the inner end and the outer end of the adjacent terminal is placed, and the terminal and the pattern of the printed circuit board can constitute a coil for winding the core a plurality of times. It has become.
In this case, a coil for winding the core can be formed by simply mounting the printed circuit board for connection and soldering the pattern and the inner or outer end of the terminal. Even when the current to be detected is a small current, the magnetic flux of the magnetic field acting on the Hall element is multiplied by the number of turns of the coil, so that the Hall element can reliably detect the magnetic flux.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail based on embodiments shown in the drawings. FIG. 1 shows an embodiment of the current detecting device according to the present invention. In FIG. 1, a current detection device 10 includes a case 11 having an open top surface having a penetrating portion 11a through which an electric wire through which a current to be detected flows is inserted,
A cover 12 capable of closing the upper surface of the case 11;
A ring-shaped gap core 13 housed in a case so as to surround one of the through portions 11a, and a hall element 14 disposed in the gap 13a of the core 13 (see FIG. 2).
Printed circuit board 15 on which a Hall element 14 is mounted and a power supply circuit for flowing a predetermined current to the Hall element and an amplifier circuit for amplifying the Hall voltage of the Hall element
And a shield member 16 and a shield cover 17 that can be disposed along the inner surfaces of the case 11 and the cover 12.

As shown in FIG. 3, the case 11 has a space around the through portion 11a for accommodating the ring-shaped core 13, and engages with an engagement portion of the core 13 described later. Rising portion 11 extending upward from the bottom surface to be formed
b and a low protruding portion 11c extending from below the rising portion 11b toward the through portion 11a.

As shown in FIG. 4, the core 13 has a gap 13a, and an engagement portion 13b made of an insulator integrally formed at the gap 13a. The core 13 is fixedly held in the case 11 in the longitudinal direction by engaging the engaging portion 13b with the rising portion 11b provided on the inner surface of the case 11. The gap 13a of the core 13 engages with the ridge 11c on the bottom surface of the case 11, so that the core 13 is fixedly held in the direction perpendicular to the longitudinal direction. Thus, the core 13 can be positioned at a predetermined position in the case 11 by the rising portions 11b and the ridges 11c, which are the engaging portions provided on the inner surface of the case.

Further, the core 13 has a projection 13c projecting upward on the upper surface of the engaging portion 13b. On the other hand,
As shown in FIG. 2, the printed circuit board 15 has a positioning hole 15a provided near the Hall element 14, and the positioning hole 15a The mounted Hall element 14 can be positioned at the center of the core 13 within the gap 13a.

As shown in FIG. 2, the shield member 16 is made of a substantially rectangular parallelepiped non-magnetic conductor, for example, copper with one surface opened along the inner surface of the case 11, and the shield cover 17 is made of the same material. Made of a nonmagnetic conductor. One edge of the shield cover 17 is connected to a side edge of the shield member 16. Then, the shield cover 17 is put on the shield member so as to close the open surface of the shield member 16, and a claw 16 a projecting upward from a side edge of the shield member 16 is bent on the shield cover 17,
By being soldered, it is defined as a closed rectangular parallelepiped.

At this time, as shown in FIG. 5, a window 16b for avoiding the penetration portion 11a provided in the shield member 16 is provided.
A rising portion 16c extending upward from a longitudinal edge of
A rising portion 17b extending downward from an edge in a direction perpendicular to the longitudinal direction of the window 17a for avoiding the penetrating portion 11a provided on the shield cover 17 is alternately formed with the penetrating portion 11a.
Is to be surrounded. Thereby, the shield member 16 and the shield cover 17 can shield the printed circuit board 15 including the core 13, the Hall element 14, and the circuit as shown in FIG. Therefore,
When a current to be detected flows as indicated by an arrow I in the drawing, a magnetic flux is generated in the core 13 as indicated by a thick arrow, and the magnetic flux passes through the gap 13a.

As shown in FIGS. 2 and 3, the case 11 has three connection pins 18 formed integrally with the case 11 so as to be drawn in from the outside.
6 and stands upright in the case 11, and each upper end thereof is connected to a through hole for connection provided on the printed circuit board 15 by soldering. At this time, as shown in FIG. 6A, each connection pin 18 passes through the shield member 16 via a feedthrough capacitor.

Here, in the case shown, the connection pins 18 on both sides are used.
a and 18c are respectively connected through the feedthrough capacitor 19,
An outer surface of the penetrating capacitor 19 is soldered to the shield member 16 while penetrating the shield member 16. Also, the center ground connection pin 18b
Penetrates the shield member 16 via the short type feedthrough capacitor 20, and the outer surface of the feedthrough capacitor 20 is soldered to the connection pin 18b and the shield member 16. Thereby, the shield member 16
Can be directly grounded by the ground connection pin 18b.

The current detecting device 10 according to the present invention is configured as described above. The shielding member 16 is inserted into the case 11 and the connection pins 18 are passed through the through capacitors 19 and 20, respectively. The shield cover 17 is left open with the soldering. From this state, the core 13 is inserted into the case 11 and the core 1
The third engaging portion 13b is engaged with the rising portion 11b of the case 11, and the gap 13a is engaged with the ridge portion 11c. Thereby, the core 13 is attached to a predetermined position in the case 11.

Subsequently, the positioning hole 1 of the printed board 15 is
5a is engaged with the protrusion 13c of the core 13, and the upper end of the connection pin 18 is fitted into the through hole. Thereafter, the mounting hole 15b of the printed circuit board 15 is aligned with the screw hole 11d provided at the upper end of the rising portion 11b of the case 11, and the printed circuit board 15 is positioned and mounted at a predetermined position by screwing. . Thereby, the Hall element 1 is located at the center of the gap 13a of the core 13.
4 can be accurately positioned.

Here, after the upper end of the connection pin 18 projecting upward from the through hole is soldered to the through hole, the shield cover 17 is bent as shown by an arrow in FIG. Align with the top edge of 16. The claws 16a of the shield member 16 are bent inward and soldered, so that the shield cover 17 can be fixedly held to the shield member 16 in a closed state.

Lastly, the upper end of the case 11 is closed with the cover 12, thereby completing the current detecting device 10.

According to the current detection device 10 assembled in this manner, the current flowing through the Hall element 14 is set to a predetermined value by the power supply circuit on the printed circuit board 15, and the through portion 11a of the case 11 is The magnetic flux passes through the gap 13a of the core 13 on the basis of the current passing from the core 13, and the Hall voltage of the Hall element 14 is uniquely determined according to the magnetic flux. Thus, the current can be detected by amplifying the Hall voltage by the amplifier circuit, outputting the Hall voltage to the outside, and appropriately processing the Hall voltage.

FIG. 7 shows a case of another embodiment of the current detecting device according to the present invention. In FIG. 7, the case 11 includes a plurality of terminals 21 arranged in a U-shape from below at a portion for accommodating the core 13 on a side opposite to the gap 13 a. Case 11
Each terminal 21 has an inner end 21a and an outer end 21b protruding upward. The terminals 21 located at both ends have the inner end or the outer end serving as the external connection terminals 22 and 23 in the case 11.
Has been pulled out to one side.

On the other hand, a connection printed circuit board 24 is mounted on the terminal 21. As shown in FIG. 8, one terminal 2 is provided on the lower surface of the connection printed circuit board 24.
An obliquely extending pattern 24a is formed so as to short-circuit the inner end 21a of the first terminal 21 and the outer end 21b of the adjacent terminal 21. When the terminal 21 is placed on the terminal 21, the terminals 21 are sequentially printed. By being connected via the pattern 24a of the substrate 24, a coil to be wound around the core 13 can be configured.

According to the current detecting device having such a configuration,
In the case of detecting a large current, as shown in FIG. 9, by passing the large current line 25 through the through portion 11a of the case 11, the current flowing through the large current line 25 can be detected by the Hall element.

When a small current is detected, a small current line is connected to the external connection terminals 22 and 23,
As shown in FIG. 9, since a small current flows through the coil 26 wound around the core in the case 11, the magnetic flux passing through the core gap can be doubled by the number of turns of the coil. Thus, the small current is more reliably detected by the Hall element.

When the coil 26 is wound externally, FIG.
As shown in FIG.
The workability can be improved by providing b and locking the winding start and winding end.

[0030]

As described above, according to the present invention, a shield member made of a substantially rectangular parallelepiped non-magnetic conductor having one open side along the inner surface of the case, and one edge of the shield member is formed on the side of the shield member. A shield cover connected to the edge is provided, and the shield cover is put on the shield member so as to close an open surface of the shield member, and a claw portion projecting upward from a side edge of the shield member is provided. Bent over the shield cover and soldered. Therefore, since the inside of the case is shielded, electromagnetic shielding can be easily performed with a simple configuration,
Costs can be reduced.

Further, the connection pins drawn into the case stand upright in the case after passing through the shield member via the feedthrough capacitor, and can be directly soldered to the connection through holes of the printed circuit board. Among the connection pins, a connection pin for grounding passes through the shield member and is connected to the shield member via a short-type feedthrough capacitor. Therefore, by soldering the ground connection pin to the short-type feedthrough capacitor, the ground connection pin can be connected to the shield member, and it is not necessary to connect the ground connection wiring to the shield member using a harness or the like. With a small number of points and a simple configuration, the ground connection of the shield member can be easily performed.

Further, a plurality of terminals made of a U-shaped conductor are buried integrally in a portion of the case where the core is to be housed, and after the core is housed in the case, A printed circuit board for connection having a pattern for sequentially connecting the inner end and the outer end of the adjacent terminal is placed, and the terminal and the pattern of the printed circuit board can constitute a coil for winding the core a plurality of times. It has become.
In this case, a coil for winding the core can be formed by simply mounting the printed circuit board for connection and soldering the pattern and the inner or outer end of the terminal. Even when the current to be detected is a small current, the magnetic flux of the magnetic field acting on the Hall element is multiplied by the number of turns of the coil, so that the Hall element can reliably detect the magnetic flux.

Thus, according to the present invention, assembling can be easily performed with a simple structure, the circuit portion can be easily electromagnetically shielded, and even if a small current is detected, the current can be reliably detected. The present invention provides an extremely excellent current detecting device which can be performed in the following manner.

[Brief description of the drawings]

FIG. 1 is an embodiment of a current detection device according to the present invention,
It is a schematic perspective view which shows the state which removed the cover.

FIG. 2 is an exploded perspective view showing a state where a core and a printed circuit board of the current detection device of FIG. 1 are removed.

3A and 3B show a case of the current detection device of FIG. 1, wherein FIG. 3A is a plan view, FIG. 3B is a sectional view taken along line AA, and FIG. 3C is a sectional view taken along line BB.

FIG. 4 shows a core of the current detection device of FIG. 1,
(A) is a plan view and (B) is a side view.

5A and 5B show a relationship between a shield member and a core of the current detection device of FIG. 1, wherein FIG. 5A is an exploded perspective view and FIG.

FIGS. 6A and 6B show the relationship between the connection pins upright in the case of FIG. 1, the shield member and the printed circuit board, FIG. 6A is a schematic perspective view, FIG. 6B is a partially enlarged view of the connection pins, and FIG. It is a partial enlarged view of a connection pin.

FIGS. 7A and 7B show a case of another embodiment of the current detection device according to the present invention, wherein FIG. 7A is a plan view and FIG.

FIG. 8 is a plan view of a printed circuit board for terminal connection used in the case of FIG. 7;

FIG. 9 is a schematic perspective view when detecting a small current in the case of FIG. 7;

FIG. 10 is a schematic perspective view showing a state in which a coil for detecting a small current is directly wound around a case.

FIG. 11 is a schematic diagram illustrating an example of a conventional current detection device.

FIG. 12 is a circuit diagram showing a configuration of the current detection device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Current detection device 11 Case 11a Penetration part 11b Rise part (engagement part provided in the case inner surface) 11c Ridge part (engagement part provided in the case inner surface) 12 Cover 12a Hook 12b Hook 13 Core 13a Gap 13b Insulation Engagement part 13c formed of body 13c Projection 14 Hall element 15 Printed circuit board 15a Positioning hole 15b Mounting hole 16 Shielding member 16a Claw 16b Window for avoiding penetrating part 16c Rising part 17 Shield cover 18 Connection pin 19 Penetrating capacitor 20 Short type penetrating capacitor 21 Pin 22 External connection terminal 23 External connection terminal 24 Connection printed board 25 High current line 26 Coil

Claims (3)

(57) [Claims] 1. A case having a penetrating portion through which an electric wire through which a current to be detected flows is inserted, a ring-shaped gapped core housed in the case so as to surround the penetrating portion of the case, and a gap between the cores. And a power supply circuit for supplying a predetermined current to the Hall element and an amplification circuit for amplifying a Hall voltage of the Hall element. The Hall element, the power supply circuit and the amplification circuit are mounted on a printed circuit board. In the current detecting device, a shield member made of a substantially rectangular parallelepiped non-magnetic conductor having one open side is provided along the inner surface of the case, and one edge thereof is connected to one side edge of the open surface of the shield member. are the arranged and a shield cover that is, the shield cover is put on the shield member so as to close the open face of the shield member, the shield of the open surface of the shield member Bar is consolidated
A claw portion projecting upward from another side edge other than the formed side edge is bent on a shield cover and soldered, so that the inside of the case is shielded. 2. A case having a penetrating portion through which an electric wire through which a current to be detected flows is inserted, a ring-shaped core with a gap housed in the case so as to surround the penetrating portion of the case, and a gap between the cores. And a power supply circuit for supplying a predetermined current to the Hall element and an amplification circuit for amplifying a Hall voltage of the Hall element. The Hall element, the power supply circuit and the amplification circuit are mounted on a printed circuit board. In the current detecting device, the connection pin drawn into the case is upright in the case after passing through the shield member through the feedthrough capacitor, and is directly soldered to the connection through hole of the printed circuit board. And the grounding connection pin passes through the shield member via the short-type feedthrough capacitor, and Characterized in that it is connected, the current detecting device. 3. A plurality of terminals made of a U-shaped conductor are buried integrally in a portion of the case where the core is to be accommodated, and after the core is accommodated in the case, A printed circuit board for connection having a pattern for sequentially connecting the inner end and the outer end of the adjacent terminal is placed, and the terminal and the pattern of the printed circuit board may constitute a coil for winding the core a plurality of times. The current detection device according to claim 1, wherein the current detection device is characterized in that: