JPH02195268A - Unit for sensing current - Google Patents

Abstract

PURPOSE:To improve sensing efficiency of a unit for detecting magnetism by providing a yoke between terminals on a side separate from a magnetic sensor of a plurality of open magnetic path coils. CONSTITUTION:A plurality of open magnetic path coils 2 are provided on a substrate 1, while a magnetic sensor 3 is provided between the coils 2 so that leakage flux from the coils 2 is passed through the sensor 3. Between terminals on a side of the coils 2 separated from the sensor 3 a yoke 15 is provided. This enables a close magnetic path to be formed by the respective coils 2 and the yoke 15 on an opposite side to the sensor 3 so that leakage flux to outside of the unit on the opposite side to the sensor 3 is reduced to be concentrated on the sensor 3 thereby improving sensing efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a current detection unit that uses a magnetic sensor to detect leakage of magnetic flux generated by a current flowing through a coil.

[Background technology]

An example of a conventional current detection unit is shown in FIG. A coil unit 53 is formed by winding a copper wire coil 52 around a ring-shaped magnetic core 51, and a magnetic sensor 55 is placed in a slit 54 made by cutting out a part of the core 51. A magnetic field is generated in the core 51 by the flowing current, and the amount of current flowing through the coil 52 is measured by detecting the strength of the magnetic field of the magnetic flux leaking from the slit end face of the core 51 with a magnetic sensor 55.

Moreover, what is shown in FIG. 14 is another conventional example. This consists of a rod-shaped magnetic body 56a and curved linear magnetic bodies 56 on both sides of the rod-shaped magnetic body 56a.
b forms a substantially annular core 56, and this rod-shaped magnetic body 5
A coil unit 58 is formed by winding a coil 57 of copper wire around 6a, and both ends of a curved linear magnetic body 56b are opposed to the surface of a magnetic sensor 59.
The amount of current flowing through the coil 57 is measured by detecting the strength of the magnetic field at the end face of the coil 6b using a magnetic sensor 59.

[Problem to be solved by the invention]

However, these conventional current detection sensors use one coil for - magnetic sensors, so a relatively large coil must be attached to the board, and the coil must be mounted between other components. It was difficult to design the placement of the current detection units on the board because it was not possible to distribute them in spaces such as gaps.

Furthermore, since conventional current detection units use a closed magnetic circuit coil wound around a ring-shaped or approximately annular core, the outer diameter becomes large due to the space in the center of the coil (hole in the core). This is an obstacle to downsizing the current detection unit. Further, the closed magnetic circuit coil has a structure that makes it difficult to wind the coil, resulting in a problem of high manufacturing costs.

The present invention has been made in view of the above-mentioned technical background, and its purpose is to provide a current detection unit that can easily design the arrangement of coils, etc., has a simple structure, and is inexpensive. In addition, the object is to improve the detection efficiency of the magnetic detection unit.

[Means to solve the problem]

Therefore, in the current detection unit of the present invention, a plurality of open magnetic path coils are arranged, and a magnetic sensor is arranged between the coils so that the leakage magnetic flux from these coils passes through the magnetic sensor. A yoke is disposed between the ends of the magnetic sensor on the side away from the magnetic sensor.

[Effect]

In the present invention, a plurality of coils are arranged for - magnetic sensors, and the magnetic flux of each coil passes through the magnetic sensor, so that the same current is passed through each coil and the magnetic sensor Current can be passed in the direction where the magnetic fields from each coil strengthen each other at the position. Therefore, if the same sensitivity is to be obtained, each coil can be made smaller than when using only one coil as in the conventional example, and multiple small coils can be distributed and arranged on a board, etc. , it becomes easy to design the layout of the current detection unit on the board, etc., and it is possible to support high-density mounting of the board.

Moreover, since a yoke is arranged between the ends of each coil on the side away from the magnetic sensor, a closed magnetic path can be formed by each coil and yoke on the side opposite to the magnetic sensor, and the opposite end of the magnetic sensor It is possible to reduce the leakage of magnetic flux to the outside of the unit at the side, concentrate the magnetic flux on the magnetic sensor, and improve detection efficiency.

Furthermore, since an open magnetic path coil is used, the current detection unit can be made smaller, and the coil winding work can be simplified, reducing the manufacturing cost of the current detection unit. .

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

What is shown in FIGS. 1 and 2 is a first embodiment of the present invention, in which two chip coils 4, 4 are arranged vertically on the upper surface of a substrate 1.

The chip coil 4 has a coil 2 of copper wire wound around a core 5 made of a magnetic material such as ferrite. The koala has flanges 7 provided at both ends of a columnar coil winding part 6, and the coil 2 is wound around the coil winding part 6. Since this chip coil 4 has an open magnetic path structure, when manufacturing the chip coil 4, it is only necessary to wind the coil 2 around the straight coil winding part 6, which makes the winding work of the coil 2 easy and reduces the manufacturing cost. can be made inexpensive. Further, it can be made smaller than a coil unit having a closed magnetic circuit structure such as a ring shape. Since the chip coil 4 is surface mounted on the substrate 1 such as a printed wiring board, the flange 7 is provided with two electrodes (not shown), and both ends of the coil 2 are electrically connected to these electrodes. It is connected to the.

The magnetic sensor 3 uses a magnetoelectric transducer such as a Hall element or a magnetoresistive element, and a lead terminal 9 extends from a magnetic sensing part 8 .

Further, the board 1 for configuring the current detection unit 10 is a part of a board for mounting other electronic circuits, etc.
A sensor storage hole 11 for housing the magnetic sensor 3 is opened in the current detection unit component. In addition, this board 1 is a double-sided printed wiring board,
A wiring pattern (not shown) for connecting the electrodes of the chip coil 4 is provided on the upper surface of the substrate 1, and a wiring pattern (not shown) for connecting the lead terminal 9 of the magnetic sensor 3 is provided on the lower surface. It is provided.

However, as shown in FIG.
Then, the lead terminal 9 of the magnetic sensor 3 is soldered to the wiring pattern on the lower surface of the substrate 1 using solder 12.

On the upper surface of the substrate 1, a chip coil 4.
4 are placed vertically, and the electrodes of each chip coil 4, 4 are soldered to the upper surface wiring pattern using solder 13. Furthermore, a yoke 15 made of a magnetic material such as ferrite is installed between the upper end surfaces of both chip coils 4, 4, and an adhesive 1
4 or the like, the ends of the yoke 15 are fixed to the end surfaces of the chip coils 4, 4. In addition, since the magnetic sensor 3 is housed in the sensor housing hole 11, the sensor housing hole 11 can be used as a positioning means for the magnetic sensor 3, and the chip coil 4.4 can also be precisely positioned at a predetermined position by an automatic machine or the like. The chip coil 4.4 and the magnetic sensor 3 can be positioned with respect to each other with high accuracy, and stable detection accuracy can be obtained.

The two coils 2.2 are connected, for example, in series or parallel, depending on the wiring pattern on the board 1, so that current flows through both coils 2.2 at the same time and generate magnetic flux together, and the sensitivity of the magnetic sensor 3 They are connected in such a direction that the magnetic flux density passing through the magnetic part 8 increases. Therefore, in order to obtain the same sensitivity, each coil 2, 2 can be made smaller than in the case of only one coil, and these two small coils 2
．． The coils 2.2 can be distributed and arranged on the substrate 1, and can be arranged in gaps between other parts, making it easy to design the arrangement of the coils 2.2. Moreover, since the yoke 15 is disposed between the chip coils 4 and 4, a closed magnetic path is formed on the opposite side of the magnetic sensor 3 as shown in FIG. Leakage of magnetic flux can be reduced, magnetic energy can be concentrated on the magnetic sensor 3, and detection efficiency can be improved.

Note that it is also possible to detect two currents from different systems using the current detection unit 10. In this case, the electrodes are connected in such a way that the current of the resulting circuit flows through the two coils 2.2. When current flows through one of the coils 2, magnetic flux is generated within the corer, and the magnetic flux leaking from the lower flange 7 is detected by the magnetic sensor 3, which detects the strength of this magnetic field. By doing so, the amount of current flowing through the coil 2 is measured.

In this case, the magnetic sensor 3 can detect when a current flows through any of the coils 2, so one magnetic sensor 3 can detect two currents, and the magnetic sensor 3 can be connected to two coils 2. can be shared.

In addition, when the coil 2 has the core 5, even if only one coil 2 is excited, a closed magnetic path is formed by the excited coil 2, the yoke 15, and the other corer.

FIG. 2 shows a second embodiment of the present invention (portions similar to those in the embodiment of FIG. The magnetic sensor 3 is surface mounted.

FIG. 3 shows a third embodiment of the present invention, in which a magnetic sensor 3
The lead terminals 9 are inserted through the substrate 1, and the lead terminals 9 are soldered to the wiring pattern on the lower surface of the substrate 1 on the lower surface side.

FIG. 4 shows a fourth embodiment of the present invention, in which a pair of chip coils 4, 4 are arranged horizontally and parallel on a substrate 1, and between the end faces of the chip coils 4, 4 on the opposite side from the magnetic sensor 3. A yoke 15 is disposed on the yoke 15.

5, 6 and 7 respectively show a fifth embodiment, a sixth embodiment and a seventh embodiment of the present invention, in which one flange 7a is long and the other flange 7b is wide. A pair of short chip coils 4.4 are arranged horizontally on the substrate 1 in parallel. Furthermore, in the embodiment shown in FIG. 5, the magnetic sensor 3 is arranged between the wide flanges 7a, and the yoke 15 is arranged between the short flange b. 6th
In the illustrated embodiment, the magnetic sensor 3 is placed between the narrow flanges 7b, and the yoke 1 is placed outside between the wide flanges 7a.
5 is placed. In the embodiment shown in FIG. 7, the magnetic sensor 3 is arranged between the narrow flanges 7b, and the yoke 15 is arranged inside between the wide flanges 7a.

What is shown in FIGS. 8(a) and 8(b) is an eighth embodiment of the present invention, in which a pair of chip coils 4.4 are arranged vertically on a substrate 1, and between an upper flange 7.7. A magnetically sensitive portion 8 is arranged, and a sheet-like yoke 15 is arranged between both sides of the lower flange 7.7 on the upper surface of the substrate 1.

What is shown in FIG. 9 is a ninth embodiment of the present invention, in which the substrate 1
A pair of chip coils 4.4 are arranged coaxially on the top, a magnetic sensor 3 is arranged between both chip coils 4, 4, and a U-shaped yoke 1 is placed across the top of the chip coils 4.4.
5 is arranged.

FIG. 10 shows a disciple embodiment of the present invention, in which a pair of chip coils 4, 4 are placed horizontally and coaxially on a substrate 1, and a magnetic sensor 3 is placed between both chip coils 4, 4. A yoke 15 is disposed between both sides (or only one side) of the outer wide flange 7a.

FIG. 11 shows a disciple-embodiment of the present invention, in which a magnetic sensing part 8 of a magnetic sensor 3 is placed in a sensor storage hole 11 opened in a substrate 1.
The chip coils 4.4 are arranged vertically on the upper and lower surfaces of the substrate 1 at the top and bottom of the sensor housing hole 11, respectively, and the upper flange 7 of the upper chip coil 4 and the lower part of the lower chip coil 4 are arranged vertically. A U-shaped yoke 15 is disposed between the flange 7 and the flange 7.

FIG. 12 shows a second embodiment of the present invention, in which a magnetic sensing part 8 of a magnetic sensor 3 is placed in a sensor housing hole 11 opened in a substrate 1.
The chip coils 4.4 are placed horizontally on the upper and lower surfaces of the substrate 1 in the vicinity of the sensor storage hole 11, and the magnetic sensor 3 is placed on the 7 flanges of one of both chip coils 4, and the magnetic sensor 3 is placed on the 7 flanges of one of the chip coils 4, and A U-shaped yoke 15 is disposed between the flanges 7.

Note that the embodiments of the present invention are not limited to the above embodiments,
Various other possibilities are also possible. For example, in the above embodiment,
In both cases, two chip coils are used, but three or more chip coils may be used, and not only a chip coil with a core but also a coil alone may be used.

〔Effect of the invention〕

According to the present invention, relatively small coils can be distributed and arranged on a board, etc., increasing the degree of freedom of arrangement on the board, etc., making layout design easier, and high-density mounting of the board is facilitated. Become. Furthermore, since the yoke is placed between the ends of the coil on the side opposite to the magnetic sensor, a closed magnetic path is formed by the coil and yoke on the side opposite to the magnetic sensor, and the magnetic flux is directed to the outside of the unit on the side opposite to the magnetic sensor. It is possible to reduce leakage and concentrate magnetic flux on the magnetic sensor, improving detection efficiency.

Furthermore, since an open magnetic path coil is used, there is no wasted space unlike a closed magnetic path coil, and the current detection unit can be further miniaturized. Further, by using an oven magnetic path coil, the coil winding work can be simplified, and the manufacturing cost of the current detection unit can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing a first embodiment of the present invention, Fig. 2 is a front view showing a second embodiment of the invention, and Fig. 3 is a front view showing a third embodiment of the invention. 4 is a plan view showing a fourth embodiment of the present invention, FIG. 5 is a plan view showing a fifth embodiment of the present invention, and FIG. 6 is a plan view showing a sixth embodiment of the present invention. FIG. 7 is a plan view showing a seventh embodiment of the present invention, and FIG.
a) and (b) are a front view and a plan view showing the eighth embodiment of the present invention, FIG. 9 is a front view showing the ninth embodiment of the present invention, and FIG.
11 is a partially cutaway front view showing the Disciple embodiment of the present invention, and FIG. 12 is a partially broken front view showing the Disciple 2 embodiment of the present invention. A front view, FIG. 13 is a perspective view of a conventional example, and FIG. 14 is a perspective view of another conventional example. 2... Coil 3... Magnetic sensor 5.
...Yoke Figure 1! ; Fig. Fig. Fig. 11 Fig. 12 Fig. Fig. 1 b

Claims (1)

[Claims] (1) A plurality of open magnetic path coils are arranged, a magnetic sensor is arranged between the coils so that the leakage magnetic flux from these coils passes through the magnetic sensor, and the side of these coils remote from the magnetic sensor is A current detection unit characterized by having a yoke arranged between the ends of the unit.