JPH0754333B2 - Current detection unit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a current detection unit that detects a leakage of magnetic flux generated by a current flowing in a coil by a magnetic sensor.

[Background technology]

An example of a conventional current detection unit is shown in FIG. This is a coil unit 53 formed by winding a copper wire coil 52 around a core 51 of a ring-shaped magnetic material, and arranging a magnetic sensor 55 in a slit 54 that is formed by cutting a part of the core 51.
A magnetic field is generated in the core 51 by the current flowing through the core 52,
The intensity of the magnetic field of the magnetic flux leaked from the slit end face of 51 is detected by the magnetic sensor 55 to measure the amount of current flowing through the coil 52.

Moreover, what is shown in FIG. 7 is another conventional example. This forms a substantially annular core 56 with a rod-shaped magnetic body 56a and curved linear magnetic bodies 56b on both sides thereof, and a copper wire coil 57 is wound around the rod-shaped magnetic body 56a to form a coil unit 58, which is then curved. Both ends of the linear magnetic body 56b are opposed to the surface of the magnetic sensor 59, and the amount of current flowing through the coil 57 by detecting the magnetic field strength at the end surface of the linear magnetic body 56b by the magnetic sensor 59. Is to measure.

[Problems to be Solved by the Invention] However, in these conventional current detection sensors, since one coil is used for one magnetic sensor, a relatively large coil must be attached to the substrate. Therefore, it is not possible to disperse the coils in a gap portion between other components, which makes it difficult to design the arrangement of the current detection unit on the substrate.

Further, in the conventional current detection unit, since the closed magnetic circuit coil wound around the ring-shaped or substantially annular core is used, the outer shape becomes large due to the central space (hole of the coil) of the coil, This is an obstacle to downsizing the current detection unit. Further, the closed magnetic circuit coil has a structure in which winding work of the coil is difficult to perform, which causes a problem of high manufacturing cost.

The present invention has been made in view of the above technical background, and an object of the present invention is to provide a current detection unit that can easily design layout of coils and the like and has a simple structure and is inexpensive. In addition, it is to improve the detection efficiency of the magnetic detection unit.

[Means for Solving the Problems]

Therefore, in the current detection unit of the present invention, a plurality of open magnetic circuit coils are arranged, and the magnetic sensors are arranged between the coils so that the leakage magnetic flux emitted from these coils passes through the magnetic sensors. The yoke is arranged between the end portions on the side away from the magnetic sensor, and the convex portion provided on the yoke is brought into contact with the magnetic sensor.

[Action]

In the present invention, since a plurality of coils are arranged for one magnetic sensor and the magnetic flux of each coil passes through the magnetic sensor, the same current is applied to each coil and the magnetic sensor An electric current can be passed in a direction in which the magnetic fields of the coils reinforce each other at the position. Therefore, if the same sensitivity is obtained, each coil can be made smaller than the case where only one coil is used as in the conventional example, and this plurality of small coils can be distributed and arranged on the substrate or the like. Also, the layout design of the current detection unit on the substrate or the like becomes easy, and high-density mounting of the substrate can be supported.

Moreover, since the yoke is arranged between the ends of the respective coils which are separated from the magnetic sensor, it is possible to form a closed magnetic path by the coils and the yoke on the side opposite to the magnetic sensor, and the side opposite to the magnetic sensor. The leakage of the magnetic flux to the outside of the unit can be reduced and the magnetic flux can be concentrated on the magnetic sensor, and the detection efficiency can be improved.

Furthermore, the magnetic sensor can be easily positioned by bringing the protrusion provided on the yoke into contact with the magnetic sensor.
The magnetic sensor can be placed in the most sensitive position.

Further, since the open magnetic path coil is used, the current detection unit can be downsized, the winding work of the coil can be simplified, and the manufacturing cost of the current detection unit can be reduced. .

〔Example〕

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

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

The chip coil 4 is formed by winding a copper wire coil 2 around an outer periphery of a core 5 made of a magnetic material such as ferrite. The core 5 is provided with flanges 7 on both ends of a columnar coil winding portion 6, and the coil 2 is wound around the coil winding portion 6. Since this chip coil 4 has an open magnetic path structure, it is only necessary to wind the coil 2 around the straight coil winding portion 6 at the time of manufacturing the chip coil 4, and the winding work of the coil 2 can be performed easily, and the manufacturing cost can be reduced. Can be cheaper. Further, the size can be reduced as compared with a coil unit having a closed magnetic circuit structure such as a ring. 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 conversion element such as a Hall element or a magnetoresistive element, and a lead terminal 9 extends from the magnetic sensing section 8.

In addition, the substrate 1 that constitutes the current detection unit 10 is
A sensor housing hole 11 for housing the magnetic sensor 3 is opened in a part of the current detection unit which is a part of a board for mounting other electronic circuits and the like. Also,
This substrate 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 the lead terminals 9 of the magnetic sensor 3 are provided on the lower surface. A wiring pattern (not shown) for connecting the wirings is provided.

Then, as shown in FIG. 1, the magnetically sensitive portion 8 of the vertically oriented magnetic sensor 3 is inserted into the sensor housing hole 11 from the lower surface of the substrate 1, and the lead terminals 9 of the magnetic sensor 3 are connected to the substrate 1 by the solder 12. It is soldered to the lower surface wiring pattern. Board 1
Chip coils 4, 4 are vertically placed on the upper surface of the chip coil 4 with a magnetically sensitive portion 8 interposed therebetween, and electrodes of the chip coils 4, 4 are soldered to the upper surface wiring pattern by solder 13. further,
A yoke 15 made of a magnetic material such as ferrite is laid between the upper end surfaces of the chip coils 4, 4, and the ends of the yoke 15 are fixed to the end surfaces of the chip coils 4, 4 with an adhesive agent 14 or the like. York 15
A convex portion 16 is provided on the lower surface of the magnetic sensor 3, and the upper surface of the magnetic sensor 3 is in contact with the lower surface of the convex portion 16. In this way, the magnetic sensor 3 is positioned relative to the chip coils 4, 4 by the convex portion 16 and is positioned so as to obtain maximum sensitivity. In addition, each flange 7,7 of the chip coil 4,4
Is also brought into contact with the side surface of the convex portion 16, so that the distance between the flanges 7 and 7 is kept constant.
Are positioned relative to each other. If the distance between the flanges 7, 7 of the chip coils 4, 4 varies, the sensor sensitivity also varies.
A constant sensitivity can be obtained by keeping the distance between the four constant. 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 coils 4, 4 can be used.
Can be mounted at a predetermined position with high accuracy by an automatic machine or can be positioned also with a wiring pattern. Therefore, the chip coils 4, 4 and the magnetic sensor 3 can be positioned with high accuracy, and stable detection accuracy can be obtained.

The two coils 2, 2 are connected in series or in parallel, for example, by the wiring pattern of the substrate 1 so that current flows through both coils 2 and 2 at the same time to generate magnetic flux, and the magnetic sensor 3 senses. They are connected in such a direction that the magnetic flux density passing through the magnetic portion 8 increases. Therefore, in order to obtain the same sensitivity, each coil 2,2 can be made smaller than the case of only one coil, and these two small coils 2,2 can be dispersedly arranged on the substrate 1, and other components The coils can be arranged in a gap between them, which facilitates the layout design 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. The leakage of magnetic flux can be reduced, magnetic energy can be concentrated on the magnetic sensor 3, and the detection efficiency can be improved. Further, since the convex portion 16 formed of the magnetic material is disposed between the upper flanges 7 and 7, the magnetic flux leaking from the flanges 7 and 7 can be picked up in the convex portion 16 and the chip coil 4,4 upper flange
It is possible to reduce the leakage magnetic flux leaking into the air from 7, 7 and further improve the sensitivity of the current detection unit 10.

It should be noted that it is also possible to detect two currents of different systems using the current detection unit 10. In this case,
The electrodes are connected so that currents of different circuits flow through the two coils 2, 2. Then, when a current flows through any of the coils 2, a magnetic flux is generated in the core 5, and the magnetic flux leaking from the lower flange 7 is detected by the magnetic sensor 3, and the magnetic sensor 3 determines the strength of this magnetic field. By detecting, the amount of current flowing through the coil 2 is measured. In this case, the magnetic sensor 3 can detect when any current flows in any of the coils 2, so that one magnetic sensor 3 can detect two currents.
Can be shared by the two coils 2. When the coil 2 has the core 5, even when only one coil 2 is excited, the excited coil 2, the yoke 15 and the other core 5 form a closed magnetic circuit.

FIG. 2 shows a second embodiment of the present invention (the same parts as those in the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The same applies to the following embodiments). The magnetic sensor 3 is surface-mounted.

FIG. 3 shows a magnetic sensor 3 according to a third embodiment of the present invention.
The lead terminals 9 are inserted into the substrate 1 and the lead terminals 9 are soldered to the lower surface wiring pattern 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 and 4 are arranged in parallel on the substrate 1 and the end faces of the chip coils 4 and 4 are arranged on the side opposite to the magnetic sensor 3. In York 15
Is provided.

FIG. 5 shows a fifth embodiment of the present invention, one flange 7a
Has a long width and the other flange 7b has a short width, and a pair of chip coils 4, 4 are laid side by side on the substrate 1 in parallel, and the magnetic sensor 3 is arranged between the wide flanges 7a, A yoke 15 is arranged between the flanges 7b having a short width.

The embodiment of the present invention is not limited to the above embodiment,
Various other methods are possible. For example, in the above embodiment,
Although both use two chip coils, three or more chip coils may be used. Further, not only the chip coil containing the core but also the coil alone may be used.

〔The invention's effect〕

According to the present invention, relatively small coils can be dispersedly arranged on a substrate or the like, the degree of freedom of arrangement on the substrate or the like can be increased, and the layout design can be facilitated, and high-density mounting of the substrate can be facilitated. Become. Moreover, since the yoke is arranged between the ends of the coil on the side opposite to the magnetic sensor, a closed magnetic path is formed by the coil and the yoke on the side opposite to the magnetic sensor, and the magnetic flux to the outside of the unit on the side opposite to the magnetic sensor. The leakage can be reduced to concentrate the magnetic flux on the magnetic sensor, and the detection efficiency can be improved. Further, the magnetic sensor can be positioned so as to obtain the maximum sensitivity by bringing the magnetic sensor into contact with the convex portion provided on the yoke. Further, since the open magnetic circuit coil is used, there is no useless space unlike the closed magnetic circuit coil, and the current detection unit can be further downsized. Further, by using the open magnetic circuit coil, the winding work of the coil can be simplified, and the manufacturing cost of the current detection unit can be reduced.

[Brief description of drawings]

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 present invention, and FIG. 3 is a front view showing a third embodiment of the present invention. FIG. 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, FIG. 6 is a perspective view of a conventional example, and FIG. It is a perspective view of a prior art example. 2 ... Coil, 3 ... Magnetic sensor 15 ... Yoke 16 ... Convex part

Claims (1)

[Claims] 1. A plurality of open magnetic circuit coils are arranged, and a magnetic sensor is arranged between the coils so that a leakage magnetic flux emitted from these coils passes through the magnetic sensors, and is separated from the magnetic sensors of these coils. A current detecting unit, characterized in that a yoke is disposed between the end portions on the opposite side, and a convex portion provided on the yoke is brought into contact with the magnetic sensor.