JPH05126861A - Current sensor - Google Patents

Abstract

(57) [Summary] [Structure] A ferromagnetic core 4 having a part of the magnetic path opened, a spool 6 wound around one side of the core 4 and wound with a coil 3, and a core 4 near the opening. The Hall element 2 to be arranged is mounted on the substrate 1. A detection circuit for amplifying and outputting the output of the hall element 2 is also formed on the substrate 1. On the other hand, the substrate 1 has a recess 5 formed on the back surface thereof to reduce the core gap, and the tip of the core 4 disposed on the lower surface of the substrate 1 is fitted and fixed therein. [Effect] The positioning accuracy of the core can be improved by increasing the magnetic efficiency of the magnetic circuit to improve the current detection sensitivity, and by adopting a fitting structure for the substrate recess and the core tip.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current sensor, and more particularly to a current sensor for determining the strength of a current flowing through a coil.

[0002]

2. Description of the Related Art Conventionally, a current sensor of this type is constructed by mounting a spool around which a coil is wound on a core, mounting the spool together with a Hall element on a substrate, and forming a detection circuit.

FIGS. 2A and 2B are a front view and a side view of a conventional current sensor, respectively. Figure 2
As shown in (a) and (b), the conventional current sensor has a flat magnetic circuit system including a spool 6 around which the coil 3 is wound, a core 4A penetrating the spool 6, and a Hall element 2. A detection circuit (not shown) that is mounted on the substrate 1A and amplifies and outputs the output of the Hall element 2 is formed on the substrate 1A. Moreover, the Hall element 2 is mounted on the substrate 1A near the opening of the core 4A.

[0004]

The conventional current sensor described above forms a magnetic circuit by sandwiching a flat ceramic substrate between parallel portions of the core. For this reason, the core gap must be widened by the thickness of the substrate. Therefore, the magnetic efficiency of the magnetic circuit is lowered and the current detection sensitivity is lowered, so that there is a drawback that a large coil must be wound. In addition, if the thickness of the substrate is made thin to improve the magnetic efficiency, the strength of the substrate will be reduced, and the substrate will be damaged during assembly. Then, there is a drawback that the withstand voltage between the primary and secondary circuits of the current sensor decreases. Further, when the flat substrate is sandwiched between the cores to position the cores, it is difficult to accurately determine the positions of the cores and the Hall elements.

An object of the present invention is to provide a current sensor capable of improving such current detection sensitivity and core positioning accuracy.

[0006]

SUMMARY OF THE INVENTION A current sensor according to the present invention comprises a ferromagnetic core in which a part of a magnetic path is opened, a spool wound around one of the ferromagnetic cores and wound with a coil, and A Hall element disposed near the opening of the core is mounted on the substrate, and a detection circuit for amplifying and outputting the output of the Hall element is formed on the substrate to identify the strength of the current flowing through the coil. In the current sensor described above, a recess is provided on the back surface of the substrate, into which the other end of the core arranged on the bottom surface of the substrate is fitted.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

1A and 1B are a front view and a side view of a current sensor showing an embodiment of the present invention. As shown in FIGS. 1A and 1B, in this embodiment, a ferromagnetic core 4 having an opening in a part of a magnetic path, and a spool 6 around one of the cores 4 and around which a coil 3 is wound. And core 4
The Hall element 2 arranged in the vicinity of the opening is mounted on a flat substrate 1 made of ceramic or the like. A detection circuit (not shown) that amplifies and outputs the output of the Hall element 2 is formed on the surface of the substrate 1. Coil 3 by this Hall element 2
Identify the strength of the current flowing through. In this embodiment, a substrate concave portion 5 is formed on the back surface of the substrate 1, and the other tip portion of the core 4 arranged on the lower surface of the substrate 1 is fitted therein.

As described above, in this embodiment, the opening can be sandwiched by fitting the Hall element 2 on the substrate 1 and the lower end of the core 4 incorporating the coil 3 into the recess 5. Therefore, the thickness of the substrate 1 can be maintained, and a large coil is not required, and the current detection sensitivity and the core positioning accuracy can be improved.

[0010]

As described above, in the current sensor of the present invention, by forming the concave portion on the back surface of the substrate, the gap distance between the cores can be shortened without lowering the dielectric strength voltage, so that the magnetic efficiency of the magnetic circuit is improved. This has the effect of improving the current detection sensitivity. Further, the present invention has the effect of improving the positioning accuracy of the Hall element and the core by fitting the recess of the substrate and the core.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a front surface and a side surface of a current sensor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a front surface and a side surface of a current sensor showing an example of the related art.

[Explanation of symbols]

 1 substrate 2 hall element 3 coil 4 ferromagnetic core 5 substrate recess 6 spool

Claims (1)

[Claims] 1. A ferromagnetic core having an opening in a part of a magnetic path,
Detecting a spool in which one side of the ferromagnetic core is wound and a coil is wound, and a hall element arranged near the opening of the core is mounted on a substrate, and the output of the hall element is amplified and output. In a current sensor for identifying the strength of current flowing through the coil by forming a circuit on the substrate, the other end of the core arranged on the lower surface of the substrate is fitted to the back surface of the substrate. A current sensor characterized by having a recess.