JP2002243768A - Electric current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in an electric current detector 90 of conventional structure that it has no flexibility in figuration, because, once the insertion direction of a current path 97 is fixed, the direction of a core 91, the direction of a gap 91a, the direction of an magnetoelectric transfer element 94, and the direction of a printed circuit board 96 are fixed, and it becomes impossible to make thinner the current detector 90 in a desired direction. SOLUTION: In this electric current detector 1, an upper surface of a case is opened, a core having a gap in its one arm on the shorter arm sides is disposed so that the shorter arm sides are substantially perpendicular to the upper surface of the case, an magnetoelectric transfer element is disposed in a cutout or a hole provided in a part of a board, the board is mounted with circuit components and disposed in the case and in a direction substantially parallel to the upper surface of the case, and a bus bar is put through a hollow part of the core. Its assembling work is thereby simplified, the width of the current detector 1 can be reduced, and thus its miniaturization is made possible.

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, for example, a load current of a battery of an automobile without contacting an electric circuit, and more particularly, to a current detecting device formed of a ferromagnetic material surrounding the electric circuit. And a Hall element installed in a gap provided in the core.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a conventional current detecting device 90 of this type. The current detecting device 90 is formed of a ferrite or silicon steel plate so as to have a substantially rectangular shape and a hollow portion 91b. 91 provided with a gap portion 91a in the core 91
Is placed in a case 92 made of thermoplastic resin.
The opening 92a and the hollow portion 91b are attached so as to coincide with each other. The case 92 is integrally formed with an input / output terminal 93a built-in connector 93.

[0003] A magneto-electric conversion element 94 such as a Hall element for detecting magnetic flux is provided together with a circuit 95 for amplifying the output of the magneto-electric conversion element 94 and a land hole 96a for terminal connection.
The leads are mounted upright on a printed circuit board 96 provided with the printed circuit board 96, and the printed circuit board 96 is fixed to the case 92 by screwing or the like.
1a. Then, the land holes 96a of the printed circuit board 96 and the terminals 93a are connected by soldering or the like.

[0004] Thereafter, in order to cancel the variation in sensitivity of the magnetoelectric conversion element 94 itself, the variation in unbalanced voltage, and the variation in offset voltage of the operational amplifier used in the amplifier circuit, it is mounted on a printed circuit board 96. The constant of the resistor of the circuit 95 is adjusted. Further, the gap portion 91a of the core 91 has a certain tolerance, and the sensitivity depending on the mounting angle of the magneto-electric conversion element 94 also changes. Need to adjust. This adjustment includes adjustment by the volume of the circuit 95 and adjustment by laser trimming.

After this adjustment, the case 92 is filled with a molding material to secure the core 91 and the printed circuit board 96, and to provide waterproofing in place of the lid. Ensure vibration.

The current detecting device 90 configured as described above is
A current flowing through the electric circuit 97 can be measured by penetrating an electric circuit 97 such as a bus bar into the opening 92a of the case 92 passing through the hollow portion 91b of the core 91 and attaching an external device to the terminal 93a of the connector 93. Things.

[0007]

However, in the current detecting device 90 having the above-mentioned conventional configuration, the electric circuit 97
Is determined, the orientation of the core 91 and the gap 91a are determined.
Direction, the direction of the magneto-electric conversion element 94, the printed circuit board 9
6, the direction of the current detecting device 90 cannot be reduced in the desired direction, and the shape of the current detecting device 90 is inflexible.

Although the magneto-electric conversion element 94 is of a lead type for structural reasons, other components can be automatically mounted by surface mounting components, whereas only the magneto-electric conversion element 94 is used. Due to the manual mounting, workability and productivity have been deteriorated.

[0009]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, there is provided a core fixed in a case in which a gap portion is provided on one side of a substantially rectangular shape and fixed in a case. In a current detection device that arranges a magnetoelectric conversion element in a gap portion and detects a change in magnetic flux generated in the core as a current, the case has an open upper surface, the core has the gap portion on one side, Arranged so that one side is substantially perpendicular to the upper surface of the case, the magnetoelectric conversion element is arranged in a notch or hole provided in a part of the substrate,
The substrate has a circuit component mounted thereon and is arranged in the case substantially parallel to the upper surface of the case, and a bus bar is inserted through a hollow portion of the core to provide a current detection device. This solves the problem.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail based on an embodiment shown in the drawings. FIGS. 1 to 5 show an embodiment of the present invention. In the drawings, the reference numeral 1 denotes a current detecting device according to the present invention. The current detecting device 1 includes a case 2 having at least an open upper surface, a core 3 formed in a substantially rectangular shape from a ferrite or a silicon steel plate, a magnetoelectric conversion element 5 such as a Hall element mounted on a substrate 4, It comprises a circuit element 6 for adjusting the magnetoelectric conversion element 5 mounted on the substrate 4 and amplifying the output, and a bus bar 7 serving as an electric path.

First, the case 2 is formed in a box shape with resin or the like, and its upper surface is open. A connection terminal 2a for external output is integrally formed on the side wall of the case 2.

Next, the core 3 is made of ferrite, silicon steel plate or the like as in the prior art, and is formed in a rectangular substantially rectangular shape. On one side of the short side 3c of the core 3, a gap 3a in which the magnetoelectric conversion element 5 is arranged is formed.

FIG. 5 shows that the magnetoelectric conversion element 5 is mounted on the substrate 4.
The magneto-electric conversion element 5 is provided with a notch 4a at an end of the substrate 4, and leads 5a of the magneto-electric conversion element 5 are bridged between the substrates at the end of the notch 4a. And the main body 5b of the magnetoelectric conversion element 5 is connected to the notch 4
a. And
An adjustment circuit for the magnetoelectric conversion element 5 and an amplification circuit 6 for output are mounted on the substrate 4, and terminals 4
c is connected to the connection terminal 2a of the case 2. The notch 4a provided in the substrate 4 may be a hole 4b.

At this time, the magneto-electric conversion element 5 is of a surface-mount type, and this surface-mount type
In this case, the lead 5a protrudes from the vicinity of the bottom surface of the main body 5b, and the main body 5b is generally configured to protrude upward. Such a magnetoelectric conversion element 5 is attached downward so that the protruding main body 5b side is located in the notch 4a provided in the substrate 4. That is, it is provided in a direction opposite to the vertical direction in which it is generally placed. According to this configuration, the interval between the gap portions 3a provided in the core 3 may be set to be slightly wider than the thickness of the magnetoelectric conversion element 5, so that the magnetic flux collection effect is not reduced and the noise of disturbance noise is reduced. It can be less susceptible.

Next, the bus bar 7 is connected to an electric path for detecting a current, and is made of a material having good conductivity such as copper. The bus bar 7 is inserted through the hollow portion 3b of the core 3 and is arranged. An end of the bus bar 7 protrudes from the case 2 and serves as a terminal 7a for connection of an electric circuit.

Then, assembling of the current detecting device 1 is as follows.
First, the bus bar 7 is passed through the hollow portion 3b of the core 3 and is disposed at a predetermined position of the case 2. A predetermined guide is formed on the case 2, and the core 3 is connected to the short side 3c.
However, it is housed in the case 2 so that the upper side of the case 2 is perpendicular to the upper surface, that is, the long side 3d is substantially parallel to the upper surface.
Further, the bus bar 7 is formed in a concave shape so that an end thereof is located substantially in the same plane as the upper surface of the case, and is fixed along a guide of the case 2.

Next, the substrate 4 is arranged so that the magnetoelectric conversion element 5 enters the gap 3a of the core 3 housed in the case 2. Then, the terminals 4c provided on the substrate 4 and the connection terminals 2a of the case 2 are soldered.
Thereafter, the adjustment circuit by the circuit element 6 mounted on the substrate 4 is adjusted. This is adjusted by, for example, irradiating a laser to the sensitivity and offset trimming resistors while supplying a prescribed current to the bus bar 7 in order to suppress variations in the current detection device 1.

Finally, a resin is filled from the upper surface of the case 2 and hardened in order to secure reliability for in-vehicle use such as water resistance and vibration resistance. Thereby, the core 3, the substrate 4,
The bus bar 7 is fixed.

According to the current detecting device 1 having the above-described structure, an electric circuit is connected to the terminal portion 7a of the bus bar 7 passing through the hollow portion 3b of the core 3, and an external device is attached to the connecting terminal 2a. Similarly, the current flowing through the electric circuit can be measured.

[0020]

According to the present invention, the current detecting device 1 has the above-described structure, so that all the circuit elements 6 mounted on the substrate 4 can be formed by surface mounting components, thereby simplifying the production process. Is done. In addition, since the bus bar 7 is pre-installed, the current detection device 1 can be easily evaluated, and there is no need to insert the bus bar into the current detection device 1 for mounting in a vehicle, thereby simplifying the process. further,
Since the bus bar 7 is assembled to the core 3 in advance and it is not necessary to provide an opening for inserting the bus bar together with the case as in the related art, the hollow portion of the core 3 necessary for forming the opening is required. Since the inner diameter of 3b is reduced by the thickness of the case 2, the size of the core 3 can be reduced, which is advantageous in terms of cost.

A gap 3a is provided on the short side 3c of the core 3 and the core 3 is arranged in the case 2 so that the short side 3c is perpendicular to the upper surface of the case 2.
The height direction of the current detection device 1 can be suppressed,
The current detection device 1 can be reduced in size.

Further, by providing the surface mount type magneto-electric conversion element 5 in the notch 4a of the substrate 4, the gap 3a of the core 3 can be minimized, and the magnetism collecting effect is not reduced. Further, it is possible to realize a current detection device that is hardly affected by disturbance noise.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of a current detection device according to the present invention.

FIG. 2 is a front view of the current detection device shown in FIG.

FIG. 3 is a sectional view taken along line AA of the current detection device shown in FIG. 2;

FIG. 4 is a sectional view taken along line BB of the current detection device shown in FIG.

FIG. 5 is an explanatory view showing a state where a magnetoelectric conversion element is mounted on a substrate of the current detection device according to the present invention.

FIG. 6 is an explanatory diagram showing a conventional current detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Current detector 2 ... Case 2a ... Connection terminal 3 ... Core 3a ... Gap part 3b ... Hollow part 3c ... Short side part 3d ... Long side part 4 ... Substrate 4a ... Notch 4b Hole 4c Terminal 5 Magnetoelectric conversion element 5a Lead 5b Body 6 Circuit element 7 Bus bar 7a Terminal part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G016 CA03 CB13 CD13 CF00 2G017 AA02 AD05 AD53 2G025 AA03 AA05 AB01 AB02 AC02

Claims (3)

[Claims] A current for detecting a change in magnetic flux generated in the core as a current by disposing a magnetoelectric conversion element in the gap of a core fixed in a case having a gap provided on one side of a substantially rectangular shape and detecting the change as a current In the detection device, the case has an open top surface, the core has the gap portion on one side, and the core is disposed so that the one side is substantially perpendicular to the top surface of the case, and the magnetoelectric conversion element is a substrate. Is disposed in a notch or a hole provided in a part of the case, the substrate is mounted in the case substantially parallel to an upper surface of the case, and a bus bar is inserted through a hollow portion of the core. A current detection device, which is provided. 2. The current detection device according to claim 1, wherein the core is rectangular and has the gap on a short side. 3. The device according to claim 1, wherein the magnetoelectric conversion element is a surface mount type, and a side where a height of a main body protruding vertically from a connection terminal is larger is located in a notch or a hole of the substrate. Or the current detection device according to claim 2.