JP2003017347A - Current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current sensor which minimizes its external shape and also can eliminate the need for a potting. SOLUTION: A current sensor is provided with troidal cores which pass a magnetism generated by a current flowing in an electric wire and also is provided with a gap and a coil, a hole element 13 for detecting the magnetism, an annular part for holding the troidal cores 3, and a substrate 1 which is provided integrally with the annular part and is provided with a projected part provided protuberantly from the annular part. The troidal cores are held by the annular part of the substrate 1 in such a way that the gap turns to the projected part of the substrate 1, the hole element 13 is inserted in the gap between the troidal cores and is connected with the substrate 1, a pattern for connecting a connection part for external circuit connecting with the element 13 is formed on the projected part of the substrate 1, and the troidal cores are wound on an insulating tape 13 along with the substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current sensor for detecting a current flowing through an electric wire or the like.

[0002]

2. Description of the Related Art Some current sensors use a toroidal core and a Hall element to detect a current. Such a current sensor is shown in FIG. The current sensor of FIG. 9 detects a current flowing through the electric wire 201, and
1 and an annular core portion 110. Board 10
1 has a hole 101A through which the electric wire 201 passes,
So that the hole 101A is located at the center of the core portion 110,
The core portion 110 is arranged.

The core portion 110 has a toroidal core and a Hall element inside. Such a core part 11
0 is created as follows. The six pin terminals 121 protruding from the core portion 110 are for the coil wound around the toroidal core and for the Hall element having four terminals.

The pin terminals 121 for the Hall element are connected as follows. As shown in FIG. 10, the terminal 111A of the Hall element 111 is bent into an L shape. At the bent portion of the terminal 111A, the pin terminal 121
Is attached. At this time, the bent portion of the terminal 111A and the pin terminal 121 are bound and fixed by the thin wire 122, and then soldered.

In this way, the pin terminals 121 are attached to the four terminals 111A of the Hall element 111, respectively. The pin terminal 121 is also attached to the lead wire of the coil wound around the toroidal core. On the other hand, a gap is provided in the toroidal core, and the Hall element 111 is inserted in this gap. After that, the insulating tape 131 is wound around the toroidal core with the pin terminals 121 exposed.

Thus, the core portion 110 having the six pin terminals 121 is formed. On the other hand, the substrate 101 has 6
A book terminal 102 is provided. These terminals 102
To each pin terminal 121 of the core portion 110.

After that, in order to fix the core portion 110 mounted on the substrate 101, the substrate 101 is placed in a resin case.
And the potting resin is filled in this resin case. After that, the potting resin is solidified and the core portion 110 mounted on the substrate 101 is fixed.

[0008]

The conventional current sensor has the following problems. That is, the core portion 110
In order to mount the semiconductor device on the substrate 101, it is necessary to connect the pin terminal 121 to the hall element 111. Further, a resin case is required to fix the core portion 110 mounted on the substrate 101, and the core portion 110 is put in the resin case, so that the outer shape of the current sensor becomes large.
Further, the conventional current sensor is potted with potting resin after being put in a resin case. At this time, the substrate 101 and the core portion 110 are affected by thermal stress due to expansion and contraction caused by the temperature change of the potting resin.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a current sensor which has a small outer shape and can eliminate the need for potting.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 allows a magnetism generated by an electric current flowing through an electric wire to pass therethrough, and detects an annular core having a gap and a coil and magnetism. The magnetic core comprises: a magnetic conversion element; an annular portion that holds the annular core; and a substrate that includes an annular portion that is integrally provided with the annular portion and that protrudes from the annular portion. Is such that the gap faces the protruding portion of the substrate,
The magnetic conversion element is held on an annular portion of the substrate,
Inserted into the gap of the annular core and connected to the substrate, a pattern for connecting the connecting portion for external circuit connection and the magnetic conversion element is formed on the protruding portion of the substrate, and the annular core is A current sensor characterized by being wound with an insulating tape together with the substrate.

According to the above construction, since the annular core is held by the annular portion of the substrate, and the insulating core is wound around and fixed to the substrate, the conventional case can be eliminated. As a result, it is possible to reduce the size and weight of the current sensor. Further, since potting with a urethane resin or the like is unnecessary, the influence of thermal stress can be eliminated.

According to a second aspect of the present invention, in the current sensor according to the first aspect, the substrate and the annular core wound with the insulating tape are fixed by a resin.

According to the above construction, since the annular core wound with the insulating tape and the substrate are fixed by the resin, the annular core can be securely fixed to the substrate.

According to a third aspect of the present invention, in the current sensor according to the first or second aspect, the connecting portion is a lead wire connected to an external circuit. According to a fourth aspect of the present invention, in the current sensor according to the first or second aspect, the connecting portion is a lead terminal connected to an external circuit. According to a fifth aspect of the present invention, in the current sensor according to the first or second aspect, the connecting portion is a connector connected to an external circuit.

According to the above construction, the connection with the external circuit is made by the lead wire, the lead terminal and the connector, so that the connection with the external circuit is simplified.

[0016]

Next, a first embodiment of the present invention will be described.
3 will be described in detail with reference to the drawings.

[First Embodiment] FIGS. 1 and 2 show a current sensor according to this embodiment. The current sensor of FIG. 1 is composed of a substrate 1 and a core portion 2. Note that FIG. 2 shows a state in which a part of the core portion 2 is cut out in order to clearly show the Hall element 13 described later.

The substrate 1 has an annular portion 1 as shown in FIG.
1 and a protruding portion 12. The annular portion 11 is a circular substrate portion, and the protruding portion 12 is a square substrate portion. Annular portion 11 and protruding portion 12
Form a substrate made of insulating material.

The annular portion 11 is for mounting the core portion 2, and the outer diameter R and the inner diameter r thereof are the same as those of the core portion 2. A pattern 12A and through holes 12B and 12C are provided on the surface of the protruding portion 12. The four through holes 12B are provided on one end side of the projecting portion 12 and the annular portion 11, and the four through holes 12C are provided on the other end side of the projecting portion 12.
The four patterns 12A electrically connect the through holes 12B to the through holes 12C, respectively. Also,
Lead wires 14 are respectively connected to the through holes 12C as connecting portions. The lead wire 14 is for connecting another external circuit (external circuit) to the current sensor.

A Hall element 13 as a magnetic conversion element is attached to the through hole 12B. The Hall element 13 detects magnetism and converts it into a voltage. For this,
The hall element 13 has four terminals. Two of the four terminals are for a current for passing a current necessary for magnetic detection, and the remaining terminals are for a voltage that outputs a voltage according to the detected magnetism. Then, as shown in FIG. 4A, the surface 13A of the square-shaped Hall element 13 in the shape of a thin plate.
However, the four terminals 13B of the Hall element 13 are arranged so as to intersect with the circumferential direction of the annular portion 11 of the substrate 1 as shown in FIG.
As shown in (b), the through holes 12B are soldered. As a result, the Hall element 13 is arranged so as to enter the gap of the toroidal core described later.

As shown in FIGS. 5 and 6, the core portion 2 has an annular toroidal core 21. The toroidal core 21 is for passing an electric wire to be measured, and magnetism is generated in the toroidal core 21 by a current flowing through the electric wire. Toroidal core 21
Has a winding used for current detection. Reference numeral 22 is a lead wire of the winding wire. The toroidal core 21 is provided with a gap 21A.

The toroidal core 21 of this structure is arranged in the annular portion 11 of the substrate 1. At this time, the toroidal core 21 is arranged so that the gap 21A of the toroidal core 21 faces the protruding portion 12 of the substrate 1, that is, the hall element 13 is located in the gap 21A of the toroidal core 21.
Is placed. When magnetism is generated in the toroidal core 21, this magnetism passes through the hall element 13 and the hall element 1
3 generates a voltage according to the magnetism in the toroidal core 21.

The toroidal core 21 arranged on the annular portion 11 of the substrate 1 is attached to the annular portion 11 by the insulating tape 23.
Together with taping, they are integrated. The insulating tape 23 is used for insulating the winding wire. Moreover, in this embodiment, the insulating tape 23 is used to fix the toroidal core 21 to the annular portion 11. Toroidal core 21 integrated with the annular portion 11
Is impregnated with epoxy resin to form a ring-shaped part 1.
It is fixed at 1. In this way, the toroidal core 21 is attached to the substrate 1.

The current sensor according to this embodiment has the above structure. This current sensor is manufactured as follows.

The Hall element 13 and the lead wire 14 are mounted on the substrate 1 in advance. After winding the toroidal core 21, the hall element 13 is inserted into the gap 21A of the toroidal core 21, and the toroidal core 21 is fitted to the annular portion 11 of the substrate 1. After this, the substrate 1
The toroidal core 21 is taped with the insulating tape 23 together with the annular portion 11 to insulate the winding,
The toroidal core 21 and the substrate 1 are integrated. After this,
Impregnation with epoxy resin completes the fabrication of the current sensor.

[Second Embodiment] In this embodiment, a lead terminal is used instead of the lead wire 14 of the first embodiment. Therefore, as shown in FIG. 7, a mounting hole 12D for the lead terminal 15 is formed in the projecting portion 12 of the substrate 1. In this embodiment, the same or similar components as those of the current sensor of FIG. 1 described above are designated by the same reference numerals. Mounting hole 1
Simultaneously with the formation of 2D, a pattern for connecting the lead terminal 15 inserted in the mounting hole 12D to the through hole 12B is formed in the protruding portion 12.

When assembling the current sensor, the lead terminal 15 is inserted into the mounting hole 12D and soldered to mount the lead terminal 15 on the protruding portion 12 of the substrate 1 in advance. After that, as in the first embodiment, the core portion 2 is attached to the substrate 1 to manufacture the current sensor.

[Third Embodiment] In this embodiment, a connector is used in place of the lead wire 14 of the first embodiment. For this purpose, as shown in FIG.
The mounting hole for mounting 6 is formed on the protruding portion 12 of the substrate 1.
Empty In this embodiment, the same or similar components as those of the current sensor of FIG. 1 described above are designated by the same reference numerals. Simultaneously with the formation of the mounting hole, a pattern for connecting the connector 16 inserted in the mounting hole to the through hole 12B is formed on the protruding portion 12.

When assembling the current sensor, the connector 16 is previously mounted on the projecting portion 12 of the substrate 1 by inserting the connector 16 into the mounting hole and soldering. After that, the core portion 2 is attached to the substrate 1 as in the first embodiment.

The first to third embodiments have been described above. According to the current sensors of the first to third embodiments, it is possible to eliminate the conventional resin case, and it is possible to reduce the size of the current sensor. Further, the conventional current sensor is potted with the potting resin after being put in the resin case, but the current sensors according to the first to third embodiments can eliminate the need for potting. As a result, it is possible to eliminate the influence of thermal stress due to expansion and contraction caused by the temperature change of the potting resin.

Further, according to the first to third embodiments, the substrate 1
Since the lead wire 14, the lead terminal 15 or the connector 16 is attached to, the connection with an external circuit can be facilitated.

Although the first to third embodiments of the present invention have been described in detail above, the specific structure is not limited to those of the first to third embodiments, and a design within a range not departing from the gist of the present invention is possible. Even if there are changes, they are included in the present invention. For example,
The pattern 12A of the substrate 1 may be provided on both sides of the substrate 1.

[0033]

As described above, according to the first aspect of the present invention, the annular core is held by the annular portion of the substrate and is wound on the insulating tape to be fixed to the substrate. Therefore, a conventional case is unnecessary. Can be As a result, it is possible to reduce the size and weight of the current sensor. Further, since potting with a urethane resin or the like is unnecessary, the influence of thermal stress can be eliminated.

According to the second aspect of the present invention, since the annular core wound with the insulating tape and the substrate are fixed by the resin, the annular core can be securely fixed to the substrate.

According to the third, fourth and fifth aspects of the present invention, since the connection with the external circuit is made by the lead wire, the lead terminal and the connector, the connection with the external circuit is simplified.

[Brief description of drawings]

FIG. 1 is a plan view showing a current sensor according to a first embodiment of the present invention.

FIG. 2 is a front view showing a current sensor according to the first embodiment.

3 is a plan view showing the substrate of FIG. 1. FIG.

FIG. 4 is an explanatory diagram for explaining attachment of a Hall element.

FIG. 5 is an explanatory diagram for explaining attachment of the toroidal core.

FIG. 6 is an explanatory diagram for explaining attachment of lead wires to the substrate of FIG.

FIG. 7 is a perspective view showing a current sensor according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing a current sensor according to a third embodiment of the present invention.

FIG. 9 is a perspective view showing a conventional current sensor.

FIG. 10 is a perspective view showing a state of connection between a hall element and a lead wire.

[Explanation of symbols]

1 substrate 11 annular part 12 protruding part 12A pattern 12B, 12C through hole 12D mounting hole 13 Hall element 13A surface 13B terminal 14 lead wire 15 lead terminals 16 connectors 2 core parts 21 toroidal core 21A gap 22 lead wire 23 insulating tape

Continued front page    (72) Inventor Naoki Mogi             5-30 Chiyoda, Sakado City, Saitama Stock             Company Tamura Seisakusho Office F-term (reference) 2G025 AA05 AB02 AC01                 5E081 AA05 AA18 BB03 CC30 DD13                       DD14 DD15

Claims (5)

[Claims] 1. A ring-shaped core (21) for passing magnetism generated by a current flowing through an electric wire and having a gap (21A) and a coil, a magnetic conversion element (13) for detecting magnetism, and the ring-shaped core (21). ) Holding an annular portion (11),
A substrate (1) provided integrally with the annular portion (11) and having a protruding portion (12) protruding from the annular portion (11), and the annular core (21). Is held by the annular portion (11) of the substrate (1) such that the gap (21A) faces the protruding portion (12) of the substrate (1), and the magnetic conversion element (13) is the annular portion. It is inserted into the gap of the core (21) and connected to the substrate (1), and the projecting portion (12) of the substrate (1) is provided with a connecting portion for external circuit connection and the magnetic conversion element (13). A current sensor characterized in that a pattern for connection is formed, and the annular core (21) is wound with an insulating tape (23) together with the substrate (1). 2. The current sensor according to claim 1, wherein the substrate (1) wound with the insulating tape (23) and the annular core (21) are fixed by a resin. 3. The current sensor according to claim 1, wherein the connection portion is a lead wire (14) connected to an external circuit. 4. The current sensor according to claim 1, wherein the connection portion is a lead terminal (15) connected to an external circuit. 5. The current sensor according to claim 1, wherein the connection portion is a connector (16) connected to an external circuit.