JP2589275B2 - Insulation cap for current detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detector using a magneto-electric conversion element such as a Hall element, and more particularly, to improving the positioning accuracy of a substrate on which a Hall element and the like are mounted and improving the insulation between the two. The improvement of simple insulating caps.

[0002]

2. Description of the Related Art A facsimile or a modem requires an element or a device for detecting a control state of a telephone line, that is, presence / absence of a line loop current and polarity reversal due to telephone on-hook, off-hook or converter operation. Conventionally, a reed relay or a photocoupler has been inserted into a telephone line for this purpose. However, there is a drawback that the minimum current value that can be detected by a reed relay, a photocoupler, or the like is relatively large, and the insertion impedance (resistance) increases to increase the loss.

For this reason, a current sensor using a magnetoelectric conversion element has recently been developed, and a sensor having improved sensitivity and insertion loss has appeared. As the magnetoelectric conversion element, for example, a Hall element is used, and the Hall element 5 has a narrow gap 3 formed by cutting a magnetic material such as ferrite as shown in FIG. And a coil 2 wound around a part of the core 1 around the core 1
The magnetic field in the core gap generated by applying a current to the Hall element acts on the Hall element to detect the intensity and direction of the current. The Hall element 5 is mounted on a substrate 6 made of alumina or the like, and is positioned so that the Hall element 5 is disposed in an appropriate state in the gap.

A detector having such a structure detects the value of an input current (current flowing through a coil winding) as a value of an output voltage (output terminal voltage of a Hall element). In use, there are many electrical regulations to protect the line. One of the requirements is to ensure electrical insulation between the line and the device connected to it.For example, when used for detecting loop current in a subscriber telephone line, the primary coil and the secondary coil must be connected. It is required to ensure a withstand voltage value with the next side (current sensor output terminal) of 4 kVAC / 1 min or more.

Conventionally, in order to ensure such insulation, as shown in FIG.
The insulating film sheet 7 is interposed between the upper end surface 1a of the first and second substrates. Although the space between the gaps is small, the Hall element and other circuit patterns and elements of the substrate are shielded from the core by the film sheet 7 and the alumina substrate, respectively, so that a sufficient withstand voltage can be maintained. it can. The current detector having such a configuration is a resin 1 as shown by a dotted line.
0 is integrated with the mold.

FIG. 5 is a schematic block diagram of the current detector shown in FIG. 4. The value of the magnetic field detected by the Hall element 5 is converted into a voltage, generated at the terminal of the Hall element, and amplified by the amplifier 11. Above, the comparator 12 compares the current value with a predetermined set value to determine the presence / absence and polarity of the current.
By the way, in order to position the substrate 6 and the upper end surface 1a of the cutout portion of the core in parallel and accurately position the Hall element 5 inside the cutout, conventionally, the coil 2 is formed as shown in FIG. End side on lower side (lower side in the figure) 1b
Is formed in parallel with the upper end surface 1a, and the back surface of the substrate 6 is adhered to the end side 1b in close contact.

In the current detector having such a structure, the back surface of the substrate 6 and the edge 1b of the core are temporarily fixed with an adhesive or the like, and the periphery thereof is fixed with a resin 10. If there is a slight variation in the thickness of the agent, the edge 1 of the core
The parallel positional relationship between the substrate b and the substrate 6 may be impaired, and the angle of the magnetic field lines acting on the Hall element in the core cutout may change, resulting in a variation in characteristics that lowers the detection sensitivity. Was. In addition, a large amount of time is required for processing the insulating sheet 7 and for positioning and attaching the sheet from the Hall element 5 to the upper surface of the substrate. Further, when heating is performed to cover the resin in a later step, the sheet 7 becomes In such a case, complicated repair work such as removing the resin material and re-covering the sheet is required.

In order to solve such a problem, the applicant of the present application has disclosed in Japanese Patent Application No. 1-264719, one end 2 of an annular core 21 having a notch 20 as shown in FIG.
1b, the coil 26 is wound around the
Is inserted into the core from the notch so that the magnetoelectric conversion element is located in the cutout of the core, and further, the coil is not formed on the upper surface of the board on which the magnetoelectric conversion element is mounted. The coil is formed so as to face the core end 21a. Further, an insulating cap 30 is attached to the outer surface of the core end 21a where the coil is not formed, and the magnetoelectric conversion element 23 and the spacer 31 are interposed via the insulating cap 30. A current detector was proposed in which positioning was performed by contacting the core with the end of the core. The spacer 31 may be integrally formed with the insulating cap 30 as shown in FIG. Also, as shown in FIG. 6C, a small projection 31a provided on the spacer 31 protruding from the insulating cap.
There is also disclosed a configuration in which is fitted into a recess or groove 40 provided in a printed circuit board.

However, in the conventional method of supporting a substrate using an insulating cap, even when the spacer 31 or the like is used, it is necessary to bond several places when positioning the substrate.
There is a drawback that the number of installation steps is increased. In addition, the inner diameter of the cap 30 fitted to the core end 21a is set to be larger than the core end in advance for reasons such as a need to prevent the mounting workability from being lowered, and the cap is fitted to the core end. When they are combined, some backlash may remain between them, but the presence of the backlash causes the core to tilt (displace) with respect to the substrate and peel off when the current detector as a whole is integrally molded with resin. Cause.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and has improved workability and work accuracy when positioning a board on which a Hall element is mounted in a notch of an annular core, and has complicated assembly. It is an object of the present invention to provide an insulating cap of a current detector using a magnetoelectric conversion element that can obtain an insulating structure that does not involve peeling during operation or molding.

[0011]

SUMMARY OF THE INVENTION To achieve the above object, the present invention includes an annular core having a notch, a coil wound around a part of the core, and a substrate having a magnetoelectric conversion element mounted on an upper surface. The substrate is arranged so that the magnetoelectric conversion element is positioned within the notch of the core, and the lower surface of the substrate faces the coil winding portion side, and the upper surface on which the magnetoelectric conversion element is mounted has a coil not formed. A current detector facing the forming portion side, the other side of the core not forming the coil and adjacent to the magnetoelectric conversion element is covered with an insulating cap; In the one in which the magnetoelectric conversion element is brought into contact with the other end side of the core via the positioning, the insulating cap is drawn out laterally from the cap body fitted to the other end side and the cap body. U-shaped board pressure piece The substrate pressing piece comprises an upper thick portion, a lower bottom piece, and a pressing recess formed between the thick portion and the bottom piece, and a substrate edge is provided in the pressing recess. Along with fitting and supporting, the thick portion forms a space for arranging the magnetoelectric conversion element on the substrate, and a support piece for supporting both sides of the coil is provided on the lower surface of the bottom piece of the substrate pressure piece. It is characterized by being protruded.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the preferred embodiments shown in the accompanying drawings. 1 (a), 1 (b) and 1 (c) are a front view, a right side view and a plan view showing a configuration of an embodiment of a current detector to which the present invention is applied, and FIG. 2 is an exploded perspective view of the current detector. FIG. 3 is a perspective view showing an assembled state. An insulating substrate 25 on which a magneto-electric conversion element (Hall element) 23 is mounted is arranged in the notch 20 of the annular core 21 having the notch 20, and the upper surface of the substrate 25 on which the magneto-electric conversion element 23 is mounted is further removed. A configuration in which the back surface of the substrate 25 is opposed to the end 21b on the side on which the coil 26 is formed and the back surface of the substrate 25 is opposed to the non-coil forming end side 21a side is the same as the conventional example described above. While holding the substrate horizontally by holding the board edge, and holding the coil 26 on the lower surface of the board holding piece 32 (bottom piece 32c).
Are different in the configuration in which two plate-shaped support pieces 33 that support both sides of the support member protrude.

That is, the insulating cap 30 of the present invention is formed by press-forming in a state in which an insulating resin material such as polyimide is melted.
And a cap main body 31 fitted to an end 21a adjacent to the magnetoelectric conversion element and an end portion where the coil 26 is not formed. An extended U-shaped substrate pressing piece 32 and a support piece 33 projecting from the lower surface of the substrate pressing side 32 to protect both sides of the coil formed on the end side 21b on the coil forming side of the core. It has. The cap body 31 is formed by molding an insulating sheet into a bag or a tube. Such a cap-shaped insulating means can be mounted simply by covering it from the end of the edge 21a, and is hard to fall off. Therefore, it is possible to prevent the insulating means from falling off when the resin is covered. The withstand voltage between the coil 26 on the primary side and the magnetoelectric conversion element on the secondary side is ensured by the insulating cap 30 and the insulating substrate 25, respectively.

The substrate pressing piece 32 includes a pressing concave portion 32a for holding and holding the edge of the substrate 25 in a horizontal position, and
A thick portion 32b is provided between the upper surface of the substrate 25 supported by the recess 32a and the lower surface of the non-coil forming edge 21a to form a space for disposing the magnetoelectric conversion element 23. The space between the recesses 32a and the pinching force are configured so that the edge of the substrate can be pinched with a predetermined sufficient force to horizontally support the posture of the insulating cap with respect to the substrate. Also, the relationship between the substrate and the entire insulating cap is set to be parallel. For this reason, after applying an adhesive to the joint between the cap body 31 and the end side 21a,
The board is temporarily fixed by a simple operation of fitting the board into the recess 32a, that is, assembling the current sensor to the board,
Positioning is completed. In this state, by molding the current detector including the substrate with the resin, it is possible to obtain a molded product with no displacement between the components.

The presence of the thick portion 32b functioning as a spacer allows the coil 26 and the substrate 25
And the parallel posture can be accurately secured. Conventionally, since the upper surface of the substrate was opposed to the coil side, it was difficult to mount a spacer so as to contact the coil portion.
By positioning the position of the coil on the opposite surface of the substrate as in the present embodiment, a part of the substrate pressing piece can function as a spacer. Substrate 25 and coil 26
By ensuring a parallel posture with the above, variations in characteristics can be reliably suppressed.

Next, the plate-shaped support piece 33 for supporting the coil 26 has a shape that hangs down along both sides of the coil 26, and the core is displaced with respect to the cap body 31, that is, non-coil formation. Rotation on the coil side around the end side 21a can be prevented.

As shown in FIG. 2, the procedure for attaching the insulating cap to the annular core provided with the coil is such that the cap body 31 is fitted to the side 21a on which no coil is formed, and at the same time, the side 21b provided with the coil is connected to the side 21b. Two support pieces 3
3 and 33 (below the bottom piece 32c of the substrate pressing piece 32), and the protrusion 21c at the tip of the edge 21b is attached to the bottom piece 21c.
To prevent falling off. When assembling (temporarily fixing) the substrate 25 provided with the electromagnetic transducer 23 to the core to which the insulating cap has been attached in this manner,
As shown in FIG. 2, the substrate 25 is
And finally positioned as shown in FIG. At this time, the position of the magnetoelectric conversion element 23 on the substrate is, of course, set in advance so as to be located within the notch 20.

[0018]

As described above, according to the insulating cap of the current detector using the magneto-electric conversion element of the present invention, the workability when positioning the board on which the Hall element is mounted in the notch of the annular core is improved. It is possible to improve the working accuracy and obtain an insulating structure that does not involve complicated assembly work or peeling during molding.

[Brief description of the drawings]

FIGS. 1 (a), 1 (b) and 1 (c) are a front view, a right side view and a plan view showing a configuration of an embodiment of a current detector to which the present invention is applied.

FIG. 2 is an exploded perspective view of the current detector.

FIG. 3 is a perspective view showing an assembled state.

FIG. 4 is a diagram showing a configuration of a conventional current detector.

FIG. 5 is a schematic block diagram of the current detector of FIG. 4;

6 (a), (b) and (c) are an explanatory diagram of a configuration of a current detector proposed by the present applicant, a perspective view of an insulating cap, and an explanatory diagram of a configuration of another current detector.

[Explanation of symbols]

Reference Signs 20 notch, 21 annular core, 21a non-coil forming edge, 21b coil forming edge, 23 magnetoelectric conversion element (Hall element), 25 substrate, 26 coil, 30 insulating cap, 31 cap body, 32 substrate holding piece,
32a clamping recess, 32b thick part, 32c bottom piece,
33 support pieces,

Claims (2)

(57) [Claims] An annular core having a notch, a coil wound around a part of the core, and a substrate having a magnetoelectric conversion element mounted on an upper surface thereof, wherein the magnetoelectric conversion element is provided in a notch of the core. A current detector in which the substrate is arranged so that the element is located, and the lower surface of the substrate faces the coil winding portion side, and the upper surface on which the magnetoelectric conversion element is mounted faces the coil non-forming portion side. The other end of the coil non-forming portion adjacent to the magnetoelectric conversion element is covered with an insulating cap, and the magnetoelectric conversion element is brought into contact with the other end of the core through the insulating cap. Wherein the insulating cap includes a cap body fitted to the other end side, and a U-shaped board pressing piece led out from the cap body to the side. Is the upper thick part, the lower bottom piece, And a pressing recess formed between the bottom piece and the press-fitting recess. The board edge is fitted and supported in the pressing recess, and a space for disposing the magnetoelectric conversion element on the board by the thick portion is provided. An insulating cap for a current detector, wherein the insulating cap is formed. 2. The insulating cap for a current detector according to claim 1, wherein support pieces for supporting both sides of said coil are projected from a lower surface of a bottom piece of said substrate pressure piece.