JPH0622220Y2 - Current-voltage converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a current-voltage converter that monitors a current flowing through an electric device or the like and outputs a voltage signal according to a change in the current.

<< Prior Art >> Such a current-voltage converter has a structure in which a coil 4 is wound around a ring-shaped core 3 which is formed in a ring shape so that both ends 1 and 2 closely face each other as shown in FIG. The path 5 is formed, and the Hall element 7 is arranged in the gap 6 between the ends 1 and 2 so as to intersect the magnetic flux passing through the magnetic path 5 at a substantially right angle.

Then, when the coil 4 is connected to the circuit of the apparatus main body (not shown) and the connection cable of the electric device to be measured is passed through the annular core 3, the magnetic flux passing through the annular core 3 according to the current flowing through the electric device is generated. Since this changes, the change in magnetic flux is detected by the Hall element 7, the current value flowing through the electric device is converted into a voltage value, and the voltage value is output as a signal.

<< Problems to be Solved by the Invention >> In the structure in which the Hall element 7 is arranged in the gap 6 between the ends 1 and 2 of the annular core 3 in this way, a part of the magnetic path 5 is blocked due to the gap 6. The magnetic flux in that portion weakens, and since the weakened magnetic flux is detected by the Hall element 7, there is a problem that the detection sensitivity decreases. In addition, in the gap 6, the hall element 7
Since there is no means for positioning, the position of the Hall element 7 is slightly deviated in the left-right and up-down directions due to errors during manufacturing and assembly, or shocks and vibrations during use, resulting in unstable detection accuracy. I got it.

The present invention has been made in view of the above points, and the magnetic flux is not weakened at the place where the hall element is installed, and the hall element is attached at a proper position with respect to the annular core, and stable detection sensitivity and accuracy can be obtained. An object is to provide a current-voltage converter.

<< Means for Solving the Problems >> In order to achieve the above object, the present invention has a structure in which a coil is wound around an annular core formed entirely in an annular shape so that both ends closely oppose each other, and both ends of the annular core are A current-voltage conversion device in which Hall elements are arranged so as to intersect the magnetic flux passing through the annular core substantially at right angles between the parts, and the both ends of the annular core are connected by an auxiliary core holding the Hall element, The auxiliary core is formed in a substantially U-shaped cross section, and receives a bottom wall that receives a lower surface in the vicinity of both ends of the annular core and rises at a substantially right angle from the bottom wall and receives side surfaces of both ends of the annular core. A pair of side walls is provided, and a positioning projection protruding inward is formed on the inner surface of the pair of side walls, and a step formed by the projection holds a gap between both ends of the annular core. Bottom wall and side wall of the auxiliary core And a positioning recess is formed by the end faces at both ends of the annular core, and the Hall element is disposed in the positioning recess.

<< Embodiment >> An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway exploded perspective view showing a main configuration of a current-voltage converter according to an embodiment of the present invention.

In the figure, a synthetic resin main body 10 is formed in a box shape with an open upper surface, and from the lower surface, a cylindrical portion 11, 12 and a surrounding wall 1 lower than the cylindrical wall 11 and 12 surrounding the outside thereof.
3, 14 are integrally formed. In the space portions 15 and 16 formed by the cylindrical portions 11 and 12 and the surrounding walls 13 and 14, a plurality of thin iron pieces formed in an annular shape so that both end portions 17 and 18 closely face each other are laminated. Ring core 1
9, a coil 20 wound around the annular core 19, and an auxiliary core 2 for connecting between both ends 17 and 18 of the annular core 19.
1 and an annular coil unit 22 which is held by the auxiliary core 21 and includes a Hall element 30 disposed between both ends 17 and 18 of the annular core 19.

The auxiliary core 21 has a substantially U-shaped cross section, and is attached to both ends 17 and 18 of the annular core 19 so as to straddle the bottom wall 23 in the vicinity of the ends 17 and 18, respectively. It has side walls 24 and 25 which rise from the bottom wall 23 at a substantially right angle and receive the side surfaces of both end portions 17 and 18. Positioning protrusions 26 and 27 are formed on the inner surfaces of the side walls 24 and 25 so as to protrude inward.
A step portion 28 formed by 27 holds the distance between the both end portions 17, 18. Then, the bottom wall 23 of the auxiliary core 21
And side walls 24, 25 and both ends 17, 1 of the annular core 19.
A positioning recess 29 is formed by the end surface of the Hall element 8, and the Hall element 30 is disposed in the recess 29.

As shown in FIGS. 5 and 6, the Hall element 30 has four electrode terminals 32 extending from the side surface of the element body 31, and lead wires 33 are connected to the electrode terminals 32, respectively. In addition, the width dimension of the element body 31 of the Hall element 30 is slightly smaller than the dimension between the protrusions 26 of the auxiliary core 19, and the thickness dimension is the end portions 1 of the annular core 19.
It is slightly smaller than the dimension between 7 and 18. Further, the height dimension is formed to be substantially equal to the thickness of the annular core 19. Therefore, the Hall element 30 is always held in a fixed position so that it is just accommodated in the recess 29, and the magnetic flux enters the detection surface at a right angle and passes through. The annular core 19 in which the Hall element 30 is positioned in the recess 29 and the coil 20 is wound in this manner is further covered with an insulating tape, and the coil lead wire connected to the coil 20 from between the tapes. Only the lead wire 33 connected to the electrode terminals 32 of the Hall element 30 is led out. Then, the main body 10 has an opening 37 for escaping the tubular portions 11, 12.
A circuit board 39 having 38 is covered and attached.

In each of the coil units 22 thus configured, when a current is applied to the coil 20, a magnetic field is generated and the magnetic flux along the magnetic path 34 crosses the Hall element 30 at a right angle. This magnetic flux is weakened because a gap is formed between the end portions 17 and 18 of the annular core 19 in the related art, but in this structure, the auxiliary core 21 is provided between the end portions 17 and 18. Therefore, it passes through the Hall element 30 without being weakened. Since this Hall element 30 is positioned and held by the auxiliary core 21, the detection position does not shift.

In addition, as shown in FIG. 2, the coil unit 22 arranged in each of the space portions 15 and 16 in the main body 10 has a Hall element 30 with respect to a line X connecting the centers of the space portions 15 and 16. It is arranged so as to be tilted inward by about 45 °. This is to prevent the magnetic fluxes of the coil units 22 adjacent to each other from being detected by the Hall element 30 on the other side. That is, when a magnetic field is generated in each coil unit 22, each magnetic flux spreads outward concentrically and leaks. If it intersects at right angles with the leaking magnetic flux of, the leaking magnetic flux is detected by the Hall element 30 and the detection accuracy is lowered. In consideration of this, when the Hall elements 30 are arranged in a form inclining toward each other with an angle of about 45 ° with respect to the line X connecting the centers of the two space portions 15 and 16, the adjacent Hall elements 30 are adjacent to each other. The magnetic flux leaking concentrically from the coil unit 22 becomes parallel to the detection surface of the Hall element 30. Therefore, even if a plurality of coil units 22 are arranged in the same main body 10, a decrease in detection accuracy is prevented, and a compact size can be achieved when using a plurality of coil units 22 at the same time. The arrangement angle of the Hall element 30 may be arbitrarily set as long as the detection surface of the Hall element 30 is substantially parallel to the adjacent leakage magnetic flux and is not greatly affected by the leakage magnetic flux.

<< Effects of the Invention >> As described above, according to the present invention, the both ends of the annular core are connected by the auxiliary core holding the Hall element, and the auxiliary core is formed in a substantially U-shaped cross section. The bottom wall receives a lower surface in the vicinity of both ends of the annular core, and has a pair of side walls which rises at a substantially right angle from the bottom wall and receives side surfaces of both ends of the annular core. Has a positioning projection protruding inward, and a step formed by the projection holds a gap between both ends of the annular core, and further, a bottom wall and a side wall of the auxiliary core and the annular core. Since the positioning recess is formed by the end surfaces at both ends of the annular element, and the Hall element is disposed in the positioning recess, the stepped portion holds the gap between both ends of the annular core, and With both ends of the annular core like It is possible to eliminate the gap with the hall element. As a result, the auxiliary core is not a simple element holder but an auxiliary core similar to the annular core, so that the magnetic flux is not blocked as much as possible and the magnetic flux passing between the both ends of the annular core can be attenuated. The Hall element is intended to be as small as possible, and therefore, the Hall element exhibits an effect of detecting a change in magnetic flux without constantly degrading the intended detection sensitivity.

[Brief description of drawings]

FIG. 1 is a partially cutaway exploded perspective view showing a main part configuration of a current-voltage converter according to an embodiment of the present invention, and FIG. 2 is a plan view showing the main part of the same device as shown in FIG. Is a partially enlarged plan view of a coil unit of the same apparatus, FIG. 4 is a longitudinal sectional view taken along the line AA in FIG. 3, and FIG. 5 is used in the same apparatus shown in FIGS. FIG. 6 is a front view showing an example of the Hall element, FIG. 6 is a side view of the Hall element shown in FIG. 5, and FIG. 7 is a plan view showing an example of a coil unit in a conventional current-voltage converter. 10 ... Case body, 19 ... Annular core, 20 ... Coil, 21 ... Auxiliary core, 23 ... Bottom wall, 24, 25 ...
Side walls, 26, 27 ... Positioning projections, 28 ... Steps, 2
9: Hall element positioning recess, 30: Hall element.

Claims (1)

[Scope of utility model registration request] 1. A coil is wound around an annular core formed entirely in an annular shape so that both ends closely oppose each other, and a hole is formed between both ends of the annular core so as to intersect the magnetic flux passing through the annular core at a substantially right angle. A current-voltage converter in which elements are arranged,
The both ends of the annular core are connected by an auxiliary core holding the Hall element, the auxiliary core is formed in a substantially U-shaped cross section, and the bottom wall receives the lower surface in the vicinity of the both ends of the annular core. And a pair of side walls that rise from the bottom wall at a substantially right angle and receive the side surfaces of both end portions of the annular core, and the inner surfaces of the pair of side walls are formed with positioning protrusions that protrude inward. A gap formed at both ends of the annular core is held by a step formed by a portion, and a positioning recess is formed by a bottom wall and a side wall of the auxiliary core and end faces at both ends of the annular core, A current-voltage converter in which the Hall element is disposed in a positioning recess.