JP5313024B2 - Through-type current sensor - Google Patents

Description

  The present invention relates to a technology relating to a through-type current sensor using a fluxgate sensor element.

  FIG. 3 is an exploded perspective view of the through-type current sensor disclosed in the following Patent Document 1, and FIG. 4 is an enlarged cross-sectional view of the example shown in FIG. 3 after assembly. It is principal part explanatory drawing shown.

JP 2006-300915 A

  According to these figures, the through-type current sensor 1 includes two fluxgate sensor elements 2, a ferrite core 3 that accommodates the two fluxgate sensor elements 2 in an overlapping manner, and an outer surface 3a of the ferrite core 3. And at least a feedback winding (not shown) wound around.

  Among these, the ferrite core 3 is composed of a one-side core portion 4 and an other-side core portion 5 each of which has an annular shape and is divided into two so as to be able to face each other.

  The one-side core portion 4 and the other-side core portion 5 include lead-out grooves 4a and 5a for pulling out the lead wire 2a included in each accommodated fluxgate sensor element 2.

  In addition, the feedback winding (not shown) wound around the outer surface 3a of the ferrite core 3 is electrostatically shielded by winding a conductor tape such as a copper foil tape around the outside.

  For this reason, according to the through-type current sensor 1 shown in FIG. 3, the fluxgate sensor element 2 as the magnetic detection means can be arranged under the entire circumference symmetric structure. The influence of the external magnetic field can be made extremely small.

  However, the ferrite core 3 in the through-type current sensor 1 shown in FIG. 3 has a problem that the magnetic characteristics are not stable depending on the sintering conditions, and the frequency characteristics of the sensor performance tend to vary.

  Further, since the ferrite core 3 is fragile, it is easy to crack when dropped during use or the like, and is easily cracked. The magnetic resistance caused by the crack entered at that time has an adverse effect depending on the position of the conductor to be measured. There was also the inconvenience of degrading performance characteristics.

  In addition, in order to prevent the above-described cracking, it is effective to wind the magnetic tape, but the magnetic tape itself is expensive, and the winding work becomes complicated and increases the overall cost.

  In view of the above-mentioned problems of the prior art, the present invention effectively contributes to significant improvement in sensor performance and cost reduction by forming a magnetic material incorporated in a through-type current sensor with a high-permeability and tenacious member. It is an object of the present invention to provide a through-type current sensor capable of performing

  The present invention has been made to achieve the above object, and includes a fluxgate sensor element having an annular shape, a small-diameter permalloy case that accommodates the fluxgate sensor elements in a stack, and an opening of the small-diameter permalloy case. A plurality of one-side permalloy thin pieces arranged in a stacking manner, a large-diameter permalloy case that covers the small-diameter permalloy case containing the fluxgate sensor element together with the one-side permalloy thin piece, and an opening in the large-diameter permalloy case The main feature is that at least a plurality of other permalloy flakes arranged in a stacked manner are provided between the portion and the bottom wall portion of the small-diameter permalloy case.

  In this case, the small-diameter permalloy case and the large-diameter permalloy case are provided with slits for deriving each lead wire drawn out from the fluxgate sensor element 12 accommodated in a two-layered manner on the outer peripheral wall side. It is preferable to provide it at a position.

  According to the present invention, both the small-diameter permalloy case and the large-diameter permalloy case have high magnetic permeability and are not broken, so that the magnetic characteristics are stabilized by eliminating the adverse effects of magnetic resistance, etc. These characteristics can be greatly improved.

  The small-diameter permalloy case and the large-diameter permalloy case are formed relatively thick, and the one-side permalloy thin piece and the other-side permalloy thin piece are thinly formed. Therefore, it can be used in a wide frequency band.

  Furthermore, when the slits of the small-diameter permalloy case and the large-diameter permalloy case are provided on the outer side opposite to the position of the conductor to be measured, the current can be measured without deteriorating the sensor performance. it can.

  Moreover, unlike the case of using a ferrite material, the small-diameter permalloy case and the large-diameter permalloy case can be formed at low cost by manufacturing a mold, and various characteristics can be stabilized over a wider temperature range. Therefore, it is possible to provide a product with a wide adaptive temperature range.

The perspective view which decomposes | disassembles and shows an example of this invention. The principal part enlarged view which shows typically the end surface structure after the assembly of the example shown in FIG. An exploded perspective view showing an example of a conventional through-type current sensor Explanatory drawing of the principal part which expands and shows the cross-sectional structure after the assembly of the example shown in FIG.

  As shown in FIGS. 1 and 2, the annular through-type current sensor 11 includes a fluxgate sensor element 12 and a small-diameter permalloy case 22 as a core material that accommodates the fluxgate sensor elements 12 in a stack. A plurality of one-side permalloy thin pieces 42 laminated to cover the opening 27 of the small-diameter permalloy case 22, and the small-diameter permalloy case 22 from the opening 27 side where the one-side permalloy thin pieces 42 are laminated. A large-diameter permalloy case 32 serving as a core material covering the core, and a plurality of other permalloy flakes 43 stacked between the opening 33 of the large-diameter permalloy case 32 and the bottom wall 23 of the small-diameter permalloy case 22 At least.

  Among these, as the fluxgate sensor element 12 having an annular shape, an element having an appropriate structure including the fluxgate sensor element 2 shown in FIG. Can be adopted.

  The small-diameter permalloy case 22 includes an annular bottom wall 23, an outer peripheral wall 24 erected along the outer peripheral edge 23 a of the bottom wall 23, and an inner peripheral edge 23 b of the bottom wall 23. And an inner peripheral wall portion 25 erected.

  Moreover, the internal space 26 surrounded by the bottom wall portion 23, the outer peripheral wall portion 24, and the inner peripheral wall portion 25 in a substantially U-shaped cross section smoothly accommodates the flux gate sensor elements 12 in two layers from the opening 27 side. The volume which can be formed is provided.

  Further, the small-diameter permalloy case 22 is provided with a single slit 28 extending from a position in the vicinity of the outer peripheral edge 23 a of the bottom wall portion 23 to the open edge 24 a of the outer peripheral wall portion 24, and each flux gate sensor element is provided via the slit 28. The lead wire 12a drawn from 12 can be led out to the outside.

  The one-side permalloy thin piece 42 and the other-side permalloy thin piece 43 each have a width sufficient to close the opening 27 of the small-diameter permalloy case 22 and have a thickness of, for example, about 0.1 mm. It is formed in a ring shape and is arranged by stacking as many as desired.

  In this case, each one-side permalloy thin piece 42 and each other-side permalloy thin piece 43 are not bonded and integrated with each other at the time of stacking arrangement, and each piece is in a separated state. They are simply stacked.

  On the other hand, the large-diameter permalloy case 32 includes an annular bottom wall portion 33, an outer peripheral wall portion 34 erected along the outer peripheral edge 33 a of the bottom wall portion 33, and an inner peripheral edge 33 b of the bottom wall portion 33. It is formed with the inner peripheral wall part 35 standingly arranged along.

  Moreover, the inner space 36 surrounded by the bottom wall portion 33, the outer peripheral wall portion 34, and the inner peripheral wall portion 35 in a substantially U-shaped cross section includes a plurality of one-side permalloy thin pieces 42 arranged in a stacked manner, and the fluxgate sensor element 12. Is formed with a volume that can accommodate the small-diameter permalloy case 22 accommodated in a stack of two sheets and the plurality of stacked other side permalloy thin pieces 43 from the opening 37 side. Has been.

  The large-diameter permalloy case 32 has a single slit 38 extending from a position near the outer peripheral edge 33 a of the bottom wall 33 to the open edge 34 a of the outer peripheral wall 34 at a position facing the slit 28 of the small-diameter permalloy case 22. Therefore, the lead wire 12a of each fluxgate sensor element 12 led out through the slit 28 can be further led out to the outside through the slit 38.

  In the through-type current sensor 11, an insulating tape (not shown) is wound around the peripheral surface 37 including the opening 37 of the large-diameter permalloy case 32, a feedback winding is wound thereon, and a conductive tape such as a copper foil tape is further wound thereon. As a result, the whole is formed under the condition of being wound and electrostatically shielded.

  Next, the operation and effect of the present invention having the above configuration will be described. The small-diameter permalloy case 22 and the large-diameter permalloy case 32 constituting the through-type current sensor 11 are different from those formed of a ferrite material. In either case, since the magnetic permeability is high and it does not crack, the magnetic characteristics can be stabilized by eliminating the adverse effects of the magnetic resistance, and various characteristics as a sensor can be greatly improved.

  In addition, it is said that permalloy used as a material generally has a worse frequency characteristic as the thickness is increased, and a frequency characteristic is improved as the thickness is thinner.

  In the present invention, on the premise of this, the small-diameter permalloy case 22 and the large-diameter permalloy case 32 are formed with a thickness of about 1 mm, for example, and the one-side permalloy thin piece 42 and the other-side permalloy thin piece 43 are, for example, 0 A thin film having a thickness of about 1 mm is used, and a combination of these structures can be used in a wide frequency band. That is, the small-diameter permalloy case 22 and the large-diameter permalloy case 32 are formed with a relatively large thickness, so that they are excellent in strength and in relation to the influence of an external magnetic field. The one-side permalloy flakes 42 and the other-side permalloy flakes 43 are thin, so that leakage flux can be suppressed even at high frequencies and can be used in a wide frequency band as a whole. It will be possible.

  Moreover, normally, when a slit is provided in the core material, the slit becomes a magnetic resistance and is adversely affected by the position of the conductor to be measured. However, the small-diameter permalloy case 22 and the large-diameter permalloy case 32 as the core material in the present invention are provided with the respective slits 28 and 38 on the outer side opposite to the position of the conductor to be measured. Current can be measured without degrading performance.

  Furthermore, unlike the case of using a ferrite material, the small-diameter permalloy case 22 and the large-diameter permalloy case 32 can be formed at low cost by producing a mold.

  In addition, the small-diameter permalloy case 22 and the large-diameter permalloy case 32 can stabilize various characteristics in a wider temperature range as compared with the case of using a ferrite material. It can be suitably commercialized as a through current sensor 11 having a wide adaptive temperature range that can be well adapted to the parts related to automobiles exposed to.

DESCRIPTION OF SYMBOLS 11 Through-type current sensor 12 Flux gate sensor element 12a Lead wire 22 Small diameter permalloy case 23 Bottom wall part 23a Outer peripheral edge 23b Inner peripheral edge 24 Outer peripheral wall part 24a Open edge 25 Inner peripheral wall part 26 Internal space 27 Opening part 28 Slit 32 Large diameter permalloy Case 33 Bottom wall portion 33a Outer peripheral edge 33b Inner peripheral edge 34 Outer peripheral wall part 34a Open edge 35 Inner peripheral wall part 36 Internal space 37 Opening part 38 Slit 39 Peripheral surface 42 One side permalloy thin piece 43 Other side permalloy thin piece

Claims (2)

A fluxgate sensor element having an annular shape, a small-diameter permalloy case that accommodates the fluxgate sensor elements in a stack, and a plurality of one-side permalloy flakes that are stacked to close the opening of the small-diameter permalloy case A large-diameter permalloy case that covers the small-diameter permalloy case containing the fluxgate sensor element together with the one-side permalloy thin piece, and a laminated arrangement between the opening of the large-diameter permalloy case and the bottom wall of the small-diameter permalloy case A through-type current sensor comprising at least a plurality of other permalloy thin pieces. The small-diameter permalloy case and the large-diameter permalloy case are provided with slits for deriving each lead wire drawn out from the fluxgate sensor element 12 accommodated in a two-layered manner at facing positions on the outer peripheral wall side. The through-type current sensor according to claim 1.

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