JP4862625B2 - Non-contact displacement sensor device - Google Patents

Description

  The present invention relates to a non-contact displacement sensor device with high detection accuracy that is not affected even if there is a magnetic substance in the surroundings.

  As a conventional non-contact type displacement sensor device, a device disclosed in Japanese Patent Laid-Open No. 2006-208138 (Patent Document 1) is provided. As shown in FIG. 4A, this non-contact type displacement sensor device 1 has a U-shaped core 2 partially formed with a notch 2A and a base 2B of the core 2 interposed therebetween. When the sensor member 4 including the coil 3 arranged as described above is provided and an alternating current flows through the coil 3, an alternating magnetic field as shown in FIGS. 5 (a) and 5 (b) is formed. 5A is a diagram illustrating the flow of an AC magnetic field when there is a detection target W, and FIG. 5B is a diagram illustrating the flow of an AC magnetic field when there is no detection target W.

On the other hand, the detection target indicated by the symbol W is fixed to the magnetic body 5 of the actuator and moves along the arrow X direction in the notch 2A of the core 2 (FIGS. 4A and 4B). ) And FIG. 5 (c)). When the detection target W is moved in the direction of the arrow X by driving the actuator, the inductance of the coil 3 is changed, and the change of the inductance is measured by a detection circuit (not shown) to thereby detect the arrow of the detection target W. A displacement amount x in the X direction is measured.
JP 2006-208138 A

  By the way, since the non-contact type displacement sensor device 1 as described above is often incorporated in an actuator that moves linearly, as shown in FIG. Depending on the distance between the sensor member 4 and the magnetic body 5 when sandwiched between the magnetic bodies 5 to be fixed, the leakage magnetic flux from the alternating magnetic field also flows into the magnetic body 5 and is generated when the actuator is driven. The magnetic body 5 on the detection target W side may be displaced in the Y direction (vertical direction) due to vibrations that occur, and the entire sensor member 4 may also be displaced in the Y direction. There is a problem that false detection occurs due to change.

  An object of the present invention is to provide a non-contact displacement sensor device with high detection accuracy that is less affected even if there is a magnetic body around it. And

  In order to achieve the above object, the problem-solving means of the present invention is a non-contact displacement sensor device that measures the amount of movement of a detection target by detecting a change in the magnetic field of a coil fixed to a core. The core is composed of a core base and three core standing parts that are erected at a certain interval from the core base and have a detection part through which the detection target passes. Are arranged on the core base so that the central core standing portion is interposed therebetween.

  The problem-solving means of the present invention is a non-contact type displacement sensor device for measuring a movement amount of a detection target by detecting a change in a magnetic field of a coil fixed to the core, wherein the core includes a core base portion. And at least three core standing portions having a detection portion that passes through the core base portion at a predetermined interval and through which the detection target passes, and the coil is disposed on the core base portion. In addition, the core standing portions located in the intermediate portion are disposed so as to be sandwiched therebetween.

  In the problem solving means of the present invention, the core standing portion is provided with a protruding portion that protrudes toward the detection portion through which the detection target passes.

  In the non-contact type displacement sensor device shown in the present invention, the core base portion is provided so that three core standing portions are erected at a certain interval from the core base portion, and the central core standing portion is interposed therebetween. The upper coil detects the displacement of the detection target passing through the two gaps between the core standing parts. That is, in the non-contact type displacement sensor device of the present invention, the magnetic flux from the coil arranged so as to interpose the central core standing portion is divided and then split after passing through the central core standing portion. Because it reaches the two core standing parts on the part side, the leakage magnetic flux can be reduced, and even if there is a magnetic substance around it, the influence of the leakage magnetic flux on the magnetic substance is small. The displacement can be detected with high accuracy.

  Further, in the non-contact type displacement sensor device shown in the present invention, at least three core standing portions are erected at a certain interval on the core base portion, and the core standing portion located at the intermediate portion is interposed therebetween. The displacement of the detection target that passes through the gaps between the plurality of core standing parts is detected by the coil on the core base that is provided as described above. That is, in the non-contact type displacement sensor device of the present invention, after the magnetic flux from the coil arranged so as to interpose the core standing portion located in the intermediate portion passes through the core standing portion of the intermediate portion, Since it is divided and reaches the core standing part on both sides, the leakage magnetic flux can be reduced, and even if there is a magnetic substance around it, the influence of the leakage magnetic flux on the magnetic substance is small. Displacement can be detected with high accuracy.

  In the non-contact type displacement sensor device shown in the present invention, the core standing portion is provided with the protruding portion that protrudes toward the detecting portion through which the detection target passes, so that the magnetic flux flow is guided to the inner protruding portion. The leakage magnetic flux to the outside can be reduced, and also in this respect, the influence of the leakage magnetic flux on the surrounding magnetic body can be reduced, and the displacement of the detection target can be detected with high accuracy.

  A first embodiment according to the present invention will be described below with reference to FIGS. A non-contact type displacement sensor device denoted by reference numeral 10 in FIG. 1A includes a core 11 having a gap portion 11A and formed in a “3” shape as a whole, and a coil disposed so as to sandwich the core 11 therebetween. The sensor member 13 consisting of 12 is provided. The core 11 is composed of a horizontally disposed core base portion 14 and three core standing portions 15 standing on the core base portion 14 at a predetermined interval. The upper position of the gap 11A is a detection unit 16 through which the detection target W passes. The coil 12 is disposed on the core base portion 14 so that the central core standing portion 15 is interposed therebetween. When an alternating current flows through the coil 12, the alternating current as shown by a dotted line in FIG. A magnetic field is formed.

  The detection target W is fixed to a magnetic body (not shown) of the actuator, and moves in a direction perpendicular to the paper surface by the detection unit 16 located above the gap 11A of the core 11. When the detection target W is moved by driving the actuator, the inductance of the coil 12 changes, and the change in the inductance is measured by a detection circuit (not shown) to thereby detect the detection target W in the direction of the arrow X (see FIG. 1 in a direction perpendicular to the paper surface). 1B is a diagram showing the flow of an alternating magnetic field when there is a detection target W, and FIG. 1C is a diagram showing the flow of an alternating magnetic field when there is no detection target W. With reference to these drawings, FIG. As can be seen, when an alternating current flows through the coil 12, the magnetic flux from the coil 12 passes through the central core standing portion 15 and is then divided and positioned on both ends of the core standing portion 15. To.

  In the non-contact type displacement sensor device 10 configured as described above, three core standing portions 15 are erected at a certain interval on the core base portion 14, and the central core standing portion 15 is interposed therebetween. The displacement of the detection target W that passes through the two gap portions 11A between the core standing portions 15 is detected by the coil 12 on the core base portion 14 provided as described above. That is, in the non-contact type displacement sensor device 10 described above, as shown in FIGS. 1B and 1C, the magnetic flux from the coil 12 disposed so as to interpose the central core standing portion 15 is interposed. After passing through the central core standing part 15, it is divided and reaches the core standing part 15 on both sides located on the end side, so that leakage magnetic flux can be reduced and there is a magnetic body around However, the influence of the leakage magnetic flux on the magnetic material is small, so that the displacement of the detection target W can be detected with high accuracy.

  In the first embodiment, as indicated by reference numeral 17 in FIG. 1 (a), a protrusion projecting toward the gap 11A on the upper side of the core standing portion 15 on both sides of the core base portion 14 is provided. Although the portion 17 is provided and the wall surface 15A of the central core standing portion 15 is made smooth, the present invention is not limited to this, and as shown in FIG. Protrusions 17 projecting to the side are provided, or, as shown in FIG. 2B, four projecting parts 17 projecting to the gap 11A side are provided at the top of all three core standing parts 15. Anyway.

  In such a non-contact displacement sensor device 10, the core standing portion 15 is provided with the protrusion 17 that protrudes toward the detection portion 16 through which the detection target W passes, so that the magnetic flux flows on the inner side. The leakage magnetic flux to the outside can be reduced by being guided to the protrusion 17, and also in this respect, the influence of the leakage magnetic flux on the surrounding magnetic body can be reduced, and the displacement of the detection target W can be performed with high accuracy. It becomes possible to detect.

  Next, a second embodiment will be described with reference to FIG. The non-contact type displacement sensor device 20 shown in FIG. 3 is different from the non-contact type displacement sensor device 10 shown in the first embodiment in the configuration of a sensor member 23 including a core 21 and a coil 22. That is, the core 21 of the sensor member 23 is characterized by the number of core standing portions 25 that are erected on the core base portion 24 at a predetermined interval. In this embodiment, the core standing portion 25 is provided. Are installed in two, and two pairs of coils 22 are installed on the core base 24 so as to interpose three core standing portions 25 in the middle portion excluding both ends. In the non-contact displacement sensor device 20, when an AC current flows through the coil 22 and an AC magnetic field as shown by a dotted line in FIG. 3 is formed, the detection target W is driven by the actuator as shown in FIG. When moving in a direction orthogonal to the paper surface and passing through the detection unit 26 positioned above the gap 21A, the inductance of the coil 22 changes, and the change in inductance is measured by a detection circuit (not shown). Thus, the displacement of the detection target W is measured.

  In the non-contact type displacement sensor device 20 configured as described above, the coils are arranged so that the core standing portions 25 (the three core standing portions 25) located in the middle are interposed therebetween. After the magnetic flux from 22 passes through the core standing portion 25 at the intermediate part and is divided to reach the core standing portion 25 on both sides, the leakage magnetic flux can be reduced as in the first embodiment. Even if there is a magnetic body around it, the influence of the leakage magnetic flux on the magnetic body can be reduced, and thereby the displacement of the detection target W can be detected with high accuracy.

  In the non-contact type displacement sensor device 20 described above, all the core standing portions are formed such that the same protrusions 27 as the non-contact type displacement sensor device 10 shown in FIG. 2 protrude toward the gap portion 21A. However, the present invention is not limited to this, and as shown in FIG. 1 or FIG. Further, the number of the core standing portions 25 that are erected on the core base portion 24 at a predetermined interval is at least three, and is not limited to five as shown in the second embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which shows 1st Embodiment concerning this invention, Comprising: (a) is a basic block diagram, (b) is a figure which shows magnetic flux when there exists a detection target, (c) is a case where there is no detection target The figure which shows magnetic flux. It is a front view which shows the modification of 1st Embodiment, (a) is a figure at the time of providing a projection part in the center core standing part, (b) Protrusion part is provided in all the core standing parts. Figure of the case. The front view which shows 2nd Embodiment concerning this invention. It is a figure which shows the conventional non-contact type displacement sensor apparatus, Comprising: (a) Front view, (b) Side sectional view which cut | disconnected Fig.4 (a) along arrow BB. It is a front view which shows the flow of the magnetic flux of the conventional non-contact type displacement sensor apparatus, Comprising: (a) is a figure which shows magnetic flux when there exists a detection target, (b) is a figure which shows magnetic flux when there is no detection target, (C) is a figure which shows magnetic flux when there exists a magnetic body around.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Non-contact displacement sensor apparatus 11 Core 11A Gap part 12 Coil 13 Sensor member 14 Core base 15 Core standing part 16 Detection part 17 Protrusion part 20 Non-contact displacement sensor apparatus 21 Core 21A Gap part 22 Coil 23 Sensor member 24 Core Base 25 Core standing part 26 Detection part 27 Projection part

Claims (3)

A non-contact displacement sensor device that measures the amount of movement of a detection target by detecting a change in the magnetic field of a coil fixed to a core,
The core comprises a core base, and three core standing portions that are provided at a certain interval on the core base and have a detection portion through which the detection target passes in the gap portion,
The said coil is arrange | positioned on a core base part so that a center core standing part may be interposed in between, The non-contact-type displacement sensor apparatus characterized by the above-mentioned. A non-contact displacement sensor device that measures the amount of movement of a detection target by detecting a change in the magnetic field of a coil fixed to a core,
The core comprises a core base, and at least three core standing parts that are provided at a predetermined interval on the core base and have a detection part through which the detection target passes.
The said coil is arrange | positioned so that the core standing part located in an intermediate part may be pinched | interposed on the said core base part, The non-contact-type displacement sensor apparatus characterized by the above-mentioned.   The non-contact type displacement sensor device according to claim 1, wherein the core standing part is provided with a protruding part that protrudes toward a detection part through which the detection target passes.

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