JP2018124168A - Temperature detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature detection device that can improve the accuracy in temperature detection even in an environment where the relative position of a temperature sensitive magnetic substance cannot be accurately fixed.SOLUTION: A temperature detection device 1 comprises: magnetic field generation means 10; a temperature sensitive magnetic substance 13; first and fourth magnetic sensors 15 to 18; and an operation part 20. The first to fourth magnetic sensors 15 to 18 are arranged such that a plurality of measured values can be obtained changing differently from each other for a change in temperature of the temperature sensitive magnetic substance 13 and a change in position in an arbitrary direction of the temperature sensitive magnetic substance 13. The operation part 20 detects the temperature of the temperature sensitive magnetic substance 13 on the basis of the plurality of measured values obtained from the first to fourth magnetic sensors 15 to 18.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temperature detection device using a temperature-sensitive magnetic material.

  As a temperature detection device that detects temperature wirelessly, a temperature-sensitive magnetic body having an arbitrary Curie point is arranged in the measurement target part, and a magnetic field is generated from a magnetic field generation source installed at a location away from the measurement target part. A device that measures the temperature of a measurement target part by detecting a change in a magnetic flux vector of a magnetic field, which depends on the temperature of a temperature-sensitive magnetic body, with a magnetic sensor is known.

Japanese Patent No. 5263894

  In the configuration of Patent Document 1, the magnetic flux vector detected by the magnetic sensor changes due to a temperature change of the measurement target part, but also changes due to a change in the relative position of the temperature-sensitive magnetic body with respect to the magnetic field generation source and the magnetic sensor. For this reason, there has been a problem that accurate temperature measurement cannot be performed unless the relative position of the temperature-sensitive magnetic body can be fixed with high accuracy.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a temperature detection device capable of improving the accuracy of temperature detection even in an environment where the relative position of the temperature-sensitive magnetic body cannot be fixed with high accuracy. Is to provide.

One embodiment of the present invention is a temperature detection device. This temperature detector is
A magnetic field generation means, a temperature-sensitive magnetic body, and a plurality of magnetic sensors;
The plurality of magnetic sensors are arranged to obtain a plurality of measurement values that change differently with respect to a temperature change of the temperature-sensitive magnetic body and a position change of the temperature-sensitive magnetic body in an arbitrary direction,
The temperature of the temperature-sensitive magnetic body is detected based on a plurality of measured values obtained from the plurality of magnetic sensors.

  In the plurality of magnetic sensors, the first condition that distances from virtual lines connecting the magnetic field generation means and the temperature-sensitive magnetic body are the same as each other, and distances from the magnetic field generation means or the temperature-sensitive magnetic body are equal to each other. It may be arranged so as not to satisfy the positional relationship satisfying both of the second condition.

Another aspect of the present invention is a temperature detection device. This temperature detector is
A magnetic field generation means, a temperature-sensitive magnetic body, and a plurality of magnetic sensors;
In the plurality of magnetic sensors, the first condition that distances from virtual lines connecting the magnetic field generation means and the temperature-sensitive magnetic body are the same as each other, and distances from the magnetic field generation means or the temperature-sensitive magnetic body are equal to each other. It is arranged so as not to have a positional relationship that satisfies both the second condition and
The temperature of the temperature-sensitive magnetic body is detected based on a plurality of measured values obtained from the plurality of magnetic sensors.

  The magnetic field generation unit and the plurality of magnetic sensors may not be on the same straight line.

  A plurality of magnetic field generation means may be provided, and the temperature of the thermosensitive magnetic material may be detected based on a plurality of measured values in each case where a magnetic field is generated one by one from the plurality of magnetic field generation means.

  The temperature sensitive magnetic material may be a temperature sensitive ferrite.

  The magnetic field generating means may be a coil.

  The magnetic field generated by the magnetic field generating means may be an alternating current.

  It should be noted that any combination of the above-described constituent elements, and those obtained by converting the expression of the present invention between methods and systems are also effective as aspects of the present invention.

  According to the present invention, it is possible to provide a temperature detection device capable of improving the accuracy of temperature detection even in an environment where the relative position of the temperature-sensitive magnetic body cannot be fixed with high accuracy.

1 is a schematic configuration diagram of a temperature detection device 1 according to Embodiment 1 of the present invention. The graph which shows an example of the relationship (temperature characteristic) of the temperature of the temperature-sensitive magnetic body 13 of FIG. 1, and relative permeability (mu) i. FIG. 6 is a layout explanatory diagram of the magnetic field generation means 10, the temperature-sensitive magnetic body 13, the first magnetic sensor 15, and the second magnetic sensor 16, which are the premise of the simulation results of FIG. 4 and FIG. 4 (A) and 4 (B) show the relative permeability μi and temperature T of the temperature-sensitive magnetic body 13 and the position of the temperature-sensitive magnetic body 13 in the Y direction (displacement amount) in the arrangement of FIG. Table of the output voltage V1 of the first magnetic sensor 15 and the output voltage V2 of the second magnetic sensor 16 specified by the combination of. 5A and 5B show the temperature of the temperature-sensitive magnetic body 13 derived from the output voltage V1 of the first magnetic sensor 15 and the output voltage V2 of the second magnetic sensor 16 in the arrangement of FIG. The graph which plotted the combination of T and the position (position shift | offset | difference amount) of the Y direction of the thermosensitive magnetic body 13 as an isoline. The schematic block diagram of the temperature detection apparatus 2 which concerns on Embodiment 2 of this invention. The schematic block diagram of the temperature detection apparatus 3 which concerns on Embodiment 3 of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent component, member, etc. which are shown by each drawing, and the overlapping description is abbreviate | omitted suitably. In addition, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a temperature detection device 1 according to Embodiment 1 of the present invention. In FIG. 1, XYZ axes that are three orthogonal axes are defined. The temperature detection device 1 includes a magnetic field generation unit 10, a temperature-sensitive magnetic body 13, a first magnetic sensor 15, a second magnetic sensor 16, a third magnetic sensor 17, a fourth magnetic sensor 18, and a calculation unit 20. Here, the magnetic field generating means 10 is an electromagnet (coil). In FIG. 1, an energization circuit for the magnetic field generation means 10 is not shown.

  The temperature-sensitive magnetic body 13 is, for example, a temperature-sensitive ferrite, and is provided inside the detection target (detected portion) 5. The detection object 5 may be a deformable material such as resin or rubber, or may be a liquid such as oil, or may be one or both of the magnetic field generation means 10 and each magnetic sensor and a wall. It may be a partitioned (separated) space. FIG. 2 is a graph showing an example of the relationship (temperature characteristic) between the temperature of the temperature-sensitive magnetic body 13 and the relative permeability μi. The temperature characteristics shown in FIG. 2 are obtained when a magnetic field having a frequency of 1 kHz and an amplitude of 0.4 A / m is applied. In the temperature characteristics shown in FIG. 2, the relative permeability μi rapidly decreases as the temperature rises when the temperature T on the horizontal axis is in the range of 210 ° C. to 230 ° C., and the temperature-sensitive magnetic body 13 is in the temperature range. It can be suitably used for temperature detection. Here, the temperature range in which the relative permeability μi rapidly decreases as the temperature rises varies depending on the material of the temperature-sensitive magnetic body 13, and the material of the temperature-sensitive magnetic body 13 is selected according to the temperature range to be detected. do it. The temperature-sensitive magnetic body 13 can also be used for temperature detection in a temperature range (in the example of FIG. 2, a temperature range of 200 ° C. or lower) in which the relative permeability μi gradually increases as the temperature rises.

  The first magnetic sensor 15, the second magnetic sensor 16, the third magnetic sensor 17, and the fourth magnetic sensor 18 (hereinafter also referred to as “first to fourth magnetic sensors 15 to 18”) each have a predetermined direction (here, Y Direction) magnetic flux density magnitude (scalar value) is measured (detected), and is provided on the opposite side of the magnetic field generation means 10 with the detection target 5 interposed therebetween. The first to fourth magnetic sensors 15 to 18 have a plurality of output voltages (magnetic measurement) that change differently with respect to a temperature change of the temperature-sensitive magnetic body 13 and a position change of the temperature-sensitive magnetic body 13 in an arbitrary direction. Value). Specifically, the first to fourth magnetic sensors 15 to 18 have the first condition that the distances from the virtual straight line L connecting the magnetic field generating means 10 and the temperature-sensitive magnetic body 13 are the same, and the magnetic field generating means 10 or It arrange | positions so that it may not become the positional relationship which satisfy | fills both the 2nd conditions that the distance from the temperature-sensitive magnetic body 13 is mutually equal. The reason is that when both the first and second conditions are satisfied, when the position of the temperature-sensitive magnetic body 13 changes along the imaginary straight line L, the output voltages of the first to fourth magnetic sensors 15 to 18 change. Is the same. Further, the magnetic field generation means 10 and the first to fourth magnetic sensors 15 to 18 do not exist on the same straight line. If they exist in the same straight line, the output voltages of the first to fourth magnetic sensors 15 to 18 do not change when the position of the temperature-sensitive magnetic body 13 changes around the axis about the straight line. is there.

  The computing unit 20 is specified by four combinations of the temperature of the temperature-sensitive magnetic body 13 and the X-direction position, the Y-direction position, and the Z-direction position of the temperature-sensitive magnetic body 13. -18 are stored in advance as a table, and the temperature of the temperature-sensitive magnetic body 13, that is, the temperature of the detection object 5 is detected based on the output voltages of the first to fourth magnetic sensors 15-18 ( Identify. In addition, in FIG. 1, illustration of the connection wiring between the calculating part 20 and the 1st-4th magnetic sensors 15-18 is abbreviate | omitted. The reason why the output voltages (magnetic measurement values) of the four magnetic sensors (first to fourth magnetic sensors 15 to 18) are used to detect the temperature of the temperature-sensitive magnetic body 13 is as follows.

  The output voltages of the first to fourth magnetic sensors 15 to 18 change according to the temperature change of the temperature-sensitive magnetic body 13 (temperature change of the detection target 5), but the magnetic field generating means 10 and the first to fourth magnetic sensors. It changes also with the change of the relative position of the temperature sensitive magnetic body 13 with respect to 15-18. Therefore, assuming that only one of the first to fourth magnetic sensors 15 to 18 is present, the change in the output voltage of the one magnetic sensor under an environment in which the position of the temperature-sensitive magnetic body 13 fluctuates due to vibration or the like. However, it is not possible to specify whether the temperature is due to a temperature change of the temperature-sensitive magnetic body 13 or a change in the relative position of the temperature-sensitive magnetic body 13. The temperature of the object 5 cannot be detected).

  Here, when a change in the relative position of the temperature-sensitive magnetic body 13 occurs three-dimensionally, the temperature, the X-direction position, the Y-direction position, and the Z-direction position of the temperature-sensitive magnetic body 13 are unknown. . For this reason, in this embodiment, the four unknowns (the temperature of the temperature-sensitive magnetic body 13 and the three-dimensional position) are obtained by using the four output voltages obtained from the first to fourth magnetic sensors 15 to 18. And the temperature of the temperature-sensitive magnetic body 13 can be detected. In addition, when the relative position change of the temperature-sensitive magnetic body 13 is two-dimensional, since there are three unknowns, three magnetic sensors are sufficient to detect the temperature of the temperature-sensitive magnetic body 13. Similarly, when the change in the relative position of the temperature-sensitive magnetic body 13 is one-dimensional, since there are two unknowns, two magnetic sensors are sufficient to detect the temperature of the temperature-sensitive magnetic body 13.

  FIG. 3 is an explanatory diagram of the arrangement of the magnetic field generating means 10, the temperature-sensitive magnetic body 13, the first magnetic sensor 15, and the second magnetic sensor 16, which are the premise of the simulation results of FIGS. Here, the principle of specifying the temperature of the temperature-sensitive magnetic body 13 will be described by taking as an example a case where the relative position of the temperature-sensitive magnetic body 13 varies only in the Y direction (the position in the XZ direction is fixed). Since the change in the relative position of the temperature-sensitive magnetic body 13 is one-dimensional, the number of magnetic sensors is two (the first magnetic sensor 15 and the second magnetic sensor 16).

  4 (A) and 4 (B) show the relative permeability μi and temperature T of the temperature-sensitive magnetic body 13 and the position of the temperature-sensitive magnetic body 13 in the Y direction (displacement amount) in the arrangement of FIG. Is a table of the output voltage V1 of the first magnetic sensor 15 and the output voltage V2 of the second magnetic sensor 16 specified by the combination of. Each voltage value in these tables is calculated by simulation and stored in advance in the calculation unit 20 (FIG. 1) as a table. In the simulation, a magnetic field having a frequency of 1 kHz was applied to the first magnetic sensor 15 and the second magnetic sensor 16. The table actually stored is the relative permeability μi and temperature T of the temperature-sensitive magnetic body 13 and the Y direction of the temperature-sensitive magnetic body 13 than those shown in FIGS. 4 (A) and 4 (B). The position (the amount of displacement) and the step size are much finer.

  5A and 5B show the temperature of the temperature-sensitive magnetic body 13 derived from the output voltage V1 of the first magnetic sensor 15 and the output voltage V2 of the second magnetic sensor 16 in the arrangement of FIG. It is the graph which drawn the combination of T and the position (position shift amount) of the thermosensitive magnetic body 13 in the Y direction as an isoline. FIG. 5A shows an isoline when the output voltage V1 of the first magnetic sensor 15 is 106.57 mV, and is drawn based on the table of FIG. FIG. 5B shows an isoline when the output voltage V2 of the second magnetic sensor 16 is 101.24 mV, and is drawn based on the table of FIG. Stars in FIGS. 5A and 5B are attached to points where the isolines shown in FIGS. 5A and 5B intersect. At some point, when the measured value of the output voltage V1 of the first magnetic sensor 15 is 106.57 mV and the output voltage V2 of the second magnetic sensor 16 is 101.24 mV, an intersection with a star (T = 229 ° C and Y = −1.5 mm) is a solution of two unknowns (temperature T of the temperature-sensitive magnetic body 13 and position in the Y direction) at the time point, and the temperature T of the temperature-sensitive magnetic body 13 can be uniquely specified.

  The principle described with reference to FIGS. 3 to 5 is an example in which the change in the relative position of the temperature-sensitive magnetic body 13 is one-dimensional, but the change in the relative position of the temperature-sensitive magnetic body 13 is two-dimensional. Alternatively, even in a three-dimensional case, the temperature of the temperature-sensitive magnetic body 13 can be detected based on the same principle by increasing the number of magnetic sensors to three or four (the temperature T of the temperature-sensitive magnetic body 13 is uniquely set). Can be specified).

  According to the present embodiment, the calculation unit 20 detects the temperature of the temperature-sensitive magnetic body 13 (the temperature of the detection object 5) based on the four measured values obtained from the first to fourth magnetic sensors 15-18. Therefore, even if the relative position of the temperature-sensitive magnetic body 13 changes three-dimensionally, the temperature of the temperature-sensitive magnetic body 13 can be detected with high accuracy. In other words, the accuracy of temperature detection can be improved even in an environment where the relative position of the temperature-sensitive magnetic body 13 cannot be fixed with high accuracy.

(Embodiment 2)
FIG. 6 is a schematic configuration diagram of a temperature detection device 2 according to Embodiment 2 of the present invention. The temperature detection device 2 according to the present embodiment is different from that according to the first embodiment in that a magnetic field generation unit 11 is added, and is identical in other points. The magnetic field generation means 11 is an electromagnet (coil) and is provided on the same side as the magnetic field generation means 10 with respect to the detection target 5. In the temperature detection device 2, a magnetic field is generated from the magnetic field generation unit 10, a first state where no magnetic field is generated from the magnetic field generation unit 11, and a magnetic field is generated from the magnetic field generation unit 11 without generating a magnetic field from the magnetic field generation unit 10. In each of the second states to be performed, the calculation unit 20 detects the temperature of the temperature-sensitive magnetic body 13 based on the four measurement values obtained from the first to fourth magnetic sensors 15 to 18. Thereby, the accuracy of temperature detection can be further improved. The magnetic field generation means 11 may be provided on the same side as the first to fourth magnetic sensors 15 to 18 with respect to the detection target 5.

(Embodiment 3)
FIG. 7 is a schematic configuration diagram of a temperature detection device 3 according to Embodiment 3 of the present invention. In the temperature detection device 3 according to the present embodiment, the magnetic field generation unit 10 has the first to fourth magnetic sensors 15 to 18 and the arithmetic unit 20 with respect to the detection target 5 as compared with the first embodiment. It differs in that it is located on the same side, and it matches in other points. The present embodiment can achieve the same effects as those of the first embodiment.

  The present invention has been described above by taking the embodiment as an example. However, it is understood by those skilled in the art that various modifications can be made to each component and each processing process of the embodiment within the scope of the claims. By the way. Hereinafter, modifications will be described.

  The magnetic field generating means 10 may be a permanent magnet. In this case, the magnetic field generated by the magnetic field generation means 10 is limited to DC, but in principle, temperature detection is possible. The temperature-sensitive magnetic body 13 is not limited to ferrite but may be other magnetic bodies such as a silicon steel plate. The first to fourth magnetic sensors 15 to 18 may be direction detection types that detect the direction of the magnetic flux density applied to the first to fourth magnetic sensors 15 to 18.

1-3 Temperature detector, 5 Object to be detected (detected part), 10, 11 Magnetic field generating means, 13 Temperature-sensitive magnetic body, 15 First magnetic sensor, 16 Second magnetic sensor, 17 Third magnetic sensor, 18 4 magnetic sensors, 20 computing units

Claims (8)

A magnetic field generation means, a temperature-sensitive magnetic body, and a plurality of magnetic sensors;
The plurality of magnetic sensors are arranged to obtain a plurality of measurement values that change differently with respect to a temperature change of the temperature-sensitive magnetic body and a position change of the temperature-sensitive magnetic body in an arbitrary direction,
A temperature detection device that detects the temperature of the temperature-sensitive magnetic body based on a plurality of measurement values obtained from the plurality of magnetic sensors.   In the plurality of magnetic sensors, the first condition that distances from virtual lines connecting the magnetic field generation means and the temperature-sensitive magnetic body are the same as each other, and distances from the magnetic field generation means or the temperature-sensitive magnetic body are equal to each other. The temperature detection device according to claim 1, wherein the temperature detection device is arranged so as not to satisfy a positional relationship satisfying both of the second condition. A magnetic field generation means, a temperature-sensitive magnetic body, and a plurality of magnetic sensors;
In the plurality of magnetic sensors, the first condition that distances from virtual lines connecting the magnetic field generation means and the temperature-sensitive magnetic body are the same as each other, and distances from the magnetic field generation means or the temperature-sensitive magnetic body are equal to each other. It is arranged so as not to have a positional relationship that satisfies both the second condition and
A temperature detection device that detects the temperature of the temperature-sensitive magnetic body based on a plurality of measurement values obtained from the plurality of magnetic sensors.   The temperature detection device according to any one of claims 1 to 3, wherein the magnetic field generation unit and the plurality of magnetic sensors do not exist on the same straight line.   2. The apparatus according to claim 1, further comprising a plurality of magnetic field generation units, wherein the temperature of the thermosensitive magnetic body is detected based on a plurality of measured values in each case where a magnetic field is generated one by one from the plurality of magnetic field generation units. The temperature detection device according to any one of 4.   The temperature detection device according to claim 1, wherein the temperature-sensitive magnetic body is a temperature-sensitive ferrite.   The temperature detection device according to any one of claims 1 to 6, wherein the magnetic field generation means is a coil.   The temperature detection apparatus according to any one of claims 1 to 7, wherein the magnetic field generated by the magnetic field generation means is alternating current.

Images