JPWO2015194316A1 - Displacement detector - Google Patents

Abstract

Displacement detection apparatus that suppresses the influence of temperature-dependent characteristics of a magnetic detection element and improves sensitivity to a measurement object is provided. The displacement detection device is arranged with a gap, a pair of magnets 4 that form a magnetic field in the gap, a soft magnetic body 3 that is arranged between the pair of magnets 4 and is connected to the measuring object 5 and is displaced, A sensor 2 that is disposed between a pair of magnets 4 and that detects a change in a magnetic field based on the displacement of the soft magnetic body 3. The soft magnetic body 3 has a magnetic flux density detected by the sensor 2 in one detection direction. Displacement within a range including a displacement position where becomes zero.

Description

  The present invention relates to a displacement detection device.

  As a conventional technique, there has been proposed a displacement detection device that detects a magnetic flux density between two magnets by a magnetic detection element and detects a position of a soft magnetic material that attracts the magnetic flux between the two magnets (for example, , See Patent Document 1).

  The displacement detection device disclosed in Patent Document 1 is an MR element that is a magnetic detection element that is arranged so that a detection direction is aligned with a direction of magnetic flux generated between two magnets, and a soft that induces magnetic flux generated between the two magnets. The position of the soft magnetic material is detected by utilizing the characteristic that the magnetic flux density transmitted through the MR element decreases when the soft magnetic material is brought close to the MR element.

International Publication No. 2006/035342

  However, the displacement detection device shown in Patent Document 1 detects a magnetic flux density of 0 because the magnetic flux density that passes through the MR element is always positive and the detected magnetic flux density is not zero. Compared to the above, there is a problem that the temperature dependence characteristic per displacement amount of the same soft magnetic material becomes remarkable and the accuracy is inferior. In addition, it is necessary to increase the size of the soft magnetic material in order to attract the magnetic flux, and as a result, the weight of the soft magnetic material increases, resulting in a problem that the sensitivity to the displacement of the measurement object connected to the soft magnetic material is reduced. It was. Further, since the magnetic flux passing through the soft magnetic material fluctuates, there is a problem that hysteresis occurs when the magnetic element is moved closer to and away from the MR element.

  Accordingly, an object of the present invention is to provide a displacement detection device that suppresses the influence of the temperature-dependent characteristics of a magnetic detection element and improves the sensitivity to a measurement object.

  One embodiment of the present invention provides the following displacement detection device in order to achieve the above object.

[1] A soft magnetic material that is connected to a measurement object and is displaced;
A magnet that forms a magnetic field in a space that is a movable range of the soft magnetic material;
The magnet is disposed in the space that forms a magnetic field, and has a sensor that detects a change in the magnetic field based on the displacement of the soft magnetic body,
The soft magnetic body is a displacement detection device that is displaced within a range including a displacement position where the magnetic flux density detected by the sensor in one detection direction is zero.
[2] The displacement detection device according to claim 1, wherein the sensor detects a change in the magnetic field in each of a plurality of detection directions, and obtains one output from the plurality of detection results.
[3] The displacement detection device according to claim 1 or 2, wherein the soft magnetic body is displaced within a range in which the transmitted magnetic flux does not change.

According to the invention which concerns on Claim 1, the influence of the temperature dependence characteristic of a magnetic detection element can be suppressed, and the sensitivity with respect to a measuring object can be improved.
According to the invention which concerns on Claim 2, a displacement can be detected from the change of the magnetic field in a some detection direction.
According to the invention which concerns on Claim 3, the influence of the hysteresis which arises in a soft magnetic body can be suppressed.

FIG. 1 is a partial cross-sectional view illustrating a configuration example of a displacement detection device according to the first embodiment. FIG. 2A is a schematic diagram for explaining the operation of the displacement detection device. FIG. 2B is a schematic diagram for explaining the operation of the displacement detection device. FIG. 2C is a schematic diagram for explaining the operation of the displacement detection device. FIG. 3 is a graph showing the relationship between the displacement of the soft magnetic material and the magnetic flux density detected by the sensor. FIG. 4 is a perspective view illustrating a configuration example of a displacement detection device according to the second embodiment. FIG. 5A is a graph showing the relationship between the displacement of the soft magnetic material and the magnetic flux density detected by the sensor. FIG. 5B is a graph showing the relationship between the displacement angle of the soft magnetic material and the output of the sensor. FIG. 5C is a graph showing the relationship between the displacement of the soft magnetic material and the output of the sensor. FIG. 6 is a perspective view illustrating a configuration example of a displacement detection device according to the third embodiment. FIG. 7A is a graph showing the relationship between the displacement of the soft magnetic material and the magnetic flux density detected by the sensor. FIG. 7B is a graph showing the relationship between the angle of displacement of the soft magnetic material and the output of the sensor. FIG. 7C is a graph showing the relationship between the displacement of the soft magnetic material and the output of the sensor. FIG. 8 is a perspective view showing a configuration example of a displacement detection device according to the fourth embodiment. FIG. 9 is a graph showing the relationship between the displacement of the soft magnetic material and the magnetic flux density detected by the sensor. FIG. 10 is a perspective view illustrating a configuration example of a displacement detection device according to the fifth embodiment. FIG. 11 is a perspective view illustrating a configuration example of a displacement detection device according to the sixth embodiment. FIG. 12 is a graph showing the relationship between the displacement of the soft magnetic material and the magnetic flux density detected by the sensor. FIG. 13 is a perspective view showing a configuration example of a displacement detection device according to the seventh embodiment. FIG. 14 is a perspective view showing a configuration example of a displacement detection device according to the eighth embodiment. FIG. 15 is a graph showing the relationship between the displacement of the soft magnetic material and the magnetic flux density detected by the sensor. FIG. 16A is a front view and a perspective view showing a configuration example of a displacement detection device according to the ninth embodiment. FIG. 16B is a front view and a perspective view illustrating a configuration example of a displacement detection device according to the ninth embodiment. FIG. 17A is a perspective view showing a modification of the shape of the soft magnetic material. FIG. 17B is a perspective view showing a modification of the shape of the soft magnetic material. FIG. 17C is a perspective view showing a modification of the shape of the soft magnetic material. FIG. 18A is a perspective view showing a configuration example of a displacement detection device according to the tenth embodiment. FIG. 18B is a front view showing a configuration example of the displacement detection apparatus according to the tenth embodiment. FIG. 18C is a partial cross-sectional view illustrating a configuration example of the displacement detection device according to the tenth embodiment.

[First Embodiment]
(Configuration of displacement detector)
FIG. 1 is a partial cross-sectional view illustrating a configuration example of a displacement detection device according to the first embodiment.

  The displacement detection device 1 includes a sensor 2 that detects a change in magnetic flux density in the detection direction Dsx, a soft magnetic body 3 that is connected to the spring 6 and the connecting member 51 and is displaced in a displacement direction Dd parallel to the detection direction Dsx, and detection. It has a pair of magnets 4 magnetized in the magnetization direction Dm perpendicular to the direction Dsx, and a measuring object 5 that is an object for measuring the displacement of the rubber membrane 50 due to the internal pressure p. In FIG. 1, the vertical direction is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  As an example, the sensor 2 is a Hall IC having a plate shape having a thickness in the x direction, a detection surface parallel to the yz plane, and a Hall element having a detection direction Dsx as a magnetic detection element. Arranged between the magnets 4. The magnetic detection element may be an MR element if the detection direction is Dsx, or a multi-axis magnetic detection IC in which the magnetic detection elements are arranged in a plurality of axial directions including the detection direction Dsx may be used. . The sensor 2 may have an arithmetic circuit in addition to the magnetic detection element.

  The soft magnetic body 3 is a flat plate using a soft magnetic material such as iron having a thickness in the x direction. The soft magnetic body 3 is disposed between the pair of magnets 4 and the magnetic flux attracted by the soft magnetic body 3 is the sensor 2. It shall be displaced within the range that can be detected.

  Further, when the internal pressure p of the measuring object 5 increases and the rubber membrane 50 is deformed, the soft magnetic body 3 is displaced in the x direction via the connection member 51 along with this deformation. It is assumed that the displacement is a minute displacement of about several mm.

  The sensor 2 and the soft magnetic body 3 have the same thickness center in the x direction when the rubber membrane 50 is not deformed (hereinafter referred to as “normal state”), and are closest to each other. In addition, the thickness center in the x direction may be matched except in the normal state.

  The pair of magnets 4 is a permanent magnet formed using a material such as ferrite, samarium cobalt, or neodymium, and forms a uniform magnetic field at least in a space that is a movable range of the soft magnetic body 3. It is assumed that the magnetic flux to be attracted does not fluctuate positively or negatively or does not change so much that the influence of hysteresis is exerted. As an example, the change width of the magnetic flux density attracted by the soft magnetic body 3 is about ± 10 mT.

  The measurement target 5 is, for example, a vehicle throttle valve or the like, and is a target whose air pressure is measured. The measurement object 5 is not limited to the internal pressure p, and any type of displacement can be used as long as a slight displacement occurs and the displacement can be transmitted to the soft magnetic body 3 via the connection member 51. .

  The spring length and the spring constant of the spring 6 are selected so as to balance the force applied to the soft magnetic body 3 by the pressure p of the measurement object 5 in the normal state. If no reaction force is required, the spring 6 may be omitted.

(Operation of displacement detector)
Next, the operation of the first embodiment will be described with reference to FIGS.

  2A to 2C are schematic diagrams for explaining the operation of the displacement detection device 1.

  As shown in FIG. 2A, in the normal state, the sensor 2 and the soft magnetic body 3 have the same x coordinate at the thickness center in the x direction and are closest to each other. In this state, the magnetic flux density in the detection direction Dsx out of the magnetic flux density B penetrating the detection surface of the sensor 2 is Bx = 0. That is, B = Bz.

  Next, when the internal pressure p of the measuring object 5 increases and the rubber membrane 50 is deformed, this deformation is transmitted to the soft magnetic body 3 through the connection member 51, and as shown in FIGS. 2B and 2C, the x direction As d1 and d2 increase in the negative direction, the magnetic flux density Bx in the detection direction Dsx of the magnetic flux density B penetrating the detection surface of the sensor 2 increases in the negative direction. 2B and 2C show the case where the soft magnetic body 3 is displaced in the negative x direction. When the soft magnetic body 3 is displaced in the positive direction, the magnetic flux density Bx increases as the displacement increases. Increase in the direction of. The relationship between the displacement of these soft magnetic bodies 3 and the magnetic flux density detected by the sensor 2 is expressed as shown in FIG. 3 described below.

  FIG. 3 is a graph showing the relationship between the displacement of the soft magnetic body 3 and the magnetic flux density detected by the sensor 2.

  As described above, the relationship between the displacement of the soft magnetic body 3 and the magnetic flux density detected by the sensor 2 has a linear characteristic when the displacement is near zero. As an example, the distance between the magnets 4 is 10 mm, the maximum value of the magnetic flux density detected by the sensor 2 is 20 mT, the minimum value is −20 mT, the shortest distance between the sensor 2 and the soft magnetic body 3 is 0.5 mm, Under the condition that the thickness is 1 mm, linear characteristics are obtained in the range of displacement of ± 1.0 mm, and the range of this variation can be used as the range of use of the displacement detector 1.

(Effects of the first embodiment)
According to the first embodiment described above, since there is a position of the soft magnetic body 3 where the magnetic flux density detected by the sensor 2 becomes zero, the displacement of the soft magnetic body 3 and the magnetic flux density detected by the sensor 2 are Becomes a linear characteristic.

  Further, the temperature dependence characteristics of the magnetic detection element of the sensor 2 become more prominent and less accurate as the detected magnetic flux density increases. However, since the range of the magnetic flux density detected by the sensor 2 is near 0, the temperature dependence characteristics are improved. The accuracy can be improved as compared with the case where the magnetic flux density range is not near zero.

  Further, since it is not necessary to attract a large amount of magnetic flux, it is not necessary to increase the size of the soft magnetic body 3, and as a result, an increase in the weight of the soft magnetic body can be suppressed, and the soft magnetic body is connected due to the increase in weight. A decrease in sensitivity to the displacement of the measurement object can be suppressed.

  In addition, since the magnetic field between the magnets 4 is made uniform and the magnetic flux transmitted through the soft magnetic material is not greatly changed, the influence of hysteresis generated in the soft magnetic material is small, and the configuration of the first embodiment is adopted. Compared with the case where it does not, the fall of precision can be suppressed.

[Second Embodiment]
FIG. 4 is a perspective view illustrating a configuration example of a displacement detection device according to the second embodiment.

  The second embodiment differs from the first embodiment in that the detection direction of the sensor 20 is two directions, the x direction and the z direction. Although the measurement object 5 and the spring 6 are not shown, they are connected so that the displacement direction Dd of the soft magnetic body 3 is the displacement direction Ddx, which is the x direction, as in the first embodiment. And

  The displacement detection device 10 includes a sensor 20 that detects a change in magnetic flux density in the detection directions Dsx and Dsz, a soft magnetic body 3 that is connected to the spring 6 and the connection member 51 and is displaced in the displacement direction Dd, and a magnetization direction Dm. And a pair of magnets 4 magnetized. In FIG. 4, the vertical direction is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The sensor 20 has not only a magnetic detection element but also an arithmetic circuit, and uses a signal obtained by calculating a detection signal of the magnetic detection element as an output signal, as will be described later.

(Operation of displacement detector)
Next, the operation of the second embodiment will be described with reference to FIGS. 4, 5, and 2A to 2C. 2A to 2C, the sensor 2 is replaced with the sensor 20.

  As shown in FIG. 2A, in the normal state, the sensor 20 and the soft magnetic body 3 have the thickness centers in the x direction that coincide with each other in the x coordinate and are closest to each other. In this state, the magnetic flux density in the detection direction Dsx out of the magnetic flux density B penetrating the detection surface of the sensor 20 is Bx = 0. The magnetic flux density in the detection direction Dsz is B = Bz and takes the maximum value.

  Next, as shown in FIGS. 2B and 2C, the magnetic flux density Bx in the detection direction Dsx out of the magnetic flux density B penetrating the detection surface of the sensor 20 as d1 and d2 increase in the negative direction of the x direction. As it increases in the negative direction, the magnetic flux density Bz in the detection direction Dsz decreases. 2B and 2C show the case where the soft magnetic body 3 is displaced in the negative x direction. When the soft magnetic body 3 is displaced in the positive direction, the magnetic flux density Bx increases as the displacement increases. As the magnetic flux density Bz increases, the magnetic flux density Bz decreases. The relationship between the displacement of these soft magnetic bodies 3 and the magnetic flux density detected by the sensor 20 is expressed as shown in FIG.

  FIG. 5A is a graph showing the relationship between the displacement of the soft magnetic body 3 and the magnetic flux density detected by the sensor 20. FIG. 5B is a graph showing the relationship between the displacement angle of the soft magnetic material and the output of the sensor. FIG. 5C is a graph showing the relationship between the displacement of the soft magnetic material and the output of the sensor.

  As shown in FIG. 5A, the relationship between the displacement of the soft magnetic body 3 and the magnetic flux density detected by the sensor 20 is linear in the vicinity of the displacement of 0 in the detection direction Dsx, and the displacement is 0 in the detection direction Dsz. The magnetic flux density decreases as the absolute value of the displacement increases.

  Here, if the angle of the magnetic flux density B with respect to the x-axis is α, arctan (Bz / Bx) = α. The output voltage Vout (α) of the sensor 20 with respect to the angle α is output linearly as shown in FIG. 5B.

  On the other hand, regarding the positional relationship between the sensor 20 and the soft magnetic body 3, when the distance in the z direction between the sensor 20 and the soft magnetic body 3 is dz as shown in FIGS. 2A to 2C, dz is the displacement of the soft magnetic body. Regardless, as shown in FIG. 5C, the relationship of the output voltage Vout (α) of the sensor 20 to the displacement x is the same as the relationship of the output voltage Vout (α) of the sensor 20 to the angle α shown in FIG. 5B. .

(Effect of the second embodiment)
According to the second embodiment described above, in addition to the effects of the first embodiment, the angle α is obtained by calculation using the ratio of the magnetic flux densities Bx and Bz detected by different magnetic detection elements. Therefore, the influence of the temperature dependency characteristic of the magnetic detection element can be canceled, and the detection accuracy of the entire sensor 20 is improved as compared with the case where the influence of the temperature dependency characteristic is exerted.

[Third Embodiment]
FIG. 6 is a perspective view illustrating a configuration example of a displacement detection device according to the third embodiment.

  The third embodiment is different from the first embodiment in that the detection direction of the sensor is the three directions of the x direction, the y direction, and the z direction. Further, the soft magnetic material is different from the first embodiment in that the shape of the soft magnetic material is spherical. The measurement object 5 (not shown) is connected so that the displacement direction of the soft magnetic body 3 is Ddx and Ddy, that is, the x direction and the y direction.

  The displacement detection device 11 is a disk-shaped sensor 21 that detects a change in magnetic flux density in the detection directions Dsx, Dsy, and Dsz, a soft magnetic body 30 that is connected to the connection member 51 and is displaced in the displacement directions Ddx and Ddy. And a pair of magnets 40 magnetized in the magnetization direction Dm. Note that the vertical direction in FIG. 6 is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The soft magnetic body 30 and the magnet 40 are formed with the z axis as the center, and the sensor 21 is arranged on the z axis so that the center thereof is aligned. Therefore, the magnetic flux density detected by the displacement direction Ddx. The change and the change in magnetic flux density detected by the displacement direction Ddy are the same.

(Operation of displacement detector)
Next, the operation of the third embodiment will be described with reference to FIGS.

  In the normal state, the center of the sensor 21 and the soft magnetic body 30 are closest to each other. In this state, the magnetic flux density in the detection direction Dsx (Dsy) out of the magnetic flux density B penetrating the detection surface of the sensor 21 is Bx = 0 (By = 0). The magnetic flux density in the detection direction Dsz is B = Bz and takes the maximum value.

  Next, as the amount of displacement increases in the negative direction of the x direction (y direction), the magnetic flux density Bx (By) in the detection direction Dsx (Dsy) of the magnetic flux density B that penetrates the detection surface of the sensor 21 becomes negative. As it increases, the magnetic flux density Bz in the detection direction Dsz decreases. When the soft magnetic body 3 is displaced in the positive direction in the x direction (y direction), the magnetic flux density Bx (By) increases in the positive direction and the magnetic flux density Bz decreases as the amount of displacement increases. The relationship between the displacement of these soft magnetic bodies 3 and the magnetic flux density detected by the sensor 2 is expressed as shown in FIG.

  FIG. 7A is a graph showing the relationship between the displacement of the soft magnetic body 30 and the magnetic flux density detected by the sensor 21. FIG. 7B is a graph showing the relationship between the angle of displacement of the soft magnetic material and the output of the sensor. FIG. 7C is a graph showing the relationship between the displacement of the soft magnetic material and the output of the sensor.

  As shown in FIG. 7A, the relationship between the displacement of the soft magnetic body 30 and the magnetic flux density detected by the sensor 21 is linear in the vicinity of the displacement of 0 in the detection direction Dsx (Dsy), and in the detection direction Dsz. The maximum value is obtained when the displacement is 0, and the magnetic flux density decreases as the absolute value of the displacement increases.

である。角度αに対するセンサ２０の出力電圧Ｖｏｕｔ（α）が、図７Ｂに示すように、リニアに出力される。なお、角度βに対するセンサ２０の出力電圧Ｖｏｕｔ（β）も同様にリニアに出力される。Here, if the angle of the magnetic flux density B with respect to the x-axis (y-axis) is α (β),

It is. The output voltage Vout (α) of the sensor 20 with respect to the angle α is output linearly as shown in FIG. 7B. Similarly, the output voltage Vout (β) of the sensor 20 with respect to the angle β is also linearly output.

  When the displacement y is 0, as shown in FIG. 7C, the relationship between the output voltage Vout (α) of the sensor 20 and the displacement x is the angle shown in FIG. 7B, as described in the second embodiment. This is the same as the relationship of the output voltage Vout (α) of the sensor 20 with respect to α.

(Effect of the third embodiment)
According to the third embodiment described above, in addition to the effects of the second embodiment, the displacement in the x direction and the y direction can be detected.

[Fourth Embodiment]
FIG. 8 is a perspective view showing a configuration example of a displacement detection device according to the fourth embodiment.

  The fourth embodiment differs from the first embodiment in the shape and arrangement of the magnets and the shape of the soft magnetic material. Although illustration of the measurement object 5 is omitted, unlike the first embodiment, the measurement object 5 is connected so as to rotate the soft magnetic body 31 in the angular direction Ddθ.

  The displacement detection device 12 includes a sensor 22 that detects a change in magnetic flux density in the detection direction Dsx, a soft magnetic body 31 that rotates in the angular direction Ddθ, and a pair of magnets 41a and 41b that are magnetized in the magnetization direction Dm. Have. In FIG. 8, the vertical direction is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The soft magnetic body 31 is provided on the outer peripheral surface of the ring-shaped magnet 41b, and is formed in a spiral shape so that the x-coordinate of the portion closest to the sensor 22 changes as the magnet 41b rotates in the angular direction Ddθ. .

(Operation of displacement detector)
Next, the operation of the fourth embodiment will be described with reference to FIGS.

  In the state where θ = 0, the sensor 22 is assumed to have the x-coordinate of the closest portion of the soft magnetic body 31 and the center in the x-direction. In this state, the magnetic flux density in the detection direction Dsx out of the magnetic flux density B penetrating the detection surface of the sensor 20 is Bx = 0.

  Next, as the x-coordinate of the closest part of the soft magnetic body 31 increases as it rotates in the angular direction Ddθ, the magnetic flux density Bx in the detection direction Dsx out of the magnetic flux density B that penetrates the detection surface of the sensor 22 increases. The relationship between the rotation angle of these soft magnetic bodies 31 and the magnetic flux density detected by the sensor 22 is expressed as shown in FIG. 9 described below.

  FIG. 9 is a graph showing the relationship between the displacement of the soft magnetic body 31 and the magnetic flux density detected by the sensor 22.

  As shown in FIG. 9, the relationship between the rotation angle of the soft magnetic body 31 and the magnetic flux density detected by the sensor 22 is a linear characteristic.

(Effect of the fourth embodiment)
According to the fourth embodiment described above, in addition to the effects of the first embodiment, the displacement angle in the rotation direction can be detected.

[Fifth Embodiment]
FIG. 10 is a perspective view illustrating a configuration example of a displacement detection device according to the fifth embodiment.

  The fifth embodiment is different from the first embodiment in that the detection direction of the sensor is two directions, the x direction and the y direction. The soft magnetic body is different from the first embodiment in that the shape of the soft magnetic body is a ring shape. Note that the measurement object 5 (not shown) is connected so that the displacement direction of the soft magnetic body 32 is Ddx and Ddy, that is, the x direction and the y direction.

  The displacement detection device 13 includes a sensor 23 that detects a change in magnetic flux density in the detection directions Dsx and Dsy, a soft magnetic body 32 that is connected to the connection member 51 and is displaced in the displacement directions Ddx and Ddy, and a disc-like shape. A pair of magnets 40 magnetized in the magnetic direction Dm. 10, the vertical direction is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The soft magnetic body 32 and the magnet 40 are formed with the z axis as the center, and the sensor 23 is arranged on the z axis so that the center thereof is aligned. Therefore, the magnetic flux density detected by the displacement direction Ddx. The change and the change in magnetic flux density detected by the displacement direction Ddy are the same.

(Operation of displacement detector)
Next, the operation of the fifth embodiment will be described with reference to FIGS.

  In the normal state, the center of the sensor 23 and the soft magnetic body 32 in the xy plane is closest to each other. In this state, the magnetic flux density in the detection direction Dsx (Dsy) among the magnetic flux density B penetrating the detection surface of the sensor 23 is Bx = 0 (By = 0).

  Next, as the amount of displacement increases in the x direction (y direction), the magnetic flux density Bx (By) in the detection direction Dsx (Dsy) of the magnetic flux density B that penetrates the detection surface of the sensor 23 increases in the negative direction. In addition, when the soft magnetic body 32 is displaced in the negative direction of the x direction (y direction), the magnetic flux density Bx (By) increases in the positive direction as the displacement amount increases. The relationship between the displacement of these soft magnetic bodies 32 and the magnetic flux density detected by the sensor 23 is expressed as shown in FIG.

  FIG. 12 is a graph showing the relationship between the displacement of the soft magnetic body 32 and the magnetic flux density detected by the sensor 23.

  As shown in FIG. 12, the relationship between the displacement of the soft magnetic body 32 and the magnetic flux density detected by the sensor 23 has a linear characteristic when the displacement is near 0 in the detection direction Dsx (Dsy).

(Effect of 5th Embodiment)
According to the fifth embodiment described above, the same effects as in the third embodiment can be obtained.

[Sixth Embodiment]
FIG. 11 is a perspective view illustrating a configuration example of a displacement detection device according to the sixth embodiment.

  In the sixth embodiment, the detection direction of the sensor of the fifth embodiment and the displacement direction of the soft magnetic material are only in the x direction.

  The displacement detection device 14 includes a sensor 24 that detects a change in magnetic flux density in the detection direction Dsx, a soft magnetic body 33 that is connected to the connection member 51 and is displaced in the displacement direction Ddx, and a pair magnetized in the magnetization direction Dm. Magnet 4. Note that the vertical direction in FIG. 11 is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The soft magnetic body 33 is displaced in the displacement direction Ddx while keeping the distance between the pair of soft magnetic bodies constant.

(Operation of displacement detector)
Next, the effect | action of 6th Embodiment is demonstrated using FIG.11 and FIG.12.

  In the normal state, the center of the sensor 24 and the soft magnetic body 33 on the x axis is closest to each other. In this state, the magnetic flux density in the detection direction Dsx out of the magnetic flux density B penetrating the detection surface of the sensor 24 is Bx = 0.

  Next, as the amount of displacement increases in the x direction, the magnetic flux density Bx in the detection direction Dsx of the magnetic flux density B that penetrates the detection surface of the sensor 24 increases in the negative direction. Further, when the soft magnetic body 33 is displaced in the negative x direction, the magnetic flux density Bx increases in the positive direction as the amount of displacement increases. The relationship between the displacement of these soft magnetic bodies 33 and the magnetic flux density detected by the sensor 24 is expressed as shown in FIG.

(Effect of 6th Embodiment)
According to the sixth embodiment described above, the same effects as in the first embodiment can be obtained.

[Seventh Embodiment]
FIG. 13 is a perspective view showing a configuration example of a displacement detection device according to the seventh embodiment.

  In the seventh embodiment, the coil 7 is provided in the column portion 34 a of the support 34 that supports the soft magnetic body 33, and the displacement of the support 34 is controlled by controlling the current flowing through the coil 7. Is. In addition, although illustration of the measuring object 5 and the spring 6 is omitted, it is assumed that the displacement direction Ddz of the support body 34 including the soft magnetic body 33 is connected in the z direction.

  The displacement detection device 14 includes a sensor 25 that detects a change in magnetic flux density in the detection direction Dsz, a soft magnetic body 33 that is displaced in the displacement direction Ddz, a flat plate magnet 41a and a ring shape that are magnetized in the magnetization direction Dm. Magnet 41b. Note that the vertical direction in FIG. 13 is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The column portion 34a of the support 34 is provided so as to penetrate the center of the ring-shaped magnet 41b, and has the coil 7 on the outer peripheral portion thereof.

  The sensor 25 is connected to a control circuit (not shown), and the control circuit monitors the output voltage of the sensor 25. Further, the coil 7 is connected to a control circuit, and the control circuit controls the current flowing through the coil 7 based on the output voltage of the sensor 25.

(Operation of displacement detector)
Next, the operation of the seventh embodiment will be described with reference to FIGS.

  In the normal state, the sensor 25 and the soft magnetic body 33 are closest to each other in the thickness center in the z direction. In this state, the magnetic flux density in the detection direction Dsz out of the magnetic flux density B penetrating the detection surface of the sensor 25 is Bz = 0.

  Next, as the amount of displacement increases in the z direction, the magnetic flux density Bz in the detection direction Dsz of the magnetic flux density B penetrating the detection surface of the sensor 25 increases. Further, when the displacement is in the negative direction, the magnetic flux density Bz increases in the negative direction as the amount of displacement increases. The relationship between the displacement of these soft magnetic bodies 33 and the magnetic flux density detected by the sensor 25 is expressed as shown in FIG. 15 described below.

  FIG. 15 is a graph showing the relationship between the displacement of the soft magnetic body 33 and the magnetic flux density detected by the sensor 25.

  As shown in FIG. 15, the relationship between the displacement of the soft magnetic body 33 and the magnetic flux density detected by the sensor 25 has a linear characteristic when the displacement is near zero.

  As described above, the sensor 25 detects the magnetic flux density according to the displacement of the soft magnetic body 33 and outputs a signal according to the detected magnetic flux density. The control circuit monitors the output voltage of the sensor 25, calculates the displacement of the soft magnetic body 33 based on the output voltage, and passes a current value corresponding to the calculated displacement to the coil 7. For example, the control circuit may cause a current to flow through the coil 7 so that the displacement of the soft magnetic body 33 becomes zero, or may make the displacement of the soft magnetic body 33 a constant multiple.

(Effect of 7th Embodiment)
According to the seventh embodiment described above, in addition to the effects of the first embodiment, control such as suppressing or amplifying the displacement based on the detected displacement can be performed.

[Eighth Embodiment]
FIG. 14 is a perspective view showing a configuration example of a displacement detection device according to the eighth embodiment.

  In the eighth embodiment, the number and arrangement of coils and magnets in the seventh embodiment are changed. Although illustration of the measurement object 5 and the spring 6 is omitted, it is assumed that the displacement direction Ddz of the support body 36 including the soft magnetic body 35 is connected in the z direction.

  The displacement detector 15 includes a sensor 26 that detects a change in magnetic flux density in the detection direction Dsz, a soft magnetic body 35 that is displaced in the displacement direction Ddz, a flat magnet 42a that is magnetized in the magnetization direction Dm, and two And a ring-shaped magnet 42b. Note that the vertical direction in FIG. 14 is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction.

  The column portion 36a of the support 36 is provided so as to penetrate the center of the ring-shaped magnet 42b, and has the coil 7 on the outer peripheral portion thereof.

  The sensor 26 is connected to a control circuit (not shown), and the control circuit monitors the output voltage of the sensor 26. Further, the coil 7 is connected to a control circuit, and the control circuit controls the current flowing through the coil 7 based on the output voltage of the sensor 26.

(Operation of displacement detector)
Next, the operation of the eighth embodiment will be described with reference to FIGS.

  In the normal state, the sensor 26 and the soft magnetic body 35 are closest to each other in the thickness center in the z direction. In this state, the magnetic flux density in the detection direction Dsz out of the magnetic flux density B penetrating the detection surface of the sensor 26 is Bz = 0.

  Next, as the amount of displacement increases in the z direction, the magnetic flux density Bz in the negative direction of the detection direction Dsz among the magnetic flux density B penetrating the detection surface of the sensor 26 increases. When the displacement is negative, the magnetic flux density Bz increases as the displacement increases. The relationship between the displacement of the soft magnetic body 35 and the magnetic flux density detected by the sensor 26 is obtained by inverting the positive / negative of the graph of FIG.

  As described above, the sensor 26 detects the magnetic flux density according to the displacement of the soft magnetic body 35, and outputs a signal according to the detected magnetic flux density. The control circuit monitors the output voltage of the sensor 26, calculates the displacement of the soft magnetic body 35 based on the output voltage, and passes a current value corresponding to the calculated displacement to the coil 7. For example, the control circuit may cause a current to flow through the coil 7 so that the displacement of the soft magnetic body 35 is zero, or may be a constant multiple of the displacement of the soft magnetic body 35.

(Effect of 8th Embodiment)
According to the eighth embodiment described above, the same effects as those of the seventh embodiment can be obtained.

[Ninth Embodiment]
FIG. 16A is a front view showing a configuration example of a displacement detection apparatus according to the ninth embodiment. FIG. 16B is a perspective view illustrating a configuration example of the displacement detection device according to the ninth exemplary embodiment.

  In the ninth embodiment, the displacement detection device 10 of the second embodiment is applied, and the measurement target is a blade-type measurement target 52.

  The displacement detection device 16 includes a pair of a sensor 27 that detects a change in magnetic flux density in the detection direction Dsz, a soft magnetic body 37 that is displaced in the displacement direction Ddz, and a flat magnet 43 that is magnetized in the magnetization direction Dm. Have Note that the vertical direction in FIG. 16A is the z-axis direction, the horizontal direction is the x-axis direction, and the depth direction is the y-axis direction, and FIG. 16B shows these axes converted.

  The measurement object 52 has a blade shape and receives airflow F to obtain z-direction buoyancy. In addition, the measurement object 52 is connected to the soft magnetic body 37 via the connection member 53. The measurement object 52 is elastically instructed in the y direction by a spring or the like (not shown).

(Operation of displacement detector)
Next, the operation of the ninth embodiment will be described with reference to FIG.

  When the measurement object 52 receives the air flow F, the measurement object 52 obtains buoyancy in the y direction, and the soft magnetic body 37 is displaced in the displacement direction Ddy by the buoyancy. The magnetic flux density changed by the displacement of the soft magnetic body 37 is detected by the sensor 27. The detection method is the same as in the second embodiment.

(Effect of 9th Embodiment)
According to the ninth embodiment described above, in addition to the effects of the first embodiment, the displacement of the measuring object 52 and the flow rate of the airflow F can be measured from the detected magnetic flux density.

[Tenth embodiment]
FIG. 18A is a perspective view showing a configuration example of a displacement detection device according to the tenth embodiment. FIG. 18B is a front view showing a configuration example of the displacement detection apparatus according to the tenth embodiment. FIG. 18C is a partial cross-sectional view illustrating a configuration example of the displacement detection device according to the tenth embodiment.

  The tenth embodiment is different from the first embodiment in that the shape of the soft magnetic material is a columnar shape having a recess and the shape of the magnet is a ring shape. The measurement object 5 (not shown) is connected so that the displacement direction of the soft magnetic body 38 is Ddy, that is, the y direction.

  The displacement detection device 17 includes a sensor 28 that detects a change in magnetic flux density in the detection direction Dsy, a cylindrical soft magnetic body 38 that has a recess 380 and is connected to the measurement symmetry 5 and is displaced in the displacement direction Ddy, And a ring-shaped magnet 44 magnetized in the magnetic direction Dm. The indented portion 380 is formed over the entire circumference of the soft magnetic body 38, so that even if the soft magnetic body 38 rotates about the axis, the magnetic flux f described later is not changed. . The outer edge of the ring-shaped magnet 44 is provided with a soft magnetic material for increasing the magnetic flux density and enhancing the aging resistance.

  The vertical direction in FIGS. 18A to 18C is the z-axis direction, the horizontal direction in FIGS. 18A and 18B is the x-axis direction, the depth direction in FIG. 18A and the horizontal direction in FIG.

  The soft magnetic body 38 and the magnet 44 are formed symmetrically with respect to the xy plane, and the sensor 28 is arranged on the xy plane with the centers thereof aligned.

(Operation of displacement detector)
Next, the operation of the tenth embodiment will be described with reference to FIG.

  In the normal state, the center of the sensor 28 and the soft magnetic body 38 in the xy plane is closest to each other. The magnetic flux f is formed so as to be directed perpendicularly from the inner wall of the magnet 44 to the surface of the indented portion 380 of the soft magnetic body 38. Therefore, the magnetic flux density in the detection direction Dsy out of the magnetic flux density B penetrating the detection surface of the sensor 28 in this state. By = 0.

  Next, as the amount of displacement increases in the y direction, the magnetic flux density By in the detection direction Dsy of the magnetic flux density B that penetrates the detection surface of the sensor 28 increases in the negative direction. When the soft magnetic body 38 is displaced in the negative y direction, the magnetic flux density By increases in the positive direction as the amount of displacement increases. The relationship between the displacement of these soft magnetic bodies 38 and the magnetic flux density detected by the sensor 28 is expressed in the same manner as in FIG.

(Effect of 10th Embodiment)
According to the tenth embodiment described above, the same effects as those of the first embodiment can be obtained.

[Other embodiments]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The combinations of the sensors, soft magnetic bodies, and magnets of the first to ninth embodiments described above are exemplifications, and these are appropriately selected within a range that does not impair the position of the present invention and does not change the gist of the present invention. You may select and change to a new combination. The soft magnetic material may have the following shape.

  17A to 17C are perspective views showing modifications of the shape of the soft magnetic material.

  As shown in FIG. 17A, the soft magnetic body 38a has a cylindrical shape having an axis in the depth direction, and the displacement direction Ddx is a direction perpendicular to the axis of the cylinder. When the soft magnetic body 38a is used, a sensor that detects the magnetic flux density in the x direction and / or the z direction can be used.

  As shown in FIG. 17B, the soft magnetic body 38b has a cylindrical shape having an axis in the vertical direction, and the displacement directions Ddx and Ddy are directions perpendicular to the axis of the cylinder. When the soft magnetic body 38b is used, a sensor that detects the magnetic flux density in the x direction and / or the y direction can be used.

  As shown in FIG. 17C, the soft magnetic body 38c has a hemispherical shape whose cross section is perpendicular to the xy plane, and the displacement directions Ddx and Ddy are directions perpendicular to the normal line of the cross section. When the soft magnetic body 38c is used, a sensor that detects the magnetic flux density in the x direction, the y direction, and / or the z direction can be used.

  Displacement detection apparatus that suppresses the influence of temperature-dependent characteristics of a magnetic detection element and improves sensitivity to a measurement object is provided.

DESCRIPTION OF SYMBOLS 1 Displacement detection apparatus 2 Sensor 3 Soft magnetic body 4 Magnet 5 Measurement object 6 Spring 7 Coil 10-16 Displacement detection apparatus 20-27 Sensor 30-33 Soft magnetic body 34 Support body 34a Column 35 Soft magnetic body 36 Support body 36a Column Part 37 Soft magnetic body 38a-38c Soft magnetic body 40, 41a, 41b, 42a, 42b, 43 Magnet 50 Rubber membrane 51 Connection member 52 Measuring object 53 Connection member

Claims (3)

A soft magnetic material that is connected to a measurement object and is displaced;
A magnet that forms a magnetic field in a space that is a movable range of the soft magnetic material;
The magnet is disposed in the space that forms a magnetic field, and has a sensor that detects a change in the magnetic field based on the displacement of the soft magnetic body,
The soft magnetic body is a displacement detection device that is displaced within a range including a displacement position where the magnetic flux density detected by the sensor in one detection direction is zero.   The displacement detection device according to claim 1, wherein the sensor detects a change in the magnetic field in each of a plurality of detection directions, and obtains one output from the plurality of detection results.   The displacement detection device according to claim 1, wherein the soft magnetic body is displaced within a range in which a transmitted magnetic flux does not change.

Images