Motion detection device

Abstract

A motion detection device (5) includes a first support body (51), a second support body (52) that moves relative to the first support body, a power generation sensor (100) disposed on the first support body, and a magnetic field generation source (400) supported by the second support body. The power generation sensor includes a magnetic wire (110), a coil (120), and magnetic flux conduction sheets (130, 131). The magnetic flux conduction sheet includes an axially orthogonal portion and an axially parallel portion, and has a wire arrangement portion that fixes the axially orthogonal portion and both end portions of the magnetic wire. The power generation sensor is configured so that a detection region (140) is formed on the side opposite the magnetic lead wire with respect to the axially parallel portion. The magnetic field generation source has a plurality of magnetic poles. The magnetic poles with different polarities sequentially enter the detection area along a track (30) parallel to the axial direction of the magnetic wire and are opposite to the power generation sensor. The magnetic flux direction of each magnetic pole is perpendicular to the moving direction thereof and is a direction intersecting the magnetic wires.

Description

TECHNICAL FIELD

[0001] The present application relates to a motion detection device including a power generation sensor using a magnetic wire exhibiting a large Barkhausen effect. BACKGROUND

[0002] A magnetic wire having a large Barkhausen effect (large Barkhausen jump) is called a Wegener wire or a pulse wire. The magnetic wire includes a core and a skin portion provided in a manner of surrounding the core. One of the core and the skin portion is a soft magnetic (soft magnetic) layer in which a magnetization direction is reversed even under a weak magnetic field, and the other of the core and the skin portion is a hard magnetic (hard magnetic) layer in which the magnetization direction is not reversed unless a strong magnetic field is applied. By winding a coil around such a magnetic wire, a power generation sensor can be constituted.

[0003] When the hard magnetic layer and the soft magnetic layer are magnetized in the same direction in the axial direction of the wire, if the intensity of an external magnetic field in the direction opposite to the magnetization direction thereof is increased and reaches a certain magnetic field intensity, the magnetization direction of the soft magnetic layer is reversed. The reversal of the magnetization direction propagates from a certain portion of the magnetic wire as a starting position to the entire wire, and the magnetization direction of the soft magnetic layer is reversed all at once. At this time, a large Barkhausen effect is exhibited, and a pulse signal is induced in the coil wound around the magnetic wire. When the above-mentioned external magnetic field intensity is further increased and reaches a certain magnetic field intensity, the magnetization direction of the hard magnetic layer is reversed.

[0004] In the present specification, the magnetic field intensity at the time of the reversal of the magnetization direction of the soft magnetic layer is called an "action magnetic field", and the magnetic field intensity at the time of the reversal of the magnetization direction of the hard magnetic layer is called a "stabilization magnetic field".

[0005] The output voltage obtained from the coil is constant regardless of the speed of change of the input magnetic field (external magnetic field), and has a hysteresis characteristic with respect to the input magnetic field, and thus has characteristics such as no jitter. Therefore, the pulse signal generated from the coil is used for a position detection device or the like. Since the output from the coil has electric power, a power generation type sensor (power generation sensor) which does not need to be supplied with external electric power can be constituted.

[0006] In order to exhibit a large Barkhausen effect, it is necessary to reverse only the magnetization direction of the soft magnetic layer from a state in which the magnetization directions of the hard magnetic layer and the soft magnetic layer are consistent. In a state in which the magnetization directions of the hard magnetic layer and the soft magnetic layer are not consistent, even if only the magnetization direction of the soft magnetic layer is reversed, a pulse signal is not generated or is very small, even if a pulse signal is generated.

[0007] Furthermore, in order to maximize the obtained power, it is important that the reversal of the magnetization of the soft magnetic layer spreads throughout the entire magnetic wire from a state in which the magnetization directions of the entire magnetic wire are consistent. When the magnetization directions of the magnetic wire are partially inconsistent, only a very small pulse signal can be obtained. Therefore, it is preferable that the same magnetic field be applied to the entire magnetic wire.

[0008] A motion detection device using a power generation sensor is disclosed in Patent Documents 1, 2, and 3, for example.

[0009] Patent Document 1 discloses a structure for detecting rotation around a rotation axis. The structure includes a 2-pole magnet magnetized in the direction of the rotation axis, and a power generation sensor disposed at a position offset in the radial direction from the rotation axis. The power generation sensor is disposed so that the axial direction of the magnetic wire is parallel to the tangential direction around the circumference of the rotation axis. By rotation of the magnetic pole, the magnetic field in the axial direction of the magnetic wire changes, and after a stable magnetic field in one direction is applied to become a pulse generation preparation state, when an action magnetic field in the opposite direction is applied, a large Barkhausen effect occurs, and a pulse voltage is generated. In Patent Document 1, it is proposed that the variation in magnetic flux density with respect to the rotation angle be increased by changing the magnetization strength of the magnet, thereby suppressing the deviation of the pulse voltage generation position. For the magnetization state of Fig. 2 of Patent Document 1, the variation in magnetic flux density in the vicinity of the magnetic wire is indicated by line Ml in Fig. 3 of the document. In this case, the deviation of the pulse voltage generation position can be suppressed by the steep variation in magnetic flux, but a flat portion in which there is no variation occurs in the vicinity of the magnetic flux density of 0. Therefore, the phase difference of the pulse voltage generation position due to the direction of rotation becomes large. Fig. 4 of Patent Document 1 shows a structure in which the region in which the magnetization strength is changed is improved. In this case, the variation in magnetic flux density is as indicated by line M3 in Fig. 5 of the document, and a flat portion does not occur in the vicinity of the magnetic flux density of 0.

[0010] However, in a configuration in which the power generation sensor is offset with respect to the 2-pole magnet, there is an angle interval in which both ends of the power generation sensor are opposite magnetic poles of the same polarity, and this angle interval widens as the power generation sensor is disposed farther from the center of rotation. Therefore, the characteristic of making the variation in magnetic flux density as in line M3 of Fig. 5 of Patent Document 1 not produce a flat portion is limited to the case in which the power generation sensor is disposed near the center of rotation. Therefore, for example, it cannot be applied to rotation detection of a large-diameter hollow shaft. Furthermore, the variation in magnetic flux density with respect to the rotation angle is not necessarily steep enough, and the pulse voltage generation position can be deviated.

[0011] In the structure of Fig. 2 of Patent Document 2, an annular magnet magnetized in 4 regions in total by dividing each of the regions in the circumferential direction into two halves into the inner circumferential side and the outer circumferential side, and a power generation sensor disposed toward the radial direction. In this case, when the direction of the boundary of the magnetization regions in the circumferential direction coincides with the axial direction of the magnetic wire of the power generation sensor, the magnetic flux density in the vicinity of the magnetic wire is 0, and the magnetic flux density changes greatly in the vicinity thereof. Therefore, the deviation of the pulse voltage generation position is small, and the phase difference of the pulse voltage generation position due to forward rotation / reverse rotation is also small.

[0012] However, since a special magnetized ring magnet having a width close to the length of the power generation sensor is required, the magnet cost is high. Further, there is a technical problem that the weight or inertia of the magnet becomes large. In addition, in manufacturing detection devices of different sizes, a dedicated magnet is required for each size of the detection device.

[0013] A structure in which a bar magnet is used instead of a ring magnet and improved to obtain similar characteristics is shown in FIG. 30(A) of Patent Document 2. However, since the long axis direction of the power generation sensor is arranged in the radial direction, a large width is required in the radial direction, and accordingly the detection device becomes large. Further, in a rotary detection device to be configured as a hollow shaft, there is a technical problem that the ratio of the hollow diameter to the outer diameter cannot be increased.

[0014] FIG. 6 of Patent Document 3 discloses a structure in which a plurality of independent magnets magnetized in the radial direction are arranged in the circumferential direction instead of using a ring magnet, and the long axis direction of the power generation sensor is arranged in the radial direction. The plurality of independent magnets are arranged in the circumferential direction with the magnetic pole direction alternately different. When using independent magnets, unlike a ring magnet, a dedicated magnet is not required in manufacturing detection devices of different sizes, and a general 2-pole magnet can be used, so the magnet cost is low.

[0015] However, in the angle region between adjacent magnets, since the power generation sensor is not opposed to the magnetic pole, there is an angle interval in which the magnetic flux density is flat around 0. Therefore, the phase difference due to the rotation direction becomes large. The change in the magnetic flux density with respect to the angle is also gentle, so the generation position of the pulse voltage also deviates.

[0016] Prior Art Documents Patent Documents Patent Document 1: Japanese Patent No. 6647478 Patent Document 2: International Publication No. 2016 / 010141 Patent Document 3: U.S. Patent No. 8283914 Specification SUMMARY

[0017] Technical Problem to be Solved by the Invention An embodiment of the present application provides a motion detection device that solves at least one of the technical problems generated in the above-described prior art.

[0018] Technical Solution to the Technical Problem An embodiment of the present application provides a motion detection device including: a first support; a second support that relatively moves with respect to the first support; a power generation sensor that is disposed on the first support; and a magnetic field generation source that is supported on the second support. The power generation sensor includes: a magnetic wire that exhibits a large Barkhausen effect; a coil that is wound around the magnetic wire; and a magnetic flux conducting sheet that is composed of a pair of soft magnetic bodies that are mutually symmetrical with respect to a symmetrical plane that is set at an axial center position of the magnetic wire. The pair of magnetic flux conducting sheets includes: a pair of axial orthogonal portions that extend mutually in parallel in an axial orthogonal direction that is orthogonal to the axial direction from both end portions of the magnetic wire; and a pair of axial parallel portions that extend in a direction in which they mutually approach along the axial direction from leading end portions of the pair of axial orthogonal portions, and the approaching ends are opposite each other across a gap in the axial direction. The pair of magnetic flux conducting sheets have a wire arrangement portion that fixes the axial orthogonal portions to the both end portions of the magnetic wire, and is composed of a hole or a groove that penetrates in the axial direction. The power generation sensor is configured so that the side opposite the magnetic wire with respect to the axial parallel portions is set as a detection region. The magnetic field generation source has a plurality of magnetic poles that sequentially enter the detection region along a track that is parallel to the axial direction of the magnetic wire when the second support relatively moves with respect to the first support. The plurality of magnetic poles are disposed on the second support so that magnetic poles of different polarities alternately oppose the power generation sensor across a gap. The magnetic flux direction of each magnetic pole is perpendicular to the moving direction of the magnetic pole (the moving direction of the magnetic pole when the second support relatively moves with respect to the first support), and when opposing the power generation sensor, is a direction that crosses the magnetic wire (the gap direction). The arrangement interval of the plurality of magnetic poles on the track is longer than the entire length of the magnetic wire. The length of the magnetic pole on the track is shorter than the entire length of the magnetic wire, and is 50% or less of the arrangement interval.

[0019] With this structure, when a magnetic pole passes through the detection region of the power generation sensor, the magnetic flux density of the magnetic wire sharply changes from a stable magnetic field in one direction to a stable magnetic field in another direction, and during this change, a flat portion in which the change in the magnetic flux density stagnates does not occur. Therefore, a motion detection device in which the deviation of the pulse generation position is small, and the difference in the pulse generation position caused by the direction of motion is small, can be provided.

[0020] Further, the magnetic field generating source can be configured using a plurality of individual magnets magnetized in the gap direction, and the magnetic field generating source has a plurality of magnetic poles that generate magnetic flux in a direction (gap direction) that is perpendicular to the moving direction of the magnetic poles and that crosses the magnetic wire when the power generation sensor is opposite the magnetic wire. Such individual magnets can be, for example, general 2-pole magnets that can be magnetized by an air core coil, and thus the cost of the magnets can be reduced. Further, since the magnetization direction is the gap direction, the fixing work of the individual magnets to the second support body is easy, and the assembly cost can be reduced.

[0021] Preferably, the length of the magnetic pole on the track is less than half the full length of the magnetic wire. Thereby, the change in the magnetic flux density when the magnetic pole passes through the detection region can be made more drastic.

[0022] Further, preferably, the arrangement interval of the magnetic poles on the track is 1.5 times or more the full length of the magnetic wire. Thereby, when a certain magnetic pole passes through the detection region, the influence of the magnetic field from other magnetic poles can be suppressed, and thus the change in the magnetic flux density can be made more drastic.

[0023] Preferably, the motion detection device further includes a sensor that discriminates the polarity of the magnetic pole located at the central portion in the axial direction of the power generation sensor. With this structure, in addition to the detection position, the motion direction can also be detected. BRIEF DESCRIPTION OF DRAWINGS

[0024] [ Figures 1A-1B ] Figure 1A is a plan view of a rotation detection device of a first comparative example, Figure 1B is a front view thereof.

[0025] [ Figure 1C ] Figure 1C is a waveform chart showing the change in the magnetic flux density with respect to the rotation angle in the rotation detection device of the first comparative example.

[0026] [ Figures 2A-2B ] Figure 2A is a plan view of a rotation detection device of a second comparative example, Figure 2B is a front view thereof.

[0027] [ Figure 2C ] Figure 2C is a waveform chart showing the change in the magnetic flux density with respect to the rotation angle in the rotation detection device of the second comparative example.

[0028] [ Figures 3A-3B ] Figure 3A is a plan view of a rotation detection device of a third comparative example, Figure 3B is a front view thereof.

[0029] [ Figure 3C ]Figure 3C is a waveform chart showing a change in magnetic flux density with respect to a rotation angle in the rotation detection device of the 3rd comparative example.

[0030] [ Figures 4A-4B ] Figure 4A is a plan view of the rotation detection device of the 4th comparative example, Figure 4B is a front view thereof.

[0031] [ Figure 4C ] Figure 4C is a waveform chart showing a change in magnetic flux density with respect to a rotation angle in the rotation detection device of the 4th comparative example.

[0032] [ Figures 5A-5B ] Figure 5A is a plan view of the rotation detection device according to an embodiment of the present application, Figure 5B is a front view thereof.

[0033] [ Figure 5C ] Figure 5C is a waveform chart showing a change in magnetic flux density with respect to a rotation angle in the rotation detection device according to the above embodiment.

[0034] [ Figure 6A ] Figure 6A is a perspective view for explaining a structure example of a power generation sensor used in an embodiment of the present application.

[0035] [ Figure 6B ] Figure 6B is a front view of the power generation sensor.

[0036] [ Figure 7A ] Figure 7A is a perspective view for explaining a structure example of a rotation detection device according to another embodiment of the present application.

[0037] [ Figure 7B ] Figure 7B is a plan view of the rotation detection device of Figure 7A .

[0038] [ Figure 7C ] Figure 7C is a front view of the rotation detection device of Figure 7A .

[0039] [ Figure 8 ] Figure 8 is a plan view for explaining a structure of a rotation detection device according to another embodiment of the present application. DETAILED DESCRIPTION

[0040] Hereinafter, in order to understand the principle of the embodiments of the present application, several comparative examples are shown, and then the embodiments of the present application are explained.

[0041] Figure 1A and Figure 1B This refers to the rotation detection device 1 of the first comparative example. Figure 1C This represents the change in magnetic flux density relative to the rotation angle.

[0042] The rotation detection device 1 includes: a bipolar magnet 12 rotating about a rotation axis 11, and a power generation sensor 13 with a magnetic wire 14 arranged orthogonally to the rotation axis 11. The power generation sensor 13 includes the magnetic wire 14, a coil 15 wound around the magnetic wire 14, and a pair of cylindrical ferrite cores 16 respectively attached to both ends of the magnetic wire 14. The axis 17 of the magnetic wire 14 is orthogonal to the rotation axis 11, and the center position 18 of the magnetic wire 14 (the center position of the axis 17) is located on the rotation axis 11. The bipolar magnet 12 is plate-shaped, radially magnetized, with one half being the N pole and the other half being the S pole.

[0043] If the axis 17 of the magnetic wire 14 is aligned with the magnetic pole boundary line 12a Figure 1A If the angle is set to 0 degrees and the angle value is increased in the counterclockwise direction CCW, then the change in magnetic flux density accompanying the rotation of the 2-pole magnet 12 around the rotation axis 11 becomes... Figure 1C The magnetic flux density shown is a sinusoidal waveform. Here, magnetic flux density refers to the magnetic flux density through the magnetic conductor 14, that is, the density of the magnetic flux component in the direction parallel to the axis 17 of the magnetic conductor 14 near the conductor 14. The same applies in the descriptions of other comparative examples and embodiments described later. Figure 1C The operating magnetic field and stabilizing magnetic field of the magnetic conductor 14 are also shown.

[0044] When the dipolar magnet 12 rotates counterclockwise (CCW), if the magnetic flux density is lower than the negative stabilizing magnetic field, it enters a positive pulse preparation state (positive setting state). Subsequently, if the magnetic flux density exceeds the positive operating magnetic field, a positive pulse PP is generated. Conversely, when the dipolar magnet 12 rotates counterclockwise (CCW), if the magnetic flux density exceeds the positive stabilizing magnetic field, it enters a negative pulse preparation state (negative setting state). Subsequently, if the magnetic flux density is lower than the negative operating magnetic field, a negative pulse NP is generated. Therefore, as... Figure 1C As shown, a positive pulse PP is generated near 0 degrees, and a negative pulse NP is generated near 180 degrees.

[0045] Similarly, when the dipolar magnet 12 rotates clockwise (CW), if the magnetic flux density is lower than the negative stabilizing magnetic field, it enters a positive pulse preparation state (positive setting state); subsequently, if the magnetic flux density exceeds the positive operating magnetic field, a positive pulse PP is generated. Conversely, when the dipolar magnet rotates clockwise (CW), if the magnetic flux density exceeds the positive stabilizing magnetic field, it enters a negative pulse preparation state (negative setting state); subsequently, if the magnetic flux density is lower than the negative operating magnetic field, a negative pulse NP is generated. Therefore, as...Figure 1C As shown, a negative pulse NP is generated near 0 degrees, and a positive pulse PP is generated near 180 degrees.

[0046] Since the change in the magnetic flux density with respect to the angle has a limited slope, the pulse generation position (the angle at which the pulse is generated) is not consistent between the counterclockwise rotation CCW and the clockwise rotation CW, and an offset of the pulse generation position, i.e., a phase difference PS, is generated. More specifically, the phase difference PS is generated near 0 degrees and near 180 degrees.

[0047] In this comparative example, as shown in Figure 1C Since the change in the magnetic flux density with respect to the rotation angle is gentle, the deviation of the pulse generation position is large, and the phase difference PS caused by the rotation direction is also large.

[0048] The structure of this comparative example cannot be applied to a configuration in which mechanical components are combined at both ends of the rotation shaft, and cannot constitute a detection device in a hollow shaft shape, since the power generation sensor 13 is disposed on the rotation axis 11.

[0049] Figure 2A and Figure 2B shows a rotation detection device 2 of the second comparative example, Figure 2C shows the change in the magnetic flux density with respect to the rotation angle.

[0050] The rotation detection device 2 includes a 2-pole magnetized ring magnet 22 that rotates around the rotation axis 11, and a power generation sensor 13. The structure of the power generation sensor 13 is the same as that of the first comparative example. The axial center position 18 of the magnetic wire 14 is offset in the radial direction from the rotation axis 11, and the axial direction 17 of the magnetic wire 14 is perpendicular to the rotation axis 11 and is in the tangential direction of a point on the circumference around the rotation axis 11. The 2-pole magnetized ring magnet 22 is a circular ring shape centered on the rotation axis 11, and is magnetized in a direction parallel to the rotation axis 11, and on the surface thereof opposite the power generation sensor 13 across a gap, one-half of the angular region is an N pole, and the remaining one-half of the angular region is an S pole.

[0051] If the angle at which the axial direction 17 of the magnetic wire 14 is parallel to the magnetic pole boundary line 22a is set to 0 degrees, and the angle value is increased in the counterclockwise direction CCW, then the change in the magnetic flux density accompanying the rotation of the 2-pole magnetized ring magnet 22 around the rotation axis 11 becomes a trapezoidal waveform as shown in Figure 2A Figure 2C

[0052] The operation of the power generation sensor 13 caused by the change in the magnetic flux density is the same as that of the first comparative example.

[0053] ​​In the angular regions where the two ends of the power generation sensor 13 are opposite magnetic poles of the same polarity, the magnetic flux density is 0, resulting in flat regions with a magnetic flux density of 0 centered at 0 degrees and 180 degrees respectively. Correspondingly, a large phase difference PS is generated near 0 degrees and near 180 degrees due to the direction of rotation. The greater the offset from the rotation axis 11 to the power generation sensor 13, the larger this phase difference PS is.

[0054] The comparative example requires a ring magnet 22 that is magnetized throughout its circumference, and its manufacture necessitates the preparation of a dedicated magnetizing yoke. Furthermore, a ring magnet 22 that matches the size (diameter) of the detection device is required. Therefore, a universal magnet cannot be used, and there are also technical issues related to the high cost of the magnet.

[0055] The structure of Patent Document 1 can be classified as the category of Comparative Example 2.

[0056] Figure 3A and Figure 3B This refers to the rotation detection device 3 of the third comparative example. Figure 3C This represents the change in magnetic flux density relative to the rotation angle.

[0057] The rotation detection device 3 includes an annular magnet 23 rotating around a rotation axis 11 and a power generation sensor 13. The structure of the power generation sensor 13 is the same as that in the first comparative example. The axial center position 18 of the magnetic wire 14 is offset radially from the rotation axis 11, and the axial direction 17 of the magnetic wire 14 is radial. The annular magnet 23 is circular in shape centered on the rotation axis 11, and is multipole magnetized in a direction parallel to the rotation axis 11. It has four magnetized regions 24 on the surface opposite the power generation sensor 13 with a gap between them.

[0058] Specifically, the surface of the annular magnet 23 opposite to the power generation sensor 13 is radially divided into an inner diameter portion and an outer diameter portion, and circumferentially divided into two portions around the rotation axis 11, thus dividing it into four magnetization regions 24. More specifically, half of the angled region of the inner diameter portion is an arc-shaped N pole region, and the remaining half is an arc-shaped S pole region. Similarly, half of the angled region of the outer diameter portion is an arc-shaped S pole region, and the remaining half is an arc-shaped N pole region. The outer side of the S pole region of the inner diameter portion is adjacent to the N pole region of the outer diameter portion, and the outer side of the N pole region of the inner diameter portion is adjacent to the S pole region of the outer diameter portion. The boundaries of the magnetization regions 24 of the inner and outer diameter portions are aligned in the circumferential direction, and the magnetic pole boundary line 25 is radially aligned.

[0059] If the axis 17 of the magnetic conductor 14 is parallel to the magnetic pole boundary line 25... Figure 3A If the angle is set to 0 degrees and the angle value is increased in the counterclockwise direction CCW, then the change in magnetic flux density accompanying the rotation of the ring magnet 23 around the rotation axis 11 becomes... Figure 3Ca trapezoidal waveform as shown.

[0060] The operation of the power generation sensor 13 caused by the change in magnetic flux density is the same as in the first comparative example.

[0061] Near 0 degrees and 180 degrees where the magnetic flux density becomes 0, the change in magnetic flux density is steep, so the deviation of the pulse generation position is small, and the phase difference PS caused by the direction of rotation is also small.

[0062] On the other hand, since the long axis direction of the power generation sensor 13 is the radial direction, there is a technical problem in that the outer diameter of the detection device becomes large.

[0063] In addition, even in the structure of this comparative example, a ring-shaped magnet 23 that is magnetized over the entire circumference is needed, and a special magnetizing yoke needs to be prepared for the manufacture. Furthermore, a ring-shaped magnet 23 that matches the size (diameter) of the detection device is needed. Therefore, a magnet that has versatility cannot be used, and there is a technical problem in that the cost of the magnet is high.

[0064] The structure of Patent Document 2 can be classified into the category of the third comparative example.

[0065] Figure 4A and Figure 4B a rotation detection device 4 that represents the fourth comparative example, Figure 4C indicates the change in magnetic flux density with respect to the rotation angle.

[0066] This rotation detection device 4 includes a ring-shaped support substrate 26 that rotates around the rotation axis 11, two independent magnets 27 that are arranged on the support substrate 26 with a space in the circumferential direction, and a power generation sensor 13. The structure of the power generation sensor 13 is the same as in the first comparative example.

[0067] The axial center position 18 of the magnetic wire 14 is offset in the radial direction from the rotation axis 11, and the axial direction 17 of the magnetic wire 14 is in the radial direction. The two independent magnets 27 are magnetized in the radial direction and are arranged at an angle of 180 degrees around the rotation axis 11. One of the two independent magnets 27 has an N pole arranged on the inner side near the rotation axis 11 and is fixed to the support substrate 26, and the other of the two independent magnets 27 has an S pole arranged on the inner side near the rotation axis 11 and is fixed to the support substrate 26. The pole boundary line 27a of each independent magnet 27 is in the tangential direction around the circumference of the rotation axis 11 (more accurately, the tangential direction at the position of each independent magnet 27). Each independent magnet 27 is arranged on the support substrate 26 so that, when viewed from the power generation sensor 13, one pole is opposed to one end portion of the magnetic wire 14 and the other pole is opposed to the other end portion of the magnetic wire 14.

[0068] If the magnetic wire 13 is located midway between the two independent magnets 27 Figure 4AThe angle at the time is set to 0 degrees, and the angle value is set to increase in the counterclockwise direction (CCW), the variation in the magnetic flux density accompanying the rotation of the independent magnet 27 around the rotation axis 11 becomes Figure 4C The waveform shown in the drawing.

[0069] The operation of the power generation sensor 13 caused by the variation in the magnetic flux density is the same as in the first comparative example.

[0070] In this comparative example, since the variation in the magnetic flux density with respect to the angle is small, it is easy to cause a deviation in the pulse voltage generation position. Further, the vicinity of 0 degrees and 180 degrees at which the magnetic flux density becomes 0 belongs to the angle interval between adjacent independent magnets 27, and is a flat portion in which the magnetic flux density does not vary. Therefore, the phase difference PS caused by the rotation direction is large.

[0071] Further, as in the third comparative example, since the long axis direction of the power generation sensor 13 is the radial direction, there is a technical problem in which the outer shape of the detection device becomes large.

[0072] On the other hand, in this comparative example, a general 2-pole magnet that can be magnetized by a hollow coil can be used as the independent magnet 27, and thus the magnet cost is low. In addition, there is an advantage in that the same structure of the magnet 27 can be used for detection devices of different sizes.

[0073] However, the independent magnet 27 needs to be fixed in the direction alignment on the support substrate 26 so that the pole boundary line 27a that cannot actually be recognized is in the circumferential tangent direction, and thus the assembly work is complicated, and accordingly there is a technical problem in which the assembly cost increases.

[0074] The structure of Patent Document 3 can be classified into the category of the fourth comparative example.

[0075] Figure 5A and Figure 5B A rotation detection device 5 that represents one example of a motion detection device according to an embodiment of the present application, Figure 5C The variation in the magnetic flux density with respect to the rotation angle is shown in the drawing.

[0076] The rotation detection device 5 includes a first support body 51, a second support body 52 that relatively moves with respect to the first support body 51, a power generation sensor 100 that is supported on the first support body 51, and a magnetic field generation source 400 that is supported on the second support body 52.

[0077] The first support body 51 is a support substrate in this embodiment, and the power generation sensor 100 is supported on one main surface thereof. The second support body 52 is a ring-shaped support substrate that rotates around a rotation axis 40 in this embodiment. The magnetic field generation source 400 includes a plurality of (two in this embodiment) independent magnets M1, M2 that are arranged on the second support body 52 with a gap in the circumferential direction.

[0078] The power generation sensor 100 includes a magnetic conductor wire 110, a coil 120 wound around the magnetic conductor wire 110, and a pair of L-shaped flux conducting sheets 130, 131 joined to both end portions of the magnetic conductor wire 110, respectively, and is configured to take the lower side of the second support body 52 (the side opposite to the first support body 51) as a detection region 140. Figure 5B The specific configuration example of the power generation sensor 100 will be described later with reference to Figure 6A and Figure 6B .

[0079] The axial center position 113, which is the axial center position of the magnetic conductor wire 110, is offset from the rotation axis 40 in the radial direction, and the axial x of the magnetic conductor wire 110 is along the circumferential direction around the rotation axis 40 (more specifically, the tangential direction at the axial center position 113 on the circumference around the rotation axis 40 passing through the axial center position 113 of the magnetic conductor wire 110).

[0080] The two independent magnets M1, M2 are magnetized in the direction parallel to the rotation axis 40 and are arranged at equal intervals, i.e., at an angle of 180 degrees, on the circumference around the rotation axis 40. One of the two independent magnets M1, M2 is arranged so that the N pole n1 is opposite to the power generation sensor 100 when approaching the power generation sensor 100 and is fixed to the second support body 52, and the other is arranged so that the S pole s1 is opposite to the power generation sensor 100 when approaching the power generation sensor 100 and is fixed to the second support body 52. When the second support body 52 rotates around the rotation axis 40, each magnet n1, s1 moves along the circular orbit 30.

[0081] Thus, the magnetic field generation source 400 has a plurality of magnets n1, s1 arranged on the second support body 52, and the plurality of magnets n1, s1 sequentially enter the detection region 140 along the orbit 30 substantially parallel to the axial x of the magnetic conductor wire 110 when the second support body 52 relatively rotates (an example of relative movement) with respect to the first support body 51. At this time, the magnets n1, s1 of different polarities are alternately opposite to the power generation sensor 100 with the gap 31 therebetween. Since the independent magnets M1, M2 are magnetized in the direction parallel to the rotation axis 40, the magnetic flux direction of each magnet n1, s1 is perpendicular to the moving direction of the magnet n1, s1, and is the direction crossing the magnetic conductor wire 110 when opposite to the power generation sensor 100, i.e., the opening direction (gap direction) of the gap 31 between the magnet n1, s1 and the power generation sensor 100.

[0082] The arrangement interval λ of the plurality of magnets n1, s1 on the orbit 30, i.e., the interval between the circumferentially adjacent magnets n1, s1, is longer than the full length Lw of the magnetic conductor wire 110 (refer to Figure 6BMore specifically, in this example, the pole arrangement interval λ is 1.5 times or more of the full length Lw of the magnetic wire 110. Further, the length α (length along the track 30) of the magnetic poles n1, s1 on the track 30 is shorter than the full length Lw of the magnetic wire 110, and is 50% or less of the pole arrangement interval λ. In this example, the length α of the magnetic poles n1, s1 on the track 30 is half or less of the full length Lw of the magnetic wire 110.

[0083] When the second support body 52 rotates together with the two independent magnets M1, M2 in the counterclockwise direction CCW, the magnetic flux density becomes a positive pulse preparation state (positive setting state) if it is lower than the negative stabilized magnetic field, and thereafter a positive pulse PP is generated if it exceeds the positive operation magnetic field. In addition, when the second support body 52 rotates together with the two independent magnets M1, M2 in the counterclockwise direction CCW, the magnetic flux density becomes a negative pulse preparation state (negative setting state) if it exceeds the positive stabilized magnetic field, and thereafter a negative pulse NP is generated if it is lower than the negative operation magnetic field. Therefore, as shown in FIG. 6, a negative pulse NP is generated near 90 degrees, and a positive pulse PP is generated near 270 degrees. Figure 5C

[0084] Similarly, when the second support body 52 rotates together with the two independent magnets M1, M2 in the clockwise direction CW, the magnetic flux density becomes a positive pulse preparation state (positive setting state) if it is lower than the negative stabilized magnetic field, and thereafter a positive pulse PP is generated if it exceeds the positive operation magnetic field. In addition, when the second support body 52 rotates together with the two independent magnets M1, M2 in the clockwise direction CW, the magnetic flux density becomes a negative pulse preparation state (negative setting state) if it exceeds the positive stabilized magnetic field, and thereafter a negative pulse NP is generated if it is lower than the negative operation magnetic field. Therefore, as shown in FIG. 7, a positive pulse PP is generated near 90 degrees, and a negative pulse NP is generated near 270 degrees. Figure 5C

[0085] The change in the magnetic flux density with respect to the rotation angle is very sharp near 90 degrees and 270 degrees. Therefore, the deviation of the pulse generation position is small, and the phase difference PS, which is the shift of the pulse generation position corresponding to the rotation direction, is extremely small. Further, since the angle difference from the operation magnetization to the stabilized magnetic field is very small, the range (reversal range) in which the so-called pulse loss occurs when the moving direction (rotation direction) is reversed is narrow.

[0086] ​​In addition, since the long axis direction of the power generation sensor 100 is the tangential direction of the circumference, the outer shape of the rotation detection device 5 can be made small. From another viewpoint, the diameter of the hollow portion of the second support body 52 can be increased. Furthermore, a general independent magnet Ml, M2 that can be magnetized in the thickness direction by a hollow coil can be used, so the cost of the magnet can be reduced. Of course, the same design of the independent magnet Ml, M2 can be used commonly for rotation detection devices of different sizes, so a special magnet of a dedicated design is not required. Moreover, only the N pole or the S pole of the independent magnet Ml, M2 that is magnetized in the thickness direction needs to be fixed to the second support body 52 alternately in one direction, so the assembly work is simple compared to the fourth comparative example in which the pole boundary needs to be aligned with the radial direction, and accordingly the assembly cost can be reduced.

[0087] As described above, the configuration interval λ of the plurality of magnets n1, s1 on the track 30 is longer than the full length of the magnetic wire 110 (preferably 1.5 times or more), so as shown in FIG. 6, a flat portion in which the magnetic flux density is 0 appears in the intermediate region between 90 degrees and 270 degrees of the pulse generation. Thus, the influence of the magnetic field from the adjacent magnets n1, s1 on the track 30 can be separated, and the magnetic flux density near 90 degrees and 270 degrees can be changed sharply. This tendency is further enhanced by setting the length α of the magnets n1, s1 on the track 30 to be 50% or less of the pole configuration interval λ. Figure 5C

[0088] Furthermore, as described above, the length α of the magnets n1, s1 on the track 30 is shorter than the full length of the magnetic wire 110. Thus, near 90 degrees and 270 degrees, a sharp change in the magnetic flux density can be ensured without generating a flat portion in the change in the magnetic flux density. By setting the length α of the magnets n1, s1 to be half or less of the full length of the magnetic wire 110, the change in the magnetic flux density can be made more sharp, so this is preferable.

[0089] Figure 6A is a perspective view for illustrating a structure example of the power generation sensor 100, Figure 6B is a front view as viewed from the arrow 101 direction of Figure 6A . The power generation sensor 100 moves relative to the pole 401 of the magnetic field generation source 400 (for example, an independent magnet), and thus the power generation sensor 100 generates a pulse signal. The relative movement of the power generation sensor 100 to the magnetic field generation source 400 is achieved by movement of at least one of the power generation sensor 100 and the magnetic field generation source 400. Hereinafter, an example in which the relative movement is achieved by movement of the magnetic field generation source 400 will be mainly described.

[0090] ​The power generation sensor 100 includes a magnetic wire 110 exhibiting a large Barkhausen effect, a coil 120 wound on the magnetic wire 110, and a pair of magnetic flux conducting sheets 130, 131 having soft magnetic body members. The coil 120 is wound on the magnetic wire 110 so that the first end portion 111 and the second end portion 112 of the magnetic wire 110 are exposed by the same length. In the present embodiment, the coil 120 is wound on the magnetic wire 110 between the pair of magnetic flux conducting sheets 130, 131. The pair of magnetic flux conducting sheets 130, 131 are respectively magnetically coupled to the first end portion 111 and the second end portion 112 of the magnetic wire 110.

[0091] The pair of magnetic flux conducting sheets 130, 131 have structures having substantially the same shape and the same size. More specifically, the pair of magnetic flux conducting sheets 130, 131 are configured to be mutually symmetrical with respect to a symmetry plane 115 (an imaginary plane for explaining a geometric configuration) orthogonal to the axial direction x at a central position (hereinafter referred to as "axial center position") 113 of the magnetic wire 110 in the axial direction x (lengthwise direction, wire length direction). The pair of magnetic flux conducting sheets 130, 131 include axial orthogonal portions 133 extending in parallel to each other from both end portions 111, 112 of the magnetic wire 110 in an axial orthogonal direction z orthogonal to the axial direction x, and axial parallel portions 134 extending from leading end portions of the axial orthogonal portions 133 in a direction approaching to each other in the axial direction x.

[0092] Both end portions 111, 112 of the magnetic wire 110 are respectively fixed to base end portions of the axial orthogonal portions 133 of the pair of magnetic flux conducting sheets 130, 131. More specifically, wire arrangement portions 130a, 131a formed of holes or grooves extending through in the axial direction x are provided at the base end portions of the axial orthogonal portions 133. Figure 6A FIG. 1 shows an example in which the wire arrangement portions 130a, 131a are formed of holes. In the case where the wire arrangement portions 130a, 131a are formed of grooves, the grooves are preferably grooves extending in the axial orthogonal direction z to open to an end surface on the side opposite to the detection region 140 described later. The first end portion 111 and the second end portion 112 of the magnetic wire 110 are fixed to the axial orthogonal portions 133 of the pair of magnetic flux conducting sheets 130, 131 in a state where the magnetic wire 110 penetrates the axial orthogonal portions 133 at the wire arrangement portions 130a, 131a. More specifically, the end portions 111, 112 of the magnetic wire 110 are fixed to the axial orthogonal portions 133 and coupled to each other by arranging a resin (omitted from illustration) in the holes or grooves constituting the wire arrangement portions 130a, 131a. Thus, the magnetic wire 110 and the pair of magnetic flux conducting sheets 130, 131 are mechanically coupled to each other and magnetically coupled to each other.

[0093] The proximal ends 134a of the axial parallel portions 134 of the pair of magnetic flux conducting sheets 130, 131 are opposed to each other across the symmetry plane 115 of the axial center position 113 of the magnetic wire 110. That is, the proximal ends 134a of the axial parallel portions 134 are opposed to each other with a gap in the axial direction x. The middle of the gap in the axial direction x corresponds to the position of the axial center position 113 in the axial direction x, and thus the distance from the proximal ends 134a of the pair of axial parallel portions 134 to the symmetry plane 115 in the axial direction x is equal. The distance L of the gap in the axial direction x is set to 5% to 50% of the distance D between the pair of axial orthogonal portions 133 at the coupling position of the magnetic wire 110 and the axial orthogonal portions 133, and more preferably to 20% to 40%. More specifically, the distance D is the distance in the axial direction x between the inner sides 130b, 131b (inner sides of the axial orthogonal portions 133) of the pair of magnetic flux conducting sheets 130, 131 opposite each other in the axial direction x at the coupling position of the magnetic wire 110.

[0094] The soft magnetic member constituting the magnetic flux conducting sheets 130, 131 is made of a material having a coercive force lower than that of the magnetic wire 110 and a relative permeability of 500 or more. Such a material has characteristics of low magnetic resistance, low hysteresis, low self-induction, and the like. Thus, even if a high-frequency alternating magnetic field generated when the magnetic field generating source 400 moves at high speed is applied, the output characteristics of the power generation sensor 100 are less affected. Specifically, the soft magnetic member is preferably made of a material of Ni-based ferrite or Mn-based ferrite.

[0095] The power generation sensor 100 is configured to set a region on the side opposite the magnetic wire 110 with respect to the axial parallel portions 134 as a detection region 140. The magnetic field generating source 400 generating a magnetic field to be detected is disposed in the detection region 140. The power generation sensor 100 and the magnetic field generating source 400 are disposed with a gap 31 (clearance) having the axial orthogonal direction z. The gap 31 can be a complete air gap, and for example, a printed board 45 constituting the first support body 51 can be mounted. That is, the power generation sensor 100 can be disposed on one main surface side of the printed board 45, and the magnetic field generating source 400 can be disposed on the other main surface side thereof. An electric component and / or an electronic component can be mounted on one or both of the main surfaces of the printed board 45. In one specific example, the power generation sensor 100 is mounted on one main surface of the printed board 45.

[0096] Typically, the magnetic field generating source 400 moves relative to the power generation sensor 100 to pass through the detection region 140. That is, the detection region 140 is disposed on a movement path of the magnetic field generating source 400. In this embodiment, the magnetic field generating source 400 is composed of a plurality of independent magnets magnetized in the axial orthogonal direction z. Thus, the magnetic field generating source 400 has a plurality of magnetic poles 401 opposite to the power generation sensor 100 (more specifically, the axial parallel portion 134) when moving along the track 30 passing through the detection region 140.

[0097] The plurality of magnetic poles 401 are disposed so that magnetic poles 401 of different polarity are alternately opposite to the power generation sensor 100 when the second support body 52 moves relative to the first support body 51 (the printed board 45) in this embodiment. The power generation sensor 100 outputs a pulse voltage according to a change in magnetic field generated when the magnetic poles 401 move through the detection region 140. By signal processing and counting the pulse voltage, a position detection device, i.e., an encoder (an example of a movement detection device) that generates position information can be configured.

[0098] The moving direction, i.e., the movement direction, of the magnetic poles 401 in the detection region 140 is along the axial direction x. That is, substantially parallel to the magnetic wire 110. In other words, the track 30 has a portion substantially parallel to the axial direction x in the detection region 140. In one specific example, the track 30 has a straight portion parallel to the axial direction x in the detection region 140. The track 30 as a whole can be linear, or can have a curved portion. In another specific example, the track 30 has a circular arc portion having a tangent parallel to the axial direction x in the detection region 140. The circular arc portion can be located with a rotation axis 40 parallel to the axial orthogonal direction z as a center. The track 30 as a whole can be a circular arc portion, i.e., a circular shape. In addition, the track 30 can also have a straight portion, an elliptical portion, or the like, a portion having a non-circular arc shape. Figure 5A and Figure 5B In the example shown, the track 30 is a circular shape.

[0099] The pair of magnetic flux conducting sheets 130, 131 is configured to correct a magnetic field formed in a space containing the magnetic flux conducting sheets 130, 131 by the magnetic field generating source 400 disposed in the detection region 140 to a magnetic field in the axial direction x, and to apply to the magnetic wire 110.

[0100] If more specifically described, the magnetic flux conducting sheet 130, 131 composed of a soft magnetic member has an axially orthogonal portion 133 of a substantially rectangular parallelepiped shape and an axially parallel portion 134 of a substantially rectangular parallelepiped shape, which connects an end portion, i.e., a front end portion, provided on a side opposite to the magnetic field generation source 400, i.e., a side of the detection region 140, of the axially orthogonal portion 133, and has an L-letter shape bent at a right angle at a connecting portion of the axially orthogonal portion 133 and the axially parallel portion 134. The axially parallel portion 134 extends along the axial direction x to cover the magnetic wire 110, i.e., to shield between the magnetic wire 110 and the detection region 140. The axially parallel portions 134 of the pair of magnetic flux conducting sheets 130, 131 having mutually symmetrical shapes extend to the axially central side of the magnetic wire 110, and their proximal ends 134a are opposed to each other at intervals near the axially central position 113 of the magnetic wire 110. The proximal ends 134a form planes orthogonal to the axial direction x, and the two planes forming the two proximal ends 134a are parallel to each other and opposed to each other in the axial direction x. The distance L in the direction x between the two proximal ends 134a is the distance between the two planes forming the two proximal ends 134a.

[0101] The magnetic flux conducting sheets 130, 131 composed of a soft magnetic member and the coil 120 are fixed to a case (omitted from the drawing) covering them by an adhesive resin, fitting, or other appropriate fixing method. As described above, the both end portions 111, 112 of the magnetic wire 110 are fixed to the wire arrangement portions 130a, 131a composed of two through holes or grooves by a resin (omitted from the drawing). Thus, the power generation sensor 100 is composed of a structure in which the pair of magnetic flux conducting sheets 130, 131, the coil 120, and the magnetic wire 110 are fixed to and integrated with each other.

[0102] The both ends of the coil 120 can be connected to external electrodes provided at the axially parallel portions 134. By soldering the external electrodes to wiring conductors provided on one main face of the printed board 45, the power generation sensor 100 can be surface-mounted on the printed board 45.

[0103] In the power generation sensor 100 configured as above, the magnetic field of the detection region 140 is conducted to both end portions 111, 112 of the magnetic wire 110 through the magnetic flux conducting sheets 130, 131 having the soft magnetic member. Also, since the axial parallel portion 134 parallel to the axial direction x of the magnetic wire 110 exists between the detection region 140 and the magnetic wire 110, the magnetic flux from the detection region 140 toward the axial middle portion (a position in the middle of the axial direction) of the magnetic wire 110 is shielded by the axial parallel portion 134. In particular, when the distance L in the axial direction x of the approaching end 134a of the axial parallel portion 134 of the pair of magnetic flux conducting sheets 130, 131 from each other is set to 5% to 50% of the distance D between the axial orthogonal portion 133 at the coupling position of the magnetic wire 110, an excellent magnetic shielding effect can be obtained. Therefore, since the magnetic field in the axial direction x can be applied over a wide range in the axial direction x of the magnetic wire 110, a large Barkhausen effect can be sufficiently induced, and a high output signal can be obtained.

[0104] Further, since the power generation sensor 100 includes the magnetic flux conducting sheets 130, 131, and the magnetic flux conducting sheets 130, 131 are fixed and coupled to each other with the magnetic wire 110, the magnetic field generation source 400 (typically a magnet) as a detection medium can be disposed in the detection region 140. Therefore, it is easy to combine with the magnetic field generation source 400 having different shapes and / or polarities.

[0105] When the power generation sensor 100 moves relative to the magnetic field generation source 400, the magnetic pole 401 of the magnetic field generation source 400 moves along the track 30 passing through the detection region 140. The track 30 includes a straight portion parallel to the axial direction x in the detection region 140, or includes a circular arc portion having a tangent parallel to the axial direction x in the detection region 140. Therefore, when the magnetic pole 401 passes through the detection region 140, the magnetic pole 401 opposes the axial parallel portion 134, and thus the magnetic flux generated by the magnetic pole 401 is applied to the magnetic wire 110 through the magnetic flux conducting sheets 130, 131.

[0106] Since the axial parallel portion 134 of the magnetic flux conducting sheets 130, 131 extends in the axial direction x of the magnetic wire 110, the magnetic flux is difficult to enter the axial middle portion of the magnetic wire 110 from the magnetic pole 401 by the magnetic shielding effect thereof. The axial parallel portion 134 extending in the axial direction x of the magnetic wire 110 can concentrate a large amount of magnetic flux. Therefore, even if the magnetic flux generated from the magnetic pole 401 is weak, the magnetic field required for a large Barkhausen effect can be applied to the magnetic wire 110. Further, the axial parallel portion 134 can oppose the magnetic pole 401 over a wide range within the detection region 140, and the magnetic flux is suppressed from entering the axial middle portion of the magnetic wire 110.

[0107] Therefore, the magnetic pole 401 is opposed to the axial center position 113 of the magnetic wire 110, and the magnetic flux conducted from the pair of magnetic flux conducting pieces 130, 131 to both end portions 111, 112 of the magnetic wire 110 is in a balanced state. From this state, if the magnetic pole 401 is slightly moved in either direction along the track 30, the magnetic flux density in the magnetic wire 110 is drastically changed. Thus, the change in the position of the magnetic flux density with respect to the magnetic pole 401 becomes steep.

[0108] Figure 7A is a perspective view for illustrating a specific configuration example of the rotation detection device 5A, Figure 7B is a plan view thereof. Furthermore, Figure 7C is a front view illustrating the structure in the vicinity of the power generation sensor 100 as viewed from the right side of Figure 7B is a front view illustrating the structure in the vicinity of the power generation sensor 100 as viewed from the right side of

[0109] The rotation detection device 5A is an example of an encoder, and detects a rotational position about a rotational axis 40 coinciding with a central axis of the rotational shaft 50. The rotation detection device 5A includes the power generation sensor 100 and a magnetic field generation source 400. The rotation detection device 5A also includes, in this example, a sensor 55 (e.g., a magnetic sensor). Although not illustrated, the rotation detection device 5A can further include a count processing circuit that performs signal processing and counting of a pulse output generated by the power generation sensor 100, and a nonvolatile memory or the like that stores a count result of the count processing circuit. The count processing circuit can be configured to perform a counting operation in consideration of an output of the sensor 55.

[0110] The power generation sensor 100 is disposed on the first support body 51, and is supported by the first support body 51. In the present embodiment, the first support body 51 also mounts the sensor 55.

[0111] The magnetic field generation source 400 is fixed to the second support body 52. The second support body 52 is relatively moved with respect to the first support body 51. Specifically, the second support body 52 is coupled (fixed) to the rotational shaft 50, and rotates about the rotational axis 40 together with the rotational shaft 50. Therefore, the second support body 52 can be a part of a rotating body. In contrast, the first support body 51 is fixedly disposed, and is maintained in a non-rotating state. Thus, the magnetic field generation source 400 rotates about the rotational axis 40 together with the second support body 52, and is relatively moved with respect to the first support body 51.

[0112] Typically, the rotational shaft 50 is rotated by a driving force from a driving shaft of a motor (not illustrated). In a case where the motor is bidirectionally driven, the rotational shaft 50 is rotated in both the counterclockwise direction CCW and the clockwise direction CW in correspondence therewith. The first support body 51 can be a printed board 45 disposed along a plane orthogonal to the rotational axis 40.

[0113] The magnetic field generating source 400 includes a plurality of, i.e., 2k (k = 2 in the illustrated example) independent magnets Ml, M2,..., which are fixed to the second support body 52 in this example. The independent magnets Ml, M2,..., which are magnetized in a direction parallel to the rotation axis 40, i.e., an axial orthogonal direction z, are arranged at equal angular intervals around the rotation axis 40. The independent magnets Ml, M2,..., which are plate-shaped (more specifically, circular plate-shaped) magnetized in a thickness direction in this example, are not limited to this shape. It is also possible to use a magnet whose shape in plan view is an arc (specifically, a sector with a radially inner portion cut away). Figure 6A The illustrated cuboid or rectangular plate shape, it is also possible to use a magnet whose shape in plan view is an arc (specifically, a sector with a radially inner portion cut away).

[0114] In plan view from a direction parallel to the rotation axis 40 (see FIG. 6), the N poles n1, n2,... and the S poles s1, s2,... are arranged alternately in the circumferential direction. That is, the second support body 52 is rotated in one direction around the rotation axis 40, so that magnetic poles of different polarity, i.e., N poles and S poles, are alternately brought into the detection region 140 (see FIG. 6) of the power generation sensor 100, generating an alternating magnetic field in the vicinity of the power generation sensor 100. Figure 7B Figure 7C

[0115] The power generation sensor 100 is mounted to one main surface of the first support body 51 (the printed board 45). The magnetic wire 110 of the power generation sensor 100 is located on a tangent line of a circle whose center is on the rotation axis 40, and the axial center position 113 of the magnetic wire 110 is located on a point of tangency of the tangent line. The power generation sensor 100 is arranged so that the magnetic force conducted from the two magnetic flux conducting pieces 130, 131 is balanced when the center of any one or a plurality of the magnetic poles n1, n2,..., nk; s1, s2,..., sk of the independent magnets Ml, M2,... is aligned with the axial center position 113 of the magnetic wire 110.

[0116] The axial parallel portion 134 of the magnetic flux conducting piece 130, 131 is formed with a detection region opposing surface 134b opposing the detection region 140 on the detection region 140 side. The detection region opposing surface 134b is a flat surface parallel to the axial direction x. This detection region opposing surface 134b is formed with a magnetic flux conducting end that guides the magnetic flux from the magnetic pole to the inside of the magnetic flux conducting piece 130, 131 when the magnetic pole is arranged in the detection region 140.

[0117] ​​The axial parallel portion 134 of the magnetic flux conducting sheet 130, 131 is welded to a wiring pattern (not shown) formed on one main surface of the first support body 51 (printed wiring board 45), whereby the power generation sensor 100 is mounted on the first support body 51 (printed wiring board 45). The power generation sensor 100 is configured so that the axial direction x of the magnetic wire 110 is along a tangent line at a point (tangent point) on a circumference centered on the rotation axis 40, and so that the axial center position 113 of the magnetic wire 110 coincides with the tangent point. The detection region 140 of the power generation sensor 100 is located on the side opposite the magnetic wire 110 with respect to the axial parallel portion 134, and in this example, is a region on the other main surface side of the first support body 51 (printed wiring board 45).

[0118] In this example, the second support body 52 is configured as a circular ring shape that surrounds the rotation axis 40. More specifically, the second support body 52 is configured as a plate-shaped body in a circular ring shape, is disposed along a plane orthogonal to the rotation axis 40, and is parallel to the first support body 51 (printed wiring board 45). In the second support body 52, a plurality of individual magnets M1, M2,... are fixed on a surface opposite the other main surface of the first support body 51 (printed wiring board 45). In this embodiment, the plurality of individual magnets M1, M2,... are disposed at equal intervals along the circumferential direction around the rotation axis 40. In the specific example shown, four individual magnets M1, M2, M3, M4 are disposed at 90-degree angular intervals around the rotation axis 40, and they are fixed to the second support body 52 in a manner opposite the first support body 51 (printed wiring board 45). The distance from the rotation axis 40 to the center of the individual magnets M1, M2,... can be equal to the distance from the rotation axis 40 to the axial center position 113 of the magnetic wire 110. That is, in a plan view along the rotation axis 40, the magnetic wire 110 and the individual magnets M1, M2,... are located on circumferences of equal radius centered on the rotation axis 40, whereby a positional relationship is established in which they can be opposite in a direction parallel to the rotation axis 40. The second support body 52 is preferably a magnetic yoke configured of a soft magnetic material.

[0119] The second support body 52 rotates around the rotation axis 40 together with the rotation shaft 50, whereby the individual magnets M1, M2,... move on the circular circumferential track 30 passing through the detection region 140 with the rotation axis 40 as a center. The axial direction x of the magnetic wire 110 is parallel to a tangent line at a point (tangent point) on the circumferential track 30, and the axial center position 113 is located on a perpendicular line (in this example, a perpendicular line parallel to the rotation axis 40) that is perpendicular to the tangent line at the tangent point. In other words, the axial center position 113 of the magnetic wire 110 is located at a point (tangent point) on a circumference centered on the rotation axis 40 and having a radius equal to the circumferential track 30, and the magnetic wire 110 is along a tangent line at the tangent point.

[0120] The distance between the first support 51 and the second support 52 in the direction of the rotation axis 40 is set to be able to pass through the rotation of the second support 52, so that the independent magnets Ml, M2,... can enter the detection region 140 of the power generation sensor 100.

[0121] In the printed board 45 constituting the first support 51, on the main surface on which the power generation sensor 100 is mounted, a sensor 55 constituted of a magnetic sensor, for example, is also mounted. On the main surface of the printed board 45, other electrical components or electronic components such as the above-mentioned count processing circuit, nonvolatile memory, and the like can also be mounted.

[0122] The sensor 55 is configured to be able to detect the polarity of the magnetic pole opposite the central portion of the power generation sensor 100. The sensor 55 is constituted of a magnetic sensor such as a Hall IC, for example, and outputs an H signal when an N pole is detected (i.e., when the N pole is opposite the central portion of the power generation sensor 100), and outputs an L signal when an S pole is detected (i.e., when the S pole is opposite the central portion of the power generation sensor 100). Thereby, the sensor 55 discriminates the polarity of the magnetic pole passing in its vicinity, and as a result, outputs a discrimination signal that identifies the polarity of the magnetic pole opposite the central portion of the power generation sensor 100. In the present embodiment, the sensor 55 is configured to detect the magnetic pole at a position that is 180 degrees in phase difference around the rotation axis 40, i.e., a position that is symmetrical about the rotation axis 40, with respect to the power generation sensor 100. When k is even (e.g., 2), the sensor 55 detects a magnetic pole of the same polarity as the magnetic pole opposite the central portion of the power generation sensor 100. When k is odd (e.g., 3), the sensor 55 detects a magnetic pole of the opposite polarity to the magnetic pole opposite the central portion of the power generation sensor 100. In either case, the sensor 55 is able to detect the polarity of the magnetic pole opposite the central portion of the power generation sensor 100.

[0123] With such a configuration, by rotation in the counterclockwise direction CCW around the rotation axis 40, each time one magnetic pole pair nl, sl; n2, s2;...; nk, sk passes through the detection region 140 along the circumferential orbit 30, one negative pulse NP and one positive pulse PP are generated in that order (refer to Figure 5C ). In addition, by rotation in the clockwise direction CW around the rotation axis 40, each time one magnetic pole pair nl, sl; n2, s2;...; nk, sk passes through the detection region 140 along the circumferential orbit 30, one positive pulse PP and one negative pulse NP are generated in that order (refer to Figure 5C ). Then, from these pulses, and from the sensor 55 that outputs a discrimination signal indicating the polarity of the magnetic pole located on the circumferential orbit 30 between the magnetic flux conducting sheets 130, 131, the rotation position and the rotation direction can be identified.

[0124] Specifically, in a case where the sensor 55 detects the N-pole when the negative pulse NP is generated, and in a case where the sensor 55 detects the S-pole when the positive pulse PP is generated, it is possible to recognize that the rotation direction is the counterclockwise direction CCW. On the other hand, in a case where the sensor 55 detects the S-pole when the positive pulse PP is generated, and in a case where the sensor 55 detects the N-pole when the negative pulse NP is generated, it is possible to recognize that the rotation direction is the clockwise direction CW.

[0125] With Figure 6A and Figure 6B the configuration interval λ of the plurality of magnetic poles on the track 30 is longer than the full length of the magnetic wire 110. In this example, the configuration interval λ is 1.5 times or more of the full length Lw of the magnetic wire 110. Further, the length α of the magnetic pole on the track 30 (length along the track 30) is shorter than the full length Lw of the magnetic wire 110, and is 50% or less of the magnetic pole configuration interval λ. In this example, the length α of the magnetic pole on the track 30 is half or less of the full length Lw of the magnetic wire 110.

[0126] With such a structure, the same effects as those of the structure illustrated in Figure 6A and Figure 6B are achieved.

[0127] Figure 8 is a plan view for explaining the structure of a rotation detection device 6, which is an example of a movement detection device according to another embodiment of the present application.

[0128] The rotation detection device 6 includes a first support body 51A, a second support body 52A that relatively moves with respect to the first support body 51A, a power generation sensor 100 supported to the first support body 51A, and a magnetic field generation source 400 supported to the second support body 52A. The first support body 51A is a support substrate in this embodiment, and supports the power generation sensor 100 on one main surface thereof. The second support body 52A is a cylindrical shape that rotates around the rotation axis 40 in this embodiment. The magnetic field generation source 400 includes a plurality of (two in this embodiment) independent magnets M1, M2 that are arranged on the outer peripheral surface of the second support body 52A at intervals in the circumferential direction.

[0129] The power generation sensor 100 has the same structure as that of Figure 6A or the like, and is configured to include the magnetic wire 110, the coil 120 wound around the magnetic wire 110, and a pair of L-shaped flux conducting pieces 130, 131 that are respectively coupled to both end portions of the magnetic wire 110, with the second support body 52A side (rotation axis 40 side) as a detection region 140. That is, the rotation detection device 6 is a radial gap type in which the direction in which the gap between the magnetic field generation source 400 (independent magnet) and the power generation sensor 100 is open (gap direction) is the radial direction.

[0130] The axial center position 113 of the magnetic conductor 110 is radially offset from the rotation axis 40, and the axial x of the magnetic conductor 110 is along the circumferential direction around the rotation axis 40 (more specifically, it is the tangential direction at the axial center position 113 on the circumference around the rotation axis 40 passing through the axial center position 113 of the magnetic conductor 110). The two independent magnets Ml, M2 are magnetized in the radial direction (gap direction) orthogonal to the rotation axis 40, and are arranged at equal intervals, i.e., at an angle interval of 180 degrees, on the circumference around the rotation axis 40. One of the two independent magnets Ml, M2 is arranged such that the N pole n1 opposes the power generation sensor 100 when approaching the power generation sensor 100, and is fixed to the outer peripheral surface of the second support body 52A. The other of the two independent magnets Ml, M2 is arranged such that the S pole s1 opposes the power generation sensor 100 when approaching the power generation sensor 100, and is fixed to the outer peripheral surface of the second support body 52A.

[0131] When the second support body 52A rotates around the rotation axis 40, each of the magnetic poles n1, s1 moves along the circular track 30. In this way, the magnetic field generation source 400 has a plurality of magnetic poles n1, s1 arranged on the second support body 52A, and the plurality of magnetic poles n1, s1 sequentially enter the detection region 140 along the track substantially parallel to the axial x of the magnetic conductor 110 when the second support body 52A relatively rotates (an example of relative movement) with respect to the first support substrate. At this time, the magnetic poles n1, s1 of different polarities alternately oppose the power generation sensor 100 with the gap therebetween. Since the two independent magnets Ml, M2 are magnetized in the radial direction orthogonal to the rotation axis 40, the magnetic flux direction of each of the magnetic poles n1, s1 is perpendicular to the moving direction of the magnetic pole n1, s1, and is a direction intersecting the magnetic conductor 110 when opposing the power generation sensor 100, i.e., a direction in which the gap between the magnetic pole n1, s1 and the power generation sensor 100 is open (gap direction).

[0132] The arrangement interval λ of the plurality of magnetic poles n1, s1 on the track 30 is longer than the full length of the magnetic conductor 110. More specifically, in this example, the arrangement interval λ is 1.5 times or more of the full length Lw of the magnetic conductor 110. In addition, the length α of the magnetic poles n1, s1 on the track 30 (length along the track 30) is shorter than the full length Lw of the magnetic conductor 110, and is 50% or less of the magnetic pole arrangement interval λ. In this example, the length α of the magnetic poles n1, s1 on the track 30 is half or less of the full length Lw of the magnetic conductor 110.

[0133] According to this structure, the same effects as those of the structure shown in Figs. 1 to 8 can be achieved. Figure 6A and Figure 6B The same effects as those of the structure shown in Figs. 1 to 8 can be achieved.

[0134] The above describes an embodiment of the present application, but the present application can be implemented in other forms as shown in the following examples.

[0135] The foregoing embodiments mainly described a device for detecting rotation, i.e., a device for detecting relative movement along an endless track. However, it can also be configured as a detection device for detecting movement (linear motion, etc.) along an end track, such as an arc or a straight line. In this case, at least one of the first support supporting the power generation sensor 100 and the second support supporting the magnetic field generator moves along the track. The magnetic field generator is supported on the second support, such that by moving in one direction, magnetic poles of different polarities alternately enter the detection area of ​​the power generation sensor 100. On the second support, only the N pole and the S pole need to be alternately arranged along the track; the total number of magnetic poles can be either even or odd.

[0136] Furthermore, the above embodiments illustrate an example of a magnetic field source with multiple poles composed of multiple independent magnets, but a multi-pole magnetized magnet designed according to the desired orbital shape can also be used to construct the magnetic field source. Specifically, in the case of a rotation detection device, a ring-shaped multi-pole magnetized magnet surrounding the rotation axis 40 can also be used to construct the magnetic field source. For example, in Figure 7A In the case of the structure shown, for a toroidal hard magnet, multiple magnetic poles are formed by setting local magnetization regions (4 magnetization regions) spaced apart circumferentially at the same positions as the individual magnets M1 to M4, thereby serving as a magnetic field source. The magnetization direction is parallel to the rotation axis 40, that is, the axial orthogonal direction z. When viewed from one direction of the rotation axis 40, the four-pole magnetized toroidal magnet thus formed has a structure consisting of k (k is a natural number. Preferably k ≥ 2. In the example shown, k = 2) pairs of magnetic poles (pairs of N poles and S poles) arranged alternately on the circumference centered on the rotation axis 40, and has k N poles n1, n2, ..., nk and k S poles s1, s2, ..., sk. The arrangement interval λ of the multiple magnetic poles (magnetization regions) on the track 30 is longer than the total length Lw of the magnetic wire 110, preferably more than 1.5 times the total length Lw of the magnetic wire 110. Furthermore, the length α (length along the track 30) of the magnetic poles (magnetized regions) on the track 30 is shorter than the total length Lw of the magnetic wire 110, and the spacing λ between the magnetic poles is less than 50%. Preferably, the length α of the magnetic poles on the track 30 is less than half the total length Lw of the magnetic wire 110.

[0137] Furthermore, magnetic poles do not necessarily have to be magnets (magnetized hard magnets). For example, a soft magnet (yoke) that guides magnetic flux from a magnet can also be used, with the surface (typically the end face) of the soft magnet serving as the magnetic pole.

[0138] In addition, in the above-described embodiment, the axial orthogonal portion of the magnetic flux conducting sheet has a first portion extending from the magnetic wire 110 toward the detection region 140, and a second portion extending from the magnetic wire 110 toward the side opposite to the detection region 140, but even if the second portion is omitted, there is no substantial influence on the magnetic flux conducting function (magnetic collecting function).

[0139] In addition to the above, various design changes can be made within the scope of the matters recited in the claims.

[0140] Explanation of Reference Numerals 5, 5A, 6 Rotation detection device 30 Track 31 Gap 40 Rotation axis 45 Printed board 50 Rotation shaft 51, 51A First support body 52, 52A Second support body 55 Sensor 100 Power generation sensor 110 Magnetic wire 113 Axial center position 115 Symmetrical plane 120 Coil 130, 131 Magnetic flux conducting sheet 130a, 131a Wire arrangement portion 133 Axial orthogonal portion 134 Axial parallel portion 134a Approach end 140 Detection region 400 Magnetic field generation source 401 Magnetic pole Lw Total length of magnetic wire M1, M2, M3, M4 Independent magnet PP Positive pulse NP Negative pulse PS Phase difference n1, n2 N-pole (magnetic pole) s1, s2 S-pole (magnetic pole) x Axial direction z Axial orthogonal direction λ Arrangement interval of magnetic poles α Length of magnetic pole

Claims

1. A motion detection device, characterized in that, Include: First support structure; The second support body is movable relative to the first support body; A power generation sensor, which is disposed on the first support; and A magnetic field generator is provided, which is supported by the second support body. The power generation sensor includes: a magnetic wire exhibiting the large Backhausen effect; a coil wound around the magnetic wire; and a flux-conducting sheet composed of a pair of soft magnetic bodies symmetrical about a plane of symmetry positioned relative to the axial center of the magnetic wire. The pair of flux-conducting sheets includes: a pair of axially orthogonal portions extending parallel to each other from both ends of the magnetic wire in an axially orthogonal direction; and a pair of axially parallel portions extending from the front ends of the pair of axially orthogonal portions in a direction approaching each other along the axial direction, with their approaching ends spaced apart from each other in the axial direction. The pair of flux-conducting sheets has a wire arrangement portion that fixes the axially orthogonal portions to both ends of the magnetic wire, and is formed by a hole or slot extending along the axial direction. The power generation sensor is configured such that the detection area is located on the side opposite to the magnetic conductor relative to the axially parallel portion. The magnetic field generator has multiple magnetic poles. As the second support moves relative to the first support, these magnetic poles sequentially enter the detection area along a track parallel to the axial direction of the magnetic wire. The multiple magnetic poles are arranged on the second support such that magnetic poles of different polarities alternately face the power generation sensor with gaps between them. The magnetic flux direction of each magnetic pole is perpendicular to the direction of movement of that pole, and when opposite to the power generation sensor, it is the direction that intersects with the magnetic wire. The spacing between the plurality of magnetic poles on the track is longer than the total length of the magnetic conductor. The length of the magnetic pole on the track is shorter than the total length of the magnetic conductor and is less than 50% of the configuration interval.

2. The motion detection device as described in claim 1, characterized in that, The length of the magnetic pole on the track is less than half the total length of the magnetic conductor.

3. The motion detection device as described in claim 2, characterized in that, The spacing between the magnetic poles on the track is more than 1.5 times the total length of the magnetic conductor.

4. The motion detection device according to any one of claims 1 to 3, characterized in that, It also includes a sensor that determines the polarity of the magnetic pole located at the center of the axial direction of the power generation sensor.

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