Motion detection device

Abstract

The motion detection device (5) includes a first support (51), a second support (52) that moves relative to the first support, a power generation sensor (100) disposed on the first support, and a magnetic field generating source (400) supported on the second support. The power generation sensor includes a magnetic wire (110), a coil (120), and a magnetic flux conducting plate (130, 131). The magnetic flux conducting plate includes an axially orthogonal portion and an axially parallel portion, and has a wire arrangement portion that fixes the axially orthogonal portion and both ends of the magnetic wire. The power generation sensor is configured such that the side opposite to the magnetic wire is set as the detection area (140) relative to the axially parallel portion. The magnetic field generating source has multiple magnetic poles. Magnetic poles of different polarities enter the detection area sequentially along a track (30) parallel to the axis of the magnetic wire and are opposite to the power generation sensor. The magnetic flux direction of each magnetic pole is perpendicular to its direction of movement and is the direction that intersects with the magnetic wire.

Description

Technical Field

[0001] This invention relates to a motion detection device, including a power generation sensor utilizing a magnetic wire exhibiting the large Backhausen effect. Background Technology

[0002] Magnetic wires exhibiting the Big Backhausen effect (Big Backhausen jump) are called Wiegand wires or pulse wires. These magnetic wires consist of a core and a skin portion surrounding the core. One of the core and the skin portion is a soft magnetic layer that reverses its magnetization direction even under a weak magnetic field, while the other is a hard magnetic layer whose magnetization direction does not reverse unless a strong magnetic field is applied. By winding a coil around such a magnetic wire, a power generation sensor can be constructed.

[0003] When the hard magnetic layer and the soft magnetic layer are magnetized in the same direction along the axis of the conductor, if the strength of an external magnetic field in the opposite direction to their magnetization direction increases and reaches a certain strength, the magnetization direction of the soft magnetic layer reverses. This reversal of magnetization direction propagates from a portion of the magnetic conductor as a starting point to the entire conductor, and the magnetization direction of the soft magnetic layer reverses simultaneously. At this time, the Big Barkhausen effect is exhibited, inducing a pulse signal in the coil wound on the magnetic conductor. When the strength of the external magnetic field increases further and reaches a certain strength, the magnetization direction of the hard magnetic layer reverses.

[0004] In this specification, the magnetic field strength when the magnetization direction of the soft magnetic layer is reversed is referred to as the "operating magnetic field," and the magnetic field strength when the magnetization direction of the hard magnetic layer is reversed is referred to as the "stable magnetic field."

[0005] The output voltage obtained from the coil is constant regardless of the rate of change of the input magnetic field (external magnetic field), and it exhibits hysteresis characteristics with respect to the input magnetic field, thus possessing features such as no jitter. Therefore, the pulse signal generated from the coil is used in position detection devices, etc. Since the output from the coil has electrical power, it can be used to construct a power-generating sensor (power-generating sensor) that does not require an external power supply.

[0006] To reproduce the large Backhausen effect, it is necessary to start from a state where the magnetization directions of the hard and soft magnetic layers are aligned, and then reverse the magnetization direction of only the soft magnetic layer. When the magnetization directions of the hard and soft magnetic layers are not aligned, even if only the magnetization direction of the soft magnetic layer is reversed, no pulse signal will be generated, or if a pulse signal is generated, it will be extremely small.

[0007] Furthermore, to maximize the obtained power, it is important that the magnetization reversal of the soft magnetic layer is distributed throughout the entire magnetic conductor, starting from a state where the magnetization direction is consistent across the entire magnetic conductor. When the magnetization direction of the magnetic conductor is inconsistent across parts, only very small pulse signals can be obtained. Therefore, it is preferable to apply the same magnetic field across the entire magnetic conductor.

[0008] Motion detection devices using power generation sensors are disclosed, for example, in Patent Documents 1, 2, and 3.

[0009] Patent Document 1 discloses a structure for detecting rotation about a rotation axis. This structure includes a two-pole magnet magnetized along the rotation axis and a power generation sensor disposed radially offset from the rotation axis. The power generation sensor is configured such that the axial direction of the magnetic conductor is parallel to the tangential direction of the circumference around the rotation axis. By rotating the magnetic poles, the magnetic field along the axial direction of the magnetic conductor changes. After applying a stabilizing magnetic field in one direction to prepare for pulse generation, when an operating magnetic field in the opposite direction is applied, a large Backhausen effect is exhibited, generating a pulse voltage. In Patent Document 1, it is proposed to increase the change in magnetic flux density relative to the rotation angle by changing the magnetization intensity of the magnet, thereby suppressing the deviation of the pulse voltage generation position. For the magnetization state in Figure 2 of Patent Document 1, the change in magnetic flux density near the magnetic conductor is represented by line M1 in Figure 3 of the same document. In this case, the deviation of the pulse voltage generation position can be suppressed by a steep change in magnetic flux, but a flat region without change is generated near the point where the magnetic flux density is 0. Therefore, the phase difference of the pulse voltage generation position due to the rotation direction becomes larger. Figure 4 of Patent Document 1 shows an improved structure for changing the region of magnetization intensity. In this case, the change in magnetic flux density is shown by line M3 in Figure 5 of the document, and no flat portion is produced near the magnetic flux density of 0.

[0010] However, in the configuration where the power generation sensor is offset relative to the two-pole magnet, there exists an angular range where the two ends of the power generation sensor are opposite to the same polarity magnetic poles, and this angular range widens as the power generation sensor is positioned further away from the center of rotation. Therefore, the characteristic of preventing the change in magnetic flux density from producing a flat portion, as shown by line M3 in Figure 5 of Patent Document 1, is limited to cases where the power generation sensor is positioned near the center of rotation. Thus, it cannot be applied, for example, to the rotation detection of large-diameter hollow shafts. Furthermore, the change in magnetic flux density relative to the rotation angle may not be steep enough, leading to deviations in the position where the pulse voltage is generated.

[0011] In the structure shown in Figure 2 of Patent Document 2, a ring magnet is magnetized into four regions, each divided into an inner and outer circumferential side. The power generation sensor is configured to face the radial direction. In this case, when the direction of the magnetized region boundary related to the circumference is aligned with the axis of the magnetic conductor of the power generation sensor, the magnetic flux density near the magnetic conductor is 0, and a significant change in magnetic flux density occurs in its vicinity. Therefore, the deviation in the pulse voltage generation position is small, and the phase difference in the pulse voltage generation position caused by forward / reverse rotation is also small.

[0012] However, the cost of the magnet is high because it requires a specially magnetized ring magnet with a width close to the length of the power generation sensor. Furthermore, there are technical issues related to increased magnet weight or inertia. Additionally, when manufacturing detection devices of different sizes, a dedicated magnet is required for each size.

[0013] Figure 30(A) of Patent Document 2 shows a structure that uses a rod-shaped magnet instead of a ring magnet and improves upon it to obtain similar properties. However, since the long axis of the power generation sensor is arranged in the radial direction, a larger width is required in the radial direction, and the detection device becomes larger accordingly. In addition, when constructing a rotational detection device with a hollow shaft, there is a technical problem that the ratio of the hollow diameter to the outer diameter cannot be increased.

[0014] Figure 6 of Patent Document 3 discloses a structure that does not use a ring magnet, but instead arranges multiple independent magnets magnetized radially in the circumferential direction, with the long axis of the power generation sensor arranged in the radial direction. The multiple independent magnets are arranged circumferentially with alternating magnetic pole directions. Unlike ring magnets, using independent magnets eliminates the need for dedicated magnets when manufacturing detection devices of different sizes; general-purpose 2-pole magnets can be used, thus reducing magnet costs.

[0015] However, in the angular region between adjacent magnets, since the power generation sensor is not opposite the magnetic poles, there exists an angular interval where the magnetic flux density is flat near 0. Therefore, the phase difference due to the direction of rotation increases. The change in magnetic flux density relative to the angle is also gradual, thus increasing the positional deviation of the pulse voltage generation.

[0016] Existing technical documents

[0017] Patent documents

[0018] Patent Document 1: Japanese Patent No. 6647478

[0019] Patent Document 2: International Publication No. 2016 / 010141

[0020] Patent Document 3: US Patent No. 8283914 Summary of the Invention

[0021] The technical problem that the invention aims to solve

[0022] One embodiment of the present invention provides a motion detection device that solves at least one technical problem arising in the prior art.

[0023] Technical solutions to solve technical problems

[0024] One embodiment of the present invention provides a motion detection device comprising: a first support; a second support, the second support being movable relative to the first support; a power generation sensor disposed on the first support; and a magnetic field generating source supported on the second support. The power generation sensor comprises: 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 mutually symmetrical about a plane of symmetry set at the axial center position 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 and facing each other axially. The pair of flux-conducting sheets have wire arrangement portions that fix the axially orthogonal portions to both ends of the magnetic wire, and are formed by holes or slots extending along the axial direction. The power generation sensor is configured such that the side opposite to the magnetic conductor is designated as the detection area relative to the axially parallel portion. The magnetic field generator has multiple magnetic poles that, as the second support moves relative to the first support, sequentially enter the detection area along a track parallel to the axial direction of the magnetic conductor. These 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 its direction of movement (the direction of movement of the magnetic pole when the second support moves relative to the first support), and when facing the power generation sensor, it is in the direction intersecting the magnetic conductor (the gap direction). The spacing between the multiple magnetic poles on the track is longer than the total length of the magnetic conductor. The length of the magnetic poles on the track is shorter than the total length of the magnetic conductor and is less than 50% of the spacing.

[0025] With this structure, when the magnetic pole passes through the detection area of ​​the power generation sensor, the magnetic flux density through the magnetic wire changes abruptly from a stabilized magnetic field in one direction to a stabilized magnetic field in another direction. During this change, no flat portion where the change in magnetic flux density stagnates is generated. Therefore, a motion detection device with minimal deviation in pulse generation position and minimal difference in pulse generation position caused by the direction of motion can be provided.

[0026] Furthermore, the magnetic field generator can be constructed using multiple individual magnets magnetized along the gap direction. The magnetic field generator has multiple magnetic poles that generate magnetic flux perpendicular to the direction of movement of the magnetic poles and in the direction of intersection with the magnetic wires (gap direction) when opposite the power generation sensor. Such individual magnets can be, for example, general-purpose 2-pole magnets that can be magnetized by hollow coils, thus reducing magnet costs. Furthermore, since the magnetization direction is the gap direction, fixing the individual magnets to the second support is easy, reducing assembly costs.

[0027] Preferably, the length of the magnetic pole on the track is less than half the total length of the magnetic conductor. This allows for a more abrupt change in magnetic flux density as the magnetic pole passes through the detection area.

[0028] Furthermore, preferably, the spacing between the magnetic poles on the track is at least 1.5 times the total length of the magnetic conductor. This allows the influence of magnetic fields from other poles to be suppressed when a magnetic pole passes through the detection area, thus enabling a more rapid change in magnetic flux density.

[0029] Preferably, the motion detection device further includes a sensor that determines the polarity of the magnetic pole located at the center of the axial direction of the power generation sensor. This structure enables the detection of both position and direction of motion. Attached Figure Description

[0030] [ Figure 1A-1B ] Figure 1A This is a top view of the rotation detection device of the first comparative example. Figure 1B This is its main view.

[0031] [ Figure 1C ] Figure 1C This is a waveform diagram showing the change in magnetic flux density relative to the rotation angle in the rotation detection device of the first comparative example.

[0032] [ Figure 2A-2B ] Figure 2A This is a top view of the rotation detection device of the second comparative example. Figure 2B This is its main view.

[0033] [ Figure 2C ] Figure 2C This is a waveform diagram showing the change in magnetic flux density relative to the rotation angle in the rotation detection device of the second comparative example.

[0034] [ Figures 3A-3B ] Figure 3A This is a top view of the rotation detection device of the third comparative example. Figure 3B This is its main view.

[0035] [ Figure 3C ] Figure 3C This is a waveform diagram showing the change in magnetic flux density relative to the rotation angle in the rotation detection device of the third comparative example.

[0036] [ Figures 4A-4B ] Figure 4A This is a top view of the rotation detection device of the fourth comparative example. Figure 4B This is its main view.

[0037] [ Figure 4C ] Figure 4C This is a waveform diagram showing the change in magnetic flux density relative to the rotation angle in the rotation detection device of the fourth comparative example.

[0038] [ Figures 5A-5B ] Figure 5A This is a top view of a rotation detection device according to an embodiment of the present invention. Figure 5B This is its main view.

[0039] [ Figure 5C ] Figure 5C This is a waveform diagram showing the change in magnetic flux density relative to the rotation angle in the rotation detection device according to the above embodiment.

[0040] [ Figure 6A ] Figure 6A This is a perspective view illustrating an example of the structure of a power generation sensor used in one embodiment of the present invention.

[0041] [ Figure 6B ] Figure 6B This is the front view of the aforementioned power generation sensor.

[0042] [ Figure 7A ] Figure 7A This is a perspective view illustrating a structural example of a rotation detection device according to other embodiments of the present invention.

[0043] [ Figure 7B ] Figure 7B yes Figure 7A A top view of the rotating detection device.

[0044] [ Figure 7C ] Figure 7C yes Figure 7A The front view of the rotation detection device.

[0045] [ Figure 8 ] Figure 8 This is a top view illustrating the structure of a rotation detection device according to other embodiments of the present invention. Detailed Implementation

[0046] Hereinafter, in order to understand the principle of the embodiments of the present invention, several comparative examples are shown, and then the embodiments of the present invention are described.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] Because the change in magnetic flux density relative to angle has a finite slope, the pulse generation position (the angle at which the pulse is generated) is inconsistent when rotating counterclockwise (CCW) compared to clockwise (CW), resulting in a shift in the pulse generation position, i.e., a phase difference PS. More specifically, a phase difference PS will occur near 0 degrees and near 180 degrees.

[0053] In this comparative example, such as Figure 1C As shown, since the change in magnetic flux density relative to the rotation angle is gradual, the deviation of the pulse generation position is large, and the phase difference PS caused by the rotation direction is also large.

[0054] Because the power generation sensor 13 is positioned on the rotation axis 11, the structure of this comparative example is not suitable for configurations where mechanical parts are attached to both ends of the rotation axis, nor can it be used to construct a hollow shaft-shaped detection device.

[0055] Figure 2A and Figure 2B This refers to the rotation detection device 2 of the second comparative example. Figure 2C This represents the change in magnetic flux density relative to the rotation angle.

[0056] The rotation detection device 2 includes a bipolar magnetized annular magnet 22 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 perpendicular to the rotation axis 11 and along the tangent direction at a point on the circumference of the rotation axis 11. The bipolar magnetized annular magnet 22 is annular in shape centered on the rotation axis 11 and magnetized in a direction parallel to the rotation axis 11. On its surface opposite the power generation sensor 13 with a gap, half of the angular region is the N pole and the remaining half of the angular region is the S pole.

[0057] If the axis 17 of the magnetic conductor 14 is parallel to the magnetic pole boundary line 22a... Figure 2A If the angle is set to 0 degrees and the angle value is increased in the counterclockwise direction of CCW, then the change in magnetic flux density accompanying the rotation of the dual-pole magnetized ring magnet 22 around the rotation axis 11 becomes... Figure 2C The trapezoidal waveform shown.

[0058] The operation of the power generation sensor 13 caused by the change in magnetic flux density is the same as that in the first comparative example.

[0059] 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.

[0060] 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.

[0061] The structure of Patent Document 1 can be classified as the category of Comparative Example 2.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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 3CThe trapezoidal waveform shown.

[0066] The operation of the power generation sensor 13 caused by the change in magnetic flux density is the same as that in the first comparative example.

[0067] Near 0 degrees and 180 degrees, where the magnetic flux density becomes zero, the change in magnetic flux density is steep. Therefore, the deviation in the position of pulse generation is small, and the phase difference PS caused by the rotation direction is also small.

[0068] On the other hand, since the long axis of the power generation sensor 13 is radial, there is a technical problem that the outer diameter of the detection device becomes larger.

[0069] Furthermore, even in the structure of this comparative example, a ring magnet 23 magnetized throughout the entire circumference is required, and its manufacture necessitates the preparation of a dedicated magnetizing yoke. Additionally, a ring magnet 23 matching the size (diameter) of the detection device is required. Therefore, a universal magnet cannot be used, and there is also the technical problem of high magnet cost.

[0070] The structure of Patent Document 2 can be classified as the category of the third comparative example.

[0071] Figure 4A and Figure 4B This refers to the rotation detection device 4 in the fourth comparative example. Figure 4C This represents the change in magnetic flux density relative to the rotation angle.

[0072] The rotation detection device 4 includes: an annular support base plate 26 that rotates around a rotation axis 11, two independent magnets 27 arranged circumferentially on the support base plate 26 at intervals, and a power generation sensor 13. The structure of the power generation sensor 13 is the same as that of the first comparative example.

[0073] The axial center position 18 of the magnetic wire 14 is radially offset from the rotation axis 11, and the axial direction 17 of the magnetic wire 14 is radial. Two independent magnets 27 are radially magnetized and arranged at 180-degree intervals around the rotation axis 11. One of the two independent magnets 27 has its N pole positioned inside the rotation axis 11 and is fixed to the support base plate 26, while the other has its S pole positioned inside the rotation axis 11 and is fixed to the support base plate 26. The magnetic pole boundary line 27a of each independent magnet 27 is along the tangential direction of the circumference around the rotation axis 11 (more precisely, the tangential direction of the location of each independent magnet 27). Each independent magnet 27 is arranged on the support base plate 26 such that, when opposite to the power generation sensor 13, one magnetic pole is opposite one end of the magnetic wire 14, and the other magnetic pole is opposite the other end of the magnetic wire 14.

[0074] If the magnetic wire 13 is located between two independent magnets 27 Figure 4AIf 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 independent magnet 27 around the rotation axis 11 becomes... Figure 4C The waveform shown is as shown.

[0075] The operation of the power generation sensor 13 caused by the change in magnetic flux density is the same as that in the first comparative example.

[0076] In this comparative example, because the change in magnetic flux density relative to the angle is small, it is easy to cause a deviation in the position of the pulse voltage generation. Furthermore, the 0-degree and 180-degree ranges where the magnetic flux density becomes zero belong to the angular interval between adjacent independent magnets 27, which is a flat region where the magnetic flux density does not change. Therefore, the phase difference PS caused by the rotation direction is large.

[0077] Furthermore, similar to the third comparative example, since the long axis of the power generation sensor 13 is radial, there is a technical problem that the size of the detection device becomes larger.

[0078] On the other hand, in this comparative example, a general-purpose 2-pole magnet that can be magnetized by a hollow coil can be used as a standalone magnet 27, thus reducing magnet cost. Furthermore, it has the advantage of being able to use the same magnet 27 structure for detection devices of different sizes.

[0079] However, the assembly process is cumbersome and consequently increases the assembly cost, as it requires the individual magnets 27 to be oriented and fixed on the support substrate 26 so that the magnetic pole boundary line 27a, which is practically unidentifiable, is along the circumferential tangential direction.

[0080] The structure of Patent Document 3 can be classified as the category of Comparative Example 4.

[0081] Figure 5A and Figure 5B This refers to a rotation detection device 5, which is an example of a motion detection device according to an embodiment of the present invention. Figure 5C This represents the change in magnetic flux density relative to the rotation angle.

[0082] The rotation detection device 5 includes: a first support 51; a second support 52 that moves relative to the first support 51; a power generation sensor 100 supported on the first support 51; and a magnetic field generating source 400 supported on the second support 52.

[0083] In this embodiment, the first support 51 is a support substrate, on which the power generation sensor 100 is supported. In this embodiment, the second support 52 is an annular support substrate that rotates about the rotation axis 40. The magnetic field generating source 400 includes a plurality of (two in this embodiment) independent magnets M1, M2 arranged circumferentially at intervals on the second support 52.

[0084] The power generation sensor 100 includes a magnetic wire 110, a coil 120 wound around the magnetic wire 110, and a pair of L-shaped magnetic flux conducting sheets 130 and 131 respectively attached to both ends of the magnetic wire 110, configured to support the second support body 52 side ( Figure 5B The lower side) is designated as the detection area 140. A specific structural example of the power generation sensor 100 will be referred to... Figure 6A and Figure 6B This will be explained later.

[0085] The axial center position 113, which is the axial center position of the magnetic conductor 110, is offset radially from the rotation axis 40, and the axial x of the magnetic conductor 110 is along the circumference around the rotation axis 40 (more specifically, on the circumference around the rotation axis 40 through the axial center position 113 of the magnetic conductor 110, tangential direction at the axial center position 113).

[0086] Two independent magnets, M1 and M2, are magnetized in a direction parallel to the rotation axis 40 and are arranged at equal intervals (i.e., 180-degree angular intervals) around the circumference of the rotation axis 40. One of the two independent magnets, M1 and M2, is configured such that its N pole n1 is opposite to the power generation sensor 100 and is fixed to the second support body 52 when it approaches the power generation sensor 100, and the other is configured such that its S pole s1 is opposite to the power generation sensor 100 and is fixed to the second support body 52 when it approaches the power generation sensor 100. When the second support body 52 rotates around the rotation axis 40, each magnetic pole n1 and s1 moves along the circumferential track 30.

[0087] Thus, the magnetic field source 400 has multiple magnetic poles n1 and s1 disposed on the second support 52. These multiple magnetic poles n1 and s1 sequentially enter the detection area 140 along a track 30 substantially parallel to the axial direction x of the magnetic wire 110 when the second support 52 rotates relative to the first support 51 (an example of relative movement). At this time, magnetic poles n1 and s1 of different polarities alternately face the power generation sensor 100 through gaps 31. Since the individual magnets M1 and M2 are magnetized in a direction parallel to the rotation axis 40, the magnetic flux direction of each magnetic pole n1 and s1 is perpendicular to the direction of movement of that magnetic pole n1 and s1, and when facing the power generation sensor 100, it is the direction of intersection with the magnetic wire 110, that is, the opening direction (gap direction) of the gap 31 between the magnetic poles n1 and s1 and the power generation sensor 100.

[0088] The spacing λ between the multiple magnetic poles n1 and s1 on track 30, i.e., the circumferential spacing between adjacent magnetic poles n1 and s1, is longer than the total length Lw of the magnetic conductor 110 (refer to...). Figure 6BMore specifically, in this example, the spacing λ is more than 1.5 times the total length Lw of the magnetic conductor 110. Furthermore, the length α (along the length of the track 30) of the magnetic poles n1 and s1 on the track 30 is shorter than the total length Lw of the magnetic conductor 110, and is less than 50% of the spacing λ. In this example, the length α of the magnetic poles n1 and s1 on the track 30 is less than half the total length Lw of the magnetic conductor 110.

[0089] When the second support 52 rotates counterclockwise (CCW) together with the two independent magnets M1 and M2, 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 second support 52 rotates counterclockwise (CCW) together with the two independent magnets M1 and M2, 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 5C As shown, a negative pulse NP is generated near 90 degrees, and a positive pulse PP is generated near 270 degrees.

[0090] Similarly, when the second support 52 rotates clockwise (CW) together with the two independent magnets M1 and M2, 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. Furthermore, when the second support 52 rotates clockwise (CW) together with the two independent magnets M1 and M2, 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 5C As shown, a positive pulse PP is generated near 90 degrees, and a negative pulse NP is generated near 270 degrees.

[0091] Near 90 degrees and 270 degrees, the change in magnetic flux density relative to the rotation angle is very abrupt. Therefore, the deviation in pulse generation position is small, and the phase difference PS, the offset of the pulse generation position corresponding to the rotation direction, is extremely small. Furthermore, since the angular difference between the operating magnetization and the stabilizing magnetic field is very small, the range of so-called pulse loss (reversal range) is narrow when the direction of movement (rotation direction) is reversed.

[0092] Furthermore, since the major axis of the power generation sensor 100 is tangential to the circumference, the overall size of the rotation detection device 5 can be reduced. From another perspective, the diameter of the hollow portion of the second support 52 can be increased. Moreover, universal individual magnets M1 and M2, which can be manufactured by magnetizing hollow coils in the thickness direction, can be used, thus reducing magnet costs. Of course, the same design of individual magnets M1 and M2 can be used universally in rotation detection devices of different sizes, thus eliminating the need for specially designed magnets. Furthermore, since the N or S poles of the individual magnets M1 and M2, magnetized in the thickness direction, are simply fixed to the second support 52 with their N or S poles facing in one direction, the assembly process is simpler compared to the fourth comparative example, which requires aligning the magnetic pole boundaries radially, thus reducing assembly costs.

[0093] As mentioned earlier, the spacing λ between the multiple magnetic poles n1 and s1 on the track 30 is longer than the total length of the magnetic conductor 110 (preferably more than 1.5 times), therefore... Figure 5C As shown, a flat region with zero magnetic flux density appears in the intermediate region between 90 degrees and 270 degrees where the pulse is generated. This allows the influence of the magnetic fields from adjacent magnetic poles n1 and s1 on track 30 to be separated, causing a sharp change in magnetic flux density near 90 degrees and 270 degrees. This trend is further enhanced by setting the length α of magnetic poles n1 and s1 on track 30 to less than 50% of the pole configuration interval λ.

[0094] Furthermore, as described above, the lengths α of the magnetic poles n1 and s1 on track 30 are shorter than the total length of the magnetic conductor 110. This ensures that rapid changes in magnetic flux density can be achieved near 90 degrees and 270 degrees without creating flat areas during these changes. Setting the lengths α of the magnetic poles n1 and s1 to less than half the total length of the magnetic conductor 110 allows for more rapid changes in magnetic flux density, which is therefore preferable.

[0095] Figure 6A This is a perspective view illustrating an example of the structure of the power generation sensor 100. Figure 6B From Figure 6A The front view is viewed in the direction of arrow 101. The power generation sensor 100 moves relative to the magnetic pole 401 of the magnetic field generating source 400 (e.g., an independent magnet), thereby generating a pulse signal. The relative movement between the power generation sensor 100 and the magnetic field generating source 400 is achieved by the movement of at least one of the power generation sensor 100 and the magnetic field generating source 400. The following description primarily focuses on an example where relative movement is achieved by the movement of the magnetic field generating source 400.

[0096] The power generation sensor 100 includes a magnetic wire 110 exhibiting the large Backhausen effect, a coil 120 wound around the magnetic wire 110, and a pair of flux-conducting sheets 130, 131 having soft magnetic components. The coil 120 is wound around the magnetic wire 110 such that a first end 111 and a second end 112 of the magnetic wire 110 are exposed at the same length. In this embodiment, the coil 120 is wound around the magnetic wire 110 between the pair of flux-conducting sheets 130, 131. The pair of flux-conducting sheets 130, 131 are magnetically coupled to the first end 111 and the second end 112 of the magnetic wire 110, respectively.

[0097] A pair of flux-conducting plates 130 and 131 have substantially the same shape and size. More specifically, the pair of flux-conducting plates 130 and 131 are configured to be mutually symmetrical with respect to a plane of symmetry 115 (an imaginary plane used to illustrate the geometric configuration) orthogonal to the axial x-axis (length direction, line length direction) at the center position (hereinafter referred to as the "axial center position") 113 of the magnetic conductor 110. The pair of flux-conducting plates 130 and 131 include: axially orthogonal portions 133 extending parallel to each other from both ends 111 and 112 of the magnetic conductor 110 along an axially orthogonal direction z orthogonal to the axial x-axis; and axially parallel portions 134 extending from the front end of the axially orthogonal portions 133 in a direction approaching each other along the axial x-axis.

[0098] The two ends 111 and 112 of the magnetic wire 110 are respectively fixed to the base end of the axially orthogonal portion 133 of a pair of magnetic flux conducting plates 130 and 131. More specifically, wire arrangement portions 130a and 131a formed by holes or slots extending along the axial x are provided at the base end of the axially orthogonal portion 133. Figure 6A Examples of wire arrangement portions 130a and 131a consisting of holes are shown. When the wire arrangement portions 130a and 131a are consisting of grooves, these grooves are preferably grooves extending in the orthogonal direction z to open to an end face opposite to the detection area 140 described later. The first end 111 and the second end 112 of the magnetic wire 110 are fixed to the orthogonal portion 133 in the wire arrangement portions 130a and 131a, passing through the orthogonal portion 133. More specifically, the ends 111 and 112 of the magnetic wire 110 are fixed to the orthogonal portion 133 and coupled to each other by distributing resin (not shown) in the holes or grooves constituting the wire arrangement portions 130a and 131a. Thus, the magnetic wire 110 and the pair of flux-conducting sheets 130 and 131 are mechanically coupled to each other and magnetically coupled to each other.

[0099] The approach ends 134a of the axially parallel portions 134 of a pair of flux-conducting plates 130 and 131 are positioned opposite each other, sandwiching a plane of symmetry 115 passing through the axial center position 113 of the magnetic wire 110. That is, their approach ends 134a are spaced apart from each other in the axial x direction. The midpoint of this interval in the axial x direction corresponds to the position of the axial center position 113 in the axial x direction, so the distance from the approach ends 134a of the pair of axially parallel portions 134 to the plane of symmetry 115 in the axial x direction is equal. The distance L in the axial x direction is set to 5% to 50% of the distance D between the pair of axially orthogonal portions 133 at the coupling position of the magnetic wire 110 and the axially orthogonal portions 133, more preferably 20% to 40%. More specifically, the distance D is the distance in the axial x direction between the inner surfaces 130b and 131b (inner surfaces of the axially orthogonal portions 133) of the pair of flux-conducting plates 130 and 131 facing each other along the axial x direction at the coupling position with the magnetic wire 110.

[0100] The soft magnetic components constituting the flux-conducting sheets 130 and 131 are made of a material with a coercivity less than or equal to that of the magnetic conductor 110 and a relative permeability of 500 or higher. This material exhibits characteristics such as low magnetic resistance, low hysteresis, and low self-induction. Therefore, even when a high-frequency alternating magnetic field is applied, generated when the magnetic field source 400 moves at high speed, the impact on the output characteristics of the power generation sensor 100 is minimal. Specifically, the soft magnetic components are preferably made of Ni-based ferrite or Mn-based ferrite materials.

[0101] The power generation sensor 100 is configured such that a detection region 140 is defined on the side opposite to the magnetic wire 110 relative to the axial parallel portion 134. A magnetic field source 400 that generates the magnetic field to be detected is disposed in this detection region 140. The power generation sensor 100 and the magnetic field source 400 are disposed with a gap 31 having an axial orthogonal direction z. This gap 31 can be a complete air gap, for example, a printed circuit board 45 constituting, for example, the first support 51 can be mounted thereon. That is, the power generation sensor 100 can be disposed on one main surface of the printed circuit board 45, and the magnetic field source 400 can be disposed on the other main surface. Electrical and / or electronic components can also be mounted on one or both main surfaces of the printed circuit board 45. In a specific example, the power generation sensor 100 is mounted on one main surface of the printed circuit board 45.

[0102] Typically, the magnetic field 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 the movement path of the magnetic field source 400. In this embodiment, the magnetic field source 400 is composed of a plurality of independent magnets magnetized in the axial orthogonal direction z. Thus, the magnetic field source 400 has a plurality of magnetic poles 401 opposite to the power generation sensor 100 (more specifically, the axially parallel portion 134) when moving along the track 30 passing through the detection region 140.

[0103] In this embodiment, multiple magnetic poles 401 are configured such that, when the second support 52 moves relative to the first support 51 (printed substrate 45), magnetic poles 401 of different polarities alternately face the power generation sensor 100. Based on the change in the magnetic field generated as the magnetic poles 401 move through the detection area 140, the power generation sensor 100 outputs a pulse voltage. By processing and counting this pulse voltage, a position detection device for generating position information, i.e., an encoder (an example of a motion detection device), can be constructed.

[0104] The direction of movement of the magnetic pole 401 in the detection area 140, i.e., the direction of motion, is along the axial direction x. That is, it is approximately parallel to the magnetic wire 110. In other words, the track 30 has a portion in the detection area 140 that is substantially parallel to the axial direction x. In one specific example, the track 30 has a straight portion in the detection area 140 that is parallel to the axial direction x. The track 30 as a whole can be straight or it can have a curved portion. In another specific example, the track 30 has an arc portion in the detection area 140 that is tangent to the axial direction x. This arc portion can be located on the rotation axis 40, which is parallel to the orthogonal direction z of the axial direction. The track 30 as a whole can be an arc portion, i.e., circumferential. In addition, the track 30 can also have non-arc-shaped portions such as straight portions or elliptical portions. Figure 5A and Figure 5B In the example shown, track 30 is circular.

[0105] A pair of magnetic flux conduction plates 130, 131 are configured to correct the magnetic field generated by the magnetic field generator 400 disposed in the detection area 140 in the space containing the magnetic flux conduction plates 130, 131 into an axial x magnetic field and apply it to the magnetic wire 110.

[0106] More specifically, the flux-conducting plates 130 and 131, composed of soft magnetic material components, have an axially orthogonal portion 133 and an axially parallel portion 134, both approximately cuboid in shape. The axially parallel portion 134 is connected to the end, i.e., the front end, of the axially orthogonal portion 133 on the side opposite to the magnetic field source 400, i.e., on the side of the detection area 140. The flux-conducting plates 130 and 131 have an L-shape bent at a right angle at the connection between the axially orthogonal portion 133 and the axially parallel portion 134. The axially parallel portion 134 extends along the axial x-axis to cover the magnetic wire 110, i.e., to shield between the magnetic wire 110 and the detection area 140. The axially parallel portions 134 of a pair of flux-conducting plates 130 and 131, which have mutually symmetrical shapes, extend to the axial center side of the magnetic wire 110, and their approach ends 134a are spaced apart and face each other near the axial center position 113 of the magnetic wire 110. The approach end 134a forms a plane orthogonal to the x-axis. The two planes forming the two approach ends 134a are parallel to each other and are opposite each other in the x-axis. The distance L between the two approach ends 134a in the x-direction is the distance between the two planes forming the two approach ends 134a.

[0107] The flux-conducting sheets 130 and 131, and the coil 120, which are made of soft magnetic materials, are fixed to the housing (not shown) covering them by adhesive resin, fitting, or other suitable fixing methods. As described above, the two ends 111 and 112 of the magnetic wire 110 are fixed to the wire arrangement portions 130a and 131a, which are formed by two through holes or slots, by resin (not shown). Therefore, the power generation sensor 100 is composed of a structure in which a pair of flux-conducting sheets 130 and 131, the coil 120, and the magnetic wire 110 are fixed to each other and integrated.

[0108] The two ends of the coil 120 can be connected to external electrodes provided on the axial parallel portion 134. By soldering the external electrodes to a wiring conductor provided on a main surface of the printed circuit board 45, the power generation sensor 100 can be surface-mounted on the printed circuit board 45.

[0109] In the power generation sensor 100 configured as described above, the magnetic field of the detection region 140 is conducted to both ends 111 and 112 of the magnetic wire 110 through magnetic flux conducting sheets 130 and 131, which have soft magnetic components. Furthermore, since there is an axially parallel portion 134 parallel to the axial direction x of the magnetic wire 110 between the detection region 140 and the magnetic wire 110, the magnetic flux from the detection region 140 toward the axial middle portion (position along the axial direction) of the magnetic wire 110 is shielded by the axially parallel portion 134. In particular, when the axial x distance L between the proximal ends 134a of the axially parallel portions 134 of the pair of magnetic flux conducting sheets 130 and 131 is set to 5% to 50% of the distance D between the axially orthogonal portions 133 at the junction position of the magnetic wire 110, excellent magnetic shielding effect can be obtained. Therefore, since a magnetic field along the axial x direction can be applied over a large range along the magnetic wire 110, the large Backhausen effect can be sufficiently induced, and a high output signal can be obtained.

[0110] Furthermore, since the power generation sensor 100 includes magnetic flux conducting plates 130 and 131, and these plates are fixed and coupled to the magnetic wire 110, the magnetic field generating source 400 (typically a magnet) serving as the detection medium can be disposed in the detection area 140. Therefore, it is easy to combine with magnetic field generating sources 400 having different shapes and / or polarities.

[0111] When the power generation sensor 100 moves relative to the magnetic field generator 400, the magnetic pole 401 of the magnetic field generator 400 moves along the track 30 passing through the detection area 140. This track 30 includes a straight section parallel to the axial direction x within the detection area 140, or an arc section with a tangent parallel to the axial direction x within the detection area 140. Therefore, when the magnetic pole 401 passes through the detection area 140, it is aligned with the axially parallel section 134, and the magnetic flux generated by the magnetic pole 401 is applied to the magnetic wire 110 through the magnetic flux conductive sheets 130 and 131.

[0112] Since the axially parallel portions 134 of the flux-conducting plates 130 and 131 extend along the axial x-axis of the magnetic wire 110, their magnetic shielding effect makes it difficult for magnetic flux to enter the axial middle portion of the magnetic wire 110 from the magnetic pole 401. The axially parallel portions 134 extending along the axial x-axis of the magnetic wire 110 can collect a large amount of magnetic flux. Therefore, even if the magnetic flux generated from the magnetic pole 401 is weak, a magnetic field required to exhibit the large Barkhausen effect can be applied to the magnetic wire 110. Furthermore, the axially parallel portions 134 can be opposite the magnetic pole 401 over a wide range within the detection area 140, and suppress the entry of magnetic flux into the axial middle portion of the magnetic wire 110.

[0113] Therefore, with the magnetic pole 401 opposite to the axial center 113 of the magnetic wire 110, the magnetic flux conducted from the pair of magnetic flux conducting plates 130 and 131 to the two ends 111 and 112 of the magnetic wire 110 is in equilibrium. Starting from this state, if the magnetic pole 401 moves slightly in either direction along the track 30, the magnetic flux density within the magnetic wire 110 will change drastically. Thus, the change in magnetic flux density relative to the positional variation of the magnetic pole 401 becomes steep.

[0114] Figure 7A This is a perspective view illustrating a specific structural example of the rotation detection device 5A. Figure 7B This is its top view. Furthermore, Figure 7C From Figure 7B The front view of the structure near the power generation sensor 100 is shown from the right side.

[0115] The rotation detection device 5A is an example of an encoder that detects rotational position about a rotation axis 40 that coincides with the central axis of the rotation axis 50. The rotation detection device 5A includes a power generation sensor 100 and a magnetic field generator 400. In this example, the rotation detection device 5A also includes a sensor 55 (e.g., a magnetic sensor). Although not shown, the rotation detection device 5A may further include: a counting processing circuit that processes and counts the pulse output generated by the power generation sensor 100; and a non-volatile memory that stores the counting results of the counting processing circuit. The counting processing circuit can be configured to perform the counting operation while taking into account the output of the sensor 55.

[0116] The power generation sensor 100 is disposed on and supported by the first support body 51. In this embodiment, the first support body 51 also carries a sensor 55.

[0117] The magnetic field source 400 is fixed to the second support 52. The second support 52 is movable relative to the first support 51. Specifically, the second support 52 is coupled (fixed) to the rotation axis 50 and rotates together with the rotation axis 50 about the rotation axis 40. Therefore, the second support 52 can be part of a rotating body. In contrast, the first support 51 is fixed and remains in a non-rotating state. Thus, the magnetic field source 400 rotates together with the second support 52 about the rotation axis 40 and moves relative to the first support 51.

[0118] Typically, the rotating shaft 50 is rotated by a driving force from a drive shaft of an electric motor (not shown). When the motor is driven bidirectionally, the rotating shaft 50 rotates accordingly in both the counter-clockwise (CCW) and clockwise (CW) directions. The first support 51 may be a printed circuit board 45 arranged along a plane orthogonal to the rotation axis 40.

[0119] In this example, the magnetic field source 400 comprises multiple, specifically 2k (k=2 in the example) independent magnets M1, M2, ..., which are fixed to the second support 52. The independent magnets M1, M2, ... are magnetized along a direction parallel to the rotation axis 40, i.e., the axial orthogonal direction z, and are arranged at equal angular intervals around the rotation axis 40. In this example, the independent magnets M1, M2, ... are plate-shaped (more specifically, circular plates) magnetized along their thickness direction, but their shapes are not limited to this. They could also be... Figure 6A The rectangular or rectangular plate shape shown can also be a magnet with an arc shape (specifically a fan shape with the radial inner part cut off) when viewed from above.

[0120] Viewed from above, parallel to the axis of rotation 40 (see reference) Figure 7B The N poles n1, n2, ... and the S poles s1, s2, ... are arranged alternately in the circumferential direction. That is, the second support 52 rotates in one direction around the rotation axis 40, so that magnetic poles of different polarities, namely N poles and S poles, alternately enter the detection area 140 of the power generation sensor 100 (refer to...). Figure 7C An alternating magnetic field is generated near the power generation sensor 100.

[0121] The power generation sensor 100 is mounted on a main surface of the first support 51 (printed substrate 45). The magnetic wire 110 of the power generation sensor 100 is located on a tangent to the circumference of a circle centered on the rotation axis 40, and the axial center position 113 of the magnetic wire 110 is located at the point of tangency of this tangent. The power generation sensor 100 is configured such that the magnetic force conducted from the two flux-conducting plates 130 and 131 is balanced when any center of one of the independent magnets M1, M2, ..., i.e., the plurality of magnetic poles n1, n2, ..., nk; s1, s2, ..., sk is aligned with the axial center position 113 of the magnetic wire 110.

[0122] The axially parallel portion 134 of the flux-conducting plates 130 and 131 forms a detection area opposing surface 134b on the detection area 140 side, which is opposite to the detection area 140. The detection area opposing surface 134b is a flat surface parallel to the axial direction x. When a magnetic pole is disposed in the detection area 140, the detection area opposing surface 134b forms a flux-conducting end that guides the magnetic flux from the magnetic pole into the interior of the flux-conducting plates 130 and 131.

[0123] The axial parallel portions 134 of the magnetic flux conducting sheets 130 and 131 are soldered to a wiring pattern (not shown) formed on a main surface of the first support 51 (printed circuit board 45), thereby mounting the power generation sensor 100 onto the first support 51 (printed circuit board 45). The power generation sensor 100 is configured such that the axial x of the magnetic wire 110 is tangent to a point (tangent point) on the circumference centered on the rotation axis 40, and the axial center position 113 of the magnetic wire 110 coincides with this tangent point. The detection area 140 of the power generation sensor 100 is located on the side opposite to the magnetic wire 110 relative to the axial parallel portions 134, which in this example is the area on the other main surface side of the first support 51 (printed wiring board 45).

[0124] In this example, the second support 52 is configured as an annulus surrounding the rotation axis 40. More specifically, the second support 52 is composed of an annular plate-like body, arranged along a plane orthogonal to the rotation axis 40, and parallel to the first support 51 (printed substrate 45). In the second support 52, a plurality of independent magnets M1, M2, ... are fixed on the surface opposite to the other main surface of the first support 51 (printed substrate 45). In this embodiment, the plurality of independent magnets M1, M2, ... are arranged at equal intervals circumferentially around the rotation axis 40. In the specific example illustrated, four independent magnetic poles M1, M2, M3, M4 are arranged at 90-degree angular intervals around the rotation axis 40, and they are fixed to the second support 52 in a manner opposite to the first support 51 (printed substrate 45). The distance from the rotation axis 40 to the center of the independent 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 the top view along the rotation axis 40, the magnetic wire 110 and the independent magnets M1, M2, ... are located on a circle with equal radius around the rotation axis 40 as the central axis, thus achieving a relative positional relationship in a direction parallel to the rotation axis 40. The second support 52 is preferably a yoke made of a soft magnetic material.

[0125] The second support 52 rotates together with the rotation axis 50 around the rotation axis 40, thereby allowing the independent magnets M1, M2, ... to move about the rotation axis 40 on the circular track 30 passing through the detection area 140. The axial x-axis of the magnetic conductor 110 is parallel to the tangent at a point (tangent point) on the circular 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) at that tangent point. In other words, the axial center position 113 of the magnetic conductor 110 is located at a point (tangent point) on the circumference of a circle centered on the rotation axis 40 and with a radius equal to that of the circular track 30, and the magnetic conductor 110 moves along the tangent at that tangent point.

[0126] The distance between the first support 51 and the second support 52 along the rotation axis 40 is set such that the rotation of the second support 52 allows the independent magnets M1, M2, ... to enter the detection area 140 of the power generation sensor 100.

[0127] In the printed circuit board 45 constituting the first support 51, a sensor 55, for example a magnetic sensor, is also mounted on the main surface on which the power generation sensor 100 is mounted. Other electrical or electronic components, such as the aforementioned counting processing circuit and non-volatile memory, may also be mounted on the main surface of the printed circuit board 45.

[0128] Sensor 55 is configured to detect the polarity of a magnetic pole opposite to the central portion of the power generation sensor 100. Sensor 55 is, for example, a magnetic sensor such as a Hall IC. When it detects an N pole (i.e., when the N pole is opposite to the central portion of the power generation sensor 100), it outputs an H signal; when it detects an S pole (i.e., when the S pole is opposite to the central portion of the power generation sensor 100), it outputs an L signal. Thus, sensor 55 determines the polarity of magnetic poles passing in its vicinity, and as a result, outputs an identification signal that identifies the polarity of the magnetic pole opposite to the central portion of the power generation sensor 100. In this embodiment, sensor 55 is configured to detect magnetic poles at a position 180 degrees phase-differential about the rotation axis 40 relative to the power generation sensor 100, i.e., a position symmetrical about the rotation axis 40. When k is an even number (e.g., 2), sensor 55 detects a magnetic pole with the same polarity as the magnetic pole opposite to the central portion of the power generation sensor 100. When k is an odd number (e.g., 3), sensor 55 detects a magnetic pole with the opposite polarity to the magnetic pole opposite to the central portion of the power generation sensor 100. In either case, sensor 55 can detect the polarity of the magnetic pole opposite the central part of the power generation sensor 100.

[0129] With this structure, by rotating the CCW counterclockwise around the rotation axis 40, each time a magnetic pole pair n1, s1; n2, s2; ...; nk, sk passes through the detection area 140 along the circular track 30, a negative pulse NP and a positive pulse PP are generated sequentially (see reference). Figure 5C Additionally, by rotating counterclockwise CW around the rotation axis 40, each time a magnetic pole pair n1, s1; n2, s2; ...; nk, sk passes through the detection area 140 along the circular track 30, a positive pulse PP and a negative pulse NP are generated sequentially (see reference). Figure 5C Then, based on these pulses and the sensor 55 which outputs an identification signal representing the polarity of the magnetic poles on the circular track 30 between the magnetic flux conduction plates 130 and 131, the rotational position and rotational direction can be identified.

[0130] Specifically, when the sensor 55 detects the N pole when a negative pulse NP is generated, and when the sensor 55 detects the S pole when a positive pulse PP is generated, the rotation direction can be identified as counterclockwise (CCW). On the other hand, when the sensor 55 detects the N pole when a positive pulse PP is generated, and when the sensor 55 detects the S pole when a negative pulse NP is generated, the rotation direction can be identified as clockwise (CW).

[0131] and Figure 6A and Figure 6B Similarly, in the structure shown, the spacing λ between the multiple magnetic poles on track 30 is longer than the total length of magnetic wire 110. In this example, the spacing λ is more than 1.5 times the total length Lw of magnetic wire 110. Furthermore, the length α of the magnetic poles on track 30 (the length along track 30) is shorter than the total length Lw of magnetic wire 110, and is less than 50% of the spacing λ. In this example, the length α of the magnetic poles on track 30 is less than half the total length Lw of magnetic wire 110.

[0132] Through this structure, it is possible to achieve... Figure 6A and Figure 6B The structure shown has the same effect.

[0133] Figure 8 This is a top view illustrating the structure of a rotation detection device 6, an example of a motion detection device according to other embodiments of the present invention.

[0134] The rotation detection device 6 includes: a first support 51A; a second support 52A that moves relative to the first support 51A; a power generation sensor 100 supported on the first support 51A; and a magnetic field generating source 400 supported on the second support 52A. In this embodiment, the first support 51A is a support substrate, with the power generation sensor 100 supported on one of its main surfaces. In this embodiment, the second support 52A is cylindrical and rotates about a rotation axis 40. The magnetic field generating source 400 includes a plurality (two in this embodiment) of independent magnets M1 and M2 arranged circumferentially at intervals on the outer peripheral surface of the second support 52A.

[0135] The power generation sensor 100 has the same characteristics as... Figure 6A The same structure is configured to include a magnetic wire 110, a coil 120 wound around the magnetic wire 110, and a pair of L-shaped magnetic flux conduction plates 130 and 131 respectively attached to the two ends of the magnetic wire 110, with the second support body 52A side (rotation axis 40 side) serving as the detection area 140. That is, the rotation detection device 6 is a radial gap type, wherein the direction in which the gap between the magnetic field generator 400 (independent magnet) and the power generation sensor 100 is open (gap direction) is radial.

[0136] The axial center position 113 of the magnetic conductor 110 is radially offset from the rotation axis 40, and the axial direction x of the magnetic conductor 110 is along the circumference around the rotation axis 40 (more specifically, the tangential direction at the axial center position 113 on the circumference of the rotation axis 40 passing through the axial center position 113 of the magnetic conductor 110). Two independent magnets M1 and M2 are magnetized radially (in the gap direction) orthogonal to the rotation axis 40 and are arranged at equal intervals of 180 degrees around the circumference of the rotation axis 40. One of the two independent magnets M1 and M2 is configured such that when it approaches the power generation sensor 100, its N pole n1 is opposite to the power generation sensor 100 and fixed to the second support 52A; the other is configured such that when it approaches the power generation sensor 100, its S pole s1 is opposite to the power generation sensor 100 and fixed to the outer circumferential surface of the second support 52A.

[0137] When the second support 52A rotates around the rotation axis 40, each magnetic pole n1, s1 moves along the circumferential track 30. Thus, the magnetic field source 400 has multiple magnetic poles n1, s1 disposed on the second support 52A. These multiple magnetic poles n1, s1 sequentially enter the detection area 140 along a track substantially parallel to the axial direction x of the magnetic conductor 110 as the second support 52A rotates relative to the first support substrate (an example of relative movement). At this time, magnetic poles n1, s1 of different polarities alternately face the power generation sensor 100 with gaps between them. Since the individual magnets M1, M2 are magnetized radially orthogonal to the rotation axis 40, the magnetic flux direction of each magnetic pole n1, s1 is perpendicular to the direction of movement of that magnetic pole n1, s1, and when facing the power generation sensor 100, it is in the direction intersecting the magnetic conductor 110, that is, the direction in which the gap between the magnetic poles n1, s1 and the power generation sensor 100 is open (gap direction).

[0138] The spacing λ between the multiple magnetic poles n1 and s1 on track 30 is longer than the total length of magnetic wire 110. More specifically, in this example, the spacing λ is more than 1.5 times the total length Lw of magnetic wire 110. Furthermore, the length α (along track 30) of the magnetic poles n1 and s1 on track 30 is shorter than the total length Lw of magnetic wire 110, and is less than 50% of the spacing λ. In this example, the length α of the magnetic poles n1 and s1 on track 30 is less than half the total length Lw of magnetic wire 110.

[0139] Based on this structure, it is also possible to achieve... Figure 6A and Figure 6B The structure shown has the same effect.

[0140] The embodiments of the present invention have been described above, but as shown in the following examples, the present invention may also be implemented in other forms.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] In addition, in the above embodiment, the axial orthogonal portion of the magnetic flux conduction sheet has a first portion extending from the magnetic wire 110 to the detection area 140 and a second portion extending from the magnetic wire 110 to the side opposite to the detection area 140. However, even if the second portion is omitted, it has no substantial impact on the magnetic flux conduction function (magnetic collection function).

[0145] In addition, various design changes may be made within the scope of the claims.

[0146] Label Explanation

[0147] 5, 5A, 6 Rotational Detection Device

[0148] 30 orbits

[0149] 31 gaps

[0150] 40 Rotation axis

[0151] 45 Printed substrate

[0152] 50 Rotation axis

[0153] 51, 51A First Support Body

[0154] 52, 52A Second Support

[0155] 55 Sensors

[0156] 100 power generation sensor

[0157] 110 Magnetic wire

[0158] 113 Axis center position

[0159] 115 Symmetry plane

[0160] 120 coil

[0161] 130, 131 Magnetic flux conduction sheet

[0162] 130a, 131a Conductor Configuration Section

[0163] 133 Axial Orthogonal Part

[0164] 134 Axial parallel section

[0165] 134a Proximity End

[0166] 140 Detection Area

[0167] 400 Magnetic Field Generator

[0168] 401 Magnetic Pole

[0169] Lw is the total length of the magnetic wire.

[0170] Independent magnets M1, M2, M3, and M4

[0171] PP positive pulse

[0172] NP negative pulse

[0173] PS phase difference

[0174] n1, n2 N poles (magnetic poles)

[0175] s1, s2 S poles (magnetic poles)

[0176] x-axis

[0177] z-axis orthogonal direction

[0178] λ pole spacing

[0179] α is the length of the 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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