Power generation device, rotation angle detector, and method for manufacturing power generation device

Abstract

Provided is a power generation device or the like capable of reducing individual differences and unevenness in magnetic flux density in power generation elements. This power generation device is provided with: a magnet (20) which is a circular ring-shaped magnet (20) centered on a rotation axis (A), is magnetized in the radial direction of the circular ring shape, and is disposed so as to be rotatable centered on the rotation axis (A); and a power generation element (24) that generates power by a change in the magnetic field accompanying the rotation of the magnet (20). The distance from the rotation axis (A) to the center of the power generation element (24) is equal to or greater than the radius of the inner diameter of the magnet (20) and equal to or less than the average value of the radius of the inner diameter and the radius of the outer diameter of the magnet (20).

Description

Technical Field

[0001] The present disclosure relates to a power generation device, a rotation angle detector, and a method for manufacturing the power generation device. Background Art

[0002] Conventionally, there are known power generation devices comprising a magnet and a power generation element, and rotation angle detectors utilizing such power generation devices. The magnet is a ring-shaped magnet that rotates about a rotation axis, and the power generation element comprises a magnetic wire and a coil. For example, Patent Document 1 discloses a rotation angle detector comprising a disk-shaped magnet mounted on a shaft and three power generation sections composed of magnetic wires and coils.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6336232 Summary of the Invention

[0006] In power generation devices used in the rotation angle detector described in Patent Document 1, individual variations in magnetic flux density occur within the power generation elements due to manufacturing and assembly errors among the various components. Furthermore, this nonuniformity in magnetic flux density within the power generation elements can reduce the stability of the power generation amount and the rotation angle during power generation (i.e., the rotation angle of the magnet relative to the power generation element). This individual variation and nonuniformity in magnetic flux density within the power generation elements can reduce the detection accuracy of the rotation angle detector used in the power generation device.

[0007] The present disclosure has been made to solve such a problem, and an object of the present disclosure is to provide a power generation device capable of reducing individual differences and non-uniformity in magnetic flux density in power generation elements, and a rotation angle detector using the power generation device.

[0008] A power generation device according to one embodiment of the present disclosure includes: a magnet having a ring shape centered on a rotation axis, magnetized in a radial direction of the ring shape, and arranged to be rotatable about the rotation axis; and a power generation element that generates power by a change in the magnetic field accompanying the rotation of the magnet. If the distance from the rotation axis to the center of the power generation element is r, and the radius of the inner diameter and the radius of the outer diameter of the magnet are R1 and R2, respectively, then a positional deviation rate ε representing the relative position of the center of the power generation element with respect to the magnet is defined by the following equation:

[0009] [Mathematical formula 1]

[0010]

[0011] Regarding the position deviation rate ε, -50≤ε≤0 holds true.

[0012] A rotation angle detector according to another aspect of the present disclosure includes the above-described power generation device and an address information acquisition unit that is driven by the electromotive force of the power generation element and acquires address information corresponding to the rotation angle of the magnet.

[0013] Another embodiment of the present disclosure is a method for manufacturing a power generation device, which is a method for manufacturing a power generation device including a magnet and a power generation element, wherein the magnet is a ring-shaped magnet centered on a rotation axis, is magnetized along the radial direction of the ring shape, and is arranged to be freely rotatable around the rotation axis, and the power generation element generates electricity by changes in the magnetic field accompanying the rotation of the magnet. The method for manufacturing the power generation device includes: a determination step of determining the position of the center of the power generation element based on the radius of the inner diameter and the radius of the outer diameter of the magnet; and a configuration step of configuring the power generation element and the magnet based on the position determined by the determination step. If the distance from the rotation axis to the center of the power generation element is set to r, and the radius of the inner diameter and the radius of the outer diameter are set to R1 and R2 respectively, the position deviation rate ε representing the relative position of the center of the power generation element with respect to the magnet is defined by the following formula:

[0014] [Mathematical formula 2]

[0015]

[0016] In the determining step, the position of the center of the power generating element is determined so that -50≤ε≤0 holds true with respect to the positional deviation rate ε.

[0017] The power generation device, rotation angle detector, and power generation device manufacturing method disclosed herein can provide a power generation device, rotation angle detector, and power generation device manufacturing method capable of reducing individual differences and nonuniformity in magnetic flux density in power generation elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic cross-sectional view showing the overall structure of the power generator and the rotation angle detector according to the first embodiment.

[0019] Figure 2 This is a schematic plan view showing the overall structure of the power generator and the rotation angle detector according to the first embodiment.

[0020] Figure 3 This is a diagram for explaining the definition of the angle corresponding to the relative position of the magnet and the power generating element according to the first embodiment.

[0021] Figure 4This is a plan view showing the positional relationship between the power generating element and the magnet of the power generating device according to the first embodiment.

[0022] Figure 5 This is a side view showing the positional relationship between the power generating element and the magnet of the power generating device according to the first embodiment.

[0023] Figure 6 FIG. 1 is a first diagram showing the relationship between the rotational position of the magnet and the distribution of the magnetic flux density in the longitudinal direction of the power generating element according to the first embodiment.

[0024] Figure 7 FIG. 2 is a second diagram showing the relationship between the rotational position of the magnet and the distribution of the magnetic flux density in the longitudinal direction of the power generating element according to the first embodiment.

[0025] Figure 8 FIG3 is a third diagram showing the relationship between the rotational position of the magnet and the distribution of the magnetic flux density in the longitudinal direction of the power generating element according to the first embodiment.

[0026] Figure 9 This is a graph showing the relationship between the position in the power generating element according to the first embodiment and the magnetic flux density at the start of power generation.

[0027] Figure 10 This is a first graph showing the relationship between the distance from the power generating element to the magnet and the difference in magnetic flux density according to the first embodiment.

[0028] Figure 11 This is a second graph showing the relationship between the distance from the power generating element to the magnet and the magnetic flux density difference according to the first embodiment.

[0029] Figure 12 This is a graph showing the relationship between the positional deviation rate of the power generation device according to the first embodiment and the average value of the magnetic flux density difference.

[0030] Figure 13 This is a graph showing the relationship between the positional deviation rate of the power generation device according to the first embodiment and the standard deviation of the magnetic flux density difference.

[0031] Figure 14 This is a flowchart showing the flow of the method for manufacturing the power generation device according to the first embodiment.

[0032] Figure 15 This is a schematic cross-sectional view showing the overall structure of a rotation angle detector according to the second embodiment.

[0033] Figure 16 This is a schematic plan view showing the structure of a magnet according to Modification 1.

[0034] Figure 17This is a schematic plan view showing the structure of a magnet according to Modification 2. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present disclosure. In addition, the embodiments described below each represent a specific example of the present disclosure. Therefore, the numerical values, structural elements, configuration positions and connection methods of the structural elements, and the processes and the order of the processes shown in the following embodiments are examples and do not limit the subject matter of the present disclosure. Therefore, among the structural elements in the following embodiments, the structural elements that are not recorded in the independent technical solutions representing the highest concept of the present disclosure are described as arbitrary structural elements.

[0036] In addition, each figure is a schematic diagram and does not necessarily illustrate the strict description. In addition, in each figure, the same reference numerals are given to substantially the same structures as in other figures, and repeated descriptions are omitted or simplified.

[0037] In addition, in this specification, terms such as equal and symmetrical that indicate the relationship between elements, and terms such as orthogonal, parallel, plate-shaped, circular, annular, cylindrical, disc-shaped, and arc-shaped that indicate the shape of elements, do not express only strict meanings, but rather mean that the range of being substantially the same also includes, for example, differences of a few percent.

[0038] (Implementation Method 1)

[0039] The power generation device, the rotation angle detector, and the method for manufacturing the power generation device according to the first embodiment will be described.

[0040] [1-1. Overall Structure of Power Generation Device and Rotation Angle Detector]

[0041] The overall structure of the power generation device and the rotation angle detector according to this embodiment is as follows: Figure 1 Provide explanation. Figure 1 : is a schematic cross-sectional view showing the overall structure of the power generation device 14 and the rotation angle detector 1 according to this embodiment. Figure 1 , a side view of the motor 2 to which the rotation angle detector 1 is mounted is also shown. Figure 2 Schematic top views showing the overall structure of the power generation device 14 and the rotation angle detector 1 according to this embodiment. Each figure shows mutually orthogonal X-axis, Y-axis, and Z-axis. The X-axis, Y-axis, and Z-axis form a right-handed orthogonal coordinate system.

[0042] like Figure 1 As shown, the motor 2 includes a main body 4, a rotor 6, a stator 8, a rotating shaft 10, and a housing 12. The rotor 6 and the stator 8 are housed in the main body 4. The rotor 6 rotates relative to the stator 8.

[0043] The rotating shaft 10 extends in the direction of the rotation axis and is a rod-shaped member such as a cylinder. Here, the rotation axis direction refers to the direction in which the rotation axis A, which serves as the rotation center of the rotating shaft 10, extends and is parallel to the Z-axis direction in each figure. The axis of the rotating shaft 10 coincides with the rotation axis A. The rotating shaft 10 is fixed to the rotor 6. For example, when power is supplied to the motor 2, the rotating shaft 10 rotates together with the rotor 6 based on the power with the rotation axis A as the rotation center. The rotation direction of the rotating shaft 10 coincides with the circumferential direction centered on the rotation axis A. A rotation angle detector 1 is provided at one end of the rotating shaft 10 in the direction of the rotation axis. A load (not shown) that is driven to rotate by the rotation of the rotating shaft 10 is mounted at the other end of the rotating shaft 10 in the direction of the rotation axis. For example, the rotating shaft 10 is formed of a magnetic metal such as iron.

[0044] The housing 12 is attached to the main body 4 so as to cover one end portion of the rotating shaft 10 in the rotation axis direction and the rotation angle detector 1. For example, the housing 12 is formed of a magnetic metal such as iron.

[0045] The rotation angle detector 1 is a detector for detecting the rotation of the rotating shaft 10. For example, the rotation angle detector 1 detects the rotation position of the rotating shaft 10, the rotation direction of the rotating shaft 10, and the rotation speed of the rotating shaft 10. As described above, the rotation angle detector 1 is provided at one end of the rotating shaft 10 in the direction of the rotation axis. Figure 1 as well as Figure 2 As shown, the rotation angle detector 1 includes a rotating plate 16, a substrate 18, a power generation device 14, and a detection unit 28. The power generation device 14 includes a magnet 20 and one or more power generation elements, namely, a power generation element 24 and a power generation element 26 (for the power generation element 26, see Figure 2 ).

[0046] The rotating plate 16 is a plate-shaped member extending perpendicularly to the rotation axis. Specifically, the rotating plate 16 is a circular plate with a main surface extending perpendicularly to the rotation axis, and has a circular shape when viewed in the direction of the rotation axis. The rotating plate 16 is attached to one end of the rotating shaft 10 in the direction of the rotation axis. The axis of the rotating plate 16 is aligned with the rotation axis A. The rotating plate 16 rotates together with the rotating shaft 10.

[0047] The base plate 18 is a plate-shaped member extending perpendicularly to the rotation axis. Specifically, the base plate 18 is a disc having a main surface extending perpendicularly to the rotation axis, and has a circular shape when viewed in the direction of the rotation axis. The base plate 18 is spaced apart from one end of the rotating shaft 10 and the rotating plate 16 in the direction of the rotation axis, and faces the rotating plate 16. The axis of the base plate 18 is aligned with the rotation axis A. The base plate 18 is fixed to the inner surface of the housing 12 and does not rotate with the rotating shaft 10.

[0048] The magnet 20 is annular in shape, centered around the rotation axis A. It is magnetized radially (i.e., in the radial direction) of the annular shape and is rotatably arranged about the rotation axis A. In this embodiment, the magnet 20 includes a first portion 21 with an inner S pole and an outer N pole, and a second portion 22 with an outer S pole and an inner N pole. With respect to a plane passing through the rotation axis A, one portion of the magnet 20 is the first portion 21, and the other portion of the magnet 20 is the second portion 22. In other words, the first portion 21 and the second portion 22 are symmetrically arranged with respect to the plane passing through the rotation axis A.

[0049] In this embodiment, the magnet 20 rotates together with the rotating shaft 10. Specifically, when the rotating shaft 10 rotates, the magnet 20 rotates together with the rotating shaft 10 and the rotating plate 16. Figure 1 As shown, the magnet 20 is arranged on the main surface of the rotating plate 16 facing the side opposite to the substrate 18 (that is, the main surface of the rotating plate 16 that is away from the substrate 18). The magnet 20 is arranged at a different position from the power generation element 24 and the power generation element 26 in the direction of the rotation axis. Figure 2 As shown, the magnet 20 overlaps with the base plate 18 when viewed in the direction of the rotation axis.

[0050] The magnet 20 has a plate-like shape with its thickness direction being the direction of the rotation axis. The magnet 20 has a main surface facing the power generating elements 24 and 26 and a main surface corresponding to the back surface of the main surface.

[0051] Power generation element 24 and power generation element 26 each generate electricity by utilizing changes in the magnetic field generated by magnet 20 rotating along with rotating shaft 10. Power generation element 24 and power generation element 26 are each disposed on the main surface of substrate 18 facing the side opposite to rotating plate 16. Power generation element 24 and power generation element 26 overlap substrate 18 when viewed in the direction of the rotation axis.

[0052] The power generation element 24 and the power generation element 26 are arranged at positions offset from the rotation axis A. That is, the power generation element 24 and the power generation element 26 do not overlap with the rotation axis A when viewed in the rotation axis direction.

[0053] The power generation element 24 and the power generation element 26 are arranged with a phase difference in the rotational direction of the rotating shaft 10. That is, the power generation element 24 and the power generation element 26 are arranged at different positions in the rotational direction of the rotating shaft 10. Furthermore, in a radial direction centered on the rotation axis A, the distances from the rotation axis A to the power generation element 24 and the power generation element 26 are equal. The detailed positional relationship between the power generation element 24 and the power generation element 26 and the magnet 20 will be described later.

[0054] The power-generating element 24 extends tangentially to the rotational direction centered on the rotation axis A (i.e., the rotational direction of the rotating shaft 10). In other words, the power-generating element 24 has an elongated shape, with its longitudinal direction tangential to the rotational direction centered on the rotation axis A. The power-generating element 24 is disposed on the principal surface of the substrate 18 facing away from the rotating shaft 10 (i.e., the principal surface of the substrate 18 facing away from the rotating plate 16). The power-generating element 24 includes a magnetically sensitive portion 30 and a coil 32 wound around the magnetically sensitive portion 30. In this embodiment, the power-generating element 24 also includes two magnetic flux collecting members 31.

[0055] The magnetic sensitive portion 30 is a magnetic member extending tangentially to the rotational direction centered on the rotation axis A. For example, the magnetic sensitive portion 30 is a magnetic member that produces a large Barkhausen effect due to changes in the external magnetic field and is a Wiegand wire extending tangentially to the rotational direction centered on the rotation axis A. A Wiegand wire is a magnetic member whose magnetization aligns in one direction along the length of the wire when a magnetic field exceeding a given value is applied along the length of the wire. When the direction of the magnetic flux flowing along the length of the Wiegand wire changes, the magnetization direction of the Wiegand wire suddenly reverses, inducing a voltage pulse at both ends of the coil 32 wound around the Wiegand wire. This generates electricity, and the output of the generating element 24 varies according to the change in the direction of the magnetic field in the generating element 24 as the magnet 20 rotates. The cross-section perpendicular to the length of the magnetic sensitive portion 30 is, for example, circular.

[0056] The magnetic collecting component 31 is an annular magnetic component into which the magnetic sensing part 30 is inserted, and has a magnetic collecting function. One of the two magnetic collecting components 31 is arranged between one end of the magnetic sensing part 30 and the coil 32. The other of the two magnetic collecting components 31 is arranged between the other end of the magnetic sensing part 30 and the coil 32. The magnetic collecting component 31 includes a soft magnetic material. The magnetic collecting component 31 has a lower coercive force than the magnetic sensing part 30. The magnetic collecting component 31 can also have a higher magnetic permeability and saturation magnetic flux density than the magnetic sensing part 30. In the present embodiment, the magnetic collecting component 31 is composed of ferrite.

[0057] The power generating element 26 extends in a tangential direction of the rotation direction centered on the rotation axis A. The power generating element 26 includes a magnetic sensitive portion 34 and a coil 36 wound around the magnetic sensitive portion 34 . In this embodiment, the power generating element 26 further includes two magnetic flux collecting members 35 .

[0058] The magnetic sensitive portion 34 is a magnetic body extending tangentially to the rotational direction centered on the rotation axis A. For example, the magnetic sensitive portion 34 is a magnetic body exhibiting a large Barkhausen effect and is a Wiegand wire extending tangentially to the rotational direction centered on the rotation axis A. The generating element 26 generates electricity in the same manner as the generating element 24 . The output of the generating element 26 changes according to changes in the direction of the magnetic field in the generating element 26 as the magnet 20 rotates.

[0059] The magnetism collecting member 35 is an annular magnetic member into which the magnetic sensing portion 34 is inserted, and has a magnetism collecting function. One of the two magnetism collecting members 35 is arranged between one end of the magnetic sensing portion 34 and the coil 36. The other of the two magnetism collecting members 35 is arranged between the other end of the magnetic sensing portion 34 and the coil 36. The magnetism collecting member 35 includes a soft magnetic material. The magnetism collecting member 35 has a lower coercive force than the magnetic sensing portion 34. The magnetism collecting member 35 may also have a higher magnetic permeability and a higher saturation magnetic flux density than the magnetic sensing portion 34. In the present embodiment, the magnetism collecting member 35 is made of ferrite.

[0060] The detection unit 28 is a processing unit that detects the rotation angle of the magnet 20 based on the outputs of the power generation elements 24 and 26. In this embodiment, the detection unit 28 is located on the main surface of the substrate 18 that faces the rotating plate 16 and is electrically connected to the power generation elements 24 and 26. For example, the detection unit 28 detects the rotation position of the magnet 20 (i.e., the rotation position of the rotating shaft 10) based on which of the power generation elements 24 and 26 is generating electricity. The method for detecting the rotation position is not limited to this. For example, the rotation position can be detected using a magnetic sensor activated by the power generation of the power generation elements 24 and 26, or by combining address information from these elements.

[0061] [1-2. Magnetic flux density in the power generation element]

[0062] The magnetic flux density in the power generating element 24 of the power generating device 14 according to the present embodiment is compared with the magnetic flux density in the power generating element 24 of the power generating device of the comparative example. Figures 3 to 8 Provide explanation. Figure 3 This is a diagram illustrating the definition of the angle θ corresponding to the relative positions of the magnet 20 and the power generating element 24 according to the present embodiment. Figure 4 as well as Figure 5 1 and 2 are a plan view and a side view respectively showing the positional relationship between the power generation element 24 and the magnet 20 of the power generation device 14 according to the present embodiment. Figure 4 as well as Figure 5 In FIG. 1 , a positive value indicates a position y to the right of the center 24 c in the longitudinal direction (Y-axis direction) of the power generating element 24 , and a negative value indicates a position y to the left of the center 24 c . Figures 6 to 81 is a diagram showing the relationship between the rotational position of the magnet 20 and the distribution of the magnetic flux density in the longitudinal direction of the power generating element 24 according to the present embodiment.

[0063] like Figure 3 As shown, when viewed in the direction of the rotation axis of the magnet 20, the length direction of the power generation element 24 ( Figure 3 The angle formed by the boundary line (in the Y-axis direction) between the first and second portions 21, 22 of the magnet 20 is set to angle θ corresponding to the relative position of the magnet 20 and the power generating element 24. Furthermore, when the direction of the boundary line between the first and second portions 21, 22 of the magnet 20 coincides with the longitudinal direction of the power generating element 24 and the power generating element 24 is located in the region of the second portion 22 of the magnet 20, angle θ is set to 0 degrees. In this embodiment, the center 24c of the power generating element 24 is defined by the central point of the magnetic sensitive portion 30. The central point of the magnetic sensitive portion 30 is defined by the centroid of a cross section perpendicular to the longitudinal direction of the magnetic sensitive portion 30. When the position of the power generating element 24 is fixed, angle θ increases as the magnet 20 rotates counterclockwise about the rotation axis A, and decreases as the magnet 20 rotates clockwise about the rotation axis A.

[0064] like Figure 4 As shown, the distance from the rotation axis A to the center 24c of the power generating element 24 is represented by r [mm]. In addition, the inner radius and outer radius of the magnet 20 are represented by R1 [mm] and R2 [mm], respectively.

[0065] like Figure 5 As shown, the distance from the power generating element 24 to the magnet 20 is d [mm]. In this embodiment, the distance d is the distance from the center 24c of the power generating element 24 to the center 20c of the magnet 20 in the rotation axis direction (ie, the Z-axis direction).

[0066] like Figure 6 As shown in (a), when the angle θ is -90 degrees, the magnetic sensitive portion 30 of the power generation element 24 overlaps with the region including the boundary between the first portion 21 and the second portion 22 of the magnet 20 when viewed from the rotation axis direction. Figure 6 As shown in (b), the magnetic flux density distribution in the longitudinal direction of the magnetic sensitive portion 30 does not have a peak in the longitudinal center of the magnetic sensitive portion 30 but is substantially uniform near the longitudinal center of the magnetic sensitive portion 30 .

[0067] like Figure 7 As shown in (a), the magnet 20 is Figure 6In the state shown in (a), when the angle θ is -180 degrees (in other words, +180 degrees) in the clockwise rotation, the magnetic sensitive portion 30 of the power generating element 24 overlaps the center portion of the north pole of the first portion 21 of the magnet 20 when viewed from the rotation axis.

[0068] At this time, if Figure 7 As shown in (b), the distribution of the magnetic flux density in the longitudinal direction of the magnetic sensitive portion 30 is smaller than Figure 6 The state (a) becomes a value close to 0.

[0069] like Figure 8 As shown in (a), the magnet 20 is Figure 7 When the state shown in (a) is further rotated clockwise and the angle θ reaches, for example, approximately +150 degrees (in other words, approximately −210 degrees), the power generation element 24 generates a power generation pulse.

[0070] At this time, if Figure 8 As shown in (b), the magnetic flux density distribution in the longitudinal direction of the magnetic sensitive portion 30 has a peak located near the longitudinal center of the magnetic sensitive portion 30 rather than at a position offset from the longitudinal center of the magnetic sensitive portion 30 .

[0071] Regarding the effect of the magnet 20 of the power generation device 14 according to this embodiment, Figure 9 Provide explanation. Figure 9 : is a schematic graph showing the relationship between the position y in the longitudinal direction (Y-axis direction) of the power generating element 24 according to the present embodiment and the magnetic flux density at the start of power generation.

[0072] like Figure 9 As shown in FIG. 1 , in the power generation device 14 according to this embodiment, the magnetic flux density distribution in the power generation element 24 is more uniform relative to the position y in the longitudinal direction (Y-axis direction) of the power generation element 24. Therefore, the magnetic sensitive portion 30 can be magnetized uniformly. Figure 9 As shown, in this embodiment, the symmetry of the distribution of the magnetic flux density at the start of power generation can be improved with respect to the center 24 c of the power generating element 24 , so that the magnetization of the entire magnetic sensitive portion 30 can be reversed substantially simultaneously at the start of power generation.

[0073] Furthermore, for example, by arranging the power generation element 24 on the rotation axis A, the uniformity of the magnetic flux density distribution can be improved. However, there are cases where the power generation element 24 cannot be arranged on the rotation axis A. Furthermore, when a plurality of power generation elements are arranged on the same plane perpendicular to the rotation axis A, as in the power generation device 14 according to the present embodiment, it is not possible to arrange all of the power generation elements on the rotation axis A.

[0074] As an indicator for evaluating the uniformity of the magnetic flux density distribution at the start of power generation in the power generation element 24 according to this embodiment, the magnetic flux density difference ΔT is used. Here, the magnetic flux density difference ΔT is obtained by dividing the two ends of the coil 32 of the power generation element 24 (the ends of the coil 32 and the ends of the coil 32) by the magnetic flux density difference ΔT. Figure 9 The difference in magnetic flux density at the positions y=y1 and y=y2 shown in the figure is defined as the difference in magnetic flux density at the start of power generation (corresponding to the positions y=y1 and y=y2 shown in the figure). Positions y=y1 and y=y2 at the longitudinal ends of the power generating element 24 are set, for example, at positions where the distance from the longitudinal ends of the coil 32 is between 0% and 10% of the length of the coil 32. If the magnetic flux density at position y=y1 is T1 [T] and the magnetic flux density at position y=y2 is T2 [T], the difference in magnetic flux density ΔT at the start of power generation is defined as T1 - T2.

[0075] [1-3. Positional Relationship between Power Generator and Magnet]

[0076] Regarding the positional relationship between the power generation element 24 and the magnet 20 of the power generation device 14 according to this embodiment, Figures 10 to 14 Provide explanation. Figure 10 : is a first graph showing the relationship between the distance d from the power generating element 24 to the magnet 20 and the magnetic flux density difference ΔT according to this embodiment. Figure 10 , the relationship is shown when the inner radius R1 of the magnet 20 is 8 mm and the outer radius R2 is 14.4 mm. Figure 11 : is a second graph showing the relationship between the distance d from the power generation element 24 to the magnet 20 and the magnetic flux density difference ΔT according to this embodiment. Figure 11 In FIG. 1 , the relationship is shown when the inner radius R1 of the magnet 20 is 9 mm and the outer radius R2 is 13.5 mm. Figure 10 as well as Figure 11 , each graph shows the case where the distance r from the rotation axis A to the center 24 c of the power generating element 24 is 4.4 mm, 4.8 mm, 5.2 mm, 5.6 mm, and 6.0 mm.

[0077] Figure 12 This graph shows the relationship between the positional deviation rate ε and the average value of the magnetic flux density difference ΔT of the power generation device 14 according to this embodiment. The positional deviation rate ε is a value indicating the relative position of the center 24c of the power generation element 24 with respect to the magnet 20. The positional deviation rate ε will be described later. Figure 12 The error bars shown indicate the standard deviation of each magnetic flux density difference ΔT. Here, the average value and standard deviation of the magnetic flux density difference ΔT are the average value and standard deviation of the magnetic flux density difference ΔT for six distances d from d=6 [mm] to d=9.5 [mm]. Figure 13Graph showing the relationship between the positional deviation rate ε of the power generation device 14 and the standard deviation of the magnetic flux density difference ΔT according to this embodiment. Figure 13 In FIG, an approximate curve obtained by approximating a quadratic polynomial is also shown by a dotted line.

[0078] like Figure 10 as well as Figure 11 As shown in the figure, when the distance r is 5.2 mm, the change of the magnetic flux density difference ΔT relative to the distance d is the smallest. Figure 10 as well as Figure 11 In the illustrated configuration example, by setting the distance r to approximately 5.2 mm, variations in the uniformity of the magnetic flux density within the power-generating element 24 can be suppressed in response to assembly errors in the power-generating element 24's position along its rotational axis. In other words, individual variations in the magnetic flux density within the power-generating element 24 due to manufacturing and assembly errors along its rotational axis can be reduced. Consequently, individual variations in the amount of power generated by the power-generating element 24 and the rotational angle at which power is generated can be reduced.

[0079] As described above, when the distance r is set to about 5.2 mm, the distance d from the power generation element 24 to the magnet 20 may be larger than the radius R1 of the inner diameter of the magnet 20. Figure 10 as well as Figure 11 As shown, the variation in magnetic flux density difference ΔT with respect to the distance d can be reduced. Therefore, individual differences in magnetic flux density in the power generating element 24 due to manufacturing errors and assembly errors in the rotation axis direction of the power generating element 24 can be reduced.

[0080] In addition, Figure 12 as well as Figure 13 The position deviation rate ε [%] representing the relative position of the center 24c of the power generating element 24 with respect to the magnet 20 is used. Figure 4 ), the position offset rate ε is the value of the relative position of the center 24c of the generating element 24 relative to the middle position (the circumference of the radius (R1+R2) / 2 centered on the rotation axis A) between the inner circumference (the circumference of the radius R1 centered on the rotation axis A) and the outer circumference (the circumference of the radius R2 centered on the rotation axis A) of the magnet 20, and is expressed by the following formula.

[0081] [Mathematical formula 3]

[0082]

[0083] In other words, the positional deviation ratio ε is the percentage of the ratio of the deviation amount of the center 24 c of the power generating element 24 from the intermediate position to the radial width ( R2 − R1 ) of the magnet.

[0084] like Figure 12 The error bars and Figure 13 As shown, when the positional deviation rate ε is between -50% and 0% (i.e., -50 ≤ ε ≤ 0), the standard deviation of the magnetic flux density difference ΔT can be reduced. In other words, when the distance r from the rotation axis A to the center 24c of the power-generating element 24 is greater than or equal to the inner radius R1 of the magnet 20 and less than or equal to the average of the inner radius R1 and the outer radius R2 of the magnet 20, the standard deviation of the magnetic flux density difference ΔT can be reduced. Therefore, variations in the uniformity of the magnetic flux density within the power-generating element 24 due to assembly errors in the position of the power-generating element 24 along the rotation axis can be suppressed. Consequently, individual variations in the amount of power generated and the rotational angle at which power is generated within the power-generating element 24 can be reduced.

[0085] Furthermore, when the positional deviation rate ε is between -30% and -10% (i.e., when -30 ≤ ε ≤ -10 holds), the standard deviation of the magnetic flux density difference ΔT can be further reduced. Consequently, variations in the uniformity of the magnetic flux density in the power-generating element 24 can be further suppressed in response to assembly errors in the position of the power-generating element 24 along the rotation axis.

[0086] like Figure 12 As shown, the absolute value of the magnetic flux density difference ΔT decreases as the positional deviation rate ε decreases, that is, as the distance r of the power generating element 24 from the rotation axis A decreases. Therefore, by reducing the positional deviation rate ε, the uniformity of the magnetic flux density in the power generating element 24 can be improved.

[0087] Furthermore, although the configuration of the power generating element 24 has been described above, the power generating element 26 may be configured in the same manner as the power generating element 24 .

[0088] [1-4. Method for manufacturing power generation device]

[0089] Regarding the method for manufacturing the power generation device 14 according to this embodiment, Figure 14 Provide explanation. Figure 14 This is a flowchart showing the flow of a method for manufacturing the power generation device 14 according to the present embodiment.

[0090] like Figure 14 As shown, first, the position of the center 24c of the power generating element 24 is determined based on the inner radius R1 and the outer radius R2 of the magnet 20 (determination step S10). In this step, the position of the center 24c of the power generating element 24 is determined so that -50 ≤ ε ≤ 0 holds true with respect to the positional deviation rate ε described above.

[0091] Next, the power generating element 24 and the magnet 20 are arranged based on the positions determined in the determination step S10 (arrangement step S20 ).

[0092] As described above, the power generation device 14 can be manufactured. According to the method for manufacturing the power generation device 14 of this embodiment, by using a magnet 20 that is annular and magnetized radially about the rotation axis A, the magnetic flux density distribution in the power generation element 24 can be made uniform. Furthermore, by arranging the power generation element 24 so that the positional deviation rate ε of the power generation element 24 is between -50% and 0%, variations in the uniformity of the magnetic flux density in the power generation element 24 can be suppressed due to assembly errors in the position of the power generation element 24 along the rotation axis. Consequently, individual differences in the amount of power generated by the power generation element 24 and the rotation angle at which power is generated can be reduced.

[0093] Furthermore, in the determination step S10, the position of the center 24c of the power-generating element 24 may be determined so that -30 ≤ ε ≤ -10 holds true for the positional deviation ratio ε. This further reduces the standard deviation of the magnetic flux density difference ΔT. Consequently, variations in the uniformity of the magnetic flux density within the power-generating element 24 can be further suppressed due to assembly errors in the position of the power-generating element 24 along the rotation axis.

[0094] (Implementation Method 2)

[0095] The rotation angle detector according to the second embodiment is described. The difference from the rotation angle detector 1 according to the first embodiment is that the rotation angle detector according to the second embodiment includes an address information acquisition unit driven by the power output from the power generation device 14 according to the first embodiment. Figure 15 Provide explanation.

[0096] Figure 15 : is a schematic cross-sectional view showing the overall structure of the rotation angle detector 1a according to this embodiment. Figure 15 , a side view of the motor 2 to which the rotation angle detector 1a is mounted is also shown.

[0097] The rotation angle detector 1a is a detector for detecting the rotation of the rotating shaft 10. The rotation angle detector 1a is provided at one end of the rotating shaft 10 in the direction of the rotation axis. Figure 15 As shown, the rotation angle detector 1a includes a rotating plate 16 , a substrate 18 , and a power generator 14 similarly to the rotation angle detector 1 according to Embodiment 1. The rotation angle detector 1a according to this embodiment further includes an address information acquisition unit 19 and a reflection pattern 17 .

[0098] The address information acquisition unit 19 is driven by the electromotive force of at least one of the power generation element 24 and the power generation element 26 to acquire address information corresponding to the rotation angle of the magnet 20. In the present embodiment, the address information acquisition unit 19 is arranged on the main surface of the substrate 18 facing the rotating plate 16. The address information acquisition unit 19 is opposite to the reflection pattern 17 in the direction of the rotation axis and emits light toward the reflection pattern 17. In addition, the address information acquisition unit 19 receives light reflected by the reflection pattern 17. The light reflected by the reflection pattern 17 changes according to the rotation position of the rotating shaft 10. The address information acquisition unit 19 detects the rotation amount of the rotating shaft 10 based on the light reflected by the reflection pattern 17. In the present embodiment, the address information acquisition unit 19 is equivalent to a light emitting element and a light receiving element.

[0099] Reflective pattern 17 is located on the main surface of rotating plate 16 facing substrate 18 and contains address information corresponding to the rotation angle of magnet 20. Reflective pattern 17 is annular and arranged along the rotation direction of rotating shaft 10. For example, reflective pattern 17 includes reflective areas that easily reflect light and non-reflective areas that are less likely to reflect light. These reflective and non-reflective areas form address information. For example, the reflective and non-reflective areas are arranged alternately in the rotation direction of rotating shaft 10.

[0100] In this embodiment, the address information acquisition unit 19 and the reflection pattern 17 constitute an optical encoder.

[0101] The rotation angle detector 1 a according to the present embodiment includes the address information acquisition unit 19 , and thus can detect the rotation angle with higher accuracy than the rotation angle detector 1 according to the first embodiment.

[0102] Furthermore, the rotation angle detector 1 a according to this embodiment may detect the rotation angle based not only on the address information acquired by the address information acquisition unit 19 but also on the outputs of the power generation elements 24 and 26 as in the first embodiment.

[0103] (Other Implementation Methods)

[0104] The power generation device, rotation angle detector, and power generation device manufacturing method described above are based on the embodiments of the present disclosure. However, the present disclosure is not limited to the aforementioned embodiments. The present disclosure also encompasses various modifications of the aforementioned embodiments that would occur to those skilled in the art, as well as implementations achieved by arbitrarily combining the structural elements and functions of the embodiments without departing from the spirit of the present invention.

[0105] For example, in the above embodiment, the magnet 20 has Figure 1 as well as Figure 2The shape shown in FIG. 1 is a diagram of a magnet according to a modification example. However, the structure of the magnet according to the present disclosure is not limited to such a structure. Figure 16 as well as Figure 17 Provide explanation. Figure 16 as well as Figure 17 These are schematic plan views showing the structures of the magnet 120 according to Modification 1 and the magnet 220 according to Modification 2, respectively.

[0106] like Figure 16 As shown, the magnet 120 according to Modification 1 includes a first portion 121 and a second portion 122. The first and second portions 121, 122 according to Modification 1 have an arc-shaped shape centered on the rotation axis A when viewed in the direction of the rotation axis. They differ from the first and second portions 21, 22 according to Embodiment 1 in that they are separated from each other. Like the first and second portions 21, 22 according to Embodiment 1, the first and second portions 121, 122 have a predetermined thickness in the direction of the rotation axis. Shapes in which only a portion of a circular ring is missing, as in the magnet 120 according to Modification 1, are also included in the annular shape. Furthermore, the annular shape also includes shapes that are not completely circular but are generally circular. For example, a magnet 120 in which the distance between one end of the first portion 121 and one end of the second portion 122, which is opposite to the first end, is considered annular in shape. The magnet 120 having such a structure also has the same effects as the magnet 20 according to the first embodiment.

[0107] like Figure 17 As shown, the magnet 220 according to Modification 2 includes a first portion 121, a second portion 122, and magnetic bodies 223 and 224. The magnetic bodies 223 and 224 have the same thickness as the first portion 121 and the second portion 122, for example, in the direction of the rotation axis. The magnetic bodies 223 and 224 connect the ends of the first portion 121 and the ends of the second portion 122, respectively. Specifically, the magnetic body 223 connects one end of the first portion 121 and one end of the second portion 122, while the magnetic body 224 connects the other end of the first portion 121 and the other end of the second portion 122. Magnet 220 having this structure also exhibits the same effects as the magnet 20 according to Embodiment 1. Furthermore, the magnet 220 according to Modification 2 easily maintains the magnetic flux density in the longitudinal direction of the power-generating elements 24 and 26. Furthermore, the magnetic permeability is easily increased, and a decrease in the magnetic flux density in the longitudinal direction of the power-generating elements 24 and 26 at high temperatures is easily suppressed. Therefore, it becomes easy to make the power generation element 24 and the power generation element 26 generate power appropriately.

[0108] In the above embodiment, the power generation device 14 includes two power generation elements, namely, the power generation element 24 and the power generation element 26. However, the power generation device 14 may also include a single power generation element or three or more power generation elements. If the power generation device 14 includes a single power generation element, the detection unit 28 of the rotation angle detector 1 according to the first embodiment can detect the rotation position of the magnet 20 based on the output of only one power generation element. However, detecting the rotation angle of the magnet 20 based on the output of two or more power generation elements can achieve higher accuracy than detecting the rotation angle of the magnet 20 based on the output of a single power generation element.

[0109] In the above embodiment, the center 24 c of the power generating element 24 is defined by the center point of the magnetic sensitive portion 30 . However, it may be defined by, for example, the center of gravity of the magnetic sensitive portion 30 or the center of gravity of the power generating element 24 .

[0110] In the above embodiment, each power generating element includes a Wiegand wire, but the structure of the power generating element is not limited thereto. For example, each power generating element may be a coil or the like without a Wiegand wire.

[0111] [Effects, etc.]

[0112] Hereinafter, inventions obtained from the disclosure of this specification will be exemplified, and effects obtained from the inventions will be described.

[0113] Invention 1 is a power generation device 14 comprising: a magnet 20 having a circular ring shape centered on a rotation axis A, magnetized in the radial direction of the ring shape, and rotatably arranged about the rotation axis A; and a power generation element 24 (and a power generation element 26) for generating power by changes in the magnetic field associated with the rotation of the magnet 20. If r is the distance from the rotation axis A to the center of the power generation element 24, and R1 and R2 are the inner and outer radii of the magnet 20, respectively, then a positional deviation rate ε representing the relative position of the center of the power generation element 24 with respect to the magnet 20 is defined by the following equation:

[0114] [Formula 4]

[0115]

[0116] Regarding the position deviation rate ε, -50≤ε≤0 holds.

[0117] By using a magnet 20 that is annular and magnetized radially about the rotation axis A, the magnetic flux density distribution within the power generating element 24 can be made uniform. Furthermore, by arranging the power generating element 24 so that its positional deviation ratio ε is between -50% and 0%, variations in the uniformity of the magnetic flux density within the power generating element 24 due to assembly errors in the position of the power generating element 24 along the rotation axis can be suppressed. Consequently, individual variations in the amount of power generated by the power generating element 24 and the rotational angle at which power is generated can be reduced.

[0118] Invention 2 In the power generation device 14 of Invention 1, regarding the position deviation rate ε, -30≤ε≤-10 holds.

[0119] In this way, by configuring the generating element 24 so that the position deviation rate ε of the generating element 24 becomes greater than -30% and less than -10%, the change in the uniformity of the magnetic flux density in the generating element 24 can be further suppressed with respect to the assembly error in the position in the direction of the rotation axis of the generating element 24.

[0120] Invention 3 In the power generating device 14 of Invention 1 or 2, the output of the power generating element 24 changes according to the change in the direction of the magnetic field in the power generating element 24 accompanying the rotation of the magnet 20.

[0121] Thus, the power generating element 24 can detect a change in the relative position (rotation angle) with respect to the magnet 20 based on a change in the magnetic field.

[0122] Invention 4: In the power generating device 14 according to any one of Inventions 1 to 3, the power generating element 24 includes a magnetic member that generates a large Barkhausen effect in response to changes in an external magnetic field.

[0123] Thus, the power generating element 24 can have both a power generation function and a magnetic detection function.

[0124] Invention 5: In the power generating device 14 according to any one of Inventions 1 to 4, the distance from the power generating element 24 to the magnet 20 is larger than the radius of the inner diameter of the magnet 20.

[0125] This can reduce individual differences in the magnetic flux density of the power-generating element 24 due to manufacturing errors and assembly errors in the direction of the rotation axis of the power-generating element 24. Furthermore, it can reduce individual differences in the magnetic flux density of the power-generating element 24 due to assembly errors in the distance r of the power-generating element 24.

[0126] Invention 6 is a rotation angle detector 1 a including the power generating device 14 according to any one of Inventions 1 to 5 and an address information acquiring unit 19 driven by the electromotive force of the power generating element 24 to acquire address information corresponding to the rotation angle of the magnet 20 .

[0127] This makes it possible to detect the rotation angle with higher accuracy compared to the case where the rotation angle of the magnet 20 is detected only by the power generating element 24 .

[0128] Invention 7 is a rotation angle detector 1 including the power generating device 14 according to any one of Inventions 1 to 5 and a detection unit 28 for detecting the rotation angle of the magnet 20 based on the output of the power generating element 24 .

[0129] Thus, the rotation angle of the magnet 20 can be detected with a simplified structure.

[0130] Invention 8 is a method for manufacturing a power generation device 14. The power generation device 14 comprises: a magnet 20, which is a ring-shaped magnet 20 centered on the rotation axis A, magnetized along the radial direction of the ring shape, and arranged to be rotatable around the rotation axis A; and a power generation element 24 (and a power generation element 26) that generates electricity by the change of the magnetic field accompanying the rotation of the magnet 20. The method for manufacturing the power generation device 14 includes: a determination step, which determines the position of the center of the power generation element 24 based on the radius of the inner diameter and the radius of the outer diameter of the magnet 20; and a configuration step, which configures the power generation element 24 and the magnet 20 based on the position determined by the determination step. If the distance from the rotation axis A to the center of the power generation element 24 is set to r, and the radius of the inner diameter and the radius of the outer diameter are set to R1 and R2 respectively, the position deviation rate ε representing the relative position of the center of the power generation element 24 with respect to the magnet 20 is defined by the following formula,

[0131] [Formula 5]

[0132]

[0133] In the determination step, the position of the center of the power generating element 24 is determined so that −50≦ε≦0 holds true with respect to the positional deviation rate ε.

[0134] This has the same effects as those of the first invention.

[0135] Industrial applicability

[0136] The power generation device, the rotation angle detector, and the method for manufacturing the power generation device according to the present disclosure can be used in a rotation angle detector or the like that detects the rotation of a rotating shaft of a motor that rotationally drives a load.

[0137] Explanation of symbols

[0138] 1.1a Rotation angle detector

[0139] 2 motors

[0140] 4 Main body

[0141] 6 rotors

[0142] 8 stator

[0143] 10 Rotation axis

[0144] 12 Housing

[0145] 14 Power Generation Device

[0146] 16 Rotating Plate

[0147] 17 Reflection Pattern

[0148] 18 substrate

[0149] 19 Address Information Acquisition Department

[0150] 20, 120, 220 magnets

[0151] 20c, 24c center

[0152] 21, 121 Part 1

[0153] 22, 122 Part 2

[0154] 24, 26 Power generation elements

[0155] 28 Testing Department

[0156] 30, 34 Magnetic sensing part

[0157] 32, 36 coils

[0158] 223, 224 Magnetic body

[0159] A Axis of rotation.

Claims

1. A power generation device comprising: The magnet is an annular magnet centered on the rotation axis, is magnetized in the radial direction of the annular shape, and is arranged to be rotatable around the rotation axis; and The power generation element generates electricity by the change of the magnetic field accompanying the rotation of the magnet. If the distance from the rotation axis to the center of the power generation element is set to r, and the inner radius and outer radius of the magnet are set to R1 and R2 respectively, the position deviation rate ε representing the relative position of the center of the power generation element with respect to the magnet is defined by the following formula: [Mathematical formula 1] Regarding the position deviation rate ε, -50≤ε≤0 holds true.

2. The power generation device according to claim 1, wherein: Regarding the position deviation rate ε, -30≤ε≤-10 holds true.

3. The power generation device according to claim 1 or 2, wherein: The output of the power generating element changes according to a change in the direction of the magnetic field in the power generating element accompanying the rotation of the magnet.

4. The power generation device according to claim 1 or 2, wherein: The power generating element includes a magnetic member that generates a large Barkhausen effect according to a change in an external magnetic field.

5. The power generation device according to claim 1 or 2, wherein: A distance from the power generating element to the magnet is greater than a radius of an inner diameter of the magnet.

6. A rotation angle detector comprising: The power generation device according to claim 1 or 2; and The address information acquisition unit is driven by the electromotive force of the power generation element and acquires address information corresponding to the rotation angle of the magnet.

7. A rotation angle detector comprising: The power generation device according to claim 1 or 2; and The detection unit detects the rotation angle of the magnet based on the output of the power generation element.

8. A method for manufacturing a power generation device, The power generation device comprises: The magnet is an annular magnet centered on the rotation axis, is magnetized in the radial direction of the annular shape, and is arranged to be rotatable around the rotation axis; and The power generation element generates electricity by the change of the magnetic field accompanying the rotation of the magnet. The manufacturing method of the power generation device comprises: a determining step of determining a position of a center of the power generating element based on an inner radius and an outer radius of the magnet; and an arranging step of arranging the power generating element and the magnet based on the position determined in the determining step, If the distance from the rotation axis to the center of the power generation element is set to r, and the radius of the inner diameter and the radius of the outer diameter are set to R1 and R2 respectively, the position deviation rate ε representing the relative position of the center of the power generation element with respect to the magnet is defined by the following formula: [Mathematical formula 2] In the determining step, the position of the center of the power generating element is determined so that -50≤ε≤0 holds true with respect to the positional deviation rate ε.

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