Detection device

Abstract

To provide a detection device which can detect displacement in a direction orthogonal to an axial direction of a bearing.SOLUTION: The detection device comprises a planar receiving coil, an excitation coil to which an AC excitation voltage is supplied, and a target rotor 80. The target rotor 80 has a configuration in which recesses concave in an axial direction and protrusions protruding toward the recesses in the axial direction are alternately provided in a circumferential direction. The receiving coil includes: an outer coil in which voltage is induced when the excitation voltage is supplied to the excitation coil; and an inner coil in which voltage having the same phase as that of the induced voltage in the outer coil is induced when the excitation voltage is supplied to the excitation coil. In a plan view of each coil, one end part of the outer coil in a radial direction and one end part of the inner coil in the radial direction protrude from ends of the protrusions and the recesses in the radial direction. The outer and inner coils output AC voltage signals having amplitudes corresponding to vertical displacement of the target rotor 80.SELECTED DRAWING: Figure 1

Description

Technical Field

[0006] ,

[0001] The present disclosure relates to a detection device.

Background Art

[0002] Conventionally, a bearing device that rotatably supports a hub fixed to a wheel with respect to a vehicle body is known. The bearing device includes an outer ring fixed to the vehicle body, an inner ring fixed to the hub, and rolling elements between the outer ring and the inner ring. Here, in order to stabilize the running of the vehicle, it is desirable that vehicle running control be performed based on the force acting on the wheel.

[0003] As a configuration for detecting the force acting on a wheel, Patent Document 1 describes an axial strain sensor, a radial strain sensor, and a control unit. The axial strain sensor detects the axial displacement of the outer ring, and the radial strain sensor detects the radial displacement of the outer ring. Since there is a correlation between the displacement and the force acting on the wheel, the displacement can be converted into a force. Therefore, the control unit calculates the axial force of the wheel based on the displacement detected by the axial strain sensor, and calculates the vertical force acting on the wheel based on the displacement detected by the radial strain sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Not limited to vehicles equipped with wheels, in machines equipped with rotating bodies, a new sensor capable of detecting displacement orthogonal to the axial direction of a bearing is desired.

[0006] The main object of the present invention is to provide a detection device capable of detecting displacement in a direction orthogonal to the axial direction of a bearing. [Means for solving the problem]

[0007] This disclosure relates to a detection device applied to a machine having a rotating body, A bearing that rotatably supports the rotating body with respect to the base portion of the machine, A detection target portion extending in the circumferential direction of the bearing and forming an annular shape centered on the bearing, A planar receiving coil is fixed to the base portion and positioned opposite the detection target portion in the axial direction of the bearing, and extends radially in the bearing. It comprises an excitation coil to which an AC excitation voltage is supplied, The detection target unit is provided to rotate in conjunction with the rotation of the rotating body. The receiving coil is An outer coil, which induces a voltage when the excitation voltage is supplied to the excitation coil, When the excitation voltage is supplied to the excitation coil, the inner coil induces a voltage that is in phase with the induced voltage of the outer coil, Includes, The outer coil is positioned at a location that is shifted radially outward from the inner coil. In a plan view of the outer coil and the inner coil, one radial end of the outer coil and one radial end of the inner coil protrude from the radial end of the detection target portion. The outer coil and the inner coil output an AC voltage signal having an amplitude corresponding to the displacement of the detection target in a direction perpendicular to the axial direction when the excitation voltage is supplied to the excitation coil.

[0008] In this disclosure, the detection target portion extends in the circumferential direction and forms an annular shape centered on a bearing. The outer coil and inner coil, positioned opposite the detection target portion in the axial direction, output an AC voltage signal when an excitation voltage is supplied to the excitation coil.

[0009] In a plan view of the outer coil and the inner coil, one end portion in the radial direction of the outer coil and one end portion in the radial direction of the inner coil protrude from the radial end of the detection target portion. As a result, the AC voltage signal output from the outer coil and the inner coil becomes a signal having an amplitude corresponding to the displacement of the detection target portion in a direction orthogonal to the axial direction. Therefore, based on the output voltage signals of the outer and inner coils, the displacement in the direction orthogonal to the axial direction can be detected.

Brief Description of the Drawings

[0010] [Figure 1] Vertical cross-sectional view of a wheel according to the first embodiment. [Figure 2] Plan view of the target rotor. [Figure 3] Perspective view of the target rotor. [Figure 4] Enlarged view of the vicinity of the detection unit in the target rotor. [Figure 5] Plan view of the detection unit. [Figure 6] Diagram showing the electrical configuration of the detection unit. [Figure 7] Diagram showing a state in which the inner wheel is inclined with respect to the outer wheel when a lateral force acts on the tire. [Figure 8] Diagram showing the vertical displacement of the inner wheel when a vertical load acts on the tire. [Figure 9] Plan view of the outer coil. [Figure 10] Plan view of the inner coil. [Figure 11] Plan view of the intermediate coil. [Figure 12] Diagram showing the positional relationship between each coil and the target rotor in the reference state. [Figure 13] Diagram for explaining the detection principle of displacement and rotation angle. [Figure 14] Diagram for explaining the detection principle of displacement and rotation angle. [Figure 15] Simplified plan view of the receiving coil. [Figure 16] Diagram showing the output voltage signal of the receiving coil and the transition of the envelope of this signal. [Figure 17] A diagram showing the change of the output voltage signal of the coil from the reference state when a lateral force acts. [Figure 18] A diagram showing the change of the output voltage signal of the coil from the reference state when a vertical load acts. [Figure 19] A diagram showing the relationship between the radial displacement of the target rotor and the output voltage signal of the coil. [Figure 20] A flowchart showing the procedure of angle and force calculation processing in the receiving circuit. [Figure 21] A diagram showing the positional relationship between each coil and the convex portion of the target rotor according to the second embodiment. [Figure 22] A diagram showing the positional relationship between each coil and the convex portion of the target rotor according to the third embodiment. [Figure 23] A plan view of the target rotor. [Figure 24] A diagram showing the electrical configuration of the detection unit. [Figure 25] A flowchart showing the procedure of angle and force calculation processing in the receiving circuit. [Figure 26] A diagram showing the positional relationship between each coil and the convex portion of the target rotor according to the fourth embodiment. [Figure 27] A flowchart showing the procedure of angle and force calculation processing in the receiving circuit. [Figure 28] A longitudinal sectional view of a wheel according to the fifth embodiment. [Figure 29] A flowchart showing the procedure of force correction processing in the receiving circuit. [Figure 30] A diagram showing each detection unit and the target rotor according to the sixth embodiment. [Figure 31] A sectional view taken along line 31 - 31 of FIG. 30. [Figure 32] A sectional view taken along line 32 - 32 of FIG. 30. [Figure 33] A diagram showing the electrical configuration of each detection unit. [Figure 34] A flowchart showing the procedure of angle and force calculation processing in the receiving circuit. [Figure 35] A plan view of the target rotor according to other embodiments. [Modes for carrying out the invention]

[0011] Multiple embodiments will be described with reference to the drawings. In multiple embodiments, functionally and / or structurally corresponding and / or related parts may be given the same reference numeral, or reference numerals that differ by hundreds or more digits. For corresponding and / or related parts, refer to the descriptions of other embodiments.

[0012] <First Embodiment> Hereinafter, a first embodiment of the detection device relating to this disclosure will be described with reference to the drawings. The vehicle device of this embodiment is configured to calculate the force acting on a wheel (drive wheel) equipped with an in-wheel motor. The vehicle is, for example, a four-wheeled passenger vehicle having two front wheels and two rear wheels. However, the vehicle is not limited to this, and may be a two-wheeled vehicle or other vehicle other than a four-wheeled vehicle. Furthermore, the use of the vehicle is not limited to passenger use.

[0013] As shown in Figure 1, the vehicle's wheels are rotating bodies comprising a wheel 10 and an in-wheel motor 20. The wheel 10 comprises a cylindrical rim portion 11 and a disc portion 12 on a circular disc located at the outer end of the rim portion 11 in the vehicle width direction. A tire 13 is attached to the outer circumference of the rim portion 11.

[0014] The in-wheel motor 20 is housed in the inner space of the wheel 10, which is surrounded by the rim portion 11 and the disc portion 12, and provides rotational power to the wheel 10. The in-wheel motor 20 is an outer rotor type motor comprising a rotor 30 and a stator 40 arranged radially inward of the rotor 30.

[0015] The rotor 30 comprises a cylindrical magnet holder 31 and a magnet unit 32 provided on the inner circumferential surface of the magnet holder 31. The magnet holder 31 faces the inner circumferential surface of the rim portion 11 from the outer end to the inner end in the axial direction (vehicle width direction) of the in-wheel motor 20. The magnet unit 32 is cylindrical and concentric with the rotational axis of the rotor 30, and has a plurality of magnets fixed to the inner circumferential surface of the magnet holder 31. In other words, the in-wheel motor 20 of this embodiment is a surface magnet type synchronous motor (SPMSM). In the magnet unit 32, the magnets are arranged so that their polarity alternates along the circumferential direction of the rotor 30. As a result, a plurality of magnetic poles are formed in the circumferential direction of the magnet unit 32. The magnets are, for example, sintered neodymium magnets. Incidentally, the in-wheel motor 20 may also be an embedded magnet type synchronous motor (IPMSM).

[0016] The rotor 30 is provided at the outer end in the vehicle width direction of the magnet holding portion 31 and includes a disc-shaped flat plate portion 33 that connects the magnet holding portion 31 and the disc portion 12. The disc portion 12 is fixed to the flat plate portion 33 by bolts. As a result, the rotor 30 and the wheel 10 rotate together.

[0017] The stator 40 comprises a cylindrical stator winding 41 positioned radially opposite to the magnet unit 32, and a cylindrical stator base portion 42 provided radially inside the stator winding 41. The stator winding 41 comprises a coil side portion provided radially opposite to the magnet unit 32, and coil end portions provided at both axial ends of the coil side portion.

[0018] The stator base 42 is fixed to the vehicle body, for example, via a knuckle, and holds the stator windings 41, etc. The stator base 42 includes a cylindrical portion 43 fixed to the vehicle body. The portion of the cylindrical portion 43 adjacent to the stator windings 41 in the radial direction is the stator core 43a.

[0019] The stator base 42 is provided with a fixing portion 44 that extends radially inward from one axial end of the cylindrical portion 43. The rotor 30 is rotatably supported relative to the stator base 42 by the fixing portion 44 and the bearing 50. The radially outer end of the fixing portion 44 is an annular projection 45 that protrudes toward the flat plate portion 33. The portion of the projection 45 facing the flat plate portion 33 is a flat surface.

[0020] The bearing 50 is a rolling bearing (e.g., a radial ball bearing) and comprises an outer ring 51 corresponding to a first bearing member, an inner ring 52 corresponding to a second bearing member, and a plurality of rolling elements 53 (e.g., balls) arranged between the outer ring 51 and the inner ring 52. The outer ring 51 is fixed to the fixing part 44 by bolts. The inner ring 52 comprises a cylindrical portion 52a facing the outer ring 51 in the radial direction, and a flange portion 52b extending radially outward from one axial end of the cylindrical portion 52a. The flange portion 52b is fixed to the flat plate portion 33 and the disk portion 12 by bolts. Figure 1 shows the inner ring 52 and the outer ring 51 in a coaxial state.

[0021] The vehicle is equipped with an inverter electrically connected to the stator winding 41 and a DC power supply electrically connected to the inverter. The DC power supply is provided on the vehicle body and is a rechargeable battery such as a lithium-ion battery. The switching control of the upper and lower arm switches that make up the inverter is performed by a control device. As a result, the rotor 30 rotates and the wheels rotate. The inverter and control device may be provided on the vehicle body or may be built into the in-wheel motor 20. The DC power supply may also be a fuel cell, for example.

[0022] A disc-shaped target rotor 80 and a detection unit 90 are provided in the inner space of the wheel 10. The target rotor 80 and the detection unit 90 are used to calculate the rotation angle of the rotor 30 of the in-wheel motor 20 (specifically, the electrical angle or mechanical angle), the rotational speed of the wheel, the lateral force Fy acting between the ground surface GL and the wheel (tire 13), and the force acting between the ground surface GL and the wheel perpendicular to the ground surface GL (hereinafter referred to as the vertical load Fz). The direction in which the lateral force acts and the direction in which the vertical load acts are orthogonal. For example, the calculated rotation angle (electrical angle) is used in the control device for switching control of the inverter, and the wheel rotational speed, lateral force, and vertical load are used in the control device for vehicle driving control.

[0023] As shown in Figures 1 to 3, the target rotor 80 is made of a metal material (for example, iron or aluminum). A through hole 80a is formed in the center of the target rotor 80. The cylindrical portion 52a of the bearing 50 is fitted into the through hole 80a. The target rotor 80 is fixed to the flange portion 52b of the inner ring 52 by bolts, spaced apart from the flat plate portion 33 of the rotor 30 and in surface contact with the flange portion 52b of the inner ring 52. This makes the target rotor 80 and the inner ring 52 coaxial. The target rotor 80, rotor 30, and wheel 10 rotate as a single unit.

[0024] The radially outer end of the target rotor 80 is alternately provided in the circumferential direction with convex portions 82 that protrude from the flat surface 81 of the target rotor 80 in the axial direction of the inner ring 52, and concave portions 83 that protrude from the flat surface 81 in the axial direction and are recessed in the axial direction of the inner ring 52 relative to the convex portions 82. The convex portions 82 and concave portions 83 face the protruding portions 45 of the stator base portion 42. The convex portions 82 and concave portions 83 constitute an annular "detection target portion". In the example shown in Figure 2, 12 sets of convex portions 82 and concave portions 83 are provided.

[0025] In Figure 2, LCi indicates the central axis of the inner ring 52. In this embodiment, the angle α1 between the axis passing through the central axis LCi and one circumferential end of the protrusion 82 and the axis passing through the other circumferential end of the central axis LCi and the protrusion 82 is equal to the angle α2 between the axis passing through the central axis LCi and one circumferential end of the recess 83 and the axis passing through the other circumferential end of the central axis LCi and the recess 83. Therefore, the circumferential length L1 of the protrusion 82 and the circumferential length L2 of the recess 83 are equal.

[0026] The detection unit 90 is a so-called eddy current type inductive sensor. As shown in Figures 2, 4 to 6, the detection unit 90 comprises a substrate 91, a coil section 92 provided on the substrate 91, and a circuit section 93. Figure 2 is a diagram showing the target rotor 80 as viewed from the inside in the vehicle width direction. In Figure 2, the substrate 91 and other components are omitted from the illustration. Figure 4 is an enlarged view of the area around the coil section 92 in Figure 2. Figure 5 is a diagram showing the substrate 91 as viewed from the inside in the vehicle width direction. The substrate 91 is fixed to the flat surface of the protrusion 45. As a result, the substrate 91 extends in a direction perpendicular to the axial direction of the outer ring 51. In this embodiment, the substrate 91 is fixed to the flat surface of the upper end of the annular protrusion 45.

[0027] The coil section 92 comprises an excitation coil 100 and a receiving coil. In this embodiment, the receiving coil consists of an outer coil 110, an inner coil 120, and an intermediate coil 130. Each of the coils 100, 110, 120, and 130 is a planar coil. The substrate 91 is a multilayer substrate. Each of the coils 100, 110, 120, and 130 is composed of wiring patterns and vias formed on each layer of the substrate 91. Because each of the coils 100, 110, 120, and 130 is a planar coil, it is easy to arrange each of the coils 100, 110, 120, and 130 even if it is not possible to secure a wide axial space in the inner space of the wheel 10.

[0028] The circuit section 93 is composed of an integrated circuit. As shown in Figures 5 and 6, the circuit section 93 includes an excitation circuit 94 that supplies a high-frequency excitation voltage to the excitation coil 100, and a receiving circuit 95. When an excitation voltage is supplied to the excitation coil 100, an excitation current flows through the excitation coil 100, and a voltage with the same or equivalent frequency as the excitation voltage is induced in each of the coils 110, 120, and 130. The receiving circuit 95 detects the voltage signals across each of the coils 110, 120, and 130. Specifically, the receiving circuit 95 detects the potential difference across the outer coil 110 as an outer voltage signal Vso, the potential difference across the inner coil 120 as an inner voltage signal Vsi, and the potential difference across the intermediate coil 130 as an intermediate voltage signal Vc.

[0029] As shown in Figure 1, the circuit section 93 of the detection unit 90 is electrically connected to the processing section 70. More specifically, a through hole 46 is formed in the protruding portion 45, and the processing section 70 and the circuit section 93 are electrically connected via wiring inserted through the through hole 46. The processing section 70 may be provided on the vehicle body or built into the in-wheel motor 20.

[0030] The circuit unit 93 and the processing unit 70 are primarily composed of a microcontroller, for example. The functions provided by the microcontroller in the circuit unit 93 and the processing unit 70 can be provided by software recorded in a physical memory device and a computer that executes it, by software only, by hardware only, or by a combination thereof. For example, when the microcontroller is provided by an electronic circuit which is hardware, it can be provided by a digital circuit containing a large number of logic circuits, or by an analog circuit. For example, the microcontroller executes a program stored in a non-transitory tangible storage medium which serves as its own memory. When the program is executed, the method corresponding to the program is executed. The memory is, for example, non-volatile memory. The program stored in the memory can be updated via a network such as the Internet, such as OTA (Over The Air).

[0031] As shown in Figure 1, when a lateral force Fy acts on the wheel, the inclination θ of the central axis LCo of the inner ring 52 relative to the central axis LCo of the outer ring 51 increases, as shown in Figure 7. In this case, the axial distance between each coil 110, 120, 130 and the target rotor 80 changes, and the amplitude of the output voltage signals of each coil 110, 120, 130 changes. The detection unit 90 calculates the axial displacement ΔY of the target rotor 80 based on this amplitude change, and calculates the lateral force Fy based on the calculated axial displacement ΔY.

[0032] On the other hand, when a vertical load Fz acts on the wheel, as shown in Figure 8, the central axis LCo of the inner ring 52 is displaced in a direction perpendicular to the central axis LCo of the outer ring 51. As a result, the target rotor 80 fixed to the flange portion 52b is also displaced. In this case, the detection unit 90 is configured so that the amplitude of the output voltage signals of the outer coil 110 and the inner coil 120 changes. This configuration will be described in detail later. Based on this amplitude change, the detection unit 90 calculates the displacement of the target rotor 80 in the axial direction and in the direction perpendicular to the vehicle length direction (hereinafter referred to as vertical displacement ΔZ), and calculates the vertical load Fz based on the calculated vertical displacement ΔZ.

[0033] As shown in Figure 4, the outer coil 110, inner coil 120, and intermediate coil 130 are located in the region surrounded by the excitation coil 100 in a plan view of the substrate 91. The excitation coil 100 is a planar coil with multiple turns and has an arc shape extending in the circumferential direction of the outer ring 51.

[0034] The outer coil 110, inner coil 120, and intermediate coil 130 are composed of a first part that generates a voltage of first polarity between the ends of the coil when an excitation voltage is supplied to the excitation coil 100, and a second part that generates a voltage of second polarity which is the opposite polarity to the first polarity.

[0035] More specifically, as shown in Figure 9, the outer coil 110 is composed of a first part 110P and a second part 110M. In a plan view of the substrate 91, one side of the outer coil 110 is the first part 110P and the other side is the second part 110M with respect to the central axis Lt in the circumferential direction. The central axis Lt is an axis that extends in the radial direction and passes through the central axis LCi. The first part 110P and the second part 110M are aligned in the circumferential direction. The first part 110P has a shape that is symmetrical to the shape of the second part 110M with respect to the central axis Lt.

[0036] As shown in Figure 10, the inner coil 120 is composed of a first part 120P and a second part 120M. In this embodiment, the inner coil 120 has a similar shape to the outer coil 110. Therefore, a detailed description of the inner coil 120 is omitted.

[0037] As shown in Figure 11, the intermediate coil 130 is composed of a first portion 130P and a second portion 130M. In a plan view of the substrate 91, the first portion 130P and second portion 130M on one side and the first portion 130P and second portion 130M on the other side are symmetrical with respect to the circumferential central axis Lt of the intermediate coil 130. In this embodiment, the radial length of the intermediate coil 130 is greater than the radial lengths of the outer coil 110 and the inner coil 120. Also, the circumferential lengths of each coil 110, 120, and 130 are equivalent.

[0038] In each coil 110, 120, and 130, the circumferential length from the central axis Lt to the circumferential end is the same as the total circumferential length (L1 + L2) of the convex portion 82 and the concave portion 83. Also, as shown in Figure 4, in a plan view of the substrate 91, the positions of both circumferential ends of each coil 110, 120, and 130 are the same.

[0039] As shown in Figure 4, in a plan view of the substrate 91, the radial outer end of the outer coil 110 in the reference state protrudes radially outward from the radial outer ends 84 of the convex portion 82 and concave portion 83. The reference state can be set arbitrarily. The reference state is, for example, the state of a stationary vehicle, specifically, for example, the state in which a vehicle is stationary on a horizontal road surface.

[0040] In a plan view of the substrate 91, the radial inner end of the outer coil 110 and the radial outer end of the inner coil 120 in the reference state are located between the radial outer end 84 and the radial inner end 85 of the convex portion 82 and the concave portion 83.

[0041] In a plan view of the substrate 91, the radial inner end of the inner coil 120 in the reference state protrudes radially inward from the radial inner ends 85 of the convex portion 82 and the concave portion 83.

[0042] In this embodiment, the radially inner portion of the outer coil 110 and the radially outer portion of the intermediate coil 130 overlap in a plan view of the substrate 91. Furthermore, the radially inner portion of the intermediate coil 130 and the radially outer portion of the inner coil 120 overlap in a plan view of the substrate 91. This reduces the radial length of the substrate 91.

[0043] Next, we will explain the principle by which the detection unit 90 can detect displacement and rotation angle.

[0044] First, we will explain the outline of this principle using Figures 13 and 14. As shown in Figure 13, when a high-frequency excitation voltage vr(t) is supplied to the excitation coil, a high-frequency current flows through the excitation coil. This current generates a magnetic flux φ(t), which links with the receiving coil. A voltage ve(t) proportional to the time rate of change of the linked magnetic flux is induced at both ends of the receiving coil.

[0045] Figure 14 shows a state in which the protrusion 82 of the target rotor 80 faces a portion of the receiving coil in the radial direction. Eddy currents flow in the portion of the protrusion 82 facing the receiving coil due to the flux linkage caused by the energization of the excitation coil. These eddy currents generate a magnetic flux in a direction that weakens the magnetic flux that generates the induced voltage in the receiving coil, and the amplitude of the induced voltage in the receiving coil becomes smaller. In other words, the amplitude of the potential difference at both ends of the receiving coil is proportional to the area of ​​the receiving coil that does not face the protrusion 82 in the radial direction.

[0046] Based on the explanations in Figures 13 and 14, the detection principles of displacement and rotation angle will be explained using Figures 15 and 16. Figures 15 and 16 show the receiving coil 140 and the protrusion 82 arranged in a straight line in the circumferential direction. Figure 16 shows the relative positional relationship between the receiving coil 140 and the protrusion 82, and the change in the output voltage signal Va of the receiving coil 140.

[0047] In Figures 15 and 16, the direction in which current flows from the second end 142 to the first end 141 of the receiving coil 140 (I+) is referred to as the positive direction, and the direction in which current flows from the first end 141 to the second end 142 (I-) is referred to as the negative direction. Also, in Figures 15 and 16, the magnetic flux from the excitation coil 100 passes from the front to the back of the page.

[0048] At time t1 in Figure 16, the central half of the first part 140P and the central half of the second part 140M of the receiving coil 140 face the convex portion 82 in the axial direction. A voltage is induced in the first part 140P that tends to conduct current in the positive direction, and a voltage is induced in the second part 140M that tends to conduct current in the negative direction. As a result, the induced voltage generated in the first part 140P and the induced voltage generated in the second part 140M cancel each other out, and the amplitude of the output voltage signal Va becomes 0.

[0049] At time t2, the second part 140M of the first part 140P and second part 140M faces the convex portion 82. In this case, a voltage is induced in the first part 140P that attempts to induce a current in the positive direction, and the induced voltage in the second part 140M becomes 0. As a result, the amplitude of the output voltage signal Va becomes the maximum value on the first polarity (positive polarity) side. This maximum value increases as the convex portion 82 of the target rotor 80 approaches the receiving coil 140.

[0050] At time t3, the end half of the first section 140P and the end half of the second section 140M face the convex portion 82. A voltage is induced in the first section 140P that tends to conduct current in the positive direction, and a voltage is induced in the second section 140M that tends to conduct current in the negative direction. As a result, the induced voltage generated in the first section 140P and the induced voltage generated in the second section 140M cancel each other out, and the amplitude of the output voltage signal Va becomes 0.

[0051] At time t4, the first part 140P faces the convex portion 82. In this case, a voltage is induced in the second part 140M that tends to cause current to flow in the negative direction, and the induced voltage of the first part 140P becomes 0. As a result, the amplitude of the output voltage signal Va becomes the maximum value on the second polarity (negative polarity) side, which is the opposite polarity to the first polarity. This maximum value increases as the convex portion 82 approaches the receiving coil 140.

[0052] In this embodiment, convex portions 82 and concave portions 83 are alternately formed on the radially outer end of the target rotor 80. Therefore, during the rotation of the rotor 30, the amplitude of the output voltage signal Va of the receiving coil 140 changes periodically, and as shown by the dashed line in Figure 16, the envelope ENV of the output voltage signal Va becomes sinusoidal. In this embodiment, since the circumferential spacing of the magnetic pole positions of the magnet unit 32 and the circumferential lengths of the convex portions 82 and concave portions 83 are set in relation to each other, the amplitude of the output voltage signal Va or envelope ENV can be linked to the electrical angle θe.

[0053] In this embodiment, when an excitation voltage is supplied to the excitation coil 100, the phase difference between the external voltage signal Vso output from the outer coil 110 and the internal voltage signal Vsi output from the inner coil 120 is 0 degrees. Also, when an excitation voltage is supplied to the excitation coil 100, the phase difference between the external voltage signal Vso and the internal voltage signal Vsi with respect to the intermediate voltage signal Vc output from the intermediate coil 130 is 90 degrees. Therefore, the phase difference between the envelope of the external voltage signal Vso (or internal voltage signal Vsi) and the envelope of the intermediate voltage signal Vc is also 90 degrees.

[0054] In this embodiment, the amplitude of the outer voltage signal Vso is equal to the amplitude of the inner voltage signal Vsi. Furthermore, the amplitude of the outer voltage signal Vso is smaller than the amplitude of the intermediate voltage signal Vc. This is because, as shown in Figure 12, in a plan view of the substrate 91, the area surrounded by the intermediate coil 130 is larger than the area surrounded by the outer coil 110.

[0055] This section explains the case where the lateral force acting on the wheel changes.

[0056] When the direction of the lateral force is directed outward in the vehicle width direction, the inner ring 52 tilts relative to the outer ring 51 such that the upper end of the target rotor 80 approaches the stator base portion 42 and the lower end approaches the wheel 10. In this case, the axial displacement ΔY of the target rotor 80 is defined as positive. As the axial displacement ΔY increases in the positive direction, the amplitude of the intermediate voltage signal Vc output from the intermediate coil 130 increases, as shown by the solid line in Figure 17(a). In Figure 17(a), the intermediate voltage signal Vc shown by the dashed line is the intermediate voltage signal Vc in the reference state. Figure 17 is a diagram showing the excitation coil 100, the intermediate coil 130, and the protrusion 82 with the circumferential direction being linear. In the figure, the hatched portion is the part of the intermediate coil 130 that faces the protrusion 82 in the radial direction.

[0057] When the direction of the lateral force is directed inward in the vehicle width direction, the inner ring 52 tilts relative to the outer ring 51 such that the lower end of the target rotor 80 approaches the stator base 42 and the upper end approaches the wheel 10. In this case, the axial displacement ΔY is considered negative. As the axial displacement ΔY increases in the negative direction, the amplitude of the intermediate voltage signal Vc decreases, as shown by the solid line in Figure 17(b). Note that in Figure 17(b), the intermediate voltage signal Vc shown by the dashed line is the intermediate voltage signal Vc in the reference state.

[0058] Next, we will explain the case where the vertical load acting on the wheel changes.

[0059] Figure 18(a) shows the relative positional relationship of the outer coil 110, the inner coil 120, and the protrusion 82 in the reference state. Figure 18 is a diagram showing the excitation coil 100, the outer coil 110, the inner coil 120, and the protrusion 82 arranged in a straight line in the circumferential direction. In the figure, the hatched parts are the parts of each coil 110 and 120 that face the protrusion 82 in the radial direction. In Figure 18, the dashed lines represent the voltage signals Vso and Vsi in the reference state.

[0060] When the upward vertical load increases, the upper end of the target rotor 80 is displaced upward. In this case, the vertical displacement ΔZ of the target rotor 80 is taken as positive. As the vertical displacement ΔZ increases in the positive direction, the amplitude of the external voltage signal Vso output from the external coil 110 increases, and the amplitude of the internal voltage signal Vsi output from the internal coil 120 decreases, as shown by the solid line in Figure 18(b). The reason the amplitude of the external voltage signal Vso increases is that as the target rotor 80 is displaced upward, the area of ​​the part of the external coil 110 facing the convex portion 82 increases. The reason the amplitude of the internal voltage signal Vsi decreases is that as the target rotor 80 is displaced upward, the area of ​​the part of the internal coil 120 facing the convex portion 82 decreases.

[0061] On the other hand, when the downward vertical load increases, the upper end of the target rotor 80 is displaced downward. In this case, the vertical displacement ΔZ is considered negative. As the vertical displacement ΔZ increases in the negative direction, the amplitude of the outer voltage signal Vso decreases and the amplitude of the inner voltage signal Vsi increases, as shown by the solid line in Figure 18(c). The reason the amplitude of the outer voltage signal Vso decreases is that as the target rotor 80 is displaced downward, the area of ​​the part of the outer coil 110 facing the protrusion 82 decreases. The reason the amplitude of the inner voltage signal Vsi increases is that as the target rotor 80 is displaced downward, the area of ​​the part of the inner coil 120 facing the protrusion 82 increases.

[0062] From the above, the vertical displacement ΔZ (i.e., the vertical load Fz) can be calculated based on the external voltage signal Vso or the internal voltage signal Vsi. In this embodiment, the receiving circuit 95 calculates the vertical load Fz based on the differential voltage Vssub, which is the value obtained by subtracting the external voltage signal Vso from the internal voltage signal Vsi. This calculation method is a method to improve the accuracy of calculating the vertical load Fz. In other words, as shown in Figure 19, in the radial (vertical) displacement range that the target rotor 80 can take, the range of change of the differential voltage Vssub is larger than the range of change of the external voltage signal Vso and the internal voltage signal Vsi. This is because the direction of change of the amplitude of the external voltage signal Vso with respect to the vertical displacement of the target rotor 80 is opposite to the direction of change of the amplitude of the internal voltage signal Vsi with respect to the vertical displacement of the target rotor 80. In this embodiment, it is assumed that the amplitude of the differential voltage Vssub and the amplitude of the intermediate voltage signal Vc are the same.

[0063] The procedure for calculation processing in the receiving circuit 95 will be explained using Figures 20 and 6. This process is executed repeatedly, for example, at a predetermined control cycle.

[0064] In step S10, the calculation circuit 96 of the receiving circuit 95 calculates the combined voltage Vsadd by adding the outer voltage signal Vso to the inner voltage signal Vsi. In this embodiment, the process in step S10 corresponds to the "combined voltage calculation unit".

[0065] In step S11, the calculation circuit 96 calculates the differential voltage Vssub by subtracting the outer voltage signal Vso from the inner voltage signal Vsi. In this embodiment, the process in step S11 corresponds to the "differential voltage calculation unit".

[0066] In step S12, the lateral force angle calculation unit 97 of the receiving circuit 95 calculates the electrical angle θe based on the calculated combined voltage Vsadd and the intermediate voltage signal Vc. An example of the method for calculating the electrical angle θe is described below.

[0067] The lateral force angle calculation unit 97 calculates the envelope of the combined voltage Vsadd and the envelope of the intermediate voltage signal Vc. The lateral force angle calculation unit 97 calculates the electrical angle θe by performing an arctangent calculation on the ratio of the envelope of the combined voltage Vsadd and the envelope of the intermediate voltage signal Vc. In this embodiment, the processing in step S12 corresponds to the "angle calculation unit".

[0068] The lateral force angle calculation unit 97 may also calculate the wheel rotation speed based on the time derivative of the calculated electrical angle.

[0069] In step S13, the lateral force angle calculation unit 97 calculates the lateral force Fy based on the intermediate voltage signal Vc. An example of the method for calculating the lateral force Fy is described below.

[0070] The lateral force angle calculation unit 97 calculates the envelope of the intermediate voltage signal Vc. The lateral force angle calculation unit 97 calculates the amount of deviation of the amplitude of the calculated intermediate voltage signal Vc envelope from the amplitude of the intermediate voltage signal Vc envelope in the reference state as an axial displacement signal. The axial displacement signal is updated each time the maximum amplitude on the positive polarity side and the maximum amplitude on the negative polarity side of the intermediate voltage signal Vc appear. In other words, when the rotational speed of the rotor 30 is constant, the axial displacement signal is updated every 180 degrees of electrical angle. The lateral force angle calculation unit 97 calculates the lateral force Fy based on map information or mathematical formula information to which the axial displacement signal and the lateral force Fy are related.

[0071] In step S14, the vertical load calculation unit 98 of the receiving circuit 95 calculates the vertical load Fz based on the calculated differential voltage Vssub. An example of the method for calculating the vertical load Fz is described below.

[0072] The vertical load calculation unit 98 calculates the envelope of the differential voltage Vssub. The vertical load calculation unit 98 calculates the amount of deviation of the calculated amplitude of the differential voltage Vssub envelope from the amplitude of the differential voltage Vssub envelope in the reference state as a vertical displacement signal. The vertical displacement signal is updated each time the maximum amplitude on the positive polarity side and the maximum amplitude on the negative polarity side of the differential voltage Vssub appear. In other words, when the rotational speed of the rotor 30 is constant, the vertical displacement signal is updated every 180 degrees of electrical angle. The vertical load calculation unit 98 calculates the vertical load Fz based on map information or mathematical formula information relating the vertical displacement signal and the vertical load Fz. In this embodiment, the processing in step S14 corresponds to the "force calculation unit".

[0073] The map information or formula information used in steps S13 and S14 may be stored in, for example, a memory unit (e.g., non-volatile memory) provided by the receiving circuit 95. Furthermore, in a configuration where the output voltage signals of each coil 110, 120, and 130 are input to the processing unit 70, the processing shown in Figure 20 may be executed in the processing unit 70 instead of the receiving circuit 95.

[0074] In step S14, the amplitude-increased differential voltage Vssub is used to calculate the vertical load Fz, thereby improving the accuracy of the vertical load Fz calculation.

[0075] According to the embodiment described above, the following further effects can be achieved.

[0076] A single detection unit 90 can calculate the wheel's rotational speed and electrical angle, in addition to the load acting on the wheel. This allows for a reduction in the number of on-board sensors.

[0077] A detection unit 90 is provided in the stator base 42 at a position radially away from the bearing 50 and axially opposite to the radial end of the target rotor 80. The portion of the target rotor 80 that faces the detection unit 90 in the axial direction is the portion radially outward from the bearing 50. Therefore, when a lateral force acts on the wheel, the axial displacement of the portion of the target rotor 80 that faces the detection unit 90 in the axial direction can be increased. As a result, the detection accuracy of the axial displacement ΔY can be improved, and consequently, the calculation accuracy of the lateral force Fy of the wheel, which constitutes the unsprung weight of the vehicle, can be improved.

[0078] Because the in-wheel motor 20 is configured as an outer rotor type, the radial end of the target rotor 80 can be positioned at a large radial distance from the bearing 50. This improves the accuracy of the calculation of the lateral force Fy.

[0079] Each of the coils 100, 110, 120, and 130 is positioned axially closer to the wheel 10 than the coil end portion that constitutes the stator winding 41. This suppresses the influence of noise and other noises associated with energizing the stator winding 41 on the excitation voltage of the excitation coil 100 and the induced voltages of each of the coils 110, 120, and 130. As a result, the accuracy of calculating the electrical angle θe, lateral force Fy, and vertical load Fz can be improved.

[0080] <Modified form of the first embodiment> In a plan view of the substrate 91, the outer coil 110 and the intermediate coil 130 may be spaced apart radially, and the intermediate coil 130 and the inner coil 120 may also be spaced apart radially.

[0081] The shapes of the outer coil 110 and the inner coil 120 are not limited to those shown in Figures 9 and 10, but may also be, for example, the shape shown in Figure 11. Similarly, the shape of the intermediate coil 130 is not limited to those shown in Figure 11, but may also be, for example, the shape shown in Figure 9. In this case, the shapes of the three coils 110, 120, and 130 may be the same. In this case, the phases of the outer voltage signal Vso, the inner voltage signal Vsi, and the intermediate voltage signal Vc will be the same.

[0082] <Second Embodiment> The second embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, as shown in Figure 21, in a plan view of the substrate 91, the radially inner portion of the outer coil 110 and the radially outer portion of the inner coil 120 overlap. Figure 21 is a diagram showing the excitation coil 100, the outer coil 110, the inner coil 120, and the protrusion 82 with the circumferential direction being linear.

[0083] According to this embodiment, the radial length of the substrate 91 can be reduced.

[0084] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the detection unit 90 includes a first coil 150 and a second coil 160 as receiving coils, instead of the intermediate coil 130, as shown in Figure 22. The target rotor 80 has the configuration shown in Figure 23. Figure 22 is a diagram showing the excitation coil 100, outer coil 110, inner coil 120, first coil 150, and second coil 160, etc., with their circumferential directions arranged in a straight line.

[0085] First, let me explain the target rotor 80.

[0086] At the radially outer end of the target rotor 80, there are alternating outer protrusions 82o that project from the flat surface 81 in the axial direction of the inner ring 52, and recesses 83 that project from the flat surface 81 in the axial direction and are recessed in the axial direction of the inner ring 52 relative to the outer protrusions 82o, arranged in the circumferential direction. The outer protrusions 82o and recesses 83 constitute an annular "outer detection target portion".

[0087] In the target rotor 80, an inner protrusion 82i is provided in the radially inner portion relative to each outer protrusion 82o, via an intermediate recess 86. The outer protrusion 82o and the inner protrusion 82i are aligned radially. The axial length of the inner protrusion 82i relative to the recess 83 is the same as the axial length of the outer protrusion 82o relative to the recess 83. The intermediate recess 86 is a portion that is recessed in the axial direction relative to the outer protrusion 82o and the inner protrusion 82i, and also forms an annular shape. The inner protrusion 82i and the recess 83 constitute an annular "inner detection target portion".

[0088] Next, the first coil 150 and the second coil 160 will be explained using Figure 22.

[0089] The first coil 150 and the second coil 160 are planar coils and are composed of wiring patterns and vias formed on each layer of the substrate 91. The shapes of the first coil 150 and the second coil 160 are the same as those of the intermediate coil 130 in the first embodiment. In this embodiment, the radial lengths of the first coil 150 and the second coil 160 are smaller than the radial lengths of the outer coil 110 and the inner coil 120.

[0090] The first coil 150 is located on the substrate 91, radially outward from the second coil 160. In a plan view of the substrate 91, the radial outer end and inner end of the first coil 150 are located between the radial outer end 84 and the inner end 87 of the outer protrusion 82o, and closer to the radial inner end 87. In a plan view of the substrate 91, the radial outer end and inner end of the second coil 160 are located between the radial outer end 88 and the inner end 85 of the inner protrusion 82i, and closer to the radial outer end 88.

[0091] In a plan view of the substrate 91, the radial outer end of the outer coil 110 is located between the radial outer end 84 and the inner end 87 of the outer protrusion 82o. In a plan view of the substrate 91, the radial inner end of the outer coil 110 protrudes radially inward from the radial inner end 87 of the outer protrusion 82o.

[0092] In a plan view of the substrate 91, the radial outer end of the inner coil 120 protrudes radially outward from the radial outer end 88 of the inner protrusion 82i. In a plan view of the substrate 91, the radial inner end of the inner coil 120 is located between the radial outer end 88 and the inner end 85 of the inner protrusion 82i. In a plan view of the substrate 91, the circumferential end positions of each coil 110, 120, 150, and 160 are the same.

[0093] When an excitation voltage is supplied to the excitation coil 100, an excitation current flows through the excitation coil 100, inducing voltages with the same or equivalent frequency as the excitation voltage in the first coil 150 and the second coil 160. As shown in Figure 24, the receiving circuit 95 detects the potential difference across the first coil 150 as a first voltage signal Vco and the potential difference across the second coil 160 as a second voltage signal Vci.

[0094] When an excitation voltage is supplied to the excitation coil 100, the phase difference between the first voltage signal Vco output from the first coil 150 and the second voltage signal Vci output from the second coil 160 is 0 degrees. Also, when an excitation voltage is supplied to the excitation coil 100, the phase difference between the outer voltage signal Vso and the inner voltage signal Vsi with respect to the first voltage signal Vco and the second voltage signal Vci is 90 degrees.

[0095] In this embodiment, the amplitude of the first voltage signal Vco is basically equal to the amplitude of the second voltage signal Vci. Also, the amplitudes of the first and second voltage signals Vco and Vci are smaller than the amplitude of the outer voltage signal Vso. This is because, in a plan view of the substrate 91, the area surrounded by the first coil 150 (or the second coil 160) is smaller than the area surrounded by the outer coil 110.

[0096] In this embodiment, the combined voltage Vsadd described in the first embodiment will be referred to as the first combined voltage. The receiving circuit 95 calculates the lateral force Fy based on the second combined voltage Vcadd, which is the value obtained by adding the second voltage signal Vci to the first voltage signal Vco. This is to improve the accuracy of the calculation of the lateral force Fy.

[0097] In a front view of the substrate 91, the first coil 150 is located near the radial inner end 87 of the outer protrusion 82o, and the second coil 160 is located near the radial outer end 88 of the inner protrusion 82i. In this case, when the target rotor 80 is displaced vertically, the first voltage signal Vco output from the first coil 150 and the second voltage signal Vci output from the second coil 160 may fluctuate temporarily. In this case, the accuracy of calculating the lateral force Fy based on the first voltage signal Vco or the second voltage signal Vci may decrease.

[0098] Here, the polarity of the transient fluctuation of the first voltage signal Vco is opposite to the polarity of the transient fluctuation of the second voltage signal Vci. Therefore, the second combined voltage Vcadd, which is the value obtained by adding the second voltage signal Vci to the first voltage signal Vco, becomes an AC signal in which transient fluctuations are suppressed (specifically, for example, canceled).

[0099] The procedure for calculation processing in the receiving circuit 95 will be explained using Figures 24 and 25. This process is executed repeatedly, for example, at a predetermined control cycle.

[0100] In step S20, the calculation circuit 96 calculates the first combined voltage Vsadd by adding the outer voltage signal Vso to the inner voltage signal Vsi. In this embodiment, the process in step S20 corresponds to the "first combined voltage calculation unit".

[0101] In step S21, the calculation circuit 96 calculates the differential voltage Vssub by subtracting the outer voltage signal Vso from the inner voltage signal Vsi. In this embodiment, the process in step S21 corresponds to the "differential voltage calculation unit".

[0102] In step S22, the combining circuit 99 of the receiving circuit 95 calculates the second combined voltage Vcadd by adding the second voltage signal Vci to the first voltage signal Vco. In this embodiment, the processing in step S22 corresponds to the "second combined voltage calculation unit".

[0103] In step S23, the lateral force angle calculation unit 97 calculates the electrical angle θe based on the calculated first combined voltage Vsadd and second combined voltage Vcadd. An example of the method for calculating the electrical angle θe is described below.

[0104] The lateral force angle calculation unit 97 calculates the envelope of the first combined voltage Vsadd and the envelope of the second combined voltage Vcadd. The lateral force angle calculation unit 97 calculates the electrical angle θe by performing an arctangent calculation on the ratio of the envelope of the first combined voltage Vsadd and the envelope of the second combined voltage Vcadd. The calculation accuracy of the electrical angle θe can be improved by the process in step S23. In this embodiment, the process in step S23 corresponds to the "angle calculation unit".

[0105] In step S24, the lateral force angle calculation unit 97 calculates the lateral force Fy based on the second combined voltage Vcadd. An example of the method for calculating the lateral force Fy is described below.

[0106] The lateral force angle calculation unit 97 calculates the envelope of the second combined voltage Vcadd. The lateral force angle calculation unit 97 calculates the amount of deviation of the amplitude of the calculated envelope of the second combined voltage Vcadd from the amplitude of the envelope of the second combined voltage Vcadd in the reference state as an axial displacement signal. The axial displacement signal is updated each time the maximum amplitude on the positive polarity side and the maximum amplitude on the negative polarity side of the second combined voltage Vcadd appear. The lateral force angle calculation unit 97 calculates the lateral force Fy based on map information or mathematical formula information to which the axial displacement signal and the lateral force Fy are related.

[0107] In step S25, the vertical load calculation unit 98 calculates the vertical load Fz based on the calculated differential voltage Vssub, similar to the process in step S14 of Figure 20.

[0108] According to the embodiment described above, even if the first coil 150 and the second coil 160 are arranged as shown in Figure 22, the accuracy of calculating the lateral force Fy can be improved.

[0109] <Modified form of the third embodiment> Similar to the second embodiment, in a plan view of the substrate 91, the radially inner portion of the outer coil 110 and the radially outer portion of the inner coil 120 may overlap.

[0110] <Fourth Embodiment> The fourth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. The detection unit 90 of this embodiment includes a plurality of outer coils and the same number of inner coils as the outer coils, as a receiving coil formed on the substrate 91, as shown in Figure 26. In this embodiment, two outer coils are provided. The detection unit 90 includes a first outer coil 111 and a second outer coil 112, and a first inner coil 121 and a second inner coil 122. Figure 26 is a diagram showing the excitation coil 100, each outer coil 111, 112, each inner coil 121, 122 and the protrusion 82, with the circumferential direction being linear.

[0111] The shapes of the first outer coil 111 and the second outer coil 112 are the same as the shape of the outer coil 110 in the first embodiment, and the shapes of the first inner coil 121 and the second inner coil 122 are the same as the shape of the inner coil 120 in the first embodiment. The positional relationship between the first outer coil 111, the first inner coil 121 and the intermediate coil 130 is the same as the positional relationship between the outer coil 110, the inner coil 120 and the intermediate coil 130 in the first embodiment.

[0112] The second outer coil 112 is located at the same position radially as the first outer coil 111. The second outer coil 112 is located at a position offset by a predetermined length K in the circumferential direction relative to the first outer coil 111. In this embodiment, the predetermined length K is 1 / 4 the length of the circumferential length of the first outer coil 111. The predetermined length K corresponds to an electrical angle of 90 degrees.

[0113] The second inner coil 122 is located at the same position as the first inner coil 121 in the radial direction. The second inner coil 122 is located at a position offset by the predetermined length K in the circumferential direction from the first inner coil 121. In other words, the second inner coil 122 is aligned with the second outer coil 112 in the radial direction.

[0114] When an excitation voltage is supplied to the excitation coil 100, an excitation current flows through the excitation coil 100, inducing voltages with the same or equivalent frequency as the excitation voltage in the first outer coil 111, the second outer coil 112, the first inner coil 121, and the second inner coil 122. The receiving circuit 95 detects the potential difference across the first outer coil 111 as the first outer voltage signal Vso1, and the potential difference across the second outer coil 112 as the second outer voltage signal Vso2. The receiving circuit 95 also detects the potential difference across the first inner coil 121 as the first inner voltage signal Vsi1, and the potential difference across the second inner coil 122 as the second inner voltage signal Vsi2.

[0115] When an excitation voltage is supplied to the excitation coil 100, the phase difference between the first external voltage signal Vso1 output from the first external coil 111 and the first internal voltage signal Vsi1 output from the first internal coil 121 is 0 degrees. Also, when an excitation voltage is supplied to the excitation coil 100, the phase difference between the second external voltage signal Vso2 output from the second external coil 112 and the second internal voltage signal Vsi2 output from the second internal coil 122 is 0 degrees. The phase difference between the second external voltage signal Vso2 and the second internal voltage signal Vsi2 with respect to the first external voltage signal Vso1 and the first internal voltage signal Vsi1 is 90 degrees.

[0116] As shown in Figure 26, the outer and inner coils are arranged in a circumferential direction to increase the frequency of updating the vertical load Fz. When half of the first and half of the second portion of the receiving coil face the convex portion 82, the envelope of the differential voltage Vssub becomes 0 (see time t3 in Figure 16). In this case, the vertical displacement signal based on the differential voltage envelope is updated every 180 degrees of electrical angle.

[0117] On the other hand, according to the arrangement shown in Figure 26, there is an envelope of the differential voltage based on the first outer voltage signal Vso1 and the first inner voltage signal Vsi1, and an envelope of the differential voltage based on the second outer voltage signal Vso2 and the second inner voltage signal Vsi2, so the vertical displacement signal is updated every 90 degrees of electrical angle. As a result, the update frequency of the vertical load Fz based on the vertical displacement signal can be increased.

[0118] The procedure for calculation processing in the receiving circuit 95 will be explained using Figure 27. This process is repeatedly executed by the receiving circuit 95 at a predetermined control cycle, for example.

[0119] In step S30, the lateral force Fy is calculated based on the intermediate voltage signal Vc, similar to step S13 in Figure 20.

[0120] In step S31, the electrical angle θe is calculated based on the first external voltage signal Vso1, the first internal voltage signal Vsi1, and the intermediate voltage signal Vc. An example of how to calculate the electrical angle θe is described below.

[0121] The combined voltage is calculated by adding the first inner voltage signal Vsi1 to the first outer voltage signal Vso1, and the envelope of the calculated combined voltage and the envelope of the intermediate voltage signal Vc are calculated. The electrical angle θe is calculated by performing an arctangent calculation on the ratio of the envelope of the combined voltage and the envelope of the intermediate voltage signal.

[0122] In step S32, based on the calculated electrical angle θe, it is selected whether to use the first outer voltage signal Vso1 and the first inner voltage signal Vsi1, or the second outer voltage signal Vso2 and the second inner voltage signal Vsi2, to calculate the vertical load Fz. The selection is based on the electrical angle θe because the waveforms of the envelopes of the first differential voltage Vssub1 and the second differential voltage Vssub2 depend on the electrical angle θe. Based on the electrical angle θe, the outer and inner voltage signals corresponding to the envelopes of the first differential voltage Vssub1 and the second differential voltage Vssub2 with larger absolute values ​​are selected. The following explanation will use the case where the first outer voltage signal Vso1 and the first inner voltage signal Vsi1 are selected as an example.

[0123] In step S33, the first differential voltage Vssub1 is calculated by subtracting the first external voltage signal Vso1 from the first internal voltage signal Vsi1. In step S34, the vertical load Fz is calculated based on the calculated first differential voltage Vssub1, similar to step S14 in Figure 20.

[0124] If the first external voltage signal Vso1 and the first internal voltage signal Vsi1 are selected in step S32, then in step S33, the second differential voltage Vssub2 is calculated by subtracting the second external voltage signal Vso2 from the second internal voltage signal Vsi2. In step S34, the vertical load Fz is calculated based on the calculated second differential voltage Vssub2, similar to step S14 in Figure 20.

[0125] According to the embodiment described above, the frequency of updating the vertical load Fz can be increased.

[0126] <Modified form of the fourth embodiment> The predetermined length K, which is the circumferential displacement of adjacent outer coils in the circumferential direction, is not limited to 1 / 4 of the circumferential length of the outer coil, but may be, for example, 1 / 6 or 1 / 12. In the case of 1 / 6, the predetermined length K corresponds to an electrical angle of 60 degrees, and in the case of 1 / 12, the predetermined length K corresponds to an electrical angle of 30 degrees. For example, if the length is 1 / 6, three outer and inner coils may be arranged in a row in the circumferential direction. Also, for example, if the length is 1 / 12, five outer and inner coils may be arranged in a row in the circumferential direction.

[0127] <Fifth Embodiment> The fifth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, as shown in Figure 28, the bearing 50 is positioned such that its center in the vehicle width direction is inward in the vehicle width direction than the center of the wheel 10 that constitutes the wheel. This increases the vertical displacement of the target rotor 80 with respect to the vertical load acting on the tire 13.

[0128] Here, the center position of the wheel 10 in the vehicle width direction is, for example, the center position Lh of the rim portion 11 constituting the wheel 10 in the vehicle width direction.

[0129] The bearing 50 is a double-row bearing in which two rows of rolling elements 53 are arranged in the axial direction. Here, the center position of the bearing 50 in the vehicle width direction is, for example, the center position Lb of the two rows of rolling elements 53 in the vehicle width direction.

[0130] The offset amount Loff between the center position of the wheel 10 in the vehicle width direction and the center position of the bearing 50 in the vehicle width direction affects the accuracy of the calculation of the vertical load Fz. Therefore, the receiving circuit 95 performs a correction process on the calculated vertical load Fz based on the offset amount Loff. The correction process performed by the vertical load calculation unit 98 of the receiving circuit 95 will be explained below with reference to Figure 29.

[0131] In step S40, the offset amount Loff is obtained. The offset amount Loff can be obtained, for example, from an inspection device at a vehicle repair shop or via a communication network. If an event occurs that changes the offset amount Loff, such as the replacement of the tire 13, the updated offset amount Loff is obtained in step S40.

[0132] In step S41, the vertical load Fz calculated in step S14 of Figure 20 is corrected based on the offset amount Loff obtained in step S40. The larger the offset amount Loff, the greater the vertical displacement of the target rotor 80 when a vertical load is applied, and the larger the amplitude of the differential voltage Vssub. For this reason, for example, the vertical load Fz may be corrected so that the vertical load Fz increases as the offset amount Loff increases.

[0133] According to the embodiment described above, the accuracy of calculating the vertical load Fz can be improved.

[0134] <Sixth Embodiment> The sixth embodiment will now be described, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the configuration of the target rotor 170 has been changed, as shown in Figures 30 to 32. Accordingly, a first detection unit 90A and a second detection unit 90B are provided as detection units. Figure 31 is a cross-sectional view taken along line 31-31 of Figure 30, and Figure 32 is a cross-sectional view taken along line 32-32 of Figure 30.

[0135] The target rotor 170 is annular in shape and is arranged coaxially with the inner ring 52. The target rotor 170 is fixed to the rotor 30 (for example, the magnet holder portion 31 or the flat plate portion 33) or to the flange portion 52b of the bearing 50. As a result, the target rotor 170, the rotor 30, and the wheel 10 rotate as a single unit.

[0136] The target rotor 170 comprises a first rotor portion 180, a second rotor portion 280, and an annular connecting portion 171 connecting the first rotor portion 180 and the second rotor portion 280. As shown in Figures 30 and 31, the first rotor portion 180 has alternating first convex portions 182 projecting axially from an annular first flat surface 181 and first recesses 183 projecting axially from the first flat surface 181 and recessed axially relative to the first convex portions 182 in the circumferential direction. The first convex portions 182 and the first recesses 183 constitute an annular "first detection target portion". Similar to the first embodiment, the circumferential length of the first convex portion 182 is equal to the circumferential length of the first recess 183.

[0137] As shown in Figures 30 and 32, the second rotor portion 280 is provided with alternating second protrusions 282 projecting axially from the annular second flat surface 281 and second recesses 283 projecting axially from the second flat surface 281 and recessed axially relative to the second protrusions 282 in the circumferential direction. The second protrusions 282 and the second recesses 283 constitute an annular "second detection target portion". Similar to the first embodiment, the circumferential length of the second protrusions 282 is equal to the circumferential length of the second recesses 283.

[0138] The first rotor section 180 and the second rotor section 280 have the same shape. Therefore, the circumferential length of the first convex section 182 is equal to the circumferential length of the second convex section 282, and the circumferential length of the first concave section 183 is equal to the circumferential length of the second concave section 283.

[0139] The first protrusion 182 of the first rotor portion 180 faces the second protrusion 282 of the second rotor portion 280 in the axial direction. The first recess 183 of the first rotor portion 180 faces the second recess 283 of the second rotor portion 280 in the axial direction.

[0140] Next, the first detection unit 90A and the second detection unit 90B will be described.

[0141] As shown in Figures 31 and 33, the first detection unit 90A includes a first excitation coil 100A, a first outer coil 110A, a first inner coil 120A, a first intermediate coil 130A, and a first excitation circuit 94A. The configuration of the first detection unit 90A is the same as that of the detection unit 90 in the first embodiment. Therefore, a detailed description of the first detection unit 90A is omitted.

[0142] As shown in Figures 32 and 33, the second detection unit 90B includes a second excitation coil 100B, a second outer coil 110B, a second inner coil 120B, a second intermediate coil 130B, and a second excitation circuit 94B. The configuration of the second detection unit 90B is the same as that of the first detection unit 90A. Therefore, a detailed description of the second detection unit 90B is omitted.

[0143] The first detection unit 90A and the second detection unit 90B are fixed to the protruding portion 45 of the stator base portion 42. Specifically, the stator base portion 42 includes an extension portion 45a extending outward in the vehicle width direction from the protruding portion 45, and a mounting portion 45b extending upward from the extension portion 45a. The mounting portion 45b has a first mounting surface and a second mounting surface which is the back surface of the first mounting surface. The first detection unit 90A is mounted on the first mounting surface such that the first excitation coil 100A, the first outer coil 110A, the first inner coil 120A, and the first intermediate coil 130A face the first convex portion 182 and the first concave portion 183 in the axial direction. The second detection unit 90B is mounted on the second mounting surface such that the second excitation coil 100B, the second outer coil 110B, the second inner coil 120B, and the second intermediate coil 130B face the second convex portion 282 and the second concave portion 283 in the axial direction. The first detection unit 90A is positioned on the back surface of the second detection unit 90B, with the mounting portion 45b in between.

[0144] As shown in Figure 33, in this embodiment, a receiving circuit 95 is provided separately from each detection unit 90A, 90B. The receiving circuit 95 detects the potential difference across both ends of the first outer coil 110A as a first outer voltage signal VsoA, the potential difference across both ends of the first inner coil 120A as a first inner voltage signal VsiA, and the potential difference across both ends of the first intermediate coil 130A as a first intermediate voltage signal VcA. The receiving circuit 95 detects the potential difference across both ends of the second outer coil 110B as a second outer voltage signal VsoB, the potential difference across both ends of the second inner coil 120B as a second inner voltage signal VsiB, and the potential difference across both ends of the second intermediate coil 130B as a second intermediate voltage signal VcB.

[0145] The phase difference between the first external voltage signal VsoA and the second external voltage signal VsoB is 0 degrees, and the phase difference between the first internal voltage signal VsiA and the second internal voltage signal VsiB is 0 degrees. Also, the phase difference between the first intermediate voltage signal VcA and the second intermediate voltage signal VcB is 0 degrees.

[0146] When the direction of the lateral force is directed outward in the vehicle width direction, the upper end of the first rotor section 180 moves closer to the mounting section 45b, and the upper end of the second rotor section 280 moves away from the mounting section 45b. In this case, the amplitude of the first intermediate voltage signal VcA increases, and the amplitude of the second intermediate voltage signal VcB decreases.

[0147] On the other hand, when the direction of the lateral force is directed inward in the vehicle width direction, the upper end of the first rotor portion 180 moves away from the mounting portion 45b, and the upper end of the second rotor portion 280 moves closer to the mounting portion 45b. In this case, the amplitude of the first intermediate voltage signal VcA decreases, and the amplitude of the second intermediate voltage signal VcB increases.

[0148] Thus, the direction of change in the amplitude of the first intermediate voltage signal VcA with respect to the axial displacement of the target rotor 170 is opposite to the direction of change in the amplitude of the second intermediate voltage signal VcB with respect to the axial displacement of the target rotor 170. For this reason, by using the differential voltage Vcsub obtained by subtracting the second intermediate voltage signal VcB from the first intermediate voltage signal VcA, the voltage amplitude can be increased, and the accuracy of calculating the lateral force Fy can be improved.

[0149] The procedure for calculation processing in the receiving circuit 95 will be explained using Figure 34. This process is executed repeatedly, for example, at a predetermined control cycle.

[0150] In step S40, the first combined voltage Vsadd is calculated by adding the first outer voltage signal VsoA to the first inner voltage signal VsiA.

[0151] In step S41, the first differential voltage Vssub is calculated by subtracting the first outer voltage signal VsoA from the first inner voltage signal VsiA.

[0152] In step S42, the second combined voltage Vcadd is calculated by adding the second intermediate voltage signal VcB to the first intermediate voltage signal VcA.

[0153] In step S43, the second differential voltage Vcsub is calculated by subtracting the second intermediate voltage signal VcB from the first intermediate voltage signal VcA. In this embodiment, the process in step S43 corresponds to the "differential voltage calculation unit".

[0154] In step S44, the electrical angle θe is calculated based on the calculated first combined voltage Vsadd and the calculated second combined voltage Vcadd. An example of how to calculate the electrical angle θe is described below.

[0155] The envelopes of the first combined voltage Vsadd and the second combined voltage Vcadd are calculated. The electrical angle θe is calculated by performing an arctangent calculation on the ratio of the envelopes of the first combined voltage Vsadd and the second combined voltage Vcadd.

[0156] In step S45, the lateral force Fy is calculated based on the second differential voltage Vcsub. An example of how to calculate the lateral force Fy is described below.

[0157] The envelope of the second differential voltage Vcsub is calculated. The amount of deviation of the calculated amplitude of the envelope of the second differential voltage Vcsub from the amplitude of the envelope of the second differential voltage Vcsub in the reference state is calculated as an axial displacement signal. The axial displacement signal is updated each time the maximum amplitude on the positive side and the maximum amplitude on the negative side of the second differential voltage Vcsub appear. The lateral force Fy is calculated based on map information or mathematical formula information relating the axial displacement signal and the lateral force Fy. In this embodiment, the processing in step S45 corresponds to the "force calculation unit".

[0158] In step S46, the vertical load Fz is calculated based on the calculated first differential voltage Vssub.

[0159] According to the embodiment described above, since the second differential voltage Vcsub, whose amplitude has been increased, is used to calculate the lateral force Fy, the accuracy of the calculation of the lateral force Fy can be improved.

[0160] <Other Embodiments> Furthermore, each of the above embodiments may be implemented with the following modifications.

[0161] As shown in Figure 35, the detection unit 90 may be provided near either the front or rear end of the target rotor 80 in the vehicle's longitudinal direction. In Figure 35, HL indicates the horizontal axis passing through the central axis LSi of the inner ring 52.

[0162] According to the arrangement of the detection unit 90 shown in Figure 35, the receiving circuit 95 can calculate the longitudinal load Fx, which is the force acting between the ground contact surface GL and the wheels in the vehicle's longitudinal direction, instead of the vertical load Fz. The direction in which the lateral force Fy acts and the direction in which the longitudinal load Fx acts are orthogonal. The longitudinal load Fx is used in the control device for controlling the vehicle's movement.

[0163] The following explanation will be given using the case where the detection unit 90 is located near the front end of the vehicle at both ends of the target rotor 80 in the vehicle's longitudinal direction. The longitudinal load Fx is defined as positive when the vehicle is accelerating, and negative when the vehicle is decelerating. When the longitudinal load Fx is positive, the target rotor 80 is displaced toward the direction of vehicle travel. In the first embodiment, this corresponds to a state in which the upward vertical load acting on the wheels increases. On the other hand, when the longitudinal load Fx is negative, the target rotor 80 is displaced toward the opposite direction of vehicle travel. In the first embodiment, this corresponds to a state in which the downward vertical load acting on the wheels increases.

[0164] The target rotor may be fixed to the rotor (e.g., the flat plate portion 33).

[0165] At least a portion of the motor may be located outside the inner space of the wheel 10.

[0166] The in-wheel motor 20 does not necessarily have a target rotor 80. In this case, for example, the portion of the flat plate portion 33 of the in-wheel motor 20 that faces the coil portion 92 in the axial direction may have convex portions 82 and concave portions 83 alternately formed in the circumferential direction. In this case, the flat plate portion 33 corresponds to the "detection target portion".

[0167] • The target rotor 80 may not have a protrusion 82, and a recess 83 may be formed in an annular shape over the entire circumferential direction of the target rotor 80. Even in this case, the lateral force Fy and the vertical load Fz can be calculated.

[0168] The bearing is not limited to one in which the outer ring 51 is fixed to the stator base 42 and the inner ring 52 is fixed to the wheel 10, but may also be one in which the outer ring is fixed to the wheel 10 and the inner ring is fixed to the stator base 42. In this case, the inner ring corresponds to the "first bearing member" and the outer ring corresponds to the "second bearing member".

[0169] The motor is not limited to an outer rotor type; an inner rotor type is also acceptable.

[0170] The detection unit 90 may be provided in a state where at least a portion of it is in contact with the target rotor 80.

[0171] The detection device is not limited to vehicle wheels, but can be applied to any machine equipped with a rotating body, such as aircraft propellers, ship propellers, internal combustion engine rotating members (e.g., crankshafts), or power generation turbines. Furthermore, the rotating body is not limited to those used with its axial direction horizontal, but may also be used with its axial direction in a direction other than horizontal (e.g., vertical).

[0172] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium.

[0173] The following describes the characteristic configurations extracted from each of the embodiments described above. [Configuration 1] In a detection device applied to a machine equipped with a rotating body (10), A bearing (50) rotatably supports the rotating body with respect to the base portion (42) of the machine, The detection target portion (82, 83, 182, 183, 282, 283) extends in the circumferential direction of the bearing and forms an annular shape centered on the bearing, A planar receiving coil (110, 120, 130, 150, 160, 111, 112, 121, 122, 110A, 120A, 130A, 110B, 120B, 130B) is fixed to the base portion and positioned opposite the detection target portion in the axial direction of the bearing, and extends in the radial direction of the bearing, It comprises excitation coils (100, 100A, 100B) to which an AC excitation voltage is supplied, The detection target unit is provided to rotate in conjunction with the rotation of the rotating body. The receiving coil is The outer coils (110, 111, 112, 110A, 110B) from which a voltage is induced when the excitation voltage is supplied to the excitation coil, When the excitation voltage is supplied to the excitation coil, the inner coils (120, 121, 122, 120A, 120B) induce a voltage that is in phase with the induced voltage of the outer coil, Includes, The outer coil is positioned at a location that is shifted radially outward from the inner coil. In a plan view of the outer coil and the inner coil, one radial end of the outer coil and one radial end of the inner coil protrude from the radial end of the detection target portion. The outer coil and the inner coil are a detection device that, when the excitation voltage is supplied to the excitation coil, outputs an AC voltage signal having an amplitude corresponding to the displacement of the part to be detected in a direction perpendicular to the axial direction. [Configuration 2] In a plan view of the outer coil (110-112) and the inner coil (120-122), the radial outer end of the outer coil protrudes from the radial outer end (84) of the detection target portion. In a plan view of the outer coil and the inner coil, the radial inner end of the outer coil and the radial outer end of the inner coil are located between the radial outer end and the radial inner end (85) of the detection target portion. The detection device according to configuration 1, wherein, in a plan view of the outer coil and the inner coil, the radial inner end of the inner coil protrudes from the radial inner end of the part to be detected. [Configuration 3] A differential voltage calculation unit (96) calculates a differential voltage (Vssub), which is the difference between the output voltage signal of the outer coil (110) and the output voltage signal of the inner coil (120). A force calculation unit (98) calculates the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to configuration 2, comprising: [Structure 4] The detection target portion has a configuration in which recesses (83) that are recessed in the axial direction and protrusions (82) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The receiving coil includes an intermediate coil (130) that, when the excitation voltage is supplied to the excitation coil, induces a voltage that is in a different phase from the voltage induced in the outer coil and the inner coil. In a plan view of the outer coil, the inner coil, and the intermediate coil, the radial outer end and inner end of the intermediate coil are located between the radial outer end and inner end of the detection target portion. The intermediate coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the part to be detected in the axial direction. A combined voltage calculation unit (96) calculates a combined voltage (Vsadd), which is the sum of the output voltage signal of the outer coil and the output voltage signal of the inner coil. An angle calculation unit (97) calculates the rotation angle of the rotating body based on the combined voltage calculated by the combined voltage calculation unit and the output voltage signal of the intermediate coil, A detection device comprising any one of configurations 1 to 3. [Composition 5] The outer coils (111, 112) are arranged in a plurality in the circumferential direction, The inner coils (121, 122) are individually provided at positions aligned with the outer coils in the radial direction. The outer coils adjacent to each other in the circumferential direction are arranged such that a portion of them overlaps in a plan view of the outer coils. The detection device according to configuration 2, wherein the inner coils adjacent to each other in the circumferential direction are arranged such that a portion of them overlaps in a plan view of the inner coils. [Composition 6] A differential voltage calculation unit (95) selects one set from among the sets of outer coils and inner coils arranged in the radial direction and calculates a differential voltage which is the difference between the output voltage signal of the outer coil and the output voltage signal of the inner coil that constitute the selected set. A force calculation unit (95) calculates the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to configuration 5, comprising the above. [Composition 7] The detection target unit is, External detection target parts (82o, 83), An inner detection target portion (82i, 83) is provided in the radial direction, which is located inside the outer detection target portion. It has, The outer detection target portion and the inner detection target portion are configured such that recesses (83) that are recessed in the axial direction and protrusions (82o, 82i) that project from the recesses in the axial direction are alternately provided in the circumferential direction. In the detection target portion, an intermediate recess (86) is formed between the outer detection target portion and the inner detection target portion in the radial direction, which is recessed in the axial direction relative to the convex portion and forms an annular shape. The outer detection target portion, the protrusion, and the protrusion of the inner detection target portion are aligned in the radial direction. In a plan view of the outer coil and the inner coil, the radial outer end of the outer coil is located between the radial outer end (84) and the inner end (87) of the outer detection target portion. In a plan view of the outer coil and the inner coil, the radial inner end of the outer coil protrudes from the radial inner end of the outer detection target portion. In a plan view of the outer coil and the inner coil, the radial outer end of the inner coil extends beyond the radial outer end (88) of the inner detection target portion. The detection device according to configuration 1, wherein in a plan view of the outer coil and the inner coil, the radial inner end of the inner coil is located between the radial outer end and the radial inner end (85) of the inner detection target portion. [Structure 8] A differential voltage calculation unit (96) calculates a differential voltage (Vssub), which is the difference between the output voltage signal of the outer coil and the output voltage signal of the inner coil. A force calculation unit (98) calculates the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to configuration 7, comprising: [Composition 9] The receiving coil is When the excitation voltage is supplied to the excitation coil, a first coil (150) is provided which induces a voltage that is in phase with the voltage induced in the outer coil and the inner coil, When the excitation voltage is supplied to the excitation coil, a second coil (160) is induced that has the same phase as the induced voltage of the first coil, Includes, The first coil is provided on the outer side of the second coil in the radial direction, In a plan view of the outer coil, the inner coil, the first coil, and the second coil, the radial outer end and inner end of the first coil are located between the radial outer end and inner end of the outer detection target portion, and closer to the radial inner end of the outer detection target portion. In a plan view of the outer coil, the inner coil, the first coil, and the second coil, the radial outer end and inner end of the second coil are located between the radial outer end and inner end of the inner detection target portion, and closer to the radial outer end of the inner detection target portion. The first coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the outer detection target in the axial direction. The second coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the inner detection target in the axial direction. A first combined voltage calculation unit (96) calculates a first combined voltage (Vsadd), which is the sum of the output voltage signal of the outer coil and the output voltage signal of the inner coil. A second combined voltage calculation unit (99) calculates a second combined voltage (Vcadd), which is the sum of the output voltage signal of the first coil and the output voltage signal of the second coil. An angle calculation unit (97) calculates the rotation angle of the rotating body based on the first combined voltage calculated by the first combined voltage calculation unit and the second combined voltage calculated by the second combined voltage calculation unit, A detection device according to configuration 7 or 8, comprising the above. [Configuration 10] A detection device according to any one of configurations 1 to 9, wherein, in a front view of the outer coil and the inner coil, the radially inner portion of the outer coil and the radially outer portion of the inner coil overlap. [Composition 11] The machine is equipped with a motor (20) which serves as the power source for the rotation of the rotating body. The motor has a rotor (30) that includes a magnet unit (32) that forms a plurality of magnetic poles with alternating polarities in the circumferential direction, The angle calculation unit is a detection device according to configuration 4 or 9 that calculates the rotation angle of the rotor. [Composition 12] The receiving coil is A first portion (110P, 120P, 130P) that generates a voltage of first polarity across the receiving coil when the excitation voltage is supplied to the excitation coil, When the excitation voltage is supplied to the excitation coil, a second portion (110M, 120M, 130M) generates a voltage with a second polarity opposite to the first polarity at both ends of the receiving coil, It has, The receiving coil is In a plan view of the receiving coil, the first portion (110P, 120P) is provided on one side of the circumferential center of the receiving coil, and the second portion (110M, 120M) is provided on the other side, and the first portion and the second portion are arranged in the circumferential direction, or In a plan view of the receiving coil, the first portion (130P) and second portion (130M) on one side and the first portion and second portion on the other side are configured symmetrically with respect to the center of the receiving coil in the circumferential direction. A detection device as described in any one of configurations 1 to 11. [Composition 13] The detection device according to any one of configurations 1 to 12, wherein the machine is a vehicle equipped with wheels as the rotating body. [Composition 14] The detection device according to configuration 13, wherein the bearing is positioned such that the center position (Lb) of the bearing in the vehicle width direction is inward in the vehicle width direction than the center position (Lh) of the wheel constituting the wheel. [Composition 15] A detection device according to configuration 14, which is dependent on any one of configurations 3, 6, or 8, comprising a correction unit that acquires the offset amount (Loff) between the center position of the wheel in the vehicle width direction and the center position of the bearing in the vehicle width direction, and corrects the force calculated by the force calculation unit based on the acquired offset amount. [Composition 16] The detection target unit is, The first detection target unit, A second detection target is provided at a position opposite to the first detection target in the axial direction, It has, The first detection target portion and the second detection target portion are configured such that recesses (183, 283) that are recessed in the axial direction and protrusions (182, 282) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The first detection target unit is arranged such that the recess and protrusion of the first detection target unit face the recess and protrusion of the second detection target unit. The receiving coil is A first intermediate coil (130A) is provided at a position opposite to the first detection target unit, A second intermediate coil (130B) is provided at a position opposite to the second detection target unit, Includes, When the excitation voltage is supplied to the excitation coil, the first intermediate coil and the second intermediate coil are configured such that a voltage in the same phase as the voltage induced in the second intermediate coil is induced in the first intermediate coil. A differential voltage calculation unit (95) calculates a differential voltage (Vcsub), which is the difference between the output voltage signal of the first intermediate coil and the output voltage signal of the second intermediate coil. A force calculation unit (95) calculates the force (Fy) acting on the rotating body in the axial direction based on the differential voltage calculated by the differential voltage calculation unit, A detection device according to configuration 1, comprising the above. [Configuration A: Program claim corresponding to Configuration 3] In the program applied to the detection device described in Configuration 3, On the computer, A process to calculate the differential voltage (Vssub), which is the difference between the output voltage signal of the outer coil (110) and the output voltage signal of the inner coil (120), A process to calculate the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the calculated differential voltage, A program that executes something. [Configuration B: Program claims corresponding to Configuration 4] In the program applied to the detection device described in Configuration 3, The detection target portion has a configuration in which recesses (83) that are recessed in the axial direction and protrusions (82) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The receiving coil includes an intermediate coil (130) that, when the excitation voltage is supplied to the excitation coil, induces a voltage that is in a different phase from the voltage induced in the outer coil and the inner coil. In a plan view of the outer coil, the inner coil, and the intermediate coil, the radial outer end and inner end of the intermediate coil are located between the radial outer end and inner end of the detection target portion. The intermediate coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the part to be detected in the axial direction. On the computer, A process to calculate the combined voltage (Vsadd), which is the sum of the output voltage signal of the outer coil and the output voltage signal of the inner coil, A process to calculate the rotation angle of the rotating body based on the calculated composite voltage and the output voltage signal of the intermediate coil, A program that executes something. [Configuration C: Program claim corresponding to Configuration 6] In the program applied to the detection device described in Configuration 5, On the computer, A process to select one set from among the sets of outer coils and inner coils arranged in the radial direction, and to calculate the differential voltage, which is the difference between the output voltage signal of the outer coil and the output voltage signal of the inner coil that constitute the selected set, A process to calculate the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the calculated differential voltage, A program that executes something. [Configuration D: Program claim corresponding to Configuration 8] In the program applied to the detection device described in Configuration 8, On the computer, A process to calculate the differential voltage (Vssub), which is the difference between the output voltage signal of the outer coil and the output voltage signal of the inner coil, A process to calculate the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the calculated differential voltage, A program that executes something. [Configuration E: Program claim corresponding to Configuration 9] In the program applied to the detection device described in Configuration 8, The receiving coil is When the excitation voltage is supplied to the excitation coil, a first coil (150) is provided which induces a voltage that is in phase with the voltage induced in the outer coil and the inner coil, When the excitation voltage is supplied to the excitation coil, a second coil (160) is induced that has the same phase as the induced voltage of the first coil, Includes, The first coil is provided on the outer side of the second coil in the radial direction, In a plan view of the outer coil, the inner coil, the first coil, and the second coil, the radial outer end and inner end of the first coil are located between the radial outer end and inner end of the outer detection target portion, and closer to the radial inner end of the outer detection target portion. In a plan view of the outer coil, the inner coil, the first coil, and the second coil, the radial outer end and inner end of the second coil are located between the radial outer end and inner end of the inner detection target portion, and closer to the radial outer end of the inner detection target portion. The first coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the outer detection target in the axial direction. The second coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the inner detection target in the axial direction. On the computer, A process to calculate a first combined voltage (Vsadd), which is the sum of the output voltage signal of the outer coil and the output voltage signal of the inner coil, A process for calculating a second combined voltage (Vcadd), which is the sum of the output voltage signal of the first coil and the output voltage signal of the second coil, A process for calculating the rotation angle of the rotating body based on the calculated first combined voltage and the calculated second combined voltage, A program that executes something. [Configuration F: Program claim corresponding to Configuration 15] In the program applied to the detection device described in configuration 14, On the computer, A process to obtain the offset amount (Loff) between the center position of the wheel in the vehicle width direction and the center position of the bearing in the vehicle width direction, A process to correct the force calculated by the force calculation unit based on the acquired offset amount, A program that executes something. [Configuration G: Program claim corresponding to Configuration 16] In the program applied to the detection device described in Configuration 1, The detection target unit is, The first detection target unit, A second detection target is provided at a position opposite to the first detection target in the axial direction, It has, The first detection target portion and the second detection target portion are configured such that recesses (183, 283) that are recessed in the axial direction and protrusions (182, 282) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The first detection target unit is arranged such that the recess and protrusion of the first detection target unit face the recess and protrusion of the second detection target unit. The receiving coil is A first intermediate coil (130A) is provided at a position opposite to the first detection target unit, A second intermediate coil (130B) is provided at a position opposite to the second detection target unit, Includes, When the excitation voltage is supplied to the excitation coil, the first intermediate coil and the second intermediate coil are configured such that a voltage in the same phase as the voltage induced in the second intermediate coil is induced in the first intermediate coil. On the computer, A process for calculating the differential voltage (Vcsub), which is the difference between the output voltage signal of the first intermediate coil and the output voltage signal of the second intermediate coil, A process to calculate the force (Fy) acting on the rotating body in the axial direction based on the calculated differential voltage, A program that executes something. [Configuration H] A machine equipped with a rotating body (10), Detection device and In a program applied to a system that includes the following features, The detection device is A bearing (50) rotatably supports the rotating body with respect to the base portion (42) of the machine, A first detection target portion (182, 183) extends in the circumferential direction of the bearing and forms an annular shape centered on the bearing, The second detection target portion (282, 283) extends in the circumferential direction and forms an annular shape centered on the bearing, A planar receiving coil (130A, 130B) is fixed to the base portion and positioned opposite the detection target portion in the axial direction of the bearing, and extends radially in the bearing. Excitation coils (100, 100A, 100B) to which AC excitation voltage is supplied, Equipped with, The first detection target unit and the second detection target unit are provided to rotate in conjunction with the rotation of the rotating body. The second detection target unit is provided at a position facing the first detection target unit in the axial direction, The first detection target portion and the second detection target portion are configured such that recesses (183, 283) that are recessed in the axial direction and protrusions (182, 282) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The first detection target unit is arranged such that the recess and protrusion of the first detection target unit face the recess and protrusion of the second detection target unit. The receiving coil is A first intermediate coil (130A) is provided at a position opposite to the first detection target unit, A second intermediate coil (130B) is provided at a position opposite to the second detection target unit, Includes, When the excitation voltage is supplied to the excitation coil, the first intermediate coil and the second intermediate coil are configured such that a voltage in the same phase as the voltage induced in the second intermediate coil is induced in the first intermediate coil. On the computer, A process for calculating the differential voltage (Vcsub), which is the difference between the output voltage signal of the first intermediate coil and the output voltage signal of the second intermediate coil, A process to calculate the force (Fy) acting on the rotating body in the axial direction based on the calculated differential voltage, A program that executes something. [Explanation of Symbols]

[0174] 10...Wheel, 50...Bearing, 80...Target rotor, 94...Excitation circuit, 95...Receiver circuit, 100...Excitation coil, 110...Outer coil, 120...Inner coil, 130...Intermediate coil.

Claims

1. In a detection device applied to a machine equipped with a rotating body (10), A bearing (50) rotatably supports the rotating body with respect to the base portion (42) of the machine, The detection target portion (82, 83, 182, 183, 282, 283) extends in the circumferential direction of the bearing and forms an annular shape centered on the bearing, A planar receiving coil (110, 120, 130, 150, 160, 111, 112, 121, 122, 110A, 120A, 130A, 110B, 120B, 130B) is fixed to the base portion and positioned opposite the detection target portion in the axial direction of the bearing, and extends in the radial direction of the bearing, Excitation coils (100, 100A, 100B) to which AC excitation voltage is supplied, Equipped with, The detection target unit is provided to rotate in conjunction with the rotation of the rotating body. The receiving coil is The outer coils (110, 111, 112, 110A, 110B) from which a voltage is induced when the excitation voltage is supplied to the excitation coil, When the excitation voltage is supplied to the excitation coil, the inner coils (120, 121, 122, 120A, 120B) induce a voltage that is in phase with the induced voltage of the outer coil, Includes, The outer coil is positioned at a location that is shifted radially outward from the inner coil. In a plan view of the outer coil and the inner coil, one radial end of the outer coil and one radial end of the inner coil protrude from the radial end of the detection target portion. The outer coil and the inner coil are a detection device that, when the excitation voltage is supplied to the excitation coil, outputs an AC voltage signal having an amplitude corresponding to the displacement of the part to be detected in a direction perpendicular to the axial direction.

2. In a plan view of the outer coils (110-112) and the inner coils (120-122), the radial outer end of the outer coil extends beyond the radial outer end (84) of the detection target portion. In a plan view of the outer coil and the inner coil, the radial inner end of the outer coil and the radial outer end of the inner coil are located between the radial outer end and the radial inner end (85) of the detection target portion. The detection device according to claim 1, wherein, in a plan view of the outer coil and the inner coil, the radial inner end of the inner coil protrudes from the radial inner end of the part to be detected.

3. A differential voltage calculation unit (96) calculates a differential voltage (Vssub), which is the difference between the output voltage signal of the outer coil (110) and the output voltage signal of the inner coil (120). A force calculation unit (98) calculates the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to claim 2, comprising:

4. The detection target portion has a configuration in which recesses (83) that are recessed in the axial direction and protrusions (82) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The receiving coil includes an intermediate coil (130) that, when the excitation voltage is supplied to the excitation coil, induces a voltage that is in a different phase from the voltage induced in the outer coil and the inner coil. In a plan view of the outer coil, the inner coil, and the intermediate coil, the radial outer end and inner end of the intermediate coil are located between the radial outer end and inner end of the detection target portion. The intermediate coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the part to be detected in the axial direction. A combined voltage calculation unit (96) calculates a combined voltage (Vsadd), which is the sum of the output voltage signal of the outer coil and the output voltage signal of the inner coil. An angle calculation unit (97) calculates the rotation angle of the rotating body based on the combined voltage calculated by the combined voltage calculation unit and the output voltage signal of the intermediate coil, A detection device according to any one of claims 1 to 3, comprising:

5. The outer coils (111, 112) are arranged in a plurality in the circumferential direction, The inner coils (121, 122) are individually provided at positions aligned with the outer coils in the radial direction. The outer coils adjacent to each other in the circumferential direction are arranged such that a portion of them overlaps in a plan view of the outer coils. The detection device according to claim 2, wherein the inner coils adjacent to each other in the circumferential direction are arranged such that a portion of them overlaps in a plan view of the inner coils.

6. A differential voltage calculation unit (95) selects one set from among the sets of outer coils and inner coils arranged in the radial direction and calculates a differential voltage which is the difference between the output voltage signal of the outer coil and the output voltage signal of the inner coil that constitute the selected set. A force calculation unit (95) calculates the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to claim 5, comprising:

7. The detection target unit is, External detection target parts (82o, 83) An inner detection target portion (82i, 83) is provided in the radial direction, which is located inside the outer detection target portion. It has, The outer detection target portion and the inner detection target portion are configured such that recesses (83) that are recessed in the axial direction and protrusions (82o, 82i) that project from the recesses in the axial direction are alternately provided in the circumferential direction. In the detection target portion, an intermediate recess (86) is formed between the outer detection target portion and the inner detection target portion in the radial direction, which is recessed in the axial direction relative to the convex portion and forms an annular shape. The protrusions of the outer detection target portion and the protrusions of the inner detection target portion are aligned in the radial direction. In a plan view of the outer coil and the inner coil, the radial outer end of the outer coil is located between the radial outer end (84) and the inner end (87) of the outer detection target portion. In a plan view of the outer coil and the inner coil, the radial inner end of the outer coil protrudes from the radial inner end of the outer detection target portion. In a plan view of the outer coil and the inner coil, the radial outer end of the inner coil extends beyond the radial outer end (88) of the inner detection target portion. The detection device according to claim 1, wherein, in a plan view of the outer coil and the inner coil, the radial inner end of the inner coil is located between the radial outer end and the radial inner end (85) of the inner detection target portion.

8. A differential voltage calculation unit (96) calculates a differential voltage (Vssub), which is the difference between the output voltage signal of the outer coil and the output voltage signal of the inner coil. A force calculation unit (98) calculates the force (Fz) acting on the rotating body in a direction perpendicular to the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to claim 7, comprising:

9. The receiving coil is When the excitation voltage is supplied to the excitation coil, a first coil (150) is provided which induces a voltage that is in phase with the voltage induced in the outer coil and the inner coil, When the excitation voltage is supplied to the excitation coil, a second coil (160) is provided which induces a voltage in the same phase as the induced voltage of the first coil, Includes, The first coil is provided on the outer side of the second coil in the radial direction, In a plan view of the outer coil, the inner coil, the first coil, and the second coil, the radial outer end and inner end of the first coil are located between the radial outer end and inner end of the outer detection target portion, and closer to the radial inner end of the outer detection target portion. In a plan view of the outer coil, the inner coil, the first coil, and the second coil, the radial outer end and inner end of the second coil are located between the radial outer end and inner end of the inner detection target portion, and closer to the radial outer end of the inner detection target portion. The first coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the outer detection target in the axial direction. The second coil outputs an AC voltage signal having an amplitude corresponding to the displacement of the inner detection target in the axial direction. A first combined voltage calculation unit (96) calculates a first combined voltage (Vsadd), which is the sum of the output voltage signal of the outer coil and the output voltage signal of the inner coil, A second combined voltage calculation unit (99) calculates a second combined voltage (Vcad), which is the sum of the output voltage signal of the first coil and the output voltage signal of the second coil, An angle calculation unit (97) calculates the rotation angle of the rotating body based on the first combined voltage calculated by the first combined voltage calculation unit and the second combined voltage calculated by the second combined voltage calculation unit, The detection device according to claim 7 or 8, comprising:

10. The detection device according to any one of claims 1 to 3, 5 to 8, wherein, in a front view of the outer coil and the inner coil, the radially inner portion of the outer coil and the radially outer portion of the inner coil overlap.

11. The machine is equipped with a motor (20) which serves as the power source for the rotation of the rotating body. The motor has a rotor (30) that includes a magnet unit (32) that forms a plurality of magnetic poles with alternating polarities in the circumferential direction, The detection device according to claim 4, wherein the angle calculation unit calculates the rotation angle of the rotor.

12. The receiving coil is A first portion (110P, 120P, 130P) that generates a voltage of first polarity across the receiving coil when the excitation voltage is supplied to the excitation coil, When the excitation voltage is supplied to the excitation coil, a second portion (110M, 120M, 130M) generates a voltage with a second polarity opposite to the first polarity at both ends of the receiving coil, It has, The receiving coil is In a plan view of the receiving coil, the first portion (110P, 120P) is provided on one side of the circumferential center of the receiving coil, and the second portion (110M, 120M) is provided on the other side, and the first portion and the second portion are arranged in the circumferential direction, or In a plan view of the receiving coil, the first portion (130P) and second portion (130M) on one side and the first portion and second portion on the other side are configured symmetrically with respect to the center of the receiving coil in the circumferential direction. The detection device according to any one of claims 1 to 3, 5 to 8.

13. The detection device according to any one of claims 1 to 3, 5 to 8, wherein the machine is a vehicle equipped with wheels as the rotating body.

14. The detection device according to claim 13, wherein the bearing is arranged such that the center position (Lb) of the bearing in the vehicle width direction is inward in the vehicle width direction than the center position (Lh) of the wheel constituting the wheel.

15. The detection device according to claim 14, which is dependent on claim 3, further comprising a correction unit that acquires the offset amount (Loff) between the center position of the wheel in the vehicle width direction and the center position of the bearing in the vehicle width direction, and corrects the force calculated by the force calculation unit based on the acquired offset amount.

16. The detection target unit is, The first detection target unit, A second detection target is provided at a position opposite to the first detection target in the axial direction, It has, The first detection target portion and the second detection target portion are configured such that recesses (183, 283) that are recessed in the axial direction and protrusions (182, 282) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The first detection target unit is arranged such that the recess and protrusion of the first detection target unit are directed toward the recess and protrusion of the second detection target unit. The receiving coil is A first intermediate coil (130A) is provided at a position opposite to the first detection target unit, A second intermediate coil (130B) is provided at a position opposite to the second detection target unit, Includes, When the excitation voltage is supplied to the excitation coil, the first intermediate coil and the second intermediate coil are configured such that a voltage in the same phase as the voltage induced in the second intermediate coil is induced in the first intermediate coil. A differential voltage calculation unit (95) calculates a differential voltage (Vcsub), which is the difference between the output voltage signal of the first intermediate coil and the output voltage signal of the second intermediate coil. A force calculation unit (95) calculates the force (Fy) acting on the rotating body in the axial direction based on the differential voltage calculated by the differential voltage calculation unit, The detection device according to claim 1, comprising:

17. In a detection device applied to a machine equipped with a rotating body (10), A bearing (50) rotatably supports the rotating body with respect to the base portion (42) of the machine, A first detection target portion (182, 183) extends in the circumferential direction of the bearing and forms an annular shape centered on the bearing, The second detection target portion (282, 283) extends in the circumferential direction and forms an annular shape centered on the bearing, The bearing comprises a planar receiving coil (130A, 130B) extending in the radial direction, Excitation coils (100, 100A, 100B) to which AC excitation voltage is supplied, Equipped with, The first detection target unit and the second detection target unit are provided to rotate in conjunction with the rotation of the rotating body. The second detection target unit is provided at a position opposite to the first detection target unit in the axial direction of the bearing, The first detection target portion and the second detection target portion are configured such that recesses (183, 283) that are recessed in the axial direction and protrusions (182, 282) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction. The first detection target unit is arranged such that the recess and protrusion of the first detection target unit are directed toward the recess and protrusion of the second detection target unit. The receiving coil is A first intermediate coil (130A) is fixed to the base portion and is provided at a position facing the first detection target portion in the axial direction, A second intermediate coil (130B) is fixed to the base portion and is provided at a position facing the second detection target portion in the axial direction, Includes, When the excitation voltage is supplied to the excitation coil, the first intermediate coil and the second intermediate coil are configured such that a voltage in the same phase as the voltage induced in the second intermediate coil is induced in the first intermediate coil. A differential voltage calculation unit (95) calculates a differential voltage (Vcsub), which is the difference between the output voltage signal of the first intermediate coil and the output voltage signal of the second intermediate coil. A force calculation unit (95) calculates the force (Fy) acting on the rotating body in the axial direction based on the differential voltage calculated by the differential voltage calculation unit, A detection device equipped with the following features.

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