Vehicle detection device

Abstract

To provide a vehicular detection device capable of enhancing accuracy of detecting displacement.SOLUTION: A detection device comprises: a stator base portion 42 fixed to a vehicle body of a vehicle; and a bearing 50. The bearing 50 has an outer ring 51, an inner ring 52, and rolling elements 53 provided between the outer ring 51 and the inner ring 52, and supports a wheel so as to be rotatable relative to the stator base portion 42. The inner ring 52 is fixed to the wheel, and the outer ring 51 is fixed to the stator base portion 42. The detection device comprises: a disk-shaped race portion 80 that is fixed to the inner ring 52 and extends radially outward of the bearing 50; and a detection unit 90. The detection unit 90 is provided at a position, which is away from the bearing 50 in a radial direction and faces the race portion 80 in an axial direction of the bearing 50, on the stator base portion 42.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0005]

[0001] The present invention relates to a vehicle detection device.

Background Art

[0002] Conventionally, as described in Patent Document 1, a bearing unit that rotatably supports a hub fixed to a wheel with respect to a vehicle body is known. The bearing unit 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 the running control of the vehicle be performed based on the force (for example, lateral force) acting on the wheel.

[0003] As a configuration for detecting the force acting on the wheel, Patent Document 1 describes a detected ring provided on the inner peripheral side of the inner ring and fixed to the hub, and a displacement sensor unit. The detected ring includes a cylindrical portion and a bent portion that bends radially outward from an axial end portion of the cylindrical portion. The tip of the displacement sensor unit is disposed on the inner peripheral side of the inner ring. A displacement measuring element that faces the bend in the axial direction of the bearing unit is provided at the tip of the displacement sensor unit.

[0004] When a force acts on the wheel, the inclination of the central axis of the inner ring with respect to the central axis of the outer ring increases. In this case, the distance in the axial direction between the displacement measuring element and the bent portion changes. This change in distance is detected as the axial displacement of the bent portion. Then, the detected displacement is converted into the force acting on the wheel.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Since the bent section is located inside the bearing unit, the axial displacement of the bent section when force is applied to the wheel is small. In this case, there is a concern that the accuracy of displacement detection may deteriorate.

[0007] The primary objective of this invention is to provide a vehicle detection device that can improve the accuracy of displacement detection. [Means for solving the problem]

[0008] The present invention comprises a base portion fixed to the vehicle body, A bearing comprising an outer ring member, an inner ring member, and rolling elements provided between the outer ring member and the inner ring member, which rotatably supports the wheel of the vehicle relative to the base portion, Of the outer ring member and the inner ring member, the first bearing member is fixed to the wheel, and the other, the second bearing member, is fixed to the base portion. A disc-shaped detection rotating part is provided to rotate integrally with the first bearing member and extends radially outward from the bearing relative to the first bearing member, The base portion includes a displacement detection unit which is provided in a non-contact state with the detection rotating unit at a position away from the bearing in the radial direction and facing the detection rotating unit in the axial direction of the bearing, and which outputs a signal corresponding to the axial displacement of the detection rotating unit.

[0009] In this invention, a detection rotating part is provided so as to rotate integrally with the first bearing member that constitutes the bearing. Therefore, the detection rotating part rotates integrally with the wheel fixed to the first bearing member.

[0010] Here, when a lateral force acts on the wheel, the axial displacement of the detection rotating part increases as it moves radially outward from the first bearing member. By providing the displacement detection unit at a position where the displacement is large, the accuracy of displacement detection can be improved. Therefore, in the present invention, the displacement detection unit is provided in the base portion at a position radially away from the bearing and axially opposite to the detection rotating part. As a result, compared to a configuration in which the displacement detection unit is provided inside the bearing, for example, the change in the output signal (e.g., the amplitude of the output signal) of the displacement detection unit in response to changes in the axial displacement of the detection rotating part can be made larger. This improves the accuracy of displacement detection by the displacement detection unit, and for example, improves the accuracy of calculating the lateral force based on the detected displacement. [Brief explanation of the drawing]

[0011] [Figure 1] A longitudinal cross-sectional view of the wheel according to the first embodiment. [Figure 2] Plan view of the racing section. [Figure 3] This diagram shows the state in which the inner wheel is tilted relative to the outer wheel when a lateral force is applied to the tire. [Figure 4] A diagram showing the detection unit. [Figure 5] A diagram showing the electrical configuration of the detection unit and processing unit. [Figure 6] Projection view of the excitation coil and the first and second receiving coils in a plan view of a multilayer substrate. [Figure 7] A diagram showing the wiring pattern and vias formed on the first layer of a multilayer substrate. [Figure 8] A diagram showing the wiring pattern and vias formed on the second layer of a multilayer substrate. [Figure 9] A diagram showing the wiring pattern and vias formed in the third layer of a multilayer substrate. [Figure 10] A diagram showing the wiring pattern and vias formed in the fourth layer of a multilayer substrate. [Figure 11] A diagram illustrating the principle of detecting displacement and rotation angle. [Figure 12] A diagram illustrating the principle of detecting displacement and rotation angle. [Figure 13] Plan view of the simplified second receiving coil. [Figure 14] Diagram showing the output voltage signal of the receiving coil and the transition of the envelope of this signal. [Figure 15] Diagram showing the transition of the envelopes of the output voltage signals of the first and second receiving coils. [Figure 16] Characteristic diagram showing the relationship between the maximum amplitude value, displacement, and lateral force of the output voltage signal. [Figure 17] Plan view of the race section according to a modified example of the first embodiment. [Figure 18] Perspective view of the race section according to a modified example of the first embodiment. [Figure 19] Plan view of the race section according to a modified example of the first embodiment. [Figure 20] Diagram showing the race section, detection unit, and processing unit according to the second embodiment. [Figure 21] Diagram showing the transition of the envelopes of the output voltages of each detection unit, etc. [Figure 22] Diagram showing the race section, detection unit, and processing unit according to the third embodiment. [Figure 23] Diagram showing the race section and detection unit according to the fourth embodiment. [Figure 24] Vertical cross-sectional view of a wheel according to the fifth embodiment. [Figure 25] Vertical cross-sectional view of a wheel according to the sixth embodiment.

Mode for Carrying Out the Invention

[0012] <First Embodiment> Hereinafter, a first embodiment in which a vehicle detection device according to the present invention is embodied will be described with reference to the drawings. The detection device of this embodiment is configured to be able to calculate the lateral force acting on a wheel (driving wheel) provided with an in-wheel motor. The vehicle is, for example, a passenger four-wheel vehicle having two front wheels and two rear wheels. However, the vehicle is not limited to this, and may be a vehicle other than four wheels, such as a two-wheel vehicle. Further, the use of the vehicle is not limited to passenger use.

[0013] As shown in Figure 1, the wheel comprises 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 surface provided 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 the "first bearing member," an inner ring 52 corresponding to the "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 disc 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 power storage unit electrically connected to the inverter. The power storage unit is located in the vehicle body and is, for example, 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 located in the vehicle body or may be built into the in-wheel motor 20.

[0022] The inner space of the wheel 10 is provided with a disc-shaped race section 80 corresponding to a "detection rotation section" and a detection unit 90 corresponding to a "displacement detection section". The race section 80 and the detection unit 90 are used to calculate the rotation angle (specifically, the electrical angle or mechanical angle) of the rotor 30 of the in-wheel motor 20, the rotational speed of the wheel, and the lateral force Fy acting between the contact surface (ground) GL and the wheel (tire 13). For example, the calculated rotation angle (electrical angle) is used in the control device for switching control of the inverter, and the rotational speed of the wheel and the lateral force are used in the control device for vehicle driving control.

[0023] As shown in Figures 1 and 2, the race portion 80 is disc-shaped and made of a metal material (for example, iron or aluminum). A through hole is formed in the center of the race portion 80. The peripheral edge of the through hole in the race portion 80 is a bent portion 80a that bends in the direction of the disc portion 12. The bent portion 80a is fitted into the through hole formed in the center of the flat plate portion 33 of the rotor 30. The race portion 80 is fixed 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. As a result, the race portion 80 and the inner ring 52 are coaxial. The race portion 80, rotor 30, and wheel 10 rotate as a single unit.

[0024] The radially outer end of the race portion 80 faces the protruding portion 45 of the stator base portion 42. As shown in Figure 2, the radially outer end of the race portion 80 alternately has a shielding portion 81, which is a metal part, and a notch 82 that penetrates the race portion 80 in the thickness direction, in the circumferential direction. The shielding portion 81 and the notch 82 form an annular "detection target portion". In this embodiment, the circumferential length L1 of the shielding portion 81 is equal to the circumferential length L2 of the notch 82. Also, in the example shown in Figure 2, eight sets of shielding portions 81 and notches 82 are provided. Note that LCi shown in Figure 2 indicates the central axis of the inner ring 52.

[0025] The detection unit 90 is a so-called eddy current type inductive sensor. As shown in Figures 2, 4, and 5, 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 race section 80 as seen from the wheel 10 side. Figure 4 is a diagram showing the substrate 91 as seen from the wheel 10 side. 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.

[0026] As shown in Figures 1 and 5, the circuit unit 93 is electrically connected to the processing unit 70. More specifically, a through hole 46 is formed in the protruding portion 45, and the processing unit 70 and the circuit unit 93 are electrically connected via wiring inserted through the through hole 46. The processing unit 70 may be provided on the vehicle body or built into the in-wheel motor 20.

[0027] The coil section 92 comprises an excitation coil 100, a first receiving coil 110, and a second receiving coil 120. Each of the coils 100, 110, and 120 is a planar coil. The circuit section 93 is composed of an integrated circuit. As shown in Figure 5, the circuit section 93 comprises 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, a voltage with the same or equivalent frequency as the excitation voltage is induced in the first receiving coil 110 and the second receiving coil 120. The receiving circuit 95 detects the voltage across each of the receiving coils 110 and 120 as an output voltage signal.

[0028] 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 with respect to the central axis LCo of the outer ring 51 increases, as shown in Figure 3. In this case, the axial distance between each receiving coil 110, 120 and the race section 80 changes, and the amplitude of the output voltage signal of each receiving coil 110, 120 changes. Based on this amplitude change, the detection unit 90 calculates the axial displacement ΔL of the race section 80, and calculates the lateral force Fy based on the calculated displacement ΔL.

[0029] Next, the coil section 92 will be described using Figures 6 to 10. In this embodiment, the substrate 91 is a multilayer substrate (specifically, a four-layer substrate), and the excitation coil 100 and each receiving coil 110, 120 constituting the coil section 92 are made up of wiring patterns on the multilayer substrate. Figures 7 to 10 show the wiring patterns formed on each layer when the substrate 91 is viewed from the lace section 80 side. Figure 6(a) is a diagram showing the wiring patterns of the second to fourth layers projected onto the wiring pattern of the first layer.

[0030] First, the excitation coil 100 will be described. As shown in Figures 7 and 8, the excitation coil 100 is formed in the first and second layers of the substrate 91, which are adjacent in the thickness direction. The wiring patterns of each layer are electrically connected by conductors filled in the excitation-side vias VI. The first layer has a wiring pattern consisting of a first excitation end 101 electrically connected to the excitation circuit 94, and a first excitation pattern 102 formed by making multiple (3) clockwise turns from the first excitation end 101 to the excitation-side via VI. The second layer has a second excitation end 103 electrically connected to the excitation circuit 94, and a second excitation pattern 104 formed by making multiple (3) counterclockwise turns from the second excitation end 103 to the excitation-side via VI. As a result, a 6-turn planar coil excitation coil 100 is formed on the substrate 91. The excitation coil 100 has an arc shape extending in the circumferential direction of the outer ring 51.

[0031] Next, the first receiving coil 110 will be described. The first receiving coil 110 is formed in the 1st to 4th layers, as shown in Figures 7 to 10. As shown in Figure 9, the 3rd layer has a first receiving end 111 which is electrically connected to the receiving circuit 95. The first end of the pattern 112 of the 1st layer is connected to the first receiving end 111 via the first A via VA1. The first end of the pattern 113 of the 2nd layer is connected to the second end of the pattern 112 via the second A via VA2. The first end of the pattern 115 of the 1st layer is connected to the second end of the pattern 113 via the third A via VA3, pattern 114, and fourth A via VA4. The first end of the pattern 116 of the 2nd layer is connected to the second end of the pattern 115 via the fifth A via VA5. The second receiving end 118 of the 4th layer is connected to the second end of the pattern 116 via the sixth A via VA6, pattern 117, and seventh A via VA7. The second receiving end 118 is connected to the receiving circuit 95. The receiving circuit 95 detects the potential difference between the first receiving end 111 and the second receiving end 118 as the first output voltage signal v1.

[0032] As shown in Figure 6(a), the first receiving coil 110 is located in the region surrounded by the excitation coil 100 in a plan view of the substrate 91. Furthermore, when an excitation voltage is supplied to the excitation coil 100, the first receiving coil 110 consists of a first part that generates a voltage of first polarity between the first receiving end 111 and the second receiving end 118 of the first receiving coil 110, and a second part that generates a voltage of second polarity which is the opposite polarity to the first polarity. Specifically, as shown in Figure 6(b), in a plan view of the substrate 91, the central part of the circumferential direction of the first receiving coil 110 is a first part 110A with one turn, and both ends of the first part 110A of the first receiving coil 110 are second parts 110B with the same number of turns (1 turn) as the first part 110A. As a result, the pattern shapes of the first and second portions 110A and 110B on one side and the pattern shapes of the first and second portions 110A and 110B on the other side of the first receiving coil 110 are symmetrical with respect to the central axis Lt in the circumferential direction of the first receiving coil 110.

[0033] Next, the second receiving coil 120 will be described. The second receiving coil 120 is formed in the 1st to 4th layers, as shown in Figures 7 to 10. As shown in Figure 9, the 3rd layer has a 3rd receiving end 121 which is electrically connected to the receiving circuit 95. The 3rd receiving end 121 is connected to the 1st end of the pattern 122 of the 2nd layer via the 1st B via VB1. The 2nd end of the pattern 122 is connected to the 1st end of the pattern 123 of the 1st layer via the 2nd B via VB2. The 2nd end of the pattern 123 is connected to the 1st end of the pattern 125 of the 1st layer via the 3rd A via VA3, pattern 124, and 4th B via VB4. The 2nd end of the pattern 125 is connected to the 1st end of the pattern 126 of the 2nd layer via the 5th B via VB5. The 4th receiving end 128 of the 4th layer is connected to the 2nd end of the pattern 126 via the 6th B via VB6, pattern 127, and 7th B via VB7. The fourth receiving end 128 is connected to the receiving circuit 95. The receiving circuit 95 detects the potential difference between the third receiving end 121 and the fourth receiving end 128 as the second output voltage signal v2.

[0034] As shown in Figure 6(a), the second receiving coil 120 is located in the region surrounded by the excitation coil 100 in a plan view of the substrate 91. The circumferential length of the second receiving coil 120 is the same as the circumferential length of the first receiving coil 110. The radial length of the second receiving coil 120 is the same as the radial length of the first receiving coil 110.

[0035] In a plan view of the substrate 91, the circumferential ends of the second receiving coil 120 are the same as the circumferential ends of the first receiving coil 110. Also, in a plan view of the substrate 91, the radially outer end of the second receiving coil 120 and the radially outer end of the first receiving coil 110 lie on concentric circles centered on the central axis LCo of the outer ring 51. Also, in a plan view of the substrate 91, the radially inner end of the second receiving coil 120 and the radially inner end of the first receiving coil 110 lie on concentric circles centered on the central axis LCo.

[0036] As shown in Figure 6(c), the second receiving coil 120, like the first receiving coil 110, is composed of a first part 120A and a second part 120B. In a plan view of the substrate 91, one side of the second receiving coil 120 with respect to the circumferential central axis Lt is the first part 120A, and the other side is the second part 120B.

[0037] In the first receiving coil 110 and the second receiving coil 120, the circumferential length from the central axis Lt to the circumferential end is the same as the circumferential length L1 of the shielding portion 81 and the notch 82.

[0038] Next, using Figures 11 to 16, we will explain the principle by which the detection unit 90 can detect displacement and rotation angle.

[0039] First, we will explain the outline of this principle using Figures 11 and 12. As shown in Figure 11, 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 across the ends of the receiving coil.

[0040] Figure 12 shows a state in which a portion of the receiving coil is covered by the metal shielding portion. Eddy currents flow in the portion of the shielding portion 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 across the ends of the receiving coil is proportional to the area of ​​the receiving coil that is not covered by the shielding portion.

[0041] Based on the explanations in Figures 11 and 12, the detection principle will be explained using Figures 13 and 14, with the second receiving coil 120 as an example. Figures 13 and 14 show the second receiving coil 120 and shielding portion 81, as shown in Figure 6, etc., with the circumferential direction being linear. Figure 14 shows the relative positional relationship between the second receiving coil 120 and the shielding portion 81, and the transition of the second output voltage signal v2 of the second receiving coil 120.

[0042] In Figures 13 and 14, the direction in which current flows from the second receiving end 118 to the first receiving end 111 (I+) is referred to as the positive direction, and the direction in which current flows from the first receiving end 111 to the second receiving end 118 (I-) is referred to as the negative direction. Also, in Figures 13 and 14, the magnetic flux from the excitation coil 100 passes from the front to the back of the page.

[0043] At time t1 in Figure 14, the central half of the first part 120A and the central half of the second part 120B are covered by the shielding part 81. A voltage that tends to induce a current in the positive direction is induced in the first part 120A, and a voltage that tends to induce a current in the negative direction is induced in the second part 120B. As a result, the induced voltage generated in the first part 120A and the induced voltage generated in the second part 120B cancel each other out, and the amplitude of the second output voltage signal v2 becomes 0.

[0044] At time t2, the second part 120B of the first part 120A is covered by the shielding part 81. In this case, a voltage that attempts to induce a current in the positive direction is induced in the first part 120A, and the induced voltage in the second part 120B becomes 0. As a result, the amplitude of the second output voltage signal v2 becomes the maximum value on the first polarity (positive polarity) side. This maximum value increases as the race part 80 approaches the second receiving coil 120.

[0045] At time t3, the end half of the first part 120A and the end half of the second part 120B are covered by the shielding part 81. A voltage that tends to induce a current in the positive direction is induced in the first part 120A, and a voltage that tends to induce a current in the negative direction is induced in the second part 120B. As a result, the induced voltage generated in the first part 120A and the induced voltage generated in the second part 120B cancel each other out, and the amplitude of the second output voltage signal v2 becomes 0.

[0046] At time t4, the first part 120A of the second part 120B is covered by the shielding part 81. In this case, a voltage that tends to cause current to flow in the negative direction is induced in the second part 120B, and the induced voltage of the first part 120A becomes 0. As a result, the amplitude of the second output voltage signal v2 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 race part 80 approaches the second receiving coil 120.

[0047] In this embodiment, shielding portions 81 and notches 82 are alternately formed at the radially outer end of the race portion 80. Therefore, during the rotation of the rotor 30, the amplitude of the second output voltage signal v2 of the second receiving coil 120 changes periodically, and as shown by the dashed lines in Figures 14 and 15, the envelope of the second output voltage signal v2 (hereinafter, second envelope ENV2) becomes sinusoidal. For example, by relating the circumferential spacing of the magnetic pole positions of the magnet unit 32 with the circumferential lengths of the shielding portions 81 and notches 82, the amplitude or envelope can be associated with the electrical angle θe.

[0048] In this embodiment, when an excitation voltage is supplied to the excitation coil 100, the phase difference between the second output voltage signal v2 of the second receiving coil 120 and the first output voltage signal v1 of the first receiving coil 110 is 90 degrees. Therefore, as shown by the dashed line in Figure 15, the phase difference between the envelope of the first output voltage signal v1 (hereinafter referred to as the first envelope ENV1) and the second envelope ENV2 is also 90 degrees.

[0049] As shown in Figure 16, the amplitudes of the first and second envelopes ENV1 and ENV2 increase as the race section 80 approaches the first and second receiving coils 110 and 120. Taking the first envelope ENV1 as an example, the receiving circuit 95 outputs the amount of deviation of the actual amplitude of the first envelope ENV1 from the amplitude of the first envelope ES1 in the reference state as a first displacement signal to the processing unit 70. 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. In this embodiment, the receiving circuit 95 is configured such that the first displacement signal in the reference state is 0. The first displacement signal has a positive polarity when the upper end of the race section 80 approaches the first and second receiving coils 110 and 120 from its position in the reference state. The first displacement signal increases in the positive direction as the race section 80 approaches the first and second receiving coils 110 and 120 from its position in the reference state. On the other hand, the first displacement signal becomes negative when the upper end of the race section 80 moves away from the first and second receiving coils 110 and 120 relative to its position in the reference state. The first displacement signal becomes larger in the negative direction as the upper end of the race section 80 moves away from the first and second receiving coils 110 and 120 relative to its position in the reference state. The first displacement signal is updated each time the maximum amplitude on the positive side and the maximum amplitude on the negative side of the first envelope ENV1 appear. The receiving circuit 95 outputs the amount of deviation of the actual amplitude of the second envelope ENV2 from the amplitude of the second envelope ES2 in the reference state as the second displacement signal to the processing unit 70. In this embodiment, the receiving circuit 95 is configured such that the second displacement signal in the reference state is 0. Using the relationships described above, the displacement calculation unit 71 of the processing unit 70 calculates the axial displacement ΔL of the race section 80 based on the first displacement signal or the second displacement signal. More specifically, the displacement calculation unit 71 calculates the displacement ΔL based on the map information or mathematical formula information to which the displacement signal and displacement ΔL are related.

[0050] As shown in Figure 16, the larger the displacement ΔL, the larger the lateral force Fy. Utilizing this relationship, the lateral force calculation unit 72, which constitutes the processing unit 70, calculates the lateral force Fy based on the calculated displacement ΔL and map information or mathematical formula information relating the displacement ΔL and the lateral force Fy. When the lateral force Fy is a positive value, a lateral force acts on the wheel in the direction outward in the vehicle width direction, and when the lateral force Fy is a negative value, a lateral force acts on the wheel in the direction inward in the vehicle width direction. For example, using the first displacement signal, the lateral force calculation unit 72 may calculate the lateral force Fy based on the first displacement signal and map information or mathematical formula information relating the first displacement signal and the lateral force Fy. The calculation of the lateral force Fy based on the displacement signal and map information or mathematical formula information can be similarly applied in the following embodiments.

[0051] The angle calculation unit 73, which constitutes the processing unit 70, calculates the rotation angle (e.g., electrical angle θe) of the rotor 30 based on at least one of the first output voltage signal v1 and the second output voltage signal v2.

[0052] Specifically, for example, the angle calculation unit 73 can calculate the electrical angle θe based on the first envelope ENV1 or the second envelope ENV2. This calculation method is based on the fact that the envelope contains information indicating the change in the amplitude of the output voltage signal, and that the amplitude of the output voltage signal depends on the rotation angle.

[0053] Furthermore, for example, the angle calculation unit 73 can calculate the electrical angle θe by taking the first output voltage signal v1, the second output voltage signal v2, and the excitation voltage vr as inputs and using synchronous detection and a low-pass filter. This calculation method is a digital tracking method and is described, for example, in paragraphs 0028 to 0030 of the specification of Japanese Patent Application Publication No. 2015-073407.

[0054] According to the embodiment described in detail above, the following effects can be obtained.

[0055] A detection unit 90 is provided in the stator base portion 42 at a position radially away from the bearing 50 and axially opposite to the radial end of the race portion 80. The portion of the race portion 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 race portion 80 that faces the detection unit 90 in the axial direction can be increased. As a result, the detection accuracy of the displacement ΔL 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.

[0056] Because the in-wheel motor 20 is configured as an outer rotor type, the radial end of the race portion 80 can be positioned at a location far enough away radially from the bearing 50. This improves the accuracy of displacement ΔL detection.

[0057] The first receiving coil 110 and the second receiving coil 120 are 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 factors associated with energizing the stator winding 41 on the induced voltage of the first receiving coil 110 and the second receiving coil 120. As a result, the detection accuracy of displacement ΔL and rotation angle can be improved.

[0058] <Modified form of the first embodiment> The race section is not limited to the configuration shown in Figure 1, etc., but may also have configurations such as (A) and (B) below.

[0059] (A) As shown in Figure 17, the lace portion 83 is alternately provided with shielding portions 85 and openings 84 that penetrate the lace portion in the circumferential direction. Note that 83a in Figure 17 corresponds to the bent portion 80a shown in Figures 1 and 2. Also, the circumferential length of the opening 84 corresponds to the circumferential length of the notch 82 in Figure 2.

[0060] (B) As shown in Figures 18 and 19, the lace portion 8 6 The race section 8 6A protrusion 87 that projects from the flat surface of the inner ring 52 in the axial direction, and a race portion 8 6 The rotor 30 has alternating recesses 88 that protrude axially from the flat surface and recesses 88 that are recessed in the axial direction relative to the convex portion 87 in the inner ring 52. The circumferential length of the convex portion 87 corresponds to the circumferential length of the shielding portion 81 in Figure 2, and the circumferential length of the recess 88 corresponds to the circumferential length of the notch 82 in Figure 2. Due to the provision of the recesses 88 and convex portion 87, during the rotation of the rotor 30, each receiving coil 110, 120 and the race portion 8 6 The axial distance between the points changes. This change can be used to detect the displacement ΔL, similar to the first embodiment. The detection unit 90 may be positioned opposite the lower end of the race portion 80. Alternatively, the detection unit 90 may be positioned on the disc portion 12 side relative to the race portion 80.

[0061] <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 20, a first detection unit 90A and a second detection unit 90B are provided as detection units. The coil portion 92 (first and second receiving coils 110 and 120) of the first detection unit 90A is provided at a position on the protruding portion 45 of the stator base portion 42 that faces the upper end of the race portion 80 in the axial direction of the inner ring 52. The coil portion 92 (first and second receiving coils 110 and 120) of the second detection unit 90B is provided at a position on the protruding portion 45 that faces the lower end of the race portion 80 in the axial direction of the inner ring 52. The substrates 91 of the first and second detection units 90A and 90B are arranged on the same side in the axial direction with respect to the race portion 80. In Figure 20, HL indicates the horizontal axis passing through the central axis LSi of the inner ring 52.

[0062] During the rotation of the rotor 30, the detection units 90A and 90B are configured and arranged such that the phase difference between the first and second output voltage signals v1B and v2B of the first and second receiving coils 110 and 120 of the first and second receiving coils 110 and 120 of the first detection unit 90A and the first and second output voltage signals v1A and v2A of the first and second receiving coils 110 and 120 of the first detection unit 90A becomes zero.

[0063] The processing unit 70 includes a differential amplifier circuit AP. The differential amplifier circuit AP amplifies the difference between the first output voltage signal v1A of the first detection unit 90A and the first output voltage signal v1B of the second detection unit 90B and outputs it as the first amplified signal vt1. The differential amplifier circuit AP also amplifies the difference between the second output voltage signal v2A of the first detection unit 90A and the second output voltage signal v2B of the second detection unit 90B and outputs it as the second amplified signal vt2. In the angle calculation unit 73, the first and second amplified signals vt1 and vt2 are used to calculate the rotation angle instead of the first and second output voltage signals v1 and v2. Alternatively, the rotation angle may be calculated based on the first and second output voltage signals v1A and v2A of the first detection unit 90A, or the first and second output voltage signals v1B and v2B of the second detection unit 90B. Furthermore, the displacement calculation unit 71 calculates the amplitude of the envelope of the first amplified signal vt1 as the first displacement signal, and the amplitude of the envelope of the second amplified signal vt2 as the second displacement signal. Because differential amplification is used, the amplitude change of the output voltage signals of each receiving coil 110, 120 can be increased in response to the change in axial displacement between the coil section 92 and the race section 80. In other words, the sensitivity of the inductive sensor can be increased. This makes it possible to improve the detection accuracy of the displacement ΔL.

[0064] The output signals of the differential amplifier circuit AP, etc., will be explained below using Figure 21. Figure 21(a) shows the transition of the envelope ENV1A of the first output voltage signal v1A in the first detection unit 90A, and Figure 21(b) shows the transition of the envelope ENV1B of the first output voltage signal v1B in the second detection unit 90B. Figure 21(c) shows the transition of the envelope ENV1t of the first amplified signal vt1 (=v1A-v1B).

[0065] The phase difference between the first output voltage signal v1A of the first detection unit 90A and the first output voltage signal v1B of the second detection unit 90B is 0. Also, when no lateral force is acting on the wheel, the amplitude of the first output voltage signal v1A of the first detection unit 90A and the amplitude of the first output voltage signal v1B of the second detection unit 90B are the same. As a result, as shown by the dashed lines in the figure, the amplitudes of each envelope ENV1A and ENV1B become the same, and the first amplified signal vt1 and the first displacement signal become 0.

[0066] On the other hand, when a lateral force acting on the wheel in the direction of the vehicle width is directed outward, the inner ring 52 tilts relative to the outer ring 51 such that the upper end of the race portion 80 moves closer to the stator base portion 42 and the lower end moves closer to the wheel 10. As a result, the amplitude of the first output voltage signal v1A of the first detection unit 90A increases, and the amplitude of the first output voltage signal v1B of the second detection unit 90B decreases. Consequently, as shown by the solid line in the figure, the amplitude of the envelope ENV1A of the first output voltage signal v1A in the first detection unit 90A increases, and the amplitude of the envelope ENV1B of the first output voltage signal v1B in the second detection unit 90B decreases. Therefore, the amplitude of the envelope ENV1t of the first amplified signal vt1 increases. Based on the above, the displacement calculation unit 71, which constitutes the processing unit 70, calculates the amplitudes of the envelopes of the first and second amplified signals vt1 and vt2 as the first and second displacement signals, and calculates the axial displacement ΔL of the race unit 80 based on either of the calculated first and second displacement signals.

[0067] The coil portion 92 of the first detection unit 90A is positioned opposite the upper end of the race portion 80, and the coil portion 92 of the second detection unit 90B is positioned opposite the lower end of the race portion 80. When a lateral force acts on the wheel, the axial displacement of the upper and lower ends of the race portion 80 becomes large. Therefore, this arrangement allows the amplitude of the output voltage signals of the receiving coils 110 and 120 of each detection unit 90A and 90B to be increased, thereby improving the detection accuracy of the displacement ΔL.

[0068] The circuit boards 91 of the first and second detection units 90A and 90B are positioned on the same axial side with respect to the race section 80. When the direction of the lateral force acting on the wheel is outward in the vehicle width direction, the inner ring 52 tilts relative to the outer ring 51 such that the upper end of the race section 80 approaches the stator base section 42 and the lower end approaches the wheel 10. In this case, the amplitude of the output voltage signals of each receiving coil 110, 120 of the first detection unit 90A increases, and the amplitude of the output voltage signals of each receiving coil 110, 120 of the second detection unit 90B decreases. In other words, the decrease in the amplitude of the output voltage signal on the second detection unit 90B side can be compensated for by the increase in the amplitude of the output voltage signal on the first detection unit 90A side.

[0069] On the other hand, if the direction of the lateral force acting on the wheel is directed inward in the vehicle width direction, the inner wheel 52 tilts relative to the outer wheel 51 such that the upper end of the race portion 80 approaches the wheel 10 side and the lower end approaches the stator base portion 42 side. In this case, the amplitude of the output voltage signals of each receiving coil 110, 120 of the first detection unit 90A decreases, and the amplitude of the output voltage signals of each receiving coil 110, 120 of the second detection unit 90B increases. In other words, the decrease in the amplitude of the output voltage signal on the first detection unit 90A side can be compensated for by the increase in the amplitude of the output voltage signal on the second detection unit 90B side.

[0070] In this configuration, where the circuit boards 91 of the first and second detection units 90A and 90B are positioned on the same side as the race section 80, the amplitude of the output voltage signal can be maintained as much as possible, regardless of whether the direction of the lateral force acting on the wheel is inward or outward in the vehicle width direction. As a result, the detection accuracy of the displacement ΔL can be maintained.

[0071] <Modified form of the second embodiment> The second detection unit 90B may be positioned on the opposite side of the race section 80 from the first detection unit 90A.

[0072] <Third Embodiment> The third embodiment will now be described, focusing on the differences from the second embodiment, with reference to the drawings. In this embodiment, as shown in Figure 22, the substrate 91 and coil portion 92 of the second detection unit 90B are located on the opposite side of the race portion 80 from the substrate 91 and coil portion 92 of the first detection unit 90A, in the direction of the central axis LCo of the outer ring 51. In other words, the first detection unit 90A and the second detection unit 90B are located opposite the upper end of the race portion 80. Figure 22 is a view of the race portion 80 and each detection unit 90A, 90B from above the race portion 80. In this embodiment as well, the detection units 90A and 90B are configured and arranged such that, during the rotation of the rotor 30, the phase difference between the first and second output voltage signals v1A and v2A of the first and second receiving coils 110 and 120 of the first detection unit 90A and the first and second output voltage signals v1B and v2B of the first and second receiving coils 110 and 120 of the second detection unit 90B becomes zero. The angle calculation unit 73 calculates the rotation angle in the same manner as in the second embodiment, and the displacement calculation unit 71 calculates the first and second displacement signals in the same manner as in the second embodiment.

[0073] According to the embodiment described above, the same effects as those of the second embodiment can be achieved.

[0074] <Modified form of the third embodiment> The first detection unit 90A and the second detection unit 90B may be provided in positions facing the lower end of the race portion 80.

[0075] <Fourth Embodiment> The fourth 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 23, the coil section 92 (first and second receiving coils 110 and 120) is positioned to straddle the horizontal axis HL, which passes through the rotation center of the race section 80 (the central axis LCi of the inner ring 52). As a result, the circumferential centers of the first and second receiving coils 110 and 120 are shifted upward with respect to the horizontal axis HL. This arrangement method will now be explained using the second receiving coil 120 as an example.

[0076] As described above, due to the relative positional relationship between the second receiving coil 120 and the shielding portion 81, the induced voltage generated in the first portion 120A of the second receiving coil 120 and the induced voltage generated in the second portion 120B cancel each other out. In this case, the second output voltage signal v2 of the second receiving coil 120 becomes 0. As the cancellation state is resolved, the amplitude of the second output voltage signal v2 increases. However, the axial displacement of the race portion 80 near the horizontal axis HL is smaller than that of the radial end of the race portion 80. For this reason, in a configuration in which the detection unit 90 is provided straddling the horizontal axis HL, the amplitude of the second output voltage signal v2 of the second receiving coil 120 tends to be small.

[0077] Therefore, in this embodiment, the circumferential centers of the first and second receiving coils 110 and 120 are positioned upward with respect to the horizontal axis HL. This makes it possible to maximize the axial displacement between the second receiving coil 120 and the race section 80 when the inner ring 52 is inclined relative to the outer ring 51. As a result, the detection accuracy of the displacement ΔL can be improved.

[0078] <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 24, a configuration is adopted that allows for a smaller degree of coaxiality between the rotor 30, the race section 80, and the bearing 50. In Figure 24, components that are the same as or corresponding to those shown in Figure 1, etc., are denoted by the same reference numerals for convenience. In addition, the race section 80 of this embodiment does not have a bent portion 80a.

[0079] A through hole 33a is formed in the radial center of the flat plate portion 33 that constitutes the rotor 30. On the inner surface of the flat plate portion 33 in the vehicle width direction, an annular stepped portion 33b is formed, extending radially outward from the radially inner end. The inner surface of the stepped portion 33b in the vehicle width direction is a flat surface. An annular positioning portion 33c is formed at the radially inner end of the stepped portion 33b, projecting inward in the vehicle width direction.

[0080] A through hole 80b is formed in the radial center of the race portion 80. With the flat surface of the race portion 80 in contact with the flat surface of the stepped portion 33b, the positioning portion 33c is fitted into the through hole 80b of the race portion 80. As a result, the rotational axis of the rotor 30 and the rotational axis of the race portion 80 are made coaxial.

[0081] The inner radial end of the flange portion 52b of the inner ring 52 has an annular bearing-side stepped portion 52c that protrudes outward in the vehicle width direction. The portion of the flat plate portion 33 that is radially inward of the positioning portion 33c has an annular recess 33d that is recessed outward in the vehicle width direction. By fitting the bearing-side stepped portion 52c into the recess 33d, the central axis of the inner ring 52, the rotational central axis of the rotor 30, and the rotational central axis of the race portion 80 are made coaxial. In particular, in this embodiment, the flat surface on the outer side in the vehicle width direction of the flange portion 52b is in contact with the flat surfaces of the race portion 80 and the positioning portion 33c. This makes it possible to suitably reduce the coaxiality of the rotational central axis of the rotor 30, the rotational central axis of the race portion 80, and the central axis of the inner ring 52.

[0082] First through-holes are formed in the flat plate portion 33, the race portion 80, and the flange portion 52b, extending axially. Multiple first through-holes are formed in a circumferential direction (for example, at equal intervals in the circumferential direction). A bolt 200 is inserted through each first through-hole. The bolt 200 is inserted into the first through-hole with its head facing outward in the vehicle width direction and its shaft facing inward in the vehicle width direction. In this inserted state, the male thread at the tip of the shaft is screwed into the female thread of the nut 201. As a result, the overlapping flat plate portion 33, the race portion 80, and the flange portion 52b are sandwiched between the head of the bolt 200 and the nut 201. Consequently, the rotor 30, the race portion 80, and the bearing 50 are integrated into a single unit.

[0083] Second through-holes are formed in the flat plate portion 33, the race portion 80, the flange portion 52b, and the disc portion 12, extending axially through them. Multiple second through-holes are formed in a circumferential direction (for example, at equal intervals in the circumferential direction) at positions offset from the formation positions of the first through-holes. A bolt 210 is inserted through each second through-hole. The bolt 210 is inserted into the second through-hole with its head facing inward in the vehicle width direction and its shaft facing outward in the vehicle width direction. In this inserted state, the male thread of the bolt 210 is screwed into the female thread of the nut 211. As a result, the overlapping flat plate portion 33, the flange portion 52b, the race portion 80, and the disc portion 12 are sandwiched between the head of the bolt 210 and the nut 211. Consequently, the rotor 30, bearing 50, race portion 80, and wheel 10 are integrated into a single unit.

[0084] Next, the manufacturing method for the drive wheel will be explained. In this manufacturing method, after assembling the motor assembly equipped with the race section 80, the motor assembly is mounted onto the wheel 10.

[0085] With the flat surface of the race portion 80 in contact with the flat surface of the stepped portion 33b, the positioning portion 33c is fitted into the through hole 80b of the race portion 80. Then, while sandwiching the race portion 80 between the stepped portion 33b and the flange portion 52b, the bearing-side stepped portion 52c is fitted into the recess 33d.

[0086] With the flat plate portion 33, the race portion 80, and the flange portion 52b stacked together, the bolt 200 is inserted through each of the first through holes with its head facing outward from the rotor 30. Then, the female thread of the nut 201 is screwed onto the male thread of the bolt 200. As a result, the stacked flat plate portion 33, the race portion 80, and the flange portion 52b are sandwiched between the head of the bolt 200 and the nut 201. This creates a motor assembly in which the rotor 30, the race portion 80, and the bearing 50 are integrated. Here, since the flat surface of the race portion 80 is in contact with the flat surface of the stepped portion 33b, warping of the race portion 80 when the nut 201 is screwed onto the bolt 200 can be suppressed.

[0087] With the motor assembly and the disc portion 12 stacked together, insert the bolt 210 through each of the second through holes with the head of the bolt 210 facing the stator base portion 42. Then, screw the female thread of the nut 211 onto the male thread of the bolt 210. This integrates the motor assembly and the wheel 10.

[0088] According to the embodiment described above, it is possible to provide a drive wheel in which the coaxiality of the rotor 30, race section 80, and bearing 50 is reduced. This makes it possible to improve the detection accuracy of the detection unit 90.

[0089] <Sixth Embodiment> The sixth embodiment will now be described, focusing on the differences from the fifth embodiment, with reference to the drawings. In this embodiment, as shown in Figure 25, the race portion 80 is fixed to the rotor 30 instead of the inner ring 52. In Figure 25, components that are the same as or corresponding to those shown in Figure 24, etc., are denoted by the same reference numerals for convenience.

[0090] With the flat surface of the race portion 80 in contact with the flat surface of the stepped portion 33b, the positioning portion 33c is fitted into the through hole 80b of the race portion 80. In this state, the race portion 80 and the stepped portion 33b are fixed together by a bolt 220.

[0091] First through-holes are formed in the flat plate portion 33 and the flange portion 52b, penetrating in the axial direction. Multiple first through-holes are formed in a circumferential direction (for example, at equal intervals in the circumferential direction). A bolt 230 is inserted through each first through-hole. The bolt 230 is inserted into the first through-hole with its head facing inward in the vehicle width direction and its shaft facing outward in the vehicle width direction. In this inserted state, the male thread of the bolt 230 is screwed into the female thread of the nut 231. As a result, the overlapping flat plate portion 33 and flange portion 52b are sandwiched between the head of the bolt 230 and the nut 231. Consequently, the rotor 30, the race portion 80, and the bearing 50 are integrated into one unit.

[0092] Second through-holes are formed in the flat plate portion 33, flange portion 52b, and disc portion 12, extending axially. Multiple second through-holes are formed circumferentially (for example, at equal intervals circumferentially) at positions offset radially from the formation position of the first through-holes. A bolt 240 is inserted through each second through-hole. The bolt 240 is inserted into the second through-hole with its head facing inward in the vehicle width direction and its shaft facing outward in the vehicle width direction. In this inserted state, the male thread of the bolt 240 is screwed into the female thread of the nut 241. As a result, the overlapping flat plate portion 33, flange portion 52b, and disc portion 12 are sandwiched between the head of the bolt 240 and the nut 241. Consequently, the rotor 30 and the wheel 10 are integrated.

[0093] <Other Embodiments> Furthermore, each of the above embodiments may be implemented with the following modifications.

[0094] In the fourth embodiment, the circumferential centers of the first and second receiving coils 110 and 120 may be positioned downward with respect to the horizontal axis HL.

[0095] A non-metallic part, such as synthetic resin, may be provided in the notch 82 in Figure 2 or the opening 84 in Figure 17. In this case, a configuration in which metal and non-metallic parts are alternately provided in the circumferential direction can be realized in the race portion, and the rotation angle can be detected in the same manner as in the first embodiment.

[0096] The in-wheel motor 20 shown in Figure 1 does not necessarily have a race section 80. In this case, for example, in the flat plate section 33 of the in-wheel motor 20, shielding sections and openings may be alternately formed in the circumferential direction in the portion facing the coil section 92 in the axial direction, or recesses and protrusions may be alternately formed in the circumferential direction. In this case, the flat plate section 33 corresponds to the "detection rotating section".

[0097] The receiving coil formed on the substrate 91 may be either the first receiving coil 110 or the second receiving coil 120.

[0098] The sensor used to detect displacement is not limited to eddy current sensors; for example, a sensor that detects displacement using laser light may also be used.

[0099] 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".

[0100] The motor is not limited to those housed in the wheels; for example, it may be an onboard motor mounted on the vehicle body. Furthermore, the motor is not limited to an outer rotor type; it may be an inner rotor type.

[0101] 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. [Explanation of Symbols]

[0102] 20...In-wheel motor, 30...Rotor, 40...Stator, 50...Bearing, 80...Race section, 90...Detection unit.

Claims

1. A base portion (42) fixed to the vehicle body, The bearing (50) comprises an outer ring member (51), an inner ring member (52), and rolling elements (53) provided between the outer ring member and the inner ring member, and rotatably supports the wheel of the vehicle relative to the base portion. Of the outer ring member and the inner ring member, the first bearing member (52) is fixed to the wheel, and the other, the second bearing member (51), is fixed to the base portion. A disc-shaped detection rotating part (80, 83, 86) is provided to rotate integrally with the first bearing member and extends radially outward from the bearing relative to the first bearing member, Among the base portion, a displacement detection unit (90, 90A, 90B) is provided in a non-contact state with the detection rotating unit at a position away from the bearing in the radial direction and facing the detection rotating unit in the axial direction of the bearing, and outputs a signal corresponding to the axial displacement of the detection rotating unit. Equipped with, Of the aforementioned rotating detection part, at a position in the radial direction away from the bearing, annular detection target parts (81, 82, 84, 85, 87, 88) extending in the circumferential direction of the bearing are formed. The displacement detection unit is It has a planar receiving coil (110, 120) that is fixed to the base portion and positioned opposite the detection target portion in the axial direction, and extends in a direction intersecting the axial direction, A processing unit (70) that calculates the axial displacement of the detection rotating part based on the output voltage signal of the receiving coil, The displacement detection unit includes a first displacement detection unit (90A) and a second displacement detection unit (90B), Equipped with, The receiving coil of the first displacement detection unit is provided at a position facing the upper end of the detection rotating unit in the axial direction, The receiving coil of the second displacement detection unit is provided at a position facing the lower end of the detection rotating unit in the axial direction, The first displacement detection unit and the second displacement detection unit are configured such that the phase of the output voltage signal of the receiving coil provided by the first displacement detection unit and the phase of the output voltage signal of the receiving coil provided by the second displacement detection unit are the same. The processing unit calculates the displacement based on the difference between the output voltage signal of the receiving coil provided by the first displacement detection unit and the output voltage signal of the receiving coil provided by the second displacement detection unit, in a vehicle detection device.

2. The displacement detection unit comprises an excitation coil (100) to which an AC excitation voltage is supplied, The vehicle detection device according to claim 1, wherein the receiving coil induces a voltage when the excitation voltage is supplied to the excitation coil.

3. The detection target unit is, A configuration in which metal parts (81) and parts (82) that penetrate in the axial direction are alternately provided in the circumferential direction. A configuration in which recesses (88) that are recessed in the axial direction and protrusions (87) that project in the axial direction relative to the recesses are alternately provided in the circumferential direction, or A configuration in which metal parts and non-metal parts are alternately provided in the circumferential direction. It has become so The vehicle detection device according to claim 2, wherein the processing unit further calculates the rotation angle of the detection rotating unit based on the output voltage signal of the receiving coil.

4. The receiving coil is A first receiving coil (110) from which a voltage is induced when the excitation voltage is supplied to the excitation coil, The system includes a second receiving coil (120) which, when the excitation voltage is supplied to the excitation coil, induces a voltage that is out of phase with respect to the induced voltage of the first receiving coil, The vehicle detection device according to claim 3, wherein the processing unit calculates the rotation angle based on the output voltage signals of the first receiving coil and the second receiving coil.

5. The device comprises an amplification unit (AP) that amplifies and outputs the difference between the output voltage signal of the receiving coil provided by the first displacement detection unit and the output voltage signal of the receiving coil provided by the second displacement detection unit, The vehicle detection device according to any one of claims 1 to 4, wherein the processing unit calculates the displacement based on the output voltage signal of the amplification unit.

6. The vehicle detection device according to any one of claims 1 to 5, wherein the processing unit calculates the lateral force acting on the wheel based on the calculated displacement.

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