Detection device and module provided with detection device

Abstract

This detection device applied to a mechanical device (10, 200, 300) is provided with a target member (80, 180, 280, 380) and a displacement detection unit (90, 290, 390). The target member is provided, in relation to a flange part (62, 262, 344, 462) of a bearing member (40, 240, 340, 440), in an arrangement space that is adjacent to a second end part side of a cylindrical part (61, 461) of the bearing member in the axial direction and that is a space on the outside of the cylindrical part in the radial direction. The displacement detection unit is provided at a position facing the target member in the axial direction in the arrangement space.

Description

Detection device, module including detection device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-144386 filed on September 6, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a detection device and a module comprising the detection device.

[0003] A conventional mechanical device includes a bearing that rotatably supports a rotor relative to a base. The mechanical device includes an annular displacement detection part and a sensor device that detects radial and axial displacements of the displacement detection part. An example of a mechanical device with a sensor device is described in Patent Document 1.

[0004] Japanese Patent Application Laid-Open No. 2008-275508

[0005] Depending on the arrangement of the sensor device around the bearing, it may not be possible to effectively utilize the dead space around the bearing.

[0006] A primary object of the present disclosure is to provide a detection device and module that can effectively utilize dead space around a bearing.

[0007] The present disclosure relates to a detection device that is applied to a mechanical device, the mechanical device comprising: a rotating body; and a bearing member that rotatably supports the rotating body relative to a base portion; the bearing member has a cylindrical portion extending in an axial direction of the bearing member, and a flange portion that extends radially of the bearing member from a first end of the cylindrical portion in the axial direction and to which the rotating body is fixed, rotatably supporting the cylindrical portion and the flange portion relative to the base portion; the flange portion extends radially outward beyond the cylindrical portion in the radial direction; a target member provided in an arrangement space that is adjacent to a second end of the cylindrical portion in the axial direction with respect to the flange portion and is a space outer than the cylindrical portion in the radial direction; and a displacement detection unit provided in the arrangement space at a position facing the target member in the axial direction; the target member has an annular shape extending in a circumferential direction of the bearing member with the center of rotation of the bearing member as its center; one of the target member and the displacement detection unit is fixed to the flange portion and the other is fixed to the base portion; The displacement detection unit outputs a voltage signal corresponding to the relative displacement of the target member with respect to the displacement detection unit.

[0008] The arrangement space is a space adjacent to the flange portion in the axial direction on the side of the second end of the cylindrical portion and radially outward from the cylindrical portion. In the present disclosure, the arrangement space can be effectively used as a space for providing a target member and a displacement detection unit that outputs a voltage signal corresponding to the relative displacement of the target member.

[0009] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a perspective view of a wheel unit according to a first embodiment, Fig. 2 is a longitudinal cross-sectional view of the wheel unit, Fig. 3 is a partially enlarged view of the vicinity of the hub bearing of the wheel unit, Fig. 4 is a plan view of a target member, Fig. 5 is a perspective view of a sensor-equipped bearing module, Fig. 6 is a perspective view of the sensor-equipped bearing module, Fig. 7 is an exploded perspective view of the sensor-equipped bearing module, Fig. 8 is an exploded perspective view of the sensor-equipped bearing module, and Fig. 9 is a perspective view showing an attachment manner of a ring member. 10 is a plan view of the detection unit, FIG. 11 is a diagram showing the electrical configuration of the detection unit and the processing unit, FIG. 12 is a diagram showing a state in which the inner wheel is tilted relative to the outer wheel when a lateral force is applied to the tire, FIG. 13 is a diagram showing the vertical displacement of the inner wheel when a vertical load is applied to the tire, FIG. 14 is a projection view of the excitation coil and the first and second receiving coils in a plan view of the multilayer board, FIG. 15 is a diagram showing wiring patterns and vias formed on the first layer of the multilayer board, and FIG. 16 is a diagram showing wiring patterns and vias formed on the second layer of the multilayer board. 17 is a diagram showing a wiring pattern and vias formed on the third layer of a multilayer board, FIG. 18 is a diagram showing a wiring pattern and vias formed on the fourth layer of a multilayer board, FIG. 19 is a diagram showing the relative positional relationship between the first and second receiving coils and the shielding part, FIG. 20 is a diagram for explaining the principle of detecting displacement and rotation angle, FIG. 21 is a diagram for explaining the principle of detecting displacement and rotation angle, FIG. 22 is a simplified plan view of the second receiving coil, and FIG. 23 is a diagram showing the output voltage signal of the receiving coil and the signal 25 is a characteristic diagram showing the relationship between the displacement signal and the axial displacement; FIG. 26 is a diagram showing the change in the envelope from the reference state when a lateral force is applied; FIG. 27 is a diagram showing the relative positional relationship between the first and second receiving coils and the convex portion when a vertical load is applied; FIG. 28 is a diagram showing the change in the envelope from the reference state when a vertical load is applied; FIG. 29 is a characteristic diagram showing the relationship between the displacement signal and the vertical displacement;31 is a flowchart showing the procedure for calculating the load and rotational speed; FIG. 32 is a partially enlarged view of the vicinity of the hub bearing of a wheel unit according to a second embodiment; FIG. 33 is an exploded perspective view of a bearing module with a sensor according to a third embodiment; FIG. 34 is a perspective view of the bearing module with a sensor; FIG. 35 is a longitudinal cross-sectional view of a wheel unit according to a fourth embodiment; FIG. 36 is a longitudinal cross-sectional view of a wheel unit according to a fifth embodiment; FIG. 37 is a longitudinal cross-sectional view of a wheel unit according to another embodiment; FIG. 38 is a plan view of a target member according to another embodiment; and FIG. 39 is a partially enlarged view of the vicinity of the hub bearing of a wheel unit according to another embodiment.

[0010] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0011] First Embodiment A first embodiment of a detection device according to the present disclosure will be described below with reference to the drawings. The detection device of this embodiment is configured to be capable of calculating a force acting on a wheel (drive wheel or driven wheel) as a rotating body. The vehicle equipped with wheels is, for example, a four-wheeled passenger vehicle (for example, private or commercial use) having two front wheels and two rear wheels. However, the vehicle is not limited to this, and may be a vehicle other than a four-wheeled vehicle, such as a two-wheeled vehicle. Furthermore, the use of the vehicle is not limited to passenger use.

[0012] The wheel unit 10 as a mechanical device will be described using Figures 1 to 3. Figure 1 is a perspective cross-sectional view of the wheel unit 10, with the wheel unit 10 partially cut away, and Figure 2 is a cross-sectional view of the wheel unit 10 cut along a plane that passes through the center of rotation of the wheel unit 10 and extends vertically. Figure 3 is a partially enlarged view of Figure 2.

[0013] The wheel unit 10 includes a wheel 11 and a tire 14. The wheel 11 includes a cylindrical rim portion 12 and a disc portion 13 provided at the outer end of the rim portion 12 in the vehicle width direction. The disc portion 13 includes a disc attachment portion 18 located in the center of the disc portion 13 and spoke portions 19 extending radially from the disc attachment portion 18 to the rim portion 12. The tire 14 is attached to the outer periphery of the rim portion 12.

[0014] The wheel unit 10 includes a brake device 20 and a hub bearing 40 (corresponding to a "bearing member"). The brake device 20 is a disc-type friction braking device, and includes a disc rotor 21 that is circular as a whole, and a brake caliper 33. The brake caliper 33 is actuated by hydraulic pressure, an electric signal, or the like, and includes a pair of disc pads that contact the disc rotor 21 to generate braking force, a piston that presses the disc pads against the disc rotor 21, and a caliper body that supports the brake pads and the piston.

[0015] In the following, the direction in which the rotational axis of the hub bearing 40 extends is referred to as the axial direction, the direction extending radially from the rotational axis is referred to as the radial direction, and the direction extending circumferentially around the rotational axis is referred to as the circumferential direction.

[0016] The disc rotor 21 of this embodiment is a ventilated disc having an internal cavity for ventilation. The disc rotor 21 has a hat portion 22 and a sliding portion 23. The hat portion 22 is attached to the hub bearing 40. The hat portion 22 has a disk-shaped bottom surface portion 24 and a disc peripheral wall portion 25. A mounting hole 26 is formed in the center of the bottom surface portion 24. Through holes 27 are formed around the mounting hole 26 and arranged in the circumferential direction. The disc rotor 21 is connected to the hub bearing 40 using the mounting holes 26 and the through holes 27. The disc peripheral wall portion 25 is cylindrical and extends from the outer periphery of the bottom surface portion 24, forming the peripheral surface of the hat portion 22.

[0017] A sliding portion 23 is connected to the end of the disk peripheral wall portion 25 opposite the bottom surface portion 24. The sliding portion 23 is formed to protrude outward in an annular shape from the disk peripheral wall portion 25. The front and back surfaces of the sliding portion 23 form a pair of sliding surfaces that are pressed against the disk pad.

[0018] The sliding portion 23 includes an inner disk portion 28, an outer disk portion 29 disposed on the outer side of the inner disk portion 28, and fins 30. The fins 30 connect the inner disk portion 28 and the outer disk portion 29 at multiple locations in the circumferential direction. The fins 30 extend radially, and the space surrounded by the inner disk portion 28, the outer disk portion 29, and the fins 30 forms an air passage penetrating in the radial direction (diameter). The air passage extends from an air intake port 31 formed on the radially inner side of the sliding portion 23 to an air exhaust port 32 formed on the radially outer side.

[0019] The hub bearing 40 is a rolling bearing (specifically, a radial ball bearing) and includes an outer ring 50 (corresponding to the "second bearing portion"), an inner ring 60 (corresponding to the "first bearing portion"), and a plurality of rolling elements 41 (specifically, balls) arranged between the outer ring 50 and the inner ring 60. The hub bearing 40 may also be a radial roller bearing that includes rollers as the rolling elements 41.

[0020] The inner ring 60 includes an inner cylindrical portion 61 (corresponding to a "first cylindrical portion") extending in the axial direction, and a flange portion 62 extending radially from a first end of the inner cylindrical portion 61 in the axial direction. A through hole 62 is formed in the inner cylindrical portion 61, penetrating the inner cylindrical portion 61 in the axial direction. A spline is formed on the inner peripheral surface of the through hole 62. A shaft (not shown) is fitted into the through hole 62 to transmit rotational power from a driving power source such as a motor.

[0021] The outer ring 50 has an outer cylindrical portion 51 (corresponding to a "second cylindrical portion") provided at a position facing radially outward from the inner cylindrical portion 61. The rolling elements 41 are provided between the outer cylindrical portion 51 and the inner cylindrical portion 61. The outer ring 50 has a hub mounting portion 52 that protrudes radially outward from the outer cylindrical portion 51. The hub mounting portion 52 is fixed with bolts 16 to a knuckle 15 serving as a base portion.

[0022] The flange portion 62 is disk-shaped and extends radially outward beyond the outer cylindrical portion 51. The flange portion 62 has through holes 63 arranged in the circumferential direction, through which the hub bolts 17 for fixing the wheel 11 are inserted.

[0023] The wheel unit 10 includes a heat shield 35. The heat shield 35 is provided on the inner side in the vehicle width direction of the hub bearing 40 and the sliding portion 23 of the disc rotor 21. The heat shield 35 extends radially outward beyond the outer peripheral edge of the sliding portion 23.

[0024] The wheel unit 10 includes a detection device. The detection device is provided in the inner space of the wheel 11 and includes a target member 80 and a detection unit 90 (corresponding to a "displacement detection unit"). The detection device detects the rotational speed of the wheel consisting of the wheel 11 and the tire 14, the lateral force Fy acting between the ground contact surface (ground) GL and the wheel (specifically, the tire 14), and the force acting between the ground contact surface GL and the wheel in a direction perpendicular to the ground contact surface GL (hereinafter referred to as a vertical load Fz). The direction in which the lateral force acts is perpendicular to the direction in which the vertical load acts. For example, the calculated rotational speed, lateral force, and vertical load are used in a control device (specifically, an ECU: Electronic Control Unit) provided in the vehicle to control the vehicle's travel, which is a moving object. The structure of the detection device will be described below with reference to Figures 1 to 6.

[0025] The target member 80 is made of a metal material (e.g., aluminum or iron). The target member 80 includes a detection rotor 81 and an inner peripheral wall 82. The detection rotor 81 is provided axially opposite the detection unit 90 without contacting the detection unit 90, and has an annular shape extending circumferentially about the central axis of rotation of the hub bearing 40. The inner peripheral wall 82 extends axially from the outer peripheral edge of the detection rotor 81 toward the flange 62. A through-hole 83 is formed in the center of the detection rotor 81, penetrating it in the axial direction. The tip of the inner cylindrical portion 61 is inserted into the through-hole 83.

[0026] The detection rotating portion 81 has protrusions 84 arranged in a circumferential direction, protruding axially (inward in the vehicle width direction) from a flat surface of the detection rotating portion 81. The flat surfaces between the circumferentially arranged protrusions 84 form recesses 85. The protrusions 84 and recesses 85 are arranged alternately in the circumferential direction. In this embodiment, 12 pairs of protrusions 84 and recesses 85 are provided.

[0027] 4, LCi indicates the center axis of the inner ring 60. In this embodiment, the angle α1 formed by the axis passing through the center axis LCi and one circumferential end of the convex portion 84 and the axis passing through the center axis LCi and the other circumferential end of the convex portion 84 is equal to the angle α2 formed by the axis passing through the center axis LCi and one circumferential end of the concave portion 85 and the axis passing through the center axis LCi and the other circumferential end of the concave portion 85. Therefore, the circumferential length of the multiple convex portions 84 and the circumferential length of the multiple concave portions 85 are equal to each other.

[0028] The detection device includes a ring member 86 as a fixing member for fixing the target member 80 to the flange portion 62. The ring member 86 includes a disk portion 87 and an outer peripheral wall portion 88. A through-hole 87a that passes through in the axial direction is formed in the center of the disk portion 87. The tip end of the inner cylindrical portion 61 is inserted into the through-hole 87a.

[0029] A mounting surface 62a, which is a flat, annular surface extending in the circumferential direction, is formed on a portion of the flange portion 62 opposite the detection unit 90 in the axial direction. A first annular surface 87b of the disc portion 87 abuts (specifically, makes surface contact with) the mounting surface 62a of the flange portion 62. A first surface 24a of the bottom surface portion 24 constituting the disc rotor 21 abuts (specifically, makes surface contact with) a second surface 87c, which is the back surface of the first surface 87b, of the disc portion 87. A mounting surface 18a, which is a flat surface of the disc mounting portion 18, is in surface contact with a second surface 24b, which is the back surface of the first surface 24a of the bottom surface portion 24.

[0030] In the disk portion 87 that constitutes the ring member 86, through holes 87d that penetrate in the axial direction are formed in a row in the circumferential direction around the through hole 87a. With the bottom surface portion 24, disk portion 87, and flange portion 62 overlapping the disk mounting portion 18, hub bolts 17 are inserted into the through holes 63, 87d, and 27. Nuts 34 are threaded onto the hub bolts 17, thereby fixing the disk rotor 21, ring member 86, and hub bearing 40 to the disk mounting portion 18. As a result, the target member 80, disk rotor 21, and inner ring 60 are coaxial, and the target member 80, disk rotor 21, and wheel 11 rotate together.

[0031] The outer peripheral wall portion 88 is cylindrical and extends axially from the outer peripheral edge of the disk portion 87 toward the detection unit 90. The outer peripheral surface of the inner peripheral wall portion 82 is pressed against the inner peripheral surface of the outer peripheral wall portion 88, thereby fixing the target member 80 to the flange portion 62. The outer peripheral wall portion 88 does not protrude from the flange portion 62 when viewed from the front of the mounting surface 62a.

[0032] The outer peripheral wall portion 88 extends in the axial direction to a position where it covers the radial outside of the detection unit 90. This makes it possible to protect the detection unit 90 from heat generated by the brake device 20 (e.g., the disc rotor 21) and foreign matter.

[0033] The target member 80 is provided radially inward of the disc peripheral wall portion 25 that constitutes the disc rotor 21. This allows the disc rotor 21 to protect against foreign matter from the outside. The detection unit 90 is also provided at a position circumferentially separated from the brake caliper 33.

[0034] The target member 80 is provided at a position radially opposite the air intake 31 of the disk rotor 21. This allows the target member 80 and the detection unit 90 housed in the ring member 86 to be cooled by using the wind guided through the air intake 31.

[0035] The inner peripheral wall portion 82 abuts against the outer peripheral edge portion of the flange portion 62 from the outside in the radial direction. In addition, the tip portion of the inner peripheral wall portion 82 abuts against the first surface 87b of the disk portion 87.

[0036] 3, a step 88a is formed at the base end of the outer peripheral wall portion 88. The step 88a projects radially inward and is used to press-fit and fix the tip end of the inner peripheral wall portion 82. The step 88a is formed, for example, over the entire circumferential direction.

[0037] In this embodiment, the material of the inner peripheral wall portion 82 is the same as the material of the outer peripheral wall portion 88 (for example, aluminum). In this case, the linear expansion coefficients of the peripheral wall portions 82, 88 are the same, which prevents the peripheral wall portions 82, 88 from being damaged by thermal stress in high-temperature and low-temperature environments, and prevents the ring member 86 from coming off the target member 80 due to loosening of the press-fit.

[0038] In this embodiment, the target member 80 is divided into two parts in the circumferential direction, as shown in Figure 4, more specifically, the two parts are divided into two parts with equal circumferential lengths. The reason for dividing the target member 80 is to facilitate the assembly of the target member 80 to the hub bearing 40. For example, the target member 80 can be attached to a completed hub bearing 40 later. Hereinafter, one of the divided parts of the target member 80 will be referred to as a first divided part 80A, and the other part will be referred to as a second divided part 80B.

[0039] 4, in this embodiment, the convex portion 84 is not formed across the boundary surface between the first and second divided members 80A and 80B. This makes it difficult for steps to occur on the surface of the convex portion 84, thereby improving the detection accuracy of displacement and the like by the detection unit 90. However, the convex portion 84 may be formed across the boundary surface.

[0040] The detection unit 90 is a so-called eddy current inductive sensor, and includes a substrate 91, a coil portion 92 provided on the substrate 91, and a circuit portion 93, as shown in FIG.

[0041] 3 and 6 , the substrate 91 is provided with its plate surface extending in the vertical direction. The substrate 91 is provided in an arrangement space that is adjacent to the flange portion 62 on the inner side in the vehicle width direction and that is radially outward of the inner cylindrical portion 61 and the outer cylindrical portion 51. In the arrangement space, the target member 80 is provided at a position axially opposite the substrate 91. In this embodiment, the substrate 91 is provided at a position axially opposite the upper end of the target member 80.

[0042] The board 91 is provided between the flange portion 62 and the hub mounting portion 52. This allows for effective use of the space inside the flange portion 62 in the vehicle width direction. The outer cylindrical portion 51 has board mounting portions 53 protruding in the radial direction provided between the hub mounting portions 52 lined up in the circumferential direction. The board mounting portions 53 are provided in positions that do not overlap with the hub mounting portions 52 in the circumferential direction.

[0043] The substrate 91 has an arc shape that follows the detection rotating portion 81. Through holes 91 a are formed in both circumferential ends of the substrate 91. Female threaded holes 53 a are formed in the substrate mounting portion 53. With a bolt 99 inserted into the through hole 91 a, the male thread of the bolt 99 is screwed into the female threaded hole 53 a, thereby fixing both circumferential ends of the substrate 91 to the substrate mounting portion 53.

[0044] A method for manufacturing a sensor-equipped bearing module including a hub bearing 40, a target member 80, a detection unit 90, and a ring member 86 will now be described.

[0045] 7 and 8 , board 91 is fixed to board mounting portion 53 with bolts 99. The portion of outer cylindrical portion 51 closer to flange portion 62 than hub mounting portion 52 is sandwiched between first and second divided members 80A and 80B, and the tip ends of inner peripheral wall portions 82 of first and second divided members 80A and 80B are brought into contact with the outer periphery of flange portion 62.

[0046] 9 , with the hub bolt 17 inserted through the through-hole 87d of the disc portion 87 and the tip of the inner cylindrical portion 61 inserted through the through-hole 87a in the center of the disc portion 87, the ring member 86 is pressed into the hub bearing 40 until the tip of the inner circumferential wall portion 82 abuts against the first surface 87b of the disc portion 87. In this case, the ring member 86 is press-fitted and fixed into the target member 80 by the stepped portion 88a of the outer circumferential wall portion 88. As a result, the hub bearing 40 and the target member 80 are integrated together.

[0047] The mounting surface 62a of the flange portion 62 is a portion necessary for mounting the wheel 11, and has a relatively high degree of flatness. Because the ring member 86 is assembled using this mounting surface 62a, it is possible to minimize structural changes to the hub bearing 40 required to mount the detection device, while improving the detection accuracy of the detection device.

[0048] Next, the electrical configuration of the detection unit 90 will be described with reference to FIGS.

[0049] In the detection unit 90, the coil section 92 includes an excitation coil 100 and a receiving coil. In this embodiment, the receiving coils are a first receiving coil 110 and a second receiving coil 120. Each of the coils 100, 110, and 120 is a planar coil. The substrate 91 is a multi-layer substrate. Each of the coils 100, 110, and 120 is formed by wiring patterns, vias, and the like formed on each layer of the substrate 91. Because each of the coils 100, 110, and 120 is a planar coil, it is easy to arrange each of the coils 100, 110, and 120 even if it is not possible to secure a large axial space inside the wheel 11.

[0050] The circuit unit 93 is configured as an integrated circuit. As shown in Fig. 11, the circuit unit 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 having the same or equivalent frequency as the excitation voltage is induced in each of the coils 110, 120. The receiving circuit 95 detects output voltage signals across both ends of each of the coils 110, 120.

[0051] 11 , the circuit unit 93 is provided with a connector 96 electrically connected to an excitation circuit 94 and a receiving circuit 95. The connector 96 is electrically connected to the processing unit 70 via a cable 97. The circuit unit 93 and the processing unit 70 exchange signals via the cable 97.

[0052] 6, the connector 96 is provided at a position that does not overlap the hub mounting portion 52 and the board mounting portion 53 in the circumferential direction. This prevents the connector 96 and the cable 97 from interfering with the hub mounting portion 52 and the board mounting portion 53.

[0053] 1, an insertion hole 35a is formed in the heat shield 35, and the processing unit 70 and the circuit unit 93 are electrically connected via a cable 97 inserted through the insertion hole 35a. The insertion hole 35a is formed in a position on the heat shield 35 that faces the connector 96 in the axial direction. This makes it easy to route the cable 97 in the wheel unit 10. The processing unit 70 may be provided on the vehicle body or may be built into the wheel unit 10.

[0054] The processing unit 70 includes a CPU (Central Processing Unit). The functions of the processing unit 70 can be provided by software stored in a physical memory device and a computer executing the software, software alone, hardware alone, or a combination thereof. For example, if the microcomputer of the processing unit 70 is implemented as a hardware electronic circuit, it can be implemented by a digital circuit including multiple logic circuits or an analog circuit. For example, the microcomputer executes a program stored in a non-transitory tangible storage medium serving as its own storage unit. The program includes, for example, a program for the process shown in FIG. 31 (described later). A set of instructions constituting the program is executed to perform a method corresponding to the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, via OTA (Over the Air).

[0055] When a lateral force Fy acts on the wheel as shown in Fig. 2, the inclination θ of the center axis LCi of the inner ring 60 relative to the center axis LCo of the outer ring 50 increases, as shown in Fig. 12. In this case, the axial distance between each of the coils 110, 120 and the detection rotating portion 81 of the target member 80 changes, causing a change in the amplitude of the output voltage signals of each of the coils 110, 120. The processing unit 70 calculates the axial displacement ΔY of the target member 80 based on this change in amplitude, and then calculates the lateral force Fy based on the calculated axial displacement ΔY.

[0056] On the other hand, when a vertical load Fz acts on the wheel, the central axis LCi of the inner ring 60 is displaced in a direction perpendicular to the central axis LCo of the outer ring 50, as shown in Fig. 13. As a result, the target member 80 fixed to the flange portion 62 is also displaced. In this case, the detection unit 90 is configured so that the amplitude of the output voltage signals of the first receiving coil 110 and the second receiving coil 120 changes. This configuration will be described in detail later. Based on this change in amplitude, the processing unit 70 calculates the displacement of the target member 80 in a direction perpendicular to the axial direction and the vehicle length direction (hereinafter referred to as the vertical displacement ΔZ), and calculates the vertical load Fz based on the calculated vertical displacement ΔZ.

[0057] 14, the first receiving coil 110 and the second receiving coil 120 are provided in an area surrounded by the exciting coil 100 in a plan view of the substrate 91. The exciting coil 100 is a planar coil having a plurality of turns, and has an arc shape extending in the circumferential direction of the outer ring.

[0058] Next, the coil unit 92 will be described with reference to Figures 14 to 19. In this embodiment, the substrate 91 is a multi-layer substrate (specifically, a four-layer substrate), and the excitation coil 100 and each of the receiving coils 110 and 120 that make up the coil unit 92 are configured by wiring patterns on the multi-layer substrate. An example of the configuration of the coil unit 92 will be described below.

[0059] 15 to 18 show the wiring patterns formed on each layer in a plan view of the surface of the substrate 91. Fig. 14(a) is a diagram in which the wiring patterns of the second to fourth layers are projected onto the wiring pattern of the first layer.

[0060] First, the excitation coil 100 will be described. As shown in FIGS. 15 and 16 , the excitation coil 100 is formed on the first and second layers adjacent to each other in the thickness direction of the substrate 91. The wiring patterns on each layer are electrically connected by conductors filled in the excitation-side vias VI. The first layer includes, as wiring patterns, a first excitation end 101 electrically connected to the excitation circuit 94 and a first excitation pattern 102 formed by winding multiple times (three times) clockwise from the first excitation end 101 to the excitation-side vias VI. The second layer includes, as wiring patterns, a second excitation end 103 electrically connected to the excitation circuit 94 and a second excitation pattern 104 formed by winding multiple times (three times) counterclockwise from the second excitation end 103 to the excitation-side vias VI. As a result, the excitation coil 100, a six-turn planar coil, is formed on the substrate 91. The excitation coil 100 has an arc shape extending in the circumferential direction of the outer ring 50 .

[0061] Next, the first receiving coil 110 will be described. As shown in FIGS. 15 to 18, the first receiving coil 110 is formed on the first to fourth layers. As shown in FIG. 17, a first receiving end portion 111 electrically connected to the receiving circuit 95 is formed on the third layer. A first end of a pattern 112 on the first layer is connected to the first receiving end portion 111 via a first A via VA1. A first end of a pattern 113 on the second layer is connected to a second end of the pattern 112 via a second A via VA2. A first end of a pattern 115 on the first layer is connected to a second end of the pattern 113 via a third A via VA3, a pattern 114, and a fourth A via VA4. A first end of a pattern 116 on the second layer is connected to a second end of the pattern 115 via a fifth A via VA5. A second receiving end 118 on the fourth layer is connected to a second end of the pattern 116 through a sixth A via VA6, a pattern 117, and a 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 a first output voltage signal v1.

[0062] As shown in FIG. 14( a), the first receiving coil 110 is provided in a 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 is composed of a first portion that generates a voltage of a first polarity between the first receiving end 111 and the second receiving end 118 of the first receiving coil 110, and a second portion that generates a voltage of a second polarity opposite to the first polarity. More specifically, as shown in FIG. 14( b), in a plan view of the substrate 91, the circumferential center portion of the first receiving coil 110 is a first portion 110A of one turn, and both ends of the first portion 110A of the first receiving coil 110 are second portions 110B of the same number of turns (one turn) as the first portion 110A. As a result, the pattern shapes of the first and second parts 110A and 110B on one side of the circumferential central axis Lt of the first receiving coil 110 and the pattern shapes of the first and second parts 110A and 110B on the other side are symmetrical with respect to the central axis Lt.

[0063] Next, the second receiving coil 120 will be described. As shown in FIGS. 15 to 18, the second receiving coil 120 is formed on the first to fourth layers. As shown in FIG. 17, a third receiving end portion 121 electrically connected to the receiving circuit 95 is formed on the third layer. A first end of a pattern 122 on the second layer is connected to the third receiving end portion 121 via a first B via VB1. A first end of a pattern 123 on the first layer is connected to a second end of the pattern 122 via a second B via VB2. A first end of a pattern 125 on the first layer is connected to a second end of the pattern 123 via a third A via VA3, a pattern 124, and a fourth B via VB4. A first end of a pattern 126 on the second layer is connected to a second end of the pattern 125 via a fifth B via VB5. A fourth receiving end 128 on the fourth layer is connected to the second end of the pattern 126 through a sixth B via VB6, a pattern 127, and a seventh 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 a second output voltage signal v2.

[0064] 14A, the second receiver coil 120 is provided in an area surrounded by the excitation coil 100 in a plan view of the substrate 91. The circumferential length of the second receiver coil 120 is the same as the circumferential length of the first receiver coil 110. The radial length of the second receiver coil 120 is greater than the radial length of the first receiver coil 110.

[0065] 14(c), the second receiving coil 120 is composed of a first portion 120A and a second portion 120B, similar to the first receiving coil 110. In a plan view of the substrate 91, one side of the circumferential central axis Lt of the second receiving coil 120 is the first portion 120A, and the other side is the second portion 120B.

[0066] 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 of each of the convex portion 84 and the concave portion 85. In addition, as shown in FIG. 14A, in a plan view of the substrate 91, the positions of both ends of the second receiving coil 120 in the circumferential direction are the same as the positions of both ends of the first receiving coil 110 in the circumferential direction.

[0067] The substrate 91 is provided so that the central axis Lt in the circumferential direction of the first and second receiving coils 110 and 120 and the upper end of the detection rotating part 81 are opposed to each other in the axial direction.

[0068] In a plan view of the substrate 91, the radially outer end of the second receiving coil 120 is located on a first concentric circle C1 centered on the central axis LCo of the outer ring 50, as shown in FIG. 19 . The radially outer end of the first receiving coil 110 is located on a second concentric circle C2 centered on the central axis LCo. The radius of the second concentric circle C2 is smaller than the radius of the first concentric circle C1. The radially inner end of the first receiving coil 110 is located on a third concentric circle C3 centered on the central axis LCo. The radius of the third concentric circle C3 is smaller than the radius of the second concentric circle C2. The radially inner end of the second receiving coil 120 is located on a fourth concentric circle C4 centered on the central axis LCo. The radius of the fourth concentric circle C4 is smaller than the radius of the third concentric circle C3.

[0069] The radially outer end of the second receiving coil 120 protrudes from the radially outer end 84a of the protrusion 84 in the reference state. The reference state can be set arbitrarily. The reference state is, for example, a state in which the vehicle is stopped, and more specifically, a state in which the vehicle is stopped on a level road surface. CP shown in FIG. 19 is a concentric circle CP that is centered on the central axis LCo of the outer ring 50 and passes through the radially outer end 84a of the protrusion 84 in the reference state.

[0070] Next, the principle by which the detection unit 90 can detect displacement, rotation angle, and rotation speed will be described with reference to FIGS.

[0071] First, an overview of this principle will be explained using Figures 20 and 21. As shown in Figure 20, 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 interlinks with the receiving coil. A voltage ve(t) proportional to the time rate of change of the interlinkage magnetic flux is induced at both ends of the receiving coil.

[0072] Figure 21 shows a state in which a protrusion, which is a metal part, faces a part of the receiving coil. Eddy currents flow in the part of the protrusion facing the receiving coil due to the interlinkage magnetic flux caused by the energization of the excitation coil. These eddy currents generate magnetic flux in a direction that weakens the magnetic flux that generates an induced voltage in the receiving coil, thereby reducing the amplitude of the induced voltage in the receiving coil. In other words, the amplitude of the potential difference between both ends of the receiving coil is proportional to the area of ​​the receiving coil that does not face the protrusion.

[0073] 20 and 21 , the detection principle will be described using the second receiving coil 120 as an example with reference to Figures 22 and 23 . Figures 22 and 23 are diagrams illustrating the second receiving coil 120 and the convex portion 84 shown in Figure 14 etc., with the circumferential direction being linear. Figure 23 is a diagram illustrating the relative positional relationship between the second receiving coil 120 and the convex portion 84, and the transition of the second output voltage signal v2 of the second receiving coil 120.

[0074] 22 and 23, the direction (I+) in which current flows from the second receiving end 118 to the first receiving end 111 is referred to as the positive direction, and the direction (I-) in which current flows from the first receiving end 111 to the second receiving end 118 is referred to as the negative direction. In addition, in Figures 22 and 23, magnetic flux from the excitation coil 100 passes from the front side to the back side of the paper.

[0075] 23 , the central half of the first portion 120A and the central half of the second portion 120B face the convex portion 84. A voltage that causes a current to flow in the positive direction is induced in the first portion 120A, and a voltage that causes a current to flow in the negative direction is induced in the second portion 120B. As a result, the induced voltages generated in the first portion 120A and the second portion 120B cancel each other out, and the amplitude of the second output voltage signal v2 becomes zero.

[0076] At time t2, the second portion 120B of the first portion 120A and the second portion 120B faces the convex portion 84. In this case, a voltage that attempts to pass a current in the positive direction is induced in the first portion 120A, and the induced voltage in the second portion 120B becomes zero. 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 becomes larger as the target member 80 approaches the second receiving coil 120.

[0077] At time t3, the end half of the first portion 120A and the end half of the second portion 120B face the convex portion 84. A voltage that attempts to pass a current in the positive direction is induced in the first portion 120A, and a voltage that attempts to pass a current in the negative direction is induced in the second portion 120B. As a result, the induced voltages generated in the first portion 120A and the second portion 120B cancel each other out, and the amplitude of the second output voltage signal v2 becomes zero.

[0078] At time t4, the first portion 120A of the first portion 120A and the second portion 120B faces the convex portion 84. In this case, a voltage that attempts to pass a current in the negative direction is induced in the second portion 120B, and the induced voltage in the first portion 120A becomes zero. As a result, the amplitude of the second output voltage signal v2 becomes a maximum value on the second polarity (negative polarity) side, which is opposite to the first polarity. This maximum value becomes larger as the target member 80 approaches the second receiving coil 120.

[0079] In this embodiment, convex portions 84 and concave portions 85 are alternately formed on the target member 80. Therefore, while the wheel is rotating, the amplitude of the second output voltage signal v2 of the second receiving coil 120 changes periodically, and the envelope of the second output voltage signal v2 (hereinafter, the second envelope ENV2) becomes sinusoidal, as shown by the dashed lines in Figures 23 and 24.

[0080] In this embodiment, when an excitation voltage is supplied to the excitation coil 100, the phase difference between the first output voltage signal v1 of the first receiver coil 110 and the second output voltage signal v2 of the second receiver coil 120 is 90 degrees. Therefore, as shown by the dashed dotted line in Fig. 24, the phase difference between the envelope of the first output voltage signal v1 and the second envelope ENV2 (hereinafter referred to as the first envelope ENV1) is also 90 degrees.

[0081] 24, the amplitude of the second envelope ENV2 is smaller than the amplitude of the first envelope ENV1. This is because, as shown in FIG. 14(a), in a plan view of the substrate 91, the area surrounded by the second receiver coil 120 is larger than the area surrounded by the first receiver coil 110.

[0082] The receiving circuit 95 outputs the deviation amount of the actual amplitude of the first envelope curve ENV1 from the amplitude of the first envelope curve ES1 in the reference state as a first displacement signal to the processing unit 70. The receiving circuit 95 also outputs the deviation amount of the actual amplitude of the second envelope curve ENV2 from the amplitude of the second envelope curve ES2 in the reference state as a second displacement signal to the processing unit 70. In this embodiment, the receiving circuit 95 is configured so that the first and second displacement signals are 0 in the reference state. Each displacement signal is updated each time the maximum positive and negative amplitude values ​​of the output voltage signals v1 and v2 appear.

[0083] A case where the lateral force acting on the wheel changes will be described.

[0084] When the direction of the lateral force is toward the outside in the vehicle width direction, the upper end of the target member 80 is displaced toward the inside in the vehicle width direction, and the inner wheel 60 tilts relative to the outer wheel 50 so that the lower end of the target member 80 is displaced toward the outside in the vehicle width direction. In this case, the polarity of the axial displacement ΔY and each displacement signal is set to positive, as shown in FIG. 25 . The larger the axial displacement ΔY in the positive direction, the larger the positive direction each displacement signal becomes. This is because, as shown in FIG. 26( a), the closer the target member 80 is to the first and second receiving coils 110 and 120, the larger the actual first and second envelopes ENV1 and ENV2 become relative to the first and second envelopes ES1 and ES2 in the reference state.

[0085] When the direction of the lateral force is toward the inside of the vehicle width direction, the inner wheel 60 tilts relative to the outer wheel 50 so that the lower end of the target member 80 is displaced toward the inside of the vehicle width direction and the upper end of the target member 80 is displaced toward the outside of the vehicle width direction. In this case, the polarity of the axial displacement ΔY and each displacement signal is negative, as shown in FIG. 25 . The more negative the axial displacement ΔY, the more negative the displacement signals. This is because, as shown in FIG. 26( b), the further the target member 80 is from the first and second receiving coils 110 and 120, the smaller the actual first and second envelopes ENV1 and ENV2 become relative to the first and second envelopes ES1 and ES2 in the reference state. Meanwhile, the first and second displacement signals in the reference state are zero.

[0086] Next, a case where the vertical load acting on the wheel changes will be described.

[0087] Fig. 27 shows the relative positional relationship between the receiver coils 110, 120 and the convex portion 84 in the reference state. Fig. 27 is a diagram showing the first and second receiver coils 110, 120 and the convex portion 84 shown in Fig. 14 etc. as linear in the circumferential direction. In the figure, the hatched portions are the portions of the receiver coils 110, 120 that face the convex portion 84. Fig. 28(a) shows the transition of each envelope curve in the reference state.

[0088] When the upward vertical load increases, the upper end of the target member 80 is displaced upward. In this case, the polarity of the vertical displacement ΔZ and each displacement signal is set to positive, as shown in FIG. 29 . The more positive the vertical displacement ΔZ, the more positive the displacement signals. This is because, as shown in FIG. 27( b), the area of ​​the portion of the second receiving coil 120 facing the convex portion 84 increases as the target member 80 is displaced upward, and as shown in FIG. 28( b), the actual second envelope ENV2 becomes smaller than the second envelope ES2 in the reference state.

[0089] On the other hand, when the downward vertical load increases, the upper end of the target member 80 is displaced downward. In this case, the polarity of the vertical displacement ΔZ and each displacement signal is set to negative, as shown in FIG. 29 . The more negative the vertical displacement ΔZ, the more negative the displacement signals. This is because, as shown in FIG. 27( c), the area of ​​the portion of the second receiving coil 120 facing the convex portion 84 decreases as the target member 80 is displaced downward, and as shown in FIG. 28( c), the actual second envelope ENV2 becomes larger than the second envelope ES2 in the reference state.

[0090] 25, the second lateral force coefficient K2y, which is the amount of change in the second displacement signal per unit change in the axial displacement ΔY, is larger than the first lateral force coefficient K1y, which is the amount of change in the first change signal per unit change in the axial displacement ΔY. This is because, in a plan view of the substrate 91, the area surrounded by the second receiving coil 120 is larger than the area surrounded by the first receiving coil 110.

[0091] 29, the second vertical load coefficient K2z, which is the amount of change in the second displacement signal per unit change in the vertical displacement ΔZ, is larger than the first vertical load coefficient K1z, which is the amount of change in the first change signal per unit change in the vertical displacement ΔZ. This is because, in a plan view of the substrate 91, the area surrounded by the second receiving coil 120 is larger than the area surrounded by the first receiving coil 110.

[0092] Furthermore, the second vertical load coefficient K2z is smaller than the second lateral force coefficient K2y, and the first vertical load coefficient K1z is smaller than the first lateral force coefficient K1y. This is because, for example, the rigidity of the wheel in the vertical direction is greater than the rigidity in the vehicle width direction. In this embodiment, the relationship is "K2y > K1y > K2z > K1z." Incidentally, the detection unit 90 may be configured so that the slope of the first vertical load coefficient K1z in FIG. 29 is zero.

[0093] From the above, it is possible to uniquely link the combination of the axial displacement ΔY and the vertical displacement ΔZ with the combination of the first displacement signal and the second displacement signal. Therefore, the displacement calculation unit 71 constituting the processing unit 70 calculates the axial displacement ΔY and the vertical displacement ΔZ based on the first and second displacement signals and map information or mathematical formula information in which the first and second displacement signals, the axial displacement ΔY, and the vertical displacement ΔZ are correlated.

[0094] The force calculation unit 72 constituting the processing unit 70 calculates the lateral force Fy based on the calculated axial displacement ΔY and map information or formula information correlating the axial displacement ΔY and the lateral force Fy. The force calculation unit 72 calculates the vertical load Fz based on the calculated vertical displacement ΔZ and map information or formula information correlating the vertical displacement ΔZ and the vertical load Fz.

[0095] The map information or formula information may be stored in a storage unit (e.g., a nonvolatile memory) included in the processing unit 70. The force calculation unit 72 may calculate the lateral force Fy and the vertical load Fz based on map information or formula information that correlates the first and second displacement signals with the lateral force Fy and the vertical load Fz. Calculation of the load based on the first and second displacement signals and map information or formula information can be similarly applied to each of the following embodiments.

[0096] The rotation speed calculation unit 73 constituting the processing unit 70 calculates the rotation angle of the wheel based on at least one of the first output voltage signal v1 and the second output voltage signal v2.

[0097] Specifically, for example, the rotation speed calculation unit 73 may calculate the rotation angle based on the first envelope curve ENV1 or the second envelope curve ENV2. This calculation method is based on the fact that the envelope curve is information indicating the transition of the amplitude of the output voltage signal and that the amplitude of the output voltage signal depends on the rotation angle.

[0098] Furthermore, for example, the rotation speed calculation unit 73 may calculate the rotation angle by using synchronous detection and a low-pass filter with the first output voltage signal v1, the second output voltage signal v2, and the excitation voltage vr as inputs. This calculation method is a digital tracking method, and is described, for example, in paragraphs 0028 to 0030 of the specification of JP 2015-073407 A.

[0099] The rotation speed calculation unit 73 calculates the rotation speed of the wheel based on the calculated rotation angle. Specifically, for example, the rotation speed calculation unit 73 may calculate the rotation speed based on the time derivative value of the rotation angle.

[0100] 31 shows the procedure of the load and rotation speed calculation process executed by the processing unit 70. This process is executed repeatedly at a predetermined control period, for example.

[0101] In step S10, the first and second displacement signals, the first and second output voltage signals v1 and v2 are acquired from the receiving circuit 95.

[0102] In step S11, the axial displacement ΔY is calculated based on the acquired first and second displacement signals, and in step S12, the vertical displacement ΔZ is calculated based on the acquired first and second displacement signals.

[0103] In step S13, the lateral force Fy is calculated based on the calculated axial displacement ΔY, and in step S14, the vertical load Fz is calculated based on the calculated vertical displacement ΔZ.

[0104] In step S15, the rotation angle of the wheel is calculated based on at least one of the first output voltage signal v1 and the second output voltage signal v2, and the rotation speed of the wheel is calculated based on the calculated rotation angle.

[0105] As described above, according to this embodiment, in the sensor-equipped bearing module used to calculate the load and rotational speed, the space around the hub bearing 40 can be effectively used as space for arranging the target member 80 and the detection unit 90.

[0106] Modification of First Embodiment The number of divisions of the target member 80 is not limited to two, and it may be divided into, for example, three or four (for example, equally divided in the circumferential direction).

[0107] Second Embodiment A second embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in Fig. 32 , a ring member 86 is not used to attach the target member 80 to the flange portion 62. More specifically, the outer peripheral edge of the flange portion 62 is pressed from the outside in the radial direction against the inner peripheral surface of the inner peripheral wall portion 82 that constitutes the target member 80. In this way, the target member 80 is fixed to the flange portion 62.

[0108] According to the present embodiment described above, the number of parts constituting the wheel unit 10 can be reduced.

[0109] Third Embodiment A third embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in Figures 33 and 34, a target member 180 is fixed to the hub bearing 40 with a bolt 184.

[0110] As in the first embodiment, the target member 180 is made up of a first divided member 180A and a second divided member 180B. However, in each divided member 180A, 180B, a flat surface 182 that abuts (specifically, makes surface contact with) the mounting surface 62a of the flange portion 62 is formed on the portion opposite to the surface on which the convex portion 84 and the concave portion 85 are formed.

[0111] The flange portion 62 has through holes 62b, through which the bolts 184 are inserted, formed side by side in the circumferential direction. The through holes 62b are formed at positions shifted in the circumferential direction from the positions at which the hub bolts 17 protrude.

[0112] Each divided member 180A, 180B has a female screw hole 183 that opens from the flat surface 182 side. The female screw hole 183 does not penetrate all the way to the surface of each divided member 180A, 180B where the convex portion 84 and the concave portion 85 are formed. With the flat surface 182 of each divided member 180A, 180B abutting against the mounting surface 62a and the bolt 184 inserted into the through hole 62b, the male thread of the bolt 184 is screwed into the female screw hole 183. In this way, each divided member 180A, 180B is fixed to the flange portion 62.

[0113] When viewed from the front of the mounting surface 62a, the side surface portion 181 of the target member 180 does not protrude from the flange portion 62. This makes it possible to suppress an increase in the radial dimension of the sensor-equipped bearing module.

[0114] According to the present embodiment described above, the space around the hub bearing 40 can also be effectively used as a space for arranging the target member 180 and the detection unit 90.

[0115] Fourth Embodiment A fourth embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, as shown in Figure 35 , a hub bearing 240 is fixed to the disc mounting portion 18 of the wheel 11, and a disc rotor 221 is fixed to a flange portion 262 of the hub bearing 240.

[0116] In the wheel unit 200, the disc rotor 221 has a hat portion 222 and a sliding portion 223. The hat portion 222 is attached to a hub bearing 240. The front and back surfaces of the sliding portion 223 form a pair of sliding surfaces that are pressed against by disc pads that constitute a brake caliper 233.

[0117] The hub bearing 240 is a rolling bearing and includes an outer ring 250 (corresponding to the "second bearing portion"), an inner ring 260 (corresponding to the "first bearing portion"), and a plurality of rolling elements 241 arranged between the outer ring 250 and the inner ring 260.

[0118] The inner ring 260 includes an inner cylindrical portion 261 (corresponding to a "first cylindrical portion") extending in the axial direction, and a flange portion 262 extending radially from a first end of the inner cylindrical portion 261 in the axial direction.

[0119] The outer ring 250 has an outer cylindrical portion 251 (corresponding to a "second cylindrical portion") provided at a position facing radially outward from the inner cylindrical portion 261. The outer ring 250 has a hub attachment portion 252 that protrudes radially outward from the outer cylindrical portion 251. The hub attachment portion 252 is fixed with bolts 253 to the knuckle 215 serving as a base portion.

[0120] The flange portion 262 is disk-shaped and extends radially outward beyond the outer cylindrical portion 251. The disc mounting portion 18 is fixed to a portion of the flange portion 262 that is outer in the vehicle width direction, and the hat portion 222 of the disc rotor 221 is fixed to a portion of the flange portion 262 that is inner in the vehicle width direction.

[0121] As with the first embodiment, the wheel unit 200 includes, as a detection device, an annular target member 280 and a detection unit 290. The target member 280 is fixed to the inner portion of the flange portion 62 in the vehicle width direction, radially outward of the hat portion 222. The detection unit 290 is provided at a position facing the target member 280 in the axial direction. The detection unit 290 is fixed to a bracket 291, and the bracket 291 is fixed to the knuckle 215.

[0122] According to the present embodiment described above, the space around the hub bearing 240 can be effectively used as a space for arranging the target member 280 and the detection unit 290 .

[0123] Fifth Embodiment A fifth embodiment will now be described with reference to the drawings, focusing on differences from the fourth embodiment. In this embodiment, as shown in Figure 36, a spindle-type hub bearing is used.

[0124] The wheel unit 300 includes a brake device and a hub bearing 340 (corresponding to a "bearing member"). The brake device includes a disc rotor 321 and a brake caliper 333.

[0125] The disc rotor 321 has a hat portion 322 and a sliding portion 323. The hat portion 322 is attached to a hub bearing 340. The front and back surfaces of the sliding portion 323 form a pair of sliding surfaces that are pressed against by disc pads of a brake caliper 333.

[0126] The hub bearing 340 includes a spindle shaft 341 fixed to a base portion 315, a rotating shaft 342, a cylindrical portion 343, a flange portion 344, and a bearing 345. The base portion 315 is, for example, a knuckle of a vehicle or a housing mounted on the vehicle. The housing is, for example, the housing of an electric axle in which a motor, an inverter, and a transmission are integrated.

[0127] The spindle shaft 341 extends outward in the vehicle width direction from the base portion 315. A through-hole is formed in the rotating shaft 342, penetrating it in the axial direction, and the rotating shaft 342 is inserted into this through-hole. Rotational power is applied to the rotating shaft 342 from a motor or the like, which serves as a power source for running the vehicle.

[0128] The cylindrical portion 343 is provided radially outward of the spindle shaft 341 and is rotatably supported on the spindle shaft 341 via a bearing 345. The bearing 345 is a rolling bearing. A flange portion 344 extends radially outward from the axial end of the cylindrical portion 343.

[0129] A ring-shaped target member 380 is fixed to the inner portion of the flange portion 344 in the vehicle width direction. As described in the first embodiment, the target member 380 has protrusions and recesses arranged in the circumferential direction. A detection unit 390 is provided at a position facing the target member 380 in the axial direction. The detection unit 390 is fixed to the base portion 315 via a bracket 391.

[0130] According to the present embodiment described above, it is possible to achieve the same effects as those of the fourth embodiment.

[0131] Other Embodiments The above-described embodiments may be modified as follows.

[0132] 37 , the wheel unit 300 of the fifth embodiment may include a drum brake instead of a disc brake as the braking device 320. The braking device 320 includes a brake shoe 324. The braking device 320 is provided on the radially outer side of the cylindrical portion 343.

[0133] The target member may be as shown in FIG. 38 . The target member 480 is made of a metal material (e.g., aluminum or iron) and includes an annular ring portion 486 and a plurality of shielding portions 484. The shielding portions 484 protrude radially inward from the ring portion 486 and are arranged side by side in the circumferential direction. A notch 485 is formed between adjacent shielding portions 484 in the circumferential direction. The shielding portions 484 correspond to the convex portions 84 of the first embodiment, and the notch 485 corresponds to the concave portions 85 of the first embodiment. In FIG. 38 , 484 a denotes the radially inner end of the ring portion 486 and the radially outer end of the shielding portion 484, and 484 b denotes the radially inner end of the shielding portion 484. The notch 485 may be filled with a non-metallic material (e.g., synthetic resin).

[0134] As shown in Figure 39, a hub bearing 440 may have an outer ring 460 (corresponding to the "first bearing portion") that rotates with the wheel 11, and an inner ring 450 (corresponding to the "second bearing portion") that is fixed to a base portion. The outer ring 460 has an outer cylindrical portion 461 (corresponding to the "first cylindrical portion") and a flange portion 462. The inner ring 450 has an inner cylindrical portion 451 (corresponding to the "second cylindrical portion") and a hub mounting portion 452 that protrudes radially outward from the inner cylindrical portion 451. The hub mounting portion 452 is fixed to the base portion with bolts (not shown).

[0135] The coil unit 92 may be configured so that the phase difference between the second output voltage signal v2 of the second receiver coil 120 and the first output voltage signal v1 of the first receiver coil 110 is a predetermined phase other than 90 degrees. The predetermined phase is, for example, a phase greater than or equal to 30 degrees and less than or equal to 70 degrees.

[0136] The two receiving coils formed on the substrate 91 may be coils of the same shape (for example, the second receiving coil 120). In this case, the phases of the induced voltages in the two receiving coils are the same.

[0137] The number of receiving coils provided on the substrate 91 is not limited to two, and may be, for example, one.

[0138] The substrate 91 may be provided at a position where the circumferential central axis Lt of the first and second receiving coils 110, 120 is axially opposite to the lower end of the detection rotating part 81, rather than at a position where the circumferential central axis Lt is axially opposite to the upper end of the detection rotating part 81.

[0139] The substrate 91 may be provided so that the circumferential central axes Lt of the first and second receiving coils 110, 120 are axially opposed to the right or left end of the detection rotating portion 81, rather than being axially opposed to the upper end of the detection rotating portion 81. In this case, the detection unit 90 can calculate the force acting between the ground contact surface GL and the wheel in the vehicle length direction (hereinafter referred to as the longitudinal load Fx) instead of the vertical load Fz. The direction in which the lateral force Fy acts is perpendicular to the direction in which the longitudinal load Fx acts. The longitudinal load Fx is used by the control device to control the running of the vehicle.

[0140] The longitudinal load Fx is assumed to be positive when the vehicle accelerates, and negative when the vehicle decelerates. When the longitudinal load Fx is positive, the convex portion 84 is displaced toward the vehicle traveling direction. This state corresponds to the state in the first embodiment where the upward vertical load acting on the wheel increases. On the other hand, when the longitudinal load Fx is negative, the convex portion 84 is displaced toward the opposite side of the vehicle traveling direction. This state corresponds to the state in the first embodiment where the downward vertical load acting on the wheel increases.

[0141] As in the first embodiment, the receiving circuit 95 outputs the deviation amount of the actual amplitude of the first envelope curve ENV1 from the amplitude of the first envelope curve ES1 in the reference state as a first displacement signal to the processing unit 70. The receiving circuit 95 also outputs the deviation amount of the actual amplitude of the second envelope curve ENV2 from the amplitude of the second envelope curve ES2 in the reference state as a second displacement signal to the processing unit 70.

[0142] The displacement calculation unit 71 calculates the axial displacement ΔY and the vehicle length direction displacement ΔX based on the first and second displacement signals and map information or mathematical formula information in which the first and second displacement signals, the axial displacement ΔY, and the vehicle length direction displacement ΔX are correlated.

[0143] The force calculation unit 72 calculates the lateral force Fy based on the calculated axial displacement ΔY and map information or formula information correlating the axial displacement ΔY and the lateral force Fy. The force calculation unit 72 calculates the longitudinal load Fx based on the calculated vehicle lengthwise displacement ΔX and map information or formula information correlating the vehicle lengthwise displacement ΔX and the longitudinal load Fx.

[0144] The processing unit 70 may execute only either the load calculation process or the rotational speed calculation process.

[0145] The rotor of the motor that serves as the vehicle's driving power source may be arranged to rotate integrally with the hub bearing or to rotate via a transmission. The rotor has field poles (e.g., permanent magnets or electromagnets with field windings). In this case, the processing unit 70 may calculate the rotation angle of the rotor (specifically, the electrical angle or mechanical angle). For example, by correlating and setting the circumferential spacing between the rotor's magnetic pole positions with the circumferential lengths of the protrusions 84 and recesses 85, it is possible to associate the amplitude or envelope with the electrical angle θe. The calculated rotation angle is used, for example, to control the motor.

[0146] In each of the above embodiments, the target member may be fixed to the base portion, such as a knuckle, instead of the wheel 11, and the detection unit may be fixed to the wheel 11 instead of the base portion.

[0147] The disk rotor is not limited to a ventilated disk, but may be, for example, a solid disk made of a single circular plate.

[0148] The mechanical devices to which the detection device can be applied are not limited to wheel units, but may also be, for example, aircraft equipped with a propeller as a rotating body, ships equipped with a screw as a rotating body, internal combustion engines equipped with a crankshaft as a rotating body, or generators equipped with a turbine as a rotating body.

[0149] Furthermore, the rotating body is not limited to being used with the axial direction of the rotating body being horizontal, but may also be used with the axial direction being in a direction other than horizontal (for example, up and down).

[0150] The control device and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and method described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the control device and method described herein may be implemented by one or more special-purpose computers configured with a combination of a processor and memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0151] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A detection device applied to a mechanical device (10, 200, 300), the mechanical device comprising: a rotating body (11, 14, 21, 221, 321); and a bearing member (40, 240, 340, 440) that rotatably supports the rotating body relative to a base portion (15, 215, 315), the bearing member having a cylindrical portion (61, 461) extending in the axial direction of the bearing member, and a flange portion (62, 262, 344, 462) extending in the radial direction of the bearing member from a first end of the cylindrical portion in the axial direction and to which the rotating body is fixed, rotatably supporting the cylindrical portion and the flange portion relative to the base portion, the flange portion extending radially outward beyond the cylindrical portion, a target member (80, 180, 280, 380) provided in an arrangement space that is adjacent to the flange portion on the side of the second end of the cylindrical portion in the axial direction and that is a space outer than the cylindrical portion in the radial direction; and a displacement detection unit (90, 290, 390) provided in the arrangement space at a position facing the target member in the axial direction, wherein the target member forms an annular ring extending in the circumferential direction of the bearing member around the center of rotation of the bearing member, one of the target member and the displacement detection unit is fixed to the flange portion and the other is fixed to the base portion, and the displacement detection unit outputs a voltage signal corresponding to the relative displacement of the target member with respect to the displacement detection unit. [Configuration 2] The detection device according to Configuration 1, wherein the cylindrical portion is a first cylindrical portion, and the bearing member has: a first bearing portion (60, 460) having the first cylindrical portion and the flange portion (62, 462), a second cylindrical portion (51, 451) provided at a position opposite to the first cylindrical portion in the radial direction, the second bearing portion (50, 450) being fixed to the base portion, and rolling elements (41, 441) provided between the first bearing portion and the second bearing portion, and rotatably supports the first bearing portion with respect to the base portion, and the flange portion extends radially outward beyond the first cylindrical portion and the second cylindrical portion.[Configuration 3] The detection device according to Configuration 2, wherein the displacement detection unit is fixed to the base unit, the target member (80, 180, 280) is provided closer to the flange unit than the displacement detection unit (90, 290) in the axial direction, the flange unit is disk-shaped, the target member is provided at a position opposite the displacement detection unit in the axial direction, and has an annular detection rotor (81) extending in the circumferential direction around a rotation center of the first bearing unit, and the displacement detection unit outputs a voltage signal according to a relative displacement of the detection rotor with respect to the displacement detection unit. the target member has an inner peripheral wall portion (82) extending from an outer peripheral edge portion of the detection rotating portion toward the flange portion in the axial direction, the inner peripheral wall portion abutting against the outer peripheral edge portion of the flange portion from the outside in the radial direction, a mounting surface (62a) on which the rotating body is attached is formed on a portion of the flange portion opposite the displacement detection portion in the axial direction, the mounting surface (62a) being a flat surface extending in the radial direction, and the rotating body is attached, and the detection device according to Configuration 3 further comprises: a disk portion (87) having a flat surface (87b) abutting against the mounting surface, and an outer peripheral wall portion (88) abutting against the inner peripheral wall portion from the outside in the radial direction and extending from the outer peripheral edge portion of the disk portion toward the displacement detection portion in the axial direction, wherein the outer peripheral surface of the inner peripheral wall portion is pressed against the inner peripheral surface of the outer peripheral wall portion, and the target member is fixed to the flange portion. [Configuration 5] The detection device of Configuration 4, wherein the outer peripheral edge of the disk portion extends radially outward beyond the tip of the inner peripheral wall portion, the tip of the inner peripheral wall portion abuts against the disk portion, and a stepped portion (88a) is formed at the base end of the outer peripheral wall portion, protruding radially inward, for press-fitting and fixing the tip of the inner peripheral wall portion. [Configuration 6] The detection device of Configuration 4 or 5, wherein the outer peripheral wall portion extends in the axial direction to a position covering the displacement detection portion from the outside in the radial direction. [Configuration 7] The detection device of any one of Configurations 4 to 6, wherein the material of the inner peripheral wall portion and the material of the outer peripheral wall portion are the same.[Configuration 8] The detection device of Configuration 3, wherein the target member (180) abuts against a portion of the flange portion that faces the displacement detection portion in the axial direction, the flange portion has a through hole (62b) formed therein, through which a bolt (184) is inserted and which passes through in the axial direction, the target member has a female threaded hole (183) into which the bolt is screwed, on the flange portion side in the axial direction, and with the target member abutting against the flange portion and the bolt inserted into the through hole, the bolt is screwed into the female threaded hole to fix the target member to the flange portion. [Configuration 9] The detection device of Configuration 3, wherein the target member has an inner peripheral wall portion (82) extending from an outer peripheral edge portion of the detection rotating portion toward the flange portion in the axial direction, and the outer peripheral edge portion of the flange portion is pressed against an inner peripheral surface of the inner peripheral wall portion to fix the target member to the flange portion. [Configuration 10] The detection device according to any one of Configurations 1 to 9, wherein the target member (80A, 80B, 180A, 180B) is divided into a plurality of parts in the circumferential direction. [Configuration 11] The detection device according to any one of Configurations 1 to 10, wherein the mechanical device is a wheel unit (10) including a vehicle wheel (11, 14), and the rotating body is a disk rotor (21) having: a disk circumferential wall portion (25) extending from the flange portion toward the displacement detection unit in the axial direction, and an annular sliding portion (23) extending in the radial direction from an end of the disk circumferential wall portion in the axial direction, and the target member (80, 180) is provided radially inward of the disk circumferential wall portion in the arrangement space. [Configuration 12] The detection device according to Configuration 11, wherein an air passage is formed in the sliding portion, extending from an air intake (31) formed on the inside in the radial direction to an air exhaust port (32) formed on the outside in the radial direction, and the target member is provided at a position opposite the air intake in the radial direction.[Configuration 13] The detection device according to configuration 11 or 12, wherein the mechanical device includes a brake caliper (33), and the displacement detection unit is provided at a position that overlaps with an installation position of the brake caliper in the axial direction and at a position that is separated from the brake caliper in the circumferential direction. [Configuration 14] The detection device according to any one of configurations 11 to 13, wherein the mechanical device includes a heat shield (35) provided more inward in the vehicle width direction than the bearing member and the disc rotor, and the heat shield extends in the radial direction to a position that faces the displacement detection unit in the axial direction, and an insertion hole (35a) for inserting wiring (97) extending from the displacement detection unit is formed in a portion of the heat shield that faces the displacement detection unit in the axial direction. [Configuration 15] The detection device according to Configuration 1, wherein the displacement detection unit is fixed to the base unit, and the target member (280, 380) is provided on a portion of the flange unit (262, 344) that faces the displacement detection unit (290, 390) in the axial direction. [Configuration 16] The detection device according to any one of Configurations 1 to 15, wherein the detection rotating unit has a configuration in which recesses (85) recessed in the axial direction and protrusions (84) protruding in the axial direction relative to the recesses are alternately provided in the circumferential direction, or a configuration in which metal portions (484) and portions (485) penetrated in the axial direction are alternately provided in the circumferential direction.[Configuration 17] The displacement detection unit includes: two planar receiving coils (110, 120) fixed to the base unit and provided at a position facing an upper end or a lower end of the detection rotating unit in the axial direction, extending in a direction intersecting the axial direction; and an excitation coil (100) to which an AC excitation voltage is supplied, wherein a voltage is induced in each receiving coil when the excitation voltage is supplied to the excitation coil, and when viewed from above, the radially outer end of one of the receiving coils (120) protrudes from the radially outer end (84a) of the detection rotating unit, and the radially outer ends of the receiving coils are positioned differently in the radial direction. The detection device described in any one of configurations 1 to 16. [Configuration 18] The detection device according to Configuration 17, further comprising a force calculation unit (72) that calculates a force acting on the rotating body based on an output voltage signal of each of the receiving coils. [Configuration 19] A module comprising: the detection device according to any one of Configurations 1 to 18; and the bearing member.

[0152] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A detection device applied to a mechanical device (10, 200, 300), the mechanical device comprising: a rotating body (11, 14, 21, 221, 321); and a bearing member (40, 240, 340, 440) that rotatably supports the rotating body relative to a base portion (15, 215, 315), the bearing member having a cylindrical portion (61, 461) extending in the axial direction of the bearing member, and a flange portion (62, 262, 344, 462) that extends in the radial direction of the bearing member from a first end of the cylindrical portion in the axial direction and to which the rotating body is fixed, and rotatably supports the cylindrical portion and the flange portion relative to the base portion, the flange portion extending radially outward beyond the cylindrical portion, a target member (80, 180, 280, 380) provided in an arrangement space which is adjacent to the flange portion in the axial direction on the side of the second end of the cylindrical portion and which is an outer space than the cylindrical portion in the radial direction; and a displacement detection unit (90, 290, 390) provided in the arrangement space at a position opposite the target member in the axial direction, wherein the target member forms a ring shape extending in the circumferential direction of the bearing member around the center of rotation of the bearing member, one of the target member and the displacement detection unit is fixed to the flange portion and the other is fixed to the base portion, and the displacement detection unit outputs a voltage signal corresponding to the relative displacement of the target member with respect to the displacement detection unit.

2. The detection device described in claim 1, wherein the cylindrical portion is a first cylindrical portion, the bearing member has a first bearing portion (60, 460) having the first cylindrical portion and the flange portion (62, 462), a second cylindrical portion (51, 451) provided at a position opposite to the first cylindrical portion in the radial direction, the second bearing portion (50, 450) being fixed to the base portion, and rolling elements (41, 441) provided between the first bearing portion and the second bearing portion, and rotatably supports the first bearing portion relative to the base portion, and the flange portion extends radially outward beyond the first cylindrical portion and the second cylindrical portion.

3. The detection device described in claim 2, wherein the displacement detection unit is fixed to the base portion, the target member (80, 180, 280) is provided on the flange portion side of the displacement detection unit (90, 290) in the axial direction, the flange portion is disk-shaped, the target member is provided at a position opposite the displacement detection unit in the axial direction and has an annular detection rotating portion (81) extending in the circumferential direction around the center of rotation of the first bearing portion, and the displacement detection unit outputs a voltage signal corresponding to the relative displacement of the detection rotating portion with respect to the displacement detection unit.

4. The detection device described in claim 3, wherein the target member (80) has an inner peripheral wall portion (82) extending from an outer circumferential edge portion of the detection rotating portion toward the flange portion in the axial direction, the inner peripheral wall portion abutting against the outer circumferential edge portion of the flange portion from the outside in the radial direction, a mounting surface (62a) on which the rotating body is attached is formed on a portion of the flange portion opposite the displacement detection portion (90) in the axial direction, which is a flat surface extending in the radial direction, and a disk portion (87) having a flat surface (87b) abutting against the mounting surface, and an outer peripheral wall portion (88) abutting against the inner peripheral wall portion from the outside in the radial direction and extending from the outer circumferential edge portion of the disk portion toward the displacement detection portion in the axial direction, and a fixing member (86) having the following:

5. A detection device as described in claim 4, wherein the outer peripheral edge of the disc portion extends radially outward beyond the tip of the inner peripheral wall portion, the tip of the inner peripheral wall portion abuts against the disc portion, and a step portion (88a) is formed at the base end of the outer peripheral wall portion, protruding radially inward, for press-fitting and fixing the tip of the inner peripheral wall portion.

6. A detection device as described in claim 4 or 5, wherein the outer peripheral wall portion extends in the axial direction to a position covering the displacement detection portion from the outside in the radial direction.

7. A detection device as claimed in claim 4 or 5, wherein the material of said inner peripheral wall portion and the material of said outer peripheral wall portion are the same.

8. A detection device as described in claim 3, wherein the target member (180) abuts against a portion of the flange portion that faces the displacement detection portion in the axial direction, the flange portion has a through hole (62b) formed therein and a bolt (184) is inserted therethrough, and the target member has a female threaded hole (183) into which the bolt is screwed formed on the flange portion side in the axial direction, and with the target member abutting against the flange portion and the bolt inserted through the through hole, the bolt is screwed into the female threaded hole to fix the target member to the flange portion.

9. A detection device as described in claim 3, wherein the target member has an inner peripheral wall portion (82) extending from the outer peripheral edge portion of the detection rotating portion toward the flange portion in the axial direction, and the outer peripheral edge portion of the flange portion is pressed against the inner peripheral surface of the inner peripheral wall portion to fix the target member to the flange portion.

10. A detection device according to any one of claims 1 to 5, 8 and 9, wherein the target member (80A, 80B, 180A, 180B) is divided into a plurality of parts in the circumferential direction.

11. The mechanical device is a wheel unit (10) equipped with a vehicle wheel (11, 14), and the rotating body is a disk rotor (21) having a disk circumferential wall portion (25) extending from the flange portion in the axial direction toward the displacement detection portion, and an annular sliding portion (23) extending in the radial direction from the axial end of the disk circumferential wall portion, and the target member (80, 180) is provided in the arrangement space, radially inward from the disk circumferential wall portion. A detection device as described in any one of claims 1 to 5, 8 and 9.

12. A detection device as described in claim 11, wherein the sliding portion has an air passage extending from an air intake (31) formed on the radial inside to an air exhaust (32) formed on the radial outside, and the target member is provided at a position opposite the air intake in the radial direction.

13. The detection device according to claim 11, wherein the mechanical device comprises a brake caliper (33), and the displacement detection unit is provided at a position that overlaps with an installation position of the brake caliper in the axial direction and is spaced apart from the brake caliper in the circumferential direction.

14. The detection device described in claim 11, wherein the mechanical device includes a heat shield (35) provided inward in the vehicle width direction from the bearing member and the disc rotor, the heat shield extending in the radial direction to a position facing the displacement detection unit in the axial direction, and a through hole (35a) is formed in the portion of the heat shield facing the displacement detection unit in the axial direction, through which wiring (97) extending from the displacement detection unit can be inserted.

15. A detection device as described in claim 1, wherein the displacement detection portion is fixed to the base portion, and the target member (280, 380) is provided on a portion of the flange portion (262, 344) that faces the displacement detection portion (290, 390) in the axial direction.

16. A detection device as claimed in any one of claims 1 to 5, 8, 9 and 15, wherein the detection rotating portion is configured such that concave portions (85) recessed in the axial direction and convex portions (84) protruding in the axial direction relative to the concave portions are alternately provided in the circumferential direction, or such that metal portions (484) and portions (485) pierced in the axial direction are alternately provided in the circumferential direction.

17. The detection device described in any one of claims 1 to 5, 8, 9 and 15, wherein the displacement detection unit has two planar receiving coils (110, 120) fixed to the base unit and disposed at a position facing the upper end or lower end of the detection rotating unit in the axial direction, extending in a direction intersecting the axial direction, and an excitation coil (100) to which an AC excitation voltage is supplied, wherein a voltage is induced in each of the receiving coils when the excitation voltage is supplied to the excitation coil, wherein, in a planar view of each of the receiving coils, the radial outer end of one of the receiving coils (120) protrudes from the radial outer end (84a) of the detection rotating unit, wherein the radial outer ends of the receiving coils are positioned differently in the radial direction, and each of the receiving coils outputs a voltage signal corresponding to a displacement in the axial direction and a displacement perpendicular to the axial direction.

18. The detection device according to claim 17, further comprising a force calculation unit (72) that calculates the force acting on the rotating body based on the output voltage signals of the respective receiving coils.

19. A module comprising: a detection device according to any one of claims 1 to 5, 8, 9 and 15; and the bearing member.

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