Detection device and program

Abstract

The present invention provides a detection device that can reduce the impact of thermal displacement on the detection target while suppressing the occurrence of problems. [Solution] The detection device is applied to a mechanical device. The mechanical device comprises a rotating body and a hub bearing. The hub bearing has a first bearing portion fixed to a base portion, a second bearing portion to which the rotating body is fixed, and rolling elements, and rotatably supports the second bearing portion with respect to the base portion. The detection device comprises an annular target member 80 fixed to the second bearing portion and extending in the circumferential direction of the second bearing portion with respect to the rotation center of the second bearing portion, and a signal output provided at a position facing the detection target portion in the axial direction. A portion of the target member 80 in the circumferential direction is a thermal displacement portion Rb. The thermal displacement portion Rb is a portion of the target member 80 in which the amount of thermal displacement in the axial direction due to temperature changes of the target member 80 is larger than that of the fixed portion Ra other than the thermal displacement portion Rb.

Description

Technical Field

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

Background Art

[0002] Conventionally, a hub bearing with a sensor that detects displacement by utilizing the relative displacement of an inner ring member with respect to an outer ring member of a hub bearing is known. The hub bearing with a sensor is described in, for example, Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A detection device applied to a mechanical device is known. The mechanical device includes a rotating body and a hub bearing. The hub bearing includes a first bearing member (e.g., an outer ring member), a second bearing member (e.g., an inner ring member), and rolling elements. The first bearing member has a first cylindrical portion extending in the axial direction, which is the direction in which the rotation center axis of the hub bearing extends, and is fixed to a base portion (e.g., a knuckle) of the mechanical device. The second bearing member has a second cylindrical portion provided at a position facing the first cylindrical portion in the radial direction orthogonal to the axial direction, and the rotating body is fixed thereto. Rolling elements are provided between the first cylindrical portion and the second cylindrical portion. Thereby, the hub bearing supports the rotating body rotatably with respect to the base portion.

[0005] The detection device comprises a detection target unit and a signal output unit. The detection target unit is fixed to the second bearing unit. In this case, the second bearing unit and the detection target unit rotate together with the rotating body. The signal output unit is positioned opposite the detection target unit in a predetermined direction. The signal output unit outputs a voltage signal that fluctuates according to the relative displacement of the detection target unit with respect to the signal output unit.

[0006] Incidentally, the detection target may undergo thermal displacement due to temperature changes in that part. In this case, there is concern that the thermal displacement of the detection target may affect the voltage signal output from the signal output unit.

[0007] For example, Patent Document 1 describes installing sensors in multiple locations to reduce the influence of thermal displacement on the sensor's detection signal. However, there are concerns that installing sensors in multiple locations may lead to disadvantages such as reduced sensor mounting capacity and increased costs for the detection device.

[0008] The primary purpose of this disclosure is to provide a detection device and program that can reduce the influence of thermal displacement of the detection target while suppressing the occurrence of problems. [Means for solving the problem]

[0009] This disclosure relates to a detection device applied to a machine or apparatus, The aforementioned mechanical device is A solid of rotation and A hub bearing that rotatably supports the aforementioned rotating body relative to the base portion, Equipped with, The aforementioned hub bearing is The hub bearing has a first cylindrical portion that extends in the axial direction, which is the direction in which the rotational axis of the hub bearing extends, and a first bearing portion that is fixed to the base portion, It has a second cylindrical portion provided at a position opposite the first cylindrical portion in the radial direction perpendicular to the axial direction, and a second bearing portion to which the rotating body is fixed, A rolling element provided between the first bearing portion and the second bearing portion, It has the following features, and the second bearing portion is rotatably supported with respect to the base portion, A detection target portion is fixed to the second bearing portion and extends in the circumferential direction of the second bearing portion with respect to the rotation center of the second bearing portion, A signal output unit is provided at a position opposite to the detection target unit in the axial direction, Equipped with, The signal output unit outputs a voltage signal that changes according to the relative displacement of the detection target unit with respect to the signal output unit. A portion of the detection target in the circumferential direction is defined as a thermally displaced portion. The thermal displacement portion is a portion of the detection target that has a larger amount of thermal displacement in the axial direction due to temperature changes in the detection target compared to the portion of the detection target other than the thermal displacement portion.

[0010] In this disclosure, the detection target has a thermal displacement portion. The thermal displacement portion is a part of the detection target in the circumferential direction, and is a portion of the detection target that has a larger relative displacement due to temperature changes compared to the portion of the detection target other than the thermal displacement portion. In this case, by making the amount of thermal displacement different between the thermal displacement portion and the portion of the detection target other than the thermal displacement portion, it is possible to intentionally superimpose the effect of the thermal displacement of the detection target onto the voltage signal output from the sensor substrate. As a result, the voltage signal output from the signal output unit can be made into a voltage signal that can grasp the effect of the thermal displacement of the detection target. As a result, it is possible to reduce the influence of the thermal displacement of the detection target while suppressing the occurrence of inconveniences caused by the additional installation of a detection device on the machine. [Brief explanation of the drawing]

[0011] [Figure 1] A perspective view of the wheel unit according to the first embodiment. [Figure 2] A longitudinal cross-sectional view of the wheel unit near the hub bearing. [Figure 3] Plan view of the target component. [Figure 4] Circumferential cross-sectional view of the first divided member. [Figure 5]Circumferential cross-sectional view of the second dividing member. [Figure 6] Diagram showing the electrical configuration of the sensor substrate and the processing unit. [Figure 7] Flowchart showing the procedure of the process executed by the processing unit. [Figure 8] Diagram showing an example of the shape of the thermal displacement portion. [Figure 9] Diagram for explaining the case where the fixed portion is thermally displaced. [Figure 10] Diagram for explaining the case where the thermal displacement portion is thermally displaced. [Figure 11] Diagram showing an example of the relationship between the rotation angle and the axial displacement. [Figure 12] Time chart showing the transition of the combined displacement component of the axial displacement. [Figure 13] Diagram showing the relationship between the difference in axial displacement in the thermal displacement portion and the fixed portion and the temperature of the target member. [Figure 14] Flowchart showing the procedure of the correction process executed by the processing unit. [Figure 15] Diagram showing an example of the shape of the thermal displacement portion according to a modification of the first embodiment. [Figure 16] Exploded perspective view of the hub bearing and the target member. [Figure 17] Diagram for explaining the shape of the thermal displacement portion. [Figure 18] Plan view of the target member according to the second embodiment. [Figure 19] Diagram for explaining the case where the thermal displacement portion is thermally displaced.

Embodiments for Carrying Out the Invention

[0012] A plurality of embodiments will be described while referring to the drawings. In the plurality of embodiments, parts that are functionally and / or structurally corresponding and / or associated may be assigned the same reference numerals, or reference numerals that differ in the hundreds or more digits. For corresponding parts and / or associated parts, the description of other embodiments can be referred to.

[0013] <First Embodiment> Hereinafter, a first embodiment of the detection device relating to this disclosure will be described with reference to the drawings. The detection device of this embodiment is configured to calculate the 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 (e.g., private or commercial) having two front wheels and two rear wheels. However, the vehicle is not limited to this, and may be a two-wheeled vehicle or other vehicle with a different number of wheels. Furthermore, the use of the vehicle is not limited to passenger use.

[0014] The wheel unit 10 as a mechanical device will be explained using Figures 1 and 2. Figure 1 is a perspective cross-sectional view of the wheel unit 10 partially cut, and Figure 2 is a cross-sectional view of the wheel unit 10 cut by a plane that passes through the center of rotation of the wheel unit 10 and extends vertically.

[0015] As shown in Figure 1, the wheel unit 10 comprises a wheel 11 and a tire 14. The wheel 11 comprises 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 comprises a disc mounting portion 18 located in the center of the disc portion 13 and spoke portions 19 extending radially from the disc mounting portion 18 to the rim portion 12. The tire 14 is attached to the outer circumference of the rim portion 12.

[0016] As shown in Figures 1 and 2, the wheel unit 10 includes a brake device 20 and a hub bearing 40. The brake device 20 is a disc-type friction brake device and includes a disc rotor 21 which is disc-shaped overall and a brake caliper (not shown). The brake caliper has a pair of disc pads which are operated by hydraulic pressure or an electrical signal and come into contact with the disc rotor 21 to generate braking force, a piston which presses the disc pads against the disc rotor 21, and a caliper body which supports the brake pads and piston. The brake caliper is fixed to the knuckle 15 which is the base part.

[0017] 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 sliding portion 23 is connected to the hat portion 22. The front and back surfaces of the sliding portion 23 are a pair of sliding surfaces that are pressed against by the disc pad. The disc rotor 21 is, for example, a ventilated disc having a cavity inside for ventilation.

[0018] In the following, the direction in which the rotational axis of the hub bearing 40 (specifically, for example, the inner ring member 60 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.

[0019] The hub bearing 40 is a rolling bearing (specifically a radial ball bearing) and comprises an outer ring member 50 (corresponding to the "first bearing member"), an inner ring member 60 (corresponding to the "second bearing member"), and a plurality of rolling elements 41 (specifically balls) arranged between the outer ring member 50 and the inner ring member 60. In this embodiment, the hub bearing 40 has a structure in which the rolling elements 41 are arranged in two rows in the axial direction. The hub bearing 40 may also be a radial roller bearing with rollers as the rolling elements 41.

[0020] The inner ring member 60 comprises an inner cylindrical portion 61 (corresponding to the "second cylindrical portion") extending in the axial direction and a flange portion 62 extending radially from the end of the inner cylindrical portion 61 in the axial direction. A shaft insertion hole 63 is formed in the inner cylindrical portion 61, penetrating in the axial direction. A spline is formed on the inner circumferential surface of the shaft insertion hole 63. A shaft (not shown), to which rotational power from a driving power source such as a motor is transmitted, is fitted into the shaft insertion hole 63.

[0021] The outer ring member 50 includes an outer cylindrical portion 51 (corresponding to the "first cylindrical portion") provided at a position facing radially outward from the inner cylindrical portion 61. Rolling elements 41 are provided between the outer cylindrical portion 51 and the inner cylindrical portion 61.

[0022] The flange portion 62 is disc-shaped and extends radially beyond the outer cylindrical portion 51. Multiple bolt insertion holes 64 are formed in the flange portion 62, arranged in the circumferential direction, through which hub bolts 17 for fixing the wheel 11 are inserted.

[0023] The wheel 11 and disc rotor 21 are fixed to the flange portion 62. Specifically, as shown in Figure 2, the disc mounting portion 18 has a bolt insertion hole 18a that penetrates in the axial direction. The hat portion 22 of the disc rotor 21 has a disc-shaped bottom portion 24. The bottom portion 24 has a bolt insertion hole 27 that penetrates in the axial direction. The flange portion 62 has a mounting surface 62b which is a flat surface that abuts (specifically, makes surface contact) with the bottom portion 24. With the bottom portion 24 and the disc mounting portion 18 overlapping the mounting surface 62b of the flange portion 62, hub bolts 17 are inserted through the bolt insertion holes 18a, 27, and 64. The disc mounting portion 18 and disc rotor 21 are fixed to the hub bearing 40 by screwing nuts 35 onto the hub bolts 17.

[0024] The wheel unit 10 is equipped with a detection device. The detection device is located in the inner space of the wheel 11 and comprises a target member 80 (corresponding to the "detection target part") and a sensor board 100 (corresponding to the "signal output part"). The detection device is for detecting the rotational speed of the wheel, which consists of the wheel 11 and the tire 14, and the force acting between the contact surface (ground) and the wheel (specifically the tire 14). Specifically, the detection device detects the lateral force acting between the contact surface (ground) and the wheel (specifically the tire 14), and the force acting between the contact surface and the wheel perpendicular to the contact surface (hereinafter referred to as the vertical load). The direction in which the lateral force acts and the direction in which the vertical load acts are orthogonal. For example, the calculated rotational speed, lateral force, and vertical load are used in the control device (specifically, the ECU: Electronic Control Unit) installed in the vehicle to control the movement of the vehicle, which is a moving object.

[0025] The structure of the detection device will be described below with reference to Figures 2 and 3.

[0026] As shown in Figure 3, the target member 80 has an annular shape that extends circumferentially around the rotational axis of the hub bearing 40. The target member 80 is positioned opposite the sensor substrate 100 in the axial direction and is provided in a non-contact manner with respect to the sensor substrate 100.

[0027] The target member 80 has detection recesses 82 and detection protrusions 81 that project inward in the vehicle width direction in the axial direction relative to the detection recesses 82, arranged alternately in the circumferential direction. In other words, the detection protrusions 81 project in the axial direction relative to the flange portion 62. The detection recesses 82 are recessed toward the flange portion 62 relative to the detection protrusions 81. The detection protrusions 81 have flat surfaces. The flat surfaces between the detection protrusions 81 arranged in the circumferential direction are defined as detection recesses 82. In this embodiment, the target member 80 is provided with 12 sets of detection protrusions 81 and detection recesses 82.

[0028] In Figure 3, LCi indicates the central axis of the inner ring member 60. In this embodiment, the angle α1 between the axis passing through the central axis LCi and one circumferential end of the detection projection 81 and the axis passing through the other circumferential end of the central axis LCi and the detection projection 81 is equal to the angle α2 between the axis passing through the central axis LCi and one circumferential end of the detection recess 82 and the axis passing through the other circumferential end of the central axis LCi and the detection recess 82. Therefore, the circumferential lengths of the multiple detection projections 81 and the circumferential lengths of the multiple detection recesses 82 are equal.

[0029] Figures 4 and 5 show cross-sectional views of the circumferential cross-section of the target member 80 at a predetermined radial position, as viewed from the radially outer side. For convenience, in Figures 4 and 5, the target member 80 is shown unfolded in a linear fashion in the circumferential direction.

[0030] The target member 80 is located on the inner side of the flange portion 62 in the axial direction, in the vehicle width direction. More specifically, the flange portion 62 has multiple bolt insertion holes 65 that penetrate in the axial direction, arranged in a circumferential direction. Bolts 83 (five are shown as an example in Figures 4 and 5) are inserted through the bolt insertion holes. On the part of the target member 80 opposite to the surface where the detection protrusions 81 and detection recesses 82 are formed, female screw holes 85 extending in the axial direction are formed, through which the bolts 83 are inserted. With the target member 80 in contact with the flange portion 62 and the bolts 83 inserted through the bolt insertion holes 65, the male threads of the bolts 83 are screwed into the female screw holes 85 of the target member 80. This fixes the target member 80 to the flange portion 62. As a result, the target member 80, the disc rotor 21, and the wheel 11 rotate together. Figures 4 and 5 are cross-sectional views of the radial position where the bolt insertion holes 65 are formed in the flange portion 62 and the female screw holes 85 are formed in the target member 80.

[0031] Next, we will explain the sensor board 100.

[0032] The sensor substrate 100 is a so-called eddy current type inductive sensor. The sensor substrate 100 is installed with its plate surface extending in the vertical direction. The sensor substrate 100 is installed in a space adjacent to the flange portion 62 on the inside in the vehicle width direction, and in a space outside the inner cylindrical portion 61 and the outer cylindrical portion 51 in the radial direction. In the installation space, the target member 80 is installed at a position axially opposite to the sensor substrate 100. In this embodiment, the sensor substrate 100 is installed at a position axially opposite to the lower end or upper end of the target member 80.

[0033] The wheel unit 10 is equipped with a substrate mounting member 120. The substrate mounting member 120 is configured to fix the sensor substrate 100 to the outer ring member 50. The substrate mounting member 120 is plate-shaped and annular. The substrate mounting member 120 is made of, for example, synthetic resin or a metal material (for example, aluminum). In the center of the substrate mounting member 120, there is a circular through-hole 122 that penetrates axially from the first plate surface of the substrate mounting member 120 to the second plate surface, which is the back surface of the first plate surface, and into which the outer cylindrical portion 51 is fitted. The first plate surface is the inner surface in the vehicle width direction of the two surfaces of the substrate mounting member 120.

[0034] Although not shown in the diagram, the substrate mounting member 120 has bolt insertion holes that penetrate axially and through which substrate mounting bolts are inserted. On the other hand, the sensor substrate 100 has the same number of female screw holes into which the male threads of the substrate mounting bolts are screwed. The substrate mounting bolts are inserted into the bolt insertion holes from the first plate surface side of the substrate mounting member 120, and the male threads of the substrate mounting bolts are screwed into the female screw holes. As a result, the sensor substrate 100 is fixed to the substrate mounting member 120 while maintaining a predetermined relative positional relationship between the sensor substrate 100 and the substrate mounting member 120. In this case, the plate surface of the sensor substrate 100 and the plate surface of the substrate mounting member 120 are parallel.

[0035] The substrate mounting member 120 has bolt insertion holes 123 that penetrate from the first plate surface to the second plate surface, through which bolts 16 (see Figure 2) are inserted. In this embodiment, three bolt insertion holes 123 are formed, spaced apart in the circumferential direction.

[0036] The wheel unit 10 is equipped with a dust cover 70, which is a heat shield. The dust cover 70 is positioned inward in the vehicle width direction from the hub bearing 40 and the sliding portion 23 of the disc rotor 21. As shown in Figure 2, the dust cover 70 is equipped with a wall portion 73 that extends radially. The wall portion 73 has a circular (specifically, perfectly circular) through hole 72 that extends in a direction perpendicular to the plate surface of the wall portion 73. The outer cylindrical portion 51 of the outer ring member 50 is fitted into the through hole 15a.

[0037] A bolt insertion hole 71 is formed in the wall portion 73 of the dust cover 70 through which a bolt 16 is inserted. A bolt insertion hole 15b is formed in the knuckle 15 through which a bolt 16 is inserted.

[0038] The hub mounting portion 52 of the hub bearing 40 is provided with the same number of bolt insertion holes 123. The hub mounting portion 52 is spaced apart in the circumferential direction. The hub mounting portion 52 has a female screw hole 52a that penetrates axially and into which a bolt 16 is screwed. With the outer cylindrical portion 51 fitted into the through holes 122, 72, and 15a, the bolt 16 is inserted through the bolt insertion holes 15b, 71, and 123, and the male thread of the bolt 16 is screwed into the female screw hole 52a. This fixes the outer ring member 50, the base plate mounting member 120, and the dust cover 70 to the knuckle 15.

[0039] The sensor substrate 100 has an arc shape that follows the target member 80. As shown in Figure 6, the sensor substrate 100 includes an excitation coil 110 and a receiving coil. In this embodiment, the receiving coils are a first receiving coil 111 and a second receiving coil 112. Each coil 110 to 112 is a planar coil that follows the surface of the sensor substrate 100. The sensor substrate 100 is a multilayer substrate. Each coil 110 to 112 is composed of wiring patterns and vias formed in each layer of the sensor substrate 100.

[0040] In this embodiment, each coil 110 to 112 has the same circumferential center position. Furthermore, the circumferential center position of each coil 110 to 112 is located opposite the upper or lower end of the target member 80 in the axial direction.

[0041] The sensor board 100 includes an excitation circuit 113 and a receiving circuit 114. The excitation circuit 113 supplies a high-frequency excitation voltage to the excitation coil 110. This generates a magnetic flux, which links with the receiving coil. A voltage proportional to the time rate of change of the linked magnetic flux is induced at both ends of each receiving coil 111, 112. The receiving circuit 114 detects the voltage induced at both ends of each receiving coil 111, 112.

[0042] The sensor board 100 is provided with a connector 115 that is electrically connected to the excitation circuit 113 and the receiving circuit 114. The connector 115 is electrically connected to the processing unit 117 via a cable 116. The output voltages of each coil 111 and 112 detected by the receiving circuit 114 are input to the processing unit 117 as voltage signals. The processing unit 117 may be located on the vehicle body or built into the wheel unit 10.

[0043] The processing unit 117 includes a CPU (Central Processing Unit). The functions provided by the processing unit 117 can be provided by software recorded in a physical memory device and the computer that executes it, by software only, by hardware only, or by a combination thereof. For example, if the microcontroller of the processing unit 117 is provided by hardware electronic circuits, it can be provided by digital circuits including a large number of logic circuits, or by analog circuits. For example, the microcontroller executes a program stored in a non-transitory tangible storage medium that it has as its memory unit. The program includes, for example, programs like those shown in Figures 7 and 14. The method corresponding to the program is executed by executing a set of instructions that constitute the program. The memory unit is, for example, non-volatile memory. The program stored in the memory unit can be updated via a communication network such as the Internet, for example, OTA (Over The Air).

[0044] Next, the process for calculating the relative displacement of the target member 80 with respect to the sensor substrate 100 and the force acting on the wheel will be described. This process is performed by the processing unit 117.

[0045] The target member 80 is made of a conductive material, specifically a metallic material such as aluminum or iron. In this case, eddy currents flow in the portion of the target member 80 that faces each coil 111, 112 due to the flux linkage caused by the energization of the excitation coil 110. The eddy currents flowing through the target member 80 generate a magnetic flux in a direction that weakens the magnetic flux that generates an induced voltage in each coil 111, 112. Depending on the distance between the sensor substrate 100 and the target member 80, the magnitude of the eddy currents flowing through the target member 80 changes, and at least one of the output voltages of each coil 111, 112 changes. The processing unit 117 calculates the relative displacement of the target member 80 with respect to the sensor substrate 100 based on the output voltages of each coil 111, 112. The processing unit 117 calculates the force acting on the wheel based on the calculated relative displacement of the target member 80 with respect to the sensor substrate 100.

[0046] When a lateral force acts on the wheel, the inclination of the central axis LCi of the inner ring member 60 with respect to the central axis of the outer ring member 50 increases. In this case, the axial distance between each coil 111, 112 and the target member 80 changes, and at least one of the output voltages of each coil 111, 112 changes. The processing unit 117 calculates the axial displacement based on the voltage signal input from the receiving circuit 114. The axial displacement is the relative displacement of the target member 80 in the axial direction with respect to the sensor substrate 100. Based on the calculated axial displacement, the processing unit 117 calculates the lateral force acting on the wheel.

[0047] On the other hand, when a vertical load is applied to the wheel, the central axis LSi of the inner ring member 60 is displaced in a direction perpendicular to the central axis of the outer ring member 50. As a result, the target member 80 fixed to the flange portion 62 is also displaced. In this case, the sensor board 100 is configured such that at least one of the output voltages of each coil 111, 112 changes. The processing unit 117 calculates the vertical displacement based on the voltage signal input from the receiving circuit 114. The vertical displacement is the relative displacement of the target member 80 with respect to the sensor board 100 in a direction perpendicular to the axial direction and the vehicle length direction. Based on the calculated vertical displacement, the processing unit 117 calculates the vertical load applied to the wheel.

[0048] The processing unit 117 calculates the rotation angle θm (i.e., the mechanical angle) of the wheel based on the output voltage of at least one of the first receiving coil 111 and the second receiving coil 112. The processing unit 117 then calculates the rotation speed of the wheel based on the calculated rotation angle θm. Specifically, for example, the processing unit 117 may calculate the rotation speed based on the time derivative of the rotation angle θm.

[0049] Figure 7 shows the procedure for the processing performed by the processing unit 117. The processing shown in Figure 7 is executed repeatedly at a predetermined cycle.

[0050] In step S10, a voltage signal is acquired from the receiving circuit 114. In step S11, the rotation angle θm is calculated based on the acquired voltage signal. In step S12, relative displacements such as axial displacement and vertical displacement are calculated based on the acquired voltage signal. In step S13, a correction process is performed to correct the calculated axial displacement and vertical displacement. In step S14, the lateral force is calculated based on the corrected axial displacement. The vertical load is calculated based on the corrected vertical displacement. The correction process will be described later.

[0051] Incidentally, the target member 80 may undergo thermal displacement due to temperature changes in the target member 80. For example, the heat generated in the brake device 20 may be transferred to the target member 80, causing its temperature to rise and potentially leading to thermal displacement. If thermal displacement occurs in the target member 80, there is a concern that the processing performed by the sensor board 100 will be affected by the thermal displacement, reducing the accuracy of the calculation of the force acting on the wheel.

[0052] Therefore, in this embodiment, the target member 80 and the sensor substrate 100 are equipped with a characteristic configuration for understanding the effect of thermal displacement of the target member 80. Below, the target member 80 will be described in detail with reference to Figures 3 to 5.

[0053] As shown in Figure 3, the target member 80 is divided into two parts in the circumferential direction. Specifically, the target member 80 is divided into two parts such that their circumferential lengths are equal. The target member 80 is divided to facilitate the assembly of the target member 80 to the hub bearing 40. For example, the target member 80 can be retrofitted to a finished hub bearing 40. Hereinafter, one of the divided parts of the target member 80 may be referred to as the first divided member 80A, and the other part as the second divided member 80B.

[0054] The target member 80 has a thermal displacement portion Rb and a fixed portion Ra. The thermal displacement portion Rb is a part in the circumferential direction. The fixed portion Ra is the part of the target member 80 other than the thermal displacement portion Rb and is the part that is fixed to the flange portion 62. The thermal displacement portion Rb is the part of the target member 80 that has a larger axial displacement due to temperature changes compared to the fixed portion Ra. In this case, the axial displacement per unit temperature change is taken as the amount of thermal displacement, and the amount of thermal displacement is made different between the thermal displacement portion Rb and the fixed portion Ra of the target member 80, making it possible to intentionally superimpose the effect of the thermal displacement of the target member 80 on the voltage signal detected by the sensor substrate 100. As a result, the voltage signal detected by the sensor substrate 100 can be made into a voltage signal that can grasp the effect of the thermal displacement of the target member 80. As a result, it is possible to reduce the effect of the thermal displacement of the target member 80 while suppressing the occurrence of inconveniences caused by the sensors being provided at multiple locations on the hub bearing.

[0055] In this embodiment, with θn being the phase indicating the circumferential position of the target member 80, the thermal displacement portion Rb is the portion of the second divided member 80B where 0°≦θn≦90°. The fixed portion Ra is the first divided member 80A and the portion of the second divided member 80B where 90°<θn≦180°. The first divided member 80A is the portion of the target member 80 where 180°≦θn≦360°.

[0056] As shown in Figures 4 and 5, each divided member 80A and 80B has a base portion 84A and 84B. Each base portion 84A and 84B extends in the circumferential direction and has thickness in the axial direction. Each base portion 84A and 84B is positioned adjacent to the flange portion 62 in the axial direction. In each divided member 80A and 80B, the detection recess 82 and the portion of the detection protrusion 81 that is closer to the flange portion 62 than the detection recess 82 in the axial direction constitute the base portion 84A and 84B.

[0057] Among the thermal displacement portions Rb, on the side opposite to the sensor substrate 100 in the axial direction, a back recess 86 that is recessed toward the side of the sensor substrate 100 in the axial direction is formed. The back recess 86 is formed by cutting out the base portion 84B. In FIG. 5, the back recess 86 is formed in the three detection recesses 82 in the portion of the second divided member 80B where 0° ≦ θn ≦ 90°. Each back recess 86 is formed across the radial direction in the thermal displacement portion Rb. That is, each back recess 86 is formed in a groove shape extending from the inner side to the outer side in the radial direction.

[0058] As shown in FIG. 8, in the back recess 86, the depth dimensions at both ends in the circumferential direction are larger than the depth dimension at the central portion in the circumferential direction. In the back recess 86, the depth dimension becomes larger from the central portion toward both ends in the circumferential direction. In other words, at the location where the back recess 86 is formed in the thermal displacement portion Rb, the thickness dimension of the base portion 84B is thinner at both ends in the circumferential direction than at the central portion in the circumferential direction. At the location where the back recess 86 is formed in the thermal displacement portion Rb, the thickness dimension of the base portion 84B becomes thicker from both ends toward the central portion in the circumferential direction.

[0059] That is, at the location where the back recess 86 is formed in the thermal displacement portion Rb, the central portion in the circumferential direction is the thick portion 88, and both ends in the circumferential direction are the thin portions 89. In FIG. 8, the thickness in the axial direction of the thick portion 88 is the thickest at LC, and the thickness in the axial direction of the thin portion 89 is the thinnest at LE (<LC). Thereby, at the location where the back recess 86 is formed in the thermal displacement portion Rb, the thickness of the base portion 84B is non-uniform in the circumferential direction.

[0060] Unlike the second divided member 80B, no back recess is formed in the first divided member 80A. For this reason, in the base portion 84A of the first divided member 80A, the thickness of the base portion 84B is uniform in the circumferential direction.

[0061] Figure 9 schematically shows the fixed portion Ra when the first divided member 80A undergoes thermal expansion, and Figure 10 schematically shows the thermally displaced portion Rb and fixed portion Ra when the second divided member 80B undergoes thermal expansion. In Figures 9 and 10, the position of the target member 80 when it undergoes thermal displacement is indicated by a dashed line, and the magnetic flux associated with the energization of the excitation coil 110 is indicated by a solid arrow.

[0062] As shown in Figure 9, in the first divided member 80A, since the thickness of the base portion 84A is uniform in the circumferential direction, thermal expansion occurs substantially uniformly with respect to the phase θn. In this case, the axial distance until the magnetic flux reaches the fixed portion Ra is similarly shortened by the amount of thermal expansion of the target member 80, regardless of the phase θn.

[0063] As shown in Figure 10, in the area of ​​the thermal displacement portion Rb where the back recess 86 is formed, the thickness of the base portion 84B is non-uniform in the circumferential direction, causing deformation of the second divided member 80B due to thermal expansion. Specifically, during thermal expansion, the thick portion 88 expands more in the axial direction than the thin portion 89. As a result, a moment load acts on the thermal displacement portion Rb of the second divided member 80B, causing the second divided member 80B to deform in the axial direction.

[0064] As shown in Figures 5 and 10, the portion of the second divided member 80B from the intermediate part (θn=90°) to the first end (θn=180°) in the circumferential direction is designated as the fixed portion Ra, which is fixed to the flange portion 62. In Figure 5, two parts of the fixed portion Ra are fixed to the flange portion 62 by bolts 83. The portion of the second divided member 80B from the intermediate part to the second end (θn=0°) opposite to the first end is designated as the thermal displacement portion Rb. Unlike the fixed portion Ra, the thermal displacement portion Rb is not fixed to the flange portion 62 by bolts, but is cantilevered relative to the fixed portion Ra. As a result, the second end of the thermal displacement portion Rb in the circumferential direction is designated as the free end.

[0065] In the configuration described above, when the fixed portion Ra of the second divided member 80B is fixed to the flange portion 62, the thermal displacement portion Rb of the second divided member 80B deforms so as to bend axially toward the sensor substrate 100 side relative to the flange portion 62. Due to the thermal expansion of the target member 80 and the axial bending of the second divided member 80B, a thermal displacement difference ΔL is generated between the thermal displacement portion Rb and the fixed portion Ra of the second divided member 80B. In this embodiment, the second divided member 80B deforms such that the thermal displacement difference between the thermal displacement portion Rb and the fixed portion Ra increases as the phase approaches from θn=90° to θn=0°. As a result, the amount of thermal displacement at the thermal displacement portion Rb can be made more precisely larger than that at the fixed portion Ra. The second divided member 80B corresponds to the "specific divided member".

[0066] In the thermal displacement portion Rb, the back-side recess 86 is formed on the opposite side in the axial direction from the surface on which the detection protrusion 81 and detection recess 82 are formed. This makes it possible to form the thermal displacement portion Rb on the second divided member 80B while avoiding the back-side recess 86 affecting the detected voltage signal.

[0067] In the thermal displacement section Rb, a back-side recess 86 is formed in each detection recess 82. This allows the thickness of the base section 84B to be reduced compared to a configuration in which the back-side recess 86 is formed in the detection protrusion 81, and makes it easier to deform the second divided member 80B in the axial direction. Furthermore, because the back-side recess 86 is formed over the radial direction, it is easier to deform the second divided member 80B in the axial direction compared to a configuration in which the back-side recess is formed only in a part of the radial direction.

[0068] Next, we will explain the correction process performed by the sensor board 100.

[0069] Figure 11 shows an example of the relationship between the axial displacement calculated in step S12 of Figure 7 and the rotation angle θm. In Figure 11, the axial displacement calculated based on the output voltages of each coil 111 and 112 is shown as the total displacement Xt. The total displacement Xt is superimposed with the unevenness displacement component Xa due to the uneven shape of the target member 80, the force displacement component Xf due to the force acting on the wheel, and the thermal displacement component Xh due to the thermal displacement of the target member 80. Here, it is assumed that the force acting on the wheel is constant and the temperature of the target member 80 is constant. Since the amount of thermal displacement is larger in the thermal displacement part Rb than in the fixed part Ra, the thermal displacement component Xh for the rotation angle θm corresponding to the thermal displacement part Rb is higher than the thermal displacement component Xh for the rotation angle θm corresponding to the fixed part Ra. In this embodiment, when the rotation angle θm = θa (0° ≤ θa ≤ 360°), the portion of the target member 80 with a phase θn = θa corresponds to the opposing portion facing each coil 111, 112.

[0070] The memory unit of the processing unit 117 stores unevenness displacement information, in which the rotation angle θm and the unevenness displacement component Xa are associated. Based on the total displacement Xt and rotation angle θm calculated based on the voltage signal, and the unevenness component information, the processing unit 117 removes the unevenness displacement component Xa from the calculated total displacement Xt and calculates the combined displacement component Xf+Xh of the force displacement component Xf and the thermal displacement component Xh.

[0071] Figure 12 shows an example of the progression of the summation displacement component Xf+Xh, which is calculated each time by the processing unit 117. The summation displacement component Xf+Xh increases to a value of X1 when the opposing portion of the target member 80 is the circumferential end (θn=0°) of the thermal displacement portion Rb. As the wheel rotates, the summation displacement component Xf+Xh gradually decreases from the increased value X1 as the amount of thermal displacement of the thermal displacement portion Rb decreases. When the opposing portion of the target member 80 is the fixed portion Ra, the summation displacement component Xf+Xh remains approximately constant at a normal value of X2.

[0072] The difference ΔX between the increased value X1 and the normal value X2 reflects only the thermal displacement component Xh among the components Xa, Xf, and Xh. Therefore, there is a correlation between the difference ΔX and the temperature T of the target member 80. Specifically, as shown in Figure 13, there is a correlation that the higher the temperature T of the target member 80, the larger the difference ΔX. The memory unit of the processing unit 117 stores temperature information that associates the difference ΔX with the temperature T of the target member 80. The processing unit 117 calculates the difference ΔX based on the calculated increased value X1 and the normal value X2. The processing unit 117 estimates the temperature T of the target member 80 based on the calculated difference ΔX and the temperature information.

[0073] The processing unit 117 corrects the calculated axial and vertical displacements based on the estimated temperature T of the target member 80. Specifically, the processing unit 117 removes the thermal displacement component Xh from the calculated sum of displacement components Xf+Xh based on the estimated temperature T of the target member 80, and extracts the force displacement component Xf.

[0074] Figure 14 shows the procedure for the correction process performed by the processing unit 117. The correction process is the same as step S13 in Figure 7.

[0075] In step S20, the unevenness displacement component Xa is removed from the total displacement Xt, and the summation displacement component Xf+Xh is extracted. As the total displacement Xt, the axial displacement value calculated in step S12 in Figure 7 can be used.

[0076] In step S21, it is determined whether the calculated sum of displacement components Xf+Xh, based on the rotation angle θm calculated in step S11 of Figure 7, is the value when the thermal displacement portion Rb of the target member 80 is the opposing portion. In this embodiment, it is determined whether the calculated rotation angle θm is 0°≦θm≦90°. If the determination in step S21 is positive, the process proceeds to step S22.

[0077] In step S22, a low-pass filter is performed. The reason for performing the low-pass filter is to use the summation displacement component Xf+Xh, which changes below a predetermined frequency, in the calculation of the difference ΔX. The thermal expansion of the target member 80 occurs very slowly compared to the relative displacement when a force is applied to the wheel. Therefore, by performing the low-pass filter, the influence of the force acting on the wheel on the calculation of the difference ΔX can be suppressed.

[0078] In step S23, the increment value X1 is updated. In this embodiment, if the summation displacement component Xf+Xh calculated in the current control cycle is greater than the current increment value X1, the summation displacement component Xf+Xh calculated in the current control cycle is stored in the memory unit of the processing unit 117 as the new increment value X1. This allows the maximum value of the summation displacement component Xf+Xh calculated when the thermal displacement component Rb is the opposing part to be used to estimate the temperature T of the target member 80.

[0079] The increased value X1 stored in the memory unit may be reset at predetermined intervals. For example, the increased value X1 may be reset each time the rotation angle θm reaches 360° from 0°. This allows the current total displacement component Xf+Xh to be stored in the memory unit as the increased value X1 even if the temperature of the target member 80 has decreased compared to the previous control cycle, and enables the update of the increased value X1 to be performed appropriately.

[0080] If a negative result is obtained in step S21, the process proceeds to step S24. In step S24, the same processing as in step S22 is performed. In step S25, the normal value X2 is updated. For example, the sum of displacement components Xf+Xh calculated for the current control cycle is stored in the memory unit of the processing unit 117 as the new normal value X2.

[0081] In step S26, the difference ΔX is calculated by subtracting the normal value X2 from the increased value X1. The increased value X1 and the normal value X2 can be values ​​stored in the memory unit of the processing unit 117. In step S27, the temperature T of the target member 80 is estimated based on the calculated difference ΔX and temperature information.

[0082] In step S28, the calculated axial and vertical displacements are corrected based on the estimated temperature T of the target member 80. In this embodiment, the thermal displacement component Xh is removed from the sum of the displacement components Xf + Xh based on the estimated temperature T of the target member 80. This extracts the force displacement component Xf from the sum of the displacement components Xf + Xh. Additionally, the thermal displacement component is removed from the vertical displacement calculated in step S12 of Figure 7 based on the estimated temperature T of the target member 80. This extracts the force displacement component from the vertical displacement.

[0083] For example, the memory unit of the processing unit 117 stores correction information that associates the temperature T of the target member 80 with the thermal displacement component Xh of the axial displacement. Based on the estimated temperature T of the target member 80 and the correction information, the processing unit 117 calculates the thermal displacement component Xh included in the calculated sum of displacement components Xf+Xh. The processing unit 117 extracts the force displacement component Xf by subtracting the thermal displacement component Xh from the calculated sum of displacement components Xf+Xh. The processing unit 117 performs the same processing for vertical displacement as for axial displacement to extract the force displacement component of vertical displacement.

[0084] After processing in step S28, the process proceeds to step S14 in Figure 7. In step S14, the lateral force is calculated based on the force displacement component Xf of the axial displacement calculated in step S28. The vertical load is calculated based on the force displacement component of the vertical displacement calculated in step S28.

[0085] In the above correction process, the temperature T of the target member 80 is estimated based on the difference ΔX between the axial displacement of the thermal displacement portion Rb and the axial displacement of the fixed portion Ra. Based on the estimated temperature T of the target member 80, the thermal displacement component is removed from the calculated axial displacement and vertical displacement. Therefore, the lateral force can be calculated based on the axial displacement from which the thermal displacement component Xh has been removed, and the influence of the thermal displacement of the target member 80 can be accurately reduced. Also, the vertical load can be calculated based on the vertical displacement from which the thermal displacement component has been removed, and the influence of the thermal displacement of the target member 80 can be accurately reduced.

[0086] <Modification Example of the First Embodiment> · The thermal displacement portion Rb of the target member 80 may have a shape different from that of the first embodiment. For example, as shown in FIG. 15, a back recess 186 may be formed in the thermal displacement portion Rb of the second divided member 80B. In the back recess 186, the depth dimension increases from both ends toward the central portion in the circumferential direction. That is, at the location where the back recess 186 is formed in the thermal displacement portion Rb, the center is a thin portion 188 in the circumferential direction, and both ends are thick portions 189 in the circumferential direction. The thickness of the thick portion 189 in the axial direction is the thickest at LE. The thickness of the thin portion 188 in the axial direction is the thinnest at LC (<LE). Even in this case, it is possible to deform the second divided member 80B in the axial direction and increase the amount of thermal displacement in the thermal displacement portion Rb of the second divided member 80B.

[0087] As shown in Figure 16, the hub bolt 17 is inserted through the bolt insertion hole 64 of the flange portion 62 in order to fix the wheel 11 to the flange portion 62. In this state, the head 17a of the hub bolt 17 may protrude inward in the vehicle width direction in the axial direction relative to the flange portion 62. In this case, a recessed portion may be formed on the outer side of the vehicle width direction in the axial direction of the target member 80 toward the detection projection 81 in order to avoid interference between the head 17a of the hub bolt 17 and the target member 80. Here, the thermal displacement portion Rb of the target member 80 may be formed using the recess to avoid interference between the head 17a of the hub bolt 17 and the target member 80.

[0088] As shown in Figure 17, a back-side recess 286 is formed in the thermal displacement portion Rb of the second divided member 80B. At the location where the back-side recess 286 is formed, a recessed space is formed in which the second divided member 80B covers the target member 80 side in both the circumferential and axial directions. The head 17a of the hub bolt 17 is positioned in the recessed space of the back-side recess 286. This avoids interference between the head 17a of the hub bolt 17 and the second divided member 80B. Furthermore, in the back-side recess 286, similar to the first embodiment, the thickness of the base portion 84B is made uneven in the circumferential direction. Therefore, the thermal displacement portion Rb can be formed while avoiding interference between the head 17a of the hub bolt 17 and the second divided member 80B.

[0089] In the thermal displacement section Rb, the back-side recess may be formed on each detection protrusion 81 instead of each detection recess 82. Also, in the thermal displacement section Rb, the back-side recess may be formed across adjacent detection protrusions 81 and detection recesses 82 in the circumferential direction.

[0090] The thermal displacement portion is not limited to the part of the second divided member 80B with a temperature of 0°≦θn≦90°, but may also be a portion of each divided member 80A, 80B determined by various phases θn. Two examples are described below. As the first example, the thermal displacement portion may be the part of the second divided member 80B with a temperature of 0°≦θn≦θa. In this case, the phase θa can be set in the range of 0°<θa≦180°. As the second example, the thermal displacement portion may be the part of each divided member 80A, 80B with a temperature of θb≦θn≦θc. In this case, each phase θb, θc can be set arbitrarily, for example, in the range of 0°≦θb<θc≦360°.

[0091] In the thermal displacement section Rb, the back-side recess is not limited to being formed in multiple locations; at least one is sufficient. For example, in Figure 5 above, a back-side recess 86 is formed in each of the three detection recesses 82 with a range of 0°≦θn≦90°. However, instead of this configuration, a back-side recess may be formed in only one or two of the three detection recesses 82 with a range of 0°≦θn≦90°. For example, a back-side recess may be formed only in the detection recess 82 near the phase θn=90° among the three detection recesses 82 with a range of 0°≦θn≦90°.

[0092] • It is not necessary to perform steps S22 and S24 in Figure 14 above.

[0093] <Second Embodiment> The second embodiment will be described below, focusing on the differences from the first embodiment, with reference to the drawings. In this embodiment, the configuration for differentiating the amount of thermal displacement between the thermal displacement portion Rb and the portion of the target member 80 other than the thermal displacement portion Rb has been changed.

[0094] As shown in Figure 18, the target member 80 is divided into three sections in the circumferential direction. Hereinafter, the section of the divided target member 80 that has the longest circumferential length will be referred to as the first section member 80X, the section that has the second longest circumferential length will be referred to as the second section member 80Y, and the section that has the shortest circumferential length will be referred to as the third section member 80Z. Each section member 80X, 80Y, and 80Z is fixed to the flange section 62 by bolts.

[0095] The third segmented member 80Z has a larger coefficient of thermal expansion than the first and second segmented members 80X and 80Y. Specifically, the third segmented member 80Z is made of a metal material with a larger coefficient of thermal expansion than the first and second segmented members 80X and 80Y. In this embodiment, the third segmented member 80Z is the thermally displaced part Rb. The first and second segmented members 80X and 80Y are made of the same metal material.

[0096] Figure 19 schematically shows the case when the second and third divided members 80Y and 80Z undergo thermal expansion. In Figure 19, the positions of the second and third divided members 80Y and 80Z when they undergo thermal displacement are indicated by dashed lines, and the magnetic flux associated with the energization of the excitation coil 110 is indicated by solid arrows.

[0097] In this embodiment, the axial distance until the magnetic flux reaches each divided member 80X, 80Y, and 80Z is shortened by the amount of thermal expansion of each divided member 80X, 80Y, and 80Z. In this case, because the thermal expansion coefficient of the third divided member 80Z is larger than that of the first and second divided members 80X and 80Y, a thermal displacement difference ΔL is generated between the first and second divided members 80X and 80Y and the third divided member 80Z. As a result, the axial distance until the magnetic flux reaches the third divided member 80Z is shorter than the axial distance until the magnetic flux reaches the first and second divided members 80X and 80Y. Therefore, without changing the shape of the target member 80 to form the thermal displacement area, the amount of axial thermal displacement in the thermal displacement area can be made larger than that of the part of the target member 80 other than the thermal displacement area.

[0098] <Modified form of the second embodiment> The third segmented member 80Z is not limited to being made of the same material. For example, only the portion of the third segmented member 80Z on the sensor substrate 100 side in the axial direction may be made of a metal material with a larger coefficient of thermal expansion than the first and second segmented members 80X and 80Y. In this case, the portion of the third segmented member 80Z on the flange portion 62 side in the axial direction may be made of the same metal material as the first and second segmented members 80X and 80Y. Even in this case, it is possible to create a difference in thermal displacement between the first and second segmented members 80X and 80Y and the third segmented member 80Z.

[0099] <Other Embodiments> Furthermore, each of the above embodiments may be implemented with the following modifications.

[0100] In the first and second embodiments, the number of divisions of the target member is not limited to those described above. In the first embodiment, it may be divided into, for example, three, four, or five or more parts (for example, equally divided in the circumferential direction). In the second embodiment, it may be divided into four or five or more parts. Also, the target member does not have to be divided. In a configuration with a small number of divisions of the target member, gaps in the circumferential direction can be avoided compared to a configuration with a large number of divisions of the target member, and noise superimposed on the voltage signal of the receiving coil can be suppressed.

[0101] The hub bearing is not limited to an inner ring rotating type; it may also be an outer ring rotating type. Specifically, the inner ring axis member (corresponding to the "first bearing member") constituting the outer ring rotating type hub bearing has an inner cylindrical portion (corresponding to the "first cylindrical portion") extending in the axial direction and is fixed to the knuckle 15. The outer ring axis member (corresponding to the "second bearing member") constituting the hub bearing has an outer cylindrical portion (corresponding to the "second cylindrical portion") provided on the outside of the inner cylindrical portion in the radial direction, and a flange portion that extends radially from the outer cylindrical portion and to which the wheel is fixed.

[0102] The sensor board and board mounting member are not limited to a structure in which they are fixed to the board mounting member at three points; they may also be fixed at one, two, or four or more points.

[0103] The sensor board 100 may be directly attached to the outer ring member 50 instead of the board mounting member 120.

[0104] The disc rotor is not limited to a ventilated disc; for example, it may be a solid disc consisting of a single circular disc.

[0105] In the above embodiment, a disc-type friction brake device was used as the braking device, but it is not limited to this. For example, the braking device may be a drum-type friction brake device instead of a disc-type friction brake device.

[0106] The processing unit may calculate only the axial displacement among the axial displacement and vertical displacement. In this case, the processing unit may calculate only the lateral force among the lateral force and vertical load.

[0107] The processing unit may directly calculate the force acting on the wheel based on the acquired voltage signal without calculating the relative displacement. In this case, the process in step S12 of Figure 7 above does not need to be performed. In step S13, the temperature of the target member 80 may be estimated based on the acquired voltage signal.

[0108] The mechanical devices to which the detection device is applied are not limited to wheel units, but may also include, for example, an aircraft equipped with a propeller as a rotating body, a ship equipped with a screw as a rotating body, an internal combustion engine equipped with a crankshaft as a rotating body, or a generator equipped with a turbine as a rotating body.

[0109] Furthermore, the rotating body is not limited to those used with its axis of rotation in a horizontal direction; it may also be used with its axis of rotation in a direction other than horizontal (for example, vertical).

[0110] The control devices and methods described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control devices and methods described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control devices and methods described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium. [Explanation of Symbols]

[0111] 10...Wheel unit (mechanical device), 15...Knuckle (base part), 40...Hub bearing, 80...Target member (detection target part), 100...Sensor board (signal output part).

Claims

1. In a detection device applied to a mechanical device (10), The aforementioned mechanical device is A solid of revolution (11, 14) and, A hub bearing (40) rotatably supports the rotating body with respect to the base portion (15), Equipped with, The aforementioned hub bearing is The hub bearing has a first cylindrical portion (51) that extends in the axial direction, which is the direction in which the rotational axis of the hub bearing extends, and a first bearing portion (50) that is fixed to the base portion, It has a second cylindrical portion (61) provided at a position opposite the first cylindrical portion in the radial direction perpendicular to the axial direction, and a second bearing portion (60) to which the rotating body is fixed, A rolling element (41) is provided between the first bearing portion and the second bearing portion, It has the following features, and the second bearing portion is rotatably supported with respect to the base portion, A circular detection target portion (80) is fixed to the second bearing portion and extends in the circumferential direction of the second bearing portion with respect to the rotation center of the second bearing portion, A signal output unit (100) is provided at a position opposite to the detection target unit in the axial direction, Equipped with, The signal output unit outputs a voltage signal that changes according to the relative displacement of the detection target unit with respect to the signal output unit. A portion of the detection target in the circumferential direction is defined as a thermally displaced portion (Rb), The detection device wherein the thermal displacement portion is a portion of the detection target portion in which the amount of thermal displacement in the axial direction due to temperature changes in the detection target portion is larger than that of the portion (Ra) other than the thermal displacement portion.

2. The detection target unit is configured such that detection recesses and detection protrusions that project toward the signal output unit in the axial direction relative to the detection recesses are alternately provided in the circumferential direction. The detection device according to claim 1, wherein, of the thermal displacement portion, a back recess (86, 186, 286) is formed on the side opposite to the signal output portion in the axial direction, which is recessed toward the signal output portion in the axial direction.

3. The detection device according to claim 2, wherein the back side recess is formed in at least one of the detection recesses provided in the thermal displacement portion.

4. The detection device according to claim 2 or 3, wherein the depth dimensions of the recesses on the back side at both ends in the circumferential direction are greater than the depth dimension of the central part in the circumferential direction.

5. The detection device according to claim 2 or 3, wherein the recess on the back side is formed in the thermal displacement portion over the radial direction.

6. The second bearing portion has a flange portion (62) that extends radially from the second cylindrical portion and to which the rotating body is fixed. The detection target section (80A, 80B) is formed in an annular shape by combining a plurality of segmented members that extend in the circumferential direction. At least one of the plurality of divided members is a specific divided member (80B) having the thermal displacement portion, At least a predetermined portion of the specified divided member from the middle portion to the first end in the circumferential direction is a fixed portion (Ra) that is fixed to the flange portion. The detection device according to claim 2 or 3, wherein the portion of the specific divided member from the intermediate portion to the second end opposite to the first end is cantilevered with respect to the fixed portion and is the thermal displacement portion.

7. The flange portion is formed with bolt insertion holes (64) through which hub bolts (17) for fixing the rotating body are inserted. When the hub bolt is inserted through the bolt insertion hole, its head (17a) protrudes from the flange portion toward the side of the detection target portion in the axial direction. The detection device according to claim 6, wherein the head of the hub bolt is positioned in the recessed space of the rear recess.

8. The detection device according to claim 1, wherein the thermal displacement portion has a greater coefficient of thermal expansion than the portion of the detection target other than the thermal displacement portion.

9. The processing unit (117) is included, The aforementioned processing unit, A process to calculate the relative displacement based on the output voltage signal, A process to estimate the temperature of the detection target based on the difference between the relative displacement of the thermal displacement part and the relative displacement of the part of the detection target other than the thermal displacement part, among the calculated relative displacements, Based on the estimated temperature, a process is performed to correct the calculated relative displacement so as to remove the effect of thermal displacement of the detected part from the calculated relative displacement, A process for calculating the force acting on the rotating body based on the corrected relative displacement, A detection device according to any one of claims 1 to 3, 8, which performs the following:

10. In a detection device applied to a mechanical device (10), The aforementioned mechanical device is A solid of revolution (11, 14) and, A hub bearing (40) rotatably supports the rotating body with respect to the base portion (15), Equipped with, The aforementioned hub bearing is The hub bearing has a first cylindrical portion (51) that extends in the axial direction, which is the direction in which the rotational axis of the hub bearing extends, and a first bearing portion (50) that is fixed to the base portion, It has a second cylindrical portion (61) provided at a position opposite the first cylindrical portion in the radial direction perpendicular to the axial direction, and a second bearing portion (60) to which the rotating body is fixed, A rolling element (41) is provided between the first bearing portion and the second bearing portion, It has the following features, and the second bearing portion is rotatably supported with respect to the base portion, A circular detection target portion (80) is fixed to the second bearing portion and extends in the circumferential direction of the second bearing portion with respect to the rotation center of the second bearing portion, A signal output unit (100) is provided at a position opposite to the detection target unit in the axial direction, Equipped with, The signal output unit outputs a voltage signal that changes according to the relative displacement of the detection target unit with respect to the signal output unit. A portion of the detection target in the circumferential direction is defined as a thermally displaced portion (Rb), The thermal displacement portion is a portion of the detection target portion in which the amount of thermal displacement in the axial direction due to temperature changes in the detection target portion is larger than that of the portion other than the thermal displacement portion (Ra). Computer (117), A process to calculate the relative displacement based on the output voltage signal, A process to estimate the temperature of the detection target based on the difference between the relative displacement of the thermal displacement part and the relative displacement of the part of the detection target other than the thermal displacement part, among the calculated relative displacements, Based on the estimated temperature, a process is performed to correct the calculated relative displacement so as to remove the effect of thermal displacement of the detected part from the calculated relative displacement, A process for calculating the force acting on the rotating body based on the corrected relative displacement, A program that executes something.

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