Bearing device

Abstract

To provide a bearing device having a generator with large power generation amount.SOLUTION: A bearing device is equipped with a rolling bearing that has an inner ring, an outer ring, and a rolling element, and a generator that generates power with relative rotations of the inner ring with respect to the outer ring. The inner ring has an inner ring outer diameter surface. The outer ring has an outer ring inner diameter surface. The outer ring is disposed on the outer side in a diametrical direction of the inner ring so that the outer ring inner diameter surface opposes the inner ring outer diameter surface. The rolling element is disposed between the inner ring outer diameter surface and the outer ring inner diameter surface. The generator has a magnetic ring, and a stator. The magnetic ring has a multipolar magnet in which N-poles and S-poles are alternately magnetized in a circumferential direction, and is attached to one of the inner ring and the outer ring.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a bearing device. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2020-148676 (Patent Document 1) describes a sensor-equipped bearing (bearing device). The bearing device described in Patent Document 1 includes a rolling bearing, an encoder magnet, a cover, and a coil substrate. The rolling bearing includes an inner ring, an outer ring, and rolling elements.

[0003] The direction of the central axis of the inner ring is defined as the axial direction, the direction passing through the central axis and perpendicular to the central axis is defined as the radial direction, and the direction along the circumference of a circle centered on the central axis is defined as the circumferential direction.

[0004] The inner ring has an inner ring outer diameter surface. The inner ring outer diameter surface extends in the circumferential direction. The outer ring has an outer ring inner diameter surface. The outer ring inner diameter surface extends in the circumferential direction. The outer ring is arranged outside the inner ring such that the outer ring inner diameter surface faces the inner ring outer diameter surface with a gap between them in the radial direction. The rolling elements are arranged between the inner ring outer diameter surface and the outer ring inner diameter surface. The inner ring is a rotating ring, and the outer ring is a stationary ring. In other words, the inner ring rotates relative to the outer ring.

[0005] The encoder magnet has a substrate and a magnetic track. The substrate is annular and extends in the circumferential direction. The magnetic track is disposed on a main surface of the substrate. The magnetic track is magnetized with alternating north and south poles in the circumferential direction. The cover is annular and extends in the circumferential direction. The cover is attached to the outer ring so as to face the magnetic track with a gap in the axial direction.

[0006] The coil substrate is disposed inside the cover. The coil substrate has a partial arc shape extending in the circumferential direction. A yoke and a coil pattern are formed on the coil substrate. The yokes are arranged at intervals in the circumferential direction. The coil pattern extends in the circumferential direction so as to meander around the yoke. The coil substrate is attached to the cover so as to face the magnetic track at an interval in the axial direction.

[0007] In the bearing device described in Patent Document 1, a change in magnetic flux from the magnetic track caused by relative rotation of the inner ring with respect to the outer ring generates an induced electromotive force in the coil pattern, thereby generating electricity. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-148676 Summary of the Invention [Problem to be solved by the invention]

[0009] In the bearing device described in Patent Document 1, the coil pattern on the coil substrate is used as the coil, and the coil patterns formed in multiple layers are connected in parallel or series, but since there is a limit to the number of layers on which the coil patterns can be stacked, there is room for improvement in the amount of power generation (generated voltage).

[0010] The present invention has been made in view of the above-mentioned problems of the prior art. More specifically, the present invention provides a bearing device having a generator that generates a large amount of electricity. [Means for solving the problem]

[0011] The bearing device of the present invention includes a rolling bearing having an inner ring, an outer ring, and rolling elements, and a generator that generates electricity in response to relative rotation of the inner ring with respect to the outer ring. The inner ring has an inner ring outer diameter surface. The outer ring has an outer ring inner diameter surface. The outer ring is disposed radially outward of the inner ring so that the outer ring inner diameter surface faces the inner ring outer diameter surface. The rolling elements are disposed between the inner ring outer diameter surface and the outer ring inner diameter surface. The generator includes a magnetic ring and a stator. The magnetic ring has a multi-pole magnet with N poles and S poles magnetized alternately in the circumferential direction, and is attached to one of the inner ring and the outer ring. The stator includes an outer ring, multiple pins, and a coil. The outer ring has an annular portion extending circumferentially, and is attached to the other of the inner ring and the outer ring. The annular portion has a facing surface that faces the magnetic ring with a gap in the axial direction. The multiple pins are attached to the annular portion so that they are lined up with a gap in the circumferential direction. Each of the pins protrudes axially from the opposing surface toward the magnetic ring. The outer ring and the pins are made of a magnetic material. A coil is wound around each of the pins.

[0012] The bearing device may further include a sensor, a wireless communication circuit that wirelessly transmits an output of the sensor, a power supply circuit that rectifies the output of the generator to generate power to be supplied to the sensor and the wireless communication circuit, and a circuit board. The sensor, wireless communication circuit, and power supply circuit may be mounted on the circuit board. The circuit board may be arranged on an opposing surface to avoid the multiple pins.

[0013] In the bearing device described above, a plurality of holes may be formed in the annular portion, and the plurality of pins may be attached to the annular portion by being fitted into the plurality of holes, respectively.

[0014] In the above-mentioned bearing device, the axial distance between the tip of the pin and the opposing surface may be 10 times or more the axial distance between the multi-pole magnet and the tip of the pin. In the above-mentioned bearing device, the circuit board may be mounted with a plurality of electrical components constituting a sensor, a wireless communication circuit, and a power supply circuit. The tip of each of the plurality of pins may be located axially farther from the opposing surface than any of the plurality of electrical components.

[0015] In the above bearing device, the magnetic ring and the outer ring may be attached to the inner ring and the outer ring, respectively. The inner ring may have a first end face which is the end face of the inner ring in the axial direction, and an inner ring inner diameter surface. An end of the first end face on the inner ring inner diameter surface side may have a first exposed area which is annular and extends circumferentially and is exposed from the outer ring. The outer ring may have a second end face which is the end face of the outer ring in the axial direction, and an outer ring outer diameter surface. An end of the second end face on the outer ring outer diameter surface side may have a second exposed area which is annular and extends circumferentially and is exposed from the outer ring.

[0016] In the bearing device, the magnetic ring and the outer ring may be attached to the inner ring and the outer ring, respectively. There may be a gap between the magnetic ring and the outer ring that is continuous in the circumferential direction. [Effects of the Invention]

[0017] The bearing device of the present invention can increase the amount of power generated by the generator. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a perspective view of the bearing device 100. [Figure 2] FIG. 2 is a front view of the bearing device 100. [Figure 3] FIG. 2 is a cross-sectional view of the bearing device 100. [Figure 4] FIG. 2 is an exploded perspective view of the bearing device 100. [Figure 5] 2 is a schematic cross-sectional view of the bearing device 100, in which the magnetic ring 30 and the stator 40 are linearly developed. FIG. [Figure 6] 1 is a perspective view of a bearing device 100 in which the rolling bearing 10 and the magnetic ring 30 are not shown. [Figure 7] 1 is a cross-sectional view showing an example of use of the bearing device 100. FIG. [Figure 8] 10 is a schematic cross-sectional view of a magnetic ring 30 and a stator 40 in a bearing device 100 according to a modified example, which are linearly developed. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] The details of the embodiment will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and redundant explanations will not be repeated. The bearing device according to the embodiment is referred to as bearing device 100.

[0020] (Configuration of bearing device 100) The configuration of the bearing device 100 will be described below.

[0021] FIG. 1 is a perspective view of the bearing device 100. FIG. 2 is a front view of the bearing device 100. FIG. 3 is a cross-sectional view of the bearing device 100. FIG. 3 shows a cross section including the central axis A. FIG. 4 is an exploded perspective view of the bearing device 100. As shown in FIGS. 1, 2, 3, and 4, the bearing device 100 has a rolling bearing 10 and a generator 20. The generator 20 has a magnetic ring 30 and a stator 40. The bearing device 100 may further have a circuit board 50.

[0022] The rolling bearing 10 has an inner ring 11, an outer ring 12, a plurality of rolling elements 13, a cage 14, and a seal 15. The rolling bearing 10 is, for example, a deep groove ball bearing. However, the rolling bearing 10 is not limited to this.

[0023] The central axis of inner ring 11 is defined as central axis A. The direction of central axis A is defined as the axial direction. The direction passing through central axis A and perpendicular to central axis A is defined as the radial direction. The direction along the circumference of a circle centered on central axis A is defined as the circumferential direction. Inner ring 11 has end face 11a, end face 11b (first end face), inner diameter surface 11c (inner ring inner diameter surface), and outer diameter surface 11d (inner ring outer diameter surface).

[0024] End face 11a and end face 11b are end faces of inner ring 11 in the axial direction. End face 11a is on one side in the axial direction (the left side in FIG. 1). End face 11b is the surface opposite end face 11a in the axial direction. In other words, end face 11b is on the other side in the axial direction (the right side in FIG. 1).

[0025] The inner diameter surface 11c extends in the circumferential direction. The inner diameter surface 11c faces the central axis A. One end and the other end of the inner diameter surface 11c in the axial direction are connected to the end surface 11a and the end surface 11b, respectively. The outer diameter surface 11d extends in the circumferential direction. The outer diameter surface 11d faces the opposite side from the central axis A. In other words, the outer diameter surface 11d is the opposite surface of the inner diameter surface 11c in the radial direction. One end and the other end of the outer diameter surface 11d in the axial direction are connected to the end surface 11a and the end surface 11b, respectively.

[0026] The outer diameter surface 11d has a raceway surface 11da. The raceway surface 11da is the portion of the outer diameter surface 11d that comes into contact with the rolling elements 13. The raceway surface 11da extends in the circumferential direction. The raceway surface 11da is located at the center of the outer diameter surface 11d in the axial direction. In a cross section perpendicular to the circumferential direction, the raceway surface 11da has a partial arc shape.

[0027] The outer diameter surface 11d has a groove 11db. The groove 11db is located at the end of the outer diameter surface 11d on the side of the end face 11b. The groove 11db extends in the circumferential direction.

[0028] The outer ring 12 has an end face 12a, an end face 12b (second end face), an inner diameter surface 12c (outer ring inner diameter surface), and an outer diameter surface 12d (outer ring outer diameter surface). The end faces 12a and 12b are end faces of the outer ring 12 in the axial direction. The end face 12a is on one side in the axial direction. The end face 12b is the surface opposite to the end face 12a in the axial direction. In other words, the end face 12b is on the other side in the axial direction.

[0029] The inner diameter surface 12c extends in the circumferential direction. The inner diameter surface 12c faces the central axis A. One end and the other end of the inner diameter surface 12c in the axial direction are continuous with the end face 12a and the end face 12b, respectively. The outer ring 12 is disposed outside the inner ring 11 so that the inner diameter surface 12c faces the outer diameter surface 11d with a gap therebetween. The outer diameter surface 12d extends in the circumferential direction. The outer diameter surface 12d faces the opposite side from the central axis A. In other words, the outer diameter surface 12d is the opposite surface of the inner diameter surface 12c in the radial direction. One end and the other end of the outer diameter surface 12d in the axial direction are continuous with the end face 12a and the end face 12b, respectively.

[0030] The inner diameter surface 12c has a raceway surface 12ca. The raceway surface 12ca is the portion of the inner diameter surface 12c that comes into contact with the rolling elements 13. The raceway surface 12ca extends in the circumferential direction. The raceway surface 12ca is located at the center of the inner diameter surface 12c in the axial direction. In a cross section perpendicular to the circumferential direction, the raceway surface 12ca has a partial arc shape.

[0031] The inner diameter surface 12c has grooves 12cb and 12cc. Groove 12cb is located at the end of the inner diameter surface 12c on the end face 12a side. Groove 12cb extends in the circumferential direction. Groove 12cb is located between the raceway surface 12ca and the end face 12a in the axial direction. Groove 12cc is located at the end of the inner diameter surface 12c on the end face 12b side. Groove 12cc extends in the circumferential direction.

[0032] The rolling elements 13 are spherical. The rolling elements 13 are arranged between the outer diameter surface 11d and the inner diameter surface 12c. More specifically, the rolling elements 13 are arranged between the raceway surface 11da and the raceway surface 12ca. The multiple rolling elements 13 are arranged at intervals in the circumferential direction. The cage 14 is arranged between the outer diameter surface 11d and the inner diameter surface 12c. The cage 14 holds the multiple rolling elements 13 so that the interval between two adjacent rolling elements 13 is within a certain range. The portion of the cage 14 that holds the rolling elements 13 is connected on the other side in the axial direction and is open on one side in the axial direction.

[0033] The seal 15 is annular and extends in the circumferential direction. The outer peripheral edge of the seal 15 is inserted into the groove 12cb. The inner peripheral edge of the seal 15 is in contact with a seal groove 11dc formed in the outer diameter surface 11d. The inner peripheral edge of the seal 15 may face the seal groove 11dc with a gap therebetween. The space between the outer diameter surface 11d and the inner diameter surface 12c is called a bearing space. One axial side of the bearing space is closed by the seal 15. A lubricant is sealed in the bearing space.

[0034] The magnetic ring 30 has a core 31 and a multi-pole magnet 32. The core 31 has a cylindrical portion 31a and an annular portion 31b. The cylindrical portion 31a is cylindrical and extends in the axial direction. The cylindrical portion 31a is fitted into a groove 11db on its inner diameter surface. This allows the core 31 (magnetic ring 30) to be attached to the inner ring 11. The annular portion 31b is annular and extends in the circumferential direction. The annular portion 31b protrudes radially outward from one axial end of the cylindrical portion 31a.

[0035] The multi-pole magnet 32 ​​is disposed on the surface of the annular portion 31b facing the other side in the axial direction. The multi-pole magnet 32 ​​is formed, for example, from rubber mixed with magnetic powder. The multi-pole magnet 32 ​​is vulcanization-bonded to the annular portion 31b. The multi-pole magnet 32 ​​is magnetized with alternating north and south poles in the circumferential direction.

[0036] The stator 40 includes an outer ring 41, a plurality of pins 42, a bobbin 43, and a coil 44. The outer ring 41 is made of a magnetic material such as silicon steel, carbon steel, martensitic stainless steel, or ferritic stainless steel.

[0037] The outer ring 41 has an annular portion 41a, a cylindrical portion 41b, and a cylindrical portion 41c. The annular portion 41a is annular and extends in the circumferential direction. The cylindrical portion 41b is cylindrical and extends from the radially inner end of the annular portion 41a to one side in the axial direction. The cylindrical portion 41b faces the magnetic ring 30 in the axial direction, for example. It is preferable that there is a gap between the cylindrical portion 41b and the magnetic ring 30. This gap is continuous in the circumferential direction. The cylindrical portion 41b may face the end face 11b. In this case, there is a gap between the cylindrical portion 41b and the end face 11b that is continuous in the circumferential direction. This gap is, for example, 1 mm or less. The cylindrical portion 41c is cylindrical and extends from the radially outer end of the annular portion 41a to one side in the axial direction. The cylindrical portion 41c is fitted into the groove 12cc on its outer diameter surface. As a result, the outer ring 41 (stator 40 ) is attached to the outer ring 12 .

[0038] The annular portion 41a has a first surface 41aa (opposing surface) and a second surface 41ab. The first surface 41aa and the second surface 41ab are end surfaces of the annular portion 41a in the axial direction. The first surface 41aa faces one side in the axial direction. The first surface 41aa faces the magnetic ring 30 (multi-pole magnet 32) with a gap in the axial direction. The second surface 41ab faces the other side in the axial direction. In other words, the second surface 41ab is the surface opposite the first surface 41aa in the axial direction.

[0039] A plurality of holes 41ac are formed in the annular portion 41a. The holes 41ac penetrate the annular portion 41a in the thickness direction (i.e., the axial direction). The plurality of holes 41ac are arranged at intervals in the circumferential direction. Note that the holes 41ac do not have to penetrate the annular portion 41a as long as they can receive pins 42 (described later).

[0040] The outer diameter of the outer ring 41 (the outer diameter of the cylindrical portion 41c) is preferably smaller than the outer diameter of the outer ring 12. Furthermore, the inner diameter of the outer ring 41 (the inner diameter of the cylindrical portion 41b) is preferably larger than the inner diameter of the inner ring 11. Therefore, an end of the end face 11b on the inner diameter surface 11c side has an annular region (first exposed region) extending circumferentially and exposed from the outer ring 41, and an end of the end face 12b on the outer diameter surface 12d side has an annular region (second exposed region) extending circumferentially and exposed from the outer ring 41.

[0041] The pins 42 are made of a magnetic material. For example, the pins 42 are made of silicon steel, carbon steel, martensitic stainless steel, ferritic stainless steel, or the like. The pins 42 may be made of the same material as the outer ring 41, or may be made of a different material from the outer ring 41. The pins 42 are, for example, cylindrical. The pins 42 may also be prismatic. The pitch between two adjacent pins 42 is, for example, equal to the pitch between two adjacent magnetic poles of the multi-pole magnet 32.

[0042] The pins 42 are attached to the annular portion 41a so as to be spaced apart in the circumferential direction. The pins 42 are preferably attached to the annular portion 41a by being fitted into holes 41ac. The pins 42 may be attached to the annular portion 41a by press-fitting, bonding, laser welding, or a combination of these. The pins 42 protrude in the axial direction from the first surface 41aa toward the magnetic ring 30 (multi-pole magnet 32). The tips of the pins 42 are spaced apart from the magnetic ring 30 (multi-pole magnet 32) in the axial direction.

[0043] A bobbin 43 is passed through the pin 42. A coil 44 is wound around the outer circumferential groove of the bobbin 43. The coil 44 may be wound directly around the pin 42 without using the bobbin 43. It is preferable that the coil 44 is wound around the pin 42 multiple times. The winding direction of the coil 44 around one pin 42 is opposite to the winding direction of the coil 44 around another pin 42 adjacent to the one pin 42 in the circumferential direction. The coils 44 wound around each of the multiple pins 42 are connected in series or in parallel.

[0044] The axial distance between the tip of pin 42 and first surface 41aa is defined as a first distance. The axial distance between the tip of pin 42 and multi-pole magnet 32 ​​is defined as a second distance. The first distance is preferably 10 times or more the second distance.

[0045] 5 is a schematic cross-sectional view of the magnetic ring 30 and stator 40 of the bearing device 100, linearly developed. As shown in FIG. 5, magnetic flux (see arrows in FIG. 5) emitted from the north pole of the multi-pole magnet 32 ​​enters the outer ring 41 (annular portion 41a) from one pin 42, passes through another pin 42 adjacent to the pin 42 in the circumferential direction, and returns to the south pole of the multi-pole magnet 32. As the magnetic ring 30 rotates, the positions of the north and south poles of the multi-pole magnet 32 ​​are swapped, and the direction of the magnetic flux is reversed. The alternating magnetic field generated in this way generates an alternating voltage between both ends of the coil 44.

[0046] 1, 2, 3, and 4, the circuit board 50 is disposed on the first surface 41aa. The circuit board 50 is disposed so as to avoid the plurality of pins 42. From another perspective, the circuit board 50 is positioned so as not to overlap the plurality of pins 42 when viewed in the axial direction. An insulating sheet (not shown) may be disposed between the circuit board 50 and the first surface 41aa. The circuit board 50 is attached to the annular portion 41a using, for example, screws, adhesive, or the like.

[0047] Fig. 6 is a perspective view of the bearing device 100, with the rolling bearing 10 and magnetic ring 30 not shown. As shown in Fig. 6, the circuit board 50 has a terminal 50a and a terminal 50b. One end and the other end of the coil 44 are connected to the terminal 50a and the terminal 50b, respectively. A power supply circuit 51, a sensor 52, and a wireless communication circuit 53 are mounted on the circuit board 50.

[0048] The power supply circuit 51 is connected to terminals 50a and 50b by wiring (not shown) formed on the circuit board 50. The output (AC) of the generator 20 (coil 44) is rectified in the power supply circuit 51 to become DC power. The power supply circuit 51 is connected to the sensor 52 and the wireless communication circuit 53 by wiring (not shown) formed on the circuit board 50. This supplies the DC power to the sensor 52 and the wireless communication circuit 53, driving them.

[0049] The sensor 52 monitors the condition of the rolling bearing 10. There may be, for example, a plurality of sensors 52. In the example shown in FIG. 5, the sensors 52 are an acceleration sensor 52a and a temperature sensor 52b. The sensors 52 (acceleration sensor 52a, temperature sensor 52b) are connected to the wireless communication circuit 53 by wiring (not shown) formed on the circuit board 50. As a result, the outputs of the sensors 52 (acceleration sensor 52a, temperature sensor 52b) are transmitted to the wireless communication circuit 53. The wireless communication circuit 53 wirelessly transmits the outputs from the sensors 52 from an antenna (not shown).

[0050] The tip of the pin 42 is located farther from the first surface 41aa than any of the electrical components that make up the power supply circuit 51, the sensor 52, and the wireless communication circuit 53. From another perspective, the height of the pin 42 is greater than the maximum height of the electrical components that make up the power supply circuit 51, the sensor 52, and the wireless communication circuit 53.

[0051] Although not shown, a resin material or the like may be applied to the surface of the circuit board 50 in order to protect the surface. Furthermore, although not shown, a sealing material made of a resin material may be filled into the internal space of the outer ring 41 in order to protect the surface of the circuit board 50. The filling height of this sealing material is set to the height of the cylindrical portion 41b.

[0052] FIG. 7 is a cross-sectional view showing an example of use of bearing device 100. FIG. 7 shows a cross section including central axis A. As shown in FIG. 7, shaft 110 has end 110a. End 110a is the end of shaft 110 on the other side in the axial direction (the right side in FIG. 7). The outer diameter of end 110a is smaller than the outer diameter of the portion of shaft 110 that is connected to end 110a. In other words, a step is formed on the outer diameter surface of shaft 110 between end 110a and the portion of shaft 110 that is connected to end 110a.

[0053] The inner diameter surface 11c is fitted onto the outer diameter surface of the end portion 110a so that the end surface 11a contacts this step. A nut 111 and a spacer 112 are attached to the end portion 110a. The nut 111 is threadedly engaged with the end portion 110a. The spacer 112 is disposed between the nut 111 and the inner ring 11, and contacts the first exposed region of the end surface 11b. In this way, the inner ring 11 is attached to the shaft 110.

[0054] The housing 120 has an end 120a. The end 120a is the end of the housing 120 on the other side in the axial direction. The inner diameter of the end 120a is larger than the inner diameter of the portion of the housing 120 that is continuous with the end 120a. In other words, a step is formed on the inner diameter surface of the housing 120 between the end 120a and the portion of the housing 120 that is continuous with the end 120a.

[0055] The outer diameter surface 12d is fitted to the inner diameter surface of the end portion 120a so that the end surface 12a contacts this step. A lid 121 is attached to the other axial end portion of the housing 120. The lid 121 contacts the second exposed region of the end surface 12b. In this way, the outer ring 12 is attached to the housing 120.

[0056] (Effects of bearing device 100) The effects of the bearing device 100 will be described below.

[0057] In the bearing device 100, the outer ring 41 not only attaches the stator 40 to the rolling bearing 10, but also functions as part of the yoke of the stator 40. Therefore, the bearing device 100 does not require a separate part for fixing the stator 40, making it possible to reduce the number of parts and make the device more compact.

[0058] In the bearing device 100, the pin 42 is attached to the annular portion 41a by fitting into the hole 41ac, which facilitates positioning for attaching the pin 42. Furthermore, no jig is required for attaching the pin 42, which improves the efficiency of the work of attaching the pin 42.

[0059] In the bearing device 100, the first distance is ten or more times the second distance, so that the magnetic flux from the multi-pole magnet 32 ​​is less likely to leak to the first surface 41aa. Therefore, the bearing device 100 reduces leakage magnetic flux and makes it possible to increase the power generation voltage of the generator 20. As a result, the circuit board 50 (power supply circuit 51, sensor 52, wireless communication circuit 53) can be driven stably even in a low-speed rotation region where the rotation speed of the inner ring 11 is low.

[0060] In the bearing device 100, the tip of the pin 42 is located farther from the first surface 41aa than any of the electrical components that make up the power supply circuit 51, the sensor 52, and the wireless communication circuit 53, thereby avoiding contact between the magnetic ring 30 and the electrical components.

[0061] In the bearing device 100, the inner ring 11 can be attached to the shaft 110 with the nut 111 and spacer 112 using the first exposed area of ​​the end face 11b, and the outer ring 12 can be attached to the housing 120 with the lid 121 using the second exposed area of ​​the end face 12b, so that the bearing device 100 can be used without changing the structures of the shaft 110 and the housing 120. Furthermore, because the bearing device 100 is attached to the shaft 110 and the housing 120 as described above, it can be attached compactly in the axial direction.

[0062] In the bearing device 100, there is a gap between the cylindrical portion 41b and the magnetic ring 30 (or between the cylindrical portion 41b and the end face 11b), so that radio waves from the antenna of the wireless communication circuit 53 can be emitted to the outside through the gap.

[0063] (Variation 1) Fig. 8 is a schematic cross-sectional view of the magnetic ring 30 and the stator 40 in a bearing device 100 according to a modified example, linearly developed. As shown in Fig. 8, the pitch between two adjacent pins 42 may be larger than the pitch between two adjacent magnetic poles of the multi-pole magnet 32. This makes it possible to accommodate an increase in the number of magnetic poles magnetized in the multi-pole magnet 32.

[0064] (Variation 2) A hole 41ad (not shown) may be formed in the annular portion 41a. The hole 41ad is located opposite the antenna of the wireless communication circuit 53. This allows radio waves from the antenna of the wireless communication circuit 53 to be emitted to the outside through the hole 41ad. The hole 41ad may be plugged with a non-metallic material (for example, a resin material).

[0065] The gap between the cylindrical portion 41b and the magnetic ring 30 (or between the cylindrical portion 41b and the end face 11b) has a labyrinth seal structure, which can prevent foreign matter from entering the inside of the generator 20. Although not shown, in order to prevent foreign matter from entering the inside of the generator 20, the gap between the cylindrical portion 41b and the magnetic ring 30 (or between the cylindrical portion 41b and the end face 11b) may be sealed with a rubber material or the like.

[0066] Although the embodiments of the present invention have been described above, the above-described embodiments can be modified in various ways. Furthermore, the scope of the present invention is not limited to the above-described embodiments. The scope of the present invention is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0067] 10 rolling bearing, 11 inner ring, 11a, 11b end face, 11c inner diameter surface, 11d outer diameter surface, 11da raceway surface, 11db groove, 11dc seal groove, 12 outer ring, 12a, 12b end face, 12c inner diameter surface, 12ca raceway surface, 12cb, 12cc groove, 12d outer diameter surface, 13 rolling element, 14 cage, 15 seal, 20 generator, 30 magnetic ring, 31 core, 31a cylindrical portion, 31b annular portion, 32 multi-pole magnet, 40 stator, 41 outer ring, 41a annular portion, 41aa first surface, 41ab second surface, 41ac, 41ad hole, 41b, 41c cylindrical portion, 42 pin, 43 bobbin, 44 coil, 50 Circuit board, 50a, 50b terminals, 51 power supply circuit, 52 sensor, 52a acceleration sensor, 52b temperature sensor, 53 wireless communication circuit, 100 bearing device, 110 shaft, 110a end, 111 nut, 112 spacer, 120 housing, 120a end, 121 lid, A central shaft.

Claims

1. a rolling bearing having an inner ring, an outer ring, and rolling elements; a generator that generates electricity in accordance with the relative rotation of the inner ring with respect to the outer ring, the inner ring has an inner ring outer diameter surface, the outer ring has an outer ring inner diameter surface, the outer ring is disposed radially outward of the inner ring such that the outer ring inner diameter surface faces the inner ring outer diameter surface, the rolling elements are disposed between the outer diameter surface of the inner ring and the inner diameter surface of the outer ring, The generator includes a magnetic ring and a stator. the magnetic ring has a multi-pole magnet in which north and south poles are alternately magnetized in a circumferential direction, and is attached to one of the inner ring and the outer ring; The stator has an outer ring, a plurality of pins, and a coil, the outer ring has an annular portion extending in the circumferential direction and is attached to the other of the inner ring and the outer ring, the annular portion has an opposing surface that faces the magnetic ring with a gap in the axial direction, the plurality of pins are attached to the annular portion so as to be arranged at intervals in the circumferential direction, each of the plurality of pins protrudes from the opposing surface toward the magnetic ring in the axial direction; the outer ring and the plurality of pins are made of a magnetic material, the coil is wound around each of the plurality of pins; The outer ring and the coil are disposed outside the rolling bearing.

2. A sensor, a wireless communication circuit for wirelessly transmitting an output of the sensor; a power supply circuit that rectifies the output of the generator to generate power supplied to the sensor and the wireless communication circuit; a circuit board, the sensor, the wireless communication circuit, and the power supply circuit are mounted on the circuit board; The bearing device according to claim 1 , wherein the circuit board is disposed on the opposing surface so as to avoid the plurality of pins.

3. The annular portion has a plurality of holes formed therein, 3. The bearing device according to claim 1, wherein each of the plurality of pins is attached to the annular portion by being fitted into each of the plurality of holes.

4. A bearing device according to any one of claims 1 to 3, wherein the axial distance between the tip of each of the plurality of pins and the opposing surface is 10 times or more the axial distance between the multi-pole magnet and the tip of each of the plurality of pins.

5. a plurality of electrical components that constitute the sensor, the wireless communication circuit, and the power supply circuit are mounted on the circuit board; 3. The bearing device according to claim 2, wherein a tip of each of the plurality of pins is located farther from the opposing surface in the axial direction than any of the plurality of electrical components.

6. the magnetic ring and the outer ring are attached to the inner ring and the outer ring, respectively; the inner ring has a first end surface that is an end surface of the inner ring in the axial direction, and an inner ring inner diameter surface, an annular first exposed region extending in the circumferential direction and exposed from the outer ring is present at an end of the first end surface on the inner diameter surface side of the inner ring, the outer ring has a second end face that is an end face of the outer ring in the axial direction, and an outer ring outer diameter surface, A bearing device according to any one of claims 1 to 5, wherein an end portion of the second end face on the outer diameter surface side of the outer ring has a second exposed area that is annular and extends in the circumferential direction and is exposed from the outer ring.

7. the magnetic ring and the outer ring are attached to the inner ring and the outer ring, respectively; The bearing device according to any one of claims 1 to 5, wherein a gap that is continuous in the circumferential direction is present between the magnetic ring and the outer ring or the inner ring.

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