Bearing device

Abstract

To provide a bearing device capable of normally functioning while suppressing the dimension of the bearing device.SOLUTION: A bearing device 1 includes a bearing 2 including an outer ring 3, an inner ring 4 and a rolling element 8, a magnetic ring 7 fixed to the inner ring 4, a stator 5 arranged so as to face the magnetic ring 7 and a radial direction of the bearing 2 and fixed to the outer ring 3, and a circuit board 13. The magnetic ring 7 and the stator 5 constitute a generator G that generates AC power. The circuit board 13 includes at least one sensor that detects a state of the bearing 2, a wireless communication circuit 18, and a power supply circuit 17 that converts AC power generated by the generator G into DC power. The magnetic ring 7, the stator 5, and the circuit board 13 are disposed in an annular space formed by the end portion of the outer ring 3 and the end portion of the inner ring 4 so as not to overlap each other in the axial direction of the bearing 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Bearing devices are known that combine bearings with generators and use them as power sources for sensors, wireless communications, and the like.

[0003] Japanese Patent Application Laid-Open Publication No. 2017-72170 (Patent Document 1) discloses a bearing device with a wireless sensor that wirelessly transmits information from the sensor. The bearing device disclosed in Patent Document 1 has a structure in which a multi-pole ring magnet is fixed to one end of a cage that holds the rolling elements, and a coil is arranged on the seal side facing the multi-pole ring magnet. The bearing device disclosed in Patent Document 1 generates power by the relative rotation between the multi-pole ring magnet and the coil, which are arranged in the axial direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2017-72170 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, the cage has a large amount of play in the axial direction of the bearing as it is used. For this reason, the bearing device of Patent Document 1 is prone to fluctuations in the axial gap between the multi-pole ring magnet and the coil due to play in the cage as it is used. With the bearing device of Patent Document 1, if the gap becomes large, it is expected that the amount of power generated will decrease, affecting the operation of electronic components such as sensors. Conversely, with the bearing device of Patent Document 1, if the gap becomes small, it is expected that the multi-pole ring magnet will come into contact with electronic components such as sensors.

[0006] The present disclosure has been made to solve the above-mentioned problems, and its object is to provide a bearing device that can function normally while keeping the dimensions of the bearing device small. [Means for solving the problem]

[0007] The bearing device disclosed herein includes a bearing including an outer ring, an inner ring, and rolling elements, a magnetic ring fixed to either the outer ring or the inner ring, a stator disposed radially opposite the magnetic ring and fixed to the other of the outer ring or the inner ring, and a circuit board. The magnetic ring and stator form a generator that generates AC power. The circuit board includes at least one sensor that detects the condition of the bearing, a wireless communication circuit that wirelessly transmits the output of the at least one sensor to the outside, and a power supply circuit that converts the AC power generated by the generator into DC power usable by the at least one sensor and the wireless communication circuit. The magnetic ring, stator, and circuit board are arranged within the annular space formed by the ends of the outer ring and the inner ring so as not to overlap each other in the axial direction of the bearing. [Effects of the Invention]

[0008] According to the bearing device of the present disclosure, the magnetic ring, stator, and circuit board are arranged within the annular space so that they do not overlap one another in the axial direction of the bearing. This allows each component to be arranged within the annular space, thereby reducing the dimensions of the bearing. Furthermore, in the bearing device of the present disclosure, for example, the magnetic ring is fixed to the inner ring, and the stator is fixed to the outer ring at an opposing position. The inner ring and outer ring only move slightly in the axial direction of the bearing, and the magnetic ring and stator form a generator, allowing the bearing device to function normally while still being small in size. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of the entire bearing device of a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along a plane including the rotation axis of the bearing. [Figure 3]FIG. 4 is a diagram illustrating a cage. [Figure 4] FIG. 2 is a view of the bearing device as seen from the sensor unit side. [Figure 5] FIG. 2 is an exploded perspective view of the sensor unit. [Figure 6] FIG. 2 is a perspective view of the sensor unit after assembly. [Figure 7] FIG. 10 is a cross-sectional view of a sensor unit and a magnetic ring according to a second embodiment. [Figure 8] FIG. 10 is an exploded perspective view of a sensor unit according to a second embodiment. [Figure 9] FIG. 10 is a perspective view of the sensor unit according to the second embodiment after assembly. [Figure 10] FIG. 11 is a cross-sectional view of a sensor unit and a magnetic ring according to a third embodiment. [Figure 11] FIG. 11 is an exploded perspective view of a sensor unit according to a third embodiment. [Figure 12] FIG. 11 is a perspective view of the sensor unit according to the third embodiment after assembly. [Figure 13] FIG. 10 is a cross-sectional view of a sensor unit and a magnetic ring according to a fourth embodiment. [Figure 14] FIG. 10 is an exploded perspective view of a sensor unit according to a fourth embodiment. [Figure 15] FIG. 10 is a perspective view of the sensor unit of the fourth embodiment after assembly. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, when numbers, quantities, etc. are mentioned, the scope of the present disclosure is not necessarily limited to those numbers, quantities, etc., unless otherwise specified. The same reference numerals are used for the same or equivalent parts, and redundant descriptions may not be repeated. It is intended from the beginning that the configurations in the embodiments may be used in appropriate combinations.

[0011] [Embodiment 1] FIG. 1 is a perspective view of the entire bearing device 1 of the first embodiment. The bearing device 1 includes a bearing 2, a sensor unit 6, and a magnetic ring 7. The bearing 2 includes an outer ring 3 and an inner ring 4. In the bearing 2, for example, the outer ring 3 is a stationary ring and the inner ring 4 is a rotating ring. The bearing 2 will be described as a deep groove ball bearing as an example, but the type of bearing 2 is not limited to a deep groove ball bearing.

[0012] Here, bearing 2 is a standard bearing whose major dimensions (inner diameter, outer diameter, width, etc.) are specified in a specific standard. A standard bearing is a bearing whose dimensions are specified in, for example, ISO or JIS standards. Bearing 2 is a radial bearing, and its major dimensions are those specified in ISO15 or JISB1512-1. Hereinafter, bearing 2 will also be referred to as standard bearing 2.

[0013] The sensor unit 6 includes a stator 5 and a lid 14. The structure of the stator 5 will be described in detail later. The lid 14 is a non-metallic resin member that protects the inside of the sensor unit 6. The magnetic ring 7 is a magnetic member that is magnetized with alternating north and south poles in the circumferential direction. The stator 5 is fixed to the outer ring 3, and the magnetic ring 7 is fixed to the inner ring 4. The stator 5 and the magnetic ring 7 form a generator G. The generator G is a claw-pole type generator, but may be a generator of another structure. The dashed dotted line in Figure 1 indicates the rotation axis O of the bearing 2.

[0014] 2 is a cross-sectional view of bearing 2 taken along a plane including rotation axis O. Bearing 2 includes outer ring 3, inner ring 4, rolling elements 8, cage 9, and seal 10. The bearing 2 may be selected from the model sizes of standard bearings in which the distance W between end face 11 of bearing 2 and rolling elements 8 can accommodate sensor unit 6 and magnetic ring 7. End face 11 is also the end face of outer ring 3.

[0015] A stepped first cutout portion 3a is formed in the inner peripheral surface of one end of the outer ring 3 as a recess at the end of the outer ring 3. A stepped second cutout portion 4a is formed in the outer peripheral surface of one end of the inner ring 4 so as to face the first cutout portion 3a as a recess at the end of the inner ring 4. In the axial direction (also referred to as the axial direction) of the bearing 2, an annular space is formed by an annular recess 50 cut out toward the rolling elements 8 from the outer ring 3 to the inner ring 4 by the first cutout portion 3a and the second cutout portion 4a.

[0016] The sensor unit 6 includes a holding member 12, a circuit board 13, a stator 5, and a lid 14. The holding member 12 is made of a magnetic material and has a partition wall 12a that separates the holding member 12 into a first region 12b and a second region 12c in the radial direction (also referred to as the radial direction) of the bearing 2. The circuit board 13 is fixed to an inner bottom surface 12d of the first region 12b, and the stator 5 is disposed in the second region 12c. The lid 14 protects the circuit board 13 fixed to the inner bottom surface 12d. The circuit board 13 may be sealed using a resin sealing material instead of the lid 14.

[0017] The outer diameter surface of the retaining member 12 on the first region 12b side is fitted into and fixed to a first cutout portion 3a formed in the outer ring 3. The retaining member 12 is press-fitted or bonded so as not to protrude from the end face 11 of the outer ring 3. The retaining member 12 may be fixed by a combination of press-fitting and bonding, or by a method other than these. When the retaining member 12 is fixed to the first cutout portion 3a, a certain gap is secured between the rolling elements 8 and the retaining member 12. This ensures that the rolling elements 8 and the retaining member 12 do not come into contact with each other due to the gap, even when displacement in the axial direction occurs.

[0018] The stator 5 includes two magnetic members 21 and 22, a bobbin 23, and a coil 24. The portion of the holding member 12 including the second region 12c is used as the magnetic member 21 of the stator 5.

[0019] The magnetic ring 7 includes a core 7a and a multi-pole magnet 7b. The multi-pole magnet 7b is formed by vulcanizing and bonding a magnetic material, for example, a mixture of magnetic powder and rubber, to the core 7a, and then magnetizing the N and S poles alternately around the circumferential direction of the bearing 2. The core 7a of the magnetic ring 7 has a flange portion 7c to increase rigidity. The magnetic ring 7 is fixed to the outer diameter surface 4b of the inner ring 4 by press-fitting or the like. The flange portion 7c fits into a second notch portion 4a formed in the inner ring 4. The magnetic ring 7 is positioned so as not to protrude from the end face 20 of the inner ring 4.

[0020] The magnetic ring 7, stator 5, and circuit board 13 are arranged inside the annular recess 50 so that they do not overlap one another in the axial direction of the bearing 2. This allows each component to be arranged inside the annular recess 50, thereby reducing the dimensions of the bearing 2. Furthermore, in the bearing device 1, for example, the magnetic ring 7 is fixed to the inner ring 4, and the stator 5 is fixed to the outer ring 3 at an opposing position. Because the inner ring 4 and outer ring 3 are subject to smaller axial movement of the bearing 2 than the cage 9, a stable amount of power is ensured by the generator G, and the bearing device can function normally while keeping its dimensions small.

[0021] FIG. 3 is a diagram illustrating the retainer 9. The retainer 9 has recesses 93 formed at a predetermined pitch along the circumferential direction of an axial end face 91 of the annular retainer body. A pair of claws 94, 94 are formed to protrude from opening ends that face each other in the circumferential direction of the recess 93. The recess 93 and the pair of claws 94, 94 form a pocket 95 in which the rolling element 8 shown in FIG. 2 is housed. As described above, the retainer 9 has a shape in which one end face 91 is open and the other end face 92 is connected. The retainer 9 is a resin member, and the sensor unit 6 and the magnetic ring 7 are arranged on the open side so as not to protrude from end faces 11 and 20.

[0022] FIG. 4 is a view of the bearing device 1 seen from the sensor unit 6 side. In FIG. 4, part of the lid 14 is omitted so that the interior of the sensor unit 6 can be seen. One or more sensors that monitor the condition of the bearing 2 are mounted on the circuit board 13. For example, an acceleration sensor 15 and a temperature sensor 16 are mounted on the circuit board 13. The temperature sensor 16 is inserted through a hole (not shown) provided in the inner bottom surface 12d of the retaining member 12, and may also be mounted on the back surface of the circuit board 13 so that it is in close proximity to (or in contact with) the end face of the first cutout portion 3a of the outer ring 3. This brings the temperature sensor 16 close to the outer ring 3, allowing it to accurately measure the temperature of the bearing 2.

[0023] The circuit board 13 also has a power supply circuit 17 and a wireless communication circuit 18 mounted thereon. The power supply circuit 17 rectifies the AC power generated by the generator G and converts it into DC power. The acceleration sensor 15, the temperature sensor 16, and the wireless communication circuit 18 use the DC power converted by the power supply circuit 17. Terminals 25 are arranged on the circuit board 13.

[0024] The wireless communication circuit 18 includes an antenna unit 18a. The wireless communication circuit 18 wirelessly transmits the outputs of the acceleration sensor 15 and the temperature sensor 16, which monitor the state of the bearing 2, to the outside using the antenna unit 18a. The circuit board 13 is fixed to the holding member 12 with a plurality of screws 19. The circuit board 13 may also be adhesively fixed to the holding member 12. The circuit board 13 on which the wireless communication circuit 18 is mounted is disposed opposite the resin lid 14. This results in a structure in which the wireless communication circuit 18 is not sealed with a conductive material such as metal. This makes it possible to perform wireless communication using the antenna unit 18a in the wireless communication circuit 18.

[0025] FIG. 5 is an exploded perspective view of the sensor unit 6. FIG. 6 is a perspective view of the sensor unit 6 after assembly. The sensor unit 6 includes a holding member 12, a circuit board 13, and a stator 5. The circuit board 13 is fixed to the inner bottom surface 12d of the first region 12b of the holding member 12. The stator 5 is disposed in the second region 12c of the holding member 12. The stator 5 includes two magnetic members 21 and 22, a bobbin 23, and a coil 24. A part of the holding member 12 including the partition wall 12a of the second region 12c is used as the magnetic member 21 of the stator 5.

[0026] The magnetic members 21 and 22 have a U-shaped cross section. A plurality of claws 21a are formed on the inner periphery of the magnetic member 21. A plurality of claws 22a are formed on the inner periphery of the magnetic member 22. A coil 24 formed by winding a magnet wire multiple times is placed in a groove provided in the circumferential direction of the bobbin 23. The bobbin 23 may be omitted.

[0027] The method of assembling the stator 5 will be described below. First, the bobbin 23 wound with the coil 24 is inserted into the magnetic member 22, and the magnetic member 21 and the magnetic member 22 are assembled so that the claws 21a of the magnetic member 21 and the claws 22a of the magnetic member 22 are alternately arranged with gaps in the circumferential direction. Next, the outer peripheral surface 22b of the magnetic member 22 is fixed so as to fit into the inner peripheral surface of the partition wall 12a of the magnetic member 21.

[0028] The multiple claws 21a of the magnetic member 21 and the multiple claws 22a of the magnetic member 22 are arranged facing each other with a gap maintained between them and the multi-pole magnet 7b of the magnetic ring 7 shown in Fig. 2. The multiple claws 21a of the magnetic member 21 and the multiple claws 22a of the magnetic member 22 in the stator 5, together with the magnetic ring 7, form a claw-pole type generator G. The total number of the multiple claws 21a, 22a is equal to the number of poles (the total number of north and south poles) of the multi-pole magnet 7b.

[0029] The magnetic flux emitted from the north pole of the multi-pole magnet 7b enters the magnetic member 21 (or magnetic member 22) through, for example, the multiple claws 21a (or multiple claws 22a) that are magnetic poles, circulates around the coil 24, passes through the multiple adjacent claws 22a (or multiple claws 21a), and returns to the south pole of the multi-pole magnet 7b. When the positions of the north and south poles of the multi-pole magnet 7b are swapped due to the rotation of the inner ring 4, the direction of the magnetic flux is reversed. The alternating magnetic field generated in this way generates alternating current at both ends of the coil 24.

[0030] The start and end (not shown) of the coil 24 drawn out from the stator 5 are connected to terminals 25 provided on the circuit board 13. The AC power output from the generator G as the inner ring 4 rotates is converted into DC power by the power supply circuit 17.

[0031] The sensor unit 6 of the bearing device 1 is divided into two regions, a first region 12b and a second region 12c, by a partition wall 12a in the radial direction of the retaining member 12. A circuit board 13 is disposed in the first region 12b, and a stator 5 of a claw-pole type generator G is disposed in the second region 12c. The magnetic ring 7 is disposed on the inner diameter side facing the stator 5.

[0032] In this way, the bearing device 1 has a structure in which the circuit board 13, stator 5, and magnetic ring 7 are arranged in this order so as not to overlap one another in the axial direction of the bearing 2. Furthermore, the bearing device 1 is shaped so that the sensor unit 6 does not protrude beyond the end face 11 of the bearing 2, and the magnetic ring 7 does not protrude beyond the end face 20 of the inner ring 4. This allows the sensor unit 6 of the bearing device 1 to be made thin in the axial direction.

[0033] The bearing device 1 has a stator 5 and a magnetic ring 7 arranged in the radial direction to form a claw-pole type generator G. Because the stator 5 and the magnetic ring 7 are fixed to components that are less likely to wobble when the bearing device 1 is used, a stable amount of power can be generated by the generator G.

[0034] Here, the holding member 12 is divided by a partition wall 12a into two regions, a first region 12b and a second region 12c. The portion of the holding member 12 including the first region 12b is used to hold the circuit board 13, and the portion of the holding member 12 including the second region 12c is also used as the magnetic member 21. Therefore, the bearing device 1 can reduce the number of parts and can firmly fix the stator 5 to the holding member 12.

[0035] [Embodiment 2] In the second embodiment, a sensor unit 6A having a different structure from the sensor unit 6 of the first embodiment will be described. FIG. 7 is a cross-sectional view of the sensor unit 6A and the magnetic ring 7 in the second embodiment. FIG. 8 is an exploded perspective view of the sensor unit 6A of the second embodiment. FIG. 9 is a perspective view of the sensor unit 6A of the second embodiment after assembly. In the following, a description of the same configuration as the sensor unit 6 of the first embodiment will be omitted.

[0036] The sensor unit 6A includes a holding member 12A, a circuit board 13, a stator 5A, and a lid 14. The partition wall 12a of the first embodiment is omitted from the holding member 12A. The holding member 12A is annular and has a U-shaped cross section, including an outer circumferential portion 12Ab, an inner circumferential portion 12Aa, and a bottom portion 12Ad connecting the outer circumferential portion 12Ab and the inner circumferential portion 12Aa. The stator 5A is fixed to the side surface of the inner circumferential portion 12Aa by press-fitting. The stator 5A may be fixed by adhesive, or may be fixed by a combination of press-fitting and adhesive. The circuit board 13 is fixed to the bottom portion 12Ad of the holding member 12A.

[0037] The stator 5A includes a magnetic member 26, a bobbin 23, and a coil 24. The magnetic member 26 includes a magnetic member 26-1 and a magnetic member 26-2. The magnetic members 26-1 and 26-2 have a U-shaped cross section. A plurality of claw portions 26a are formed on the inner periphery of the magnetic member 26-1. A plurality of claw portions 26b are formed on the inner periphery of the magnetic member 26-2. The plurality of claw portions 26a and the plurality of claw portions 26b are alternately arranged with gaps between them in the circumferential direction.

[0038] A plurality of recesses 26c and protrusions 26d are formed on the outer periphery of the magnetic member 26-1 and the magnetic member 26-2. By fitting the recesses 26c into the protrusions 26d, it becomes easy to align the plurality of claws 26a with the plurality of claws 26b.

[0039] The holding member 12A, the magnetic member 26-1, and the magnetic member 26-2 have a simple U-shaped cross section, which makes press working easy and reduces manufacturing costs.

[0040] [Embodiment 3] In the third embodiment, a sensor unit 6B having a different structure from the sensor unit 6 of the first embodiment will be described. Fig. 10 is a cross-sectional view of the sensor unit 6B and the magnetic ring 7 of the third embodiment. Fig. 11 is an exploded perspective view of the sensor unit 6B of the third embodiment. Fig. 12 is a perspective view of the sensor unit 6B of the third embodiment after assembly. In the following, a description of the same configuration as the sensor unit 6 of the first embodiment will be omitted.

[0041] The sensor unit 6B includes a holding member 12B, a circuit board 13, a stator 5B, and a lid 14. The holding member 12B of the sensor unit 6B functions to fix the circuit board 13 and also functions as the magnetic member 27 of the stator 5B. The holding member 12B (magnetic member 27) is annular in shape and has a U-shaped cross section having an outer circumferential portion 27a, an inner circumferential portion 27b, and a bottom portion 27c connecting the outer circumferential portion 27a and the inner circumferential portion 27b. The inner circumferential portion 27b is formed by a plurality of claw portions 27d. The bottom portion 27c has a plurality of recesses 27e formed in the bearing 2 and spaced apart in the circumferential direction.

[0042] The stator 5B includes a magnetic member 28. The magnetic member 28 is annular in shape and has a U-shaped cross section, with an outer circumferential portion 28a, an inner circumferential portion 28b, and a bottom portion 28c connecting the outer circumferential portion 28a and the inner circumferential portion 28b. The inner circumferential portion 28b is formed by a plurality of claws 28d that face the plurality of claws 27d of the magnetic member 27. A plurality of protrusions 28e are formed at the end of the outer circumferential portion 28a in the axial direction of the bearing 2, and are spaced apart in the circumferential direction of the bearing 2.

[0043] The method of assembling the stator 5B is described below. With the bobbin 23 wound with the coil 24 inserted inside the magnetic member 28, the protrusions 28e of the magnetic member 28 are fitted into the recesses 27e of the magnetic member 27. By fitting the multiple recesses 27e into the multiple protrusions 28e, the multiple claws 27d of the magnetic member 27 and the multiple claws 28d of the magnetic member 28 are alternately arranged with gaps in the circumferential direction. The multiple recesses 27e and the multiple protrusions 28e make it easy to align the multiple claws 27d with the multiple claws 28d. The end face of the magnetic member 28, excluding the protrusions 28e, abuts against the bottom 27c of the magnetic member 27.

[0044] The recessed portion 27e of the magnetic member 27 and the protruding portion 28e of the magnetic member 28 are fixed by press-fitting. However, the recessed portion 27e and the protruding portion 28e may also be fixed by adhesive or laser welding. Alternatively, the recessed portion 27e and the protruding portion 28e may be fixed by a combination of press-fitting, adhesive, and welding. By fitting the recessed portion 27e and the protruding portion 28e together, the two magnetic members 27, 28 can be aligned coaxially without using a jig, and the multiple claw portions 27d, 28d can be easily aligned. It is preferable to form three or more recessed portions 27e and three or more protruding portions 28e.

[0045] The holding member 12B also serves as the magnetic member 27, thereby reducing the number of components. The magnetic member 27 and the magnetic member 28 have a simple U-shaped cross section, which facilitates press working and reduces manufacturing costs.

[0046] The recessed portion 27e and the protruding portion 28e may be omitted. In this case, after the coaxial relationship between the magnetic members 27 and 28 and the positioning of the plurality of claw portions 27d and 28d are achieved using a jig (not shown), the contact surfaces between the bottom portion 27c of the magnetic member 27 and the end portion of the outer circumferential portion 28a of the magnetic member 28 may be fixed by laser welding or the like.

[0047] [Embodiment 4] In the fourth embodiment, a sensor unit 6C having a different structure from the sensor unit 6 of the first embodiment will be described. Fig. 13 is a cross-sectional view of the sensor unit 6C and the magnetic ring 7 in the fourth embodiment. Fig. 14 is an exploded perspective view of the sensor unit 6C of the fourth embodiment. Fig. 15 is a perspective view of the sensor unit 6C of the fourth embodiment after assembly. In the following, a description of the same configuration as the sensor unit 6 of the first embodiment will be omitted.

[0048] The sensor unit 6C includes a circuit board 13 and a stator 5C. In the sensor unit 6C, the holding member that holds the stator 5C is formed of a magnetic member 29 that extends in the radial direction of the bearing 2. The magnetic member 29 includes a magnetic member 29-1 and a magnetic member 29-2. The magnetic member 29-1 is annular in shape and has a U-shaped cross section that includes an outer circumferential portion 29-1b, an inner circumferential portion 29-1a, and a bottom portion 29-1d that connects the outer circumferential portion 29-1b and the inner circumferential portion 29-1a. The inner circumferential portion 29-1a is formed by a plurality of claw portions 29a.

[0049] The magnetic member 29-2 has a ring shape and a U-shaped cross section, including an outer circumferential portion 29-2b, an inner circumferential portion 29-2a, and a bottom portion 29-2d connecting the outer circumferential portion 29-2b and the inner circumferential portion 29-2a. The inner circumferential portion 29-2a is formed by a plurality of claw portions 29b. The plurality of claw portions 29a and the plurality of claw portions 29b are alternately arranged with gaps in the circumferential direction.

[0050] A plurality of protrusions 29c and recesses 29d are formed on outer circumferential portions 29-1b and 29-2b of the magnetic member 29-1 and the magnetic member 29-2. By fitting the protrusions 29c and the recesses 29d together, it becomes easy to align the plurality of claws 29a and the plurality of claws 29b. The magnetic member 29 is disposed at one end of the bearing 2.

[0051] The bobbin 23 around which the coil 24 is wound is disposed on the inner circumferential side where the plurality of claws 29a and 29b are located. The circuit board 13 is disposed on the outer circumferential side opposite the radial direction of the coil 24 and the bearing 2. The circuit board 13 is fixed to the bottom 29-1d of the magnetic member 29-1 with a screw (not shown), for example. A hole 29e is formed in a position (bottom 29-2d) on the side surface of the magnetic member 29-2 opposite the position where the antenna unit 18a of the wireless communication circuit 18 is disposed.

[0052] The hole 29e is closed by a resin member 30, which is a non-conductive member. This allows the sensor unit 6C to transmit radio waves for wireless communication to the outside through the hole 29e, and also protects the coil 24, circuit board 13, and other components located inside by preventing foreign matter from entering the internal space of the magnetic member 29 from the outside. Note that a resin sealing material may be injected through the hole 29e to cover the circuit board 13 and other components with the resin material. In this case, multiple holes may be provided in the circumferential direction of the bottom 29-2d of the magnetic member 29-2, and the resin sealing material may be injected through each hole so that no air bubbles remain in the internal space of the magnetic member 29.

[0053] In the sensor unit 6C, the circuit board 13 is mounted in an internal space formed by the magnetic material member 29-1 and the magnetic material member 29-2. This allows the circuit board 13 to be protected by the magnetic material member 29. In the sensor unit 6C, the holding member itself is formed by the magnetic material member 29-1, and the magnetic material member 29-2 also serves as a lid, allowing the number of parts to be reduced.

[0054] (Variation) In the above-described embodiment, an example was described in which the outer ring 3 was a fixed ring and the inner ring 4 was a rotating ring, but the outer ring 3 may be a rotating ring and the inner ring 4 a fixed ring. In this case, the magnetic ring 7 may be fixed to the outer ring 3, and the sensor units 6, 6A, 6B, and 6C may be fixed to the inner ring 4.

[0055] (summary) The bearing device 1 of the present disclosure includes a bearing 2 including an outer ring 3, an inner ring 4, and rolling elements 8, a magnetic ring 7 fixed to either the outer ring 3 or the inner ring 4, a stator 5 disposed radially opposite the magnetic ring 7 and fixed to the other of the outer ring 3 or the inner ring 4, and a circuit board 13. The magnetic ring 7 and stator 5 constitute a generator G that generates AC power. The circuit board 13 includes at least one sensor (e.g., an acceleration sensor 15, a temperature sensor 16) that detects the state of the bearing 2, a wireless communication circuit 18 that wirelessly transmits the output of the at least one sensor to the outside, and a power supply circuit 17 that converts the AC power generated by the generator G into DC power usable by the at least one sensor and the wireless communication circuit 18. The magnetic ring 7, stator 5, and circuit board 13 are arranged within the annular space formed by the end of the outer ring 3 and the end of the inner ring 4 so as not to overlap each other in the axial direction of the bearing 2.

[0056] With this configuration, the magnetic ring 7, stator 5, and circuit board 13 are arranged within the annular space so that they do not overlap one another in the axial direction of the bearing 2. This allows each component to be arranged within the annular space, thereby reducing the dimensions of the bearing 2. Furthermore, in the bearing device 1, for example, the magnetic ring 7 is fixed to the inner ring 4, and the stator 5 is fixed to the outer ring 3 at an opposing position. Because the inner ring 4 and outer ring 3 are subject to small fluctuations in the axial direction of the bearing 2, a stable amount of power is ensured by the generator G, and the bearing device can function normally while keeping its dimensions small.

[0057] Preferably, the annular space is formed by a first notch portion 3a formed in the inner peripheral surface of one end of the outer ring 3 and a second notch portion 4a formed in the outer peripheral surface of one end of the inner ring 4 so as to face the first notch portion 3a.

[0058] With this configuration, the dimensions of the bearing 2 can be reduced because each component can be arranged in the annular space formed by the first cutout portion 3a and the second cutout portion 4a.

[0059] Preferably, a holding member 12 that holds the circuit board 13 and the stator 5 is fixed to one of the first notch portion 3a or the second notch portion 4a, and a magnetic ring 7 is fixed to the other of the first notch portion 3a or the second notch portion 4a.

[0060] With this configuration, for example, the holding member 12 that holds the circuit board 13 and the stator 5 is fixed to the first notch 3a, and the magnetic ring 7 is fixed to the second notch 4a. Therefore, the stator 5 and the magnetic ring 7 are fixed to parts that are less likely to wobble when the bearing device 1 is used, so a stable amount of power can be generated by the generator G.

[0061] Preferably, the retaining member 12 is made of a magnetic material having a partition wall 12a that separates the retaining member 12 into a first region 12b and a second region 12c in the radial direction of the bearing 2. A portion of the retaining member 12 including either the first region 12b or the second region 12c is used as the stator 5.

[0062] With this configuration, for example, holding member 12 is divided by partition wall 12a into two regions, first region 12b and second region 12c. The portion of holding member 12 including first region 12b is used to hold circuit board 13, and the portion of holding member 12 including second region 12c is also used as magnetic member 21. Therefore, bearing device 1 can reduce the number of parts and can firmly fix stator 5 to holding member 12.

[0063] Preferably, the holding member 12A has an annular shape and a U-shaped cross section having an outer circumferential portion 12Ab, an inner circumferential portion 12Aa, and a bottom portion 12Ad connecting the outer circumferential portion 12Ab and the inner circumferential portion 12Aa. The stator 5 is fixed to either the outer circumferential portion 12Ab or the inner circumferential portion 12Aa, and the circuit board 13 is fixed to the bottom portion 12Ad.

[0064] With this configuration, the holding member 12A has a simple U-shaped cross section, which makes it easy to press, thereby reducing manufacturing costs.

[0065] Preferably, the stator 5B includes the coil 24, a magnetic material member 27 having a plurality of claws 27d formed thereon, and a magnetic material member 28 having a plurality of claws 28d formed thereon. The coil 24 is housed in an internal space formed by combining the magnetic material member 27 and the magnetic material member 28. The holding member 12B is the magnetic material member 27. The magnetic material member 27 is annular in shape and has a U-shaped cross section, including an outer circumferential portion 27a, an inner circumferential portion 27b, and a bottom portion 27c connecting the outer circumferential portion 27a and the inner circumferential portion 27b. The inner circumferential portion 27b is formed by the plurality of claws 27d. The bottom portion 27c has a plurality of recesses 27e spaced apart in the circumferential direction of the bearing 2. The magnetic material member 28 is annular in shape and has a U-shaped cross section, including the outer circumferential portion 28a, the inner circumferential portion 28b, and the bottom portion 28c connecting the outer circumferential portion 28a and the inner circumferential portion 28b. The inner peripheral portion 28b is formed by a plurality of claws 28d that face the plurality of claws 27d. A plurality of protrusions 28e are formed at the end of the outer peripheral portion 28a in the axial direction of the bearing 2, and are spaced apart in the circumferential direction of the bearing 2. The plurality of recesses 27e and the plurality of protrusions 28e fit together, so that the plurality of claws 27d and the plurality of claws 28d are alternately arranged with gaps in the circumferential direction of the bearing 2.

[0066] With this configuration, the holding member 12B also functions as the magnetic member 27, thereby reducing the number of parts. The magnetic members 27 and 28 have a simple U-shaped cross section, which facilitates press working and reduces manufacturing costs. By fitting the recessed portion 27e into the protruding portion 28e, the two magnetic members 27 and 28 can be coaxially aligned without using a jig, and the multiple claw portions 27d and 28d can be easily aligned.

[0067] Preferably, the stator 5C includes the coil 24, a magnetic member 29-1 having a plurality of claws 29a formed thereon, and a magnetic member 29-2 having a plurality of claws 29b formed thereon. The coil 24 is housed in an internal space formed by combining the magnetic member 29-1 and the magnetic member 29-2. The magnetic member 29-1 and the magnetic member 29-2 serve as holding members. The magnetic member 29-1 has an annular shape and a U-shaped cross section having an outer circumferential portion 29-1b, an inner circumferential portion 29-1a, and a bottom portion 29-1d connecting the outer circumferential portion 29-1b and the inner circumferential portion 29-1a. The outer circumferential portion 29-1b or the inner circumferential portion 29-1a is formed by the plurality of claws 29a. The magnetic material member 29-2 has an annular shape and a U-shaped cross section, having an outer circumferential portion 29-2b, an inner circumferential portion 29-2a, and a bottom portion 29-2d connecting the outer circumferential portion 29-2b and the inner circumferential portion 29-2a. The outer circumferential portion 29-2b or the inner circumferential portion 29-2a is formed by a plurality of claws 29b. The magnetic material member 29 is disposed at one end of the bearing 2. The plurality of claws 29a and the plurality of claws 29b are alternately arranged with gaps in the circumferential direction of the bearing 2. The coil 24 is disposed on the side where the plurality of claws 29a and the plurality of claws 29b are located. The circuit board 13 is disposed on the radially opposite side of the bearing from the coil 24. The wireless communication circuit 18 includes an antenna portion 18a. A hole 29e is formed in a side surface of the magnetic material member 29-2 opposite the position where the antenna portion 18a is located.

[0068] With this configuration, the holding member itself is made of the magnetic member 29-1, and the magnetic member 29-2 also serves as a lid, thereby reducing the number of parts. Furthermore, radio waves for wireless communication can be transmitted to the outside from the hole 29e, and the coil 24, circuit board 13, etc. located inside can be protected by preventing foreign matter from entering the internal space of the magnetic member 29 from the outside.

[0069] The bearing device 1 of the present disclosure includes a standard bearing 2, the main dimensions of which, including the outer ring 3, inner ring 4, and rolling elements 8, are specified in a specific standard. The bearing device 1 also includes a magnetic ring 7 fixed to either the outer ring 3 or the inner ring 4, a stator 5 disposed radially opposite the magnetic ring 7 and the standard bearing 2 and fixed to the other of the outer ring 3 or the inner ring 4, and a circuit board 13. The magnetic ring 7 and stator 5 form a generator G that generates AC power. The circuit board 13 includes at least one sensor (e.g., an acceleration sensor 15, a temperature sensor 16) that detects the state of the standard bearing 2, a wireless communication circuit 18 that wirelessly transmits the output of the at least one sensor to the outside, and a power supply circuit 17 that converts the AC power generated by the generator G into DC power usable by the at least one sensor and the wireless communication circuit 18. The magnetic ring 7, stator 5, and circuit board 13 are disposed within an annular space formed by the end of the outer ring 3 and the end of the inner ring 4.

[0070] With this configuration, each component can be placed within the annular space, thereby reducing the dimensions of the standard bearing 2. Furthermore, in the bearing device 1, for example, the magnetic ring 7 is fixed to the inner ring 4, and the stator 5 is fixed to the outer ring 3 at the opposite position. Because the inner ring 4 and the outer ring 3 are subject to little axial movement of the bearing 2, a stable amount of power can be generated by the generator G, and the bearing device can function normally while keeping its dimensions small.

[0071] Preferably, the magnetic ring 7 , the stator 5 , and the circuit board 13 are arranged in the annular space so as not to overlap one another in the axial direction of the standard bearing 2 .

[0072] By providing such a configuration, each component can be arranged within the annular space, thereby reducing the dimensions of the standard bearing 2.

[0073] Preferably, the circuit board 13 has an arcuate shape. The at least one sensor, the wireless communication circuit 18, and the power supply circuit 17 are arranged on the circumference of the circuit board 13 so as not to overlap one another in the axial direction.

[0074] By adopting such a configuration, multiple electronic components can be arranged on the circumference of the circuit board 13 without increasing the axial thickness of the standard bearing 2, thereby reducing the dimensions of the standard bearing 2.

[0075] Preferably, the specific standard is ISO or JIS. By providing such a configuration, it can be applied to standard bearings with dimensions specified by ISO or JIS standards.

[0076] Preferably, the standard bearing 2 is a radial bearing, the major dimensions of which are specified in ISO15 or JIS B1512-1.

[0077] With this configuration, it can be used with standard bearings with dimensions specified in ISO15 or JIS B1512-1.

[0078] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0079] 1 bearing device, 2 bearing, standard bearing, 3 outer ring, 3a first notch portion, 4 inner ring, 4a second notch portion, 5, 5A, 5B, 5C stator, 6, 6A, 6B, 6C sensor unit, 7 magnetic ring, 7a core metal, 7b multi-pole magnet, 8 rolling element, 9 retainer, 10 seal, 12, 12A, 12B retaining member, 12Aa, 27b, 28b, 29-1a inner peripheral portion, 12Ab, 27a, 28a, 29-1b outer peripheral portion, 12Ad, 27c, 28c, 29-1d bottom portion, 12a partition wall, 12b first region, 12c second region, 13 circuit board, 14 lid, 15 acceleration sensor, 16 temperature sensor, 17 power supply circuit, 18 wireless communication circuit, 18a Antenna portion, 21, 22, 26, 27, 28, 29 magnetic members, 21a, 22a, 26a, 26b, 27d, 28d, 29a, 29b multiple claw portions, 23 bobbin, 24 coil, 26c, 27e, 29d recesses, 26d, 28e, 29c protrusions, 29e hole portion, 30 resin member, 50 annular recess, G generator, O rotating shaft.

Claims

1. a bearing including an outer ring, an inner ring, and rolling elements; a magnetic ring fixed to either the outer ring or the inner ring; a stator disposed so as to face the magnetic ring in the radial direction of the bearing and fixed to the other of the outer ring and the inner ring; a circuit board; the magnetic ring and the stator constitute a generator that generates AC power; the circuit board includes at least one sensor that detects a state of the bearing, and a wireless communication circuit that wirelessly transmits an output of the at least one sensor to an external device; The bearing device further includes a non-conductive resin member arranged at a position facing the wireless communication circuit in the axial direction of the bearing.

2. 2. The bearing device according to claim 1, wherein the magnetic ring, the stator, and the circuit board are arranged in an annular space formed by the end of the outer ring and the end of the inner ring so as not to overlap each other in the axial direction of the bearing.

3. 3. The bearing device according to claim 2, wherein the annular space is defined by a first cutout portion formed in the inner circumferential surface of one end of the outer ring and a second cutout portion formed in the outer circumferential surface of one end of the inner ring so as to face the first cutout portion.

4. 4. The bearing device according to claim 3, wherein a holding member that holds the circuit board and the stator is fixed to one of the first notch portion or the second notch portion, and the magnetic ring is fixed to the other of the first notch portion or the second notch portion.

5. the retaining member is made of a magnetic material and has a partition wall that separates the retaining member into a first region and a second region in a radial direction of the bearing, The bearing device according to claim 4 , wherein a portion of the retaining member including either the first region or the second region is used as the stator.

6. the holding member has an annular shape and a U-shaped cross section having an outer circumferential portion, an inner circumferential portion, and a bottom portion connecting the outer circumferential portion and the inner circumferential portion; the stator is fixed to either the outer circumferential portion or the inner circumferential portion, The bearing device according to claim 4 , wherein the circuit board is fixed to the bottom portion.

7. the stator includes a coil, a first magnetic member having a first plurality of claws formed thereon, and a second magnetic member having a second plurality of claws formed thereon; the coil is housed in an internal space formed by combining the first magnetic member and the second magnetic member; the holding member is the first magnetic member, the first magnetic member has an annular shape and a U-shaped cross section having a first outer circumferential portion, a first inner circumferential portion, and a first bottom portion connecting the first outer circumferential portion and the first inner circumferential portion; one of the first inner peripheral portion and the first outer peripheral portion is formed by the first plurality of claw portions; The first bottom portion has a plurality of recesses formed therein that are spaced apart in a circumferential direction of the bearing, the second magnetic member has an annular shape and a U-shaped cross section having a second outer circumferential portion, a second inner circumferential portion, and a second bottom portion connecting the second outer circumferential portion and the second inner circumferential portion; one of the second inner peripheral portion and the second outer peripheral portion is formed by the second plurality of claw portions that face the first plurality of claw portions, a plurality of protrusions spaced apart in a circumferential direction of the bearing are formed at an end of the bearing in an axial direction of the other of the second outer peripheral portion or the second inner peripheral portion; 5. The bearing device according to claim 4, wherein the first plurality of claw portions and the second plurality of claw portions are alternately arranged with gaps in the circumferential direction of the bearing by fitting the plurality of recesses and the plurality of protrusions together.

8. the stator includes a coil, a first magnetic member having a first plurality of claws formed thereon, and a second magnetic member having a second plurality of claws formed thereon; the coil is housed in an internal space formed by combining the first magnetic member and the second magnetic member; the holding member is the first magnetic member and the second magnetic member, the first magnetic member has an annular shape and a U-shaped cross section having a first outer circumferential portion, a first inner circumferential portion, and a first bottom portion connecting the first outer circumferential portion and the first inner circumferential portion; the first outer circumferential portion or the first inner circumferential portion is formed by the first plurality of claw portions, the second magnetic member has an annular shape and a U-shaped cross section having a second outer circumferential portion, a second inner circumferential portion, and a second bottom portion connecting the second outer circumferential portion and the second inner circumferential portion; the second outer circumferential portion or the second inner circumferential portion is formed by the second plurality of claw portions, the second magnetic member is disposed at one end of the bearing, the first plurality of claw portions and the second plurality of claw portions are alternately arranged with gaps in the circumferential direction of the bearing, the coil is disposed on a side where the first plurality of claws and the second plurality of claws are located, the circuit board is disposed on a radially opposite side of the coil and the bearing; the wireless communication circuit includes an antenna unit; 5. The bearing device according to claim 4, wherein a hole is formed in a side surface of the second magnetic member opposite to a position where the antenna portion is disposed.

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