Bearing device and generator

Abstract

To provide a small-sized bearing device which is suppressed in an axial protrusion amount, and a generator.SOLUTION: A bearing device 1 comprises: a bearing 2 including an outer ring 6, an inner ring 7 and rolling elements 8; an outer ring 11; a magnetic ring 5; a stator 14 arranged in such a way as to oppose the magnetic ring 5; and a circuit board 12. The circuit board 12 includes an acceleration sensor 22 and a temperature sensor 23 which detect a state of the bearing 2, and a wireless communication circuit 25 for wirelessly transmitting outputs of the acceleration sensor 22 and the temperature sensor 23 to the outside. The magnetic ring 5 and the stator 14 constitute a claw pole type generator G. The magnetic ring 5 is formed into an annular shape. The stator 14 is formed into an arcuate shape. The stator 14 includes a magnetic body member 16 in which claw portions 16a, 16b are formed, and a coil 18. The circuit board 12 is arranged in a position in which the circuit board is not overlapped on the stator 14 on the outer ring 11 when viewed from a rotary shaft direction of the bearing 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a bearing device and a generator. [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. 2006-170624 (Patent Document 1) discloses a bearing device with a wireless sensor that includes a rolling bearing, a rotation sensor that also functions as a generator, and a wireless transmission circuit that wirelessly transmits the output of the rotation sensor.

[0004] In Patent Document 1, the rotation sensor is composed of a magnetic encoder and a magnetic ring with a coil housed inside. The magnetic ring functions as a stator for the rotation sensor of the generator. The rotation sensor is also used as a claw-pole generator. The magnetic ring is fitted onto the inner diameter surface of the outer member and faces the magnetic encoder. A cover that covers the inboard end of the wheel bearing is attached to the outer member. An annular wireless transmitting means is installed in a step portion that extends from the flange portion on the outer diameter surface of the cover to the small diameter portion, and transmits the output of the rotation sensor wirelessly. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-170624 Summary of the Invention [Problem to be solved by the invention]

[0006] The bearing device disclosed in Patent Document 1 has a rotation sensor that also serves as a generator and a wireless transmission means that are arranged axially overlapping one another at one end of the bearing. As a result, the bearing device of Patent Document 1 protrudes significantly in the axial direction. When mounting such a bearing device in equipment, a housing design is required that avoids interference with the significantly protruding rotation sensor and wireless transmission means, which is expected to affect the structural design of the device.

[0007] The present disclosure has been made to solve the above-mentioned problems, and its object is to provide a small-sized bearing device and generator with a reduced amount of axial protrusion. [Means for solving the problem]

[0008] The bearing device disclosed herein includes a bearing including an outer ring, an inner ring, and rolling elements, a fixed member fixed to the outer ring, a magnetic ring fixed to the inner ring, a stator fixed to the fixed member and positioned to face the magnetic ring, and a circuit board. The circuit board includes at least one sensor that detects the state of the bearing and a wireless communication circuit that wirelessly transmits the output of the at least one sensor to an external device. The magnetic ring and the stator form a claw-pole generator. The magnetic ring is annular. The stator is arc-shaped. The stator includes a magnetic member with claws formed thereon and a coil. The circuit board is positioned on the fixed member in a position that does not overlap with the stator when viewed from the direction of the bearing's rotational axis. [Effects of the Invention]

[0009] According to the present disclosure, the circuit board is disposed on the fixed member at a position that does not overlap with the stator when viewed from the direction of the rotation axis of the bearing, thereby reducing the amount of protrusion in the axial direction. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of the entire bearing device of a first embodiment. [Figure 2] FIG. [Figure 3]FIG. 2 is a perspective view of the bearing device with the cover removed, as viewed from the sensor unit side. [Figure 4] FIG. 2 is a front view of the bearing device with the cover removed, viewed from the sensor unit side. [Figure 5] FIG. 5 is a cross-sectional view taken along line AOA in FIG. 4. [Figure 6] FIG. [Figure 7] FIG. 2 is a diagram illustrating the shape of a stator. [Figure 8] FIG. 6 is a cross-sectional view showing a bearing device according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a bearing device according to a third embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a bearing device according to a fourth embodiment. [Figure 11] FIG. 11 is a view taken along the line BB in FIG. [Figure 12] 10A and 10B are diagrams showing modified examples of the arrangement of each member. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] [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 and a sensor unit 3. The bearing device 1 is a bearing with a wireless sensor, in which the sensor unit 3 is fixed to one end of the bearing 2. The sensor unit 3 includes a lid 4. The lid 4 is fixed to the outer end face of the sensor unit 3 and protects the inside of the sensor unit 3.

[0013] FIG. 2 is an exploded perspective view of the bearing device 1. The sensor unit 3 includes an outer ring 11, a circuit board 12, a holder 13, a stator 14, and a lid 4. The outer ring 11 is formed in a cylindrical shape (also referred to as an annular shape) and is fixed to the bearing 2 by press-fitting. A plurality of spacers 15 with threaded holes are fixed to the outer ring 11 by welding, adhesive, or the like. The outer ring 11 functions as a fixing member that is fixed to the outer ring 6, which will be described later. Hereinafter, the outer ring 11 will also be referred to as the fixing member 11. The spacers 15 are used to fix the circuit board 12. Note that the spacers 15 may be omitted. A hole 11c is formed in the outer ring 11 for inserting a temperature sensor 23, which will be described later.

[0014] The magnetic ring 5 is formed in a cylindrical (also called annular) shape and is fixed to the bearing 2 by press-fitting. The magnetic ring 5 includes a core 5a and a multi-pole magnet 5b. The core 5a is formed, for example, by pressing a thin metal plate-shaped blank. The multi-pole magnet 5b is formed, for example, by vulcanizing a magnetic material made by kneading magnetic powder and rubber onto the core 5a, and then magnetizing the N and S poles alternately in the circumferential direction.

[0015] The circuit board 12 includes a sensor board 12a and a processing board 12b. One or more sensors that monitor the state of the bearing 2 are mounted on the sensor board 12a. For example, an acceleration sensor 22 and a temperature sensor 23 (described later) are mounted on the sensor board 12a. The temperature sensor 23 is disposed on the rear surface of the acceleration sensor 22 on the sensor board 12a. A power supply circuit 24, a wireless communication circuit 25, and terminals 26 are mounted on the processing board 12b. The wireless communication circuit 25 includes an antenna unit 27.

[0016] The sensor substrate 12a is adhesively fixed to the outer ring 11. The sensor substrate 12a may be fixed with screws. The processing substrate 12b is fixed to the spacer 15 with screws 19. In the example shown, the circuit substrate 12 is divided into two substrates, the sensor substrate 12a and the processing substrate 12b. However, the circuit substrate 12 may be configured as a single substrate without being divided.

[0017] Power supply circuit 24 rectifies AC power generated by generator G, which will be described later, and converts it into DC power. Wireless communication circuit 25 wirelessly transmits the outputs of sensors (acceleration sensor 22 and temperature sensor 23) that monitor the state of bearing 2 to the outside using antenna unit 27. Terminals 26 are connected to ends 18a, 18b at the start and end of winding of coil 18, which is drawn out from stator 14.

[0018] The holder 13 has an arc shape with a portion cut out in the circumferential direction. The arc shape can also be referred to as a C-shape. A flange 13a extending toward the lid 4 is formed on the outer periphery of the holder 13. The flange 13a may be omitted. An arc-shaped recess 13b corresponding to the shape of the magnetic member 16 is formed on the inner periphery of the holder 13. The holder 13 is fitted so as to abut against the outer ring 11, avoiding the spacer 15.

[0019] The end portion 13c of the holder 13 extends in the circumferential direction so that the central angle of the arc is greater than 180 degrees. With this configuration, the outer ring 11 and the holder 13 are easily fitted together to ensure coaxiality. The holder 13 and the outer ring 11 can be fixed together by press-fitting, bonding, or a combination of press-fitting and bonding. The holder 13 functions as a fixing member together with the outer ring 11. The stator 14 is housed and fixed in the recess 13b of the holder 13. The recess 13b of the holder 13 and the stator 14 may also be fixed together with an adhesive.

[0020] The stator 14 is arc-shaped and includes a magnetic member 16 and a coil 18. Claws 16a and 16b are formed on the inner circumferential surface of the magnetic member 16. The coil 18 is wound around a wall portion 16c on the outer circumferential side of the arc-shaped magnetic member 16. Ends 18a and 18b of the coil 18, which are the start and end of the winding, respectively, are connected to terminals 26 of the process board 12b.

[0021] The lid 4 is fixed to the open side of the outer ring 11, opposite the bearing 2. The lid 4 has a two-layer structure including a heat dissipation portion 4a and an insulating portion 4b. The heat dissipation portion 4a is made of a material with high thermal conductivity (e.g., aluminum, copper, iron, etc.). The insulating portion 4b is made of an insulator (non-conductive material) such as resin with low thermal conductivity.

[0022] Here, the processing board 12b on which the wireless communication circuit 25 is mounted is disposed in a position facing the insulating portion 4b of the lid 4. Therefore, the outer ring 11 and the lid 4 are fixed via the insulating portion 4b of the lid 4. As a result, the wireless communication circuit 25 has a structure that is not sealed with a conductive material such as metal, and wireless communication is possible using the antenna portion 27 of the wireless communication circuit 25. Note that the lid 4 may be integrally molded from an insulating material such as resin, instead of being divided into two parts, the heat dissipation portion 4a and the insulating portion 4b.

[0023] 3 is a perspective view of the bearing device 1 with the lid 4 removed, viewed from the sensor unit 3 side. The bearing device 1 has a sensor unit 3 fixed to one end of a bearing 2. The sensor unit 3 comprises a generator G, with a magnetic ring 5 and a stator 14 arranged opposite each other. The generator G is a claw-pole type generator. The AC power output from the generator G is converted to DC power by a power supply circuit 24.

[0024] FIG. 4 is a front view of the bearing device 1 with the lid 4 removed, viewed from the sensor unit 3 side. The magnetic member 16 of the stator 14 is composed of two members: a magnetic member 16-1 on which claw portions 16a are formed, and a magnetic member 16-2 on which claw portions 16b are formed. The claw portions 16a and 16b are alternately arranged at intervals in the circumferential direction. A coil 18 formed by winding magnet wire multiple times is attached to the magnetic member 16. The stator 14 is disposed opposite a magnetic ring 5 fixed to an inner ring (rotating ring) 7 that rotates around the rotation axis O. When the inner ring 7 rotates, AC power is output from the generator G in the bearing device 1.

[0025] The stator 14 is fixed to the holder 13. An end 13c of the holder 13 extends in the circumferential direction and is inserted into the back surface of the processing substrate 12b. A wireless communication circuit 25 including an antenna unit 27 is mounted on the processing substrate 12b at a position overlapping with the end 13c of the holder 13. Here, the holder 13 is made of a material with low thermal conductivity (e.g., resin). This makes it possible to suppress the effect of temperature rise on the wireless communication circuit 25 mounted on the processing substrate 12b.

[0026] It is also possible to add a heat insulating member between the processing substrate 12b and the outer ring 11. In this way, if the bearing 2 becomes hot, the heat insulating member can suppress the temperature rise of the processing substrate 12b. In this way, other electronic components that are vulnerable to temperature rise may be placed in a position where the temperature rise is suppressed.

[0027] Of the circuit boards 12, the sensor board 12a is adhesively fixed to the outer ring 11, and the processing board 12b is fixed to the spacer 15 of the outer ring 11 shown in FIG. 2 with screws 19. Terminals 20 provided on the sensor board 12a and terminals 21 provided on the processing board 12b are connected by wiring (not shown). Connectors may be used instead of the terminals 20 and 21. In this case, it is preferable to select a connector with a low height so that the axial thickness does not increase. Note that if the sensor board 12a and the processing board 12b are combined into a single board, the terminals 20 and 21 can be omitted.

[0028] Fig. 5 is a diagram showing a cross section taken along line AOA in Fig. 4. Bearing device 1 has a structure in which sensor unit 3 is fixed to bearing 2. Bearing 2 includes outer ring (stationary ring) 6, inner ring (rotating ring) 7, rolling elements 8, a cage 9, and a seal 10. Here, a deep groove ball bearing will be described as an example of bearing 2, but the type of bearing 2 is not limited to a deep groove ball bearing.

[0029] The sensor unit 3 includes an outer ring 11, a holder 13, a circuit board 12, a stator 14, and a lid 4. The magnetic ring 5 includes a core 5a and a multi-pole magnet 5b, and the annular core 5a is fixed to the inner ring 7. The multi-pole magnet 5b, which is bonded to the core 5a, is positioned opposite the stator 14 with a gap between them.

[0030] The outer ring 11 is formed in a cylindrical shape and is fixed by press-fitting into the inner diameter portion of the outer ring 6. The outer diameter of the cylindrical portion 11a of the outer ring 11 is the same as the outer diameter of the outer ring 6. The outer diameter of the cylindrical portion 11a of the outer ring 11 may be formed to be smaller than the outer diameter of the outer ring 6. A holder 13 that holds a stator 14 is fixed to the inner diameter surface of the outer ring 11.

[0031] A sensor board 12a of the circuit board 12 is adhesively fixed to the vertical portion 11b of the outer ring 11, which is perpendicular to the axial direction of the rotation axis O. An acceleration sensor 22 is mounted on the surface of the sensor board 12a facing the lid 4, and a temperature sensor 23 is mounted on the surface facing the bearing 2. A hole 11c is formed in the vertical portion 11b of the outer ring 11. The temperature sensor 23 is inserted into the hole 11c in the vertical portion 11b of the outer ring 11. This allows the temperature sensor 23 to be arranged close to the outer ring 6, allowing the temperature of the bearing 2 to be measured accurately. The temperature sensor 23 may also be arranged so as to come into contact with the outer ring 6.

[0032] The holder 13 is positioned so as to abut against the vertical portion 11b of the outer ring 11, avoiding the spacer 15 shown in Fig. 2, and so as to abut against the cylindrical portion 11a of the outer ring 11 and the flange portion 13a of the holder 13. In this way, the holder 13 is fitted onto the inner diameter surface of the outer ring 11. The holder 13 and the outer ring 11 are fixed together by press-fitting or bonding, or by press-fitting and bonding.

[0033] The holder 13 is made of a material with low thermal conductivity (e.g., resin), and can thermally insulate the bearing 2 from the stator 14. This allows the holder 13 to prevent the temperature rise of the stator 14 from affecting the bearing 2 when the generator G is generating power. The stator 14 includes a magnetic member 16 that combines two magnetic members, 16-1 and 16-2, a bobbin 17, and a coil 18. The structure of the stator 14 will be described in detail later.

[0034] The lid 4 is fixed to the open side of the outer ring 11. The lid 4 has a two-layer structure with a heat dissipation section 4a made of a metal with high thermal conductivity such as aluminum, copper, or iron, and an insulating section 4b with low thermal conductivity that is arranged on the outer periphery of the heat dissipation section 4a. The lid 4 has a folded section 4c that wraps around the inner diameter side of the core metal 5a of the magnetic ring 5. The folded section 4c is designed to increase the volume and surface area of ​​the heat dissipation section 4a, which cools the stator 14. Because the folded section 4c narrows the gaps between the parts of the lid 4, it forms a labyrinth seal (non-contact seal) structure, preventing foreign matter from entering the bearing 2.

[0035] The stator 14 is thermally insulated from metal components such as the outer ring 11 by the holder 13 and the insulating portion 4b of the lid 4. This prevents heat generated by iron loss in the stator 14 when the magnetic ring 5 fixed to the inner ring 7 rotates to generate power from being conducted to the bearing 2. This allows the bearing device 1 to accurately detect heat generated by the rotation of the bearing 2 using the temperature sensor 23.

[0036] 6 is an exploded perspective view of the stator 14. The stator 14 is arc-shaped and includes a magnetic member 16, which is a combination of magnetic members 16-1 and 16-2, a bobbin 17, and a coil 18. Claw portions 16a formed on the inner circumferential surface of the magnetic member 16-1 and claw portions 16b formed on the inner circumferential surface of the magnetic member 16-2 are alternately arranged with gaps in the circumferential direction. The cross-sectional shapes of the magnetic members 16-1 and 16-2 at the positions of the claw portions 16a and 16b are U-shaped.

[0037] The bobbin 17 is arc-shaped and has a groove 17a formed on one end surface. The bobbin 17 is placed in the internal space formed by combining two magnetic members 16-1 and 16-2. The coil 18 is formed by winding magnet wire multiple times around a wall 16c formed on the outer circumferential surface of the magnetic member 16 (16-1 and 16-2). One side of one turn of the coil 18 is housed in the groove 17a of the bobbin 17. The other side of one turn of the coil 18 is housed in the space between the flange 13a of the holder 13 shown in FIG. 5 and the wall 16c formed on the outer circumferential surface of the magnetic member 16.

[0038] The method of assembling the stator 14 will be described. First, the coil 18, which is made by winding magnet wire multiple times in an annular shape, is deformed so that the portion located on the outer periphery side of the wall portion 16c and the portion located on the inner periphery side are each bow-shaped. Next, the inner periphery of the coil 18 is housed in the groove portion 17a of the bobbin 17. Next, the outer periphery of the coil 18 is placed on the outer periphery side of the wall portion 16c of the magnetic member 16, and the magnetic members 16-1 and 16-2 are placed over it. Note that the assembly method is not limited to the method described above.

[0039] As a result, the coil 18 is wound multiple times so as to pass through the cylindrical space formed by the magnetic member 16 along the inner circumferential surface of the wall portion 16c and pass outside the cylindrical space along the outer circumferential surface of the wall portion 16c. The two magnetic members 16-1 and 16-2 may be fixed to each other by adhesive or welding. The bobbin 17 may be omitted from the stator 14.

[0040] As shown in Fig. 4, the magnetic member 16-1 is fixed in contact with the lid 4. The magnetic member 16-2 is fixed in contact with the holder 13. The magnetic member 16, the lid 4, and the holder 13 may be fixed using an adhesive, for example. The recess 13b of the holder 13 shown in Fig. 2 may be provided in the lid 4. The holder 13 and the lid 4 may be provided with a groove that fits with the magnetic member 16.

[0041] 7 is a diagram illustrating the shape of the stator 14. The stator 14 has a cutout portion 14A (indicated by a two-dot chain line) formed by cutting out a portion of the entire circumference, and is formed in an arc shape. The magnetic members 16-1 and 16-2 and the bobbin 17 shown in FIG. 6 are formed with a portion cut to fit the shape of the cutout portion 14A.

[0042] In FIG. 7, the stator 14 has a shape in which the central angle θ of the arc is less than 180 degrees, and a space is formed by the cutout portion 14A on part of the entire circumference. The central angle θ of the arc may be greater than 180 degrees and may be set according to the size of a separate component such as a circuit board. As also shown in FIG. 4, the circuit board 12 is disposed on the outer ring 11 at a position that does not overlap with the stator 14 when viewed from the direction of the rotation axis O of the bearing 2. This allows the bearing device 1 to dispose a separate component such as the circuit board 12 in the space formed in the circumferential direction of the stator 14, thereby reducing the axial width of the sensor unit 3.

[0043] Because stator 14 is arc-shaped, the amount of power generated is lower than with the circular stator used in a typical claw-pole generator. For this reason, the number of poles of claws 16a, 16b and multi-pole magnet 5b, the number of turns of coil 18, the magnetic flux density of multi-pole magnet 5b, and other factors can be optimally set to ensure the power required to drive circuit board 12.

[0044] [Embodiment 2] In the second embodiment, differences from the structure of the bearing device 1 of the first embodiment shown in Fig. 5 will be described. Fig. 8 is a cross-sectional view showing a bearing device 1A of the second embodiment. The bearing device 1A has a structure in which the flange portion 13a of the holder 13 is omitted. Therefore, in the bearing device 1A, the outer periphery of the coil 18 is housed in the space sandwiched between the outer periphery of the wall portion 16c of the magnetic member 16 and the inner periphery of the outer ring 11. This makes it possible to increase the number of turns of the coil 18.

[0045] [Embodiment 3] In the third embodiment, differences from the structure of the bearing device 1 of the first embodiment shown in Fig. 5 will be described. Fig. 9 is a cross-sectional view showing a bearing device 1B of the third embodiment. In the bearing device 1B, the outer ring 6 is the rotating ring and the inner ring 7 is the stationary ring. In the bearing device 1B, a magnetic ring 5 is fixed to the outer ring 6, and a stator 14 is fixed to a fixing member 11 fixed to the inner ring 7. In the bearing device 1B, the magnetic ring 5 of the outer ring 6 and the stator 14 of the inner ring 7 form a claw-pole type generator. Note that the other basic configurations are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0046] (Variation) In the above-described first to third embodiments, the holder 13 is fixed to the outer ring 11, and the stator 14 is positioned by fitting into the recess 13b provided in the holder 13. However, in order to reduce the number of parts, the outer ring (fixing member) 11 and the holder 13 may be formed integrally. In this case, a recess corresponding to the recess 13b may be provided in the outer ring (fixing member) 11.

[0047] [Embodiment 4] In the fourth embodiment, a bearing device 30 used in a main shaft spindle of a machine tool or the like will be described. Fig. 10 is a cross-sectional view showing the bearing device 30 of the fourth embodiment. Fig. 10 shows the bearing device 30 together with a main shaft 34, a housing 35, etc. as the main parts of the spindle device.

[0048] The bearing device 30 includes bearings 31, 32 and a spacer 33 disposed adjacent to the bearings 31, 32. A main shaft 34 is supported by a plurality of bearings 31, 32 provided in a housing 35 so as to be rotatable about a rotation axis O. The bearing 31 includes an outer ring 31g, an inner ring 31i, rolling elements 31t, and a cage 31r. The bearing 32 includes an outer ring 32g, an inner ring 32i, rolling elements 32t, and a cage 32r. The spacer 33 includes an inner ring spacer 33i and an outer ring spacer 33g.

[0049] An inner ring 31i of bearing 31 and an inner ring 32i of bearing 32, which are spaced apart in the axial direction, are fitted in an interference fit (press-fit state) on the main shaft 34. An inner ring spacer 33i is disposed between the inner rings 31i and 32i, and an outer ring spacer 33g is disposed between the outer rings 31g and 32g.

[0050] The bearings 31 and 32 are bearings to which a preload can be applied by an axial force, and may be angular contact ball bearings, deep groove ball bearings, tapered roller bearings, etc. The bearing device 30 shown in Fig. 10 uses angular contact ball bearings, and the two bearings 31 and 32 are arranged in a back-to-back configuration (DB configuration).

[0051] During assembly, bearing 31, spacer 33, bearing 32, and spacer 36 are first inserted onto main shaft 34 in that order, and an initial preload is applied by tightening nut 37. Then, main shaft 34, to which bearings 31 and 32 are attached, is inserted into housing 35 until the right side of outer ring 32g of bearing 32 contacts stepped portion 35a provided on housing 35. Finally, front cover 38 presses outer ring 31g of left-side bearing 31, thereby fixing main shaft 34 to housing 35. A preload (fixed-position preload) is applied to bearings 31 and 32.

[0052] Lubricating oil supply passages 39, 40 for air-oil lubrication are provided at the top of outer ring spacer 33g, and air discharge ports 41, 42 are provided at the bottom. Nozzles (discharge holes) 43, 44 are provided on each side of outer ring spacer 33g, and are connected to each lubricating oil supply passage 39, 40. Air oil is sprayed from nozzles 43, 44 to cool and lubricate bearings 31, 32.

[0053] An arc-shaped stator 46 is mounted in a recess 45 provided on one side (the right side in FIG. 10) of the outer ring spacer 33g so as to avoid the nozzle 44. A lid 47 is fixed next to the stator 46. The lid 47 is arc-shaped so as to avoid the nozzle 44, and is fitted and fixed to the inner diameter surface of the outer ring spacer 33g.

[0054] A magnetic ring 48 is fixed to the inner ring spacer 33i so as to face the stator 46. The stator 46 and the magnetic ring 48 constitute a generator GA. The magnetic ring 48 includes a core metal 48a and a multi-pole magnet 48b.

[0055] A circuit board 49 is fixed to an arc-shaped recess 50 provided on the other side surface (left side in FIG. 10) of the outer ring spacer 33g. The rolling elements 31t of the bearing 31 facing the circuit board 49 are preferably ceramic balls (non-conductive members) so that radio waves for wireless communication can be easily released to the outside.

[0056] Fig. 11 is a view taken along the line BB in Fig. 10. In Fig. 11, the cover 47 is omitted in order to explain the shape of the stator 46. As shown in Fig. 11, an arc-shaped recess 45 is formed on one side surface (the right side in Fig. 10) of the outer ring spacer 33g so as to avoid the nozzle 44. An arc-shaped stator 46 is fixed inside the recess 45. The structure of the stator 46 is the same as that of the stator 14 in Fig. 6, and therefore description thereof will be omitted.

[0057] In bearing device 30, by making stator 46 arc-shaped, it is possible to arrange stator 46 on the same side as nozzle 44. In bearing device 30 of embodiment 4, the fixing member (outer ring 11) described in embodiment 1 is replaced with outer ring spacer 33g, and the inner ring 7 is replaced with inner ring spacer 33i, but the basic configuration is the same.

[0058] Fig. 12 is a diagram showing a modified example of the arrangement of each component. As shown in Fig. 12, both the arc-shaped stator 46 and the circuit board 49 may be arranged at one end (the left side in Fig. 10) of the outer ring spacer 33g, avoiding the nozzle 43.

[0059] (summary) The bearing device 1 of the present disclosure includes a bearing 2 including an outer ring 6, an inner ring 7, and rolling elements 8, an outer ring 11 as a fixed member fixed to the outer ring 6, a magnetic ring 5 fixed to the inner ring 7, a stator 14 fixed to the outer ring 11 and positioned to face the magnetic ring 5, and a circuit board 12. The circuit board 12 includes an acceleration sensor 22 and a temperature sensor 23 that detect the state of the bearing 2, and a wireless communication circuit 25 that wirelessly transmits the outputs of the acceleration sensor 22 and the temperature sensor 23 to an external device. The magnetic ring 5 and the stator 14 form a claw-pole generator G. The magnetic ring 5 is annular. The stator 14 is arc-shaped. The stator 14 includes a magnetic member 16 with claws 16a and 16b formed thereon, and a coil 18. The circuit board 12 is positioned on the outer ring 11 so as not to overlap with the stator 14 when viewed from the direction of the rotation axis O of the bearing 2.

[0060] With this configuration, the circuit board 12 is positioned on the outer ring 11 in a position that does not overlap with the stator 14 when viewed from the direction of the rotation axis O of the bearing 2, thereby reducing the amount of axial protrusion.

[0061] Preferably, the magnetic member 16 has claws 16a and 16b formed on its inner circumferential surface and a wall 16c formed on its outer circumferential surface with a space between them. The claws 16a and 16b are disposed to face the magnetic ring 5. The coil 18 is wound around the wall 16c.

[0062] With this configuration, the coil 18 is wound around the wall portion 16c of the magnetic member 16, so that the circuit board 12 can be placed in the space left open in the circumferential direction, and the amount of protrusion in the axial direction can be reduced.

[0063] Preferably, the outer ring 11 includes a holder 13 that supports the stator 14. A recess 13b is formed in the holder 13. The stator 14 is disposed in the recess 13b.

[0064] With this configuration, the stator 14 is disposed in the recess 13b, making it easy to position the stator 14.

[0065] The bearing device 1B of the present disclosure includes a bearing 2 including an outer ring 6, an inner ring 7, and rolling elements 8, a fixed member fixed to the inner ring 7, a magnetic ring 5 fixed to the outer ring 6, a stator 14 fixed to the fixed member and positioned opposite the magnetic ring 5, and a circuit board 12. The circuit board 12 includes an acceleration sensor 22 and a temperature sensor 23 that detect the state of the bearing 2, and a wireless communication circuit 25 that wirelessly transmits the outputs of the acceleration sensor 22 and the temperature sensor 23 to an external device. The magnetic ring 5 and the stator 14 form a claw-pole generator G. The magnetic ring 5 is annular. The stator 14 is arc-shaped. The stator 14 includes a magnetic member 16 with claws 16a and 16b formed thereon, and a coil 18. The circuit board 12 is positioned on the fixed member so as not to overlap with the stator 14 when viewed from the direction of the rotation axis O of the bearing 2.

[0066] With this configuration, the circuit board 12 is positioned on the outer ring 11 in a position that does not overlap with the stator 14 when viewed from the direction of the rotation axis O of the bearing 2, thereby reducing the amount of axial protrusion.

[0067] The bearing device 30 of the present disclosure includes a spacer 33 disposed adjacent to the bearings 31, 32. The spacer 33 includes an outer ring spacer 33g and an inner ring spacer 33i. An arc-shaped stator 46 is disposed at one end of the outer ring spacer 33g. A magnetic ring 48 facing the stator 46 is fixed to the inner ring spacer 33i. The magnetic ring 48 and the stator 46 constitute a generator GA.

[0068] With this configuration, the bearing device 30 has a generator GA formed at the ends of the outer ring spacer 33g and the inner ring spacer 33i, so that the amount of protrusion of the rotating shaft O in the axial direction can be reduced.

[0069] The generator G of the present disclosure comprises an annular magnetic ring 5 magnetized with alternating north and south poles in the circumferential direction, and a stator 14 disposed opposite the magnetic ring 5. The stator 14 is arc-shaped. The stator 14 includes a magnetic member 16 having claw portions 16a and 16b formed thereon, and a coil 18. The magnetic member 16 has the claw portions 16a and 16b formed on one circumferential surface side, and a wall portion 16c formed on the other circumferential surface side, with a space between them. The claw portions 16a and 16b are disposed opposite the magnetic ring 5. The coil 18 is wound around the wall portion 16c.

[0070] The bearing device and generator of the present disclosure described above can also be applied to a sensor-embedded bearing of the type that does not protrude axially from the bearing.

[0071] By having such a configuration, the generator G has the coil 18 wound around the wall portion 16c of the magnetic material member 16, so that the circuit board 12 can be placed in the space left open in the circumferential direction, thereby reducing the amount of protrusion in the axial direction.

[0072] 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]

[0073] 1, 1A bearing device, 2 bearing, 3 sensor unit, 4 cover, 4a heat dissipation portion, 4b insulating portion, 4c folded portion, 5 magnetic ring, 5a core, 5b multi-pole magnet, 6 outer ring, 7 inner ring, 8 rolling element, 9 retainer, 10 seal, 11 outer ring (fixed member), 11a cylindrical portion, 11b vertical portion, 11c hole, 12 circuit board, 12a sensor board, 12b processing board, 13 holder, 13a flange portion, 13b recess, 13c end portion, 14 stator, 14A notch portion, 15 spacer, 16, 16-1, 16-2 magnetic material member, 16a, 16b claw portion, 16c wall portion, 17 bobbin, 17a groove portion, 18 coil, 19 Screws, 20, 21, 26 terminals, 22 acceleration sensor, 23 temperature sensor, 24 power supply circuit, 25 wireless communication circuit, 27 antenna part, G generator, O rotating shaft.

Claims

1. a bearing including an outer ring, an inner ring, and rolling elements; a fixing member fixed to either the outer ring or the inner ring; a magnetic ring fixed to the other of the outer ring and the inner ring; a stator fixed to the fixed member and disposed so as to face the magnetic ring; a circuit board; 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 magnetic ring and the stator constitute a generator; the magnetic ring is annular, The stator is arc-shaped, the stator includes a magnetic member having claws formed thereon and a coil; the circuit board is disposed on the fixed member at a position not overlapping with the stator when viewed from the rotational axis direction of the bearing, The magnetic member has the claw portion formed on an inner peripheral surface side, and a wall portion formed on an outer peripheral surface side with a space between the inner peripheral surface and the wall portion, the claw portion is disposed to face the magnetic ring, The coil is wound around the wall portion.

2. the fixing member includes a holder that supports the stator, The holder has a recess formed therein, The bearing assembly according to claim 1 , wherein the stator is disposed within the recess.

3. A generator comprising an annular magnetic ring magnetized with N poles and S poles alternately in the circumferential direction, and a stator disposed opposite the magnetic ring, The stator is arc-shaped, the stator includes a magnetic member having claws formed thereon and a coil; The magnetic member has the claw portion formed on one peripheral surface side, and a wall portion formed on the other peripheral surface side across a space from the one peripheral surface side, the claw portion is disposed to face the magnetic ring, The coil is wound around the wall portion.

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