Bearing device, spacer and manufacturing method

Abstract

To provide a bearing device including a power generator capable of simplifying a structure of the power generator and reducing initial production costs.SOLUTION: A bearing device 1 comprises a magnetic ring 8 fixed to an inner ring 3, and a stator 9 fixed to an outer ring 2 so as to be opposed to the magnetic ring 8. The magnetic ring 8 and the stator 9 constitute a claw pole type power generator G. The stator 9 includes a coil 12, and a magnetic yoke surrounding the coil 12. The magnetic yoke is constituted by combining a first member 10-1 and a second member 10-2 that are magnetic bodies. The first member 10-1 and the second member 10-2 have the same shape. The first member 10-1 and the second member 10-2 each comprise a plurality of second claws 10b arranged in a comb tooth shape. A plurality of first claws 10b of the first member 10-1 and the plurality of second claws 10b of the second member 10-2 are alternately arranged in a surface opposed to the magnetic ring 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bearing device, a spacer, and a manufacturing method. [Background technology]

[0002] It is known to combine a bearing with a generator and use it as a power source for sensors, wireless communication, etc. Japanese Patent Application Laid-Open No. 2006-170624 (Patent Document 1) discloses a bearing 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-170624 Summary of the Invention [Problem to be solved by the invention]

[0004] The rotation sensor of a bearing with a wireless sensor that also serves as a generator, as disclosed in JP 2006-170624, is composed of a magnetic encoder and a magnetic ring with a coil housed inside. The magnetic ring also functions as a stator for the generator's rotation sensor. The rotation sensor is configured as a claw-pole generator.

[0005] The magnetic ring is a ring body with a substantially rectangular cross section in a plane including the bearing's rotation axis. The magnetic ring is formed by combining two magnetic ring members each having a groove-shaped cross section that opens toward the rotation axis direction. The two magnetic ring members are arranged facing each other with their openings facing each other, and the two members are arranged so that they abut each other at their outer diameters without any gaps. In this way, by eliminating any gaps at the abutting points between the two magnetic ring members, the magnetic resistance at the mating part in the magnetic circuit inside the magnetic ring is kept small.

[0006] The magnetic ring described in Patent Document 1 requires the preparation of two magnetic ring members with different shapes. When the magnetic ring members are press-molded using a die, separate dies are required for each, which increases the initial manufacturing cost.

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a bearing device, a spacer, and a manufacturing method thereof that can simplify the configuration of a generator and reduce the initial manufacturing cost. [Means for solving the problem]

[0008] The present disclosure relates to a bearing device or spacer that rotatably supports a rotating member. The bearing device or spacer includes a magnetic ring fixed to the rotating member and a stator fixed to a non-rotating member so as to face the magnetic ring. The magnetic ring and stator form a claw-pole generator. The stator includes a coil and a magnetic yoke surrounding the coil. The magnetic yoke is formed by combining a first member and a second member made of magnetic material. The first member has a plurality of first claws arranged in a comb-like pattern. The second member has a plurality of second claws arranged in a comb-like pattern. The plurality of first claws and the plurality of second claws are alternately arranged on a surface facing the magnetic ring. The first member and the second member have the same shape. [Effects of the Invention]

[0009] In the bearing device or spacer disclosed herein, the two magnetic rings are made into parts of the same shape, which means that only one type of mold is required for press molding, thereby reducing initial manufacturing costs and eliminating the need to change molds when manufacturing the magnetic rings, thereby reducing manufacturing costs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view of a bearing device according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing a schematic configuration of a generator G. [Figure 3]FIG. 2 is a side view of the magnetic ring member 10. [Figure 4] FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] FIG. 1 is a diagram showing a state in which two magnetic ring members 10 of the same shape are arranged opposite each other. [Figure 6] FIG. 2 is a diagram showing a state in which two magnetic ring members 10 are fitted together. [Figure 7] 7 is a cross-sectional view of the two magnetic ring members after fitting them together, taken along line VII in FIG. 6. FIG. [Figure 8] 2 is a diagram showing the configuration of a circuit board 14. FIG. [Figure 9] FIG. 9 is a diagram showing an improved example of the circuit board 14 of FIG. [Figure 10] FIG. 2 is a cross-sectional view of a bearing device 1A according to a first modified example of the first embodiment. [Figure 11] 10A and 10B are diagrams illustrating the conditions for fitting the recessed portion 10c and the protruding portion 10d together. [Figure 12] FIG. 10 is a diagram showing the phases for alternately fitting grooves 10a and claws 10b. [Figure 13] FIG. 10 is a diagram showing another example in which the number n of grooves 10a and claws 10b is an odd number. [Figure 14] FIG. 10 is a cross-sectional view of a bearing device 1B according to a second modification of the first embodiment. [Figure 15] FIG. 10 is a side view of a magnetic ring member 10A used in the second embodiment. [Figure 16] 16 is a view of the magnetic ring member 10A shown in FIG. 15 as viewed from the arrow XVI. [Figure 17] The figure shows two magnetic ring members 10A of the same shape arranged opposite each other. [Figure 18] This shows the state in which two magnetic ring members 10A are fitted together. [Figure 19] FIG. 2 is a cross-sectional view of the stator taken along a plane including the rotation axis. [Figure 20] FIG. 10 is a cross-sectional view of the stator in another plane including the rotation axis. [Figure 21] 1 is a cross-sectional view showing a schematic configuration in which a stator structure of a claw-pole generator is applied to a bearing device of a spindle device. [Figure 22] FIG. 22 is an enlarged view of the main part on the left side of FIG. 21. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0012] [Embodiment 1] FIG. 1 is a cross-sectional view of a bearing device of embodiment 1 taken along a plane including the rotating shaft. The bearing device 1 shown in FIG. 1 is exemplified by a bearing with a wireless sensor. The bearing device 1 includes a bearing B, an outer ring 7, a magnetic ring 8, and a stator 9. The bearing B includes an outer ring 2, an inner ring 3, rolling elements 4, a cage 5, and a seal 6. The outer ring 7 is fixed to the inner diameter surface of the outer ring 2. The magnetic ring 8 is fixed to the outer diameter surface of the inner ring 3. The stator 9 is fixed to the inner diameter surface of the outer ring 7 so as to face the magnetic ring 8.

[0013] The magnetic ring 8 and the stator 9 constitute a generator G. The generator G is a claw-pole generator. The bearing B is, for example, a deep groove ball bearing with balls as the rolling elements 4, and here we will explain an inner ring rotating type as an example, in which the inner ring 3 is the rotating ring and the outer ring 2 is the fixed ring.

[0014] The magnetic ring 8 includes a core 8a and a multi-pole magnet 8b. The multi-pole magnet 8b is made by vulcanizing and bonding a magnetic material, for example, a mixture of magnetic powder and rubber, to the core 8a, and then magnetizing the magnet with alternating north and south poles. The multi-pole magnet 8b is fixed to the inner ring (rotating ring) 3.

[0015] Stator 9 includes two identically shaped magnetic ring members 10-1 and 10-2, a bobbin 11, and a coil 12. The coil 12 is wound multiple times in the circumferential direction of bobbin 11. While an example using bobbin 11 is shown here, a stator can also be configured in the same way using a coil that does not use bobbin 11.

[0016] A resin case 13 is fixed to the inner diameter surface of the outer ring 7 so as to be adjacent to the generator G. A circuit board 14 is fixed to the case 13. The circuit board 14 is equipped with a power supply circuit 15 that rectifies the AC power generated by the generator G to convert it to DC, a sensor 16 that monitors the condition of the bearing B, and a wireless communication circuit 17 that wirelessly transmits the output of the sensor 16 to the outside. An end 12a, which is the winding start point of the coil 12, and an end 12b, which is the winding end point of the coil 12, are connected to the circuit board 14. When the inner ring 3 rotates, the AC power output from the generator G is converted to DC by the power supply circuit 15. A lid 18 that protects the circuit board 14 is made of a non-magnetic insulator such as resin and is fixed to the outer ring 7, for example. Instead of the lid 18, the surface of the circuit board 14 may be sealed with a resin molding compound.

[0017] The circuit board 14 on which the wireless communication circuit 17 is mounted is surrounded by a non-magnetic insulator such as resin. No magnetic material or conductors are arranged on the lid 18 side of the circuit board 14, so wireless communication is possible.

[0018] In addition, case 13 is interposed between bearing B and circuit board 14. Although bearing B may become hot due to friction during rotation, if case 13 is made of a resin material with low thermal conductivity, it is possible to suppress the temperature rise of circuit board 14. For example, using a material with excellent heat insulation properties, such as resin containing fine bubbles, is effective in suppressing the temperature rise.

[0019] Although the seal 6 is not mounted on the side of the bearing B where the magnetic ring 8 is fixed, narrowing the gaps between the magnetic ring 8 and the stator 9, case 13, and other components will create a labyrinth seal (non-contact seal) structure, preventing the intrusion of foreign matter, etc. If necessary, to improve the sealing characteristics, a groove or the like may be provided on one of the opposing surfaces, or a contact-type seal may be provided.

[0020] FIG. 2 shows the schematic configuration of generator G. Generator G is a claw-pole generator. The magnetic rotor is composed of a ring-shaped multi-pole magnet 8b. The stator 9 is composed of a coil 12 and a magnetic yoke surrounding it. The magnetic yoke is composed of magnetic ring members 10-1 and 10-2. The magnetic flux emitted from the north pole of multi-pole magnet 8b enters the magnetic yoke through claw 10b, which is a magnetic pole, circulates around the coil, and enters the south pole of multi-pole magnet 8b through claw 10b, which is an adjacent magnetic pole. When the positions of the north and south poles of multi-pole magnet 8b are swapped depending on the rotation angle of the magnetic rotor, the direction of the magnetic flux is reversed. The alternating magnetic field generated in this way generates an AC voltage across both ends of coil 12.

[0021] Fig. 3 is a side view of the magnetic ring member 10. Fig. 4 is a cross-sectional view taken along the line IV-IV in Fig. 3. Referring to Figs. 3 and 4, grooves 10a and claws 10b opening in the axial direction are alternately arranged in a comb-like pattern at one end of the magnetic ring member 10.

[0022] A recess 10c and a protrusion 10d are formed on the end surface 10f of the magnetic ring member 10. When two identically shaped magnetic ring members 10-1 and 10-2 are placed opposite each other with the claws 10b alternately arranged, the positions of the recess 10c and the protrusion 10d are designed so that the protrusion 10d of one magnetic ring member 10-2 is positioned relative to the recess 10c of the other magnetic ring member 10-1.

[0023] At least one recess 10c and one protrusion 10d is sufficient, but multiple recesses 10c and multiple protrusions 10d may be provided as shown in Fig. 3. For example, assembly is possible if the protrusion 10d shown in circle V1 and the recess 10c shown in circle V2 in Fig. 3 are formed. However, in this embodiment, two recesses 10c and two protrusions 10d are formed in Fig. 3, taking into consideration balance during assembly.

[0024] Furthermore, a hole 10e is provided on the side surface of the magnetic ring member 10 for drawing out the ends 12a and 12b of the coil 12 to the outside.

[0025] FIG. 5 is a diagram showing a state in which two magnetic ring members 10 of the same shape are arranged opposite each other.

[0026] In reality, a bobbin 11 around which a coil 12 is wound is housed in the space sandwiched between the two magnetic ring members 10-1 and 10-2, but to avoid complicating the drawing, the bobbin 11 around which the coil 12 is wound is omitted here.

[0027] The total number of magnetized poles, including the north and south poles, of the magnetic ring 8 is the same as the number of claws 10b in the state shown in FIG.

[0028] Fig. 6 is a diagram showing the state in which two magnetic ring members 10 are fitted together. Fig. 7 is a cross-sectional view of part VII in Fig. 6 after the two magnetic ring members have been fitted together, taken along a plane including the rotation axis of the bearing. Note that the bobbin 11 and the coil 12 are arranged inside the stator in the same manner as in Fig. 1 etc., but are omitted from Fig. 7.

[0029] Two magnetic ring members 10-1 and 10-2 of the same shape are used. The recesses 10c and protrusions 10d on the end faces 10f of the magnetic ring members 10 are fitted together so that the claws 10b on each magnetic ring member 10 are alternately arranged.

[0030] The same number of recesses 10c and protrusions 10d are formed on the end face 10f of the magnetic ring member 10. By fitting the recesses 10c and protrusions 10d together so that the end faces 10f abut against each other, it becomes easy to align the arrangement phase so that the gaps between the claws 10b of each magnetic ring member 10 are uniform. Furthermore, because multiple recesses 10c and protrusions 10d are arranged in the circumferential direction, the magnetic ring members 10 can be fixed in position without shifting circumferentially.

[0031] The end faces 10f of the two magnetic ring members 10 abut against each other without any gaps, forming a magnetic path, but even if a gap does form, if the outer ring 7 is made of a magnetic material, the outer ring 7 can be used as a magnetic path, so the magnetic resistance of the magnetic yoke can be kept small.

[0032] By making the two magnetic ring members 10-1 and 10-2 parts of the same shape, only one type of mold is required for press molding, which helps to keep initial manufacturing costs low.In addition, when manufacturing the magnetic rings, the number of steps required to change molds is reduced, which helps to keep manufacturing costs down.

[0033] Furthermore, by providing the recessed portion 10c and the protruding portion 10d, it becomes easier to align the phases of the two magnetic rings during assembly, and the gaps between the claws 10b can be uniformly arranged, making assembly easier.

[0034] Furthermore, the recesses 10c and protrusions 10d provided on the two magnetic ring members 10 are fitted together, so the two magnetic ring members 10 can be easily assembled without adhesive or welding.

[0035] To further strengthen the fit, the mating portions may be subjected to additional plastic processing such as crimping (not shown), or the mating portions may be elastically deformed. By firmly fitting the two magnetic ring members 10 in this manner, the magnetic resistance at the mating portions is further reduced, thereby improving power generation performance.

[0036] 2 to 7, the two opposing magnetic ring members 10-1 and 10-2 have substantially the same outer diameter, which allows the end faces 10f to abut firmly, reducing magnetic resistance. Furthermore, the lack of steps on the outer diameter facilitates assembly work, such as inserting the stator 9 into the outer ring 7.

[0037] The magnetic ring member 10 is generally manufactured by press-molding a thin magnetic plate in a mold, but it can also be manufactured by injection molding a resin material and then depositing the magnetic material on the surface by plating, electrodeposition, etc. This manufacturing method makes it easy to manufacture even fine claw shapes that are difficult to process by pressing.

[0038] This manufacturing method also requires only one type of injection mold, making it possible to reduce initial manufacturing costs.

[0039] 8 is a diagram showing the configuration of circuit board 14. Mounted on circuit board 14 are power supply circuit 15, sensor 16, and wireless communication circuit 17. Power supply circuit 15 smoothes AC power obtained from generator G to convert it to DC, and then boosts or lowers the voltage in a subsequent stage to generate DC power supply GV for driving sensor 16 and wireless communication circuit 17. The frequency of the AC signal obtained from generator G changes depending on the rotational speed of inner ring 3, so the AC signal can be processed in rotation detection unit 20 to obtain rotation signal RP.

[0040] For example, if an AC signal is half-wave rectified by a diode and input to the base of a transistor, a rotation pulse signal corresponding to the rotation speed can be obtained, making it possible to detect the rotation speed. The rotation detection unit 20 may be such a transistor.

[0041] The sensor 16 is, for example, a temperature sensor or an acceleration sensor that monitors the condition of the bearing B. In Fig. 1, the sensor 16 is mounted on the circuit board 14, but the temperature sensor may be attached to or in the vicinity of the outer ring 2 so as to directly measure the temperature of the bearing B, and the sensor signal may be input to the circuit board 14.

[0042] Wireless communication circuit 17 includes input unit 17a that receives a sensor signal, calculation unit 17b that processes the sensor signal, transmission / reception unit 17c that transmits and receives data, and antenna 17d. For example, if the sensor output is an analog voltage, input unit 17a may include a DA converter. By converting the sensor output to a digital signal in the vicinity of sensor 16 with this configuration, it is possible to suppress the intrusion of electromagnetic noise.

[0043] The calculation unit 17b has a CPU (Central Processing Unit) function and a memory function, and performs calculation processing on the information obtained from the sensor 16.

[0044] The wireless communication circuit 17 is a module that complies with wireless standards such as Bluetooth (registered trademark) or Bluetooth Low Energy (registered trademark). When the amount of power generated is low, it is preferable that the wireless communication circuit 17 be a circuit that can be driven with low power. Note that the wireless communication circuit 17 may also be a communication circuit that complies with a wireless standard other than those listed above.

[0045] It is expected that the presence of magnetic materials near antenna 17d will affect wireless communication. However, in this embodiment, circuit board 14 is fixed via case 13 made of a non-magnetic material, which allows a large distance to be maintained between antenna 17d and magnetic materials such as stator 9, thereby reducing the effect on wireless communication. Furthermore, if stator 9 is not located on the back side of wireless communication circuit 17, the effect on wireless communication can be further reduced.

[0046] The signal from sensor 16 may be processed by calculation unit 17b into an index according to the purpose, such as an average value calculated by calculation unit 17b, or maximum and minimum values ​​within a certain period of time, and then transmitted. By processing the signal from sensor 16 in calculation unit 17b, the amount of data to be transmitted can be reduced, the number of communications can be reduced, and power consumption can be suppressed.

[0047] FIG. 9 is a diagram showing an improved example of the circuit board 14 of FIG. 8. When using a generator G that utilizes the rotation of the inner ring 3, the necessary power cannot be secured unless the inner ring 3 rotates at a certain speed or higher. For this reason, FIG. 9 includes a battery 21 in addition to the generator G. With this configuration, if the necessary power cannot be secured by the generator G, a switch 19 may be used to switch to battery drive. Alternatively, the output of the generator G may be stored in the battery 21, and data may be transmitted intermittently after waiting for a sufficient amount of power to be stored.

[0048] In this way, even when the inner ring 3 is rotating at a low speed or is stopped, the signal of the sensor 16 can be transmitted, so that the bearing B can be monitored at all times.

[0049] [First Modification of First Embodiment] Figure 10 is a cross-sectional view of a plane including the rotating shaft of bearing device 1A according to Variation 1 of Embodiment 1. Bearing device 1A is a bearing with a wireless sensor that is an improved example of the bearing device shown in Figure 1. In Figure 10, case 13 is arranged so as to be inserted into the inner diameter portion of magnetic ring 8, and circuit board 14 is arranged inside this, making it possible to reduce the axial width compared to Figure 1 and make the device more compact.

[0050] FIG. 11 is a diagram illustrating the conditions for fitting the recessed portions 10c and the protruding portions 10d of the two magnetic ring members 10 together.

[0051] For simplicity of illustration, the recessed portions 10c are indicated by white circles, and the protruding portions 10d are indicated by hatched circles.

[0052] 11(a) is a view of the magnetic ring member 10-1 as seen from the recessed portion 10c and protruding portion 10d side, showing an example in which one recessed portion 10c and one protruding portion 10d are formed. The recessed portion 10c is formed at a position θ from the reference position, and the protruding portion 10d is formed at a position φ from the recessed portion 10c.

[0053] Figure 11(b) is a diagram showing the arrangement of the magnetic ring member 10-2. The arrangement of the magnetic ring member 10-2 corresponds to Figure 11(a) rotated clockwise by an angle α so as to be symmetrical with respect to line O. When bent along line O, the recess 10c on the magnetic ring member 10-1 fits into the protrusion 10d on the magnetic ring member 10-2, and the recess 10c on the magnetic ring member 10-2 fits into the protrusion 10d on the magnetic ring member 10-1.

[0054] In order for the recessed portion 10c and the protruding portion 10d to fit together, the following formula (1) must be satisfied. α=2π-2θ-φ …(1) FIG. 12 shows the phases of two magnetic ring members 10 so that the grooves 10a and claws 10b fit alternately. FIG. 12(a) shows the arrangement of the grooves and claws of the magnetic ring member 10-1. FIG. 12(b) shows the arrangement of the grooves and claws of the magnetic ring member 10-1. The state shown in FIG. 12(b) corresponds to a state rotated by an angle α from the state shown in FIG. 12(a).

[0055] When bent along line O, in order for the grooves 10a and the claws 10b to alternately fit together, the relationship shown in the following formula (2) must be satisfied. α=(i+1 / 2)·2π / n …(2) In the above, i is an integer indicating the number of pitches to be shifted when mating, n is the number of grooves 10a and claws 10b of the magnetic ring member 10, and 2π / n is the claw pitch P. In order to shift the claws by 1 / 2 pitch so that they are alternately arranged, 1 / 2 is added to i in equation (2).

[0056] Since α in equation (1) is equal to α in equation (2), solving these equations for i gives the following equation (3). i=n / 2π(2π−2θ−φ−π / n) …(3) That is, the positions of the recessed portions 10c and the protruding portions 10d can be determined by selecting φ so that the right-hand side of equation (3) is an integer for the number n of grooves 10a and claws 10b. For example, assuming θ=π / 6, φ=π / 2, and n=6, i=3.

[0057] Fig. 13 is a diagram showing another example in which the number n of grooves 10a and claws 10b is an odd number. In the example shown in Fig. 13, assuming that θ=π / 9, n=9, and φ=5π / 9, i=5.

[0058] [Modification 2 of Embodiment 1] In the above embodiment, an example has been shown in which the outer ring 2 of bearing B is fixed to a stationary member and the inner ring 3 is fixed to a rotating member, and the rotating member is supported relative to the stationary member, but the present invention can also be applied to cases in which the outer ring rotates and the inner ring is stationary.

[0059] Fig. 14 is a cross-sectional view taken along a plane including the rotating shaft of bearing device 1B according to modified example 2 of embodiment 1. Bearing device 1B is a modified example of bearing device 1A shown in Fig. 10, and is a bearing with a wireless sensor that rotates on the outer ring.

[0060] In Figure 14, magnetic ring 8 is fixed to the inner diameter portion of outer ring 2, and multi-pole magnet 8b is formed on the inner diameter side of core metal 8a. Ring member 30 is fixed to the outer diameter surface of inner ring 3, which serves as the fixed ring. Stator 9 is fixed to the outer diameter side of ring member 30, and case 13 is fixed to the inner diameter side. In Figure 14, the outer periphery of stator 9 faces magnetic ring 8, so the pawls arranged in a comb-like pattern are arranged on the outer periphery of stator 9.

[0061] The case 13 has a flange portion 30a that protrudes radially outward. A labyrinth structure is formed by narrowing the gap between the flange portion 30a and the magnetic ring 8. The labyrinth structure prevents the intrusion of foreign matter.

[0062] A circuit board 14 is fixed in a groove provided in the case 13. Mounted on the circuit board 14 are a power supply circuit 15 that rectifies the AC power generated by the generator G and converts it to DC, a sensor 16 that monitors the condition of the bearing B, and a wireless communication circuit 17 that wirelessly transmits the output of the sensor 16 to the outside. A winding start end 12a and a winding end end 12b drawn out from the coil 12 are connected to the circuit board 14. The AC power output from the generator G when the outer ring 2 rotates is converted to DC by the power supply circuit 15. A lid 18 that protects the circuit board 14 is made of a non-magnetic insulator such as resin and closes the opening of the case 13. Instead of the lid 18, the surface of the circuit board 14 may be sealed with a resin molding compound.

[0063] Even if the rotating ring is the outer ring 2, the structure shown in FIG. 14 allows the axial width to be reduced, making it compact.

[0064] [Embodiment 2] In the first embodiment, an example of forming a magnetic ring by combining two magnetic ring members of the same shape is shown. In the second embodiment, another example of forming a magnetic ring by combining two magnetic ring members of the same shape is shown. The parts other than the magnetic ring are the same as the configuration described in the first embodiment, so only the magnetic ring will be described below.

[0065] Fig. 15 is a side view of the magnetic ring member 10A used in embodiment 2. Fig. 16 is a view taken along the arrow XVI of the magnetic ring member 10A shown in Fig. 15.

[0066] 15 and 16, grooves 10a and claws 10b opening in the axial direction are alternately arranged in a comb-like pattern at one end of the magnetic ring member 10A. A plurality of large diameter portions 10g and small diameter portions 10h with different outer diameters are formed at the other end. The number of large diameter portions 10g is equal to the number of small diameter portions 10h. A notch 10j is provided at the boundary between the large diameter portions 10g and the small diameter portions 10h. FIG. 15 shows an example in which two large diameter portions 10g and two small diameter portions 10h are arranged.

[0067] Fig. 17 shows two magnetic ring members 10A of the same shape arranged opposite each other, and Fig. 18 shows two magnetic ring members 10A fitted together.

[0068] When two identical magnetic ring members 10A-1 and 10A-2 are placed opposite each other with their claws 10b alternately arranged, the large diameter portion 10g of the magnetic ring member 10A-1 fits into the small diameter portion 10h of the magnetic ring member 10A-2, and the small diameter portion 10h of the magnetic ring member 10A-1 fits into the large diameter portion 10g of the magnetic ring member 10A-2.

[0069] When the two magnetic ring members 10A, 10A are fitted together, by aligning the respective notched portions 10j, the respective claws 10b are arranged with a certain gap between them without contacting each other.

[0070] A hole 10e provided on the side surface of the magnetic ring member 10 is formed for drawing out the ends 12a and 12b of the coil 12 to the outside.

[0071] In reality, a bobbin 11 wound with a coil 12 is housed in the space sandwiched between the two magnetic ring members 10A-1 and 10A-2. However, to avoid complicating the illustration, the bobbin 11 wound with the coil 12 is omitted here.

[0072] The total number of magnetized poles, including the north and south poles, of the magnetic ring 8 is the same as the number of claws 10b in the state shown in FIG.

[0073] Fig. 19 is a cross-sectional view of portion XIX of the stator of Fig. 18 taken on a plane including the rotation axis. Fig. 20 is a cross-sectional view of portion XX of the stator of Fig. 18 taken on another plane including the rotation axis. Note that the bobbin 11 and the coil 12 are arranged inside the stator in the same manner as in Fig. 1 etc., but are omitted from Figs. 19 and 20.

[0074] The claws 10b of the magnetic ring member 10A-1 and the claws 10b of the magnetic ring member 10A-2 are arranged on one side of the coil 12 (top in FIGS. 19 and 20), and in a cross section in a certain plane (FIG. 20), the first member 10A-1 and the second member 10A-2 overlap in the order of the small diameter portion 10h of the first member 10A-1 and the large diameter portion 10g of the second member 10A-2, in a direction away from the coil, on one side and the opposite side of the coil (bottom in FIG. 20). Also, in a cross section in another plane (FIG. 19), the first member 10A-1 and the second member 10A-2 overlap in the order of the small diameter portion 10h of the second member 10A-2 and the large diameter portion 10g of the first member 10A-1, in a direction away from the coil, on one side and the opposite side of the coil (bottom in FIG. 19).

[0075] In this way, the large diameter portion 10g of the magnetic ring member 10A-1 is fitted into the small diameter portion 10h of the magnetic ring member 10A-2, and the large diameter portion 10g of the magnetic ring member 10A-2 is fitted into the small diameter portion 10h of the magnetic ring member 10A-1, so that the claws 10b on the magnetic ring member 10A-1 and the claws 10b on the magnetic ring member 10A-2 are arranged alternately.

[0076] Because the large-diameter portion 10g and the small-diameter portion 10h abut on each other via cylindrical surfaces, the magnetic ring member 10A-1 and the magnetic ring member 10A-2 can be held in place without shifting in the circumferential direction, and magnetic resistance can be reduced. Furthermore, because the same number of large-diameter portions 10g and small-diameter portions 10h are formed, aligning the positions of the notches 10j allows the large-diameter portions 10g and the small-diameter portions 10h to fit together, and the gaps between the claws 10b of the magnetic ring member 10A-1 and the claws 10b of the magnetic ring member 10A-2 become uniform. This facilitates phase alignment between the magnetic ring member 10A-1 and the magnetic ring member 10A-2 when assembling the stator 9.

[0077] Furthermore, by making the two magnetic ring members 10A-1 and 10A-2 parts of the same shape, only one type of die is required for press molding, which reduces the initial manufacturing cost. Also, by eliminating the need to change dies when manufacturing the magnetic rings, manufacturing costs can be reduced.

[0078] Furthermore, by providing a large diameter portion 10g and a small diameter portion 10h and fitting them together, the contact area is increased, reducing magnetic resistance, and the gaps between the claws 10b can be uniformly arranged, making assembly easier.

[0079] When the magnetic ring member 10A is press-molded, the outer diameters of the two magnetic ring members 10A-1 and 10A-2 to be fitted together are approximately the same, so that the difference in outer diameter when they are fitted together can be reduced, making the assembly work of inserting the stator 9 into the outer ring 7 easier.

[0080] [Embodiment 3] The stator structure of a claw-pole generator can be applied not only to bearings but also to outer ring spacers. In the third embodiment, an example will be described in which the stator structure of a claw-pole generator is applied to an outer ring spacer of a spindle device.

[0081] Fig. 21 is a cross-sectional view showing a schematic configuration in which the stator structure of a claw-pole generator is applied to a bearing device for a spindle device. Fig. 22 is an enlarged view of the main part on the left side of Fig. 21. Fig. 22 mainly shows bearing device 90.

[0082] 21 is used, for example, as a built-in motor type spindle device for a machine tool. In this case, a motor 52 is built into one end of a spindle 51 supported by the spindle device 50 for the machine tool main spindle, and a cutting tool such as an end mill (not shown) is connected to the other end.

[0083] 21 and 22, spindle device 50 includes bearings 53a and 53b, a spacer 54 disposed adjacent to bearings 53a and 53b, motor 52, and a bearing 55 disposed adjacent to motor 52 on the opposite side of spacer 54. Main shaft 51 is rotatably supported by a plurality of bearings 53a and 53b provided in housing 57 embedded in the inner diameter portion of outer cylinder 56.

[0084] The bearing 53a includes an inner ring 53ia, an outer ring 53ga, rolling elements Ta, and a cage Rta. The bearing 53b includes an inner ring 53ib, an outer ring 53gb, rolling elements Tb, and a cage Rtb. The spacer 54 includes an inner ring spacer 54i and an outer ring spacer 54g.

[0085] In order to enable wireless communication, which will be described later, it is preferable that the rolling elements Ta and Tb are ceramic balls, which are non-metallic insulators, and that the cages Rta and Rtb are made of resin.

[0086] An inner ring 53ia of bearing 53a and an inner ring 53ib of bearing 53b, which are spaced apart in the axial direction, are tightly fitted (press-fitted) onto main shaft 51. An inner ring spacer 54i is disposed between inner rings 53ia and 53ib, and an outer ring spacer 54g is disposed between outer rings 53ga and 53gb.

[0087] Bearings 53a and 53b 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. Angular contact ball bearings are used in bearing device 90 shown in Fig. 22, and the two bearings 53a and 53b are installed in a back-to-back configuration (DB configuration).

[0088] The outer ring spacer 54g is divided into two in the axial direction, a first outer ring spacer 54g1 and a second outer ring spacer 54g2, with the stator 9 of the generator G fixed between them. A magnetic ring 8 is fixed to the outer peripheral surface of the inner ring spacer 54i, and the stator 9 and the multi-pole magnets 8b of the magnetic ring 8 are arranged to face each other with a gap between them, thereby forming the generator G. The claw-pole generators shown in Figs. 2 to 7 and 15 to 20 can be used as the generator G.

[0089] The magnetic ring 8 includes a core 8a and a multi-pole magnet 8b. The multi-pole magnet 8b is made by vulcanizing and bonding a magnetic material, for example, a mixture of magnetic powder and rubber, to the core 8a, and then magnetizing the magnet with alternating north and south poles. The multi-pole magnet 8b is fixed to the inner ring spacer 54i.

[0090] Stator 9 includes two identically shaped magnetic ring members 10-1 and 10-2, a bobbin 11, and a coil 12. The coil 12 is wound multiple times in the circumferential direction of bobbin 11. While an example using bobbin 11 is shown here, a stator can also be configured in the same way using a coil that does not use bobbin 11.

[0091] A groove 54g1a is formed on the end face of the first outer ring spacer 54g1, and the circuit board 14 is mounted inside the groove 54g1a.

[0092] Mounted on the circuit board 14 are a power supply circuit 15 that rectifies AC power generated by the generator G and converts it to DC, a sensor 16 that monitors the status of the bearing device 90, and a wireless communication circuit 17 that wirelessly transmits the output of the sensor 16 to the outside. End 12a, where the winding begins, and end 12b, where the winding ends, of the coil 12 are connected to the circuit board 14 through a hole 54g1b. After wiring, the hole 54g1b is preferably sealed with a sealant to prevent oil and other contaminants from entering the circuit board 14. When the main shaft 51 rotates, the AC power output from the generator G is converted to DC by the power supply circuit 15. The cover 18 that protects the circuit board 14 is made of a nonmetallic insulator such as resin and is fixed inside the groove 54g1a. Instead of the cover 18, the surface of the circuit board 14 may be sealed with a resin molding compound.

[0093] A plurality of sensors such as a temperature sensor, an acceleration sensor, and a load sensor are implemented as the sensor 16. For example, when a load sensor (not shown) is implemented, the load sensor (not shown) is placed between the first outer ring spacer 54g1 and the second outer ring spacer 54g2, and the signal is processed on the circuit board 14 and the output is transmitted wirelessly.

[0094] Single-row rolling bearing 55 is a cylindrical roller bearing. Bearings 53a and 53b, which are angular contact ball bearings, support radial and axial loads acting on spindle device 50. Single-row bearing 55, which is a cylindrical roller bearing, supports radial loads acting on spindle device 50 for a machine tool main shaft.

[0095] A coolant flow path GV is formed in the housing 57. By flowing a coolant between the housing 57 and the outer cylinder 56, the bearings 53a and 53b can be cooled.

[0096] If grease-lubricated bearings are used as the bearings 53a and 53b, no lubricating oil supply passage is required, but if lubrication with air oil or the like is required, a lubricating oil supply passage is provided in the outer ring spacer 54g. Note that the lubricating oil supply passage is not shown here.

[0097] During assembly, bearing 53a, spacer 54, bearing 53b, and spacer 58 are first inserted into main shaft 51 in this order, and an initial preload is applied by tightening nut 59. Then, main shaft 51, to which bearings 53a and 53b are attached, is inserted into housing 57 until the right side of outer ring 53gb of bearing 53b in FIG. 22 abuts on stepped portion 57a ​​provided on housing 57. Finally, front cover 60 presses outer ring 53ga of left-side bearing 53a, thereby fixing main shaft 51 to housing 57.

[0098] By tightening nut 59, a force acts on the end face of inner ring 53ib of bearing 53b via spacer 58, pressing inner ring 53ib toward inner ring spacer 54i. This force is transmitted through inner ring 53ib, rolling element Tb, and outer ring 53gb, applying preload between the raceway surfaces of inner ring 53ib and outer ring 53gb and rolling element Tb, and is also transmitted from outer ring 53gb to outer ring spacer 54g.

[0099] This force is transmitted to outer ring 53ga, rolling element Ta, and inner ring 53ia in bearing 53a, and also applies preload between the raceway surfaces of inner ring 53ia and outer ring 53ga of left-side bearing 5a and rolling element Ta. The preload applied to bearings 53a and 53b is determined by the amount of movement limited by the dimensional difference between the width of outer ring spacer 54g and the width of inner ring spacer 54i, for example.

[0100] 21, inner ring 55a is positioned in the axial direction by a cylindrical member 61 fitted onto the outer periphery of main shaft 51 and an inner ring retainer 62. Inner ring retainer 62 is prevented from coming off by a nut 63 threaded onto main shaft 51. Outer ring 55b of bearing 55 is sandwiched between positioning members 65 and 66 fixed to end member 64. Inner ring 55a slides integrally with end member 64 in response to the expansion and contraction of main shaft 51.

[0101] Motor 52 that drives main shaft 51 is disposed at an axially intermediate position between bearing 53b and single-row bearing 55 in space 67 formed between main shaft 51 and outer cylinder 56. Rotor 68 of motor 52 is fixed to a cylindrical member 61 fitted onto the outer periphery of main shaft 51, and stator 69 of motor 52 is fixed to the inner periphery of outer cylinder 56.

[0102] It should be noted that the coolant flow path for cooling the motor 52 is not shown here.

[0103] The outer ring spacer 54g is equipped with a generator G, a sensor 16, and a wireless communication circuit 17 that wirelessly transmits the output of the sensor 16 to the outside, and is capable of monitoring the operating status of the spindle device 50 and transmitting the sensor output wirelessly. Furthermore, an abnormality determination means (not shown) that determines whether or not there is an abnormality from the output of each sensor may be mounted on the circuit board 14, and the abnormality determination result may be transmitted wirelessly.

[0104] The radio waves transmitted from the wireless communication circuit 17 pass between the outer ring 53ga and the inner ring 53ia of the bearing 53a and are emitted from the gap 70 of the labyrinth seal formed by the main shaft 51 and the front cover 60.

[0105] Because the spindle device 50 communicates wirelessly, there is no need to pull out wires from the outer ring spacer 54g. Therefore, there is no need to machine grooves for wiring on the inner diameter side of the housing 57, and modifications to the spindle device 50 can be kept to a minimum.

[0106] 21 and 22 further include an outer ring spacer 54g and an inner ring spacer 54i. The magnetic ring 8 is fixed to the inner ring spacer 54i, and the stator 9 is fixed to the outer ring spacer 54g so as to face the magnetic ring 8. As a modified example (not shown), the magnetic ring 8 may be fixed to the outer ring spacer 54g, and the stator 9 may be fixed to the inner ring spacer 54i so as to face the magnetic ring 8. In this case, since the outer ring rotates, the circuit board 14 is fixed to the inner ring spacer 54i.

[0107] (summary) Finally, this embodiment will be summarized again with reference to the drawings.

[0108] Referring to FIG. 1, the bearing device 1 includes a magnetic ring 8 fixed to a rotating member and a stator 9 fixed to a non-rotating member so as to face the magnetic ring 8. The magnetic ring 8 and the stator 9 constitute a claw-pole generator G. The stator 9 includes a coil 12 and a magnetic yoke surrounding the coil 12. The magnetic yoke is formed by combining a first member 10-1 and a second member 10-2 made of magnetic material. The first member 10-1 has a plurality of first claws 10b arranged in a comb-teeth pattern, and the second member 10-2 has a plurality of second claws 10b arranged in a comb-teeth pattern. The first member 10-1 and the second member 10-2 have a plurality of first claws 10b arranged alternately on the surface facing the magnetic ring 8. The first member 10-1 and the second member 10-2 have the same shape.

[0109] Preferably, the bearing device 1 further includes an outer ring 2, an inner ring 3, and a plurality of rolling elements 4 arranged between the outer ring 2 and the inner ring 3. The magnetic ring 8 is fixed to either the outer ring 2 or the inner ring 3. The stator 9 is fixed to the other of the outer ring 2 or the inner ring 3 so as to face the magnetic ring 8.

[0110] 21 and 22 preferably further includes an outer ring spacer 54g and an inner ring spacer 54i. The magnetic ring 8 is fixed to the inner ring spacer 54i, and the stator 9 is fixed to the outer ring spacer 54g so as to face the magnetic ring 8. Although not shown, the magnetic ring 8 may be fixed to the outer ring spacer 54g, and the stator 9 may be fixed to the inner ring spacer 54i so as to face the magnetic ring 8.

[0111] In this way, by making the two magnetic ring members 10-1 and 10-2 parts of the same shape, only one type of die is required for press molding, which reduces the initial manufacturing cost. In addition, by eliminating the need to change dies during the manufacture of the magnetic ring members, manufacturing costs can be reduced.

[0112] The stator 9 and magnetic ring 8 have an annular shape through which the rotating shaft of the bearing device 1 passes. In a cross section of the stator 9 taken on a plane including the rotating shaft as shown in Figures 1, 10, 14, etc., the first claws 10b and the second claws 10b are arranged on one side of the coil 12, and the end face 10f of the first member 10-1 and the end face 10f of the second member 10-2 abut on one side and the opposite side of the coil 12 in the cross section.

[0113] A first recess 10c and a first protrusion 10d are formed on an end surface 10f of the first member 10-1, and a second recess 10c and a second protrusion 10d are formed on an end surface of the second member. In a cross section, on one side and the opposite side of the coil 12, the first recess 10c abuts against the second protrusion 10d, and the first protrusion 10d abuts against the second recess 10c, as shown in Figures 6 and 7. Note that the coil 12 surrounded by the first member 10-1 and the second member 10-2 shown in Figure 2 is not shown in Figure 7.

[0114] By providing the recessed portion 10c and the protruding portion 10d in this manner, it becomes easier to align the phases of the two magnetic rings during assembly.

[0115] 11, the first member 10-1 and the second member 10-2 are configured to satisfy α=2π-2θ-φ, where α represents the rotation angle between the first member 10-1 and the second member 10-2, θ represents the angle indicating the position of the first recess 10c from the reference position, and φ represents the angle indicating the position of the first protrusion 10d with the position of the first recess 10c as the starting point.

[0116] The first member 10-1 and the second member 10-2 are configured to satisfy α=(i+1 / 2)·2π / n, where α represents the rotation angle between the first member 10-1 and the second member 10-2. i represents an integer. n represents the number of first claws 10b on the first member 10-1 and the number of second claws 10b on the second member 10-2. 2π / n represents the pitch P of the first claws 10b on the first member 10-1 and the number of second claws 10b on the second member 10-2. For example, FIG. 12 shows an example where n=6 and i=3.

[0117] The stator 9 and the magnetic ring 8 have an annular shape through which the rotating shaft of the bearing device 1 passes. In cross sections of the stator in a first plane and a second plane including the rotating shaft, as shown in Figures 19 and 20, one of the first claws 10b of the first member 10A-1 and one of the second claws 10b of the second member 10A-2 are arranged on one side of the coil 12 (top in Figures 19 and 20), and in the cross section in the first plane (Figure 20), the first member 10A-1 and the second member 10A-2 overlap in this order on one side and the opposite side of the coil (bottom in Figure 20) in a direction away from the coil, and in the cross section in the second plane (Figure 19), the first member 10A-1 and the second member 10A-2 overlap in this order on one side and the opposite side of the coil in a direction away from the coil.

[0118] In this way, the first member 10A-1 and the second member 10A-2 overlap at the portion opposite to the claw 10b, so that the contact area can be increased and the magnetic resistance of the magnetic yoke can be reduced.

[0119] A manufacturing method for manufacturing any of the above-described bearing devices or spacers includes a step of stamping out the first member 10-1 and the second member 10-2 by press working using a mold of the same shape, and a step of assembling the first member 10-1, the second member 10-2, and the coil 12 to form the stator 9.

[0120] In this way, by making the two magnetic ring members 10-1 and 10-2 parts of the same shape, only one type of die is required for press molding, which reduces the initial manufacturing cost. In addition, by eliminating the need to change dies during the manufacture of the magnetic ring members, manufacturing costs can be reduced.

[0121] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention 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]

[0122] 1, 1A, 1B, 90 bearing device, 2, 53ga, 53gb, 55b outer ring, 3, 53ia, 53ib, 55a inner ring, 4, Ta, Tb rolling element, 5, Rta, Rtb cage, 5a, 5b, 53a, 53b, 55, B bearing, 6 seal, 7 outer ring, 8 magnetic ring, 8a core metal, 8b multi-pole magnet, 9, 69 stator, 10, 10-1, 10-2, 10A, 10A-1, 10A-2 magnetic ring member, 10a groove, 10b claw, 10c recess, 10d convex portion, 10e hole, 10f end face, 10g large diameter portion, 10h small diameter portion, 10j notch portion, 11 bobbin, 12 coil, 12a, 12b End, 13 case, 14 circuit board, 15 power supply circuit, 16 sensor, 17 wireless communication circuit, 17a input section, 17b calculation section, 17c transmitting / receiving section, 17d antenna, 18 cover, 19 switch, 20 rotation detection section, 21 battery, 30 ring member, 30a flange section, 50 spindle device, 51 main shaft, 52 motor, 54, 58 spacer, 54g1a groove section, 54g1b hole, 54g1 first outer ring spacer, 54g2 second outer ring spacer, 54g outer ring spacer, 54i inner ring spacer, 56 outer cylinder, 57 housing, 57a step section, 59, 63 nut, 60 front cover, G generator, GV DC power supply.

Claims

1. A bearing device that rotatably supports a rotating member, a magnetic ring fixed to the rotating member; a stator fixed to a non-rotating member so as to face the magnetic ring; the magnetic ring and the stator constitute a claw-pole generator, The stator includes: A coil and a magnetic yoke surrounding the coil; the magnetic yoke is configured by combining a first member and a second member made of a magnetic material, the first member has a plurality of first claws arranged in a comb-teeth shape, the second member has a plurality of second claws arranged in a comb-like shape, the plurality of first claws and the plurality of second claws are alternately arranged on a surface facing the magnetic ring, the first member and the second member have the same shape, the stator and the magnetic ring have an annular shape through which the rotation shaft of the bearing device passes, In a cross section of the stator in a first plane and a second plane including the rotation axis, one of the plurality of first claws and one of the plurality of second claws is disposed on one side of the coil, In a cross section taken along the first plane, the first member and the second member are stacked on each other on the opposite side to the one side of the coil in a direction away from the coil, in that order, the first member and the second member; In a cross section in the second plane, the first member and the second member overlap in the order of the second member and the first member on the opposite side to the one side of the coil, in a direction away from the coil.

2. The outer ring and With inner circle, a plurality of rolling elements disposed between the outer ring and the inner ring; the magnetic ring is fixed to one of the outer ring and the inner ring; The bearing device according to claim 1 , wherein the stator is fixed to the other of the outer ring and the inner ring so as to face the magnetic ring.

3. Outer ring spacer, Further provided with an inner ring spacer, the magnetic ring is fixed to either the outer ring spacer or the inner ring spacer, 2. The bearing device according to claim 1, wherein the stator is fixed to the other of the outer ring spacer and the inner ring spacer so as to face the magnetic ring.

4. A manufacturing method for manufacturing the bearing device according to any one of claims 1 to 3, comprising the steps of: a step of stamping out the first member and the second member by a press process using a die having the same shape; assembling the first member, the second member, and the coil to form the stator.

5. A spacer disposed adjacent to a bearing that rotatably supports a rotating member, Outer ring spacer, Inner ring spacer and a magnetic ring fixed to either the outer ring spacer or the inner ring spacer; a stator fixed to the other of the outer ring spacer and the inner ring spacer so as to face the magnetic ring, the magnetic ring and the stator constitute a claw-pole generator, The stator includes: A coil and a magnetic yoke surrounding the coil; the magnetic yoke is configured by combining a first member and a second member made of a magnetic material, the first member has a plurality of first claws arranged in a comb-teeth shape, the second member has a plurality of second claws arranged in a comb-like shape, the plurality of first claws and the plurality of second claws are alternately arranged on a surface facing the magnetic ring, the first member and the second member have the same shape, the stator and the magnetic ring have an annular shape through which the rotation shaft of the bearing passes, In a cross section of the stator in a first plane and a second plane including the rotation axis, one of the plurality of first claws and one of the plurality of second claws is disposed on one side of the coil, In a cross section taken along the first plane, the first member and the second member are stacked on each other on the opposite side to the one side of the coil in a direction away from the coil, in that order, the first member and the second member; In a cross section taken along the second plane, the first member and the second member overlap in this order on the opposite side to the one side of the coil, in a direction away from the coil.

6. A manufacturing method for manufacturing the spacer according to claim 5, a step of stamping out the first member and the second member by a press process using a die having the same shape; assembling the first member, the second member, and the coil to form the stator.

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