Bearing device

Abstract

To enable a generator to stably and sufficiently supply electric power to a sensor unit in a bearing device in which the sensor unit and the generator are fitted to a self-aligning bearing.SOLUTION: Mutual opposite surfaces of claw-poles 35a, 36c and a magnetic ring 31 of a stator 32 constituting a claw-pole type generator 30 attached to a self-aligning bearing 10 respectively form a spherical surface centered on the center of alignment of the self-aligning bearing 10, and the distance between the claw-poles 35a, 36c and the magnetic ring 31 of the stator 32 remains unchanged and constant even though an inner ring 12 is aligned with an outer ring 11 of the self-aligning bearing 10. Consequently, the generator 30 has no risk of bringing the stator 32 into contact with the magnetic ring 31, and can supply sufficient power to a sensor unit 20 without lowering generation efficiency.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bearing device in which a sensor unit and a generator are attached to a self-aligning roller bearing or a self-aligning ball bearing. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known a bearing device in which a sensor unit for detecting the condition of a rolling bearing and a generator for supplying power to the sensor unit are attached to the rolling bearing.

[0003] In such bearing devices, a sensor unit having sensors such as an acceleration sensor and a temperature sensor and wireless transmission means for transmitting detection data from the sensor to the outside mounted on a substrate is fixed to the fixed race of the outer or inner ring of the rolling bearing (hereinafter also referred to as the "fixed race"), and a magnetic ring that constitutes the generator is often fixed to the rotating race of the outer or inner ring (hereinafter also referred to as the "rotating race"), and a stator is fixed to the fixed race.

[0004] For example, Patent Document 1 discloses a bearing device in which, as shown in FIG. 7, a deep groove ball bearing 50 has balls 53 as rolling elements arranged between an outer ring 51, which is a fixed ring, and an inner ring 52, which is a rotating ring, and at one axial end thereof, an extension portion 51a is provided which protrudes in an annular shape axially outward from the outer periphery of the outer ring 51, and a sensor unit 60 and a generator 70 are provided on the inner periphery of the extension portion 51a.

[0005] In this bearing device, an annular yoke member 72 with an L-shaped cross section that constitutes a stator 71 of a generator 70 is fixed to the inner circumference of the extension part 51a of the outer ring 51, and a substrate (not shown) equipped with a sensor, a wireless transmission means, etc. is attached to the axially inner surface of the yoke member 72, and the substrate and a part of the yoke member 72 constitute a sensor unit 60. A magnetic ring (tone ring) 73 is fixed to one end of the inner ring 52, and a pole piece 74 is provided on the yoke member 72 so as to face the magnetic ring 73 with an air gap (small gap) in the radial direction to form a stator 71, and the stator 71 and the magnetic ring 73 constitute a generator 70. The pole piece 74 is formed by fixing a permanent magnet 75 and a magnetic body 76 facing the magnetic ring 73 to the axially inner surface of the yoke member 72, and winding a coil 77 around the outer circumference of the magnetic body 76. Electric power generated in the pole piece 74 as the magnetic ring 73 rotates is supplied to the sensor unit 60. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-307435 A Summary of the Invention [Problem to be solved by the invention]

[0007] In a bearing device in which a sensor unit and generator are attached to a deep groove ball bearing as in Patent Document 1 above, or in a bearing device in which the deep groove ball bearing is replaced with a cylindrical roller bearing, the positional relationship between the generator stator and the magnetic ring is kept approximately the same during use.

[0008] However, in a bearing device in which a sensor unit and generator are attached to a self-aligning roller bearing or self-aligning ball bearing (hereinafter collectively referred to as a "self-aligning bearing") in the same manner as described above, the fixed ring and rotating ring of the self-aligning bearing will tilt relative to each other due to the aligning operation, changing the distance between the stator fixed to the fixed ring and the magnetic ring fixed to the rotating ring, which may result in insufficient power being obtained. There is also a concern that the stator and magnetic ring may come into contact and be damaged.

[0009] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a bearing device in which a sensor unit and a generator are attached to a self-aligning bearing, whereby the generator can stably supply sufficient power to the sensor unit. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a self-aligning bearing having an outer ring with a spherical raceway on its inner circumference, an inner ring with double-row raceway grooves on its outer circumference, and double-row rolling elements arranged to roll freely between the spherical raceway of the outer ring and each raceway groove of the inner ring, a sensor unit fixed to the fixed raceway of the outer ring and the inner ring, and a generator for supplying power to the sensor unit, the generator comprising a magnetic ring arranged to be rotatable integrally with the rotating raceway of the outer ring and the inner ring, and an annular stator facing the magnetic ring with an air gap in the radial direction and fixed to the fixed raceway, the opposing surfaces of the stator and the magnetic ring being formed into a spherical surface centered on the center of the self-aligning bearing (Configuration 1). Here, "radial direction" means the radial direction forming the spherical raceway of the outer ring. Also, the "center of centering" is the center of the spherical surface of the inner circumference of the outer ring.

[0011] By using the bearing device of configuration 1, even if the fixed side raceway (fixed raceway) and the rotating side raceway (rotating raceway) of the self-aligning bearing are tilted (aligned) relative to each other, the distance between the stator and magnetic ring of the generator remains constant, so there is no risk of contact between the stator and magnetic ring, and the generator can stably supply sufficient power to the sensor unit.

[0012] In the above configuration 1, when the stator of the generator contains a bobbin around which a coil is wound, it is preferable that the inner peripheral surface of the bobbin is formed into a spherical surface along the surface of the stator facing the magnetic ring (configuration 2). In this way, compared to a case where the inner peripheral surface of the bobbin is formed into a cylindrical surface, the space in which the coil of the generator can be wound is larger, and the number of turns of the coil can be increased to improve power generation performance.

[0013] In the above configuration 1 or 2, when the inner ring is a rotating raceway ring, if the outer diameter of one of the shoulders on both axial sides of the inner ring is formed smaller than the outer diameter of the other shoulder, and the magnetic ring is attached to the outer periphery of an extension that protrudes annularly axially outward from the inner circumference of that one shoulder (configuration 3), then compared to a configuration in which the outer diameters of the shoulders on both axial sides of the inner ring are formed to be the same, the position of the generator can be moved radially inward, and the radial dimension of the sensor unit can be increased by that amount, making it easier to mount sensors and electronic circuit components on a board built into the sensor unit. Effect of the Invention

[0014] As described above, the bearing device of this invention has the opposing surfaces of the stator and magnetic ring of the generator attached to the self-aligning bearing formed as spherical surfaces centered on the alignment center of the self-aligning bearing.Therefore, even if the fixed ring and rotating ring of the self-aligning bearing are aligned, the distance between the stator and magnetic ring is maintained constant, and the generator can steadily supply sufficient power to the sensor unit. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a longitudinal sectional front view of a bearing device according to an embodiment of the present invention; [Diagram 2] Left side view of Figure 1 [Diagram 3] FIG. 2 is an exploded perspective view of the bearing device of FIG. 1; [Figure 4] FIG. 2 is an enlarged longitudinal front view of the main part of FIG. 1; [Diagram 5] A longitudinal sectional front view showing an enlarged view of the generator and its surroundings in FIG. [Figure 6] FIG. 5 is a longitudinal sectional front view showing a modification of the generator position corresponding to FIG. 4; [Figure 7] FIG. 1 is a longitudinal sectional front view of a main portion of a conventional bearing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to Figures 1 to 6. As shown in Figures 1 to 4, this bearing device has a sensor unit 20 and a claw pole type generator 30 attached to one axial end of a self-aligning bearing 10.

[0017] The self-aligning bearing 10 is a self-aligning roller bearing having an outer ring 11 having a spherical raceway 11a on its inner circumference, an inner ring 12 having double row raceway grooves 12a on its outer circumference, and spherical rollers 13 as double row rolling elements arranged so as to be able to roll freely between the spherical raceway 11a of the outer ring 11 and each raceway groove 12a of the inner ring 12, with the outer ring 11 being a fixed ring fixed to a housing or the like (not shown), and the inner ring 12 being a rotating ring attached to a rotating shaft (not shown) so as to rotate integrally with it.

[0018] The outer ring 11 has a shoulder 11b formed only on one end side (the left side in FIG. 1), and an extension 11c that protrudes annularly from the outer periphery of the shoulder 11b axially outward. The inner ring 12 has shoulders 12b, 12c on both axial sides, and the outer diameter of the shoulder 12b on one end side is smaller than the outer diameter of the shoulder 12c on the other end side. The inner ring 12 has an extension 12d that protrudes annularly from the inner periphery of the shoulder 12b on the one end side axially outward. The sensor unit 20 and the generator 30 are arranged in the radial gap between the extension 11c of the outer ring 11 and the extension 12d of the inner ring 12.

[0019] The sensor unit 20 has a holder 21 that constitutes a part of the generator 30 as described below, and a substrate 22 that is attached to the holder 21.

[0020] The holder 21 is formed by pressing a single metal plate, and a part of it becomes part of the stator 32 of the generator 30, so that a magnetic metal plate such as a steel plate is used as the material of the holder 21.

[0021] The holder 21 has an annular disk portion 21a expanding in the radial and circumferential directions, a fitting portion 21b protruding annularly from the outer periphery of the disk portion 21a in the axial direction outward, and claw-shaped claw poles 35a extending axially outward at regular intervals from the inner periphery of the disk portion 21a in the circumferential direction and forming part of the stator 32 of the generator 30. The fitting portion 21b is press-fitted into the inner periphery of the extension portion 11c of the outer ring 11 of the self-aligning bearing 10, thereby being fixed to the outer ring 11.

[0022] The substrate 22 is made of a printed wiring board in the shape of an arc plate, and is attached by a plurality of screws (not shown) to the axially outer surface of the disk portion 21a of the holder 21. The substrate 22 can also be adhered to the disk portion 21a of the holder 21 by an adhesive or an adhesive sheet.

[0023] An acceleration sensor 23, a wireless communication module 24, and a power supply circuit 25 are mounted on the surface of the substrate 22 opposite to the surface attached to the holder 21, and a power supply input terminal 26 is provided at one end in the circumferential direction.

[0024] The wireless communication module 24 includes a communication circuit that converts the detection result of the acceleration sensor 23 and the like into radio waves and radiates them from an antenna. Note that the antenna is arranged so as not to come into contact with other members such as a sealing material in order to avoid a deterioration in wireless communication performance.

[0025] The power supply circuit 25 is a circuit that converts AC power generated by the generator 30 into DC power used by the acceleration sensor 23 and the wireless communication module 24 .

[0026] The generator 30 comprises a magnetic ring 31 arranged so as to be rotatable integrally with the inner ring 12 of the self-aligning bearing 10, and an annular stator 32 fixed to the outer ring 11 in a state facing the magnetic ring 31 across an air gap in the radial direction. Here, the "radial direction" refers to the radial direction that forms the spherical orbit of the outer ring.

[0027] The magnetic ring 31 is a rotor that generates a rotating magnetic field for the stator 32, and is fixed to the inner ring 12 by being pressed or glued onto the outer periphery of the extension portion 12d of the inner ring 12 so that it does not protrude radially outward from the shoulder portion 12c on one end side of the inner ring 12.

[0028] This magnetic ring 31 has magnets 31a made of magnetic rubber, magnetized with alternating north and south poles in the circumferential direction, bonded to a core metal 31b over its entire circumference (see FIG. 5). The bonding method may be vulcanization bonding.

[0029] The stator 32 is a stator that guides the magnetic flux emitted from the magnetic ring 31 with a yoke structure and induces an AC voltage in a coil 34 wound around a bobbin 33 in the yoke structure. The yoke structure is composed of a main stator 35 formed from the inner periphery of the holder 21 of the sensor unit 20, and a sub-stator 36 combined with the main stator 35. The main stator 35 (including the holder 21 of the sensor unit 20) is formed from a magnetic metal plate such as a steel plate as described above, and the sub-stator 36 is also formed by pressing from the same magnetic metal plate as the main stator 35 so as to function as a yoke.

[0030] 4 and 5, the sub-stator 36 has an annular disk portion 36a expanding in the radial and circumferential directions, an attachment portion 36b projecting annularly from the outer periphery of the disk portion 36a in the axial direction inward, and claw-shaped claw poles 36c extending in the axial direction inward at regular intervals from the inner periphery of the disk portion 36a in the circumferential direction. Although not shown, engagement claws formed at multiple locations in the circumferential direction of the attachment portion 36b are fitted into holes formed in the main stator 35 (disk portion 21a of holder 21), so that the claw poles 36c are fixed to the main stator 35 in a state where they are alternately arranged with the claw poles 35a of the main stator 35 in the circumferential direction. The total number of both claw poles 35a and 36c is equal to the number of poles (total number of N poles and S poles) of the magnet of the magnetic ring 31.

[0031] The claw poles 35a, 36c of the main stator 35 and the sub stator 36 face the magnetic ring 31 radially with an air gap between them, and the opposing surfaces of the claw poles 35a, 36c and the magnetic ring 31 are each formed as a sphere centered on the alignment center of the self-aligning bearing 10 (see Figure 1).

[0032] The bobbin 33, with the coil 34 wound around it, is disposed in the space inside the main stator 35 and the sub stator 36. The inner peripheral surface of the bobbin 33 is formed into a spherical surface that conforms to the opposing surfaces of the claw poles 35a, 36c facing the magnetic ring 31 (see FIG. 1).

[0033] Both ends of the coil 34 , the start and end of which are wound, are passed through wiring holes (not shown) formed in the mounting portion 36 b of the sub-stator 36 and connected to input terminals of the power supply circuit 25 of the sensor unit 20 .

[0034] In the generator 30 configured as described above, the magnetic flux coming out of the N pole of the magnet of the magnetic ring 31 enters the claw pole 35a of the main stator 35 or the claw pole 36c of the sub stator 36, passes through the mounting portion 36b of the sub stator 36, goes around the coil 34, reaches the claw pole 36c of the sub stator 36 or the claw pole 35a of the main stator 35, and returns to the S pole of the magnet. Also, when the positions of the N pole and S pole of the magnet are interchanged with the rotation of the inner ring 12, the direction of the magnetic flux is reversed. The alternating magnetic field generated in this way generates an AC voltage at both ends of the coil 34, and the generated AC power is supplied to the power supply circuit 25 of the sensor unit 20.

[0035] The acceleration sensor 23 and wireless communication module 24 connected to the output terminal of the power supply circuit 25 are operated by power sent from the power supply circuit 25, and transmit detection data of the acceleration sensor 23 to the outside via wireless communication.

[0036] The bearing device of this embodiment has the above-mentioned configuration, and the opposing surfaces of the claw poles 35a, 36c of the stator 32 and the magnetic ring 31 that constitute the claw pole type generator 30 attached to the self-aligning bearing 10 are each formed as a spherical surface centered on the alignment center of the self-aligning bearing 10, so that even if the inner ring 12 is tilted (aligned) with respect to the outer ring 11 of the self-aligning bearing 10, the distance between the claw poles 35a, 36c of the stator 32 and the magnetic ring 31 remains constant. Therefore, the generator 10 can supply sufficient power to the sensor unit 20 without the risk of contact between the stator 32 and the magnetic ring 31 and without a decrease in power generation efficiency.

[0037] Here, the "alignment center" refers to the center of the spherical surface of the inner circumference of the outer ring. To find this "alignment center," for example, a three-dimensional measuring machine is used. For convenience of explanation, the outer ring is assumed to have a cylindrical outer circumference, and the line forming the center of this cylindrical shape is called the "axis of the outer ring." First, in a measurement section including the axis of the outer ring, three or more points on the spherical surface of the inner circumference of the outer ring are measured to find the spherical center of the inner circumference of the outer ring on the measurement section. Similarly, the center of the inner circumference of the stator is measured at three or more points on the inner circumference of the stator on the same measurement section including the axis of the outer ring, and the spherical center of the inner circumference of the stator is found. Similarly, the spherical center of the spherical magnetic ring is measured at three or more points on the outer circumference of the spherical magnetic ring on the same measurement section including the axis of the outer ring, and the spherical center of the outer circumference of the spherical magnetic ring is found. Although the outer ring, stator, and spherical magnetic ring each include manufacturing errors, theoretically these three spherical centers are the same.

[0038] In addition, in the generator 30, the inner circumferential surface of the bobbin 33 is formed into a spherical surface that conforms to the opposing surfaces of the claw poles 35a, 36c of the stator 32 facing the magnetic ring 31. Therefore, compared to a bobbin whose inner circumferential surface is formed into a cylindrical surface, the space in which the coil 34 can be wound is larger, and the number of turns of the coil 34 is accordingly greater, resulting in higher power generation performance.

[0039] Furthermore, the outer diameter of shoulder 12b at one end of inner ring 12 of self-aligning bearing 10 is formed smaller than the outer diameter of shoulder 12c at the other end, and magnetic ring 31 is attached to the outer periphery of extension 12d protruding from shoulder 12c at one end so that it does not protrude radially outward from shoulder 12c. This has the advantage that the radial dimensions of sensor unit 20 can be made large, and the acceleration sensor 23, wireless communication module 24, and power supply circuit 25 can be easily implemented on substrate 22 built into sensor unit 20.

[0040] Figure 6 shows a modification of the position of the generator 30 in the bearing device of the above-mentioned embodiment. In this modification, the outer diameters of the shoulders 12b, 12c on both axial sides of the inner ring 12 are made the same. As a result, the position of the generator 30 has moved radially outward compared to the examples shown in Figures 1 to 5, and the radial dimension of the sensor unit 20 has become smaller by that amount, but the strength of the inner ring 12 can be ensured to be equivalent to that of a typical self-aligning roller bearing.

[0041] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0042] For example, the self-aligning bearing may be a self-aligning roller bearing in which the outer ring is a fixed ring and the inner ring is a rotating ring as in the embodiment, or it may be a self-aligning roller bearing in which the outer ring is a rotating ring and the inner ring is a fixed ring, or a self-aligning ball bearing in which one of the outer and inner rings is a fixed ring and the other is a rotating ring.

[0043] Furthermore, the present invention is not limited to a bearing device equipped with a claw-pole type generator as in the embodiment, but can be effectively applied to a bearing device equipped with a generator of a type in which a stator fixed to the fixed ring of a self-aligning bearing and a magnetic ring fixed to the rotating ring face each other with an air gap between them. [Explanation of symbols]

[0044] 10 Self-aligning bearings (self-aligning roller bearings) 11 Outer ring (fixed ring) 11a Spherical orbit 11b Shoulder 11c extension 12 Inner wheel (rotating wheel) 12a Raceway groove 12b, 12c Shoulder 12d extension 13 Spherical roller (rolling element) 20 Sensor unit 21 Holder 22 Substrate 30 Generator 31 Magnetic Ring 32 Stator 33 Bobbin 34 Coil 35 Main stator 35a Claw Pole 36 Substater 36c Claw Pole

Claims

1. a self-aligning bearing (10) having an outer ring (11) having a spherical raceway (11a) on its inner circumference, an inner ring (12) having double row raceway grooves (12a) on its outer circumference, and double row rolling elements (13) rollably disposed between the spherical raceway (11a) of the outer ring (11) and each raceway groove (12a) of the inner ring (12); a sensor unit (20) fixed to a fixed race of the outer race (11) and the inner race (12); A generator (30) that supplies power to the sensor unit (20), The generator (30) is a bearing device including a magnetic ring (31) arranged to be rotatable integrally with one of the rotating races of the outer ring (11) and the inner ring (12), and an annular stator (32) fixed to the fixed race and facing the magnetic ring (31) with an air gap in the radial direction, A bearing device characterized in that the opposing surfaces of the stator (32) and the magnetic ring (31) are each formed into a spherical surface centered on the alignment center of the self-aligning bearing (10).

2. 2. The bearing device according to claim 1, wherein the stator (32) of the generator (30) incorporates a bobbin (33) around which a coil (34) is wound, and the inner peripheral surface of the bobbin (33) is formed into a spherical surface that conforms to the opposing surface of the stator (32) facing the magnetic ring (31).

3. 3. A bearing device as described in claim 1 or 2, wherein the inner ring (12) is a rotating raceway ring, the outer diameter of one of the shoulder portions (12b, 12c) on both axial sides of the inner ring (12) is smaller than the outer diameter of the other shoulder portion (12c), and the magnetic ring (31) is attached to the outer periphery of an extension portion (12d) that protrudes annularly axially outward from the inner periphery of the one shoulder portion (12b).

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