Bearing device

Abstract

To provide a bearing device that can improve sealing performance. [Solution] The bearing device 1 of this disclosure comprises a bearing 2 including an outer ring 3, an inner ring 4, and rolling elements 8, a magnetic ring 7 fixed to the inner ring 4 which is a rotating ring, and a sensor unit 6 fixed to the outer ring 3 which is a stationary ring. The sensor unit 6 faces the magnetic ring 7 radially RD via a first gap d1 and includes a stator 5 which together with the magnetic ring 7 constitutes a generator G. A wall portion 61 is provided on either the magnetic ring 7 or the inner ring 3, and the wall portion 61 faces the first gap d1 in the axial direction AD. The wall surface 62 of the wall portion 61 facing the axial direction AD and the stator end surface 64 of the stator 5 facing the axial direction AD face each other in the axial direction AD via a second gap d2. A labyrinth seal LS is formed between the first gap d1 and the second gap d2.

Description

[Technical Field]

[0001] The present invention relates to a bearing device comprising a magnetic ring fixed to a rotating ring of a bearing and a sensor unit fixed to a stationary ring of the bearing. [Background Art]

[0002] A bearing device equipped with a generator that transmits detection signals from a sensor mounted on the bearing using the generated electric power has been proposed (for example, Patent Document 1). The detection signal from the sensor is transmitted wirelessly, for example. In the bearing device of Patent Document 1, a magnetic ring, a stator, a sensor, and a circuit board are arranged on one axial end side of an annular space formed by an outer ring and an inner ring. For example, a wireless communication circuit and a power source are mounted on the circuit board. In Patent Document 1, these components are arranged so as not to overlap in the axial direction of the bearing. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent No. 7450657 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] In the structure as disclosed in Patent Document 1, a minute axially extending gap (annular gap) is formed between the magnetic ring and the stator, constituting a labyrinth seal. However, since the gap is structured to extend only in the axial direction, the sealing performance is not high.

[0005] An object of the present invention is to provide a bearing device capable of achieving improved sealing performance. [Means for Solving the Problems]

[0006] The bearing device of the present invention comprises a bearing including an outer ring, an inner ring, and rolling elements; a magnetic ring fixed to the rotating ring of the outer ring and the inner ring; and a sensor unit fixed to the stationary ring of the outer ring and the inner ring. The sensor unit includes a stator that faces the magnetic ring in a first direction via a first gap and, together with the magnetic ring, constitutes a generator. One of the magnetic ring and the rotating ring is provided with a wall portion having a wall surface extending in the first direction or in a second direction intersecting the first direction. The stator has a stator surface facing the first direction or in a third direction intersecting the second direction via a second gap with respect to the wall surface. A labyrinth seal is formed between the first gap and the second gap.

[0007] In the present invention, the first gap and the second gap may be in communication with each other. Also, if the wall surface extends in the first direction, the first direction may be the radial direction of the bearing, and the third direction may be the axial direction of the bearing.

[0008] In this configuration, the first gap extends in a direction perpendicular to the first direction, and the second gap extends in a direction perpendicular to a third direction that intersects the first direction. These first and second gaps constitute a labyrinth seal. In other words, the gaps of the labyrinth seal include at least two directions. By making the paths of the labyrinth seal gaps complex in this way, the intrusion of foreign matter into the bearing is suppressed, and the sealing performance is improved.

[0009] In the present invention, the wall portion may be a projection formed at one end of the magnetic ring in an orthogonal direction perpendicular to the first direction, projecting in either the first or second direction. With this configuration, the seal structure of the present disclosure can be realized without changing the structure of the bearing. As a result, the seal structure of the present disclosure can also be applied to existing bearing devices.

[0010] In the present invention, the wall portion may be a notched step portion provided at one axial end of the rotating ring. This configuration makes it possible to miniaturize the magnetic ring and simplify its structure. [Effects of the Invention]

[0011] According to the bearing device of the present invention, by making the path of the labyrinth seal gap complex, the intrusion of foreign matter into the bearing is suppressed, and the sealing performance is improved. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view of a bearing device according to the first embodiment of the present invention. [Figure 2] This is a cross-sectional view showing the sensor unit and magnetic ring of the bearing device. [Figure 3] This is a disassembled perspective view of the sensor unit. [Figure 4] This is a cross-sectional view of a bearing device according to a second embodiment of the present invention. [Figure 5] This is a cross-sectional view showing the sensor unit and magnetic ring of the bearing device. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described below with reference to the drawings. In the following description, "axial direction," "radial direction," and "circumferential direction" refer to the "axial direction," "radial direction," and "circumferential direction" of the bearing, respectively. In the axial direction, the side toward the center of the rolling element is referred to as the "inside," and the opposite side is referred to as the "outside."

[0014] [First Embodiment] A bearing device 1 according to the first embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a cross-sectional view of the bearing device 1 of this embodiment. The bearing device 1 of this embodiment is applied, for example, to a motor of industrial machinery. However, the application of the bearing device 1 is not limited to this.

[0015] The bearing device 1 comprises a bearing 2, a sensor unit 6, and a magnetic ring 7. The bearing 2 includes an outer ring 3 and an inner ring 4. In this embodiment, the bearing 2 is an inner ring rotating type bearing, where the outer ring 3 is a fixed ring and the inner ring 4 is a rotating ring. Furthermore, although the bearing 2 in this embodiment is a deep groove ball bearing, the bearing 2 is not limited to a deep groove ball bearing and may be an angular contact ball bearing, a tapered roller bearing, a sliding bearing, etc.

[0016] The bearing 2 includes an outer ring 3, an inner ring 4, rolling elements 8, a cage 9, and a seal 10. An outer ring raceway surface 3a is formed on the inner circumferential surface 3c of the outer ring 3, and an inner ring raceway surface 4a is formed on the outer circumferential surface 4c of the inner ring 4. Multiple rolling elements 8 are interposed on these outer ring raceway surfaces 3a and inner ring raceway surfaces 4a. The rolling elements 8 are, for example, balls. The rolling elements 8 are held at equal intervals in the circumferential direction by the cage 9. The cage 9 in this embodiment is a so-called crown-shaped cage made of resin. However, the shape and material of the cage 9 are not limited to this.

[0017] A first notch 3b is formed on the inner circumferential surface of one end of the outer ring 3's axial AD (right end in Figure 1). The first notch 3b is formed by the inner circumferential surface 3c of the outer ring 3 being recessed outward in the radial direction RD. A second notch 4b is formed on the outer circumferential surface 4c of the inner ring 4's axial AD (right end in Figure 1). The second notch 4b is formed by the outer circumferential surface 4c of the inner ring 4 being recessed inward in the radial direction RD.

[0018] A seal mounting groove 3d is formed on the inner circumferential surface of the other end (left end in Figure 1) of the outer ring 3 in the axial direction AD. The seal mounting groove 3d is an annular groove formed on the inner circumferential surface 3c of the outer ring 3. The base end 10a of the seal 10 is fitted into the seal mounting groove 3d. A seal sliding groove 4f is formed on the outer circumferential surface of the other end (left end in Figure 1) of the inner ring 4 in the axial direction AD. The seal sliding groove 4f is an annular groove formed on the outer circumferential surface 4c of the inner ring 4. The lip portion 10b at the tip of the seal 10 slides in the seal sliding groove 4f.

[0019] The magnetic ring 7 includes an annular core bar 7a and a multipolar magnet 7b provided on the outer peripheral surface of the core bar 7a. The magnetic ring 7 is a magnetic member obtained by alternately magnetizing N poles and S poles in the circumferential direction. Specifically, the multipolar magnet 7b is formed, for example, by vulcanizing and adhering a magnetic material obtained by kneading magnetic powder and rubber to the core bar 7a, and then alternately magnetizing N poles and S poles in the circumferential direction of the magnetic material. A flange portion 7c extending radially inward is formed at one axial end portion (the right end portion in Fig. 2) of the core bar 7a. The rigidity of the core bar 7a is increased by the flange portion 7c.

[0020] The magnetic ring 7 is fixed to the inner ring 4. In the present embodiment, the inner peripheral surface of the core bar 7a is press-fitted onto the outer peripheral surface 4c of the inner ring 4. The flange portion 7c is accommodated in the second notch portion 4b of the inner ring 4. The magnetic ring 7 is arranged so as not to protrude outward in the axial direction AD from the end surface 20 of the inner ring 4.

[0021] The sensor unit 6 includes a stator 5, a holding member 12, a circuit board 13, and a cover 14. The stator 5 is fixed to the outer ring 3. A generator G is configured by the stator 5 and the magnetic ring 7. The generator G of the present embodiment is a claw-pole generator, but may be a generator of another structure. Details of the structure of the stator 5 will be described later.

[0022] The holding member 12 of the sensor unit 6 is made of an annular magnetic material. That is, the holding member 12 functions as a magnetic member 27 of the stator 5 described later. Specifically, the holding member 12 has an outer peripheral portion 27a and an inner peripheral portion 27b each extending in the axial direction AD, and a bottom portion 27c that connects the outer peripheral portion 27a and the inner peripheral portion 27b and extends in the radial direction RD, and has a U-shaped cross-section that opens outward in the axial direction AD.

[0023] In the present embodiment, as shown in Fig. 3, the inner peripheral portion 27b is formed by a plurality of claw portions 27d spaced apart in the circumferential direction. Further, a plurality of recesses 27e spaced apart in the circumferential direction are formed in the bottom portion 27c. The recess 27e of the present embodiment is a through hole penetrating the bottom portion 27c in the axial direction AD.

[0024] The outer diameter surface of the outer circumference 27a of the retaining member 12 shown in Figure 2 is fitted into the inner diameter surface of the first notch 3b of the outer ring 3 shown in Figure 1. This fixes the retaining member 12 to the outer ring 3. However, the retaining member 12 may be fixed to the outer ring 3 by a combination of press-fitting and adhesive, or by other methods. The retaining member 12 is press-fitted or adhesively bonded so as not to protrude from the end face 11 in the axial direction AD of the outer ring 3.

[0025] When the retaining member 12 is fixed to the first notch 3b, a certain gap in the axial direction AD is secured between the rolling element 8 and the retaining member 12. As a result, even if axial displacement AD occurs between the rolling element 8 and the retaining member 12, contact between the rolling element 8 and the retaining member 12 can be avoided by this gap.

[0026] The circuit board 13 is supported on the bottom 27c of the retaining member 12. More specifically, as shown in Figure 2, the circuit board 13 is fixed to the surface of the bottom 27c of the retaining member 12 that faces outward in the axial direction AD. In this embodiment, the circuit board 13 is fixed to the retaining member 12 by a plurality of screws (not shown). However, the means of fixing the circuit board 13 is not limited to this, and for example, it may be fixed to the retaining member 12 by adhesive.

[0027] The circuit board 13 is positioned in the region outside the radial RD of the retaining member 12. More specifically, the circuit board 13 is positioned in the region outside the radial RD of the retaining member 12 beyond the recess 27e.

[0028] The outer side of the circuit board 13 in the axial direction A and D is covered by a cover 14. The cover 14 is a non-metallic resin component and protects the circuit board 13 inside the sensor unit 6. Instead of the cover 14, the circuit board 13 may be sealed using a resin encapsulant.

[0029] One or more bearing monitoring sensors 15 are mounted on the circuit board 13 to monitor the state of the bearing 2. The bearing monitoring sensors 15 are, for example, acceleration sensors, temperature sensors, etc. The number and types of bearing monitoring sensors can be set arbitrarily.

[0030] The circuit board 13 also has a power supply circuit 17 and a wireless communication circuit 18 mounted on it. The power supply circuit rectifies the AC power generated by the generator G and converts it into DC power. The DC power converted by the power supply circuit 17 operates the bearing monitoring sensor 15 and the wireless communication circuit 18.

[0031] The wireless communication circuit 18 transmits the output of the bearing monitoring sensor 15 to the outside wirelessly. The circuit board 13 on which the wireless communication circuit 18 is mounted is positioned opposite the resin cover 14 in the axial direction A / D. As a result, the wireless communication circuit 18 is not sealed with a conductive material such as metal, thus enabling wireless communication. However, instead of the wireless communication circuit 18, a wired output circuit may be mounted to transmit the output of the bearing monitoring sensor 15 to the outside via a wire.

[0032] The stator 5 is positioned in the retaining member 12. The stator 5 is positioned in the region of the retaining member 12 that is inside the radial direction RD. More specifically, the stator 5 is positioned in the region of the retaining member 12 that is inside the radial direction RD beyond the recess 27e. The stator 5 faces the first direction, the radial direction RD, via the magnetic ring 7 and a first gap d1.

[0033] The stator 5 includes two magnetic members 27 and 28, a bobbin 23, and a coil 24. The portion of the holding member 12 that is radially RD inward of the recess 27e constitutes one of the magnetic members 27 of the stator 5. More specifically, the portion of the bottom 27c of the holding member 12 that is radially RD inward of the recess 27e and the inner circumference 27b of the holding member 12 constitute one of the magnetic members 27 of the stator 5. In this way, the holding member 12 also serves as the magnetic member 27 of the stator 5, thus reducing the number of parts. The magnetic member 27 (inner circumference 27b) of the stator 5 faces the multipole magnet 7b of the magnetic ring 7 in the radial direction RD (first direction) via a first gap d1.

[0034] As shown in Figure 3, the other magnetic member 28 of the stator 5 is an annular member with a U-shaped cross-section, having an outer circumferential portion 28a and an inner circumferential portion 28b extending in the axial direction AD, and a bottom portion 28c extending in the radial direction RD that connects the outer circumferential portion 28a and the inner circumferential portion 28b. The magnetic member 28 in this embodiment has a U-shape that opens inward in the axial direction AD. Since the magnetic member 28 has a U-shaped cross-section and a simple shape, press working is easy, and manufacturing costs can be reduced.

[0035] The inner circumference 28b of the magnetic member 28 has a plurality of claw portions 28d spaced apart in the circumferential direction. These claw portions 28d of the inner circumference 28b of the magnetic member 28 are arranged alternately in the circumferential direction with the plurality of claw portions 27d of the inner circumference 27b of the magnetic member 27.

[0036] The claw-pole type generator G described above is formed by multiple claw portions 27d of one magnetic member 27 and multiple claw portions 28d of the other magnetic member 28 in the stator 5, along with the magnetic ring 7. The total number of claw portions 27d and 28d is equal to the number of poles of the multipole magnet 7b (the total number of north and south poles).

[0037] Multiple convex portions 28e are formed on the inner end of the outer circumference 28a of the stator 5 in the axial direction AD, spaced apart in the circumferential direction. These convex portions 28e of the magnetic member 28 are fitted into recesses 27e of the magnetic member 27. The fitting of the multiple recesses 27e and the multiple convex portions 28e causes the multiple claw portions 27d of the magnetic member 27 and the multiple claw portions 28d of the magnetic member 28 to be arranged alternately with gaps in the circumferential direction. The inner end faces of the magnetic member 28 in the axial direction AD, excluding the convex portions 28e, abut against the bottom portion 27c of the magnetic member 27 (holding member 12).

[0038] In this way, by assembling the components by fitting together the multiple recesses 27e and the multiple protrusions 28e, the two magnetic members 27 and 28 can be aligned coaxially without the use of a jig, and the multiple claw portions 27d and 28d can be easily aligned.

[0039] However, the connection between the recess 27e of the magnetic member 27 and the protrusion 28e of the magnetic member 28 is not limited to press-fitting, and may be connected by, for example, adhesive bonding or welding using a laser, or a combination of press-fitting, adhesive bonding, and welding. Preferably, three or more recesses 27e and three or more protrusions 28e are formed.

[0040] Furthermore, the recessed portion 27e and the convex portion 28e may be omitted. In this case, for example, with the coaxial arrangement of the magnetic members 27 and 28 and the positioning of the multiple claw portions 27d and 28d performed using a jig (not shown), the contact surfaces between the bottom portion 27c of the magnetic member 27 and the end of the outer peripheral portion 28a of the magnetic member 28 may be fixed by laser welding or the like.

[0041] A coil 24, formed by winding magnet wire multiple times, is positioned in grooves provided circumferentially on the bobbin 23. The bobbin 23 with the coil 24 wound on it is housed inside the U-shaped cross-section magnetic member 28 of the stator 5. Note that the bobbin 23 may be omitted.

[0042] The magnetic flux emanating from the north pole of the multipole magnet 7b in Figure 2 enters the magnetic material member 27 (or magnetic material member 28) through, for example, the multiple claw portions 27d (or multiple claw portions 28d) which are the magnetic poles, circulates around the coil 24, passes through the adjacent multiple claw portions 28d (or multiple claw portions 27d) and returns to the south pole of the multipole magnet 7b. When the positions of the north and south poles of the multipole magnet 7b are swapped by the rotation of the inner ring 4, the direction of the magnetic flux is reversed. The alternating magnetic field generated in this way generates alternating current power at both ends of the coil 24.

[0043] The ends of the coil 24 drawn from the stator 5 are connected to terminals (not shown) provided on the circuit board 13. The AC power output from the generator G due to the rotation of the inner ring 4 is converted to DC power by the power supply circuit 17 on the circuit board 13. As described above, this DC power is used by the wireless communication circuit 18 to wirelessly transmit the output of the bearing monitoring sensor 15 to the outside.

[0044] [Seal structure] As described above, the stator 5 of the generator G faces the multipole magnets 7b of the magnetic ring 7 in the radial direction RD (first direction D1) via a first gap d1. In other words, a first gap d1 is formed between the stator 5 and the magnetic ring 7 in the radial direction RD. The first gap d1 is an annular gap and extends in the axial direction AD in the cross-sectional view of Figure 2. The radial dimension of the first gap d1 (dimension in the first direction D1) is, for example, 0.3 mm to 0.6 mm. However, the dimension of the first gap d1 is not limited to this.

[0045] The multipole magnet 7b has an opposing portion 60 and a projection 61. The opposing portion 60 faces the inner circumference 27b of the stator 5 in the radial direction RD with a first gap d1. The projection 61 is provided at the axially inward end 7d of the opposing portion 60 and protrudes in the radial direction RD (first direction D1). In detail, with respect to the axial direction AD, the projection 61 is provided at the end 7d of the opposing portion 60 that is axially inward from the bottom 27c of the stator 5. In other words, the multipole magnet 7b of the magnetic ring 7 extends axially inward (towards the rolling element 8) from the bottom 27c of the stator 5 with respect to the axial direction AD, and the projection 61 is provided at its end 7d.

[0046] With respect to the axial direction AD, the projection 61 is set to be at a certain distance from the rolling element 8 so as not to come into contact with it. The projection 61 may be magnetized or unmagnetized, similar to the opposing portion 60. In this embodiment, the projection 61 extends in the radial direction RD (first direction D1), but as shown by the dashed line in Figure 2, it may also extend in a second direction D2 that intersects the radial direction RD (first direction D1).

[0047] The height of the projection 61 in the radial direction RD (first direction D1) is set to be approximately the same as the radial dimension of the first gap d1, or greater than or equal to the radial dimension of the first gap d1. The projection 61 has a wall surface 62 that extends in the radial direction RD (first direction D1) and faces outward in the axial direction AD. In other words, in this embodiment, the projection 61 constitutes a wall portion 61 having a wall surface 62 that extends in the first direction D1 or the second direction D2. In this embodiment, the wall portion 61 is formed at one end 7d of the magnetic ring 7 in an orthogonal direction (axial direction AD) perpendicular to the first direction D1 (radial direction RD), and protrudes in the first direction D1 (radial direction RD).

[0048] The wall surface 62 of the projection 61 faces the stator surface 64, which faces inward in the axial direction AD at the bottom 27c of the stator 5, in the axial direction AD (third direction D3). However, the wall surface 62 may also extend in a second direction D2 that intersects the radial direction RD (first direction D1), as shown by the dashed line in Figure 2.

[0049] The stator surface 64 faces the axial direction AD (third direction D3) through a second gap d2 with the wall surface 62 of the projection 61. In this embodiment, the axial direction AD constitutes a third direction D3 that intersects both the first direction D1 and the second direction D2.

[0050] A second gap d2 is formed between the stator surface 64 of the stator 5 and the wall surface 62 of the projection 61 of the magnetic ring 7 in the radial direction RD. In the cross-sectional view of Figure 2, the second gap d2 extends in the radial direction RD. The axial dimension of the second gap d2 (dimension in the third direction D3) is set to, for example, about 0.2 mm to 0.8 mm.

[0051] In this embodiment, the wall surface 62 and the stator surface 64 extend in the radial direction RD, and both surfaces 62 and 64 face each other in the axial direction AD. That is, the radial direction RD corresponds to the first direction D1, and the axial direction AD corresponds to the third direction D3.

[0052] Furthermore, in the cross-sectional view of Figure 2, the first gap d1 extends in the axial direction AD, the second gap d2 extends in the radial direction, and the first gap d1 and the second gap d2 are in communication with each other. In other words, the direction of extension of the first gap d1 and the direction of extension of the second gap d2 have a certain angle (90° in this embodiment), and the first gap d1 and the second gap d2 are in communication with each other in the circumferential direction. As a result, a labyrinth seal LS is formed between the first gap d1 and the second gap d2.

[0053] According to the above configuration, the first gap d1 extends in the axial direction AD, and the second gap d2 extends in the radial direction RD perpendicular to the axial direction AD, and these first gap d1 and second gap d2 constitute a labyrinth seal LS. In other words, the gap of the labyrinth seal LS includes at least two directions. By making the path of the gap of the labyrinth seal LS complex in this way, the intrusion of foreign matter into the bearing is suppressed, and the sealing performance is improved.

[0054] Furthermore, the wall portion 61 having a wall surface 62 is formed on one end 7d of the axial AD of the magnetic ring 7 and is a projection 61 that protrudes radially RD. In other words, since the projection 61 having a wall surface 62 is formed on the axially inward side, even if the path of the labyrinth seal LS is made complex, the magnetic ring 7 and the sensor unit 6 do not protrude axially outward from the end faces 20 and 11 of the inner ring 4 and outer ring 3, respectively. This makes it possible to improve sealing performance while maintaining the external dimensions.

[0055] [Second Embodiment] Next, the bearing device 1A of the second embodiment will be described with reference to Figures 4 and 5. In the following description of the second embodiment, components identical to those of the first embodiment will be denoted by the same reference numerals, and detailed descriptions will be omitted.

[0056] In the second embodiment, the wall portion 61 having a wall surface 62 is formed by a stepped portion 4d of a second notch portion 4b provided at one end of the axial AD of the inner ring 4 (the right end in Figure 4).

[0057] Similar to the first embodiment, a second notch 4b is formed at one end of the axial AD of the inner ring 4 (the right end in Figure 4), and the magnetic ring 7 is fixed to the inner circumferential surface 4e of this second notch 4b by press-fitting. The outer diameter of the multipole magnet 7b of the magnetic ring 7 is set to be smaller than the outer diameter of the outer circumferential surface 4c of the inner ring 4. Similar to the first embodiment, the inner circumferential portion 27b of the stator 5 faces the multipole magnet 7b in the radial direction RD via a first gap d1.

[0058] The second notch 4b is formed when the outer circumferential surface 4c of the inner ring 4 is recessed inward in the radial direction RD. In other words, the second notch 4b is formed when the diameter of the inner ring 4 is reduced from the outer circumferential surface 4c of the inner ring 4 via the stepped portion 4d. The stepped portion 4d has a wall surface 62 facing outward in the axial direction AD. That is, the end face of the second notch 4b facing outward in the axial direction AD constitutes the wall surface 62 of the stepped portion 4d (wall portion). The wall surface 62 may extend in a second direction D2 that intersects the first direction D1 (radial direction RD), as shown by the dashed line in Figure 5.

[0059] A certain gap 63 is maintained between the magnetic ring 7 and the wall surface 62 of the second notch 4b, preventing a magnetic short circuit between the multipole magnet 7b and the wall (stepped portion 4d). In addition, a portion of the stator surface 64 at the bottom 27c of the stator 5, which faces inward in the axial direction, is connected to the wall surface 62 of the wall (stepped portion 4d) via the second gap d2 and faces in the axial direction AD (third direction D3). Similar to the first embodiment, the first gap d1 and the second gap d2 are set to, for example, about 0.2 mm to 0.8 mm.

[0060] In the cross-sectional view shown in Figure 5, the first gap d1 extends in the axial direction AD, and the second gap d2 extends in the radial direction AD, with the first gap d1 and the second gap d2 communicating with each other. These first gap d1 and second gap d2 constitute the labyrinth seal LS.

[0061] In the second embodiment as well, the path of the labyrinth seal LS becomes more complex due to the first gap d1 extending in the axial direction AD and the second gap d2 extending in the radial direction RD. As a result, the intrusion of foreign matter can be further suppressed and the sealing performance is improved.

[0062] Furthermore, the wall portion is composed of a stepped portion 4d of a second notch 4b provided at one end of the axial AD of the inner ring 2. This makes it possible to improve sealing performance while maintaining external dimensions without adding any new parts. As a result, the bearing device 1, in particular the magnetic ring 7, can be miniaturized and its structure simplified.

[0063] The present invention is not limited to the embodiments described above, and various additions, modifications, or deletions are possible without departing from the spirit of the invention. For example, although the above embodiments described an inner-ring rotating type bearing 2, the present invention can also be applied to an outer-ring rotating type bearing. Therefore, such bearings are also included within the scope of the present invention. [Explanation of symbols]

[0064] 1,1A Bearing device, 2 Bearing, 3 Outer ring (fixed ring), 4 Inner ring (rotating ring), 4b Second notch (notch), 4d Step (wall), 5 Stator, 6 Sensor unit, 7 Magnetic ring, 8 Rolling element, 61 Projection (wall), 62 Wall surface, 64 Stator surface, d1 First gap, d2 Second gap, D1 First direction (radial direction), D2 Second direction, D3 Third direction (axial direction), G Generator, LS Labyrinth seal,

Claims

1. A bearing including an outer ring, an inner ring, and rolling elements, A magnetic ring fixed to the rotating ring among the outer ring and the inner ring, A bearing device comprising a sensor unit fixed to the fixed ring among the outer ring and the inner ring, The sensor unit includes a stator that faces the magnetic ring in a first direction via a first gap and, together with the magnetic ring, constitutes a generator. A wall portion is provided on either the magnetic ring or the rotating wheel, having a wall surface extending in the first direction or in a second direction intersecting the first direction. The stator has a stator surface facing a third direction that intersects the first direction or the second direction, with respect to the wall surface and a second gap between them. A bearing device in which a labyrinth seal is formed by the first gap and the second gap.

2. A bearing device according to claim 1, wherein the first gap and the second gap are in communication with each other.

3. In the bearing device according to claim 1, the wall surface extends in the first direction, A bearing device in which the first direction is the radial direction of the bearing and the third direction is the axial direction of the bearing.

4. A bearing device according to any one of claims 1 to 3, wherein the wall portion is a projection formed at one end of the magnetic ring in an orthogonal direction perpendicular to the first direction, and projecting in the first direction or the second direction.

5. A bearing device according to any one of claims 1 to 3, wherein the wall portion is a stepped portion of a notch provided at one axial end of the rotating ring.

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