Bearing device

Abstract

To provide a bearing device for reducing the deformation of both a peripheral face part of a bearing ring of a rolling bearing and a holder of a sensor unit which is pressed thereinto, while fixing both of them.SOLUTION: A rolling bearing 1 has a peripheral face part 12 on one of the inner / outer periphery of a first bearing ring 4. A holder 18 of a sensor unit 2 fixed to the peripheral face part 12 holds a circuit board 17. The holder 18 has a plurality of protrusions 23 provided at peripheral spaces to have a radial interference δr with the peripheral face part 12. The sensor unit 2 is fixed to the first bearing ring 4 only by pressing the plurality of protrusions 23 into the peripheral face part 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bearing device including a rolling bearing and a sensor unit. [Background technology]

[0002] Conventionally, a bearing device has been known in which sensors for detecting the condition of a rolling bearing are mounted on a substrate to form a circuit board, the circuit board is held in a holder and assembled into a sensor unit, and the sensor unit is fixed to a raceway ring.

[0003] When the stator of a generator that supplies power to the circuit board is provided in the sensor unit, the holder may function as a yoke for the stator. Also, when detecting the vibration of a bearing, it may be preferable to arrange the holder coaxially with the raceway to detect the condition of the bearing. In such cases, the holder is made into an annular body and is fixed coaxially to the raceway. The fixing means employed is to fit the holder to one of the inner and outer circumferences of the raceway.

[0004] There are also cases where it is desired to increase the area of ​​the circuit board in order to improve the functionality of the sensor unit, such as by mounting an AC / DC conversion power circuit on the board, mounting a wireless communication circuit on the board, mounting multiple sensors on the board, etc. In such cases, a structure is adopted in which the holder is provided with an annular side portion extending in the radial direction and a fitting portion extending in the axial direction from the raceway side of the annular side portion, the circuit board is attached to the annular side portion, and the fitting portion is press-fitted into the raceway, thereby increasing the area of ​​the circuit board while reducing the axial width of the sensor unit.

[0005] The holder as described above is generally made of metal in order to ensure the strength to withstand press-fitting, and in particular, when the holder is to have a yoke function, it is made of an iron-based magnetic material.

[0006] For example, the sensor-equipped bearing device (bearing device) of Patent Document 1 has a yoke function given to a yoke member (holder), and is configured as a control board (circuit board) with a vibration sensor, temperature sensor, power supply circuit, wireless communication circuit, etc. mounted on a circumferentially long substrate, and the control board is attached to the side of the mounting part (annular side part) of the yoke member facing the rolling element, and the fitting part of the yoke member and the raceway are fitted and fixed with each other's cylindrical surfaces. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2003-307435 A Summary of the Invention [Problem to be solved by the invention]

[0008] When the cylindrical surfaces of the yoke member and the raceway are fitted and fixed to each other as in the sensor-equipped bearing device of Patent Document 1, if an adhesive is used to fix them, a degreasing process is required before bonding, which makes assembly of the bearing device complicated.

[0009] Although it is possible to fix the yoke component and the raceway ring together more easily by pressing them together than by using adhesive, if the radial interference between the raceway ring and the yoke component becomes too large, it becomes difficult to press them together, and the pressure load applied during the press-fitting may cause deformation of the raceway surface and the yoke component, which may adversely affect the performance of the rolling bearing and sensor unit. In particular, when the yoke component is manufactured by pressing or the like, the tolerance width of the yoke component becomes larger compared to when it is machined, which increases the concern that the press-fitting operation will become more difficult.

[0010] In view of the above background, an object of the present invention is to reduce deformation of both the sensor unit and the holder of the sensor unit while fixing the sensor unit by press-fitting the holder into the peripheral surface of the raceway of the rolling bearing. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention adopts Configuration 1, which is a bearing device comprising a rolling bearing having a first raceway, a second raceway, and two or more rolling elements arranged between the first raceway and the second raceway, a sensor unit having a circuit board and a holder for holding the circuit board, wherein the sensor unit is fixed to one of the inner and outer circumferential surface portions of the first raceway, the holder has a plurality of protrusions spaced circumferentially so as to have a radial interference with the one of the circumferential surface portions, and the sensor unit is fixed to the first raceway only by pressing the plurality of protrusions into the one of the circumferential surface portions.

[0012] According to the above configuration 1, when fixing the sensor unit to the first raceway, it is only necessary to press-fit the multiple protrusions of the holder and the peripheral surface portion of the first raceway at multiple points in the circumferential direction. Therefore, the pressing load required for the press-fit is smaller than when the holder and the first raceway are pressed-fitted between their cylindrical surfaces, and thus deformation of the holder and the first raceway due to the press-fit can be reduced.

[0013] In the above configuration 1, configuration 2 can be adopted in which the protrusion is composed of a cantilever beam portion that is disconnected in the circumferential and radial directions from the other portions of the holder other than the protrusion. According to this configuration, the protrusion composed of the cantilever beam portion bends when pressed into the peripheral surface portion of the first raceway ring, and elastically exerts a radial repulsive force, so that the sensor unit can be fixed by pressing in the multiple protrusions and the peripheral surface portion, and even if the tolerance of the radial tightening is large, the deformation of the first raceway ring and the portions of the holder other than the protrusion can be reduced by absorbing it with the bending deformation of the protrusion.

[0014] In the above configuration 1, a configuration 3 can be adopted in which the protrusion is a protruding portion that bulges out from a portion of the holder. According to this configuration 3, even if the tolerance of the radial interference is large, the flattening deformation of the protrusion can absorb the large tolerance, thereby reducing deformation of the first raceway and portions of the holder other than the protrusion.

[0015] In the above configuration 3, a configuration 4 can be adopted in which a notch is formed along the protrusion. According to this configuration 4, at the location where the notch is formed along the protrusion consisting of the overhanging portion, the protrusion is less resisted from deforming in the radial direction, so that the protrusion can be easily deformed in the radial direction when pressed into the peripheral surface portion of the first raceway.

[0016] In any one of the above configurations 1 to 4, a configuration 5 can be adopted in which the holder has an annular side portion extending in the radial direction and a fitting portion protruding in the axial direction from the annular side portion, the fitting portion has the protrusions at multiple locations evenly spaced in the circumferential direction, and the circuit board is attached to the annular side portion in a non-contact state with the multiple protrusions. According to this configuration 5, deformation of the holder and the first race caused by press-fitting the multiple protrusions and the peripheral surface portion of the first race can be made uniform in the circumferential direction, and interference between the deformed protrusions and the circuit board can be avoided, thereby preventing an effect on the performance of the sensor unit and the rolling bearing.

[0017] In any one of the above configurations 1 to 5, a configuration 6 can be adopted in which the protrusion and the peripheral surface portion are in contact only in a region on the reversible moving body side of the axial region where the sensor unit and the first raceway face each other in the radial direction. According to this configuration 6, the contact between the protrusion and the peripheral surface portion can be reduced compared to a case where the protrusion is in contact with the peripheral surface portion over the entire axial region, so that the pressing load required for press-fitting can be further reduced, and contact between the sensor unit and the first raceway can be avoided until the protrusion comes into contact with the peripheral surface portion during the press-fitting process, so that the sensor unit can be prevented from being press-fitted at an angle relative to the peripheral surface portion.

[0018] In the above configuration 6, a configuration 7 can be adopted in which the protrusion is in contact with the peripheral surface portion with a width in the axial direction. According to this configuration 7, even if the arrangement of the protrusion is limited to the reverse moving body side of the axial region, the attitude of the sensor unit with respect to the first race can be easily stabilized.

[0019] In any one of the above configurations 1 to 7, a configuration 8 can be adopted in which a portion of the sensor unit that is closer to the rolling element in the axial direction than the protrusion is clearance-fitted with the first raceway ring. According to this configuration 8, by providing a clearance-fit portion between the sensor unit and the first raceway ring, radial contact between the sensor unit and the first raceway ring can be reliably reduced at a stage before the protrusion of the sensor unit reaches the peripheral surface during the press-fitting process, and the pressing load required for press-fitting can be suppressed. Effect of the Invention

[0020] As described above, by employing the above configuration 1, the present invention can reduce deformation of the peripheral surface of the raceway of the rolling bearing and the holder of the sensor unit while fixing them together by press-fitting the two together. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a vertical sectional side view showing a bearing device according to a first embodiment of the present invention; [Diagram 2] FIG. 2 is a longitudinal sectional front view showing the bearing device of FIG. [Diagram 3] FIG. 2 is a perspective view showing the bearing device of FIG. [Figure 4] Enlarged view of the sensor unit in Figure 2 [Diagram 5] FIG. 2 is an exploded perspective view of the sensor unit of FIG. 1; [Figure 6] FIG. 2 is a perspective view showing the sensor unit of FIG. 1 with the cover removed; [Figure 7] FIG. 2 is a perspective view showing a state in which the sensor unit in FIG. 1 is separated from a rolling bearing; [Figure 8] FIG. 11 is a perspective view showing a main part of a bearing device according to a second embodiment of the present invention; [Figure 9] FIG. 9 is a longitudinal sectional front view showing the sensor unit of FIG. 8 . [Figure 10] FIG. 11 is a longitudinal sectional front view showing a bearing device according to a third embodiment of the present invention; [Figure 11] FIG. 13 is a perspective view showing a main part of a bearing device according to a fourth embodiment of the present invention; [Figure 12]FIG. 13 is a longitudinal sectional front view showing a sensor unit of a bearing device according to a fourth embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] A bearing device according to a first embodiment (hereinafter simply referred to as "the bearing device") as one example of the present invention will be described with reference to the accompanying drawings, FIGS. 1 to 7. FIG.

[0023] The bearing device shown in FIGS. 1 to 3 includes a rolling bearing 1, a sensor unit 2, and a generator 3. The bearing device shown in FIGS.

[0024] Here, the circumferential direction centered on the central axis of the rolling bearing 1 is referred to as the "circumferential direction", the direction along the central axis of the bearing is referred to as the "axial direction", and the direction perpendicular to the central axis of the bearing is referred to as the "radial direction".

[0025] The rolling bearing 1 has a first raceway 4, a second raceway 5, and two or more rolling elements 6 arranged between the first raceway 4 and the second raceway 5. These rolling elements 6 are held by a cage 7 at equal intervals in the circumferential direction.

[0026] The sensor unit 2 is a unit incorporating an electric circuit that detects at least one of a physical quantity and a chemical quantity related to the state of the rolling bearing 1 and outputs the detection result to a predetermined destination.

[0027] The generator 3 comprises a magnetic ring 8 arranged so as to be rotatable integrally with the second raceway 5, and a stator 9 facing the magnetic ring 8 across a magnetic gap. The relative rotational motion between the first raceway 4 and the second raceway 5 is electromagnetically converted into alternating current by the magnetic ring 8 and the stator 9.

[0028] The rolling bearing 1 is a radial bearing. The rolling bearing 1 is also a standard bearing that complies with a specific standard. Here, a standard bearing refers to a bearing that satisfies the dimensions specified in the ISO standard or the JIS standard. For example, the dimensions of radial bearings other than tapered roller bearings are specified in ISO15 or JIS B 1512-1.

[0029] Although the rolling bearing 1 is configured as a deep groove ball bearing in the above example, the rolling bearing 1 is not limited to a deep groove ball bearing.

[0030] The sensor unit 2 is fixed to the first bearing ring 4 .

[0031] The first bearing ring 4 is usually arranged as a stationary ring, and the second bearing ring 5 is usually arranged as a rotating ring.

[0032] The first raceway 4 is an outer race having a raceway surface 10 on its inner circumference. The second raceway 5 is an inner race having a raceway surface 11 on its outer circumference. Each rolling element 6 is a ball that rolls between the raceway surfaces 10, 11.

[0033] The first bearing ring 4 has a circumferential surface portion 12 on its inner circumference, which is press-fitted into the sensor unit 2. The circumferential surface portion 12 is made of a cylindrical surface extending in the circumferential direction. Hereinafter, the diameter of an imaginary cylindrical surface inscribed in the circumferential surface portion 12 is defined as the inner diameter d.

[0034] As shown in FIG. 4, the first raceway 4 has a width surface portion 13 located at one end of the axial width of the first raceway 4 (the right end in FIG. 4), a chamfered portion 14 that removes the corner between the width surface portion 13 and the peripheral surface portion 12, a step portion 15 that supports the sensor unit 2 in the axial direction, and a recessed portion 16 that is recessed in the axial direction between the step portion 15 and the peripheral surface portion 12.

[0035] The width surface portion 13 and the step portion 15 each have a flat surface that extends over the entire circumferential direction and in the radial direction.

[0036] The step portion 15 abuts against the side surface at the other axial end (the left end in Figure 4) of the sensor unit 2, properly determining the axial positional relationship between the sensor unit 2 and the first bearing ring 4 and restricting the sensor unit 2 from tilting in the radial direction.

[0037] As shown in Fig. 2, a certain distance is ensured between the sensor unit 2 and the rolling elements 6. This distance is set so that the sensor unit 2 and the rolling elements 6 do not come into contact with each other even if there is axial displacement due to the internal bearing gap of the rolling bearing 1. The cage 7 is a crown-shaped cage that has a ring portion only on the side opposite the sensor unit 2 (the side going away from the sensor unit 2, the left side in Fig. 2) with respect to each rolling element 6. The sensor unit 2 does not have any part that protrudes from the rolling bearing 1 in the axial direction.

[0038] 4, the recessed portion 16 forms a space for reliably avoiding interference with the sensor unit 2. It is also possible to omit the formation of the recessed portion 16.

[0039] The sensor unit 2 has a circuit board 17 and a holder 18 that holds the circuit board 17.

[0040] The circuit board 17 is made of a printed circuit board on which the above-mentioned electric circuits are formed.

[0041] The holder 18 is an annular body that is fixed to the peripheral surface portion 12 by press fitting, and in this fixed state, determines a predetermined position of the circuit board 17 relative to the first race 4 .

[0042] The holder 18 has an annular side portion 19 extending in the radial direction, and a fitting portion 20 extending in the axial direction from the side of the annular side portion 19 closer to the first race 4, which are integrally formed without any seam.

[0043] 4 and 5, the entire holder 18 is composed of a holding member 21. The holding member 21 is made of a single metal plate and is formed by press working.

[0044] The annular side portion 19 is shaped like an annular plate that extends straight in the radial direction around the entire circumferential direction. The side surface at one axial end (the right end in FIG. 4) of the annular side portion 19 forms a surface portion for axially supporting the circuit board 17. The side surface at the other axial end (the left end in FIG. 4) of the annular side portion 19 forms a surface portion for axially abutting against the step portion 15 of the first race 4.

[0045] The fitting portion 20 comprises a cylindrical wall 22 that continues around the entire circumferential direction on one axial end side of the annular side portion 19, a plurality of protrusions 23 that are spaced apart circumferentially and protrude from the cylindrical wall 22 towards the one axial end side, and a plurality of arc walls 24 that protrude from the cylindrical wall 22 towards the one axial end side between each of the circumferentially adjacent protrusions 23, 23 (see Figure 6).

[0046] As shown in Figures 1 and 6, the protrusion 23 is circumferentially and radially disconnected from parts of the holder 18 other than the protrusion 23, and consists of a cantilever portion that is higher radially toward the side closer to the peripheral portion 12 than the protrusion 23.

[0047] The multiple protrusions 23 are provided at equal intervals in the circumferential direction so as to have a radial interference δr with the peripheral surface portion 12 .

[0048] The projection 23 is made up of an inclined region that increases in diameter from the cylindrical wall 22 toward one axial end, and a straight region that extends further in a straight line in the axial direction from the one axial end of the inclined region. The straight region of the projection 23 is provided with a radial end face 25 that has a shape that follows the peripheral surface portion 12 in the axial and circumferential directions.

[0049] 7 shows a state in which the sensor unit 2 and the first race 4 are separated. When the sensor unit 2 is in a standalone state, the diameter of an imaginary cylindrical surface circumscribing the multiple protrusions 23 is taken as a circumscribing circle diameter Dp, and the diameter of an imaginary cylindrical surface circumscribing the parts of the fitting portion 20 other than the protrusions 23 is taken as a circumscribing circle diameter Do. The parts circumscribing the circumscribing circle diameter Do are the cylindrical wall 22 and the multiple arc walls 24.

[0050] The outer circumferential diameter Do is set to be smaller than the inner diameter d of the circumferential surface portion 12. The outer circumferential diameter Dp is set to be larger than the outer circumferential diameter Do and further larger than the inner diameter d. That is, it is set such that Do < d < Dp. The radial tightening margin δr corresponds to the difference between (Dp - d).

[0051] The sensor unit 2 does not have a portion provided with a diameter larger than the outer circumferential diameter Dp. The sensor unit 2 shown in FIGS. 1 to 3 is fixed to the first raceway ring 4 only by press-fitting a plurality of protrusions 23 into the circumferential surface portion 12.

[0052] By changing the number, circumferential width, axial length, and radial tightening margin δr of the protrusions 23 in the circumferential direction, the holding force of the sensor unit 2 with respect to the first raceway ring 4 (the frictional force for fixing the sensor unit 2 to the first raceway ring 4) can be changed.

[0053] Here, the case where the protrusions 23 are provided at equal intervals in the circumferential direction by 12 is illustrated. However, the shape, number, circumferential width, axial length, and arrangement of the protrusions, as well as the radial tightening margin with respect to the circumferential surface portion, may be appropriately determined so that the axial pulling force of the sensor unit with respect to the first raceway ring becomes a predetermined value or more while the deformation of the required portions in the first raceway ring and the sensor unit is within a predetermined range. For example, the deformation of the raceway surface 10 is within a predetermined range, and the strain and inclination of the annular side portion 19 of the sensor unit 2 are within a predetermined range, etc. can be mentioned.

[0054] The circumferential surface portion 12 is formed on the first raceway ring 4 by machining. Therefore, the dimensional tolerance of the inner diameter d of the circumferential surface portion 12 shown in FIG. 7 becomes relatively small. On the other hand, since the holder 18 is composed of the holding member 21 which is a press-formed product, it is difficult to manage the dimensional tolerances of the outer circumferential diameter Dp and the outer circumferential diameter Do to be smaller than those in the case of machining.

[0055] The plurality of protrusions 23 can be formed, for example, by punching the peripheral edge of a circular metal plate in a radially grooved shape at equal intervals in the circumferential direction, and further bending the cantilever-like portions between the punched grooves to form an inclined region and a straight region, and forming the cylindrical wall 22 and the arc wall 24 by cylindrical drawing.

[0056] Although it also depends on the sizes of the outer circumferential diameter Dp and the outer circumferential diameter Do, on the premise that Do < d < Dp is satisfied, for example, the outer circumferential diameter Dp can be set to a value 0.03 mm to 0.2 mm larger than the outer circumferential diameter Do, and the outer circumferential diameter Do can be set to a value 0.03 mm to 1 mm smaller than the inner diameter d.

[0057] When the sensor unit 2 is in the single state shown in FIG. 7, the inclined region of the protrusion 23 includes a portion with a larger diameter than the inner diameter d. However, as shown in FIG. 4, when in the fixed state where the radial end face 25 is in contact with the circumferential surface portion 12, the inclined region of the protrusion 23 is not in radial contact with the first raceway ring 4. The inclined region of the protrusion 23 is a portion for smoothly deflecting the protrusion 23 radially toward the side away from the circumferential surface portion 12 (the side far from the circumferential surface portion 12) by axial contact with the first raceway ring 4 during the press-fitting process of the sensor unit 2 and the first raceway ring 4.

[0058] Here, let the axial region W be the region where the sensor unit 2 fixed to the circumferential surface portion 12 and the first raceway ring 4 face each other in the radial direction. The axial region W corresponds to the axial interval between the stepped portion 15 and the width surface portion 13. In the axial region W, the contact between the protrusion 23 and the circumferential surface portion 12 is only between the radial end face 25 and the circumferential surface portion 12. The radial end face 25 is in axial contact with the circumferential surface portion 12 with a width only in the region on the side of the rolling element 6 opposite to the axial region W (the region far from the rolling element 6, the right side from the center of the axial region W in FIG. 4).

[0059] Also, in the axial region W, a radial gap g (see also FIG. 1) is provided between all parts except the contact portions of the plurality of protrusions 23 of the sensor unit 2 and the circumferential surface portion 12 and the first raceway ring 4. Therefore, the outer circumferences of the cylindrical wall 22 and the annular side portion 19, which are portions of the sensor unit 2 closer to the rolling element 6 side axially than the protrusion 23, are clearance-fitted with the first raceway ring 4.

[0060] As shown in FIGS. 1, 5, and 6, the aforementioned circuit board 17 includes a board 26, one or more sensors 27, 28 mounted on the board 26, a wireless communication circuit 29 mounted on the board 26, and a power supply circuit 30 mounted on the board 26.

[0061] The substrate 26 is made of a printed wiring board. The substrate 26 is in the shape of an arc plate that is short in the radial direction and long in the circumferential direction. As shown in Figures 4 and 6, the substrate 26 is fixed at a position radially away from the fitting portion 20. Sensors 27, 28, a wireless communication circuit 29, etc. are mounted on the substrate surface on one axial end side of the substrate 26 (the right end in Figure 4).

[0062] 5 and 6, the substrate 26 is fixed to the annular side portion 19 by a plurality of screws 31. It is also possible to fix the substrate 26 and the annular side portion 19 by adhesion using an adhesive, an adhesive sheet, or the like.

[0063] The sensors 27 and 28 each consist of a circuit that converts the above-mentioned physical or chemical quantities into an electric signal. The sensor 27 is, for example, an acceleration sensor that detects radial or axial acceleration to monitor vibration of the rolling bearing 1. The sensor 28 is, for example, a temperature sensor to monitor the temperature of the bearing 2.

[0064] The wireless communication circuit 29 is a communication circuit that converts predetermined information, such as the detection results of the sensors 27 and 28, into radio waves and radiates the radio waves from the antenna 32. The wireless communication circuit 29 complies with a predetermined communication protocol and is generally modular. To avoid a decrease in wireless communication performance, the antenna 32 is not in contact with other members, such as a sealant.

[0065] The power supply circuit 30 is made up of a circuit that converts AC power generated by the stator 9 as the magnetic ring 8 shown in FIGS. 1, 2 and 4 rotates into DC power used by the circuit board 17 .

[0066] The magnetic ring 8 is a rotor that generates a rotating magnetic field for the stator 9. The magnetic ring 8 is fixed to the second race 5.

[0067] The magnetic ring 8 has a magnet 33 magnetized with alternating north and south poles in the circumferential direction, and a core metal 34. The magnet 33 is formed of magnetic rubber extending in the circumferential direction. The magnet 33 is bonded to the core metal 34 all around in the circumferential direction. Vulcanization bonding can be used as the bonding method. The core metal 34 has a flange portion to increase its rigidity.

[0068] The magnetic ring 8 is fixed to the outer periphery of the second raceway 5. The fixing means is press-fitting, adhesive bonding, or a combination of both. A notch 35 that is recessed in the axial and radial directions is formed around the entire periphery of the outer periphery of the second raceway 5 at one axial end (the right end in FIG. 2). The flange portion of the magnetic ring 8 is contained within the area radially opposed to the notch 35, and the magnetic ring 8 does not have a portion that protrudes axially from the rolling bearing 1.

[0069] Stator 9 is a stator that guides the magnetic flux emitted from magnetic ring 8 with a yoke structure and induces an AC voltage in coil 36 within the yoke structure. Stator 9 is provided in sensor unit 2 so as to face magnetic ring 8 with an air gap between them. The yoke structure is composed of holding member 21 and yoke member 37 combined with holding member 21, as shown in Figs. 4 to 6.

[0070] In order to allow the holding member 21 and the yoke member 37 to function as a yoke, the holding member 21 and the yoke member 37 are each made of a magnetic material such as a steel plate.

[0071] The retaining member 21 has an extended side portion 38 extending radially from the annular side portion 19 toward the second raceway 5, and a first claw pole portion 39 extending from the extended side portion 38 toward one axial end side (the right side in Figure 4) at a regular interval in the circumferential direction, which are integrally formed without any seams.

[0072] The yoke member 37 has, seamlessly and integrally, an annular portion 40 facing the fitting portion 20 at a radial distance, a side circumferential portion 41 extending radially from one axial end portion (the right end portion in FIG. 4) of the annular portion 40 toward the second race 5, and a second claw pole portion 42 extending circumferentially from the side circumferential portion 41 toward the other axial end portion (the left side portion in FIG. 4) at a constant interval. The overall shape of the yoke member 37 is formed by press molding.

[0073] The first claw pole portion 39 and the second claw pole portion 42 face each other in the radial direction with an air gap between them and the magnet 33 shown in Fig. 1 and Fig. 4. As shown in Fig. 6, the first claw pole portion 39 and the second claw pole portion 42 are arranged in opposite directions in the axial direction and alternately arranged in the circumferential direction. A circumferential air gap is formed between the first claw pole portion 39 and the second claw pole portion 42 that are adjacent in the circumferential direction. The total number of the first claw pole portions 39 and the second claw pole portions 42 is equal to the number of poles (the total number of north poles and south poles) of the magnet 33 shown in Fig. 1.

[0074] As shown in Fig. 5, arc-shaped holes 43 penetrating between both side surfaces of the retaining member 21 are formed at multiple locations in the circumferential direction. The annular portion 40 has protrusions 44 that fit into the inner surfaces of the holes 42. As shown in Figs. 4 and 6, most of the annular portion 40, except for the protrusions 44, is abutted against the extended side portion 38 in the axial direction.

[0075] As shown in Fig. 5, the coil 36 is wound around a bobbin 45. As is clear from Figs. 4 to 6, the coil 36 and the like are arranged all around the circumference in the space surrounded by the extended side portion 38, the peripheral side portion 41, the annular portion 40, the first claw pole portion 39, and the second claw pole portion 42.

[0076] At least a portion of the surface of the coil 36 and the bobbin 45 may be in contact with the claw pole portions 39, 41, the extended side portion 38, and the peripheral side portion 41. When protecting the coil 36 for the purposes of insulation, heat resistance, dust resistance, moisture resistance, and chafing prevention, a varnish treatment may be employed in which the coil 36 is immersed in varnish or coated by dripping varnish onto the coil 36. Also, the bobbin 45 may be omitted.

[0077] The magnetic flux from the N pole of the magnet 33 shown in FIG. 1 and FIG. 4, for example, enters the extended side portion 38 (or the circumferential side portion 41) from the first claw pole portion 39 (or the second claw pole portion 42) which is a magnetic pole, goes around the coil 36 to reach the circumferential side portion 41 (or the extended side portion 38) via the annular portion 40, and returns to the S pole of the magnet 33 via the adjacent second claw pole portion 42 (or the first claw pole portion 39). When the positions of the N pole and the S pole of the magnet 33 are exchanged with the relative rotation of the first race 4 and the second race 5, the direction of the magnetic flux is reversed. The alternating magnetic field thus generated generates an AC voltage at both ends of the start and end of the winding of the coil 36. Although a radial type claw pole type generator has been exemplified as the generator 3, it is possible to change to another type of generator.

[0078] As shown in FIG. 6, the annular side portion 19, the fitting portion 20, and the annular portion 40 form an opening for accommodating the circuit board 17. This opening is closed by a cover 46 as shown in FIG. 3 and FIG. 4. The cover 46 is fixed to the circuit board 17 in a non-contact state. The internal space between the cover 46 and the circuit board 17 is filled with air. Because there is a gap between the protrusion 23 and the arc wall 24, it is preferable to insert the cover 46 to the inside of the cylindrical wall 22 to improve the sealing performance. For this reason, the outer periphery of the cover 46 is fitted into the cylindrical wall 22. In addition, the inner and outer peripheral portions of the cover 46 are butted against the annular side portion 19 in the axial direction to improve the sealing performance and the axial positioning of the cover 46. If the cover 46 is not fitted so deeply, it is also possible to position the circuit board 17 by contacting it with the cylindrical wall 22. The area between the cover 46 and the fitting portion 20 and the area between the cover 46 and the annular portion 40 may be sealed with a sealant.

[0079] The cover 46 is made of resin that does not contain metal. Even if the holding member 21 and the yoke member 37 shown in Fig. 5 are made of metal, the cover 46 shown in Figs. 3 and 4 has radio wave transparency, so wireless communication using the antenna 32 shown in Fig. 6 is possible. It is also possible to seal the circuit board 17 by filling the above-mentioned opening with a sealant without using the cover 46 shown in Fig. 4. In this case, since the antenna 32 shown in Fig. 6 is covered with the sealant, it is preferable to use a sealant with a low relative dielectric constant, such as a resin, to suppress deterioration of the radio wave characteristics of the antenna 32 due to the sealant.

[0080] When the circuit board 17 is covered with a cover 46 as shown in Fig. 4 to put the antenna 32 out of contact with other members, it is possible to obtain good radio wave characteristics of the antenna 32 as shown in Fig. 6. In this case, when the vibration caused by the rolling bearing 1 is detected by the sensor 27, the sensor 27 is not in contact with other members such as a sealant, so that the vibration can be easily detected accurately by the sensor 27.

[0081] Both ends of the coil 36 are connected to terminals 47 provided on the substrate 26 through small wiring holes formed in the annular portion 40. The input end of the power supply circuit 30 is the terminal 47. The power sources of the sensors 27, 28 and the wireless communication circuit 29 are each the output end of the power supply circuit 30. This bearing device is capable of performing detection and wireless communication by the circuit board 17 using the generator 3 as a power source, so that the sensor unit 2 can be made wireless. An emergency battery may be mounted on the substrate 26.

[0082] In assembling the sensor unit 2, as shown in FIG. 5, the bobbin 45 around which the coil 36 is wound is placed between the extended side portion 38 and the peripheral side portion 41, and the holding member 21 and the yoke member 37 are assembled in the axial direction, and at this time, each protrusion 44 of the yoke member 37 is inserted into the corresponding hole 43 of the holding member 21. This insertion ensures that the holding member 21 and the yoke member 37 are coaxial with each other, and the first claw pole portion 39 and the second claw pole portion 42 are arranged alternately in a predetermined phase with a gap in the circumferential direction. Therefore, the holding member 21 and the yoke member 37 can be assembled appropriately without using a jig. It is preferable that the holes 43 and the protrusions 44 are each formed in three or more places.

[0083] After this assembly, protrusion 44 is fixed to the inner surface of hole 43. This fixing means may be, for example, press fitting, bonding, laser welding, or a combination of these. It is also possible to omit protrusion 44 and hole 43. In this case, after coaxial alignment and phase alignment of the holding member and the yoke member are performed using a jig (not shown), the annular portion of the yoke member and the butting portion of the holding member may be bonded, or laser welded from the outer periphery of the annular portion, or a combination of these may be used for fixing.

[0084] After the holding member 21 and the yoke member 37 are combined as described above, the process of mounting the circuit board 17 is performed as shown in Fig. 6. Here, the circuit board 17 is fixed onto the annular side portion 19 using a plurality of screws 31. At this time, the board surface opposite the mounting surface for electronic components such as the sensor 27 faces the annular side portion 19. To insulate the holding member 21 and the circuit board 17 from each other, an insulating sheet such as a polyimide film (not shown) may be interposed between the circuit board 17 and the annular side portion 19.

[0085] After the circuit board 17 is fixed onto the annular side portion 19, a sealing process is performed to protect the circuit board 17. Here, as shown in Figures 4 and 7, the outer periphery of the cover 46 is fitted onto the inner periphery of the cylindrical wall 22 of the fitting portion 20, and the inner periphery of the cover 46 is fitted onto the outer periphery of the annular portion 40. At this time, the inner and outer periphery edges of the cover 46 butt against the annular side portion 19 in the axial direction, thereby determining the axial position of the cover 46. There is no particular limit to the means for fixing the cover 46, but an adhesive, for example, can be used as the fixing means.

[0086] In addition, when filling the gap between the fitting portion 20 and the annular portion 40 without using the cover 46, an appropriate sealant may be applied in advance to the gap between each protrusion 23 and the arc wall 24 to prevent the sealant from leaking from this gap.

[0087] 7, the sensor unit 2 is assembled and can be press-fitted into the first race 4. In this state, a press-fitting process is performed to fix the sensor unit 2 to the first race 4. Here, the sensor unit 2 and the first race 4 are coaxially arranged, and the multiple protrusions 23 are press-fitted into the peripheral surface portion 12.

[0088] In this press-fitting process, when the sensor unit 2 and the first race 4 are first assembled, only the area of ​​the outer periphery of the sensor unit 2 that is less than the circumscribed circle diameter Dp is inserted into the first race 4, so that the sensor unit 2 is inserted straight into the axial direction of the peripheral surface portion 12 without contacting the first race 4. In this way, the annular side portion 19 and the cylindrical wall 22 of the fitting portion 20 are completely positioned inside the peripheral surface portion 12, and after more than half of the axial width of the sensor unit 2 (corresponding to half of the axial area W) enters the inner side of the peripheral surface portion 12, only the inclined area of ​​the protrusion 23 shown in FIG. 4 comes into contact with the chamfered portion 14 or the boundary between the chamfered portion 14 and the peripheral surface portion 12. After this, as the contact position of the inclined area of ​​the protrusion 23 with respect to the boundary changes with the progress of insertion, the protrusion 23 elastically bends in the radial direction away from the peripheral surface portion 12. When the inclined region of the projection 23 has passed over the boundary, the radial end face 25 of the straight region of the projection 23 reaches the peripheral surface portion 12, and the inclined region of the projection 23 is out of contact with the first raceway 4. After this, the radial end face 25 of the projection 23 and the peripheral surface portion 12 continue to fit together in a tight fit state, and the contact area between the radial end face 25 and the peripheral surface portion 12 expands in the axial direction. When the annular side portion 19 eventually abuts against the step portion 15 in the axial direction, the press-fitting of the sensor unit 2 into the first raceway 4 is completed, as shown in Figures 1 to 4, and the sensor unit 2 is firmly fixed to the first raceway 4.

[0089] In this way, during the entire period of the press-fitting process, the sensor unit 2 contacts the first race 4 only through the multiple protrusions 23, and there is a radial gap between all parts of the sensor unit 2 other than the protrusions 23 and the first race 4, so even if the dimensional tolerance of the holder 18 is larger than that of a machined product, the axial pressing load required for performing the press-fitting process is prevented from becoming excessive. In other words, adverse effects on the performance of the rolling bearing 1 and the sensor unit 2 are prevented. For example, it is possible to prevent adverse effects such as the raceway surface 10 of the first race 4 being distorted and deforming, shortening the life of the rolling bearing 1 from the rated life, increasing the operating noise of the rolling bearing 1, and deforming the holder 18 of the sensor unit 2, reducing the detection accuracy of the sensors 27 and 28.

[0090] When the sensor unit 2 is fixed to the first raceway 4 by pressing the fitting portion 20 of the sensor unit 2 into the peripheral surface portion 12 of the first raceway 4 in the axial direction, the sensor unit 2 and the first raceway 4 are arranged coaxially. Since the first raceway 4 and the second raceway 5 constitute the rolling bearing 1, the sensor unit 2 is also arranged coaxially with the second raceway 5.

[0091] In the ring-shaped space radially sandwiched between the first raceway 4 and the second raceway 5, the circuit board 17, the stator 9, and the magnetic ring 8 are arranged in this order in a radially opposing relationship so as not to overlap in the axial direction, allowing these to be arranged thinly in the axial direction. This makes it possible to provide a bearing device of the same size as the rolling bearing 1 configured as a standard bearing.

[0092] In addition, since the radial gap fluctuation between the magnetic ring 8 fixed to the second raceway 5 of the radial bearing and the stator 9 of the sensor unit 2 similarly fixed to the first raceway 4 is small, a stable amount of power generation can be ensured by the generator 3.

[0093] In addition, the sensor unit 2 fixed to the first race 4 can be pulled out from the first race 4 without damaging each protrusion 23 by elastically bending the protrusion 23 consisting of the cantilever beam part in the radial direction away from the peripheral surface part 12. Since the contact part between each protrusion 23 consisting of the cantilever beam part and the peripheral surface part 12 is exposed from between the outer periphery of the sensor unit 2 and the inner periphery of the first race 4 toward the reversible moving body 6 in the axial direction, it is possible to bend the protrusion 23 in the radial direction away from the peripheral surface part 12 by inserting an appropriate jig between the protrusion 23 and the peripheral surface part 12. After the sensor unit 2 is pulled out and inspected, it can be reused by performing the press-fitting process again to fix it to the first race 4.

[0094] This bearing device (see Figures 1, 4, 6 and 7) is as described above and comprises a rolling bearing 1 having a first raceway 4, a second raceway 5 and two or more rolling elements 6 arranged between the first raceway 4 and the second raceway 5, and a sensor unit 2 having a circuit board 17 with sensors 27, 28 and a holder 18 for holding the circuit board 17, with the sensor unit 2 fixed to a peripheral portion 12 on the inner circumference of the first raceway 4.

[0095] In particular, this bearing device has a plurality of protrusions 23 spaced apart in the circumferential direction so that the holder 18 has a radial interference δr with the peripheral surface portion 12, and the sensor unit 2 is fixed to the first race 4 only by pressing the plurality of protrusions 23 into the peripheral surface portion 12, so that when fixing the sensor unit 2 to the first race 4 by the above-mentioned press-fitting process, it is only necessary to press the plurality of protrusions 23 of the holder 18 into the peripheral surface portion 12 of the first race 4 at a plurality of points in the circumferential direction, and the pressing load required for pressing is smaller than when the holder and the first race are pressed into each other at their cylindrical surfaces. As a result, this bearing device can reduce deformation of both the holder 18 of the sensor unit 2 and the peripheral surface portion 12 of the first race 4 while fixing the sensor unit 2 by pressing the holder 18 of the sensor unit 2 into the peripheral surface portion 12 of the first race 4.

[0096] Furthermore, in this bearing device, the protrusions 23 consist of cantilever portions that are disconnected circumferentially and radially from other portions of the holder 18 other than the protrusions 23. Therefore, when the protrusions 23 are pressed into the peripheral surface portion 12 of the first raceway 4, they bend and elastically exert a radial repulsive force, and the sensor unit 2 can be fixed by pressing the multiple protrusions 23 into the peripheral surface portion 12. Even if the tolerance of the radial interference δr is large, this can be absorbed by the bending deformation of the protrusions 23, and deformation of the first raceway 4 and other portions of the holder 18 other than the protrusions 23 can be reduced.

[0097] In addition, in this bearing device, the holder 18 has an annular side portion 19 extending radially and an engagement portion 20 protruding axially from the annular side portion 19, the engagement portion 20 has protrusions 23 at multiple locations evenly spaced circumferentially, and the circuit board 17 is attached to the annular side portion 19 without contacting the multiple protrusions 23.Therefore, the deformation of the holder 18 and the first raceway 4 due to the pressing of the multiple protrusions 23 into the peripheral surface portion 12 of the first raceway 4 is made circumferentially equal, and interference between the deformed protrusions 23 and the circuit board 17 is avoided, preventing any impact on the performance of the sensor unit 2 and the rolling bearing 1.

[0098] In addition, in this bearing device, the protrusions 23 contact the circumferential surface portion 12 only in the area on the reversible moving body 6 side of the axial region W where the sensor unit 2 and the first raceway 4 are radially opposed. Therefore, the contact between the protrusions 23 and the circumferential surface portion 12 is reduced compared to when multiple protrusions 23 are in contact with the circumferential surface portion 12 over the entire axial region W, making it possible to further reduce the pressing load required for pressing in. In addition, contact between the sensor unit 2 and the first raceway 4 is avoided until the protrusions 23 contact the circumferential surface portion 12 during the pressing-in process, thereby preventing the sensor unit 2 from being pressed in at an angle relative to the circumferential surface portion 12.

[0099] Furthermore, since the protrusion 23 of this bearing device contacts the peripheral surface portion 12 with a certain width in the axial direction, even if the arrangement of the protrusion 23 is limited to the side of the reversible moving body 6 in the axial region W, it is possible to easily stabilize the posture of the sensor unit 2 relative to the first raceway 4.

[0100] Furthermore, in this bearing device, a portion of the sensor unit 2 that is axially closer to the rolling body 6 than the protrusion 23 is clearance-fitted into the first raceway. Therefore, by providing a clearance-fit portion (radial gap g) between the sensor unit 2 and the first raceway 4, radial contact between the sensor unit 2 and the first raceway 4 is reliably reduced at a stage before the protrusion 23 of the sensor unit 2 reaches the peripheral surface portion 12 during the pressing-in process, thereby reducing the pressing load required for pressing.

[0101] A bearing device according to a second embodiment of the present invention is shown in Figures 8 and 9. Note that, in the following, only the differences from the first embodiment will be described.

[0102] In the bearing device according to the second embodiment, the shape and arrangement of the projections 51 of the holder 50 are changed.

[0103] The protrusion 51 is continuous with the cylindrical wall 52, and is also continuous with arc walls 53 on both circumferential sides of the protrusion 51. The protrusion 51 has an inclined region 54 with a short width in the axial direction from the cylindrical wall 52, and also has, in a straight region, a radial end face 55 in the form of an arc surface that extends along the axial direction and has a larger curvature than the cylindrical wall 52 and the arc wall 53. Such a protrusion 51 can be formed, for example, by simply extruding the peripheral portion of a circular metal plate to partially expand it.

[0104] The rigidity of the protrusions 51 against radial deformation is higher than that of a cantilever beam. The number of protrusions 51 is reduced to six to avoid an increase in the pressing load required for press-fitting. The number of protrusions 51 and the shape of the bulge can be changed as appropriate.

[0105] In the bearing device of the second embodiment, the protrusion 51 consists of a protruding portion that bulges out from a part of the holder 50. Therefore, even if the tolerance of the radial interference δr (see also FIG. 1) is large, the protrusion 51 can absorb the deformation by flattening in the radial direction, thereby reducing deformation of the first race 4 and parts of the holder 50 other than the protrusion 51.

[0106] FIG. 10 shows a bearing device according to a third embodiment, which is yet another example of the present invention.

[0107] In the bearing device according to the third embodiment, the first raceway 62 to which the sensor unit 61 is fixed relative to the rolling bearing 60 is changed to an inner raceway. With this change, a peripheral surface portion 63 is formed on the outer periphery of the first raceway 62. In addition, the magnetic ring 64 is fixed to the inner periphery of the second raceway 65. A stator 66 is provided on the outer periphery of the sensor unit 61, and a plurality of protrusions 67 are provided on the inner periphery of the sensor unit 61. A radial interference is set based on the diameter difference between the diameter of an imaginary cylindrical surface inscribed in the plurality of protrusions 67 and the outer diameter of the peripheral surface portion 63. The value of the diameter difference can be set in the same way as in the first embodiment. The sensor unit 61 is fixed only by press-fitting the plurality of protrusions 67 into the peripheral surface portion 63 on the outer periphery of the first raceway 62. The bearing device according to the third embodiment can reduce deformation of the first raceway 62, which is the inner ring.

[0108] A bearing device according to a fourth embodiment, as yet another example of the present invention, is shown in Figures 11 and 12. Note that the fourth embodiment is a further modification of the second embodiment (see Figure 8), and therefore only the differences from the second embodiment will be described here.

[0109] A notch 56 is formed along the protrusion 51 between the cylindrical wall 52 and the protrusion 51 of the holder according to the fourth embodiment. The notch 56 penetrates in the radial direction so as to separate the inclined region 54 of the protrusion 51 from the cylindrical wall 52. Both circumferential ends of the notch 56 are located at positions circumferentially separated from the protrusion 51. This is to prevent stress concentration from occurring at the corners of the notch 56 when the protrusion 51 deforms in the radial direction.

[0110] In the bearing device of the fourth embodiment, a notch 56 is formed along the protrusion 51 consisting of a protruding portion, and therefore, at the location where the notch 56 is formed, there is less resistance to radial deformation of the protrusion 56, making it easier for the protrusion 56 to deform radially when pressed into the peripheral surface portion of the first raceway (see Figure 1).

[0111] 11 and 12, since the inclined region 54 of the projection 51 is along the circumferential direction, the notch 56 also extends in the circumferential direction, but if the projection shape of the projection is different, the direction in which the notch extends and the length can be changed to suit the shape. For example, if the projection is a hemispherical projection, the notch can be formed along both axial ends or both circumferential ends of the hemispherical shape.

[0112] In addition, although an example has been shown in which the notches 56 are slit-shaped and penetrate in the radial direction, it is also possible to change the notches to groove-shaped ones. Groove-shaped notches that do not penetrate in the radial direction are suitable when there are concerns about the strength and processing aspects of the area around the protrusion.

[0113] 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. [Explanation of symbols]

[0114] 1,60 Rolling bearing 2,61 Sensor unit 4,62 First raceway 5,65 Second bearing ring 6 Rolling elements 12,63 Peripheral part 17 Circuit Board 18,50 Holder 19 Circular side 20 Fitting part 22,52 Cylindrical wall 23,51,67 protrusion 24,53 Circular Wall 25,55 Radial end face 27,28 Sensors 56 Notch δr Interference g Gap W axial area

Claims

1. a rolling bearing having a first raceway, a second raceway, and two or more rolling elements disposed between the first raceway and the second raceway; a sensor unit having a circuit board and a holder for holding the circuit board; In the bearing device, the sensor unit is fixed to one of an inner peripheral surface and an outer peripheral surface of the first raceway, the holder has a plurality of protrusions spaced apart in a circumferential direction so as to have a radial interference with the peripheral surface portion, A bearing device, wherein the sensor unit is fixed to the first race only by press-fitting the plurality of protrusions into the peripheral surface portion.

2. 2. The bearing device according to claim 1, wherein the projection is a cantilever portion that is disconnected in the circumferential and radial directions from portions of the holder other than the projection.

3. 2. The bearing device according to claim 1, wherein the projection is a protruding portion that bulges out from a portion of the holder.

4. 4. The bearing device according to claim 3, wherein a notch is formed along said projection.

5. The holder has an annular side portion extending in a radial direction and a fitting portion protruding in an axial direction from the annular side portion, The fitting portion has the protrusions at a plurality of locations that are evenly spaced apart in a circumferential direction, 5. The bearing device according to claim 1, wherein the circuit board is attached to the annular side portion in a state of not contacting the plurality of protrusions.

6. 5. A bearing device according to claim 1, wherein the protrusion and the peripheral surface portion are in contact only in an area on the reversible moving body side of an axial region in which the sensor unit and the first raceway face each other in a radial direction.

7. 7. The bearing device according to claim 6, wherein the projection is in contact with the peripheral surface portion with a certain width in the axial direction.

8. 5. The bearing device according to claim 1, wherein a portion of the sensor unit, which is axially closer to the rolling elements than the projection, is clearance-fitted into the first raceway ring.

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