Bearing device

Abstract

To provide a bearing device in which when a holder for sensors, etc. is fixed to a race, deformation of the race and the holder is reduced, and the holder is easily reused.SOLUTION: A first race 4 of a rolling bearing 1 comprises a fitting part 4c supporting a holder 8 on which a board 9a, sensors 9b and 9c, circuits 9d and 9e, etc. can be installed, in a radial direction, and a step part 4d supporting the holder 8 in an axial direction. The fitting part 4c and the holder 8 are clearance-fitted. At least one permanent magnet 12 for fixing the holder 8 to the first race 4 by a magnetic attraction force is arranged between the holder 8 and the race 4.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 a sensor or the like for detecting the condition of a rolling bearing is mounted on a substrate to form a sensor-equipped circuit board, the circuit board is held in a holder to assemble it into a sensor unit, and the sensor unit is fixed to a raceway ring.

[0003] When the sensor unit is equipped with a stator of a generator that supplies power to the circuit board, the holder may function as a yoke for the stator. Also, when detecting bearing vibrations, it may be preferable to position the holder with a predetermined degree of coaxiality with the bearing ring to detect the bearing condition. In such cases, the holder is an annular body that is fitted onto either the inner or outer circumference of the bearing ring.

[0004] Furthermore, there are 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 supply circuit on the board, a wireless communication circuit on the board, or multiple sensors on the board. In such cases, the holder is provided with an annular side portion extending radially and a fitting peripheral portion extending axially from the raceway side of the annular side portion, and a fixing structure is adopted in which the circuit board is attached to the annular side portion and the peripheral 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 holders described above are generally made of metal to ensure the strength to withstand press-fitting, and in particular, when the holder is to function as a yoke, they are made of an iron-based magnetic material.

[0006] For example, the sensor-equipped bearing device of Patent Document 1 has a holder that functions as a yoke, and a vibration sensor, temperature sensor, power supply circuit, wireless communication circuit, etc. are mounted on a circuit board that is long in the circumferential direction.The circuit board is attached to the side of the annular side of the holder that faces the rolling elements, and the circumferential part of the holder and the raceway are fitted and fixed together with their cylindrical surfaces. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-307435 Summary of the Invention [Problem to be solved by the invention]

[0008] When the cylindrical surfaces of the holder and the raceway are fitted and fixed together, as in the sensor-equipped bearing device of Patent Document 1, using an adhesive to fix them requires degreasing before bonding, which makes assembly of the bearing device complicated.

[0009] Pressing the cylindrical surfaces of the holder and bearing ring together can fix them more easily than using adhesives. However, excessive radial interference between the bearing ring and holder makes the press-fit difficult. Furthermore, the pressure load applied during press-fitting can cause deformation of the raceway surface and the holder, potentially adversely affecting the performance of the rolling bearing and sensor unit. In particular, when the holder is manufactured using a press or other method, the tolerance of the holder is larger than when manufactured using a machine, raising concerns that the press-fitting process will be difficult. Furthermore, if the bearing is damaged and the sensor unit is to be reused, the pressed-in holder must be removed from the bearing ring, which is difficult to do. Furthermore, the holder undergoes plastic deformation during removal, making it difficult to reuse.

[0010] In view of the above background, the problem that the present invention aims to solve is to provide a bearing device that reduces deformation of the raceway and holder when fixing a holder for a sensor or the like to the raceway, and that makes it easy to reuse the holder. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention employs Configuration 1, which is a bearing device comprising: a rolling bearing having a first raceway, a second raceway, and a plurality of rolling elements arranged between the first raceway and the second raceway; and a holder connected to the first raceway and capable of accommodating a substrate, sensor, circuit, etc., wherein the first raceway has a fitting portion that supports the holder radially and a step portion that supports the holder axially, and further comprising at least one permanent magnet arranged between the holder and the first raceway so as to fix the holder to the first raceway by magnetic attraction.

[0012] As in the above-described configuration 1, when the holder is fixed to the first bearing ring using the magnetic attractive force of the permanent magnet, the radial fit between the fitting portion of the first bearing ring and the holder is looser than when fixing is solely dependent on press fitting. This reduces deformation of the bearing ring and holder when fixing the sensor unit, and makes it easier to reuse the holder.

[0013] In the above configuration 1, configuration 2 can be adopted in which the fitting portion of the first bearing ring and the holder are loosely fitted, and the at least one permanent magnet is arranged to fix the holder to the first bearing ring by axial magnetic attraction force.

[0014] According to the above configuration 2, it is possible to eliminate the concern of deformation of the first raceway and holder when fixing the sensor unit, and to fix the holder to the first raceway by axial magnetic attraction force without being affected by the radial fitting clearance.

[0015] In the above configuration 1 or 2, a configuration 3 can be adopted in which the first bearing ring and the holder are each made of a magnetic material.

[0016] According to the above-mentioned configuration 3, the magnetic flux of the permanent magnet is guided by utilizing the first raceway ring and the holder, and the above-mentioned strong magnetic attraction force can be obtained.

[0017] In the above configuration 3, configuration 4 can be adopted in which at least one of the holder and the first bearing ring includes a recessed portion that is recessed axially relative to the step portion so that the permanent magnet can be embedded.

[0018] According to the above-mentioned configuration 4, the permanent magnet is embedded in the recess so that it does not get in the way when the holder is supported axially by the step portion of the first raceway, and is sandwiched axially between the first raceway and the holder to create a closed magnetic circuit between the permanent magnet, the holder, and the first raceway, thereby making it possible to obtain the aforementioned strong magnetic attraction force.

[0019] In the configuration 3 or 4, a configuration 5 can be adopted in which a pair of the permanent magnets are provided, adjacent to each other in the circumferential direction and arranged with opposite polarities.

[0020] According to the fifth aspect, a magnetic field is generated between the opposite poles of the pair of permanent magnets, so that the aforementioned strong magnetic attraction force can be obtained.

[0021] In any one of the above configurations 1 to 4, configuration 6 can be adopted, which includes the permanent magnet fixed to the first raceway and the permanent magnet fixed to the holder, and the permanent magnet fixed to the first raceway and the permanent magnet fixed to the holder are arranged so that their opposite poles face each other.

[0022] According to the sixth aspect, the permanent magnet on the first raceway ring side and the permanent magnet on the holder side attract each other, so that the aforementioned strong magnetic attraction force can be obtained.

[0023] In any one of the above configurations 1 to 6, a configuration 7 can be adopted in which the holder has a peripheral portion that fits into the fitting portion and a protrusion that protrudes radially from the peripheral portion, and the first raceway has a notch that forms an axial gap with the protrusion and fits snugly with the protrusion in the circumferential direction.

[0024] According to the above-mentioned configuration 7, the rotation of the holder relative to the first raceway can be prevented without rattle by the circumferential engagement between the notch portion and the protrusion portion, and when removing the holder from the first raceway, a tool can be inserted into the axial gap between the notch portion and the protrusion portion to apply an external force to the protrusion portion, thereby easily separating the holder from the first raceway.

[0025] In any one of the above configurations 1 to 7, the holder may be provided with a sensor unit having a sensor-equipped circuit board on which a substrate, a sensor, a circuit, etc. are attached.

[0026] Furthermore, in any one of the above configurations 1 to 7, if the holder is magnetic, it can be attracted directly by the magnetic force of a permanent magnet, and even if the main body of the holder is non-magnetic, a magnetic part can be provided in a part of the holder and that part can be attracted by magnetic force, or the main body of the holder can be made non-magnetic and a magnetic member can be placed on the opposite side of the permanent magnet of the holder and this magnetic member can be attracted by magnetic force, thereby sandwiching the holder between the permanent magnet and the magnetic member and fixing the holder. [Effects of the Invention]

[0027] As described above, by adopting the above configuration 1, the present invention can provide a bearing device that reduces deformation of the raceway and holder when fixing a holder for a sensor or the like to the raceway and makes it easy to reuse the holder. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a cross-sectional view showing a bearing device according to a first embodiment of the present invention; [Figure 2] FIG. 2 is a perspective view showing the bearing device of FIG. 1; [Figure 3] An exploded perspective view showing the sensor unit and rolling bearing of Figure 2 separated and the sensor unit cover removed. [Figure 4] FIG. 2 is a right side view showing the bearing device of FIG. 1 with the sensor unit removed. [Figure 5] FIG. 4 is a perspective view showing the yoke structure of the sensor unit of FIG. 3 in an exploded state. [Figure 6] FIG. 10 is a right side view showing a state in which a sensor unit of a bearing device according to a second embodiment of the present invention has been removed. [Figure 7] FIG. 10 is a cross-sectional view showing a bearing device according to a third embodiment of the present invention. [Figure 8] FIG. 8 is an exploded perspective view showing the bearing device of FIG. 7 with the sensor unit removed. [Figure 9] FIG. 10 is a left side view showing a holder of a bearing device according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view showing a bearing device according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] 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 9. FIG.

[0030] The bearing device shown in FIGS. 1 to 3 includes a rolling bearing 1, a sensor unit 2, and a generator 3.

[0031] Here, the circumferential direction centered on the bearing center axis of the rolling bearing 1 is referred to as the "circumferential direction," the direction along the bearing center axis is referred to as the "axial direction," and the direction perpendicular to the bearing center axis is referred to as the "radial direction."

[0032] The rolling bearing 1 has a first raceway 4, a second raceway 5, and a plurality of rolling elements 6 arranged between the first raceway 4 and the second raceway 5. These rolling elements 6 are held at equal intervals in the circumferential direction by a cage 7.

[0033] The sensor unit 2 is configured as a unit that incorporates 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 while fixed to the first bearing ring 4 and outputs the detection result to a predetermined destination. The sensor unit 2 has a holder 8 connected to the first bearing ring 4 and a sensor-equipped circuit board 9 attached to the holder 8.

[0034] The generator 3 comprises a magnetic ring 10 fixed to the second bearing ring 5 and a stator 11 facing the magnetic ring 10 across a magnetic gap, and the relative rotational motion between the first bearing ring 4 and the second bearing ring 5 is electromagnetically converted into alternating current by the magnetic ring 10 and the stator 11.

[0035] 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 meets the dimensions specified in an ISO or JIS standard. For example, the dimensions of radial bearings other than tapered roller bearings are specified in ISO15 or JIS B 1512-1.

[0036] 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.

[0037] As shown in Figures 1 and 3, the first bearing ring 4 is an outer ring having a raceway surface 4a on its inner periphery. The second bearing ring 5 is an inner ring having a raceway surface 5a on its outer periphery. Each rolling element 6 is a ball that rolls between the raceway surfaces 4a, 5a. Although the example shown is of a deep groove ball bearing as the rolling bearing 1, the rolling bearing 1 is not limited to a deep groove ball bearing and may be changed to various types of bearings such as an angular contact ball bearing, a cylindrical roller bearing, a tapered roller bearing, or a self-aligning bearing.

[0038] The first bearing ring 4 and the second bearing ring 5 are each made of an iron-based magnetic material such as seamless bearing steel.

[0039] The first bearing ring 4 has a width surface portion 4b located at one axial end (the right end in Figure 1; hereinafter, this one axial end will be simply referred to as the "right side") of both ends that define the axial width of the first bearing ring 4, an engagement portion 4c that radially supports the holder 8 at a position on the other axial side (the left side in Figure 1; hereinafter, this other axial side will be simply referred to as the "left side") of the width surface portion 4b and to the right of the raceway surface 4a, and a step portion 4d that axially supports the left-side side surface of the holder 8 at a position left of the engagement portion 4c and to the right of the raceway surface 4a.

[0040] The fitting portion 4c is a portion for positioning the holder 8 and the first bearing ring 4 with a predetermined degree of coaxiality. The fitting portion 4c is formed in the shape of a cylindrical surface along the axial and circumferential directions.

[0041] The step portion 4d is a portion that receives the holder 8 in the axial direction when fitting the holder 8 to the first bearing ring 4, determines the fitting stop position, and regulates the tilt of the holder 8 relative to the radial direction in the fitted state. The step portion 4d protrudes higher in the radial direction toward the second bearing ring 5 than the fitting portion 4c, and is formed in the shape of an annular surface that extends in the radial and circumferential directions.

[0042] A certain distance is maintained 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 will not come into contact even if there is axial displacement due to clearance inside the rolling bearing 1. The cage 7 is a crown-shaped cage that has a ring portion only on the left side of each rolling element 6. The entire sensor unit 2 is housed within the bearing width of the rolling bearing 1, and is also housed within the range of the cross-sectional height of the rolling bearing.

[0043] The holder 8 is made of a seamless magnetic material having a peripheral portion 8a that fits into the fitting portion 4c, an annular side portion 8b that protrudes radially from the left side of the peripheral portion 8a, and a protrusion 8c that protrudes radially from the right side of the peripheral portion 8a. The overall shape of the holder 8 is formed by press-molding an iron-based plate material.

[0044] The peripheral portion 8a is formed into a cylindrical plate shape along the circumferential direction. The outer diameter of the peripheral portion 8a is smaller than the diameter of an imaginary circle inscribed in the fitting portion 4c. This setting results in a loose fit between the peripheral portion 8a and the fitting portion 4c. There is no portion where the holder 8 has radial interference with the first bearing ring 4. Therefore, the fit between the holder 8 and the first bearing ring 4 does not deform the holder 8 or the raceway surface 4a of the first bearing ring 4. In other words, even if the dimensional tolerance of the holder 8 is larger than that of a machined product, there is no concern that this will have an adverse effect on the performance of the rolling bearing 1 or the sensor unit 2. For example, there will be no adverse effects, such as shortening the life of the rolling bearing 1 from its rated life due to distortion of the raceway surface 4a of the first bearing ring 4, increasing the operating noise of the rolling bearing 1, or deforming the holder 8, reducing the detection accuracy of the sensor.

[0045] The annular side portion 8b is formed in the shape of a circular ring plate extending in the radial direction. The left side surface of the annular side portion 8b contacts the step portion 4d. The circuit board 9 is disposed on the right side surface of the annular side portion 8b.

[0046] The protrusions 8c extend radially in a circumferential portion away from the second bearing ring 5. Although the example in which the protrusions 8c are arranged at four locations evenly spaced in the circumferential direction has been shown, they do not need to be evenly spaced in the circumferential direction, and the number of locations in the circumferential direction is not particularly limited.

[0047] The first bearing ring 4 has a notch 4e that fits snugly into the protrusion 8c of the holder 8 in the circumferential direction. The notch 4e is a portion that prevents circumferential displacement of the protrusion 8c and prevents circumferential rattle when the holder 8 rotates relative to the first bearing ring 4. The notch 4e is a groove that penetrates between the inner and outer circumferences of the first bearing ring 4 in a portion of the circumferential direction, has a groove depth on the left side of the width surface portion 4b, and intersects with the fitting portion 4c at one end of the groove length. The edges on both circumferential sides of the protrusion 8c fit snugly into both circumferential ends of the notch 4e in the circumferential direction. Although an example has been shown in which the notches 4e are arranged at four locations evenly spaced in the circumferential direction, they do not need to be evenly spaced in the circumferential direction, and the number of notches arranged in the circumferential direction is not particularly limited.

[0048] An axial gap g is secured between the protrusion 8c and the groove bottom surface of the notch 4e. The protrusion 8c does not protrude radially from the notch 4e. The axial gap g opens radially away from the second bearing ring 5. An appropriate tool (not shown), such as a flat-head screwdriver or bearing puller, can be inserted into the axial gap g and placed against the left side surface of the protrusion 8c to push the protrusion 8c to the right, or hooked onto the left side surface of the protrusion 8c to pull the protrusion 8c to the right.

[0049] Since it is possible to position the holder 8 radially relative to the first raceway 4 with the fitting portion 4c and the circumferential portion 8a, and to position (prevent rotation of) the holder 8 circumferentially relative to the first raceway 4 with the protrusion 8c and the notch 4e, the holder 8 can be fixed to the first raceway 4 by applying a holding force to the holder 8 that keeps the axial position of the holder 8 constant relative to the first raceway 4. Here, in order to fix the holder 8 in a state that allows it to be removed from the first raceway 4, magnetic force is used as the holding force mentioned above.

[0050] 1, 3, and 4, the first bearing ring 4 has a recessed portion 4f recessed to the left of the step portion 4d. The recessed portion 4f is a portion that forms a space for embedding the permanent magnet 12. The recessed portion 4f is bored in the shape of a circular hole in the axial direction from the step portion 4d.

[0051] The permanent magnet 12 is formed in a cylindrical shape that fits into the recessed portion 4f, and has magnetic pole faces on its right and left ends. The permanent magnet 12 is fixed in the recessed portion 4f with both its north and south pole faces facing the axial direction. The permanent magnet 12 may be, for example, a neodymium magnet, a samarium-cobalt magnet, a ferrite magnet, or an alnico magnet. The permanent magnet 12 is fixed in the recessed portion 4f by adhesive or the like. The fixing means may be any means that fixes the permanent magnet 12 so that it does not separate from the first bearing ring 4.

[0052] The axial length of the permanent magnet 12 is set to be equal to the hole depth of the recessed portion 4f. This setting is intended to position the pole face at the right end of the permanent magnet 12 and the step portion 4d on substantially the same plane. When the holder 8 is fitted into the fitting portion 4c and the left side surface of the holder 8 is axially butted against the step portion 4d, the permanent magnet 12 does not interfere with the holder 8, the step portion 4d is in axial contact with the entire surface of the holder 8, and the pole face at the right end of the permanent magnet 12 is in axial contact with or located very close to the left side surface of the holder 8. Although an example has been shown in which the recessed portions 4f are arranged at four locations evenly spaced circumferentially, they do not need to be evenly spaced circumferentially, and the number of recessed portions arranged circumferentially is not particularly limited.

[0053] When the periphery of the recessed portion 4f of the step portion 4d is butted against the left side surface of the annular side portion 8b in the axial direction, a closed magnetic circuit is generated that penetrates the permanent magnet 12 in the axial direction and circulates around the annular side portion 8b, the vicinity of the recessed portion 4f, and the periphery of the recessed portion 4f of the step portion 4d. Because the magnetic flux of the permanent magnet 12 does not escape from the vicinity of the annular side portion 8b and the recessed portion 4f, a strong axial magnetic attraction force of the permanent magnet 12 acting on the annular side portion 8b can be obtained. The magnetic attraction force of the four permanent magnets 12 evenly spaced around the circumference attracts the holder 8 to the left, up to the step portion 4d, and the sensor unit 2 is fixed to the first bearing ring 4.

[0054] The right-end magnetic pole face of each permanent magnet 12 fixed to the first bearing ring 4 may be either an N pole or an S pole. For example, the right-end magnetic pole faces of all the permanent magnets 12 fixed to the first bearing ring 4 may be unified as either an N pole or an S pole, or permanent magnets 12 whose right-end magnetic pole face is an N pole and permanent magnets 12 whose right-end magnetic pole face is an S pole may be arranged alternately in the circumferential direction.

[0055] In the illustrated example, the recesses 4f are circular to facilitate drilling, and cylindrical permanent magnets 12 are used to accommodate them. However, the shape of the permanent magnets is not particularly limited. In addition, in the illustrated example, at least one permanent magnet 12 is evenly spaced around each half of the circumference of the first bearing ring 4 to prevent the holder 8 from tilting due to magnetic attraction. However, the circumferential spacing and number of permanent magnets are not particularly limited. For example, permanent magnets of other shapes, such as rectangular, arc-shaped, or annular, may be used. Alternatively, an arc-shaped or annular recess extending circumferentially may be formed to secure one arc-shaped or annular permanent magnet. Essentially, the arrangement, number, and type of permanent magnets may be determined so that the magnetic attraction of one or more permanent magnets prevents the holder 8 from moving axially relative to the first bearing ring 4.

[0056] 1 is a printed circuit board on which the above-mentioned electric circuit is formed. As shown in FIG. 3, the circuit board 9 has a substrate 9a, one or more sensors 9b and 9c mounted on the substrate 9a, a wireless communication circuit 9d mounted on the substrate 9a, and a power supply circuit 9e mounted on the substrate 9a.

[0057] The substrate 9a is a printed wiring board. The substrate 9a is an arc-shaped plate that is short in the radial direction and long in the circumferential direction. Sensors 9b and 9c, a wireless communication circuit 9d, etc. are mounted on the right side of the substrate 9a.

[0058] 3, the substrate 9a is fixed to the annular side portion 8b by a plurality of screws 13. It is also possible to fix the substrate 9a and the annular side portion 8b by bonding them together using an adhesive, an adhesive sheet, or the like.

[0059] Sensors 9b and 9c each consist of a circuit that converts the aforementioned physical or chemical quantities into an electrical signal. Sensor 9b is, for example, an acceleration sensor that detects radial or axial acceleration to monitor vibrations of rolling bearing 1. Sensor 9c is, for example, a temperature sensor that monitors the temperature of rolling bearing 1.

[0060] The wireless communication circuit 9d is a communication circuit that converts predetermined information, such as the detection results of the sensors 9b and 9c, into radio waves and radiates them from an antenna. The wireless communication circuit 9d conforms to a predetermined communication protocol and is generally modular.

[0061] The power supply circuit 9e is a circuit that converts AC power generated by the stator 11 as the magnetic ring 10 shown in FIGS. 1 and 2 rotates into DC power used by the circuit board 9.

[0062] The magnetic ring 10 is a rotor that generates a rotating magnetic field for the stator 11. The magnetic ring 10 is fixed to the second bearing ring 5. The magnetic ring 10 consists of magnets that are magnetized with alternating north and south poles in the circumferential direction and a core metal that is bonded to the magnets around the entire circumferential direction. The core metal has a flange portion to increase its rigidity. The magnetic ring 10 is fixed to the second bearing ring 5 by press fitting, bonding, or a combination of these. A notch is formed around the entire circumferential direction on the right side of the second bearing ring 5 for locating the flange portion of the magnetic ring 10. The entire magnetic ring 10 is accommodated within the bearing width of the rolling bearing 1 and is also accommodated within the range of the cross-sectional height of the rolling bearing.

[0063] The stator 11 is a stator that guides the magnetic flux emitted from the magnetic ring 10 through a yoke structure and induces an AC voltage in the coil 11a within the yoke structure. The stator 11 is provided in the sensor unit 2 so as to face the magnetic ring 10 with an air gap between them. The yoke structure is formed by axially connecting the annular side portion 8b of the holder 8 and the yoke member 14, as shown in Figures 1, 3, and 5.

[0064] The holder 8 has first claw pole portions 8d that protrude to the right at regular intervals in the circumferential direction from the end of the annular side portion 8b on the second bearing ring 5 side. The yoke member 14 has an annular portion 14a that faces the peripheral portion 8a of the holder 8 at a radial interval, a side peripheral portion 14b that extends radially from the right end of the annular portion 14a toward the second bearing ring 5, and a second claw pole portion 14c that extends to the left at regular intervals in the circumferential direction from the side peripheral portion 14b. The yoke member 14 is made of a magnetic material such as a seamless steel plate. The overall shape of the yoke member 14 is formed by press working.

[0065] The first claw pole portion 8d and the second claw pole portion 14c are arranged in opposite axial directions and alternately arranged in the circumferential direction. A circumferential air gap is formed between the first claw pole portion 8d and the second claw pole portion 14c that are adjacent in the circumferential direction. As shown in Figures 1 and 2, the first claw pole portion 8d and the second claw pole portion 14c face each other in the radial direction with an air gap between them and the magnets of the magnetic ring 10.

[0066] 1 and 5, the coil 11a is wound around a bobbin 11b and arranged circumferentially in a space surrounded by the end of the annular side portion 8b on the second bearing ring 5 side, the side peripheral portion 14b, the annular portion 14a, the first claw pole portion 8d, and the second claw pole portion 14c.

[0067] The magnetic flux emanating from the north pole of the magnetic ring 10 shown in FIGS. 1 and 2 travels from the first claw pole 8d (or the second claw pole 14c), which is a magnetic pole, to the end of the annular side portion 8b on the second bearing ring 5 side (or the side circumferential portion 14b), then travels around the coil 11a to the side circumferential portion 14b (or the end of the annular side portion 8b on the second bearing ring 5 side) via the annular portion 14a, then travels around the coil 11a to the adjacent second claw pole 14c (or the first claw pole 8d), and returns to the south pole of the magnetic ring 10. When the north and south poles of the magnetic ring 10 swap positions with the relative rotation of the first bearing ring 4 and the second bearing ring 5, the direction of the magnetic flux reverses. The alternating magnetic field thus generated generates an alternating voltage at both ends of the coil 11a, at the beginning and end of the winding. While a radial-type claw pole generator is shown as the generator 3, other types of generators are also possible.

[0068] Both ends of the coil 11a are connected to input terminals of a power supply circuit 9e on the substrate 9a shown in Figure 3. The power supplies for the sensors 9b, 9c and the wireless communication circuit 9d are each output terminals of the power supply circuit 9e. This bearing device is capable of performing detection and wireless communication using the circuit substrate 9 with the generator 3 as its power source, making it possible to make the sensor unit 2 wireless. An emergency battery may be mounted on the substrate 9a, or the sensor unit may be modified to be driven solely by the battery.

[0069] The peripheral portion 8a and annular side portion 8b of the holder 8 and the annular portion 14a of the yoke member 14 form an opening for accommodating the circuit board 9. This opening is closed by a cover 15, as shown in FIGS. 1 and 2. The cover 15 is fixed to the circuit board 9 without contacting it. The internal space between the cover 15 and the circuit board 9 is filled with air. The spaces between the cover 15 and the peripheral portion 8a and between the cover 15 and the annular portion 14a may be sealed with a sealant, respectively.

[0070] The cover 15 is made of resin that does not contain metal. Even if the holder 8 and the yoke member 14 are made of metal, the cover 15 is radio wave transparent, so wireless communication using the antenna of the wireless communication circuit 9d is possible. The cover may be made of metal, with a portion of the area facing the antenna made of non-metal (for example, resin). It is also possible to seal the circuit board without using a cover by filling the opening with a sealant.

[0071] In the ring-shaped space radially sandwiched between the first raceway ring 4 and the second raceway ring 5, the circuit board 9, stator 11, and magnetic ring 10 are arranged so as to face each other radially and not overlap in the axial direction, and therefore these can be arranged thinly in the axial direction and provided as a bearing device of the same size as the rolling bearing 1 configured as a standard bearing.

[0072] This bearing device is as described above (see Figures 1 to 4), and comprises a rolling bearing 1 having a first raceway 4, a second raceway 5, and a plurality of rolling elements 6 arranged between the first raceway 4 and the second raceway 5, and a holder 8 connected to the first raceway 4 and capable of mounting a substrate 9a, sensors 9b, 9c, circuits 9d, 9e, etc., wherein the first raceway 4 has a fitting portion 4c that supports the holder 8 radially and a step portion 4d that supports the holder 8 axially.

[0073] This bearing device further includes at least one permanent magnet 12 arranged between the holder 8 and the first raceway 4 so as to fix the holder 8 to the first raceway 4 by magnetic attraction. This allows for a looser radial fit between the mating portion 4c of the first raceway 4 and the holder 8 compared to when the holder is fixed to the first raceway by relying solely on press-fitting, thereby reducing deformation of the first raceway 4 and the holder 8 when fixing the holder 8 for sensors 9b, 9c, etc. to the first raceway 4 and allowing the holder 8 to be easily reused.

[0074] Furthermore, in this bearing device, the fitting portion 4c of the first raceway 4 and the holder 8 are loosely fitted, and at least one permanent magnet 12 is arranged to secure the holder 8 to the first raceway 4 by axial magnetic attraction, eliminating concerns about deformation of the first raceway 4 and the holder 8 when the sensor unit 2 is secured. This allows the holder 8 to be secured to the first raceway 4 by axial magnetic attraction without being affected by the radial clearance. For example, if a permanent magnet that is magnetically attracted in the radial direction is placed between the fitting portion of the holder and the first raceway 4, the clearance that occurs between the fitting portion of the holder and the first raceway 4 becomes a magnetic gap between the permanent magnet and the holder, reducing the magnetic attraction force. However, if the magnetic attraction is in the axial direction, the clearance does not become a magnetic gap, and the holder 8 can be firmly attracted to the step 4d.

[0075] Furthermore, in this bearing device, since the first raceway 4 and the holder 8 are each made of a magnetic material, the first raceway 4 and the holder 8 are used to guide the magnetic flux of the permanent magnet 12, thereby increasing the magnetic flux circulating between the permanent magnet 12, the first raceway 4, and the holder 8, thereby making it possible to obtain a strong magnetic attraction force as described above.

[0076] Furthermore, this bearing device includes a recessed portion 4f that is recessed axially relative to the step portion 4d so that the first raceway 4 can embed the permanent magnet 12. This allows the permanent magnet 12 to be embedded in the recessed portion 4f so that it does not get in the way when the step portion 4d of the first raceway 4 supports the holder 8 in the axial direction. The permanent magnet 12 is sandwiched axially between the first raceway 4 and the holder 8 to create a closed magnetic circuit with the permanent magnet 12, holder 8, and first raceway 4, thereby achieving the aforementioned strong magnetic attraction force.

[0077] In addition, in this bearing device, the holder 8 has a peripheral portion 8a that fits into the mating portion 4c and a protrusion 8c that protrudes radially from the peripheral portion 8a, and the first raceway 4 has a notch portion 4e that forms an axial gap g between it and the protrusion 8c and fits snugly with the protrusion 8c in the circumferential direction.As a result, rotation of the holder 8 relative to the first raceway 4 can be prevented without rattling by the circumferential engagement of the notch portion 4e and the protrusion 8c, and when removing the holder 8 from the first raceway 4, a tool can be inserted into the axial gap g to apply an external force to the protrusion 8c, making it possible to easily separate the holder 8 from the first raceway 4.

[0078] A second embodiment of the present invention is shown in Fig. 6. In the following, only the differences from the first embodiment will be described.

[0079] The bearing device according to the second embodiment includes pairs of permanent magnets 12a, 12b that are adjacent to each other in the circumferential direction and arranged with opposite polarities. The two paired permanent magnets 12a, 12b are embedded in separate recesses in the first bearing ring 4. Of the two paired permanent magnets 12a, 12b, one permanent magnet 12a is arranged with its north pole facing the holder 8 (see also FIG. 1; the same applies below) in the axial direction and its south pole facing the first bearing ring 4 in the axial direction. In contrast, the other permanent magnet 12b, which is different from the one permanent magnet 12a, is arranged with its south pole facing the holder 8 in the axial direction and its north pole facing the first bearing ring 4 in the axial direction. A total of four pairs of permanent magnets 12a, 12b are fixed to the first bearing ring 4 with a circumferential gap between each pair. A series of magnetic paths are generated in which the magnetic flux emitted from the N pole of one permanent magnet 12a passes through the magnetic holder 8 and enters the S pole of the adjacent permanent magnet 12b, and the magnetic flux emitted from the N pole of the other permanent magnet 12b passes through the magnetic first bearing ring 4 and enters the S pole of the adjacent permanent magnet 12a. Therefore, the magnetic attractive force that the pair of permanent magnets 12a, 12b exerts on the holder 8 to the first bearing ring 4 is stronger than the magnetic attractive force exerted by the single permanent magnet 12 in the first embodiment.

[0080] In this way, the bearing device of the second embodiment is provided with a pair of permanent magnets 12a, 12b that are adjacent to each other in the circumferential direction and arranged with opposite polarities, thereby generating a magnetic field circulating between the opposite poles of the permanent magnets 12a, 12b that make up the pair, thereby obtaining a strong magnetic attraction force that attracts the holder 8 to the first raceway 4.

[0081] A third embodiment of the present invention is shown in FIGS.

[0082] The bearing device according to the third embodiment differs from the first embodiment in that the permanent magnets are fixed to the holder. Specifically, recesses 8e are added at multiple circumferentially spaced locations on the left side surface of the annular side portion 8b of the holder 8. A permanent magnet 16 is embedded in each recess 8e. The leftmost pole face of each permanent magnet 16 contacts the step portion 4d of the first bearing ring 4. Thus, the holder 8 is fixed to the first bearing ring 4 by the magnetic attraction force of at least one permanent magnet 16 disposed between the holder 8 and the first bearing ring 4. While the recesses 8e are formed in the annular side portion 8b in a non-penetrating manner in the illustrated example, they may also penetrate the annular side portion 8b.

[0083] A fourth embodiment of the present invention is shown in FIG.

[0084] The fourth embodiment is similar to the third embodiment in that a pair of permanent magnets is arranged as in the second embodiment. That is, in the bearing device according to the fourth embodiment, a pair of permanent magnets 16a, 16b, which are adjacent to each other in the circumferential direction and arranged with opposite polarities, are fixed to the left side surface of the annular side portion 8b of the holder 8. The two paired permanent magnets 16a, 16b are embedded in separate recesses in the annular side portion 8b. Of the paired two permanent magnets 16a, 16b, one permanent magnet 16a is arranged so that its north pole faces the step portion 4d of the first bearing ring 4 in the axial direction (see also FIG. 7; the same applies below), and its south pole faces the annular side portion 8b in the axial direction. In contrast, the other permanent magnet 16b, which is different from the one permanent magnet 16a, is arranged so that its south pole faces the step portion 4d of the first bearing ring 4 in the axial direction, and its north pole faces the annular side portion 8b in the axial direction. A total of four pairs of permanent magnets 16a, 16b are fixed to the annular side portion 8b with a circumferential gap between each pair. A series of magnetic paths are generated: magnetic flux from the N pole of one permanent magnet 16a passes through the first bearing ring 4 made of a magnetic material and enters the S pole of the adjacent permanent magnet 16b, and magnetic flux from the N pole of the other permanent magnet 16b passes through the annular side portion 8b made of a magnetic material and enters the S pole of the adjacent permanent magnet 16a. Therefore, the magnetic attractive force by which the pair of permanent magnets 16a, 16b attracts the holder 8 to the first bearing ring 4 is stronger than the magnetic attractive force of the single permanent magnet 16 in the third embodiment.

[0085] A fifth embodiment of the present invention is shown in FIG.

[0086] The bearing device according to the fifth embodiment is a combination of the first and third embodiments. That is, the bearing device according to the fifth embodiment includes a permanent magnet 12 fixed to the first bearing ring 4 and a permanent magnet 16 fixed to the holder 8.

[0087] The permanent magnet 12 on the first bearing ring 4 side and the permanent magnet 16 on the holder 8 side have opposite poles facing each other. In other words, of the magnetic pole at the right end of the permanent magnet 12 and the magnetic pole at the left end of the permanent magnet 16 facing it in the axial direction, one magnetic pole is a north pole and the other magnetic pole is a south pole. This opposite pole facing arrangement is established between all of the permanent magnets 12 and permanent magnets 16 facing each other in the axial direction.

[0088] Since the magnetic pole at the right end of permanent magnet 12 and the magnetic pole at the left end of permanent magnet 16 magnetically attract each other, the magnetic attraction force by which axially facing permanent magnets 12 and 16 attract holder 8 to first bearing ring 4 is stronger than the magnetic attraction force by a single permanent magnet 12 in the first embodiment.

[0089] In this way, in the bearing device of the fifth embodiment, the permanent magnet 12 fixed to the first raceway 4 and the permanent magnet 16 fixed to the holder 8 are arranged so that their opposite poles face each other, so that the permanent magnet 12 on the first raceway 4 side and the permanent magnet 16 on the holder 8 side attract each other, and therefore the permanent magnets 12 and 16 facing each other in the axial direction can obtain a strong magnetic attraction force that attracts the holder 8 to the first raceway 4.

[0090] In the fifth embodiment, a pair of permanent magnets is fixed to the first raceway ring as in the second embodiment, and a pair of permanent magnets is also fixed to the holder as in the fourth embodiment, and it is possible to change the configuration so that one permanent magnet on the first raceway ring side and one permanent magnet on the holder side have opposite poles facing each other, and the other permanent magnet on the first raceway ring side and the other permanent magnet on the holder side have opposite poles facing each other.

[0091] Furthermore, the phase of the first bearing ring and the holder in the circumferential direction may be aligned by a knock pin provided at least at one location on the surface of the first bearing ring and the holder on which the permanent magnet is arranged.

[0092] The first raceway ring can also be changed to an inner raceway ring, in which case a fitting portion, a step, or the like for fixing the sensor unit is formed on the outer periphery of the inner raceway.

[0093] If the holder is magnetic, it can be attracted directly by the magnetic force of a permanent magnet, but the holder body may be made of a non-magnetic material and a magnetic part may be provided on a part of the holder so that the magnetic part is attracted by magnetic force.Furthermore, the holder body may be made of a non-magnetic material and a magnetic member may be disposed on the opposite side of the holder from the permanent magnet, and this magnetic member may be attracted by magnetic force, thereby sandwiching the holder between the permanent magnet and the magnetic member and fixing the holder.

[0094] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0095] 1. Rolling bearings 2 Sensor Unit 3. Generator 4 First bearing ring 4c Mating part 4d step 4e Notch 4f, 8e recessed area 5 Second bearing ring 6 rolling elements 7 Cage 8 Holder 8a Periphery 8c protrusion 9 Circuit Board 9a board 9b, 9c Sensor 9d Wireless communication circuit 9e power circuit 10 Magnetic Ring 11 Stator 12, 12a, 12b, 16, 16a, 16b permanent magnet 14 Yoke member 15 Cover g Axial clearance

Claims

1. a rolling bearing having a first raceway, a second raceway, and a plurality of rolling elements disposed between the first raceway and the second raceway; a holder connected to the first bearing ring and capable of accommodating a substrate, a sensor, a circuit, etc.; In a bearing device, the first raceway has a fitting portion that supports the holder in a radial direction and a step portion that supports the holder in an axial direction, 10. A bearing device according to claim 9, further comprising at least one permanent magnet disposed between the holder and the first raceway ring so as to fix the holder to the first raceway ring by magnetic attraction.

2. the fitting portion of the first bearing ring and the holder are clearance-fitted, 2. The bearing assembly according to claim 1, wherein said at least one permanent magnet is positioned to secure said holder to said first race by axial magnetic attraction.

3. 3. The bearing device according to claim 1, wherein the first raceway ring and the holder are made of magnetic material.

4. 4. The bearing device according to claim 3, wherein at least one of said holder and said first bearing ring includes a recessed portion recessed in the axial direction relative to said step portion so that said permanent magnet can be embedded therein.

5. 5. A bearing device according to claim 3, further comprising a pair of the permanent magnets arranged adjacent to each other in the circumferential direction and with polarities opposite to each other.

6. the permanent magnet is fixed to the first bearing ring, and the permanent magnet is fixed to the holder; 5. The bearing device according to claim 1, wherein the permanent magnet fixed to the first raceway and the permanent magnet fixed to the holder are arranged with opposite poles facing each other.

7. the holder has a peripheral portion that fits into the fitting portion and a protrusion that protrudes radially from the peripheral portion, 5. The bearing device according to claim 1, wherein the first raceway ring has a notch that forms an axial gap between itself and the protrusion and that fits snugly around the circumferential surface of the protrusion.

Images