Bearing device

Abstract

To provide a bearing device capable of accurately detecting a temperature change of a bearing ring of a rolling bearing.SOLUTION: The bearing device includes a rolling bearing 1, and a sensor unit 2 fixed to a first bearing ring 4 of the rolling bearing 1, the first bearing ring 4 having an inner periphery 16 including a raceway surface part 15 and a peripheral face part 19 fitted to the sensor unit 2, the sensor unit 2 having a plurality of temperature sensors 10a-10c arranged at peripheral spaces from one another. The detection results of the temperature sensors 10a, 10b, 10c are monitored to detect the concurrent occurrence of a higher temperature of output in the first temperature sensor and a lower temperature of output in the second temperature sensor.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] For example, in the bearing device of Patent Document 1, a holder with an L-shaped cross section is attached to the raceway. The holder has an annular side portion extending in the radial direction and a fitting portion protruding in the axial direction from the raceway side of the annular side portion. The holder also serves as a yoke in the stator of the generator. The fitting portion of the holder is fitted to the circumferential surface portion of the raceway, and the protruding end face of the fitting portion is abutted against the step portion of the raceway in the axial direction. The circuit board is a control board including a plurality of sensors such as a temperature sensor. This circuit board is fixed on the side surface of the annular side portion on the rolling element side. The circumferential surface portion and the step portion of the raceway are formed between an end face located at one end that defines the width of the raceway and the raceway surface portion, and the sensor unit is arranged so as not to protrude from the raceway in the axial direction. The rolling bearing generates heat as the rolling bearing rotates. This heat occurs at the contact portion between the raceway surface portion and the rolling element. When the temperature sensor detects the temperature change based on the heat, it can be used as information indicating the condition of the bearing.

[0004] When the sensor unit is fitted to the inner or outer circumference including the raceway surface portion of the raceway ring, as in the bearing device of Patent Document 1, the difference between the temperature inside the rolling bearing and the temperature of the sensor unit can be reduced compared to when the sensor unit is fitted to the inner or outer circumference including the fitting surface portion of the raceway ring, which is advantageous for monitoring the condition of the rolling bearing based on the detection results of the temperature sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2003-307435 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the bearing device of Patent Document 1, although the control board of the sensor unit includes a temperature sensor, there is no particular mention of the arrangement of the temperature sensor or how to monitor the rolling bearing for abnormalities based on the detection result of the temperature sensor. For example, if the circumferential temperature distribution inside the rolling bearing is not known, it is difficult to know in detail what kind of abnormal heat has occurred in the rolling bearing. In addition, if the interference between the housing or shaft and the rolling bearing is insufficient due to a temperature rise or the like, a phenomenon may occur in which the outer ring fitted to the housing or the inner ring fitted to the shaft gradually rotates relative to the housing or shaft that is the mating mating member (hereinafter, this phenomenon is called creep). Creep wears the contact surface between the raceway and the mating mating member. If the wear of the contact surface progresses, a relative misalignment or tilt occurs between the shaft and the housing, causing abnormal noise and vibration.

[0007] In view of the above background, an object of the present invention is to provide a bearing device suitable for detecting various abnormalities in a rolling bearing. [Means for solving the problem]

[0008] 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 a plurality of rolling elements arranged between the first raceway and the second raceway, and a sensor unit fixed to the first raceway, wherein the first raceway has an inner or outer circumference including a raceway surface portion and a peripheral surface portion that fits with the sensor unit, the sensor unit has a plurality of temperature sensors, and the plurality of temperature sensors are arranged at intervals from each other in the circumferential direction.

[0009] As in the above configuration 1, when the sensor unit is fitted to the inner or outer circumference including the raceway surface of the first race and arranged near the raceway surface, the temperature inside the rolling bearing can reach the sensor unit quickly due to thermal conduction between the first race and the sensor unit. When the sensor unit detects with a plurality of temperature sensors arranged at intervals from each other in the circumferential direction, it becomes possible to detect the circumferential temperature distribution inside the rolling bearing. In addition, when creep occurs in the first race, the temperature distribution of the first race quickly follows the phase of the load zone of the rolling bearing, while the positions of the plurality of temperature sensors relative to the load zone and the temperature distribution change in the circumferential direction, so that the outputs of the plurality of temperature sensors distributed in the circumferential direction change simultaneously before and after creep. Therefore, it becomes possible to detect the occurrence of creep from the change in the output of the plurality of temperature sensors. In addition, although the temperature of the rolling bearing is affected by the environmental temperature (for example, the temperature of the surrounding machine body or the atmosphere), it becomes possible to use the difference in the output between the plurality of temperature sensors, so it becomes possible to detect a temperature rise caused by an abnormality in the rolling bearing without depending on the environmental temperature. Thus, according to the above configuration 1, it becomes possible to detect the circumferential temperature distribution inside the rolling bearing, and also makes it possible to detect the occurrence of creep in the first race in the case of an operating environment in which the temperature distribution corresponds to the load zone of the rolling bearing, making this a bearing device that is suitable for detecting various abnormalities in the rolling bearing.

[0010] In the above configuration 1, configuration 2 can be adopted in which the sensor unit has a circuit board including the multiple temperature sensors and a holder for holding the circuit board, the holder has an annular side portion extending radially and an engagement portion protruding axially from the annular side portion, the engagement portion being engaged with the peripheral surface portion of the first raceway, the inner or outer circumference including the raceway surface portion of the first raceway further includes a step portion that receives the side surface of the annular side portion facing the rolling body, and the circuit board is arranged on the side surface of the annular side portion facing the reversing moving body.

[0011] According to the above-mentioned configuration 2, the side surface of the annular side part of the holder facing the rolling elements is supported in the axial direction by a step part close to the raceway surface part of the first raceway, and a circuit board including multiple temperature sensors is disposed on the side surface of the annular side part facing the reversible moving elements, so that heat generated at the contact part between the raceway surface part and the rolling elements can be quickly transmitted to each temperature sensor on the circuit board through the same heat transfer path, thereby making it possible to quickly and accurately detect abnormal heat generation in the rolling bearing due to indentations or the like occurring on the raceway surface part of the first raceway.

[0012] In the above configuration 1 or 2, a configuration 3 can be adopted in which a creep determination unit is provided that monitors the detection results of each of the temperature sensors and detects the simultaneous occurrence of a rise in the output of the first temperature sensor and a fall in the output of the second temperature sensor.

[0013] In the radial load zone of the rolling bearing, the circumferential temperature distribution inside the rolling bearing due to the radial load corresponds to the circumferential distribution of the rolling element load. Therefore, when creep occurs in the first raceway, among the multiple temperature sensors that simultaneously displace in the creep direction, there is a first temperature sensor that approaches the maximum temperature position in the temperature distribution in the creep direction, while there is a second temperature sensor that moves away from the maximum temperature position in the temperature distribution in the creep direction. Therefore, the output of the first temperature sensor increases in temperature and the output of the second temperature sensor decreases in temperature at the same time. According to the above configuration 3, since a creep determination unit that detects the simultaneous occurrence of these increases in temperature and decreases in temperature is provided, creep of the first raceway can be detected.

[0014] In any one of the above configurations 1 to 3, a configuration 4 can be adopted in which a creep determination unit is provided that monitors which of the multiple temperature sensors has detected the highest temperature, and detects whether the highest temperature has been detected by a temperature sensor other than the temperature sensor that previously detected the highest temperature.

[0015] When the first race creeps, the temperature sensor closest to the maximum temperature position in the temperature distribution will be switched to another temperature sensor as the creep progresses. Therefore, if the temperature sensor that indicates the highest temperature at a certain time is different from the temperature sensor that detected the highest temperature before that time, this indicates that the temperature sensor closest to the maximum temperature position in the temperature distribution has been switched to another temperature sensor. Therefore, according to the above configuration 4, creep of the first race can be detected.

[0016] In any one of the above configurations 1 to 4, a configuration 5 can be adopted in which the sensor unit has a wireless communication circuit and a power source.

[0017] According to the above-mentioned configuration 5, the sensor unit does not require wired connections for communication and power supply, and the sensor unit can be made wireless, making it easy to incorporate the rolling bearing and sensor unit assembly into other machines. On the other hand, it becomes impossible to know the occurrence of creep due to a wire break caused by creep of the first raceway. If the sensor unit is made wireless and creep occurrence can be detected based on the output of multiple temperature sensors as described above, it becomes possible to detect creep at an early stage before wear progresses on the contact surface between the first raceway and its mating member.

[0018] In any one of the above configurations 1 to 5, a configuration 6 can be adopted in which an abnormal heat detection unit that determines a difference between outputs from the temperature sensors is provided.

[0019] According to the above configuration 6, abnormal heat generation in the rolling bearing can be detected independently of the environmental temperature.

[0020] In any one of the above configurations 1 to 6, a configuration 7 can be adopted in which the sensor unit includes a heat source detection unit that identifies the phase of the heat source based on the output of each temperature sensor, and the sensor unit has at least three temperature sensors as the multiple temperature sensors.

[0021] When a heat source such as an indentation occurs on the raceway surface of the first raceway ring, the output of a temperature sensor closer to the heat source becomes higher. When there are at least three temperature sensors distributed in the circumferential direction, the heat source is present in the section between the temperature sensor showing the highest temperature among the outputs of the temperature sensors and the temperature sensor showing the second highest temperature. Therefore, according to the above configuration 7, the phase of the heat source can be identified.

[0022] In any one of the above configurations 1 to 7, a configuration 8 can be adopted in which two of the plurality of temperature sensors are arranged at intervals of 180° in the circumferential direction.

[0023] In any one of the above configurations 1 to 8, a configuration 9 can be adopted in which the plurality of temperature sensors are disposed at equal intervals in the circumferential direction.

[0024] In any one of the above configurations 1 to 9, a configuration 10 can be adopted in which the plurality of temperature sensors are contained within a range of an axial width of the first bearing ring. Effect of the Invention

[0025] As described above, by employing configuration 1 above, the present invention can provide a bearing device suitable for detecting various abnormalities in a rolling bearing. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a side view showing a bearing device according to an embodiment of the present invention with a cover partially cut away; [Diagram 2] FIG. 2 is a longitudinal sectional front view showing a main part of the bearing device shown in FIG. [Diagram 3] An enlarged view of the sensor unit and its surroundings in Figure 2. [Figure 4] FIG. 2 is a perspective view showing the bearing device of FIG. [Diagram 5] FIG. 2 is an exploded perspective view of the stator of FIG. 1; [Figure 6]A schematic diagram showing the load zone, temperature distribution, and temperature sensor phase relationship of the rolling bearing in Figure 1. [Figure 7] Functional block diagram of the bearing device of FIG. 1 [Figure 8] A flow chart showing a creep monitoring process using the bearing device of FIG. [Figure 9] A flowchart showing the process of monitoring abnormal heat generation by the bearing device of FIG. 1. [Figure 10] FIG. 2 is a side view showing a modified example of the sensor unit of FIG. 1 in the same state as FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] A bearing device according to an embodiment as one example of the present invention (hereinafter simply referred to as "the bearing device") will be described with reference to the accompanying drawings, FIGS. 1 to 9. FIG.

[0028] As shown in FIGS. 1 and 2, the bearing device includes a rolling bearing 1, a sensor unit 2, and a generator 3.

[0029] Here, the circumferential direction centered on the bearing central axis O of the rolling bearing 1 is referred to as the "circumferential direction," the direction along the bearing central axis O is referred to as the "axial direction," and the direction perpendicular to the bearing central axis O is referred to as the "radial direction." The axial direction corresponds to the direction perpendicular to the page in Fig. 1, and corresponds to the left-right direction in Figs. 2 and 3. The radial direction corresponds to any linear direction extending along the page from the bearing central axis O in Fig. 1, and corresponds to the up-down direction in Figs. 2 and 3.

[0030] 1 and 2, 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.

[0031] The sensor unit 2 is a unit in which a circuit board 8 and a holder 9 for holding the circuit board 8 are integrated together.

[0032] The circuit board 8 has a plurality of temperature sensors 10a to 10c.

[0033] The holder 9 has an annular side portion 11 extending in the radial direction and a fitting portion 12 protruding from the annular side portion 11 in the axial direction.

[0034] The generator 3 consists of a magnetic ring 13 arranged so as to be rotatable integrally with the second raceway 5, and a stator 14 facing the magnetic ring 13, and the relative rotational motion between the first raceway 4 and the second raceway 5 is electromagnetically converted into alternating current by the magnetic ring 13 and the stator 14.

[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 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.

[0036] 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.

[0037] The sensor unit 2 is fixed to the first bearing ring 4 .

[0038] 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.

[0039] As shown in Figures 2 and 3, the first raceway ring 4 is an outer ring having an inner circumference 16 including a first raceway surface portion 15. The second raceway ring 5 is an inner ring having an outer circumference including a second raceway surface portion 17. Each rolling element 6 is a ball that rolls between the raceway surface portions 15, 17. The raceway surface portions 15, 17 are the surfaces of the raceways 4, 5 that form the rolling path of the rolling elements 6, and in the illustrated example, are continuous around the entire circumferential direction with a cross-sectional shape that forms a raceway groove corresponding to the ball diameter of the rolling elements 6.

[0040] A predetermined distance is ensured between the rolling elements 6, the cage 7, and the sensor unit 2. This distance is set so that the sensor unit 2 will not come into contact with the rolling elements 6 and the cage 7 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 Figure 2) with respect to each rolling element 6. To avoid interference between the sensor unit 2 and the cage 7, the cage 7 does not have a portion that is closer to the sensor unit 2 than the rolling elements 6. The sensor unit 2 does not have a portion that protrudes from the rolling bearing 1 in the axial direction.

[0041] The inner circumference 16 of the first race 4 includes a step portion 18 that axially receives the annular side portion 11 of the holder 9, and a peripheral surface portion 19 that fits with the fitting portion 12 of the holder 9. The step portion 18 extends radially all around the circumference. The peripheral surface portion 19 is a cylindrical surface that extends in the circumferential direction.

[0042] 2 to 4, the first raceway ring 4 has a width surface portion 20 located at one end of the axial width of the first raceway ring 4 (the right end in Figs. 2 and 3). The width surface portion 20 extends along the radial direction. The step portion 18 and the circumferential surface portion 19 are formed at a position closer to the first raceway surface portion 15 in the axial direction than the width surface portion 20 is.

[0043] As shown in FIGS. 2 and 3, the step portion 18 faces the first raceway surface portion 15 in the axial direction.

[0044] The peripheral surface portion 19 intersects with the step portion 18 at the other axial end of the peripheral surface portion 19 (the left end in Figs. 2 and 3).

[0045] In addition, the inner circumference 16 of the first raceway 4 may include at least one of a recessed portion between the step portion 18 and the circumferential surface portion 19 to facilitate processing, and a chamfered portion that removes the corners between the circumferential surface portion 19 and the width surface portion 20.

[0046] The holder 9 is an annular body that, when attached to the first bearing ring 4 , determines a predetermined position of the circuit board 8 relative to the first bearing ring 4 .

[0047] The entire holder 9 is formed from a single metal plate, and has a seamless, integral annular side portion 11 and a fitting portion 12. The entire holder 9 is formed by press working.

[0048] 1, the annular side portion 11 is in the form of an annular plate having both side surfaces 21, 22 extending along the radial direction over the entire circumference in the circumferential direction. The fitting portion 12 extends along the axial direction from the end of the annular side portion 11 closer to the first race 4.

[0049] 1 and 2, the fitting portion 12 is fitted to a peripheral surface portion 19 of the first bearing ring 4. As a result, the holder 9 is disposed coaxially with the first bearing ring 4.

[0050] 2 and 3, a side surface 21 of the annular side portion 11 on the rolling element 6 side (the side closer to the rolling element 6, the left side in Figs. 2 and 3) is butted against a step portion 18 of the first raceway 4 in the axial direction. As a result, the side surface 21 of the annular side portion 11 on the rolling element 6 side is in axial contact with the step portion 18. The step portion 18 appropriately determines the axial positional relationship between the fitted sensor unit 2 and the first raceway 4, and also restricts the sensor unit 2 from falling in the radial direction.

[0051] A side surface 22 on the reversible moving body 6 side (the side farther from the rolling body 6, the right side in Figs. 2 and 3) of the annular side portion 11 serves as a surface portion that supports the circuit board 8 in the axial direction.

[0052] 1 and 2, the circuit board 8 is a printed circuit board including a substrate 23, three temperature sensors 10a, 10b, and 10c mounted on the substrate 23, a wireless communication circuit 24 mounted on the substrate 23, a power supply circuit 25 mounted on the substrate 23, one or more other sensors 26 mounted on the substrate 23, and an information processing device 27 as a computer mounted on the substrate 23. The temperature sensors 10a, 10b, and 10c are arranged to fall within the axial width of the first bearing ring 4.

[0053] The substrate 23 is made of a printed wiring board. The substrate 23 is in the shape of an arc plate that is short in the radial direction and long in the circumferential direction. The substrate 23 is provided so as to extend longer than halfway around the circumference.

[0054] 2 and 3, both surfaces of the substrate 23 are oriented in the axial direction. The temperature sensors 10a to 10c, the wireless communication circuit 24, the power supply circuit 25, the one or more other sensors 26, and the information processing device 27 are each mounted on one surface of the substrate 23. This one surface of the substrate 23 is the surface on the side of the reversing body 6 of the substrate 23 (the right side in FIGS. 2 and 3).

[0055] The substrate 23 is in contact with the side surface 22 of the annular side portion 11 facing the reversible body 6 on the other side (the left side in Figs. 2 and 3) of the annular side portion 11 opposite to the aforementioned one side on which the temperature sensor 10a etc. are mounted. The contact portion between the side surface 22 of the annular side portion 11 facing the reversible body 6 and the substrate 23 is disposed at a position facing the first track surface portion 15 in the axial direction.

[0056] 1, the substrate 23 is fixed to the annular side portion 11 by a plurality of screws 28. As a result, the substrate 23 is fastened in the axial direction to the side surface 22 of the annular side portion 11 on the side of the reversible moving body 6, and is in contact with the side surface 22 without any gaps.

[0057] Each of the temperature sensors 10a, 10b, and 10c is made of a circuit that converts temperature into an electrical signal, and outputs a value indicating the detected temperature as a digital signal. Each of the temperature sensors 10a, 10b, and 10c is an electronic component with the same specifications, and there is no difference in temperature detection performance between them. Each of the temperature sensors 10a, 10b, and 10c is surface-mounted on the same side of the substrate 23.

[0058] The temperature sensors 10a, 10b, and 10c are arranged at intervals from one another in the circumferential direction and are arranged in a position axially facing the first raceway surface portion 15. The entire temperature sensors 10a, 10b, and 10c are located in a position radially facing the fitting portion 12 of the holder 9 and the peripheral surface portion 19 of the first raceway ring 4.

[0059] The three temperature sensors 10a to 10c are disposed at equal intervals in the circumferential direction and on the same circumference.

[0060] With respect to temperature sensor 10a located at one circumferential end of substrate 23, temperature sensor 10b located at the other circumferential end of substrate 23 is positioned at a position 180° (angle around the circumferential direction centered on bearing center axis O) opposite in the circumferential direction.

[0061] A heat conduction path is provided that continues in the axial direction from the first raceway surface portion 15 to each of the temperature sensors 10a, 10b, and 10c. The heat conduction path is preferably a solid portion that continues in the axial direction without gaps from the first raceway surface portion 15 to at least the circuit board 8, preferably to each of the temperature sensors 10a, 10b, and 10c. The axial heat conduction path between the first raceway surface portion 15 and the temperature sensor 10a, the axial heat conduction path between the first raceway surface portion 15 and the temperature sensor 10b, and the axial heat conduction path between the first raceway surface portion 15 and the temperature sensor 10c are preferably of the same structure. This is to make the thermal conductivity from the first raceway surface portion 15 to each of the temperature sensors 10a, 10b, and 10c the same, so that the temperature distribution in the circumferential direction of the first raceway ring 4 is reflected in the detection by the multiple temperature sensors 10a to 10c as quickly and accurately as possible. In the illustrated example, the heat conduction path between the first raceway surface portion 15 and each temperature sensor 10a, 10b, 10c is composed of a solid portion of the first raceway ring 4 that continues from the first raceway surface portion 15 to the step portion 18, the annular side portion 11 of the holder 9, and the substrate 23 of the circuit board 8, and is therefore substantially continuous in the axial direction with the same cross-sectional structure.

[0062] The rolling bearing 1 generates heat as it rotates. One of the main causes of this heat generation is frictional heat that occurs at the contact area between the rolling elements 6 and the first raceway ring 4. This frictional heat is transferred by heat conduction from the first raceway surface portion 15 through a short heat conduction path in the axial direction to each of the temperature sensors 10a, 10b, and 10c. Therefore, each of the temperature sensors 10a, 10b, and 10c can quickly and accurately detect temperature changes in the first raceway ring 4.

[0063] The technical significance of arranging the multiple temperature sensors 10a to 10c axially opposite the first raceway surface portion 15 is to shorten the path of heat conduction between the first raceway surface portion 15 and each of the temperature sensors 10a, 10b, and 10c in the axial direction in order to reduce delay and improve accuracy in temperature detection. Therefore, it is of course preferable to arrange each of the temperature sensors 10a, 10b, and 10c in its entirety axially opposite the first raceway surface portion 15, but it is considered effective in achieving the above-mentioned objective if at least the temperature-sensing portion (circuit portion that converts temperature into an analog electrical signal) of each of the temperature sensors 10a, 10b, and 10c is arranged axially opposite the first raceway surface portion 15.

[0064] Alternatively, multiple holes may be formed in the substrate in a pattern corresponding to the arrangement of multiple temperature sensors, the temperature sensors may be embedded in these holes, and each temperature sensor may be in contact with the side surface 22 of the annular side portion 11 facing the reversible body 6. Alternatively, holes may be formed axially penetrating the annular side portion in a pattern corresponding to the arrangement of multiple temperature sensors, and the temperature sensors may be mounted on one side of the substrate facing the rolling body so as to contact the step portion 18 through these holes. This makes it possible to shorten the heat conduction path in the axial direction between the first raceway surface portion 15 and each temperature sensor.

[0065] The one or more other sensors 26 are composed of a circuit that converts a physical quantity or a chemical quantity other than temperature into an electric signal. The type of the other sensor 26 is not particularly limited. For example, at least one of a group consisting of an acceleration sensor and an AE (Acoustic Emission) sensor is included in the one or more other sensors 26. When an acceleration sensor is employed, it is possible to detect radial or axial acceleration for monitoring vibration of the rolling bearing 1. When an AE sensor is employed, it is possible to detect an elastic wave (AE wave) emitted when sound generated when a part of an object such as a component of the rolling bearing 1 is deformed or broken or when an impact is applied. Note that electronic components including a temperature sensor and an acceleration sensor may be employed.

[0066] The wireless communication circuit 24 is composed of a communication circuit that converts predetermined information, such as the detection results by the multiple temperature sensors 10a to 10c, the detection results by one or more other sensors 26, and the calculation results by the information processing device 27, into radio waves and radiates them from the antenna 24a. The wireless communication circuit 24 complies with a predetermined communication protocol and is generally modular. To avoid a decrease in wireless communication performance, the antenna 24a of the wireless communication circuit 24 is not in contact with other members, such as a sealant.

[0067] The power supply circuit 25 is a circuit that converts the AC power generated by the stator 14 of the generator 3 into DC power used on the circuit board 8 .

[0068] As shown in Figs. 1 and 3, the magnetic ring 13 has a magnet 29 magnetized with alternating north and south poles in the circumferential direction, and a core metal 30. The magnet 29 is formed of magnetic rubber extending in the circumferential direction. The magnet 29 is bonded to the core metal 30 all around in the circumferential direction. Vulcanization bonding can be used as the bonding method. The core metal 30 has a flange portion for increasing its rigidity. Although the magnet 29 is exemplified as a magnetic material magnetized with multiple poles, it may be composed of a plurality of permanent magnets.

[0069] 2, the magnetic ring 13 is fixed to the stepped end 31 of the second raceway 5 so as not to protrude from the second raceway 5 in the axial direction. By fitting the magnetic ring 13 to the stepped end 31 of the second raceway 5, the second raceway 5 and the magnetic ring 13 are arranged coaxially. The stepped end 31 of the second raceway 5 is a portion for securing an annular space capable of accommodating the sensor unit 2 and the magnetic ring 13 between the circumferential surface portion 19 of the first raceway 4 and the second raceway 5, and has a shape that radially expands the space between the circumferential surface portion 19 and the end of the second raceway 5 that faces the stepped end 31 in the radial direction.

[0070] The stator 14 guides the magnetic flux emitted from the magnetic ring 13 through a yoke structure, and induces an AC voltage in the coil 32 within the yoke structure. The stator 14 is provided in the sensor unit 2. The stator 14 serves as a power source for the circuit board 8.

[0071] The yoke structure of the stator 14 is made up of a holder 9 and a yoke member 33 combined with annular side portion 11 of the holder 9, as shown in FIGS.

[0072] The holder 9 and the yoke member 33 are each made of a magnetic material such as a steel plate. The yoke member 33 is formed from a single metal plate. The overall shape of the yoke member 33 is formed by press molding.

[0073] The holder 9 has a first claw pole portion 34 which extends seamlessly and integrally from the side of the annular side portion 11 opposite the mating portion 12 (the side farther from the mating portion 12, the lower side in Figure 3) to the same side as the mating portion 12 (the right side in Figure 3) in the axial direction at regular intervals in the circumferential direction.

[0074] The yoke member 33 has, seamlessly and integrally, an annular plate portion 35 radially opposed to the fitting portion 12, a side plate portion 36 extending radially from the anti-annular side portion 11 side of the annular plate portion 35 (the side farther from the annular side portion 11, the lower side in Figure 3) to the anti-fitting portion 12 side (the side farther from the annular side portion 11, the right side in Figure 3), and a second claw pole portion 37 extending axially from the side plate portion 36 at a regular interval in the circumferential direction toward the annular side portion 11 side (the left side in Figure 3).

[0075] The yoke structure of the stator 14 is formed by a first claw pole portion 34, an annular side portion 11, an annular plate portion 35, a side plate portion 36, and a second claw pole portion 37. The fitting portion 12 of the holder 9 forms the outer periphery of the sensor unit 2. The first claw pole portion 34 and the second claw pole portion 37 are located on the inner periphery of the sensor unit 2.

[0076] As shown in Figs. 1 and 3, the first claw pole portion 34 and the second claw pole portion 37 face each other in the radial direction with an air gap between them and the magnet 29. The first claw pole portion 34 and the second claw pole portion 37 are arranged in opposite directions in the axial direction and are arranged alternately in the circumferential direction. A circumferential air gap is formed between the first claw pole portion 34 and the second claw pole portion 37 that are adjacent in the circumferential direction. The total number of the first claw pole portions 34 and the second claw pole portions 37 combined is equal to the number of poles of the magnet 29 (the total number of north poles and south poles).

[0077] 3 and 5, arc-shaped holes 38 axially penetrating the annular side portion 11 are formed at multiple locations in the circumferential direction. Protrusions 39 that fit into the inner surfaces of the holes 38 protrude in the axial direction from the annular plate portion 35. The annular plate portion 35 is abutted against the annular side portion 11 in the axial direction at substantially all portions except for the areas where these protrusions 39 are present.

[0078] The coil 32 is wound around a bobbin 40. The coil 32 and the bobbin 40 are arranged all around the circumference in a space surrounded by the annular side portion 11, the side plate portion 36, the annular plate portion 35, the first claw pole portion 34, and the second claw pole portion 37.

[0079] At least a portion of the surface of the coil 32 and the bobbin 40 may be in contact with the claw pole portions 34, 37, the annular side portion 11, and the side plate portion 36. When protecting the magnet wire constituting the coil 32 for the purposes of insulation, heat resistance, dust resistance, moisture resistance, and chafing prevention, a varnish treatment may be adopted in which the coil 32 is coated by dipping the coil 32 in varnish or by dripping varnish onto the coil 32. Also, the bobbin 40 may be omitted.

[0080] The magnetic flux emitted from the N pole of the magnet 29 shown in Fig. 1 and Fig. 3, for example, enters the annular side portion 11 (or side plate portion 36) from the first claw pole portion 34 (or the second claw pole portion 37), passes through the annular plate portion 35, goes around the coil 32 to the side plate portion 36 (or the annular side portion 11), and returns to the S pole of the magnet 29 via the adjacent second claw pole portion 37 (or the first claw pole portion 34). When the positions of the N pole and the S pole of the magnet 29 are interchanged with the rotation of the second race 5 relative to the first race 4, the direction of the magnetic flux is reversed. The alternating magnetic field generated in this way generates an AC voltage at both ends 41, 41 of the start and end of the winding of the coil 32.

[0081] Both ends 41, 41 of the coil 32 are connected to terminals 42, 42 provided on the substrate 23 through wiring holes formed slightly in the annular plate portion 35.

[0082] In assembling the sensor unit 2, as shown in FIG. 5, the bobbin 40 around which the coil 32 is wound is placed between the annular side portion 11 of the holder 9 and the side plate portion 36 of the yoke member 33, and the holder 9 and the yoke member 33 are assembled in the axial direction, and at this time, each protrusion 39 of the yoke member 33 is inserted into the corresponding hole 38 of the annular side portion 11. This insertion ensures that the holder 9 and the yoke member 33 are coaxial with each other, and the first claw pole portion 34 and the second claw pole portion 37 are alternately arranged in a predetermined phase with a gap in the circumferential direction. Therefore, the holder 9 and the yoke member 33 can be assembled appropriately without using a jig. It is preferable that the holes 38 and the protrusions 39 are each formed in three or more places.

[0083] After this assembly, the protrusion 39 is fixed to the inner surface of the hole 38. This fixing may be performed by, for example, press fitting, bonding, laser welding, or a combination of these.

[0084] It is also possible to omit the protrusions 39 and the holes 38. In this case, after the holder and the yoke member are coaxially aligned and phase-aligned using a jig (not shown), the butting portions of the annular side portion and the annular plate portion may be bonded or laser-welded from the outer periphery of the annular plate portion, or these may be fixed using a combination of these methods.

[0085] When holder 9 and yoke member 33 are fixed in the assembled state as described above, stator 14 is completed, having a cross-sectional structure as shown in Fig. 2. Note that, although an example has been shown in which annular plate portion 35 of yoke member 33 serves as a partition between the storage space for circuit board 8 and stator 14, it is also possible to provide a partition wall separate from the annular plate portion that divides the annular side portion of the holder into two regions in the radial direction, and to place the stator on the radial inside of that partition wall.

[0086] Next, the circuit board 8 is inserted onto the annular side portion 11, and the board 23 is fixed to the annular side portion 11 using a plurality of screws 28. At this time, the other surface of the board 23, which is opposite to the mounting surface of the temperature sensor 10a, etc., is made to face the annular side portion 11. Here, it is preferable that the other surface of the board 23 and the annular side portion 11 are in contact with each other in the axial direction, but in order to insulate the holder 9 from the circuit board 8, an insulating sheet such as a polyimide film may be interposed between the board 23 and the annular side portion 11, or the board 23 and the annular side portion 11 may be fixed to each other by adhesion using an adhesive, an adhesive sheet, etc., or by a combination of adhesion and screw fastening. It is preferable to use an adhesive, adhesive sheet, or insulating sheet with as good thermal conductivity as possible.

[0087] After the circuit board 8 is fixed to the annular side portion 11, an assembly process is performed in which the cover 43 is fitted between the fitting portion 12 and the annular plate portion 35 as shown in Figures 1, 3, and 4. As a result, the cover 43 closes the opening between the fitting portion 12 and the annular plate portion 35 without contacting the circuit board 8, and the gap between the cover 43 and the circuit board 8 becomes filled with air. Note that there is no particular limit to the means for fixing the cover 43, but in order to improve the airtightness of the fitting portions between the cover 43 and the fitting portion 12 and between the cover 43 and the annular plate portion 35, an adhesive or a resin filler may be applied to the fitting portions.

[0088] The cover 43 is made of resin that does not contain metal. Even if the holder 9 and the yoke member 33 are made of metal, the cover 43 has radio wave permeability, so wireless communication using the antenna 24a is possible. It is also possible to seal the circuit board 8 by filling the opening between the fitting portion 12 and the annular plate portion 35 with a sealant without using the cover 43. In this case, since the antenna 24a is covered with the sealant, it is advisable to use a sealant with a low relative dielectric constant, such as a resin, to suppress shortening of the wavelength of radio waves due to the dielectric constant of the sealant.

[0089] After the cover 43 is fixed, as shown in Figures 1 and 2, the sensor unit 2 is fixed to the peripheral surface portion 19 of the first raceway 4 at the fitting portion 12. Meanwhile, the magnetic ring 13 is fixed to the outer periphery of the second raceway 5. The fixing means for them is press-fitting, bonding, or a combination of these. Since the first raceway 4 and the second raceway 5 are arranged coaxially, the sensor unit 2 and the magnetic ring 13 are also arranged coaxially.

[0090] Since the variation in the radial gap between the magnetic ring 13 fixed to the second raceway 5, which is a component of the radial bearing, and the stator 14 of the sensor unit 2 fixed to the first raceway 4, which is also a component of the radial bearing, is small, a stable amount of power can be generated by the generator 3 composed of the magnetic ring 13 and the stator 14, compared to the case where a magnetic ring is provided on the cage. Since the detection, calculation processing, and wireless communication can be performed by the circuit board 8 using the stator 14 as a power source, the sensor unit 2 can be made wireless. Note that a storage battery may be mounted on the annular side portion 11 or the board 23 as an emergency power source. In addition, the power source for making it wireless is not limited to the stator of the generator, and may be a storage battery that can be mounted on the sensor unit or a power receiving circuit of a wireless power supply device.

[0091] 2, the assembly of the rolling bearing 1 and sensor unit 2 is disposed between a shaft S, which is a component of a rotating machine, and a housing H that surrounds the shaft S. The first race 4 in the illustrated example consists of an outer ring, and is fitted into the housing H. On the other hand, the second race 5 consists of an inner ring, and is fitted into the shaft S. The rolling bearing 1 is a radial bearing, and is therefore able to support a static load in the radial direction acting between the shaft S and the housing H.

[0092] When a rolling bearing 1 (see FIG. 1, the same applies below) is used while supporting a static load in the radial direction, the load zone of the rolling bearing 1 and the circumferential temperature distribution inside the rolling bearing 1 are usually as shown in FIG. 6. Here, in FIG. 6, the horizontal axis indicates the circumferential phase, the vertical axis on the left indicates the rolling element load, and the vertical axis on the right indicates the temperature. In FIG. 6, the solid line (solid line in an approximately semicircular arc shape) indicates the magnitude of the radial load applied to the rolling elements 6 of the rolling bearing 1 shown in FIG. 1 and FIG. 2 at a certain circumferential position. The origin position of the horizontal axis at 0° is the circumferential position where the static load of the radial load results in the maximum rolling element load. In FIG. 6, the dashed line (almost cosine wave dashed line in an approximately cosine wave shape) indicates the temperature inside the rolling bearing 1 at a certain circumferential position. In Fig. 6, arrows Pa, Pb, and Pc indicate the circumferential positions of temperature sensors 10a, 10b, and 10c (see Fig. 1, the same applies below) at a certain point in time in a rotating machine in which rolling bearing 1 is incorporated between a shaft S and a housing H. Arrow Pa corresponds to the circumferential position of temperature sensor 10a, arrow Pb corresponds to the circumferential position of temperature sensor 10b, and arrow Pc corresponds to the circumferential position of temperature sensor 10c.

[0093] The temperature inside the rolling bearing 1 rises due to the operation of the rotating machine in which the shaft S rotates in the circumferential direction relative to the housing H shown in FIG. 2. At this time, in the radial load range (approximately -90° to 90°) of the rolling bearing 1, a radial load is applied to the contact portion between the rolling element 6 (see FIG. 1; the same applies below) and the first raceway surface portion 15 (see FIG. 1; the same applies below) and frictional heat is generated. During the operation of the rotating machine, the first raceway ring 4 (see FIG. 1; the same applies below) may creep against the housing H due to some reason such as a decrease in the tightening margin with respect to the housing H as its mating partner. Even if the first raceway ring 4 creeps, the circumferential speed of the creep is slow. For this reason, the circumferential temperature distribution of the creeping first raceway ring 4 quickly settles based on the rolling element load distribution in the above-mentioned load range, and the circumferential temperature distribution inside the rolling bearing 1 also quickly settles to the distribution of the dashed line in FIG. 6. On the other hand, the multiple temperature sensors 10a-10c included in the circuit board 8 are fixed to the first race 4 via the holder 9 of the sensor unit 2, and therefore rotate together with the creeping first race 4. Therefore, if the creep direction of the first race 4 from the time of FIG. 6 is clockwise in FIG. 1, the circumferential positions Pa-Pc of the multiple temperature sensors 10a-10 will displace at the same speed and by the same distance from the positions depicted in FIG. 6 (displaced to the right in FIG. 6) in unison with respect to the temperature distribution in FIG. 6. Also, if the creep direction of the first race 4 from the time of FIG. 6 is counterclockwise in FIG. 1, the circumferential positions Pa-Pc of the multiple temperature sensors 10a-10 will displace at the same speed and by the same distance from the positions depicted in FIG. 6 (displaced to the left in FIG. 6) in unison with respect to the temperature distribution in FIG. 6.

[0094] For example, in the range where clockwise creep progresses from the point in Figure 6 to 90°, the circumferential position Pa of temperature sensor 10a approaches the maximum temperature position (phase 0° above) in the temperature distribution in the creep direction (rightward in Figure 6) from phase -90° above, so that the output of temperature sensor 10a becomes hotter (the output changes to a value indicating a higher temperature), and the circumferential position Pb of temperature sensor 10b moves away from the maximum temperature position (phase 0° above) in the temperature distribution from phase 90° above to 180° above, and also the circumferential position Pc of temperature sensor 10c moves away from the maximum temperature position (phase 0° above) in the temperature distribution from phase 0° above to 90° above, so that the outputs of temperature sensors 10b and 10c each become colder (the output changes to a value indicating a lower temperature). Furthermore, in the range in which the counterclockwise creep progresses from the point in Figure 6 to 90°, the circumferential position Pa of temperature sensor 10a moves from phase -90° above to phase -180° above in the creep direction (leftward in Figure 6) relative to the maximum temperature position in the temperature distribution (phase 0° above), and the circumferential position Pc of temperature sensor Pc moves from the maximum temperature position in the temperature distribution (phase 0° above) to phase -90° above, so that the outputs of temperature sensors 10a and 10c each decrease, while the circumferential position Pb of temperature sensor 10b moves from phase 90° above to approach the maximum temperature position in the temperature distribution (phase 0° above), so that the output of temperature sensor 10b becomes higher.

[0095] Furthermore, if an abnormality such as an indentation or peeling occurs in the radial load zone of the rolling bearing 1, friction with the rolling elements 6 will be strong at the location where the abnormality occurred, causing abnormal heat generation and becoming a heat source that disrupts the temperature distribution shown in Fig. 6. For this reason, even if the circumferential positions Pa to Pc of the multiple temperature sensors 10a, 10b, 10c do not change from the point in Fig. 6, the output of each of the temperature sensors 10a, 10b, 10c will change depending on the distance from the heat source, and the closer the temperature sensor 10a, 10b, 10c is to the heat source, the higher the output will be.

[0096] This bearing device is equipped with an information processing device 27 (see Figures 1 and 7; the same applies below) that performs calculations based on the relationship between the creep of the first raceway 4 and the occurrence of heat sources, as described above, and the changes in output of multiple temperature sensors 10a to 10c that are arranged at intervals in the circumferential direction.

[0097] The information processing device 27 is connected to each of the temperature sensors 10a, 10b, and 10c using a circuit pattern formed on the circuit board 8 as a transmission medium. The information processing device 27 and a controller C arranged outside the sensor unit 2 are wirelessly connected by wireless communication via a transmission processing unit 24b of the wireless communication circuit 24.

[0098] The information processing device 27 is configured from the hardware and software resources of a microcomputer device mounted on the substrate 23, and has the functions shown in FIG.

[0099] That is, the information processing device 27 has a data recording unit 27a that holds all data used for calculation processing in the information processing device 27, a creep judgment unit 27b that detects creep of the first race 4 based on the detection results of the multiple temperature sensors 10a-10c, an abnormal heat detection unit 27c that detects abnormal heat generation in the rolling bearing 1 based on the output of the multiple temperature sensors 10a-10c, and a heat source detection unit 27d that detects the phase of the heat source of the rolling bearing 1 based on the output of the multiple temperature sensors 10a-10c (hereinafter, for these functional units, please refer to Figure 7 as appropriate).

[0100] The data recording unit 27a manages the writing, erasing, updating, etc. of sensor identification data for identifying each of the temperature sensors 10a, 10b, 10c, required temperature data obtained from the output of each of the temperature sensors 10a, 10b, 10c, threshold data used in arithmetic processing, etc. The threshold is recorded in advance in the data recording unit 27a. This recording can be performed, for example, by transmitting a recording command including the threshold from the controller C.

[0101] The creep determination unit 27b monitors the detection results of each temperature sensor 10a, 10b, 10c, and detects the simultaneous occurrence of a rise in the output of a first temperature sensor among the multiple temperature sensors 10a to 10c and a fall in the output of a second temperature sensor other than the first temperature sensor among the multiple temperature sensors 10a to 10c.

[0102] Specifically, as shown in FIG. 8, the creep determination unit 27b periodically acquires the outputs of the temperature sensors 10a, 10b, and 10c to perform a process of monitoring the detection results of the temperature sensors 10a, 10b, and 10c (step S1).

[0103] In addition, the creep determination unit 27b identifies the temperature sensor 10x (x is any one of a to c) that shows the highest temperature (highest value) among the temperature sensors 10a, 10b, and 10c acquired in step S1, and performs a process of recording this in the data recording unit 27a (step S2).

[0104] In addition, the creep determination unit 27b performs a process of comparing the temperature sensor 10x indicating the highest value identified in step S2 with the temperature sensor 10x recorded in the data recording unit 27a in the previous step S2 to determine whether it is the same (step S3).

[0105] In step S3, if the creep determination unit 27b confirms that the temperature sensor 10x showing the highest value this time matches the temperature sensor 10x recorded in the previous step S3, or if the data recording unit 27a does not have a record of the previous temperature sensor 10x, the process returns to step S1. If the temperature sensor 10x this time is the same as the temperature sensor 10x recorded in the previous time, creep has not occurred in the first race 4. Also, when the rotating machine is just starting to operate, the first cycle of monitoring is already started, and the previous temperature sensor 10x to be compared has not been recorded in the first place. In such a case, the process returns to step S1, and the temperature sensor 10x recorded in the first cycle (previous time) can be compared for identity at the next second cycle of monitoring.

[0106] On the other hand, when creep determination unit 27b confirms in step S3 that there is a mismatch between the temperature sensor 10x showing the highest value this time and the temperature sensor 10x recorded in the previous step S3, it records the occurrence of this mismatch in data recording unit 27a. The mismatch here is due to the fact that the output of temperature sensor 10x (corresponding to the aforementioned first temperature sensor) showing the highest temperature this time among the multiple temperature sensors 10a to 10c (corresponding to the aforementioned second temperature sensor) has become higher, and the output of the other temperature sensor 10x recorded in the previous step S3 (corresponding to the aforementioned second temperature sensor) has become lower, so that the simultaneous occurrence of these, that is, the occurrence of creep in the first race 4, has been detected.

[0107] The calculation process performed by the creep determination unit 27b to detect creep of the first race 4 is not limited to the example shown in FIG. 8, and may be any process that detects the simultaneous occurrence of a rise in the output of the first temperature sensor and a fall in the output of the second temperature sensor among the plurality of temperature sensors 10a to 10c. For example, it is possible to calculate the temperature change amount of each of the temperature sensors 10a, 10b, and 10c, record the calculated value in the data recording unit 27a, and determine whether or not the temperature change amount of each of the temperature sensors 10a, 10b, and 10c exceeds a threshold value previously recorded in the data recording unit 27a. The fact that the temperature change amount exceeds the threshold value corresponds to the circumferential displacement of each of the temperature sensors 10a, 10b, and 10c with respect to the load zone of the rolling bearing 1. In this case, it is necessary to calculate and record the amount of temperature change of each temperature sensor 10a, 10b, 10c for each period and compare it with a threshold value, whereas the process of monitoring which temperature sensor 10x is detecting the highest temperature and determining whether to switch to the temperature sensor 10x that shows the highest temperature compared to the previous time, as in the example of Figure 8, requires fewer calculations, records, etc., and can reduce the power consumption of the information processing device 27 required for creep detection.

[0108] As shown in FIG. 9, the abnormal heat detection unit 27c performs a process of periodically acquiring the outputs of the temperature sensors 10a, 10b, and 10c to monitor the detection results of the temperature sensors 10a, 10b, and 10c (step S11).

[0109] The abnormal heat detection unit 27c calculates the difference between the highest temperature (maximum value) and the lowest temperature (minimum value) among the outputs of the temperature sensors 10a, 10b, 10c acquired in step S11 (step S12). This obtains a difference that subtracts from the maximum value the influence of the environmental temperature around the rolling bearing 1 on the entire rolling bearing 1. Thereafter, the abnormal heat detection unit 27c proceeds to a predetermined calculation process based on the difference obtained here, and ends the processing for that period. Here, the predetermined calculation process may be a process that detects abnormal heat generation in the rolling bearing 1 based on the value of the difference, and may, for example, detect abnormal heat generation by comparing the difference with a predetermined threshold value recorded in the data recording unit 27a.

[0110] Furthermore, when the abnormal heat detection unit 27c acquires the outputs of the temperature sensors 10a, 10b, and 10c in step S11, it passes these acquired output values ​​to the heat source detection unit 27d to check the phase of the heat source (step S13).

[0111] After step S13, the heat source detection unit 27d performs a predetermined comparison calculation process to identify the phase of the heat source based on the output of each of the temperature sensors 10a, 10b, and 10c acquired in step S13. Here, the predetermined comparison calculation process may, for example, compare the outputs of the at least three temperature sensors 10a, 10b, and 10c acquired in step S13 with each other, identify the temperature sensor showing the highest temperature (maximum value) among these at least three outputs and the temperature sensor showing the next highest temperature after this maximum temperature, and determine the interval between these two temperature sensors as the phase of the heat source.

[0112] In the example of Figure 8, it is assumed that the creep determination unit 27b and the abnormal heat detection unit 27c are asynchronous, and an example is shown in which the abnormal heat detection unit 27c independently executes step S11. However, if the abnormal heat detection unit 27c and the creep determination unit 27b are synchronous, step S11 in Figure 8 may be omitted, and the output values ​​of each of the temperature sensors 10a, 10b, and 10c acquired in step S1 in Figure 7 may be used for processing in the abnormal heat detection unit 27c and the heat source detection unit 27d.

[0113] Furthermore, the respective detection results of the creep determination unit 27b, the abnormal heat detection unit 27c, and the heat source detection unit 27d may be recorded in the data recording unit 27a, or instead of or in addition to the recording, the transmission processing unit 24b of the wireless communication circuit 24 may be instructed to transmit the detection results to a predetermined destination, for example, the controller C. Furthermore, when recording or transmitting the detection results, related information accompanying the detection results, for example, the date and time of occurrence of creep or abnormal heat, the maximum temperature, etc., may be included.

[0114] Also, in this bearing device, an example has been shown in which the information processing device 27, which is a computer for detecting creep of the first race 4, the temperature distribution of the rolling bearing 1, and abnormal heat generation, is mounted on the sensor unit 2, but all or part of the functions of this computer may not be mounted on the sensor unit, but may be mounted on one or more external computers connected to the sensor unit wirelessly or by wire, for example, on the controller C in Fig. 7 and / or the control computer of the rotating machine equipped with the shaft S and housing H in Fig. 2. When not all the functions of the information processing device 27 are mounted on the sensor unit but rely on an external computer, the sensor unit simply transmits the outputs of the multiple temperature sensors 10a-10c to the external computer.

[0115] In other words, in this invention, the rolling bearings and sensor unit of the bearing device must be configured as a structurally continuous assembly, while the calculation processing based on the outputs of the multiple temperature sensors may be performed by at least one of a computer that is structurally continuous with the assembly and a computer that is not structurally continuous with the assembly, and when communication is performed between a structurally discontinuous computer and the sensor unit, the communication does not have to be performed only through the wireless communication circuit of the sensor unit, but may be performed through an appropriate computer network via a local network, mobile communication network, the Internet, etc. from the wireless communication circuit, allowing the rolling bearings to be monitored remotely.

[0116] Furthermore, in this bearing device, an example has been shown in which temperature sensors 10a, 10b, and 10c are distributed at three points around the circumference as shown in Figure 1, but it is sufficient to use at least two temperature sensors so that a temperature sensor whose output becomes higher during creep and a temperature sensor whose output becomes lower are generated simultaneously. For example, it is also possible to mount only two temperature sensors, temperature sensor 10a and temperature sensor 10b, arranged 180° apart around the circumference, on circuit board 8 as shown in Figure 10.

[0117] This bearing device is as described above 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 sensor unit 2 fixed to the first raceway 4.

[0118] In particular, in this bearing device (see Figs. 1 and 2), the first raceway ring 4 has an inner circumference 16 including a first raceway surface portion 15 (raceway surface portion) and a peripheral surface portion 19 that fits with the sensor unit 2, so that the temperature distribution inside the rolling bearing 1 can reach the sensor unit 2 quickly by thermal conduction between the first raceway ring 4 and the sensor unit 2. The sensor unit 2 has a plurality of temperature sensors 10a to 10c, and the plurality of temperature sensors 10a to 10c are arranged at intervals in the circumferential direction, so that it is possible to detect the circumferential temperature distribution inside the rolling bearing 1. When creep occurs in the first raceway ring 4, the temperature distribution of the first raceway ring 4 quickly follows the phase of the load zone of the rolling bearing 1, while the positions of the plurality of temperature sensors 10a to 10c relative to the load zone and the position of the temperature distribution change in the circumferential direction, so that the outputs of the plurality of temperature sensors 10a to 10c distributed in the circumferential direction change simultaneously before and after creep of the first raceway ring 4. Therefore, it becomes possible to detect the occurrence of creep in the first race 4 from changes in the outputs of the plurality of temperature sensors 10a-10c. Also, although the temperature of the rolling bearing 1 is affected by environmental temperatures such as the temperature of the surrounding mechanical body and the atmospheric temperature, it becomes possible to use the difference in the outputs of the plurality of temperature sensors 10a-10c, so it becomes possible to detect a temperature rise caused by an abnormality in the rolling bearing 1 without depending on the environmental temperature.

[0119] In this way, this bearing device makes it possible to detect the circumferential temperature distribution inside the rolling bearing 1, and also makes it possible to detect the occurrence of creep in the first race 4 in the case of an operating environment in which the temperature distribution corresponds to the load zone of the rolling bearing 1, and therefore can be provided as a device that is suitable for detecting various abnormalities in the rolling bearing 1.

[0120] In addition, in this bearing device, the sensor unit 2 has a circuit board 8 including a plurality of temperature sensors 10a-10c, and a holder 9 that holds the circuit board 8, the holder 9 has an annular side portion 11 extending radially, and a fitting portion 12 protruding in the axial direction from the annular side portion 11, the fitting portion 12 is fitted into a peripheral surface portion 19 of the first raceway 4, the inner circumference 16 including the raceway surface portion 15 of the first raceway 4 further includes a step portion 18 that receives a side surface 21 of the annular side portion 11 on the rolling element 6 side, and the circuit board 8 is disposed on a side surface 22 of the annular side portion 11 on the reversible moving element 6 side, thereby Since the side surface 21 of the annular side portion 11 of the roller 9 facing the rolling element 6 is axially supported by a step portion 18 close to the raceway surface portion 15 of the first raceway ring 4, and a circuit board 8 including multiple temperature sensors 10a-10c is arranged on the side surface 22 of the annular side portion 11 facing the reversible moving element 6, heat generated at the contact portion between the raceway surface portion 15 and the rolling element 6 can quickly reach each of the temperature sensors 10a-10c on the circuit board 8 via a similar heat transfer path, and thus abnormal heating of the rolling bearing 1 due to indentations or the like occurring on the raceway surface portion 15 of the first raceway ring 4 can be quickly and accurately detected.

[0121] This bearing device also includes a creep determination unit 27b that monitors the detection results of each of the temperature sensors 10a, 10b, 10c and detects the simultaneous occurrence of a rise in the output of a first temperature sensor (at least one of 10a to 10c) and a fall in the output of a second temperature sensor (at least one other than the first temperature sensor among 10a to 10c), so that creep of the first raceway 4 can be detected by the creep determination unit 27b under usage conditions in which the circumferential temperature distribution inside the bearing corresponds to the circumferential distribution of the rolling element load in the radial load zone of the rolling bearing 1. In other words, when creep occurs in the first raceway 4, among the multiple temperature sensors 10a to 10c that simultaneously displace in the creep direction, some first temperature sensors move in the creep direction toward the maximum temperature position in the temperature distribution, while some second temperature sensors move away in the creep direction from the maximum temperature position in the temperature distribution. Therefore, whether or not the output of the first temperature sensor increases and the output of the second temperature sensor decreases simultaneously indicates whether or not creep of the first bearing ring 4 occurs.

[0122] In addition, this bearing device (see Figs. 6 to 8) includes a creep determination unit 27b that monitors which of the multiple temperature sensors 10a to 10c detects the highest temperature and detects whether the highest temperature is detected by a temperature sensor 10x other than the temperature sensor that previously detected the highest temperature. Therefore, creep of the first race 4 can be detected by the creep determination unit 27b under conditions in which the circumferential temperature distribution inside the bearing corresponds to the circumferential distribution of the rolling body load in the radial load zone of the rolling bearing 1. That is, when creep occurs in the first race 4, the temperature sensor closest to the maximum temperature position in the temperature distribution is switched to another temperature sensor as the creep progresses. Therefore, the fact that the temperature sensor 10x that shows the highest temperature at a certain time is different from the temperature sensor that detected the highest temperature before this time indicates that the temperature sensor closest to the maximum temperature position in the temperature distribution has been switched to another temperature sensor 10x due to the simultaneous occurrence of a high temperature output from the first temperature sensor and a low temperature output from the second temperature sensor due to creep in the first race 4.

[0123] In addition, in this bearing device (see Figures 1 and 2), since the sensor unit 2 has a wireless communication circuit 24 and a stator 14 as a power source, the sensor unit 2 does not require a wired connection for communication and power supply, making the sensor unit 2 wireless. This makes it easier to incorporate the assembly of the rolling bearing 1 and sensor unit 2 into other machines. Although the occurrence of creep cannot be detected by a wire break caused by creep of the first raceway 4, as in the case of a wired connection, the occurrence of creep can be detected based on the outputs of the multiple temperature sensors 10a to 10c, as described above. Therefore, it is possible to detect creep at an early stage before wear progresses on the contact surface between the first raceway 4 and its mating housing H.

[0124] In addition, this bearing device (see Figures 6, 7 and 9) is equipped with an abnormal heat detection unit 27c that determines the difference between the outputs of each temperature sensor 10a, 10b, 10c, making it possible to detect abnormal heat generation in the rolling bearing 1 independent of the environmental temperature.

[0125] In addition, this bearing device is equipped with a heat source detection unit 27d that identifies the phase of the heat source based on the output of each temperature sensor 10a, 10b, 10c. Since the sensor unit 2 has at least three temperature sensors 10a, 10b, 10c as the multiple temperature sensors 10a to 10c, it is possible to identify the phase of the heat source in the section between the temperature sensor that shows the highest temperature among the outputs of the at least three temperature sensors 10a, 10b, 10c distributed in the circumferential direction and the temperature sensor that shows the next highest temperature after this highest temperature.

[0126] In addition, in this bearing device, two of the multiple temperature sensors 10a, 10b are arranged circumferentially at intervals of 180°, thereby maximizing the circumferential distance between the two temperature sensors 10a, 10b, making it easier to detect the circumferential temperature distribution caused by abnormal heat generation in the rolling bearing 1.Furthermore, since the load zone of the radial load of the rolling bearing 1 is distributed over approximately 180°, when creep occurs in the first raceway 4, the output of one of the temperature sensors 10a or 10b will become higher depending on the direction of creep, and conversely, the output of the other temperature sensor 10b or 10a will become lower, making it possible to make a creep judgment based on both of these outputs.

[0127] Furthermore, in this bearing device, since the multiple temperature sensors 10a-10c are arranged at equal intervals in the circumferential direction, when the first raceway 4 creeps, the output changes of the multiple temperature sensors 10a-10c become periodic, so that the same calculation processing can be applied to each sensor output, thereby avoiding the need for complicated calculation processing.

[0128] In this bearing device, an example has been shown in which three temperature sensors 10a, 10b, 10c are equally spaced circumferentially at 90° intervals; however, it is sufficient to arrange at least two temperature sensors in the sensor unit so that a temperature sensor whose output becomes higher and a temperature sensor whose output becomes lower when the first race creeps are simultaneously generated. For example, it is also possible to mount only two temperature sensors, temperature sensor 10a and temperature sensor 10b, arranged at 180° intervals circumferentially, on circuit board 8, as shown in FIG. 10.

[0129] The number of temperature sensors arranged in the sensor unit may be four or more. The temperature sensors do not necessarily need to be arranged at equal intervals in the circumferential direction. The temperature sensors do not need to be arranged at 90° intervals in the circumferential direction, and can be arranged at intervals of, for example, 45°, 60°, 120°, etc.

[0130] In addition, in this bearing device, the first raceway 4 is the outer raceway, and the fitting portion 12 of the holder 9 is fitted to the circumferential surface portion 19 of the inner circumference thereof. However, it is also possible to use the first raceway as the inner raceway, and to fit the fitting portion of the holder to the circumferential surface portion of the outer circumference thereof. In this case, the first raceway has an outer circumference including a raceway surface portion and a circumferential surface portion that fits with the fitting portion. Therefore, when the first raceway is the inner raceway in the above-mentioned embodiment, the inside and outside in the radial direction only need to be understood in reverse, and illustrations and detailed explanations of these cases are omitted. That is, in the above-mentioned embodiment, if the cross-sectional structures depicted in the longitudinal front views of Figures 2 and 3 are rotated 180° counterclockwise to be turned upside down, and the upper side of the cross section of the first raceway in the upside-down view is the outer circumferential side of the inner ring, and the left side of the first raceway in the upside-down view is the axial one end side, then the case where the first raceway is the inner raceway is shown.

[0131] In addition, the creep detection means for the first race according to the present invention can be used even when the sensor unit is not fitted to the peripheral surface of the raceway surface side of the first race. That is, in the above-mentioned embodiment, the following supplementary inventions 1 and 2 are also disclosed. [Appendix 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 sensor unit fixed to the first bearing ring; The first raceway and the sensor unit are fitted together, the sensor unit has a plurality of temperature sensors; The plurality of temperature sensors are circumferentially spaced apart from one another, The bearing device further includes a creep determination unit that monitors the detection results of each of the temperature sensors and detects the simultaneous occurrence of a high temperature output from a first temperature sensor and a low temperature output from a second temperature sensor. [Appendix 2] 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 sensor unit fixed to the first bearing ring; The first raceway and the sensor unit are fitted together, the sensor unit has a plurality of temperature sensors; The plurality of temperature sensors are circumferentially spaced apart from one another, The bearing device further includes a creep determination unit that monitors which of the multiple temperature sensors detects the highest temperature, and detects whether the highest temperature has been detected by a temperature sensor other than the temperature sensor that previously detected the highest temperature.

[0132] In addition, in the above-mentioned embodiment, the following Supplementary Invention 3 is also disclosed. [Appendix 3] A bearing device according to any one of the above-mentioned configurations 1 to 10 or any one of the above-mentioned supplementary inventions 1 to 2, a shaft, and a housing, A rotating machine in which the rolling bearing supports a radial stationary load acting between the shaft and the housing.

[0133] In addition, in the above-mentioned embodiment, the following Supplementary Inventions 4 and 5 are also disclosed. [Appendix 4] A bearing device according to any one of the above configurations 1 to 10 or any one of the above supplementary inventions 1 to 3, and a computer, The bearing monitoring system has a creep determination unit in which the computer monitors the detection results of each of the temperature sensors and detects the simultaneous occurrence of a high temperature output from a first temperature sensor and a low temperature output from a second temperature sensor. [Appendix 5] A bearing device according to any one of the above configurations 1 to 10 or any one of the above supplementary inventions 1 to 3, and a computer, The bearing monitoring system has a creep determination unit in which the computer monitors which of the plurality of temperature sensors has detected the highest temperature, and detects whether the highest temperature has been detected by a temperature sensor other than the temperature sensor that previously detected the highest temperature.

[0134] The technical scope of the bearing device of this invention or the above-mentioned appended invention includes those in which arithmetic processing based on the outputs of multiple temperature sensors arranged in the sensor unit is performed by at least one of a computer that is physically connected to the sensor unit and a computer that is not physically connected to the sensor unit, and those that use one or both of a wired connection and a wireless connection as a medium for communication between the computer and the sensor unit, and those that use only the wireless communication circuit of the sensor unit when wirelessly connecting a computer and a physically discontinuous sensor unit, and those that perform the processing on a computer network of an appropriate scale from the wireless communication circuit of the sensor unit via a local net, the Internet, a mobile communication network, etc.

[0135] 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]

[0136] 1. Rolling bearings 2 Sensor unit 4 First raceway 5 Second bearing ring 6 Rolling elements 8 Circuit Board 9 Holder 10a, 10b, 10c Temperature sensors 11 Circular side 12 Fitting part 14 Stator (power supply) 15 First raceway surface section (raceway surface section) 16 Inner Circumference 18 Step section 19 Peripheral part 21 Side surface of the annular portion on the rolling element side 22 Side of the annular part on the side of the inverted moving body 24 Wireless communication circuits 27b Creep Judgment Section 27c Abnormal heat detection unit 27d Heat source detection unit

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 sensor unit fixed to the first bearing ring; the first raceway has an inner periphery or an outer periphery including a raceway surface portion and a peripheral surface portion that fits with the sensor unit, the sensor unit has a plurality of temperature sensors; The bearing device, wherein the plurality of temperature sensors are arranged at intervals from one another in the circumferential direction.

2. the sensor unit includes a circuit board including the plurality of temperature sensors and a holder that holds the circuit board; 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 is fitted to the circumferential surface portion of the first raceway, The inner circumference or the outer circumference including the raceway surface portion of the first race further includes a step portion that receives a side surface of the annular side portion on a rolling element side, 2. The bearing device according to claim 1, wherein the circuit board is disposed on a side surface of the annular side portion that faces the reversible moving body.

3. 3. The bearing device according to claim 1, further comprising a creep determination unit that monitors the detection results of each of the temperature sensors and detects the simultaneous occurrence of a rise in the output of a first temperature sensor and a fall in the output of a second temperature sensor.

4. 3. The bearing device according to claim 1, further comprising a creep determination unit that monitors which of the plurality of temperature sensors detects the highest temperature, and detects whether the highest temperature has been detected by a temperature sensor other than the temperature sensor that previously detected the highest temperature.

5. 3. The bearing device according to claim 1, wherein the sensor unit includes a wireless communication circuit and a power source.

6. The bearing device according to claim 1 or 2, further comprising an abnormal heat detection unit that detects a difference between outputs of the temperature sensors.

7. a heat source detection unit that identifies a phase of a heat source based on an output of each of the temperature sensors; 3. The bearing device according to claim 1, wherein the sensor unit has at least three of the temperature sensors as the plurality of temperature sensors.

8. 3. The bearing device according to claim 1, wherein two of the plurality of temperature sensors are arranged at 180° intervals in the circumferential direction.

9. 3. The bearing device according to claim 1, wherein the plurality of temperature sensors are arranged at equal intervals in the circumferential direction.

10. 3. The bearing device according to claim 1, wherein the plurality of temperature sensors are disposed within a range of an axial width of the first raceway.

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