Bearing device and abnormality detection system

Abstract

Provided is a bearing device that is capable of performing data communication over a longer period of time. A bearing device according to the present invention comprises: a bearing body that includes an outer race and an inner race; a power generation unit that generates power through the relative rotation of the inner race and the outer race; a power storage unit that stores power generated by the power generation unit; a voltage detection unit that detects the stored power voltage of the power storage unit; a sensor that detects a status value pertaining to the bearing body and outputs a sensor signal; a data communication unit that transmits, to an external device, data of the sensor signal output from the sensor or internal information based on the stored power voltage; and a control unit that receives input of the stored power voltage from the voltage detection unit and the data and that controls transmission of the internal information, wherein the control unit determines, on the basis of at least one piece of information for determination among the stored power voltage detected by the voltage detection unit, the data from the sensor, data acquired from the external device through communication, and data stored in advance, an operation to transmit the internal information to the external device.

Description

Bearing device and abnormality detection system Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2024-051718, filed March 27, 2024, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a bearing device including a sensor unit that performs data communication with a bearing such as a rolling bearing, and to an abnormality detection system that uses the same.

[0003] Conventionally, there has been known, for example, a bearing device (also called a bearing with a sensor) in which a sensor unit is formed by mounting electronic components that perform data communication and sensors for detecting the state of the bearing on a circuit board or the like, and the sensor unit is fixed to the inner ring or outer ring of the bearing.

[0004] In a sensor-equipped bearing, for example, a generator and circuit board are placed on one end of a bearing used for inner ring rotation. The generator's stator is fixed to the outer ring of the bearing, and a coil is held in the stator. A magnetic ring magnetized with alternating north and south poles is fixed to the inner ring of the bearing as the generator's rotor. As the inner and outer rings of the bearing rotate relative to each other, electromagnetic induction generates an AC voltage in the coil, causing the generator to generate electricity. The power generated by the power generation unit is consumed, for example, in various parts of the bearing device, and can also be stored in a power storage unit. An (electronic) circuit board carrying various circuits, sensors, and communication devices such as wireless is fixed to the outer ring of the bearing, for example via the stator, and is further sealed with an electronic circuit protection material.

[0005] The AC voltage (electricity) generated by the generator is input to the power supply circuit. The power supply circuit rectifies the AC voltage to DC voltage, and then obtains the constant voltage necessary for the operation of sensors and electronic components. The sensors are acceleration sensors, temperature sensors, etc., and are driven at a constant voltage to obtain sensor signals of bearing status values ​​such as vibration acceleration and temperature, which are the state of the bearing. The rotational speed is obtained by processing the voltage fluctuations of the generator's output (typically the AC output). For example, rotational speed information can be obtained from the alternating frequency and peak voltage of the AC output.

[0006] The obtained sensor signal and rotational speed data are transmitted to an external device, for example, by electronic components that perform data communication on an (electronic) circuit board. In bearings with wireless sensors that perform wireless communication, the data is transmitted to the external device wirelessly according to standards such as Bluetooth Low Energy (2.4 GHz). The transmitted data is received by an external data collection device or the like.

[0007] Patent Document 1 discloses, as prior art, a rotating device that includes a power generation unit, a power storage unit, a voltage monitoring unit that monitors the voltage of the power storage unit, and a control unit, and that stops transmission of the communication circuit of the control unit when the voltage of the power storage unit charged with power generated by the power generation unit falls below a first threshold, and starts transmission of the communication circuit when the voltage rises above a second threshold that is higher than the first threshold.

[0008] Patent Document 2 discloses, as prior art, a bearing with a wireless sensor that includes a power generation unit and a secondary battery (power storage unit), a detection sensor that detects physical quantities provided in the bearing body, and a transmission processing unit that wirelessly transmits the detected information via radio communication, and when the direction of the detected information from the normal value side to the abnormal value side is defined as the abnormal value direction, the larger the value in the abnormal value direction, the shorter the radio communication transmission interval becomes.

[0009] JP 2019-179440 A JP 2016-131004 A

[0010] In the conventional technology of Patent Document 1, once transmission starts, transmission continues regardless of the storage voltage until the storage voltage falls below a first threshold. Because communication requires a relatively large amount of power, once transmission starts, if the power generation of the power generation unit is stopped or insufficient, the storage voltage will drop to a voltage that will stop transmission sooner, or it will become impossible to maintain a voltage that will allow transmission sooner.

[0011] Even in the conventional technology of Patent Document 2, since the storage voltage is not monitored and transmission continues regardless of the storage voltage, if the power generation of the power generation unit stops or is insufficient, the storage voltage will drop to a voltage that will stop transmission sooner or will not be able to maintain a voltage that will allow transmission. Furthermore, if the storage voltage increases toward an abnormal value, the communication interval will become shorter and the number of communications per unit time will increase, which will further increase power consumption, and there is a possibility that the storage voltage will drop before the data before and after the abnormality that should be recorded can be transmitted, making transmission impossible.

[0012] Therefore, an object of the present invention is to provide a bearing device capable of longer data communication periods in order to solve the above-mentioned conventional problems, and also to provide an abnormality detection system that can improve the accuracy of abnormality detection in equipment, bearings, etc., in equipment in which this bearing device is incorporated.

[0013] A bearing device according to the present invention comprises a bearing body including an outer ring and an inner ring, a power generation unit that generates electricity through relative rotation between the inner ring and the outer ring, a power storage unit that stores the electricity generated by the power generation unit, a voltage detection unit that detects the stored voltage of the power storage unit, a sensor that detects a state value related to the bearing body and outputs a sensor signal, a data communication unit that transmits internal information based on data of the sensor signal output from the sensor or the stored voltage detected by the voltage detection unit to an external device, and a control unit that receives the data and the stored voltage detected by the voltage detection unit and controls the transmission of the internal information, wherein the control unit determines an operation to transmit the internal information to the external device based on at least one determination information selected from the stored voltage detected by the voltage detection unit, the data from the sensor, data acquired by communication from the external device, and pre-stored data. Here, the control unit may, as an operation to determine the transmission operation, perform an operation to change the period at which the internal information is transmitted to the external device, and may perform specific changes as described in order below. For example, the control unit may shorten the transmission cycle as the stored voltage increases, and lengthen the transmission cycle as the stored voltage decreases.

[0014] In the bearing device according to the present invention, the control unit determines an operation for transmitting the internal information to the external device based on at least one piece of determination information selected from the stored voltage detected by the voltage detection unit, the data from the sensor, the data acquired by communication from the external device, and pre-stored data. Here, for example, the operation of "determining a transmission operation" may include an operation for changing the cycle at which the internal information is transmitted to the external device, an operation for preferentially transmitting abnormality information about the bearing device compared to previous operations, an operation for reducing the amount of information transmitted compared to previous operations, an operation for alternately transmitting multiple types of information instead of transmitting them previously (for example, two sets, although multiple sets per set may also be used), or an operation for sequentially transmitting multiple types of information instead of transmitting them previously.

[0015] Considering the above-mentioned change in the period, for example, if transmission requires a relatively large amount of power as described above, and power generation by the power generation unit is stopped or insufficient, the storage voltage may drop more quickly to a voltage at which transmission is stopped, or it may become impossible to maintain a voltage at which transmission is possible more quickly. However, in the bearing device of the present invention, when the current or future storage voltage is assumed (or estimated) to be high based on the determination information, the transmission period is shortened to enable transmission as much as possible, i.e., the number of communications per unit time is increased, and when the current or future storage voltage is assumed to be low based on the determination information, the transmission period is set to the minimum (highest value), and the number of communications per unit time is reduced as much as possible to enable communication to continue. With this configuration, the communication volume is adjusted taking into account the amount of power stored in the storage unit, so the bearing device of the present invention is capable of data communication for a longer period of time.

[0016] The control unit (as described above, as a determination operation of the transmission operation [the same applies below]) may shorten the transmission cycle if the change trend of the storage voltage is on an upward trend, and may lengthen the transmission cycle if the change trend of the storage voltage is on a downward trend. As a result, if the change trend of the storage voltage is on an upward trend, it can be assumed that the storage voltage will be high in the future, and the transmission cycle is shortened to enable as much transmission as possible, and if the change trend of the storage voltage is on a downward trend, the cycle is lengthened to reduce the number of communications per unit time as much as possible and perform an operation that allows communication to continue. This configuration enables data communication for longer periods of time.

[0017] The sensor may include a rotation sensor that detects rotation of the inner ring or the outer ring, and the control unit may include a rotation speed calculation unit that calculates a rotation speed from a signal from the rotation sensor, and the control unit may change the transmission cycle based on the rotation speed and the stored voltage, or based on the generated power estimated from the rotation speed and the stored voltage. In this case, when the stored voltage is constant, the control unit may shorten the transmission cycle as the rotation speed is faster and lengthen the transmission cycle as the rotation speed is slower. Furthermore, when the stored voltage is constant, the control unit may shorten the transmission cycle as the generated power estimated from the rotation speed is higher and lengthen the transmission cycle as the generated power estimated from the rotation speed is lower.

[0018] In this configuration, in addition to the storage voltage, the rotational speed of the bearing (the rotor, which is the inner ring or the outer ring) is referenced, which may correspond to or estimate the current or future storage voltage. That is, even if the storage voltage is the same, if the rotational speed is fast, the storage voltage is considered to be high or its change trend is upward, and if the rotational speed is slow, the storage voltage is considered to be low or its change trend is downward. Therefore, the faster the rotational speed or the greater the generated power estimated from the rotational speed, the higher the current or future storage voltage can be assumed to be. The transmission cycle is shortened to maximize transmission. The slower the rotational speed or the smaller the generated power estimated from the rotational speed, the longer the cycle is set, minimizing transmission and enabling continuous communication. This configuration enables data communication over a longer period of time.

[0019] The control unit may change the transmission cycle based on an operation pattern of the equipment in which the bearing device is incorporated, which is included in the pre-stored data, or an operation pattern included in data acquired by communication from the external device, and the stored voltage. In this case, the sensor includes a rotation sensor that detects rotation of the inner ring or the outer ring, and the control unit may shorten the transmission cycle to the outside when it is estimated that the subsequent operation pattern will be maintained at a higher rotation speed, if the stored voltage is the same, and lengthen the transmission cycle when it is estimated that the subsequent operation pattern will be maintained at a lower rotation speed.

[0020] In this configuration, the control unit changes the transmission period based on, for example, the storage voltage, as well as the operating pattern of the equipment incorporating the bearing device, which is included in the pre-stored data and can estimate the (future) storage voltage, or the operating pattern included in the data acquired via communication from the external device. That is, even if the storage voltage remains the same, if the subsequent operating pattern that can be estimated from the operating pattern is estimated to maintain a higher rotation speed, the storage voltage is considered to be high or its change trend is increasing. If the subsequent operating pattern is estimated to maintain a lower rotation speed, the storage voltage is considered to be low or its change trend is decreasing. Therefore, if the subsequent operating pattern indicates that the current or future storage voltage is high, the control unit shortens the transmission period to maximize transmission. If the current or future storage voltage is estimated to be low, the control unit extends the transmission period to minimize transmission and operate to ensure continuous communication. This configuration enables data communication over a longer period of time.

[0021] The abnormality detection system according to the present invention, in equipment incorporating any of the above-mentioned bearing devices, determines an abnormality in the equipment or the bearing by matching the data transmitted by the data communication unit with data acquired by the external device that is a sensor signal other than the sensor signal output from the sensor over time.

[0022] The anomaly detection system according to the present invention incorporates the bearing device, which is capable of longer data communication. The data transmitted by the data communication unit and data acquired by the external device that are sensor signals other than the sensor signal output from the sensor are time-matched. This ensures temporal consistency between the two sets of data, and allows the system to use all of the data before and after an anomaly that is intended to be recorded, without missing anything, allowing for adequate response to the anomaly and improving the accuracy of anomaly detection.

[0023] Any combination of at least two features disclosed in the claims and / or the specification and / or the drawings is included in the present invention. In particular, any combination of two or more features disclosed in the claims is included in the present invention.

[0024] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present invention, which is defined by the appended claims. In the accompanying drawings, the same reference numerals in multiple drawings indicate the same or corresponding parts.

[0025] Fig. 2B is a front longitudinal cross-sectional view showing a main part of a bearing device according to a first embodiment of the present invention. Fig. 3 is a perspective view showing the overall appearance of the bearing device of Fig. 1. Fig. 4 is a side view showing the bearing device of Fig. 2A with the cover of the sensor unit partially cut away. Fig. 5 is an exploded perspective view of the sensor unit of Fig. 1. Fig. 6 is a block diagram of a bearing with a wireless sensor as an example of the bearing device. Fig. 7 is a block diagram of a bearing with a wireless sensor as an example of a bearing device according to a second embodiment of the present invention. Fig. 8 is a block diagram of a bearing with a wireless sensor as an example of a bearing device according to a third embodiment of the present invention. Fig. 9 is waveform diagrams showing an example of operation of the bearing with a wireless sensor of Fig. 6 above.

[0026] An embodiment will be described in detail below with reference to the drawings. In the embodiments described below, when numbers, quantities, etc. are mentioned, the scope of the present disclosure is not necessarily limited to those numbers, quantities, etc., unless otherwise specified. The same reference numerals are used for the same or equivalent parts, and redundant descriptions may not be repeated. It is intended from the beginning that the configurations in the embodiments may be used in appropriate combinations.

[0027] As shown in FIG. 1, this bearing device WB (FIG. 4, etc.) is a sensor-equipped bearing comprising a bearing body (hereinafter also simply referred to as a bearing) 1 such as a rolling bearing, a sensor unit 2, and a generator 3.

[0028] Here, the circumferential direction centered on the central bearing axis (central rotation axis) of the rolling bearing 1 (not shown) is referred to as the "circumferential direction," the direction along the central bearing axis is referred to as the "axial direction," and the direction perpendicular to the central bearing axis is referred to as the "radial direction." In Figure 1, the axial direction corresponds to the left-right direction, and the radial direction corresponds to the up-down direction.

[0029] The structure of the sensor-equipped bearing will now be described. As shown in Figure 1, the rolling bearing 1 has a first raceway 4 which is an outer ring, a second raceway 5 which is an inner ring, 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.

[0030] The sensor unit 2 is a unit that integrates a circuit board 8 and a holder 9 that holds the circuit board 8. As shown in Figures 3 and 1, the circuit board 8 includes electronic components (described below) of a data communication unit that performs data communication, a temperature sensor 10, etc. The holder 9 has a substantially annular side portion 11 that extends radially and has a substantially circular ring shape, and a fitting portion 12 that protrudes axially from the annular side portion 11. The sensor unit 2 of this embodiment is fixed to the first bearing ring 4.

[0031] The generator 3 comprises a magnetic ring 13, also called a rotor, which is arranged so as to be rotatable integrally with the second bearing ring 5, and a stator 14 which faces the magnetic ring 13 and is fixed to the first bearing ring 4. The generator 3 generates electricity by electromagnetically converting the relative rotational motion between the first bearing ring 4 and the second bearing ring 5 into alternating current by the magnetic ring 13 and the stator 14.

[0032] The rolling bearing 1 of this embodiment is a radial bearing, for example, a bearing with an inner ring rotating. 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 an ISO or JIS standard. For example, the dimensions of radial bearings other than tapered roller bearings are specified in ISO 15 or JIS B 1512-1. Note that while FIG. 1 illustrates an example in which the rolling bearing 1 is configured as a deep groove ball bearing, the rolling bearing 1 is not limited to a deep groove ball bearing.

[0033] The first bearing ring 4 is usually arranged as a stationary ring. The second bearing ring 5 is usually arranged as a rotating ring. The first bearing ring 4 is an outer ring having an inner circumference 16 including a first raceway surface portion 15. The second bearing 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 surfaces of the bearing rings 4, 5 that form the rolling paths of the rolling elements 6, and in the illustrated example, are continuous around the entire circumferential direction with a cross-sectional shape that forms raceway grooves corresponding to the ball diameter of the rolling elements 6.

[0034] A predetermined distance is maintained between the rolling elements 6, cage 7, and sensor unit 2. This distance is set so that the sensor unit 2 will not come into contact with the rolling elements 6 or cage 7 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 side opposite the sensor unit 2 (the side facing away from the sensor unit 2, the left side in Figure 1) with respect to each rolling element 6. To avoid interference between the sensor unit 2 and cage 7, the cage 7 does not have any portion that is closer to the sensor unit 2 than the rolling elements 6. The sensor unit 2 does not have any portion that protrudes axially from the rolling bearing 1.

[0035] The inner periphery 16 of the first bearing ring 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 into the fitting portion 12 of the holder 9. The step portion 18 extends radially around the entire periphery. The peripheral surface portion 19 is a cylindrical surface that extends axially around the entire periphery.

[0036] As shown in Fig. 1 , the first raceway ring 4 has an end surface portion 20 located at one end of the axial width of the first raceway ring 4 (the right end in Fig. 1 ). The end 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 end surface portion 20. The circumferential surface portion 19 intersects with the step portion 18 at the other axial end of the circumferential surface portion 19 (the left end in Fig. 1 ).

[0037] The holder 9 is an annular body that, when attached to the first bearing ring 4, positions the circuit board 8 relative to the first bearing ring 4. The entire holder 9 is formed from a single metal plate, seamlessly integrating an annular side portion 11 and a fitting portion 12. The annular side portion 11 is an annular plate-shaped plate with both radially extending side surfaces along the entire circumferential direction. The fitting portion 12 extends axially from the end of the annular side portion 11 closest to the first bearing ring 4. For example, the entire holder 9 is press-formed. The metal plate forming the holder 9 is thick enough to stably hold the position of the circuit board 8 relative to the first bearing ring 4. The fitting portion 12 is fitted to a peripheral surface portion 19 of the first bearing ring 4. This positions the holder 9 with a predetermined degree of coaxiality with the first bearing ring 4. The peripheral surface portion 19 of the first bearing ring 4 is formed by cutting.

[0038] Depending on the required specifications for the arrangement of the temperature sensor 10 and other components held by the holder 9, it may be necessary to prevent the holder 9 from rotating in the circumferential direction relative to the first bearing ring 4. To meet these requirements, welds 22 are provided to join the holder 9 and the first bearing ring 4. If the welds 22 are small, they can be provided by laser welding. Although an example in which the welds 22 are provided around the entire circumferential circumference is shown (see FIGS. 2A and 2B ), they can also be provided as spot welds at multiple locations evenly spaced around the circumferential direction.

[0039] The circuit board 8 is a printed circuit board including the substrate 23 shown in FIGS. 2B and 3 , the temperature sensor 10 mounted on the substrate 23, a wireless communication circuit 24 serving as a data communication unit mounted on the substrate 23, a power supply circuit 25 mounted on the substrate 23, and one or more other sensors 26 mounted on the substrate 23. The circuit board 8 may further include a power storage unit for storing power generated by the power generation unit (described below), a data storage unit for storing data of sensor signals output from the sensors, and a control unit for controlling data storage and data communication (transmission and reception). The substrate 23 is shaped like an arc plate that is short in the radial direction and long in the circumferential direction. The temperature sensor 10, the wireless communication circuit 24, the power supply circuit 25, and one or more other sensors 26 are mounted on the surface of the substrate 23 facing the reversing body 6 (the right side in FIG. 1 ). As shown in FIGS. 2B and 3 , the substrate 23 is fixed to the annular side portion 11 with a plurality of screws 27.

[0040] The temperature sensor 10 consists of a circuit that converts temperature into an electrical signal. The temperature sensor 10 is positioned axially opposite the first raceway surface portion 15. The rolling bearing 1 generates heat as it rotates. One of the main causes of this heat generation is heat generated at the contact point between the rolling elements 6 and the first raceway ring 4. To enable this heat to reach the temperature sensor 10 quickly enough to detect temperature changes in the first raceway ring 4 quickly and accurately, it is advisable to provide a heat conduction path consisting of a solid portion that continues axially from the first raceway surface portion 15 to the circuit board 8, preferably to the temperature sensor 10, as shown in the figure.

[0041] The one or more other sensors 26 shown in Figures 2B and 3 are composed of circuits that convert physical or chemical quantities other than temperature into electrical signals. The type of the other sensors 26 is not particularly limited. For example, at least one selected from the group consisting of an acceleration sensor and an AE (Acoustic Emission) sensor is included among the one or more other sensors 26. If an acceleration sensor is used, radial or axial acceleration can be detected to monitor vibration of the rolling bearing 1. If an AE sensor is used, acoustic waves (AE waves) generated when a part of an object, such as a component of the rolling bearing 1, is deformed or damaged, or when an impact is applied, can be detected when the acoustic waves are emitted as elastic waves. Note that electronic components including a temperature sensor and an acceleration sensor may also be used.

[0042] The wireless communication circuit 24 is a communication circuit that converts predetermined information, such as the results of detection by the temperature sensor 10 and one or more other sensors 26, into radio waves and radiates the radio waves from an antenna 24a (FIG. 2B). The wireless communication circuit 24 conforms to 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.

[0043] The power supply circuit 25 is a circuit that converts AC power generated by the stator 14 of the generator 3 into DC power used on the circuit board 8 .

[0044] To protect the circuit board 8 from exposure to the outside, the sensor unit 2 is provided with a cover 28 shown in FIG. 2A that covers the opening for inserting the circuit board 8 onto the annular side portion 11.

[0045] The magnetic ring 13 shown in FIG. 1 has a magnet 29 magnetized with alternating north and south poles in the circumferential direction as shown in FIG. 2B and the core 30 of FIG. 1. The magnet 29 is formed of magnetic rubber extending in the circumferential direction. The magnet 29 is bonded to the core 30 around the entire circumferential direction. Vulcanization bonding can be used as the bonding method. The core 30 has a flange portion to increase its rigidity. Although the magnet 29 is exemplified as a magnetic material magnetized with multiple poles, it may also be composed of multiple permanent magnets.

[0046] The magnetic ring 13 is fixed to the outer periphery of the second bearing ring 5 by utilizing the stepped end 31 of the second bearing ring 5 so as not to protrude axially from the second bearing ring 5. By fitting the magnetic ring 13 onto the outer periphery of the second bearing ring 5, the second bearing ring 5 and the magnetic ring 13 are arranged coaxially. The stepped end 31 of the second bearing ring 5 is a portion for securing an annular space between the circumferential surface portion 19 of the first bearing ring 4 and the second bearing ring 5 that can accommodate the sensor unit 2 and the magnetic ring 13, and has a shape that radially expands the space between the circumferential surface portion 19 and the end of the second bearing ring 5 that faces this in the radial direction.

[0047] 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. As shown in FIG. 3 , the yoke structure of the stator 14 is made up of a holder 9 and a yoke member 33 combined with the annular side portion 11 of the holder 9.

[0048] 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 press-formed. The holder 9 has a first claw pole portion 34 that extends seamlessly and integrally from the annular side portion 11 on the side opposite the mating portion 12 (the side farther from the mating portion 12, or the lower side, in FIG. 1 ) to the same side as the mating portion 12 in the axial direction (the right side in FIG. 1 ) at regular intervals in the circumferential direction.

[0049] The yoke member 33 in Figure 3 has a seamless, integrated annular plate portion 35 that faces the fitting portion 12 in the radial direction, a side plate portion 36 that extends radially from the anti-annular side portion 11 side of the annular plate portion 35 (the side farther from the annular side portion 11, or the lower side in Figure 1) to the anti-fitting portion 12 side (the side farther from the annular side portion 11, or the right side in Figures 1 and 3), and a second claw pole portion 37 that extends axially from the side plate portion 36 at a regular circumferential interval toward the annular side portion 11 side (the left side in Figure 3).

[0050] The yoke structure of the stator 14 ( FIG. 1 ) 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. As shown in FIG. 2B , the first claw pole portion 34 and the second claw pole portion 37 face each other radially 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 axially opposite each other and alternately in the circumferential direction. A circumferential air gap is formed between adjacent first claw pole portions 34 and second claw pole portions 37 in the circumferential direction. The total number of first claw pole portions 34 and second claw pole portions 37 is equal to the number of poles (total number of north and south poles) of the magnet 29.

[0051] 3, arc-shaped holes 38 that axially penetrate 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 axially abutted against the annular side portion 11 at almost all portions except for the areas where these protrusions 39 are present.

[0052] 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.

[0053] At least a portion of the surface of the coil 32 and bobbin 40 may be in contact with the claw pole portions 34, 37, the annular side portion 11, and the side plate portion 36. To protect the magnet wire forming the coil 32 for the purposes of insulation, heat resistance, dust resistance, moisture resistance, and friction prevention, a varnish treatment may be employed in which the coil 32 is coated by dipping the coil 32 in varnish or by dripping varnish onto the coil 32. The bobbin 40 may also be omitted.

[0054] The magnetic flux emanating from the north pole of the magnet 29 shown in FIG. 2B enters, for example, the first claw pole portion 34 (or second claw pole portion 37) in FIG. 3 into the annular side portion 11 (or side plate portion 36), passes through the annular plate portion 35, circulates around the coil 32 to the side plate portion 36 (or annular side portion 11), and returns to the south pole of the magnet 29 via the adjacent second claw pole portion 37 (or first claw pole portion 34). When the north and south poles of the magnet 29 swap positions as the second bearing ring 5 rotates relative to the first bearing ring 4, the direction of the magnetic flux reverses. The alternating magnetic field thus generated generates an alternating voltage at both ends 41, 41 of the coil 32, at the beginning and end of the winding. The ends 41, 41 of the coil 32 in FIG. 3 are connected to terminals 42, 42 on the circuit board 23 through small wiring holes formed in the annular plate portion 35.

[0055] As shown in FIG. 3 , the sensor unit 2 is assembled by placing the bobbin 40, around which the coil 32 is wound, between the annular side portion 11 of the holder 9 and the side plate portion 36 of the yoke member 33, and then axially assembling the holder 9 and the yoke member 33, with each protrusion 39 of the yoke member 33 fitting into a corresponding hole 38 of the annular side portion 11. This fitting ensures that the holder 9 and the yoke member 33 are coaxial with each other, and also ensures that the first claw pole portions 34 and the second claw pole portions 37 are alternately arranged at a predetermined phase with gaps in the circumferential direction. This allows the holder 9 and the yoke member 33 to be appropriately assembled without using a jig. It is preferable that the holes 38 and the protrusions 39 are each formed in three or more locations.

[0056] After this assembly, the protrusion 39 is fixed to the inner surface of the hole 38. This fixing means may be, for example, press-fitting, bonding, laser welding, or a combination of these. It is also possible to omit the protrusion 39 and the hole 38. In this case, after coaxial alignment and phase alignment between the holder and the yoke member are achieved using a jig (not shown), the butting portions between the annular side portion and the annular plate portion may be bonded, or laser welding may be performed from the outer periphery of the annular plate portion, or a combination of these may be used for fixing.

[0057] When the holder 9 and the yoke member 33 are fixed in the assembled state as described above, the stator 14 is completed as shown in Fig. 1. Although the example shown uses the annular plate portion 35 of the yoke member 33 as a partition between the accommodation space for the circuit board 8 and the 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 radially inside the partition wall.

[0058] 4 is a block diagram of a bearing with a wireless sensor, which is an example of a bearing device according to this embodiment. The bearing with a wireless sensor WB comprises a bearing 1 and a power generation unit 3 that generates electricity through the relative rotation of an inner ring 5 and an outer ring 4 included in the bearing 1, and the electricity generated by the power generation unit 3 is stored in a power storage unit 100. The stored voltage of the power storage unit 100 is detected by a voltage detection unit 110 that includes an analog-to-digital conversion circuit and converted into a voltage value (stored voltage value) which is input to a control unit 200.

[0059] The bearing device WB includes a plurality of sensors, such as sensors A to C (collectively referred to as sensors SS), which detect and output status values ​​related to the bearing body 1. The output signals (sensor signals) are input to the control unit 200 as sensor signal data. In this embodiment, the status values ​​are, for example, internal conditions related to the bearing body 1 (such as vibration acceleration and temperature). The control unit 200 of this embodiment includes, as an example, a rotational speed calculation unit 210 that calculates the rotational speed based on a rotational speed signal from the rotational sensor rs. The rotational sensor rs detects voltage fluctuations in the power generation unit 3 and generates a rotational pulse signal (rotational speed signal) to output to the control unit 200. The rotational speed calculation unit 210 of the control unit 200 calculates the rotational speed based on the rotational pulse signal. While the rotational pulse is described above as being generated by detecting voltage fluctuations in the power generation unit 3, this is not limiting and may be generated by other methods, such as an electromagnetic pickup method or a Hall sensor method. The rotational sensor rs may also be included in the sensor SS.

[0060] The control unit 200 acquires state values ​​of the internal state of the bearing 1 from the (internal) data of the signal detected by the sensor SS, detects the state of the bearing 1 such as vibration acceleration and temperature, and controls the transmission and reception of internal information based on the sensor signal data output from the sensor SS or the stored voltage. This internal information is transmitted to the external device OF via a communication circuit (data communication unit) 24. The external device OF transmits communication commands to the bearing device WB from the outside, as well as data acquired by the external device OF and other sensor signal data other than the sensor signals output from the sensor SS of the bearing device WB. The other sensor signals are, for example, output signals from external sensors attached to the external device OF.

[0061] The power generated by the power generation unit 3 is stored in the power storage unit 100 as described above, and is then supplied from the power storage unit 100 to each unit such as the sensor SS, the control unit 200, and the data communication unit 24. If the power generated by the power generation unit 3 is sufficient to drive all of the circuit components, such as the electronic components on the circuit board 8, surplus power is generated and is used to drive the circuit components, while the surplus power is stored in the power storage unit 100. If the power generated is insufficient to drive all of the circuit components, all of the circuit components are driven by power from both the power generation unit 3 and the power storage unit 100. Note that when the power generation unit 3 is not generating power, all of the circuit components are driven by power from the power storage unit 100.

[0062] Because communication requires a relatively large amount of power, if, for example, the power generated by the power generation unit 3 stops or is insufficient after transmission has started, the stored voltage will drop more quickly to a voltage at which transmission stops, or it will become impossible to maintain a voltage at which transmission is possible. In such cases, or if power consumption becomes even greater, the stored voltage may drop before the data before and after the abnormality that should be recorded can be transmitted, making transmission impossible. Therefore, to solve this problem, the bearing device WB of this embodiment needs to be able to communicate data for a longer period of time.

[0063] Therefore, the bearing device WB of this embodiment determines the transmission operation of the internal information to the external device based on at least one of the determination information items among the stored voltage value detected by the voltage detection unit 110, the (internal) data of the sensor signal from the sensor, the data obtained by communication from the external device OF, and pre-stored data. Below, an example will be described in which the control unit 200 of the bearing device WB changes the cycle (hereinafter also referred to as the transmission cycle) at which the internal information is transmitted to the external device OF based on the determination information as the operation for determining the transmission operation (however, the present invention is not limited to this example).

[0064] A specific example of how the control unit 200 changes the transmission cycle will be described using FIG. 4. First, an example of shortening the transmission cycle as the storage voltage increases and lengthening the transmission cycle as the storage voltage decreases will be described using Table 1. In Table 1, the transmission cycle is changed in stages in response to changes in the storage voltage, but these values ​​may be included in a map or the like, read out, and calculated linearly by interpolation. These values ​​are determined by calculation, experiment, simulation, etc. The cycle is set in this way to ensure that communication can be continued as much as possible while ensuring the minimum necessary cycle, so that transmission is performed as much as possible when the storage voltage is high and transmission is reduced as much as possible when the storage voltage is low.

[0065]

[0066] As another example, the control unit 200 may shorten the transmission cycle if the storage voltage change trend is upward, and may lengthen the transmission cycle if the storage voltage change trend is downward. Table 2 shows an example. In Table 2, the transmission cycle is changed in stages in response to changes in storage voltage, but such values ​​may be included in a map or the like, read out, and interpolated to calculate linearly. Such values ​​are determined by calculation, experiment, simulation, or the like. The cycle is set as short as possible so that, for example, when the storage voltage change trend is upward, the slope remains at or above 0, i.e., communication can be maintained, and when the storage voltage change trend is downward, the cycle is set so that the slope remains at or above 0, or the minimum required cycle is set.

[0067]

[0068] Furthermore, the control unit 200 may determine the transmission period taking into consideration both the current storage voltage and the slope of the storage voltage. An example of this is shown in Table 3. In Table 3, the transmission period is changed in stages in response to changes in the storage voltage and the slope of the storage voltage, but these values ​​may be included in a map or the like, read out, and calculated linearly by interpolation. These values ​​are determined by calculation, experiment, simulation, etc. The period to be set is set in this way, taking into consideration the slope of the storage voltage while being based on the storage voltage, based on the two examples already described above.

[0069]

[0070] Next, another example will be described. Based on the rotation speed and stored voltage from the rotation sensor rs in Fig. 4 or the generated power and stored voltage estimated from the rotation speed by the generated power estimation unit 230 (Fig. 5), the control unit 200 changes the period for transmitting the internal information to the external device OF.

[0071] As a specific example, a method for changing the period for transmitting internal information to the outside based on the storage voltage and rotation speed will be described. Since the power generated by the power generation unit 3 increases as the rotation speed increases, for example, even if the storage voltage is the same, the faster the rotation speed, the shorter the period for transmitting to the outside, and the slower the rotation speed, the longer the period for transmitting. Table 4 shows an example. In Table 4, the transmission period is changed in stages in response to changes in the storage voltage and rotation speed. However, these values ​​may be included in a map or the like, read out, and linearly calculated by interpolation. These values ​​are determined by calculation, experiment, simulation, or the like. The transmission period is set as short as possible when, for example, the rotation speed is so fast that a short transmission period can cover the power required and still provide sufficient charging power for the storage unit 100, or when the storage unit 100 is nearly fully charged and the rotation speed is so fast that a short transmission period can cover the power required. Otherwise, the transmission period is set to a value that maintains the storage voltage or allows communication to continue as long as possible at the rotation speed at that time while ensuring the minimum necessary transmission period.

[0072]

[0073] Here, using the block diagram of Fig. 5, a method will be described in which the control unit 200 changes the period for transmitting internal information to the outside based on the generated power and stored voltage estimated from the rotation speed. The basic configuration of Fig. 5 is the same as that of Fig. 4, but the control unit is provided with a generated power estimation unit 230, which estimates the generated power from the rotation speed of the rotation sensor rs. The generated power can be estimated by calculation using various parameters of the generator, or by using information obtained through simulations, experiments, etc.

[0074] For example, even if the storage voltage is the same, the greater the estimated generated power, the shorter the external transmission cycle, and the smaller the generated power, the longer the transmission cycle. Table 5 shows a specific example. In Table 5, the transmission cycle is changed in stages in response to changes in storage voltage and generated power. These values ​​may be included in a map or the like, read out, and linearly calculated by interpolation. These values ​​are determined by calculation, experiment, simulation, or the like. The cycle to be set is determined, for example, by taking into consideration the balance between the power consumption of the electrical circuit when communication is performed at that cycle and the storage voltage and estimated generated power at that time, and by shortening the transmission cycle as much as possible when there is room, and by ensuring the minimum necessary cycle when there is not enough room, so as to ensure that communication can be continued as much as possible.

[0075]

[0076] 6, an example will be described in which the control unit 200 changes the transmission period based on pre-stored data such as the operation pattern of the equipment FC incorporating the bearing device WB, or data such as the operation pattern acquired by communication from the external device OF, and the stored voltage. Here, a method will be described in which the transmission period is changed based on the stored voltage and the pre-stored (future) operation pattern of the equipment FC. The example of the (future) operation pattern of the equipment FC acquired by communication from the external device OF is omitted here, as it simply replaces the pre-stored operation pattern with data acquired from the outside. Unless otherwise specified, "pre-stored" means that the data has been pre-stored in the memory unit 300 of the bearing device WB itself.

[0077] For example, "changing the transmission period (transmission period) based on the future operation pattern (of the equipment FC)" means that, when operation patterns of the equipment FC such as the rotation speed R, storage voltage V, and transmission period T during past operations (activity) are stored in the memory unit 300 or the external device OF, the stored past operation patterns are searched from the current operation (movement) pattern and the immediately preceding operation pattern, and the one that is considered to be the closest is selected, and a future operation pattern is estimated from the closest past operation pattern to determine (and change) the future transmission period. Note that the operation pattern may be an operation pattern set in the equipment FC that is pre-stored in the memory unit 300 of the bearing device WB itself and read each time, or it may be pre-stored in a storage device (not shown) of the external device OF and input via communication from the external device OF. Furthermore, the operation pattern may be determined by communication between the equipment FC and the external device OF, and the information (operation pattern) may be input from the external device OF to the bearing device WB via communication, or may be input by communication directly from the equipment FC to the bearing device WB. Also, while it has been described above that the search is based on the current operation (movement) pattern and the immediately preceding operation pattern, this is not limited to this. For example, at a certain point in the operation pattern, the external device OF or the equipment FC may transmit a synchronization signal via communication, thereby allowing the bearing device WB to recognize which point in a pre-stored operation pattern it is. Figure 6 is a block diagram illustrating the example of Figure 4, which includes a memory unit 300.

[0078] For example, even if the storage voltage is the same, if it is estimated that the rotation detected by the rotation sensor rs will maintain a higher rotation speed in the future operating pattern (sufficient power generation can be expected), the period for transmitting to the outside will be shortened, and if it is estimated that the rotation will be maintained at a lower rotation speed or stopped in the future operating pattern (sufficient power generation cannot be expected), the period for transmitting to the outside will be lengthened.

[0079] FIG. 7 shows an example of a waveform diagram in which the transmission cycle T is changed based on the stored voltage and stored past driving patterns, as in the example described above using FIG. 6 . Between times 0 and Ta in FIG. 7 , when a future driving pattern is estimated by referring to the selected past driving pattern that is considered to be the closest, the stored voltage V is low, but it is estimated that the rotation speed R will increase after time Ta, so the transmission cycle T is set to a shorter Ca. Between times Ta and Tb, the rotation speed R is high, so sufficient power generation is achieved, and the transmission cycle T is changed to Cb, which has the shortest T. After time Tb, although the stored voltage V is high, when a future driving pattern is estimated by referring to the past driving pattern, it is estimated that the low rotation speed R will continue from this point onward, so the transmission cycle T is changed to Cc, which has a longer T.

[0080] While ensuring the minimum necessary cycle, if a high rotation speed R is to be maintained according to the future operating pattern, a short transmission cycle T is set, and if a low rotation speed R is to be maintained, a long transmission cycle T is set so that communication can be continued as much as possible even if the storage voltage V is high. Such values ​​are determined by calculation, experiment, simulation, etc. The cycle T to be set may be determined by referring to the storage voltage V at that time and the future operating pattern, as well as the power consumption of each part of the bearing device WB when communication is performed at that cycle T.

[0081] As described above, the system takes into consideration the current storage voltage V, the slope (change trend) of the storage voltage V, the rotational speed R, the generated power, and future operating patterns, etc., and transmits more information when the storage voltage or generated power is sufficient, and transmits for as long as possible while maintaining the minimum necessary cycle when the storage voltage or generated power is insufficient. This enables communication for a longer period of time even when the rotational speed is low or rotation has temporarily stopped, reducing the possibility of missing data acquisition when an abnormality occurs.

[0082] In equipment FC incorporating the bearing device WB of this embodiment as described above, an anomaly detection system can be applied that time-aligns (corresponds to) internal information, such as the data transmitted by the data communication unit 24, with data acquired by the external device OF, such as data from other sensor signals other than the sensor signal output from the sensor SS, to determine abnormalities in the equipment FC or the bearing 1 (such as noise or heat generated due to abnormal vibration or abnormal friction). Equipment FC incorporating a bearing device WB that achieves the effects described in this specification enables longer data communication periods, and ensures temporal consistency between the data from the bearing device WB and the data from the external sensor. This improves the accuracy of anomaly detection. Note that other configurations, virtually identical to those described, that are conceivable to those skilled in the art, may also be applied to the equipment FC and the anomaly detection system.

[0083] As described above, the preferred embodiment has been described with reference to the drawings, but various additions, modifications, and deletions can be made without departing from the spirit of the present invention. Therefore, such additions, modifications, and deletions are also included in the scope of the present invention.

[0084] REFERENCE SIGNS LIST 1 Bearing 3 Generator (power generating unit) 4 Outer ring 5 Inner ring 24 Data communication unit 100 Power storage unit 200 Control unit 300 Memory unit FC Equipment OF External device SS Sensor WB (Wireless) sensor-equipped bearing (bearing device)

Claims

1. A bearing device comprising: a bearing body including an outer ring and an inner ring; a power generation unit that generates electricity through the relative rotation of the inner ring and the outer ring; a power storage unit that stores the electricity generated by the power generation unit; a voltage detection unit that detects the stored voltage of the power storage unit; a sensor that detects a status value related to the bearing body and outputs a sensor signal; a data communication unit that transmits to an external device internal information based on the sensor signal data output from the sensor or the stored voltage detected by the voltage detection unit; and a control unit that receives the data and the stored voltage detected by the voltage detection unit and controls the transmission of the internal information, wherein the control unit determines an operation to transmit the internal information to the external device based on at least one piece of judgment information selected from the stored voltage detected by the voltage detection unit, the data from the sensor, data acquired by communication from the external device, and pre-stored data.

2. A bearing device according to claim 1, wherein the control unit determines the transmission operation by shortening the transmission cycle as the stored voltage increases and lengthening the transmission cycle as the stored voltage decreases.

3. A bearing device according to claim 1, wherein the control unit, as a determining operation for the transmission operation, shortens the transmission cycle if the change trend of the stored voltage is on the rise, and lengthens the transmission cycle if the change trend is on the fall.

4. A bearing device according to claim 1, wherein the sensor is a rotation sensor that detects rotation of the inner ring or the outer ring, and the control unit is provided with a rotation speed calculation unit that calculates the rotation speed from a signal from the rotation sensor, and the control unit changes the transmission cycle as a determination operation for the transmission operation based on the rotation speed and the stored voltage, or based on the generated power estimated from the rotation speed and the stored voltage.

5. A bearing device according to claim 4, wherein the control unit, as a determining operation for the transmission operation, shortens the transmission cycle as the rotation speed increases and lengthens the transmission cycle as the rotation speed decreases, when the stored voltage is the same.

6. A bearing device according to claim 4, wherein, as a determining operation for the transmission operation, the control unit shortens the transmission cycle as the generated power estimated from the rotation speed increases, and lengthens the transmission cycle as the generated power estimated from the rotation speed decreases, when the stored voltage is the same.

7. A bearing device according to claim 1, wherein the control unit, as a determination operation for the transmission operation, changes the transmission cycle based on the operation pattern of the equipment in which the bearing device is incorporated, which is contained in the pre-stored data, or the operation pattern contained in the data acquired by communication from the external device, and the stored voltage.

8. A bearing device according to claim 7, wherein the sensor comprises a rotation sensor that detects rotation of the inner ring or the outer ring, and the control unit, as a determination operation for the transmission operation, shortens the period for transmitting to the outside if it is estimated that the subsequent operating pattern will be maintained at a higher rotation speed when the stored voltage is the same, and lengthens the period if it is estimated that the subsequent operating pattern will be maintained at a lower rotation speed.

9. An abnormality detection system for equipment incorporating a bearing device according to any one of claims 1 to 8, wherein the data transmitted by the data communication unit is time-correlated with data acquired by the external device that is a sensor signal other than the sensor signal output from the sensor, and determines whether there is an abnormality in the equipment or the bearing.

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