Bearing device and abnormality detection system

Abstract

To provide a bearing device capable of longer-time data communication.SOLUTION: A bearing device comprises: a bearing body including an outer ring and an inner ring; a power generation part for generating electricity by relative rotations of the inner ring and the outer ring; a power storage part for storing the electricity generated by the power generation part; a voltage detection part for detecting a power storage voltage of the power storage part; a sensor for detecting status values on the bearing body and outputting sensor signals; a data communication part for sending internal information based on data of the sensor signals output from the sensor or the power storage voltage, to an external device; and a control part to which the data and the power storage voltage from the voltage detection part, for controlling sending of the internal information. The control part decides a transmission operation of the internal information to the external device on the basis of at least one piece of information for decision among the power storage voltage detected by the voltage detection part, the data from the sensor, data acquired from the external device by communication, and previously stored data.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] 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. [Background technology]

[0002] 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 or outer ring of the bearing.

[0003] 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 on 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 the 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.

[0004] The AC voltage (electricity) generated by the generator is input into 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.

[0005] 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.

[0006] 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.

[0007] 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; 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 wireless communication transmission interval becomes. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-179440 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-131004 Summary of the Invention [Problem to be solved by the invention]

[0009] In the conventional technology of Patent Document 1, once transmission has started, transmission continues regardless of the stored voltage until the stored voltage falls below the first threshold. Because communication requires a relatively large amount of power, once transmission has started, if the power generation of the power generation unit has stopped or is insufficient, the stored voltage will sooner drop to a voltage at which transmission will stop, or it will sooner become impossible to maintain a voltage at which transmission is possible.

[0010] The prior art of Patent Document 2 also does not monitor the storage voltage and continues transmission regardless of the storage voltage, so if the power generated by 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, resulting in even greater 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.

[0011] 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. [Means for solving the problem]

[0012] The bearing device according to the present invention comprises: a power generating unit that generates electricity by relative rotation between the inner ring and the outer ring; a power storage unit that stores the electricity generated by the power generating unit; a voltage detecting unit that detects a stored voltage in 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 to an external device internal information based on data of the sensor signal output from the sensor or the stored voltage detected by the voltage detecting unit; and a control unit that receives input of the data and the stored voltage detected by the voltage detecting unit and controls the transmission of the internal information, The control unit determines the transmission operation of the internal information to the external device based on at least one of the judgment information among the storage voltage detected by the voltage detection unit, the data from the sensor, the data obtained by communication from the external device, and pre-stored data. Here, the control unit may perform, as the operation for determining the transmission operation, an operation for changing the cycle 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 storage voltage increases, and lengthen the transmission cycle as the storage voltage decreases.

[0013] 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.

[0014] Considering the above-mentioned change in the period, for example, if a relatively large amount of power is required for transmission 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 according to the present invention, when it is possible to assume (or estimate) from the determination information that the current or future storage voltage is high, 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 it is possible to assume from the determination information that the current or future storage voltage is low, the transmission period is set to the minimum (highest value), reducing the number of communications per unit time 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 according to the present invention is capable of data communication for a longer period of time.

[0015] The control unit (as described above, as a determining 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 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.

[0016] a rotation sensor that detects rotation of the inner ring or the outer ring as the sensor, and a rotation speed calculation unit that calculates a rotation speed from a signal from the rotation sensor in the control unit; 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, the control unit may, when the stored voltage is the same, 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 the same, the control unit may, when the stored voltage is the same, 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.

[0017] 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 the current or future storage voltage or may be capable of estimating the 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, and the shorter the transmission cycle is to maximize transmission. On the other hand, if the rotational speed is slow or the generated power estimated from the rotational speed is small, the longer the cycle is set, minimizing transmission and enabling continuous communication. This configuration enables data communication over a longer period of time.

[0018] The control unit may change the transmission period based on an operating pattern of the equipment in which the bearing device is incorporated, which is included in the pre-stored data, or an operating pattern included in data acquired by communication from the external device, and the stored voltage. In this case, a rotation sensor for detecting rotation of the inner ring or the outer ring is provided as the sensor, When the storage voltage is the same, the control unit may shorten the period for transmitting to the outside if it is estimated that the subsequent operating pattern will be maintained at a higher rotation speed, and may lengthen the period if it is estimated that the subsequent operating pattern will be maintained at a lower rotation speed.

[0019] In this configuration, the control unit changes the transmission cycle based on, in addition to the stored voltage, for example, an operating pattern of the equipment incorporating the bearing device, which is included in the pre-stored data, or an operating pattern included in data acquired via communication from the external device, which can estimate the (future) stored voltage. That is, if the subsequent operating pattern, which can be estimated from such an operating pattern, is estimated to maintain a higher rotation speed (even if the stored voltage is the same), the stored 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 stored voltage is considered to be low or its change trend is decreasing. Therefore, if the current or future stored voltage is estimated to be high based on the subsequent operating pattern, the control unit shortens the transmission cycle to maximize transmission. If the current or future stored voltage is estimated to be low, the control unit extends the transmission cycle to minimize transmission and perform operations to ensure continuous communication. This configuration enables data communication over a longer period of time.

[0020] The anomaly detection system according to the present invention comprises: In equipment incorporating any of the above bearing devices, 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 an abnormality in the equipment or the bearing is determined.

[0021] 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. [Effects of the Invention]

[0022] The bearing device according to the present invention enables data communication for a longer period of time. Furthermore, the abnormality detection system according to the present invention can improve the accuracy of abnormality detection in equipment, bearings, etc., in equipment incorporating the bearing device. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a front vertical cross-sectional view showing a main part of a bearing device according to a first embodiment of the present invention. [Figure 2A] FIG. 2 is a perspective view showing the overall appearance of the bearing device of FIG. [Figure 2B] 2B is a side view showing the bearing device of FIG. 2A with the cover of the sensor unit partially cut away. FIG. [Figure 3] FIG. 2 is an exploded perspective view of the sensor unit of FIG. 1. [Figure 4] FIG. 2 is a block diagram of a bearing with a wireless sensor, which is an example of the bearing device. [Figure 5] FIG. 6 is a block diagram of a bearing device with a wireless sensor, which is an example of a bearing device according to a second embodiment of the present invention. [Figure 6] FIG. 10 is a block diagram of a bearing device with a wireless sensor, which is an example of a bearing device according to a third embodiment of the present invention. [Figure 7] 7A to 7C are waveform diagrams showing an example of the operation of the bearing with wireless sensor of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0024] 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.

[0025] As shown in FIG. 1, this bearing device WB (FIG. 4, etc.) is a sensor-equipped bearing including 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.

[0026] 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.

[0027] 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 serves as the outer ring, a second raceway 5 which serves as the 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.

[0028] The sensor unit 2 is a unit that integrates a circuit board 8 and a holder 9 that holds the circuit board 8. The circuit board 8 includes electronic components (described below) of a data communication unit that performs data communication, a temperature sensor 10, and the like. 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.

[0029] 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.

[0030] The rolling bearing 1 of this embodiment is a radial bearing, such as a bearing with an inner ring that rotates. 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.

[0031] 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 the surfaces of the bearing rings 4, 5 that form the rolling paths of the rolling elements 6. In the illustrated example, they are continuous around the entire circumferential direction with a cross-sectional shape that forms a raceway groove corresponding to the diameter of the rolling elements 6.

[0032] 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 the 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) relative to each rolling element 6. To avoid interference between the sensor unit 2 and cage 7, the cage 7 does not have any part that is closer to the sensor unit 2 than the rolling elements 6. The sensor unit 2 does not have any part that protrudes axially from the rolling bearing 1.

[0033] 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 and completely around the circumference. The peripheral surface portion 19 is a cylindrical surface that extends axially and completely around the circumference.

[0034] 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 is 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).

[0035] 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 the annular side portion 11 and the fitting portion 12. The annular side portion 11 is an annular 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 machining.

[0036] 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. Small welds 22 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.

[0037] 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.

[0038] Temperature sensor 10 consists of a circuit that converts temperature into an electrical signal. Temperature sensor 10 is positioned axially opposite first raceway surface portion 15. As rolling bearing 1 rotates, it generates heat. One of the main causes of this heat generation is heat generated at the contact point between rolling elements 6 and first raceway ring 4. To enable this heat to reach temperature sensor 10 quickly and accurately, it is advisable to provide a heat conduction path consisting of a solid portion that continues axially from first raceway surface portion 15 to circuit board 8, preferably to temperature sensor 10, as shown in the figure.

[0039] 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 other sensor 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, it is possible to detect radial or axial acceleration to monitor vibrations of the rolling bearing 1. If an AE sensor is used, it is possible to detect elastic waves (AE waves) emitted when sound 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. Note that electronic components including a temperature sensor and an acceleration sensor may also be used.

[0040] 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 them 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.

[0041] 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 .

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Stator 14 guides the magnetic flux emitted from magnetic ring 13 through a yoke structure, inducing an AC voltage in coil 32 within the yoke structure. Stator 14 is provided in sensor unit 2. As shown in FIG. 3, the yoke structure of stator 14 is made up of holder 9 and yoke member 33 combined with annular side portion 11 of holder 9.

[0046] 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.

[0047] The yoke member 33 in Figure 3 has a seamless, integrated annular plate portion 35 that faces the mating 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 in Figure 1, the lower side) to the anti-mating portion 12 side (the side farther from the annular side portion 11, 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 interval in the circumferential direction toward the annular side portion 11 side (the left side in Figure 3).

[0048] 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 in opposite directions 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. 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.

[0049] 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 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.

[0050] 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.

[0051] 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 chafing prevention, a varnish treatment may be employed in which the coil 32 is coated by dipping it in varnish or by dripping varnish onto the coil 32. The bobbin 40 may also be omitted.

[0052] The magnetic flux emanating from the north pole of the magnet 29 shown in FIG. 2B enters the annular side portion 11 (or side plate portion 36) from the first claw pole portion 34 (or second claw pole portion 37) in FIG. 3, 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 magnetic flux direction 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.

[0053] 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 combining the holder 9 and the yoke member 33 in the axial direction, with each protrusion 39 of the yoke member 33 fitting into a corresponding hole 38 in 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 in a predetermined phase with gaps in the circumferential direction. This allows the holder 9 and the yoke member 33 to be properly combined without using a jig. Preferably, the holes 38 and the protrusions 39 are formed in three or more locations, respectively.

[0054] After this assembly, protrusion 39 is fixed to the inner surface of 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 protrusion 39 and hole 38. In this case, after coaxial alignment and phase alignment between the holder and yoke member are achieved 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 a combination of these may be used to fix them.

[0055] When holder 9 and yoke member 33 are combined and fixed as described above, stator 14 is completed as shown in Fig. 1. Note that, although an example has been shown in which annular plate portion 35 of yoke member 33 serves as a partition between the accommodation 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 radially inside the partition wall.

[0056] 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.

[0057] 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. These 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 generated by detecting voltage fluctuations in the power generation unit 3 as described above, 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.

[0058] 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 that is other sensor signal data than the sensor signal 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.

[0059] 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 the circuit components are driven with the generated power, 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 with 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 the power from the power storage unit 100.

[0060] Because communication requires a relatively large amount of power, if, for example, the power generation of 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.

[0061] 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 piece of determination information from 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) for transmitting the internal information to the external device OF based on the determination information as the operation for determining this transmission operation (however, the present invention is not limited to this example).

[0062] 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.

[0063] [Table 1]

[0064] 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 calculated linearly by interpolation. 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 slope is set at or above 0, or the minimum required cycle.

[0065] [Table 2]

[0066] 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 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.

[0067] [Table 3]

[0068] Next, we will explain another example. 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.

[0069] 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. Because 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 gradually changed in response to changes in the storage voltage and rotation speed. However, these values ​​may be included in a map or the like, read, 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.

[0070] [Table 4]

[0071] Here, using the block diagram in Fig. 5, we will explain how 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 in Fig. 5 is the same as in 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.

[0072] 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 calculated linearly by interpolation. These values ​​are determined by calculation, experiment, simulation, etc. 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.

[0073] [Table 5]

[0074] 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 in which the bearing device WB is incorporated, 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 this pre-stored operation pattern with data acquired from the outside. Unless otherwise specified, "pre-stored" means that it has been stored in advance in the memory unit 300 of the bearing device WB itself.

[0075] For example, "changing the transmission period (transmission period) based on the future operation pattern (of the equipment FC)" means that, when the operation patterns of the equipment FC during past operations (operations), such as the rotation speed R, storage voltage V, and transmission period T, are stored in the memory unit 300 or the external device OF, the stored past operation patterns are searched based on the current operation (movement) pattern and the immediately preceding operation pattern, and the stored past operation patterns are selected to be the closest, and the 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 bearing device WB via communication from the external device OF, or it may be input directly from the equipment FC to the bearing device WB via communication. Also, although it has been described above that a search is performed based on the current operating (motion) pattern and the immediately preceding operating pattern, the present invention is not limited to this, and for example, at a certain fixed point in the operating pattern, the external device OF or the facility FC may transmit a synchronization signal via communication to cause the bearing device WB to recognize which point in the pre-stored operating pattern it is at. Figure 6 is a block diagram illustrating the example of Figure 4, which is equipped with a memory unit 300.

[0076] 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 (sufficient power generation cannot be expected) in the future operating pattern, the period for transmitting to the outside will be lengthened.

[0077] 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 operating patterns, as in the example described above using FIG. 6. Between times 0 and Ta in FIG. 7, when a future operating pattern is estimated with reference to the selected past operating 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 operating pattern is estimated with reference to the past operating pattern, it is estimated that the low rotation speed R will continue from this point onwards, so the transmission cycle T is changed to Cc, which has a longer T.

[0078] 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. These values ​​are determined by calculation, experiment, simulation, etc. The cycle T to be set may be determined by taking into account 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.

[0079] As described above, by taking into consideration the storage voltage V at that time, the slope (change trend) of the storage voltage V, the rotation speed R, the generated power, and future operating patterns, etc., if the storage voltage or generated power is sufficient, more information is transmitted, and if the storage voltage or generated power is insufficient, transmission is possible for as long as possible while ensuring the minimum necessary cycle. This enables communication for a longer period even when the rotation speed is low or rotation has temporarily stopped, reducing the possibility of missing data acquisition when an abnormality occurs.

[0080] In equipment FC incorporating the bearing device WB of this embodiment described above, an anomaly detection system can be applied that time-aligns (matches) 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 detect abnormalities in the equipment FC or 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 and ensures time consistency between data from the bearing device WB and data from the external sensors. 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.

[0081] Although the embodiments of the present invention have been described above, the disclosed embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0082] 1. Bearings 3 Generator (power generating section) 4 outer ring 5. Inner Circle 24 Data Communications Department 100 Power storage unit 200 control section 300 Storage section FC equipment OF external device SS Sensor WB (Wireless) Sensor-Equipped Bearing (Bearing Device)

Claims

1. a power generating unit that generates electricity by relative rotation between the inner ring and the outer ring; a power storage unit that stores the electricity generated by the power generating unit; a voltage detecting unit that detects a stored voltage in 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 to an external device internal information based on data of the sensor signal output from the sensor or the stored voltage detected by the voltage detecting unit; and a control unit that receives input of the data and the stored voltage detected by the voltage detecting unit and controls the transmission of the internal information, the control unit determines a transmission operation of 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, the data acquired from the external device by communication, and pre-stored data. Bearing device.

2. 2. The bearing device of claim 1, The control unit, as a determining operation of the transmission operation, shortens the transmission cycle as the storage voltage increases, and lengthens the transmission cycle as the storage voltage decreases. Bearing device.

3. 2. The bearing device of claim 1, The control unit, as a determining operation of the transmission operation, shortens the transmission cycle if the change trend of the storage voltage is an upward trend, and lengthens the transmission cycle if the change trend of the storage voltage is a downward trend. Bearing device.

4. 2. The bearing device of claim 1, a rotation sensor that detects rotation of the inner ring or the outer ring as the sensor, and a rotation speed calculation unit that calculates a rotation speed from a signal from the rotation sensor in the control unit; the control unit changes 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, as the determination operation of the transmission operation. Bearing device.

5. The bearing device of claim 4, and when the storage voltage is the same, the control unit, as a determination operation of the transmission operation, shortens the transmission cycle as the rotation speed is faster and lengthens the transmission cycle as the rotation speed is slower. Bearing device.

6. The bearing device of claim 4, As a determination operation of the transmission operation, when the stored voltage is the same, 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. Bearing device.

7. 2. The bearing device of claim 1, the control unit, as a determination operation of the transmission operation, changes 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 the data acquired by communication from the external device, and the stored voltage. Bearing device.

8. The bearing device of claim 7, a rotation sensor for detecting rotation of the inner ring or the outer ring is provided as the sensor, As a determination operation of the transmission operation, when the storage voltage is the same, the control unit shortens the period of transmission to the outside when it is estimated that the subsequent operation pattern will be maintained at a higher rotation speed, and lengthens the period when it is estimated that the subsequent operation pattern will be maintained at a lower rotation speed. Bearing device.

9. In equipment incorporating the bearing device according to any one of claims 1 to 8, The data transmitted by the data communication unit is time-correlated with data of a sensor signal other than the sensor signal output from the sensor, and an abnormality in the equipment or the bearing is determined. Anomaly detection system.

Images