JP2020193669A - Bearings with sensors and synchronous measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronous measurement system capable of acquiring a physical quantity related to a rotating device in association with a rotating position of the rotating device, and a bearing with a sensor using the system. SOLUTION: A sensor-equipped bearing 1 measures a physical quantity related to a bearing, a first sensor (acceleration sensor) that updates and holds a measured value in a first update cycle, and a rotation angle of the bearing. , The second sensor (angle sensor) that updates and holds the measured value in the second update cycle, and the measured value held by the first sensor and the measured value held by the second sensor are held by the first sensor. It also includes an acquisition unit that acquires the measured value in any of the second sensors in synchronization with the update completion timing. [Selection diagram] Fig. 5

Description

The present invention relates to bearings with sensors and synchronous measurement systems.

Conventionally, for the purpose of detecting an abnormality in a device, there are increasing cases of collecting information indicating whether the state of a rotating device is a normal state or an abnormal state. Abnormalities in rotating equipment mainly appear in temperature and vibration.
As a condition monitoring device for monitoring the state of a device including a rotating body, for example, there is a technique described in Patent Document 1. This technology analyzes the signal of a sensor installed in a device to detect any of vibration, sound, and acoustic emission, and diagnoses the abnormality of the device.

Japanese Unexamined Patent Publication No. 2018-36124

However, in the technique described in Patent Document 1, although it is possible to diagnose whether or not an abnormality has occurred in the rotating device, it is possible to specify the location where the abnormality has occurred (abnormality occurrence angle). Can't.
Therefore, an object of the present invention is to provide a synchronous measurement system capable of acquiring a physical quantity related to a rotating device in association with a rotating position of the rotating device, and a bearing with a sensor using the synchronous measurement system.

In order to solve the above problems, the sensor-equipped bearing according to one aspect of the present invention includes a bearing, a first sensor that measures a physical quantity related to the bearing, and updates and holds the measured value in the first update cycle. A second sensor that measures the rotation angle of the bearing and updates and holds the measured value in the second update cycle, a measured value held by the first sensor, and a measured value held by the second sensor. Is provided with an acquisition unit that acquires the measured value in synchronization with the update completion timing of the measured value in any of the first sensor and the second sensor.
As a result, the physical quantity related to the bearing can be obtained in association with the position (angle) of the bearing. Therefore, it is possible to appropriately grasp what kind of physical quantity is generated at which position (angle) of the bearing.

Further, in the bearing with a sensor, the first sensor is an acceleration sensor that measures the vibration of the bearing, and the second sensor measures the rotation angle of the inner ring with respect to the outer ring of the bearing. It may be an angle sensor.
In this case, the vibration of the bearing can be acquired in association with the position (angle) of the bearing.

Further, in the sensor-equipped bearing, unlike the first update cycle and the second update cycle, the acquisition unit is held by the measured value held by the first sensor and by the second sensor. The measured value may be acquired in synchronization with the update completion timing of the first sensor and the second sensor, whichever has the longer update cycle.
In this case, measured values close to the measurement timing can be acquired from the first sensor and the second sensor. Further, since the measured values acquired from each sensor can be the measured values after the update, the accuracy of the acquired data can be improved.

Further, in the bearing with a sensor, the acquisition unit includes a control unit that transfers a measured value held by the first sensor and a measured value held by the second sensor by DMA (Direct Memory Access). A recording unit that records the measured value of the first sensor and the measured value of the second sensor, which are DMA-transferred by the control unit, in association with each other may be provided.
In this case, since the measured value of the sensor can be written directly to the recording unit without going through the CPU, the load on the CPU can be reduced.

Furthermore, in the above-mentioned bearing with a sensor, at least one of the first sensor and the second sensor can output an update completion signal each time the update of the measured value is completed, and the control The unit may use the update completion signal output from any of the sensors capable of outputting the update completion signal as a trigger for the DMA transfer.
In this way, the update completion signal of the sensor may be used as an interrupt signal for starting DMA. As a result, the measured values of the first sensor and the second sensor can be reliably acquired in synchronization with the timing at which the measured values of any of the sensors are completed.

Further, in the bearing with a sensor, the recording unit may record the measured value without conversion. By recording the non-conversion data (raw data of the sensor) in the recording unit in this way, the data conversion process can be omitted, and the power consumption can be reduced accordingly.
Further, the bearing with a sensor may further include a transmission unit that transmits the measured value acquired by the acquisition unit to an external device. In this case, by analyzing the measured value with an external device, for example, it is possible to diagnose an abnormality of the bearing. At this time, the location (angle) at which the bearing abnormality occurs can also be specified.

Further, the sensor-equipped bearing includes a power generation unit that generates electric power based on the relative rotation of the outer ring and the inner ring of the bearing and supplies electric power to the first sensor, the second sensor, and the acquisition unit. You may also prepare. In this case, in a bearing with a sensor having a self-power generation function that does not require power supply from the outside, it is possible to appropriately acquire the correspondence data between the physical quantity and the rotation position (angle) related to the bearing.
Further, the synchronous measurement system according to one aspect of the present invention measures the physical quantity related to the rotating device, and measures the rotation angle of the rotating device with the first sensor that updates and holds the measured value in the first update cycle. , The second sensor that updates and holds the measured value in the second update cycle, the measured value held by the first sensor, and the measured value held by the second sensor are the first sensor and It includes an acquisition unit that acquires the measured value in any of the second sensors in synchronization with the update completion timing of the measured value.
As a result, the physical quantity related to the rotating device can be acquired in association with the position (angle) of the rotating device. Therefore, it is possible to appropriately grasp what kind of physical quantity is generated at which position (angle) of the rotating device.

According to one aspect of the present invention, since the physical quantity related to the rotating device (for example, the bearing) can be acquired in association with the rotating position of the rotating device, for example, the abnormal occurrence location (angle) of the bearing can be specified. Become.

FIG. 1 is a diagram showing an outline of a measurement system according to the present embodiment. FIG. 2 is a diagram showing an update cycle of each sensor in the first embodiment. FIG. 3 is a flowchart showing a procedure for acquiring measurement data. FIG. 4 is a diagram showing an example of measurement data. FIG. 5 is a diagram schematically illustrating a case where abnormality detection is performed in the first embodiment. FIG. 6 is a diagram showing an update cycle of each sensor in the second embodiment. FIG. 7 is a diagram schematically illustrating a case where abnormality detection is performed in the second embodiment. FIG. 8 is an exploded perspective view showing the configuration of the bearing with a sensor. FIG. 9 is an exploded perspective view showing the configuration of the bearing with a sensor. FIG. 10 is a plan view showing a configuration example of the cover and the coil substrate. FIG. 11 is a configuration example of a circuit board. FIG. 12 is an application example of the bearing with a sensor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiments, and can be arbitrarily changed within the scope of the technical idea of the present invention.

(First Embodiment)
In this embodiment, a measurement system that acquires measurement data in which a physical quantity related to a rotating device is associated with a rotating position (rotation angle) of the rotating device will be described.
This measurement system can be applied to, for example, a sensor-equipped bearing with a sensor. The bearing with a sensor includes a bearing, a first sensor that detects a physical quantity related to the bearing, and a second sensor that detects a rotation position (rotation angle) of the bearing. In this case, the measurement system acquires measurement data in which the physical quantity related to the bearing is associated with the rotation angle of the bearing. Here, the physical quantity can be an acceleration indicating vibration of the bearing. That is, the first sensor can be an acceleration sensor that detects the vibration of the bearing. The second sensor is an angle sensor that detects the relative rotation angle of the inner ring with respect to the outer ring of the bearing.

First, the outline of the measurement system will be described with reference to FIG.
Here, a case where the measurement system 200 acquires measurement data in which the vibration (acceleration) of the bearing and the position (rotation angle) are associated with each other will be described. The measurement system 200 includes a control unit 210, a measurement unit 220, and a recording unit 230.
The control unit 210 can be configured by a microcomputer (microcomputer). The control unit 210 includes a CPU 211 and a DMA controller (Direct Memory Access Controller: DMAC) 212. The measuring unit 220 includes an acceleration sensor 221 and an angle sensor 222. The recording unit 230 includes a memory 231. The recording unit 230 may be provided by the control unit 210.

The CPU 211 initializes the memory 231 and the sensors 221 and 222, and initializes the DMAC 212. When the DMAC212 inputs the DMA trigger, the DMAC212 starts the DMA transfer. Specifically, when the DMA trigger is input, the DMAC 212 keeps the latest measured values (sensor data) held by the acceleration sensor 221 and the angle sensor 222 as unconverted data (raw data) without going through the CPU 211. Transfer to memory 231.
The acceleration sensor 221 and the angle sensor 222 update and hold the measured values in the sensors at predetermined update cycles, respectively. The acceleration sensor 221 and the angle sensor 222 have a mechanism for transmitting the measured value held at that moment to the outside when there is a request for transmitting the measured value from the outside.

FIG. 2 is a diagram showing an update cycle of the acceleration sensor 221 and the angle sensor 222. In the present embodiment, it is assumed that the acceleration sensor 221 and the angle sensor 222 are set so that the update completion timings of the measured values are synchronized. That is, the update cycle of the acceleration sensor 221 (first update cycle) and the update cycle of the angle sensor 222 (second update cycle) are equal. The update cycle of the sensor is predetermined according to the performance of the sensor.

Further, in the present embodiment, the acceleration sensor 222 is set to output an interrupt signal (INT signal) to the DMAC 212 every time the measured value (acceleration) held inside the sensor is updated. The DMAC 212 uses the INT signal output from the acceleration sensor 222 as a DMA trigger to perform the DMA transfer described above.
In the present embodiment, the update completion timings of the measured values of the acceleration sensor 221 and the angle sensor 222 are the same. Therefore, the DMAC 212 acquires the acceleration data and the angle data, which are the measured values of the updated sensors, at the timing when the measured values of the acceleration sensor 221 and the angle sensor 222 are updated, and transfers them to the memory 231. ..

The memory 231 can be configured by, for example, SRAM or the like. The memory 231 may be a NAND type or NOR type flash memory or the like. The memory 231 stores the measured values (angle data, acceleration data) transferred from the DMAC 212. At this time, the memory 231 associates the angle data with the acceleration data on a one-to-one basis and stores them as measurement data.
In this way, the measurement system 200 acquires the measured value (acceleration data) of the acceleration sensor 221 and the measured value (angle data) of the angle sensor 222 in synchronization with the update completion timing of the measured value in the acceleration sensor 221. It functions as a synchronous measurement system for recording. In FIG. 1, the control unit 210 and the recording unit 230 correspond to the acquisition unit.

FIG. 3 is a flowchart showing the procedure of the measurement data acquisition process.
The process shown in FIG. 3 is started at the timing when power is supplied to the control unit 210 and the measurement unit 220, for example, when the user turns on the power.
First, in step S1, the CPU 211 initializes the acceleration sensor 221 and the angle sensor 222 and makes initial settings. Further, the CPU 211 performs the initial setting of the DMAC 212.
Next, in step S2, the sensors 221 and 222 determine whether or not the measurement start signal has been input. Then, the sensors 221 and 222 wait until the measurement start signal is input when the measurement start signal is not input, and when it is determined that the measurement start signal is input, the process proceeds to step S3 to start the measurement of the measured value. To do.

In step S4, the CPU 211 determines whether or not a predetermined measurement time has elapsed from the start of measurement. Here, the measurement time can be, for example, 1 second. The measurement time is set to be equal to or longer than the time required for the rotating wheel of the bearing to make at least one rotation. The measurement time can be appropriately set depending on the capacity of the recording unit 230 and the power consumption.
Then, when the CPU 211 determines that the above measurement time has not elapsed from the start of measurement, the process proceeds to step S5, and when it determines that the above measurement time has elapsed from the start of measurement, the CPU 211 proceeds to step S8. Transition.
Depending on the selection of the microcomputer, DMA may be executed in a state where the CPU operation is stopped (low power consumption mode). In that case, the passage of the measurement time may be monitored by a timer in the microcomputer, and the operation of the CPU may be stopped during the monitoring. By stopping the operation of the CPU, it is possible to construct a synchronous measurement system for angles and accelerations with lower power consumption.

In step S5, the DMAC 212 determines whether or not the INT signal has been received from the acceleration sensor 221. If the INT signal has not been received, the DMAC 212 determines that the DMA trigger has not been received and returns to step S4. On the other hand, when the DMAC 212 determines that the INT signal has been received from the acceleration sensor 221, the DMAC 212 determines that the DMA trigger has been received and proceeds to step S6.
In step S6, the DMAC 212 reads the acceleration data from the acceleration sensor 221 and the angle data from the angle sensor 222, and proceeds to step S7.
In step S7, the DMAC 212 transfers the measured values (acceleration data, angle data) read from the sensors 221 and 222 to the memory 231 and returns to step S4.

FIG. 4 is a diagram showing an example of measurement data stored in the memory 231.
As shown in FIG. 4, the memory 231 stores data corresponding to a plurality of angle data and acceleration data measured during the period from the start of measurement to the elapse of a predetermined measurement time.
In step S8, the CPU 211 transmits the measurement data stored in the memory 231 to the outside, and ends the process of FIG.

The measurement data transmitted by the measurement system 200 is used for, for example, in an external device of the transmission destination, for abnormality diagnosis of bearings. Specifically, as schematically shown in the left figure of FIG. 5, when the measurement data for three laps is acquired, the vibrations are added and averaged for each angle to be shown in the right figure of FIG. The result is obtained. Thereby, it can be specified that the acceleration peak exists at the angle D and the vibration different from the other angles is generated at the position of the angle D. In the present embodiment, if the acquisition cycle of the measurement data is shortened, substantially continuous data can be obtained.
By averaging the data measured a plurality of times in this way, noise can be mechanically removed and the feature amount can be extracted. Therefore, complicated processing for noise removal is not required, and tuning for each model and individual is not required, so that processing is easy.

In this embodiment, the case where the INT signal output by the acceleration sensor 221 at the timing of completing the update of the measured value is used as the DMA trigger has been described. However, the INT signal output by the angle sensor 222 at the timing of completing the update of the measured value may be used as the DMA trigger. When the update completion timings of the acceleration sensor 221 and the angle sensor 222 are synchronized as in the present embodiment, the acquired measurement data is the same regardless of which INT signal is used as the DMA trigger.

As described above, the measurement system 200 in the present embodiment acquires the measurement value held by the acceleration sensor 221 and the measurement value held by the angle sensor 222 in synchronization with the update completion timing of the measurement value in the acceleration sensor 221. can do. Therefore, it is possible to acquire measurement data in which acceleration data and angle data have a one-to-one correspondence. As a result, it is possible to appropriately grasp what kind of vibration is occurring at what angle during rotation, and it is possible to appropriately identify the location (angle) where the abnormality occurs.
Conventionally, when performing abnormality diagnosis of rotating equipment by monitoring vibration, it is assumed that the rotation speed is constant, and feature quantities such as peak value, effective value, and crest factor value are detected from the data of acceleration alone, and frequency analysis is performed. I was going. However, in reality, the rotation speed of the rotating device is not constant or is affected by noise. Therefore, in order to improve the accuracy of abnormality diagnosis due to vibration, measures such as reducing the influence of fluctuations in rotational speed and removing noise in rotational vibration data have been taken. However, for these measures, it is necessary to perform a process of determining the threshold value based on the data of the actual machine or the like. In addition, noise may remain only by numerical processing. Further, since it is a numerical process, there is a possibility that errors may be accumulated by repeating the process.

On the other hand, in the present embodiment, it is possible to acquire the measurement data in which the acceleration data and the angle data have a one-to-one correspondence, so that it is not necessary to worry about the variation in the rotation speed. Further, if the measurement data measured a plurality of times can be acquired, noise can be easily removed by mechanically averaging the data. Therefore, it is not necessary to determine the threshold value for signal processing as described above.
Furthermore, it is possible to easily identify the abnormal occurrence location (angle) that could not be specified by the data of the acceleration alone. Therefore, it becomes easy to utilize the abnormality diagnosis result for equipment maintenance and design improvement. It is also possible to monitor the progress of the abnormality by continuing the measurement.

Further, the measurement system 200 contributes to the miniaturization of the entire configuration by connecting the sensor to the microcomputer. Therefore, it is possible to store the measurement system 200 in the same housing even if it is a small device housing.
Further, the measured value acquired from each sensor can be recorded in the memory 231 as unconverted data. Therefore, at the time of data recording, data processing such as conversion from hexadecimal number notation to decimal number notation is unnecessary, and high-speed data storage is possible. In addition, the load due to data processing can be reduced, and the power consumption can be reduced.
Further, the measurement system 200 can include a DMAC 212 for DMA-transferring the measured values held by each sensor and a memory 231 for recording the measured values DMA-transferred by the DMAC 212. Since data acquisition and data storage can be performed by DMA transfer in this way, the load on the CPU 211 can be reduced.
That is, the measurement system 200 in this embodiment can be configured by an inexpensive MEMS sensor or a low power consumption microcomputer.

Further, if at least one of the acceleration sensor 221 and the angle sensor 222 can output an update completion signal each time the update of the measured value is completed, the update completion signal is output from any of the sensors capable of outputting the update completion signal. The signal can be a trigger for DMA transfer. For example, when the update completion signal of the acceleration sensor 221 is used as a trigger for DMA transfer, the DMA transfer of the measured values of the acceleration sensor 221 and the angle sensor 222 is executed in synchronization with the update completion timing of the measured values of the acceleration sensor 221. Can be done. In this way, it is possible to surely acquire the measured value of each sensor in synchronization with the timing when the measured value of any of the sensors is completed.

(Second embodiment)
Next, a second embodiment of the present invention will be described.
In the first embodiment described above, the case where the acceleration sensor 221 and the angle sensor 222 are set so that the update completion timings of the measured values are synchronized has been described. In the present embodiment, a case where the update cycle of the acceleration sensor 221 and the update cycle of the angle sensor 222 are different and the update completion timing of the measured value is set to be different will be described.

FIG. 6 is a diagram showing an update cycle of the acceleration sensor 221 and the angle sensor 222 in the present embodiment. In the present embodiment, it is assumed that the update cycle of the acceleration sensor 221 is set to be longer than the update cycle of the angle sensor 222. Further, it is assumed that both the acceleration sensor 221 and the angle sensor 222 can output an INT signal to the DMAC 212 at the timing when the measured value is updated.
In this way, when the update cycle of the acceleration sensor 221 and the update cycle of the angle sensor 222 are different, the INT signal output at the timing when the measured value is completed in the sensor having the longer update cycle is used as the DMA trigger. To do. That is, in the present embodiment, the INT signal output from the acceleration sensor 221 having a long update cycle is used as the DMA trigger.

In this way, by using the INT signal output from the sensor having the longer update cycle as the DMA trigger, it is possible to obtain a result close to the synchronous measurement. This point will be described in detail below.
When the INT signal of the acceleration sensor 221 is used as a DMA trigger, the DMAC 212 acquires the measured values of the acceleration sensor 221 and the angle sensor 222 at the time t1 and the time t3 of FIG. Here, the measured value of the acceleration sensor 221 acquired by the DMAC 212 at the time t3 is the measured value updated by the acceleration sensor 221 at the time t3. Further, the measured value of the angle sensor 222 acquired by the DMAC 212 at the time t3 is a measured value updated by the angle sensor 222 at the time t2. That is, there is a measurement timing error of the time width Δt1 between the acceleration data and the angle data acquired at the time t3.

On the other hand, when the INT signal of the angle sensor 222 is used as a DMA trigger, the DMAC 212 acquires the measured values of the acceleration sensor 221 and the angle sensor 222 every time the measured values of the angle sensor 222 are updated. However, the measured value of the acceleration sensor 221 is not updated from the time t1 to the time t3. Therefore, when the INT signal of the angle sensor 222 is used as a DMA trigger, the measured value of the acceleration data 221 acquired by the DMAC 212 at the time t1 and the measured value of the acceleration data 221 acquired by the DMAC 212 at the time t2 before the time t3. Have the same value. That is, a large measurement timing error such as a time width Δt2 occurs between the acceleration data and the angle data acquired at the time t2.

In this way, when the INT signal output from the sensor with the shorter update cycle is used as the DMA trigger, the measured value before the update is acquired from the sensor with the longer update cycle depending on the acquisition timing of the measured value. This will result in a large measurement error.
By using the INT signal output from the sensor having the longer update cycle as the DMA trigger as in the present embodiment, it is possible to acquire data having a small measurement timing error. That is, it is possible to obtain a result close to the synchronous measurement and improve the accuracy of the measurement data. In addition, since it is possible not to acquire measurement data with low accuracy, it is possible to reduce the power consumption by that amount and to save the power.

The measurement data acquired in this way can be used for abnormality diagnosis of bearings, for example, in an external device, as in the first embodiment described above. Specifically, as schematically shown in the left figure of FIG. 7, when the measurement data for three laps is acquired, it is shown in the right figure of FIG. 7 by performing the addition averaging of the vibrations for each angle. The result is obtained. Thereby, it can be specified that the acceleration peak exists at the angle D and the vibration different from the other angles is generated at the position of the angle D. In this embodiment, the acquisition cycle of the measurement data is slightly longer, so that discrete data can be obtained as compared with the first embodiment.

Here, the case where the acceleration sensor 221 having the longer update cycle can output the INT signal has been described, but when only the angle sensor 222 having the shorter update cycle can output the INT signal, the case has been described. The INT signal of the angle sensor 222 may be used as a DMA trigger. In this case, the measurement timing error is larger than when the INT signal of the acceleration sensor 221 is used as the DMA trigger, but it is possible to acquire the correspondence data between the acceleration data and the angle data.

(Example)
Hereinafter, examples of the present invention will be described.
8 and 9 are exploded perspective views showing the configuration of the bearing 1 with a sensor including the measurement system 200 described above. FIG. 8 is a view of the bearing 1 with a sensor viewed from the cover 10 side, and FIG. 9 is a view of the bearing 1 with a sensor viewed from the bearing 120 side.
The bearing 1 with a sensor includes a power generation unit 100 with a sensor and a bearing 120. The power generation unit 100 with a sensor is attached to one side surface of the bearing 120. The power generation unit 100 with a sensor includes a cover 10, a coil board 20, a rotating portion 30, a circuit board 40, and a back cover 60. Here, the back cover 60 is installed for the purpose of protecting the electronic circuit on the substrate. The back cover 60 may not be installed, and the substrate may be protected by a potting agent or the like.

The cover 10 is a ring-shaped flat plate member, and is magnetic such as, for example, silicon steel plate, carbon steel (JIS standard SS400 or S45C), martensitic stainless steel (JIS standard SUS420) or ferritic stainless steel (JIS standard SUS430). It is formed of a material having.
As shown in FIG. 9, a circuit board 40 is attached to the surface of the cover 10 facing the bearing 120. The circuit board 40 includes a power supply board 41 and a sensor board 42. The power supply board 41 and the sensor board 42 are fixed to the cover 10 by fastening bolts made of a non-magnetic material such as brass to the female screw holes formed in the cover 10, for example. In this case, the bolt has a length that does not protrude from the cover 10 when attached to the cover 10. The power supply board 41 and the sensor board 42 can be arbitrarily divided or integrated as needed.

Further, the cover 10 is provided with a through hole, and the through hole is sealed with a non-magnetic lid 17 formed of a non-magnetic material such as resin. As will be described later, the antenna 47 (see FIG. 10 described later) is mounted on the sensor substrate 42. Since the cover 10 has magnetism, it has a function of shielding electromagnetic waves from the antenna 47. However, the antenna 47 is arranged at a position facing the non-magnetic lid 17, so that the electromagnetic wave of the antenna 47 can reach the external communication unit via the non-magnetic lid 17.

The coil substrate 20 is attached to the surface of the cover 10 facing the bearing 120. The coil substrate 20 is fixed to the cover 10 via, for example, an adhesive.
FIG. 10 is a plan view showing a configuration example of the cover 10 and the coil substrate 20. The coil substrate 20 has a flexible substrate 21, a coil pattern 23 provided on the flexible substrate 21, and a plurality of yokes 25 provided on the flexible substrate 21. The installation of the yoke 25 is optional. The shape of the flexible substrate 21 in a plan view is a perfect circular ring centered on the rotation axis Ax. The coil pattern 23 has a plurality of flat coils laminated in the thickness direction of the flexible substrate 21. The flat coil is a pattern of a conductor provided by patterning on a predetermined surface of an insulator. In this embodiment, a conductor pattern is formed on a plurality of surfaces of the insulator. Not limited to this, the pattern of the conductor may be formed on one surface of the insulator. The number of turns of the coil pattern 23 is proportional to the number of laminated flat coils. In the present embodiment, the number of stacked flat coils may be changed to adjust the amount of power generation depending on the application of the power generation unit 100 with a sensor.
Further, the coil pattern 23 is extended so that irregularities are alternately arranged along the circumferential direction of the circle centered on the rotation axis Ax in a plan view. One yoke 25 is arranged in each of the concave and convex recesses. Since the angle sensor is arranged at a position where the magnetic change of the encoder magnet, which will be described later, can be detected, the coil pattern 23 may have a shape in which a part of the circle is chipped.

Further, the power supply board 41 and the sensor board 42 are attached to the outer peripheral side of the coil board 20 in a plan view. A power supply unit 43 is mounted on the power supply board 41. The power supply unit 43 converts the single-phase AC power supplied from the power generation unit 50 (see FIG. 11 described later) into a DC voltage and supplies it to the sensor substrate 42.

A sensor 44, a control circuit unit 45, and an antenna 47 are mounted on the sensor board 42. The sensor 44 includes, for example, an acceleration sensor 441, a temperature sensor 442, and an angle sensor 443. The sensor 44, the control circuit unit 45, and the antenna 47 may be composed of separate IC (Integrated Circuit) chips, or a part or all of them may be composed of one IC chip.

Further, although simplified in FIG. 10, both ends of the coil pattern 23 are connected to the power supply board 41 via the lead wire 16. In this embodiment, the coil pattern 23 and the power supply board 41 may be connected to each other via an FPC (Flexible Printed Circuit) connector instead of the lead wire 16. Alternatively, the coil board 20 may be extended and directly connected to the power supply board 41. Since soldering is not required for the connection using the FPC connector, the productivity of the power generation unit 100 with a sensor can be further increased.

Returning to FIGS. 8 and 9, the rotating portion 30 has a ring-shaped magnetic track 31, a ring-shaped base material 33, and a ring-shaped mounting jig 35. It is desirable that the base material 33 and the mounting jig 35 are magnetic metal materials. The magnetic track 31 is provided on one surface side of the base material 33. The mounting jig 35 is fixed to the other surface side of the base material 33. The mounting jig 35 projects from the other surface side of the base material 33 to one surface side of the base material 33 through a penetrating opening located in the center of the base material 33. One surface side of the base material 33 is the surface side facing the cover 10. The other surface side of the base material 33 is the surface side facing the back cover 60.
The magnetic track 31 may be detachable from the base material 33. Further, when the back cover 60 is not installed as described above, the magnetic track 31 may be provided on the bearing 120. In this case, for example, the magnetic track 31 may be press-fitted into the groove formed in the bearing 120.

In the present embodiment, the magnetic track 31 and the base material 33 are collectively referred to as an encoder magnet. For example, an encoder magnet is formed by forming a plastic magnet on one surface of a metal base material and alternately magnetizing north and south poles on the surface of the formed plastic magnet. The mounting jig 35 is used to mount the encoder magnet on the shaft portion that is passed through the power generation unit 100 with a sensor and the bearing 120.

The magnetic track 31 has a plurality of magnetic pole pairs 311 including N pole 31N and S pole 31S. The plurality of magnetic pole pairs 311 are arranged in the circumferential direction of the magnetic track 31. The north pole 31N and the south pole 31S are arranged alternately.
Further, the distance between the centers of the adjacent N poles 31N and the S poles 31S on the magnetic track 31 is the same as the distance between the centers of the adjacent yokes 25 on the coil substrate 20.

In the present embodiment, when the magnetic track 31 rotates relative to the coil substrate 20 about the rotation axis Ax (see FIG. 10), when one of the adjacent yokes 25 faces the north pole. The other yoke 25 faces the S pole. Further, when one yoke 25 faces the S pole, the other yoke 25 faces the N pole. That is, the adjacent yokes 25 of the coil substrate 20 do not face the same magnetic pole of the magnetic track 31. As a result, the phase of the change in the magnetic flux density passing through one yoke 25 and the phase of the change in the magnetic flux density passing through the other yoke 25 are shifted by 180 °.

In this way, when the magnetic track 31 rotates relative to the coil substrate 20, the magnetic poles facing the yoke 25 alternate. As a result, the magnetic flux density passing through the yoke 25 changes periodically. A voltage change (for example, a sinusoidal AC voltage) is generated in the coil pattern 23 located around the yoke 25 in response to the periodic change in the magnetic flux density.

FIG. 11 is a diagram showing a configuration example of the circuit board 40 included in the bearing 1 with a sensor. As described above, the circuit board 40 includes a power supply board 41 and a sensor board 42. Here, the sensor board 42 includes an angle sensor board 42a and a control board 42b.
The power supply board 41 includes a rectifier circuit 43a. The rectifier circuit 431 is included in the power supply unit 43 (see FIG. 10).

The power generation unit 50 includes a magnetic track 31 (see FIG. 8) and a coil substrate 20 (see FIG. 9). The power generation unit 50 generates electric power based on the relative rotation of the outer ring and the inner ring of the bearing 120, and supplies electric power to the sensor substrate 42.
The power generation unit 50 generates single-phase AC power and outputs it to the rectifier circuit 431. The rectifier circuit 431 full-wave rectifies the single-phase AC power generated by the power generation unit 50 and converts it into DC power. A diode bridge is exemplified as the rectifier circuit 431, but the present embodiment is not limited to this. The DC power output from the rectifier circuit 431 is smoothed by a smoothing circuit (not shown) to provide a stable power supply. After that, it is stored in a power storage circuit and a power storage device (not shown). The DC power stored in the capacitor is adjusted to a constant voltage by a constant voltage output circuit (not shown) at the timing of measurement, and then output to the sensor board 42.

The angle sensor 443 is mounted on the angle sensor board 42a of the sensor board 42. Further, the acceleration sensor 441, the microcomputer 451 and the external memory 452, and the wireless module (transmitter) 453 are mounted on the control board 42b of the sensor board 42. The microcomputer 451 and the external memory 452 and the wireless module 453 are included in the control circuit unit 45 (see FIG. 10).
The acceleration sensor 441 and the angle sensor 443 detect the acceleration and the rotation angle by using the DC power supplied from the power supply board 41.
For example, the angle sensor 443 is mounted on the angle sensor board 42a so as to be located on the side of the magnetic track 31. The rotating portion 30 having the magnetic track 31 is fixed to the inner ring of the bearing 120, and the angle sensor 443 detects the magnetic flux density that changes as the magnetic track 31 rotates together with the inner ring of the bearing 120, thereby detecting the magnetic flux density of the bearing 120. Detects the rotation angle of the inner ring with respect to the outer ring.
The type of the angle sensor 443 may be an incremental type or an absolute type.

The microcomputer 451 includes a CPU 451a, a DMAC 451b, and an internal memory 451c. The microcomputer 451 writes the measured value acquired from the sensor 44 to the external memory 452.
Here, the microcomputer 451 corresponds to the control unit 210 of FIG. That is, the CPU 451a corresponds to the CPU 211 of FIG. 1, and the DMAC451b corresponds to the DMAC 212 of FIG. Further, the sensor 44 corresponds to the measurement unit 220 of FIG. 1, and the external memory 452 corresponds to the recording unit 230 of FIG.

Under the control of the CPU 451a, the wireless module 453 transmits the data stored in the internal memory 451c and the external memory 452 to the outside. The wireless module 453 includes the antenna 47 of FIG. For example, the wireless module 453 transmits data to an external device by wireless communication. The transmitted data is received and processed by the communication unit of the external device.
In the present embodiment, the case where the sensor-equipped bearing 1 and the external device perform wireless communication has been described, but the communication standard does not matter as long as the sensor-equipped bearing 1 and the external device can communicate with each other. Absent. That is, data transmission from the bearing 1 with a sensor to the external device may be performed by wired communication.

Although the case where the measured value acquired from the sensor 44 is written to the external memory 452 has been described here, the measured value acquired from the sensor 44 may be written to the internal memory 451c, or the internal memory 451c and the external memory may be written. It may be used in combination with 452. Further, the internal memory 451c and the external memory 452 may be one memory.

As described above, the measurement system 200 in the present embodiment can be miniaturized and power-saving, and can be stored in a small device housing. Therefore, in the bearing 1 with a sensor using the magnetic encoder as described above, the measurement system 200 can be stored in a narrow space between the inner ring and the outer ring of the bearing, and the sensor device can be constructed in the same housing. become. It is also applicable to data wireless transmission type devices having a self-power generation function without external power supply.
As described above, the measurement system 200 applied to the data wireless transmission type sensor-equipped bearing 1 having the self-power generation function uses the minute electric power generated by the self-power generation function to measure the physical quantity related to the bearing to the rotation position (angle) of the bearing. ) Can be acquired and wirelessly transmitted to an external device.
Although the case of applying to the bearing 1 with a sensor having a self-power generation function has been described here, the power source may be an external power source.

Further, the bearing 1 with a sensor described above can be applied to, for example, a bearing portion of a water turbine.
FIG. 12 is a diagram showing a configuration of a Pelton turbine 300 including a bearing 1 with a sensor.
The Pelton turbine 300 includes an impeller (runner) 311. A large number of blades (buckets) 312 are provided on the outer circumference of the runner 311.
Further, the Pelton turbine 300 includes a plurality of nozzles 321 (two in FIG. 12). A needle valve 322 is arranged in each nozzle 321 so as to be movable back and forth. When the opening degree of the nozzle 321 is controlled by the needle valve 322 and water is injected from the tip of the nozzle 321, the blade 312 receives the water and the impeller 311 rotates. The Pelton turbine 300 generates electricity by rotating the impeller 311.

During the rotation of the impeller 311 the bearings vibrate when water hits each of the blades 312. At this time, if any abnormality has occurred in any of the plurality of blades 312 of the Pelton turbine 300, the vibration level when the blades 312 are exposed to water is the vibration level when the other blades 312 are exposed to water. It is different from the vibration level at the time.
Therefore, by installing the above-mentioned bearing 1 with a sensor in the bearing portion of the Pelton wheel 300, acquiring measurement data in which the vibration of the bearing and the rotation position (angle) are associated with each other, and analyzing the acquired measurement data, It is possible to identify which blade 311 has an abnormality. For example, when it is identified that an abnormality has occurred in the fourth blade 312, only the fourth blade 312 in which the abnormality has occurred can be repaired or replaced, and the maintenance cost can be reduced. ..

(Modification example)
In the above embodiment, the case where the rotating device is a bearing has been described, but the rotating device may be, for example, a gear. Also in this case, by connecting an acceleration sensor that measures the vibration of the gear and an angle sensor that measures the rotation angle of the gear to the microcomputer, measurement data that associates the vibration of the gear with the rotation position (angle) is acquired. The measurement system can be configured. In this case, based on the acquired measurement data, it is possible to diagnose which tooth of the gear has an abnormality.
Further, in the above embodiment, a case where an acceleration sensor for detecting an acceleration indicating vibration of the bearing is used as a physical quantity related to the bearing has been described, but the physical quantity is not limited to vibration (acceleration). For example, an ultrasonic sensor that detects the frictional noise generated in the bearing can also be used. Also in this case, it is possible to identify at which position (angle) of the bearing the abnormal noise is generated.

Further, in the above embodiment, the case of acquiring the measurement data in which the acceleration data and the angle data are associated with each other has been described, but the measurement data in which the acceleration data and the angle data are associated with three or more types of measured values are acquired. You can also do it. In this case, the measured values of the three or more types of sensors are acquired in synchronization with the update completion timing of the measured values in any of the sensors. For example, each measured value is acquired in synchronization with the update completion timing of the longer update cycle in at least two sensors of the three or more types of sensors.

Further, in the above embodiment, the case where the measurement data is used for the abnormality diagnosis of the bearing has been described, but the method of using the measurement data does not matter. That is, the measurement data can be used for purposes other than abnormality diagnosis.
For example, when the above-mentioned bearing 1 with a sensor is applied to the joint portion of the robot arm, it is possible to specify at what angle the robot arm causes vibration. Therefore, in this case, teaching may be performed so that the tip of the arm moves in a trajectory in which vibration does not occur.

The configuration of the synchronous measurement system described above is not limited to rotating equipment, and can be applied to, for example, a linear motion mechanism. When applied to a linear motion mechanism, the horizontal position and the physical quantity related to the device can be measured in synchronization.
Further, the above-mentioned synchronous measurement system is applicable not only to a system for synchronously measuring an angle (position) and another physical quantity, but also to a system for synchronously measuring a plurality of physical quantities measured by a plurality of different sensors. For example, it can be applied to a system that synchronously measures the pressure change and vibration of a fluid in a pipe in a factory. In this case, failure detection and prediction such as pipe breakage can be performed.

1 ... Bearing with sensor, 100 ... Power generation unit with sensor, 120 ... Bearing, 200 ... Measurement system, 210 ... Control unit, 211 ... CPU, 212 ... DMA controller (DMAC), 220 ... Measurement unit, 221 ... Acceleration sensor, 222 ... angle sensor, 230 ... recording unit, 231 ... memory

Claims (9)

Bearings and
A first sensor that measures physical quantities related to the bearing and updates and holds the measured values in the first update cycle.
A second sensor that measures the rotation angle of the bearing and updates and holds the measured value in the second update cycle.
The measured value held by the first sensor and the measured value held by the second sensor are synchronized with the update completion timing of the measured value in either the first sensor or the second sensor. A bearing with a sensor, which comprises an acquisition unit to acquire. The first sensor includes an acceleration sensor that measures the vibration of the bearing.
The sensor-equipped bearing according to claim 1, wherein the second sensor is an angle sensor that measures the relative rotation angle of the inner ring with respect to the outer ring of the bearing. Unlike the first update cycle and the second update cycle,
The acquisition unit
The measured value held by the first sensor and the measured value held by the second sensor are synchronized with the update completion timing in the longer update cycle of the first sensor and the second sensor. The sensor-equipped bearing according to claim 1 or 2, wherein the bearing is obtained. The acquisition unit
A control unit that transfers the measured value held by the first sensor and the measured value held by the second sensor by DMA (Direct Memory Access).
Any of claims 1 to 3, further comprising a recording unit that records the measured value of the first sensor and the measured value of the second sensor in association with each other and recorded by DMA transfer by the control unit. The bearing with a sensor according to item 1. At least one of the first sensor and the second sensor can output an update completion signal each time the update of the measured value is completed.
The control unit
The bearing with a sensor according to claim 4, wherein the update completion signal output from any of the sensors capable of outputting the update completion signal is used as a trigger for the DMA transfer. The bearing with a sensor according to claim 4 or 5, wherein the recording unit records the measured value without conversion. The bearing with a sensor according to any one of claims 1 to 6, further comprising a transmission unit that transmits the measured value acquired by the acquisition unit to an external device. The claim is further comprising a power generation unit that generates electric power based on the relative rotation of the outer ring and the inner ring of the bearing, and supplies electric power to the first sensor, the second sensor, and the acquisition unit. The bearing with a sensor according to any one of 1 to 7. A first sensor that measures physical quantities related to rotating equipment and updates and holds the measured values in the first update cycle.
A second sensor that measures the rotation angle of the rotating device and updates and holds the measured value in the second update cycle.
The measured value held by the first sensor and the measured value held by the second sensor are synchronized with the update completion timing of the measured value in either the first sensor or the second sensor. A synchronous measurement system characterized by having an acquisition unit for acquisition.

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