US-12620833-B2 - Monitoring device

US12620833B2US 12620833 B2US12620833 B2US 12620833B2US-12620833-B2

Abstract

A monitoring device includes a vibration-driven energy harvesting element as a vibration-driven energy harvesting unit that performs power generation in response to a sound or a vibration being occurred by a monitoring target and having a predetermined frequency, and a notification unit that notifies a state change of the monitoring target based on a magnitude relationship between a predetermined threshold value and a voltage value of the power generation by the vibration-driven energy harvesting element. The notification unit is configured to notify the state change when the vibration-driven energy harvesting element performs the power generation. Therefore, the vibration-driven energy harvesting element, which functions as a sensor unit, requires no power supply.

Inventors

Hiroyuki Mitsuya
Hisayuki ASHIZAWA
Takuro Ishikawa

Assignees

SAGINOMIYA SEISAKUSHO, INC.

Dates

Publication Date: 20260505
Application Date: 20220324
Priority Date: 20210422

Claims (12)

1 . A monitoring device comprising: a vibration-driven energy harvesting unit that performs power generation in response to a sound or a vibration being occurred by a monitoring target and having a predetermined frequency; a notification unit that notifies a state change of the monitoring target based on a magnitude relationship between a predetermined threshold value and a voltage value of the power generation by the vibration-driven energy harvesting unit; and a switch unit configured to activate the notification unit when the voltage value is greater than or equal to the predetermined threshold value, and to deactivate the notification unit when the voltage value is less than the predetermined threshold value, wherein the vibration-driven energy harvesting unit functions as both a vibration sensor and a power source without requiring an external power supply.
2 . The monitoring device according to claim 1 , wherein the notification unit is activated in response to a switch in the magnitude relationship between the predetermined threshold value and the voltage value of the power generation and notifies the state change of the monitoring target.
3 . The monitoring device according to claim 1 , further comprising: a power supply for operating the notification unit; and wherein the switch unit is configured to permit supply of electric power from the power supply to the notification unit when the voltage value of the power generation is greater than or equal to the predetermined threshold value and that shuts off the supply of electric power from the power supply to the notification unit when the voltage value of the power generation is less than the predetermined threshold value, wherein when the supply of electric power is performed on permission from the switch unit, the notification unit is activated and notifies the state change of the monitoring target.
4 . The monitoring device according to claim 3 , further comprising a holding unit that holds, for a predetermined time period, a state of permitting the supply of electric power by the switch unit and then switches the switch unit to a shutting state when the voltage value of the power generation being greater than or equal to the predetermined threshold value becomes a value less than the predetermined threshold value.
5 . The monitoring device according to claim 3 , comprising a plurality of the vibration-driven energy harvesting units, wherein the switch unit permits the supply of electric power when at least one of voltage values of the plurality of the vibration-driven energy harvesting units is greater than or equal to the predetermined threshold value, and shuts off the supply of electric power when all of the voltage values of the plurality of the vibration-driven energy harvesting units are less than the predetermined threshold value.
6 . The monitoring device according to claim 5 , wherein each of the plurality of the vibration-driven energy harvesting units has a different natural frequency from one another.
7 . The monitoring device according to any one of claim 3 , wherein the monitoring target is a transformer, and a natural frequency of the vibration-driven energy harvesting unit is set to a frequency of a partial discharge of the transformer.
8 . The monitoring device according to claim 1 , further comprising: a power supply for operating the notification unit; and wherein the switch unit is configured to permit supply of electric power from the power supply to the notification unit when the voltage value of the power generation is greater than or equal to the predetermined threshold value and that shuts off the supply of electric power from the power supply to the notification unit when the voltage value of the power generation is less than the predetermined threshold value, wherein the notification unit is activated by the supply of electric power to notify normality in the monitoring target and stops notifying the normality by shutting off the supply of electric power to notify an anomaly in the monitoring target.
9 . The monitoring device according to claim 1 , further comprising: a power supply for operating the notification unit; and wherein the switch unit is configured to shut off supply of electric power from the power supply to the notification unit when the voltage value of the power generation is greater than or equal to the predetermined threshold value and that permits the supply of electric power from the power supply to the notification unit when the voltage value of the power generation is less than the predetermined threshold value, wherein when the supply of electric power is performed on permission from the switch unit, the notification unit is activated and notifies the state change of the monitoring target.
10 . The monitoring device according to claim 1 , further comprising: a power supply for operating the notification unit; and wherein the switch unit is configured to shut off supply of electric power from the power supply to the notification unit when the voltage value of the power generation is greater than or equal to the predetermined threshold value and that permits the supply of electric power from the power supply to the notification unit when the voltage value of the power generation is less than the predetermined threshold value, wherein the notification unit is activated by the supply of electric power to notify normality in the monitoring target and stops notifying the normality by shutting off the supply of electric power to notify an anomaly in the monitoring target.
11 . The monitoring device according to claim 1 , wherein the notification unit transmits a wireless signal to notify the state change to an external device.
12 . The monitoring device according to claim 3 , further comprising an electricity storage unit that is charged by the power generation by the vibration-driven energy harvesting unit, the electricity storage unit being set to have a voltage value greater than or equal to the predetermined threshold value by electric power generated by a vibration that has an acceleration with a certain value or more and continues for a certain time period.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is the United States national phase of International Application No. PCT/JP2022/014182 filed Mar. 24, 2022, and claims priority to Japanese Patent Application No. 2021-072721 filed Apr. 22, 2021, Japanese Patent Application No. 2021-116338 and Japanese Patent Application No. 2022-043152 filed Mar. 17, 2022, filed Jul. 14, 2021, the disclosures of which are hereby incorporated by reference in their entireties. BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a monitoring device. Description of Related Art Conventionally, there have been known anomaly diagnosis apparatuses for a machine and equipment that identify the presence or absence or a sign of an anomaly in a rotary component such as a railroad vehicle and a wind turbine for power generation or identify the location of the anomaly (see Japanese Patent Laid-Open No. 2006-234784). In an anomaly diagnosis apparatus described in Japanese Patent Laid-Open No. 2006-234784, a sensor detects a vibration of a rolling bearing, and a signal processing unit takes in an electric signal from the sensor and analyzes a state of the vibration. The signal processing unit performs a frequency analysis of a waveform of the electric signal, a comparison between a frequency component in measured spectrum data obtained by the frequency analysis and a frequency component attributable to the component, and determination of the presence or absence of an anomaly in the component and the location of the anomaly based on a result of the comparison, and the like. SUMMARY OF THE INVENTION Technical Problem In the anomaly diagnosis apparatus described above, a vibration sensor, an acoustic emission (AE) sensor, an ultrasonic sensor, or the like is used as the sensor that is used to detect the vibration. The sensor requires supply of electric power thereto, and a high electric power is consumed by the signal processing unit that performs signal processing and the determination of the presence or absence and the location of an anomaly and the like. This raises a problem in that the anomaly diagnosis apparatus is not practical for continuously monitoring the determination of the presence or absence of an anomaly in a component because a frequency of battery replacement increases. Solution to Problem A monitoring device according to an aspect of the present invention includes a vibration-driven energy harvesting unit that performs power generation in response to a sound or a vibration being occurred by a monitoring target and having a predetermined frequency, and a notification unit that notifies a state change of the monitoring target based on a magnitude relationship between a predetermined threshold value and a voltage value of the power generation by the vibration-driven energy harvesting unit. Advantageous Effect of Invention According to the present invention, the vibration-driven energy harvesting unit functions as a sensor unit that catches a sound or a vibration. Therefore, no power supply is needed for the sensor unit, allowing power saving for the monitoring device. BRIEF DESCRIPTION OF THE DRAWINGS The terms FIG., FIGS., FIGURE, and Figures are used interchangeably in the specification to refer to the corresponding figures in the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of a monitoring device. FIG. 2 is a diagram illustrating Modification 1. FIG. 3 is a diagram illustrating Modification 2. FIG. 4 is a diagram illustrating a relation between frequencies f1 to f5 of abnormal sounds and natural frequencies fa to fc of vibration-driven energy harvesting elements. FIG. 5 is a diagram illustrating Modification 3. FIG. 6 is a diagram illustrating an application example of the monitoring device. DESCRIPTION OF THE INVENTION An embodiment for implementing the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of a monitoring device 1 in the present embodiment. The monitoring device 1 includes a vibration-driven energy harvesting element 10, a rectification/electricity storage unit 20, a switch circuit 30, a self-holding circuit 40, a turn-off circuit 50, a battery 60, and a notification unit 70 that operates on the battery 60 as a power supply. The vibration-driven energy harvesting element 10 includes a fixed comb electrode 101 and a movable comb electrode 102 that is supported by an elastic support part 103. The movable comb electrode 102 is caused to vibrate with respect to the fixed comb electrode 101 by a sound or a vibration that is a monitoring target, thus generating electric power. A natural frequency of the vibration-driven energy harvesting element 10 is set to a frequency of the sound or the vibration being the monitoring target. The vibration-driven energy harvesting element 10 is thus configured such that the movable comb electrode resonates with the sound or t