CN213936233U - A piezoelectric fiber intelligence gasket for monitoring of bolt is not hard up - Google Patents
A piezoelectric fiber intelligence gasket for monitoring of bolt is not hard up Download PDFInfo
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- CN213936233U CN213936233U CN202022549669.XU CN202022549669U CN213936233U CN 213936233 U CN213936233 U CN 213936233U CN 202022549669 U CN202022549669 U CN 202022549669U CN 213936233 U CN213936233 U CN 213936233U
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- 239000000835 fiber Substances 0.000 title claims abstract description 73
- 238000012544 monitoring process Methods 0.000 title claims abstract description 28
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
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- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
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Abstract
The utility model discloses a piezoelectric fiber intelligence gasket for monitoring of bolt looseness. The intelligent gasket comprises a gasket and a piezoelectric fiber sensor, wherein the gasket is formed by meshing a step-shaped upper gasket and a step-shaped lower gasket, a U-shaped groove is formed in the circumferential direction, the piezoelectric fiber sensor is of an annular structure, is arranged at the U-shaped groove formed by the upper gasket and the lower gasket, and consists of a sensitive element and epoxy resin; the intelligent gasket senses the pre-tightening force of the bolt by using the piezoelectric fiber sensor, monitors the change fluctuation of an output signal, judges the loosening or failure condition of the bolt and realizes the real-time monitoring of the connection state of the bolt; the sensing element of the intelligent gasket is formed by connecting a plurality of annular arrays of piezoelectric fibers in parallel, can uniformly sense the variation of pretightening force acting on the gasket, has high sensitivity, is suitable for various bolt connecting pieces, can bear certain impact load, can be used for monitoring the bolt state under severe working conditions, and has wide application market.
Description
Technical Field
The utility model belongs to the technical field of bolted connection state monitoring, a piezoelectric fiber intelligence gasket that is used for the monitoring of bolt looseness is used for real-time supervision bolted connection state is provided.
Background
The bolt connection is widely applied to various industries such as machinery, traffic, electric power, civil engineering and the like as a connection mode for connecting detachable components and transferring load, and the connection state directly influences whether the whole structure or equipment can normally work or not, so that the reliability and the safety of the whole structure or equipment are concerned. Under the environment of impact and forced vibration of long-term work or cyclic load, the bolt often appears the condition such as becoming flexible or losing efficacy, leads to equipment life-span to descend, even causes serious incident and serious property loss. And for bolts working in severe environment and complex working conditions, the tightness and failure of the bolts are more difficult to directly judge. In order to avoid catastrophic results caused by bolts with a connection state not meeting normal requirements, the bolt connection state real-time online monitoring is particularly important.
Common bolt fastening force testing methods include a torque pulling method, a resistance strain gauge electrical testing method, a photometric mechanical method and the like, but the testing methods generally have the defects of low efficiency, inaccurate precision, limitation of bolt installation forms, difficulty in realization of a plurality of working occasions and the like. The existing bolt connection state detection technology adopting a piezoelectric material active sensing mode is favored by researchers due to the advantages of fast dynamic response, high detection precision, high sensitivity, wide application range, convenience in use and the like. The working principle of the sensor is that the piezoelectric property of a piezoelectric fiber sensor arranged on a bolt connecting piece is utilized to sense physical quantities such as stress strain and the like, an electric signal is output, the relation between the signal energy loss and the bolt pretightening force is analyzed, and the bolt connecting state is judged.
The piezoelectric ceramic sensor is not impact-resistant, is easy to break and has unstable performance, so that the piezoelectric ceramic sensor is difficult to be used in the environment of impact of cyclic load and forced vibration for a long time. The common flexible piezoelectric sensor in the market contains metal core piezoelectric fiber and MFC which are expensive, the preparation process is complex, and the PVDF piezoelectric performance is greatly influenced by the environmental temperature. The application publication number CN107355464A patent of the invention discloses a stacked piezoelectric ceramic intelligent gasket for monitoring bolt looseness, which does not solve the problems of large brittleness, high hardness, and impact and vibration resistance of the traditional piezoelectric ceramic element. The invention patent of application publication No. CN109632157A discloses that a PVDF piezoelectric film used in a bolt joint surface dynamic stress device is not suitable for an environment with severe working temperature.
Therefore, the patent describes a piezoelectric fiber intelligent gasket for monitoring bolt looseness, the intelligent gasket is designed to be meshed with a stepped upper gasket and a stepped lower gasket, a sensor is placed in a U-shaped groove formed by meshing, and the sensor is protected from being damaged by overlarge torque in the bolt pre-tightening process; the change of the stress-strain physical quantity between bolt connection interfaces is efficiently sensed by utilizing piezoelectric fibers with certain toughness and superior performance; a plurality of piezoelectric fiber annular arrays are adopted for parallel connection, so that the bolt connection state is uniformly sensed, and the output detection signal amplitude is improved; the epoxy resin serves as a protective layer and an insulating layer of the sensitive element, can bear certain impact load and vibration, is simple in preparation process, low in processing cost and strong in weather resistance, and is suitable for complex working conditions.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a main aim at provides a piezoelectric fiber intelligence gasket for monitoring of bolt looseness aims at real-time supervision bolted connection spare hookup state, utilizes piezoelectric sensor's piezoelectricity effect characteristic, and on external force loaded the piezoelectric sensor promptly, external force made piezoelectric sensor deformation, converts the mechanical energy of input into the signal of telecommunication through piezoelectric effect. Applying a certain amount of periodic excitation to the top of the bolt as calibration excitation, wherein at the moment, the piezoelectric fiber sensor in the intelligent gasket generates a certain deformation, and the sensed stress strain is converted into an electric signal by utilizing the piezoelectric effect characteristic of the piezoelectric fiber sensor; collecting an electric signal generated by a piezoelectric fiber sensor in the intelligent gasket, and taking the signal as a reference signal; and (3) applying calibration excitation at regular time, comparing the electric signals acquired in different time periods with the reference signals, monitoring the difference degree of the signals, judging the bolt connection state, performing real-time early warning, and timely screwing down the bolt or replacing the bolt.
In order to achieve the purpose, the technical scheme of the utility model: the intelligent piezoelectric fiber gasket for monitoring bolt looseness is characterized by comprising a gasket and a piezoelectric fiber sensor, wherein the gasket is formed by meshing a step-shaped upper gasket and a step-shaped lower gasket, a U-shaped groove is formed in the circumferential direction, the piezoelectric fiber sensor is of an annular structure, is arranged at the U-shaped groove formed by the upper gasket and the lower gasket, and consists of a sensitive element and epoxy resin.
Furthermore, the sensitive element comprises a plurality of piezoelectric fiber rods which are arranged radially and surround the circular array of the circle center, an inner electrode, an outer electrode and a wiring terminal; one end of the piezoelectric fiber rod is connected with the inner electrode, the other end of the piezoelectric fiber rod is connected with the outer electrode, and the piezoelectric fiber rods are arranged between the inner electrode and the outer electrode in parallel. The epoxy resin is used as a protective layer and upper and lower insulating layers of the sensitive element, and the sensitive element is packaged to form the annular piezoelectric fiber sensor.
Furthermore, a first stepped boss structure is circumferentially arranged in the through hole in the stepped lower gasket, the outer circular surface of the first stepped boss structure is in clearance fit with the through hole in the piezoelectric fiber sensor, a second stepped boss structure is circumferentially arranged in the through hole in the stepped upper gasket, and the first stepped boss structure and the second stepped boss structure are mutually meshed and assembled into a whole to form the intelligent gasket.
Further, the gasket material and the size are selected according to the monitored working condition of the bolt; the sensing element consists of an inner electrode and an outer electrode which are annularly arrayed piezoelectric fiber rods, the diameter of each piezoelectric fiber rod is about 3/5 times of the height of the U-shaped groove, and the height of the U-shaped groove is 1/3 times of the total height of the gasket. The sensitive element is positioned in the middle of the epoxy resin, the upper and lower heights of a packaging layer formed by the epoxy resin are uniformly distributed on the upper and lower surfaces of the piezoelectric fiber rod, and the overall thickness of the piezoelectric fiber sensor packaged by the epoxy resin is equal to or slightly larger than the height of the U-shaped groove; the epoxy resin is formed by mixing an adhesive A and an adhesive B, wherein the adhesive A is an epoxy resin adhesive, the adhesive B is a curing agent, and the cured epoxy resin has certain flexibility; the inner electrode, the outer electrode and the wiring terminal are made of red copper.
The application method of the piezoelectric fiber intelligent gasket for monitoring bolt looseness is characterized by comprising the following steps of:
aligning the connected workpiece mounting holes, inserting bolts into the mounting holes, mounting the intelligent gasket and the nuts, and screwing the threaded connecting piece by using a torque wrench until a pre-tightening force is set. Applying a certain amount of periodic excitation to the top of the bolt as calibration excitation, wherein at the moment, the piezoelectric fiber sensor in the intelligent gasket generates a certain deformation, and the sensed stress strain is converted into an electric signal by utilizing the piezoelectric effect characteristic of the piezoelectric fiber sensor; collecting electric signals (such as admittance signals or time domain signals and the like) generated by a piezoelectric fiber sensor in the intelligent gasket, and taking the signals as reference signals; and (3) applying calibration excitation at regular time, comparing electric signals (such as admittance signals or time domain signals) acquired in different time periods with reference signals, monitoring the difference degree of the signals, judging the bolt connection state, performing real-time early warning, and timely screwing or replacing the bolt.
The utility model has the advantages that:
(1) the utility model discloses can realize the real-time supervision to bolted connection state, utilize the stress strain physical quantity change between the high-efficient perception bolted connection interface of piezoelectric fiber sensor, the bolted connection state can be judged to the relation between analysis output signal and the bolt pretightning force, saves artifical detection cost, but remote monitoring bolted connection state does not receive external environment factor to disturb, reduces the risk of measurement personnel at high-risk environment work.
(2) This gasket intermeshing about this intelligence gasket design echelonment, the sensor is placed in the U-shaped groove department that the meshing formed, and the protection sensor is not destroyed by too big moment of torsion at bolt pretension in-process, need not to reform transform the bolt standard part, avoids reforming transform the bolt and causes bolted connection spare self performance to descend, and the gasket structural component of design is few, low in production cost, the general work occasion that is used for ordinary gasket.
(3) A plurality of piezoelectric fiber annular arrays are connected in parallel to form a sensitive element which can uniformly sense the connection state of the bolt, so that the amplitude of an output detection signal is improved, the result analysis is facilitated, and the monitoring and identifying precision is improved; the epoxy resin serves as a protective layer and an insulating layer of the sensitive element, can bear certain impact load and vibration, is suitable for complex working conditions, improves the weather resistance, does not need to design the insulating layer again, simplifies the manufacturing process and has low processing cost.
Drawings
Fig. 1 is a schematic diagram of a three-dimensional assembly of a piezoelectric fiber intelligent gasket for monitoring bolt loosening according to the present invention;
fig. 2 is an exploded view of the three-dimensional structure of the intelligent piezoelectric fiber gasket for monitoring bolt loosening according to the present invention;
FIG. 3 is a gasket assembly view of a piezoelectric fiber intelligent gasket for monitoring bolt loosening according to the present invention;
fig. 4 is the utility model relates to a sensing element structure chart of piezoelectric fiber intelligence gasket for monitoring of bolt looseness.
Fig. 5 is the utility model relates to a structural schematic diagram of a piezoelectric fiber intelligence gasket for monitoring of bolt looseness.
In the figure:
1- "ladder-shaped" upper gasket, 2-piezoelectric fiber sensor, 3- "ladder-shaped" lower gasket, 4-wiring terminal, 5-piezoelectric fiber stick, 6-inner electrode, 7-outer electrode, 8-epoxy resin, 10-U-shaped groove, 31-first ladder-shaped boss structure, 32-second ladder-shaped boss structure.
Detailed Description
As shown in fig. 1, 2 and 3, the piezoelectric fiber intelligent gasket for monitoring bolt loosening is characterized by comprising gaskets 1 and 3 and a piezoelectric fiber sensor 2, wherein the intelligent gasket is formed by meshing a step-shaped upper gasket 1 and a step-shaped lower gasket 3, a U-shaped groove 10 is formed in the circumferential direction, and the piezoelectric fiber sensor 2 is of an annular structure and is arranged at the U-shaped groove 10 formed by the upper and lower gaskets 1 and 3 and composed of a sensitive element and epoxy resin 8.
The sensing element shown in fig. 4 comprises a plurality of piezoelectric fiber rods 5 which are arranged radially and surround a circle center annular array, an inner electrode 6, an outer electrode and a connecting terminal 4; one end of the piezoelectric fiber rod 5 is connected with the inner electrode 6, the other end is connected with the outer electrode 7, and the piezoelectric fiber rods 5 are arranged in parallel between the inner electrode 6 and the outer electrode 7. The epoxy resin 8 is used as a protective layer and upper and lower insulating layers of the sensitive element, and the sensitive element is packaged to form the annular piezoelectric fiber sensor 2.
The 'ladder-shaped' lower gasket 3 is characterized in that a first ladder-shaped boss structure 31 is circumferentially arranged in a through hole, the outer circular surface of the first ladder-shaped boss structure 31 is in clearance fit with the through hole in the piezoelectric fiber sensor 2, a second ladder-shaped boss structure 32 is circumferentially arranged in the through hole in the 'ladder-shaped' upper gasket 1, and the first ladder-shaped boss structure 31 and the second ladder-shaped boss structure 32 are meshed with each other to be assembled into a whole to form the intelligent gasket.
Selecting the gasket material and the size according to the monitored working condition of the bolt; the sensing element consists of an annular array of piezoelectric fiber rods 5 and inner and outer electrodes 6 and 7, the diameter of the piezoelectric fiber rods 5 is about 3/5 times of the height of the U-shaped groove 10, and the height of the U-shaped groove 10 is 1/3 times of the total height of the gasket. The sensitive element is positioned in the middle of the epoxy resin 8, the upper height and the lower height of a packaging layer formed by the epoxy resin 8 are uniformly distributed on the upper surface and the lower surface of the piezoelectric fiber rod 5, and the whole thickness of the piezoelectric fiber sensor 2 packaged by the epoxy resin 8 is equal to or slightly greater than the height of the U-shaped groove 10; the epoxy resin 8 is formed by mixing an adhesive A and an adhesive B, the adhesive A is an epoxy resin adhesive, the adhesive B is a curing agent, and the cured epoxy resin 8 has certain flexibility; the inner electrode 6, the outer electrode 7 and the wiring terminal 4 are made of red copper.
The application method of the piezoelectric fiber intelligent gasket for monitoring bolt looseness is characterized by comprising the following steps of:
aligning the connected workpiece mounting holes, inserting bolts into the mounting holes, mounting the intelligent gasket and the nuts, and screwing the threaded connecting piece by using a torque wrench until a pre-tightening force is set. Applying a certain amount of periodic excitation to the top of the bolt as calibration excitation, wherein at the moment, the piezoelectric fiber sensor 2 in the intelligent gasket generates a certain deformation, and the sensed stress strain is converted into an electric signal by utilizing the piezoelectric effect characteristic of the piezoelectric fiber sensor; collecting electric signals (such as admittance signals or time domain signals and the like) generated by the piezoelectric fiber sensor 2 in the intelligent gasket, and taking the signals as reference signals; and (3) applying calibration excitation at regular time, comparing electric signals (such as admittance signals or time domain signals) acquired in different time periods with reference signals, monitoring the difference degree of the signals, judging the bolt connection state, performing real-time early warning, and timely screwing or replacing the bolt.
Claims (3)
1. The piezoelectric fiber intelligent gasket for monitoring bolt looseness is characterized by comprising a gasket and a piezoelectric fiber sensor; the gasket is formed by meshing a step-shaped upper gasket and a step-shaped lower gasket, a first step-shaped boss structure is arranged in the circumferential direction of a through hole in the step-shaped lower gasket, the outer circular surface of the first step-shaped boss structure is in clearance fit with a through hole in the piezoelectric fiber sensor, a second step-shaped boss structure is arranged in the circumferential direction of the through hole in the step-shaped upper gasket, the first step-shaped boss structure and the second step-shaped boss structure are mutually meshed and assembled into a whole, a U-shaped groove is formed in the circumferential direction of the upper gasket and the lower gasket, the piezoelectric fiber sensor is of an annular structure, is arranged at the U-shaped groove formed by the upper gasket and the lower gasket and is composed of a sensitive element and epoxy resin; the sensitive element comprises a piezoelectric fiber rod, an inner electrode, an outer electrode and a wiring terminal.
2. A piezoelectric fiber smart gasket for bolt loosening monitoring as claimed in claim 1, wherein: the piezoelectric fiber rods of the sensitive element are arranged in a plurality of radial directions and are arranged in an annular array around the circle center; one end of the piezoelectric fiber rod is connected with the inner electrode, the other end of the piezoelectric fiber rod is connected with the outer electrode, and the piezoelectric fiber rods are arranged between the inner electrode and the outer electrode in parallel; the epoxy resin is used as a protective layer and upper and lower insulating layers of the sensitive element, and the sensitive element is packaged to form the annular piezoelectric fiber sensor.
3. A piezoelectric fiber intelligent gasket for bolt looseness monitoring according to claim 1 or 2, wherein: selecting the size of the gasket according to the size of the monitored bolt; the diameter of the piezoelectric fiber rod of the sensing element is about 3/5 times of the height of the U-shaped groove, and the height of the U-shaped groove is 1/3 times of the total height of the gasket; the sensitive element is positioned in the middle of the epoxy resin, and the whole thickness of the piezoelectric fiber sensor is equal to or slightly greater than the height of the U-shaped groove; the outer electrode, the inner electrode and the wiring terminal are made of red copper.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022549669.XU CN213936233U (en) | 2020-11-06 | 2020-11-06 | A piezoelectric fiber intelligence gasket for monitoring of bolt is not hard up |
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| CN202022549669.XU CN213936233U (en) | 2020-11-06 | 2020-11-06 | A piezoelectric fiber intelligence gasket for monitoring of bolt is not hard up |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113739977A (en) * | 2021-08-24 | 2021-12-03 | 武汉珈联传感科技有限责任公司 | Intelligent gasket with piezoelectric sensor for bolt pretightening force test and preparation method of intelligent gasket |
| CN114166485A (en) * | 2021-11-22 | 2022-03-11 | 华电电力科学研究院有限公司 | On-line monitoring method for state of tower barrel bolt of wind turbine |
| CN114719888A (en) * | 2022-02-23 | 2022-07-08 | 瑞华智控电子科技(北京)有限公司 | Intelligent fan bolt online health monitoring system |
| CN114739560A (en) * | 2022-03-10 | 2022-07-12 | 深圳市风行太保科技有限公司 | Fastening device, threaded fastener monitoring method, device, system and storage medium |
| CN116952444A (en) * | 2023-09-20 | 2023-10-27 | 江天科技有限公司 | Intelligent bolt and nut gasket sensor |
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2020
- 2020-11-06 CN CN202022549669.XU patent/CN213936233U/en active Active
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113739977A (en) * | 2021-08-24 | 2021-12-03 | 武汉珈联传感科技有限责任公司 | Intelligent gasket with piezoelectric sensor for bolt pretightening force test and preparation method of intelligent gasket |
| CN113739977B (en) * | 2021-08-24 | 2023-12-19 | 武汉珈联传感科技有限责任公司 | Intelligent gasket with piezoelectric sensor for bolt pretightening force test and preparation method thereof |
| CN114166485A (en) * | 2021-11-22 | 2022-03-11 | 华电电力科学研究院有限公司 | On-line monitoring method for state of tower barrel bolt of wind turbine |
| CN114719888A (en) * | 2022-02-23 | 2022-07-08 | 瑞华智控电子科技(北京)有限公司 | Intelligent fan bolt online health monitoring system |
| CN114739560A (en) * | 2022-03-10 | 2022-07-12 | 深圳市风行太保科技有限公司 | Fastening device, threaded fastener monitoring method, device, system and storage medium |
| CN114739560B (en) * | 2022-03-10 | 2024-02-27 | 深圳市风行太保科技有限公司 | Fastening device, threaded fastener monitoring method, device, system and storage medium |
| CN116952444A (en) * | 2023-09-20 | 2023-10-27 | 江天科技有限公司 | Intelligent bolt and nut gasket sensor |
| CN116952444B (en) * | 2023-09-20 | 2023-12-12 | 江天科技有限公司 | Intelligent bolt and nut gasket sensor |
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