CN110954260B - Gasket type pressure sensor for detecting bolt pretightening force - Google Patents
Gasket type pressure sensor for detecting bolt pretightening force Download PDFInfo
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- CN110954260B CN110954260B CN201911185795.7A CN201911185795A CN110954260B CN 110954260 B CN110954260 B CN 110954260B CN 201911185795 A CN201911185795 A CN 201911185795A CN 110954260 B CN110954260 B CN 110954260B
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- elastic body
- polar plate
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- upper cover
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/24—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed
- G01L5/243—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed using washers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
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Abstract
The invention relates to a gasket type pressure sensor for detecting bolt pretightening force, which comprises an upper cover and a shell, wherein the upper cover is embedded in the top of the shell, a first elastic body, an upper polar plate and a second elastic body are sequentially arranged between the upper cover and the shell, second round holes with the same size are respectively formed in the center positions of the first elastic body, the upper polar plate and the second elastic body, the upper polar plate is connected with an alternating current measuring instrument for measuring capacitance values, the upper cover and the shell jointly form a lower polar plate, the upper polar plate is not in contact with the lower polar plate, when the first elastic body and/or the second elastic body is pressed and deformed, the distance between the upper polar plate and the lower polar plate is changed, so that the capacitance value generated between the upper polar plate and the lower polar plate is changed, and the bolt pretightening force is detected according to the change of the capacitance value. Compared with the prior art, the invention utilizes the elastomer and the parallel plate capacitor as the basic force-electricity conversion structure and combines an alternating current measuring instrument, thereby being capable of accurately detecting the pretightening force of the bolt in real time.
Description
Technical Field
The invention relates to the technical field of pressure sensors, in particular to a gasket type pressure sensor for detecting bolt pretightening force.
Background
High-strength bolts are widely applied to the industrial fields of civil construction, mechanical installation and the like, the pretightening force of the high-strength bolts usually reaches tens of tons or even twenty tons, and the load is huge, so that the safety requirement on fastening joints is high, and when the bolts are used as fastening pieces at key positions, the axial stress of the bolts, namely the pretightening force of the bolts, is usually required to be accurately detected and controlled so as to ensure the safety and the reliability of the connection.
The traditional bolt pretightening force measuring method comprises a torque wrench and an ultrasonic force measuring method, wherein the axial force measured by the torque wrench is unreliable, and firstly, the torque wrench needs to be regularly checked and maintained, and secondly, the torque wrench is easily influenced by other factors in practical application; the ultrasonic detection of the axial stress of the bolt has great limitation, and is not suitable for the conditions of vacuum environment, high-temperature environment and complex mechanical structure, so that the bolt pretightening force is usually detected by using a bolt monitoring sensor at present, but when the existing bolt detection sensor is applied to the pretightening force condition of a high-strength bolt up to dozens of tons, the measurement precision is low, the real-time detection is difficult to realize, the abnormal condition of the pretightening force of the bolt cannot be timely found, and the safety accident is easily caused.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a gasket type pressure sensor capable of detecting the pretightening force of a bolt in real time.
The purpose of the invention can be realized by the following technical scheme: a gasket type pressure sensor for detecting bolt pretightening force comprises an upper cover and a shell, wherein the upper cover is embedded in the top of the shell, first round holes with the same size are respectively formed in the central position of the upper cover and the central position of the bottom of the shell, a first elastic body, an upper polar plate and a second elastic body are sequentially arranged between the upper cover and the shell, second round holes with the same size are respectively formed in the central positions of the first elastic body, the upper polar plate and the second elastic body, the upper polar plate is connected with an alternating current measuring instrument for measuring capacitance values, the upper cover and the shell jointly form a lower polar plate, the upper polar plate and the lower polar plate are not in contact, when the first elastic body and/or the second elastic body are pressed and deformed, the distance between the upper polar plate and the lower polar plate is changed, so that the capacitance value generated between the upper polar plate and the lower polar plate is changed, and detecting the bolt pretightening force according to the change of the capacitance value.
Furthermore, the diameter of the second round hole is larger than that of the first round hole, an inner ring for guiding and positioning is sleeved in the first round hole, and an isolating ring for insulation is sleeved between the inner ring and the second round hole so as to ensure that the upper pole plate and the inner ring are not in contact conduction.
Further, the first elastic body covers the upper portion of the upper pole plate and wraps the side face of the upper pole plate, the top of the first elastic body is abutted to the bottom of the upper cover, the bottom of the second elastic body is abutted to the inner bottom face of the shell, the thickness of one side, close to the isolating ring, of the first elastic body is the same as that of the second elastic body, and therefore the linear change of the first elastic body and the linear change of the second elastic body in the compression direction are the same.
Further, the outer diameters of the first elastic body and the second elastic body are smaller than the inner diameter of the shell, so that the space allowance of the first elastic body and/or the second elastic body in compression deformation is ensured.
Furthermore, a threaded through hole is formed in the outer side of the shell, the axis of the threaded through hole is flush with the axial center face of the upper polar plate, a signal connector is installed in the threaded through hole, and a signal wire used for connecting the upper polar plate and the alternating current measuring instrument is arranged in the signal connector.
Further, the side of the upper plate is provided with a plane structure for connecting signal wires, so that the reliability of connection compaction is guaranteed.
Furthermore, the upper cover, the shell and the upper polar plate are made of carbon steel materials.
Further, the first elastomer and the second elastomer both adopt Ultem plus glass fiber reinforced materials.
Further, the isolating ring is made of rubber materials.
Further, the alternating current measuring instrument is an alternating current bridge.
Compared with the prior art, the invention has the following advantages:
firstly, the invention adopts a way of measuring capacitance in real time to detect the pretightening force of the bolt in real time, changes the pretightening force into the change of the capacitance value by arranging the first elastic body and the second elastic body and combining the capacitance formed between the upper polar plate and the lower polar plate, and the force-electricity conversion is directly stable.
In addition, the upper cover and the shell form the lower polar plate, and the upper polar plate is arranged between the upper cover and the shell, so that a double-layer symmetrical parallel capacitor structure is formed, the total capacitance is increased, and the measurement accuracy can be further effectively improved.
The invention adopts the signal connector, can be used for the alternating current measuring instrument to measure and monitor the capacitance in real time, the upper cover and the shell are jointly used as the lower polar plate to be connected with the ground, and the upper polar plate can normally receive alternating current or pulse signals transmitted by the signal connector to finish reliable and accurate measurement of the capacitance, thereby timely detecting the abnormal condition of the bolt pretightening force and ensuring the engineering safety.
Drawings
FIG. 1 is a schematic external view of the present invention;
FIG. 2 is a schematic cross-sectional view of the internal structure of the present invention;
FIG. 3 is a schematic view of the present invention with the structure broken away;
FIG. 4 is a schematic diagram illustrating the actual installation effect of the present invention in the embodiment;
the notation in the figure is: 1. the device comprises an upper cover, 2, a shell, 3, an upper polar plate, 4, a first elastic body, 5, a second elastic body, 6, a separating ring, 7, an inner ring, 8 and a signal joint.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments.
As shown in fig. 1 to 3, a gasket-type pressure sensor for detecting bolt pretension includes an upper cover 1, a housing 2, an upper plate 3, a first elastic body 4, a second elastic body 5, a spacer ring 6, an inner ring 7, and a signal connector 8.
The upper cover 1 is embedded in the top of the shell 2, namely the outer diameter of the upper cover 1 is equal to the inner diameter of the shell 2, the diameters of the upper cover 1 and the shell 2 are matched, and the upper cover 1 and the shell 2 can be coated with an upper polar plate 3, a first elastic body 4 and a second elastic body 5 after being aligned with each other, the upper cover 1 and the shell 2 are made of carbon steel materials, a circuit can be grounded when the upper cover 1 and the shell 2 are connected with a fastening piece, and the upper cover 1 and the shell 2 jointly form a lower polar plate;
the outer side of the shell 2 is provided with a threaded through hole, the axis of the threaded through hole is aligned with the axial central plane of the upper polar plate 3 and is used for installing a signal connector 8, the outer ring thread of the signal connector 8 is installed in a matching way with the threaded through hole of the shell 2, the inner center of the signal connector 8 is provided with a signal wire insulated and separated from the outer ring, the signal wire is connected to the outer side surface of the upper polar plate 3 and is well compacted so as to ensure the conductivity, the upper polar plate 3 is flattened at one side surface to form a planar knot suitable for being connected and compacted so as to be connected with the signal wire, and the connection reliability is further ensured;
the first elastic body 4 and the second lower elastic body 5 are both made of Ultem and glass fiber reinforced materials, have moderate elastic modulus, can be used as good dielectric and elastic bodies, meet Hooke's law, and can keep the linear relation between the pressure at two ends and the deformation in the stress direction in a small range;
the first elastic body 4 surrounds the upper polar plate 3 at the outer side and is in contact with the lower polar plate, and the thicknesses of the first elastic body 4 and the second elastic body 5 in the axial projection area of the upper polar plate 3 are completely consistent, so that the linear changes of the first elastic body 4 and the second elastic body 5 in the compression direction are the same;
the upper polar plate 3 is made of a carbon steel sheet, the diameter of the upper polar plate is slightly smaller than the diameter of the inner sections of the upper cover 1 and the shell 2, and the upper polar plate is not contacted with the upper cover 1 and the shell 2;
the isolating ring 6 is arranged between the upper cover 1 and the shell 2, is made of a rubber material with low elastic modulus, has good insulating effect and ensures that the upper polar plate 3 and the inner ring 7 cannot be in contact conduction in use;
the inner ring 7 is made of carbon steel, and the outer side of the inner ring 7 is matched with the upper cover 1, the isolating ring 6 and the shell 2 in size and used for guiding and positioning;
in addition, the parts in axial contact in the whole structure are bonded by the adhesive, so that the structure is prevented from being separated when placed.
After the installation of the structure is completed, a standard instrument is needed to calibrate the pressure sensor, and when the pressure sensor is actually used, the specific installation process is as follows:
1. normally installing a high-strength bolt fastener, installing a flat gasket, and not installing a nut;
2. the gasket type pressure sensor is put in and clings to the flat gasket;
3. continuing to install the nut, fastening, finishing the installation of the fastener, and achieving the installation effect as shown in fig. 4;
4. and then, the signal connector 8 is connected with an external monitoring system through a signal wire (such as an antenna), the capacitance value between the upper polar plate 3 and the lower polar plate is obtained by using an alternating current measuring instrument, and a pressure value, namely the pretightening force of the high-strength bolt fastener, can be obtained through conversion according to a linear relation.
In summary, according to the gasket-type pressure sensor provided by the invention, the pressure at the two ends of the sensor is measured through the stress-strain relationship of the elastic material and the dielectric property of the dielectric material, and the capacitance data is obtained by the external ac measuring instrument. The invention can be used as a gasket to be directly installed in a high-strength bolt fastener, monitors the change of the pretightening force of the bolt in real time, ensures the safety and reliability of bolt connection in a high-pressure state, and can be used in large projects such as high-load engineering projects of building buildings, large engineering machinery and the like. When the high-strength bolt fastening piece is used, the high-strength bolt fastening piece is sleeved with the high-strength bolt fastening piece, the signal connector is connected with the alternating-current measuring instrument, when the fastening piece is under the action of normal pretightening force, the capacitance is at a normal value, when the pressure at two ends of the sensor is reduced, the capacitance is reduced, if the pressure is lower than a set value, the fastening piece is damaged or deformed, the high-strength bolt fastening piece can be timely processed, and the overall engineering safety is ensured.
Claims (4)
1. A gasket type pressure sensor for detecting bolt pretightening force is characterized by comprising an upper cover (1) and a shell (2), wherein the upper cover (1) is embedded in the top of the shell (2), first round holes with the same size are respectively formed in the central position of the upper cover (1) and the central position of the bottom of the shell (2), a first elastic body (4), an upper polar plate (3) and a second elastic body (5) are sequentially arranged between the upper cover (1) and the shell (2), second round holes with the same size are respectively formed in the central positions of the first elastic body (4), the upper polar plate (3) and the second elastic body (5), the upper polar plate (3) is connected with an alternating current measuring instrument for measuring capacitance values, the upper cover (1) and the shell (2) jointly form a lower polar plate, and no contact exists between the upper polar plate (3) and the lower polar plate, when the first elastic body (4) and/or the second elastic body (5) is pressed to deform, the distance between the upper polar plate (3) and the lower polar plate changes, so that the capacitance value generated between the upper polar plate (3) and the lower polar plate changes, and the bolt pretightening force is detected according to the change of the capacitance value;
the diameter of the second round hole is larger than that of the first round hole, an inner ring (7) for guiding and positioning is sleeved in the first round hole, and an isolating ring (6) for insulation is sleeved between the inner ring (7) and the second round hole so as to ensure that the upper polar plate (3) and the inner ring (7) cannot be in contact conduction;
the first elastic body (4) covers the upper portion of the upper pole plate (3) and wraps the side face of the upper pole plate (3), the top of the first elastic body (4) is abutted to the bottom of the upper cover (1), the bottom of the second elastic body (5) is abutted to the inner bottom face of the shell (2), and the thickness of one side, close to the isolating ring (6), of the first elastic body (4) is the same as that of the second elastic body (5) so as to ensure that the linear changes of the first elastic body (4) and the second elastic body (5) in the compression direction are the same;
the outer diameters of the first elastic body (4) and the second elastic body (5) are smaller than the inner diameter of the shell (2) so as to ensure the space allowance of the compression deformation of the first elastic body (4) and/or the second elastic body (5);
the upper cover (1), the shell (2) and the upper polar plate (3) are made of carbon steel materials, and the first elastic body (4) and the second elastic body (5) are made of Ultem and glass fiber reinforced materials;
the measuring device is characterized in that a threaded through hole is formed in the outer side of the shell (2), the axis of the threaded through hole is flush with the axial center face of the upper pole plate (3), a signal connector (8) is installed in the threaded through hole, a signal wire used for connecting the upper pole plate (3) with an alternating current measuring instrument is arranged in the signal connector (8), the signal connector (8) can be used for the alternating current measuring instrument to measure and monitor capacitance in real time, the upper cover (1) and the shell (2) are jointly used as a lower pole plate to be connected with the ground, and the upper pole plate (3) can normally receive alternating current or pulse signals transmitted from the signal connector (8) so as to complete reliable and accurate measurement of the capacitance.
2. The gasket-type pressure sensor for detecting bolt pretension according to claim 1, wherein the side surface of the upper plate is provided with a planar structure for connecting signal lines to ensure the reliability of connection and compaction.
3. Gasket-type pressure sensor for detecting bolt pretension according to claim 1, characterized in that the spacer ring (6) is made of rubber material.
4. The gasket-type pressure sensor for detecting bolt pretension according to claim 1, wherein said ac measuring instrument is an ac bridge.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911185795.7A CN110954260B (en) | 2019-11-27 | 2019-11-27 | Gasket type pressure sensor for detecting bolt pretightening force |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911185795.7A CN110954260B (en) | 2019-11-27 | 2019-11-27 | Gasket type pressure sensor for detecting bolt pretightening force |
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| CN110954260A CN110954260A (en) | 2020-04-03 |
| CN110954260B true CN110954260B (en) | 2022-04-05 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP7497221B2 (en) * | 2020-06-09 | 2024-06-10 | パラマウントベッド株式会社 | Mattress, sensor system |
| CN112326090A (en) * | 2020-10-28 | 2021-02-05 | 西安工程大学 | Real-time not hard up degree monitoring devices of transmission tower bolt |
| CN112924073B (en) * | 2021-01-29 | 2022-04-05 | 同济大学 | Strain type bolt pretightening force gasket sensor based on cantilever structure increase deformation |
| CN112924074A (en) * | 2021-01-29 | 2021-06-08 | 同济大学 | Fan-shaped differential capacitance type gasket type pressure sensor |
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| CN209014180U (en) * | 2018-11-13 | 2019-06-21 | 上海明华电力技术工程有限公司 | Pitch variable bearings attachment bolt load-bearing monitor device |
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