Wireless measurement of pre-tightening force in fasteners and method of manufacture

Abstract

The application provides a fastener for wireless measurement of pre-tightening force and a manufacturing method. The fastener comprises a piezoelectric layer, an insulating layer and an electrode layer which are connected to a fastener base in sequence. The insulating layer is provided with a detection induction coil which is insulated from the piezoelectric layer. The electrode layer comprises a conductive part one and a conductive part two which is insulated from the conductive part one. One end of the detection induction coil is connected to the conductive part one, and the other end of the detection induction coil is connected to the conductive part two and the piezoelectric layer. The application has the beneficial effect that the wireless measurement of pre-tightening force can be realized through the cooperation of the receiving coil and the detection induction coil, the testing process is simple, and the pre-tightening force testing efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of measuring pre-tightening force, in particular to a fastener for wireless measurement of pre-tightening force and a manufacturing method thereof. BACKGROUND

[0002] Bolts are commonly used parts for connecting structures, which have the characteristics of simple structure, convenient installation, easy disassembly, high connection strength and good reliability. With the increasing requirements for the working performance and safety and reliability of structures, Germany has developed a technology for measuring pre-tightening force by using ultrasonic waves. By preparing a permanent piezoelectric film sensor on the bolt, then using the inverse piezoelectric effect of the sensor to generate ultrasonic signals in the bolt, and according to the relationship between different loads, temperatures and the time difference of ultrasonic waves flying in the bolt, the load in the bolt is measured, which is a direct and in-situ measurement method for bolt load. The intelligent bolt with a permanent piezoelectric film sensor is a terminal product covering the entire life cycle of the bolt, which can detect the pre-tightening force of the bolt in-situ and online. Around 2008, it was gradually adopted by the high-end products of the European and American industries, mainly applied in the industries of aviation, aerospace and the like. However, the technology still needs to use a wired way to connect the intelligent fastener with the measurement system and transmit signals in the process of use, which is complicated in operation and low in testing efficiency, and is difficult to be applied on a large scale. SUMMARY

[0003] Therefore, the present application aims to provide a fastener for wireless measurement of pre-tightening force and a manufacturing method thereof, so as to solve at least one of the above technical problems.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] In one aspect, the present application provides a fastener for wireless measurement of pre-tightening force, which comprises a piezoelectric layer, an insulating layer and an electrode layer connected in sequence on a fastener base body, wherein the insulating layer is provided with a detection induction coil insulated from the piezoelectric layer, the electrode layer comprises a conductive part one and a conductive part two insulated from the conductive part one, one end of the detection induction coil is connected with the conductive part one, and the other end of the detection induction coil is connected with the conductive part two and the piezoelectric layer.

[0006] Further, the piezoelectric layer is a structural member made of piezoelectric crystal material;

[0007] Preferably, the piezoelectric layer is a structural member made of zinc oxide material;

[0008] Preferably, the piezoelectric layer is a structural member made of zinc oxide material;

[0009] Preferably, the piezoelectric layer is a structural member made of alpha-quartz material.

[0010] Further, the piezoelectric layer is a structure made of piezoelectric ceramic material.

[0011] Further, the detection induction coil is a spiral structure metal coil, one end of the detection induction coil near the center protrudes from the upper surface of the insulating layer and is connected with the conductive part one, and the other end of the detection induction coil away from the center protrudes from the upper surface of the insulating layer and is connected with the conductive part two.

[0012] Further, the electrode layer includes an insulating ring, the inner side of the insulating ring is the conductive part one, the outer side of the insulating ring is the guide part two, and the guide part two is connected with the edge of the piezoelectric layer.

[0013] Further, the insulating layer is a structure made of insulating material.

[0014] Preferably, the insulating layer is a structure made of silicon oxide material.

[0015] Preferably, the insulating layer is a structure made of plastic material.

[0016] Preferably, the insulating layer is a structure made of phosphate material.

[0017] Preferably, the insulating layer is a structure made of enamel material.

[0018] Further, the electrode layer is a structure made of conductive material.

[0019] Preferably, the electrode layer is a structure made of titanium material.

[0020] Preferably, the electrode layer is a structure made of zinc material.

[0021] Preferably, the electrode layer is a structure made of chromium material.

[0022] Another aspect of the present application provides a manufacturing method of the fastener for wireless measurement of pre-tightening force according to the above-mentioned aspect, comprising the following steps:

[0023] S1, using plating process to manufacture piezoelectric layer on the surface of the fastener base;

[0024] S2, using plating process to manufacture insulating layer on the surface of the piezoelectric layer;

[0025] S3, etching a groove matching the detection induction coil on the insulating layer;

[0026] S4, installing the detection induction coil in the groove, and bending the two ends of the detection induction coil upward to protrude from the upper surface of the insulating layer;

[0027] S5, using plating process to manufacture a sealed groove at the detection induction coil, so that the detection induction coil is located in the insulating layer except for the two ends;

[0028] S6, using plating process to make conductive part one and conductive part two which is insulated from conductive part one on the surface of the insulation layer, conductive part one is connected with one end of the detection induction coil, conductive part two is connected with the other end of the detection induction coil, and conductive part two is connected with the piezoelectric layer.

[0029] Further, before the step S1, the end face of the substrate to be plated is polished.

[0030] Further, before the step S6, an insulating ring is installed on the edge surface of the insulation layer before plating, and plating process is performed on the inner side and the outer side of the insulating ring to form the conductive part one and the conductive part two.

[0031] Compared with the prior art, the wireless pre-tightening force measuring fastener and the manufacturing method have the following beneficial effects:

[0032] (1) The wireless pre-tightening force measuring fastener can realize wireless measurement of pre-tightening force through the cooperation of the receiving coil and the detection induction coil, and the test process is simple, thereby improving the pre-tightening force test efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which form a part of the disclosure, are intended to provide further understanding of the present disclosure and are incorporated herein for explanation by way of the exemplary embodiments of the present disclosure and the explanation of the present disclosure. In the drawings:

[0034] Figure 1 The fastener structure diagram is described in the embodiments of the present disclosure.

[0035] Explanation of reference signs:

[0036] 1, fastener substrate; 2, piezoelectric layer; 3, detection induction coil; 4, insulation layer; 5, electrode layer. DETAILED DESCRIPTION

[0037] It should be noted that the embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0038] The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] Embodiment one:

[0040] As shown in the drawings, Figure 1 A wireless pre-tightening force measuring fastener includes a piezoelectric layer 2, an insulation layer 4, and an electrode layer 5 connected in sequence on a fastener substrate 1. The insulation layer 4 is provided with a detection induction coil 3 insulated from the piezoelectric layer 2. The electrode layer 5 includes a conductive part one and a conductive part two insulated from the conductive part one. One end of the detection induction coil 3 is connected with the conductive part one, and the other end of the detection induction coil 3 is connected with the piezoelectric layer 2 through the conductive part two.

[0041] Piezoelectric layer 2 is a structural component made of piezoelectric crystal material;

[0042] In some embodiments, the piezoelectric layer 2 is a structural component made of zinc oxide;

[0043] In other embodiments, the piezoelectric layer 2 is a structural component made of zinc oxide;

[0044] In other embodiments, the piezoelectric layer 2 is a structural component made of α-quartz material.

[0045] Piezoelectric layer 2 is a structural component made of piezoelectric ceramic material.

[0046] The detection induction coil 3 is a helical metal coil, with one end of the detection induction coil 3 near the center ( Figure 1 At point B, the upper surface of the protruding insulating layer 4 is connected to the conductive part, and the end of the detection induction coil 3 furthest from the center ( Figure 1 The upper surface of the protruding insulating layer 4 at point A is connected to the conductive part 2.

[0047] The electrode layer 5 includes an insulating ring, with a conductive part 1 inside the insulating ring and a guiding part 2 outside the insulating ring. The guiding part 2 is connected to the edge of the piezoelectric layer 2.

[0048] Insulation layer 4 is a structural component made of insulating material;

[0049] In some embodiments, the insulating layer 4 is a structural component made of silicon oxide;

[0050] In other embodiments, the insulating layer 4 is a structural component made of plastic;

[0051] In other embodiments, the insulating layer 4 is a phosphate material structural component;

[0052] In other embodiments, the insulating layer 4 is a structural component made of enamel.

[0053] Electrode layer 5 is a structural component made of conductive material;

[0054] In some embodiments, the electrode layer 5 is a structural component made of titanium.

[0055] In other embodiments, electrode layer 5 is a zinc-based structural component;

[0056] In other embodiments, the electrode layer 5 is a chromium-based structural component.

[0057] Work process:

[0058] In the implementation of the scheme, the transmitting coil and the receiving coil are arranged at the corresponding position of the detection induction coil 3. The magnetic flux of the detection induction coil 3 is changed by regularly changing the current in the transmitting coil, and a voltage is generated at the two ends of the detection induction coil 3. At this time, a potential difference is formed between the conductive part one and the conductive part two of the electrode layer 5, and the piezoelectric layer 2 is excited to emit ultrasonic waves in the fastener base body 1. When the ultrasonic waves return, a voltage difference is formed in the voltage layer, an electric current is generated in the detection induction coil 3, and the magnetic flux changes. The magnetic flux of the receiving coil changes, and the receiving coil generates an electric current. The difference between the time node of the output current of the transmitting coil and the time node of the induced current of the receiving coil can obtain the time of ultrasonic wave propagation.

[0059] The fastener base body 1 is a bolt. When the bolt is not installed, the measured acoustic time length is the basic acoustic time length. When the bolt is installed, the acoustic time changes under the action of stress and temperature. At this time, the measured acoustic time length is the pre-tightening acoustic time length. The time difference between the pre-tightening acoustic time length and the basic acoustic time length can be calculated. The bolt temperature after being loaded and the time difference can be obtained through the pre-tightening force measurement software to calculate the size of the pre-tightening force.

[0060] In view of the problem that the permanent piezoelectric film sensor intelligent bolt needs to be connected with the measurement system and signal transmission in a wired manner during use, a normal-temperature type intelligent fastener structure with a wireless measurement pre-tightening force function is proposed by combining a near-field wireless ultrasonic monitoring technology based on electromagnetic induction coupling. The method is simple to implement. The normal-temperature sensor with the wireless measurement pre-tightening force function is verified. The signal is stable and reliable, and has high practical application value.

[0061] The cooperation of the receiving coil and the detection induction coil 3 can realize wireless measurement of the pre-tightening force in centimeter level, and the test process is simple, which improves the pre-tightening force test efficiency.

[0062] Embodiment two:

[0063] A manufacturing method of a fastener for wireless measurement of pre-tightening force according to the above embodiment one, comprising the following steps:

[0064] S1, using plating process to manufacture piezoelectric layer 2 on the surface of fastener base body 1;

[0065] S2, using plating process to manufacture insulating layer 4 on the surface of piezoelectric layer 2;

[0066] S3, etching a groove matched with the detection induction coil 3 on the insulating layer 4;

[0067] S4, installing the detection induction coil 3 in the groove, and bending the two ends of the detection induction coil 3 upwards to protrude above the upper surface of the insulating layer 4;

[0068] S5, using a plating process to make a sealed groove at the detection induction coil 3, so that the detection induction coil 3 is located in the insulating layer 4 except for two ends;

[0069] S6, using a plating process to make a conductive part one and a conductive part two which is insulated from the conductive part one on the surface of the insulating layer 4, the conductive part one is connected with one end of the detection induction coil 3, the conductive part two is connected with the other end of the detection induction coil 3, and the conductive part two is connected with the piezoelectric layer 2.

[0070] Before step S1, the end face of the substrate to be plated is polished.

[0071] Before plating in step S6, an insulating ring is installed on the edge surface of the insulating layer 4, and the plating process is performed on the inner side and the outer side of the insulating ring to form the conductive part one and the conductive part two.

[0072] Those skilled in the art can understand that the units and method steps of the examples described in combination with the embodiments disclosed herein can be realized by electronic hardware, computer software or a combination of both. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0073] In several embodiments provided in the present application, it should be understood that the disclosed method and system can be implemented in other ways. For example, the division of the above-mentioned units is only a logical functional division, and actual implementation can have another division manner, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. The above-mentioned units can be or can not be physically separated, and the components displayed as units can be or can not be physical units, i.e. they can be located in one place or distributed on multiple network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment of the present application.

[0074] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and description of the present application.

[0075] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for manufacturing a fastener with wireless preload measurement, characterized in that, The fastener is implemented by wirelessly measuring the preload force. The fastener includes a piezoelectric layer (2), an insulating layer (4), and an electrode layer (5) connected in sequence to the fastener base (1). The insulating layer (4) is provided with a detection coil (3) that is insulated from the piezoelectric layer (2). The electrode layer (5) includes a first conductive part and a second conductive part that is insulated from the first conductive part. One end of the detection coil (3) is connected to the first conductive part, and the other end of the detection coil (3) is connected to the second conductive part and the piezoelectric layer (2). The detection induction coil (3) is a spiral metal coil. One end of the detection induction coil (3) near the center protrudes from the upper surface of the insulating layer (4) and is connected to the first conductive part. The other end of the detection induction coil (3) away from the center protrudes from the upper surface of the insulating layer (4) and is connected to the second conductive part. The electrode layer (5) includes an insulating ring, the inner side of which is a conductive part one, and the outer side of which is a conductive part two. The conductive part two is connected to the edge of the piezoelectric layer (2). The production method includes the following steps: S1. A piezoelectric layer (2) is fabricated on the surface of the fastener substrate (1) using a plating process; S2. An insulating layer (4) is formed on the surface of the piezoelectric layer (2) using a plating process; S3. A groove matching the detection induction coil (3) is etched into the insulating layer (4); S4. Install the detection induction coil (3) in the groove, and bend both ends of the detection induction coil (3) upwards to protrude from the upper surface of the insulating layer (4); S5. A sealing groove is made at the detection induction coil (3) using a plating process, so that the detection induction coil (3) is located inside the insulating layer (4) except for the two ends. S6. Conductive part 1 and conductive part 2, which are insulated from conductive part 1, are made on the surface of insulating layer (4) using a plating process. Conductive part 1 is connected to one end of detection induction coil (3), conductive part 2 is connected to the other end of detection induction coil (3), and conductive part 2 is connected to piezoelectric layer (2).

2. The method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: Before step S1, the end face of the substrate to be plated is ground and polished.

3. The method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: Before plating in step S6, an insulating ring is installed on the edge of the insulating layer (4), and a plating process is performed on the inner and outer sides of the insulating ring to form conductive part one and conductive part two.

4. The method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The piezoelectric layer (2) is a structural component made of piezoelectric crystal material.

5. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The piezoelectric layer (2) is a structural component made of zinc oxide.

6. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The piezoelectric layer (2) is a structural component made of α-quartz material.

7. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The piezoelectric layer (2) is a structural component made of piezoelectric ceramic material.

8. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The insulating layer (4) is a structural component made of insulating material.

9. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The insulating layer (4) is a structural component made of silicon oxide.

10. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The insulating layer (4) is a structural component made of plastic.

11. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The insulating layer (4) is a structural component made of phosphate material.

12. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The insulating layer (4) is a structural component made of enamel.

13. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The electrode layer (5) is a structural component made of conductive material.

14. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The electrode layer (5) is a structural component made of titanium.

15. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The electrode layer (5) is a zinc-based structural component.

16. A method for manufacturing a fastener with wireless preload measurement according to claim 1, characterized in that: The electrode layer (5) is a chromium-based structural component.

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