A device and method for measuring the tightening torque coefficient of a bolt fastener at -196 degrees celsius

Abstract

This application belongs to the technical field of bolt fastener tightening torque coefficient measurement in low-temperature environments, specifically relating to a device and method for measuring the bolt fastener tightening torque coefficient at -196℃. The device includes a low-temperature environment chamber, a bolt clamp, a nut tightening tool, and an axial force gauge. The low-temperature environment chamber has a liquid nitrogen injection hole. The bolt clamp is installed inside the chamber to clamp the head of the test bolt. One end of the nut tightening tool is located outside the chamber and is used to connect a tightening drive tool and its torque sensor; the other end extends into the chamber to hold the test nut and tighten it onto the bolt thread. The axial force gauge is fitted onto the outer circumference of the bolt thread to measure the preload between the bolt and the nut.

Description

Technical Field

[0001] This application belongs to the field of bolt fastener torque coefficient measurement technology under low temperature environment, specifically relating to a bolt fastener torque coefficient measurement device and method at -196℃. Background Technology

[0002] In superconducting, aerospace, nuclear power, cryogenic physics, and certain industries, equipment needs to be used in a cryogenic environment of -196°C (the boiling point of liquid nitrogen). Therefore, it is necessary to understand the relationship between the preload and torque of the bolts and fasteners of the fixed equipment in a cryogenic environment of -196°C, i.e., the torque coefficient, in order to facilitate design and application and prevent damage in cryogenic environments.

[0003] Currently, devices for measuring the torque coefficient of bolts and fasteners at -196℃ are typically complex in structure, cumbersome in operation, unreliable in application, and expensive, making it difficult to achieve rapid and accurate measurement of the torque coefficient of bolts and fasteners in a low-temperature environment of -196℃.

[0004] In view of the aforementioned technical deficiencies, this application is hereby filed. Summary of the Invention

[0005] The purpose of this application is to provide a device and method for measuring the torque coefficient of bolt fasteners at -196℃, for measuring the torque coefficient of bolt fasteners in a low-temperature environment of -196℃, so as to overcome or mitigate at least one of the known technical defects.

[0006] The technical solution of this application is:

[0007] A device for measuring the torque coefficient of bolt fasteners at -196℃ includes a low-temperature environment chamber, a bolt clamp, a nut tightening tool, and an axial force gauge;

[0008] A liquid nitrogen injection port is provided on the cryogenic environment chamber;

[0009] Bolt clamps are installed inside the low-temperature environment chamber to clamp the heads of the bolts on the test specimen;

[0010] One end of the nut tightening tool is located outside the low-temperature environment chamber and is used to connect the tightening drive tool and its torque sensor. The other end extends into the low-temperature environment chamber and is used to hold the test piece nut and tighten the test piece nut onto the thread of the test piece bolt.

[0011] Nut tightening tools include a sleeve and a water-circulating disc;

[0012] One end of the sleeve has a hexagonal boss located on the outside of the low-temperature environment chamber, which is used to connect the wrench drive tool and its torque sensor. The torque sensor is used to measure the tightening torque between the test piece bolts and the test piece nuts.

[0013] The other end of the sleeve has a hexagonal sleeve that extends into the low-temperature environment chamber through a through hole at the top of the chamber. It is used to hold the test piece nut and tighten the test piece nut onto the threaded rod of the test piece bolt.

[0014] The water circulation disc is fitted around the outer periphery of the sleeve rod. It has an annular cavity inside and is connected to the water source through the water circulation inlet and water circulation outlet opened on the side wall, so that circulating water can be introduced.

[0015] An axial force gauge is used to be fitted onto the outer circumference of the bolts and screws of the test piece to measure the preload between the bolts and nuts of the test piece.

[0016] According to at least one embodiment of this application, in the above-mentioned zero-196℃ bolt fastener tightening torque coefficient measuring device, the low-temperature environment chamber is a double-layer hollow structure chamber made of stainless steel or transparent material, and the vacuum is drawn through the air extraction hole opened on the side wall between the two layers, and the air extraction hole is sealed after vacuuming.

[0017] The upper part of the cryogenic environment chamber has a removable cover, and a liquid nitrogen injection hole is opened on the removable cover. Liquid nitrogen is filled into the cryogenic environment chamber through the liquid nitrogen injection hole to create the required cryogenic environment, and then the liquid nitrogen injection hole is sealed.

[0018] According to at least one embodiment of this application, in the above-mentioned device for measuring the torque coefficient of bolt fasteners at -196°C, the bolt clamp includes a support platform, a fixed platform, a clamping plate, and a clamping plate bolt.

[0019] The support platform is placed at the bottom of the low-temperature environment chamber;

[0020] The fixed platform is connected to the support platform and has a hexagonal groove on the top, in which the head of the test piece bolt is inverted.

[0021] There are six clamping plates, which are set in a hexagonal groove and are parallel to the six side walls of the hexagonal groove;

[0022] There are six clamping bolts, which are threaded onto the six side walls of the hexagonal groove. The six clamping plates are pressed against the six edges of the test piece bolt head to clamp the test piece bolt head.

[0023] According to at least one embodiment of this application, in the above-described measuring device for the torque coefficient of bolt fasteners at -196°C, the bottom of the fixed platform has a hexagonal connection, which is bolted to the surface of the support platform.

[0024] According to at least one embodiment of this application, in the above-mentioned bolt fastener tightening torque coefficient measuring device at -196°C, the wrench driving tool is a computer-controlled servo motor driver + servo motor + reducer drive mechanism, or a manual torque wrench configured with electronic signal output.

[0025] According to at least one embodiment of this application, in the above-mentioned measuring device for the torque coefficient of bolt fasteners at -196°C, a washer is provided between the axial force gauge and the bolt head of the test piece, and a washer and a sleeve are provided between the axial force gauge and the nut of the test piece.

[0026] According to at least one embodiment of this application, in the above-mentioned -196°C bolt fastener tightening torque coefficient measuring device, the torque sensor and axial force gauge are connected to a high-speed data acquisition system to collect and record data.

[0027] Multiple sets of thermocouples or platinum resistance temperature sensors are attached or clamped inside the test specimen bolts, test specimen nuts, and low-temperature environment chamber, and connected to a high-speed data acquisition system to collect and record data.

[0028] A method for measuring the tightening torque coefficient of bolts and fasteners at -196℃, implemented based on the aforementioned device for measuring the tightening torque coefficient of bolts and fasteners at -196℃, includes:

[0029] Liquid nitrogen was introduced into the cryogenic environment chamber. After the temperature inside the chamber stabilized at -196°C, the tightening torque coefficient of the bolts was measured.

[0030] Tighten the test piece nut onto the test piece bolt shank. During the tightening process, collect the torque and preload between the test piece bolt and the test piece nut, and calculate the torque coefficient. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the bolt fastener tightening torque coefficient measuring device at -196℃ provided in the embodiments of this application;

[0032] Figure 2 This is a schematic diagram of the bolt clamp providing an embodiment of this application clamping the bolt head;

[0033] Figure 3 yes Figure 2 Cross-sectional view;

[0034] Figure 4 This is a schematic diagram of the nut tightening tool provided in the embodiments of this application;

[0035] Figure 5 This is an assembly diagram of the bolt fastener tightening torque coefficient measuring device at -196℃ provided in the embodiments of this application;

[0036] in:

[0037] 1-Low-temperature environment chamber; 2-Bolt clamp; 3-Nut tightening tool; 4-Axial force gauge; 5-Test specimen bolt; 6-Test specimen nut;

[0038] 21-Support platform; 22-Fixing platform; 23-Clamping plate; 24-Clamping plate bolt;

[0039] 31-Sleeve rod; 32-Water circulation disc.

[0040] To better illustrate this embodiment, some content in the accompanying drawings may be omitted, enlarged, or reduced. They are for illustrative purposes only and should not be construed as limiting the scope of this application. Detailed Implementation

[0041] To make the technical solution and advantages of this application clearer, the technical solution of this application will be described in a clearer and more complete manner below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of this application, and are only used to explain this application, not to limit this application. It should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, and other related parts can be referred to the general design.

[0042] Furthermore, unless otherwise defined, the technical or scientific terms used in this application description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The word "comprising" as used in this application description indicates that the concept preceding the word encompasses the concepts listed following the word and their equivalents, without excluding other related concepts.

[0043] Furthermore, the terms indicating location used in the description of this application are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation" and "connection" used in the description of this application should be interpreted broadly. For example, a connection can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand its specific meaning in this application according to the specific circumstances.

[0044] A device for measuring the torque coefficient of bolts and fasteners at -196℃, such as Figure 1 As shown, it includes a low-temperature environment chamber 1, a bolt clamp 2, a nut tightening tool 3, and an axial force gauge 4.

[0045] The low-temperature environment chamber 1 is used to maintain a low-temperature environment. It is a double-layered hollow structure chamber made of stainless steel or transparent material. The chamber is evacuated through a vacuum hole on the side wall between the two layers. After evacuation, the vacuum hole is sealed.

[0046] The upper part of the low-temperature environment chamber 1 is a detachable cover with a liquid nitrogen injection hole. During the test, liquid nitrogen is injected into the low-temperature environment chamber 1 through the liquid nitrogen injection hole to generate the required low-temperature environment, and then the liquid nitrogen injection hole is sealed.

[0047] Bolt clamp 2 is installed inside the low-temperature environment chamber 1 to clamp the head of bolt 5 on the test piece, such as... Figure 2-3 As shown, it includes a support platform 21, a fixing platform 22, a clamping plate 23, and clamping plate bolts 24.

[0048] The support platform 21 is placed at the bottom of the low-temperature environment chamber 1.

[0049] The fixed platform 22 is connected to the surface of the support platform 21. Specifically, the fixed platform 22 can be designed with a hexagonal connection at the bottom, which is bolted to the surface of the support platform 21. The top of the fixed platform 22 has a hexagonal groove, and the head of the test piece bolt 5 is inverted in the hexagonal groove.

[0050] There are six clamping plates 23, which are set in hexagonal grooves and are parallel to the six side walls of the hexagonal grooves.

[0051] There are six clamping bolts 24, which are threaded onto the six side walls of the hexagonal groove. The six clamping plates 23 are pressed against the six edges of the test piece bolt 5 head, so as to adaptably clamp the head of the test piece bolt 5 of different sizes.

[0052] One end of the nut tightening tool 3 is located outside the low-temperature environment chamber 1, used to connect the tightening drive tool and its torque sensor. The other end extends into the low-temperature environment chamber 1 to hold the test piece nut 6, tightening the test piece nut 6 onto the threaded rod of the test piece bolt 5, as shown. Figure 4 As shown, it includes a sleeve rod 31 and a water circulation disc 32.

[0053] One end of the sleeve 31 has a hexagonal boss located on the outside of the low-temperature environment chamber 1, which is used to connect the wrench drive tool and its torque sensor. The other end has a hexagonal sleeve that extends into the low-temperature environment chamber 1 through the through hole on the detachable cover, and is used to hold the test piece nut 6 and tighten the test piece nut 6 onto the thread of the test piece bolt 5.

[0054] The water circulation disc 32 is fitted around the outer periphery of the sleeve rod 31, located outside the low-temperature environment chamber 1, and is locked on both sides by locking nuts screwed onto the upper part of the sleeve rod 31. The water circulation disc 32 has an annular cavity, and is connected to a water source through a water circulation inlet and outlet on the side wall, allowing circulating water to flow in. This isolates the low temperature inside the low-temperature environment chamber 1 from the outside, keeping the end of the sleeve rod 31 located outside the low-temperature environment chamber 1 at room temperature and preventing low-temperature injury to the operator.

[0055] Different sizes of test piece nuts 6 can be adapted by replacing different sleeve rods 31.

[0056] The wrench drive tool can be a computer-controlled servo motor driver + servo motor + reducer drive mechanism, or it can be a manual torque wrench with electronic signal output. The torque sensor is used to measure the tightening torque between the test piece bolt 5 and the test piece nut 6. It is located outside the low temperature environment chamber 1 and does not need to work in a low temperature environment.

[0057] The axial force gauge 4 is fitted onto the outer circumference of the bolt 5 of the test piece. A washer is placed between the axial force gauge 4 and the head of the bolt 5, and a washer and sleeve are placed between the axial force gauge 4 and the nut 6 of the test piece. It is used to measure the preload force between the bolt 5 and the nut 6 of the test piece. The axial force gauge 4 is located inside the low-temperature environment chamber 1 and operates in a low-temperature environment. It needs to be calibrated at low temperature before the test.

[0058] Assembly drawing of the bolt fastener tightening torque coefficient measuring device at -196℃, as shown. Figure 5 As shown, the torque sensor and axial force gauge 4 can be connected to a high-speed data acquisition system to collect and record data. At the same time, multiple sets of thermocouples or platinum resistance temperature sensors can be attached or clamped in the test specimen bolts 5, test specimen nuts 6 and low temperature environment chamber 1, and connected to the high-speed data acquisition system to collect and record data for monitoring the temperature inside the low temperature environment chamber 1. The test will begin after the temperature meets the test requirements.

[0059] Based on the -196℃ bolt fastener torque coefficient measuring device disclosed in the above embodiments, the specific method for measuring the -196℃ bolt fastener torque coefficient is as follows:

[0060] Liquid nitrogen was introduced into the cryogenic environment chamber 1. After the temperature inside the chamber stabilized at -196°C, the torque coefficient of the bolt fasteners was measured.

[0061] Tighten the test piece nut 6 onto the threaded rod of the test piece bolt 5. During the tightening process, collect the torque and preload between the test piece bolt 5 and the test piece nut 6, and calculate the torque coefficient.

[0062] The bolt fastener tightening torque coefficient measuring device disclosed in the above embodiments is simple in structure, easy to operate, reliable in application, and low in cost. It can easily achieve rapid and accurate measurement of the bolt fastener tightening torque coefficient in a low temperature environment of -196℃.

[0063] The technical solution of this application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A device for measuring the torque coefficient of bolt fasteners at -196℃, characterized in that, Includes a low-temperature environment chamber (1), bolt clamps (2), nut tightening tools (3), and an axial force gauge (4); A liquid nitrogen injection hole is provided on the low-temperature environment chamber (1); The bolt clamp (2) is set inside the low temperature environment chamber (1) and is used to clamp the head of the bolt (5) of the test piece; One end of the nut tightening tool (3) is located outside the low temperature environment chamber (1) and is used to connect the tightening drive tool and its torque sensor. The other end extends into the low temperature environment chamber (1) and is used to hold the test piece nut (6) and tighten the test piece nut (6) onto the screw of the test piece bolt (5). The nut tightening tool (3) includes a sleeve (31) and a water circulation disc (32); One end of the sleeve rod (31) has a hexagonal boss located outside the low temperature environment chamber (1) for connecting the wrench drive tool and its torque sensor. The torque sensor is used to measure the torque between the test piece bolt (5) and the test piece nut (6). The other end of the sleeve (31) has a hexagonal sleeve that extends into the low temperature environment chamber (1) through the through hole at the top of the chamber (1) to hold the test piece nut (6) and tighten the test piece nut (6) onto the thread of the test piece bolt (5); The water circulation disc (32) is sleeved on the outer periphery of the sleeve rod (31), and has an annular cavity inside. It is connected to the water source through the water circulation inlet and water circulation outlet opened on the side wall, and the circulating water is introduced. The axial force gauge (4) is used to be fitted onto the outer circumference of the bolt (5) of the test piece to measure the preload between the bolt (5) and the nut (6) of the test piece.

2. The device for measuring the torque coefficient of bolts and fasteners at -196℃ according to claim 1, characterized in that, The low temperature environment chamber (1) is a double-layer hollow structure chamber made of stainless steel or transparent material. The vacuum is drawn through the air extraction hole on the side wall between the two layers. After vacuuming, the air extraction hole is sealed. The upper part of the low temperature environment chamber (1) is a detachable cover. The liquid nitrogen injection hole is opened on the detachable cover. Liquid nitrogen is injected into the low temperature environment chamber (1) through the liquid nitrogen injection hole to generate the required low temperature environment. Then the liquid nitrogen injection hole is sealed.

3. The device for measuring the torque coefficient of bolts and fasteners at -196℃ according to claim 2, characterized in that, The bolt clamp (2) includes a support platform (21), a fixing platform (22), a clamping plate (23), and clamping plate bolts (24); The support platform (21) is placed at the bottom of the low-temperature environment chamber (1); The fixed platform (22) is connected to the platform of the support platform (21) and has a hexagonal groove on the top. The head of the test piece bolt (5) is inverted in the hexagonal groove. There are six clamps (23), which are set in hexagonal grooves and are parallel to the six side walls of the hexagonal grooves; There are six clamp bolts (24), which are threaded onto the six side walls of the hexagonal groove. The six clamps (23) are pressed against the six edges of the test piece bolt (5) head to clamp the head of the test piece bolt (5).

4. The device for measuring the torque coefficient of bolts and fasteners at -196℃ according to claim 3, characterized in that, The bottom of the fixed platform (22) has a hexagonal connection, which is bolted to the table surface of the support platform (21).

5. The device for measuring the torque coefficient of bolts and fasteners at -196℃ according to claim 4, characterized in that, The wrench drive tool is a computer-controlled servo motor driver + servo motor + reducer drive mechanism, or a manual torque wrench with electronic signal output.

6. The device for measuring the torque coefficient of bolts and fasteners at -196℃ according to claim 5, characterized in that, A washer is placed between the axial force gauge (4) and the head of the test piece bolt (5), and a washer and sleeve are placed between the axial force gauge (4) and the test piece nut (6).

7. The device for measuring the torque coefficient of bolts and fasteners at -196℃ according to claim 6, characterized in that, The torque sensor and axial force gauge (4) are connected to the high-speed data acquisition system to collect and record data; Multiple sets of thermocouples or platinum resistance temperature sensors are attached or clamped inside the test specimen bolts (5), test specimen nuts (6) and low temperature environment chamber (1), and connected to a high-speed data acquisition system to collect and record data.

8. A method for measuring the tightening torque coefficient of bolts at -196℃, implemented based on the measuring device for the tightening torque coefficient of bolts at -196℃ as described in claim 7, characterized in that, include: Liquid nitrogen was introduced into the low-temperature environment chamber (1). After the temperature inside the low-temperature environment chamber (1) stabilized at -196°C, the torque coefficient of the bolt fasteners was measured. Tighten the test piece nut (6) onto the thread of the test piece bolt (5). During the tightening process, collect the torque and preload between the test piece bolt (5) and the test piece nut (6) and calculate the torque coefficient.

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