A precision measuring device for superconducting strand bending strain

Abstract

The present invention discloses a superconducting strand bending strain precision measuring device, comprising a support frame, a driving mechanism installed on the upper part of the support frame, and the output end of the driving mechanism is connected to a weighing sensor and a pressure transmission module in sequence from top to bottom along the vertical direction; a bending strain module is installed on the lower part of the support frame, and when the output end of the driving module moves downward, it can apply pressure to the superconducting strand placed on the bending strain module through the pressure transmission module. In the superconducting strand bending strain precision measuring device provided by the present invention, the driving force generated by the driving mechanism applies downward pressure to the superconducting strand, and the pressure value is detected by the weighing sensor, which can accurately control the size of the pressure value and realize real-time monitoring; the bending strain module of the present invention has a novel structural design, and the overall bending strain transmission structure is simple, which reduces the transmission error caused by the complex mechanical mechanism, and greatly improves the application accuracy and measurement accuracy of the bending strain of the superconducting strand.

Description

Technical Field

[0001] The invention belongs to the field of superconducting strand performance testing, and in particular relates to a superconducting strand bending strain precision measuring device. Background Art

[0002] Fusion energy, as a highly efficient and clean energy, has always been one of the ideal energy sources for mankind. The fully superconducting Tokamak magnetic confinement nuclear fusion reactor is a reliable device that can realize fusion power generation. Superconducting magnets are one of the key components in the Tokamak device. The core component of the superconducting magnet is the superconducting cable, which is made of a certain number of copper wires and superconducting strands twisted in multiple stages with different twisting pitches. Therefore, studying superconducting strands is one of the important tasks in the development of superconducting cables.

[0003] Different practical superconducting materials have different processing and preparation techniques, and their application scenarios are also different. 3 Low-temperature superconducting materials such as Sn are widely used in fusion devices, and MgB 2 Due to its high critical temperature, it is also used in the power transmission cables of accelerators. The high-magnetic field application of high-temperature superconductors, mainly bismuth (Bi-2212) and yttrium (YBCO / ReBCO), is also highly valued in large scientific facilities, power equipment and other fields.

[0004] In the process of twisting superconducting strands into superconducting cables and superconducting cables operating in electromagnetic conditions, the superconducting strands will inevitably bend to a certain extent due to the effects of mechanical and electromagnetic stresses. Excessive bending will cause the current carrying capacity (critical current) of the superconducting strands to decline significantly, especially for Nb 3 Therefore, accurately applying and measuring the bending strain of superconducting strands to determine the critical bending strain point when performance degradation occurs not only helps to obtain a more accurate relationship between critical current and bending strain, but is also more conducive to the design, manufacture and practical application of superconducting magnets.

[0005] At present, various low-temperature laboratories in the world have developed superconducting wire bending strain measurement devices with different structures. However, these devices still have problems such as large processing errors and assembly matching tolerances of various components of the device, and low measurement accuracy during the bending strain measurement process. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a precise measurement device for the bending strain of a conductor wire. The device has a novel structural design and a simple overall bending strain transmission structure, which reduces the transmission error caused by the complex mechanical mechanism and greatly improves the application accuracy and measurement accuracy of the bending strain of the superconducting conductor wire.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A superconducting strand bending strain precision measuring device includes a support frame, preferably, the support frame includes an upper support plate and a lower support plate arranged relatively, and a support rod located between the upper support plate and the lower support plate for fixing and connecting the upper support plate and the lower support plate; a driving mechanism is installed at the bottom of the upper support plate, the output end of the driving mechanism is vertically downward, and the output end of the driving mechanism is connected to a weighing sensor and a pressure transmission module in sequence from top to bottom along the vertical direction; a bending strain module is installed at the top of the lower support plate, and the bending strain module is located directly below the pressure transmission module; further, the driving mechanism is a Z-axis automatic slide installed at the bottom of the upper support plate, when the output end of the Z-axis automatic slide moves downward, it can synchronously drive the pressure transmission module to move downward, and apply downward pressure to the superconducting strand through the pressure transmission module, so as to realize the detection of the bending strain of the superconducting strand through the bending strain module. The driving mechanism composed of the Z-axis automatic slide in the present invention can control the overall assembly and the downward driving movement accuracy to about 1μm, with high controllability and high measurement accuracy, which is currently unattainable by the same type of free assembly. In order to facilitate the assembly between the Z-axis automatic slide and the weighing sensor, the output end of the Z-axis automatic slide and the weighing sensor are connected through a connecting plate. The bending strain module includes a support block, a bending strain detection module and a limit block; wherein:

[0009] The top surface of the support block is fixed with a number of positioning teeth for supporting the superconducting strands; further, the outer side of the support block is covered with two centrally symmetrical support shells, the interior of the support shells has a cavity for accommodating the support block, and the side wall of the support shell is provided with a window, the window is to prevent the support shell from blocking the limiting groove of the side wall of the support block, so as to facilitate the assembly of the bending strain rod; the top of the support shell is a support platform, the side wall of the support platform has an L-shaped notch, and the L-shaped notches of the two support shells are spliced ​​to form a space for the positioning teeth to extend; the top of the support platform has an arc groove for placing the superconducting strands. The arc groove is used to fix the position of the superconducting strands. Before testing, the stability of the position of the superconducting strands can be ensured by welding the superconducting strands to the support platform.

[0010] The bending strain detection module includes a bending strain rod and a strain gauge. The material of the bending strain rod is preferably Ti-6Al-4V alloy. The Ti-6Al-4V alloy has a thermal contraction coefficient similar to that of the superconducting strand. By selecting the bending strain rod made of Ti-6Al-4V alloy, the measurement accuracy of the superconducting wire strain can be improved. In addition, the Ti-6Al-4V alloy has good yield strength and tensile strength and good self-stability. The bending strain rod is a semi-I-shaped structure, including a relatively symmetrical first horizontal part and a second horizontal part, and a vertical part for connecting the first horizontal part and the second horizontal part; the free ends of the first horizontal part and the second horizontal part extend outward in the vertical direction to form a first protrusion and a second protrusion respectively. When the superconducting strand is placed on the positioning tooth, the bottom surface of the superconducting strand just contacts with the first protrusion; in order to allow the superconducting strand to be stably placed on the top of the first protrusion, a positioning groove is provided at the position where the top of the first protrusion contacts with the superconducting strand, and the size of the positioning groove is adapted to the superconducting strand. The strain gauge is symmetrically fixed on the inner wall surface of the first horizontal part and the second horizontal part; at least one limiting groove for placing the bending strain rod is opened on the side of the support block. Preferably, the upper part of the limiting groove is a first limiting part adapted to the size of the first horizontal part, and the lower part of the limiting groove is a second limiting part adapted to the size of the second horizontal part. The first limiting part can play a good limiting role on the first horizontal part, and the second limiting part can play a good limiting role on the second horizontal part, so that when the bending strain rod is placed in the limiting groove, its position can remain relatively stable and will not shake, thereby ensuring the measurement accuracy. The upper part of the limiting groove passes through the top surface of the support block, and the first protrusion passes through the top of the limiting groove and extends to the top of the support block and is at the same height as the positioning tooth, so that when the superconducting strand is placed on the positioning tooth, it can contact the first protrusion at the same time, so that the stress state of the superconducting strand can be transmitted to the bending strain detection module through the first protrusion; the limiting block is installed on the side wall of the support block to fix the position of the bending strain rod.

[0011] The pressure transmission module includes a transmission rod and a pressure block fixed at the bottom of the transmission rod. The pressure block is in the shape of a prism with a small top and a large bottom. The bottom surface of the pressure block is installed with curved teeth, which are used to apply external force to the superconducting strands. The curved teeth and the positioning teeth are arranged in an interlaced manner and are located on the same straight line.

[0012] A further solution also includes a limit frame, which includes a lower connecting flange fixed to the bottom of the support block, an upper connecting flange located directly above the lower connecting flange, and a connecting rod for connecting the lower connecting flange and the upper connecting flange; a central limit hole for the transmission rod to pass through is opened in the middle of the upper connecting flange, and the inner diameter of the central limit hole is adapted to the outer diameter of the transmission rod; the support block is fixed to the top of the lower connecting flange through a fixed base plate, and the lower connecting flange is fixed to the top of the lower support plate. The limit frame can play a certain positioning and guiding role on the transmission rod through its central limit hole, so that the transmission rod keeps moving vertically downward.

[0013] The above-mentioned Z-axis automatic slide, weighing sensor, strain gauge, etc. are all commercially available products, and their specific working principles are not described here. Those skilled in the art can select products with corresponding functions for use in the present invention according to actual needs.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] In the precise measurement device for bending strain of superconducting strands provided by the present invention, the driving force generated by the driving mechanism applies downward pressure to the superconducting strands, and the pressure value is detected by a weighing sensor, which can accurately control the size of the pressure value and realize real-time monitoring; compared with the existing test device, the driving mechanism in the present invention is reduced in size, the mechanical assembly error is reduced, and the range of bending strain that can be applied is greatly improved. The present invention can accurately transmit the bending strain generated by the superconducting strands to the strain gauges through the design of the bending strain rod in the bending strain detection module. The structure is simple, the transmission error caused by the complex mechanical mechanism is reduced, and the application accuracy and measurement accuracy of the bending strain of the superconducting strands are greatly improved; the bending strain module and the driving mechanism in the present invention can be designed as a detachable connection structure, which is convenient for replacing modules with different bending pitches, and is also convenient for the subsequent assembly of current leads to measure the critical current of the sample. The support frame in the present invention has a simple structure and high overall rigidity, so that the overall device has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the overall structure of the device for precisely measuring the bending strain of a superconducting strand provided by the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the pressure transmission module and the bending strain module;

[0018] Figure 3 is a structural schematic diagram of a support block;

[0019] Figure 4 It is a schematic diagram of the structure of the supporting shell;

[0020] Figure 5 It is a structural schematic diagram of the bending strain detection module;

[0021] Figure 6 A schematic diagram of the local structure where the superconducting strands are placed on top of the support block;

[0022] Figure numerals: 1-support frame, 11-upper support plate, 12-lower support plate, 13-support rod, 2-driving mechanism, 3-weighing sensor, 4-pressure transmission module, 41-transmission rod, 42-pressure block, 43-bending tooth, 5-bending strain module, 51-support block, 52-bending strain detection module, 521-bending strain rod, 5211-first horizontal part, 5212-second horizontal part, 5213-vertical part, 5214-first protrusion , 5215-second protrusion, 5216-positioning groove, 522-strain gauge, 53-limiting block, 54-positioning tooth, 55-limiting groove, 551-first limiting portion, 552-second limiting portion, 6-connecting plate, 7-limiting frame, 71-lower connecting flange, 72-upper connecting flange, 73-connecting rod, 74-center limiting hole, 8-fixed base plate, 9-support shell, 91-window, 92-support platform, 93-arc groove, 10-superconducting strand. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0024] In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional means in the prior art in the art, and therefore, they are not described in detail; the parts in the following embodiments are all parts by weight.

[0025] It should be noted that in the present invention, "installation", "connection", "fixed connection" and the like all mean that two interconnected parts are fixed together, generally by welding, screws or gluing. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation of the present invention. The terms "first" and "second" do not represent specific quantities and orders, but are only used to distinguish names.

[0027] refer to Figures 1 to 6A superconducting strand bending strain precision measuring device comprises a support frame 1 for supporting the entire measuring device, preferably, the support frame 1 comprises an upper support plate 11 and a lower support plate 12 arranged relatively to each other, and a support rod 13 located between the upper support plate 11 and the lower support plate 12 for fixing and connecting the upper support plate 11 and the lower support plate 12; a driving mechanism 2 is installed at the bottom of the upper support plate 11, the output end of the driving mechanism 2 is vertically downward, and the output end of the driving mechanism 2 is sequentially connected with a weighing sensor 3 and a pressure transmission module 4 in the vertical direction from top to bottom; a bending strain module 5 is installed at the top of the lower support plate 12, and the bending strain module 5 is located 2-3mm directly below the pressure transmission module 4; further, the driving mechanism 2 is a Z-axis automatic slide installed at the bottom of the upper support plate 11, when the output end of the Z-axis automatic slide moves downward, it can synchronously drive the pressure transmission module 4 to move downward, and exert downward pressure on the superconducting strand 10 through the pressure transmission module 4, so as to realize the detection of the bending strain of the superconducting strand 10 through the bending strain module 5. In order to facilitate the assembly between the Z-axis automatic slide and the weighing sensor 3, the output end of the Z-axis automatic slide is connected to the weighing sensor 3 through a connecting plate 6. The bending strain module 5 includes a support block 51, a bending strain detection module 52 and a limit block 53; wherein:

[0028] refer to Figure 3 The top surface of the support block 51 is fixed with a plurality of positioning teeth 54 for supporting the superconducting strand 10; further, the outer side of the support block 51 is covered with two centrally symmetrical support shells 9, referring to Figure 4 The support shell 9 has a cavity for accommodating the support block 51, and a window 91 is provided on the side wall of the support shell 9; the top of the support shell 9 is a support platform 92, and the side wall of the support platform 92 has an L-shaped notch, and the L-shaped notches of the two support shells 9 are spliced ​​to form a space for the positioning teeth 54 to extend; the top of the support platform 92 has an arc groove 93 for placing the superconducting strand 10. The arc groove 93 is used to fix the position of the superconducting strand 10. Before the test, the superconducting strand 10 is welded to the support platform 92 to ensure the stability of the position of the superconducting strand 10.

[0029] refer to Figure 5The bending strain detection module 52 includes a bending strain rod 521 and a strain gauge 522. The material of the bending strain rod 521 is preferably Ti-6Al-4V alloy. The bending strain rod 521 is a semi-I-shaped structure, including a relatively symmetrical first horizontal portion 5211 and a second horizontal portion 5212, and a vertical portion 5213 for connecting the first horizontal portion 5211 and the second horizontal portion 5212; the free ends of the first horizontal portion 5211 and the second horizontal portion 5212 extend outward along the vertical direction to form a first protrusion 5214 and a second protrusion 5215, respectively. When the superconducting strand 10 is placed on the positioning tooth 54, the bottom surface of the superconducting strand 10 just contacts the first protrusion 5214; in order to allow the superconducting strand 10 to be stably placed on the top of the first protrusion 5214, a positioning groove 5216 is provided at the position where the top of the first protrusion 5214 contacts the superconducting strand 10, and the size of the positioning groove 5216 is adapted to the superconducting strand 10. The strain gauge 522 is symmetrically fixed on the inner wall surface of the first horizontal portion 5211 and the second horizontal portion 5212; at least one limiting groove 55 for placing the bending strain rod 521 is provided on the side of the support block 51. Preferably, the upper portion of the limiting groove 55 is a first limiting portion 551 adapted to the size of the first horizontal portion 5211, and the lower portion of the limiting groove 55 is a second limiting portion 552 adapted to the size of the second horizontal portion 5212. As an embodiment, the number of limiting grooves 55 is four, that is, two are provided on each of the two sides of the support block 51, and the four limiting grooves 55 are arranged in a staggered manner. Figure 3 The upper part of the limiting groove 55 passes through the top surface of the support block 51, and the first protrusion 5214 passes through the top of the limiting groove 55 and extends to the top of the support block 51 and is located at the same height as the positioning tooth 54, so that when the superconducting strand 10 is placed on the positioning tooth 54, it can contact the first protrusion 5214 at the same time, so that the stress state of the superconducting strand 10 can be transmitted to the bending strain detection module 52 through the first protrusion 5214; the limiting block 53 is installed on the side wall of the support block 51 to fix the position of the bending strain rod 521.

[0030] refer to Figure 2 The pressure transmission module 4 includes a transmission rod 41 and a pressure block 42 fixed at the bottom of the transmission rod 41. The pressure block 42 is in the shape of a prism with a small top and a large bottom. The bottom surface of the pressure block 42 is installed with curved teeth 43, and the curved teeth 43 are used to apply external force to the superconducting strand 10. The curved teeth 43 and the positioning teeth 54 are arranged in a staggered manner and are located on the same straight line.

[0031] As a preferred embodiment, refer to Figure 1 and Figure 2The present superconducting strand bending strain precision measuring device also includes a limit frame 7, which includes a lower connecting flange 71 fixed to the bottom of the support block 51, an upper connecting flange 72 located directly above the lower connecting flange 71, and a connecting rod 73 for connecting the lower connecting flange 71 and the upper connecting flange 72; a central limit hole 74 for the transmission rod 41 to pass through is opened in the middle of the upper connecting flange 72, and the inner diameter of the central limit hole 74 is adapted to the outer diameter of the transmission rod 41; the support block 51 is fixed to the top of the lower connecting flange 71 through the fixed base plate 8, and the lower connecting flange 71 is fixed to the top of the lower support plate 12. The limit frame 7 can play a certain positioning and guiding role on the transmission rod 41 through its central limit hole 74, so that the transmission rod 41 keeps moving vertically downward.

[0032] The method for using the superconducting strand bending strain precision measurement device provided by the present invention is as follows:

[0033] Before measurement, the superconducting strand 10 is first placed on the top of the positioning tooth 54. At this time, the first protrusion contacts the superconducting strand through the positioning groove 5216, and then the two ends of the superconducting strand are welded to the support platform 92 to prevent its position from moving during the measurement process, completing the installation of the superconducting strand. During measurement, the driving mechanism 2 pushes the connecting plate 6 downward, thereby synchronously driving the weighing sensor 3 and the pressure transmission module 4 to move downward. The transmission rod 41 in the pressure transmission module moves downward along the central limit hole 74 of the upper connecting flange 72, synchronously driving the pressure block 42 to move downward and apply downward pressure to the superconducting strand. The pressure of the superconducting strand is read by the weighing sensor 3, and the bending strain is transmitted to the bending strain rod 521 and read through the strain gauge 522 on the bending strain rod.

[0034] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Claims

1. A superconducting strand bending strain precision measurement device, characterized in that: The invention comprises a support frame, wherein a driving mechanism is installed on the upper part of the support frame, the output end of the driving mechanism is vertically downward, and the output end of the driving mechanism is connected with a weighing sensor and a pressure transmission module in sequence from top to bottom along the vertical direction; a bending strain module is installed on the lower part of the support frame, and the bending strain module is located directly below the pressure transmission module; when the output end of the driving module moves downward, it can apply pressure to the superconducting strand placed on the bending strain module through the pressure transmission module; wherein: The bending strain module includes a support block, a bending strain detection module and a limit block; a plurality of positioning teeth for supporting the superconducting strand are fixed on the top surface of the support block; the bending strain detection module includes a bending strain rod and a strain gauge, the bending strain rod is a semi-I-shaped structure, including a relatively symmetrical first horizontal part and a second horizontal part, and a vertical part for connecting the first horizontal part and the second horizontal part; the free ends of the first horizontal part and the second horizontal part extend outward in the vertical direction to form a first protrusion and a second protrusion respectively; the strain gauge is symmetrically fixed on the inner side wall surface of the first horizontal part and the second horizontal part; at least one limit groove for placing the bending strain rod is opened on the side of the support block, the upper part of the limit groove passes through the top surface of the support block, and the first protrusion passes through the top of the limit groove and extends to the top of the support block and is at the same height as the positioning tooth; the limit block is installed on the side wall of the support block to fix the position of the bending strain rod; The upper portion of the limiting groove is a first limiting portion adapted to the size of the first horizontal portion, and the lower portion of the limiting groove is a second limiting portion adapted to the size of the second horizontal portion; A positioning groove is provided at a position where the top of the first protrusion contacts the superconducting strand, and the size of the positioning groove is adapted to the superconducting strand.

2. The device for precisely measuring bending strain of a superconducting strand according to claim 1, characterized in that: The pressure transmission module includes a transmission rod and a pressure block fixed at the bottom of the transmission rod. The pressure block is in the shape of a prism with a small top and a large bottom. The bottom surface of the pressure block is installed with curved teeth. The curved teeth and the positioning teeth are arranged in an interlaced manner and are located on the same straight line.

3. The device for precisely measuring bending strain of superconducting strands according to claim 2, characterized in that: It also includes a limit frame, which includes a lower connecting flange fixed to the bottom of the support block, an upper connecting flange located directly above the lower connecting flange, and a connecting rod for connecting the lower connecting flange and the upper connecting flange; a central limit hole for a transmission rod to pass through is opened in the middle of the upper connecting flange, and the inner diameter of the central limit hole is adapted to the outer diameter of the transmission rod; the support block is fixed to the top of the lower connecting flange by a fixed base plate.

4. The device for precisely measuring bending strain of a superconducting strand according to claim 1, characterized in that: The outer side of the support block is covered with two centrally symmetrical support shells, the interior of the support shells is provided with a cavity for accommodating the support block, and the side walls of the support shells are provided with windows; the top of the support shells is a support platform, and the side walls of the support platform have an L-shaped notch, and the L-shaped notches of the two support shells are spliced ​​to form a space for the positioning teeth to extend out; the top of the support platform has an arc-shaped groove for placing superconducting strands.

5. The device for precisely measuring bending strain of superconducting strands according to claim 1, characterized in that: The bending strain rod is made of Ti-6Al-4V alloy.

6. The device for precisely measuring bending strain of superconducting strands according to claim 1, characterized in that: The driving mechanism is a Z-axis automatic slide installed on the bottom surface of the top of the support frame.

7. The device for precisely measuring bending strain of superconducting strands according to claim 1, characterized in that: The output end of the Z-axis automatic slide table is connected to the weighing sensor via a connecting plate.

8. The device for precisely measuring bending strain of a superconducting strand according to any one of claims 1 to 4, characterized in that: The support frame includes an upper support plate and a lower support plate that are arranged opposite to each other, and a support rod located between the upper support plate and the lower support plate for fixedly connecting the upper support plate and the lower support plate; the lower connecting flange is fixed on the top of the lower support plate.

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