A device and method for positioning and calibrating double strain gauges on the inner peripheral surface of a deep hole of a structural part

Abstract

The present invention discloses a device and method for positioning and calibrating double strain gauges on the inner circumference of a deep hole of a structural part, comprising a positioning cover and a positioning cylinder, wherein the outer circumference of the positioning cylinder corresponds to the inner circumference of the deep hole of the structural part; the side wall of the positioning cylinder has opening 1, opening 2, and opening 3, wherein opening 1 and opening 2 respectively have limiting edges for positioning strain gauges, and the positioning cylinder has convex teeth 1 and convex teeth 2 in opening 3 for calibrating the two strain gauges after positioning; the outer circumference of the positioning cylinder has through groove 1 connected to opening 1, through groove 2 connected to opening 2, and through groove 3 connected to opening 3, through groove 1, through groove 2, and through groove 3 all extending to the bottom of the positioning cylinder, and two strain gauges can simultaneously pass through the corresponding through grooves to take out the device, and two strain gauges can simultaneously pass through through groove 3 to take out the device. The present invention realizes the positioning and calibration of multiple strain gauges and improves the layout accuracy; it is particularly suitable for the case of arranging strain gauges in deeper holes, and can realize the measurement of the internal mechanical parameters of the structural part.

Description

Technical Field

[0001] The invention relates to the field of measurement technology, and in particular to a device and method for positioning and calibrating double strain gauges on the inner peripheral surface of a deep hole of a structural part. Background Art

[0002] There are many types of strain gauges, including metal foil, wire and film types. Among them, metal foil strain gauges are more commonly used in mechanical measurements of structures, and are also called foil strain gauges. The sensitive grid of the foil strain gauge is a very thin metal foil grid engraved using photolithography technology. According to different measurement requirements, sensitive grids of different shapes can be made, and different numbers of sensitive grids can be made on the same strain gauge. Foil strain gauges have the advantages of good heat dissipation conditions, large allowable current, small lateral effect, long fatigue life, simple production process, and suitable for mass production. They are widely used in transportation, automobile industry, shipbuilding, aerospace and other fields.

[0003] The adhesion level of strain gauges significantly affects the mechanical measurement results of structural parts. Generally, the adhesion area needs to be repeatedly polished to ensure that it is smooth enough and fixed with glue. Before the strain gauge is adhered, the oil stains on the adhesion area must be repeatedly cleaned, and lines must be drawn on the adhesion area to ensure that the orientation line of the strain gauge coincides with the line drawn on the adhesion area. When it is necessary to measure the stress in the hole of a structural part, especially when the hole is deep and the measuring part is far from the end face of the structural part, there are the following problems: first, it is difficult to draw lines at the adhesion area due to the small space; second, it is difficult to locate the positional relationship between the strain gauges when multiple strain gauges are adhered; third, it is difficult to calibrate the accurate orientation of each strain gauge after the strain gauge is adhered. This makes the adhesion of strain gauges more difficult. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a double strain gauge positioning and calibration device and method for the inner surface of a deep hole of a structural part, which has the characteristics of simple structure, easy implementation, low manufacturing cost, economy and practicality, and wide application range.

[0005] The present invention is implemented as follows: a double strain gauge positioning and calibration device for the inner circumference of a deep hole of a structural member, comprising a positioning cover and a positioning cylinder, wherein one end of the positioning cover and the positioning cylinder are fixedly connected; the positioning cover has a lower plane, which can be fitted with the end surface of the structural member, and the outer circumference of the positioning cylinder corresponds to the inner circumference of the deep hole of the structural member, so that the positioning cylinder and the structural member are in sliding contact; the strain gauge is a sheet structure, having a long side and a short side;

[0006] The side wall of the positioning cylinder has opening 1, opening 2, and opening 3. The opening 1 has limiting edge 1 and limiting edge 2 for positioning the first strain gauge. The limiting edge 1 and limiting edge 2 are perpendicular and intersect to form a positioning angle for positioning the first strain gauge. The opening 2 has limiting edge 3 and limiting edge 4 for positioning the second strain gauge. The limiting edge 3 and limiting edge 4 are perpendicular and intersect to form a positioning angle for positioning the second strain gauge. The limiting edge 2 and limiting edge 4 are parallel to the lower plane of the positioning cover, and the distances from the limiting edge 2 and limiting edge 4 to the lower plane of the positioning cover are equal.

[0007] The positioning cylinder has a convex tooth 1 and a convex tooth 2 in the opening 3 for calibrating the two strain gauges after positioning, the convex tooth 1 and the convex tooth 2 are of the same size, the arc length between the convex tooth 1 and the convex tooth 2 is equal to the arc length between the two positioning angles, the sum of the thickness of the convex tooth 1 or the convex tooth 2 and the thickness of the strain gauge is less than or equal to the thickness of the side wall of the positioning cylinder, the convex tooth 1 has a ratio side 2, the ratio side 2 corresponds to the short side of the first strain gauge, the convex tooth 2 has a ratio side 5, the ratio side 5 corresponds to the short side of the second strain gauge, the ratio side 2 and the ratio side 5 are both parallel to the lower plane of the positioning cover, and the distances between the ratio side 2 and the ratio side 5 and the lower plane of the positioning cover are equal;

[0008] The outer circumferential surface of the positioning tube has a through groove one connected to the opening one, and the through groove one extends to the bottom of the positioning tube. The outer circumferential surface of the positioning tube has a through groove two connected to the opening two, and the through groove two extends to the bottom of the positioning tube. Two strain gauges can simultaneously pass through the corresponding through grooves to take out the positioning and calibration device; the outer circumferential surface of the positioning tube has a through groove three connected to the opening three, and the through groove three extends to the bottom of the positioning tube. Two strain gauges can simultaneously pass through the through groove three to take out the positioning and calibration device.

[0009] Preferably, the central angle between the two positioning angles is 90°.

[0010] Preferably, the size of the convex tooth 1 and the convex tooth 2 is the same as the size of the strain gauge, the convex tooth 1 further has a ratio side 1 and a ratio side 3, the ratio side 1 and the ratio side 3 are both perpendicular to the ratio side 2, the ratio side 1 and the ratio side 3 respectively correspond to the two long sides of the first strain gauge, the convex tooth 2 further has a ratio side 4 and a ratio side 6, the ratio side 4 and the ratio side 6 are both perpendicular to the ratio side 5, the ratio side 4 and the ratio side 6 respectively correspond to the two long sides of the second strain gauge.

[0011] Preferably, the positioning cover is a hollow plate-like structure and also has an upper plane; the upper plane has positioning groove one, positioning groove two, positioning groove three, and positioning groove four, the positioning groove one points along the groove to the center of the upper plane of the positioning cover, the positioning groove two points along the groove to the center of the upper plane of the positioning cover, the positioning groove three points along the groove to the center of the upper plane of the positioning cover, and the positioning groove four points along the groove to the center of the upper plane of the positioning cover; the positioning groove one points to the limiting edge one along the axial direction of the positioning cylinder, the positioning groove two points to the limiting edge three along the axial direction of the positioning cylinder, the positioning groove three points to the ratio edge one of the convex tooth one along the axial direction of the positioning cylinder, and the positioning groove four points to the ratio edge four of the convex tooth two along the axial direction of the positioning cylinder.

[0012] Preferably, the sizes of the opening 1 and the opening 2 are equal, and the sizes of the through slot 1 and the through slot 2 are equal.

[0013] Preferably, the positioning tube is a thin-walled cylindrical structure, the cross-section of the deep hole of the structural component is circular, and the outer diameter of the positioning tube is equal to the diameter of the deep hole of the structural component.

[0014] The above-mentioned method for positioning and calibrating double strain gauges on the inner peripheral surface of a deep hole of a structural component includes a double strain gauge positioning process and a double strain gauge calibration process;

[0015] The dual strain gauge positioning process uses the following steps:

[0016] Step 1: insert the positioning cylinder into the deep hole of the structural member, the outer circumference of the positioning cylinder is in sliding contact with the inner circumference of the deep hole, the lower plane of the positioning cover is in contact with the end face of the structural member, and the positioning and calibration device is fixed;

[0017] Step 2: Insert the first strain gauge and the second strain gauge through the positioning cover into the interior of the positioning cylinder, align the long side of the first strain gauge with the limiting side 1, and align the short side of the first strain gauge with the limiting side 2, and glue and fix the first strain gauge; align the long side of the second strain gauge with the limiting side 3, and align the short side of the second strain gauge with the limiting side 4, and glue and fix the second strain gauge;

[0018] Step 3: Rotate the positioning and calibration device so that the short sides of the first strain gauge all enter the first through slot and the short sides of the second strain gauge all enter the second through slot; then slowly remove the positioning and calibration device in the direction of escaping from the deep hole, and remove the wires of the first strain gauge and the second strain gauge from the positioning and calibration device;

[0019] The dual strain gauge calibration process uses the following steps:

[0020] Step 1: Pass the wires of the first strain gauge and the second strain gauge through the opening 3 into the interior of the positioning cylinder, and then pass through the interior of the positioning cover, align the third positioning groove with the long side of the first strain gauge, insert the positioning cylinder into the deep hole of the structural member, the outer circumference of the positioning cylinder is in sliding contact with the inner circumference of the deep hole, and the lower plane of the positioning cover is in contact with the end face of the structural member;

[0021] Step 2, rotating the positioning and calibration device until the short side of the first strain gauge completely coincides with the second shorter side of the convex tooth 1;

[0022] Step 3, observe whether the long sides on both sides of the first strain gauge coincide with the ratio side 2 and the ratio side 3 respectively; observe whether the short side of the second strain gauge completely coincides with the ratio side 5 of the convex tooth 2, and whether the long sides on both sides of the second strain gauge coincide with the ratio side 4 and the ratio side 6 respectively;

[0023] Step 4: slowly take out the positioning and calibration device along the direction of escaping from the deep hole, and take out the wires of the first strain gauge and the second strain gauge from the positioning and calibration device.

[0024] The present invention has the following advantages and beneficial effects:

[0025] 1. The positioning and calibration device of the present invention does not need to mark the strain gauge pasting position in the deep hole. It can not only position and arrange the strain gauge in the deep hole of the structural part, but also realize the calibration of the strain gauge pasting position, realize the positioning and calibration of multiple strain gauges, and significantly improve the positioning accuracy of the strain gauge.

[0026] 2. The positioning and calibration device of the present invention realizes the absolute spatial positioning of two strain gauges, which is particularly suitable for the case where strain gauges are arranged in deeper holes, and can realize the measurement of the internal mechanical parameters of the structural parts.

[0027] 3. The positioning and calibration device of the present invention has the characteristics of simple structure, easy implementation, convenient maintenance, low manufacturing cost, economical and practical, and wide application range. It reduces the strain gauge arrangement deviation caused by manual operation. Different operators can achieve the same strain gauge positioning arrangement, providing a unified standard for the positioning and arrangement of double strain gauges on the inner surface of deep holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the positioning and calibration device and the structural parts of the present invention before positioning;

[0029] Figure 2 It is a schematic diagram of the structure of the positioning and calibration device and the structural parts of the present invention after being cut open and shown after positioning;

[0030] Figure 3 is a schematic diagram of the structure of the strain gauge corresponding to the positioning and calibration device of the present invention;

[0031] Figure 4The structure diagram of the positioning and calibration device of the present invention is shown in FIG. Figure 1 ;

[0032] Figure 5 The structure diagram of the positioning and calibration device of the present invention is shown in FIG. Figure 2 ;

[0033] Figure 6 It is a structural schematic diagram of the positioning and calibration device of the present invention cooperating with the strain gauge during positioning;

[0034] Figure 7 It is a schematic diagram of the structure of the positioning and calibration device of the present invention cooperating with the strain gauge during calibration;

[0035] Figure 8 It is a structural schematic diagram of the spatial position of the strain gauge of the present invention within the structural component.

[0036] In the figure, 1, structural member; 2, deep hole; 3, inner circumference; 4, positioning and calibration device; 5, positioning cover; 6, positioning cylinder; 7, first strain gauge; 8, second strain gauge; 9, long side; 10, short side; 11, upper plane; 12, lower plane; 13, opening 1; 14, opening 2; 15, opening 3; 16, limiting side 1; 17, limiting side 2; 18, limiting side 3; 19, limiting side 4; 20. Wire; 21. Positioning slot one; 22. Positioning slot two; 23. Positioning slot three; 24. Positioning slot four; 25. Through slot one; 26. Through slot two; 27. Through slot three; 28. Space one; 29. ​​Space two; 30. Space three; 31. Protruding tooth one; 32. Ratio side one; 33. Ratio side two; 34. Ratio side three; 35. Protruding tooth two; 36. Ratio side four; 37. Ratio side five; 38. Ratio side six. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like 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 orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. For example, the inner side refers to the side closer to the axis of the deep hole 2, and similarly, the outer side refers to the side away from the axis of the deep hole 2, and the upper side refers to the side away from the structural member 1, and similarly, the lower side refers to the side closer to the structural member 1. Unless otherwise specified, these relative terms should be understood in conjunction with the orientation of the components shown in the drawings.

[0039] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] Example

[0041] See also Figure 1 to Figure 5 , this embodiment provides a dual strain gauge positioning and calibration device for the inner circumference of a deep hole in a structural component, comprising a positioning cover 5 and a positioning cylinder 6, wherein the positioning cylinder 6 is a cylindrical structure. In a preferred embodiment, the positioning cylinder 6 is a thin-walled cylindrical structure. The structural component 1 has a deep hole 2, and the deep hole 2 has a certain depth. The cross-section of the deep hole 2 of the structural component 1 is circular, that is, the hole mouth is circular, and the bottom of the deep hole 2 is generally conical. This is because the structural component 1 generally adopts circular hole processing when opening the hole. The outer diameter of the positioning cylinder 6 is the same as the diameter of the deep hole 2, so the positioning cylinder 6 can be embedded in the deep hole 2 of the structural component 1, and the outer circumference of the positioning cylinder 6 is in close contact with the inner circumference 3 of the deep hole 2.

[0042] like Figure 3 As shown, the strain gauge is a sheet-like structure with a small thickness, a long side 9 and a short side 10; the strain gauge also has a front side and a back side, the front side has a metal wire, and the back side is a plane. Figure 2 , the first strain gauge 7 and the second strain gauge 8 have been positioned and installed, and the reverse sides of the first strain gauge 7 and the second strain gauge 8 are fixed to the inner peripheral surface 3 of the deep hole 2. The first strain gauge 7 and the second strain gauge 8 are often fixed by a transparent adhesive material, such as transparent glue. The first strain gauge 7 and the second strain gauge 8 also have a conductor 20, which is generally a double-core metal wire, used to transmit electrical energy and mechanical signals respectively.

[0043] like Figure 4 As shown, the positioning cover 5 is fixedly connected to one end of the positioning cylinder 6. When the first strain gauge 7 and the second strain gauge 8 are positioned, the positioning cover 5 is always outside the structural member 1. The positioning cover 5 is a hollow plate-like structure with an upper plane 11 and a lower plane 12. The lower plane 12 can fit with the end face of the structural member 1. As the positioning cylinder 6 is continuously embedded in the deep hole 2 of the structural member 1, the distance between the lower plane 12 and the opening of the deep hole 2 of the structural member 1 gradually decreases. When the lower plane 12 is close to the opening of the deep hole 2, the positioning and calibration device 4 has reached the predetermined position.

[0044] like Figure 4 and Figure 5 As shown, the positioning cylinder 6 has an opening 13, an opening 2 14, and an opening 3 15. The opening 13 has a limiting edge 16 and a limiting edge 2 17 for positioning the first strain gauge 7. The limiting edge 16 and the limiting edge 2 17 are perpendicular and intersecting to form a positioning angle for positioning the first strain gauge 7. The length of the limiting edge 16 is greater than the limiting edge 2 17. The limiting edge 16 and the limiting edge 2 17 are located at the corner of the opening 13. The limiting edge 2 17 corresponds to the short side 10 of the first strain gauge 7. The opening 2 14 has a limiting edge 3 18 and a limiting edge 4 19 for positioning the second strain gauge 8. The limiting edge 3 18 and the limiting edge 4 19 are perpendicular and intersecting to form a positioning angle for positioning the second strain gauge 8. The length of the limiting edge 3 18 is greater than the limiting edge 4 19. The third limiting side 18 and the fourth limiting side 19 are located at the corners of the second opening 14, and the fourth limiting side 19 corresponds to the short side 10 of the second strain gauge 8. The second limiting side 17 and the fourth limiting side 19 are parallel to the lower plane 12 of the positioning cover 5, and the distances from the second limiting side 17 and the fourth limiting side 19 to the lower plane 12 of the positioning cover 5 are equal.

[0045] When positioning the first strain gauge 7 and the second strain gauge 8, the first strain gauge 7 and the second strain gauge 8 need to be placed inside the positioning tube 6, and the long sides 9 of the first strain gauge 7 and the second strain gauge 8 are continuously placed inward along the depth direction of the deep hole 2, and at this time, the outer end of the wire 20 is facing away from the structural member 1.

[0046] like Figure 4As shown, the outer circumferential surface of the positioning cylinder 6 is provided with a through groove 25 connected with the opening 13, and the through groove 25 extends to the bottom of the positioning cylinder 6. The wall thickness at the through groove 25 is less than the wall thickness of the positioning cylinder 6. The through groove 25 is an arc-shaped structure. After the positioning cylinder 6 is placed in the deep hole 2, a space 28 is formed at the through groove 25 between the inner circumferential surface 3 of the structural member 1, through which the first strain gauge 7 passes. The limiting edge 17 is connected to the upper boundary of the through groove 25, and the upper boundary of the through groove 25 refers to the arc-shaped boundary facing the upper surface 11 of the positioning cover 5. The wall thickness at the limiting edge 17 is greater than the sum of the wall thickness at the through groove 25 and the thickness of the first strain gauge 7. Therefore, when the positioning and calibration device 4 rotates along the limiting edge 17 away from the upper boundary of the through groove 25, the front of the first strain gauge 7 is still at a certain distance from the outer surface at the through groove 25, so that when the positioning and calibration device 4 is taken out of the deep hole 2, the first strain gauge 7 will not be touched.

[0047] The outer circumferential surface of the positioning tube 6 is provided with a through groove 26 connected with the opening 2 14. The through groove 26 extends to the bottom of the positioning tube 6. The wall thickness at the through groove 26 is less than the wall thickness of the positioning tube 6. The through groove 26 is an arc-shaped structure. After the positioning tube 6 is placed in the deep hole 2, a space 29 is formed between the inner circumferential surface 3 of the structural member 1 at the through groove 26 through which the second strain gauge 8 passes. The limiting edge 3 19 is connected to the upper boundary of the through groove 26. The upper boundary of the through groove 26 refers to the arc-shaped boundary facing the upper surface 11 of the positioning cover 5. The wall thickness at the limiting edge 3 19 is greater than the sum of the wall thickness at the through groove 26 and the thickness of the second strain gauge 8. Therefore, when the positioning and calibration device 4 rotates along the limiting edge 3 19 away from the upper boundary of the through groove 26, the front of the second strain gauge 8 is still at a certain distance from the outer surface at the through groove 26, so that when the positioning and calibration device 4 is taken out of the deep hole 2, the second strain gauge 8 will not be touched.

[0048] In a preferred embodiment, the size of the opening 13 and the opening 2 14 are equal, and the two have the same geometric shape and size, that is, when the opening 2 14 is rotated along the axis of the positioning tube 6 by a certain angle, it can completely overlap and rotate to the position of the opening 13, and the opening 13 and the opening 2 14 maintain a fixed geometric angle; the size of the through slot 1 25 and the through slot 2 26 are equal, and the two have the same geometric shape; so that the first strain gauge 7 and the second strain gauge 8 are more convenient to simultaneously pass through the corresponding through slots to take out the positioning and calibration device 4. Of course, the size of the opening 13 and the opening 2 14 can also be different, and the opening 13 and the opening 2 14 of different shapes still need to ensure the geometric relationship between the positioning edge 16, the positioning edge 2 17, the positioning edge 3 18 and the positioning edge 4 19. The opening 13 and the opening 2 14 of different shapes can be used to identify the first strain gauge 7 and the second strain gauge 8 respectively.

[0049] like Figure 5As shown, the positioning cylinder 6 has a convex tooth 1 31 and a convex tooth 2 35 in the opening 3 15 for calibrating the two strain gauges after positioning, the convex tooth 1 31 and the convex tooth 2 35 are of the same size and the same size as the strain gauge, the arc length between the convex tooth 1 and the convex tooth 2 is equal to the arc length between the two positioning angles, and the sum of the thickness of the convex tooth 1 or the convex tooth 2 and the thickness of the strain gauge is less than or equal to the thickness of the side wall of the positioning cylinder. The convex tooth 1 31 has a ratio side 1 32, a ratio side 2 33 and a ratio side 34, the convex tooth 2 35 has a ratio side 4 36, a ratio side 5 37 and a ratio side 6 38, the ratio side 1 32 and the ratio side 34 are both perpendicular to the ratio side 2 33, the ratio side 4 36 and the ratio side 6 38 are both perpendicular to the ratio side 5 37, the ratio side 2 33 and the ratio side 5 37 are both parallel to the lower plane 12 of the positioning cover 5, and the distances between the ratio side 2 33 and the ratio side 5 37 and the lower plane 12 of the positioning cover 5 are equal.

[0050] The convex teeth 1 31 and the convex teeth 2 35 are both thin-walled structures. In a preferred embodiment, the convex teeth 1 31 and the convex teeth 2 35 have the same shape. The convex teeth 1 31 are used to calibrate the position of the first strain gauge 7, and the convex teeth 2 35 are used to calibrate the position of the second strain gauge 8. The convex teeth 1 31 and the convex teeth 2 35 jointly calibrate the geometric position relationship between the first strain gauge 7 and the second strain gauge 8.

[0051] The outer circumferential surface of the positioning tube 6 is provided with a through groove three 27 connected with the opening three 15, and the through groove three 27 extends to the bottom of the positioning tube 6. The wall thickness at the through groove three 27 is less than the wall thickness of the positioning tube 6. The through groove three 27 is an arc-shaped structure. After the positioning tube 6 is placed in the deep hole 2, a space three 30 is formed between the inner circumferential surface 3 of the structural member 1 at the through groove three 27 for the first strain gauge 7 and the second strain gauge 8 to pass through, so that the first strain gauge 7 and the second strain gauge 8 can simultaneously pass through the through groove three to take out the positioning and calibration device 4.

[0052] like Figure 4 As shown, the upper plane 11 of the positioning cover 2 has a positioning groove 1 21, a positioning groove 22, a positioning groove 3 23, and a positioning groove 4 24. The positioning groove 1 21 points along the groove to the center of the upper plane 11 of the positioning cover, the positioning groove 2 22 points along the groove to the center of the upper plane 11 of the positioning cover, the positioning groove 3 23 points along the groove to the center of the upper plane 11 of the positioning cover, and the positioning groove 4 24 points along the groove to the center of the upper plane 11 of the positioning cover.

[0053] The limiting edge 16 points to the positioning groove 1 21 along the axial direction of the positioning tube 6, and the limiting edge 3 18 points to the positioning groove 2 22 along the axial direction of the positioning tube 6. The positioning groove 1 21 indicates the position of the first strain 7, and the positioning groove 22 indicates the position of the second strain 8. The relative edge 1 32 points to the positioning groove 3 23 along the axial direction of the positioning tube 6, and the relative edge 4 36 points to the positioning groove 4 24 along the axial direction of the positioning tube 6. The positioning groove 3 23 indicates the position of the convex tooth 1 31, and the positioning groove 4 24 indicates the position of the convex tooth 2 35.

[0054] like Figure 6 As shown, when positioning the first strain gauge 7 and the second strain gauge 8, the following steps are adopted:

[0055] In the first step, the positioning cylinder 6 is inserted into the deep hole 2 of the structural member 1, the outer circumference of the positioning cylinder 6 is in sliding contact with the inner circumference 3 of the deep hole 2, the lower plane 12 of the positioning cover 5 is in contact with the end face of the structural member 1, and the positioning and calibration device 4 is fixed;

[0056] In the second step, the two wires 20 of the first strain gauge 7 and the two wires 20 of the second strain gauge 8 are respectively bound together, and the first strain gauge 7 and the second strain gauge 8 pass through the positioning cover 5 and enter the interior of the positioning cylinder 6. One end of each wire 20 is connected to the first strain gauge 7 and the second strain gauge 8, and the other end points to the outside of the structural member 1; according to the position of the first positioning groove 21, the long side 9 of the first strain gauge 7 is aligned with the limiting side 16, and the short side 10 of the first strain gauge 7 is aligned with the limiting side 2 17, and the first strain gauge 7 is fixed with a sticky substance such as glue;

[0057] The third step is to keep the positioning and calibration device 4 fixed, and align the long side 9 of the second strain gauge 8 with the third limiting side 18 according to the position of the second positioning groove 22, and align the short side 10 of the second strain gauge 8 with the fourth limiting side 19, and fix the second strain gauge 8 with a sticky material such as glue;

[0058] Step 4: Rotate the positioning and calibration device 4 along the limiting edge 19 away from the upper boundary of the through slot 2 26 (or along the limiting edge 17 away from the upper boundary of the through slot 1 25 ) until all the short sides 10 of the first strain gauge 7 enter the through slot 1 25 and all the short sides 10 of the second strain gauge 8 enter the through slot 2 26 ;

[0059] In the fifth step, the positioning and calibration device 4 is slowly taken out in the direction of the deep hole 2, and the wires 20 of the first strain gauge 7 and the second strain gauge 8 are taken out from the positioning tube 6 and the positioning cover 5 in turn.

[0060] like Figure 7 As shown, when calibrating the first strain gauge 7 and the second strain gauge 8, the following steps are adopted:

[0061] In the first step, the two wires 20 of the first strain gauge 7 and the two wires 20 of the second strain gauge 8 are passed through the opening 3 15 into the interior of the positioning cylinder 6, and then pass out from the interior of the positioning cover 5, and the third positioning groove 23 is aligned with the long side of the first strain gauge 7. The positioning cylinder 6 is inserted into the deep hole 2 of the structural member 1, and the outer surface of the positioning cylinder 6 is in sliding contact with the inner circumferential surface 3 of the deep hole 2, and the lower plane 12 of the positioning cover 5 is in contact with the end surface of the structural member 1;

[0062] The second step is to rotate the positioning and calibration device 4 until the short side 10 of the first strain gauge 7 completely coincides with the second side 33 of the convex tooth 1 31;

[0063] The third step is to observe whether the long sides 9 on both sides of the first strain gauge 7 coincide with the second ratio side 32 and the third ratio side 34 respectively. Since the second ratio side 32 and the third ratio side 34 are consistent with the geometric size of the first strain gauge 7, the first strain gauge 7 should not be observed on both sides of the convex tooth 1 31. Therefore, it is an ideal state when the first strain gauge 7 cannot be observed.

[0064] The fourth step is to observe whether the short side 10 of the second strain gauge 8 completely coincides with the ratio side 5 37 of the second convex tooth 35, and whether the long sides 9 on both sides of the second strain gauge 8 coincide with the ratio side 4 36 and the ratio side 6 38 respectively;

[0065] In the fifth step, the positioning and calibration device 4 is slowly taken out in the direction of the deep hole 2, and the wires 20 of the first strain gauge 7 and the second strain gauge 8 are taken out from the positioning tube 6 and the positioning cover 5 in turn.

[0066] It is worth noting that when positioning and calibrating the first strain gauge 7 and the second strain gauge 8 , although the wires 20 of the first strain gauge 7 and the second strain gauge 8 have a certain strength, special attention should be paid to ensure that the wires 20 are intact.

[0067] like Figure 8 As shown, the first strain gauge 7 and the second strain gauge 8 are parallel to the axis of the positioning cylinder 6 and also parallel to the axis of the deep hole 2 . Figure 8 In the embodiment, the central angle between the first strain gauge 7 and the second strain gauge 8 is 90°, which ensures that the first strain gauge 7 and the second strain gauge 8 measure stresses perpendicular to each other in the same plane. The actual force direction and force magnitude can be obtained by calculation, which is simple and effective.

[0068] The directions along the groove of the first positioning groove 21 are perpendicular to the directions along the groove of the second positioning groove 22 and the fourth positioning groove 24, respectively. The directions along the groove of the third positioning groove 23 are perpendicular to the directions along the groove of the second positioning groove 22 and the fourth positioning groove 24, respectively.

[0069] The positioning and calibration device 4 of the present invention does not need to mark the pasting position of the first strain gauge 7 and the second strain gauge 8. As long as the long side 9 of the first strain gauge 7 and the long side 9 of the second strain gauge 8 are respectively overlapped with the limiting side 16 and the limiting side 3 18, and the short side 10 of the first strain gauge 7 and the short side 10 of the second strain gauge 8 are respectively overlapped with the limiting side 2 17 and the limiting side 4 19, the first strain gauge 7 and the second strain gauge 8 can be accurately positioned and arranged in the deep hole 2 of the structural member 1, and the pasting position of the first strain gauge 7 and the second strain gauge 8 can be calibrated. The calibration method is simple and effective, and the positioning accuracy of the strain gauges is significantly improved.

[0070] When the hole depth of the deep hole 2 of the structural part 1 is relatively large, the ordinary strain gauge pasting method is difficult to apply due to space limitations. When there are multiple strain gauges, the absolute spatial positioning between the strain gauges is more difficult. The positioning and calibration device 4 of the present invention realizes the absolute spatial positioning of two strain gauges, which can be carried out according to the positioning method steps and the calibration method steps. It is particularly suitable for the case of arranging strain gauges in deeper holes, and can realize the measurement of the internal mechanical parameters of the structural part.

[0071] The positioning and calibration device 4 of the present invention is easy to maintain, and the positioning method and calibration method are simple and effective, which significantly reduces the strain gauge arrangement deviation caused by manual operation. Different operators can achieve the same strain gauge positioning and arrangement, providing a unified standard for the positioning and arrangement of double strain gauges on the inner circumference of a deep hole. When positioning and arranging strain gauges in multiple holes, the work efficiency can be significantly improved.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents, and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A double strain gauge positioning and calibration device for the inner surface of a deep hole of a structural part, characterized in that: It includes a positioning cover and a positioning cylinder, wherein one end of the positioning cover and the positioning cylinder are fixedly connected; the positioning cover has a lower plane, which can be fitted with the end surface of the structural member, and the outer circumference of the positioning cylinder corresponds to the inner circumference of the deep hole of the structural member, so that the positioning cylinder and the structural member are in sliding contact; the strain gauge is a sheet structure, having a long side and a short side; The side wall of the positioning cylinder has opening 1, opening 2, and opening 3. The opening 1 has limiting edge 1 and limiting edge 2 for positioning the first strain gauge. The limiting edge 1 and limiting edge 2 are perpendicular and intersect to form a positioning angle for positioning the first strain gauge. The opening 2 has limiting edge 3 and limiting edge 4 for positioning the second strain gauge. The limiting edge 3 and limiting edge 4 are perpendicular and intersect to form a positioning angle for positioning the second strain gauge. The limiting edge 2 and limiting edge 4 are parallel to the lower plane of the positioning cover, and the distances from the limiting edge 2 and limiting edge 4 to the lower plane of the positioning cover are equal. The positioning cylinder has a convex tooth 1 and a convex tooth 2 in the opening 3 for calibrating the two strain gauges after positioning, the convex tooth 1 and the convex tooth 2 are of the same size, the arc length between the convex tooth 1 and the convex tooth 2 is equal to the arc length between the two positioning angles, the sum of the thickness of the convex tooth 1 or the convex tooth 2 and the thickness of the strain gauge is less than or equal to the thickness of the side wall of the positioning cylinder, the convex tooth 1 has a ratio side 2, the ratio side 2 corresponds to the short side of the first strain gauge, the convex tooth 2 has a ratio side 5, the ratio side 5 corresponds to the short side of the second strain gauge, the ratio side 2 and the ratio side 5 are both parallel to the lower plane of the positioning cover, and the distances between the ratio side 2 and the ratio side 5 and the lower plane of the positioning cover are equal; The sizes of the convex tooth 1 and the convex tooth 2 are the same as the size of the strain gauge. The convex tooth 1 further has a ratio side 1 and a ratio side 3, the ratio side 1 and the ratio side 3 are both perpendicular to the ratio side 2, the ratio side 1 and the ratio side 3 correspond to the two long sides of the first strain gauge respectively, and the convex tooth 2 further has a ratio side 4 and a ratio side 6, the ratio side 4 and the ratio side 6 are both perpendicular to the ratio side 5, the ratio side 4 and the ratio side 6 correspond to the two long sides of the second strain gauge respectively; The outer circumferential surface of the positioning tube has a through groove one connected to the opening one, and the through groove one extends to the bottom of the positioning tube. The outer circumferential surface of the positioning tube has a through groove two connected to the opening two, and the through groove two extends to the bottom of the positioning tube. Two strain gauges can simultaneously pass through the corresponding through grooves to take out the positioning and calibration device; the outer circumferential surface of the positioning tube has a through groove three connected to the opening three, and the through groove three extends to the bottom of the positioning tube. Two strain gauges can simultaneously pass through the through groove three to take out the positioning and calibration device.

2. The double strain gauge positioning and calibration device for the inner peripheral surface of a deep hole of a structural component according to claim 1, characterized in that: The central angle between the two positioning angles is 90°.

3. The double strain gauge positioning and calibration device for the inner peripheral surface of a deep hole of a structural component according to claim 1, characterized in that: The positioning cover is a hollow plate-like structure and also has an upper plane; the upper plane has positioning groove one, positioning groove two, positioning groove three, and positioning groove four; the positioning groove one points along the groove to the center of the upper plane of the positioning cover, the positioning groove two points along the groove to the center of the upper plane of the positioning cover, the positioning groove three points along the groove to the center of the upper plane of the positioning cover, and the positioning groove four points along the groove to the center of the upper plane of the positioning cover; the positioning groove one points to the limiting edge one along the axial direction of the positioning cylinder, the positioning groove two points to the limiting edge three along the axial direction of the positioning cylinder, the positioning groove three points to the ratio edge one of the convex tooth one along the axial direction of the positioning cylinder, and the positioning groove four points to the ratio edge four of the convex tooth two along the axial direction of the positioning cylinder.

4. The double strain gauge positioning and calibration device for the inner peripheral surface of a deep hole of a structural component according to claim 1, characterized in that: The sizes of the opening 1 and the opening 2 are equal, and the sizes of the through slot 1 and the through slot 2 are equal.

5. The double strain gauge positioning and calibration device for the inner peripheral surface of a deep hole of a structural component according to claim 1, characterized in that: The positioning tube is a thin-walled cylindrical structure, the cross section of the deep hole of the structural component is circular, and the outer diameter of the positioning tube is equal to the diameter of the deep hole of the structural component.

6. A method for positioning and calibrating double strain gauges on the inner surface of a deep hole of a structural part using the device described in any one of claims 1 to 5, characterized in that: Including dual strain gauge positioning process and dual strain gauge calibration process; The dual strain gauge positioning process uses the following steps: Step 1: insert the positioning cylinder into the deep hole of the structural member, the outer circumference of the positioning cylinder is in sliding contact with the inner circumference of the deep hole, the lower plane of the positioning cover is in contact with the end face of the structural member, and the positioning and calibration device is fixed; Step 2: Insert the first strain gauge and the second strain gauge through the positioning cover into the interior of the positioning cylinder, align the long side of the first strain gauge with the limiting side 1, and align the short side of the first strain gauge with the limiting side 2, and glue and fix the first strain gauge; align the long side of the second strain gauge with the limiting side 3, and align the short side of the second strain gauge with the limiting side 4, and glue and fix the second strain gauge; Step 3: Rotate the positioning and calibration device so that the short sides of the first strain gauge all enter the first through slot and the short sides of the second strain gauge all enter the second through slot; then slowly remove the positioning and calibration device in the direction of escaping from the deep hole, and remove the wires of the first strain gauge and the second strain gauge from the positioning and calibration device; The dual strain gauge calibration process uses the following steps: Step 1: Pass the wires of the first strain gauge and the second strain gauge through the opening three into the interior of the positioning cylinder, and then pass through the interior of the positioning cover, align the positioning groove three with the long side of the first strain gauge, insert the positioning cylinder into the deep hole of the structural member, the outer circumference of the positioning cylinder is in sliding contact with the inner circumference of the deep hole, and the lower plane of the positioning cover is in contact with the end face of the structural member; Step 2, rotating the positioning and calibration device until the short side of the first strain gauge completely coincides with the second shorter side of the convex tooth 1; Step 3, observe whether the long sides on both sides of the first strain gauge coincide with the ratio side 2 and the ratio side 3 respectively; observe whether the short side of the second strain gauge completely coincides with the ratio side 5 of the convex tooth 2, and whether the long sides on both sides of the second strain gauge coincide with the ratio side 4 and the ratio side 6 respectively; Step 4: slowly take out the positioning and calibration device along the direction of escaping from the deep hole, and take out the wires of the first strain gauge and the second strain gauge from the positioning and calibration device.

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