Device and method for measuring local axial rigidity of end tooth connection structure

Abstract

The invention discloses an end tooth connection structure shaft local axial rigidity measuring device, which comprises a first support, a convex tooth drum, a concave tooth drum, a switching assembly, a force sensor and an adjusting assembly, and is characterized in that one end of the convex tooth drum is connected with the first support, and the other end of the convex tooth drum is connected with an end tooth at one end of the concave tooth drum; the other end of the concave tooth drum is connected with one end of the switching assembly, and the other end of the switching assembly is connected with the adjusting assembly through the force sensor so as to load axial tension or axial pressure through the adjusting assembly; through the combination of the switching assembly, the force sensor and the adjusting assembly, loading of the axial force is achieved, complex electromechanical equipment is not needed, the structure is simple, the axial force is conveniently applied, adjustment of the axial tension and pressure of the end teeth is achieved, the tension load and the pressure load are considered, and the axial force direction is very convenient to adjust.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and more specifically to a device and method for measuring the local axial stiffness of an end-tooth connection structure. Background Technology

[0002] End-tooth connection structures offer advantages such as stable connection and self-centering, making them widely used in gas turbine rotor connections. Typical gas turbine rotor connection structures include bolt-stop connections, sleeve-tooth connections, and end-tooth connections. Compared to bolt-stop connections, end-tooth connections offer stronger torsional transmission, simpler assembly, and self-centering; compared to sleeve-tooth connections, end-tooth connections boast higher axial stiffness, stronger resistance to bending deformation, and better connection stability. Therefore, end-tooth connection structures are increasingly widely used in new gas turbines. Because gas turbine rotors are subjected to axial relaxation and clamping forces caused by various loads such as aerodynamics, thermal loads, impacts, and rubbing during operation, the axial stiffness of the end-tooth connection structure is crucial for the safe operation of the entire rotor under axial forces.

[0003] In the journal *Mechanical Strength*, Vol. 21, No. 4, 1999, Hu Bo'an et al. pointed out that axial preload has a significant impact on the compression state of the rotor connected to the end teeth of the central tie rod. In the journal *Journal of Harbin Institute of Technology*, Vol. 48, No. 1, 2016, Xi Wenkui et al. simulated and tested the influence of axial preload on various stiffnesses of the end-tooth coupling. The results showed that the end-tooth compressive stiffness changes significantly with the preload, while other stiffnesses change relatively little. It is evident that the axial stiffness of the end-tooth connection structure is highly sensitive to axial force. Therefore, when designing the end-tooth structure parameters of a gas turbine rotor, it is essential to accurately measure the axial stiffness of the end-tooth connection structure.

[0004] Existing stiffness measurement devices for end-tooth connection structures are incomplete, unable to consider axial loads other than bolt preload, and also unable to simultaneously measure the compressive and tensile stiffness of the end-tooth connection structure. Existing invention patent CN118424617A discloses a simulation test device for the bending stiffness of a circular arc end-tooth tie rod rotor considering the influence of multiple loads, but it cannot measure the axial stiffness of the end-tooth connection structure. Existing invention patent CN116481748A discloses a multi-axis loading test device for the end-tooth connection structure of a gas generator rotor, capable of measuring the rotor stiffness characteristics under the combined influence of multi-directional loads, but its axial force application method is complex, requiring the use of a lead screw-bevel gear to change the direction of the force, and it cannot measure the local stiffness and tensile stiffness of the end-tooth connection structure. In the journal *Mechanical Strength*, Vol. 21, No. 4, 1999, Hu Bo'an et al. designed a compressive stiffness measuring tester for end-tooth couplings, but it can only apply bolt preload and measure the compressive stiffness of the end teeth.

[0005] To address the shortcomings of complex axial force loading, inability to simultaneously measure compressive and tensile stiffness, and inability to obtain local axial stiffness of end teeth when measuring the axial stiffness of end tooth connection structures, this invention proposes a device and method for measuring the local axial stiffness of end tooth connection structures. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a device and method for measuring the local axial stiffness of an end-tooth connection structure, which solves the problem that existing end-tooth connection structure stiffness measuring devices cannot consider axial loads other than bolt preload.

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

[0008] On one hand, a device for measuring the local axial stiffness of an end-tooth connection structure is provided, which includes a first support, a convex-tooth drum, a concave-tooth drum, a transition assembly, a force sensor, and an adjustment assembly. One end of the convex-tooth drum is connected to the first support, and the other end of the convex-tooth drum is connected to one end of the concave-tooth drum. The other end of the concave-tooth drum is connected to one end of the transition assembly, and the other end of the transition assembly is connected to the adjustment assembly through the force sensor, so that axial tensile force or axial compressive force can be applied through the adjustment assembly.

[0009] This invention achieves axial force loading through a combination of adapter components, force sensors, and adjustment components. It does not require complex electromechanical equipment, has a simple structure, and is convenient for applying axial force. It enables the adjustment of axial tension and pressure on the end teeth, taking into account both tensile and compressive loads, and the direction of axial force adjustment is very convenient.

[0010] Furthermore, the first support includes a first base plate, on which a first vertical plate is provided, and a central hole is opened in the middle of the first vertical plate, with one end of the toothed drum installed in the central hole.

[0011] Furthermore, the toothed drum includes a first drum, and a first inner flange and a first outer flange are respectively provided at both ends of the first drum;

[0012] The first outer flange is embedded in the center hole and is connected to the center flange inside the center hole.

[0013] The end face of the first inner flange is provided with end teeth protrusions on both sides of the flange through hole.

[0014] Furthermore, the concave toothed drum includes a second drum, and a second inner flange and a second outer flange are respectively provided at both ends of the second drum;

[0015] The end face of the second inner flange has end teeth that match the end teeth on both sides of the flange through hole. The first inner flange and the second inner flange are opposite each other and are connected by the end teeth through the matching of the end teeth, the end teeth and the flange through hole.

[0016] Furthermore, the adapter assembly includes an adapter drum and adapter bolts; the adapter drum includes a tapered third drum, one end of which is provided with a third outer flange, which is opposite to and movably connected to the second outer flange;

[0017] The other end of the third drum is equipped with a threaded cylinder, and one end of the adapter bolt is placed inside the threaded cylinder; the other end of the adapter bolt is connected to the force sensor.

[0018] Furthermore, the adjustment assembly includes a second support and a force-applying bolt; the second support includes a second base plate, a second vertical plate is provided on the second base plate, the force-applying bolt is provided through the upper part of the second vertical plate, and a first adjusting nut and a second adjusting nut sleeved on the force-applying bolt are respectively provided on both sides of the second vertical plate.

[0019] One end of the force-applying bolt is connected to the force sensor.

[0020] Furthermore, four mounting planes are evenly provided on the side of the first drum, and a first measuring ear is provided on each mounting plane.

[0021] Furthermore, four mounting planes are evenly provided on the side of the second drum, and a second measuring ear is provided on each mounting plane.

[0022] On the other hand, a measurement method based on a local axial stiffness measuring device for an end-tooth connection structure is provided, which includes the following steps:

[0023] Step S1: Assemble the measuring device and tighten the bolts between the first inner flange on the convex tooth drum and the second inner flange on the concave tooth drum to the expected torque.

[0024] Step S2: Adjust the first adjusting nut and the second adjusting nut to bring the output signal of the force sensor to zero, i.e., the axial force F ≈ 0; at the same time, measure the initial displacements x11, x12, x13 and x14 of the four first measuring ears, and the initial displacements x21, x22, x23 and x24 of the four second measuring ears respectively.

[0025] Step S3: Start measurement by rotating the first and second adjusting nuts to apply axial tension or axial pressure.

[0026] After step S4, when the axial tensile force or axial compressive force is applied, the displacements X11, X12, X13, and X14 of the four first measuring ears and the displacements X21, X22, X23, and X24 of the four second measuring ears are measured again.

[0027] Step S5: Calculate the average axial displacement of the first measuring ear under the action of axial force F. The average axial displacement of the second measuring ear The calculation method is as follows:

[0028]

[0029]

[0030] in, This indicates the displacement of the four first measuring ears after applying an axial force F. This indicates the displacement of the first four measuring ears before the application of the axial force F; This indicates the displacement of the four second measuring ears after applying an axial force F. This indicates the displacement of the first four second measuring ears before the application of the axial force F;

[0031] Step S6: Calculate the axial tensile stiffness k of the end tooth connection structure. The calculation method is as follows:

[0032]

[0033] Where F is the axial force; It is the average axial displacement of the first measured ear; is the average axial displacement of the second measuring ear; k is the axial tensile stiffness of the end tooth connection structure.

[0034] This invention discloses a device and method for measuring the local axial stiffness of an end-tooth connection structure, the advantages of which are:

[0035] 1. This invention achieves axial force loading through a combination of adapter, force sensor and adjustment component. It does not require complex electromechanical equipment, has a simple structure, and is convenient to apply axial force. By simultaneously adjusting the rotation direction of the adjusting nut, the axial tension and pressure of the end teeth can be adjusted, taking into account both tension and pressure loads. Furthermore, adjusting the direction of axial force is very convenient.

[0036] 2. In addition to applying the preload of the end tooth connecting bolt itself, the present invention can also apply external axial force through the force-applying bolt, and the center line of the axial force transmission component remains consistent. At the same time, the adapter drum is used to uniformly load the external axial force onto the end tooth structure, so that the external axial load is uniformly applied.

[0037] 3. The present invention sets four measuring surfaces evenly distributed along the circumference at the convex and concave teeth respectively, realizing the measurement of the local axial stiffness of the end teeth; the average displacement on the circumferential surface is used to characterize the axial displacement of the end teeth, reducing the influence of local deformation of the end teeth; at the same time, when calculating the stiffness of the end tooth connection structure, the initial displacement caused by the bolt preload is eliminated, improving the measurement accuracy. Attached Figure Description

[0038] Figure 1This is a schematic diagram of the structure of a local axial stiffness measuring device for an end-tooth connection structure according to the present invention.

[0039] Figure 2 This is a front view schematic diagram of a local axial stiffness measuring device for an end-tooth connection structure according to the present invention.

[0040] Figure 3 This is a side view of a device for measuring the local axial stiffness of an end-tooth connection structure according to the present invention.

[0041] Figure 4 For the present invention Figure 3 A schematic diagram of the cross-sectional structure at point AA.

[0042] Figure 5 This is a schematic diagram of the structure of the first support of the present invention.

[0043] Figure 6 This is a schematic diagram of the toothed drum of the present invention.

[0044] Figure 7 This is a schematic diagram of the concave toothed drum of the present invention.

[0045] Figure 8 This is a schematic diagram of the adapter component of the present invention.

[0046] Among them, 1. First support; 11. First base plate; 12. First vertical plate; 13. Center hole; 14. Center flange;

[0047] 2. Teethed drum; 21. First drum; 22. First inner flange; 23. First outer flange; 24. End teeth; 25. First measuring ear;

[0048] 3. Concave toothed drum; 31. Second drum; 32. Second inner flange; 33. Second outer flange; 34. End toothed concave tooth; 35. Second measuring ear;

[0049] 4. Adapter drum; 41. Third drum; 42. Third outer flange; 5. Adapter bolt; 6. Second support; 61. Second base plate; 62. Second vertical plate; 7. Force bolt; 81. First adjusting nut; 82. Second adjusting nut; 9. Force sensor. Detailed Implementation

[0050] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0051] Example 1

[0052] refer to Figures 1-8 This embodiment provides a local axial stiffness measuring device for an end-tooth connection structure. Its purpose is to solve the problem that existing end-tooth connection structure stiffness measuring devices cannot consider other axial loads besides bolt preload. The specific structure of this embodiment will be described in detail below.

[0053] A device for measuring the local axial stiffness of an end-tooth connection structure includes a first support 1, a convex tooth drum 2, a concave tooth drum 3, a connecting assembly, a force sensor 9, and an adjustment assembly.

[0054] Specifically, one end of the toothed drum 2 is connected to the first support 1, and the other end of the toothed drum 2 is connected to the end teeth of one end of the concave toothed drum 3; the other end of the concave toothed drum 3 is connected to one end of the adapter assembly, and the other end of the adapter assembly is connected to the adjustment assembly through the force sensor 9, so that axial tension or axial pressure can be applied through the adjustment assembly.

[0055] In this embodiment, the first support 1, the toothed drum 2, the toothed drum 3, the adapter assembly, the force sensor 9, and the adjustment assembly form a measuring device after assembly, and the center lines of the connection between the first support 1 and the toothed drum 2, the toothed drum 2, the toothed drum 3, the adapter assembly, the force sensor 9, and the adjustment assembly are on the same horizontal line.

[0056] Thus, by combining the adapter, force sensor 9, and adjustment component, the axial force of the end tooth can be applied without the need for complex electromechanical equipment. The structure is simple, the axial force is easy to apply, and the axial tension and pressure of the end tooth can be adjusted. It takes into account both tension and pressure loads, and the direction of the axial force is very convenient to adjust.

[0057] Specifically, the first support 1 includes a first base plate 11, on which a first vertical plate 12 is provided, and a central hole 13 is provided in the middle of the first vertical plate 12, and one end of the toothed drum 2 is installed in the central hole 13.

[0058] In this embodiment, the first support 1 is fixed to the ground or platform by the first base plate 11, the first vertical plate 12 is fixed on the first base plate 11 and is provided with reinforcing ribs to improve the axial stiffness of the first support 1. A central hole 13 is provided on the first vertical plate 12, and a central flange 14 is provided in the central hole 13 for fixing the toothed drum 2 by bolts.

[0059] Specifically, the toothed drum 2 includes a first drum 21, with a first inner flange 22 and a first outer flange 23 respectively provided at both ends of the first drum 21; the first outer flange 23 is embedded in the central hole 13 and is connected to the central flange 14 in the central hole 13; the end teeth 24 are respectively provided on both sides of the flange through hole on the end face of the first inner flange 22.

[0060] In this embodiment, the first outer flange 23 of the toothed drum 2 is embedded in the central hole 13, and the outer ring of the first outer flange 23 is interference-fitted into the central hole 13. The central flange 14 and the first outer flange 23 are connected by bolts, thereby connecting the toothed drum 2 to the first support 1.

[0061] Optionally, corresponding positioning holes are provided on the center flange 14 and the first outer flange 23 respectively, for use as positioning pins when the toothed drum 2 is installed on the first support 1.

[0062] Optionally, the toothed drum 2 is a cylindrical structure with unequal diameters, consisting of a first outer flange 23, a first drum 21, and a first inner flange 22. The outer diameter of the first outer flange 23 is larger than the outer diameter of the first drum 21, and the inner diameter of the first inner flange 22 is smaller than the inner diameter of the first drum 21.

[0063] Specifically, the concave-tooth drum 3 includes a second drum 31, and a second inner flange 32 and a second outer flange 33 are respectively provided at both ends of the second drum 31; the end face of the second inner flange 32 is provided with end tooth concave teeth 34 that match the end tooth protrusion 24 along both sides of the flange through hole; the first inner flange 22 and the second inner flange 32 are opposite to each other and are connected by end teeth through the cooperation of end tooth protrusion 24, end tooth concave teeth 34 and flange through hole.

[0064] In this embodiment, the end face of the first inner flange 22 on the toothed drum 2 is provided with end teeth 24 on both sides of the flange through hole, and the end face of the second inner flange 32 on the toothed drum 3 is provided with end teeth 34 that match the end teeth 24 on both sides of the flange through hole. The end teeth 24 and the end teeth 34 are used in pairs. After the end teeth 24 and the end teeth 34 are mated, the first inner flange 22 and the second inner flange 32 are connected by bolts.

[0065] Specifically, the adapter assembly includes an adapter drum 4 and an adapter bolt 5; the adapter drum 4 includes a tapered third drum 41, one end of which is provided with a third outer flange 42, which is opposite to and movably connected to a second outer flange 33; the other end of the third drum 41 is provided with a threaded cylinder, one end of which is placed inside the threaded cylinder; the other end of the adapter bolt 5 is connected to a force sensor 9.

[0066] In this embodiment, the third outer flange 42 is connected to the second outer flange 33 by bolts, thereby connecting the adapter drum 4 and the toothed drum 3; one end of the adapter bolt 5 is connected to the threaded cylinder at the other end of the third drum 41, and the other end of the adapter bolt 5 is connected to the force sensor 9.

[0067] Alternatively, the force sensor 9 can adopt existing technology, with threaded through holes at both ends, and can be a tension-compression integrated force sensor, including but not limited to one of the following: spoke-type force sensor, S-type force sensor, etc.

[0068] Optionally, the adapter drum 4 is a tapered drum structure that gradually tapers from one end to the other, consisting of an installation edge, a second outer flange 33, a tapered section, and a threaded cylinder. The inner ring of the second outer flange 33 is fitted and fixed to the installation edge of the adapter drum 4, while the length of the tapered section is limited by the overall axial dimension of the measuring device.

[0069] Optionally, the adapter bolt 5 consists of a left threaded section, a middle tightening edge, and a right threaded section. Both the left and right threaded sections are machined with external threads to connect with the threaded cylinder on the third drum 41 and the force sensor 9. The length of the left threaded section is greater than the length of the threaded cylinder on the third drum 41. The middle tightening edge is a tightening auxiliary structure for the left threaded section of the adapter bolt 5. Its cross-section is an equal hexagon, and the minimum width of the cross-section is greater than the outer diameter of the threaded cylinder on the third drum 41. The left end face of the middle tightening edge of the adapter bolt 5 is pressed against the right end face of the threaded cylinder on the third drum 41, and the right end face of the middle tightening edge of the adapter bolt 5 is pressed against the left end face of the force sensor 9. The external thread size of the right threaded section matches the internal thread size of the center threaded hole at the left end of the force sensor 9, and the length of the external thread of the right threaded section is not greater than the length of the center threaded hole at the left end of the force sensor 9.

[0070] Specifically, the adjustment assembly includes a second support 6 and a force-applying bolt 7; the second support 6 includes a second base plate 61, on which a second vertical plate 62 is provided, the force-applying bolt 7 is provided through the upper part of the second vertical plate 62, and a first adjusting nut 81 and a second adjusting nut 82 sleeved on the force-applying bolt 7 are respectively provided on both sides of the second vertical plate 62, and one end of the force-applying bolt 7 is connected to the force sensor 9.

[0071] In this embodiment, the second support 6 is fixed to the ground or platform by the second base plate 61, the second vertical plate 62 is fixed on the second base plate 61 and is provided with reinforcing ribs to improve the axial stiffness of the second support 6. The second vertical plate 62 is provided with mounting holes for force bolts 7, and the force bolts 7 are installed in the mounting holes. Both ends are fixed by the first adjusting nut 81 and the second adjusting nut 82 respectively.

[0072] Optionally, the inner ring surfaces of the first adjusting nut 81 and the second adjusting nut 82 are machined with through internal threads, the size of which matches the external thread size of the force-applying bolt 7. The outer ring surfaces of the first adjusting nut 81 and the second adjusting nut 82 are hexagonal in shape. The first adjusting nut 81 and the second adjusting nut 82 are screwed into the force-applying bolt 7 on both sides of the second vertical plate 62, with the right end face of the first adjusting nut 81 pressed against the left end face of the second vertical plate 62, and the left end face of the second adjusting nut 82 pressed against the right end face of the second vertical plate 62.

[0073] Optionally, the force-applying bolt 7 consists of a left threaded section, a middle tightening edge, and a right threaded section, wherein the left threaded section of the force-applying bolt has an external thread machined on its outer ring surface.

[0074] The left threaded section of the force-applying bolt 7 is screwed into the internal thread of the center threaded hole at the right end of the force sensor 9. The length of the left threaded section is not greater than the length of the center threaded hole at the right end of the force sensor 9. The middle tightening edge of the force-applying bolt 7 is a tightening auxiliary structure for the left threaded section of the force-applying bolt 7. It is a protruding part of the force-applying bolt 7 with an equal hexagonal cross-section. The left end face of the middle tightening edge of the force-applying bolt 7 contacts the right end face of the force sensor 9. The right threaded section of the force-applying bolt 7 passes through the mounting hole of the second vertical plate 62, and the length of the right threaded section is greater than the sum of the lengths of the first adjusting nut 81, the second vertical plate 62, and the second adjusting nut 82.

[0075] Specifically, four mounting planes are evenly provided on the side of the first drum 21, and a first measuring ear 25 is provided on each mounting plane.

[0076] In this embodiment, four mounting planes are evenly distributed along the circumference and mounted on the side of the first drum 21. The normal direction of the mounting plane is perpendicular to the direction of the center line of the first drum 21. A radial threaded hole is machined at the center of the mounting plane for mounting the first measuring ear 25. Optionally, the four mounting planes are evenly distributed along the circumference and located at 0°, 90°, 180° and 270° respectively.

[0077] Specifically, the second drum 31 has four mounting planes evenly distributed on its side, and each mounting plane is provided with a second measuring ear 35.

[0078] In this embodiment, four mounting planes are evenly distributed circumferentially on the side of the second drum 31. The normal direction of the mounting plane is perpendicular to the direction of the center line of the second drum 31. A radial threaded hole is machined at the center of the mounting plane for mounting the second measuring ear 35. Optionally, the four mounting planes are evenly distributed circumferentially at 45°, 135°, 225° and 315° respectively.

[0079] The first measuring ear 25 and the second measuring ear 35 are L-shaped structures, with the long arm and the short arm of the L-shape perpendicular to each other. A through hole is machined in the center of the short arm, and the center hole of the short arm is aligned with the threaded hole of the mounting plane. The first measuring ear 25 or the second measuring ear 35 is mounted on the mounting plane using bolts.

[0080] After the first measuring ear 25 or the second measuring ear 35 is installed, the top end face of the L-shaped long arm is perpendicular to the center line of the first drum 21 or the second drum 31. The top end face of the L-shaped long arm serves as the measuring surface for the axial displacement of the convex tooth drum 2 or the concave tooth drum 3, and is used to measure the axial displacement of the convex tooth drum 2 or the concave tooth drum 3.

[0081] Example 2

[0082] refer to Figures 1-8 This embodiment provides a measurement method based on a local axial stiffness measuring device for end-tooth connection structures. Its purpose is to solve the problem that existing end-tooth connection structure stiffness measuring devices cannot consider other axial loads besides bolt preload. The specific steps in this embodiment will be described in detail below.

[0083] A measurement method based on a local axial stiffness measuring device for an end-tooth connection structure includes the following steps:

[0084] Step S1: Assemble the measuring device and tighten the bolts between the first inner flange 22 on the toothed drum 2 and the second inner flange 32 on the toothed drum 3 to the expected tightening torque; in this embodiment, the bolt tightening torque is 75 N·m.

[0085] Step S2: Adjust the first adjusting nut 81 and the second adjusting nut 82 to bring the output signal of the force sensor 9 back to zero, i.e., the axial force F ≈ 0; at the same time, measure the initial displacements x11, x12, x13 and x14 of the four first measuring ears 25 and the initial displacements x21, x22, x23 and x24 of the four second measuring ears 35 respectively.

[0086] In this embodiment, the initial displacements of the four first measuring ears 25 are measured by sensors as x11=950μm, x12=1015μm, x13=1010μm, and x14=980μm, respectively, and the initial displacements of the four second measuring ears 35 are x21=965μm, x22=970μm, x23=960μm, and x24=980μm.

[0087] Step S3: Start measurement by rotating the first adjusting nut 81 and the second adjusting nut 82 to apply axial tension or axial pressure.

[0088] In this embodiment, when an axial tensile force is applied, the first adjusting nut 81 and the second adjusting nut 82 are rotated clockwise, causing the force-applying bolt 7 to tend to move to the right, thereby causing the force sensor 9 to generate an axial tensile force F.

[0089] When axial pressure is applied, the first adjusting nut 81 and the second adjusting nut 82 are rotated counterclockwise, causing the force bolt 7 to tend to move to the right and left, thereby generating an axial pressure F from the force sensor 9.

[0090] In this embodiment, to measure the axial tensile stiffness, an axial tensile force is applied, that is, the first adjusting nut 81 and the second adjusting nut 82 are rotated clockwise one turn, and the force sensor 9 outputs a tensile force signal F=10000N.

[0091] After step S4, when the axial tensile force or axial compressive force is applied, the displacements X11, X12, X13, and X14 of the four first measuring ears 25 and the displacements X21, X22, X23, and X24 of the four second measuring ears 35 are measured again.

[0092] In this embodiment, the sensors are used again to measure the displacements of the four first measuring ears 25 as X11=945μm, X12=1011μm, X13=1006μm, and X14=975μm, and the displacements of the four second measuring ears 35 as X21=956μm, X22=760μm, X23=950μm, and X24=971μm.

[0093] Step S5: Calculate the average axial displacement of the first measuring ear 25 under the action of axial force F. The average axial displacement of the second measuring ear 35 The calculation method is as follows:

[0094]

[0095]

[0096] in, i=1,2,3,4 represent the displacements of the four first measuring ears 25 after the axial force F is applied. i=1,2,3,4 represent the displacements of the first four measuring ears 25 before the application of the axial force F; i=1,2,3,4 represent the displacements of the four second measuring ears 35 after the axial force F is applied. i=1,2,3,4 represent the displacements of the first four second measuring ears 35 when the axial force F is applied;

[0097] In this embodiment, the average axial displacement of the first measuring ear 25 is calculated respectively. The average axial displacement of the second measuring ear 35 Specifically:

[0098]

[0099]

[0100] Step S6: Calculate the axial tensile stiffness k of the end tooth connection structure. The calculation method is as follows:

[0101]

[0102] Where F is the axial force; It is the average axial displacement of the first measuring ear 25; is the average axial displacement of the second measuring ear 35; k is the axial tensile stiffness of the end tooth connection structure.

[0103] In this embodiment, the axial tensile stiffness k of the end tooth connection structure is calculated as follows:

[0104]

[0105] In this embodiment, the process of measuring the axial compressive stiffness of the end-tooth connection structure is similar to that of measuring the axial tensile stiffness of the end-tooth connection structure. In step S3:

[0106] The process of measuring the axial compressive stiffness of the end-tooth connection structure is similar to that of measuring the axial tensile stiffness of the end-tooth connection structure. To measure the axial compressive stiffness of the end-tooth connection structure, axial pressure is applied in step S3, that is, the first adjusting nut 81 and the second adjusting nut 82 are rotated counterclockwise one turn, so that the force sensor 9 outputs a pressure signal F. The calculation method of axial compressive stiffness is the same as that of axial tensile stiffness.

[0107] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A device for measuring the local axial stiffness of an end-tooth connection structure, characterized in that: It includes a first support (1), a toothed drum (2), a toothed drum (3), a connecting assembly, a force sensor (9), and an adjustment assembly; One end of the toothed drum (2) is connected to the first support (1), and the other end of the toothed drum (2) is connected to the end teeth of one end of the concave drum (3); the other end of the concave drum (3) is connected to one end of the adapter assembly, and the other end of the adapter assembly is connected to the adjustment assembly through the force sensor (9) so that axial tension or axial pressure can be applied through the adjustment assembly.

2. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 1, characterized in that: The first support (1) includes a first base plate (11), on which a first vertical plate (12) is provided. A central hole (13) is provided in the middle of the first vertical plate (12), and one end of the toothed drum (2) is installed in the central hole (13).

3. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 2, characterized in that: The toothed drum (2) includes a first drum (21), and a first inner flange (22) and a first outer flange (23) are respectively provided at both ends of the first drum (21). The first outer flange (23) is embedded in the central hole (13) and is connected to the central flange (14) inside the central hole (13); The end face of the first inner flange (22) is provided with end teeth (24) on both sides of the flange through hole.

4. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 3, characterized in that: The concave toothed drum (3) includes a second drum (31), and the two ends of the second drum (31) are respectively provided with a second inner flange (32) and a second outer flange (33). The end face of the second inner flange (32) is provided with end tooth concave teeth (34) that match the end tooth protrusion (24) on both sides of the flange through hole. The first inner flange (22) and the second inner flange (32) are opposite to each other and are connected by end teeth through the cooperation of end tooth protrusion (24), end tooth concave teeth (34) and flange through hole.

5. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 4, characterized in that: The adapter assembly includes an adapter drum (4) and an adapter bolt (5); the adapter drum (4) includes a tapered third drum (41), one end of which is provided with a third outer flange (42), which is opposite to and movably connected to a second outer flange (33); The other end of the third drum (41) is provided with a threaded cylinder, and one end of the adapter bolt (5) is placed inside the threaded cylinder; the other end of the adapter bolt (5) is connected to the force sensor (9).

6. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 5, characterized in that: The adjustment assembly includes a second support (6) and a force-applying bolt (7); the second support (6) includes a second base plate (61), a second vertical plate (62) is provided on the second base plate (61), the force-applying bolt (7) is provided through the upper part of the second vertical plate (62), and a first adjusting nut (81) and a second adjusting nut (82) sleeved on the force-applying bolt (7) are respectively provided on both sides of the second vertical plate (62); One end of the force-applying bolt (7) is connected to the force sensor (9).

7. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 3, characterized in that: The first drum (21) has four mounting planes evenly distributed on its side, and each mounting plane is provided with a first measuring ear (25).

8. The device for measuring the local axial stiffness of the end-tooth connection structure according to claim 4, characterized in that: The second drum (31) has four mounting planes evenly distributed on its side, and each mounting plane is provided with a second measuring ear (35).

9. A measurement method for the local axial stiffness measuring device of the end-tooth connection structure according to claim 1, characterized in that, Includes the following steps: Step S1: Assemble the measuring device and tighten the bolts between the first inner flange (22) on the toothed drum (2) and the second inner flange (32) on the concave toothed drum (3) to the expected tightening torque; Step S2: Adjust the first adjusting nut (81) and the second adjusting nut (82) to make the output signal of the force sensor (9) return to zero, that is, the axial force F ≈ 0; at the same time, measure the initial displacements x11, x12, x13 and x14 of the four first measuring ears (25) and the initial displacements x21, x22, x23 and x24 of the four second measuring ears (35); Step S3: Start measurement by rotating the first adjusting nut (81) and the second adjusting nut (82) to apply axial tension or axial pressure. After step S4, when the axial tension or axial pressure is applied, the displacements X11, X12, X13, and X14 of the four first measuring ears (25) and the displacements X21, X22, X23, and X24 of the four second measuring ears (35) are measured again. Step S5: Calculate the average axial displacement of the first measuring ear (25) under the action of axial force F. The average axial displacement of the second measuring ear (35) The calculation method is as follows: ； ； in, (i=1,2,3,4) represent the displacements of the four first measuring ears (25) after the axial force F is applied. (i=1,2,3,4) represents the displacement of the first four first measuring ears (25) before the application of axial force F; (i=1,2,3,4) represent the displacements of the four second measuring ears (35) after the axial force F is applied. (i=1,2,3,4) represents the displacement of the first four second measuring ears (35) when the axial force F is applied; Step S6: Calculate the axial tensile stiffness k of the end tooth connection structure. The calculation method is as follows: ； Where F is the axial force; It is the average axial displacement of the first measuring ear (25); is the average axial displacement of the second measuring ear (35); k is the axial tensile stiffness of the end tooth connection structure.

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