A force detection device

Abstract

The present application relates to a kind of force detection devices, belong to electronic measuring instrument manufacturing technical field, solve the problem of big influence of force dimension coupling in existing contact force measurement technology.The present application includes installation base, friction block, friction block base and three force transmission structures.The central axes of three force transmission structures are orthogonal to each other, and the intersection point of adjacent central axes is respectively fixedly connected with friction block base, and the other end is respectively fixedly connected with the first support panel of installation base;Friction block is set on friction block base;Each force transmission structure includes a force transmission shaft, the transverse bending stiffness K b Of force transmission shaft is less than 1% of axial tension-compression stiffness K p The present application uses the force transmission shaft with transverse bending stiffness far less than axial tension-compression stiffness, reduces the influence of force dimension coupling, and improves measurement accuracy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electronic measuring instrument manufacturing, and particularly relates to a force detection device. BACKGROUND

[0002] In the technical field of electronic measuring instrument manufacturing, in the measurement of friction contact force, the contact force in each direction belongs to transverse force in other directions, so the measurement of the contact force in each direction is affected by the transverse component of the contact force in the remaining directions, thereby resulting in low measurement accuracy. The force coupling between different force directions makes it difficult to measure high-dimensional contact force and has large deviation.

[0003] In addition, the resonance of the force measurement structure has a significant impact on the measurement results. In the measurement of friction contact force, the contact surface is a pair of friction pairs, wherein the measured contact surface belongs to the moving part of the friction pair, and the static part of the friction pair is connected with the force detection device. Therefore, the force detection device needs to provide sufficient system stiffness for the static part of the friction pair.

[0004] The resonance of the force measurement structure will cause the structure deformation to increase, so that the measurement results of the force sensor are distorted. Contact force measurement often accompanies the determination of hysteresis loop, and the measurement of the hysteresis loop of the contact surface needs to accurately measure the contact force while ensuring the accuracy of the relative displacement measurement, and the resonance of the force measurement structure will affect the measurement of the relative displacement.

[0005] The current measurement scheme usually adopts commercial multi-dimensional force elements or mechanical decoupling force measurement structures. Commercial force elements often focus on the universality of the elements, and therefore are not suitable for special application scenarios. The existing mechanical decoupling force measurement structure scheme is often used for large-size structures such as aircraft landing gears, and does not pay attention to the structural stiffness, resulting in low structural stiffness and easy resonance.

[0006] For the measurement of the contact force of a small-size contact surface, the force measurement structure needs to have a small size to ensure accessibility for measuring the contact surface of a dry friction damping structure such as a blade crown or a convex shoulder. The force measurement structure also needs to have high system stiffness, which can increase the natural frequency to avoid measurement errors caused by resonance, and ensure that the structural response is much smaller than the measured object, thereby reducing the measurement error of the relative displacement between the contact surfaces.

[0007] Therefore, for the measurement of the contact force of the contact surface of the turbine blade with crown of the aero-engine, the force measurement structure needs to have a small size to ensure accessibility. The force measurement structure also needs to have high system stiffness, which can increase the natural frequency to avoid measurement errors caused by resonance, and ensure that the structural response is much smaller than the measured object, thereby reducing the measurement error of the relative displacement between the contact surfaces. SUMMARY

[0008] In view of the above analysis, the embodiments of the present application aim to provide a force detection device to solve the problems of low rigidity, easy resonance, poor accessibility and large force inter-axis coupling in the existing contact force measurement equipment.

[0009] In one aspect, the present application relates to a force detection device, comprising a mounting base, a friction block, a friction block base and three force transmission structures, the central axes of the three force transmission structures are perpendicular to each other, and one end of the intersection of the central axes of the three force transmission structures is fixedly connected with the friction block base, respectively, and the other end of the three force transmission structures is fixedly connected with the first support panel of the mounting base, respectively; the friction block is arranged on the friction block base; each of the force transmission structures comprises a force transmission shaft, the transverse bending stiffness K b of the force transmission shaft is less than 1% of the axial tensile and compressive stiffness K p .

[0010] Further, the friction block base comprises two second support panels and a third support panel which are perpendicular to each other; the friction block is arranged on an inner surface of the corner formed by the two second support panels and the third support panel; the three force transmission structures are vertically and fixedly connected with one of the two second support panels and the third support panel, respectively.

[0011] Further, the force transmission shaft is a hollow shaft structure, the force transmission shaft is divided into a first part, a second part and a third part along the axial direction; the first end of the first part is fixedly connected with the friction block base, the first end of the second part is fixedly connected with the second end of the first part, and the second end of the second part is fixedly connected with the first end of the third part.

[0012] Further, each of the force transmission structures further comprises a first force sensor adapter disc and a force sensor, the second end of the third part of the force transmission shaft is fixedly connected with the first force sensor adapter disc, one end of the first force sensor adapter disc is fixedly connected with the force sensor, and the other end of the force sensor is fixedly connected with the first force sensor adapter disc.

[0013] Further, the outer diameter of the first part is the same as that of the second part and smaller than that of the third part, and the inner diameter of the second part is the same as that of the third part and larger than that of the first part.

[0014] Further, the second part of the force transmission shaft is a plurality of circumferentially distributed ribs.

[0015] Further, the cross section of the rib can be any one of a fan ring shape, a trapezoidal shape, a rectangular shape or a circular shape.

[0016] Further, the gap between the ribs is in the range of 1-3 mm.

[0017] Further, the third part is provided with a plurality of positioning through holes, which extend axially and are uniformly distributed circumferentially.

[0018] Further, the mounting base comprises three first support panels orthogonal to each other; and each of the three first support panels is parallel to one of the two second support panels and one third support panel.

[0019] Further, the force sensor base is vertically and fixedly connected to the inner side surface of one of the two second support panels and one third support panel.

[0020] In another aspect, the present application also relates to a method for testing the mechanical characteristics of the shroud contact interface of a turbine blade of an aero-engine.

[0021] Further, the testing method comprises the following steps:

[0022] S1: mounting and fixing the blade root position of the turbine blade of the aero-engine on the clamp of the test bench;

[0023] S2: mounting the force detection device on the corresponding position of the test bench;

[0024] S3: making the friction block of the force detection device abut the contact surface of the shroud of the turbine blade of the aero-engine;

[0025] S4: applying excitation to the turbine blade of the aero-engine and recording the data fed back by the force sensor in the force detection device;

[0026] S5: calculating the data to obtain the mechanical characteristic parameters of the contact interface of the turbine blade of the aero-engine.

[0027] Further, in step S2, one or two force detection devices can be mounted.

[0028] Further, in step S3, the data fed back by the force sensor perpendicular to the surface of the friction block is between 0.1N and 0.2N.

[0029] Further, in step S4, the excitation applied to the turbine blade of the aero-engine is vibration excitation.

[0030] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0031] (1) The present application adopts the transverse bending stiffness K b which is smaller than the axial tensile and compressive stiffness K pThe power transmission shafts of 1% are used as flexible hinges in three mutually orthogonal power transmission structures, so that when the contact force transmits a directional force load to the power transmission structure, the power transmission structure in the direction bears most of the axial load, and the load borne by the transverse direction of the other two orthogonal power transmission structures can be ignored, thereby effectively reducing the force dimension coupling influence of the contact force measurement;

[0032] (2) The decoupling degree and structural stiffness are controlled by controlling the design parameters of the ribs of the power transmission shafts, so that the structure has sufficient structural stiffness to avoid resonance; in addition, the force measurement structure scheme of the present application adopts three orthogonal power transmission structures connected together through the friction block base to provide stiffness for the friction block base together, thereby improving the structural stiffness of the whole device; when friction contact occurs between the friction block and the contact surface of the turbine blade of the aero-engine, the friction block will not have a large vibration response or even resonance due to low structural stiffness, so as to ensure that the vibration displacement of the friction block is much smaller than the vibration displacement of the contact surface of the turbine blade of the aero-engine, thereby reducing the measurement error of the relative displacement of the contact surface;

[0033] (3) The present application extends the friction block base through three orthogonal power transmission structures, and installs the friction block as a friction pair static part on the friction block base to ensure accessibility, which can be used for contact force measurement of small size contact surfaces such as the blade crown contact surface of the aero-engine turbine blade crown, specifically, the friction block as a friction pair static part matched with the blade crown contact surface can be designed and installed on the friction block base according to the size and structure of the blade crown contact surface, since the position of the friction block is located at the end of the three orthogonal power transmission structure, therefore the structural size of the position of the friction block only depends on the friction block itself, and there is no interference between the friction block and the blade crown structure.

[0034] The present application reduces the force dimension coupling influence of the contact force measurement device and improves the structural stiffness from two aspects of power transmission shaft design and force measurement structure scheme design, thereby improving the contact force measurement precision and providing stiffness guarantee for the measurement of the hysteresis loop relative displacement.

[0035] In the present application, the above technical solutions can be combined with each other to realize more preferred combination schemes. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purposes and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0037] Figure 1 It is a structural schematic diagram of a force detection device of the present application;

[0038] Figure 2 This is a side view of a force detection device according to the present invention;

[0039] Figure 3 For along Figure 2 Sectional view of line AA in the middle;

[0040] Figure 4 This is a schematic diagram of the friction block base.

[0041] Figure 5 This is a schematic diagram of the friction block structure;

[0042] Figure 6 This is a structural diagram of the force transmission shaft in Embodiment 1 of the present invention;

[0043] Figure 7 This is a side view of the force transmission shaft according to Embodiment 1 of the present invention;

[0044] Figure 8 For along Figure 7 Sectional view of the middle BB line;

[0045] Figure 9 For along Figure 7 A cross-sectional view of the CC line;

[0046] Figure 10 This is a structural diagram of the force transmission shaft in Embodiment 2 of the present invention;

[0047] Figure 11 This is a side view of the force transmission shaft in Embodiment 2 of the present invention;

[0048] Figure 12 For along Figure 11 Sectional view of the DD line;

[0049] Figure 13 For along Figure 11 A cross-sectional view of the EE line;

[0050] Figure 14 A schematic diagram illustrating the measurement of the contact force on the crown contact surface of a crowned turbine blade using a force detection device according to the present invention;

[0051] Figure 15 for Figure 14 The front view;

[0052] Figure 16 For along Figure 15 A cross-sectional view of the FF line.

[0053] In the diagram: 1-Mounting base; 11-First support panel; 2-Friction block base; 21-Second support panel; 22-Third support panel; 3-Friction block; 4-Force transmission structure; 41, 41'-Force transmission shaft; 411, 411'-First part; 412, 412'-Second part; 4121, 4121'-Rib; 413, 413'-Third part; 4131, 4131'-Mounting through hole; 42-First force sensor adapter plate; 43-Force sensor; 44-Second force sensor adapter plate; 5-Double-ended screw; 6-Aircraft engine turbine blade. Detailed Implementation

[0054] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0055] Example 1

[0056] A specific embodiment of the present invention, such as Figure 1 , Figure 2 and Figure 3 As shown, a force detection device is disclosed, including a mounting base 1, a friction block base 2, a friction block 3, and three force transmission structures 4. The central axes of the three force transmission structures 4 are orthogonal to each other, and one end of the intersection of the adjacent central axes of the three force transmission structures 4 is fixedly connected to the friction block base 2, while the other end of each force transmission structure 4 is fixedly connected to the mounting base 1. The friction block 3 is mounted on the friction block base 2 as a stationary component of the friction pair. Each force transmission structure 4 includes a force transmission shaft 41, and the lateral bending stiffness K of the force transmission shaft 41 is... b Less than axial tensile / compressive stiffness K p 1%.

[0057] Among them, K b and K p The results can be obtained using the following formulas:

[0058]

[0059]

[0060]

[0061] γ represents the degree of decoupling;

[0062] L represents the length of the rib 4121 of the force transmission shaft 41, in mm;

[0063] A n This represents the cross-sectional area of ​​a single rib 4121, in mm. 2 ;

[0064] n represents the number of ribs;

[0065] E represents the elastic modulus of the material of the force transmission shaft 41.

[0066] According to the force detection device of the present application, when the friction block 3 is subjected to three-way contact force load, the force load is transmitted to the mounting base 1 through the force transmission structure 4, the three-way orthogonal force transmission structure 4 transmits different directions of force respectively, and the size of the transmitted axial force load is measured through the force sensor 43. Since the friction block base 2 connects the three-way orthogonal force transmission structure 4 together, in order to avoid the influence of force coupling between the force transmission structure 4 on the measurement results, the specific force transmission shaft 41 of the present application is used as the core part of the force transmission structure 4. The two ends of the force transmission shaft 41 are connected with the friction block base 2 and the force sensor 43 respectively, and the connection mode can be designed according to the size of the friction block base 2 and the force sensor 43. The second part 412 of the force transmission shaft 41 adopts a special structure design, taking the force transmission shaft as a flexible hinge structure, specifically, the flexible hinge characteristic is realized by the rib 4121, the axial size of the rib 4121 is larger than the cross-sectional size, so as to ensure that the transverse bending stiffness K b of the rib 4121 is much lower than the axial tension-compression stiffness K p , so as to ensure that the axial tension-compression stiffness K p of the force transmission shaft 41 composed of the rib 4121 is much higher than the transverse bending stiffness K b . It should be noted that the stiffness level of the force transmission shaft 41 is much lower than that of the force sensor 43, so the stiffness characteristic of the force transmission structure 4 is determined by the force transmission shaft 41.

[0067] According to the force detection device of the present application, taking the measurement of the x-direction load F x as an example, the load in this direction is borne by three-direction force transmission structure 4, and the loads borne by the three-direction force transmission structure 4 are f x , f y and f z , respectively. Deformation occurs in the three-direction force transmission structure 4, among which the x-direction force transmission structure 4 occurs axial deformation, and the y-direction and z-direction force transmission structure 4 occurs transverse bending deformation along the x-direction. Since the three-way orthogonal force transmission structure 4 is connected together through the friction block base 2, the axial deformation of the x-direction force transmission structure 4 and the transverse bending deformation of the y-direction and z-direction force transmission structure 4 along the x-direction are of the same size, which is defined as d x , so there are

[0068] f x = K p d x

[0069] f y = f z = K b d x

[0070]

[0071] Obviously, F x with f x The error between them is determined by the decoupling degree γ, when the lateral bending stiffness K of the force transmission shaft 41 b Less than axial tensile / compressive stiffness K p When 1%, i.e., γ > 100, F x ≈f x At this time, the force transmission structure 4 in the y and z directions has a lateral bending stiffness K. b The axial tensile and compressive stiffness K of the force transmission structure 4 in the x-direction is much lower. p Therefore, the load shared by the force transmission structure 4 in the y and z directions is much lower than that in the force transmission structure 4 in the x direction, thus enabling the measurement accuracy to be controlled by controlling the decoupling degree γ.

[0072] Further, see Figure 4 The friction block base 2 includes two second support panels 21 and one third support panel 22. The two second support panels 21 and the third support panel 22 are orthogonal to each other and are fixedly connected to each other at their side edges, forming a corner of a cube. The surface facing inward of the corner is the inner surface, and the surface opposite the inner surface is the outer surface. Each second support panel 21 is provided with a threaded through hole for connection with the force transmission structure 4. The inner surface of the third support panel 22 has four threaded holes for mounting the friction block 3, and the outer surface has threaded holes corresponding to the central axis of the force transmission structure 4 for connection with the force transmission structure 4.

[0073] See Figure 1 The mounting base 1 includes three first support panels 11 that are orthogonal to each other. The three first support panels 11 are parallel to one of the two second support panels 21 and the third support panel 22, respectively; the three first support panels 11 are each provided with a plurality of circumferentially arranged threaded holes for mounting the force transmission structure 4.

[0074] The structure of friction block 3 is shown in the figure. Figure 5 Friction block 3, as a stationary component of the friction pair, contacts the crown contact surface of the turbine blade. Friction block 3 is a test piece, and its material is determined according to the test requirements. The bottom of friction block 3 has four threaded through holes, which correspond to the four threaded holes on the inner surface of the third support panel 22 of the friction block base 2, respectively. When installing friction block 3, screws are screwed into the four threaded holes on the inner surface of the third support panel 22 of the friction block base 2 after passing through the threaded through holes of friction block 3, thereby achieving installation and fixation.

[0075] See Figures 1-3The friction block 3 is arranged on the inner surface of the third support panel 22. The three force transmission structures 4 are respectively vertically and fixedly connected with one of the two second support panels 21 and the third support panel 22. The force transmission structure 4 and the friction block base 2 are connected together by the stud bolt 5.

[0076] Specifically, each force transmission structure 4 comprises a force transmission shaft 41, a first force sensor adapter disc 42, a force sensor 43 and a second force sensor adapter disc 44. One end of the three force transmission shafts 41 is fixedly connected with the outer surface of the two second support panels 21 or the third support panel 22 by the stud bolt 5, and the axis of the force transmission shaft 41 is perpendicular to the outer surface of the two second support panels 21 or the third support panel 22. The other end of the force transmission shaft 41 is fixedly connected with the first force sensor adapter disc 42, the first force sensor adapter disc 42 is fixedly connected with one end of the force sensor 43, and the other end of the force sensor 43 is fixedly connected with the second force sensor adapter disc 44, so that the second force sensor adapter disc 44 is fixedly connected on the first support panel 11 of the mounting base 1.

[0077] Referring to Figures 6-9 The force transmission shaft 41 is a hollow shaft structure, and the force transmission shaft 41 is divided into a first part 411, a second part 412 and a third part 413 in the axial direction. The first end of the first part 411 is fixedly connected with the friction block base 2 by the stud bolt 5, the first end of the second part 412 is fixedly connected with the second end of the first part 411, and the second end of the second part 412 is fixedly connected with the first end of the third part 413. The second end of the third part 413 of the force transmission shaft 41 is fixedly connected with the first force sensor adapter disc 42.

[0078] Further, the outer diameter of the first part 411 and the second part 412 is the same and smaller than the outer diameter of the third part 413, and the inner diameter of the second part 412 and the third part 413 is the same and larger than the inner diameter of the first part 411.

[0079] Further, the second part 412 of the force transmission shaft 41 is a plurality of circumferentially distributed ribs 4121. The ribs 4121 of the force transmission shaft 41 are uniformly arranged in the circumferential direction, so as to ensure that the stiffness of the force transmission shaft 41 in each direction is uniform.

[0080] Referring to Figure 8 The cross section of the rib 4121 is approximately fan ring shape, and the gap between the ribs 4121 is the minimum value allowed by the processing technology, preferably in the range of 1-3mm. In one force detection device of the present application, the size of the rib 4121 of the force transmission shaft 41 determines the transverse bending stiffness K b and the axial tension and compression stiffness K p and the decoupling degree γ of the force transmission shaft 41, and the size of the rib 4121 can be determined according to the required transverse bending stiffness K band axial tension and compression stiffness K p and decoupling degree γ.

[0081] Decoupling degree γ can be calculated according to theoretical formula. Based on the formula, the lateral bending stiffness K b and axial tension and compression stiffness K p and decoupling degree γ, the more the number of ribs 4121, the higher the lateral bending stiffness K b and axial tension and compression stiffness K p . In the case of the size of the rib 4121 is determined, the number n of the rib 4121 depends on the diameter of the force transmission shaft 41 and the gap size between different ribs 4121, and the gap size depends on the processing technology, in the case of the processing technology allows, the smaller the gap between the ribs 4121, the more the number of ribs 4121, the higher the lateral bending stiffness K b and axial tension and compression stiffness K p , so the structural stiffness of the measuring device is higher.

[0082] Further, the relationship between the cross-sectional area A n and the length L satisfies the following relationship:

[0083]

[0084] Referring to Figure 6 , Figure 8 and Figure 9 , the third part 413 is provided with a plurality of mounting through holes 4131, the plurality of mounting through holes 4131 extend along the axial direction of the force transmission shaft 41 and are uniformly distributed in the circumferential direction. The mounting through holes 4131 are used for connection between the first force sensor adapter plate 42. The structure of the second force sensor adapter plate 44 is the same as that of the first force sensor adapter plate 42, and is used for fixedly connecting the force sensor 43 to the first support panel 11.

[0085] The force transmission shaft 41 can be made of bar or pipe. First, the outer circumferential surface of the first part 411, the second part 412 and the third part 413 is turned, then the central through hole of the first part 411 is drilled and / or reamed, and then the inner surface of the second part 412 and the third part 413 is obtained by reaming or milling, then a plurality of axially extending and circumferentially uniformly distributed opening grooves are cut on the second part 412 by wire cutting or milling or other cutting processes, so that the second part 412 becomes a structure surrounded by a plurality of circumferentially uniformly distributed ribs 4121, and finally a plurality of mounting through holes 4131 are formed on the third part 413 by milling.

[0086] The force detection device of the present application, the lateral bending stiffness K band axial tension-compression stiffness K p determines the mechanical properties of the force transmission structure 4, the transverse bending stiffness K b and axial tension-compression stiffness K p The smaller the ratio, the smaller the force dimension coupling effect between different direction force transmission structures 4, that is, the higher the decoupling degree γ, the smaller the force dimension coupling effect, and the higher the measurement accuracy of the contact force of the shroud contact surface.

[0087] A force detection device of the present application, the friction block 3 is fastened and connected on the friction block base 2, three force transmission structures 4 are arranged orthogonally and connected together with the friction block base 2 and the mounting base 1 respectively. The friction block 3 serves as the static part of the friction pair, bears the contact force of the relative motion between the friction pairs and transmits the contact force to the friction block base 2, and then transmits the load to the force transmission structure 4, and measures the axial load size through the force sensor 43.

[0088] Compared with the prior art, the force detection device provided by the embodiment effectively reduces the force dimension coupling effect of three-direction contact force measurement and improves the measurement accuracy by adopting the flexible hinge structure designed force transmission shaft 41; the three-direction orthogonal arrangement of the force transmission structure 4 is connected together through the friction block base 2, so that the friction block 3 is extended, the accessibility of the friction block 3 is ensured, the friction pair static part for small size structures such as the shroud contact surface of the turbine blade of the aero-engine is provided, and the contact force of the contact interface is measured; the three-direction force transmission structure 4 is connected together through the friction block base 2 to provide stiffness for the friction block 3, so that sufficient structural stiffness is provided for the friction block 3 under the condition of ensuring that the size of the friction block 3 is small and accessible.

[0089] Embodiment 2

[0090] On the basis of embodiment 1, the embodiment 2 of the present application adopts a different force transmission shaft 41', as shown in Figures 10-13 .

[0091] The force transmission shaft 41' includes a first part 411', a second part 412' and a third part 413', wherein the first part 411' is a disc, the center of the disc has a first through hole, a plurality of second through holes are arranged near the outer circumference, and the plurality of second through holes are uniformly distributed in the circumferential direction. Among them, the first through hole is used for fixed connection with the friction block base 2, and the second through hole is used for mounting the rib 4121'.

[0092] The third part 413' is a larger disc than the first part 411', the center part has a third through hole, a plurality of fourth through holes are arranged on the outer circumference of the third through hole to form a circle, and a plurality of mounting through holes 4131' are arranged on the outer circumference of the fourth through hole to form a circle. The fourth through hole is used for connecting the rib 4121', and the mounting through hole 4131' is used for fixed connection with the first force sensor adapter disc 42.

[0093] The second part 412' comprises a plurality of ribs 4121', each of which has a circular cross section. The two ends of each rib 4121' are inserted into the second through hole of the first part 411' and the fourth through hole of the third part 413', respectively. The two ends of each rib 4121' are fixedly connected, which can be achieved by screw connection, interference fit connection or other conventional fixed connection methods.

[0094] In some embodiments, the cross section of the rib 4121' can also be trapezoidal, rectangular or any other suitable shape. For different cross-sectional shapes of the rib 4121', the cross-sectional area A of the rib 4121' and the length L should satisfy the formula n The same formula should be satisfied between the cross-sectional area A of the rib 4121' and the length L

[0095]

[0096] The lateral bending stiffness K of the force transmission shaft 41' with ribs 4121' of different cross-sectional shapes is further ensured to be b much lower than the axial tensile and compressive stiffness K p The lateral bending stiffness K of the force transmission shaft 41' with ribs 4121' of different cross-sectional shapes is further ensured to be b much lower than the axial tensile and compressive stiffness K p which can be determined by finite element analysis.

[0097] By using the technical solution of the second embodiment, the force transmission shaft 41' has a simple structure and is easy to process and assemble, thereby reducing the production cost while ensuring the measurement accuracy.

[0098] Embodiment 3

[0099] The present application also relates to a method for testing the mechanical properties of the shroud contact interface of a turbine blade of an aero-engine, which uses the force detection device of embodiment 1 or embodiment 2.

[0100] The testing method comprises the following steps:

[0101] S1: mounting and fixing the blade root position of the turbine blade of the aero-engine on the clamp of the test bench;

[0102] S2: mounting the force detection device of embodiment 1 or embodiment 2 on the corresponding position of the test bench;

[0103] S3: abutting the friction block 3 of the force detection device against the contact surface of the shroud of the turbine blade of the aero-engine;

[0104] S4: applying excitation to the turbine blade of the aero-engine and recording the data fed back by the force sensor 43 in the force detection device;

[0105] S5: calculating the data to analyze the mechanical characteristic parameters of the contact interface of the turbine blade of the aero-engine.

[0106] Further, in step S2, one or two force detection devices can be selected and installed.

[0107] Further, in step S3, the data fed back by the force sensor 43 perpendicular to the surface of the friction block 3 is between 0.1N and 0.2N, and when this condition is met, it indicates that the contact between the friction block 3 and the contact surface of the shroud is good, neither too loose to obtain effective data nor too tight to obtain inaccurate data.

[0108] Further, in step S4, the excitation applied to the turbine blade of the aero-engine is vibration excitation.

[0109] Referring to Figures 14-16 , first, the blade root position of the turbine blade 6 of the aero-engine is fixedly installed on the clamp of the test bench (not shown in the figure), and then a force detection device is installed at the corresponding position on the test bench according to the scene requirements. The test device of the present application is arranged at the shroud position of the turbine blade 6 of the aero-engine. According to the test requirements, one test device of the present application can be selected to measure the selected contact surface, or two test devices of the present application can be arranged to measure the contact forces of two contact surfaces respectively.

[0110] The friction block 3 is in contact with the shroud contact surface of the turbine blade 6 of the aero-engine, specifically, the third support panel 22 of the friction block base 2 is parallel to the shroud contact surface of the turbine blade 6 of the aero-engine, the two second support panels 21 are respectively parallel or perpendicular to the axial direction of the turbine blade 6 of the aero-engine, and the opening direction of the mounting base 1 is towards the direction of the blade root of the turbine blade 6 of the aero-engine. The first support panel 11 of the mounting base 1 is fixedly installed on the test bench, and the specific connection mode can be determined according to the structure of the test bench, which does not affect the application effect.

[0111] Taking the arrangement of two test devices of the present application as an example, two test devices of the present application measure the contact forces of the shroud contact surface of the turbine blade 6 of the aero-engine. When the turbine blade 6 of the aero-engine vibrates under the excitation, the contact surface between the friction block 3 and the turbine blade 6 of the aero-engine will move relatively and generate a contact force, which is measured by the force sensor 43 of the test device of the present application, so as to obtain the contact force signal of the shroud contact surface of the turbine blade 6 of the aero-engine when it vibrates under the excitation, and analyze the mechanical characteristics of the contact interface.

[0112] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A force detecting device characterized by comprising: The system includes a mounting base, a friction block, a friction block base, and three force transmission structures. The central axes of the three force transmission structures are orthogonal to each other, and one end of each force transmission structure near the intersection of the central axes is fixedly connected to the friction block base. The other end of each force transmission structure is fixedly connected to a first support panel of the mounting base. The friction block is disposed on the friction block base. Each force transmission structure includes a force transmission shaft, which is a hollow shaft structure. The force transmission shaft is divided into a first part, a second part, and a third part along the axial direction. The first end of the first part is fixedly connected to the friction block base, the first end of the second part is fixedly connected to the second end of the first part, and the second end of the second part is fixedly connected to the first end of the third part. The outer diameters of the first part and the second part are the same and smaller than the outer diameter of the third part, and the inner diameters of the second part and the third part are the same and larger than the inner diameter of the first part. The second part of the force transmission shaft consists of multiple circumferentially distributed ribs. The transverse bending stiffness of the force transmission shaft is... Less than or equal to axial tensile and compressive stiffness 1%; Each of the force transmission structures further includes a first force sensor adapter disk, a second force sensor adapter disk, and a force sensor. The second end of the third part of the force transmission shaft is fixedly connected to the first force sensor adapter disk. The first force sensor adapter disk is fixedly connected to one end of the force sensor, and the other end of the force sensor is fixedly connected to the second force sensor adapter disk.

2. The force detection device according to claim 1, wherein The friction block base further comprises two second support panels and a third support panel which are perpendicular to each other; the friction block is arranged on the surface of the third support panel facing the two second support panels; the three force transmission structures are vertically and fixedly connected with one of the two second support panels and the third support panel respectively.

3. The force detection device of claim 2, wherein The cross section of the rib is any one of a fan ring shape, a trapezoidal shape, a rectangular shape or a circular shape.

4. The force detection device of claim 3, wherein The gap size between the ribs is in the range of 1-3 mm.

5. A force detection device according to any one of claims 1-4, characterized in that The third part is provided with a plurality of mounting through holes which axially extend and are uniformly distributed in the circumferential direction.

6. A method of testing the mechanical characteristics of a shroud contact interface of a turbine blade of an aeroengine, characterized in that, Use a force detection device according to any one of claims 1-5.

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