A strain piezoelectric composite rotor balance

Abstract

The present invention discloses a strain piezoelectric composite rotor balance, belonging to the technical field of wind tunnel tests; it includes a floating frame, a fixed frame and a force-sensitive unit; the force-sensitive unit is arranged between the floating frame and the fixed frame; the force-sensitive unit is provided with a strain force sensor, a piezoelectric force sensor, a decoupling link and a slider capable of adjusting the pre-tightening force; this solution uses the characteristics of high static measurement accuracy of the strain force sensor and wide dynamic measurement frequency band of the piezoelectric force sensor, as well as the decoupling effect of the decoupling link to achieve simultaneous high-precision measurement of the static load and high-frequency vibration load of the rotor.

Description

Technical Field

[0001] The present invention relates to the technical field of wind tunnel tests, and particularly relates to a strain piezoelectric composite rotor balance. Background Art

[0002] Wind tunnel tests are an important means for carrying out rotor aerodynamic performance evaluation and new rotor aerodynamic layout design, and play an important role in the development process of rotor aircraft. When conducting wind tunnel tests on rotor aerodynamic performance, a rotor balance is usually used to measure the load of the rotor and obtain parameters such as the pull force and power of the rotor.

[0003] When conducting certain special rotor performance wind tunnel tests, it is necessary to measure not only the static load (0th order value) of the rotor, but also the 2Nth order high-frequency harmonic load (N is the number of rotor blades) to evaluate the vibration characteristics of the rotor. Therefore, requirements are put forward for the dynamic measurement ability of the rotor balance.

[0004] Patent document CN111175014A discloses a balance system and method for accurate measurement of rotor aerodynamic loads. This solution is the most commonly used rotor balance system solution at present, and a plurality of strain force sensors are used to form a force measurement system. The strain force sensor has good measurement effects on static and low-frequency signals, but has poor measurement effects on high-frequency signals, and may generate gain errors and phase drifts. Therefore, the conventional rotor balance has good effects when measuring static and low-frequency rotor load signals, but has large measurement errors when measuring high-frequency rotor load signals, and cannot meet the measurement requirements of high-frequency rotor vibration loads. Summary of the Invention

[0005] The purpose of the present invention is to provide a strain piezoelectric composite rotor balance for the above-mentioned deficiencies, which solves the problem that the existing conventional rotor balance has large measurement errors when measuring high-frequency rotor load signals and cannot meet the measurement requirements of high-frequency rotor vibration loads.

[0006] The present invention is realized through the following scheme:

[0007] A strain piezoelectric composite rotor balance includes a floating frame, a fixed frame, and a force-sensitive unit; the force-sensitive unit is arranged between the floating frame and the fixed frame, and a main connecting plate and an auxiliary connecting plate connected to at least one group of force-sensitive units are respectively arranged on the floating frame and the fixed frame; a strain force sensor, a piezoelectric force sensor, a decoupling link, and a slider capable of adjusting the pre-tightening force are arranged in the force-sensitive unit.

[0008] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, a first assembly hole is provided at the central position of the floating frame, and a second assembly hole adapted to the position of the first assembly hole is provided on the fixed frame. A rotor balance coordinate system OXYZ is established with the central position of the line connecting the first assembly hole and the second assembly hole as the origin; the OX axis is along the length direction of the floating frame and coincides with the axis of the X-direction force-sensitive unit; the OZ axis is along the width direction of the floating frame and coincides with the midline of the axes of the two groups of Z-direction force-sensitive units; the OY axis is along the center line direction of the first assembly hole and the second assembly hole; four groups of force-sensitive units are arranged along the Y direction, and the four groups of force-sensitive units are symmetrically arranged with respect to the reference planes XOY and YOZ; two groups of force-sensitive units are arranged along the Z direction, and the two groups of force-sensitive units are symmetrically arranged with respect to the reference plane YOZ; one group of force-sensitive units is arranged along the X direction.

[0009] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, the main connecting plate and the auxiliary connecting plate respectively support two groups of force-sensitive units along the Z direction and one group of force-sensitive units along the X direction; three main connecting plates are provided, namely the first main connecting plate, the second main connecting plate and the third main connecting plate; three auxiliary connecting plates are provided, namely the first auxiliary plate, the second auxiliary plate and the third auxiliary plate.

[0010] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, the first main connecting plate and the first auxiliary plate are correspondingly arranged to form a first Z-direction support part; the second main connecting plate and the second auxiliary plate are correspondingly arranged to form a second Z-direction support part, and the first Z-direction support part and the second Z-direction support part are symmetrically arranged with respect to the reference plane YOZ; the third main connecting plate and the third auxiliary plate are correspondingly arranged to form a first X-direction support part; the connecting line direction of the third main connecting plate and the third auxiliary plate is collinear with the X-axis direction.

[0011] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, a first connection hole connected to the force-sensitive unit is provided on the floating frame or the main connecting plate, and a second connection hole connected to the force-sensitive unit is provided on the fixed frame or the auxiliary connecting plate; the force-sensitive unit specifically includes a strain force sensor, a first nut, a decoupling link, a second nut, a piezoelectric force sensor, a slider and a first screw; a gasket is provided on the first screw, a through hole for the first screw to pass through is provided on the slider, the first screw passes through the first connection hole and the slider and then is connected to the piezoelectric force sensor, the decoupling link is respectively connected to the piezoelectric force sensor and the strain force sensor, the connection part of the decoupling link and the strain force sensor is locked by the first nut, and the connection part of the decoupling link and the piezoelectric force sensor is locked by the second nut.

[0012] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, the slider includes a chute body, a wedge block, and a second screw; a chute cavity for cooperating with the wedge block is provided in the chute body, and a cooperation hole connected to the second screw is provided on the side wall of the chute body; the second screw passes through the cooperation hole and contacts the side wall of the wedge block.

[0013] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, the chute body specifically includes a first side plate, a second side plate, a third side plate, a main side plate, and a support plate; the first side plate, the second side plate, the third side plate, and the main side plate are connected end to end to form a cavity structure with openings at both ends, the main side plate is symmetrically arranged with the second side plate, the first side plate and the third side plate are symmetrically arranged, the support plate is arranged at one end of the cavity structure, the main side plate protrudes from the first side plate, the second side plate, and the third side plate, the thickness of the support plate gradually increases along the direction from the main side plate to the second side plate, so that the chute cavity forms a wedge-shaped cavity, and a chute hole for the first screw to pass through is provided at the center of the support plate.

[0014] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, the wedge block includes a wedge block inclined surface and a wedge block vertical surface; the inclined surface angle of the wedge block inclined surface is within the equivalent friction angle of the inclined surface angle of the inner inclined surface of the support plate, and the wedge block inclined surface and the inner inclined surface of the support plate are in contact, the wedge block vertical surface is in contact with the inner side walls of the first side plate and the third side plate, and a wedge block hole for the first screw to penetrate is also provided on the wedge block inclined surface; the size of the wedge block hole is adapted to the size of the first screw, and the first screw passes through the wedge block hole and the chute hole.

[0015] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, the first screw includes a cylindrical surface and a threaded surface; the cylindrical surface forms a small clearance fit with the wedge block hole, and the threaded surface is arranged at the bottom position of the cylindrical surface; the decoupling link includes an external threaded section, a contraction section, and an internal threaded section; the external threaded section and the internal threaded section are respectively arranged on both sides of the contraction section, and the central axes of the external threaded section, the contraction section, and the internal threaded section are collinear, and the diameter of the contraction section is not greater than the diameter of the external threaded section or the internal threaded section.

[0016] Based on the structure of the above-mentioned strain piezoelectric composite rotor balance, through the decoupling action of the decoupling link, four groups of force-sensitive units arranged in the Y direction sense and measure the longitudinal force Y, Mz, and Mx component loads; two groups of force-sensitive units arranged in the Z direction sense and measure the transverse force Z and My component loads; one group of force-sensitive units arranged in the X direction sense and measure the axial force X component load.

[0017] Therefore, the composite rotor balance can measure the loads of 6 components of the rotor, and the corresponding relationship between the 6-component loads and the output signals of each strain force sensor is:

[0018] (1)

[0019] The corresponding relationship between the six-component load and the output signals of each piezoelectric force sensor is as follows:

[0020] (2)

[0021] In the formula:

[0022] Y, X, Mz, Z, My, Mx - balance components;

[0023] Subscript "SG" - signal of the strain-type force sensor;

[0024] Subscript "PZ" - signal of the piezoelectric force sensor;

[0025] - the force sensor of the i-th group of force-sensitive units.

[0026] According to formula (1), the static load (0th order value) of the rotor can be obtained; according to formula (2), the 2Nth order high-frequency harmonic load of the rotor can be obtained. That is, the simultaneous high-precision measurement of the static load and high-frequency vibration load in some special rotor tests is realized.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0028] 1. This solution proposes to set a total of seven groups of force-sensitive units on a rotor balance. Each group of force-sensitive units includes a strain-type force sensor, a piezoelectric force sensor, and a decoupling link. By using the characteristics of high static measurement accuracy of the strain-type force sensor, wide dynamic measurement frequency band of the piezoelectric force sensor, and the decoupling effect of the decoupling link, the simultaneous high-precision measurement of the six-component static load and high-frequency vibration load of the rotor is realized.

[0029] 2. In this composite rotor balance solution, by adjusting the height of the slider, the pre-tightening force of each component of the force-sensitive unit is precisely adjusted to ensure that the decoupling link does not bend or twist, and only transmits the load along its own axis, reducing the interference caused by force transmission and improving the measurement effect of the rotor balance. Brief Description of the Drawings

[0030] Figure 1 is a three-dimensional structural schematic diagram of the composite rotor balance of this solution;

[0031] Figure 2 is a schematic diagram of the positions of the main connecting plate and the auxiliary connecting plate in this solution;

[0032] Figure 3 is a cross-sectional structural schematic diagram of the force-sensitive unit in this solution;

[0033] Figure 4Schematic three-dimensional structure diagram of the first screw in this solution;

[0034] Figure 5 Schematic three-dimensional structure diagram of the decoupling link in this solution;

[0035] Figure 6 Schematic three-dimensional structure diagram of the slider in this solution;

[0036] Figure 7 Schematic sectional three-dimensional structure diagram of the slider in this solution;

[0037] Figure 8 Schematic sectional structure diagram of the slider in this solution;

[0038] Figure 9 Schematic layout diagram of the strain gauge sensor and the piezoelectric force sensor in this solution;

[0039] Reference numerals: 1. floating frame; 2. fixed frame; 3. force-sensitive unit; 4. main connecting plate; 5. auxiliary connecting plate; 11. first assembly hole; 21. second assembly hole; 31. strain gauge force sensor; 32. first nut; 33. decoupling link; 34. second nut; 35. piezoelectric force sensor; 36. slider; 37. first screw; 38. gasket; 41. first main connecting plate; 42. second main connecting plate; 43. third main connecting plate; 51. first auxiliary plate; 52. second auxiliary plate; 53. third auxiliary plate; 371. threaded surface; 372. cylindrical surface; 331. external thread section; 332. contraction section; 333. internal thread section; 361. chute body; 362. wedge block; 363. second screw; 364. chute cavity; 365. mating hole; 3611. first side plate; 3612. second side plate; 3613. third side plate; 3614. main side plate; 3615. support plate; 3616. chute hole; 3621. wedge block inclined surface; 3622. wedge block vertical surface; 3623. wedge block hole; 1001. first strain gauge force sensor; 1002. second strain gauge force sensor; 1003. third strain gauge force sensor; 1004. fourth strain gauge force sensor; 1005. fifth strain gauge force sensor; 1006. sixth strain gauge force sensor; 1007. seventh strain gauge force sensor; 2001. first piezoelectric force sensor; 2002. second piezoelectric force sensor; 2003. third piezoelectric force sensor; 2004. fourth piezoelectric force sensor; 2005. fifth piezoelectric force sensor; 2006. sixth piezoelectric force sensor; 2007. seventh piezoelectric force sensor. Detailed implementation manners

[0040] All features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any manner.

[0041] Any feature disclosed in this specification (including any additional claims and abstract), unless specifically recited, may be replaced by other equivalent or alternative features with similar purposes. That is, unless specifically recited, each feature is only an example of a series of equivalent or similar features.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 predetermined orientation, be constructed and operated in a predetermined orientation, and therefore should not be construed as a limitation to the present invention.

[0043] In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features.

[0044] Embodiment 1

[0045] As Figures 1 to 8 The present invention provides a technical solution:

[0046] A strain piezoelectric composite rotor balance, including at least but not limited to a floating frame 1, a fixed frame 2, and a force-sensitive unit 3; the force-sensitive unit 3 is arranged between the floating frame 1 and the fixed frame 2, and a main connecting plate 4 and an auxiliary connecting plate 5 connected to at least one group of force-sensitive units 3 are respectively arranged on the floating frame 1 and the fixed frame 2. A strain force sensor 31, a piezoelectric force sensor 35, and a slider 36 capable of adjusting the pre-tightening force are arranged in the force-sensitive unit 3.

[0047] Based on the above structure, by arranging multiple groups of force-sensitive units 3 between the floating frame 1 and the fixed frame 2, the component forces in multiple directions can be sensitively measured. By arranging the main connecting plate 4 and the auxiliary connecting plate 5 on the floating frame 1 and the fixed frame 2, a connection basis can be provided for the force-sensitive units 3 that are not directly connected to the floating frame 1 and the fixed frame 2. A strain force sensor 31 and a piezoelectric force sensor 35 are arranged on each group of force-sensitive units 3. By using the characteristics of high static measurement accuracy of the strain force sensor 31 and wide dynamic measurement frequency band of the piezoelectric force sensor 35, the simultaneous high-precision measurement of the static load and high-frequency vibration load of the rotor is realized.

[0048] In this solution, the main connection plate and the auxiliary connection plate are arranged in pairs, with at least three pairs, for installing the Z-component, X-component, and My-component force-sensitive units. The main connection plate and the floating frame can be one part, machined integrally; or they can be two parts, machined separately. The auxiliary connection plate and the fixed frame can be one part, machined integrally; or they can be two parts, machined separately.

[0049] As an example, a first assembly hole 11 is provided at the central position on the floating frame 1, a second assembly hole 21 adapted to the position of the first assembly hole 11 is provided on the fixed frame 2, and a rotor balance coordinate system OXYZ is established between the first assembly hole 11 and the second assembly hole 21; the OX axis is along the length direction of the floating frame 1 and coincides with the axis of the X-direction force-sensitive unit; the OZ axis is along the width direction of the floating frame 1 and coincides with the midline of the axes of the two groups of Z-direction force-sensitive units; the OY axis is along the center line direction of the first assembly hole 11 and the second assembly hole 21.

[0050] Four groups of force-sensitive units 3 are arranged along the Y direction, and the four groups of force-sensitive units 3 are symmetrically arranged with respect to the reference planes XOY and YOZ, sensing the longitudinal force Y, Mz, and Mx components; two groups of force-sensitive units 3 are arranged along the Z direction, and the two groups of force-sensitive units 3 are symmetrically arranged with respect to the reference plane YOZ, sensing the transverse forces Z and My components; one group of force-sensitive units 3 is arranged along the X direction, sensing the axial force X component.

[0051] Based on the above structure, in this solution, multiple groups of force-sensitive units 3 are respectively arranged between the floating frame 1 and the fixed frame 2 along the X, Y, and Z axes, and the longitudinal force Y, Mz, and Mx components, the transverse forces Z and My components, and the axial force X component are respectively measured by the force-sensitive units 3.

[0052] As an example, the main connection plate 4 and the auxiliary connection plate 5 respectively provide support for two groups of force-sensitive units along the Z direction and one group of force-sensitive units along the X direction.

[0053] The main connection plate 4 is provided with three, namely the first main connection plate 41, the second main connection plate 42, and the third main connection plate 43.

[0054] The auxiliary connection plate 5 is provided with three, namely the first auxiliary plate 51, the second auxiliary plate 52, and the third auxiliary plate 53.

[0055] The first main connection plate 41 and the first auxiliary plate 51 are correspondingly arranged to form a first Z-direction support portion; the second main connection plate 42 and the second auxiliary plate 52 are correspondingly arranged to form a second Z-direction support portion; the first Z-direction support portion and the second Z-direction support portion are symmetrically arranged with respect to the reference plane YOZ; the third main connection plate 43 and the third auxiliary plate 53 are correspondingly arranged to form a first X-direction support portion, and the connection direction of the third main connection plate 43 and the third auxiliary plate 53 is collinear with the X axis of the coordinate system.

[0056] Based on the above structure, a more refined connection structure is provided in this solution. By arranging the force-sensitive unit 3 in the first Z-direction support part and the second Z-direction support part, the transverse force Z and My components are measured. By arranging the force-sensitive unit 3 in the first X-direction support part, the axial force X component is measured.

[0057] As an example, a first connection hole connected to the force-sensitive unit 3 is arranged on the floating frame 1 or the main connection plate 4, and a second connection hole connected to the force-sensitive unit 3 is arranged on the fixed frame 2 or the auxiliary connection plate 5.

[0058] Based on the above structure, the force-sensitive unit 3 is stably fixed between the floating frame 1 and the fixed frame 2 through the first connection hole and the second connection hole.

[0059] As an example, the force-sensitive unit 3 may specifically include a strain-type force sensor 31, a first nut 32, a decoupling link 33, a second nut 34, a piezoelectric force sensor 35, a slider 36, and a first screw 37; a gasket 38 is arranged on the first screw 37; a through hole for the first screw 37 to penetrate is arranged on the slider 36. The first screw 37 passes through the first connection hole and the slider 36 and then is connected to the piezoelectric force sensor 35. The decoupling link 33 is respectively connected to the piezoelectric force sensor 35 and the strain-type force sensor 31; the connection part between the decoupling link 33 and the strain-type force sensor 31 is locked by the first nut 32, and the connection part between the decoupling link 33 and the piezoelectric force sensor 35 is locked by the second nut 34.

[0060] Based on the above structure, the strain-type force sensor 31, the first nut 32, the decoupling link 33, the second nut 34, the piezoelectric force sensor 35, the slider 36, the first screw 37, and the gasket 38 are connected in series in sequence; the strain-type force sensor 31 and the piezoelectric force sensor 35 are arranged at both ends of the decoupling link 33; the force transmission path of the rotor load on the force-sensitive unit 3 is: floating frame 1 → slider 36 → piezoelectric force sensor 35 → decoupling link 33 → strain-type force sensor 31 → fixed frame 2; thus, the rotor static load is sensed by the strain-type force sensor 31, and the rotor dynamic load is sensed by the piezoelectric force sensor 35, realizing the simultaneous high-precision measurement of the rotor static load and the high-frequency vibration load.

[0061] As an example, the slider 36 includes a chute body 361, a wedge block 362, and a second screw 363; a chute cavity 364 for cooperating with the wedge block 362 is arranged in the chute body 361; a mating hole 365 connected to the second screw 363 is arranged on the side wall of the chute body 361, and the second screw 363 passes through the mating hole 365 and contacts the side wall of the wedge block 362.

[0062] The chute body 361 specifically includes a first side plate 3611, a second side plate 3612, a third side plate 3613, a main side plate 3614, and a support plate 3615; the first side plate 3611, the second side plate 3612, the third side plate 3613, and the main side plate 3614 are connected end to end to form a cavity structure with openings at both ends. The main side plate 3614 and the second side plate 3612 are symmetrically arranged, and the first side plate 3611 and the third side plate 3613 are symmetrically arranged. The support plate 3615 is arranged at one end of the cavity structure. The main side plate 3614 protrudes from the first side plate 3611, the second side plate 3612, and the third side plate 3613. Along the direction from the main side plate 3614 to the second side plate 3612 on the support plate 3615, the thickness of the support plate 3615 gradually increases, so that the chute cavity 364 forms a wedge-shaped cavity; a chute hole 3616 for the first screw 37 to pass through is provided at the center of the support plate 3615, and the chute hole 3616 is an oblong hole.

[0063] The wedge 362 may include a wedge inclined surface 3621 and a wedge vertical surface 3622; the inclined surface angle of the wedge inclined surface 3621 and the inclined surface angle of the inner inclined surface of the support plate 3615 are within the equivalent friction angle, and the wedge inclined surface 3621 is in contact with the inner inclined surface of the support plate 3615. The wedge vertical surface 3622 is in contact with the inner side walls of the first side plate 3611 and the third side plate 3613. A wedge hole 3623 for the first screw 37 to penetrate is further provided on the wedge inclined surface 3621. The size of the wedge hole 3623 is adapted to the size of the first screw 37, and the first screw 37 passes through the wedge hole 3623 and the chute hole 3616.

[0064] Based on the above structure, in this solution, since the inclined surface angle of the wedge inclined surface 3621 and the inclined surface angle of the inner inclined surface of the support plate 3615 are within the equivalent friction angle, it has a self-locking function. When subjected to an axial force (along the axis direction of the wedge hole 3623), the wedge 362 will not slide along the chute cavity 364. Therefore, the height of the slider 36 remains unchanged, ensuring that the components of the force-sensitive unit 3 are tightly connected without looseness. The height of the slider 36 in this solution is achieved by adjusting the position of the wedge 362, and the wedge 362 can only move along the length direction of the chute in the chute cavity 364, and its position is accurately adjusted by the second screw 363.

[0065] As an example, the first screw 37 may include a cylindrical surface 372 and a threaded surface 371; the cylindrical surface 372 and the wedge hole 3623 form a small clearance fit, and the threaded surface 371 is arranged at the bottom position of the cylindrical surface 372.

[0066] The first screw 37 passes through the first connection hole, the chute hole 3616, and the wedge block hole 3623 on the floating frame 1 and is threadedly connected to the piezoelectric force sensor 35. The upper end of the decoupling link 33 is connected to the piezoelectric force sensor 35 through the external thread section 331 and is fastened with the second nut 34. The lower end of the decoupling link 33 is connected to the strain force sensor 31 through the internal thread section 333 and is fastened with the first nut 32.

[0067] Based on the above structure, the force-sensitive unit 3 organically connects the piezoelectric force sensor 35 and the strain force sensor 31 as a whole through the first screw 37 and the decoupling link 33, realizing the simultaneous measurement of the static load and vibration load of the rotor by the force-sensitive unit.

[0068] As an example, the decoupling link 33 may include an external thread section 331, a contraction section 332, and an internal thread section 333; the external thread section 331 and the internal thread section 333 are respectively arranged on both sides of the contraction section 332; the central axes of the external thread section 331, the contraction section 332, and the internal thread section 333 are collinearly arranged, and the diameter of the contraction section 332 is not greater than the diameter of the external thread section 331 or the internal thread section 333. The external thread section 331 is connected to the piezoelectric force sensor 35, and the internal thread section 333 is connected to the strain force sensor 31.

[0069] Specifically: the external thread section 331 is embedded in the piezoelectric force sensor 35 and is connected to the piezoelectric force sensor 35 through an external thread; the internal thread section 333 is sleeved on the end of the strain force sensor 31 and is connected to the strain force sensor 31 through an internal thread.

[0070] In this solution, by precisely adjusting the height of the slider 36, the pre-tightening force between the components of the force-sensitive unit 3 is adjusted to ensure reliable connection between the components. At the same time, the contraction section 332 of the decoupling link 33 does not bend or twist, avoiding additional force transmission interference and affecting the measurement accuracy of the rotor balance.

[0071] Based on the structure of the above-mentioned strain-piezoelectric composite rotor balance, through the decoupling effect of the decoupling link, four groups of force-sensitive units arranged along the Y direction sense and measure the longitudinal force Y, Mz, and Mx component loads; two groups of force-sensitive units arranged along the Z direction sense and measure the transverse force Z and My component loads; and one group of force-sensitive units arranged along the X direction sense and measure the axial force X component load.

[0072] The decoupling effect of the decoupling link in this solution is the same as the content and function disclosed in the patent No. CN111175014A, a balance system and method for accurate measurement of rotor aerodynamic loads, and will not be elaborated here.

[0073] Through the above structure, the compound rotor balance can measure the loads of six components of the rotor. The corresponding relationships between the six-component loads and the output signals of the respective strain type force sensors 31 are as follows:

[0074] (1)

[0075] The corresponding relationships between the six-component loads and the output signals of the respective piezoelectric type force sensors 35 are as follows:

[0076] (2)

[0077] In the formula:

[0078] Y, X, Mz, Z, My, Mx - balance components;

[0079] Subscript "SG" - strain type force sensor signal;

[0080] Subscript "PZ" - piezoelectric type force sensor signal;

[0081] - the force sensor of the i-th group of force-sensitive units.

[0082] According to formula (1), the static load (0th order value) of the rotor can be obtained, and according to formula (2), the 2N-th order high-frequency harmonic load of the rotor can be obtained. That is, the simultaneous high-precision measurement of the static load and the high-frequency vibration load of certain special rotor tests is realized; in Figure 9 1001 to 1007 respectively refer to the positions of the strain type force sensors of U1 SG ~U7 SG ; in Figure 9 2001 to 2007 respectively refer to the positions of the piezoelectric type force sensors of U1 PZ ~U7 PZ .

[0083] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A strain piezoelectric composite rotor balance, characterized in that: It includes a floating frame, a fixed frame and a force-sensitive unit; the force-sensitive unit is arranged between the floating frame and the fixed frame, and the floating frame and the fixed frame are respectively provided with a main connecting plate and an auxiliary connecting plate connected to at least one group of force-sensitive units; the force-sensitive unit is provided with a strain-type force sensor, a piezoelectric force sensor, a decoupling connecting rod and a slider capable of adjusting the preload force; the force-sensitive unit specifically includes a strain-type force sensor, a first nut, a decoupling connecting rod, a second nut, a piezoelectric force sensor, a slider and a first screw; the first screw is provided with a gasket, and the slider is provided with a spacer for the first screw to penetrate The first screw is connected to the piezoelectric force sensor after passing through the first connecting hole and the slider, the decoupling connecting rod is connected to the piezoelectric force sensor and the strain force sensor respectively, the connection between the decoupling connecting rod and the strain force sensor is locked by a first nut, and the connection between the decoupling connecting rod and the piezoelectric force sensor is locked by a second nut; the slider includes a slide groove body, a wedge block and a second screw; a slide groove cavity cooperating with the wedge block is provided in the slide groove body, and a cooperating hole connected with the second screw is provided on the side wall of the slide groove body; the second screw passes through the cooperating hole and contacts with the side wall of the wedge block.

2. A strain piezoelectric composite rotor balance according to claim 1, characterized in that: A first assembly hole is provided at the center position of the floating frame, and a second assembly hole matched with the position of the first assembly hole is provided on the fixed frame. A rotor balance coordinate system OXYZ is established with the center position of the line connecting the first assembly hole and the second assembly hole as the origin; the OX axis is along the length direction of the floating frame and coincides with the axis of the X-direction force sensitive unit; the OZ axis is along the width direction of the floating frame and coincides with the center line of the axes of the two groups of Z-direction force sensitive units; the OY axis is along the center line direction of the first assembly hole and the second assembly hole; four groups of force sensitive units are provided along the Y direction, and the four groups of force sensitive units are symmetrically arranged about the reference planes XOY and YOZ; two groups of force sensitive units are provided along the Z direction, and the two groups of force sensitive units are symmetrically arranged about the reference plane YOZ; and one group of force sensitive units is provided along the X direction.

3. A strain piezoelectric composite rotor balance according to claim 2, characterized in that: The main connecting plate and the auxiliary connecting plate provide support for two groups of force-sensitive units along the Z direction and one group of force-sensitive units along the X direction respectively; there are three main connecting plates, namely the first main connecting plate, the second main connecting plate and the third main connecting plate; there are three auxiliary connecting plates, namely the first auxiliary plate, the second auxiliary plate and the third auxiliary plate.

4. A strain piezoelectric composite rotor balance as claimed in claim 3, characterized in that: The first main connecting plate and the first auxiliary plate are arranged correspondingly to form a first Z-direction supporting portion; the second main connecting plate and the second auxiliary plate are arranged correspondingly to form a second Z-direction supporting portion, and the first Z-direction supporting portion and the second Z-direction supporting portion are symmetrically arranged along the reference plane YOZ; the third main connecting plate and the third auxiliary plate are arranged correspondingly to form a first X-direction supporting portion; the connecting direction of the third main connecting plate and the third auxiliary plate is collinear with the X-axis direction.

5. A strain piezoelectric composite rotor balance as claimed in claim 4, characterized in that: The floating frame or the main connecting plate is provided with a first connecting hole connected to the force-sensitive unit, and the fixed frame or the auxiliary connecting plate is provided with a second connecting hole connected to the force-sensitive unit.

6. A strain piezoelectric composite rotor balance as claimed in claim 5, characterized in that: The slide trough body specifically includes a first side plate, a second side plate, a third side plate, a main side plate and a support plate; the first side plate, the second side plate, the third side plate and the main side plate are connected end to end to form a cavity structure with openings at both ends, the main side plate and the second side plate are symmetrically arranged, the first side plate and the third side plate are symmetrically arranged, the support plate is arranged at one end of the cavity structure, the main side plate protrudes from the first side plate, the second side plate and the third side plate, the thickness of the support plate is gradually increased along the direction from the main side plate to the second side plate, so that the slide trough cavity forms a wedge-shaped cavity, and a slide trough hole for the first screw to pass through is arranged in the center of the support plate.

7. A strain piezoelectric composite rotor balance according to claim 6, characterized in that: The wedge block includes a wedge block slope and a wedge block vertical surface; the slope angle of the wedge block slope and the slope angle of the internal slope of the support plate are within the equivalent friction angle, and the wedge block slope and the internal slope of the support plate are in contact, the wedge block vertical surface is in contact with the inner side walls of the first side plate and the third side plate, and a wedge block hole for the first screw to pass through is also provided on the wedge block slope; the size of the wedge block hole is adapted to the size of the first screw, and the first screw is arranged to pass through the wedge block hole and the slide slot hole.

8. A strain piezoelectric composite rotor balance according to any one of claims 1 to 7, characterized in that: The first screw includes a cylindrical surface and a threaded surface; the cylindrical surface forms a small clearance fit with the wedge block hole, and the threaded surface is arranged at the bottom of the cylindrical surface; the decoupling connecting rod includes an external thread section, a contraction section and an internal thread section; the external thread section and the internal thread section are respectively arranged on both sides of the contraction section, and the central axes of the external thread section, the contraction section and the internal thread section are arranged collinearly, and the diameter of the contraction section is not greater than the diameter of the external thread section or the internal thread section.

9. A strain piezoelectric composite rotor balance according to any one of claims 2 to 7, characterized in that: The compound rotor balance measures the six-component load of the rotor. The corresponding relationship between the six-component load and the output signal of each strain force sensor is: The corresponding relationship between the 6-component load and the output signal of each piezoelectric force sensor is: Where: Y, X, Mz, Z, My, Mx – balance weight; Subscript "SG" - strain gauge force sensor signal; Subscript "PZ" - piezoelectric force sensor signal; ——the force sensor of the i-th group of force-sensitive units; According to the above formula, the static load of the rotor and the Nth-order high-frequency harmonic load of the rotor are obtained.

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