A dual-axis mechanism for wind tunnel testing

Abstract

The present invention belongs to the technical field of wind tunnel testing, and discloses a dual-rotating-axis mechanism for wind tunnel testing. A Z-shaped connecting support plate is installed above the middle section of the front axle of the dual-rotating-axis mechanism, and the rear end is connected to the tail cover; the top end of the connecting support plate is connected to the rear axle, and the rear axle is inserted into the middle bracket; the fairing plate is installed on the transition surface between the connecting support plate and the rear axle; the front axle and the rear axle form a dual-rotating axis, and the central axis of the front axle and the central axis of the rear axle intersect at the center of rotation of the model. When the middle bracket moves, the intersection angle remains fixed, and the intersection angle value is the maximum sideslip angle of the model. The dual-rotating-axis mechanism for wind tunnel testing of the present invention has a small structural size, large output torque, and high positioning accuracy. It can continuously, automatically, and accurately change the attitude of the aircraft model, and has practical engineering value.

Description

Technical Field

[0001] The invention belongs to the technical field of wind tunnel testing, and in particular relates to a double-rotating-axis mechanism for wind tunnel testing. Background Art

[0002] Wind tunnel testing is a crucial tool for aircraft aerodynamic research. As demands for aircraft maneuverability grow, the rolling moment generated by aircraft models during wind tunnel testing continues to increase. During supersonic testing, during the startup and shutdown of the supersonic wind tunnel, aircraft models experience impact loads far exceeding those experienced during a stable flow field. Therefore, the support structure must account for these impact loads. Furthermore, to minimize the interference of the support structure with the flow field, a support structure as small as possible must be used to accommodate aerodynamic loads under varying conditions.

[0003] In wind tunnel testing, dual-axis mechanisms are widely used as support mechanisms to simulate the aerodynamic characteristics of aircraft at different attitudes. Their transmission performance not only directly affects the accuracy of test results but also determines the upper limit of wind tunnel dynamic testing capabilities. Currently, some dual-axis mechanisms employ complex mechanical structures and large drive units, resulting in large overall dimensions and difficulty in integration into smaller test environments. This not only limits the flexibility of aircraft model layout within the wind tunnel but also increases testing costs. Other dual-axis mechanisms rely on traditional worm gear transmissions. While these mechanisms enable precise attitude adjustment of aircraft models and maintain accurate position during wind tunnel testing through structural self-locking, they are limited by space constraints and manual drive, resulting in low testing efficiency. Some dual-axis mechanisms employ harmonic reducers, enabling continuous attitude adjustment of aircraft models. However, due to the relatively low output torque of harmonic transmissions, the applicable aerodynamic load range is limited.

[0004] Currently, there is an urgent need to develop a dual-axis mechanism for wind tunnel testing. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a dual-rotating-axis mechanism for wind tunnel testing, so as to overcome the defects of the prior art.

[0006] The dual-rotating-shaft mechanism for wind tunnel testing of the present invention comprises a front shaft, a tail cover, a connecting support plate, a fairing plate, a rear shaft and a middle bracket;

[0007] A Z-shaped connecting support plate is installed above the middle section of the front axle, and the rear end is connected to the tail cover; the top end of the connecting support plate is connected to the rear axle, and the rear axle is inserted into the middle bracket; the fairing plate is installed on the transition surface between the connecting support plate and the rear axle;

[0008] The front axle and the rear axle form a double rotating axis. The central axis of the front axle and the central axis of the rear axle intersect at the center of rotation of the model. The intersection angle remains fixed when the middle bracket moves, and the intersection angle value is the maximum sideslip angle of the model.

[0009] Furthermore, the front axle includes a front drive shaft assembly, a front axle adapter shaft, a front axle reducer and a front axle drive motor connected in sequence;

[0010] The front axle drive shaft of the front drive shaft assembly serves as the main shaft. A front axle retaining ring and a front axle flange are installed at the front end of the front axle drive shaft, from the inside out. The front axle flange is secured to the connecting support plate with screws evenly distributed along the circumference. A double-row full complement cylindrical roller bearing I, an angular contact ball bearing I, a front axle oil retaining ring, a front axle bushing, an O-ring, an angular contact ball bearing II, a double-row full complement cylindrical roller bearing II, and a front axle locking nut are installed in the middle section of the front axle drive shaft. The front axle connecting flange is secured to the front axle locking nut with screws evenly distributed along the circumference.

[0011] The front end of the front axle adapter shaft is connected to the front axle connecting flange, and the rear end of the front axle adapter shaft is connected to the front axle reducer, the front axle motor flange and the front axle drive motor in sequence.

[0012] Furthermore, the wind tunnel control system of the dual-rotating shaft mechanism is provided with electrical limit and software limit; the initial zero position of the front axle drive shaft is provided with a detachable safety limit block, which is inserted into the stop groove of the front axle drive shaft and fixed on the connecting support plate.

[0013] Furthermore, the rear axle includes a rear drive shaft assembly, a rear axle adapter shaft, a rear axle reducer and a rear axle drive motor connected in sequence;

[0014] The rear axle drive shaft of the rear drive shaft assembly is the main shaft; at the front end of the rear axle drive shaft, the rear axle retaining ring and the rear axle flange are installed in sequence from the inside to the outside; in the middle section of the rear axle drive shaft, close to the rear axle retaining ring, from front to back, double-row cylindrical roller bearings, rear axle oil retaining rings, rear axle locking nut I, high-pressure locking expansion sleeves, rear shaft bushings, four-point contact ball bearings, single-row full-complement cylindrical roller bearings, rear axle locking nut II and rear axle connecting flanges are installed; the rear axle sleeve is installed on the double-row cylindrical roller bearings, rear axle oil retaining rings, rear axle locking nut I and high-pressure locking expansion sleeves. Ⅰ; the rear end face of the rear axle flange is connected to the front end face of the rear axle sleeve Ⅰ, and the contact surface is fixed to the middle bracket by screws evenly distributed along the circumference; the rear axle sleeve Ⅱ is mounted on the rear axle bushing; the rear end face of the rear axle sleeve Ⅰ is connected to the front end face of the rear axle sleeve Ⅱ, and the contact surface is connected by screws evenly distributed along the circumference; at the rear end of the rear axle drive shaft, the rear axle adapter shaft, NGW reducer, RV reducer, rear axle motor flange, rear axle drive motor and cover plate are connected in sequence; the cover plate is fixed to the middle bracket by screws evenly distributed along the circumference.

[0015] Furthermore, the front axle drive shaft and the rear axle drive shaft are both hollow shafts made of 40CrNiMoA forgings, and the central cavity is used for testing cable routing.

[0016] Furthermore, the front axle reducer of the front axle adopts cycloid pinwheel RV transmission; the NGW reducer of the rear axle adopts NGW planetary gear transmission, and the RV reducer adopts cycloid pinwheel RV transmission, and the NGW planetary gear transmission and the cycloid pinwheel RV transmission are connected in series.

[0017] Furthermore, the middle bracket and the connecting support plate are engraved with zero position scale lines, and scale lines are marked on the outer circles of the front axle flange and the rear axle flange as a measurement reference.

[0018] Furthermore, the windward surfaces of the middle bracket and the connecting support plate are both provided with sharp wedges and circular chamfers.

[0019] Furthermore, O-rings are provided between the front axle retaining ring and the front axle flange, the front axle oil retaining ring and the connecting support plate, the front axle connecting flange and the connecting support plate, the rear axle retaining ring and the rear axle flange, the rear axle drive shaft and the rear axle sleeve II, and the rear axle connecting flange and the middle bracket.

[0020] The dual-rotating-axis mechanism for wind tunnel testing of the present invention has the following characteristics:

[0021] a. The blockage rate of the dual-rotating shaft mechanism within the test section does not exceed 1.5%, and the blockage rate of the dual-rotating shaft mechanism within the bracket section does not exceed 5.5%. All components exposed to the airflow have undergone smooth transition processing, and rectifying structures such as sharp wedges and arc chamfers are set on the windward side to effectively reduce the impact of adverse flow step difference, reduce interference with the flow field, and improve the accuracy of test data.

[0022] b. The rear axle's RV reducer uses a cycloidal pinion RV drive, while the NGW reducer uses an NGW planetary gear drive. The NGW planetary gear drive and the cycloidal pinion RV drive are connected in series. The rear axle drive motor drives the RV sun gear, which is then transmitted through the planetary gears and planetary carrier to the cycloidal pinion RV, and then to the output flange of the cycloidal pinion RV. The output flange is connected to the NGW sun gear via a spline, driving the NGW planetary gears and internal gear system. Ultimately, the planetary carrier achieves low-speed, high-torque output. This meets the requirements of small size and high precision, and can also achieve continuous and automatic changes for the entire dual-axis mechanism through a wind tunnel control system.

[0023] c. The front and rear axle extensions intersect at the model's rotation center, forming a constant intersection angle. This angle represents the model's maximum sideslip angle, ensuring precise control of the model's attitude. The deviation from the actual measured sideslip angle is less than 0.05°, meeting the wind tunnel test's requirement for accurate model attitude adjustment.

[0024] d. A multiple limit protection mechanism is introduced, including mechanical limit, electrical limit and software limit to provide three-level protection. The initial zero position is set with a detachable safety limit block. After the safety limit block is removed, the wind tunnel control system adopts electrical limit and software limit to ensure that the mechanism can remain stable in any operating state, preventing over-limit movement and potential collision risks.

[0025] The dual-rotating-axis mechanism for wind tunnel testing of the present invention has small structural dimensions, large output torque, and high positioning accuracy, and can continuously, automatically, and accurately change the attitude of an aircraft model, thus having practical engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of the dual-shaft mechanism for wind tunnel testing of the present invention;

[0027] Figure 2 This is a cross-sectional view of the assembly of the front shaft, tail cover and connecting support plate in the dual-shaft mechanism for wind tunnel testing of the present invention;

[0028] Figure 3 This is an assembly cross-sectional view of the rear axle and the middle bracket in the dual-rotating-axle mechanism for wind tunnel testing of the present invention.

[0029] In the figure, 1. Front axle; 2. Tail cover; 3. Connecting support plate; 4. Fairing plate; 5. Rear axle; 6. Center bracket; 7. Front axle drive shaft; 8. Front axle retaining ring; 9. Front axle flange; 10. Double-row full complement cylindrical roller bearing I; 11. Angular contact ball bearing I; 12. Front axle oil retaining ring; 13. Front axle bushing; 14. O-ring; 15. Angular contact ball bearing II; 16. Double-row full complement cylindrical roller bearing II; 17. Front axle locking nut; 18. Front axle connecting flange; 19. Front axle adapter shaft; 20. Front axle motor flange; 21. Front axle drive motor; 22. Rear axle drive shaft; 23. Rear axle retaining ring; 24. Rear axle flange; 25. Double-row cylindrical roller bearing; 26. Rear axle oil retaining ring; 27. Rear axle locking nut I; 28. High-pressure locking sleeve; 29. ​​Rear axle sleeve I; 30. Rear axle sleeve II; 31. Rear axle bushing; 32. Four-point contact ball bearing; 33. Single-row full-complement cylindrical roller bearing; 34. Rear axle locking nut II; 35. Rear axle connecting flange; 36. Rear axle adapter shaft; 37. NGW reducer; 38. RV reducer; 39. Rear axle motor flange; 40. Rear axle drive motor; 41. Cover plate. DETAILED DESCRIPTION

[0030] In order to more clearly and comprehensively explain the technical solutions and advantages involved in the embodiments of the present invention, the exemplary embodiments of the present invention will be discussed in depth below with reference to specific diagrams. It should be noted that the embodiments herein only constitute a part of the examples of the present invention, not all of them. Based on the embodiments provided herein, other implementation schemes that can be thought of by those skilled in the art without adding creative work should be deemed to be within the scope of protection of the present invention. In addition, in the case where the technical features do not conflict with each other, the various technical features mentioned in the present invention can be used in combination with each other.

[0031] The dual-rotating shaft mechanism for wind tunnel testing of the present invention is as follows: Figure 1 As shown, it includes a front axle 1, a tail cover 2, a connecting support plate 3, a fairing plate 4, a rear axle 5 and a middle bracket 6;

[0032] A Z-shaped connecting support plate 3 is installed above the middle section of the front axle 1, and the rear end is connected to the tail cover 2; the top end of the connecting support plate 3 is connected to the rear axle 5, and the rear axle 5 is inserted into the middle bracket 6; the fairing plate 4 is installed on the transition surface between the connecting support plate 3 and the rear axle 5;

[0033] The front axle 1 and the rear axle 5 form a double rotating shaft. The central axis of the front axle 1 and the central axis of the rear axle 5 intersect at the center of rotation of the model. The intersection angle remains fixed when the middle bracket 6 moves, and the intersection angle value is the maximum sideslip angle of the model.

[0034] Further, if Figure 2 As shown, the front axle 1 includes a front drive shaft assembly, a front axle adapter shaft 19, a front axle reducer and a front axle drive motor 21 connected in sequence;

[0035] The front drive shaft assembly comprises a front axle drive shaft 7 serving as the main shaft. A front axle retaining ring 8 and a front axle flange 9 are sequentially mounted on the front end of the front axle drive shaft 7, from the inside out. The front axle flange 9 is secured to the connecting support plate 3 with screws evenly distributed along the circumference. A double-row full complement cylindrical roller bearing I 10, an angular contact ball bearing I 11, a front axle oil retaining ring 12, a front axle bushing 13, an O-ring 14, an angular contact ball bearing II 15, a double-row full complement cylindrical roller bearing II 16, and a front axle locking nut 17 are sequentially mounted on the middle section of the front axle drive shaft 7. A front axle connecting flange 18 is secured to the front axle locking nut 17 with screws evenly distributed along the circumference.

[0036] The front end of the front axle adapter shaft 19 is connected to the front axle connecting flange 18 , and the rear end of the front axle adapter shaft 19 is connected to the front axle reducer, the front axle motor flange 20 and the front axle drive motor 21 in sequence.

[0037] Furthermore, the wind tunnel control system of the dual-rotating shaft mechanism is provided with electrical limit and software limit; the initial zero position of the front axle drive shaft 7 is provided with a detachable safety limit block, which is inserted into the stop groove of the front axle drive shaft 7 and fixed on the connecting support plate 3.

[0038] Furthermore, if Figure 3 As shown, the rear axle 5 includes a rear drive shaft assembly, a rear axle adapter shaft 36, a rear axle reducer and a rear axle drive motor 40 connected in sequence;

[0039] The rear axle drive shaft 22 of the rear drive shaft assembly is the main shaft; at the front end of the rear axle drive shaft 22, the rear axle retaining ring 23 and the rear axle flange 24 are sequentially installed from the inside to the outside; in the middle section of the rear axle drive shaft 22, close to the rear axle retaining ring 23, from front to back, a double-row cylindrical roller bearing 25, a rear axle oil retaining ring 26, a rear axle locking nut I 27, a high-pressure locking sleeve 28, a rear axle bushing 31, a four-point contact ball bearing 32, a single-row full-complement cylindrical roller bearing 33, a rear axle locking nut II 34 and a rear axle connecting flange 35 are sequentially installed; after the double-row cylindrical roller bearing 25, the rear axle oil retaining ring 26, the rear axle locking nut I 27 and the high-pressure locking sleeve 28 are installed Shaft sleeve I 29; the rear end face of the rear axle flange 24 is connected to the front end face of the rear axle sleeve I 29, and the contact surface is fixed to the middle bracket 6 by screws evenly distributed along the circumference; the rear axle sleeve II 30 is mounted on the rear axle bushing 31; the rear end face of the rear axle sleeve I 29 is connected to the front end face of the rear axle sleeve II 30, and the contact surface is connected by screws evenly distributed along the circumference; at the rear end of the rear axle drive shaft 22, the rear axle adapter shaft 36, NGW reducer 37, RV reducer 38, rear axle motor flange 39, rear axle drive motor 40 and cover plate 41 are connected in sequence; the cover plate 41 is fixed to the middle bracket 6 by screws evenly distributed along the circumference.

[0040] Furthermore, the front axle drive shaft 7 and the rear axle drive shaft 22 are both hollow shafts made of 40CrNiMoA forgings, and the central cavity is used for testing cable routing.

[0041] Furthermore, the front axle reducer of the front axle 1 adopts a cycloidal pinwheel RV transmission; the NGW reducer 37 of the rear axle 5 adopts an NGW planetary gear transmission, and the RV reducer 38 adopts a cycloidal pinwheel RV transmission, and the NGW planetary gear transmission and the cycloidal pinwheel RV transmission are connected in series.

[0042] Furthermore, zero position scale lines are engraved on the middle bracket 6 and the connecting support plate 3, and scale lines are marked on the outer circles of the front axle flange 9 and the rear axle flange 24 as a measurement reference.

[0043] Furthermore, the windward surfaces of the middle bracket 6 and the connecting support plate 3 are both provided with sharp wedges and circular chamfers.

[0044] Furthermore, O-rings 14 are provided between the front axle retaining ring 8 and the front axle flange 9, the front axle oil retaining ring 12 and the connecting support plate 3, the front axle connecting flange 18 and the connecting support plate 3, the rear axle retaining ring 23 and the rear axle flange 24, the rear axle drive shaft 22 and the rear axle sleeve II 30, and the rear axle connecting flange 35 and the middle bracket 6.

[0045] Example: The test process of the dual-shaft mechanism for wind tunnel testing in this embodiment is as follows:

[0046] Before the test, the dual-axis mechanism was moved to a pre-set initial position. During this movement, the dual-axis mechanism's trajectory was dependent solely on the rear axle rotation angle δ and the scimitar operating angle θ. In the initial position (δ = 0, θ = 0), the closest point to the tunnel was 2300 mm from the rear axle center and 150 mm from the tunnel itself, providing a safety clearance.

[0047] When the middle bracket rotates in the positive direction (downward is positive), the distance between the dual-axis mechanism and the hole body becomes closer and closer. When the rear axle rotates, the distance between the dual-axis mechanism and the hole body becomes farther and farther. In order to avoid interference between the dual-axis mechanism and the hole body, the lift of the rear axle rotation should be greater than the drop of the middle bracket rotation, that is: 2300×(1-sin(δ))≥6000×sin(θ).

[0048] During the test, a dual-axis mechanism was placed in the flow field. The model's attitude was altered by rotating its two axes about their own axes. The model was designed for three main motions: a fixed sideslip angle β with a continuously varying angle of attack α; a fixed angle of attack α with a continuously varying sideslip angle β; and a fixed angle of attack α with a continuously varying roll angle γ. Wind tunnel test data was collected for each of these motions until all test objectives were met.

[0049] Close the wind tunnel, move the dual-axis mechanism to the preset end position, and the test ends.

Claims

1. A dual-axis mechanism for wind tunnel testing, characterized in that: The dual-shaft mechanism includes a front shaft, a tail cover, a connecting support plate, a fairing plate, a rear shaft and a middle bracket; A Z-shaped connecting support plate is installed above the middle section of the front axle, and the rear end is connected to the tail cover; the top end of the connecting support plate is connected to the rear axle, and the rear axle is inserted into the middle bracket; the fairing plate is installed on the transition surface between the connecting support plate and the rear axle; The front and rear axles form a double rotating shaft. The central axis of the front and rear axles intersect at the center of rotation of the model. The intersection angle remains fixed when the middle bracket moves. The intersection angle value is the maximum sideslip angle of the model. The front axle includes a front drive shaft assembly, a front axle adapter shaft, a front axle reducer and a front axle drive motor connected in sequence; The front axle drive shaft of the front drive shaft assembly serves as the main shaft. A front axle retaining ring and a front axle flange are installed at the front end of the front axle drive shaft, from the inside out. The front axle flange is secured to the connecting support plate with screws evenly distributed along the circumference. A double-row full complement cylindrical roller bearing I, an angular contact ball bearing I, a front axle oil retaining ring, a front axle bushing, an O-ring, an angular contact ball bearing II, a double-row full complement cylindrical roller bearing II, and a front axle locking nut are installed in the middle section of the front axle drive shaft. The front axle connecting flange is secured to the front axle locking nut with screws evenly distributed along the circumference. The front end of the front axle adapter shaft is connected to the front axle connecting flange, and the rear end of the front axle adapter shaft is connected to the front axle reducer, the front axle motor flange and the front axle drive motor in sequence; The rear axle includes a rear drive shaft assembly, a rear axle adapter shaft, a rear axle reducer and a rear axle drive motor connected in sequence; The rear axle drive shaft of the rear drive shaft assembly is the main shaft; at the front end of the rear axle drive shaft, the rear axle retaining ring and the rear axle flange are installed in sequence from the inside to the outside; in the middle section of the rear axle drive shaft, close to the rear axle retaining ring, from front to back, double-row cylindrical roller bearings, rear axle oil retaining rings, rear axle locking nut I, high-pressure locking expansion sleeves, rear shaft bushings, four-point contact ball bearings, single-row full-complement cylindrical roller bearings, rear axle locking nut II and rear axle connecting flanges are installed; the rear axle sleeve is installed on the double-row cylindrical roller bearings, rear axle oil retaining rings, rear axle locking nut I and high-pressure locking expansion sleeves. Ⅰ; the rear end face of the rear axle flange contacts the front end face of the rear axle sleeve Ⅰ, and the contact surface is fixed to the middle bracket by screws evenly distributed along the circumference; the rear axle sleeve Ⅱ is mounted on the rear axle bushing; the rear end face of the rear axle sleeve Ⅰ contacts the front end face of the rear axle sleeve Ⅱ, and the contact surface is connected by screws evenly distributed along the circumference; at the rear end of the rear axle drive shaft, the rear axle adapter shaft, NGW reducer, RV reducer, rear axle motor flange, rear axle drive motor and cover plate are connected in sequence; the cover plate is fixed to the middle bracket by screws evenly distributed along the circumference; The windward surfaces of the middle bracket and the connecting support plate are both provided with sharp wedges and circular chamfers.

2. The dual-axis mechanism for wind tunnel testing according to claim 1, characterized in that: The wind tunnel control system of the dual-rotating shaft mechanism is provided with electrical limit and software limit; the initial zero position of the front axle drive shaft is provided with a detachable safety limit block, which is stuck in the stop groove of the front axle drive shaft and fixed on the connecting support plate.

3. The dual-axis mechanism for wind tunnel testing according to claim 1, characterized in that: The front axle drive shaft and the rear axle drive shaft are both hollow shafts made of 40CrNiMoA forgings, and the central cavity is used for testing cable routing.

4. The dual-shaft mechanism for wind tunnel testing according to claim 1, characterized in that: The front axle reducer of the front axle adopts cycloid pinwheel RV transmission; the NGW reducer of the rear axle adopts NGW planetary gear transmission, and the RV reducer adopts cycloid pinwheel RV transmission, and the NGW planetary gear transmission and the cycloid pinwheel RV transmission are connected in series.

5. The dual-shaft mechanism for wind tunnel testing according to claim 1, characterized in that: The middle bracket and the connecting support plate are engraved with zero position scale lines, and scale lines are marked on the outer circles of the front axle flange and the rear axle flange as measurement references.

6. The dual-shaft mechanism for wind tunnel testing according to claim 1, characterized in that: O-rings are provided between the front axle retaining ring and the front axle flange, the front axle oil retaining ring and the connecting support plate, the front axle connecting flange and the connecting support plate, the rear axle retaining ring and the rear axle flange, the rear axle drive shaft and the rear axle sleeve II, and the rear axle connecting flange and the middle bracket.

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