Wind tunnel small-amplitude forced rolling oscillation mechanism

Abstract

A wind tunnel small-amplitude forced rolling oscillation mechanism provided by the present invention comprises a rolling shaft, a rolling hinge, a combined eccentric shaft, a motor and a supporting rod, the rolling shaft is rotatably installed in the supporting rod, the free end of the rolling shaft protrudes out of the supporting rod, one end of the rolling hinge is fixedly connected with the rolling shaft, and the other end of the rolling hinge is fixedly connected with the front end of the supporting rod. The wind tunnel test model is fixedly connected with the free end of the rolling shaft through the balance, the driving end of the rolling shaft is connected with the output shaft of the motor through the combined eccentric shaft, and the combined eccentric shaft is connected with the eccentric hole of the rolling shaft in a matched mode. The rear section of the strut is fixedly connected with the wind tunnel supporting mechanism. According to the mechanism, the design that the motor drives the rolling shaft through the combined eccentric shaft is adopted, forced rolling oscillation of different frequencies and amplitudes can be achieved by adjusting the eccentric distance of the combined eccentric shaft and the working frequency of the motor, and technical support is provided for an aircraft stability derivative wind tunnel test.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft dynamic stability derivative wind tunnel testing, and in particular to a wind tunnel small-amplitude forced rolling oscillation mechanism. Background Art

[0002] In the wind tunnel test of the derivative of aircraft dynamic stability, the wind tunnel test model needs to oscillate around a specified axis, which can be in the form of free oscillation and forced oscillation. The free oscillation test method requires giving the model an initial deflection angle in the oscillation direction, waiting for the amplitude of the model to decay freely to a certain extent under the action of aerodynamic force. A single test takes a long time and has high test costs. The forced oscillation test method requires a system to drive the model to oscillate around a specified axis at a given frequency and amplitude. Most existing forced oscillation systems require replacement of parts to adjust the amplitude of the oscillation, which is not conducive to rapid change of test status. In addition, the mechanism is large in size, complex in structure and heavy, and cannot be used in some wind tunnels with limited dimensions. Summary of the invention

[0003] The purpose of the present invention is to provide a small-amplitude forced roll oscillation mechanism in a wind tunnel, so as to realize forced roll oscillations of different frequencies and amplitudes and provide technical support for the wind tunnel test of the dynamic stability derivative of an aircraft.

[0004] The present invention provides a small-amplitude forced roll oscillation mechanism for a wind tunnel, comprising a roll shaft, a roll hinge, a motor, a support rod and a combined eccentric shaft with adjustable eccentricity, wherein the roll shaft is rotatably installed inside the support rod, the free end of the roll shaft protrudes outside the support rod, one end of the roll hinge is fixedly connected to the roll shaft, the other end of the roll hinge is fixedly connected to the front end of the support rod, and a strain gauge is installed on the roll hinge; a wind tunnel test model is fixedly connected to the free end of the roll shaft through a balance, a rocker arm is provided at the driving end of the roll shaft, a sliding groove is provided on the rocker arm, one end of the combined eccentric shaft is cooperatively connected to the output shaft of the motor, and the other end is cooperatively connected to the sliding groove on the rocker arm; the rear section of the support rod is fixedly connected to a wind tunnel support mechanism.

[0005] Furthermore, the roll shaft, the motor and the combined eccentric shaft are combined to form a rocker arm mechanism, which converts the uniform rotational motion of the motor output shaft into the roll oscillation of the roll shaft.

[0006] Furthermore, the combined eccentric shaft includes a rocker arm eccentric shaft and a motor eccentric shaft, the motor eccentric shaft is mounted on the output shaft of the motor, the rocker arm eccentric shaft is mounted at one end of the motor eccentric shaft away from the motor, and the rocker arm eccentric shaft is connected to the eccentric hole on the rolling shaft.

[0007] Furthermore, the roll axis and the axis of the motor output shaft are parallel to each other, the distance between the two axes is the rocker arm length L, the eccentricity of the combined eccentric axis formed by the rocker arm eccentric axis and the motor eccentric axis is r, and when L>>r is satisfied, the roll angular motion of the roll axis satisfies ω is the angular velocity of the motor output shaft when it rotates at a constant speed, and t is the time.

[0008] Furthermore, by changing the angle between the eccentric directions of the rocker arm eccentric shaft and the motor eccentric shaft, different eccentric distances r can be formed in combination, thereby achieving different roll oscillation amplitudes of the roll axis.

[0009] Furthermore, the rolling shaft is rotatably mounted inside the support rod via a bearing.

[0010] Furthermore, a mounting seat is fixedly mounted inside the support rod at the driving end of the rolling shaft, the motor is fixedly mounted on the mounting seat, and the eccentric shaft of the motor is rotatably mounted on the mounting seat via a bearing.

[0011] Furthermore, the eccentric shaft of the motor is connected to the output shaft of the motor via a key.

[0012] Furthermore, a tensioning nut is cooperatively mounted on the rolling shaft, and the tensioning nut abuts against an inner ring of a bearing on the outer side of the support rod.

[0013] Furthermore, the roll hinge is arranged along the circumference of the roll axis.

[0014] The beneficial effects of the technical solution are as follows: the mechanism adopts a combined eccentric shaft with adjustable eccentricity and a sliding groove design on the roll shaft rocker arm, and can use a motor to drive the roll shaft through the combined eccentric shaft to perform forced roll oscillation. By adjusting the eccentricity of the combined eccentric shaft and the operating frequency of the motor, forced roll oscillations of different frequencies and amplitudes can be achieved, providing technical support for aircraft stability derivative wind tunnel tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is a schematic structural diagram of the small-amplitude forced rolling oscillation mechanism of the wind tunnel of the present invention.

[0017] Figure 2 It is a schematic diagram of the rocker arm mechanism of the wind tunnel small-amplitude forced rolling oscillation mechanism of the present invention.

[0018] Figure 3 It is a schematic diagram of the combined eccentric shaft of the small-amplitude forced rolling oscillation mechanism of the wind tunnel of the present invention.

[0019] Explanation of the reference numerals: 1-roll axis, 2-roll hinge, 3-support rod, 4-rocker arm eccentric shaft, 5-motor eccentric shaft, 6-mounting seat, 7-motor, 8-tensioning nut. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0022] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In the wind tunnel test of the derivative of aircraft dynamic stability, the wind tunnel test model needs to oscillate around a specified axis, in two forms: free oscillation and forced oscillation. Figure 1-Figure 3As shown, the present invention provides a small-amplitude forced roll oscillation mechanism for a wind tunnel, which adopts a rocker mechanism driven by a motor 7 and a combined eccentric shaft design. The system has high rigidity and can provide forced roll oscillations of different frequencies and amplitudes.

[0024] The entire mechanism includes a rolling shaft 1, a rolling hinge 2, a combined eccentric shaft with adjustable eccentricity, a motor 7 and a support rod 3. The rolling shaft 1 is rotatably installed inside the support rod 3 through a bearing, and the axial position of the rolling shaft 1 is fixed by a tightening nut 8 abutting against the inner ring of the bearing on the outermost side of the support rod. The tightening nut 8 is installed on the outer side of the rolling shaft 1 through threaded fitting. The free end of the rolling shaft 1 protrudes out of the support rod 3. The rolling hinge 2 is arranged along the circumference of the rolling shaft 1. One end of the rolling hinge 2 is fixedly connected to the rolling shaft 1. The other end is fixedly connected to the front end of the support rod 3, a strain gauge is attached to the roll hinge 2, and a wind tunnel test model (not shown in the figure) is fixedly connected to the free end of the roll axis 1 through a balance (not shown in the figure); a rocker arm is provided at the driving end of the roll axis 1, and a sliding groove is provided on the rocker arm along its length direction, one end of the combined eccentric shaft is connected to the output shaft of the motor, and the other end is connected to the sliding groove on the rocker arm; then the roll axis 1 is connected to the output shaft of the motor 7 through the combined eccentric shaft, so that the forced roll oscillation of the roll axis 1 can be realized.

[0025] The roll shaft 1, the motor 7 and the combined eccentric shaft form a rocker mechanism, which converts the uniform rotational motion of the output shaft of the motor 7 into the roll oscillation of the roll shaft 1. The combined eccentric shaft includes a rocker eccentric shaft 4 and an eccentric shaft 5 of the motor 7. A mounting seat 6 is fixedly installed inside the support rod 3 at the driving end of the roll shaft 1. The motor 7 is fixedly installed on the mounting seat 6. The eccentric shaft 5 of the motor 7 is rotatably installed on the mounting seat 6 through a bearing. The eccentric shaft 5 of the motor 7 is connected to the output shaft of the motor 7 through a key. The rocker eccentric shaft 4 is mounted on the end of the eccentric shaft 5 of the motor 7 away from the motor 7. The rocker eccentric shaft 4 is connected to the eccentric hole on the rocker arm of the roll shaft 1. The rocker eccentric shaft 4 acts on the rocker arm of the roll shaft 1, and finally drives the roll shaft 1 to do roll oscillation.

[0026] The tail end of the support rod 3 is fixedly connected to a wind tunnel support mechanism (not shown in the figure) to support the forced rolling oscillation mechanism in the wind tunnel test section.

[0027] During the rolling oscillation of the roll axis 1, the roll hinge 2 undergoes torsional deformation following the roll axis 1. The strain gauge on the roll hinge 2 can convert the torsional deformation into an electrical signal. The roll angular displacement of the free end of the roll axis 1 can be obtained through careful calibration. Since the wind tunnel test model is fixedly connected to the free end of the roll axis 1 through a balance, a six-component force balance is preferably used, which has a large roll stiffness and the roll deformation of the balance can be ignored. The roll angular displacement of the free end of the roll axis 1 is equal to the roll angular displacement of the model.

[0028] like Figure 2As shown, the axes of the roll axis 1 and the output shaft of the motor 7 are parallel to each other, the distance between the two axes is the rocker arm length L, the eccentric distance of the combined eccentric axis formed by the rocker arm eccentric axis 4 and the motor 7 eccentric axis 5 is r, and when L>>r is satisfied, the roll angle motion of the roll axis 1 is approximately a sinusoidal motion, and the roll angle motion of the roll axis 1 satisfies ω is the angular velocity of the output shaft of the motor 7 when it rotates at a constant speed, and t is the time.

[0029] By changing the angle between the eccentric shaft 4 of the rocker arm and the eccentric shaft 5 of the motor 7, different eccentric distances r can be formed in combination, thereby achieving different rolling oscillation amplitudes of the rolling shaft 1. Figure 3 As shown, the eccentricity of the rocker arm eccentric shaft 4 is r1, the eccentricity of the motor 7 eccentric shaft 5 is r2, and the combined eccentricity r is Wherein δ is the angle between the eccentric shaft 4 of the rocker arm and the eccentric shaft 5 of the motor 7 in the eccentric direction.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A small-amplitude forced rolling oscillation mechanism for a wind tunnel, characterized in that: It includes a roll shaft, a roll hinge, a motor, a support rod and a combined eccentric shaft with adjustable eccentricity, the roll shaft is rotatably installed inside the support rod, the free end of the roll shaft protrudes outside the support rod, one end of the roll hinge is fixedly connected to the roll shaft, the other end of the roll hinge is fixedly connected to the front end of the support rod, and a strain gauge is installed on the roll hinge; a wind tunnel test model is fixedly connected to the free end of the roll shaft through a balance, a rocker arm is provided at the driving end of the roll shaft, a sliding groove is opened on the rocker arm, one end of the combined eccentric shaft is matched with the output shaft of the motor, and the other end is matched with the sliding groove on the rocker arm; the rear section of the support rod is fixedly connected to the wind tunnel support mechanism.

2. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 1, characterized in that: The roll shaft, the motor and the combined eccentric shaft form a rocker mechanism, which converts the uniform rotational motion of the motor output shaft into the roll oscillation of the roll shaft.

3. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 2, characterized in that: The combined eccentric shaft includes a rocker arm eccentric shaft and a motor eccentric shaft. The motor eccentric shaft is mounted on the output shaft of the motor, the rocker arm eccentric shaft is mounted on the end of the motor eccentric shaft away from the motor, and the rocker arm eccentric shaft is connected with the eccentric hole on the rolling shaft.

4. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 3, characterized in that: The axis of the roll axis and the axis of the motor output shaft are parallel to each other, the distance between the two axes is the rocker arm length L, the eccentric distance of the combined eccentric axis formed by the rocker arm eccentric axis and the motor eccentric axis is r, and when L>>r is satisfied, the roll angular motion of the roll axis satisfies ω is the angular velocity of the motor output shaft when it rotates at a constant speed, and t is the time.

5. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 4, characterized in that: By changing the angle between the eccentric directions of the rocker arm eccentric shaft and the motor eccentric shaft, different eccentric distances r can be formed in combination, thereby achieving different rolling oscillation amplitudes of the rolling axis.

6. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 1, characterized in that: The rolling shaft is rotatably mounted inside the support rod via a plurality of bearings.

7. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 3, characterized in that: A mounting seat is fixedly mounted inside the support rod at the driving end of the rolling shaft, the motor is fixedly mounted on the mounting seat, and the eccentric shaft of the motor is rotatably mounted on the mounting seat via a bearing.

8. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 7, characterized in that: The motor eccentric shaft is connected to the output shaft of the motor via a key.

9. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 6, characterized in that: A tensioning nut is mounted on the rolling shaft, and the tensioning nut abuts against the inner ring of the bearing on the outer side of the support rod.

10. The wind tunnel small-amplitude forced rolling oscillation mechanism according to claim 1, characterized in that: The roll hinge is arranged along the circumference of the roll axis.

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