A wind tunnel small amplitude forced roll oscillation mechanism

Abstract

The invention provides a wind tunnel small amplitude forced rolling oscillation mechanism, comprising a rolling shaft, a rolling hinge, a combined eccentric shaft, a motor and a support rod, the rolling shaft is rotatably installed inside the support rod, the free end of the rolling shaft protrudes out of the support rod, one end of the rolling hinge is fixedly connected with the rolling shaft, the other end of the rolling hinge is fixedly connected with the front end of the support rod, a wind tunnel test model is fixedly connected with the free end of the rolling shaft through a balance, the driving end of the rolling shaft is connected with the output shaft of the motor through the combined eccentric shaft, the combined eccentric shaft is connected with the eccentric hole of the rolling shaft in a matched mode; the rear section of the support rod is fixedly connected with a wind tunnel support mechanism. The mechanism adopts the design that the motor drives the rolling shaft through the combined eccentric shaft, the eccentricity of the combined eccentric shaft and the working frequency of the motor are adjusted, so that forced rolling oscillation of different frequencies and amplitudes can be realized, and technical support is provided for aircraft stability derivative wind tunnel test.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind tunnel test technology of aircraft dynamic stability derivatives, in particular to a wind tunnel small amplitude forced rolling oscillation mechanism. BACKGROUND

[0002] In the wind tunnel test of aircraft dynamic stability derivatives, the wind tunnel test model needs to oscillate around the specified axis, which has two forms of free oscillation and forced oscillation. The free oscillation test method needs to give the model an initial angle of deflection in the oscillation direction, and wait for the model to freely decay to a certain degree under the action of aerodynamic force. The single test takes a long time and has high test cost. The forced oscillation test method needs a set of system to drive the model to oscillate around the specified axis at a given frequency and amplitude. The existing forced oscillation system mostly needs to replace parts to adjust the oscillation amplitude, which is not conducive to quick replacement of test states. Moreover, the mechanism is large in size, complex in structure and heavy in weight, and cannot be used in some size-limited wind tunnels. SUMMARY

[0003] The purpose of the present application is to provide a wind tunnel small amplitude forced rolling oscillation mechanism, which realizes forced rolling oscillation at different frequencies and amplitudes, and provides technical support for wind tunnel test of aircraft dynamic stability derivatives.

[0004] The present application provides a wind tunnel small amplitude forced rolling oscillation mechanism, which comprises a rolling shaft, a rolling hinge, a motor, a support rod and an eccentricity-adjustable combined eccentric shaft. The rolling shaft is rotatably installed in the inside of the support rod, the free end of the rolling shaft protrudes out of the support rod, one end of the rolling hinge is fixedly connected with the rolling shaft, the other end of the rolling hinge is fixedly connected with the front end of the support rod, and a strain gauge is installed on the rolling hinge. The wind tunnel test model is fixedly connected with the free end of the rolling shaft through a balance, the driving end of the rolling shaft is provided with a rocker arm, a sliding groove is formed in the rocker arm, one end of the combined eccentric shaft is connected with the output shaft of the motor, and the other end is connected with the sliding groove of the rocker arm. The rear section of the support rod is fixedly connected with a wind tunnel support mechanism.

[0005] Further, the rolling shaft, the motor and the combined eccentric shaft form a rocker arm mechanism, which converts the uniform rotation of the motor output shaft into rolling oscillation of the rolling shaft.

[0006] Further, the combined eccentric shaft comprises a rocker arm eccentric shaft and a motor eccentric shaft. The motor eccentric shaft is fitted on the output shaft of the motor, the rocker arm eccentric shaft is fitted 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.

[0007] Further, the rolling shaft and the motor output shaft are parallel to each other, the distance between the two axes is the length L of the rocker arm, the eccentricity of the combined eccentric shaft formed by the rocker arm eccentric shaft and the motor eccentric shaft is r, and in the case of L>>r, the rolling angle movement of the rolling shaft satisfies ω is the angular velocity of the motor output shaft rotating at a constant speed, and t is time.

[0008] Further, the included angle of the eccentric direction of the rocker arm eccentric shaft and the motor eccentric shaft can be changed to form different eccentricities r, so as to realize different rolling oscillation amplitudes of the rolling shaft.

[0009] Further, the rolling shaft is rotatably installed in the inside of the support rod through a bearing.

[0010] Further, the support rod is fixedly installed with a mounting seat at the driving end of the rolling shaft, the motor is fixedly installed on the mounting seat, and the motor eccentric shaft is rotatably installed on the mounting seat through a bearing.

[0011] Further, the motor eccentric shaft is connected with the output shaft of the motor through a key.

[0012] Further, a tension nut is installed on the rolling shaft in cooperation, and the tension nut abuts against the inner ring of the bearing on the outside of the support rod.

[0013] Further, the rolling hinge is arranged along the circumference of the rolling shaft.

[0014] The beneficial effects of the technical solution are: the mechanism adopts the combined eccentric shaft with adjustable eccentricity and the design of the sliding groove opened on the rolling shaft rocker arm, can drive the rolling shaft to perform forced rolling oscillation through the combined eccentric shaft driven by the motor, and through adjusting the eccentricity of the combined eccentric shaft and the working frequency of the motor, different frequency and amplitude forced rolling oscillation can be realized, and technical support is provided for the stability derivative wind tunnel test of the aircraft. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0016] Fig. 1 It is a structural schematic view of the wind tunnel small amplitude forced rolling oscillation mechanism of the present application.

[0017] Fig. 2 It is a schematic view of the rocker arm mechanism of the wind tunnel small amplitude forced rolling oscillation mechanism of the present application.

[0018] Fig. 3 Figure 1 is a schematic view of a combined eccentric shaft of a wind tunnel small amplitude forced rolling oscillation mechanism of the present application.

[0019] Legend: 1-rolling shaft, 2-rolling hinge, 3-strut, 4-rocker eccentric shaft, 5-motor eccentric shaft, 6-mounting base, 7-motor, 8-tension nut. DETAILED DESCRIPTION

[0020] The technical solutions of the present application will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0021] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0022] In addition, the terms "first", "second" are only 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 with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, "a plurality of" means two or more, unless otherwise explicitly and specifically limited. In addition, the terms "mounting", "connecting", "connection" should be broadly understood, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0023] In the flight vehicle dynamic stability derivative wind tunnel test, the wind tunnel test model needs to oscillate around the specified shaft, which has two forms of free oscillation and forced oscillation. For example, Figs. 1-3As shown, the present application provides a wind tunnel small amplitude forced rolling oscillation mechanism which adopts a motor 7 driven rocker arm mechanism and a combined eccentric shaft design, the system stiffness is large, and can provide forced rolling oscillation of different frequencies and amplitudes.

[0024] The whole 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, and the axial position of the rolling shaft 1 is fixed by abutting against the inner ring of the outermost bearing of the support rod through a tension nut 8, the tension nut 8 is installed outside the rolling shaft 1 through thread cooperation, 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 with the rolling shaft 1, and the other end of the rolling hinge 2 is fixedly connected with the front end of the support rod 3, a strain gauge is attached to the rolling hinge 2, and a wind tunnel test model (not shown in the figure) is fixedly connected with the free end of the rolling shaft 1 through a balance (not shown in the figure); the driving end of the rolling shaft 1 is provided with a rocker arm, a sliding groove is formed in the rocker arm along the length direction of the rocker arm, one end of the combined eccentric shaft is connected with the output shaft of the motor, and the other end is connected with the sliding groove on the rocker arm; and then the rolling shaft 1 is connected with the output shaft of the motor 7 through the combined eccentric shaft, so that the forced rolling oscillation of the rolling shaft 1 can be realized.

[0025] The rolling shaft 1, the motor 7 and the combined eccentric shaft form a rocker arm mechanism, and the uniform rotation of the output shaft of the motor 7 is converted into the rolling oscillation of the rolling shaft 1. The combined eccentric shaft includes a rocker arm eccentric shaft 4 and a motor 7 eccentric shaft 5, an installation seat 6 is fixedly installed inside the support rod 3 at the driving end of the rolling shaft 1, the motor 7 is fixedly installed on the installation seat 6, the motor 7 eccentric shaft 5 is rotatably installed on the installation seat 6, and the motor 7 eccentric shaft 5 is connected with the output shaft of the motor 7 through a key. The rocker arm eccentric shaft 4 is fittedly installed at the end of the motor 7 eccentric shaft 5 away from the motor 7, and the rocker arm eccentric shaft 4 is connected with the eccentric hole on the rocker arm of the rolling shaft 1. The rocker arm eccentric shaft 4 acts on the rocker arm of the rolling shaft 1, and finally drives the rolling shaft 1 to roll and oscillate.

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

[0027] In the rolling oscillation process of the rolling shaft 1, the rolling hinge 2 follows the rolling shaft 1 to be twisted and deformed, the strain gauge on the rolling hinge 2 can convert the torsional deformation into an electrical signal, and the rolling angular displacement of the free end of the rolling shaft 1 can be obtained through careful calibration. Since the wind tunnel test model is fixedly connected with the free end of the rolling shaft 1 through a balance, preferably a six-component force balance, the rolling stiffness is large, and the rolling deformation of the balance can be ignored, so the rolling angular displacement of the free end of the rolling shaft 1 is equal to the rolling angular displacement of the model.

[0028] As shown in the figure, the present application provides a wind tunnel small amplitude forced rolling oscillation mechanism which adopts a motor 7 driven rocker arm mechanism and a combined eccentric shaft design, the system stiffness is large, and can provide forced rolling oscillation of different frequencies and amplitudes. Fig. 2As shown, the rolling shaft 1 and the motor 7 output shaft are parallel to each other, the distance between the two axes is the length L of the rocker arm, the eccentricity of the combined eccentric shaft formed by the rocker arm eccentric shaft 4 and the motor 7 eccentric shaft 5 is r, and in the case of L>>r, the rolling angle movement of the rolling shaft 1 is approximately sinusoidal, and the rolling angle movement of the rolling shaft 1 satisfies ω is the angular velocity of the motor 7 output shaft rotating at a constant speed, and t is the time.

[0029] By changing the included angle of the eccentric direction of the rocker arm eccentric shaft 4 and the motor 7 eccentric shaft 5, different eccentricities r can be combined to realize different rolling oscillation amplitudes of the rolling shaft 1. As shown, Fig. 3 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 Where δ is the included angle of the eccentric direction of the rocker arm eccentric shaft 4 and the motor 7 eccentric shaft 5.

[0030] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wind tunnel small amplitude forced roll oscillation mechanism, characterised in that, The combined eccentric shaft comprises a rolling shaft, a rolling hinge, a motor, a support rod and an eccentricity-adjustable combined eccentric shaft, the rolling shaft is rotatably installed inside the support rod, the free end of the rolling shaft protrudes out of the support rod, one end of the rolling hinge is fixedly connected with the rolling shaft, the other end of the rolling hinge is fixedly connected with the front end of the support rod, and a strain gauge is installed on the rolling hinge; the wind tunnel test model is fixedly connected with the free end of the rolling shaft through a balance, the driving end of the rolling shaft is provided with a rocker arm, the rocker arm is provided with a sliding groove, one end of the combined eccentric shaft is connected with the output shaft of the motor, and the other end is connected with the sliding groove of the rocker arm; and the rear section of the support rod is fixedly connected with a wind tunnel support mechanism.

2. The wind tunnel low amplitude forced roll oscillation mechanism according to claim 1, characterized in that, The rolling shaft, the motor and the combined eccentric shaft form a rocker arm mechanism, and the uniform rotation of the output shaft of the motor is converted into the rolling oscillation of the rolling shaft.

3. The wind tunnel low-amplitude forced roll oscillation mechanism according to claim 2, characterized in that, The combined eccentric shaft comprises a rocker arm eccentric shaft and a motor eccentric shaft, the motor eccentric shaft is installed on the output shaft of the motor in a matched mode, the rocker arm eccentric shaft is installed on the end of the motor eccentric shaft away from the motor in a matched mode, and the rocker arm eccentric shaft is connected with the eccentric hole on the rolling shaft in a matched mode.

4. The wind tunnel low amplitude forced roll oscillation mechanism according to claim 3, wherein, The rolling shaft and the axis of the motor output shaft are parallel to each other, the distance between the two axes is the length L of the rocker arm, the eccentricity of the combined eccentric shaft composed of the rocker arm eccentric shaft and the motor eccentric shaft is r, in the case of L>>r, the rolling angle motion of the rolling shaft satisfies ω is the angular velocity when the motor output shaft rotates at a constant speed, and t is time.

5. The wind tunnel small amplitude forced roll oscillation mechanism of claim 4, wherein, The included angle of the eccentric directions of the rocker arm eccentric shaft and the motor eccentric shaft is changed to form different eccentric distances r, so that different rolling oscillation amplitudes of the rolling shaft are realized.

6. The wind tunnel low amplitude forced roll oscillation mechanism according to claim 1, wherein, The rolling shaft is rotatably installed inside the support rod through a plurality of bearings.

7. The wind tunnel low amplitude forced roll oscillation mechanism according to claim 3, wherein, The driving end of the rolling shaft is fixedly installed with a mounting seat inside the support rod, the motor is fixedly installed on the mounting seat, and the motor eccentric shaft is rotatably installed on the mounting seat through a bearing.

8. The wind tunnel low-amplitude forced roll oscillation mechanism according to claim 7, characterized in that, The motor eccentric shaft is connected with the output shaft of the motor through a key.

9. The wind tunnel low-amplitude forced roll oscillation mechanism according to claim 6, characterized in that, The rolling shaft is installed with a tension nut in a matched mode, and the tension nut abuts against the inner ring of the bearing outside the support rod.

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

Images