An adaptive variable pitch blade and propeller

Abstract

The application relates to a self-adaptive variable-pitch blade, which comprises a skin and a spar with anisotropy, the skin is wrapped outside the spar to form the blade, the thickness direction of the spar is arranged along the vertical direction, the width direction of the spar is arranged along the horizontal direction, the thickness of the spar near the blade root end of the blade is larger than the width, due to the anisotropy of the spar, when the rotating speed of the blade changes, the bending moment force received by the spar also changes, under the action of the bending-torsion coupling effect, the spar can convert the received bending moment force into torsion force, and then promotes the change of the pitch of the blade, realizes the synchronous change of the pitch and the rotating speed of the blade, and the influence trends of the pitch and the rotating speed on the flight state are the same, and then the rapid adjustment of the flight state of the aircraft is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aerospace technology, and particularly relates to a self-adaptive variable-pitch propeller blade and a propeller. BACKGROUND

[0002] Most of the existing electric flight units of aircraft adopt a fixed-pitch aviation propeller structure. Such aircraft can only adjust the flight state (including but not limited to flight height and flight attitude) of the aircraft by changing the rotation speed of the propeller blade. For example, when the flight height of the aircraft needs to be raised or lowered, the rotation speed of the propeller blade can only be raised or lowered to achieve the purpose. However, in order to ensure the stability of the aircraft during flight, the rotation speed of the propeller blade should be changed as little as possible during flight. Therefore, the above adjustment method has the problem of slow response speed, and cannot quickly adjust the flight state of the aircraft.

[0003] Therefore, there is an urgent need for a self-adaptive variable-pitch propeller blade and propeller that can quickly adjust the flight state of the aircraft. SUMMARY

[0004] To solve the above problems, the present application provides a self-adaptive variable-pitch propeller blade, which has an anisotropic spar that can produce torsional deformation when subjected to bending moment, so that the wind angle of the propeller blade can change with the change of the rotation speed, thereby improving the response speed when the flight state is changed.

[0005] To achieve the above purpose, the present application provides the following solutions:

[0006] A self-adaptive variable-pitch propeller blade comprises:

[0007] a skin and an anisotropic spar, the skin is wrapped outside the spar to form a propeller blade, the thickness direction of the spar is arranged along the vertical direction, the width direction of the spar is arranged along the horizontal direction, and the thickness of the spar near the root end of the propeller blade is greater than the width.

[0008] Preferably, the thickness of the spar gradually decreases along the extension direction of the spar.

[0009] Preferably, the self-adaptive variable-pitch propeller blade further comprises an upper surface spar and a lower surface spar, the upper surface spar and the lower surface spar are both arranged in an arc shape, the convex side of the upper surface spar is connected with the skin, the concave side of the upper surface spar is connected with one side of the thickness direction of the spar, the convex side of the lower surface spar is connected with the skin, and the concave side of the lower surface spar is connected with the other side of the thickness direction of the spar.

[0010] Preferably, the geometric center of the spar coincides with the quarter chord line of the propeller blade.

[0011] Preferably, the spar is made of carbon fiber material.

[0012] Preferably, the skin is filled with foam material between the skin and the spar.

[0013] Preferably, the skin is made of three layers of symmetrical carbon fiber layup.

[0014] Also disclosed is a propeller applying the adaptive variable pitch blade, comprising a transmission shaft and a hub, the transmission shaft is connected with a power output device, the input end of the hub is connected with the transmission shaft, the output end of the hub is connected with the blade, and the hub is a variable pitch type hub.

[0015] Preferably, it further comprises a first connecting piece, one end of the first connecting piece is connected with the hub, the other end of the first connecting piece is connected with the blade, and the first connecting piece is made of flexible composite material to rotate with the blade when the pitch of the blade changes.

[0016] Preferably, it further comprises a second connecting piece, the second connecting piece comprises a shaft sleeve and a variable pitch spindle, the sidewall of the variable pitch spindle is provided with a toothed protrusion, the inner wall of the shaft sleeve is provided with a clamping groove for accommodating the toothed protrusion, and a rotation space is arranged between the toothed protrusion and the clamping groove in the rotation direction of the variable pitch spindle, the shaft sleeve is connected with the hub, and the variable pitch spindle is connected with the blade.

[0017] The present application has the following technical effects relative to the prior art:

[0018] In the adaptive variable pitch blade disclosed by the present application, the spar has anisotropy, and when the rotation speed of the blade changes, the bending moment force received by the spar also changes, under the action of the bending-torsion coupling effect, the spar can convert the bending moment force received into torsional force, the torsional force takes the geometric center of the extension direction of the spar as the torsional center, makes the spar produce torsional deformation and drives the skin to deflect, and then can promote the pitch of the blade to change, realizes the synchronous change of the pitch and the rotation speed of the blade, specifically, when the rotation speed of the blade increases, the pitch synchronously increases, when the rotation speed of the blade decreases, the pitch synchronously decreases, the influence trend of the pitch and the rotation speed on the flight state is the same, and then the rapid adjustment of the flight state of the aircraft is realized. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] ATTACHMENT Figure 1This is a schematic diagram of one embodiment of the present invention;

[0021] Appendix Figure 2 This is a schematic diagram of a propeller in one embodiment of the present invention;

[0022] Appendix Figure 3 This is a schematic diagram illustrating the fit between the wing spars and the skin in one embodiment of the present invention;

[0023] Appendix Figure 4 This is a schematic diagram of the deformation of the wing spars in one embodiment of the present invention;

[0024] Appendix Figure 5 This is a schematic diagram of a wing beam in one embodiment of the present invention;

[0025] Appendix Figure 6 This is a schematic diagram of a wing spar according to another embodiment of the present invention;

[0026] Appendix Figure 7 This is a schematic diagram of the second connector in one embodiment of the present invention;

[0027] Appendix Figure 8 This is a schematic diagram illustrating the change of propeller pitch over time in one embodiment of the present invention;

[0028] Appendix Figure 9 This is a schematic diagram illustrating the change of tensile force over time in one embodiment of the present invention;

[0029] Appendix Figure 10 This is a schematic diagram showing the change of blade rotation speed over time in one embodiment of the present invention.

[0030] Among them, 1. Skin; 2. Wing spars; 3. Blades; 4. Upper wing spars; 5. Lower wing spars; 6. Drive shaft; 7. Hub; 8. First connecting piece; 9. Bushing; 10. Pitch control shaft; 11. Toothed protrusion; 12. Slot. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The purpose of this invention is to provide an adaptive variable pitch blade, which uses an anisotropic spar to allow the blade pitch to change with the rotational speed, thereby improving the response speed of the aircraft when it needs to change its flight state.

[0033] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0034] Reference Figures 1-7 The adaptive variable-pitch blade disclosed in the embodiments of the present application comprises a skin 1 and a spar 2, the spar 2 has anisotropy, the skin 1 is wrapped outside the spar 2 to form a blade 3, the thickness direction of the spar 2 is arranged along the vertical direction, the width direction of the spar 2 is arranged along the horizontal direction, and the thickness of the spar 2 is greater than the width of the spar 2 at the end close to the blade root of the blade 3; when the rotating speed of the blade 3 changes, the bending moment force received by the spar 2 also changes, under the bending-torsion coupling effect, the spar 2 can convert the received bending moment force into a torsional force with the geometric center of the extension direction of the spar 2 as the torsion center, the torsional force can drive the skin 1 to produce a corresponding deflection, so that the pitch of the blade 3 can change synchronously, specifically, when the rotating speed of the blade 3 increases, the pitch of the blade 3 increases, and when the rotating speed of the blade 3 decreases, the pitch of the blade 3 decreases; the increase of the pitch of the blade 3 also increases the inlet angle of the blade 3, which means that the contact between the blade 3 and the air is more effective, and more air can be pushed in a unit of time, so as to generate greater lift, that is, the influence trend of the pitch and the rotating speed on the flight state is the same, the increase of the rotating speed and the pitch are both beneficial to the increase of the lift provided by the blade 3, and the decrease of the rotating speed and the pitch are both beneficial to the decrease of the lift provided by the blade 3, which greatly improves the response speed of the aircraft applying the blade 3 when the flight state needs to be changed, so that the flight state of the aircraft can be quickly adjusted.

[0035] Those skilled in the art can understand that, under the premise that the blade 3 can provide flight force, the shape of the blade 3 in the present application can be any one of the shapes of the blades known in the prior art, which is not specifically limited here.

[0036] Preferably, the spar is made of composite material.

[0037] More preferably, the spar is made of material with anisotropy.

[0038] As a preferred embodiment, based on the rotor aerodynamics, the thickness of the spar 2 gradually decreases along the extension direction of the spar 2, that is, the airfoil of the blade tip adopts a thin airfoil, which can avoid the airflow separation in the blade tip region as much as possible.

[0039] As a preferred embodiment, the upper wing surface beam 4 and the lower wing surface beam 5 are arranged in an arc shape, the convex side of the upper wing surface beam 4 is connected with the skin 1, the concave side of the upper wing surface beam 4 is connected with one side of the thickness direction of the wing spar 2, the convex side of the lower wing surface beam 5 is connected with the skin 1, and the concave side of the lower wing surface beam 5 is connected with the other side of the thickness direction of the wing spar 2; the arrangement of the upper wing surface beam 4 and the lower wing surface beam 5 increases the connecting area between the wing spar 2 and the skin 1, so that the surface of the blade 3 can bear greater load, and meanwhile, the increase of the connecting area makes the skin 1 more easily deformed by following the torsion of the wing spar 2, thereby amplifying the effect of the torsion deformation of the wing spar 2.

[0040] Preferably, the geometric center of the wing spar 2 coincides with the quarter chord line of the blade 3; based on the aerodynamics of the rotor, the coincidence of the quarter chord line and the geometric center of the airfoil can ensure higher pitch moment stability of the blade during rotation.

[0041] As a preferred embodiment, the wing spar 2 is made of high-strength carbon fiber material; further, the skin 1 is also made of carbon fiber material.

[0042] Preferably, the wing spar 2 is made of glass fiber material.

[0043] Further, the skin 1 and the wing spar 2 are filled with foam material; specifically, the wing spar 2, the upper wing surface beam 4 and the lower wing surface beam 5 are connected with each other to form a basic frame of the blade 3, the skin 1 is wrapped outside the basic frame, and the gap between the skin 1 and the basic frame is filled with foam material; further, the skin 1 and the wing spar 2 are also filled with counterweights to meet the requirements of stiffness and strength.

[0044] As a preferred embodiment, the skin 1 is made of three-layer symmetric carbon fiber layup; preferably, the layup direction is ±45° direction.

[0045] The application further discloses a propeller applying the self-adaptive variable pitch blade, the propeller comprising a transmission shaft 6 and a hub 7, the transmission shaft 6 being connected with a power output device, the input end of the hub 7 being connected with the transmission shaft 6, and the output end of the hub 7 being connected with the blade 3; the hub 7 is a variable pitch type hub, the pitch can be pre-adjusted before the propeller rotates through the variable pitch type hub 7 to adapt to different flight modes; the power provided by the power output device is transmitted to the blade 3 through the transmission shaft 6 and the hub 7 to drive the whole propeller to work.

[0046] When the flight height of the aircraft needs to be increased, the output speed and output torque of the power output device are increased and transmitted to the hub 7 and the blades 3 through the transmission shaft 6. At this time, the torsion value of the spar 2 increases, and the torsion amount of the spar 2 increases under the bending-torsion coupling effect, so that the pitch of the blades 3 increases synchronously. Under the joint action of the speed and the pitch, the lift provided by the propeller will quickly increase, so that the flight height of the aircraft can be quickly increased. When the flight height of the aircraft needs to be reduced, the output speed and output torque of the power output device are reduced. At this time, the torsion value of the spar 2 decreases, and the torsion amount of the spar 2 decreases, so that the pitch of the blades 3 decreases synchronously. Under the joint action of the speed and the pitch, the lift provided by the propeller will quickly decrease, so that the flight height of the aircraft can be quickly reduced, thereby realizing the rapid response of the flight state of the aircraft.

[0047] As a preferred embodiment, the propeller further comprises a first connecting piece 8, one end of the first connecting piece 8 is connected with the hub 7, and the other end of the first connecting piece 8 is connected with the blade 3. The first connecting piece 8 is made of flexible composite material and can realize elastic deformation. When the pitch of the blade 3 changes with the torsion of the blade 3, the first connecting piece 8 can rotate with the blade 3 to enable the blade 3 to produce a larger angle of deflection, thereby widening the range of pitch change. It can be understood that the first connecting piece 8 has high strength in the centrifugal direction and can meet the centrifugal force requirement under the condition of high-speed rotation of the blade 3.

[0048] Further, a smooth transition structure is arranged between the first connecting piece 8 and the blade 3 and between the first connecting piece 8 and the hub 7 to ensure that the propeller has good aerodynamic performance when working.

[0049] Preferably, the first connecting piece 8 can be a part of the blade 3. Specifically, the first connecting piece 8 is an extension of the root of the blade 3, and the skin 1 at the corresponding position is smoothly transitioned to form a smooth transition structure, and the inside is filled with the spar 2, the counterweight and the foam material.

[0050] As a preferred embodiment, the propeller further comprises a second connecting piece, which comprises a shaft sleeve 9 and a variable-pitch main shaft 10. The variable-pitch main shaft 10 has a toothed protrusion 11 on the side wall, and the shaft sleeve 9 has a clamping groove 12 on the inner wall for accommodating the toothed protrusion 11. A rotation space is arranged between the toothed protrusion 11 and the clamping groove 12 in the rotation direction of the variable-pitch main shaft 10. The shaft sleeve 9 is connected with the hub 7, and the variable-pitch main shaft 10 is connected with the blade 3. The cooperation of the shaft sleeve 9 and the variable-pitch main shaft 10 can limit the pitch angle of the blade 3 and avoid the problem of aerodynamic divergence. When the blade rotates, the rotation space allows the variable-pitch main shaft 10 to rotate, and the variable-pitch main shaft 10 drives the spar 2 to rotate, and finally transmits the pitch torque to the blade 3, thereby realizing the pitch effect of the blade 3.

[0051] As a preferred embodiment, the correspondence between the pitch and the rotating speed is shown in the following table:

[0052]

[0053] Note: The reference working condition is that the rotating speed of the rotor is 1150 rpm rated rotating speed and the pitch is 8 deg rated pitch. Scheme 1 is the case of constant pitch and increasing rotating speed. Schemes 2-5 respectively correspond to the aerodynamic response of the rotor under the conditions of the pitch change degrees of 0.5, 1, 1.5 and 2 deg.

[0054] The adaptive changes according to the actual requirements are within the protection scope of the present application.

[0055] It should be noted that, for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. An adaptive pitch blade, characterized by, The adaptive variable-pitch blade comprises a skin (1) and a spar (2) with anisotropy, the skin (1) is wrapped outside the spar (2) to form a blade (3), the thickness direction of the spar (2) is arranged along the vertical direction, the width direction of the spar (2) is arranged along the horizontal direction, and the thickness of the spar (2) near the blade root end of the blade (3) is greater than the width. Further comprising an upper surface spar (4) and a lower surface spar (5), the upper surface spar (4) and the lower surface spar (5) are both arranged in an arc shape, the convex side of the upper surface spar (4) is connected with the skin (1), the concave side of the upper surface spar (4) is connected with one side of the thickness direction of the spar (2), the convex side of the lower surface spar (5) is connected with the skin (1), and the concave side of the lower surface spar (5) is connected with the other side of the thickness direction of the spar (2). The thickness of the spar (2) gradually decreases along the extension direction of the spar (2).

2. The self-adapting pitch blade of claim 1, wherein, The geometric center of the spar (2) coincides with the quarter chord line of the blade (3).

3. The self-adapting pitch blade of claim 1, wherein, The spar (2) is made of carbon fiber material.

4. The self-adapting pitch blade of claim 1, wherein, The skin (1) is filled with foam material between the skin (1) and the spar (2).

5. The self-adapting pitch blade of claim 1, wherein, The skin (1) is made of three-layer symmetric carbon fiber layup.

6. The self-adapting pitch blade of claim 1, wherein, The adaptive variable-pitch blade of any one of claims 1-6 comprises a transmission shaft (6) and a hub (7), the transmission shaft (6) is connected with a power output device, the input end of the hub (7) is connected with the transmission shaft (6), the output end of the hub (7) is connected with the blade (3), and the hub (7) is a variable-pitch hub (7).

7. A propeller, characterized in that Further comprising a first connecting piece (8), one end of the first connecting piece (8) is connected with the hub (7), the other end of the first connecting piece (8) is connected with the blade (3), and the first connecting piece (8) is made of flexible composite material to rotate with the blade (3) when the pitch of the blade (3) changes.

8. The propeller of claim 7, wherein, Further comprising a second connecting piece, the second connecting piece comprises a shaft sleeve (9) and a variable-pitch main shaft (10), the side wall of the variable-pitch main shaft (10) is provided with a toothed protrusion (11), the inner wall of the shaft sleeve (9) is provided with a clamping groove (12) for accommodating the toothed protrusion (11), a rotating space is arranged between the toothed protrusion (11) and the clamping groove (12) along the rotating direction of the variable-pitch main shaft (10), the shaft sleeve (9) is connected with the hub (7), and the variable-pitch main shaft (10) is connected with the blade (3).

9. The propeller of claim 7, wherein, ​

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