Cycloidal propeller with fixed end plates

Abstract

The invention discloses a cycloid paddle with fixed end plates, and relates to the technical field of cycloid paddle design, the cycloid paddle comprises a cycloid paddle support, the tail end of the cycloid paddle support is provided with a plurality of cycloid paddle blades, and the two side edges of the cycloid paddle support are provided with the fixed end plates; the ratio of the chord length to the radius of the cycloid paddle blade is 0.55-0.66, the pitching amplitude of the cycloid paddle blade is 30-50 degrees, and the gap distance between the cycloid paddle blade and the fixed end plate is 0.2%-0.4% of the diameter of the cycloid paddle with the fixed end plate. The technical problems that in the prior art, the hovering efficiency is low, and the weight is large are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of cycloidal propeller design, and particularly to a fixed-endplate cycloidal propeller. Background Art

[0002] In the context of the accelerating urbanization process, electric vertical takeoff and landing (eVTOL) aircraft have gradually come into people's view. As a special propulsion device with characteristics such as vertical takeoff and landing capabilities, omnidirectional vector thrust, high maneuverability, and low noise, the cycloidal propeller can provide sufficient thrust at a relatively low rotational speed. At the same time, the omnidirectional vector thrust enables the aircraft to achieve a smooth transition from hovering to forward flight. Therefore, the cycloidal propeller has become one of the ideal choices for the eVTOL power system and has shown great potential in the low-altitude economy field. The main structural forms of existing cycloidal propellers are open or rotating endplate types, which have the disadvantages of low hovering efficiency and large weight. Summary of the Invention

[0003] The purpose of the present invention is to provide a fixed-endplate cycloidal propeller to solve at least one of the above technical problems.

[0004] In a first aspect, an embodiment of the present invention provides a fixed-endplate cycloidal propeller, including: a cycloidal propeller support, with a plurality of cycloidal propeller blades arranged at the end of the cycloidal propeller support, and fixed endplates arranged on both sides of the cycloidal propeller support; the ratio of the chord length to the radius of the cycloidal propeller blade is 0.55 - 0.66, and the pitch amplitude of the cycloidal propeller blade is 30° - 50°.

[0005] Further, an eccentric ring is also arranged on the side of the cycloidal propeller support, and a plurality of control tie rods are hinged on the eccentric ring, with the ends of the control tie rods connected to the sides of the cycloidal propeller blades; the control tie rods are used to control the pitch angle of the cycloidal propeller blades.

[0006] Further, the cycloidal propeller support includes a bearing sleeve, which is a tubular structure with a fixed shaft passing through its interior; both ends of the fixed shaft are fixedly connected to the fixed endplates.

[0007] In a second aspect, another embodiment of the present invention provides a fixed-endplate cycloidal propeller, including: two blade support plates arranged in parallel with each other, with a plurality of cycloidal propeller blades arranged between the two blade support plates, and fixed endplates arranged on the two outer sides of the two blade support plates respectively; the ratio of the chord length to the radius of the cycloidal propeller blade is 0.55 - 0.66, and the pitch amplitude of the cycloidal propeller blade is 30° - 50°.

[0008] Further, the middle positions of the two blade support plates are connected by a bearing sleeve, which is a tubular structure with a fixed shaft passing through its interior.

[0009] Further, an eccentric ring is provided on the blade support plate, and a plurality of control tie rods are hinged on the eccentric ring. The ends of the control tie rods are connected to the sides of the cycloidal propeller blade; the control tie rods are used to control the pitch angle of the cycloidal propeller blade.

[0010] Further, a groove structure is provided on the inner side of the fixed end plate, and the blade support plate is embedded in the groove structure.

[0011] Further, one of the fixed end plates on one side of the cycloidal propeller bracket is the side wall of the fuselage of the aircraft.

[0012] Further, the thickness of the fixed end plate is 2% - 6% of the diameter of the cycloidal propeller of the fixed end plate.

[0013] Further, the clearance distance between the cycloidal propeller blade and the fixed end plate is 0.2% - 0.4% of the diameter of the cycloidal propeller of the fixed end plate.

[0014] The present invention provides a fixed-end-plate cycloidal propeller. By arranging the cycloidal propeller blade in the middle of the fixed end plate, the generation of tip vortices can be effectively suppressed, and the hovering efficiency of the cycloidal propeller can be significantly improved; by optimizing the ratio of the chord length to the radius and the pitch amplitude of the cycloidal propeller blade, the numerical range with the highest hovering efficiency is obtained, further improving the hovering efficiency of the cycloidal propeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the specific embodiments or the description of the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a schematic structural diagram of a fixed-end-plate cycloidal propeller provided by an embodiment of the present invention; Figure 2 It is a schematic connection structure diagram of a cycloidal propeller bracket and a cycloidal propeller blade provided by an embodiment of the present invention; Figure 3 It is a schematic structural diagram of another fixed-end-plate cycloidal propeller provided by an embodiment of the present invention; Figure 4 It is a schematic structural diagram of a fixed end plate provided by an embodiment of the present invention; Figure 5Schematic diagram of the connection structure between the cycloidal propeller support and the blade support plate provided by an embodiment of the present invention; Figure 6 Schematic diagram of the installation of a fixed-end plate cycloidal propeller using the side wall surface of the fuselage as an end plate provided by an embodiment of the present invention; Figure 7 Schematic diagram of the hovering efficiency of a fixed-end plate cycloidal propeller corresponding to different chord-to-radius ratios and different pitch amplitudes provided by an embodiment of the present invention; Figure 8 Schematic diagram of the comparison of the hovering efficiency of a fixed-end plate cycloidal propeller and a rotating-end plate cycloidal propeller at different aspect ratios provided by an embodiment of the present invention; Figure 9 Schematic diagram of the comparison of the hovering efficiency of a fixed-end plate cycloidal propeller at different fixed-end plate thicknesses and aspect ratios provided by an embodiment of the present invention.

[0017] In the figure: 1. Cycloidal propeller support, 11. Bearing sleeve, 12. Control pull rod, 13. Fixed shaft, 14. Eccentric ring, 2. Cycloidal propeller blade, 3. Fixed end plate, 31. Groove structure, 4. Motor, 5. Blade support plate. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Figure 1 It is a schematic diagram of the structure of a fixed-end plate cycloidal propeller provided by an embodiment of the present invention. As Figure 1 shown, it includes: a cycloidal propeller support 1, a plurality of cycloidal propeller blades 2 are arranged at the end of the cycloidal propeller support 1, and fixed end plates 3 are arranged on both sides of the cycloidal propeller support 1.

[0020] Specifically, the ratio of the chord length to the radius of the cycloidal propeller blade 2 is 0.55 to 0.66, and the pitch amplitude of the cycloidal propeller blade 2 is 30° to 50°.

[0021] Figure 2 It is a schematic diagram of the connection structure between the cycloidal propeller support and the cycloidal propeller blade provided by an embodiment of the present invention. As Figure 1 and Figure 2 shown, an eccentric ring 14 is also arranged on the side of the cycloidal propeller support 1, a plurality of control pull rods 12 are hinged on the eccentric ring 14, and the ends of the control pull rods 12 are connected to the sides of the cycloidal propeller blades 2.

[0022] Specifically, the eccentric ring 14 is a hollow ring structure; the control tie rod 12 is used to control the pitch angle of the cycloid paddle blade 2.

[0023] Specifically, the eccentric ring 14 is divided into a fixed ring and a moving ring. The fixed ring is fixed on the cycloid paddle support 1 and is stationary. The moving ring is concentric with the fixed ring and can rotate. It rotates together with the cycloid paddle blade 2. The function of the eccentric ring 13 is to control the periodic pitch motion of the cycloid paddle blade 2.

[0024] Specifically, as Figure 2 shown, the cycloid paddle blade 2 is provided with a socket. The cycloid paddle blade 2 is inserted into the end of the cycloid paddle support 1 through the socket and is movably connected by a pin shaft. The cycloid paddle blade 2 can move at the end of the cycloid paddle support 1 and adjust the pitch amplitude.

[0025] Specifically, as Figure 1 and Figure 2 shown, the cycloid paddle support 1 includes a bearing sleeve 11. The bearing sleeve 11 is a tubular structure, and a fixed shaft 13 passes through the inside. Both ends of the fixed shaft 13 are fixedly connected to the fixed end plates 3 respectively.

[0026] Preferably, four cycloid paddle blades 2 are connected to the end of the cycloid paddle support 1.

[0027] Specifically, as Figure 2 shown, one end of the bearing sleeve 11 is in transmission connection with the motor 4. When the cycloid paddle works, the motor 4 rotates, driving the bearing sleeve 11 to rotate, and further driving the entire cycloid paddle support 1 and the cycloid paddle blade 2 to rotate. At the same time, the fixed end plate 3 remains stationary.

[0028] Figure 3 is a schematic structural diagram of another fixed-end-plate cycloid paddle provided according to an embodiment of the present invention. As Figure 3 shown, it includes: two blade support plates 5 arranged in parallel with each other. A plurality of cycloid paddle blades 2 are arranged between the two blade support plates 5. Fixed end plates 3 are respectively arranged on the two outer sides of the two blade support plates 5. The ratio of the chord length to the radius of the cycloid paddle blade 2 is 0.55 to 0.66, and the pitch amplitude of the cycloid paddle blade 2 is 30° to 50°.

[0029] Specifically, as Figure 3 shown, a plurality of connecting rods are arranged between the two blade support plates 5. The connecting rods pass through the cycloid paddle blades 2, so that the cycloid paddle blades 2 are movably fixed between the two blade support plates 5 through the connecting rods.

[0030] Specifically, as Figure 3 shown, the middle positions of the two blade support plates 5 are connected by a bearing sleeve 11. The bearing sleeve 11 is a tubular structure, and a fixed shaft 13 passes through the inside.

[0031] Specifically, if Figure 3 As shown, an eccentric ring 14 is also provided on the blade support plate 5, and a plurality of control rods 12 are hinged on the eccentric ring 14, and the ends of the control rods 12 are connected to the sides of the cycloid blades 2; the control rods 12 are used to control the pitch angle of the cycloid blades 2.

[0032] In the embodiment of the present invention, the blade support plate 5 is used to replace the cycloid propeller bracket 1, which can reduce the resistance during rotation.

[0033] Figure 4 is a structural diagram of a fixed end plate provided according to an embodiment of the present invention, such as Figure 4 As shown, a groove structure 31 is provided on the inner side of the fixed end plate 3 , and the blade support plate 5 is embedded in the groove structure 31 .

[0034] Figure 5 Schematic diagram of the connection structure between a cycloid propeller bracket and a blade support plate according to an embodiment of the present invention. Figure 5 As shown, the blade support plates 5 are circular, plate-like structures. Two blade support plates 5 are arranged parallel to each end of the cycloidal blade 2. One end of the bearing sleeve 11 is in transmission connection with the motor 4. When the cycloidal propeller is in operation, the motor 4 rotates, driving the bearing sleeve 11, which in turn drives the blade support plates 5 and the cycloidal blade 2 together, while keeping the fixed end plate 3 stationary.

[0035] Figure 6 Schematic diagram of the installation of a fixed end plate cycloid propeller using the side wall of the fuselage as the end plate according to an embodiment of the present invention. Figure 6 As shown, the fixed end plate 3 on one side of the cycloid propeller bracket 1 is the side wall of the aircraft fuselage. That is, using the side wall of the aircraft fuselage to replace the fixed end plate 3 on one side can reduce the weight and resistance of the cycloid propeller structure.

[0036] Preferably, the gap distance between the cycloid blade 2 and the fixed end plate 3 is 0.2% to 0.4% of the diameter of the fixed end plate cycloid blade.

[0037] Figure 7 : This is a schematic diagram of the hovering efficiency of a fixed end plate cycloid propeller at different chord radius ratios and different pitch amplitudes according to an embodiment of the present invention. Figure 7 As shown, for different pitch amplitudes, when the chord-to-radius ratio (C / R) (i.e., the ratio of chord length to radius) is less than 0.55, the hovering efficiency (Figure of Merit, FM) increases with the chord-to-radius ratio. When the chord-to-radius ratio is greater than 0.55, the hovering efficiency decreases with the increase of the chord-to-radius ratio. Therefore, in this embodiment of the present invention, the chord-to-radius ratio of the cycloidal propeller blade is selected to be in the range of 0.55 to 0.66, preferably 0.62.

[0038] Furthermore, ifFigure 7 As shown in Figure 7 , for different chord-to-radius ratios, the hover efficiency of the cycloidal propeller significantly increases in the pitch amplitude range of 30° - 50° compared to the range of 10° - 20°. Therefore, in the present invention, the pitch amplitude of the cycloidal propeller is selected to be 30° - 50°, preferably 39° - 41°, and more preferably 40°.

[0039] Figure 8 It is a schematic diagram comparing the hover efficiencies of a fixed-endplate cycloidal propeller and a rotating-endplate cycloidal propeller at different aspect ratios provided according to an embodiment of the present invention. Among them, Figure 8 the chord-to-radius ratio of the fixed-endplate cycloidal propeller in Figure 8 is 0.66, the pitch amplitude is 40°, and the thickness of the fixed endplate is 2 mm. As Figure 8 can be seen, for the fixed-endplate cycloidal propeller provided in the embodiments of the present invention, the hover efficiency corresponding to each aspect ratio is significantly higher than that of the traditional rotating-endplate cycloidal propeller. The main reason is that the fixed-endplate cycloidal propeller eliminates the additional power loss generated by the friction between the endplate and the air during the rotation of the endplate, resulting in the hover efficiency of the fixed-endplate cycloidal propeller being superior to that of the corresponding rotating-endplate cycloidal propeller.

[0040] Specifically, as Figure 8 shown, whether it is a rotating-endplate or a fixed-endplate cycloidal propeller, its hover efficiency decreases as the aspect ratio decreases. However, for the fixed-endplate cycloidal propeller provided in the embodiments of the present invention, when the aspect ratio is as low as 1.5, the hover efficiency can still reach 0.66, and the decrease in the hover efficiency as the aspect ratio decreases is significantly weakened. When the aspect ratio is 3, the fixed-endplate cycloidal propeller provided in the embodiments of the present invention has a maximum hover efficiency of 0.77.

[0041] Figure 9 It is a schematic diagram comparing the hover efficiencies of a fixed-endplate cycloidal propeller at different fixed-endplate thicknesses and aspect ratios provided according to an embodiment of the present invention. Among them, Figure 9 the chord-to-radius ratio of the fixed-endplate cycloidal propeller in Figure 9 is 0.66, and the pitch amplitude is 40°. As Figure 9 shown, for different aspect ratios (Aspect Ratio, AR), the hover efficiency of the 25-mm-thick fixed endplate is greater than that of the 2-mm-thick fixed endplate. Preferably, in the embodiments of the present invention, the thickness of the fixed endplate 3 is 2% - 6% of the diameter of the fixed-endplate cycloidal propeller, and preferably 5.56%.

[0042] The main reason is that the inflow of the propeller disk will form significant endplate vortices on the thin-walled endplate and the blade surface, resulting in the loss of the thrust of the cycloidal propeller and additional power consumption. While the endplate with a thickness can eliminate this adverse vortex, increasing the thrust generated by the blade and reducing the aerodynamic torque at the same time, thus further improving the hover efficiency of the cycloidal propeller.

[0043] As Figure 9As shown in the figure, the parameters of the fixed-end-plate cycloidal propeller provided by the embodiment of the present invention with the best hover efficiency are a fixed-end-plate cycloidal propeller with an aspect ratio of 3 and an end-plate thickness of 5.56% of the diameter of the cycloidal propeller, and its hover efficiency can reach 0.77.

[0044] From the above description, it can be seen that the embodiment of the present invention provides a fixed-end-plate cycloidal propeller. By arranging the cycloidal propeller blades in the middle of the fixed end plate, the generation of tip vortices can be effectively suppressed, and the hover efficiency of the cycloidal propeller can be significantly improved. By optimizing the ratio of the chord length to the radius of the cycloidal propeller blades and the pitch amplitude, the numerical range with the highest hover efficiency is obtained, further improving the hover efficiency of the cycloidal propeller. Moreover, the weight is reduced by more than half compared with the existing cycloidal propeller, reducing the structural gravity and resistance.

[0045] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0046] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A fixed-end plate cycloidal propeller, comprising: Cycloidal propeller support, with multiple cycloidal propeller blades arranged at the end of the cycloidal propeller support. It is characterized in that fixed end plates are arranged on both sides of the cycloidal propeller support; the ratio of the chord length to the radius of the cycloidal propeller blade is 0.55 - 0.66, and the pitch amplitude of the cycloidal propeller blade is 30° - 50°.

2. The fixed-end plate cycloidal paddle according to claim 1, characterized in that: An eccentric ring is also arranged on the side of the cycloidal propeller support, and a plurality of control tie rods are hinged on the eccentric ring. The end of the control tie rod is connected to the side of the cycloidal propeller blade; The control tie rod is used to control the pitch angle of the cycloidal propeller blade.

3. The fixed-end plate cycloidal propeller according to claim 2, characterized in that: The cycloidal propeller support includes a bearing sleeve, which is a tubular structure with a fixed shaft passing through its interior; both ends of the fixed shaft are fixedly connected to the fixed end plates respectively.

4. A fixed-end plate cycloid paddle, comprising: Two blade support plates are arranged in parallel with each other, and multiple cycloidal propeller blades are arranged between the two blade support plates. It is characterized in that fixed end plates are respectively arranged on the two outer sides of the two blade support plates; the ratio of the chord length to the radius of the cycloidal propeller blade is 0.55 - 0.66, and the pitch amplitude of the cycloidal propeller blade is 30° - 50°.

5. The fixed-end plate cycloidal propeller according to claim 4, wherein: The middle positions of the two blade support plates are connected by a bearing sleeve, which is a tubular structure with a fixed shaft passing through its interior.

6. The fixed-end plate cycloidal propeller according to claim 4, characterized in that: An eccentric ring is also arranged on the blade support plate, and a plurality of control tie rods are hinged on the eccentric ring. The end of the control tie rod is connected to the side of the cycloidal propeller blade; The control tie rod is used to control the pitch angle of the cycloidal propeller blade.

7. The fixed-end plate cycloid paddle according to claim 4, wherein: A groove structure is arranged on the inner side of the fixed end plate, and the blade support plate is embedded in the groove structure.

8. The fixed-end plate cycloid paddle according to claim 4, wherein: The fixed end plate on one side of the cycloidal propeller support is the side wall of the aircraft fuselage.

9. The fixed-end plate cycloid paddle according to any one of claims 1-8, characterized in that: The thickness of the fixed end plate is 2% - 6% of the diameter of the cycloidal propeller of the fixed end plate.

10. The fixed-end plate cycloidal paddle according to any one of claims 1-8, characterized in that: The clearance distance between the cycloidal propeller blade and the fixed end plate is 0.2% - 0.4% of the diameter of the cycloidal propeller of the fixed end plate.

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