Variable diameter blade for a variable speed helicopter rotor

Abstract

The embodiment of the present application discloses a variable diameter blade for a variable speed rotor of a helicopter, and relates to the technical field of rotorcrafts.The present application comprises: a counterweight mounted in an outer blade guide, connected with the blade through a spring, and connected with the outer blade and the counterweight through a flexible rope around a pulley mounted on a fixed crossbar of the blade, and the outer blade is sleeved in the blade in a slightly smaller size and the same shape.When the rotor speed increases, the counterweight moves outward, the outer blade moves inward relative to the blade, and the rotor radius decreases instead.Thus, a variable diameter blade with simple structure, easy use, and relatively convenient production and maintenance is designed, and the diameter can be automatically changed according to the rotor speed.The present application is suitable for the blade of a variable speed rotor.

Description

Technical Field

[0001] This invention relates to the field of rotorcraft technology, and more particularly to a variable diameter blade for a helicopter variable speed rotor. Background Technology

[0002] Helicopters have a wide range of applications in both civilian and military fields due to their unique vertical takeoff and landing, hovering, and low-altitude capabilities. However, because of their unique lift generation method, helicopters are generally not very efficient in flight. Variable-speed rotors can improve helicopter flight performance and reduce power consumption to adapt to different flight environments and flight conditions.

[0003] Research has found that smaller rotor radii are better suited for high-speed flight, while larger rotors are better suited for hovering or low-speed flight. Therefore, variable-diameter blades offer significant gain for variable-speed rotor systems. Optimizing the design of a variable-diameter blade that is simple to use, easy to manufacture, and relatively convenient to maintain has become a research topic. Summary of the Invention

[0004] The embodiments of the present invention provide a variable diameter blade for a helicopter variable speed rotor. The variable diameter blade is designed to be simple in structure, easy to use, relatively convenient to produce and maintain, and can adaptively change its diameter according to the rotor speed.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] The main body of the variable diameter blade includes a main blade (1) and an extended blade (2). The cross section of the main blade (1) and the cross section of the extended blade (2) are connected by a variable diameter connecting mechanism.

[0007] The main blade (1) is divided into upper and lower halves. At least two main blade metal crossbeams (11) are installed on the upper half of the main blade (1). A main blade connector (10) is installed at the section where the main blade metal crossbeams (11) extend out of the main blade (1).

[0008] The extended blade (2) is also divided into upper and lower halves. At least two extended blade metal beams (7) are installed in the upper half of the extended blade (2). An extended blade connector (4) is installed at the section where the extended blade metal beam (7) extends out of the extended blade (2).

[0009] The counterweight (3) is arranged on the guide rail in the extended blade (2) so that the counterweight (3) can move radially along the guide rail. The shape of the counterweight (3) is a cuboid.

[0010] The lower half of the main blade (1) and the lower half of the extended blade (2) are filled with blade foam filler (8);

[0011] The variable diameter connection mechanism includes: an elastic connector and a non-elastic connector. The elastic connector is used to connect the extended blade metal beam (7) and the main blade metal crossbeam (11). One end of the non-elastic connector is connected to a counterweight (3), and the other end of the non-elastic connector is fixed to the crossbeam of the extended blade metal beam (7) after passing over a fixed pulley (12) arranged at the crossbeam of the main blade (1). Connectors (4) are installed at the crossbeam of the extended blade (2), and connectors (10) are installed at the crossbeam of the metal beam on the opposite side of the main blade (1), and are connected to two springs (5). A metal crossbeam (11) is fixed to the two connectors (10) by screws, and a fixed pulley (12) with a support is installed in the middle.

[0012] The variable-diameter rotor blade for a helicopter variable-speed rotor provided in this invention involves installing a counterweight in a sliding guide rail of the extended blade, connected to the main blade by a flexible rope and two springs. When the blade accelerates, the counterweight moves outward under centrifugal force, causing the end of the rope connected to the counterweight to move outward, while the end of the rope connected to the extended blade moves inward. This causes the extended blade to move inward relative to the main blade, shortening its diameter. When the rotor speed becomes constant, the spring force and centrifugal force balance, and the blade diameter remains unchanged. Conversely, when the rotor speed decreases, the centrifugal force on the counterweight decreases, and the spring force exceeds the centrifugal force. The counterweight moves inward radially along the blade, while the extended blade moves outward, increasing its diameter. By utilizing the changes in centrifugal force and spring force, the blade diameter can be adaptively changed, thereby improving the rotor's efficiency and performance. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A schematic diagram of the assembly structure of the variable diameter rotor blade of a helicopter variable speed rotor system provided in an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of the cross-sectional assembly of the main blade (1) provided in an embodiment of the present invention;

[0016] Figure 3 This is a schematic diagram showing the cross-section of the main blade and the connecting parts provided in an embodiment of the present invention;

[0017] Figure 4This is a schematic diagram of the assembly of the connector (10), the metal beam (11), and the pulley (12) provided in an embodiment of the present invention;

[0018] Figure 5 This is an overall schematic diagram of the extended blade (2) provided in an embodiment of the present invention;

[0019] Figure 6 A schematic diagram of the external shape and structure of the connector (4) provided in an embodiment of the present invention;

[0020] Figure 7 A schematic diagram of the shape and structure of the counterweight (3) provided in an embodiment of the present invention;

[0021] Figure 8 A schematic diagram of the assembly connector (4) for the extended blade (2) provided in an embodiment of the present invention and its structure;

[0022] Figure 9 A schematic diagram of the overall assembly of the main blade (1), the extended blade (2) and the counterweight (3) provided in the embodiment of the present invention;

[0023] Figure 10 This is a schematic diagram of a possible main blade structure provided in an embodiment of the present invention;

[0024] The labels in the attached drawings represent: main blade - 1, extended blade - 2, counterweight - 3, extended blade connector - 4, spring - 5, non-elastic flexible rope - 6, extended blade metal beam - 7, blade foam filler - 8, skin - 9, main blade connector - 10, metal crossbeam - 11, pulley - 12. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0026] Current research has found that conventional helicopter rotors rotate at a fixed speed, and their blades are mostly of a fixed diameter, which cannot adapt to the complex and variable aerodynamic environment of helicopters. To address this issue, this embodiment provides an adaptive variable-diameter blade system suitable for variable-speed helicopter rotors, and offers a design concept. Specifically, it achieves adaptive elongation or shortening of the rotor blades within a certain radial range. While the design of variable-diameter blades and variable-speed helicopters can improve helicopter performance, it also has some negative impacts on aspects such as blade dynamics analysis, requiring more comprehensive calculations and evaluations in practical applications.

[0027] This invention provides a variable diameter blade for a helicopter variable speed rotor, such as... Figure 1 , 9 As shown, it includes:

[0028] The main body of the variable diameter blade includes a main blade (1) and an extended blade (2). The cross section of the main blade (1) and the cross section of the extended blade (2) are connected by a variable diameter connecting mechanism.

[0029] The main blade (1) is divided into upper and lower halves. At least two main blade metal crossbeams (11) are installed on the upper half of the main blade (1). A main blade connector (10) is installed at the section where the main blade metal crossbeams (11) extend out of the main blade (1).

[0030] The extended blade (2) is also divided into upper and lower halves. At least two extended blade metal beams (7) are installed in the upper half of the extended blade (2). An extended blade connector (4) is installed at the section where the extended blade metal beam (7) extends out of the extended blade (2).

[0031] The counterweight (3) is arranged on the guide rail in the extended blade (2) so that the counterweight (3) can move radially along the guide rail. The shape of the counterweight (3) is a cuboid.

[0032] The lower half of the main blade (1) and the lower half of the extended blade (2) are filled with blade foam filler (8);

[0033] The variable diameter connection mechanism includes: an elastic connector and a non-elastic connector. The elastic connector is used to connect the extended blade metal beam (7) and the main blade metal crossbeam (11). One end of the non-elastic connector is connected to a counterweight (3), and the other end of the non-elastic connector is fixed to the crossbeam of the extended blade metal beam (7) after passing around a fixed pulley (12) arranged at the cross-section of the main blade (1).

[0034] Among them, such as Figure 2-5 As shown, the elastic connector uses a spring (5), and the non-elastic connector uses a non-elastic flexible rope (6). An extended blade metal beam (7) and a main blade metal crossbeam (11) are of equal number to form a pair of beams, each pair installed on the same horizontal plane; in each pair of beams, one end of the spring (5) is connected to the main blade connector (10), and the other end is connected to the extended blade connector (4). The spring (5) is fixedly connected to the connector (10) on the main blade (1) and the connector (4) on the extended blade (2) through hooks machined at both ends of the spring (5). Connectors (4) are installed at the cross-section of the extended blade (2) metal beam, and connectors (10) are installed at the cross-section of the metal beam on the opposite side of the main blade (1), and connected to two springs (5). A metal crossbeam (11) is fixed to the two connectors (10) by screws, and a fixed pulley (12) with a support is installed in the middle.

[0035] In this embodiment, both the main blade (1) and the extended blade (2) are encased in a skin (9); lubricating oil is applied to the inner surface of the skin (9) that contacts the extended blade (2). The skin (9) is a rigid skin so that when the variable diameter blade is stationary, the weight of the extended blade (2) can be supported by the rigidity of the skin (9).

[0036] Specifically, the counterweight (3) has radially grooved openings on both sides, which can be implemented in at least three structures, including:

[0037] Firstly, a guide rail is installed on the upper part of the extended blade (2), and the guide rail is parallel to the metal beam (7) of the extended blade; the counterweight (3) is arranged on the guide rail in the extended blade (2), and the guide rail is machined with a protruding part in the radial direction. The shape of the protruding part of the guide rail matches the groove of the counterweight (3) so that the counterweight (3) can move radially in the guide rail of the metal beam (7) of the extended blade.

[0038] Secondly, the grooves are located on the upper and lower surfaces of the counterweight (3) and are radially opened. The position and shape of the grooves on the upper and lower surfaces are matched with the installation position and shape of the two extended blade metal beams (7), so that the counterweight (3) can use the extended blade metal beams (7) as guide rails for radial movement.

[0039] Optionally, when using the metal beam (7) as a guide rail, grooves matching the protrusions can be cut into the metal beam (7); when the counterweight (3) is installed on the guide rail, the protrusions machined above and below the counterweight (3) are respectively placed in the grooves cut into the guide rail. In practical applications, the machined metal beam itself also needs to provide bending and torsional strength, so it is not suitable for subtractive design. Therefore, in this embodiment, it is preferred to use a groove design for the counterweight.

[0040] Thirdly, such as Figure 8 As shown, the counterweight (3) has elongated protrusions machined radially on both sides; a guide rail is also installed on the upper half of the extended blade (2), and the guide rail is parallel to the metal beam (7) of the extended blade; the counterweight (3) is arranged on the guide rail in the extended blade (2), and the guide rail has a grooved part machined radially. The shape of the groove of the guide rail matches the elongated protrusion of the counterweight (3) so that the counterweight (3) can move radially in the guide rail of the metal beam (7) of the extended blade.

[0041] In the preferred solution, such as Figure 6 , 7As shown, a semi-circular ring is fixedly installed on the front end face of the counterweight (3), and one end of the non-elastic flexible rope (6) is connected to the semi-circular ring; the other end of the non-elastic flexible rope (6) passes around the fixed pulley (12) and is fixed to an extended blade connector (4), and the position of this extended blade connector (4) is higher than that of the counterweight (3). Among them, the connector (10) at the cross section of the main blade (1) is installed on two walls of the metal beam, and the two ends of the metal crossbeam (11) are installed on the cross section of the main blade (1) through the connector (10). The support of the fixed pulley (12) is welded to the opposite surface of the metal crossbeam (11), so that the non-elastic flexible rope (6) can pass around the pulley (12) to achieve sliding.

[0042] Optional, such as Figure 10 As shown, one end of the main blade (1) is open and extends out to a limiting flange. The front end of the extended blade (2) is nested in the main blade (1). The length of the limiting flange is longer than the maximum length of the non-elastic connector.

[0043] In practical applications, the counterweight (3) is installed in the guide rail of the metal beam (7) of the extended blade (2), and the counterweight (6) moves radially along the extended blade (2) in the guide rail. A ring is machined at the front of the counterweight (3) and fixedly connected to one end of the inelastic flexible rope (6). The overall size of the extended blade (2) is slightly smaller than that of the main blade (1), and its cross-sectional shape is the same as that of the main blade (1) and it can slide freely within the skin (9) of the main blade. Two connectors (4) are fixedly connected to the cross-section of the metal beam (7) of the extended blade (2), and are respectively fixedly connected to one end of two springs (5). Two connectors (10) are fixedly connected to the open cross-section of the metal beam of the main blade (1), and the rings at both ends of the connectors (10) are respectively fixedly connected to the other ends of the two springs (5). The connectors (10) themselves are connected to the inner wall of the metal beam. The metal beam (11) is fixedly connected to the connector (10) at both ends, and a fixed pulley (12) with a support is installed in the middle so that the inelastic flexible rope (6) can pass through and slide. The connector (4) of the metal beam (7) of the extended blade (2) is machined with a semi-circular ring at the front end so that the inelastic flexible rope (6) is fixedly connected to the extended blade (2).

[0044] like Figure 3 The counterweight (3) shown has protruding parts at its top and bottom for mounting in the metal guide rail (7) of the extended blade (2). Specifically, protruding parts are machined on both the top and bottom of the counterweight (3), and two grooves matching the protruding parts are opened in the guide rail. When the counterweight (3) is mounted on the guide rail, the protruding parts on both the top and bottom of the counterweight (3) are respectively placed in the grooves opened in the guide rail.

[0045] The specific working principle of the device provided in this embodiment can be understood as follows: During the variable speed process of the blade, as the speed increases, the centrifugal force on the counterweight (3) increases, causing it to move radially outward along the extended blade (2). The inelastic flexible rope (6) drives the extended blade (2) to move radially inward along the main blade (1) until the centrifugal force and tension on the counterweight (3) and the extended blade (2) are balanced with the elastic tension generated by the spring (5), and the blade diameter decreases. Conversely, when the speed decreases, the extended blade (2) moves radially outward within the skin of the main blade (1) until the radial force is balanced, and the blade diameter increases. Through this mechanism, the helicopter can flexibly change its speed when facing complex aerodynamic environments and flight conditions. At the same time, the blade can adaptively change its diameter according to the rotor speed, reducing power consumption and further improving the flight performance of the helicopter.

[0046] This embodiment provides a variable-diameter blade for a variable-speed rotor system. A counterweight is installed in the sliding guide rail of the extended blade and connected to the main blade by a flexible rope and two springs. When the blade accelerates, the counterweight moves outward under centrifugal force, causing the end of the rope connected to the counterweight to move outward, while the end of the rope connected to the extended blade moves inward. This causes the extended blade to move inward relative to the main blade, shortening its diameter. When the rotor speed becomes constant, the spring force and centrifugal force balance, and the blade diameter remains unchanged. Conversely, when the rotor speed decreases, the centrifugal force on the counterweight decreases, and the spring force exceeds the centrifugal force. The counterweight moves inward along the blade's radial direction, while the extended blade moves outward, increasing its diameter. By utilizing the changes in centrifugal force and spring force, the blade diameter can be adaptively changed, thereby improving the rotor's efficiency and performance.

[0047] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A variable-diameter blade for a helicopter variable-speed rotor, characterized in that, include: The main body of the variable diameter blade includes a main blade (1) and an extended blade (2). The cross section of the main blade (1) and the cross section of the extended blade (2) are connected by a variable diameter connecting mechanism. The main blade (1) is divided into upper and lower halves. At least two main blade metal crossbeams (11) are installed on the upper half of the main blade (1). A main blade connector (10) is installed at the section where the main blade metal crossbeam (11) extends out of the main blade (1). The extended blade (2) is also divided into upper and lower halves. At least two extended blade metal beams (7) are installed in the upper half of the extended blade (2). An extended blade connector (4) is installed at the section where the extended blade metal beam (7) extends out of the extended blade (2). The counterweight (3) is arranged on the guide rail in the extended blade (2) so that the counterweight (3) can move radially along the guide rail. The shape of the counterweight (3) is a cuboid. The lower half of the main blade (1) and the lower half of the extended blade (2) are filled with blade foam filler (8). The variable diameter connection mechanism includes: an elastic connector and a non-elastic connector, wherein the elastic connector is used to connect the extended blade metal beam (7) and the main blade metal crossbeam (11). One end of the non-elastic connector is connected to the counterweight (3), and the other end of the non-elastic connector is fixed to the cross section of the extended blade metal beam (7) after passing around the fixed pulley (12) arranged at the cross section of the main blade (1).

2. The variable diameter blade according to claim 1, characterized in that, The elastic connector is a spring (5), and the non-elastic connector is a non-elastic flexible thin rope (6).

3. The variable diameter blade according to claim 1 or 2, characterized in that, An outstretched blade metal beam (7) and a main blade metal crossbeam (11) are of the same number to form a pair of beams, and each pair of beams is installed on the same horizontal plane; In each pair of beams, one end of the spring (5) is connected to the main blade connector (10) and the other end is connected to the extended blade connector (4).

4. The variable diameter blade according to claim 1, characterized in that, Both the main blade (1) and the extended blade (2) are encased in the skin (9); Lubricating oil is applied to the inner surface of the skin (9) that contacts the extended blade (2); The skin (9) is a rigid skin so that when the variable diameter blade is at rest, the weight of the extended blade (2) is supported by the rigidity of the skin (9).

5. The variable diameter blade according to claim 1, characterized in that, The counterweight (3) has grooves on both sides along the radial direction.

6. The variable diameter blade according to claim 5, characterized in that, A guide rail is also installed on the upper part of the extended blade (2), and the guide rail is parallel to the metal beam (7) of the extended blade; The counterweight (3) is arranged on the guide rail in the extended blade (2). The guide rail is machined with a protruding part in the radial direction. The shape of the protruding part of the guide rail matches the groove of the counterweight (3) so that the counterweight (3) can move radially in the guide rail of the extended blade metal beam (7).

7. The variable diameter blade according to claim 5, characterized in that, The grooves are located on the upper and lower surfaces of the counterweight (3) and are radially opened. The position and shape of the grooves on the upper and lower surfaces are matched with the installation position and shape of the two extended blade metal beams (7), so that the counterweight (3) can use the extended blade metal beams (7) as guide rails for radial movement.

8. The variable diameter blade according to claim 1, characterized in that, Long strip grooves are machined radially on both sides of the counterweight (3); A guide rail is also installed on the upper part of the extended blade (2), and the guide rail is parallel to the metal beam (7) of the extended blade; The counterweight (3) is arranged on the guide rail in the extended blade (2). The guide rail is machined with a groove in the radial direction. The shape of the groove in the guide rail matches the elongated protrusion of the counterweight (3) so that the counterweight (3) can move radially in the guide rail of the extended blade metal beam (7).

9. The variable diameter blade according to claim 3, characterized in that, A semi-circular ring is fixedly installed on the front end face of the counterweight (3), and one end of the non-elastic flexible thin rope (6) is connected to the semi-circular ring; The other end of the non-elastic flexible thin rope (6) passes over the fixed pulley (12) and is fixed to an extended blade connector (4), and the position of this extended blade connector (4) is higher than the counterweight (3).

10. The variable diameter blade according to claim 1, characterized in that, One end of the main blade (1) is open and extends out to a limiting flange. The front end of the extended blade (2) is nested in the main blade (1). The length of the limiting flange is longer than the maximum length of the non-elastic connector.

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