Periodic pitch angle adjustment equipment

Abstract

The present embodiment relates to a periodic pitch angle adjustment device (200) for a rotor (110) or a propeller, a rotor (110) having such a periodic pitch angle adjustment device (200), and a rotorcraft (100) having such a rotor (110). A cyclic pitch angle adjustment device (200) may include: levers (230a, 230b) that rotate rotor blades (212a, 212b) about associated pitch adjustment axes (235a, 235b); links (240a, 240b) that mechanically connect the levers (230a, 230b) to a bearing (220) so that the links (240a, 240b) can move relative to a center point (223), the bearing (220) being attached to a center link (250), the center link (250) being movable and adapted to adjust the cyclic pitch angle of the rotor blades (112) from one pitch angle in one position to another pitch angle in another position (265).

Description

Technical Field

[0001] The present embodiment relates to rotors and propellers, and more particularly, to a periodic pitch angle adjustment device for controlling the periodic pitch angle of rotor blades of a rotor or propeller. In addition, the present embodiment relates to a rotor having such a periodic pitch angle adjustment device and a rotorcraft having such a rotor. Background Art

[0002] A rotor is typically configured to generate thrust in a predetermined direction during operation. The thrust generated by the rotor blades of the rotor can be controlled in two different ways: either by controlling the rotational speed of the rotor blades about the rotor axis, or by controlling the aerodynamic lift coefficient of the rotor blades. The aerodynamic lift coefficient is typically controlled by adjusting the base pitch angle of the rotor blades.

[0003] It is also desirable that the pitch angle regulation compensate for asymmetries in the air speed, for example during operation in a non-axial flow field, i.e. when the air flow has a component perpendicular to the rotor plane and at the same time a component transverse to the rotor plane. In a non-axial flow field, depending on the current position of the rotor blades, some rotor blades rotate against the transverse airflow, while other rotor blades rotate with the transverse airflow, which results in an imbalance in the lift of the different rotor blades. The unbalanced lift usually results in vibration stresses on the rotor blades. Controlling the pitch angle of each rotor blade individually according to its rotational position (which is sometimes also referred to as "cyclic pitch control" or "cyclic pitch actuation") can result in a uniform distribution of lift on all rotor blades.

[0004] Controlling the rotor blade pitch angle requires either active or passive control of the flexible joints in the rotor assembly. In actively controlled rotor assemblies, each associated rotor blade is articulated and individually controlled in its rotational azimuth, which typically requires complex, bulky, and cost-intensive pitch control mechanisms that require active control devices with external energy supplies to individually adjust the pitch angle of each rotor blade.

[0005] Actively controlled rotor assemblies are usually equipped with not only cyclic pitch adjustment devices but also collective pitch adjustment devices in order to be effective for lift and drag. Examples of actively controlled rotor assemblies with pitch adjustment devices are described in US 2,684,721, EP 1985536, DE 102005007129, DE 102004053001, US 3,556,674, US 3,228,629, GB 576876, GB 612688, GB 6623240, GB 8074223 and US 3,508,841.

[0006] However, cyclic and collective pitch control devices generally have a relatively large complexity and weight and require the implementation of cost-intensive, complex control mechanisms and monitoring devices. More specifically, cyclic and collective pitch control devices generally include pitch control levers that are moved by a swash plate or a ring that is axially movable around the corresponding rotor strut.

[0007] Document EP3533710B1 describes a rotor or propeller having rotor blades and a passive pitch angle adjustment device. The passive pitch angle adjustment device comprises a lever, a connecting rod and a central connecting rod. The lever is connected to the rotor blades and causes them to rotate about the corresponding pitch adjustment axis. The connecting rod is connected to the lever and mechanically connects the levers to each other via a center point located outside the rotor plane. The central connecting rod connects the center point to a base point located in the longitudinal direction of the rotor axis. The passive pitch angle adjustment device enables periodic pitch adjustment of the rotor blades.

[0008] Document US2,978,037 describes a stabilization system for simultaneously adjusting (a) the total pitch of a helicopter rotor blade, and (b) the periodic pitch variation of one or more of its blades. The stabilization system comprises a simple arrangement of an inner annular member and an outer annular member. The inner annular member can rotate about a fixed eccentric axis. The outer annular member is rotatably arranged about the inner annular member and is connected to the blades of the helicopter rotor by an articulated connecting member to change the pitch of the latter. The rotor also includes a linkage arrangement that indicates the inclination of the blade cone and automatically converts this inclination into an interdependent adjustment of the total pitch and individual pitch variations of the rotor blades at the same time. In other words, the inclination of the entire blade cone serves as an input for balancing lift, and due to the fixed position of the eccentric axis, the stabilization system only works in one direction of flight. Therefore, the stabilization system cannot compensate for the effects of crosswinds or sideways flight.

[0009] Document US3,756,743A describes a hub for a rigid rotor of a rotary wing aircraft, the hub comprising a device for varying the blade angle of attack of each blade of the rotor as each blade rotates about a path described by the trajectory of the rotor to produce non-sinusoidal cyclic pitch variations while independently allowing sinusoidal cyclic pitch control to be superimposed thereon by the medium of a spider, the device being associated with each blade root and comprising a spindle for each blade, the spindles being equidistantly mounted for rotational movement in a rotatable part of the hub and being in helical spline engagement at their inner ends with plungers, the inner ends of the plungers being pressed on fixed cams and the outer periphery of the plungers having a predetermined peripheral profile to enable the blade angle of attack of each blade to be varied in relation to its azimuthal position, thereby adapting to the speed of the rotary wing aircraft.

[0010] Document US3,132,696A describes a total and cyclic pitch control device for a jet-driven wing of a rotary wing aircraft, comprising: a rotor hub device rotatable with the wing of the aircraft; a duct device formed in the hub device for guiding working gas to the wing; a fixed member, which includes a device for rotatably supporting the hub device, the fixed member including a hollow cylinder device; a hollow piston device axially movable in the cylinder device; a device operatively connected to the wing and the piston device, which is used to increase the wing angle when the piston device moves in one direction; a restoring device operatively connected to the wing, which is used to reduce the wing angle and move the piston device in the opposite direction; and a duct device formed in the fixed member and connected to the duct device in the hub device for guiding working gas therein.

[0011] Document US2,663,374A describes an aircraft comprising: a fuselage; a driven member pivotally mounted on the fuselage for rotation about a substantially vertical axis; a lifting rotor having blades pivotally mounted on the member for blade pitch adjustment about a transverse axis, the rotor also being pivotally mounted on the member for tilt adjustment about the intersection of the vertical and transverse axes; a control device comprising a ball-and-socket assembly supported from the fuselage; and an operating mechanism cooperatively connecting the assembly to the rotor for adjusting the rotor blades about the transverse axis, thereby performing overall pitch control of the rotor blades; and a cyclic pitch control mechanism comprising a vertically translatable push-pull device operably connected to the control device for tilt adjustment of the assembly, thereby performing cyclic pitch control of the rotor blades.

[0012] Some of the cited prior art documents describe passive pitch angle adjustment devices. Others require complex actuator arrangements that incur additional costs, including recurring maintenance costs.

[0013] In view of the limitations and drawbacks of the prior art, an object is to provide a cyclic pitch angle adjustment device for a rotor having a rotor head and rotor blades. The cyclic pitch angle adjustment device should be relatively simple, lightweight, and inexpensive to purchase and maintain. Furthermore, the cyclic pitch angle adjustment device should provide improved efficiency of the rotor system in cross-flow conditions, with reduced bending moments and vibrations on the rotor head and rotor axis due to balanced lift. Summary of the Invention

[0014] These objects are solved by a cyclic pitch angle adjustment device comprising the features of claim 1 .

[0015] More specifically, a cyclic pitch angle adjustment device for a rotor having a rotor head and rotor blades that rotate in a rotor plane about a rotor axis includes: a base point; a bearing at a center point outside the rotor plane; a first lever connected to a first rotor blade of the rotor blades and causing the first rotor blade to rotate about a first pitch adjustment axis; a second lever connected to a second rotor blade of the rotor blades and causing the second rotor blade to rotate about a second pitch adjustment axis; a first link and a second link mechanically connecting the first lever and the second lever to the bearing at the center point so that the first link and the second link can move relative to the center point. , wherein the first link and the second link are integrally formed into a single link; a connecting member that connects the first lever, the second lever and the single link to each other in a first position; and a central link that connects the bearing to the base point, wherein the central link can be moved from a first position in which the central link forms a fixed angle with the rotor axis to a second position in which the central link forms the same fixed angle with the rotor axis, wherein the first position and the second position are different, and the central link is adapted to adjust the cyclic pitch angle of the first rotor blade and the second rotor blade to a first pitch angle in the first position and to a second pitch angle different from the first pitch angle in the second position.

[0016] Illustratively, the rotor may include a rotor hub and a rotor head, wherein the rotor hub is adapted to rotate about the rotor head. The rotor blades may be rotatably mounted on the rotor hub to allow the rotor blades' angle of attack (i.e., pitch angle) to be varied. An eccentric bearing journal may be attached to the rotor head, preferably spaced apart from the rotor axis.

[0017] The lever is preferably securely connected to the rotor blade. A connecting rod may connect the eccentric bearing journal to the lever. A counterweight may be required on the opposite side of the connection between the connecting rod and the lever. Depending on the position of the rotor blade, the distance between the connection between the connecting rod and the lever and the eccentric bearing journal changes, causing the rotor blade to deflect to compensate for this deviation. The rotor blade periodically changes its angle of attack around the circumference, with the advancing rotor blade having a smaller angle of attack and the retreating rotor blade having a relatively larger angle of attack.

[0018] The proposed periodic pitch arrangement device requires a slight increase in the complexity of the rotor system while significantly improving the aerodynamic performance.

[0019] Cyclic pitch angle regulation improves the distribution of induced air velocity and the generation of lift on the rotor blade surface. Due to the improved aerodynamics, the cruising speed of the associated rotorcraft can be increased. In addition to the advantage of increased cruising speed, efficiency is also improved due to the improved aerodynamics.

[0020] Furthermore, more uniform lift generation has a positive impact on the load and service life of the rotorcraft. This reduces load fluctuations that occur due to high speeds on the advancing rotor blades and lower flow velocities on the returning rotor blades.

[0021] Through the adjustable eccentricity, both hovering and cruising flight states can be optimized.

[0022] According to one aspect, a first movement of the center link with the bearing relative to the rotor axis causes a second movement of the first link and the second link, which second movement causes a first rotational movement of the first lever and a second rotational movement of the second lever, thereby causing a first rotation and a second rotation of the first rotor blade and the second rotor blade about the first pitch adjustment axis and the second pitch adjustment axis, respectively.

[0023] According to one aspect, the cyclic pitch angle adjustment device further comprises a balancing weight arranged at a second position, wherein the first position and the second position are on opposite sides of the rotor axis.

[0024] According to one aspect, the bearing has a first distance from the rotor axis in a first position and a second distance from the rotor axis in a second position, wherein the first distance and the second distance from the rotor axis are different.

[0025] According to one aspect, the bearing has a first distance from the rotor plane in a first position and a second distance from the rotor plane in a second position, wherein the first distance and the second distance from the rotor plane are different.

[0026] According to one aspect, the cyclic pitch angle adjustment device further comprises a motor coupled to the central link and adapted to move the central link from the first position to the second position.

[0027] According to one aspect, the cyclic pitch angle adjustment apparatus further comprises an adjustment device coupled between the motor and the central link and adapted to adjust at least one of a distance of the bearing from the rotor axis and a distance of the bearing from the rotor plane.

[0028] According to one aspect, the adjustment device further includes a guide groove that surrounds the central link and guides the central link from the first position to the second position.

[0029] According to one aspect, the adjustment device further comprises a control rod connected to the motor, wherein the motor moves the control rod such that the control rod moves the central link in the guide groove from the first position to the second position.

[0030] According to one aspect, the central link is located within the rotor head.

[0031] Furthermore, the rotor may comprise a cyclic pitch angle adjustment device as described above and rotor blades rotating in the rotor plane about the rotor axis.

[0032] Furthermore, the rotorcraft may have rotors as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the following description with reference to the accompanying drawings, embodiments are summarized by way of example. In the drawings, identical or identically functioning components or elements are marked with the same reference numerals and are therefore described only once in the following description.

[0034] - Figure 1 is a schematic diagram of an illustrative rotorcraft according to some embodiments,

[0035] - Figure 2A is a schematic diagram of an illustrative rotor with an illustrative cyclic pitch angle adjustment apparatus according to some embodiments,

[0036] - Figure 2B According to some embodiments, Figure 2A a cross-sectional view of an illustrative rotor blade with an illustrative cyclic pitch angle adjustment apparatus,

[0037] - Figure 3A is a schematic diagram of an illustrative rotor with an illustrative cyclic pitch angle adjustment apparatus having a lever extending around the rotor hub, according to some embodiments,

[0038] - Figure 3B According to some embodiments, Figure 3A a cross-sectional view of an illustrative rotor blade with an illustrative cyclic pitch angle adjustment apparatus,

[0039] - Figure 4 is a schematic diagram of an illustrative rotor having four rotor blades and an illustrative cyclic pitch angle adjustment device in accordance with some embodiments,

[0040] - Figure 5 is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus having an adjustment device according to some embodiments,

[0041] - Figure 6A is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus having an adjustment device including a guide slot, according to some embodiments,

[0042] - Figure 6B is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus having a motor and an adjustment device including a control rod, according to some embodiments,

[0043] - Figure 7A is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus having a motor and an adjustment device including a guide slot and a control rod, according to some embodiments,

[0044] - Figure 7B According to some embodiments Figure 7A A cross-sectional view of an illustrative periodic pitch angle adjustment apparatus,

[0045] - Figure 8A is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus having adjustment means for adjusting the distance from the rotor plane and the distance from the rotor axis, according to some embodiments,

[0046] - Figure 8B According to some embodiments Figure 8A A cross-sectional view of an illustrative periodic pitch angle adjustment apparatus,

[0047] - Figure 9A is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus having an adjustment device including a control rod guiding a central link in a guide slot, according to some embodiments.

[0048] - Figure 9B According to some embodiments Figure 9A A cross-sectional view of an illustrative periodic pitch angle adjustment apparatus,

[0049] - Figure 10A is a schematic diagram of an illustrative rotor with an illustrative cyclic pitch angle adjustment apparatus within a rotor head, according to some embodiments, and

[0050] - Figure 10B According to some embodiments Figure 10A A cutaway view of an illustrative rotor.

[0051] Reference Signs List

[0052] 100: Rotorcraft; 110: Multi-bladed rotor; 112, 112a, 112b: Rotor blades; 113: Rotor hub; 114: Rotor head; 115: Rotor shaft; 117: Rotor axis; 119: Rotor plane; 120: Fuselage; 123: Cockpit; 127: Rear fuselage; 130: Tail boom; 135: Horizontal stabilizer; 140: Anti-torque device; 145: Tail rotor; 150: Vertical stabilizer; 200: Cyclic pitch angle adjustment device; 205: Flight direction; 207: Rotation direction; 210: Base point; 212a: Forward rotor blade; 212b: Rear rotor blade; 220: Bearing; 223: Center point; 230, 230a, 230b, 230c, 230d: lever; 235a, 235b, 235c, 235d: pitch adjustment axis; 240, 240a, 240b, 240c, 240d: connecting rod; 250: center link; 260, 265: position; 270: connecting piece; 280: balancing weight; 290, 295: position; 510: motor; 520: adjustment device; 530a, 530b: support leg; 540: platform; 550: axis; 610, 620: distance; 630: guide groove; 710, 720: distance; 730: control lever; 740, 745: rotation direction; 810: fixed angle; 914: rotor head cover; 920: connecting rod. DETAILED DESCRIPTION

[0053] The exemplary embodiments may be included for any rotor or propeller having at least two rotor blades. For example, the embodiments may be included in a rotor or propeller of a vehicle if desired.

[0054] Figure 1 Examples of transport vehicles are shown. The transport vehicle may be an airplane, a quadcopter, a helicopter, or any other rotary wing transport vehicle. Figure 1 As shown, the transport vehicle may be a rotorcraft 100, which is exemplarily shown as a helicopter. Therefore, for simplicity and clarity, the rotorcraft 100 will be referred to as a "helicopter" 100 hereinafter.

[0055] Illustratively, helicopter 100 has a fuselage 120 forming the airframe of helicopter 100. Fuselage 120 is connected to suitable landing gear and illustratively forms a cockpit 123 and a rear fuselage 127. Rear fuselage 127 is connected to a tail boom 130.

[0056] Illustratively, helicopter 100 may have at least one multi-bladed rotor 110 for providing lift and forward or rearward thrust during operation. The at least one multi-bladed rotor 110 includes at least two rotor blades 112 mounted at an associated rotor head 114 having a rotor hub 113 to a rotor shaft 115 that rotates about an associated rotor axis 117 in a rotor plane 119 during operation of helicopter 100.

[0057] For example, helicopter 100 may include at least one anti-torque device 140 configured to provide anti-torque during operation, i.e., to counteract the torque generated by the rotation of at least one rotor 110 in order to balance helicopter 100 in yaw. If desired, anti-torque device 140 may be shrouded.

[0058] At least one anti-torque device 140 is illustratively disposed aft of tail boom 130 and may include a tail rotor 145. The aft portion of tail boom 130 may include a vertical fin 150. Tail boom 130 may illustratively be equipped with a suitable horizontal stabilizer 135.

[0059] If desired, at least one multi-bladed rotor 110 and / or tail rotor 145 may include a cyclic pitch angle adjustment device for adjusting the cyclic pitch angle of the corresponding rotor blade 112 .

[0060] Figure 2A An illustrative rotor 110 is shown with an illustrative cyclic pitch angle adjustment apparatus 200, Figure 2B Shown with Figure 2A A cross-sectional view of an illustrative rotor 110 with an illustrative cyclic pitch angle adjustment apparatus 200 is shown.

[0061] Illustratively, rotor 110 may include rotor blades 112. Rotor blades 112 may rotate about rotor axis 117 in rotor plane 119. Illustratively, rotor blades 112 may be mounted to rotor hub 113, which rotates with rotor blades 112 about rotor head 114 and, therefore, about rotor axis 117. Preferably, rotor blades 112 are rotatably mounted to rotor hub 113 to enable pitch angle variation by rotation about pitch adjustment axes 235a, 235b.

[0062] The cyclic pitch angle adjustment device 200 may be adapted to adjust the cyclic pitch angle of the rotor blades 112. Figure 2B As shown, cyclic pitch angle adjustment apparatus 200 may include a base point 210 and a bearing 220 located at a center point 223 outside of rotor plane 119 .

[0063] Illustratively, cyclic pitch angle adjustment apparatus 200 may include a first lever 230a coupled to a first rotor blade 212a of rotor blades 112 and a second lever 230b coupled to a second rotor blade 212b of rotor blades 112. First lever 230a may rotate first rotor blade 212a about a first pitch adjustment axis 235a, and second lever 230b may rotate second rotor blade 212b about a second pitch adjustment axis 235b.

[0064] For example, the cyclic pitch angle adjustment device 200 may include a first link 240a and a second link 240b. The first link 240a and the second link 240b may mechanically couple the first lever 230a and the second lever 230b to the bearing 220 at the center point 223, so that the first link 240a and the second link 240b are movable relative to the center point 223.

[0065] If necessary, Figure 2A The first link 240a and the second link 240b may be integrally formed as a single link 240. Optionally, the cyclic pitch angle adjustment device 200 may include a connector 270. The connector 270 may connect the first lever 230a, the second lever 230b, and the single link 240 to each other at the first position 290.

[0066] Illustratively, cyclic pitch angle adjustment apparatus 200 may include a center link 250 connecting bearing 220 with base point 210. Center link 250 may be moved from a first position where center link 250 forms a fixed angle with rotor axis 117 to a second position where center link 250 forms the same fixed angle with rotor axis 117, wherein the first position and the second position are different.

[0067] The fixed angle between central link 250 and rotor axis 117 may be any angle. For example, the fixed angle may be 0°. In other words, central link 250 may be parallel to rotor axis 117.

[0068] As an example, bearing 220 may have a first distance from rotor axis 117 in a first position and a second distance from rotor axis 117 in a second position, wherein the first distance and second distance from rotor axis 117 are different. As another example, bearing 220 may have a first distance from rotor plane 119 in a first position and a second distance from rotor plane 119 in a second position, wherein the first distance and second distance from rotor plane 119 are different.

[0069] If desired, the bearing 220 can be implemented as a pivot bearing with only one degree of freedom, and the central link 250 can be rotatably mounted at the base point 210 .

[0070] Central link 250 may be adapted to adjust the cyclic pitch angles of first rotor blade 212a and second rotor blade 212b to a first pitch angle in the first position and to a second pitch angle different from the first pitch angle in the second position by moving central link 250 from a first position to a second position.

[0071] For example, a first movement of center link 250 with bearing 220 relative to rotor axis 117 causes a second movement of first link 240a and second link 240b, which second movement causes a first rotational movement of first lever 230a and a second rotational movement of second lever 230b, thereby causing a first rotation and a second rotation of first rotor blade 212a and second rotor blade 212b around first pitch adjustment axis 235a and second pitch adjustment axis 235b, respectively.

[0072] Illustratively, cyclic pitch angle adjustment apparatus 200 varies the angle of attack of rotor blade 112 during rotation about rotor axis 117. During rotation of rotor blade 112 about rotor axis 117, rotor blade 112 (e.g., Figure 2A Rotor blades 212a) that move forward are sometimes referred to as forward rotor blades, whereas rotor blades 112 (e.g., Figure 2A The rotor blades 212b) are sometimes also referred to as retreating rotor blades.

[0073] For example, consider a rotorcraft having rotor 110 flying in flight direction 205 and rotor blades 112 rotating about rotor axis 117 in rotation direction 207 .

[0074] In this case, the cyclic pitch angle adjustment device 200 can be adjusted by reducing the forward rotor blade (i.e., Figure 2A The angle of attack of the first rotor blade 212a) in the position shown and increasing the angle of attack of the retreating rotor blade (i.e., Figure 2A The cyclic pitch angles of first rotor blade 212a and second rotor blade 212b are adjusted based on the angle of attack of second rotor blade 212b in the position shown. Illustratively, the cyclic pitch angles (ie, angle of attack) may be adjusted based on flight speed.

[0075] For example, an increase in flight speed from a first flight speed to a second flight speed may cause the rotor blades to advance (i.e., Figure 2A The angle of attack of the first rotor blade 212a) in the position shown is reduced from the first angle of attack to the second angle of attack and the rotor blade is retreated (i.e., in Figure 2A The angle of attack of second rotor blade 212b) in the illustrated position increases from the third angle of attack to a fourth angle of attack.

[0076] As another example, a decrease in flight speed from the second flight speed to the first flight speed may cause the angle of attack of forward rotor blades 212a to increase from the second angle of attack to the first angle of attack and the angle of attack of backward rotor blades 212b to decrease from the fourth angle of attack to the third angle of attack.

[0077] For example, cyclic pitch angle adjustment device 200 may include balancing weights 280. Balancing weights 280 may prevent imbalances during rotation of rotor 110 about rotor axis 117. These imbalances may cause serious damage to rotor 110.

[0078] Balance weight 280 may be disposed at second location 295. First location 290 and second location 295 rotate with rotor blade 112 about rotor axis 117. Preferably, first location 290 and second location 295 are on opposite sides of rotor axis 117.

[0079] Figure 3A is a schematic diagram of an illustrative rotor 110 with an illustrative cyclic pitch angle adjustment apparatus 200 having levers 230a, 230b extending about rotor hub 113, Figure 3B Is a Figure 3A A cross-sectional view of an illustrative rotor 110 with an illustrative cyclic pitch angle adjustment apparatus 200 is shown.

[0080] Figure 3A and Figure 3B The periodic pitch angle adjustment device 200 and Figure 2A and Figure 2B The cyclic pitch angle adjustment device 200 of the embodiment of the present invention differs in that the levers 230a, 230b are elongated and connected at the second position 295. Therefore, the levers 230a, 230b are identical and therefore interchangeable, which reduces the number of different parts in the rotor 110.

[0081] In addition, the counterweight 280 can be arranged at the second location 295 where the elongated levers 230a, 230b are connected. Due to the location of the elongated and connected levers 230a, 230b and the counterweight 280, Figure 3A and Figure 3B The periodic pitch angle adjustment device 200 and Figure 2A and Figure 2B Compared with the periodic pitch angle adjustment device 200, the centripetal force distribution can be improved.

[0082] Figure 4is a schematic diagram of an illustrative rotor 110 with an illustrative cyclic pitch angle adjustment device 200 and four rotor blades 112 that rotate in a rotor plane about rotor axis 117. The illustrative cyclic pitch angle adjustment device 200 may include a bearing 220 located at a center point 223 out of the rotor plane.

[0083] For example, levers 230a, 230b, 230c, 230d may be coupled to respective rotor blades 112 and cause respective rotor blades 112 to rotate about respective pitch adjustment axes 235a, 235b, 235c, 235d.

[0084] Illustratively, links 240a, 240b, 240c, 240d may mechanically couple respective levers 230a, 230b, 230c, 230d to bearing 220 at center point 223 such that links 240a, 240b, 240c, 240d may move relative to center point 223.

[0085] If necessary, the cyclic pitch angle adjustment device 200 may include a distribution element. The distribution element may establish a connection between the bearing 220 and the connecting rods 240a, 240b, 240c, 240d.

[0086] As an example, the distribution element may include a first ball joint, a second ball joint, a third ball joint, and a fourth ball joint. The first ball joint, the second ball joint, the third ball joint, and the fourth ball joint may respectively connect the first link 240a, the second link 240b, the third link 240c, and the fourth link 240d to the bearing 220 at the center point 223. If desired, four additional ball joints may respectively connect the first link 240a, the second link 240b, the third link 240c, and the fourth link 240d to the first lever 230a, the second lever 230b, the third lever 230c, and the fourth lever 230d.

[0087] For example, cyclic pitch adjustment device 200 may include a central link 250 connecting bearing 220 to a base point. For example, the base point may be located on rotor head 114.

[0088] Center link 250 may be moved from a first position where center link 250 forms a fixed angle with rotor axis 117 , to a second position where center link 250 forms the same fixed angle with rotor axis 117 .

[0089] Thus, center link 250 may be adapted to adjust the cyclic pitch angle of rotor blades 112 to a first pitch angle in a first position and to a second pitch angle different than the first pitch angle in a second position.

[0090] For example, a first movement of center link 250 with bearing 220 relative to rotor axis 117 may cause a second movement of links 240a, 240b, 240c, 240d, which second movement causes rotational movement of levers 230a, 230b, 230c, 230d, thereby causing rotor blades 112 to rotate about pitch adjustment axes 235a, 235b, 235c, 235d, respectively.

[0091] Illustratively, a motor and / or adjustment device may move the central link 250 with the bearing 220 from a first position to a second position. Figures 5 to 9B Illustrative cyclic pitch angle adjustment devices with motors and / or adjustment means are shown, which are adapted to move a central link 250 with bearings 220. For simplicity and clarity, the Figures 5 to 9B Some features are omitted from the illustrative cyclic pitch angle adjustment apparatus. For example, the connecting rod 240 and the lever 230 and the connection to the rotor blade 120 are not explicitly shown. However, if desired, Figures 5 to 9B The periodic pitch angle adjustment device can be used with Figures 2A to 4 Any periodic pitch angle adjustment device 200 is integrated with any rotor 110 .

[0092] Figure 5 is a schematic diagram of an illustrative periodic pitch angle adjustment apparatus 200 having a motor 510 and an illustrative adjustment device 520. Figure 5 As shown, the motor 510 can be coupled to the central link 250 and adapted to move the central link 250 from a first position to a second position. For example, the motor 510 can be coupled to the central link 250 via an adjustment device 520.

[0093] Adjustment device 520 coupled between motor 510 and center link 250 may be adapted to adjust at least one of a distance of bearing 220 from rotor axis 117 and a distance of bearing 220 from rotor plane 119 .

[0094] Illustratively, motor 510 can be any actuator capable of moving central link 250 from a first position to a second position via adjustment device 520. For example, motor 510 can be any rotary actuator or linear actuator that allows for precise control of angular or linear position. If desired, motor 510 can be a servo motor. Such a servo motor can include an electric motor and a sensor for position feedback.

[0095] As an example, bearing 220 may have a first distance from rotor axis 117 in a first position and a second distance from rotor axis 117 in a second position, wherein the first distance and second distance from rotor axis 117 are different. As another example, bearing 220 may have a first distance from rotor plane 119 in a first position and a second distance from rotor plane 119 in a second position, wherein the first distance and second distance from rotor plane 119 are different.

[0096] Illustratively, adjustment device 520 may include platform 540. Base point 210 of cyclic pitch angle adjustment apparatus 200 may be located on platform 540. For example, central link 250 may be fixedly attached to platform 540 at base point 210.

[0097] For example, adjustment device 520 may include legs 530a, 530b. Legs 530a, 530b may be rotatably attached to platform 540. Furthermore, leg 530a may be rotatably attached to rotor head 114, while leg 530b may be fixedly attached to motor 510.

[0098] Therefore, if Figure 5 As shown, adjustment device 520 may be adapted to simultaneously adjust the distance of bearing 220 from rotor axis 117 and the distance of bearing 220 from rotor plane 119 .

[0099] As an example, consider the case where motor 510 is a rotary actuator that rotates about axis 550. In this case, motor 510 may move platform 540 and thereby bearing 220 such that the distance of bearing 220 from rotor axis 117 and rotor plane 119 changes.

[0100] When bearing 220 is located on rotor axis 117 and furthest from rotor plane 119, cyclic pitch adjustment device 200 can adjust the pitch angles of all rotor blades to be the same, thereby optimizing the rotor for hovering flight.

[0101] When bearing 220 is located farthest from rotor axis 117 and closest to rotor plane 119, cyclic pitch adjustment device 200 can adjust the cyclic pitch angles of the advancing rotor blades and the retreating rotor blades to have the largest pitch angle difference. Thus, the rotor is optimized for fast forward flight.

[0102] Figure 6A is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus 200 having an adjustment device 520 including a guide slot 630 .

[0103] Illustratively, the cyclic pitch angle adjustment device 200 includes a central link 250. The central link 250 may connect the base point with the bearing 220 located at a central point 223.

[0104] Preferably, central link 250 is movable from first position 260 to second position 265 different from first position 260 , thereby adjusting the cyclic pitch angle of rotor blade 112 from a first pitch angle in first position 260 to a second pitch angle in second position 265 .

[0105] Illustratively, guide slot 630 may surround center link 250. If desired, guide slot 630 may guide center link 250 from first position 260 to second position 265. For example, guide slot 630 may be rotated relative to rotor axis 117 to change the eccentricity of bearing 220 (i.e., the distance from rotor axis 117 from first distance 610 to second distance 620) by moving center link 250 from first position 260 to second position 265.

[0106] Therefore, if Figure 6A As shown, bearing 220 may have a first distance 610 from rotor axis 117 in first position 260 and a second distance 620 from rotor axis 117 in second position 265, wherein first distance 610 and second distance 620 from rotor axis 117 are different. If desired, bearing 220 may have a first distance from rotor plane 119 in first position 260 and a second distance from rotor plane 119 in second position 265, wherein the first distance and second distance from rotor plane 119 are different.

[0107] For example, guide slot 630 may be formed as part of rotor head 114. For example, guide slot 630 may be a slot in a shroud of rotor head 114.

[0108] Figure 6B is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus 200 having a motor 510 and an adjustment device 520 including a control rod 730. Figure 6B As shown, motor 510 may be located on rotor head 114 spaced apart from rotor axis 117. Illustratively, motor 510 may rotate about an axis parallel to rotor axis 117. If desired, motor 510 may rotate about an axis that is tilted at an angle relative to rotor axis 117.

[0109] The control rod 730 may be connected to the motor 510 so that rotation of the motor 510 causes rotation of the control rod 730. Illustratively, the control rod 730 may surround the central link 250. For example, the control rod 730 may have a fork shape surrounding the central link 250 so that rotation of the control rod 730 moves the central link 250.

[0110] If desired, the central link 250 can be moved within the guide slot 630. For example, the motor 510 can move the control rod 730 so that the control rod 730 moves the central link 250 within the guide slot 630 from the first position 260 to the second position 265.

[0111] Figure 7A is a schematic diagram of an exemplary cyclic pitch angle adjustment device 200 having a motor 510 and an adjustment device 520, the adjustment device 520 including a guide slot 630 and a control rod 730, Figure 7B yes Figure 7A sectional view of an illustrative periodic pitch angle adjustment apparatus 200 .

[0112] Illustratively, motor 510 may be located on rotor axis 117. For example, motor 510 may be embedded in rotor head 114, such as Figure 7B If desired, motor 510 may be rotated about rotor axis 117 in first rotational direction 740 or in second rotational direction 745 .

[0113] Control rod 730 of adjustment device 520 may be connected to motor 510 such that motor 510 moves control rod 730. For example, control rod 730 may rotate about rotor axis 117 in response to rotation of motor 510 about rotor axis 117.

[0114] The guide groove 630 of the adjustment device 520 can surround the central link 250 and guide any movement of the central link 250. Figure 7B As shown, guide slot 630 may have a slope that is farthest from rotor plane 119 at the rotor axis and approaches rotor plane 119 as the distance from rotor axis 117 increases. The slope may be constant.

[0115] If desired, the slope may not be constant. Thus, the slope may vary with distance from rotor axis 117. For example, the slope may increase with increasing distance from rotor axis 117. As another example, the slope may decrease with increasing distance from rotor axis 117. As yet another example, the slope may initially increase or decrease and then decrease or increase with increasing distance from rotor axis 117.

[0116] The control rod 730 may be arcuate and surround the central link 250. For example, the control rod 730 may have a fork or a ring at the end opposite the motor 510, and the control rod 730 may use the fork or the ring to move the central link 250 in the guide slot 630. Illustratively, the motor 510 and the control rod 730 may move the central link 250 in the guide slot 630 from the first position 260 to the second position 265.

[0117] As an example, consider the case where the motor 510 rotates counterclockwise when viewed from above (i.e., Figure 7A In this case, the arcuate control rod 730 can be moved in the rotational direction 740 to move the central link 250 from the first position 260 to the second position 265.

[0118] As the center link 250 moves from the first position 260 to the second position 265, the bearing 220 connected to the center link 250 also changes position. Figure 7B As shown, bearing 220 has a first distance 610 from rotor axis 117 in first position 260 and a different second distance 620 from rotor axis 117 in second position 265. Simultaneously, bearing 220 has a first distance 710 from rotor plane 119 in first position 260 and a different second distance 720 from rotor plane 119 in second position 265.

[0119] As another example, consider the case where the motor 510 rotates clockwise when viewed from above (i.e., Figure 7A In this case, the arcuate control rod 730 can be moved in the rotational direction 745 to move the central link 250 from the second position 265 to the first position 260.

[0120] As the center link 250 moves from the second position 265 to the first position 260, the bearing 220 connected to the center link 250 also changes position. Figure 7B As shown, bearing 220 has a second distance 620 from rotor axis 117 in second position 265 and a different first distance 610 from rotor axis 117 in first position 260. Simultaneously, bearing 220 has a second distance 720 from rotor plane 119 in second position 265 and a different first distance 710 from rotor plane 119 in first position 260.

[0121] Therefore, if Figure 7A and Figure 7B As shown, motor 510 and adjustment device 520 are suitable for adjusting the distance from rotor axis 117 and the distance from rotor plane 119 simultaneously.

[0122] Figure 8A is a schematic diagram of an illustrative cyclic pitch angle adjustment apparatus 200 having an adjustment device 520 that adjusts the distance from rotor plane 119 and the distance from rotor axis 117, Figure 8B yes Figure 8A A cross-sectional view of an illustrative cyclic pitch angle adjustment apparatus.

[0123] like Figure 8B As shown, the top of rotor head 114 may be tilted relative to rotor plane 119. In particular, the distance between the top of rotor head 114 and rotor plane 119 may be greatest at rotor axis 117 and decrease with increasing distance from rotor axis 117.

[0124] Illustratively, motor 510 may be mounted on top of rotor head 114. Motor 510 may be positioned at an angle away from rotor axis 117 at the top of rotor head 114, such as Figure 8A and Figure 8B shown.

[0125] For example, the control rod 730 of the adjustment device 520 can be connected to the motor 510 so that the motor 510 moves the control rod 730. If desired, a guide slot can surround the center link 250 and guide any movement of the center link 250.

[0126] The control rod 730 may surround the central link 250. For example, the control rod 730 may have a fork or a ring at the end opposite to the motor 510, and the control rod 730 may move the central link 250 in the guide groove using the fork or the ring.

[0127] Illustratively, motor 510 and control rod 730 may move center link 250 between different positions in a guide slot on top of rotor head 114 .

[0128] For example, center link 250 may move from a first position where center link 250 forms a fixed angle 810 with rotor axis 117 to a second position where center link 250 forms the same fixed angle 810 with rotor axis 117 , where the first and second positions are different.

[0129] The fixed angle 810 between the center link 250 and the rotor axis 117 can be any angle. For example, the fixed angle 810 can be 0 degrees. In other words, the center link 250 can be parallel to the rotor axis 117 (e.g., Figure 2B 、 Figure 3B and Figure 5 As shown). Figure 8B As shown, the fixed angle 810 may be different from 0°.

[0130] As center link 250 moves between different positions, bearing 220 connected to center link 250 also changes position. For example, bearing 220 may change its distance from rotor axis 117 and its distance from rotor plane 119 simultaneously.

[0131] Bearing 220 may adjust the pitch angle of a rotor blade attached to bearing 220 via a link and lever (e.g., as described with reference to FIG. 1 ) during a change in distance from rotor axis 117 and / or from rotor plane 119. Figure 2A and Figure 2B described above).

[0132] Figure 9A is a schematic diagram of an exemplary cyclic pitch angle adjustment device 200 having an adjustment device 520 including a control rod 730 guiding a central link 250 in a guide slot 630, Figure 9B yes Figure 9A sectional view of an illustrative periodic pitch angle adjustment apparatus 200 .

[0133] like Figure 9B As shown, the top of rotor head 114 may be parallel to rotor plane 119, and motor 510 may be mounted on the top of rotor head 114. Figure 9A and Figure 9B As shown, motor 510 may be located on top of rotor head 114 at a predetermined distance from rotor axis 117 .

[0134] For example, control rod 730 of adjustment device 520 may be connected to motor 510 such that motor 510 moves control rod 730. Illustratively, guide slot 630 may be adapted to simultaneously adjust the distance of bearing 220 from rotor axis 117 and the distance of bearing 220 from rotor plane 119. If desired, guide slot 630 may have a spiral shape.

[0135] As an example, guide slot 630 may surround center link 250 and guide any movement of center link 250. Thus, movement of center link 250 in guide slot 630, and therefore movement of bearing 220, via motor 510 and control rod 730, may change the distance of bearing 220 from rotor axis 117 and the distance of bearing 220 from rotor plane 119.

[0136] As another example, control rod 730 may be attached to center link 250 and guided in helical guide slot 630. Thus, movement of center link 250 via motor 510 and movement of control rod 730 in guide slot 630 may adjust the distance of bearing 220 from rotor axis 117 and the distance of bearing 220 from rotor plane 119.

[0137] Bearing 220 may adjust the pitch angle of a rotor blade attached to bearing 220 via a link and lever during changes in distance from rotor axis 117 and / or from rotor plane 119 .

[0138] Figure 10A is a schematic diagram of an illustrative rotor 110 with an illustrative cyclic pitch angle adjustment device 200 within rotor head 114, Figure 10B yes Figure 10A A cutaway view of an illustrative rotor.

[0139] For simplicity and clarity, the rotor head cover 914 has been Figure 10A In particular, the central link 250 of the cyclic pitch angle adjustment device 200 may be located within the rotor head 114 .

[0140] Placing cyclic pitch angle adjustment device 200 within rotor head 114 may improve the aerodynamics of rotor 110 and protect cyclic pitch angle adjustment device 200 from weather and pollution, which may increase robustness, reduce degradation, and lower maintenance costs.

[0141] Illustratively, cyclic pitch angle adjustment apparatus 200 may include base point 210 and bearing 220 located at center point 223 outside rotor plane 119. As an example, rotor plane 119 may be located between center point 223 and rotor head cover 914.

[0142] like Figure 10A and Figure 10B As shown, the first lever and the second lever may be integrally formed as a single lever 230. Single lever 230 may be connected to rotor blade 112. Single lever 230 may rotate first rotor blade 112 about a first pitch adjustment axis 235a and rotate second rotor blade 112 about a second pitch adjustment axis 235b.

[0143] Illustratively, the first link and the second link may be integrally formed as a single link 240. A connector 270 may connect the single lever 230 and the single link 240 to each other at a first position 290. The single link 240 may mechanically couple the single lever 230 to the bearing 220 at the center point 223 such that the single link 240 is movable relative to the center point 223.

[0144] For example, cyclic pitch adjustment device 200 may include a central link 250 connecting bearing 220 to base point 210. Central link 250 may be movable from a first position where central link 250 forms a fixed angle with rotor axis 117 to a second position 265 where central link 250 forms the same fixed angle with rotor axis 117. For example, central link 250 may be movably mounted at link 920.

[0145] Thus, center link 250 may be adapted to adjust the cyclic pitch angle of first and second rotor blades 112 to a first pitch angle in a first position and to a second pitch angle different than the first pitch angle in a second position.

[0146] If desired, cyclic pitch angle adjustment device 200 may include a counterweight. The counterweight may be arranged at the second position. First position 290 and second position may be on opposite sides of rotor axis 117. As an example, a single lever 230 may extend on the side of rotor axis 117 opposite first position 290.

[0147] It should be noted that the above embodiments are only used to illustrate feasible embodiments of the present invention and are not intended to limit the present invention thereto. On the contrary, various modifications and variations of the above embodiments are possible.

[0148] For example, Figures 2A to 3B First lever 230a and second lever 230b are each shown as separate levers that are connected to first rotor blade 112 and second rotor blade 112 and rotate first rotor blade 112 about first pitch adjustment axis 235a and second pitch adjustment axis 235b, respectively. However, if desired, first lever 230a and second lever 230b may be integrally formed as a single lever.

[0149] In addition, if necessary, Figures 5 to 9B The motor 510 and adjustment device 520 shown can be used with Figures 2A to 4 and Figure 10A and Figure 10B Any rotor 110 is combined and integrated therein.

Claims

1. A periodic pitch angle adjustment device (200) for a rotor (110), the rotor having a rotor head (114) and rotor blades (112), the rotor blades (112) rotating around a rotor axis (117) in a rotor plane (119), the periodic pitch angle adjustment device (200) comprising: basis points (210); a bearing (220) located at a center point (223) outside the rotor plane (119); a first lever (230a) connected to a first rotor blade (212a) of the rotor blades (112) and causing the first rotor blade (212a) to rotate about a first pitch adjustment axis (235a); a second lever (230b) connected to a second rotor blade (212b) of the rotor blades (112) and causing the second rotor blade (212b) to rotate about a second pitch adjustment axis (235b); a first link (240a) and a second link (240b) mechanically coupling the first lever (230a) and the second lever (230b) to the bearing (220) at the center point (223), such that the first link (240a) and the second link (240b) are movable relative to the center point (223), wherein the first link (240a) and the second link (240b) are integrally formed as a single link (240); a connecting member (270) connecting the first lever (230a), the second lever (230b), and the single link (240) to each other at a first position (290); and A center link (250) connects the bearing (220) to the base point (210), wherein the center link (250) is movable from a first position (260) in which the center link (250) forms a fixed angle (810) with the rotor axis (117) to a second position (265) in which the center link (250) forms the same fixed angle (810) with the rotor axis (117), wherein the first position (260) and the second position (265) are different, and wherein the center link (250) is adapted to adjust the cyclic pitch angles of the first rotor blade (212a) and the second rotor blade (212b) to a first pitch angle in the first position (260) and to a second pitch angle different from the first pitch angle in the second position (265).

2. The periodic pitch angle adjustment device (200) according to claim 1, wherein: A first movement of the central link (250) with the bearing (220) relative to the rotor axis (117) causes a second movement of the first link (240a) and the second link (240b), which second movement causes a first rotational movement of the first lever (230a) and a second rotational movement of the second lever (230b), thereby causing a first rotation and a second rotation of the first rotor blade (212a) and the second rotor blade (212b) around the first pitch adjustment axis (235a) and the second pitch adjustment axis (235b), respectively.

3. The periodic pitch angle adjustment device (200) according to claim 1, further comprising: A balance weight (280) is disposed at a second position (295), wherein the first position (290) and the second position (295) are on opposite sides of the rotor axis (117).

4. The periodic pitch angle adjustment device (200) according to claim 1, wherein: The bearing (220) has a first distance (610) from the rotor axis (117) in the first position (260) and a second distance (620) from the rotor axis (117) in the second position (265), wherein the first distance (610) and the second distance (620) from the rotor axis (117) are different.

5. The periodic pitch angle adjustment device (200) according to claim 1, wherein: The bearing (220) has a first distance (710) from the rotor plane (119) in the first position (260) and a second distance (720) from the rotor plane (119) in the second position (265), wherein the first distance (710) and the second distance (720) from the rotor plane (119) are different.

6. The periodic pitch angle adjustment device (200) according to claim 1, further comprising: A motor (510) is coupled to the central link (250) and is adapted to move the central link (250) from the first position (260) to the second position (265).

7. The periodic pitch angle adjustment device (200) according to claim 6, further comprising: An adjustment device (520) is coupled between the motor (510) and the center link (250) and is adapted to adjust at least one of a distance of the bearing (220) from the rotor axis (117) and a distance of the bearing (220) from the rotor plane (119).

8. The periodic pitch angle adjustment device (200) according to claim 7, wherein: The regulating device (520) further includes: A guide groove (630) surrounds the central link (250) and guides the central link (250) from the first position (260) to the second position (265).

9. The periodic pitch angle adjustment device (200) according to claim 8, wherein: The regulating device (520) further includes: A control rod (730) connected to the motor (510), wherein the motor (510) moves the control rod (730) so that the control rod (730) moves the central link (250) from the first position (260) to the second position (265) in the guide slot (630).

10. The periodic pitch angle adjustment device (200) according to claim 1, wherein: The central connecting rod (250) is located inside the rotor head (114).

11. A rotor (110), comprising: Rotor blades (112) rotating about a rotor axis (117) in a rotor plane (119); as well as The periodic pitch angle adjustment device (200) according to claim 1.

12. A rotorcraft (100) comprising a rotor (110) according to claim 11.

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