Variable pitch connecting structure of open rotor engine and aircraft with same

Abstract

The application discloses an open rotor engine variable-pitch connecting structure and an aircraft with the same, which comprises a hub, a plurality of blades and a modularly designed integral variable-pitch actuating mechanism. The hub is provided with a plurality of blade sleeves on the outer periphery. The blades are detachably arranged in the corresponding blade sleeves through the blade roots. The variable-pitch actuating mechanism comprises a dial located in the hub cavity. The outer periphery of the dial is concave to form a U-shaped groove. The eccentric pins of the plurality of blades are arranged in the U-shaped groove. When the internal components of the variable-pitch actuating mechanism slide along the axial direction, the blades are driven to deflect to change the pitch through the friction between the U-shaped groove and the eccentric pins. A plurality of lace grooves are arranged on the wall surface of one side of the U-shaped groove. When the variable-pitch actuating mechanism is rotated, the plurality of lace grooves correspond to the plurality of eccentric pins one by one, so that the variable-pitch actuating mechanism is pulled out along the axial direction as a whole. When the variable-pitch actuating mechanism is disassembled, the hub and the blades do not need to be disassembled synchronously, so that the disassembly and assembly process is simple, the maintenance cost is low, and the blades can be disassembled and replaced in the field.

Description

Technical Field

[0001] This invention relates to the field of gas turbine engine technology, and in particular, to a variable pitch connection structure for an open rotor engine. Furthermore, this invention also relates to an aircraft having the aforementioned variable pitch connection structure for an open rotor engine. Background Technology

[0002] A propfan engine, also known as an open rotor engine, is a gas turbine engine that uses the power output shaft of a power turbine to drive a propfan to generate thrust. It is a new type of engine between a turboprop and a turbofan, and is also called a propfan engine or a ductless fan engine. An open fan is a type of impeller machine that generates thrust (or pull) without an outer casing. The blades of an open fan rotate around their respective blade axes to adapt to different airflow conditions. Open rotor engines achieve optimal performance combinations under different operating conditions by designing blade pitch adjustment patterns.

[0003] Similar to propellers, open propellers require a pitch-changing mechanism to adjust the pitch. High-power propellers generally employ a single-cylinder, dual-cylinder hydraulic pitch-changing structure with counterweight. This structure mainly consists of a hub, root, cylinder, piston, shift sleeve, and oil supply pipe. An eccentric pin on the bottom of the root is placed in a groove in the shift sleeve, forming a crank-slider structure with the shift sleeve and piston. The piston-shift sleeve moves axially, causing the eccentric pin to rotate around the blade's axis, thus changing the blade pitch. The piston divides the cylinder into a large-pitch chamber and a small-pitch chamber. Oil is supplied to both chambers via the oil supply pipe. A control device adjusts the oil pressure in both chambers, using the pressure difference to generate axial force that drives the piston axially. This force, in turn, drives the eccentric pin at the root to rotate, achieving blade pitch angle adjustment.

[0004] For example, in the existing patent "CN 104554708 A Pitch Variable Actuator of an Electronic Pitch Variable Device for a Propeller", two guide rods are located inside the cylinder cavity, with their ends installed on the propeller and the cylinder wall respectively, and the piston passing through the middle. This structure has several drawbacks. First, it requires an additional reciprocating dynamic sealing structure and seals, resulting in a complex overall structure. Furthermore, the seals require high precision machining and are difficult to assemble. Second, during assembly, the cylinder, piston, propeller hub, shift sleeve, and propeller blades must be assembled together. If any component needs replacement or inspection, the entire pitch variable mechanism, including the propeller blades, must be disassembled. This disassembly and assembly process is extremely cumbersome, leading to high maintenance costs and hindering propeller blade replacement in the field. Additionally, after prolonged operation and impact loads, the shift sleeve groove is prone to deformation under pitch force, resulting in decreased pitch adjustment accuracy. The shift sleeve is a component requiring frequent maintenance and inspection, and its integrated structure further increases maintenance costs. Summary of the Invention

[0005] This invention provides an open rotor engine pitch connection structure and an aircraft having the same, to solve the technical problems of existing structures, such as cumbersome disassembly and assembly processes, high maintenance costs, and difficulty in replacing propeller blades in the field.

[0006] The technical solution adopted in this invention is as follows: An open rotor engine pitch-changing connection structure includes: a hollow annular rotor hub, multiple blades, and a pitch-changing actuator modularly designed as an integral unit; the outer periphery of the rotor hub has multiple circumferentially evenly spaced blade sleeves extending radially, each blade sleeve corresponding to one of the blades, and each blade sleeve has an installation channel connecting to the rotor hub cavity at the center of the rotor hub; each blade includes a blade body, a blade root, and an eccentric pin connected sequentially along the axial direction, the blade being detachably mounted in the installation channel of the corresponding blade sleeve through its blade root, and the eccentric pin extending into the rotor hub cavity; the pitch-changing actuator... The traveling mechanism is connected to the propeller hub along the axial direction. It includes a dial located in the propeller hub cavity. The outer periphery of the dial is concave to form an annular U-shaped groove. The eccentric pins of multiple propeller blades are installed in the U-shaped groove. When the internal components of the pitch-changing actuator slide along the axial direction, the friction between the U-shaped groove and the eccentric pin drives the propeller blades to deflect and change the pitch. On one side wall of the U-shaped groove, there are multiple circumferentially spaced and connected lace grooves corresponding to multiple eccentric pins. When the pitch-changing actuator is rotated, the multiple lace grooves correspond one-to-one with multiple eccentric pins, so that the pitch-changing actuator can be pulled out as a whole along the axial direction.

[0007] Furthermore, the open rotor engine pitch-changing connection structure also includes a paddle shaft support plate; the pitch-changing actuator also includes a cylinder, a piston, and a mounting oil supply shaft assembly. The cylinder is connected to the front end face of the rotor hub, the paddle shaft support plate is connected to the rear end face of the rotor hub, and the mounting oil supply shaft assembly is axially supported by the cylinder and the paddle shaft support plate; the piston is mounted on the outer circle of the front end of the mounting oil supply shaft assembly and is located in the cylinder, so as to divide the inner cavity of the cylinder into a large-pitch oil chamber and a small-pitch oil chamber arranged axially in sequence. The mounting oil supply shaft assembly is provided with a first oil inlet channel and a second oil inlet channel extending axially, and the first oil inlet channel is connected to the large-pitch oil chamber, and the second oil inlet channel is connected to the small-pitch oil chamber; the paddle is mounted on the outer circle of the middle section of the mounting oil supply shaft assembly.

[0008] Furthermore, the oil supply shaft assembly includes a hollow, axially arranged shift sleeve shaft, a locking nut, a connecting key, and a shift sleeve sleeve. The outer circumference of the shift sleeve shaft's front end is machined with an external thread, and the outer circumference of the middle section of the shift sleeve shaft is machined with a convex limiting step. The locking nut and piston are sequentially mounted on the outer circumference of the shift sleeve shaft's front end, with the locking nut located at the front end of the piston. The connecting key is installed between the piston and the shift sleeve shaft. The shift sleeve sleeve and dial are sequentially mounted on the outer circumference of the middle section of the shift sleeve shaft, with the shift sleeve sleeve located between the piston and the dial. The dial is axially limited by the limiting step, and the piston, shift sleeve sleeve, and dial are fixed to the shift sleeve shaft by the locking nut.

[0009] Furthermore, the oil supply shaft assembly also includes an adjusting shim installed on the outer circle of the shift sleeve shaft. The adjusting shim is located between the piston and the shift sleeve sleeve to adjust the feather angle position of the blade. The oil supply shaft assembly also includes a hydraulic oil pipe installed axially inside the shift sleeve shaft, and an oil pipe support ring for supporting the hydraulic oil pipe. The hydraulic oil pipe has a first oil inlet channel and a second oil inlet channel. The oil pipe support ring is installed on the outer circle of the rear end of the hydraulic oil pipe and is tightened in the inner hole of the shift sleeve shaft.

[0010] Furthermore, the dial includes a dial sleeve retainer and a dial sleeve, which are sequentially mounted on the outer circle of the oil supply shaft assembly along the axial direction, and a connecting pin for fixing the two together; the dial sleeve retainer is disc-shaped and is used to restrict the eccentric pin of the blade from passing through along the axial direction; the dial sleeve includes a sleeve whose first end is connected to the dial sleeve retainer by the connecting pin, and multiple lace pieces fixedly connected to the outer circle of the second end of the sleeve, the multiple lace pieces are evenly spaced along the circumference so that a lace groove is formed between two adjacent lace pieces, and the gap between the lace pieces and the dial sleeve retainer also forms a U-shaped groove.

[0011] Furthermore, the oil supply shaft assembly also includes multiple axially arranged guide rods, which are spaced apart circumferentially along the dial. The front end of each guide rod is fixedly connected to an oil cylinder, and the rear end of each guide rod is fitted with a dial sleeve.

[0012] Furthermore, each blade root has two inner bearing raceways arranged axially and circumferentially concave on its outer circumference, and the inner wall of the blade sleeve mounting channel has two outer bearing raceways corresponding to each other. The outer wall of the blade sleeve also has ball bearing mounting holes that connect the two outer bearing raceways respectively, and bearing plugs for sealing the ball bearing mounting holes. The outer bearing balls enter the two raceway rings composed of the inner and outer bearing raceways through the ball bearing mounting holes, and form two ball bearings with the cage installed between the blade root and the blade sleeve.

[0013] Furthermore, each paddle sleeve is equipped with a support ring at its top, and the outer circumference of the paddle blade is also convex to form a support step. The paddle blade is supported on the support ring by the support step, and the lifting of the paddle blade causes the inner raceway of the two bearing rings to be lifted and misaligned with the corresponding outer raceway of the bearing, thereby ensuring that the two bearing balls are in a tight fit. A paddle root adjustment pad is also installed between the support ring and the top of the corresponding paddle sleeve, so that the thickness of the paddle root adjustment pad is adjusted to ensure that the two bearing balls are in a tight fit.

[0014] Furthermore, the rear wall of the propeller hub is provided with a mounting hole that connects to the propeller hub cavity, and a one-way exhaust valve is installed in the mounting hole; a counterweight arm is also installed on the outer circle of each blade, the counterweight arm is located outside the propeller hub, and a counterweight block is connected to the cantilever end of the counterweight arm; the wall of the oil cylinder is also provided with an oil drain hole that connects to its inner cavity, and an oil drain valve is installed in the oil drain hole.

[0015] According to another aspect of the invention, an aircraft is also provided having an open rotor engine pitch connection structure as described above.

[0016] The present invention has the following beneficial effects: In the open rotor engine pitch-changing connection structure of the present invention, since the outer periphery of the dial has a U-shaped groove, and the eccentric pins of multiple blades are installed in the U-shaped groove, when the internal components of the pitch-changing actuator slide axially under hydraulic pressure, it drives the dial to slide axially synchronously. Thus, through the friction between the U-shaped groove and the eccentric pins, the blades can be deflected to achieve pitch change. Simultaneously, multiple circumferentially spaced and connected lace grooves are provided on one side of the U-shaped groove corresponding to the multiple eccentric pins. When the pitch-changing actuator needs to be disassembled for maintenance and replacement, it is only necessary to first loosen the connection between the pitch-changing actuator and the blade hub, and then rotate the pitch-changing actuator so that the multiple lace grooves correspond one-to-one with the multiple eccentric pins. Figure 6-8 As shown in the diagram, the pitch actuator can be pulled out as a whole along the axial direction. Disassembling the pitch actuator does not require simultaneous disassembly of the rotor hub and blades, simplifying the disassembly and assembly process and facilitating the replacement of easily worn parts inside the actuator, greatly improving maintainability. Furthermore, because the pitch actuator adopts a modular design as a whole, its structure is simple, easy to disassemble and assemble, and has low maintenance costs. It can also be assembled separately from the rotor hub and blades, further improving assembly efficiency and demonstrating significant potential for engineering applications. In addition, the mounting channels for the blades and blade sleeves are detachable, allowing the blades to be disassembled without disassembling the rotor hub, enabling blade disassembly and replacement in the field.

[0017] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a cross-sectional front view schematic diagram of the variable pitch connection structure of an open rotor engine according to a preferred embodiment of the present invention; Figure 2 yes Figure 1 Schematic diagram of the spatial structure of the central propeller hub; Figure 3 yes Figure 1 Schematic diagram of the spatial structure of the middle blade; Figure 4 yes Figure 1 Schematic diagram of the spatial structure of a medium-pitch actuator; Figure 5 yes Figure 4Schematic diagram of the spatial structure of the middle shifter; Figure 6 This is a diagram of the fully feathered state of the variable pitch actuator when it is disassembled. Figure 7 This is a diagram showing the state of the eccentric pin disengaging from the lace groove when the variable pitch actuator is disassembled. Figure 8 This is a diagram showing the state of the eccentric pin disengaging from the lace groove when disassembling the variable pitch actuator; Figure 9 This is a diagram showing the state of the propeller blades as they fall to install the bearing balls; Figure 10 This is a diagram showing the state when the propeller blade is lifted to install the support ring.

[0019] Legend: 1. Propeller hub; 11. Propeller sleeve; 12. Ball bearing mounting hole; 13. Bearing plug; 2. Blade; 21. Eccentric pin; 22. Spherical plain bearing; 3. Dial; 302. Decorative groove; 31. Dial sleeve retainer; 32. Dial sleeve; 322. Decorative trim; 33. Connecting pin; 4. Sleeve shaft support plate; 5. Hydraulic cylinder; 51. Hydraulic cylinder cover; 6. Piston; 7. Install the oil supply shaft assembly; 71. Displacement sleeve shaft; 72. Locking nut; 73. Connecting key; 74. Displacement sleeve; 75. Adjusting shim; 76. Hydraulic oil pipe; 77. Oil pipe support ring; 78. Guide rod; 81. Bearing balls; 82. Cage; 83. Support ring; 84. Paddle root adjusting shim; 91. One-way exhaust valve; 92. Counterweight arm; 93. Counterweight block; 94. Oil drain valve; 95. O-ring seal. Detailed Implementation

[0020] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below. Examples of the embodiments 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.

[0021] Those skilled in the art will understand that, unless specifically stated otherwise, the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, and / or combinations thereof. It should be understood that when we say a component is "connected" to another component, it can be directly connected to the other component or connected via an intermediate component. The term "and / or" as used herein includes all or any unit and all combinations of one or more associated listed items. The terms "first" and "second," etc., in this specification and claims are used to distinguish different objects, not to describe a particular order.

[0022] Reference Figure 1 and Figure 3 A preferred embodiment of the present invention provides a variable pitch connection structure for an open rotor engine, comprising: a hollow annular rotor hub 1, multiple blades 2, and a variable pitch actuator modularly designed as a whole. The outer periphery of the rotor hub 1 has multiple circumferentially evenly spaced blade sleeves 11 extending radially, each blade sleeve 11 corresponding to one of the multiple blades 2, and each blade sleeve 11 has an installation channel connecting to the rotor hub 1 cavity at its center. Each blade 2 includes a blade body, a blade root, and an eccentric pin 21 connected sequentially along the axial direction. The blade 2 is detachably mounted in the installation channel of the corresponding blade sleeve 11 through its blade root, and the eccentric pin 21 extends into the rotor hub 1 cavity. The variable pitch actuator is axially connected to the rotor hub 1. It includes a dial 3 located inside the cavity of the rotor hub 1. The outer periphery of the dial 3 is concave to form an annular U-shaped groove. The eccentric pins 21 of multiple rotor blades 2 are installed in the U-shaped groove. When the internal components of the variable pitch actuator slide along the axial direction, the friction between the U-shaped groove and the eccentric pins 21 drives the rotor blades 2 to deflect and change the pitch. On one side of the wall of the U-shaped groove, there are multiple circumferentially spaced and connected lace grooves 302 corresponding to the multiple eccentric pins 21. When the variable pitch actuator is rotated, the multiple lace grooves 302 correspond one-to-one with the multiple eccentric pins 21, so that the variable pitch actuator can be pulled out as a whole along the axial direction.

[0023] In the open rotor engine pitch-changing connection structure of the present invention, since the outer periphery of the dial 3 has a U-shaped groove, and the eccentric pins 21 of the multiple blades 2 are installed in the U-shaped groove, when the internal components of the pitch-changing actuator slide axially under hydraulic pressure, it drives the dial 3 to slide axially synchronously. Thus, through the friction between the U-shaped groove and the eccentric pins 21, the blades 2 can be deflected to achieve pitch change. Simultaneously, on one side of the U-shaped groove, there are multiple circumferentially spaced and connected lace grooves 302 corresponding to the multiple eccentric pins 21. When the pitch-changing actuator needs to be disassembled for maintenance and replacement, simply loosen the connection between the pitch-changing actuator and the rotor hub 1, and then rotate the pitch-changing actuator so that the multiple lace grooves 302 correspond one-to-one with the multiple eccentric pins 21, such as... Figure 6-8 As shown in the diagram, the pitch actuator can be pulled out as a whole along the axial direction. When disassembling the pitch actuator, it is not necessary to disassemble the hub 1 and blade 2 simultaneously, thus simplifying the disassembly and assembly process, making it easy to replace the consumable parts inside the pitch actuator, and greatly improving maintainability. At the same time, since the pitch actuator adopts a modular design as a whole, the structure is simple, easy to disassemble and assemble, and has low maintenance costs. It can also be assembled separately from the hub 1 and blade 2 to further improve assembly efficiency and has great potential for engineering applications. In addition, the mounting channel between blade 2 and blade sleeve 11 is detachable, so blade 2 can be disassembled without disassembling the hub 1, allowing for disassembly and replacement of blade 2 in the field.

[0024] Optionally, such as Figure 1 and Figure 4 As shown, the open rotor engine pitch-changing connection structure also includes a paddle shaft support plate 4. The pitch-changing actuator also includes a cylinder 5, a piston 6, and a mounting oil supply shaft assembly 7. The cylinder 5 is connected to the front end face of the rotor hub 1, and the paddle shaft support plate 4 is connected to the rear end face of the rotor hub 1. The mounting oil supply shaft assembly 7 is axially supported by the cylinder 5 and the paddle shaft support plate 4. The piston 6 is mounted on the outer circle of the front end of the mounting oil supply shaft assembly 7 and is located in the cylinder 5, dividing the inner cavity of the cylinder 5 into a large-pitch oil chamber and a small-pitch oil chamber arranged sequentially in the axial direction. The mounting oil supply shaft assembly 7 has a first oil inlet channel and a second oil inlet channel extending axially, respectively, with the first oil inlet channel connecting to the large-pitch oil chamber and the second oil inlet channel connecting to the small-pitch oil chamber. The paddle 3 is mounted on the outer circle of the middle section of the mounting oil supply shaft assembly 7. In this optional scheme, as shown... Figure 1 As shown, the rear stop of the hydraulic cylinder 5 is fitted with the propeller hub 1 with a small clearance and is fastened with bolts; the hydraulic cylinder 5 includes a hydraulic cylinder cover 51 and a hydraulic cylinder body that cooperate with each other. The two are connected by bolts and an O-ring seal is provided at the connection point to seal it. The hydraulic cylinder cover 51 and the hydraulic cylinder body together form a variable pitch oil chamber; the wall surface of the hydraulic cylinder 5 is also provided with an oil drain hole that connects to its inner cavity. An oil drain valve 94 is installed in the oil drain hole to remove the lubricating oil remaining in the hydraulic cylinder 5 during disassembly and to seal it during operation.

[0025] In this optional solution, such as Figure 1As shown, the oil supply shaft assembly 7 includes a hollow, axially arranged dial sleeve shaft 71, a locking nut 72, a connecting key 73, and a dial sleeve 74. The outer circumference of the front end of the dial sleeve shaft 71 is machined with external threads, and the outer circumference of the middle section of the dial sleeve shaft 71 is machined with a protruding limiting step. The locking nut 72 and the piston 6 are sequentially mounted on the outer circumference of the front end of the dial sleeve shaft 71, with the locking nut 72 located at the front end of the piston 6. The connecting key 73 is installed between the piston 6 and the dial sleeve shaft 71. The shift sleeve 74 and the shift disc 3 are sequentially installed on the outer circle of the middle section of the shift shaft 71. The shift sleeve 74 is located between the piston 6 and the shift disc 3. The shift disc 3 is axially limited against the limiting step. The piston 6, the shift sleeve 74 and the shift disc 3 are fixed on the shift shaft 71 by the locking nut 72, thereby preventing the piston 6, the shift sleeve 74 and the shift disc 3 from rotating relative to the shift shaft 71. The rear end of the shift shaft 71 is supported by the shift shaft support plate 4.

[0026] Preferably, such as Figure 1 As shown, the oil supply shaft assembly 7 also includes an adjusting shim 75 mounted on the outer circumference of the shift sleeve shaft 71. The adjusting shim 75 is located between the piston 6 and the shift sleeve 74 to adjust the feathering angle position of the blade 2. The reversing angle position can also be adjusted by grinding the end face of the maximum reversing limit position of the hydraulic cylinder. The oil supply shaft assembly 7 also includes a hydraulic oil pipe 76 axially mounted within the shift sleeve shaft 71, and an oil pipe support ring 77 for supporting the hydraulic oil pipe 76. The hydraulic oil pipe 76 has a first oil inlet channel and a second oil inlet channel. The oil pipe support ring 77 is mounted on the outer circumference of the rear end of the hydraulic oil pipe 76 and is tightly fitted into the inner hole of the shift sleeve shaft 71. In this preferred embodiment, as... Figure 1 As shown, the hydraulic oil pipe 76 is a hollow tube with small-pitch oil holes milled in its wall. It is threaded onto the shift sleeve shaft 71 and sealed with an O-ring. It provides pitch-changing hydraulic oil to the entire pitch-changing actuator and can move axially with the shift sleeve shaft 71. The internal central hole supplies oil to the large-pitch oil chamber, and the oil holes in the pipe wall supply oil to the small-pitch oil chamber. The rear end of the hydraulic oil pipe 76 passes through the reducer and is installed in the displacement sensor in the pitch controller. The pitch-changing hydraulic oil is supplied by the reducer, and the sensor in the pitch controller provides a displacement signal, which can be used to feedback blade angle information. The overall structure of the pitch-changing actuator is shown in [reference needed]. Figure 4 As shown.

[0027] Optionally, such as Figure 1 and Figure 5As shown, the dial 3 includes a dial sleeve retainer 31 and a dial sleeve 32, which are sequentially mounted axially on the outer circle of the oil supply shaft assembly 7, and a connecting pin 33 for fixing the two together. The dial sleeve retainer 31 is disc-shaped and is used to restrict the eccentric pin 21 of the blade 2 from passing through axially. The dial sleeve 32 includes a sleeve whose first end is connected to the dial sleeve retainer 31 via the connecting pin 33, and multiple decorative edges 322 fixedly connected to the outer circle of the second end of the sleeve. The multiple decorative edges 322 are evenly spaced circumferentially so that a decorative groove 302 is formed between two adjacent decorative edges 322, and the gap between the decorative edges 322 and the dial sleeve retainer 31 also forms a U-shaped groove. In this optional embodiment, a spherical bearing 22 is also provided on the eccentric pin 21 at the root of the blade 2. The spherical bearing 22 rolls in the U-shaped groove of the dial 3, thereby causing the piston 6 to drive the dial 3 to move axially to achieve the purpose of changing the pitch; as Figure 5 As shown, the shift sleeve 32 is designed with 6 decorative edges 322. The spacing between the decorative edges 322 is sufficient for the eccentric pin 21 and the joint bearing 22 to pass through, which facilitates the disassembly of the variable pitch actuator without removing the blade 2.

[0028] Preferably, such as Figure 1 and Figure 4 As shown, the oil supply shaft assembly 7 also includes multiple axially arranged guide rods 78. These guide rods 78 are spaced apart circumferentially along the dial 3, with the front end of each guide rod 78 fixedly connected to the hydraulic cylinder 5, and the rear end of each guide rod 78 passing through a dial sleeve retainer 31. In actual design, the guide rods 78 pass through the dial sleeve retainer 31 via bushings. This prevents relative rotation between the dial sleeve 32 and the hydraulic cylinder 5, and guides the dial sleeve 32 to move back and forth axially, preventing the dial sleeve 32 and hydraulic cylinder 5 from deviating from their axial direction and causing cylinder scoring. In this preferred embodiment, as... Figure 1 As shown, since the guide rod 78 of the variable pitch actuator is located inside the hub cavity, the sealing requirements of the contact surface between the guide rod 78 and the gear sleeve retainer 31 are not high. Therefore, the overall structure of the variable pitch actuator is simple, the requirements for the machining accuracy of the parts are low, the assembly difficulty is low, and it is easy to process and assemble.

[0029] Optionally, such as Figures 1-3 As shown, the propeller hub 1 is a six-sleeve rotationally symmetric structure (see attached diagram). Figure 1 Only one blade sleeve is shown. During operation, it rotates around the axis of the blade hub 1, while providing an installation interface for the blade 2 and supporting the blade 2 to rotate around the axis of the blade sleeve for pitch variation. The rear flange of the blade hub 1 is connected to the blade shaft (not shown in the figure) through bolts, which transmits load and torque and is the main load-bearing structural component of the pitch-variable actuator.

[0030] Furthermore, such as Figure 1 and Figure 3As shown, the blade 2 is composed of a composite material blade body and a metal blade root. An O-ring 95 is provided between the blade root and the corresponding blade sleeve to seal the grease in the blade hub cavity. A counterweight arm 92 is also installed on the outer circumference of each blade 2. The counterweight arm 92 is located outside the blade hub 1. There is a positioning pin above the blade root. The positioning pin passes through the positioning pin hole of the blade root and the positioning pin of the counterweight arm 92, which plays the role of positioning the counterweight arm 92 and transmitting torque. The cantilever end of the counterweight arm 92 is also connected to a counterweight block 93. The weight of the counterweight block 93 is adjusted to adapt to the centrifugal torque required for pitch change. The eccentric pin 21 designed below the blade root, together with the shift sleeve 32 and shift sleeve retainer 31 of the pitch actuator, forms a slider mechanism, which converts the axial movement of the shift sleeve 32 along the axis of the blade hub 1 into the angular movement of the blade 2 along the axis of the blade root, thereby realizing the pitch function of the blade. The spherical bearing 22 at the end of the eccentric pin 21 can withstand the pitch force of the blade 2 and reduce the friction between the eccentric pin 21 and the shift sleeve 32 and shift sleeve retainer 31. The spherical bearing 22 is fastened with an elastic retaining ring.

[0031] In this optional solution, such as Figure 1 As shown, each blade 2 has two inner bearing raceways arranged axially and circumferentially concave on the outer circumference of its root. The inner wall of the mounting channel of the blade sleeve 11 has two corresponding outer bearing raceways. The outer wall of the blade sleeve 11 also has ball bearing mounting holes 12 that connect to the two outer bearing raceways, and bearing caps 13 for sealing the ball bearing mounting holes 12. The outer bearing balls 81 enter the two raceway rings formed by the inner and outer bearing raceways through the ball bearing mounting holes 12, forming two ball bearings with the cage 82 installed between the blade root and blade sleeve 11. In this optional embodiment, the bearing balls 81 are fixed by a cage 82 made of nylon soft material with slits. The ball bearing mounting holes 12 are used to install the bearing balls 81 and also to inject grease to lubricate the ball bearings. The ball bearing mounting holes 12 are sealed by bearing caps 13 with end-face sealing O-rings to prevent grease leakage during operation. The rear wall of the propeller hub 1 is also provided with a mounting hole that connects to the cavity of the propeller hub 1. A one-way exhaust valve 91 is installed in the mounting hole. The one-way exhaust valve 91 automatically starts to release pressure when the pressure inside the propeller hub cavity is higher than the external pressure. The opening pressure is 0.034MPa, and external air cannot enter the propeller hub cavity. The purpose of installing the one-way exhaust valve 91 is to balance the pressure inside the propeller hub cavity with the external environment and prevent the pressure inside the cavity from rising due to altitude, hydraulic oil evaporation, etc., which would have an adverse effect on the lubricating oil and grease seal inside the cavity.

[0032] Preferably, such as Figure 1As shown, each blade sleeve 11 is also equipped with a support ring 83 at its top. The outer circumference of the blade 2 also protrudes to form a support step. The blade 2 is supported by the support step and lifted onto the support ring 83. The lifting of the blade 2 causes the inner raceways of the two bearing rings to be misaligned relative to the corresponding outer raceway portions, thus ensuring the two bearing balls 81 are in a tightly fitted state. In this preferred embodiment, the support ring 83 is used to support the blade 2, preventing the blade 2 from falling and causing the bearing balls 81 to disengage from the slideway when stationary or at low speed. The inner hole of the support ring 83 has a milled-flat structure, which, during pitch change, cooperates with the milled-flat structure at the blade root to prevent rotation. A blade root adjusting shim 84 is also installed between the support ring 83 and the top of the corresponding blade sleeve 11. By grinding the thickness of the blade root adjusting shim 84, the two bearing balls 81 are thus kept in a tightly fitted state. The propeller root adjusting shim 84 is made of polytetrafluoroethylene material with low friction. The thickness of the propeller root adjusting shim 84 is ground and the gap between the propeller root adjusting shim 84 and the end face of the propeller sleeve is adjusted to ensure that the ball bearing is in a tight-fitting state and to prevent the bearing balls 81 from falling and getting stuck.

[0033] During operation, the propeller root and propeller hub 1 transmit centrifugal force, torque, and other loads through two rows of grease-lubricated angular contact ball bearings. The inner and outer slides of the bearing balls are integrated on the propeller sleeve and propeller root, respectively. During assembly, the bearing balls 81 are installed through the two rows of ball mounting holes 12 at the front end of the propeller sleeve, and the bearing balls 81 are fixed with a nylon retainer 82 with notches. The propeller root is supported by a split support ring 83 to keep the bearing balls 81 in a tight-fitting state. This structure allows the lower propeller blade 2 to be disassembled without disassembling the propeller hub 1, enabling the disassembly and replacement of the propeller blade 2 in the field (see the assembly and disassembly structure diagram). Figure 9 and Figure 10 (As shown).

[0034] A preferred embodiment of the present invention also provides an aircraft having an open rotor engine pitch-changing connection structure as described above. Therefore, when the aircraft of the present invention needs to disassemble the pitch-changing actuator for maintenance and replacement, it is only necessary to first loosen the connection between the pitch-changing actuator and the rotor hub 1, and then rotate the pitch-changing actuator so that the multiple lace grooves 302 correspond one-to-one with the multiple eccentric pins 21, as shown below. Figure 6-8 As shown in the diagram, the variable pitch actuator can be pulled out as a whole along the axial direction. This eliminates the need to disassemble the hub 1 and blade 2 simultaneously when disassembling the variable pitch actuator, simplifying the disassembly and assembly process and making it easier to replace the consumable parts inside the variable pitch actuator, thus greatly improving maintainability. At the same time, since the variable pitch actuator adopts a modular design as a whole, the structure is simple, easy to disassemble and assemble, and has low maintenance costs. It can also be assembled separately from the hub 1 and blade 2 to further improve assembly efficiency and has great potential for engineering applications. In addition, the mounting channel between blade 2 and blade sleeve 11 is detachable, so blade 2 can be disassembled without disassembling the hub 1, allowing for disassembly and replacement of blade 2 in the field.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A variable pitch connection structure for an open rotor engine, characterized in that, include: Hollow annular hub (1), multiple blades (2) and modularly designed into a single variable pitch actuator; The outer periphery of the propeller hub (1) has multiple propeller sleeves (11) that are evenly spaced in the circumference and extend radially respectively. The multiple propeller sleeves (11) correspond to multiple propeller blades (2) one by one, and each propeller sleeve (11) has an installation channel that connects to the cavity of the propeller hub (1) at the center of the propeller hub (1). Each blade (2) includes a blade body, blade root and eccentric pin (21) connected in sequence along the axial direction. The blade (2) is detachably installed in the mounting channel of the corresponding blade sleeve (11) through its blade root, and the eccentric pin (21) extends into the cavity of the blade hub (1). The variable pitch actuator is connected to the rotor hub (1) through the axial direction. It includes a dial (3) located in the cavity of the rotor hub (1). The outer periphery of the dial (3) is concave to form an annular U-shaped groove. The eccentric pins (21) of multiple rotor blades (2) are installed in the U-shaped groove. When the internal components of the variable pitch actuator slide along the axial direction, the rotor blades (2) are deflected by the friction between the U-shaped groove and the eccentric pins (21) to change the pitch. On the wall surface of one side of the U-shaped groove, there are multiple circumferentially spaced and connected lace grooves (302) corresponding to multiple eccentric pins (21). When the variable pitch actuator is rotated, the multiple lace grooves (302) correspond one-to-one with multiple eccentric pins (21) so that the variable pitch actuator can be pulled out as a whole along the axial direction.

2. The open rotor engine pitch-changing connection structure according to claim 1, characterized in that, The open rotor engine pitch connection structure also includes a paddle shaft support disc (4). The variable pitch actuator also includes a hydraulic cylinder (5), a piston (6), and an oil supply shaft assembly (7). The hydraulic cylinder (5) is connected to the front end face of the propeller hub (1), and the shift sleeve shaft support plate (4) is connected to the rear end face of the propeller hub (1). The oil supply shaft assembly (7) is axially inserted through the hydraulic cylinder (5) and the shift sleeve shaft support plate (4) for support. The piston (6) is mounted on the outer circle of the front end of the oil supply shaft assembly (7) and located in the oil cylinder (5) to divide the inner cavity of the oil cylinder (5) into a large-distance oil chamber and a small-distance oil chamber arranged in sequence along the axis. The oil supply shaft assembly (7) is provided with a first oil inlet channel and a second oil inlet channel that extend along the axis respectively. The first oil inlet channel is connected to the large-distance oil chamber and the second oil inlet channel is connected to the small-distance oil chamber. The dial (3) is mounted on the outer circle of the middle section of the oil supply shaft assembly (7).

3. The open rotor engine pitch-changing connection structure according to claim 2, characterized in that, The oil supply shaft assembly (7) includes a hollowed-out pry bar shaft (71) arranged axially, a locking nut (72), a connecting key (73), and a pry bar sleeve (74). The outer circle of the front end of the shift sleeve shaft (71) is machined with an external thread, and the outer circle of the middle section of the shift sleeve shaft (71) is machined with an outwardly protruding limiting step; The locking nut (72) and piston (6) are sequentially installed on the outer circle of the front end of the shift sleeve shaft (71), and the locking nut (72) is located at the front end of the piston (6). The connecting key (73) is installed between the piston (6) and the shift sleeve shaft (71). The shift sleeve (74) and the shift plate (3) are sequentially installed on the outer circle of the middle section of the shift shaft (71), and the shift sleeve (74) is located between the piston (6) and the shift plate (3). The shift plate (3) is axially limited against the limiting step, and the piston (6), the shift sleeve (74) and the shift plate (3) are fixed on the shift shaft (71) by the locking nut (72).

4. The open rotor engine pitch-changing connection structure according to claim 3, characterized in that, The oil supply shaft assembly (7) also includes an adjusting shim (75) mounted on the outer circle of the shift sleeve shaft (71). The adjusting shim (75) is located between the piston (6) and the shift sleeve (74) to adjust the feather angle position of the blade (2). The oil supply shaft assembly (7) also includes a hydraulic oil pipe (76) installed axially in the shift sleeve shaft (71) and an oil pipe support ring (77) for supporting the hydraulic oil pipe (76). The hydraulic oil pipe (76) has a first oil inlet channel and a second oil inlet channel. The oil pipe support ring (77) is installed on the outer circle of the rear end of the hydraulic oil pipe (76) and is tightly supported in the inner hole of the shift sleeve shaft (71).

5. The open rotor engine pitch-changing connection structure according to claim 2, characterized in that, The dial (3) includes a dial sleeve retainer (31) and a dial sleeve (32) which are sequentially mounted on the outer circle of the oil supply shaft assembly (7) along the axial direction, and a connecting pin (33) for fixing the two together. The derailleur retainer (31) is disc-shaped and is used to restrict the eccentric pin (21) of the blade (2) from passing through axially; The shift sleeve (32) includes a sleeve whose first end is connected to the shift sleeve retainer (31) via a connecting pin (33), and multiple lace pieces (322) fixedly connected to the outer circle of the second end of the sleeve. The multiple lace pieces (322) are evenly spaced along the circumference so that a lace groove (302) is formed between two adjacent lace pieces (322), and the gap between the lace pieces (322) and the shift sleeve retainer (31) also forms a U-shaped groove.

6. The open rotor engine pitch-changing connection structure according to claim 5, characterized in that, The oil supply shaft assembly (7) also includes multiple axially arranged guide rods (78). The multiple guide rods (78) are spaced apart along the circumference of the dial (3), and the front end of each guide rod (78) is fixedly connected to the oil cylinder (5). The rear end of each guide rod (78) is provided with a dial sleeve baffle (31).

7. The open rotor engine pitch-changing connection structure according to claim 1, characterized in that, Two bearing inner raceways are provided on the outer circle of the blade root of each blade (2) and are arranged in sequence along the axial direction and are concave in the circumference. Two bearing outer raceways are provided on the inner wall of the mounting channel of the blade sleeve (11). The outer wall of the paddle sleeve (11) is also provided with ball mounting holes (12) that connect the two outer raceways of the bearing respectively, and bearing plugs (13) for sealing the ball mounting holes (12). The outer bearing balls (81) enter the two raceway rings composed of the inner and outer raceways of the bearing through the ball mounting holes (12), and form two ball bearings with the cage (82) installed between the paddle root and the paddle sleeve (11).

8. The open rotor engine pitch-changing connection structure according to claim 7, characterized in that, Each paddle sleeve (11) is also equipped with a support ring (83) at its top. The outer circle of the paddle (2) is also convex to form a support step. The paddle (2) is supported on the support ring (83) by the support step. The paddle (2) is lifted up and supported on the support ring (83). The lifting of the paddle (2) causes the inner raceway of the two bearings to be lifted up and misaligned with the corresponding outer raceway of the bearings, thereby making the two bearing balls (81) in a tight fit. A blade root adjustment pad (84) is also installed between the top of the support ring (83) and the corresponding blade sleeve (11) so that the two rings of bearing balls (81) are in a tight fit by grinding the thickness of the blade root adjustment pad (84).

9. The open rotor engine pitch-changing connection structure according to claim 1, characterized in that, The rear wall of the propeller hub (1) is also provided with a mounting hole that connects to the cavity of its propeller hub (1), and a one-way exhaust valve (91) is installed in the mounting hole. Each blade (2) is also equipped with a counterweight arm (92) on its outer circle. The counterweight arm (92) is located outside the hub (1), and the cantilever end of the counterweight arm (92) is connected to a counterweight block (93). The oil cylinder (5) is also provided with an oil drain hole that connects to its inner cavity, and an oil drain valve (94) is installed in the oil drain hole.

10. An aircraft, characterized in that, It has an open rotor engine pitch connection structure as described in any one of claims 1-9.

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