Electric pitch changing mechanism for aircraft blades

Abstract

The invention belongs to the technical field of low-altitude flight, and provides an aircraft blade electric pitch changing mechanism which comprises a blade assembly, a propeller hub, a driving assembly and a propeller pitch control module, the blade assembly is connected with the propeller hub, and the propeller pitch control module is installed in the propeller hub. A sensor assembly used for collecting angle changes or distance changes of the propeller pitch control module in real time is installed on the propeller pitch control module, and the propeller blade assembly is connected with the propeller pitch control module, collects the angle changes or the distance changes of the propeller pitch control module through the sensor assembly, feeds back the angle changes or the distance changes in real time and controls changes of a propeller pitch angle. The sensor is adopted to collect the rotation angle of the lead screw shaft, collect the displacement of the variable-pitch sliding block and directly collect the pitch angle, the variable-pitch angle can be fed back and controlled in real time, the structure is simple, stepless control over the variable-pitch angle can be achieved, the adjusting gasket is used for adjusting the gap of the lead screw shaft in the propeller hub, and the adjustment precision is high. And the response speed of the screw rod shaft and the response precision of the pitch angle of the paddle are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of low-altitude flight, and in particular relates to an electric pitch-changing mechanism for aircraft blades. Background Art

[0002] Aircraft propellers are a key component in aviation propulsion systems, generating thrust or pull by rotating to drive the aircraft forward. According to their design features and application scenarios, propellers can be divided into different types, such as fixed-pitch propellers, variable-pitch propellers, and reversible-pitch propellers. With the development of the aviation industry, the demand for high-performance and high-efficiency propeller systems is increasing. In various applications, variable-pitch propellers have become one of the key components because they can automatically adjust the blade angle according to flight conditions, thereby optimizing aerodynamic performance and cruising range. The variable pitch function is achieved by changing the angle between the propeller blades and the rotation axis, allowing the propeller to provide optimal thrust or pull in different flight phases. In addition to traditional fixed-wing aircraft and helicopters, variable-pitch propellers also have broad application prospects in the emerging fields of eVTOL (electric vertical take-off and landing) aircraft and long-endurance drones. These new aircraft require efficient transitions between different flight modes (such as vertical takeoff / landing and cruise flight), placing higher demands on the propeller's versatility and flexibility. Traditional propellers achieve pitch adjustment by adding a responsive mechanical stop to the pitch slider, which stops the slider from moving when it reaches the desired limit. However, this solution cannot monitor the propeller pitch angle in real time and can only be fixed at a few preset positions. It cannot be set to a different position at any time, which affects the aerodynamic efficiency of the propulsion system. Currently, the positional accuracy of the lead screw shaft in the pitch mechanism is primarily guaranteed by the machining accuracy of the bearing locating features, or by adjusting the bearing locating features based on their assembly. This introduces certain machining errors, which reduces the response speed and accuracy of the pitch mechanism. Clearances between gears within the drive assembly and between the lead screw and nut create a gap. The accumulated backlash in the transmission path from the motor output to the drive assembly output shaft reduces the load response accuracy and speed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an aircraft blade electric pitch change mechanism with a simple structure, real-time feedback and real-time control of pitch angle, and improved response speed and response accuracy of blade pitch angle.

[0004] The technical solution adopted by the present invention to solve the above-mentioned technical problems is: an aircraft blade electric pitch change mechanism, characterized in that it includes a blade assembly, a hub, a drive assembly and a pitch control module, the blade assembly is connected and installed with the hub, the pitch control module is installed in the hub, and the pitch control module is installed with a sensor assembly for real-time acquisition of angle changes or distance changes of the pitch control module. The blade assembly is connected to the pitch control module and acquires angle changes or distance changes of the pitch control module through the sensor assembly, and provides real-time feedback and controls the change of the pitch angle.

[0005] In the above-mentioned electric pitch change mechanism of an aircraft blade, the pitch control module includes a screw shaft, a screw nut and a pitch change slider. The square hole at the bottom of the output shaft of the drive assembly forms a wedge-shaped fit with the square shaft at the top of the screw shaft and transmits the driving torque to the screw shaft. The screw nut and the screw shaft are matched through threads. As the screw shaft rotates, the screw nut can slide up and down in the axial direction. The pitch change slider and the screw nut are connected by bolts. When working, the pitch change slider and the screw nut slide up and down together along the axial direction under the drive of the screw nut.

[0006] In the above-mentioned aircraft blade electric pitch change mechanism, the pitch control module also includes an upper angular contact bearing, a lower angular contact bearing and an upper cover plate. The upper angular contact bearing and the lower angular contact bearing are respectively matched with the upper and lower step surfaces of the screw shaft. The upper angular contact bearing is installed in the lower inner hole groove of the upper cover plate, and the lower angular contact bearing is installed in the lower mounting groove of the hub. The upper cover plate is connected to the top of the hub by bolts.

[0007] As a further optimization, in the above-mentioned aircraft integrated blade electric pitch control structure, an adjusting washer is installed between the upper angular contact bearing and the upper cover plate.

[0008] In the above-mentioned electric pitch-changing mechanism for aircraft blades, needle roller bearings, thrust needle roller bearings, and blade mounting nuts are further provided between the blade assembly and the hub. The three blade assembly groups, through the needle roller bearings, respectively engage with the stepped surfaces within three holes evenly distributed on the side of the hub. The blade mounting nut, through the thrust needle roller bearing, engages with the stepped surface in the middle of the blade assembly and is threadedly connected to the holes evenly distributed on the side of the hub, locking the blade assembly to the hub. This allows the blade assembly to rotate around the blade root axis within the hub hole while simultaneously transmitting the blade's all-directional loads to the hub.

[0009] In the aforementioned aircraft blade electric pitch control mechanism, a wear ring is positioned between the blade mounting nut and the blade assembly, and is retained within the inner groove of the blade mounting nut. This transmits the blade root bending moment through the wear ring and needle roller bearing, resulting in a more balanced force distribution than with existing methods using a single needle roller bearing, optimizing the force distribution between the blade root and the hub.

[0010] As a further optimization, in the above-mentioned aircraft integrated blade electric pitch control structure, the blade assembly is connected to the pitch slider through an eccentric slot. When the pitch slider slides up and down, the blade assembly will also rotate along its own axis and realize the change of the pitch angle.

[0011] As a further optimization, in the above-mentioned aircraft integrated blade electric pitch control structure, a pitch block is provided on the blade assembly, and the pitch block on the blade assembly is installed in a groove on the side of the pitch slider. The three blocks are respectively fixed to the top of the hub side hole by bolts to prevent the blade mounting nut from loosening.

[0012] As one approach, as an optimization, in the aforementioned aircraft integrated propeller blade electric pitch control structure, the sensor assembly includes a sensor and a sensor connector. The sensor connector is connected to the sensor's rotating shaft through a surface fit. The sensor connector cooperates with the groove at the bottom of the screw shaft to provide real-time feedback on the angular position of the screw shaft. Here, the screw nut connected to the screw directly drives the pitch slider on the propeller hub. The sensor collects the screw angle to control the stroke accuracy and response speed, which is more direct and accurate than collecting data from the motor end.

[0013] As a second method, as an optimization, in the above-mentioned aircraft integrated blade electric pitch control structure, the sensor assembly includes a sensor and a sensor connector, and the sensor connector is in contact with the pitch slider, wherein the sensor is a position sensor and is used to collect the displacement of the pitch slider after being driven by the screw shaft and the screw nut. The sensor feeds back the collected displacement value of the pitch slider to the drive assembly, and the drive assembly adjusts the movement of the screw shaft through the output shaft according to the feedback value and forms a control feedback loop.

[0014] As a third method, as an optimization, in the above-mentioned aircraft integrated blade electric pitch control structure, the sensor assembly includes a sensor, wherein the sensor is an angle sensor, and the sensor is arranged at the end of the blade assembly and collects the pitch angle of the blade assembly.

[0015] Compared with the prior art, the advantages of the present invention are:

[0016] 1. Three data acquisition methods can be used: sensors are used to collect the rotation angle of the screw shaft, the displacement of the pitch slider, and the pitch angle directly. This allows for real-time feedback and control of the pitch angle. The structure is simple, enabling stepless control of the pitch angle. Furthermore, the angle feedback improves control accuracy and response speed.

[0017] 2. The pitch control module is arranged together with the drive assembly it controls, realizing integrated control and drive, simplifying the signal transmission structure, and improving signal quality and pitch-changing performance.

[0018] 3. The combination of the screw end sensor and the motor's internal position sensor (Hall magnetic ring or magnetic encoder) can monitor faults in the transmission route in real time and make corresponding strategies in time;

[0019] 4. An adjusting washer is added to adjust the clearance between the screw shaft and the propeller hub, which improves the response speed of the screw shaft and the response accuracy of the blade pitch angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of a first embodiment of the integrated electric pitch control structure of the aircraft;

[0021] Figure 2 This is a schematic diagram of a second embodiment of the integrated electric pitch control structure of the aircraft;

[0022] Figure 3 This is a schematic diagram of the third embodiment of the integrated electric pitch control structure of the aircraft;

[0023] Figure 4 It is a three-dimensional diagram of the pitch-changing mechanism of the blade assembly. DETAILED DESCRIPTION

[0024] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0025] In the figure, the blade assembly 100; the hub 200; the drive assembly 300; the pitch control module 400; the screw shaft 401; the screw nut 402; the pitch slider 403; the upper angular contact bearing 404; the lower angular contact bearing 405; the upper cover plate 406; the adjusting washer 500; the needle roller bearing 600; the thrust needle roller bearing 700; the blade mounting nut 800; the pitch block 900; the wear-resistant ring 1000; the sensor assembly 1001; the sensor 1002; and the sensor connector 1003.

[0026] Example 1

[0027] like Figure 1 and Figure 4As shown, the electric pitch-changing mechanism of the aircraft blade includes a blade assembly 100, a hub 200, a drive assembly 300 and a pitch control module 400. The blade assembly 100 is connected to the hub 200 and installed. The pitch control module 400 is installed in the hub 200. The pitch control module 400 is equipped with a sensor assembly 1001 for real-time acquisition of angle changes or distance changes of the pitch control module 400. The blade assembly 100 is connected to the pitch control module 400 and acquires angle changes or distance changes of the pitch control module 400 through the sensor assembly 1001, provides real-time feedback and controls the change of the pitch angle. Here, the drive assembly 300 can be responsible for the motor to drive the motor to rotate according to the received motor control instructions.

[0028] Specifically, the pitch control module 400 includes a screw shaft 401, a screw nut 402 and a pitch-changing slider 403. The square hole at the bottom of the output shaft of the drive assembly 300 forms a wedge-shaped fit with the square shaft at the top of the screw shaft 401 and transmits the driving torque to the screw shaft 401. The screw nut 402 and the screw shaft 401 are matched through threads. As the screw shaft 401 rotates, the screw nut 402 can slide up and down in the axial direction. The pitch-changing slider 403 and the screw nut 402 are connected by bolts. When working, the pitch-changing slider 403 and the screw nut 402 slide up and down along the axial direction together under the drive of the screw nut 402; the pitch control module 400 also It includes an upper angular contact bearing 404, a lower angular contact bearing 405 and an upper cover plate 406. The upper angular contact bearing 404 and the lower angular contact bearing 405 respectively cooperate with the upper and lower step surfaces of the screw shaft 401, so as to mainly bear the axial load and positioning function. The upper angular contact bearing 404 is installed in the lower inner hole groove of the upper cover plate 406, and the lower angular contact bearing 405 is installed in the lower mounting groove of the hub 200. The upper cover plate 406 is connected to the top of the hub 200 by bolts. An adjusting washer 500 is installed between the upper angular contact bearing 404 and the upper cover plate 406. Here, the adjusting washer 500 is mainly used to adjust the axial position of the screw shaft 401.

[0029] As a further optimization, in order to optimize the force on the propeller root and the hub 200, a needle roller bearing 600, a thrust needle roller bearing 700 and a blade mounting nut 800 are further provided between the blade assembly 100 and the hub 200, wherein the three groups of blade assemblies 100 are respectively matched with the step surfaces in the three holes evenly distributed on the side of the hub 200 through the needle roller bearings 600, and the blade mounting nut 800 is matched with the middle step surface of the blade assembly 100 through the thrust needle roller bearing 700, and is connected to the holes evenly distributed on the side of the hub 200 through threads and locks the blade assembly 100 and the hub 200, and a pitch block 900 is provided on the blade assembly 100, and the pitch block on the blade assembly 100 900 is installed in the groove on the side of the pitch-changing slider 403. The three blocks are respectively fixed to the top of the side hole of the hub 200 by bolts and prevent the blade mounting nut 800 from loosening. In this way, the blade assembly 100 can rotate around the axis of the blade root in the hole of the hub 200, while transmitting the isotropic load of the blade to the hub 200. There is a block fixed by bolts on the top of the side hole of the hub 200 to prevent the blade mounting nut 800 from loosening. The blade assembly 100 is connected to the pitch-changing slider 403 through an eccentric slot. When the pitch-changing slider 403 slides up and down, the blade assembly 100 will also rotate along its own axis and realize the change of the pitch angle.

[0030] In addition, as a further optimization, a wear-resistant ring 1000 is provided between the blade mounting nut 800 and the blade assembly 100. The wear-resistant ring 1000 is stuck in the inner groove of the blade mounting nut 800. In this way, the bending moment of the blade root is transmitted through the wear-resistant ring 1000 and the needle bearing 600. Compared with the existing force transmission method of a single needle bearing, the force is more balanced, and the force conditions of the blade root and the hub 200 are optimized.

[0031] In order to achieve variable pitch control, the square hole at the bottom of the rotating shaft of the drive assembly 300 forms a wedge-shaped fit with the square shaft at the top of the screw shaft 401, transmitting the driving torque to the screw shaft 401; the circumference of the drive assembly 300 is connected to the upper cover plate 406 by bolts, which is used to fix the position of the drive assembly 300. The sensor component 1001 in this embodiment includes a sensor 1002 and a sensor connector 1003. The sensor connector 1003 is connected to the rotating shaft of the sensor 1002 by a surface fit. The sensor connector 1003 cooperates with the groove at the bottom of the screw shaft 401 to provide real-time feedback on the angular position of the screw shaft 401. Here, the screw nut 402 connected to the screw directly drives the variable pitch slider 403 on the hub 200. The sensor 1002 collects the screw angle to control the stroke accuracy and reaction speed, which is more direct and accurate than collecting the motor end. A motor sensor can also be installed on the motor. The motor sensor here can be a combination of a Hall magnetic ring or a magnetic encoder. The redundant feedback design of the dual sensors inside the motor and at the lead screw end is characterized by high reliability. It can detect faults in the transmission route of the drive assembly 300 and make corresponding strategies in time to stabilize the fuselage posture and ensure safety. When one of the sensors fails and loses the signal, the other sensor can take over the signal in time to ensure that the system does not get out of control.

[0032] During installation, first fix the variable pitch slider 403 and the screw nut 402 with several bolts. Through threaded fit, screw the screw nut 402 to the middle of the screw shaft 401. Install the upper angular contact bearing 404 and the lower angular contact bearing 405 on the upper and lower step surfaces of the screw shaft 401 respectively; install the upper angular contact bearing 404 together with the adjusting washer 500 into the inner hole groove under the upper cover plate 406, and the outer ring of the upper angular contact bearing 404 is supported against the upper cover plate 406 through the adjusting washer 500. Inner hole groove; Assemble the lower angular contact bearing 405 together with the screw shaft 401 and other assembled parts into the vertical hole of the hub 200, the outer ring of the lower angular contact bearing 405 is against the bearing mounting groove of the lower part of the hub 200, and the upper cover plate 406 is fastened to the upper part of the hub 200 by bolts. If the gap between the upper cover plate 406 and the hub 200 or the rotation of the screw shaft 401 after assembly does not meet the relevant design requirements, adjust it by adjusting the thickness of the adjusting washer 500 to achieve the desired effect. In accordance with the design requirements, the three sets of blade assemblies 100 are respectively installed on the stepped surfaces of the three holes evenly distributed on the side of the hub 200 through three sets of needle bearings 600; the blade mounting nut 800 is positioned and matched with the thrust needle bearing 700 and the stepped surface in the middle of the blade assembly 100, and the internal thread of the hole evenly distributed on the side of the hub 200, so as to fix and lock the blade assembly 100 and the hub 200, and the pitch block 900 on the blade assembly 100 is installed in the groove on the side of the pitch slider 403; three The stoppers are fixed to the top of the side holes of the hub 200 by bolts to prevent the blade mounting nuts 800 from loosening; the square hole at the bottom of the rotating shaft of the drive assembly 300 forms a wedge-shaped fit with the square shaft at the top of the screw shaft 401, and the circumference of the drive assembly 300 is connected to the upper cover plate 406 by bolts to fix the position of the drive assembly 300; the sensor connector 1003 and the rotating shaft of the sensor 1002 are matched by surface, and the sensor connector 1003 and the groove at the bottom of the screw shaft 401 cooperate with each other.

[0033] Example 2

[0034] like Figure 2 As shown, most of the structures of this embodiment are the same as those of the first embodiment, except that the sensor assembly 1001 includes a sensor 1002 and a sensor connector 1003, and the sensor connector 1003 is in contact with the variable pitch slider 403. The sensor 1002 is a position sensor and is used to collect the displacement of the variable pitch slider 403 after being transmitted by the lead screw shaft 401 and the lead screw nut 402. The sensor 1002 feeds back the collected displacement value of the variable pitch slider 403 to the drive assembly 300, and the drive assembly 300 adjusts the movement of the lead screw shaft 401 through the output shaft according to the feedback value and forms a control feedback loop.

[0035] When the internal transmission gear of the drive assembly 300 fails and suddenly stalls, the sensor 1002 detects a sudden change in the displacement value of the pitch slider 403 that does not match the value calculated by the ECU. At this point, the motor speed feedback from the motor-end speed sensor 1002 within the drive assembly 300 can be compared. If the motor speed difference is not significant, it can be determined that the internal transmission gear of the drive assembly 300 has failed, possibly due to wear, fracture, or deformation. If the motor speed also changes significantly, it may be a fault in the drive software or motor. The system can adjust the propeller speed and pitch angle based on the cause of the fault, stabilizing the fuselage posture and facilitating subsequent safety measures. Compared to the first embodiment, where the sensor 1002 collects the rotation angle of the screw shaft 401, the second embodiment directly collects the displacement of the pitch slider 403 after transmission through the screw shaft 401 and the screw nut 402. Its feedback is more direct, efficient, and accurate, but the layout and structural design are more complex.

[0036] Example 3

[0037] like Figure 3 As shown, most of the structures of this embodiment are the same as those of the first embodiment, except that the sensor assembly 1001 includes a sensor, wherein the sensor 1002 is an angle sensor, and the sensor 1002 is arranged at the end of the blade assembly 100 and collects the pitch angle of the blade assembly 100. Here, relative to the first embodiment, the sensor 1002 collects the rotation angle of the screw shaft 401, the second embodiment collects the displacement of the pitch slider 403, and the third embodiment collects the pitch angle of the blade assembly 100, and directly feeds back the final control target. The feedback is most efficient and has the highest accuracy, but the space here is small, and the parts arrangement and structural design are the most complex.

[0038] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications to the described specific embodiments or replace them with similar methods without departing from the scope defined by the spirit of the present invention.

Claims

1. An aircraft blade electric pitch change mechanism, characterized in that: It includes a blade assembly, a hub, a drive assembly and a pitch control module. The blade assembly is connected to the hub and installed. The pitch control module is installed in the hub. The pitch control module is equipped with a sensor assembly for real-time acquisition of angle changes or distance changes of the pitch control module. The blade assembly is connected to the pitch control module and acquires angle changes or distance changes of the pitch control module through the sensor assembly, which provides real-time feedback and controls the change of the pitch angle.

2. The electric pitch-changing mechanism for aircraft blades according to claim 1, characterized in that: The pitch control module includes a screw shaft, a screw nut and a pitch-changing slider. The square hole at the bottom of the output shaft of the drive assembly forms a wedge-shaped fit with the square shaft at the top of the screw shaft and transmits the driving torque to the screw shaft. The screw nut and the screw shaft are matched through threads. As the screw shaft rotates, the screw nut can slide up and down in the axial direction. The pitch-changing slider and the screw nut are connected by bolts. When working, the pitch-changing slider and the screw nut slide up and down together along the axial direction under the drive of the screw nut.

3. The electric pitch-changing mechanism for aircraft blades according to claim 1 or 2, characterized in that: The pitch control module also includes an upper angular contact bearing, a lower angular contact bearing and an upper cover plate. The upper angular contact bearing and the lower angular contact bearing respectively cooperate with the upper and lower step surfaces of the screw shaft. The upper angular contact bearing is installed in the lower inner hole groove of the upper cover plate, and the lower angular contact bearing is installed in the lower mounting groove of the hub. The upper cover plate is connected to the top of the hub by bolts.

4. The aircraft blade electric pitch change mechanism according to claim 1 or 2, characterized in that: Needle roller bearings, thrust needle roller bearings and blade mounting nuts are also provided between the blade assembly and the hub, wherein the three groups of blade assemblies are respectively matched with the step surfaces in the three holes evenly distributed on the side of the hub through the needle roller bearings; the blade mounting nut is matched with the middle step surface of the blade assembly through the thrust needle roller bearing, and is threadedly connected to the holes evenly distributed on the side of the hub to lock the blade assembly and the hub.

5. The aircraft blade electric pitch change mechanism according to claim 4, characterized in that: A wear-resistant ring is provided between the blade mounting nut and the blade assembly, and the wear-resistant ring is clamped in the inner groove of the blade mounting nut.

6. The aircraft blade electric pitch change mechanism according to claim 4, characterized in that: The blade assembly is connected to the pitch-changing slider via an eccentric slot. When the pitch-changing slider slides up and down, the blade assembly also rotates along its own axis and changes the pitch angle.

7. The aircraft blade electric pitch change mechanism according to claim 1, characterized in that: The blade assembly is provided with a pitch block, which is installed in the groove on the side of the pitch slider. The three blocks are fixed to the top of the hub side hole by bolts to prevent the blade mounting nut from loosening.

8. The aircraft blade electric pitch change mechanism according to claim 2, characterized in that: The sensor assembly includes a sensor and a sensor connector. The sensor connector is connected to the rotating shaft of the sensor through a surface fit. The sensor connector cooperates with the groove at the bottom of the screw shaft to provide real-time feedback on the angular position of the screw shaft.

9. The aircraft blade electric pitch change mechanism according to claim 2, characterized in that: The sensor assembly includes a sensor and a sensor connector. The sensor connector contacts and cooperates with the variable pitch slider. The sensor is a position sensor and is used to collect the displacement of the variable pitch slider after being driven by the screw shaft and the screw nut. The sensor feeds back the collected displacement value of the variable pitch slider to the drive assembly. The drive assembly adjusts the movement of the screw shaft through the output shaft according to the feedback value and forms a control feedback loop.

10. The aircraft blade electric pitch change mechanism according to claim 2, characterized in that: The sensor assembly includes a sensor, wherein the sensor is an angle sensor, and the sensor is arranged at the end of the blade assembly and collects the pitch angle of the blade assembly.

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