An aircraft blade electric variable pitch mechanism

Abstract

This utility model belongs to the field of low-altitude flight technology and provides an electric pitch control mechanism for aircraft propellers. It includes a propeller assembly, a propeller hub, a drive assembly, and a pitch control module. The propeller assembly is connected to the propeller hub, and the pitch control module is installed inside the hub. A sensor assembly is mounted on the pitch control module to collect real-time changes in the propeller's angle or distance. The propeller assembly is connected to the pitch control module and uses the sensor assembly to collect and provide real-time feedback on these changes, thereby controlling the pitch angle. This patent uses sensors to collect the rotation angle of the lead screw shaft, the displacement of the pitch slider, and directly collect the pitch angle, enabling real-time feedback and control of the pitch angle. Its structure is simple, and it achieves stepless control of the pitch angle. Adjusting washers are used to adjust the clearance of the lead screw shaft within the propeller hub, improving the response speed of the lead screw shaft and the response accuracy of the propeller's pitch angle.

Description

Technical Field

[0001] This utility model belongs to the field of low-altitude flight technology, specifically relating to an electric pitch control mechanism for aircraft propeller blades. Background Technology

[0002] Aircraft propellers are a key component of aviation propulsion systems, generating thrust or pull through rotation to propel aircraft forward. Based on their design characteristics and application scenarios, propellers can be categorized into different types, including fixed-pitch propellers, variable-pitch propellers, and reversible-pitch propellers. With the development of the aviation industry, the demand for high-performance, high-efficiency propeller systems is increasing. In various applications, variable-pitch propellers have become a key component because they can automatically adjust the blade angle according to flight conditions, thereby optimizing aerodynamic performance and 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 at different stages of flight. Besides traditional fixed-wing aircraft and helicopters, variable-pitch propellers also have broad application prospects in emerging eVTOL (electric vertical takeoff and landing) aircraft and long-endurance unmanned aerial vehicles (UAVs). These new aircraft need to efficiently switch between different flight modes (such as vertical takeoff / landing, cruise flight, etc.), thus placing higher demands on the versatility and flexibility of propellers. Traditional propellers adjust the pitch angle by adding a responsive mechanical limit device to the pitch slider, causing the slider to stop moving after reaching a certain limit. However, this solution cannot monitor the blade pitch angle in real time, and the pitch angle can only be fixed at a few preset positions. If the pitch angle cannot be fixed at other positions, it will affect the aerodynamic efficiency of the propulsion system. Currently, the positional accuracy of the lead screw shaft in the blade pitch mechanism is mainly guaranteed by the machining accuracy of the bearing positioning features, or by adjusting the assembly features of the bearing positioning features. There is a certain machining error, which reduces the response speed and accuracy of the pitch mechanism. There are clearances between the gears and between the lead screw and nut inside the drive assembly. The accumulated backlash in the transmission path from the motor output end to the drive assembly output shaft will reduce the response accuracy and speed to the load. Utility Model Content

[0003] The technical problem this invention aims to solve is to provide an aircraft rotor blade electric pitch control mechanism that is simple in structure, provides real-time feedback and control of the pitch angle, and improves the response speed and accuracy of the rotor blade pitch angle, addressing the limitations of existing technologies.

[0004] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: an electric pitch control mechanism for aircraft propellers, characterized in that it includes a propeller assembly, a propeller hub, a drive assembly, and a pitch control module. The propeller assembly is connected and installed to the propeller hub, and the pitch control module is installed in the propeller hub. The pitch control module is equipped with a sensor assembly for real-time acquisition of changes in the angle or distance of the pitch control module. The propeller assembly is connected to the pitch control module and collects changes in the angle or distance of the pitch control module through the sensor assembly, providing real-time feedback and controlling the change of the pitch angle.

[0005] In the aforementioned electric pitch control mechanism for aircraft propeller blades, the pitch control module includes a lead screw shaft, a lead screw nut, and a pitch slider. The square hole at the bottom of the output shaft of the drive assembly forms a wedge fit with the square shaft at the top of the lead screw shaft and transmits the driving torque to the lead screw shaft. The lead screw nut is threaded to the lead screw shaft, and can slide up and down axially as the lead screw shaft rotates. The pitch slider is bolted to the lead screw nut, and during operation, the pitch slider and the lead screw nut slide up and down together along the axial direction under the drive of the lead screw nut.

[0006] In the aforementioned aircraft propeller electric pitch control mechanism, the pitch control module further includes an upper angular contact bearing, a lower angular contact bearing, and an upper cover plate. The upper and lower angular contact bearings respectively mate with the upper and lower stepped surfaces of the lead 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 mounting groove at the lower part of the propeller hub. The upper cover plate is connected to the top of the propeller hub by bolts.

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

[0008] In the aforementioned electric pitch control mechanism for aircraft rotor blades, needle roller bearings, thrust needle roller bearings, and blade mounting nuts are also provided between the blade assembly and the rotor hub. Three sets of blade assemblies respectively engage with the stepped surfaces within three evenly distributed holes on the side of the rotor hub via needle roller bearings. The blade mounting nuts engage with the stepped surface in the middle of the blade assembly via thrust needle roller bearings and are threadedly connected to the evenly distributed holes on the side of the rotor hub, thus locking the blade assembly to the rotor hub. This allows the blade assembly to rotate around the blade root axis within the rotor hub holes, while simultaneously transmitting all-directional loads from the blades to the rotor hub.

[0009] In the aforementioned electric pitch control mechanism for aircraft rotor blades, a wear-resistant ring is provided between the rotor blade mounting nut and the rotor blade assembly, and the wear-resistant ring is engaged in the inner groove of the rotor blade mounting nut. This method, by transmitting the rotor blade root bending moment through the wear-resistant ring and the needle roller bearing, provides a more balanced force distribution compared to the existing method using a single needle roller bearing, thus optimizing the force distribution at the rotor blade root and rotor hub.

[0010] As a further optimization, in the above-mentioned integrated electric pitch control structure for aircraft propellers, the propeller assembly and the pitch slider are connected by an eccentric slot. When the pitch slider slides up and down, the propeller assembly will also rotate along its own axis and change the pitch angle.

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

[0012] As one approach, and as an optimization, in the aforementioned integrated electric pitch control structure for aircraft propellers, the sensor assembly includes a sensor and a sensor connector. The sensor connector is connected to the sensor's rotating shaft via a form-fitting connection. The sensor connector also engages with the groove at the bottom of the lead screw shaft, providing real-time feedback on the angular position of the lead screw shaft. Here, the lead screw nut directly drives the pitch slider on the propeller hub. Controlling the stroke accuracy and response speed by acquiring the lead screw rotation angle through the sensor is more direct and precise than acquiring it from the motor end.

[0013] As a second approach and an optimization, in the aforementioned integrated aircraft rotor electric pitch control structure, the sensor assembly includes a sensor and a sensor connector. The sensor connector contacts and engages with the pitch slider. The sensor is a position sensor used to collect the displacement of the pitch slider after being driven by the lead screw shaft and lead screw nut. The sensor feeds back the collected pitch slider displacement value to the drive assembly. The drive assembly adjusts the movement of the lead screw shaft through the output shaft based on the feedback value, thus forming a control feedback loop.

[0014] As a third approach and an optimization, in the aforementioned integrated aircraft rotor 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 rotor assembly to collect the pitch angle of the rotor assembly.

[0015] Compared with the prior art, the advantages of this utility model are:

[0016] 1. Three acquisition methods can be used: sensor acquisition of lead screw shaft rotation angle, acquisition of variable pitch slider displacement, and direct acquisition of pitch angle. Real-time feedback and real-time control of variable pitch angle are possible. Its structure is simple and can realize stepless control of variable pitch angle. Moreover, through angle feedback, the control accuracy and response speed are improved.

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

[0018] 3. The combination of the lead screw end sensor and the motor's built-in position sensor (Hall magnetic ring or magnetic encoder) can monitor faults in the transmission path in real time and take corresponding measures in a timely manner.

[0019] 4. An adjusting washer was added to adjust the clearance of the lead screw shaft in the propeller hub, which improves the response speed of the lead screw shaft and the response accuracy of the propeller blade pitch angle. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an embodiment of the integrated rotor blade electric pitch control structure for this aircraft.

[0021] Figure 2 This is a schematic diagram of Embodiment 2 of the integrated rotor electric pitch control structure for this aircraft;

[0022] Figure 3 This is a schematic diagram of Embodiment 3 of the integrated rotor blade electric pitch control structure for this aircraft;

[0023] Figure 4 This is a 3D view of the pitch-changing mechanism of the blade assembly. Detailed Implementation

[0024] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

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

[0026] Example 1

[0027] like Figure 1 and Figure 4As shown, the electric pitch control mechanism of this aircraft includes a blade assembly 100, a hub 200, a drive assembly 300, and a pitch control module 400. The blade assembly 100 is connected and installed to the hub 200. The pitch control module 400 is installed inside the hub 200. A sensor assembly 1001 is installed on the pitch control module 400 to collect real-time changes in the angle or distance of the pitch control module 400. The blade assembly 100 is connected to the pitch control module 400 and collects real-time feedback on changes in the angle or distance of the pitch control module 400 through the sensor assembly 1001, thereby controlling the change in the pitch angle. Here, the drive assembly 300 can be responsible for the motor and drive the motor to rotate according to the received motor control commands.

[0028] Specifically, the pitch control module 400 includes a lead screw shaft 401, a lead screw nut 402, and a pitch slider 403. The bottom square hole of the output shaft of the drive assembly 300 forms a wedge fit with the top square shaft of the lead screw shaft 401, transmitting the driving torque to the lead screw shaft 401. The lead screw nut 402 is threaded to the lead screw shaft 401, allowing it to slide axially up and down as the lead screw shaft 401 rotates. The pitch slider 403 is bolted to the lead screw nut 402, and during operation, it slides up and down along the axial direction together with the lead screw nut 402 under the drive of the lead 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 mate with the upper and lower stepped surfaces of the lead screw shaft 401, which is mainly used to bear axial load and for positioning. 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 mounting groove at the lower part of the propeller hub 200. The upper cover plate 406 is connected to the top of the propeller hub 200 by bolts. An adjusting washer 500 is installed between the upper angular contact bearing 404 and the upper cover plate 406. The adjusting washer 500 is mainly used to adjust the axial position of the lead screw shaft 401.

[0029] As a further optimization, to optimize the force distribution between the blade root and the blade hub 200, needle roller bearings 600, thrust needle roller bearings 700, and blade mounting nuts 800 are provided between the blade assembly 100 and the blade hub 200. The three sets of blade assemblies 100 respectively engage with the stepped surfaces of three evenly distributed holes on the side of the blade hub 200 via the needle roller bearings 600. The blade mounting nuts 800 engage with the stepped surface in the middle of the blade assembly 100 via the thrust needle roller bearings 700, and are threadedly connected to the evenly distributed holes on the side of the blade hub 200 to lock the blade assembly 100 to the blade hub 200. A pitch block 900 is provided on the blade assembly 100. The blade assembly 100 is installed in the groove on the side of the pitch slider 403. Three stops are fixed to the top of the side hole of the hub 200 by bolts to prevent the blade mounting nut 800 from loosening. This allows the blade assembly 100 to rotate around the root axis of the blade in the hole of the hub 200, while also transmitting the loads of the blade in all directions to the hub 200. The top of the side hole of the hub 200 has stops fixed by bolts to prevent the blade mounting nut 800 from loosening. The blade assembly 100 and the pitch slider 403 are connected by an eccentric slot. When the pitch slider 403 slides up and down, the blade assembly 100 will also rotate along its own axis and change 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 at the blade root is transmitted through the wear-resistant ring 1000 and the needle roller bearing 600. Compared with the existing force transmission method of a single needle roller bearing, the force is more balanced, and the force situation at the blade root and the hub 200 is optimized.

[0031] To achieve variable pitch control, the square hole at the bottom of the rotating shaft of the drive assembly 300 forms a wedge fit with the square shaft at the top of the lead screw shaft 401, transmitting the driving torque to the lead screw shaft 401. The drive assembly 300 is bolted to the upper cover plate 406 to fix its position. In this embodiment, the sensor assembly 1001 includes a sensor 1002 and a sensor connector 1003. The sensor connector 1003 is connected to the rotating shaft of the sensor 1002 through a form-fit connection. The sensor connector 1003 and the bottom groove of the lead screw shaft 401 cooperate to provide real-time feedback on the angular position of the lead screw shaft 401. Here, the lead screw nut 402 connected to the lead screw directly drives the variable pitch slider 403 on the propeller hub 200. Using the sensor 1002 to collect the lead screw rotation angle to control the stroke accuracy and response speed is more direct and precise than collecting data from the motor end. A motor sensor can also be installed on the motor. Here, the motor sensor can be a combination of Hall effect magnetic rings or magnetic encoders. This redundant feedback design with dual sensors inside the motor and at the lead screw end is characterized by high reliability. It can detect faults in the 300 transmission route of the drive assembly and take corresponding measures in time to stabilize the body posture and ensure safety. When one sensor fails and loses signal, the other sensor can take over the signal in time to ensure that the system does not go out of control.

[0032] During installation, first connect and fix the variable pitch slider 403 to the lead screw nut 402 with several bolts. Then, screw the lead screw nut 402 to the middle of the lead screw shaft 401 via threaded connection. Install the upper angular contact bearing 404 and the lower angular contact bearing 405 on the upper and lower stepped surfaces of the lead screw shaft 401, respectively. Install the upper angular contact bearing 404, along with the adjusting washer 500, into the lower inner groove of the upper cover plate 406. The outer ring of the upper angular contact bearing 404 is held against the upper cover plate 406 by the adjusting washer 500. The inner groove; the lower angular contact bearing 405, together with the lead screw shaft 401 and other assembled parts, is assembled into the vertical hole of the propeller hub 200. The outer ring of the lower angular contact bearing 405 abuts against the bearing mounting groove at the bottom of the propeller hub 200. The upper cover plate 406 is locked to the upper part of the propeller hub 200 with bolts. If the gap between the upper cover plate 406 and the propeller hub 200 or the rotation of the lead screw shaft 401 after assembly does not meet the relevant design requirements, the thickness of the adjusting washer 500 is adjusted to achieve the desired result. According to the design requirements, three sets of blade assemblies 100 are respectively installed onto the stepped surfaces of three evenly distributed holes on the side of the blade hub 200 via three sets of needle roller bearings 600; the blade mounting nuts 800, through the positioning fit between the thrust needle roller bearing 700 and the stepped surface in the middle of the blade assembly 100, and the internal threads of the evenly distributed holes on the side of the blade hub 200, fix and lock the blade assembly 100 to the blade hub 200; the pitch block 900 on the blade assembly 100 is installed in the groove on the side of the pitch slider 403; three The stops are fixed to the top of the side hole of the propeller hub 200 by bolts to prevent the propeller mounting nut 800 from loosening; the bottom square hole of the rotating shaft of the drive assembly 300 and the top square shaft of the lead screw shaft 401 form a wedge fit; 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 rotating shaft of the sensor connector 1003 and the sensor 1002 are fitted by a form surface fit; the sensor connector 1003 and the bottom groove of the lead screw shaft 401 are fitted together.

[0033] Example 2

[0034] like Figure 2 As shown, most of the structures in this embodiment are the same as in Embodiment 1. The difference is that the sensor assembly 1001 includes a sensor 1002 and a sensor connector 1003. 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 driven 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. 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 suddenly stalls due to a malfunction, sensor 1002 detects a sudden change in the displacement value of the pitch slider 403, which does not match the value calculated by the ECU. At this point, the motor speed fed back by the motor end speed sensor 1002 within the drive assembly 300 can be compared. If the difference in motor speed is not significant, it can be determined that the internal transmission gear of the drive assembly 300 is faulty, possibly due to wear, breakage, or deformation. If the motor speed also changes significantly, it may be a fault in the drive software or the motor itself. The system can determine the cause of the fault and adjust the propeller speed and pitch angle to stabilize the fuselage attitude, facilitating further safety measures. Compared to Embodiment 1, where sensor 1002 collects the rotation angle of the lead screw shaft 401, Embodiment 2 directly collects the displacement of the pitch slider 403 after transmission through the lead screw shaft 401 and lead screw nut 402. Its feedback is more direct, efficient, and accurate, but its layout and structural design are more complex.

[0036] Example 3

[0037] like Figure 3 As shown, most of the structures in this embodiment are the same as in Embodiment 1. The difference is 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, compared with Embodiment 1, the sensor 1002 collects the rotation angle of the lead screw shaft 401, Embodiment 2 collects the displacement of the variable pitch slider 403, and Embodiment 3 collects the pitch angle of the blade assembly 100. The feedback directly feeds back to the final control target, which is the most efficient and accurate. However, the space is small and the parts arrangement and structural design are the most complex.

[0038] The specific embodiments described herein are merely illustrative examples of the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications to the described specific embodiments or adopt similar methods to replace them, but without departing from the scope defined by the spirit of this utility model.

Claims

1. An electric pitch control mechanism for aircraft propeller blades, characterized in that, The device includes a blade assembly, a hub, a drive assembly, and a pitch control module. The blade assembly is connected and installed to the hub, and the pitch control module is installed inside the hub. The pitch control module is equipped with a sensor assembly for real-time acquisition of changes in the pitch control module's angle or distance. The blade assembly is connected to the pitch control module and uses the sensor assembly to acquire and provide real-time feedback on changes in the pitch control module's angle or distance, thereby controlling changes in the pitch angle.

2. The aircraft propeller electric pitch control mechanism according to claim 1, characterized in that, The pitch control module includes a lead screw shaft, a lead screw nut, and a pitch slider. The square hole at the bottom of the output shaft of the drive assembly forms a wedge fit with the square shaft at the top of the lead screw shaft and transmits the driving torque to the lead screw shaft. The lead screw nut is threaded to the lead screw shaft. As the lead screw shaft rotates, the lead screw nut can slide up and down axially. The pitch slider is bolted to the lead screw nut. During operation, the pitch slider and the lead screw nut slide up and down together along the axial direction under the drive of the lead screw nut.

3. An aircraft propeller electric pitch control mechanism 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 and lower angular contact bearings respectively mate with the upper and lower stepped surfaces of the lead 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 mounting groove at the bottom of the propeller hub. The upper cover plate is connected to the top of the propeller hub by bolts.

4. An aircraft propeller electric pitch control mechanism according to claim 1 or 2, characterized in that, The blade assembly and the hub are also provided with needle roller bearings, thrust needle roller bearings and blade mounting nuts. The three sets of blade assemblies are respectively engaged with the stepped surfaces of three holes evenly distributed on the side of the hub through needle roller bearings. The blade mounting nuts are engaged with the stepped surface in the middle of the blade assembly through thrust needle roller bearings and are connected to the holes evenly distributed on the side of the hub through threads to lock the blade assembly and the hub.

5. The aircraft propeller electric pitch control 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 stuck in the inner groove of the blade mounting nut.

6. The aircraft propeller electric pitch control mechanism according to claim 4, characterized in that, The blade assembly and the pitch slider are connected by an eccentric slot. When the pitch slider slides up and down, the blade assembly will also rotate along its own axis and change the pitch angle.

7. The aircraft propeller electric pitch control mechanism according to claim 1, characterized in that, The blade assembly is equipped with a pitch block, which is installed in the groove on the side of the pitch slider. Three stops are fixed to the top of the blade hub side hole by bolts to prevent the blade mounting nuts from loosening.

8. The aircraft propeller electric pitch control 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 sensor's rotating shaft via a form-fit. The sensor connector also engages with the groove at the bottom of the lead screw shaft to provide real-time feedback on the angular position of the lead screw shaft.

9. The aircraft propeller electric pitch control mechanism according to claim 2, characterized in that, The sensor assembly includes a sensor and a sensor connector. The sensor connector is in contact 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 lead screw shaft and lead 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 lead screw shaft through the output shaft according to the feedback value and forms a control feedback loop.

10. An aircraft propeller electric pitch control 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 to acquire the pitch angle of the blade assembly.

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