Variable pitch mechanism of ducted fan

Abstract

The invention discloses a ducted fan variable-pitch mechanism which comprises a variable-pitch ducted fan body, the variable-pitch ducted fan body comprises a duct, a duct motor, a variable-pitch assembly, a propeller hub and blades are sequentially arranged in the duct, the propeller hub adopts die assembly design, a motor shaft is arranged at the output end of the duct motor, the propeller hub is arranged on the motor shaft, and the variable-pitch assembly is arranged on the motor shaft. The paddles are connected with the variable pitch shaft through a connecting mechanism; the connecting mechanism comprises a positioning block arranged at the blade root part of the blade, and a positioning groove is formed in one end of the variable pitch shaft; a movable ring and a fixed ring are arranged on the inner side of the variable-pitch assembly and are connected with each other; the movable ring is connected with a push rod sliding block, the push rod sliding block is connected with an eccentric column, an eccentric column groove in sliding connection with the push rod sliding block is formed in the propeller hub, and the eccentric column is connected with the eccentric column groove in a matched mode; the ducted fan is reasonable in layout, compact in structure, small in number of connecting pieces and high in modularization degree, the variable-pitch requirement of the ducted fan is met, and the ducted fan has high-efficiency performance under different working conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of ducted fans, and in particular, to a pitch-changing mechanism for a ducted fan. Background Art

[0002] The ducted fan is used as a power device in distributed electric propulsion aircraft, and has core advantages such as high efficiency in aerodynamics, low noise, and high safety. The propeller of a fixed-pitch ducted fan can only have high efficiency within a certain rotational speed range, and it is difficult to meet the high-efficiency requirements of the aircraft during the high-power vertical takeoff and landing stage and the cruise stage. Designing a pitch-changing mechanism for a ducted fan to achieve the pitch-changing function of the ducted fan propeller to meet the performance requirements of distributed electric propulsion aircraft at different stages is an important issue. At present, some pitch-changing mechanisms have been published. The Chinese patent application for invention with the application number CN202111063534.5 proposes an intelligent and efficient electric constant-speed variable-pitch propeller system. The propeller motor shaft is a hollow structure, and a pitch-changing push rod is passed through it. A pitch-changing blade component and a pitch-changing push rod drive component are respectively arranged at both ends of the pitch-changing push rod. The structure is compact, but at the same time, it has high requirements for the structure of the propeller motor. The Chinese patent application for invention with the application number CN202210106088.X proposes a variable-pitch fan and its pitch-changing method. The blade rotates freely relative to the hub around the pitch-changing axis. By changing the rotational speed of the hub, the blade can rotate relative to the hub under the action of inertia to change the pitch angle of the blade, but the pitch angle of the blade cannot be actively controlled. The Chinese patent application for invention with the application number CN202310602629.2 proposes a variable-pitch propeller hub structure. By installing parts such as a pitch-changing shaft, a thrust bearing, and a deep groove ball bearing inside the upper hub and the lower hub, the radial dimension of the entire mechanism is reduced. The pitch-changing is achieved by connecting the blade clamp and the pitch-changing pull rod, but the number of connecting parts is large, and the number of blades that can be installed on its hub is small. The Chinese patent application for invention with the application number CN202111303755.5 proposes a coaxial contra-rotating propeller drive system with independent pitch-changing. The front propeller realizes pitch-changing through the pitch-changing push rod with a hollow structure of the motor shaft, and the rear propeller realizes pitch-changing through the pitch-changing pull rod. The system designs two pitch-changing adjustment mechanisms to achieve non-interference in pitch-changing between the front propeller and the rear propeller, but the system structure is complex and the axial dimension is large. The Chinese patent application for invention with the application number CN202410211155.3 proposes a pitch-changing mechanism for the tail rotor of a large unmanned helicopter. The groove is movably connected with the eccentric column of the blade root joint, and the axial displacement of the groove drives the eccentric column to rotate to achieve blade pitch-changing. The number of structural connecting parts is large and the transmission structure is too long.

[0003] The present invention discloses a pitch-changing mechanism for a ducted fan; aiming at the problems of the hollow structure of the motor shaft and the excessive length of the transmission structure, the layout of the driving components is optimized; aiming at the problem of active pitch control, a dual-servo control drive is designed; aiming at the problem of the number of blades that can be installed on the hub, a clamping fit between the pitch-changing shaft and the blade is designed. The present invention enables the ducted fan to have a pitch-changing function, thereby meeting the high-efficiency requirements in different stages of the ducted fan and expanding the flight envelope of the ducted fan aircraft Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems existing in the prior art and provide a pitch-changing mechanism for a ducted fan

[0005] To achieve the above object, the technical solution provided by the present invention is: a pitch-changing mechanism for a ducted fan, including a pitch-changing ducted fan main body, the pitch-changing ducted fan main body includes a duct, a duct motor, a pitch-changing component, a hub and blades are sequentially arranged in the duct, the hub adopts a mold closing design, the output end of the duct motor is provided with a motor shaft, the hub is arranged on the motor shaft, and the blades are connected to the pitch-changing shaft through a connecting mechanism

[0006] The connecting mechanism includes a positioning block arranged at the root part of the blade, one end of the pitch-changing shaft is provided with a positioning groove, and the positioning block is inserted into the positioning groove to form a mechanical interlocking mechanism, and the other end of the pitch-changing shaft is provided with an eccentric column

[0007] The pitch-changing component is arranged between the motor end cover of the duct motor and the hub, a moving ring and a stationary ring are arranged inside the pitch-changing component, and the moving ring is connected to the stationary ring; a push rod slider is connected to the moving ring, and an eccentric column groove is arranged on the push rod slider, and the eccentric column is used in cooperation with the eccentric column groove

[0008] The push rod slider is connected to the moving ring through four fastening screws and is used to drive the axial movement of the push rod slider. The axial movement of the push rod slider along the motor shaft drives the eccentric column to rotate around the axis of the pitch-changing shaft

[0009] Preferably, the pitch-changing component includes a servo motor arranged on the end cover of the duct motor through a servo motor mounting screw and a servo motor mounting bracket, a servo motor arm is connected to the servo motor shaft of the servo motor, a pull rod is connected to the servo motor arm, an L-shaped connecting rod is connected to the pull rod, and a connecting rod is connected to the L-shaped connecting rod, and the connecting rod is connected to the stationary ring

[0010] Preferably, the servo motor arm, the pull rod, the L-shaped connecting rod, the connecting rod and the stationary ring form a multi-link transmission main body arranged on the support of the motor end cover. The L-shaped connecting rod is installed on the end cover of the duct motor through a bracket, and the end cover of the duct motor, the servo motor mounting bracket and the bracket are integrally designed

[0011] Preferably, the hub includes an upper hub and a lower hub. The upper hub and the lower hub are connected by hub fasteners, and a motor shaft nut for positioning is provided at the end of the motor shaft passing through the upper hub. Inside the hub, there are spaces for the push rod slider to move, needle bearing installation grooves, and thrust needle bearing installation grooves. Needle bearings and thrust needle bearings are respectively installed in the needle bearing installation grooves and the thrust needle bearing installation grooves, and the needle bearings and the thrust needle bearings are arranged outside the mechanical interlocking mechanism formed after the positioning block is inserted into the positioning groove.

[0012] Preferably, a deep groove ball bearing is rotatably connected to the moving ring, an outer ring of the deep groove ball bearing is sleeved with a stationary ring, the moving ring and the stationary ring are respectively provided with a moving ring retaining ring installation groove and a stationary ring retaining ring installation groove, and a moving ring shaft retaining ring and a stationary ring hole retaining ring are respectively arranged on the moving ring retaining ring installation groove and the stationary ring retaining ring installation groove.

[0013] Advantages of the present invention:

[0014] In the present invention, the connection between the blade and the pitch-changing shaft adopts a snap-fit design of a positioning block and a positioning groove, reducing the number of connecting parts, lowering the structural complexity, optimizing the structural dimensions, and increasing the number of blades that can be installed on the ducted fan. Moreover, the hub adopts a mold closing design, facilitating the installation and later maintenance of parts such as the push rod slider, the blade, and the pitch-changing shaft.

[0015] In the present invention, the push rod slider is connected with the eccentric column on the pitch-changing shaft to cooperate to achieve the function of changing the total pitch, reducing the number of transmission parts and connecting parts, optimizing the structural dimensions of the execution components of the mechanism, and improving the pitch-changing synchronization of the multi-blade. And the push rod slider is arranged inside the hub, reducing the aerodynamic influence of the pitch-changing mechanism on the ducted fan. At the same time, the hub also protects the push rod slider, reducing the risk of external damage and improving the service life.

[0016] In the present invention, the pitch-changing assembly is arranged between the hub and the motor end cover of the ducted fan, which not only reduces the aerodynamic influence of the pitch-changing assembly on the ducted fan but also avoids the excessive axial dimension of the multi-link transmission main body inside the pitch-changing assembly, thereby increasing the total weight of the mechanism. At the same time, the multi-link transmission is adopted in the pitch-changing assembly, increasing the structural flexibility. Under the condition of meeting the structural strength and pitch-changing requirements, the structural dimensions of the multi-link transmission are the smallest. And the integrated design of the motor end cover of the ducted fan, the servo mounting bracket, and the bracket of the L-shaped link is adopted, reducing the number of connecting parts, reducing the weight of the pitch-changing mechanism, and improving the structural strength.

[0017] In summary, the ducted fan pitch-changing mechanism provided by the present invention has a reasonable layout, a compact structure, a small number of connecting parts, a high degree of modularization, and has no requirement for a hollow structure of the motor shaft of the ducted fan, meeting the pitch-changing requirements of the ducted fan and achieving high-efficiency performance of the ducted fan under different working conditions. Description of the Drawings

[0018] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and shall not unduly limit the present invention.

[0019] Figure 1 is a schematic diagram of the overall structure of the preferred embodiment of the present invention;

[0020] Figure 2 is a schematic diagram of the structure of the pitch-changing assembly of the present invention;

[0021] Figure 3 is a schematic diagram of the connection between the moving ring and the stationary ring of the present invention;

[0022] Figure 4 is a schematic diagram of the blade layout structure of the present invention;

[0023] Figure 5 is an exploded view of the connection structure between the blade and the pitch-changing shaft of the present invention.

[0024] Reference numerals in the drawings:

[0025] 1 - duct, 2 - blade, 3 - upper hub, 4 - motor shaft, 5 - lower hub, 6 - pitch-changing assembly, 7 - duct motor, 8 - hub fastener, 9 - motor shaft fastening nut, 10 - push rod slider, 11 - moving ring, 12 - fastening screw, 13 - stationary ring, 14 - shaft retaining ring for moving ring, 15 - deep groove ball bearing, 16 - hole retaining ring for stationary ring, 610 - servo, 611 - servo arm, 612 - servo mounting screw, 620 - pull rod, 621 - L-shaped connecting rod, 622 - connecting rod, 630 - duct motor end cover, 101 - eccentric column groove, 220 - thrust needle roller bearing, 230 - needle roller bearing, 510 - needle roller bearing mounting groove, 520 - thrust needle roller bearing mounting groove, 210 - eccentric column, 211 - positioning groove, 212 - pitch-changing shaft, 240 - positioning block. Detailed embodiments

[0026] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The role of the accompanying drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be construed as a limitation on the protection scope of the present invention.

[0027] In the description of the present invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., refer to the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0028] In the description of the present invention, "a number of" means one or more, "a plurality of" means more than two, and understandings such as "greater than", "less than", "exceeding", etc. do not include the base number, and understandings such as "above", "below", "within", etc. include the base number. If there is a description of "first" and "second", it is only for the purpose of distinguishing technical features and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0029] In the description of the present invention, unless otherwise clearly defined, words such as "arrangement", "installation", "connection", etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0030] Referring to Figures 1-5 , a preferred embodiment of the present invention, a pitch-changing mechanism for a ducted fan, includes a pitch-changing ducted fan main body. The pitch-changing ducted fan main body includes a duct 1. Inside the duct 1, a duct motor 7, a pitch-changing component 6, a hub, and blades 2 are arranged in sequence. The number of blades 2 is not equal, ranging from 2 to 8. The hub adopts a mold clamping design. The output end of the duct motor 7 is provided with a motor shaft 4. The hub is arranged on the motor shaft 4. The blades 2 are connected to a pitch-changing shaft 212 through a connecting mechanism. The connection part between the blades 2 and the pitch-changing shaft 212 is located inside the hub.

[0031] The connecting mechanism includes a positioning block 240 arranged at the root part of the blade 2. One end of the pitch-changing shaft 212 is provided with a positioning groove 211. The positioning block 240 is inserted into the positioning groove 211 to form a mechanical interlocking mechanism. The other end of the pitch-changing shaft 212 is provided with an eccentric column 210. The design of clamping the positioning block and the positioning groove is adopted, eliminating the connecting parts, optimizing the overall structure of the blade and the pitch-changing shaft, and reducing the radial dimension of the pitch-changing mechanism.

[0032] The pitch-changing component 6 is arranged between the motor end cover 630 of the duct motor 7 and the hub, making the overall layout of the present invention compact and also reducing the aerodynamic influence on the ducted fan. Inside the pitch-changing component 6, a moving ring 11 and a stationary ring 13 are arranged. The moving ring 11 is connected to the stationary ring 13. A push rod slider 10 is connected to the moving ring 11. An eccentric column groove 101 is arranged on the push rod slider 10. The eccentric column 210 is used in cooperation with the eccentric column groove 101;

[0033] The push rod slider 10 is connected to the moving ring 11 by four fastening screws 12, which are used to drive the push rod slider 10 to move axially. The axial movement of the push rod slider 10 drives the pitch change shaft 212 to rotate. Specifically, the push rod slider 10 moves axially along the motor shaft 4 to drive the eccentric column 210 to rotate around the axis of the pitch change shaft 212; driving the push rod slider 10 to move axially reduces connecting parts, improves the overall structural strength, and realizes the variable total pitch of the ducted fan while meeting the small size requirements and high-intensity working conditions; reducing connecting parts, reducing structural complexity, and improving the synchronization of pitch change of the blade 2.

[0034] In this embodiment, the pitch variable assembly 6 includes a servo 610 arranged on the ducted motor end cover 630 through a servo mounting screw 612 and a servo mounting bracket, a servo arm 611 is connected to the servo shaft of the servo 610, a pull rod 620 is connected to the servo arm 611, an L-shaped connecting rod 621 is connected to the pull rod 620, a connecting rod 622 is connected to the L-shaped connecting rod 621, and the connecting rod 622 is connected to the fixed ring 13.

[0035] Preferably, the servos 610 are symmetrically arranged and are fastened by means of servo mounting screws 612. The present invention relies on two servos 610 to drive the variable pitch, thereby achieving a higher safety redundancy of the mechanism.

[0036] Furthermore, the servo arm 611, the pull rod 620, the L-shaped connecting rod 621, the connecting rod 622, and the fixed ring 13 form a multi-link transmission body arranged on the support of the motor end cover 630. The L-shaped connecting rod 621 is installed on the ducted motor end cover 630 through a bracket, and the ducted motor end cover 630, the servo mounting bracket and the bracket are integrated into a design.

[0037] Specifically, during the pitch change process, the servo 610 drives the servo arm 611 to rotate, which is transmitted to the fixed ring 13 and the movable ring 11 through a multi-link, and axially displaced on the motor shaft 4. The movable ring 11 then drives the push rod slider 10 to achieve axial movement, so that the axial movement of the push rod slider 10 drives the pitch change shaft 212 to rotate, and finally the pitch change shaft 212 drives the blades 2 to rotate, thereby realizing the pitch change of the ducted fan.

[0038] Preferably, a gear rack transmission can be used to replace a multi-link transmission body to achieve the axial movement of the stationary ring 13 .

[0039] Further, one end of the pull rod 622 is connected to the servo arm 611, and the other end of the pull rod 622 is connected to the input end of the L-shaped connecting rod 621, which can transmit the output torque of the servo 610 to the L-shaped connecting rod 621; the L-shaped connecting rod 621 is installed on the support of the ducted fan motor end cover 630. Since the distances from the input end to the output end of the L-shaped connecting rod 621 to the servo shaft are inconsistent, the torque amplification of the servo 610 is realized; one end of the connecting rod 622 is connected to the output end of the L-shaped connecting rod 621, and the other end of the connecting rod 622 is connected to the stationary ring 13, realizing the axial movement of the stationary ring 13; the multi-link transmission structure is compact and reasonably arranged, realizing the torque amplification of the servo 610 and meeting the pitch drive requirement of the ducted fan.

[0040] In this embodiment, the hub includes an upper hub 3 and a lower hub 5. The upper hub 3 and the lower hub 5 are connected by a hub fastener 8, and a motor shaft nut 9 for positioning is provided at the end of the motor shaft 4 passing through the upper hub 3; this facilitates the installation and later maintenance of the blade 2 and the pitch shaft 212; the space in the hub for the push rod slider 10 to move is provided with a needle bearing installation groove 510 and a thrust needle bearing installation groove 520. Specifically, the needle bearing installation groove 510 and the thrust needle bearing installation groove 520 are provided at the edge of the lower hub 5; a needle bearing 230 and a thrust needle bearing 220 are respectively installed in the needle bearing installation groove 510 and the thrust needle bearing installation groove 520. The needle bearing 230 and the thrust needle bearing 220 are arranged outside the mechanical interlocking mechanism formed after the positioning block 240 is inserted into the positioning groove 211. The space of the needle bearing installation groove 510, the thrust needle bearing installation groove 520 and the sliding groove for the movement of the push rod slider 10 inside the hub can make the structure of the present invention more compact.

[0041] In this embodiment, a deep groove ball bearing 15 is rotatably connected to the moving ring 11. An outer ring of the deep groove ball bearing 15 is sleeved with a stationary ring 13. The moving ring 11 and the stationary ring 13 are respectively provided with a moving ring retaining ring installation groove and a stationary ring retaining ring installation groove, and a moving ring shaft retaining ring 14 and a stationary ring hole retaining ring 16 are respectively arranged on the moving ring retaining ring installation groove and the stationary ring retaining ring installation groove.

[0042] Specifically, the moving ring shaft retaining ring 14 and the stationary ring hole retaining ring 16 prevent the deep groove ball bearing 15 from axially displacing; the moving ring 11 and the stationary ring 13 are arranged inside the pitch changing assembly 6, neither interfering with the movement of the pitch changing assembly 6 nor meeting the radial dimension requirements of the present invention.

[0043] In the present invention, the connection between the blade 2 and the pitch shaft 212 adopts a snap-fit design of a positioning block 240 and a positioning groove 211, reducing the number of connecting parts, reducing the structural complexity, optimizing the structural dimensions, and increasing the number of blades that can be installed on the ducted fan.

[0044] In the present invention, the hub is designed with a mold clamping structure, which facilitates the installation and subsequent maintenance of components such as the push rod slider 10, the blade 2, and the pitch change shaft 212.

[0045] In the present invention, the push rod slider 10 is cooperatively connected with the eccentric column 210 on the pitch change shaft 212 to achieve the function of changing the total pitch, reducing the number of transmission parts and connecting parts, optimizing the structural dimensions of the execution components of the mechanism, and improving the pitch change synchronization of the multi-blade propeller.

[0046] In the present invention, the push rod slider 10 is arranged inside the hub, reducing the aerodynamic influence of the pitch change mechanism on the ducted fan. At the same time, the hub also protects the push rod slider 10, reducing the risk of external damage and increasing the service life.

[0047] In the present invention, the pitch change assembly 6 is arranged between the hub and the end cover 630 of the ducted fan motor, which not only reduces the aerodynamic influence of the pitch change mechanism on the ducted fan but also avoids the excessive axial dimension of the pitch change mechanism, thereby increasing the total weight of the mechanism.

[0048] In the present invention, a multi-link transmission main body is adopted in the pitch change assembly 6 to increase the structural flexibility. Under the condition of meeting the structural strength and pitch change requirements, the structural dimensions of the multi-link transmission main body are minimized.

[0049] In the present invention, an integrated design of the end cover 630 of the ducted fan motor, the servo mounting bracket, and the bracket of the L-shaped link 621 is adopted to reduce the number of connecting parts, reduce the weight of the pitch change mechanism, and improve the structural strength.

[0050] In summary, a pitch change mechanism for a ducted fan provided by the present invention has a reasonable layout, a compact structure, a small number of connecting parts, a high degree of modularization, and has no requirement for a hollow structure of the ducted fan motor shaft, meeting the pitch change requirements of the ducted fan and achieving high-efficiency performance of the ducted fan under different working conditions.

[0051] On the premise of no conflict, those skilled in the art can freely combine and superimpose the above-mentioned additional technical features.

[0052] The above description is only the preferred implementation mode of the present invention. As long as the technical solutions that achieve the purpose of the present invention by basically the same means fall within the protection scope of the present invention.

Claims

1. A ducted fan pitch control mechanism, characterized in that: The variable pitch ducted fan comprises a main body, wherein the main body comprises a duct (1), a ducted motor (7), a variable pitch assembly (6), a hub and a blade (2) are arranged in sequence in the duct (1), the hub adopts a mold-matching design, a motor shaft (4) is arranged at the output end of the ducted motor (7), the hub is arranged on the motor shaft (4), and the blade (2) is connected to the variable pitch shaft (212) via a connecting mechanism; The connection mechanism comprises a positioning block (240) arranged at the root of the blade (2), a positioning groove (211) is arranged at one end of the pitch-changing shaft (212), the positioning block (240) is inserted into the positioning groove (211) to form a mechanical interlocking mechanism, and an eccentric column (210) is arranged at the other end of the pitch-changing shaft (212); The pitch-changing assembly (6) is arranged between the motor end cover (630) and the propeller hub of the ducted motor (7); a moving ring (11) and a stationary ring (13) are arranged on the inner side of the pitch-changing assembly (6); the moving ring (11) is connected to the stationary ring (13); a push rod slider (10) is connected to the moving ring (11); an eccentric column groove (101) is provided on the push rod slider (10); and the eccentric column (210) is used in conjunction with the eccentric column groove (101); The push rod slider (10) is connected to the moving ring (11) via four fastening screws (12) and is used to drive the push rod slider (10) to move axially. The push rod slider (10) moves axially along the motor shaft (4) to drive the eccentric column (210) to rotate around the axis of the pitch-changing shaft (212).

2. A ducted fan pitch control mechanism according to claim 1, characterized in that: The pitch-changing assembly (6) comprises a servo (610) arranged on a ducted motor end cover (630) via a servo mounting screw (612) and a servo mounting bracket, a servo arm (611) being connected to a servo shaft of the servo (610), a pull rod (620) being connected to the servo arm (611), an L-shaped connecting rod (621) being connected to the pull rod (620), a connecting rod (622) being connected to the L-shaped connecting rod (621), and the connecting rod (622) being connected to a stationary ring (13).

3. A ducted fan pitch control mechanism according to claim 2, characterized in that: The servo arm (611), the pull rod (620), the L-shaped connecting rod (621), the connecting rod (622), and the fixed ring (13) form a multi-link transmission body arranged on a support of the motor end cover (630). The L-shaped connecting rod (621) is installed on the ducted motor end cover (630) through a bracket, and the ducted motor end cover (630), the servo mounting bracket and the bracket are integrated into one design.

4. A ducted fan pitch control mechanism according to claim 1, characterized in that: The propeller hub comprises an upper propeller hub (3) and a lower propeller hub (5), wherein the upper propeller hub (3) and the lower propeller hub (5) are connected via a blade hub fastener (8), and a motor shaft nut (9) for positioning is arranged at the end of the motor shaft (4) passing through the upper propeller hub (3); a space for a push rod slider (10) to move, a needle roller bearing mounting groove (510) and a thrust needle roller bearing mounting groove (520) are arranged inside the propeller hub; a needle roller bearing (230) and a thrust needle roller bearing (220) are respectively installed in the needle roller bearing mounting groove (510) and the thrust needle roller bearing mounting groove (520), and the needle roller bearing (230) and the thrust needle roller bearing (220) are arranged outside a mechanical interlocking mechanism formed after a positioning block (240) is inserted into the positioning groove (211).

5. A ducted fan pitch control mechanism according to claim 4, characterized in that: A deep groove ball bearing (15) is rotatably connected to the moving ring (11), and a stationary ring (13) is sleeved on the outer ring of the deep groove ball bearing (15). The moving ring (11) and the stationary ring (13) are respectively provided with a moving ring retaining ring installation groove and a stationary ring retaining ring installation groove, and a moving ring shaft retaining ring (14) and a stationary ring hole retaining ring (16) are respectively provided on the moving ring retaining ring installation groove and the stationary ring retaining ring installation groove.

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