A main-passive compact variable stiffness rotary joint applied to a morphing aircraft

Abstract

The present invention provides a main-passive compact variable stiffness rotary joint applied to a morphing aircraft, belonging to the field of morphing aircraft. It solves the problems of slow variable stiffness speed and small variable stiffness range of traditional aircraft joints. It includes a first housing with a switching drive assembly arranged inside; a stiffness adjustment mechanism, which includes a stiffness adjustment outer housing rotatably arranged at one end of the first housing and a planetary gear train coaxially arranged inside the stiffness adjustment outer housing. The switching drive assembly is used to drive the sun gear and a plurality of planetary gears in the planetary gear train to rotate. A second gear ring that meshes with all the planetary gears in the planetary gear train is coaxially arranged on a support disk. A roller cage coaxially arranged with the second gear ring is arranged on the support disk, and the wall surfaces of the rollers are in contact with both the second gear ring and the stiffness adjustment outer housing; a position adjustment mechanism, one end of which is connected to the stiffness adjustment outer housing and this end is rotatably connected to the support disk, and is used to drive the stiffness adjustment outer housing to rotate. It is mainly used as a joint on an aircraft.

Description

Technical Field

[0001] The present invention belongs to the field of morphing aircraft, and particularly relates to a main-passive compact variable-stiffness rotary joint applied to a morphing aircraft. Background Art

[0002] With the fierce competition among countries around the world for air strategic interests, rapid strike and high-maneuver flight have become important directions for the development of aircraft. Traditional fixed-configuration aircraft are designed according to specific tasks and it is difficult to always maintain the optimal flight performance in complex and changeable flight environments. Therefore, various countries have taken morphing aircraft as the research focus, and by adjusting the aircraft configuration in real time, the aircraft can always maintain excellent flight characteristics when performing different tasks. The "morphing" of a morphing aircraft is achieved through each joint in the transmission mechanism, and the transmission joint is the structural basis for the mechanism to transmit motion and force. The stiffness of each mechanism joint of the aircraft is an important parameter affecting the aerodynamic elastic efficiency and stability of the aircraft, and is related to factors such as the joint position and the mechanism shape. Although traditional constant-stiffness joints can achieve fast and accurate position control, they cannot guarantee the optimization of the aircraft's aerodynamic performance in a time-varying environment.

[0003] At present, there are many problems in the variable-stiffness joint technology of aircraft, such as: slow variable-stiffness speed, small stiffness adjustment range, and difficulty in coping with complex flight tasks; small load-bearing capacity, large structural size, and low joint integration; poor real-time performance and low accuracy in identifying joint model parameters and variables, making it difficult to accurately control the joint state; there is no mature theory for the design of aircraft mechanisms based on variable-stiffness joints. The above problems seriously limit the application of variable-stiffness joint technology in morphing aircraft. Therefore, it is crucial to develop a variable-stiffness joint mechanism with fast stiffness adjustment speed, large variable-stiffness range, strong load-bearing capacity, and high integration for a morphing aircraft to achieve the established deformation tasks and ensure the mechanism performance. Summary of the Invention

[0004] In view of this, the present invention aims to propose a main-passive compact variable-stiffness rotary joint applied to a morphing aircraft to solve the problems of slow variable-stiffness speed and small range of traditional aircraft joints.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A main-passive compact variable-stiffness rotary joint applied to a morphing aircraft, comprising:

[0006] A first housing, with a switching drive assembly disposed inside;

[0007] The stiffness adjustment mechanism includes a stiffness adjustment outer shell rotatably provided at one end of the first housing and a planetary gear train coaxially arranged inside the stiffness adjustment outer shell. The switching drive assembly is used to drive the sun gear and multiple planetary gears in the planetary gear train to rotate. A second gear ring that meshes with all the planetary gears in the planetary gear train is coaxially arranged on a support disk. The sun gear and all the planetary gears are rotatably connected to the support disk. A roller cage coaxially arranged with the second gear ring is provided on the support disk. A plurality of rollers are rotatably arranged on the roller cage. The wall surface of each roller abuts against the second gear ring and the stiffness adjustment outer shell.

[0008] The position adjustment mechanism is connected to the stiffness adjustment outer shell at one end and is rotatably connected to the support disk at this end, and is used to drive the stiffness adjustment outer shell to rotate.

[0009] Furthermore, the planetary gear train further includes a planet carrier, a sun gear shaft and a planetary gear shaft. The sun gear and the planet carrier are coaxially arranged on the sun gear shaft. A plurality of planetary gear shafts are circumferentially and evenly arranged on the planet carrier. Each planetary gear is connected to the corresponding planetary gear shaft through an elastic member. The elastic member is used to adjust the stiffness during rotation and keep the applied force acting vertically along the axial direction on the sun gear shaft. The sun gear shaft is rotatably connected to the first housing.

[0010] Furthermore, the elastic member is an e-shaped beam structure member with an e-shaped cross section.

[0011] Furthermore, the position adjustment mechanism further includes a mounting disk, a harmonic reducer, a position adjustment motor and a position adjustment mechanism housing. One end face of the mounting disk is connected to the stiffness adjustment outer shell and is rotatably connected to the support disk, and the other end face is connected to the position adjustment mechanism housing. The position adjustment motor is arranged inside the adjustment mechanism housing. The position adjustment motor is connected to the mounting disk through the harmonic reducer.

[0012] Furthermore, a stiffness adjustment transmission mechanism and a connection and separation mechanism are provided inside the first housing; the stiffness adjustment transmission mechanism includes a driving assembly and a sliding transmission assembly; the connection and separation mechanism includes two electromagnetic disks arranged oppositely along the axial direction of the sliding transmission assembly and a magnetic clutch assembly slidably disposed between the two electromagnetic disks. The magnetic clutch assembly is connected to the sliding transmission assembly. The two electromagnetic disks are used to drive the magnetic clutch assembly to drive the sliding transmission assembly to contact or separate from the output end of the driving assembly. The driving assembly is fixedly connected to the first-side electromagnetic disk, and the second-side electromagnetic disk is connected to the inner bottom wall of the first housing. A first gear ring is provided on the peripheral wall of the first housing. The other end of the sliding transmission assembly is slidably matched with the sun gear shaft of the planetary gear train. When the magnetic clutch assembly contacts the first-side electromagnetic disk, the sliding transmission assembly contacts the output end of the driving assembly. At this time, the magnetic clutch assembly disengages from the first gear ring. When the magnetic clutch assembly contacts the second-side electromagnetic disk, the sliding transmission assembly disengages from the output end of the driving assembly. At this time, the magnetic clutch assembly meshes with the first gear ring. When the magnetic clutch assembly is located between the two electromagnetic disks, the magnetic clutch assembly disengages from the first gear ring.

[0013] Furthermore, the driving assembly includes a gear box, bevel gears, an elastic coupling, a motor support seat, and a stiffness adjustment motor. The gear box is connected to the first-side electromagnetic disk. The bevel gear is rotatably connected inside the gear box, and the other end passes through the gear box and is connected to the output end of the stiffness adjustment motor through the elastic coupling. The stiffness adjustment motor is connected to the first-side electromagnetic disk through the motor support seat.

[0014] Furthermore, the sliding transmission assembly is a bevel gear shaft, one end of which is slidably disposed inside the gear box and the axis is perpendicular to the bevel gear, the other end is slidably matched with the sun gear shaft, and the middle part is connected to the magnetic clutch assembly.

[0015] Furthermore, the magnetic clutch assembly includes a sliding connection assembly, a permanent magnet connection disk, and a gear disk. There are two permanent magnet connection disks, which are connected to both side end faces of the gear disk. The gear disk is connected to the sliding transmission assembly through the sliding connection assembly. When the gear disk moves to a preset position, it meshes with the first gear ring.

[0016] Furthermore, a compression spring is provided between each permanent magnet connection disk and the corresponding electromagnetic disk.

[0017] Furthermore, the first housing includes a stiffness adjustment transmission mechanism housing, a connection and separation mechanism housing, and an intermediate disk. The stiffness adjustment transmission mechanism housing and the connection and separation mechanism housing are coaxially and sequentially connected. The opening on the side of the connection and separation mechanism housing away from the stiffness adjustment transmission mechanism housing is blocked by the intermediate disk. The first gear ring is connected to the inner peripheral wall of the connection and separation mechanism housing. The sun gear shaft is rotatably connected to the intermediate disk. The second-side electromagnetic disk is connected to the intermediate disk.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. This joint uses an E-shaped beam structure member to complete the connection between the planetary gear and the planetary gear shaft, replacing the traditional spring as the elastic unit. By driving its own rotation, the stiffness can be adjusted. Compared with the variable stiffness joint that requires a rotation-translation conversion mechanism to adjust the stiffness through linear motion, the design of the stiffness adjustment mechanism is simplified, and a large range of stiffness adjustment can be achieved in a compact space;

[0020] 2. In terms of the stiffness adjustment efficiency of this joint, since the force applied to the sun gear shaft caused by the rotation of the E-shaped beam structure member is almost perpendicular to the rotation direction of the sun gear shaft, and the stiffness adjustment motor does not need to provide additional torque to offset the spring preload, therefore, compared with other variable stiffness joints based on spring preloading, this design can achieve stiffness adjustment with low power consumption cost while improving the bearing capacity;

[0021] 3. This joint can achieve both active and passive adjustment methods of stiffness, enabling the morphing aircraft to select the most favorable joint stiffness according to different flight environments and flight states, increasing its flexibility while ensuring reliability, and improving the aeroelastic efficiency and stability;

[0022] 4. This joint uses the interaction between the electromagnet and the permanent magnet to complete the connection and separation of the stiffness adjustment transmission mechanism, and can achieve rapid adjustment of the stiffness;

[0023] 5. This joint decouples the two parts of stiffness adjustment and position adjustment, and can achieve separate drive adjustment of stiffness and position without affecting each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 is a schematic diagram of the overall external structure of a main-passive compact variable stiffness rotary joint applied to a morphing aircraft according to the present invention;

[0026] Figure 2 is a schematic diagram of the connection relationship between the connection and separation mechanism housing and the first gear ring according to the present invention;

[0027] Figure 3 is a schematic diagram of the overall internal structure of a main-passive compact variable stiffness rotary joint applied to a morphing aircraft according to the present invention;

[0028] Figure 4 is a schematic diagram of the structure of the drive assembly according to the present invention;

[0029] Figure 5 Explosion diagram of the connection and separation mechanism described in the present invention;

[0030] Figure 6 Explosion diagram of the stiffness adjustment mechanism described in the present invention;

[0031] Figure 7 Top view of the stiffness adjustment mechanism described in the present invention;

[0032] Figure 8 Schematic diagram of the connection state of the e-shaped beam structure member, planetary gear shaft and planetary gear described in the present invention;

[0033] Figure 9 Schematic diagram of the deformation of the e-shaped beam structure member described in the present invention when in the first state;

[0034] Figure 10 Schematic diagram of the deformation of the e-shaped beam structure member described in the present invention when in the second state;

[0035] Figure 11 Explosion diagram of the position adjustment mechanism described in the present invention;

[0036] Figure 12 As described in the present invention Figure 1 Rear view;

[0037] Figure 13 As described in the present invention Figure 12 A-A sectional view.

[0038] Stiffness adjustment transmission mechanism 1; Stiffness adjustment transmission mechanism housing 101; Gearbox 102; Bevel gear 103; Bevel gear shaft 104; Bevel gear shaft bearing 105; Elastic coupling 106; Motor support 107; Stiffness adjustment motor 108; Connection and separation mechanism 2; Connection and separation mechanism housing 201; Electromagnetic disk 202; Central block 203; O-ring 204; Retaining block 205; Permanent magnet connection disk 206; Support column 207; Gear disk 208; Spring hub disk 209; Compression spring 210; Intermediate disk 211; Stiffness adjustment mechanism 3; Planet carrier 301; Sun gear shaft 302; Sun gear 303; Planetary gear shaft 304; e-shaped beam structure member 305; Planetary gear 306; Gear shaft bearing 307; Second gear ring 308; Roller retainer 309; Roller 310; Stiffness adjustment housing 311; Position adjustment mechanism 4; Support disk 401; Ball 402; Small ball connection ring 403; Large ball connection ring 404; Mounting disk 405; Harmonic reducer 406; Position adjustment motor 407; Position adjustment mechanism housing 408. Detailed implementation mode

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention may be combined with each other. The described embodiments are only some of the embodiments of the present invention, rather than all of the embodiments.

[0040] It should be noted that the descriptions of directions such as "left", "right", "left side", "right side", "upper part", "lower part", "top", "bottom", etc. in the present invention are all defined 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 described structure must be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In the description of the present invention, the meaning of "a plurality" is more than two, unless otherwise specifically defined.

[0041] In the description of the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0042] Referring to the accompanying drawings to illustrate this embodiment, a main-passive compact variable stiffness rotary joint applied to a variant aircraft includes:

[0043] A first housing, inside which a switching drive assembly is arranged; the first housing as a whole is a closed housing, and can be arranged in a way of multi-segment splicing to achieve a state of being detachable and convenient for maintenance. In this application, a three-section separable structure is adopted for arrangement, which can partition different parts in terms of functions, and at the same time, when there is wear, the corresponding partition can be replaced according to actual needs.

[0044] A stiffness adjustment mechanism 3, including a stiffness adjustment outer shell 311 rotatably arranged at one end of the first housing and a planetary gear train coaxially arranged inside the stiffness adjustment outer shell 311. The switching drive assembly is used to drive the sun gear 303 and a plurality of planetary gears 306 in the planetary gear train to rotate. A second ring gear 308 meshing with all the planetary gears 306 in the planetary gear train is coaxially arranged on a support disk 401. The sun gear 303 and all the planetary gears 306 are rotatably connected to the support disk 401. A roller cage 309 coaxially arranged with the second ring gear 308 is arranged on the support disk 401. A plurality of rollers 310 are rotatably arranged on the roller cage 309, and the wall surface of each roller 310 abuts against the second ring gear 308 and the stiffness adjustment outer shell 311;

[0045] The position adjustment mechanism 4 has one end connected to the stiffness adjustment housing 311, and this end is rotatably connected to the support disk 401, and is used to drive the stiffness adjustment housing 311 to rotate. The position adjustment mechanism 4 is set as a separate unit, and the two parts of stiffness adjustment and position adjustment are decoupled, so that the separate drive adjustment of stiffness and position can be realized without mutual influence, improving the convenience of application.

[0046] In this embodiment, the planetary gear train further includes a planet carrier 301, a sun gear shaft 302, and a planet gear shaft 304. A sun gear 303 and a planet carrier 301 are coaxially arranged on the sun gear shaft 302. A plurality of planet gear shafts 304 are circumferentially and evenly arranged on the planet carrier 301. Each planet gear 306 is connected to the corresponding planet gear shaft 304 through an elastic member. The elastic member is used to adjust the stiffness during rotation and keep the applied force perpendicular to the sun gear shaft 302 along the axial direction. The sun gear shaft 302 is rotatably connected to the first housing. The elastic member is for deforming correspondingly during stiffness adjustment to achieve the effect of changing the stiffness.

[0047] In this embodiment, the elastic member is an e-shaped beam structure member 305, and the cross-section is e-shaped. Specifically, for the e-shaped structure, it includes a middle part and an edge part. The middle part is used to connect with the planet gear shaft 304, and the edge part is the free end of the e. The connection with the planet gear 306 is formed through the free end. Through the e-shaped structural design, when deforming, the force applied to the sun gear shaft caused by rotation can be almost perpendicular to the rotation direction of the sun gear shaft through the e-shaped structure, and the stiffness adjustment motor does not need to provide additional torque to offset the spring preload force. Therefore, compared with other variable stiffness joints based on spring preloading, this design can achieve stiffness adjustment with low power consumption cost while improving the bearing capacity.

[0048] In this embodiment, the position adjustment mechanism 4 further includes a mounting disk 405, a harmonic reducer 406, a position adjustment motor 407, and a position adjustment mechanism housing 408. One end face of the mounting disk 405 is connected to the stiffness adjustment housing 311 and is rotatably connected to the support disk 401, and the other end face is connected to the position adjustment mechanism housing 408. The position adjustment motor 407 is arranged in the adjustment mechanism housing 408. The position adjustment motor 407 is connected to the mounting disk 405 through the harmonic reducer 406. For the position adjustment motor 407 and the harmonic reducer 406, existing corresponding devices can be used, and the purpose is to drive the mounting disk 405. Specifically, the output end of the adjustment motor 407 is connected to the input end of the harmonic reducer 406, and the output end of the harmonic reducer 406 is connected to the mounting disk 405. Of course, it is not excluded that some other driving component can directly drive the mounting disk 405, and this setting method is still within the spirit of the present invention.

[0049] In this embodiment, a stiffness adjustment transmission mechanism 1 and a connection and separation mechanism 2 are arranged in the first housing; the stiffness adjustment transmission mechanism 1 includes a driving component and a sliding transmission component; the connection and separation mechanism 2 includes two electromagnetic disks 202 arranged axially opposite to each other along the sliding transmission component and a magnetic clutch assembly slidably arranged between the two electromagnetic disks 202. The magnetic clutch assembly is connected to the sliding transmission component. The two electromagnetic disks 202 are used to drive the magnetic clutch assembly to drive the sliding transmission component to contact or separate from the output end of the driving component. The driving component is fixedly connected to the first-side electromagnetic disk 202, and the second-side electromagnetic disk 202 is connected to the inner bottom wall of the first housing. A first gear ring is arranged on the peripheral wall of the first housing. The other end of the sliding transmission component is slidably matched with the sun gear shaft 302 of the planetary gear train. When the magnetic clutch assembly contacts the first-side electromagnetic disk 202, the sliding transmission component contacts the output end of the driving component. At this time, the magnetic clutch assembly disengages from the first gear ring. When the magnetic clutch assembly contacts the second-side electromagnetic disk 202, the sliding transmission component disengages from the output end of the driving component. At this time, the magnetic clutch assembly engages with the first gear ring. When the magnetic clutch assembly is located between the two electromagnetic disks 202, the magnetic clutch assembly disengages from the first gear ring. For the first gear ring, a separate gear ring can be used to connect with the peripheral wall of the first housing, or an integrated manner can be adopted for connection, which can be selected according to actual needs. For the specific connection form, the integration can be produced by means of integral die-casting or molding with a mold, and the separate gear ring form can be connected by bolts.

[0050] In this embodiment, the driving component includes a gear box 102, a bevel gear 103, an elastic coupling 106, a motor support base 107, and a stiffness adjustment motor 108. The gear box 102 is connected to the first-side electromagnetic disk 202. The bevel gear 103 is rotatably connected in the gear box 102 and the other end passes through the gear box 102 and is connected to the output end of the stiffness adjustment motor 108 through the elastic coupling 106. The stiffness adjustment motor 108 is connected to the first-side electromagnetic disk 202 through the motor support base 107. When in use, the stiffness adjustment motor 108 can transmit power to the bevel gear 103 through the elastic coupling 106, and when the sliding transmission group engages with the bevel gear 103, the power can be completely transmitted.

[0051] In this embodiment, the sliding transmission assembly is a bevel gear shaft 104, one end of which is rotatably and slidably disposed in the gearbox 102 with its axis perpendicular to the bevel gear 103, the other end is in sliding fit with the sun gear shaft 302, and the middle part is connected to the magnetic clutch assembly. The end of the bevel gear shaft 104 where the bevel gear is specifically provided is disposed in the gearbox 102. The bevel gear shaft 104 is connected to the gearbox 102 in a manner that can rotate and maintain relative sliding. Such a connection can be achieved using an existing structure and will not be elaborated here. For the bevel gear 103 and the bevel gear shaft 104, the bevel gear shaft bearings 105 are used to complete the corresponding connections, thereby reducing rotational friction, extending the service life, and reducing vibration and noise.

[0052] In this embodiment, the magnetic clutch assembly includes a sliding connection assembly, a permanent magnet connection disk 206, and a gear disk 208. Two permanent magnet connection disks 206 are provided and connected to both side end faces of the gear disk 208. The gear disk 208 is connected to the sliding transmission assembly through the sliding connection assembly, and the gear disk 208 meshes with the first toothed ring when moving to a preset position. The function of the permanent magnet connection disk 206 is to be attracted or repelled by the corresponding electromagnetic disk 202 on each side. Thus, under the combined driving action of the two electromagnetic disks 202 on both sides, the magnetic clutch assembly can move in one direction. For the electromagnetic disk 202, it can apply both an attractive force and a repulsive force to the permanent magnet connection disk 206. The corresponding power-on method can be selected according to actual needs. The electromagnetic disk 202 can be a commercially available existing product. The power-on method and the corresponding force change method are also prior arts and will not be elaborated here. The permanent magnet connection disk 206 has a magnetism that can be maintained for a long time. For the magnetic clutch assembly to be slidably disposed between the two electromagnetic disks 202, corresponding tracks are required. In this application, a plurality of support columns 207 are arranged between the two electromagnetic disks 202 in a certain pattern, so that the entire magnetic clutch assembly is in sliding fit with all the support columns 207. This can not only relatively fix the positions of the two electromagnetic disks 202 but also provide a preset track for the sliding of the magnetic clutch assembly, thereby enabling the magnetic clutch assembly to complete the corresponding sliding driving function. A more preferred method is to provide light holes corresponding to the positions of the support columns 207 on the magnetic clutch assembly, and a better effect can be achieved by sliding with a certain lubricating medium. Lubricating oil or grease can be selected according to actual needs. The center block 203, the O-ring 204, and the retaining block 205 are connected to the gear disk 208 by bolts and nuts to center and fix the positions of the lower bevel gear shaft 104 and the sun gear shaft 302, and enable the lower bevel gear shaft 104 and the sun gear shaft 302 to move following the above magnetic clutch assembly.

[0053] In this embodiment, a compression spring 210 is disposed between each permanent magnet connection disk 206 and the corresponding electromagnetic disk 202. The compression spring 210 is provided to facilitate resetting after the magnetic clutch assembly moves. Specifically, the compression spring 210 is fixedly installed on the permanent magnet connection disk 206 through a spring hub disk 209, and the other end can be connected to the electromagnetic disk 202 in a suitable manner according to actual needs. At the same time, it buffers during connection and separation to prevent damage to the mechanism caused by too fast speed, and the spring hub disk 209 can limit the position of the fixed compression spring 210.

[0054] In this embodiment, the first housing includes a stiffness adjustment transmission mechanism housing 101, a connection and separation mechanism housing 201, and an intermediate disk 211. The stiffness adjustment transmission mechanism housing 101 and the connection and separation mechanism housing 201 are coaxially and sequentially connected. The opening on the side of the connection and separation mechanism housing 201 away from the stiffness adjustment transmission mechanism housing 101 is blocked by the intermediate disk 211. The first gear ring is connected to the inner peripheral wall of the connection and separation mechanism housing 201. The sun gear shaft 302 is rotatably connected to the intermediate disk 211, and the second side electromagnetic disk 202 is connected to the intermediate disk 211.

[0055] The connection methods between various parts of the mechanism are as follows:

[0056] The gearbox 102 and the motor support base 107 in the stiffness adjustment transmission mechanism 1 are fixedly connected to the first side electromagnetic disk 202 in the connection and separation mechanism 2 by screws. The bevel gear shaft 104 in the stiffness adjustment transmission mechanism 1 is inserted into the center block 203 in the connection and separation mechanism 2. At the same time, the stiffness adjustment transmission mechanism housing 101 and the connection and separation mechanism housing 201 are connected by bolts and nuts. The connection and separation mechanism housing 201 and the intermediate disk 211 are connected by screws, so as to realize the fixed cooperation of the two parts of the mechanism. The intermediate disk 211 in the connection and separation mechanism 2 is connected to the second gear ring 308 and the roller cage 309 in the stiffness adjustment mechanism 3 by screws. The sun gear shaft 302 in the stiffness adjustment mechanism 3 is also inserted into the center block 203 in the connection and separation mechanism 2. At the same time, the intermediate disk 211 and the stiffness adjustment mechanism housing 311 are connected by balls 402 and large ball connection rings 404 to ensure that the two parts of the mechanism can rotate relative to each other while their positions are determined. The gear ring 308 and the roller cage 309 in the stiffness adjustment mechanism 3 are both connected to the support disk 401 in the position adjustment mechanism 4 by screws. The sun gear shaft 302 and the planetary gear shaft 304 in the stiffness adjustment mechanism 3 are inserted into the support disk 401 in the position adjustment mechanism 4 through gear shaft bearings 307. At the same time, the stiffness adjustment mechanism housing 311 and the mounting disk 405 are also connected by screws, so that the two can be fixed as a whole and rotate together, ensuring the position determination and precise transmission of the two parts of the mechanism.

[0057] The connection methods within each part mechanism are as follows:

[0058] In the stiffness adjustment transmission mechanism 1, after assembling the bevel gear shaft 104 first, the other end is sleeved into the bevel gear shaft bearing 105. Similarly, after mating the bevel gear 103 with the corresponding shaft and connecting it to the bevel gear shaft bearing 105, it is installed into the elastic coupling 106. Then, the stiffness adjustment motor 108 is installed at the other end of the elastic coupling 106 and is bolted to the motor support base 107. Next, the bevel gear shaft 104 and the bevel gear 103 are sleeved into the gearbox 102. The bevel gear shaft 104 is in contact connection with the gearbox 102 through the bevel gear shaft bearing 105, and the other end extends out of the gearbox 102. Finally, the two parts of the gearbox 102 are fixedly connected by bolts and nuts to complete the assembly of the stiffness adjustment transmission mechanism 1.

[0059] In the connection and separation mechanism 2, first, the upper and lower permanent magnet connection disks 206 and the holding blocks 205 are fixedly connected to the gear disk 208 by bolts and nuts. Then, the upper and lower O-ring 204 and the center block 203 are successively installed into the holding block 205 to form a magnetic clutch assembly. Next, the spring hub disk 209 and the compression spring 210 are installed on the electromagnetic disk 202. After the above-installed magnetic clutch assembly is sleeved onto the support column 207, both ends of the support column 207 are fixedly connected to the two electromagnetic disks 202. Finally, the lower electromagnetic disk 202 is connected to the intermediate disk 211 by screws to complete the assembly of the connection and separation mechanism 2.

[0060] In the stiffness adjustment mechanism 3, first, the e-shaped beam structural member 305 is fixedly connected to the planetary gear 306, and the sun gear 303 and the planetary gear 306 are respectively connected to the sun gear shaft 302 and the planetary gear shaft 304. Then, it is connected to the planet carrier 301 through the gear shaft bearing 307, and this whole is installed into the ring gear 308 to form a planetary gear train. Next, the roller 310 is installed on the roller cage 309, and the inner side of the roller 310 is kept in contact and fit with the outer side of the ring gear 308. Finally, the stiffness adjustment mechanism housing 311 is sleeved outside the roller 310, and the two are kept in contact and fit at the position where the diameter of the cam configuration inside the stiffness adjustment mechanism housing 311 is the smallest to complete the assembly of the stiffness adjustment mechanism 3.

[0061] In the position adjustment mechanism 4, first, the position adjustment motor 407 and the harmonic reducer 406 are installed and then screwed into the mounting plate 405. Then, the harmonic reducer 406 and the mounting plate 405 are fixedly connected by screws. Next, the support plate 401 is in contact connection with the mounting plate 405 through the ball 402 and the small ball connection ring 403. Finally, the position adjustment motor 407 is connected and fixed to the position adjustment mechanism housing 408 by screws to complete the assembly of the position adjustment mechanism 4.

[0062] During use, it is mainly divided into several working processes:

[0063] Active stiffness adjustment working process: First, by changing the external current direction of the electromagnetic disk 202, the first-side electromagnetic disk 202 applies an attractive force to the magnetic clutch assembly, and the second-side electromagnetic disk 202 applies a repulsive force to the magnetic clutch assembly, causing it to connect to the first-side electromagnetic disk 202 and drive the bevel gear shaft 104 to move upward, so that the bevel gear shaft 104 meshes with the bevel gear 103. At the same time, the stiffness adjustment motor 108 drives the sun gear shaft 302 and the sun gear 303 to rotate after being decelerated by meshing transmission, and then drives the planetary gear shaft 304, the planetary gear 306 and the e-shaped beam structure member 305 inside it to rotate around its own axis, realizing the active adjustment of the joint stiffness. At this time, the gear disk 208 does not mesh with the first tooth ring of the connection and separation mechanism housing 201.

[0064] Passive stiffness adjustment working process: First, by changing the external current direction of the electromagnetic disk 202, the first-side electromagnetic disk 202 applies a repulsive force to the magnetic clutch assembly, and the second-side electromagnetic disk 202 applies an attractive force to the magnetic clutch assembly, causing it to connect to the second-side electromagnetic disk 202 and drive the bevel gear shaft 104 to move downward, so that the bevel gear shaft 104 disengages from the bevel gear 103. At this time, the gear disk 208 meshes with the first tooth ring of the connection and separation mechanism housing 201. When the aircraft structure connected to the housing is in different flight environments and flight states, the sun gear shaft 302 and the sun gear 303 are driven to rotate through the magnetic clutch assembly, and then the planetary gear shaft 304, the planetary gear 306 and the e-shaped beam structure member 305 inside it are driven to rotate around their own axes, realizing the passive adjustment of the joint stiffness.

[0065] Position adjustment working process: The position adjustment motor 407 is started, and after being decelerated by the harmonic reducer 406, it drives the mounting plate 405 to rotate, and then drives the stiffness adjustment mechanism housing 311 fixedly connected to the mounting plate 405 to rotate. At this time, under the action of the balls 402, the small ball connection ring 403 and the large ball connection ring 404, the stiffness adjustment transmission mechanism 1, the connection and separation mechanism 2, the stiffness adjustment mechanism 3 except the stiffness adjustment mechanism housing 311 and the support plate 401 all remain stationary, and the stiffness adjustment mechanism housing 311 rotates relative to other mechanisms, and torque is transmitted by frictionally squeezing the internal structure of the stiffness adjustment mechanism 3 through the rollers 310, realizing the position angle adjustment of the joint mechanism. At the same time, by changing the external current direction of the electromagnetic disk 202, both the upper and lower electromagnetic disks 202 apply repulsive forces to the magnetic clutch assembly, causing it to be located in the middle position between the two. At this time, the gear disk 208 does not mesh with the first tooth ring of the connection and separation mechanism housing 201, ensuring that the stiffness adjustment and the position adjustment do not affect each other.

[0066] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. According to the content of this specification, many modifications and variations can be made. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention.

Claims

1. An active-passive compact variable stiffness rotary joint for a morphing aircraft, characterized in that: include: A first housing, in which a switching drive assembly is disposed; The stiffness adjustment mechanism (3) comprises a stiffness adjustment housing (311) rotatably arranged at one end of a first housing and a planetary gear train coaxially arranged in the stiffness adjustment housing (311), wherein the switching drive assembly is used to drive a sun gear (303) and a plurality of planetary gears (306) in the planetary gear train to rotate, a second gear ring (308) in the planetary gear train meshing with all the planetary gears (306) is coaxially arranged on a support disk (401), the sun gear (303) and all the planetary gears (306) are rotatably connected to the support disk (401), a roller retainer (309) coaxially arranged with the second gear ring (308) is arranged on the support disk (401), a plurality of rollers (310) are rotatably arranged on the roller retainer (309), and a wall surface of each roller (310) abuts against the second gear ring (308) and the stiffness adjustment housing (311); A position adjustment mechanism (4), one end of which is connected to the stiffness adjustment housing (311) and the other end of which is rotatably connected to the support plate (401), and is used to drive the stiffness adjustment housing (311) to rotate; The planetary gear system further comprises a planet carrier (301), a sun gear shaft (302) and a planet gear shaft (304); the sun gear (303) and the planet carrier (301) are coaxially arranged on the sun gear shaft (302); a plurality of planet gear shafts (304) are evenly distributed circumferentially on the planet carrier (301); each of the planet gears (306) is connected to a corresponding planet gear shaft (304) via an elastic member; the elastic member is used to adjust the rigidity during rotation and to maintain the applied force on the sun gear shaft (302) in a vertical direction along the axial direction; the sun gear shaft (302) is rotatably connected to the first housing; The elastic member is an e-shaped beam-like structural member (305) with an e-shaped cross section; The first housing is provided with a rigidity-adjusting transmission mechanism (1) and a connection and separation mechanism (2); the rigidity-adjusting transmission mechanism (1) comprises a driving component and a sliding transmission component; the connection and separation mechanism (2) comprises two electromagnetic disks (202) arranged axially opposite to each other along the sliding transmission component, and a magnetic clutch assembly slidably arranged between the two electromagnetic disks (202); the magnetic clutch assembly is connected to the sliding transmission component; the two electromagnetic disks (202) are used to drive the magnetic clutch assembly to drive the sliding transmission component to contact or separate from the output end of the driving component; the driving component is fixedly connected to the electromagnetic disk (202) on the first side; the electromagnetic disk (202) on the second side is connected to the electromagnetic disk (202) on the second side. The first housing is connected to the bottom wall on the inner side; a first gear ring is provided on the peripheral wall of the first housing; the other end of the sliding transmission component is slidably matched with the sun gear shaft (302) of the planetary gear system; when the magnetic clutch assembly contacts the first side electromagnetic disk (202), the sliding transmission component contacts the output end of the drive component, at which time the magnetic clutch assembly is disengaged from the first gear ring; when the magnetic clutch assembly contacts the second side electromagnetic disk (202), the sliding transmission component is disengaged from the output end of the drive component, at which time the magnetic clutch assembly is engaged with the first gear ring; when the magnetic clutch assembly is located between the two electromagnetic disks (202), the magnetic clutch assembly is disengaged from the first gear ring.

2. The active-passive compact variable stiffness rotary joint for a morphing aircraft according to claim 1, characterized in that: The position adjustment mechanism (4) further comprises a mounting plate (405), a harmonic reducer (406), a position adjustment motor (407) and a position adjustment mechanism housing (408); one end surface of the mounting plate (405) is connected to the stiffness adjustment housing (311) and is rotationally connected to the support plate (401); the other end surface is connected to the position adjustment mechanism housing (408); the position adjustment motor (407) is arranged in the adjustment mechanism housing (408); and the position adjustment motor (407) is connected to the mounting plate (405) via the harmonic reducer (406).

3. The active-passive compact variable stiffness rotary joint for a morphing aircraft according to claim 1, characterized in that: The drive assembly comprises a gearbox (102), a bevel gear (103), an elastic coupling (106), a motor support seat (107) and a stiffness adjustment motor (108); the gearbox (102) is connected to the first-side electromagnetic disk (202); the bevel gear (103) is rotatably connected in the gearbox (102) and the other end of the bevel gear (103) passes through the gearbox (102) and is connected to an output end of the stiffness adjustment motor (108) via the elastic coupling (106); the stiffness adjustment motor (108) is connected to the first-side electromagnetic disk (202) via the motor support seat (107).

4. The active-passive compact variable stiffness rotary joint for a morphing aircraft according to claim 3, characterized in that: The sliding transmission component is a bevel gear shaft (104), one end of which is slidably disposed in the gear box (102) with the axis perpendicular to the bevel gear (103), the other end of which is slidably matched with the sun gear shaft (302), and the middle part of which is connected to the magnetic clutch assembly.

5. The active-passive compact variable stiffness rotary joint for a morphing aircraft according to claim 1, 3 or 4, characterized in that: The magnetic clutch assembly comprises a sliding connection component, a permanent magnetic connection disk (206) and a gear disk (208); two permanent magnetic connection disks (206) are provided and connected to the end surfaces on both sides of the gear disk (208); the gear disk (208) is connected to the sliding transmission component via the sliding connection component; and the gear disk (208) meshes with the first gear ring when moving to a preset position.

6. The active-passive compact variable stiffness rotary joint for a morphing aircraft according to claim 5, characterized in that: A compression spring (210) is arranged between each permanent magnetic connection disk (206) and the electromagnetic disk (202) on the corresponding side.

7. An active-passive compact variable stiffness rotary joint for a morphing aircraft according to claim 1, 3, 4 or 6, characterized in that: The first housing comprises a rigidity adjustment transmission mechanism housing (101), a connection and separation mechanism housing (201) and an intermediate disk (211); the rigidity adjustment transmission mechanism housing (101) and the connection and separation mechanism housing (201) are coaxially connected in sequence; an opening of the connection and separation mechanism housing (201) away from the rigidity adjustment transmission mechanism housing (101) is blocked by the intermediate disk (211); the first gear ring is connected to the inner peripheral wall of the connection and separation mechanism housing (201); the sun gear shaft (302) is rotationally connected to the intermediate disk (211); and the second side electromagnetic disk (202) is connected to the intermediate disk (211).

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