Reconfigurable wheel-track composite propulsion mechanism

Abstract

The application provides a reconfigurable wheel-track composite propulsion mechanism, which greatly improves the passability of the propulsion mechanism in a track mode. The mechanism comprises a frame assembly, a wheel hub, a chain wheel set, an elastic track, a main shaft clutch and a chassis clutch. The elastic track is an annular belt with teeth on the inner surface. The chain wheel set is a plurality of chain wheels with external teeth uniformly and evenly distributed along the circumferential surface of the elastic track. The chain wheels are engaged with the elastic track through the external teeth. One side of the frame assembly is hinged to the wheel hub, and the other side is hinged to the chain wheel set. The deformation of the frame assembly drives the deformation of the elastic track, thereby switching between the wheel mode and the track mode. In the track mode, the elastic track forms a polygonal structure symmetric about the vehicle main shaft, and the front and rear supporting sections of the propulsion mechanism are track sections formed by smooth connection of straight sections and circular arc sections in sequence. The vehicle main shaft is connected to the wheel hub through the main shaft clutch, and the chassis clutch is installed between the wheel hub and the vehicle body.

Description

Technical Field

[0001] This invention relates to a propulsion mechanism, specifically a reconfigurable wheel-track composite propulsion mechanism, belonging to the field of industrial machinery technology. Background Technology

[0002] Currently, vehicles primarily use two propulsion mechanisms: tires and tracks. On paved roads or relatively flat natural terrain, wheeled vehicles offer superior mobility; however, in unpaved off-road environments, tracked vehicles have a clear advantage in traverse. Reconfigurable wheel-track hybrid propulsion mechanisms can switch between these two configurations, combining the speed of tires with the high traverse capability of tracks, resulting in greater terrain adaptability.

[0003] Patent WO03029070A1 proposes a reconfigurable wheel-track hybrid propulsion mechanism that uses a hydraulic cylinder and leaf springs as the actuation mechanism for configuration conversion. During wheel-track configuration conversion, the hydraulic cylinder extends outward to push the auxiliary wheel outward, thereby opening the elastic track and ultimately achieving a triangular track configuration. This propulsion mechanism can be used on wheeled vehicles, motorcycles, or wheelchairs to increase their off-road capability. However, this mechanism requires high track elasticity, and changes in track tension during configuration conversion can affect propulsion efficiency. In tracked mode, the approach and departure angles of the propulsion mechanism are small, making it difficult to meet obstacle crossing requirements. Furthermore, in both modes, the drive sprocket of this propulsion mechanism directly bears the load of the ground surface, resulting in lower reliability of the gear teeth in off-road environments.

[0004] The wheel-track hybrid propulsion mechanism proposed in patent WO2020223295A1 uses three linear push rods symmetrically distributed around the circumference to achieve configuration conversion. Each linear push rod ends in a track drive sprocket. During configuration conversion, all three push rods simultaneously push the sprocket outwards, achieving the conversion from a wheeled to a triangular track configuration. The mechanism contains two independently controlled clutches, capable of locking the propulsion mechanism frame to the chassis in tracked mode and locking the propulsion mechanism to the vehicle's main axle in wheeled mode. However, in tracked mode, the mechanism requires push rods to support the vehicle body, thus placing higher demands on its performance. In tracked mode, the sprocket needs to extend radially while simultaneously rotating around its own axis; the coupling of the kinematic pairs increases the difficulty of designing the structure and power transmission system. The propulsion mechanism has a relatively complex structure and requires high-speed rotation, which also presents significant challenges to its dynamic balance design.

[0005] Patent WO2020223298A1 proposes a wheel-track hybrid propulsion mechanism capable of interchangeable wheel and polygonal track configurations. This propulsion mechanism has two concentrically rotating rigid support plates on both the inner and outer sides. In wheel mode, they are staggered, while in track mode, they overlap. During the conversion from wheel to track configuration, the drive motor rotates the support plates until they overlap, and the track drive sprocket extends outward under the action of a push rod, ultimately achieving a polygonal track configuration. Although this polygonal track configuration has larger approach and departure angles compared to a triangular track configuration, in track mode, the front and rear support sections of the propulsion mechanism are straight segments with constant approach and departure angles, resulting in poor maneuverability in track mode. Similar to the aforementioned patent, this structure also involves the coupling of sprocket translational and rotational pairs, making the design of the power transmission system more challenging. Meanwhile, the rigid support plates on both sides of the propulsion mechanism support the entire vehicle weight. This design makes it difficult to guarantee its reliability structurally, and it also reduces the comfort of the passengers.

[0006] Patent CN105564148B proposes a wheel-track-leg composite propulsion mechanism based on rim deformation. The rim of this propulsion mechanism has a four-segment structure, with each segment hinged end-to-end. During configuration conversion, the deformable slider moves linearly along the groove of the wheel frame, and the rim folds inward to an "∞" shape under the action of a spring tension rod. The track drive wheel, track driven wheel, and two track support wheels support the track, forming a quadrilateral track. This mechanism uses a motor to drive the track drive wheel to wind the track, driving the vehicle; and uses a circular wheel drive motor to drive the wheel frame, changing the angle between the wheel frame and the ground to achieve the conversion between tracked and straight-leg modes. Due to the use of two sets of motors, the propulsion mechanism has a relatively complex structure. In wheeled mode, the rim is only radially supported by the wheel frame, resulting in a large overall deformation.

[0007] Patent CN107140045B proposes a spoke-rotating, variable-form wheel-track composite walking mechanism. This mechanism uses a segmented wheel rim, a deformable motor, and deformable spokes to achieve configuration conversion. The wheel rim has a segmented structure, consisting of several arc-shaped rim pieces hinged end-to-end. During the conversion from wheeled to tracked configuration, the deformable motor drives the deformable spokes to rotate, and the deformable spokes are connected to the arc-shaped rim pieces via grooves, thus enabling configuration conversion. However, this mechanism uses a fixed wheel frame to support the wheel rim, and the length of the wheel frame cannot be changed. Therefore, during the conversion from wheeled to tracked configuration, the arc-shaped rim pieces will interfere with each other, which is technically difficult to achieve.

[0008] In summary, the aforementioned wheel-track hybrid locomotive mechanisms all suffer from the following intractable problems:

[0009] (1) Most wheel-track composite propulsion mechanisms are triangular in track mode, with small approach and departure angles, making it difficult to meet the passability requirements in off-road environments;

[0010] (2) The overall structure of the above-mentioned wheel-track composite propulsion mechanism and the track sprocket drive scheme are quite complex, and the design of the power transmission system is quite difficult.

[0011] (3) Some of the above solutions use linear push rods to support the vehicle body, while others use support plates to support the vehicle body. Such support solutions have low reliability and may fail when faced with complex road loads.

[0012] (4) In the above scheme, there is no built-in suspension device for the propulsion mechanism, which results in the structural components of the propulsion mechanism directly bearing the ground load, resulting in low reliability. Summary of the Invention

[0013] In view of this, the present invention provides a reconfigurable wheel-track hybrid propulsion mechanism, which can greatly improve the passability of the propulsion mechanism in track mode.

[0014] A reconfigurable wheel-track hybrid propulsion mechanism includes: a frame assembly, wheel hubs, sprocket sets, elastic tracks, a main shaft clutch, and a chassis clutch;

[0015] The elastic track is an annular belt with teeth on its inner surface;

[0016] The sprocket assembly consists of 2N sprockets with external teeth evenly spaced along the circumferential direction on the inner circumferential surface of the elastic track, where N is an integer greater than 4; at least two sprockets serve as drive sprockets, and the remaining sprockets serve as support sprockets; the sprockets mesh with the elastic track through their external teeth.

[0017] One side of the frame assembly is hinged to the wheel hub, and the other side is hinged to the sprocket assembly. The deformation of the frame assembly causes the elastic track to deform, thereby switching between wheeled mode and tracked mode. In tracked mode, the elastic track forms a polygonal structure that is symmetrical about the vehicle's main shaft, and the front and rear support sections of the propulsion mechanism are track sections formed by the smooth connection of straight and circular arc sections in sequence.

[0018] The vehicle's main shaft is connected to the wheel hub via a main shaft clutch, and the chassis clutch is installed between the wheel hub and the vehicle body. In wheel mode, the main shaft clutch is engaged, the chassis clutch is disengaged, and the wheel-track composite propulsion mechanism rotates at high speed with the vehicle's main shaft. In track mode, the main shaft clutch is disengaged, the chassis clutch is engaged, the drive wheel rotates, and the elastic track is wound around it.

[0019] In a preferred embodiment of the present invention, the frame assembly includes an inner frame and an outer frame; the inner frame and the outer frame have the same structure and are respectively disposed at both ends of the axial direction of the sprocket assembly;

[0020] The inner frame includes two frame units arranged symmetrically along the axis of the propulsion mechanism, each frame unit including two wheel rim connecting rods, two auxiliary connecting rods and a wheel rim actuator;

[0021] The wheel rim actuators are arranged along the horizontal radial direction of the propulsion mechanism. In each frame unit, one end of each of the two wheel rim connecting rods and one end of the wheel rim actuator are hinged to the sprocket assembly. The other ends of each of the two wheel rim connecting rods are hinged to the wheel hub through a secondary connecting rod, and the hinge point between the wheel rim connecting rod and the secondary connecting rod is located on the sprocket assembly. The other end of the wheel rim actuator is hinged to the wheel hub. The wheel rim actuators in the two frame units can simultaneously extend and retract along the horizontal radial direction of the propulsion mechanism to achieve structural deformation of the inner frame.

[0022] In a preferred embodiment of the present invention, the frame unit further includes two secondary linkage actuators; the secondary linkage actuators are capable of axial extension and retraction.

[0023] Each secondary link is provided with a corresponding secondary link actuator; one axial end of the secondary link actuator is hinged to a sprocket located in the vertical direction, and the other axial end is hinged to the middle of the corresponding secondary link.

[0024] In a preferred embodiment of the present invention, the auxiliary linkage actuator is a passive linear motion mechanism, comprising: a sliding sleeve, an actuator shaft, and a spring; one end of the sliding sleeve is coaxially fitted outside the actuator shaft and slides in cooperation with the actuator shaft, and the other end is provided with a hinge seat for hinged with the auxiliary linkage; the other end of the actuator shaft extends out of the sliding sleeve and is provided with a hinge seat for hinged with the support wheel.

[0025] Shoulders are provided on the outer circumference of the sliding sleeve and the outer circumference of the actuator shaft extending out of the sliding sleeve. The spring is fitted outside the sliding sleeve and the actuator shaft and is located between the two shoulders.

[0026] In a preferred embodiment of the present invention, the drive wheel includes a drive motor, a sprocket, and a reducer connected in series; the sprocket has external teeth that can mesh with the teeth on the inner side of the elastic track for transmission; in wheel mode, the drive wheel does not rotate; in track mode, the drive motor drives the sprocket to rotate through the reducer.

[0027] In a preferred embodiment of the present invention, the wheel hub is a split structure, including an inner wheel hub and an outer wheel hub, wherein the inner frame is hinged to the inner wheel hub and the outer frame is hinged to the outer wheel hub.

[0028] In a preferred embodiment of the present invention, the elastic track is an integral track made of flexible material.

[0029] In a preferred embodiment of the present invention, the elastic track is a segmented track, which is formed by connecting several track plates end to end in sequence, and adjacent track plates are connected by an elastic device.

[0030] Beneficial effects:

[0031] (1) Currently, most wheel-track composite propulsion mechanisms are triangular in track mode, with small and constant approach and departure angles, which makes it difficult to meet the passability requirements in off-road environments. In this invention, in track mode, the elastic track forms an axisymmetric polygonal structure, and the front and rear support sections of the propulsion mechanism are track sections formed by smooth connection of straight and circular arc sections. Thus, in track mode, the approach and departure angles of the propulsion mechanism are not constant, which greatly improves the passability of the propulsion mechanism in track mode.

[0032] (2) In this invention, an inner frame and an outer frame are set up, and the inner frame and the outer frame deform synchronously to ensure the reliability of the wheel-track composite propulsion mechanism mode switching. The structure is simple and the design is easy.

[0033] (3) In this invention, the secondary linkage actuator can be used as a built-in suspension, which can buffer the ground load on the support wheel connected to it and improve the reliability of the corresponding secondary linkage.

[0034] (4) In this invention, the secondary connecting rod serves to connect the hub and the rim connecting rod. Compared with the schemes disclosed in patents CN 107140045B and CN105564148B, in this invention, the length of the spokes (i.e., the secondary connecting rod) remains unchanged, and the position of the hinge point with the rim connecting rod also remains unchanged. Therefore, the frame assembly of this structural form has better rigidity, and the support performance of the inner and outer frames is better in wheeled and tracked modes.

[0035] (5) The drive wheel of the present invention integrates the drive motor, sprocket and reducer into one unit, with a high degree of integration, compact structure and simpler track sprocket drive scheme. Attached Figure Description

[0036] Figure 1 A three-dimensional structural diagram of the wheeled track-driven composite propulsion mechanism in wheeled mode;

[0037] Figure 2 A three-dimensional view of the wheel-track hybrid propulsion mechanism in tracked mode;

[0038] Figure 3 To support the exploded view of the wheelset;

[0039] Figure 4 This is one embodiment of a secondary linkage actuator;

[0040] Figure 5 To adopt Figure 4The diagram shows a simplified structural diagram of the wheel-track hybrid propulsion mechanism in track mode, representing an example of a secondary linkage actuator.

[0041] Among them: 1-inner frame, 2-outer frame, 3-wheel hub, 31-inner wheel hub, 32-outer wheel hub, 4-support wheel, 41-support wheel, 42-support wheel axle, 43-support wheel wear plate, 5-drive wheel, 6-elastic track, 7-main shaft clutch, 8-chassis clutch, 9-vehicle main shaft, 11-wheel rim connecting rod, 12-secondary connecting rod, 13-wheel rim actuator, 14-secondary connecting rod actuator, 141-sliding sleeve, 142-actuator shaft, 143-spring. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] This embodiment provides a reconfigurable wheel-track hybrid propulsion mechanism, which has good maneuverability and a compact structure.

[0044] The side of the propulsion mechanism closest to the vehicle body is defined as the inner side, and the side furthest from the vehicle body is defined as the outer side.

[0045] like Figure 1 and Figure 2 As shown, the reconfigurable wheel-track composite propulsion mechanism includes: a frame assembly, a wheel hub 3, a sprocket assembly, an elastic track 6, a main shaft clutch 7, and a chassis clutch 8.

[0046] The sprocket assembly includes a support wheel 4 and a drive wheel 5; the hub 3 is a split structure, including an inner hub 31 and an outer hub 32; the frame assembly includes an inner frame 1 and an outer frame 2.

[0047] The elastic track 6 is an annular belt with teeth on its inner surface; the sprocket assembly consists of several sprockets with external teeth evenly spaced along the circumferential direction on the inner circumferential surface of the elastic track 6 (all sprockets have the same outer diameter), wherein at least two sprockets serve as drive sprockets and the remaining sprockets serve as support sprockets; the sprockets mesh with the elastic track 6 through their external teeth. Preferably, two sprockets located in the horizontal radial direction of the elastic track 6 are used as drive sprockets.

[0048] The elastic track 6 can be a one-piece track made of flexible materials, such as timing belts or rubber tracks; or it can be a segmented track, with each segment being a relatively rigid track plate, connected by elastic devices between or within the track plates. The more sprockets there are, the smaller the diameter of each sprocket, and the smaller the gap between adjacent sprockets, the better the envelope of the support sprocket assembly fits to a circle in wheel configuration. It is important to note that the number of sprockets must be even. In this example, the sprocket assembly includes 16 sprockets, with 14 serving as support sprockets 4 and two as drive sprockets 5.

[0049] The inner frame 1 and the outer frame 2 have the same structure and are respectively set at both ends of the axial direction of the composite propulsion mechanism. One side of the inner frame 1 is hinged to the inner hub 31, and the other side is hinged to the inner end of the sprocket assembly. One side of the outer frame 2 is hinged to the outer hub 32, and the other side is hinged to the outer side of the sprocket assembly. Through the structural deformation of the inner frame 1 and the outer frame 2, the elastic track 6 is deformed, so that it switches between wheel mode and track mode. In track mode, the elastic track forms a polygonal structure that is symmetrical about the main shaft of the vehicle, and the front support section and the rear support section of the propulsion mechanism are track sections formed by the smooth connection of straight sections and arc sections in sequence.

[0050] The following describes one implementation method using the inner frame 1 as an example.

[0051] The inner frame 1 includes: two lines along the vertical centerline of the propulsion mechanism (e.g., Figure 5 The frame units are arranged symmetrically front and back along axis b). Each frame unit includes: two wheel rim links 11, two auxiliary links 12, one wheel rim actuator 13, and two auxiliary link actuators 14. That is, in this example, the inner frame 1 has four wheel rim links 11.

[0052] The rim actuator 13 is a linear motion device, such as an electric actuator or a hydraulic cylinder; the rim actuator 13 is arranged radially along the horizontal direction of the propulsion mechanism. In each frame unit, one end of two rim connecting rods 11 is hinged together and to one end of the rim actuator 13, with the hinge points of all three located on corresponding sprockets. The other ends of each of the two rim connecting rods 11 are hinged to the inner hub 31 via a secondary connecting rod 12 (correspondingly, in the outer frame 2, the rim connecting rod is hinged to the outer hub via a secondary connecting rod), that is, one end of the secondary connecting rod 12 is hinged to the rim connecting rod 11, and the other end is hinged to the inner hub 31; and the hinge points of the rim connecting rod 11 and the secondary connecting rod 12 are located on corresponding sprockets. The other end of the rim actuator 13 is hinged to the inner hub 31. Specifically, in this example, the fixed end of the wheel rim actuator 13 is hinged to the inner wheel hub 31, and the actuating end (i.e., the telescopic end) is hinged to the wheel rim connecting rod 11. Thus, the frame unit moves along the horizontal centerline of the propulsion mechanism (e.g., ...). Figure 5 The axis in the middle is symmetrical from top to bottom (a).

[0053] The wheel rim actuators 13 in the two frame units can extend and retract radially at the same time, thereby driving the two sets of wheel rim connecting rods 11 and their corresponding auxiliary connecting rods 12 to simultaneously generate displacement and rotation, realizing the structural deformation of the inner frame 1.

[0054] Furthermore, each secondary link 12 is provided with a corresponding secondary link actuator 14. One end of the secondary link actuator 14 is hinged to the sprocket located in the vertical direction (correspondingly, the two secondary link actuators 14 located above are respectively hinged to the sprockets located in the vertical direction above, and the two secondary link actuators 14 located below are respectively hinged to the sprockets located in the vertical direction below), and the other end is hinged to the middle part of the corresponding secondary link 12 (here, "middle part" refers to the area between the two ends of the secondary link 12, and is not limited to the middle position).

[0055] The distance between the two hinge points of the secondary linkage actuator 14 changes during the wheel track configuration conversion. The specific change depends on the lengths of the rim link 11, secondary link 12, and rim actuator 13, as well as the position of the hinge point of the secondary linkage actuator 14 on the secondary link 12. Therefore, to accommodate this change, the secondary linkage actuator 14 employs a passive linear motion mechanism, such as a sliding spline shaft coaxial with the spring.

[0056] Figure 4 This is a specific embodiment of the secondary linkage actuator 14 as a passive linear motion mechanism. In this embodiment, the secondary linkage actuator 14 includes: a sliding sleeve 141, an actuator shaft 142, and a spring 143. One end of the sliding sleeve 141 is coaxially fitted onto the outside of the actuator shaft 142, slidingly engaging with it. The other end is provided with a hinge seat for hinged connection with the secondary linkage 12. The other end of the actuator shaft 142 extends out of the sliding sleeve 141 and is provided with a hinge seat for hinged connection with a sprocket. Shoulders are provided on the outer circumference of both the sliding sleeve 141 and the outer circumference of the actuator shaft 142 extending out of the sliding sleeve 141. The spring 143 is fitted onto the outside of the sliding sleeve 141 and the actuator shaft 142, located between the two shoulders. Thus, when the sliding sleeve 141 and the actuator shaft 142 slide and stretch relative to each other, the spring 143 is stretched.

[0057] In this example, as Figure 1 and Figure 2 As shown, each support wheel 4 is supported at both ends on the inner frame 1 and the outer frame 2 respectively; specifically, except for the two support wheels 4 located vertically above and below, the remaining support wheels 4 are all supported on the wheel rim connecting rod 11.

[0058] like Figure 3As shown, the support wheel 4 includes: a support wheel body 41, a support wheel shaft 42, and a support wheel wear-resistant plate 43. The support wheel body 41 is a cylindrical structure with a central through hole. Teeth are machined on the outer circumference of the support wheel body 41 for meshing with the teeth on the inner surface of the elastic track 6. The support wheel shaft 42 is coaxially located in the central hole of the support wheel body 41 (i.e., the support wheel body 41 is rotatably supported outside the support wheel shaft 42). The support wheel body 41 can rotate relative to the support wheel shaft 42 along the axis of the support wheel shaft 42. The support wheel wear-resistant plates 43 are installed after the two ends of the support wheel shaft 42 extend out of the support wheel body 41. Then, the support wheel shaft 42 is connected to the lugs on the wheel rim connecting rod 11. The end of the auxiliary connecting rod actuator 14 is directly fitted onto the outside of the support wheel shaft 42 in the upper and lower support wheel groups and is hinged to the support wheel shaft 42.

[0059] In this example, the two drive wheels 5 are located at opposite ends in a horizontal radial position; thus, the 14 support wheels 4 and the two drive wheels 5 are evenly spaced along the circumference.

[0060] The drive wheel 5 includes a drive motor, a sprocket, and a reducer connected in series; the sprocket has external teeth that can mesh with the teeth on the inner side of the elastic track 6 for transmission; in wheel mode, the drive wheel 5 does not rotate; in track mode, the drive motor drives the sprocket to rotate through the reducer, and the sprocket's teeth wind around the track to drive the vehicle forward.

[0061] The vehicle's main axle 9 is connected to the wheel hubs via a main axle clutch 7. The inner wheel hub 31 and outer wheel hub 32 are mounted on the housing of the main axle clutch 7. The main axle clutch 7 has two sets of friction plates: one set connected to the vehicle's main axle 9, and the other set connected to the housing of the main axle clutch 7. The housing of the main axle clutch 7 connects the inner wheel hub 31 and the outer wheel hub 32. Thus, the main axle clutch 7 can lock or release the wheel hubs from the vehicle's main axle 9, thereby locking or releasing the inner frame 1 and outer frame 2 from the vehicle's main axle 9. The chassis clutch 8 is installed between the inner wheel hub 31 and the vehicle body, enabling locking or releasing the inner frame 1 from the vehicle chassis.

[0062] like Figure 1 As shown, in wheel mode, the main shaft clutch 7 locks the wheel hub to the vehicle's main shaft 9, and the chassis clutch 8 disengages (i.e., the inner frame 1 is disengaged from the vehicle chassis). The entire wheel-track composite propulsion mechanism rotates at high speed with the vehicle's main shaft 9, driving the vehicle forward in wheel mode; as shown... Figure 2 As shown, in tracked mode, the chassis clutch 8 engages to lock the vehicle chassis and inner wheel hub 31, the main shaft clutch 7 disengages, the vehicle main shaft 9 does not rotate, the drive wheel 5 rotates, and the track drives the vehicle forward.

[0063] like Figure 5As shown, in tracked mode, the propulsion mechanism has an axisymmetric polygonal structure, and the front and rear support sections are track sections formed by the smooth connection of straight and circular arc sections. The approach and departure angles are not constant. In this example, with 14 support wheels 4, there are three approach and departure angles, namely α1, α2, and α3, which can improve the propulsion mechanism's passability on off-road surfaces to a certain extent.

[0064] It should be noted that the number of approach angles or departure angles is related to the number of support wheels 4 in the propulsion mechanism. The more support wheels 4 there are, the more approach and departure angles there are. However, the adjacent α... i The smaller the gap between them.

[0065] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A reconfigurable wheel-track composite propulsion mechanism, characterized in that, include: Frame assembly, wheel hubs, sprocket sets, flexible tracks, spindle clutch, and chassis clutch; The elastic track is an annular belt with teeth on its inner surface; The sprocket set consists of 2N sprockets with external teeth evenly spaced along the circumferential direction on the inner circumferential surface of the elastic track, where N is an integer greater than 4. At least two sprockets serve as drive wheels, and the remaining sprockets serve as support wheels; the sprockets mesh with the elastic track via external teeth. One side of the frame assembly is hinged to the wheel hub, and the other side is hinged to the sprocket assembly. The deformation of the frame assembly causes the elastic track to deform, thereby switching between wheeled mode and tracked mode. In tracked mode, the elastic track forms a polygonal structure that is symmetrical about the vehicle's main shaft, and the front and rear support sections of the propulsion mechanism are track sections formed by the smooth connection of straight and circular arc sections in sequence. The vehicle's main shaft is connected to the wheel hub via a main shaft clutch, and the chassis clutch is installed between the wheel hub and the vehicle body. In wheel mode, the main shaft clutch is engaged, the chassis clutch is disengaged, and the wheel-track composite propulsion mechanism rotates at high speed with the vehicle's main shaft. In track mode, the main shaft clutch is disengaged, the chassis clutch is engaged, the drive wheel rotates, and the elastic track is wound around it. The frame assembly includes an inner frame and an outer frame; the inner frame and the outer frame have the same structure and are respectively arranged at both ends of the axial direction of the sprocket assembly; The inner frame includes two frame units symmetrically arranged along the axis of the propulsion mechanism. Each frame unit includes two wheel rim connecting rods, two auxiliary connecting rods, and a wheel rim actuator. The wheel rim actuator is arranged along the horizontal radial direction of the propulsion mechanism. In each frame unit, one end of the two wheel rim connecting rods and one end of the wheel rim actuator are hinged to the sprocket assembly. The other end of each of the two wheel rim connecting rods is hinged to the wheel hub through an auxiliary connecting rod, and the hinge point between the wheel rim connecting rod and the auxiliary connecting rod is located on the sprocket assembly. The other end of the wheel rim actuator is hinged to the wheel hub. The wheel rim actuators in the two frame units can simultaneously extend and retract along the horizontal radial direction of the propulsion mechanism, realizing the structural deformation of the inner frame. The frame unit also includes two secondary linkage actuators; the secondary linkage actuators are capable of axial extension and retraction. Each secondary link is provided with a corresponding secondary link actuator; one axial end of the secondary link actuator is hinged to a sprocket located in the vertical direction, and the other axial end is hinged to the middle of the corresponding secondary link. The auxiliary linkage actuator is a passive linear motion mechanism, comprising: a sliding sleeve, an actuator shaft, and a spring; one end of the sliding sleeve is coaxially fitted outside the actuator shaft and slides in cooperation with the actuator shaft, and the other end is provided with a hinge seat for hinged with the auxiliary linkage; the other end of the actuator shaft extends out of the sliding sleeve and is provided with a hinge seat for hinged with the support wheel. Shoulders are provided on the outer circumference of the sliding sleeve and the outer circumference of the actuator shaft extending out of the sliding sleeve. The spring is fitted outside the sliding sleeve and the actuator shaft and is located between the two shoulders.

2. The reconfigurable wheel-track composite propulsion mechanism as described in claim 1, characterized in that, The drive wheel includes a drive motor, a sprocket, and a reducer connected in series; the sprocket has external teeth that can mesh with the teeth on the inner side of the elastic track for transmission; in wheel mode, the drive wheel does not rotate; in track mode, the drive motor drives the sprocket to rotate through the reducer.

3. The reconfigurable wheel-track composite propulsion mechanism as described in claim 1, characterized in that, The wheel hub has a split structure, including an inner wheel hub and an outer wheel hub. The inner frame is hinged to the inner wheel hub, and the outer frame is hinged to the outer wheel hub.

4. The reconfigurable wheel-track composite propulsion mechanism as described in claim 1, characterized in that, The elastic track is a one-piece track made of flexible material.

5. The reconfigurable wheel-track composite propulsion mechanism as described in claim 1, characterized in that, The elastic track is a segmented track, formed by connecting several track plates end to end in sequence, with adjacent track plates connected by an elastic device.

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