Wheel suitable for lunar environment and forming method thereof

Abstract

The invention provides a wheel suitable for the lunar environment and a forming method of the wheel, and belongs to the technical field of lunar exploration. The problems that due to the fact that an existing super-elastic metal tire is uneven in structural stress, concentrated in local stress, prone to being damaged in assembly and insufficient in overall mechanical coupling, the stability is poor, the buffering capacity is weak and the service life is short in the extreme environment of a manned lunar rover with high load, long period and strong impact are solved. The spring woven mesh cylinder comprises a spring woven mesh cylinder and a hub, the spring woven mesh cylinder is formed by spirally winding a plurality of variable-inner-diameter springs, the variable-inner-diameter springs are made of shape memory alloy, each variable-inner-diameter spring is of a structure with the inner diameter of the two ends being small and the inner diameter of the middle being large, and the hub comprises a rim structure and a transmission disc. The rim structure comprises chucks and a center ring, the two chucks are connected to the two sides of the center ring respectively, and the two sides of the end of the spring woven mesh cylinder are clamped by the two chucks. The lunar rover is mainly used for lunar rovers.

Description

Technical Field

[0001] This invention belongs to the field of lunar exploration technology, and in particular relates to a wheel suitable for the lunar environment and its molding method. Background Technology

[0002] As manned lunar exploration missions advance, the mobility and reliability of lunar rovers have become crucial to mission success. As the core component that directly contacts the lunar surface, the performance of the wheels is paramount. Traditional pneumatic or rubber tires are prone to aging and leaks in the extreme lunar environment (such as high vacuum, significant temperature variations, and strong radiation), posing a risk of failure. Rigid metal tires, on the other hand, have poor cushioning performance and are prone to permanent deformation, making them unsuitable for long-term exploration. Compared to unmanned lunar rovers, manned lunar rovers need to carry heavier payloads (including astronauts, life support systems, and scientific equipment) and possess higher speeds and longer mission durations. Therefore, the wheels not only need to provide excellent cushioning and shock absorption to ensure smooth driving and astronaut comfort, but also must possess superior wear resistance, an ultra-long service life, and stability to meet the challenges of long-distance, high-frequency travel in extreme environments such as sharp lunar debris and large temperature differences.

[0003] Against this backdrop, hyperelastic tires made from shape memory alloys (such as NiTi alloys) have emerged, with NASA's hyperelastic tires being a prime example. These tires demonstrate excellent load-bearing capacity and terrain adaptability, providing a new direction for lunar rover locomotion mechanisms. These tires utilize the hyperelastic deformation of materials to absorb impact energy, possessing potential advantages such as resistance to extreme environments and shock absorption, and are theoretically suitable for extraterrestrial exploration scenarios. However, current designs still face the following technical bottlenecks: Patent document CN117246074A discloses a wave-shaped tire for a manned lunar rover based on shape memory alloys. While this structure provides some elasticity and cushioning, it also has significant limitations. First, the tire relies on the ends of individual wave-shaped filaments clamped to the rim for fixation. Due to insufficient clamping stiffness and limited contact area, stress concentration easily occurs locally, leading to fatigue damage under prolonged loads and impacts. Second, the tread is composed of multiple independent wave-shaped filaments arranged circumferentially, lacking overall mechanical coupling and failing to form an effective load diffusion path. If the function of any filament weakens or becomes locally unstable, the overall performance of the tread is significantly affected, limiting its stability and reliability under heavy loads.

[0004] Patent document CN102448737A discloses a non-pneumatic tire including a helical spring. While the proposed helical spring tire employs a woven spring mesh structure, the method of fixing the spring ends still has significant limitations. According to its description, both the first and second ends of the helical spring pass through the rim axially and are fixed. This fixing method requires folding the entire woven spring mesh and reversing its fit onto the other side of the rim during assembly. For large, thick springs, this process is not only difficult to operate but also prone to irreversible bending or permanent damage, thus reducing the spring's superelastic recovery capability. Furthermore, although the structure uses a woven mesh, the fixing between the spring and the rim still involves inserting individual springs into the rim and tightening them. This type of point fixing method easily creates localized stress concentration at the spring-rim contact point, making it difficult to achieve uniform force distribution and hindering the achievement of high stability and long service life requirements.

[0005] In summary, although existing hyperelastic metallic tires have made some progress in terms of material properties and conceptual design, neither independent corrugated wire structures nor end-fixed woven helical spring structures fundamentally solve key problems such as uneven stress distribution, localized stress concentration, susceptibility to damage during assembly, and insufficient overall mechanical coupling. These structural defects limit the stability and lifespan of tires under high loads, long cycles, strong impacts, and extreme temperature environments, making it difficult to meet the stringent requirements of manned lunar rovers for high reliability, high cushioning capacity, and long-term service. Therefore, there is an urgent need for a new type of hyperelastic tire structure that achieves breakthroughs in rim fixing methods, elastic unit structure design, and overall force transmission mechanisms to truly adapt to the application needs of future manned lunar exploration missions. Summary of the Invention

[0006] In view of this, the present invention aims to propose a wheel suitable for the lunar environment and its molding method, so as to solve the problems of poor stability, weak buffering capacity and short life of existing superelastic metal tires due to uneven structural stress, local stress concentration, easy assembly damage and insufficient overall mechanical coupling, resulting in high load, long period and strong impact of manned lunar rover.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a wheel suitable for the lunar environment, comprising a spring-woven mesh cylinder and a hub. The spring-woven mesh cylinder is formed by multiple variable-diameter springs spirally wound together. The variable-diameter springs are made of shape memory alloy and have a structure with a small inner diameter at both ends and a large inner diameter in the middle. The hub includes a rim structure and a drive disc. Two rim structures are symmetrically connected to both sides of the drive disc by fasteners. The rim structure includes a clamping plate and a central ring. Two clamping plates are respectively connected to both sides of the central ring. The end of the spring-woven mesh cylinder is installed on the outside of the central ring. The two sides of the end of the spring-woven mesh cylinder are clamped by the two clamping plates. The end of the spring-woven mesh cylinder is connected to the clamping plate through a connector.

[0008] Furthermore, the two clamping discs are connected to both sides of the central ring by a first fastener, the two wheel rim structures are symmetrically connected to both sides of the transmission disc by a second fastener, and the two wheel rim structures are connected by a third fastener. The first, second, and third fasteners are lead screws or bolts.

[0009] Furthermore, the clamp is provided with a first connecting hole, a second connecting hole and a third connecting hole in a radial direction from the inside to the outside. Multiple first connecting holes and second connecting holes are evenly distributed circumferentially. One or more third connecting holes are grouped together, and multiple groups of third connecting holes are evenly distributed circumferentially. The first connecting hole is connected to a second fastener and a third fastener, the second connecting hole is connected to a first fastener, and the third connecting hole is connected to a spring braided mesh cylinder through a connector.

[0010] Furthermore, the third connecting hole is an arc-shaped slot, which corresponds to the end profile of the variable inner diameter spring.

[0011] Furthermore, the clamping disc has a serrated structure on one side of the clamping spring-woven mesh cylinder.

[0012] Furthermore, the outer edge of the end of the clamp is an arc-shaped outward-expanding structure.

[0013] Furthermore, a number of cylindrical protruding positioning posts are provided circumferentially on the outer side of the central ring, and the end of the variable inner diameter spring is nested on the outer side of the cylindrical protruding positioning posts.

[0014] Furthermore, the variable inner diameter spring includes a first end portion, a middle portion, and a second end portion, wherein the minimum inner diameter of the spring in the first end portion and the second end portion is D. min The maximum inner diameter of the middle part is D. max The inner diameter of the variable-diameter spring wire is d, and the reserved assembly clearance is δ. min D max The relationship between d and δ is: D max– D min ≥ 2d + δ The reserved assembly clearance δ is 0.2d ~ 0.5d; The pitch of the variable inner diameter spring is p, where p ≥ 2.2d and 0.5D. a ≥ p ≥ 1.5 D a D a The average inner diameter of the variable inner diameter spring.

[0015] Furthermore, when the first or second end of the variable inner diameter spring is tightened, the spring braided mesh cylinder has a maximum diameter D. wmax The maximum permissible outer diameter of the central ring is less than or equal to D. wmax When the middle portions of the variable inner diameter spring are in close contact, the spring braided mesh cylinder has a minimum diameter D. wmin The maximum permissible outer diameter of the central ring is greater than or equal to D. wmin .

[0016] This invention also provides a method for forming a wheel suitable for a lunar environment. The four clamping discs in the two rim structures are a first outer clamping disc, a first inner clamping disc, a second inner clamping disc, and a second outer clamping disc. The two central rings in the two rim structures are a first central ring and a second central ring. The forming method includes the following steps: Step 1: Use multiple mounting screws to connect the first outer clamp, the first central ring, the first inner clamp, the transmission plate, the second inner clamp, the second central ring, and the second outer clamp in sequence. The multiple mounting screws are evenly distributed around the circumference. Nuts are fitted at both ends of the mounting screws to connect the first outer clamp and the first central ring, and to connect the second outer clamp and the second central ring. Step 2: Place one end of the spring braided mesh tube on the inner side of the first outer clamp along the axial direction and the outer side of the first central ring along the radial direction, and place the other end of the spring braided mesh tube on the inner side of the second outer clamp along the axial direction and the outer side of the second central ring along the radial direction. Simultaneously twist the nuts at both ends of the mounting screw so that the combination of the first outer clamp and the first central ring and the combination of the second outer clamp and the second central ring approach each other along the axial direction. During the process of approaching each other, the spring braided mesh tube is evenly spread out along the radial direction. Step 3: After the spring-braided mesh cylinder is stretched to the target diameter, move the first inner clamping plate and the second inner clamping plate axially so that the first inner clamping plate and the second inner clamping plate contact the first central ring and the second central ring respectively. Connect the first outer clamping plate, the first central ring and the first inner clamping plate. Connect the second inner clamping plate, the second central ring and the second outer clamping plate. Use a connector to connect the spring-braided mesh cylinder to the clamping plate. Step 4: Connect the drive disc and the two wheel flange structures with fasteners, keep the spring braided mesh cylinder in an open state, remove all the mounting screws and replace the mounting screw positions with fasteners.

[0017] Compared with existing technologies, the advantages of this invention are as follows: This invention adopts a sandwich-type flange clamping structure in the overall wheel structure, installing the spring braided mesh cylinder within the clamping space formed by the two side clamping plates and the central ring, and utilizing multiple sets of connecting holes on the clamping plates to achieve stable fixing of the spring end in the radial, circumferential, and axial directions. This method results in a larger force-bearing area at the spring end and more uniform force distribution, effectively avoiding the localized stress concentration problems caused by point fixing or insufficient clamping stiffness in existing technologies. Simultaneously, the natural clamping surface formed by the clamping plate diameter being larger than the central ring diameter, along with the preferential design of arc-shaped slots and serrated structures, further restricts the radial and circumferential movement of the spring braided mesh during rolling, significantly improving the rolling stability of the tire and the overall structural reliability, fundamentally solving the technical bottleneck of uneven force distribution and easy fatigue damage in existing structures.

[0018] The spring-braided mesh cylinder of this invention employs a structure where springs with varying inner diameters are woven into a mesh cylinder. The varying inner diameter springs have a gradually changing shape, with smaller inner diameters at both ends and a larger inner diameter in the middle, forming a gradient mechanical structure that is rigid inside and flexible outside. This design not only optimizes pressure distribution, allowing the smaller inner diameter area near the wheel hub to provide higher rigidity to withstand larger initial pressure, and the larger inner diameter area further away from the wheel hub to provide greater elasticity to improve shock absorption, but also avoids assembly interference problems that may be caused by excessively tight contact of springs near the rim. Compared to spring-braided mesh cylinders with uniform inner diameters, the spring-braided mesh cylinder structure of this invention is lighter in weight with the same number of springs, or has higher load-bearing and buffering capacity with the same weight. Simultaneously, the multi-path force flow formed by the spring-braided mesh cylinder allows local impacts to naturally diffuse to multiple spring units, significantly reducing local stress peaks, improving the fatigue resistance and overall stability of the wheel, and effectively addressing the problems of insufficient overall mechanical coupling and local instability in existing structures.

[0019] The wheel forming method of this invention proposes a method to uniformly expand the mesh cylinder by adjusting the distance between the two clamping plates. This forming method utilizes a lead screw to apply symmetrical force, causing the spring-woven mesh cylinder to be expanded to the target diameter in the natural radial direction. This avoids the irreversible bending or permanent damage to the spring that may occur when the entire mesh cylinder is flipped and fitted onto the rim in the prior art, thus protecting the spring's hyperelastic recovery capability and improving assembly reliability. Furthermore, by controlling the flange spacing, the tire carcass thickness and preload can be precisely controlled, making the forming process parameterized and ensuring the consistency of the mechanical properties of each tire. This forming method supports obtaining tire carcasses of different thicknesses by adjusting the flange spacing, eliminating the need to redesign rims for different tire sizes, improving process versatility and economy, and solving the problems of difficult operation and easy damage to the springs in the existing assembly process.

[0020] This invention successfully solves key problems in the prior art, such as uneven stress distribution in tire structures, localized stress concentration, susceptibility to damage during assembly, and insufficient overall mechanical coupling. It achieves a wheel suitable for the lunar environment that simultaneously possesses high stability, strong cushioning capacity, long lifespan, high reliability, and excellent manufacturability, providing a reliable walking support solution for mobile equipment in extreme environments such as manned lunar rovers. Rolling obstacle crossing tests verified that the tire possesses excellent cushioning and energy absorption capacity, deformation recovery, and good scalability. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of a three-dimensional wheel structure suitable for the lunar environment according to the present invention; Figure 2 This is a schematic diagram of the main view of the wheel hub structure described in this invention; Figure 3 This is a schematic diagram of the wheel hub side view structure described in this invention; Figure 4 This is a schematic diagram of the three-dimensional structure of the wheel hub described in this invention; Figure 5 This is a schematic diagram of the variable inner diameter spring winding structure described in this invention; Figure 6 This is a schematic diagram of the main view of the clamping disc structure described in this invention; Figure 7 This is a top view schematic diagram of the clamp structure described in this invention; Figure 8 This is a schematic diagram of the clamping disc structure with arc-shaped slots according to the present invention; Figure 9 This is a schematic diagram of the clamping disc structure with a serrated structure described in this invention; Figure 10 This is a schematic diagram of the clamping disc structure with an arc-shaped outward expansion structure according to the present invention; Figure 11 This is a schematic diagram of the central ring main view structure described in this invention; Figure 12 This is a top view schematic diagram of the central ring structure described in this invention; Figure 13 This is a schematic diagram of the central ring structure with cylindrical protruding positioning pins according to the present invention; Figure 14 This is a schematic diagram of a wheel forming method suitable for the lunar environment according to the present invention. Figure 1 ; Figure 15 This is a schematic diagram of a wheel forming method suitable for the lunar environment according to the present invention. Figure 2 ; Figure 16 This is a schematic diagram of a wheel forming method suitable for the lunar environment according to the present invention. Figure 3 ; Figure 17 This is a schematic diagram of a wheel rolling obstacle crossing test suitable for lunar environments under room temperature conditions, as described in this invention. In the diagram, a1 and a2 are the wheel states before crossing the obstacle, b1 and b2 are the wheel states when crossing the obstacle, and c1 and c2 are the wheel states after crossing the obstacle.

[0022] In the picture: 1: Spring-woven mesh cylinder; 2: Hub; 3: Clamping disc; 4: Center ring; 5: Transmission disc; 6: First fastener; 7: Second fastener; 8: Third fastener; 9: First connecting hole; 10: Second connecting hole; 11: Third connecting hole; 12: Groove; 13: Mounting screw; 14: Nut; 3-1: First outer clamping disc; 3-2: First inner clamping disc; 3-3: Second inner clamping disc; 3-4: Second outer clamping disc; 4-1: First center ring; 4-2: Second center ring. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0024] See Figure 1-17This embodiment describes a wheel suitable for a lunar environment, comprising a spring-woven mesh cylinder 1 and a hub 2. The spring-woven mesh cylinder 1 is formed by multiple variable-diameter springs spirally wound together. The variable-diameter springs are made of shape memory alloy and have a structure with a smaller inner diameter at both ends and a larger inner diameter in the middle. The hub 2 includes a rim structure and a drive disc 5. Two rim structures are symmetrically connected to both sides of the drive disc 5 by fasteners. The rim structure includes a clamping plate 3 and a central ring 4. Two clamping plates 3 are respectively connected to both sides of the central ring 4. The end of the spring-woven mesh cylinder 1 is installed on the outside of the central ring 4. The two ends of the spring-woven mesh cylinder 1 are clamped by the two clamping plates 3. The end of the spring-woven mesh cylinder 1 is connected to the clamping plates 3 by a connector.

[0025] The wheel described in this embodiment employs a sandwich-type rim clamping structure with a spring-woven mesh cylinder 1 featuring gradually changing inner diameter and stiffness. Precise forming is achieved by adjusting the rim spacing. By installing the spring-woven mesh cylinder 1 within the clamping space formed by the two side clamping plates 3 and the central ring 4, stable fixing of the spring in both radial and circumferential directions is achieved, effectively avoiding stress concentration, ensuring uniform force distribution on the spring, and improving the fatigue resistance of the overall structure. The design of a gradually changing inner diameter along the radial direction gives the wheel high load-bearing capacity, strong cushioning, and lightweight characteristics. Adjusting the rim spacing controls the tire thickness and preload, making the wheel forming process more controllable and damage-free, suitable for different specifications and working conditions. This achieves a spring-woven wheel structure that simultaneously satisfies high load capacity, high stability, strong cushioning performance, long life, and manufacturability, providing a reliable walking support solution for mobile equipment in extreme environments such as manned lunar rovers.

[0026] like Figure 1-4 As shown, the spring braided mesh cylinder 1 is installed outside the central ring 4 and clamped by two side clamping plates 3. The diameter of the clamping plates 3 is larger than the diameter of the central ring 4, thus forming a natural clamping surface, which makes the end of the spring braided mesh cylinder 1 uniformly compressed, improving the overall stability of the end of the spring braided mesh cylinder 1. This design makes the force-bearing area of ​​the end of the spring braided mesh cylinder 1 larger and the force more uniform, and simultaneously limits the circumferential, radial and axial directions, improving the rolling stability of the tire body.

[0027] The two clamping discs 3 are connected to both sides of the central ring 4 by the first fastener 6, the two wheel rim structures are symmetrically connected to both sides of the transmission disc 5 by the second fastener 7, and the two wheel rim structures are connected by the third fastener 8. The first fastener 6, the second fastener 7 and the third fastener 8 are lead screws or bolts.

[0028] like Figure 6 and 7As shown, the basic structure of the clamp 3 is annular. The clamp 3 is provided with a first connecting hole 9, a second connecting hole 10 and a third connecting hole 11 in a radial direction from the inside to the outside. Multiple first connecting holes 9 and second connecting holes 10 are evenly distributed in the circumferential direction. One or more third connecting holes 11 are grouped together. Multiple groups of third connecting holes 11 are evenly distributed in the circumferential direction. The size of the clamp 3 can be adjusted proportionally according to actual needs. The first connecting hole 9 is located on the innermost side of the clamp 3. The second fastener 7 and the third fastener 8 are connected within the first connecting hole 9. The first connecting hole 9 is used to connect the two wheel rims to the transmission disc 5 via the fasteners. In this embodiment, 12 first connecting holes 9 are provided on the clamp 3, with adjacent holes spaced 30° apart. The number of first connecting holes 9 can be adjusted reasonably according to actual conditions.

[0029] The second connecting hole 10 is located in the middle of the clamping plate 3. The first fastener 6 is connected inside the second connecting hole 10. The second connecting hole 10 is used for docking and fixing between the clamping plate 3 and the central ring 4. In this embodiment, six second connecting holes 10 are provided on the clamping plate 3, with adjacent holes spaced 60° apart. The number of second connecting holes 10 can be adjusted reasonably according to the actual situation.

[0030] The third connecting hole 11 is located on the outermost side of the clamping plate 3, and is connected to the spring braided mesh cylinder 1 via a connector. The third connecting hole 11 is used to reliably fix the end of the spring braided mesh cylinder 1 to the rim. In this embodiment, 24 third connecting holes 11 are provided on the clamping plate 3, with two third connecting holes 11 forming a group, for a total of 12 groups. The interval between two adjacent holes in each group is 3°, and the interval between adjacent holes in each group is 27°. The number of third connecting holes 11 in each group and the number of groups can be designed according to actual conditions.

[0031] To avoid stress concentration of the spring in the clamping area, this invention proposes several preferred clamping disc structures, which can be combined and applied in various embodiments to achieve the best results.

[0032] Preferred option 1: such as Figure 8 As shown, the third connecting hole 11 is an arc-shaped slot, which corresponds to the end profile of the variable inner diameter spring. The arc-shaped slot is designed according to the spring surface profile to simulate the spring profile, increase the contact area, and effectively reduce fatigue damage caused by point loads.

[0033] Preferred option 2: such as Figure 9 As shown, the clamping plate 3 has a serrated structure on one side of the clamping spring braided mesh cylinder 1. The serrated structure restricts the radial movement of the spring braided mesh cylinder 1 relative to the clamping plate 3, and at the same time restricts the circumferential movement of the spring braided mesh cylinder 1 relative to the clamping plate 3, thereby improving structural stability.

[0034] Preferred option 3: such as Figure 10As shown, the outer edge of the end of the clamp 3 has an arc-shaped outward expansion structure. The arc-shaped outward expansion structure allows the wheel to fit snugly against the spring braided mesh cylinder 1 when it rolls, improving the follow-up contact of the spring, avoiding local overload of the tire body when it is deformed by impact, and improving service life and stability.

[0035] Preferred Option 4: Contact Surface Strengthening Treatment. This includes micro-arc oxidation, surface hardening, etc., to improve wear resistance and extend the overall service life of the tire.

[0036] like Figure 11 and 12 As shown, the basic structure of the central ring 4 is a circular ring structure, with a second connecting hole 10 at the same position as the clamping plate 3, for alignment and connection with the clamping plate 3. The central ring 4 has grooves 12 in areas without connecting holes for weight reduction, optimizing the overall weight while ensuring structural strength. The thickness of the central ring 4 needs to be equal to the end thickness of the spring-woven mesh cylinder 1.

[0037] To further restrict the circumferential movement of the spring-braided mesh cylinder 1 relative to the clamping plate 3 or the central ring 4, several cylindrical protruding positioning posts are arranged circumferentially on the outer side of the central ring 4, and the end of the variable inner diameter spring is nested on the outer side of the cylindrical protruding positioning posts. Figure 13 As shown, the diameter of the cylindrical protruding positioning post is slightly smaller than the inner diameter of the variable inner diameter spring. It restricts the circumferential movement of the spring braided cylinder by embedding, ensuring the springs are evenly arranged axially. This prevents the springs from moving in unison, improves the consistency of force distribution on the tire body, and enhances high-speed driving stability.

[0038] like Figure 5 As shown, the tire body of the wheel is composed of multiple variable inner diameter springs connected to each other by spiral winding, forming a spring braided mesh 1 with a specific diameter range. The middle section of the variable inner diameter spring provides greater displacement capacity, while the two end sections provide higher support stiffness, creating a gradient mechanical structure with inner stiffness and outer flexibility. Compared to independent corrugated wire or fixed inner diameter spring mesh structures, the spring braided mesh 1 of this invention forms a multi-path force flow during load transmission, allowing local impacts to naturally diffuse to multiple variable inner diameter spring units, thereby significantly reducing local stress peaks and improving fatigue performance and overall stability. Furthermore, the portion of the constant inner diameter spring near both ends contributes less to load bearing but still has a large inner diameter, wasting limited load weight. Replacing it with a gradually changing inner diameter spring with smaller inner diameters at both ends and a larger inner diameter in the middle can effectively solve this problem, resulting in a lighter wheel weight with the same number of springs. In addition, the smaller inner diameter of the springs at both ends increases the maximum number of springs in the spring braided mesh 1, improving the tire's load bearing and cushioning capacity, achieving higher load bearing and cushioning capacity for the same mass compared to a constant inner diameter spring braided mesh.

[0039] The variable inner diameter spring includes a first end portion, a middle portion, and a second end portion, wherein the minimum inner diameter of the first end portion and the second end portion is D. min The maximum inner diameter of the middle part is D. max The inner diameter of the variable-diameter spring wire is d. Considering factors such as machining errors and spring elastic deformation, an assembly clearance of δ is reserved for D. min D max The relationship between d and δ is: D max – D min ≥ 2d + δ The assembly clearance δ is typically 0.2d ~ 0.5d; The dimensional constraints of the variable inner diameter spring pitch p are also required to ensure geometric assembly and stress constraints. If p is too large, the spring braided mesh 1 will be too sparse, leading to discontinuous tire carcass support, local stress concentration, insufficient contact points between adjacent springs, and poor overall mesh coupling; the tread is also prone to large local deformation under load. If p is too small, it will cause assembly interference of the spring braided mesh 1. Therefore, considering the above factors, the dimensional requirements for the pitch p are: p ≥ 2.2 d and 0.5 D. a ≥ p ≥ 1.5 D a D a The average inner diameter of the variable inner diameter spring.

[0040] When finalizing the diameter of the center ring 4, the diameter characteristics of the spring braided mesh tube 1 must be strictly referenced: Diameter upper limit constraint: When the first or second end of the variable inner diameter spring is tightened, the spring braided mesh cylinder 1 has a maximum diameter D. wmax D of spring braided mesh tube 1 wmax This fundamentally determines the maximum permissible outer diameter of the center ring 4. The maximum permissible outer diameter of the center ring 4 is less than or equal to D. wmax .

[0041] Diameter lower limit constraint: When the middle portions of the variable inner diameter spring are in close contact, the spring braided mesh cylinder 1 has a minimum diameter D. wmin The maximum permissible outer diameter of the central ring 4 is greater than or equal to D. wmin .

[0042] like Figures 14-16 As shown, a method for forming a wheel suitable for a lunar environment is described. The four clamping discs 3 in the two wheel rim structures are a first outer clamping disc 3-1, a first inner clamping disc 3-2, a second inner clamping disc 3-3, and a second outer clamping disc 3-4. The two central rings 4 in the two wheel rim structures are a first central ring 4-1 and a second central ring 4-2. The forming method includes the following steps: Step 1: Using three relatively long mounting screws 13, connect the first outer clamp 3-1, the first central ring 4-1, the first inner clamp 3-2, the transmission disc 5, the second inner clamp 3-3, the second central ring 4-2, and the second outer clamp 3-4 in sequence. The three mounting screws 13 pass through the first connecting hole 9 and are evenly distributed circumferentially. Nuts 14 are fitted at both ends of the mounting screws 13. Use bolts or any possible connection method to connect the first outer clamp 3-1 and the first central ring 4-1 through the second connecting hole 10, and connect the second outer clamp 3-4 and the second central ring 4-2. Step 2: Place one end of the spring braided mesh tube 1 on the inner side of the first outer clamp 3-1 along the axial direction and the outer side of the first central ring 4-1 along the radial direction, and place the other end of the spring braided mesh tube 1 on the inner side of the second outer clamp 3-4 along the axial direction and the outer side of the second central ring 4-2 along the radial direction. Simultaneously twist the nuts 14 at both ends of the screw 13 to make the combination of the first outer clamp 3-1 and the first central ring 4-1 and the combination of the second outer clamp 3-4 and the second central ring 4-2 approach each other along the axial direction. During the process of approaching each other, the spring braided mesh tube 1 is evenly spread open along the radial direction. Step 3: After the spring braided mesh cylinder 1 is expanded to the target diameter, the first inner clamping plate 3-2 and the second inner clamping plate 3-3 are moved axially so that the first inner clamping plate 3-2 and the second inner clamping plate 3-3 contact the first central ring 4-1 and the second central ring 4-2 respectively. The first outer clamping plate 3-1, the first central ring 4-1 and the first inner clamping plate 3-2 are connected through the second connecting hole 10 by bolts or other possible means. The second inner clamping plate 3-3, the second central ring 4-2 and the second outer clamping plate 3-4 are connected. The spring braided mesh cylinder 1 is connected to the clamping plate 3 using a connector; the connector includes, but is not limited to, bolts, screws, cable ties, etc.

[0043] Step 4: Use shorter fasteners to pass through the remaining first connection holes 9 to connect the drive disc 5 and the two wheel rim structures, keeping the spring braided mesh cylinder 1 in an open state. Then remove the three longer mounting screws 13 used for opening and replace them with shorter fasteners.

[0044] like Figure 17As shown, to verify the core function of the wheel, a φ120 cm tire was used as an example to demonstrate the wheel's rolling obstacle-crossing test on a flat road surface and a simulated obstacle road surface at room temperature. The test results show that after crushing an obstacle and undergoing significant deformation, the wheel described in this invention can achieve complete or near-complete shape recovery thanks to the inherent superelastic effect of its NiTi shape memory alloy material. This phenomenon directly confirms that the wheel described in this invention possesses excellent buffering and energy absorption capabilities and deformation recovery, fundamentally solving the technical problems of traditional metal wheels being prone to plastic deformation and failure, and rubber wheels experiencing elasticity degradation due to environmental aging, ensuring its long-term reliability in the complex lunar environment.

[0045] The specific embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A wheel suitable for the lunar environment, characterized in that: It includes a spring-braided mesh cylinder (1) and a hub (2). The spring-braided mesh cylinder (1) is formed by multiple variable inner diameter springs spirally wound together. The variable inner diameter springs are made of shape memory alloy and have a structure with small inner diameters at both ends and large inner diameters in the middle. The hub (2) includes a rim structure and a transmission disc (5). The two rim structures are symmetrically connected to both sides of the transmission disc (5) by fasteners. The rim structure includes a clamping disc (3) and a central ring (4). The two clamping discs (3) are respectively connected to both sides of the central ring (4). The end of the spring-braided mesh cylinder (1) is installed on the outside of the central ring (4). The ends of the spring-braided mesh cylinder (1) are clamped by the two clamping discs (3) on both sides. The end of the spring-braided mesh cylinder (1) is connected to the clamping disc (3) through a connector.

2. A wheel suitable for the lunar environment according to claim 1, characterized in that: The two clamps (3) are connected to the two sides of the central ring (4) by the first fastener (6), the two wheel rim structures are symmetrically connected to the two sides of the transmission disc (5) by the second fastener (7), and the two wheel rim structures are connected by the third fastener (8). The first fastener (6), the second fastener (7) and the third fastener (8) are lead screws or bolts.

3. A wheel suitable for the lunar environment according to claim 2, characterized in that: The clamp (3) is provided with a first connecting hole (9), a second connecting hole (10) and a third connecting hole (11) in a radial direction from the inside to the outside. Multiple first connecting holes (9) and second connecting holes (10) are evenly distributed in the circumferential direction. One or more third connecting holes (11) are grouped together. Multiple groups of third connecting holes (11) are evenly distributed in the circumferential direction. The first connecting hole (9) is connected to the second fastener (7) and the third fastener (8). The second connecting hole (10) is connected to the first fastener (6). The third connecting hole (11) is connected to the spring braided mesh cylinder (1) through a connector.

4. A wheel suitable for the lunar environment according to claim 3, characterized in that: The third connecting hole (11) is an arc-shaped slot, which corresponds to the end profile of the variable inner diameter spring.

5. A wheel suitable for the lunar environment according to claim 1, characterized in that: The clamping plate (3) has a serrated structure on one side of the clamping spring braided mesh cylinder (1).

6. A wheel suitable for the lunar environment according to claim 1, characterized in that: The outer edge of the end of the clamp (3) is an arc-shaped outward expansion structure.

7. A wheel suitable for the lunar environment according to claim 1, characterized in that: The outer side of the central ring (4) is provided with several cylindrical protruding positioning posts along the circumferential direction, and the end of the variable inner diameter spring is nested on the outer side of the cylindrical protruding positioning posts.

8. A wheel suitable for the lunar environment according to claim 1, characterized in that: The variable inner diameter spring includes a first end portion, a middle portion, and a second end portion, wherein the minimum inner diameter of the first end portion and the second end portion is D. min The maximum inner diameter of the middle part is D. max The inner diameter of the variable-diameter spring wire is d, and the reserved assembly clearance is δ. min D max The relationship between d and δ is: D max – D min ≥ 2d + δ The reserved assembly clearance δ is 0.2d ~ 0.5d; The pitch of the variable inner diameter spring is p, where p ≥ 2.2d and 0.5D. a ≥ p ≥ 1.5 D a D a The average inner diameter of the variable inner diameter spring.

9. A wheel suitable for the lunar environment according to claim 8, characterized in that: When the first or second end of the variable inner diameter spring is tightened, the spring braided mesh tube (1) has a maximum diameter D. wmax The maximum permissible outer diameter of the central ring (4) is less than or equal to D. wmax When the middle portions of the variable inner diameter spring are in close contact, the spring braided mesh tube (1) has a minimum diameter D. wmin The maximum permissible outer diameter of the central ring (4) is greater than or equal to D. wmin .

10. A method for forming a wheel suitable for a lunar environment as described in any one of claims 1-9, wherein the four clamping discs (3) in the two rim structures are respectively a first outer clamping disc (3-1), a first inner clamping disc (3-2), a second inner clamping disc (3-3), and a second outer clamping disc (3-4), and the two central rings (4) in the two rim structures are respectively a first central ring (4-1) and a second central ring (4-2), characterized in that: The molding method includes the following steps: Step 1: Use multiple mounting screws (13) to connect the first outer clamp (3-1), the first central ring (4-1), the first inner clamp (3-2), the transmission plate (5), the second inner clamp (3-3), the second central ring (4-2), and the second outer clamp (3-4) in sequence. The multiple mounting screws (13) are evenly distributed around the circumference. Nuts (14) are fitted at both ends of the mounting screws (13). Connect the first outer clamp (3-1) and the first central ring (4-1), and connect the second outer clamp (3-4) and the second central ring (4-2). Step 2: Place one end of the spring braided mesh tube (1) on the inner side of the first outer clamp (3-1) along the axial direction and the outer side of the first central ring (4-1) along the radial direction, and place the other end of the spring braided mesh tube (1) on the inner side of the second outer clamp (3-4) along the axial direction and the outer side of the second central ring (4-2) along the radial direction. Simultaneously twist the nuts (14) at both ends of the screw (13) so that the combination of the first outer clamp (3-1) and the first central ring (4-1) and the combination of the second outer clamp (3-4) and the second central ring (4-2) approach each other along the axial direction. During the process of approaching each other, the spring braided mesh tube (1) is evenly spread open along the radial direction. Step 3: After the spring braided mesh cylinder (1) is expanded to the target diameter, the first inner clamping plate (3-2) and the second inner clamping plate (3-3) are moved axially so that the first inner clamping plate (3-2) and the second inner clamping plate (3-3) contact the first central ring (4-1) and the second central ring (4-2) respectively, connect the first outer clamping plate (3-1), the first central ring (4-1) and the first inner clamping plate (3-2), connect the second inner clamping plate (3-3), the second central ring (4-2) and the second outer clamping plate (3-4), and connect the spring braided mesh cylinder (1) to the clamping plate (3) using a connector; Step 4: Connect the transmission disc (5) and the two wheel flange structures with fasteners, keep the spring braided mesh cylinder (1) in the open state, remove all the mounting screws (13) and replace the mounting screws (13) with fasteners.

Images