A deformable wheel with a non-pneumatic load support and a rotating stopper disc, suitable for lunar and Martian conditions.

Abstract

To provide a deformable wheel structure with a non-pneumatic load bearing, which can avoid alteration of a tread layer when the tread layer abuts with a stop disc.SOLUTION: A deformable wheel (2) with a non-pneumatic load bearing comprises: a hub (4) bearing at least one stop disc (20) which projects radially outwards; a tread layer (6) having an outer surface intended to be in contact with the ground, where the tread layer is able to deform under an externally applied load in order to match the surface of the ground, and has an inner surface which is able to come to press the stop disc in order to limit the deformation of the tread layer in the radial direction; and a plurality of radial reinforcements (8) linking the tread layer to the hub; where the stop disc is rotatably mounted on the hub so as to be able to be rotated when the inner surface of the tread layer comes to press the stop disc.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a deformable wheel having a non-pneumatic load support portion. More specifically, the present invention relates to a wheel having performance capabilities suitable for being equipped on a vehicle intended to travel under harsh conditions such as those encountered on the moon and Mars, which supports a load by its structural elements.

Background Art

[0002] Pneumatic wheels have load-bearing capacity, road shock absorption capacity, and power transmission capacity (acceleration capacity, stopping capacity, and direction-changing capacity), and these functions are particularly suitable for many vehicles including bicycles, motorcycles, passenger cars, and trucks. The shock absorption capacity of pneumatic tires is also useful for other applications such as carts for transporting medical devices or precision electronic materials.

[0003] There are alternatives to pneumatic wheels. For example, solid tires and spring-loaded tires can be mentioned. However, these alternatives do not have the performance advantages of pneumatic wheels. In particular, solid tires support a load depending on the compression of the portion in contact with the ground. This type of tire can be heavy and hard and does not have the shock absorption capacity of pneumatic wheels. The higher the elasticity is increased, the less the conventional non-pneumatic wheels have the load-bearing capacity or durability of pneumatic wheels.

[0004] To overcome these drawbacks, U.S. Patent No. 7,418,988 proposes a structurally supported tire including an outer annular band and a plurality of spokes, the plurality of spokes extending in a direction crossing from the annular band to the hub of the wheel and radially inward, and intended to transmit the load force between the annular band and the hub by tension.

[0005] The structurally supported wheel of the above invention does not contain a cavity intended to contain compressed air, and therefore does not require sealing at the rim of the wheel to maintain internal air pressure. Thus, this structurally supported wheel does not require a tire in the conventional sense.

[0006] The spokes of a wheel act to transmit load forces between the wheel and the ring when under tension, and can support the mass of a vehicle in particular. The supporting force is generated by the tension in the spokes that are not connected to the part of the ring that contacts the ground. The spokes also transmit the forces required for acceleration, stopping, and turning.

[0007] Regardless of the alternatives known from the prior art for manufacturing non-pneumatic wheels, these alternatives generally do not provide complete satisfaction, especially when intended for operation in harsh conditions such as those encountered on the Moon and Mars. In fact, in such situations, the wheel needs to be able to deform significantly while generating low, uniform ground pressure so that the vehicle can continue to move on loose ground such as that encountered on the Moon and Mars when passing over obstacles.

[0008] European Patent Application No. 22192685, filed by the applicant on 29 August 2022, discloses a wheel that can satisfy these requirements, in particular by the presence of an annular laminate, comprising a plurality of concentric ferrules assembled via intervening layers, each intervening layer being composed of a material whose Young's modulus is 600,000 to 1,000 times that of the ferrule's Young's modulus, and is formed from, for example, an elastomer material. Under an externally applied load, a portion of the laminate in contact with the ground deforms into a shape that conforms to the ground surface, rather than being substantially circular, while maintaining a substantially constant ferrule length. As a result, the wheel according to this patent application can generate a constant low contact pressure with the ground. Thus, a vehicle equipped with such a wheel can continue to move even on loose ground (such as sandy ground) like the ground encountered on the Moon and Mars (i.e., the vehicle does not sink into the sand).

[0009] The wheel described in this patent application also comprises rigid discs of the hub projecting radially outward to form a stopper that can restrict the movement of the wheel's tread layer. More specifically, depending on the size of the obstacle the wheel passes over, the inner surface of the laminated strip can contact (be in contact with) these discs supported by the hub to limit the deformation the laminated strip experiences.

[0010] Furthermore, depending on the vehicle's application, it may be advantageous to be able to travel short distances at low speeds while transporting cargo, so that the inner surface of the laminated strip can permanently contact the disc supported by the hub, even without obstacles.

[0011] However, in these situations, a significant difference in tangential velocity between the tread layer and the stopper disc can cause the tread layer to slip on the disc, potentially damaging the stopper and significantly altering the inner surface of the tread layer. This threatens the integrity of the wheel. [Overview of the project] [Problems that the invention aims to solve]

[0012] Therefore, the main objective of the present invention is to overcome such drawbacks by proposing a deformable wheel structure having a non-pneumatic load support section, wherein the deformable wheel structure includes a device that can prevent deterioration of the tread layer when the tread layer comes into contact with a stopper disc. [Means for solving the problem]

[0013] According to the present invention, this objective is achieved by a deformable wheel having a non-pneumatic load support, intended for use on vehicles operating in harsh conditions such as those encountered on the Moon and Mars, and the wheel is A hub supporting at least one stopper disc that protrudes radially outward, An annular tread layer positioned around a hub and having an outer surface intended to contact the ground, which is deformable under externally applied loads to conform to the ground surface, and whose inner surface is capable of pressing against a stopper disc to limit the radial deformation of the tread layer, Multiple radial reinforcing parts that connect the tread layer to the hub, Equipped with, Here, according to the present invention, The stopper disc is rotatably mounted on the hub so that it can rotate when the inner surface of the tread layer presses against the stopper disc.

[0014] The wheel according to the present invention is characterized in that a stopper disc is rotatably mounted on the hub, thereby allowing the stopper disc to "rotate" when the tread layer comes into contact with the stopper disc, even with differences in speed. Thus, the system appears to be a ball bearing type device that acts only when the tread layer is in contact with the stopper. This rotation of the stopper disc significantly reduces the risk of deterioration of the tread layer, and consequently, the wheel.

[0015] The stopper disc is preferably attached to the outer surface of the hub by roller bearings.

[0016] In this case, the roller bearing may comprise a plurality of cylindrical rollers mounted between the outer surface of the hub and the inner annular band of the stopper disc.

[0017] The stopper disc may include an outer annular band attached around the inner band by multiple spring connectors.

[0018] In this case, each spring connection can be formed by a deformable ring.

[0019] The deformable ring of the spring connection part is preferably composed of a coil of stainless steel strip.

[0020] Preferably, each spring connection part further includes a bush that forms a rigid stopper attached to the inside of the ring.

[0021] The cylindrical rollers are preferably regularly spaced on the outer surface of the hub around the axis of rotation of the wheel.

[0022] Preferably, the outer band of the stopper disc is covered with an outer protection part formed of leather.

[0023] The hub can support two stopper discs spaced apart from each other along the axis of rotation of the wheel.

[0024] The tread layer can be a metal shear band having a metal core, and the metal core is provided with a corrugated portion sandwiched between a ferrule and a plurality of circumferential springs that impart the ability to bend and deform to the tread layer.

[0025] Other features and advantages of the present invention will become apparent from the following description, with reference to the accompanying drawings showing exemplary embodiments thereof, which are not of any limiting nature. The drawings are as follows.

Brief Description of the Drawings

[0026] [Figure 1] FIG. 1 is a schematic front view of a wheel according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective cross-sectional view of the wheel of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view of the wheel of FIG. 1.

Modes for Carrying Out the Invention

[0027] The present invention relates to a deformable wheel having a non-pneumatic load support section, as shown in Figure 1, and the wheel is suitable for mounting on vehicles intended to travel under harsh conditions such as those encountered on the Moon and Mars.

[0028] The wheel 2 shown in Figure 1 mainly comprises a hub 4, an annular tread layer 6 having an outer surface intended to contact the ground and capable of deforming under externally applied loads to conform to the ground surface, and a plurality of radial reinforcements (metal cables 8 in Figure 1) radially connecting the hub to the tread layer.

[0029] In this embodiment, the tread layer 6 is a bent band comprising a metal core 10, and the metal core is provided with a plurality of corrugated portions 12 sandwiched between a ferrule 14 and a plurality of circumferential springs 16 that impart the ability to bend and deform to the tread layer.

[0030] More precisely, as shown in Figures 2 and 3, the corrugated portion 12 of the tread layer core 10 is formed from a metal sheet that is bent into a V-shape in the longitudinal direction (in other words, parallel to the longitudinal axis of rotation XX of the wheel 2).

[0031] It should be noted that the V-shaped tip of the metal sheet forming the corrugated portion 12 faces inward towards the wheel (in other words, towards the wheel's rotation axis (XX)) and is open toward the outside of the wheel.

[0032] Furthermore, it should be noted that each corrugated portion 12 of the tread layer core is symmetrical with respect to a plane P in the radial direction of the wheel (and passing through the V-shaped tip of the corrugated portion).

[0033] Furthermore, it should be noted that the metal sheet constituting the corrugated portion advantageously has holes 18, and the holes 18 are arranged separately along the entire length of the metal sheet in order to reduce the weight of the wheel.

[0034] In this embodiment, the ferrule 14 of the wheel tread layer 6 is formed from a metal material or a composite material (for example, having glass fibers or carbon fibers).

[0035] Finally, the wheel tread layer 6 in this embodiment includes a plurality of circumferential springs 16 that impart to the tread layer the ability to bend and deform.

[0036] As already shown, in this embodiment, the radial reinforcement portion that radially connects the wheel hub 4 to the tread layer 6 is made of a metal cable 8.

[0037] It should be noted that the radial reinforcement portion that radially connects the wheel hub 4 to the tread layer 6 can be made of a spring instead of a metal cable (this embodiment is not shown).

[0038] Similarly, in another embodiment (not shown), the tread layer is an annular laminated strip comprising a plurality of concentric ferrules assembled via intervening layers, each intervening layer being made of a material whose Young's modulus is 1 / 600,000 to 1 / 1,000 of the Young's modulus of the ferrule.

[0039] The ferrules of such laminated bands can be formed from metal or composite materials, while the intervening layers can be made from superelastic elastomers having a glass transition temperature of less than 120°C.

[0040] You can refer to European Patent Application No. 22192685, filed by the present applicant on 29 August 2022, which describes a wheel structure having such laminated tread layers.

[0041] In any embodiment, the wheel hub 4 supports at least one stopper disc 20 that projects radially outward toward the wheel.

[0042] When a large obstacle (e.g., a rock) is present on the ground surface where the wheel 2 is rotating, a portion of the tread layer 6 in contact with the ground deforms to conform to the shape of the obstacle. In such a situation, depending on the size of the obstacle, the inner surface of the tread layer may contact the outer diameter of the stopper disc 20 supported by the hub 4, in order to limit the deformation of the tread layer. Similar situations can occur during low-speed rotation and under large overloads.

[0043] According to the present invention, the stopper disc 20 is rotatably mounted on the hub 4 so that it can rotate around the XX axis of the wheel when the inner surface of the tread layer 6 comes into contact with the stopper disc.

[0044] More precisely, in the embodiments shown in Figures 1-3, the stopper disc 20 is attached to the outer surface of the hub 4 by a roller bearing 22.

[0045] The roller bearing 22 preferably comprises a plurality of cylindrical rollers 24 mounted between the outer surface of the hub 4 and the inner annular band 26 of the stopper disc. The cylindrical rollers 24 are regularly spaced and arranged around the entire circumference of the wheel's rotation (XX) axis.

[0046] Thus, when the inner surface of the tread layer 6 comes into contact with the outer diameter of the stopper disc 20 (especially when the wheel rolls over a large obstacle), the stopper disc 20 can rotate around the hub regardless of the different rotational speeds between the hub and the tread layer.

[0047] In the advantageous configuration, the stopper disc 20 also includes an outer annular band 28 that is attached around the inner band 26 by a plurality of spring connectors 30.

[0048] In the embodiments shown in Figures 1-3, each spring connection is formed by a deformable ring 30, which is advantageously composed of multiple stainless steel strips (e.g., 12 strips of 0.15 mm thickness). Alternatively, these rings can be formed from a glass fiber-resin composite material.

[0049] It should be noted that the deformable ring 30 is preferably regularly divided and arranged around the entire circumference of the wheel's rotation (XX) axis.

[0050] In another advantageous configuration, each spring connection further comprises a bush 32 that forms a rigid stopper mounted inside the ring 30.

[0051] The bush 32 can be fixed to either the inner band 26 or the outer band 28 of the stopper disc. This prevents the deformable ring 30 from deforming excessively when the tread layer deforms significantly.

[0052] In yet another configuration, the outer band 28 of the stopper disc is covered with an outer protective part 34 formed from, for example, leather.

[0053] In another embodiment not shown, the wheel hub supports two stopper discs spaced apart from each other along the wheel's rotation (XX) axis.

Claims

1. A deformable wheel (2) having a non-pneumatic load support, intended for use on vehicles operating in harsh conditions such as those encountered on the Moon and Mars, A hub (4) supporting at least one stopper disc (20) that protrudes radially outward, An annular tread layer (6) positioned around the hub and having an outer surface intended to contact the ground, which is deformable under externally applied loads to conform to the ground surface, and whose inner surface is capable of pressing against the stopper disc to limit radial deformation of the tread layer, Multiple radial reinforcing portions (8) that connect the tread layer to the hub, Equipped with, The stopper disc (20) is rotatably mounted on the hub so as to be able to rotate when the inner surface of the tread layer comes into contact with the stopper disc. The stopper disc (20) is attached to the outer surface of the hub (4) by a roller bearing (22). The roller bearing (22) comprises a plurality of cylindrical rollers (24) mounted between the outer surface of the hub and the inner annular band (26) of the stopper disc (20), The stopper disc (20) includes an outer annular band (28) attached around the inner annular band (26) by a plurality of spring connection parts (30), The spring connection portion is formed by a deformable ring (30) in a wheel.

2. The deformable ring (30) of the spring connection is made of a roll of stainless steel strip. The wheel according to claim 1.

3. Each spring connection portion further includes a bush (32) that forms a hard stopper attached to the inside of the ring (30). The wheel according to claim 1.

4. The cylindrical rollers (24) are regularly spaced and arranged on the outer surface of the hub (4) around the rotation (X-X) axis of the wheel. The wheel according to claim 1.

5. The outer annular band (28) of the stopper disc (20) is covered with an outer protective portion (34) formed from leather. The wheel according to claim 1.

6. The hub (4) supports two stopper discs spaced apart from each other along the rotation (X-X) axis of the wheel. The wheel according to claim 1.

7. The tread layer (6) is a bent band comprising a metal core (10), and the metal core is provided with a corrugated portion (12) sandwiched between an annular band (14) and a plurality of circumferential springs (16) that impart the ability to bend and deform to the tread layer. The wheel according to claim 1.

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