Patent Application
20200385113
The present invention relates generally to a flying vehicle having vehicle tires used as rotors, and more particularly, to an autonomous flying vehicle with a non-pneumatic wheel which acts as a rotor.
As the challenges of urban transport and congestion continue to grow, mobility companies are searching for new solutions. Increasingly, they are looking to the sky for the answer. The technology behind flying cars is developing at a huge pace and they now seem closer than ever. Specially designed so that they can tilt and become rotors, AERO tires would be the foundation of a new, environmentally-friendly, on-demand, congestion-free mobility solution. The concept's non-pneumatic structure supports the weight of the vehicle for worry-free mobility on road while becoming the fins of the rotor Thus an improved flying machine which utilizes a non-pneumatic wheel as rotor is desired, and that has all the features of the pneumatic tires without the drawback of the need for air inflation is desired.
The following terms are defined as follows for this description.
“Equatorial plane” means a plane perpendicular to the axis of rotation of the tire passing through the centerline of the tire.
“Meridian plane” means a plane parallel to the axis of rotation of the tire and extending radially outward from said axis.
“Hysteresis” means the dynamic loss tangent measured at 10 percent dynamic shear strain and at 25° C.
An autonomous flying machine 100 of the present invention is shown in the enclosed figures. The autonomous flying machine 100 includes a cabin 110 having a door 112 for housing one or more passengers. The autonomous flying machine 100 includes a flight computer control system 130 which can autonomously fly the aircraft without a pilot. The autonomous flying machine 100 includes at least three non-pneumatic wheels, which function as load bearing wheels allowing the flying machine to be driven on the road when on the ground. The non-pneumatic wheels also function as rotors, and generate a lifting force when rotated, which is sufficient to propel the flying machine off of the ground. The nonpneumatic wheels are mounted on support arms 200, which rotate the nonpneumnatic wheels at a desired angle, typically ninety degrees or more, as shown in
The nonpneumatic wheel of the present invention includes a radially outer ground engaging tread, a shear band, and one or more reinforcement layers. The non-pneumatic tire of the present invention is designed to be a top loaded structure, so that the shear band and the reinforcement layer efficiently carries the load. The shear band and the reinforcement layer are designed so that the stiffness of the shear band is directly related to the spring rate of the tire. The reinforcement layer is designed to be a stiff structure that buckles or deforms in the tire footprint and does not compress or carry a compressive load. This allows the rest of structure not in the footprint area the ability to carry the load, resulting in a very load-efficient structure. It is desired to minimize this load for the reason above and to allow the shear band to bend to overcome road obstacles. The approximate load distribution is such that approximately 95% of the load is carried by the shear band and the upper radial portion of the reinforcement layer, so that the lower portion of the reinforcement structure undergoing compression carries virtually zero of the load, and preferably less than 10%.
The tread portion may be a conventional tread as desired and may include grooves or a plurality of longitudinally oriented tread grooves forming essentially longitudinal tread ribs there between. Ribs may be further divided transversely or longitudinally to form a tread pattern adapted to the usage requirements of the particular vehicle application. Tread grooves may have any depth consistent with the intended use of the tire. The tire tread may include elements such as ribs, blocks, lugs, grooves, and sipes as desired to improve the performance of the tire in various conditions.
The shear band is preferably annular. The shear band is located radially inward of the tire tread. The shear band includes a first and second reinforced elastomer layer. In a first embodiment of a shear band, the shear band is comprised of two inextensible reinforcement layers arranged in parallel and separated by a shear matrix of elastomer. Each inextensible layer may be formed of parallel inextensible reinforcement cords, embedded in an elastomeric coating. The reinforcement cords may be steel, aramid, nylon, polyester or other inextensible structure. The shear band may further optionally include a third reinforced elastomer layer (not shown) located between the first and second reinforced elastomer layers.
It is additionally preferred that the outer lateral ends of the shear band be radiused in order to control the buckled shape of the sidewall and to reduce flexural stresses.
In the first reinforced elastomer layer, the reinforcement cords are oriented at an angle Φ in the range of 0 to about +/−10 degrees relative to the tire equatorial plane. In the second reinforced elastomer layer, the reinforcement cords are oriented at an angle φ in the range of 0 to about +/−10 degrees relative to the tire equatorial plane. Preferably, the angle Φ of the first layer is in the opposite direction of the angle φ of the reinforcement cords in the second layer. That is, an angle +Φ in the first reinforced elastomeric layer and an angle −φ in the second reinforced elastomeric layer.
The shear matrix may have a radial thickness in the range of about 0.10 inches to about 0.2 inches, more preferably about 0.15 inches. The shear matrix is preferably formed of an elastomer material having a shear modulus Gm in the range of 15 to 80 MPa, and more preferably in the range of 40 to 60 MPA.
The shear band has a shear stiffness GA. The shear stiffness GA may be determined by measuring the deflection on a representative test specimen taken from the shear band. The upper surface of the test specimen is subjected to a lateral force F as shown below. The test specimen is a representative sample taken from the shear matrix material, having the same radial thickness.
The shear stiffness GA is then calculated from the following equation:
GA=F*L/ΔX
The shear band has a bending stiffness EI. The bending stiffness EI may be determined from beam mechanics using the three-point bending test subjected to a test specimen representative of the shear band. It represents the case of a beam resting on two roller supports and subjected to a concentrated load applied in the middle of the beam. The bending stiffness EI is determined from the following equation: EI=PL3/48*ΔX, where P is the load, L is the beam length, and ΔX is the deflection.
It is desirable to maximize the bending stiffness of the shear band EI and minimize the shear band stiffness GA. The acceptable ratio of GA/EI would be between 0.01 and 20, with a preferred range between 0.01 and 5. EA is the extensible stiffness of the shear band, and it is determined experimentally by applying a tensile force and measuring the change in length. The ratio of the EA to EI of the shear band is acceptable in the range of 0.02 to 100, with a preferred range of 1 to 50. The shear band preferably can withstand a maximum shear strain in the range of 15-30%.
The shear band has a spring rate k that may be determined experimentally by exerting a downward force on a horizontal plate at the top of the shear band and measuring the amount of deflection. The spring rate k is determined from the slope of the Force versus deflection curve.
The non-pneumatic tire has an overall spring rate kt that is determined experimentally. The non-pneumatic tire is mounted upon a rim, and a load is applied to the center of the tire through the rim. The spring rate kt is determined from the slope of the Force versus deflection curve. The spring rate kt is preferably in the range of 500 to 0 for small low speed vehicles such as lawn mowers.
The invention is not limited to the shear band structure disclosed herein, and may comprise any structure which has a GA/EI in the range of 0.01 to 20, or a EA/EI ratio in the range of 0.02 to 100, or a spring rate kt in the range of 500 to 0, as well as any combinations thereof. More preferably, the shear band has a GA/EI ratio of 0.01 to 5, or an EA/EI ratio of 1 to 50 and any subcombinations thereof. The tire tread is preferably wrapped about the shear band and is preferably integrally molded to the shear band.
A first embodiment of the non-pneumatic wheel 210 of the present invention is shown in
The non-pneumatic wheel is designed to support the weight of the vehicle for worry-free mobility on the road, while becoming vanes of a rotor for flight of the vehicle. The non-pneumatic tire is designed to be rotated 90 degrees for vertical takeoff and landing of the vehicle. As shown in
The nonpneumatic wheel also includes one or more cooling fins.
The tread structure of the nonpneumatic wheel is preferably porous, so that light from the light based sensor may also be used to sense the road or flight conditions.
Applicants understand that many other variations are apparent to one of ordinary skill in the art from a reading of the above specification. These variations and other variations are within the spirit and scope of the present invention as defined by the following appended claims.
| Number | Date | Country | |
|---|---|---|---|
| 62809075 | Feb 2019 | US |
