GB1588922A - Wheel assembly comprising a wheel with a tyre thread mounted thereon - Google Patents

Description

(54) WHEEL ASSEMBLY COMPRISING A WHEEL WITH A TIRE TREAD MOUNTED THEREON (71) We, THE GOODYEAR TIRE & RUBBER COMPANY, a corporation organised under the laws of the state of Ohio, United States of America, of 1144 East Market Street, Akron, Ohio, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be perforrr.ed, to be particularly described in and by the following statement:- For many years, there has been a need for a non-pneumatic tire and wheel assembly for use as a spare tire in passenger cars and in low velocity off-the-road vehicles, e.g. farm and military equipment, as well as in certain commercial vehicles. Prior efforts over the last several decades have generally resulted in substantially rigid structures that did not provide the desired riding characteristics.

An example of one prior effort is United States Patent 2,016,095 issued October 1, 1935, in which a solid tire tread is cured to stiffening hoops made of tough spring steel tubes which is then affixed to a disc wheel formed of sheet metal.

United States Patent 3,807,474 discloses a high density, linear polyethylene hub structure carrying a locking rim on to which is moulded a tire which may be solid or hollow with a cord insert of resilient material. The hub structure disclosed is of substantially rigid material with the concept that the tires provide resilience.

British Patent 1,013,214 discloses a vehicle wheel including a non-pneumatic tire having a bead clamped between substantially radially extending flanges provided on the rim presumably of rigid metal, the resilience of the structure being provided in the means affixing the tread to the rim as well as the tread material itself.

All of the above prior attempts to provide a non-pneumatic tire and wheel assembly have failed to provide such a device having sufficient utility to make it commercially feasible. None of the prior art devices have achieved the mechanical functions and riding performance characteristics of a conventional pneumatic tire and wheel assembly.

The present invention provides a wheel assembly comprising (A) a wheel having a hub portion, a rim portion, and an interconnection portion meeting the hub and rim portions; wherein the hub portion is adapted for mounting on a vehicle axle, the rim portion slopes radially inwards from first edge to second edge where it meets the interconnection portion, and the said interconnection portion is sinuous in radial crosssection between its meeting points with the hub and rim portions by virtue of possessing a region of positive curvature and a region of negative curvature joined by a single point of inflection, and (B) a circumferential tire tread fixed at least around the outer face of the rim portion.

The invention will be further described with reference to the accompanying drawings, in which: Figure 1 is a front isometric view of an assembly of a wheel and tire tread embodying the present invention; Figure 2 is a rear isometric view of the assembly of Figure 1; Figure 3 is a diametric section of the wheel; Figure 4 is a partial diametric section of one embodiment of the present invention; Figure 5 is an enlarged partial section of the embodiment of Figure 4 shown in the mould; Figure 6 is a partial diametric section of another embodiment of the invention; and Figure 7 is an enlarged schematic diagram showing the general construction of the wheel of the embodiment of Figure 3.

Referring to Figures 1 and 2 the general concept of the present invention is shown. The wheel and tire tread assembly, designated generally by reference numeral 10, is comprised of a wheel having a moulded reinforced plastic hub portion 11 and rim portion, integrally interconnected by a portion of sinuous radial cross-section, as explained in more detail below, and carrying ground-engaging tread 13.

Tread 13 is moulded in situ from natural or synthetic rubber or other elastomeric material such as liquid injection microcellular urethane material. When rubber is used for the tread an adhesive must be used to join it to the rim whereas when the aforementioned urethane material is used for the tread it has natural adhesion to the rim and no additional adhesive is necessary.

The assembly according to one embodiment is shown in Figures 1 and 5 inclusive. Hub portion 11 is of conventional shape for mounting on a conventional vehicular wheel mount with a plurality of holes 14 through which extend the threaded members on the vehicular mount (not shown). The assembly is secured thereto by threaded members or nuts 14a (See Figure 1).

The rim portion as shown in Figure 3 has the shape of the frustum of a right circular cone 15. At the smaller diameter edge it merges integrally at 16 into an interconnection portion possessing, in radial cross-section, first a region 12 of positive curvature and then a region 20 of negative curvature joined by a single point of inflexion 17, thus being "sinuous" in cross-section as indicated above.

The cross-sectional region of positive curvature thus relates to a shape which can be considered as part of a radial cross-section of a torus. This interconnection portion in turn merges integrally at 21 into the hub portion 11.

The tip 23 of the rim portion is tapered as shown in Figures 3-5 to aid in controlling the shape of the tread foot print described below and in attaching tread 13 thereto as will be explained hereinafter. In addition, the wheel cross-section is tapered at points A and B (see also Figure 7) to provide a relatively constant working stress of low order of magnitude throughout the structure and minimize stress concentrations under high deflection loads or impacts.

The wheel is fabricated, for example, of fibreglass reinforced epoxide plastic having excellent long-term fatigue properties together with shock absorbing and damping characteristics associated with relatively slow de deflection recovery rates. One type of fibre reinforced plastic suitable for use with the present invention is described in my U.S.

Patents 3,988,089 and 4,130,154.

One method of moulding tread 13 to the rim portion is shown in Figure 5. The metallic mould is comprised of a top member 24 side member 25 and bottom member 26. The rim member itself constitutes part of the mould bottom together with seal pocket 27 and 0ring 28. The mould cavity 29 defined by the just mentioned parts is filled by injection of the elastomeric material through injection portion 30 to which is connected liquid supply tube 30. As can be seen, the tread 13 is provided with a rib configuration simulating a standard tire tread and is crowned on the outside half similar to that of a standard tire tread and is tapered on the inside half to allow for structural deflection curvature to balance the primary contact area in the centre rib 32 of the tread. This is done to achieve low rolling resistance as well as to control the load distribution into the structure while at the same time offering an increased lateral skid resisting area under cornering moments from either direction. The wider centre rib 32 is employed to aid in uniform tread-wear.

The shoulder 33 (see Figure 5) provides increased section modulus and protects the tread from curb abrasion and impacts. It also gives a more conventional appearance to the unit. The increased section modulus of this configuration increases the structural stiffness thereby reducing static deflection by about half that of the reinforced plastic structure alone.

The embodiment shown in Figure 6 shows a rim portion 34 integrally merging at 35 to a region 36 of positive curvature in radial cross-section, with a single point of inflexion 37 where it merges integrally with a region 38, 39, 40 of negative curvature in radial cross-section which further integrally merges at 41 to the edge 42 of a hub portion in the form of a central mounting disc 43. The structural thickness of all the aforesaid elements is adjusted to provide a relatively constant working stress of low order of magnitude throughout the structure and to minimize stress concentrations under high deflection loads or impacts.

The assembly shown in the examples func tions to provide a composite flexible structure having uniform cushioned load distribution and preventing curb abrasions. It provides traction and cornering deflection forces approaching those of a wheel with a pneumatic tire. Obvious advantages include: having the performance of such a wheel without the disadvantages associated with it going flat; eliminating the need for a spare tire on the vehicle; reducing the unsprung weight of the vehicle and its overall weight; increasing possible brake diameter and area; and providing increased clearance space for the suspension mechanism of the vehicle.

The assembly as shown is suitable for a wide range of vehicles, off-the-road, military, aircraft and commercial as well as passenger cars.

While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention.

WHAT WE CLAIM IS: 1. A wheel assembliy comprising (A) a wheel having a hub portion, a rim portion, and an interconnection portion meeting the hub and rim portions; wherein the hub

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   such as liquid injection microcellular urethane material. When rubber is used for the tread an adhesive must be used to join it to the rim whereas when the aforementioned urethane material is used for the tread it has natural adhesion to the rim and no additional adhesive is necessary.

   The assembly according to one embodiment is shown in Figures 1 and 5 inclusive. Hub portion 11 is of conventional shape for mounting on a conventional vehicular wheel mount with a plurality of holes 14 through which extend the threaded members on the vehicular mount (not shown). The assembly is secured thereto by threaded members or nuts 14a (See Figure 1).

   The rim portion as shown in Figure 3 has the shape of the frustum of a right circular cone 15. At the smaller diameter edge it merges integrally at 16 into an interconnection portion possessing, in radial cross-section, first a region 12 of positive curvature and then a region 20 of negative curvature joined by a single point of inflexion 17, thus being "sinuous" in cross-section as indicated above.

   The cross-sectional region of positive curvature thus relates to a shape which can be considered as part of a radial cross-section of a torus. This interconnection portion in turn merges integrally at 21 into the hub portion 11.

   The tip 23 of the rim portion is tapered as shown in Figures 3-5 to aid in controlling the shape of the tread foot print described below and in attaching tread 13 thereto as will be explained hereinafter. In addition, the wheel cross-section is tapered at points A and B (see also Figure 7) to provide a relatively constant working stress of low order of magnitude throughout the structure and minimize stress concentrations under high deflection loads or impacts.

   The wheel is fabricated, for example, of fibreglass reinforced epoxide plastic having excellent long-term fatigue properties together with shock absorbing and damping characteristics associated with relatively slow de deflection recovery rates. One type of fibre reinforced plastic suitable for use with the present invention is described in my U.S.

   Patents 3,988,089 and 4,130,154.

   One method of moulding tread 13 to the rim portion is shown in Figure 5. The metallic mould is comprised of a top member 24 side member 25 and bottom member 26. The rim member itself constitutes part of the mould bottom together with seal pocket 27 and 0ring 28. The mould cavity 29 defined by the just mentioned parts is filled by injection of the elastomeric material through injection portion 30 to which is connected liquid supply tube 30. As can be seen, the tread 13 is provided with a rib configuration simulating a standard tire tread and is crowned on the outside half similar to that of a standard tire tread and is tapered on the inside half to allow for structural deflection curvature to balance the primary contact area in the centre rib 32 of the tread. This is done to achieve low rolling resistance as well as to control the load distribution into the structure while at the same time offering an increased lateral skid resisting area under cornering moments from either direction. The wider centre rib 32 is employed to aid in uniform tread-wear.

   The shoulder 33 (see Figure 5) provides increased section modulus and protects the tread from curb abrasion and impacts. It also gives a more conventional appearance to the unit. The increased section modulus of this configuration increases the structural stiffness thereby reducing static deflection by about half that of the reinforced plastic structure alone.

   The embodiment shown in Figure 6 shows a rim portion 34 integrally merging at 35 to a region 36 of positive curvature in radial cross-section, with a single point of inflexion

   37 where it merges integrally with a region 38, 39, 40 of negative curvature in radial cross-section which further integrally merges at 41 to the edge 42 of a hub portion in the form of a central mounting disc 43. The structural thickness of all the aforesaid elements is adjusted to provide a relatively constant working stress of low order of magnitude throughout the structure and to minimize stress concentrations under high deflection loads or impacts.

   The assembly shown in the examples func tions to provide a composite flexible structure having uniform cushioned load distribution and preventing curb abrasions. It provides traction and cornering deflection forces approaching those of a wheel with a pneumatic tire. Obvious advantages include: having the performance of such a wheel without the disadvantages associated with it going flat; eliminating the need for a spare tire on the vehicle; reducing the unsprung weight of the vehicle and its overall weight; increasing possible brake diameter and area; and providing increased clearance space for the suspension mechanism of the vehicle.

   The assembly as shown is suitable for a wide range of vehicles, off-the-road, military, aircraft and commercial as well as passenger cars.

   While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention.

   WHAT WE CLAIM IS: 1. A wheel assembliy comprising (A) a wheel having a hub portion, a rim portion, and an interconnection portion meeting the hub and rim portions; wherein the hub

   portion is adapted for mounting on a vehicle axle, the rim portion slopes radially inwards from first edge to a second edge where it meets the interconnection portion, and the said interconnection portion is sinuous in radial cross-section between its meeting points with the hub and rim portions by virtue of possessing a region of positive curvature and a region of negative curvature joined by a single point of inflection, and (B) a circumferential tire tread fixed at least around the outer face of the rim portion.
2. 2. A wheel assembly as claimed in Claim 1, in which the said rim portion is shaped as the frustum of a right circular cone.
3. 3. A wheel assembly as claimed in Claim 1 or 2, in which the region of positive curvature is shaped as part of a radial cross-section of a torus.
4. 4. A wheel assembly as claimed in any one preceding Claim, in which said first edge of the rim is tapered in axial cross-section and in which the tire tread embeds at least said tapered edge.
5. 5. A wheel assembly as claimed in any one of the preceding Claims 1 to 4, in which the tire tread is moulded in situ and is of natural rubber, synthetic rubber or polyurethane.
6. 6. A wheel assembly as claimed in any one of the preceding Claims 1 to 5, in which the rim and interconnection portions are made of an epoxide polymer reinforced with glass fibre, and in which, where the interconnection portion meets the rim portion and/or where it meets the hub portion, the polymer is of a reduced thickness to increase overall resilience.
7. 7. A wheel assembly as claimed in any one preceding Claim, in which the mounting adaptation on the hub is such that said first edge of the rim portion faces away from the vehicle to give a curb-side-open structure.
8. 8. A wheel assembly as claimed in Claim 1, and substantially as herein described with reference to and as illustrated in any Figure of the accompanying drawings.