Patent Application
20210154958
The present invention relates generally to vehicle tires and non-pneumatic tires, and more particularly, to a method of making a non-pneumatic tire.
The pneumatic tire has been the solution of choice for vehicular mobility for over a century. The pneumatic tire is a tensile structure. The pneumatic tire has at least four characteristics that make the pneumatic tire so dominate today. Pneumatic tires are efficient at carrying loads, because all of the tire structure is involved in carrying the load. Pneumatic tires are also desirable because they have low contact pressure, resulting in lower wear on roads due to the distribution of the load of the vehicle. Pneumatic tires also have low stiffness, which ensures a comfortable ride in a vehicle. The primary drawback to a pneumatic tire is that it requires compressed fluid. A conventional pneumatic tire is rendered useless after a complete loss of inflation pressure.
A tire designed to operate without inflation pressure may eliminate many of the problems and compromises associated with a pneumatic tire. Neither pressure maintenance nor pressure monitoring is required. Structurally supported tires such as solid tires or other elastomeric structures to date have not provided the levels of performance required from a conventional pneumatic tire. A structurally supported tire solution that delivers pneumatic tire-like performance would be a desirous improvement.
Non-pneumatic tires are typically defined by their load carrying efficiency. “Bottom loaders” are essentially rigid structures that carry a majority of the load in the portion of the structure below the hub. “Top loaders” are designed so that all of the structure is involved in carrying the load. Top loaders thus have a higher load carrying efficiency than bottom loaders, allowing a design that has less mass.
Thus, an improved non-pneumatic tire is desired that has all the features of the pneumatic tires without the drawback of the need for air inflation is desired.
The present invention will be better understood through reference to the following description and the appended drawings, in which:
The present invention is directed to a method of making a non-pneumatic tire, the non-pneumatic tire comprising a ground contacting annular tread portion comprising a tread rubber composition, a shear band comprising a cord reinforced rubber composition and disposed radially inward of the tread portion, and at least one spoke disk disposed radially inward of the shear band; wherein the spoke disk has an outer ring, and an inner ring, and a first and second spoke extending radially between the outer ring and the inner ring, wherein the first and second spokes are connected at a joint; the method comprising the steps of: applying a curable adhesive as an interface between a radially outermost surface of the spoke disk and a radially innermost surface of the shear band in its uncured state, assembling the tread portion in an uncured state, the shear band in an uncured state, and the at least one spoke disk to form a pre-assembly, and curing the pre-assembly.
A first embodiment of a non-pneumatic tire 100 of the present invention is shown in
The non-pneumatic tire may have different combination of spoke disks in order to tune the non-pneumatic tire with desired characteristics. For example, a first spoke disk 500 may be selected that carries both shear load and tensile load. A second spoke disk may be selected that carries a pure tensile load.
The tread portion 200 may have no grooves or may have 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 200 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 300 is preferably annular and is shown in
One embodiment of a non-pneumatic tire is shown in
The spoke disks are preferably formed of an elastic material, more preferably, a thermoplastic elastomer. The material of the spoke disks is selected based upon one or more of the following material properties. The tensile (Young's) modulus of the disk material is preferably in the range of 45 MPa to 650 MPa, and more preferably in the range of 85 MPa to 300 MPa, using the ISO 527-1/-2 standard test method. The glass transition temperature is less than −25 degree C., and more preferably less than —35 degree C. The yield strain at break is more than 30%, and more preferably more than 40%. The elongation at break is more than or equal to the yield strain, and more preferably, more than 200%. The heat deflection temperature is more than 40 degree C. under 0.45 MPa, and more preferably more than 50 degree C. under 0.45 MPa. No break result for the Izod and Charpy notched test at 23 degree C. using the ISO 179/ISO180 test method. Two suitable materials for the disk is commercially available by DSM Products and sold under the trade name ARNITEL PL 420H, PL461, PM 581, EM 630, and ID2060 HT.
The adhesive bond between the spoke disks 500 and the shear band 300, is accomplished using an appropriate adhesive as an interface between the outermost surface of the spoke disk 590 and the innermost surface of 350 of shear band 300 that bonds effectively between thermoplastic and elastomer. In one embodiment, the adhesive bond between the spoke disks 500 and the shear band 300 is formed by application of a two-part adhesive followed by co-curing of the adhesive with the shear band after assembly of the parts shown in
The adhesive may be applied in thin layers to radially innermost surface 350 of shear band 300, followed by assembly of the various components. The adhesive may be applied for example manually using a brush, sponge, trowel, spatula or the like.
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.
