| 摘要 |
Pural non-pneumatic (NPTs) are unitarily fitted, side-by-side, on a wheel rim, forming a multiple NPT (MNPT) to carry a load by sharing the load between the side-by-side NPTs. By "unitarily" is meant that the NPTs are fitted to the rim as a whole, without cutting or sectioning. With this construction, a MNPT is provided with characteristics which are surprisingly better than those attributable to a single NPT having the same or a different outer hoop diameter but the same mass of resin as the plural NPTs. The NPTs may be formed as rings, then by heat-distending them, unitarily post-fitted to the surface of an adhesively prepped wheel rim, for operation at relatively low torque; alternatively, and more preferably the NPTs are cast or otherwise thermoformed, as for example by injection molding, onto the wheel rim and self-adhesively autogenously secured, so as to provide the plural NPTs integrally bonded to the wheel rim. Dual spaced-apart NPTs on a wheel rim are unexpectedly advantageous in comparison to a single NPT, designed to carry the same load, irrespective of which of several constructions is used for the NPTs. First, the twin NPTs provide greater stability because the spaced apart twin webs lend far more stability than the single web. Second, the spring rate for a larger NPT having a higher web is lower than the spring rate for either of the dual NPTs. For the dual NPTs, this results in less road noise, a better 'ride' and greater comfort, each of which considerations assume greater significance as speed of the vehicle increases. Third, each of the dual NPTs generates substantially less heat, the difference getting progressively exaggerated as the speed of travel increases. It is easier to dissipate the heat generated by the dual smaller NPTs than it is to dissipate that generated by a single larger NPT of equivalent duty due mainly to the larger surface area presented by the twin NPTs. |
