Measuring and testing – Tire – tread or roadway
Reexamination Certificate
2000-05-05
2002-08-13
Oen, William (Department: 2855)
Measuring and testing
Tire, tread or roadway
Reexamination Certificate
active
06430993
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of estimating tire performance, a method of fluid simulation, a method of designing a pneumatic tire, a method of designing a vulcanizing mold for a tire, a method of make a vulcanizing mold for a tire, a method of manufacturing a pneumatic tire, an optimization analyzer, a recording medium with a tire-performance estimation program recorded thereon, and a recording medium with a tire optimization analysis program recorded thereon. Specifically, the present invention relates to a tire-performance estimating method for estimating the performance of a pneumatic tire used in an automobile or the like, particularly the tire performance in the presence of a fluid such as the drainage performance, in-snow performance, and noise performance, a fluid simulation method for simulating the flow of a fluid around a tire, a method of designing a pneumatic tire, a method of designing a vulcanizing mold for a tire for designing a vulcanizing mold for manufacturing a tire, a method of manufacturing a pneumatic tire, and a recording medium with a tire-performance estimation program recorded thereon, or a method of designing a pneumatic tire which makes it possible to efficiently and easily design and develop the structure, shape and the like of a tire for attaining the single-purpose performance, mutually incompatible performances and the like of the tire, and which makes it possible to determine an optimal structure and shape of the tire and design a tire exhibiting high cost performance, as well as an optimization analyzer and a recording medium with a tire optimization analysis program recorded thereon.
BACKGROUND ART
Conventionally, in the development of a pneumatic tire, tire performance is obtained by conducting performance tests by actually designing and fabricating a tire and mounting it on an automobile, and a procedure has been adopted in which the development is redone starting from the design and fabrication unless the results of the performance tests are satisfactory. In recent years, owing to the development of numerical analysis techniques such as the finite element method and the computer environment, it has become possible to estimate by computers such as the state of inflation of the tire with internal pressure and the state of load at the time the tire is not rolling, and it has become possible to estimate a number of performances from this estimation. However, it has hitherto been impossible to compute those tire performances that are determined by the behavior of a fluid, such as the drainage performance, in-snow performance, and noise performance. For this reason, the present situation is such that it is impossible to conduct the estimation of tire performance and efficiently perform tire development.
A technical document is known in which an attempt was made to analyze the drainage performance, particularly hydroplaning, of a tire with respect to a smooth tire (grooveless tire) and a tire provided with only circumferential grooves (“Tire Science and Technology, TSTCA, Vol. 25, No. 4, October-December, 1997, pp. 265-287”).
However, in this conventional technical document, analysis is attempted with respect to only the smooth (i.e., grooveless) tire and the tire provided with only circumferential grooves, and no reference is given to tires with patterns having inclined grooves intersecting the circumferential direction of the tire, which largely contribute to the drainage performance in actual tires, nor to how the fluid during the ground contacting and rolling of the tire can be brought close to a flowing state and how transient analysis can be made possible. Namely, no consideration is given to the analysis in which an actual environment is assumed with respect to an actual tire.
In view of the above-described facts, an object of the invention is to obtain a method of estimating tire performance which is capable of facilitating the estimation of the performance of an actually used tire in the presence of a fluid, such as the drainage performance, in-snow performance, and noise performance, a method of fluid simulation, a method of designing a pneumatic tire which renders tire development efficient and is capable of obtaining a tire exhibiting excellent performance, a method of designing a vulcanizing mold for a tire, a method of making a vulcanizing mold for a tire, a method of manufacturing a pneumatic tire, and a recording medium with a tire-performance estimation program recorded thereon.
The design of tires has been based on experiential rules obtained through repeated numerical experiments using experiments and computers. For this reason, the number of trial manufactures and tests required for development has been enormously large, resulting in increased development cost and making it impossible to readily reduce a development period.
The design of a tire includes the design of the structure, shape, and pattern of the tire. To design the structure, shape, and pattern of the tire is to determine, for example, the structure, shape, pattern, and manufacturing conditions for obtaining the targeted tire performance. This tire performance is a result of evaluation of physical quantities determined by computations and experiments as well as actual-vehicle feeling. The conventional methods of designing a tire including, for example, the design of the structure, shape, and pattern of the tire have been based on experiential rules obtained on a trial-and-error basis through repeated numerical experiments using experiments and computers. For this reason, the number of trial manufactures and tests required for development has been enormously large, resulting in increased development cost and making it impossible to readily reduce the development period.
As means for overcoming these problems, techniques for obtaining optimal solutions have been proposed such as optimization methods using mathematical programming and genetic algorithms. As a technique relating to this mathematical programming, the present applicant already proposed a designing method disclosed in already-filed International Publication No. WO 94/16877.
Obtaining an optimal solution is likened to mountain-climbing. At this time, since the altitude of the mountain is related to the performance, the optimal solution corresponds to the peak of the mountain. In a case where the objective function is simple, its design space (i.e., the shape of the mountain) has the shape of a mountain with one peak, so that the optimal solution can be obtained by an optimization technique based on mathematical programming.
In the development of a pneumatic tire, the tire performance to be considered is obtained by conducting performance tests by actually designing and fabricating a tire and mounting it on an automobile, and a procedure has been adopted in which the development is redone starting from the design and fabrication unless the results of the performance tests are satisfactory. In recent years, due to the development of numerical analysis techniques such as the finite element method and the computer environment, it has become possible to estimate by the computer such as the state of inflation of the tire with internal pressure and the state of load when the tire is not rolling, and it has become possible to estimate a number of performances from this estimation. However, it has been impossible to compute those tire performances that are determined by the behavior of a fluid, such as the drainage performance, in-snow performance, and noise performance. For this reason, the present situation is such that it has been impossible to conduct the estimation of tire performance and efficiently perform tire development.
A technical document is known in which an attempt was made to analyze the drainage performance, particularly hydroplaning, of a tire with respect to a smooth tire (grooveless tire) and a tire provided with only circumferential grooves (“Tire Science and Technology, TSTCA, Vol. 25, No. 4, October-December, 1997, pp. 265-287”).
However, in such conventional con
Oen William
Sughrue & Mion, PLLC
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