The Yokohama Rubber Co., Ltd.

Kazuyuki Kabe

Tuneo Morikawa

Ken Takahashi

Nobuo Suzuki

Shuji Takahashi

Tsuneo Morikawa

Naoshi Miyashita

Ryoji Hanada

Tatsuo Suzuki

Shuichi Tsukada

Seiichi Nomura

Tomohiko Kogure

Daisuke Irii

Michihiko Sugiura

Yoshihiro Inomata

Izumi Kuramochi

Kohtaroh Iwabuchi

Masataka Koishi

Hideki Seto

Satoru Isobe

Masashi Kida

Masahiko Kanamaru

Hitoshi Horie

Nobuhiro Yamashita

Atao Kishi

Yukio Kaga

Hajime Tomoda

Kenichiro Nishida

Masahiko Mizuno

Keita Rachi

Masaki Kato

Saichi Harada

The overall material constant of a composite material is computed where the composite material includes multiple kinds of material components in a matrix phase, each of the material constants of the material components and the matrix phase being known. First, for the composite material, an equation, having the material constant of a virtual composite material as an unknown, is prepared by defining the virtual composite material in which each of the material components is dispersed in a form of spherical particles in the matrix phase at a known volume fractions. Next, the overall material constant of the virtual composite material is found as the overall material constant of the composite material by solving the equation. In this case, the equation is a recursive equation which is obtained using the self-consistent method. The volume fraction of a material component in the composite material is computed using the equation.

Computational method of material constant of composite material and volume fraction of material component in composite material, and recording medium

In a method of computing the overall material constant of a composite material, a virtual composite material is defined as the one that a first material component is dispersed in a form of inner spherical particles in a matrix phase and each of the inner spherical particles is enveloped by the second material component, in a form of outer shell layers, as a coating layer. Based on this, a nonlinear equation is prepared, which has the material constant of the virtual composite material as an unknown. Next, the material constant of the virtual composite material is computed by solving the equation. In the equation, the material constant in each of the surrounding areas of the outer shell layers coating the inner spherical particles is defined as the overall material constant of the virtual composite material to be computed. The volume fractions of the material components in the composite material are computed using the equation.

Computation method of mechanical material constant of composite material and volume fraction of material component in composite material, and recording medium

The present invention provides a pneumatic tire that inhibits any fatigue rupture at an edge portion of a circumferential-direction reinforcing belt layer and also inhibits any separation at an edge portion of crossed belt layers. In the pneumatic tire, at least two crossed belt layers are disposed on the outer circumferential side of a carcass layer in a tread portion. At least one circumferential-direction reinforcing belt layer with a width smaller than those of the crossed belt layers is disposed between the crossed belt layers. Moreover, a stress relaxation layer of a rubber composition having a fixed thickness is disposed between the crossed belt layers while lying adjacent to an edge portion of and outside, in the width directions of, the circumferential-direction reinforcing belt layer.

Pneumatic tire

In computing the overall material constant of a composite material, a virtual composite material is defined as the one that predetermined material components are dispersed in a form of spherical particles in a matrix phase at known volume fractions, and a nonlinear equation having the overall material constant of the virtual composite material as an unknown is prepared. Next, the overall material constant of the composite material is computed by solving the nonlinear equation. The nonlinear equation is a recursive nonlinear equation which is obtained by defining the material constant in the surrounding areas of the spherical particles as the overall material constant of the composite material to be computed. The volume fraction of a material component dispersed in the composite material is computed using the recursive nonlinear equation.

A transient response of a tire is simulated by using a effective data of a physical amount. The physical amount is set as a rolling condition of the tire and varies in time. The effective data of the physical amount is calculated by a convolution integral of a response function of an introduced first-order lag response and a time gradient of time-series data of the physical amount. In a tire model determining method, a time constant of a response function of the first-order lag response is determined from measured transient response data. In a tire transient response data calculating method, a transient response data is calculated by using the effective data of the physical amount which is calculated by using a desired physical amount and the first-order lag response.

Tire model determining method, tire transient response data calculating method, tire evaluating method, and tire designing method

The tire transient response data obtained while cornering with a slip angle is calculated based on a tire dynamic model. The deformation response of a tread part in the tire dynamic is set as a first-order-lag response. The value of the transient response parameter is initialized in order to define the first-order-lag response. The time-series data of the transient response of the slip angle between the tread part and the road surface in the tire dynamic model is obtained by computing the convolution integral of the defined response function of the first-order-lag response with a time gradient of the time-series data of the slip angle. The value of a lateral force is calculated by using the tire dynamic model based on the time-series data of the transient response of the slip angle thus obtained. Accordingly, the transient response data is calculated and the value of the transient response parameter is obtained.

Tire transient response data calculating method, data processing method, tire designing method, vehicle motion predicting method, and tire cornering characteristic evaluation method and evaluation device therefor

A pneumatic tire has two belt layers, each having a plurality of strip pieces formed by pulling together and rubberizing a plurality of steel cords. Strip piece width, strip piece thickness, belt layer cord angle with respect to a tire circumferential direction, numbers of the strip pieces of inner and outer belt layers, and circumferential lengths of the inner and outer belt layers are respectively denoted by A, G, &#x3b8;, N, N, Land L. Nis equal to N, and Nis an integer satisfying L=N&#xd7;A/sin &#x3b8;. The inner belt layer is formed by joining the Nstrip pieces so each side of each strip piece is butted with one side of another strip piece. The outer belt layer is formed by aligning the Nstrip pieces on the inner belt layer in the tire circumferential direction with spaces of width 2&#x3c0;G/Ndisposed between adjacent strip pieces.

Pneumatic tire with belt layer including a plurality of strip pieces and method of manufacturing the same

Values of multiple tire dynamic element parameters are set for a tire dynamic model constructed using the tire dynamic element parameters for calculating a tire axial force and a self-aligning torque under a given slip ratio. Next, the values of the tire axial force and the self-aligning torque are calculated using the tire dynamic model and output. The tire dynamic model allows a center position of a contact patch thereof against a road surface to move in accordance with a longitudinal force that occurs as the tire axial force when a slip ratio in a braking/driving direction is given so that a position of the contact patch moves in a longitudinal direction due to the longitudinal force. When designing a vehicle or when designing a tire, the tire dynamic model is used.

Tire characteristic calculation method, tire dynamic element parameter value derivation method, vehicle traveling simulation method, and tire designing method and vehicle designing method in which consideration is given to tire friction ellipse

In a prediction of abrasion characteristic of a tire, a characteristic curve of a tire axis force generated on a tire rotation axis at the slip ratio applied to the tire and changed depending upon the slip ratio is acquired. From the characteristic curve, values of tire dynamic element parameters determining the characteristic curve are derived based on a tire dynamic model constituted by the tire dynamic element parameters. Furthermore, a tire sliding amount based on a sliding region, the sliding region and an adhesive region formed on the contact patch of the tire at the applied slip ratio are calculated by applying the values of the tire dynamic element parameters to the model. Lastly, an abrasion characteristic of a tread part of the tire at the applied slip ratio is predicted by using the tire sliding amount with abrasion characteristic data of a tread rubber of the tread part. According to the prediction results, a tire is designed and produced.

Tire abrasion predicting method, tire designing method, tire manufacturing method, tire abrasion predicting system, and program

A method for tire parameter derivation, tire cornering characteristic calculation and tire design is used with a tire dynamic model constituted by using a plurality of tire dynamic element parameters including stiffness and friction coefficient and parameter defining a distribution of contact pressure of the tire. The parameters and tire cornering characteristic are derived by using the combined sum of squared residuals being obtained by weighted addition of a first sum of squared residuals of lateral force and a second sum of squared residuals of self-aligning torque. The tire dynamic model is a model for calculating a lateral force and for calculating a self-aligning torque separately as a lateral force-based torque component generated by the lateral force applied on a contact patch of the tire and a longitudinal force-based torque component generated by a longitudinal force applied on the contact patch of the tire.

Tire parameter deriving method, tire cornering characteristic calculating method, tire designing method, vehicle dynamics analyzing method, and program

In a tire designing method, at least one of a tire profile shape, a shape of a tire component member and physical property data of the tire component member is tentatively selected as a parameter to prepare an initial tire model () representing the pneumatic tire by using a finite number of elements, and at least one of a stress acting on the initial tire model by the inner pressure filling processing and the physical property data used for the initial tire model is modified corresponding to a predetermined measure of elapsed time, to thereby deform the initial tire model and a tire profile shape after a change with time is predicted by using the deformed initial tire model. By preparing the tire model () with the predicted tire profile shape and applying the inner pressure filling processing and road contact processing thereto, the maximum principal strains in the elements of the tire model () are calculated, and the margins of safety of the tire component members are calculated by using the maximum principal strains. The tentatively selection is repeated until the calculated margins are equal to or larger than a pre-set reference margin of safety so that a tire with excellent durability can be designed.

Tire designing method and program

Disclosed is a method of designing rubber composite executed as follows. A shape of the rubber composite, a shape of the each part (i) constituting the rubber composite and physical properties of a rubber material used for each part (i) are tentatively selected respectively. Thereafter, the rubber composite is divided into many finite elements, and strain in each element is calculated by the finite element method to obtain maximum principal strain (&#x3b5;)of the elements in each part (i). Then, the tentative selections of the shape of the rubber composite, the shape of each part (i) and the physical properties of the rubber material, and the calculations by the finite element method are repeated until an allowance ratio Scalculated as a ratio of strain (&#x3b5;)at break to the maximum strain (&#x3b5;)becomes equal to a specified reference allowance ratio Sor higher in all of the parts (i). The shape of the rubber composite, the shape of each part (i) and the physical properties of the rubber material are thus determined.

Method of designing rubber composite

A golf ball whose core is covered with a cover, wherein the core is constituted of a rubber composition containing polybutadiene rubber and the cover is constituted of a resin composition composed of ionomer resin and diene rubber. A golf ball cover material composition composed of ionomer resin, diene rubber and non-staining antioxidant. A method of manufacturing a golf ball cover material composition constituted by mixing/kneading ionomer resin and diene rubber.

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Kanagawa, Japan

Kazuyuki Kabe