Abstract: A pneumatic tire, having a plurality of sipes formed in land portions of a tread thereof so as to each extend in the tire width direction, characterized in that: in a cross section of the land portion orthogonal to the sipe extending direction, provided that an imaginary sipe main line links two ends in the tire radial direction of each sipe, at least two of the sipes are “inclined sipes” each having the sipe main line inclined with respect to the tire radial direction; each inclined sipe has inner bent portions each protruding with respect to the sipe main line with peaks positioned deeper than 20% of the sipe depth; and the sipe main line(s) of at least one of the inclined sipes are inclined in a direction opposite, with respect to the tire radial direction, to the sipe main line of any of the other inclined sipes.

Abstract: A pneumatic tire (10), which has, in the surface of the tread (11), lug grooves (15) on one side extending from one axial edge towards the axial center of the tire in such a manner as to intersect with the circumferential direction of the tire and lug grooves (15) on the other side extending in a symmetrically opposite direction from the axial center towards the other axial edge of the tire, has at least one circumferential groove (12) extending circumferentially around the tire. Also, circumferential grooves (12, 13a, 13b) are so formed as to satisfy a relationship of “1?(S/L)?3” where L is the axial length of the central region, which is the region enclosed by two straight parallel lines each passing through the center between the contact width center (CL) and the contact edge with the shoulder regions being the regions axially outside of the parallel lines, and S is the total of the groove areas of the circumferential grooves (12, 13a, 13b) disposed in the central region.

Abstract: A pneumatic tire (10) has, in the surface of the tread (11), a central circumferential groove (12) located at the center of the contact patch width and extending circumferentially around the tire, a plurality of longitudinal grooves (13 (13a, 13b)) formed on the axially outside of the central circumferential groove (12), lug grooves (15), and blocks (16 (16a to 16c)) defined by the central circumferential groove (12), the longitudinal grooves (13), and the lug grooves (15). Each of the lug grooves (15) is formed such that its width in the shoulder region is greater than its width in the central region, and the sum of the groove area of the central circumferential groove (12) and the groove area of the longitudinal grooves (13) is smaller than the area of the lug grooves (15).

Abstract: A pneumatic tire, comprising: a tread surface; a plurality of grooves formed in the tread surface, including a plurality of widthwise grooves each extending from a corresponding tread end on the inner side in the tread width direction and a plurality of circumferential grooves each extending in the tread circumferential direction to intersect the widthwise grooves; blocks demarcated by the plurality of grooves; and a chamfered portion formed at a corner, on the trailing edge side and on the outer side in the tread width direction, of each block.

Abstract: Disclosed is a method for predicting tire performance in which a tire model, which comprises a tread pattern capable of imparting deformation by means of ground contact and/or transfer, and a snow model, in which a snow-covered road surface that comes into contact with the tire model is represented, are used to predict tire performance on the snow-covered road surface on the basis of physical quantities that occur in at least either of the tire model and the snow model. The snow model is modeled as an elasto-plastic body or an elastic body, the nonlinearity of the volume compression property of snow is represented by the relationship between the density or volume strain of the snow and the pressure of the snow, and the shear property of the snow is represented by the relationship between the yield stress of the snow and the pressure of the snow.

Abstract: A pneumatic tire (10) has, in the surface of the tread (11), a central circumferential groove (12) located at the center of the contact patch width and extending circumferentially around the tire, a plurality of longitudinal grooves (13 (13a, 13b)) formed on the axially outside of the central circumferential groove (12), lug grooves (15), and blocks (16 (16a to 16c)) defined by the central circumferential groove (12), the longitudinal grooves (13), and the lug grooves (15). Each of the lug grooves (15) is formed such that its width in the shoulder region is greater than its width in the central region, and the sum of the groove area of the central circumferential groove (12) and the groove area of the longitudinal grooves (13) is smaller than the area of the lug grooves (15).

Abstract: A pneumatic tire (10), which has, in the surface of the tread (11), lug grooves (15) on one side extending from one axial edge towards the axial center of the tire in such a manner as to intersect with the circumferential direction of the tire and lug grooves (15) on the other side extending in a symmetrically opposite direction from the axial center towards the other axial edge of the tire, has at least one circumferential groove (12) extending circumferentially around the tire. Also, circumferential grooves (12, 13a, 13b) are so formed as to satisfy a relationship of “1?(S/L)?3” where L is the axial length of the central region, which is the region enclosed by two straight parallel lines each passing through the center between the contact width center (CL) and the contact edge with the shoulder regions being the regions axially outside of the parallel lines, and S is the total of the groove areas of the circumferential grooves (12, 13a, 13b) disposed in the central region.

Abstract: A pneumatic tire, comprising: a tread surface; a plurality of grooves formed in the tread surface, including a plurality of widthwise grooves each extending from a corresponding tread end on the inner side in the tread width direction and a plurality of circumferential grooves each extending in the tread circumferential direction to intersect the widthwise grooves; blocks demarcated by the plurality of grooves; and a chamfered portion formed at a corner, on the trailing edge side and on the outer side in the tread width direction, of each block.

Abstract: A pneumatic tire, having a plurality of sipes formed in land portions of a tread thereof so as to each extend in the tire width direction, characterized in that: in a cross section of the land portion orthogonal to the sipe extending direction, provided that an imaginary sipe main line links two ends in the tire radial direction of each sipe, at least two of the sipes are “inclined sipes” each having the sipe main line inclined with respect to the tire radial direction; each inclined sipe has inner bent portions each protruding with respect to the sipe main line with peaks positioned deeper than 20% of the sipe depth; and the sipe main line(s) of at least one of the inclined sipes are inclined in a direction opposite, with respect to the tire radial direction, to the sipe main line of any of the other inclined sipes.

Abstract: Disclosed is a method for predicting tire performance in which a tire model, which comprises a tread pattern capable of imparting deformation by means of ground contact and/or transfer, and a snow model, in which a snow-covered road surface that comes into contact with the tire model is represented, are used to predict tire performance on the snow-covered road surface on the basis of physical quantities that occur in at least either of the tire model and the snow model. The snow model is modeled as an elasto-plastic body or an elastic body, the nonlinearity of the volume compression property of snow is represented by the relationship between the density or volume strain of the snow and the pressure of the snow, and the shear property of the snow is represented by the relationship between the yield stress of the snow and the pressure of the snow.

Abstract: The estimation of the performance of an actually used tire in the presence of a fluid, such as drainage performance, in-snow performance, and noise performance. A tire model and a fluid model based on a finite element method are constructed from a draft design of a tire including the shape, structure, and the like, and a road surface condition is inputted by selecting a coefficient of friction &mgr; in conjunction with the construction of a road surface model (Steps 100 to 106). Boundary conditions during tire rolling or tire nonrolling are set (Step 108); deformation calculation and fluid calculation of the tire model are performed (Steps 110 to 114); and a boundary surface between the tire model and the fluid model is recognized to update the boundary conditions (Steps 118 and 120). The result of calculation is outputted as a result of estimation, the result of estimation is evaluated (Step 122), and the draft design with satisfactory performance is adopted (Step 124 to 132).