摘要:
A pneumatic radial tire for heavy loads, having steel belt layers provided on the inner side of a tread, and a tread pattern having a plurality of divisional ribs separated by a plurality of main grooves extending in the circumferential direction of the tire, characterized in that at least the inner vertical surfaces of left and right outermost main grooves out of the main grooves are formed so as to extend zigzag in the circumferential direction of the tire, narrow grooves which extend continuously in the circumferential direction of the tire being provided at the shoulder side edge portions of ribs internally adjacent to the outermost main grooves, the width W.sub.4 of the narrow grooves being set to a level in the range of 0.5-1 mm, the axes of the narrow grooves which extend in the direction of the depth thereof being inclined in the downwardly inward direction with respect to a normal of the tread surface, the narrow grooves forming laterally separated rib bodies and narrow ribs the height of which is smaller than that of the rib bodies, a ratio of a maximum width W.sub.2 of the narrow ribs to a total width W.sub.1 of the ribs on the inner side of the outermost main grooves being set to a level satisfying the relation W.sub.2 /W.sub.1 .ltoreq.0.3, an angle .alpha..sub.1 between the side surface which faces the relative outermost main groove of a maximum width portion of each narrow rib and a normal of the tread surface being set smaller than an angle .alpha..sub.2 between the side surface which faces the relative outermost main groove of a minimum width portion of each narrow rib and the same normal.
摘要:
A flat heavy-duty pneumatic radial tire having a 0-degree belt layer formed of steel cords and increased in durability, wherein multiple plies of steel cord belt layers (6) are disposed on the outer periphery of a carcass layer (4). The steel cord belt layers (6) includes at least one ply of the 0-degree belt layer with a cord angle of substantially 0° relative to the circumferential direction of the tire and at least two plies of bias belt layers (8) with a cord angle substantially equal to an equilibrium angle of within a range of 45° to 65° relative to the circumferential direction of the tire. The tire is manufactured as follows. The tire cured and molded in a mold is released from the mold, assembled with a rim to be inflated while the tire is hot, and then cooled to normal temperature under the inflated condition.
摘要:
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 (εi)max 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 Sia calculated as a ratio of strain (εi)b at break to the maximum strain (εi)max becomes equal to a specified reference allowance ratio S0 or 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.
摘要:
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.
摘要:
A pneumatic radial tire has at least two belt layers disposed at a tread portion thereof, wherein the two belt layers are constituted by inclining a strip formed by aligning a plurality of reinforcing cords to a tire circumferential direction and extending it zigzag in the tire circumferential direction so that the strip is turned back from the lower belt layer to the upper belt layer at both end portions of the two belt layers, and zone portions in which the reinforcing cords incline to the right in the tire circumferential direction and the zone portions in which the reinforcing cords incline to the left in the tire circumferential direction are alternately arranged.
摘要:
A heavy duty and medium pneumatic radial tire having a belt layer composed of at least three layers between a carcass layer and a tread, wherein the first belt layer as numbered from the carcass layer towards the tread is separated into two parts at the central region of a crown and at least one organic fiber cord layer is disposed in a space formed by the separation of the first belt layer.
摘要:
A radial tire with a split structure in the first belt layer provided with an organic fiber cord layer in the split structure and having a narrow groove extending in the circumferential direction of the tire and provided in each of both shoulder portions of the surface of a tread, wherein the narrow groove has a depth h determined in the radial direction of the tire, and a distance d.sub.1 measured between the internal edge on the shoulder side of an opening portion of the narrow groove and the radially outermost surface of the shoulder portion as determined along a parallel line to the surface of the tread, and a distance d.sub.2 measured between the internal wall surface on the shoulder side of the bottom of the narrow groove and the radially outermost surface of the shoulder portion as determined along a parallel line to the surface of the tread, wherein d.sub.1 is less than 15 mm and is smaller than d.sub.2, and a shape factor m defined by the following equation is 0.8 to 1.2: ##EQU1##
摘要:
An improvement in the structure of the belt portion of a heavy duty radial tire for use in trucks, large-size buses, small-sized trucks, etc., and more particularly, a heavy duty pneumatic radial tire improved with respect to the driving stability under heavy duty conditions while ensuring the durability of the tire (belt portion) during high speed running through the provision of at least three belt layers between the tread surface and the carcass layer of the tire and the specification of the relationships between the angles of the cords constituting these plurality of belt layers.
摘要:
A pneumatic tire having a tread reinforcement layer constituted by a steel cord strip layer adjacent the carcass and an aromatic polyamide cord strip layer superposed to the steel cord strip layer in a parallel side-by-side relationship. The aromatic polyamide cord strip layer is folded at its both edges toward the center, in such a manner that the folded portions contact the main portion in a parallel side-by-side relationship. The main portion has a width ranging between 100 and 110% of the width of the tread surface, while the width of each folded portion ranges between 27.5 and 35% of the width of main portion. Furthermore, the free edge of each folded portion is located at a distance from the center of the outermost circumferential groove in the tread surface, which distance being between 25 and 75% of the distance between the outermost groove and the adjacent groove.
摘要:
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.