The Yokohama Rubber Co., Ltd.

Hiroshi Furusawa

Yoshimasa Hashimoto

Kenichi Sato

Masaaki Nagayasu

Kenichiro Endo

Izumi Kuramochi

Takumi Morito

Hirohisa Hazama

Daisuke Watanabe

Kenichirou Endou

Makoto Ishii

Masaaki Miyoshi

Mitsuru Hirama

A pneumatic tire includes lug grooves in a tread surface of a shoulder land, the lug grooves crossing a circumferential direction and terminating at a first side within the shoulder land and passing through a contact edge at a second side; and a notch formed on an opening edge of the lug grooves, the notch being cutout from the tread surface cut radially inward. The lug grooves have a width decreasing from the first to the second side, an end position of the lug grooves is disposed from a main groove from 5% to 35% of a lateral dimension from the main groove to the ground contact edge, and a maximum groove width position is disposed from the main groove 40% or less of the lateral dimension from the main groove to the ground contact edge; and the notch has a width that increases from the first to the second side.

Pneumatic tire

A pneumatic tire includes lug grooves arranged in a circumferential direction in a tread surface of a land portion defined by two main grooves adjacent in a lateral direction, the lug grooves each crossing the circumferential direction and communicating at both ends with the main grooves, defining the land portion in the circumferential direction. A notch portion is formed on an opening edge of the lug grooves. The notch portion is cutout from the tread surface inward in a radial direction. The lug grooves have a maximum groove width at a position from 30% to 70% of a lateral direction dimension of the land portion from one of the main grooves and a groove width that decreases from the maximum groove width to the main grooves. The notch portion has a notch width that increases from a position of the maximum groove width of the lug grooves to the main grooves.

A pneumatic tire is provided with, in the tread surface, land portions that include a rib or a plurality of blocks. The land portions are provided with a plurality of narrow shallow grooves and a plurality of recessed portions in a contact patch. The opening area ratio Se of the recessed portions in the end portion regions in the tire lateral direction of one continuous contact patch and the opening area ratio Sc of the recessed portions in the central portion region in the tire lateral direction have the relationship Sc&#x3c;Se, where the central portion region is defined as the region in the central portion in the tire lateral direction occupying 50% of the continuous contact patch of the land portions, and the end portion regions are defined as the regions in the left and right end portions in the tire lateral direction occupying 25%.

There is provided a pneumatic tire, in which a first set of blocks that is partitioned and formed by two first circumferential grooves and a plurality of first lateral grooves is provided in the center region that includes the tire equatorial plane, a second set of blocks that is partitioned and formed by one second circumferential groove and a plurality of second lateral grooves is provided in the outermost portion in the tire width direction on each side in the tire width direction, a rib is provided between the first set of blocks and the second sets of blocks, the rib is divided by at least one third circumferential groove, and a plurality of sipes is formed in the first set of blocks, the second set of blocks, and the rib.

Automobile tire

The present technology relates to a pneumatic tire in which a plurality of small blocks is delineated and formed by a plurality of rectilinear circumferential narrow grooves and a plurality of widthwise narrow grooves that communicate with the circumferential narrow grooves, and small block rows with the small blocks aligned along a tire circumferential direction are formed between adjacent circumferential narrow grooves. Each of the small blocks has a surface area differing from that of at least one small block that belongs to an adjacent small block row on at least one side with respect to a tire width direction and has an overlapping tire circumferential directional region. The small blocks have surface areas of no less than 20 mmand no more than 400 mm.

In a pneumatic tire, a single block includes a first sipe and a second sipe each extending in a tire width direction and disposed at a predetermined pitch in a tire circumferential direction. The first sipe and the second sipe include a first sipe portion that has a linear form when the block is viewed planarly, and a second sipe portion that has a zigzag shape when the block is viewed planarly and that connects to the first sipe portion. The first sipe portion includes a pair of sipe wall faces that face each other and have a linear form when viewed as a cross-section from a direction perpendicular to a sipe length direction, and includes a protrusion disposed on a first face of the sipe wall faces and a recess disposed on a second face of the sipe wall faces so as to mate with the protrusion.

A pneumatic tire has a good balance between on-ice and on-snow performances. The tire includes a tread portion having longitudinal and lateral grooves defining block rows. Each block in the block rows includes sipes. A length of each block in the first and second block rows is not less than 1.5 times and not more than 2.5 times a length of each third block row block. A width of each second block row block is larger than a width of each first block row block. The lateral grooves defining the first and second block row blocks are offset in the tire circumferential direction by not less than 0.2 times and not more than 0.8 times the length of each first block row block. The lateral grooves defining the second and third block row blocks communicate with each other while inclining in the same direction.

A pneumatic tire including rib-like land portions partitioned by a plurality of main grooves extending in a tire circumferential direction and/or block-like land portions partitioned by the plurality of main grooves and a plurality of lug grooves intersecting the main grooves in a tread surface. A plurality of protrusions are provided on a surface of the land portions, and at least two types of the protrusions, having different surface areas, are provided. Moreover, at least a majority of the protrusions adjacent to a small protrusion having a relatively small surface area are large protrusions having a relatively large surface area.

A pneumatic tire improved in on-ice performance and on-snow performance in good balance. The pneumatic tire includes a tread portion extending in a tire circumferential direction and forming a ring shape, a pair of sidewall portions on both sides of the tread portion, respectively, and a pair of bead portions on inner sides of the sidewall portions in a tire radial direction, respectively. The tread portion includes a plurality of longitudinal grooves extending in the tire circumferential direction and a plurality of lateral grooves extending in a tire width direction. The longitudinal and lateral grooves define a plurality of block rows each including a plurality of blocks. Each of the plurality of blocks included in at least one of the block rows includes at least three closed grooves including at least one first closed groove and at least one second closed groove.

Growing community of inventors

Hiratsuka, Japan

Hiroshi Furusawa