Sumitomo Rubber Industries Limited

Masahiro Kishida

Yoshihide Kojima

Naoya Ichikawa

Akihiko Hamada

Masaki Shiraishi

Kohei Takemura

Ikuo Atake

Hiroyuki Kurosawa

Takaichiro Shimokado

A pneumatic tire has a main groove () provided to a tread part (). A groove bottom () includes a protrusion portion () that is convex outward in a tire radial direction. The protrusion portion () continues along the main groove (). The width (W) of the protrusion portion () in a direction perpendicular to a groove center line (G) of the main groove () is 50% to 100% of the groove width (W) of the main groove (). The protrusion portion () juts outward in the tire radial direction from an imaginary groove bottom (A) that connects an inner end (i) of a first groove wall () and an inner end (i) of a second groove wall () in a straight line, and the cross-sectional area of the protrusion portion () is 3% to 15% of the transverse cross-sectional area of the main groove ().

Pneumatic tire

A pneumatic tire comprises a tread portion provided with a plurality of blocks, each of the block having a block wall surface facing a transverse groove inclined at an angle (theta) of from 5 to 40 degrees with respect to the tire axial-direction so as to define an acute-angled corner and an obtuse-angled corner on the block. The block wall surface between the acute-angled corner and the obtuse-angled corner is provided with at least two slits having a width of from 0.3 to 2.0 mm. A distance Pmeasured from the acute-angled corner to one of the at least two slits which is nearest to the acute-angled corner is more than a distance Pmeasured from said obtuse-angled corner to one of said at least two slits which is nearest to the obtuse-angled corner; each distance is measured along the radially outer edge of the block wall surface to the widthwise center of the slit.

A method for tire rolling simulation on mud comprises the steps of modeling a tire using finite elements to build a tire model, modeling a muddy road using finite volumes to build a muddy road model which can exhibit elastoplasticity property and failure property, and executing a numerical simulation in which the tire model is made to roll on the muddy road model in a predetermined condition.

Method for tire rolling simulation on mud

A device and a method for making a tire puncture sealant having a higher concentration of propylene glycol are disclosed, wherein the device comprises: a container having a cylindrical space for a mixed solution of rubber latex and a tackifier; a squirter comprising at least one spout for pouring propylene glycol on the surface of the mixed solution in the container at a rate of 0.01 to 1.0 liter/minute per spout; and an agitator for the mixed solution in the container, comprising a stirring blade rotatable in the mixed solution to cause said surface a current speed of the mixed solution in a range between about 1.0 and about 10.0 meter/second during pouring the propylene glycol.

Tire puncture sealant and method for making

A pneumatic tire comprising a tread portion having tread elements each provided with a sipe, wherein the sipe is open to a upper surface of the tread element, and has an open top end including a zigzag part and a bottom, wherein the sipe comprises: a first portion in which the zigzag part of the open top end extends to a side of the bottom in a state of being inclined to one side of a longitudinal direction of the sipe; a second portion connected to an inner side in a radial direction of the first portion, and in which the zigzag part extends to the side of the bottom in a state of being inclined in an opposite direction to the first portion; and a third portion connected to an inner side in a radial direction of the second portion, and in which the zigzag part extends to the side of the bottom in a state of being inclined in an opposite direction to the second portion, and the sipe satisfies the following relation (1):&#x3b1;1&#x3e;&#x3b1;2&#x3e;&#x3b1;3&#x2003;&#x2003;(1) where &#x3b1;is a ratio (a/h) between a displacement length aof the first portion and a length hin a radial direction of the first portion, &#x3b1;is a ratio (a/h) between a displacement length aof the second portion direction and a length hin a radial direction of the second portion, and &#x3b1;is a ratio (a/h) between a displacement length aof the third portion and a length hin a radial direction of the third portion.

Pneumatic tire with tread having zigzag sipes

A method for tire rolling simulation on sand comprises the steps of modeling a tire using finite elements to build a tire model, modeling a sandy road using finite volumes to build a sandy road model which can exhibit elastoplasticity with both elastic and plastic properties, and executing a numerical simulation in which the tire model is made to roll on the sandy road model in a predetermined condition.

Method for tire rolling simulation on sand

A pneumatic tire comprising a tread portionhaving blockseach provided with sipeings, wherein each sipeinghas an opening having a zigzag portionin its opening edge shape J at a block surface S, and opposing wall surfaces in the depth direction Ff which have zigzag displacement portions which are displaced toward one end of the longitudinal direction Fn of the opening and the other end and which are alternately repeated while substantially maintaining the opening edge shape J in the depth direction, and wherein each sipeingsatisfies the following equations,W&#x2267;W&#x2003;&#x2003;(1)and&#xd7;W&#x2267;W&#x3e;&#x2003;&#x2003;(2)in which WWand Ware displacement amounts of a zigzag displacement portionU located on the block surface side, a zigzag displacement portionL located on the sipeing bottom side and an intermediate zigzag displacement portionM in a direction Fv perpendicular to the longitudinal direction Fn, respectively.

Pneumatic tire with blocks having zigzag sipes

A tire puncture sealant comprises a latex of natural rubber, an emulsion of a tackifier and an antifreezing agent, wherein the tackifier is an aromatic modified terpene resin, and given that the total A+B+C of the solid content A of the natural rubber latex, the solid content B of the tackifier emulsion and the content C of the antifreezing agent is 100 weight %, the solid content A of the natural rubber latex is in a range of from 30 to 60 weight %, the solid content B of the tackifier emulsion is in a range of from 10 to 30 weight %, and the content C of the antifreezing agent is in a range of from 20 to 50 weight %.

Tire puncture sealant

A puncture sealing agent for a tire is at least comprising a rubber latex, an adhesive agent, and an antifreezing agent, wherein propylene glycol is used as the antifreezing agent, and further the ratio of the propylene-glycol to the total weight of the puncture sealing agent is set from 20 to 40% by weight.

Puncture sealing agent for a tire, and process for producing the same

A tire puncture sealant set comprises a bottle having a body and a threaded neck portion provided with an outlet, a puncture sealant in the bottle, an inside plug put into the outlet, an outer cap screwed onto the neck portion for covering the inside plug, an injector replaceable with the outer cap, a side wall of the body having a triple layered structure of an inner layer, an outer layer and a middle layer therebetween made of a gas barrier resin so that the body is squeezable by hand, the inside plug provided with a breakable partition wall separating the inside of the bottle from the outside, the injector comprising an adapter cap to be screwed onto the neck portion, a sticking pipe for piercing the breakable partition wall into the inside of the bottle, and a hose for injecting the sealant into a pneumatic tire.

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Kobe, Japan

Masahiro Kishida