Patents by Inventor Takahiro Yamakawa

Takahiro Yamakawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11312632
    Abstract: Provided is a tungsten carbide powder satisfying such a condition that when the Fsss particle size thereof is represented by a (?m) and the BET particle size thereof converted from the BET specific surface area is represented by b (?m), a is 0.40 ?m or more and 1.50 ?m or less, and b/a is 0.17 or more and 0.35 or less.
    Type: Grant
    Filed: October 12, 2017
    Date of Patent: April 26, 2022
    Assignee: A.L.M.T. Corp.
    Inventors: Takehiko Hayashi, Tomoyuki Ishida, Takahiro Yamakawa
  • Patent number: 11267293
    Abstract: A pneumatic tire includes at least four circumferential main grooves that extend in a tire circumferential direction; and at least five land portions defined by the circumferential main grooves. The center land portion and the left and right second land portions each include through lug grooves that are inclined at a predetermined inclination angle with respect to the tire lateral direction and extend through the land portion in the tire lateral direction. The through lug grooves located in the center land portion and the through lug grooves located in the left and right second land portions extend in the tire lateral direction inclined in opposite directions to each other. At least one groove wall of each of the through lug grooves located in the left and right second land portions include a step-shaped bent portion that bends in the tire circumferential direction in a plan view of a tread.
    Type: Grant
    Filed: February 9, 2017
    Date of Patent: March 8, 2022
    Inventor: Takahiro Yamakawa
  • Patent number: 11173748
    Abstract: A pneumatic tire includes: a main groove extending in a tire circumferential direction disposed on a shoulder region of a tread portion; lug grooves extending from the main groove toward an outer side and reaching a side wall portion; and blocks demarcated by the main groove and lug grooves. An edge on an innermost side in a tire radial direction of the blocks is positioned more on an outer side in the tire radial direction than a tire maximum width position, and a ratio of an orthogonal distance from a ground contact end position to the edge on an innermost side in the tire radial direction of the blocks is 0.2 or more. Recessed portions each having a closed periphery are provided in a side region more on an outer side in a tire width direction than the ground contact end of the blocks.
    Type: Grant
    Filed: January 12, 2017
    Date of Patent: November 16, 2021
    Inventor: Takahiro Yamakawa
  • Publication number: 20200346935
    Abstract: Provided is a tungsten carbide powder satisfying such a condition that when the Fsss particle size thereof is represented by a (?m) and the BET particle size thereof converted from the BET specific surface area is represented by b (?m), a is 0.40 ?m or more and 1.50 ?m or less, and b/a is 0.17 or more and 0.35 or less.
    Type: Application
    Filed: October 12, 2017
    Publication date: November 5, 2020
    Applicant: A.L.M.T. Corp.
    Inventors: Takehiko HAYASHI, Tomoyuki ISHIDA, Takahiro YAMAKAWA
  • Publication number: 20190233923
    Abstract: A rod includes a first rod section occupying a predetermined region in a longitudinal direction, and a second rod section occupying a region different from the first rod section in the longitudinal direction. The first rod section has composition including A% by mass of cobalt, 0 to 1% by mass of chromium, 0 to 0.5% by mass of vanadium, and remainder of tungsten carbide and unavoidable impurities. The second rod section has composition including B% by mass of cobalt, 0 to 1% by mass of chromium, 0 to 0.5% by mass of vanadium, and remainder of tungsten carbide and unavoidable impurities. Contents of cobalt in the first rod section and the second rod section satisfy a relationship of 1% by mass?B<A?20% by mass. The second rod section has a length of 10 to 1000% with respect to the first rod section in the longitudinal direction.
    Type: Application
    Filed: February 28, 2017
    Publication date: August 1, 2019
    Inventors: Takahiro Yamakawa, Eiji Yamamoto, Hiroaki Gotou, Yoshimitsu Sawazono, Katsuya Uchino
  • Patent number: 10286733
    Abstract: A tread pattern of a pneumatic tire includes two outer circumferential main grooves and two inner circumferential main grooves. Each of the two inner circumferential main grooves comprises a first groove wall and a second groove wall facing the first groove wall. The first groove walls include first oblique wall elements that extend obliquely outward in a tire width direction and second oblique wall elements that extend obliquely inward in the tire width direction and extend for a shorter length than the first oblique wall elements. The second groove walls include third oblique wall elements that extend obliquely inward in the tire width direction and fourth oblique wall elements that extend obliquely outward in the tire width direction and extend for a shorter length than the third oblique wall elements.
    Type: Grant
    Filed: January 28, 2014
    Date of Patent: May 14, 2019
    Assignee: The Yokohama Rubber Co., LTD.
    Inventors: Takahiro Yamakawa, Yasutaka Akashi
  • Patent number: 10252577
    Abstract: A tread pattern on a pneumatic tire is provided in regions of two intermediate land portions and has circumferential shallow grooves extending in the tire circumferential direction. An orientation of a groove inclination inclined with respect to a first direction in the tire circumferential direction of lug grooves provided in a region of one intermediate land portion, is the same as an orientation of a groove inclination inclined with respect to a second direction opposite to of the first direction of the tire circumferential direction of lug grooves provided in a region of another intermediate land portion, and the lug grooves provided in the respective regions of the intermediate land portions are bent so that the groove inclination approaches the tire circumferential direction at positions of intersection with the circumferential shallow grooves.
    Type: Grant
    Filed: December 30, 2014
    Date of Patent: April 9, 2019
    Assignee: The Yokohama Rubber Co., LTD.
    Inventors: Yasutaka Akashi, Takahiro Yamakawa
  • Publication number: 20190023080
    Abstract: A pneumatic tire includes at least four circumferential main grooves that extend in a tire circumferential direction; and at least five land portions defined by the circumferential main grooves. The center land portion and the left and right second land portions each include through lug grooves that are inclined at a predetermined inclination angle with respect to the tire lateral direction and extend through the land portion in the tire lateral direction. The through lug grooves located in the center land portion and the through lug grooves located in the left and right second land portions extend in the tire lateral direction inclined in opposite directions to each other. At least one groove wall of each of the through lug grooves located in the left and right second land portions include a step-shaped bent portion that bends in the tire circumferential direction in a plan view of a tread.
    Type: Application
    Filed: February 9, 2017
    Publication date: January 24, 2019
    Inventor: Takahiro Yamakawa
  • Publication number: 20190016179
    Abstract: A pneumatic tire includes: a main groove extending in a tire circumferential direction disposed on a shoulder region of a tread portion; lug grooves extending from the main groove toward an outer side and reaching a side wall portion; and blocks demarcated by the main groove and lug grooves. An edge on an innermost side in a tire radial direction of the blocks is positioned more on an outer side in the tire radial direction than a tire maximum width position, and a ratio of an orthogonal distance from a ground contact end position to the edge on an innermost side in the tire radial direction of the blocks is 0.2 or more. Recessed portions each having a closed periphery are provided in a side region more on an outer side in a tire width direction than the ground contact end of the blocks.
    Type: Application
    Filed: January 12, 2017
    Publication date: January 17, 2019
    Applicant: The Yokohama Rubber Co., Ltd.
    Inventor: Takahiro YAMAKAWA
  • Publication number: 20180056728
    Abstract: A pneumatic tire includes inner land portions, formed between a center main groove and outer main grooves on both sides of the center main groove, which are divided into blocks by sub-grooves. A pair of the sub-grooves positioned on both sides of the center main groove is inclined in the same direction with respect to the tire width direction, disposed such that openings on the center main groove side overlap in the tire circumferential direction, and the circumferential components of the sub-grooves are continuous throughout the tire circumference. A groove width of the sub-grooves changes at a middle portion in the length direction such that the sub-grooves include a narrow width section positioned on the outer main groove side and have a groove width W1 that is relatively small, and a wide section positioned on the center main groove side and having a groove width W2 that is relatively large.
    Type: Application
    Filed: February 18, 2016
    Publication date: March 1, 2018
    Inventor: Takahiro Yamakawa
  • Publication number: 20170361659
    Abstract: Provided is a pneumatic tire having plurality of compound grooves, each including a lateral groove having a first end that communicates with a main groove on one side thereof and a second end that terminates inside a land portion, and further including a sipe that extends from the second end of the lateral groove to the main groove on the other side thereof, are formed at an interval in a tire circumferential direction in at least one row of the land portions positioned inside a center region. The compound grooves are disposed so that an opening direction of the lateral grooves relative to the main grooves alternatingly reverses in the tire circumferential direction. The lateral grooves each include a broad width portion and a narrow width portion.
    Type: Application
    Filed: November 25, 2015
    Publication date: December 21, 2017
    Inventor: Takahiro YAMAKAWA
  • Publication number: 20170320360
    Abstract: A pneumatic tire includes four main grooves defining a central land portion, intermediate land portions, and outer land portions. Compound grooves including lateral grooves communicate with the main groove and terminate inside a land portion, and including sipes extending from the lateral grooves to the main groove, are formed at an interval in the tire-circumferential direction in the central land portion or an intermediate land portion. An opening direction of the lateral grooves relative to the main grooves alternatingly reverses in the tire circumferential direction. The lateral grooves include a broad width portion that opens to the main groove and extends at a constant groove width, and a narrow width portion positioned between the broad width portion and the sipe and extends at a constant groove width narrower than the broad width portion.
    Type: Application
    Filed: November 25, 2015
    Publication date: November 9, 2017
    Inventor: Takahiro Yamakawa
  • Patent number: 9764599
    Abstract: In a pneumatic tire, shoulder blocks are formed with one of two types of values for block width measured in the tire circumferential direction. A cross-sectional shape of a tread ground contact edge of the shoulder blocks with the smaller block width value when sectioned in a plan that includes a tire axial center is formed with a squared portion formed by a curved line having a radius of curvature of 10 mm or less, or is formed with a squared portion taper cut along a straight line having a length of 10 mm or less. A cross-sectional shape of a tread ground contact edge of the shoulder blocks with the larger block width value when sectioned in the plan that includes the tire axial center is formed with a rounded portion formed by a curved line having a radius of curvature of from 30 mm to 60 mm inclusive.
    Type: Grant
    Filed: August 27, 2014
    Date of Patent: September 19, 2017
    Assignee: The Yokohama Rubber Co., LTD.
    Inventor: Takahiro Yamakawa
  • Patent number: 9662941
    Abstract: Provided is a pneumatic tire with a tread pattern that includes two first circumferential main grooves, shoulder land portions, shoulder lug grooves, shoulder sipes, and narrow circumferential grooves, the shoulder lug grooves being closed off midway in the region of the shoulder land portions without connecting with the first circumferential main grooves and including first regions and second regions that are disposed in the regions closer to the first circumferential main grooves than the first regions and have a groove depth that is less than that of the first regions. The shoulder sipes are connected with the second regions and extend toward the first circumferential main grooves. The narrow circumferential grooves extend in the tire circumferential direction and have a groove width that is less than the groove width of the shoulder lug grooves. The narrow circumferential grooves intersect with the second regions of the shoulder lug grooves.
    Type: Grant
    Filed: March 6, 2014
    Date of Patent: May 30, 2017
    Assignee: The Yokohama Rubber Co., LTD.
    Inventor: Takahiro Yamakawa
  • Publication number: 20160214438
    Abstract: In a pneumatic tire, shoulder blocks are formed with one of two types of values for block width measured in the tire circumferential direction. A cross-sectional shape of a tread ground contact edge of the shoulder blocks with the smaller block width value when sectioned in a plan that includes a tire axial center is formed with a squared portion formed by a curved line having a radius of curvature of 10 mm or less, or is formed with a squared portion taper cut along a straight line having a length of 10 mm or less. A cross-sectional shape of a tread ground contact edge of the shoulder blocks with the larger block width value when sectioned in the plan that includes the tire axial center is formed with a rounded portion formed by a curved line having a radius of curvature of from 30 mm to 60 mm inclusive.
    Type: Application
    Filed: August 27, 2014
    Publication date: July 28, 2016
    Applicant: The Yokohama Rubber Co., Ltd.
    Inventor: Takahiro Yamakawa
  • Publication number: 20150298508
    Abstract: A tread pattern of a pneumatic tire includes two outer circumferential main grooves and two inner circumferential main grooves. Each of the two inner circumferential main grooves comprises a first groove wall and a second groove wall facing the first groove wall. The first groove walls include first oblique wall elements that extend obliquely outward in a tire width direction and second oblique wall elements that extend obliquely inward in the tire width direction and extend for a shorter length than the first oblique wall elements. The second groove walls include third oblique wall elements that extend obliquely inward in the tire width direction and fourth oblique wall elements that extend obliquely outward in the tire width direction and extend for a shorter length than the third oblique wall elements.
    Type: Application
    Filed: January 28, 2014
    Publication date: October 22, 2015
    Applicant: The Yokohama Rubber Co., LTD.
    Inventors: Takahiro YAMAKAWA, Yasutaka AKASHI
  • Patent number: D749039
    Type: Grant
    Filed: April 17, 2014
    Date of Patent: February 9, 2016
    Assignee: The Yokohama Rubber Co., Ltd.
    Inventors: Takahiro Yamakawa, Hiroshi Tokizaki
  • Patent number: D801261
    Type: Grant
    Filed: July 22, 2016
    Date of Patent: October 31, 2017
    Assignee: THE YOKOHAMA RUBBER CO., LTD.
    Inventors: Takahiro Yamakawa, Hiroshi Tokizaki
  • Patent number: D805468
    Type: Grant
    Filed: July 22, 2016
    Date of Patent: December 19, 2017
    Assignee: THE YOKOHAMA RUBBER CO., LTD.
    Inventors: Takahiro Yamakawa, Yasutaka Akashi
  • Patent number: D807814
    Type: Grant
    Filed: July 22, 2016
    Date of Patent: January 16, 2018
    Assignee: THE YOKOHAMA RUBBER CO., LTD.
    Inventors: Takahiro Yamakawa, Yasutaka Akashi