Patents by Inventor Naoki Tadakuma

Naoki Tadakuma 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).

  • Manufacturing method of suspension spring for car
    Patent number: 6346157
    Abstract: A method for manufacturing a coiled spring having a high fatigue strength to be used for example as a suspension spring of a car using a rod of tensile strength 1910 to 2020 N/mm2 and diameter 8 to 17 mm. In a cold coiling step, the rod is formed into a coil. Annealing is then carried out to remove strains having arisen inside the coil during the coiling step. A hot setting step of utilizing surplus heat from the annealing step and applying a predetermined load to the coil to compress it for a predetermined time is then carried out. After that, multi-stage shot peening is carried out on the coil.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: February 12, 2002
    Assignees: Showa Corp., Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Yoshiyuki Takezawa, Kazuo Ichiki, Naoki Tadakuma, Takahiro Tanae, Hiroshi Akiyama