Spring load adjusting method

A method for adjusting spring load comprising;

• a step for preparing a spring load adjusting device, which includes;
• a spring member;
• a female screw member of a cylindrical shape having a female screw formed at its inner peripheral surface, wherein the female screw member has a swaged-claw forming portion at its axial end in a press direction for pushing the spring member;
• and
• an adjust screw member having a male screw formed at its outer peripheral surface and engaged with the female screw, wherein the adjust screw member adjusts the spring load for the spring member depending on a relative position of the adjust screw member with respect to the female screw member in the press direction;
• a step for preparing multiple swaging punches for plastically deforming the swaged-claw forming portion and forming a swaged claw plastically deformed to an axial end surface of the adjust screw member in the press direction, wherein each of the swaging punches has a punching portion to be brought into contact with the swaged-claw forming portion and a punching area of the punching portion differs from the swaging punch to the swaging punch;
• a step for adjusting the spring load for the spring member by adjusting the relative position of the adjust screw member with respect to the female screw member in the press direction;
• a step for selecting one of the swaging punches to be used for forming the swaged claw in a way that,
• when a press-direction distance in the press direction between an axial end surface of the swaged-claw forming portion and the axial end surface of the adjust screw member is smaller than a predetermined distance range, the swaging punch having a large punching area is selected, wherein the large punching area is larger than a punching area of another swaging punch which is selected when the press-direction distance is larger than the predetermined distance range;
• and
• a step for applying a predetermined swaging load to the swaging punch selected in the above step and press forming the swaged claw, wherein the adjust screw member is pushed by the swaged claw in the press direction to the spring member.