Abstract: A spinning forming method includes a first forming step and a second forming step, in each of which a plate fixed to a main shaft is formed while being rotated. In the first forming step, a processing tool is brought into contact with a first main surface of the plate to form a first level-changing portion extending from the first main surface toward a second main surface. In the second forming step, the processing tool is brought into contact with the second main surface at an outer peripheral side of the first level-changing portion to form a second level-changing portion extending in an opposite direction to the first level-changing portion.

Abstract: A spinning forming apparatus shapes a plate while rotating the plate around a rotational axis. The spinning forming apparatus includes: a holding member to which the plate is attached and which rotates the plate around the rotational axis; a processing tool configured to contact a first main surface of the plate to process and shape the plate; and a heater configured to heat the plate. The heater is arranged at the opposite side of the processing tool across the plate. The heater locally heats a position of a second main surface of the plate opposite to the first main surface, the position being located on a circumference around the rotational axis, the circumference being defined by a position, with which the processing tool contacts, of the plate.

Abstract: A spinning thickening forming method is a method of, while rotating a plate including a center portion fixed to a fixing jig, increasing a thickness of a peripheral portion of the plate. Specifically, while locally heating the peripheral portion of the plate such that at least a portion of the plate which is adjacent to the fixing jig maintains stiffness, a forming roller is pressed against the peripheral portion of the plate to compress the peripheral portion in at least a direction perpendicular to a thickness direction of the peripheral portion.

Abstract: A spinning thickening forming method is a method of, while rotating a plate including a center portion fixed to a fixing jig, increasing a thickness of a peripheral portion of the plate. Specifically, while locally heating the peripheral portion of the plate such that at least a portion of the plate which is adjacent to the fixing jig maintains stiffness, a forming roller is pressed against the peripheral portion of the plate to compress the peripheral portion in at least a direction perpendicular to a thickness direction of the peripheral portion.

Abstract: An object of the present invention is to reduce heat transferred from a plate through a receiving jig to a rotating shaft in a spinning forming device. A spinning forming device includes: a receiving jig supporting a central portion of a plate to be formed; a rotating shaft to which the receiving jig is attached; a heater configured to heat a transform target portion of the plate by induction heating; and a processing tool configured to press the transform target portion to transform the plate. The receiving jig is configured to suppress heat transfer from the plate to rotating shaft.

Abstract: A spinning forming method includes a first forming step and a second forming step, in each of which a plate fixed to a main shaft is formed while being rotated. In the first forming step, a processing tool is brought into contact with a first main surface of the plate to form a first level-changing portion extending from the first main surface toward a second main surface. In the second forming step, the processing tool is brought into contact with the second main surface at an outer peripheral side of the first level-changing portion to form a second level-changing portion extending in an opposite direction to the first level-changing portion.

Abstract: A spinning forming apparatus shapes a plate while rotating the plate around a rotational axis. The spinning forming apparatus includes: a holding member to which the plate is attached and which rotates the plate around the rotational axis; a processing tool configured to contact a first main surface of the plate to process and shape the plate; and a heater configured to heat the plate. The heater is arranged at the opposite side of the processing tool across the plate. The heater locally heats a position of a second main surface of the plate opposite to the first main surface, the position being located on a circumference around the rotational axis, the circumference being defined by a position, with which the processing tool contacts, of the plate.

Abstract: A swingarm assembly (12) for use in motorcycles for supporting a motorcycle rear wheel (13) includes left and right arms (23L, 23R) and a connecting member (24) by which the left and right arms (23L, 23R) are connected together. At least the arms (23L, 23R) are products of magnesium alloy that are formed by an extrusion technique or a drawing technique.

Abstract: A titanium alloy tappet that is slidable at a high speed is provided by covering shortcomings of lightweight and high-strength titanium alloy. A surface 1A of at least a slidable portion of the tappet 1 for use with a valve system is subjected to a carburizing process.

Abstract: A swingarm assembly (12) for use in motorcycles for supporting a motorcycle rear wheel (13) includes left and right arms (23L, 23R) and a connecting member (24) by which the left and right arms (23L, 23R) are connected together. At least the arms (23L, 23R) are products of magnesium alloy that are formed by an extrusion technique or a drawing technique.

Abstract: A titanium alloy tappet that is slidable at a high speed is provided by covering shortcomings of lightweight and high-strength titanium alloy. A surface 1A of at least a slidable portion of the tappet 1 for use with a valve system is subjected to a carburizing process.