Abstract: A spinning apparatus for decreasing by spinning a thickness of a portion of a tube material having a uniform thickness except at a first axial end portion is disclosed. The spinning apparatus includes a spindle-side chuck having a conical concavity and a mandrel. The mandrel has a mandrel-side chuck formed in a form of a conical convexity corresponding in configuration to the conical concavity of the spindle-side chuck and a cylindrical portion for supporting the tube material. The spinning apparatus further includes a spinning roll for decreasing the thickness of the tube material by pressing the spinning roll against the tube material when the tube material is supported by the cylindrical portion of the mandrel.

Abstract: A multi-piece rim structure for a wheel includes a rim base 10, a bead seat ring 20 (ring member) and a lock ring 30. The bead seat ring 20 receives a load in a radial direction and an axial direction from a bead portion of a tire. An annular ridge 35 of the lock ring 30 can be received in an annular lock ring groove 15 of the rim base 10. A receiving groove 15a is formed in an inner surface of the lock ring groove 15 of the rim base 10. A sacrificial anticorrosion material 80 is embedded in the receiving groove 15a. The sacrificial anticorrosion material 80 includes metal such as zinc and aluminum that has a greater ionization tendency than iron that is a base material of the rim base 10 and the lock ring 30. Corrosion of the rim base 10 and the lock ring 30 can be suppressed by ionization of the sacrificial anticorrosion material 80.

Abstract: A spinning apparatus for decreasing by spinning a thickness of a portion of a tube material having a uniform thickness except at a first axial end portion is disclosed. The spinning apparatus includes a spindle-side chuck having a conical concavity and a mandrel. The mandrel has a mandrel-side chuck formed in a form of a conical convexity corresponding in configuration to the conical concavity of the spindle-side chuck and a cylindrical portion for supporting the tube material. The spinning apparatus further includes a spinning roll for decreasing the thickness of the tube material by pressing the spinning roll against the tube material when the tube material is supported by the cylindrical portion of the mandrel.

Abstract: A multi-piece rim structure for a wheel includes a rim base 10, a bead seat ring 20 (ring member) and a lock ring 30. The bead seat ring 20 receives a load in a radial direction and an axial direction from a bead portion of a tire. An annular ridge 35 of the lock ring 30 can be received in an annular lock ring groove 15 of the rim base 10. A receiving groove 15a is formed in an inner surface of the lock ring groove 15 of the rim base 10. A sacrificial anticorrosion material 80 is embedded in the receiving groove 15a. The sacrificial anticorrosion material 80 includes metal such as zinc and aluminum that has a greater ionization tendency than iron that is a base material of the rim base 10 and the lock ring 30. Corrosion of the rim base 10 and the lock ring 30 can be suppressed by ionization of the sacrificial anticorrosion material 80.

Abstract: The present invention provides a magnesium-based composite material that can achieve excellent performance such as high tensile strength not only at ordinary temperature but also at high temperature. The magnesium-based composite material of the present invention is Al2Ca-containing magnesium-based composite material, wherein said composite material is obtained by a solid-phase reaction of an aluminum-containing magnesium alloy and an additive, said additive being calcium oxide, and said composite material contains Al2Ca formed in the solid-phase reaction. In the magnesium-based composite material, CaO, in combination with Al2Ca, can be dispersed.

Abstract: The present invention provides a magnesium-based composite material that can achieve excellent performance such as high tensile strength not only at ordinary temperature but also at high temperature. The magnesium-based composite material of the present invention is Al2Ca-containing magnesium-based composite material, wherein said composite material is obtained by a solid-phase reaction of an aluminum-containing magnesium alloy and an additive, said additive being calcium oxide, and said composite material contains Al2Ca formed in the solid-phase reaction. In the magnesium-based composite material, CaO, in combination with Al2Ca, can be dispersed.