This torsion beam manufacturing method is a method for manufacturing a torsion beam which is provided with a uniformly shaped closed cross-sectional portion in which a cross section orthogonal to a longitudinal direction is a closed cross section having a substantial V-shape or a substantial U-shape with a pair of ear portions, and a shape changing portion which leads to the uniformly shaped closed cross-sectional portion and in which a shape of the closed cross section changes progressively away from the uniformly shaped closed cross-sectional portion, the torsion beam manufacturing method comprising: thickening to form a pair of thickened portions in at least the shape changing portion by pressurizing each of the pair of ear portions from outside against swelling of the pair of ear portions in a slate where both outer surfaces of each of the pair of ear portions are supported.

To provide a method of manufacturing a shaft for a steering device, the shaft including a spline shaft part to be coupled with an input shaft, a stopper part to be coupled with an output shaft, and an intermediate shaft part that couples the spline shaft part with the stopper part. The method includes: a step of forming a hole part recessed in an axial direction from one end of a pillar-shaped material by forging; and a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction on a portion of the material at which the stopper part is formed and prolonging a length along the axial direction of the hole part at the same time by forging.

A method of assembling an electric power steering assembly includes providing a shaft that extends along a longitudinal axis between a first shaft end and a second shaft end. The method further includes extruding or drawing the shaft through a die to define a spline that extends between the first shaft end and the second shaft end. The spline includes a first tooth having a first tip. The method still further includes applying a sleeve over a portion of the spline, such that the sleeve extends from the second shaft end towards the first shaft end.

A method of assembling an electric power steering assembly includes providing a shaft that extends along a longitudinal axis between a first shaft end and a second shaft end. The method further includes extruding or drawing the shaft through a die to define a spline that extends between the first shaft end and the second shaft end. The spline includes a first tooth having a first tip. The method still further includes applying a sleeve over a portion of the spline, such that the sleeve extends from the second shaft end towards the first shaft end.

To provide a method of manufacturing a shaft for a steering device, the shaft including a spline shaft part to be coupled with an input shaft, a stopper part to be coupled with an output shaft, and an intermediate shaft part that couples the spline shaft part with the stopper part. The method includes: a step of forming a hole part recessed in an axial direction from one end of a pillar-shaped material by forging; and a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction on a portion of the material at which the spline shaft part and the intermediate shaft part are formed, and prolonging a length along the axial direction of the hole part at the same time by forging.

To provide a method of manufacturing a shaft for a steering device, the shaft including a spline shaft part to be coupled with an input shaft, a stopper part to be coupled with an output shaft, and an intermediate shaft part that couples the spline shaft part with the stopper part. The method includes: a step of forming a hole part recessed in an axial direction from one end of a pillar-shaped material by forging; and a step of pressing the material in which the hole part has been formed into a die to perform drawing in a radial direction on a portion of the material at which the spline shaft part and the intermediate shaft part are formed, and prolonging a length along the axial direction of the hole part at the same time by forging.

A method for setting conditions for a shaft diameter enlargement, a shaft diameter enlargement method, and a shaft diameter enlargement apparatus are provided. A controller of the shaft diameter enlargement apparatus controls a compressing section, a bending section, and a rotating section to enlarge an intermediate portion of a shaft workpiece to have a predetermined outer diameter by rotating the shaft workpiece about its axis with axial compressive force a bending angle being applied to the intermediate portion. The controller determines whether the shaft workpiece is acceptable, based on the number of rotations of die shaft workpiece required for enlarging the intermediate portion to have the predetermined outer diameter or based on an enlargement ratio of the intermediate portion.

A method for setting conditions for a shaft diameter enlargement, a shaft diameter enlargement method, and a shaft diameter enlargement apparatus are provided. A controller of the shaft diameter enlargement apparatus controls a compressing section, a bending section, and a rotating section to enlarge an intermediate portion of a shaft workpiece to have a predetermined outer diameter by rotating the shaft workpiece about its axis with axial compressive force a bending angle being applied to the intermediate portion. The controller determines whether the shaft workpiece is acceptable, based on the number of rotations of die shaft workpiece required for enlarging the intermediate portion to have the predetermined outer diameter or based on an enlargement ratio of the intermediate portion.

A continuously variable transmission includes: a first pulley having a first fixed sheave and a first movable sheave; a first cylinder forming a first oil chamber with the first movable sheave; a second pulley having a second fixed sheave and a second movable sheave; a second cylinder forming a second oil chamber with the second movable sheave; and a transmission belt wound around the first pulley and the second pulley. The first cylinder has a first member that is fixed to a first shaft and a second member that is joined to an outer peripheral portion of the first member. A bearing is interposed between an outer periphery of the first member and an inner periphery of a case. A thickness, in an axial direction, of a portion of the first member that is configured to directly abut against the first movable sheave is larger than a thickness of the second member.

A continuously variable transmission includes: a first pulley having a first fixed sheave and a first movable sheave; a first cylinder forming a first oil chamber with the first movable sheave; a second pulley having a second fixed sheave and a second movable sheave; a second cylinder forming a second oil chamber with the second movable sheave; and a transmission belt wound around the first pulley and the second pulley. The first cylinder has a first member that is fixed to a first shaft and a second member that is joined to an outer peripheral portion of the first member. A bearing is interposed between an outer periphery of the first member and an inner periphery of a case. A thickness, in an axial direction, of a portion of the first member that is configured to directly abut against the first movable sheave is larger than a thickness of the second member.