US Patent 10495139 Ball joint and method for manufacturing ball joint

This ball join includes a ball stud with a spherical ball section and a shaft-shaped shaft section and a holder that rotatably bolds the ball section, and has a machining surface subjected to cutting in a welded portion obtained by welding the ball section and the shaft section, and the machining surface has a curve-shaped first corner section. In addition, a method for manufacturing this ball joint includes a welding step of welding the ball section and the shaft section and a cutting step of forming the machining surface by subjecting the welded portion obtained by welding the ball section and the shaft section to cutting, and the cutting step executes processing including forming the curve-shaped first corner section on the machining surface. Consequently, a ball joint with a large oscillation angle can be obtained.