Patent ID: 9447711
Filing Date: 2016-09-20
CPC Classification: B21D,B21K,B23K,B23P,F01L,Y10T

Claim Text:
1. A hollow engine valve, comprising: a hollow shaft portion sealed at one end; and a valve head portion of a single-piece material attached to another end of the hollow shaft portion; the single-piece material being a material having heat resistance comparable to or better than the heat resistance of a material for the hollow shaft portion; the valve head portion comprising a cylindrical barrel section and a diameter-increased section at one end of the barrel section, the diameter-increased section including a bottom section; a valve head portion hollow hole opening at a side attached to the hollow shaft portion, the valve head portion hollow hole having a first inner surface, at the diameter-increased section, having an inner diameter that increases as the first inner surface extends toward the bottom section, and a second inner surface at the bottom of the valve head portion hollow hole; and the maximum diameter of the valve head portion hollow hole being larger than a maximum outer diameter of the hollow shaft portion; and the first inner surface and the second inner surface forming a single continuous curved surface.