| 摘要 |
OBJECT OF THE INVENTION: The invention provides a low-cost hollow poppet valve comprising a thin cap portion welded to a thin fillet portion. The poppet valve has a superb weight versus strength characteristic and a good heat resisting configuration to protect the seat-abutment portion of the fillet portion against welding heat applied to the fillet portion during welding. MEANS FOR ACHIEVING THE OBJECT A hollow poppet valve of the invention has:
a stem portion (12) provided at one end thereof with a tip portion (12) ; a cap portion (16); and a flared fillet portion (18) formed between the stem portion and the cap portion (16), wherein at least a part of the stem portion (12) that connects to the fillet portion (18) is a thin hollow cylindrical member (11), and the cap member (17) is welded to the fillet portion (18). The cap member 17 is thin and has an arcuate axial cross section. It is laser-beam welded to the seat-abutment portion (19) formed at the open end of the fillet portion (18) such that a weld bead (20) is formed along the inner periphery of the interface F of the mated ends of the members (17) and (19).
Since welding is done instantly by a laser beam having a small beam diameter, welding heat has little influence on the seat-abutment portion (19). The weld bead (20) adds an extra weld depth to the weld, which increases the modulus of section of the welded regions of the cap member (17) and the fillet portion (18) and enhances their welding strength, thereby increasing the rigidity (mechanical strength) of the entire hollow poppet valve (10). |
