Poppet valve and method for manufacturing same
AssigneeNittan Valve Co., Ltd.
InventorsMaiku Mikami, Kazunori Kurahashi
Life of this patent
Estimating the term…
Abstract
A method for manufacturing a poppet valve 10 from an intermediate valve products is disclosed. The intermediate valve products have an intermediate valve head 14′ with a pressing protrusions 15. A peak 15a of the pressing protrusions 15 is located in a normal direction X2 of the seat surface N, which is positioned on a normal line X2 passing a reference point P3 set on a line segment K connecting a base point P1 in an inner side and a base point P2 in an outer side of the seat surface N; a position of the reference point P3 is set such that a relation between a length L1 from the base point P1 to the reference point P3 and a length L2 from the base point P2 to the reference point P3 meets a formula of L1/L2≤0.5.
Claims7
A method for manufacturing a poppet valve, in which a valve head provided in one end of a valve stem in a longitudinal direction has a seat surface in a direction where an outer diameter is widened toward the one end, by forging an intermediate valve product of the poppet valve, wherein:
- the intermediate valve product of the poppet valve is provided with a large diameter part as the valve head in the one end of the valve stem in the longitudinal direction, wherein the large diameter part is provided with a pressing protrusions in a region serving as the seat surface after forging, the pressing protrusions having a peak positioned in a region in a normal direction of the seat surface on a basis of the seat surface of the forged valve head;
- the method comprising the steps of:
- in a sectional view, the peak of the pressing protrusions is positioned on a normal line passing a reference point set on a virtual line connecting a base point in an inner diameter side and a base point in an outer diameter side of the seat surface;
- and
- as viewed in an axial direction of a center line of the valve stem, a position of the reference point is set such that a relation between a length (L1) from the base point in the inner diameter side to the reference point and a length (L2) from the base point in the outer diameter side to the reference point meets the following formula (1):
- 0<L1/L2≤0.5 1)
- providing a pressing die and a supporting die arranged to face with each other in the center line;
- supporting the intermediate valve product of the poppet valve by the supporting die in a state of causing the pressing protrusions to abut on a pressing surface of the supporting die between the pressing die and the supporting die, the pressing surface having a shape corresponding to the seat surface;
- thereafter moving the pressing die in a direction of approaching the supporting die in the center line direction to plastic-deform a region of the pressing protrusions held between the pressing die and the supporting die in the center line direction;
- and
- thereby forming the seat surface.
Dependencies are inferred from the claim text.