Nittan Valve Co., Ltd.

Maiku Mikami

Kazunori Kurahashi

A method for manufacturing a poppet valvefrom an intermediate valve products is disclosed. The intermediate valve products have an intermediate valve head' with a pressing protrusions. A peakof the pressing protrusionsis located in a normal direction Xof the seat surface N, which is positioned on a normal line Xpassing a reference point Pset on a line segment K connecting a base point Pin an inner side and a base point Pin an outer side of the seat surface N; a position of the reference point Pis set such that a relation between a length Lfrom the base point Pto the reference point Pand a length Lfrom the base point Pto the reference point Pmeets a formula of L/L&#x2264;0.5.

Poppet valve and method for manufacturing same

A method of forming a poppet valve having a stem, a valve head and a valve seat while concurrently maintaining compressive residual stress without grain coarsening on both the valve body and the valve seat. The method includes forming a rounded cladded part on the valve head of the poppet valve by welding and forming a valve seat surface at a predetermined aperture angle and cutting the cladded part to form a smooth surface which is subjected to uniform contact pressure at a temperature less than the recrystallization temperature of the base material or cladding material, whichever is lower, to enhance the durability of the valve seat.

Poppet valve with a formed seat, and method of making

A method of manufacturing a valve for an internal combustion engine, comprises: (i) a primary step of forging a bulging portion at one end of a rod material to form a generally disk-shape valve head of the valve having a tapered periphery; (ii) an thickness adjustment step of machining an excessively thick portion of the valve head; and (iii) a secondary step of forging a peripheral region of the valve head to create radial slip deformations therein to form a valve face of the valve head. In the step of thickness adjustment, only the front end of the disk-shape valve head is machined without harming dense grain flow lines induced in the tapered face () in the primary forging while advantageously saving the valve material and reducing thickness adjustment time. In the secondary forging, the hardness of the valve face is further enhanced.

Method of manufacturing a valve for an internal combustion engine

A method of manufacturing a valve () is provided, in which an intermediate valve product having a generally disk-shape valve head is formed by a die unit (). The valve head is then machined to have a proper thickness and a tapered face on the periphery of the disk-shape valve head. The valve head is repeatedly forged in secondary forging by means of a die unit () equipped with a die () and a press punch () while angularly displacing the tapered face relative to the die () through a predetermined angle. Since the die () has protruding pressing sections and grooves () along the circumference of the die, a uniformly deformed and hardened valve face () is formed on the valve head.

Growing community of inventors

Hadano, Japan

Maiku Mikami