A method for manufacturing an engine poppet valve having a valve head portion and a stem portion made integral by way of a neck portion that increases in diameter toward a tip end, comprising: a valve head portion manufacturing operation in which hot forging is employed to form a stem/head intermediate product comprising an intermediate stem portion and a valve head portion which is made integral with the intermediate stem portion by way of a neck portion; a stepped stem portion manufacturing operation in which cold drawing in which a part of the intermediate stem portion is inserted in press-fit fashion from a base end portion into a stem member inlet surface and a stem member compressing surface of a hollow circular hole die that has a drawing hole and at which the stem member inlet surface that gradually narrows toward a central axis, and the stem member compressing surface that is continuous with the stem member inlet surface and that has a constant inside diameter which is less than an outside diameter of the intermediate stem portion are provided at least at a portion thereof is employed to cause a stepped stem portion comprising a first stem portion which has been made to be of decreased diameter, a step portion which has been formed by the stem member inlet surface, and a second stem portion in which there is absence of decrease in diameter and which is continuous by way of the step portion with the first stem portion to be formed from the intermediate stem portion; and a joining operation in which a stem end portion having a same outside diameter as the first stem portion is joined to a base end portion of the first stem portion.

At a diameter-decreasing operation during manufacture of a poppet valve, an intermediate stem portion at which a valve head portion and an intermediate stem portion are made integral by way of a neck portion may be inserted between/among diameter-decreasing tools. Application of compressive forces from compressing surfaces of the diameter-decreasing tools may cause a part of the intermediate stem portion to be decreased in diameter and may cause a main body portion of a first stem portion to be formed and may cause formation of a stepped portion which is continuous with the main body portion, and formation, by an absence of decrease in diameter, of a second stem portion which is broader in girth than the main body portion and which is continuous with the neck portion and which is also continuous with the main body portion by way of the stepped portion.

A method for shaping a hollow valve preform of a pull rod (20) includes a structuring bulb (22) which is inserted into the cavity (56) of a shaft portion (44) of a valve preform. The structuring bulb (22) has an outer diameter, and has an outer structuring, whereafter the hollow shaft portion (44) is shaped, wherein at least a portion of an inner diameter of the cavity (56) is reduced below an outer diameter of the structuring bulb (22). The structuring bulb (22) is then pulled out through the shaped shaft portion (44), wherein the outer structuring is at least partially pressed into the surface of the cavity (56).

A block forged swing check valve body includes a fully encapsulated seat ring. The swing check valve body includes a through hole and a chamber having a shelf portion defined by a D-shaped passageway. The shelf portion overlies an annular shoulder that encapsulates the valve seat. Methods for the manufacturing and use thereof are also provided.

A poppet valve device is proposed, comprising a valve stem, a poppet, having a sealing surface and being formed separately from the valve stem, wherein the poppet is actuatable via the valve stem, and wherein, following an imaginary line parallel to a longitudinal direction of the valve stem along the closing direction of the poppet, the sealing surface is passed before a front end of the valve stem is passed.

A method for producing at least one hollow valve for gas exchange may include introducing a bore into a valve shaft and into a valve head to form the at least one hollow valve, measuring a depth of the bore, washing the at least one hollow valve at least once, providing the at least one hollow valve in a retaining device, orienting the retaining device together with the at least one hollow valve with respect to an associated electrode, moving the associated electrode in relation to the at least one hollow valve, inserting the associated electrode into the bore of the at least one hollow valve, enlarging the bore in a region of the valve head by electromechanical machining processes, removing the associated electrode from the at least one hollow valve, rinsing and/or preserving the at least one hollow valve, and measuring a wall thickness of a valve bottom.

An iron-base sintered alloy material includes a matrix phase, Co base inter-metallic compound particles having hardness of 600 to 1200 HV, carbide-type particles having hardness of 400 to 700 HV, and optionally solid-lubricant particles, the particles being dispersed in the matrix phase. A matrix part including the matrix phase and the two kinds of hard-particles contains 0.3 to 1.5% by mass of C, and 10 to 50% by mass of one or more kinds selected from Si, Mo, Cr, Ni, Co, Mn, S, N, V, Ca, F, Mg, and O, the balance being Fe and unavoidable impurities. By dispersing, in the matrix phase, the Co base inter-metallic compound particles having high hardness, and the carbide-type particles having low hardness and low aggressiveness to mated material and increasing mechanical strength, wear-resistance can be improved with low aggressiveness to mated material and high radial crushing strength (350 MPa or more).

With a poppet valve using a coolant, maximum combustion efficiency is realized by adjusting relative values of a heat insulation effect and a heat dissipation effect. From the inside of a head portion (14) to a stem portion (12) of a hollow poppet valve (10) a heat insulating space (S1) and a cooling portion (S2) loaded with a coolant (19), separated from each other by a partition (15), are formed. By properly setting an installation position and a vertical length of the partition (15) according to a type of vehicle for which the valve is used, appropriate heat insulation effect and heat dissipation effect are obtained. Further, by the partition (15), mechanical or thermal strength of the poppet valve in which the heat insulating space (S1) and the cooling portion (S2) are formed is increased.

A method for making a valve stem seal, comprising the steps of providing a metal retainer having a top portion and a body portion. The body portion having a first section and a second section. In a first state, the first section of the body portion is cylindrical and the second section of the body portion is cone shaped. Providing a hollow mold. Inserting the metal retainer into the outer mold piece, inserting the inner mold piece into the metal retainer, and then securing the inner and outer mold pieces to each other. Filling a cavity around the top portion of the metal retainer with an elastomeric compound. Removing the metal retainer and the formed rubber sealing element from the mold pieces, and pressing downward over the formed valve stem seal to compress the second section of the body portion radially inwardly.

A method for supplying inert gas into a poppet valve intermediate and an apparatus for supplying inert gas are provided that are capable of properly filling the inert gas without waste into the poppet valve intermediate of any size. After a negative pressure is achieved by suction in an internal space (Win) of a poppet valve intermediate (W) as compared to an ambient pressure (Pa) of the poppet valve intermediate (W), the inert gas is supplied into the internal space (Win) until a pressure (P) of the internal space (Win) reaches the ambient pressure (Ps) of the poppet valve intermediate (W).