Abstract: The invention relates to a method for producing a valve body for a hollow valve. Said method comprises the following steps: providing a workpiece, blank or semi-finished product and a forming punch, introducing a protective layer between the workpiece and the forming punch (22) and press forming the workpiece to produce a preform. The invention also relates to a hollow valve produced by means of this method.

Abstract: A hollow valve having optimized interior stem geometry, whose valve stem has surface-enlarging structuring on an inner surface is provided. Also provided is a method for manufacturing a valve body of such a hollow valve, wherein the method comprises: providing a bowl-shaped semi-finished product having an annular wall that surrounds a cavity, and having a base section, followed by lengthening the wall with an inserted, structured mandrel, and lastly, reducing an outer diameter of the annular wall without a mandrel to obtain a predetermined valve stem outer diameter of a valve to be manufactured.

Abstract: A method of manufacturing an engine valve intermediate product with a boss portion formed in integral fashion at an outer circumferential surface at an intermediate location on a stem forming portion. The manufacturing method may comprise a stem retaining operation in which an intermediate location of the stem forming portion is retained by a plurality of intermediate jigs removably installable radially with respect to a center of the stem forming portion, and a base end portion is retained by a base end jig. The manufacturing method may further comprise a stem enlarging operation in which compressive forces are applied from both ends of the intermediate product and the boss portion is formed as the intermediate product is made to rotate and alternating loads that cause tensile forces and compressive forces to act in repeated and alternating fashion at the outer circumferential surface of the stem forming portion are applied.

Abstract: Disclosed is a method for the production of a valve body of a hollow chamber valve, said method comprising: providing a bowl-shaped semi-finished product having an annular wall, which surrounds a hollow chamber, and a bottom portion, followed by a lengthening of the wall and a final reducing of an outer diameter of the annular wall in order to obtain a predetermined valve shaft outside diameter of a valve that is to be produced. Further disclosed is a hollow chamber valve produced by means of said method.

Abstract: A method for the production for a semi-finished valve product (4), includes casting, forging, deep-drawing, pressing and/or drop-welding of one or several metal material into a semi-finished valve product (4) that corresponds to a circle segment of a valve cut open in the axial direction. A valve is produced by welding together at least two semi-finished valve products (4) into an internally cooled valve, with the weld running in the axial direction of the valve.

Abstract: The present disclosure provides a method for manufacturing a work piece, such as fasteners or flange nuts. The method produces a work piece with a thickened wall. This can be accomplished using a plurality of successive stamping dies to reduce the diameter of a cup-shaped feature drawn from a blank, and reforming the cup-shaped feature to a formed shape having a thickened wall. A fastener or flange nut with a thickened wall manufactured by stamping and forming is also disclosed.

Abstract: The present invention provides a hollow engine valve achieving high durability while suppressing an increase in manufacturing cost, and a manufacturing method therefor.

Abstract: Provided is a method of manufacturing a composite metal material which includes a first metal member made of first metal and a second metal member made of second metal having a smaller linear expansion coefficient than first metal. The method includes in the following order: a metal member preparation step of preparing the first metal member made of first metal and a plurality of divided members made of second metal; an assembling step of assembling the respective metal members into an assembled body; and a bonding step of, by applying a first temperature and a first pressure which enable the respective metal materials to be bonded to each other to the assembled body, bonding the plurality of divided members to each other thus forming the second metal member and also of bonding the first metal member and the second metal member to each other.

Abstract: 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 (16a) 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.

Abstract: A method of manufacturing a valve (10) is provided, in which an intermediate valve product having a generally disk-shape valve head is formed by a die unit (20). 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 (40) equipped with a die (42) and a press punch (48) while angularly displacing the tapered face relative to the die (42) through a predetermined angle. Since the die (42) has protruding pressing sections and grooves (46) along the circumference of the die, a uniformly deformed and hardened valve face (16) is formed on the valve head.

Abstract: A method of manufacturing a valve (10) is provided, in which an intermediate valve product having a generally disk-shape valve head is formed by a die unit (20). 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 (40) equipped with a die (42) and a press punch (48) while angularly displacing the tapered face relative to the die (42) through a predetermined angle. Since the die (42) has protruding pressing sections and grooves (46) along the circumference of the die, a uniformly deformed and hardened valve face (16) is formed on the valve head.

Abstract: The present invention provides a method for producing a hollow engine valve, with which the production process can be simplified and the processing precision can be improved. To this end, the present invention provides a method for producing a hollow engine valve (1) which is provided with a valve main body (10) in which a hollow hole (10c) is formed along a valve umbrella part (10a) and a hollow shaft part (10b), wherein a solid round bar (11) forming the material of the valve main body (10) is moulded to a semi-finished article (12) by means of a single hot-forging process, the semi-finished article (12) is subjected to rotary swaging whereby the semi-finished article (12) is moulded into a semi-finished article (13), the semi-finished article (13) is subjected to necking whereby the semi-finished article (13) is moulded into the valve main body (10) , and a shaft end sealing member (20) is joined to the end part of the hollow shaft part (10b) of the valve main body (10).

Abstract: A method for producing a hollow engine valve is disclosed which involves gradually reducing the size of the outer diameter and inner diameter of a hollow shaft of a semi-finished product sequentially inserting the hollow shaft into a plurality of molding holes having different hole shapes so as to gradually extend the length of the hollow shaft, and forming the hollow shaft into a predetermined shape by sequentially performing a drawing process. The semi-finished product is subjected to heat treatment such that the hardness thereof is equal to or less than a predetermined hardness, and the maximum thickness between the hollow shaft and an umbrella portion connected to the bottom edge of the hollow shaft is formed to be thicker than the thickness of the hollow shaft by means of a molding hole of a die which is adjusted to have a specific length and maximum inner diameter.

Abstract: 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 (16a) 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.

Abstract: Disclosed is a method—for producing an engine valve (V) filled with metallic sodium (Na) within by means of: forming a stem section (S), which has a hollow section (H), at an intended size by successively drawing the stem section (S) using dies (D1, D2, Dx, Dx+1, Dn) in a manner so as to causing the size of the outer diameter and the inner diameter of the stem section (S) to contact in a stepwise fashion; and inserting metallic sodium (Na) into the hollow section (H) of the stem section (S)—wherein after drawing the stem section (S) until the inner diameter of the hollow section (H) of the stem section (S) has become a prescribed size (steps S11-S15) and then inserting the block-shaped solid metallic sodium (Na) into the hollow section (H) of the stem section (S) (step S16), the stem section (S) is further drawn (steps S17 and S18).

Abstract: A semi-finished product having a hollow and an expansion diameter portion is manufactured in advance (first step), and a press device for folding an outer cylinder (4) and an inner cylinder (5) around an entire die set (DS) is used, thereby performing drawing with a body of the semi-finished product as the center in a constant temperature atmosphere at any temperature between a room temperature and 870° C. (second step).

Abstract: Forming of a valve head portion (1) of a hollow engine valve (V) comprising a material particularly satisfactory in heat resistance is performed by cold forging. On this occasion, the material with excellent heat resistance is worked to form a valve head portion semifinished product (11) having a hollow hole (S11) whose inner diameter (?11) is equal to the maximum inner diameter (?11) of a hollow hole (S1) of a finished product of the valve head portion (1), and having a diameter-increased section (111) whose maximum outer diameter (?12) is equal to the maximum outer diameter (?12) of a diameter-increased section (1a) of the finished product. Parts of the valve head portion semifinished product other than a central part to a lower part of the diameter-increased section (111) are necked down by cold forging performed a plurality of times to obtain the finished product of the valve head portion (1). This method of obtaining the finished product is provided by the present invention.

Abstract: Forming of a valve head portion (1) of a hollow engine valve (V) comprising a material particularly satisfactory in heat resistance is performed by cold forging. On this occasion, the material with excellent heat resistance is worked to form a valve head portion semifinished product (11) having a hollow hole (S11) whose inner diameter (?11) is equal to the maximum inner diameter (?11) of a hollow hole (S1) of a finished product of the valve head portion (1), and having a diameter-increased section (111) whose maximum outer diameter (?12) is equal to the maximum outer diameter (?12) of a diameter-increased section (1a) of the finished product. Parts of the valve head portion semifinished product other than a central part to a lower part of the diameter-increased section (111) are necked down by cold forging performed a plurality of times to obtain the finished product of the valve head portion (1). This method of obtaining the finished product is provided by the present invention.

Abstract: A method for manufacturing valve seats using a laser cladding process is provided that includes forming a casting material on which the valve seats are to be formed; fabricating a valve seat target position on which laser cladding will be performed, the valve seat target position being provided at a location on the casting material where a valve seat is to be formed; removing an oxidation film formed on the valve seat target position; injecting a metal powder mixture on the valve seat target position, the metal powder mixture being realized through a mixture of two or more metal powders at a predetermined ratio by weight %; and irradiating a laser beam on the metal powder mixture to clad the metal powder mixture on the valve seat target position to thereby form the valve seat.

Abstract: An improved process 30 for making an engine poppet valve 10 provides an unfinished poppet valve 10 with an initial diameter (d1) of a valve head 22 and an initial thickness (t1) of an interface 56 between a seat facing groove 54 and a combustion face 18 of the valve 50 prior to seat facing the valve 50 to prevent burn-through during the welding process 38. Coining 40 the valve head 22 after seat facing 38 decreases the initial thickness (t1) of the interface 56 to a selected thickness (t2) and increases the initial diameter (d1) to a final or desired diameter (d2) of the valve head 22. The method of the present invention eliminates any need for removing excess material and allows for hot forming the seat facing material 58 to reduce machining steps.

Abstract: A bar material is made of an (&agr;+&bgr;) or a near &agr; Ti alloy which comprises a regular &agr; structure, and the end thereof is heated at a temperature above its &bgr; transformation point by an electric forging device to form an enlarged portion. The enlarged portion is immediately formed by hot forging to make a valve head of a poppet valve which is employed in an internal combustion engine. The valve head comprises an acicular &agr; structure which provides higher fatigue and tensile strengths.