Mitsubishi Heavy Industries Limited

Yoshimura Company

Fuji Hollow Valve Inc.

Mitsubishi Heavy Industries Machine Tool Co., Ltd.

Hyoji Yoshimura

Hirokazu Morii

Kenichiro Hirao

Katsumi Nakamura

Takashi Mikogami

Kazutaka Maruyama

Yoshihiro Ishihara

Forming of a valve head portion () of a hollow engine valve (V) comprising a material particularly satisfactory in heat resistance is performed by cold forging. The material with excellent heat resistance is worked to form a valve head portion semifinished product () having a hollow hole (S) whose inner diameter (&#x3c6;) is equal to the maximum inner diameter (&#x3c6;) of a hollow hole (S) of a finished product of the valve head portion (), and having a diameter-increased section () whose maximum outer diameter (&#x3c6;) is equal to the maximum outer diameter (&#x3c6;) of a diameter-increased section () 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 () are necked down by cold forging performed a plurality of times to obtain the finished product of the valve head portion ().

Method for production of valve head portion of hollow engine valve and hollow engine valve

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 () which is provided with a valve main body () in which a hollow hole () is formed along a valve umbrella part () and a hollow shaft part (), wherein a solid round bar () forming the material of the valve main body () is molded to a semi-finished article () by means of a single hot-forging process, the semi-finished article () is subjected to rotary swaging whereby the semi-finished article () is molded into a semi-finished article (), the semi-finished article () is subjected to necking whereby the semi-finished article () is molded into the valve main body (), and a shaft end sealing member () is joined to the end part of the hollow shaft part () of the valve main body ().

Method for producing a hollow engine valve

A method for manufacturing a hollow engine valve includes a step for performing rotational plastic working on a follow engine valve body semifinished product which is configured from a shaft part and a valve umbrella part forming portion connected to the shaft part. A columnar hole part is formed from the shaft part to an enlarged diameter section of the valve umbrella part forming portion to thereby reduce the diameter of the shaft part. A necking step follows the rotational plastic working step, necking the hollow engine valve body semifinished product to thereby reduce the outer diameter and the inner diameter of the shaft part. A sealing step seals the leading end of the shaft part to obtain the hollow engine valve.

Method for manufacturing hollow engine valve

Forming of a valve head portion () 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 () having a hollow hole (S) whose inner diameter (&#x3c6;) is equal to the maximum inner diameter (&#x3c6;) of a hollow hole (S) of a finished product of the valve head portion (), and having a diameter-increased section () whose maximum outer diameter (&#x3c6;) is equal to the maximum outer diameter (&#x3c6;) of a diameter-increased section () 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 () are necked down by cold forging performed a plurality of times to obtain the finished product of the valve head portion (). This method of obtaining the finished product is provided by the present invention.

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.

Method for producing hollow engine valve

Disclosed is a method&#x2014;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 (DDDx, 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)&#x2014;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 S-S) and then inserting the block-shaped solid metallic sodium (Na) into the hollow section (H) of the stem section (S) (step S), the stem section (S) is further drawn (steps Sand S).

Method for producing metallic-sodium-filled engine valve

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 () and an inner cylinder () 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&#xb0; C. (second step).

Method for manufacturing valve umbrella portion of hollow engine valve, press device of valve umbrella portion of hollow engine valve, and hollow engine valve

Provided is a method for producing an engine valve by subjecting a stem portion having a hollow part to a drawing treatment using a series of dies such that the outer diameter and inner diameter of the stem portion become smaller in steps and the stem portion is thereby molded to the desired size, whereby, after the stem portion has been subjected to the drawing treatment until the inner diameter of the hollow part of the stem portion has reached a specific size, sodium metal in the form of a solid block is introduced to the hollow part of the stem portion, and a protective agent made from solid paraffin or naphthalene is also introduced to the hollow part of the stem portion such as to form a barrier between the sodium metal and the atmosphere, after which the stem portion is further subjected to a cold drawing treatment.

Method for producing engine valve in which sodium metal is sealed

Forming of a valve head portion () 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 () having a hollow hole (S) whose inner diameter (&#x3a6;) is equal to the maximum inner diameter (&#x3a6;) of a hollow hole (S) of a finished product of the valve head portion (), and having a diameter-increased section () whose maximum outer diameter (&#x3a6;) is equal to the maximum outer diameter (&#x3a6;) of a diameter-increased section () 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 () are necked down by cold forging performed a plurality of times to obtain the finished product of the valve head portion (). This method of obtaining the finished product is provided by the present invention.

A vane adjustment mechanism, for controlling the quantity of exhaust gas including a base unit having an inner base unit and an outer base unit. The inner base unit ( A) has first and second flanges, and is forced into the outer base unit ( B). A plurality of U-shaped indentations ( ) are spaced at regular angular intervals and each indentation extends from the first flange ( ) to the second flange ( ), so that the U-shaped indentations form vane shaft holes for accommodating the vane lever units ( ) when the inner base unit is inserted into the outer base unit to block the U-shaped indentations in such a way that the vane lever units are free to rotate. A link plate ( ) has U-shaped indentations, in which protrusions of the vane lever units ( ) engage, all along the circumferential edge of the link plate.

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Nagoya, Japan

Hyoji Yoshimura