Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Kunihiro Yoshida

Kenji Tamura

Junichi Okubo

Masao Hori

Ryusuke Nakano

Sam Soo Hwang

Samsoo Hwang

Tomihiko Fukuyasu

Nobutaka Tanimoto

Kenji Imanishi

Kunihiro Yabuno

Koichiro Ishihara

Yukihiro Ota

Tadashi Matsui

In a pressing step, a first forged product is pressed by a first die, and thereby, a second forged product including a rough flange having a thickness-changing portion is produced. The thickness-changing portion includes a front part protruding frontward from a side of a rough web part and a rear part protruding rearward from the side of the rough web part. Each of the front part and the rear part includes a first part, and a second part that is thicker than the first part and is located farther from the rough web part than the first part. In the pressing step, at least a part of the rough flange that is above or below the web part (thick part) is pressed by the first die, whereby the material of the first forged product in the part is caused to flow frontward and rearward, and the thickness-changing portion is formed.

Front axle beam and production method thereof

The production method disclosed is a method for producing a front axle beam. The production method includes a die forging step and a bending step. The die forging step is a step of forging a steel material with dies to produce a forged product including a rough web part, which is to be formed into a web part, and four plate-shaped rough flange parts protruding frontward and rearward from an upper side and a lower side of the rough web part, respectively. The bending step is a step of pressing at least one specified rough flange part, which is at least one of the four rough flange parts, with a first die to form a bent portion in the specified rough flange part such that the bent portion is bent inward in an up-down direction of the forged product.

Provided is a production method, including a first preforming process for obtaining a first preform from a billet, a second preforming process for obtaining a final preform from the first preform, and a finish forging process for forming the final preform into a finishing dimension of a forged crankshaft. In the first preforming process, a plurality of flat parts are formed by pressing pin-corresponding parts and journal-corresponding parts in a direction perpendicular to an axial direction of the billet. The second preforming process includes: a process of pressing regions to be a plurality of journals with a width direction of the flat part as a pressing direction by using a pair of first dies; and a process of, after starting pressing by the first dies, decentering regions to be a plurality of pins with the width direction of the flat part as a decentering direction by using second dies.

Method for producing forged crankshaft

Provided is a production method, including a first preforming process, a second preforming process, and a finish forging process. In the first preforming process, while a plurality of flat parts are formed, a region to be a second pin is decentered. The second preforming process includes: a process of pressing each region to be a plurality of journals in a pressing direction corresponding to a width direction of the flat part by using a pair of second dies; and a process of, after starting the pressing by the second dies, decentering a region to be a first pin and to be disposed in a first position and a region to be a third pin and to be disposed in a third position from each other in opposite directions with a width direction of the flat part being as a decentering direction by using third dies.

A production method includes a preforming process, a forming process and a finish forging process. In the preforming process, an intermediate preform is formed from a billet. In the forming process, while each of a plurality of rough journals of the intermediate preform is held and pressed vertically by a pair of holding dies, rough pins are decentered in directions perpendicular to the pressing direction by the holding dies and an axial direction of the intermediate preform, and the intermediate preform is pressed in the axial direction of the intermediate preform. In the finish forging process, a final preform is placed such that the directions in which the rough pins are decentered are parallel to a horizontal direction, and the thus placed final preform is pressed vertically by a pair of pressing dies. The production method reduces the risk of occurrence of seams on a forged crankshaft.

A forged crankshaft production method includes a first preforming step, a second preforming step, and a final preforming step. The first pair of dies includes web processing parts to come into contact with portions to be formed into arms and portions to be formed into weights integrated with the arms. Each of the web processing parts includes an arm processing part and a weight processing part. The arm processing part and the weight processing part form a recessed portion, and the width of the open side of the weight processing part becomes greater with increasing distance from the bottom of the recessed portion. Accordingly, in the blank, volume can be distributed between a portion to be formed into an arm and a portion to be formed into a weight integrated with the arm, and the material yield rate can be improved.

A forged crankshaft production method includes a first preforming step, a second preforming step, and a final preforming step. In the first preforming step, sectional areas of portions to be formed into pins and sectional areas of portions to be formed into journals are decreased, whereby flat portions are formed, and the portion to be formed into the pin located at a second position is decentered. In the second preforming step, a portion to be formed into the pin located at a first position is decentered, and a portion to be formed into the pin located at a third position is decentered to a side opposite to the portion to be formed into the pin located at the first position. In a blank obtained thereby, portions to be formed into pins have been reduced and decentered, and the material yield rate can be improved.

In a forming apparatus, movable journal dies and stationary journal dies retain rough journal portions of a preform blank therebetween, and reference crank pin die and movable crank pin dies contact rough crank pin portions thereof, and in this state, the movable journal dies and the movable crank pin dies are moved axially toward the reference crank pin die and the reference crank pin die and the movable crank pin dies are moved in a direction perpendicular to an axial direction. With this, weighted rough arm portions are axially compressed to reduce their thickness to that of weighted arms of a forged crankshaft, and the rough crank pin portions are pressed in the direction perpendicular to the axial direction to increase an amount of eccentricity to that of the crank pins of the forged crankshaft.

Apparatus for forming a blank for finish forging for a forged crankshaft for a three-cylinder engine and method for manufacturing a forged crankshaft for a three-cylinder engine using the same

In a forming apparatus, stationary journal dies (U,B) and movable journal dies (U,B) each hold and retain rough journal portions (Ja) of a preform blank () therebetween, and crank pin dies () contacts rough crank pin portions (Pa) thereof, and in this state, the movable journal dies (U,B) are moved axially toward the stationary journal dies (U,B) and the crank pin dies () are moved in the same axial direction and in an eccentric direction. With this, weighted rough arm portions (Aa) are axially compressed to reduce their thickness to that of weighted arms of a forged crankshaft, and the rough crank pin portions (Pa) are pressed in the eccentric direction to increase the amount of eccentricity to that of the crank pins of the forged crankshaft.

Apparatus for forming a blank for finish forging for a forged crankshaft for a 4-cylinder engine, and method for manufacturing a forged crankshaft for a 4-cylinder engine using the same

In a forming apparatus, movable journal dies and stationary journal dies hold and retain rough journal portions of a preform blank therebetween, and movable crank pin dies contact rough crank pin portions thereof, and in this state, the movable journal dies and the movable crank pin dies are moved axially toward the stationary journal dies and the movable crank pin dies are moved in a direction perpendicular to an axial direction. With this, rough arm portions are axially compressed to reduce their thickness to that of arms of a forged crankshaft, and the rough crank pin portions are pressed in the direction perpendicular to the axial direction to increase an amount of eccentricity to that of the crank pins of the forged crankshaft.

Apparatus for forming a blank for finish forging for a forged crankshaft for a straight-6-cylinder engine and method for manufacturing a forged crankshaft for a straight-6-cylinder engine using the same

A method of manufacturing a die forged crankshaft to be mounted in a two or more cylinder reciprocating apparatus includes: an upsetting step that includes upsetting a billet having a constant cross-sectional area along an entire length thereof to form a blank having an enlarged cross-sectional area at a region between a portion to be formed into a leading crank arm of the crankshaft and a portion to be formed into a trailing crank arm thereof; a die forging step that includes die forging the blank formed in the upsetting step to form a forged blank having a shape of the crankshaft with a flash; and a trimming step that includes trimming the flash from the forged blank formed in the die forging step. This makes it possible to improve the material utilization and to use a billet having a cross-sectional size as small as possible.

Method of manufacturing die forged crankshaft

In a forming apparatus, journal dies hold and retain rough journal portions of a preform blank therebetween, and reference crank pin die and movable crank pin dies contact rough crank pin portions thereof. In this state, the journal dies and the movable crank pin dies are moved axially toward the reference crank pin die and the reference crank pin die and the movable crank pin dies are moved perpendicular to an axial direction. With this, rough crank arm portions are axially compressed to reduce their thickness to that of crank arms of a forged crankshaft, and the rough crank pin portions are pressed perpendicular to the axial direction to increase an amount of eccentricity to that of the forged crankshaft crank pins. Consequently, it is possible to form a blank for finish forging having a shape generally in agreement with a shape of the forged crankshaft for a three-cylinder engine.

In a forming apparatus, stationary journal dies (U,B) and movable journal dies (U,B) each hold and retain rough journal portions (J') of a preform blank () therebetween, and crank pin dies () contacts rough crank pin portions (P&#x2032;) thereof, and in this state, the movable journal dies (U,B) are moved axially toward the stationary journal dies (U,B) and the crank pin dies () are moved in the same axial direction and in an eccentric direction. Rough crank arm portions (A&#x2032;) are axially compressed to reduce their thickness to that of crank arms of a forged crankshaft, and the rough crank pin portions (P&#x2032;) are pressed in the eccentric direction to increase eccentricity to that of the crank pins of the forged crankshaft. Consequently, it is possible to form a blank for finish forging having a shape generally in agreement with the shape of the forged crankshaft.

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Nishinomiya, Japan

Kunihiro Yoshida