Nippon Steel Corporation

Nippon Steel Sumitomo Metal Corporation

Kunihiro Yabuno

Kenji Tamura

Koichiro Ishihara

Ken Yoshino

Hiroyuki Kurokawa

Junichi Okubo

Tomohisa Yamashita

Sho Takamoto

Kenji Imanishi

Sam Soo Hwang

Hiroshi Nogami

Kunihiro Yoshida

Yukihiko Kimura

Toru Horiuchi

Keigo Minatani

A support beam includes a first supporting portion, a second supporting portion, and an arm connecting the first supporting portion to the second supporting portion. The arm includes a web and a flange. The flange includes a first end, a second end, and a center portion. The center portion of the flange is connected to an end of the web. The flange includes bent portions at which the center line of the thickness of the flange is bent outward in the extending direction of the web in the region between the first end and the second end in a transverse cross section of the arm.

Support beam

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.

A crankshaft includes a plurality of journals, a plurality of pins, and a plurality of crank arms. The journals are coaxially disposed with the rotational center of the crankshaft. The pins are decentered with respect to the journals. Each of the crank arms is disposed between one journal and one pin to join the one journal with the one pin. One or more of the crank arms integrally include a counterweight. The counterweight includes two side surfaces. An added layer of a material different from that of a crankshaft body is provided on each of side surfaces of the counterweight. When the Young's modulus of the added layer is E and the Young's modulus of the material of the crankshaft body is E0, E/E0 is 0.2 to 0.4.

Crankshaft

A forged crankshaft manufacturing apparatus processes a forged blank with no flash. The forged blank includes at least one rough crank arm having an excess portion protruding from an outer periphery of a side portion thereof. The manufacturing apparatus includes a first die and a second die paired with each other, a retaining device, and a moving device. The first die and the second die bend or crash the excess portion. The retaining device retains at least one of the rough journals or at least one of the rough pins such that a rough pin decentering direction is perpendicular to a reducing direction in which the first die and the second die apply force for reduction. The moving device supports the retaining device such that the retaining device is movable in the reducing direction.

Apparatus and method for manufacturing forged crankshaft

An apparatus for manufacturing a forged crankshaft includes a pair of upper and lower dies and a first tool. The pair of dies deforms first excess portions and thereby thickens both side portions of a rough crank arm, in a region near a rough pin adjacent thereto. The first tool is fitted in an open space made in the pair of dies, and is capable of coming into contact with a rough-journal-facing surface of the rough crank arm, except the side portions in the region near the adjacent rough pin. The first pair of dies and the first tool have first guides to guide the first tool from a retracting position to a contacting position. The first guides include a first guide disposed on at least one of an upper surface and a lower surface of the first tool.

Apparatus for manufacturing forged crankshaft

A method for producing a forged crankshaft includes a die forging step of forming a forged blank having a crankshaft shape by die forging, and a pressing step of pressing the forged blank by a first dies. The forged blank includes first excess portions attached to some or all of crank arms each incorporating a counterweight, each of the first excess portions protrudes from a side portion of the crank arm, in a region near a journal. In the pressing step, the first excess portions are deformed by the first dies such that each of the first excess portions bulges toward a pin. This facilitates the production of a forged crankshaft with a reduced weight and assured stiffness.

Method for producing forged crankshaft

The disclosed production method includes a die forging step of obtaining a forged blank with flash having a crankshaft shape, and a trimming step of removing the flash from the forged blank while nipping the forged blank with a pair of holding dies. In the forged blank, at least one of the rough crank arms have, in a region near an adjacent rough pin, a first excess portion protruding from an outer periphery of a side portion of the rough crank arm. When the forged blank is nipped with the pair of holding dies, the first excess portion is deformed by the pair of holding dies to bulge toward an adjacent rough journal.

The disclosed production method includes a rough forging step of performing die forging to obtain a rough forged blank with flash having a crankshaft shape, and a finish forging step of applying die forging by use of a first pair of dies to the rough forged blank to obtain a finish forged blank with flash. In the rough forged blank, at least one of the rough crank arms have, in a region near an adjacent rough pin, a first excess portion protruding from an outer periphery of a side portion of the rough crank arm. During the die forging in the finish forging step, the first excess portion is deformed by the first pair of dies to bulge toward an adjacent rough journal.

A load due to combustion pressure is applied to each of the crank pins via a connecting rod in a direction from the axis of a piston pin to the axis of the crank pin. Each of the crank arms includes a recess in a surface adjacent to the journal, in a region inward of a peripheral region along the edge of the surface. The recess extends along the peripheral region, and is asymmetric with respect to a crank arm centerline connecting the axis of each of the crank pins to the axis of each of the journals. Each of the crank arms has a maximum flexural rigidity at a point of time when the load onto each of the crank pins due to the combustion pressure reaches a maximum. The crankshaft has a reduced weight and an increased torsional rigidity in combination with an increased flexural rigidity.

Crankshaft for reciprocating engine

A method for producing a forged crankshaft includes: a preforming step of forming a preformed blank with no flash, the preformed blank including a shape of the crankshaft, wherein the crank arm have excess projecting portions at an outer peripheries of side portions of the crank arm near the crank pin; a die forging step of forming a forged blank with flash by pressing the preformed blank with a pair of first dies; and a trimming step of removing the flash from the forged blank. In the die forging step, while a second die is abutted against a journal-side surface of the crank arm and holds the surface, the excess projecting portions of the crank arm are deformed by the first dies so as to increase the side portions of the crank arm in thickness.

Method for producing a forged crankshaft

A crankshaft includes journals that define a central axis of rotation; crank pins that are eccentric with respect to the journals; crank arms connecting the journals to the crank pins; and counterweights integrated with the crank arms. Each of the crank arms has recesses in a surface adjacent to the crank pin. The recesses are disposed inward of peripheral regions in both sides along an edge of the surface, and are disposed along the peripheral regions. The crankshaft has a reduced weight, an increased torsional rigidity and an increased flexural rigidity.

A crankshaft includes journals serving as a central axis of rotation, crank pins decentered from the journals, and crank arms connecting the journals and the crank pins. Some or all of the crank arms have counterweights integrated therewith. At least one of the crank arms has a recess in a crank pin facing surface. The crank arm includes ribs formed respectively in two side portions of the recess along a periphery of the crank arm.

A method for producing a forged crankshaft includes a die forging step, a trimming step, and an excess projecting portion bending step. The die forging step forms a finish forged blank with flash, the finish forged blank including a shape of the crankshaft, in which crank arms have excess projecting portions at outer peripheries of side portions thereof near a crank pin, the excess projecting portions projecting from the outer peripheries. The trimming step removes the flash from the finish forged blank formed in the die forging step. The excess projecting portion bending step bends the excess projecting portions of the crank arms toward a journal-side surface of the crank arm by pressing the crankshaft using a pair of first dies, the crankshaft being obtained by removing the flash in the trimming step.

A method for producing a forged crankshaft includes a die forging step, a trimming step, and an excess projecting portion crushing step. The die forging step forms a finish forged blank with flash, the finish forged blank including a shape of the crankshaft, in which crank arms have excess projecting portions at outer peripheries of side portions thereof near a crank pin, the excess projecting portions projecting from the outer peripheries. The trimming step removes the flash from the finish forged blank formed in the die forging step. The excess projecting portion crushing step crushes the excess projecting portions of the crank arms by pressing the crankshaft using a pair of first dies, the crankshaft being obtained by removing the flash in the trimming step.

Growing community of inventors

Matsubara, Japan

Kunihiro Yabuno