Abstract: An expandable tube portion including slots arranged in a staggered fashion is expanded. When the expandable tube portion is expanded, the individual slots open to a cut end portion of the expandable tube portion are transformed to open in V-shape while the whole body of the expandable tube portion is transformed to a lattice configuration. Hence, the tube expansion only need to apply a working force required to bend intersections of the lattice configuration, resulting in the reduction of the working force for tube expansion. As a result, the working force for tube expansion does not open a butt connection portion of a subject matter, negating the need for previously weld bonding the butt connection portion of the subject matter.

Abstract: A connecting structure has a first member and a second member. The first member has a first base portion, a protruding portion that protrudes from an end surface of the first base portion, and a protrusion that extends in a protruding direction of the protruding portion from an end surface of the protruding portion. The second member has a second base portion, and a groove portion formed in the second end surface of the second base portion. The protruding portion fits into the groove portion. The first member and the second member are connected together by a side surface of the protruding portion contacting a side surface of the groove portion. A length from the end surface of the first base portion to a tip end of the protrusion is longer than a length from the end surface of the second base portion to a bottom of the groove portion.

Abstract: A method of press-forming a tubular part having a cross section of an irregular shape crushes a steel tube between an upper die and a lower die in order to form a V-shaped cross section. When the curvature radius of a tip of the upper die is defined as R1, the curvature radius of a bottom portion of the lower die corresponding to the tip of the upper die is defined as R2, and the wall thickness of the steel tube is defined as t; R1, R2, and t satisfy R1+2t=R2 and 1.5t?R1?3t.

Abstract: An expandable tube portion including slots arranged in a staggered fashion is expanded. When the expandable tube portion is expanded, the individual slots open to a cut end portion of the expandable tube portion are transformed to open in V-shape while the whole body of the expandable tube portion is transformed to a lattice configuration. Hence, the tube expansion only need to apply a working force required to bend intersections of the lattice configuration, resulting in the reduction of the working force for tube expansion. As a result, the working force for tube expansion does not open a butt connection portion of a subject matter, negating the need for previously weld bonding the butt connection portion of the subject matter.

Abstract: The forming recesses of a lower die and an upper die are formed to have a semi-oval profile so as to provide a forming space almost oval in section with the dies closed. The parting line between the lower die and the upper die is deviated as much as h from the major axis of the forming space toward the upper die side, and the opening width of the forming recess of the lower die is set to be slightly larger than the opening width of the forming recess of the upper die. A metal bent tube is plastic-deformed into an almost oval shape in section by closing the dies while being compressed in a peripheral direction by the lower and upper dies to eliminate spring-back caused by bending, whereby the buckling and pinching toward the outer side of the tube wall is prevented by the expanded portion of the lower die and buckling toward the inner side of the tube wall is prevented by a step difference formed by the difference in opening width between the lower die and the upper die.

Abstract: A torsion beam type suspension including a torsion beam in which arms are formed by bending both ends of a pipe material and also includes wheel installation members fixed to the arms, respectively. Portions to be inserted of the wheel installation members are inserted into open ends of the arms, and the wheel installation members are welded to the arms. The torsion beam type suspension can be produced at low cost and have high quality.

Abstract: A method of press-forming a tubular part having a cross section of an irregular shape crushes a steel tube between an upper die and a lower die in order to form a V-shaped cross section. When the curvature radius of a tip of the upper die is defined as R1, the curvature radius of a bottom portion of the lower die corresponding to the tip of the upper die is defined as R2, and the wall thickness of the steel tube is defined as t; R1, R2, and t satisfy R1+2t=R2 and 1.5t?R1?3t.

Abstract: A torsion beam type suspension including a torsion beam in which arms are formed by bending both ends of a pipe material and also includes wheel installation members fixed to the arms, respectively. Portions to be inserted of the wheel installation members are inserted into open ends of the arms, and the wheel installation members are welded to the arms. The torsion beam type suspension can be produced at low cost and have high quality.

Abstract: The forming recesses of a lower die and an upper die are formed to have a semi-oval profile so as to provide a forming space almost oval in section with the dies closed. The parting line between the lower die and the upper die is deviated as much as h from the major axis of the forming space toward the upper die side, and the opening width of the forming recess of the lower die is set to be slightly larger than the opening width of the forming recess of the upper die. A metal bent tube is plastic-deformed into an almost oval shape in section by closing the dies while being compressed in a peripheral direction by the lower and upper dies to eliminate spring-back caused by bending, whereby the buckling and pinching toward the outer side of the tube wall is prevented by the expanded portion of the lower die and buckling toward the inner side of the tube wall is prevented by a step difference formed by the difference in opening width between the lower die and the upper die.

Abstract: The present invention intends to provide the partially reinforcing method and apparatus for reinforcing the required part of the metal material having good forming property and relatively low strength (hardness and yield stress) by the press processing. The partial reinforcing method is comprised of a first step and a second step. The first press step generates a plastic strain by a plastic flow of metal material on a front surface and a rear surface of the part to be reinforced, to form a front convex-concave surface and a rear convex-concave surface. The second press step further generates the plastic strain by the plastic flow on the front convex-concave surface and the rear convex-concave surface, to form a front plane surface and a rear plane surface.

Abstract: A mold clamping apparatus includes a frame including a holding portion for holding a mold and an open portion allowing the mold to be inserted into/taken out from the holding portion in a direction of the longer side of the mold, a mold moving device for moving the mold to insert/take out the mold into/from the holding portion through the open portion in the frame, and a mold opening/closing device for opening/closing the mold located outside the frame. This mold clamping apparatus is capable of holding the mold securely in a closed state resisting a pressure acting to open the mold and allows reduction of energy consumption, equipment maintenance cost, production cost, and the size thereof.

Abstract: The present invention intends to provide the partially reinforcing method and apparatus for reinforcing the required part of the metal material having good forming property and relatively low strength (hardness and yield stress) by the press processing.

Abstract: A mold clamping apparatus comprises a frame including a holding portion for holding the mold resisting the generated mold opening force and an open portion allowing the mold to be inserted into/taken out from the holding portion in the direction of the longer side of the mold, mold moving device for moving the mold to insert/take out the mold into/from the holding portion through the open portion in the frame; and mold opening/closing device for opening/closing the mold located outside the frame. This mold clamping apparatus is capable of holding the mold securely in a closed state resisting a pressure intending to open the mold and allows reduction of energy consumption, equipment maintenance cost, production cost, and the size thereof to be achieved.

Abstract: A process for manufacturing a monolithic catalyst converter includes the steps of fitting a monolithic catalyst into a tube-shaped workpiece having opposite opening ends through one of the opposite opening ends, and drawing the tube-shaped workpiece at the opposite opening ends into a funnel shape by means of spinning. Thus, a monolithic catalyst converter is completed without carrying out welding. Hence, the monolithic catalyst converter can be manufactured with a high material yield (or a low scrap rate), at a reduced cost and under a good working environment, because it can be manufactured without the conventional troublesome welding operation and/or a leak-test inspection.

Abstract: A method for forming a projection for projection welding includes the steps of: bending a workpiece such that a first end side portion located on one side of the bent portion is perpendicular to a second portion that is located on the opposite side of the bent portion, and pressing the workpiece between a punch and a V-shaped groove of a die. The pressing of the workpiece causes the first portion to the further bent toward the second portion until the inboard surface of the first portion is brought into contact with the second portion. During the pressing step, the outboard surface of the first portion is brought into contact with one surface of the groove while an end surface of the first portion is brought into contact with a second surface of the groove, with the thicknesses of the first portion and the second portion of the workpiece being plastically changed.

Abstract: A method for continuously producing pipes, each having a polygon-shaped closed cross-section taken perpendicularly to the feeding direction of a strip of metal, which are free from brittleness caused by metal fatigue, and have good precision. A feed-bending method of successively feeding a strip of metal (work) W between a main die body, mandrel, punch and correction punches by predetermined feed lengths, and pressing the work W with these members synchroously with feeding is performed. The work W is gradually bent along designed ridgelines L1 through L2 extending in the feeding direction and defining ridgelines L5 through L8 of a product pipe W1, from the ridgelines L1 and L2 close to widthwise ends e1 and e2 to the ridgelines L3 and L4 in the widthwise center thereof in the course between the vicinity of an inlet and the vicinity of a middle of a device, and then, a resulting rough pipe W0 is corrected from the inside and outside thereof in the vicinity of an outlet of the device.