Abstract: A heating method, a heating apparatus, and a method of manufacturing a press-molded article using the heating method are provided. A pair of electrodes is arranged on a workpiece along a first direction. Each electrode has a length extending across a first heating area of a workpiece in the first direction. At least one of the electrodes is moved in the first heating area and along a second direction intersecting the first direction at a constant speed while applying electric current between the pair of electrodes to heat the first heating area by direct resistance heating. The electric current applied between the pair of electrodes is adjusted such that a heating temperature is adjusted for each segment into which the first heating area is divided so as to be side by side in the second direction.

Abstract: A rack manufacturing apparatus and a rack manufacturing method are provided. The rack manufacturing apparatus includes a first support portion configured to support a hollow or solid first bar on which first rack teeth are formed, a second support portion configured to support a hollow or solid second bar such that an axial center line of the second bar is aligned with an axial center line of the first bar, a base configured to cause the second support portion to approach the first support portion, and a rotary driving portion configured to rotate the second support portion about the axial center line of the second support portion relative to the first support portion so as to join an end portion of the first bar and an end portion of the second bar by a friction pressure welding.

Abstract: According to an embodiment, an induction heating coil includes a heating conductor portion which is formed of a conductor member and has a zigzag shape in which a bent portion opened to one side in a first direction and a bent portion opened to the other side in the first direction are alternately continuously arranged in opposite directions along a second direction crossing the first direction

Abstract: A rebar structure includes a plurality of column longitudinal bars to be connected to a beam. The yield point or the 0.2% proof stress of at least a portion the column longitudinal bars is larger than the yield point or the 0.2% proof stress of a normal reinforcing bar defined by JIS G 3112.

Abstract: A rebar structure includes a plurality of column longitudinal bars to be connected to a beam. The yield point or the 0.2% proof stress of at least a portion the column longitudinal bars is larger than the yield point or the 0.2% proof stress of a normal reinforcing bar defined by JIS G 3112.

Abstract: According to an embodiment, an induction heating coil includes a heating conductor portion which is formed of a conductor member and has a zigzag shape in which a bent portion opened to one side in a first direction and a bent portion opened to the other side in the first direction are alternately continuously arranged in opposite directions along a second direction crossing the first direction.

Abstract: Provided are: a welded structural member whose spot-welded part has both strength and ductility, and whose rupture strength proven by a rupture test such as a cross tensile test is high; and a method for welding such a structural member. The welded part 3 of the welded structural member 1 made of the above steel plates bonded by overlapping their faces and forming the welded part 3 by spot welding includes: a molten and solidified part 4; and a heat-affected zone 5 surrounding the molten and solidified part 4. The hardness on the welded surface increases to harder than the hardness of the steel plates 2 (base material) along a direction from a region outside the heat-affected zone 5 toward the heat-affected zone 5.

Abstract: A welding structural part 1 is manufactured by overlapping the surfaces of steel sheets 2, and forming a weld zone by spot welding. The weld zone 3 includes: a weld nugget 4; and a heat affected zone 5 surrounding the weld nugget 4, wherein the hardness in the weld zone increases along an exterior region 6 of the heat affected zone 5 toward the heat affected zone 5, and then decreases along the heat affected zone 5 toward the central region of the weld nugget 4. In the boundary region between the weld nugget 4 and the heat affected zone 5, the weld nugget 4 may have a convex portion 4A bulging into the heat affected zone 5 along the overlapped portion. The steel sheets 2 contain carbon in 0.15 mass % or more.

Abstract: A wire inserting device, an elongated workpiece winding apparatus having the wire inserting device, and a wire inserting method are provided to insert a wire in a bundle of an elongated workpiece at an intermediate point in the bundle. The wire inserting device includes a detector arranged at a position corresponding to the intermediate point, and a wire holder configured to releasably hold the wire. The detector is configured to move when pushed by the elongated workpiece placed at the intermediate point during a formation of the bundle of the elongated workpiece. The wire holder is configured to move in synchronization with the detector to insert the wire in the bundle at the intermediate point.

Abstract: To heat a workpiece having a recess portion provided along a longitudinal axis of the workpiece, the workpiece is inserted into an induction heating coil, and the induction heating coil or the workpiece is along an axial direction of the workpiece. The induction heating coil has a conductor configured to surround the workpiece around the axis of the workpiece. The conductor has a protruding portion protruding inwardly to face the recess portion of the workpiece.

Abstract: A rack manufacturing apparatus and a rack manufacturing method are provided. The rack manufacturing apparatus includes a first support portion configured to support a hollow or solid first bar on which first rack teeth are formed, a second support portion configured to support a hollow or solid second bar such that an axial center line of the second bar is aligned with an axial center line of the first bar, a base configured to cause the second support portion to approach the first support portion, and a rotary driving portion configured to rotate the second support portion about the axial center line of the second support portion relative to the first support portion so as to join an end portion of the first bar and an end portion of the second bar by a friction pressure welding.

Abstract: An induction heating coil (3) has a primary coil (4) to which electric power is supplied and a ring-shaped secondary coil (5) forming a closed circuit. The primary coil (4) has a base-side portion that covers an outer periphery of the secondary coil (5) and a distal-side portion extending from the base-side portion in the center axis direction of the secondary coil (5) in a state in which the base-side portion covers the secondary coil (5). The opening width of the base-side portion is greater than the opening width of the distal-side portion. The secondary coil (5) is provided such that it can be inserted into and removed from the inside of the primary coil (4) from the base-side portion of the primary coil (4).

Abstract: A main reinforcing bar has a strength transition portion between a normal strength portion and a high strength portion. The high strength portion is arranged in a joint section. The boundary between the normal strength portion and the strength transition portion is configured as a deigned point. The designed point is designed such that, at the time of an earthquake, the main reinforcing bar yields at the designed point before the main reinforcing bar yields at the root of the beam at of the joint section. The boundary between the high strength portion and the strength transition portion is located in the joint section, and the root of the beam is located at the strength transition portion. The strength of the strength transition portion at the root of the beam is equal to or higher than the required strength.

Abstract: A heat treatment apparatus is configured to perform a heat treatment on a workpiece while rotating the workpiece. The heat treatment apparatus includes a rotary shaft configured to support the workpiece and on which a discharge nozzle is provided to spray cooling liquid toward the workpiece, a fixing base having a supply port and a discharge port for the cooling liquid, a coupling section coupling the fixing base and the rotary shaft to each other in a relatively rotatable manner, and a detector configured to detect a flow of the cooling liquid discharged from the discharge port. A supply passage and a discharge passage are formed inside the fixing base, the rotary shaft and the coupling section. The supply passage extends from the supply port and to the discharge nozzle. The discharge passage branches from the supply passage inside the rotary shaft and leads to the discharge port.

Abstract: A heating method, a heating apparatus, and a hot press holding method for a plate workpiece are provided. The plate workpiece has a first region and a second region. A cross sectional area of the first region in a widthwise direction of the plate workpiece is substantially uniform along a longitudinal direction of the plate workpiece or is monotonically increased or decreased along the longitudinal direction. The second region is adjoining a portion of the first region in a monolithic manner. The method includes heating the second region, and heating at least the first region by direct resistance heating along the longitudinal direction. The second region is heated before heating the first region such that the first region and the second region are heated to be in a given temperature range.

Abstract: A metal core for a resin gear and a resin gear composite member are provided. The metal core includes a boss portion into which a shaft is press-fitted, a ring portion to which an outer peripheral resin is joined, and a connecting portion via which the boss portion and the ring portion are coaxially provided. The boss portion is arranged on one side of the connecting portion at an inner circumference of the connecting portion and extends annularly in an axial direction. The ring portion is arranged on the same side of the connecting portion at an outer circumference of the connecting portion and extends annularly in the axial direction. The boss portion, the connecting portion, and the ring portion are formed of an integrally continuous material. The boss portion is thicker than the connecting portion and the ring portion.

Abstract: A method of manufacturing a metal core for a resin gear is provided. The metal core has a boss portion into which a shaft is press-fitted and a ring portion to which an outer peripheral resin is joined. The method includes swaging a plate material having a center hole by pressing the plate material in an axial direction to form a swaged body, and forging the swaged body by pressing the swaged body in the axial direction under a higher pressure. The swaging includes deforming a portion around the center hole in the axial direction to form an inner circumferential swaged portion, and deforming an outer circumferential portion of the plate material in the same axial direction to form an outer circumferential swaged portion. The forging includes forming the inner circumferential swaged portion into the boss portion, and forming the outer circumferential swaged portion into the ring portion.

Abstract: A rack bar includes a shaft portion, a rack toothed portion provided on the shaft portion, and a dummy toothed portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion, each of the rack teeth including a contact face arranged obliquely relative to the axial direction to contact the pinion gear. The dummy toothed portion includes at least one dummy tooth provided on at least one side of the rack toothed portion in the axial direction such that the dummy tooth is arranged parallel to and next to the rack teeth. The dummy tooth is designed such that a whole height of the dummy tooth is smaller than a whole height of each of the rack teeth.

Abstract: The core metal for resin welding improves bonding strength between an outer peripheral resin member and the core metal. The outer peripheral resin member 30 is welded to the peripheral surface 21 of the core metal 20 by fitting the core metal into a fitting hole 31 of the outer peripheral resin member 30, preparing the outer peripheral resin member 30 providing the fitting hole 31 with a smooth internal wall surface; preparing the core metal 20 wherein streaky protrusions 26 and smooth portions 25 are provided; allowing the top parts of the protrusions 26 to contact, and the smooth portions of the core metal 20 to face the smooth internal wall surface; and induction heating to weld the outer peripheral resin member 30 to the protrusions 26 and the smooth portions 25.

Abstract: A rack bar includes a shaft portion and a rack toothed portion provided on the shaft portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion to mesh with a pinion gear. Each of the rack teeth includes a tooth tip portion, a contact face arranged obliquely relative to the axial direction and configured to contact the pinion gear, and a rounded corner portion between the tooth tip portion and the contact face. A first radius defining a central area of the rounded corner portion with respect to a tooth width direction is larger than a second radius defining another area of the rounded corner portion other than the central area.