Abstract: Methods for manufacturing a press formed article (22) may include half die cutting a substantially flat material (1, 10) by press forming, thereby forming a first processed material (10′) having a first intermediate press formed article (16) defined therein. The half die cutting step is preferably performed while simultaneously compressing the central portion of the material in order to induce outward plastic flow within the first intermediate press formed article. These methods optionally may include pressing the first intermediate press formed article back into the first processed material, thereby forming a second processed material (10″) having a second intermediate press formed article (20), and separating the second intermediate press formed article from the second processed material, thereby forming a final processed material (10′″) and an unfinished press formed article (22′).

Abstract: In a pipe rack forming method, in a state of holding a pipe forming body by a holding portion in a holding metal mold, at a time of pressing a flat surface portion of the pipe forming body by tooth bottom forming surfaces of respective stages of tooth profile portions in a tooth profile metal mold, the structure is made such as to sequentially employ the tooth profile portions in which a tooth bottom height applied to the flat surface portion is reduced in sequence for the tooth profile portions in the tooth profile metal mold, repeatedly pressing and moving forward and backward mandrels having the same size to an inner periphery of the pipe forming body every time when the respective stages of tooth profile portions in the tooth profile metal mold press the flat surface portion, and forming a rack tooth having a final tooth profile.

Abstract: The invention is intended to reduce the installation cost and running cost, minimize the production cost and increase the tooth surface strength of hypoid teeth.

Abstract: A method for producing a blank for a gear rack for rack-and-pinion steering of motor vehicles includes the following steps: In a first step, a starting material having an essentially circular cross-section is placed into a stamping apparatus containing at least three form tools movable relatively to one another. In a second step, at least one force in at least one direction is exerted upon at least one of the form tools, the form tools moving relative to one another by this force, so that the starting material is reformed into a blank for the gear rack. At least in the axial region of the tooth system of the gear rack to be formed, the blank is provided with a shape differing from a circular cylinder. Using this method, part of the material of the starting material is displaced on one side from the middle into the region of the tooth system to be formed, without having much strain-hardening occur in this region. This makes subsequent production processes easier.

Abstract: A method for producing a rack bar for a steering mechanism in an automobile. A blank pipe is held in a die, which has, at its inner surface, linear tooted portions. Mandrels are inserted repeatedly to the blank pipe while the direction of the insertion is alternately changed, while the insertion of the mandrel on one side of the blank pipe and the withdrawal of the mandrel on the other side are overlapped. Furthermore, lubrication is controlled so that an increased temperature of the work around 200° C. as generated under the plastic deformation of the metal is kept. An increased efficiency as well as reduced cost are obtained.

Abstract: There is provided a method for manufacturing an external gear with a maintained high quality at low cost, which maintains a lubricated state of tooth flanks of the external gear with smaller manufacturing steps than the conventional method. The method for manufacturing an external gear internally in mesh with an internal gear inside the internal gear includes: a cold forging step of setting a material 80 in a lower cold forging die 100 having a tooth profile forming part 102 on an inner periphery of a circular recess 101 thereof, and pressing the material 80 so as to extend outward in the radial direction in order to form the material into a disc 81 and simultaneously, form an external tooth profile on the outer periphery of the disc 81; and a punching step of punching the disc 81 to form holes 11, 15, 17 required for constituting a power transmission mechanism. The surface roughness of the tooth flanks due to the cold forging is maintained on the completed product.

Abstract: For the purpose of providing a speed-changing gear manufacturing apparatus capable of forming back-tapered spline teeth having a chamfer at the tip with high accuracy, by forming both side faces of spline teeth in back-tapered shape and forming the tip in chamfered shape at a time, the present invention is a speed-changing gear manufacturing apparatus comprising dies formed at regular intervals on a circumference, to enable to move a plural number of spline teeth forming units for forming back-tapered spline teeth on lines extending radially from the center axis of the gear material, and a pressing member for moving the spline teeth forming units toward the center axis of the gear material, by pressing the outer circumferential face of the spline teeth forming units of the dies, wherein said spline teeth forming units are constructed in a way to form an open space in which to form both side faces of spline teeth in back-tapered shape and form the tip in chamfered shape at a time, in contact with the adjacent

Abstract: Method for manufacturing speaker bottom yoke, including steps of: 1. calculating product weight according to required dimension; 2. cutting off a blank material with the calculated weight from steel bar (material bar), which blank material can be further planed; 3. performing first time forging to forge one end of the blank material into a stem section with reduced diameter, which stem section can be formed with a sink in accordance with the required shape of the bottom yoke; 4. performing second time forging to forge the other end of the blank material into a bottom disc with larger diameter; and 5. performing third time forging to further forge the bottom disc of the blank material into a predetermined dimension. In the above forging procedure, the diameter of the blank material is forged from large dimension into small dimension and the bottom disc is forged at two times into a specific dimension.

Abstract: In a method of manufacturing a hollow rack shaft, an approximately rectangular plate having a wide rack tooth portion, is bent lengthwise into a gutter-like cross section to provide: at the central portion, a flat bottom portion on which rack teeth are formed later and a pair of mutually facing leg portions, and, in the vicinity of both ends, a semicircular bottom portion and a pair of mutually facing leg portions. The mutually facing leg portions at the central portion have a larger clearance than the clearance of the mutually facing leg portions in the vicinity of both ends. The rack teeth are then formed on the flat bottom portion through the plastic flow of the flat bottom portion and a part of material of the pair of leg portions of this flat bottom portion. The gutter-shaped plate, on which the rack teeth have been formed, is then formed into a tube having a hollow inner surface, by bending the plate and butt joining the edge portions.

Abstract: A method of forming a ratchet wheel adapted to be disposed in at least one end of the ratchet wrench for engaging an element to be turned, includes the step of providing a wheel blank having a generally hollow, cylindrical body formed with a radially projecting rib located midway between an upper hub portion and a lower hub portion, the upper hub portion being integrally formed with an upstanding lip having a diameter equal to or slightly smaller than the diameter of the upper hub portion. The method also includes the step of bending the lip inwardly to form a retention ring adapted to engage the upper surface of the element to be turned and prevent the element from slipping through the wheel of the ratchet wrench.

Abstract: Speed gear are manufactured by integrally molding, by either hot or warm forging, a speed gear section and a clutch spline section. Teeth of the speed gear in the speed gear section and an involute spline parallel to an axial line of the gear in the clutch spline section are rough formed. The involute spline parallel to the axial line of gear formed on the section of clutch spline is formed, by cold forging, into an involute spline with a back taper having a chamfer at the tip. The teeth of the speed gear formed at the speed gear section are finish formed by forming the speed gear teeth by rolling dies, by cold forging, while turning them around a shaft hole with reference to the clutch spline section forming the involute spline with back taper. A speed gear having a speed gear section and a clutch spline section including speed gear teeth and an involute spline with a back taper having a chamfer at the tip is thereby provided.

Abstract: A steel for a gear which is formed on a drive plate gear includes; C: 0.32 to 0.38%, Si: 0.1% or less, Mn: 0.60 to 0.90%, P: 0.03% or less, and S: 0.035% or less.

Abstract: A manufacturing method of a hollow rack bar wherein the load imposed on the rack teeth configuration of a forming die is reduced and precision level of the formation of rack teeth is improved. After the formation of a flat portion, a steel pipe is placed in the forming die having a rack-teeth configuration and a plurality of mandrels having extruding portions of different sizes are sequentially inserted into the steel pipe in order to form rack teeth. A mandrel having a planar extruding portion is firstly inserted and then a mandrel having an extruding portion with an approximately central depression in the longitudinal direction is inserted. The width of the mandrels is smaller than the inside diameter of the steel pipe.

Abstract: A hollow rack shaft is manufactured through a first step, a second step and a third step. At the first step, the plate-like workpiece of substantial rectangular shape is press formed into a gutter-like shape. The first die set used at this step is provided with slant die surfaces for canceling elastic recovering generated at the workpiece when the workpiece is removed from the first die set. At the second step, a row of rack teeth is press-formed on the flat bottom portion of the workpiece formed in the first step. The die set used at the second step is provided with a recess for releasing surplus workpiece material within the die clearance at a stroke end of the pressworking. At the third step, each of a pair of legs of the workpiece is bent in a semi-circular shape so as to be butted to each other. At this time, a mandrel is inserted between the legs of the workpiece.

Abstract: A method for manufacturing a metal part and a sheet pressing wheel, in which reduction of their manufacturing cost is intended by enabling them to be formed only by plastic work such as press-work even if they are very small; and a printer in which such wheels are incorporated as a sheet feed mechanism. In the method for manufacturing a metal part, plastic work is given to a metal plate to thereby manufacture the metal part. The method for manufacturing a metal part comprises a first forming step for performing a punching work for roughly forming at least a part of the outline shape of the metal part; a second forming step for giving a face-pressing work to at least an outline edge portion of the metal part to thereby thin the outline edge portion; and a third forming step for shaping the outline shape again by a punching work.

Abstract: Crown twist forming teeth (14) are formed on the inside circumferential surface of a finishing die (13) with the thickness of each teeth being thinner in the middle part than toward both ends in the axial direction. The finishing die (13) is fitted for axial sliding in the axial direction in the axially central part of a die holder (11) through taper surfaces (12a, 13a) diminishing from its one end to the other. A half-finished work (35, 35′) with its outside circumferential surface having rough-formed twist teeth is brought into screw engagement with the finishing die (13). A first punch (25) for pressing the half-finished work (35, 35′) from one axial end toward the other, and a second punch (26) for pressing the finishing die (13) from one axial end toward the other are provided.

Abstract: A multi-stage forming tool for densifying the outer perimeter of post-sintered powder metal preforms includes a series of axially spaced die plates having different sized die openings arranged from largest to smallest. An oversized powder metal preform it is forced by a punch through the successive die openings causing the outer perimeter material to be displaced and densified. The space between successive dies allows for elastic recovery of the preform to maximize the compressive stress imparted to the preform at each die stage. A high density, high strength powder metal component results which is suitable as a replacement for wrought components in high strength applications such as transmission gears.