[Objects] In a cold-press molding, a taper shape steel rod-like protruding material with a taper shape, the cold press molding apparatus can reduce burrs generated in between back-side tool without high grade lubrication films especially and can extend the life of the molding tool.

[Means for Solving Problems] A cold press molding method of the present invention to make a taper shape steel rod-like protruding material is characterized by holding the processed material preshaped processed material 31a on a backside tool 32, while press-contacting the processed material the free rotation roll 41 freely rotating toward the tip element on the processed material 31a and shaping a taper shape by plastic-reshaping of the processed material.

The present invention provides a method of producing a fuel distribution pipe 10 to be attached to a cylinder head. The method includes providing a forged bar made of metal, forming a main bore 14 in the forged bar so as to extend along an axial direction of the forged bar, forming an injector bore 25 having an injector opening in the forged bar, forming a bolt through hole 22 having a bolt opening in the forged bar, obtaining a base pipe having the main bore 14, the injector bore 25, and the bolt through hole 22 from the forged bar, and bending the base pipe such that the injector opening of the injector bore 25 and the bolt opening of the bolt through hole 22 are provided along a line parallel to the axis of the main bore. The injector bore 25 directly communicates with the main bore 14 and the bolt through hole 22 does not communicates with the main bore 14.

There is provided a method enabling the formation of a ball recirculation groove and a ball rolling groove at the inner circumferential surface of a nut for ball screw use in a state free of deviation in an axial direction, circumferential direction, and radial direction of the nut. An end face (111a) of a flange (111) is formed with a concave part (102), then a blank (101) is attached to a chuck (130) and an inner circumferential surface (101a) of the same and an end face (111a) and outer circumferential surface (111b) of the flange (111) are continuously ground. Due to this, the coaxiality of the inner circumferential surface (101a) of the blank (101) and the outer circumferential surface (111b) of the flange (111) and the perpendicularity of the end face (111a) of the flange (111) to the inner circumferential surface (101a) of the blank (101) are made smaller. This blank (101) is plastically worked at its inner circumferential surface (101a) to form the ball recirculation groove and is cut to form the ball rolling groove while using the concave part (102) as a phase reference, the end face (111a) as an axial direction reference, and the outer circumferential surface (111b) as a radial direction reference.

Provided is a lubricating oil composition for die forging which has excellent lubricity. Also provided is a die forging device which is suitable also for the lubricating oil composition for die forging. The lubricating oil composition for die forging comprises at least two solid lubricants differing in particle diameter, an extreme-pressure additive, and a base oil as the remainder. The die forging device comprises: a pair of dies, an upper die and a lower die, that is for sandwiching therebetween a material to be forged and forming the material; and a lubricating-oil-composition sprayer for spraying the lubricating oil composition for die forging over the surfaces of the dies. The lubricating-oil-composition sprayer is equipped with an oil supply tank in which the lubricating oil composition for die forging is stored and a supply pipe for sucking up the lubricating oil composition for die forging from the oil supply tank and supplying the composition to a nozzle, the supply pipe having a plurality of suction ports.

To produce a rotor material efficiently.

The present invention is directed to a die assembly having a lower die 10 and an upper die 30 for applying forming loads and configured to forge a cylindrical columnar rotor material having a center hole 3 and a vane groove 4. The lower die 10 has a vane groove forming vane portion 13 protruded in a forming hole, and a center hole forming center pin 16 to be arranged in a center of the forming hole. The upper die 30 has an upper die body 31 for applying a main load to portions other than the center pin 16 and the vane portion 13 of the lower die 10, a back-pressure pin 40 fitted in a center pin corresponding hole 35 formed in the upper die body 31 in an advanceable and retractable manner, the back-pressure pin being configured to apply a first sub-load to the center pin 16, and a back-pressure plate 41 fitted in a vane portion corresponding hole 36 formed in the upper die body 31 in an advanceable and retractable manner, the back-pressure plate being configured to apply a second sub-load to the vane portion 13. A tip end face of the vane portion is arranged so as to coincide with or distance from an opening face of the vane portion corresponding hole 36 at the time of die matching.

A high-pressure piping part includes a body structure (10) forged in a closed space (24). The body structure (10) is formed to include a main body portion (11) formed by forward extrusion and side arm portions (12, 212, 312) formed by side extrusion. The main body portion (11) has therein a fiber flow (111) formed along a passage, and the side arm portion has therein a fiber flow (121) formed along the passage. Therefore, the direction in which stress is applied to the passage of the body structure by an internal pressure is approximately perpendicular to the directions of the fiber flows, thereby improving the degree of allowance of the resistance to pressure of the body structure for an injector.