Abstract: Disclosed is a die for compacting a powdered material. The die has a die body having a penetrating die cavity to which a couple of punches are adapted to apply for pressing the powdered material to be supplied to form a compact, and a die holder having a bore into which the die body is shrink fitted. The die cavity is provided with a coating composed of a material which is selected from the group consisting of titanium carbide, titanium nitride, alumina, titanium cyanide, hafnium nitride, chromium nitride, tungsten carbide and DLC, and the die holder is composed of a steel material which is prepared by tempering at a temperature higher than a treatment temperature at which the coating is provided on the die cavity. The die cavity is tapered at a ratio within a range of 1/5,000 to 1/1,000.

Abstract: A cam lobe piece of a built-up type camshaft for an internal combustion engine. The built-up type camshaft includes a hollow shaft fixedly inserted in a shaft opening of the cam lobe piece upon diametrical expansion of the hollow shaft. The cam lobe piece comprises a base circle section having the shaft opening, and a cam lobe section formed integral with the base circle section.

Abstract: A sintered metal sprocket for a silent chain is produced by the following steps. A base mixture is prepared, which contains a powder metallurgical iron powder, a lubricant and a graphite powder. Then, the base mixture is subjected to a compression molding while being heated at above approximately 100° C. thereby to produce a green compact. Then, the green compact is subjected to a sintering at a temperature above approximately 1180° C. For much improving the mechanical performance of the sprocket thus sintered, the same may be subjected to a carbonizing hardening or an induction hardening.

Abstract: Disclosed is a die for compacting a powdered material. The die has a die body having a penetrating die cavity to which a couple of punches are adapted to apply for pressing the powdered material to be supplied to form a compact, and a die holder having a bore into which the die body is shrink fitted. The die cavity is provided with a coating composed of a material which is selected from the group consisting of titanium carbide, titanium nitride, alumina, titanium cyanide, hafnium nitride, chromium nitride, tungsten carbide and DLC, and the die holder is composed of a steel material which is prepared by tempering at a temperature higher than a treatment temperature at which the coating is provided on the die cavity. The die cavity is tapered at a ratio within a range of 1/5,000 to 1/1,000.

Abstract: A sintered metal sprocket for a silent chain is produced by the following steps. A base mixture is prepared, which contains a powder metallurgical iron powder, a lubricant and a graphite powder. Then, the base mixture is subjected to a compression molding while being heated at above approximately 100° C. thereby to produce a green compact. Then, the green compact is subjected to a sintering at a temperature above approximately 1180° C. For much improving the mechanical performance of the sprocket thus sintered, the same may be subjected to a carbonizing hardening or an induction hardening.

Abstract: There is disclosed a method for forming compacts having a hole extending along a direction crossing the compressing direction. In the method, a powder or a pre-compressed compact and a core for forming a hole are assembled in a cavity. The core and a die are set in a condition that the core can move in the compressing direction. The punch compresses the powder and forms a compact. The core does not engage with the die, whereby the core is not exerted with load. Therefore, the method does not need control of compressing for avoiding exertion of load on the core, and can prevent transformation or break of the core. The compact in which the core is inserted is drawn out from the die, so that damages such as break or crumble of the compact is prevented in drawing out.

Abstract: A method of producing a shaft having plate-like member joined thereto comprises the steps of forming a through hole in the plate-like member, forming an annular groove in the inner surface of the through hole of the member, making the surface of the annular groove rugged by knurling, forming an annular projection on a shaft the outer diameter of the annular projection being substantially equal to or slightly smaller than the inner diameter of the through hole of the plate-like member inserting the shaft into the through hole of the plate-like member so that the annular groove is positioned between both sides of the annular projection supporting the side of the plate-like member and an end portion of the shaft and pressing substantially the whole of the side face of the annular projection of the shaft so that a part of the annular projection of the shaft plastically deforms and flows into the annular groove of the plate-like member, whereby the plate-like member is rigidly joined to the shaft.