Abstract: A resin gear 12 includes tooth surfaces 13a and 13b formed front and rear with respect to a rotating direction and an addendum 13c formed between these tooth surfaces and also includes a plurality of helical teeth 13 provided with inclination at a predetermined twist angle with respect to an axial direction. On a part of a contact portion on the tooth surface with a tooth surface of the other gear, a relief portion 15 so as not to touch the tooth surface of the other gear is formed. Damage on the tooth surface caused by stress concentration can be prevented as much as possible.

Abstract: Gear-shaped resin sheets Sa are laminated such that tooth portions 2b are aligned in an axial direction, thereby preparing a spur gear-shaped net-shape body 4. Tooth portions of the resin gear formed in a lower die 12 are pressed in a helical tooth-shaped molding space to deform the tooth portions 4a of the net-shape body 4 into a helical tooth tilted relative to the axial direction, and the direction of reinforcement fibers at the tooth portions 2b of the molded resin gear 1 is tilted relative to the axial direction.

Abstract: A resin rotating body 1 is configured by a ring-shaped resin ring 2, and a metallic bush 3 which is fitted to an inner circumferential surface 2a of the resin ring, and projections 3a as rotation preventing means that connects the resin ring and the metallic bush so that the resin ring and the metallic bush do not rotate with respect to each other are provided on an outer circumferential surface of the metallic bush. Projections of the metallic bush are further provided at positions eccentric forward in a press-fitting direction of the metallic bush from a center in the axial direction of the metallic bush.

Abstract: Gear-shaped resin sheets Sa are laminated such that tooth portions 2b are aligned in an axial direction, thereby preparing a spur gear-shaped net-shape body 4. The net-shape body is accommodated in a net-shape body holder 14 having a spur gear-shaped holding space 14a. A spur gear-shaped pushing member 15a provided in an upper die 15 is lowered to heat and compress the net-shape body 4, while tooth portions of the resin gear formed in a lower die 12 are pressed in a helical tooth-shaped molding space to deform the tooth portions 4a of the net-shape body 4 into a helical tooth tilted relative to the axial direction, and the direction of reinforcement fibers at the tooth portions 2b of the molded resin gear 1 is tilted relative to the axial direction. A resin gear that hardly causes peeling off of resin by a load applied to a tooth surface can be obtained, and a production apparatus suitable for producing such resin gear is provided.

Abstract: A resin rotating body 1 is configured by a ring-shaped resin ring 2, and a metallic bush 3 which is fitted to an inner circumferential surface 2a of the resin ring, and projections 3a as rotation preventing means that connects the resin ring and the metallic bush so that the resin ring and the metallic bush do not rotate with respect to each other are provided on an outer circumferential surface of the metallic bush. The resin ring is molded by heating and compressing an element body in which a plurality of sheet-shaped resins manufactured by sheet making are stacked in layers in an axial direction and a diameter of the inner circumferential surface is formed to be substantially the same diameter as the outer circumferential surface of the metallic bush, and the metallic bush is integrally connected to the resin ring by being press-fitted to the inner circumferential surface of the element body along the axial direction.

Abstract: A copper alloy for electronic instruments is disclosed which comprises 2.0 to 7.0 wt. % of Sn, 1.0 to 6.0 wt. % in total amount of at least one kind of Ni, Co and Cr, o.1 to 2.0 wt. % of Si, and the remainder of Cu and unavoidable impurities, thereby further the content of O.sub.2 in unavoidable impurities being not more than 50 ppm, the content of S being not more than 20 ppm, and the average particle diameter of precipitates being not larger than 10 .mu.m. As the uses of such copper alloys, lead material for semiconductor elements and connector, socket, spring and terminal for electronic and electric instruments are claimed.

Abstract: A copper alloy is disclosed which comprises 0.01 to 1.0 wt. % of Cr, 0.01 to 8 wt. % of Sn, 0.001 to 5 wt. % of at least one of 0.001 to 5 wt. % of Zn, 0.001 to 0.5 wt. % of Mn and 0.001 to 0.2 wt. % of Mg and the remainder of Cu, the content of O.sub.2 therein being not more than 0.005 wt. %. A method of manufacturing therefor is described wherein, after the hot processing or the heat treatment at 800.degree. to 950.degree. C., the alloy is cooled by passage through a region of 800.degree. to 400.degree. C. within 20 minutes, then following cold processing, heating treatment is carried out for at least 1 minute at 400.degree. to 650.degree. C. The alloy with the composition aforementioned is used as an alloy material for electric or electronic instruments.

Abstract: A copper alloy is disclosed, which contains 0.1 to 3.0 wt % of Ni, 0.1 to 1.0 wt % of Ti, the ratio of Ni to Ti being 4.ltoreq.Ni/Ti thereby, 0.1 to 6.0 wt % of Sn, and 0.005 to 3.0 wt % in total of one or more elements selected from the group consisting of Zn, Mn, Mg, Ca, RE, B, Sb, Te, Si, Co, Fe, Zr, Ag, Mm and Al, and consists of the remainder of Cu and the inevitable impurities. The method for the manufacture of the alloy is characterized in that, after copper alloy ingot was maintained and homogenized for 0.5 to 15 hours at 750.degree. to 960.degree. C. prior to rolling, the hot rolling is carried out starting from a temperature of 700.degree. to 880.degree. C. and the cooling is made immediately after the end of rolling.