Abstract: A clutch drum made of a metallic plate having on its peripheral wall portion spline teeth for engaging with clutch plates is formed by pressing with a die which has formed tooth grooves on its periphery and tooth-shaped punches which are disposed around the die so as to move radially back and forth. The force of pressurizing the toothed punches against the tooth flank portions of the spline teeth is made smaller at an open end thereof than at an ordinary portion of the clutch drum such that the thickness of the flank portions of the spline teeth becomes thicker at the open end than at the ordinary portion.

Abstract: A clutch drum has a drum main body made of a metallic plate which is formed into a cup shape by drawing. Spline teeth for engaging with clutch plates are formed by pressing on a periphery of the drum main body. Pulsing teeth for detecting a rotational speed are formed by pressing on the periphery of the drum main body. An apparatus for manufacturing the clutch drum has a forming die onto which the drum main body is externally set in position. The forming die has formed thereon first tooth spaces corresponding to the spline teeth and second tooth spaces corresponding to the pulsing teeth. First tooth-shaped punches are provided so as to be movable radially back forth to form by pressing the spline teeth by urging the periphery of the drum main body into the first tooth spaces.

Abstract: A clutch drum has a drum main body made of a metallic plate which is formed into a cup shape by drawing. Spline teeth for engaging with clutch plates are formed by pressing on a periphery of the drum main body. Pulsing teeth for detecting a rotational speed are formed by pressing on the periphery of the drum main body. An apparatus for manufacturing the clutch drum has a forming die onto which the drum main body is externally set in position. The forming die has formed thereon first tooth spaces corresponding to the spline teeth and second tooth spaces corresponding to the pulsing teeth. First tooth-shaped punches are provided so as to be movable radially back forth to form by pressing the spline teeth by urging the periphery of the drum main body into the first tooth spaces.

Abstract: A process for producing a urethane die. A heat-resistant epoxy adhesive is applied to the inner surface of a recess provided in the body of a die. A urethane primer is applied to the adhesive while the adhesive is still in a semi-hardened state. A punch is inserted into the recess to form a space between the recess and the punch and a urethane resin is injected into the space to form a resin layer on the recess having a shape corresponding to the outer surface of the punch. A reinforcing fibrous material may be incorporated into the resin layer by applying a urethane resin having a lubricant incorporated therein to the surface of the punch and adhering a fibrous material impregnated with the urethane resin to the coated surface of the punch prior to inserting the punch into the recess.

Abstract: A cast-in member and a heating member are set in a mold with the cast-in member being in the vicinity of the heating member. Molten metal is poured through an ignition runner into contact with the heating member to ignite the latter and produce heat. The cast-in member is heated with the heat from the heating member. Thereafter, molten metal is poured through a runner into a cavity in the mold to cast the metal around the cast-in member.