Abstract: Two workpieces are frictionally welded by a friction welding apparatus which comprises a fixing holder and a rotary holder. One of the workpieces are held by a fixing chuck provided on the fixing holder, while the other is held by a rotary chuck provided on the rotary holder. Pressing portions are formed on opposing surfaces of the chucks.

Abstract: A valve spring retainer is fixed at the upper end of a poppet valve via a pair of cotters in a valve-operating mechanism of an internal combustion engine. The valve spring retainer comprises a hollow inverted-frustoconical portion and an outward flange at the end thereof. The lower surface of the outward flange retains the upper end of a valve spring on the lower surface. An annular projection is provided on the outward flange to restrict sideward movement of the valve spring and to increase rigidity of the retainer.

Abstract: To operate a poppet valve in an internal combustion engine, a valve operating mechanism comprises a valve spring retainer which has a taper bore, a pair of cotters which is inserted in the bore to support the poppet valve, and a valve spring between the valve spring retainer and a cylinder head. There is provided means for preventing the cotters from falling out the bore.

Abstract: A poppet valve is used in an internal combustion engine of an automobile. A valve body which comprises a valve stem and a valve head is made of high-strength plastic resin. The valve head is covered with a metal head cover, and the end of the valve stem is covered with a cylindrical metal cap, thereby decreasing weight of the poppet valve.

Abstract: To operate a poppet valve in an internal combustion engine, a valve operating mechanism comprises a valve spring retainer which has a taper bore, a pair of cotters which is inserted in the bore to support the poppet valve, and a valve spring between the valve spring retainer and a cylinder head. There is provided means for preventing the cotters from falling out the bore.

Abstract: A tappet is used in an internal combustion engine. A cam-slidably-contacting member is placed on a top wall of a tappet body via diffusing material that includes a mixture of one or more elements of Zn, Mg, Sn, Cu and Pb. The cam-slidably-contacting member and the tappet body are pressed with the diffusing material held therebetween, so that the diffusing material is diffused into the tappet body and the cam-slidably-contacting member until the layer of the diffusing material does not substantially remain, and a tappet of high strength is formed.

Abstract: A tappet made of light metal comprises a ceiled cylindrical tappet body made of light metal, and a cam receiving plate made of hard metal which has the same outer diameter as that of the tappet body, and which is provided at its outer peripheral edge with a sharp annular piece, the cam receiving plate being integrally coupled to the tappet body by causing the annular piece to bite into the top surface and welding the annular piece and the top surface. With this structure, the tappet body and the cam receiving plate made of different materials can be bonded strongly.

Abstract: A tappet made of Al alloy is used in a valve operating mechanism of an internal combustion engine of a vehicle. On the whole outer circumferential surface of the tappet, a helical projection and a helical groove are formed alternately to form an uneven surface. A plurality of uneven surfaces are formed on a ridge of the projection at regular intervals. The outer circumferential surface is coated with a wear resistant Fe film by thermal spraying. The uneven surfaces on the projection provide high adhesion strength of the film to the outer circumferential surface of the tappet to improve peel resistance, thereby increasing durability and reliability of the Al alloy tappet.

Abstract: A tappet is used in an internal combustion engine. A cam-slidably-contacting member is placed on a top wall of a tappet body via diffusing material which comprises mixture of one or more elements of Zn, Mg, Sn, Cu and Pb. The cam-slidably-contacting member and the tappet body are pressed with the diffusing material held therebetween, so that the diffusing material is diffused into the tappet body and the cam-slidably-contacting member until a layer which comprises only the diffusing material does not substantially remain to form the tappet having high strength.

Abstract: An Al alloy tappet used in an internal combustion engine has a spiral groove on the outer circumferential surface of a tappet body. The spiral groove is formed by pushing a cutting tool against the outer circumferential surface and feeding it in an axial direction. Near the lower end of the tappet body, feed rate is decreased, and the cutting tool is moved away from the tappet body to form a smaller spiral groove which increases in diameter downwards. The outer circumferential surface of the tappet body is covered with a coating layer such as Fe, and the lower end which has the smaller spiral groove is chamfered.

Abstract: A tappet made of Al alloy is used in a valve operating mechanism of an internal combustion engine of a vehicle. On the whole outer circumferential surface of the tappet, a helical projection and a helical groove are formed alternately to form an uneven surface. A plurality of uneven surfaces are formed on a ridge of the projection at regular intervals. The outer circumferential surface is coated with a wear resistant Fe film by thermal spraying. The uneven surfaces on the projection provide high adhesion strength of the film to the outer circumferential surface of the tappet to improve peel resistance, thereby increasing durability and reliability of the Al alloy tappet.

Abstract: A method of manufacturing a tappet which is used in an internal combustion engine of vehicles is provided. A core material of the tappet has a helical groove on the outer circumferential surface, and a wear resistant coating layer, the ends of which are chamfered. In the vicinity of the end of the core material the helical groove gradually becomes small toward the end, thereby preventing peaks of the helical groove from exposure to the outside.

Abstract: A tappet is used in an internal combustion engine. A cam receiving plate which contacts a cam is brazed on the upper surface of a top wall of a tappet body. The whole surface of the cam receiving plate can act as a cam follower surface, thereby making the outer diameter of the cam receiving plate to the minimum size corresponding to projected length of a nose of a rotary cam and lightening the tappet.

Abstract: A tappet is used in an internal combustion engine of vehicles. A core material of the tappet has a helical groove on the outer circumferential surface, and a wear resistant coating layer the ends of which are chamfered. In the vicinity of the end of the core material, the helical groove gradually becomes smaller toward the end, thereby preventing peaks of the helical groove from exposure to the outside.

Abstract: After primary blasting is applied to the outer circumferential surface of a cylindrical valve lifter the upper end of which is closed with an abrasive to form a rough surface, a secondary blasting is applied to the rough surface with an abrasive which has particle size smaller than that of the first abrasive. Smaller irregularities are formed on the rough surface, and a coated layer is formed by thermal spraying on the surface, thereby increasing adhesive strength of the coated layer by anchoring effect.