Abstract: There is provided a new method of improving properties of the surface of an internal combustion engine valve made from titanium alloy, which comprises; the steps of (a) forming a surface undercoat layer of nickel on a surface of the engine valve; (b) heating the resulting nickel undercoated valve in vacuum or in an atmosphere of inert gas, at the temperature of 450.degree. C. to 600.degree. C., for one to four hours; (c) forming further a three component coat layer comprising nickel, phosphorus and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof, on the surface of the nickel undercoat layer; and (d) heating the resulting coat layer formed on the nickel undercoat layer, at the temperature of 350.degree. C. to 550.degree. C., for one to four hours, so as to make the particles of ceramic material uniformly and homogeneously dispersed in said coat layer.

Abstract: A tappet in a direct acting type valve operating mechanism of an internal combustion engine comprises a top wall and a cylindrical portion. The upper and lower surfaces of the top wall contacts a rotary cam and the end of a stem of an engine valve respectively. A hard metal layer is formed at the upper and lower surfaces of the top wall to increase strength thereof, thereby increasing wear resistance and durability of the tappet.

Abstract: A poppet valve comprises a valve stem and a valve head which is provided at one end of the valve stem. A plurality of arcuate fins are provided on the surface of the valve head. Two semicylindrical cotters are pushed by a press member, so that the valve is driven and reciprocated. When the valve is moved upward or downward to open a port of a valve casing in which the valve is contained, fluid flows, thereby allowing fluid pressure to act on the fins, so that valve rotates little by little around its axis owing to a slight gap between the cotters and the valve stem.

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.

Abstract: There is provided an internal combustion engine valve having a body, a head, and a contact surface disposed on said head adapted to periodically enter into gas-sealing engagement with a valve seat, said contact surface being formed in metal deposit welded to said valve head, the composition of said metal deposit being Al and B free, and measured at said contact surface, consisting essentially ofcarbon: 1.3 to 2.0 weight percent;chromium: 19 to 23 weight percent;molybdenum: 8 to 11 weight percent;nickel: 17 to 21 weight percent;manganese: 6 to 13 weight percent;silicon: less than 0.5 weight percent;oxygen: less than 0.06 weight percent;balancing iron and inevitable impurities.

Abstract: In a pressure fluid control valve device, the fluid exhausted from an internal combustion engine flows through a pair of paths selectively or simultaneously. Each of the paths is opened and closed by a butterfly valve fixed to a valve shaft. A coupling for connecting the valve shafts across the paths comprises a slitting recess and a projection provided at the opposing ends of the valve shafts respectively. The direction of the surface of the recess and the projection is set to within 30 degrees with respect to the direction of the surface of the valve disc fixed to the valve shaft having the recess. Thus, the corner of the recess is not engaged with the bearing surface which is loaded, thereby making axial length for connecting the valve shafts to zero to manufacture the light and compact device.

Abstract: In a tappet for use in an internal combustion engine, a tip is fitted in an engage bore between the top wall of the tappet and an engine valve shaft. The tip has a chamfered portion over which a circumferential projection is pressed by a punch so as to fix the tip in the engage bore firmly. A caulking groove is formed by the punch around the engage bore on the top wall. Owing to the chamfered portion of the tip, a cracking is prevented at the bottom of the groove.

Abstract: To manufacture an Al alloy tappet in an internal combustion engine, an intermediate which has a circular upper wall and a cylindrical skirt is formed in the first forging step. In the second forging step, a recess is formed on the lower surface of the upper wall. Relatively large-sized metallic structure in the first forging step is finally collapsed, thereby increasing strength and rigidity of the upper wall around the recess.

Abstract: There is provided a new structure of an engine valve made from titanium alloy, having three component coat surface layer formed on the surface of the reciprocating shaft thereof, wherein the composition of the three component coat surface layer comprises nickel, phospher and particles of material selected from the group consisting of silicone carbide, silicone nitride, boron nitride, and the combination thereof; said particles are uniformly dispersed in said coat surface layer; and said coat surface layer is formed via a binding layer or directly on the surface of the shaft.

Abstract: A method of manufacturing a tappet used in a valve operating mechanism of a direct acting type in an internal combustion engine. A tip engaged with a center bore of an inner upper surface of a tappet body includes upper and lower convex surfaces and a rounded upper circumferential corner having a certain curvature. thereby preventing concentration of stress even if the tip is subject to high compression load. Thus, durability and reliablity of the tappet are increased.

Abstract: There is provided a structure of a shim to be inserted in a clearance provided between a cam and a tappet in a moving valve mechanism of an internal combustion engine, wherein a volumetric density of the shim body is changed such that it is maximized at an upper surface of the shim, at which the shim is in contact with the cam when a compression load or shock from the cam is applied to the shim, and the density is gradually decreased from the maximized portion to a lower or peripheral portions.

Abstract: A tappet for use in an internal combustion engine comprises Al-alloy base material and a sprayed layer on the outer surface which is slidable with a cylinder head. The sprayed layer is made of Fe-alloy which comprises not more than 0.1% by weight of C, 0.6-2.0% by weight of Mn and the balance of Fe, thereby providing high hardness, high toughness and low cost. The sprayed layer may further contain 0.1-1.0% by weight of Si.

Abstract: A shim attaching/detaching tool for a tappet of an internal combustion engine includes as essential components an air supplying tube, an air blowing tube and a nozzle formed at an opening portion of the air blowing tube at the foremost end of the same. When compressed air is blown from the nozzle toward the shim while the air supplying tube is inclined at an angle of about 45 degrees and the nozzle is oriented toward the fitting portion of the shim fitted into a circular cavity, the shim is thrusted against the opposite side of the cavity and the compressed air is then introduced into the space below the shim through the gap appearing around the fitting portion of the shim, whereby the shim is floated up away from the cavity so as to enable it to be easily exchanged with another shim having a different thickness.

Abstract: A tappet is used in a valve operating mechanism of a direct acting type in an internal combustion engine. A tip engaged with a center bore of an inner upper surface of a tappet body comprises upper and lower convex surfaces and a rounded upper circumferential corner having a certain curvature, thereby preventing concentration of stress even if the tip is subject to high compression load. Thus, durability and reliablity of the tappet are increased.

Abstract: A hydraulic tappet comprises a body which comprises an outer tube, an inner tube and an upper portion which connects the two tubes at the upper end. Within the inner tube, there are provided inner and outer plungers. The outer plunger abuts a valve stem of an engine valve in a DOHC-type engine. The outer plunger is supported by a reinforcement member directly or via the inner plunger to provide high rigidity.