Abstract: The present invention relates to a method of partititioning the internal space of a thin-walled cylindrical member by securing a thin-walled partition member in place within the cylindrical member by means of calking.

Abstract: The present invention relates to a hydraulic valve lash adjuster with which a cam engages directly and in which an oil-introducing chamber can be easily cleaned by a fluid or gas jet stream. In the valve lash adjuster in accordance with the present invention, the cylinder sleeve is formed through its lateral wall with a plurality of openings, and an annular oil-introducing chamber defined between the body and cylinder sleeve is communicated through the openings with the reservoir and consequently with the high pressure chamber. With the above construction of the invention, an extraneous substance such as chips and particles can be removed from the oil-introducing chamber along a fluid jet stream. Thus, since the oil-introducing chamber can be easily and perfectly cleaned by a jet stream during the manufacturing process and moreover during any overhaul work thereafter, reliability and maintainability of the product is markedly improved.

Abstract: The present invention relates to a hydraulic valve lash adjuster which is capable of storing a large quantity of oil therein and exhibits high resistance to wear. In the valve lash adjuster in accordance with the invention, the plunger comprises an upper plunger portion and a lower plunger portion, and the upper and lower plunger portions are welded together with the partition member so that the partition member is sealingly fixed within the plunger. Accordingly, the upper and lower plunger portions are welded together, and simultaneously the partition member is sealingly fixed within the plunger. The plunger thus formed is surface hardened by quenching or carburizing. With the above construction of the invention, therefore, the hardness of the outer surface of the plunger is not impaired and the residual stresses generated by welding do not degrade the resistance to wear and fatigue.

Abstract: A wear-resistant titanium or titanium-alloy member adapted for use as a poppet valve, rocker arm, etc., of an internal combustion engine, which requires lightness in weight and good wear resistance, and a method for manufacturing the member. The surface of the titanium or titanium-alloy member is given a Vickers hardness number of 390 to 1,200, preferably 400 to 800, and a hardened layer depth of 0.1 to 2.0 mm, preferably 0.3 to 1.5 mm, by being melt-hardened while being supplied with hardening elements.

Abstract: The present invention relates to a hydraulic valve lash adjuster which is capable of storing a large quantity of oil therein and exhibits high resistance to wear. In the valve lash adjuster in accordance with the invention, the plunger comprises an upper plunger portion and a lower plunger portion, at least a portion of a partition member extends over the joint between the upper and lower plunger portions, and the upper plunger portion being welded to the lower plunger portion by projection welding so that the partition member is deformed inward by bulging of the welded portion to fix the partition member within the plunger. Accordingly, the upper and lower plunger portions are welded together by projection welding, and simultaneously the partition member is sealingly fixed within the plunger. The plunger thus formed is surface hardened by quenching or carburizing.