Abstract: A method for producing a camshaft having a tubular steel shaft and a sintered cam piece joined to the shaft. The sintered cam piece has iron tetroxide film at its surface. The camshaft is produced by assembling a powder compact to the steel shaft to provide a camshaft assembly, sintering the assembly to provide an integral assembly, correcting bending to the assembly, annealing the assembly, grinding the cam piece and effecting vaporization treatment to the assembly at a temperature lower than the annealing temperature.

Abstract: A camshaft comprising a steel shaft and a plurality of cam pieces fitted on the shaft. The cam piece is made from a sintering alloy material and bonded to the shaft by sintering. The shaft has pin-receiving holes perpendicular to the axis of the shift. The cam piece is formed on its side surface with a pin-receiving groove. A positioning pin has a lower portion tightly fitted in the hole of the shaft and an upper portion fitted in the groove to position the cam piece with respect to the shaft during sintering.

Abstract: A camshaft having a tubular steel shaft and a sintered cam piece joined to the shaft. The sintered cam piece has iron tetroxide film at its surface. The camshaft is produced by assembling a powder compact to the steel shaft to provide a camshaft assembly, sintering the assembly to provide an integral assembly, correcting bending to the assembly, annealing the assembly, grinding the cam piece and effecting vaporization treatment to the assembly at a temperature lower than the annealing temperature.

Abstract: A camshaft comprising a steel shaft and a plurality of cam pieces fitted on the shaft. The cam piece is made from a sintering alloy material and bonded to the shaft by sintering. The shaft has pin-receiving holes perpendicular to the axis of the shaft. The cam piece is formed on its side surface with a pin-receiving groove. A positioning pin has a lower portion tightly fitted in the hole of the shaft and an upper portion fitted in the groove to position the cam piece with respect to the shaft during sintering.

Abstract: An assembled cam shaft including a steel cam shaft member, a journal member made of sintered material and a cam lobe. The sintered material consisting essentially of 0.5 to 4.0% by weight of carbon, 0.1 to 0.8% by weight of phosphorus, 5 to 50% by weight of copper, 1% by weight or less of manganese, 2% by weight or less of silicon, and the balance being iron and impurities.

Abstract: A camshaft having a steel shaft and cam pieces made from a sintering iron-base alloy material and fixed to the shaft by sintering. Prior to sintering, the green or pre-sintered cam piece is fitted on the shaft and positioned by a steel positioning pin, which is inserted both into a pin-receiving hole in the shaft and into a pin-receiving groove on the side surface of the cam piece. The positioning pin contains carbon less than the steel shaft. This results in that the carbon diffusion initiates at a predetermined position where the pin and the cam piece are in contact with each other and that the cam piece always shrinks about the position.

Abstract: A method of making a camshaft of the type having a cam piece composed of outer and inner layers which comprises the steps of molding a green cam piece in a manner that the outer and inner layers are respectively made from powders of outer-layer and inner-layer forming materials, fitting the green cam piece on a steel shaft to produce a green camshaft assembly, and sintering said green camshaft assembly at a temperature in which the materials shrink and yield a liquid phase to produce a camshaft having a cam piece diffusion-bonded to the outer periphery of the shaft.The outer-layer forming material is prepared to have an axial shrinkage of 4 to 10% and shrink more than said inner-layer forming material prepared to have an axial shrinkage of 2.5 to 6%.

Abstract: An iron-based anti-wear sintered alloy member containing at least 1.5 weight % C, 0.5 to 3.5 weight % P, and one or both of Mo and W in an amount of 0.5 to 3.0 weight % in terms of Mo (the conversion rate of W being 0.5) in addition to iron and having a phosphatic film formed at sliding contact portions. In addition to the above-described elements, one or both of Ni and Cu may be incorporated in an amount of 0.5 to 5.0 weight % in terms of Ni (the conversion rate of Cu being 0.5), of 0.3 to less than 8.0 weight % of Cr may be incorporated, or one or both of Ni and Cu may be incorporated in an amount of 0.3 to 0.7 weight % in terms of Ni together with 0.3 to 0.7 weight % of Cr.

Abstract: A camshaft in which the outer peripheral surface of a shaft (13) is provided with an axial groove (14), and a fitting member (10) is connected to the shaft (13) by liquid-phase sintering under the state in which a projection (12) on the surface of a bore (11) in the fitting member (10) is fitted into the groove (14). The projection (12) in the bore (11) of the fitting member (10) is formed so that its cross-sectional configuration is smaller than that of the groove (14) in the shaft (13). Therefore there is no possibility that the fitting member (10) made of a green compact can be damaged during the fitting or sintering.

Abstract: A composite camshaft is formed by brazing a journal to a shaft. After a brazing material is fitted into an annular groove formed on the center of the inner peripheral surface of a shaft-receiving bore in the journal, the journal is fitted onto the shaft and the brazing material is heated until it melts. The molten brazing material consequently completely fills a clearance between the inner peripheral of the shaft-receiving bore in the journal and the outer peripheral surface of the shaft, ensuring that the journal and the shaft are firmly connected.

Abstract: A tool for supporting a composite camshaft having a steel shaft and a sintered piece to be joined to the steel shaft through sintering in a sintering furnace. The tool comprises a graphite frame having at least two sides, in an upper portion of which a groove means is formed. A ceramic layer is provided on a surface of the groove means. When sintering is performed using such a tool, the tool will not deform even if the tool is exposed to an environment of high temperature, such as the temperature higher than 1,100.degree. C., and therefore, bending of the composite camshaft will not occur during sintering. In addition, the ceramic layer prevents diffusion of carbon from the graphite frame to the steel shaft of the composite camshaft, and therefore, a hardening of the steel shaft due to carbonizing will not occur. As a result, reliability of the joint between the sintered piece and the steel shaft is increased.

Abstract: A composite camshaft having a plurality of ferrous fitting members, such as cam lobes and journals, firmly bonded to a steel shaft by sintering in the presence of a liquid phase. The fitting members are fabricated as a green compact from metal powders and pre-sintered to axially shrink the compact by one-half a preselected allowance of shrinkage. Thereafter the pre-sintered fitting members are fitted on the shaft and sintered to axially shrink the compact by the remaining allowance of shrinkage and metallurgically join the shaft.