A coupling structure includes a hollow rod section formed of a metal pipe and fastening sections formed by plastic deformation of the metal pipe so as to be connected with end sections of the hollow rod section. The fastening section includes a pair of base end sections which are each connected with a peripheral wall section forming a closed cross-section at the end section of the hollow rod section, and are separated from each other, and a bottom wall including a flat surface connected with the pair of the base end sections, and a pair of front end sections including a pair of side walls curving inwards from at least widthwise end sections of the bottom wall on a base end section side.

A coupling structure includes a hollow rod section formed of a metal pipe and fastening sections formed by plastic deformation of the metal pipe so as to be connected with end sections of the hollow rod section. The fastening section includes a pair of base end sections which are each connected with a peripheral wall section forming a closed cross-section at the end section of the hollow rod section, and are separated from each other, and a bottom wall including a flat surface connected with the pair of the base end sections, and a pair of front end sections including a pair of side walls curving inwards from at least widthwise end sections of the bottom wall on a base end section side.

A method for manufacturing a stem for a fuel injector of gas turbine engine includes forging a material into a unitary workpiece, which includes forging a top disk having a cylindrical shape, forging a body extending from a base of the top disk, and forging a lower disk connected to the body, distal to the top disk, the lower disk having a cylindrical shape oriented transverse to the top disk. The method further including machining the lower disk to form a gas gallery having a ring shape, and to define a gallery opening through the gas gallery, and machining a first fluid passage through the top disk, the body, and a portion of the gas gallery to the gallery opening, wherein the first fluid passage is in fluid communication with the gallery opening.

A method for manufacturing a stem for a fuel injector of gas turbine engine includes forging a material into a unitary workpiece, which includes forging a top disk having a cylindrical shape, forging a body extending from a base of the top disk, and forging a lower disk connected to the body, distal to the top disk, the lower disk having a cylindrical shape oriented transverse to the top disk. The method further including machining the lower disk to form a gas gallery having a ring shape, and to define a gallery opening through the gas gallery, and machining a first fluid passage through the top disk, the body, and a portion of the gas gallery to the gallery opening, wherein the first fluid passage is in fluid communication with the gallery opening.

A segment adapted to be mounted on a shaft to form a camshaft, wherein the segment comprises a through hole adapted to receive the shaft, and wherein the shape of the hole in the segment is adapted to the cross section of the shaft in such a way that when mounted, the segment has a strain causing it to exert a radial load on the shaft in at least two contact points, wherein an inner surface of the hole has at least one deviation to create at least three contact points between the segment and the shaft, and wherein the at least three contact points are non-uniformly distributed about the circumference of the hole. Advantages include that the camshaft can be made lightweight, with less difficulties and at a lower cost as well as with increased precision in angular positioning of the segment on the shaft.

A camshaft-manufacturing method includes: a split die group preparation step; a processing preparation step of preparing a cam including a through-hole, a cam body which is smaller than each of the cam accommodation portions, and ribs which are provided on both sides in a thickness direction of the cam body and configured to be fitted into the rib accommodation portions, and a hollow shaft, accommodating the cam body in the cam accommodation portion and fitting the ribs in the rib accommodation portion, and inserting the hollow shaft into the through-hole of the cam; and a processing step of performing hydroform processing, and fixing the cam to the hollow shaft by expanding the hollow shaft.

Provided is a connecting rod which can be manufactured without increasing the cost, and is provided with an effectively strengthened rod portion. The rod portion includes a pair of ribs (21) extending in parallel to each other in cross sectional view, and a web (22) connected between substantially vertically middle parts of the ribs. Each rib includes a rib root portion (23) located in a vertically central part thereof in cross sectional view, and a pair of rib tip portions (24) located at both vertical ends thereof, and each rib tip portion has a higher hardness than the web by 40 HV or more, and the rib root portion has a higher hardness than the web by 30 HV or more.

Provided is a connecting rod which can be manufactured without increasing the cost, and is provided with an effectively strengthened rod portion. The rod portion includes a pair of ribs (21) extending in parallel to each other in cross sectional view, and a web (22) connected between substantially vertically middle parts of the ribs. Each rib includes a rib root portion (23) located in a vertically central part thereof in cross sectional view, and a pair of rib tip portions (24) located at both vertical ends thereof, and each rib tip portion has a higher hardness than the web by 40 HV or more, and the rib root portion has a higher hardness than the web by 30 HV or more.

Provided is a metal gasket including, expressed in mass %, C: 0.10% or less, Si: 1.0% or less, Mn: 2.0% or less, P: 0.04% or less (including 0%), S: 0.01% or less (including 0%), Ni: 25.0-60.0%, Cr: 10.0-20.0%, either Mo or W alone, or both Mo+W/2:0.05-5.0%, Al: more than 0.8% to 3.0% or less, Ti: 1.5-4.0%, Nb: 0.05-2.5%, V: 1.0% or less (including 0%), B: 0.001-0.015%, Mg: 0.0005-0.01%, S/Mg: 1.0 or less, N: 0.01% or less (including 0%), and O: 0.005%) or less (including 0%), with the remainder being Fe and unavoidable impurities. The metal gasket has a metal structure in which a precipitate phase having an average equivalent circle diameter of 25 nm or larger is not present within the austenite base.

Provided is a metal gasket including, expressed in mass %, C: 0.10% or less, Si: 1.0% or less, Mn: 2.0% or less, P: 0.04% or less (including 0%), S: 0.01% or less (including 0%), Ni: 25.0-60.0%, Cr: 10.0-20.0%, either Mo or W alone, or both Mo+W/2:0.05-5.0%, Al: more than 0.8% to 3.0% or less, Ti: 1.5-4.0%, Nb: 0.05-2.5%, V: 1.0% or less (including 0%), B: 0.001-0.015%, Mg: 0.0005-0.01%, S/Mg: 1.0 or less, N: 0.01% or less (including 0%), and O: 0.005%) or less (including 0%), with the remainder being Fe and unavoidable impurities. The metal gasket has a metal structure in which a precipitate phase having an average equivalent circle diameter of 25 nm or larger is not present within the austenite base.