Disclosed is a method for manufacturing an endless belt, of the flat type made of metal material, designed to be wound around at least one indexed pulley provided with teeth. The endless belt includes, for the one part, locations which are each designed to receive a product to be conveyed and, for the other part, indexing perforations. The manufacturing method includes the following successive steps: a) a step of supplying a flat band made of the metal material, b) a step of closing the band by welding of the transverse edges thereof via a weld seam, and c) a step of perforating the weld seam, at the at least one longitudinal indexing line, in order to form at least one additional indexing perforation that is also designed to engage with the teeth of the at least one indexed pulley.

Disclosed is a method for manufacturing an endless belt, of the flat type made of metal material, designed to be wound around at least one indexed pulley provided with teeth. The endless belt includes, for the one part, locations which are each designed to receive a product to be conveyed and, for the other part, indexing perforations. The manufacturing method includes the following successive steps: a) a step of supplying a flat band made of the metal material, b) a step of closing the band by welding of the transverse edges thereof via a weld seam, and c) a step of perforating the weld seam, at the at least one longitudinal indexing line, in order to form at least one additional indexing perforation that is also designed to engage with the teeth of the at least one indexed pulley.

A metal ring of a transmission belt in a belt-type continuously variable transmission. A first nitrided layer formed in a main surface of the metal ring, and a second nitrided layer formed in an end surface of the metal ring are included. A thickness of the second nitrided layer is smaller than a thickness of the first nitrided layer, and surface hardness of the end surface is higher than surface hardness of the main surface. Even though the second nitrided layer in the end part is thin, the surface hardness of the end surface is high. Therefore, it is possible to restrain fatigue fracture starting from an end part, and it is also possible to restrain deterioration of abrasion resistance of the end surface.

A metal ring of a transmission belt in a belt-type continuously variable transmission. A first nitrided layer formed in a main surface of the metal ring, and a second nitrided layer formed in an end surface of the metal ring are included. A thickness of the second nitrided layer is smaller than a thickness of the first nitrided layer, and surface hardness of the end surface is higher than surface hardness of the main surface. Even though the second nitrided layer in the end part is thin, the surface hardness of the end surface is high. Therefore, it is possible to restrain fatigue fracture starting from an end part, and it is also possible to restrain deterioration of abrasion resistance of the end surface.

A rear surface of a metal element (23) includes first contact portions (C1) formed on both right and left end sides of an ear portion (26), a second contact portion (C2) formed in a neck portion (25), and a third contact portion (C3) formed in a central portion in a transverse direction in the vicinity of a locking edge (29) of a body portion (24). The first contact portions (C1), the second contact portion (C2), and the third contact portion (C3) can come into contact with a front surface of another adjacent metal element (23) on a rear side. A plate thickness of the metal element (23) in the second contact portion (C2) is smaller than the plate thickness of the metal element (23) in the first contact portions (C1) and is greater than the plate thickness of the metal element (23) in the third contact portion (C3).

A rear surface of a metal element (23) includes first contact portions (C1) formed on both right and left end sides of an ear portion (26), a second contact portion (C2) formed in a neck portion (25), and a third contact portion (C3) formed in a central portion in a transverse direction in the vicinity of a locking edge (29) of a body portion (24). The first contact portions (C1), the second contact portion (C2), and the third contact portion (C3) can come into contact with a front surface of another adjacent metal element (23) on a rear side. A plate thickness of the metal element (23) in the second contact portion (C2) is smaller than the plate thickness of the metal element (23) in the first contact portions (C1) and is greater than the plate thickness of the metal element (23) in the third contact portion (C3).

First and second inclined faces of an inclined face extending radially inward and rearward from a rocking edge formed so as to coincide with a front edge of a saddle face of a body part of a metal element are molded by press forming a metal element material using a mold. An inclined face-corresponding part of the metal element material, which corresponds to the inclined face of the metal element, includes a first inclined face-corresponding portion inclined rearward at a first inclination angle from a rocking edge-corresponding part, and a second inclined face-corresponding portion inclined rearward at a second inclination angle, which is larger than the first inclination angle, from a radially inner end of the first inclined face-corresponding portion. The mold includes a first inclined face-molding portion inclined rearward at the first inclination angle from a rocking edge-molding portion abutting against the rocking edge-corresponding part.

First and second inclined faces of an inclined face extending radially inward and rearward from a rocking edge formed so as to coincide with a front edge of a saddle face of a body part of a metal element are molded by press forming a metal element material using a mold. An inclined face-corresponding part of the metal element material, which corresponds to the inclined face of the metal element, includes a first inclined face-corresponding portion inclined rearward at a first inclination angle from a rocking edge-corresponding part, and a second inclined face-corresponding portion inclined rearward at a second inclination angle, which is larger than the first inclination angle, from a radially inner end of the first inclined face-corresponding portion. The mold includes a first inclined face-molding portion inclined rearward at the first inclination angle from a rocking edge-molding portion abutting against the rocking edge-corresponding part.

An endless metal belt having an excellent abrasion resistance and a method for manufacturing such endless metal belts, capable of sufficiently reducing a tensile stress related to a metal ring in the innermost layer are provided. An endless metal belt includes a belt member formed by laminating a plurality of metal rings; and an element supported by the belt member, in which among the plurality of metal rings, a metal ring in an innermost layer is formed by a maraging steel plate, and another metal ring includes a nitride layer on its surface, and has a specific chemical composition; a tensile strength of the another metal ring is 1,700 MPa or higher; and a surface hardness of the nitride layer is HV800 to HV950.

An endless metal belt having an excellent abrasion resistance and a method for manufacturing such endless metal belts, capable of sufficiently reducing a tensile stress related to a metal ring in the innermost layer are provided. An endless metal belt includes a belt member formed by laminating a plurality of metal rings; and an element supported by the belt member, in which among the plurality of metal rings, a metal ring in an innermost layer is formed by a maraging steel plate, and another metal ring includes a nitride layer on its surface, and has a specific chemical composition; a tensile strength of the another metal ring is 1,700 MPa or higher; and a surface hardness of the nitride layer is HV800 to HV950.