Abstract: A toothed belt includes an endless back portion, a plurality of belt teeth arranged on a face of the back portion at predetermined intervals in a longitudinal direction of the back portion; and a core made of an elastic knitted or unwoven fabric and embedded in the back portion. Both of the belt teeth and the back portion are made of rubber. The core is not exposed from inter-tooth portions which are located between the belt teeth. In the core, a difference between the position of a point that is closest to the belt teeth in a belt thickness direction and the position of a point that is closest to a back face of the belt in the belt thickness direction is limited to 0.5 mm or less.

Abstract: A notched transmission belt has a plurality of notches whose bottom in a cross-section taken along a plane orthogonal to the width direction of the belt includes a linear portion at a center, and recessed curved portions continuously formed at both sides of the linear portion.

Abstract: A toothed belt includes an endless back portion, a plurality of belt teeth arranged on a face of the back portion at predetermined intervals in a longitudinal direction of the back portion; and a core made of an elastic knitted or unwoven fabric and embedded in the back portion. Both of the belt teeth and the back portion are made of rubber. The core is not exposed from inter-tooth portions which are located between the belt teeth. In the core, a difference between the position of a point that is closest to the belt teeth in a belt thickness direction and the position of a point that is closest to a back face of the belt in the belt thickness direction is limited to 0.5 mm or less.

Abstract: A notched transmission belt has a plurality of notches whose bottom in a cross-section taken along a plane orthogonal to the width direction of the belt includes a linear portion at a center, and recessed curved portions continuously formed at both sides of the linear portion.

Abstract: A top fabric is laminated with an adhesion rubber sheet made of an unvulcanized rubber sheet, which is located on the upper side from a cord of an adhesion rubber layer and forms an upper rubber portion of the adhesion rubber layer, thereby forming a band-shaped laminate. Both longitudinal ends of the band-shaped laminate are butt-jointed with each other so as to produce no level difference at the top surface of the top fabric and at the bottom surface of the adhesion rubber sheet. Thereby, the cord wound around the laminate in the subsequent step is embedded in the adhesion rubber layer without being displaced in level so that the obtained V-ribbed belt produces no abnormal vibration and no noise even if used in serpentine drive.

Abstract: A top fabric 2 which is disposed on the back face of a power transmission belt 1 is obtained by joining a plurality of rubberized fabric pieces 2a, in each of which warps 7 and wefts 8 intersect each other at an obtuse angle which is open toward the direction of the length of the belt, in the shape of a ring. Joining lines of adjacent fabric pieces 2a, 2a both intersect at a right angle with respect to the direction of the length of the belt and are parallel to each other.

Abstract: A top fabric is laminated with an adhesion rubber sheet made of an unvulcanized rubber sheet, which is located on the upper side from a cord of an adhesion rubber layer and forms an upper rubber portion of the adhesion rubber layer, thereby forming a band-shaped laminate. Both longitudinal ends of the band-shaped laminate are butt-jointed with each other so as to produce no level difference at the top surface of the top fabric and at the bottom surface of the adhesion rubber sheet. Thereby, the cord wound around the laminate in the subsequent step is embedded in the adhesion rubber layer without being displaced in level so that the obtained V-ribbed belt produces no abnormal vibration and no noise even if used in serpentine drive.