Method for producing V-ribbed belt

A method for producing a V-ribbed belt including a compressed rubber layer which forms an inner peripheral portion of the V-ribbed belt in a thickness direction of the V-ribbed belt, and which has a plurality of V-shaped ribs extending in a longitudinal direction of the V-ribbed belt and arranged in a width direction of the V-ribbed belt, the plurality of V-shaped ribs having a friction drive surface covered with a surface rubber layer, the method comprising:

• setting a shaped structure and a surface rubber sheet which is to constitute the surface rubber layer in a belt mold such that the shaped structure and the surface rubber sheet are respectively positioned inside and outside with respect to each other, the shaped structure having a cylindrical shape, being made of an uncrosslinked rubber composition, including, on an outer peripheral surface thereof, a plurality of ridges extending in a circumferential direction and arranged adjacent to each other in an axial direction of the shaped structure, the belt mold including a plurality of compressed rubber layer-shaping grooves arranged in a groove width direction;
• molding a cylindrical belt slab by crosslinking the shaped structure set in the belt mold through heating and pressing the shaped structure toward the belt mold, while each of compressed rubber layer-forming portions is fitted in an associated one of the compressed rubber layer-shaping grooves of the belt mold, the compressed rubber layer-forming portions being comprised of the plurality of ridges, of the shaped structure, each covered with the surface rubber sheet and together forming the compressed rubber layer, the crosslinking involving integration of the shaped structure with the surface rubber sheet;
• and
• cutting the belt slab into ring-shaped pieces each including two or more of the plurality of compressed rubber layer-forming portions that are to constitute the plurality of V-shaped ribs, wherein
• prior to setting the shaped structure and the surface rubber sheet in the belt mold, the ridges are covered with the surface rubber sheet, thereby forming the compressed rubber layer-forming portions,
• before the ridges are covered with the surface rubber sheet, the surface rubber sheet is shaped to have a corrugated cross section having same pitches as those of the ridges, and then, disposed such that portions of the surface rubber sheet protruding toward the ridges are positioned at grooves between the ridges, and
• the surface rubber sheet which originally has a flat shape is continuously passed between a pair of plate-shaped or rolled members configured to pleat the surface rubber sheet, so that pitches of the surface rubber sheet pleated gradually decrease in a length direction.

A method for producing a V-ribbed belt including a compressed rubber layer which forms an inner peripheral portion of the V-ribbed belt in a thickness direction of the V-ribbed belt, and which has a plurality of V-shaped ribs extending in a longitudinal direction of the V-ribbed belt and arranged in a width direction of the V-ribbed belt, the plurality of V-shaped ribs having a friction drive surface covered with a surface rubber layer, the method comprising:

• forming a shaped structure having a cylindrical shape, being made of an uncrosslinked rubber composition, and including, on an outer peripheral surface thereof, a plurality of ridges extending in a circumferential direction and arranged adjacent to one another in an axial direction of the shaped structure;
• after formation of the ridges, forming compressed rubber layer-forming portions, which are to constitute the V-shaped ribs, by covering each of the ridges with the surface rubber sheet, which is to constitute the surface rubber layer;
• molding a cylindrical belt slab by using a belt mold including a plurality of compressed rubber layer-shaping grooves arranged in a groove width direction, and by crosslinking the shaped structure, which has been formed in the forming the shaped structure, through heating and pressing the shaped structure toward the belt mold, while each of compressed rubber layer-forming portions, which have been formed in the forming the compressed rubber layer-forming portions, is fitted in an associated one of the compressed rubber layer-shaping grooves of the belt mold, the crosslinking involving integration of the shaped structure with the surface rubber sheet;
• and
• cutting the belt slab into ring-shaped pieces each including two or more of the plurality of compressed rubber layer-forming portions that are to constitute the plurality of V-shaped ribs.