| 摘要 |
An adjustable V-belt comprises a compressive rubber layer (2 min ) onto which an adhesion rubber layer (3 min ) is laminated. A surface of the adhesion rubber layer (3 min ) remote from the compressive rubber layer (2 min ) forms an outer surface ofthe V-belt in use and has thereon a plurality of first ridges (4 min ) which extend transversely of the V-belt. A canvas covering (5) covers the first ridges (4 min ) and the recesses defined therebetween, and is stretchable longitudinally of the V-belt. Elongate tensile portions (6 min ) are embedded between the adhesion rubber layer (3 min ) and the first ridges (4 min ) so that they contact portions of the canvas covering (5) which are disposed in said recesses. The tensile portion (6 min ) extend longitudinally of the V-belt in mutually parallel, equi-spaced relation, and have a differential thermal contraction stress between 100 DEG C and 20 DEG C of at least 3.5 g denier. A surface of the compressive rubber layer (2 min ) remote from thc adhesion rubber layer (3 min ) forms an inner surface of the V-belt in use and has a plurality of second ridges (9) thereonwhich also extend transversely of the V-belt. The second ridges (9) can be provided at regular (as shown) or random intervais along the V-belt, and can optionally be covered by at least one ply of rubberized canvas (7 min ). Short fibres (8 min ) can be embedded in the compressive rubber layer (2 min ) so as to be oriented transversely of the V-belt. The V-belt is manufactured by winding the canvas covering (5), the tensile portions (6 min ), the adhesion rubber (3a min ), the compression rubber (2a min ) and (when provided) the rubberized canvas (7 min ) in succession around an outer wall of a cylindrical metal mould (11) which has circumferentially spaced protrusions (12) extending axially thereof. The tensile portions (6 min ) are formed by spirally winding a rope-like tensile member around the mould (11), the tensile member being subjected to a thermal elongation treatment. A hollow cylindrical mould (12) having circumferentially spaced, axially extending protrusions (14) on its inner wall is then placed over the resultant belt blank, and the latter is pressurized and heated. This operation causes some of the adhesion rubber (3a min ) to flow between the windings of the tensile member (6 min ) and into grooves (13) between the protrusions (12) on the firstmentioned cylindrical mould (11), thereby forming the first ridges (4 min ) on the finished V-belt, and also causes some of the compressive rubber (2a min ) to flow into grooves (16) between the protrusions (14) on the hollow cylindrical mould (12), thereby forming the second ridges (9) on the finished V-belt. |
