# US 11,906,016 B2 · V-ribbed belt and application thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,016 B2 - Document ID: US11906016B2 - Status: Granted - Kind: B2 - Application number: 17/050,995 - Filed: 2019-04-25 - Published: 2021-07-29 - Granted: 2024-02-20 - Earliest claimed: 2018-04-27 - Assignees: Mitsuboshi Belting Ltd. - Applicants: Mitsuboshi Belting Ltd. - Inventors: Hiroki Imai; Yuji Maruyama; Arata Hasegawa - Web page: https://patentgrep.com/patent/US11906016B2 ## CPC - F16G 5/08: with textile reinforcement - F16G 5/20: with a contact surface of special shape, e.g. toothed - C08L 23/16: Ethylene-propylene or ethylene-propylene-diene copolymers - F16G 5/06: with reinforcement bonded by the rubber - F16H 7/02: with belts; with V-belts - C08L 2205/03: containing three or more polymers in a blend - F16G: BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - F16H: GEARING ## Abstract In a V-ribbed belt provided with a compressed rubber layer having V-ribbed portions extending parallel to one another in a belt longitudinal direction, and having a friction transmission surface at least a portion of which is capable of coming into contact with a V-ribbed groove portion of a pulley, the friction transmission surface of the compressed rubber layer is formed from a rubber composition vulcanizate including a rubber component and a sound generation resistance improving agent. A difference between a radius of curvature of a rib distal end portion of the pulley and a radius of curvature of a rib bottom portion of the belt is adjusted to be −0.08-0.08 mm. The radius of curvature of the rib bottom portion may be approximately 0.1-0.5 mm. The radius of curvature difference may be −0.05-0.05 mm. The pulley may include a pulley having an outer diameter at most equal to 65 mm. ## Claims ### Claim 1 A V-ribbed belt comprising: a plurality of V-rib portions extending along a longitudinal direction of the V-ribbed belt and in parallel with one another; and a compression rubber layer comprising a frictional power transmission face at least a part of which is configured to come into contact with a V-rib groove portion of a pulley, wherein the frictional power transmission face of the compression rubber layer is formed from a vulcanizate of a rubber composition containing a rubber component and a noise suppression improver, and a difference between a curvature radius of a rib top end of the pulley and a curvature radius of a rib bottom portion of the V-ribbed belt is −0.08 to 0.08 mm. ### Claim 2 (depends on 1) The V-ribbed belt according to claim 1, wherein the curvature radius of the rib bottom portion of the V-ribbed belt is 0.1 to 0.5 mm. ### Claim 3 (depends on 1) The V-ribbed belt according to claim 1, wherein the difference between the curvature radii is −0.05 to 0.05 mm. ### Claim 4 (depends on 1) The V-ribbed belt according to claim 1, wherein the pulley includes a pulley having an outer diameter of 65 mm or smaller. ### Claim 5 (depends on 1) The V-ribbed belt according to claim 1, wherein each V-rib portion of the V-ribbed belt has a V-rib angle of 30° to 60°, and a difference between the V-rib angle and a V-rib groove angle of the pulley is −1° to 1°. ### Claim 6 (depends on 1) The V-ribbed belt according to claim 1, wherein the noise suppression improver is at least one kind selected from the group consisting of a surfactant, a plasticizer having a larger solubility parameter than the rubber component, inorganic particles, and polyethylene resin particles. ### Claim 7 (depends on 1) The V-ribbed belt according to claim 1, wherein the noise suppression improver contains a polyethylene glycol nonionic surfactant, and a proportion of the polyethylene glycol nonionic surfactant is 2 to 20 parts by mass relative to 100 parts by mass of the rubber component. ### Claim 8 (depends on 1) The V-ribbed belt according to claim 1, wherein the noise suppression improver contains an ether ester plasticizer, and a proportion of the ether ester plasticizer is 5 to parts by mass relative to 100 parts by mass of the rubber component. ### Claim 9 (depends on 1) The V-ribbed belt according to claim 1, wherein the rubber component contains an ethylene-α-olefin elastomer. ### Claim 10 (depends on 1) A belt power-transmission apparatus comprising: the V-ribbed belt according to claim 1; and each pulley having a V-rib groove portion capable of fitting to one of the V-rib portions of the V-ribbed belt, wherein the difference between the curvature radius of the rib top end of the pulley and the curvature radius of the rib bottom portion of the V-ribbed belt is −0.08 to 0.08 mm. ### Claim 11 (depends on 10) The belt power-transmission apparatus according to claim 10, wherein the pulley includes a pulley having an outer diameter of 65 mm or smaller. ### Claim 12 A method for reducing torque loss of a belt power-transmission apparatus, the method comprising: hanging a V-ribbed belt on a pulley, the V-ribbed belt comprising: a plurality of V-rib portions extending along a longitudinal direction of the V-ribbed belt and in parallel with one another; and a compression rubber layer comprising a frictional power transmission face at least a part of which is configured to come into contact with a V-rib groove portion of the pulley, wherein the frictional power transmission face of the compression rubber layer is formed from a vulcanizate of a rubber composition containing a rubber component and a noise suppression improver, a difference between a curvature radius of a rib top end of the pulley and a curvature radius of a rib bottom portion of the V-ribbed belt is −0.08 to 0.08 mm, and wherein the pulley includes a pulley having an outer diameter of 65 mm or smaller.