V-ribbed belt and method for producing same

Patent metadata

Field	Value
Publication number	US-12092188-B2
Application number	US-202017426512-A
Country	US
Kind code	B2
Filing date	Jan 24, 2020
Priority date	Jan 28, 2019
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

A V-ribbed belt includes a compression rubber layer having a frictional power transmission surface that is covered with a fabric. The compression rubber layer includes an inner rubber layer in contact with the fabric and an outer rubber layer on an outer side of the inner rubber layer. The inner rubber layer is formed of a rubber composition having a Mooney Scorch minimum viscosity of 50 to 110 when measured at 125° C., and the outer rubber layer is formed of a rubber composition having a Mooney Scorch minimum viscosity of 70 to 130 when measured at 125° C.

First claim

The invention claimed is:

1. A V-ribbed belt comprising a compression rubber layer having a frictional power transmission surface that is covered with a fabric, the compression rubber layer comprising an inner rubber layer in contact with the fabric and an outer rubber layer on an outer side of the inner rubber layer,
wherein the inner rubber layer is formed of a rubber composition having a Mooney Scorch minimum viscosity of 50 to 110 when measured at 125° C.,
wherein the outer rubber layer is formed of a rubber composition having a Mooney Scorch minimum viscosity of 70 to 130 when measured at 125° C.,
wherein the rubber composition forming the inner rubber layer has a lower Mooney Scorch minimum viscosity than the rubber composition forming the outer rubber layer, and
wherein the V-ribbed belt comprises rib portions extending in a longitudinal direction.

2. The V-ribbed belt according to claim 1 ,
wherein a thickness ratio of the inner rubber layer to the entire compression rubber layer is 1% to 50%.

3. The V-ribbed belt according to claim 1 ,
wherein the rubber composition forming the inner rubber layer contains a hydrophilic plasticizer.

4. The V-ribbed belt according to claim 1 ,
wherein the rubber composition forming the inner rubber layer contains polyolefin particles.

5. The V-ribbed belt according to claim 1 ,
wherein the fabric is impregnated with or adhered to an isocyanate compound.

6. The V-ribbed belt according to claim 1 , further comprising a cord extending in a longitudinal direction of a belt body,
wherein a tensile elastic modulus of fibers constituting the cord is 50 GPa or more.

7. The V-ribbed belt according to claim 1 , comprising:
a belt body comprising at least a tension rubber layer forming a belt back surface and the compression rubber layer laminated on an inner peripheral surface of the tension rubber layer and having rib portions extending in a longitudinal direction;
a cord embedded in the longitudinal direction of the belt body; and
the fabric which is a knitted fabric laminated on the rib portions as the frictional power transmission surface and containing at least cellulose fibers,
wherein the inner rubber layer is formed of the rubber composition having a Mooney Scorch minimum viscosity of 60 to 100 when measured at 125° C.,
wherein the outer rubber layer is formed of the rubber composition having a Mooney Scorch minimum viscosity of 80 to 120 when measured at 125° C.,
wherein the cord is formed of aramid fibers and/or carbon fibers, and
wherein the knitted fabric is impregnated with or adhered to at least a block-type polyisocyanate compound.

8. A method for producing a V-ribbed belt, the method comprising:
disposing, on a cylindrical inner mold disposed in a hollow cylindrical outer mold, an unvulcanized laminate comprising an unvulcanized rubber sheet for compression rubber layer and a fabric laminated on the unvulcanized rubber sheet so that the fabric is directed toward the outer mold;
pressurizing the unvulcanized rubber sheet at least toward the outer mold to vulcanize the unvulcanized rubber sheet; and
demolding a molded body of the vulcanized rubber sheet and the fabric to produce a V-ribbed belt having a predetermined form,
wherein the unvulcanized rubber sheet for compression rubber layer is formed of an unvulcanized rubber sheet for inner rubber layer in contact with the fabric and an unvulcanized rubber sheet for outer rubber layer on an outer side of the unvulcanized rubber sheet for inner rubber layer,
wherein the unvulcanized rubber sheet for inner rubber layer is formed of a rubber composition having a Mooney Scorch minimum viscosity of 50 to 110 when measured at 125° C.,
wherein the unvulcanized rubber sheet for outer rubber layer is formed of a rubber composition having a Mooney Scorch minimum viscosity of 70 to 130 when measured at 125° C.,
wherein the rubber composition forming the inner rubber layer has a lower Mooney Scorch minimum viscosity than the rubber composition forming the outer rubber layer, and
wherein the V-ribbed belt comprises rib portions extending in a longitudinal direction.

9. The method according to claim 8 , wherein the unvulcanized rubber sheet is pressurized and vulcanized at a pressure of 1.2 MPa or more.

10. The method according to claim 8 ,
wherein the unvulcanized rubber sheet for compression rubber layer is prepared by rolling an unvulcanized rubber sheet with a calender roll to form the unvulcanized rubber sheet for inner rubber layer which forms a frictional power transmission surface, and laminating the unvulcanized rubber sheet for inner rubber with the unvulcanized rubber sheet for outer rubber layer on the calender roll.

11. The method according to claim 8 , comprising:
disposing the unvulcanized laminate which is a hollow cylindrical or sleeve-shaped unvulcanized laminate comprising:
an unvulcanized rubber laminated sheet for forming a belt body comprising at least the unvulcanized rubber sheet for compression rubber layer and an unvulcanized rubber sheet for tension rubber layer laminated or disposed on one surface of the unvulcanized rubber sheet for compression rubber layer;
a cord embedded in a longitudinal direction of the unvulcanized rubber laminated sheet; and
the fabric which is a knitted fabric laminated or disposed on the other surface of the unvulcanized rubber sheet for compression rubber layer,
so that the knitted fabric is directed toward a rib mold of the outer mold; and
pressurizing and vulcanizing the unvulcanized rubber laminated sheet with an expansion pressure of a flexible jacket that is mounted on the inner mold and is expandable and contractile.

12. The V-ribbed belt according to claim 1 , wherein the inner rubber layer is formed separately from and disposed in contact with the fabric.

13. The V-ribbed belt according to claim 1 , wherein the Mooney Scorch minimum viscosity of the rubber composition forming the inner layer is 10 to 30 lower than the Mooney Scorch minimum viscosity of the rubber composition forming the outer layer.

14. The method according to claim 8 , wherein the inner rubber layer is formed separately from and disposed in contact with the fabric.

15. The method according to claim 8 , wherein the Mooney Scorch minimum viscosity of the rubber composition forming the inner layer is adjusted to be 10 to 30 lower than the Mooney Scorch minimum viscosity of the rubber composition forming the outer layer.

Assignees

• Mitsuboshi Belting Ltd

Inventors

• Mitsutomi Manabu
• KAMBA Yuji
• Hineno Yorifumi

Classifications

• F16G5/20

  with a contact surface of special shape, e.g. toothed · CPC title

• B29D29/103

  Multi-ribbed driving belts · CPC title

• F16G5/08 Primary

  with textile reinforcement · CPC title