Drive belts including foamed undercord layers and methods of manufacturing the same

Patent metadata

Field	Value
Publication number	US-12313145-B2
Application number	US-202118270007-A
Country	US
Kind code	B2
Filing date	Dec 28, 2021
Priority date	Dec 28, 2020
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

A drive belt includes a foamed undercord layer having void spaces located throughout the foamed undercord layer. The void spaces extend from a backing layer of the undercord layer to an exterior surface of the backing layer, and may include some void spaces at the exterior surface that are open to the external environment. The foamed undercord layer may exhibit a 20% reduction in specific gravity as compared to an unfoamed version of the undercord layer. The manufacturing process for making the foamed undercord layer can include incorporating foaming agent in the undercord layer such that the undercord layer both foams and cures when heat and pressure are applied to the undercord layer. The foamed drive belt incorporating the foamed undercord layer may exhibit reduced bending stiffness and improved energy efficiency.

First claim

We claim:

1. A drive belt comprising:
a foamed undercord layer having a thickness extending from a backing layer surface to an exterior surface opposite the backing layer surface, wherein the foamed undercord layer is foamed throughout the entire thickness of the foamed undercord layer;
a plurality of void spaces located throughout the thickness of the foamed undercord layer, the plurality of voids being present throughout the thickness of the foamed undercord layer as a result of the foamed undercord layer being foamed; and
a plurality of cords fully embedded within the foamed undercord layer.

2. The drive belt of claim 1 , wherein at least some of the void spaces present at the exterior surface are open to an external environment.

3. The drive belt of claim 1 , wherein the exterior surface of the foamed undercord layer is in the shape of a plurality of ridges.

4. The drive belt of claim 3 , wherein the plurality of ridges are aligned in parallel to the axis of rotation of the drive belt.

5. The drive belt of claim 3 , wherein the plurality of ridges are aligned perpendicular to the axis of rotation of the drive belt.

6. The drive belt of claim 1 , further comprising chopped fibers dispersed within the foamed undercord layer.

7. The drive belt of claim 1 , wherein the material of the foamed undercord layer directly abuts the plurality of void spaces.

8. The drive belt of claim 1 , further comprising:
a backing layer, the backing layer abutting the backing layer surface of the foamed undercord layer;
and the plurality of cords being aligned perpendicular to the axis of rotation of the drive belt.

9. The drive belt of claim 1 , wherein the foamed undercord layer comprises an elastomer.

10. The drive belt of claim 1 , wherein the specific gravity of the foamed undercord layer is in the range of from 0.6 to 1.1 g/cm3.

11. The drive belt of claim 10 , wherein the specific gravity of the foamed undercord layer is in the range of from 0.8 to 1.0 g/cm3.

12. The drive belt of claim 1 , wherein the drive belt is a profiled drive belt.

13. The drive belt of claim 1 , wherein the specific gravity of the foamed undercord layer is reduced by 10 to 40% as compared to an unfoamed undercord layer, and the bending stiffness of the drive belt decreases as the reduction in specific gravity of the foamed undercord layer is increased.

14. The drive belt of claim 13 , wherein the drive belt has a bending stiffness of between 31 and 38 N/mm at 1 Hz and a bending stiffness of between 34 and 42 N/mm at 10 Hz.

15. A method of manufacturing a drive belt, comprising:
preparing a sheet of uncrosslinked undercord material, the sheet of uncrosslinked undercord material comprising an elastomer and a foaming agent;
applying the sheet of uncrosslinked undercord material to a cylindrical mandrel in at least two layers;
placing cord material in the mold between said at least two layers so that the cord will be embedded within the undercord material in the final belt;
applying heat and pressure to the sheet of uncrosslinked undercord material to thereby cure and foam the sheet of undercord material and form a sleeve of undercord material, the foaming resulting in the creation of a plurality of void spaces throughout the thickness of the sleeve of undercord material;
removing the sleeve of undercord material from the cylindrical mandrel;
cutting the sleeve of undercord material into individual belts;
and grinding or cutting an exterior surface of the individual belts to form a plurality of ridges in the individual belts, the grinding or cutting resulting in some of the plurality of void spaces at an exterior surface of the individual belts being open to the exterior environment.

16. The method of claim 15 , wherein the foaming agent has a decomposition temperature in the range of from 125 deg. C. and 175 deg. C.

17. The method of claim 15 , wherein the sheet of uncrosslinked undercord layer comprises foaming agent at an amount of about 2.5 phr.

18. The method of claim 15 , wherein the sheet of uncrosslinked undercord material further comprises a curing agent.

19. The method of claim 18 , wherein the curing agent is a low-temperature peroxide.

20. The method of claim 15 , wherein the sheet of uncrosslinked undercord material further comprises chopped fibers.

21. The method of claim 20 , wherein the chopped fiber is provided in the sheet of uncrosslinked undercord material at a range of from about 3 to about 40 phr.

22. The method of claim 15 , wherein the sleeve of undercord material has a specific gravity in the range of from 0.6 to 1.1 g/cm3.

23. The method of claim 22 , wherein the sleeve of undercord material has a specific gravity in the range of from 0.8 to 1.0 g/cm3.

24. The method of claim 15 , wherein grinding or cutting the exterior surface of the individual belts to form a plurality of ridges in the individual belts comprises forming the plurality of ridges such that the ridges are aligned perpendicular to the axis of rotation of the individual belts.

25. The method of claim 15 , wherein grinding or cutting the exterior surface of the individual belts to form a plurality of ridges in the individual belts comprises forming the plurality of ridges such that the ridges are aligned parallel to the axis of rotation of the individual belts.

26. The method of claim 15 , wherein the elastomer directly abuts the plurality of void spaces.

Assignees

• Gates Corp

Inventors

• Cheong Tae Hee
• Moss Iii Thomas S
• Ochoa Charles F
• Gerring Douglas G
• Spring Kyle

Classifications

• F16G5/20

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

• F16G5/06

  with reinforcement bonded by the rubber · CPC title

• F16G1/28

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

• B32B2413/00

  Belts · CPC title

• B32B2250/24

  All layers being polymeric · CPC title