Double cogged V-belt for variable speed drive

1. A V-belt having a number of upper cogs and upper roots with upper pitch and upper curvilinear profile, a number of lower cogs and lower roots with lower pitch and lower curvilinear profile, and a reinforcing tensile layer substantially midway between the upper roots and the lower roots;

with the upper profile symmetric and comprising lines (“L”) and arcs (“A”) connected according to the sequence L 1 -A 1 -L 2 -A 2 -L 3 from the center of any of said upper roots to the center of an adjacent cog of said upper cogs;

with the lower profile symmetric and comprising lines and arcs connected according to the sequence A 3 -L 5 -A 4 -L 6 from the center of any of said lower roots to the center of an adjacent cog of said lower cogs; and

with the sum of the length of L 1 plus the radius of A 1 equal to or within 20% of the radius of A 3 ; and

with at least one of said upper roots being substantially aligned with at least one of said lower roots; and

with both side surfaces of the V-belt including both upper and lower cogs cut at an angle α/2 with respect to the vertical axis of the belt, and with a in the range of approximately 15° to 50° .

2. The V-belt of claim 1 wherein said lines L 1 and L 2 connect tangentially with arc A 1 , and said line L 5 connects tangentially with said arc A 3 .

3. The V-belt of claim 1 wherein the sum of the length of L 1 plus the radius of A 1 is equal to or within 20% greater than the radius of A 3 .

4. The V-belt of claim 1 wherein the included angle of the opposing flanks defined by L 5 of a lower cog is in the range of 10 to 30 degrees, and the included angle of the opposing flanks defined by L 2 of an upper cog is in the range of 10 to 30 degrees.

5. The V-belt of claim 1 wherein

the number of upper cogs and lower cogs are equal, and

the upper and lower profiles are substantially aligned root-to-root.

6. The V-belt of claim 5 wherein the sum of the length of L 1 plus the radius of A 1 is equal to or within 20% greater than the radius of A 3 .

7. The V-belt of claim 6 wherein said lines L 1 and L 2 connect tangentially with arc A 1 , and said line L 5 connects tangentially with arc A 3 .

8. The V-belt of claim 7 wherein the included angle of the opposing flanks defined by L 5 of a lower cog is in the range of 10 to 30 degrees, and the included angle of the opposing flanks defined by L 2 of an upper cog is in the range of 10 to 30 degrees.

9. The V-belt of claim 8 wherein each adjacent arc and line of both the upper and the lower profile are connected tangentially.

10. The V-belt of claim 5 wherein the belt has a top width that is about twice the overall thickness.

11. The V-belt of claim 5 wherein each adjacent arc and line of both the upper and the lower profile connect tangentially.

12. The V-belt of claim 1 wherein the number of upper cogs is greater than the number of lower cogs.

13. The V-belt of claim 12 wherein the number of upper cogs is about 1.1 to 1.3times the number of lower cogs.

14. The V-belt of claim 12 wherein said lines L 1 and L 2 connect tangentially with arc A 1 , and said line L 5 connects tangentially with arc A 3 .

15. The V-belt of claim 12 wherein the included angle of the opposing flanks defined by L 5 of a lower cog is in the range of 10 to 30 degrees, and the included angle of the opposing flanks defined by L 2 of an upper cog is in the range of 10 to 30 degrees.

16. The V-belt of claim 12 wherein the belt has a top width that is about twice the overall thickness.

17. The V-belt of claim 12 wherein each adjacent arc and line of both the upper and the lower profile connect tangentially.

18. The V-belt of claim 1 further comprising opposing side surfaces having a relief angle disposed near a lower cog tip.

19. The V-belt of claim 1 wherein the belt has a top width that is about twice the overall thickness.

20. The V-belt of claim 1 wherein each adjacent arc and line of both the upper and the lower profile connect tangentially.

21. The V-belt of claim 1 wherein at least one of said arcs A 1 , A 2 , A 3 , and A 4 has an arc radius of at least 1 mm.

22. The V-belt of claim 21 wherein each of said arcs A 1 , A 2 , A 3 , and A 4 has an arc radius of at least 1 mm.

23. The V-belt of claim 1 wherein said upper cogs have an upper cog height H 2 , and said lower cogs have a lower cog height Hl, such that H 2 is less than Hl.

24. The V-belt of claim 1 wherein the radius of said arc A 1 is greater than the radius of said arc A 2 , and the radius of said arc A 4 is greater than the radius of said arc A 3 .

25. The V-belt of claim 24 wherein each of said arcs A 1 , A 2 , A 3 , and A 4 has an arc radius of at least 1 mm; and

wherein said upper cogs have an upper cog height H 2 , and said lower cogs have a lower cog height H 1 , such that H 2 is less than Hl.

26. A V-belt having a number of upper cogs and upper roots with upper pitch and upper curvilinear profile, a number of lower cogs and lower roots with lower pitch and lower curvilinear profile, and a reinforcing tensile layer substantially midway between the upper roots and the lower roots;

with the upper profile symmetric and comprising lines (“L”) and arcs (“A”) connected according to the sequence L 1 -A 1 -A 2 -L 3 from the center of any of said upper roots to the center of an adjacent cog of said upper cogs;

with the lower profile symmetric and comprising lines and arcs connected according to the sequence L 4 -A 3 -L 5 -A 4 -L 6 from the center of any of said lower roots to the center of an adjacent cog of said lower cogs; and

with the sum of the length of L 1 plus the radius of A 1 equal to or within 20% of the radius of A 3 ; and

with at least one of said upper roots being substantially aligned with at least one of said lower roots.