JP2020159410A - Cogged v belt - Google Patents

Abstract

To provide a cogged V belt having excellent durability in both low-speed and high-speed power transmission.SOLUTION: In a cogged V belt B, a ratio (PL/RL) of an arrangement pitch PL of the lower cog 16 to a radius of curvature RL of a valley 17 formed between lower cogs 16 adjacent to each other is 7.5 or more and 22.5 or less, and a ratio (AL/BL) of a distance AL from a buried center position of a core wire 12 in a belt thickness direction to the top part of the lower cog 16 to a distance BL from the buried center position of the core wire 12 to the deepest part of the valley 17 is 2.0 or more.SELECTED DRAWING: Figure 1B

Description

The present invention relates to a cogged V-belt.

A cogged V-belt is used as a speed change belt used for a continuously variable transmission such as a two-wheeled vehicle. For example, Patent Documents 1 and 2 disclose a speed change belt of a double-cogged V-belt in which a lower cog and an upper cog are arranged at a constant pitch in the belt length direction on the inner peripheral side of the belt and the outer peripheral side of the belt, respectively. ..

Japanese Patent No. 6271791 Japanese Patent No. 6313991

An object of the present invention is to provide a cogged V-belt having excellent durability in both low speed and high speed power transmission.

The present invention is a cogged V-belt having a lower cog on the inner peripheral side of the belt, and when a part of the cogged V-belt is extended straight, it is configured between the lower cogs adjacent to each other in the side view of the part. The ratio of the arrangement pitch of the lower cog to the radius of curvature of the lower cog valley portion is 7.5 or more and 22.5 or less, and the lower cog valley portion is located from the embedding center position of the core wire in the belt thickness direction. The ratio of the distance from the buried center position of the core wire to the top of the lower cog with respect to the distance to the deepest portion is 2.0 or more.

According to the present invention, the ratio of the arrangement pitch of the lower cog to the radius of curvature of the lower cog valley portion is 7.5 or more and 22.5 or less, and the lower cog valley is from the buried center position of the core wire in the belt thickness direction. When the ratio of the distance from the center position of the core wire to the top of the lower cog to the distance to the deepest part of the part is 2.0 or more, excellent durability is obtained in both low speed and high speed power transmission. be able to.

It is a perspective view which shows the piece of the double cogged V belt which concerns on embodiment. It is a side view of a part extended straight in the double cogged V-belt which concerns on embodiment. It is sectional drawing of the part which extended straight in the double cogged V-belt which concerns on embodiment. It is a side view which shows the low-speed layout of a belt type continuously variable transmission. It is a top view which shows the low-speed layout of a belt type continuously variable transmission. It is a side view which shows the high-speed layout of a belt type continuously variable transmission. It is a top view which shows the high-speed layout of a belt type continuously variable transmission. It is a side view which shows the low-speed layout of a belt running tester. It is a side view which shows the high-speed layout of a belt running tester. It is a graph showing the relationship between the ratio of the curvature radius R _L between the lower cog valley arrangement pitch P _L of the lower cog and (P L _{/ R L)} and low-speed durability life. It is a graph showing the relationship between the ratio of the curvature radius R _L between the lower cog valley arrangement pitch P _L of the lower cog and (P L _{/ R L)} and high speed durability life. A ratio from embedded central position of the cord with respect to the distance B _L from buried central position of the core wire of the distance A _L to the top of the lower cogs deepest between the lower cog valleys (A L _{/ B L)} and the low-speed durability life It is a graph which shows the relationship of. The distance A _L ratio from embedded central position of the cord with respect to the distance B _L of the deepest among the lower cog valleys (A L _{/ B L)} and high-speed durability to the top of the lower cogs from buried central position of the core wire It is a graph which shows the relationship of.

Hereinafter, embodiments will be described in detail with reference to the drawings.

1A-C show the double-cogged V-belt B according to the embodiment. The double cogged V-belt B according to the embodiment is an endless belt used, for example, as a power transmission member for a continuously variable transmission of a motorcycle or a general-purpose machine. The belt length L of the double-cogged V-belt B according to the embodiment is, for example, 500 mm or more and 2000 mm or less.

The double cogged V-belt B according to the embodiment includes a V-belt main body 11, a core wire 12, and a lower cog reinforcing cloth 13.

The V-belt main body 11 is formed of a rubber composition having a cross section along the belt width direction in which an isosceles trapezoid on the inner circumference side of the belt and a horizontally long rectangle on the outer circumference side of the belt are laminated. .. The side surfaces on both sides of the V-belt body 11 correspond to an inclined surface extending inwardly in the belt thickness direction corresponding to the oblique side of the isosceles trapezoidal cross-sectional shape, and a short side of the horizontally long rectangular cross-sectional shape. It has vertical surfaces extending in the thickness direction of the belt, and the inclined surface thereof is formed as a pulley contact surface. When a part of the double cogged V-belt B according to the embodiment is straightened, the maximum width W of the belt is, for example, 10.0 mm or more and 50.0 mm or less, and the maximum thickness T of the belt is, for example, 10.0 mm or more. It is 0 mm or less. The belt V angle θ formed by the inclined surfaces on both sides is, for example, 24.0 ° or more and 36.0 ° or less.

The V-belt main body 11 has a compression rubber layer 111 on the inner peripheral side of the belt, an adhesive rubber layer 112 in the middle portion, and an stretch rubber layer 113 on the outer peripheral side of the belt. The compressed rubber layer 111, the adhesive rubber layer 112, and the stretched rubber layer 113 are uncrosslinked rubber compositions in which various rubber compounding agents such as crosslinkers are mixed with rubber components such as chloroprene rubber (CR) and kneaded. It is formed of a rubber composition that has been crosslinked by heating and pressurizing.

On the inner peripheral side of the belt of the compressed rubber layer 111, lower cog forming portions 111a of the ridges having a parabolic outer shell formed in a parabolic shape and extending in the belt width direction are arranged at a constant pitch in the belt length direction. .. On the outer peripheral side of the belt of the stretch rubber layer 113, upper cogs 14 of ridges having a rectangular outer shape in the side view and extending in the belt width direction are arranged at a constant pitch in the belt length direction. Between the upper cogs 14 adjacent to each other, an upper cog valley portion 15 having a parabolic outer shell formed by a groove extending in the belt width direction is formed.

The core wire 12 is embedded in the intermediate portion of the adhesive rubber layer 112 of the V-belt main body 11 in the thickness direction so as to form a spiral in the belt width direction. The core wire 12 is composed of, for example, a twisted yarn of polyester fiber or aramid fiber. The diameter of the core wire 12 is, for example, 0.8 mm or more and 1.6 mm or less. The belt width (belt pitch width) w at the buried center position (belt pitch line) L of the core wire 12 in the belt thickness direction is, for example, 9.0 mm or more and 49.0 mm or less. It is preferable that the core wire 12 is subjected to an adhesive treatment for imparting adhesiveness to the adhesive rubber layer 112.

The lower cog reinforcing cloth 13 is provided so as to cover the inner peripheral side surface of the compressed rubber layer 111 of the V-belt main body 11. The lower cog reinforcing cloth 13 is made of, for example, a woven cloth made of nylon fibers. The thickness of the lower cog reinforcing cloth 13 is, for example, 0.2 mm or more and 1.0 mm or less. It is preferable that the lower cog reinforcing cloth 13 is subjected to an adhesive treatment for imparting adhesiveness to the compressed rubber layer 111.

The lower cog reinforcing cloth 13 covers the lower cog forming portion 111a of the compressed rubber layer 111, whereby the lower cog 16 of the ridge extending in the belt width direction in which the outer shell in the side view is formed in a parabolic shape is formed. ing. Further, between the lower cogs 16 adjacent to each other, a lower cog valley portion 17 formed by a groove extending in the belt width direction in which the outer shell in the side view is formed in a parabolic shape is formed.

For double cogged V-belt B according to the embodiment, when the straight extending portions thereof, in a side view of a portion thereof, mounting pitch P _U of the upper cog 14 in the belt length direction, from the viewpoint of obtaining excellent durability It is preferably 7.5 mm or more and 11.5 mm or less, and more preferably 8.0 mm or more and 11.0 mm or less. Distance from the deepest of the upper cogs between valleys 15 in the belt thickness direction to the top of the upper cogs 14, i.e., the height H _U of upper cogs 14, from the viewpoint of obtaining excellent durability, preferably at least 2.0mm It is 6.0 mm or less, more preferably 3.0 mm or more and 5.0 mm or less. Distance _{A U} from buried center position of the core wire 12 in the belt thickness direction to the top of the upper cogs 14, from the viewpoint of obtaining excellent durability, preferably 2.5mm or more 10.0mm or less, more preferably 4. It is 0 mm or more and 8.0 mm or less. Distance B _U from buried center position of the core wire 12 in the belt thickness direction to the deepest of the upper cogs between valleys 15 have excellent from the viewpoint of obtaining a durable, preferably 0.5mm or more 4.0mm or less, more preferably Is 1.0 mm or more and 3.0 mm or less. The radius of curvature _{R U} of upper cogs between valleys 15, from the viewpoint of obtaining excellent durability, preferably 0.5mm or more 4.0mm or less, more preferably 1.0mm or more 3.5mm or less.

Arrangement pitch _P ratio of curvature radius _{R U} cogs between valleys 15 of the _U of the upper cog 14 _(P U / _{R U),} from the viewpoint of obtaining excellent durability, 15.0 preferably 2.0 or more , More preferably 3.0 or more and 7.0 or less. The ratio with respect to the distance B _U from buried central position of the distance A _U cores 12 from embedding center position of the core wire 12 in the belt thickness direction to the top of the upper cog 14 to the deepest of the upper cogs between valleys 15 (A _U / _BU ) is preferably 2.0 or more and 5.0 or less, more preferably 2.5 or more and 4.0 or less, from the viewpoint of obtaining excellent durability.

For double cogged V-belt B according to the embodiment, when the straight extending portions thereof, in a side view of a portion thereof, mounting pitch P _L of the lower cog 16 in the belt length direction, from the viewpoint of obtaining excellent durability It is preferably 7.0 mm or more and 15.0 mm or less, and more preferably 9.5 mm or more and 13.5 mm or less. Arrangement pitch P _L of the lower cog 16, from the viewpoint of obtaining excellent durability, is preferably larger than the arrangement pitch P _U of upper cogs 14.

The distance from the deepest part of the lower cog valley portion 17 in the belt thickness direction to the top of the lower cog 16, that is, the height _HL of the lower cog 16 is preferably 4.0 mm or more from the viewpoint of obtaining excellent durability. It is 10.0 mm or less, more preferably 5.5 mm or more and 8.5 mm or less. The height H _L of the lower cog 16, from the viewpoint of obtaining excellent durability, it is preferably higher than the height H _U of upper cogs 14.

Distance _{A L} from the buried central position of the core wire 12 to the top of the lower cogs 16 in the belt thickness direction, from the viewpoint of obtaining excellent durability, less preferably at least 8.0 mm 15.0 mm, more preferably 9. It is 0 mm or more and 14.0 mm or less. Distance A _L from the buried central position of the core wire 12 to the top of the lower cogs 16, from the viewpoint of obtaining excellent durability, than the distance A _U from buried center position of the core wire 12 to the top of the upper cog 14 Larger is preferred.

The distance _BL from the buried center position of the core wire 12 in the belt thickness direction to the deepest portion of the lower cog valley portion 17 is preferably 1.0 mm or more and 7.0 mm or less, more preferably, from the viewpoint of obtaining excellent durability. Is 2.0 mm or more and 6.0 mm or less. The distance _BL from the buried center position of the core wire 12 to the deepest part of the lower cog valley portion 17 is from the buried center position of the core wire 12 to the deepest portion of the upper cog valley portion 15 from the viewpoint of obtaining excellent durability. it is preferably larger than the distance B _U of.

The radius of curvature _RL of the lower cog valley portion 17 is preferably 0.2 mm or more and 2.0 mm or less, and more preferably 0.4 mm or more and 1.5 mm or less, from the viewpoint of obtaining excellent durability. The radius of curvature R _L of the lower cog between valleys 17, from the viewpoint of obtaining excellent durability, greater than the radius of curvature R _U of upper cogs between valleys 15 are preferred.

The ratio of curvature radius _{R L} of the arrangement pitch _{P L} of the lower cogs between valleys 17 of the lower cog 16 _(P L / _{R L)} is 7.5 to 22.5 or less, from the viewpoint of obtaining excellent durability It is preferably 8.5 or more and 22.5 or less, and more preferably 9.0 or more and 22.0 or less. The ratio of curvature radius _{R L} of the lower cogs between valleys 17 of the arrangement pitch _{P L} of the lower cog 16 _(P L / _{R L),} from the viewpoint of obtaining excellent durability, arrangement pitch _{P U} of upper cogs 14 greater than the ratio _{(P U} / _R U) for the curvature radius _{R U} on cogs between valleys 15 that are preferred.

The ratio from the buried central position of the core wire 12 in the belt thickness direction with respect to the distance B _L from buried center position of the core wire 12 of the distance A _L to the top of the lower cog 16 to the deepest bottom cogs between valleys 17 (A _L / _BL ) is 2.0 or more, preferably 2.0 or more and 5.0 or less, and more preferably 3.0 or more and 4.0 or less from the viewpoint of obtaining excellent durability. The ratio from the buried central position of the core wire 12 with respect to the distance B _L from buried center position of the core wire 12 of the distance A _L to the top of the lower cog 16 to the deepest bottom cogs between valleys 17 (A L _/ B _L) has excellent from the viewpoint of obtaining the durability, the distance from the buried central position of the distance a _U cores 12 from embedding center position of the core wire 12 to the top of the upper cog 14 to the deepest of the upper cogs between valleys 15 B It is preferably larger than the ratio to _U ( _AU / _BU ).

The double cogged V-belt B according to the embodiment having the above configuration can be manufactured by a known method disclosed in International Publication No. 2015/045255 and the like.

2A and 2B and 3A and 3B show a belt-type continuously variable transmission 20 using the double-cogged V-belt B according to the embodiment.

The belt-type continuously variable transmission 20 includes a drive shaft 21 and a driven shaft 22 arranged in parallel with the drive shaft 21. A drive pulley 23 is provided on the drive shaft 21, and a driven pulley 24 having the same diameter as the drive pulley 23 is provided on the driven shaft 22. The drive pulley 23 has a fixed sheave 23a that is rotatably and non-slip fixed on the drive shaft 21 and a movable sheave 23b that is rotatably and slidably supported so as to face the fixed sheave 23a. Similarly, the driven pulley 24 has a fixed sheave 24a that is rotatably and non-slip fixed on the driven shaft 22 and a movable sheave 24b that is rotatably and slidably supported so as to face the fixed sheave 24a. .. Each of the drive pulley 23 and the driven pulley 24 has a V-groove formed between the fixed sheaves 23a and 24a and the movable sheaves 23b and 24b, and a double-cogged V-belt B is wound between these V-grooves.

The belt-type continuously variable transmission 20 transmits the power supplied to the drive shaft 21 to the driven shaft 22 via the double-cogged V-belt B, and at this time, the winding diameter and the driven of the double-coged V-belt B on the drive pulley 23. By changing the winding diameter around the pulley 24, the output from the drive shaft 21 to the driven shaft 22 is changed. Here, the winding diameter of the double cogged V-belt B around the drive pulley 23 or the driven pulley 24 is the buried center position of the core wire 12 in the side view of the double cogged V-belt B wound around the drive pulley 23 or the driven pulley 24. The radius of curvature of the belt pitch line) L is doubled.

Specifically, as shown in FIGS. 2A and 2B, when the movable sheave 23b is moved away from the fixed sheave 23a of the drive pulley 23 and the movable sheave 24b is brought close to the fixed sheave 24a of the driven pulley 24, the double cogged V-belt B becomes The winding diameter on the drive pulley 23 is smaller than the winding diameter on the driven pulley 24, and as a result, the double cogged V-belt B runs at a low speed. On the contrary, as shown in FIGS. 3A and 3B, when the movable sheave 23b is brought close to the fixed sheave 23a of the drive pulley 23 and the movable sheave 24b is moved away from the fixed sheave 24a of the driven pulley 24, the drive pulley of the double cogged V-belt B is driven. The winding diameter around 23 is larger than the winding diameter around the driven pulley 24, and as a result, the double cogged V-belt B runs at high speed.

According to double cogged V-belt B according to an embodiment of the above configuration, as described above, the ratio of curvature radius R _L of the arrangement pitch P _L of the lower cogs between valleys 17 of the lower cog 16 (P L _/ R _L) There is 7.5 to 22.5 or less, and the belt thickness direction valley between the lower cogs from buried center position of the core wire 12 from the buried central position of the distance a _L cord 12 to the top of the lower cogs 16 at 17 When the ratio ( _AL / _BL ) to the distance _BL to the deepest part of is 2.0 or more, excellent durability can be obtained in both low speed and high speed power transmission.

This is because the ratio of the curvature radius _{R L} of the arrangement pitch _{P L} of the lower cogs between valleys 17 of the lower cog 16 _(P L / _{R L)} is 7.5 or more 22.5 or less, at the time of low-speed running, while securing the contact area with the pulley, the stress concentration on the lower cogs between valleys 17 can be suppressed, while the heart of the distance a _L from the buried central position of the core wire 12 in the belt thickness direction to the top of the lower cogs 16 Since the ratio ( _AL / _BL ) to the distance _BL from the buried center position of the line 12 to the deepest part of the lower cog valley 17 is 2.0 or more, the lower cog valley 17 can be reached during high-speed driving. It is considered that this is because the occurrence of large distortion is suppressed.

In the above embodiment, the double cogged V belt B having the upper cog 14 on the outer peripheral side of the belt and the lower cog 16 on the inner peripheral side of the belt is used, but the present invention is not particularly limited to this, and the single cogged V having no upper cog. It may be a belt.

In the above embodiment, the upper cog 14 has a structure in which the rubber composition of the compressed rubber layer 111 is exposed on the outer peripheral side of the belt, but the present invention is not particularly limited to this, and the upper cog is the rubber composition of the compressed rubber layer. It may be covered with a reinforcing cloth.

(Double cogged V belt)
Double cogged V-belts of Examples 1 to 6 and Comparative Examples 1 to 7 having the dimensional configurations shown in Tables 1 and 2 were produced.

(Test method)
<Low speed durability test>
As shown in FIG. 4A, each of the double-cogged V-belts B of Examples 1 to 6 and Comparative Examples 1 to 7 is wound around the drive pulley 31 of the belt running tester 30 having a low-speed layout with a winding diameter of 100 mm. The driven pulley 32 was wound with a winding diameter of 270 mm, belt tension was applied, the ambient temperature was 70 ° C., the drive pulley 31 was rotated at a rotation speed of 5000 rpm, and the belt was run until it was damaged. The speed ratio (ratio) of the drive pulley 31 and the driven pulley 32 was 2.5. Then, the belt running time from the start of belt running to the breakage is defined as the low-speed endurance life. The required quality is that this low speed endurance life is 90 hours or more.

<High-speed durability test>
As shown in FIG. 4B, each of the double-cogged V-belts B of Examples 1 to 6 and Comparative Examples 1 to 7 is wound around the drive pulley 31 of the belt running tester 30 having a high-speed layout with a winding diameter of 220 mm. The driven pulley 32 was wound with a winding diameter of 164 mm, belt tension was applied, the ambient temperature was 70 ° C., the drive pulley 31 was rotated at a rotation speed of 8000 rpm, and the belt was run until it was damaged. The speed ratio (ratio) of the drive pulley 31 and the driven pulley 32 was 0.8. Then, the belt running time from the start of belt running to the breakage is defined as the high-speed durable life. The required quality is that this high-speed durable life is 300 hours or more.

(Test results)
The test results are shown in Table 1. 5A and B show a relationship between the ratio of the curvature radius R _L of the valley between the lower cog arrangement pitch P _L of the lower cog and (P L _{/ R L)} and low-speed endurance life and high speed durability life. 6A and B, the ratio of buried central position of the cord with respect to the distance B _L from buried central position of the core wire of the distance A _L to the top of the lower cogs deepest between the lower cog valleys (A L _/ B _L ) And the low-speed durable life and the high-speed durable life are shown.

According to these, it can be seen that in each of Examples 1 to 6, the low-speed endurance life is 90 hours or more and the high-speed endurance life is 300 hours or more. On the other hand, in Comparative Examples 1 to 7, it can be seen that the low-speed endurance life is less than 90 hours or the high-speed endurance life is less than 300 hours.

The present invention is useful in the technical field of cogged V-belts.

B Double cogged V belt 11 Belt body 111 Compressed rubber layer 111a Lower cog forming part 112 Adhesive rubber layer 113 Stretch rubber layer 12 Core wire 13 Lower cog reinforcing cloth 14 Upper cog 15 Upper cog valley part 16 Lower cog 17 Lower cog valley part 20 Belt Continuously variable transmission 21 Drive shaft 22 Driven shaft 23 Driven pulley 23a Fixed sheave 23b Movable sheave 24 Driven pulley 24a Fixed sheave 24b Movable sheave 30 Belt running tester 31 Drive pulley 32 Driven pulley

Claims (6)

A cogged V-belt with a lower cog on the inner circumference of the belt.
When a part of the cogged V-belt is stretched straight, the ratio of the arrangement pitch of the lower cogs to the radius of curvature of the lower cog valley portion formed between the lower cogs adjacent to each other in the side view of the part is 7.5 or more and 22.5 or less, and the distance from the embedding center position of the core wire in the belt thickness direction to the top of the lower cog from the embedding center position of the core wire to the deepest part of the lower cog valley portion. Cogged V-belt with a ratio of 2.0 or more to the distance. In the cogged V-belt according to claim 1,
A cogged V-belt having a lower cog arrangement pitch of 7.0 mm or more and 15.0 mm or less. In the cogged V-belt according to claim 1 or 2.
A cogged V-belt having a radius of curvature of 0.2 mm or more and 2.0 mm or less at the lower cog valley portion. In the cogged V-belt according to any one of claims 1 to 3.
A cogged V-belt in which the distance from the buried center position of the core wire to the top of the lower cog is 8.0 mm or more and 15.0 mm or less. In the cogged V-belt according to any one of claims 1 to 4.
A cogged V-belt in which the distance from the buried center position of the core wire to the deepest portion of the lower cog valley portion is 1.0 mm or more and 7.0 mm or less. In the cogged V-belt according to any one of claims 1 to 5,
A cogged V-belt with an upper cog on the outer peripheral side of the belt.

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