JP6949794B2 - Friction transmission belt - Google Patents

Description

The present invention relates to a friction transmission belt.

As a friction transmission belt that transmits power by friction transmission, a V-belt having a V-shaped cross section is generally known. In this V-belt, the friction transmission surface (V-shaped side surface) is formed at a V angle, and tension is applied between the drive pulley and the driven pulley, and the V-shaped side surface comes into contact with the V groove of the pulley. Rotate between the two axes in this state.

V-belts are used in a wide range of fields such as automobiles and industrial machines, and their usage environment and conditions are becoming more and more severe due to an increase in transmission capacity and a compact layout. For example, in a layout with a small diameter pulley or a layout in which forward bending and reverse bending are continuously repeated by being wound around a plurality of pulleys corresponding to diversification of functions, bending fatigue resistance due to strict bending conditions. Is required to be improved.

Conventionally, various methods have been proposed to satisfy these requirements. For example, there are those in which the thickness of the cross-sectional dimension is set thin in order to reduce the bending stress, and those in which cogs (unevenness) are provided on the entire inner circumference side of the belt (see, for example, Patent Documents 1 and 2). ). Further, in order to suppress the occurrence of cracks at the bottom of the belt due to bending fatigue, a woven fabric composed of warp and weft as a plain weave and a wide angle weave, and a cotton and polyester blend as a material has been incorporated as a reinforcing cloth.

Special Fair 05-22093 Japanese Unexamined Patent Publication No. 09-317831

The belt with the above-mentioned conventional configuration is mainly used for domestic medium-sized and small-sized agricultural machines, but in recent years, it has excellent bending fatigue resistance, which can ensure durability even under more severe bending conditions. Development of a belt is required. For example, when attached to a large agricultural machine operating in Europe and the United States, a friction transmission belt having a large cross-sectional area and high rigidity corresponding to a high transmission ability is used. The same applies not only to agricultural machinery but also to large compressors, crushers (crushers), generators, pumps, etc., whose usage conditions are similarly strict. Although such a friction transmission belt is structurally difficult to bend, it is wound around a plurality of pulleys and is subjected to severe bending conditions in which forward bending and reverse bending are continuously repeated, high load, high tension, and long time. It is used under bending conditions where the contact angle of the running and reverse bending pulleys is large and reverse bending is severe. When used under such harsh conditions, the belt of the conventional configuration does not have sufficient durability. In particular, a configuration that can sufficiently withstand bending fatigue caused by reverse bending has not been sufficiently studied.

Therefore, an object of the present invention is to provide a friction transmission belt having excellent bending fatigue resistance, which is less likely to cause cracks even when used under stricter bending conditions, and which has excellent durability.

The friction transmission belt of the present invention is an endless friction transmission belt, which includes a rubber layer formed of a rubber composition and a core layer embedded in the rubber layer along the circumferential direction of the belt. The outer peripheral surface of the friction transmission belt has a concave groove along the circumferential direction of the belt. In the present invention, the "outer peripheral surface of the belt" refers to the surface opposite to the inner peripheral surface in contact with the pulley, that is, the back surface of the belt.

According to the above configuration, since the concave groove extends along the circumferential direction of the belt on the outer peripheral surface of the belt, the bending stress generated in the belt when wound around the pulley is relaxed, and the bending fatigue of the belt is relaxed. Can be suppressed and durability is improved. As a result, the temperature rise of the belt due to self-heating due to bending is suppressed, the deterioration of the rubber is prevented, and cracks are less likely to occur. Therefore, it is possible to obtain a friction transmission belt having excellent durability, which is less likely to crack even under severe bending conditions.

The friction transmission belt of the present invention preferably has a semicircular or semi-elliptical shape of the groove in the cross section including the belt width direction of the friction transmission belt.

According to the above configuration, there are no angles on the inner surface of the groove and the stress distribution is excellent, so that the belt has good bending fatigue resistance. Further, since it has a simple shape, it is easy to process a groove at the time of production.

In the friction transmission belt of the present invention, the width of the groove is preferably 50% to 70% of the belt width.

In the friction transmission belt of the present invention, the groove depth is preferably 5% to 20% of the belt thickness.

The friction transmission belt of the present invention is composed of a high-strength fiber sheet having a structure in which the core body layer intersects fiber bundles extending in two directions.

According to the above configuration, the core layer is composed of high-strength fibers and the core layer has a structure in which fiber bundles extending in two directions intersect, so that the impact is dispersed even if a strong impact is received. Therefore, the strength is increased in both the belt width direction and the belt circumferential direction, and the impact resistance of the friction transmission belt is improved. In addition, the resistance of the friction transmission belt to the lateral pressure received from the V groove of the pulley is also improved. As a result, when the tension of the belt is increased in order to obtain a high transmission ability, even if the belt falls into the pulley, the belt is less likely to be significantly deformed on both sides, and the durability is also improved. Further, since the high-strength fiber sheet is considerably thinner than the conventional core wire, a thin core body layer can be obtained. This improves the flexibility of the friction transmission belt.

In the friction transmission belt of the present invention, at least the outer peripheral surface thereof is covered with an outer cover cloth.

According to the above configuration, it is possible to prevent damage to the periphery of the surface of the friction transmission belt covered with the outer cover, and in particular, it is possible to prevent damage to the periphery of the end of the groove.

The belt width of the friction transmission belt of the present invention is preferably 24.4 mm to 50.8 mm, and the belt thickness of the friction transmission belt of the present invention is preferably 12.7 mm to 22.2 mm.

As described above, according to the present invention, it is possible to provide a friction transmission belt having excellent bending fatigue resistance, which is less likely to crack even when used under stricter bending conditions, and which has excellent durability. can.

It is a schematic block diagram of the power transmission system using the friction transmission belt which concerns on embodiment of this invention. It is a partially enlarged perspective view of the friction transmission belt. It is a figure which shows the standard size of the V-belt for large-scale agricultural machinery used in the United States and Europe. It is sectional drawing which includes the belt width direction of a friction transmission belt. It is a top view of the high-strength fiber sheet before cutting. It is a figure of the cross-sectional shape including the belt width direction of the friction transmission belt which concerns on the modification of this invention. It is sectional drawing which includes the belt width direction of the friction transmission belt which concerns on the modification of this invention. It is a partially enlarged perspective view of the friction transmission belt which concerns on the modification of this invention.

Next, the friction transmission belt 2 according to the embodiment of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 shows a schematic configuration of a power transmission system 1 using the friction transmission belt 2 of the present invention. This power transmission system 1 is, for example, a power transmission system for a large agricultural machine used in the United States and Europe. The friction transmission belt 2 is wound around the drive pulley 3 and the driven pulley 4. The friction transmission belt 2 transmits the power of the drive pulley 3 to the driven pulley 4. Further, a tension pulley 5 is arranged between the drive pulley 3 and the driven pulley 4, and the tension pulley 5 abuts on the outer peripheral surface 9 (back surface) of the friction transmission belt 2 and presses the belt from the outside in the form of reverse bending. It is giving tension.

[Structure of friction transmission belt 2]
Next, the friction transmission belt 2 will be described with reference to FIGS. 2 to 5. The friction transmission belt 2 is an endless V-belt, and has a rubber layer 6, a core body layer 7 embedded in the rubber layer 6, and an outer cover 8 that covers the rubber layer 6. The size of the V-belt for large-scale agricultural machinery used in the United States and Europe is defined by the ASAE standard (American Agricultural Engineering Society), for example, as shown in FIG. According to FIG. 3, the standard size of the V-belt for large agricultural machinery used in the United States and Europe is a belt width of 24.4 mm to 50.8 mm and a belt thickness of 12.7 mm to 22.2 mm. .. The friction transmission belt 2 of the present embodiment also preferably has a belt width of 24.4 mm to 50.8 mm and a belt thickness of 12.7 mm to 22.2 mm.

[Details of rubber layer 6]
As shown in FIG. 2, on the surface of the rubber layer 6 on the outer peripheral side of the belt, one concave groove 10 extending continuously over the entire circumference of the belt is formed along the circumferential direction of the belt.

As shown in FIG. 4, the cross-sectional shape of the concave groove 10 in the cross section including the belt width direction is preferably a semi-elliptical shape. When the cross-sectional shape of the groove 10 is semi-elliptical, there are no angles on the inner surface of the groove 10 and the stress distribution is excellent, so that the belt has good bending fatigue resistance. Further, since it has a simple shape, it is easy to process the groove 10 at the time of production.

As shown in FIG. 4, when the width of the groove 10 is W1 and the belt width is W2, W1 is 50% to 70% of W2 from the viewpoint of appropriate bending fatigue resistance and prevention of breakage. preferable. Further, when the depth of the groove 10 is T1 and the belt thickness of the friction transmission belt 2 is T2, T1 is 5% to 20% of T2 from the viewpoint of appropriate bending fatigue resistance and prevention of breakage. Is preferable.

As the rubber component of the rubber composition forming the rubber layer 6, vulverable or crosslinkable rubber, for example, diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene / butadiene rubber (SBR), acrylonitrile) Butadiene rubber (nitrile rubber), hydride nitrile rubber, etc.), ethylene-α-olefin elastomer, chlorosulphonized polyethylene rubber, alkylated chlorosulphonized polyethylene rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, fluororubber Etc. can be exemplified. These rubber components may be used alone or in combination of two or more. Preferred rubber components are ethylene-α-olefin elastomer (ethylene-α-olefin rubber such as ethylene-propylene copolymer (EPM) and ethylene-propylene-diene ternary copolymer (EPDM)) and chloroprene rubber. .. Examples of the diene monomer of EPDM include dicyclopentadiene, methylenenorbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene and the like. A particularly preferable rubber component is chloroprene rubber, which has an excellent balance in terms of both performance and workability.

Further, in the rubber composition forming the rubber layer 6, if necessary, a cross-linking agent such as sulfur and an organic peroxide, N, N'-m-phenylenedi maleimide, and quinone, which are usually blended in the rubber, are added. Cocrosslinking agents such as dioximes, vulcanization accelerators, fillers such as calcium carbonate and talc, plasticizers, stabilizers, processing aids, colorants, short fibers and the like may be blended. Short fibers include cotton, polyester (PET, PEN, etc.), nylon (6 nylon, 66 nylon, 46 nylon, etc.), aramid (p-aramid, m-aramid), vinylon, polyparaphenylene benzobisoxazole (PBO). Fiber or the like can be used. These short fibers can be used alone or in combination of two or more.

[Details of core layer 7]
The core body layer 7 is embedded in the rubber layer 6. As shown in FIG. 4, the core body layer 7 may be separated from the bottom of the groove 10 and the inner peripheral surface 12 of the friction transmission belt 2 and may be located at the center of the rubber layer 6. As shown in FIG. 4, assuming that the distance between the upper end of the core layer 7 (the end on the outer peripheral side of the belt) and the bottom of the groove 10 is L1, L1 / T2 is particularly preferably 5 to 25%.

The core layer 7 is preferably composed of a high-strength fiber sheet 11 having a structure in which fiber bundles extending in two directions intersect. The core body layer 7 may be composed of one high-strength fiber sheet 11 or a plurality of high-strength fiber sheets 11. As shown in FIG. 4, when the thickness of the core body layer 7 is L2, L2 / T2 is preferably 10% or less.

As shown in FIG. 5, the high-strength fiber sheet 11 is woven with a plurality of first fiber bundles 11a and a plurality of second fiber bundles 11b orthogonal to the first fiber bundle 11a. The first fiber bundle 11a and the second fiber bundle 11b do not have to be orthogonal to each other. The fiber bundle is composed of high-strength fibers such as aramid fibers and carbon fibers. The fibers constituting the first fiber bundle 11a and the second fiber bundle 11b are made of the same material. Each fiber bundle has a structure in which a plurality of filaments (long fibers) are aligned. The tensile strength of the high-strength fiber sheet 11 in the orientation direction of the first fiber bundle 11a and the orientation direction of the second fiber bundle 11b is preferably 2000 N / mm2 or more, for example. When the fiber bundle is an aramid fiber, for example, it is 2060 N / mm2 or more, and when the fiber bundle is a carbon fiber, it is, for example, 2900 N / mm2 or more. The basis weight of the high-strength fiber sheet 11 is, for example, 90 to 870 g / m2 when the fiber bundle is aramid fiber, and 200 to 300 g / m2, for example, when the fiber bundle is carbon fiber. The thickness of the high-strength fiber sheet 11 is, for example, 0.03 to 0.24 mm when the fiber bundle is an aramid fiber, and 0.05 to 0.09 mm, for example, when the fiber bundle is a carbon fiber. The materials constituting the first fiber bundle 11a and the second fiber bundle 11b may be different.

In the high-strength fiber sheet 11, it is preferable that the first fiber bundle 11a and the second fiber bundle 11b are arranged so as to be inclined with respect to the belt circumferential direction. For example, in the high-strength fiber sheet 11, it is preferable that the first fiber bundle 11a and the second fiber bundle 11b are arranged so as to be inclined by 45 ° with respect to the belt circumferential direction. According to this configuration, since the fiber bundles of high-strength fibers are not arranged along the belt circumferential direction or the belt width direction, the friction transmission belt 2 has good flexibility. In the high-strength fiber sheet 11, the first fiber bundle 11a and the second fiber bundle 11b that are orthogonal to each other may be arranged so as to be along the belt circumferential direction and the belt width direction.

[Details of outer cover 8]
The outer cover 8 covers the circumference of the rubber layer 6 over the entire circumference in the belt circumferential direction. The outer cover 8 is preferably laminated twice. It is possible to more reliably prevent damage to the peripheral portion of the surface of the rubber layer 6 covered with the outer cover cloth 8, and in particular, more reliably to prevent damage to the peripheral portion of the end of the groove 10 of the rubber layer 6. Can be prevented. In addition, it is possible to more reliably prevent a decrease in the holding force due to wear on both side surfaces of the belt. The number of layers of the outer cover 8 may be 2 or more.

Examples of the fibers constituting the outer cover 8 include polyethylene terephthalate of polyalkylene allylate fibers such as polyethylene fibers and polypropylene fibers of polyolefin fibers, polyamide 6 fibers of polyamide fibers, polyamide 66 fibers, polyamide 46 fibers and aramid fibers. (PET) fiber, poly C2-4alkylene C6-14 allylate fiber such as polyethylene naphthalate (PEN) fiber, polyvinyl alcohol fiber, polyvinyl alcohol, ethylene-vinyl alcohol copolymer fiber, vinylon fiber, etc. Synthetic fibers such as polyparaphenylene benzobisoxazole (PBO) fibers, cellulose-based fibers, natural fibers such as wool, and inorganic fibers such as carbon fibers are widely used. The fibers constituting the outer cover 8 may be single yarns in which these fibers are used alone, or blended yarns in which two or more kinds are combined.

The outer cover cloth 8 may be a plain weave cloth in which the crossing angle between the warp and the weft is a right angle. Further, a plain weave cloth (wide-angle canvas) in which the crossing angle between the warp and the weft is larger than 90 ° and a wide angle of about 120 ° or less may be used. In addition, examples of the type of cloth of the outer cover cloth 8 include woven cloth woven in the form of twill weave, satin weave, knitted cloth (weft knitted cloth, warp knitted cloth), non-woven fabric and the like.

The density of the warp and weft of the outer cover 8 is, for example, 60 to 100 threads / 50 mm, preferably 70 to 90 threads / 50 mm, and more preferably about 75 to 85 threads / 50 mm. The thickness of the outer cover 8 is, for example, 0.4 to 2 mm, preferably 0.5 to 1.4 mm, and more preferably 0.6 to 1.2 mm.

[Action effect]
When the belt is bent forward, outward stress (extension stress) is generated on the outer peripheral side of the belt with respect to both side surfaces in the belt width direction. When the belt is reversely bent, inward stress (compressive stress) is generated on the outer peripheral side of the belt with respect to both side surfaces in the belt width direction. In the friction transmission belt 2 of the present embodiment, since the concave groove 10 extends along the peripheral direction of the belt on the outer peripheral surface 9 of the belt, in the state of being bent forward, the outer peripheral side of the belt is in the width direction of the belt. By deforming both sides inward with respect to both sides, the stress outward with respect to both sides is released, and the stress generated in the belt is relaxed. In the reverse bent state, on the outer peripheral side of the belt, both sides in the belt width direction are deformed outward with respect to both side surfaces to release inward stress with respect to both side surfaces, and the stress generated in the belt is relaxed. .. From the above, the concave groove 10 extends along the circumferential direction of the belt on the outer peripheral surface 9 of the belt, so that the bending stress generated in the friction transmission belt 2 when wound around the pulley in the power transmission system 1 is generated. It is alleviated, bending fatigue of the belt can be suppressed, and durability is improved. As a result, the temperature rise of the belt due to self-heating due to bending is suppressed, the deterioration of the rubber is prevented, and cracks are less likely to occur. Therefore, the friction transmission belt 2 is less likely to crack even under severe bending conditions and has excellent durability.

The friction transmission belt 2 of the present embodiment receives a strong impact because the core body layer 7 is composed of high-strength fibers and the core body layer 7 has a structure in which fiber bundles extending in two directions intersect. However, since the impact is dispersed, the strength is increased in both the belt width direction and the belt circumferential direction, and the impact resistance of the friction transmission belt 2 is improved. Further, the resistance of the friction transmission belt 2 to the lateral pressure received from the V groove 10 of the pulley is also improved. As a result, when the tension of the belt is increased in order to obtain a high transmission ability, even if the belt falls into the pulley, the belt is less likely to be significantly deformed on both sides, and the durability is also improved. Further, since the high-strength fiber sheet 11 is considerably thinner than the conventional core wire, a thin core body layer 7 can be obtained. As a result, the flexibility of the friction transmission belt 2 is improved.

(Modification example)
A modification of the present invention will be described below. (1) In the above embodiment, the cross-sectional shape of the concave groove 10 in the cross section of the friction transmission belt 2 including the belt width direction is semi-elliptical, but the cross-sectional shape of the groove 30a of the friction transmission belt 22a is , As shown in FIG. 6A, it may be circular. As shown in FIG. 6B, the cross-sectional shape of the groove 30b of the friction transmission belt 22b may be triangular. As shown in FIG. 6C, the cross-sectional shape of the groove 30c of the friction transmission belt 22c may be a quadrangle.

(2) In the above embodiment, the outer peripheral surface 9 of the friction transmission belt 2 has one concave groove 10 extending along the circumferential direction of the belt, but there may be a plurality of concave grooves 10.

(3) In the above embodiment, the outer cover 8 covers the circumference of the rubber layer 6 over the entire circumference in the belt circumferential direction, but from the viewpoint of protecting the grooves, the outer cover 8 is formed with grooves. Only the outer peripheral surface of the belt may be covered.

(4) In the above embodiment, as shown in FIG. 4, the core body layer 7 is separated from the bottom of the groove 10 and the inner peripheral surface 12 of the friction transmission belt 2 and is located at the center of the rubber layer 6. However, as shown in FIG. 7, the core body layer 37 may be located near the inner peripheral surface 33 of the friction transmission belt 32.

(5) As shown in FIG. 8, the friction transmission belt 42 may have a shape in which a plurality of V-belts are connected in the belt width direction. In the friction transmission belt 42 of this embodiment, each V-shaped protrusion 43 is endless, and the rubber layer 46 formed of the rubber composition and the core embedded in the rubber layer 46 along the circumferential direction of the belt. It includes a body layer 47 and an outer cover 48, and has a concave groove 50 along the peripheral direction of the belt on the outer peripheral surface 49. The plurality of V-shaped protrusions 43 are connected by a connecting portion 44 composed of a rubber layer 46 and an outer cover 48.

(6) In the above embodiment, as shown in FIG. 1, the friction transmission belt 2 is wound around the drive pulley 3, the driven pulley 4, and the tension pulley 5, but may be wound around a larger number of pulleys. At this time, the friction transmission belt may be used under severe bending conditions in which a state of being bent forward and a state of being bent backward are continuously repeated. Since a concave groove extends along the circumferential direction of the belt on the outer peripheral surface of the belt, it is used under severe bending conditions in which the belt is bent forward and backward continuously. However, bending fatigue of the belt is suppressed and cracks are unlikely to occur.

The friction transmission belts of Examples 1-1 to 3-15 and Comparative Examples 1 to 3 shown in Tables 5 to 14 were produced in which the dimensions of the friction transmission belts shown in FIG. 4 were variously changed. Then, the durability of each friction transmission belt produced was evaluated by applying a load equivalent to that of an actual machine in a two-axis running test. Specifically, each of the produced friction transmission belts is wound between the drive pulley (Dr) and the driven pulley (Dn), and is run with a load equivalent to that of the actual machine, resulting in cracks in the rubber layer. The time until occurrence was measured, and durability evaluation (judgment of life) was performed.

The configurations of the friction transmission belts of Examples 1-1 to 3-15 (with concave grooves) and Comparative Examples 1 to 3 (without concave grooves) will be described.

The rubber composition 1 shown in Table 1 is used as the rubber layer arranged between the core body layer and the outer peripheral surface of each friction transmission belt, and the rubber arranged between the core body layer and the inner peripheral surface is used. As the layer (compressed rubber layer), the rubber composition 1 shown in Table 1 was used.

As the outer cover, a cotton woven fabric (plain weave, fineness composed of 10th warp and 10th weft, warp and weft density of 35 yarns / 50 mm, basis weight 320 g / m ² ) was used. The number of layers of the outer cover (number of coatings) was set to 2 times. Further, the laminated outer coat was subjected to a friction treatment using the rubber composition 2 shown in Table 1.

As the core layer, a plurality of aramid sheets (AK-50 / 50) (high-strength fiber sheets) shown in Table 2 were laminated. In the core layer of the friction transmission belt of HI2800 of Examples 1-1 to 1-17 and Comparative Example 1, three aramid sheets are laminated. Further, four aramid sheets are laminated on the core layer of the friction transmission belt of HK3200 of Examples 2-1 to 2-15 and Comparative Example 2. Further, five aramid sheets are laminated on the core layer of the friction transmission belt of HM4000 of Examples 3-1 to 3-15 and Comparative Example 3.

In Examples 1-1 to 1-17 and Comparative Example 1, the friction of the dimensions (width, thickness) of the HI type HI2800 of the V-belt ASABE standard for large agricultural machinery (American Society of Agricultural Engineering) shown in Table 3. A transmission belt was used.
In Examples 2-1 to 2-15 and Comparative Example 2, the friction of the dimensions (width, thickness) of the HK type HK3200 of the V-belt ASABE standard for large agricultural machinery (American Society of Agricultural Engineering) shown in Table 3. A transmission belt was used.
In Examples 3-1 to 3-15 and Comparative Example 3, the friction of the dimensions (width, thickness) of the HM type HM4000 of the V-belt ASABE standard for large agricultural machinery (American Society of Agricultural Engineering) shown in Table 3. A transmission belt was used.

Further, the friction transmission belts of HI2800 of Examples 1-1 to 1-17 and Comparative Example 1, the friction transmission belts of HK3200 of Examples 2-1 to 2-15 and Comparative Example 2, and Examples. Table 4 shows the dimensions and running conditions of the drive pulley (Dr) and driven pulley (Dn) used in the biaxial running test for the friction transmission belt of HM4000 of Examples 3-15 and Comparative Example 3 from 3-1 to 3. show.

Tables 5 to 14 show the results and durability evaluations of the two-axis running test for each of the produced friction transmission belts. Tables 5 to 8 show the results and durability evaluations of the two-axis running test for the friction transmission belts of HI2800 of Examples 1-1 to 1-17 and Comparative Example 1. Tables 9 to 11 show the results and durability evaluations of the two-axis running test for the friction transmission belts of HK3200 of Examples 2-1 to 2-15 and Comparative Example 2. Tables 12 to 14 show the results and durability evaluations of the two-axis running test for the friction transmission belts of HM4000 of Examples 3-1 to 3-15 and Comparative Example 3. As for the durability evaluation (judgment of life), as a result of the two-axis running test, if the time until the cracks of the rubber layer occur is 220 hours or more, it is judged as "◎" and 180 hours or more and 220 hours. If it was less than 180 hours, it was judged as "◯", and if it was less than 180 hours, it was judged as "x".

(HI2800: W1 / W2 = 70%: When the groove depth (T1) is variable)
In Table 5, with respect to the friction transmission belt of HI2800, the groove depth (T1) was varied by keeping the position of the core layer in the thickness direction constant under the condition of W1 / W2 = 70%. The results of performing a two-axis running test on each friction transmission belt according to Examples 1 to 5 and Comparative Example 1 and the durability evaluation thereof are described.

(HI2800: W1 / W2 = 50%: When the groove depth (T1) is variable)
In Table 6, with respect to the friction transmission belt of HI2800, the groove depth (T1) was varied by keeping the position of the core layer in the thickness direction constant under the condition of W1 / W2 = 50%. The results of the two-axis running test and the durability evaluation thereof are described for each friction transmission belt according to 6 to 1-10.

(HI2800: W1 / W2 = 60%: When the position of the core layer in the thickness direction is variable)
In Table 7, with respect to the friction transmission belt of HI2800, the position of the core layer in the thickness direction was varied by keeping the groove depth (T1) constant under the condition of W1 / W2 = 60%. The results of the two-axis running test and the durability evaluation thereof are described for each friction transmission belt according to 11 to 1-15.

(HI2800: When the value of W1 / W2 is variable (when the value of W1 is variable))
In Table 8, regarding the friction transmission belt of HI2800, the belt width W2 was kept constant, the groove width W1 was variable, and the value of W1 / W2 was variable. Example 1-16 (W1 / W2 = 40). %), Each friction transmission belt according to Example 1-8 (W1 / W2 = 50%), Example 1-3 (W1 / W2 = 70%), and Example 1-17 (W1 / W2 = 80%). The results of the two-axis running test and the durability evaluation thereof are described.

(HK3200: W1 / W2 = 70%: When the groove depth (T1) is variable)
In Table 9, with respect to the friction transmission belt of HK3200, the groove depth (T1) was varied by keeping the position of the core layer in the thickness direction constant under the condition of W1 / W2 = 70%. The results of performing a two-axis running test on each friction transmission belt according to Examples 1 to 2-5 and Comparative Example 2 and the durability evaluation thereof are described.

(HK3200: W1 / W2 = 50%: When the groove depth (T1) is variable)
In Table 10, with respect to the friction transmission belt of HK3200, the groove depth (T1) was varied by keeping the position of the core layer in the thickness direction constant under the condition of W1 / W2 = 50%. The results of the two-axis running test and the durability evaluation thereof are described for each friction transmission belt according to Examples 6 to 2-10.

(HK3200: W1 / W2 = 60%: When the position of the core layer in the thickness direction is variable)
In Table 11, with respect to the friction transmission belt of HK3200, the position of the core layer in the thickness direction was varied by keeping the groove depth (T1) constant under the condition of W1 / W2 = 60%. The results of the two-axis running test and the durability evaluation thereof are described for each friction transmission belt according to 11 to 2-15.

(HM4000: W1 / W2 = 70%: When the groove depth (T1) is variable)
In Table 12, with respect to the friction transmission belt of HM4000, the groove depth (T1) was varied by keeping the position of the core layer in the thickness direction constant under the condition of W1 / W2 = 70%. The results of performing a two-axis running test on each friction transmission belt according to Examples 1 to 3-5 and Comparative Example 3 and the durability evaluation thereof are described.

(HM4000: W1 / W2 = 50%: When the groove depth (T1) is variable)
In Table 13, with respect to the friction transmission belt of HM4000, the groove depth (T1) was varied by keeping the position of the core layer in the thickness direction constant under the condition of W1 / W2 = 50%. The results of the two-axis running test and the durability evaluation thereof are described for each friction transmission belt according to Examples 6 to 3-10.

(HM4000: W1 / W2 = 60%: When the position of the core layer in the thickness direction is variable)
In Table 14, with respect to the friction transmission belt of HM4000, the position of the core layer in the thickness direction was varied by keeping the groove depth (T1) constant under the condition of W1 / W2 = 60%. The results of the two-axis running test and the durability evaluation thereof are described for each friction transmission belt according to 11 to 3-15.

From the results of the above-mentioned two-axis running test, by providing a concave groove on the surface of the friction transmission belt on the outer peripheral side of the belt (Examples 1-1 to 3-15), a friction transmission belt without a groove (comparison). Compared with Examples 1 to 3), bending fatigue can be suppressed and durability (particularly, durability of the rubber layer (compressed rubber layer) arranged between the core body layer and the inner peripheral surface) can be improved. Was confirmed.

Further, as shown in Table 8, Example 1-16 (W1 / W2 = 40%) having a groove width W1 smaller than that of Example 1-8 (W1 / W2 = 50%) is a two-axis running test. As a result, cracks occurred earlier than in Examples 1-8 due to insufficient flexibility (determination "○"). Further, in Example 1-17 (W1 / W2 = 80%) in which the groove width W1 is larger than that of Example 1-3 (W1 / W2 = 70%), as a result of the biaxial running test, the vicinity of the groove at the time of bending is obtained. Since the continuous deformation (deformation that expands in the belt width direction or returns to the original shape) is large, cracks occur earlier than in Examples 1-3 (determination “◯”). As a result, it was confirmed that the durability of the friction transmission belt can be further improved by setting "W1 (groove width) / W2 (belt width) = 50% to 70%".

Furthermore, it was confirmed that the durability of the friction transmission belt can be further improved by setting "T1 (groove depth) / T2 (belt thickness) = 5% to 20%" (implementation). See Examples 1-1-1 to Example 1-10, Examples 2-1 to 2-10, and Examples 3-1 to 3-10).

1 Power transmission system 2 Friction transmission belt 3 Drive pulley 4 Driven pulley 5 Tension pulley 6 Rubber layer 7 Core layer 8 Outer cloth 9 Outer surface 10 Groove 11 High-strength fiber sheet 12 Inner peripheral surface

Claims (6)

An endless friction transmission belt with a rubber layer made of a rubber composition,
Includes a core layer embedded in the rubber layer along the belt circumferential direction,
The outer peripheral surface of the friction transmission belt, have a concave groove along the circumferential direction of the belt,
A friction transmission belt, characterized in that the shape of the groove in a cross section including the belt width direction of the friction transmission belt is semicircular or semi-elliptical. The friction transmission belt according to claim 1 , wherein the width of the groove is 50% to 70% of the belt width. The friction transmission belt according to claim 1 or 2 , wherein the depth of the groove is 5% to 20% of the belt thickness. The friction transmission belt according to any one of claims 1 to 3 , wherein the core body layer is composed of a high-strength fiber sheet having a structure in which fiber bundles extending in two directions intersect. The friction transmission belt according to any one of claims 1 to 4 , wherein at least the outer peripheral surface is covered with an outer cover cloth. The belt width of the friction transmission belt is 24.4 mm to 50.8 mm.
The friction transmission belt according to any one of claims 1 to 5 , wherein the belt thickness of the friction transmission belt is 12.7 mm to 22.2 mm.

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