JP6868575B2 - Manufacturing method of double-sided transmission belt - Google Patents

Description

The present invention relates to a double-sided transmission belt for double-sided transmission having a V side surface on the inner peripheral side and a V side surface on the outer peripheral side, and a method for manufacturing the same.

This double-sided transmission belt is used for applications that require double-sided drive or multi-axis drive due to space problems. The double-sided transmission belt used for double-sided drive and multi-axis drive has a shape in which two V-belts are combined on the back surface, and is also called a double V-belt or a hexagonal belt.

This hexagonal belt is thick because it has a shape in which two V-belts are combined on the back surface. Due to its thickness, flexibility becomes a problem. Therefore, it is known that a cog portion having a U-shaped notch is provided in the belt circumferential direction of each V-belt on the inner and outer peripheral sides to enhance the flexibility.

For example, in Patent Document 1, in a low-edge V-belt for double-sided transmission, a lower cog is formed on the inner peripheral side of the belt body at a constant pitch along the length direction, and the inner peripheral side of the belt body is covered with an inner reinforcing cloth. Then, an upper cog is formed on the outer peripheral side of the belt body at a constant pitch along the length direction, the outer peripheral side of the belt body is covered with an outer reinforcing cloth, and an adhesive rubber layer is placed between the lower cog and the upper cog. What to do is known. Here, the low-edge V-belt refers to a rubber layer having an exposed friction transmission surface.

Further, Patent Document 2 describes a belt that enables multi-axis transmission with a small number of belts in a device having parts that require different transmission characteristics, and has an inner peripheral side portion with a lower cog and an outer peripheral portion with an upper cog. A transmission belt for double-sided transmission having a side portion is known. The friction transmission surface of the inner peripheral side portion and the friction transmission surface of the outer peripheral side portion have different friction coefficients. For example, by using a wrapped V-belt for the inner peripheral side portion and a low-edge V-belt for the outer peripheral side portion, the friction coefficients are made different from each other. Here, the wrapped V-belt refers to a friction transmission surface (V-shaped side surface) covered with an outer cover.

WO2013-06924A Japanese Unexamined Patent Publication No. 2016-200231

However, although the transmission belt for double-sided transmission in Patent Documents 1 and 2 is provided with a cog portion, the size is still thick when viewed from the friction transmission surface. Therefore, there is a problem that cracks (cracks) in the compressed rubber and core wire peeling due to bending fatigue and bending heat may occur at an early stage as the diameter of the pulley becomes smaller due to the compactness of the device and the distance between the shafts is shortened. There was a point.

Therefore, an object of the present invention is to provide a double-sided transmission belt for double-sided transmission suitable for applications requiring a higher degree of flexibility and a method for manufacturing the same.

Means for Solving Problems and Effects of Invention

The double-sided transmission belt of the present invention has a hexagonal shape with a flat cross section, and has a belt base having a continuous outer peripheral side transmission surface and a continuous inner peripheral side transmission surface formed on both side surfaces.
An outer peripheral protrusion that is provided on the outer peripheral surface of the belt base at predetermined intervals and forms an intermittent transmission surface that follows the continuous outer peripheral transmission surface.
An inner peripheral projection portion provided on the inner peripheral surface of the belt base at predetermined intervals and forming an intermittent transmission surface following the continuous inner peripheral side transmission surface is provided.
The belt base portion is characterized by having an easily bendable portion in which neither the outer peripheral side protrusion portion nor the inner peripheral side protrusion portion is provided.

The length of the easily bendable portion is appropriately 0.5 to 14 times the width dimension of the outer peripheral side protrusion portion or the inner peripheral side protrusion portion, whichever is larger. This value is selected from the viewpoint of ensuring the required flexibility and obtaining the required transmission performance. In particular, it is sufficient that the transmission surface has an area sufficient to obtain the minimum necessary transmission characteristics.

As for the degree of flatness of the belt base, the belt base width W / belt base thickness T1 is appropriately 4 to 7. It is selected in terms of the required flexibility.

Further, it is preferable that the outer peripheral side protrusions and the inner peripheral side protrusions have the same shape and size and are arranged alternately in a staggered pattern or are arranged so as to coincide with each other on the inner and outer circumferences. ..

According to this configuration, the belt base has a straight flexible portion, so that the flexibility is excellent. In addition, since the belt base is flat, the thickness can be reduced, so that it is excellent in flexibility and can withstand running conditions of small pulleys and multiple axes. Further, since the belt base is flat, it is excellent in heat dissipation, it is possible to suppress an increase in the belt temperature due to running, and it is possible to prevent thermal deterioration of the belt.

In the present invention, the outer peripheral side protrusion and the inner peripheral side protrusion are preferably molded bodies including a high-strength fiber sheet having a high-strength fiber bundle oriented in the width direction of the belt base.

According to this configuration, since the belt base is provided with a flexible portion, the lateral pressure resistance is inferior, but the portion is a high-strength fiber bundle oriented in the belt width direction of the outer peripheral side protrusion and the inner peripheral side protrusion. Can be reinforced with. That is, since it is a molded product containing a high-strength fiber sheet having a high-strength fiber bundle oriented in the width direction of the belt base, it is excellent in lateral pressure resistance. Therefore, even if it is used with high tension in order to obtain high transmission ability, bending deformation is reduced and a large shear stress does not occur. As a result, interfacial delamination due to shear stress is unlikely to occur. Further, since it is a protrusion containing a high-strength fiber sheet, it has excellent wear resistance. Therefore, it is possible to prevent a decrease in tension due to thinning of the belt.

The double-sided transmission belt of the present invention has a hexagonal shape with a flat cross section, and has a belt base having a continuous outer peripheral side transmission surface and a continuous inner peripheral side transmission surface formed on both side surfaces.
An outer peripheral protrusion that is provided on the outer peripheral surface of the belt base at predetermined intervals and forms an intermittent transmission surface that follows the continuous outer peripheral transmission surface.
An inner peripheral projection portion provided on the inner peripheral surface of the belt base at predetermined intervals and forming an intermittent transmission surface following the continuous inner peripheral side transmission surface is provided.
The belt base has an easily bendable portion in which neither the outer peripheral side protrusion nor the inner peripheral side protrusion is provided.
The outer peripheral side protrusion and the inner peripheral side protrusion are a method for manufacturing a double-sided transmission belt, which is a molded body including a high-strength fiber sheet having a high-strength fiber bundle oriented in the width direction of the belt base. ,
A process of arranging high-strength fiber sheets that have been subjected to adhesive treatment on the inner and outer peripheral surfaces of an unvulcanized flat belt by wrapping them around to make an unvulcanized product.
A process in which the unvulcanized product is sandwiched between molded presses and integrally vulcanized and molded at the same time to obtain a vulcanized molded product.
It is characterized by including a step of right-angle cutting in the width direction of the vulcanized molded product and further bias cutting.

According to this configuration, the inner and outer peripheral protrusions and the easily bendable portion can be distinguished and reliably molded. Further, the high-strength fiber bundle can be reliably arranged in the width direction of the inner and outer peripheral protrusions.

In the present invention, the high-strength fiber sheet is preferably a one-way sheet.

According to this configuration, the workability when winding the high-strength fiber sheet round and round is excellent.

It is a perspective view of the double-sided transmission belt of this invention. It is a front view of a double-sided transmission belt. It is a side view of a double-sided transmission belt. It is a side view of the double-sided transmission belt of a modification. It is a conceptual diagram for demonstrating the manufacturing procedure of a double-sided transmission belt. It is a conceptual diagram for demonstrating the manufacturing procedure of a double-sided transmission belt. It is a conceptual diagram for demonstrating the manufacturing procedure of a double-sided transmission belt. It is a perspective view of the double-sided transmission belt of a modification. It is a perspective view of the double-sided transmission belt of a modification. It is a perspective view of the double-sided transmission belt which concerns on embodiment. It is a perspective view of the double-sided transmission belt which concerns on a comparative example. It is a layout figure which shows the 2 motor multi-axis reverse bend running test apparatus used for evaluation.

Next, an embodiment of the present invention will be described.
The double-sided transmission belt 1 of the present embodiment is used, for example, in an application of agricultural machinery such as a textile machine and a rubbing machine, which require double-sided drive and multi-axis transmission due to space problems and the like. The double-sided transmission belt of the present invention is also used in a roller drive application in a roller type transfer device used in a distribution center or the like.

The double-sided transmission belt 1 is annular and is used by being wound around at least two pulleys (drive pulley and driven pulley). In the following description, the belt circumferential direction, the belt width direction, and the belt thickness direction are the directions shown in FIG. The outer peripheral side of the belt and the inner peripheral side of the belt refer to the upper side and the lower side of the belt base 2 in FIG.

The double-sided transmission belt 1 includes a belt base portion 2, an outer peripheral side protrusion 3, and an inner peripheral side protrusion 4.
The belt base 2 is formed by providing a core 6 on the center line in the thickness direction of the rubber layer 5. The core body 6 is formed by spirally winding a core wire in the circumferential direction to form a tensile strength body.

The belt base 2 has a hexagonal shape having a flat cross section orthogonal to the belt circumferential direction. On both side surfaces thereof, an inverted V-shaped continuous outer peripheral side transmission surface 7 and 7 and a V-shaped continuous inner peripheral side transmission surface 8 and 8 are formed. There is. The continuous outer peripheral side transmission surfaces 7 and 7 are sandwiched between V-grooves of a pulley (not shown), and power is transmitted by frictional force due to contact. The continuous inner peripheral side transmission surfaces 8 and 8 are sandwiched between V-grooves of other pulleys (not shown), and power is transmitted by frictional force due to contact.

The maximum length W of the belt base 2 in the belt width direction is, for example, 13 to 22 mm. The belt thickness T1 of the belt base 2 is, for example, 2 to 5 mm. The degree of flatness indicated by W / T1 is preferably about 4 to 7.

The belt base portion 2 has an easily bendable portion 9 in which neither the outer peripheral side protrusion 3 nor the inner peripheral side protrusion 4 is provided. The easily bendable portion 9 is a portion composed of only the flat belt base portion 2 and has high flexibility. Further, since the belt base 2 is flat, it is excellent in heat dissipation. The length L of the easily bendable portion 9 is preferably about 0.5 to 14 times the width dimension W1 of the outer peripheral side protrusion 3 and the inner peripheral side protrusion 4, whichever is larger.

The rubber layer constituting the belt base 2 is formed, for example, by sandwiching the inside and outside of the first rubber layer in which the core body 6 is embedded between the second rubber layer and the third rubber layer. These first to third rubber layers are configured to contain a rubber composition. The rubber composition constituting the first rubber layer has higher adhesiveness to the core body 6 than the rubber composition constituting the second and third rubber layers. The rubber composition constituting the second rubber layer and the rubber composition constituting the third rubber layer may be the same or different.

As the rubber component of the rubber composition, vulcanized or crosslinkable rubber is used. Specifically, for example, diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, hydride nitrile rubber, etc.), ethylene-α-olefin elastomer, chlorosulphonized polyethylene rubber, etc. , Alkylated chlorosulphonized polyethylene rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, fluorinated rubber and the like. These rubber components can be used alone or in combination of two or more.

Vulcanization agents or cross-linking agents, co-cross-linking agents, vulcanization aids, vulcanization accelerators, vulcanization retarders, metal oxides (zinc oxide, magnesium oxide, calcium oxide, etc.) may be added to the rubber composition, if necessary. Barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), enhancer (carbon black, silicon oxide such as hydrous silica, etc.), short fibers, filler (clay, calcium carbonate, talc, mica, etc.), softening Agents (oils such as paraffin oil and naphthenic oil), processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, etc.), antioxidants (antioxidants, heat antiaging agents, bending Crack inhibitor, ozone deterioration inhibitor, etc.), colorant, tackifier, plasticizer, coupling agent (silane coupling agent, etc.), stabilizer (ultraviolet absorber, heat stabilizer, etc.), flame retardant, antistatic Agents and the like may be blended. The metal oxide may be blended as a cross-linking agent.

The rubber composition constituting the second rubber layer and the third rubber layer may contain short fibers. The rubber composition constituting the first rubber layer does not contain short fibers.

The core wires constituting the core body 6 extend in the circumferential direction of the belt and are embedded at regular intervals in the width direction of the belt. The core wire consists of a twisted cord (various twists, single twists, rank twists, etc.) using multifilament yarns. The material of the core wire is, for example, a synthetic fiber such as an aramid fiber or an inorganic fiber such as a carbon fiber. The core wire may be subjected to an adhesive treatment with an RFL liquid or the like for the purpose of enhancing the adhesiveness with the adhesive rubber layer 7.

As shown in FIG. 3, the outer peripheral side projection portion 3 is provided on the outer peripheral side of the belt base portion 2 at a predetermined pitch P. The inner peripheral protrusions 4 are separated from the outer peripheral protrusions 3 and P / 2 on the inner peripheral side of the belt base 2 in the belt circumferential direction, and are located exactly in the center of the outer peripheral protrusions 3 at a predetermined pitch P. It is provided.

The outer peripheral side protrusion 3 and the inner peripheral side protrusion 4 have the same shape, and are trapezoidal (V-shaped) when viewed in the circumferential cross section. The trapezoidal width W1 of the protrusions 3 and 4 is, for example, 4 to 20 mm. The trapezoidal height T2 of the protrusions 3 and 4 is, for example, 4 to 6 mm.

As shown in FIG. 2, the outer peripheral side protrusions 3 are formed with transmission surfaces 11 and 11 following the outer peripheral side transmission surfaces 7 and 7 of the belt base 2 on both side surfaces thereof. The transmission surfaces 11 and 11 appear intermittently at predetermined pitch P in the belt circumferential direction. The inner peripheral side protrusions 4 are formed with transmission surfaces 12 and 12 following the inner peripheral side transmission surfaces 8 and 8 of the belt base 2 on both side surfaces thereof. The transmission surfaces 12 and 12 appear intermittently at predetermined pitch P in the belt circumferential direction.
When the state in which the protrusions 3 and 4 are provided on the belt base 2 is viewed from the front in the circumferential direction of the belt, it has a so-called hexagonal belt shape. Looking at the double-sided transmission belt 1 as a whole, its thickness T is, for example, 10 to 17 mm. On the other hand, the maximum length W of the belt base 2 in the belt width direction is, for example, 13 to 22 mm as described above.

Since the transmission surfaces 11 and 11 of the outer peripheral side protrusion 3 and the transmission surfaces 12 and 12 of the inner peripheral side protrusion 4 appear intermittently in the belt circumferential direction, the area of the transmission surface is larger than that of a normal hexagonal belt. Decrease. However, it suffices if the minimum necessary transmission performance can be secured.

The outer peripheral side protrusion 3 and the inner peripheral side protrusion 4 not only secure the required area of the transmission surface, but also reinforce the lateral pressure resistance of the flat hexagonal belt base 2 in the belt width direction. It is provided in. Therefore, a molded product containing a high-strength fiber sheet having a high-strength fiber bundle oriented in the width direction of the belt base 2 is preferable.
As shown in FIG. 1, the ends 15 of the high-strength fiber bundle are exposed on both transmission surfaces 11 and 11 of the outer peripheral side protrusion 3 and both transmission surfaces 12 and 12 of the inner peripheral side protrusion 4.

The high-strength fiber sheet used here is a fiber sheet used for repairing / reinforcing a concrete structure, for example, as described in Japanese Patent Application Laid-Open No. 57-52221 and JP-A-10-102364. It is positioned as a high-strength fiber sheet made of hard material.
This high-strength fiber sheet includes a one-way sheet in which high-strength fiber bundles are knitted in one direction (warp direction or weft direction) or high-strength fiber bundles are bonded and arranged with a binder or the like, and two high-strength fiber bundles. There are two-way sheets that are woven or woven so as to intersect in the direction (warp direction and weft direction), and any of them can be used.

The high-strength fiber bundle is composed of, for example, aramid fiber, carbon fiber, or a combination thereof. As the high-strength fiber sheet using these high-strength fiber bundles, those having the following parameters are preferably used. (For one-way seats)
Basis weight of the high-strength fiber sheet, if composed of aramid fibers is 230~830g / m ^2, when composed of carbon fibers, 200~450g / m ^2.
Tensile strength of the high strength fiber sheet, if composed of aramid fibers, and at 2060N / mm ² or more, when composed of carbon fibers is 2900N / mm ² or more.
The thickness of the high-strength fiber sheet is 0.16 to 0.60 mm when composed of aramid fibers and 0.11 to 0.35 mm when composed of carbon fibers. (For two-way seats)
The grain size of the high-strength fiber sheet is 90 to 870 g / m ² when it is composed of aramid fibers, and 200 to 300 g / m ^{2 when} it is composed of carbon fibers.
Tensile strength of the high strength fiber sheet, if composed of aramid fibers, and at 2060N / mm ² or more, when composed of carbon fibers is 2900N / mm ² or more.
The thickness of the high-strength fiber sheet is 0.03 to 0.24 mm when composed of aramid fibers, and 0.05 to 0.09 mm when composed of carbon fibers.

The orientation of the fibers at the protrusions 3 and 4 is arranged so that the orientation direction of the high-strength fiber bundle of the high-strength fiber sheet is the belt width direction. Therefore, the protrusions 3 and 4 are integrally molded with the belt base 2 as a molded body in which a high-strength fiber sheet is wound around and vulcanized to form a predetermined shape.

When used for the protrusions 3 and 4, the orientation of the high-strength fiber bundle is required in the belt width direction, and the orientation in the longitudinal direction is not essential. Either a one-way sheet or a two-way sheet may be used as long as the high-strength fiber bundle can be oriented in the belt width direction. However, considering the workability of making a round and round roll, the one-way sheet is advantageous in that it is easier to roll.

The high-strength fiber sheet is used after being subjected to an adhesive treatment. At this time, the high-strength fiber sheet may be used alone, or may be used in a state where a known resin component (binder) such as an RFL liquid or an impregnated resin is appropriately selected and subjected to an adhesive treatment. When a high-strength fiber sheet is used for the protrusions 3 and 4, an adhesive treatment (for example, immersion treatment with rubber glue, sheet-like rubber) in which an adhesive component containing a rubber composition is attached to the single body or the adhesive-treated sheet. It may be laminated) and used as a fiber sheet with rubber.
The above-mentioned adhesive treatment enhances the moldability of the protrusions 3 and 4 including the high-strength fiber sheet, and also enhances the adhesiveness of the protrusions 3 and 4 to the belt base 2.

Here, the RFL solution is a mixture of an initial condensate of resorcin and formalin into latex, and the latex used here includes a styrene-butadiene-pyridine ternary copolymer, hydrogenated nitrile rubber, and chlorosulfonated. Latex such as polyethylene and epichlorohydrin.
The resin solution used for the impregnated resin treatment is, for example, an isocyanate solution or an epoxy solution. After the impregnated resin treatment, an adhesion treatment using an RFL liquid treatment may be performed.
In the adhesive treatment using rubber glue, an unvulcanized rubber composition is dissolved in a solvent to form a rubber paste, which is applied to the surface of a high-strength fiber sheet, and then the solvent is evaporated to form a high-strength fiber sheet. A film of an unvulcanized rubber composition is formed on the surface of the rubber composition. After the adhesion treatment using the RFL liquid, the rubber glue treatment may be performed.

Here, the rubber composition used for the above-mentioned bonding treatment is preferably the same as the rubber composition used for the belt base 2.

The double-sided transmission belt 1 of the above-described embodiment has the following effects.
Even if it is used with high tension to obtain high transmission ability, buckling deformation is small because it has excellent lateral pressure resistance, and a large shear stress does not occur. As a result, interfacial delamination due to shear stress is unlikely to occur.
The protrusions 3 and 4 around which the high-strength fiber sheet is wound have excellent wear resistance due to the effect of the material, and it is possible to prevent a decrease in tension due to thinning of the belt.
Since the protrusions 3 and 4 around which the high-strength fiber sheet is wound are attached at equal intervals and the easily bendable portion 9 is provided between the pitches, the flexibility is good, and the flexibility is excellent even when compared with the thick hexagonal belt. It has a structure.
The structure of the belt base 2 is excellent in running stability because the core wire line is not easily disturbed due to the production method. In addition, since it is small in thickness, it has excellent flexibility and can sufficiently withstand running conditions of small pulleys and multiple shafts.
The belt base 2 has a shape having a large heat dissipation area in addition to having good flexibility. Therefore, it is possible to suppress an increase in the belt temperature due to running, and it is possible to prevent thermal deterioration of the belt.

Next, the manufacturing procedure of the double-sided transmission belt 1 will be described with reference to FIGS. 5 to 7.
First, as shown in FIG. 5, an unvulcanized flat belt 21 and a rubber-attached fiber sheet 22 in which an adhesive-treated high-strength fiber sheet is wound around are molded.
The unvulcanized flat belt 21 is formed by sandwiching the inside and outside of the first rubber layer in which the core body is embedded between the second rubber layer and the third rubber layer.
The rubber-attached fiber sheet 22 is obtained by winding a high-strength fiber sheet 22b to which an adhesive component 22a such as a rubber component or a resin component is attached by the above-mentioned adhesive treatment, and orienting the high-strength fiber bundle in the longitudinal direction. ..
Next, the unvulcanized product 23 is prepared by arranging the rubberized fiber sheets 22 on the upper and lower surfaces of the unvulcanized flat belt 21 at predetermined intervals.

Next, as shown in FIG. 6, the unvulcanized product 23 is arranged between the upper press machine 24 having the V groove 24a and the upper press machine 25 having the V groove 25a.
By pressurizing and heating with the press plates 24 and 25, the protrusions are molded and the belt base 2 and the protrusions 3 and 4 are integrally vulcanized to obtain a vulcanized molded product 26.

Next, as shown in FIG. 7, in the cut cross section in the belt width direction, first, the cuts 27 and 27 are made at right angles to the predetermined width of the belt. Next, the bias cuts 28 and 28 are separately performed on the inner and outer peripheral sides so as to form a hexagonal shape.

According to the above manufacturing method, the inner and outer peripheral protrusions 3 and 4 and the easily bendable portion 9 can be distinguished and reliably molded. Further, the high-strength fiber bundle can be reliably arranged in the width direction of the inner and outer peripheral protrusions 3 and 4. Further, when a unidirectional sheet is used as the high-strength fiber sheet, it can be seen that the workability of winding around is excellent.

Next, a modified example of the present embodiment will be described.
FIG. 4 shows a double-sided transmission belt 101 in which the inner and outer peripheral protrusions 3 and 4 are arranged so as to coincide with the belt thickness direction. The area of the transmission surface is the same as that of the double-sided transmission belt 1 in FIG. 3, but the length of the easily bendable portion 109 is longer than that in FIG. 3, and the flexibility is more excellent.
As described above, those having the same shape and size of the inner and outer protrusions 3 and 4 and arranged alternately in a staggered pattern or uniformly arranged on the inner and outer circumferences are the easily bent portions 9, 109 appears periodically, which is advantageous in terms of stable running.

However, the shapes and sizes of the inner and outer protrusions 3 and 4 may be different, such as when the required transmission characteristics change on the inner and outer circumferences. Further, the arrangement pitches of the inner and outer protrusions 3 and 4 may be different. For example, the outer peripheral side protrusions 3 may be arranged at a pitch that is half that of the inner peripheral side protrusions 4. As long as the necessary flexible portions appear periodically, the arrangement of the internal and external protrusions 3 and 4 can be freely arranged as long as the transmission performance is satisfied.

FIG. 8 shows a double-sided transmission belt 301 in which the shape of the circumferential cross section of the internal / external protrusions 303 and 304 is a quadrangle.
FIG. 9 shows a double-sided transmission belt 401 in which the shape of the circumferential cross section of the internal / external protrusions 403 and 404 is a semicircle.
According to the manufacturing methods of FIGS. 5 to 7, the shape of the inner and outer protrusions is not limited to the V shape of FIG. 1, and can be various shapes.
Further, an outer cover different from the high-strength fiber sheet may be provided on the outer periphery of the inner and outer protrusions. According to the manufacturing methods of FIGS. 5 to 7, an outer cover can be easily provided on the inner and outer circumferences of the double-sided transmission belt, and the inner and outer protrusions and / and the inner and outer peripheral surfaces of the belt base can be reinforced.

Although the embodiments of the invention have been described above with reference to the drawings, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is indicated not only by the above-described embodiments but also by the scope of claims, and further includes all modifications within the meaning and scope equivalent to the scope of claims.

Next, specific examples of the present invention will be described.
Double-sided transmission belts as shown in Examples 1 to 3 and the comparison row shown below were formed and subjected to an evaluation test.

The double-sided transmission belts of Examples 1 to 3 have a belt type conforming to the BB type, and are formed with the dimensions shown in FIG. In particular, an easily bendable portion 9 having L = 20 mm is provided between the outer peripheral side protrusion 3 and the inner peripheral side protrusion 4.

The belt bases 2 of Examples 1 to 3 are formed by embedding a core body 6 on the center line in the thickness direction of the rubber layer 5.
The adhesive rubber layer constituting the belt base 2 is composed of the rubber composition B shown in Table 1 below.
A twisted cord of polyester fiber having an average wire diameter of 1.985 mm is used for the core wire constituting the core body 6.

Example 1 uses the aramid fiber sheet 1 (unidirectional sheet) shown in Table 2 below for the outer peripheral side protrusion 3 and the inner peripheral side protrusion 4, and the aramid fiber sheet 2 (1) shown in Table 2 below is used. The one using the directional sheet) was designated as Example 2, and the one using the carbon fiber sheet 1 (unidirectional sheet) shown in Table 2 below was designated as Example 3.
The fiber bundles of these high-strength fiber sheets are arranged in a direction orthogonal to the longitudinal direction of the belt base 2.

The high-strength fiber sheet constituting the outer peripheral side protrusion 3 and the inner peripheral side protrusion 4 is formed by subjecting an adhesive treatment of soaking and application of liquid rubber.
For the soaking, liquid rubber for soaking in which the rubber paste is adjusted with 100 parts by mass of "rubber composition C" and 1100 parts by mass of "toluene" shown in Table 1 is used. A cloth is passed through the immersion tank containing the rubber glue, and the cloth is passed between the two rolls to remove excess rubber glue, and the rubber glue is allowed to penetrate into the fiber. The number of times of this soaking process is two on the front and back.
The liquid rubber is applied by using a liquid rubber in which rubber glue is adjusted with 100 parts by mass of "rubber composition C" and 400 parts by mass of "toluene" shown in Table 1, and unvulcanized rubber is applied to the sheet after the soaking treatment. A film of the composition was formed. After applying this liquid rubber, the solvent is evaporated to form an unvulcanized rubber film on the surface of the fabric. The coated surface of the liquid rubber and the number of times are once on one side.

The double-sided transmission belt of the comparative example has a belt type conforming to the BB type, and is formed in the shape and dimensions shown in FIG.
The rubber layer 51 is formed by embedding a core wire 53 in an adhesive rubber layer 52, and an stretch rubber layer 55 and a compressed rubber layer 56 are formed on both surfaces of the rubber layer 51. Further, an outer cover 57 is formed on the outer circumference.
The stretched rubber layer 55 and the compressed rubber layer 56 are composed of the rubber composition A shown in Table 1. The adhesive rubber layer 52 constituting the rubber layer 51 is composed of the rubber composition B shown in Table 1.
For the core wire 53, a twisted cord of polyester fiber having an average wire diameter of 1.985 mm is used.
The shape and dimensions of the rubber layer 51 of the comparative example have the same shape and dimensions as the belt bases 2 of Examples 1 to 3.

As the outer cover cloth 54, a cotton woven cloth that has been subjected to an adhesive treatment is used.
This cotton woven fabric is formed by plain weave. Its fineness is composed of 20th warp and 20th weft. The yarn density of the warp and the weft is 75 threads / 50 mm, and the basis weight is 280 g / m2.
The bonding treatment is performed by a friction treatment with the rubber composition C in Table 1. This friction treatment is a treatment in which a rubber composition and a cloth are simultaneously passed between rolls rotating at different surface speeds using a calendar roll, and the rubber composition is rubbed between the cloths.

[Crack durability evaluation test]
The double-sided transmission belts of Examples 1 to 3 and Comparative Examples described above were subjected to a crack durability evaluation test using the two-motor multi-axis reverse bend traveling test apparatus shown in FIG.
The second motor multiaxial reverse bend travel trial KenSo location includes a drive pulley Dr outer diameter of 100 mm, a driven pulley Dn1 an outer diameter of 100 mm, a driven pulley Dn2 an outer diameter of 100 mm, an outer diameter of 60mm tension It has a pulley Tn. The drive pulley Dr and the driven pulleys Dn1 and Dn2 are V pulleys having a V groove.
The load when the tension pulley Tn applies tension to the belt was 40 kg, and the load of the drive pulley Dr was 4 ps. The rotation speed of the drive pulley Dr was set to 1800 rpm.
As the sample, the above-mentioned BB type 105 inch was used, and the number of hooks was one.

Using this test device, the double-sided transmission belts of Examples 1 to 3 and Comparative Examples were run.
Then, the POC elongation after running for 1 hour and after running for 24 hours, the belt temperature after running for 1 hour and after running for 24 hours, the crack occurrence time, and the belt cutting time were measured. The results are shown in Table 3 below.

In Table 3, [1] indicates sample 1 and [2] indicates sample 2.

As shown in Table 3, since Examples 1 to 3 have a structure having excellent flexibility, less heat generation, and good heat dissipation, the belt temperature is lower than that of the comparative example. As a result, it can be seen that the time required to cut the belt is more than doubled in Examples 1 to 3 as compared with Comparative Examples, which greatly contributes to the extension of life.

In Examples 1 to 3, the effect of the high-strength fiber sheet having excellent wear resistance and lateral pressure resistance is that the drop into the pulley is small, and as a result, the POC elongation is small. Further, the cracks that did not occur in Examples 1 to 3 occur at an early time in Comparative Example. Examples 1 to 3 show that the deformation (buckling deformation) is small and the breakage phenomenon such as interfacial peeling due to shear stress is unlikely to occur, despite the slight difference in the high-strength fiber sheets used.

Due to these synergistic effects, Examples 1 to 3 are excellent in wear resistance, lateral pressure resistance, buckling resistance, and low heat generation. Therefore, it can be seen that the belts are superior in durability as compared with Comparative Examples.

1 Double-sided transmission belt 2 Belt base 3 Outer peripheral protrusion 4 Inner peripheral protrusion 7 Outer peripheral transmission surface 8 Inner peripheral transmission surface 9 Flexible part

Claims (2)

A belt base having a flat hexagonal cross section and a continuous outer peripheral side transmission surface and a continuous inner peripheral side transmission surface formed on both side surfaces.
An outer peripheral protrusion that is provided on the outer peripheral surface of the belt base at predetermined intervals and forms an intermittent transmission surface that follows the continuous outer peripheral transmission surface.
An inner peripheral projection portion provided on the inner peripheral surface of the belt base at predetermined intervals and forming an intermittent transmission surface following the continuous inner peripheral side transmission surface is provided.
The belt base has an easily bendable portion in which neither the outer peripheral side protrusion nor the inner peripheral side protrusion is provided .
The outer circumferential side protrusion and the inner peripheral-side protrusions Ru moldings der containing high-strength fiber sheet having a high strength fiber bundles oriented in the width direction of the belt base in both sides transmission belts of the manufacturing method There,
A process of arranging high-strength fiber sheets that have been subjected to adhesive treatment on the inner and outer peripheral surfaces of an unvulcanized flat belt by wrapping them around to make an unvulcanized product.
A process in which the unvulcanized product is sandwiched between molded presses and integrally vulcanized and molded at the same time to obtain a vulcanized molded product.
A method for manufacturing a double-sided transmission belt, which comprises a step of cutting at a right angle in the width direction of the vulcanized molded product and further performing a bias cut. The method for manufacturing a double-sided transmission belt according to claim 1 , wherein the high-strength fiber sheet is a unidirectional sheet.

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