JP6943787B2 - Wrapped V-belt and its manufacturing method - Google Patents

Description

The present invention relates to a wrapped V-belt used for a belt-type clutch for agricultural machinery and the like, and a method for manufacturing the same.

The V-belt that transmits power by friction transmission includes a low-edge type (low-edge V-belt), which is a rubber layer with an exposed friction transmission surface, and an outer cloth (cover) on the friction transmission surface (V-shaped side surface). There is a wrapped type (wrapped V-belt) covered with cloth), and it is used properly according to the application due to the difference in the surface texture (friction coefficient between the rubber layer and the outer cover) of the friction transmission surface.

Usually, as the outer cover cloth (cover cloth), a cloth (canvas or the like) to which the rubber composition is attached is used for the purpose of ensuring the adhesiveness with the rubber layer inside. For example, a cloth obtained by soaking (immersing) a rubber paste in which a rubber composition is dissolved in a solvent or by friction-treating a solid rubber composition is used. Therefore, rubber is attached to the portion of the outer cover that appears on the belt surface.

For example, a wrapped V-belt is used for a belt type clutch for agricultural machinery, and the mechanism of this clutch will be described with reference to FIGS. 1 and 2. This mechanism is a mechanism for operating a clutch on a wrapped V-belt 1 suspended between a drive (Dr) pulley and a driven (Dn) pulley by using a clutch pulley (tension pulley) 2. As shown in FIG. 1, a mechanism is provided in which tension is applied to the belt when the clutch is ON to transmit power, and as shown in FIG. 2, the tension of the belt is relaxed when the clutch is OFF to shut off power transmission. In such a mechanism, in order to alleviate the impact when the clutch is turned on and to improve the clutch disengagement when the clutch is turned off, the amount of rubber adhered to the belt surface (the surface of the outer cover) is reduced as much as possible. A belt is used. This type of belt is also used in an environment where the rubber adhering to the outer cover cloth is prevented from scattering as rubber powder during traveling.

Regarding such a wrapped V-belt with a reduced amount of rubber adhered to the belt surface (surface of the outer cover), Utility Model Registration No. 30779705 (Patent Document 1) states that at least the portion of the cover canvas that appears on the belt surface is latex. A wrapped V-belt bonded with only a formalin-latex (RFL) solution is disclosed. Further, according to Japanese Patent No. 3404104 (Patent Document 2), the rubber on the surface of the canvas is removed and the rubber adheres only to the back surface of the canvas at the portion of the canvas layer in contact with both sides of the pulley grooves on both sides of the belt. The wrapped V-belt is disclosed.

However, even with these belts, rubber may ooze out from the openings such as the texture of the outer cover (the weave of the warp and the weft) on the surface of the belt during belt manufacturing.

Further, in this application, even when the belt is used (running), the rubber is easily exposed from the opening such as the texture of the outer cover due to the wear of the outer cover.

Specifically, when tension is applied to the belt by turning on the clutch pulley and power transmission is started, at the moment when the clutch pulley applies tension to the belt, a strong impact is applied to the transmission mechanism, and sudden tension is applied and the belt starts suddenly. do. Therefore, a forced slip is instantaneously generated between the belt and the Dr pulley, and the slip promotes wear of the contact surface with the pulley. As a result, when the opening such as the texture of the outer cover is widened due to wear, the rubber is exposed as rubber powder from the inside and adheres to the surface of the belt or the pulley.

When the tension of the belt is loosened by turning off the clutch pulley to shut off the power transmission, if rubber adheres to the surface of the belt, the adhesiveness of the rubber causes "carrying around" between the pulley and the belt, causing the clutch to disengage. Becomes worse. "Taking around" is a phenomenon in which the belt rotates with the rotation of the Dr pulley and the Dn pulley also rotates even after the clutch is disengaged. In particular, when the above-mentioned forced slip occurs continuously, this defect occurs remarkably.

Utility Model Registration No. 30779705 (Claim 1) Japanese Patent No. 3404104 (Claim 1)

Therefore, an object of the present invention is to provide a wrapped V-belt and a method for producing the same, which can suppress exudation of rubber during production and use and can reduce the amount of rubber adhered to the belt surface (surface of the outer cover).

Another object of the present invention is to provide a wrapped V-belt that can smoothly disengage a clutch, does not scatter rubber powder during use, and can run in a clean environment, and a method for manufacturing the same.

Still another object of the present invention is to provide a wrapped V-belt capable of suppressing breakage, wear, and dimensional change and improving durability, and a method for manufacturing the same.

As a result of diligent studies to achieve the above problems, the present inventors can suppress the exudation of rubber during manufacturing and use by interposing a thermoplastic resin layer between the outer cover and the belt body, and the belt. The present invention has been completed by finding that the amount of rubber adhered to the surface can be reduced.

That is, in the wrapped V-belt of the present invention, a thermoplastic resin layer is interposed between the outer cover and the belt body. The thermoplastic resin layer may contain polyolefin. In the wrapped V-belt of the present invention, the outer cloth may be a woven fabric, and the content ratio of the rubber component in the outer cloth may be 15% by mass or less with respect to the entire outer cloth. The average thickness of the outermost outer cloth is about 1 to 30 times the average thickness of the thermoplastic resin layer. The outer cover may include a first outer cloth located on the outermost surface and a second outer cloth, and a thermoplastic resin is provided between the first outer cloth and the second outer cloth. Layers may intervene.

In the present invention, a molded body for a thermoplastic resin layer is interposed between the outer cover and the main body of the unvulcanized belt, and the molded body for the thermoplastic resin layer is melt-heated to form a thermoplastic resin layer. A method for producing the wrapped V-belt including a step of forming a plastic resin layer is also included. The molded product for the thermoplastic resin layer may be a cloth (particularly a non-woven fabric). In the production method of the present invention, the unvulcanized belt body may be vulcanized by heating at a temperature equal to or higher than the melting point of the thermoplastic resin constituting the molded body for the thermoplastic resin layer, and the thermoplastic resin layer may be formed. ..

In the present invention, since the thermoplastic resin layer is interposed between the outer cover and the belt body, it is possible to suppress the exudation of rubber during manufacturing and use, and the amount of rubber adhered to the belt surface (the surface of the outer cover) can be reduced. Can be reduced. Specifically, when manufacturing a belt, it is possible to prevent rubber from oozing out to the surface of the belt from openings such as the texture of the outer cover. Further, when the belt is used, the clutch pulley reversely bends the belt in the clutch operation, and at the moment when a sudden tension is applied, a forced slip occurs between the belt and the Dr pulley, and the surface of the outer cover that comes into contact with the pulley is exposed. Even if it wears, it is possible to prevent the rubber inside from being exposed as rubber powder.

As a result, the amount of rubber adhered to the surface (the part that appears on the belt surface of the outer cover) is as small as possible, so there is no "carrying around" due to the adhesiveness of the rubber, and the clutch is disengaged (power transmission is cut off when the clutch is turned off). Can be done smoothly. Furthermore, there is no scattering of rubber powder during use (when the belt is running), and it is possible to run in a clean environment.

Further, when the outer cover is made of a specific cloth and the thermoplastic resin layer is made of polyolefin, breakage, abrasion, and dimensional change can be suppressed, and durability can be improved.

FIG. 1 is a schematic view showing a state in which the clutch is ON in a belt type clutch for agricultural machinery. FIG. 2 is a schematic view showing a state in which the clutch is OFF in the belt type clutch for agricultural machinery. FIG. 3 is a schematic cross-sectional view of an example of the wrapped V-belt of the present invention. FIG. 4 is a schematic cross-sectional view of another example of the wrapped V-belt of the present invention. FIG. 5 is a schematic view for explaining temporary fusion between the outer cover cloth and the molded body for the thermoplastic resin layer in the wrapped V-belt in which the outer cover cloth is 1 ply. FIG. 6 is a schematic view showing a state in which the unvulcanized belt main body of the wrapped V-belt having a 2-ply outer cover is covered with the outer cover and the molded product for the thermoplastic resin layer. FIG. 7 is a schematic view for explaining temporary fusion between the outer cover cloth and the molded body for the thermoplastic resin layer in the wrapped V-belt having the outer cover cloth of 2 plies. FIG. 8 is a schematic view showing a state in which the unvulcanized belt main body of the wrapped V-belt having a 2-ply outer cover is covered with the outer cover and the molded product for the thermoplastic resin layer. FIG. 9 is a schematic view for explaining a running test of the wrapped V-belt obtained in Examples and Comparative Examples. FIG. 10 is a schematic cross-sectional view of the wrapped V-belt obtained in the examples.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, if necessary.

In the wrapped V-belt of the present invention, the thermoplastic resin layer may be directly or indirectly interposed between the outer cover and the belt body, and the conventional wrapped V-belt is provided except that the thermoplastic resin layer is interposed. It may be a belt. A conventional wrapped V-belt includes an endless V-shaped cross-section belt body in which a core wire is embedded between a compression layer (compressed rubber layer) on the inner peripheral side and an extension layer (stretch rubber layer) on the outer peripheral side. It is composed of an outer cover cloth (cover cloth) that covers the circumference of the V-shaped cross section of the belt body over the entire length in the perimeter direction of the belt, and the left and right side surfaces of the V-shaped cross section covered with the outer cover cloth rub against each other. It may be a V-belt as a transmission surface.

FIG. 3 is a schematic cross-sectional view of an example of the wrapped V-belt of the present invention. As shown in FIG. 3, the wrapped V-belt 10 includes an stretch layer (stretch rubber layer or upper core rubber layer) 11a on the outer peripheral side of the belt, a compression layer (compression rubber layer or V-core rubber layer) 11c on the inner circumference side of the belt. An endless belt body 11 formed of a core body 11b embedded along the longitudinal direction (circumferential length direction) of the belt between the stretch layer 11a and the compression layer 11c, and the circumference of the belt around the belt body. It is formed of an outer cover cloth 12 (woven fabric, knitted fabric, non-woven fabric, etc.) covering the entire length in the direction, and a thermoplastic resin layer 13 interposed between the belt main body 11 and the outer cover cloth 12. In this example, the core body 11b is a core wire (twisted cord) arranged at predetermined intervals in the belt width direction, is in contact with the extension layer 11a and the compression layer 11c, and is interposed between the two layers. The wrapped V-belt is not limited to this structure, and for example, an adhesive layer is provided between the compression layer 11c and the extension layer 11a in order to improve the adhesiveness between the core body 11b and the extension layer 11a or the compression layer 11c. It may be intervened. The core body 11b may be embedded between the extension layer 11a and the compression layer 11c. For example, the core body 11b may be embedded in the compression layer 11c, and may be embedded in the compression layer 11c while being in contact with the extension layer 11a. May be good. Further, the core body 11b may be embedded in the adhesive layer, or may be embedded between the compression layer 11c and the adhesive layer or between the adhesive layer and the stretch layer 11a.

In this example, the thermoplastic resin layer can block the rubber composition of the rubber layer constituting the belt body from seeping out from the opening (texture) of the outer cover cloth. Further, the thermoplastic resin layer has a binder function, and the adhesion between the outer cover cloth and the belt body can be improved. Therefore, in the wrapped V-belt of the present invention, the outer cover does not require an adhesive treatment using a conventional adhesive component containing a rubber component, so that the amount of rubber adhered to the belt surface (outer cover surface) can be reduced. For example, since a fabric that has not been subjected to an adhesive treatment can be used, it is possible to manufacture a wrapped V-belt in which an adhesive component does not adhere to at least a portion of the outer cover that appears on the belt surface. On the other hand, with a conventional wrapped V-belt, the cloth alone cannot be sufficiently adhered to the belt body, so a cloth treated with an adhesive treatment agent containing an adhesive component (rubber component or resin component) is used as the outer cover. The rubber component contained in the adhesive treatment agent is exposed on the belt surface.

FIG. 4 is a schematic cross-sectional view of another example of the wrapped V-belt of the present invention. In this wrapped V-belt 20, the outer cover 22 has two plies (two layers), and is between the first outer cloth 22a on the surface side (outer layer) and the second outer cloth 22b on the belt body side (inner layer). The thermoplastic resin layer 23 is interposed therein, and the belt body is the same as the wrapped V-belt of FIG.

In this example, the first outer cloth 22a has a function as the outer cloth in FIG. 3, and the second outer cloth 22b may be the same as the conventional outer cloth. Therefore, the second outer cloth 22b is subjected to an adhesive treatment such as a treatment of soaking (immersing) a rubber paste in which a rubber composition is dissolved in a solvent, and a treatment of friction (rubbing) the solid rubber composition. It may be a cloth. That is, in order to enhance at least the adhesiveness of the second outer cover cloth 22b to the main body rubber layer, an adhesive treatment (adhesion of the rubber component) is required on the surface in contact with the main body rubber layer.

The details of the thermoplastic resin layer constituting the belt, the reinforcing cloth, the belt body, and the method for manufacturing the belt will be described below.

[Thermoplastic resin layer]
The thermoplastic resin layer contains a thermoplastic resin. The thermoplastic resin may be any thermoplastic resin that melts at the brewing temperature of the rubber composition constituting the rubber layer such as the compression layer and the stretch layer because it easily exhibits the binder function between the belt body and the outer cover. For example, polyolefin (polyethylene, polypropylene, etc.), styrene resin (polystyrene, acrylonitrile-butadiene-styrene resin, etc.), polycarbonate (aliphatic polycarbonate, etc.), polyamide (aliphatic polyamide, etc.), polyurethane (polyurethane type polyurethane, etc.), etc. Can be mentioned. These thermoplastic resins can be used alone or in combination of two or more.

The thermoplastic resin may be a crystalline resin such as polyethylene or polypropylene, or an amorphous resin such as polystyrene, but it is not brittle, has excellent wear resistance, and can prevent cracks. Sex resin is preferable. Further, polyolefin and / or polyurethane are preferable, and polyolefin is particularly preferable, from the viewpoint of excellent versatility.

Among the polyolefins, polyethylene-based resins such as polyethylene and polypropylene-based resins such as polypropylene are preferable.

Examples of the polyethylene-based resin include low-, medium- or high-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, and the like. Examples thereof include an ethylene- (4-methylpentene-1) copolymer. These polyethylene-based resins can be used alone or in combination of two or more. Of these polyethylene-based resins, low-density polyethylene is preferable.

Examples of the polypropylene-based resin include polypropylene, a copolymer of propylene and a copolymerizable monomer (a binary copolymer such as a propylene-ethylene copolymer and a propylene- (meth) acrylic acid copolymer; propylene-. A ternary copolymer such as ethylene-butene-1) and the like are included. These polypropylene-based resins can be used alone or in combination of two or more. Among these polypropylene-based resins, a homopolymer of propylene such as polypropylene is preferable.

Of these, polypropylene-based resins such as polypropylene are preferable because they easily melt at the vulcanization temperature and also have appropriate heat resistance, and they easily melt to exhibit a binder function and improve the durability of the belt. A polyethylene-based resin such as low-density polyethylene is particularly preferable from the viewpoint of being able to do so. It can be presumed that the use of the polyethylene-based resin is excellent in melt fluidity and therefore sufficiently penetrates into the outer cover, so that the adhesive force between the outer cover and the rubber can be improved, which leads to the stability of belt running.

The melting point of the thermoplastic resin may be equal to or lower than the vulcanization temperature of the belt body and the rubber composition for forming the main body, and is 0 to 100 ° C., preferably 3 to 80 ° C., more preferably 5 to 5 degrees Celsius from the vulcanization temperature. It has a melting point as low as 70 ° C (particularly 10-60 ° C). Usually, the melting point is about 100 to 180 ° C., preferably 110 to 175 ° C., more preferably 130 to 173 ° C. (particularly 160 to 170 ° C.).

Thermoplastic resin layers can be optionally added to conventional additives such as enhancers, fillers, metal oxides, plasticizers, processing agents or processing aids, colorants, coupling agents, stabilizers (ultraviolet absorption). Agents, antioxidants, ozone degradation inhibitors, heat stabilizers, etc.), lubricants, flame retardants, antistatic agents, etc. may be included. The ratio of the additive is about 10% by mass or less (for example, 0.1 to 5% by mass) with respect to the entire thermoplastic resin layer. That is, the ratio of the thermoplastic resin to the entire thermoplastic resin layer may be 90% by mass or more, or may be substantially formed of only the thermoplastic resin.

The average thickness of the thermoplastic resin layer is, for example, 0.01 to 0.5 mm, preferably 0.02 to 0.3 mm, more preferably 0.03 to 0.25 mm (particularly 0.05 to 0.2 mm). be. If the thickness of the thermoplastic resin layer is too thin, the rubber component may exude, and if it is too thick, the mechanical properties of the belt may deteriorate.

The form of the raw material (molded body for the thermoplastic resin layer) of the thermoplastic resin layer is not particularly limited, and is usually in the form of particles, a sheet, a fiber, or the like. Of these forms, the fibrous form is preferable from the viewpoint of improving belt productivity. As the fibrous raw material, a non-woven fabric, a woven cloth, a knitted cloth and the like can be used, and the non-woven fabric can be preferably used.

When the thermoplastic resin layer is obtained by using a cloth having a fiber structure, the fiber structure derived from the raw material may disappear or may remain. Further, the thermoplastic resin layer may have a structure in which a fibrous portion in which the fibrous shape remains and a non-fibrous portion in which the fibrous shape has disappeared are mixed. The ratio of the non-fibrous portion to the entire thermoplastic resin layer is usually 80% or less, and is, for example, 50% or less, preferably 30% or less, and more preferably 10% or less from the viewpoint of excellent binder function. In the present specification and claims, the ratio of the non-fibrous portion is calculated as the area ratio in the cross-sectional area based on the electron micrograph of the cross-sectional area.

The basis weight of the raw material fabric (particularly non-woven fabric) ^{can be selected from the range of about 10 to 50 g / m 2} , for example, 12 to 30 g / m ² , preferably 13 to 28 g / m ² , and more preferably 15 to 25 g / m 2. It is about m ^2.

The average thickness of the fabric (particularly the non-woven fabric) is, for example, 0.01 to 0.5 mm, preferably 0.03 to 0.3 mm, more preferably 0.05 to 0.25 mm (particularly 0.14 to 0.23 mm). Degree.

The surface of the thermoplastic resin layer on the side in contact with the belt body may be adhesively treated in order to improve the adhesiveness with the belt body. Examples of the adhesive treatment include a resin-based treatment liquid in which an adhesive component [for example, an epoxy compound, an isocyanate compound] is dissolved in an organic solvent (toluene, xylene, methyl ethyl ketone, etc.), a resorcin-formaline-latex liquid (RFL liquid), and the like. Examples thereof include surface treatment (for example, coating treatment) with an adhesive treatment agent such as rubber glue in which the rubber composition is dissolved in an organic solvent. The ratio of the adhesive treatment agent (solid content) is about 30% by mass or less (for example, 0.01 to 10% by mass) with respect to the entire thermoplastic resin layer. When the raw material of the thermoplastic resin layer is a cloth such as a non-woven fabric, the adhesive component that has been bonded may form a film on the belt body side of the thermoplastic resin layer, and may be mixed with the thermoplastic resin at the interface or mixed with the thermoplastic resin. It may be compounded.

[Outer cloth]
The outer cover is made of a conventional cloth. Examples of the cloth include woven cloth, knitted cloth (weft knitted cloth, warp knitted cloth), and cloth materials such as non-woven fabric. Of these, woven fabrics woven in the form of plain weave, twill weave, red weave, etc., woven fabrics woven at a wide angle of more than 90 ° and 120 ° or less at the intersection angle of the warp and weft, and the like are preferable. Woven cloth that is widely used as a cover cloth for transmission belts for general industry and agricultural machinery [plain woven cloth in which the crossing angle between the warp and weft is perpendicular, and the crossing angle between the warp and weft exceeds 90 ° and 120 °. A plain woven cloth (wide-angle canvas) having a wide angle of the following degree is particularly preferable. Further, in applications where durability is required, a wide-angle canvas may be used.

Examples of the fibers constituting the fabric include polyolefin fibers (polyethylene fibers, polypropylene fibers, etc.), polyamide fibers (polyamide 6 fibers, polyamide 66 fibers, polyamide 46 fibers, aramid fibers, etc.), and polyalkylene allylate fibers [polyethylene]. _{Poly C 2-4alkylene} C _8-14 allylate fiber such as terephthalate (PET) fiber, polyethylene naphthalate (PEN) fiber], vinyl alcohol fiber (polyvinyl alcohol fiber, ethylene-vinyl alcohol copolymer fiber, vinylon) Fibers, etc.), synthetic fibers such as polyparaphenylene benzobisoxazole (PBO) fibers; natural fibers such as cellulose-based fibers and wool; inorganic fibers such as carbon fibers are widely used. These fibers may be single yarns used alone, or may be blended yarns in which two or more kinds are combined.

Among these fibers, it is preferable to contain cellulosic fibers from the viewpoint of excellent mechanical properties and economic efficiency. The ratio of the cellulosic fiber may be 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and 100% by mass with respect to the entire fiber.

Cellulose-based fibers include cellulosic fibers (cellulosic fibers derived from plants, animals, bacteria, etc.) and fibers of cellulose derivatives. Examples of cellulose fibers include wood pulp (coniferous tree, broadleaf tree pulp, etc.), bamboo fiber, sugar cane fiber, seed hair fiber (cotton fiber (cotton linter), capoc, etc.), ginseng fiber (hemp, kozo, mitsumata, etc.), Examples thereof include natural plant-derived cellulose fibers (pulp fibers) such as leaf fibers (Manila hemp, New Zealand hemp, etc.); animal-derived cellulose fibers such as squirrel cellulose; bacterial cellulose fibers; and algae cellulose. Examples of the fibers of the cellulose derivative include cellulose ester fibers; regenerated cellulose fibers (rayon, cupra, lyocell, etc.).

The average fineness of the fibers constituting the fabric is, for example, 5 to 30 counts, preferably 10 to 25 counts, and more preferably 10 to 20 counts.

The basis weight of the cloth (raw material cloth) is, for example, 100 to 500 g / m ² , preferably 200 to 400 g / m ² , and more preferably about 250 to 350 g / m ^2.

When the fabric (raw material fabric) is a woven fabric, the yarn density (density of warp and weft) of the fabric is, for example, 60 to 100 threads / 50 mm, preferably 70 to 90 threads / 50 mm, and more preferably 75 to 85 threads / 50 mm. Degree.

The outer cover may be a single layer or a multi-layer (for example, 2 to 5 layers, preferably 2 to 4 layers, more preferably about 2 to 3 layers), but from the viewpoint of productivity and the like. A single layer (1 ply) or 2 layers (2 plies) is preferable. Further, from the viewpoint of durability, a multilayer is preferable, and from the viewpoint of excellent balance between productivity and durability, two layers are particularly preferable.

Since the wrapped V-belt of the present invention has a thermoplastic resin layer, the outer cover cloth (particularly, the outer cover cloth in a single layer or the outer coat cloth in the outermost layer in a multi-layer structure) is subjected to an adhesive treatment for improving the adhesiveness with the belt body. Is not required, but depending on the type of fabric, a resin-based treatment liquid in which an adhesive component [for example, epoxy compound, isocyanate compound] is dissolved in an organic solvent (toluene, xylene, methyl ethyl ketone, etc.) or resorcin-formaline-latex Adhesion treatment may be performed using a liquid (RFL liquid). In particular, when the cloth is a wide-angle canvas, it may be fixed with a heat-treated product of RFL liquid in order to fix the angle.

The outer cloth (particularly the outer cloth in a single layer or the outer cloth in the outermost layer in a multi-layer) has a low content of rubber component unlike the outer cloth of the conventional wrapped V-belt. For example, the ratio of the rubber component is the outer cloth. It is about 15% by mass or less (for example, 1 to 10% by mass), preferably 5% by mass or less, and more preferably 1% by mass or less (for example, 0.01 to 1% by mass) with respect to the whole. If the content of the rubber component is too large, exudation of rubber may become a problem. In the present invention, since the content of the rubber component of the outer cover is small, it is possible to suppress the exudation of rubber from the outer cover itself.

The outer coat (particularly the outer coat in a single layer or the outermost outer coat in a multilayer) further contains the additives and / or short fibers exemplified in the section of the belt body (compression layer and stretch layer) described later. May be good. The total ratio of the additive and the short fiber is about 10% by mass or less (for example, 0.1 to 5% by mass) with respect to the entire outer cover. That is, the ratio of the cloth to the entire outer cloth may be 90% by mass or more, or may be substantially formed only of the cloth.

When the outer cover is multi-layered, the outer cover other than the outermost layer may be a conventional outer cover. The conventional outer cover cloth may be a cloth to which a rubber component is attached in order to improve the adhesiveness with the belt body. The outer cloth to which the rubber component is attached is a cloth that has undergone an adhesive treatment such as a treatment of soaking (immersing) a rubber paste in which a rubber composition is dissolved in a solvent, or a treatment of friction (rubbing) a solid rubber composition. It may be. In particular, it is particularly preferable that the outer cover other than the outermost layer is subjected to an adhesive treatment on the surface in contact with the belt body to adhere the rubber component, at least in order to enhance the adhesiveness with the belt body.

The average thickness of the outer cover (in the case of multiple layers, the average thickness of each layer) can be appropriately selected depending on the type of belt and the like, but is, for example, 0.4 to 2 mm, preferably 0.5 to 1.4 mm, and more preferably 0. It may be about 6 to 1.2 mm. If the thickness of the outer cover is too thin, the heat dissipation of the rubber may be lowered, and if it is too thick, the bending resistance of the belt may be lowered. In the present specification and claims, the average thickness of the outer cover can be measured based on a scanning electron micrograph (SEM), and is obtained as an average value of any five or more points.

The average thickness of the outer cover (in the case of multiple layers, the average thickness of the first outer cover on the outermost surface) is, for example, 1 to 30 times, preferably 2 to 20 times, more than the average thickness of the thermoplastic resin layer. It is preferably about 3 to 15 times (particularly 5 to 10 times). If the average thickness of the outer cover is too small, the wear resistance may decrease, and if it is too large, the rubber component may exude.

[Belt body]
The vulture rubber forming the compression layer and the stretch layer can be selected from known rubber components and / or elastomers. For example, diene rubber (natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, styrene butadiene rubber (SBR)). , Acrylonitrile butadiene rubber (nitrile rubber), hydride nitrile rubber (including mixed polymer of hydride nitrile rubber and unsaturated carboxylic acid metal salt), ethylene-α-olefin elastomer, chlorosulfonated polyethylene rubber, alkylation Examples thereof include chlorosulfonated polyethylene rubber, epichlorohydrin rubber, acrylic rubber, silicone rubber, urethane rubber, and fluororubber. These ingredients can be used alone or in combination. Among these rubber components, diene rubber (natural rubber, chloroprene rubber, hydride nitrile rubber, etc.), ethylene-α-olefin elastomer (ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM, etc.), etc.) Ethylene-α-olefin rubber) and the like are preferable, and chloroprene rubber is particularly preferable.

The ratio of the rubber component to the entire compressed layer or stretched layer (or the total amount of the rubber composition) is, for example, 20% by mass or more (for example, 25 to 80% by mass), preferably 30% by mass or more (for example, 35 to 75% by mass), and further. It may be preferably 40% by mass or more (particularly 45 to 70% by mass).

The compressed layer or the stretched layer (or the rubber composition forming these layers) is a vulcanizing agent or a cross-linking agent selected according to the type of rubber component [for example, a sulfur-based vulcanizing agent (sulfur, sulfur chloride, etc.)). , Oxims (quinonedioximes, etc.), guanidines (diphenylguanidine, etc.), organic peroxides (diacyl peroxide, peroxyester, dialkyl peroxide, etc.), metal oxides (magnesium oxide, zinc oxide, etc.)] , Vulcanization aid, vulcanization accelerator, vulcanization retarder and the like may be included. The ratio of the vulcanizing agent or the cross-linking agent is about 1 to 20 parts by mass (particularly 2 to 15 parts by mass) with respect to 100 parts by mass of the rubber component. The ratio of the vulcanization aid is about 0.01 to 10 parts by mass (particularly 0.1 to 5 parts by mass) with respect to 100 parts by mass of the rubber component. The ratio of the vulcanization accelerator is about 0.1 to 15 parts by mass (particularly 0.3 to 10 parts by mass) with respect to 100 parts by mass of the rubber component.

The compressed layer or the stretched layer may further contain various additives. Examples of the additive (blending agent) include known additives such as reinforcing agents (carbon black, silicon oxide such as hydrous silica), short fibers (cellulose fibers such as cotton and rayon, polyester fibers, and polyamide fibers). Metal oxides (eg zinc oxide, magnesium oxide, calcium oxide, barium oxide, iron oxide, copper oxide, titanium oxide, aluminum oxide, etc.), fillers (clay, calcium carbonate, talc, mica, etc.), plastics Agents, softeners (oils such as paraffin oil and naphthenic oil), processing agents or processing aids (stearic acid, metal stearate, wax, paraffin, etc.), antiaging agents (aromatic amine antiaging agents) , Benzimidazole anti-aging agent, etc.), Adhesive improver [Resolsin-formaldehyde cocondensate, melamine resin such as hexamethoxymethylmelamine, cocondensate of these (resorcin-melamine-formaldehyde cocondensate, etc.)], Examples thereof include colorants, tackifiers, coupling agents (silane coupling agents, etc.), stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), lubricants, flame retardants, antistatic agents, and the like. These additives can be used alone or in combination, and these additives can be selected according to the type, application, performance and the like of the rubber.

The ratio of the additive can be appropriately selected according to the type of rubber component and the like. For example, the ratio of the reinforcing agent (carbon black or the like) is 10 parts by mass or more (for example, 20 to 150 parts by mass), preferably 20 parts by mass or more (for example, 25 to 120 parts by mass), more preferably, with respect to 100 parts by mass of rubber. May be 30 parts by mass or more (for example, 35 to 100 parts by mass), particularly 40 parts by mass or more (for example, 50 to 80 parts by mass).

The thickness of the compression layer can be appropriately selected depending on the type of belt and the like, and may be, for example, 1 to 30 mm, preferably 1.5 to 25 mm, and more preferably 2 to 20 mm.

The thickness of the stretch layer can be appropriately selected depending on the type of belt and the like, but may be, for example, 0.5 to 10 mm, preferably 0.7 to 8 mm, and more preferably about 1 to 5 mm.

The adhesive layer is not always necessary, as described above. The adhesive layer (adhesive rubber layer) can be composed of, for example, a rubber composition similar to the compression layer (a rubber composition containing a rubber component such as chloroprene rubber). The rubber composition of the adhesive layer may further contain an adhesiveness improving agent (resorcin-formaldehyde cocondensate, amino resin, etc.).

The thickness of the adhesive layer may be, for example, 0.2 to 5 mm, preferably 0.3 to 3 mm, and more preferably about 0.5 to 2 mm.

In the rubber composition of the compression layer, the stretch layer, and the adhesive layer, rubber of the same type or the same type is often used as the rubber component.

The core body is not particularly limited, but usually, core wires (twisted cords) arranged at predetermined intervals in the belt width direction can be used. The core wire is not particularly limited, and may include, for example, synthetic fibers such as polyester fibers (polyalkylene allylate fibers), polyamide fibers (aramid fibers and the like), and inorganic fibers such as carbon fibers.

As the core wire, a twisted cord using a multifilament yarn (for example, various twists, single twist, rung twist, etc.) can be usually used. The average wire diameter of the core wire (fiber diameter of the twisted cord) may be, for example, 0.5 to 3 mm, preferably 0.6 to 2 mm, and more preferably about 0.7 to 1.5 mm. The core wire may be embedded in the longitudinal direction of the belt, or may be embedded in parallel at a predetermined pitch parallel to the longitudinal direction of the belt.

In order to improve the adhesiveness with the rubber component, the core wire may be surface-treated (adhesive-treated) with a surfactant, a silane coupling agent, an epoxy compound, an isocyanate compound, or the like, if necessary.

[Manufacturing method of wrapped V-belt]
In the wrapped V-belt of the present invention, a molded body for a thermoplastic resin layer is interposed between the outer cover and the main body of the unrefined belt, and the molded body for the thermoplastic resin layer is melt-heated to form the thermoplastic resin layer. It is obtained through the thermoplastic resin layer forming step of forming, and for the steps other than the thermoplastic resin layer forming step, the steps in the conventional manufacturing method of the wrapped V-belt can be used. As a method for manufacturing the wrapped V-belt, for example, the methods described in JP-A-6-137381 and WO2015 / 104778 pamphlets can also be used.

As a method for manufacturing the unvulcanized belt body, a conventional method can be used. For example, an unvulcanized compression layer sheet obtained by rolling is cut and set in the mantle, and then the core body is wound and wound. A winding process in which an unvulcanized stretch layer sheet is further wound on the core body, a cutting process in which the obtained annular laminate is cut (round sliced) on the mantle, and the cut annular laminate is combined into a pair of pulleys. It can be obtained through a vulcanization process in which the product is cut into a V shape while being bridged and rotated. In the conventional method, the obtained unvulcanized belt body is wrapped (coated) with an outer cover and subjected to a vulcanization step, but in the method of the present invention, a molded product for a thermoplastic resin layer is temporarily fused. It may be wrapped with the outer cover cloth and subjected to the vulcanization step, or after wrapping the molded product for the thermoplastic resin layer, it may be wrapped with the outer cover cloth and subjected to the vulcanization step. In the unvulcanized belt body wrapped with the outer cover and the molded body for the thermoplastic resin layer, the molded body for the thermoplastic resin layer is melt-heated by this vulcanization step to form the thermoplastic resin layer.

Specifically, when the outer cover is a single layer and the molded product for the thermoplastic resin layer (particularly, the non-woven fabric) is temporarily fused to the outer cover, for example, as shown in FIG. 5, before wrapping, one side. The outer cover 33 is temporarily fused to the other surface of the molded body 31 for the thermoplastic resin layer whose surface is bonded 32, and the unvulcanized belt body is wrapped with the obtained laminate. , May be subjected to a vulcanization step. In this example, the molded product for the thermoplastic resin layer is bonded, but the molded product for the thermoplastic resin layer may not be bonded.

The temperature for temporary fusion is preferably lower than the temperature at which the molded body for the thermoplastic resin layer is melt-heated to form the thermoplastic resin layer in the thermoplastic resin layer forming step. Specifically, the temperature of the temporary fusion is a temperature equal to or lower than the melting point of the thermoplastic resin constituting the molded body for the thermoplastic resin layer, for example, 0 to 50 ° C., preferably 3 to 40 ° C., more preferably 3 to 40 ° C. from the melting point. The temperature may be 5 to 30 ° C. lower. If the temperature of the temporary fusion is too high, the productivity may decrease.

When the outer cover is a single layer and the molded body for the thermoplastic resin layer is not temporarily fused to the outer cover, for example, as shown in FIG. 6, the molded body 31 for the thermoplastic resin layer that has been subjected to the adhesive treatment 32. Then, the adhesive-treated surface is brought into contact with the unvulcanized belt main body 34 to wrap the unvulcanized belt main body 34, and then the thermoplastic resin molded body 31 is wrapped with the outer cover 33 and subjected to the vulcanization step. May be good.

On the other hand, when the outer cover has two layers and the molded product for the thermoplastic resin layer is temporarily fused to the first outer cover, which is the outermost layer, for example, as shown in FIG. 7, the thermoplastic is plastic before wrapping. The first outer cover 42 of the outermost layer is temporarily fused to one surface of the resin layer molded body 41, and the second outer cloth 43 having both sides bonded 44 is temporarily fused to the other surface. Then, the unvulcanized belt body may be wrapped with the obtained laminate and subjected to the vulcanization step. In this example, both sides of the second outer cover are bonded, but the surface in contact with the molded product for the thermoplastic resin layer does not have to be bonded. Further, the temporary fusion may be performed on only one of the surfaces.

When the outer cover has two layers and the molded product for the thermoplastic resin layer is not temporarily fused to the outer cover, for example, as shown in FIG. 8, the second outer cloth 43 having both sides bonded to 44 is bonded. After wrapping the unvulcanized belt body 45, the second outer cloth 43 is wrapped with the thermoplastic resin layer molded body 41, and further, the first outer cloth 42 is used to mold the thermoplastic resin layer. The body 41 may be wrapped and subjected to a vulcanization step.

In the thermoplastic resin layer forming step, the method for forming the thermoplastic resin layer by melting and heating the molded body for the thermoplastic resin layer is not particularly limited, but from the viewpoint of productivity and the like, the vulcanization step of the belt body is added. It is preferable to form the thermoplastic resin layer at the vulcanization temperature. The vulcanization temperature can be selected according to the type of rubber component, and is, for example, 120 to 200 ° C, preferably about 150 to 180 ° C.

Specifically, according to the embodiment shown in FIGS. 5 to 8, the unvulcanized unvulcanized belt main body wrapped with the thermoplastic resin layer molded body and the outer cover is attached to the mold, and vulcanization molding is performed. , A vulcanized wrapped V-belt is obtained. That is, with the completion of the wrapped V-belt, a thermoplastic resin layer is also formed at the same time, and the outer cover and the belt body are integrated with the thermoplastic resin layer interposed therebetween. For example, when the molded body for the thermoplastic resin layer is a non-woven fabric, the thermoplastic fibers constituting the non-woven fabric are melted into a non-fibrous or partially non-fibrous form in vulcanization (heat treatment) and solidified by cooling. .. The heat-treated non-woven fabric serves as a binder between the rubber layer of the belt body and the outer cover, and the outer cloth and the belt body are integrated, and the belt is interposed as a thermoplastic resin layer between the two.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The raw materials used for the rubber composition, the method for preparing the rubber composition, the fiber materials used, the method for measuring or evaluating each physical property, and the like are shown below.

[Raw materials used for rubber compositions]
Chloroprene rubber: "PM-40" manufactured by DENKA Co., Ltd.
Magnesium oxide: "Kyowa Mag 30" manufactured by Kyowa Chemical Industry Co., Ltd.
Stearic acid: NOF CORPORATION "Stearic acid camellia"
Anti-aging agent: "Non-flex OD-3" manufactured by Seiko Chemical Co., Ltd.
Carbon Black: "Seast 3" manufactured by Tokai Carbon Co., Ltd.
Plasticizer: "RS-700" manufactured by ADEKA Corporation
Vulcanization accelerator: "Noxeller TT" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.
Zinc oxide: "Zinc oxide 3 types" manufactured by Shodo Chemical Industry Co., Ltd.

[Sheet-like rubber composition for compression layer, stretch layer or adhesive layer]
The rubber composition of Formulation A shown in Table 1 is kneaded with a Banbury mixer, and the kneaded rubber is passed through a calendar roll to prepare an unvulcanized rolled rubber sheet having a predetermined thickness as a compression layer sheet and an extension layer sheet, respectively. bottom. Further, using the rubber composition of Formulation B shown in Table 1, a sheet for an adhesive layer was prepared in the same manner as described above.

[Friction lump rubber composition]
The rubber composition of Formulation C shown in Table 2 was rubber-kneaded with a Banbury mixer to prepare a massive unvulcanized rubber composition for friction.

[Fiber material used]
Table 3 shows the fiber materials used to form the core wire, the outer cover and the thermoplastic resin layer.

[Average thickness of outer cover and thermoplastic resin layer]
The average thickness of the outer cover and the thermoplastic resin layer was determined by measuring the thicknesses of five or more arbitrary points using a scanning electron micrograph (SEM) and averaging them.

[Belt running test]
Using the wrapped V-belts obtained in Examples and Comparative Examples, as shown in FIG. 9, a drive (Dr) pulley having a diameter of 80 mm, a driven (Dn) pulley having a diameter of 160 mm, and a tension (Ten) pulley having a diameter of 60 mm were used. Using the arranged testing machine, the belt was run for 300 hours under the conditions shown in Table 4, and various characteristics were evaluated. In this test, the belt is momentarily tensioned by the clutch operation, and when the tensioned belt suddenly starts, it is forced to slip with the Dr pulley (the pulley is rotating, but the belt is the pulley. It cannot follow the rotation).

Example 1
A sheet for a compression layer, a sheet for an adhesive layer, a core wire, and a sheet for an extension layer are sequentially laminated and attached to the outer peripheral surface of a cylindrical drum, and a tubular shape in which an unvulcanized rubber layer and a core wire are laminated. Unvulcanized sleeve was formed. The obtained unvulcanized sleeve was cut in the circumferential direction while being arranged on the outer periphery of the cylindrical drum to form an annular unvulcanized rubber belt.

Next, the unvulcanized rubber belt was removed from the drum, and both side surfaces of the unvulcanized rubber belt were cut (skived) at a predetermined angle to form a V-shaped cross section of the unvulcanized rubber belt. As shown in FIG. 10, a non-woven fabric A (thermoplastic resin) is surrounded by an unvulcanized rubber belt 51 (a belt composed of an stretch layer 51a, a core wire 51b, an adhesive layer 51c, and a compression layer 51d) having a V-shaped cross section. An unvulcanized belt molded body was formed by sequentially covering with a low-density polyethylene non-woven fabric 53 for forming a layer and a woven fabric A (cotton woven fabric for forming an outer cover) 52.

The obtained unvulcanized belt molded body was inserted into the concave groove of the ring mold. Further, in a state where a cylindrical rubber sleeve is fitted on the outer peripheral surface of the ring mold and the unvulcanized belt molded body, they are stored in a vulcanization can and vulcanized at a vulcanization temperature of 160 ° C. Got The obtained vulcanization belt was removed from the ring mold to obtain a B-shaped wrapped V-belt (JIS K6323, cross-sectional dimensions: width 16.5 mm x thickness 11.0 mm, belt length 44 inches). The average thickness of the outer cover was 0.5 mm, and the average thickness of the thermoplastic resin layer was 0.05 mm. The proportion of non-fibrous portions in the thermoplastic resin layer was 10%. The composition of each layer of the obtained wrapped V-belt is shown in Table 5, and the evaluation results of the running test are shown in Table 6.

Example 2
A wrapped V-belt was obtained in the same manner as in Example 1 except that the woven fabric B was used instead of the woven fabric A as the cotton woven fabric for forming the outer cover. The composition of each layer of the obtained wrapped V-belt is shown in Table 5, and the evaluation results of the running test are shown in Table 6.

Example 3
A wrapped V-belt was obtained in the same manner as in Example 1 except that the non-woven fabric B was used instead of the non-woven fabric A as the non-woven fabric for forming the thermoplastic resin layer. The composition of each layer of the obtained wrapped V-belt is shown in Table 5, and the evaluation results of the running test are shown in Table 6.

Example 4
A wrapped V-belt was obtained in the same manner as in Example 1 except that the non-woven fabric C was used instead of the non-woven fabric A as the non-woven fabric for forming the thermoplastic resin layer. The composition of each layer of the obtained wrapped V-belt is shown in Table 5, and the evaluation results of the running test are shown in Table 6.

Example 5
As shown in FIGS. 7 and 8, instead of the non-woven fabric A and the woven fabric A, the non-woven fabric A, the non-woven fabric A, and the non-woven fabric A which have not been subjected to the friction treatment are used for the unrefined rubber belt having a V-shaped cross section. A wrapped V-belt was obtained in the same manner as in Example 1 except that the cover winding treatment was sequentially applied. In the friction-treated woven fabric A, the friction lump rubber composition is passed through the gap between two rolls having different surface speeds at the same time as the woven fabric only on one side in contact with the belt body of the woven fabric A. Friction treatment was performed by rubbing rubber into the cloth. The composition of each layer of the obtained wrapped V-belt is shown in Table 5, and the evaluation results of the running test are shown in Table 6.

Comparative Example 1
Friction treatment was performed by passing the friction lump rubber composition through the gap between two rolls having different surface speeds at the same time as the woven cloth and rubbing the rubber into the cloth on only one side in contact with the belt body of the woven cloth A. .. A wrapped V-belt was obtained in the same manner as in Example 1 except that the friction-treated woven fabric A was used as the woven fabric for forming the outer cover and the non-woven fabric A was not used. The composition of each layer of the obtained wrapped V-belt is shown in Table 5, and the evaluation results of the running test are shown in Table 6.

From the results in Table 6, the belt of Comparative Example 1 in which the rubber is exposed due to bleeding has a large coefficient of friction, and in particular, the belt side surface wear is promoted when it comes into contact with the V pulley. On the other hand, in Examples 1 to 5, since there is no bleeding and the friction coefficient is extremely small, the pulley slides on the belt, so that the side surface wear is small.

For the above reasons, in the examples, the change in dimension (width) was small and the amount of wear on the side surface was also small. The difference in the amount of side wear appears in the side condition. In the comparative example where the rubber is exposed due to the acceleration of wear, it often goes around. When the escort occurs, the work connected to the driven side does not stop completely, which causes problems and dangers. Further, in the comparative example, the heat generated during wear was high, and the rubber was cured at an early stage, so that a plurality of cracks (cracks) were generated in the compressed rubber, but the breakage phenomenon (cracks / cracks) did not occur in the example with less wear. .. The instantaneous pronunciation when tension is applied to the belt when the clutch is operated is a sensory evaluation by listening, but there is a difference.

The wrapped V-belt of the present invention can be used for general industrial machines such as compressors, generators and pumps, and agricultural machines such as combiners, rice transplanters and mowing machines, and is suitable for agricultural machines that operate clutches using tension pulleys. There is.

1,10 ... Wrapped V-belt 2 ... Clutch pulley 11 ... Belt body 12,22 ... Outer cloth 13,23 ... Thermoplastic resin layer

Claims (7)

A wrapped V-belt in which a thermoplastic resin layer is interposed between the outer cover and the belt body.
The outer cover cloth is a woven cloth having a thread density of 60 to 100 threads / 50 mm.
The content ratio of the rubber component in the outer cover is 15% by mass or less with respect to the entire outer cloth, and
A wrapped V-belt in which the average thickness of the outermost outer cloth is 1 to 30 times the average thickness of the thermoplastic resin layer . The wrapped V-belt according to claim 1, wherein the thermoplastic resin layer contains polyolefin. A claim in which the outer cover includes a first outer cloth located on the outermost surface and a second outer cloth, and a thermoplastic resin layer is interposed between the first outer cloth and the second outer cloth. Item 1 or 2, the wrapped V-belt. A step of forming a thermoplastic resin layer in which a molded body for a thermoplastic resin layer is interposed between the outer cover cloth and the main body of the unrefined belt, and the molded body for the thermoplastic resin layer is melt-heated to form a thermoplastic resin layer. The method for manufacturing a wrapped V-belt according to any one of claims 1 to 3. The manufacturing method according to claim 4 , wherein the molded body for the thermoplastic resin layer is a cloth. The manufacturing method according to claim 5 , wherein the fabric is a non-woven fabric. Heating a thermoplastic at a temperature higher than the melting point of the resin constituting the thermoplastic resin layer molded article with vulcanizing unvulcanized belt body, according to any one of claims 4-6 to form a thermoplastic resin layer Manufacturing method.

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