Toothed belt

Abstract

To provide a toothed belt which suppresses permanent elongation and has improved flexibility. [Solution] A toothed belt (1) comprises a rubber layer (4) having a toothed rubber portion (42) on at least one surface side, a plurality of core wires (5) embedded in the rubber layer (4), an adhesive layer (31) adhered to the surface side of the rubber layer (4) on which the toothed rubber portion (42) is provided, and an impregnation layer (32) formed on the surface of the adhesive layer (31) and formed by impregnating a raw canvas with rubber, and a tooth cloth (3) adhered to the surface of the rubber layer (4) having the toothed rubber portion (42) and to the surface of the toothed rubber portion (42). The adhesive layer (31) contains an organic peroxide, the core wires (5) contain a latex component inside, and the adhesion area between the core wires (5) and the adhesive layer (31) is 40% or more and 50% or less of the surface area of ​​the core wires (5).

Description

[Technical field]

[0001] The present invention relates to a toothed belt. [Background technology]

[0002] Toothed belts used as power transmission belts, timing belts, etc. are placed around pulleys and are used under heavy loads, and are therefore required to maintain various performance characteristics for a long period of time.

[0003] For example, Patent Document 1 describes that the rubber layers (back rubber layer and tooth rubber layer) are made of an organic peroxide crosslinking rubber composition, and toothed canvas coated with a crosslinking rubber composition containing organic peroxide and sulfur is bonded to the toothed rubber layer. This not only improves the heat aging resistance and abrasion resistance of the toothed belt, but also makes the toothed belt less likely to stretch. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-208556 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional technology, although the coating layer of the toothed canvas is crosslinked by an organic peroxide, the elongation of the toothed belt can be suppressed, but there is still room for improvement in the suppression of elongation. In particular, there is a problem that the so-called permanent elongation, which is the elongation that does not return to the original state even when the load is removed from the toothed belt, cannot be sufficiently suppressed.

[0006] Furthermore, flexibility is also an important required property of a toothed belt, but the above-mentioned conventional techniques do not take into consideration the relationship between crosslinking by organic peroxides and improvement in flexibility.

[0007] An object of one aspect of the present invention is to provide a toothed belt which is suppressed in permanent set and has improved flexibility. [Means for solving the problem]

[0008] In order to solve the above problems, a toothed belt according to one embodiment of the present invention comprises a rubber layer having a tooth portion on at least one surface side, a plurality of core wires embedded in the rubber layer, an adhesive layer adhered to the surface side of the rubber layer where the tooth portion is provided, and an impregnation layer formed on the surface of the adhesive layer and in which rubber is impregnated into a raw canvas, wherein the adhesive layer contains an organic peroxide, the core wire contains a latex component therein, and the adhesion area between the core wire and the adhesive layer is 40% or more and 50% or less of the surface area of ​​the core wire.

[0009] According to the above configuration, when the latex component inside the core wire is crosslinked by the organic peroxide contained in the adhesive layer and the latex component is vulcanized, the latex component inside the core wire is appropriately hardened and becomes elastic. As a result, no plastic deformation occurs when stress is applied, and permanent set is reduced. Furthermore, since the adhesion area between the core wire and the adhesive layer is 40% or more and 50% or less of the surface area of ​​the core wire, the latex component is appropriately crosslinked and permanent set can be reduced.

[0010] The core wire may be formed by Lang twisting.

[0011] According to the above configuration, since the core wire is formed by Lang twisting, which has low bending rigidity, the flexibility of the toothed belt can be improved.

[0012] The number of twists of the core wire may be 0.5t / 25mm or more and 1.5t / 25mm or less.

[0013] According to the above configuration, the tensile rigidity, which is reduced due to the core wire being Lang-twisted, can be increased compared to the case where the core wire is ply-twisted. Effect of the Invention

[0014] According to one aspect of the present invention, it is possible to provide a toothed belt in which permanent set is suppressed and flexibility is improved. [Brief description of the drawings]

[0015] [Figure 1] 1 is a partially cutaway perspective view of a toothed belt according to an embodiment of the present invention. [Diagram 2] 2 is a perspective view of the toothed belt, with a part cut away, seen from a different direction than FIG. 1. [Diagram 3] FIG. 2 is a cross-sectional view in the width direction of the toothed belt. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Embodiment] Hereinafter, one embodiment of the present invention will be described in detail.

[0017] Fig. 1 is a partially cut-away perspective view of a toothed belt 1 according to this embodiment. Fig. 2 is a partially cut-away perspective view of the toothed belt 1 as seen from a different direction from that of Fig. 1. Fig. 3 is a cross-sectional view of the toothed belt 1 in the width direction.

[0018] 1 to 3, the toothed belt 1 is an endless belt that is stretched around a plurality of toothed pulleys. The toothed belt 1 includes a rubber main body 2 and a tooth cloth 3.

[0019] The rubber body 2 has a rubber layer 4 and a plurality of core wires 5 .

[0020] The rubber layer 4 has a back rubber portion 41 and a tooth rubber portion 42 (tooth portion). The rubber layer 4 is configured by integrally forming the back rubber portion 41 and the tooth rubber portion 42 from a rubber material having excellent abrasion resistance such as chloroprene rubber or high-strength synthetic rubber.

[0021] The back rubber part 41 constitutes the base part of the toothed belt 1 and is formed in a long belt shape. The back rubber part 41 has a tooth surface 41a as a surface that is hung on the toothed pulley. The toothed rubber parts 42 have a shape that meshes with the teeth of the toothed pulley and are formed at equal intervals on the tooth surface 41a side of the back rubber part 41. The toothed rubber parts 42 may be formed on both surfaces of the back rubber part 41. Therefore, the toothed rubber parts 42 are formed on at least one surface side of the back rubber part 41.

[0022] 3, the core wire 5 is embedded in the rubber layer 4 so that a part of the core wire 5 protrudes from the tooth surface 41a toward the tooth cloth 3. The core wire 5 is made of a synthetic fiber cord, a glass cord, a carbon fiber cord, or the like.

[0023] The synthetic cord is a cord in which a treatment liquid is impregnated into a multifilament yarn such as polyamide fiber, aramid fiber, or polyester fiber. The glass cord is a cord in which a treatment liquid is impregnated into a multifilament yarn such as E-glass fiber or high-strength glass fiber. The carbon fiber cord is a cord in which a treatment liquid is impregnated into a multifilament yarn of carbon fiber. An example of the treatment liquid is an RFL (resorcinol-formalin-latex) liquid containing a latex (L) component, which corresponds to the above-mentioned rubber material. In this way, the core wire 5 contains a latex component inside.

[0024] The core wire 5 is a cord formed by rung twisting the multifilament yarn impregnated with the above-mentioned treatment liquid in the Z direction or the S direction. The twist number of the treated yarn constituting the core wire 5 is 0.5t / 25mm or more and 1.5t / 25mm or less.

[0025] The tooth cloth 3 is formed so as to cover the tooth surface 41a and the surface of the tooth rubber portion 42. The tooth cloth 3 has an adhesive layer 31 and an impregnated layer 32.

[0026] The adhesive layer 31 is adhered to the tooth surface 41a side of the rubber layer 4. The adhesive layer 31 is a layer formed by applying a thin layer of rubber paste to the surface of the tooth cloth 3 that contacts the rubber layer 4. The adhesive layer 31 contains an organic peroxide as a cross-linking agent that cross-links the latex component of the core wire 5. As the organic peroxide contained in the adhesive layer 31, for example, Perbutyl (registered trademark) P-40 (α,α'-di(tri-t-butylperoxy)diisopropylbenzene) manufactured by NOF Corporation is preferably used, but is not limited to this organic peroxide. The adhesive layer 31 may also contain a cross-linking assistant in addition to the cross-linking agent.

[0027] In addition, other examples of the organic peroxide (crosslinking agent) that can be used include 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, n-butyl-4,4-di-t-butylperoxyvalerate, dicumyl peroxide, t-butyl peroxybenzoate, di-t-butylperoxy-diisopropylbenzene, t-butylcumyl peroxide, 2,5-dimethyl-2,5-t-butylperoxyhexane, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di-t-butylperoxyhexane-3.

[0028] Furthermore, examples of the crosslinking aid that can be used include tetrahydrofurfuryl methacrylate, ethylene dimethacrylate, 1,3 butylene dimethacrylate, 1,4 butylene dimethacrylate, 1,6 hexanediol dimethacrylate, polyethylene glycol dimethacrylate, 1,4 butanediol diacrylate, 1,6 hexanediol diacrylate, 2,2'bis(4-methacryloxydiethoxyphenyl)propane, 2,2'bis(4-acryloxydiethoxyphenyl)propane, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and pentaerythritol triacrylate.

[0029] The impregnated layer 32 is formed on the surface of the adhesive layer 31 and is in direct contact with the toothed pulley. The impregnated layer 32 is a layer impregnated with rubber by allowing rubber cement to soak into the raw canvas.

[0030] Here, most of the core wire 5 is embedded in the rubber layer 4, but as described above, a part of it protrudes toward the tooth cloth 3 side, and the protruding part is bonded to the adhesive layer 31. The bonding area between the core wire 5 and the adhesive layer 31 is preferably 40% or more and 50% or less of the surface area of ​​the core wire 5.

[0031] In such a structure, the latex component of the RFL liquid impregnated in the core wire 5 comes into contact with the organic peroxide contained in the adhesive layer 31 of the tooth cloth 3, and the latex component is crosslinked. This causes the latex component in the core wire 5 to harden appropriately and become elastic. This makes it less susceptible to plastic deformation when subjected to stress, and suppresses permanent set.

[0032] When the above-mentioned adhesive area is smaller than 40% of the surface area of ​​the core wire 5, for example, when the adhesive area is about 30% of the surface area of ​​the core wire 5, the latex component is not cured sufficiently, resulting in a large permanent elongation of the toothed belt 1. In addition, the adhesiveness between the core wire 5 and the tooth cloth 3 is reduced, so that the tooth cloth 3 is easily peeled off from the rubber layer 4 during use of the toothed belt 1.

[0033] If the above-mentioned adhesion area is greater than 50% of the surface area of ​​the core wire 5, the latex component is excessively cross-linked and hardened, resulting in a loss of flexibility, and as a result, the flex fatigue resistance of the toothed belt 1 decreases.

[0034] Furthermore, the core wires 5 are formed by Lang twisting. Lang twisting has low bending rigidity. Therefore, not only can the flexibility of the toothed belt 1 be improved, but also bending fatigue resistance can be improved.

[0035] Moreover, the twist number of the core wire 5 is 0.5t / 25mm or more and 1.5t / 25mm or less. The Lang twist of the core wire 5 reduces the tensile stiffness of the core wire 5. In contrast, by setting the twist number of the core wire 5 within the above range, the tensile stiffness can be increased compared to a multi-twist core wire with a twist number of 2.0t / 25mm.

[0036] [Additional Notes] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. In addition, embodiments obtained by appropriately combining the technical means disclosed in the respective embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0037] 1 Toothed belt 3 Tooth cloth 4 Rubber Layer 5 core wire 31 Adhesive layer 32 Impregnated layer 41a Tooth surface (surface) 42 Tooth rubber part (tooth part)

Claims

1. a rubber layer having teeth on at least one surface side; A plurality of core wires embedded in the rubber layer; The tooth cloth has an adhesive layer that is adhered to the surface side of the rubber layer on which the tooth portion is provided, and an impregnation layer that is formed on the surface of the adhesive layer and that impregnates the raw canvas with rubber, The adhesive layer contains an organic peroxide, the core wire is impregnated with a treatment liquid containing a latex component, the latex component of the treatment liquid impregnated into the core wire is crosslinked by the organic peroxide contained in the adhesive layer, A toothed belt, wherein an adhesion area between the core wire and the adhesive layer is 40% or more and 50% or less of a surface area of ​​the core wire.

2. 2. The toothed belt according to claim 1, wherein the core wire is formed by Lang twisting.

3. 3. The toothed belt according to claim 2, wherein the number of twists of the core wire is equal to or greater than 0.5t / 25mm and equal to or less than 1.5t / 25mm.

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