JP2011174593A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To fill rubber in clearances formed in a tooth cloth without deteriorating the strength of a toothed belt. <P>SOLUTION: This toothed belt 10 includes: a tooth rubber portion 11 formed in such a manner that teeth 14 and tooth bottoms 15 are alternately formed along a longitudinal direction on one surface and a first rubber composition is vulcanized; a tooth surface rubber layer 16 formed in such a manner that it is layered on the one surface of the tooth rubber portion 11 and a second rubber composition having a composition different from that of the first rubber composition is vulcanized; and a tooth cloth 20 provided to cover the tooth surface rubber layer 16. At least a part of the tooth surface rubber layer 16 is filled in the clearances formed in the tooth cloth 20 and exposed to the surface of the tooth cloth 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a toothed belt that is used in, for example, a high load environment and has a tooth surface rubber partly filled in a gap of a tooth cloth.

  2. Description of the Related Art Conventionally, a toothed belt in which a tooth surface is provided with tooth portions and tooth bottom portions alternately provided with a tooth cloth is widely known. In the toothed belt, the matrix rubber constituting the belt main body is filled with the eyes of the tooth cloth, and further, the matrix rubber filled with the eyes of the tooth cloth may be exposed on the surface of the tooth cloth (for example, Patent Document 1). reference).

  In such a toothed belt, the binding effect between the belt body and the tooth cloth is enhanced by the anchor effect of the matrix rubber filled in the eyes of the tooth cloth, and the peeling of the tooth cloth is prevented. Further, when the matrix rubber is exposed on the surface of the tooth cloth, the above-described binding force is further increased, and the friction coefficient between the tooth cloth and the toothed pulley is lowered, thereby reducing the meshing sound of the toothed belt. It becomes possible.

  In Patent Document 1, the direction in which the elongation of the tooth cloth is high coincides with the longitudinal direction of the belt, and the tooth cloth is not pre-formed before vulcanization molding. It is greatly stretched to form a tooth profile.

Japanese Patent Laid-Open No. 11-166596

  By the way, in order to fill the matrix rubber with the eye of the tooth cloth, it is necessary to lower the viscosity at the time of vulcanization molding of the matrix rubber or to use a tooth cloth with a large eye at the time of vulcanization molding. However, since matrix rubber with low viscosity is generally low in strength, a toothed belt molded using such rubber does not have sufficient durability because the strength of the belt body decreases. The problem occurs. Similarly, when the eyes of the tooth cloth are enlarged, the strength of the tooth cloth is lowered, resulting in problems such as insufficient durability.

  Furthermore, in the cited document 1, the tooth cloth is elongated in the belt longitudinal direction at the belt tooth portion at the time of belt molding, but is hardly elongated at the tooth bottom portion, so that the gap of the tooth cloth becomes uneven. Accordingly, the amount of rubber filled in the tooth gap and exposed to the outside becomes non-uniform, which contributes to a decrease in belt performance.

  The present invention has been made in view of the above problems, and provides a toothed belt that can be filled with rubber in the eyes of a tooth cloth without deteriorating belt performance such as durability. Objective.

  The toothed belt according to the present invention has a tooth rubber part formed by vulcanizing the first rubber composition, wherein tooth parts and tooth bottom parts are alternately provided on one surface along the longitudinal direction, and tooth rubber. And a tooth surface rubber layer formed by vulcanizing a second rubber composition having a composition different from that of the first rubber composition, and is provided so as to cover the tooth surface rubber layer. And at least a part of the tooth surface rubber layer is filled in a gap of the tooth cloth.

  The second rubber composition preferably has a lower viscosity than the first rubber composition. For example, the viscosity of the second rubber composition is 35000 Pa · s or less. Moreover, it is preferable that the clearance length of a tooth cloth is 60 micrometers or less, for example. Furthermore, the tooth surface rubber layer filled in the gaps of the tooth cloth should be exposed on the tooth cloth surface.

  The method for manufacturing a toothed belt according to the present invention includes a tooth cloth formed in a tooth shape, in which a plurality of tooth grooves are arranged in the circumferential direction and formed in a tooth shape, and a tooth cloth that is pre-formed so as to follow the tooth shape. And a tooth cloth attaching step for attaching the tooth surface rubber sheet formed along the tooth cloth so as to be arranged in this order, a core wire winding step for winding the core wire on the tooth surface rubber sheet, and a core wire Or between the core wire and the tooth surface rubber sheet, a composition different from that of the tooth surface rubber sheet, and a rubber sheet attaching step for further attaching a rubber sheet for forming a tooth portion of the belt, and a tooth surface rubber sheet and The rubber sheet is pressurized and heated toward the toothed mold to fill at least a part of the tooth surface rubber sheet in the gap of the tooth cloth, and the tooth surface rubber sheet and the rubber sheet are vulcanized to form a belt slab. Characterized in that it comprises obtaining a belt molding process.

  In the present invention, by providing the tooth surface rubber layer on the tooth rubber portion, it becomes possible to easily fill the eye with the tooth cloth without reducing the strength of the toothed belt. Further, in the belt manufacturing method of the present invention, the tooth cloth is hardly stretched by being pre-formed, and further, the tooth surface rubber sheet is vulcanized and molded in a state of being in close contact with the tooth cloth, so it is compared with the gap of the tooth cloth. The rubber can be filled uniformly and easily.

It is sectional drawing of the toothed belt which concerns on one Embodiment of this invention. It is sectional drawing which shows the process in which a tooth cloth is preformed. It is sectional drawing which shows the process in which the preformed tooth cloth with a rubber | gum is produced. It is sectional drawing which shows the process in which each belt material is attached to a toothed mold. It is sectional drawing which shows the process in which a belt slab is obtained by vulcanization molding. It is sectional drawing of the toothed belt which concerns on the modification of this invention. It is a schematic perspective view for showing the measuring method of adhesive strength.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a toothed belt according to an embodiment of the present invention. The toothed belt 10 is formed in an endless shape and is used by being driven around a driven pulley and a driving pulley (not shown). The torque (driving force) of the driving pulley is applied to the driven pulley by meshing transmission. This is a power transmission belt for transmission. The toothed belt 10 is a belt having one surface formed in a tooth shape, and a tooth surface formed in the tooth shape is covered with a canvas (tooth cloth) 20. The tooth surface is a surface (pulley contact surface) that contacts the driven and driving pulleys when the belt 10 is wound around the pulleys.

  The toothed belt 10 is wound in a spiral shape at a boundary portion between the belt main body 13 integrally formed by the tooth rubber portion 11 and the back rubber portion 12 and the tooth rubber portion 11 and the back rubber portion 12. And a core wire 30 extending in the longitudinal direction and embedded therein. That is, the tooth rubber part 11 is a layer arranged on the tooth surface side from the core wire 30, and the tooth parts 14 and the tooth bottom parts 15 are alternately formed on the one surface side along the longitudinal direction. On the surface of the tooth rubber portion 11 formed in a tooth shape by the tooth portion 14 and the tooth bottom portion 15, a thin tooth surface rubber layer 16 along the tooth shape is further laminated. The tooth cloth 20 covers the tooth surface rubber layer 16 while being at least partially embedded in the tooth surface rubber layer 16.

  The tooth cloth 20 is a woven fabric formed by weaving a first thread (for example, weft) extending along the longitudinal direction of the belt and a second thread (for example, warp) extending along the width of the belt. For example, it is woven by plain weave, twill weave, satin weave or the like. The first yarn is a composite yarn having elasticity, and is composed of a core yarn, an intermediate yarn wound around the core yarn, and a covering yarn wound further outside of the intermediate yarn. is there. The second yarn is a non-stretchable yarn made of a filament yarn, and is made of synthetic fiber such as polyurethane, nylon, carbon, polyester, polyethylene, etc., and preferably made of nylon.

  The core yarn of the first yarn is an elastic yarn, and is composed of synthetic fibers such as polyurethane, nylon, polyester, etc., and is preferably a polyurethane elastic yarn. The intermediate yarn is a non-stretchable yarn and is composed of, for example, a highly rigid fiber yarn such as an aramid fiber. On the other hand, the coated yarn is composed of synthetic fibers such as polyurethane, nylon, polyester, etc., and may be a stretchable yarn having elasticity by being crimped, or may be composed of natural fibers such as cotton. Good but preferably composed of crimped nylon. However, both the first and second yarns may be made of a non-stretchable yarn made of an aramid fiber filament yarn or the like.

  In the woven fabric, the length (that is, the gap length) of the gap between the yarns (between the warp and the warp and between the weft and the weft) (that is, the length of the tooth cloth 20) is 60 μm or less, preferably 30 μm. It is as follows. Thus, by shortening the gap length, the yarn density in the tooth cloth 20 can be increased, and the strength of the tooth cloth 20 can be improved. In the present specification, the gap length of the tooth cloth 20 refers to the gap length in the tooth cloth before molding (in this embodiment, the tooth cloth before preforming) before being bonded to the tooth surface rubber layer 16. That is, the gap between yarns was measured with an optical microscope. The tooth cloth 20 is usually subjected to an impregnation treatment such as an RFL treatment with an RFL treatment liquid or the like, but the gap between the yarns needs to be treated so as not to be clogged with the treatment agent.

  The rubber of the tooth surface rubber layer 16 is filled in the gaps (tooth cloth eyes) of the tooth cloth 20, and the rubber filled in the gaps of the tooth cloth 20 oozes out to the surface side of the tooth cloth 20. , Exposed on the surface of the tooth cloth 20.

  The tooth rubber part 11, the back rubber part 12, and the tooth surface rubber layer 16 are composed of a tooth rubber sheet 11 ′, a back rubber sheet 12 ′, and a tooth surface rubber sheet 16 ′ (FIG. 4) which are made of mutually different rubber compositions. Reference) is formed by vulcanization. However, the rubber composition for forming the back rubber part 12 may be the same as the rubber composition for forming the tooth rubber part 11. The rubber components of the tooth rubber part 11 and the back rubber part 12 include hydrogenated nitrile rubber (HNBR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), fluorine rubber, silicone rubber, Alternatively, a mixture thereof or the like is used, but rubber components other than fluorine rubber and silicone rubber are preferable.

  On the other hand, these rubber components are similarly used as the rubber component constituting the tooth surface rubber layer 16, but those having low friction such as fluoro rubber and silicone rubber are preferably used. That is, in this embodiment, the dynamic friction coefficient with respect to the rubber pulley (driven / driven pulley) forming the tooth surface rubber layer 16 is preferably lower than the rubber forming the tooth rubber portion 11 and the back rubber portion 12. Further, as the rubber component constituting the tooth surface rubber layer 16, fluorine rubber is particularly preferably used. This is because the use of fluororubber for the tooth surface rubber layer 16 improves the heat resistance of the tooth surface.

  In addition to the rubber component, the rubber composition for forming the back rubber portion 12, the tooth rubber portion 11, and the tooth surface rubber layer 16 includes a filler such as carbon black, a plasticizer, a vulcanization aid, and a vulcanization. Additives such as agents are blended.

  The viscosity of the rubber composition for forming the tooth surface rubber layer 16 is filled in the gaps of the tooth cloth 20 and can further ooze out from the tooth cloth surface. It is lower than the viscosity of the rubber composition for forming the (belt body 13), and is 35000 Pa · s or less, preferably 30000 Pa · s or less. The viscosity of the rubber composition can be adjusted, for example, by changing the molecular weight of the rubber component, whether or not a plasticizer is blended or blended, or the blending amount of the vulcanization aid.

  The viscosity of the rubber composition is a viscosity at 100 ° C., and the viscosity measurement is performed by a flow test. The formula for calculating the viscosity is as follows. In addition, the viscosity in this specification is a viscosity when the die length L is 2 mm and the diameter D of the die hole is 1 mm.

n = τ / γ [n: viscosity (Pa · s)]
τ = (P × D) / (4 × L)
[Τ: Apparent shear stress, P: Test pressure (0.980665 Mpa = 1 kgf / cm ² ), L: Die length (mm), D: Die hole diameter]
γ = (32 × Q) / (π × D × 3) [γ: shear rate]
Q = {A * (S2-S1)} / (10 * t)
[Q: flow rate, A: piston cross-sectional area (diameter 11.282 mm, S1: piston position at start of test, S2: piston position at end of test, t: elapsed time from start to end of piston)

  When the viscosity of the rubber composition of the tooth surface rubber layer 16 is 35000 Pa · s or less, for example, even when the tooth cloth 20 having a gap length of 60 μm or less is used, the tooth surface rubber layer 16 is formed in the gap of the tooth cloth 20. In addition, the filled rubber can be sufficiently oozed out of the surface of the tooth cloth 20 to be exposed. If the viscosity is 30000 Pa · s or less, even when the gap length is 30 μm or less, the tooth surface rubber layer 16 is filled in the gap of the tooth cloth 20, and the filled rubber is applied to the surface of the tooth cloth 20. It can be sufficiently exposed. Usually, in a toothed belt, a tooth cloth having a gap length of about 30 μm is used, so the viscosity is preferably 30000 Pa · s or less. The tooth surface rubber layer 16 has a lower modulus than that of the tooth rubber part 11 and the back rubber part 12 by using a rubber composition having a low viscosity.

  The rubber composition for forming the tooth rubber portion 11 preferably further includes short fibers made of nylon fibers such as modified nylon microfibers, aramid fibers, or the like. The modulus of the tooth rubber part 11 can be improved by mixing short fibers, and for example, the modulus of the tooth rubber part 11 is higher than that of the back rubber part 12.

  The modulus of each of the rubber parts 11 and 12 and the rubber layer 16 refers to a measurement sample obtained by vulcanizing an unvulcanized rubber sheet under the same temperature, pressure and time conditions as in the method for manufacturing a toothed belt. -It means 20% modulus measured according to K6251. When the short fibers are oriented in a predetermined direction in each of the rubber portions 11 and 12 and the rubber layer 16, the modulus means that the short fibers are oriented in one direction in the sample and the sample is oriented in the orientation direction. It is the value when measured by pulling.

  2-5 is a figure for demonstrating the manufacturing method of the toothed belt which concerns on this embodiment. In manufacturing the toothed belt 10, first, the preforming drum 51 is used to preform the tooth cloth 20, and the tooth surface rubber sheet 16 ′ and the tooth rubber sheet 11 ′ are attached to the tooth cloth 20.

  As shown in FIG. 2, tooth grooves 52 and convex portions 55 are alternately provided in the circumferential direction on the outer periphery of the preforming drum 51, and a toothed roller 53 is engaged with a part of the outer periphery. The toothed roller 53 is provided with a tooth portion 54 that cooperates with the tooth groove 52 of the preforming drum 51. The pre-forming drum 51 and the toothed roller 53 are rotated in directions indicated by arrows A and B, respectively.

  The tooth cloth 20 is supplied to the pre-forming drum 51 so as to surround a part of the outer periphery of the pre-forming drum 51 and is introduced into the engagement region with the toothed roller 53. The tooth cloth 20 is supplied along the direction that coincides with the longitudinal direction of the belt, that is, the direction in which the first yarn extends. The tooth cloth 20 is preformed into a corrugated shape in which the concave portions 20 </ b> A and the convex portions 20 </ b> B are alternately formed by the cooperative action of the convex portions 55 and the tooth portions 54.

  As shown in FIG. 3, a steel band 57 is caused to travel at the same speed as the peripheral speed of the preforming drum 51 with an appropriate pressing force on a part of the outer periphery of the preforming drum 51. Between the preforming drum 51 and the steel band 57, the tooth surface rubber sheet 16 'and the tooth rubber sheet 11' are superposed and supplied. In addition, the pre-formed tooth cloth 20 is also supplied to the lower side of the steel band 57 in a state of being wrapped around the outer periphery of the pre-forming drum 51.

  Between the preforming drum 51 and the steel band 57, the tooth surface rubber sheet 16 ′ and the tooth rubber sheet 11 ′ are laminated and integrated on the preformed tooth cloth 20 in this order from the tooth cloth 20 side. As a result, the pre-formed tooth cloth 50 with rubber in which the tooth surface rubber sheet 16 ′ and the tooth rubber sheet 11 ′ are joined to the tooth cloth 20 is obtained.

  By pressing the steel band 57, the tooth surface rubber sheet 16 ′ comes into close contact with the tooth cloth 20 and has a shape along the tooth cloth 20, and the tooth rubber sheet 11 ′ comes into close contact with the tooth surface rubber sheet 16 ′ and teeth. It becomes a shape along the surface rubber sheet 16 ′. Further, the rubber sheets 16 ′ and 11 ′ are deformed along the unevenness of the tooth cloth 20, and are relatively thick inside the concave portion 20 </ b> A and relatively thin on the convex portion 20 </ b> B. As a result, tooth portions 14 ′ and tooth bottom portions 15 ′ are alternately formed on the preformed tooth cloth 50.

  When the tooth cloth 20 is supplied to the preforming drum 51, the tension applied in the supply direction (that is, the direction in which the first yarn extends) is controlled, and the tension is substantially applied in the supply direction. Or the applied tension is relatively small. In addition, when the tooth cloth 20 or the rubber-made pre-formed tooth cloth 50 advances along the pre-forming drum 51 and is recovered from the pre-forming drum 51, the tension is not substantially applied in the same manner. Or the tension is reduced. That is, the tooth cloth 20 is supplied and advanced while being slackened so as not to be longer than the original length in the supply direction, for example, and further collected. Accordingly, the tooth cloth 20 is hardly stretched in the longitudinal direction of the belt in a process in which the tooth cloth 20 is preformed and the rubber sheet is closely adhered.

  After the rubber pre-formed tooth cloth 50 is sequentially cut to a predetermined length, as shown in FIG. 4, the pre-formed tooth cloth 50 is wound around the outer periphery of a cylindrical tooth mold 60 so that the tooth cloth 20 side faces inward. The toothed mold 60 is formed in a tooth shape by arranging a plurality of tooth grooves 61 at equal intervals in the circumferential direction on the outer peripheral surface thereof. Since the pre-formed tooth cloth 50 with rubber is pre-formed so as to follow the tooth profile of the toothed mold 60, when wound around the toothed mold 60, the tooth portion 14 ′ is disposed in the tooth groove 61. The tooth bottom portion 15 ′ is disposed on the convex portion 62 between the tooth spaces 61.

  Next, the core wire 30 is wound on the pre-formed tooth cloth 50 with rubber (that is, the tooth rubber sheet 11 ′) in a spiral shape along the circumferential direction so that the adjacent core wires 30 have a predetermined gap therebetween. It is done. Next, the back rubber sheet 12 ′ is further wound around the core wire 30.

  The toothed mold 60 to which these rubber sheets and the like are attached is accommodated in a vulcanizer (not shown). The inside of the vulcanizer is maintained at a predetermined temperature by, for example, steam, and pressure is urged from the outer peripheral side toward the mold 60 by a vulcanization bag or the like provided in the vulcanizer, so that the belt Is vulcanized. The temperature in the vulcanizing pot at the time of vulcanization molding is 150 ° C. or higher, preferably 160 ° C. or higher, and the pressure applied by the vulcanization bag is 800 kPa or higher, preferably 1000 kPa or higher.

  The vulcanization molding will be described in detail. The rubber sheets 16 ′, 11 ′, 12 ′ whose fluidity has been increased by heating are pressed inward, and the tooth cloth 20 pressed by these rubber sheets is the outer periphery of the mold 60. The shape matches the surface. At this time, since the tooth cloth 20 is pre-shaped in a corrugated shape, it is not stretched so much in the longitudinal direction of the belt.

  The tooth surface rubber sheet 16 ′ has a relatively low viscosity (for example, 35000 Pa · s or less), and the fluidity is sufficiently high due to the above heating and pressurizing conditions. ) And ooze out to the surface of the tooth cloth 20. Therefore, in this embodiment, a part of the tooth surface rubber sheet 16 ′ is filled in the gaps of the tooth cloth 20 and is exposed on the surface of the tooth cloth 20. Further, the rubber sheets 16 ', 11' and 12 'are vulcanized and integrated, and a core wire is embedded between the rubber sheets 11' and 12 'to form a belt slab 10'. The belt slab 10 ′ is removed from the toothed mold 60 and cut after polishing to become the toothed belt 10 (see FIG. 1).

  In the present embodiment, the tooth rubber sheet 11 ′ is not attached in advance to the pre-formed tooth cloth 50 with rubber. For example, after the core wire 30 is attached on the pre-formed tooth cloth 50 with rubber, the core wire 30. It may be wrapped around. However, the tooth rubber sheet 11 ′ is preferably attached to the pre-formed tooth cloth 50 with rubber as described above.

  As shown in FIG. 6, an adhesive rubber portion 19 in which the core wire 30 is embedded may be provided between the tooth rubber portion 11 and the back rubber portion 12. The rubber composition for forming the adhesive rubber part 19 is preferably different from the rubber composition for forming the tooth rubber part 11, the back rubber part 12, and the tooth surface rubber layer 16. For example, the adhesive rubber part 19 has a higher modulus than the tooth rubber part 11, the back rubber part 12, and the tooth surface rubber layer 16. For example, the viscosity of the rubber composition for forming the adhesive rubber part 19 is higher than the viscosity of the rubber composition of the tooth surface rubber layer 16. When the adhesive rubber portion 19 is provided, the manufacturing method of the toothed belt is the same as the manufacturing method described above except that the adhesive rubber sheet is attached on the core wire 30.

  The core wire 30 is not completely embedded in the adhesive rubber portion 19, and most of the adhesive rubber portion 19 is more than the core wire 30 as disclosed in, for example, JP 2009-127816 A. While being arrange | positioned at the tooth | gear surface side, the one part may protrude and be formed in the back rubber part 12 side. In this case, the manufacturing method of the toothed belt is the same as the manufacturing method described above, except that the adhesive rubber sheet is attached between the core wire 30 and the tooth rubber sheet 14 '. Of course, the adhesive rubber portion may not be provided, and a part of the tooth rubber portion 11 may be formed to protrude from the back rubber portion 12 side.

  As described above, in the present embodiment, the rubber constituting the belt main body 13 (particularly, the tooth rubber portion 11) is used as the rubber that fills the tooth cloth 20 and is partially exposed on the surface of the tooth cloth 20. A tooth surface rubber layer 16 having a different composition is provided. Therefore, it is possible to use rubber having a low viscosity and easily filling and leaching into the tooth cloth 20 while using high-strength rubber for the belt body 13. Therefore, it is possible to reduce the friction coefficient of the tooth surface and improve the adhesive strength of the tooth cloth while maintaining the strength of the belt main body 13. Further, since the tooth surface rubber layer 16 is formed as a thin layer, even if rubber having low viscosity and low strength is used, the belt strength is hardly lowered.

  Moreover, in this embodiment, since the tooth cloth 20 is preformed as described above, it is suppressed from extending in the belt longitudinal direction in the belt manufacturing process. Therefore, it is possible to prevent the gap of the tooth cloth 20 from changing in the manufacturing process, and to make the gap of the tooth cloth 20 substantially uniform over the entire surface of the tooth cloth 20. Therefore, the rubber of the tooth surface rubber sheet 16 ′ is uniformly filled in the gaps, and the rubber oozes out to the tooth cloth surface uniformly over the entire tooth surface. Further, since the tooth surface rubber sheet 16 ′ is pressurized and heated from the state of being in close contact with the tooth cloth 20, it is easy to control the amount of rubber filled in the gaps of the tooth cloth 20.

  Examples are shown below as specific examples of the present invention, but the present invention is not limited to the following examples.

[Leakage evaluation]
The rubber components are fluororubbers, and have a rubber composition as shown in Table 1. Each of the unvulcanized rubbers 1 to 5 having a thickness of 3 mm, a length of 120 mm, and a width of 120 mm has different gap lengths. Each of 7 was vulcanized and bonded by press heating to produce a vulcanized rubber with a tooth cloth. The pressing conditions were a temperature of 160 ° C., a pressure of 1000 kPa, and a pressing time of 20 minutes. In each vulcanized rubber with tooth cloth, whether or not the gap between the tooth cloths was filled with rubber and the rubber oozed out on the tooth cloth surface was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 2.

  The unvulcanized rubbers 1 to 5 have viscosities as shown in Tables 1 and 2, and the tooth cloths 1 to 7 include warps made of filament yarns of aramid fibers and weft yarns made of filament yarns of aramid fibers. A woven fabric woven with plain weave was used. Table 3 shows the thread thickness and density of each tooth cloth. The tooth cloths 1 to 7 were subjected to RFL treatment by dipping in an RFL liquid whose latex is NBR and then drying.

[Evaluation criteria]
○: Exudation of rubber was observed on almost the entire surface of the tooth cloth.
(Triangle | delta): The oozing-out of rubber | gum was seen in a part of tooth | gear surface.
X: No oozing of rubber was observed on the tooth cloth surface.

※表１において、粘度以外の数値は、重量部を示す。また、“−”は未配合であることを示す。

* In Table 1, numerical values other than viscosity indicate parts by weight. Further, “-” indicates that it is not blended.

※表２において、ゴム１〜５の（）内は未加硫ゴムの粘度を表すとともに、歯布１〜７の（）内は歯布の隙間長さを表す。表２において、粘度の単位は、Ｐａ・ｓであるとともに、隙間長さの単位はμｍである。

* In Table 2, () in rubbers 1 to 5 represents the viscosity of unvulcanized rubber, and () in tooth fabrics 1 to 7 represents the gap length of the tooth fabric. In Table 2, the unit of viscosity is Pa · s, and the unit of gap length is μm.

  Next, as shown in Table 4, the tooth cloth 3 (gap length 30 μm) was pressed to each of the unvulcanized rubbers 2 and 3 in the same manner except that the temperature and pressure conditions during pressing were changed. Vulcanized rubber with a tooth cloth was produced by vulcanization and adhesion by heating, and leaching was evaluated according to the above evaluation criteria. The evaluation results are shown in Table 4.

[Tear strength]
As Examples 1 to 3, unvulcanized rubbers 5, 4, and 3 were each singly heated at a temperature of 160 ° C., a pressure of 1000 kPa, and a press time of 20 minutes to produce vulcanized rubbers. Further, as Comparative Examples 1 and 2, vulcanized rubbers were similarly prepared using the conventional rubber and the rubber 1, respectively. Conventional rubber used HNBR with a hydrogenation rate of 96% as a rubber component. The tear strength was measured in accordance with JIS K6252, and the “no cut angle type test piece” was used as the test piece.

[Adhesive strength]
As Examples 1 to 3, toothed cloth 3 (gap length 30 μm) is stacked on each of the sheet-like unvulcanized rubbers 5, 4, and 3, and these are vulcanized and bonded by press heating to vulcanize with toothed cloth. A rubber was prepared. The press heating conditions were a temperature of 160 ° C., a pressure of 1000 kPa, and a press time of 20 minutes. Further, as Comparative Examples 1 and 2, vulcanized rubbers with tooth cloths produced in the same manner using conventional rubber and rubber 1 were produced. For these vulcanized rubber with tooth cloth of Examples 1 to 3 and Comparative Examples 1 and 2, the adhesive strength was measured as follows.

  As shown in FIG. 7, in the vulcanized rubber 150 with the tooth cloth, the tooth cloth 152 and the rubber sheet 151 are slightly peeled off, the end portion of the tooth cloth 152 is sandwiched by the chuck 161, and the end portion of the rubber sheet 151 is sandwiched by the chuck 162. They were sandwiched and pulled at a speed of 50 mm / min to peel them off. The force required for peeling at this time was defined as adhesive strength.

Table 5 shows the results of adhesive strength and tear strength for each of the examples and comparative examples. In Table 5, the results of the rubber exudation evaluation described above are also shown.

  As is clear from the results of the seepage evaluation test, when the tooth cloth 3 having a gap length of 30 μm, which is usually used for toothed belts, is used, the surface of the tooth cloth is reduced by setting the viscosity of the rubber to 30000 Pa · s or less. It has become possible to ooze rubber on almost the entire surface.

  As is clear from the results of tear strength and adhesive strength, Examples 1 to 3 had tear strengths equal to or lower than those of Comparative Examples 1 and 2, but rubber was used in the gaps of the tooth cloth. The adhesive strength between the tooth cloth and the rubber sheet could be remarkably improved as compared with Comparative Examples 1 and 2 by filling the rubber and leaching rubber on the tooth cloth surface.

DESCRIPTION OF SYMBOLS 10 Toothed belt 11 Tooth rubber part 12 Back rubber part 16 Tooth surface rubber layer 20 Tooth cloth

Claims (6)

Tooth rubber portions formed by alternately providing tooth portions and tooth bottom portions along the longitudinal direction on one surface, and vulcanizing the first rubber composition;
A tooth surface rubber layer formed by vulcanizing a second rubber composition laminated on one surface of the tooth rubber part and having a composition different from that of the first rubber composition;
A tooth cloth provided so as to cover the tooth surface rubber layer,
At least a part of the tooth surface rubber layer is filled in a gap between the tooth cloths.   The toothed belt according to claim 1, wherein the second rubber composition has a lower viscosity than the first rubber composition.   The toothed belt according to claim 1 or 2, wherein the viscosity of the second rubber composition is 35000 Pa · s or less.   The toothed belt according to any one of claims 1 to 3, wherein the tooth surface rubber layer filled in a gap between the tooth cloths is exposed on the tooth cloth surface.   The toothed belt according to any one of claims 1 to 4, wherein a gap length of the tooth cloth is 60 µm or less. A plurality of tooth gaps are arranged in the circumferential direction, and a toothed mold formed in a tooth profile is formed in advance so as to follow the tooth profile, and to be in close contact with the tooth cloth and along the tooth fabric. A tooth cloth attaching step for attaching the tooth surface rubber sheets to be arranged in this order;
A core winding process of winding a core on the tooth surface rubber sheet;
A rubber sheet attaching step for further attaching a rubber sheet for forming a tooth portion of a belt, the composition being different from that of the tooth surface rubber sheet, or between the core wire and the tooth surface rubber sheet.
The tooth surface rubber sheet and the rubber sheet are pressurized and heated toward the toothed mold to fill at least a part of the tooth surface rubber sheet in the gap of the tooth cloth, and the tooth surface rubber And a belt molding step of obtaining a belt slab by vulcanizing the sheet and the rubber sheet.

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