JP2006022917A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent tooth missing of a toothed belt for a long time even in an use state where the oil is attached at a high temperature. <P>SOLUTION: This toothed belt 10 comprises a main body rubber layer 12 and canvas 11. The main body rubber layer 12 comprises tooth parts 14 and bottom parts 15 alternately arranged in the longitudinal direction on its one face. Outer surfaces of the tooth parts 14 and the bottom parts 15 are covered by canvas 11 and adhered. The canvas 11 is prepared by making a canvas main body 17 be impregnated with surface rubber 18 composed of fluorine rubber. An internal addition type adhesive is added to the surface rubber 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a toothed belt used in, for example, an internal combustion engine.

  A toothed belt used in an internal combustion engine or the like becomes unusable when a load is applied to the tooth base of the tooth portion and tooth missing occurs. Therefore, the surface having the tooth portion is covered with a canvas using an aramid fiber or the like in order to increase the strength against tooth chipping. However, the canvas contacts the pulley and wears out. When the fiber portion of the canvas directly contacts the pulley, it is worn out quickly due to wear, and it is difficult to provide durability against tooth chipping for a long time. Therefore, the surface of the canvas is covered with a treatment agent by RFL treatment or the like, or a rubber paste is impregnated and the surface is covered with a rubber composition to prevent the fiber portion of the canvas from directly contacting the pulley.

  On the other hand, since toothed belts used in recent internal combustion engines and the like are used in a situation where oil adheres in a high temperature atmosphere, the treatment agent and the rubber composition on the canvas surface deteriorate. The treated agent or rubber composition after deterioration wears out early in contact with the pulley and exposes the fiber portion of the canvas. As a result, the exposed fiber portion of the canvas is worn away by abrasion with the pulley, and it is difficult to maintain durability against tooth chipping for a long time.

Therefore, a toothed belt (see Patent Document 1) in which the entire belt including the surface of the canvas is made of fluorine rubber having high heat resistance and oil resistance (see Patent Document 1) and a toothed belt using a canvas impregnated with rubber mixed with fluorine rubber ( Patent Document 2) has been proposed. However, manufacturing costs increase by using fluororubber for the entire belt. Further, the heat resistance and oil resistance required for the toothed belt in the future are higher than the heat resistance and oil resistance of the toothed belt using the canvas using rubber mixed with fluoro rubber.
Japanese Patent Laid-Open No. 11-166596 JP 2000-240730 A

  Accordingly, an object of the present invention is to provide a toothed belt capable of suppressing generation of chipping for a long period of time even when used in a situation where oil adheres at a high temperature without extremely increasing the manufacturing cost. Is.

  The toothed belt according to the present invention includes a main body rubber layer in which tooth portions and tooth bottom portions are alternately formed along the longitudinal direction of the tooth surface, which is one surface, and a surface rubber that is provided on the tooth surface and is a fluoro rubber. And a covered canvas.

  It is preferable to impregnate the canvas with surface rubber, and it is preferable to add an internal adhesive to the surface rubber. The resin adhesive is at least one of resin-based maleic anhydride-modified liquid polybutadiene, maleic acid-modified liquid polybutadiene, acrylic acid-modified liquid polybutadiene, urethane-modified liquid polybutadiene, carboxylic-modified liquid polybutadiene, and maleic acid-modified liquid polyisoprene. It is preferable to use as a component. Furthermore, it is preferable that 4 to 24 parts by weight of a resin adhesive is added to the surface rubber with respect to 100 parts by weight of the fluororubber of the surface rubber.

  According to the present invention, it is possible to prevent the toothed belt from being chipped in a use situation under a high temperature where the lubricating oil adheres, and to be used for a long period of time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a side sectional view of a toothed belt 10 to which an embodiment of the present invention is applied. The toothed belt 10 includes a canvas 11 and a main rubber layer 12. The main rubber layer 12 is mainly composed of vulcanized rubber whose rubber component is H-NBR, for example.

  On one surface serving as the tooth surface 13 of the main rubber layer 12, tooth portions 14 and tooth bottom portions 15 are alternately and integrally formed along the longitudinal direction. The tooth surface 13 of the main rubber layer 12, that is, the outer surfaces of the tooth portion 14 and the tooth bottom portion 15 are covered with the canvas 11 and bonded. In the main rubber layer 12, core wires 16 extending in the longitudinal direction are embedded so as to be separated from each other.

  The canvas 11 is formed by impregnating a canvas body 17 woven using fibers such as aramid fiber with rubber glue obtained by dissolving fluororubber with a solvent such as methyl ethyl ketone, and the surface thereof is covered with a surface rubber 18 which is fluororubber. The Therefore, the surface rubber 18 and the main rubber layer 12 form an interface in the adhesion between the canvas 11 and the main rubber layer 12.

  An internally added adhesive is added to the surface rubber 18 to be impregnated into the canvas body 17. The internally added adhesive is, for example, a resin-based adhesive, preferably maleic acid-modified liquid polybutadiene. In the case of maleic acid-modified liquid polybutadiene, the amount of the internally added adhesive is preferably 4 to 24 parts by weight with respect to 100 parts by weight of the fluororubber component of the surface rubber 18.

  The adhesive strength between the fluorocarbon rubber and the canvas main body 17 using aramid fibers conventionally used, and between the fluororubber and H-NBR used for the main rubber layer 12, for example, is a conventional RFL treatment agent and others. Low compared to other rubber. Therefore, when the tooth portion 14 is deformed by meshing with the pulley and receiving a load, a tensile force is applied to the periphery of the tooth bottom portion 15 and the tooth root portion 19 of the canvas 11, and the canvas 11 may be peeled off from the main rubber layer 12. is there.

  However, by using an internally added adhesive mainly composed of maleic acid-modified liquid polybutadiene, the adhesive strength between the fluororubber and the canvas body 17, and the fluororubber and a rubber other than fluororubber such as H-NBR can be increased. . A toothed belt formed by adding 4 parts by weight or more of an internal adhesive with respect to 100 parts by weight of the fluororubber component has sufficient adhesive strength to be applied to the inside of an engine that is assumed to be used.

  On the other hand, when a large amount of internally added adhesive is added, the tensile stress of the canvas 11 is reduced, and the strength of the toothed belt 10 with respect to chipping is also reduced accordingly. A toothed belt formed by adding 24 parts by weight or less of an internally added adhesive to 100 parts by weight of the fluororubber component has a sufficient tensile stress to be applied to the engine intended for use.

  The toothed belt 10 is provided inside the engine, and the lubricating oil adheres to the entire toothed belt 10. The fluororubber used for the surface rubber 18 has high heat resistance and oil resistance, and in a use situation where the lubricating oil adheres inside the engine that is at a high temperature, the canvas body 17 is prevented from being exposed due to wear of the surface rubber 18 for a long period of time. . Therefore, tooth missing caused by the tearing of the canvas body 17 can be suppressed for a long period of time.

  As described above, according to the toothed belt 10 of the present embodiment, it is possible to prevent the occurrence of missing teeth for a long period of time in a usage situation where high-temperature lubricating oil adheres in the engine. Further, since high-cost fluororubber is used only on the surface of the canvas, a toothed belt having high heat resistance and oil resistance as described above and having reduced manufacturing costs can be obtained.

  Next, a process for manufacturing the toothed belt 10 to which the present embodiment is applied will be described. First, as shown in FIG. 2, the toothed belt molding drum 30 sequentially has a canvas material 20 that becomes the canvas 11 of the toothed belt 10, a cord 21 that becomes the core 16 of the toothed belt 10, and a toothed belt. A compounded rubber sheet 22 to be the main rubber layer 12 is wound.

  Thereafter, the belt-shaped drum 30 having a toothed belt around which the canvas material 20, the core cord 21, and the compounded rubber sheet 22 are wound is placed in a vulcanizing oven (not shown) where a predetermined temperature and a predetermined pressure are provided. Under vulcanization treatment.

  By the vulcanization treatment under a predetermined pressure, the tooth portion 14 is formed in the cylindrical intermediate product along the outer peripheral shape of the toothed belt molding drum 30. The compound rubber sheet 22 flows between the canvas material 20 and the core cord 21 from the gap between the core cord 21 adjacent to the core cord 21 to form the tooth portion 14. At the same time, the gaps between the canvas material 20, the core cord 21 and the compounded rubber sheet 22 are removed by vulcanization. The toothed belt 10 is obtained by cutting the cylindrical intermediate product thus obtained to an appropriate width.

  In this embodiment, maleic acid-modified liquid polybutadiene is added as an adhesive, but maleic anhydride-modified liquid polybutadiene, acrylic acid-modified liquid polybutadiene, urethane-modified liquid polybutadiene, carboxyl-modified liquid polybutadiene, and maleic acid-modified liquid polyisoprene. The effect similar to this embodiment can be obtained by using at least one of the above.

  In the present embodiment, the main rubber layer may be mainly composed of NBR, EPDM, CR, SBR, ACSM, polyurethane, or fluorine rubber. The main component of the main rubber layer is not limited to these rubbers.

  In this embodiment, the solvent for adjusting the rubber paste impregnated in the canvas body 17 may be xylene, toluene, ethyl acetate, trichlene, methyl chloride, or benzene. In addition, the solvent used for adjustment is not restricted to these solvents.

  Hereinafter, the present invention will be described with reference to FIGS. In addition, this invention is not limited at all by these Examples.

  [Rubber compounding] As shown in Tables 1 to 3 below, eight kinds of compounded rubber A to compounded rubber H to be used for preparation of sample pieces for the adhesive strength test and tensile test and for the production of toothed belts. And adjusting the RFL treatment agent.

In Table 1 above, * 1 and * 2 indicate the following items.
* 1 Product name of Nippon Zeon Co., Ltd., ethylenically unsaturated nitrile-conjugated diene-based highly saturated polymerized rubber.
* 2 Type of compounding material and parts by weight of compounding material relative to 100 parts by weight of rubber component (unit: phr).
Moreover, --- in a table | surface shows unblending.

In Table 2 above, * 1 to * 3 indicate the following items.
* 1 Du Pont's trade name, vinylidene fluoride-4 fluoroethylene-perfluoromethyl vinyl ether copolymer rubber.
* 2 Ricobond1731HS, trade name of RICON RESINS, maleic acid-modified liquid polybutadiene.
* 3 Type of compounding material and parts by weight of compounding material relative to 100 parts by weight of rubber component (unit: phr).
Moreover, --- in a table | surface shows unblending.

In Table 3 above, * 1 indicates the following items.
* 1 Type and weight percentage of blended raw materials (unit: wt%).

  Next, a sample for adhesion strength test using the above-described compounded rubber sheet A, which is H-NBR, and a canvas impregnated with a rubber paste selected from one of compounded rubber C to compounded rubber H, which is fluororubber. A piece was prepared, and an adhesive strength test between H-NBR and a canvas impregnated with rubber paste as fluororubber was performed using each sample piece.

  [Sample Piece for Adhesive Strength Test] As an example of producing the sample piece, a method for producing the example sample piece 1 will be described. First, a solvent in which methyl ethyl ketone and xylene were mixed at a ratio of 17: 1 was prepared. Next, compounded rubber D whose rubber component is fluororubber was dissolved in this solvent to prepare a rubber paste. The blending ratio of the blended rubber D and this solvent was 1: 3. Then, a rubber paste was impregnated into the fibrous main body of the canvas to obtain a processed canvas D '.

  Next, a compounded rubber sheet A having a thickness of over 4 mm, in which the main component of the rubber component is H-NBR, was prepared, and the treated canvas D 'was overlaid thereon, followed by press vulcanization. The press vulcanization was performed at a temperature of 170 ° C. for 20 minutes under a pressure of 4.9 MPa. Here, a part of one end was sandwiched with a tape before pressing in order to prevent vulcanization adhesion. The rubber plate thus bonded was cut out to a width of 25 mm and a length of 105 mm, thereby obtaining a sample piece, that is, an example sample piece 1.

  Example sample piece 2, Example sample piece 3, Example sample piece 4, Example sample piece 5, and Comparative example sample piece 1 are compounded rubber E, compounded rubber F, compounded rubber G, instead of compounded rubber D, respectively. The configuration and treatment other than the use of compounded rubber H and compounded rubber C were the same as those of Example Sample Piece 1.

  [Adhesive Strength Test and Evaluation] FIG. 3 shows a state in which the sample piece 23 is attached to a tensile tester (manufactured by Shimadzu Corporation, trade name: Shimadzu Autograph AGS-500D). The test method will be described with reference to FIG. The end portion of the rubber sheet 24 and the end portion of the canvas 25, which were protected from vulcanization by tape at one end of the sample piece 23, were respectively attached to the chuck 31 and pulled at a speed of 50 mm per minute by a tensile tester. Other experimental conditions were the same as JIS (K6256). The adhesive force was evaluated by measuring the peeling force between the rubber sheet 24, which is H-NBR, and the canvas 25. Table 4 shows the measurement results.

In Table 4 above, * 1 indicates the following items.
* 1 Ratio B / A of the adhesive strength of each example sample piece to the adhesive strength of the comparative sample piece 1 (A: adhesive strength of comparative sample piece 1, B: adhesive strength of example sample pieces 1-5).

  As can be seen from Table 4, the example sample piece 1 to the example sample piece 5 have a larger adhesive force than the comparative example sample piece 1. Conventionally used belts, for example, a belt in which a main body rubber layer mainly composed of H-NBR is bonded with a canvas subjected to RFL treatment are approximately 1.2 times or more in comparison with the adhesive strength of the comparative sample piece. The main rubber layer and the canvas are bonded with adhesive strength. From this result, in order to obtain an adhesive strength equal to or higher than that of a conventionally used belt, it is understood that a preferable result is obtained by adding 4 parts by weight or more of an adhesive to 100 parts by weight of the fluororubber component. .

  Next, using a canvas impregnated with a rubber paste selected from one of the above-mentioned blended rubber C to blended rubber H, which is a fluororubber, sample pieces for a tensile test are prepared, and each sample piece is used, A tensile test of the canvas was performed.

  [Sample Piece for Tensile Test] A method for producing the example sample piece 6 will be described as an example of producing the sample piece. First, the same treated canvas as that at the time of preparing a sample piece for an adhesive strength test using the compounded rubber C was prepared. That is, treated canvas C 'was obtained by using compounded rubber C instead of compounded rubber D.

  The treated canvas C ′ was cut out to a width of 25 mm and a length of 550 mm, and press vulcanized. The press vulcanization was performed at a temperature of 170 ° C. for 20 minutes under a pressure of 4.9 MPa. Example sample pieces 6 were obtained by drawing white lines at 100 mm intervals near the center of the canvas subjected to press vulcanization.

  Example sample piece 7, Example sample piece 8, Example sample piece 9, Example sample piece 10, and Example sample piece 11 are compounded rubber D, compounded rubber E, compounded rubber F, The configuration and treatment other than using the compounded rubber G and the compounded rubber H were the same as those of the example sample piece 6.

  [Tensile Test and Evaluation] FIG. 4 shows a state in which the canvas 26 to be tested is attached to a tensile tester (manufactured by Shimadzu Corporation, trade name: Shimadzu Autograph AGS-500D). The test method will be described with reference to FIG. Both ends of the canvas 26 were attached to the chucks 32 and 32, and pulled by a tensile tester at a speed of 150 mm per minute. Other experimental conditions were the same as JIS (L1096).

  The tensile stress was measured when the canvas 26 was stretched 20%, that is, when the distance between the white lines 27 and 27 drawn on the canvas 26 was 120 mm. It should be noted that by comparing the tensile stress with the canvas 26 stretched by 20% as a reference, the amount of adhesive added to obtain a canvas having a tensile stress equal to or higher than that of a conventionally used canvas can be estimated. . Table 5 shows the measurement results.

In Table 5 above, * 1 indicates the following items.
* 1 Ratio B / A of tensile stress at 20% elongation of Example Sample Piece 7 to Example Sample Piece 11 with respect to tensile stress at 20% elongation of Example Sample Piece 6 (A: Tensile Stress of Example Sample Piece 6 Stress, B: Tensile stress of Example sample pieces 7-11.

  The tensile stress of the canvas increases as the addition amount of the adhesive increases, and decreases when the addition amount exceeds 9 parts by weight. The canvas conventionally used for the toothed belt has a tensile stress of about 1.4 times or more compared with the tensile stress of the sample piece 6 of the embodiment. Therefore, it can be seen that a preferable result can be obtained by adding 24 parts by weight or less of an adhesive to 100 parts by weight of the fluororubber component in order to obtain a tensile stress equivalent to or higher than that of a conventionally used belt.

  Next, blend rubber B which is H-NBR as described above for the main rubber layer and aramid canvas in which the canvas is treated with the RFL treatment liquid shown in Table 3 or aramid canvas impregnated with rubber paste in which compound rubber G is dissolved in a solvent are used. Thus, toothed belts for running tests were manufactured, and running tests were performed using the respective toothed belts.

  That is, in the running test, a change in durability against tooth chipping of a toothed belt provided with a canvas impregnated with fluororubber paste instead of the RFL-treated canvas is observed. The solvent was prepared by mixing methyl ethyl ketone and xylene at a ratio of 17: 1, and the rubber paste was prepared by mixing compounded rubber G and the solvent at a ratio of 1: 3 and dissolving them.

  [Toothed belt for running test] The toothed belt was manufactured in accordance with the above-described toothed belt manufacturing method. Table 6 shows compounded rubbers used as raw materials for Examples and Comparative Examples.

In Table 6 above, * 1 indicates the following items.
* 1 Ratio of travel time of the toothed belt 1 of the embodiment to the travel time of the toothed belt 1 of the comparative example B / A (A: travel time of the toothed belt 1 of the comparative example, B: toothed belt of the embodiment 1 travel time).

  [Running Test and its Evaluation] FIG. 5 is a diagram showing a schematic configuration of a running test in a use situation where oil using an engine adheres. The travel test apparatus 33 includes a box-shaped housing 34 and a heater (not shown). A toothed pulley 35, a toothed pulley 36, and a tensioner 37 are provided between these pulleys in the housing 34. The heater is outside the housing 34 and close to the front wall portion facing the toothed pulley 35 and the toothed pulley 36.

  In the rear wall portion 34a of the housing 34, a shaft hole 38 is formed on the upper side, a shaft hole 39 is formed on the lower side, and a lubricating oil inflow hole 40 is formed therebetween. The toothed pulley 35 and the toothed pulley 36 are rotatably supported by a camshaft 41 and a crankshaft 42 inserted into the shaft hole 38 and the shaft hole 39, respectively. A tensioner 37 is provided obliquely below the toothed pulley 35.

  A toothed belt 28 to be tested is stretched around a toothed pulley 35, a toothed pulley 36, and a tensioner 37. The crankshaft 42 is connected to a motor (not shown) provided on the back side of the rear wall portion 34 a of the housing 34. At this time, the toothed belt 28 is bridged in such a manner that a strong load is applied to the tooth portion so that the toothed belt 28 to be tested is damaged due to missing teeth.

  Lubricating oil is supplied to the camshaft 41 from the back side of the rear wall portion 34a of the housing 34 using an oil pump (not shown). Lubricating oil flows along the camshaft 41 and the rear surface of the rear wall portion 34 a of the housing 34, and flows into the housing 34 from the shaft hole 38 and the lubricating oil inflow hole 40.

  A running test was performed by keeping the inside of the housing 34 at 120 ° C. with a heater and rotating the crankshaft 42 at 6000 rpm. The running time until the belt 28 with the tooth under test was damaged and the belt could not run was measured as a test result. Table 6 shows the measurement results.

  The toothed belt 1 of the comparative example was not able to run due to tooth missing after a certain period of time. In the toothed belt 1 of the example, tooth missing occurred when 1.7 times the time of the running time of the toothed belt of the comparative example passed. As described above, according to the toothed belt of the example, the occurrence of missing teeth can be suppressed longer than the toothed belt of the comparative example. As described above, since the deterioration of the surface rubber is suppressed, the exposure of the canvas main body is prevented for a long period of time. As a result, it is considered that the durability against the chipping caused by the tearing of the canvas main body is increased.

The side sectional view of the toothed belt to which one embodiment of the present invention is applied is shown. It is a schematic process drawing which shows the manufacturing process of a toothed belt. The schematic diagram of an adhesive strength test is shown. The schematic diagram of a tension test is shown. A schematic diagram of a running test is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Toothed belt 11 Canvas 12 Main body rubber layer 13 Tooth surface 14 Tooth part 15 Tooth bottom part 16 Core wire 17 Canvas main body 18 Surface rubber

Claims (6)

  A main body rubber layer in which tooth portions and tooth bottom portions are alternately formed along the longitudinal direction of the tooth surface that is one surface, and a canvas that is provided on the tooth surface and is covered with a surface rubber that is fluororubber. A toothed belt characterized by that.   The toothed belt according to claim 1, wherein the canvas is impregnated with the surface rubber.   The toothed belt according to claim 1, wherein an internal adhesive is added to the surface rubber.   The toothed belt according to claim 3, wherein the adhesive is a resin adhesive.   The resin adhesive comprises at least one of maleic anhydride-modified liquid polybutadiene, maleic acid-modified liquid polybutadiene, acrylic acid-modified liquid polybutadiene, urethane-modified liquid polybutadiene, carboxylic-modified liquid polybutadiene, and maleic acid-modified liquid polyisoprene. The toothed belt according to claim 4. The toothed belt according to claim 5, wherein the resin adhesive is added to the surface rubber in an amount of 4 to 24 parts by weight with respect to 100 parts by weight of the fluororubber of the surface rubber.

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