JP2008298208A - High load transmission belt and center belt for high load transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high load transmission belt superior in bending resistance and heat resistance, without looseness between a center belt and a block, by preventing the occurrence of a crack by repetitive bending, with sufficient hardness, by further blending polyparaphenylene benzobisoxazole short fiber and carbon block by a predetermined quantity, by using hydride nitrile rubber. <P>SOLUTION: This high load transmission belt 1 is provided by fitting and fixing a plurality of blocks 2 at a predetermined pitch in the longitudinal direction of the center belts 3a and 3b. A rubber composition constituting the center belts 3a and 3b uses a material of blending the polyparaphenylene benzobisoxazole short fiber by 10-35 mass part and the carbon black by 35-70 pts.mass to the hydride nitrile rubber of 100 pts.mass. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high load transmission belt in which blocks are fitted and fixed at a predetermined pitch along the longitudinal direction of the center belt, and more specifically, a center belt excellent in hardness, bending resistance and heat resistance, and a high load using the same. Related to transmission belt.

  The belt used in the belt type continuously variable transmission is used by being wound around a transmission pulley that changes the effective diameter of the pulley by adjusting the V groove width of the pulley and adjusts the transmission gear ratio. Because the side pressure from the belt increases, the belt must withstand a large side pressure. In addition to continuously variable speed applications, it is necessary to use a belt that can withstand a high load especially for high load transmission applications where the life of conventional rubber belts is too short.

  Among such belts, there is a tensile transmission type high-load transmission belt in which a block is fixed to the center belt to increase the strength in the belt width direction. A block made of an elastomer that is relatively harder than the elastomer used for the center belt is fixed to the center belt embedded in the elastomer using a fixing material such as a bolt or a rivet.

  The center belt of such a high load transmission belt is made of an elastomer such as rubber, and the block is fitted and fixed. By running the belt, the center belt repeatedly receives compressive and shearing forces from the block, generating permanent distortion in the elastomer forming the center belt, weakening the fixing force between the block and the center belt, and wobbling the block This can lead to rattling, which can lead to increased noise when the belt travels, and can cause the center belt to crack and cut.

  To date, for example, Patent Document 1 discloses a hydrogenated nitrile to which an unsaturated carboxylic acid metal salt and an organic peroxide are added in order to increase the strength of the center belt and prevent problems such as rubber sag, wear, and cracks. It is disclosed that a rubber composition in which short fibers are blended with rubber is used as a center belt. Further, it is described that sulfur is blended and used as a co-crosslinking agent of an organic peroxide which is a crosslinking agent.

  Further, in Patent Document 2, by mixing nylon short fibers and aramid short fibers into the shape-retaining rubber of the center belt, the center belt is given high elasticity to ensure durability, and the friction coefficient is reduced to reduce noise. It is disclosed to prevent the occurrence of the above.

  Patent Document 3 proposes a belt in which the hardness of the center belt is secured and the flexibility of the belt is improved by blending hydrogenated nitrile rubber with short aramid fibers and carbon black.

  Further, in Patent Document 4, a carbon block and a short fiber are blended with hydrogenated nitrile rubber, and the short fiber is a combination of an aramid short fiber and a nylon short fiber, and the flexibility is maintained while maintaining the physical properties such as the center belt hardness. There has been disclosed a belt which is intended to extend the life of the belt by improving the above.

JP-A-5-272595 JP-A-6-2742 JP 2004-108420 A JP 2006-125630 A

  However, although the center belt as disclosed in Patent Document 1 has high hardness and can prevent the occurrence of trouble between the block and the center belt, it is weak against repeated bending and constitutes the center belt. This may lead to problems such as cracking due to bending of the rubber material.

  Further, although the center belt as disclosed in Patent Document 2 can reduce the occurrence of abnormal noise, the reinforcing effect of the center belt is reduced by the amount of blended nylon short fibers out of the amount of short fibers to be blended. Therefore, if the blending amount of the short fiber is increased too much in order to obtain a sufficient reinforcing effect, the short fiber acts as a foreign substance and causes cracking, so that the bending resistance is impaired.

  In Patent Document 3, although the bending resistance of the belt is improved as compared with the technique of Patent Document 1, it is not sufficient yet, and there is a problem that cracks occur from the crack to break as the belt runs for a long time. It remained. Although Patent Document 4 also shows an improvement in bending resistance, further improvement is required for a sufficiently long life.

  Accordingly, the present invention provides a high load transmission belt and a center belt for a high load transmission belt that have sufficient hardness and heat resistance to be used as a center belt of a high load transmission belt, and also have sufficient performance regarding bending resistance. Let it be an issue.

  In order to solve the above-mentioned problems, claim 1 of the present invention provides a center belt and a high load transmission belt in which a plurality of blocks are fitted and fixed at a predetermined pitch along the longitudinal direction of the center belt. And a high load transmission belt in which a plurality of blocks are fitted and fixed at a predetermined pitch along the longitudinal direction of the center belt, the rubber composition constituting the center belt is polyparaphenylene with respect to 100 parts by mass of the hydrogenated nitrile rubber. It is characterized by blending 10 to 35 parts by mass of benzobisoxazole short fibers and 35 to 70 parts by mass of carbon black.

  According to a second aspect of the present invention, in the high load transmission belt according to the first aspect, the rubber of the center belt is sulfur-based.

  The center belt and a center belt used for a high-load transmission belt in which a plurality of blocks are fitted and fixed at a predetermined pitch along the longitudinal direction of the center belt, wherein the rubber composition constituting the center belt is hydrogenated. 10 to 35 parts by mass of polyparaphenylene benzobisoxazole short fibers and 35 to 70 parts by mass of carbon black are blended with 100 parts by mass of nitrile rubber.

  According to a fourth aspect of the present invention, there is provided the center belt for a high load transmission belt according to the third aspect, wherein the rubber of the center belt is sulfur-based.

  According to claims 1 and 3 of the present invention, the hydrogenated nitrile rubber is used so that it has excellent heat resistance, and a predetermined amount of polyparaphenylene benzobisoxazole short fibers and carbon black are blended to form a high load transmission belt. A belt having sufficient hardness to be used can be improved in belt flexibility, and a belt with less failure such as generation of cracks due to bending deterioration can be provided.

  Claims 2 and 4 are advantageous in that the flexibility of the center belt can be improved by using sulfur as the crosslinking agent.

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

  FIG. 1 is a schematic perspective view showing an example of a high load transmission belt 1 according to the present invention. The high-load transmission belt 1 of the present invention is fixed to two center belts 3a and 3b having the same width formed by embedding a core wire 5 in a spiral shape in an elastomer 4, and the center belts 3a and 3b. A plurality of blocks 2. Both side surfaces 2a, 2b of the block 2 are inclined surfaces that engage with the V-grooves of the pulleys, and receive the power from the driven pulleys to lock and fix the centers 3a, 3b. Pulling, the power of the driving pulley is transmitted to the driven pulley.

  As shown in FIG. 1, the block 2 includes an upper beam portion 11 and a lower beam portion 12, and a center pillar 13 in which the central portions of the upper and lower beam portions 11 and 12 are connected to each other. Fitting grooves 14 and 15 for fitting the center belts 3a and 3b are formed in 2b. Further, on the groove upper surface 16 and the groove lower surface 17 in the fitting groove 15, the ridge portions 20, 21 that engage with the ridge portions 18 provided on the upper surfaces of the center belts 3 a, 3 b and the ridge portions 19 provided on the lower surface. To be engaged.

  FIG. 2 shows an example of another belt. A pair of side pillars 32 and 33 extend upward from both ends of the beam portion 31, and the upper ends of the side pillars 32 and 33 respectively extend toward the center of the block 2. The extending lock portions 34 and 35 are provided so as to face each other. The beam portion 31, the side pillars 32 and 33, and the lock portions 34 and 35 form a fitting groove 30 into which the center belts 3a and 3b are fitted. The center belts 3a and 3b are inserted into the fitting groove 30 through the opening between the lock portions 34 and 35 and attached. Further, a convex portion 37 is provided on each of the lock portions 34 and 35 on the fitting groove 30 side, and this convex portion 37 is fitted into the concave portion 36 provided at a predetermined pitch on the center belts 3a and 3b. To do. As a result, the center belts 3a and 3b are not easily removed from the block 2 after being mounted.

  What is used as the elastomer 4 of the center belts 3a and 3b in the present invention is hydrogenated nitrile rubber, and 10 to 35 parts by mass of polyparaphenylene benzobisoxazole short fibers with respect to 100 parts by mass of the hydrogenated nitrile rubber. Carbon black is blended in an amount of 35 to 70 parts by mass. Hydrogenated nitrile rubber is a material excellent in heat resistance, and also has high elasticity enough to keep the fitting state between the block and the center belt for a long period of time.

  If the blending amount of carbon black with respect to 100 parts by mass of hydrogenated nitrile rubber is less than 35 parts by mass, sufficient hardness cannot be obtained, and the occurrence of rattling between the center belt and the block will be accelerated, and the blending of carbon black If the amount exceeds 70 parts by mass, the bending resistance is suddenly lost, leading to early cutting of the belt.

  As the short fibers, short fibers made of polyparaphenylene benzobisoxazole (PBO) are used to further reinforce the high elasticity of the hydrogenated nitrile rubber and prevent wobbling between the center belt and the block. In addition, the bending resistance can be sufficient, the occurrence of cracks in the center belt can be prevented, and the life of the center belt can be greatly extended.

  In addition, when the blending amount of the polyparaphenylene benzobisoxazole short fiber is less than 10 parts by mass with respect to 100 parts by mass of the hydrogenated nitrile rubber, the hardness is also lowered, and rattling occurs between the center belt and the block. If the blending amount exceeds 35 parts by mass, the bending resistance is drastically reduced and cracks are accelerated, which leads to early cutting of the belt.

  In addition to polyparaphenylene benzobisoxazole short fibers and carbon black, sulfur vulcanizing system consisting of ordinary crosslinking agents, sulfur, sulfur-supplying compounds such as tetramethylthiuram disulfide, various vulcanization accelerators, and dicumyl An organic peroxide vulcanizing system such as peroxide is blended.

  Further, the crosslinking agent used may be either sulfur-based or peroxide-based. Examples of the sulfur type include sulfur, 4,4′-dithiobisdimorpholine, and tetramethylthiuram disulfide. Examples of the peroxide type include di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, 1 , 1-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-di-methyl-2,5-di (t-butylperoxy) hexane-3, bis (t-butylpooxy-di-isopropyl) benzene, Examples include 2,5-di-methyl-2,5-di (benzoylperoxy) hexane, t-butylperoxybenzoate, t-butylperoxy-2-ethyl-hexyl carbonate, and the like. In the present invention, it is preferable to use sulfur as the cross-linking agent, so that the flexibility of the center belt can be improved.

  Vulcanization accelerators may be blended as necessary, and specific examples include guanidine-based, thiuram-based, dithiocarbamic acid-based, thiazole-based, and sulfenamide-based vulcanization accelerators.

  In addition to the above, additives such as fillers, plasticizers, stabilizers, processing aids, anti-aging agents, colorants, etc. that improve wear resistance, such as calcium carbonate and talc, which are usually blended in rubber are also used. It is possible to mix according to. The method of mixing these compounding agents also includes a method of kneading using a commonly used means such as a Banbury mixer or a kneader.

  As the core 5, a rope selected from polyester fiber, polyamide fiber, aramid fiber, glass fiber, steel wire and the like is used. The core wire 5 may be made of a woven fabric, knitted fabric, metal thin plate, or the like of the above-mentioned fiber other than a rope embedded in a spiral shape.

  The block 2 is made of a synthetic resin material. For example, an insert material having a substantially block shape made of a metal such as an aluminum alloy may be embedded inside, or the insert material may be embedded. It does n’t matter if you do n’t. In addition to the insert material, for example, a reinforcing material such as a short fiber or whisker added in a form mixed in the synthetic resin material may be added.

  The block resin can be either a thermoplastic resin or a thermosetting resin, and the thermoplastic resin is a polyamide resin such as 6,6-nylon, 4,6-nylon, 9, T-nylon. Synthetic resins such as polyamideimide (PAI) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (PI) resin, polyethersulfone (PES) resin, polyetheretherketone (PEEK) resin Used. On the other hand, as the thermosetting resin, hard rubber having a hardness of 90 ° JIS A or more, hard polyurethane resin, liquid crystal resin, phenol resin, epoxy resin, polyester resin, acrylic resin, methacrylic resin, polyamide resin, polyamideimide (PAI) resin Rubber, such as polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (PI) resin, polyether sulfone (PES) resin, polyether ether ketone (PEEK) resin, and synthetic resins are used.

  In the present invention, long fibers are blended in the synthetic resin forming the block as described above, but it is also possible to blend a whisker-like reinforcing material, specifically, zinc oxide whisker and titanium. Inorganic fibers such as potassium acid whisker and aluminum borate whisker may be blended. In these, it is preferable to use a zinc oxide whisker. The zinc oxide whisker has a three-dimensional shape with hands extending in all directions in a tetrapot shape. This zinc oxide whisker alone is excellent in heat resistance and wear resistance, but because it has a tetrapod-like three-dimensional shape as described above, when blended with carbon fiber, the orientation of carbon fiber Is suppressed, and anisotropy of warpage during molding and molding shrinkage is improved. Further, since the orientation of the carbon fibers can be reduced in this way, the anisotropy of strength such as toughness and bending rigidity of the block 2 can be reduced, and the friction coefficient is stabilized, so that the wear resistance is improved. To do.

  Moreover, since the zinc oxide whisker has a high specific gravity and high rigidity, it is possible to reduce vibration during contact with the pulley and to reduce noise generation. In addition, when there are few compounding quantities of this zinc oxide whisker, the added effect does not express, and when too large, it cannot knead | mix and it becomes difficult to shape | mold.

  By adopting such a material structure, it has strength such as rigidity and toughness that can sufficiently withstand the side pressure received when it comes into contact with the pulley, has excellent wear resistance, and further, with respect to heat generated during friction. The power received from the pulley can be efficiently transmitted as a tensile force to the center belts 3a and 3b, and a tension transmission type high load transmission belt can be configured.

  In addition to these, the lubricity of the block 2 can be improved by mixing at least one selected from molybdenum disulfide, graphite, and fluorine-based resin. Examples of the fluorine-based resin include polytetrafluoroethylene (PTFE), polyfluorinated ethylene propylene ether (PFPE), tetrafluoroethylene hexafluoropropylene copolymer (PFEP), polyfluorinated alkoxyethylene (PFA), and the like. .

  Next, the rubber composition used in the high load transmission belt and the center belt for the high load transmission belt of the present invention, the type of rubber, the amount of carbon black, and the amount of short fibers are out of the scope of the present invention. A comparative test was performed using the prepared test piece.

Example 1
In Example 1, 30 parts by mass of polyparaphenylene benzobisoxazole (PBO) short fibers (ZYLON Toyobo Co., Ltd.) and carbon black (N220) are added to 100 parts by mass of hydrogenated nitrile rubber (Zetpole 2020, manufactured by Nippon Zeon Co., Ltd.). 60 parts by mass of Tokai Carbon Co., Ltd., other anti-aging agents, softeners, zinc oxide, sulfur, and crosslinking accelerators are blended in the blending amounts shown in Table 1, kneaded, molded into a predetermined thickness, and hot pressed And a test sample was crosslinked at 153 ° C. for 30 minutes. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

(Example 2)
Example 2 was prepared in the same manner as in Example 1 except that the amount of carbon black was 40 parts by mass, and kneaded and crosslinked to prepare a test sample. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

(Example 3)
Example 3 was blended in the same manner as in Example 1 except that the blending amount of polyparaphenylene benzobisoxazole (PBO) short fibers was 10 parts by mass and the blending amount of carbon black was 70 parts by weight. A test sample was prepared. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

Example 4
Example 4 was prepared in the same manner as in Example 1 except that peroxide was used without using sulfur as a cross-linking agent, and kneaded and cross-linked to prepare a test sample. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

(Comparative Example 1)
Comparative Example 1 was blended in the same manner as in Example 1 except that the blending amount of polyparaphenylene benzobisoxazole (PBO) short fibers was 40 parts by mass and the blending amount of carbon black was 60 parts by mass. A test sample was prepared. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

(Comparative Example 2)
Comparative Example 2 was blended in the same manner as in Example 1 except that the blending amount of polyparaphenylene benzobisoxazole (PBO) short fibers was 5 parts by mass, and the blending amount of carbon black was 70 parts by weight. A test sample was prepared. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

(Comparative Example 3)
Comparative Example 3 was blended in the same manner as in Example 1 except that the blending amount of polyparaphenylene benzobisoxazole (PBO) short fibers was 10 parts by mass, and the blending amount of carbon black was 80 parts by weight. A test sample was prepared. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

(Comparative Example 4)
Comparative Example 4 was blended in the same manner as in Example 1 except that the blending amount of the polyparaphenylene benzobisoxazole (PBO) short fibers was 30 parts by mass and the blending amount of carbon black was 30 parts by mass. A test sample was prepared. Using the test sample, the hardness was measured, and the number of flexing until the crack reached 10 mm was measured by the Dematcher flexing test.

  Further, a center belt having a belt pitch width of 18 mm and a pitch circumferential length of 600 mm is prepared, and a block having a shape as shown in FIG. 1 is molded from 4,6-nylon and attached to the center belt. A belt was produced and a running test was performed. The presence or absence of wobbling of the block after 50 hours of running was confirmed, and the time until belt breakage was measured for those without wobbling.

  The formulations of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1, the test conditions of the running test are shown in Table 2, and the test results are shown in Table 3.

  As can be seen from the results in Table 3, Examples 1 to 3 obtained good results in the bending test while maintaining a certain degree of hardness. In the belt running test, no block wobble occurred and the time until the belt broke was longer than that of the comparative example.

  Example 5 uses peroxide instead of sulfur as a cross-linking agent, but has poor flexibility and poor results in running tests as compared to Example 1 in which the PBO short fibers, carbon black, and other ingredients are the same. Thus, it was found that a better belt can be obtained when sulfur is used.

  In Comparative Example 1 having a large amount of PBO short fibers, the hardness was high, the result of the bending test was poor, and the time until the belt broke was also short. On the contrary, in Comparative Example 2 where the blending amount of PBO short fibers is small, the result of the bending test is good and the flexibility is excellent, but the hardness is low and the wobble between the block and the belt occurs early and the belt breaks. It became a failure without reaching.

  In Comparative Example 3 in which the amount of carbon black was large, the hardness was high and the bending test was bad. Even in the running test, the belt was cut in a short time. It is thought that cracks occurred early. On the contrary, in Comparative Example 4 in which the amount of carbon black was small, the hardness was low, and the wobble between the block and the belt occurred at an early stage, and the belt did not break and failed.

  The present invention can be applied to the manufacture of belts that change the effective diameter of pulleys and transmit large torque, such as continuously variable transmissions for automobiles, motorcycles, and agricultural machines.

It is a perspective schematic diagram showing an example of the high load transmission belt concerning the present invention. It is a perspective schematic diagram showing other examples of the high load power transmission belt concerning the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High load power transmission belt 2 Block 3a Center belt 3b Center belt 4 Elastomer 5 Core wire 11 Upper beam part 12 Lower beam part 13 Center pillar 14 Fitting groove 15 Fitting groove

Claims (4)

  In the center belt and a high load transmission belt in which a plurality of blocks are fitted and fixed at a predetermined pitch along the longitudinal direction of the center belt, the rubber composition constituting the center belt is a poly-polyethylene with respect to 100 parts by mass of hydrogenated nitrile rubber. A high load transmission belt comprising 10 to 35 parts by mass of paraphenylenebenzobisoxazole short fibers and 35 to 70 parts by mass of carbon black.   The high-load transmission belt according to claim 1, wherein the rubber of the center belt is sulfur-based.   In a center belt used for a center belt and a high load transmission belt in which a plurality of blocks are fitted and fixed at a predetermined pitch along the longitudinal direction of the center belt, the rubber composition constituting the center belt is 100 parts by mass of hydrogenated nitrile rubber. A center belt for a high load transmission belt, comprising 10 to 35 parts by mass of polyparaphenylene benzobisoxazole short fibers and 35 to 70 parts by mass of carbon black.   The center belt for a high load transmission belt according to claim 3, wherein the rubber of the center belt is sulfur-based.

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