JP2008157440A - High load transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt reducing pitch noise made when the belt travels without degrading strength such as wear resistance and rigidity of blocks. <P>SOLUTION: This high load transmission belt 1 comprises a plurality of blocks 2 provided at the predetermined pitch along the longitudinal direction of a center belt 3. The block 2 is formed of a resin composition prepared by mixing a fiber reinforced material comprising carbon fiber, aramid fiber, or the like, and a friction reducing material comprising polytetrafluorethylene, ultrahigh molecular weight polyethylene, or the like, into thermoplastic resin. The fiber reinforcing material of 10-40 mass% and the friction reducing material of 1-20 mass% are mixed to the total quantity of the resin composition. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high-load transmission belt in which blocks are fixed at a predetermined pitch along the longitudinal direction of a tension band.

  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.

  As the block, a metal core material such as aluminum whose surface is coated with a resin has been proposed (Patent Document 1). However, due to diversification of needs, the load is somewhat low, but the rotation speed is high and the pulley diameter is small. A block having a metal core material inevitably increases the weight of the core material, and when the belt is run at a high speed, there is a problem that the centrifugal tension increases and the belt is damaged early.

  Therefore, a belt using a block made only of a resin material without using a core material has been proposed. Patent Document 2 reinforces a thermoplastic resin such as polyamide 46 (nylon 46) by blending PAN-based carbon fiber and whisker, and can withstand lateral pressure without being embedded, and is lightweight. From this, it is described that the centrifugal tension during running of the belt is small and the belt can be prevented from being damaged.

  Furthermore, Patent Document 3 describes a high-load transmission belt that uses a polyamide 9T (nylon 9T) as a polyamide resin to reduce the weight without using a core material and is further superior in strength. Yes.

  Patent Documents 2 and 3 describe blending various whiskers.

Japanese Patent Laid-Open No. 10-73149 JP 2001-31453 A JP 2002-195351 A

  By using a resin reinforced with fibers or whiskers as described above, the wear resistance and rigidity of the block can be increased. However, if a center belt with a large number of blocks is wound around a pulley and run, pitch noise is generated when the block periodically contacts the pulley, which is a problem of noise.

  The pitch noise tends to increase as the strength of the block increases, and improvement in strength and reduction in noise are conflicting problems that are difficult to solve.

  Accordingly, an object of the present invention is to provide a belt that can reduce pitch noise generated when the belt travels without reducing strength such as wear resistance and rigidity of the block.

  In order to achieve the above object, according to claim 1 of the present invention, a center belt in which a core is embedded in an elastomer, and a plurality of blocks provided at a predetermined pitch along the longitudinal direction of the center belt. In the high-load transmission belt, at least the surface of the block that contacts the pulley is made of a resin composition in which at least a fiber reinforcing material and a friction reducing material are blended with a thermoplastic resin, and the fiber reinforcing material with respect to the total amount of the resin composition Is 10 to 40% by mass, and the friction reducing material is blended at a rate of 1 to 20% by mass.

  According to a second aspect of the present invention, in the high load transmission belt according to the first aspect, the friction reducing material is a fluororesin and is blended in the range of 5 to 15% by mass.

  According to a third aspect of the present invention, in the high load transmission belt according to the first aspect, the friction reducing material is an ultrahigh molecular weight polyethylene and is blended in the range of 2 to 8% by mass.

  The high load transmission belt according to claim 3, wherein the ultra high molecular weight polyethylene has a particle size of 10 to 50 µm.

  The high load transmission belt according to claim 1, wherein the thermoplastic resin is 4,6-nylon or 9, T-nylon.

  In Claim 6, it is set as the high load power transmission belt of Claims 1-5 formed by arrange | positioning the resin composition which does not contain a friction reducing material in parts other than a contact surface with a pulley.

  In claim 1, since the fibrous reinforcing material and the friction reducing material are blended in the block made of the thermoplastic resin, the block is light and suitable for use at high rotation, and the block has sufficient strength. In addition, the pitch noise generated by the contact between the block and the pulley during belt running can be suppressed to a low level.

  According to the second aspect of the present invention, the fluororesin is used as the friction reducing material, and the frictional resistance between the block and the pulley can be reduced. Therefore, the sound generation is reduced and the pitch noise can be reduced.

  According to the third aspect, the ultrahigh molecular weight polyethylene is used as the friction reducing material, and the frictional resistance between the block and the pulley can be reduced, so that the sound generation is reduced and the pitch noise can be reduced.

  According to the fourth aspect of the present invention, the ultra high molecular weight polyethylene has a small particle diameter and is excellent in dispersibility, so that it is effective in improving lubricity, wear resistance and impact resistance, and good mechanical properties can be obtained.

  In claim 5, 4,6-nylon or 9, T-nylon is used as the thermoplastic resin. 4,6-nylon or 9, T-nylon is a crystalline resin, and among these thermoplastic resins. It excels in bending rigidity and fatigue resistance at high temperatures, and by adding carbon fiber as a reinforcing material to these, these characteristics are further improved. Furthermore, a belt using a block made of polyamide 46 has a small amount of wear on the pulley when the belt runs on the pulley.

  In claim 6, the resin composition not containing the friction reducing material is used except for the contact surface with the pulley, but the resin composition containing the friction reducing material has a low coefficient of friction and the effect of reducing noise. However, there is a tendency to decrease in strength, and by placing a resin composition that does not contain a friction reducing material other than the contact surface with the pulley, the entire block without impairing the effect of reducing pitch noise Strength can be increased.

  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, and FIG. 2 is a side view. 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 and 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 and are locked and fixed by the center belts 3a and 3b. The power of the driving pulley is transmitted to the driven pulley.

  As shown in FIGS. 1 and 2, the block 2 includes an upper beam 11 and a lower beam 12, and pillars 13 that connect the central portions of the upper and lower beams 11 and 12, and both side surfaces 2 a and 2 b of the block 2. Are formed with grooves 14 and 15 into which the pair of center belts 3a and 3b are fitted. Further, the groove upper surface 16 and the groove lower surface 17 in the groove 15 are related to the ridge portions 20 and 21 engaged with the ridge portion 18 provided on the upper surface of the center belt 3a, 3b and the ridge portion 19 provided on the lower surface. It comes to match.

  Further, in the present invention, the material used on at least the surface of the block 2 that contacts the pulley is composed of a resin composition in which at least a fiber reinforcing material and a friction reducing material are blended with a thermoplastic resin. The material is blended at a rate of 10 to 40% by mass, and the friction reducing material is blended at a rate of 1 to 20% by mass.

  By using the resin composition containing the friction reducing material as described above on the contact surface of the block 2 with the pulley, the friction coefficient of the resin can be lowered, and when the block 2 enters the pulley or escapes from the pulley. The impact noise and rubbing sound that occurs when the belt travels are greatly reduced, and the effect of suppressing pitch noise during belt running is demonstrated.

  On the other hand, it is preferable to use a resin composition in which a friction reducing material is not blended for portions other than the surface in contact with the pulley in the block 2. The resin composition containing the friction reducing material has the effect of suppressing the pitch noise by reducing the friction coefficient, but the strength tends to decrease, and the strength of the block is originally increased for the purpose of high load transmission. It is preferable. Therefore, the strength of the entire block can be increased without impairing the effect of reducing pitch noise by using a resin composition that does not contain a friction reducing material in a portion other than the contact surface with the pulley.

  The resin composition not containing the friction reducing material is composed of a resin composition in which at least a fiber reinforcing material is added to a thermoplastic resin, and the fiber reinforcing material is in a ratio of 10 to 40% by mass with respect to the total amount of the resin composition. It is preferable to mix with.

  For example, as shown in FIG. 3, only the outer surface S including the contact surface with the pulley of the block 2 is a resin composition containing a friction reducing material, and the inner core portion C is a resin composition not containing a friction reducing material. Although it is possible to reduce pitch noise and secure strength by making it a product, it is possible to achieve friction only on the outer surface by a multicolor molding method or a sandwich molding method that is generally known as a molding method. A block in which a resin containing a reducing material is arranged can be molded.

  When it is set as the block of such a form, it is preferable to make the thickness of the layer of the outer surface which consists of a resin composition which mix | blended the friction reducing material in the contact surface with a pulley into the range of 0.3-1.0 mm. If the thickness is less than 0.3 mm, the effect of noise reduction is lost early because it is easily damaged or worn. If the thickness exceeds 1.0 mm, the effect of the outer surface is maintained over a long period of time. Since the ratio of the core part which does not mix | blend a friction reducing material decreases and an intensity | strength fall becomes large too much, it is unpreferable.

  Examples of the thermoplastic resin include 4,6-nylon, 9, T-nylon, polyphenylene sulfide, polyether ether ketone, polyether sulfone, and polyamideimide. Among these, it is preferable to use 4,6-nylon or 9, T-nylon. 4,6-Nylon and 9, T-Nylon are crystalline resins that are superior in bending synthesis and fatigue resistance at high temperatures among thermoplastic resins, and these properties can be further improved by adding fiber reinforcements. It is. In addition, since injection molding is possible, there is an advantage that it is easier to mold the block. Furthermore, since belts using blocks made of 4,6-nylon or 9, T-nylon are less likely to wear the pulley when running, there is less of a problem of unstable running due to wear of the pulley. .

  9, T-nylon is a polyamide resin having an aromatic ring and a long chain diamine, which is produced by polycondensation of nonanediamine and terephthalic acid, and is represented by the general formula 1.

  Since it has an aromatic ring and a higher aliphatic chain, it has heat resistance and low water absorption. Further, since it is a homopolymer and has a high degree of crystallinity, it is excellent in wear resistance, impact resistance and fatigue resistance as in the case of 4,6-nylon compared to polyamide having a low degree of crystallinity. Therefore, by using this material, it is possible to obtain a block having excellent physical properties such as wear resistance, impact resistance, fatigue resistance, and bending rigidity during heating, and having few water absorption problems. As an example of the product of 9, T-nylon, “Genesta” of Kuraray Co., Ltd. can be mentioned.

  Although the rigidity and wear resistance of the block can be improved by blending a fiber reinforcing material, the fiber reinforcing material used in the present invention is a short fiber made of carbon fiber, aramid fiber, glass fiber, polyester fiber, etc. Can be mentioned. Among these fibers, it is most preferable to use carbon fibers, and more preferable to use PAN-based carbon fibers from the viewpoints of increasing the rigidity of the block and improving the wear resistance.

  PAN-based carbon fiber is a fiber having a high elastic modulus and a high reinforcing effect in the first place. Among them, by using a fiber having a particularly high elastic modulus of 280 to 700 GPa, as a block of a high load transmission belt as in the present invention. It is possible to provide a material that can withstand sufficient use. If the elastic modulus is less than 280 GPa, the side pressure resistance of the block can be obtained to some extent, but the wear resistance is insufficient, and if it exceeds 700 GPa, even if the elastic modulus is high, the improvement of the side pressure resistance and wear resistance is not improved. Since it is not seen so much and becomes expensive, it is not preferable.

  The length of the short fiber is usually about 1 to 5 mm. If the length is less than 1 mm, the block is not sufficiently reinforced, and if the length exceeds 5 mm, it is difficult to mix and mold the thermoplastic resin. The blending amount of the fiber reinforcing material is 10 to 40% by mass, and if it is less than 10% by mass, a sufficient reinforcing effect cannot be obtained, and if it exceeds 40% by mass, block injection molding becomes difficult, which is not preferable. .

  Examples of the friction reducing material include fluororesin, ultra high molecular weight polyethylene (UHMW-PE), graphite, molybdenum disulfide, and the like. If it is less than 1% by mass, the problem of wear resistance and the effect of lowering the coefficient of friction described later are small, and if it exceeds 20% by mass, it becomes difficult to blend into the resin.

  Among these friction reducing materials, when a fluororesin is used, it is particularly preferable to blend in the range of 5 to 15% by mass with respect to the thermoplastic resin. If it is less than 5% by mass, the effect of reducing the noise generated when the block and pulley come into contact with each other cannot be sufficiently obtained. If it exceeds 15%, the sound can be reduced, but the strength of the block decreases. This is not preferable because sufficient physical properties cannot be obtained.

  Examples of the fluororesin include polytetrafluoroethylene (PTFE), polyfluorinated ethylenepropyl ether (PFPE), tetrafluoroethylene hexafluoropropylene copolymer (PFEP), polyfluorinated alkoxyethylene (PFA), and the like.

  Moreover, when using ultra high molecular weight polyethylene, it is preferable to mix | blend in 2-8 mass% especially with respect to a thermoplastic resin. As in the case of blending the fluororesin, if it is less than 2% by mass, the effect of reducing the noise generated when the block and the pulley come into contact with each other cannot be sufficiently obtained. If it exceeds 8%, the sound can be reduced. On the other hand, it is not preferable because the strength of the block is lowered and sufficient physical properties cannot be obtained. Moreover, when using ultra high molecular weight polyethylene, the average particle diameter can use the thing of the range of 10-50 micrometers. If the particle size is less than 10 μm, the production becomes difficult, and if the particle size exceeds 50 μm, the strength decreases.

  By blending graphite, graphite can be transferred to the pulley to reduce abrasive wear, and wear resistance can be improved. In addition, since the friction coefficient can be lowered, there is also an effect of suppressing the level of sound generation due to contact between the block and the pulley.

  When a fluororesin is blended, it can be transferred to a pulley in the same manner as graphite, thereby reducing abrasive wear and improving wear resistance. Although the friction coefficient can be lowered although the effect of reducing the abrasive wear is less than that of graphite, it also has the effect of suppressing the level of sound generation caused by contact between the block and the pulley. Further, there is an advantage that the physical properties of the block are less deteriorated than graphite.

  By blending molybdenum disulfide, it is also possible to improve the wearability to transfer to the pulley and reduce the abrasive wear. Further, there is an effect of reducing the friction coefficient, and the friction coefficient can be adjusted. There is also an advantage that it is less susceptible to temperature and humidity than graphite.

  A material used as the elastomer 4 of the center belts 3a and 3b is a single material such as chloroprene rubber, natural rubber, nitrile rubber, styrene-butadiene rubber, hydrogenated nitrile rubber or rubber or polyurethane rubber obtained by appropriately blending these. Can be mentioned. As the core 5, a rope selected from polyester fiber, polyamide fiber, aramid fiber, glass fiber, steel wire and the like is used. Moreover, the core wire 5 can also use the woven fabric, knitted fabric, metal thin plate, etc. which consist of said fiber other than what embedded the rope in spiral shape.

  Next, a block using a high load transmission belt which is an embodiment of the present invention using a block in which a predetermined amount of fluororesin or ultra high molecular weight polyethylene is blended, and a high load transmission belt which is a comparative example out of the present invention, The friction coefficient and the pitch noise during belt running were compared.

(Example 1)
The belt block of Example 1 used 4,6-nylon containing 30% by mass of carbon fiber as a fiber reinforcing material and 10% by mass of polytetrafluoroethylene (PTFE) as a friction reducing material. As the center belt, an aramid fiber was used for the core wire 5 and chloroprene rubber was used for the elastomer 4. The belt size was a belt pitch width of 18 mm, a pitch circumferential length of 498 mm, and a block pitch of 3 mm.

  First, the friction coefficient of the block was measured using this belt. The measurement conditions were a pressing force of 1.5 MPa and a sliding speed of 0.5 m / s. Next, noise during belt running was measured. The number of rotations was 6000 rpm. The results are shown in Table 1.

(Example 2)
In Example 2, a belt similar to that in Example 1 was prepared except that a block containing 5% by mass of ultrahigh molecular weight polyethylene (UHMW-PE) instead of polytetrafluoroethylene (PTFE) was used as a friction reducing material.

  First, the friction coefficient of the block was measured using this belt. The measurement conditions were a pressing force of 1.5 MPa and a sliding speed of 0.5 m / s. Next, noise during belt running was measured. The number of rotations was 6000 rpm. The results are shown in Table 1.

(Comparative example)
In the comparative example, a belt was prepared in the same manner as in Example 1 except that polytetrafluoroethylene (PTFE), which is a friction reducing material, was not blended.

  First, the friction coefficient of the block was measured using this belt. The measurement conditions were a pressing force of 1.5 MPa and a sliding speed of 0.5 m / s. Next, noise during belt running was measured. The number of rotations was 6000 rpm. The results are shown in Table 1.

  As can be seen from the results in Table 1, in a belt using a block blended with polytetrafluoroethylene (PTFE) or ultra high molecular weight polyethylene (UHMW-PE), the friction coefficient of the block is low, which occurs when the belt is run. It can be seen that the pitch noise is reduced.

  Belts that can prevent cracks by suppressing multiple directions of bending of blocks attached to the belt, such as cars, motorcycles, continuously variable transmissions for agricultural machinery, etc., belts that change the effective diameter of pulleys and transmit large torque Can be applied as

It is a perspective schematic diagram showing an example of the high load transmission belt concerning the present invention. It is a side view of the high load power transmission belt concerning the present invention. It is a front view of a block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High load transmission belt 2 Block 3a Center belt 3b Center belt 4 Elastomer 5 Core body 6 Upper surface 7 Lower surface 11 Upper beam part 12 Lower beam part 13 Center pillar 14 Fitting groove 15 Fitting groove 18 Convex part 19 Convex part 20 Groove part 21 Groove part S Outer surface C Core part

Claims (6)

  In a high load transmission belt comprising a center belt in which a core body is embedded in an elastomer and a plurality of blocks provided at a predetermined pitch along the longitudinal direction of the center belt, at least the surface of the block that contacts the pulley is thermoplastic. It consists of a resin composition in which at least a fiber reinforcing material and a friction reducing material are blended in the resin, and the fiber reinforcing material is 10 to 40% by mass and the friction reducing material is 1 to 20% by mass with respect to the total amount of the resin composition. A high-load power transmission belt characterized by blending.   The high load transmission belt according to claim 1, wherein the friction reducing material is a fluororesin and is blended in a range of 5 to 15 mass%.   The high load transmission belt according to claim 1, wherein the friction reducing material is ultra high molecular weight polyethylene and is blended in the range of 2 to 8% by mass.   The high load transmission belt according to claim 3, wherein the ultra high molecular weight polyethylene has a particle size of 10 to 50 μm.   The high-load transmission belt according to claim 1, wherein the thermoplastic resin is 4,6-nylon or 9, T-nylon.   The high load transmission belt according to claim 1, wherein a resin composition not including a friction reducing material is disposed in a portion other than the contact surface with the pulley.

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