JP4749825B2 - High load transmission belt and method of manufacturing block used therefor - Google Patents

Description

  The present invention relates to a high-load transmission belt in which a block is fixed at a predetermined pitch along the longitudinal direction of the center belt and a manufacturing method of the block used therefor, and more specifically, by distributing the concentration of stress generated in the block during belt running. It relates to those that prevent block breakage.

  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 required quality of the block used for such a tension transmission type high load transmission belt, since it is intended for high load transmission in friction transmission as described above, bending fatigue, wear resistance, heat resistance, It is necessary to have a good balance of properties such as rigidity and impact resistance. Another important factor is not to wear the pulley.

  An example of a high load transmission belt that satisfies these requirements is disclosed in Patent Document 1. This belt uses a double-structured block in which the part where the block and pulley come into contact is coated with an insert material made of metal or the like by a resin molding material in which a rubber component is added to a phenolic resin component. It is.

  In Patent Document 1, a phenolic resin is mixed with 25 to 60 parts by weight of a fiber containing two fibers of carbon fiber and aramid fiber using acrylonitrile-butadiene rubber as a matrix, and the carbon fiber has an onion structure. A high-load transmission belt using a block using a phenolic resin having a crystal layer thickness of 25 to 200 μm is disclosed.

  As the block, there has been proposed a block in which a resin is coated on the surface of a metal insert material such as aluminum (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. The block having the metal insert material inevitably increases the weight of the insert material. 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 fibers and whiskers, and can withstand lateral pressure without an embedded insert, and is lightweight. For this reason, it is described that the centrifugal tension during running of the belt is small and the belt can be prevented from being damaged.

  Further, Patent Document 3 describes a high-load transmission belt that is made lighter without using an insert material by using polyamide 9T (nylon 9T) as a polyamide resin and that is further superior in strength. ing.

Japanese Examined Patent Publication No. 7-110900 JP 2001-31453 A JP 2002-195351 A

  Although the purpose of weight reduction of the belt is achieved by using the belt as disclosed in Patent Document 2 and Patent Document 3, there is a place where the strength is inferior because there is no insert material made of metal or the like. . We are trying to improve the strength by blending short fibers and whiskers, and using materials with excellent strength, but cracks occur in areas where the block stress tends to concentrate while the belt is running. There is a problem that it eventually breaks.

  Accordingly, the present invention provides a belt of the type in which such a block is mounted on the center belt, and in the fitting groove, where stress is particularly concentrated in the block and cracking is likely to occur while maintaining the light weight without embedding the insert material. An object of the present invention is to provide a belt having a longer life by relaxing stress concentration near the boundary between the lower beam and the pillar and preventing breakage of the block.

In order to solve the above-described problems, a first aspect of the present invention provides a center belt in which a core body is embedded in an elastomer, and a plurality of blocks are fitted and attached along the longitudinal direction of the center belt. In the high-load transmission belt, the block consists of pillars that connect and integrate the centers of the upper and lower beams and the upper and lower beams, and form fitting grooves on both sides of the block. It is made of a blended resin material, and the short fibers are oriented at an angle of 45 ° or less with respect to the belt width direction in the vicinity of the boundary between the lower beam and the pillar.

  Claim 2 is a high load transmission belt in which the resin material constituting the block is any of 4,6-nylon, 9, T-nylon, polyphenylene sulfide, polyether ether ketone, polyether sulfone, and polyamide imide. is there.

According to a third aspect of the present invention, there are provided a plurality of blocks comprising a center belt in which a core body is embedded in an elastomer, and pillars that connect and integrate the centers of the upper beam, the lower beam, and the upper and lower beams along the longitudinal direction of the center belt. In a block manufacturing method in which a block used for a high load transmission belt provided by fitting and fitting is formed by injection molding a resin in which short fibers are mixed in a mold, the mold has a surface near the upper surface of the upper beam of the block. A gate is arranged at a corresponding position or a position corresponding to the vicinity of the center of the pillar, and a block is formed by injecting a resin raw material from the upper beam side using the mold.

  According to a fourth aspect of the present invention, there is provided a high load transmission belt in which a resin material constituting the block is any of 4,6-nylon, 9, T-nylon, polyphenylene sulfide, polyether ether ketone, polyether sulfone, and polyamide imide. It is a manufacturing method of the block to be used.

  In claim 1, at the boundary between the lower beam and the pillar where stress is concentrated in the block when the belt is run, the orientation direction of the short fibers blended in the block is the vertical direction of the block in which cracks and cracks occur. By making the width direction of the belt, which is the vertical direction, stress can be dispersed, the concentrated stress can be reduced, and cracking can be prevented.

  In claim 2 and claim 4, the resin material constituting the block is limited, and in combination with the orientation of the short fibers in claim 1, a block having excellent strength can be formed by injection molding, and a high load transmission belt It can be.

  According to the third aspect of the present invention, the short fiber can be oriented in the width direction of the belt by setting the gate position to the upper beam side, and in particular, the stress concentrated on the boundary portion between the lower beam and the pillar is dispersed to generate cracks. In addition to being V-shaped and tapered on the front and back surfaces of the block so as not to inhibit the bending of the belt, the volume of the upper beam is larger than the lower beam. By providing the gate on the upper beam side having a large volume, it is easy to obtain the pressure retaining effect of the resin pressure in the mold at the time of injection molding, and a good block can be molded. Further, the orientation direction of the short fibers in the vicinity of the boundary portion between the lower beam and the pillar can also be set to the belt width direction by setting the position of the pillar.

  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 8 and 9 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 the center belts 3a and 3b that are locked and fixed. 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 fitting grooves 14 and 15 for the pair of center belts 3a and 3b. Further, the groove upper surface 16 and the groove lower surface 17 in the fitting grooves 14 and 15 are provided with a ridge portion 18 provided on the upper surface of the center belts 3a and 3b and a ridge portion 20 engaged with a groove portion 19 provided on the lower surface. , 21 is engaged.

  Further, as shown in FIG. 2, the front and rear surfaces 6 and 7 of the block 2 are formed with tapered surfaces whose thickness decreases as the belt 2 moves downward so that the belt can be wound around a pulley or the like. The tapered surface may extend over the entire height direction of the block 2 or may be a tapered surface formed in the other lower half of the block 2, and the tapered surfaces are provided on both the front and rear surfaces of the block. Or any one side. Anyway, since such a tapered surface is provided, the lower beam 12 of the block 2 is smaller in volume than the upper beam 11.

  In such a belt, a large stress is applied to the block during the running of the belt, but the stress tends to concentrate particularly at the boundary where the lower beam 12 is connected to the pillar 13. There is a problem that the belt is broken in the vertical direction and the life of the belt is reached. By orienting short fibers in the belt width direction perpendicular to the vertical direction, which is the direction in which the block 2 breaks, at locations where stress is likely to concentrate during belt running, stress concentration is mitigated and cracks are prevented as much as possible. And the life of the belt can be extended.

  Therefore, in the present invention, as the material of the block 2, a resin composition in which short fibers are blended with a resin material is used, which is molded by injection molding. In the present invention, the short fibers 41 in the resin 40 forming the block 2 in the vicinity of the boundary A between the lower beam 12 and the pillar 13 (see FIG. 4) in the shape of the block 2 as described above are equal to the belt width direction. Alternatively, it is oriented at an angle within 45 °, more preferably within 15 ° from the belt width direction. In the fitting groove, the vicinity A of the boundary between the lower beam 12 and the pillar 13 is the boundary K where the lower beam 12 and the pillar 13 are connected in the region shown in FIG. It means the range within 4.0mm downward.

  A large effect can be expected if the short fibers 41 are oriented in the belt width direction from the top to the bottom of the lower beam 12 in the vertical direction, but this is not always necessary, and stress is concentrated to cause cracks. This is from the inside of the fitting grooves 14 and 15 and extends downward from the block 2, so that the orientation of the short fibers 41 is above the center of the lower beam 12 in the vertical direction of the block 2 in the belt width direction. It is preferable that If the short fibers 41 are oriented in the vicinity of the surfaces in the fitting grooves 14 and 15, the generation of cracks can be suppressed more effectively, but they are particularly well oriented inside even if they are not oriented on the surface. Even if it exists, the effect that the crack of a block is not advanced can be show | played, and it is included in this invention.

  The block 2 used in the high load transmission belt 1 of the present invention is made of a material in which short fibers 41 are blended with a thermoplastic resin 40. In some cases, a whisker-like reinforcing material or the like is used to improve the strength of the block 2. May be blended. The short fiber 41 is blended at a ratio of 1 to 60% by mass with respect to the resin, has strength such as rigidity and toughness that can sufficiently withstand the side pressure received when contacting the pulley, and has excellent wear resistance. It is possible to make the block strong against heat generated at the time of friction, and the power received from the pulley can be efficiently transmitted as a tensile force to the center belt 3 to constitute a tension transmission type high load transmission belt. Can do.

  Examples of the thermoplastic resin used in the block 2 include 4,6-nylon, 9, T-nylon, polyphenylene sulfide, polyether ether ketone, polyether sulfone, and polyamideimide. Of these, 4,6-nylon is preferably used. 4,6-Nylon is a crystalline resin, and among these thermoplastic resins, it has excellent bending rigidity and fatigue resistance at high temperatures, and these characteristics are further improved by adding carbon fiber, which will be described later, as a reinforcing material. To do. Further, since injection molding is possible, the block can be easily manufactured. Furthermore, the belt using the block made of 4,6-nylon has a small amount of wear on the pulley when the belt runs on the pulley, so that it is possible to avoid running instability due to pulley wear. The pulleys can be changed less.

  Moreover, as a reinforcing material mix | blended with this thermoplastic resin, it is preferable to use what combined carbon fiber alone or carbon fiber and an aramid fiber. The carbon fiber is preferably 1 to 60% by mass with respect to the above-described thermoplastic resin. When the amount of carbon fiber is less than 1% by mass, the reinforcing property is insufficient and the strength of the block 2 is insufficient. On the other hand, if it exceeds 60% by mass, the rigidity increases, but the toughness decreases, the bending fatigue resistance and impact resistance decrease, and the noise generated at the time of contact with the pulley increases. The length of the short fiber to be blended can be in the range of 10 μm to 1 mm, and if it is less than 10 μm, the reinforcing effect is reduced for the blended amount, which is not preferable. Moreover, even if an upper limit of more than 1 mm is used, the upper limit is shortened in the course of kneading and forming the raw materials.

  When a whisker-like reinforcing material, which will be described later, is added to this carbon fiber, it is possible to form a block having sufficient strength and the like only with carbon fiber as the fibrous reinforcing material. By adding 5 to 50 mass% with respect to the thermoplastic resin, the toughness of the block is improved, and the wear resistance and impact resistance can be further improved. In this case, when the addition amount of the aramid fiber is less than 5% by mass, the effect of adding the aramid fiber is not sufficiently exhibited. Moreover, when it exceeds 50 mass%, it will become difficult to knead | mix.

  Moreover, you may mix | blend a whisker-like reinforcement material with the said short fiber, and specifically, 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 since it has a tetrapod-like three-dimensional shape as described above, if it is blended with carbon fiber, it will warp during molding. And anisotropy of 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 the addition amount of the zinc oxide whisker is less than 1% by mass with respect to the above-described thermoplastic resin, the added effect does not appear. When the addition amount exceeds 30% by mass, kneading is performed. It cannot be performed and it becomes difficult to mold.

  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), and polyfluorinated alkoxyethylene (PFA). .

  The center belt 3 used as the elastomer 4 is a single material such as chloroprene rubber, natural rubber, nitrile rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, chlorosulfonated polyethylene, alkylated chlorosulfonated polyethylene, or the like. And rubber or polyurethane rubber blended appropriately. And 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 body 5 may be made of a woven fabric, a knitted fabric, a metal thin plate, or the like of the above-mentioned fiber other than a rope embedded in a spiral shape.

  Although not shown, the center belt 3 may be provided with cover canvases on both the upper and lower sides, and examples of the cover canvas include plain fabrics, twill fabrics, satin fabrics, etc. Polyamide fibers such as 6-nylon, 6,6-nylon and 12-nylon, polyvinyl alcohol fibers, polyester fibers and the like.

  Adhesion treatment is performed to laminate and bond the cover canvas having such a configuration to the surface of the center belt. Examples of the adhesion treatment include treatment with an RFL solution, an isocyanate solution, or an epoxy solution. The RFL solution is a mixture of an initial condensate of resorcin and formalin mixed with latex. Examples of latex used here include styrene / butadiene / pyridine terpolymers, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin, and the like. The latex. Further, a pasting process in which a rubber paste dissolved in a solvent is attached to the surface of the cover canvas can be cited as an adhesive process.

  A method for forming a block in which short fibers are oriented in the belt width direction in the vicinity of the boundary between the lower beam and the pillar as described above will be described.

  FIG. 3 is a sectional view of the mold, and FIG. 4 is a front view partially showing the orientation of the short fibers when the gate is arranged only at the center of the upper surface of the upper beam. The mold is divided in the front-rear direction of the block, and is composed of a mold 30 and a mold 31. A combination of the both forms a cavity 32 for molding the block. The resin material is injected with the cavity 32 formed, but the injection gate 33 is provided only at a location corresponding to the center of the upper surface of the upper beam of the block. The mating surfaces 34 of the molds 30 and 31 are arranged in a place slightly removed from the center where the injection gate is located.

  The block 2 is formed by injection molding a resin material containing short fibers using such a mold, and the position of the gate 33 (the position of the downward arrow in the figure) in the mold is the upper beam 11 as described above. It is arrange | positioned in the upper surface center part. The direction of the blended short fibers 41 is determined by the flow of the resin 40 generated in the cavity 32 when the resin material is injected. By setting the flow of the resin 40 to a predetermined flow, the orientation of the short fibers 41 in the lower beam 12 can be set to a desired direction, but the position of the injection gate 32 is set near the upper surface center of the upper beam 11. By arranging them only in the vicinity, the flow of the resin 40 is directed in the belt width direction near the boundary between the lower beam 12 and the pillar 13, and the short fibers 41 can be oriented in the direction close to the belt width direction as shown in FIG. . The vicinity of the center of the upper surface of the upper beam 11 refers to a case where the center of the gate is disposed at a position within a radius of 2.0 mm including the center of the upper surface of the upper beam 11, and the gate is not disposed at the center in a strict sense. However, if it is in said range, it shall be included.

  FIG. 5 partially shows the orientation of the short fibers when the position of the gate 33 of the mold (the position of the upper arrow in the figure) is arranged on the lower beam 12 side. Is oriented in the direction close to the vertical direction of the belt near the boundary between the lower beam 12 and the pillar 13. Compared with this, the position of the gate 33 is clearly arranged at the center of the upper surface of the upper beam 11. It can be seen that the short fibers 41 are oriented at an angle close to the belt width direction in the vicinity of the boundary with the pillar 13.

  In the block 2, the size of the upper beam 11 is larger than that of the lower beam 12 as described above. In order to reduce the occurrence of sink marks and residual stress due to resin shrinkage when molding by injection molding, it is preferable to maintain the injection resin pressure until the injected resin completes cooling and solidification. In order to obtain such a pressure-holding effect, it can be said that it is preferable to increase the size of the gate by disposing the gate 33 on the large beam 11 side.

  Furthermore, the lower beam 12 and the pillar 13 can be formed by providing the mold gate at a position corresponding to the front or rear center of the pillar 13 in the belt traveling direction in addition to the vicinity of the upper surface center of the upper beam 11. Near the boundary, the short fibers 41 can be oriented in a direction close to the belt width direction. In this case, the pressure holding effect of the injection resin pressure is less than that provided in the upper beam 11, but the effect of orienting short fibers is recognized as shown in FIG. 6, and in the vicinity of the boundary between the lower beam 12 and the pillar 13. It is possible to prevent the block 2 from being broken due to the stress concentration. The range near the center here refers to the case where the center of the gate is disposed at a position within a radius of 2.0 mm including the center of the front or rear surface of the pillar 13 in the belt traveling direction. Even if it is not arranged, it is included within the above range.

  The block 2 in which the short fibers 41 are oriented in the direction close to the belt width direction near the boundary between the lower beam 12 and the pillar is formed by injecting the resin material using the mold as described above, cooling, and releasing the mold. Even if stress is concentrated during running of the belt, the stress can be dispersed, and the stress concentration in the direction in which cracks are generated can be relaxed to provide a belt having a long life.

  Next, when manufacturing a block used for the high load transmission belt of the present invention, a comparison is made between an example in which a gate is arranged at the center of the upper surface of the upper beam and emitted from above, and an example in which the gate is arranged at the lower surface of the lower beam and emitted from below For example, based on the fiber orientation predicted by CAE analysis (three-dimensional fiber orientation analysis), stress analysis was performed assuming a load applied to the block when the block running on the belt escapes from the pulley. The belt structure is made of a raw material in which carbon fiber is mixed with 30% by mass of 4,6-nylon and 10% by mass of zinc oxide whisker as resin used for the block. Assuming that chloroprene rubber is used as the elastomer, a belt having a belt pitch width of 18 mm, a pitch circumferential length of 600 mm, and a block pitch of 3 mm is assumed, and the running conditions were analyzed assuming the conditions shown in Table 1. The analysis results are shown in Table 2. Moreover, the stress concentration location by CAE analysis is shown in FIG.

  As can be seen from the results of Table 2, in the injection molding of the block, in the embodiment in which the gate is provided at the position corresponding to the center of the upper surface of the upper beam of the block, the lower beam is compared with the comparative example in which the gate is provided in the lower surface of the lower beam. The value of the maximum stress of the stress concentration generated near the boundary with the pillar is small. It is considered that this is because stress is dispersed by orienting the short fibers in the belt width direction.

  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 principal part perspective view of the high load power transmission belt of this invention. It is a side view of the high load power transmission belt of the present invention. It is sectional drawing of the metal mold | die used for shaping | molding of a block. It is a front view of a block at the time of providing a gate in an upper beam. It is a front view of a block at the time of providing a gate in a lower beam. It is a front view of a block at the time of providing a gate in a pillar. It is a CAE analysis figure of the stress concentration location of a block.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High load power transmission belt 2 Block 3a Center belt 3b Center belt 4 Elastomer 5 Core body 6 Front surface 7 Rear surface 8 Side surface 9 Side surface 11 Upper beam part 12 Lower beam part 13 Center pillar 14 Fitting groove 15 Fitting groove 16 Groove upper surface 17 Groove Lower surface 18 Concave section 19 Concave section 20 Convex section 21 Convex section 30 Mold 31 Mold 32 Cavity 33 Gate 34 Matching surface 40 Resin 41 Short fiber A Near boundary K boundary

Claims (4)

In a center belt in which a core is embedded in an elastomer and a high load transmission belt provided by fitting and mounting a plurality of blocks along the longitudinal direction of the center belt, the block is composed of an upper beam, a lower beam, and an upper and lower beam. It consists of pillars that connect and integrate the centers to form fitting grooves on both sides of the block, and the block is made of a resin material blended with short fibers, near the boundary between the lower beam and the pillar. A high-load transmission belt characterized in that short fibers are oriented at an angle of 45 ° or less with respect to the belt width direction. The high load transmission belt according to claim 1, wherein the resin material constituting the block is any of 4,6-nylon, 9, T-nylon, polyphenylene sulfide, polyether ether ketone, polyether sulfone, and polyamide imide. It consists of a center belt with a core body embedded in an elastomer, and pillars that connect and integrate the centers of the upper beam, lower beam, and upper and lower beams along the longitudinal direction of the center belt. In a block manufacturing method in which a block used for a high-load transmission belt provided by fitting and mounting a plurality of formed blocks is formed by injection molding a resin in which short fibers are blended in a mold, the mold includes an upper portion of the block. A gate is disposed at a position corresponding to the vicinity of the center of the upper surface of the beam or a position corresponding to the vicinity of the center of the pillar, and a block is formed by injecting a resin material from the upper beam side using the mold. A manufacturing method of a block used for a high load transmission belt. The high load transmission belt according to claim 1, wherein the resin material constituting the block is any of 4,6-nylon, 9, T-nylon, polyphenylene sulfide, polyether ether ketone, polyether sulfone, and polyamide imide. The manufacturing method of the block to be used.

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