JP4808475B2 - High load transmission belt - 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 a center belt, and the block.

  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 high-load transmission belt in which the block is fixed to the center belt and the strength in the belt width direction is increased. As a specific configuration, the core is made of an elastomer such as rubber. A block made of a relatively hard elastomer than the elastomer used for the center belt is secured to the center belt embedded in the center belt using a fastening material such as a bolt or a rivet. There is a belt having grooves on both side surfaces of the block, and a pair of center belts fitted into the grooves provided on the side surfaces.

  Such a tension transmission type high load transmission belt has a problem in that friction is always generated between the block and the center belt during running of the belt, and the center belt and the block are deteriorated due to stress concentration and heat generation. In addition, in the case of such a belt, since it is used as a continuously variable transmission as described above, it has a mechanism for shifting by changing the effective diameter of a pulley around which the belt is wound. It will be used with pulley diameter.

  Particularly when the belt is wound around a small pulley diameter, the lower surface side, which is the inner peripheral side of the center belt, is sandwiched between the blocks, stress is concentrated, and a large frictional force is generated, which constitutes the center belt. Deteriorated to cause cracks or cause belt cutting.

  In order to alleviate the concentration of stress applied to the center belt, Patent Document 2 sets so that the upper end of the convex portion provided on the lower surface of the center belt is positioned above the lower end position of the convex portion of the block. A belt has been proposed in which the convex portion of the center belt is not pinched by a block when the belt is wound around a pulley and bent.

  Further, in Patent Document 3, a gap between the block and the center belt is set by setting the curvature radius of the convex portion formed by the block smaller than the curvature radius of the concave portion formed on the inner peripheral surface of the center belt at the portion where the block and the center belt are fitted. A belt is disclosed which is provided with

Japanese Patent Laid-Open No. 63-34342 Japanese Patent Laid-Open No. 62-151646 Japanese Patent Laid-Open No. 9-25999

  By adopting the configuration described in Patent Document 2 and Patent Document 3, friction occurs between the block and the center belt due to the bending of the belt, and stress concentrates on the lower surface of the center belt, causing a crack in the center belt. In addition, it is possible to alleviate the occurrence of problems such as heat generation and melting of the canvas or deterioration of materials such as rubber.

  However, the center belt constrained by the block bends, especially by bending with a small pulley diameter, the friction between the block and the center belt is generated more strongly and heat is generated, and the lower surface is greatly compressed. However, the problem that internal heat generation occurs and leads to wear of the center belt cannot be solved.

  By using a high-strength aramid fiber as the material for the cover canvas as in Patent Document 4, it is possible to solve the problem that the canvas melts and cracks leading to the cutting of the belt. However, it is still insufficient for actual use.

  Therefore, in the present invention, heat generation is prevented by reducing the friction generated between the block and the center belt during belt running, and the generated frictional force is small even when the belt is largely bent with a small pulley diameter. An object of the present invention is to provide a high-load transmission belt that can prevent heat generation and can prevent problems such as cutting of the center belt and can extend the life of the belt.

In order to achieve the above-mentioned problems, according to claim 1 of the present invention, a center belt in which a core is embedded in an elastomer and a cover canvas is laminated on the surface, and a predetermined pitch along the longitudinal direction of the center belt. In the high load transmission belt comprising a plurality of blocks provided, the cover canvas on the lower surface of the center belt is composed of a base fabric made of fibers other than fluororesin and fluororesin fibers, and the fluororesin fibers It is characterized by being laminated and integrated on at least the surface of the base fabric that contacts the block .

The second aspect of the present invention is a high-load transmission belt in which the fluororesin fiber disposed on the cover canvas is a nonwoven fabric and the basis weight is in the range of 10 to 200 g / m ² .

A third aspect of the present invention is a high load transmission belt in which the fluororesin is PTFE resin (tetrafluoroethylene resin).

According to claim 1, the cover canvas provided on the lower surface of the center belt is composed of a base fabric made of fibers other than the fluororesin and a fluororesin fiber, and the fluororesin fiber contacts at least a block of the base fabric. Since the fluororesin fiber has a low friction coefficient, it will not wear even if friction occurs between the center belt and the block, and heat generation will be reduced. It is possible to prevent the problem that the canvas is melted and cut. Furthermore, by providing the base fabric, the strength of the cover canvas can be ensured and the adhesive force with an elastomer such as rubber constituting the center belt can be made sufficient.

  In Claim 2, the fluororesin fiber to be used is a non-woven fabric, and the basis weight thereof is limited to a predetermined range, so that the effect of suppressing wear resistance and heat generation can be raised to a higher level.

In claim 3 , the fluororesin is PTFE resin (tetrafluoroethylene resin), and the effect of suppressing wear resistance and heat generation is high among fluororesins.

  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 sectional view thereof. The high load transmission belt 1 of the present invention is attached to two center belts 3 of the same width formed by embedding a rope-like core body 5 in an elastomer 4 in a spiral shape, and attached to the center belt 3 at a predetermined pitch. It is composed of a plurality of blocks 2. The side faces 6 and 7 of the block have fitting grooves 8 and 9, and the center belt 3 is mounted in the fitting grooves. Both side surfaces 6 and 7 of the block 2 are inclined surfaces that come into contact with the V-grooves of the pulley, receive power from the driven pulley, pull the center belt 3 that is locked and fixed, and drive pulley Is transmitted to the driven pulley. A cover canvas 10 which is a feature of the present invention is laminated and disposed integrally with the center belt 3 on the surface of the center belt 3.

  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. As described above, the fitting grooves 8 and 9 of the center belt 3 are formed, and the groove upper surface and the groove lower surface in the fitting grooves 8 and 9 are formed on the groove 15 and the lower surface provided on the upper surface of the center belt 3. Convex ridges 17 and 18 that engage with the provided concave ridges 16 are provided, and they are engaged with each other by irregularities.

  FIG. 3 is an example of another belt, and a pair of side pillars 22 and 23 extend upward from both ends of the beam portion 21, and the upper ends of the side pillars 22 and 23 respectively extend toward the center of the block 2. The extending lock portions 24 and 25 are provided to face each other. The beam portion 21, the side pillars 22 and 23, and the lock portions 24 and 25 form a fitting groove 20 into which the center belt 3 is fitted. The center belt 3 is inserted into the fitting groove 20 through the opening between the lock portions 24 and 25 and attached. Further, convex portions 27 are respectively provided on the side of the fitting grooves 20 of the lock portions 24 and 25, and the convex portions 27 are fitted to the concave strip portions 26 provided on the center belt 3 at a predetermined pitch. To do. As a result, the center belt 3 is not easily removed from the block 2 after being mounted. A cover canvas 10 is laminated on the surface of the center belt 3 integrally with the center belt 3.

  The cover canvas 10 disposed on both the upper and lower sides of the center belt 3 protects the center belt from friction between the center belt and the block that occurs during belt running. In the present invention, the fluororesin fibers are disposed at least on the side of the cover canvas 10 disposed on the lower surface of the center belt in contact with the block 2. In particular, the arrangement on the lower surface of the center belt that generates a large amount of heat is an indispensable requirement. Of course, not only the lower surface of the center belt but also the cover canvas 10 on the upper surface can be configured in the same manner, and the effects described below can be further improved. It can be said that this is a preferable form. The fiber made of fluororesin itself is a material having a low friction coefficient, and even if it is rubbed with the block 2, it is not easily worn and the heat generated by friction is extremely small. If there is movement between the block and the center belt while the belt is running, the cover canvas on the center belt side will be worn or melted due to heat, resulting in a problem such as cutting the center belt. It was connected. However, placing the fluororesin fiber on the side of the cover canvas that is in contact with the block 2 eliminates the problems of wear and heat generation, and prevents the center belt from being cut due to them, and consequently the belt failure, thus extending the service life. Is something that can be done.

  The fluororesin that can be used as the fluororesin fiber is tetrafluoroethylene resin (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer resin (PFA), tetrafluoroethylene / hexafluoropropylene copolymer Combined resin (PFEP), tetrafluoroethylene / ethylene copolymer resin (PETFE), vinylidene fluoride resin (PVDF), vinyl fluoride resin (PVF), chlorotrifluoroethylene resin (CTFE), ethylene / chlorotrifluoro Examples thereof include ethylene resin (ECTFE) and ethylene / tetrafluoroethylene copolymer resin (PETFE). Among these, it is preferable to use tetrafluoroethylene resin (PTFE) in terms of reducing wear resistance and heat generation. Examples of the form include various forms such as a woven fabric and a non-woven fabric.

Cover canvas 10 is intended for the fluororesin fibers 10b arranged integrally laminated to the surface of the base fabric 10a made of a fiber other than the fluororesin as shown in FIG. 4, the center belt 3 by providing a base fabric 10a The cover canvas 10 can be made of high strength, and the fluororesin generally has poor adhesion, but the fibers constituting the center belt 3 can be formed by using fibers other than the fluororesin as the base fabric 10a. Adhesive strength with the elastomer 4 can be made sufficiently high. In that case, as the base fabric 10a, polyamide fibers such as 6,6-nylon, polyester fibers such as PET, aramid fibers, cotton, and polyparaphenylene benzobisoxazole fibers can be generally used. Can be used. Examples of the canvas composition include plain weaves, twill weaves and satin weaves.

  Although it is lamination | stacking to the base fabric 10a of the fiber 10b made from a fluororesin, it can laminate | stack by the following methods, for example. A fiber having a fiber length of about 5 to 50 mm made of a fluororesin is entangled in a web shape and compressed into a sheet-like nonwoven fabric, which is laminated and integrated in such a manner that it is entangled with the base fabric 10a by hydroentanglement processing. It is possible to obtain a cover canvas 10 in which a non-woven fabric made of a fluororesin is arranged on one side.

When the nonwoven fabric is used for the fluororesin fiber 10b, the basis weight is preferably in the range of 10 to 200 g / m ² . If it is less than 10 g / m ² , the wear resistance tends to be insufficient, and if the belt is run for a long time, the amount of wear increases and the block 2 and the center belt 3 are loosely fitted. When the weight per unit area exceeds 200 g / m ² , the thickness increases and the belt is compressed between the block 2 and the center belt 3 while the belt is running for a long time, reducing the thickness, which also leads to loose fitting. It is not preferable.

  A material used as the elastomer 4 of the center belt 3 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.

  Adhesion treatment is performed to laminate and bond the cover canvas 10 having such a configuration to the surface of the center belt 2. 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 10 can also be cited as an adhesive process.

  In these adhesion treatments, by adding a friction coefficient reducing material to an adhesion treatment agent such as an RFL solution, an isocyanate solution, an epoxy solution, or rubber glue, the friction coefficient between the block 2 and the cover canvas 10 of the center belt 3 is further increased. Wear and heat generation due to friction between the block 2 and the center belt 3 can be prevented in combination with the arrangement of the fluororesin fibers. Specific examples of the friction coefficient reducing material include tetrafluoroethylene resin, ethylene trifluoride resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, and tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin. Fluorine resin such as tetrafluoroethylene-ethylene copolymer resin, ceramic powder, glass beads, ultra high molecular weight polyethylene, graphite, molybdenum disulfide, phenol resin, glass fiber, carbon fiber, aramid fiber, etc. At least one of these, preferably ceramic powder, glass beads, ultrahigh molecular weight polyethylene, graphite, molybdenum disulfide, tetrafluoroethylene resin (PTFE resin) and other fluororesin, phenol resin More preferably ethylene tetrafluoride tree It is preferable to use a fluorocarbon resin (PTFE resin) and the like.

  The block 2 may be made of a resin composition or a reinforcing material having the same shape as that of a block made of metal or the like and having a resin composition coated on the surface. The block with reinforcement is superior in strength and has a stable shape and is not easily deformed even when stressed, but it has the disadvantage of increasing the weight and centrifugal force during belt running. Have On the other hand, the block that does not have a reinforcing material is light in weight, so it has the advantage that the centrifugal force generated during belt running is small and suitable for use at high speeds, but it is easily deformed when stressed. There are disadvantages such as.

  The resin material constituting the block 2 has a relatively large coefficient of friction and excellent wear resistance, and has higher rigidity than the elastomer 4 constituting the center belts 3a and 3b. Specifically, the hardness is 90 ° JIS A or higher. Hard rubber, hard polyurethane resin, liquid crystal resin, thermosetting resin such as phenol resin, epoxy resin, polyester resin, acrylic resin, methacrylic resin, polyamide resin such as 4,6-nylon, 9, T-nylon, polyamide Thermoplastic resins such as imide (PAI) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (PI) resin, polyether sulfone (PES) resin, polyether ether ketone (PEEK) resin are used. It is done.

  Also, in these resins, cotton yarn, woven fabric made of chemical fiber such as polyamide fiber and aramid fiber, glass fiber, metal fiber, carbon fiber, filler, zinc oxide whisker, potassium titanate whisker, aluminum borate whisker, etc. Made of reinforced resin mixed with inorganic materials such as whisker, silica and calcium carbonate.

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

  Reinforcing material is a reinforcing material that provides the side pressure resistance and bending rigidity of block 2, and materials such as aluminum alloy, ceramics, composite material of ceramics and aluminum, carbon fiber reinforced resin and iron are used. Can be mentioned.

In terms of imparting lateral pressure resistance and bending rigidity, a metal material is preferable. Among the metal materials, the elastic modulus of aluminum alloy is 7000 kgf / mm ² and the specific gravity is 2.8, whereas iron has an elastic modulus of 22000 kgf. / Mm ² and a specific gravity of 7.8, and it can be said that iron is stronger in terms of strength. However, for belts that rotate at high speeds, the weight of the belt greatly affects the life of the aluminum, which is advantageous in terms of weight reduction. It is preferable to use an alloy.

  The lower beam of the block 2 must be allowed to be bent so that the belt can be wound around the pulley, and an inclined surface is provided on at least one of the front and rear surfaces in the belt traveling direction. By providing the inclined surface, the belt can be bent without buffering between the blocks.

  In the present embodiment, the case where the two center belts 3 are used and mounted in the fitting groove 20 of the block 2 has been described. However, another center belt may be used. .

  Next, a high load transmission belt according to the present invention is manufactured as shown in Table 1, a belt running test is performed, and the state of the cover canvas on the surface of the center belt after running and the fit between the block and the center belt. The amount of wear of the block (change in the upper width) was measured by observing the degree of looseness.

  The high-load transmission belt used is a block as shown in FIG. 1, and the belt is composed of 30% by mass of carbon fiber with respect to 4,6-nylon and zinc oxide whisker as a block material. The center belt is made of aramid fibers for the core wire and chloroprene rubber for the elastomer, and a belt having a belt pitch width of 18 mm, a pitch peripheral length of 831 mm, and a block pitch of 3 mm. As a cover canvas on the surface of the center belt, a nonwoven fabric made of PTFE is laminated on a base fabric in the examples, and a comparative example is a fabric in which the nonwoven fabric is not arranged, but the detailed configuration is shown in Table 1. What was created by changing was used. And after processing with the solvent adhesive which consists of RFL solution and rubber paste, what was dried at 120 degreeC and heat-processed at 180 degreeC for 2 minutes was coat | covered and arrange | positioned on the surface of the center belt 3. FIG. The high load transmission belts of Examples 1 to 6 and Comparative Examples 1 and 2 were formed according to the configuration of the cover canvas.

  After running the belt for 500 hours under the running conditions shown in Table 2, observe the occurrence of cracks in the center belt cover canvas, and measure the amount of wear (width change) of the block from the belt after running with a projector. did. In addition, the occurrence of looseness between the block and the center belt was confirmed. The above results are summarized in Table 3.

  As can be seen from Table 3, in Examples 1 to 6 in which the PTFE nonwoven fabric was arranged on the surface of the cover canvas, the result was whether the cover canvas was normal except that a slight crack occurred in Example 1 even after running for 500 hours. It has become. Since there is little looseness between the block and the center belt, the wear of the block is also kept small.

  On the other hand, in Comparative Example 1 in which the PTFE nonwoven fabric was not arranged, a large crack was generated, the looseness of the fitting was large, and the wear of the block was the largest at 0.9 mm. This is considered to be caused by the fact that the PTFE fiber was not disposed and the block and the center belt rubbed each other, so that the cover canvas of the center belt was worn and the fitting was loosened.

Furthermore, among Examples 1 to 6, in Example 1 in which the basis weight of the PTFE nonwoven fabric was 5 g / m ² , a small crack was observed in the cover canvas after running for 500 hours, and the fitting was slightly loosened. The wear amount of the block was 0.6 mm, and it was found that the effect was reduced when the basis weight was too small.

  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 a perspective view of the high load transmission belt which shows another example of this invention. It is a principal part side view of a cover canvas.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High load power transmission belt 2 Block 3 Center belt 4 Elastomer 5 Core wire 6 Side surface 7 Side surface 8 Fitting groove 9 Fitting groove 10 Cover canvas 10a Fluororesin fiber 10b Base cloth 11 Upper beam portion 12 Lower beam portion 13 Center pillar 15 Concave line part 16 Concave line part 17 Convex line part 18 Convex line part

Claims (3)

In a high load transmission belt comprising a center belt in which a core body is embedded in an elastomer and a cover canvas is laminated on the surface, and a plurality of blocks provided at a predetermined pitch along the longitudinal direction of the center belt, The cover canvas on the surface is composed of a base fabric made of fibers other than fluororesin and fluororesin fibers, and the fluororesin fibers are laminated and integrated on at least the surface of the base fabric that contacts the block heavy duty power transmission belt characterized in that it. Heavy duty power transmission belt according to claim 1, wherein fluororesin fibers disposed on the cover canvas is in the range is basis weight nonwoven of 10 to 200 g / m ^2. The high-load transmission belt according to claim 1 or 2, wherein the fluororesin is PTFE resin (tetrafluoroethylene resin).

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