JP2004239432A - V-belt for high load transmission and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a V-belt for high load transmission having excellent wear resistance and impact resistance. <P>SOLUTION: The portion of the block bodies 9 formed of a duralumin material of a large number of blocks 8 held by an endless tension band 1 and orderly arranged throughout the overall length thereof at specified pitches which is opposed to at least a pulley groove side part 13, i.e., a phenol resin layer 11 covering a pulley contact surface 14 is formed of a blended resin formed in which a phenol aralkyl resin and a novolak phenol resin are mixed at a weight ratio of 50/50 to 80/20 and also a polyacrylonitrile carbon short fibers with a tensile elastic modulus of at least 300 GPa or higher is mixed alone or together with coal pitch carbon short fibers. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a high-load transmission V-belt and a method of manufacturing the same, and more particularly to a measure for strengthening a block.

  The present applicant has developed a high-load transmission V-belt in which a large number of blocks are engaged and held in an endless tension band and are arranged side by side at a predetermined pitch over the entire length in the belt longitudinal direction (for example, see Patent Document 1). Has been applied to continuously variable transmissions for automobiles and the like. Such a high-load transmission V-belt is used in a so-called wet-type transmission while a metal belt is used in a so-called wet-type transmission in oil as a measure against seizure and wear of a friction surface with a pulley, whereas it is used in a dry-type transmission.

  In addition, as a tension band, a tension band having excellent heat resistance such as hydrogenated NBR reinforced with zinc methacrylate, a core wire, and a canvas has been developed (for example, see Patent Document 2). .

  Further, a technique for increasing the surface roughness of the belt groove of the pulley has been developed in order to reduce noise during belt running (for example, see Patent Document 3).

Also, since the wear resistance and dust resistance of the belt depend on the wear resistance and impact resistance of the resin layer covering the block, an onion structure in novolak phenol resin is used to improve the wear resistance of the resin. A technique has also been developed in which an appropriate amount of carbon short fibers having the following formula is added and, in order to impart impact resistance, short aramid fibers are added (for example, see Patent Documents 4 and 5). Further, in order to control the coefficient of friction with the resin having such a composition, a technique of replacing zinc oxide whiskers with some short carbon fibers and using the same has been developed (for example, see Patent Document 6).
Japanese Patent No. 1441895 (page 3, FIG. 1) Japanese Patent No. 2114341 (page 3, FIG. 1) JP-A-2002-70992 (page 4, FIG. 4) Japanese Patent No. 2857064 (page 3, FIG. 2) Japanese Patent No. 2972104 (page 3, FIG. 2) Patent No. 3172476 (page 3, FIG. 1)

  By the way, even if a heat-resistant rubber is used as in Patent Document 2, since the temperature rises due to self-heating when the belt runs at a high speed, in order to lower the belt temperature below the heat-resistant limit temperature of the rubber, It is necessary to cool the belt by introducing air into the unit. However, dust may be included in the outside air, and when the dust enters the unit, the belt is worn or the resin layer covering the block body is chipped. Therefore, it is conceivable to provide a screen in order to prevent intrusion of dust. However, if the size of the mesh of the screen is too small, the amount of air taken in decreases, and the belt cannot be cooled sufficiently. As described above, the cooling of the belt and the prevention of the intrusion of dust are contradictory, but a belt having as excellent a wear resistance and impact resistance as possible is desired.

  Further, as described in Patent Document 3, even if the surface roughness of the pulley is increased to reduce noise, if it is increased too much, there is a problem that the wear of the belt increases, and it is difficult to control the surface roughness. Accompanied by

  Further, a high-load transmission V-belt called a block belt as described above is employed in a continuously variable transmission for a mini vehicle, and recently, application expansion to 1L-class engines is desired. Such an increase in the engine torque causes an increase in the surface pressure applied to the belt, and it is required to improve the wear resistance of the belt.

  On the other hand, the high-load transmission V-belts configured as described in Patent Documents 4 to 6 do not always have sufficient wear resistance and impact resistance when used at high torque.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a high load transmission V-belt having excellent wear resistance and impact resistance.

  In order to achieve the above object, the present invention is characterized in that the material of the block main body and the resin layer covering the block main body are improved.

  Specifically, the present invention is directed to a high-load transmission V-belt and a method of manufacturing the same, and has taken the following solutions.

  That is, the inventions according to claims 1 to 3 relate to the former high-load transmission V-belt. Among them, the invention according to claim 1 is characterized in that a large number of blocks are held in an endless tension band. The blocks are arranged in parallel at a predetermined pitch over the entire length in the longitudinal direction, and each of the blocks is a high-load transmission V-belt in which at least a portion facing a pulley groove side of a block body made of an aluminum alloy material is covered with a phenol resin layer. The block body is made of a duralumin material, and the phenol resin layer is composed of a phenol aralkyl resin and a novolak phenol resin in a weight ratio of 50/50 or more and 80/20 or less, and has a tensile modulus of at least 300 GPa or more. Of polyacrylonitrile-based carbon short fibers. To.

  According to a second aspect of the present invention, in the first aspect of the present invention, the blended resin constituting the phenolic resin layer is blended with short carbon fibers of coal-based pitch.

  According to a third aspect of the present invention, in the first or second aspect, the block body is made of a duralumin material of JIS H A2024P T361.

  The inventions according to claims 4 to 6 relate to the latter method of manufacturing a high-load transmission V-belt. Among them, the invention according to claim 4 firstly forms a block body made of a duralumin material into a molding die. A phenol aralkyl resin and a novolak phenol resin are blended at a weight ratio of 50/50 or more and 80/20 or less, and a polyacrylonitrile-based carbon short fiber having a tensile modulus of at least 300 GPa is blended. Resin is injected into the cavity to obtain a block in which at least a portion of the block main body facing the pulley groove side is covered with a phenol resin layer, and thereafter, the block is annealed so as not to be overaged, Thereafter, the thus obtained blocks are held in an endless tension band. Characterized by juxtaposed at a predetermined pitch over the belt longitudinal direction the entire length Te.

  The invention described in claim 5 is characterized in that, in the invention described in claim 4, the blended resin constituting the phenol resin layer is blended with short carbon fibers of coal-based pitch.

  The invention according to claim 6 is the invention according to claim 4 or 5, wherein the block main body is made of a duralumin material of JIS H A2024P T361.

  According to the invention according to claims 1 to 6, the block body made of duralumin is blended with a phenol aralkyl resin and a novolak phenol resin in a weight ratio of 50/50 or more and 80/20 or less, and has a tensile modulus of at least 300 GPa or more. Since the polyacrylonitrile-based carbon short fiber alone or coated with a blended resin layer blended with coal-based pitch carbon short fiber, the block body has high strength and excellent heat resistance due to the properties of duralumin. And the wear resistance and impact resistance (dust resistance) of the high-load transmission V-belt can be enhanced by the characteristics of the blend resin layer. In particular, in the invention according to Claims 3 and 6, the strength and heat resistance of the block main body can be further enhanced by the characteristics of the duralumin material JIS H A2024P T361.

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

  1 to 3 show a high-load transmission V-belt A according to an embodiment of the present invention. 1 to 3, reference numeral 1 denotes a pair of endless left and right tension bands, each of which includes a shape-retaining rubber layer 3 mixed with short fibers 2 including at least aramid short fibers and nylon short fibers. The core wire 4 is buried in the shape-retaining rubber layer 3 in a spiral and parallel to the longitudinal direction of the belt. The shape-retaining rubber layer 3 is made of, for example, zinc methacrylate reinforced hydrogenated NBR.

  On the upper surface of the shape-retaining rubber layer 3, a number of upward locking grooves 5 extending in the belt width direction are arranged in parallel at a predetermined pitch over the entire length in the belt longitudinal direction, and also extend on the lower surface in the belt width direction. A large number of downward locking grooves 6 are arranged in parallel at a predetermined pitch over the entire length in the belt longitudinal direction, corresponding to the upward locking grooves 5. Each of the upward locking concave grooves 5 has a substantially semicircular cross-sectional shape, and each of the downward locking concave grooves 6 has a gentle concavely curved cross-sectional shape. 7 are integrally attached.

  A large number of blocks 8 formed in a substantially "H" shape are held in the tension bands 1 in parallel at a predetermined pitch over the entire length in the belt longitudinal direction. Each of the blocks 8 includes a block main body 9 made of an aluminum alloy material formed in a substantially "H" shape by integrally connecting an upper beam 9a and a lower beam 9b with a center pillar 9c. Between the side beam 9b, two engagement grooves 10 are respectively formed in a substantially "U" shape, and by engaging the tension band 1 with these engagement grooves 10, each block 8 is connected to the tension band 1 Is to be held. The block main body 9 is made of a duralumin material having excellent heat resistance and high strength, and is made of an aging treatment material of a metal material made of an aluminum alloy such as alloy numbers 2017, 2014, and 2024 according to JIS standards. In particular, a duralumin material of JIS H A2024P T361 which is more excellent in heat resistance and strength is preferable. Here, "A2024P" represents a rolled material of an aluminum alloy, "2024" represents a metal composition, and "T361" represents that the cross-sectional area reduction rate of "T3" is approximately 6%. . “T3” means that cold working was performed after the solution treatment and further natural aging was performed. The rolled material having this alloy number has such properties that it can sufficiently withstand high temperatures and is hardly softened.

  The block body 9 is integrally coated with a phenolic resin layer 11 except for the middle of the upper surface of the upper beam 9a and the middle of the lower surface of the lower beam 9b, and pulley grooves for the upper beam 9a and the lower beam 9b. A portion facing the side portion 13, that is, a resin layer portion covering both end surfaces in the longitudinal direction is a pulley contact surface 14 that contacts the belt groove side portion 13 of the pulley 12. The block main body 9 only needs to cover at least a portion of the upper beam 9a and the lower beam 9b opposed to the pulley groove side portion 13 (the pulley contact surface 14) with the phenol resin layer 11, and the entire block main body 9 is provided. May be covered with a phenol resin layer 11.

  The phenol resin layer 11 is a blend in which a phenol aralkyl resin and a novolak phenol resin are blended in a weight ratio of 50/50 or more and 80/20 or less, and a polyacrylonitrile-based carbon short fiber having a tensile modulus of at least 300 GPa is blended. It is made of resin. The reason that the weight ratio of the phenol aralkyl resin and the novolak phenol resin is set to be 50/50 or more and 80/20 or less is that when the ratio exceeds 80/20, the curing speed of the resin becomes slow and the characteristics of the resin are sufficiently exhibited. Is too high and causes the block body 9 to soften. On the other hand, if the ratio is less than 50/50, the impact resistance and strength of the resin are reduced, and the effect of improving the wear resistance cannot be expected. The polyacrylonitrile-based carbon short fibers having a tensile modulus of at least 300 GPa are, for example, carbon short fibers having an onion structure with a high degree of graphitization and a large graphite ratio in the fiber cross section. According to this short carbon fiber, the friction coefficient can be reduced, and good mechanical strength and friction and wear characteristics can be maintained even under a high load, as compared with those having a radial structure obtained by a pitch system or the like. Incidentally, when a polyacrylonitrile-based carbon short fiber having a low tensile modulus of elasticity of 245 GPa is used, the coefficient of friction increases with time, and the abrasion increases significantly. In addition, as the carbon short fiber, for the purpose of cost reduction, a coal-based pitch carbon short fiber that does not independently increase the friction coefficient over time with respect to the polyacrylonitrile-based carbon short fiber having a tensile modulus of 300 GPa or more is used. Can be used together. Regarding the amount of the short carbon fiber, 70 to 90 parts by weight with respect to 100 parts by weight of the resin (including the curing agent) has a friction coefficient of 0.23 or less, expresses high strength, and secures workability. Preferred above. In addition, zinc oxide whiskers may be used in combination with polyacrylonitrile-based carbon short fibers to adjust the friction coefficient. Aramid short fibers may be added for imparting impact resistance. In this case, the addition amount of the aramid short fiber is preferably 5 parts or less based on 100 parts by weight of the resin so as not to lower the abrasion resistance. In addition, a solid lubricant such as graphite or molybdenum disulfide may be used as the friction modifier. Further, the method for producing the blended resin (that is, the phenolic resin molding material) in the present invention is not particularly limited. For example, a mixture prepared by mixing the above raw materials at a ratio of the above raw materials is uniformly dispersed and mixed by a Henschel mixer or the like. By kneading the mixture into a sheet and crushing, pulverizing or granulating the obtained sheet material, a moldable blend resin can be obtained.

  On the lower surface of the upper beam 9a, which is the upper surface of each engaging groove 10 of the block body 9, a downward engaging convex portion 15 extending in the belt width direction and engaging with each upward locking concave groove 5 of the tension band 1 projects downward. The upper engaging projection 16 extending in the belt width direction and engaging with the downward locking concave groove 6 of the tension band 1 is also formed on the upper surface of the lower beam 9b which is the lower surface of each engaging groove 10 as described above. It is formed so as to protrude upward corresponding to the downward engagement projection 15. The downward engaging convex portion 15 has a substantially semicircular cross-sectional shape corresponding to each upward locking concave groove 5 of the tension band 1, and the upward engaging convex portion 16 corresponds to each downward locking of the tension band 1. The cross-sectional shape is gently convexly curved corresponding to the concave groove 6. Then, the tension band 1 is engaged with the engagement groove 10 of each block 8 so that the downward engagement projection 15 of each block 8 is engaged with the upward locking recess groove 5 of each tension band 1. The blocks 8 are engaged with the tension bands 1 by engaging the upward engagement projections 16 of the tension members 8 with the downward locking concave grooves 6 of the tension bands 1 so that the blocks 8 are maintained at a predetermined pitch over the entire length in the belt longitudinal direction. They are arranged side by side. In the juxtaposed state, each of the tension bands 1 projects laterally from the pulley contact surface 14 of each block 8 by a predetermined dimension, and as shown in FIG. It is pressed against the side portion 13 and is substantially flush with the pulley contact surfaces 14 on both sides.

  The high-load transmission V-belt A composed of the combination of the block 8 and the tension band 1 configured as described above is wound around the two speed-change pulleys 12 on the driving side and the driven side, and is a belt-type continuously variable. A transmission is constituted so that the pulley contact surface 14 of each block 8 comes into contact with the belt groove side portion 13 of the pulley 12 when the belt runs.

  The high load transmission V-belt A is manufactured as follows. First, a block body 9 made of a duralumin material such as JIS H A2024P T361 as described above is prepared by punching and press-forming, and this block body 9 is set in a cavity of a molding die. Next, a phenol aralkyl resin and a novolak phenol resin are mixed in a weight ratio of 50/50 or more and 80/20 or less, and a polyacrylonitrile-based carbon short fiber having a tensile modulus of at least 300 GPa alone or a carbon of a coal-based pitch is used. The blended resin blended with the short fibers is injected into the cavity, and the block 8 in which at least the pulley contact surface 14 of the block body 9 facing the pulley groove side portion 13 is covered with the phenol resin layer 11 is formed. obtain. Thereafter, the block 8 is annealed so as not to be overaged, so that the phenol resin layer 11 is sufficiently cured. Thereafter, a large number of blocks 8 thus obtained are held in a pair of endless tension bands 1 and are arranged side by side at a predetermined pitch over the entire length in the belt longitudinal direction, so that the high-load transmission V-belt A is obtained. obtain.

  Next, examples of the present invention will be described together with comparative examples as experimental results.

  In both of the examples and the comparative examples, the block body 9 was formed by stamping and pressing a duralumin material of JIS H A2024P T361, and the block body 9 was coated with a phenolic resin layer 11 by injection molding and annealed. The conditions are shown in Tables 1 and 2 below. Then, a large number of blocks 8 thus obtained were assembled into the tension band 1 to obtain a high-load transmission V-belt A. The pitch width of the block 8 (the width of the block at the position of the core line) is 25 mm, the thickness of the block 8 is 2.95 mm, the belt length is 612 mm, and the blocks 8 are mounted at a pitch of 3 mm. High-speed durability, block wear and dust resistance were observed. The characteristics of the resin were evaluated by a conventional method by measuring the coefficient of friction and the specific wear amount at 120 ° C. flexural modulus, 120 ° C. flexural strength, IZOD impact strength, and Suzuki friction and wear tester. The results are shown in Tables 1 and 2 below. In Tables 1 and 2, the carbon fiber A is a polyacrylonitrile-based carbon short fiber having a tensile modulus of at least 300 GPa, for example, an onion-structured carbon short fiber having a high degree of graphitization. The carbon fiber B is a carbon-based short carbon fiber.

In obtaining the data, a high-speed durability test of the high-load transmission V-belt A was performed using a high-speed durability device shown in FIGS. 4 (a) and 4 (b). This high-speed endurance device includes a heat-resistant box 19 having a hot-air inlet 17 formed on a side surface and a hot-air outlet 18 formed on an upper surface. A pitch circle diameter 139 fixed to a drive shaft 20 is provided in the heat-resistant box 19. A 0.8 mm drive pulley 12A and a driven pulley 12B having a pitch circle diameter of 70.8 mm fixed to the driven shaft 21 are spaced apart from each other. The V-belt A for high load transmission of each of the examples and the comparative example is wound around the driving pulley 12A and the driven pulley 12B, and hot air of 107 ° C. is sent into the heat-resistant box 19 from the hot air inlet 17 at a flow rate of 20 mm ³ / min. The high load transmission V-belt A was driven at a drive shaft torque of 75.5 N · m, a drive shaft rotation speed of 5190 rpm, and a shaft load (DW) of 2349 N while discharging it from the hot air outlet 18.

  A dust durability test of the high load transmission V-belt A was performed using a dust durability device shown in FIG. In this dust durable apparatus, a dust input section 23 is provided on the upper surface of a dust box 22. Inside the dust box 22, a drive pulley 12 A having a pitch circle diameter of 120 mm fixed to a drive shaft 20 and a driven shaft 21 The driven pulley 12B having a pitch circle diameter of 60 mm is spaced apart from the driven pulley 12B. The high load transmission V-belt A of each embodiment and the comparative example is wound around the driving pulley 12A and the driven pulley 12B, and 0.3 g of 240-mesh silica sand is injected into the dust box 22 from the dust input unit 23 every hour. The V-belt A for high-load transmission is run at a drive shaft torque of no load, a drive shaft rotation speed of 1800 rpm, and a shaft load (DW) of 1490 N. Was observed.

  As a result, as shown in Tables 1 and 2 below, when the weight ratio of phenol aralkyl resin / novolak phenol resin was increased and the annealing temperature was increased, the high-temperature physical properties, impact resistance and abrasion resistance of the resin were improved. It can be seen that the block wear and dust resistance of the high load transmission V-belt A are improved. In Comparative Example 2 in which the weight ratio of phenol aralkyl resin / novolak phenol resin was 40/60, the strength improvement effect was small, but Example 1 in which the weight ratio of phenol aralkyl resin / novolak phenol resin was 50/50. It can be seen that a clear strength improving effect is observed. Furthermore, in Comparative Example 3 in which the weight ratio of phenol aralkyl resin / novolak phenol resin is 100/0, a considerably high-temperature annealing treatment (200 ° C.) is required. It can be seen that the block is overaged, the heat resistance of the aluminum alloy is impaired, and the durability of the high load transmission V-belt A is reduced. Therefore, the upper limit of the weight ratio of the phenol aralkyl resin / novolak phenol resin is 80/20, and up to this point, it is possible to make the wear resistance and the impact resistance compatible without overaging the aluminum alloy. It can be seen that a high-load transmission V-belt with high durability can be obtained.

  INDUSTRIAL APPLICABILITY The present invention is useful as a high-load transmission V-belt applied to a continuously variable transmission for automobiles and the like and a method of manufacturing the same.

It is a perspective view of a V belt for high load transmission. It is a side view of the V belt for high load transmission. FIG. 3 is a sectional view taken along line III-III in FIG. 2. Fig. 3 shows a high-speed durability test apparatus, wherein (a) is a plan view and (b) is a front view. It is a front view of a dust durability test apparatus.

Explanation of reference numerals

1 Tension band 8 Block 9 Block body 11 Phenol resin layer 13 Pulley groove side 14 Pulley contact surface (part facing pulley)
A V belt for high load transmission

Claims (6)

A large number of blocks are held in an endless tension band and are arranged side by side at a predetermined pitch over the entire length in the belt longitudinal direction, and each of the blocks is a phenol resin at least in a portion facing a pulley groove side of a block body made of an aluminum alloy material. A high-load transmission V-belt coated with a layer,
The block body is made of duralumin material,
The phenol resin layer is a blend resin in which a phenol aralkyl resin and a novolak phenol resin are blended in a weight ratio of 50/50 or more and 80/20 or less, and a polyacrylonitrile-based carbon short fiber having a tensile modulus of at least 300 GPa is blended. A high-load transmission V-belt comprising: The high-load transmission V-belt according to claim 1,
A high-load transmission V-belt, characterized in that carbon-short fibers of coal pitch are blended in a blend resin constituting the phenol resin layer. The high load transmission V-belt according to claim 1 or 2,
A high load transmission V-belt, wherein the block body is made of a duralumin material of JIS H A2024P T361. Set the block body made of duralumin material in the cavity of the mold,
Next, a blend resin containing a phenol aralkyl resin and a novolak phenol resin in a weight ratio of 50/50 or more and 80/20 or less and a polyacrylonitrile-based carbon short fiber having a tensile modulus of at least 300 GPa is mixed with the cavity. A block in which at least a portion of the block body facing the pulley groove side portion of the block body is covered with a phenol resin layer,
After that, the above block is annealed so as not to be overaged,
Thereafter, a plurality of blocks obtained in this manner are held in an endless tension band, and are arranged side by side at a predetermined pitch over the entire length in the belt longitudinal direction. The method for manufacturing a V-belt for high load transmission according to claim 4,
A method for producing a high-load transmission V-belt, characterized in that carbon-short fibers of coal-based pitch are blended in a blend resin constituting a phenol resin layer. The method for manufacturing a high-load transmission V-belt according to claim 4 or 5,
A method for manufacturing a high-load transmission V-belt, wherein the block body is made of a duralumin material of JIS H A2024P T361.

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