JP4435617B2 - Manufacturing method of high load transmission belt - Google Patents

Description

  The present invention relates to a high load transmission belt manufacturing method and manufacturing apparatus and a high load transmission belt in which a plurality of blocks are fixed along the longitudinal direction of a tension band, and can be efficiently manufactured in a shorter time. It is related to things that are less prone to problems such as cracking.

  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 those used as such belts, there is a tensile transmission type high load transmission belt in which the block is fixed to the center belt (tensile belt) and the strength in the belt width direction is increased. As a specific configuration, A block made of elastomer that is relatively harder than the elastomer used for the center belt (tension belt) is secured to the center belt with a core wire embedded in an elastomer such as rubber using a fastening material such as a bolt or rivet. There is something fixed.

  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 Japanese Patent Application Laid-Open No. 63-34342. 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.

  For this reason, for example, since the belt disclosed in Patent Document 2 uses an aluminum alloy or the like as an insert material, if it rotates at a high speed, a large centrifugal force is applied due to its weight, and a large tension acts on the belt. As a result, there has been a problem that the belt is prematurely damaged.

  In addition, the amount of heat generated between the pulley and the block increases due to the high-speed rotation. Therefore, in the block mainly composed of phenolic resin as disclosed in Patent Document 1, the phenolic resin is inferior in impact resistance. However, the belt may be damaged. Unless this was improved, the above-described demand for a high load transmission belt could not be satisfied at a high level. In addition, since the phenol resin is a thermosetting resin, there is a problem that the molding cycle becomes long and the recyclability is inferior.

  Therefore, it is conceivable to use a block made of a thermoplastic resin material without inserting an insert made of an aluminum alloy or the like embedded in the block in order to reduce the weight of the block.

  Patent Document 3 discloses a belt manufacturing method in which a block is formed by injection molding in a state where a center belt (tension band) is installed in a mold.

Japanese Examined Patent Publication No. 7-110900 Japanese Patent Laid-Open No. 63-34342 JP 2003-202054 A

  However, the production of a belt equipped with such a block requires an operation of fitting the blocks one by one in a tension band, which is very laborious to produce. This is disadvantageous in terms of manufacturing cost, and there is a problem that the belt becomes expensive.

  Moreover, in patent document 3, the process of mounting a block separately formed on the center belt (tension band) can be omitted by injecting resin into a mold having a center belt (tension band) and molding the block. Therefore, the manufacturing cost can be greatly reduced.

  However, when such a square block is formed by injection molding in the cavity, a weld line is formed at a position opposite to the injection gate at the time of molding. It can be said that this weld line is a weak portion in terms of physical properties such as strength in the entire molded body. On the other hand, in the case of the belt having such a structure, the lower beam portion in the block is a portion where the tension is always applied from the tension band, and the portion is smaller in dimension than the upper beam portion, and is easily damaged. It can be said that.

  If the weak points generated for these molding reasons overlap with the weak points on the structure of the belt, the problem is more likely to occur, and the belt may reach the end of its life early.

  Therefore, in the production of a belt of such a type in which such a block is attached to a tension band, the present invention makes it very easy to perform high load transmission in a short time by simultaneously forming the block and attaching the block to the tension band. It is an object of the present invention to provide a method for manufacturing a high-load transmission belt that can manufacture a belt and that does not easily cause cracks or the like by dispersing causes that are weak points of the block.

  In order to solve the above-mentioned problems, claim 1 of the present invention is a method of manufacturing a high-load transmission belt provided with a tension band and a plurality of blocks along the longitudinal direction of the tension band. Has a tension band holding part and a cavity for molding a block arranged so that the molded block is fitted in a predetermined position of the tension band held by the tension band holding part. A high-load transmission belt for molding a block having upper and lower beam parts and left and right sliding parts and simultaneously attaching the block to the tension band by injecting resin into a cavity in the mold in a state where the belt is set on the tension band holding part In this manufacturing method, the injection gate for injecting the raw material into the mold is arranged at the position of the lower beam portion of the block.

  Because the weld line is formed on the opposite side of the block by placing the injection gate at the position of the lower beam part that tends to be a weak point in the block, the reason for molding in the lower beam part There is no overlap between the weak points generated in the block and the weak points in the block structure.

  FIG. 1 is a perspective view showing an example of a mold used in the method for manufacturing a high load transmission belt according to the present invention, and FIG. 2 is a front view of the mold as viewed from the opened state. FIG. 3 is a perspective view showing an example of a high load transmission belt manufactured by the manufacturing method of the present invention, and FIG. 4 is a side sectional view of the high load transmission belt. 5 and 6 are front views of the block showing the position of the injection gate, FIG. 7 is a side cross-sectional view seen with the mold closed, and FIG. 8 is a side cross-sectional view showing another example in FIG. is there.

  The high load transmission belt manufactured by the manufacturing method of the present invention is, for example, as shown in FIGS. 3 and 4, and the high load transmission belt 1 has a core wire 5 embedded in an elastomer 4 in a spiral shape. And a plurality of blocks 2 that are fitted in recesses 6 formed at a predetermined pitch on the upper surface of the tension band 3 and are locked and fixed. Both side surfaces 2a and 2b of the block 2 are inclined surfaces that engage with the V-grooves of the pulley, and receive power from the driven pulley to pull the tension band 3 that is locked and fixed. The power of the driving pulley is transmitted to the driven pulley.

  In the block 2, as shown in FIG. 3, the upper beam portion 11 and the lower beam portion 12, and both side portions 13 and 14 are integrally formed around the tension band 3. The center of the block 2 has an opening 15 into which the tension band 3 is fitted. The upper surface and the lower surface in the opening 15 have a groove 6 provided on the upper surface of the tension band 3 and a groove 7 provided on the lower surface. Convex ridges 16 and 17 are formed to be engaged with each other.

  In manufacturing a high-load transmission belt in which a tension band is fitted into a block in this way, a pair of molds 30 and 31 are used as shown in FIGS. Has a tension band holding part 32 and a cavity 33 for forming the block 2 in a state where the pair of molds 30 and 31 are joined together. The resin is injected into the cavities 33 in the molds 30 and 31 in the state of being set. The tension band 3 has recesses 8 and 9 for fitting with the tension band holding part 32 of the mold between the recesses 6 and 7 for fitting with the block 2 on the upper and lower surfaces, and the block 2 is injection molded. The tension band 3 is positioned at the time of molding.

  The cavity 33 is arranged so as to surround the tension band 3 with the tension band 3 fitted in the tension band holding part 32. When the block 2 is formed by the cavity 33, the block 2 is formed in the tension band 3 with the concave strip portion 6, 7 is formed in a state of being fitted.

  In the present invention, the injection gate 35 for injecting the raw material of the block 2 into the cavity 33 is disposed at the position of the lower beam portion 12 of the block 2. When such a B-shaped molded body is formed, a weld line is formed in which the injected resins collide with each other on the side opposite to the position of the injection gate 35. The weld line becomes a weak point portion having weak physical properties such as strength in the molded body. On the other hand, when the block belt having such a structure is run, the tension from the tension band is almost applied to the lower beam portion 12 of the block 2, and from the structural aspect of the belt, the lower beam portion 12 is It can be said that it is a part which is more easily damaged than other parts and is likely to cause a failure.

  In the present invention, by disposing the defect of the weld line generated at the time of molding other than the lower beam portion 12 which is a place where damage is easily caused due to the structure of the belt, the portion that causes the block to be weakened is dispersed. As a result, problems such as cracks can be prevented from occurring. In the present invention, by arranging the injection gate 35 at the position of the lower beam portion 12 as described above, the weld line can be brought to the upper beam portion 11 that hardly receives tension from the tension band. It is possible to reduce problems such as block breaks.

  Through the steps as described above, the block 2 can be attached to the tension band 3 at the same time as the block 2 is molded.

  Conventionally, in the manufacture of such a high load transmission belt, the tension band 3 is manufactured, and the block 2 is manufactured separately, and then the block 2 is fitted into the tension band 3 one by one. Although much time has been taken for the work of fitting the block 2 into the tension band 3, since the block 2 is formed at a predetermined position of the tension band 3 by adopting the above manufacturing method, When the block 2 is completely formed, the block 2 is fitted into the tension band 3, so that the work of fitting the block 2 into the tension band 3 is not required, so that the time required for manufacturing is greatly reduced. Is something that can be done.

  The position of the emission gate 35 is one that emits from the lower direction near the center of the lower beam portion 12 of the block 2 as indicated by the arrow in FIG. 5, and the weld line W can be formed near the center of the upper beam portion 11, In addition, as shown in FIG. 6, it is also possible to provide at the end of the lower beam portion 12 and at a position where the beam exits from the side. In this case, the weld line W can be formed near the end of the upper beam portion 11. By arranging the injection gate 35 at the position as shown in FIG. 6, it has a mold dividing surface as shown in FIG. 8, which will be described later, and can cope with the case where the gate 35 cannot be arranged at the center of the lower beam 12. It is.

  Further, as shown in FIG. 7, the mold 30 and the mold 31 have a dividing surface 36 positioned so that a parting line is formed at the center of the upper beam portion 11 and the lower beam portion 12 of the block. By doing so, the side surfaces 2a and 2b of the block that come into contact with the pulley when the belt travels can be finished to a smooth surface, so that the problem of noise and wear in the initial belt travel can be solved.

  The position of the dividing surface 36 is located near the center of the tension band 3 in FIG. 7, but if the side surfaces 2a and 2b of the block are finished smoothly, it will be at the end of the tension band 3 as shown in FIG. It is also possible to position it. By doing so, the tension band 3 does not protrude from the mold 31 in a state where the tension band 3 is inserted into the mold 31, so the tension band 3 that protrudes when the mold 30 is aligned is bent or caught by the mold. Therefore, it can be said that it is a preferable form.

  In the example shown in FIG. 2, the cavities 33 provided in the molds 30 and 31 are five, and the number of blocks that can be molded at one time is five. Therefore, after forming five blocks, the belt is once removed from the mold, and the five blocks are rotated in the direction of the arrow in FIG. And 5 blocks 2 are formed at the next position. By repeating such an operation, the entire block 2 around the belt is molded to complete the belt.

  The tension band does not need to be fixed in places other than the cavity 33 for molding the block 2, and a passage 34 that is slightly wider than the general shape of the belt is formed as a belt escape location when the mold is closed.

  When the molding of the block is completed, the molds 30 and 31 are opened, and the block 2 is removed from the mold. For removal, it is convenient to use an eject pin protruding from the mold. For example, as shown in the block of FIG. 9, the vertical surface portion 2c is formed at the vertical positions of the inclined side surfaces 2a and 2b of the block 2. It is good also as a location where an eject pin contacts.

  In such a high load transmission belt 1 in which the block 2 is attached to the tension band 3, the pitch of the block 2 (interval between the blocks 2 attached to the tension band 3) is related to noise problems and the pitch is too large. And noise will increase. However, on the other hand, if the thickness of the molds existing between the blocks when the blocks 2 are formed becomes too thin, the molds are deformed by the injection pressure, leading to deformation of the blocks 2, which is not preferable. Therefore, the thickness of the mold between the block 2 and the block 2 is set to 1/6 to 3/2 of the thickness of the block 2. However, as shown in FIG. 2, in some cases, such as the number of blocks formed at one time out of all the blocks of the high load transmission belt 1, it is more preferably 1/2 to 3/2.

  If the thickness of the mold between the block 2 and the block 2 exceeds 3/2 of the block thickness, the pitch of the block becomes too large, causing problems of belt strength and noise. Mold deformation will occur.

  In the above description, the block 2 is formed by molding 5 pieces at a time, and all the blocks are formed in order to complete the high load transmission belt 1. However, a mold having the same number of cavities as the total number of the blocks 2 is used. You may mold all at once.

  When the mold is provided with the same number of cavities 33 as the total number of blocks, and all the blocks 2 are molded at once, the cavities 33 are all located next to each other, and the pressure in the cavities 33 is substantially constant. Therefore, even if the thickness of the mold between the blocks 2 is small, the mold is hardly deformed. Therefore, the block can be sufficiently formed in the range of 1/6 to 1/2 of the block thickness.

  The high load transmission belt applicable to the present invention is not limited to the example shown in FIG. 3 and can take various forms. The belt shown in FIG. 10 has substantially the same shape as the belt shown in FIG. 3, but has through holes 18 at the same pitch as the block attached to the center of the tension band 3 in the width direction. The resin is connected 19 through the through hole 18 when the resin is molded.

  Thus, the resin 19 that forms the block is connected through the through-holes 18 provided in the tension band 3 so that the fixing force between the block 2 and the tension band 3 becomes stronger. If the belt 1 continues to run for a long period of time, the block 2 and the tension band 3 will rattle, causing the noise of the belt 1 to increase, the block 2 to be damaged, and the tension band 3 to be cut off. Although it may lead to failure, the life of the belt 1 can be extended by increasing the fixing force of the block 2 and the tension band 3.

  In the example of FIG. 10, the number of the through holes 18 provided in the tension band 3 per block 2 is one, but the number is not limited to one, and a plurality of holes such as two or three are provided. It is also possible to provide.

  This block 2 is made of only a synthetic resin material, and no insert material made of metal such as aluminum alloy is embedded therein. However, the insert material made of metal or the like here refers to a skeleton-like material that has almost the shape of a block.For example, a reinforcing material such as a short fiber or whisker that is added in a synthetic resin material is added. The addition does not depart from the scope of the present invention.

  As the block resin, polyamide resin, polyamideimide (PAI) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (PI) resin, polyethersulfone (PES) resin, Synthetic resins such as polyetheretherketone (PEEK) resin are used, but among them, they have low friction coefficient, excellent wear resistance, rigidity and elasticity against bending, and can be easily damaged. Resin which does not end up is good, and it can be said that polyamide resin, especially nylon 46 is preferable.

  In the present invention, it is possible to mix a fibrous reinforcing material and a whisker-shaped reinforcing material in the synthetic resin forming the block as described above, and the fibrous reinforcing material is blended in the range of 15 to 40% by weight. To do. If it is less than 15% by weight, there is a problem that the reinforcing effect is small and the wear resistance of the block is not sufficient, and if it exceeds 40% by weight, it becomes difficult to blend into a resin or injection molding becomes difficult. This is not preferable.

  Examples of the fibrous reinforcing material to be blended with the synthetic resin include aramid fibers, carbon fibers, glass fibers, polyamide fibers, and polyester fibers. Among them, by using a combination of nylon 46 and carbon fiber, which is a preferable example of the resin constituting the block, the carbon fiber can improve the water absorption defect of nylon 46 and greatly improve the rigidity. In addition, the wear resistance, impact resistance, and fatigue resistance of nylon 46 can be utilized. Of the carbon fibers, PAN-based carbon fibers are preferably used. Moreover, the toughness of a block improves by mix | blending an aramid fiber in combination with a carbon fiber, and abrasion resistance and impact resistance can be improved further.

  Here, the PAN-based carbon fiber used has good compatibility with the thermoplastic resin, and the carbon fiber used preferably has a length of 1 to 5 mm. If it is less than 1 mm, the block is not sufficiently reinforced, and if it exceeds 5 mm, kneading with the resin becomes difficult, and it is not preferable because it breaks and shortens during kneading.

  Moreover, you may mix | blend inorganic fibers, such as a zinc oxide whisker, a potassium titanate whisker, an aluminum borate whisker other than said organic fiber as said fibrous reinforcement. By blending these whiskers, warpage during molding and anisotropy of molding shrinkage are improved. Further, 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.

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

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

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

  Examples of the elastomer 4 used for the tension band 3 include a single material such as chloroprene rubber, natural rubber, nitrile rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, or a rubber or polyurethane rubber obtained by appropriately blending them. . As the core 5, a rope selected from polyester fiber, polyamide fiber, aramid fiber, glass fiber, steel wire and the like is used. The core wire 5 may be made of a woven fabric, knitted fabric, metal thin plate, or the like of the above-mentioned fiber other than a rope embedded in a spiral shape.

  The block used in the high load transmission belt according to the present invention is not limited to the form shown in the present embodiment.

  Next, a belt (Example 1) prepared by the manufacturing method of the present invention and a belt (Comparative Example 1) prepared by a method deviating from the present invention were run, and the time until failure occurred was measured.

  As Example 1, a high load transmission belt as shown in FIG. 3 is formed using a forming apparatus as shown in FIG. 1 and the injection gate is located at the center of the lower beam portion as shown in FIG. Made a belt. The resin material used for the block is 46 nylon containing 30% by mass of carbon fiber, and the pitch of the block is 6 mm. A durability test was performed by running the belt under the conditions shown in Table 1. The results are shown in Table 2.

  In Example 2, a belt was produced in the same manner as in Example 1 except that the position of the injection gate was arranged at the end of the lower beam part as shown in FIG. A durability test was performed by running the belt under the conditions shown in Table 1. The results are shown in Table 2.

Comparative Example 1

  As Comparative Example 1, a belt was produced in the same manner as in Example 1 except that the position of the injection gate was arranged at the end of the upper beam portion. A durability test was performed by running the belt under the conditions shown in Table 1. The results are shown in Table 2.

  As can be seen from the results in Table 2, the comparative example 1 in which the injection gate when forming the block is arranged near the end of the upper beam portion and the weld line is in the lower beam portion has a failure early. In the first and second embodiments in which the position of the injection gate is arranged at the position of the lower beam portion of the block and the weld line is brought to the position of the upper beam portion, the weld line is moved to the upper beam without causing a failure even after running for 400 hours. It can be seen that belt failure due to block breakage or the like is less likely to occur by bringing it to the part.

  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 general | schematic perspective view of the manufacturing apparatus used with the manufacturing method of this invention. It is the front view seen from the place which opened the metal mold | die. It is a perspective view of the high load power transmission belt manufactured by the manufacturing method of this invention. It is a sectional side view of a high load power transmission belt. It is a front view which shows the position of the injection gate in a block. It is a front view which shows the position of another injection gate in a block. It is the sectional side view seen in the state where a metal mold was closed. It is a sectional side view which shows another example in FIG. It is a front view which shows another example of a block. It is a perspective view which shows another example of a high load power transmission belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High load transmission belt 2 Block 3 Tension band 4 Elastomer 5 Core wire 6 Concave part 7 Concave part 8 Concave part 9 Concave part 11 Upper beam part 12 Lower beam part 30 Mold 31 Mold 32 Tension band holding part 33 Cavity 34 Passage 35 Gate 36 Split surface

Claims (1)

A method of manufacturing a high load transmission belt having a tension band and a plurality of blocks along the longitudinal direction of the tension band, wherein the mold includes a tension band holding part and a tension band held by the tension band holding part The mold has a cavity for molding the block arranged so that the molded block is fitted at a predetermined position, and the resin is placed in the cavity in the mold in a state where the tension band is set in the tension band holding portion. In the manufacturing method of the high load transmission belt in which the block having the upper and lower beam portions and the left and right sliding portions is molded and at the same time the block is attached to the tension band, the injection gate for injecting the raw material into the mold is formed in the block. A method for manufacturing a high-load transmission belt, wherein the belt is disposed at a position of a lower beam portion.

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