JP2003191334A - Method for connecting reinforcing cloth of center belt for high load transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate an adverse influence of the presence of a connector to a running performance, a noise and a lifetime of a belt since there is not a considerable difference in an elongation and bendability of the connector, as compared with those of other part as a temporary fixing of a reinforcing cloth is fusion bonded only at a limited part of an entire width of the belt. <P>SOLUTION: A method for connecting the reinforcing cloth of a center belt is used for a high load transmission belt having a plurality of engaged fixed blocks, along a longitudinal direction of the center belt covered on at least upper or lower one side surface with the cloth and a rubber adhered to the surface of the cloth 15. The method comprises the steps of partly heat fusion bonding 17 to temporarily fix the ends of the cloth in a superposed state before the center belt is vulcanized, thereafter heating and pressurizing to crosslink the rubber adhered to the surface of the cloth to connect the entire width of the cloth. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high load transmission belt used for applications such as continuously variable transmissions such as automobiles, motorcycles, agricultural machinery, etc., in which blocks are arranged in a longitudinal direction on a center belt. The present invention relates to a method for manufacturing a center belt, which is capable of improving the accuracy of the position of the core body in the center belt and the size and shape of the portion where the center belt and the block are fitted together.

[0002]

2. Description of the Related Art A belt used in a belt type continuously variable transmission is used by being wound around a variable speed pulley in which the effective groove diameter of the pulley is changed by changing the V groove width of the pulley to adjust the gear ratio. However, since the lateral pressure from the pulley increases, the belt must withstand the large lateral pressure. Further, in addition to the use of continuously variable transmission, it is necessary to use a belt that can withstand a particularly high load for a high load transmission application in which the life of a normal rubber belt is too short.

Among such belts used is a high-load transmission belt in which a block is fixed to a center belt to increase the strength in the belt width direction. As a concrete structure, a core is made of rubber or the like. No. 63-34342, in which a block relatively harder than the rubber used in the center belt is fixed and fixed to the center belt embedded in the rubber by using a fastening material such as bolts and rivets. As shown, there is a belt which has grooves on both side surfaces of the block and in which a pair of center belts are fitted in the grooves provided on the side surfaces.

In such a belt, upper and lower surfaces of the center belt are covered with a reinforcing cloth such as canvas for reinforcement. When manufacturing the center belt, the reinforcing cloth is wound so as to be overlapped with the unvulcanized rubber sheet, and it is necessary to join the end portions to each other to make the endless state.

For example, Japanese Unexamined Patent Publication No. 9-26000 discloses a belt used in a belt transmission such as a belt type continuously variable transmission, in which a large number of blocks are locked in the longitudinal direction of a tension band provided with a locking portion. In the fixed high load transmission V-belt, the end portion of the reinforcing cloth covering the lower surface of the tension band should be jointed in advance in an abutted state, and the butt joint portion should be biased in the belt width direction. It is disclosed to arrange and to join such that the ends of the butt joint are sewn together.

It is an object of the present invention to improve the durability by avoiding the trouble caused by the lamp at the joint between the ends of the canvas.

Further, Japanese Patent Application Laid-Open No. 11-325191 discloses that in the tension band of a similar high load transmission V-belt, the ends of the reinforcing cloth are lap-jointed with a lap margin of 1 mm or less.

This is a butt joint, which prevents the problem that rubber is exposed from the gap between the joints and cracks easily occur, and suppresses the increase in thickness caused by overlapping the ends as much as possible. The purpose is to eliminate the problem that the block swings.

On the other hand, when the reinforcing cloth is wound when manufacturing the center belt, the reinforcing cloth is wound around the mold or the unvulcanized rubber sheet, and if necessary, other materials may be wound from above. It was sulfur. Since rubber is attached to the reinforcing cloth, when the reinforcing cloths are superposed, the ends of the reinforcing cloths are joined when the rubbers are vulcanized. However, it is necessary to fix it by some means until it is vulcanized.

As a method of fixing, a method of sticking by utilizing the adhesiveness of unvulcanized rubber, a method of sewing with a sewing machine, a method of heating the entire width of the reinforcing cloth with a hot plate or the like to melt and heat-bond it. Method etc. are mentioned.

[0011]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-26000
According to the joint method as disclosed in Japanese Patent Publication, since the reinforcing cloth is jointed in advance, the tubular reinforcing cloth is placed on the mold or on the unvulcanized rubber sheet wound around the mold. It is necessary to cover it, and it will give a little dimensional margin. If you give too much room, it will be easier to cover it with the reinforcing cloth, but there is a problem that it may cause rattling of the blocks or the performance of the belt, and if the room is too small, it will not affect the belt. There is a problem that the work of covering the reinforcing cloth becomes difficult although the number decreases.

Further, the joint portion of the reinforcing cloth is generally inferior in flexibility and less stretched than the portion other than the joint. If the joint portion is arranged in a bias with respect to the width direction of the belt, for example, the proportion of the joint portion in the longitudinal direction of the belt becomes large, and a portion different in elongation and flexibility is formed over a wide range. When unevenness that engages with the blocks on the upper and lower surfaces is formed, the difference in elongation causes resistance and the uneven shape is difficult to appear, and the influence on the running of the belt also increases, increasing noise and shortening the life. It also leads to things such as becoming.

Japanese Unexamined Patent Publication (Kokai) No. 11-325191 discloses the content of a joint of a reinforcing cloth, but does not disclose anything about jointing.

Further, regarding the method of fixing the reinforcing cloth before vulcanization, the method of utilizing the adhesiveness of unvulcanized rubber is convenient, but the adhesiveness may be small depending on the rubber, and the certainty is poor. If the reinforcing cloth is not fixed and a gap is created between the short parts, the rubber will stick out from the gap and become defective.

In the method of sewing using a sewing machine and the method of fusing the entire width of the reinforcing cloth and heat-sealing the same, the stretch and bendability of the canvas at that part are different from those of the other parts, and the upper and lower surfaces of the center belt. When forming the unevenness to be engaged with the block, there is a problem that the difference in elongation or the like causes resistance and the uneven shape is difficult to appear.

Therefore, the present invention is to provide a method for manufacturing a center belt in which a joint portion of a reinforcing cloth for a center belt is joined by a joint method in which a difference between the joint portion and a portion other than the joint is small. And

[0017]

In order to achieve the above object, a center belt having a core body embedded in rubber and a plurality of blocks fitted and fixed along the longitudinal direction of the center belt are provided. A center belt used for a high load transmission belt, wherein a reinforcing cloth is attached to at least one of upper and lower surfaces of the center belt in a reinforcing cloth joining method, wherein a rubber is attached to the surface of the reinforcing cloth, Before the center belt is vulcanized, the ends of the reinforcing cloth are partially heat-sealed and temporarily fixed in a state of being superposed,
It is characterized in that the rubber adhering to the surface of the reinforcing cloth is cross-linked by heating and pressurizing to bond the entire width of the reinforcing cloth.

As described above, the reinforcing cloth is basically joined by rubber vulcanization, and even when it is temporarily fixed, only the limited part of the entire width of the belt is fused. Since there is not much difference in elongation and flexibility between the parts and the other parts, the existence of the joint does not adversely affect the running performance, noise and life of the belt.

According to a ^{second aspect of} the present invention, there is provided a method for joining a reinforcing cloth to a center belt for a high load transmission belt, wherein one fused portion has a size of 5 mm ² or less when the reinforcing cloth is temporarily fixed by heat fusion.

The portion where the canvases are heat-sealed has higher hardness and lowers flexibility and stretchability as compared with other portions, but by making the size of the fused portion smaller than a predetermined size, The effect can be minimized, and the deterioration of the belt performance can be further reduced.

According to a third aspect of the present invention, there is provided a method for joining a reinforcing belt to a center belt for a high load transmission belt, wherein fusion of the superposed reinforcing cloths is 1 to 5% of the entire width in the belt width direction.

By making the heat-bonding of the reinforcing cloth to a very small portion of 1 to 5% of the entire width of the belt, the flexibility of the reinforcing cloth is hardly reduced and the performance of the belt is completely affected. Absent.

[0023]

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 of the same. The high-load transmission belt 1 of the present invention comprises a center belt 3 composed of two core wires 5 a and 3 b having the same width, which are embedded in an elastomer 4 in a spiral shape. It is composed of a plurality of blocks 2 which are fitted into the recessed portions 6 and 7 formed at a predetermined pitch and are locked and fixed. Both side surfaces 2a, 2b of the block 2 are inclined surfaces that engage with the V groove 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 drive pulley is transmitted to the driven pulley.

As shown in FIG. 1, the block 2 is composed of an upper beam portion 8 and a lower beam portion 9 and a center pillar 10 connecting the central portions of the upper and lower beam portions 8 and 9 to each other. Grooves 11 and 12 into which the center belt 3 is fitted are formed on the surface. Also, the grooves 11, 12
Convex ridges 13 and 14 are provided on the upper and lower surfaces of the groove, so that the ridges 6 provided on the upper surface and the lower ridge 7 provided on the lower surface of the center belt 3 are engaged with each other. There is.

The upper and lower surfaces of the center belt 3 are covered with reinforcing cloths 15 and 16, respectively. The shearing force received from the block 2 when the belt is running and the friction between the block 2 and the center belt 3 are generated. The center belt is reinforced so that abrasion due to factors such as the above does not occur.

The center belt 3 as described above is manufactured, for example, by the following method. When the elastomer 4 of the center belt 3 is divided into a lower layer 4a and an upper layer 4b around the core wire 5, first, an unvulcanized rubber sheet to be the lower layer 4a is formed into a sheet having a predetermined thickness by rolling. Next, as shown in FIG. 3, the concave streak 7 is formed on one surface by the press die P.

Next, the reinforcing cloth 16 is applied to the mold having the ridges.
Is wound and temporarily fixed, and then the lower layer 4a is wound from above so that the convex ridge portion of the mold and the concave ridge portion 7 of the lower layer 4a are engaged with each other. A core wire is wound from above and an unvulcanized rubber sheet to be the upper layer 4b is further wound, a reinforcing cloth 16 is wound and temporarily fixed, and the rubber is vulcanized by heating and pressing. The method of heating and pressurizing is not particularly limited, and may be a method of covering with a jacket and placing it in a vulcanization can with steam, or a method of using a mold further provided with an electric heater from the outside.

In the present invention, as a method of temporarily fixing the reinforcing cloths 15 and 16, a method of heat-bonding the reinforcing cloths is adopted.
The heat fusion is performed under the following conditions. When the reinforcing cloth is heat-sealed, the reinforcing cloth is partially welded to the entire width in the belt width direction. Specifically, it is preferable to perform fusion bonding within the range of 1 to 5%.

When the width to be heat-sealed becomes less than 1% of the total width,
This is not preferable because the temporary fixing strength becomes insufficient and the possibility of peeling off becomes extremely high. Further, if it exceeds 5%, the degree of elongation of that portion is smaller than that of other portions and the degree of change in flexibility is large, and it is difficult to form the shape when forming the belt, and the problem that it affects belt running. Is generated, which is not preferable.

Further, the heat fusion is performed by using a heated iron, a metal rod, a needle, etc., for example, FIG.
The fused portion 17 is arranged as shown in FIG. The size of one fused portion 17 is 5 mm ² or less. Fusing part 17
The larger the size of, the greater the influence on the decrease in elongation at the joint. In the present invention, in order to reduce the influence, the size of the fused portion 17 is set to 5 mm as described above.
^{It is set to 2} or less. Fused part 17 that exceeds 5 mm ^2.
If this is the case, the decrease in elongation at the joint becomes large, which is not preferable.

Another method for manufacturing such a center belt for a high load transmission belt will be described below. FIG. 5 shows a method of molding the center belt in a state of being turned upside down. The inner mold 20 has a cylindrical shape, and a ridge portion 21 for providing a ridge portion 6 on the upper surface of the center belt is provided in the circumferential direction in the circumferential direction. It is provided at a predetermined interval.

A reinforcing cloth 15 is wound around the inner mold 20, and a rope to be the core body 5 is spun and wound in a spiral shape. An unvulcanized rubber sheet G is wound on it, and a reinforcing cloth is further wound on it (FIG. 5). In this state, by covering the outside with a jacket and heating and pressurizing the rubber sheet G, the flowability of the rubber sheet G is increased so that the inner ridge portion 2 is inserted from the gap of the core body 5.
It flows into one. The reinforcing cloth is made of woolly processed fibers such as nylon to give elasticity in the longitudinal direction of the belt.When unvulcanized rubber flows and flows into the inner mold, the canvas is not vulcanized. It is stretched by the pressure of rubber and placed on the surface of the center belt along the inner mold (Fig. 6).

By doing so, a semi-vulcanized preform having the concave streaks 6 is completed. The method of heating and pressurizing is not particularly limited, and may be a method of covering with a jacket and placing it in a vulcanization can with steam, or a method of using a mold further provided with an electric heater from the outside.

In the above steps, the reinforcing cloth is temporarily fixed when it is wound. In the present invention, the temporary fixing is carried out by heat fusion, and when the reinforcing cloth is heat fused, the entire width in the belt width direction is measured. Partial fusion, specifically, within the range of 1 to 5%.
Also, when heat-sealing, a heated iron, a metal rod,
The size of the fusion-bonded part when it is performed with a needle or the like is set to 5 mm ² or less.

Subsequently, the semi-vulcanized preform is removed from the inner mold, and the teeth of the pair of toothed pulleys are engaged with the recessed ridges to hang it, and in the span, a pair of upper and lower ridged molds are engaged. The preformed body is heated and pressed by a press die made of to vulcanize the upper concave portion 6 and the lower concave portion 7
Molding vulcanization, moving the vulcanized part in sequence, and repeating the process of molding vulcanizing the next semi-vulcanized part,
Finally, it is a method in which the entire circumference of the center belt is molded and vulcanized. The center belt having the recessed portions 6 and 7 on the upper and lower surfaces is completed.

When such a manufacturing method is adopted, the rubber stretches the reinforcing cloth and flows into the inner mold and follows the shape of the concave streak, so that the structure of the present invention is used for joining at the end of the reinforcing cloth. Therefore, it can be said that it is more useful to reduce the difference in elongation and flexibility as compared with other portions.

The other parts of the manufacturing method are not particularly limited. In the case of the above manufacturing method, only the recessed portion on the lower surface of the center belt is molded to be semi-vulcanized, and thereafter the recessed portion on the upper surface is pressed. It is vulcanized while forming the part,
With the canvas, core, rubber sheet, and canvas wrapped around the inner mold, heat and pressure are applied at once with an outer mold that has ridges that form the ridges on the upper surface of the center belt from the outside. You may manufacture the center belt which has a groove part on both surfaces. In that case, by using a split mold as the outer mold, work such as demolding can be smoothly performed.

The high load transmission belt 1 can be finally obtained by fitting the block 2 into the groove portions 6 and 7 of the center belt obtained as described above.

Polyamide resin, polyamideimide (PAI) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (P) can be used as the block resin.
Synthetic resins such as I) resin, polyether sulfone (PES) resin, and polyether ether ketone (PEEK) resin are used. Among them, they have a low friction coefficient, excellent wear resistance, rigidity and elasticity against bending. It is preferable to use a resin that has properties and is not easily broken, and a polyamide resin, particularly nylon 46 is preferable.

In the present invention, it is possible to mix a fibrous reinforcing material and a whisker-like reinforcing material in the synthetic resin forming the block as described above, and the fibrous reinforcing material is 15 to 4
It is compounded in the range of 0% by weight. If it is less than 15% by weight, there is a problem that the reinforcing effect is small and the abrasion resistance of the block is not sufficient, and if it exceeds 40% by weight, it becomes difficult to mix it with the resin and injection molding becomes difficult. There is a problem, so it is not preferable.

Examples of the fibrous reinforcing material to be mixed with the synthetic resin include aramid fiber, carbon fiber, glass fiber, polyamide fiber, polyester fiber and the like. Among them, by using nylon 46, which is a preferable example of the resin forming the block, and carbon fiber in combination, the carbon fiber can improve the water absorption defect of nylon 46 and significantly improve the rigidity, In addition, the wear resistance, impact resistance, and fatigue resistance of nylon 46 can be fully utilized.

In addition to the above organic fibers, inorganic fibers such as zinc oxide whiskers, potassium titanate whiskers and aluminum borate whiskers may be blended as the fibrous reinforcing material. Of these, zinc oxide whiskers are preferably used. Zinc oxide whiskers have a three-dimensional shape with hands extending in four directions in a tetrapot shape. This zinc oxide whisker alone has excellent heat resistance and abrasion resistance, but since it has a tetrapod-like three-dimensional shape as described above, when it is blended with carbon fiber, the orientation of carbon fiber Is suppressed, and the anisotropy of warpage and molding shrinkage during molding 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 stable, so that the wear resistance is improved. To do.

Further, since the zinc oxide whiskers have a high specific gravity and a high rigidity, it is possible to reduce vibration at the time of contact with the pulley and to reduce noise generation. When the amount of this zinc oxide whisker is small, the effect of addition is not exhibited, and when it is too large, kneading cannot be performed and molding becomes difficult.

By adopting such a material constitution,
It has strength such as rigidity and toughness that can withstand the lateral pressure that it receives when it comes into contact with the pulley, and it has excellent wear resistance.
Furthermore, it becomes possible to form a block that is strong against heat generated during friction, and the power received from the pulleys can be efficiently transmitted to the center belts 3a and 3b as a tensile force, and a tension transmission type high load transmission belt. Can be configured.

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

What is used as the rubber 4 of the center belts 3a, 3b is a single material such as chloroprene rubber, natural rubber, nitrile rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, or a rubber or polyurethane in which these are appropriately blended. Examples thereof include rubber. As the core body 5, a rope selected from polyester fiber, polyamide fiber, aramid fiber, glass fiber, steel wire and the like is used.

As the reinforcing cloth, a plain weave, a twill weave, or a satin weave canvas made of polyester fiber, polyamide fiber, acrylic fiber, vinylon fiber, polyethylene fiber, polypropylene fiber, polyvinyl fiber, polyurethane fiber, etc. can be used, and the uneven shape can be used. When elasticity is particularly required for forming, a fiber having elasticity such as wooly nylon is used as a fiber corresponding to the longitudinal direction of the belt.

Further, rubber is attached to the surface of the reinforcing cloth, and examples of the attachment method include coating with a thin unvulcanized rubber sheet, friction, and a method of applying rubber glue. .

[0049]

As described above, according to the first aspect of the present invention, a high load transmission including a center belt having a core body embedded in rubber and a plurality of blocks fitted and fixed along the longitudinal direction of the center belt. A center belt used for a belt, wherein a reinforcing cloth is bonded to the surface of a reinforcing cloth in a method of joining a reinforcing cloth to a center belt in which at least one of upper and lower surfaces is covered with the reinforcing cloth, Prior to vulcanization of the center belt, the edges are partially heat-sealed and temporarily fixed in a stacked state, and then heated and pressed to crosslink the rubber adhering to the surface of the reinforcing cloth to reduce the overall width of the reinforcing cloth. Characterized by joining.

As described above, the reinforcing cloth is basically joined by vulcanization of rubber, and even when temporarily fixed, only a limited part of the entire width of the belt is fused. Since there is not much difference in elongation and flexibility between the parts and the other parts, the existence of the joint does not adversely affect the running performance, noise and life of the belt.

According to the second aspect of the present invention, when the reinforcing cloth is temporarily fixed by heat-sealing, the size of one fused portion is 5 mm ² or less, and the reinforcing belt joining method for the center belt for the high load transmission belt is used.

The portion where the canvases are heat-sealed has higher hardness and lowers flexibility and stretchability as compared with the other portions. However, by making the size of the fused portion smaller than a predetermined size, The effect can be minimized, and the deterioration of the belt performance can be further reduced.

According to a third aspect of the present invention, the reinforcing cloth joining method for the center belt for a high load transmission belt is such that the fusion of the superposed reinforcing cloths is 1 to 5% of the entire width in the belt width direction.

By heat-bonding the reinforcing cloth to a very small portion of 1% to 5% of the total width of the belt, the flexibility of the reinforcing cloth is hardly reduced and the performance of the belt is completely affected. Absent.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an example of a high load transmission belt according to the present invention.

FIG. 2 is a side sectional view of a high load transmission belt.

FIG. 3 is a cross-sectional view of an unvulcanized rubber sheet that has been press-molded.

FIG. 4 is a perspective view of the reinforcing cloths superposed and fused.

FIG. 5 is a cross-sectional view of a core body and an unvulcanized rubber sheet wound around an inner mold.

FIG. 6 is a cross-sectional view of an unvulcanized rubber sheet which is made to flow and poured into an inner mold.

[Explanation of symbols]

1 High load transmission belt 2 blocks 3a Center belt 3b center belt 4 Elastomer 4a inner layer 4b outer layer 5 cores 6 concave section 7 concave section 8 Upper beam part 9 Lower beam part 10 center pillars 11 grooves 12 grooves 13 ridge 14 ridge 15 Reinforcement cloth 16 Reinforcing cloth 17 Fusion part 20 Internal type 21 ridge

Claims (3)

[Claims] 1. A center belt for use in a high load transmission belt comprising a center belt having a core body embedded in rubber and a plurality of blocks fitted and fixed along the longitudinal direction of the center belt, wherein at least one of the upper and lower belts is used. In a method for joining a reinforcing cloth to a center belt whose one side is covered with a reinforcing cloth, a reinforcing cloth having rubber attached to its surface is used, and the ends of the reinforcing cloth are joined together before the center belt is vulcanized. Partially heat-sealed and temporarily fixed in the overlapped state,
A method for joining a reinforcing belt to a center belt for a high load transmission belt, characterized by cross-linking the rubber adhering to the surface of the reinforcing cloth by heating and pressurizing and then joining the entire width of the reinforcing cloth. 2. The method for joining a reinforcing cloth to a center belt for a high load transmission belt according to claim 1, wherein when the reinforcing cloth is temporarily fixed by heat fusion, the size of one fused portion is 5 mm ² or less. 3. A method for joining a reinforcing cloth to a center belt for a high load transmission belt according to claim 1, wherein the fusion of the superposed reinforcing cloths is 1 to 5% of the total width in the belt width direction.