JP4528090B2 - Transmission belt canvas, transmission belt using the same, and method for manufacturing transmission belt canvas - Google Patents

Description

  The present invention relates to a transmission belt canvas, a transmission belt using the same, and a method for manufacturing the transmission belt canvas.

  A transmission belt such as a V-ribbed belt used for driving an auxiliary machine for an automobile generally uses a woven or knitted fiber as a back material. The size (peripheral length) of such a belt is arbitrary, and therefore the length of the canvas needs to be adjusted appropriately. So far, cotton or cotton-polyester blended canvas commonly used for power transmission belts is either jointed by wrapping the ends of two canvas-cut canvases, or by joining two canvases together. The end surfaces were brought into a butted state and sewed with a sewing thread to form a joint. However, the former has a problem that abnormal noise and vibration are generated on the rear pulley due to a step formed between the portion where the canvas wrap portion is not wrapped. In the latter case, since the sewing thread is worn and cut when the joined portion of the running canvas is repeatedly contacted with the rear pulley, the canvas becomes unjoined after a certain run, which causes the problem of peeling of the canvas. was there.

In consideration of these points, a canvas subjected to resorcin-formalin-latex treatment is overlapped as a transmission belt canvas to be attached to the back of the belt, and the vicinity thereof is bonded by thermocompression bonding by ultrasonic vibration. A method has been proposed in which a cylindrical canvas having a predetermined circumference is obtained by melting and cutting (see Patent Document 1).
JP 2003-97648 A

  However, in the above method using a canvas that has only been subjected to a resorcin-formalin-latex treatment, there is a problem that the joint strength at the seam of the canvas is very low because the fibers of the canvas are not welded together.

  In this regard, in order to ensure joint strength, it is considered to perform welding using a canvas formed of 100% synthetic fiber, such as a nylon canvas. However, since the seam is completely welded by this method, the elongation effect inherent in the woolly nylon thread is almost diminished, and the probability of cracks occurring at the seam seam after a constant running of the transmission belt is high. There is a problem of becoming.

  The present invention has been made in view of the above points, and the object of the present invention relates to a joining portion of a canvas for a transmission belt, without causing abnormal noise or vibration on a rear pulley, and after a certain amount of traveling. Another object of the present invention is to provide a canvas having a structure in which joint strength is high at the joint portion of the canvas and cracks are hardly generated at the joint portion without causing separation of the canvas. It is another object of the present invention to provide a transmission belt using such a canvas as a back canvas. Furthermore, it is providing the manufacturing method of the canvas for power transmission belts as mentioned above.

  Therefore, in order to achieve the above object, the present inventor made the following invention using a canvas formed by blended yarns of cotton fibers and thermoplastic synthetic fibers.

That is, the invention according to claim 1
A transmission belt canvas formed by blended yarns of cotton fibers and thermoplastic synthetic fibers,
Several canvases are spliced together to be long,
In the joint portion, the two adjacent canvases are the canvases for a transmission belt, in which the thermoplastic synthetic fibers are welded to each other and the cotton fibers are engaged with each other while maintaining the shape of the yarn.

  In the case of the above invention, since a canvas formed by blended yarns of cotton fibers and thermoplastic synthetic fibers is used, the thermoplastic synthetic fibers are welded to each other at the seam portion of the two canvases, while the cotton fibers are While maintaining the shape of the yarn, it is possible to create a transmission belt canvas having a structure in which it enters the welded portion of the thermoplastic synthetic fiber and engages with the cotton fiber of the counterpart canvas. According to such a structure, since the fibers themselves are jointed by the welding of the thermoplastic synthetic fibers, the advantage is that the joint strength is increased at the joint portion of the canvas, and the cotton fibers of the welded portions of the thermoplastic synthetic fibers are also threaded. Since the shape is maintained, it is possible to have the advantage of maintaining a corresponding elongation effect in the canvas joint portion.

The invention according to claim 2
In the canvas for power transmission belts according to claim 1,
A canvas for power transmission belts characterized in that a thermoplastic synthetic fiber is 20% or more and 85% or less with respect to a blend ratio of cotton fiber and thermoplastic synthetic fiber.

  By using the canvas for a transmission belt having the above-described configuration, it is possible to create a state in which the utility is maximized with respect to the correlation between the joint strength and the elongation effect at the joint portion of the canvas.

The invention according to claim 3 is:
The transmission belt canvas according to claim 1 or 2 is a transmission belt used as a back canvas.

  According to the transmission belt having the above-described configuration, a transmission belt can be provided in which the canvas has a high joint strength at the canvas joint portion and the canvas that maintains the stretch effect at the joint portion is used as the back canvas. The crack resistance at the joint portion is increased, so that the durability running time of the transmission belt can be extended.

The invention according to claim 4 is:
A method for producing a canvas for a transmission belt, comprising:
Cutting a canvas formed by blended yarns of cotton fibers and thermoplastic synthetic fibers into a bias shape to create a plurality of bias cut canvases;
A step of superimposing the two bias-cut canvases so that the respective non-cut side ends are aligned and the canvas front surfaces or the back surfaces are in contact with each other;
Welding each other's thermoplastic synthetic fibers along the aligned non-cut side ends,
Opening the bias-cut canvas that has been superposed to form a combined canvas;
A step of cutting and removing the surplus portion in the welded portion,
A method of manufacturing a canvas for a transmission belt, wherein a plurality of the bias-cut canvases are connected to obtain a long canvas by repeating the above steps.

  According to the above method, a canvas for a transmission belt having the same structure as that of the invention of claim 1 can be created. Therefore, when the thermoplastic synthetic fiber is welded, the fiber itself is jointed, and the joint strength at the seam is increased. It is possible to have both the advantage that the cotton fiber maintains the shape of the yarn even in the welded portion of the thermoplastic synthetic fiber, and the advantage that a corresponding elongation effect can be maintained in the canvas joint portion.

  In addition, when forming a transmission belt in which the shape of the transmission belt is a cylindrical shape having a predetermined circumference, the joint portions necessary for forming the cylindrical canvas are the same as those described above. In addition, the thermoplastic synthetic fibers of the two adjacent canvases are welded to each other, and the mutual cotton fibers are formed to be engaged with each other while maintaining the shape of the yarn in the welded portion, that is, The effect of combining the advantage that the joint strength at the joint portion is increased and the advantage that a corresponding elongation effect can be maintained at the joint portion can be obtained.

  The following three points can be given as the effects of the transmission belt canvas according to the present invention, the transmission belt using the same, and the method for producing the transmission belt canvas.

  First, the ends of the two canvases to be joined are not wrapped and jointed by lap joints, but the joints are created by creating a state equivalent to the end face of each canvas being joined, so the canvas wrap part There is no problem that abnormal noise or vibration is generated on the rear pulley due to the step formed between the unwrapped parts.

  Secondly, the end faces of the two canvases are not butted together and sewn with the sewing thread, and the joints are made without using the sewing thread by welding the thermoplastic synthetic fibers of the canvas together. There is no problem that the canvas peels off after a certain amount of wear and cutting.

  Thirdly, as described above, the canvas itself is formed by blended yarns of cotton fibers and thermoplastic synthetic fibers, and the fibers themselves are jointed by the thermoplastic synthetic fibers being welded. Therefore, the resorcin-formalin-latex treatment is performed. The joint strength at the seam seam is higher than when using just-treated cotton canvas, and at the same time, the cotton fiber enters the welded part of the thermoplastic synthetic fiber while maintaining the shape of the thread. Because the cotton fibers are bonded to each other through the thermoplastic synthetic fibers welded by the above, and the corresponding stretch effect can be maintained at the seam seam, it is welded using a canvas made of 100% synthetic fibers such as nylon canvas Compared with the case where it does, it is hard to produce a crack in a canvas joint part.

  In particular, in the case of the configuration of the invention according to claim 2, it is possible to create a state in which the utility is maximized with respect to the correlation between the joint strength and the elongation effect at the joint portion of the canvas. The crack resistance at the mating portion can also be improved to the maximum.

  Further, according to the invention of claim 3, it is possible to provide a transmission belt having a long durability running time due to the increased crack resistance at the joint portion of the transmission belt canvas.

  Embodiments of a transmission belt canvas according to the present invention, a transmission belt using the same, and a method for manufacturing the transmission belt canvas will be specifically described below with reference to the drawings.

<Structure>
First, the structure of the transmission belt canvas according to the present invention and the transmission belt used therewith will be described with reference to the V-ribbed belt 1 shown in FIG.

  Reference numeral 1 denotes a V-ribbed belt body. The V-ribbed belt 1 includes an adhesive rubber layer 3 in which a core wire 2 extending in the belt longitudinal direction is embedded, and a plurality of rib portions extending in parallel to each other in the belt longitudinal direction on the bottom surface of the belt body. , And a back canvas 5 formed of cotton-polyester blend yarn 7 that covers the back of the belt body integrally.

  Here, the back canvas 5 is subjected to a resorcin-formalin-latex treatment, and the two back canvases 5 and 5 are joined by welding the resorcin-formalin-latex and the polyester at the canvas joining portion 6. Yes.

  In addition, FIG. 2 shows that when the spliced portion 6 is viewed microscopically, the cotton fibers 7a and 7a of the cotton-polyester blended yarns 7 and 7 that weave the two back canvases 5 and 5 to be joined together. It is explanatory drawing which shows notionally the state which is mutually engaged in the canvas splicing part 6. FIG. In this figure, the polyester fiber is not explicitly drawn, but the polyester fiber is thermally welded in the range of the joint portion 6 of the rear canvases 5 and 5 (reference numeral 8). The cotton fibers 7a, 7a,... Are buried in the polyester welded tightly without gaps at the seam 6 while maintaining the shape of the yarns, and therefore the respective cotton fibers 7a, 7a,. The two are bonded to each other via the welded polyester (while partly in contact).

<Manufacturing method>
Next, the manufacturing method of the transmission belt canvas according to the present invention will be described with reference to FIG.

  First, a plain weave canvas 5a in which the cotton-polyester blend yarn 7 is woven so that the warp and weft have an intersecting angle of 90 ° and the surface is integrated with a resorcin-formalin-latex treatment is prepared. A plurality of bias-cut canvases 5b, 5b,... Are created by using a bias cutter (not shown) so that the warp yarn is cut at 45 ° with respect to the canvas width direction.

  The two bias-cut canvases 5b and 5b thus obtained are overlapped so that one of the respective non-cut side ends is aligned with each other and the canvas surfaces are in contact with each other. A high frequency vibration is applied in a straight line with a constant width along the part, and the resorcin-formalin-latex and polyester fiber of the bias-cut canvases 5b and 5b are heat-welded. Next, the bias cut canvases 5b and 5b that have been superposed are opened to form a single bonded canvas, and the surplus portion 5c in the welded portion is cut and removed to finish the canvas joining portion 6a flat. Thereafter, the procedure for combining the bias-cut canvases 5b and 5b is repeated to obtain one long bias canvas 5d. Note that the remaining portion 5c in the welded portion may be cut and removed before opening the bias cut canvas 5b, 5b that has been overlapped.

  Next, two long bias canvases 5d and 5d obtained by the above method are aligned vertically and overlapped, and cut by a fixed size using an unillustrated automatic feeder to obtain a cylindrical canvas 12 for a V-ribbed belt. .

  This process will be described in detail with reference to FIG. That is, high-frequency vibration is applied vertically in the canvas width direction using a horn portion 9 and a receiving jig 10 at a predetermined portion of two long bias canvases 5d and 5d that are vertically aligned and overlapped. While the resorcinol-formalin-latex and polyester fiber of the shank bias canvas 5d and 5d are heat-welded to each other, at the same time, substantially the center of the welded portion is cut in the width direction of the canvas to obtain the melt-cut portion 11. Here, the melt-cut portion 11 is formed by cutting the two long bias canvases 5d and 5d superposed on each other at this portion in the width direction while jointing them. This means that when the two long bias canvases 5d, 5d that have been overlapped are opened for each of the paired long canvases, the end surfaces of the cut canvases are exactly the same at the melt cutting section 11. This means that the same state as that of welding is formed, and thus the melt cut portion 11 forms the joint portion 6b shown in FIG. The melt-cut portion 11 is formed at two locations at predetermined intervals in the longitudinal direction of two long-biased canvases 5d and 5d, which are vertically aligned and overlapped, so that a cylindrical V-ribbed belt canvas is formed. 12 can be obtained. As in the case of creating a long bias canvas, when it is necessary to finish the joining portion 6b flat, the remaining portion of the welded portion is cut and removed.

<Crack durability test>
First, FIG. 5 is an explanatory diagram showing how the crack durability test was performed on the transmission belt canvas according to the present invention. That is, the cylindrical V-ribbed belt 1 to which the rear canvas 5 is attached is passed over the drive pulley 13 and the driven pulleys 14 and 14 and is run with a tension of 75 kgf applied to the rear pulleys 15 and 15. Indicates the state.

  In this crack durability test, when the V-ribbed belt 1 is run in this state, the joint portion 6 of the back canvas is cracked (more specifically, the crack generated in the joint portion 6 is formed in the two core wires. It is seen how the travel time until it reaches (up to) varies depending on the type of material of the back canvas. The results are shown in FIG. 6, FIG. 7, and FIG.

  First, FIG. 6 shows three points of joint strength and elongation rate (measurement of elongation at break when measuring strength in the warp warp direction) at the joint portion of the back canvas of each material, and travel time until cracks occur in the joint portion. Is expressed numerically.

  The warp and weft constituting each canvas were both twisted at 295 dtex, the number of driven pieces in a width of 5 cm was 80, and the thickness of the canvas was 0.7 mm. In addition, a resorcin-formalin-latex treatment having a mass ratio of 13% to 15% with respect to the original fabric is performed, and the seam is welded by vibration at a frequency of 20 kHz. The sample length of each canvas was 250 mm, and the tensile speed in the joint strength measurement was 500 mm / min. The canvas formed of cotton-polyester blended yarn is not subjected to bias processing to match the test conditions, and the strength is measured in the warp direction in a state where the warp is spliced so that the warp is 90 ° with respect to the width of the canvas. On the other hand, 2/2 twill weave canvas using weft nylon yarn was spliced in parallel with the weft yarn, and the strength was measured in the warp direction.

  From FIG. 6, it can be said that both the joint strength and the elongation ratio are the best when the canvas using only cotton is joined with a sewing machine. Therefore, there is a problem that the sewing thread is worn and cut on the rear pulley as the belt travels, resulting in low crack durability. Therefore, it can be seen that the running time until cracking is less than half the value of the case of the back canvas made of a material having a cotton / polyester ratio of 40% / 60%. It can be concluded that the back canvas of the material having a cotton / polyester ratio of 60% / 40% to 40% / 60% is the best from the running time until cracking occurs. Conversely, it can be read that when the content ratio of cotton or polyester is biased to either direction, sufficient crack durability is not exhibited.

  FIG. 7 is a graph showing the joint strength and elongation rate of the back canvas of each material in FIG. 6 for reference. Here, the running time until cracking is not shown.

  FIG. 8 is a graph showing the running time until cracking of each material in FIG. 6, and in particular for the canvas formed of cotton-polyester blended yarn, which crack-resistant running time depends on the change in the cotton / polyester ratio. It clearly shows how it changes. Also from FIG. 8, as described above, when the cotton / polyester ratio is 60% / 40% to 40% / 60%, it can be said that the travel time until the crack is generated in the canvas joint portion is the longest. .

  From the above test, it can be said that when the cotton / polyester ratio is about 50% / 50%, the crack life of the running canvas is the best. This is thought to be due to the following circumstances.

  That is, as the cotton content ratio increases, the polyester content ratio decreases, and accordingly, the volume of the welded portion in the canvas joint portion decreases, resulting in a weak joint strength, leading to premature breakage. Conversely, when the polyester content ratio increases, the joint strength of the canvas increases because the volume of the welded portion increases, but on the other hand, the cotton content ratio decreases, so the elongation rate at the seam seam decreases and breaks easily. It will be damaged early.

  The most suitable cotton / polyester ratio is about 50% / 50% in terms of both joint strength and elongation.

<Effect>
Originally, the back canvas material used for the V-ribbed belt is biased to give flexibility in the circumferential direction, and each yarn has a specified angle with respect to the circumferential direction. Therefore, although it has the flexibility to the circumferential direction by bias processing, since the polyester component is welded to the joint part, it hardly has elongation. Therefore, synthetic fibers such as nylon and polyester cause premature breakage of the canvas joint during traveling.

  The cotton canvas has a very weak joint strength because the fibers themselves are not welded, and the joint portion of the canvas is damaged from the beginning of running. Further, in the joining by the sewing machine, the joint strength is high, but the sewing thread is worn and cut as the belt travels, and a crack is generated in the joining part.

  Compared with the canvas of the above materials, the cotton-polyester blended canvas has a polyester component welded during high-frequency vibration and is physically jointed via a synthetic fiber. Here, since the synthetic fiber melts at the time of welding, the fiber loses its shape and maintains little elongation, but the cotton fiber is buried while maintaining the shape of the yarn in the welded portion of the polyester component. The elongation of the yarn itself is maintained (see FIG. 2). Therefore, when the cotton / polyester ratio is about 50% / 50%, the canvas has the necessary joint strength and elongation, and the crack resistance at the joint portion of the canvas is most improved.

  In the above embodiment, the transmission belt is a V-ribbed belt. However, the present invention can be applied to any transmission belt to which a canvas is attached.

  Moreover, although the canvas formed by the cotton-polyester blended yarn was shown as the material of the canvas, the type is not limited as long as it is formed by the blended yarn of cotton fiber and thermoplastic synthetic fiber.

  Further, in the case of a canvas formed by cotton-polyester blended yarn, it is preferable that the high frequency to be vibrated to weld the polyester when forming the canvas joint portion is 10 kHz to 30 kHz, but the selected thermoplastic synthetic fiber It is assumed that a high frequency with an appropriate frequency is selected according to the type.

The perspective view which shows the structure of the transmission belt formed using the canvas for transmission belts concerning this invention. Explanatory drawing which shows the state in which the cotton fiber of the cotton-polyester mixed yarn which wovens the adjacent canvas is mutually engaged in the joint part of the canvas for transmission belts concerning this invention. Explanatory drawing which shows the manufacturing method of the canvas for power transmission belts concerning this invention. Explanatory drawing which shows the method of obtaining the canvas for cylindrical V-ribbed belts. Explanatory drawing which shows how the crack durability test regarding the canvas for power transmission belts concerning this invention was done. The figure which represented the result of the crack endurance test about the canvas for power transmission belts concerning the present invention numerically. The graph which shows the result of the crack endurance test regarding the canvas for power transmission belts concerning this invention. The graph which shows the result of the crack endurance test regarding the canvas for power transmission belts concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 V ribbed belt 2 Core wire 3 Adhesive rubber layer 4 Rib part 5 Back canvas 5a Plain weave canvas 5b Bias cut canvas 5c Extra part 5d Long bias canvas 6 Canvas joining part 6a Two bias cut canvases 5b and 5b were joined Joint part 6b Joint part 7 to obtain a cylindrical canvas from a long biased canvas 7 Cotton-polyester blended yarn 7a Cotton fiber 8 Polyester fiber welded part 9 Horn part 10 Receiving jig 11 Melting cut part 12 Cylindrical shape V-ribbed belt canvas 13 Driving pulley 14 Driven pulley 15 Rear pulley

Claims (5)

A transmission belt canvas formed by blended yarns of cotton fibers and thermoplastic synthetic fibers,
Several canvases are spliced together to be long,
A canvas for a transmission belt, wherein two adjacent thermoplastic synthetic fibers are welded to each other at the seam, and the cotton fibers are partially in contact with each other while maintaining the shape of the yarn. In the canvas for power transmission belts according to claim 1,
A canvas for a transmission belt, characterized in that a thermoplastic synthetic fiber is 20% or more and 85% or less with respect to a blend ratio of cotton fiber and thermoplastic synthetic fiber.   A transmission belt in which the canvas for a transmission belt according to claim 1 or 2 is used as a back canvas. A method for producing a canvas for a transmission belt, comprising:
Cutting a canvas formed by blended yarns of cotton fibers and thermoplastic synthetic fibers into a bias shape to create a plurality of bias cut canvases;
A step of superimposing the two bias-cut canvases so that the respective non-cut side ends are aligned and the canvas front surfaces or the back surfaces are in contact with each other;
Welding each other's thermoplastic synthetic fibers along the aligned non-cut side ends,
Opening the bias-cut canvas that has been superposed to form a combined canvas;
A step of cutting and removing the surplus portion in the welded portion,
A method for manufacturing a canvas for a transmission belt, wherein a plurality of bias cut canvases are connected to obtain a long canvas by repeating the above steps. In the canvas for power transmission belts according to claim 1 or 2,
In the splicing portion, the two adjacent canvases are embedded in a synthetic fiber to which the respective cotton fibers are welded.

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