JP2018009588A - V-ribbed belt and manufacturing method of v-ribbed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a V-ribbed belt which can be manufactured by a molded manufacturing process, in which an aramid core wire is provided as nearer as possible to a rib bottom, and a back face rubber with an appointed thickness is formed between the aramid core wire and a belt back face.SOLUTION: A V-ribbed belt comprises a back face rubber, a middle canvas, an adhesion rubber, an aramid core wire, a main body rubber and a face side canvas. Multiple V-shape rib extending to the belt longer direction is formed to the main body rubber. The middle canvas is provided to the belt back face side than the aramid core wire, consists of fabric cloth consisting of warp extending to the belt longer direction and weft extending to the belt width direction, and has more than 20/cm placing density of the weft.SELECTED DRAWING: None

Description

  The present invention relates to a V-ribbed belt used for driving an auxiliary machine of an automobile engine, for example.

  Conventionally, this type of V-ribbed belt is known in which the rib surface is covered with a canvas to reinforce the rib surface and reduce running noise. Such a V-ribbed belt is manufactured by a so-called molding method in order to provide canvas on the surface of the rib. On the other hand, in recent years, the load of driving an auxiliary machine of an automobile engine has increased, and therefore, an aramid fiber having a high elastic modulus is increasingly used as a tension cord for a V-ribbed belt. In order to increase the durability of the V-ribbed belt, it is known that the tension cord is provided in the belt body, and it is desirable to minimize the distance from the center line of the tension cord to the rib apex and the rib / pulley interface. (Patent Document 1).

JP 2005-516790 Gazette

  In order to manufacture a V-ribbed belt having a rib surface covered with a canvas and provided with a tension cord (aramid core) made of an aramid fiber, a molding method must be employed. However, since the aramid core wire is difficult to stretch, the unvulcanized rubber of the unvulcanized back rubber sheet set on the back side of the belt from the aramid core wire at the time of belt molding is plasticized by heating. The aramid cords are pressed from the back side of the belt by the mold bag, flow at the rib side of the belt through the gap between the aramid cords extending in the belt longitudinal direction and aligned at a certain interval in the belt width direction. A problem arises in that the durability of the V-ribbed belt becomes insufficient because it is set at a position relatively far from the rib bottom of the V-ribbed belt, that is, a position near the back surface of the belt.

  The present invention can be manufactured by a molding method, and an aramid cord is provided as close to a rib bottom as possible in a V-ribbed belt, and a back rubber having a predetermined thickness is formed between the aramid cord and the back of the belt. The object is to provide a V-ribbed belt.

  The V-ribbed belt according to the present invention is a V-ribbed belt comprising a back rubber, an intermediate canvas, an adhesive rubber, an aramid core wire, a main rubber, and a surface canvas, and a plurality of V-shaped ribs extending in the longitudinal direction of the belt are formed on the main rubber. The intermediate canvas provided on the back side of the belt with respect to the aramid cord is composed of a woven fabric composed of warp yarns extending in the belt longitudinal direction and weft yarns extending in the belt width direction, and the weft density of the intermediate canvas is 20 / It is characterized by being cm or more.

  The weft density of the intermediate canvas is more preferably 24 yarns / cm or more. Further, the elongation ratio of the intermediate canvas in the extending direction of the weft is, for example, 100% / 2 Kgf · 2.5 cm or more, and more preferably 125% / 2 Kgf · 2.5 cm or more.

  The thickness of the back member made of the back rubber, intermediate canvas, and adhesive rubber of the V-ribbed belt is, for example, 1.30 mm or more, and more preferably 1.55 mm or more.

  The height from the center position of the aramid cord of the V-ribbed belt to the surface of the back rubber is, for example, 1.0 mm or more.

  The manufacturing method of the V-ribbed belt according to the present invention includes an unvulcanized back rubber sheet that respectively constitutes the back rubber, intermediate canvas, adhesive rubber, aramid cord, main body rubber, and surface canvas after molding from the inner periphery side, An intermediate canvas jacket, an unvulcanized adhesive rubber sheet, an aramid core, an unvulcanized main body rubber sheet, and a surface canvas jacket are laminated in this order, and the surface canvas jacket is placed on the inner peripheral wall of the outer mold. This is a method for manufacturing a V-ribbed belt in which a plurality of V-shaped ribs extending in the longitudinal direction of the belt are formed on the main rubber by heating the cylindrical slab intermediate body while pressing the cylindrical slab intermediate from the inner peripheral side. The intermediate canvas is provided on the back side of the belt with respect to the aramid cord, and is made of a woven fabric comprising warps extending in the circumferential direction of the cylindrical slab intermediate and wefts extending in the axial direction of the cylindrical slab intermediate. Made which are characterized in that implantation density of the intermediate canvas weft is a manufacturing method of the V-ribbed belt is characterized in that 20 present / cm or more.

  According to the present invention, it can be manufactured by a molding method, the aramid cord is provided as close as possible to the bottom of the rib of the V-ribbed belt, and a back rubber having a predetermined thickness is formed between the aramid cord and the back of the belt. V-ribbed belt is obtained.

It is a perspective view which shows the V-ribbed belt which is one Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the V ribbed belt by a molding method. It is sectional drawing which shows the structure of the V-ribbed belt of a comparative example and an Example. It is a figure which shows the structure of the apparatus for implementing a 1st durability test. It is a figure which shows the structure of the apparatus for implementing a 2nd durability test.

  The present invention will be described below based on the illustrated embodiments. In FIG. 1, a rib 11 having a V-shaped cross section and extending in the longitudinal direction is formed on the surface side (lower side of the figure) of the main rubber 21 of the V-ribbed belt 10. Is covered. A flat back rubber 13 is provided on the back side of the V-ribbed belt 10. Between the rib 11 and the back rubber 13, an aramid core wire 15 as a tension cord and an intermediate canvas 14 are embedded. The aramid core wire 15 extends in the longitudinal direction of the V-ribbed belt 10 and is provided at a predetermined interval in the cross section. In the cross section, between the adjacent aramid core wires 15, an adhesive rubber 16 for bonding the intermediate canvas 14 to the core wires 15 and the ribs 11 is filled, and a part of the adhesive rubber 16 bulges toward the rib 11 side. Yes. The back rubber 13, the intermediate canvas 14 and the adhesive rubber 16 constitute a back member 17 of the V-ribbed belt.

The V-ribbed belt 10 is formed by a molding method.
With reference to FIG. 2, the manufacturing method of the V ribbed belt by a molding method is demonstrated. This manufacturing apparatus includes a cylindrical outer mold 31, an inner mold 32 disposed concentrically inside the outer mold 31, and a mold bag 33 provided so as to cover the inner mold 32. Have. The cylindrical slab intermediate 20 ′, which is in a state before being molded into the V-ribbed belt 10, is disposed concentrically with these molds 31 and 32 in the space between the outer mold 31 and the inner mold 32. The That is, the outer peripheral surface of the cylindrical slab intermediate 20 ′ faces the outer mold 31, and the inner peripheral surface of the cylindrical slab intermediate 20 ′ faces the mold bag 33.

  The cylindrical slab intermediate 20 ′ is formed from an inner peripheral side, after molding, a back rubber 13, an intermediate canvas 14, an adhesive rubber 16, an aramid core wire 15, a main body rubber 21, and a surface canvas 12, which are unvulcanized. The back rubber sheet 13 ', the intermediate canvas jacket 14', the unvulcanized adhesive rubber sheet 16 ', the aramid core wire 15, the unvulcanized main body rubber sheet 21', and the surface canvas jacket 12 'are laminated in this order. The surface canvas jacket 12 ′ is disposed so as to face the inner peripheral wall surface of the mold 31. The mold bag 33 is expanded by supplying high-pressure high-temperature water therein, and presses the cylindrical slab intermediate 20 ′ against the inner peripheral wall of the outer mold 31. At this time, the inside of the outer mold 31 is heated to a high temperature. As a result, the cylindrical slab intermediate 20 'is vulcanized while being pressed from the inner peripheral side, and a cylindrical slab in which a plurality of V-shaped ribs 11 extending in the circumferential direction are formed on the outer peripheral surface of the main rubber 21 is manufactured. Is done.

  In this embodiment, the intermediate canvas 14 is a woven fabric composed of warp yarns extending in the longitudinal direction of the V-ribbed belt (circumferential direction of the cylindrical slab) and weft yarns extending in the width direction of the V-ribbed belt (axial direction of the cylindrical slab). Yes, it may be plain woven or twill woven. The thickness of the intermediate canvas 14 is 0.75 mm, for example. For example, both the warp and the weft are nylon 66, but only one of the weft and the warp may be nylon 66. The warp driving density is 30 yarns / cm or more, more preferably 40 yarns / cm or more. The driving density of the weft is 20 pieces / cm or more, more preferably 24 pieces / cm or more. Further, the elongation ratio of the intermediate canvas in the extending direction of the weft is 100% / 2 Kgf · 2.5 cm or more, and more preferably 125% / 2 Kgf · 2.5 cm or more. The elongation ratio of the intermediate canvas in the present application refers to the elongation ratio of the canvas when a load of 2 kgf is applied to a 2.5 cm width strip-shaped canvas.

  The back rubber 13 is, for example, EPDM rubber or EPM rubber. The adhesive rubber 16 is, for example, EPDM rubber or CR rubber. The thickness of the back member composed of the back rubber 13, the intermediate canvas 14, and the adhesive rubber 16 is, for example, 1.30 mm or more, and more preferably 1.55 mm or more.

  In the V-ribbed belt 10 formed using the cylindrical slab intermediate 20 ′ having the above-described configuration, the height from the center position of the aramid core wire 15 to the surface of the back rubber 13 is, for example, 1.0 mm or more. Preferably it is 1.30 mm or more.

Next, referring to Table 1, the results of trial manufacture of the V-ribbed belt will be described.
In Comparative Examples 1 and 2 and the example, the basic configuration of the back member is common, but the intermediate canvases are different from each other, and the details are as shown in Table 1. The back rubber is made of EPDM rubber, and the adhesive rubber is made of EPDM rubber. The thicknesses of the back members are different from each other and are as shown in Table 1.

  As shown in Table 1, the basic difference in configuration between Comparative Examples 1 and 2 and Examples is in the intermediate canvas, and the wefts are particularly different. That is, the driving density of the weft is 1.6 / cm in Comparative Example 1, 8 / cm in Comparative Example 2, and 24 / cm in the Example. Further, when the load of 2 Kgf / 2.5 cm width is applied, the elongation ratio in the extending direction of the weft of the intermediate canvas is usually 20 to 30% (Comparative Examples 1 and 2), whereas in the example, it is 125. % Or more.

  As shown in FIG. 3A, the V-ribbed belt 40 having the back member structure of Comparative Example 1 passes through the intermediate canvas 44 and enters between the aramid core wires 45 during molding, and the adhesive rubber 46 is on the back. It is pushed by the rubber 43 and protrudes to the rib 41 side. The V-ribbed belt 50 of the comparative example 2 uses the intermediate canvas 54 having a higher weft threading density than that of the comparative example 1. However, as shown in FIG. 3B, the V-ribbed belt 40 of the comparative example 1 is used. Similarly, the back rubber 53 passes through the intermediate canvas 54 and enters between the aramid core wires 55.

  In contrast, in the V-ribbed belt 10 having the back member configuration of the embodiment, as shown in FIG. 3C, the back rubber 13 is located on the belt back side with respect to the intermediate canvas 14. The adhesive rubber 16 is filled in between, and the intermediate canvas 14 is bonded to the aramid core wire 15 and the rib 11 by the adhesive rubber 16.

  In the comparative examples 1 and 2 and the V-ribbed belts 40, 50, and 10 of the examples, the aramid core wires 45, 55, and 15 are aligned at substantially equal intervals, respectively. It is in contact with the canvas 44 and 54 and cannot be used as a product. The heights H from the belt back surface to the center lines of the aramid core wires 45, 55 and 15 are 0.62 mm, 0.75 mm and 1.30 mm, respectively. Further, in the positional relationship between the aramid core wire and the rib bottom portion, the aramid core wire of the V-ribbed belt 10 of the embodiment is disposed at a position closest to the rib bottom portion 11a, and the aramid core wire of the V-ribbed belt 40 of Comparative Example 1 is the rib bottom portion 41a. The positional relationship between the aramid core wire of the V-ribbed belt 50 of the comparative example 2 and the rib bottom 51a is arranged at an intermediate position between the embodiment and the comparative example 1.

Next, the experimental result about the influence which the height from the belt back surface of an aramid core wire has on the durability of a V-ribbed belt is demonstrated.
FIG. 4 shows the apparatus used for the first endurance test, which was performed in a room temperature environment. This apparatus has a driving pulley 61 and a driven pulley 62, and both the driving pulley 61 and the driven pulley 62 have a diameter of 60 mm. The rotational speed of the drive pulley 61 is 4900 RPM.

  The first endurance test was carried out twice with each of the pulleys 61 and 62 being wound around one of the V-ribbed belts 71, 72 and 73 shown in Table 2. The difference in configuration among the three V-ribbed belts is the height position of the aramid cord from the back of the belt, and the other configurations are common. Regarding the height from the center position of the aramid core to the back of the belt, the V-ribbed belt 71 is 0.74 mm at the lowest, the aramid core is located near the back of the belt, and the V-ribbed belt 73 is the highest at 1.63 mm. The V-ribbed belt 72 is 1.20 mm, and is located between the V-ribbed belt 71 and the V-ribbed belt 73.

  As shown in Table 2, in the first durability test, separation occurred between the aramid core wire and the ribs in the three V-ribbed belts 71, 72, 73, but the time from the start of the test to the occurrence of the failure was In contrast, the V-ribbed belt 73 was the longest, being 330 hours or longer.

  FIG. 5 shows the apparatus used for the second endurance test, which was conducted in a high temperature environment of 121 ° C. This device has a driving pulley 63, a driven pulley 64, a tensioner 65, and an idler 66. The driving pulley 63 and the driven pulley 64 both have a diameter of 120.65 mm, the tensioner 65 has a diameter of 44.45 mm, The diameter is 76.2 mm. The rotational speed of the drive pulley 63 is 4900 RPM.

  Similarly to the first durability test, the second durability test was performed twice by applying any of the V-ribbed belts 71, 72, and 73 shown in Table 2.

  As shown in Table 2, in the second endurance test, cracks occurred at the tips of the three V-ribbed belts 71, 72, 73, but the time from the start of the test to the occurrence of the failure was different. 73 was the longest and was 147 hours or longer.

  As described above, the durability of the V-ribbed belt can be improved by increasing the height position of the aramid core wire from the back of the belt, in other words, by determining the aramid core wire as close to the rib bottom as possible. Such a configuration can be achieved by an embodiment of the present invention in which the weft density and elongation of the intermediate canvas are appropriately determined as described above.

10 V-ribbed belt 11 Rib 12 Surface canvas 13 Back rubber 14 Intermediate canvas 15 Aramid cord 16 Adhesive rubber 17 Back member 21 Body rubber

Claims (8)

  A V-ribbed belt comprising a back rubber, an intermediate canvas, an adhesive rubber, an aramid core wire, a main body rubber, a surface canvas, and having a plurality of V-shaped ribs extending in the longitudinal direction of the belt on the main body rubber. The intermediate canvas provided on the back side of the belt is composed of a woven fabric composed of warp yarns extending in the belt longitudinal direction and weft yarns extending in the belt width direction, and the weft density of the intermediate canvas is 20 pieces / cm or more. V-ribbed belt characterized by the above.   2. The V-ribbed belt according to claim 1, wherein the weft density of the intermediate canvas is 24 / cm or more.   2. The V-ribbed belt according to claim 1, wherein an elongation ratio of the intermediate canvas in the extending direction of the weft is 100% / 2 Kgf · 2.5 cm or more.   The V-ribbed belt according to claim 3, wherein an elongation ratio of the intermediate canvas in the extending direction of the weft is 125% / 2 Kgf · 2.5 cm or more.   The V-ribbed belt according to claim 1, wherein a thickness of a back member made of the back rubber, the intermediate canvas, and the adhesive rubber is 1.30 mm or more.   The V-ribbed belt according to claim 5, wherein a thickness of the back member is 1.55 mm or more.   The V-ribbed belt according to claim 1, wherein a height from a center position of the aramid core wire to a surface of the back rubber is 1.0 mm or more.   V-ribbed belt manufacturing method comprising, from the inner peripheral side, an unvulcanized back rubber sheet and an intermediate canvas, each comprising a back rubber, intermediate canvas, adhesive rubber, aramid core, main body rubber, and surface canvas after molding A cylindrical slab intermediate layered in this order: jacket, unvulcanized adhesive rubber sheet, aramid core, unvulcanized main body rubber sheet, surface canvas jacket, and the surface canvas jacket face the inner peripheral wall of the outer mold. A method for producing a V-ribbed belt in which a plurality of V-shaped ribs extending in the longitudinal direction of the belt are formed on the main rubber by heating while pressing the cylindrical slab intermediate from the inner peripheral side, An intermediate canvas is provided on the belt rear side of the aramid cord, and is composed of a woven fabric comprising warps extending in the circumferential direction of the cylindrical slab intermediate and wefts extending in the axial direction of the cylindrical slab intermediate. The method of the V-ribbed belt, wherein the driving density of the weft is 20 present / cm or more.

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