JP2000193039A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase adhesion between a core wire and a rubber layer and provide an increased running life by reinforcing durability of a toothed belt. SOLUTION: A tooth part 14 and a bottom part 15 are alternately formed on one surface of the tooth rubber layer 12 of a toothed belt 10 and its outer surface is covered with canvass cloth 20. A back rubber layer 16 is integrally provided on the other surface of the toothed rubber layer 12. A core wire 18 is embedded in a boundary surface between the tooth rubber layer 12 and the back rubber layer 16. The tooth rubber layer and an adhesion rubber layer 22 having a composition different from that of a back rubber layer is formed between the core wire 18 and the tooth rubber layer 12 and the core wire 18 and the back rubber layer 16. The tooth rubber layer and the back rubber layer are formed of a compounded rubber prepared that a hydrogen peroxide vulcanizing agent is added in hydrogenated nitrile rubber having an iodine number of 11 or 28 and a compounded rubber prepared that an sulfur vulcanizing agent and a peroxide vulcanizing agent are added in hydrogenated nitrile rubber having an iodine number of 10 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt for transmitting torque to each shaft between an output shaft of an engine, an air conditioner, an alternator and the like in an internal combustion engine, for example.

[0002]

2. Description of the Related Art Conventionally, a toothed belt is provided with a tooth rubber layer, and a tooth portion and a tooth bottom portion are formed alternately in a longitudinal direction on one surface of the tooth rubber layer. A back rubber layer is integrally provided on the other surface of the tooth rubber layer, and a cord extending in the longitudinal direction is embedded between the tooth rubber layer and the back rubber layer.

In recent years, as the performance of internal combustion engines has improved,
As the number of revolutions of the crankshaft increases, a greater load is applied to the toothed belt used to rotationally drive various accessories. In addition, due to the downsizing and high load of the internal combustion engine, a more severe environment has arisen for the toothed belt.

[0004] Therefore, the toothed belt is required to have high heat resistance, be capable of transmitting a high load, and have a long life. For this reason, the raw rubber used for the tooth rubber layer and the back rubber layer has been switched from conventional chloroprene to hydrogenated nitrile rubber with excellent heat resistance, and in order to increase the heat resistance and rigidity of the toothed belt with elasticity, As a vulcanizing agent for rubber, a peroxide vulcanizing agent has been used instead of a conventional sulfur vulcanizing agent.

[0005]

However, when peroxide vulcanization is performed, the adhesion between the tooth rubber layer and the back rubber layer and the core wire is inhibited due to radicals generated from the peroxide vulcanizing agent. Therefore, there is a problem in that the toothed portion of the toothed belt has a shortage of teeth and the running life is shortened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has a long running life by strengthening the adhesion between the tooth rubber layer and the back rubber layer and the core wire and preventing chipping. The purpose is to obtain a belt with an attachment.

[0007]

According to the present invention, there is provided a toothed belt including a tooth rubber layer having a tooth portion and a tooth bottom portion alternately formed on one surface along a longitudinal direction, and a surface of the tooth portion and the tooth bottom portion. A covering canvas, a back rubber layer provided on the other surface of the tooth rubber layer, a plurality of core wires buried between the tooth rubber layer and the back rubber layer and extending in the longitudinal direction, and at least the core wire and the tooth rubber layer And an adhesive rubber layer having a rubber composition different from the rubber composition of the tooth rubber layer and the back rubber layer.

In the toothed belt, preferably, an adhesive rubber layer is provided both between the core wire and the tooth rubber layer and between the core wire and the back rubber layer.

In the toothed belt, the tooth rubber layer and the back rubber layer are preferably obtained from a compounded rubber obtained by adding a peroxide-based vulcanizing agent to a hydrogenated nitrile rubber having an iodine value of 11 to 28, and an adhesive rubber. The layer is preferably obtained from a compounded rubber obtained by adding a sulfur-based vulcanizing agent and a peroxide-based vulcanizing agent to a hydrogenated nitrile rubber having an iodine value of 10 or less.

[0010] In the toothed belt, it is preferable that the core wire includes a plurality of strands in which high-strength glass fiber filaments are bundled and twisted. Furthermore, a predetermined number of strands among these multiple strands are bundled,
The remaining strands are regularly arranged around the predetermined number of strands, and all the strands are twisted while being tensioned in the longitudinal direction. An overcoat layer made of a rubber paste solution of chlorosulfonated polyethylene may be formed on the core wire.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a toothed belt according to an embodiment of the present invention.

FIG. 1 shows a toothed belt according to a first embodiment. In the figure, a cut-away part of the toothed belt 10 is shown as a perspective view. FIG. 2 shows a partially enlarged sectional view of the tooth bottom 15 shown in FIG.

The toothed belt 10 has a tooth rubber layer 12,
On one surface of the tooth rubber layer 12, tooth portions 14 and tooth bottom portions 15 are alternately and integrally formed along the longitudinal direction. The outer surfaces of the tooth portions 14 and the tooth bottom portions 15 of the tooth rubber layer 12 are covered with canvas 20. This canvas 20 is formed as a folded cloth made of aramid fiber and nylon fiber.

On the other side of the tooth rubber layer 12, the back rubber layer 1
6 are provided. A plurality of cords 18 are embedded between the tooth rubber layer 12 and the back rubber layer 16. The cord 18 is parallel to the longitudinal direction of the toothed belt 10. The cord 18 is obtained, for example, by spirally winding a pair of cords along the longitudinal direction of the toothed belt 10. At this time, one of the pair of cords is an S-strand cord, and the other is a Z-strand cord.

An adhesive rubber layer 22 having good adhesion to the core wire 18 is provided around the core wire 18, that is, at the boundary between the tooth rubber layer 12 and the back rubber layer 16. That is, the tooth rubber layer 12
An adhesive rubber layer 22 intervenes between the core wire 18 and the backing rubber layer 16, and an adhesive rubber layer 22 also intervenes between the back rubber layer 16 and the core wire 18.

In the tooth bottom 15, as is apparent from FIG. 2, the thickness Th of the adhesive rubber layer 22 is larger than the diameter d of the core wire 18, and the core wire 18 is completely embedded in the adhesive rubber layer 22. . Adhesive rubber layer 22 located inside tooth portion 14
Project along the top of the teeth 14.

Conventionally, a toothed belt capable of sufficiently withstanding running under a high load could not be obtained due to low adhesion between the tooth rubber layer and the back rubber layer and the core wire. In the attached belt 10, the tooth rubber layer 12 and the core 1
8, and since the adhesive rubber layer 22 is provided as an adhesive between the back rubber layer 16 and the core wire 18, the running life thereof can be extended as compared with the conventional toothed belt.

Such a toothed belt 10 is manufactured, for example, as follows. As shown in FIG. 3, a canvas material 20 'having a predetermined length is preformed in a corrugated shape in advance, and a compound rubber sheet 12' and a compound rubber sheet 22 'are formed.
Is preformed integrally with the canvas material 20 'according to the shape of the canvas material 20'. Preformed compound rubber sheet 1
In 2 ', tooth portions 14' and tooth bottom portions 15 'are formed alternately. The pre-formed intermediate product is formed on the forming drum 3
4 and the cut edges are brought into contact with each other. On the forming drum 34, a tooth portion 36 and a tooth bottom portion 38 corresponding to the contour shape of the toothed belt 10 are formed.

The fabric material 20 ′, the compound rubber sheet 12 ′ having the tooth portions 14 ′ and the tooth bottom portions 15 ′, and the compound rubber sheet 22 ′ are formed on the canvas 20, the tooth portions 14 and the tooth bottom portion of the finished toothed belt 10, respectively. Tooth rubber layer 1 with 15
2, and the adhesive rubber layer 22.

A pair of cords 18 'are spirally wound around the intermediate product wound around the forming drum 34, and the compound rubber sheet 2 is wound around the outer periphery of the cord 18'.
2 ′ and compound rubber sheet 1 to be back rubber layer 16
6 'is wound. Thereafter, the belt component 12 ',
The forming drum 34 having 16 ', 18', 20 'and 22' is placed in a vulcanization oven (not shown), where it undergoes a vulcanization process at a predetermined temperature and pressure. By this vulcanization, the belt components 12 ', 16', 18 ', 2
The gap between 0 'and 22' is removed.

As shown in FIG. 4, the vulcanization process vulcanizes and forms a cylindrical toothed belt strob 10 '. The toothed belt stub 10 'is taken out of the vulcanizing oven, polished by a grinder or the like, and then cut into an appropriate width in a ring shape. By the above-described processing, a finished toothed belt 10 having a desired width is obtained. In FIG. 6, each component of the toothed belt stub 10 'is denoted by the same reference numeral as each component of the finished toothed belt 10.

A hydrogenated nitrile rubber having an iodine value of 11 to 28 is used as a raw material rubber for the tooth rubber layer 12 and the back rubber layer 16, and an organic peroxide is used as a vulcanizing agent for the hydrogenated nitrile rubber. A hydrogenated nitrile rubber having an iodine value of 10 or less is used as a raw material rubber for the adhesive rubber layer 22. As a vulcanizing agent for the adhesive rubber layer 22,
A peroxide to which sulfur is added is used.

Hydrogenated nitrile rubber is a material having excellent heat resistance, and it is known that the lower the iodine value, the better the heat resistance. While the toothed belt 10 is running,
Since the most load is applied around the core 18, the core 18
The rubber layer surrounding the core wire 18 is likely to be heated to a high temperature, deteriorates, and the adhesive force at the interface with the core wire 18 becomes weak. For this reason, a hydrogenated nitrile rubber having an iodine value lower than that of the hydrogenated nitrile rubber of the tooth rubber layer 12 and the back rubber layer 16, that is, excellent heat resistance, is used as the raw rubber of the adhesive rubber layer 22.

It is well known that when a hydrogenated nitrile rubber is vulcanized only with a peroxide, the heat resistance is better than when a hydrogenated nitrile rubber having the same iodine value is vulcanized with a sulfur-added peroxide. is there. However, for example, the adhesive rubber layer 2
When only peroxide is used as the vulcanizing agent of 2, the heat resistance is good, but the adhesiveness to the core wire 18 is reduced, and the vulcanizing agent is not suitable for the toothed belt 10. Therefore, in the present embodiment, a peroxide containing sulfur is used as a vulcanizing agent for the adhesive rubber layer 22, and
8 is improved.

If the adhesive rubber layer 22, the tooth rubber layer 12 and the back rubber layer 16 have the same iodine value of the hydrogenated nitrile rubber, and the adhesive rubber layer 22 is made of sulfur-added peroxide. And the tooth rubber layer 12 and the back rubber layer 1
If only the peroxide is used as the vulcanizing agent of No. 6, the core wire 18
The adhesive rubber layer 22 has good adhesiveness with the adhesive rubber layer 22, but the heat resistance of the adhesive rubber layer 22 is inferior to the tooth rubber layer 12 and the back rubber layer 16, and the durability of the toothed belt 10 cannot be expected to be improved.

However, the tooth rubber layer 12 and the back rubber layer 16
By using a hydrogenated nitrile rubber having an iodine value lower than that of the hydrogenated nitrile rubber for the adhesive rubber layer 22, the adhesive rubber layer 22 having heat resistance equal to or higher than that of the tooth rubber layer 12 and the back rubber layer 16 can be obtained. You can get
The adhesiveness between the core wire 18 and the adhesive rubber layer 22 can be improved, and the durability of the toothed belt 10 can be dramatically improved.

From the above, the heat resistance of the adhesive rubber layer 22 is equal to the heat resistance of the tooth rubber layer 12 and the back rubber layer 16.
Alternatively, the iodine value of the hydrogenated nitrile rubber used for the adhesive rubber layer 22 and the amount of sulfur added as a vulcanizing agent are appropriately determined so as to be more than that.

Further, as described above, the toothed belt 10
Since the components 12, 16, 18, and 22 are vulcanized at once, the adhesive rubber layer 22, the tooth rubber layer 12, and the back rubber layer 16 are so formed that the vulcanization rates of the components are substantially equal. , The amount of the vulcanizing agent mixed with the raw rubber is determined. This is because if the vulcanization rates of the respective components are different, vulcanization and adhesion of the respective components are not performed properly, that is, the tooth rubber layer 12 and the adhesive rubber layer 22, the back rubber layer 16 and the adhesive rubber layer 22, or Rubber layer 22
This is because poor bonding occurs at the boundary surface between the wire 18 and the core wire 18.

The canvas 20 is formed from a woven cloth twilled with composite yarns along the longitudinal direction of the toothed belt 10 and non-stretchable yarns along the width direction of the toothed belt 10, but other woven cloths For example, it may be formed by a woven cloth obtained by satin weave, plain weave, or various modified weaves.

The composite yarn of the canvas 20 includes, for example, a core yarn, a spun yarn wrapped around the core yarn, and a crimped yarn wrapped around the core yarn in a direction opposite to the winding direction of the spun yarn. It consists of. A polyurethane elastic yarn is preferably used as the core yarn, an aramid fiber having excellent heat resistance is used as the spun yarn, and a nylon fiber of an aliphatic synthetic fiber having excellent wear resistance is suitably used as the crimped yarn. The non-stretchable yarn of the canvas 20 preferably has excellent rigidity and heat resistance, and for example, a filament yarn of nylon fiber is suitable.

As described above, in the canvas 20, the composite yarn having elasticity is used along the longitudinal direction of the toothed belt 10, and the non-elastic yarn is used along the width direction of the toothed belt 10. Thereby, the toothed belt 10 is attached to the canvas 20.
Is provided along the longitudinal direction, thereby improving abrasion resistance and heat resistance.

FIG. 5 shows one of the pair of cords constituting the cord 18, that is, the S-strand cord 30 partially cut away. FIG. 6 is a cross-sectional view of the S twisted core cord 30. For example, high-strength glass fiber is suitably used for the core wire 18.

First, filaments 32, which are high-strength glass fibers having a small diameter, are converged into, for example, 200 filaments to form one thread 34. The diameter of the high strength glass fiber is preferably 7
μm. Each filament 32 is subjected to a treatment for waterproofing or the like, for example, a treatment with resorcin-formalin-latex, that is, an RFL solution. More specifically, three yarns 34 in which many filaments 32 are converged are collected,
These three yarns 34 are dried after being immersed in the RFL solution, whereby the RF 32 is applied to each filament 32.
An L layer is formed. Thereafter, these three yarns 34 are twisted in the Z direction to form one strand 38.

Further, as shown in FIG. 6, a core is formed by collecting three strands 38, and eight strands 38 are evenly arranged around the core. In the core, the three strands 38 are arranged such that the three centers 38a form an equilateral triangle. In the eight strands 38 arranged around the core, the centers 38b of the respective strands 38b are located at positions substantially equal to each other from the center of the S-strand core cord 30, and the centers 38b of two adjacent strands 38 are arranged. The circumferential distances between them are all equal and the distance S. In FIG. 6, the center 38b is shown only for the four strands 38.

The number of core strands 38 or the number of strands 38 around the core is not particularly limited to three or eight. Also, the arrangement of the strands 38 in the core is not limited to the arrangement shown in FIG. 6, but it is desirable that the strands 38 be arranged so that the gaps in the core are reduced when the strands 38 having a substantially circular cross section are collected. .

While tension is applied to these 11 strands 38, the upper strands are twisted in the direction opposite to the bottom twist, that is, twisted in the S direction. Thus, the S twisted core cord 30 is obtained. Further, the S twisted core cord 30
After being immersed in a rubber paste solution of chlorosulfonated polyethylene, it is dried, so that an overcoat layer 40 can be formed on the outer periphery of each strand 38. Overcoat layer 4
By providing 0, the adhesiveness of the S twisted core cord 30 to the adhesive rubber layer 22 or the back rubber layer 16 is improved.

With respect to the Z twisted core cord (not shown) that is paired with the S twisted core cord 30, the S twisted core shown in FIG. 5 is used except that the lower twist is S twist and the upper twist is Z twist. It is substantially the same as the line code 30. The S twisted core cord 30 and the Z twisted core cord thus obtained are combined and used as the core wire 18.

Conventionally, in the first twist, a plurality of strands are arranged at random and are simply twisted in the opposite direction to the first twist. It is unavoidable that the gap in the line, that is, the gap between the strands is also uneven and large. However, in the present embodiment, since the strands 38 are regularly arranged at the time of the first twist, the tension is evenly applied to each strand 38, and the gap between the adjacent strands 38 is reduced. That is, the degree of adhesion between the strands 38 is improved as compared with the related art, and the gap in the core wire 18 is reduced. Therefore, core 1
8, the water from the outside is less likely to stay inside the core wire 18, and the water resistance of the core wire 18 is improved.

Due to the structure of the toothed belt 10, water hardly enters from the canvas 20 side and the backing rubber layer 16 side. However, since the core wire 18 is exposed on the side surface, the core wire 18 is capillarized. It is known that water easily enters the interior of the building. When water enters the core wire 18, the treatment agent used for the RFL layer and the like swells and deteriorates, which may cause deterioration of the core wire 18 itself. However, the core wire 18 of this embodiment
Has improved water resistance due to the configuration as described above,
Deterioration due to water intrusion is prevented.

Referring to FIG. 7, a second embodiment of the present invention is shown, in which components corresponding to those of the toothed belt shown in FIG. 1 are indicated using the same reference numerals. FIG. 7 shows a partially enlarged sectional view of the tooth bottom 15. In the second embodiment, the adhesive rubber layer 22 is provided only between the core wire 18 and the tooth rubber layer 12, and other than this point, the second embodiment is substantially the same as the first embodiment. is there. That is, the core wire 18 has a diameter d on the tooth rubber layer 12 side.
About one-half of the adhesive is embedded in the adhesive rubber layer 22, and the remaining about one-half
/ 2 are embedded in the back rubber layer 16.

In order to obtain the toothed belt 10 of the second embodiment, in the manufacturing process (see FIG. 3), the forming drum 34
Only the cord 18 'and the compounded rubber sheet 16' are wound around the intermediate product wound around, and the compounded rubber sheet 22 'is not wound as in the first embodiment. Thereby, the toothed belt 10 in which the adhesive rubber layer is not provided between the core wire 18 and the back rubber layer 16 is obtained.

Also in the second embodiment, the adhesive rubber layer 22
Is provided between the core wire 18 and the tooth rubber layer 12, the adhesiveness at the boundary between the core wire 18 and the tooth rubber layer 12, which is the most loaded, is improved, and the toothed belt 10 having a long life is obtained. be able to.

[0043]

The present invention will be described below with reference to examples and comparative examples. The present invention is not limited by these examples.

[Compounded Rubber and Compounded Rubber Sheet] As shown in Table 1 below, three kinds of compounded rubbers A to C to be used for the toothed belt were prepared.

[Table 1]

In Table 1, * 1 to * 7 represent the following items. * 1, * 2, * 3 Trade name of Nippon Zeon Co., Ltd., ethylenically unsaturated nitrile-conjugated diene-based highly saturated polymer rubber * 4 Hydrogenation rate is percentage (unit is%) * 5 Iodine value is innumerable * 6 Types of compounding materials and parts by weight of compounding materials with respect to 100 parts by weight of rubber raw material (unit is phr) * 7 Peroxide vulcanization composed of dicumyl peroxide and 1,3-bis (t-butylperoxy-isopropyl) benzene Agent (the former is available as Die Cup 40C manufactured by Hercules, and the latter is available as Peroximon F40 manufactured by NOF Corporation).

As is clear from Table 1, the compounded rubber A is 1 part by weight of stearic acid and 10 parts by weight with respect to 100 parts by weight of a hydrogenated nitrile rubber having a hydrogenation rate of 99% and an iodine value of 4 as a rubber raw material. Parts by weight of zinc oxide, 1.5 parts by weight of an antioxidant, 20 parts by weight of carbon black, 25 parts by weight of
1 part by weight of zinc methacrylate, 15 parts by weight of a peroxide-based vulcanizing agent, 1.8 parts by weight of sulfur, and 10 parts by weight of a plasticizer. The compounded rubber sheet (A) was obtained from the compounded rubber A by extrusion molding, and then the compounded rubber sheet (A) was vulcanized.

The compounded rubber B was prepared by mixing 100% of a hydrogenated nitrile rubber having a hydrogenation rate of 90% and an iodine value of 28 as a rubber raw material.
1 part by weight of stearic acid, 5 parts by weight of zinc oxide, 1 part by weight of an antioxidant, 60 parts by weight of carbon black, 0.5 parts by weight of sulfur, and 7
It is obtained by adding parts by weight of a vulcanization aid and 10 parts by weight of a plasticizer. A compound rubber sheet (B) was obtained from the compound rubber B by extrusion molding, and the compound rubber sheet (B) was vulcanized.

The compounded rubber C was prepared by mixing 100% of a hydrogenated nitrile rubber having a hydrogenation rate of 95% and an iodine value of 11 as a rubber raw material.
1 part by weight of stearic acid, 10 parts by weight of zinc oxide, 1.5 parts by weight of an antioxidant, 20 parts by weight of carbon black, 25 parts by weight of zinc methacrylate, It contains 18 parts by weight of a peroxide-based vulcanizing agent, 6 parts by weight of a vulcanization aid, and 10 parts by weight of a plasticizer. After a compound rubber sheet (C) was obtained from the compound rubber C by extrusion molding, the compound rubber sheet (C) was vulcanized.

Next, the compounded rubber sheet (A) described above,
Samples for an adhesive strength test were prepared from (B) and (C), and an adhesive strength test with a core wire was performed using each sample.

[Sample Piece for Adhesive Strength Test] FIG. 8 is a perspective view of a sample piece 50 used for the adhesive strength test.
As an example of manufacturing the sample piece 50, a method of manufacturing the sample piece 1 of the embodiment will be described. First, a compound rubber sheet (A) having a width of 25 mm and a length of 120 mm is prepared as a rubber sheet 52. Twenty-eight cords 54 are arranged on the rubber sheet 52, and a cloth 56 is additionally put on the cords 54. In this state, the sample is heated and pressed by a press, whereby a sample piece 50, that is, a sample piece 1 of the embodiment is obtained.

In the adhesive strength test between the core wire 54 and each compound rubber sheet, the core wire B shown in Table 2 was used as the core wire 54.
Was used.

[Table 2]

The core B will be specifically described. First, a yarn in which 200 high-strength glass fibers having a diameter of 7 μm were converged into 3
After being collected and subjected to the RFL treatment, the strand was Z-twisted (S-twisted) and twisted to form a strand. Further, 11 of these strands were randomly collected and subjected to a top twist in an S twist (Z twist), which is the opposite direction to the bottom twist, to form an S (Z) twisted core cord. Further, each cord was overcoated with a rubber solution of chlorosulfonated polyethylene. A pair of S twisted core cord and Z twisted core cord are spirally wound,
This was designated as cord B.

The configuration and processing of the comparative sample 1 are the same as those of the example 1 except that the compound rubber sheet (B) is used as the rubber sheet 52.

The structure and processing of the comparative sample 2 are the same as those of the example 1 except that the compound rubber sheet (C) is used as the rubber sheet 52.

[Adhesive Strength Test and Its Evaluation] FIG. 9 shows a state where the sample piece 50 is attached to a tensile tester. The test method will be described with reference to FIG. At one end of the sample piece 50, a cut is made between the core wire 54 and the rubber sheet 52 so that the surface of the core wire 54 looks uniform. The end of the stripped core wire 54 and the end of the rubber sheet 52 are attached to a chuck 58, respectively, and pulled at a pulling speed of 50 mm per minute by a tensile tester. The adhesive strength is evaluated by measuring the peeling force between the core wire 54 and the rubber sheet 52.

In the adhesive strength test, the test piece 50 in the normal state was used.
And the heat treatment of the test piece 50. The normal sample piece 50 is a sample piece immediately after being manufactured as described above, and was tested in a normal temperature environment. The specimen 50 after the heat resistance test was manufactured as described above,
This is a heat-treated sample piece that is left for 280 hours in an environment of 0 ° C. After the sample piece 50 returned to normal temperature, the test was performed in a normal temperature environment.

The results of the adhesive strength test are shown in the lower part of Table 3 below. In addition, in Table 3, "..." shows that the rubber sheet 52 was broken at the time of measurement and measurement was impossible.

[0058]

[Table 3]

As is clear from Table 3, in the measurement in the normal state, the adhesive force between the compound rubber sheet and the core wire of the sample sample 1 of the example and the sample sample 1 of the comparative example is much larger than that of the sample sample 2 of the comparative example. . The reason for this is that in Example Sample 1, a sulfur-added peroxide was used as a vulcanizing agent, and in Comparative Sample 1, only sulfur was used, whereas in Comparative Sample 2, peroxide was used as a vulcanizing agent. It is considered that the adhesiveness was inferior because of using only.

In the measurement after the heat treatment, the adhesive strength of the sample 1 of the example was much higher than that of the sample 2 of the comparative example, and the sample 1 of the comparative example was broken and could not be measured. It is considered that the reason for this is that the heat resistance of the comparative sample 2 was poor because only sulfur was used as the vulcanizing agent.

That is, the compounded rubber sheet (A) using a sulfur-added peroxide as a vulcanizing agent has both a high adhesive force in a normal state and an adhesive force after heat aging, and the toothed belt 10
Is most suitable for the adhesive rubber layer 22 provided around the core wire 18. The compounded rubber sheet (B) using only sulfur as a vulcanizing agent has high adhesiveness at normal temperature but low adhesive strength after heat aging, and has an adhesive rubber layer 22 of a toothed belt used at high temperature. Not suitable. Further, the compounded rubber sheet (C) using only peroxide as a vulcanizing agent has insufficient adhesive strength to the core wire at both normal temperature and high temperature environment, and is not suitable for the adhesive rubber layer 22.

As described above, the adhesive strength test shows that the compounded rubber sheet (A) is most suitable for the adhesive rubber layer 22 used as the adhesive for the cord 18 of the toothed belt 10.

[Example Belt and Comparative Example Belt] By using the above-mentioned three types of compounded rubber sheets (A), (B) and (C), three types of examples of the toothed belt according to the present invention were obtained. These three types of toothed belts are referred to below as example belts 1, 2, and 3, respectively. Two types of toothed belts were also produced as comparative examples of the toothed belt according to the present invention, and these were the comparative belts 1 and 2
As below.

The structures of the example belt 1 and the comparative example belts 1 to 4 are as shown in Table 4 below.

[Table 4]

Example belt 1: As shown in Table 4, in Example belt 1, a compound rubber sheet (C) was used as the tooth rubber layer 12 and the back rubber layer 16, and a compound rubber sheet (A) was used as the adhesive rubber layer 22. ) Was used. The adhesive rubber layer 22 was provided on both the tooth rubber layer 12 side and the back rubber layer 16 side of the core wire 18. As the canvas 20, the one having the folded fabric structure as described above, that is, the canvas A shown in Table 5 was used.

[0066]

[Table 5]

Specifically, the canvas A is a 2/2 twill woven fabric, and its elastic composite yarn is a longitudinal yarn.
Its density is 150 lines / 5 cm. A 420 d urethane elastic yarn is used as a core yarn for each composite yarn, and a 200 d aramid fiber spun yarn is wound around this core yarn at a rate of 650 turns / m in one direction, and further wound outside the core yarn. A 100-d 6,6-nylon yarn was wound in the opposite direction to the spun aramid fiber yarn as a crimped yarn. On the other hand, a 100-d 6,6-nylon yarn is used as the non-stretchable widthwise yarn, and its density is 170/5 cm.

The canvas A is preliminarily subjected to a canvas treatment with a resorcinol-formaldehyde latex (RFL) solution. That is, after being immersed in the RFL solution, a drying treatment is performed to form an RFL layer on the surface of the canvas, thereby enhancing the adhesiveness to the compounded rubber sheet. The latex component of the RFL solution is a carboxylated nitrile rubber.
Chlorophenol formaldehyde condensate in FL solution,
For example, 2,6-bis (2,4-dihydroxyphenylmethyl) -4-chlorophenol derivative polymer (trade name;
(Valca Bond E, manufactured by ICI-VULNAX).

In the belt 1 of the embodiment, the cord A shown in Table 2 was used as the cord 18. The core A has the configuration of the core 18 described above, and is substantially the same as the core B except that the way of twisting is different.

The twisting is described in detail. A core is formed by collecting three strands, and eight strands 38 are evenly arranged around the core (FIG. 5). These 11
The strand of the book was twisted in the S (Z) direction while applying tension.

Example belt 2: As shown in Table 4, in Example belt 2, a compound rubber sheet (C) was used as the tooth rubber layer 12 and the back rubber layer 16 in the same manner as in Example belt 1, and the adhesive rubber was used. Compounded rubber sheet (A) as layer 22
Was used. The adhesive rubber layer 22 is the tooth rubber layer 1 of the cord 18.
It was provided only on two sides. The core A was used as the core 18, and the canvas A was used as the canvas 20. The example belt 2 is substantially the same as the example belt 1 except that the adhesive rubber layer 22 is not provided on the back rubber layer 16 side of the core wire 18.

Example belt 3: As shown in Table 4, in Example belt 3, a compound rubber sheet (C) was used as the tooth rubber layer 12 and the back rubber layer 16 in the same manner as in Example belt 2, and the adhesive rubber was used. Compounded rubber sheet (A) as layer 22
Was used. The adhesive rubber layer 22 was provided only on the side of the tooth rubber layer 12 of the cord 18 as in the belt 2 of the embodiment. Cord 1
The core wire B was used as 8, and the canvas A was used as the canvas 20. The example belt 3 is substantially the same as the example belt 2 except that the core wire 18 is used as the core wire 18.

Comparative Example Belt 1: As shown in Table 4, in Comparative Example Belt, a compound rubber sheet (C) was used as the tooth rubber layer 12 and the back rubber layer 16 in the same manner as in Example belt 1, and the adhesive rubber was used. Layer 22 was not provided. Cord 1
The core wire A was used as 8, and the canvas A was used as the canvas 20. The comparative example belt 1 is substantially the same as the example belt 1 except that the adhesive rubber layer 22 is not provided.

Comparative Example Belt 2: As shown in Table 4, in Comparative Example Belt 2, the tooth rubber layer 12 and the back rubber layer 16
Rubber compound (B) is used as the adhesive rubber layer 2
2 was not provided. The core wire B was used as the core wire 18, and the canvas B shown in Table 5 was used as the canvas 20. The comparative example belt 2 is substantially the same as the example belt 1 except that the cord B and the canvas B are used for the cord 18 and the canvas 20, respectively, and that the adhesive rubber layer 22 is not provided. Things.

The canvas B is substantially the same as the canvas A except that the yarns in the longitudinal direction and the width direction are different. A 420d 6,6-nylon crimped yarn is used for the yarn in the longitudinal direction, and its density is 170 yarns / 5 cm. As the yarn in the width direction, 210d 6,6-nylon yarn is used, and its density is 170 yarns / 5 cm.

[Running Test of Toothed Belt and Its Evaluation] Using the five types of toothed belts as described above, ie, Example belts 1 to 3 and Comparative example belts 1 and 2,
And a second running test.

FIG. 10 is a diagram showing a schematic configuration of the first traveling test device. The first running test device consists of three toothed wheels 62, 64 and 66 and a tensioner 68 provided between the toothed wheels 66 and 62. The toothed belt 61 to be tested comprises three toothed wheels 62, 64 and 66 and a tensioner 6 in the manner shown in FIG.
It is bridged with 8.

In the first running test apparatus, running tests were performed on the example belts 1, 2 and 3 and the comparative example belts 1 and 2 under the same conditions. For the evaluation of the running test, the running time of each toothed belt from the start of running to the occurrence of tooth loss was measured.

The results of the first running test are shown in the lower part of Table 4. The running time of the example belt 1 is 700 hours,
The running time of the example belt 1 was 576 hours, and the running time of the example belt 1 was 487 hours. In contrast, the running times of the comparative example belts 1 and 2 were only 349 hours and 32 hours, respectively.

From the above results, it can be seen that Examples 1 to 3 in which the adhesive rubber layer was provided at least on the tooth rubber layer had better durability than Comparative Examples 1 and 2 in which the adhesive rubber layer was not provided. I understand. In particular, it is clear that the example belt 1 in which the adhesive rubber layer is provided on both the tooth rubber side and the back rubber side has the best durability. Also, comparing Example belts 2 and 3 which differ only in the configuration of the core, the core A
It can be seen that the belt 2 of the embodiment using the belt has better durability than the belt 3 of the embodiment using the core wire B.

FIG. 11 is a view showing a second running test apparatus. The second running test device comprises two toothed wheels 72
And 74, and a tensioner 76 provided between the toothed wheels 74 and 72. The toothed belt 71 to be tested is stretched over two toothed wheels 72 and 74 and a tensioner 76 in a manner as shown in FIG. Water is injected between the toothed wheel 72 and the test toothed belt 71 at a rate of 1 L per hour.

In the second running test apparatus, the belt
For each of 3 and 3, the running test was performed twice under the same conditions. For the evaluation of the running test, the belt tensile strength before running and the belt tensile strength after running test were measured, respectively, the ratio of the belt tensile strength after running test to the belt tensile strength before running,
That is, the belt tensile strength remaining retention was determined.

The results of the second running test are shown at the bottom of Table 4. In Table 4, each numerical value represents the residual tensile strength retention ratio, and the unit is%. In the table, "#
## ″ indicates that the running test was not performed.

The residual belt tensile strength retention of the belt 2 was 66% and 61%, whereas the residual belt tensile retention of the belt 3 was only 50% and 45%. The belt tensile strength of the belt 2 did not reach the retention rate.

The difference between the belts 2 and 3 is
The embodiment belt 2 in which the core wire A is used is different from the embodiment belt 3 in which the core wire A is not used, only in the point of whether or not the core wire A is used. It can be seen that the residual retention rate is high and the water resistance is excellent.

According to the results of the above two running tests, the cord 1
It has been shown that the durability of the belt is significantly improved by providing the adhesive rubber layer 22 around the periphery of the belt 8, and the water resistance of the belt is improved by reducing the gap in the cord 18.

[0087]

According to the present invention, it is possible to obtain a toothed belt having a long running life by strengthening the adhesion between the tooth rubber layer and the back rubber layer and the core wire and preventing chipping.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a first embodiment of a toothed belt according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing an enlarged cross-sectional view of a tooth bottom portion of the toothed belt shown in FIG.

FIG. 3 is a schematic process diagram showing a winding process of a core cord and a winding process of a compound rubber sheet in the manufacturing process of the toothed belt according to the present invention.

FIG. 4 is a schematic process chart showing a vulcanizing step in the manufacturing process of the toothed belt according to the present invention.

FIG. 5 is a perspective view showing a part of the cord shown in FIG.

FIG. 6 is a sectional view of the cord shown in FIG. 1;

FIG. 7 is a partial side view showing a second embodiment of the toothed belt according to the present invention.

FIG. 8 is a view showing a sample piece used in a test for evaluating the adhesive strength between a cord and a compound rubber.

9 is a diagram showing a state where the sample piece shown in FIG. 8 is attached to a tester.

FIG. 10 is a schematic view of a first running test apparatus for performing a running test of the example belt and the comparative example belt according to the present invention.

FIG. 11 is a schematic view of a second running test apparatus for performing a running test of the example belt and the comparative example belt according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Toothed belt 12 Tooth rubber layer 14 Tooth part 15 Tooth bottom part 16 Back rubber layer 18 Core wire 20 Canvas 22 Adhesive rubber layer

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[Procedure amendment]

[Submission date] January 28, 2000 (2000.1.2
8)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

According to the present invention, there is provided a toothed belt including a tooth rubber layer having a tooth portion and a tooth bottom alternately formed on one surface along a longitudinal direction, and an outer surface of the tooth portion and the tooth bottom. Canvas, a back rubber layer provided on the other surface of the tooth rubber layer, a plurality of core wires buried between the tooth rubber layer and the back rubber layer and extending in the longitudinal direction, and at least the core wire and the tooth rubber Between the rubber layer of the tooth rubber layer and the back rubber layer, an adhesive rubber layer having a rubber composition different from that of the tooth rubber layer,
The backing rubber layer is a hydrogenated nitrile having an iodine value of 11 to 28.
Obtained from compounded rubber obtained by adding peroxide-based vulcanizing agent to rubber
Hydrogenated nitrile with an iodine value of 10 or less
Sulfur vulcanizing agent and peroxide vulcanizing agent added to rubber
Obtained from compounded rubber is characterized in Rukoto.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Deleted

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Tezuka 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Research Institute, Ltd. (72) Inventor Junji Yokoi 172 Ikezawa-cho, Yamatokoriyama-shi, Nara Unita Co., Ltd.

Claims (5)

[Claims] 1. A tooth rubber layer in which tooth portions and a tooth bottom portion are alternately formed on one surface along a longitudinal direction; a canvas covering an outer surface of the tooth portion and the tooth bottom portion; A back rubber layer provided on the other surface, a plurality of core wires buried between the tooth rubber layer and the back rubber layer and extending in the longitudinal direction, at least between the core wire and the tooth rubber layer And a bonding rubber layer having a rubber composition different from that of the tooth rubber layer and the back rubber layer. 2. The adhesive rubber layer according to claim 1, wherein the adhesive rubber layer is provided both between the core wire and the tooth rubber layer and between the core wire and the back rubber layer. Toothed belt. 3. The tooth rubber layer and the back rubber layer are obtained from a compounded rubber obtained by adding a peroxide-based vulcanizing agent to a hydrogenated nitrile rubber having an iodine value of 11 to 28, and the adhesive rubber layer is formed of iodine. The toothed belt according to claim 1, wherein the belt is obtained from a compounded rubber obtained by adding a sulfur-based vulcanizing agent and a peroxide-based vulcanizing agent to a hydrogenated nitrile rubber having a value of 10 or less. 4. The core wire comprises a plurality of strands obtained by bundling high-strength glass fiber filaments and twisting, and a predetermined number of strands are bundled among the plurality of strands, and the predetermined number of strands are bundled. 2. The toothed belt according to claim 1, wherein the remaining strands are regularly arranged around the center, and all the strands are twisted while being tensioned in the longitudinal direction. 3. 5. The toothed belt according to claim 4, wherein an overcoat layer of a rubber paste solution of chlorosulfonated polyethylene is formed on the core wire.