JP3113599B2 - Transmission belt - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission belt, and more particularly, to a reinforcement of a compressed rubber layer which is repeatedly compressed when the belt runs.

[0002]

2. Description of the Related Art In order to improve the lateral pressure resistance of a compressed rubber layer of a V-belt, it is common practice to mix and disperse organic short fibers in the rubber to improve the elastic modulus in the belt width direction. In order to increase the modulus of elasticity of the compressed rubber layer, a large amount of short fibers may be used. However, in this case, the flexibility of the rubber layer is reduced, and the tire is easily fatigued. For this reason, even if the amount of the short fiber is as small as possible, and yet a high elastic modulus is obtained in the compression rubber layer, using a short fiber having a high elastic modulus,
Further, it is necessary to reduce the amount of the short fibers mixed in the compressed rubber layer by reducing the diameter of the short fibers.

On the other hand, it is known to use aramid fiber having a high elastic modulus or nylon fiber as a reinforcing short fiber of a compressed rubber layer, and further use relatively inexpensive general-purpose vinylon fiber. It is also being considered.

[0004]

However, in the case of the above-mentioned aramid short fibers, there are problems in terms of workability and dispersibility in rubber, and it is difficult to impart flex fatigue resistance to the belt. In the case of the above nylon fiber, although the dispersibility of the nylon fiber itself is relatively good, there is a problem in terms of heat bending fatigue resistance because the elastic modulus has a high temperature dependency.

[0005] In the case of the above vinylon fiber, although it is inexpensive, the amount of fiber for obtaining the same elastic modulus as that of the aramid fiber is large, and itself is hardly dispersible. For this reason, the vinylon fibers are apt to be unevenly distributed in the compressed rubber layer and are likely to be agglomerated. In such a portion, the fibers are melted by the heat generated by the running of the belt and are converted into foreign matters, thereby lowering the flexibility of the belt. . It is considered that the melting of the vinylon fibers is affected by the moisture in the rubber.

On the other hand, when the diameter of the reinforcing short fiber is reduced as described above, the end of the short fiber exposed from the side of the compressed rubber layer of the V-belt tends to fall due to contact with the pulley. For this reason, if the rubber on the side of the compressed rubber layer softens due to frictional heat with the pulley and generates plastic flow, the softened and flown rubber will cover the fallen short fibers. This short fiber is required to not only increase the elastic modulus of the compressed rubber layer but also to play a role of giving an appropriate coefficient of friction between the belt and the pulley by contact with the pulley. If the belt and the pulley are covered, the coefficient of friction between the belt and the pulley increases, causing chatter (rattle) between the belt and the pulley and generating abnormal noise.

On the other hand, when the diameter of the short fiber is increased, the above-mentioned collapse is reduced, but the aspect ratio of the short fiber is reduced by the increase in the diameter. You need to increase the amount of fiber to get
This causes an increase in cost and a reduction in dynamic fatigue life.

[0008] That is, an object of the present invention is to improve the dynamic fatigue life of the power transmission belt without reducing the workability of the rubber (the dispersibility of the fibers) when using short reinforcing fibers in the compressed rubber layer. Is to stabilize the coefficient of friction.

[0009]

In order to solve such a problem, the present inventor has proposed that when two types of short fibers having different physical properties are used in combination, that is, as a reinforcing short fiber, high strength (or high elasticity) is obtained. Short fibers are used, but not all high strength short fibers, but using short fibers with good dispersibility in part to give the role of stabilizing the above-mentioned coefficient of friction to the expected effect. Are obtained, and the present invention has been completed.

That is, the invention of this application is directed to a power transmission belt provided with a compressed rubber layer that is repeatedly compressed during belt running, wherein vinylon fiber and nylon fiber are mixed and dispersed as short reinforcing fibers in the compressed rubber layer. And above
The amount of the reinforcing short fibers in the compressed rubber layer is equal to that of rubber 1
15 to 30 parts by weight with respect to 00 parts by weight.
The amount of vinylon fiber in the rubber layer is
It is characterized in that it is 1 to 4 times the blending amount .

[0011] In the case of the present invention,
By giving the compressed rubber layer the role of ensuring the required elastic modulus, it is possible to eliminate the need to use a large amount of short fibers, while stabilizing the friction coefficient of the belt with the nylon fibers. Will be possible.

The amount of the reinforcing short fibers in the compressed rubber layer is preferably 15 to 30 parts by weight based on 100 parts by weight of the rubber.
It is preferred to use parts by weight. When the amount of short fibers is small,
This is because it is difficult to obtain a high elastic modulus in the compressed rubber layer even if high strength (or high elasticity) vinylon fibers are used, and if the amount of short fibers is too large, the dispersion in the rubber becomes difficult. Because it becomes.

With respect to the ratio of vinylon fibers and nylon fibers in the compressed rubber layer, it is preferable to increase the amount of vinylon fibers to the same amount or to increase the number of vinylon fibers without increasing the total amount of short fibers. From the viewpoint of heat resistance, it is preferable to increase the amount of vinylon fibers. On the other hand, if the proportion of the nylon fiber is too small, it is disadvantageous in terms of stabilizing the friction coefficient. Therefore,
Specifically, it is preferable that the blending amount of the vinylon fiber is 1 to 4 times the blending amount of the nylon fiber.

From the viewpoint of securing the elastic modulus of the compressed rubber layer with a small amount of short fibers, the elastic modulus of the vinylon fibers is preferably set to 160 to 240 g / de (denier).

It is preferable that the diameter of the nylon fiber is larger than the diameter of the vinylon fiber so that the end of the nylon fiber is prevented from falling down and comes into contact with the pulley without being covered with rubber.

Further, the above configuration is particularly effective when used for the compression rubber layer of a V-belt or a V-ribbed belt.

[0017]

As described above, according to the invention of this application, as the reinforcing short fibers mixed and dispersed in the compressed rubber layer,
Combined use of vinylon fiber and nylon fiber ,
The amount of the reinforcing short fibers in the compressed rubber layer was adjusted to rubber 1
15 to 30 parts by weight with respect to 00 parts by weight,
Since the amount of fiber is 1 to 4 times the amount of nylon fiber, the dynamic fatigue life of the power transmission belt is improved and the friction coefficient is stabilized without reducing workability (fiber dispersibility). In particular, the performance of a V-belt or a V-ribbed belt can be improved.

[0018] the modulus of elasticity of the vinylon fiber 160-24
The use of 0 g / de is more advantageous for securing the elastic modulus of the compressed rubber layer with a small amount of short fibers.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <Example of Structure of Transmission Belt> In a V-belt 1 as a transmission belt shown in FIG.
Is a tension member that is spirally wound so as to extend in the belt length direction and be arranged at a predetermined pitch in the belt width direction.
Is an adhesive rubber layer which is in close contact with the tensile member 2 and maintains its position properly;
Reference numeral 4 denotes a compressed rubber layer which is bonded to the inner peripheral side of the adhesive rubber layer 3 and is repeatedly compressed when the transmission belt 1 runs.
Reference numeral 6 denotes a rubberized canvas which covers the surface (inner peripheral surface) of the compressed rubber layer 4. Monofilaments 7, 8 extending in the belt width direction and contributing to the lateral pressure resistance and the like of the belt 1 are embedded in the adhesive rubber layer 3 on the outer peripheral side and the inner peripheral side of the tensile member 2, respectively. I have. The reinforcing short fibers 9 are embedded in the compressed rubber layer 4 so as to be oriented in the belt width direction.

<Relationship between Types and Compounding Amounts of Reinforcing Short Fibers and Belt Properties, etc.> The V belt 1 is prepared by changing the types and compounding amounts of the reinforcing short fibers to be mixed into the compressed rubber layer 4. Belt workability (rubber workability) and belt characteristics were evaluated. That is, as the reinforcing short fibers, one or two selected from nylon fibers (polyamide fibers), aramid fibers, general-purpose vinylon fibers and high-strength vinylon fibers were employed.

As the above-mentioned nylon fiber, 6,6 nylon manufactured by Asahi Kasei Corporation is used, and as the aramid fiber,
Connex (trade name of meta-aramid fiber) manufactured by Teijin Limited was used, and general-purpose vinylon fiber and high-strength vinylon fiber manufactured by Unitika Ltd. were used. Table 1 shows the strength and elastic modulus of each short fiber. Table 2 shows the composition of the reinforcing short fibers and the evaluation results.

[0022]

[Table 1]

[0023]

[Table 2]

Regarding the evaluation items in Table 2, the kneading processability is for evaluating the processability of rubber mixed with short fibers. The short fiber dispersibility is to evaluate the dispersibility of short fibers in rubber. The belt noise property is to evaluate whether or not noise is generated due to contact with a pulley when the belt is run. The belt friction coefficient evaluates the friction coefficient of the contact surface between the side surface of the belt and the pulley. The heat-resistant bending fatigue is to evaluate the bending fatigue due to heat based on the durability time when the belt is bent and driven by an idler at a high temperature.

For each of the above evaluations, a four-step evaluation system was adopted. That is, ◎ in the table is the best, ○
Indicates that the evaluation is one rank lower than the best but is good, Δ indicates that it is slightly defective, and X indicates that it is defective.

The section on viscoelasticity describes the results of preparing a rubber test piece in which short reinforcing fibers were mixed and dispersed, and measuring the dynamic elastic modulus E ′ at each of 25 ° C. and 100 ° C. This is for evaluating the elastic modulus of the compressed rubber layer. Short fiber meltability is
This is to evaluate whether the short fibers do not melt due to the moisture in the rubber when the compressed rubber layer is heated by the running of the belt due to the running of the belt. Those that were melted were designated as "melted" and those without melting were designated as "no melting".

According to Table 2, each of the examples in which the short fibers for reinforcement were nylon fibers alone, aramid fibers alone, general-purpose vinylon fibers alone and high-strength vinylon fibers alone had problems, but the high-strength vinylon fibers alone were problematic. In the case of the combination of the polyester fiber and the nylon fiber, generally good results were obtained.

More specifically, in the case of the nylon fiber alone, since the elastic modulus has a high temperature dependence, the evaluation of the heat-resistant bending fatigue resistance is low, and the dynamic elastic modulus is also 3%.
00 MPa was not obtained. In the case of the aramid fiber alone, the flexibility was poor due to poor rubber processability and short fiber dispersibility, and abnormal noise was also observed. In the case of the general-purpose vinylon fiber alone, the portion where the short fiber was hardened without dispersing was caused to be melted and turned into foreign matter to deteriorate the flexibility, and the noise was also generated. Also, this example:
The variation of the elastic modulus of the compressed rubber layer due to the melting of the short fibers was large. In the case of the high-strength vinylon fiber alone, a high elastic modulus was obtained with a small amount of short fiber, and the workability and dispersibility were good, but abnormal noise was generated. This is considered to be because the friction coefficient increased with the abrasion of the side surface of the compressed rubber layer.

On the other hand, in each of the examples in which the high-strength vinylon fiber and the nylon fiber were combined, the mixing ratio of both fibers was changed so that the dynamic elastic modulus at 25 ° C. became 300 MPa. However, the example in which the blending ratio of the high-strength vinylon fiber was increased showed better results. In the example in which the proportion of the nylon fiber is large, the temperature dependency of the elastic modulus is increased, so that the heat-resistant bending fatigue property is slightly deteriorated. From these results, it can be said that it is preferable that the blending ratio of the high-strength vinylon fiber and the nylon fiber be equal to each other or that the ratio of the high-strength vinylon fiber is larger.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a V-belt as an example of a transmission belt.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 V belt 2 Tensile body 3 Adhesive rubber layer 4 Compressed rubber layer 5,6 Rubberized canvas 7,8 Monofilament 9 Reinforcing short fiber

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-67351 (JP, A) JP-A-7-83287 (JP, A) JP-A-7-4470 (JP, A) JP-A-4- 366045 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16G 1/00-5/20

Claims (3)

(57) [Claims] To 1. A compression rubber layer which is repeatedly compressed during transmission belt travel, as reinforcing short fibers, and a vinylon fiber and nylon fiber are mixed dispersion, the amount of short fiber reinforcement in the compression rubber layer , Rubber
15 to 30 parts by weight with respect to 100 parts by weight, and the compounding amount of vinylon fiber in the compressed rubber layer is Nylon.
A power transmission belt characterized in that the amount is 1 to 4 times the blended amount of fiber . 2. The transmission belt according to claim 1, wherein the elasticity of the vinylon fiber is 160 to 240 g / de. 3. The power transmission belt according to claim 1, wherein the power transmission belt is a V-belt.