JPH1163115A - Transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of an abnormal sound caused by a very little speed change in a belt by reducing a friction coefficient between a canvas layer back face and a back pulley even if a surface smooth inexpensive back pulley is used when the back pulley is arranged on the back face side of a V ribbed belt. SOLUTION: A canvas layer 7 impregnated with sizing rubber in which carbon short fiber is mixed, is formed on a back face of upper rubber 1 of a belt main body 6. A fiber length of the carbon short fiber is set to 5 to 500 μm, and the fiber cross-sectional area is set to 3 to 20 μm<2> . The weight ratio of the carbon short fiber to the sizing rubber is set to 1 to 50%.

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 such as a V-belt, a V-ribbed belt or a flat belt, and more particularly to a technical field in which a back pulley is provided on the back side of the belt.

[0002]

2. Description of the Related Art Conventionally, in a transmission belt wound around a driving and driven pulley, an idler pulley is provided from the back side of the belt in order to maintain the tension of the belt and to increase the length of winding around the driving pulley. It is well known to push a rear pulley such as a tensioner pulley. In recent years, it has been known in automobiles and the like that an engine accessory such as a generator, a cooling fan, or an oil pump is operated by using a driving force from a rear pulley disposed on the rear side of the belt.

[0003]

However, when the back pulley is provided on the back side of the belt as described above, a slip occurs between the back pulley and the back of the belt, and the canvas provided to suppress the wear on the back of the belt. Impregnated rubber (glue rubber) exposed on the back side of the layer and bonding the canvas layer to the belt body
Sticks to the back pulley. As a result, there is a problem that a step is formed on the surface of the rear pulley by the adhesive, and the step causes the belt to vibrate and generate abnormal noise.

Therefore, it is conceivable to suppress the adhesion of the adhesive rubber to the rear pulley by blending a large amount of carbon black into the adhesive rubber of the canvas layer. However, depending on the use conditions, the rubber does not adhere to the rear pulley. Also, abnormal noise may occur. That is, when a minute speed fluctuation occurs in the belt due to the angular speed fluctuation of the driving pulley, a minute slip occurs between the belt and the back pulley having inertia due to the speed fluctuation of the belt. At this time, if the friction coefficient between the back of the belt (the back of the canvas layer) and the back pulley is large, smooth sliding does not occur between the belt and the belt, and vibration is generated in the belt. Sound) is generated.

For this reason, it is conceivable to reduce the coefficient of friction between the back of the canvas layer and the back pulley by changing the material of the back pulley and the plating of the surface of the back pulley to roughen the surface of the back pulley. Then, there is a problem that the cost of the rear pulley increases. Further, in the method of roughening the surface of the rear pulley by plating, there is a problem that the plating is easily peeled at an early stage of use, and rust is generated on the rear pulley.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a rear pulley on the rear side of a transmission belt by devising the belt. Even if an inexpensive back pulley having a smooth surface is used, the friction coefficient between the back of the canvas layer and the back pulley is reduced to prevent the generation of abnormal noise due to a minute speed fluctuation of the belt.

[0007]

In order to achieve the above object, according to the present invention, short carbon fibers are mixed into the glue rubber of the canvas layer.

More specifically, according to the first aspect of the present invention, the transmission belt has a canvas layer impregnated with glue rubber mixed with short carbon fibers on the back surface of the belt body.

By mixing carbon short fibers into the glue rubber of the canvas layer, the back surface of the canvas layer becomes rough and the friction coefficient of the glue rubber itself becomes small, so that the contact surface with the back surface of the canvas layer is smooth. Even if an inexpensive back pulley is used, the coefficient of friction between the back of the canvas layer and the back pulley will be small. As a result, even if a slight speed fluctuation occurs due to the angular speed fluctuation of the driving pulley on the belt, the slip between the back side of the canvas layer and the rear pulley is smoothly performed. Does not need to be changed so as to be coarse. Therefore, it is possible to prevent the generation of abnormal noise due to the minute speed fluctuation of the belt at low cost.

According to a second aspect of the present invention, in the first aspect of the present invention, the short carbon fiber has a fiber length of 5 to 500 μm and a fiber cross-sectional area of 3 to ²⁰ μm ² .

That is, the fiber length of the short carbon fiber is 5 μm.
If the fiber cross section is smaller than m and the fiber cross-sectional area is larger than 20 μm ² , the short carbon fibers are likely to fall off from the back of the canvas layer, and the effect of preventing abnormal noise cannot be maintained. If the fiber length is larger than 500 μm and the fiber cross-sectional area is smaller than 3 μm ^{2, the} carbon short fibers are not uniformly dispersed in the glue rubber due to the entanglement of the carbon short fibers, and the running life of the belt is reduced. The cross-sectional areas are 5 to 500 μm and 3 to ²⁰ μm ² , respectively. Therefore, while maintaining the running life of the belt, it is possible to prevent the generation of abnormal noise due to the minute speed fluctuation of the belt for a long time.

According to a third aspect of the present invention, in the first or second aspect, the weight ratio of the short carbon fiber to the glue rubber is 1 to 50%.

That is, if the weight ratio of the short carbon fiber to the glue rubber is less than 1%, it is not possible to effectively prevent the generation of abnormal noise, but if it is more than 50%,
Since the running life of the belt is reduced, it is set to 1 to 50%. Therefore, it is possible to more effectively prevent the generation of abnormal noise due to the minute speed fluctuation of the belt while maintaining the running life of the belt.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a V-ribbed belt B as a transmission belt according to an embodiment of the present invention. This belt B is wound around a driving and driven pulley,
A rear pulley is provided on the rear side, and is configured to perform a task different from that of the driven pulley by taking a driving force from the rear pulley.

An upper rubber 1 is provided on the back side of the belt B.
However, a bottom rubber 2 is provided on the inner surface side of the belt. A plurality of cores 4 extending between the rubbers 1 and 2 in the longitudinal direction of the belt and fixed by an adhesive rubber 3.
4, ... are provided. On the inner surface of the belt of the bottom rubber 2, two V-shaped grooves 5 are formed continuously in the longitudinal direction of the belt. The upper rubber 1, the bottom rubber 2, the adhesive rubber 3, and each core 4 constitute a belt body 6, and the back surface of the belt body 6, that is, the belt back surface of the upper rubber 1 is covered with a canvas layer 7. .

The canvas layer 7 is composed of a single layer or a plurality of layers of canvas.
Glue rubber for bonding to the upper rubber 1 is impregnated, and the glue rubber is exposed on the back surface of the canvas layer 7 to completely cover the canvas of the canvas layer 7. The glue rubber has a fiber length of 5-500μ
m, and a short carbon fiber having a fiber cross-sectional area of 3 to ²⁰ μm ² is mixed therein, and the weight ratio of the short carbon fiber to the glue rubber is set to 1 to 50%.

That is, the fiber length of the short carbon fiber is 5 μm.
If it is smaller than m and the fiber cross-sectional area is larger than 20 μm ² , the short carbon fibers are likely to fall off from the back of the canvas layer 7, and the effect of preventing the generation of abnormal noise due to the minute speed fluctuation of the belt B is maintained. On the other hand, if the fiber length of the short carbon fiber is larger than 500 μm and the cross-sectional area of the short fiber is smaller than 3 μm ² , the short carbon fibers are not uniformly dispersed in the glue rubber due to the entanglement of the short carbon fibers. Since the running life of B is reduced, the fiber length and the fiber cross-sectional area are 5 to 500 μm and 3 to 20 μm, respectively.
μm ² . If the weight ratio of the short carbon fiber to the glue rubber is less than 1%, the effect of preventing abnormal noise is insufficient, but if it is more than 50%, the running life of the belt B is shortened. , 1 to 50%.

When the V-ribbed belt B having the above configuration is driven by driving a driving pulley, when a slight speed fluctuation occurs in the belt B due to an angular speed fluctuation of the driving pulley, the belt B is driven by the speed fluctuation of the belt B. A slight slip occurs between the motor and the rear pulley having inertia.
At this time, if the coefficient of friction between the rear surface of the canvas layer 7 and the rear pulley is large, smooth sliding does not occur between them, and vibration is generated in the belt B, and this vibration is transmitted to the rear pulley, and a high level difference between a key and a key is generated. Sound may be generated. However, in this embodiment, since carbon short fibers are mixed in the glue rubber of the canvas layer 7, the back surface of the canvas layer 7 is relatively rough, and the friction coefficient of the glue rubber itself is relatively small. Therefore, even if an inexpensive rear pulley having a smooth contact surface with the rear of the canvas layer 7 is used, the coefficient of friction between the rear of the canvas layer 7 and the rear pulley is relatively small. As a result, the belt B
Even if a slight speed fluctuation occurs, since the slip between the back of the canvas layer 7 and the back pulley is performed smoothly,
It is not necessary to change the material of the rear pulley or the plating on the surface of the rear pulley so that the surface of the rear pulley becomes rough. Therefore,
It is possible to prevent the generation of abnormal noise due to the minute speed fluctuation of the belt B at low cost.

The short carbon fiber has a fiber length of 5 to 50.
0 μm, the fiber cross-sectional area is 3 to ²⁰ μm ² , and the weight ratio of the short carbon fiber to the glue rubber is set to 1 to 50%. Generation of abnormal noise can be stably and effectively prevented over a long period of time.

Further, since the glue rubber is exposed on the back surface of the canvas layer 7 and completely covers the canvas of the canvas layer 7, a lot mark or the like indicating the production lot of the belt B is easily displayed on the back surface of the belt B. Can be.

In the above embodiment, the example of the V-ribbed belt is shown as the transmission belt, but the present invention is not limited to this, and the present invention can be applied to a transmission belt such as a V-belt or a flat belt. .

[0022]

Next, a specific embodiment will be described. First, V-ribbed belts were prepared by setting the components of the glue rubber and the blending amounts of the short carbon fibers as shown in “Examples” in Table 1. At this time, the number of V-shaped cross-section grooves on the inner surface of the belt of the bottom rubber was two (the number of ribs was three).

For comparison, the same V as in the above embodiment was used.
A ribbed belt was produced (Comparative Example). No carbon short fibers were mixed in the V-belt of this comparative example, and instead, a large amount of carbon black was blended to suppress adhesion of the glue rubber to the back pulley.

[0024]

[Table 1]

As shown in FIG. 2, the back pulley 1 in each of the V-ribbed belts 11 of the above embodiment and the comparative example.
The coefficient of back friction for 2 was measured. That is, each belt 11 is cut, and a weight 13 (weight DW) and a load cell 14 are connected to both ends of the cut, respectively.
The intermediate portion of each belt 11 has a back pulley 12 on the back side of the belt.
And wound around the rear pulley 12 which is rotationally fixed so as to come into contact therewith, so that the winding angle becomes a right angle.

Subsequently, as shown in FIG. 3, a test was conducted to check the running sound of each V-ribbed belt 11. That is, each belt 11 includes a driving pulley 16, a rotatable idler pulley 17 disposed above the driving pulley 16, and a rotatable idler pulley 18 disposed beside the driving pulley 16 and the idler pulley 17. The rotatable rear pulley 12 is disposed between the drive pulley 16 and the idler pulley 18. The drive pulley 16 was rotated at 1000 rpm while a weight DW (40 kgf) was applied upward to the idler pulley 17. At this time, while listening to and comparing the running noise of each V-belt 11,
Microphone 1 arranged 35 mm apart from each belt 11 in the horizontal direction at the periphery of drive pulley 16 of back pulley 12
The noise was measured according to No. 9 and frequency analysis was performed. The drive pulley 16 and the idler pulleys 17 and 18 each had a pulley diameter of 100 mm, and the rear pulley 12 had a pulley diameter of 85 mm. Each of the above measurements was performed at room temperature.

Table 1 shows the results of the measurement of the back friction coefficient and the result of hearing the running sound, and FIG. 4 shows the results of frequency analysis. From this, it can be seen that the coefficient of friction on the back side of the belt of the example is about 0.1 lower than that of the belt of the comparative example. In the belt of the comparative example, a loud squeak sound was generated. On the other hand, the belt of the example was good without any such noise. This difference is also evident from FIG. 4, in which the belt of the comparative example has a large peak at a high frequency which is not seen in the belt of the example. Therefore, by mixing the carbon short fibers into the glue rubber, the friction coefficient between the canvas layer rear surface and the rear pulley can be reduced. It can be seen that generation of abnormal noise due to speed fluctuation can be suppressed.

[0028]

As described above, according to the first aspect of the present invention, the transmission belt has a canvas layer impregnated with glue rubber mixed with short carbon fibers on the back surface of the belt body. In addition, it is possible to prevent the generation of abnormal noise due to the minute speed fluctuation of the belt at low cost.

According to the second aspect of the invention, the short carbon fiber has a fiber length of 5 to 500 μm and a fiber cross-sectional area of 3 to 500 μm.
By setting the thickness to 20 μm ² , the effect of preventing abnormal noise generation can be maintained for a long period of time while maintaining the running life of the belt.

According to the third aspect of the invention, by setting the weight ratio of the short carbon fiber to the glue rubber to 1 to 50%, the running life of the belt is maintained and the generation of abnormal noise is more effectively prevented. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a V-ribbed belt as a transmission belt according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a procedure for measuring a rear friction coefficient of a V-ribbed belt with respect to a rear pulley.

FIG. 3 is a schematic view showing a procedure of a test for examining a running sound of a V-ribbed belt.

FIG. 4 is a graph showing a frequency analysis result.

[Explanation of symbols]

 B V-ribbed belt (transmission belt) 6 Belt body 7 Canvas layer

Claims (3)

[Claims] 1. A power transmission belt having a canvas layer impregnated with a glue rubber mixed with short carbon fibers on a back surface of a belt body. 2. The transmission belt according to claim 1, wherein the short carbon fiber has a fiber length of 5 to 500 μm and a fiber cross-sectional area of 3 to ²⁰ μm ² . 3. The transmission belt according to claim 1, wherein the weight ratio of the short carbon fiber to the adhesive rubber is 1 to 50%.