JPH11336847A - Tension body for transmission belt and transmission belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance bending fatigue strength for a transmission belt. SOLUTION: This tension body 2 can be obtained by bundling poly-para- phenylene benzobisoxazole fiber bundles in 700 to 2300 de in one direction, with a twisting factor in a range specified as follows; K=T×D<1/2> ×1/287, wherein 0.5<=K<=2.5, K is a twisting factor; T is the number of twisting; (t/10 cm), and D is Denier number}. The transmission belt 1 is made out of the tension body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt tensile member embedded in various belts such as a toothed belt, a V-belt, a flat belt, a speed change belt, and a power transmission belt using the same.

[0002]

2. Description of the Related Art Conventionally, a glass fiber cord is generally used as a tension member for a belt. For example, an EC is used for a timing belt for driving an overhead cam (OHC) for an automobile.
A cord with a G150-3 / 13 or 3/11 configuration is used as the tensile body. However, a belt using the cord as a tensile member has poor flex fatigue, and the belt strength is significantly reduced particularly in the presence of moisture such as moisture. Therefore, there is a concern that the timing belt may be broken while the vehicle is running. On the other hand, it has been proposed to use a cord made of polyparaphenylene terephthalamide fiber, which is an organic fiber, and a fiber having a similar structure (hereinafter, referred to as “amilad fiber”) for the tensile member instead of the glass fiber. (Japanese Unexamined Patent Publication No.
4-9347, Hira 23856). However,
Even with the use of the above tensile members, the fatigue resistance is not sufficient under the increasingly strict belt usage conditions such as high temperature, high tension, multi-bending, and small pulleys in recent years.

In recent years, polyparaphenylene benzobisoxazole fibers (hereinafter, referred to as PBO fibers) having about twice the strength of aramid fibers have been developed and are expected to be used as tensile members for belts.

[0004]

However, due to the inherent rigidity of the PBO fiber, when used in a structure and a structure conventionally used for aramid fibers, excessive strain is applied to the filament, As a result, only fatigue resistance equal to or lower than that of aramid fiber can be obtained.

[0005] Therefore, the present invention is to make the most of its properties when using PBO fiber as a tensile member for a belt.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on such problems and have found that PBO fibers are polyester fibers conventionally used as belt tensile members.
With a configuration that is less than that used for organic fibers such as aramid fibers, the number of twists is reduced, and if a single twist yarn is used, no burden is applied to the fiber filament, and as a result, sufficient fatigue resistance is exhibited. The present invention has been completed.

More specifically, in order to use the PBO fiber as a tension member for a belt, the PBO fiber is formed by bundling the PBO fiber.
It is characterized in that a fiber bundle of 0 to 2300 de is twisted in one direction with a twist coefficient in a range defined by the formula.

K = T · D ^1/2 · 1/287... 0.5 ≦ K ≦ 2.5 (K: twist coefficient T: twist number (t / 10 cm) D: fiber denier number) The reason for this is that if it is less than this, the strength per belt width cannot be obtained. This is because the strain of the surface layer increases, and sufficient fatigue resistance cannot be obtained.

The reason why the twist coefficient is set to 0.5 or more is that if the twist coefficient is lower than that, the filaments are poorly aligned, a predetermined strength cannot be obtained, and the cord is not structurally stable. The reason why the twist coefficient is set to 2.5 or less is that if the twist coefficient is larger than this, the strain applied to the filament inside the cord increases, and the filament is easily broken.

Further, the reinforcing member (tensile member for belt) produced as described above is used in a stage before being embedded in the rubber layer.
For example, epoxy resin, isocyanate compound, ethylene urea compound, resorcinol-formalin latex (R
An adhesive treatment such as FL) or a stretching treatment can be performed. As the bonding method, a dipping method is preferable because it is necessary to uniformly adhere the adhesive to the reinforcing member.

[0011]

As described above, according to the present invention,
Since the PBO fiber is a fiber bundle of 700 to 2300 de and twisted in one direction with a twist coefficient in a range specified by the formula, a belt tensile member having excellent fatigue resistance can be obtained. Bending fatigue can be improved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

A transmission belt 1 shown in FIG. 1 is a toothed belt. In the figure, reference numeral 2 denotes a tension member extending in the belt length direction, 3 denotes a backing rubber provided on the back side of the tension member 2, 4 Reference numeral 5 denotes tooth rubber provided on the inner surface side of the tension member 2 and constituting teeth of the toothed belt. Reference numeral 5 denotes a tooth cloth which covers the toothed side of the toothed belt.
The tensile member 2 is made of a bundle of PBO fibers 700 de.
A fiber bundle of ２2300 de is twisted in one direction with a twist coefficient in the range specified by the formula.

K = T · D ^1/2 · 1/287... 0.5 ≦ K ≦ 2.5 (K: twist coefficient T: twist number (t / 10 cm) D: fiber denier number) (Example 1) PBO fiber (Product name manufactured by Toyobo Co., Ltd.) 10
A 00de yarn is twisted in one direction 5 times / 10 cm, and then immersed in an isocyanate compound adhesive to form a sub-coat layer, and then to a resorcinol formalin latex (RFL) adhesive. It was immersed to form a second coat layer, and then heat-treated under tension to obtain a tensile member for a belt. In the same manner, a belt tensile body which was twisted in the opposite direction to the above direction and subjected to an adhesive treatment was also prepared.

Then, a toothed belt 1 shown in FIG. 1 was produced using the obtained belt tensile member. As the tooth cloth 5,
Use 6,6 nylon yarn for the yarn extending in the belt width direction,
Wooly processing of industrial 6,6 nylon was used for the yarn extending in the belt longitudinal direction. Further, as the back rubber 3 and the tooth rubber 4, a rubber composition containing chloroprene rubber as a main raw material was used.

The toothed belt 1 was formed from the above-mentioned materials by a normal press-fitting method. The tooth pitch is 8mm STS tooth type, the number of teeth is 113, belt width is 19mm
It is.

Example 2 A toothed belt was prepared in the same manner as in Example 1 except that the yarn of 1000 de of PBO fiber was twisted 20 times / 10 cm in a single twist.

(Example 3) In Example 1, two yarns of 1000 de of PBO fiber were collected and totaled 2000 d.
e, and a toothed belt was prepared in the same manner as in Example 1 except that the number of twists was 4 times / 10 cm.

(Example 4) In Example 1, two yarns of 1000 de of PBO fiber were collected and totaled 2000 d.
e, and a toothed belt was prepared in the same manner as in Example 1, except that the number of twists was 16 times / 10 cm.

Example 5 A toothed belt was produced in the same manner as in Example 1, except that the 1500-bore yarn of PBO fiber was twisted 8 times / 10 cm.

(Comparative Example 1) In Example 1, three 1500 de yarns of PBO fiber were collected and total 4500 d.
e, and a toothed belt was prepared in the same manner as in Example 1, except that the number of twists was 12 times / 10 cm.

(Comparative Example 2) Five yarns of 500 de of PBO fiber in Example 1 were collected and total 2500 de.
A toothed belt was prepared in the same manner as in Example 1, except that the number of twists was 6 times / 10 cm.

(Comparative Example 3) In Example 1, two yarns of 1000 de of PBO fiber were collected and totaled 2000 d.
e, and a toothed belt was prepared in the same manner as in Example 1, except that the number of twists was 20 times / 10 cm.

(Comparative Example 4) In Example 1, the tensile body was Kepler 119 (trade name, manufactured by DuPont) at 1500 de.
A toothed belt was prepared in the same manner as in Example 1 except that three yarns were collected to make a total of 4500 de, and the number of twists was set to 12 times / 10 cm.

Table 1 summarizes the structures of the examples and comparative examples.

[0026]

[Table 1]

<Water injection flex fatigue test> Belt A with test teeth
Is wound around four large pulleys 31 constituting the belt bending tester shown in FIG. 2 and four small pulleys 32 (diameter 30 mm) arranged between the adjacent large pulleys 31, and the weight 3
In 3, the belt was run at 5500 rpm with a load of 80 kgf applied to the test toothed belt A. Number of bending 1 × 10
After ⁸ times, the residual strength of the belt after 5 × 10 ⁸ times was calculated to evaluate the fatigue property. Table 2 shows the results.

[0028]

[Table 2]

As is evident from the test data in Table 2, the example was superior to the comparative example in the belt strength retention rate.

Although the above embodiment relates to a toothed belt, the present invention is not limited to this, and it is needless to say that the present invention can be applied to a transmission belt such as a V belt, a flat belt and a V-ribbed belt.

[Brief description of the drawings]

FIG. 1 is a sectional view of a toothed belt.

FIG. 2 is a schematic configuration diagram of a belt bending fatigue tester.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Tensile body 3 Back rubber 4 Tooth rubber 5 Tooth cloth

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Sakanaka 3-2-1-15 Meiwadori, Hyogo-ku, Kobe-shi, Hyogo Inside BANDO CHEMICAL CO., LTD. (72) Kenichi Fukunaga 3 Meiwa-dori, Hyogo-ku, Kobe-shi, Hyogo No.2-15, Bando Chemical Co., Ltd.

Claims (2)

[Claims] 1. A tensile member for a power transmission belt, wherein a fiber bundle of 700 to 2300 de obtained by bundling polyparaphenylene benzobisoxazole fibers is twisted in one direction with a twist coefficient in a range specified by a formula. . K = T · D ^1/2 · 1/287... 0.5 ≦ K ≦ 2.5 (K: twisting factor T: twisting number (t / 10 cm) D: fiber denier number) 2. A power transmission belt comprising the belt tensile body according to claim 1.