JPH07127689A - Toothed belt - Google Patents

Abstract

PURPOSE:To provide a toothed belt which has a straightforward running ability so that the belt can be inhibited from making contact with a flange piece of a pulley in order to enhance the accuracy of post-processing such as polishing or the like of the belt side surface, and to decrease unevenness in the tensile strength thereof. CONSTITUTION:A toothed belt is composed of a belt body on which several tooth parts 2 are longitudinally laid at predetermined intervals, and a rear part 4 in which core wires 3 are longitudinally embedded. An even number of cords in pairs each having a structure the same as that of the core wires 4 embedded in the rear part 4 but a twisting direction of which is reverse to that of the core wires 4 are laid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt, and more specifically, it has a straight running property of the belt, and by this, post-processing such as polishing of the side surface of the belt is accurately performed, and variations in tensile strength are caused. Regarding a reduced toothed belt.

[0002]

2. Description of the Related Art In a conventional toothed belt, two types of cords of S twist and Z twist are alternately used as a core wire in order to ensure straight running performance during use operation. Then, the side surface of the toothed belt obtained by cutting from the belt sleeve was ground by a grinder to remove the fray and fluff of the cord exposed on the side surface. This is because when aramid fiber is used as the core wire, the cut core wire is exposed on the side surface of the belt, and when the belt is run, the exposed core wire is frayed or fuzzed.

Further, since the aramid fibers have extremely weak binding force in the diametrical direction of the monofilaments, the fibers tend to be fibrillated or divided, and even if the core wire is embedded in rubber, the fibers are hardened. Even if it is adhered to, the cut belt side surface contacts both sides of the pulley, and if the idler pulley is repeatedly contacted, the end of the core wire is frayed, the aramid fiber is split and the core wire is one after the other in the rubber. This was also due to damage to the belt that was pulled out and wrapped around the rotating shaft, or to a mechanical failure.

[0004]

However, in the conventional toothed belt, since the belt sleeve is cut into a predetermined width, the twisting and returning force of each cord is generated depending on the number of core wires contained therein, and the cord tends to be biased to one side. there were. When this toothed belt is run, it abuts against the flange piece of the pulley, and when the side surface of the toothed belt is ground by a grinder, one side surface is polished a lot and the width of the belt is disturbed. A large variation occurred in the tensile strength of the attached belt. The present invention solves each of the drawbacks as described above, and by having the straight running property of the belt, the contact with the pulley flange piece is prevented and the accuracy of post-processing such as polishing of the side surface of the belt is improved. An object of the present invention is to provide a toothed belt with reduced variations in tensile strength.

[0005]

That is, a toothed belt, which is a feature of the present invention, has a belt main body having a plurality of tooth portions arranged at a constant pitch in the longitudinal direction of the belt and a core wire along the same direction. In a toothed belt including an embedded back portion, the cords have the same configuration as the core wire embedded in the back portion, and an even number of pairs of cords having opposite twist directions are arranged.

The toothed belt of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a cross-sectional perspective view of essential parts of a toothed belt according to the present invention. The toothed belt 1 has a plurality of tooth portions 2 along the longitudinal direction of the belt, and a back portion in which an even number of core wires 3 having a same rope structure and a pair of cords having an upper twist direction of S twist and Z twist are arranged and embedded. 4 and the tooth cloth 5 covering the surfaces of the tooth portion 6 and the tooth bottom portion 7.

The rubber used for the tooth portion 2 and the back portion 4 is heat aging resistance such as hydrogenated nitrile rubber, chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene (ACSM) and chloroprene rubber. Of improved rubber are preferred. The hydrogenated nitrile rubber has a hydrogenation rate of 80% or more, preferably 90% or more in order to exhibit heat resistance and ozone resistance. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% has extremely low heat resistance and ozone resistance. Carbon black, zinc white, stearic acid, a plasticizer, an antioxidant, etc. are added as a compounding agent in the rubber, and sulfur and an organic peroxide are used as a vulcanizing agent. The vulcanizing agent is not particularly limited.

The canvas used as the tooth cloth 5 is 6 nylon, 66 nylon, polyester, aramid fiber or the like, and may be used alone or in a mixture. Warp threads (belt width direction) and weft threads (belt length direction) of the tooth cloth 5
The composition is a filament yarn or spun yarn of the above fiber, and the woven structure may be any of a plain woven fabric, a twill woven fabric and a satin woven fabric. In addition, it is preferable to partially use stretchable urethane elastic yarn as the weft yarn.

Among them, in the case of a plain weave canvas, since wefts and warps are alternately cross-laminated vertically, the corrugated intersections of the wefts and warps are formed continuously in the weft and warp directions. on the other hand,
When twill or satin weave is used, wefts and warps form multiple wavy intersections each, and there are fewer wavy intersections than normal plain weave, and the rubber extends not only between yarns but also between intersections. It is preferable that it sufficiently penetrates, and when this is used for the belt corrugated portion, direct contact between the warp yarns and the weft yarns in the belt flexibility can be avoided, and the belt life can be improved.

The tooth cloth 5 is treated with an RFL solution, an isocyanate solution or an epoxy solution. RFL
The liquid is a mixture of latex with an initial condensate of resorcin and formalin, and the latex used here is styrene. butadiene. It is a latex of vinyl pyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin and the like.

The core wire 3 is made by twisting filaments of E glass or high-strength glass having a diameter of 5 to 9 μm and treated with an RFL liquid or the like which is a protective agent or adhesive composed of a rubber compound. . With glass fiber cord, treated strands 10-15 times / 1
After twisting the twisted rope with 0 cm of twist number to make a child rope, after at least 2 or more, preferably 2 to 4 of these child ropes are aligned,
It is twisted 6 to 9 times per 10 cm. Core 3
Have exactly the same cord configuration (strand diameter, number of lower twists, number of upper twists), and at least a pair of cords having opposite twist directions are prepared. Of course, in the pair of cords, the twisting directions of the upper twist and the lower twist may be opposite to each other, or the twisting directions of only the lower twist may be opposite to each other.

In the aramid fiber cord used as the core wire 3, 100 to 100 denier filaments are used.
A total of 3000 to 3100 denier raw yarns of which 3000 yarns are converged are previously subjected to an adhesion treatment with a treatment liquid selected from an epoxy compound and an isocyanate compound. This enhances the focusing property of the filament group and improves the fraying property. Further, since the obtained filament group is hard and ribbon-shaped, when the normal twisting is performed, the twist becomes non-uniform, the strength of the twisted yarn cord is reduced, and the bending fatigue is deteriorated. Subsequently, the twisted yarn is subjected to RFL treatment and then overcoated with rubber paste or treated with only rubber paste. If necessary, the adhesive treatment with the rubber paste may be repeated several times.

The aramid fiber used for the core wire 3 is an aramid having an aromatic ring in the main chain of the molecular structure, such as Conex, Nomex, Kevlar, Technora, Twaron and the like. The above-mentioned yarn is twisted at a twist number of 0 to 15 times / 10 cm to form a child rope, and at least 2 pieces of this child rope are used.
After arranging more than one, preferably two to three, 10 to 20
It is twisted with a twist number of 10 cm per turn. The core wires 3 have exactly the same cord configuration (strand diameter, number of lower twists, number of upper twists), and a pair of cords in which the directions of the lower twist and the upper twist are opposite to each other are prepared. Of course, in the pair of cords, the twisting directions of the upper twist and the lower twist may be opposite to each other, or the twisting directions of only the lower twist may be opposite to each other. Further, in the present invention, carbon fiber, polyelter fiber, metal fiber or the like can be used as the core wire 3.

The number of the core wires 3 is an even number as the core wires buried in the back. In the case of the present invention, one side surface of the belt has two areas where the cord is cut and exposed in the longitudinal direction of the belt, and the other side surface also has two areas. In the present invention, when only the cords that are cut and exposed and the buried cords are removed are counted, a pair of cords having opposite twisting directions are arranged in an even number in all regions. The reason why the cords thus cut and exposed are not counted is that the cords that are cut and exposed in the longitudinal direction of the belt have the untwisting force of the cord released and do not carry the belt tensile strength. If the number of core wires 3 is an odd number, the twisting back force of each cord is biased to one side, and straight running performance cannot be maintained.

[0015]

In the toothed belt of the present invention, the cords having the same cord construction as the core wire buried in the back portion and the even number of a pair of cords in which the directions of the upper twists are opposite to each other are arranged. As a result, the twisting and returning forces of the cords are offset to each other, so that straight running performance can be achieved. The belt does not come into contact with the flange during traveling, and post-processing such as polishing of the side surface of the belt can be performed accurately. Further, since each core wire in the belt width direction receives an averaged force, stress concentration on the core wire is eliminated, and variations in the tensile strength of the belt are reduced.

[0016]

EXAMPLES The present invention will be described in detail below with reference to examples. Examples 1 and 2 and Comparative Examples 1 and 2 Weft yarns made of 140 denier 66 nylon and 280 denier 66 nylon and 140 denier urethane elastic yarns, with a warp density of 180 (pieces / 5 cm) and a weft density of 160 ( After weaving with a twill cloth (book / 5cm),
The woven fabric was vibrated in water to shrink it to about ½ of the width at the time of weaving, and then the canvas was dipped in rubber paste and dried to obtain a tooth cloth.

Next, as a core wire, a non-twisted multifilament strand in which a predetermined number of aramid fiber filaments having a wire diameter of 1.5 denier are aligned and formed, is dipped in an adhesive made of an epoxy solution and dried. After that, two of these strands were collected and twisted at a twist number of 15 times / 10 cm to produce a pair of S and Z twisted cords. The composition of the obtained cord is 1500 ^D / 2.

The above-mentioned tooth cloth was finished into an endless tubular body, which was set in a mold. From above, a pair of S and Z cords are alternately wound with a core pitch of 1.0 mm and a tension of 10 kg / piece, and a rolled sheet of hydrogenated nitrile rubber compound is wound around the cord and vulcanized by a normal press-in vulcanization method. After vulcanization, the vulcanized sleeve was cut into a predetermined width to produce individual belts. Belt size is 10 teeth
5, tooth pitch: 8 mm, and the tooth profile of the belt was STPD. Each of the obtained belts is cut and measured as the number of core wires, and the belt is hung on a driving pulley (21 teeth) having a flange and a driven pulley (42 teeth) to obtain an ambient temperature at room temperature. Drive pulley rotation speed of 7,200 rp
m, driven pulley 12 load 5 ps, belt initial tension 15 k
After being run for 200 hours, the abrasion rate (weight change rate) on the side surface of the belt, variation in the tensile strength of the belt, and the tensile strength of the belt were measured. The results are shown in Table 1.
The variations in the tensile strength of the belt and the tensile strength of the belt are obtained from 20 belts.

[0019]

[Table 1]

From these results, the belt in which an even number of a pair of S-twisted and Z-twisted cords are arranged as the core wire has a smaller wear rate on the side surface of the belt than that of the odd-numbered one, and thus is excellent in straight running property and pulled. It can be seen that the variation in strength is also small.

[0021]

As described above, according to the present invention, the cords having the same structure as the core wire embedded in the back portion and the even number of the pair of cords having the opposite twisting directions are arranged. It is excellent in running property and does not come into contact with the flange during running, and post-processing such as polishing of the side surface of the belt can be performed accurately. Moreover, since each core wire in the belt width direction receives an averaged force, stress concentration on the core wire is eliminated, and variations in the tensile strength of the belt are reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a toothed belt according to the present invention.

[Explanation of symbols]

 1 Toothed belt 2 Teeth 3 Core wire 4 Back

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Matsushita 4-1-21, Hamazoe-dori, Nagata-ku, Kobe Mitsuboshi Belt Co., Ltd.

Claims (1)

[Claims] 1. A toothed belt comprising a belt main body in which a plurality of tooth portions are arranged at a constant pitch in the longitudinal direction of the belt and a back portion in which core wires are embedded along the same direction, and a core wire embedded in the back portion. A toothed belt having the same cord configuration and having an even number of a pair of cords having opposite twisting directions.