JPH0953688A - Toothed belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toothed belt maintained to an objective PLD by changing thickness of a tooth cloth with belt tension, to decrease a change amount of the PLD by suppressing wearing of the tooth cloth even after belt running, to improve flexing fatigue resistance of the belt, and extend a running life. SOLUTION: A toothed belt 1 comprises a plurality of tooth parts 2 arranged along a lengthwise direction, back part 4 burying a core wire and a tooth cloth 5 coating a surface of the tooth part and a surface of a tooth bottom part. In this constitution, at least one of a warp arranged in a belt width direction and a weft arranged in a belt lengthwise direction, in the tooth cloth 5, contains a spun yarn 10 to 60wt.% total fiber weight, in the case of no receiving tension by the belt, a PLD of the belt is set to a value 5 to 30% larger than a preset value of the PLD used when set a meshed pulley external diameter, and in the case of receiving tension by the belt meshed with a pulley, the PLD of the belt is decreased.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a toothed belt,
The present invention relates to a toothed belt having good bending fatigue resistance and extending running life.

[0002]

2. Description of the Related Art Tooth pitch is 8.0 mm or 9.525 m
The toothed belt of m is mainly used for driving an overhead camshaft of an automobile. As the engine output increases and the engine room becomes more compact due to technological advances in recent years, the load and tension on the belt are increasing, and the ambient temperature when the belt is running is also increasing. There is a demand for a high-quality toothed belt satisfying the quietness in addition to such bending resistance, heat resistance, and tooth chipping resistance.

Therefore, as one of the countermeasures, a method of improving the constituent material of the toothed belt is being aimed at. For example, for the rubber of the teeth and back, hydrogenated nitrile rubber (H-NBR) or chlorosulfonated polyethylene (CSM) is used instead of conventional chloroprene, and the core wire also has high strength compared to conventional E glass. Transition to glass and aramid fiber. For example, a toothed belt using a hydrogenated nitrile rubber and a core wire of K glass is, for example, an actual flat belt 1-111848.
The toothed belt disclosed in Japanese Patent Laid-Open Publication No. 5-215 is disclosed in Japanese Patent Application Laid-Open No. 5-215, which uses a core of hydrogenated nitrile rubber and aramid fiber.
No. 186 is disclosed.

Further, as a material for a tooth cloth, which has an easy adhesive property with a rubber tooth and withstands a stress received from a pulley, a conventional multifilament crimped yarn of polyamide fiber such as 6 nylon or 66 nylon is used in the belt longitudinal direction. Multifilament yarns of polyamide fiber are also used for the wefts arranged in the direction and the warps arranged in the belt width direction. Furthermore,
Recently, a multifilament yarn of aramid fiber is used for the warp, and a toothed belt using this tooth cloth is disclosed in, for example, Japanese Patent Application Laid-Open No. 4-8948. The use of spun yarn of aramid fiber and urethane elastic yarn for the weft of the tooth cloth is disclosed in Japanese Patent Publication No. 1-1054. By improving the materials such as rubber elastic body, tooth cloth, and core wire, the heat resistance, wear resistance, and chipping resistance of the belt have been greatly improved, but there is a limit to this, and the belt shape is limited. Is also under consideration.

Further, in the shape of the conventional toothed belt, the tooth pitches of 8.0 mm and 9.525 mm are provided on the virtual pitch line when the belt is running under a predetermined tension. . The virtual pitch line at that time is a virtual distance in which the distance (PLD value) from the bottom surface of the belt tooth to the pitch line is set to 0.686 mm in a state where the belt tooth portion and the pulley groove portion are meshed with each other. Therefore, in the cross-sectional dimension of the belt, the distance from the tooth bottom surface to the center of the cord is 0.
It is usually set to be 686 mm, but under no tension, the distance from the tooth bottom surface of the belt to the center of the core wire is 0.68.
It was 0.72 mm.

[0006]

However, when the above-mentioned toothed belt is run, the bottom surface of the belt tooth surface abuts or collides with the top portion of the pulley tooth, causing the bottom surface of the belt to cause friction and wear, and the core wire to cause friction. It suffered mechanical damage and thermal deterioration due to the effect of heat generation. When the belt meshes with the pulley and receives a predetermined tension, the PLD of the belt decreases, but the decrease amount is small and does not reach 0.686 mm, and the flex fatigue resistance of the belt does not improve. It was
One of the reasons for this is that the thickness of the tooth cloth is unlikely to change. Further, when the rubber layer is interposed between the tooth cloth and the core wire, the PLD decreases in proportion to the magnitude of the belt tension, so that it is necessary to adjust the magnitude of the tension. The present invention solves such a problem by changing the thickness of the tooth cloth by the belt tension to maintain the desired PLD, and suppressing the wear of the tooth cloth even after the belt travels to change the PLD. It is an object of the present invention to provide a toothed belt which has a small size, improved flex fatigue resistance of the belt, and extended running life.

[0007]

That is, according to the present invention, a plurality of tooth portions arranged along the length direction, a back portion in which a core wire is embedded, and a tooth cloth covering the surfaces of the tooth portion and the tooth bottom are covered. In the toothed belt consisting of at least one of the warp yarns arranged in the belt width direction and the weft yarns arranged in the belt longitudinal direction of the above-mentioned tooth cloth, the spun yarn is 10 to 60 of the total fiber weight.
% By weight, and when the belt is not subjected to tension, the PL of the belt from the bottom surface of the belt to the center of the core wire
D is set to a value 5 to 30% larger than the set value of PLD used when setting the outer diameter of the meshing pulley, and the PLD of the belt decreases when the belt meshes with the pulley and receives tension. On the belt.

Further, according to the present invention, the PLD of the belt is 0.7.
If it is 3 to 0.85 mm or the PLD of the belt is 10
When a belt tension of up to 30 kgf is applied, the value decreases to the set value of the PLD used when setting the outer diameter of the pulley, and the spun yarn includes a toothed belt made of aramid fiber.

[0009]

1 is a side view of a toothed belt according to the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. The toothed belt 1 has a plurality of tooth portions 2 along the belt longitudinal direction,
It has a back part 4 in which the core wire 3 is embedded, and a tooth cloth 5 covering the surfaces of the tooth part surface 6 and the tooth bottom part 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, and 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 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. . Further, as an organic fiber, a filament of 0.5 to 2.5 denier of a para-aramid fiber (trade name: Kevlar, Technora) having a small elongation with respect to stress and a large tensile strength is twisted, and an RFL solution, an epoxy solution A twisted cord treated with an adhesive of an isocyanate solution and a rubber compound is used. However, the present invention is not limited to these. The core wire 3 has a diameter of 0.6 to 1.10 mm.
However, if it is less than 0.6 mm, the tensile strength of the core wire 3 is low and it cannot withstand high load transmission. On the other hand, if it exceeds 1.10 mm, it does not hold in terms of belt dimensions.

The canvas used as the tooth cloth 5 contains spun yarn as at least one of warp yarn (belt width direction) and weft yarn (belt length direction) in an amount of 10 to 60% by weight of the total fiber weight. The spun yarn is also made of polyamide fiber, polyester fiber, and aramid fiber, and is preferably aramid fiber having excellent abrasion resistance. The aramid fibers include, as trade names, Conex, Technora, Twaron, and Kevlar.

The content of spun yarn is 10% by weight of the total fiber weight.
When it is less than 10 to 30
Even when the belt tension of kgf is applied, it becomes difficult to reduce the set value of the PLD used when setting the outer diameter of the pulley, and abnormal wear of the tooth cloth easily occurs. Also, if the belt tension exceeds 60% by weight, the PLD of the belt tends to change, and the PLD used when setting the outer diameter of the pulley decreases below the set value of PLD. Is likely to occur.

Fibers other than the spun yarn are monofilaments and multifilaments such as 6 nylon, 66 nylon, polyester and aramid fibers. The woven structure of the tooth cloth 5 may be any of plain weave, twill weave, and satin weave.
A part of elastic urethane elastic yarn may be used as the weft yarn.

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. Latex such as vinylpyridine terpolymer, hydrogenated nitrile rubber, chlorosulfonated polyethylene, epichlorohydrin.

In the toothed belt of the present invention, however, the PLD from the tooth bottom surface 9 of the belt to the center of the core wire 3 is
Is a value that is 5% to 30% larger than the set value of the PLD used when setting the outer diameter of the meshing pulley when the belt is not subjected to tension. If the set value of PLD is 0.686 mm, the PLD value of the belt is 0.7
It is in the range of 3 to 0.85 mm. If the belt PLD
Is less than 5%, which is the size of a conventional toothed belt,
On the other hand, if it exceeds 30%, tooth breakage is likely to occur due to an impact caused when the belt and the pulley are meshed with each other. When the belt meshes with the pulley and receives a tension of 10 to 30 kgf, the PLD of the belt decreases due to the decrease in the thickness of the tooth cloth 5, and the PLD setting value is 0.6.
It approaches 86 mm. For that purpose, the spun yarn is used as at least one of the warp yarn and the weft yarn in the tooth cloth 5 in an amount of 1
0 to 60% by weight, which reduces the thickness of the tooth cloth 5 appropriately.

[0017]

The present invention will be described below in detail with reference to examples. Examples 1 to 6 and Comparative Example 1 A canvas having the composition shown in Table 1 was treated with an RFL treatment liquid [resorcin 1
1.0 parts by weight, formalin (37%) 8.0 parts by weight, caustic soda 0.2 parts by weight, styrene. butadiene. 84.0 parts by weight of a terpolymer of vinyl pyridine (40%), chlorosulfonated polyethylene rubber latex (40%)
%) 56.0 parts by weight, water 121.5 parts by weight], dried, and then heat-treated at 200 ° C. for 3 minutes, and further rubber paste (100 parts by weight of the rubber compound shown in Table 2 and 680 parts by weight of methyl ethyl ketone). , PAPI-13520 parts by weight) and air-dried to obtain a tooth cloth.

[0018]

[Table 1]

Next, three glass fibers of ECG150 were aligned as a core wire, dipped in the RFL treatment solution, air-dried, and
Heat-treated at 280 ° C for 1.5 minutes, S direction, Z
Prepare 11 individual ropes twisted as a lower twist at a rate of 12 times / 10 cm in each direction. The lower twist is the S direction in the Z direction, and the lower twist is the Z direction in the Z direction. The glass cord twisted in the direction of 8 times / 10 cm in each direction was used as the core wire. As the material for the back rubber and the tooth rubber, the rubber compound shown in Table 2 was used as a 3.0 mm sheet.

[0020]

[Table 2]

Each of the tooth cloths shown in Table 1 was finished into an endless tubular body, which was set in a mold. From above, a pair of S,
Z-twisted glass core wires are alternately wound spirally at a winding tension of about 10 kg / piece at a pitch of 1.3 mm, and a 3.0 mm rubber sheet is stuck on the spirally wound vulcanization sleeve by the conventional vulcanization method. After being molded, each of the belts was cut into a predetermined width in a ring shape to produce individual belts. The produced belt size is 105S8M19 (number of teeth: 105, belt width: 19.1 mm, tooth pitch: 8 m).
m, the tooth profile of the belt: STPD).

In order to measure the PLD value of the manufactured belt, the belt was cut and the distance from the tooth bottom surface of the belt cross section to the center of the cord was determined by a projector. Further, the belt is a driving pulley (21 teeth) and a driven pulley (42 teeth).
The belt was engaged with a tension pulley (pulley diameter 52 mmφ), and the driving pulley was rotated at an ambient temperature of 120 ° C. of 7,200 rpm, the driven pulley was loaded with 5 ps, and the belt had an initial tension of 15 kgf. . Then, the appearance of the belt after running for 1,000 hours and the thickness of the tooth cloth at the tooth bottom were determined by a projector. From this result, the difference in the thickness of the tooth cloth before and after running was divided by the thickness of the tooth cloth before running to obtain the tooth cloth thickness residual rate. Further, the length of the belt is an axial distance when the belt is hung on a pulley to apply tension, and the length in Table 3 shows a variation value from a reference value. Furthermore, the quietness during running of the belt was evaluated by measuring the sound pressure when the number of rotations of the drive pulley was 3,000 rpm in the running tester at a position 100 cm immediately before the drive pulley. Table 3 shows the results.

[0023]

[Table 3]

From this result, in the present embodiment in which spun yarn is used for the tooth cloth, the PLD is used even though the belt length is almost the same.
Is a large value, but it is estimated that the meshing during running is good as seen in the appearance of the belt after running. Normally, when a belt using a tooth cloth made of only filament yarns has the same length and PLD differs by 5% or more, the same meshability cannot be obtained and abnormal wear occurs. However, as in the present embodiment, If you use tooth cloth with spun yarn, PLD
Even if the difference is 5% or more, it is considered that abnormal wear or the like does not occur because the PLD of the belt decreases due to the tension. Moreover, as a result of the pronunciation test during running, the belt of this example has a low sounding property and is excellent in quietness.

[0025]

As described above, according to the present invention, when the belt is not subjected to tension, the PLD of the belt is a value 5% to 30% larger than the set value of the PLD used when setting the outer diameter of the meshing pulley. Since the yarn of the tooth cloth contains spun yarn, the PLD of the belt decreases and approaches the set value when the belt is not subjected to tension. Meshes well, and because the aramid fiber is used for the spun yarn, it has good wear resistance and little change in the PLD of the belt, improving the bending fatigue resistance of the belt and extending the running life. be able to.

[Brief description of drawings]

FIG. 1 is a side view of a toothed belt according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 Toothed belt 2 Tooth part 3 Core wire 4 Back part 5 Tooth cloth 7 Tooth bottom part 9 Tooth bottom surface

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takeshi Murakami 4-1-21, Hamazoe-dori, Nagata-ku, Kobe Mitsuboshi Belt Co., Ltd.

Claims (4)

[Claims] 1. A toothed belt comprising a plurality of tooth portions arranged along a length direction, a back portion in which a core wire is embedded, and a tooth cloth covering a surface of a tooth portion and a surface of a tooth bottom. In the case where at least one of the warp yarn arranged in the belt width direction and the weft yarn arranged in the belt longitudinal direction contains spun yarn in an amount of 10 to 60% by weight of the total fiber weight, and the belt is not subjected to tension, The PLD of the belt, which is the distance from the tooth bottom surface to the center of the core wire, is set to a value that is 5 to 30% larger than the PLD setting value used when setting the outer diameter of the meshing pulley, and the belt meshes with the pulley. A toothed belt characterized in that the PLD of the belt decreases when subjected to tension. 2. The PLD of the belt is 0.73 to 0.85 m.
The toothed belt according to claim 1, which is m. 3. The toothed belt according to claim 1, wherein when the PLD of the belt receives a belt tension of 10 to 30 kgf, the PLD is reduced to the set value of the PLD used when setting the outer diameter of the pulley. 4. The toothed belt according to claim 1, wherein the spun yarn is made of aramid fiber.