JP2003090388A - Thermoplastic elastomer made toothed belt and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer made toothed belt with a reduced noise property by making it smoothly engage with a toothed pulley, and a manufacturing method thereof. SOLUTION: This toothed belt 1 has tooth parts 1b at constant pitches in the belt longitudinal direction and is constituted of a thermoplastic elastomer burying a conductor 1c in it, the thermoplastic elastomer contains organopolysiloxane, and this organopolysiloxane works as a lubricant, smoothly carrying out engagement with the toothed pulley, and thus reducing noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic elastomer toothed belt and a method for manufacturing the same, and more particularly to a thermoplastic elastomer toothed belt that smoothly meshes with a toothed pulley to reduce noise. The manufacturing method is related. It is related.

[0002]

2. Description of the Related Art In a toothed belt made of a thermoplastic elastomer such as thermoplastic polyurethane, an attempt has been made to reduce the friction coefficient of the surface by blending a lubricant with the thermoplastic elastomer in order to reduce noise generated during running. ing. Conventionally, lard, salad oil, and wax have been generally used as the lubricant. However, in the toothed belt made of the thermoplastic elastomer containing lard, the lard is raised on the surface of the belt and solidifies white to make the appearance of the belt very bad, and the effect of reducing noise during running is not sufficient. Bleed also occurs when using salad oil,
There is a problem that the abrasion resistance of the belt is poor.

Therefore, it is desired to develop a toothed belt made of a thermoplastic elastomer using a lubricant such as lard, salad oil and wax, which does not have any problem, and one of the proposals is JP-A-11-.
It is proposed in Japanese Patent No. 51122. This is a mixture of a urethane prepolymer with a stearic acid-based or oleic acid-based ester having a hydroxyl group as a lubricant, which prevents the lubricant from bleeding and scattering, reducing the effects of noise and wear. The effect can be obtained over a long period of time.

[0004]

However, as a result of the inventors of the present invention having studied the lubricant proposed in Japanese Patent Laid-Open No. 11-51122, it has been found that a system in which an urethane type prepolymer is mixed with an amine type curing agent is It has been found that when a lubricant is blended, the lubricant reacts with the urethane prepolymer and inhibits the reaction between the urethane prepolymer and the amine-based curing agent, so that the polymer cannot be made to have a high molecular weight.

The obtained toothed belt has a small tooth hardness, and the tooth surface is likely to be worn when meshing with the pulley.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a toothed belt made of a thermoplastic elastomer that smoothly engages with a toothed pulley to reduce noise, and a method for manufacturing the toothed belt. To aim.

[0007]

In the invention according to claim 1 of the present invention, the belt has tooth portions at a constant pitch in the longitudinal direction of the belt,
A toothed belt made of a thermoplastic elastomer having a core wire embedded therein, wherein the thermoplastic elastomer is a toothed belt made of a thermoplastic elastomer containing an organopolysiloxane. That is, the organopolysiloxane contained in the thermoplastic elastomer acts as a lubricant, smoothly meshes with the toothed pulley, and reduces noise.

In the invention according to claim 2, the organopolysiloxane is in a toothed belt made of a thermoplastic elastomer containing 0.01 to 10% by weight of the thermoplastic elastomer, and the addition amount of the organopolysiloxane is within this range. In that case, the effect as a lubricant can be sufficiently exerted.

According to a third aspect of the present invention, the axial distance between a pair of toothed mold wheels consisting of a first toothed mold wheel and a second toothed mold wheel having the same tooth profile is determined, and the pair of toothed mold wheels is set. A core wire is wound between the wheels to form a mold cavity by covering a part of the outer periphery of the first toothed mold wheel, and a thermoplastic elastomer is injected into the mold cavity to form the pair of toothed mold wheels. In the method for producing a toothed belt which forms a toothed belt along the cord by rotating, the thermoplastic elastomer is a method for producing a thermoplastic elastomer toothed belt containing an organopolysiloxane, Since the tooth portion of the toothed belt formed by the first toothed molding wheel contains the organopolysiloxane, the meshing with the second toothed molding wheel becomes smooth.

In the invention according to claim 4, as the thermoplastic elastomer, 0.01 to 10 of organopolysiloxane is used.
A method for producing a toothed belt made of a thermoplastic elastomer using a dry blend of a thermoplastic elastomer containing wt% and a thermoplastic elastomer containing no organopolysiloxane.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. As shown in FIG. 1, the thermoplastic elastomer toothed belt 1 has a back portion 1a made of a thermoplastic elastomer on the upper side of the core wire 1c, and a tooth bottom portion having a thickness corresponding to the nose height on the lower side. The tooth portions 1b having a constant pitch are arranged in the.

The thermoplastic elastomer used here is mainly one or two kinds of polyols selected from polyester polyols, polyamide polyester polyols, polycarbonate polyols, polyether polyols and the like having two or more active hydrogens in one molecule. It is a linear thermoplastic polyurethane obtained by reacting the above mixture with a polyfunctional isocyanate in an equimolar ratio, and has a number average molecular weight of 100,000 to 200,000. For example, long-chain dipolyols, short-chain dipolyols, and linear thermoplastic polyurethanes obtained from diisocyanates, where the long-chain dipolyols are soft segments of the elastomer and the short-chain dipolyols and diisocyanates are hard Form a segment.

Specifically, each may be a polyester (DuPont trade name: Hytrel, Toyobo trade name: Perprene, etc.) or polyamide (Daicel trade name: Daiamido PAE) thermoplastic elastomer. Further, it may be ethylene-α-olefin.

The thermoplastic elastomer contains 0.1 to 10 wt% of organopolysiloxane. That is, a thermoplastic resin pellet containing 1 to 70% by weight of a liquid organopolysiloxane at room temperature and a thermoplastic resin pellet not containing the organopolysiloxane have an organopolysiloxane content of 0.0.
The thing obtained by mixing and melting so that it might be 1-10 weight% was used. When the addition amount of the organopolysiloxane is less than 0.01% by weight, the effect of the addition of the organopolysiloxane is not effective as a lubricant.
When the content exceeds 5% by weight, the adhesive force between the core wire 4 and the thermoplastic elastomer decreases.

As the above-mentioned organopolysiloxane,
Typical examples are dimethyl polysiloxane, methyl alkyl polysiloxane, methyl vinyl polysiloxane,
Examples include methylphenyl polysiloxane and methyl (trifluoropropyl) polysiloxane. The molecular structure of the organopolysiloxane is typically linear, but may be branched. The organopolysiloxane used here is liquid or raw rubber at room temperature, and the viscosity is not particularly limited, but 10 cst or more is preferable.

The above-mentioned core wire is made of steel cord, aramid fiber, polyester fiber, glass fiber or the like, having a low elongation,
It consists of a high-strength rope and is immersed for 0.5 to 30 seconds in the first treatment liquid set to room temperature with an isocyanate compound and / or an epoxy resin, and then in an oven adjusted to 150 to 190 ° C for 2 to 5 minutes. Dried through and R
The treatment is performed with the second treatment liquid which is the FL liquid. The RFL solution is a mixture of an initial condensate of resorcin and formalin with rubber latex. In this case, it is preferable that the molar ratio of resorcin and formalin is 3/1 to 1/3 in order to enhance the adhesive force. The initial condensate of resorcin and formalin was mixed such that the resin content was 5 to 100 parts by weight with respect to 100 parts by weight of the rubber content of the rubber latex, and the total solid concentration was 5 to 40%. Adjusted.

An example of a method of manufacturing the thermoplastic elastomer toothed belt 1 according to the present invention will be described below in detail with reference to the drawings.

(First Step) Setting of Distance between Shafts In FIG. 2, the distance between the shafts of a pair of toothed mold wheels 2 including a first toothed mold wheel 2a and a second toothed mold wheel 2b having the same tooth profile. The distance is determined by sliding the slide base 22 so as to have a predetermined circumferential length.

(Second Step 1) Spinning Step In FIG. 2, the winding start portion of the core wire 1c fixes and locks a plurality of adjacent core wires 1c. The spinning mechanism 8 in the figure is operated. The S-twisted and Z-twisted core wires 1c are wound individually or in a set of two. The number of windings is 1c
It is automatically set according to the interval (pitch) and the manufacturing belt width. First toothed molding wheel 2a and second toothed molding wheel 2b
In between, the core wire 1c is spirally wound at a predetermined width at a predetermined core wire pitch, and a plurality of core wires 1c adjacent to each other at the winding end portion of the core wire 1c are locked to separate the core wire 1c. To form a just-arranged core wire array (construction of the core wire 1c).

At this time, the guide means 6 is in the withdrawal position of the chain double-dashed line, and the core wire aligning means 10 is in the second position P2. The core wire 1c used is mainly a steel cord, but a fiber of low elongation and high strength represented by aramid fiber, polyester fiber, or glass fiber can be used. This spinning process is performed by synchronous operation and high-speed rotation of the first toothed molding wheel 2a and the second toothed molding wheel 2b.

(Second Step 2) Core Wire Pitch Aligning Step After the spinning is completed, the comb 30 is set to the first position P1 and the first toothed molding wheel 2a and the second toothed molding wheel 2b are synchronously rotated at a low speed. Meanwhile, the misaligned core wires 1c are inserted into the grooves of the comb 30 to initialize the alignment of the core wires. The core wire aligning means 10 is installed so that the first position P1 is close to the pushing means 7.

(Third Step 1) Molten Resin Injection Step In FIG. 2, the guide means 6 is advanced to the operating position indicated by the solid line, and the mold cavity is formed between the steel band 26 and the tooth mold of the first toothed molding wheel 2a. And the molten thermoplastic elastomer 5 is extruded from the extruding means 7 into a flat plate shape while rotating the first toothed molding wheel 2a and the second toothed molding wheel 2b in the arrow direction at the same speed and at a low speed. Fill the mold cavity. The thermoplastic elastomer 5 includes
Although thermoplastic urethane is mainly used, a polyester elastomer or a polyamide elastomer can be used.

The filled elastomer 5 is compression-molded into a predetermined tooth shape and is cooled and solidified by the co-rotation of the steel band 26 and the rotation of the first toothed molding wheel 2a.

(Third Step No. 2) Core Wire Alignment Guide Step After the core wire row has been initialized in the above-mentioned core wire pitch alignment step, the frontmost end portion 15 of the toothed belt 1 has the comb 30. It is installed at the first position P1 until it reaches the position immediately before, and when the frontmost end reaches just before the comb 30, it is retracted to the second position P2 by the rotation of the swing arm 31. As a result, the core wire 1c is reliably aligned and guided over the entire circumference. The core wire array that is spirally wound around the circumference of the toothed belt 1 is laterally fed in one pitch width direction by a drive mechanism (not shown).

The core locking portion during spinning is formed by adhering or fixing the core wires 1c adjacent to each other.
It passes over the outer periphery of 0 and temporarily passes through the groove, but since the core wire 1c is pressed against the comb 30, it immediately fits in the original groove. Further, this locking portion is provided at the product trim portion.

(Third Step No. 3) Continuation of Molten Resin Injection Step The temperature of the thermoplastic elastomer 5 is lowered to about 50 ° C. at the outlet of the steel band 26 to form the toothed belt 1 as shown in FIG. , Is discharged from the end of the guide roll R2 of the steel band 26. In FIG. 1, a toothed belt 1
Is a structure in which the back portion 1a and the tooth portion 1b are integrally formed of a thermoplastic elastomer, and the core wire 1c is embedded substantially in the middle of the thickness of the back portion 1a.

(Fourth step) Process of fusing the front end and the rear end of the toothed belt In FIG. 2, the front end 15 of the toothed belt 1 is meshed with the second toothed mold wheel 2b, The first toothed molded wheel 2a goes around once. When the foremost end portion 15 merges and fuses with the rear end portion formed at the entrance of the steel belt 26,
A long endless toothed belt 1 having no connecting portion is formed.

(Fifth Step) Step of Taking Out Toothed Belt 1 The rotation of the first toothed molding wheel 2a and the second toothed molding wheel 2b is stopped, the guide means 6 is retracted, and the second toothed molding wheel is moved. 2b is slid toward the first toothed mold wheel 2a to loosen the thermoplastic elastomer toothed belt 1,
Take it out.

[0029]

EXAMPLE Next, a method for manufacturing a toothed belt made of a thermoplastic elastomer will be described as a specific example. Examples 1 to 3, Comparative Example 1

A toothed belt made of a thermoplastic elastomer was produced using the apparatus shown in FIG. With this method, about 90
0.3mm on a pair of toothed mold wheels heated to ° C
Spinning tension of core wire of φ steel cord 3k
g, spinning pitch 0.8 mm, spinning speed 20
After spirally winding at 0 rpm, dimethylpolysiloxane heated to 190 ° C (number average molecular weight about 500,000)
Of 0.2% by weight, 2% by weight and 5% by weight of thermoplastic polyurethane (number average molecular weight of about 130,000) were continuously cast from the extrusion means, and about 2 kg /
A toothed belt was produced while applying a pressure of cm ² . Since the tooth portion of the toothed belt molded by the first toothed molding wheel contains the organopolysiloxane, the meshing with the second toothed molding wheel could be performed smoothly. The toothed belt made of thermoplastic elastomer has a width of 100 mm and an outer peripheral length of 2
It was 000 mm, the number of teeth was 400, and the tooth type was STPD.

The toothed belt is driven by a drive pulley (the number of teeth is 3).
2), it was wound around a driven pulley (the number of teeth was 32) and the number of teeth meshing with the driven pulley was set to 16 teeth. In this way, the ambient temperature of the belt is room temperature, and the rotation speed of the drive pulley is 1
It was rotated at 800 rpm and measured by the sound pressure level at the time of meshing with the drive pulley. When the content of dimethylpolysiloxane was 0.2% by weight, it was 79 dB, and when it was 2% by weight, it was 7 dB.
At 6 dB and 5% by weight, it was 74 dB, and the meshing was smooth without abnormal noise. However, when a thermoplastic urethane containing no dimethylpolysiloxane is used,
It is 82 dB, which means that the sound level is slightly high and the slipperiness of the teeth is inferior.

[0032]

As described above, in the thermoplastic elastomer toothed belt according to the claims of the present invention, since the thermoplastic elastomer contains the organopolysiloxane, the organopolysiloxane acts as a lubricant. ,
It has the effect of reducing noise by smoothly engaging with the toothed pulley.

Further, in the method for manufacturing a toothed belt,
Since the toothed belt formed by the first toothed molding wheel contains organopolysiloxane in the tooth portion, it can be smoothly meshed with the second toothed molding wheel, and the workability is good. .

[Brief description of drawings]

FIG. 1 shows a perspective view of a toothed belt made of a thermoplastic elastomer according to the present invention.

FIG. 2 is a schematic view of an apparatus for manufacturing a toothed belt made of a thermoplastic elastomer according to the present invention.

[Explanation of symbols]

1 Toothed belt made of thermoplastic elastomer 1a back 1b Tooth 1c core wire

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Claims (4)

[Claims] 1. A toothed belt comprising a thermoplastic elastomer having tooth portions at a constant pitch in the longitudinal direction of the belt and having a core wire embedded therein, wherein the thermoplastic elastomer contains an organopolysiloxane. Toothed belt made of thermoplastic elastomer. 2. The toothed belt made of a thermoplastic elastomer according to claim 1, wherein the organopolysiloxane is contained in the thermoplastic elastomer in an amount of 0.01 to 10% by weight. 3. An axial distance between a pair of toothed mold wheels comprising a first toothed mold wheel and a second toothed mold wheel having the same tooth profile is determined, and a core wire is provided between the pair of toothed mold wheels. And a mold cavity is formed by covering a part of the outer periphery of the first toothed molding wheel, and the pair of toothed molding wheels is rotated while injecting a thermoplastic elastomer into the die cavity. A method of manufacturing a toothed belt made of a thermoplastic elastomer, wherein the thermoplastic elastomer contains an organopolysiloxane, wherein the toothed belt is formed along a line. 4. A thermoplastic elastomer, which is a dry blend of a thermoplastic elastomer containing 0.01 to 10% by weight of organopolysiloxane and a thermoplastic elastomer containing no organopolysiloxane. A method for manufacturing a toothed belt made of a thermoplastic elastomer.