JP6959203B2 - Manufacturing method of polyurethane transmission belt and mold equipment used for it - Google Patents

Description

The present invention relates to a method for manufacturing a polyurethane transmission belt and a mold device used for manufacturing.

Polyurethane transmission belts are widely used as power transmission belts for general industrial use, precision equipment, etc. because of their excellent appearance and less generation of wear debris. The polyurethane transmission belt includes a V-ribbed belt in which a plurality of V-shaped rib portions extending in the circumferential length direction of the belt are formed, and a toothed belt in which tooth portions and grooves are alternately formed at a constant pitch in the longitudinal direction of the belt. In each case, a core wire (twisted cord) made of a plurality of steel fibers, aramid fibers, etc. is embedded in the belt body formed of a polyurethane elastic body. Note that FIG. 1 shows a partially broken perspective view of a polyurethane toothed belt as an example of a polyurethane transmission belt.

A polyurethane transmission belt is made by casting a liquid polyurethane raw material (polyurethane composition), which is a mixture of a polyurethane prepolymer and a curing agent, into a mold and producing a polyurethane elastic body by a curing reaction by heating. Obtain a belt molded body.

As an example of a method for manufacturing a polyurethane transmission belt by a casting method, the procedure of Patent Document 1 can be mentioned. This procedure is as follows (1) to (5). As shown in FIG. 2, first, (1) a liquid polyurethane raw material is cast into the inside of an outer mold having a cylindrical inner peripheral surface. Next, (2) a cylindrical inner mold in which a core wire is spirally wound in advance is inserted into the outer mold. Then, (3) the gap (cavity, cavity) between the inner mold and the outer mold is filled with a liquid polyurethane raw material. Then, (4) a polyurethane elastic body is formed by a curing reaction at atmospheric pressure while applying heat to the polyurethane raw material to form a polyurethane belt sleeve in which a core wire is embedded. Finally, (5) the molded polyurethane belt sleeve is demolded, cooled, and then cut into a ring shape to a predetermined width to obtain a polyurethane transmission belt.

Japanese Unexamined Patent Publication No. 2005-172005 Japanese Unexamined Patent Publication No. 8-118363 Japanese Unexamined Patent Publication No. 11-156857

As for the above-mentioned polyurethane transmission belt, the load on the belt is increasing due to the narrowing of the belt due to the compact installation layout and the increase in the size of the machine. Therefore, the polyurethane used as the base material is used. Further improvement in wear resistance and mechanical properties is required.

In this regard, in the method for manufacturing a rubber transmission belt such as chloroprene rubber (CR) or ethylene propylene diene rubber (EPDM) (Patent Documents 2 and 3), the vulcanizer shown in FIG. 3 and the vulcanizer shown in FIG. 4 are shown. A method of vulcanizing while pressurizing an unvulcanized molding material containing a rubber composition may be adopted through a jacket using the vulcanized can shown below. According to this, the unvulcanized molding material containing the rubber composition is molded and solidified into a predetermined shape, and the transmission belt made of rubber having good quality can be obtained by making it dense without containing air bubbles.

For example, in the vulcanizing apparatus shown in FIG. 3, first, (1) a molding material such as an unvulcanized rubber sheet, a core wire, or a reinforcing cloth for forming a rubber layer is applied to a molding die (inner die), if necessary. Wrapped to form an unvulcanized laminate. Next, (2) a rubber jacket is placed on the outer peripheral side of the molding die around which the unvulcanized laminate is wound. Next, (3) by pressurizing the jacket with air or pressurized steam from the outer peripheral side of the jacket, the laminated body is vulcanized while the unvulcanized rubber sheet is pressed while the unvulcanized laminated body is pressed. The vulcanization belt sleeve is formed by integrating. Finally, (4) the molded belt sleeve is removed from the mold and cut into a ring shape to a predetermined width to obtain a rubber (CR or EPDM) transmission belt.

However, since the above vulcanization equipment and vulcanization can are used for vulcanization and pressurization on the premise of a solid unvulcanized rubber sheet, they can be used when vulcanizing a liquid polyurethane raw material. difficult.

Therefore, the present invention provides a method for manufacturing a polyurethane transmission belt, which can improve physical properties such as wear resistance of the polyurethane transmission belt produced from a liquid polyurethane raw material, and a mold device used for the method. do.

The present invention is a mold device for molding a polyurethane transmission belt by curing a liquid polyurethane raw material.
Internal type and
With an outer mold provided with a pressurizing jacket that can be pressurized,
When the inner mold and the outer mold are matched,
The liquid polyurethane raw material is filled between the pressurizing jacket provided on the outer mold and the inner mold to form a sealable cavity.

According to the above configuration, the cavity between the pressurizing jacket provided on the outer mold and the inner mold is filled with a liquid polyurethane raw material and sealed. Then, the sealed liquid polyurethane raw material can be cured in a state of being pressurized by the pressurizing jacket. As a result, the liquid polyurethane raw material is crosslinked in a pressurized state, so that the crosslinked structure of the polyurethane molecules becomes dense (the crosslink density increases), so that the polyurethane transmission belt has high physical properties such as abrasion resistance. Can be molded.
Further, since it is excellent in abrasion resistance, it is possible to mold a polyurethane transmission belt having a thickness thinner than that of the conventional one.

Further, the present invention relates to the above-mentioned mold apparatus.
The outer mold has a bottomed tubular shape capable of accommodating the inner mold.
The inner mold has a cylindrical shape and can be heated by a heating means. The pressurizing jacket is provided on the inner cylinder surface side of the outer mold.
Further, it is provided with an upper lid capable of sealing the outer mold containing the inner mold.

According to the above configuration, the pressurizing jacket is provided in an arc shape along the inner cylinder surface of the outer mold. Then, the polyurethane raw material is arranged between the pressure jacket provided in an arc shape and the outer peripheral surface of the inner mold having a cylindrical shape. As a result, the polyurethane raw material can be uniformly pressurized and heated. As a result, uniform wear resistance can be provided to the entire polyurethane transmission belt.

Further, the present invention is a method for manufacturing a polyurethane transmission belt using a mold device provided with an outer mold and an inner mold.
A raw material filling step in which a liquid polyurethane raw material is filled and sealed in a cavity between the pressurizing jacket provided on the outer mold and the inner mold.
It is characterized by including a pressure curing step in which the polyurethane raw material filled in the sealed cavity is cured in a pressurized state by the pressure jacket.

According to the above method, the cavity between the pressurizing jacket provided on the outer mold and the inner mold is filled with a liquid polyurethane raw material and sealed. Then, the sealed liquid polyurethane raw material can be cured in a state of being pressurized by the pressurizing jacket. As a result, the liquid polyurethane raw material is subjected to a cross-linking reaction in a pressurized state, so that the cross-linked structure of the polyurethane molecules becomes dense (the cross-linking density increases), so that the polyurethane transmission belt has high physical properties such as abrasion resistance. Can be manufactured.
Further, since it is excellent in abrasion resistance, it is possible to manufacture a polyurethane transmission belt having a thickness thinner than that of the conventional one.

Further, the present invention relates to the above method for manufacturing a polyurethane transmission belt.
The outer mold has a bottomed tubular shape capable of accommodating the inner mold.
The inner mold has a cylindrical shape and can be heated by a heating means.
The pressurizing jacket is provided on the inner cylinder surface side of the outer mold.
Further, an upper lid capable of sealing the outer mold containing the inner mold is provided.
In the raw material filling step, the outer mold containing the inner mold is sealed by covering the upper part of the outer mold with the upper lid.
The pressure curing step is characterized in that the polyurethane raw material filled in the cavity is cured by heating through the inner mold by the heating means in a state of being pressurized by the pressurizing jacket.

According to the above method, the pressurizing jacket is provided in an arc shape along the inner cylinder surface of the outer mold. Then, the polyurethane raw material is arranged between the pressure jacket provided in an arc shape and the outer peripheral surface of the inner mold having a cylindrical shape. As a result, the polyurethane raw material can be uniformly pressurized and heated. As a result, it is possible to manufacture a polyurethane transmission belt in which the entire belt has uniform wear resistance.

It is possible to provide a method for manufacturing a polyurethane transmission belt, which can improve physical properties such as wear resistance of the polyurethane transmission belt produced from a liquid polyurethane raw material, and a mold device used for the method.

It is a partially cutaway perspective view of the polyurethane toothed belt obtained by the manufacturing method of this embodiment. It is explanatory drawing of the manufacturing method of the polyurethane toothed belt by the conventional casting method. It is explanatory drawing of the manufacturing method of the rubber transmission belt using the conventional vulcanization apparatus. It is explanatory drawing of the manufacturing method of the rubber transmission belt using the conventional vulcanization can. It is explanatory drawing of the manufacturing method of the polyurethane toothed belt using the mold apparatus which concerns on this embodiment. It is explanatory drawing of the manufacturing method of the polyurethane toothed belt using the mold apparatus which concerns on this embodiment. It is explanatory drawing of the manufacturing method of the polyurethane toothed belt using the mold apparatus which concerns on this embodiment. It is explanatory drawing of the tabor wear test which concerns on Example. It is a partially cutaway perspective view of the polyurethane toothed belt provided with the reinforcing cloth obtained by the manufacturing method of this embodiment.

(Embodiment)
Hereinafter, a method for manufacturing a polyurethane transmission belt according to the present invention and a mold device used for the method will be described with reference to the drawings. In the present embodiment, the polyurethane toothed belt 1 will be illustrated and described as the polyurethane transmission belt to be manufactured.

(Polyurethane toothed belt 1)
As shown in FIG. 1, the polyurethane toothed belt 1 has tooth portions 3 and groove portions 4 alternately formed at a constant pitch in the longitudinal direction of the belt, and the belt body 2 (back) formed of a polyurethane elastic body. Inside, core wires 5 (twisted cords) made of steel fibers, aramid fibers, and the like are spirally embedded at predetermined intervals (pitch) in the belt width direction (or at equal intervals). The polyurethane toothed belt 1 is used by being wound between a plurality of pulleys such as a drive pulley and a driven pulley in a power transmission system such as a precision instrument.

The polyurethane elastic body (or urethane elastomer) constituting the belt body 2 and the tooth portion 3 is not particularly limited, and conventional polyurethane can be used, but from the viewpoint of moldability and the like, a cured product of the urethane prepolymer and the curing agent. (Two-component curable polyurethane) may be used.
The urethane prepolymer may be any prepolymer that can be cured with a curing agent, and a conventional prepolymer can be used. However, a prepolymer having an isocyanate group at the terminal (for example, a prepolymer having two or more isocyanate groups at the end) can be used. Polymer) is widely used.
The prepolymer having an isocyanate group at the terminal may be a polyurethane prepolymer obtained by reacting an excess amount of polyisocyanates with polyols.
Examples of the polyols include polyester polyols, polyether polyols, polyether ester polyols, polycarbonate polyols, polyesteramide polyols, acrylic polymer polyols and the like. These polyols can be used alone or in combination of two or more. Among these polyols, polyester diols and polyether diols are widely used, and polyether diols such as polytetramethylene glycol ether are preferable from the viewpoint of flexibility and water resistance.
Polyisocyanates include, for example, aliphatic diisocyanates such as aliphatic polyisocyanates [propylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI), lysine diisocyanate (LDI), etc. , 1,6,11-Undecantryisocyanate Methyloctane, 1,3,6-hexamethylene triisocyanate and other aliphatic triisocyanates], alicyclic polyisocyanate [cyclohexane 1,4-diisocyanate, isophorone diisocyanate (IPDI), Hydrocyclic diisocyanates such as hydrogenated xylylene diisocyanate and hydrogenated bis (isocyanatophenyl) methane, alicyclic triisocyanates such as bicycloheptane triisocyanate], aromatic polyisocyanates [phenylenediocyanate, tolylene diisocyanate (TDI) ), Xylylene diisocyanate (XDI), Tetramethylxylylene diisocyanate (TMXDI), Naphthalene diisocyanate (NDI), Bis (isocyanatophenyl) methane (MDI), Truisidine diisocyanate (TODI), 1,3-bis (isocyanatophenyl) ) Aromatic diisocyanates such as propane] and the like are included.
These polyisocyanates can be used alone or in combination of two or more. Among these polyisocyanates, aliphatic diisocyanates such as HDI, alicyclic diisocyanates such as IPDI, aromatic aliphatic diisocyanates such as XDI, and aromatic diisocyanates such as MDI and TDI are widely used in terms of mechanical properties and the like. , TDI and other aromatic polyisocyanates are particularly preferred.

As the curing agent, polyols and polyamines which are conventional curing agents can be used and can be selected according to the type of prepolymer, but polyamines are preferable from the viewpoint of reactivity and the like.
Examples of polyamines include aliphatic diamines (for example, ethylenediamine, propylenediamine, tetramethylenediamine, etc.), alicyclic diamines (for example, 1,4-cyclohexylenediamine, isophoronediamine, etc.), aromatic diamines (for example, for example). 4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA), phenylenediamine, etc.), aromatic aliphatic diamines (eg, m-xylylene diamine, etc.), triamines (diethylenetriamine, etc.) (Triethylenetetramine, tetraethylenepentamine, etc.) and the like.
These polyamines can be used alone or in combination of two or more. Among these polyamines, aromatic polyamines such as MOCA are particularly preferable from the viewpoint of reactivity and mechanical properties.

The urethane prepolymer and the curing agent usually have a ratio in which an isocyanate group and an active hydrogen atom (for example, an amino group) are substantially equivalent (isocyanate group / active hydrogen atom = about 0.8 / 1 to 1.2 / 1). It is used in combination with. The ratio of the curing agent can be selected from, for example, about 1 to 50 parts by mass with respect to 100 parts by mass of the urethane prepolymer, preferably about 3 to 30 parts by mass, and more preferably about 5 to 20 parts by mass.

As the core wire 5, a twisted cord of a multifilament yarn (for example, multiple twists, single twists, rung twists, etc.) can be used. The fibers constituting the core wire 5 are not particularly limited, and from the viewpoint of low elongation and high strength, for example, synthetic fibers such as polyester fiber, polyamide fiber and aramid fiber, and inorganic fibers such as steel fiber, glass fiber and carbon fiber. Fibers and the like are widely used.

In the above embodiment, the polyurethane toothed belt 1 in which the reinforcing cloth is not provided on the surfaces of the tooth portion 3 and the groove portion 4 has been described, but a reinforcing cloth (dental cloth) may be provided on the surfaces of the tooth portion 3 and the groove portion 4. Good (see Figure 9).

In this case, since the reinforcing cloth needs to be molded along the surfaces of the tooth portion 3 and the groove portion 4 at the time of manufacturing the polyurethane toothed belt, a thread (elastic thread) extending in the longitudinal direction of the belt is included. .. For example, a reinforcing cloth is composed of a woven cloth in which warp threads and weft threads are interlaced vertically and horizontally according to a certain rule. The weaving method of the woven fabric may be either twill weave or satin weave. The form of the warp and weft is either a multifilament yarn in which filaments (long fibers) are aligned or twisted, a monofilament yarn which is one long fiber, or a spun yarn (spun yarn) in which short fibers are twisted. You may. When the warp or weft is a multifilament yarn or a spun yarn, it may be a blended yarn or a blended yarn using a plurality of types of fibers. At least one of the weft and the warp may contain an elastic thread having elasticity. As the elastic yarn, for example, a yarn in which the material itself has elasticity such as spandex made of polyurethane, or a processed yarn in which fibers are stretch-processed (for example, woolly processing, winding processing, etc.) is used.

When the woven fabric is used as a reinforcing cloth for a polyurethane toothed belt, it is preferable to arrange the warp yarns containing no elastic yarns in the width direction of the belt and the weft yarns containing elastic yarns in the longitudinal direction of the belt. Thereby, the elasticity of the reinforcing cloth in the belt longitudinal direction can be ensured. As the material of the fibers constituting the reinforcing cloth, any one of nylon, aramid, polyester, polybenzoxazole, cotton and the like, or a combination thereof can be adopted.

Further, the woven fabric used as the reinforcing cloth may be subjected to a known adhesive treatment in order to enhance the adhesiveness with polyurethane.

(Mold device 10)
Next, the mold apparatus 10 used in the method for manufacturing the polyurethane toothed belt 1 will be described.

As shown in FIG. 5, the mold device 10 has a configuration including an inner mold 20, an outer mold 30, and an upper lid 40.

The inner mold 20 has a cylindrical shape, and a space portion 21 to which pressurized steam is supplied is provided inside. Further, a columnar upper convex portion 22 that fits into a hole 41 provided in the upper lid 40, which will be described later, is provided on the upper portion of the inner mold 20. The upper convex portion 22 is provided with two pipes 24 (pressurized steam supply path / discharge path) that communicate the space portion 21 and the outside of the inner mold 20. Further, a lower convex portion 23 that engages with a concave portion 33 formed in the bottom portion of the outer mold 30, which will be described later, is provided in the lower portion of the inner mold 20. Further, a plurality of grooves extending in the axial direction are formed on the outer peripheral surface of the inner die 20 (not shown). The tooth portions 3 and the groove portions 4 of the polyurethane toothed belt 1 can be molded by the plurality of grooves formed on the outer peripheral surface of the inner mold 20.

The outer mold 30 has a bottomed tubular shape capable of accommodating the inner mold 20, and a pressurizing jacket 31 (flexible member) is arranged on the inner peripheral surface thereof. A supply path 32 for supplying air to the pressurizing jacket 31 and a discharge port 36 for discharging air are formed on the outer peripheral surface of the outer mold 30. Further, the bottom of the outer mold 30 is provided with a recess 33 that engages with the lower convex portion 23 of the inner mold 20.

The upper lid 40 has a disk shape, and a hole 41 in which the upper convex portion 22 of the inner mold 20 housed in the outer mold 30 is fitted is formed in the central portion of the upper lid 40. The upper lid 40 covers the upper part of the outer mold 30 containing the inner mold 20 and is locked (fixed) to the outer mold 30 to seal the outer mold 30 containing the inner mold 20.

Here, as shown in FIG. 6, the inner mold 20 is housed inside the outer mold 30 (corresponding to a state in which the inner mold 20 and the outer mold 30 are matched), and the upper lid 40 is locked to the outer mold 30. In this state, a cavity 35 is formed between the pressurizing jacket 31 arranged on the inner peripheral surface of the outer mold 30 and the outer peripheral surface of the inner mold 20. The cavity 35 is used as a space filled with a liquid polyurethane raw material, and can form a closed state.

Although not shown, the mold device 10 has an air pump that supplies air (pressure medium) to the pressurizing jacket 31 via a supply path 32, and pressurized water to the space 21 of the inner mold 20 via a pipe 24. A pressurized water reactor (heating means) that supplies steam is connected. In the present embodiment, the inner mold 20 is heated by using a pressurized steam supply device as the heating means, but a configuration in which the cavity 35 is heated may be adopted, and the outer mold 30 and the upper lid 40 may be used. A configuration provided with heating means may be used.

(Production method)
Next, a method of manufacturing the polyurethane toothed belt 1 using the mold device 10 will be described.

First, the liquid polyurethane raw material 50 is prepared. In the present embodiment, the liquid polyurethane raw material 50 is cured by mixing a polyurethane prepolymer (polyether-based urethane prepolymer, etc.) with a thermoplastic agent (bis (DOA) adibate, etc.) and stirring and mixing the liquid raw material. A liquid raw material in which an agent (3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA)) is dissolved is prepared by stirring and mixing.

Then, as shown in FIG. 5, the liquid polyurethane raw material 50 is filled inside the outer mold 30 of the mold apparatus 10.

Next, the inner mold 20 in which the core wire 5 is spirally wound around the outer peripheral surface in advance is inserted into the outer mold 30, and the inner mold 20 is housed inside the outer mold 30. Then, the liquid polyurethane raw material 50 stored in the bottom of the outer mold 30 is formed in the cavity 35 formed between the pressurizing jacket 31 arranged on the inner peripheral surface of the outer mold 30 and the outer peripheral surface of the inner mold 20. Be pushed away. As a result, the liquid polyurethane raw material 50 fills the cavity 35 (see FIG. 6). After that, as shown in FIG. 6, the upper portion of the outer mold 30 is covered with the upper lid 40, and the upper lid 40 is locked (fixed) to the outer mold 30 to accommodate the inner mold 20 and the liquid polyurethane raw material 50. Is sealed (raw material filling process).

Next, the pressurized steam supply device supplies pressurized steam to the space 21 of the inner mold 20 via the pipe 24, and the temperature of the outer peripheral surface of the inner mold 20 is set to 90 to 120 ° C. (FIG. 7). reference).

Further, an air pump supplies air at a predetermined pressure to the pressurizing jacket 31 via the supply path 32 (see FIG. 7). For example, the pressure for pressurizing the polyurethane raw material 50 by the pressurizing jacket 31 is set to 0.3 to 0.9 MPa, and the pressurizing time is set to 20 to 60 minutes.

As a result, as shown in FIG. 7, the liquid polyurethane raw material 50 sealed in the cavity 35 is cured by heating through the outer peripheral surface of the inner mold 20 in a state of being pressurized by the pressurizing jacket 31. As a result, a tubular belt sleeve in which the core wire 5 is embedded is formed (pressure curing step).

After that, the lock of the upper lid 40 is released, and the inner mold 20 having the belt sleeve attached to the outer peripheral surface is taken out from the outer mold 30. Then, the belt sleeve is removed from the inner mold 20, cooled, and then cut into a ring shape to a predetermined width to obtain a polyurethane toothed belt 1. Regarding the method of removing the belt sleeve, after unlocking the upper lid 40, the belt sleeve is attached to the inner peripheral surface side of the outer mold 30, and only the inner mold 20 is taken out from the outer mold 30. A method of removing the belt sleeve from the outer mold 30 may also be used.

In the case of manufacturing the polyurethane toothed belt 1 provided with the reinforcing cloth, in the raw material filling step, the reinforcing cloth which has been formed into a cylindrical shape in advance is arranged on the outer peripheral surface of the inner mold 20, and then the reinforcing cloth is used. The inner mold 20 in which the core wire 5 is spirally wound around the outer peripheral surface is inserted into the outer mold 30, and the inner mold 20 is housed inside the outer mold 30. As a result, the pressurization of the pressurizing jacket 31 is used to form the tooth portion 3 of the polyurethane toothed belt 1, and the reinforcing cloth (tooth cloth) is also in a state of being along the surfaces of the tooth portion 3 and the groove portion 4. It can be typed (see FIG. 9).

(effect)
According to the mold apparatus 10 and the manufacturing method, the sealed liquid polyurethane raw material 50 can be cured in a state of being pressurized by the pressurizing jacket 31. As a result, the liquid polyurethane raw material 50 is subjected to a cross-linking reaction in a pressurized state, so that the cross-linked structure of the polyurethane molecules becomes dense (the cross-linking density increases), so that the polyurethane teeth have high physical properties in terms of wear resistance and the like. Attached belt 1 (polyurethane transmission belt) can be manufactured. Further, since it is excellent in abrasion resistance, it is possible to manufacture a polyurethane toothed belt 1 having a thickness thinner than that of the conventional one.

Further, the pressurizing jacket 31 is provided in an arc shape along the inner cylinder surface of the outer mold 30. Then, the liquid polyurethane raw material 50 is arranged between the pressurizing jacket 31 provided in an arc shape and the outer peripheral surface of the inner mold 20 having a cylindrical shape. As a result, the polyurethane raw material 50 can be uniformly pressurized and heated. As a result, it is possible to manufacture a polyurethane toothed belt 1 in which the entire belt has uniform wear resistance.

As described above, by pressurizing and heating the polyurethane raw material 50 from the pressurizing jacket 31 side to the outer peripheral surface side of the inner mold 20, the polyurethane raw material 50 can be uniformly pressurized and heated. If the thickness of the produced polyurethane toothed belt 1 is too large, the effects of pressurization and heating may not be sufficiently transmitted to the inner peripheral side of the polyurethane toothed belt 1. That is, the crosslink density may not be uniform in the thickness direction of the polyurethane toothed belt 1 (between the back and the teeth).

Therefore, in order to fully exert the effect of the manufacturing method of the present invention, the "back thickness" and "tooth height", which are the dimensions in the thickness direction of the polyurethane toothed belt 1, and further, the "tooth pitch (tooth pitch) The optimum size is assumed for "the distance between the tooth portion 3 and the tooth portion 3 in the longitudinal direction of the belt)" (see FIG. 1). In general, in the product system of a toothed belt, the "tooth pitch" is defined by a standard or the like as an index (name) indicating the scale of the belt, so that a person skilled in the art has a large "tooth pitch". The larger the tooth part (the larger the "tooth height"), the larger the "back thickness".

Specifically, in the case of a product system of a toothed belt such as a polyurethane toothed belt 1, the "back thickness" is preferably in the range of 0.8 mm to 1.9 mm, and the "tooth pitch" is The range is preferably 2.0 mm to 8.0 mm, the "tooth height" is preferably the range of 0.8 mm to 2.9 mm, and the "belt circumference" is the range of 300 mm to 1000 mm. Is preferable.

Next, a belt sleeve molded by using the mold device 10 (with a jacket for pressurization) of the above embodiment is set as Example 1, and a belt sleeve molded by a conventional casting method (see Patent Document 1) (FIG. 2). A wear resistance test was carried out using reference (without a pressurizing jacket) as a comparative example.

The dimensions of the belt sleeve of Example 1 and the belt sleeve of Comparative Example are that the back thickness is 1 mm, the tooth pitch (distance between the teeth) is 5 mm, the number of teeth is 124, and the circumference length is 620 mm. , The belt sleeve length was set to 200 mm.

(Manufacturing method of belt sleeve of Example 1)
As the method for manufacturing the belt sleeve of the first embodiment, the manufacturing method described in the above embodiment was adopted.

Specifically, the liquid polyurethane raw material 50 is a liquid raw material obtained by blending 100 parts by mass of a polyether urethane prepolymer with 25 parts by mass of bis (DOA) adibate as a thermoplastic agent and stirring and mixing at 60 ° C. As a curing agent, a liquid raw material prepared by dissolving 12.5 parts by mass of 3,3'-dichloro-4,4'-diaminodiphenylmethane (MOCA) at 120 ° C. was stirred and mixed.

Then, as shown in FIG. 5, the inside of the outer mold 30 of the mold apparatus 10 was filled with the liquid polyurethane raw material 50.

Next, the inner mold 20 in which a steel core wire 5 (core wire diameter: 0.32 mm) is spirally wound at an interval of 0.6 mm is spirally wound around the outer peripheral surface of the inner mold 20 in which a plurality of grooves are formed. It was inserted into the mold 30 and the inner mold 20 was housed inside the outer mold 30. As a result, the liquid polyurethane raw material 50 was filled in the cavity 35 (see FIG. 6). After that, as shown in FIG. 6, the upper portion of the outer mold 30 is covered with the upper lid 40, and the upper lid 40 is locked (fixed) to the outer mold 30 to accommodate the inner mold 20 and the liquid polyurethane raw material 50. Was sealed (raw material filling process).

Next, the pressurized steam supply device was used to supply pressurized steam to the space 21 of the inner mold 20 via the pipe 24, and the temperature of the outer peripheral surface of the inner mold 20 was set to 110 ° C. (see FIG. 7). ..

Further, air was supplied to the pressurizing jacket 31 through the supply path 32 by an air pump at a pressure of 0.8 MPa (see FIG. 7).

Then, as shown in FIG. 7, the liquid polyurethane raw material 50 sealed in the cavity 35 was cured by heating through the outer peripheral surface of the inner mold 20 for 60 minutes in a state of being pressurized by the pressurizing jacket 31. .. As a result, a tubular belt sleeve in which the core wire 5 was embedded was formed (pressure curing step).

After that, the lock of the upper lid 40 was released, and the inner mold 20 having the belt sleeve attached to the outer peripheral surface was taken out from the outer mold 30. Then, the belt sleeve was removed from the inner mold 20 and cooled to obtain the belt sleeve of Example 1.

(Manufacturing method of belt sleeve of comparative example)
As a method for manufacturing the belt sleeve of the comparative example, the belt of the first embodiment is used except that a mold device not provided with the pressurizing jacket 31 and a pressurizing step by the pressurizing jacket 31 are not provided. The same method as the sleeve manufacturing method was adopted.

(Abrasion resistance test (Taber wear test): JIS K7204)
A test piece having a size of 100 × 100 mm was taken from the produced belt sleeves of Example 1 and Comparative Example, and as shown in FIG. 8, the back surface of the belt was placed on the wear wheel, and the Taber wear test was carried out. As an evaluation, the wear loss of the test piece after 1000 rotations of the test piece was measured. The test conditions are shown in Table 1 and the test results are shown in Table 2.

As a result of the wear resistance test, it was found that the belt sleeve of Example 1 had less wear loss and was superior in wear resistance to the belt sleeve of Comparative Example.

(Verification of the size of a polyurethane toothed belt to which the manufacturing method of the present invention can be applied)
In order to verify the size of the polyurethane toothed belt to which the manufacturing method of the present invention can be applied, Examples 1 to 5 have different "back thickness", which is a dimension in the thickness direction of the polyurethane toothed belt. A belt sleeve was manufactured, and the above wear resistance test (Taber wear test) was performed on a test piece having a size of 100 × 100 mm collected from each belt sleeve.

Specifically, as shown in Table 3, Example 1 (belt sleeve with "back thickness" of 1 mm and "tooth pitch" of 5 mm) and Example 2 ("back thickness" of 0.8 mm, "tooth pitch"). 2 mm belt sleeve) and Example 3 (belt sleeve having a “back thickness” of 1.9 mm and a “tooth pitch” of 8 mm) were manufactured. Further, the belt sleeve of Example 4 was manufactured by arranging a reinforcing cloth (tooth cloth) on the surfaces of the tooth portion and the groove portion with respect to the belt sleeve of Example 3 (see FIG. 9). Further, a belt sleeve manufactured at a pressure as low as 0.3 MPa with respect to the belt sleeve (0.8 MPa) of Example 3 was designated as Example 5.

As the reinforcing cloth used in the belt sleeve of Example 4, a twill woven cloth was used, and the warp threads of the woven cloth were arranged so as to extend in the belt width direction and the weft threads in the belt longitudinal direction. As the weft of the woven fabric, a multifilament yarn having a fineness of 155 dtex of 66 nylon and a multifilament yarn having a fineness of 122 dtex of spandex (polyurethane elastic fiber) were used. As the warp yarn of the woven fabric, a 66 nylon multifilament yarn having a fineness of 155 dtex was used. The dtex is the mass of a yarn of 10,000 meters expressed in grams.

Regarding the methods for manufacturing the belt sleeves of Examples 2, 3 and 5, the size of the belt sleeve and the aramid core wire (core wire diameter: in Example 2) are attached to the belt sleeve. 0.25 mm, 1.0 mm in Example 3, 1.0 mm in Example 5) at predetermined intervals (0.5 mm in Example 2, 0.7 mm in Example 3, 0.7 mm in Example 5) The same method as the method for manufacturing the belt sleeve of Example 1 was adopted except that the belt sleeve was embedded in a spiral shape (see Table 3). Regarding the method for manufacturing the belt sleeve provided with the reinforcing cloth of Example 4, the size of the belt sleeve and the reinforcing cloth previously tubularized in the raw material filling step are arranged on the outer peripheral surface of the inner mold 20. Then, the inner mold 20 in which the aramid core wire 5 (core wire diameter: 1.0 mm) is spirally wound around the outer peripheral surface of the reinforcing cloth at an interval of 0.7 mm is inserted into the outer mold 30. The same manufacturing method as in Example 1 was adopted except that the inner mold 20 was housed inside the outer mold 30 (see Table 3).

It was found that the belt sleeves of Examples 1 to 5 all had less wear loss and were excellent in wear resistance as compared with the belt sleeves of the comparative example in which no pressurization was applied. In the process of manufacturing the belt sleeves having the dimensions of Examples 1 to 5, the polyurethane raw material is cross-linked in a state of being pressurized by a pressure jacket, so that the polyurethane teeth have high physical properties such as wear resistance. It was confirmed that the belt could be manufactured (the size of the polyurethane toothed belt to which the manufacturing method of the present invention could be applied could be confirmed).

1 Polyurethane toothed belt 10 Mold device 20 Inner mold 21 Space part 22 Upper convex part 23 Lower convex part 24 Piping 30 Outer mold 31 Pressurizing jacket 32 Supply path 33 Concave 35 Cavity 36 Discharge port 40 Top lid 41 Hole 50 Liquid Polyurethane raw material

Claims (4)

A mold device that cures a liquid polyurethane raw material to form a polyurethane transmission belt.
Internal type and
With an outer mold provided with a pressurizing jacket that can be pressurized,
When the inner mold and the outer mold are matched,
A mold device in which the liquid polyurethane raw material is filled between the pressurizing jacket provided on the outer mold and the inner mold to form a sealable cavity. The outer mold has a bottomed tubular shape capable of accommodating the inner mold.
The inner mold has a cylindrical shape and can be heated by a heating means. The pressurizing jacket is provided on the inner cylinder surface side of the outer mold.
The mold device according to claim 1, further comprising an upper lid capable of sealing the outer mold containing the inner mold. A method for manufacturing a polyurethane transmission belt using a mold device having an outer mold and an inner mold.
A raw material filling step in which a liquid polyurethane raw material is filled and sealed in a cavity between the pressurizing jacket provided on the outer mold and the inner mold.
A method for producing a polyurethane transmission belt, which comprises a pressure curing step in which the polyurethane raw material filled in the sealed cavity is cured in a pressurized state by the pressure jacket. In the mold device
The outer mold has a bottomed tubular shape capable of accommodating the inner mold.
The inner mold has a cylindrical shape and can be heated by a heating means.
The pressurizing jacket is provided on the inner cylinder surface side of the outer mold.
Further, an upper lid capable of sealing the outer mold containing the inner mold is provided.
In the raw material filling step, the outer mold containing the inner mold is sealed by covering the upper part of the outer mold with the upper lid.
The pressure curing step is characterized in that the polyurethane raw material filled in the cavity is cured by heating through the inner mold by the heating means in a state of being pressurized by the pressurizing jacket. The method for manufacturing a polyurethane transmission belt according to claim 3.

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