JP7115996B2 - Toothed belt manufacturing method and toothed belt manufacturing apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a rubber toothed belt and a manufacturing apparatus for the toothed belt.

Conventionally, for example, as a transmission belt used for synchronous transmission of general industrial machines that transmit a high load by a belt, a plurality of teeth provided at predetermined intervals in the longitudinal direction of the belt and a back portion in which a core wire is embedded A rubber toothed belt is generally known which includes a belt body made of a rubber composition having a base material and a tooth cloth covering the surfaces of the plurality of tooth portions.

Conventionally, as a method for manufacturing such a rubber toothed belt, a cylindrical mold (toothed mold) provided with a plurality of recesses (tooth profile) for forming tooth portions on the outer peripheral surface is used. After covering the outer peripheral surface of the belt with a cylindrical tooth cloth, a core wire that is a twisted yarn cord is spirally wound (spinning) on the tooth cloth, and a rubber sheet (not yet After forming an unvulcanized belt sleeve by winding a vulcanized material), a separately known vulcanization method, for example, expanding a bladder provided on the outer peripheral side of this unvulcanized belt sleeve and applying the pressure to the rubber A sheet (unvulcanized product) is press-fitted into the recesses of the mold through the gaps between the core wires and heated while forming teeth to obtain a vulcanized belt sleeve that will become the toothed belt (conventional method). .

However, since rubber sheets (unvulcanized) are used as the base material for the belt body, a series of complicated processes are required, including sheeting with rolling equipment such as calender rolls, cutting, winding around molds, and jointing. However, it is difficult to save labor, and problems remain in terms of productivity and manufacturing costs.

In order to satisfy productivity, it is necessary to continuously obtain an unvulcanized belt sleeve (for example, an effective surface length of 400 mm) having a sufficient effective length (effective surface length) corresponding to the number of belts to be taken.

In this regard, Patent Literature 1 discloses a method for continuously obtaining an unvulcanized belt sleeve by extrusion molding, in which the outer peripheral surface of a cylindrical mold is coated with an unvulcanized rubber composition in a layer. Therefore, based on the method described in Patent Document 1, by extrusion molding, a tooth cloth is attached to a mold (toothed mold), and a core wire is spun thereon. continuously supplied to the inside of the extruder main body to coat and mold a rubber composition (unvulcanized product) thermoplasticized by the extruder body, and vulcanize this unvulcanized belt sleeve by a known method It is conceivable to obtain a rubber toothed belt by

Japanese Patent No. 3998344

However, the method for obtaining an unvulcanized belt sleeve described in Patent Document 1 is not suitable for manufacturing flat belts such as transfer belts (semiconductive rubber belts) in which only a rubber composition is used as a constituent material of the belt body. This method is considered to be compatible with productivity. Therefore, there is no description or mention as to whether or not the present invention can be applied to the production of a rubber toothed belt having core wires and tooth cloth as constituent materials in addition to the rubber composition that is the base material of the belt body. was unknown.

Therefore, the inventor of the present application uses a toothed mold as a mold in an extrusion molding method using a general crosshead extruder (hereinafter referred to as a conventional extrusion method), and a cylindrical tooth cloth is formed on the outer periphery of this mold. The spun metal mold, in which the cord is spun on the tooth cloth, is continuously supplied to the inside of the inner cylindrical portion of the crosshead, and the rubber composition (unvulcanized product) is applied to the outer peripheral surface of the crosshead without any problems. An attempt was made to see if it was possible to perform covering molding (corresponding to Comparative Example 1 described later: see FIGS. 13 and 14).

As a result, it was found that an unvulcanized belt sleeve (effective surface length of 400 mm) in which a rubber composition (unvulcanized material) was formed in layers on the outer peripheral surface of a spun metal mold could be continuously molded. It could be confirmed. In addition, there was no problem with the uniformity of the thickness of the coating rubber layer and the adhesion to the cord.

However, when a cross-section along the length (surface length) direction of this unvulcanized belt sleeve was observed, it was confirmed that pitch disturbance (displacement in the longitudinal direction of the mold) occurred in the cord. A belt with such an irregular pitch of the core wires cannot be used as a power transmission belt and is scrapped.

The reason why the pitch disturbance occurred in the core wire as described above is considered as follows. The rubber composition (unvulcanized product) that has been thermoplasticized in the extruder main body is discharged in a cylindrical shape from an extrusion port formed in a die (die and nipple) through an annular flow path in the crosshead. Usually, in order to determine the basic cross-sectional shape, the extrusion port is the part where the gap is the smallest in the annular channel, and the rubber composition (unvulcanized product) is compressed at the same time as being thermoplasticized. and the strain received at that time is maintained up to the extrusion port. Therefore, the rubber composition (unvulcanized product) is released (under atmospheric pressure) at the moment it is discharged from the extrusion port and expands, resulting in so-called die swell. Then, at the same time as the die swells, it shrinks due to cooling. In other words, when the rubber composition (unvulcanized product) discharged from the extrusion port is cylindrical, the rubber composition discharged from the extrusion port undergoes die swell (the thickness increases) at the moment it is discharged from the extrusion port. It tries to pass through the inside of the die in front of the extrusion port while shrinking due to cooling.

However, in the conventional extrusion method, since the distance (radial direction) between the die (inner peripheral surface) and the outer peripheral surface of the spun mold is approximately the same as the thickness of the rubber composition layer, the rubber composition is discharged from the extrusion port. A state in which the rubber composition (unvulcanized product) layer is in contact with the die (inner peripheral surface) and the outer peripheral surface of the spun mold without any gap in the thickness direction (Fig. 1 of Patent Document 1 , and FIG. 14 of Comparative Example 1 to be described later), passing through the inside of the die in front of the extrusion port. Then, the rubber composition (unvulcanized) layer receives shear resistance from the die wall surface (inner peripheral surface) due to the property (cohesive force) of the rubber component, and the rubber composition (unvulcanized) layer Shear stress is generated in the coated cord. This is considered to be the cause of pitch disturbance in the core wire.

Therefore, when the conventional extrusion method is applied to the production of a rubber toothed belt composed of core wires and tooth cloth in addition to the rubber composition which is the base material of the belt body, quality and productivity are improved. I found it difficult to reconcile.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a rubber toothed belt manufacturing method and a toothed belt manufacturing apparatus capable of achieving both quality and productivity.

One of the present inventions for solving the above-mentioned problems is a rubber composition having, as a base material, a plurality of tooth portions provided at predetermined intervals in the belt circumferential direction and a back portion in which cords are embedded. A method for manufacturing a toothed belt having a belt body having a plurality of tooth portions covered with a tooth cloth,
a spinning step of mounting the cylindrical tooth cloth on the outer periphery of a mold having a tooth profile formed on the cylindrical outer peripheral surface, and spinning the cord on the tooth cloth;
The thermoplastic rubber composition is discharged in a cylindrical shape onto the outer peripheral surface of the spun mold in which the cord is spun on the tooth cloth, and the outer peripheral surface is covered to be unvulcanized. a coating step to form a belt sleeve;
a vulcanization step of vulcanizing the unvulcanized belt sleeve while pressurizing it from the outer peripheral side to form the tooth portion;
In the coating step,
By continuously supplying compressed air between the outer peripheral surface of the spun mold and the rubber composition discharged in a cylindrical shape, the outer peripheral surface of the spun mold and the cylindrical rubber composition forming an annular gap between the rubber composition discharged to
When the rubber composition discharged in a cylindrical shape reaches a predetermined position on the outer peripheral surface of the spun mold, the discharge of the rubber composition is stopped and the compressed air is discharged. The annular gap is closed.

According to the above method, in the coating step, by supplying compressed air between the outer peripheral surface of the spinning mold and the rubber composition discharged in a cylindrical shape, the rubber composition is expanded into a cylindrical shape. A radial force can be applied to form an annular gap between the outer peripheral surface of the spun mold and the cylindrically discharged rubber composition. As a result, the rubber composition can be prevented from coming into contact with the core wire spun on the outer peripheral surface of the mold while the thermoplastic rubber composition is discharged in a cylindrical shape.
Furthermore, when the rubber composition discharged in a cylindrical shape reaches a predetermined position on the outer peripheral surface of the spun mold, the discharge of the rubber composition is stopped and the compressed air is discharged to close the annular gap. , the radially expanding force acting on the tubular rubber composition disappears. As a result, the diameter of the thermoplastic cylindrical rubber composition is reduced due to the contraction action caused by cooling, and the rubber composition adheres to the outer peripheral surface of the spun mold. As a result, the rubber composition discharged in a cylindrical shape is coated on the outer peripheral surface of the spun mold in a layer without generating shear stress on the core wire spun on the outer peripheral surface of the mold. will be In other words, in the covering process for forming the unvulcanized belt sleeve, the cords can be prevented from being disturbed in pitch (displacement of the cords).
In the coating step, each time the coating of the thermoplastic tubular rubber composition is completed, the tubular rubber composition is cut, and a mold with an unvulcanized belt sleeve coated with the rubber composition is formed. An unvulcanized belt sleeve having a cylindrical rubber composition coated in a layer on the outer peripheral surface of the spun mold can be continuously formed by simply replacing the spun mold with a new spun mold. Therefore, compared to the conventional method (requiring a series of complicated processes such as sheeting, cutting, winding on a mold, and jointing using rolling equipment such as calendar rolls), it is possible to save labor and is suitable for manufacturing toothed belts. Such productivity can be improved.

Further, one aspect of the present invention is that, in the coating step of the method for manufacturing the toothed belt,
Arrange the spun mold in an extruder having an annular extrusion port so that the center of the annular extrusion port is arranged on an extension line of the central axis of the mold,
Furthermore, the core wire spun in the mold and the extrusion port are arranged at a predetermined distance in the central axis direction of the mold,
The method is characterized in that the thermoplastic rubber composition is discharged in a cylindrical shape from the extrusion port, and the unvulcanized belt sleeve is formed by covering the outer peripheral surface of the spun metal mold.

As in the above method, the core wire spun in the mold and the extrusion port are arranged at a predetermined distance in the central axis direction of the mold, so that the thermoplastic rubber composition is ejected from the extrusion port. To prevent the expanded rubber composition from coming into contact with the core wire even if it swells (die swells) when it is discharged, because there is a distance between the extrusion port and the core wire. can be done (prevents the core wire spun in the mold from shifting).

Further, one aspect of the present invention is that, in the coating step of the method for manufacturing the toothed belt,
It is characterized in that when the compressed air is exhausted, the annular gap is set to a negative pressure lower than the atmospheric pressure.

According to the above method, in the coating step, when the rubber composition discharged in a cylindrical shape reaches a predetermined position on the outer peripheral surface of the spun mold, the discharge of the rubber composition is stopped and the spun rubber composition is stopped. The annular gap formed between the outer peripheral surface of the mold and the cylindrically discharged rubber composition becomes negative pressure, and the outer peripheral side of the cylindrically discharged rubber composition is kept at atmospheric pressure. become. Therefore, compared to the case where the annular gap is not under negative pressure (that is, the case where it is under atmospheric pressure), the diameter reduction due to the contraction action of the thermoplasticized cylindrical rubber composition due to cooling is performed smoothly, and the spinning Adhesion of the cylindrical rubber composition to the outer peripheral surface of the mold is improved.
In addition, the size of the annular gap formed between the outer peripheral surface of the spun mold and the rubber composition discharged in a cylindrical shape is controlled by the rubber composition coated in a layer on the outer peripheral surface of the spun mold. Since it can be set relatively large (for example, twice as large) as the thickness of the mold, the peripheral length range of the mold can be expanded compared to the case where the annular gap is not subjected to negative pressure. That is, it is possible to expand the peripheral length range of unvulcanized belt sleeves having the same thickness but different peripheral lengths. Therefore, productivity can be further improved as compared with the conventional extrusion method.

Moreover, one aspect of the present invention is the method for manufacturing the toothed belt,
The extruder is
a screw for discharging the rubber composition from the extrusion port;
A screw rotation speed detector that detects the rotation speed of the screw and transmits it as a screw rotation speed signal;
a pressure detector that detects the pressure inside the rubber composition flow path between the tip of the screw and the extrusion port and transmits it as an internal pressure detection signal;
a mold supply device that supplies the mold so that the center of the extrusion port is arranged on an extension of the central axis of the mold;
a mold supply position detector that detects the position of the mold and transmits it as a mold supply position signal;
a pressure source for supplying and discharging the compressed air;
an extrudate tip position detector that detects that the rubber composition has reached a predetermined position on the outer peripheral surface of the spun mold and transmits it as an extrudate tip position signal;
a cutting device;
a cutting detector that detects completion of cutting of the unvulcanized belt sleeve by the cutting device and transmits a cutting detection signal;
Unvulcanized belt sleeve type information that defines the specifications of the unvulcanized belt sleeve, and from the extrusion port of the rubber composition based on the rotation speed of the screw set for each of the unvulcanized belt sleeve type information Setting information for storing discharge speed information that defines the discharge speed of and reference extrudate tubular internal pressure information that defines the pressure applied to the rubber composition by the pressure source corresponding to the discharge speed information a storage unit;
The screw rotation speed signal from the screw rotation speed detector, the internal pressure detection signal from the pressure detector, the mold supply position signal from the mold supply position detector, and the extrudate tip position detector Based on at least one of the extrudate tip position signal, the reference extrudate cylindrical internal pressure information read from the setting information storage unit, and the cut detection signal from the cut detector, the mold a control unit that controls the operation of the supply device and the pressure source;
The operation of the mold supply device and the pressure source is controlled by the control unit for each of the unvulcanized belt sleeve type information.

According to the above method, it is possible to automatically control the operation of a series of mold feeders and pressure sources for each specification of the unvulcanized belt sleeve. As a result, labor saving is further advanced compared to the conventional method, and productivity is further improved.

Further, one aspect of the present invention includes a belt body made of a rubber composition as a base material and having a plurality of tooth portions provided at predetermined intervals in the circumferential direction of the belt and a back portion in which a core wire is embedded. and a toothed belt manufacturing apparatus in which the surfaces of the plurality of tooth portions are covered with a tooth cloth,
an extruder having an annular extrusion port;
a mold that is detachable from the extruder so that a tooth profile is formed on the cylindrical outer peripheral surface and the center of the annular extrusion port is arranged on the extension line of the central axis;
Compressed air can be supplied to the annular gap formed between the cylindrical rubber composition extruded from the extrusion port and the outer peripheral surface of the mold, and the compressed air can be discharged from the annular gap. and a pressure source.

According to the above configuration, by supplying compressed air from a pressure source between the outer peripheral surface of the spun mold and the rubber composition discharged in a cylindrical shape from the extrusion port, the rubber composition is formed in a cylindrical shape. An annular gap can be formed between the outer peripheral surface of the spun mold and the cylindrically discharged rubber composition by applying a force in the radially expanding direction to the object. As a result, the rubber composition can be prevented from coming into contact with the core wire spun on the outer peripheral surface of the mold while the thermoplastic rubber composition is discharged in a cylindrical shape.
Furthermore, when the rubber composition discharged in a cylindrical shape reaches a predetermined position on the outer peripheral surface of the spun mold and the discharge of the rubber composition is stopped, the compressed air is discharged from the annular gap by the pressure source, By closing the gap, it is possible to eliminate the radially expanding force acting on the tubular rubber composition. As a result, the diameter of the thermoplastic cylindrical rubber composition is reduced due to the contraction action caused by cooling, and the rubber composition adheres to the outer peripheral surface of the spun mold. As a result, the rubber composition discharged in a cylindrical shape is coated on the outer peripheral surface of the spun mold in a layer without generating shear stress on the core wire spun on the outer peripheral surface of the mold. will be In other words, when forming the unvulcanized belt sleeve, it is possible to prevent the cords from being disturbed in pitch (displacement of the cords).
In addition, every time the coating of the thermoplastic tubular rubber composition is completed, the tubular rubber composition is cut, and a mold with an unvulcanized belt sleeve coated with the rubber composition and a new spinning An unvulcanized belt sleeve having a cylindrical rubber composition coated in a layer on the outer peripheral surface of the spun mold can be continuously formed by simply replacing the mold with the already spun mold. Therefore, compared to the conventional method (requiring a series of complicated processes such as sheeting, cutting, winding on a mold, and jointing using rolling equipment such as calendar rolls), it is possible to save labor and is suitable for manufacturing toothed belts. Such productivity can be improved.

Further, one aspect of the present invention is the toothed belt manufacturing apparatus,
The mold is attached to the extruder so that the cord spun in the mold and the extrusion port are arranged at a predetermined distance in the central axis direction of the mold. is characterized by

As described above, the cord spun in the mold and the extrusion port are arranged at a predetermined distance in the direction of the center axis of the mold, so that the thermoplastic rubber composition is expelled from the extrusion port. To prevent the expanded rubber composition from coming into contact with the core wire even if it swells (die swells) when it is discharged, because there is a distance between the extrusion port and the core wire. can be done (prevents the core wire spun in the mold from shifting).

Further, one aspect of the present invention is the toothed belt manufacturing apparatus,
The pressure source is characterized in that when the compressed air is exhausted, the annular gap can be set to a negative pressure lower than the atmospheric pressure.

According to the above configuration, when the rubber composition discharged in a cylindrical shape from the extrusion port reaches a predetermined position on the outer peripheral surface of the spun mold and the discharge of the rubber composition is stopped, the spun gold The annular gap formed between the outer peripheral surface of the mold and the cylindrically discharged rubber composition becomes negative pressure, and the outer peripheral side of the cylindrically discharged rubber composition is kept at atmospheric pressure. . Therefore, compared to the case where the annular gap is not under negative pressure (that is, the case where it is under atmospheric pressure), the diameter reduction due to the contraction action of the thermoplasticized cylindrical rubber composition due to cooling is performed smoothly, and the spinning Adhesion of the cylindrical rubber composition to the outer peripheral surface of the mold is improved.
In addition, the size of the annular gap formed between the outer peripheral surface of the spun mold and the rubber composition discharged in a cylindrical shape is controlled by the rubber composition coated in a layer on the outer peripheral surface of the spun mold. Since it can be set relatively large (for example, twice as large) as the thickness of the mold, the peripheral length range of the mold can be expanded compared to the case where the annular gap is not subjected to negative pressure. That is, it is possible to expand the peripheral length range of unvulcanized belt sleeves having the same thickness but different peripheral lengths. Therefore, productivity can be further improved as compared with the conventional extrusion method.

Further, one aspect of the present invention is the toothed belt manufacturing apparatus,
The extruder is
a screw for discharging the rubber composition from the extrusion port;
A screw rotation speed detector that detects the rotation speed of the screw and transmits it as a screw rotation speed signal;
a pressure detector that detects the pressure inside the rubber composition flow path between the tip of the screw and the extrusion port and transmits it as an internal pressure detection signal;
a mold supply device that supplies the mold so that the center of the extrusion port is arranged on an extension of the central axis of the mold;
a mold supply position detector that detects the position of the mold and transmits it as a mold supply position signal;
an extrudate tip position detector that detects that the rubber composition has reached a predetermined position on the outer peripheral surface of the spun mold and transmits it as an extrudate tip position signal;
a cutting device;
a cutting detector that detects completion of cutting of the unvulcanized belt sleeve by the cutting device and transmits a cutting detection signal;
Unvulcanized belt sleeve type information that defines the specifications of the unvulcanized belt sleeve, and from the extrusion port of the rubber composition based on the rotation speed of the screw set for each of the unvulcanized belt sleeve type information Setting information for storing discharge speed information that defines the discharge speed of and reference extrudate tubular internal pressure information that defines the pressure applied to the rubber composition by the pressure source corresponding to the discharge speed information a storage unit;
The screw rotation speed signal from the screw rotation speed detector, the internal pressure detection signal from the pressure detector, the mold supply position signal from the mold supply position detector, and the extrudate tip position detector Based on at least one of the extrudate tip position signal, the reference extrudate cylindrical internal pressure information read from the setting information storage unit, and the cut detection signal from the cut detector, the mold a control unit that controls the operation of the supply device and the pressure source;
The operation of the mold supply device and the pressure source is controlled by the control unit for each of the unvulcanized belt sleeve type information.

According to the above configuration, it is possible to automatically control a series of operations of the mold supply device and the pressure source for each specification of the unvulcanized belt sleeve. As a result, labor saving is further advanced compared to the conventional method, and productivity is further improved.

It is possible to provide a rubber toothed belt manufacturing method and a toothed belt manufacturing apparatus capable of achieving both quality and productivity.

It is a cross-sectional view of a toothed belt to be manufactured. It is explanatory drawing of the metal mold|die which concerns on this embodiment. It is explanatory drawing of the extruder which concerns on this embodiment. FIG. 2 is an enlarged view of a main part showing a compressed air supply route according to the embodiment; It is a front view of a nipple according to the present embodiment. It is a lineblock diagram of an extruder and a control device concerning this embodiment. FIG. 4 is an explanatory diagram of continuous operations performed in the coating process of the present embodiment; FIG. 4 is an explanatory diagram of continuous operations performed in the coating process of the present embodiment; It is an enlarged view around the extrusion port of the extruder according to the present embodiment (Examples 1 and 2). It is an enlarged view around the extrusion port of the extruder according to the present embodiment (Examples 1 and 2). It is an enlarged view around the extrusion mouth of the extruder which concerns on this embodiment (Example 3). It is an enlarged view around the extrusion mouth of the extruder which concerns on this embodiment (Example 3). 1 is a schematic diagram of an extruder according to Comparative Example 1. FIG. 2 is an enlarged view around an extrusion port of an extruder according to Comparative Example 1. FIG.

(embodiment)
Hereinafter, a toothed belt manufacturing method and a toothed belt manufacturing apparatus according to the present invention will be described with reference to the drawings.

The toothed belt 1 manufactured by the manufacturing method and manufacturing apparatus of the present embodiment is an endless, ring-shaped power transmission belt used for synchronous transmission of industrial machinery. For example, the toothed belt 1 is used by being wound between a driving pulley and a driven pulley having teeth that mesh with the teeth of the toothed belt 1 .

(Structure of toothed belt 1)
As shown in the cross-sectional view of the toothed belt 1 in FIG. 1, the toothed belt 1 includes a plurality of toothed portions 2 provided at predetermined intervals in the circumferential direction of the belt, and a back portion 4 in which a core wire 3 is embedded. and a tooth cloth 6 covering the surfaces of the plurality of tooth portions 2 .

Rubber compositions constituting the teeth 2 and the back 4 include natural rubber (NR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), chlorosulfonated polyethylene (CSM), alkylated chlorosulfonated polyethylene ( ACSM), nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), hydrogenated nitrile rubber compounded with unsaturated carboxylic acid metal salt, ethylene propylene diene monomer (EPDM), butyl rubber (IIR), etc. can be used alone or in blends. Alternatively, it is also possible to use polyurethane rubber in addition to these rubbers. Among them, in the case of the toothed belt 1, it is desirable to use rubber with improved heat aging resistance, and in the case of hydrogenated nitrile rubber, the hydrogenation rate is 80% or more, and heat resistance and ozone resistance are exhibited. 90% or more is more preferable in order to do so. A hydrogenated nitrile rubber having a hydrogenation rate of less than 80% may have extremely low heat resistance and ozone resistance.

The rubber composition constituting the tooth portion 2 and the back portion 4 contains a reinforcing agent such as carbon black, a filler, a softening agent, an anti-aging agent, a vulcanizing aid, sulfur or an organic peroxide. A vulcanizing agent or the like is added and mixed. In addition, when an organic peroxide is blended as a cross-linking agent, in order to secure a predetermined modulus (tensile modulus) and breaking elongation, 0.2 to 0.2 parts of the organic peroxide is added to 100 parts by mass of the polymer component. It is necessary to mix 10 parts by mass and crosslink. Organic peroxides are not particularly limited. In addition to such organic peroxides, metal oxides, sulfur compounds, oxime nitroso compounds, monomers, and polymers generally used as co-crosslinking agents may be added in appropriate amounts.

In the present embodiment, the rubber composition (unvulcanized) constituting the tooth portion 2 and the back portion 4 is a rubber composition containing EPDM as a rubber component (rubber component: 100 parts by mass of EPDM, compounding agent: 5 parts by mass of zinc white , vulcanization accelerator 1.5 parts by mass, sulfur 1 part by mass, antioxidant 2 parts by mass, carbon black 50 parts by mass, oil 8 parts by mass).

As the core wire 3, a twisted cord with low elongation and high strength such as polyparaphenylenebenzobisoxazole fiber (PBO fiber), aramid fiber, glass fiber, carbon fiber, or the like is used. In the case of the glass cord, the composition may be either E glass or S glass (high strength glass), and the thickness of the filament, the number of converging filaments, and the number of strands are not limited. Moreover, there are no restrictions on the sizing agent, RFL, overcoat agent, and the like used as an adhesion treatment agent and a protective material for the glass filaments during bending.

The cord 3 is subjected to adhesion treatment for the purpose of improving adhesion to the rubber composition forming the spine 4 . As such an adhesion treatment, the fibers are generally immersed in a resorcin-formalin-latex (RFL) solution and then dried by heating to form a uniform adhesion layer on the surface. However, without being limited to this, there is also a method of pretreating with an epoxy or isocyanate compound and then treating with the RFL liquid.

In this embodiment, as the core wire 3, about 600 glass fiber filaments with a wire diameter of about 9 μm are bundled to form a strand, and this strand is RFL liquid (110 parts by weight of resorcin, formalin (37%) by weight, caustic soda 1 part by mass, VP latex 4,000 parts by mass, SBR latex 1,100 parts by mass, water 5,500 parts by mass), dried at 200 ° C for 2 minutes, twist number of 16.0 turns / 10 cm A cord with a diameter of about 0.3 mm is used.

The tooth cloth 6 is a base cloth selected from woven fabrics, knitted fabrics, non-woven fabrics, and the like. As the fiber material constituting the base fabric, known materials can be used, and examples include natural fibers such as cotton and hemp, inorganic fibers such as metal fibers and glass fibers, and polyamide, polyester, polyethylene, polyurethane, polystyrene, and polystyrene. Organic fibers such as fluoroethylene, polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid can be mentioned, and it is preferable to use fabrics obtained by weaving them in plain weave, twill weave, satin weave, or the like.

The form of the fiber is not limited to spun yarn, multifilament yarn, monofilament yarn, etc. However, if the monofilament yarn is used as the constituent yarn to increase unevenness due to the crossing of the warp and weft yarns to reduce the surface friction coefficient, Shows good wear resistance and tooth chipping resistance. In addition, lowering the weave density and using fibers with a large diameter are also effective means for lowering the surface friction coefficient. Further, in the case of the manufacturing method of the present embodiment, stretchability is required in the weft direction of the base fabric due to the press-fitting method. For this reason, it is preferable to use crimped 6 nylon, 66 nylon, or composite yarn twisted with urethane elastic yarn for the weft yarn along the circumferential direction of the belt body 5 . Further, when monofilament yarn is used for the base fabric, it is desirable to use it for the warp so as not to affect the stretchability in the weft direction.

In addition, the base fabric is immersed in a resorcinol-formalin-latex solution (RFL solution) according to a known technique, and then friction is applied by rubbing unvulcanized rubber against the base fabric, or after immersion in the RFL solution, the rubber is dissolved in a solvent. immersion treatment in a soaking solution. Alternatively, the bonding process may be performed using only the RFL liquid.

The RFL liquid is a mixture of an initial condensate of resorcinol and formalin and rubber latex, and the molar ratio of resorcinol to formalin is preferably 1:0.5 to 3 to increase adhesion. The initial condensate of resorcin and formalin is mixed with latex so that the resin content is 10 to 100 parts by weight per 100 parts by weight of the rubber content of the latex, and the total solid concentration is 5 to 40 parts. % concentration. The RFL liquid may be appropriately mixed with a carbon black liquid to dye the treated fabric black, or a known surfactant may be added in an amount of 0.1 to 5.0% by weight. Examples of the latex include styrene-butadiene-vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, epichlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, EPDM and the like. latex.

In this embodiment, as the base fabric of the tooth cloth 6, 210 d/1 nylon filament yarn is used for the warp, and 40 d/5 woolly nylon yarn is used for the weft. A 2/2 twill canvas of 100 wefts/3 cm) was woven. Rubber paste obtained by dissolving the above unvulcanized rubber composition in methyl ethyl ketone at a predetermined ratio after the canvas is shrunk to about 1/2 of the width at the time of weaving by applying vibrations in water after weaving. A treated canvas having a thickness of 0.9 mm is used as the tooth cloth 6 after being immersed in and dried, and vulcanized at 153° C. for 30 minutes.

Further, in the present embodiment, the toothed belt 1 has a belt shape S3M (toothed portion 2 has 70 teeth, pitch between teeth is 3 mm) and belt circumferential length is 210 mm. The unvulcanized belt sleeve has a diameter (outer diameter) of about 70 mm and an effective surface length of 400 mm to ensure productivity. For example, 40 toothed belts 1 having a belt width of 10 mm are obtained from this unvulcanized belt sleeve.

(Manufacturing apparatus 100)
Next, a mold 10, an extruder 20, a pressure source 23 (pressurizing device 231, a negative pressure device 232), a mold feeding device 24, and a manufacturing apparatus 100 for manufacturing the toothed belt 1 shown in FIG. The cutting device 25 and the control device 30 will be described.

(Mold 10)
The mold 10, as shown in FIG. 2, has a body portion 11 having a tooth profile (not shown) in which concave portions and convex portions are alternately provided on the outer peripheral surface of a cylindrical shape at predetermined intervals in the circumferential direction; A toothed mold having a front gripping portion 12 provided at the front end of the body portion 11 and a rear gripping portion 13 provided at the rear end of the body portion 11, the mold being detachable from the extruder 20. It is The surface length (longitudinal length) of the body portion 11 is set longer (for example, 450 mm) than the sleeve length (surface length) to be formed (for example, the effective surface length is 400 mm). The front gripping portion 12 is a portion gripped by a chuck portion 241 of a mold feeding device 24, which will be described later. The rear grip part 13 is a part inserted into the hole 229 of the nipple 224 so that the center axis of the mold 10 is coaxial with the center axis C of the extruder 20 (see FIG. 3), and , which is to be inserted into a receiving portion (vertically upward) of a mold conveying device 26 (see FIG. 6) that conveys the mold 10 through a spinning process, a coating process, and a vulcanizing process, which will be described later.

In addition, a cylindrical cavity 111 is provided inside the body portion 11, and a communication passage 121 formed inside the front grip portion 12 and a communication passage 131 formed inside the rear grip portion 13 are connected to each other. It is connected. A communication port 122 provided on the opposite side of the cavity 111 in the communication path 121 has a funnel shape. A communication path 242 provided inside a chuck portion 241 to be described later is inserted into the communication path 121 through the communication port 122, so that the communication path 242 and the cavity 111 communicate with each other. A communication port 132 provided on the opposite side of the cavity 111 in the communication passage 131 has a funnel shape. Engage member 230 .

An annular guide member 112 is attached to the end of the body portion 11 on the rear side grip portion 13 side. The outer peripheral surface 112a of the guide member 112 has a tapered shape as shown in FIG. The diameter (maximum diameter portion) of the tapered outer peripheral surface 112a of the guide member 112 is the outer diameter of the spun mold 10 in which the core wire 3 is spun on the outer peripheral surface of the body portion 11 of the mold 10. is formed to be the same as or slightly larger than (in the present embodiment, it is formed to be slightly larger). In addition, on the outer peripheral surface 112a of the guide member 112, a large number of concave grooves 112b extending in the longitudinal direction (front-rear direction) of the mold 10 are formed with arbitrary shapes and depths at equal pitches in the circumferential direction. there is The bottom portion 112c of the cut groove 112b intersects the tapered outer peripheral surface 112a of the guide member 112 at the end portion of the guide member 112 on the rear side grip portion 13 side. A recessed groove portion 112d extending in the circumferential direction is provided at the end portion of the guide member 112 on the front grip portion 12 side. By cutting (push-cutting) the layer of the rubber composition while pressing the cutting edge of the cutting device 25 against the concave groove 112d, the cutting operation by the cutting device 25 can be reliably performed (accuracy of the cut location). , leaving no uncut points).

The body portion 11 includes a guide having a tapered surface formed at different positions and angles depending on the type of the mold 10 (those with different peripheral lengths) and the dimensions of various parts around the extrusion port 228 of the extruder 20, which will be described later. A member 112 is attachable.

In this embodiment, the number of teeth (the number of convex portions) is 70, the pitch between the tooth profiles is 3 mm, the peripheral length is 210 mm, and the face length (longitudinal length) is 450 mm. tooth profile (S3M) is formed. Further, the front gripping portion 12 and the rear gripping portion 13 are protruded from both ends of the mold 10 and have a diameter smaller than that of the body portion 11 .

(Extruder 20)
The extruder 20 is composed of a main body 21 and a straight head 22, as shown in FIG. The extruder 20 also has a pressure source 23 (a pressure device 231 and a negative pressure device 232 ), a mold supply device 24 and a cutting device 25 .

The main body 21 is composed of a cylinder 211 having an internal space, a screw 212, a drive motor 213 (see FIG. 6), and the like. In this embodiment, the screw 212 uses a rubber screw with a screw diameter of 75 mm.

The straight head 22 is an extruder head that discharges the rubber composition (corresponding to extrudate) in the same direction (substantially horizontal direction) as the central axis C of the cylinder 211 of the main body 21 . The straight head 22, as shown in FIG. to the head body 221 with a nut 226 .

Inside the head body 221, there is provided a funnel-shaped internal space that expands forward (in the ejection direction). The internal space of the head body 221 communicates with the internal space of the cylinder 211 by connecting the head body 221 to the main body 21 .

The support member 222 connects the outer ring portion 222a that contacts the inner peripheral surface of the head body 221, the inner ring portion 222b that contacts the outer peripheral surface of the nipple 224, and the outer ring portion 222a and the inner ring portion 222b. A connecting portion 222c for forming a hollow portion 222d (rubber composition flow path) between the outer ring portion 222a and the inner ring portion 222b. The connecting portions 222c are normally 3 to 12 equally divided in the circumferential direction in consideration of the strength against pressure. In this embodiment, as shown in FIG. 3, eight connecting portions 222c are provided.

As shown in FIG. 3, the mouthpiece 223 includes a nipple 224 arranged coaxially with the central axis C of the extruder 20 (head body 221), and a cylindrical die arranged forward of the nipple 224. 225 and has an annular channel 227 and an annular extrusion port 228 defined by the shape between (the outer peripheral surface of) the nipple 224 and the die 225 (the inner peripheral surface). That is, the extruder 20 has an extrusion port 228 having an annular structure for discharging the rubber composition.

The nipple 224 has a substantially conical convex portion (a portion fitted into the inner annular portion 222b) whose tip is directed rearward on the center axis C and a substantially cylindrical body portion (a portion defining the annular flow path 227). is doing. The nipple 224 is provided on the inner peripheral side of the annular flow path 227 extending from the hollow portion 222 d of the support member 222 to the extrusion port 228 . The nipple 224 is detachably fixed to the head body 221 via the support member 222 . Inside the nipple 224, there is provided a hole 229 into which the rear grip portion 13 of the mold 10 is inserted. A convex member 230 having a convex portion is incorporated. As shown in FIG. 4 , the taper angle (apex angle) of the convex portion of the convex member 230 is set equal to the taper angle of the funnel-shaped communication port 132 of the rear grip portion 13 of the mold 10 . In addition, as shown in FIG. 5, on the conical surface of the convex member 230, a large number of concave grooves 230A extending from the top to the plane of the base with arbitrary width and depth are formed over the entire circumferential direction (for example, 10) is formed.

The die 225 has a cylindrical shape, and the inner peripheral surface of the die 225 has a funnel shape that is inclined from the rear to the front. The die 225 is provided on the outer peripheral side of the annular flow path 227 leading to the extrusion port 228 . The die 225 is detachably fixed to the head body 221 by screwing with a nut 226 or the like. 4 and 9, the die 225 has a shape that protrudes forward from the nipple 224. As shown in FIGS. As a result, the extrusion port 228 defined by the shape between the nipple 224 and the die 225 has an annular structure (perfect circle) oriented in the central axis C direction. In this embodiment, the extrusion port 228 is oriented in the direction of the central axis C, but the end of the nipple 224 and the end of the die 225 that define the extrusion port 228 are aligned in the direction of the central axis C. As a result, the ejection port 228 may face forward (discharge direction).

Note that the die 225, including the nut 226, must not be deformed or dropped under an internal pressure of 50 MPa, for example. For this reason, the portion of the die 225 that protrudes forward from the nipple 224 has a protruding length (for example, about 2 mm) in consideration of the safety factor in pressure resistance, although it depends on the strength of the material (for example, S45C). .

In addition, as shown in FIG. 9, the rear side grip portion 13 of the mold 10 is inserted into the hole 229 of the nipple 224 of the extruder 20 (the spun mold 10 is positioned at the central axis of the mold 10). The center of the annular extrusion port 228 is arranged on the extension line), the extrusion port 228 is the core wire 3 spun on the body portion 11 of the mold 10 (most toward the rear grip portion 13 side). It is formed at a position at a predetermined distance Cs in the direction of the central axis of the mold 10 with respect to the spun core wire 3).

The preferred range for the distance Cs is the circumference of the unvulcanized belt sleeve to be formed, the type of rubber composition to be coated (particularly, dynamic viscosity characteristics), the thickness of the rubber composition to be coated, and the outside of the mold 10. diameter, surface length of the body portion 11, outer diameter of the die 10 after spinning (including the thickness of the tooth cloth 6 and the core wire 3), cross-sectional shape around the extrusion port 228, annular gap during ejection of the rubber composition It varies depending on various design items such as the pressure (set value) of the compressed air supplied to 14, and the discharge speed of the rubber composition corresponding to the extrusion operating conditions (screw rotation speed, temperature control temperature of each part, etc.). . As a guideline, for example, under the setting conditions shown in Examples 1 to 3 (described later), the thickness is approximately 1 to 50 times the thickness of the rubber composition to be coated, and as a guideline, about 15 times (thickness of the rubber composition If the height T is 1 mm, it may be set to about 15 mm). When the distance Cs is less than 1 times (less than 1 mm if T is 1 mm), the distance Cd in the radial direction of the die 10 between the extrusion port 228 and the outer peripheral surface of the spun die 10 is equal to the extrusion port When set to the same dimension as the thickness of the rubber composition discharged from 228 (corresponding to the distance Cd in Example 3 described later), the outer peripheral surface of the spun mold 10 and the discharged cylindrical rubber composition Compressed air is supplied to the annular gap 14 formed between and when the rubber composition expands (increases in diameter), the rubber composition is spun on the outer peripheral surface of the spun mold 10. It comes into contact with the wire 3 (the core wire 3 spun to the side of the gripping portion 13 on the rearmost side of the body portion 11) (there is a risk of deviation of the core wire 3). On the other hand, if the distance Cs exceeds 50 times (50 mm if T is 1 mm), the distance Cs becomes too long, resulting in a decrease in productivity.

The flow path design from the inner space of the cylinder 211 to the extrusion port 228 via the inner space of the head body 221 of the straight head 22, the hollow portion 222d of the support member 222, and the annular flow path 227 includes an annular flow path. Adjust the flow of the rubber composition inside the flow path from the cylinder 211 to the extrusion port 228 so that the rubber composition flows uniformly in the circumferential direction in the inside 227 (between the nipple 224 and the die 225). A flow guide or the like (conventional technology) may be provided.

In the extruder 20 of the present embodiment, the straight head 22 moves the mold 10 from the front to the rear in the mold supply direction, and the rubber composition is discharged from the extrusion port 228 to the outer peripheral surface of the mold 10. It is connected to the main body 21 so that the discharge direction of the cartridge is horizontal. However, not limited to this structure, the extruder 20 has the extruder 20 shown in FIG. The main body 21 is arranged so that the mold supply direction in which the rubber composition 10 is moved upward from the bottom and the discharge direction in which the rubber composition is discharged from the extrusion port 228 to the outer peripheral surface of the mold 10 are in the vertical direction (gravitational direction). A connected configuration is also possible. In this case, the influence of gravity on the cylindrical rubber composition discharged from the extrusion port 228 can be made uniform, and biased deformation of the rubber composition due to gravity can be prevented.

In addition, the head body 221 is provided with an alignment bolt (not shown) in order to deal with unevenness in the thickness (actual value) of the layer of the rubber composition discharged from the extrusion port 228 of the mouthpiece 223. . This alignment work is carried out by pushing and pulling an alignment bolt whose tip surface is in contact with the outer peripheral surface of the die 225 to move the die 225 in the radial direction while keeping the nipple 224 fixed (alignment work).

In this embodiment, as shown in FIG. 9, the target value of the gap size (Co) of the extrusion port 228 is 0.5 mm, and the thickness (T) of the discharged rubber composition layer is 1 mm. . Here, the thickness (T) of the layer of the discharged rubber composition means that the die swells (the thickness increases) at the moment of being discharged from the extrusion port 228, and the diameter is reduced by contraction due to standing cooling. thickness. The die swell (T/Co=1/0.5) at this time is two. Also, the distance Cs between the extrusion port 228 and the cord 3 spun on the body portion 11 of the mold 10 (the cord 3 spun on the rearmost gripping portion 13 side) is 13 mm.

(Pressure source 23: pressure device 231)
A pressure device 231 (hot air generator: not shown) is connected to a connection port 245 of a communication passage 242 provided in the chuck portion 241 (see FIG. 3). As a result, as shown in FIGS. 3, 4, and 9, the pressurizing device 231 and the annular gap 14 (between the outer peripheral surface of the spun mold 10 and the ejected cylindrical rubber composition) are formed. A switching valve provided between the pressurizing device 231 and the connection port 245 (the path on the pressurizing device 231 side, the path on the negative pressure device 232 side: not shown), the connection port of the chuck part 241 245, communication path 242 of chuck part 241, communication path 121 of front grip part 12, cavity 111 of body part 11, communication path 131 of rear grip part 13, cut groove 230A of projecting member 230, mold 10 and nipple 224 4) and the supply path formed by the cut groove 112b of the guide member 112, and both are in a state of communication. Although not shown, the switch valve connected to the pressurizing device 231 and the negative pressure device 232 described later allows a path leading to the connection port 245 to be routed between the pressurizing device 231 and the negative pressure device 232. It is switchable.

Then, compressed air is supplied to the annular gap 14 through the pressure regulator provided in the pressurizing device 231 to pressurize the annular gap 14 (at a pressure higher than the atmospheric pressure, for example, within the range of 0.02 to 0.1 MPa). )can do. In addition, the ambient temperature of the compressed air continuously supplied to the annular gap 14 is set to room temperature (approximately 23° C.) or higher than the room temperature (approximately 23° C.) by the electric heater and temperature regulator provided in the pressurizing device 231. The temperature (for example, about 40 to 60° C.) can be set. The compressed air also receives radiant heat from the nipple 224 by passing through the air passage 133 formed between the mold 10 and the nipple 224 whose temperature is controlled to about 90° C., and room temperature (about 23 ° C.) (for example, about 40 to 60° C.).

As a result, after the rubber composition is discharged from the extrusion port 228, the front end of the discharged rubber composition is the spun core wire closest to the front grip part 12 side of the body part 11 of the spun mold 10. 3, by continuously supplying compressed air between the outer peripheral surface of the spun mold 10 and the discharged cylindrical rubber composition, the spun mold 10 While the annular gap 14 is formed between the outer peripheral surface and the discharged cylindrical rubber composition, even if the rubber composition is allowed to cool excessively and then the compressed air is discharged, further It is possible to prevent the annular gap 14 from closing due to insufficient contraction due to standing cooling.

(Pressure source 23: Negative pressure device 232)
A negative pressure device 232 (vacuum negative pressure device: not shown) is connected to a connection port 245 of a communication passage 242 provided in the chuck portion 241 (see FIG. 3). Specifically, the suction device (vacuum pump: not shown) of the negative pressure device 232 and the annular gap 14 are connected via the compressed air supply path (see FIG. 4 etc.) shown in the description of the pressurizing device 231. They are connected and both are in a state of communication. By switching the piping path to the negative pressure device 232 side by means of a switching valve connected to the pressure device 231 and the negative pressure device 232, the compressed air in the annular gap 14 is shown in FIG. Compressed air passes through the shown supply path in the direction opposite to the supply direction, is quickly discharged to the outside, and the annular gap 14 can be set to a negative pressure (air pressure lower than atmospheric pressure).

(Mold supply device 24)
The die feeder 24 is attached to the extruder 20 and serves to feed the rear gripper 13 of the die 10 to the hole 229 provided inside the nipple 224 at any time by mechanical control. Specifically, the mold supply device 24 includes a chuck portion 241 capable of detachably gripping the front gripping portion 12 of the mold 10, and an extruder 20 on an extension line of the central axis C of the head body 221 as shown in FIG. A mold supply drive unit 243 that linearly moves a chuck unit 241 that grips the mold 10 between the front standby position 1 shown in FIG. and a front standby position 2 (see FIG. 6). The chuck part 241 is a three-jaw chuck. The mold supply drive unit 243 (see FIG. 6) is composed of a drive motor (servo motor, amplifier, electric cylinder), a bracket, and the like. Further, the mold turning drive section 244 (see FIG. 6) is composed of a drive motor (servo motor, amplifier), a bracket, and the like.

(Cutting device 25)
The cutting device 25 cuts (push-cuts) the annular rubber composition discharged above the concave groove portion 112d provided in the guide member 112 of the mold 10 from above the annular rubber composition toward the concave groove portion 112d. This device is externally mounted on the outer circumference of the concave groove portion 112d (see FIG. 10). In this embodiment, while pressing the cutting edge of a blade (for example, a round blade) against the annular rubber composition discharged above the concave groove portion 112d, the blade is pushed to the bottom of the concave groove portion 112d, and in that state, the blade is cut. It is made to cut (push off) the layer of the rubber composition by making one turn.

(control device 30)
The control device 30 is a device (computer) that automatically controls the mold 10, the extruder 20, and mechanisms associated therewith. The control device 30 includes a setting information storage section 31 and a control section 32, as shown in FIG.

The control device 30 is connected (wirelessly or wired) to detectors that detect various signals (information). For example, a screw rotation speed detector 301 that detects the rotation speed of the screw 212 of the extruder 20 (the rotation speed per unit time of the drive motor) and transmits it as a screw rotation speed signal, the tip of the screw 212 and the extrusion port 228 A pressure sensor 302 that detects the pressure inside the flow path of the rubber composition between and transmits it as an internal pressure detection signal, detects the relative position of the mold 10 to the extruder 20 (supply speed of the mold 10) Then, a mold supply position detector 303 (a rotary encoder built in a servo motor, an amplifier, etc.) that transmits as a mold supply position signal, the front end of the discharged rubber composition is the body part of the spun mold 10 11, an extrudate tip position detector 304 that detects reaching the vicinity of the spun core wire 3 on the side of the most front gripping part 12 and transmits it as an extrudate tip position signal, an unvulcanized belt sleeve by the cutting device 25 and a disconnection detector 305 that detects the end of disconnection and transmits a disconnection detection signal. As the extrudate tip position detector 304, a known detector can be used, for example, a detector utilizing transmission of laser light can be mentioned.

The setting information storage unit 31 stores, as known information in advance, unvulcanized belt sleeve type information (type of rubber composition as a base material, unvulcanized belt sleeve to be formed) that defines specifications of the unvulcanized belt sleeve to be produced. , the thickness of the rubber composition to be coated, the outer diameter of the mold 10, the outer diameter of the mold 10 after spinning, the type of the mold 10, the type of the mouthpiece 223, etc.), this Ejection speed information that determines the ejection speed of the rubber composition from the extrusion port 228 based on the rotation speed of the screw 212 (the ejection speed corresponding to the rotation speed of the screw 212 is stored), which is set for each vulcanized belt sleeve type information. ), and reference extrudate tubular internal pressure information (which should be adjusted based on the number of revolutions of the screw 212 (the pressurizing force to the annular gap 14 is stored).

The control unit 32 receives a screw rotation speed signal from the screw rotation speed detector 301, an internal pressure detection signal from the pressure detector 302, a mold supply position signal from the mold supply position detector 303, and an extrudate tip position detector. At least the extrudate tip position signal from 304, the reference extrudate cylindrical internal pressure information corresponding to the unvulcanized belt sleeve type information read from the setting information storage unit 31, and the cut detection signal from the cut detector 305 Based on one, the opening and closing operation of the chuck part 241 of the mold supply device 24, the supply / stop operation of the mold 10 by rotational speed control of the drive motor of the mold supply drive unit 243 (including adjustment of the supply speed), Rotating operation of the mold 10 by controlling the rotational speed of the drive motor of the mold turning driving unit 244 (including adjustment of the turning speed), rotating and stopping operation of the screw 212 by controlling the rotational speed of the drive motor 213 (rotating speed of the screw 212) adjustment), start/stop operation of the pressurizing device 231 (including adjustment of the internal pressure), start/stop operation of the suction device of the negative pressure device 232 (including adjustment of the internal pressure), and unvulcanized belt sleeve ( At least one of a series of feed operations of the mold 10 including the cutting operation of the rubber composition layer) is controlled.

Furthermore, the control device 30 of the present embodiment measures the outer diameter of the unvulcanized belt sleeve coated on the outer peripheral surface of the mold 10, and transmits a sleeve outer diameter measurement signal 306 (front and back direction). 3 locations). As the sleeve outer diameter measuring device 306, a known device can be used, for example, a measuring device using transmission of laser light can be mentioned.

Then, the control unit 32 receives the sleeve outer diameter measurement signal from the sleeve outer diameter measuring device 306 and the unvulcanized belt sleeve type information read out from the setting information storage unit 31 (outer diameter of the mold 10, metal after spinning). Based on the actual value of the thickness of the coated rubber composition calculated based on the outer diameter (target value) of the mold 10, the rotational speed of the drive motor 213 is controlled (finely adjusted), and the rotation of the screw 212 (proportional to the amount of rubber composition discharged from the extrusion port 228) is fed back.

In this case, the actual value of the thickness of the rubber composition layer to be coated can be converged to the target value at any time, so the accuracy of the thickness of the rubber composition layer to be coated can be improved compared to the case where feedback control is not performed. An unvulcanized belt sleeve can be obtained continuously.

(Manufacturing process of toothed belt 1)
(1) The cylindrical tooth cloth 6 is put on the body portion 11 of the mold 10 (having 70 teeth on the outer peripheral surface). The cylindrical tooth cloth 6 is covered so that the weft direction is aligned with the circumferential direction of the body portion 11 . As a result, the warp threads of the tooth cloth 6 of the toothed belt 1 to be produced are arranged along the width direction of the toothed belt 1 .

(2) Using a spinning device, the core wire 3 made of fiber cord is helically wound (spinning) on the tooth cloth 6 covered on the body portion 11, and the spun metal mold 10 (the tooth cloth on the body portion 11 is spun). 6 and the mold 10 coated with the core wire 3 are obtained (spinning process).

(3) For the rubber composition (unvulcanized material) that serves as the base material for the tooth portions 2 and the back portion 4 of the belt body 5 of the toothed belt 1, after the raw materials such as polymers and compounding agents are put into a kneader and kneaded. , into a ribbon shape by a slitter and supplied to the cylinder 211 of the extruder 20 . The temperature of the extruder 20 is raised to a predetermined temperature in advance using a hot water circulation type temperature control device. For example, the screw 212 and the cylinder 211 are heated to 80°C, and the straight head 22 (including the mouthpiece 223) is heated to 90°C. As a result, the thermoplastic rubber composition is supplied to the interior of the channel between the cylinder 211 and the extrusion port 228 .

In addition, as shown in FIG. 3, the straight head 22 has a mold supply direction in which the mold 10 is moved from the front to the rear, and a discharge direction in which the rubber composition is discharged from the extrusion port 228 to the outer peripheral surface of the mold 10. It is connected to the main body 21 so as to be in the direction (horizontal direction).

(4) With the chuck portion 241 of the mold feeding device 24 gripping the front gripping portion 12 of the spun mold 10, the mold 10 is supplied in the mold feeding direction, and the rear gripping portion 13 is moved to the extruder. 20 into the hole 229 of the nipple 224 . That is, the mold supply device 24 supplies the spun mold 10 so that the center of the extrusion port 228 is arranged on the extension of the central axis of the mold 10 . As a result, the communication port 132 of the rear grip portion 13 is engaged with the convex member 230 incorporated in the hole 229 of the nipple 224 .

After that, the drive motor 213 rotates the screw 212 to eject the thermoplasticized tubular rubber composition from the extrusion port 228 . At this time, the pressurizing device 231 (hot air generator) is activated, and the front end of the cylindrical rubber composition discharged from the extrusion port 228 is gripped on the frontmost side of the body portion 11 of the spun mold 10. Until reaching the vicinity of the spun core wire 3 on the part 12 side, the compressed air supplied through the supply route shown in FIG. An annular gap 14 is formed between the outer peripheral surface of the spun mold 10 and the ejected cylindrical rubber composition by continuously supplying it to the rubber composition.

Here, since the diameter (maximum diameter portion) of the tapered outer peripheral surface 112a of the guide member 112 of the mold 10 is formed slightly larger than the outer diameter of the spun mold 10, the extrusion port 228 It is possible to prevent the rubber composition from coming into contact with the outer peripheral surface (especially the core wire 3) of the spun mold 10 during discharge of the rubber composition from the mold.

In addition, according to the cut groove 112b provided on the outer peripheral surface 112a of the guide member 112, during the discharge of the rubber composition from the extrusion port 228, the rubber composition rotates the supplied compressed air flow (wind pressure). It can be efficiently received near the outer peripheral surface (core wire 3) of the finished mold 10 and at the radially outermost position. Therefore, it is possible to prevent the rubber composition from coming into contact with the outer peripheral surface (core wire 3) of the spun mold 10 during discharge of the rubber composition. Further, when the compressed air in the annular gap 14 is discharged after the discharge of the rubber composition is stopped, the rubber composition is the first to come into close contact with the guide member 112, thereby blocking the air escape route to the outside. It is possible to prevent the annular gap 14 between the inner peripheral surface of the rubber composition and the outer peripheral surface of the spun mold 10 from being blocked.

Then, when the front end of the cylindrical rubber composition discharged from the extrusion port 228 reaches the vicinity of the core wire 3 that has been spun closest to the front gripping portion 12 side of the body portion 11 of the spun mold 10, the rubber The discharge of the composition is stopped (the screw 212 is stopped), the suction device (vacuum pump) of the negative pressure device 232 is started, and the switching valve switches the piping route from the pressure device 231 side to the negative pressure device 232 side. As a result, the compressed air in the annular gap 14 passes through the supply path shown in FIG. ) so that the annular gap 14 is closed. In this way, the thermoplastic rubber composition is discharged from the extrusion port 228, and the outer peripheral surface of the mold 10 in which the core wire 3 is spun on the tooth cloth 6 is coated with the rubber composition in a layer. An unvulcanized belt sleeve is formed (coating step).

In the above-described covering step, the mold 10 has a A predetermined distance Cs is provided in the central axis direction (see FIG. 9). As a result, with respect to the discharge direction of the rubber composition from the extrusion port 228, both (the rubber composition and the spun mold 10) in a relative movement relationship can be kept out of contact.

It should be noted that, as described above, a preferable range for the distance Cs cannot be uniquely determined. Even if the distance Cd in the radial direction of the mold 10 between the extrusion port 228 and the outer peripheral surface of the spun mold 10 is set to be larger than the thickness of the rubber composition to be discharged, Even if the thickness is set to be equal to or less than the thickness of the rubber composition, it is possible to keep the rubber composition and the spun mold 10 out of contact due to the balance with the distance Cs. Further, when the distance Cd is set to be equal to or less than the thickness of the rubber composition to be discharged, for example, the pressurizing force of the compressed air supplied to the annular gap 14 is increased (for example, 0.05 to 0.05) while the rubber composition is being discharged. .1 MPa). As a result, the die swells at the moment the rubber composition is discharged from the extrusion port 228 (the wall thickness increases), and the force (force in the direction of diameter expansion) that resists the force that causes the diameter to shrink due to contraction due to cooling is applied to the rubber composition. An annular gap 14 (layer of compressed air flow) can be formed between the outer peripheral surface of the spun mold 10 and the ejected cylindrical rubber composition while acting on the object. As a guideline, the size of this annular gap 14 should be about 1 mm.

Further, when the front end of the cylindrical rubber composition discharged from the extrusion port 228 reaches the vicinity of the core wire 3 that is spun closest to the front gripping portion 12 side of the body portion 11 of the spun mold 10, the rubber The discharge of the composition is stopped and the compressed air supplied to the annular gap 14 is discharged. At that time, the annular rubber composition (thermoplasticized state) shrinks due to the contraction action due to cooling while the annular rubber composition and the spun mold 10 are kept substantially immovable in the front-rear direction. When the diameter is reduced, the annular gap 14 is closed, and the outer peripheral surface of the body portion 11 is closely attached so as to cling to it. As a result, the layer of the rubber composition does not generate shear stress on the core wire 3 spun in the mold 10, so that the spun core wire 3 is prevented from pitch disturbance (displacement of the core wire 3). can be

In addition, in the coating step, the layer of the thermoplastic rubber composition discharged from the extrusion port 228 (internal temperature immediately after discharge: approximately 90° C.) shrinks due to die swelling and temperature drop due to cooling. Furthermore, the diameter of the annular gap 14 is reduced by shifting to a negative pressure, and the radial distance Cd (Cd: For example, 2 mm) is excessively larger than the thickness of the rubber composition layer (T: for example, 1 mm) (for example, twice: see FIGS. 9 and 10), problems such as floating and vertical wrinkles Thus, an unvulcanized belt sleeve coated in layers on the outer peripheral surface of the spun mold 10 (body portion 11) is continuously obtained.

In this way, the distance Cd can be relatively large (twice as large in the present embodiment) as the thickness (T) of the rubber composition layered on the outer peripheral surface of the mold 10. , the peripheral length range of the mold 10 can be expanded as compared with the case where the annular gap 14 is not made to have a negative pressure. That is, it is possible to expand the peripheral length range of unvulcanized belt sleeves having the same thickness but different peripheral lengths. Therefore, productivity can be further improved as compared with the conventional extrusion method.

Further, the rotation of the screw 212 of the extruder 20 (ejection of the rubber composition from the extrusion port 228) is temporarily stopped every time one spun mold 10 is coated with the rubber composition. Then, in the vicinity of the concave groove portion 112d provided in the guide member 112 of the mold 10, the annularly discharged rubber composition is cut. As a result, the die 10 with the extruded unvulcanized belt sleeve is obtained.

(5) The resulting extruded unvulcanized belt sleeve-attached mold 10 is removed from the extruder 20 . A mold with an unvulcanized belt sleeve having an effective surface length of 400 mm can be obtained by simply exchanging the mold 10 with an unvulcanized belt sleeve that has been extruded and a new mold 10 that has been spun using the mold supply device 24. 10 can be obtained continuously.

(6) Place the mold 10 with the unvulcanized belt sleeve that has been removed on the pedestal of a vulcanizing device (see FIG. 3 of Patent Document 1, for example). Then, superheated steam is sent into the bladder through the valve hole at a predetermined pressure, the bladder is expanded by the steam pressure, the unvulcanized belt sleeve is radially compressed between the mold 10 and the bladder, and the tooth portion is Vulcanize while forming 2 (temperature: about 160° C., pressure: about 0.8 MPa, time: about 20 minutes) to obtain a vulcanized belt sleeve (effective surface length: 400 mm). (vulcanization process). As a result, teeth 2 (70 teeth, pitch between teeth 3 mm) are formed in the vulcanized belt sleeve.

(7) After the belt sleeve is cooled after vulcanization, the mold 10 is removed by a demolding device, and the vulcanized belt sleeve is taken out.

(8) A belt sleeve having an effective surface length of 400 mm is cut to a belt width of 10 mm by a width cutting device to obtain 40 toothed belts 1 (nominal: 100S3M210).

(Continuous operation of coating process)
The continuous operation performed in the coating step (4) of the manufacturing process of the toothed belt 1 will be described in detail.

The continuous operation performed in the coating process is automatically controlled by the control device 30 . At this time, an input device (not shown) of the control device 30 is used to input unvulcanized belt sleeve type information (type of base rubber composition, unvulcanized belt sleeve to be formed) that defines the specifications of the unvulcanized belt sleeve to be created. Peripheral length/face length of vulcanized belt sleeve, thickness (T) of rubber composition to be coated, outer diameter of mold 10, outer diameter of mold 10 after spinning, type of mold 10, size of mouthpiece 223 type, etc.) are input/selected. Based on the input/selected unvulcanized belt sleeve type information, the control unit 32 controls the continuous operation of the following steps.

(Before coating with rubber composition)
(4-1) The control unit 32 controls a series of supply operations of the mold 10 based on the mold supply position signal from the mold supply position detector 303. As shown in FIG. The chuck part 241 (vertically downward) of the device 24 is lowered from the front standby position 2 (vertically above the mold conveying device 26 described later). Then, after having the chuck part 241 (vertically downward) grip the front side gripping part 12 (vertically upward) of the spun mold 10 obtained in the spinning process, the chuck part 241 is raised to the front standby position 2. , so that the center axis of the spun mold 10 is arranged on the same axis as the center axis C of the extruder 20, the chuck part 241 holding the front side holding part 12 is swung clockwise by 90°, and the chuck is The part 241 is moved to the front standby position 1 (rotating the mold 10).

(4-2) Based on the internal pressure detection signal from the pressure detector 302, the control unit 32 increases the pressure inside the rubber composition flow path between the tip of the screw 212 and the extrusion port 228 from zero. (When the thermoplastic rubber composition (unvulcanized material) begins to fill near the inlet of the annular flow path 227), the mold supply position signal from the mold supply position detector 303 Based on this, the mold 10 is supplied in the mold feeding direction with the chuck portion 241 gripping the front gripping portion 12 of the spun mold 10, and the rear gripping portion 13 is inserted into the hole of the nipple 224 of the extruder 20. 229. As a result, the communication port 132 of the rear grip portion 13 is engaged with the convex member 230 incorporated in the hole 229 of the nipple 224 (FIG. 7: State I).

(4-3) The control unit 32 determines that the internal pressure detection signal (pressure value) from the pressure detector 302 indicates that the rubber composition (unvulcanized material) has flowed to the vicinity of the extrusion port 228. (for example, 25 MPa), the pressurizing device 231 (hot air generator) of the pressure source 23 is activated, and the outer peripheral surface of the spun die 10 and the extruded product are discharged at the reference extrudate cylindrical internal pressure. Compressed air supply is started between the cylindrical rubber composition (Fig. 4: Compressed air supply path, Fig. 7: State II-1). The ambient temperature of the compressed air is adjusted to, for example, around 50° C. by an electric heater and a temperature regulator provided in the pressurizing device 231 (hot air generator). In addition, this reference extrudate cylindrical internal pressure is the pressure stored in the setting information storage unit 31 in advance, and the screw rotation speed (for example, 5 rpm) set for each unvulcanized belt sleeve type information. is the pressure corresponding to the discharge rate of the rubber composition from the extrusion port 228, based on The control unit 32 controls the supply/stop operation of the compressed air by the pressurizing device 231 based on the reference extrudate tubular internal pressure signal read out from the setting information storage unit 31 .

(Coating of rubber composition)
(4-4) Compressed air is continuously supplied between the outer peripheral surface of the spun mold 10 and the discharged cylindrical rubber composition, so that the rubber composition is cylindrically discharged from the extrusion port 228. The rubber composition (cylindrical rubber composition) expands slightly (slightly expands the outer diameter, and extends to the outside of the outer peripheral surface of the spun mold 10 (the state in which the core wire 3 is spun). (so as to cover it in a non-contact manner) and is ejected forward (in the ejection direction). That is, an annular gap 14 is formed between the outer peripheral surface of the spun mold 10 and the ejected cylindrical rubber composition (FIG. 7: State II-2).

(4-5) Based on the extrudate tip position signal from the extrudate tip position detector 304, the control unit 32 detects that the front end of the discharged rubber composition is the body portion 11 of the spun mold 10, When it is determined that it has reached the vicinity of the spun core wire 3 closest to the front gripping part 12 side, the rotation of the screw 212 of the extruder 20 is temporarily stopped, and the supply of compressed air by the pressurizing device 231 is stopped (Fig. 7) : State III).

Substantially at the same time as stopping the supply of compressed air by the pressurizing device 231, the control unit 32 activates the suction device (vacuum pump) of the negative pressure device 232, and the switching valve causes the piping route to be drawn from the pressurizing device 231 side. Switch to the pressure device 232 side. As a result, the compressed air in the annular gap 14 is quickly exhausted, the annular gap 14 becomes a negative pressure (air pressure lower than the atmospheric pressure), and the thermoplastic resin discharged from the extrusion port 228 is contracted due to cooling. The layer (cylindrical shape) of the rubber composition thus formed is reduced in diameter, and while the annular gap 14 is closed, it clings (closely adheres) to the outer peripheral surface of the body portion 11 of the mold 10, and the body portion of the mold 10. The outer peripheral surface of 11 is coated with a layered rubber composition without problems such as floating or vertical wrinkles (completion of rubber coating) (Fig. 8: state IV). As a result, the inner peripheral side of the rubber composition discharged in layers into the body portion 11 of the mold 10 becomes negative pressure, and the outer peripheral side of the rubber composition is kept at atmospheric pressure (the inner peripheral side and the outer peripheral side of the rubber composition By creating a pressure difference between the side and the side), the adhesion of the layered rubber composition to the tooth cloth 6 coated on the outer peripheral surface of the body portion 11 and the spun cord 3 is improved compared to the case where the negative pressure is not applied. are improving.

Here, the extrusion port 228 of the extruder 20 is attached to the core wire 3 spun to the body portion 11 of the mold 10 (the core wire 3 spun to the rearmost gripping portion 13 side) of the mold 10. They are arranged at positions spaced apart by a predetermined distance Cs in the direction of the central axis. Then, after the rubber composition is discharged from the extrusion port 228, the front end of the discharged rubber composition is the spun core wire 3 that is closest to the front grip part 12 side of the body part 11 of the spun mold 10. Compressed air is supplied to the annular gap 14 until it reaches the vicinity. As a result, during this time, the rubber composition being discharged from the extrusion port 228 can be prevented from coming into contact with the outer peripheral surface (core wire 3) of the spun mold 10. In the case of the settings of Examples 1 to 3 described later, after the rubber composition is discharged from the extrusion port 228, the front end of the discharged rubber composition is the most of the body portion 11 of the spun mold 10. It takes about 7 seconds to reach the vicinity of the core wire 3 spun on the front grip part 12 side. Since the temperature has decreased by only 3° C., it is still in a state in which the diameter can be sufficiently reduced by the contraction action due to cooling when the compressed air supplied to the annular gap 14 is exhausted. As a result, the ring-shaped rubber composition (thermoplasticized state) contracts due to shrinkage caused by cooling, closes the ring-shaped gap 14 , and adheres tightly to the outer peripheral surface of the body portion 11 so as to cling to it. As a result, the layer of the rubber composition does not generate shear stress on the core wires 3 spun in the mold 10, so that pitch disturbance (displacement of the core wires 3) does not occur in the spun core wires 3. can be

In addition, since the guide member 112 is provided, even if the rubber composition discharged from the extrusion port 228 contacts the guide member 112, the tapered outer peripheral surface 112a of the guide member 112 and the compressed air prevent the rubber composition from spinning. Since the rubber composition is guided to the outer peripheral side of the die 10, the rubber composition can be discharged from the extrusion port 228 to the outer peripheral side of the spun die 10 reliably and smoothly.

In addition, the control unit 32 controls the thickness of the coated rubber composition obtained by the sleeve outer diameter measuring device 306 or the like when the outer peripheral surface of the body portion 11 of the mold 10 is coated with the layered rubber composition. Based on the actual value, by executing feedback control to converge the thickness of the rubber composition coated on the spun mold 10 supplied next time onward to the target value, the screw from the screw rotation speed detector 301 Based on the rotation speed signal, the rotation speed of the drive motor 213 is controlled (finely adjusted), and the rotation speed of the screw 212 (proportional to the amount of rubber composition discharged from the extrusion port 228) is sequentially finely adjusted.

In addition, in order to deal with uneven thickness (actual value) in the circumferential direction of the layered rubber composition coated on the outer peripheral surface of the body portion 11 of the mold 10, alignment work (during the operation stop of the extruder 20 the aligning bolt is pushed and pulled to move the die 225 in the radial direction) is appropriately performed as necessary.

(4-6) The control unit 32 uses the cutting device 25 to press the rubber composition layer coated on the outer peripheral surface of the body portion 11 to the bottom of the groove portion 112d of the guide member 112, and in that state, 1 turn and cut. This completely separates the mold 10 with the extruded unvulcanized belt sleeve and the layer of rubber composition discharged from the extrusion port 228 .

(4-7) Based on the cutting detection signal from the cutting detector 305 indicating the completion of cutting by the cutting device 25, the control unit 32 controls the chuck holding the extruded mold 10 with the unvulcanized belt sleeve. The part 241 is moved to the front standby position 1 (FIG. 8: state V). The mold 10 with this unvulcanized belt sleeve is removed and transferred to the vulcanization process.

Specifically, based on the mold supply position signal from the mold supply position detector 303, the control unit 32 controls a series of mold supply operations shown in the following 1) to 3).

1) The control unit 32 causes the mold supply drive unit 243 to move the chuck unit 241 that grips the front gripping unit 12 of the unvulcanized belt sleeve attached mold 10 to the front standby position 1, and then moves the mold. The die rotation drive section 244 swings the chuck section 241 counterclockwise by 90° so that the center axis of the die 10 is directed vertically downward, thereby rotating the die 10 .

2) Next, the control unit 32 causes the mold supply drive unit 243 to move the chuck unit 241 vertically downward, and moves the rear gripping unit 13 of the unvulcanized belt sleeve attached mold 10 to the mold conveying device 26. (Refer to FIG. 6). The mold conveying device 26 is controlled by a control section (the mold conveying device 26) that is separate from the operation performed in the coating process, and rotates the spinning process, the coating process, and the vulcanizing process to perform metal molding. It is a device for conveying the mold 10 .

3) Next, the control unit 32 releases the gripping of the front gripping part 12 of the mold 10 with an unvulcanized belt sleeve, and moves the chuck part 241 to the front standby position 2 (or a position where the front gripping part 12 does not interfere). is lifted, the mold 10 with the unvulcanized belt sleeve is removed, and the process proceeds to the vulcanization step.

Next, the control unit of the separate system (mold conveying device 26) causes the mold conveying device 26 to move the unvulcanized belt sleeve-equipped mold 10 to the vulcanization process, and a new spun mold 10 (the rear gripping portion 13 of the mold 10 faces vertically upward) is transported directly below the front standby position 2 .

(4-8)
After that, under the control of the control unit 32, the operation returns to (4-1). By repeating the above operations (4-1) to (4-7) by the control unit 32, the outer peripheral surface of the spun mold 10 is continuously coated with a cylindrical rubber composition layer. Obtain a vulcanized belt sleeve.

According to the above, it is possible to automatically control the series of operations of the mold supply device 24, the pressure source 23 and the like for each specification of the unvulcanized belt sleeve. As a result, labor saving is further advanced compared to the conventional method, and productivity is further improved.

According to the above manufacturing method, in the covering step, compressed air is supplied between the outer peripheral surface of the spun mold 10 and the rubber composition discharged in a cylindrical shape, thereby expanding the rubber composition in a cylindrical shape. A radial force can be applied to form an annular gap 14 between the outer peripheral surface of the spun mold 10 and the cylindrically discharged rubber composition. As a result, the rubber composition can be prevented from coming into contact with the core wire 3 spun on the outer peripheral surface of the mold 10 while the thermoplastic rubber composition is discharged in a cylindrical shape.

Furthermore, when the cylindrically discharged rubber composition reaches a predetermined position on the outer peripheral surface of the spun mold 10, the discharge of the rubber composition is stopped and the compressed air is discharged to close the annular gap 14. As a result, the force acting on the tubular rubber composition in the radially expanding direction is eliminated. As a result, the diameter of the thermoplasticized tubular rubber composition is reduced due to the contraction action caused by cooling, and the rubber composition is brought into close contact with the outer peripheral surface of the spun mold 10 . As a result, the rubber composition discharged in a cylindrical shape forms a layer on the outer peripheral surface of the spun mold 10 without generating shear stress on the core wire 3 spun on the outer peripheral surface of the mold 10. will be covered by In other words, it is possible to prevent the cords 3 from being disturbed in pitch (displacement of the cords 3) in the covering process for forming the unvulcanized belt sleeve.

Further, in the above coating step, the die 10 with the unvulcanized belt sleeve that has been extruded and the new die 10 that has been spun are exchanged by the die supply device 24, and the outer peripheral surface of the die 10 is cylindrical. It is possible to continuously mold an unvulcanized belt sleeve coated with a layer of rubber composition having a shape. Therefore, compared to the conventional method (requiring a series of complicated processes of sheeting by rolling equipment such as calendar rolls, cutting, winding on a mold, and jointing), the productivity related to the production of the rubber toothed belt 1 is improved. can be improved.

Further, by simply replacing the mold 10 with one having a different peripheral length, it is possible to mold, for example, unvulcanized belt sleeves having the same thickness but slightly different peripheral lengths. Therefore, when the distance between the extrusion port 228 and the outer peripheral surface of the spun mold 10 is approximately the same as the thickness of the rubber composition layer, as in the conventional extrusion method, the thickness of the rubber composition layer is Even if the thickness is the same, if the circumference is slightly different, the die 10, the die 225 and the nipple 224 must be exchanged, so that the productivity is improved more than before.

Also, by adjusting the pressurizing force of the compressed air between the outer peripheral surface of the spun mold 10 and the cylindrically discharged rubber composition, only the mold 10 can be replaced with one having a different circumferential length. For example, it is possible to form unvulcanized belt sleeves having the same thickness but slightly different circumferential lengths. In this regard, when the distance (radial direction) between the extrusion port and the outer peripheral surface of the die is approximately the same as the thickness of the layer of the rubber composition (conventional extrusion method, FIG. 1 of Patent Document 1, and comparison described later) 14 of Example 1), even if the thickness of the rubber composition layer is the same, if the circumference is slightly different, the mold, die, and nipple must be replaced. improves.

In addition, after the cutting device 25 cuts the layer of the rubber composition coated on the outer peripheral surface of the body portion 11, the rubber composition remaining in the vicinity of the extrusion port 228 (for example, about 10 mm in length, the tip portion where cooling proceeds) (Reused as return rubber) is left in the vicinity of the extrusion port 228 in a shape with a reduced diameter at the tip (a bulging state), but as described above, the body of the mold 10 11, the outer peripheral surface 112a of the guide member 112 provided at the end on the rear grip portion 13 side has a tapered shape as shown in FIG. When the mold 10 is supplied, the tip of the rubber composition remaining in the vicinity of the extrusion port 228 can be brought into contact with the tapered outer peripheral surface 112a to cover the outside of the guide member 112 (Fig. 8 state V→state I in FIG. 7). Therefore, immediately after the rubber composition is discharged from the extrusion port 228, the rubber composition smoothly receives the flow (wind pressure) of the supplied compressed air, and when the length of the remaining rubber composition is relatively short. (For example, about 4 mm), the cross-sectional shape of the tip of the remaining rubber composition can be increased along the tapered outer peripheral surface 112a while maintaining a substantially perfect circle. Therefore, bending of the tip of the rubber composition and occurrence of displacement of the core wire 3 due to contact of the tip of the rubber composition with the outer peripheral surface (core wire 3) of the spun mold 10, etc. It is possible to suppress the generation of waste and defects related to the process.

(Other embodiments)
In the coating step of the above embodiment, the front end of the tubular rubber composition discharged from the extrusion port 228 is positioned on the body portion 11 of the spun mold 10, and the spun core wire 3 is closest to the front grip portion 12 side. When the pressure reaches the vicinity, the negative pressure is applied to the annular gap 14 by the negative pressure device 232. However, the negative pressure device 232 is not an essential component, and the annular gap 14 does not have to be negative pressure. That is, the pressurizing device 231 may be turned off and the compressed air in the annular gap 14 may be naturally exhausted (atmospheric pressure).

Further, in the above-described embodiment, the structure and arrangement are such that the discharge direction of the rubber composition from the extrusion port 228 is horizontal. ) or against gravity (vertically upward). In this case, a crosshead is connected to the extruder 20 instead of the straight head 22 as in this embodiment. In this case, the effect of gravity on the outer peripheral surface of the spun mold 10 of the discharged rubber composition can be made uniform, and biased deformation of the discharged rubber composition due to gravity can be prevented. As a result, the uniformity of the thickness of the rubber composition layer of the unvulcanized belt sleeve obtained and the connection between the rubber composition and the cord are improved compared to the case where the rubber composition is discharged in a substantially horizontal direction. Adhesion can be improved.

Also, the series of operations performed in the coating process may be performed manually without being controlled by the control unit 32 (computer control).

Also, the extruder 20 may not be equipped with the cutting device 25 . In this case, in the coating step, for example, after rubber coating is completed (screw 212 is in a temporary stop state), the control unit 32 controls the mold supply operation to slightly move the mold 10 forward (preferably, The mold 10 is moved while the annular gap 14 is held at a negative pressure). As a result, a layer of the rubber composition is formed between the extrusion port 228 and the core wire 3 spun on the outer peripheral surface of the spun mold 10 (the core wire 3 spun on the rearmost gripping portion 13 side). Stretched and cut. According to this method, a space for the cutting device 25 does not have to be secured in front of the die 225, so the distance Cs can be shortened.

In addition, in the coating process of the above embodiment, the outer diameter of the body portion 11 of the die 10 after spinning (including the thickness of the tooth cloth 6 and the core wire 3) is the same as the diameter of the inner peripheral surface of the die 225 (annular pressing). However, the outer diameter of the body portion 11 of the die 10 after spinning may be set to be equal to or larger than the diameter of the inner peripheral surface of the die 225 . In this case, the outer diameter of the body portion 11 of the die 10 after spinning (including the thickness of the tooth cloth 6 and the cord 3) is larger than the diameter of the inner peripheral surface of the die 225 (the inner diameter of the annular extrusion port 228). This can be handled by setting the distance Cs longer and setting the pressurizing force (P1) of the compressed air supplied to the annular gap 14 higher than when it is set to be small.

(comparison)
In the following, the toothed belt 1 produced by the production methods of Examples 1 to 3 according to the present invention and the toothed belt 1 produced by the conventional extrusion method (Comparative Example 1) were comparatively evaluated. Further, in Examples 1 to 3, "the radial distance Cd of the mold 10 between the extrusion port 228 and the outer peripheral surface of the spun mold 10", "the extrusion port 228 and the body part of the mold 10 11 (the core wire 3 spun to the rearmost gripping portion 13 side) Cs”, “the amount of compressed air (ambient temperature: around 50°C) supplied to the annular gap 14 Unvulcanized belt sleeves and vulcanized belts obtained by a manufacturing method in which various settings such as pressure P1 and pressure P2 after exhausting compressed air from the annular gap 14 (presence or absence of negative pressure) are changed. The sleeve and toothed belt were comparatively evaluated.

In order to obtain an unvulcanized belt sleeve (toothed belt) by the manufacturing method carried out in Examples 1 to 3 and Comparative Example 1, the target unvulcanized belt sleeve specifications (tooth cloth, cord, rubber Specifications such as composition material, structure, thickness, etc.), the surface length of the body of the mold, the cross-sectional shape around the extrusion port, and the discharge speed of the extrudate were set substantially the same.

(Common settings in Examples 1 to 3 and Comparative Example 1) · Size of clearance of extrusion port (Co): 0.5 mm · Thickness of layer of rubber composition (T): 1 mm · Screw rotation speed (N ): 5r. p. m. →As a result, the discharge speed (V) of the rubber composition from the extrusion port: about 4 m / min ・The surface length of the body part of the mold: 450 mm

(Example 1)
In Example 1, as shown in FIGS. 9 and 10, the distance Cd in the radial direction of the mold 10 between the extrusion port 228 and the outer peripheral surface of the spun mold 10 is the layer of the rubber composition. This is an example in which the thickness is set to be excessively larger than the thickness (T) of .

Specifically, in the first embodiment, the settings are as follows.・Distance Cd: 2 mm ・Distance Cs: 13 mm ・Pressure P1: 0.02 MPa ・Pressure P2: Negative pressure

(Example 2)
Example 2 is the same as Example 1 except that the pressure P2 is the atmospheric pressure.・Distance Cd: 2 mm ・Distance Cs: 13 mm ・Pressure P1: 0.02 MPa ・Pressure P2: Atmospheric pressure

(Example 3)
In Example 3, as shown in FIG. 11 and FIG. This is an example in which the thickness (T) is set to be the same as the thickness (T) of . The pressurizing force P1 of the compressed air supplied to the annular gap 14 is set relatively high.・Distance Cd: 1 mm ・Distance Cs: 13 mm ・Applied pressure P1: 0.05 MPa ・Pressure P2: atmospheric pressure

(Comparative example 1)
Comparative Example 1, as shown in FIGS. 13 and 14, is a conventional extrusion method in which a spun mold is continuously supplied to the inside of the inner cylindrical portion of the crosshead, and the rubber composition is applied to the outer peripheral surface of the mold. This is an example of trying to determine whether it is possible to cover-mold (unvulcanized product) without problems. Similarly, it was set to have the same dimension as the thickness of the rubber composition layer (T: 1 mm).

(Evaluation item)
Evaluation items, evaluation methods, and evaluation criteria for evaluating the toothed belts according to Examples 1 to 3 and Comparative Example 2 are described below.

(Productivity)
If it can be judged that unvulcanized belt sleeves can be continuously obtained by the relevant manufacturing method (extrusion molding) and productivity has improved compared to the conventional method, it will be marked as "○", and the circumference of the mold If it can be judged that productivity has improved more than the conventional method, such as the possibility of expanding the range, it will be marked with "◎", and unvulcanized belt sleeves can be obtained continuously by the corresponding manufacturing method (extrusion molding). When it was judged that the productivity could not be improved compared to the conventional method (including the case of frequent occurrence of quality defects such as misalignment of the core wires), it was evaluated as "x".

(uniformity)
For a plurality of unvulcanized belt sleeves obtained by each manufacturing method, as a result of confirming the dimensions etc. before the vulcanization process, the thickness of the rubber composition layer coated on the unvulcanized belt sleeve (about 1 mm) However, if it was uniform, it was evaluated as “◯”, and if it was non-uniform, it was evaluated as “×”.

(Adhesion)
As a result of confirming a plurality of unvulcanized belt sleeves obtained by each manufacturing method before the vulcanization process, the adhesion between the rubber composition layer coated on the unvulcanized belt sleeve and the core wire was good. If (no float), it was evaluated as "○"; if it was better (strong bite of core wire), it was evaluated as "⊚";

(core misalignment)
Regarding the unvulcanized belt sleeve and the vulcanized belt sleeve obtained by each manufacturing method, as a result of observing the cross section along the sleeve length (surface length) direction, the pitch disturbance in the core wire (longitudinal direction of the mold) When there was no misalignment, it was evaluated as "○", and when there was, it was evaluated as "X".

(quality)
The quality (static and dynamic) of the toothed belt (designation: 100S3M210) obtained by each manufacturing method is comparable to the quality of the toothed belt obtained by the conventional method, and defects caused by the manufacturing method was evaluated as "◯" when there was no such material, and as "x" when it was present.

(Evaluation results)
The unvulcanized belt sleeve, the vulcanized belt sleeve, and the toothed belt obtained by the settings of Examples 1 to 3 and Comparative Example 1 were checked for conditions, dimensions, and the like. Table 1 shows the evaluation results.

※各例において、設定値Ｃｏ（０．５ｍｍ）、Ｔ（１ｍｍ）、Ｎ（５ｒ．ｐ．ｍ．）は、共通。

*In each example, the set values Co (0.5 mm), T (1 mm), and N (5 r.p.m.) are common.

(Productivity: Examples 1 to 3)
In the manufacturing method (extrusion molding) of Examples 1 to 3, unvulcanized belt sleeves could be obtained continuously.

(Uniformity, adhesion: Examples 1 to 3)
As a result of confirming the dimensions and the like of the obtained unvulcanized belt sleeves before the vulcanization process, the thickness (about 1 mm) of the rubber composition layer coated on the unvulcanized belt sleeves was uniform and There was no problem with the adhesion to the core wire (Regarding the adhesion, in Example 1, by setting P2 to a negative pressure, compared to Examples 2 and 3, the core wire bit into the core wire more. It was good.

(Wire misalignment: Examples 1 to 3)
In addition, as a result of observing the cross section along the sleeve length (surface length) direction of the unvulcanized belt sleeve and the vulcanized belt sleeve, there was no pitch disturbance (shift in the longitudinal direction of the mold) in the core wire. I didn't.

(quality)
The quality (static and dynamic) of the obtained toothed belt (designation: 100S3M210) was comparable to the quality of the toothed belt obtained by the conventional method, and there was no problem caused by the manufacturing method. .

(Comparative example 1)
On the other hand, in Comparative Example 1, an unvulcanized belt sleeve could be continuously obtained by the above manufacturing method. As a result, it was confirmed that pitch disturbance (displacement in the longitudinal direction of the mold) occurred in the core wire. Therefore, it was found that in the conventional extrusion method of Comparative Example 1, it is difficult to achieve both quality and productivity.

As a result of the above comparison, in Examples 1 to 3, compared to the conventional extrusion method like Comparative Example 1, it was found that productivity can be further improved while maintaining quality.

Reference Signs List 1 Toothed belt 2 Teeth 3 Cord 4 Back 5 Belt main body 6 Tooth cloth 100 Manufacturing device 10 Mold 11 Body 12 Front grip 13 Rear grip 14 Annular gap 20 Extruder 21 Main body 212 Screw 22 Straight head 221 Head body 222 Supporting member 223 Mouthpiece 224 Nipple 225 Die 227 Annular flow path 228 Extrusion port C Central axis

Claims (8)

A belt body made of a rubber composition having a plurality of teeth provided at predetermined intervals in the circumferential direction of the belt and a back portion in which cords are embedded, wherein the surfaces of the plurality of teeth A method for manufacturing a toothed belt coated with a tooth cloth,
a spinning step of mounting the cylindrical tooth cloth on the outer periphery of a mold having a tooth profile formed on the cylindrical outer peripheral surface, and spinning the cord on the tooth cloth;
The thermoplastic rubber composition is discharged in a cylindrical shape onto the outer peripheral surface of the spun mold in which the cord is spun on the tooth cloth, and the outer peripheral surface is covered to be unvulcanized. a coating step to form a belt sleeve;
a vulcanization step of vulcanizing the unvulcanized belt sleeve while pressurizing it from the outer peripheral side to form the tooth portion;
In the coating step,
By continuously supplying compressed air between the outer peripheral surface of the spun mold and the rubber composition discharged in a cylindrical shape, the outer peripheral surface of the spun mold and the cylindrical rubber composition forming an annular gap between the rubber composition discharged to
When the rubber composition discharged in a cylindrical shape reaches a position overlapping the entire spun core wire on the outer peripheral surface of the mold, the discharge of the rubber composition is stopped and the compressed air is discharged. A method for manufacturing a toothed belt, characterized in that the annular gap is closed by: In the coating step,
Arrange the spun mold in an extruder having an annular extrusion port so that the center of the annular extrusion port is arranged on an extension line of the central axis of the mold,
Furthermore, the core wire spun in the mold and the extrusion port are arranged at a predetermined distance in the central axis direction of the mold,
The thermoplastic rubber composition is discharged in a cylindrical shape from the extrusion port, and the outer peripheral surface of the spun mold is covered to form an unvulcanized belt sleeve. Item 1. A method for manufacturing a toothed belt according to item 1. In the coating step,
3. The method of manufacturing a toothed belt according to claim 1, wherein the annular gap is set to a negative pressure lower than atmospheric pressure when the compressed air is exhausted. The extruder is
a screw for discharging the rubber composition from the extrusion port;
A screw rotation speed detector that detects the rotation speed of the screw and transmits it as a screw rotation speed signal;
a pressure detector that detects the pressure inside the rubber composition flow path between the tip of the screw and the extrusion port and transmits it as an internal pressure detection signal;
a mold supply device that supplies the mold so that the center of the extrusion port is arranged on an extension of the central axis of the mold;
a mold supply position detector that detects the position of the mold and transmits it as a mold supply position signal;
a pressure source for supplying and discharging the compressed air;
an extrudate tip position detector that detects that the rubber composition has reached a predetermined position on the outer peripheral surface of the spun mold and transmits it as an extrudate tip position signal;
a cutting device;
a cutting detector that detects completion of cutting of the unvulcanized belt sleeve by the cutting device and transmits a cutting detection signal;
Unvulcanized belt sleeve type information that defines the specifications of the unvulcanized belt sleeve, and from the extrusion port of the rubber composition based on the rotation speed of the screw set for each of the unvulcanized belt sleeve type information Setting information for storing discharge speed information that defines the discharge speed of and reference extrudate tubular internal pressure information that defines the pressure applied to the rubber composition by the pressure source corresponding to the discharge speed information a storage unit;
The screw rotation speed signal from the screw rotation speed detector, the internal pressure detection signal from the pressure detector, the mold supply position signal from the mold supply position detector, and the extrudate tip position detector Based on at least one of the extrudate tip position signal, the reference extrudate cylindrical internal pressure information read from the setting information storage unit, and the cut detection signal from the cut detector, the mold a control unit that controls the operation of the supply device and the pressure source;
3. The method of manufacturing a toothed belt according to claim 2, wherein the operation of said mold supply device and said pressure source is controlled by said control unit for each of said unvulcanized belt sleeve type information. A belt body made of a rubber composition having a plurality of teeth provided at predetermined intervals in the circumferential direction of the belt and a back portion in which cords are embedded, wherein the surfaces of the plurality of teeth A device for manufacturing a toothed belt coated with a tooth cloth,
an extruder having an annular extrusion port;
a mold that is detachable from the extruder so that a tooth profile is formed on the cylindrical outer peripheral surface and the center of the annular extrusion port is arranged on the extension line of the central axis;
An annular ring formed between the cylindrical rubber composition extruded from the extrusion port and the mold in which the core wire is spun on the cylindrical tooth cloth attached to the outer peripheral surface of the mold An apparatus for manufacturing a toothed belt, comprising: a pressure source capable of supplying compressed air to the gap and discharging the compressed air from the annular gap. The mold is attached to the extruder so that the cord spun in the mold and the extrusion port are arranged at a predetermined distance in the central axis direction of the mold. The apparatus for manufacturing a toothed belt according to claim 5, characterized by: 7. The toothed toothed structure according to claim 5, wherein the pressure source can be set so that the annular gap becomes a negative pressure lower than the atmospheric pressure when the compressed air is exhausted. Belt manufacturing equipment. The extruder is
a screw for discharging the rubber composition from the extrusion port;
A screw rotation speed detector that detects the rotation speed of the screw and transmits it as a screw rotation speed signal;
a pressure detector that detects the pressure inside the rubber composition flow path between the tip of the screw and the extrusion port and transmits it as an internal pressure detection signal;
a mold supply device that supplies the mold so that the center of the extrusion port is arranged on an extension of the central axis of the mold;
a mold supply position detector that detects the position of the mold and transmits it as a mold supply position signal;
an extrudate tip position detector that detects that the rubber composition has reached a predetermined position on the outer peripheral surface of the spun mold and transmits it as an extrudate tip position signal;
a cutting device;
a cutting detector that detects completion of cutting of the unvulcanized belt sleeve by the cutting device and transmits a cutting detection signal;
Unvulcanized belt sleeve type information that defines the specifications of the unvulcanized belt sleeve, and from the extrusion port of the rubber composition based on the rotation speed of the screw set for each of the unvulcanized belt sleeve type information Setting information for storing discharge speed information that defines the discharge speed of and reference extrudate tubular internal pressure information that defines the pressure applied to the rubber composition by the pressure source corresponding to the discharge speed information a storage unit;
The screw rotation speed signal from the screw rotation speed detector, the internal pressure detection signal from the pressure detector, the mold supply position signal from the mold supply position detector, and the extrudate tip position detector Based on at least one of the extrudate tip position signal, the reference extrudate cylindrical internal pressure information read from the setting information storage unit, and the cut detection signal from the cut detector, the mold a control unit that controls the operation of the supply device and the pressure source;
The toothed belt according to any one of claims 5 to 7, wherein the operation of the mold supply device and the pressure source is controlled by the control unit for each of the unvulcanized belt sleeve type information. manufacturing equipment.

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