JP4329925B2 - Transmission belt manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a power transmission belt, and more particularly relates to a method of manufacturing a power transmission belt with reduced noise during precisely molded by raising the short fibers of the nonwoven fabric attached to the transmission surface of the rib portion of belt travel.
[0002]
[Prior art]
Conventionally, as a method for orienting short fibers in a certain direction in unvulcanized rubber, uncured rubber containing short fibers is put into a pair of calender rolls whose rotation speed is changed in the rolling sheet manufacturing process and rolled. The short fibers in the rubber sheet were oriented in the rolling direction of the sheet and cut according to the belt width to be molded. Thereafter, a belt molded body obtained by laminating several rolled sheets cut in the laminating process and laminating them to a predetermined thickness, and subsequently winding a laminate in which short fibers are oriented in the width direction in a winding process around a molding drum. The belt was manufactured by vulcanizing and grinding a plurality of ribs on the surface of the belt sleeve by a glider wheel, and projecting short fibers on the surface of the rib to reduce noise during running. However, unless the thickness of the rolled sheet is reduced, the short fibers cannot be sufficiently oriented in the sheet rolling direction, and the sheets are unavoidably stacked. Was.
[0003]
As a method for improving this, it has also been proposed to use a short fiber-containing rubber composition formed into a sheet by an expansion die for a transmission belt. For example, in Patent Document 1, a cylindrical rib rubber tube is extruded by an extruder equipped with an expansion die having a V rib portion molding groove at an outlet portion, and a V ribbed belt molded body is formed on a mold using a sheet obtained by cutting the rib rubber tube. Is molded, vulcanized, and the rib surface of the V-rib portion of the belt molded body is ground to expose the short fibers on the surface of the rib portion to produce a V-ribbed belt with reduced noise during running. ing.
[0004]
On the other hand, in addition to exposing the short fibers to the surface of the rib portion by such a grinding method, Patent Document 2 provides napping on at least one transmission portion contact surface of the power transmission side and the transmission surface by electrostatic flocking, and running A power transmission member with reduced noise is described.
[0005]
Further, Patent Document 3 discloses a transmission belt provided with a driving surface having a friction coefficient increased by mounting a flocked fabric on the belt surface.
[0006]
[Patent Document 1]
JP-A-8-74936 [Patent Document 2]
Japanese Patent Laid-Open No. 9-14361 [Patent Document 3]
JP-A-2001-82549
[Problems to be solved by the invention]
However, in the method of manufacturing a transmission belt having a rib portion, if the hair is raised directly on the surface of the rib portion by electrostatic flocking, even if flocking can be made near the entrance of the V-shaped rib groove, the flocking is deep in the rib groove. Development of a new manufacturing method has been desired. On the other hand, when a flocked fabric is used, an adhesive is applied to a fabric (substrate) such as a non-woven fabric, and a short fiber flock is mechanically and electrostatically attached to the fabric to produce a belt. In order to lap-join or butt-join the end portions of the flocked fabric, there is a possibility that peeling occurs from the joint portion of the fabric after forming the belt.
[0008]
The present invention pays attention to such a problem and, as a result of earnest research, provides a method of manufacturing a transmission belt in which short fibers of a nonwoven fabric adhering to the transmission surface of a correctly formed rib portion are raised to reduce noise during belt running. For the purpose.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present application is a transmission belt having a rubber layer in which a core wire is embedded along the longitudinal direction of the belt and a rib portion adjacent to the rubber layer and extending in the longitudinal direction of the belt. In the manufacturing method of
Between the inner mold with a flexible jacket on the outer peripheral surface and the outer mold engraved with a rib mold on the inner peripheral surface, a laminate of a rubber sheet and a nonwoven fabric is interposed,
An unvulcanized preform is prepared by inflating the flexible jacket so that the nonwoven fabric of the laminate is in close contact with the stamped rib mold of the outer mold,
Wrap at least the core wire around the inner flexible jacket surface separated from the outer mold,
Again, the inner mold is installed in the outer mold, the flexible jacket is expanded, and the core wire is vulcanized integrally with the preform molded on the outer mold,
Demold to produce a vulcanized belt sleeve with ribs,
In the method of manufacturing a power transmission belt, the surface of the rib portion of the vulcanized belt sleeve is ground to raise short fibers of a nonwoven fabric.
[0010]
In this manufacturing method, it is possible to accurately mold the rib portion of the vulcanized belt sleeve using a laminate of a rubber sheet and a nonwoven fabric, and a portion of the short fibers of the nonwoven fabric is raised by polishing the surface of the rib portion. Accordingly, the present invention provides a method for manufacturing a transmission belt that reduces noise during belt running.
[0011]
The invention according to claim 2 of the present application resides in a method for manufacturing a transmission belt, in a laminate of a rubber sheet and a nonwoven fabric, containing short fibers in which the rubber sheet is oriented.
[0012]
Invention of Claim 3 of this application exists in the manufacturing method of the transmission belt in which this rubber sheet does not contain a short fiber in the laminated body of a rubber sheet and a nonwoven fabric.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
In the present invention, a rubber sheet in which short fibers are oriented in the width direction is produced. As a production method thereof, there are an extrusion method and a rolling method using a calendar. Of course, a rubber sheet which does not contain short fibers can also be used. When producing a rubber sheet in which fibers are oriented in the width direction by an extrusion method, 10 to 40 parts by mass of short fibers are added to 100 parts by mass of the polymer in advance using an open roll, and then the kneaded master batch is prepared. Once discharged, it is cooled to 20-50 ° C to prevent rubber scorching.
[0017]
When 1 to 10 parts by mass of a softening agent is added, the familiarity between the short fibers and the rubber is improved, and the dispersion into the rubber is improved. In addition, the short fibers themselves are prevented from being entangled and becoming cottony. In other words, the softener penetrates into the short fibers and acts as a lubricant to loosen the entanglement between the elementary fibers, prevents the short fibers from becoming cottony, and the familiarity between the short fibers and the rubber. Improves short fiber dispersion [0018]
Subsequently, a single rubber sheet in which short fibers are oriented in the width direction can be finished using an extrusion apparatus in which an expansion die is attached to an extruder. Although not shown here, after the master batch is kneaded with the extrusion screw of the cylinder in the extruder, the rubber mixed with the short fiber is located between the inner dies arranged on the same central axis at the position facing the cylinder. Cylindrical molded body in which short fibers are oriented in the circumferential direction while flowing through the rubber passage of the expansion die smoothly without being disturbed by the flow in the rubber passage and without changing the flow direction. Extruded.
[0019]
After that, the cylindrical molded body without weld line continuously extruded is one having a thickness of 1 to 10 mm in which short fibers are uniformly oriented in the circumferential direction from the inner layer to the outer layer. Then, one short fiber oriented rubber sheet is formed, and then the rubber sheet is cut at a predetermined interval.
[0020]
As rubber used here, natural rubber, butyl rubber, styrene-butadiene rubber, chloroprene rubber, ethylene-propylene rubber, alkylated chlorosulfonated polyethylene, hydrogenated nitrile rubber, hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt Or a rubber material such as ethylene-α-olefin elastomer made of ethylene-propylene rubber (EPR) or ethylene-propylene-diene monomer (EPDM), or a mixture thereof. Examples of diene monomers include dicyclopentadiene, methylene norbornene, ethylidene norbornene, 1,4-hexadiene, cyclooctadiene, and the like.
[0021]
The rubber is made of fibers such as aramid fiber, polyamide fiber, polyester fiber, and cotton, and the length of the fiber varies depending on the type, but a short fiber of about 1 to 10 mm is used, for example, 3 to 5 mm for an aramid fiber. In the case of polyamide fiber, polyester fiber, and cotton, those of about 5 to 10 mm are used. The addition amount is 10 to 40 parts by mass with respect to 100 parts by mass of rubber.
[0022]
Furthermore, a softener, a reinforcing agent composed of carbon black, a filler, an anti-aging agent, a vulcanization accelerator, a vulcanizing agent, and the like are added to the rubber.
[0023]
Examples of the softening agent include general rubber plasticizers, such as phthalates such as dibutyl phthalate (DBP) and dioctyl phthalate (DOP), adipates such as dioctyl adipate (DOA), and dioctyl sebacate (DOS). Sebacates, phosphates such as tricresyl phosphate, etc., or general petroleum softeners are included.
[0024]
Next, as shown in FIG. 1, the laminate 14 in which the short fiber oriented rubber sheet 20 and the nonwoven fabric 16 are bonded is formed so that a certain void is formed inside the inner mold 41 of the belt vulcanizer 40 and the outer mold 46. Place on the base. Since the inner mold 41 is moved from another molding process, the medium distribution port A and the medium feeding / discharging path B are separated. After the inner mold 41 is placed on the base, the medium distribution port A is Connect to the pipe with joint J.
[0025]
The nonwoven fabric 16 used here is made of a fiber such as polyethylene, polypropylene, polyamide, polyester, acrylic, glass fiber, etc. having a length of 5 to 60 mm. For example, the fibers in the web are entangled and entangled by mechanical action. It is formed by a needle punch or the like that generates strength and is not treated with a binder. The basis weight of the nonwoven fabric is preferably ²⁰ to 100 g / m ² .
[0026]
The medium feeding machine is operated to feed the flexible jacket 42 through the medium feeding / discharge path B and the medium circulation port A such as high-pressure air. Since the upper and lower portions of the flexible jacket 42 are hermetically fixed on the inner mold 41, air is filled between the inner surface of the flexible jacket 42 and the outer surface of the inner mold 41. It gradually expands. Then, the short fiber oriented rubber sheet 20 mounted on the outer peripheral surface thereof is uniformly expanded in the radial direction and heated to 100 to 160 ° C. with a heater or high-temperature steam and the rib mold 45 of the outer mold 46 and 30 to 120 seconds. Make contact.
[0027]
At this time, the short fiber oriented rubber sheet 20 is pressed against the rib mold 45 of the outer mold 46 by the expansion pressing force of the flexible jacket 42, and an unvulcanized having a plurality of V-shaped protrusions on the surface as shown in FIG. The preformed body 21 is formed.
[0028]
After that, the valve is switched to the vacuum pump, the air filled in the flexible jacket 42 is exhausted, and then the flexible jacket 42 is contracted and returned to the original position shown in FIG. .
[0029]
Then, the inner mold 41 is extracted from the outer mold 46, and a reinforcing cloth 47 and a cord 48 made of a cord are sequentially wound around the outer peripheral surface of the flexible jacket 42 of the inner mold 41. Thereafter, after the inner die 41 is installed in the outer die 46 as shown in FIG. 3, the flexible jacket 42 is expanded as shown in FIG. 4, and the reinforcing cloth 47 and the core wire 48 are made uniform in the radial direction. The belt sleeve 51 is produced by inflating and intimately vulcanizing the preformed body 21 attached to the rib mold 45 of the outer mold 46 heated to 100 to 180 ° C. with a heater or high temperature steam. By molding the unvulcanized preform 21 as in the above manufacturing method, the extension amount of the core wire 48 due to the expansion of the flexible jacket 42 can be suppressed at the time of molding, and the core wire 48 can be arranged flatly. A V-ribbed belt excellent in stability can be produced.
[0030]
After vulcanization, the flexible jacket 42 is contracted as shown in FIG. 5 and the inner mold 41 is extracted from the outer mold 46, and then the vulcanized belt sleeve 51 attached to the outer mold 46 is extracted.
[0031]
In order to polish and surface-treat the rib portion surface of the vulcanized belt sleeve 51, the belt sleeve 51 is stretched around two axes of the main shaft 55 and the driven shaft 56 as shown in FIG. The rib wheel surface 62 is rotated to a thickness of about 0.05 to 0.1 mm by abutting a polishing wheel 57 electrodeposited with diamond, whereby the nonwoven staple fibers adhering to the rib surface 62 are raised.
[0032]
Then, the vulcanized belt sleeve 51 is inserted into another one- or two-axis drum and rotated while being cut into a predetermined width in the circumferential direction. A plurality of V-ribbed belts 1 in which the shaped ribs are accurately formed are obtained.
[0033]
FIG. 7 is a cross-sectional perspective view of the obtained V-ribbed belt. The V-ribbed belt 100 has a cord 102 made of a cord having high strength and low elongation embedded in an adhesive rubber layer 103, and has a compression rubber layer 104 as an elastic body layer below the cord. This compressed rubber layer 104 is provided with a plurality of rib portions 106 having a substantially triangular cross section extending in the longitudinal direction of the belt, and short fibers 109 are arranged in a wave shape on the inner layer 110 of the rib portion to improve the lateral pressure resistance of the belt. Short fibers 108 randomly raised from the nonwoven fabric 107 attached to the surface layer 111 of the rib portion are dispersed, and the short fibers 108 are in a state of covering the surface of the rib portion.
[0034]
The rubber used for the adhesive rubber layer 103 is similar to the rubber compound of the compressed rubber layer 104 excluding short fibers. Of course, short fibers may be included.
[0035]
As the core wire 102, a polyester fiber, an aramid fiber, and a glass fiber are used. Among them, the total number of deniers obtained by twisting together polyester fiber filaments having ethylene-2,6-naphthalate as a main constituent unit is 4,000 to 8, A cord subjected to adhesion treatment of 000 is preferable because the belt slip ratio can be kept low and the life of the belt is extended. Further, the core wire 102 is subjected to an adhesion treatment for the purpose of improving the adhesion to rubber. As such an adhesion treatment, it is common to immerse the fiber in a resorcin-formalin-latex (RFL) solution and then heat-dry to form a uniform adhesion layer on the surface. However, the present invention is not limited to this, and there is also a method of performing a pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.
[0036]
The core wire 102 can be finished into a belt having a high modulus by setting the spinning pitch, that is, the winding pitch of the core wire to 0.9 to 1.3 mm. If it is less than 0.9 mm, the cord cannot ride on the adjacent cord and cannot be wound, while if it exceeds 1.3 mm, the modulus of the belt gradually decreases.
[0037]
The back reinforcing material 105 is selected from a woven fabric, a knitted fabric, a non-woven fabric fiber material, or a rubber material, more preferably a non-woven fabric. Examples of the constituent fiber material include natural fibers such as cotton, hemp, and rayon, and organic fibers such as polyamide, polyester, polyethylene, polyurethane, polystyrene, polyfluoroethylene, polyacryl, polyvinyl alcohol, wholly aromatic polyester, and aramid. Can be mentioned. The above canvas is immersed in a resorcin-formalin-latex liquid (RFL liquid) according to a known technique and then subjected to friction by rubbing unvulcanized rubber against the back reinforcing material 105, or soaked in rubber after being immersed in RFL liquid. Immerse in the liquid.
[0038]
In the V-ribbed belt thus obtained, the short fibers 108 raised from the nonwoven fabric 107 on the rib portion surface 111 reduce noise during belt running, and further prevent the occurrence of cracks from the rib portion surface.
[0039]
【The invention's effect】
As described above, in the method for manufacturing a transmission belt according to the claims of the present application, it becomes possible to accurately mold the rib portion of the vulcanized belt sleeve using a laminate of a rubber sheet and a nonwoven fabric, and the surface of the rib portion is polished. By doing so, it is possible to raise a part of the non-woven fabric short fibers, thereby providing a transmission belt with reduced noise during running of the belt.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a state in which a preform is molded.
FIG. 2 is a cross-sectional view of a state after producing a preform.
FIG. 3 is a cross-sectional view of a state before producing an unvulcanized belt sleeve.
FIG. 4 is a cross-sectional view of a state in which a belt sleeve is vulcanized.
FIG. 5 is a cross-sectional view of the belt sleeve after vulcanization.
FIG. 6 is a view showing a state where the rib surface of the belt sleeve is being polished.
FIG. 7 is a cross-sectional perspective view of a V-ribbed belt obtained by the manufacturing method of the present invention.
[Explanation of symbols]
14 Laminate 16 Nonwoven fabric 20 Rubber sheet 21 Preliminary molded body 41 Inner mold 42 Flexible jacket 46 Outer mold 48 Core wire 100 V-ribbed belt 102 Core wire 103 Adhesive rubber layer 104 Compressed rubber layer 106 Rib portion 107 Nonwoven fabric 108 Brushed short fiber 111 Rib surface

Claims (3)

In a method of manufacturing a transmission belt having a rubber layer in which a core wire is embedded along the belt longitudinal direction and a rib portion extending in the longitudinal direction of the belt adjacent to the rubber layer,
Between the inner mold with a flexible jacket on the outer peripheral surface and the outer mold engraved with a rib mold on the inner peripheral surface, a laminate of a rubber sheet and a nonwoven fabric is interposed,
An unvulcanized preform is prepared by inflating the flexible jacket so that the nonwoven fabric of the laminate is in close contact with the stamped rib mold of the outer mold,
Wrap at least the core wire around the inner flexible jacket surface separated from the outer mold,
Again, the inner mold is installed in the outer mold, the flexible jacket is expanded, and the core wire is vulcanized integrally with the preform molded on the outer mold,
Demold to produce a vulcanized belt sleeve with ribs,
A method for producing a transmission belt, characterized in that the surface of the rib portion of the vulcanized belt sleeve is polished to raise short fibers of a nonwoven fabric. In the laminate of the rubber sheet and the nonwoven fabric manufacturing method of the driving belt according to claim 1, wherein the rubber sheet contains a short oriented fibers. In the laminate of the rubber sheet and the nonwoven fabric manufacturing method of the driving belt according to claim 1, wherein the rubber sheet contains no short fibers.

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