JP4648012B2 - Manufacturing method of rubber molded body for belt - Google Patents

Description

  The present invention relates to a method for producing a rubber molded body for a belt, and more specifically, an unvulcanized belt rubber molded body used as a molded member when producing a low edge cog belt, that is, a cog crest portion with a constant or irregular pitch. The present invention relates to a method for producing a rubber molded body for a belt that can accurately and quickly cut a cog crest portion of a rubber molded body having a cog valley.

  Today, the low edge cog belt is typically produced by a preform method or a spancog method. In this pre-form manufacturing method, a cog pad molded in a cog shape is formed by placing a base cloth and an unvulcanized rubber sheet in a mold having alternating teeth and grooves and pressurizing the cog pad. The belt is endlessly fitted by fitting it into a cylindrical matrix mounted on a molding drum, butting both ends of the cog pad together.

The cog pad is a laminate of a lower cloth and an unvulcanized rubber sheet, and has cog crests and cog troughs alternately at a constant pitch in the length direction.
Conventionally, the cutting of the cog pad has been performed manually by a skilled worker. That is, the operator counts the number of cogs in advance according to the belt circumference, marks the cog mountain to be cut with chalk, and then cuts one cog mountain (the top of the cog) with a cutter, Moreover, the other cog mountain part was cut | disconnected similarly.

Further, a cutting apparatus that performs this cutting work on behalf of a skilled worker has been developed and disclosed in Patent Document 1.
JP 7-32291 A

  The most important thing in this cutting operation is to cut the top of the cog crest straight in the width direction and in the thickness direction in a biased manner, and to join both ends of the cut cog pad in a straight line. However, there are many cases where the cog is cut off from the cog crest, and both ends of the cog pad cannot be jointed straightly and joints are created. The volume increased easily and a defect occurred in the joint.

  As a result, in the obtained belt, as shown in FIG. 8, a volume crack occurs in which the volume of the cog crest C having the joint portion J becomes smaller than that of the other cog trough C, and vice versa. Thus, the volume increase that the volume of the cog valley portion C having the joint portion J becomes larger in the other cog mountain portion C may occur. When a belt having a cog crest having a different volume is caused to travel, there is a risk that a crack may occur from the joint due to load fluctuation or heat generation during traveling.

  Further, even during the cutting operation of the cog pad, since the cutting operation was performed with the cog mountain portion as the upper surface, the adhesive rubber layer was likely to adhere to the work table, and the workability was considerably poor.

  The present invention pays attention to such a problem, and can cut a cog crest portion of a rubber molded body such as a cog pad straightly, quickly and accurately without depending on a skilled worker, and form an accurate joint portion. It aims at providing the manufacturing method of the rubber molding for belts.

That is, in the invention according to claim 1 of the present application, a rubber molded body having a cog crest portion and a cog trough portion alternately in the longitudinal direction is formed, and the different cog crest portions provided on the rubber molded body intersect in the longitudinal direction. In a method for producing a rubber molded body for a belt cut into a predetermined length ,
After laminating a reinforcing cloth and an unvulcanized rubber sheet on a cogged mold having alternating ridges and ridges, pressure molding is performed to form a rubber molded body having cog ridges and cog valleys alternately. ,
The rubber molded body is placed on the base so that the cog mountain portion faces the back side, and a pair of holding molds having a concave portion and a convex portion are formed. The concave portion and the convex portion are the cog mountain portion and the cog valley portion of the rubber molded body. And placed on the base in a separated state so as to face each other at the top of the Cog mountain ,
After pressing the holding member provided with a slit to accommodate the cutter against the back of the rubber molded body, the cutter is accommodated in the gap of the holding mold and the slit of the holding member and moved in the width direction of the rubber molded body . Cut the mountain at its center ,
Furthermore, the rubber molded body is moved by a predetermined length, and another cog crest portion is cut at the central portion in the same manner as described above.

  In this way, a pair of holding molds are fitted into the cog crest and cog valley of the rubber molded body, and the rubber molded body with the adhesive rubber layer laminated on the back is placed on the base so that the cog crest is directed to the back side. Therefore, the rubber molded body can be prevented from sticking to the base surface, the installation work can be facilitated, the rubber molded body can be stably installed, and the cutter is held between the holding mold gap and the holding member. Since the cog crest is cut while being moved linearly in the width direction of the rubber molded body, the backlash of the cutter is eliminated and the cutting accuracy of the cog crest is improved. Since the body is installed on the base such that the cog mountain portion faces the back side, adhesion of the rubber molded body to the base surface can be prevented.

  Moreover, in the present invention, when the cut surfaces at both ends are abutted, joints can be made at the center of the cog mountain at any location in the width direction, and even when finished to a belt, volume cracking and volume increase of the cog mountain do not occur, And cracks from the joints are difficult to enter.

  The invention described in claim 2 uses a heated cutter, which facilitates cutting of the rubber molded body.

In the manufacturing method of the present claimed belt rubber molded body as described above, the installation work can prevent sticking to the base surface of the rubber molding is facilitated, its central portion a cog crest portion of the rubber molding In order to cut the rubber molded body by a predetermined length and cut the other cog crests at the central part in the same manner as described above, if the cut surfaces at both ends are brought into contact with each other, the cog crests at any location in the width direction It can be jointed at the center of the part, and even when finished into a belt, there is no effect of volume cracking or volume increase at the cog mountain, and cracks from the joint part are also difficult to enter.

  Furthermore, when a heated cutter is used, the rubber molded body can be easily cut.

Hereinafter, the method for cutting a rubber molded body of the present invention will be described in detail.
FIG. 1 is a view showing a production state of a cog pad 10 which is a rubber molded body. A flat cogged die 4 having alternating ridges 2 and ridges 3 is prepared, and a reinforcing cloth is provided on the cog die 4. 5 and the unvulcanized rubber sheet 6 are laminated, and then pressed with a press plate under conditions set to a predetermined temperature of 40 to 100 ° C., and molded to form a cog crest 11 and a cog trough shown in FIG. The cog pad 10 having 12 alternately along the longitudinal direction is produced.
The unvulcanized rubber sheet 6 can be used by laminating a rubber sheet forming a compression rubber layer and an adhesive rubber layer of the belt.

  The rubber of the unvulcanized rubber sheet 6 is 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. A rubber material such as a polymer mixed with a metal salt alone or a mixture thereof is used.

The unvulcanized rubber sheet 6 is made of fibers such as aramid fiber, polyamide fiber, polyester fiber, cotton, etc., and the length of the fiber varies depending on the type of fiber, but short fibers of about 1 to 10 mm are used. About 3 to 5 mm for aramid fibers, about 5 to 10 mm for polyamide fibers, polyester fibers, and cotton are used. And the direction of the short fibers in the rubber layer is oriented within the range of 70 ° to 110 ° when most of the short fibers are oriented 90 ° to the longitudinal direction of the belt. It is desirable.
The short fiber may be included in the unvulcanized rubber sheet to be the adhesive rubber layer, but it is preferably not included.

  The reinforcing cloth 5 is made of cotton, polyester fiber, aramid fiber, nylon or the like, and is a cloth woven in plain weave, twill weave, satin weave, etc., and may be a wide angle canvas in which the crossing angle between the warp and weft is about 90 to 120 °. The reinforcing cloth 5 is subjected to RFL treatment, and then the rubber composition is subjected to fiction and coaching to obtain a canvas with rubber. The RFL liquid is obtained by mixing an initial condensate of resorcin and formalin into a latex. Examples of the latex used here include chloroprene, styrene / butadiene / vinylpyridine terpolymer, and hydrogenated nitrile rubber (H-NBR). , NBR, etc.

  The cog pad 10 obtained in this way is cut at the cog crest by the method shown in FIGS. First, the flat base 15 on which the cog pad 10 is installed is separated into two with a predetermined gap d, and holding molds 17 having convex portions 18 and concave portions 19 alternately are provided on the side walls of the bases 15 and 15. They are fixed opposite each other along the width direction. The holding molds 17 and 17 facing each other have an interval l so that the cutter 20 can be inserted. A heating device may be attached to the base 15 so that the cog pad 10 can be heated to easily cut the cog mountain portion.

  When the cog pad 10 is installed on the flat base 15 so that the cog mountain portion 11 faces the back side, the recessed portion 19 and the convex portion 18 of the pair of holding molds 17 and 17 are separated from the cog mountain portion 11 and the cog valley of the cog pad 10. Since the cog pad 10 is accurately fixed by being fitted to the portion 12 and the adhesive rubber layer is located on the back side, the installation work of the cog pad 10 on the base 15 is facilitated.

The holding member 22 provided with the slit 23 for accommodating the cutter 20 is lowered by the operation of the cylinder, and the back surface 24 of the cog pad 10 is pressed. At this time, the slit 23 of the pressing member 22 is set on the extended line of the gap 1 between the holding dies 17 and 17. The pressing force of the pressing member 22 is preferably 0.1 to 0.5 kg / cm ² .

The cutter 20 is located below the holding dies 17, 17, and protrudes about 10 to 30 mm from the bottom surface of the recess 19 of the holding dies 17, 17 during rubber cutting, and is accommodated in the slit 23. The cutter 20 that has jumped out moves in the width direction of the cog pad 10, cuts the central part of the cog mountain portion 11 vertically while being accommodated in the slit 23, and then returns to the original position. The slit 23 accurately cuts the cog crest portion 11 without the rattling of the cutter 20 being moved. Further, the cog pad 10 is moved by a predetermined length, and the central part of the other cog mountain portion 11 is cut vertically in the same manner as described above.
Moreover, a heating device can also be attached to the cutter 20, and the cutter 20 can be heated to 60 to 80 ° C. to easily cut the cog mountain portion.

The cog pad 10 cut to a predetermined length is used when manufacturing a belt. Below, the manufacturing method of the belt which uses the cog pad 10 is demonstrated.
As shown in FIG. 5, a grooved mold 45 having teeth 43 and grooves 44 alternately is mounted on a molding machine (not shown), and the cut surface 40 is formed while fitting the cog crest 11 to the grooves 44. The joint part 45 is formed by butting.

As shown in FIG. 6, the core 7 is wound around a spiral, and a laminate of an unvulcanized rubber sheet 46 of the stretched rubber layer and one to several reinforcing cloths 5 is wound around the core 7 to produce a molded body 47. . Of course, in this embodiment, instead of the grooved mold 45 having the tooth portions 43 and the groove portions 44 alternately, an inner matrix made of vulcanized rubber provided with groove portions at predetermined intervals along the circumferential direction is mounted. A molded mold can also be used.
In this embodiment, a grooved mold 45 taken out from the molding machine is placed on a support base, and a mother die made of vulcanized rubber having concave portions provided at predetermined intervals along the circumferential direction ( Insert a jacket (not shown) and a jacket (not shown).

  The molded body 47 is transferred to a vulcanizing can and vulcanized by an ordinary method. After vulcanization, the jacket, the mother die, and then the cylindrical sleeve are extracted from the grooved mold 45, and the sleeve is cut into a predetermined width to finish a power transmission belt 50 as shown in FIG.

  In the obtained power transmission belt 50, a core wire 7 made of a cord such as polyester fiber, aramid fiber, or glass fiber is embedded in the adhesive rubber layer 51, and the reinforcing cloth 5 and the rubber layer are disposed on the adhesive rubber layer 51. There is a stretched rubber layer 52 in which the reinforcing fabric 5 and the rubber layer are similarly laminated. The compressed rubber layer 53 has the cog valley portions 12 and the cog mountain portions 11 alternately along the longitudinal direction of the belt at a constant pitch.

  In the cog mountain portion 11 shown in FIG. 7, the joint portion 45 exists in the region of the cog mountain portion 11, the angle with the core line becomes a right angle, and the joint portion 45 is a vertical surface. Although it is easy for the rubber to flow into the joint portion 45, this flow is only the cog mountain portion 11 and does not penetrate deeply, so that the bending fatigue property is not greatly affected.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a method of manufacturing a transmission belt having a cog portion such as a low edge single cogged belt and a low edge double cogged belt used as a snowmobile, scooter, and general industrial transmission belt.

It is a perspective view which shows the preparation state of the cog pad which concerns on this invention. It is a front view of the cog pad obtained by the method shown in FIG. It is a figure which shows the state which cut | disconnects the cog mountain part of the cog pad which concerns on this invention. It is the figure seen from the AA direction of FIG. It is an enlarged view which shows the place which joined the cog pad which concerns on this invention. It is a figure which shows the state which is producing the belt molded object using a cog pad. It is a partial front view of the power transmission belt. It is a partial front view of the belt for power transmission in which the cog mountain part has caused the volume crack. It is a partial front view of the belt for power transmission in which the cog mountain part raises the volume.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cog pad 11 Cog mountain part 12 Cog valley part 15 Base 17 Holding type 18 Concave part 19 Convex part 20 Cutter 22 Presser member 23 Slit 40 Cutting surface 45 Joint part

Claims (2)

For belts in which a rubber molded body having alternating cog ridges and cog valleys along the longitudinal direction is formed, and the different cog ridges provided on this are cut in the width direction intersecting the longitudinal direction to a predetermined length In the method for producing a rubber molded body,
After laminating a reinforcing cloth and an unvulcanized rubber sheet on a cogged mold having alternating ridges and ridges, pressure molding is performed to form a rubber molded body having cog ridges and cog valleys alternately. ,
The rubber molded body is placed on the base so that the cog mountain portion faces the back side, and a pair of holding molds having a concave portion and a convex portion are formed. The concave portion and the convex portion are the cog mountain portion and the cog valley portion of the rubber molded body. And placed on the base in a separated state so as to face each other at the top of the Cog mountain ,
After pressing the holding member provided with a slit to accommodate the cutter against the back of the rubber molded body, the cutter is accommodated in the gap of the holding mold and the slit of the holding member and moved in the width direction of the rubber molded body . Cut the mountain at its center ,
Further, the rubber molded body is moved by a predetermined length, and the other cog mountain portion is cut at the central portion in the same manner as described above.
A method for producing a rubber molded body for a belt,   The manufacturing method of the rubber molded object for belts of Claim 1 which uses the heated cutter.

Images