JPH0737082B2 - Manufacturing method of center belt for high load transmission belt - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high load transmission belt in which a hard block body is fitted and fixed to each tooth of a center belt made of an elastomer and having a plurality of upper and lower teeth. Specifically, it relates to a manufacturing process of a center belt used for a high load transmission belt.

(Prior Art) Conventionally, a center belt for a high load transmission belt of this type is manufactured by a method similar to that of a double timing belt. For example, as described in Japanese Patent Publication No. 46-22101, a grooved inner mold is used. Then, a canvas, a tension rope, an unvulcanized rubber layer, and a canvas are sequentially laminated and wound, and a cylindrical rubber mold having a groove is inserted on the outer surface thereof, and then the rubber layer is pressure-vulcanized to form an inner mold. As described in the method of forming upper and lower double teeth by press-fitting into the groove portion of the mother die and Japanese Patent Laid-Open No. 49-135056, a premolded unvulcanized rubber sheet preformed in the grooved inner mold. There is a method in which the tensile strength rope is spirally wound, and the same typed and unvulcanized rubber sheets are laminated as described above, a grooved mother die is provided, and then vulcanization is performed.

(Problems to be Solved by the Invention) However, in any of the methods, since the mother die is used to form the upper teeth, the positions of the upper and lower teeth may be displaced, resulting in an uneven arrangement. Further, these methods are not economical because it is necessary to use a mother die used for vulcanization molding according to the size of the belt.

Furthermore, in order to use it as a double timing belt, the arrangement of the upper and lower teeth and the PLD must be made uniform, and the uniformization of the PLD was taken into consideration. When used as the center belt of the load transmission belt, it was not necessary to make the PLD uniform with high precision, which was a waste of work.

In order to solve the above problems, the present invention has the same arrangement of upper and lower teeth, does not need to change the mother die for vulcanization molding of belt sleeves of all sizes, and has a high load that does not require labor. An object of the present invention is to provide a method for manufacturing a center belt for a power transmission belt.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a belt-shaped projection in the outer peripheral axial direction in a method of manufacturing a center belt for a high load transmission belt having a plurality of teeth on both sides at a predetermined pitch. Between a pair of cylindrical toothed drums with adjustable inter-axis distances in which concave grooves are alternately formed, a belt sleeve having a plurality of teeth at a predetermined pitch is wound around one side that has already been molded and vulcanized to apply tension, and Sheets laminated with vulcanized rubber and elastic canvas are sequentially laminated with the unvulcanized rubber side on the back side of the belt sleeve, and the tooth profile consisting of the upper plate and the lower plate is placed between the pair of toothed cylindrical toothed drums. Nip and press to vulcanize the back side teeth, then remove each die from the belt sleeve and rotate the belt sleeve, vulcanize the next tooth forming shape in the same way, repeat the above process Endless high load transmission A center belt sleeve for a high load transmission belt is obtained by cutting the center belt sleeve for a belt and cutting the belt into a predetermined width in the longitudinal direction of the belt sleeve.

(Operation) According to the manufacturing method of the present invention, since the step of vulcanizing and molding the upper teeth is performed on the upper plate and the lower plate with the tooth profile, it is extremely unlikely that the upper and lower teeth are displaced. Since the distance between the two drums on which the belt sleeve is hung during molding can be changed, it is possible to hang a belt sleeve of any size. In addition, the belt sleeve is pre-vulcanized and has teeth on one side, and the unvulcanized rubber sheet is overlaid on the back side of the belt sleeve for vulcanization molding. It doesn't take much time.

Hereinafter, the details of the present invention will be described with reference to the accompanying drawings.

(Example) A method for manufacturing a center belt for a high load transmission belt of the present invention comprises laminating an unvulcanized rubber sheet obtained by laminating a stretchable canvas on the other surface of a belt sleeve having teeth on one surface already vulcanized and molded, It is vulcanized and molded.

As shown in FIG. 5, a stretchable canvas 10 with unvulcanized rubber is provided on the tooth surface, and a low elongation and high tensile strength made of glass fiber, aromatic polyamide fiber, polyester fiber, steel wire, etc. inside. A vulcanized product 1 of a belt sleeve having a body rope 11 embedded therein and having teeth with a predetermined pitch on only one side is prepared.
This belt sleeve 1 is made by endlessly winding a stretchable canvas with unvulcanized rubber on the outer peripheral surface of a cylindrical toothed mold having a tooth profile, then spirally wrapping a tension rope under a constant tension, and then wrapping the An unvulcanized rubber sheet having a required constant thickness and having a volume for forming teeth is wrapped around and vulcanized and molded by heating and pressing.

Further, as shown in FIG. 1, the belt sleeve 1 is hung between two cylindrical toothed drums 2 and 3 which have teeth with the same pitch as the teeth of the belt sleeve and which are arranged so that the axial distance can be adjusted. Apply tension. The cylindrical toothed drums 2, 3
The unvulcanized rubber sheet 5 in which the stretchable canvas with unvulcanized rubber is overlaid is arranged on the back surface of the belt sleeve 1 from the side of one of the drums 3. After that, the portion where the unvulcanized rubber sheet 5 formed on the back surface of the belt sleeve 1 is arranged is sandwiched between the drums 2 and 3 by a press die including an upper plate 6 and a lower plate 7 and heat-vulcanized. As shown in FIG. 2, the press die made up of the upper plate 6 and the lower plate 7 has knock pins N, N at the diagonal positions on both ends of the lower plate 7, while the upper plate 6 has pin insertions at positions opposite to the pins N, N. Holes N ′ and N ′ are formed, and when the upper plate 6 and the lower plate 7 are combined, the knock pins N and N are inserted and fitted into the pin insertion holes N ′ and N ′ so that the upper and lower positions of the belt can be adjusted. The upper and lower tooth portions are accurately and uniformly arranged.
After the lower plate 6 and the upper plate 7 of the press die are fitted to the tooth portions of the vulcanized tooth forming body as described above, the upper plate 6 and the lower plate 7 facing each other having the above-described structure are fitted with knock pins N, N and pin insertion holes. N ',
N'is inserted and fitted to each other to sandwich the unvulcanized rubber sheet 5 and the elastic canvas with unvulcanized rubber, and then a heating mechanism such as steam and an electric heater is provided inside and a cooling mechanism C on both sides. , Upper and lower heating presses K, K '
Is vulcanized by applying pressure in the direction of the arrow in FIG. This vulcanization is usually carried out by pressurizing with a heating press K on the upper plate 6 and a cooling plate K'under the lower plate 7 as shown in FIG. It is narrower than the bottom board 7. By making the width narrow, excess rubber flows out to the side of the press die to make the belt thickness uniform. The cooling plate K'is not always necessary.

Then, during vulcanization, the unvulcanized rubber sheet 5 is in a fluid state, and at the same time, the tooth portion of the tooth-formed unvulcanized rubber sheet 5 is fitted into the groove of the upper plate 6 while stretching the elastic canvas with unvulcanized rubber. Then, the belt sleeve 1 and the unvulcanized rubber sheet 5 are heated and pressed by narrowing the space between the upper and lower plates so that the knock pins and the pin insertion holes of the upper plate 6 and the lower plate 7 fit into each other. Further, the vulcanized portion and the vulcanized portion are still vulcanized by the cooling mechanism provided on both sides of the upper and lower heating presses and the cooling plate sandwiched between the press die and the press die (the cooling mechanism circulates cooling water inside). You can make the boundary of the part that is not clear more clearly.

After the molding and vulcanization of the upper teeth in this way, the respective press dies are removed from the belt sleeves, and the belt sleeves partially formed with upper and lower double teeth are obtained. Then, the toothed pulley first
Rotate in the direction of the arrow in the figure to move the position of the belt sleeve to the left in the figure, and then stack the unvulcanized rubber sheet 5 and stretchable canvas with unvulcanized rubber on the back surface of the next unmolded portion in the same manner as above. The upper plate 6 and the lower plate 7 are pressed from above and below by a heating press to sandwich and press the laminated portion to continuously form upper teeth on the back surface of the belt to form a wide endless vulcanized center belt sleeve.

Then, the vulcanized center belt sleeve obtained as described above is subsequently cut in a predetermined width in the longitudinal direction, so that the upper and lower surfaces of the tensile member 11 as shown in FIG. A center belt for a high load transmission belt can be obtained.

Further, as another embodiment, unlike the above-mentioned embodiment, the molding drums 4 are arranged on both the left and right drums 2 and 3, and the unvulcanized rubber sheets 5 are overlapped on the upper and lower sides to form the left and right drums 2, 3. One example is one in which the upper and lower linear portions of the belt sleeve between 3 are provided with metal molds 6 and 7 having a tooth profile and a heating and pressing press K, and both sides are vulcanized at once. By using such an apparatus, molding and vulcanization can be performed at a speed twice as fast as that in the above-mentioned embodiment.

(Effect) According to the method for manufacturing a center belt for a high load transmission belt of the present invention, an unvulcanized rubber sheet and an elastic canvas with unvulcanized rubber are sequentially formed on the back surface of the sleeve of the belt having teeth on one side that has been previously vulcanized. The upper teeth are formed by pasting them together while sandwiching them between the toothed drums, and the molded parts are fitted and sandwiched by a pair of grooved press dies equipped with knock pins and pin insertion holes, and heated from outside. Then, the obtained belt sleeve is cut into a predetermined width, and the upper tooth vulcanizing step is performed with a grooved press die having knock pins and pin insertion holes, so the positions of the upper and lower teeth The center belt used for the high load transmission belt has the same shape as the double timing, but it is not necessary to align the belt PLD with high precision, and the conventional double timing belt is manufactured. The belt sleeve formed by molding only the lower teeth, which was used in the above, is not left in the semi-vulcanized state to adjust the thickness when forming the upper teeth, and the completely vulcanized belt sleeve is used, so the sleeve is easy to handle. Yes, the process can be simplified and the cost can be reduced. Further, since a mold is not required in the molding and vulcanizing step of the upper teeth, it is not necessary to prepare a mold of each size.

[Brief description of drawings]

FIG. 1 is a front view showing one step of the manufacturing method of the present invention, and FIG.
FIG. 3 is a perspective view of a toothed mold, FIG. 3 is a front view showing a vulcanizing portion when a cooling plate is provided on the lower mold, and FIG. 4 is a side view of a center belt manufactured by the manufacturing method of the present invention. Figure, fifth
The figure is a side view of the main part of the belt sleeve before the upper teeth are provided. 1 ... Belt sleeve with one tooth 2, 3 ... Cylindrical drum 4 ... Molding drum 5 ... Unvulcanized rubber sheet 6 ... Upper plate 7 ... Lower plate K ... Heating / pressing press K '... Cooling Pressing press N ... Dowel pin N '... Pin insertion hole C, C' ... Cooling mechanism

Claims (1)

[Claims] 1. A method of manufacturing a center belt for a high load transmission belt having a plurality of teeth on both sides at a predetermined pitch, wherein a pair of cylinders having an axial distance adjustable by alternately forming band-shaped projections and concave grooves in an outer peripheral axial direction. A belt sleeve having a plurality of teeth at a predetermined pitch is wound around one side that has already been molded and vulcanized between toothed drums to apply tension, and a sheet in which unvulcanized rubber and elastic canvas are laminated is belted with the unvulcanized rubber side. Sequentially stacked so as to contact the back side of the sleeve, sandwiched between the pair of cylindrical toothed drums with a press die with a tooth profile consisting of an upper plate and a lower plate to vulcanize the rear tooth portion, After that, each press die is removed from the belt sleeve, the belt sleeve is rotated to vulcanize the next tooth forming profile in the same manner, and the above steps are repeated to obtain an endless high load transmission belt belt sleeve,
A method for manufacturing a center belt for a high load transmission belt, further comprising cutting this into a predetermined width in a belt sleeve longitudinal direction to form a plurality of center belts for a high load transmission belt.