JPS63236630A - Manufacture of power transmitting v belt - Google Patents

Abstract

PURPOSE:To improve the uniformity of the line up of ropes and shrinkage stress by setting an unvulcanized belt formed body with its rear surface side kept inside, and vulcanizing it, when the lapped type V belt using tensile resisting ropes is vulcanized in a ring mold. CONSTITUTION:An unvulcanized rubber sheet 3, tension resisting ropes 4 and an unvulcanized rubber sheet 6 are wound on the outer peripheral surface of a cylindrical drum (d), thereby constituting a wide unvulcanized formed body. After said formed body has been cut at a constant width, it is removed from the drum, and its both sides are cut into an inverted trapezoid shape, and then its outer peripheral surface is covered with one or several bias cover canvas with rubber. Thus, the unvulcanized belt formed body 8 is made. Next, the unvulcanized belt formed body 8 is turned over and inserted into the cylindrical ring mold M on which a plurality of trapezoid grooves G are graved in width direction of the outer peripheral surface of the mold, and further into said, outer peripheral surface, a cylindrical elastic rubber sleeve 11 is fitted. The rubber sleeve is vulcanized at prescribed temperature and pressure, and in prescribed time. After the vulcanization of the belt has been finished, the belt is removed from the ring mold and is again turned over, whereby the lapped V belt 12 whose bottom 10 is bulged to rear surface side, is molded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a V-belt for power transmission, and in particular to a method for manufacturing a V-belt for power transmission, in particular a method for manufacturing a wrap-type V-belt having a tensile rope with high shrinkage stress in a ring mold. It is about the method.

(Prior art) Conventionally, as methods for curing wrap-type V-belts, the ring mold vulcanization method is generally used for relatively short V-belts, and the press vulcanization method is used for other long belts. well known.

In the ring mold vulcanization method, as shown in Fig. 7, an unvulcanized belt (8
) is set with the back side facing the outside of the ring mold, a cylindrical rubber sleeve (11) is fitted around the ring mold, and vulcanization is performed. In general, wrapped V-belts whose outer circumferential surface is covered with cover canvas use a tensile rope with lower shrinkage stress than low edge type belts which have cover canvas only on the top and bottom surfaces of the belt. Even with the above-mentioned normal vulcanization method, a product with sufficiently uniform rope alignment was obtained. However, on the other hand, the lap type belt is
There is a problem that the belt elongates significantly during running, causing slippage during use and a reduction in transmission capacity, and there is a need to reduce the elongation of the belt. One known method for reducing belt elongation is to use a tensile rope with high shrinkage stress, which is 1.5 times stronger for low edge type belts than for lap type belts. Ropes with high shrinkage stress are used.

(Problems to be Solved by the Invention) However, when a lap belt using a rope with high shrinkage stress is vulcanized in a ring mold, the following problems occur.

(1) If a tensile rope with high shrinkage stress is used, the tensile rope will shrink due to the heat during vulcanization, and the unvulcanized rubber sheet (
The compressed rubber layer) exhibits a fluid state, and due to the pressing force flowing into the inverted trapezoidal groove of the mold, the tensile rope falls into the compressed rubber layer, making it impossible to obtain good rope alignment.

(2) In order to prevent the rope from falling as described in (1) above, the flexibility of the pressure decreases and the flexibility deteriorates.

In view of the various circumstances of the conventional method, the present invention was achieved as a result of various studies to solve the problems, and it is possible to uniformly arrange the ropes using a tensile rope with high shrinkage stress. The object of the present invention is to obtain a method for manufacturing a lap belt that has little elongation during running.

(Means for Solving the Problems) In order to achieve this objective, the method for manufacturing the power transmission belt of the present invention includes the following steps A, B, and C. : Characterized by sequential implementation.

That is, an unvulcanized rubber sheet, a tensile rope, and an unvulcanized rubber sheet are sequentially laminated and pasted on the outer peripheral surface of a cylindrical drum to form a wide cylindrical unvulcanized molded body, and the circumference is After cutting with a certain width in the direction, remove it from the drum, skive both sides of the unvulcanized molded product into an inverted trapezoid shape at a predetermined angle, and cover it with a bias cover canvas with rubber to form an unvulcanized belt molded product. (b) Step B of fitting a large number of trapezoidal grooves with a constant pitch in the width direction of the outer circumferential surface around the g and vulcanizing at a predetermined temperature, pressure, and time, and (c) forming a vulcanized belt. Step C of removing from the ring mold and reversing (Example) Hereinafter, the method for manufacturing the belt for power transmission according to the present invention will be described in detail with reference to the accompanying drawings.

In this manufacturing method, the steps include steps A, B, and C. That is, in step A, as shown in Fig. 1, a single material of diene rubber such as NR, SBR%CR, or the like is applied to the outer peripheral surface of a cylindrical drum (d) equipped with a rubber sleeve (S). A compressed rubber sheet of a certain thickness blended appropriately (
An unvulcanized rubber sheet (3) with a thin adhesive rubber sheet (2) attached to 1) is wrapped endlessly around the unvulcanized rubber sheet (3), and a thin adhesive rubber sheet ( 2) Unvulcanized bum sheet (
6) is wrapped to form a wide unvulcanized molded body, which is cut to a certain width, then removed from the drum and cut into an inverted trapezoid shape on both sides using a skiving machine, and the outer peripheral surface is made of cotton, nylon, One or more pieces of rubberized bias cover canvas (7) woven from polyester, aromatic polyamide, or blended yarns thereof are coated with a covering machine to form an unvulcanized belt molded body (8) shown in FIG. 2. form. Note that the unvulcanized rubber sheets (3) and (6) have a thin adhesive rubber sheet (2) attached to the surface, and when wrapping this adhesive pom sheet (2), ) side.

Further, the unvulcanized rubber sheet (6) wrapped around the tensile rope (4) may be the adhesive rubber sheet (2) alone without the stretchable rubber sheet (5), if necessary. Furthermore, the stacking order of each of the above-mentioned constituent materials is reversed, that is, an unvulcanized rubber sheet (6) or an adhesive rubber sheet (2) is placed on the outer circumferential surface of the cylindrical drum (d), and then a tensile rope circumferential surface is coated. The unvulcanized belt molded body (8) formed in the step A is inverted and inserted into a cylindrical ring mold (M) in which a large number of trapezoidal grooves (G) are cut in the width direction.

That is, as shown in the partially enlarged view of FIG.
), and then fit a cylindrical elastic rubber sleeve (11) to its outer circumferential surface, place it in a vulcanizing can, and heat it at a predetermined temperature, pressure, and time. Vulcanize.

At this time, the elastic rubber sleeve (11) pushes the belt bottom (10) toward the back side by the steam pressure during vulcanization, so that the belt completely fills the trapezoidal groove of the mold.

In addition, since the unvulcanized belt molded body is inverted and inserted into the ring mold, even if the tensile rope (4) tries to contract, the mold maintains the tensile rope position through the cover cloth (7). Therefore, even if a flexible rubber is used for the compressed rubber layer (1), the rope will not collapse.

In the next step C, the vulcanized belt is removed from the link mold, turned over again, and the belt bottom (10
) is formed with a wrap belt (12) having an arch shape that bulges on the back side.

Here, by adding an arch to the bottom of the trapezoidal groove (G) of the ring mold (M) that bulges toward the center of the mold, arches are formed on both the back surface (9) and bottom surface (10) of the vulcanized belt. ■You can get a belt with a shape.

(Fig. 6) (Effects of the invention) As described above, the method for manufacturing the power transmission belt of the present invention is to vulcanize a wrap-type belt using a tensile rope with high shrinkage stress in a ring mold. At the time of vulcanization, the unvulcanized belt molded body is set with the back side inside and vulcanized, so there is almost no heat shrinkage during vulcanization of the tensile rope.
In addition, even if a compressed rubber layer having the flexibility necessary for forming the belt cross section is used, it is possible to prevent the tensile rope from sinking into the compressed rubber layer. This makes it possible to obtain a belt with a uniform rope arrangement, high shrinkage stress, that is, a belt with small elongation during running, and a belt with a good external shape.

In addition, the arched shape of the belt bottom formed during vulcanization delays the deformation into the reverse arched shape that tends to occur when conventional belts run, and in addition to maintaining tension due to high shrinkage stress, it also prevents the pulley from bending due to the belt's curved deformation. This manufacturing method has the effect of delaying the decrease in tension due to depression, and is highly expected to be useful as an industrial method in the future.

[Brief explanation of the drawing]

Fig. 1 is a partial perspective view of a power belt molded product for manufacturing a power transmission belt according to the present invention, Fig. 3 is a partially cut-away side view of a ring mold used in the vulcanization mode of the same method, and Fig. 4
5 is a partial perspective view of a vulcanized belt manufactured according to FIG. 4, and FIG. 6 is a cross-sectional view of a vulcanized belt showing another embodiment. 7 are partially enlarged sectional views showing a conventional ring mold vulcanization mode. (1) Compressed rubber layer (2) Adhesive rubber layer (3) Unvulcanized rubber sheet (4) Tensile rope (5) Stretch rubber layer (6 )...Unvulcanized rubber sheet (7)...Cover canvas (8)...Unvulcanized belt molded body (9)...Belt back part (10)...Belt bottom part (11) ...Bum sleeve (12) (12) '...Vulcanized belt patent applicant
Mitsuboshi Belting Co., Ltd. Figure 5 Figure 31 ・16 Figure 7 Figure 1 is Figure 3 Figure 2

Claims (1)

[Claims] 1. A method for manufacturing a V-belt for power transmission, which comprises sequentially carrying out the following steps A, B, and C. (b) An unvulcanized rubber sheet, a tensile rope, and an unvulcanized rubber sheet are sequentially laminated and pasted on the outer peripheral surface of a cylindrical drum to form a wide cylindrical unvulcanized body, and the circumferential direction After cutting it to a certain width, remove it from the drum, skive both sides of the unvulcanized molded product into an inverted trapezoid shape at a predetermined angle, and cover it with a bias cover canvas with rubber to form an unvulcanized belt molded product. Step A: (b) An unvulcanized belt molded body was inserted with the back side of the belt turned inward along the concave groove of a cylindrical ring mold in which a large number of trapezoidal grooves were carved at a constant pitch in the width direction of the outer circumferential surface. After that, a step B of fitting a cylindrical rubber sleeve around the unvulcanized belt and vulcanizing it at a predetermined temperature, pressure, and time; and (c) a step C of removing the vulcanized belt from the ring mold and inverting it.