JPH066350B2 - Transmission belt manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a transmission belt of embedded tensile body, which is applied to, for example, a timing belt for a vehicle, and particularly, transmission of a tensile body which is not easily unraveled. The present invention relates to a method for manufacturing a transmission belt that enables manufacturing of the belt.

(Prior Art) Conventionally, as a power transmission belt used for a vehicle timing belt or the like, for example, as shown in FIG. 7, glass fibers, metal fibers, etc. are formed in a belt body 1 made of NBR (nitrile-butadiene rubber) or the like. There is a thread-shaped tension member 2 embedded therein. A canvas 3 is attached to the inner surface of the belt body 1.

When manufacturing such a transmission belt, for example,
As shown in the figure, after the canvas is wound around the drum-shaped mold 4 in which the side plates 4a and 4a are arranged on both sides so as to be freely separated from each other, the tensile body 2 is spirally wound. After that, the sheet material 5 made of NBR or the like is wound around the molding die 4 from the outside of the tensile body 2, and then the tensile body 2 and the sheet material 5 are brought into close contact with each other by heating on the outer peripheral surface portion of the molding die 4 to form a cylinder. The shaped preform is manufactured, and thereafter, the preform is cut along the radial cutting line A in the axial direction to a predetermined width.

(Problems to be Solved by the Invention) In the above-described conventional manufacturing method, the tensile body 2 is densely spirally wound around the molding die 4 at a constant pitch.

Therefore, after the preform is formed, the tensile body 2 in the transmission belt 6 as the final formed product obtained by cutting the preform is
As shown in FIG. 10 and FIG. 10, since the large angle θ is formed with respect to the axis B of the transmission belt 6, the area of the cut surface 2a of the tensile body 2 becomes relatively large.

As a result, on the cut surface of the tensile body 2, as shown in FIG. 10, the number of the frayed portions 2b of the tensile body 2 increases, and there arises a problem that the tensile body 2 frays during use of the belt. There are cases.

As the tensile body 2, a glass fiber is generally used as RF.
An L (resorcin / formalin / latex) treated and twisted product is often used, and this product is retained by the adhesive layer even after cutting as described above, and the occurrence of fraying is relatively small.

However, when a metal wire tensile member is used, the bonding process is often performed in a wire state after twisting, and the bonding process liquid does not sufficiently enter the inside of the wire. Many.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a portion of the tensile body to be cut on the outer peripheral surface of a drum-shaped mold for spirally winding the tensile body. A protrusion is provided at the position, and when winding the tensile body, the tensile body is hooked on the protrusion so that the cut portion of the tensile body is bent in the axial direction of the molding die. ing.

(Operation) According to the method of the present invention, the tensile body is bent in the axial direction at the cutting point, so the surface area at the cut surface becomes small, and the fraying of the fibers constituting the tensile body is reduced accordingly. To do.

Therefore, the tensile body is less likely to fray when the manufactured belt is used.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

The flow of the whole manufacturing process is the same as the conventional method. That is, as shown in FIG. 1, first, the canvas is wound around the drum-shaped mold 10, and then the thread-shaped tensile member 11 is wound in a spiral shape. Next, NB is applied to the molding die 10 from the outside of the tensile body 11.
The sheet material 12 made of R or the like is wound. After that, the tensile body 11 and the sheet material 12 are brought into close contact with each other on the outer peripheral surface of the molding die 10 by heating to manufacture a cylindrical preform.
After that, the preform is axially cut along the radial cutting line A ₁ to manufacture an endless belt-shaped transmission belt having a predetermined width.

In such a method, in the present embodiment, as shown in FIGS. 1 to 5, a molding die 10 provided with a pin 13 at a position to be a cut portion of a preform is used. That is, the molding die 10 is in the shape of a gear having a tooth-shaped concave portion 10a on the outer peripheral surface, and the pins 13 are arranged inside the cutting line A ₁ on both axial sides thereof. These pins 13
Is a piece 15 fixed to both inner peripheral portions of the molding die 10.
It is slidably mounted in the fitting hole 15a provided in the.
The upper end 13a of the pin 13 projects from the outer peripheral surface of the mold 10 through a through hole 10b formed in the mold 10. Further, the lower end 13b of the pin 13 projects from the lower side surface of the piece body 15. The pin 13 has a spring 16
Is pressed downward by. The lower end surface of the pin 13 is a tapered surface corresponding to the tapered surface of the lower side surface of the piece body 15. On both sides in the axial direction of the molding die 10,
The side plates 17, 17 are arranged so as to be movable in and out of the axial direction. These side plates 17, 17 have tapered surfaces 17a corresponding to the tapered surfaces of the bridge body 15 on the inner surface,
17a. Then, by bringing the side plate 17 into contact with the molding die 10, the pin 13 is moved upward against the pressing force of the spring 16 by the guide of the tapered surface 17a of the side plate 17, and the upper end thereof is moved. 13
a projects a predetermined amount outward from the outer peripheral surface of the molding die 10 (state shown in FIG. 4). Further, by separating the side plate 17 from the molding die 10, the pin 13 moves downward due to the pressing force of the spring 16, and the upper end 13a thereof is recessed from the outer peripheral surface of the molding die 10 and the lower end 13b thereof.
Protrudes from the lower surface of the piece 15 by a predetermined size (state of FIG. 5). Then, as shown in FIG. 4, the side plates 17, 17 are in contact with both sides of the mold, that is, the upper end 13a of the pin 13 is projected outward from the outer peripheral surface of the mold 10, A tensile member 11 is attached to the outer peripheral surface of the molding die 10.
Wrap around. In this case, as shown in FIG. 1, the portion other than the cutting portion is spirally wound at a fine pitch, but the tension member 11 is hooked on the pin 13 in the cutting portion in the axial direction of the mold 10. It is bent, and its end is clamped and fixed between the piece 15 and the side plate 17. After that, the sheet material 12 is wound around the outer peripheral surface of the molding die 10, and the tensile body 11 and the sheet material 12 are brought into close contact with each other by heating to produce a cylindrical preform. When the pin 13 is separated from the molding die 10, the pin 13 is moved downward by the pressing force of the spring 16 so that the upper end 13a thereof is recessed from the outer peripheral surface of the molding die 10 as shown in FIG.

According to the transmission belt 14 manufactured by such a method, as shown in FIG. 6, the tension member 11 makes an extremely small angle θ ₁ with respect to the belt axis B ₁ at the belt cutting surface 14a portion, and the resistance thereof is The surface area of the cut surface 11a of the tension body 11 is close to the cross-sectional integral of one tensile body 11 and is extremely smaller than that of the conventional one.

Therefore, when the belt is used, the fibers forming the tensile body 11 are less likely to be frayed, and the tensile body can be prevented from fraying.

The present invention can be applied not only to a so-called plural production in which a plurality of transmission belts are obtained by dividing a preformed product in the axial direction along a cutting line in the radial direction to obtain a plurality of transmission belts.

(Effects of the Invention) As described above, according to the present invention, a protrusion is provided on the outer peripheral surface of the mold around which the tensile body is wound, the protrusion being located at the cut portion of the tensile body. At the time of winding, the tensile body is hooked on the projection and the cut portion of the tensile body is bent in the axial direction of the forming die. Therefore, the transmission belt has a small surface area at the cut surface of the tensile body. Can be manufactured, and the fibers constituting the tensile body are less likely to fray when the belt is used.

[Brief description of drawings]

FIG. 1 is a view showing a manufacturing state for explaining an embodiment of the present invention, FIG. 2 is a radial cross-sectional view of a forming die in FIG. 1, and FIG. 3 is a mutual relation position between the forming die and a side plate. FIG. 4 is an enlarged view of the IV circle portion of FIG. 3, FIG.
FIG. 6 is a view similar to FIG. 4 at the time of releasing the mold, FIG. 6 is an enlarged view showing a part of the transmission belt manufactured by the method of the embodiment, and FIG. 7 is a structural example of the transmission belt. A sectional view, FIG. 8 is a view showing a manufacturing state for explaining a conventional example, FIG. 9 is an enlarged view of a part of a transmission belt manufactured by a conventional method, and FIG. It is a figure which expands and shows a part of figure. 10 ... Mold, 11 ... Tensile body, 12 ... Sheet material, 1
3 ... Protrusion, 14 ... Transmission belt, A ₁ ... Cutting line.

Claims (1)

[Claims] 1. A spiral wound filament-shaped tensile body is wound around a drum-shaped molding die, and a sheet-shaped material is wound around the molding die from the outside of the tensile body. A cylindrical preform is manufactured by closely contacting the tensile body and the sheet-shaped material on the outer peripheral surface, and thereafter the preform is divided in the axial direction along a cutting line in the radial direction to form an endless belt. In the method of manufacturing a transmission belt of embedded tensile body, a protrusion is provided on an outer peripheral surface of a mold around which the tensile body is wound, the protrusion being located at a cut portion of the preform. A method for manufacturing a transmission belt, characterized in that, at the time of winding, the tensile body is hooked on the projection, and a cut portion of the tensile body is bent in an axial direction of the molding die.