JPH0239659B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a low edge V-belt and a method for manufacturing the same. (Prior Art) V-belts are divided into two types: wrapped-type V-belts whose outer sides are covered with canvas, and low-edge-type V-belts without canvas on the sides (hereinafter simply referred to as low-edge V-belts). The above-mentioned low edge V-belt is as shown in Fig. 8.
A bottom canvas layer b forming the inner surface of the belt and a bottom rubber layer c
, a tensile band layer d, and a back canvas layer e are laminated in this order, and the tensile band layer d is formed by embedding a core cord f having tensile strength in an adhesive rubber layer g.
The canvas layers b and e that form the inner and outer circumferential surfaces of this low-edge V-belt a are made of rubberized canvas wound into rolls, and the starting edge h that appears on the belt inner and outer circumferential surfaces is Cut at right angles to the direction. Furthermore, as shown in FIG. 9, a low edge V-belt k is also known in which the starting edge of a rubberized canvas is cut into a biased edge to form a biased edge j. (Problem to be Solved by the Invention) Generally, when a V-belt runs, the inner circumferential side of the V-belt becomes a compressed part and the outer circumferential side becomes an elongated part.
In particular, the compression section is subjected to repeated tension and compression stress as the V-belt runs. Therefore, in the case of the low edge V-belt a shown in FIG. 8 above, the stress acts perpendicularly to the canvas starting edge h on the inner circumferential surface, so there is a risk of peeling or cracking of the starting edge h. . On the other hand, the low edge V-belt k shown in FIG. 9 has a bias edge j to make the edge length as long as possible, thereby dispersing the stress. , a sufficient effect cannot be expected, and when a bending force is applied to the belt, stress is concentrated at one point on the side edge of the bias edge j, which tends to cause the canvas to peel off. The workability of manufacturing is poorer than that of conventional methods, and there is a large amount of material loss. That is, the first object of the present invention is to provide a low-edge V-belt with excellent durability by dispersing the stress acting on the starting edge of the canvas constituting the bottom canvas layer. The object of the present invention is to provide a method for manufacturing the above-mentioned low edge V-belt. (Means for Solving the Problems) The present invention solves the above problems by making the starting edge of the canvas into a wave shape that goes in and out in the circumferential direction of the belt. That is, the low edge V-belt according to the first invention includes a bottom canvas layer formed by laminating rubberized canvas rolled into a roll, and short fibers arranged in the width direction of the belt and uniformly dispersed therein. A bottom rubber layer made of rubber, a tensile band layer made of a core cord extending in the circumferential direction of the belt embedded in the rubber, and a back canvas layer made of rubberized canvas are laminated in this order, It is characterized in that the starting edge appearing on the inner circumferential surface of the belt of the rolled canvas constituting the bottom canvas layer is formed in a wave shape. A method for manufacturing a low-edge V-belt according to the second invention includes polymerizing and connecting the side edges of unit bias cloth pieces obtained by cutting rubberized canvas into bias shapes, sequentially performing this process to form a bias canvas, and then The starting edge of the bias canvas is cut into a wave shape, the bias canvas is wound around the outer periphery of the forming drum a required number of times to form a bottom canvas layer, and the short fibers are uniformly distributed on the bottom canvas layer while being arranged in the width direction. The rubber band formed by the rubber band is wound a required number of times to form a bottom rubber layer, and the adhesive rubber band, the core cord, and the adhesive rubber band are sequentially wound on the bottom rubber layer to form a tensile band layer, and further on top of that. A cylindrical belt material is formed on the forming drum by wrapping a bias canvas, then the belt material is vulcanized, the vulcanized belt material is cut into belts having a V-shaped cross section, and the bottom canvas layer is It is characterized in that the waveform starting edge of the bias canvas forming the belt appears on the inner circumferential surface of the belt. (Function) In the above-mentioned low edge V-belt, the starting edge appearing on the inner peripheral surface of the belt of the rolled canvas constituting the bottom canvas layer is made into a wave shape, so that the length of this starting edge is straight in the width direction of the conventional belt. It is longer than a belt that extends in a shape, and the repeated stress of tension and compression that acts on the starting edge as the belt runs is dispersed. In addition, when bending force is applied to the starting edge, stress is concentrated on a line that crosses the belt in the width direction, but since this starting edge is formed in a waveform, stress concentration occurs at multiple locations. It will be dispersed. In addition, in the method for manufacturing the low edge V belt described above, when the canvas is wound around the forming drum, the starting edge is wavy but extends in the belt width direction as a whole, so compared to the conventional bias edge j. This improves workability and also reduces material loss when forming the starting edge compared to the conventional bias edge j. (Effect of the invention) Therefore, according to the first invention (low edge V belt), by making the starting edge appearing on the inner circumferential surface of the belt of the rolled canvas that constitutes the bottom canvas layer wave-shaped, the starting edge The stress acting on the belt is dispersed, and therefore, it is possible to prevent early breakage due to crack generation and decrease in belt life due to peeling of the bottom canvas, thereby extending belt life and eliminating variations in belt life. Further, according to the second invention (method for manufacturing a low edge V belt), while reducing material loss and improving workability compared to the conventional bias edge j,
A low edge V-belt having the canvas layer with the above-mentioned corrugated starting edge can be manufactured. (Example) Examples of the present invention will be described below based on the drawings. As shown in FIGS. 1 and 2, the low edge V-belt 1 has a bottom canvas layer 2 forming the inner peripheral surface of the belt.
A bottom rubber layer 3, a tensile band layer 4, and a back canvas layer 5 forming the outer peripheral surface of the belt are laminated in this order. The bottom rubber layer 3 is made by uniformly dispersing short fibers arranged in the belt width direction in a synthetic rubber such as chloroprene rubber to provide rigidity against compression in the belt width direction and sufficient stiffness in the belt circumferential direction. It provides flexibility. The tensile band layer 4 includes a core cord 6 extending in the circumferential direction of the belt and made of polyester cord, aromatic polyamide fiber with high tensile strength (trade name: Kevlar), glass fiber, etc.
It is comprised of an adhesive rubber layer 7 in which the core cord 6 is embedded. The bottom canvas layer 2 is made of rubberized canvas rolled up and laminated, and the starting edge 8 of the rubberized canvas appearing on the inner peripheral surface of the belt 1 is formed in a wave shape that goes in and out in the circumferential direction of the belt. ing. Further, the back canvas layer 5 is also made of rubberized canvas rolled into a roll and laminated, and the terminal edge 9 of the rubberized canvas appearing on the outer peripheral surface of the belt is similar to the starting edge 8 of the bottom canvas layer 2. It is formed into a wave shape. The waveforms of the starting edge 8 and the ending edge 9 may be a triangular wave as shown in FIG. 5a, a sine wave as shown in FIG. 5b, or a random wave as shown in FIG. However, the waveform is not limited to this, and may have an appropriate wave shape such as a sawtooth shape. Next, a method for manufacturing the above-mentioned low edge V-belt 1 will be explained based on the process diagram shown in FIG. Canvas material A is a plain weave canvas made of cotton, nylon, or a blend of polyester and cotton, either as is or after being subjected to an adhesive treatment such as RFL, chloroprene rubber is rubbed on one side using a known calender to create a friction surface. The canvas member A is cut at a bias angle of 45 degrees to form a unit bias cloth piece B of the required length, and the side edges 11 of the unit bias cloth piece B are cut at a bias angle of 45 degrees. are slightly overlapped and joined to form a bias joint 12, forming a long bias canvas C (FIG. 3C). Next, the tip edge 8a of the bias canvas C is cut into a waveform at right angles to the length direction as shown in FIG.
Next, the bias canvas C is molded into a forming drum 1 of a required diameter.
5, the bottom canvas layer 2 is formed by wrapping the canvas side edges as the front side around which the top surface is wrapped a required number of times, and cutting the terminal edge into a waveform or a straight line. However, in this case, in order to avoid cutting loss of the canvas, it is preferable to cut the canvas in a waveform like the tip edge 8a at the beginning of winding. As is well known, a rubber band 16 having uniformly dispersed short fibers in rubber and having rigidity in the width direction and flexibility in the length direction is wrapped several times around the outer peripheral surface of the bottom canvas layer 2. A thick bottom rubber layer 3 is formed (see FIG. 4), one layer of adhesive rubber band 17 is wound on the bottom rubber layer 3, and the core cord 6 is wound spirally on top of the adhesive rubber band 17. A layer of adhesive rubber band 18 is wound on top, and the core cord 6 is sandwiched between the upper and lower adhesive rubber bands 17 and 18 to form the tensile band layer 4. Next, the bias canvas C is wound a necessary number of times thereon to form the back canvas layer 5. As a result, a cylindrical belt material 20 is formed on the forming drum 10. It is preferable for the back canvas layer 5 to be cut into a wave shape by cutting the starting edge of the bias canvas C into a wave shape, similar to the bottom canvas layer 2, and into a wave shape, similarly to the end edge 9a. Next, the belt material 20 is vulcanized by a known method, cold set after vulcanization, and the belt material 20 is transferred to the forming drum 15.
The belt material 20 is cut into belts having a V-shaped cross section by a known method to obtain the desired low edge V-belt 1.
The leading edge 8a of the bias canvas C forming the back canvas layer 5 appears on the inner circumferential surface of the formed low edge V-belt 1 as a wavy starting edge 8, and the trailing edge 9a of the bias canvas C forming the back canvas layer 5 also forms the low edge V-belt 1. A wavy terminal edge 9 appears on the outer peripheral surface of the V-belt 1. Next, FIG. 6 shows the procedures for a comparison test between the low edge V-belt 1 manufactured by the above method and the conventional low edge V-belt shown in FIGS. 8 and 9.
That is, the driving pulley 22 and the driven pulley 23 were made to have the same diameter (φ55), a tensile load w of 50 kg was applied to the driven pulley 23, and the test was conducted at 4900 rpm. The dimensions of the low edge V-belt used in the test were as shown in Fig. 7: height H = 7.5 mm, width D = 10.5 mm, angle E = 35°, total belt length 36 inches, and the starting edge 8 of the product of the present invention was The triangular wave shown in Figure 5a is used, and the height of the mountain is 2.
mm, pitch 3mm. (The same applies to the terminal edge 9.) The results are shown in the following table.

[Table] However, the test results are the average value of 5 tests. That is, in the case where the starting edge h shown in FIG. 8 was set perpendicular to the longitudinal direction of the belt, cracks occurred in the starting edge h after 230 hours. The durability is as shown in the table, and it was found that the low edge V-belt according to the present invention was significantly superior to conventional products.

[Brief explanation of drawings]

Figures 1 to 7 show embodiments of the present invention; Figure 1 is a perspective view of a low-edge V-belt viewed from the outer peripheral side, and Figure 2 is a perspective view of the low-edge V-belt viewed from the inner peripheral side. Fig. 3 is a manufacturing process diagram of a low edge V belt, and Fig. 4 is a - in Fig. 3 f.
A sectional view, FIG. 5 is an explanatory diagram showing an example of a wave shape,
Figure 6 is an explanatory diagram of the test procedure, Figure 7 is a cross-sectional view of the low edge V-belt used in the test, Figures 8 and 9
The figures are perspective views showing a first example and a second example of a conventional low edge V-belt, respectively. 1... Low edge V belt, 2... Bottom canvas layer,
3... Bottom rubber layer, 4... Tensile band layer, 5... Back canvas layer, 6... Core cord, 8... Starting edge, 8a...
Starting edge, 15...forming drum, 16...rubber band,
17, 18...adhesive rubber band, 20...belt material, B...unit bias cloth piece, C...bias canvas.

Claims (1)

[Claims] 1. A bottom canvas layer formed by laminating rubberized canvas rolled into a roll, and a bottom rubber layer formed by uniformly dispersing short fibers arranged in the belt width direction. , a tensile band layer in which a core cord extending in the circumferential direction of the belt is embedded in rubber, and a back canvas layer made of rubberized canvas are laminated in this order, and the bottom canvas layer is composed of A low edge V-belt characterized in that a starting edge appearing on the inner peripheral surface of the belt of a rolled canvas is formed in a wave shape. 2. The side edges of unit bias cloth pieces cut into bias shapes from rubberized canvas are overlapped and connected, and this is performed sequentially to form a bias canvas.Then, the starting edge of the bias canvas is cut into a wave shape, and the bias fabric pieces are cut into a wave shape. A bias canvas is wrapped around the outer periphery of a forming drum a required number of times to form a bottom canvas layer, and a rubber band made of short fibers arranged in the width direction and uniformly dispersed is wrapped around the bottom canvas layer a required number of times to form a bottom rubber. A layer is formed, and an adhesive rubber band, a core cord, and an adhesive rubber band are sequentially wound on the bottom rubber layer to form a tensile band layer, and a bias canvas is further wound on the bottom rubber layer to form a cylindrical shape on the forming drum. The belt material is then vulcanized, and the vulcanized belt material is cut into belts having a V-shaped cross section, such that the waveform starting edge of the bias canvas constituting the bottom canvas layer is aligned with the inner periphery of the belt. A method for manufacturing a low edge V-belt, characterized in that it is made to appear on a surface.