JPS6324180B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a wrapped V-belt formed by wrapping a belt core with an outer covering canvas. Conventionally, wrapped V-belts are usually made by cutting a rubberized canvas into a bias shape to obtain a unit bias cloth piece, overlapping the side edges of the unit bias cloth pieces to bring them close together, and repeating this process to create a long length. A bias canvas is used, and the bias canvas is cut in the longitudinal direction to a width suitable for winding around the belt core. The front and rear edges are also overlapped. However, with such a wrapped V-belt,
Because the thickness of the overlapping joints on the side edges of the unit bias cloth piece and the overlapping joints on the front and rear edges of the outer covering canvas increases, stress is concentrated on both of the joints while the belt is running, and other parts Fatigue occurs more quickly and cracks are more likely to occur than belt cores, and positional fluctuations occur on the pulleys, causing vibrations.Furthermore, the position of the core cord (tensile member) in the belt core is Since the pressure is not uniform over the entire length, stress concentration occurs in the cord portion, and there is a problem in that early separation occurs between the core cord and the adhesive rubber. In addition, the polymerization thickness at the polymerization connection portion is 3
Due to the size constraints of ~5 mm, there was some concern that the work required skill. SUMMARY OF THE INVENTION An object of the present invention is to provide a wrapped V-belt that runs smoothly, generates extremely low noise, and has an extended belt life. In order to achieve the above object, the present invention is made by cutting a rubberized canvas material into a bias shape to form a unit bias cloth piece, and sequentially butt and connect the side edges of the unit bias cloth piece by sewing. The outer covering canvas is wound around the outer surface of a belt core body having a substantially V-shaped cross section, and the leading edge and rear end edge of the outer covering canvas are each formed in a wave shape. Embodiments of the present invention will be described in detail below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a wrapped V-belt, in which the outer periphery of a belt core 2 is covered with an outer covering canvas 3. As is well known, the belt core 2 has a substantially V-shaped cross section and is composed of a bottom rubber layer 4 made of cushion rubber, and a tensile layer 5 stacked on top of the bottom rubber layer 4. The tensile material layer 5 has a tensile material cord 6 attached to an adhesive rubber 7.
It is buried inside. On the other hand, the outer covering canvas 3 is formed by cutting a rubberized plain weave canvas into a bias shape to form a unit bias cloth piece 8, and sequentially butts and connects the side edges of the unit bias cloth piece 8 by sewing a belt. It has a width that surrounds the core body 2, and is wound with the required amount of ply in the longitudinal direction of the belt core body 2, and both side edges are slightly overlapped. The front end edge 9, which is the beginning of winding, and the rear end edge 10, which is the end of winding, of the outer covering canvas 3 are each cut into a zigzag wave shape. By cutting into a wave shape in this manner, the substantial length of the leading edge 9 and trailing edge 10 is reduced compared to the conventional cutting straight at approximately right angles to the longitudinal direction of the belt or in a bias shape. As a result, the stress acting per unit length becomes smaller, and the end edges 9, 10
The repeated stress acting on the is dispersed. In addition, since the substantial length of both end edges 9 and 10 is increased, the rubber coated on the outer covering canvas 3 is formed into a straight line by applying pressure and heat during belt vulcanization. In the case of rubber, it flows only in the direction perpendicular to the edge, whereas in the case of a wave shape, it flows in a wide range outside of each wave, and by improving the flow of the rubber in this way, the outer canvas The difference in level between the overlapping connection portions at the leading edge 9 and trailing edge 10 of 3 is reduced, and together with the machine-sewn connection of the unit bias cloth pieces 8, the cross-sectional shape can be made uniform. Note that the leading edge 9 and the trailing edge 10 may be cut into a wavy shape in a direction perpendicular to the longitudinal direction of the outer covering canvas 3, but they may also be cut into a wavy shape in a bias direction with respect to the longitudinal direction. It is preferable to do so. Further, the waveforms of the leading edge 9 and the trailing edge 10 may be triangular waveform, sinusoidal waveform,
Any waveform such as a random waveform may be used, and the waveform is not limited to these shapes. For example, an appropriate waveform such as a sawtooth shape may be used. Furthermore, it is desirable that the leading and trailing edges 9 and 10 are butt-connected. Next, a method for manufacturing the wrapped V-belt 1 will be explained with reference to FIGS. 2a to 2g. First, as the canvas material 11, cotton yarn or a blended yarn made by appropriately blending cotton with thermoplastic resin fibers such as nylon or polyester fibers is added to a plain weave canvas used for warp and warp yarns, and chloroprene rubber or natural Rub kneaded rubber mixed with rubber to form a material with friction surfaces on both sides (see Figure 2a). This canvas material 11 is approximately 45cm long in the longitudinal direction.
A unit bias cloth piece 8 is formed by bias-cutting at an angle of 100 degrees (see FIG. 2b), and then the side edges 8a, 8a of the unit bias cloth pieces 8, 8 are aligned and overlapped, For example, use a 40-count cotton thread to sew with an overlock sewing machine (manufactured by Pegasus) (see Figure 2 c) to create a connection part A that is butt-sewn and connected, and repeat this repeatedly to create the bias canvas 1.
2 (see Figure 2d). Next, the bias canvas 12 is cut in the longitudinal direction to have a width slightly wider than the circumference of the belt core 2, which is separately formed in advance, to form the outer covering canvas 3. Before wrapping the outer covering canvas 3 around the belt core 2, its leading edge 9 is cut into a wave shape in a bias direction forming an angle of approximately 45 degrees with respect to the longitudinal direction or in a direction perpendicular to the longitudinal direction. The procedure for wrapping the outer covering canvas 3 around the belt core 2 is, for example, by stretching the belt core 2 between two pulleys and wrapping the leading edge 9 of the outer covering canvas 3 around the belt core 2.
After fixing it to the belt core 2, while moving the belt core 2, wrap the outer covering canvas 3 along the longitudinal direction of the belt core 2 using a pressure roller or the like, and press both edges of the belt core 2 against the belt core 2 at the same time. This is crimped and wrapped, and both edges of the outer covering canvas 3 are attached to the edge 2a of the belt core 2 on the bottom side (or back side) of the belt core 2.
(See Figure 2g). After wrapping the outer covering canvas 3 around the belt core 2 in required ply, the trailing edge 10 is cut into a wave shape in the bias direction or perpendicular direction to the longitudinal direction and joined, similarly to the leading edge 9. (See Figure 1). In this case, the leading edge 9 and trailing edge 10 of the outer covering canvas 3
It is desirable to butt and join. As is well known, the V-belt material around which the outer covering canvas 3 is wrapped is mounted in a known vulcanization mold in a set of a large number of pieces, and is charged into a vulcanizer and vulcanized.
After cold setting, it is removed from the vulcanization mold.
A desired wrapped V-belt 1 can be obtained. Next, a test will be described in which the belt performance of the B-type 42 standard wrapped V-belt was compared between the inventive type and the conventional type. (i) Crack initiation test As shown in Figure 3, the drive pulley 21 (diameter
70mm, 1800rpm) and driven pulley 22 (diameter 160
A V-belt 23 was wound between the V-belt 23 and the V-belt 23, and a load W ₁ = 15 kg was applied to the V-belt 23 with a pressure pulley 24 (diameter 45 mm), and the time required for a crack to occur at the bottom was measured. . (ii) Vibration generation test and load-slip test As shown in Figure 4, the drive pulley 31 (diameter
100mm, 1800rpm) and driven pulley 32 (diameter 100
The vibration generation rate and low-load slip rate were measured when a V-belt 33 was wound between the belts (mm) and a load W ₂ =20 kg was applied to the driven pulley 33 in the S direction. Here, the vibration occurrence rate is the ratio of the number of vibrations of ±1 mm or more among 100 V-belts tested, and the low-load slip rate is the ratio of the number of V-belts vibrating at least ±1 mm. Refers to the rotation ratio between the pulley 31 and the driven pulley 32. The measurement results of each of the above tests are shown in the following table.

[Table] As is clear from the above results, the type of the present invention is superior to the conventional type in terms of crack generation time, vibration generation rate, and low load slip rate. According to the wrapped V-belt according to the present invention, the side edges of the unit bias cloth pieces are successively butt-sewn and connected to form the outer covering canvas, and the leading edge and the rear end edge of the outer covering canvas are formed into a wave shape. Therefore, the shape and cross-sectional area are almost uniform all around, and
The repetitive bending stress that acts on both edges of the outer canvas is dispersed, which reduces the variation in bending stress that occurs in the belt itself, eliminates uneven rotation, runs smoothly on the pulleys, and significantly reduces noise. At the same time, the crack initiation time is extended and the belt life is extended.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention; FIG. 1 is a partially cut away perspective view of a wrapped V-belt, FIGS. FIG. 3 and FIG. 4 are explanatory views showing the test procedure, respectively. 1... Wrapped V-belt, 2... Belt core,
3... Outer covering canvas, 8... Unit bias cloth piece, 9...
... leading edge, 10... trailing edge, 11... canvas material,
12...Bias canvas.

Claims (1)

[Scope of Claims] 1 A rubberized canvas material is cut into a bias shape to form a unit bias cloth piece, and the side edges of the unit bias cloth pieces are successively butted and sewn together to connect the outer covering canvas, which has a cross section. 1. A wrapped V-belt, which is wound around the outer surface of a substantially V-shaped belt core, and characterized in that the outer canvas has a leading edge and a trailing edge each formed in a wave shape. 2. The wrapped V-belt according to claim 1, wherein the leading edge and the trailing edge of the outer covering canvas have the same wave shape and are butted against each other.