JP2532954B2 - Endless belt with double teeth and method of manufacturing the same - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed endless belt provided in, for example, an automobile engine and a manufacturing method thereof, and more particularly to an endless belt having teeth formed on both sides and a manufacturing method thereof. .

[Conventional technology]

The toothed endless belt is used in various fields because of its high power transmission ability between pulleys, and usually has teeth only on the inner side. However, in recent years, in order to drive many devices in automobiles or general industrial machines,
Two-toothed endless belts having teeth not only on the inner side but also on the outer side, that is, the back side, have been used.

This double toothed endless belt has an inner endless body consisting of an inner belt tooth and a tooth bottom portion, and an outer endless body consisting of an outer belt tooth and a tooth bottom portion. Each canvas is covered.

In the conventional endless belt with two teeth, a belt-shaped canvas is sewn at both ends to form an endless canvas, which is adhered to the inner endless body and the outer endless body, respectively, or is adhered to the outer endless body surface. As for the canvas, the belt-shaped canvas is glued to the outer endless body in a state where the both ends are simply joined without sewing.

[Problems to be Solved by the Invention]

However, in such an endless belt with toothed teeth, which is formed by sewing the both ends of the belt-shaped canvas or simply matching them,
When the sewn or mating part of the canvas is located on the bottom of the tooth where the rubber layer is thin, the deterioration of the sewn part or mating part easily causes water to easily penetrate into the belt from the sewn part or mating part. There is a problem that the durability of the

The present invention has been made to solve such a problem, and provides an endless belt with toothed teeth having improved durability, and an endless belt with toothed teeth easily manufactured as described above. It is intended to provide a manufacturing method that can be performed.

[Means for solving the problem]

In order to solve the above problems, a first aspect of the present invention is to provide a core wire formed on an inner peripheral surface and an outer peripheral surface of an endless belt with inner belt teeth and outer belt teeth, respectively, and extending along a length direction. A two-toothed endless belt having a toothed endless belt in which at least the inner belt tooth is formed using the outer periphery of a cylindrical mold, wherein the inner and outer peripheral surfaces of the endless belt are It is characterized in that each is covered with a hollow weave canvas, and the peripheral length L of the hollow weave canvas on the outer peripheral surface is determined by the following equation.

L = 2π {(R + PLD value × 2) ² + S × T / π} ^1/2 where R: radius of cylindrical mold S: area per tooth of outer belt tooth T: outer belt tooth Number of teeth PLD value: distance between the center of the core wire and the bottom of the tooth Further, the second invention is a step of covering the cylindrical mold having the tooth profile on the outer peripheral surface with the first stretchable canvas cloth having elasticity in the circumferential direction. And a step of winding a core wire around the outer periphery of the first hollow weave fabric and winding a rubber layer to form a cylinder, and heating and pressing the rubber layer for a short time to partially vulcanize the rubber layer. The step of pressing, the step of releasing the cylindrical body from the cylindrical mold, and the step of covering the outer periphery of the released cylindrical body with the canvas of the second hollow weave, the canvas of the first hollow weave, the core wire, the rubber layer And a step of pressing the cylindrical body made of the second hollow weave fabric to vulcanize the rubber layer to form the belt teeth. To have.

〔Example〕

 The present invention will be described below with reference to illustrated embodiments.

FIG. 2 shows an endless belt 10 with two teeth. This belt 10
Is endlessly formed, and the inner belt teeth 11 and the outer belt teeth 21 are provided at a uniform pitch over the entire circumference. Further, the shape and pitch of the inner belt tooth 11 and the outer belt tooth 21 are the same as each other.

FIG. 1 is an enlarged view of a cross section of the endless belt 10 with two teeth. The toothed endless belt 10 has an inner endless body 13 including a belt tooth 11 and a tooth bottom portion 12, an outer endless body 23 including a belt tooth 21 and a tooth bottom portion 22, and these endless bodies 13,
And a core wire 31 provided between the two. Cord 31 is a belt
It extends along the length direction of 10, ie, the circumferential direction. The inner belt tooth 11 and the outer belt tooth 21 are provided at the same position,
That is, the inner bottom 12 and the outer bottom 22 are formed at the same position. The surface of the inner endless body 13 is covered with a seamless woven canvas 14 and the surface of the outer endless body 23 is covered with a seamless woven canvas 24.

Next, a manufacturing method and a manufacturing apparatus of the endless belt 10 with both teeth will be described.

FIG. 3 shows a first hollow weave canvas 14 coated on the surface of the inner endless body 13. This hollow weave canvas 14 is a cloth having elasticity in the circumferential direction of the belt and is formed into a seamless endless shape. As can be seen, the printed letters 16 such as the manufacturer's name and production lot number are located inside the woven canvas 14.

The material of the hollow weave fabric 14 is nylon, for example, nylon 6
Alternatively, any synthetic fiber made of nylon 66, which has excellent heat resistance and strength, such as polyester, may be used. As for the weaving of the bag-woven canvas 14, a plain weave, a satin weave, a twill weave, or a modified weave of these may be used.

The endlessly shaped hollow weave canvas 14 is put on a cylindrical mold 40 as shown in FIG. This cylindrical mold 40
Has a large number of tooth-shaped grooves 41 extending in the axial direction and formed at equal intervals on the outer peripheral surface thereof.
Corresponds to the belt tooth.

FIG. 5 is an enlarged view showing a state in which the hollow weave cloth 14 is covered with the cylindrical mold 40. As can be seen from this figure, the hollow weave canvas 14 has a diameter substantially the same as that of the cylindrical mold 40, and is in contact with the tip end surface of the raised portion 42 formed between the grooves 41.

Then, as shown in FIG. 6, the core wire 31 is wound around the outer peripheral surface of the canvas 14 of the hollow weave.

As is well known, the core wire 31 is composed of a pair of core wires obtained by twisting in mutually opposite directions (so-called S twist and Z twist). Further, the core wire 31 is molded from glass fiber in this embodiment, but is not limited to this, and may be synthetic fiber such as aramid fiber, or metal fiber such as aluminum or carbon fiber.

When the core wire 31 is wound around the entire outer peripheral surface of the cylindrical mold 40, then, as shown in FIG. 7, the rubber layer 52 is wound around the outer peripheral side of the core wire 31. The rubber layer 52 is the inner belt tooth
11 and the outer belt teeth 21 (FIG. 1) are formed and have a sufficient thickness to fill between the core wires 31. That is, the rubber layer 52 includes the belt teeth 11 of the inner endless body 13 and the outer endless body.
23 belt teeth 21.

As the material of the rubber layer 52, a rubber having a high modulus is desirable because it is necessary to give rigidity to the tooth profile for the belt transmission. Examples of such rubber include chloroprene rubber, ethylene propylene rubber, chlorohydrin rubber, and the like, and hydrogenated nitrile rubber is preferable as the rubber that can withstand severe use.

The cylindrical mold 40, around which the rubber layer 52 is wound, is housed in the vulcanization can 44 as shown in FIG. 8 and preliminarily molded. In this preliminary molding, heating and pressurization are performed in the vulcanization can 44, but the processing time is shorter than that in the normal vulcanization process, and only a partial vulcanization is possible. As a result of this preliminary molding, a part of the rubber layer 52 flows from the gap of the core wire 31 into the groove 41 of the cylindrical mold 40, whereby the canvas cloth 14 of the hollow weave is also formed into a shape along the groove 41. At the same time, it is bonded to the rubber layer, and the inner belt teeth are almost formed. Further, the outer peripheral surface of the rubber layer 52 is also partially vulcanized, and thus the friction coefficient of the outer peripheral surface of the rubber layer 52 is reduced.

FIG. 9 shows the belt teeth 11 formed in the preforming step shown in FIG. By the preforming step, the hollow canvas 14 is adhered to the surfaces of the belt teeth 11.

After the preforming step, the cylindrical mold 40 is taken out from the vulcanizing can 44, and the cylindrical body 17 composed of the first hollow weave canvas 14, the core wire 31 and the rubber layer 52 has a cylindrical shape as shown in FIG. The mold 40 is demolded. Then, the outer periphery of the cylindrical body 17 is covered with the second canvas cloth 24. This second canvas 24 is formed into a seamless endless shape similar to the first hollow weave cloth 14,
It has elasticity in the circumferential direction. The second hollow weave fabric 24 may be made of the same material as the first double weave fabric 14.

The perimeter L of the second canvas 24 is determined according to the following equation (1).

L = 2π {(R + PLD value × 2) ² + S × T / π} ^1/2 ...
(1) where R is the radius of the cylindrical mold 40 S is the area per tooth of the outer belt tooth 21 (area between the belt land line and the tip of the tooth) T is the number of teeth of the outer belt tooth 21 is there.

In the case of the present embodiment, the PLD value is the distance between the center of the core wire 31 and the tooth roots 12 and 22, as shown in FIG.

The circumference L of the second hollow weave canvas 24 is substantially equal to the circumference of the rubber layer 52. Conventionally, when the outer peripheral surface of the rubber layer 52 is not vulcanized, it is very difficult to cover the outer peripheral surface of the rubber layer 52 with a canvas cloth 24 having a peripheral length L because the frictional resistance of the outer peripheral surface of the rubber layer 52 is very large. It was very difficult. On the other hand, in the present embodiment, since the rubber layer 52 is partially vulcanized as described above, the frictional resistance of the rubber layer 52 is significantly reduced. It is possible to easily cover the outer periphery of the rubber layer 52.

Further, the following problems can be prevented by making the circumferential length L of the second hollow weave canvas 24 equal to the length obtained by the equation (1), that is, the outer circumferential length of the rubber layer 52. That is, if the circumference of the second hollow weave canvas 24 is too shorter than the circumference of the rubber layer 52, the canvas 24 will be stretched during the subsequent molding of the belt teeth, so that the rubber will be stretched under heat and pressure. When the layer 52 becomes fluid, the rubber will exude from the stretched fabric 24 of the canvas 24. This leached rubber is used when meshing with the pulley when using the belt.
It causes noise. On the other hand, if the peripheral length of the second hollow weave canvas 24 is longer than the peripheral length of the rubber layer 52, a phenomenon in which the extra canvas 24 is bent or the tooth profile of the belt teeth is generated in the subsequent belt tooth molding. However, there is a problem that it cannot be accurately molded.

The cylindrical body 17 covered with the second hollow weave canvas 24 is attached to, for example, the belt manufacturing apparatus shown in FIG. 11, and is press-bonded to each other and the endless belt 10 is formed with a tooth profile as described below. Becomes

This manufacturing apparatus includes a pair of toothed pulleys 61 and 62 around which the inner endless body 13 is wound, a first press die 71, and a second press die 72. The pair of toothed pulleys 61 and 62 are provided at a predetermined interval, and the belt is configured to be substantially horizontal between the pulleys 61 and 62. The first press die 71 is arranged on the inner peripheral side of the inner endless body 13 and is provided so as to be movable up and down.
A plurality (for example, 15) that engage with the belt teeth of the inner endless body 13
Of the molding groove 73. The second press die 72 is disposed so as to face the first press die 71 and is movable up and down. On the lower surface, a plurality of the same shapes as the first press die 71 (for example, , 15) forming groove 74.

The second press die 72 includes a pair of fixed press die members 75 and 76 provided at both ends, and a molding press die member 77 provided at the central portion. These mold members 75, 76,
Each 77 is configured to move up and down independently. The fixed press die members 75, 76 are opposed to both ends of the first press die 71, and cooperate with the press die 71 to sandwich the rubber layer 52. The molding press die member 77 cooperates with the first press die 71 to form the tooth profile of the belt.

The fixed press die members 75 and 76 are configured to be constantly kept at room temperature, for example, by passing cooling water through a water passage formed inside. On the other hand, the molding press die member 77 is
It has a heating mechanism such as heating steam or an electric heater inside, and its heat capacity is set to be smaller toward the center and larger toward both ends. That is, in the vicinity of the fixed press die members 75 and 76, the molding press die member 77.
Has a large heat capacity, so that the temperature at the contact surface of the molding press die member 77 with the rubber layer 52 becomes uniform throughout.

The first press die 71 is cooled to room temperature by being cooled with cooling water or the like at the portions corresponding to the fixed press die members 75 and 76, and the heat capacity becomes closer to both ends at the portion corresponding to the molding press die member 77. Is heated so that That is, the surface temperature of the portion of the first press die 71 corresponding to the forming press die member 77 is uniform throughout.

Two forming grooves located at both ends of the first press die 71
The distance W1 between the 73 is determined according to the following equation (2). That is, W1 = 2 × π × (r-PLD value) × n / N × (1-c) (2) where, r is the radius of the core wire 31 when the belt is circular, and n is the molding press. The number of belt teeth engaged with the die member 77, N: the number of all belt teeth, c: the coefficient of thermal expansion of the material forming the first press die 71.

Also, the PLD value is the same as the above, as shown in FIG.
It is the distance between the center of 1 and the roots 12 and 22.

On the other hand, the distance W2 between the two molding grooves 74 located at both ends of the second press die 72 is determined according to the following equation (3). That is, W2 = 2 × π × (r + PLD value) × n / N × (1-d) (3) where, d is the thermal expansion coefficient of the material forming the second press die 72.

As can be understood from the equations (2) and (3), when the first and second press dies 71 and 72 are made of the same metal material, c = 2. Therefore, W1 and W2 are PLD values. Differ only by the amount of. That is, the distance W2 between the forming grooves at both ends of the second press die 72 is equal to the distance W1 between the forming grooves at both ends of the first press die 71.
The ratio is W2 / W1 = (r + PLD value) / (r-PLD value).

Next, referring to FIGS. 11 and 12 (a) and (b),
The step of forming the tooth profile will be described.

The cylindrical body 17 covered with the second hollow weave canvas 24 is wound around the pair of toothed pulleys 61 and 62 in advance. First of all
The press die 71 is displaced upward and its tooth groove 73 engages with the teeth of the inner endless body 13. Then, as shown in FIG. 12 (a), the fixed press die members 75 and 76 are lowered to press the rubber layer 52 from above the second hollow weave canvas 24. Here, since the distance W2 between the molding grooves of the second press die 72 is longer than that of the first press die 71, the rubber layer 52 is formed by the engagement of the fixed press die members 75 and 76. The second press dies 71 and 72 are extended by an amount corresponding to the difference in the distance between the molding grooves.

In this state, the molding press die member 77 descends as shown in FIG. 12 (b), and the rubber layer 52 is pressed against the inner endless body 13. Then, the inner endless body 13 and the rubber of the rubber layer 52 are vulcanized by heating and pressing by the first press die 71 and the forming press die member 77 to form the belt teeth. At this time, since the portions pressed by the fixed press die members 75 and 76 are not heated, the rubber is not vulcanized and the belt teeth are not molded.

Next, the rubber layer 52 is moved such that the rightmost belt tooth TR among the belt teeth molded by the molding press die member 77 is located immediately below the left fixed press die member 75. Then, in the same manner as above, the above-mentioned pressing process is repeated to form the belt teeth. During this step, the rubber layer 52 is gradually stretched.

In this way, the outer endless body 23 (FIG. 1) is molded, and its length is longer than that of the inner endless body 13 by the amount corresponding to the PLD value. Therefore, it is possible to obtain a double-toothed belt having an accurate tooth profile over the entire circumference and suppressing residual strain as much as possible. Further, in this embodiment, since the rubber layer formed into a cylindrical body is subjected to press working to form the belt teeth, the manufacturing is easy and the material yield is also good.

Further, as in the conventional case, the inner endless body 13 or the outer endless body 23
In an endless belt with double-teeth teeth whose surface is covered with a canvas having a sewn portion or a mating portion, wear deterioration easily occurs at the sewn portion or the mating portion of the canvas. When it is located at the tooth bottom portion where the wall thickness is thin, there is a problem in that moisture easily enters the inside of the belt from the sewn portion or the joint portion, and this moisture impairs the durability of the belt.

Therefore, in the two-toothed endless belt of this embodiment, since the surfaces of the inner endless body 13 and the outer endless body 23 are covered with a seamless hollow weave fabric, the canvas may be locally deteriorated as in the conventional case. Thus, the durability of the endless belt with both teeth can be improved.

The pressing step for forming the belt teeth on the cylindrical body is not limited to that of this embodiment, and any conventionally known pressing step may be applied.

〔The invention's effect〕

As described above, according to the first aspect of the invention, it is possible to prevent local deterioration of the canvas, and thus improve the durability of the endless belt with teeth.

Further, according to the second invention, the endless belt with double teeth of the first invention can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of an endless belt with double teeth, FIG. 2 is a perspective view showing a schematic configuration of an endless belt with double teeth, and FIG. FIG. 4 is a perspective view showing a process of covering a hollow weave canvas with a cylindrical mold, FIG. 5 is a sectional view showing a state where the hollow weave cloth is covered on the cylindrical mold, and FIG. 6 is a sectional view of the cylindrical mold. FIG. 7 is a perspective view showing a process of winding the core wire, FIG. 7 is a perspective view showing a process of winding a rubber layer on a cylindrical mold, and FIG. 8 is a view showing a cylindrical mold having a rubber layer wound thereon. FIG. 9 is a perspective view showing a state of being housed in a sulfur can, FIG. 9 is a rubber layer after the step of FIG.
And a cross-sectional view showing the core wire, and FIG. 10 shows the cylindrical body taken out from the cylindrical mold and
Fig. 11 is a perspective view showing a step of covering the bag cloth of Fig. 11, Fig. 11 is a sectional view showing an example of an apparatus for carrying out the manufacturing method of the present invention, and Fig. 12 (a) is before the molding press die member is lowered. FIG. 12 (b) is a sectional view showing a state after the molding press die member has been lowered. 11 …… Inner belt tooth 14 …… First woven canvas 21 …… Outer belt tooth 24 …… Second woven canvas 52 …… Rubber layer

Claims (2)

(57) [Claims] 1. An inner peripheral surface and an outer peripheral surface of an endless belt,
Formed by inner and outer belt teeth,
A two-toothed endless belt having a core wire extending along the length direction, wherein at least the inner belt tooth is formed by using the outer circumference of a cylindrical mold, An endless belt with double-toothed teeth, characterized in that the inner peripheral surface and the outer peripheral surface of the belt are respectively covered with a hollow weave canvas, and the circumferential length L of the outer peripheral surface of the hollow weave canvas is determined by the following equation. L = 2π {(R + PLD value × 2) ² + S × T / π} ^1/2 where R: radius of cylindrical mold S: area per tooth of outer belt tooth T: outer belt tooth Number of teeth PLD value: Distance between the center of the core and the root 2. A step of covering a cylindrical metal mold having a tooth profile on an outer peripheral surface thereof with a first stretchable canvas cloth having elasticity in the circumferential direction, and winding a core wire around the outer periphery of the first blanket cloth. Winding the rubber layer to form a cylinder, heating and pressing the rubber layer for a short time to partially vulcanize the rubber layer, and removing the cylinder from the cylindrical mold. A step of releasing, and covering the outer periphery of the released cylindrical body with a second hollow weave canvas, and a cylinder made of the first hollow weave canvas, core wire, rubber layer and second hollow weave canvas And a step of pressing the above to vulcanize the rubber layer to form a belt tooth, thereby manufacturing an endless belt with double-toothed teeth.