JPH0571817B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a toothed belt whose meshing surface is reinforced with a woven fabric, and a method for manufacturing the same. (Prior Art) Toothed belts are used in driving parts of various machines, power transmission parts of automobiles, office equipment, etc. to synchronize the timing between the driving side and the driven side.
These toothed belts have a woven fabric attached along their meshing surfaces for reinforcement. This woven fabric usually uses crimped synthetic fiber yarns as the yarns extending in the longitudinal direction of the belt. By the way, when molding a toothed belt, as shown in FIGS. 5 and ₆ , a woven fabric b, The expanded body c and the unvulcanized rubber d are placed and heated under pressure to form and vulcanize the toothed belt. Therefore, woven fabric b needs to change from a nearly flat state (see Figure 5) to a bent state (see Figure 6), and it is quite easy to stretch, and this stretching can be done with small stress. It has to be something. Further, in the toothed belt, an extension body c is embedded in a spiral shape in the longitudinal direction of the belt in a belt main body having teeth on the surface, and a woven fabric b is attached to the surface.
This woven fabric b consists of warp threads extending in the longitudinal direction of the belt and weft threads extending in the width direction of the belt. The warp threads are crimped synthetic fiber yarns, and the weft threads are normal synthetic fiber threads. Therefore, when this woven fabric b is attached to a toothed belt, the crimped threads are sufficiently elongated on the top surfaces of the teeth, but are not sufficiently elongated on the bottom and dedendum surfaces of the teeth. It will be installed in the same condition. As an example, when calculating the elongation rate of the toothed fabric from an existing toothed belt, the elongation rate is 70 to 75% on the top surface of the tooth of the toothed belt, and 30 to 35% on the bottom surface of the tooth.
%, and is worn with the dentinal surface elongated by about 45 to 50%. In this way, in order to improve the abrasion resistance and flexibility of the toothed woven fabric of a toothed belt, the crimped yarn is not sufficiently stretched at least on the root surface, root surface, and tooth surface of the tooth of the toothed belt. Toothed belts are manufactured by press-fitting toothed woven fabrics having crimped synthetic fibers so that they can be worn in the same condition (for example, Japanese Utility Model Application No. 57-190943, Japanese Utility Model Application No. 190943, No. (Refer to Publication No. 190944 and Japanese Utility Model Application Publication No. 1983-77836). (Problems to be Solved by the Invention) In the above-mentioned technique, a certain amount of elongation remains in the toothed woven fabric after vulcanization, but since the molding is performed using press-fitting, the quality varies. That is, no measures have been taken to prevent the crimped thread from being sufficiently stretched on the tooth bottom surface or the like. The present invention has been made in view of these points, and provides a toothed belt in which the wear resistance and flexibility of the toothed woven fabric are improved, as well as a toothed belt that can be manufactured without variation in quality. The object of the present invention is to provide a method for manufacturing a belt. (Means for Solving the Problems) The invention of claim 1 provides a toothed belt in which the belt meshing surface is reinforced with a woven fabric, wherein the warp extending in the longitudinal direction of the belt of the woven fabric is a crimped yarn of synthetic fiber. ,
When the above woven fabric has a weft density of 1 on the tooth tip surface,
It is characterized in that the weft thread density on the tooth root surface is 1.5 to 3.0, and the weft thread density on the dedendum surface is 1.5 to 2.5. In other words, the elongation of the toothed fabric that reinforces the belt meshing surface remains not only on the tooth root surface but also on the tooth root surface, and remains locally on the tooth root surface and tooth root surface. According to the second aspect of the invention, the coefficient of friction of the toothed belt molding die is locally changed in order to allow the elongation of the toothed woven fabric to remain locally. Specifically, in a method for manufacturing a toothed belt in which the belt meshing surface is reinforced with a woven fabric, a tooth bottom surface mold part for molding the belt tooth root surface of a toothed belt molding mold and a tooth mold part for molding the belt tooth root surface are used. The coefficient of friction of the main mold part is made 0.3 to 0.5 higher than other parts, and the woven fabric, tensile material, and unvulcanized rubber are placed on top of it in this order, and heated and pressed to produce a toothed belt. It is characterized by In the third aspect of the invention, an adhesive is locally applied to the toothed belt molding die in order to locally retain the elongation of the woven fabric. Specifically, in a method for manufacturing a toothed belt in which the belt meshing surface is reinforced with a woven fabric, a tooth bottom surface mold part for molding the belt tooth root surface of a toothed belt molding mold and a tooth mold part for molding the belt tooth root surface are used. The method is characterized in that the main mold part is coated with an adhesive in advance, a woven fabric, a tensile material, and an unvulcanized rubber are placed on top of the adhesive in this order, and heated and pressed to produce a toothed belt. (Function) According to the invention of claim 1, when the woven fabric reinforcing the belt meshing surface has a weft density of 1 on the tooth tip surface,
Since the weft density of the tooth bottom surface is 1.5 to 3.0, the woven fabric is not stretched on the tooth bottom surface, and even if a large stress is applied to the woven fabric, the stress applied to the tooth bottom surface is extremely small. Therefore, damage does not progress rapidly during use, and use can be continued until the woven fabric is completely worn out. In addition, not only the root surface of the tooth but also the root surface, which is likely to be the starting point for cracks, is crimped with a weft density of 1.5 to 2.5, so it is difficult to weave when external force is applied locally to the tooth. The cloth follows the deformation of the teeth. According to the occurrence of claim 2, in the toothed belt molding die, the friction coefficient of the tooth root surface mold part for molding the belt tooth root surface and the tooth root surface mold part for molding the belt tooth bottom surface is different from each other. Since the woven fabric is larger than the portion , it becomes difficult for the woven fabric to slip during molding and vulcanization of the belt, that is, during press-fitting, and the residual elongation of the woven fabric in that portion becomes large. According to the invention of claim 3, in the toothed belt molding die, an adhesive is applied to the tooth root surface mold portion for molding the belt tooth root surface and the tooth root surface mold portion for molding the belt tooth bottom surface. Since the woven fabric is fixed to the mold during molding and vulcanization, it is difficult for the woven fabric to slip when the belt is molded and vulcanized, that is, when it is press-fitted, and the remaining elongation of the woven fabric in that area is increased. (Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In Fig. 1 showing the overall structure of the toothed belt,
1 is a toothed belt, and an upper rubber layer 4 is placed above a core layer 3 in which a core cord 2 is embedded in a spiral shape.
are laminated, a tooth rubber layer 5 is laminated on the lower side, and a woven fabric 6 is attached to the lower tooth surface. In FIG. 2 showing an enlarged view of the tooth portion 7 of the tooth rubber layer 5, 8 is the tip surface which is the tip surface of the tooth portion 7;
is a tooth surface that is continuous with the tooth top surface 8 and constitutes the side surface of the tooth portion 7; 10 is a tooth bottom surface located between the tooth portions 7; and 11 is a tooth surface between the tooth surface 9 and the tooth bottom surface 10. This is the dentinal surface where it is located. In the woven fabric 6, the warp extending in the longitudinal direction of the belt is a crimped synthetic fiber, and when the weft density of the tooth tip surface 8 is 1, the weft thread density of the tooth root surface 11 is 1.5 to 1.
2.5, and the tooth bottom surface 10 has a weft density of 1.5 to 3.0. However, woven fabric 6
is installed in a state where it is not stretched to its stretching limit, and the woven fabric 6 on the tooth root surface 10 and the tooth root surface 11 is thick and can sufficiently withstand wear. Moreover, the woven fabric 6 is not stretched on this tooth root surface 10, and therefore the stress applied to the tooth root surface 10 is extremely small. Therefore, with conventional belts, if a large stress is applied to the woven fabric at the bottom surface of the tooth during use, that force will act in a direction that causes the woven fabric to peel off from the belt body, causing wear over long periods of use. As the progress progresses, the woven fabric peels off from the belt main body, and the damage progresses rapidly. However, in this embodiment, the woven fabric on the tooth root surface 10 and the tooth root surface 11 is thick, so that damage does not progress rapidly. It can be used continuously until the woven fabric 6 is completely worn out. Furthermore, since the crimped yarn is mechanically bonded to the rubber, it has the effect of increasing adhesive strength. Note that the degree of wear on the tooth tip surface 8 is small, and the pressure applied to the woven fabric 6 acts in the direction of pressing it against the belt body, so the crimped yarn is installed in a fully stretched state. There is no problem. The tooth root surface 11 between the tooth surface 9 and the tooth bottom surface 10 is likely to become a starting point for cracks, and when a local external force is applied to the tooth portion 7, the woven fabric 6 is exposed to the tooth portion 7 (tooth rubber). Since a woven fabric 6 with large elongation is required to follow the deformation of
It is installed so that it is in the following condition. in this way,
The woven fabric 6 is attached not only to the tooth root surface 10 but also to the tooth root surface 11 close to the tooth root surface 10 without being stretched to its elongation limit, which reduces the wear-resistant effect of the woven cloth 6 on the tooth root surface 10. This increases the overall resistance to wear. The above-mentioned toothed belt 1 is manufactured basically in the same manner as the conventionally known method, but the toothed belt molding die 12 used for the molding is different. That is, the molding recess 12a of the mold 12 is
As shown in the figure, a belt tooth tip surface mold part 13 for molding the tooth tip surface 8 of the toothed belt 1 and a toothed belt 1
a belt tooth surface mold part 14 for molding the tooth surface 9;
It has a belt tooth root surface mold part 15 for molding the tooth root surface 11 of the toothed belt 1, and a belt tooth root surface mold part 16 for molding the tooth root surface 10 of the toothed belt 1, The coefficient of friction of the mold part 15 for the surface and the mold part 16 for the bottom surface of the belt tooth is compared with that of the other mold parts 13 and 14.
It is increased by about 0.3 to 0.5. This makes it difficult for the woven fabric to slip during molding and vulcanization of the belt, that is, during press-fitting, and increases the remaining elongation of the woven fabric on the tooth root surface and tooth bottom surface of the toothed belt after vulcanization. Specifically, as a method for increasing the coefficient of friction, only the mold parts 15 and 16 of the mold 11 have a worse surface roughness than the other mold parts 13 and 14. Further, the mold parts 15 and 16 are coated with an adhesive, and when press-fitting, the woven fabric 6 comes into contact with the adhesive and is fixed to the mold parts 15 and 16.
By partially suppressing the elongation of the woven fabric 6, the remaining elongation of the woven fabric 6 can be locally increased. Note that this adhesive can be easily peeled off from the mold 11 after the belt is vulcanized. Next, the results of tests conducted regarding local variations in the number of warp yarns of the woven fabric 6 of the toothed belt 1 and variations in running life will be explained. Test belt Inventive example 1 was manufactured using woven fabric A by molding method A, and inventive example 2 was manufactured using woven fabric A and manufacturing method B.
Manufactured using. Comparative Example 1 uses woven fabric A,
Comparative Example 2 was molded using woven fabric B by the conventional method. In addition, the warp of woven fabric A is woolly 6 nylon,
The weft is nylon 6 and has a composition of 210d/1 x 40d/5/110 x 140/5cm, while woven fabric B has wooly 66 in the warp.
The composition is 210d/1 x 70d/4/110 x 135/5cm using nylon and 66 nylon for the weft. Further, the warp density of the woven fabric 6 was such that, when the tooth tip surface 8 was 1, the average tooth surface 9 was 1, the tooth root surface 11 was 2, and the tooth bottom surface 10 was 2. Molding method A is a method in which a material having a high coefficient of friction (for example, urethane resin) is locally baked and coated on the belt tooth root surface mold part 15 and the belt tooth root surface mold part 16, and Method B is
This is a method using a mold part 15 for the belt root surface and a mold part 16 for the belt tooth bottom surface with poor surface roughness. Belt dimensions are belt width 17mm, tooth pitch 8
mm, cord pitch 1.5mm, belt length 40 inches,
A twisted glass fiber cord was used as the tensile material (ECG150 3/13). Test method The running test was conducted using four toothed pulleys 21, 22, 23, and 24 (all of which have teeth), as shown in Figure 4.
24 pieces) and 4 tension pulleys 25, 26,
A test belt 29 was wound around 27 and 28 (diameter 32 mm), and the test belt 29 was run under a tension of 2T=40 Kgf, and the time when the belt broke was defined as the end of its life. Evaluation method Variation in weft density The weft density per constant length was measured along each surface of the tooth tip, tooth surface, tooth root surface, and tooth root surface. The specification of Comparative Example 1 is set as 100, and each side is
Displayed as an index. Note that the variation σ ² and the variation index are determined by the following formula. σ ² = ₂₀ 〓 ^iml (xi−x) ² /20 Here, x = ₂₀ 〓 ^iml xi / 20 Variation index = {(variation of each invention example) /
(Variation in Comparative Example 1)}×100 Variation in running life The time until belt breakage was logarithmically converted, and the variation and variation index were determined based on the values of n=20 belts with each specification. Therefore, as in the case of the variation in weft density, the values of Comparative Example 1 were set as 100 and expressed as an index. Test results are shown in the table below.

[Table] By the way, when the weft density of the tooth tip surface 8 is set as an index of 1, the index of the weft thread density of the tooth root surface 11 is 1.5 to 2.5.
is suitable, and if the weft density index is less than 1.5, cracks will occur from the tooth root surface 11 during running.
enters early and has a short lifespan. On the other hand, if the weft density index is greater than 2.5, there are too many yarns in the warp expansion and contraction part, resulting in poor meshing with the toothed pulley and the tooth surface 9.
The life will be shortened due to uneven wear. The appropriate weft density of the tooth bottom surface 10 is an index of 1.5 to 3.0, and if the index of the weft density is less than 1.5,
Again, the warp threads are in an elongated form and wear causes premature belt breakage. In addition, when the weft density index is 3.0 or more, the fiber content (woven fabric density)
As a result, the belt thickness at the tooth bottom surface 10 becomes unstable, which tends to cause poor meshing during running, causing uneven wear on the tooth surface 9, tooth bottom surface 10, and tooth root surface 11, leading to premature service life. Therefore, according to the above configuration, the coefficient of friction of the mold part 15 for the belt root surface and the mold part 16 for the belt root surface is made approximately 0.3 to 0.5 larger than that of the other mold parts 13 and 14, or An adhesive is applied to the mold parts 15 and 16 of the belt so that the woven fabric becomes difficult to slip during molding and vulcanization of the belt, that is, during press-fitting.
The forming process for increasing the residual elongation of the woven fabric 6 is now performed in an extremely stable manner, and there is little variation in the quality of the manufactured toothed belts 1. In addition, the toothed belt 1 manufactured in this way
Deformation of the tooth portion 7 and peeling of the woven fabric 6 due to the deformation,
This prevents the occurrence of cracks on the tooth flank 11, and even when the toothed belt 1 is used under high load conditions, it prevents wear on the teeth 7, extending the belt life as a whole compared to conventional ones. It is possible to reduce the variation in (Effect of the invention) In the invention of claim 1, when the weft density on the tooth tip surface is 1, the weft thread density on the tooth root surface is crimped and is 1.5 to 2.5, so the woven fabric is thick and It prevents the occurrence of cracks and has sufficient resistance to wear, and the weft density on the tooth root surface is in a crimp state of 1.5 to 3.0, so the stress applied to the tooth root surface is extremely small, and damage will not occur rapidly during use. There is no progress to the process, and the fabric can be used continuously until it is completely worn out.
Belt life is extended. In the invention of claim 2, the coefficient of friction of the mold part for the belt tooth root surface and the mold part for the belt root surface is made larger than other parts. Since the adhesive is applied to the mold part for the surface and the mold part for the bottom surface of the belt tooth, the mold part for the belt tooth surface and the mold part for the belt tooth bottom surface are The woven fabric becomes difficult to slip and the remaining elongation of the woven fabric in those areas is reliably increased, making it possible to manufacture the above-mentioned toothed belt with a long belt life without variation in quality.

[Brief explanation of the drawing]

1 to 4 show examples of the present invention, FIG. 1 is a perspective view of a toothed belt, FIG. 2 is an enlarged view of the teeth of the toothed belt, and FIG. 3 is a toothed belt molding tool. A cross-sectional view of the main part of the mold, and FIG. 4 is an explanatory diagram of the test device for the running test. FIGS. 5 and 6 are explanatory diagrams of a conventional method of manufacturing a toothed belt. 1...Toothed belt, 6...Woven fabric, 8...Tooth tip surface, 9...
tooth surface, 10... tooth bottom surface, 11... tooth root surface, 12... toothed belt molding mold, 15... belt tooth root surface mold part,
16...Mold section for belt tooth bottom surface.

Claims (1)

[Scope of Claims] 1. A toothed belt in which the belt meshing surface is reinforced with a woven fabric, wherein the warp of the woven fabric extending in the longitudinal direction of the belt is a crimped yarn of synthetic fiber, and the woven fabric is attached to the tooth tip surface. A toothed belt characterized in that when the weft density is 1, the tooth bottom surface has a weft density of 1.5 to 3.0, and the tooth root surface has a weft density of 1.5 to 2.5. 2. In a method for manufacturing a toothed belt in which the belt meshing surface is reinforced with a woven fabric, a tooth bottom surface mold part for molding the belt tooth bottom surface of a toothed belt molding mold and a tooth root surface mold part for molding the belt tooth root surface are used. It is characterized by making the friction coefficient of the mold part about 0.3 to 0.5 higher than other parts, placing woven fabric, tensile material, and unvulcanized rubber in this order on top of it, heating and pressurizing it to produce a toothed belt. Manufacturing method of toothed belt. 3. In a method for manufacturing a toothed belt in which the belt meshing surface is reinforced with a woven fabric, a tooth bottom surface mold part for molding the belt tooth bottom surface of a toothed belt molding mold and a tooth root surface mold part for molding the belt tooth root surface A method for manufacturing a toothed belt, which comprises coating a mold part with an adhesive in advance, placing a woven fabric, an expanded body, and an unvulcanized rubber in order thereon, and manufacturing a toothed belt by heating and pressing.