JPS6243163Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a double-sided toothed belt in which teeth are provided on each of the inner and outer circumferential sides of an endless belt. Double-sided toothed belts generally have a problem that is difficult to avoid due to their manufacturing method, in that the accuracy of the outer circumferential teeth is lower than that of the inner circumferential teeth. In other words, when manufacturing a double-sided toothed belt, for the inner teeth,
Molding can be done by wrapping a canvas and a rubber plate around a cylindrical mold with a tooth-shaped outer surface and applying pressure from the surrounding area under heating, but the outer teeth can be formed by pressure using a mold. cannot be adopted. Therefore, conventionally, an outer tooth member with a tooth profile formed in advance is wrapped around the back surface of the inner tooth portion molded with a mold and vulcanized and bonded, or an unvulcanized rubber sheet is attached to the back surface of the inner tooth portion. A commonly used method is to wrap the material around the material and press-form it using a hard rubber mold. However, in any case, with this method, the accuracy of the outer peripheral teeth, for example, the tooth arrangement and tooth shape, will be uneven compared to the inner peripheral teeth using a mold,
Also, PLD (Pitch Line Difference), which is 1/2 of the difference between the pitch diameter and the outer diameter of a toothed belt pulley, is larger on the outer tooth than on the inner tooth. There is a tendency. Therefore, the teeth on the outer circumferential side are more likely to cause poor meshing with the pulley than the teeth on the inner circumferential side, and in particular, when a tension pulley or the like is meshed with the teeth on the outer circumferential side to cause the belt to run bent, the bending angle As the tooth groove width changes depending on be. In view of this, the present invention makes the tooth rubber on the outer peripheral side teeth softer than the tooth rubber on the inner peripheral side teeth, thereby reducing the resistance when meshing with the pulley and preventing misalignment. By making the canvas thicker than the inner canvas and setting the hardness of the tooth rubber and the thickness of the canvas within a predetermined range, we aim to reduce the wear rate of the outer canvas. To provide a double-sided toothed belt in which the durability of the toothed portions is approximately equal to extend the life of the belt. DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below with reference to the drawings. In Figures 1 and 2, 1 is a double-sided toothed belt in which inner teeth 2 and outer teeth 3 are equally spaced on the inner and outer sides of the belt, respectively. A tensile member 4 is embedded inside. The inner toothed portion 2 is shown on the lower side in FIG. 2 with the tensile member 4 as a boundary, and the outer toothed portion 3 is shown on the upper side. It is formed by The inner tooth rubber 5 and the outer tooth rubber 6 are made of neoprene rubber, and the hardness of the inner tooth rubber 5 is
Hs70~74 degrees, hardness of outer tooth rubber 6 is Hs60~69
The hardness of the outer tooth rubber 6 is the inner tooth rubber 5.
It is about 5 to 10 degrees lower than the actual temperature. Note that a JISA type spring type hardness meter was used to measure the hardness. On the other hand, the inner canvas 7 and the outer canvas 5 have 66
This is a 2/2 twill woven fabric made of nylon that is bonded using an RFL (resorcinol formalin type) adhesive, etc. The thickness of the inner canvas 7 is 0.31 mm, and the thickness of the outer canvas 8 is 0.31 mm. is set to 0.341 to 0.403 mm, and the outer canvas 8 is made approximately 10 to 20% thicker than the inner canvas 7. Therefore, in the double-sided toothed belt 1, PLDt ₁ on the outer circumferential side is larger than PLDt ₂ on the inner circumferential side, as in the case of conventional belts. Note that the tensile body 4 is a glass cord having a diameter of 0.752 mm. FIG. 3 shows a double-sided toothed belt 11 in which the structure of the toothed rubber on the outer peripheral side is different from that shown in FIG.
is made of rubber material with a Hs of 60 to 69 degrees, and has a tensile strength of 14
The base layer portion 16b located on the side is made of a rubber material having the same hardness as the tooth rubber 15 of the inner tooth portion 12, that is, Hs70.
Constructed of ~74 degree rubber material. Inner canvas 1
7. Other structures such as the outer canvas 18 and the tensile body 14 are the same as those shown in FIG. Next, the reasons for limiting the hardness of the tooth rubber and the thickness of the canvas will be explained based on test results. FIG. 4 shows a belt running test device, and the test conditions are as shown in Table 1.

[Table] First, regarding the influence of the hardness of the tooth rubber on the wear of the canvas, the hardness of the inner tooth rubber is assumed to be Hs72 degrees,
Figure 5 shows the results of measuring the wear rate while varying the hardness of the outer tooth rubber. Other specifications of the sample materials are shown in Table 2. Note that the running time of the belt is 50 hours.

[Table] The graph in Figure 5 shows that the hardness of the outer tooth rubber is
When Hs is 62 to 67 degrees, that is, when the hardness is 5 to 10 degrees lower than the hardness of the inner tooth rubber, the wear rate of the outer canvas is as low as 40% or less. In some cases, the effect will be smaller. Next, regarding the influence of the thickness of the canvas on the wear of the canvas, Figure 6 shows the results of measuring the wear rate by setting the thickness of the inner canvas to 0.31 mm and varying the thickness of the outer canvas. The specifications of the sample materials are shown in Table 3. The running time of the belt was 50 hours, and the tooth rubber was made of rubber material with a Hs of 74 degrees on both the inner and outer circumferential sides.

[Table] In the graph in Figure 6, the thickness of the outer canvas is 0.341.
~0.403mm, that is, when it is about 10 to 30% thicker than the inner canvas, the wear rate of the outer canvas is as low as 40% or less, and it is less than 10% or
If it exceeds 30%, the effect is small. Therefore, the specifications of the double-sided toothed belt when the hardness of the toothed rubber and the thickness of the canvas are combined at the most preferable values are as shown in Table 4, and the results of the belt running test with this combination are shown in Table 4. It is shown in Figure 7.

[Table] In Figure 7, the wear rate of the canvas after running for 150 hours is about 50% on the inner circumference and about 65% on the outer circumference, and there is no big difference between the inside and outside. Figure 8 shows a conventional double-sided toothed belt, that is, the hardness of the tooth rubber on both the inner and outer sides is Hs72±2.
This shows the results of a running test using a belt with the same canvas thickness as 0.31 mm.
The diameter is 0.686mm, and the outer circumference is 0.72mm. In Fig. 8, the wear rate of the canvas on the outer circumference is 5% compared to that on the inner circumference.
It is about twice as large, and there is a large difference in life between the inner and outer circumferential sides. The wear of the canvas can be considered as the lifespan of the belt, and the life of this conventional example is considered to be about 75 hours when the outer canvas wears out. Note that the broken line shown in Figure 8 represents the results of a test where the outside diameter of the pulley was changed and the PLDs on the inner and outer sides were approximately equal.In this case, the lifespan was approximately the same on the inner and outer sides. be equal. As can be seen by comparing the graphs in FIGS. 7 and 8 above, the belt according to the present invention has a lifespan approximately three times longer than that of the conventional belt. In this way, the reason why the product of the present invention has excellent durability is that the outer tooth rubber is made softer than the inner tooth rubber, which reduces the resistance when the outer tooth meshes with the pulley. This is believed to be due to the fact that defects were prevented and the abrasion resistance was improved due to the thicker outer canvas. Therefore, the double-sided toothed belt 1 according to the present invention,
11 can be applied as a power transmission belt for driving auxiliary equipment of an automobile, as shown in FIGS. 9 to 11. 9 to 11, 31 is a crankshaft, 32 is a camshaft, 33 is an AC generator, 3
4 is a water pump, 35 is a balancer shaft, 36 is an air compressor, and 37 is a pulley connected to the power steering.
Further, 38 is an idler. As described above, according to the present invention, the hardness of the outer tooth rubber is made lower than that of the inner circumferential side, and the outer circumferential canvas is made thicker than the inner circumferential side, so that the outer tooth part and the pulley are The excellent effect of reducing the occurrence of misalignment and making the durability of the outer circumferential tooth portion and the inner circumferential tooth portion substantially equal, resulting in an improvement in the life of the belt can be obtained. Although the present invention relates to a double-sided toothed belt, the technical concept of changing the physical properties between the inner and outer circumferential sides of the belt can be applied to other belts such as V-belts.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention; FIG. 1 is a perspective view schematically showing a double-sided toothed belt, FIG. 2 is a longitudinal sectional view of the same essential parts, and FIG. 3 is a longitudinal sectional view showing another embodiment. Figure 4 is a longitudinal cross-sectional view showing a belt running test device, Figure 5 is a graph showing the relationship between tooth rubber hardness and canvas wear rate, and Figure 6 is a graph showing the relationship between canvas thickness and canvas wear rate. 7 and 8 are graphs showing the durability of the belt, and FIGS. 9 to 11 are longitudinal cross-sectional views showing examples of application of the double-sided toothed belt. 1, 11...Double-sided toothed belt, 2, 12...Inner circumferential tooth portion, 3,13...Outer circumferential tooth portion, 5,15...
...Inner tooth rubber, 6,16...Outer tooth rubber,
7, 17... Inner circumference side canvas, 8, 18... Outer circumference side canvas.

Claims (1)

[Scope of utility model registration request] In an endless belt in which the inner and outer teeth are arranged at equal intervals around the entire circumference of the belt, the toothed rubber surface is covered with canvas and the inner and outer teeth are arranged at equal intervals on the inner and outer sides of the belt. The hardness of the tooth rubber on the tooth part is 5 to 10 degrees lower than the tooth rubber on the inner tooth part, and the thickness of the canvas on the outer tooth part is 10 to 30% that of the canvas on the inner tooth part.
A double-sided toothed belt characterized by its thick structure.