JPS6139138Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a toothed belt for power transmission.

Toothed belts are used to synchronize the timing between the driving side and the driven side in the drives of various machines, the transmission parts of automobiles, office equipment, etc. These toothed belts have woven fabric attached along the meshing surfaces for reinforcement. This woven fabric usually uses crimped synthetic fiber threads as the threads extending in the length direction of the toothed belt. When forming a toothed belt,
As shown in FIG. 1, a woven fabric 2, a tensile material 3, and an unvulcanized rubber 4 are placed on a mold 1 having an uneven outer periphery.
This is pressurized and heated to form and vulcanize the toothed belt 5 as shown in FIG. Therefore, woven fabric 2
changes from a nearly flat state as shown in Fig. 1 to a bent state as shown in Fig. 2. Therefore, the woven fabric 2 needs to be able to elongate by 30 to 50%, and the elongation must be able to be performed with low stress. Therefore, crimped yarn is used as the woven fabric so that the woven fabric can be easily stretched with small stress.

By the way, in conventional belts of this type, the elongation of the woven fabric used is comparable to the elongation rate during the above-mentioned molding. In other words, when molding, the woven fabric
% elongation, the elongation of the woven fabric is usually set at about 50% to 55% with some safety factor in mind.

However, in the case of such a toothed belt, the crimped yarn is almost completely stretched when the woven fabric is attached.
There is no difference from ordinary multifilament yarn.

By the way, in order for the woven fabric to have a reinforcing effect, it needs to have a certain degree of thickness when it is attached to the belt. However, as mentioned above, when the crimped yarn is fully stretched, such as a multifilament, the woven fabric becomes thin, cannot provide sufficient reinforcing effect, and is easily worn and has poor durability. Moreover, uncrimped multifilament yarn has poor adhesion to rubber and is easily peeled off.

In view of these circumstances, in the present invention, the woven fabric in areas that are particularly prone to wear is pasted with the crimps not fully stretched to enhance the reinforcing effect and to prevent the reinforcing fabric from peeling off from the rubber. This was prevented.

The present invention will be explained below with reference to the drawings. FIG. 3 shows a toothed belt 5 of the present invention.
A tensile member 8 is inserted in the longitudinal direction into a rubber belt 7 having teeth 6 on its surface, and a woven fabric 2 is adhered to the surface. As shown in FIG. 4, the woven fabric 2 consists of warp yarns 9 extending in the length direction of the belt 5 and weft yarns 10 extending in the width direction, and the warp yarns 9 are crimped yarns of synthetic fibers. The weft is made of ordinary synthetic fibers.

When the woven fabric 2 is attached to the toothed belt 5, the crimped yarn 9 is fully stretched on the top surface 11 of the tooth 6, and the crimped thread 9 is fully stretched on the bottom surface 12 and side surface 13 of the tooth 6. It is pasted without being fully stretched.

To describe an example of the present invention, the length of the toothed belt 5 along the meshing surface is approximately longer than the length of the woven fabric 2.
When the woven fabric 2 is 50% larger, the woven fabric 2 used can be elongated by about 80% with a small stress. Therefore, on the top surface 11 of the teeth 6 of the toothed belt 5, the woven fabric 2 is
It is pasted in a state where it is stretched by ~75%, and the woven fabric 2 is stretched by 30~35% on the bottom surface 12 and side surface 13 of the tooth 6, respectively.
And attach it in a state where it is stretched by about 45-50%.

In a toothed belt, the sides of the teeth 6 receive the greatest force due to friction with the pulleys and are likely to wear out, but in this invention, the sides of the teeth 1
3, the woven fabric 2 is attached without being stretched to its stretching limit, and the warp threads 9 are still in a crimped state. The fabric is therefore thick and able to withstand abrasion well.

Moreover, if a large stress is applied to the woven fabric 2 at the bottom surface 12 of the tooth 6, that force will act in a direction that causes the woven fabric 2 to peel off from the belt body, and the woven fabric 2 may become worn out after long-term use. The fabric 2 peels off from the belt and damage progresses rapidly, but in the present invention, the woven fabric 2 is not sufficiently stretched in this area, and therefore the stress applied thereto is extremely small. Therefore, peeling does not occur rapidly during use, and use can be continued until the woven fabric 2 is completely worn out. Moreover, since the crimped yarn is mechanically bonded to the rubber, it has the effect of increasing adhesive strength.

Furthermore, in the conventional toothed belt, the woven fabric 2
Since the warp yarns 9 are attached in a state where they are stretched to their stretching limit, if stress is applied to the teeth 6 and deforms while the toothed belt is in use, the woven fabric 2 will not be able to follow the deformation. The warp threads 9 may be partially cut off at the base of the teeth 6. Once the warp threads 9 are cut, the cut portion acts as a hook and causes a crack in the rubber of the tooth 6, and as stress is applied repeatedly, the crack grows and eventually the tooth 6 is missing. Something like this happened. However, such a problem does not occur with the toothed belt of the present invention.

In other words, in the toothed belt of the present invention, the warp yarns 9 of the woven fabric 2 are not stretched sufficiently and are attached with crimps remaining, so that when stress is applied to the teeth 6 and the teeth are deformed, The woven fabric 2 can easily follow the deformation, and no excessive tensile stress is applied to the warp yarns 9.
is never severed. Therefore, the cut portion does not become a nick and cause cracks, and can withstand use for a long time.

Note that the degree of abrasion is small on the top surface 11, and the stress applied to the woven fabric 2 acts in the direction of pressing it against the belt body, so there is no problem even if the crimp is attached in a fully extended state. do not have. Rather, considering that it is technically difficult to crimp the warp yarns 9 of the woven fabric 2 violently and increase the elongation rate of the woven fabric 2, it is necessary to sufficiently elongate the woven fabric 2 on the top surface 11. It is preferable to apply the warp in a state in which the warp threads are crimped, shrink the woven fabric 2 on the bottom surface 12 and the side surfaces 13, and increase the degree of crimp of the warp threads.

The length of the woven fabric 2 in the present invention when stretched is 10 to 30 mm longer than the length along the meshing surface of the toothed belt.
It is better to set it to a larger value. If this is less than 10%, the crimp of the warp yarns on the bottom surface 12 and side surface 13 of the teeth 6 will be insufficient, and the effects of the present invention will not be sufficiently achieved. On the other hand, setting it to 30% or more is not preferable because it is not only difficult in terms of manufacturing technology for the woven fabric, but also because the warp threads 9 in the woven fabric are severely crimped and the woven fabric is easily deformed during molding of the toothed belt.

[Brief description of the drawings]

FIGS. 1 and 2 are longitudinal cross-sectional views showing the process of molding a toothed belt. FIG. 3 is a cross-sectional perspective view of the toothed belt of the present invention. FIG. 4 is a longitudinal sectional view of the woven fabric, and FIG. 5 is an enlarged longitudinal sectional view of the toothed belt of the present invention. 2...Woven fabric, 5...Toothed belt, 6...Teeth,
9... Warp thread (crimped thread), 11... Top surface of tooth, 1
2...Bottom surface of the tooth, 13...Side surface of the tooth.

Claims (1)

[Claims for Utility Model Registration] 1. In a toothed belt in which the meshing surface of the belt is reinforced with a woven fabric, the yarn extending in the length direction of the toothed belt in the woven fabric is a crimped yarn of synthetic fiber, and A toothed belt characterized in that the crimped yarn is not sufficiently stretched on the bottom and side surfaces of the teeth of the toothed belt, and the crimped yarn is substantially fully stretched on the top surface of the teeth. . 2. The toothed belt according to claim 1 of the utility model registration claim, characterized in that the stretched length of the woven fabric is 10 to 30% longer than the length along the meshing surface of the toothed belt. .