JPH0248773B2 - HATSUKIBERUTODENDOSOCHI - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a toothed belt transmission.

[Conventional technology]

Conventionally, a transmission device using a toothed belt as a winding device for synchronous transmission has been widely used.

In general, these toothed belts have a cord made of a high tensile strength yarn such as Kevlar with low elongation, a woven fabric, etc. embedded in the back surface of the belt in order to accurately regulate the tooth pitch.

Therefore, since the toothed belt can hardly be stretched by human power, it is necessary to make the distance between the axes of the pulleys variable.

However, toothed belts are becoming widely used in office automation equipment, home appliances, etc. due to their accurate synchronous transmission properties, and in such small precision equipment fields, toothed pulley shafts are used for compactness and ease of assembly. There is a desire to avoid structures with variable distances as much as possible.

Therefore, for small precision equipment, it is proposed that the longitudinal elastic modulus of the toothed belt be lower than that of conventional toothed belts, and the belt be made elastic, thereby omitting the inter-axis adjustment mechanism of the toothed pulley. and is being implemented.

[Problems with conventional technology]

However, as mentioned above, if the longitudinal elastic modulus of the toothed belt is lowered, the transmission capacity will be significantly reduced, making it difficult to transmit a light or ultra-light load such as simply feeding paper.
There was a problem that it could not withstand medium or higher transmission loads such as operating the mechanism.

Therefore, when carrying out high-load transmission, a pulley axis adjustment mechanism is indispensable, and the above-mentioned problem that there is a certain limit to the miniaturization of equipment has been met.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention has been developed to provide a belt that can be easily wrapped around a pulley with a fixed distance between the shafts, even though a toothed belt with high tensile strength is used, and that can be used for high-load transmission. The purpose of this invention is to provide a toothed belt transmission device that can perform the following functions.

[Technology to solve problems]

That is, in the toothed belt transmission device of the present invention, a toothed belt having a pitch circumference somewhat longer than the pitch circumference between the toothed pulleys is wound around two or more toothed pulleys, and The present invention is characterized in that a presser belt that substantially follows the pitch circumference between the toothed pulleys is wrapped around the toothed belt.

[Effect]

In order to wrap a toothed belt embedded with a high tensile strength cord made of Kevlar fiber or the like around a toothed pulley with a fixed center distance, the toothed belt must be longer than the circumference of the pitch between the pulleys.

When such a toothed belt is wound around the toothed pulleys 1, 1, the toothed belt 2 becomes loose as shown in FIG. 1, and transmission is impossible in this state.

Therefore, as shown in FIG. 2, a presser belt 3 is further wrapped around the outer periphery of the toothed belt 2 so as to substantially follow the pitch circumference between the toothed pulleys 1, 1. This causes bagginess only on the inside of the belt.

At this time, it is important to keep the pitch circumference of the toothed belt 2 at a length that does not allow the inwardly flared part to come into contact with the inside of the toothed belt 2 on the opposite side. It is sufficient that the circumferential length of the belt 2 is slightly longer than the pitch circumferential length between the toothed pulleys.

In this invention, the initial tension of the toothed belt 2 is 0 as is clear from the figure, and when a load torque is applied, a tension corresponding to the load is applied only to the tension side as shown in Fig. 3. . That is, when starting or stopping, a tension corresponding to the load is applied only to the tension side and transmission starts, and as the load shifts to a steady state, the tension side tension decreases.

Therefore, no unnecessary tension is applied to the belt.

On the other hand, since the presser belt 3 does not transmit any load, the tension does not decrease over time, and its durability is sufficiently compensated.

More importantly, since the outer side of the toothed belt 2 is pressed by the presser belt 3 and is deformed so as to wrap around the toothed pulley, the number of meshing teeth increases, so even with a weak pressing force, it can be High-load transmission is possible without tooth skipping.

Since the toothed belt 1 and the presser belt 3 in this invention are wrapped together and wrapped around the toothed pulley in an overlapping manner, in order to prevent both from coming off the pulley, the back side of the toothed belt 2 is fixed as shown in FIG. Concave and convex strips 4, 4 may be provided on the inner surface of the presser belt 3 so as to fit into each other in a male-female relationship.

Further, the uneven strips 4, 4 may be formed in plural strips as shown in FIG. In addition to the above-described fitting structure, flanges 5, 5 may be provided on the toothed pulley 1 with a height capable of receiving both, as shown in FIG.

Further, for ease of installation, the presser belt 3 may be an elastic belt with rubber-like elasticity, but it should be made of a high modulus material and slightly longer than the pitch circumference between the toothed pulleys (for example, 0.1mm)
It can also be used as a belt.

In this case, if a lubricant is applied to the contact surface between the toothed belt and the presser belt, mounting will be facilitated.

If the presser belt is made of a high modulus material, when the toothed belt is about to run over the teeth of the toothed pulley, the holding force will suddenly increase, which is convenient because it will reliably prevent skipping during high load transmission. good.

〔Example〕

Example 1 Perimeter of Kevlar fiber embedded as a tensile strength member
As shown in Figure 7, a 3cm diameter endless toothed belt 2 is fixed at 10cm, which is a 3% reduction in the distance between the shafts.
The belt was loosely wound between the driven pulleys 1A and 1B, and an elastic belt with a non-stretched circumference of 28 cm and an elongation rate of 3% at 2 kg was superimposed and fitted over the belt 3.

At this time, the bulge Δd toward the inner surface of the toothed belt
The diameter was approximately 2.8 mm on both the tight and slack sides.

Next, when the brake was applied to the driven pulley 1 so that the load was 5 kg/cm and the driving pulley was driven at 120 rpm, the tension side became straight and the slack side had a bulge of about 5.5 mm. Rotational transmission was carried out without any tooth skipping, and then the load was gradually increased to 10 kg/cm over a period of 5 minutes without any tooth skipping.

Next, a continuous rotation test was performed at 500 rpm under a condition of 2 kg/cm, and no abnormality occurred even after 10 hours had passed.

Example 2 An endless toothed belt with a circumference of 10 cm is wound between the driving and driven pulleys with a diameter of 1 cm, with the distance between the shafts fixed at 3% of the normal distance, and an elastic belt that stretches 3% at 2 kg on the outside. A test was conducted in the same manner as in Example 1, except that a load of 3 kg/cm and a continuous load of 1 kg/cm were applied to the driven pulley, and no tooth skipping occurred at all.

Example 3 A toothed belt with a circumferential length of 40 cm and made of Kevlar fiber as a tensile strength member was loosely wound around a toothed pulley with a triaxial arrangement shown in Fig. 8, and then an elastic belt was wrapped around the outer side of the toothed pulley. A running test was conducted in the same manner as above, but no tooth skipping occurred.

〔effect〕

As explained above, even a toothed belt with no elasticity can be easily wrapped around a pulley fixed between the shafts by working with a presser belt.
Moreover, it becomes possible to perform high-load transmission.

In addition, the belt circumference is not so strictly regulated as long as it is longer than the pitch circumference between the pulleys, so any toothed belt can be used as long as the tooth modules match, making it highly versatile and providing various effects. have

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are explanatory diagrams of the operation of this invention. FIGS. 4, 5, and 6 are explanatory diagrams of other operations of this invention. FIG. 7 is an embodiment of this invention. FIG. 8 is a side view of another embodiment.

Claims (1)

[Claims] 1. A toothed belt having a pitch circumference somewhat longer than the pitch circumference between the toothed pulleys is wound around two or more toothed pulleys, and the toothed belt is further wound around two or more toothed pulleys. A toothed belt transmission device characterized in that a presser belt substantially along the pitch circumference between the toothed pulleys is wound over the top of the belt. 2. The toothed belt transmission device according to claim 1, wherein concavo-convex stripes are formed on the back surface of the toothed belt and on the inner surface of the presser belt so that they can fit into each other in a male-female relationship. 3. The toothed belt transmission device according to claim 1 or 2, wherein the toothed pulley is provided with a flange having a height capable of receiving both the toothed belt and the presser belt. 4. The presser belt is stretchable and has a circumference shorter than the pitch circumference between the toothed pulleys in a non-stretched state. Toothed belt transmission.