JPS6260571B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a multi-coupled power transmission belt for general industrial use that spans between a prime mover and a pulley on a driven machine side to transmit power.

[Prior art and its problems]

First, FIG. 1 shows a basic belt transmission mechanism. In the figure, 1 is the driving pulley, 2 is the driven pulley, and 3 is the belt wrapped between pulleys 1 and 2. During operation, the upper side of the belt is the tension side and the lower side is the slack side, and the belt and pulley surface are It is well known that power is transmitted by the frictional force between the two. Furthermore, in general industrial machines that transmit relatively large amounts of power, a plurality of belts are usually used, and in this case, V-belts with less slippage and high transmission efficiency are widely used. By the way, when the belt transmission mechanism is operated,
Vibration is observed in the belt transmission mechanism, and vibration noise may be particularly strong if a gear device or the like is also incorporated into the power transmission system. In addition, this vibration noise sometimes changes to a humming sound and gives a feeling of anxiety to operation and maintenance personnel. According to the inventor's study of the mechanism by which such noise is generated, the cause is that the tensile elasticity of each belt is not uniform over the entire length of the belt, as detailed below. It turned out that there was. That is, using a commercially available belt as a sample, the following tests were conducted to examine the tensile elasticity distribution over its entire length. First, as shown in Fig. 2, one belt 3 is divided into 16 equal parts and each position is numbered to serve as a gauge point. Furthermore, gauge points '~' are placed at equal intervals from a point away from the gauge point by a distance corresponding to the distance l between the axes of pulleys 1 and 2, and this belt 3 is connected between pulleys 1 and 2 as shown in Fig. The pulleys are rotated from the drive side while applying tension to the belt 3 by applying a force P to the pulleys 1 and 2. When the belt gauge point reaches point x shown in Figure 1, measure the length of the belt between the gauge point and
l is determined, and from this measured value, the average tensile elasticity C=Δl/P between the gauge point and '' is calculated. By performing similar operations for each point of each gauge point,
The tensile elasticity distribution shown in FIG. 3 is obtained. As is clear from FIG. 3, the tensile elasticity of the belt is not uniform over its entire length, and there are regions of high elasticity and regions of low elasticity. Although the degree of this tendency varies, it has been confirmed from the test results conducted by the inventor that each commercially available belt exhibits its own unique elasticity distribution. The reason for this is presumed to be the following. That is, the manufacturing method of the above-mentioned V-belt is as shown in FIGS. 4 to 6. First, a wide unvulcanized rubber 5 for the base is wrapped around the drum 4, and then a wide base layer of unvulcanized rubber 5 is wrapped around the drum 4. Rubber 6 for reinforcement of bending rigidity is wrapped around it. Next, the core wire cord 7 is continuously wound spirally at narrow pitch intervals and then vulcanized. Next, the V-belt 3 is completed by cutting it into rounds with a fixed width along the broken line shown in FIG. 5, and finally wrapping the cloth 8 around the circumferential surface. In this way, a belt 3 with a core wire cord made by cutting a wide material into rings has a large number of spirally wound cords 7 in some places and a small number in other places depending on the location along the circumferential direction. Yes, and this cord is interrupted at some point along its length. Naturally, seams also exist because the rubber band is wrapped in the manufacturing process. Moreover, since the core cord 7 shares a considerable proportion of the tension acting on the belt, as a result, the belt 3 has regions of high tensile elasticity and regions of low tensile elasticity along the circumferential direction. By the way, in the belt transmission mechanism shown in FIG. 1, it is well known that the torques T1 and T2 transmitted between the pulleys 1 and 2 by the belt 3 are expressed by the following equation. T1 = R1 (F1 - F2) T2 = R2 (F1 - F2) Note that F1 and F2 are the belt tensions on the tight side and slack side, respectively, and R1 and R2 are the radii of pulleys 1 and 2. On the other hand, regarding the entire length of the belt 3 shown in FIGS. 1 and 2, let A be the region where the average elasticity is small in the region of length l, and B be the region where the average elasticity is large, and the elasticity in the A and B regions, respectively, is C1. , C2. Note that when no tension is applied to the belt, the lengths of the A and B regions are both l, and as seen in the measurement results in Figure 3, the A and B regions of one belt are generally They are located on opposite sides of the belt. Here, belt 3 is stretched over pulleys 1 and 2,
When belt 3 is rotated while applying tension at the same time as described above, each elongation of the belt △ when area A and area B come to the tension side of the belt, respectively.
l is F1C1, F1C2 for belt length l,
This state is illustrated in FIGS. 7 and 8. On the other hand, when the A region and the B region come to the slack side of the belt, the elongation Δl of the belt becomes F1C1 and F2C2 with respect to the belt length l. From this, it can be seen that the A region where elasticity is small on the tension side of the belt 3,
The amount of elongation △l of the belt changes depending on the state where the B region with high elasticity is on the slack side and the state where the B region is on the tension side of the belt and the A region on the slack side, and the amount of elongation of the belt is The difference, that is, the angle Δθ (radians) in FIG. 9, is expressed by the following equation. △θ={(F1C1−F2C2)−(F1C2−F2C1)}/R2 = (C1−C2)(F1+F2)/R2 In other words, if the difference between the elasticities C1 and C2 in areas A and B is large, △θ becomes large, Moreover, this change in elongation occurs repeatedly during the revolution period. Note that the revolution period of the belt is expressed as L/v, where v is the circumferential speed of the belt and L is the total length of the belt. As a result, when the belt transmission mechanism is in operation, the 10th
A torsional vibration with an amplitude Δθ and a frequency v/L as shown in the figure is generated. In this case, the vibration frequency is, for example, belt length 1.5 m, pulley diameter
When calculating using a 150mm belt transmission mechanism as a model, the rotation speed is 10.5Hz at 2000r.pm and 21Hz at 4000r.pm. As mentioned above, when vibration occurs due to the difference in elongation of the belt during operation, the natural frequency of the rotating shaft, gears, etc. that make up the transmission mechanism is equal to the excitation frequency generated by the belt mentioned above. If they match, the resonance effect will result in large torsional vibrations, which will generate large noises, especially if there is a gear system. Furthermore, if the natural bending frequency of the rotary shaft of the pulley and the excitation frequency match and resonate, there is a risk of increased vibration and damage to the shaft. Now, the above description has been made regarding the case where there is only one belt, but in the case of a multi-belt in which multiple belts are wound in parallel as in an actual transmission device, the state of vibration becomes even more complicated. That is,
If two belts are placed in parallel on the same pulley, the elastic distribution on the circumference of each belt will be the first depending on the relative position of the two belts.
It will look like (a) and (b) in Figure 1 or Figure 12. In the case of Fig. 11, the elasticity of each belt is
When (a) and (b) are superimposed topologically, the composite elasticity of the two belts becomes as shown in (c), and the difference D between the maximum and minimum elasticity values becomes large. On the other hand, in the case of Figure 12, the elasticity distributions (a) and (b) cancel each other out topologically, so the composite elasticity is as shown in (c), and the difference D between the maximum and minimum elasticity values becomes small. , averaged over the entire length. On the other hand, as is well known, the belt moves while slipping locally between it and the pulley due to creep that occurs during operation.In this case, the amount of slip varies depending on the individual belt, so in actual operation The relative position of each belt in the circumferential direction changes with time, and the states shown in FIGS. 11 and 12 occur alternately and repeatedly. As a result, torsional vibration whose amplitude changes with time occurs on the driven pulley shaft as shown in FIG. 13. Furthermore, as the number of belts used increases, more and more complex and irregular torsional vibrations occur, and the resulting vibration noise becomes a whirring noise, which gives a sense of anxiety to machine maintenance personnel.

[Purpose of the invention]

This invention has been developed in view of the above points, and is a method to skillfully reduce the excitation force generated in multiple belts due to the uneven tensile elasticity distribution unique to each belt, which is unavoidable due to the belt manufacturing method as described above. It is an object of the present invention to provide a multi-coupled power transmission belt that can suppress the above.

[Key points of the invention]

In order to achieve the above object, the present invention measures the tensile elasticity distribution over the entire length of each belt using the method described in FIGS. By deviating the positions of the large and small elastic regions of each belt in the circumferential direction so as to cancel each other out, the composite elastic distribution of the entire multi-belt can be made almost uniform over the entire length. The relative positions of the respective belts are set so that the belts are aligned with each other, and the belts are integrally connected to each other through the connecting means while maintaining this relative position, thereby reducing torsional vibration of the shaft that occurs during operation, and secondary vibrations. This is designed to reduce the vibration noise generated by the engine.

[Embodiments of the invention]

The configuration and assembly procedure of the present invention will be described below based on the illustrated embodiments. To assemble the multi-coupled power transmission belt according to the present invention, first, the tensile elasticity distribution over the entire length of each belt constituting the multi-coupled belt is actually measured and determined. The principle of this method will be explained in the first part.
Although described with reference to FIGS. 3 to 3, actual measurement is actually performed using a stroboscope-type measuring device as shown in FIG. 14 as an example. In the figure, 9 is a drive motor, 10 is a flywheel as a driven load, 1
1 is a pickup for detecting rotational speed or torque, 12 is a measuring device, 13 is an indicator thereof, and 14 is a strobe. A reference belt 15 whose elastic distribution is known in advance is stretched between pulleys 1 and 2, and strobe reference marks 15a are attached at predetermined positions on the belt. Here, marks 3a are attached to multiple locations on the circumference of the belt to be inspected 3 using a chiyoke or the like, and one by one the reference belt 15 is
The motor 9 is operated by connecting the pulleys 1 and 2 side by side. In this case, when the elastic distributions of the reference belt 15 and the belt to be inspected 3 match in phase as shown in FIG. Appears on the 13th. On the other hand, when the elastic distribution shifts so as to offset each other topologically as shown in Figure 12,
The indicator 13 indicates the minimum value. At this time, the light source of the stroboscope is made to flicker in synchronization with the revolution speed of the belt, and the relative position of the reference mark 15a of the belt 15 and the mark 3a of the belt to be inspected 3 is detected, thereby making the elastic distribution of the reference belt 15 a reference. In contrast to this, the elasticity distribution of the belt 3 to be inspected is determined. In addition, for the purpose of belt assembly work to be described later, indication marks indicating the positions of the maximum and minimum elasticity points are marked on the belt. In addition to the stroboscope method described above, there is also a method of determining the tensile elasticity distribution of the belt to be inspected using a rotary encoder method. Next, a procedure for assembling a multiple coupled power transmission belt using individual belts whose elastic distributions have been determined by the above measurement method will be described. First, a predetermined number of belts are lined up, and, relying on the indication marks indicating the areas of high elasticity and areas of low elasticity marked in the above process for each belt, the circumference is adjusted so that each area does not match topologically among the multiple belts. The relative positions of the belts are determined so that the composite elasticity distribution of each belt is substantially uniform over the entire circumference of the belt as a multiple belt. In this case, when the multi-belt is composed of two belts, the maximum elasticity point and the minimum elasticity point match topologically with respect to the elasticity distribution unique to each belt, as shown in Fig. 15. Determine the relative positions of the belts so that they line up. As a result, the composite elasticity distribution of the two belts becomes uniform over the entire length L as shown by T. Similarly, the multiple belt is 3
In the case of this belt, as shown in Fig. 16, the belts are rearranged and the relative positions of the belts are set so that the composite distribution T of the unique elasticity distribution of each belt is uniform over the entire length L of the belt. do. That is, the relative positions of the belts using the method described above are determined in the same way as the drawing method of vector composition. Therefore, even if the individual elasticity distributions and elasticity values of the three belts vary, by performing appropriate relative positioning using the method described above, the composite elasticity distribution as a multi-belt can be maintained over the entire length range. This means that it can be made almost uniform. Once the relative position of each belt in the multiple belt is determined as described above so that the elasticity distribution over the entire length is uniform, next, while maintaining this relative position, the multiple belt is configured via the connecting means. The belts connected to each other are mechanically and integrally connected to each other, thereby assembling a multiple-coupled power transmission belt. Next, several embodiments of connecting means for integrally connecting a plurality of belts while maintaining their relative positions are shown in FIGS. 17 to 20. In each figure, numerals 3 to 3 indicate three belts constituting a multiple belt whose relative positions in the circumferential direction have been determined through the process of equalizing the elasticity distribution described above. In order to maintain the relative positions of the belts 3 to 3 and integrally connect each belt to each other, in the embodiment shown in FIG.
A wide back band 1 on the back side spanning the entire length of the belts 3 to 3 as a connecting means.
6 is attached, and the three belts are integrally connected via this back band 16. Incidentally, this back band 16 can also be made of an unvulcanized material and stacked on each belt and vulcanized to integrate them. In the embodiment shown in FIG. 18, a row of teeth 17 is formed in advance on the back surface of each belt 3 to 3 to protrude along the longitudinal direction as a connecting means, and with the relative positions between the belts determined, A wide back band 18 is fitted over the tooth rows 17 of each belt 3-3, and thereby the belts 3-3
It is a combination of two parts that are integrally connected to each other. In this embodiment, the belt can be replaced or rearranged one by one, and as mentioned earlier, indication marks are placed on the circumference of the belt to indicate the maximum elasticity points and the minimum elasticity points based on the elasticity distribution measurement results. By keeping these marks in mind, it is also possible to assemble or replace the multi-coupled power transmission belt at the site of use, relying on this mark. In the embodiment shown in FIG. 19, rows of teeth 17 protruding from both sides of the belts 3 to 3 are formed in advance on each of the belts 3 to 3 as a connecting means, and the rows of teeth 17 are engaged with each other after setting the relative positions between the belts. In this example, the first
As in the embodiment shown in FIG. 8, the multiple coupling type transmission belt can be assembled or replaced at the site of use. In the embodiment shown in FIG. 20, a large number of screw holes 19 are drilled along the longitudinal direction on the back surface of each belt 3 to 3, and after the belts are positioned relative to each other, the belts straddle each belt 3 to The connecting pieces 20 are integrally connected by screwing and fastening the connecting pieces 20 at a plurality of locations. As in each of the above embodiments, after performing an operation to equalize the elasticity distribution of a multiple belt in which a plurality of belts are combined, each belt is connected to each other by a connecting means while maintaining the relative position between the belts. By being integrally connected, each belt 3 to 3 will not slip separately between the pulleys during operation, and therefore, an even distribution of composite elasticity will always be maintained as a multiple belt. .

【Effect of the invention】

As described above, the present invention measures the tensile elasticity distribution over the entire length of each of the plurality of belts constituting the multiple belt, and based on this, when assembling and configuring the multiple belt, each belt is By relatively displacing the large elasticity region and the small elasticity region in the circumferential direction, positioning is performed so that the synthetic tensile elasticity distribution as a multiple belt is approximately equalized over the entire length, and this relative position Each belt is integrally connected to each other by a connecting means while maintaining the same, thereby assembling a multiple-coupled transmission belt,
Therefore, by mutually compensating for the uneven tensile elasticity inherent to each belt, which is unavoidable due to the belt manufacturing method, it is possible to obtain a multi-coupled power transmission belt with an even tensile elasticity distribution. An excellent effect can be obtained in that torsional vibrations occurring in the belt transmission system due to elastic distribution and secondary vibration noise can be suppressed.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the principle configuration of the belt transmission mechanism, Fig. 2 is a developed view of the belt, Fig. 3 is a tensile elasticity distribution diagram of the belt in Fig. 2, and Figs. 4 to 6 are V-belts with core cords. A cord winding state diagram, a partial sectional view of an intermediate finished product, and a perspective sectional view of a completed belt are shown in the order of the manufacturing process. Figure 10 is a waveform diagram of torsional vibration applied to the driven shaft during operation with a single belt, Figures 11 and 12 are tensile elasticity distribution diagrams at different belt relative positions of a double belt, respectively, and Figure 13 is a waveform diagram of torsional vibration applied to the driven shaft during operation with a single belt.
A waveform diagram of torsional vibration applied to the driven shaft during operation with a continuous belt, Fig. 14 is a configuration diagram of a stroboscope-type tensile elasticity distribution measurement device, and Figs. 15 and 16 are for a double belt and a triple belt, respectively. FIGS. 17 to 20 are perspective sectional views of different embodiments showing the structure of communication means between belts according to the present invention. 1, 2... Pulley, 3, 3~3... Belt, 7... Core wire cord, 16... Back band,
17...Tooth row, 18...Toothed back band, 2
0...Connection piece.

Claims (1)

[Scope of Claims] 1. A multi-coupled power transmission belt formed by connecting a plurality of belts in parallel and integrally with each other, which is based on the tensile elasticity distribution over the entire length of the belt determined by actual measurements for each belt. In addition, by shifting the positions of the regions of large and small tensile elasticity in each belt relative to each other in the circumferential direction, the synthetic tensile elasticity distribution as a multiple belt becomes almost uniform over the entire length. 1. A multi-coupled power transmission belt characterized in that the relative positions of the belts are determined as such, and the belts are integrally connected to each other via a connecting means while maintaining this relative position. 2. The belt according to claim 1, wherein each belt is a core cord-containing belt. 3. The belt according to claim 1, characterized in that each belt is marked with indicator marks on its circumference indicating the maximum and minimum points of tensile elasticity determined by actual measurement of the tensile elasticity distribution. Multiple connection type power transmission belt. 4. In the belt according to claim 1, a wide back band is attached all around the back side of each belt as a connecting means, and each belt is integrally connected to each other via this back band. A multi-coupled power transmission belt with special features. 5. In the belt according to claim 1, each belt is provided with a row of teeth protruding from the back side as a connecting means, and a back band with a row of teeth is fitted over the entire circumference of each belt. A multi-coupled power transmission belt characterized in that each belt is integrally coupled to each other via this back band. 6. In the belt according to claim 1, a row of teeth protruding from both sides of each belt is formed as a connecting means, and the rows of teeth are engaged with each other to integrally connect each belt. A multi-coupled power transmission belt with special features. 7. The belt according to claim 1, characterized in that connecting pieces are fixed across the belts at a plurality of locations on the belt, and the belts are integrally connected to each other via the connecting pieces. Multi-coupled power transmission belt.