JPS5952123B2 - Belt conveyor drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving device for a belt conveyor, and in particular on electric roads and escalators, when a passenger rides on the belt and steps, the belt and steps move in the same direction and at the same speed. This invention relates to a handrail drive device.

First, a schematic configuration of a handrail drive device in an escalator will be explained with reference to FIGS. 1 and 2.

In Fig. 1, 1 is a movable handrail, and this handrail 1 is located at the escalator's boarding/descending ends A and B, the drive wheel 2 of the handrail 1 and its front and back positions E and F, and the tensioning device 3 of the handrail 1 and its front and rear positions C. .

10 is a step, and 11 is a presser roller.

As shown in FIG. 2, an endless friction body 12 made of rubber or the like having a large coefficient of friction is attached to the outer peripheral surface of the drive wheel 2 with a plurality of screws 13.

By the way, it has been confirmed through experiment 1 that the driving force of such a driving device, even for something rigid like a handrail, can be calculated using the following equation in the same way as for a general belt.

1 π: eμ・θ・・・・・・・・・(1) 'r1'r2='r2(e"" 1) ==F...
・”(2) T1+T2-2To...(3) Here, T1: Tension on the tight side of handrail 1 T2: Tension on slack side of handrail 1 To: Initial tension on handrail 1 e: 2,718... ... μ: Coefficient of friction between the handrail and the drive wheel θ: Wrap angle between the handrail and the drive wheel F: Driving force of the handrail On the other hand, the running resistance of such a thing increases as it has more bends, and at low temperatures such as in winter. , the surface rubber used in the handrail 1 hardens and its flexibility decreases, increasing the bending resistance at the above-mentioned bending points.

This bending resistance is greatest when the handrail 1 is activated.

In other words, the surface rubber used for the handrail 1 hardens while being bent and tends to be stable in the state it is in when it is stopped, and this stable state is broken when it is started, so the handrail 1 has the greatest resistance force. That is why it is demonstrated.

This tendency becomes stronger as the stopping time becomes longer and as the temperature becomes lower.

For this reason, at the time of startup, a situation occurs in which running resistance is greater than the driving force described above and startup is not possible, or slipping occurs between the handrail 1 and the driving wheel 2, and the handrail 1 is at the same speed as the steps 10. The vehicle did not run, which caused a safety problem.

In order to eliminate this phenomenon, it is necessary to increase the driving force or reduce the running resistance.

In order to increase the driving force, the above (耘(2), (3)
) As can be seen from the equation, it is conceivable to increase the initial tension applied to the handrail 1, but this is not preferable in terms of the life of the handrail.

Next, it is conceivable to increase the wrap angle θ between the handrail 1 and the driving wheel 2, but there is a limit due to the space of the driving device and the building.

Therefore, the remaining means to increase the driving force is to increase the coefficient of friction between the handrail 1 and the handrail drive wheel 2.

Conventionally, chloroprene rubber has been used as a material for the friction body 12 attached to the outer peripheral surface of the handrail drive wheel 2.

Chloroprene rubber was used because it has a relatively high coefficient of friction, durability, and abrasion resistance that does not change over time.

However, according to experimental results, chloroprene rubber has the characteristic that the coefficient of friction decreases when the temperature decreases, which is clearly an extremely inconvenient drawback compared to the above-mentioned running resistance of the handrail that increases as the temperature decreases. It became.

The present invention has been made in view of these points, and its object is to provide a drive device for a bell l-conveyor that has a high coefficient of friction even at low temperatures and is highly reliable.

In order to achieve this object, the present invention uses natural rubber and butadiene rubber as materials for the friction body provided on the outer periphery of the drive wheel.
Styrene-butadiene rubber, or butadiene rubber and styrene-butadiene rubber are mainly blended, and the blending ratio of natural rubber in these is 50 to 90% by weight, and the rubber hardness is 50 to 70 in terms of Hs hardness in JIS-6301.
It is characterized by the use of highly refined ingredients.

Hereinafter, an embodiment in which the present invention is applied to a moving handrail drive device for an escalator will be described.

The drive mechanism of the handrail drive device and the structure of the drive wheel are the same as those shown in FIGS. The main components of the materials used for the friction body 12 provided on the outer circumferential surface were selected from natural rubber (NR), butadiene rubber (BR), and styrene-butadiene rubber (SBR) through the experimental study described below.
, or a suitable combination of butadiene rubber and styrene-butadiene rubber (BR+5BR).

First, at room temperature, the rubber hardness (Hs in JIS-6301, rubber hardness measured by heating rubber physical test method) is 6.
The friction coefficient μ of each of these materials at 6 degrees is shown in FIGS. 3 to 5.

In each of these figures, the horizontal axis is the blending ratio (wt%) of NR and BR, 5BR1 or BR+SBR, and the vertical axis is the friction coefficient μ
It shows.

As seen in each of these figures, the higher the proportion of natural rubber, the higher the coefficient of friction, which is consistent with the tendency generally known as adhesive strength.

In contrast, the conventionally used chloroprene rubber (
The friction coefficient of CR (100% by weight) is about 1.05, which is smaller than the friction coefficient of each of the above-mentioned materials.

However, this applies when the contact surface between the friction body 12 and the handrail 1 is at room temperature, and it has been known that when the temperature of the contact surface changes, the friction coefficient changes as shown in FIG. 6.

In other words, as shown by curve A, the friction coefficient of chloroprene rubber changes significantly depending on the temperature of the contact surface;
NR/BR (mainly blended with natural rubber and butadiene rubber) is curve B (40/6ONR/BR1, that is, the main blending ratio is 40% natural rubber and 60% by weight of butadiene rubber), and curve C (70/3ONR/BR). As shown, it hardly changes.

This means the following:

That is, in the case of chloroprene rubber, if a slip occurs between the friction body 12 and the handrail 1 due to insufficient driving force at startup, the frictional force may generate heat and increase the friction coefficient.

In this case, even if the handrail 1 slips immediately after startup, the handrail 1 will eventually move and the vehicle will often reach steady running.

However, if such a situation is repeated, the surface of the friction body 12 will deteriorate due to heat generation, and the initial friction force will no longer be obtained, eventually making it impossible to start.

Furthermore, as mentioned above, if the handrail 1 has a tendency to bend at low temperatures, the contact pressure between the handrail 1 and the friction body 12 will decrease.
It does not generate heat even if it slips, and in this case it will not start.

Therefore, at low temperatures when driving force is most needed, 40/6QN
In terms of R/BR, it can be said that it has better properties compared to chloroprene rubber.

Next, when the friction coefficient of the friction body 12 is increased to increase the driving force, the stress applied to the cross section of the friction body 12 also increases.

On the other hand, as shown in FIG. 2, the friction body 12 is attached to the outer peripheral surface of the handrail drive wheel 2 with screws 13, and the distance between the screws is generally about 30 degrees.

In contrast to the friction force transmitted by the conventional friction body 12 made of chloroprene rubber at this thread interval, the friction force is transmitted by the friction body 12 made of NR/BR rubber with a large friction coefficient as described above. The frictional force generated increases, and the driving force applied to the thread gap also increases.

Therefore, it is necessary to transmit this increased driving force between the friction body 12 and the handrail drive wheel 2, but the friction coefficient between the friction body 12 and the handrail drive wheel 2 is the same as the friction coefficient between the friction body 12 and the handrail 1. , the frictional force between them is small, and most of the driving force is transmitted by the screw 13 and the friction body 12, so that a large tension acts on the friction body 12.

In view of the above, the coefficient of friction between the friction body 12 and the handrail 1 should preferably have a value that allows activation at low temperatures.

This value can be found from equation (2) above, and the running resistance (T
IT2) varies depending on the escalator model and installation location.

Therefore, an appropriate friction body 1 is selected depending on the expected value of running resistance.
2 materials will be selected.

Next, FIG. 7 shows the relationship between rubber hardness and friction coefficient of 60/4ONR/BR.

From this figure, the coefficient of friction is greatly affected by the hardness of the rubber.
It can be seen that the lower the rubber hardness, the larger the value.

Here, the rubber hardness is about 50 degrees (Hs in JIS-6301), and the elongation of the friction body 12 becomes large.
As the friction body 12 and the driving wheel 2 become separated, the stress acting on the cross section of the friction body 12 increases as described above.

In addition, if the rubber hardness is 70 degrees or higher, the friction coefficient will be lower than the 1.3 degree required in cold weather, so the practical hardness is in the range of 50 to 70 degrees, preferably 55 to 70 degrees.
The range is about 65 degrees.

The above-mentioned NR/BR blending ratio 1. The relationship between rubber hardness and friction coefficient is summarized in Figure 8.

Considering only the driving force, the higher the friction coefficient μ, the better, but as mentioned above, considering the strength of the rubber, μ = 1
．． The upper limit is about 7.

Further, in cold weather, μ=1.3 is necessary, so the practical range of the friction coefficient is 1.3 to 1.7.

Regarding the NR/BR blending ratio, natural rubber is 90% by weight.
If the ratio exceeds 50% to 90% by weight, the abrasion resistance decreases, and as the proportion of natural rubber decreases, the coefficient of friction also decreases. Therefore, a natural rubber blending ratio of 50 to 90% by weight is a practical range, and a desirable range is a natural rubber blending ratio of 50 to 90% by weight. The ratio is 60 to 80% by weight.

Therefore, it can be said that it is desirable to use rubber hardness in the hatched range of 60 to 80/40 to 2 ONR/BR and a rubber hardness of 55 to 65 degrees.

In addition, the above-mentioned NR/BR actually contains vulcanization aids, auxiliary agents, etc. in addition to the main ingredients, natural rubber and butadiene rubber. It is shown in Table 1.

Next, depending on the running resistance value described above, select an appropriate friction body 12.
An experiment was conducted to select the material for this purpose.

The material of the friction body 12 that has the friction coefficient required for escalators currently installed under the most severe conditions is 80%
~90/20~10NR/BR, so when driving force was applied repeatedly to this material, it was cut after about 1500 times.

This is because the stress applied to the friction body 12 is high as described above, and in order to use this friction body 12 for a long period of time, it is necessary to reduce the friction force between the handrail drive wheel 2 and the friction body 12 by some means. It is necessary to make the stress on the friction body 12 smaller.

Possible means for this include, for example, reducing the distance between the screws 13, or providing unevenness 14 on the outer periphery of the drive wheel 2 as shown in FIG.

There are few special cases like the above, and generally it is 60 to 80/
It has a friction coefficient that can be activated sufficiently at about 40 to 2 ONR/BR, and no abnormality was observed even when the driving force was repeatedly applied up to 3000 times in this range.

If the friction body 12 made of natural rubber mixed with butadiene rubber is adopted as described above, the driving force of the handrail 1 can be increased without reducing the reliability of the friction body 12, and the escalator can be easily moved without slipping. safety can be improved.

The value of the friction coefficient of the friction body 12 is almost determined by the blending ratio of natural rubber, so instead of butadiene rubber, use styrene-butadiene rubber, which has almost the same characteristics, or natural butadiene rubber and styrene-butadiene rubber. Even when mixed with rubber, the same effect can be obtained.

As explained above, according to the present invention, the driving force of the belt can be significantly increased without reducing reliability.

[Brief explanation of the drawing]

Figure 1 is a schematic overall side view of the escalator, Figure 2 is the first
The enlarged sectional views showing the drive wheel part in the figure, Figures 3 to 5 are NR/BR, NR/5BR1 and NR/BR1S.
Characteristic diagram showing the relationship between BR compounding ratio and friction coefficient, Figure 6 is a characteristic diagram showing the relationship between contact surface temperature and friction coefficient, Figure 7 is a characteristic diagram showing the relationship between rubber hardness and friction coefficient, Figure 8 9 is a characteristic diagram showing the relationship between compounding ratio, rubber hardness and coefficient of friction, and FIG. 9 is a partially enlarged sectional view showing an example of a handrail drive wheel suitable for the present invention. 1...Movable handrail, 2...Driving vehicle, 12
...Friction body, 13...Screw, 14...
...Uneven parts.

Claims (1)

[Claims] 1. A belt conveyor drive device in which a friction body is provided on the outer periphery of a drive wheel, and this friction body is brought into contact with the back surface of the belt conveyor to frictionally drive the belt conveyor,
The friction body is mainly blended with natural rubber, butadiene rubber, styrene-butadiene rubber, aluminum or butadiene rubber, and styrene-butadiene rubber, the blending ratio of natural rubber in these is 50 to 90% by weight, and the rubber hardness is JIS.
- A driving device for a belt conveyor, characterized in that it is constructed of a material having an Hs hardness of 50 to 70 degrees in 6301. 2. In claim 1, the friction body has a rubber hardness of 55 to 6 in Hs hardness according to JIS-6301.
5 degrees, and a blending ratio of the natural rubber is 60 to 80% by weight.