JP2008195463A - Belt meandering preventing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt driving device having a control means of simple structure capable of correcting meandering of a belt with a simple method. <P>SOLUTION: This belt driving device comprises a belt edge position detecting means 21 for detecting the quantity of meandering of a turning endless belt 1, and settles the quantity of meandering of the turning endless belt 11 between two standard positions preset by the belt edge position detecting means 21. This means has a belt meandering preventing method for tilting a driving roller 4 and a driven roller 3, or the driving roller 4 or the driven roller 3, in the vertical direction or in the back and forth direction by operating roller tilting means 53, 54, 63 and 64 based on a control signal generated from the two standard positions when the turning endless belt 1 exceeds a range of the preset two standard positions, and for settling meandering of the endless belt 1 within the range of the preset two standard positions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a meandering prevention method for an endless belt conveyor machine that can be applied to a belt conveyor that requires cleanliness and does not like the adhesion of bacteria and the generation of dust, such as a food / beverage container conveyor, a semiconductor assembly inspection conveyor, and the like.

Conventionally, the endless belt conveyor is used as a fixing belt, an intermediate transfer belt, a photosensitive belt, and a paper conveying belt in an image forming apparatus such as a copying machine and a printer, in addition to being used as a conveying device for various articles. Generally, the endless belt is supported by a plurality of rollers, and the endless belt is caused to travel by rotating one of the rollers. During the travel of the endless belt, a phenomenon occurs in which the belt moves in the width direction of the belt (a direction perpendicular to the travel direction of the belt), which is called meandering. The meandering phenomenon causes the position of each color image to shift when the images on the intermediate transfer belt such as yellow, magenta, cyan, and black are transferred with a printer or the like. It is not preferable. Similarly, in foods, liquid crystal glass substrates, electronic parts, and conveyor belt conveyors for semiconductor assembly inspection, the meandering of the belt causes a shift in the work position between processes, which prevents accurate work in the next process.

As a method for correcting the meandering of the belt, several techniques have been proposed so far. The elemental technology of these techniques is a technique for detecting the meandering of the belt, receiving the meandering amount as a control signal, and operating the support roller to correct the meandering of the belt.

  As a method for detecting the meandering of the belt, there are a method for detecting the position of the belt end by contacting a side roller and a flange roller to the end of the belt, and a non-contact detection method using an ultrasonic sensor, a magnetic sensor and an optical sensor. is there.

  As a control method, there are a digital type that emits a signal when the end of the belt reaches a predetermined position and an analog type that linearly detects an electric signal of a meandering amount. To operate the support roller with the control signal A pulse motor, a servo motor, a cam or the like is used.

Also, as a method of correcting the meandering of the belt, a method of adjusting the tension in the width direction of the belt is generally used. A taper roller, a crown roller having a reduced diameter at both ends, horizontal or up and down are used. For example, a roller that swings or tilts may be used.

As another method, to prevent meandering of a conveyor machine using an endless belt, one to several ribs are arranged as a meandering preventing member such as rubber for restricting movement in the belt width direction on the central rear surface in the belt width direction. There is also a proposal of a method for eliminating the meandering of the belt by causing the endless belt to run along a guide that is fitted with a groove corresponding to the driving roller and the driven roller.

In addition, an automatic alignment roller has been proposed in which a flexible material is provided for connecting the shaft and the drum.

JP 06-074306 JP 09-060693 JP 09-012173 JP2000-159374 JP2002-002934 JP2004-353688

  The roller inclination method generally used as a method for correcting the meandering of the belt is based on the phenomenon that “the belt moves in the direction of decreasing the tension”, and the driven roller is parallel to the belt traveling direction. To tilt the belt (the study of the Japan Society of Mechanical Engineers (C) Vol. 66, No. 647 (2000-7) "Study on belt skew"), or to tilt the driven roller up and down with respect to the direction of belt travel ([03-1] JSME 2003 Annual Conference Proceedings (4) p-235 "Study on Belt Skew") is known.

That is, in the driven roller horizontal tilting system, the driven pulley tilts the meandering side horizontally rearward so as to increase the belt tension on the meandering side of the belt. In the case of the driven roller up-and-down tilting system, the driven roller may be tilted upward on the side where the belt meanders.

Also, as the simplest control method for correcting meandering from a signal that detects the position of the end of the meandering belt, a motor or fluid pressure cylinder is used with a constant force while the belt is removed from the reference position. There is ON-OFF control that keeps the roller tilting.

However, in this belt meandering correction control method, when the straightness of the belt end surface is poor, the belt position is corrected by tilting the roller at the position detected by the line sensor, and the belt position is corrected to the normal position. Becomes a signal that the belt is still out of the proper position, and continues to tilt the roller more than necessary, resulting in excessive movement of the belt, resulting in deviating from the proper range in the reverse direction. That is, the two reference line ranges are reciprocated greatly.

In order to eliminate the reciprocating motion that deviates from the left and right of this reference range, the tilting power may be weakened. However, when the belt runs with large frictional fluctuations due to unbalanced load, the object being caught between the roller and the belt, or damage to the belt edge, the belt cannot be returned to its original position with this weak tilting force. The belt travels to the abnormality detection line provided in, and the belt travel stops.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a belt drive device characterized by having a control means for solving the above-mentioned problems with a simple structure and control method.

In order to solve the above-mentioned problems, a first aspect of the present invention provides a plurality of rollers comprising a drive roller and a driven roller, a motor for driving the drive roller, and the plurality of rollers. In a belt driving device having an endless belt stretched around a belt and driving the endless belt by driving a driving roller with a motor, the driving roller or the driven roller or the driving roller and the driven roller are flat in the belt traveling direction. A line sensor that can detect the position of the endless belt in the width direction is provided, and each line sensor has a range of two predetermined reference positions corresponding to the width direction of the belt. When the end of the endless belt comes off, a control signal is generated, and based on the signal, once every fixed waiting time (T), for a certain command time (t), the driving roller or the driven roller or The drive roller and the driven roller are tilted in the front-rear direction with respect to the belt traveling direction plane.

Next, a plurality of rollers comprising a drive roller and a driven roller, a motor for driving the drive roller, and an endless belt stretched between the plurality of rollers are provided, and the motor is driven by the motor. -In a belt driving device for driving an endless belt by driving a roller, the driving roller or the driven roller or the driving roller and the driven roller are provided with means for tilting the belt in the vertical direction with respect to the belt traveling direction plane, Two line sensors that can detect the position of the belt are provided.Each line sensor generates a control signal when the end of the endless belt deviates from two predetermined reference position ranges corresponding to the width direction of the belt. Based on the belt traveling direction plane, the driving roller or the driven roller or the driving roller and the driven roller are once per fixed waiting time (T) based on a predetermined command time (t). It is characterized by tilting up and down.

A third aspect of the invention is characterized in that in the belt driving device of the first and second aspects, the roller tilting means is a fluid pressure cylinder using compressed air or hydraulic pressure.

According to a fourth aspect of the present invention, in the belt driving apparatus according to the first or second aspect, the roller tilting means is a DC motor.

In the present invention, even when the belt end face is not straight, or when the belt travels, there is a large frictional fluctuation due to an unbalanced load, the object being caught between the pulley and the belt, damage to the belt edge, etc. The belt position is easily and reliably secured within the two reference line ranges by the weak pulley tilting force. Also, a meandering prevention member such as rubber, an abutment guide for pressing the belt edge, and automatic adjustment with both ends of the roller. Since no lead mechanism is used, there is no risk of generation of germs, dust, etc., and there is no risk of damage even if it is operated for a long time. It is possible to provide a belt driving device having a method for reliably preventing meandering of a belt including a metal which is optimal for use.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of a belt driving device according to the present invention. In the following description, the right side or the left side is displayed along the traveling direction of the upper surface of the belt 1. That is, since the upper surface of the belt 1 moves from left to right in the plan view of FIG. 1, the upper side of the plan view of FIG. 1 is the left side and the lower side is the right side. The light-emitting element 211 and the light-receiving element 212 (FIG. 2) of the belt edge position detection line sensor 21 are arranged symmetrically vertically with the endless belt 1 in between, and a pair of endless belt conveyor frames are provided near the driven roller 3. 7 is provided. As shown in FIG. 2, the line sensor-21 sets two reference positions, a reference line 1 and a reference line 2, within a range of 0 to 10 mm in a direction perpendicular to the traveling direction of the belt, and the light emitting and receiving signals are controlled. When the endless belt edge deviates from the range of these two reference positions, a control signal is always generated.

Consider a case in which the drive roller side or the driven roller side of the endless belt 1 is shifted to the right side with respect to the traveling direction. Since the end of the belt 1 exceeds the reference line 1 of the two reference positions of the line sensor 21, a control signal from the right is generated. This is because the endless belt 1 is shifted to the right because the right side tension of the driven roller 3 is weak. Therefore, the right side of the driven roller 3 may be horizontally tilted rearward in the belt traveling direction in the direction of increasing tension.

The air cylinder 53 fixed to the holding bracket 35 and directly connected to the driven roller shaft right 31 is fixed to the holding bracket 36 by an increased constant pressure determined by the electropneumatic regulator 63 and directly connected to the driven roller shaft left 32. The air cylinder 54 and the electro-pneumatic regulator 64 have a constant decrease pressure, and once every constant waiting time (T), the right side of the driven roller 3 is increased in the direction of increasing tension for a certain command time (t). The endless belt 1 is tilted horizontally in the direction so as to approach the left side opposite to the meandering direction.

On the contrary, when the endless belt 1 is shifted to the left side with respect to the traveling direction, the air cylinder is fixed to the holding bracket 35 and directly connected to the driven roller shaft right 31 based on the control signal on the left beyond the reference line 2. 53, the electropneumatic regulator 63 is actuated, and it is fixed to the holding bracket 36 by a predetermined reduced constant pressure, and is directly fixed to the left side 32 of the driven roller shaft 32, and the increased constant pressure determined by the electropneumatic regulator 64. As a result, the driven roller 3 is tilted horizontally at a constant command time (t) once every fixed waiting time (T), and the right side of the driven roller 3 is horizontally tilted in the direction of decreasing tension and the left is increased in the direction of increasing tension. Correct it so that it is closer to the right side.

By the above operation, the belt conveyor rotates without the edge of the endless belt 1 deviating from the range of two predetermined reference positions. The two reference positions can be freely changed according to different meandering amounts depending on the length, width, thickness, etc. of the endless belt of the endless belt conveyor.

Next, a description will be given of issuing a tilt command once every fixed waiting time (T) for a fixed command time (t) with reference to FIG. The line sensor outputs a Hi signal when the edge of the belt 1 crosses the reference line 1 defined for the line sensor to the right. However, since the edge of the belt 1 is not straight, the output of the line sensor repeats ON / OFF of the Hi signal. Based on the Hi signal that appears at the beginning of this ON-OFF repetition, the air cylinder or DC motor of the roller tilting means is commanded for a certain time (t) to tilt the roller so that the belt 1 moves in the opposite direction. .
Eventually, when the belt 1 crosses another reference line 2, the line sensor outputs a Hi signal of the left control signal, but the tilting operation command in the opposite direction is between the first tilting operation command and the fixed waiting time (T). The roller tilt command for moving the belt 1 in the opposite direction is issued for (t) seconds ”when this fixed time (T) has passed and the left Hi signal has been output. By repeating this, the belt can be rotated so that the meandering is within a certain range even if there is a large frictional fluctuation due to a load fluctuation or the like.

As an example, when running with a belt width of 300 mm, a belt thickness of 0.2 mm, a conveyor shaft distance of 9 m, and a belt speed of 500 mm / sec, the fixed waiting time was 60 seconds, the operation command time was 0.3 seconds, and the meandering was 2 mm or less. .

There are usually two types of belt meandering. This will be described with reference to FIG. One is that when the belt on the driven roller 3 side moves to the right, the belt on the driving roller 4 side moves to the left, and on the contrary, when the belt on the driven roller 3 side moves to the left, the driving roller. The belt on the side of the roller 4 is on the right, so-called “shaking meandering”, and in the other one, the direction of the meandering of the belt on the driven roller 3 side and the belt on the driving roller 4 side is the same. In other words, when the belt on the driven roller 3 side moves to the right, the belt on the driving roller 4 side also moves to the right, and conversely, if the belt on the driven roller 3 side moves to the left, the belt on the driving roller 4 side. The so-called “parallel meandering” where the belt also moves to the left.

Specific examples of the meandering that occur are shown in Table 1.

なお、「右」は、ベルトの端部があらかじめ定めた二つの基準線１の右方に越えた場合、
「左」は、ベルトの端部があらかじめ定めた二つの基準線２の左方に越えた場合、「中」は、ベルトの端部があらかじめ定めた二つの基準線の中間にあることを示す。
ここで例５は、蛇行がない状態であり、例１、例９は、「平行蛇行」、例3,例7は「たすき掛け蛇行」であり、例2,例4,例6,例８は「平行蛇行」のままか「たすき掛け蛇行」になるかの中間状態である。

“Right” means that the end of the belt crosses to the right of two predetermined reference lines 1.
“Left” indicates that the end of the belt crosses to the left of two predetermined reference lines 2, and “Middle” indicates that the end of the belt is in the middle of the two predetermined reference lines .
Here, Example 5 is a state without meandering, Example 1 and Example 9 are “parallel meandering”, Example 3 and Example 7 are “shaking meandering”, Example 2, Example 4, Example 6, Example 8 Is an intermediate state between “parallel meandering” and “tucking meandering”.

The method described in claim 2 is particularly effective for so-called “tackling meandering”. In FIG. 4, the endless belt 1 is shifted to the right on the driven roller 3 side, to the right of the reference line range of the line sensor 21, exceeds the reference line 1, and the endless belt 1 is shifted to the left on the drive roller 4 side. A case where the reference line 2 is crossed to the left on the left side of FIG. The air cylinders 51 and 52 are operated via the compressor 60, the distributor 68, and the regulators 61 and 62 under the control of a controller (not shown) by a signal generated when the belt edge deviates from the reference position range. The right side of the driven roller 3 is tilted upward and the left side of the drive roller 4 is tilted upward once every certain waiting time (T) for a certain command time (t) to correct the “snake meander”. is there

That is, it is fixed to the driven roller holding bracket 35 and fixed to the driven roller holding bracket 36 by an increased constant pressure determined by the air cylinder 51 and the electropneumatic regulator 61 directly connected to the driven roller shaft 31. The endless belt tilts the right side of the driven roller 3 upward and the left side downward for a predetermined command time (t) by the air cylinder 52 directly connected to the driven roller shaft 32 and the reduced constant pressure determined by the electropneumatic regulator 62. 1 is moved to the left side on the driven roller side.

On the other hand, the air cylinder 55 fixed to the conveyor frame right 72 and the decrease determined by the electropneumatic regulator 65 and the increase determined by the air cylinder 56 and electropneumatic regulator 66 fixed to the conveyor frame left 71 The drive roller holding brackets 45, 46 are moved up and down by a constant pressure once every fixed waiting time (T) for a fixed command time (t), thereby tilting the right side of the drive roller 4 downward and the left side upward. The endless belt 1 is moved to the right side on the drive roller side.

FIG. 5 is a situation diagram of the belt meandering correction of the brush meandering, and shows the tilted state of the driven roller and the driving roller as seen from the left of FIG. 4 in the case of the above example. Since the upper side of the pulley is the belt tension side, the driven roller is tilted to the right and the drive roller is tilted to the left, so that the tension on the left side of the belt is reduced on the driven roller side. On the la side, the tension on the right side of the belt acts to decrease. That is, the belt 1 moves to the left on the driven roller side, and the belt 1 moves to the right on the drive roller side, and the meandering is corrected.

In the meandering correction of the present invention, it is only necessary to operate the roller for a certain command time within a certain waiting period. Therefore, the control of the air cylinder is simple only by changing the pressure command. Even when the belt is controlled at 1,000N on one side including the initial belt tension and tilting force, a small air cylinder of □ 60mm and 140mm in length is sufficient.

Next, an embodiment of the invention using the DC motor of claim 4 as the roller tilting means of claim 2 will be described with reference to FIG. The operating principle is

The tilting means is installed only on one side as described in the embodiment, and instead of the air cylinders 51, 52, 55, 56 shown in FIG. 4, the driven roller holding bracket right 35 is provided on the driven roller side. The shaft 83 of the DC motor 81 fixed to the driven roller shaft 31 and the shaft of the DC motor 82 fixed to the conveyor frame right 72 on the drive roller side are screwed into the drive roller holding bracket right 45 to be driven roller 3, The drive roller 4 is tilted up and down.

Next, FIG. 7 is an effective measure for a small conveyor even with a simple apparatus. The line sensor 21 is installed only on the driven roller 3 side, and the driven roller 3 is tilted in the front-rear direction horizontally with respect to the running direction of the belt 1 by the DC motor 81 based on the control signal. To prevent meandering.

Note that not only a high-function motor such as a servo motor and a step motor is not required, but also a control mechanism that is smaller and less expensive than a servo motor and a step motor can be provided as described below.

As an example, when running at a belt speed of 330 mm / sec with a belt width of 300 mm, a belt thickness of 0.2 mm, and a conveyor speed of 2 m, the fixed waiting time was 60 seconds, the operation command time was 0.3 seconds, and the meandering was 1 mm or less. .

The roller is provided with a crown in order to improve the coupling between the belt and the roller and to add a meandering control capability by the roller.
In addition, although the driven roller and the driving roller are tilted by two line sensors in claim 2, are the “parallel meandering” of Example 2, Example 4, Example 6 and Example 8 described in (0029)? An example is also demonstrated in which it is effective for preventing meandering by tilting only the driven roll with a single line sensor, compared to the case of an intermediate state of “tucking meandering”.

FIG. 1 is a plan view of an endless belt drive device having a meandering prevention mechanism that horizontally tilts a driven roller to which the present invention is applied, using an air cylinder that uses compressed air as a roller tilting means, and FIG. (B) in Figure (1) is a front view, (C) in Figure (1) is a side view Schematic diagram showing the specific configuration of the line sensor The figure which shows the relationship between the control signal of roller tilt control, fixed waiting time, and roller tilt command time FIG. 4 (A) is a plan view of FIG. 4 (A) and FIG. 4 (A). FIG. B) is a front view and FIG. 4C is a side view. Situation of vertical tilt of driven roller and drive roller FIG. 6A is a plan view of an endless belt driving device having a meandering prevention mechanism for tilting a driven roller and a tilted roller to which the present invention is applied, and FIG. 6A is a plan view of FIG. B) is a front view, and (C) in FIG. 6 is a side view. FIG. 7A is a plan view, FIG. 7B is a front view, and FIG. 7C is a side view.

Explanation of symbols

1 ... Endless belt,
21, 22 ... line sensors,
211, 221... Light emitting element,
212, 222... Light receiving elements,
3 ... driven roller,
31, 32 ... driven roller shaft center,
35, 36 ... driven roller holding bracket,
4 ... Driving roller,
45, 46 ... drive roller holding bracket,
51, 52, 53, 54, 55, 56 ... fluid pressure cylinders,
60 ... Compressor,
61, 62, 63, 6465, 66 ... electro-pneumatic oil regulator,
68... Distributor
7 ... conveyor frame,
71 ... Conveyor frame left,
72 ... Conveyor frame right,
81, 82 ... DC motor,
83, 84 ... DC motor shaft end

Claims (4)

A plurality of rollers comprising a driving roller and a driven roller, a motor for driving the driving roller, and an endless belt stretched between the plurality of rollers, and the driving roller driven by the motor In the belt driving device for driving the endless belt by driving the roller, the driving roller or the driven roller or the driving roller and the driven roller are provided with means for tilting the belt in the front-rear direction with respect to the belt traveling direction plane. One line sensor that can detect the position is provided, and when the end of the endless belt is out of the range of two predetermined reference positions corresponding to the width direction of the belt in the line sensor, a control signal is generated and based on that signal Drive roller or driven roller or drive roller and driven roller forward and backward with respect to the belt traveling direction plane once every fixed waiting time A belt drive device having a belt meandering prevention method characterized by tilting in a direction. A plurality of rollers comprising a driving roller and a driven roller, a motor for driving the driving roller, and an endless belt stretched between the plurality of rollers, and the driving roller driven by the motor In the belt driving device for driving the endless belt by driving the roller, the driving roller or the driven roller or the driving roller and the driven roller are provided with a means for tilting the belt in the vertical direction with respect to the belt traveling direction plane. Two line sensors that can detect the position are provided, and each line sensor generates a control signal when the end of the endless belt deviates from the range of two predetermined reference positions corresponding to the width direction of the belt. The drive roller or driven roller or the drive roller and the driven roller are moved up and down with respect to the belt traveling direction plane once every fixed waiting time. A belt drive device having a belt meandering prevention method characterized by tilting in a direction. 3. The belt driving device according to claim 1, wherein the roller tilting means is a fluid pressure cylinder using compressed air or hydraulic pressure. 3. A belt driving device having a belt meandering prevention method according to claim 1, wherein said roller tilting means is a DC motor.

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