JP2012097820A - Roll rotationally driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an angle transmission error caused by a strain wave gear speed reducer.SOLUTION: The output sides of first and second strain wave gear speed reducers connected to individual drive motors are attached to the ends of roll shafts in both ends of a blanket roll and, when the blanket roll is rotated in one direction, the rotational directions of outputs when viewed from the outputs of the respective harmonic speed reducers are relatively reversed. When an angle transmission errors are measured for the respective strain wave gear speed reducers, the waveforms of the respective angle transmission errors are almost reversed in the rotational angle direction of the blanket roll as indicated by a line A and a line B, so that the phases of the respective strain wave gear speed reducers are shifted in such a way that the maximum value 12a and the minimum value 12b of the angle transmission error of one strain wave gear speed reducer overlap the minimum value 13a and the maximum value 13a of the angle transmission error of the other strain wave gear speed reducer. By canceling the angle transmission angle errors of the respective strain wave gear speed reducers each other, fluctuation in angle transmission errors with respect to the blanket roll is reduced.

Description

  The present invention relates to a roll rotation driving device for rotationally driving a roll that requires positioning (rotation angle) control, such as a blanket roll of an offset printing apparatus.

  A wave gear reducer, one of the reducers, is composed of a wave generator attached to the input shaft, a flex spline attached to the output shaft, and a circular spline fixed to the casing. Since it has features such as high rotation accuracy, high reduction ratio, high torque capacity, high efficiency, and no backlash, it is widely used for applications that require high positioning accuracy (controllability of rotation angle).

  Therefore, in the offset printing apparatus, it is conventionally considered that a drive motor such as a servo motor is attached to one end of the roll shaft of the blanket roll via a wave gear reducer as a rotation drive mechanism of the blanket roll. ing.

  By the way, in recent years, an image display element such as a liquid crystal display on a substrate using a printing technique using a conductive paste as a printing ink, for example, an intaglio offset printing technique, instead of fine processing such as etching of a metal vapor deposition film. There has been proposed a method of forming the electronic circuit by printing.

  When an electronic circuit is formed on the substrate by printing, the line width to be an electrode may be required to be as fine as, for example, about 10 μm. Higher printing accuracy is required compared to offset printing.

  In the offset printing apparatus, since the rotational accuracy of the blanket roll is directly related to the printing accuracy, in the offset printing apparatus that requires high printing accuracy as described above, it is necessary to control the rotation of the printing roll with high accuracy.

  However, the actual condition of the wave gear reducer is that, as its characteristics, a periodic angle transmission error of two cycles occurs every time the servo motor shaft connected to the input side makes one rotation.

  The angle transmission error of this wave gear reducer is usually such that characters and images are printed on paper or the like because the deflection width on the side preceding and behind the rotation direction is as small as about 0.01 to 0.02 degrees, for example. This offset printing is not a problem, but when high printing accuracy is required as in the case where an electronic circuit is formed on a substrate as described above, the angle transmission error of the wave gear reducer may be affected. Is concerned.

  As a method of correcting the angle transmission error by the wave gear reducer, there is a method of strictly measuring the angle transmission error and correcting the command value when driving the drive motor based on the measured value. Conventionally proposed (see, for example, Patent Document 1 and Patent Document 2).

  Also, the idea of driving one load by mechanically connecting two drive motors via a speed reducer or a gear has been conventionally proposed (for example, see Patent Document 3).

Japanese Patent No. 4254454 Japanese Patent No. 4052490 JP-A-4-109890

  However, as shown in Patent Document 1 and Patent Document 2 described above, in the method of correcting the angle transmission error of the wave gear reducer in a controllable manner, the inertia ratio (rotational inertia) between the printing roll and the rotor of the drive motor is obtained. Ratio) is sufficiently small, for example, 10 or less, but when a printing roll is large for large format printing, an extremely large drive motor is required to realize the desired inertia ratio. Become.

  Furthermore, when the method for correcting the angle transmission error of the wave gear reducer in a control manner is applied to an actual machine, it is essential to adjust the parameter according to the actual machine. It is the actual situation that swells.

  In addition, since there is no description regarding a wave gear reducer, what was shown by patent document 3 does not suggest the means to reduce the angle transmission error peculiar to a wave gear reducer.

  Accordingly, the present invention provides rotational driving of the drive target roll in a state where the angle transmission error of the wave gear reducer interposed between the drive motor and the roll shaft of the drive target roll is reduced without performing control correction. The present invention intends to provide a roll rotation driving device capable of performing the above.

  In order to solve the above-mentioned problem, the present invention corresponds to claim 1 and includes the output side of a wave gear reducer of the same type connected to the output side of the drive motor at both ends of the shaft of the roll to be driven. One wave gear reducer is connected based on the angle transmission error measured in advance for each of the wave gear reducers, so that the rotation directions of the outputs viewed from the output side of each wave gear reducer are opposite to each other. The one wave gear reducer and the other wave transmission gear so that the maximum value and the minimum value in one cycle of the angle transmission error overlap the minimum value and the maximum value in one cycle of the angle transmission error of the other wave gear reducer, respectively. A roll rotation drive device having a configuration in which the phase of the wave gear reducer is shifted is provided.

  In the above configuration, a mechanical lock mechanism is interposed between one shaft end of the driven roll and the output side of the corresponding wave gear reducer.

According to the roll rotation driving device of the present invention, the following excellent effects are exhibited.
(1) The rotation direction of the output when the output side of the wave gear reducer of the same type connected to the output side of the drive motor is viewed from the output side of each wave gear reducer at both ends of the shaft of the roll to be driven. Based on the angle transmission error measured in advance for each of the above-described wave gear reducers, the maximum value and the minimum value in one cycle of the angle transmission error of one wave gear reducer are Since the phase of the one wave gear reducer and the other wave gear reducer is shifted so as to overlap the minimum value and the maximum value in one cycle of the angular transmission error of the wave gear reducer, The angle transmission error that occurs when rotating the roll to be driven by each of the drive motors without the need for control correction using only a combination of the above combinations is the angle transmission error inherent to the wave gear reducer. Compared with it can be reduced.
(2) Therefore, the rotation accuracy and positioning accuracy of the drive target roll can be increased.
(3) Therefore, it is possible to improve the printing accuracy of offset printing by driving the roll rotation driving device of the present invention using the blanket roll in the offset printing device as a driving target roll. It can be advantageous when high printing accuracy is required, such as when an electronic circuit is formed on a substrate by printing.

It is a partially cut schematic front view which shows the example applied to the drive of the blanket roll of an offset printing apparatus as one Embodiment of the roll rotation drive device of this invention. FIG. 2 shows the principle of reducing the angle transmission error caused by the wave gear reducer by the apparatus of FIG. 1, wherein (a) shows the angle transmission error caused by the first wave gear reducer when the blanket roll is rotated in one direction. (B) is a diagram showing the periodic change of the angle transmission error caused by the second wave gear reducer, (c) is the angle transmission error caused by each wave gear reducer, It is a figure which shows the waveform which carried out the synthesis | combination by shifting the phase by predetermined amount.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIGS. 1 and 2 show a case where the present invention is applied to driving of a blanket roll of an offset printing apparatus, for example, as an embodiment of the roll rotation driving apparatus of the present invention.

  That is, the roll shafts 2 a and 2 b at both ends of the blanket roll 1 are rotatably supported via the individual bearings 4 at both ends of the roll holder 3 extending along the axial direction of the blanket roll 1.

  The output side 5o of the first wave gear reducer 5 is attached to the end of the roll shaft 2a on one end side (left side in FIG. 1) of the blanket roll 1, and the input side 5i of the first wave gear reducer 5 is attached. Is connected to an output shaft 7a of a first drive motor 7 such as a servomotor.

  Further, the second wave gear reducer 6 of the same type as the first wave gear reducer 5 is arranged so that the output side 6o faces the output side 5o of the first wave gear reducer 5. In this state, the output side 6o of the second wave gear reducer 6 is connected to the end of the roll shaft 2b on the other end side (right side in FIG. 1) of the blanket roll 1. An output shaft 8 a of a second drive motor 8 such as a servo motor is connected to the input side 6 i of the second wave gear reducer 6.

  As a result, when the blanket roll 1 is rotationally driven in a certain direction, for example, the direction indicated by the arrow r in FIG. 1, the rotational direction of the output viewed from the output side 5o of the first wave gear reducer 5 The rotation direction of the output viewed from the output side 6o of the second wave gear reducer 6 is relatively opposite. In FIG. 1, when the blanket roll 1 is rotated in the direction of the arrow r, the rotation direction of the output of the wave gear reducer 5 viewed from the output side 5o of the first wave gear reducer 5 is clockwise. The rotation direction of the output of the wave gear reducer 6 as viewed from the output side 6o of the second wave gear reducer 6 is counterclockwise.

  Further, when the rotational driving force output from the output sides 5o and 6o of the wave gear reducers 5 and 6 is transmitted to the roll shafts 2a and 2b of the blanket roll 1, the wave gear reducers 5 and 6 The rotation angle is fixed in a state in which the periodically changing angle transmission errors are overlapped at a predetermined phase described later.

  More specifically, one end of the power transmission shaft 9 is attached to the output side 6o of the second wave gear reducer 6, and the other end of the power transmission shaft 9 is connected to the other end of the blanket roll 1. It attaches to the end of the roll shaft 2b via a mechanism, that is, a so-called mechanical lock mechanism 10 that fastens mechanical components using frictional force generated by a wedge-shaped member (not shown). Thereby, in the state where the fastening between the roll shaft 2b on the other end side of the blanket roll 1 and the power transmission shaft 9 by the mechanical lock mechanism 10 is released, the mechanical lock mechanism 10 is attached to the roll shaft 2a on the one end side of the blanket roll 1. The phase of the angle transmission error between the first wave gear reducer 5 and the second wave gear reducer 6 attached to the power transmission shaft 9 can be easily adjusted. By fastening the roll shaft 2b on the other end side of the blanket roll 1 and the power transmission shaft 9 by the mechanical lock mechanism 10, the output sides of the wave gear reducers 5 and 6 are connected to the blanket roll 1 and its The roll shafts 2a and 2b and the power transmission shaft 9 can be fixed together. Therefore, the adjustment work for superimposing the periodically changing angle transmission errors of the wave gear reducers 5 and 6 at the predetermined phase can be easily performed.

  Reference numeral 11 denotes a ring-type rotary encoder attached to the outer periphery of one of the roll shafts 2a and 2b in order to detect the rotation of the blanket roll 1. FIG. 1 shows a state where the rotary encoder 11 is attached to the roll shaft 2b on the other end side.

  Here, the angle transmission error of the first wave gear speed reducer 5 will be described. The first wave gear speed reducer 5 has the above-described blanket roll 1 as an arrow r in FIG. When the output shaft 7a of the first drive motor 7 connected to the input side 5i is rotated once for two periods, for example, a line A in FIG. As described above, a cyclic angle transmission error of a waveform having a maximum value 12a and a minimum value 12b occurs in each cycle. In FIG. 2 (a), the vertical axis represents the angle transmission error [deg], the horizontal axis represents the rotation of the blanket roll 1 connected to the output side of the first wave gear reducer 5, and one roll axis. Direction, for example, a rotation angle [deg] based on the rotation direction when viewed from the roll shaft 2a on one end side (the same applies to FIGS. 2 (B) and (C) described later).

  On the other hand, the second wave gear reducer 6 has a characteristic as a wave gear reducer, and is connected to the input side 6i when the blanket roll 1 is rotationally driven in the direction indicated by the arrow r in FIG. A cyclic angle transmission error is generated in which the output shaft 8a of the second drive motor 8 rotates once for two cycles. At this time, the second wave gear reducer 6 The rotational direction of the output as seen from the output side 6o of the second wave gear reducer 6 when the blanket roll 1 is rotationally driven in the direction of the arrow r is the same as that of the wave gear reducer 5. Since the rotation direction of the output viewed from the output side 5o of the first wave gear reducer 5 is opposite to the rotation direction, the angle transmission error waveform of the second wave gear reducer 6 is shown in FIG. ) As indicated by line B, the first shown in FIG. Angle transmission error of a waveform of the dynamic gear reducer 5 (line A), is substantially identical waveforms to the shape obtained by inverting the rotation angle change direction of the blanket roll 1 is a horizontal axis (horizontal direction). Therefore, the angle transmission error of the second wave gear reducer 6 takes the minimum value 13a and the maximum value 13a for each period.

  The waveform of the angle transmission error of the first wave gear reducer 5 (line A in FIG. 2 (a)) and the waveform of the angle transmission error of the second wave gear reducer 6 (line of FIG. 2 (b)). As described above, B) has a shape that is substantially reversed in the rotational angle change direction (left-right direction) of the blanket roll 1 as described above, and therefore, the waveform of the angle transmission error of the first wave gear reducer 5 ( Changes in the rotation angle of the blanket roll 1 from the maximum value 12a to the minimum value 12b in each period of line A) in FIG. 2 (a) and the waveform of the angle transmission error of the second wave gear reducer 6 (FIG. 2 ( The change in the rotation angle of the blanket roll 1 from the minimum value 13a to the maximum value 13b in line B) of b) is almost the same.

  According to the tests conducted by the present inventors, it has been found that the waveform of the angle transmission error of each of the wave gear reducers 5 and 6 changes depending on the speed.

  In view of the above points, in the present invention, the rotational speed on the output side of the first wave gear reducer 5 and the second wave gear reducer 6 is used in the offset printing process. In a state set according to the set rotation speed in this case, the waveform of the angle transmission error generated in each of the wave gear reducers 5 and 6 is measured in advance, and the measured angle of the first wave gear reducer 5 is measured. The waveform of the angle transmission error of the second wave gear reducer 6 measured above (maximum value 12a and minimum value 12b in the transmission error waveform (line A in FIG. 2 (a)) (line in FIG. 2 (b)). The phases of the first and second wave gear reducers 5 and 6 are adjusted so that the minimum value 13a and the maximum value 13b in B) overlap.

  Thereby, since the blanket roll 1 has sufficient rotational rigidity and does not twist, the rotation of the drive motors 7 and 8 is transmitted to the blanket roll 1 through the wave gear reducers 5 and 6. Sometimes, the maximum value 12a of the angle transmission error of the first wave gear speed reducer 5 and the minimum value 13a of the angle transmission error of the second wave gear speed reducer 6 are always canceled and the first wave gear speed reduction. The minimum value 12b of the angle transmission error of the machine 5 and the maximum value 13b of the angle transmission error of the second wave gear reducer 6 are always offset.

  Therefore, the angle transmission error generated when the blanket roll 1 is rotated by the drive motors 7 and 8 is an angle obtained by adding the angle transmission errors of both the wave gear reducers 5 and 6 and dividing by 2, that is, As shown in FIG. 2C, the angle transmission error waveform of the first wave gear reducer 5 indicated by the line A and the angle transmission error of the second wave gear reducer 6 indicated by the line B are shown. Therefore, the absolute value of the error is reduced as compared with the angle transmission error inherent to the wave gear reducer 5 or 6.

  Note that the difference between the angle transmission error of each of the wave gear reducers 5 and 6 and the angle transmission error that occurs when the blanket roll 1 is rotated is the wave gear reducer 5 having a smaller rigidity than the blanket roll 1. And 6 are absorbed as deformations.

  As described above, according to the roll rotation driving device of the present invention, the individual wave gear speed reducers 5 and 6 are driven to rotate the blanket roll 1 in a certain direction on the roll shafts 2a and 2b at both ends of the blanket roll 1. Are attached so that the rotation direction of the output viewed from the output sides 5o and 6o is relatively opposite to each other, and based on the waveform of each angle transmission error measured in advance for the wave gear reducers 5 and 6 above. The angle transmission error of the second wave gear reducer 6 is transferred to the maximum value 12a and the minimum value 12b in one cycle of the waveform of the angle transmission error of the first wave gear reducer 5 (see line A in FIG. 2A). Without requiring a control correction only by a mechanical combination of adjusting the phase so that the minimum value 13a and the maximum value 13b in one cycle of the error waveform (see line B in FIG. 2B) overlap. Each drive above The angular transmission error occurring when rotating the blanket roll 1 by chromatography motor 7 and 8, in the harmonic gear reducer 5 and 6 can be reduced as compared with the inherent angular transmission error. In this case, as shown in FIG. 2C, the angle transmission error can be reduced to half or less.

  Therefore, the rotational accuracy and positioning accuracy of the blanket roll 1 can be increased, and the printing accuracy in the offset printing apparatus can be improved. Therefore, the electronic circuit is high on the substrate by printing. It can be made suitable for a roll rotation drive device for rotationally driving the blanket roll 1 in an offset printing apparatus that requires printing accuracy.

  It should be noted that the present invention is not limited only to the above-described embodiment, but the angular transmission errors of the first and second wave gear reducers 5 and 6 shown in FIGS. 2 (a), (b), and (c). And the combined waveform of these are examples, and the actually measured waveforms of the angular transmission errors of the first and second wave gear reducers 5 and 6 are waveforms other than those shown in the figure. Also good. Even if the waveforms are different, as described above, the waveform of the angle transmission error of the first wave gear reducer 5 and the waveform of the angle transmission error of the second wave gear reducer 5 are as follows. The shapes of the blanket rolls 1 are reversed in the direction of change in the rotation angle (left and right direction), and from the maximum value 12a to the minimum value 12b in each cycle of the angle transmission error waveform of the first wave gear reducer 5. Since the rotation angle change of the blanket roll 1 and the rotation angle change of the blanket roll 1 from the minimum value 13a to the maximum value 13b in the waveform of the angle transmission error of the second wave gear reducer 6 are substantially the same, The maximum value 12a and the minimum value 12b of the angle transmission error waveform of the first wave gear reducer 5 are set to the minimum value 13a and the maximum of the angle transmission error waveform of the second wave gear reducer 6. 13b is there is no problem in identifying the phase, such as to overlap respectively.

  In the above-described embodiment, both the angle transmission error waveforms of the first and second wave gear reducers 5 and 6 are measured in advance. The angle transmission error waveform is measured in advance for only one of them, and the waveform is inverted in the direction of change in the rotation angle of the blanket roll 1 (left-right direction). The waveform of the angle transmission error may be estimated. Even in such a configuration, the angle transmission error generated when the blanket roll 1 is rotated by the drive motors 7 and 8 is reduced as compared with the angle transmission error inherent to the wave gear reducers 5 and 6. Can do.

  In the roll rotation driving device of the present invention, any roll other than the blanket roll in the offset printing apparatus is driven as long as the driving motor is attached to the roll shaft via a wave gear reducer. It may be applied to.

  Of course, various modifications can be made without departing from the scope of the present invention.

1 Blanket roll (driven roll)
2a, 2b Roll shaft (axis)
5 First wave gear reducer (wave gear reducer)
5o Output side 6 Second wave gear reducer (wave gear reducer)
6o Output side 7 Drive motor 8 Drive motor 10 Mechanical lock mechanism 12a Maximum value 12b Minimum value 13a Minimum value 13b Maximum value

Claims (2)

  The output rotation directions of the wave gear reducers of the same type connected to the output side of the drive motor at both ends of the shaft of the roll to be driven are opposite to each other when viewed from the output side of each wave gear reducer. Based on the angle transmission error measured in advance for each of the wave gear reducers, the maximum and minimum values in one cycle of the angle transmission error of one wave gear reducer are the other wave gear reduction. Roll rotation characterized by having a configuration in which phases of the one wave gear reducer and the other wave gear reducer are shifted so as to overlap with a minimum value and a maximum value in one cycle of the angle transmission error of the machine, respectively. Drive device.   The roll rotation driving device according to claim 1, wherein a mechanical lock mechanism is interposed between one shaft end of the driven roll and the output side of the corresponding wave gear reducer.

Images