JP6179032B2 - Roller and roller curvature correcting device - Google Patents

Description

  The present invention relates to a roller that is rotationally driven around a central axis and a roller curvature correcting device.

  Conventionally, in the paper manufacturing industry, film makers, etc., long rollers that are driven to rotate around the central axis have been used. These rollers are passed in the horizontal direction, and due to their length and weight, they are bent by the order of 0.01 mm by gravity. As a result, for example, the thickness of the film or paper to be produced is uneven, and the thickness of the central portion and the end portion is different.

  A method for correcting such a curvature of the roller from the outside has been proposed. For example, in the fixing device described in Patent Document 1, a reinforcing member for correcting deformation of the fixing roller from the outside is provided, and the deformation is limited by pressing with a roller in contact with the outer periphery of the fixing roller. Further, the recording apparatus described in Patent Document 2 conveys a medium while correcting the deflection of the rotation shaft of the conveyance drive roller by abutting the actuator from the direction in which the deflection is eliminated by the expansion and contraction of the piezoelectric element.

JP 2001-296770 A JP 2007-260981 A

  However, if correction is performed by applying a force from the outside of the roller as in the above example, fine adjustment is difficult and rotation may be hindered. Moreover, there is a possibility of damaging the roller surface, and it is also assumed that a transported body such as a film or paper is damaged.

  The present invention has been made in view of such circumstances, and provides a roller and a roller bending correction device that can prevent the roller from being bent by the action of its own weight and gravity without applying force from the outside. With the goal.

  (1) In order to achieve the above object, the roller according to the present invention is a roller that is driven to rotate about a central axis, and the center of the roller main body and the center of the roller main body in the central axis direction is the center. A piezoelectric plate provided with a main surface perpendicular to the axis, divided into a sector and having a plurality of displacement areas displaced in the thickness direction; and a lead for applying a voltage to each of the displacement areas; And the piezoelectric plate corrects the curvature of the central axis of the roller body by the displacement of the displacement region. Accordingly, it is possible to prevent the roller from being bent by the action of its own weight and gravity without applying a force from the outside.

  (2) Further, in the roller of the present invention, the displacement region is characterized in that the entire region of the piezoelectric plate is divided into four equal parts in the circumferential direction. Thereby, the increment of the applied voltage is made finer, and the displacement region to which the voltage is applied can be switched smoothly.

  (3) The roller according to the present invention is characterized in that the piezoelectric plate has a fan-shaped electrode on one main surface and a ground electrode on the other main surface. Thus, the design of the electrode is easy and the piezoelectric plate can be easily manufactured.

  (4) In the roller of the present invention, the roller body is characterized in that a cylindrical portion on one end side and a cylindrical portion on the other end side of the central shaft are fixed with the piezoelectric plate interposed therebetween. Thereby, the curvature of the roller can be corrected by reflecting the displacement of the piezoelectric plate on the roller.

  (5) Further, the roller curvature correcting device of the present invention includes the above-described roller, a displacement meter for detecting the curvature of the central axis of the roller, an encoder for detecting the rotational position of the roller, and the detected roller. And an applied voltage control unit that applies a voltage to each displacement region of the piezoelectric plate so as to correct the detected curvature of the central axis in accordance with the rotation position. Thus, the detection result of the displacement meter is fed back to the piezoelectric body, and the applied voltage settles to the optimum value, so that the curvature can be stably corrected.

  (6) Further, in the roller curvature correcting device of the present invention, the roller is passed so that the central axis is horizontal, and the applied voltage control unit is displaced vertically below the detected rotational position. The thickness of the region is reduced, and the thickness of the displacement region on the vertically upper side is increased. Thereby, the curvature of the roller can be corrected in real time.

  According to the present invention, it is possible to prevent the roller from being bent by the action of its own weight and gravity without applying a force from the outside.

It is a figure which shows the structure of the roller curvature correction apparatus of this invention. It is a block diagram which shows the structure of the roller curvature correction apparatus of this invention. (A), (b) is the top view and side view which respectively show an example of a structure of a piezoelectric plate. It is a figure which shows joining to the roller main body of a piezoelectric plate. (A), (b), (c) It is a perspective view which shows the state which correct | amended the displacement sagging state, respectively, the state correct | amended so that the center may be made into the zero point, and the whole bias.

  Next, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

[First Embodiment]
(Configuration of roller curvature correction device)
FIG. 1 is a diagram illustrating a configuration of the roller curvature correcting device 100. FIG. 2 is a block diagram showing a configuration of the roller curvature correcting device 100. The roller curvature correcting device 100 includes a roller 10, a displacement meter 4, an encoder 3, and an applied voltage control unit 2.

  The roller 10 is formed in a cylindrical shape and is driven to rotate about the central axis c. An object such as a film or paper is transferred by the rotation of the roller 10. In addition, it is preferable that the roller 10 is passed so that the center axis | shaft c may become horizontal. That is, the roller curvature correcting device 100 is suitable for preventing a long roller from being bent by the action of its own weight and gravity.

  Even when the central axis c is not used horizontally, it is effective for preventing the bending of the roller 10. However, when correcting the bending due to an external force that greatly exceeds gravity, it is assumed that the load on the piezoelectric plate 1 becomes too large. It is not suitable. Details of the roller configuration will be described later.

  The displacement meter 4 is installed near the center of the roller 10 and monitors the height of the roller 10. For example, the curvature of the central axis c of the roller 10 is detected by measuring the distance to the cylindrical surface of the roller 10. By detecting the distance to the surface of the roller 10, the height (left and right, center) of the roller 10 can be detected. A distance meter can be used as the displacement meter 4.

  The encoder 3 detects the rotational position of the roller 10. Depending on the detected rotational position, it is possible to distinguish the upper side and the lower side with respect to the direction of external force (for example, gravity), and to correct the curvature by displacing each displacement region.

  The applied voltage control unit 2 calculates how much voltage is applied to which displacement region of the piezoelectric plate 1 by multiplying the signal of the encoder 3 and information by using the ideal position of the central axis c as a reference. As a result, a voltage is applied to each displacement region of the piezoelectric plate 1 so as to correct the detected curvature of the central axis in accordance with the detected rotational position of the roller 10.

  The applied voltage control unit 2 preferably reduces the thickness of the displacement region on the vertically lower side by the calculated value and increases the thickness of the displacement region on the vertically upper side at the detected rotational position. Thereby, the curvature of the roller 10 can be corrected in real time.

  The applied voltage control unit 2 preferably applies a correction voltage to the position of the roller 10. A voltage is applied to the piezoelectric plate 1 with respect to the detection value of the displacement meter 4 irrespective of the rotational speed of the roller 10. This makes it possible to prevent the rollers from bending with a simple configuration.

  The ideal position (zero point) is preferably the same height as the left and right heights of the roller 10 or the height at which the undulation of the entire roller 10 is minimized. The roller 10 whose central portion is lifted by the piezoelectric plate 1 is fed back to the applied voltage to the piezoelectric plate 1 by the displacement meter, and the applied voltage settles to the optimum value, so that the curvature can be corrected stably.

  When the object passing through the roller 10 is at a high temperature, the request for correcting the curvature of the roller 10 is further increased. Since the roller 10 is rotating, heat is evenly applied, but the eccentricity of the roller 10 also occurs due to a subtle difference in thermal expansion of the roller 10. The eccentricity of the rollers 10 vibrates during rotation, not only reducing the life of the apparatus and the rollers 10, but also causing the rollers 10 to be destroyed in the worst case. Therefore, it is necessary to control the eccentricity below a certain amount. is there.

(Roller configuration)
The roller 10 includes a roller body 11, the piezoelectric plate 1, and leads 15. The roller body 11 is formed in a cylindrical shape. The roller body 11 is configured by fixing a cylindrical portion 11a on one end side and a cylindrical portion 11b on the other end side of a central axis c with a piezoelectric plate interposed therebetween. Thereby, the curvature of the roller 10 can be corrected by reflecting the displacement of the piezoelectric plate 1 on the roller 10.

  The roller body 11 is made by welding core rods to the left and right of a hollow core metal made of iron or SUS. The surface of the roller body 11 is preferably provided with a lining coated with a material such as urethane. Since the curvature due to its own weight is conspicuous in the long roller 10, the present invention is particularly effective for a long and thin roller (for example, a length of more than 5 m and a diameter of 20 cm or less). Further, even a roller having a length exceeding 10 m and a weight of several hundred kg can be applied.

  The piezoelectric plate 1 is configured by providing electrodes such as Ag on both principal surfaces of a piezoelectric layer formed of a piezoelectric material such as PZT. The piezoelectric plate 1 is formed as a circular plate, and is provided so that the main surface is perpendicular to the central axis c at the center of the roller body 11 in the direction of the central axis c. In addition, the piezoelectric plate 1 is divided into sectors and has a plurality of displacement regions that are displaced in the thickness direction. In order to form the above-described displacement region, the piezoelectric plate 1 has a fan-shaped electrode on one main surface, and the entire GND electrode on the other main surface. The piezoelectric plate 1 is preferably a disc, but may be a polygon. Details of the configuration of the piezoelectric plate 1 will be described later.

  The lead 15 electrically connects the applied voltage control unit 2 and the piezoelectric plate 1 and is provided to apply a voltage for each displacement region. When a four-phase voltage is applied from the outside, a brush can be provided on the side of the shaft of the roller 10 and applied to the divided electrodes via the same principle as that of a motor brush. The GND electrode can be connected via a bearing.

  In the above method, for example, when the voltage application is finely controlled as in the 8-phase, the number of brushes increases. In this case, the applied voltage control unit 2 is provided in the shaft and in the roller, and the applied voltage and encoder from the outside are provided. A signal and a displacement signal may be supplied. In that case, it is only necessary to provide three paths with the common GND.

(Configuration of piezoelectric plate)
3A and 3B are a plan view and a side view showing an example of the configuration of the piezoelectric plate 1, respectively. In the example shown in FIG. 3, the displacement region is divided into four areas A, B, C, and D by dividing the piezoelectric plate 1 with electrodes on one main surface. In contrast to the electrodes A, B, C, and D on one main surface, the electrode E on the other main surface is provided on the entire surface as a GND electrode. About said displacement area | region, it shall rotate 1 turn in order of A->B->C-> D with respect to the rotation direction.

  At the moment when the roller 10 is rotating, A is positioned vertically above and C is positioned vertically below. At that time, the roller 10 is slightly bent by its own weight from the A side to the C side. When the rotation progresses and B comes vertically upward, D comes vertically downward and slightly turns to the D side by its own weight. In this way, the bending direction changes sequentially due to its own weight. Therefore, the electrode to which a voltage is applied to correct this also changes.

  The piezoelectric plate 1 of FIG. 3 is polarized in the same direction for each of the four displacement regions. Here, when A is on the vertically upper side, this is detected by the encoder, and the correction circuit applies a voltage in the direction of stretching to A, and about half of that is applied to B and D before and after A. Apply voltage. The application of this voltage is sequentially switched to → B → C → D in accordance with the position of the roller. Further, smoother switching can be achieved by finely dividing the number of divisions and voltage.

  The piezoelectric plate 1 corrects the curvature of the central axis c of the roller body 11 by the displacement of the displacement region. The displacement region is, for example, a region in which the entire piezoelectric plate is divided into four equal parts in the circumferential direction. Thereby, the increment of the applied voltage is made finer, and the displacement region to which the voltage is applied can be switched smoothly. And it can prevent that a roller curves by the effect | action of self-weight and gravity, etc., without applying force from the outside.

  Note that the displacement region is preferably divided into four equal parts, but is not necessarily limited thereto, and may be divided into three equal parts and five equal parts. For example, even in the case of a displacement region of three equal parts, it is considered that the force naturally balances at the position of the divisional break and the displacement becomes smooth. In that case, an upward force can always be generated with the three force vectors.

(Roller production method)
A method for manufacturing the roller 10 will be described. FIG. 4 is a diagram showing the bonding of the piezoelectric plate 1 to the roller body 11. The method shown in FIG. 4 is an example of a method for fixing the piezoelectric plate 1 to the roller 10.

  The cylindrical portions 11a and 11b constituting the one end side and the other end side along the central axis c of the roller 10 are processed to have flat end surfaces. Then, the two cylindrical portions 11a and 11b are fixed by sandwiching the piezoelectric plate 1 between them and screwing screws into the plurality of screw holes 21 on the outer peripheral side of the piezoelectric plate. The screw can be inserted and tightened from an insertion hole formed in either one of the cylindrical portions 11a and 11b. However, if the fixing is too strong, the roller 10 will not move, so it is preferable to manage the pressing pressure by inserting a spring washer.

  Further, if the roller 10 is light or light torque, the center portion may be bonded with one screw, or the piezoelectric plate 1 and the cylindrical portions 11a and 11b may be bonded with an adhesive without attaching a screw. May be. The position of the piezoelectric plate 1 is preferably the center of the roller 10 in the longitudinal direction. When correcting distortion due to its own weight, it is most efficient to correct at the center.

(Control method of applied voltage)
FIGS. 5A, 5B and 5C are perspective views showing a displacement sag state, a state where the center is corrected to the zero point, and a state where the entire bias is corrected to be minimum.

  As shown in FIG. 5B, the amount of sag of the roller 10 as shown in FIG. 5A is measured in advance, and the position when the amount of sag is corrected is set as a zero point and corrected. This makes it possible to correct the center portion with zero displacement. Further, by measuring the displacements at both ends in the direction of the central axis c in addition to the displacement at the center of the roller and controlling so as to minimize the overall bias, the correction as shown in FIG.

DESCRIPTION OF SYMBOLS 1 Piezoelectric plate 2 Applied voltage control part 3 Encoder 4 Displacement meter 10 Roller 11 Roller main body 11a, 11b Cylindrical part 15 Lead 21 Screw hole 100 Roller curvature correction apparatus c Center axis A, B, C, D Displacement area A, B, C , D Electrode E GND electrode (corresponding to the displacement region)

Claims (6)

A roller driven to rotate about a central axis,
A cylindrical roller body;
A piezoelectric plate having a plurality of displacement regions that are provided in a center in the central axis direction of the roller body so that a main surface is perpendicular to the central axis, is sectioned in a sector shape, and is displaced in a thickness direction;
A lead for applying a voltage for each displacement region,
The roller, wherein the piezoelectric plate corrects the curvature of the central axis of the roller body by the displacement of the displacement region.   The roller according to claim 1, wherein the displacement region is a region obtained by dividing the entire region of the piezoelectric plate into four equal parts in the circumferential direction.   3. The roller according to claim 1, wherein the piezoelectric plate has a fan-shaped electrode on one main surface and a ground electrode on the entire main surface.   4. The roller body according to claim 1, wherein a cylindrical portion on one end side and a cylindrical portion on the other end side of the central shaft are fixed to each other with the piezoelectric plate interposed therebetween. Roller. A roller according to any one of claims 1 to 4,
A displacement meter for detecting the curvature of the central axis of the roller;
An encoder for detecting the rotational position of the roller;
An applied voltage control unit that applies a voltage to each displacement region of the piezoelectric plate so as to correct the detected curvature of the central axis in accordance with the detected rotational position of the roller. Roller curvature correction device. The roller is passed so that the central axis is horizontal,
6. The applied voltage control unit according to claim 5, wherein, at the detected rotational position, the thickness of the displacement region on the vertically lower side is reduced and the thickness of the displacement region on the vertically upper side is increased. Roller curvature correction device.

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