JP4413498B2 - Friction drive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a friction drive device that moves a moving body forward and backward by rotating a drive shaft, and in particular, movement in an optical disc master exposure apparatus that includes a slide table that is a moving body that accurately exposes a track pitch to an optical disc master. The present invention relates to a friction drive device applied to a body drive unit.
[0002]
[Prior art]
Conventionally, many inventions for realizing high-precision feeding have been made in slide table devices for optical disc master exposure (Patent Documents 1 to 3).
[0003]
2. Description of the Related Art In slide table devices for optical disk master exposure, an air slide type slide table device in which a slide table is provided so as to be movable back and forth via a hydrostatic bearing is used. For driving the slide table, a voice coil type linear motor is generally used, and a closed loop control system using an interference laser length measuring device or a linear scale as a position detector is adopted. In addition, since a semiconductor inspection apparatus or the like that requires a stationary state requires rigidity in the feed direction, a ball screw or the like is used to drive the slide table.
[0004]
With the recent increase in the density of optical discs, exposure methods using electron beams from conventional laser beams have emerged in order to realize higher resolution exposure. Accurate feeding is becoming necessary.
[0005]
The twist roller system of the friction drive mechanism makes it possible to realize a small lead that cannot be obtained by other mechanisms by minimizing the crossing angle between the drive shaft and the driven shaft, and high positioning resolution is expected. Therefore, various mechanisms have been proposed in the patent literature and non-patent literature as next-generation feeding mechanisms.
[0006]
For example, the invention described in Patent Document 4 includes a barrel and a barrel shape that includes a shaft and an advancing / retreating part that penetrates the shaft so as to be relatively rotatable and movable back and forth, and that is in rolling contact with the shaft as advancing / retreating part body. A plurality of rollers are arranged in the circumferential direction, and these rollers are rotatably supported between the advancing / retreating part main body and the preloading plate via balls on both end faces. At least one of at least one of the preload plate and the roller end surface is configured to support the ball with a conical surface-shaped ball support recess into which the ball is rotatably fitted. In addition, by providing an elastic body that urges the preload plate toward the roller and urges it in the circumferential direction, it has high resistance to disturbance, uniform speed, stable feed, and the drive source is stationary when stopped The apparatus can improve the performance.
[0007]
The invention described in Patent Document 5 includes a frictional advance / retreat drive device that statically supports a slide body serving as a table with a hydrostatic linear motion bearing with respect to a base and slidably drives the slide relative to the base. The frictional advance / retreat drive device includes a main shaft that is rotationally driven, and a plurality of rollers that are provided around the main shaft and contact each other with an inclination angle, and preload means that applies preload to the main shaft is provided to the roller. Thus, the slide table device for the optical disc mastering device can perform stable feeding without causing unevenness of the velocity, is resistant to disturbances, improves resolution, and enables high-density writing.
[0008]
The invention described in Patent Document 6 includes a main shaft, a roller that is in rolling contact with the outer periphery of the main shaft at an inclination angle, and a slide body that moves together with the roller as the main shaft rotates. The speed reducer is transmitted to the main shaft, and the speed reducer is configured to decelerate by the rotation transmission from the first and second drive side shafts to the friction wheel to reduce the influence of the rotation unevenness of the rotational drive source. The phase shift in the rotation transmission system is reduced, and precise positioning is possible.
[0009]
According to the technique described in Non-Patent Document 1, a table guided by an aerostatic bearing is slightly intersected with a drive shaft supported at both ends by an aerostatic bearing and the axis of the drive shaft. A positioning resolution of 2 nm is realized in a lead of about 70 μm by a mechanism comprising a driven shaft installed with a corner and a roller supported by a plurality of ball bearings around the driven shaft.
[0010]
[Patent Document 1]
JP 2002-25128 A
[Patent Document 2]
JP 2002-92973 A
[Patent Document 3]
JP 2002-279700 A
[Patent Document 4]
JP-A-8-184360
[Patent Document 5]
Japanese Patent Laid-Open No. 11-195247
[Patent Document 6]
JP-A-11-195248
[Non-Patent Document 1]
Mizumoto et al., "Development of ultra-precise positioning system using twist roller friction drive", Proc.
[0011]
[Problems to be solved by the invention]
By the way, in the case of the invention described in Patent Document 4, since the rollers are arranged at an equal angle (120 degrees) with respect to the drive shaft center, they are respectively formed on the fixed plate and the opposing plate that support the roller end surfaces. Due to the mechanical position error of the conical ball support recess, the angle between each roller axis and the drive shaft tends to vary.
[0012]
This is not a problem when the angle formed by the roller shaft core and the drive shaft center is large, in other words, when the lead (distance traveled in the axial direction) is relatively large (for example, several mm). When the angle between the drive shaft and the driven shaft is small, in other words, when the lead is made small (for example, several hundred μm), if there is variation in the angle formed between each roller shaft core and the drive shaft, Slip due to read error occurs between the two.
[0013]
Also, because the roller rolling trajectory on the outer periphery of the drive shaft is different for each roller at the contact point between the drive shaft and the roller, there is a slight bend due to the processing error of the drive shaft, or the shaft center of the drive shaft and the moving parts If there is an error between the guide mechanisms due to an assembly error or the like, a large slip occurs if the lead L is large. Since this is a disturbance of closed loop control, it is not preferable in terms of control, and when applied to optical disk master exposure, the track pitch accuracy is deteriorated, which is not preferable in terms of exposure quality.
[0014]
Furthermore, in the invention described in Patent Document 4, an elastic body that biases the preloading plate toward the roller and in the circumferential direction is provided, and the adjustment of the preload amount with respect to the shaft body of the roller is performed by the advance / retreat component main body. As a position where the hole portion having the screw portion provided in the hole and the hole portion provided in the preloading plate communicate with each other, an elastic body is provided in the communication hole portion, and elasticity by tightening the thread screw of the screw portion provided in the advancing / retreating part main body Utilizes the body's compressive deformation force. In such a configuration, it is impossible to quantitatively check the current preload amount for the roller shaft body, so trial and error will be required to obtain an appropriate preload amount, and aged due to wear of the roller or shaft body. It is difficult to readjust the preload accompanying the change, there is no reproducibility of the preload amount at the time of parts replacement, and there is a problem that the assemblability is poor.
[0015]
In the invention described in Patent Document 5, preload means for applying a preload to the main shaft to the roller is provided. However, a straight line is provided between the fixed portion of the hydrostatic linear motion bearing fixed to the base and the main shaft of the friction advance / retreat drive device. There is a risk of assembly in a state where there is an error in sex. In this case, when the slide body moves in the feed direction, the straight error is absorbed between the roller having the lowest rigidity and the main shaft only by being preloaded and fixed. The preload amount with respect to changes with the movement position.
[0016]
The driving force F in the driving shaft direction acting between the driving shaft and one roller is F = μN, where μ is the dynamic friction coefficient between the outer periphery of the driving shaft and the roller, and N is the preload. Accordingly, the driving force generated on the outer periphery of each roller and the driving shaft also varies, and this also causes variation in each driving force. Therefore, there is a synergy with the variation in the angle between the axis of each roller and the driving shaft. Then, slip occurs between the drive shaft and the driven shaft roller, and this is a disturbance in the closed loop control, which is not preferable for control, and when applied to optical disc master exposure, the track pitch accuracy is deteriorated. It is not preferable in terms of exposure quality.
[0017]
In the invention described in Patent Document 6, the slide body is configured to be statically supported by a static pressure linear bearing with respect to the base, and in the technique described in Non-Patent Document 1, the slide body is guided by an air static pressure bearing. Although the table is configured to support both ends with an air hydrostatic bearing, the hydrostatic bearing which is a feeding and rotating component is very expensive, so the cost of the apparatus becomes high.
[0018]
It is an object of the present invention to provide a friction drive device that can be applied to an optical disk master exposure apparatus and the like that can realize high-precision feeding without causing the above-described conventional problems.
[0019]
[Means for Solving the Problems]
In order to achieve the object, the invention according to claim 1 is provided on each of the drive shaft and at least two driven shafts inclined at an inclination angle with respect to the drive shaft, and is in contact with the outer periphery of the drive shaft. A roller that moves along with the driven shaft and the roller by rotation of the drive shaft, a fixed plate that is fixed to the movable body, passes through the drive shaft, and is fixed to the driven shaft, and the movement And a guide mechanism for guiding the body in the axial direction of the drive shaft, wherein the driven shafts are arranged equiangularly in the circumferential direction with respect to the axis of the drive shaft, and The fixed plate is installed at an inclination angle θ, and a fixed end of two driven shafts of the at least two driven shafts on the fixed plate is connected to the drive shaft and the roller provided on the driven shaft. And the distance to the point respectively La, and Lb, the diameter of the drive shaft when is D, and configured to have a relationship of La = Lb- (π · D / 3) · θ A friction drive device, wherein one end of the driven shaft is supported by a spherical bearing, and the other end of the roller provided on the driven shaft is a fulcrum supporting a rotation support point from the outer periphery of the drive shaft to the center of the spherical bearing. As a free support by a first elastic body that presses in the separating direction and a second elastic body that presses in the tangential direction of the outer periphery of the drive shaft, the moving body is placed on the opposite side of the roller across the rotation support point First pressing means that presses the driven shaft in a direction that cancels the moment force around the rotation support point due to the pressing force of the first elastic body in a direction perpendicular to the axis of the drive shaft; A second pressing means for pressing the driven shaft in a direction that cancels out a moment force around the rotation support point caused by a pressing force of the second elastic body in a tangential direction of the outer periphery of the drive shaft; and the first pressing Pressing / releasing means, the roller in front Based on a first output means for controlling to move / fix in the axial direction of the driven shaft, an origin detection signal per rotation of the drive shaft, and an output signal of the roller movement amount detection means, the roller The angle error calculating means for calculating the tilt angle error with respect to the driven shaft in which the roller provided on the driven shaft movable in the axial direction is fixed in the axial direction, and the output signal corresponding to the calculated angle is increased or decreased from the current applied signal. Angle correction means comprising second output means for applying the corrected signal to the second pressing means. With this configuration, even if there is bending of the drive shaft due to processing, assembly error, etc., slip due to read error does not occur between the drive shaft and each driven shaft roller, Further, since it is possible to correct the variation in the crossing angle between each driven shaft and the drive shaft caused by a mechanical position error due to processing, assembly error, etc., the axis between each roller and the drive shaft is formed. The angle can be set precisely, and no slippage occurs due to lead error between the drive shaft and each driven shaft roller. Stable feed control can be realized, and feed accuracy can be improved.
[0024]
Claim 2 The invention described in claim 1 In the friction drive apparatus described above, the first output means includes a constant voltage circuit, a change-over switch that receives an output signal of the constant voltage circuit and is turned on / off by an external signal, and a deforming portion of the first pressing means. And a servo control means for performing servo control by comparing a pressing expansion / contraction setting signal, which is an output signal of the changeover switch, with a current pressing expansion / contraction amount, which is an output signal of the deformation amount measuring means. With this configuration, it is possible to perform the pressing (preload) operation on the outer periphery of the drive shaft of the roller and the angle correction operation for correcting the intersecting angle between each driven shaft and the drive shaft with high reproducibility. Furthermore, stable feed control can be realized, and feed accuracy can be improved.
[0025]
Claim 3 The invention described in claim 1 In the friction drive apparatus described above, the first output means includes a variable voltage circuit, a change-over switch to which an output signal of the variable voltage circuit is input and turned on / off by an external signal, and the first pressing plate. A deformation amount measuring means provided between a support point and the roller for detecting a deformation amount in the pressing direction of the driven shaft on an outer peripheral portion of the driven shaft, and a pressure setting signal and a deformation amount as an output signal of the changeover switch It is characterized by comprising servo control means that servo-controls by comparing the current pressing amount that is the output signal of the measuring means, and with this structure, the signal that replaces the preload amount for the drive shaft of the roller with the deformation amount of the driven shaft Since the preload servo is used, the appropriate preload condition can be instantly set, the readjustment of preload due to aging due to wear of the roller or drive shaft becomes easy, and the preload amount can be restored when replacing parts. Sex is a good, it is possible to improve the assembling property.
[0026]
Claim 4 The invention described in claim 1 In the friction drive apparatus described above, the first output means is provided between one digital / analog converter, the first pressing means, the rotation support point, and the roller, and is provided on the outer peripheral portion of the driven shaft. A deformation amount measuring means for detecting a deformation amount in the pressing direction of the driven shaft, a pressure setting signal that is an output signal of the digital / analog converter, and a current pressure amount that is an output signal of the deformation amount measuring means are compared. It is characterized by the fact that it is composed of servo control means for servo control. With this configuration, the preload servo is performed with a signal in which the preload amount for the drive shaft of the roller is replaced with the deformation amount of the driven shaft, as described above. The preload conditions can be set instantly, the preload can be readjusted with the passage of time due to wear of the roller or drive shaft, and the reproducibility of the preload when replacing parts is good, improving the assembly. Let It is possible.
[0027]
Claim 5 The invention described in claim 1 In the friction drive apparatus described above, the second output means includes a digital signal / analog converter, a deformation amount measuring means provided at a deforming portion of the pressing plate, and a pressure expansion / contraction which is an output signal of the digital signal / analog converter. It comprises a setting signal and a servo control means for performing a servo operation by comparing a current pressing expansion / contraction amount which is an output signal of the deformation amount measuring means. (Preload) operation and angle correction operation for correcting the crossing angle between each driven shaft and drive shaft can be performed with high reproducibility, so that more stable feed control can be realized and feed accuracy can be improved. it can.
[0028]
Claim 6 The invention described in claim 1 5 In the friction drive device according to any one of the above, the first guide portion provided in the direction of pressing the driven shaft in the fixed plate fixed to the moving body, and the first guide portion are fitted. A first pressing plate provided on the fixing plate, a first adjusting screw provided in a direction of pressing the driven shaft of the fixed plate, and the first pressing plate to which the first adjusting screw is screwed. A second screw provided in a direction in which the driven shaft of the fixed plate is pressed in a tangential direction of the outer periphery of the drive shaft. A guide portion, a second pressing plate provided so as to be fitted to the second guide portion, and a second pressure plate provided in a direction in which the driven shaft of the fixed plate is pressed in a tangential direction of the outer periphery of the drive shaft. And a rear end side surface of the second pressing plate. Thus, it is possible to adjust the position of the driven shaft in a direction in which the driven shaft is pressed in the tangential direction of the outer periphery of the drive shaft, and this configuration enables angle correction operation even at a large intersection angle. Stable feed control can be realized in a wide range of lead conditions, and versatility as a feed component can be enhanced.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
1 is a plan view of a friction drive apparatus for explaining Embodiment 1 of the present invention, FIG. 2 is a right side view of the friction drive apparatus of Embodiment 1, and FIG. 3 is a part of the friction drive apparatus of Embodiment 1. FIG. 4 is a perspective view for explaining a main part of the first embodiment.
[0031]
As shown in FIG. 2, a base 1 provided on an anti-vibration mechanism (not shown) composed of a pneumatic servo mounter or the like is provided with a plurality of support columns 2 that are spaced apart in the direction perpendicular to the feed direction and fixed at their lower ends. The movable body 4 is fixed to the upper end of each support column 2 via a rolling bearing (for example, a sphere, a cylindrical roller, etc.) 3 constituting a guide mechanism arranged in the feed direction. A turntable 5 is fixed to the upper part of the moving body 4, and an air spindle 6 that is statically levitated in the radial and thrust directions is fixed by compressed air supplied from the outside (not shown). An optical rotary encoder 8 composed of an A-phase and B-phase pulse whose output is divided into several thousand equal parts per revolution and a Z-phase pulse generated once per revolution is fixed via the motor 7. It is freely rotatable by an energization signal to the rotary drive motor 7 from the outside.
[0032]
The lower part of the left end portion of the moving body 4 is composed of an optical linear encoder or the like whose output is composed of A-phase and B-phase pulses having a certain resolution in the moving direction. As shown in FIG. Position detecting means 11 comprising a light receiving portion 9 for measuring a position in the direction and a scale 10 is provided, the scale 10 is fixed to the moving body 4 via a mounting plate 12, and the light receiving portion 9 is It is fixed to the base 1 via the mounting plate 13.
[0033]
In this example, the scale 10 is fixed to the moving body 4 and the light receiving unit 9 is fixed to the base 1. However, the light receiving unit 9 is fixed to the moving body 4 and the scale 10 is fixed to the base 1. May be.
[0034]
As shown in FIG. 3, a pair of opposing fixing plates 16 provided with through holes through which the drive shaft 15 passes are fixed to the lower part of the projecting portion 14 extending in the feeding direction of the moving body 4. . Three driven shafts 17 provided concentrically on the outer periphery of the drive shaft 15 are equiangularly arranged in the circumferential direction with respect to the axis of the drive shaft 15, and the axis of the drive shaft 15 and the axis of the driven shaft 17 are arranged. Are provided at a minute angle. Each driven shaft 17 is provided with a roller 18 that is in rolling contact with the drive shaft 15 so as to be fixed in the axial direction by a bearing stopper 20 via an opposing roller bearing (for example, an angular bearing) 19. Yes.
[0035]
5 and 6, contact points (15-a to 15-c) between the rollers 18 and the outer periphery of the drive shaft 15 from the fixed end of the driven shaft 17 on the other fixed plate 16. ) Are La, Lb, and Lc, the angle between the axis of the drive shaft 15 and the axis of each driven shaft 17 is θ, and the diameter of the drive shaft 15 is D. Each member is provided so as to satisfy (Equation 1).
[0036]
[Expression 1]
Lb = La− (π · D / 3) · θ
Lc = Lb− (π · D / 3) · θ = La− (2 · π · D / 3) · θ
As shown in FIG. 3, the right end of the drive shaft 15 has a stepped shape, and the outer periphery of the first stepped portion 15 a is concentric with the left cylindrical hole of the housing 21 fixed to the base 1. The outer ring is fixed to the inner peripheral part of a pair of rolling bearings (for example, angular bearings) 22, and the inner peripheral part of the rolling bearing 22 is a bearing stopper at the screw part provided on the drive shaft 15. 23 is fixed.
[0037]
The outer periphery of the second stepped portion 15 b of the drive shaft 15 is connected to a feed drive motor 25 via a coupling member (for example, Oldham type) 24. The feed drive motor 25 is fixed to the right cylindrical hole of the housing 21 and is composed of an A-phase and B-phase pulse whose output is divided into several thousand equal parts and a Z-phase pulse generated once per turn. The rotary encoder 26 is provided.
[0038]
Further, the left end portion 15c of the drive shaft 15 is a rolling bearing (for example, a deep groove) fixed in a through hole of the support 27 fixed to the base 1 so that the outer ring can be moved concentrically in the axial direction. It is fitted to the inner ring of 28).
[0039]
In Embodiment 1 having the above-described configuration, when the feed drive motor 25 is energized, the roller 18 in contact with the outer periphery of the drive shaft 15 at the contact points 15-a to 15-c rolls, and the moving body 4 feeds. Move in the direction. The operation at this time will be described in comparison with a conventional example having the same configuration as that of the present embodiment shown in FIGS. 6 (a) and 6 (b).
[0040]
In the conventional example, the contact points 15-a ′ to 15-c ′ on the outer periphery of the drive shaft 15 of the roller 18 are arranged as shown in FIG. 6A, and the rolling locus of the roller 18 is A, B, It becomes a locus of C and rolls on a different locus. In this case, as shown in FIG. 6 (b), if the drive shaft 15 is slightly bent, the axial movement distances of 15-a ′ and 15-c ′ when the drive shaft 15 makes one rotation (this is expressed as follows). The lead amounts La ′ and Lc ′ are La ′> Lc ′, and the roller 18 slips. On the other hand, in the arrangement of the contact points (15-a to 15-c) provided so as to satisfy the expression (Equation 1) of the present embodiment, as shown in FIG. Since the rolling is performed on the same locus, the lead amount is the same even if the drive shaft 15 is bent, and the roller 18 does not slip.
[0041]
In the first embodiment, the configuration in which the angle formed by the axis of the drive shaft 15 and the axis of the driven shaft 17 is a fixed condition is shown. Next, as Embodiment 2 of the present invention, a configuration in which the angle formed by the axis of the drive shaft 15 and the axis of the driven shaft 17 is variable will be described.
[0042]
7 is a longitudinal sectional view showing a part of the friction drive device according to the second embodiment, FIG. 8 is a sectional view taken along line BB ′ in FIG. 7 of the second embodiment, and FIG. 9 is FIG. 10 is a cross-sectional view taken along the line YOY ′, FIG. 10 is a cross-sectional view taken along the line ZOZ ′ in FIG. 8 of the second embodiment, and FIG. In the following description, the same reference numerals are given to the portions that have already been described and overlapped, and detailed description thereof will be omitted.
[0043]
As shown in FIGS. 9 and 10, in this example, a roller 18a is fixed to one driven shaft 17a of three driven shafts in the axial direction, and the other driven shafts 17b and 17c are rollers that are movable in the axial direction. 18b and 18c are provided. In FIG. 9 and FIG. 10, the structural members are described symmetrically in terms of the projection, but both portions have the same configuration.
[0044]
In the other driven shafts 17b and 17c, the inner ring surface and the outer peripheral surface of the driven shafts 17b and 17c are concentrically provided with a moving ring 31 constituting the sliding bearing 30. A disc-shaped elastic plate 32 having an inner peripheral portion fixed to one end of the driven shafts 17b and 17c opposed to the one end is provided, and a moving means 33 is configured from these, and a roller 18b, 18c is configured to be movable with respect to the axial direction of the driven shafts 17b and 17c.
[0045]
The other driven shafts 17b and 17c are provided with a through hole 34 and a hole concentrically from the right end in the figure in a direction perpendicular to the axis thereof, and the hole and the outer periphery thereof are substantially fitted to each other. For example, an O-ring or the like is provided on the outer periphery, and a protruding pin 35 having a tapered tip is provided, for example, via a compression coil spring 36, and further fitted into the through hole 34 and in contact with the tapered portion of the protruding pin 35 A plurality of steel balls 37 are provided.
[0046]
In the above configuration, if compressed air or the like is supplied from the air supply port 38 provided at the right end of the driven shafts 17b and 17c, the protruding pin 35 moves to the left of the axis of the driven shafts 17b and 17c and contacts at the tapered portion. The moving steel ball 37 moves in a direction perpendicular to the axis of the driven shafts 17b and 17c to press the inner peripheral surface of the moving ring 31, and the driven shafts 17b and 17c are fixed.
[0047]
In FIG. 8, A and B are fixing plates for supporting and fixing the ends of the driven shafts 17a to 17c in directions orthogonal to each other.
[0048]
Further, a strain gauge 39 is provided between the inner and outer circumferences of the disk-shaped elastic plate 32 to detect the radial strain. FIG. 11 is a block diagram showing the configuration of the movement amount detecting means using the strain gauge 39. As shown in FIGS. 9 and 10, the pair of strain gauges 39 provided in the respective parts are connected to the bridge circuit 40, respectively. The output signal of the bridge circuit 40 is connected to the amplifier 41. The output signal is connected to, for example, the display 42, and the amount of movement of the movable rollers 18b and 18c is determined by the amount of deformation of the elastic plate 32. The movement amount detection means 43 is configured as a whole.
[0049]
According to the above configuration, the compressed air from the air supply port 38 provided at the right end portion of the driven shafts 17b and 17c according to the angle formed by the axis of the drive shaft 15 and the axis of the driven shafts 17b and 17c. With the supply turned off, the tightening force of the bearing stopper 20 of each of the driven shafts 17a to 17c is changed with reference to the movement amount detecting means 43, and the air supply port provided at the right end of the driven shafts 17b and 17c 38, by fixing the rollers 18b and 18c by supplying compressed air, the axial positions of the rollers 18b and 18c can be adjusted, and the axis of the drive shaft 15 and the shafts of the driven shafts 17a to 17c can be adjusted. It becomes possible to set the mind and the arbitrary angle.
[0050]
The first and second embodiments can cope with a case where an error in forming an angle between the axis of the drive shaft 15 and the axes of the driven shafts 17a to 17c is small.
[0051]
Therefore, as Embodiment 3 of the present invention, an angle correction unit in the case where an error in forming an angle between the axis of the drive shaft 15 and the axes of the driven shafts 17a to 17c due to an assembly error or the like will be described.
[0052]
12 is a longitudinal sectional view showing a part of a friction drive device for explaining a third embodiment of the present invention, FIG. 13 is a sectional view taken along line AA ′ in FIG. 12 of the third embodiment, and FIG. It is BB 'sectional view taken on the line in FIG. 12 of Embodiment 3. FIG.
[0053]
In FIG. 12, the right end of each driven shaft 17 is fixed to the recess of one fixed plate 16 by being equiangularly arranged in the circumferential direction with respect to the axis of the drive shaft 15, as shown in FIG. 14. A first pressing plate 46 that presses the driven shaft 17 in a direction in which the roller 18 moves away from the outer periphery of the drive shaft 15 and a second pressing plate 47 that presses the driven shaft 17 in the outer peripheral tangential direction of the driving shaft 15 are provided. ing. As shown in FIG. 15, each of the first pressing plate 46 and the second pressing plate 47 is provided with an elastic body 48 such as a coil spring provided with a sphere 45 at the pressing end portion. The right end portion of 17 is supported freely.
[0054]
In the present embodiment, the elastic body 48 is provided on the first pressing plate 46 and the second pressing plate 47 separated from the fixed plate 16. However, the elastic body 48 is directly provided on the fixed plate 16. It may be.
[0055]
On the right side surface of the other fixed plate 16, as shown in FIGS. 12, 13, and 16, a bearing (for example, a spherical bearing) 49 that fits the outer periphery of the left end of each driven shaft 17 to the inner periphery thereof. Are fixed in a circumferential direction with respect to the axis of the drive shaft 15, and each driven shaft 17 is configured to be rotatable within a plane including the rotation support point 50 of the bearing 49. ing.
[0056]
Further, the elastic body 48 of the first pressing plate 46 is pushed in the direction orthogonal to the axis of the drive shaft 15 on the opposite side of the roller 18 with the rotation support point 50 sandwiched in the concave portion of the other fixed plate 16. As shown in FIG. 17 (a), the driven shaft 17 is pressed in a direction that cancels out the moment force around the rotation support point 50 due to pressure. As shown in FIG. A first pressing means 54 comprising a third pressing plate 53 provided with a deforming portion 52 at a fixed end on the side for pressing is provided. Further, a driven shaft in a direction in which the moment force around the rotation support point 50 due to the pressing force on the elastic body 48 of the second pressing plate 47 is offset in the tangential direction of the outer periphery of the drive shaft 15 in the concave portion of the other fixed plate 16. A fourth pressing plate 57 in which a second piezoelectric element 55 as shown in FIG. 17B that presses 17 is fixed in the expansion and contraction direction, and a deforming portion 56 is provided at a fixed end on the side pressing the driven shaft 17. A second pressing means 58 made of is arranged equiangularly in the circumferential direction with respect to the axis of the drive shaft 15 and fixed.
[0057]
With the above configuration, when an appropriate energizing voltage is applied in the order of the first piezoelectric element 51 and the second piezoelectric element 55, the axis of the driven shaft 17 is the axis of the drive shaft 15 as shown by the dotted line in FIG. The outer periphery of the roller 18 and the outer periphery of the drive shaft 15 are in rolling contact with each other at a certain angle θ with respect to the shaft center.
[0058]
The moving amount L (lead amount) by which the drive shaft 15 moves the moving body 4 per rotation is:
[0059]
[Expression 2]
L = π · D · θ
For example, the relationship between the crossing angle and the lead amount L under the condition of D = 30 mm is linear as shown in the log-log graph of FIG.
[0060]
Next, angle correction means in the third embodiment for correcting the angle of the driven shaft 17 will be described with reference to the control block diagram of FIG.
[0061]
A CPU (Central Processing Unit) 61 to which a Z-phase pulse signal 60 generated once per revolution in the rotary encoder 26 is input as an interrupt signal is stored in a ROM (Read Only Memory) 62 in which an operation program is written. A RAM (Random Access Memory) 63 for storing data and a counter 64 to which the A and B phase output signals of the position detecting means 11 are input using the rising edge of the Z phase pulse signal as a trigger signal are connected.
[0062]
A drive amplifier 65 connected to each first piezoelectric element 51, a constant voltage circuit 66 for outputting a fixed constant voltage, and a switch 67 for turning on / off the output signal of the constant voltage circuit 66 by an external signal. The output means 68 of 1 is comprised, and the input signal of the drive amplifier 65 is output from CPU61 via each switch 67. FIG. Further, an output signal of the CPU 61 is inputted to each second piezoelectric element 55 via a D / A (digital / analog) converter 69 and a drive amplifier 70, and the D / A converter 69 and the drive amplifier are inputted. 70 constitutes a second output means 71.
[0063]
Further, the CPU 61 is connected with a data input unit 72 for inputting the data of the lead amount L and the setting allowable error data ε, and the angle correction means 73 is configured by the entire configuration shown in FIG.
[0064]
An operation flow based on the control of the CPU 61 in the third embodiment having the above-described configuration will be described with reference to flowcharts shown in FIGS.
[0065]
In FIG. 21, the CPU 61 reads the read amount data L and its set allowable error data ε inputted in advance (S1), waits for a command signal 74a from the host computer (not shown) of the entire apparatus (S2), and receives a command from the host computer. When the command signal 74a is turned on, the angle calculation means 75, which is a function provided in the CPU 61, calculates the intersection angle θ based on the equation (Equation 2) (S3). Thereafter, the drive signal of the switch 67 is turned off, the signal to each first piezoelectric element 51 is turned off, and the first pressing means 54 is opened (S4). In step (S4), i = a, b, and c indicate numbers corresponding to the number of installed drive amplifiers 65, D / A converters 69, and the like.
[0066]
Shifting to the flow of FIG. 22, digital data corresponding to the crossing angle θ calculated by the angle calculation means 75 is sent to the D / A converter 69 (S5), and the second piezoelectric element is sent via the drive amplifier 70. A displacement voltage corresponding to the calculated intersection angle θ is applied to the element 56. Thereafter, the drive signal to the switch 67 is turned ON, and the output signal of the constant voltage circuit 66 set to an appropriate voltage is energized to the first piezoelectric element 51 through the drive amplifier 65, and the first pressing means 54. Presses the driven shaft 17 (S6). In this state, the feed drive motor 25 starts to rotate (S7), and the movement amount Xi of the moving body 4 due to one rotation of the drive shaft 15 is taken by using the rise of the Z-phase pulse signal of the rotary encoder 26 as a trigger signal. (S8) Thereafter, the angle error (difference data Δθi) is obtained by the error calculation means 76, which is a function provided in the CPU 61 for calculating the relative angle error (S9). If the movement amount Xi of the moving body 4 is equal to or smaller than the preset setting allowable error data ε (YES in S10) by the voltage correction means 77 which is a function provided in the CPU 61, the angle data θi is stored in the RAM 63. (S11), if large (No in S10), if the difference data Δθi is larger than 0, Δθi is subtracted from the set angle data (S12), and if the difference data Δθi is smaller than 0 In step S13, Δθi is added to the set angle data. In the voltage correction means 77, these operations are repeated until ε ≧ Xi.
[0067]
Steps (S4) to (S13) are a subroutine, and the above operation is sequentially performed for each drive amplifier 65 and each D / A converter 69 in FIG. 20, and when all of them are completed, the drive signal of the switch 67 is turned off. Then, the signal to the first piezoelectric element 51 is turned OFF, and the first pressing means 54 is opened. Digital data corresponding to each stored angle data θi is output to each D / A converter 69 (S14). Thereafter, the drive signal of the switch 67 is turned on, and a signal to the first piezoelectric element 51 is output. Turned on, the first pressing means 54 presses the driven shaft 17 (S15).
[0068]
Here, the feed drive motor 25 is driven (S16), and the movement amount Xf of the moving body 4 is taken in again using the rise in the Z-phase pulse signal of the rotary encoder 26 as a trigger signal (S17), and the movement amount Xf is set. It is confirmed that the error is equal to or less than the set allowable error data ε (S18), the setting completion signal 74b is turned ON to the host computer (S19), and the operation is completed.
[0069]
According to the configuration of the third embodiment, even if the crossing angle between the axis of each driven shaft 17 and the axis of the drive shaft 15 varies due to a mechanical position error due to processing, assembly error, or the like. The angular position of each driven shaft 17 can be corrected.
[0070]
Next, Embodiments 4 and 5 of the present invention will be described. Description of overlapping parts already described in the first to third embodiments is omitted.
[0071]
In the piezoelectric element which is a constituent element of the third embodiment, the relationship between the displacement amount and the applied voltage generally has a hysteresis characteristic as shown in FIG. Therefore, when the applied voltage to the first piezoelectric element 51 is relatively small, there is no problem because the residual displacement amount Dp when the first pressing means 54 is opened is very small, but the applied voltage is relatively large. In other words, if the pressing amount of the roller 18 against the drive shaft 15 (this is generally referred to as preload) is increased, the remaining displacement amount Dp increases, which may cause a case where the roller 18 cannot be completely opened.
[0072]
Therefore, in the fourth embodiment, as shown in FIG. 24A, a deformation amount measuring means 78 such as a strain gauge that detects the deformation amount of the deformation portion 52 in the third pressing plate 53 by detecting a change in resistance value, for example. The output signal of the deformation measuring means 78 and the set voltage of the constant voltage circuit 66 are compared to perform servo control.
[0073]
FIG. 25 is a block diagram showing the configuration of the servo control system of the fourth embodiment. As for the output signal of the constant voltage circuit 66, the drive signal is input from the CPU 61, the output signal of the constant voltage circuit 66 is input when ON, and The signal is input to the differential amplifier 81 via the switch 80 connected to 0 V (GND) when OFF. Further, the output signal of the deformation amount measuring means 78 is input to the differential amplifier 81 via a bridge circuit 82 that detects a change in resistance value and an amplifier 83 that amplifies a minute signal of the bridge circuit 82. Then, the output signal of the constant voltage circuit 66 connected to the switch 80 or the 0 V (GND) signal is subtracted, and the output signal drives the first piezoelectric element 51 via the compensation circuit 84 and the gain adjuster 85. Input to the amplifier 65. Servo control means 86 of the first output means 68 is constituted by the switch 80 and the subsequent drive to the drive amplifier 65.
[0074]
The frequency characteristics of the input signal of the drive amplifier 65 and the amount of displacement of the first pressing means 54 are a secondary system as shown in FIG. 26, and a general servo system stability index is obtained by adjusting the compensation circuit 84. The phase margin of 40 degrees or more and the gain margin of 15 dB or more are set.
[0075]
According to the configuration of the fourth embodiment, even if the applied voltage of the first piezoelectric element 51 is relatively large, in other words, even if the pressing amount of the roller 18 against the drive shaft 15 is large, the servo control means 86 is set to the target value. Since the output signal of the constant voltage circuit 66 or the 0V (GND) signal of the circuit and the output signal from the deformation amount measuring means 78 are compared and converged to the target value, the residual displacement amount Dp described with reference to FIG. Disappear.
[0076]
For the same reason as described in the fourth embodiment, the second piezoelectric element 55 also has a hysteresis characteristic. Therefore, when a large lead amount is set, it takes time for the correction operation by the voltage correction unit 77 described in the third embodiment.
[0077]
Therefore, in the fifth embodiment, as shown in FIG. 24B, a deformation amount measuring means 79 such as a strain gauge that detects the deformation amount by changing the resistance value is applied to the deformation portion 56 in the fourth pressing plate 57, for example. As shown in FIG. 27, servo control means 88 having the same configuration as the servo control means 86 of the fourth embodiment, which uses the output signal of the D / A converter 69 as a target value, is provided.
[0078]
In the configuration of the fifth embodiment, since the output signal from the D / A converter 69 serving as the target value is compared with the output signal from the deformation amount measuring means 79 and converges to the target value, the above-described residual displacement amount Dp is generated. Disappear.
[0079]
In the third to fifth embodiments, the pressing adjustment range of the driven shaft 17 and the drive shaft 15 and the crossing angle adjustment range are the first piezoelectric element 51 used for the first pressing means 54 and the second pressing means 58. For example, when the lead setting condition is large, it cannot be handled.
[0080]
Therefore, as a sixth embodiment of the present invention, a configuration that can cope with a large lead setting condition will be described.
[0081]
28 is a longitudinal sectional view showing a part of the friction drive device of the sixth embodiment, FIG. 29 is a sectional view taken along the line AA ′ in FIG. 28 of the sixth embodiment, and FIG. 30 is in FIG. 28 of the sixth embodiment. BB ′ sectional view, FIG. 31 is a sectional view taken along line CC ′ in FIG. 28 of the sixth embodiment, and FIG. 32 is a sectional view taken along line DD ′ in FIG.
[0082]
In the sixth embodiment, the first guide portion 90 is provided in the concave portion of one fixed plate 45b fixed to the lower portion of the projecting portion 14 of the moving body 4 in the direction in which the driven shaft 17 is pressed. A third pressing plate 53 provided so as to be fitted to the first fixing screw, a first adjustment screw 91 provided on the fixing plate 16 in a direction in which the driven shaft 17 is pressed, and a female screw portion provided on the third pressing plate 53. Thus, the position can be adjusted in the direction in which the driven shaft 17 is pressed.
[0083]
Furthermore, a second guide portion 92 is provided in the concave portion of the fixed plate 16 in a direction in which the driven shaft 17 is pressed in the tangential direction of the outer periphery of the drive shaft 15. Of the pressing plate 57, the second adjusting screw 93 provided in the direction in which the driven shaft 17 is pressed in the tangential direction of the outer periphery of the drive shaft 15 and the rear end side surface of the fourth pressing plate 57. The position can be adjusted in a direction in which 17 is pressed in the tangential direction of the outer periphery of the drive shaft 15.
[0084]
Further, after the position adjustment of the third pressing plate 53 and the fourth pressing plate 57, as shown in FIG. 31, the first fixing tool 94 and the second fixing tool 95 are fixed in the feed direction, respectively. It is configured.
[0085]
In the sixth embodiment, as shown in FIGS. 30 and 32, the other fixing plate 16 is provided with the first pressing plate 46, the second pressing plate 47, and the sphere 45 described in FIGS. The body 48 and the like are provided, and, similarly to the structure described with reference to FIGS. 29 and 31, the first pressing plate 46 and the second pressing plate 47 are provided with adjusting screws 96 and 97, and the fixing tool. Although it is set as the structure fixed by 98,99, when the deformation | transformation stroke of the elastic body 48 is large enough, it is not necessary to use this structure.
[0086]
According to Embodiment 6 of the said structure, before performing the angle correction operation demonstrated in Embodiment 3-5 with respect to the big lead conditions to set, the 3rd press board 53 and the 4th press board are carried out manually. 57 is adjusted in the vicinity of the setting lead by the first adjustment screw 91 and the second adjustment screw 93, respectively, and set so as to be within the maximum expansion / contraction amount of the first piezoelectric element 51 and the second piezoelectric element 55. After that, an angle correction operation is performed.
[0087]
In the third to sixth embodiments, the pressing force of the roller 18 against the drive shaft 15 (hereinafter referred to as preload) is not directly controlled, and the expansion / contraction amount of the first piezoelectric element 51 is set according to the command value. In this case, the current preload amount of the roller 18 with respect to the drive shaft 15 cannot be quantitatively confirmed.
[0088]
Therefore, as a seventh embodiment of the present invention, a configuration for controlling the preload on the drive shaft 15 of the roller 18 will be described.
[0089]
FIG. 33 is a cross-sectional view showing the main part of the friction drive device of the seventh embodiment, and the outer periphery of the driven shaft 17 between the third pressing plate 53, the rotation support point 50 (see FIG. 12), and the roller 18. A deformation amount measuring means 100 for detecting a deformation amount in the pressing direction of the driven shaft 17 is provided in the part.
[0090]
FIG. 34 is a block diagram showing the configuration of the variable pressure control means of the seventh embodiment. The first output means 68 includes the variable voltage circuit 101, the output signal of the variable voltage circuit 101 at one terminal and 0V at the other terminal. A changeover switch 102 that is input and turned on / off by an external signal, a deformation amount measuring means 100 that detects a deformation amount in the pressing direction of the driven shaft 17, and a pressure setting signal that is an output signal 103 of the changeover switch 102 and a deformation amount measurement. The servo control means 86 having the same configuration as that shown in FIG. 23, which includes an operation amplifier 81 for comparing the current pressing amount as the output signal 104 of the means 100, and the like.
[0091]
In the seventh embodiment configured as described above, the amount of preload applied to the drive shaft 15 of the roller 18 provided on each driven shaft 17 is detected as the amount of deformation of the driven shaft 17 in the pressing direction. In this case, the pressing is performed within the elastic deformation of the driven shaft 17, and it goes without saying that the relationship of the preload amount to the voltage applied to the first piezoelectric element 51 is linear. In the seventh embodiment, since the output of the variable voltage circuit 101 is used as a preload setting signal, the preload amount can be manually set freely.
[0092]
FIG. 35 is a block diagram showing a modification of the first output means 68 in the seventh embodiment. In the configuration example shown in FIG. 35, the variable voltage circuit 101 in the configuration of the first output means 68 shown in FIG. As a D / A converter 105 connected to the CPU 61, the switch 102 is used as a servo by comparing the pressing setting signal as the output signal 106 with the current pressing amount as the output signal 104 of the deformation measuring means 100. It is configured to control. In this configuration, the pressure release at the time of angle adjustment is when digital data that outputs 0 V from the D / A converter 105 is output. For example, appropriate preload setting condition data is stored in the ROM 62 (see FIG. 15). If it is described as a constant in the program, an appropriate preload can be set instantaneously, and it is not necessary to perform a preload readjustment operation associated with secular change due to wear of the roller 18 or the drive shaft 15.
[0093]
【The invention's effect】
As described above, according to the present invention, at least two driven shafts are arranged equiangularly in the circumferential direction with respect to the axis of the drive shaft, and are inclined with respect to the drive shaft at an inclination angle θ. The distance between the fixed end of two driven shafts of the at least two driven shafts on the fixed plate and the contact point between the roller provided on the driven shaft and the drive shaft is set to La and Lb, respectively. When the diameter of the drive shaft is D, the drive shaft is bent due to processing, assembly errors, and the like by having a relationship of La = Lb− (π · D / 3) · θ. Even if there is no slip due to lead error between the drive shaft and each driven shaft roller, Further, since it is possible to correct the variation in the crossing angle between each driven shaft and the drive shaft caused by a mechanical position error due to processing, assembly error, etc., the axis between each roller and the drive shaft is formed. The angle can be set precisely, and no slippage occurs due to lead error between the drive shaft and each driven shaft roller. A friction drive device that can realize stable feed control and improve feed accuracy is realized.
[Brief description of the drawings]
FIG. 1 is a plan view of a friction drive device for explaining Embodiment 1 of the present invention.
FIG. 2 is a right side view of the friction drive device according to the first embodiment.
FIG. 3 is a longitudinal sectional view showing a part of the friction drive device according to the first embodiment.
FIG. 4 is a perspective view for explaining a main part in the first embodiment.
FIG. 5 is a development view of a drive shaft in the first embodiment.
6 is a development view of a drive shaft in Embodiment 1. FIG.
FIG. 7 is a longitudinal sectional view showing a part of a friction drive device according to a second embodiment of the present invention.
8 is a cross-sectional view taken along line BB ′ in FIG. 7 according to the second embodiment.
9 is a cross-sectional view taken along line YOY ′ in FIG. 8 according to the second embodiment.
FIG. 10 is a cross-sectional view taken along the line ZZ ′ in FIG. 8 according to the second embodiment.
FIG. 11 is a block diagram illustrating a configuration of a movement amount detection unit according to the second embodiment.
FIG. 12 is a longitudinal sectional view showing a part of a friction drive device for explaining a third embodiment of the present invention.
13 is a cross-sectional view taken along line AA ′ in FIG. 12 of the third embodiment.
14 is a cross-sectional view taken along line BB ′ in FIG. 12 of the third embodiment.
FIG. 15 is an explanatory view showing, in an enlarged manner, the vicinity of an elastic body installation portion in Embodiment 3.
FIG. 16 is a cross-sectional view showing a rotation support point portion in the third embodiment.
FIG. 17 is an explanatory view showing, in an enlarged manner, a pressing plate portion in the third embodiment.
FIG. 18 is an explanatory diagram of an intersection angle between a driven shaft and a drive shaft in the third embodiment.
FIG. 19 is a diagram showing the relationship between the crossing angle and the lead amount in the third embodiment.
FIG. 20 is a block diagram showing a configuration of angle correction means in the third embodiment.
FIG. 21 is a flowchart showing an operation flow based on CPU control in the third embodiment.
FIG. 22 is a flowchart of a subroutine in the flowchart of FIG.
FIG. 23 is a diagram showing a relationship between applied voltage and displacement amount of a general piezoelectric element.
FIG. 24 is a configuration diagram of a main part of a friction drive device for explaining a fourth embodiment of the present invention.
FIG. 25 is a block diagram showing a configuration of a servo control system in the fourth embodiment.
FIG. 26 is a frequency characteristic diagram of the displacement amount of the pressing means with respect to the input signal of the drive amplifier in the fourth embodiment.
FIG. 27 is a block diagram showing a configuration of a servo control system in the friction drive device according to the fifth embodiment of the present invention.
FIG. 28 is a longitudinal sectional view showing a part of a friction drive device according to Embodiment 6 of the present invention.
FIG. 29 is a cross-sectional view taken along line AA ′ in FIG. 28 of the sixth embodiment.
30 is a BB ′ cross-sectional view in FIG. 28 according to the sixth embodiment.
FIG. 31 is a sectional view taken along line CC ′ in FIG. 28 of the sixth embodiment.
32 is a sectional view taken along the line DD ′ of FIG. 28 in Embodiment 6. FIG.
FIG. 33 is a cross-sectional view showing the main part of a friction drive device for explaining Embodiment 7 of the present invention.
FIG. 34 is a block diagram showing a configuration of variable pressing control means in the seventh embodiment.
FIG. 35 is a block diagram showing a configuration of a modified example of the first output means in the seventh embodiment.
[Explanation of symbols]
3 Rolling bearing
4 moving objects
5 Turntable
11 Position detection means
15 Drive shaft
17 Driven shaft
16 Fixed plate
18 Laura
25 Feed drive motor
26 Rotary encoder
39 Strain gauge
43 Movement amount detection means
45 balls
46 1st press board
47 Second pressing plate
48 Elastic body
51 First piezoelectric element
53 Third press plate
54 1st press means
55 Second Piezoelectric Element
57 Fourth pressure plate
58 Second pressing means
61 CPU
64 counters
65 Drive amplifier
66 Constant voltage circuit
67 switch
68 First output means
69 D / A converter
70 Drive amplifier
71 Second output means
72 Data input section
73 Angle correction means
75 Angle calculation means
76 Error calculation means
77 Voltage correction means
78 Deformation measuring means
81 Working amplifier
82 Bridge circuit
83 Amplifier
84 Compensation circuit
85 Gain adjuster
86,88 Servo control means
90 First guide
91 First adjustment screw
92 Second guide
93 Second adjustment screw
94 First fixture
95 Second fixture
101 Variable voltage circuit
102 switch
105 D / A converter

Claims (6)

A drive shaft, a roller provided on each of at least two driven shafts inclined at an inclination angle with respect to the drive shaft, and a roller that is in rolling contact with an outer periphery of the drive shaft; and the driven shaft and the roller by rotation of the drive shaft A movable body that moves together with the movable body, a fixed plate that is fixed to the movable body and through which the drive shaft passes and the driven shaft is fixed, and a guide mechanism that guides the movable body in the axial direction of the drive shaft. In the friction drive device
The driven shafts are arranged equiangularly in the circumferential direction with respect to the axis of the drive shaft, and are inclined at an inclination angle θ with respect to the drive shaft, and the at least two driven shafts in the fixed plate When the distance from the fixed end of the two driven shafts to the contact point between the roller provided on the driven shaft and the drive shaft is La and Lb, respectively, and the diameter of the drive shaft is D , a La = Lb- (π · D / 3) · θ friction drive apparatus configured to have the relationship,
One end of the driven shaft is supported by a spherical bearing, and the other end is pressed in a direction in which the roller provided on the driven shaft is separated from the outer periphery of the drive shaft with the rotation support point being the center of the spherical bearing as a fulcrum. Free driving by a first elastic body and a second elastic body pressing in the tangential direction of the outer periphery of the drive shaft, the drive shaft being fixed to the movable body on the opposite side of the roller across the rotation support point, A first pressing means that presses the driven shaft in a direction that cancels out the moment force around the rotation support point due to the pressing force of the first elastic body in a direction perpendicular to the axis of the axis, and a tangential direction of the outer periphery of the drive shaft The second pressing means for pressing the driven shaft in a direction to cancel the moment force around the rotation support point due to the pressing force of the second elastic body, and pressing / releasing the first pressing means, Move the roller in the axial direction of the driven shaft. The roller is movable in the axial direction based on a first output means for controlling to be fixed, an origin detection signal per rotation of the drive shaft, and an output signal of the roller movement amount detection means An angle error calculating means for calculating an inclination angle error with respect to the driven shaft in which the roller provided on the driven shaft is fixed in the axial direction, and a correction signal obtained by increasing or decreasing an output signal corresponding to the calculated angle from the current applied signal. An angle correction means comprising a second output means for applying to the pressing means of the friction drive device . The first output means includes a constant voltage circuit, a changeover switch to which an output signal of the constant voltage circuit is input and turned on / off by an external signal, and a deformation amount provided in a deformation portion of the first pressing means. It is characterized by comprising measuring means, and servo control means for servo-control by comparing a pressing expansion / contraction setting signal which is an output signal of the changeover switch and a current pressing expansion / contraction amount which is an output signal of the deformation amount measuring means The friction drive device according to claim 1. The first output means includes a variable voltage circuit, a change-over switch to which an output signal of the variable voltage circuit is input and turned on / off by an external signal, the first pressing means, the rotation support point, and the A deformation amount measuring means provided between the rollers for detecting a deformation amount in the pressing direction of the driven shaft at an outer peripheral portion of the driven shaft; a pressing setting signal which is an output signal of the changeover switch; and the deformation amount measuring means. friction drive according to claim 1, characterized by being configured and a servo control means for servo-controlling by comparing the current pressing amount is output signal. The first output means is provided between one digital / analog converter, the first pressing means, the rotation support point, and the roller, and presses the driven shaft on the outer peripheral portion of the driven shaft. Deformation amount measuring means for detecting the amount of deformation in the direction, and servo control for servo-control by comparing the pressing setting signal as the output signal of the digital / analog converter with the current pressing amount as the output signal of the deformation amount measuring means 2. The friction drive apparatus according to claim 1 , wherein the friction drive apparatus comprises means. The second output means includes a digital signal / analog converter, a deformation amount measuring means provided at a deformation portion of the pressing plate, a press expansion / contraction setting signal which is an output signal of the digital signal / analog converter, and the deformation amount. friction drive device according to claim 1, wherein comparing the current pressing deformation amount which is the output signal of the measuring means, characterized by being configured and a servo control means for performing a servo operation. A first guide portion provided in a direction of pressing the driven shaft in the fixed plate fixed to the movable body, a third press plate provided to fit in the first guide portion, A first adjusting screw provided in a direction in which the driven shaft of the fixed plate is pressed; and a female screw portion provided in the third pressing plate to which the first adjusting screw is screwed. Enables position adjustment in the direction of pushing the driven shaft,
A second guide portion provided in a direction in which the driven shaft of the fixed plate is pressed in a direction tangential to the outer periphery of the drive shaft; and a fourth press plate provided so as to be fitted to the second guide portion. A second adjusting screw provided in a direction for pressing the driven shaft of the fixed plate in a tangential direction of the outer periphery of the drive shaft, and the driven shaft is moved by the rear side surface of the fourth pressing plate. The friction drive device according to any one of claims 1 to 5 , wherein the position of the drive shaft can be adjusted in a direction of pressing in a tangential direction of the outer periphery of the drive shaft .

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