JP2006310686A - Positioning table apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning table apparatus where a load is positioned in a lockable way, while the apparatus is inexpensively manufactured. <P>SOLUTION: Since a detector S is provided for detecting a hydrostatic pad 12b of a hydrostatic bearing 12 seated on a base plate 12g, it is discriminated precisely with a signal from the detector S whether a table 13 is locked to a board 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a positioning table device that can position a load at a predetermined angle.

  The liquid crystal panel used for the flat panel display has a relatively large size, for example, 730 mm × 920 mm, and there are considerable weights and jigs included. However, the liquid crystal panel may be further increased in the future according to market demands. is expected. By the way, when processing or inspecting a liquid crystal panel, a device for moving the liquid crystal panel is required so that the tool faces the part to be processed or the part to be inspected with high accuracy.

Here, Patent Document 1 discloses an indexing device that rotatably supports a rotating body with respect to a fixed body. In the indexing device of Patent Document 1, the rotating body is supported with respect to the stationary body in the radial direction and the thrust direction by using a hydrostatic fluid bearing.
JP-A-8-303464

  However, it is necessary to lock the rotating body relative to the fixed body, for example, when performing highly accurate processing or inspection, or when the rotating body and the fixed body are moved together. Here, it is possible to lock the rotating body with respect to the fixed body using a separate locking device, but this causes an increase in cost.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a positioning table device that can position a load in a lockable manner while being inexpensive.

In order to achieve the above object, a positioning table device of the present invention is a positioning table device capable of positioning a load,
A base with a base shaft attached;
A rotatable table that supports the load; and
A bearing disposed between the base shaft and the table and supporting a radial force of the table;
A hydrostatic bearing disposed on one of the base and the table and supporting an axial force of the table;
A base plate disposed opposite to the hydrostatic bearing on the other of the base and the table;
A detection device for detecting that the hydrostatic bearing is seated on the base plate;
And a driving device for rotating the table with respect to the base.

  The static pressure bearing can discharge the gas supplied from the outside toward the base plate, and can support the table in a floating state with respect to the base using the static pressure generated therebetween. However, if the supply of gas to the hydrostatic bearing is interrupted, the static pressure between the hydrostatic bearing and the base plate disappears, and if they come into contact, the table is applied to the base using frictional force. Can be locked. Here, the interruption of the gas supply to the hydrostatic bearing can be determined based on, for example, a signal from an electromagnetic valve disposed between the hydrostatic bearing and the gas supply source. The table may not be locked immediately due to the influence, and there is a problem that the certainty in determining whether or not the table is locked is low. On the other hand, it is conceivable to separately provide an electrostatic sensor or the like. In such a case, although the contact / non-contact of the part where the electrostatic sensor is provided is known, the actual contact between the hydrostatic bearing and the base plate is possible.・ There is a problem that non-contact cannot be identified.

  On the other hand, according to the positioning table device of the present invention, since the detection device for detecting that the hydrostatic bearing is seated on the base plate is provided, the signal from the detection device is applied to the base. On the other hand, it can be directly and accurately determined whether or not the table is locked.

  Further, the hydrostatic bearing has a conductive hydrostatic pad, the base plate has electroconductivity, and the detector detects electrical continuity between the hydrostatic pad and the base plate, It can be directly determined whether or not the table is locked to the base.

  Furthermore, if the surface of the base plate is coated with a conductive film, a non-conductive material can be selected as the material of the base plate, and if the film is hard, the wear of the base plate can be selected. Can also be suppressed. As such a film, titanium nitride or the like is preferable.

  It is preferable that the table and the bearing that supports the radial force of the table be connected by a leaf spring because the table can easily move in the axial direction.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a top view of the positioning table device of the present embodiment, and FIG. 2 is a cross-sectional view of the configuration of FIG. 1 taken along line II-II and viewed in the direction of the arrow. 3 is an enlarged view showing an arrow III part of FIG. 2, FIG. 4 is an enlarged view showing an arrow IV part of FIG. 2, and FIG. 5 is a diagram showing the configuration of FIG. It is the figure which cut | disconnected and looked at the arrow direction.

  In FIG. 2, the guide rail 1 is disposed on the surface plate G. The base plate 10 arranged on the surface plate G has sliders 2 and 2 engaged with the guide rail 1 attached to the lower surface thereof. Accordingly, the base 10 is movable in the left-right direction in FIG. 2 as the sliders 2 and 2 move along the guide rail 1. The sliders 2 and 2 and the guide rail 1 constitute a linear guide. A base shaft 11 and three hydrostatic bearings 12 are fixed to the upper surface of the base 10, and a table 13 is further disposed.

  In FIG. 3, the inner ring of a pair of angular contact ball bearings 14 and 14 abuts the stepped portion 11a on the base side of the outer periphery of the base shaft 11 disposed so as to protrude into the central opening 13a of the table 13. Further, they are fitted together and further pressed in the axial direction toward the step portion 11a by the nut 16 screwed into the male screw portion at the tip of the base shaft 11 via the inner ring spacer 15. The outer rings of the angular contact ball bearings 14, 14 are fitted in the hollow cylindrical holder 17 so as to abut against the inner peripheral flange portion 17 a of the end portion thereof, and are further fixed by a fixing member 18 that is attached and fixed to the holder 17. The end portion inner circumferential flange portion 17a is pressed in the axial direction. With this configuration, it is possible to apply a preload to the angular contact ball bearings 14 and 14. Since the angular contact ball bearings 14, 14 need only apply a force in the radial direction, a low load capacity is sufficient.

  The outer peripheral flange 17b of the holder 17 to which the outer rings of the angular contact ball bearings 14, 14 are fixed and the lower surface of the table 13 are connected in a bridging manner by a leaf spring 19 which is an elastic member. Are fixed to each using bolts B. As shown in FIG. 1, the plate spring 19 has only two opposing sides fixed by bolts B, thereby ensuring appropriate flexibility. The side of the leaf spring 19 to be fixed is preferably in a direction orthogonal to the moving direction of the base 10. Since only the tensile stress acts on the leaf spring 19 during acceleration / deceleration, the influence on the posture of the table 13 can be eliminated. In order to ensure the rigidity at the time of rotating the table, it is desirable that the four bolts B positioned at the outermost position are positioned at the apexes of the square. A preload can also be applied to the angular contact ball bearings 14, 14 using the biasing force of the leaf spring 19. When a sliding bearing is used in place of the angular contact ball bearings 14, 14, the leaf spring 19 may be omitted.

  In FIG. 4, the hydrostatic bearing 12 is disposed on the bottom surface of the short body 12a made of hard metal such as SUS440C, which is fixed to the bolt hole 13b provided in the table 13 using the bolt B, and the main body 12a. It is composed of a porous graphite-made static pressure pad 12b disposed in the disk-shaped hole 12f and an electromagnetic valve 12c (FIG. 1) for controlling the supply of gas to the main body 12a. In order to suppress response delay, it is preferable that the hose H connecting the electromagnetic valve 12c and a connector (described later) attached to the main body 12a is as short as possible. Since the rotation amount of the table 13 is small, the electromagnetic valve 12 c can be arranged on the base 1 by using the flexible hose H.

  Inside the main body 12a, a supply path 12d for supplying air supplied via the electromagnetic valve 12c to the static pressure pad 12b and an exhaust path 12e are formed. The supply path 12d communicates with the supply connector SC provided on the side surface of the main body 12a and the disc-shaped hole 12f. The exhaust path 12e is provided with the exhaust connector EC provided on the side surface of the main body 12a and the outer periphery of the lower surface of the main body 12a. It communicates with a circumferential groove 12h provided in the vicinity.

  Opposite to the lower surface of the main body 12a, a disk-like base plate 12g coated with a titanium nitride film on the ceramic surface (SUS440C may be used, but the bolt holes need to be insulated) is provided with a thin plate-like insulating material 30. And is fixed on the base 10 by a bolt B. Therefore, the base plate 12 and the base 10 are in an insulated state. The titanium nitride film has a high hardness of 20 to 25 GPa and can suppress wear and has a friction coefficient of 0.3 to 0.45. Therefore, the titanium nitride film does not move if the acceleration applied to the table 13 is 0.3 G or less. Therefore, the angular contact ball bearings 14 and 14 can have a small capacity.

  In the present embodiment, the conductive static pressure pad 12b made of porous graphite and the conductive surface of the base plate 12g are connected to the detection device S by the electrical wiring L. Further, an ON / OFF signal from the solenoid valve 12c (if the ON signal is supplied, air is supplied to the static pressure bearing, and if it is an OFF signal, supply is interrupted) is input to the detection device S.

  Further, a spacer 12j is disposed between the table 13 and the main body 12a, and the position of the hydrostatic bearing 12 in the height direction can be adjusted by selecting the thickness thereof. The remaining two hydrostatic bearings 12 have the same configuration. In the present embodiment, since three hydrostatic bearings 12 are arranged at an equal angle, it is easy to perform height adjustment and parallelism adjustment. In this case, when the outer diameter of the table 13 is D, the deformation of the table 13 is most suppressed if the center of the hydrostatic bearing 12 is located at a position separated by 0.635 D from the axis of the base shaft 1. Therefore, the plate thickness can be reduced and the weight can be reduced (see JP 2001-185601 A).

  In FIG. 1, a motor 21 is attached to a frame 20 fixed to the upper surface of the base 10. The rotating shaft 21 a of the motor 21 is connected to the screw shaft 23 b of the ball screw mechanism 23 through the coupling 22. The ball screw mechanism 23 includes a bearing 23a, a screw shaft 23b, and a nut (not shown) in the rolling wheel case 24, and converts the rotational motion of the screw shaft 23b into the axial motion of the nut (not shown). Is. The screw shaft 23 b is connected to the rolling wheel case 24. A rolling wheel 25 is rotatably supported in the rolling wheel case 24. The rolling wheel 25 is freely rollable along the side surface of the arm 13 c protruding in the radial direction from the outer periphery of the table 13. A coil spring 26 having one end attached to the arm 13c and the other end attached to the frame 20 via an adjustment bolt 27 causes the table 13 to be constantly pressed counterclockwise in FIG. 1 (that is, the side surface of the arm 13c is always pressed against the rolling wheel 25). So that it is energized. The urging force of the coil spring 26 can be adjusted by screwing or loosening the adjustment bolt 27. The motor 21, the coupling 22, the ball screw mechanism 23, the rolling wheel case 24, the rolling wheel 25, the coil spring 26, and the arm 13c constitute a driving device.

  The operation of this embodiment will be described. With a measurement object (workpiece) (not shown) placed on the table 13, the position is measured, and the table 13 is rotated so as to have a predetermined angle. This is for the purpose of angle correction when an object to be measured (workpiece) is placed. Thereafter, the workpiece (workpiece) is moved to the machining position or moved while machining.

  More specifically, the electromagnetic valve 12c is controlled to supply air to the static pressure pads 12b of the three static pressure bearings 12 via the supply connector SC and the supply path 12d, and from the base plate 12g using the static pressure. By floating, the table 13 is moved in the axial direction (upward in FIG. 2). The air blown out from the static pressure pad 12b is discharged to the outside.

  Since the plate spring 19 has low vertical rigidity, it hardly prevents the table 13 from moving in the axial direction. When the table 13 rises, the motor 21 is driven to push out or retract the rolling wheel case 24, and the arm 13c is rotated clockwise in FIG. Since it rotates counterclockwise by the urging force of the coil spring 26 so as to follow the moving wheel 25, the table 13 can be rotated within a range of ± 1 °, for example. Accordingly, the object to be measured (workpiece) placed on the table 13 can be rotated slightly.

  After the table 13 is slightly rotated in this way, the solenoid valve 12c is controlled to cut off the supply of air to the static pressure pads 12b of the three static pressure bearings 12, and the static pressure pad 12b is seated on the base plate 12g. . The table 13 is held so as not to move relative to the base 10 by the frictional force acting between the static pressure pad 12b and the base plate 12g. When a higher holding force is required, suction is performed from the peripheral groove 12h, but suction may be performed from the static pressure pad 12b. This controls the solenoid valve 12c to connect to an external exhaust pump (not shown) so that air is sucked from the hydrostatic pads 12b of the three hydrostatic bearings 12 via the supply connector SC and the supply path 12d. Anyway. In such a case, the suction force of the air to the base plate 12g can be obtained by sucking air, so that the table 13 can be firmly held.

  Thereafter, the workpiece (workpiece) is moved to the machining position or moved while machining. This moves the base 10 to the inspection position by moving the sliders 2 and 2 along the guide rail 1 with respect to the surface plate G. At this time, since the leaf spring 19 extends in the moving direction (horizontal direction), the rigidity is increased in this direction, so that the table 13 can be supported stably. Further, the radial force applied to the table 13 during acceleration / deceleration is supported by the angular contact ball bearings 14, 14, but the electromagnetic valve 12 c is controlled to the static pressure pads 12 d of the three hydrostatic bearings 12. When the air supply is shut off and the static pressure pad 12d is seated on the base plate 12g, a frictional force is generated between them, so that almost no force is applied to the angular contact ball bearings 14,14. Accordingly, no positional deviation occurs.

  A specific seating detection operation will be described below with reference to the flowchart of FIG. In step S101 of FIG. 6, the solenoid valve 12c is turned on to supply air to the static pressure pads 12b of the three hydrostatic bearings 12 via the supply connector SC and the supply path 12d, and the base plate 12g is used using static pressure. The table 13 is moved in the axial direction (upward in FIG. 2) by levitating from above.

  Further, in step S102, the detection device S that has received the ON signal from the electromagnetic valve 12c detects contact (ie, seating) between the static pressure pad 12b and the base plate 12g based on whether there is electrical continuity. If even one of the three hydrostatic bearings 12 is electrically connected, a warning is issued in step S103, assuming that the hydrostatic pad 12b and the base plate 12g remain in contact. As a warning mode, a warning sound such as a display on a host controller or a monitor (not shown) or a buzzer may be considered. While the warning is issued, a measure for prohibiting the operation of the motor 21 may be taken.

  On the other hand, if the detecting device S detects that the hydrostatic pads 12b of all the hydrostatic bearings 12 are completely lifted and are not in contact with the base plate 12g, the warning is stopped. In such a case, the operation of the motor 21 is allowed in step S104. In such a state, control may be performed so as to prohibit the movement of the base 10 with respect to the surface plate G.

  As described above, after the object to be measured (workpiece) placed on the table 13 by the motor 21 is slightly rotated, the angle sensor (not shown) makes a predetermined angle in step S105. If detected, in step S106, the drive of the motor 21 is stopped, and in step S107, the electromagnetic valve 12c is turned off for seating, whereby air is applied to the static pressure pads 12b of the three hydrostatic bearings 12. The supply is shut off and the static pressure pad 12b is seated on the base plate 12g.

  In step S108, the detection device S that has received the OFF signal from the solenoid valve 12c, if even one of the three hydrostatic bearings 12 has no electrical continuity between the hydrostatic pad 12b and the base plate 12g, A warning is issued in step S109, assuming that the pressure pad 12b and the base plate 12g are not in contact with each other (not seated yet). As a warning mode, a warning sound such as a display on a host controller or a monitor (not shown) or a buzzer may be considered. On the other hand, if the detection device S detects that the hydrostatic pads 12b of all the hydrostatic bearings 12 are completely seated and are in contact with the base plate 12g, the warning is stopped. Note that when such a state is reached, control may be performed so as to permit movement of the base 10 with respect to the surface plate G.

  According to the present embodiment, the detection device S that detects that the static pressure pad 12b of the static pressure bearing 12 is seated on the base plate 12g is provided. On the other hand, it can be accurately determined whether or not the table 13 is locked.

  In the above control, the detection device S detects only the presence or absence of electrical continuity between the static pressure pad 12b and the base plate 12g, but for example, by measuring the resistance between the two, It is possible to finely discriminate between a state in which all of the three hydrostatic bearings 12 are seated, a state in which at least one hydrostatic bearing 12 is seated, and a state in which all of the three hydrostatic bearings 12 have floated. Accurately grasp.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, the main body 12a of the hydrostatic bearing 12 may be attached to the base 10 side, and the base plate 12g may be attached to the table 13 side.

It is a top view of the positioning table apparatus of this Embodiment. It is sectional drawing which cut | disconnected the structure of FIG. 1 by the II-II line | wire, and looked at the arrow direction. It is a figure which expands and shows the arrow III part of FIG. It is a figure which expands and shows the arrow IV part of FIG. It is the figure which cut | disconnected the structure of FIG. 4 by the VV line and looked at the arrow direction. It is a flowchart figure of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Guide rail 2, 2 Slider 10 Base 11 Base shaft 11a Step part 12 Static pressure bearing 12a Main body 12b Static pressure pad 12c Solenoid valve 12d Supply path 12e Exhaust path 12f Disk-shaped hole 12g Base plate 12h Circumferential groove 12j Spacer 13 Table 13a Central opening 13b Bolt hole 13c Arm 14 Angular contact ball bearing 15 Inner ring spacer 16 Nut 17 Holder 17a End inner peripheral flange 17b End outer flange 18 Fixed member 20 Frame 21 Motor 21a Rotating shaft 22 Coupling 23 Ball screw mechanism 23a Nut 23b Screw shaft 24 Rolling wheel case 25 Rolling wheel 26 Coil spring 27 Adjustment bolt 30 Insulating material B Bolt EC Exhaust connector SC Supply connector

Claims (4)

In the positioning table device that can position the load,
A base with a base shaft attached;
A rotatable table that supports the load; and
A bearing disposed between the base shaft and the table and supporting a radial force of the table;
A hydrostatic bearing disposed on one of the base and the table and supporting an axial force of the table;
A base plate disposed opposite to the hydrostatic bearing on the other of the base and the table;
A detection device for detecting that the hydrostatic bearing is seated on the base plate;
A positioning table device comprising: a driving device that rotates the table relative to the base.   The hydrostatic bearing has a conductive hydrostatic pad, the base plate has electroconductivity, and the detector detects electrical continuity between the hydrostatic pad and the base plate. The positioning table device according to claim 1.   The positioning table device according to claim 1, wherein a conductive film is coated on a surface of the base plate. The positioning table device according to claim 1, wherein the table and a bearing that supports a radial force of the table are connected by a leaf spring.

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