JP4697658B2 - Positioning table device - Google Patents

Description

  The present invention relates to a positioning table device, for example, a positioning table device capable of positioning a heavy object and positioning at a minute 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, when hydrostatic bearings are used, the fluid that generates static pressure must be supplied from the outside, so piping is complicated especially when supporting hydrostatic bearings in the radial and thrust directions. There is a problem. On the other hand, there is an idea that the rotating body is supported in a radial direction and a thrust direction by using a cross roller bearing with respect to the fixed body, but the cross roller bearing has a small load capacity for its size, so When supporting a heavy load of 100 kg or more including the measurement object, a large cross roller bearing must be used, and there is a problem that the entire apparatus becomes large. There is also a problem in that starting torque increases when preload is applied to the cross roller bearing to eliminate backlash.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a positioning table device capable of finely rotating a heavy object while being compact in view of the problems of the prior art.

In order to achieve the above-described object, the positioning table device of the present invention is a positioning table device capable of placing a heavy object and positioning it at a minute angle.
A base with a base shaft attached;
A rotatable table that supports heavy objects;
A contact-type bearing disposed between the base shaft and the table and supporting a radial force of the table;
A non-contact bearing disposed between the base and the table and supporting an axial force of the table;
Possess a driving device for finely moving rotating the table relative to the base,
The non-contact type bearing is a hydrostatic bearing provided with a hydrostatic pad,
The table is movable in the axial direction, and is seated on the hydrostatic pad when rotating and stationary.
The contact-type bearing is a rolling bearing, and the rolling bearing and the table are connected via an elastic member .

  According to the positioning table device of the present invention, the relatively small radial force received by the table can be supported by a contact bearing having a low capacity (such as a rolling bearing or a sliding bearing), and thus the size of the bearing can be reduced. This makes it possible to reduce the weight and size of the positioning table device. On the other hand, the relatively large axial force received by the table can be supported by a non-contact bearing. The “small angle” means ± 1 °.

  Further, the non-contact type bearing is preferably a hydrostatic bearing provided with a hydrostatic pad, but may be a magnetic bearing.

  Further, the table is movable in the axial direction, and when the table is seated on the static pressure pad during rotation and stationary, the stationary table is prevented from rotating due to vibration or the like due to friction generated therebetween.

  Furthermore, when the rolling bearing and the table are connected via an elastic member, the table can be easily moved in the axial direction in order to be seated on the static pressure pad, for example.

  Furthermore, the static pressure bearing can increase the holding force of the table seated on the static pressure pad when the table is adsorbed when the rotary bearing is stationary.

  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. 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 and 14 need only receive 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 disc-like base plate 12g made of hard metal such as ceramic or SUS440C is fixed on the base 10 with bolts B. 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 the measurement object (not shown) placed on the table 13, the table 13 is moved to the inspection position. Next, 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.

  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 air can be sucked from the static pressure pad 12b to obtain an adsorption force with the base plate 12g, 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.

  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.

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 Bearing 23b Screw shaft 24 Rolling wheel case 25 Rolling wheel 26 Coil spring 27 Adjustment bolt B Bolt EC Exhaust connector SC Supply connector

Claims (2)

In a positioning table device that can place a heavy object and position it at a minute angle,
A base with a base shaft attached;
A rotatable table that supports heavy objects;
A contact-type bearing disposed between the base shaft and the table and supporting a radial force of the table;
A non-contact bearing disposed between the base and the table and supporting an axial force of the table;
Possess a driving device for finely moving rotating the table relative to the base,
The non-contact type bearing is a hydrostatic bearing provided with a hydrostatic pad,
The table is movable in the axial direction, and is seated on the hydrostatic pad when rotating and stationary.
The contact type bearing is a rolling bearing, and the rolling bearing and the table are connected via an elastic member . The positioning table device according to claim 1 , wherein the static pressure bearing attracts the table when the rotary bearing is stationary.

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