JPH0811336B2 - XY table - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an XY system for mounting a workpiece and moving it on an XY plane.
The present invention relates to a table, and more particularly, to an XY table capable of processing a work piece from both front and back surfaces of the table.

[Prior Art] The automation of various production lines has advanced remarkably in the industrial world in recent years, but the XY table used to send the workpiece to the accurate processing position for various processing machines is
This is an essential element for automating the production line.

Conventionally, as this type of XY table, it is common to place a work piece on a flat plate-shaped table, move it on the XY plane, and perform processing by making a tool approach only from above the table. . However, as machining becomes more complicated and production efficiency increases, it becomes necessary to approach the tool from both the front and back sides of the work piece at the same time, and the XY table that can approach the work piece from the back side of the table as well. Has come to be requested.

In response to this request, as shown in FIG. 9 and FIG. 10, a lower table c which linearly moves in the X direction along a guide b provided on a fixed portion a, and a lower table c on this lower table c are provided. The upper table d, which is placed on the table, moves in the Y direction orthogonal to the lower table c, and moves in a two-dimensional plane when combined with the movement of the lower table c. The upper table d is a frame-shaped table in which the central portion is hollowed out, while the ball screw e for driving the lower table c and the upper table d.
There is known an XY table in which a fixed part a and a lower table c are respectively provided on one side, and a motor f gives a rotational force to the upper part to drive the upper table. Further, as another example, as shown in FIGS. 11 and 12, a support in which an X-direction ball screw h and a Y-direction ball screw i driven by power from a motor g are housed on opposite sides, respectively. Frame j,
A guide shaft 1 which engages with the ball nut k of each of the ball screws h and i and moves in parallel in the X direction or the Y direction between the opposite sides of the support frame j, and guides in the support frame j. An XY table has been proposed which includes a frame-shaped moving table m that is supported by a shaft 1 and that moves in a plane in the X and Y directions.

These two XY tables have a frame shape for the table on which the workpiece is placed, while in a normal XY table, drive means such as a ball screw arranged on the bottom surface of the table is provided on the side of the table. The space below was opened, and it became possible to approach the tool from the back side of the work piece as well as the front side, and it was possible to meet the initial request.

[Problems to be Solved by the Invention] However, the former of the XY tables having the above structure is
As described above, the ball nut of the ball screw, which is the table driving means, is engaged with only one side surface of the table for the convenience of providing the driving means on the side of the table, and is larger when the screw shaft is rotated to drive the table. The structure makes it easy for moment load to act on the ball nut. Therefore, the former XY table has some problems as follows. Firstly, when the direction of movement of the table changes, a larger moment load acts on the table in combination with the inertial force, and it is difficult to obtain highly accurate movement especially when high-speed reciprocating motion is required. The second is that when the actual table load increases due to processing on the work piece, the moment load acting on the ball nut increases extremely and the balls are more likely to wear, resulting in a shorter ball nut life. In addition, the accuracy of table feed and stop deteriorates at an early stage. Further, when the moment load acting on the ball nut is extremely large, the screw shaft may be bent, and when the high speed rotation is applied to the screw shaft, there is a problem that an amplitude is generated in the entire table.

These problems can be solved by means such as increasing the size of the ball nut and the screw shaft to strengthen the rigidity, but on the other hand, there are problems such as an increase in size of the device and an increase in cost. Naturally, it has its limits.

Further, in the latter XY table, since the feed drive system is evenly arranged on both sides of the moving table, the above problems do not occur, but as shown in FIG. There are problems that the transmission path becomes complicated, it takes time to assemble, and the cost increases.

Further, in the former XY table, since the table movement in both the XY directions is obtained by the overlapping structure of the lower table and the upper table, the load on the motor driving the lower table becomes large and the responsiveness to high-speed reciprocating motion deteriorates. In addition, there is a problem that the height of the table cannot be kept low.

The present invention has been made in view of the above problems, and the object of the present invention is not only to approach the workpiece from the space below the table, but also to reduce the load on the feed drive system. You can get high precision movements
To provide an XY table.

[Means for Solving the Problems] In order to achieve the above object, the XY table of the present invention is
A frame-shaped bed having an opening in the center, a frame-shaped moving table having an opening in the center that moves on the bed in the X direction and the Y direction, and rolling grooves of rolling elements along the longitudinal direction of both side surfaces. A pair of downward guide rails that are formed and are attached to the lower surface of the moving table so as to sandwich the opening of the moving table along the X direction, and transfer grooves of the moving body are formed along the longitudinal direction of both side surfaces. As well as
A pair of upward rails mounted on the bed along the Y direction so as to sandwich the opening, and a load that sandwiches a plurality of rolling elements together with the rolling grooves of the downward rail and the upward rail. Four cross linear bearings that have rolling grooves and move along these downward and upward races while applying loads in four directions,
A cross linear bearing that moves along one upward rail and a Y-direction connecting plate that connects the other that moves along the other upward rail to each other, and a pair of cross linear bearings that move along one upward rail. X-direction connecting plate for connecting the two to each other, and one end of the screw shaft is
The cross linear bearing is engaged with the center of the direction connecting plate vertically from the side of the moving table, and the cross linear bearing is moved in accordance with the rotation amount of the ball nut rotatably supported by the bed.
Direction first ball screw, a first motor fixed to the bed to rotate the ball nut of the first ball screw, and one end of the screw shaft of the moving table relative to the center of the X-direction connecting plate. A second ball screw that vertically engages from the side and drives the moving table in the X direction according to the amount of rotation of the ball nut that is rotatably supported by the moving table, and the second ball screw that is fixed to the moving table. And a second motor for rotating the ball nut of the two-ball screw.

In such a technical means, as the cross linear bearing, one bearing block is provided with an X-direction rolling portion that moves along the downward track and a Y-direction rolling portion that moves along the upward track. Type and X
The bearing block having only the directional rolling portion and the bearing block having only the Y directional rolling portion may be changed in design appropriately such as a back-to-back type.

Further, the first ball screw and the second ball screw have such a rigidity that the screw shaft does not deform, such as bend, stretch, and contract, against a tensile force and a pressing force that act in the axial direction when the table is driven. As long as it has the above and the internal clearance in the axial direction between the screw shaft and the ball nut does not affect the processing, the table size and the table driving force required for the processing, etc. Depending on the size and structure, the design may be changed appropriately, but from the viewpoint of preventing back crash due to axial load and obtaining more accurate machining, the balls that are rolling elements have a certain degree of It is preferable that a preload can be applied.

[Operation] The above technical means operates as follows.

When the ball nut of the first ball screw rotatably supported on the bed rotates, the screw shaft screwed to the ball nut pushes and pulls the Y-direction connecting plate, and the cross linear bearing moves along with the moving table along the Y direction. Exercise. On the other hand, when the ball nut of the second ball screw rotatably supported on the moving table rotates, this ball nut is screwed onto the screw shaft fixed to the X-direction connecting plate, so that the moving table is connected in the X-direction. It moves in the X direction with respect to the fixed cross linear bearing of the plate.
As a result, in the present invention, the moving table moves on the bed along the X and Y directions.

At this time, in the present invention, one ends of the screw shafts of the first ball screw and the second ball screw are connected to the Y-direction connecting plate and the X-axis, respectively.
Since it is vertically engaged with the center of the direction connecting plate from the side of the moving table, the space corresponding to the opening of the moving table and the bed is opened, and each ball screw is moved when the moving table moves. Is applied only to the axial force, and no moment load is applied.

[Examples] Hereinafter, the present invention will be specifically described based on Examples shown in the accompanying drawings.

As shown in FIG. 1, the XY table of the present embodiment has a frame-shaped bed 1 on which a two-dimensional moving means is arranged, and a frame-shaped moving body supported by the two-dimensional moving means and movable in both XY directions. A table 2, a first ball screw 3 incorporated in a hollow shaft motor fixed to the bed 1 to drive a two-dimensional moving means in the Y direction by rotation of the motor, and a hollow shaft motor fixed to the moving table 2 in the same manner. And a second ball screw 4 for driving the moving table 2 in the X direction by rotating the motor.

The bed 1 and the moving table 2 are shown in FIGS.
As shown in the figure, it has a frame shape in which the central portion of a substantially flat plate is cut out in a rectangular shape, and when the workpiece is placed so as to straddle the notch portion in the center of the moving table 2, the bed 1 Also, a tool inserted from below the bed through the cutout portion of the moving table 2 can perform a working operation on the lower surface of the workpiece.

The two-dimensional moving means of the moving table 2 is composed of two downward guide rails 5 fixed to the lower surface of the moving table 2 along the X direction with fixing bolts, and a bed 1 arranged below the moving table 2. It is composed of two upward rails 6 fixed along the Y direction with fixing bolts, and cross linear bearings 7 installed at the four intersections of the orthogonal guideways composed of these downward and upward rails 5,6. ing.
As shown in FIGS. 5 and 6, the cross linear bearing 7 is a Y public transfer portion 8 having a plurality of ball rows 21 that roll in the Y direction in a substantially lower half thereof, while a substantially upper half thereof is provided. Half is an X-direction rolling portion 9 provided with a plurality of ball rows that roll along the X-direction, and the Y-direction rolling portion 8 slides on the upward raceway 6 on the bed 1 and also in the X-direction. The rolling section 9 carries the downward track rail 5 on the lower surface of the moving table 2 slidably in the X direction. Therefore, the movable table 2 is movable in the Y direction on the bed 1 together with the cross linear bearing 7, and is movable in the X direction with respect to the cross linear bearing 7, and by combining the two movements, the XY It is possible to move freely in both directions. Reference numerals 10 and 11 denote the first ball screw 3 and the second ball screw 4.
Is a connection plate with which the tips of the screw shafts 31 and 41 engage with each other, and the movements of the screw shafts 31 and 41 and the cross linear bearing 7 are integrated.

Next, the first ball screw 3 and the second ball screw 4 that drive the moving table 2 will be described.

As both of the above, a ball screw of a type in which a ball nut is incorporated in a hollow shaft motor and the motor rotational force is directly transmitted to the ball nut is used. In this ball screw, as shown in FIG. 7, a ball nut 12 is rotatably supported by a motor housing 13, and a rotor core 14
When a rotational force is generated on the stator core 15, the rotor core
The ball nut 12 rotates following 14 and the screw shaft 31 or 41 fitted to this inner peripheral surface via the ball 16 is a ball nut.
The motor housing 13 is driven back and forth in accordance with the rotation amount of 12. Then, in this embodiment, the ball screw having the above structure is fixed to the center of the end of the bed 1 in the Y direction so that the screw shaft 31 extends along the Y direction to form the first ball screw 3 (see FIG. 4). The second ball screw 4 is formed by fixing the screw shaft 41 at the center of the end of the moving table 2 in the X direction so that the screw shaft 41 extends along the X direction (see FIG. 3). In addition, the tips of the respective screw shafts 31 and 41 are attached to the flange 18 by a pin 17 that penetrates perpendicularly to the axial direction.
On the other hand, the flange 18 is fixed to the center of the connecting plate 10 or 11 by a fixing bolt 19, and is movable in the Y direction together with the cross linear bearing 7 in a state where both screw shafts 31 and 41 are not rotated. Has become. Reference numeral 20 is a bracket for mounting the motor housing 13 on the bed 1 or the moving table 2.

Next, the basic operation of this XY table will be described.

The ball nuts 12 of the ball screws 3 and 4 are supported by the bed 1 or the moving table 2 via the motor housing 13, so that when an electric signal is applied to each hollow shaft motor and the ball nuts 12 rotate, The screw shafts 31 and 41 are displaced relative to the bed 1 or the moving table 2. At this time, since the connecting plate 10 with which the tip of the screw shaft 31 of the first ball screw 3 is engaged can move in the Y direction which is the same as the traveling direction of the screw shaft 31, the screw shaft 31 is displaced relative to the bed 1. When this occurs, this displacement appears as a Y-direction displacement of the cross linear bearing 7, that is, a Y-direction displacement of the moving table 2 with respect to the bed 1. The connecting plate 11 with which the tip of the screw shaft 41 of the second ball screw 4 is engaged is integrated with the cross linear bearing 7 and is movable in the Y direction, but in the X direction which is the traveling direction of the screw shaft 41. Therefore, when the screw shaft 41 is displaced with respect to the movable tebule 2, this displacement appears as a displacement in the X direction with respect to the cross linear bearing 7 of the movable table 2, that is, a displacement in the X direction with respect to the bed 1. Therefore, by applying a command signal based on the required amount of movement of the moving table 2 to each hollow shaft motor and controlling the amount of rotation of the ball nut 12, the above-mentioned movements in the X direction and the Y direction are combined and the movement is performed. The table 2 moves to an arbitrary position and functions as an XY table.

Due to the structure of the XY table of this embodiment, the driving force for driving the moving table 2 acts mainly between the ball screws 3 and 4 and the moving table 2 as a compressive load or a tensile load in the axial direction. No large moment load acts on the moving table 2 or the ball screws 3 and 4.

Therefore, the sliding of the moving table 2 is stable, and highly accurate table movement can be obtained.

In addition, in the present embodiment, since the moving table 2 is guided in both the XY directions by using the cross linear bearings 7 without using the table overlapping structure such as the lower table and the upper table, the first ball screw 3 is driven. The weight of the table is reduced, the inertial force acting on the moving table 2 is reduced, the accuracy of feeding and stopping is improved, and the speed is increased.

Second Embodiment The XY table in this embodiment is composed of a ball screw 22 whose feed drive system is rotatably supported by the bed 1 or the moving table 2 and a motor 23 arranged in parallel with the ball screw 22. Except for this, it is substantially the same as the XY table according to the first embodiment.

As shown in FIG. 6, the ball screw 22 is provided with an outer ring member 26 on the outer peripheral surface of a ball nut 24 via a ball 25, and the outer ring member is mounted on a bed 1 or a moving table 2 via a bracket 27. By fixing, the ball nut 24 is rotatably supported with respect to the bed 1 or the moving table 2. Further, a pulley 28 is provided at the axial end of the ball nut 24, and rotational power is provided by a timing belt 29 stretched between the ball screw 22 and a motor 23 fixed to a bracket 27 in parallel with the ball screw 22. To be given.

In the XY table of this embodiment having the above structure,
When a command signal from the control device is given to the motor 23, the rotational force is transmitted to the ball nut 24 by the timing belt 29 and the ball nut 24 is rotated, and the bed where the screw shafts 31 and 41 and the ball nut 24 are supported. 1 or relative movement occurs between the movable table 2 and the movable table 2, and the movable table 2 is driven by the same structure as in the first embodiment.

Therefore, also in the XY table of this embodiment, sliding of the movable table 2 is stable and highly accurate table movement can be obtained, as in the first embodiment.

In this embodiment, the timing belt 29 is used as a means for transmitting the rotational power of the motor 23 to the ball nut 24.
Although the pulley 28 is used, the same effect can be obtained as the power transmission means if the rotation amount of the motor 23 is accurately transmitted to the ball nut 24, such as a chain, a gear or a gear train. It is possible.

[Advantages of the Invention] As described above, according to the XY table of the present invention, the space corresponding to the opening of the moving table and the bed is opened, and the moment load is applied to each ball screw during the movement of the moving table. Does not work, problems such as deterioration of movement accuracy of the moving table and complication of structure are solved, and highly accurate table movement can be obtained with a simple structure.

Further, in the first ball screw and the second ball screw, the table is driven by rotating the ball nut while fixing the screw shaft, so that it is not necessary to consider the critical speed due to the rotation of the shaft, so The rotation speed can be increased as compared with the feed by the shaft rotation, and the feed speed of the moving table can be increased accordingly.

[Brief description of drawings]

FIG. 1 shows a first embodiment of an XY table according to the present invention, and is a schematic perspective view showing a part of it as a perspective view. FIG. 2 is a plan view of an XY table according to the first embodiment, and FIG. Is the second
Fig. 4 is a sectional view taken along the line AA in Fig. 4, Fig. 4 is a sectional view taken along the line BB in Fig. 2, Fig. 5 is a side view showing a cross linear bearing which is a two-dimensional moving means of the moving table, and Fig. 6 is Fig. 5. CC sectional view of FIG. 7, FIG. 7 is a perspective view showing the outline of the hollow shaft motor according to the first embodiment, FIG. 8 is a sectional view showing the outline of the ball screw according to the second embodiment, FIG. 9 and FIG. 10 is a schematic plan view showing an example of a conventional XY table and a schematic view schematically showing the driving unit, and FIGS. 11 and 12 are also schematic plan views showing an example of a conventional XY table and its driving. It is the schematic diagram which represented the part simply. [Explanation of symbols] 1: Head 2: Moving table 3: First ball screw 4: Second ball screw 5: Down track way 6: Up track way 7: Cross linear bearing 10, 11: Connection plate 12: Ball nut 31 , 41: Screw shaft

Claims (3)

[Claims] 1. A frame-shaped bed having an opening in the center, a frame-shaped moving table having an opening in the center that moves on the bed in the X and Y directions, and rolling elements along the longitudinal direction of both side surfaces. And a pair of downward track rails attached to the lower surface of the movable table along the X direction and so as to sandwich the opening of the movable table, and a movable body along the longitudinal direction of both side surfaces. And a pair of upward rails mounted on the bed along the Y direction so as to sandwich the opening, and the rolling grooves of the downward rail and the upward rail. Having a rolling groove for sandwiching a plurality of rolling elements, and four cross linear bearings that move along these downward and upward races while applying loads in four directions, Crossing linear bearing that moves along one upward rail, and a Y-direction connecting plate that connects the other crossing linear bearing that moves along another upward rail, and a pair of cross linear bearings that move along one upward rail. Rotation of a ball nut rotatably supported by the bed, with an X-direction connection plate connecting the two with each other, and one end of a screw shaft vertically engaged with the center of the Y-direction connection plate from the side of the moving table. A first ball screw that drives the cross linear bearing in the Y direction according to the amount; a first motor that is fixed to the bed and that rotates the ball nut of the first ball screw; and one end of the screw shaft that is connected in the X direction. Depending on the amount of rotation of the ball nut that is vertically engaged with the center of the plate from the side of the moving table and is rotatably supported by the moving table. XY table, wherein a second ball screw for driving the moving table in the X direction, that is fixed to the moving table is composed of a second motor for rotating the ball nut of the second ball screw. 2. A ball screw, wherein at least one of the first ball screw and the second ball screw has a ball nut that is incorporated in a hollow shaft motor and that rotates following a core in the motor. The XY table according to claim 1, which is characterized in that 3. A ball screw having a ball nut with a support bearing in which at least one of a first ball screw and a second ball screw has an outer ring with a ball interposed on the outer peripheral surface of the nut. The XY table according to claim 1, wherein the ball nut is rotatably supported by engaging with a bed or a moving table, and the rotation of the motor is transmitted to the nut to rotate the nut.