JPH09184517A - Xy table with linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a moving part and secure correct positioning accuracy with excellent responsiveness for starting and stopping by lowering the height of an XY table. SOLUTION: An intermediate saddle 2 is attached slidably in an X shaft direction on a base mount 1 through a first linear guide device 4, and also a table main body 3 is attached slidably in a Y shaft direction on the intermediate saddle 2 through a second linear guide device 5. A first linear motor 11 by which the intermediate saddle 2 is driven in the X shaft direction and a second linear motor 16 by which the table main body 3 is driven in the Y shaft direction are arranged. The stator 12 of the first linear motor 11 is arranged in the X shaft direction on the upper surface of the base mount 1, and also the stator 17 of the second linear motor 16 is arranged in the Y shaft direction on the lower surface of the table main body 3, and further, the movers 13, 18 of the first and second linear motors 11, 16 are arranged in the dead space of the intermediate saddle 2 by being perpendicular to each other and faced in opposite directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an XY table with a linear motor, and more particularly to a thin XY table using a linear motor as a drive unit.

[0002]

2. Description of the Related Art XY tables are widely used in measuring devices, inspection devices, semiconductor manufacturing devices and the like. In a conventional XY table, a table body attached to a base via an intermediate saddle is configured to be slidable in X-axis and Y-axis directions orthogonal to each other, and its feed mechanism is a ball screw and A rotary motor such as a servo motor or a stepping motor is combined and configured.

That is, a rotatable screw shaft is arranged in the X-axis direction on the upper part of the base, and a nut screwed to the screw shaft is fixed to the intermediate saddle and connected to the end of the screw shaft. Due to the rotation of the rotary motor, the intermediate saddle moves in the X-axis direction along the screw shaft. Further, similarly, the screw shaft of the ball screw is arranged in the Y-axis direction orthogonal to the screw shaft above the intermediate saddle, and the nut screwed to the screw shaft is fixed to the lower portion of the table main body. The table body is transferred to the intermediate saddle in the Y-axis direction by the rotation of the rotary motor connected to the table.

In the above-mentioned conventional structure, the X-axis of the table main body is controlled by controlling the rotation of the rotary motor.
Although the transfer in the Y-axis direction is controlled, the inertial force of the moving part is large because the drive device such as the rotation motor and the ball screw are mounted, and the responsiveness at the time of starting and stopping deteriorates and positioning is performed. There was a problem that the accuracy deteriorated.

In order to solve this problem, Japanese Patent Publication No. 4-26970 proposes an XY table in which a linear motor is used to reduce the inertial force of the moving part to improve the responsiveness. In the XY table disclosed in Japanese Examined Patent Publication No. 4-26970, an intermediate saddle is movably attached to the base via a first linear guide device in the X-axis direction, and a second straight line is attached to the intermediate saddle. A table body is slidably mounted in a Y-axis direction orthogonal to the X-axis through a guide device, a linear motor including a stator and a mover is interposed between the intermediate saddle and the base, and the intermediate saddle is further provided. A linear motor composed of a stator and a mover is interposed between the table and the table body.

[0006]

However, in the above-described XY table driven by a linear motor, a linear motor including a stator disposed on the upper surface of the base and a movable element disposed on the lower surface of the intermediate saddle is interposed. Further, a linear motor including a stator arranged on the lower surface of the table body and a mover arranged on the upper surface of the intermediate saddle is interposed. That is, since the two linear motors are stacked, the vertical height of the XY table is high, and the weight of the moving part is large, so the inertial force is large and, in the end, the responsiveness at the time of starting and stopping. However, there was a problem in that the positioning accuracy could not be ensured because it could not be improved so much.

The present invention has been made in view of the above circumstances, and the height of the XY table is low, the weight of the moving portion can be reduced, the response of starting and stopping is good, and the accurate positioning accuracy can be secured. It is an object to provide an XY table with a motor.

[0008]

In order to achieve the above-mentioned object, according to the present invention, an intermediate saddle is slidably attached in the X-axis direction to a base via a first linear guide device, and
A table main body is slidably attached to the intermediate saddle via a second linear guide in the Y-axis direction orthogonal to the X-axis, and a first linear motor for driving the intermediate saddle in the X-axis direction and the first linear motor are provided. In an XY table with a linear motor provided with a second linear motor for driving the table body in the Y-axis direction, ball rolling grooves are formed on both side surfaces of the base, and the first linear motor is fixed on the upper surface. Children are arranged in the X-axis direction, ball rolling grooves are formed on both side surfaces of the table body, and stators of the second linear motor are arranged in the Y-axis direction on the lower surface, and the intermediate saddle is rectangular. A flat plate portion and upper and lower reinforcing portions formed by projecting from both sides of the upper surface and the lower surface of the flat plate portion in different directions so as to be orthogonal to each other are formed. Second linear motor available The children are arranged orthogonally to each other and are arranged back to back, and ball rolling grooves facing the ball rolling grooves on both side surfaces of the base are formed on the inner surface of the lower reinforcing portion, and the ball rolling grooves are formed. The escape ball raceway is provided at a position distant from, and a communication passage communicating with the ball rolling groove and the escape ball raceway is provided, and the inside of the endless track formed by the ball rolling groove, the communication passage and the escape ball raceway is provided. A plurality of balls are circulated to form the first linear guide device, ball rolling grooves are formed on the inner side surface of the upper reinforcing portion so as to face the ball rolling grooves on both side surfaces of the table body, and The escape ball raceway is provided at a position distant from the ball rolling groove, and the communication passage communicating the ball rolling groove and the escape ball raceway is provided, and the ball rolling groove, the communication passage and the escape ball raceway are formed. In the endless orbit It is characterized in that constitute the second linear guide unit by circulating the number of balls.

According to the present invention, the stator of the first linear motor is arranged on the upper surface of the base in the X-axis direction, and the stator of the second linear motor is arranged on the lower surface of the table body in the Y-axis direction. The intermediate saddle is composed of a rectangular flat plate portion and upper and lower reinforcing portions, and the movers of the first and second linear motors are arranged orthogonally to each other in the central space of the flat plate portion and are arranged back to back. ing. That is, using the void in the middle saddle
Also, since the movers of the second linear motor are arranged back to back, a structure in which two linear motors are stacked can be avoided, and a thin X-type having a low vertical height.
A Y table can be constructed. Further, the upper and lower reinforcing portions of the intermediate saddle are used to form a first linear guide device and a second linear guide device.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An XY table with a linear motor according to the present invention will be described below with reference to the embodiments shown in the accompanying drawings. FIG.
FIG. 2 is a plan view showing an embodiment of an XY table with a linear motor according to the present invention, and FIG. 2 is a II of FIG. 1 having a partial cross section.
It is an arrow view. In FIGS. 1 and 2, reference numeral 1 is a base, and the base 1 has a table body 3 via an intermediate saddle 2.
Is attached.

The base 1 is sandwiched by the first linear guides 4 and 4 provided on the lower surface of the intermediate saddle 2 and arranged in parallel, and the table body 3 is provided on the upper surface of the intermediate saddle 2 and arranged in parallel. It is sandwiched by the second linear guide devices 5 and 5. When the longitudinal direction of the base 1 is the X axis and the direction parallel to the upper surface of the base 1 and orthogonal to the X axis is the Y axis, the intermediate saddle 2 is slidable in the X axis direction by the linear guide devices 4 and 4. The table body 5 is a linear guide device 5, 5
Is slidable in the Y-axis direction.

The base and the table body 3 are made of rectangular flat plate members having a predetermined length, and ball rolling grooves 1a are formed on both side surfaces of the base 1 in the longitudinal direction.
Ball rolling grooves 3a are formed on both side surfaces in the longitudinal direction.

FIG. 3 is a perspective view showing the intermediate saddle 2.
As shown in FIG. 3, the intermediate saddle 2 has a rectangular flat plate portion 2a.
And lower reinforcing portions 2b, 2b formed so as to project downward from both side portions of the flat plate portion 2a, and upper reinforcing portions 2c, 2c formed so as to project upward from both side portions of the flat plate portion 2a. There is. The lower reinforcing portions 2b, 2b and the upper reinforcing portion 2c,
2c are formed so as to be orthogonal to each other, and a hollow space 2d is formed at the center of the flat plate portion 2a.

Ball rolling grooves 2e, 2e are formed on the inner surfaces of the lower reinforcing portions 2b, 2b.
Recessed grooves 2f, 2f are formed at positions on the opposite side separated from 2e. Then, each concave groove 2f has a cylindrical pipe 7
Are fitted together, and an escape ball orbit is formed by the cylindrical pipe 7. A side lid 8 is fixed to the lower reinforcing portions 2b and 2b, and a communication passage 8a in the side lid 8 connects the ball rolling groove 2e and the pipe 7 which is the escape ball raceway. ing. That is, an endless track formed of the ball rolling groove 2e, the communication path 8a of the side lid 8 and the pipe 7 which is the escape ball track is provided in the lower reinforcing portion 2b.
A large number of balls 9 are circulated in this endless track to form the linear guide device 4.

4 and 5 are views showing the relationship between the linear guide device 4 and the base 1, FIG. 4 is a plan view having a partial cross section, and FIG. 5 is a cross sectional view taken along line VV of FIG. As shown in FIGS. 4 and 5, the rolling surfaces of the ball transfer grooves 1a and 2e are circular grooves formed in a curved surface with a radius of curvature slightly larger than the radius of the ball 9, and the transfer grooves 1a and 2e are The ball 9 has only one contact surface for contact rolling. The contact line connecting the ball 9 and the contact points of the rolling grooves 1a and 2e facing each other is located on the horizontal line.

As shown in FIG. 3, the upper reinforcing portion 2c,
Ball rolling grooves 2g, 2g are formed on the inner surface of 2c,
Recessed grooves 2h, 2h are formed at positions on the opposite side away from the ball rolling grooves 2g, 2g. A cylindrical pipe 7 is fitted into the groove 2h, and the cylindrical pipe 7 forms an escape ball orbit. The side cover 8 is fixed to the upper reinforcing portion 2c, and the ball rolling groove 2g and the pipe 7 which is the escape ball raceway are communicated with each other by the communication passage 8a in the side cover 8. . That is,
The endless track formed of the ball rolling groove 2g, the communication path 8a of the side cover 8 and the pipe 7 which is the escape ball track is connected to the upper reinforcing portion 2
A large number of balls 9 are circulated in this endless track to form the linear guide device 5. The relationship between the linear guide device 5 and the table body 3 is substantially the same as the relationship between the linear guide device 4 and the base 1 shown in FIGS.

As described above, in this embodiment, since the long intermediate saddle 2 is used, the intermediate saddle 2 is used.
Forming long escape ball holes in the upper and lower reinforcing portions 2b and 2c is not easy to process. Therefore, concave grooves 2f and 2h are formed on both side surfaces of the upper and lower reinforcing portions 2b and 2c, a pipe 7 is fitted into the concave grooves 2f and 2h, and the escape ball path is formed by the pipe 7. by this,
We are working to reduce processing costs.

Further, as shown in FIG. 2, the first saddle 2 for driving the intermediate saddle 2 in the X-axis direction is provided between the intermediate saddle 2 and the base 1.
The linear motor 11 is arranged, and the second linear motor 16 for driving the table body 3 in the Y-axis direction is arranged between the intermediate saddle 2 and the table body 3. The first and second linear motors 11 and 16 are linear pulse motors in the present embodiment, each of which is composed of a combination of a mover and a stator, and from a pulse source (not shown) to a mover. It operates by inputting a pulse. That is, the stator 12 of the first linear motor 11 is arranged in the X-axis direction on the upper surface of the base 1, and the stator 17 of the second linear motor 16 is arranged on the lower surface of the table main body 3 in the Y-axis direction. Are arranged in the direction. Each of the stators 12 and 17 is composed of a flat plate member made of a magnetic material.

On the other hand, a support plate 22 fixed to the intermediate saddle 2 is arranged in a central space 2d formed in the flat plate portion 2a of the intermediate saddle 2. The mover 13 of the first linear motor 11 and the mover 18 of the second linear motor 16 are fixed to the support plate 22 so as to be orthogonal to each other and back-to-back. As a result, the mover 13 faces the stator 12, and the mover 18 faces the stator 17.

FIG. 6 is a view showing the detailed structure of the first linear motor 11. As shown in FIG. 6, the mover 13 of the first linear motor 11 is configured by interposing a permanent magnet 13a in the center and arranging two magnetic cores on the left and right sides thereof so as to face each other. Is a first magnetic pole 13b and a second magnetic pole 13c magnetized to the N pole by the permanent magnet 13a.
And the third magnetic pole 13d and the fourth magnetic pole 1 magnetized to the S pole by the permanent magnet 13a are formed on the other magnetic core.
3e is formed.

On the stator 12 of the first linear motor 11, fixed teeth 14 having a U-shaped cross section extending across the X axis as shown in FIG. 6 are provided at the same pitch P over the substantially entire length in the X axis direction. It is provided at intervals. Each magnetic pole 13b, 13
Magnetic pole teeth having the same pitch as that of the stator 12 are also formed on c, 13d, and 13e. The first magnetic pole 13b and the second magnetic pole 13c on the N pole side have a first coil 15a and a second magnetic pole 13c.
The coil 15b is wound and is connected in series so that magnetic fluxes in opposite directions are generated when a current flows, and is electrically connected to a pulse generation source (not shown). On the other hand, similarly to the third magnetic pole 13d and the fourth magnetic pole 13e on the S pole side, the third coil 15 connected in series is also used.
c and the fourth coil 15d are wound and connected to the pulse generation source.

FIG. 7 is a diagram showing a detailed structure of the second linear motor 16. As shown in FIG. 7, the mover 18 of the second linear motor 16 is configured by interposing a permanent magnet 18a in the center and disposing two magnetic cores on the left and right sides of the permanent magnet 18a so as to face each other. Is a first magnetic pole 18b and a second magnetic pole 18c magnetized to the N pole by the permanent magnet 18a.
Is formed, and the third magnetic pole 18d and the fourth magnetic pole 1 magnetized to the S pole by the permanent magnet 18a are formed on the other magnetic core.
8e are formed.

On the stator 17 of the second linear motor 16, fixed teeth 19 having a U-shaped cross section extending across the Y axis are provided at the same pitch P over the entire length in the Y axis direction as shown in FIG. It is provided at intervals. Each magnetic pole 18b, 18
Magnetic pole teeth having the same pitch as that of the stator 17 are also formed on c, 18d, and 18e. The first magnetic pole 18b and the second magnetic pole 18c on the N pole side are provided with a first coil 20a and a second coil 20a.
The coil 20b is wound and connected in series so as to generate mutually opposite magnetic flux when a current flows, and is electrically connected to a pulse generation source (not shown). On the other hand, similarly to the third magnetic pole 18d and the fourth magnetic pole 18e on the S pole side, the third coil 20 connected in series is also used.
c and the fourth coil 20d are wound and connected to the pulse generation source.

Since the operating principles of the first linear motor 11 and the second linear motor 16 configured as described above are well known, description thereof will be omitted.

As described above, in this embodiment, the base 1
The stators 12 of the first linear motor 11 are arranged in the X-axis direction on the upper surface of the table, and the stators 17 of the second linear motor 16 are arranged in the Y-axis direction on the lower surface of the table body 3, and the intermediate saddle 2 is rectangular. Shaped flat plate portion 2a and upper and lower reinforcing portions 2b, 2
In the central space 2d, the movers 13 and 18 of the first and second linear motors 11 and 16 are orthogonal to each other and are arranged back to back.

That is, by utilizing the space 2d of the intermediate saddle 2, the movers 13 of the first and second linear motors 11 and 16,
Since 18 is arranged back to back, a structure in which two linear motors are stacked can be avoided, and a thin XY table having a low vertical height can be configured.

Further, in the present embodiment, the intermediate saddle 2
Is a rectangular flat plate portion 2a, and upper and lower part reinforcing portions 2b formed in different vertical directions from both sides of the flat plate portion 2a,
2c and. The upper and lower reinforcing portions 2b and 2c are important for increasing the rigidity of the intermediate saddle 2, and this point will be described in detail below. (1) Necessity of rigidity of the intermediate saddle The intermediate saddle 2 is linearly guided by the linear guide devices 4 and 4 for linearly guiding the intermediate saddle 2 with respect to the base 1, and the table main body 3 is linearly guided with respect to the intermediate saddle 2. Linear guide devices 5 and 5 are provided. Linear guide devices 4, 4 and 5, which are arranged in parallel
It is extremely important for the table bodies 3 not to come close to or apart from each other so that the table body 3 can slide accurately in the X and Y directions. (2) Rigidity of Intermediate Saddle With reference to a representative example of the force acting on the intermediate saddle 2, the rigidity of the intermediate saddle 2 having the above configuration will be described below from a mechanical point of view. (I) Typical force acting The force acting on the intermediate saddle due to the weight of the load The force due to the load is generated by being mounted on the table top surface. The direction is the radial direction from the top to the bottom. This radial load is transmitted to the ball rolling groove of the upper reinforcing portion via a large number of balls. In the case of this embodiment, this force is transmitted by the balls 9 located in the ball rolling groove 2g of the upper reinforcing portion 2c, and its direction is
It is horizontal. The force to open the upper reinforcing portion 2c to the outside is
This is the horizontal direction. Force due to preload of ball Preload is applied to the ball to maintain the rigidity of the entire device. The direction is determined by the number of bearing grooves and the contact structure. In the case of this embodiment, one ball 9
A preload is applied to the contact angle, and the contact angle is in the horizontal direction. The force for opening the upper and lower reinforcing portions 2b and 2c outward is in the horizontal direction of the contact angle direction. Inertial force due to reciprocating acceleration Due to the mass of the load, a bending moment is applied to the intermediate saddle due to the reciprocating acceleration of the table. This bending moment is applied to the ball groove of the intermediate saddle in the radial direction from the upper side to the lower side and the force in the reverse radial direction from the lower side to the upper side with the horizontal center portion of the intermediate saddle as a boundary. (Ii) Rigidity of upper and lower reinforcing portions As shown in FIG. 8A, the upper and lower reinforcing portions 2b and 2c are considered to be a cantilever structure, and the connecting portion between the flat plate portion 2a and the upper and lower reinforcing portions 2b and 2c is a beam. Assuming that the positions of the fixed portion and the ball rolling grooves 2e and 2g are the points of action of the horizontal component force, the upper and lower reinforcing portions 2
The displacement δ ₁ of b and 2c is inversely proportional to the geometrical moment of inertia I ₁ of the cross section S of the fixed portion. (Iii) Rigidity of horizontal flat plate upper and lower reinforcing portions 2b. The base of 2c is connected to the integral structure by a horizontal flat plate 2a. Upper and lower reinforcement parts 2b, 2c
The force to open the plate acts as a bending moment M on both sides of the horizontal flat plate portion 2a as shown in FIG. 8 (b). With respect to this bending moment M, the larger the secondary moment of inertia I _{2 of the} AA cross section, the more rigid it is without being displaced by the above two forces. Like the upper part, the lower part of the horizontal flat plate part 2a has lower reinforcing parts 2 at both ends thereof.
b is formed. FIG. 8C is A-A of FIG. 8B.
It is a cross section. As shown in FIG. 8C, the hanging portion of the intermediate saddle 2 is the lower reinforcing portions 2b and 2b. As a result, the intermediate saddle 2 has a groove shape of the structural material, and since the intermediate saddle 2 has both rib portions including the lower reinforcing portions 2b and 2b, the intermediate saddle 2 is not displaced with respect to the bending moment M and has rigidity. There will be. (IV) Relation of force from intermediate saddle to lower base This is the same as the relation of force action and direction in upper table body and intermediate saddle, and displacement and rigidity. (V) Inertial force due to reciprocating acceleration This is the same as the force due to the mounting force and the preload.

As described above, the intermediate saddle 2 of this embodiment is integrally provided with the lower reinforcing portion 2b and the upper reinforcing portion 2c which are different in direction from each other on the upper and lower sides of the flat plate portion 2a. The rigidity of 2 is extremely high.

[0029]

As described above, according to the present invention, the movable elements of the first and second linear motors are arranged back-to-back using the empty space of the intermediate saddle, so that the height of the XY table is increased. Can be lowered, and the weight of the moving part can be reduced. Therefore, it is possible to provide an XY table having a good start-stop response and good positioning accuracy.

Further, according to the present invention, since the intermediate saddle is composed of the flat plate portion and the upper and lower reinforcing portions which are formed to project from both sides of the upper surface and the lower surface of the flat plate in different directions and are orthogonal to each other, the intermediate saddle is formed. The saddle rigidity can be secured, and X
It is possible to secure the movement accuracy and the positioning accuracy of the Y table.

Further, according to the present invention, by using the pipe for the escape ball trajectory of the linear guide device, it is not necessary to form a long escape ball hole, and the processing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of an XY table with a linear motor according to the present invention.

FIG. 2 is a view taken in the direction of arrow II in FIG. 1 having a partial cross section.

FIG. 3 is a perspective view of an intermediate saddle in an XY table with a linear motor according to the present invention.

FIG. 4 is a plan view showing the relationship between the intermediate saddle, the first linear guide device, and the base in the XY table with a linear motor according to the present invention.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a sectional view showing a detailed structure of a first linear motor in an XY table with a linear motor according to the present invention.

FIG. 7 is a sectional view showing a detailed structure of a second linear motor in an XY table with a linear motor according to the present invention.

FIG. 8 is an explanatory diagram illustrating the rigidity of the intermediate saddle in the XY table with a linear motor according to the present invention.

[Explanation of symbols]

 1 Base 2 Intermediate Saddle 2a Flat Plate 2b Lower Reinforcement 2c Upper Reinforcement 3 Table Main Body 4,5 Linear Guide 7 Pipe 8 Side Lid 9 Load Ball 11 First Linear Motor 12 Stator 13 Mover 14 Fixed Teeth 15 Coil 16 Second linear motor 17 Stator 18 Mover 19 Fixed tooth 20 Coil 22 Support plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B23Q 1/18 A

Claims (2)

[Claims] 1. An intermediate saddle is slidably attached to a base in the X-axis direction via a first linear guide device, and a table body is attached to the intermediate saddle via a second linear guide device. A linear unit that is slidably mounted in the Y-axis direction orthogonal to the axis and that includes a first linear motor that drives the intermediate saddle in the X-axis direction and a second linear motor that drives the table body in the Y-axis direction. In an XY table with a motor, ball rolling grooves are formed on both side surfaces of the base, and the stator of the first linear motor is arranged on the upper surface in the X-axis direction, and ball rolling is performed on both side surfaces of the table body. Grooves are formed and stators of the second linear motor are arranged on the lower surface in the Y-axis direction. The intermediate saddle is a rectangular flat plate portion, and the direction is changed from both sides of the upper and lower surfaces of the flat plate portion. Projecting to each other An upper and a lower reinforcing portion formed orthogonally to each other, and arranging the movers of the first and second linear motors in a central space of the flat plate portion so as to be orthogonal to each other, and arranged back to back, Ball rolling grooves facing the ball rolling grooves on both sides of the base are formed on the inner surface of the lower reinforcing portion, and escape ball raceways are provided at positions separated from the ball rolling grooves and the ball rolling grooves are provided. A communication passage that connects the running groove and the escape ball raceway is provided, and a large number of balls are circulated in an endless track formed by the ball rolling groove, the communication passage and the escape ball raceway to provide the first linear guide device. A ball rolling groove is formed on the inner surface of the upper reinforcing portion, the ball rolling groove being opposed to the ball rolling grooves on both side surfaces of the table body, and the escape ball raceway is provided at a position separated from the ball rolling groove. With the ball rolling groove and escape The second linear guide device is configured by circulating a large number of balls in an endless track formed of the ball rolling groove, the communication path and the escape ball track path. Characteristic XY table with linear motor. 2. The escape ball raceways in the first straight guide device and the second straight guide device are constituted by a cylindrical pipe held by the upper and lower reinforcing portions. An XY table with a linear motor according to 1.