JP4702825B2 - Stage device and machine tool - Google Patents

Description

  The present invention relates to a stage apparatus and a machine tool, and more particularly to a stage apparatus and a machine tool including a linear motor.

  2. Description of the Related Art Conventionally, various machines including a stage device such as a machine tool or a semiconductor processing apparatus have a structure including a linear motor (see, for example, Patent Document 1). Linear motors are propelled linearly in a floating state by a magnetic field generated by a magnet, and since there is no friction, there is no problem of wear of machine parts, and high positioning accuracy is continued. There is an advantage that it can be maintained.

  However, since a large current is normally supplied to the coil for driving the linear motor, there is a disadvantage that heat generated due to the resistance of the coil is generated by the supplied current. If excessive heat is generated in the linear motor, a mechanical component arranged around the linear motor, for example, the work stage itself may be thermally deformed, resulting in a disadvantage that the positioning accuracy and the processing accuracy of the component are lowered.

  In order to solve this, in Patent Document 1, a cooling fluid flow path is provided in a coil housing that constitutes a slider that is fixed to a work stage and floats with respect to a central shaft. The cooling fluid supplied from the fluid source is circulated through the flow path in the coil housing to cool the heat generated by the coil of the linear motor and prevent thermal deformation of the work stage.

The cooling fluid is supplied from the fluid source to the coil housing via a flexible tube, and the tube is bent in accordance with the movement of the coil housing as the work stage moves, so that the cooling flow path is formed. It comes to secure.
JP 2001-218443 A

  However, as shown in Patent Document 1, when adopting a method of supplying a cooling fluid to a housing coil that moves together with a table, it is necessary to provide a flexible or movable tube, and durable use of the tube In addition to the above problems, there is a problem that the apparatus becomes large in order to secure an installation space for the moving tube. There is also a problem that the reaction force due to the bending of the tube affects the positioning of the table.

  The present invention has been made in view of the above-described circumstances, and efficiently cools the heat generated in the coil to prevent thermal deformation of the table and the like. An object of the present invention is to provide a stage device and a machine tool that can prevent an increase in size.

In order to achieve the above object, the present invention provides the following means.
The present invention comprises a base, a table, guide means for supporting the table so as to be movable in the horizontal direction with respect to the base, and a linear motor for propelling the table in the horizontal direction with respect to the base, The linear motor includes a cylindrical movable member fixed to the table, and an internal shaft fixed to the base and penetrated through a central hole of the movable member, and the internal shaft is formed on an inner surface of the central hole of the movable member. A plurality of annular permanent magnets arranged in the axial direction, and a coil that forms a magnetic field acting on the permanent magnet of the movable member on the internal shaft, and the internal shaft penetrates in the axial direction. and cooling flow passage for circulating cooling oil inside is provided, configured so that the cooling passage is discharged directly to the outside of the oil pan oil that has flowed from one end from the other end Is, the guide means provided with a static pressure pad for supporting the state of floating table relative to the base by the hydraulic pressure is arranged between the table base, parallel to the static pressure pad and the cooling channel A stage device including a pressure oil supply device for supplying oil to the tank .

  According to the present invention, by supplying a current to the coil in the internal shaft of the linear motor, a magnetic field is formed around the internal shaft, and the magnet of the movable member arranged in the magnetic field has an axial direction of the internal shaft. Is generated, and the table is propelled in the horizontal direction with respect to the base. Since the table is supported by the guide means so as to be movable in the horizontal direction with respect to the base, the table is stably and accurately guided in the horizontal direction even when a heavy object is mounted.

  In this case, in the internal shaft, the coil generates heat due to the supplied current. However, since a cooling flow path that penetrates the internal shaft in the axial direction is provided, the cooling that can be circulated in the cooling flow path. The heat generated in the coil is cooled by the working fluid. Since the internal shaft is fixed to the base, a pipe that supplies the cooling fluid to the cooling flow path of the internal shaft can be a fixed pipe. As a result, there is no need to provide a movable tube, the installation space can be minimized, and the apparatus can be miniaturized. In addition, the positioning accuracy of the table can be improved without receiving a reaction force due to the bending of the tube. Further, the cooling fluid can be discharged directly from the internal shaft to the outside without being drawn out to the table side, and thermal deformation of the table can be more reliably prevented without performing complicated heat insulation treatment.

  In addition, by using a hydrostatic pad that supports the table in a floating state with respect to the base by the pressurized oil supplied from the pressure oil supply device as the guide means, the propulsive force is applied to the table without wear of the machine parts. It is possible to provide a stage apparatus that takes full advantage of the added linear motor.
  In this case, the linear motor can be cooled by diverting oil from the pressure oil supply device required for the static pressure pad and flowing it in parallel with the cooling flow path of the internal shaft. Thereby, the oil for linear motor cooling and the oil to a static pressure pad can be supplied with a common pressure oil supply apparatus, and the structure of an apparatus can be simplified.

Further, in the above-mentioned invention, the pressure oil supply device, it is preferable that the pressure oil temperature control device for controlling the temperature of the oil is provided.
Static pressure pad for supporting the state of floating table relative to the base by hydraulic pressure, the temperature in the thus positional accuracy of the oil used is varied, controlling the temperature of the oil in a predetermined range by operation of the hydraulic fluid temperature control device by, Ru can be maintained high positional accuracy.

Moreover, in the said invention, it is good also as the oil discharged | emitted from the said static pressure pad distribute | circulated through the cooling flow path formed in the internal shaft of the said linear motor.
As described above, temperature-controlled oil is supplied to the static pressure pad. The hydrostatic pad is not a large heat source, and the oil that has been circulated through the hydrostatic pad maintains a temperature close to the controlled temperature. Therefore, by circulating the oil discharged from the static pressure pad through the cooling flow path, the heat generated by the linear motor can be cooled and the deterioration of positioning accuracy can be prevented.

The present invention also provides a machine tool including the above-described stage device and mounting a workpiece or a tool on the table.
According to this invention, the guide is propelled with high positioning accuracy by the operation of the linear motor while the table is accurately guided. Therefore, the workpiece mounted on the table can be processed with high accuracy, or the workpiece mounted on the table can be moved with high accuracy to process the workpiece with high processing accuracy.

  According to the present invention, a linear motor having a coil on the internal shaft is adopted, and the cooling fluid is circulated through the cooling flow path formed through the internal shaft fixed to the base, thereby efficiently generating heat of the coil. Even if it cools and does not employ | adopt a complicated heat insulation structure, it can discharge | emit, without transferring the heat | fever of the heated cooling fluid to the table side. Further, by allowing the cooling fluid to flow through the cooling flow path of the internal shaft fixed to the base, the entire apparatus can be made compact while eliminating the movable piping and maintaining high positioning accuracy of the table.

Hereinafter, a stage apparatus according to an embodiment of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, the stage apparatus 1 according to the present embodiment is a stage apparatus 1 of a machine tool 2, and includes a table 3 on which a base 3 and a chuck 4 that holds a workpiece (workpiece member) W are mounted. And. Reference numeral 6 in the drawing denotes a tool for processing (cutting or the like) the workpiece W.

As shown in FIG. 2, between the base 3 and the table 5, the guide means 7 that supports the table 5 so as to be horizontally movable with respect to the base 3, and the table 5 is pushed horizontally with respect to the base 3. The linear motor 8 is provided.
As shown in FIG. 2, the guide means 7 supplies the pressurized oil to the plurality of recesses 9 in which the surface facing the base 3 of the table 5 that is arranged with a minute gap with respect to the base 3 is recessed. It comprises a plurality of supplied static pressure pads (hereinafter also referred to as static pressure pads 7). The supply of pressurized oil will be described later.

  The static pressure pads 7 are respectively provided at positions facing each other with the base 3 or the table 5 sandwiched in the horizontal direction and the vertical direction. By supplying oil of a predetermined pressure to these static pressure pads 7 and applying a static pressure to the table 5 in the vertical direction and the horizontal direction to balance, the table 5 is moved in the vertical direction and the horizontal direction with respect to the base 3. It can be maintained in a state of floating in the direction.

  Further, as shown in FIG. 1, the linear motor 8 includes an internal shaft 12 fixed to the base 3 by a bracket 10 and a nut 11, and a slider (movable member) 13 fixed to the table 5. Yes. The internal shaft 12 has a built-in coil (not shown) that generates a magnetic field around it by a current supplied from the outside, and a through-hole 14 that penetrates in the axial direction. The slider 13 is formed in a substantially cylindrical shape, and the inner shaft 12 is arranged in a penetrating state in the central hole 13a. A plurality of annular permanent magnets 15 are arranged on the inner surface of the central hole 13a of the slider 13 along the axial direction. The permanent magnets 15 are arranged with the north and south poles alternately oriented in the opposite direction along the axial direction.

  Therefore, when a current is supplied to the coil of the internal shaft 12 and a magnetic field is formed around the internal shaft 12, the slider 13 is moved relative to the internal shaft 12 by the action of the magnetic force of the permanent magnet 15 disposed in the magnetic field. It can be propelled in the axial direction. The slider 13 can be positioned at an arbitrary horizontal position with respect to the internal shaft 12 by controlling the current applied to the coil.

Next, supply of oil to the stage apparatus 1 according to the present embodiment will be described.
The stage device 1 according to the present embodiment includes an oil supply device 16 that supplies pressurized oil to the static pressure pad 7. As shown in FIG. 3, the oil supply device 16 adjusts the temperature of the oil in the oil tank 17, the motor pump 18 that pressurizes and sends out the oil in the oil tank 17, and the oil in the oil tank 17. And an oil temperature adjusting device 19 is provided. In the figure, reference numeral 20 is a strainer, reference numeral 21 is an oil level gauge, reference numeral 22 is a filter, reference numeral 23 is an accumulator, reference numeral 24 is a pressure gauge, reference numeral 25 is a pressure switch, and reference numeral 26 is an oil pan.

By the operation of the oil supply device 16, oil adjusted to a predetermined pressure and temperature is supplied to each static pressure pad 7 via an oil supply pipe 27.
The oil supply device 16 is also connected to a through hole 14 provided in the internal shaft 12 via an oil supply pipe 28. Thereby, the oil adjusted to a predetermined temperature by the oil supply device 16 is allowed to flow through the through hole 14 of the internal shaft 12.
The oil discharged from the static pressure pad 7 and the linear motor 8 is collected in the oil pan 26 and returned to the oil tank of the oil supply device.

  The tool table 29 on which the tool 6 is mounted is also provided with a static pressure pad 30 and a linear motor (not shown). The static pressure pad 30 and the linear motor are also supplied with temperature via oil supply pipes 27 and 28. The oil of the adjusted predetermined pressure is supplied.

The operation of the stage apparatus 1 according to the present embodiment configured as described above will be described below.
In order to horizontally move the workpiece W by the stage device 1 according to the present embodiment, first, the oil supply device 16 is operated, and the oil adjusted to a predetermined temperature by the oil temperature adjustment device 19 is added by the motor pump 18. Supply pressure. By supplying the oil to the static pressure pad 7, the table 5 is supported in a state where it floats with respect to the base 3 in the vertical direction and the horizontal direction. Since the temperature of the oil is adjusted to a predetermined temperature, the table 5 and the base 3 are not thermally deformed by the heat generated by the oil, and the oil is maintained at the predetermined temperature. Further, when the oil supply device 16 is operated, the oil supply device 16 is also circulated through the through hole 14 of the internal shaft 12 constituting the linear motor 8.

  Next, a current is supplied to the coil of the linear motor 8 to apply a propulsive force to the table 5 in the horizontal direction. In this case, the moving speed of the table 5 and the position of the table 5 can be adjusted by controlling the current supplied to the coil.

  Since the coil of the linear motor 8 is disposed in the internal shaft 12, the coil supplied with the current generates heat according to the current value and the resistance value, and heats the internal shaft 12. According to the stage device 1 according to the present embodiment, since the temperature-controlled oil from the oil supply device 16 is circulated through the through hole 14 formed in the internal shaft 12, the heat generated in the coil is oil. Therefore, heating of the slider 13 due to heat generated by the internal shaft 12 and further heating of the table 5 connected to the slider 13 are prevented. Therefore, the occurrence of thermal deformation in the table 5 is prevented, and a decrease in positioning accuracy of the table 5 can be prevented.

  In this case, the cooling of the linear motor 8 is performed by circulating oil through the through hole 14 provided in the internal shaft 12 fixed to the base 3, so that the internal shaft 12 penetrates from the oil supply device 16. An oil supply pipe 28 that supplies oil to the hole 14 can be a fixed pipe. As a result, unlike the conventional method that requires a movable tube to cool the coil disposed on the table 5 side, it is not necessary to secure a moving space for the oil supply tube. In addition, since the reaction force due to the bending of the tube is not received, the positioning accuracy of the table can be improved.

  Also, in order to ensure the durability of the movable part, unlike the case of a movable tube that had to bend a sufficiently long tube with a sufficiently large radius of curvature, oil is supplied by using a fixed pipe. The installation space of the pipe 28 can be reduced, and there is an advantage that the durability is not lowered even when the pipe 28 is bent with a small radius of curvature.

  Furthermore, in the stage apparatus 1 according to the present embodiment, the heated oil after cooling the internal shaft 12 can be discharged directly from the other end of the through hole 14 of the internal shaft 12 to the external oil pan 26. Compared to the conventional method of discharging and collecting the table 5 once it has been pulled out above the table 5, it is possible to more reliably prevent the table 5 from being heated by the heated oil by cooling the internal shaft 12. be able to.

  Therefore, according to the stage apparatus 1 according to the present embodiment, the static pressure pad 7 that supports the table 5 in a state of floating with respect to the base 3, and the state in which the slider 13 is floated with respect to the internal shaft 12. In combination with the linear motor 8 for applying a propulsive force, it is possible to provide an ideal stage device 1 with no wear or backlash of machine parts. Moreover, since the heat of the coil in the internal shaft 12 is cooled by the temperature-controlled oil, the temperature rise of the table 5 can be prevented to suppress thermal deformation, and the deterioration of positioning accuracy can be prevented. And the oil supply piping 28 can be comprised only by fixed piping, and the compactness of stage apparatus 1 and the improvement of durability can be aimed at.

  Further, according to the stage apparatus 1 according to the present embodiment, the heat of the linear motor 8 is cooled using the temperature-adjusted oil supplied to the static pressure pad 7, so that the oil temperature is adjusted for cooling the linear motor 8. There is no need to separately provide a device or an oil supply device, and the configuration can be simplified and the product cost can be reduced.

  In addition, the machine tool 2 including the stage device 1 according to the present embodiment can move the chuck 4 for moving the workpiece W mounted on the table 5 with high accuracy, and performs precise machining with reduced errors. It can be carried out. If the static pressure pad 30 and the linear motor are provided on the tool base 29, there is an advantage that the positional accuracy on the tool 6 side can be further increased and more precise machining can be performed.

  In the present embodiment, as shown in FIG. 3, oil is supplied in parallel to the static pressure pad 7 and the through hole 14 of the internal shaft 12 from a single oil supply device 16. Instead, the oil supplied to and discharged from the static pressure pad 7 may be circulated through the through hole 14 of the internal shaft 12. In this case, since the pressure of the oil is reduced when it is discharged from the static pressure pad 7, it is necessary to pressurize again by a pump (not shown).

It is the front view which fractured | ruptured one part which shows the machine tool provided with the stage apparatus which concerns on one Embodiment of this invention. It is the side view which fractured | ruptured a part explaining the static pressure pad of the stage apparatus of FIG. It is a circuit diagram explaining the supply system of the oil in the stage apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage apparatus 2 Machine tool 3 Base 5 Table 7 Static pressure pad (guide means)
8 Linear motor 12 Internal shaft 13 Movable member 13a Central hole 14 Through hole (cooling flow path)
15 Permanent magnet 16 Oil supply device (pressure oil supply device)
19 Oil temperature control device (pressure oil temperature control device)
W Workpiece (Workpiece member)

Claims (4)

Base and
Table,
Guide means for supporting the table movably in the horizontal direction with respect to the base;
A linear motor for propelling the table horizontally with respect to the base;
The linear motor includes a cylindrical movable member fixed to the table, and an internal shaft fixed to the base and penetrated through a central hole of the movable member,
The inner surface of the central hole of the movable member includes an annular permanent magnet that surrounds the inner shaft and is arranged in the axial direction.
The internal shaft is provided with a coil that forms a magnetic field that acts on the permanent magnet of the movable member, and a cooling passage that passes through the internal shaft in the axial direction and circulates a cooling fluid therein.
The cooling flow path is configured to discharge the cooling fluid flowing from one end directly to the external oil pan from the other end,
The guide means includes a static pressure pad that is disposed between the table and the base and supports the table in a floating state with respect to the base by hydraulic pressure, and oil is provided in parallel to the static pressure pad and the cooling flow path. A stage device including a pressure oil supply device for supplying oil. The stage device according to claim 1, wherein the pressure oil supply device is provided with a pressure oil temperature control device that controls the temperature of the oil. The stage apparatus according to claim 1 or 2 , wherein oil discharged from the static pressure pad is circulated through a cooling flow path formed in an internal shaft of the linear motor. A stage apparatus according to any one of claims 1 to 3 , comprising:
A machine tool for mounting a workpiece or a tool on the table.

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