Rotary table device

Abstract

To accurately detect a position of a table which is rotated with respect to a bed, over a whole circumference and to facilitate assembly by insulating the bed and the table by coating an armature assembly with an insulation layer in a rotary table device.SOLUTION: A ring member 17 comprising a ring scale 20 extending over a whole circumference is disposed in a shaft part 10 of a table 2 in which a field magnet 4 is disposed in a whole circumference. A sensor 21 which reads the ring scale 20 is disposed in a bed 1 in which an armature coil 6 is disposed in a circumferential direction oppositely to the field magnet 4.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a rotary table device incorporating a linear motor composed of, for example, an armature assembly disposed on the bed side and a field magnet disposed on the table side, and is used in mechanical devices such as semiconductor manufacturing apparatuses, measuring instruments, machine tools, and industrial robots.

Background Art

[0002] In recent years, in various technical fields using mechanical devices, in X-Y and other multi-axis stages and moving mechanism parts, in order to move a moving body such as a workpiece or a device at high speed and position the table of the moving body with high precision with respect to a base such as a bed, a high-thrust, high-speed, and high-response slide device having a compact and lightweight structure for the bed and the table has been demanded. As a driving device for moving the table of the slide device, a linear motor is used. Generally, as a linear motor, there are a movable coil type linear motor provided with a plurality of armature coils as a mover and a movable magnet type linear motor provided with a field magnet as a mover.

[0003] Conventionally, as an alignment stage device, there is known one in which a disk-shaped table is configured to be rotatable with respect to a fixed bed at a predetermined rotation angle. The alignment stage device rotationally drives a table rotatably supported on the bed via bearings by a linear motor. The linear motor is composed of an armature coil consisting of a three-phase coreless coil with a flat and annularly wound primary side, and a field magnet with a secondary side composed of a large number of plate-shaped magnets. In the above alignment stage device, the armature coils are respectively disposed on the bed side, and the magnets are respectively disposed in the circumferential direction on the table side, with the armature coils and the magnets facing each other. Further, the armature assembly is composed of an annular substrate formed along a plurality of magnets disposed in the circumferential direction of the table, and armature coils respectively fixed to the substrate. The armature assembly is fixed to the bed. Further, a tape-shaped scale is adhered to the outer peripheral surface of the table in a range corresponding to the rotation angle of the table, and the position of the table is detected by reading the scale with an optical sensor disposed on the bed. Also, an insulating sheet is disposed between the armature assembly and the bed and the table. The armature assembly is insulated from the bed and the table by the insulating sheet (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the above alignment stage device oscillates within a predetermined rotation angle, it does not have the technical concept of providing a scale around the entire circumference of the table and rotating infinitely. That is, the above alignment stage device adheres a tape-shaped scale to the range corresponding to the rotation angle. Therefore, if the table is to be rotated infinitely, the tape-shaped scale for position detection will be adhered over 360° of the entire circumference of the table. In this case, it is difficult to align the joints of the scale, and it is difficult to stabilize the quality. In addition, the above alignment stage device separately disposes an insulating sheet for insulating between the armature assembly, the bed, and the table. Therefore, there is a problem that the number of parts increases and the assembly man-hours increase because the insulating sheet is sandwiched during table assembly. In addition, it becomes difficult to align the positions of the attachment holes and the like of the armature assembly and the insulating sheet when disposing them on the bed. Also, in the conventional alignment stage device, a separate insulating sheet was sandwiched between the bed and the armature coil during table assembly.

[0006] An object of the present invention is to solve the above problems, and a rotary table device that infinitely rotates a table with respect to a bed installed at a predetermined position, provided with a ring scale over the entire circumference on a ring member disposed around the entire circumference of the shaft portion of the table, and also covering the armature assembly with an insulator to insulate between the bed and the table, easily configured for assembly, capable of measuring the position of the table over the entire circumference with respect to the bed and detecting the position of the rotating table with high precision, and increasing the degree of freedom in the design of the table provided with the field magnet and the bed provided with the armature assembly while providing a rotary table device characterized by being compactly configured.

Means for Solving the Problems

[0007] This invention relates to a rotary table device having a bed installed at a predetermined location, a disk-shaped table rotatably attached to the bed via a bearing, and a motor for rotationally driving the table. A plurality of armature coils constituting an armature assembly on the primary side of the motor are composed of flat, annularly wound three-phase coreless coils and are respectively arranged along the circumferential direction in an annular recess on the bed. A plurality of magnets constituting a field magnet on the secondary side of the motor are formed in a plate shape and are respectively arranged along the circumferential direction with alternating magnetic poles facing the armature coils in an annular recess on the lower surface of the table. The table is composed of a shaft portion located on the lower surface where the field magnet is arranged and facing the bed, and a mounting portion that is integrally structured with the shaft portion for attaching a mating member. A ring member extending over the entire circumference is arranged on the shaft portion of the table, a ring scale is provided over the entire outer peripheral surface of the ring member, and a sensor for reading the ring scale is arranged on the bed.

[0008] Also, the outer peripheral surface of the shaft portion of the table is located inside the outer peripheral surface of the mounting portion, and the outer peripheral surface of the ring scale attached to the shaft portion of the table is located inside the outer peripheral surface of the mounting portion.

[0009] Also, the ring member is fixed to the outer peripheral surface of the shaft portion of the table by inlay fitting.

[0010] Also, the inner peripheral surface of the ring member fitted into the shaft portion of the table is formed as a tapered surface along the insertion direction of the outer peripheral surface of the shaft portion of the table.

[0011] Also, the armature assembly is composed of a ring-shaped substrate formed along the arrangement direction of a large number of the magnets, and the armature coils sequentially arranged on the substrate along the arrangement direction of the magnets. Further, the armature assembly is provided with a first insulating layer provided on the armature coil side and a second insulating layer formed on the substrate side.

[0012] Also, the first insulating layer is an insulating plate adhered to the armature assembly, and the second insulating layer is an insulating sheet adhered to the substrate or an insulating film applied to the substrate.

Advantages of the Invention

[0013] As described above, the rotary table device according to this invention incorporates a movable magnet type linear motor, forms a ring scale on a seamless ring member extending over the entire circumference of the shaft portion of the table, and can easily and properly attach the ring member provided with the scale to the shaft portion of the table. Further, in this rotary table device, the scale surface located on the outer peripheral surface of the ring member is arranged inside the outer peripheral surface of the table, preventing the problem of accidentally touching the scale, and since the ring member is inro-fitted to the outer peripheral portion of the table, the ring member can be accurately fixed to the table. Furthermore, since a tapered surface along the table insertion direction is formed on the inner peripheral surface of the ring member, the ring member can be easily inserted and attached to the shaft portion of the table. Also, in some cases, the ring scale can be directly formed on the ring member, enabling a simple configuration. Also, in this rotary table device, since insulating layers are pre-formed on both sides of the armature assembly in which the armature coils are arranged on the substrate, insulation can be achieved between the bed and the table just by incorporating the armature assembly, eliminating the need to separately prepare an insulating sheet. Since the armature assembly is configured in an integrated one-piece structure of the substrate, armature coils, and insulating layers, the armature assembly can be easily incorporated into the bed and assembled easily and properly.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0015] Hereinafter, with reference to the drawings, an embodiment of a rotary table device according to the present invention will be described. The rotary table device according to the present invention is used in mechanical devices such as semiconductor-related devices, measuring instruments, machine tools, industrial robots, and conveyors. For example, it incorporates a linear motor configured by disposing an armature assembly 3 on the bed 1 side and a field magnet 4 on the table 2 side. This rotary table device is, for example, mounted on an XY table device which is an orthogonal positioning device and is used to achieve alignment of angular positions. On the bed 1, through holes 13 are provided at the center, and mounting holes 33 for attachment to a base, pedestal, etc. are provided at the four corners, and it is configured such that a table 2 drivable in the X-axis direction and the Y-axis direction can be fixed to the base 1. Also, on the table 2, mounting holes 23 for attaching mating members such as other parts and workpieces are provided. The table 2 is formed in a disk shape, for example, by nickel-plated steel magnetic material iron. A through hole 12, which is a through hole, is formed at the center of the table 2. Wiring and piping can be passed through the through hole 12 to the upper surface 47 of the table 2, and the table 2 is configured to be lightened by the amount of the through hole 12.

[0016] Generally, as shown in FIGS. 1 to 6, the rotary table device according to the present invention has a bed 1 on the fixed side installed at a predetermined location, a table 2 such as a disk-shaped turntable rotatably attached to the bed 1 via a bearing 5 such as a cross roller bearing, and a linear motor which is a permanent magnet type motor for driving the table 2 to rotate relatively. The cross roller bearing is a bearing 5 in which rollers are arranged with the axial center lines of adjacent rollers orthogonal to each other, and is composed of an outer ring 14 fixed to the bed 1 by fixing screws 26, an inner ring 15 fixed to the table 2 by fixing screws 25, and a plurality of rollers 16 alternately arranged and crossing between the outer ring 14 and the inner ring 15. Since it is compact and can simultaneously receive radial load, axial load, and moment, the size of the device can be made small, and it can be configured as a flat device with a low cross-sectional height.

[0017] The linear motor is composed of an armature assembly 3 consisting of a plurality of armature coils 6 on the primary side and a field magnet 4 consisting of a plurality of magnets 9 on the secondary side. The armature coils 6 are each formed of a three-phase coreless coil wound flatly and annularly, wound in a trapezoidal shape, and arranged along the circumferential direction on the circular plane of the annular recess 19 formed on the upper surface of the bed 1. The armature coils 6 are arranged on the bed 1 without a gap with the upper base, which is the short side, facing the rotation center of the table 2. As a result, the arm portion connecting the upper base and the lower base of the armature coil 6 becomes longer and the area increases, so that the thrust of the table 2 can be increased. Each armature coil 6 is molded with an insulating resin (not shown) and fixed to a substrate 7 which is a ring-shaped printed circuit board, that is, a coil substrate. Further, the magnet 4 is plate-shaped and formed in a trapezoidal shape, and is arranged along the circumferential direction with magnetic poles alternately different on the circular plane of the annular recess 18 formed on the lower surface 32 of the table 2, and is arranged to face the armature coil 6. The table 2 also serves as a magnet yoke that forms the magnetic path of the field magnet 4. The permanent magnet motor that rotationally drives the table 2 is a four-pole three-phase motor, a linear motor having the armature coil 6 that constitutes the primary side armature assembly 3 and the magnet 9 that constitutes the secondary side field magnet 4, and is a direct drive type motor that directly rotationally drives the table 2.

[0018] The rotary table device according to the present invention is characterized in that it is disposed over the entire outer peripheral surface of the shaft portion 10 of the table 2 via a ring member 17 having a seamless ring scale 20 extending over the entire circumference. The table 2 includes an upper mounting portion 11 for mounting a mating member such as a workpiece or a device, and a shaft portion 10 having a smaller diameter than the mounting portion 11 and located below, which is integrally formed and in which the armature coil 6 is disposed on the side facing the bed 1. In other words, a ring member 17 extending over the entire circumference of the outer peripheral surface 41 of the shaft portion 10 of the table 2 is disposed, and a ring scale 20 is provided over the entire area of the outer peripheral surface 42 of the ring member 17. A sensor 21 (reading head) for reading the ring scale 20 is disposed on the bed 1. As shown in FIGS. 8 and 9, an optical sensor 21 for reading the scale surface, which is the outer peripheral surface 44 of the ring scale 20, is fixed via a support base 39 fixed to the bed 1 and is covered with a cover 22 fixed to the bed 1. A gap 35 through which the sensor 21 can read the scale surface is formed between the scale surface and the sensor 21. Note that FIG. 8 is a view in which the table 2 and the magnet 9 are omitted.

[0019] Also, in this rotary table device, the outer peripheral surface 41 of the shaft portion 10 of the table 2 is located inside the outer peripheral surface 43 of the mounting portion 11, and the outer peripheral surface 44 of the ring scale 20 attached to the shaft portion 10 is located inside the outer peripheral surface 43 of the mounting portion 11. Further, the ring member 17 is fixed to the outer peripheral surface 42 of the shaft portion 10 of the table 2 by an inlay fit. Also, the inner peripheral surface 45 of the ring member 17 fitted into the shaft portion 10 of the table 2 is formed as a tapered surface 30 along the insertion direction of the outer peripheral surface 41 of the shaft portion 10 of the table 2. Furthermore, the armature assembly 3 is composed of a substrate 7 which is a ring-shaped coil substrate formed along the arrangement direction of a large number of magnets 9, and armature coils 6 sequentially arranged on the substrate 7 along the arrangement direction of the magnets 9. The armature assembly 3 includes a first insulating layer 36 provided on the armature coil 6 side and a second insulating layer 37 provided on the substrate 7 side, and is integrated. Also, the first insulating layer 36 is an insulating plate adhered to the armature assembly 3, and the second insulating layer 37 is composed of an insulating sheet adhered to the substrate 7 or an insulating film applied to the substrate 7.

[0020] This rotary table device is specifically formed as follows. That is, the substrate 7 constituting the armature assembly 3 is, for example, a four-layer printed circuit board formed of glass epoxy resin with a plurality of circuit patterns formed in layers. The circuit patterns are connected through through-holes (not shown) and are connected to the armature coil 6. On the surface of the substrate 7 where the armature coil 6 is fixed, an insulating film is formed, for example, a two-layer insulating film by double resist processing. On the opposite surface of the substrate 7, an insulating film is formed, for example, a one-layer insulating film by single resist processing. Here, for the resist processing, well-known resist processing such as solder resist processing, which pattern-prints and cures an ultraviolet-curable or thermosetting resin on the substrate 7 by screen printing, can be used. Note that the armature assembly 3 can be made with single resist processing instead of double resist processing. In short, insulating films are formed on both sides of the substrate 7 so as to improve the electrical leakage from the substrate 7 and the noise resistance of the substrate 7. By fixing the armature coil 6 configured in this way to the entire circumference of the substrate 7, the armature assembly 3 shown in FIG. 5 is configured. Here, the armature assembly 3 is composed of three armature coils 6 to which currents of each phase are supplied in a three-phase (U, V, W phase) energization method and a set in which four magnets 9 correspond to each of them. And power lines (not shown) can be connected to the tongue-shaped lands 31 on the outer peripheral side of the substrate 7 to supply power to the armature coil 6. The lands 31 are provided with connection parts corresponding to, for example, the U, V, and W phases, and power lines can be connected to these connection parts by soldering or the like. The armature assembly 3 configured in this way can dispose the armature coil 6 on the bed 1 by turning the armature coil 6 downward (toward the bed 1 side) and screwing it to the bed 1 through a resin-made collar 34. The space between the armature coil 6 and the magnet 9 is blocked by the substrate 7, and the heat generated by the armature coil 6 is difficult to be transmitted to the magnet 9. That is, the thrust of the permanent magnet type motor is proportional to the magnetic flux density of the magnet 9. Here, the magnetic flux density depends on temperature. When the temperature of the magnet 9 rises, the magnetic flux density may decrease and the thrust of the motor may decrease.However, according to this embodiment, since the substrate 7 shields between the armature coil 6 and the magnet 9, the heat of the armature coil 6 is difficult to transfer to the magnet 9, and a decrease in thrust due to temperature rise can be suppressed. Further, in this rotary table device, since the magnet 9 is air-cooled by the air flow accompanying the rotation of the table 2, a decrease in thrust due to temperature rise can be further suppressed. As a result, in this embodiment, a cooling device for cooling the magnet 9 or the like can be made unnecessary, and the device can be made compact. Further, since an annular concave portion 19 is formed in the bed 1 and the armature coil 6 is disposed so as to be accommodated in the concave portion 19, the cross-sectional height of the device can be made low.

[0021] Specifically, as shown in FIG. 5, a magnet 9 is disposed on the lower side (back side) of the table 2. In this embodiment, each magnet 9 is circumferentially disposed along a predetermined curvature. Since each magnet 9 is disposed so as to be accommodated in an annular recess 18 formed circumferentially on the lower side (back side) of the table 2, the sectional height of the table 2 with the magnet 9 attached can be made low, and a compact configuration can be achieved. The magnet 9 is, for example, a rare earth neodymium-based permanent magnet and is formed in a trapezoidal plate shape corresponding to the armature coil 6. Further, the magnet 9 can be, for example, fitted into the annular recess 18 of the table 2 and fixed with an adhesive. In addition, when the magnet 9 can be firmly fixed to the table 2 made of a magnetic material by magnetic force, it can be fixed only by magnetic force without using an adhesive. Further, the magnet 9 is disposed on the entire circumference of the table 2 so as to face the armature coil 6. The magnets 9 are disposed in close contact with each other in the circumferential direction, and the magnetic poles are alternately disposed, that is, the adjacent magnets 9 are disposed so as to be N poles and S poles with respect to each other. In this embodiment, this rotary table device can be configured such that, for example, three armature coils 6 and four magnets 9 form a set, and six sets of these are provided. In other words, the relationship is such that there are 3×n armature coils 6 and 4×n magnets 9. Specifically, 18 armature coils 6 are disposed on the bed 1 in a number of 3×6, and 24 magnets 9 are disposed on the table 2 in a number of 4×6. And the armature coil 6 is configured corresponding to 3 coils, and the magnet 9 is configured corresponding to 4 poles.

[0022] Regarding this rotary table device, the ring scale 20 disposed on the outer peripheral surface 41 of the shaft portion 10 of the table 2 will be described. A ring member 17 provided with the ring scale 20 is fixed to the outer peripheral surface 41 of the shaft portion 10 of the table 2. The ring scale 20 is an optical scale, and as shown in FIG. 7, a scale is formed over the entire circumference on the outer peripheral surface 42 of the ring member 17. In this embodiment, specifically, as shown in FIG. 4, the inner peripheral surface 45 of the ring member 17 is inserted into the shaft portion 10 of the table 2 and inrolled and fitted, and the fixing screw 24 is screwed into the mounting screw hole 29 formed in the mounting portion 11 of the table 2 to be fixed to the table 2. A tapered surface 30 along the insertion direction of the table 2 is formed on the inner peripheral surface of the ring member 17, and the ring member 17 is configured to be easily inserted into the shaft portion 10 of the table 2. At this time, the ring member 17 is disposed in a kind of undercut accommodation space 27 formed by the lower surface of the mounting portion 11 of the table 2 and the outer peripheral surface 41 of the shaft portion 10 so that the scale surface, which is the outer peripheral surface 44 of the ring scale 20, is inside the outer peripheral surface 43 of the mounting portion 11 of the table 2. In other words, an axial portion 10 recessed inward from the outer peripheral surface 43 of the mounting portion 11 of the table 2 is formed on the outer peripheral surface 41 of the shaft portion 10 of the table 2 into which the ring member 17 can be inserted, the ring member 17 is inserted into the axial portion 10, and the ring member 17 is fixed with the fixing screw 24 so that the ring member 17 can be fixed to the table 2. An optical encoder capable of detecting the position of the table 2 with respect to the bed 1 is configured by these ring scale 20 and sensor 21. Note that power lines and signal lines (not shown) are configured to be connected to the sensor portion. Thus, in this rotary table device, since the seamless ring scale 20 is used, a scale can be easily provided over the entire circumference of the table 2. Further, since the ring scale 20 is formed on the outer peripheral surface 42 of the ring member 17 having a long circumference of the table 2, the ring scale 20 can be finely engraved, enabling highly accurate position detection.Furthermore, since the ring member 17 is press-fitted into the outer peripheral portion which is the shaft portion 10 of the table 2, the ring member 17, and thus the ring scale 20, can be accurately attached to the table 2, and the center of rotation of the table 2 and the center of the ring scale 20 can be easily aligned. Also, in this embodiment, since the scale surface of the ring scale 20 is disposed inside the outer peripheral surface 43 of the placement portion 11 of the table 2, it is possible to prevent accidental contact with the scale surface. As a result, it is possible to avoid the problem that the scale surface becomes dirty and the sensor 21 cannot read it. In this embodiment, a spacer 28 is disposed between the table 2 and the ring scale 20 to adjust the position of the ring scale 20, but it is also possible to eliminate the spacer 28 by adjusting the dimensions of the table 2 and the ring scale 20 themselves.

[0023] Next, the insulation structure of the armature assembly 3 in this rotary table device will be described. As shown in FIG. 10, an insulating plate 36 serving as a first insulating layer is provided on the surface of the armature assembly 3 on the side of the armature coil 6. The insulating plate 36 is, for example, a plate formed of a glass epoxy resin which is an insulating material and has a thickness of 0.2 mm. The insulating plate 36 is fixed to the armature assembly 3 by, for example, an adhesive. Further, as shown in FIG. 11, an insulating sheet 37 serving as a second insulating layer is provided on the surface of the armature assembly 3 on the side of the substrate 7. The insulating sheet 37 is, for example, a sheet formed of a glass epoxy resin which is an insulating material and has a thickness of 0.2 mm in a thin plate shape. The insulating sheet 37 is fixed to the armature assembly 3 by, for example, an adhesive. The insulating plate 36 and the insulating sheet 37 are configured to prevent the current leaked from the armature assembly 3 from being transmitted to the outside, and also to prevent noise from the outside from entering the internal circuit or the like. Thus, since the insulating plate 36 and the insulating sheet 37 are adhered to the armature assembly 3 in advance, the armature assembly 3 can be insulated only by being incorporated into the bed 1. That is, in the conventional rotary table device, a separate insulating sheet was sandwiched between the armature assembly, the bed, and the table during assembly, so the assembly was complicated. However, according to the embodiment of the rotary table device according to the present invention, this operation can be omitted, the assembly can be easily performed, and the manufacturing cost can be reduced. Further, since the insulating plate 36 and the insulating sheet 37 are directly fixed to the armature assembly 3, the insulation performance can be improved and a sufficient insulation withstand voltage can be ensured. Further, since the insulating plate 36 and the insulating sheet 37 are fixed so as to cover the armature coil 6, the armature coil 6 can be protected by the insulating layer. Further, in this embodiment, since the armature coil 6 and the magnet 9 are arranged horizontally, a thin rotary table device can be realized. Further, since the table 2 can be configured to be thin, the mass on the outer peripheral side of the table 2 having a large rotation radius can be configured to be small, and the moment of inertia can be reduced. Further, since a through hole 12 is provided in the central portion of the table 2 to lighten the entire table, the moment of inertia can be further reduced.Incidentally, in this embodiment, the armature coil 6 is disposed around the entire circumference of the printed circuit board, i.e., the board 7. However, as shown in FIG. 12, for example, the armature assembly 3' can be configured by reducing the number of one set (three) of the armature coils 6. According to this, since the land 31 can be formed at the position where the armature coil 6 is reduced, the size of the board 7 in the radial direction can be reduced. On the other hand, when the armature coil 6 is arranged around the entire circumference of the board 7 as in this embodiment, the torque of the device can be increased. Further, the insulating sheet 37, which is the second insulating layer on the board 7 side, is not limited to its adhesion. For example, a well-known insulating material can be applied to the board 7 by silk printing to form an insulating film. According to this, since the insulating film can be formed on the board 7 using the silk printing device for describing the part number etc. on the board 7 which is a printed circuit board, it is not necessary to separately prepare a device for forming the insulating film. Furthermore, if sufficient insulation resistance can be ensured with the insulating film by resist processing, the insulating sheet 37 can be eliminated. Also, in this embodiment, the armature coil 6 and the magnet 9 are formed in a trapezoidal shape, but they can also be formed in other shapes such as a rectangle, and furthermore, the armature coil 6 and the magnet 9 can be formed in different shapes. Incidentally, the rotary table device of this embodiment can be configured, for example, with an outer diameter of 200 mm of the table 2 and a height of 30 mm of the entire device, and can be made into a flat device with a low cross-sectional height. Also, the resolution of this device using the ring scale 20 is, for example, 0.21 seconds, and the repeat positioning accuracy is, for example, ±0.5 seconds, enabling high-precision positioning. Furthermore, by making the screw fixing positions of the ring scale 20 at equal intervals, the deformation of the outer peripheral surface 44, i.e., the scale surface, during screw fastening can be reduced.

Industrial Applicability

[0024] This rotary table device can be used, for example, in semiconductor manufacturing devices, various assembly devices, measuring devices, test devices, positioning tables, etc., and is particularly suitable for measuring devices and test devices etc. that require high-precision positioning.

Explanation of Reference Numerals

[0025] 1 Bed 2 Table 3,3’ Armature assembly 4 Field magnet 5 Bearing 6 Armature coil 7 Substrate 9 Magnet 10 Shaft portion 11 Mounting portion 17 Ring member 18,19 Annular recess 20 Ring scale 21 Sensor 30 Tapered surface 32 Bottom surface 36 Insulating plate (first insulating layer) 37 Insulating sheet (second insulating layer) 41,42,43,44 Outer peripheral surface 45 Inner peripheral surface

Claims

1. A rotary table device comprising a bed installed at a predetermined location, a disc-shaped table rotatably attached to the bed via a bearing, and a motor for rotationally driving the table, wherein a plurality of armature coils constituting an armature assembly on the primary side of the motor are respectively arranged along the circumferential direction in a first annular recess on the bed, and a plurality of magnets constituting a field magnet on the secondary side of the motor are formed in a plate shape and are respectively arranged facing the armature coils along the circumferential direction with alternating different magnetic poles in an annular recess on the lower surface of the table. In the rotary table device, the table is composed of a shaft portion located on the lower surface where the field magnet is arranged and facing the bed, and a mounting portion integrally structured with the shaft portion for attaching a mating member, a ring member extending over the entire circumference is arranged on the shaft portion of the table, a ring scale is provided over the entire outer peripheral surface of the ring member, and a sensor for reading the ring scale is arranged on the bed, the outer peripheral surface of the shaft portion of the table is located inside the outer peripheral surface of the mounting portion, the outer peripheral surface of the ring scale provided on the outer peripheral surface of the ring member is located inside the outer peripheral surface of the mounting portion, the sensor is arranged such that a part of it is located in a housing space formed by the lower surface of the mounting portion and the outer peripheral surface of the shaft portion, a gap formed between the outer peripheral surface of the ring scale and the sensor such that the sensor can read the ring scale is located in the housing space, the ring member is fitted into the shaft portion of the table such that a part of the inner peripheral surface of the ring member contacts a part of the outer peripheral surface of the shaft portion, the inner peripheral surface of the ring member fitted into the shaft portion of the table is formed as a tapered surface along the insertion direction of the outer peripheral surface of the shaft portion of the table, and a gap is provided between the tapered surface and the shaft portion in the radial direction. The rotary table device is characterized by this.

2. the bed is fixed to the outer ring of the bearing, and the table is fixed to the inner ring of the bearing. On the bed, a second annular recess having a surface along the outer peripheral surface of the outer ring is formed on the inner peripheral side of the first annular recess in which the armature coil is disposed, and a part of the outer ring is disposed so as to be accommodated in the second annular recess. The rotary table device according to claim 1, characterized in that.

3. The armature assembly is composed of a ring-shaped substrate formed along the arrangement direction of a large number of the magnets, and the armature coils sequentially disposed on the substrate along the arrangement direction of the magnets. The armature assembly includes a first insulating layer that is an insulating plate provided on the armature coil side and adhered to the armature assembly, and a second insulating layer that is an insulating sheet formed on the substrate side and adhered to the substrate or an insulating film applied to the substrate. The substrate, the armature coil, the first insulating layer, and the second insulating layer are integrated and are accommodated in the annular recess on the bed. The rotary table device according to claim 1 or claim 2, characterized in that.

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