Rotary table device

Abstract

A rotary table device has a base portion, a bearing provided to the base portion, a table supported by the bearing in a manner rotatable with respect to the base portion, and a motor that rotates the table with respect to the base portion in a rotation direction of the bearing. In the table, a table groove portion recessed in a radial direction of the bearing is formed in an annular shape on an outer peripheral surface over an entire circumference. The base portion includes an annular coil base disposed so as to enter the table groove portion and follow the table groove portion. The motor includes a first motor including a first magnet row of a plurality of magnets arranged on a wall surface of the table defining the table groove portion in the rotation direction of the bearing, and a first coil row of a plurality of coils arranged on a first surface of the coil base so as to face the first magnet row. The motor also includes a second motor including a second magnet row of a plurality of magnets arranged on a wall surface of the table defining the table groove portion in the rotation direction of the bearing, and a second coil row of a plurality of coils arranged on a second surface of the coil base on an opposite side from the first surface in an axial direction of the bearing so as to face the second magnet row.

Description

TECHNICAL FIELD

[0001] The present application relates to a rotary table device. This application claims priority based on Japanese Patent Application No. 2020-195910 filed on November 26, 2020, and the entire contents described in the Japanese Patent Application are incorporated into this application. BACKGROUND

[0002] A rotary table device is known that has a bed portion as a fixed portion, a rotary table as a rotating portion, and a bearing disposed therebetween. The rotary table device is known to have a direct drive servo motor in which a coil and a magnet are disposed in parallel with each other in a rotation direction, and is driven by the direct drive servo motor (for example, refer to Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2005-333763 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The above-described rotary table device is sometimes desired to be able to exert greater torque. In addition, it is also desired to be compact. Therefore, one of the objects of the present application is to provide a rotary table device that is able to exert greater torque and is compact.

[0008] MEANS OF SOLVING THE PROBLEMS

[0009] The rotary table device of the present disclosure has a base portion, a bearing provided to the base portion, a table supported via the bearing and rotatable relative to the base portion, and a motor that rotates the table relative to the base portion in the rotation direction of the bearing. On the table, a table groove portion recessed in the radial direction of the bearing is formed annularly on the outer peripheral surface over the entire circumference. The base portion includes an annular coil base that enters the table groove portion and is disposed in the manner of following the table groove portion. The motor includes a first motor and a second motor. The first motor includes a first magnet row that is a row of a plurality of magnets disposed on the wall surface of the table that defines the table groove portion in the rotation direction of the bearing, and a first coil row that is a row of a plurality of coils disposed on a first surface of the coil base in the manner of facing the first magnet row. The second motor includes a second magnet row that is a row of a plurality of magnets disposed on the wall surface of the table that defines the table groove portion in the rotation direction of the bearing, and a second coil row that is a row of a plurality of coils disposed on a second surface of the coil base on the side opposite to the first surface in the axial direction of the bearing in the manner of facing the second magnet row.

[0010] Inventive Effects

[0011] According to the above-described rotary table device, a compact rotary table device capable of exerting a large torque is provided. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 FIG. 1 is a perspective view showing a rotary table device in Embodiment 1.

[0013] Figure 2 FIG. 2 is a cross-sectional view showing the rotary table device in Embodiment 1.

[0014] Figure 3 FIG. 3 is a perspective view showing a table of the rotary table device in Embodiment 1.

[0015] Figure 4 FIG. 4 is a side view showing the table of the rotary table device in Embodiment 1.

[0016] Figure 5A FIG. 5 is a cross-sectional view showing the table in Embodiment 1.

[0017] Figure 5B FIG. 6 is a cross-sectional view showing the table and the bearing in Embodiment 1.

[0018] Figure 6 FIG. 7 is a perspective view showing a second member of the table in Embodiment 1.

[0019] Figure 7 is a plan view showing the second member of the work table and the second magnet row in Embodiment 1.

[0020] Figure 8 is a perspective view showing the first member of the work table in Embodiment 1.

[0021] Figure 9 is a perspective view showing the first member of the work table and the first magnet row in Embodiment 1.

[0022] Figure 10 is a perspective view showing the coil base in Embodiment 1.

[0023] Figure 11 is a sectional perspective view showing the coil base in Embodiment 1.

[0024] Figure 12 is a perspective view showing the coil base and the substrate in Embodiment 1.

[0025] Figure 13 is a perspective view showing the substrate and the coil in Embodiment 1.

[0026] Figure 14 is a perspective view showing the substrate and the coil in Embodiment 1.

[0027] Figure 15 is a plan view showing the rotary work table device in Embodiment 1.

[0028] Figure 16 is a schematic view showing the electrical connection of the rotary work table device in Embodiment 1. DETAILED DESCRIPTION

[0029] [Summary of Embodiments]

[0030] First, the embodiments of the present disclosure are described sequentially. The rotary table device of the present disclosure has a base portion, a bearing provided to the base portion, a table supported by the bearing so as to be rotatable relative to the base portion, and a motor that rotates the table relative to the base portion in the rotation direction of the bearing. In the table, a table groove portion recessed in the radial direction of the bearing is formed in an annular shape on the outer peripheral surface over the entire circumference. The base portion includes an annular coil base that is disposed so as to enter the table groove portion and follow the table groove portion. The motor includes a first motor and a second motor. The first motor includes a first magnet row that is a row of a plurality of magnets disposed on a wall surface of the table that defines the table groove portion in the rotation direction of the bearing, and a first coil row that is a row of a plurality of coils disposed on a first surface of the coil base so as to face the first magnet row. The second motor includes a second magnet row that is a row of a plurality of magnets disposed on a wall surface of the table that defines the table groove portion in the rotation direction of the bearing, and a second coil row that is a row of a plurality of coils disposed on a second surface of the coil base on the side opposite to the first surface so as to face the second magnet row in the axial direction of the bearing.

[0031] Conventionally, there is known a rotary table device that positions a workpiece at a prescribed position by driving a servo motor directly. Such a rotary table device is used more often for the purpose of mounting a workpiece or the like on a table and rotating the workpiece. The rotation angle is set to 60°, for example. In addition, there is a rotary table device configured to rotate 360°. In the purpose of rotating a workpiece, it is preferable that the driving force of the rotary table device be large so that the rotation operation can be reliably performed even when the mounted workpiece is large and heavy. On the other hand, if the replacement from a conventional device or the adaptability with other components is considered, the rotary table device is preferably compact and can be accommodated in a significantly different size from the conventional device.

[0032] In a case where it is desired to increase the driving force of the motor, the specifications of the coils and the magnets that constitute the motor are considered to be changed. However, there are cases where it is desired to increase the driving force without changing the coils and the magnets. In response to this demand, it is conceived to overlap the motors in two stages in the direction of the rotation shaft of the rotary table device. According to this structure, it is found that the driving force of the linear motor can be increased without changing the coils and the magnets and without changing the dimensions of the radial direction and the circumferential direction of the rotary table device. As a result of further research, it is found that the configuration of the motors overlapped in two stages is configured as follows. That is, in the table provided in the rotary table device, a table groove portion recessed in the radial direction of the bearing is formed on the entire circumference of the outer circumferential surface of the table. In addition, a coil base in which a coil is arranged is arranged so as to enter the table groove portion and follow the table groove portion. Furthermore, the coil is arranged on both surfaces of the above-described coil base.

[0033] According to this structure, compared with the rotary table device provided with the conventional motor (one-stage motor), two motors can be arranged without changing the dimensions of the radial direction and the circumferential direction of the rotary table. In addition, even if the motors are overlapped in two stages, the increase in the dimensions in the axial direction can be suppressed. Therefore, a rotary table device that is compact and can obtain the driving force from two motors is provided.

[0034] In the rotary table device, a first recess in which a first coil row is arranged can be formed on the first surface of the coil base, and a second recess in which a second coil row is arranged can be formed on the second surface of the coil base. According to this structure, the dimensions in the axial direction in the rotary table device can be further suppressed, and a more compact rotary table device is obtained.

[0035] In the rotary table device, the wall surface of the table that defines the table groove portion can include a first wall surface that faces the first surface of the coil base and a second wall surface that faces the second surface of the coil base. The first wall surface has a first table wall surface portion that is a recess, and the first magnet row is arranged in the first table wall surface portion. The second wall surface has a second table wall surface portion that is a recess, and the second magnet row is arranged in the second table wall surface portion. According to this structure, the dimensions in the axial direction in the rotary table device can be further suppressed, and a more compact rotary table device is obtained.

[0036] In the rotary table device, the table includes a first member including a plate-shaped portion and a second member including a plate-shaped portion that is stacked in the axial direction of the bearing with respect to the first member. In addition, the bearing is a cross roller bearing, and an outer ring of the cross roller bearing is sandwiched by the first member and the second member. According to this structure, the outer shell of the bearing is formed by the first member and the second member, and the outer ring of the bearing can be directly sandwiched and held by the first member and the second member. According to this structure, the processing and assembly of the rotary table device become easy. In addition, the bearing can be reliably held, and the driving force of the motor is used for the rotation without loss.

[0037] In the rotary table device, the bearing and the coil base can be at the same center position in the axial direction of the bearing. The bearing and the coil base being at the same center position in the axial direction of the bearing means that the bearing and the coil base are arranged at the same height when viewed in the horizontal direction. The rotary table device of the present disclosure has a motor on each of the two faces of the coil base, and the sum of the torques of the two motors becomes the driving force of the rotary table device. If the coil base and the bearing are arranged at the same height, the driving force of the rotary table device is not transmitted with eccentric load with respect to the bearing, and thus is preferable.

[0038] In the rotary table device, it can be configured to further include a first substrate fixed to the coil base between the first coil row and the first magnet row, and further include a second substrate fixed to the coil base between the second coil row and the second magnet row, the first coil row being fixed to the first substrate, and the second coil row being fixed to the second substrate. By arranging the substrate between the coil and the magnet, the interval between the coil and the magnet can be maintained. In addition, the upper surface of the recess of the coil base in which the coil is accommodated can be covered with the substrate. According to this structure, dust and the like can be prevented from entering the recess.

[0039] In the rotary table device, a drive circuit and a control circuit that controls the drive circuit are further included, and the first motor and the second motor can be electrically connected in parallel with respect to the drive circuit. According to this structure, the first motor and the second motor are controlled by one drive circuit, and the first motor and the second motor are simultaneously operated based on one signal (current). Therefore, the operations of the two motors do not deviate, and the sum of the torques generated by the two motors can be effectively utilized.

[0040] [Specific Examples of Embodiments]

[0041] Next, one example of a specific embodiment of the rotary table of the present disclosure will be described with reference to the drawings. In the following drawings, the same or equivalent parts are given the same reference numerals and the description thereof will not be repeated.

[0042] (Embodiment 1)

[0043] Figure 1 is a schematic perspective view showing the structure of the rotary table device in Embodiment 1. In Figure 1 , the Z-axis direction is the direction in which the rotation axis (rotation axis of the bearing) R of the table of the rotary table device extends. Figure 2 is a schematic sectional view showing the structure of the rotary table device, showing the state after cutting along the A-A line in Figure 1 . Figure 15 is a schematic plan view showing the structure of the rotary table device.

[0044] First, the schematic structure of the rotary table device 1 will be described.

[0045] Referring to Figure 1 , the rotary table device 1 in Embodiment 1 is provided with a base portion 10 as a fixed portion and a table 20 that can rotate with respect to the base portion 10. The base portion 10 includes a bed portion 40 as a support table, a support pillar 41 (41a to 41d) provided at the four corners of the bed portion, and a coil base 50 that is supported by the support pillars 41a to 41d and is fixed to the bed portion 40 via the support pillars 41a to 41d. The support pillars 41a to 41d are the same height as each other, and the coil base 50 is disposed horizontally. Referring to Figure 2 , in the rotary table device 1 in Embodiment 1, the base portion 10 and the table 20 are connected via a bearing 30. The bearing 30 is provided to the base portion 10. An inner ring 31 of the bearing 30 is fixed to the base portion 10, and an outer ring 32 of the bearing 30 is fixed to the table 20.

[0046] Referring to Figure 1 , Figure 2 , Figure 15 The schematic structure of the fixing of the inner ring 31 of the bearing 30 will be described. The base portion 10 includes, in addition to the above-described structure, a first central portion 42 that stands up from the bed portion 40 along a circular hole at the center of the bed portion 40, and a second central portion 43 that is continuous with the upper portion of the first central portion 42. The bed portion 40 and the first central portion 42 are fixed by a screw 45. The first central portion 42 and the second central portion 43 are fixed by a screw 46. The first central portion 42 is a substantially cylindrical member, but the outer periphery of the upper portion thereof is a recess, and constitutes the housing of the inner ring 31 of the bearing 30 by being combined with the lower surface of the second central portion 43. That is, the inner ring 31 of the bearing 30 is fixed by being sandwiched by the first central portion 42 and the second central portion 43. The bearing 30 is a cross roller bearing provided with rollers 33. In the bearing 30, a seal 34 is provided between the inner ring 31 and the outer ring 32. The fixing structure of the outer ring 32 of the bearing 30 will be described later.

[0047] Referring to Figure 1 , Figure 2 , Figure 15An annular upper baffle 91 is disposed on the upper part of the bearing 30. The gap between the inner ring 31 and the outer ring 32 of the upper part of the bearing 30 is covered by the upper baffle 91. The upper baffle 91 is fixed to the second central part 43 by screws 48. An annular lower baffle 92 is disposed on the lower part of the bearing 30. The gap between the inner ring 31 and the outer ring 32 of the lower part of the bearing 30 is covered by the lower baffle 92. The lower baffle 92 is fixed to the bed part 40 by screws 44. The upper part of the lower baffle 92 is formed with a slope that slopes downward from the upper end of the lower baffle 92 toward the center. By forming the lower baffle 92 in this shape, lubricant leaks from the bearing 30, and even when the lower baffle 92 receives lubricant, it is possible to prevent lubricant from entering the motor or other parts. The upper baffle 91 and the lower baffle 92 can be resin or steel components. It should be noted that if the bearing 30 has a seal 34, the upper baffle 91 and the lower baffle 92 can also be removed. Furthermore, if the upper baffle 91 and the lower baffle 92 are present, the seal 34 of the bearing 30 can also be removed. Consequently, both the seal 34 and the upper baffle 91 and the lower baffle 92 can be removed.

[0048] Reference Figure 2 On the entire circumference of the outer perimeter of the worktable 20, in the radial direction of the bearing 30 ( Figure 2 A recessed portion, known as a worktable groove 60, is formed on the XY direction of the worktable 20, extending from the outer periphery inward. A coil base 50 enters the worktable groove 60 and is arranged along the worktable groove 60. A coil 101 is disposed on the first surface 50a of the coil base 50. A magnet 201 is disposed on the wall surface 20a of the worktable 20, facing the coil 101. Furthermore, a coil 301 is disposed on the second surface 50b of the coil base 50. A magnet 401 is disposed on the wall surface 20b of the worktable 20, facing the coil 301.

[0049] Magnet 201 constitutes part of a first magnet column 200, which is a row of multiple magnets arranged along the rotational direction of bearing 30. Coil 101 constitutes part of a first coil column 100, which is a row of multiple coils arranged parallel to the first magnet column 200. The first coil column 100 and the first magnet column 200 constitute a first motor 150. Magnet 401 constitutes part of a second magnet column 400, which is a row of multiple magnets arranged along the rotational direction of bearing 30. Coil 301 constitutes part of a second coil column 300, which is a row of multiple coils arranged facing the second magnet column 400. The second coil column 300 and the second magnet column 400 constitute a second motor 350. That is, the rotary table device 1 includes both a first motor 150 and a second motor 350.

[0050] Next, the worktable 20 of the rotary worktable device 1 will be described in detail.

[0051] Figure 3 is a perspective view shown with the work table 20 removed. Figure 4 is a side view of the work table 20. Figure 5A is a sectional view of the work table 20. Figure 5B is a sectional view shown with the work table 20 and the bearing 30 removed.

[0052] With reference to Figure 3 , Figure 4 , the first member 21 and the second member 22 of the work table 20 are stacked in the axial direction (Z direction) of the rotary work table device. The first member 21 includes a substantially annular plate-shaped first annular portion 23, and a first cylindrical portion 24 of a cylindrical shape extending in the axial direction from the inner periphery of the first annular portion 23 downward. The second member 22 includes a substantially annular plate-shaped second annular portion 25, and a second cylindrical portion 26 of a cylindrical shape standing from the inner periphery of the second annular portion 25 and extending in the axial direction. The end face of the first cylindrical portion 24 and the end face of the second cylindrical portion 26 are in contact with each other. A threaded hole 27a is formed through the first annular portion 23 and the first cylindrical portion 24 in the first member 21. In Embodiment 1, 16 threaded holes 27a are formed at equal intervals in the circumferential direction. Further, a threaded hole 27b corresponding to the threaded hole 27a is formed in the end face of the second cylindrical portion 26 of the second member 22 in contact with the first cylindrical portion 24. Figure 6 The first member 21 and the second member 22 are fixed by inserting a screw through the threaded holes 27a and 27b and fastening. A fixing hole 730 for fixing a position scale is provided in the outer periphery of the second annular portion 25 of the second member 22.

[0053] With reference to Figure 4 , Fig. 5, the outer diameters of the first cylindrical portion 24 and the second cylindrical portion 26 are equal to each other. That is, the outer peripheral surface of the first cylindrical portion 24 and the outer peripheral surface of the second cylindrical portion 26 are the same plane. The work table groove portion 60 is formed by the difference between the outer diameters of the first annular portion 23 and the second annular portion 25 and the outer diameters of the first cylindrical portion 24 and the second cylindrical portion 26. The outer peripheral surface of the first cylindrical portion 24 and the outer peripheral surface of the second cylindrical portion 26 constitute the inner peripheral wall surface 60c that defines the work table groove portion 60. The wall surface 20a (Fig. 2) of the first annular portion 23 of the first member 21 on the side facing the coil base 50 constitutes the first wall surface 60a of the work table groove portion 60. The wall surface 20b (Fig. 2) of the second annular portion 25 of the second member 22 on the side facing the coil base 50 constitutes the second wall surface 60b of the work table groove portion 60. The work table groove portion 60 is an annular (hollow cylindrical) groove recessed inward from the outer peripheral surface of the work table 20 in the radial direction of the bearing. Figure 2 Figure 2

[0054] With reference to Figure 5A ​​The surface of the first member 21 on the side facing the second member 22 in the first annular portion 23, that is, the first wall surface 60a of the table groove portion 60 is formed with a ring-shaped recess 61 extending in the circumferential direction. Further, the surface of the second member 22 on the side facing the first member 21 in the second annular portion 25, that is, the second wall surface 60b of the table groove portion 60 is formed with a ring-shaped recess 62 extending in the circumferential direction and having the same diameter and depth as the recess 61. Further, a recess 28 recessed in the radial direction to the outside is formed on the inner peripheral side of the first cylindrical portion 24 and the second cylindrical portion 26. Referring to Figure 5B The outer ring 32 of the bearing 30 is held in the recess 28. That is, the recess 28 constitutes an outer case of the outer ring 32 of the bearing 30. The outer ring 32 is held by the first member 21 and the second member 22 of the table 20. Specifically, the outer ring 32 is fixed with respect to the table 20 by the fastening force of the screws 47 (see FIG. 2) fastening the first member 21 and the second member 22. In order to reliably fix the outer ring 32 and the table 20, in addition to the fixing based on the holding, adhesion using an adhesive or the like can be used. Further, a groove 29 in which the corners of the first member 21 and the second member 22 are chamfered is formed in the boundary portion of the first member 21 and the second member 22 in the recess 28. By chamfering the first member 21 and the second member 22, the bearing 30 can be easily inserted. Figure 1 、 Figure 15

[0055] Figure 6 is a perspective view showing only the second member 22 of the table 20. Figure 7 is a view showing the accommodation of the second member 22 and the second magnet row 400. Referring to Figure 6 、 Figure 7 The second member 22 includes a second annular portion 25 and a second cylindrical portion 26 that stands from the inner periphery of the second annular portion 25 and extends in the axial direction. The upper surface (the surface appearing in the drawing) of the second annular portion 25 constitutes the second wall surface 60b of the table groove portion 60. The ring-shaped recess 62 extending in the circumferential direction is formed in the second wall surface 60b.

[0056] ​In the recess 62, magnets 401 are arranged in a circumferential direction of rotation of the bearing. Each magnet 401 is a plate-shaped magnet with a generally trapezoidal facet converging towards the center of rotation. The depth of the recess 62 is approximately equal to the thickness of the magnets 401. That is, the magnets 401 are substantially contained within the recess 62, protruding only slightly from the surface of the worktable 20. Twenty-one magnets 401 arranged adjacent to each other constitute a second magnet column 400. The magnets 401 are arranged within approximately 315° of the full 360° circumference of the recess 62. A pin hole 620 is formed on the bottom surface of the recess 62. The pin hole 620 facilitates easy positioning of the starting point for arranging the magnets 401. In the second magnet column 400, the magnets 401 are arranged with alternating N and S poles. It should be noted that in Embodiment 1, the 21 magnets 401 of the second magnet array 400 are arranged at approximately 315°, but the number of magnets and their arrangement are not limited to this. For example, magnets can also be arranged around the entire circumference (360°) of the recess 62. The number of magnets and their arrangement can be appropriately changed depending on the size and performance of the magnets, the torque and rotational speed required by the motor, and other structures of the rotary table device (such as the configuration of limit sensors).

[0057] Figure 8 This is a perspective view showing only the first component 21 of the workbench 20. Figure 9 This diagram shows the storage of the first component 21 and the first magnet array 200. Most of the first component 21 is the same as the second component 22. Here, the main difference in structure is described. A limiter fixing portion 210 is formed at one edge of the first annular portion 23 of the first component 21. The limiter fixing portion 210 is formed as a recess. By forming the limiter fixing portion 210 as a recess, a fixing screw 211 (which will fix the limiter disposed on the lower surface of the first component 21) is used to fix the limiter. Figure 1 When inserted, the head of the fixing screw 211 will not protrude onto the surface of the worktable 20. Furthermore, the outer diameter of the first annular portion 23 of the first member 21 is slightly larger than the outer diameter of the second annular portion 25 of the second member 22. A threaded hole 9 is formed in the first annular portion 23, penetrating the first annular portion 23 along the thickness direction. In Embodiment 1, eight threaded holes 9 are provided at equal intervals in the circumferential direction, but this number is not particularly limited. The threaded holes 9 are used to mount the rotary worktable device 1 to workpieces or the like of other members. A threaded hole 27a is provided in the first cylindrical portion 24, penetrating the first member along the thickness direction. The threaded hole 27a corresponds to the threaded hole 27b of the second member 22. By inserting the screw 47 ( Figure 1 , Figure 15 ) Insert threaded holes 27a and 27b into the upper surface of the first component 21 and tighten them, thereby fixing the first component 21 and the second component 22 to each other.

[0058] Reference Figure 8、 Figure 9 The lower surface (a surface appearing in the drawing) of the first annular portion 23 constitutes a first wall surface 60a of the table groove portion 60. A recessed portion 61 extending in a ring shape in the circumferential direction is formed in the first wall surface 60a. The magnet 201 arranged in the circumferential direction of the bearing is disposed in the recessed portion 61. The 21 magnets 201 disposed adjacent to each other constitute a first magnet row 200. The structure of the first magnet row 200 is the same as that of the second magnet row 400. A pin hole 610 is formed in the bottom surface of the recessed portion 61, and the start positioning of the first magnet row 200 becomes easy. The first magnet row 200 and the second magnet row 400 are disposed at the same position in the circumferential direction of the rotary table device.

[0059] Next, the coil base 50 of the rotary table device 1 will be described in detail.

[0060] Figure 10 is a perspective view showing only the coil base 50. Figure 11 is a cross-sectional perspective view showing the state after the coil base 50 is cut off at the C-C line in Figure 10 The entire coil base 50 is a plate-shaped member made of steel. Referring to Figure 10 , a circular hole centered on the rotation axis R of the bearing (the rotation axis of the table 20) is formed in the center of the coil base 50. The peripheral wall 50d defining the circular hole is separated from and opposes the outer peripheral surface of the first cylindrical portion 24 of the table 20 and the outer peripheral surface of the second cylindrical portion 26, that is, the inner peripheral wall surface 60c (see Figure 4 ) defining the table groove portion 60. The diameter of the circle defined by the peripheral wall 50d is slightly larger than the diameter of the inner peripheral wall surface 60c of the table groove portion 60.

[0061] Referring to Figure 10 , threaded holes 58 for fixing the coil base 50 to the support column 41 are formed in the four corners of the coil base 50. The four corners of the coil base 50 are formed in an arc shape as a part of the arc of a circle centered on the rotation axis R. In addition, the coil base 50 has an expanded portion 55 protruding further outward than the quadrangle defined by the bed portion 40. Threaded holes 59 for inserting a screw for fixing the coil base 50 to the encoder head 710 (see Figure 1 ) are formed in the expanded portion 55.

[0062] Referring to Figure 10 , Figure 11 The coil base 50 has a first surface 50a and a second surface 50b. In Figure 10 , the first surface 50a of the coil base 50 is represented. A recessed portion extending in a ring shape in the circumferential direction of the rotation of the bearing, that is, a first recessed portion 51 is formed in the first surface 50a. Referring to Figure 11On the second surface 50b, an annular recess extending circumferentially along the rotation of the bearing, namely the second recess 52, is also formed. The first recess 51 and the second recess 52 have the same width and depth. Multiple fixing pins for fixing the coil are formed circumferentially on the bottom surface of the first recess 51. Figure 12 The insertion hole 57 extends from the first surface 50a to the second surface 50b, with the two holes arranged as a group. A pin is inserted into one of the two holes in the group from the first surface 50a, and into the other from the second surface 50b.

[0063] Figure 12 This is a perspective view showing the coil base 50 and the substrate removed. (Refer to...) Figure 10 , Figure 12 The first substrate 81 is disposed in contact with the first surface 50a of the coil base 50. The first substrate 81 is mounted such that it covers the entire circumference of the first recess 51. A coil is mounted on the surface of the first substrate 81 opposite to the coil base 50 (see reference). Figure 13 , Figure 14 The same applies to the second surface 50b. That is, the second substrate 82 ( Figure 2 The second substrate 81 is configured to contact the second surface 50b. The second substrate 82 is mounted to cover the entire circumference of the second recess 52. A coil is mounted on the surface of the second substrate 82 opposite to the coil base 50. With this structure, the coil is respectively housed in the first recess 51 and the second recess 52 provided on both sides of the coil base 50. The first substrate 81 and the second substrate 82 are, for example, printed circuit boards. Three wires corresponding to the U phase, V phase, and W phase are respectively connected to the first substrate 81 and the second substrate 82. The three wires supply the U phase, V phase, and W phase current to the first coil column 100 and the second coil column 300 mounted on the first substrate 81 and the second substrate 82, respectively. The first coil column 100 and the second coil column 300 are connected to the drive circuit 600 described later via the first substrate 81 and the second substrate 82.

[0064] Figure 13 as well as Figure 14 This is a three-dimensional view showing the substrate and coil after they have been removed. Figure 13 The side of the first substrate 81 opposite the worktable 20 is shown (see reference). Figure 2 ). Figure 14 The side of the first substrate 81 opposite the coil base 50 is shown. (Refer to...) Figure 14 On the surface of the first substrate 81, along its circumference, 12 coils 101 are arranged adjacent to each other. Each coil 101 is provided with a collar 110, and a fixing hole 111 is formed in the collar 110. The first coil array 100 passes through a hole 57 in the coil base 50 that passes through the fixing hole 111. Figure 10The first substrate 81 is fixed to the coil base 50 by a fixing pin (not shown) inserted in a manner that the fixing pin is inserted into a hole formed in the first substrate 81. The second substrate 82 is also the same structure, and the description thereof is omitted. An insulating film (not shown) is attached to the first substrate 81 and the second substrate 82.

[0065] Referring to Figure 14 , the coils 101 are flat and wound in a ring shape. Twelve coils 101 constitute the first coil row 100. The coils 101 are 3-phase coils, and in the first coil row 100, the coils are arranged in the order of U-phase, V-phase, and W-phase in this order from one end, and the arrangement is repeated. Note that in Embodiment 1, twelve coils are included in the coil row, and the number of coils included in the coil row and the arrangement can be changed according to the size of the motor and the required torque. Referring to Figure 2 、 Figure 14 , the first coil row 100 and the second coil row 300 are disposed on both surfaces of the coil base 50. The number of coils constituting the first coil row 100 and the second coil row 300 is equal to each other. In addition, in the first coil row 100 and the second coil row 300, the coils of the same phase can be arranged in such a manner that the coils are located at the same position in the circumferential direction. According to this structure, the directions of the torques output from the two motors can be made to coincide, and a larger torque can be obtained.

[0066] Next, the motor included in the rotary table device will be described in detail.

[0067] Referring to Figure 2 , the coils 101 are arranged on the first surface 50a of the coil base 50. The magnets 201 are arranged on the wall surface 20a of the table 20 in such a manner that the magnets 201 face the coils 101. As described above, the coils 101 constitute the first coil row 100, and the magnets 201 constitute the first magnet row 200. The first substrate 81 is interposed between the first coil row 100 and the first magnet row 200, and the first coil row 100 and the first magnet row 200 are separated from each other. The first coil row 100 and the first magnet row 200 constitute the first motor 150. The same applies to the second surface 50b of the coil base 50. That is, on the second surface side of the coil base, the second coil row 300 and the second magnet row 400 face each other, and constitute the second motor 350.

[0068] In the rotary table device 1 of the present disclosure, recesses are formed on both surfaces of the coil base 50, and the coil rows are accommodated in the recesses, respectively. In addition, the coil base 50 is arranged in such a manner that the coil base 50 enters the table groove portion 60 of the table 20. Further, a recess is provided on the surface of the table 20 that faces the coil base 50, and the magnet row is accommodated in the recess. According to this structure, even in the case where the motors are overlapped in two stages, the increase in the axial dimension can be suppressed, and a compact rotary table device can be realized.

[0069] Next, other structures will be described.

[0070] Referring to Figure 1 , Figure 15 Two limiters 220 are installed in two of the four corners of the coil base 50. Resin portions 222 are provided on the sides of the two limiters 220 facing each other. In addition, a limiter fixing portion 210 of the worktable 20 is located between the two limiters 220. A limiter opposed to the limiter 220 in the rotation direction is fixed to the lower portion of the limiter fixing portion 210. The two limiters 220 installed to the coil base 50 are fixed, and the limiter installed to the worktable rotates with the worktable. Excessive rotation of the worktable 20 is prevented by the limiter 220.

[0071] Referring to Figure 1 A scale 709 extending in the circumferential direction is attached to the outer peripheral side surface of the second member 22 of the worktable 20. Figure 16 The scale 709 is preferably provided at a portion corresponding to the back of the support 41a, 41b. An encoder head 710 is provided opposite the scale 709. When viewed from the outside of the rotary worktable device, dust adhesion and the like can be prevented by arranging the scale 709 behind the support. A signal line is wired to the encoder head 710. In addition, an electric wire for supplying three-phase current to the coils 101, 301 is provided.

[0072] Figure 16 is a schematic view showing the electrical connection of the rotary worktable device 1. In particular, the electrical connection of the first motor 150 and the second motor 350 is shown. Referring to Figure 16The rotary table device 1 includes a driver 700, a driving unit 410, a scale 709 mounted to the driving unit, and an encoder head 710 that detects the operation of the driving unit 410. The encoder head 710 is connected to a control circuit 500 described later. An encoder system 720 is configured by the scale 709 and the encoder head 710. The encoder system 720 is connected to the control circuit 500. The control circuit 500 controls a driving circuit 600 in accordance with an output signal of the encoder head 710. The driver 700 includes the control circuit 500 and the driving circuit 600. A power source not shown is connected to the driver 700. The control circuit 500 controls the driving circuit 600 in accordance with a program set in advance or a signal from the encoder head 710. The driving circuit 600 supplies currents corresponding to phases of U phase, V phase, and W phase, respectively. Electric wires L1, L2, and L3 are branched and connected to the first motor 150 and the second motor 350, respectively. That is, the first motor 150 and the second motor 350 are electrically connected in parallel with respect to the driving circuit 600. According to this structure, two motors are simultaneously operated by one driving circuit. Therefore, control for making the motors operate at the same frequency is not required, and the two motors can be reliably and easily operated, and torque from the two motors is obtained. The rotary table device 1 of the present disclosure is a direct drive type device that operates the first motor 150 and the second motor 350 by the currents from the driving circuit 600, and operates the table 20 by the generated torque.

[0073] The embodiments disclosed this time are illustrative in all points and are not limited by any of the aspects. The scope of the present invention is not limited by the above description, but is defined by the claims, and is intended to include all modifications within the meaning and range of equivalents of the claims.

[0074] BRIEF DESCRIPTION OF DRAWINGS

[0075] 1 rotary table device; 10 base portion; 20 table; 20a, 20b wall surface; 21 first member; 22 second member; 23 first annular portion; 24 first cylindrical portion; 25 second annular portion; 26 second cylindrical portion; 27a, 27b hole; 28 recess; 29 groove; 30 bearing; 31 inner ring; 32 outer ring; 33 roller; 34 seal; 40 bed portion; 41a-41d support; 42 first central portion; 43 second central portion; 44, 45, 46, 47, 48 screw; 50 coil base; 50a first surface; 50b second surface; 50d peripheral wall; 51 first recess; 52 second recess; 55 expansion portion; 57 hole; 58, 59 threaded hole; 60 table groove portion; 60a first wall surface; 60b second wall surface; 60c inner peripheral wall surface; 61, 62 recess; 610, 620 pin hole; 81 first substrate; 82 second substrate; 91 upper baffle; 92 lower baffle; 100 first coil row; 101 coil; 110 thimble; 111 fixing hole; 150 first motor; 200 first magnet row; 201 magnet; 210 position limiter fixing portion; 211 fixing screw; 220 position limiter; 222 resin portion; 300 second coil row; 301 coil; 350 second motor; 400 second magnet row; 401 magnet; 410 drive unit; 500 control circuit; 600 drive circuit; 700 driver; 709 scale; 710 encoder head; 720 encoder system; 730 fixing hole; L1, L2, L3 electric wire.

Claims

1. A rotary table device, wherein, have: abutment part; A bearing is disposed on the base portion; The worktable is supported by the bearing in a manner that allows it to rotate relative to the base portion; and The motor causes the worktable to rotate relative to the base portion in the rotational direction of the bearing. On the worktable, a radially recessed groove is formed in a ring shape on the outer circumference of the entire worktable surface, extending towards the bearing. The base portion includes an annular coil base, which is configured to enter and follow the worktable groove. The motor includes a first motor and a second motor. The first motor includes: The first magnet array is a column of multiple magnets arranged along the rotational direction of the bearing on the wall surface defining the worktable slot; and The first coil column is a column of coils arranged facing the first magnet column on the first surface of the coil base. The second motor includes: The second magnet array is a column of multiple magnets arranged along the rotational direction of the bearing on the wall surface defining the worktable slot; and The second coil array is a column of coils arranged axially along the bearing on a second surface of the coil base, opposite to the first surface, facing the second magnet array. The wall surface defining the workbench groove includes: The first wall surface faces the first surface of the coil base; The second wall faces the second surface of the coil base. The first wall surface has a first worktable wall surface portion that serves as a recess, and the first magnet array is disposed within the first worktable wall surface portion. The second wall has a second worktable wall portion that is a recess, and the second magnet array is disposed within the second worktable wall portion.

2. The rotary table device as described in claim 1, wherein, A first recess, in which the first coil row is disposed, is formed on the first surface of the coil base. A second recess, in which the second coil array is disposed, is formed on the second surface of the coil base.

3. The rotary table device as described in claim 1 or 2, wherein, The worktable includes a first member comprising a plate-like portion and a second member comprising a plate-like portion, which is stacked axially relative to the first member in the bearing.

4. The rotary table device as described in claim 3, wherein, The bearing is a cross roller bearing, and the outer ring of the cross roller bearing is clamped by the first component and the second component.

5. The rotary table device as described in claim 1 or 2, wherein, The bearing and the coil base are at the same center position in the axial direction of the bearing.

6. The rotary table apparatus as described in claim 1 or 2, wherein, A first substrate fixed to the coil base is also provided between the first coil array and the first magnet array. A second substrate fixed to the coil base is also provided between the second coil column and the second magnet column. The first coil array is fixed to the first substrate, and the second coil array is fixed to the second substrate.

7. The rotary table apparatus as described in claim 1 or 2, wherein, It also includes a drive circuit and a control circuit for controlling the drive circuit. The first motor and the second motor are electrically connected in parallel with respect to the drive circuit.

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