JP2014161988A - Rotary table device and machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a rotary table device that can prevent loosening of a positioning screw for stopping a rotary table at a predetermined indexing position; and a machine tool.SOLUTION: Pitch of a screw thread of a second male screw portion 103 of a first positioning screw 100 is smaller than pitch of a screw thread of a first male screw portion 102. That is, the pitch of the screw thread of the first male screw portion 102 is larger than pitch of the screw thread of the second male screw portion 103. Therefore, when the first male screw portion 102 rotates as much as the second male screw portion 103 rotates, the first male screw portion 102 moves toward a rear end portion 106 more than the second male screw portion 103. This can cause tension A to act on between an end portion 105 and a rear end portion 106 of a shaft portion 101 of the first positioning screw 100, preventing the first positioning screw 100 from loosing.

Description

  The present invention relates to a rotary table device and a machine tool including the rotary table device.

  The machine tool includes a rotary table device. The rotary table device disclosed in Patent Document 1 includes a base, a spindle, and a rotary table. The spindle is rotatably provided in the base. The rotary table rotates integrally with the spindle. The rotary table holds the workpieces on both sides of the upper surface. The machine tool processes a workpiece held on one of the upper surfaces of the rotary table. The rotary table rotates 180 degrees when processing of the workpiece held on one of the upper surfaces is completed. The machine tool starts machining another workpiece held on the other upper surface of the rotary table.

  Positioning accuracy of the rotary table is important for machining with high accuracy by machine tools. As the positioning device, the rotary table device is positioned by colliding a stopper piece of the rotary table and a positioning member of the base. To stop the rotary table at a predetermined position, it is necessary to adjust the stopper piece. If a screw is used for the stopper piece, the position adjustment becomes easy. However, since the stopper piece is repeatedly impacted, the screw may loosen due to vibration. As a measure against the loosening of the screw, it is conceivable to fix the stopper piece with the nut and then fix the nut flange to the rotary table side with the screw to prevent the rotation of the nut.

JP 2004-142081 A

  However, when the workpiece is processed, the stopper piece is always subjected to the clamp load of the rotary table, so that the screw of the stopper piece is loosened by the vibration of the workpiece processing. In this case, there is a problem that the stopper piece is pushed and the rotary table rotates and moves in the load direction. Therefore, there is a problem that the processing accuracy is lowered.

  The objective of this invention is providing the rotary table apparatus and machine tool which can prevent the loosening of the positioning screw which stops a rotary table in a predetermined index position.

  According to a first aspect of the present invention, there is provided a rotary table device comprising: a base; a spindle rotatably provided in the base and having an axis; a rotary table provided at an end of the spindle; and the spindle provided in the base. In the rotary table device provided with a rotating mechanism that rotates, a contact portion provided on the base side, a positioning screw for positioning the rotary table with an end portion in contact with the contact portion, and the rotary table A first through-hole through which the positioning screw passes, and a nut portion that fixes the other end side of the positioning screw opposite to the end to the rotary table side, A first male screw portion formed on the other end side, and a second male screw portion formed on the end side from the first male screw portion and having a screw pitch smaller than that of the first male screw portion. The nut portion includes a first female screw portion into which the first male screw portion is screwed, and a second through hole through which a fixing screw for fixing the nut portion to the rotary table side passes. The hole is characterized in that the second male screw part is screwed and a second female screw part having a smaller screw pitch than the first female screw part is provided.

  The positioning screw of the rotary table device has a first male screw part and a second male screw part whose screw pitch is smaller than that of the first male screw part. The amount of movement in the direction of the other end is greater at the first male screw than at the second male screw. Therefore, the tension between the first male screw portion and the second male screw portion of the first positioning screw is recovered, and the first positioning screw can be prevented from being loosened.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the rotary table side is provided with a fixing screw hole into which the fixing screw is screwed, and the second through hole. The fixing screw penetrates, and the fixing screw is screwed into the fixing screw hole so that the nut portion is fixed to the rotary table side. Therefore, it can be fixed to the rotary table side so that the nut portion does not loosen.

  A rotary table device according to a third aspect of the invention is characterized in that, in addition to the configuration of the invention according to the first or second aspect, a cover portion that covers the nut portion is provided. Therefore, it is possible to prevent the cutting fluid from entering the nut portion by the cover portion and loosening the nut portion.

  In addition to the configuration of the invention according to any one of claims 1 to 3, the rotary table device of the invention according to claim 4 is provided with a plurality of the second through holes in the nut portion, and It is a long hole formed in the shape of an arc centering on an axis, and at least one of the fixing screw holes is formed with respect to one second through hole. Therefore, the nut portion is fixed to the rotary table side so as not to loosen at any rotation angle.

  According to a fifth aspect of the present invention, there is provided a machine tool including the rotary table device according to any one of the first to fourth aspects. Since the machine tool includes the rotary table device according to any one of claims 1 to 4, the effect according to any one of claims 1 to 4 can be obtained.

The perspective view of the machine tool 50. FIG. The top view of the rotary table apparatus 1. FIG. FIG. 3 is a perspective view of the rotary table device 1. The left view of the rotary table apparatus 1. FIG. The partial enlarged view of the left side surface of the turntable apparatus 1. FIG. FIG. 3 is a cross-sectional view in the direction of arrows X-X in FIG. 2. The perspective view of the state which removed the turntable 10 of the turntable apparatus 1. FIG. FIG. 4 is a cross-sectional view taken along line XI-XI in FIG. 3. FIG. 3 is a longitudinal sectional view of the positioning screw 100. The fragmentary longitudinal cross-section of the 1st external thread part 102. FIG. The fragmentary longitudinal cross-section of the 2nd external thread part 103. FIG. The enlarged view of the nut part 120. FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 3, 4, 8, and 12 show a state in which the cover portion 144 is removed for explanation. The structure of the machine tool 50 will be described with reference to FIG. The machine tool 50 includes a base portion 52, a machine body 53, a protective cover 55, a control box 56, and the turntable device 1. The base unit 52 is a base of the machine tool 50. The machine body 53 is provided behind the upper surface of the base portion 52. The machine body 53 cuts a workpiece (not shown). The protective cover 55 is provided on the upper portion of the base portion 52. The protective cover 55 surrounds the machine main body 53. The protective cover 55 prevents chips and cutting fluid splashes from the machine body 53 from being scattered outside the machine body 53. The control box 56 is provided on the back surface of the protective cover 55. The control box 56 stores a numerical control device (not shown). The numerical controller controls the operation of the machine tool 50 based on an NC program stored in a memory (not shown). The turntable device 1 is provided in front of the upper surface of the base portion 52.

  The structure of the machine body 53 will be described. The machine body 53 includes a main base 63, a column 58, a main spindle head 59, a main spindle 60, and an automatic tool changer 65. The main stand 63 is provided behind the upper surface of the base portion 52. The column 58 is provided so as to be movable on the main base 63 in the X-axis direction and the Y-axis direction. The spindle head 59 can move in the Z-axis direction along the front surface of the column 58. The main shaft 60 is provided below the main shaft head 59. The spindle 60 is equipped with a tool (not shown) and rotates at a high speed by driving the spindle motor 62. The machine tool 50 cuts the workpiece by relative movement between the tool mounted on the spindle 60 and the workpiece held on the rotary table 10 of the rotary table device 1. The automatic tool changer 65 is provided in the vicinity of the spindle head 59. The automatic tool changer 65 exchanges the tool mounted on the spindle 60 with another tool based on the NC program tool change command.

  The turntable device 1 has a turntable 10 at the top. The turntable 10 is formed in a rectangular shape in plan view and can reciprocate between a 0 degree position and a 180 degree position. The rotary table 10 can hold a workpiece on one end side and the other end side in the longitudinal direction. While the machine tool 50 is machining the workpiece held on one end side of the turntable 10, the operator can remove the worked workpiece held on the other end side and attach an unmachined workpiece.

  The structure of the rotary table device 1 will be described with reference to FIGS. As shown in FIGS. 2 and 3, the turntable device 1 includes a base 2, a turntable 10, and a clamp mechanism 19 (see FIG. 7).

  As shown in FIG. 3 and FIG. 4, the base 2 is a rectangular parallelepiped metal base. As shown in FIGS. 6 and 7, the base 2 includes a bearing 4, an outer bearing retainer 15, an inner bearing retainer 16, seal members 17 and 18, a large gear 5, and a drive motor 7 (see FIG. 7). The bearing 4 has a substantially ring shape in plan view. The bearing 4 is disposed so as to surround the outer periphery of the spindle 3. The outer peripheral surface of the spindle 3 slides along the rolling surface of the bearing 4. Therefore, the bearing 4 can rotatably support the spindle 3.

  Both the outer bearing retainer 15 and the inner bearing retainer 16 have a ring shape in plan view. The outer bearing retainer 15 has a larger diameter than the inner bearing retainer 16. The inner bearing retainer 16 is located inside the outer bearing retainer 15. The outer bearing retainer 15 and the inner bearing retainer 16 press the bearing 4 from above to the base 2 side. The inner bearing retainer 16 is fixed to the spindle 3 with a plurality of screws. The outer bearing retainer 15 is fixed to the base 2 with a plurality of screws. The seal members 17 and 18 are inserted between the circumferential lower surface groove of the rotary table 10 and the circumferential upper surface groove of the base 2 on the upper and lower surfaces of the outer bearing retainer 15.

  As shown in FIG. 6, the cavity 2 </ b> A is provided at the center inside the base 2 and the upper part is opened. The large gear 5 is provided in the cavity 2A. The large gear 5 has an axis line in the vertical direction, is fitted to the lower part of the spindle 3, and is fixed to the spindle 3 with a plurality of bolts (not shown). The bolt is inserted from the upper surface of the rotary table 10. Therefore, the large gear 5 rotates integrally with the spindle 3 and the rotary table 10.

  As shown in FIG. 7, the drive motor 7 is disposed outside the base 2. The drive motor 7 rotationally drives a drive shaft (not shown). The drive shaft penetrates the base 2 horizontally and has a tip portion located in the cavity 2A. The drive shaft is provided with a gear (not shown) at the tip. The gear (not shown) meshes with a tooth portion (not shown) formed at the lower portion of the large gear 5. Therefore, when the drive motor 7 is driven, the rotary table 10 rotates through the drive shaft, the gear, the large gear 5 and the spindle 3.

  The turntable 10 is provided on the base 2. As shown in FIGS. 2 and 3, the rotary table 10 has grooves 12 and 13 formed on the left and right sides of the upper surface (upper and lower sides in FIG. 2). The grooves 12 and 13 are used to fix the workpiece directly or indirectly through a jig. As shown in FIG. 3, the rotary table 10 has a lower cover body 14 attached to the lower surface. The lower cover body 14 covers the outer side of the base 2 on the lower surface of the rotary table 10.

  The positioning mechanism of the rotary table 10 will be described with reference to FIGS. The rotary table device 1 can position the rotary table 10 at the index positions of the 0 degree position and the 180 degree position, respectively. As shown in FIG. 7, the base 2 includes a first contact portion 21A and a second contact portion 21B on the outer surface. The first contact portion 21A and the second contact portion 21B are rectangular parallelepiped members, and are fixed to the side surface of the base 2 with bolts or the like so as to be symmetric.

  On the other hand, as shown in FIGS. 3, 4, 5, 7, and 8, the rotary table 10 includes a first positioning screw 100 and a second positioning screw 200 on the lower surface side. In the first positioning screw 100, when the rotary table 10 is rotated counterclockwise (in the direction of arrow B in FIG. 2), the tip end portion 105 contacts the first contact portion 21A (see FIGS. 7 and 8). The rotary table 10 is positioned at a predetermined index position. When the rotary table 10 is rotated clockwise (in the direction of the arrow A in FIG. 2), the second positioning screw 200 is in contact with the second contact portion 21B and the rotary table 10 at a predetermined index position. Positioning. In the present embodiment, the rotary table 10 is rotated 180 degrees clockwise and counterclockwise. Therefore, the operator can attach the unprocessed workpiece by removing the processed workpiece on the other end side while processing the workpiece on the upper surface one end side of the turntable 10.

  With reference to FIGS. 8-12, the detail of the structure of the 1st positioning screw 100 and the 21st contact part 21A is demonstrated. As shown in FIGS. 8 and 9, the first positioning screw 100 includes a columnar shaft portion 101 and passes through the first through hole 147 of the positioning screw holding portion 140 provided on the lower surface of the rotary table 10. The distal end portion 105 of the shaft portion 101 of the first positioning screw 100 contacts the first contact portion 21A.

  The shaft portion 101 of the first positioning screw 100 includes a first male screw portion 102 on the rear end portion 106 side. The shaft portion 101 of the first positioning screw 100 includes a second male screw portion 103 on the tip portion 105 side. The thread pitch P2 of the second male thread part 103 shown in FIG. 11 is smaller than the thread pitch P1 of the first male thread part 102 shown in FIG. The rear end portion 106 of the first positioning screw 100 is provided with a hexagonal hole 104. The first set screw 100 can be rotated by fitting a hexagon stick wrench (not shown) into the hexagon hole 104. The front end portion 105 corresponds to the “end portion”, and the rear end portion 106 corresponds to the “other end portion”.

  A nut portion 120 is screwed into the first male screw portion 102 of the first positioning screw 100. The nut portion 120 includes a first female screw portion 121 at a position corresponding to the first male screw portion 102. Further, the first through hole 147 of the positioning screw holding part 140 includes a second female screw part 148 at a position facing the second male screw part 103. The thread pitch P2 of the second female thread part 148 shown in FIG. 11 is smaller than the thread pitch P1 of the first female thread part 121 shown in FIG. The second positioning screw 200 that contacts the second contact portion 21 </ b> B has the same structure as the first positioning screw 100. That is, as shown in FIG. 7, the shaft portion 201 of the second positioning screw 200 includes a first male screw portion 202. The shaft portion 201 of the second positioning screw 200 includes a second male screw portion 203 on the tip portion 205 side. The thread pitch of the second male thread portion 203 is smaller than the thread pitch of the first male thread portion 202.

  Next, the structure of the nut portion 120 will be described with reference to FIGS. 4, 5, 9, and 12. The nut portion 120 includes a flange portion 122 and a hex nut 123. The flange portion 122 and the hexagon nut 123 have an integral structure. As shown in FIG. 9, the hexagon nut 123 includes a first female screw portion 121 on the inner side. Therefore, the hex nut 123 is screwed into the first male screw portion 102 on the rear end portion 106 side of the first positioning screw 100. In addition, the flange portion 122 includes second through holes 124, 125, and 126 through which fixing screws 130 that fix the nut portion 120 to the positioning screw holding portion 140 of the rotary table pass, respectively. The second through holes 124, 125, 126 are provided at equiangular intervals with the axis of the shaft portion 101 as the center. Each of the second through holes 124, 125, and 126 is an arc-shaped long hole centered on the axis of the shaft portion 101. The side surface 141 of the positioning screw holding portion 140 includes six fixing screw holes 142 into which the fixing screw 130 is screwed, with an interval of 60 degrees centering on the axis of the shaft portion 101. In the state shown in FIG. 12, two fixing screw holes 142 formed on the side surface 141 of the positioning screw holding part 140 are exposed from the second through hole 124. That is, when the fixing screw hole 142 is exposed on one end side of the second through hole 124, another fixing screw hole 142 is exposed on the other end side of the second through hole 124. The second through holes 125 and 126 are the same as the second through hole 124. The number of fixing screw holes 142 is six, but three fixing screws 130 are used. Each one fixing screw 130 passes through the second through holes 124, 125, 126 and is screwed into each fixing screw hole 142. Therefore, the nut portion 120 is fixed to the side surface 141 of the positioning screw holding portion 140 so as not to loosen.

  As shown in FIG. 5, the cover portion 144 covers the nut portion 120. The cover portion 144 is a substantially rectangular member that is open on three sides, has three flat surfaces, and is viewed from the front. As shown in FIG. 12, the positioning screw holding portion 140 includes a fixing portion 145 that is an inverted L-shaped rib that fixes the cover portion 144. The fixing portion 145 includes two screw holes 146 into which the fixing screw 143 is screwed. A fixing screw 143 is screwed into each screw hole 146 to fix the cover portion 144. The mounting portion of the second positioning screw 200 has the same structure, and the nut portion 220 has the same structure as the nut portion 120.

  Next, a method for attaching and adjusting the first positioning screw 100 will be described. First, as shown in FIG. 9, the first positioning screw 100 is inserted into the first through hole 147. At this time, the nut portion 120 is not yet attached. A hexagon wrench (not shown) is inserted into the hexagon hole 104 of the rear end portion 106 of the first positioning screw 100 and the first positioning screw 100 is rotated so that the second male screw portion 103 is the second through hole 147. Screwed into the female thread portion 148. The amount of protrusion of the tip portion 105 of the first positioning screw 100 is adjusted to adjust the contact state between the tip portion 105 and the first contact portion 21A. By this adjustment, the rotary table 10 is positioned at a predetermined index position.

  When the protruding amount of the front end portion 105 increases, the rotary table 10 rotates in the clockwise direction (the direction of arrow A shown in FIG. 2). Further, when the protruding amount of the front end portion 105 decreases, the rotary table 10 rotates in the counterclockwise direction (the direction of arrow B shown in FIG. 2). By this adjustment, when the rotary table 10 stops at a desired index position, the nut portion 120 is screwed into the first male screw portion 102 of the first positioning screw 100. In a state where the nut portion 120 is in contact with the side surface 141 of the positioning screw holding portion 140, as shown in FIG. 12, each one fixing screw 130 passes through the second through holes 124, 125, 126 and is fixed to each other. Screwed into the screw hole 142. In this state, the nut portion 120 is fixed to the side surface 141 of the positioning screw holding portion 140. In this state, the rear end portion 106 is pulled in the left direction in FIG. 9, and therefore, as shown in FIG. 9, between the front end portion 105 and the rear end portion 106 of the shaft portion 101 of the first positioning screw 100. The first set screw 100 is prevented from being loosened by the tension A.

  In the case of the second positioning screw 200, the second positioning screw 200 is rotated in the same manner as the mounting and adjusting method of the first positioning screw 100 with the rotary table 10 rotated 180 degrees from the position adjusted above. The amount of protrusion of the tip end portion 205 of 200 is adjusted to adjust the contact state between the tip end portion 205 and the second contact portion 21B. With this adjustment, when the rotary table 10 stops at a desired index position, the nut portion 220 is screwed into the first male screw portion 202 of the second positioning screw 200. Thereafter, the nut portion 220 is fixed in the same manner as the nut portion 120. In this state, tension acts between the front end portion 205 and the rear end portion 206 of the shaft portion 201 of the second positioning screw 200 to prevent the second positioning screw 200 from loosening.

  The clamp mechanism 19 will be described with reference to FIG. The clamp mechanism 19 is a mechanism that clamps the rotary table 10 and fixes (locks) the rotary table 10 at index positions of 0 degree position and 180 degree position. The clamp mechanism 19 includes a first clamp block 33A, a second clamp block (not shown) support block 36, a support shaft 37, a clamp arm 38, a bracket 40, a cam follower 34, an air cylinder 35, an air cylinder shaft 35A, and a compressor (not shown). ), A solenoid valve (not shown) and the like.

  Next, the operation of the rotary table device 1 having the above configuration will be described with reference to FIGS. 3, 9, 10 and 11. Each time processing of the work held on one end of the turntable 10 is completed, the turntable 10 is rotated 180 degrees clockwise (in the direction of arrow A in FIG. 3) or counterclockwise (in the direction of arrow B in FIG. 3). Repeat the rotation. At this time, the front end portion 105 of the first positioning screw 100 comes into contact with the first contact portion 21A and stops at a predetermined index position. Further, the distal end portion 205 of the second positioning screw 200 comes into contact with the second contact portion 21B and stops at a predetermined index position. This operation is repeated.

  Here, the tension A acting between the front end portion 105 and the rear end portion 106 of the shaft portion 101 of the first positioning screw 100 due to the vibration of the front end portion 105 of the first positioning screw 100 coming into contact with the first contact portion 21A. May become weaker. In this case, as shown in FIG. 9, when an impact load or a clamp load due to contact with the first contact portion 21 </ b> A acts on the tip portion 105 of the shaft portion 101 in the arrow B direction, Power works. In this case, as shown in FIG. 11, the screw surface 103 </ b> A of the second male screw portion 103 contacts the screw surface 148 </ b> A of the second female screw portion 148. Then, since the second male screw portion 103 is screwed into the second female screw portion 148, the shaft portion 101 is acted on by a force that rotates the shaft portion 101 clockwise around the axis when viewed from the front end portion 105 side. Since the second male screw portion 103 is connected to the first male screw portion 102 via the shaft portion 101, the shaft portion 101 is also rotated clockwise around the axis when viewed from the front end portion 105 side. Power works.

  In the present embodiment, the thread pitch P2 of the second male thread portion 103 shown in FIG. 11 is smaller than the thread pitch P1 of the first male thread portion 102 shown in FIG. That is, the pitch P1 of the thread of the first male screw portion 102 is larger than the pitch P2 of the screw thread of the second male screw portion 103. Therefore, when the first male screw portion 102 rotates by the same amount as the rotation amount of the second male screw portion 103, the movement amount in the rear end portion 106 side is such that the first male screw portion 102 is more than the second male screw portion 103. large. Therefore, as shown in FIG. 10, the screw surface 102 </ b> A of the first male screw portion 102 contacts the screw surface 121 </ b> A of the first female screw portion 121. In this state, as shown in FIG. 9, sufficient tension A acts between the front end portion 105 and the rear end portion 106 of the shaft portion 101 of the first positioning screw 100, and the first positioning screw 100 is loosened. Is prevented. The same applies to the second positioning screw 200.

  Further, in the present embodiment, each one fixing screw 130 passes through the second through holes 124, 125, 126 and is screwed into each fixing screw hole 142. Therefore, the nut portion 120 is fixed to the side surface 141 of the positioning screw holding portion 140 so as not to loosen.

  In the present embodiment, the nut portion 120 is covered by the cover portion 144. Therefore, it is possible to prevent the cutting fluid from entering the nut portion 120 and loosening the nut portion 120.

  In the present embodiment, the second through holes 124, 125, 126 are each a long hole formed in an arc-shaped hole centered on the axis of the shaft portion 101. Further, two fixing screw holes 142 formed on the side surface 141 of the positioning screw holding part 140 are exposed from the second through hole 124. Each one fixing screw 130 passes through the second through holes 124, 125, 126 and is screwed into each fixing screw hole 142. Therefore, the nut portion 120 is fixed to the side surface 141 of the set screw holding portion 140 so as not to loosen at any rotation angle.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above-described embodiment, three second through holes are provided, but any number of second through holes, such as two, four, and five, can be provided. Further, although six fixing screw holes 142 are provided on the side surface 141 of the positioning screw holding portion 140, the number is not necessarily limited to six. Even if the nut portion 120 is rotated, it is sufficient if the fixing screw hole 142 is provided at a position that is surely opposed to the second through hole, and one may be provided for each second through hole. Further, the size of the pitch P2 of the thread of the second male screw portion 103 shown in FIG. 11 and the size of the pitch P1 of the screw thread of the first male screw portion 102 shown in FIG. 10 should be smaller than the pitch P1. The pitch difference may be determined by testing as appropriate.

DESCRIPTION OF SYMBOLS 1 Rotary table apparatus 2 Base 3 Spindle 10 Rotary table 19 Clamp mechanism 50 Machine tool 100 1st positioning screw 101 Shaft part 102 1st male screw part 103 2nd male screw part 103A Thread surface 104 Hexagonal hole 105 Tip part 106 Rear end part 120 Nut Part 121 first female thread part 122 flange part 123 hex nut 124, 125, 126 second through hole 140 positioning screw holding part 141 side face 142 fixing screw hole 143 fixing screw 144 cover part 145 fixing part 146 hole 147 first through hole 148 first Two female screw portions 148A Thread surface 201 Shaft portion 202 First male screw portion 203 Second male screw portion 205 Tip portion 220 Nut portion

Claims (5)

In a rotary table device comprising a base, a spindle having an axis provided rotatably in the base, a rotary table provided at an end of the spindle, and a rotary mechanism provided in the base for rotating the spindle,
A contact portion provided on the base side;
A positioning screw for positioning the rotary table with an end portion in contact with the contact portion;
A first through hole provided on the rotary table side through which the positioning screw passes;
A nut portion that fixes the other end side of the positioning screw opposite to the end portion to the rotary table side,
The set screw is
A first male screw portion formed on the other end side;
A second male screw portion formed on the end side from the first male screw portion and having a smaller screw pitch than the first male screw portion;
The nut portion is
A first female thread part into which the first male thread part is screwed;
A second through hole through which a fixing screw for fixing the nut portion to the rotary table side passes,
The rotary table device according to claim 1, wherein the first through-hole includes a second female screw portion in which the second male screw portion is screwed and the pitch of the screw is smaller than that of the first female screw portion. On the rotary table side, a fixing screw hole into which the fixing screw is screwed is provided,
The fixing screw passes through the second through hole, and the fixing screw is screwed into the fixing screw hole so that the nut portion is fixed to the rotary table side. The rotary table device as described.   The rotary table device according to claim 1, further comprising a cover portion that covers the nut portion. The second through hole is a long hole provided in the nut portion and formed in an arc shape centering on the axis of the positioning screw,
4. The rotary table device according to claim 1, wherein at least one fixing screw hole is formed with respect to one second through hole. 5.   A machine tool comprising the rotary table device according to claim 1.

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