Chucking method and rotary chucking device

Abstract

To provide a chucking method capable of chucking a brittle material or a large-sized rotary body having large elasticity being mounted on a rotary main spindle of a lathe or the like.SOLUTION: A chucking method includes: demagnetizing a claw feed motor 46; inserting a driving coupler 47 in a freely rotatable state into a driven coupler 49, to couple the driving coupler 47 to the driven coupler 49; exciting the claw feed motor 46; rotating the claw feed motor 46, moving a plurality of claws 63 in conjunction with each other via the driving coupler 47 and the driven coupler 49 to chuck and un-chuck a workpiece 3; and pulling out the driving coupler 47 from the driven coupler 49 to separate the driving coupler 47 and the driven coupler 49 from each other.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a chucking method and a rotary chuck device. [Background technology]

[0002] A fixing device for a thin-walled cylindrical object is known which includes a table, a first screw feed device which is arranged on the table and which moves radially at the same speed to contact three or more inner chucks which are arranged on the inner diameter side of the thin-walled cylindrical object, and a second screw feed device which presses an outer chuck opposite the inner chucks from the outer periphery side of the cylindrical object (JP Patent Publication No. 57-163003, hereinafter referred to as Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0003] The fixing device in Patent Document 1 does not rotate. Furthermore, when fixing a brittle material or a large rotating body with high elasticity, the rotating body may undergo brittle fracture or deformation. The present invention provides a chucking method and a rotary chuck device that can chuck brittle materials and large rotating bodies with high elasticity by mounting them on a rotating spindle of a lathe or the like.

[0004] The first aspect of the present invention is Demagnetize the jaw feed motor, Inserting the driving coupler, which is in a freely rotatable state, into the driven coupler to connect the driving coupler and the driven coupler; Exciting the pawl feed motor; Rotating the jaw feed motor to move the jaws in an interlocking manner via the driving coupler and the driven coupler to chuck and unchuck the workpiece; Pulling the driving coupler out from the driven coupler to separate the driving coupler and the driven coupler; This is a chucking method.

[0005] A second aspect of the present invention is A rotating frame supported so as to be rotatable about a rotation axis; a central bevel gear supported within the rotating frame so as to be rotatable about the rotation axis; a driven coupler connected to the central bevel gear; a driving coupler that moves forward and backward in a radial direction of the rotating frame, the driving coupler being connected to the driven coupler when moving forward in the direction of the rotation axis and being separated from the driven coupler when moving backward from the rotation axis; a pawl feed motor connected to the driving coupler; A plurality of claw units arranged on the rotating frame rotationally symmetrically about the rotation axis, each of the claw units comprising: a slider having a claw base and reciprocating in a radial direction of the rotating frame; a feed screw having a driven bevel gear meshing with the central bevel gear, extending along a radial direction of the rotating frame, and feeding the slider; having A control device, a storage device that stores an upper limit speed that is an upper limit of the rotation speed of the pawl feed motor and a clamp completion threshold value that is smaller than an upper limit of the torque of the pawl feed motor; a power supply control means for demagnetizing the pawl feed motor when the driving coupler is advanced to connect with the driven coupler; a jaw feed control means for controlling the jaw feed motor so that the rotation speed of the jaw feed motor is kept below the upper limit speed when the jaw base is fed during chucking, and the jaw feed motor is stopped when the torque of the jaw feed motor becomes equal to or greater than the clamp completion threshold value; A control device having The rotary chuck device has a

[0006] The rotary chuck device may include a sub-shaft that is disposed coaxially with the main shaft within the rotary frame and supported rotatably relative to the rotary frame, and a central bevel gear that is fastened to the main shaft.

[0007] The jaws are fed at a high feed rate related to the upper limit speed until they come into contact with the workpiece. The high feed rate is a feed rate at which the workpiece is not deformed or damaged when the jaws come into contact with the workpiece. At this time, the torque of the jaw feed motor is a small torque related to the resistance of the drive unit that moves the jaws. Small torque means that the torque is small compared to the torque after the jaws come into contact with the workpiece. When the jaws come into contact with the workpiece, the jaw speed gradually decreases. The jaw speed approaches 0. Also, when the jaws come into contact with the workpiece, the torque of the jaw feed motor gradually increases. The torque of the jaw feed motor reaches the upper limit torque.

[0008] The rotary chuck device may have a claw arranged on the claw base and having a contact portion made of an elastic material.

[0009] The rotor may further include a drive shaft having a drive bevel gear that meshes with the central bevel gear, connected to the driven coupler, and rotatably disposed within the rotating frame.

[0010] The rotary chuck device may include a drive shaft having a drive bevel gear and a driven coupler. The drive shaft extends radially. The drive shaft is rotatably supported in a rotating frame. The drive bevel gear meshes with the central bevel gear. The drive bevel gear is disposed radially inward of the drive shaft. The driven coupler is disposed radially outward of the drive shaft.

[0011] The claw unit may include a linear guide and a slider that has a claw base and is guided by the linear guide to reciprocate in the radial direction. The linear guide is, for example, a linear guide or a ball spline. The linear guide may be a combination of a guide shaft and a guide nut. The linear guide is disposed on the rotating frame. Effect of the Invention

[0012] According to the present invention, a chucking method and a rotary chuck device can be provided that can mount and chuck brittle materials or large rotating bodies with high elasticity on a rotating spindle of a lathe or the like. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a longitudinal sectional view of a rotary chuck device according to an embodiment of the present invention; [Diagram 2] Cross section of line II in Figure 1 [Diagram 3] View of arrow III in Figure 1 [Figure 4] Control device of the embodiment [Diagram 5] 1 is a flowchart showing a chucking method according to an embodiment. [Figure 6] 1 is a diagram showing rotational speed and torque versus time in a chucking operation according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The rotary chuck device 10 of this embodiment includes a frame 11, a rotary motor 21, a shaft bracket 13, a main shaft 17, a main bearing 18, a rotary frame 27, a sub-shaft 29, a central bevel gear 31, a jaw unit 50, a jaw feed motor 46, a driving coupler 47, and a driven coupler 49. The rotary chuck device 10 may include a driving pulley 23, a driven pulley 19, an endless belt 25, a bearing stand 35, a sub-bearing 30, a driving bearing 36, a driving shaft 39, a cover 65, a driving bevel gear 48, a motor guide 43 (see FIG. 2), a motor bracket 45 (see FIG. 2), a cylinder 44 (see FIG. 2), jaws 63, and a seal 67.

[0015] Here, Fig. 1 is a cross-sectional view taken along line II in Fig. 2. For convenience, the rightward direction in Fig. 1 is defined as +X direction, the upward direction in Fig. 1 is defined as +Z direction, and the upward direction in Fig. 2 is defined as +Y direction. The +Z direction is the vertical upward direction. 1 to 3, the rotating shaft 1 is arranged in the vertical direction, but the installation direction is not important. For example, the rotating shaft 1 may be arranged in the horizontal direction. For convenience, Fig. 1 shows the pawl feed motor 46 in the engaged position 5. Fig. 2 shows the pawl feed motor 46 in the disengaged position 6.

[0016] The frame 11 moves, for example, up and down along the Z direction. The rotary motor 21 is disposed on the frame 11. The rotary motor 21 is, for example, a servo motor or a stepping motor. The shaft bracket 13 is disposed on the frame 11 and has a hollow cylindrical shape.

[0017] The main shaft 17 is supported by the shaft bracket 13 via a main bearing 18. The main shaft 17 extends in the vertical direction (Z direction). The driving pulley 23 is connected to the rotary motor 21. The driven pulley 19 is connected to the main shaft 17. An endless belt 25 is stretched between the driving pulley 23 and the driven pulley 19.

[0018] As shown in FIG. 1 and FIG. 2, the rotating frame 27 has a base end plate 27a, a tip plate 27b, and a connecting column 27c. The rotating frame 27 is cage-shaped. The rotating frame 27 is fastened to the lower end of the main shaft 17. The base end plate 27a is circular and is arranged horizontally around the rotating shaft 1. The base end plate 27a may have a smaller diameter than the tip plate 27b. The base end plate 27a has a plurality of through holes 27e. The through holes 27e extend, for example, in the circumferential direction and open widely. The tip plate 27b is circular and is arranged around the rotating shaft 1. The tip plate 27b and the base end plate 27a are spaced apart. The tip plate 27b has a plurality of through holes 27f and a plurality of (three in FIG. 2) slide holes 27d. The through holes 27f extend in the circumferential direction and open widely. The slide holes 27d are arranged along the claw unit 50. The slide hole 27d extends in the radial direction. The connecting pillar 27c connects the base end plate 27a and the tip plate 27b. For example, the connecting pillar 27c is arranged rotationally symmetrically about the rotation axis 1.

[0019] The sub-shaft 29 is disposed at the tip of the main shaft 17 along the rotation axis 1. The sub-shaft 29 is supported between the main shaft 17 and the tip plate 27b via a sub-bearing 30. A central bevel gear 31 is fastened to the sub-shaft 29.

[0020] The bearing stand 35 is disposed on the tip plate 27b. The bearing stand 35 has a driving bearing 36. The driving shaft 39 extends in the X direction and is supported by the driving bearing 36. The driving shaft 39 has a driven coupler 49 and a driving bevel gear 48. The driving shaft 39 is disposed between the base end plate 27a and the tip plate 27b. The drive bevel gear 48 is disposed at a radially inner end of the drive shaft 39. The drive bevel gear 48 meshes with the central bevel gear 31. The driven coupler 49 is disposed on the radially outer end of the drive shaft 39. The driven coupler 49 may protrude from the outer periphery of the tip plate 27b. The driven coupler 49 has a plurality of protrusions 49a disposed on the radially outer end face of the drive shaft 39 (see FIG. 2).

[0021] The motor guide 43 extends in the X direction and is disposed on the frame 11. The motor guide 43 is a linear guide. The motor guide 43 is, for example, a straight line guide. The motor bracket 45 is disposed on the motor guide 43. The motor bracket 45 is guided by the motor guide 43 and reciprocates between the coupled position 5 and the separated position 6.

[0022] The cylinder 44 is disposed on the frame 11. The cylinder 44 reciprocates the motor bracket 45 in the radial direction (X direction in FIG. 1). The cylinder 44 advances and retreats the motor bracket 45 via an air source (not shown) and a directional control valve (not shown). The cylinder 44 is, for example, an air cylinder or an electric cylinder.

[0023] The pawl feed motor 46 is disposed on the motor bracket 45. The pawl feed motor 46 is, for example, a servo motor or a stepping motor. The pawl feed motor 46 may have an angle detection sensor. The angle detection sensor may be either an absolute type or an incremental type.

[0024] The driving coupler 47 is cylindrical. The driving coupler 47 is connected to the pawl feed motor 46. For example, the driving coupler 47 is directly connected to the output shaft of the pawl feed motor 46. The central axis of the driving coupler 47 passes through the rotating shaft 1. The driving coupler 47 has a plurality of protrusions 47a arranged on an end face radially inward with respect to the rotating shaft 1. The driving coupler 47 reciprocates in the X direction together with the pawl feed motor 46 and the motor bracket 45. The driving coupler 47 is connected to the driven coupler 49 at the coupling position 5. At this time, the protrusions 47a and the protrusions 49a mesh with each other. The coupling position 5 is, for example, the stroke end of the driving coupler 47 on the radial inner side with respect to the rotating shaft 1. The driving coupler 47 is separated from the driven coupler 49 at the separation position 6. When the driving coupler 47 is at the separation position 6, the rotating frame 27 can rotate freely.

[0025] The claw units 50 are arranged with n-fold symmetry (n=3 in FIG. 2) around the rotation axis 1. Hereinafter, the claw unit 50 arranged on the right side (+X side) in FIG. 1 will be described. As shown in Figures 1 and 2, the claw unit 50 has a feed screw 55, a driven bevel gear 57, a slide bracket 51, a ball spline (linear guide) 56, a driven bearing 52, a slider 59, a claw base 60, a contact portion 64, a claw hole 65a, and a seal 67.

[0026] The feed screw 55 has a screw shaft 55a and a feed nut 55b. The feed screw 55 is, for example, a triangular screw or a trapezoidal screw. The screw shaft 55a extends along a diameter. The driven bevel gear 57 is disposed at a radially inner end of the feed screw 55. The driven bevel gear 57 meshes with the central bevel gear 31. Both ends of the screw shaft 55a are supported by the slide bracket 51 via the driven bearing 52. The feed nut 55b is fastened to the slider 59.

[0027] A pair of slide brackets 51 are disposed in the radial direction of the rotation axis 1. Each slide bracket 51 extends vertically (XZ plane). The slide bracket 51 is disposed above the tip plate 27b and below the base end plate 27a. The pair of ball splines 56 extend parallel to the screw shaft 55a on both sides of the screw shaft 55a. The intervals between the pair of ball splines 56 and the screw shaft 55a are the same. The ball spline 56 has a slide shaft 56a and a slide nut 56b. Both ends of the slide shaft 56a are supported by the pair of slide brackets 51. The pair of slide shafts 56a are disposed at both ends of the slide bracket 51. The pair of slide nuts 56b are each fastened to a slider 59.

[0028] The slider 59 reciprocates in the radial direction (X direction) while being guided by the pair of ball splines 56. The slider 59 has a pillar portion 59a in the center. The pillar portion 59a protrudes downward and passes through the slide hole 27d.

[0029] The claw base 60 is connected to the lower part of the pillar portion 59a. The claw base 60 extends in the radial direction. The claw base 60 is disposed on a horizontal plane (XY plane). The claw base 60 is disposed below the tip plate 27b. The claw base 60 reciprocates in the radial direction together with the slider 59.

[0030] The claw 63 is attached to the claw base 60. The claw 63 may have an abutment portion 64. The claw 63 is cylindrical and extends in the direction of the rotation axis 1 (Z direction). The claw 63 is disposed below the claw base 60. The abutment portion 64 is disposed at the tip of the claw 63. The abutment portion 64 is an elastic body such as synthetic rubber. The abutment portion 64 abuts against the workpiece 3.

[0031] As shown in Figures 1 and 3, the cover 65 is a thin-walled stepped cylinder. The lower part of the cover 65 has a larger diameter than the upper part. The cover 65 covers the sub-shaft 29, the central bevel gear 31, the pawl unit 50, the driving shaft 39, and the driving bevel gear 48. The cover 65 has a pawl hole 65a. The pawl 63 passes through the pawl hole 65a. The driven coupler 49 passes through the side of the cover 65.

[0032] The seal 67 covers the gap between the nail hole 65a and the nail 63. The seal 67 is, for example, a pair of brushes 671. As shown in FIG. 3, the brush 671 has a bristle base 67a and bristles 67b. The bristle base 67a is disposed at both circumferential ends of the nail hole 65a. The bristle base 67a extends in the radial direction. The bristles 67b extend toward the center of the nail hole 65a. The bristles have a length approximately half the width of the nail hole 65a. The seal 67 prevents the inflow of cleaning fluid and cutting chips. The seal 67 may be a telescopic cover, such as a roll cover, a telescopic cover, or a bellows.

[0033] As shown in FIG. 4, the control device 71 has a sequence control means 73 , a storage means 81 , a pawl feed control means 75 , a rotary motor control means 89 , a cylinder control means 91 , and an input / output means 93 . The sequence control means 73 controls the pawl feed control means 75, the rotary motor control means 89, the cylinder control means 91, and the input / output means 93 in accordance with the processing sequence.

[0034] The storage means 81 stores a chuck diameter d0, a chuck offset amount d1, an upper limit speed n0, a fast-forward speed n1, an upper limit torque Tr0, a clamp completion threshold Tr1, a time threshold t0, and a rotation speed n2. Here, the chuck diameter d0 is the diameter of the jaws 63 when chucking the workpiece 3. The chuck offset amount d1 is the distance from the fast-forward end point of the jaws 63 when chucking the workpiece 3 to the chuck diameter d0. The chuck offset amount d1 is slightly larger than the sum of the variation in the diameter of the workpiece 3, the difference in distance between the rotation axis 1 and each jaw 63, and the eccentricity of the workpiece 3 from the rotation axis 1. The upper limit speed n0 is the upper limit of the rotation speed n of the jaw feed motor 46 when chucking the workpiece 3. The fast-forward speed n1 is the fast-forward speed of the jaw feed motor 46.

[0035] The upper limit torque Tr0 is the upper limit of the torque Tr of the jaw feed motor 46 when chucking the workpiece 3. Here, the upper limit torque Tr0 is a value that is not easily reached when the jaw feed motor 46 feeds the jaws 63 due to the feed resistance of the jaws 63. The clamping completion threshold Tr1 is the threshold of the torque Tr when clamping is completed. The clamping completion threshold Tr1 is set slightly smaller than the upper limit torque Tr0. For example, the clamping completion threshold Tr1 is a value that is 90 to 95% of the upper limit torque Tr0. The time threshold value t0 is a threshold value for the time when the torque Tr becomes equal to or greater than the clamp completion threshold value Tr1. For example, the time threshold value t0 is 0.2 to 0.6 s. The rotation speed n2 is the rotation speed of the rotary motor 21.

[0036] The chuck diameter d0, the chuck offset amount d1, the upper limit speed n0, the fast forward speed n1, the upper limit torque Tr0, the clamp completion threshold Tr1, the time threshold t0, and the rotational speed n2 are input or transferred to the memory means 81 via the input / output means 93. Here, the upper limit speed n0, the fast-forward speed n1, and the upper limit torque Tr0 may be omitted.

[0037] When the angle detection sensor of the jaw feed motor 46 is of the incremental type, the chuck diameter d0 and the chuck offset amount d1 may be omitted. In this case, a limit switch (not shown) may be disposed on the rotating frame 27 to detect the position of the slider 59 at the fast-forward stop position of the jaws 63 during chucking. There may be cases where multiple workpieces 3 are mixed. If the angle detection sensor of the jaw feed motor 46 is of the incremental type and multiple workpieces 3 are mixed, multiple limit switches (not shown) may be provided. The limit switch is disposed on the rotating frame 27 and detects the jaw base 60 or slider 59 at the position where fast forward ends. In this case, one limit switch may be provided that corresponds to the largest mixed workpiece.

[0038] The pawl feed control means 75 has a power supply control means 76 , a speed control means 77 , a torque monitoring means 78 , and a timer 79 . The power control means 76 excites and demagnetizes the pawl feed motor 46.

[0039] When chucking, the speed control means 77 feeds the pawl feed motor 46 quickly until the distance d from the rotating shaft 1 to the pawl 63 reaches d0 + d1 (when d0 + d1 < d). That is, the speed control means 77 sets the rotational speed n of the pawl feed motor 46 to the fast feed speed n1. When chucking, when the distance d of the pawl 63 from the rotating shaft 1 becomes d0 + d1 or less (when d < d0 + d1), the speed control means 77 keeps the rotational speed n of the pawl feed motor 46 at or below the upper limit speed n0. The speed control means 77 may keep the torque Tr of the pawl feed motor 46 at or below the upper limit torque Tr0 at this time. When unchucking, the speed control means 77 feeds the pawl feed motor 46 quickly. That is, the speed control means 77 sets the rotational speed n of the pawl feed motor 46 to the fast feed speed n1. When receiving a stop signal, the speed control means 77 stops the pawl feed motor 46.

[0040] The torque monitoring means 78 monitors the torque Tr of the pawl feed motor 46. The timer 79, in conjunction with the torque monitoring means 78, measures the time t during which the torque Tr becomes equal to or greater than the clamp completion threshold value Tr1. For example, when the time t exceeds the time threshold value t0, the timer 79 issues a stop signal. The speed control means 77 receives the stop signal from the timer 79. When the time t exceeds the time threshold value t0, the speed control means 77 stops the pawl feed motor 46.

[0041] The rotation motor control means 89 rotates and stops the rotation motor 21. The rotation motor control means 89 stops the rotation frame 27 at a predetermined original position 9. Here, when the rotation frame 27 is at the original position 9, the rotation phases of the driven coupler 49 and the driving coupler 47 coincide. The cylinder control means 91 advances and retracts the cylinder 44.

[0042] The input / output means 93 has an I / O port and an input / output device. The input / output means 93 communicates control signals with the pawl feed motor 46, the rotary motor 21, an air source (not shown), and a directional control valve (not shown). The input / output means 93 also stores each piece of data in the memory means 81 and erases it.

[0043] The chucking and unchucking method of this embodiment will be described with reference to Fig. 5. Here, steps S1 to S9 indicate the chucking process. Step S10 indicates control in the machining process. Steps S11 to S15 indicate the unchucking process. First, the jaw feed motor 46 is demagnetized (step S1). Next, the driving coupler 47 and the driven coupler 49 are coupled (step S2). Next, the jaw feed motor 46 is excited (step S3). Next, the jaws are fed (steps S5 to S8). Next, the driving coupler 47 and the driven coupler 49 are separated (step S9). Next, the rotating frame 27 is rotated to perform processing. Then, the rotation of the rotating frame 27 is stopped (step S10). After processing, the jaw feed motor 46 is demagnetized (step S11). Next, the driving coupler 47 and the driven coupler 49 are coupled (step S12). Next, the jaw feed motor 46 is excited (step S13). Next, the jaws are fed (step S14). Finally, the driving coupler 47 and the driven coupler 49 are separated (step S15).

[0044] Here, step S1 and step S11 are the same, step S2 and step S12 are the same, step S3 and step S13 are the same, and step S9 and step S15 are the same. Each step will now be described in detail.

[0045] In step S1, the power supply control means 76 demagnetizes the pawl feed motor 46. Then, the driving coupler 47 becomes freely rotatable about the central axis (X-axis) of the driving coupler 47. In step S2, the cylinder control means 91 extends the cylinder 44 and moves the driving coupler 47 to the coupling position 5. Then, the driving coupler 47 and the driven coupler 49 are connected. At this time, since the driving coupler 47 is rotatable, even if the driving coupler 47 and the driven coupler 49 are slightly out of phase with each other, the driving coupler 47 follows the driven coupler 49 and is smoothly inserted.

[0046] In step S3, the power supply control means 76 excites the pawl feed motor 46. In step S4, the speed control means 77 feeds the jaws 63 radially inward until the distance d becomes d0+d1. Here, the speed control means 77 fast-forwards the jaws 63. The jaw feed motor 46 rotates at a fast-forward speed n1. Step S4 is performed during a period t=t2 to t3 in FIG. 6. Here, in FIG. 6, the dashed line indicates the change in the rotation speed n of the jaw feed motor 46 over time. In FIG. 6, the right vertical axis indicates the rotation speed n of the jaw feed motor 46, the left vertical axis indicates the torque Tr of the jaw feed motor 46, and the horizontal axis indicates time. At the end of step S4, the workpiece 3 and the jaws 63 are separated.

[0047] Next, the claw feeding in the state where the claws 63 are in contact with the workpiece 3 (steps S5 to S8) will be described. In step S5, the speed control means 77 drives the pawl 63 so that the rotation speed n of the pawl feed motor 46 is kept equal to or lower than the upper limit speed n0. Preferably, the speed control means 77 drives the pawl 63 so that the torque Tr of the pawl feed motor 46 does not exceed the upper limit torque Tr0. In step S6, the torque monitoring means 78 monitors the torque Tr of the pawl feed motor 46. Step S6 is started simultaneously with step S5. Step S6 is performed during the period t=t3 to t4 in FIG. 6.

[0048] As shown in Fig. 6, the jaw feed motor 46 rotates at the upper limit speed n0 until the jaw 63 contacts the workpiece 3. At this time, the torque Tr maintains a low value equivalent to the sum of the rotational resistance of the feed screw 55 and the resistance of the slider 59. When the jaw 63 contacts the workpiece 3, the torque Tr increases rapidly. Then, the rotation speed n of the jaw feed motor 46 decreases toward 0. When the torque Tr becomes equal to or greater than the clamp completion threshold value Tr1 (Yes in step S6), the process proceeds to step S7. Otherwise, the speed control means 77 continues to rotate the jaw feed motor 46 (step S5). In step S7, the timer 79 measures the time t at which the torque Tr becomes equal to or greater than the clamp completion threshold Tr1. When the time t exceeds the time threshold t0 (Yes in step S7), the process proceeds to step S8. In other cases, the speed control means 77 continues to rotate the jaw feed motor 46 (step S5). In step S8, the speed control means 77 stops the jaw feed motor 46. At this time, the rotation speed n becomes substantially 0. Furthermore, the torque Tr also becomes substantially 0.

[0049] In step S9, the cylinder control means 91 retracts the cylinder 44. The pawl feed motor 46 and the driving coupler 47 move to the separated position 6. The driving coupler 47 separates from the driven coupler 49. The rotating frame 27 becomes rotatable. At this time, the screw shaft 55a does not rotate due to resistance with the feed nut 55b.

[0050] In step S10, the rotary motor control means 89 rotates the rotary motor 21. Here, the workpiece 3 is machined and cleaned. Thereafter, the rotary motor control means 89 stops the rotary motor 21. At this time, the rotating frame 27 stops at the original position 9.

[0051] In step S14, the speed control means 77 rotates the pawl feed motor 46 to move the pawls 63 radially outward. Here, the speed control means 77 may feed the pawls 63 at a fast rate.

[0052] According to the rotary chuck device 10 of this embodiment, the jaws 63 have the contact portions 64 which are elastic bodies. Therefore, in step S5, when the jaws 63 come into contact with the workpiece 3, the torque Tr increases linearly with respect to the time t. Then, when the time t at which the torque Tr is equal to or greater than the clamp completion threshold value Tr1 exceeds the time threshold value t0, the rotary chuck device 10 completes the chucking.

[0053] The jaws 63 move symmetrically about the rotation axis 1. Furthermore, the jaws 63 approach the workpiece 3 at a speed corresponding to the upper limit speed n0. If the upper limit speed n0 and the upper limit torque Tr0 are set relatively low, the rotary chuck device 10 can chuck the workpiece 3 gently. Then, the workpiece 3 is automatically centered. The rotary chuck device 10 moves the jaw base 60 via a feed screw 55. Therefore, the chuck diameter can be set large. Due to the above-mentioned operational effects, the rotary chuck device 10 has elasticity and can chuck the large-diameter workpiece 3 at the center position while suppressing distortion. The rotary chuck device 10 is also suitable for centering the large-diameter workpiece 3 made of a brittle body.

[0054] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention, and all technical matters included in the technical ideas described in the claims are the subject of the present invention. The above-described embodiment shows a preferred example, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the attached claims. [Explanation of symbols]

[0055] 3 Work 10 Rotating chuck device 45 Drive Coupler 46 Jaw feed motor 49 Driven Coupler 63 Nails

Claims

1. Demagnetize the pawl feed motor, Inserting the driving coupler, which is in a freely rotatable state, into the driven coupler to connect the driving coupler and the driven coupler; Exciting the pawl feed motor; Rotating the jaw feed motor to move the jaws in an interlocking manner via the driving coupler and the driven coupler to chuck and unchuck the workpiece; Pulling the driving coupler out from the driven coupler to separate the driving coupler and the driven coupler; Chuck method.

2. When chucking the workpiece, the jaw feed motor is rotated so that the rotation speed of the jaw feed motor is equal to or lower than an upper limit speed, and the jaws are fed until the torque of the jaw feed motor becomes equal to or higher than a clamp completion threshold value.

2. The chucking method according to claim 1.

3. When chucking the workpiece, the jaw feed motor is rotated so that the torque of the jaw feed motor is equal to or lower than an upper limit torque. The chucking method according to claim 2 .

4. When the time during which the torque is equal to or greater than the clamp completion threshold reaches a predefined time threshold, the jaw feed motor is stopped to complete the chucking. The chucking method according to claim 2 or 3.

5. demagnetizing the pawl feed motor immediately before inserting the driving coupler into the driven coupler; The chucking method according to any one of claims 1 to 3.

6. The pawl feed motor is excited except when the driving coupler is inserted into the driven coupler. The chucking method according to any one of claims 1 to 3.

7. A rotating frame supported so as to be rotatable about a rotation axis; a central bevel gear supported within the rotating frame so as to be rotatable about the rotation axis; a driven coupler connected to the central bevel gear; a driving coupler that moves forward and backward in a radial direction of the rotating frame, the driving coupler connecting with the driven coupler when moving forward in the direction of the rotation axis and disconnecting from the driven coupler when moving backward from the rotation axis; a pawl feed motor connected to the driving coupler; A plurality of claw units arranged on the rotating frame rotationally symmetrically about the rotation axis, each of the claw units comprising: a slider having a claw base and reciprocating in a radial direction of the rotating frame; a feed screw having a driven bevel gear meshing with the central bevel gear, extending along a radial direction of the rotating frame, and feeding the slider; having A control device, a storage device that stores an upper limit speed that is an upper limit of the rotation speed of the pawl feed motor and a clamp completion threshold value that is smaller than an upper limit of the torque of the pawl feed motor; a power supply control means for demagnetizing the pawl feed motor when the driving coupler is advanced to connect with the driven coupler; a jaw feed control means for controlling the jaw feed motor so that the rotation speed of the jaw feed motor is kept below the upper limit speed when the jaw base is fed during chucking, and the jaw feed motor is stopped when the torque of the jaw feed motor becomes equal to or greater than the clamp completion threshold value; A control device having A rotary chuck device having a

8. the storage device stores an upper limit torque that is an upper limit of the torque of the pawl feed motor; the jaw feed control means maintains the torque of the jaw feed motor at or below the upper limit torque when feeding the jaw base during chucking; The rotary chuck device according to claim 7.

9. the storage device stores a time threshold value that is a threshold value of the time for which the torque of the pawl feed motor is equal to or greater than the upper limit torque; the jaw feed control means further includes a timer for stopping the jaw feed motor when a time during which the torque of the jaw feed motor becomes equal to or greater than the clamp completion threshold exceeds the time threshold during chucking. The rotary chuck device according to claim 7 or 8.

10. The power supply control means excites the pawl feed motor except when the driving coupler is advanced to connect with the driven coupler. The rotary chuck device according to claim 7 or 8.

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