JP6600194B2 - Chuck device - Google Patents

Description

  The present invention relates to a chuck device including a clamp detection structure that detects the presence or absence of a clamp.

  A chuck device such as a machine tool includes a clamp detection structure for detecting a clamp state of a workpiece. Patent Document 1 below discloses a chuck device having a clamp detection structure. In the chuck device, a rod-like draw bar is inserted into a rotatable main shaft so as to be movable in the axial direction, and the draw bar is urged rearward by a spring. Thus, the tool holder is clamped by pulling the collet chuck provided at the tip.

  On the other hand, a hydraulic cylinder is provided at the rear part of the chuck device, and the collet chuck is released and the tool holder is unclamped by moving the draw bar forward by the hydraulic cylinder. Therefore, the chuck device is configured such that clamping and unclamping are performed by the front chuck mechanism when the hydraulic cylinder located at the rear of the main shaft operates the draw bar. The hydraulic cylinder that executes such driving is provided with a proximity switch for detecting displacement with respect to the piston, and the clamping state by the collet chuck is discriminated based on the detection signal of the proximity switch to control the rotation with respect to the main shaft. It has come to be.

JP 2004-025389 A JP 2005-212084 A

  In the chuck device of the first conventional example, a draw bar is inserted at the center of rotation of the main shaft, and the collet chuck is clamped and unclamped by a hydraulic cylinder provided at the rear of the main shaft. Therefore, in the case of the conventional chuck device, the central portion of the main shaft where the draw bar is located cannot be used even if there is a need to incorporate a structure for performing other functions. In this regard, Patent Document 2 discloses a chuck device having a configuration in which a hydraulic cylinder is brought close to a collet chuck and a draw bar is omitted. Specifically, a taper cone is disposed in the direction of the orthogonal rotation axis with respect to a rod that grips a workpiece that is movable in the radial direction, and the taper cone, the shaft, and the piston of the hydraulic cylinder are integrally configured. Then, the hydraulic oil is supplied to and discharged from the hydraulic cylinder, whereby the workpiece is gripped and released by the rod.

  Therefore, the chuck device of the second conventional example has a configuration in which the distance between the chuck mechanism and the hydraulic cylinder is extremely short, and the hydraulic cylinder is arranged in front of the main shaft. Therefore, the rear side of the hydraulic cylinder for driving the collet chuck can be freely designed even if it is the central portion of the main shaft. However, the chuck device of the second conventional example has a configuration in which a hydraulic cylinder is incorporated in the main body of the device, and a proximity sensor for detecting the displacement of the piston is installed as in the first conventional example. It is impossible to detect the presence or absence of the clamp.

  Accordingly, an object of the present invention is to provide a chuck device having a clamp detection structure in order to solve such a problem.

The chuck device according to the present invention includes a hydraulic cylinder inside the apparatus main body, and operates clamping means connected to the piston to switch between clamping and unclamping of the workpiece. Is formed with a clamp detection flow path through which detection air is sent, and an opening of the clamp detection flow path and an air discharge hole communicating with the outside are provided in a space formed inside the apparatus main body. The lid member that opens and closes the opening is formed so as to be interlocked with the piston, and an overclamp detection flow path into which detection air is sent is formed in the device main body. An over-detecting member capable of switching between the flow of detection air flowing from the over-clamp detection flow path to the air discharge hole and blocking is provided. The switching of the over-detection member associated with the displacement of the piston during Overclamp, detecting air flow of the Overclamp detecting passage is that so as to cut off.

  According to the present invention, the workpiece is clamped and unclamped by driving the hydraulic cylinder inside the apparatus body. At this time, the lid member opens and closes the opening in conjunction with the displacement of the piston of the hydraulic cylinder. I will let you. At this time, since the flow of the detection air flowing through the clamp detection flow channel and the cutoff thereof are switched, it is possible to discriminate between clamp and unclamp by detecting the state.

It is the perspective view which showed the processing module which is the principal part of a machine tool. It is the figure which simplified and showed the spindle head, the chuck device, and the tool magazine. It is sectional drawing which showed the chuck device of embodiment. FIG. 4 is a cross-sectional view showing the same chuck device as FIG. 3. It is an expanded sectional view showing a part of chuck device at the time of clamping. It is an expanded sectional view showing a part of chuck device at the time of over clamp.

  Next, an embodiment of a chuck device according to the present invention will be described below with reference to the drawings. In the present embodiment, a chuck device incorporated in a machine tool will be described as an example. FIG. 1 is a perspective view showing a machining module, which is a machine tool of the present embodiment, and particularly a main part. This machine tool is a machining center, and is a machine tool line in which a plurality of machine tools are installed in the width direction. The machine tool line is particularly compact with a reduced size in the width direction, and each machine tool itself is designed to be compact so that two machine tools are mounted on one base 3 shown in the figure. ing.

  In the illustrated machining center, a machining chamber is configured by covering the machining module 1 with a machine body cover (not shown). The processing module 1 is mounted on the base 3 so as to be movable in the front-rear direction, and is assembled on a movable bed 5 having wheels. In the present embodiment, the machine body longitudinal direction of the machining center 1 (processing module 1) is the Y-axis direction, the machine body width direction is the X-axis direction, and the machine body vertical direction is the Z-axis direction.

  In the machining module 1, a spindle head 11 that holds a machining tool is provided at the front of the machine body. The spindle head 11 has a spindle chuck 12 to which a tool such as a drill, reamer, and boring can be attached and detached, and a spindle motor 13 that rotates a tool held by the spindle chuck 12. A chuck device 15 that grips a workpiece rotatably is disposed below the spindle head 11, while the rotation axis of the spindle head 11 is in the vertical Z-axis direction, whereas the rotation axis of the chuck device 15 is horizontal. In the Y-axis direction, and both rotation axes are orthogonal to each other.

  The chuck device 15 is a collet chuck that is attached to the mount 16 on the movable bed 5 so as to protrude toward the front side of the machine body, and the workpiece is delivered to and from a transfer device (not shown). Yes. Then, a predetermined process is performed on the work gripped by the chuck device 15 with the tool of the spindle head 11. The machining drive device for that purpose includes a Z-axis drive mechanism for moving the tool held by the spindle head 11 in the Z-axis direction, an X-axis drive mechanism for moving in the X-axis direction, and a movement in the Y-axis direction. Y-axis drive mechanism is provided.

  The machining module 1 is designed such that the drive mechanisms in the three axial directions are arranged in the longitudinal direction of the machine body and the width dimension of the machine body is reduced. Specifically, the Y-axis drive mechanism is mounted such that the Y-axis slider 21 is movable in the Y-axis direction on the magazine main body 24 integral with the movable bed 5, and the X-axis drive mechanism is X-axis relative to the Y-axis slider 21. A slider 22 is mounted so as to be movable in the X-axis direction. Further, in the Z-axis drive mechanism, a Z-axis slider 23 is mounted so as to be movable in the Z-axis direction with respect to the X-axis slider, and the spindle head 11 is mounted on the Z-axis slider 23.

Each of the Y-axis slider 21, the X-axis slider 22, and the Z-axis slider 23 is slidably fitted with a guide rail and a guide block, and is slidably mounted in each direction. In each drive mechanism, a nut fixed to each slider is screwed onto a screw shaft connected to the rotation shaft of the servo motor. Thus, by the drive control of the servo motors, the outputted rotation is converted into linear motion, Y-axis slider 21, X-axis slider 22 and the Z-axis slider 23 is to move a predetermined amount in each direction. As a result, the position of the tool held by the spindle head 11 with respect to the work gripped by the chuck device 15 is controlled.

  The processing module 1 stores a tool magazine holding a plurality of tools in a magazine box 24 located between the chuck device 15 and the spindle head 11. Here, FIG. 2 is a diagram showing the spindle head 11, the chuck device 15, and the tool magazine 18 in a simplified manner. The tool magazine 18 includes a plurality of tools T and includes a feed mechanism for moving the target tool T to a front replacement position. The tool magazine 18 is configured to jump forward as shown in the figure in conjunction with opening of the opening / closing door of the magazine box 24 when changing the tool with respect to the spindle head 11.

  Such tool change and machining of workpieces are controlled according to a program for the spindle motor 13 and the drive motor of the chuck device 15 as well as the machining drive device of the spindle head 11 and each drive part of the tool magazine 18. Done. In this regard, the processing module 1 is equipped with a control panel 19 behind the movable bed 5 as shown in FIG.

  By the way, the machining center (processing module 1) of the present embodiment has an arrangement in which a Y-axis slider 21, an X-axis slider 22, and a Z-axis slider 23 are arranged in front of the control panel 19 and overlapped in the Y-axis direction. As described above, the width dimension is designed to be compact. For this reason, since the movement range of the spindle head 11 is also limited, the tool detection device for detecting breakage of the tool has a compact configuration.

  In the tool detection device of this embodiment, a touch sensor 25 is attached to the circumferential surface of the chuck device 15. Therefore, as shown by an arrow in FIG. 2, when the tool T is gripped by the spindle chuck 12, the tip of the tool T is applied to the touch sensor 25 by moving the tool T up and down at the tool change position, and the blade Breakage detection such as spillage and automatic tool length correction are performed. The touch sensor 25 is formed with a b contact circuit so as to transmit an OFF signal when the tool T is touched, for example, but is connected to the movable coil 27 and has a center position with respect to the movable coil 27. The combined fixed coil 28 is installed in close proximity. The fixed coil 28 is connected to a power source and is connected to the control device 19 via an amplifier.

  As described above, in the present embodiment, electric power is conveyed by the magnetic induction action of the movable coil 27 and the fixed coil 28 so that the electric power and the detection signal can be wirelessly transmitted to the touch sensor 25 rotated by the chuck device 15. A contactless power transfer system is used. In the contactless power transfer system, the movable coil 27 and the fixed coil 28 need to be arranged coaxially, so that the movable coil 27 is installed at the rear end portion of the main shaft 31, particularly the rotation center portion. Space must be secured.

  Therefore, the chuck device 15 mounted on the machining module 1 has a structure in which a hydraulic cylinder is incorporated in the apparatus main body, as in the case of Patent Document 2. As shown in FIG. 2, the chuck device 15 is fixed to a front end portion of a main shaft 31 that is rotatably attached to the gantry 16. The main shaft 31 is provided with a reduction gear 33 in which large and small gears are engaged, and the rotation output of the servo motor 32 is transmitted to the main shaft 31 via the reduction gear 33.

  FIG. 3 is a cross-sectional view showing the chuck device 15. In the chuck device 15, a base block 41 is fixed to a rotating main shaft 31 via a main shaft face plate 36. Further, a ring member 42 and a receiving member 43 are overlapped and fixed integrally with the base block 41 on the front side of the rotating shaft, and an apparatus main body of the chuck device 15 is formed. Note that the right side of the chuck device 15 is the front of the processing module 1 and the left side of the drawing is the rear.

  The cylinder-shaped base block 41 has a cylinder member 45 inserted into its internal space to form a hydraulic cylinder. The cylinder member 45 is integrated with the ring member 42, and a piston 46 is inserted into a cylinder space formed by both. A pressurizing chamber in which hydraulic oil is supplied and discharged is formed in the cylinder space provided on the front and rear sides of the piston 46.

  As shown in FIG. 2, the main shaft 31 to which the chuck device 15 is fixed is assembled with a rotary valve 35 at the rear end portion so that hydraulic oil and detection air are fed into the rotating main shaft 31. The main shaft 31 that is a hollow rod is formed with a plurality of passages that penetrate in the axial direction in the circumferential direction, and hydraulic oil, detection air, and the like are fed through the rotary valve 35. The flow path of the main shaft 31 is connected to the flow path formed in the chuck device 15, and hydraulic oil for operating the hydraulic cylinder, detection air for detecting a clamp, and the like are sent to the chuck device 15. It is like that. FIG. 3 shows a clamp channel 47 and an unclamp channel 48 for feeding hydraulic oil to the pressurizing chamber of the piston 46 among the plurality of channels.

  The hydraulic oil flowing through the clamp channel 47 is supplied into the pressurizing chamber from the opening of the ring member 42 and acts so as to pressurize the piston 46 to the rear side. It is supplied into the pressurizing chamber from the opening of the cylinder member 45 and acts to pressurize the piston 46 forward. In this way, the piston 46 that is displaced in the front-rear direction has the mandrel 51 integrally assembled via a screw portion. A mandrel 51 that reciprocates in the axial direction integrally with the piston 46 is fitted into a cylindrical bushing 52 and attached in a state that allows sliding with a stable central axis position.

  The bushing 52 is fitted into a collet member 53 fixed to the ring member 42 and is screwed to the flange portion 53a. In addition to the flange portion 53a, the collet member 53 includes a cylindrical portion 53b in which a plurality of slits parallel to the central axis are formed, and a clamp portion 53c that protrudes toward the inner diameter side at the distal end portion of the cylindrical portion 53b. Yes. A tapered portion 51a that is inclined so that its diameter increases toward the front is formed at the tip of the mandrel 51, and is disposed to face the tapered surface of the clamp portion 53c.

  A workpiece W having a hollow portion indicated by a one-dot chain line is attached to the tip of the chuck device 15. The workpiece W is pressed against the seating surface 43a formed on the receiving member 43, and in this state, the clamp portion 53c of the collet member 53 is pressed radially outward and is gripped from the inside. At this time, the chuck device 15 is supplied with hydraulic oil to the clamp channel 47 side, the piston 46 is pressurized rearward (left side in the drawing), and the mandrel 51 moves together. In the collet member 53, the cylindrical portion 53b is bent, and the clamp portion 53c is pushed outward by the tapered portion 51a of the mandrel 51.

On the other hand, when the hydraulic fluid is supplied to the unclamp flow path 48 side, the chuck device 15 pressurizes the piston 46 forward (right side in the drawing), and the mandrel 51 moves together in the same direction. In the collet member 53, the clamp portion 53c returns to the inside following the movement of the tapered portion 51a, and the restriction on the workpiece W is released. By displacing the piston 46 in this manner, the workpiece W is clamped and unclamped. In the machining center (processing module 1), when the chuck device 15 confirms the clamping state of the workpiece W, the spindle 31 is rotated, and the workpiece W is cut . Therefore, the chuck device 15 is provided with a clamp detection structure for detecting the clamp state of the workpiece W.

Regarding the clamp confirmation, in Patent Document 1, since the hydraulic cylinder is provided at the rear portion of the main shaft, the displacement of the piston can be directly detected. However, the chuck device 15 cannot detect the displacement of the piston 46 directly because the hydraulic cylinder is incorporated in the main body of the device such as the base block 41 as in the case of Patent Document 2. Therefore, in the present embodiment, the following clamp detection structure is configured in order to accurately grasp the clamp state. FIG. 4 is a cross-sectional view showing the same chuck device 15 as FIG. However, the cross section of the air flow path different from FIG. 3 is shown.

  A cover member 55 is fixed to the cylinder member 45 from the rear side, and a space 56 is formed between them. On the other hand, the piston 46 and the mandrel 51 are formed with a through-hole passing through the central portion, and a detection rod 57 is inserted therein. The detection rod 57 is formed with a male threaded portion, and is screwed into and integrated with the piston 46 formed with the female threaded portion. The detection rod 57 is formed with a hexagonal hole 57a at the tip, and the position of the detection rod 57 in the axial direction with respect to the piston 46 can be adjusted by rotation using a hexagonal bar spanner. Further, the other end of the detection rod 57 extends to the inside of the space 56, and a hooking board 60 is fixed to the end thereof.

  A ring plate 58 is disposed inside the space 56 on the cylinder member 45 side and is biased by a spring 59 so as to come into contact with the end surface of the cover member 55. The ring plate 58 is for closing the opening of the clamp detection channel 61 formed on the end surface of the cover member 55. On the other hand, the catching plate 60 of the detection rod 57 is positioned on the cover member 55 side in the space 56, and the catching plate 60 resists the urging force of the spring 59 by driving the piston 46. The cover member 55 is configured to be separated from the end surface, that is, to open the opening of the clamp detection channel 61.

  As described above, in the chuck device 15, when the piston is unclamped, the piston 46 is pressurized forward (right side in the drawing), and the detection rod 57 and the hooking plate 60 move together in the same direction. At this time, the hooking plate 60 separates the ring plate 58 from the end surface of the cover member 55 against the urging force of the spring 59. Conversely, when clamping, the piston 46 is pressurized rearward (left side of the drawing), and the detection rod 57 and the hooking plate 60 move together in the same direction, so that the ring plate 58 is released from the hooking plate 60. Is done. Therefore, the ring plate 58 is pressed against the end surface of the cover member 55 by the urging force of the spring 59. Due to the displacement of the ring plate 58, the open / close state of the opening of the clamp detection channel 61 is switched.

  Further, the chuck device 15 has a structure in which an over-clamp state can be detected so that it can be confirmed that the mandrel 51 has been pulled too much. Here, FIGS. 5 and 6 are enlarged cross-sectional views showing a part of the chuck device 15 shown in FIG. A space 63 closed by a plate 64 is formed in the cylindrical cover member 55, and a detection piece 62 is slidably inserted into a penetrating portion connecting the space 63 and the space 56. The cylindrical detection piece 62 is urged toward the detection rod 57 by a spring 65 loaded in the space 63, and the flange portion is hooked and positioned as shown. Further, the detection piece 62 is formed with a through-hole 62a that allows the space 63 to communicate with the space 56, and is blocked by the tip of the detection rod 57 being applied to the detection piece 62 as shown in FIG. It has become.

  The chuck device 15 clamps the workpiece W when the piston 46 is pressed rearward (left side of the drawing) (the state shown in FIG. 5), but when the piston 46 is further pressed and displaced. Is overclamped (state shown in FIG. 6). At this time, the tip of the detection rod 57 is pressed against the detection piece 62 and the through hole 62a is blocked, so that the over clamp state can be detected. An overclamp detection flow channel 66 is formed in the chuck device 15, and an opening thereof is provided in the space 63.

  Incidentally, an air discharge hole 55a is formed in the cover member 55 so that the detection air in the space 56 is discharged to the outside. Therefore, the detection air supplied to the clamp detection flow path 61 is discharged to the outside through the air discharge hole 55a when the opening is opened by the separation of the ring plate 58. Further, the detection air supplied to the overclamp detection flow channel 66 is also connected to the space 63 and the space 56 through the through hole 62a of the detection piece 62, and is thus released to the outside through the air discharge hole 55a. It has come to be.

  In the clamp detection of the chuck device 15, detection air (compressed air) supplied from an air supply source (not shown) is constantly sent to the clamp detection channel 61 and the overclamp detection channel 66. . In each of the detection flow paths 61 and 62, the pressure in the flow path that changes depending on whether the flow of detection air is allowed and the blocked state where the flow is stopped is detected by a pressure switch (not shown).

  In the chuck device 15, the piston 46 is normally located at the position shown in FIG. 4, and the detection air sent to the clamp detection flow path 61 is discharged from the opening of the space 56 to the outside through the air discharge hole 55 a. Is done. Therefore, since the pressure in the clamp detection flow path 61 is lower than the set value, it is detected by the pressure switch (not shown) that the chuck device 15 is in the unclamped state. On the other hand, when the piston 46 is displaced to the position shown in FIGS. 3 and 5, the ring plate 58 released from the hooking plate 60 closes the opening, so that the detection air in the clamp detection flow path 61 The flow is stopped and the pressure inside the flow path increases. At this time, since the pressure in the flow path exceeds the set value, a signal is transmitted from the pressure switch to detect that the chuck device 15 is in the clamped state.

  When the workpiece W is clamped, the detection rod 57 is usually separated from the detection piece 62 as shown in FIG. Therefore, the detection air sent into the overclamp detection flow channel 66 passes through the through hole 62a of the detection piece 62 from the opening of the space 63 and is discharged to the outside through the air discharge hole 55a of the space 56. . Therefore, since the pressure in the overclamp detection flow channel 66 is lower than the set value, it is detected by the pressure switch (not shown) that the chuck device 15 is normally clamped. On the other hand, when the detection rod 57 is pressed against the detection piece 62 and the through hole 62a is blocked, the flow of detection air in the overclamp detection flow path 62 is stopped and the pressure inside the flow path increases. Thereby, since the pressure in the flow path exceeds the set value, a signal is transmitted from the pressure switch, and it is detected that the chuck device 15 is in the over clamp state.

  Although not shown, an opening for a seating detection flow path is also formed on the seating surface 43a of the receiving member 43 against which the workpiece W is pressed, and detection air (compressed air) is also formed in the seating detection flow path. Is always sent. Therefore, when the workpiece W is correctly applied to the seating surface 43a, the pressure in the seating detection flow path increases due to the opening being blocked. Sitting is detected. On the other hand, if the workpiece W is improperly seated, the detection air leaks and the pressure in the seating detection flow path does not increase and is lower than the set value. Is detected.

  In the machining center according to this embodiment, the touch sensor 25 is fixed to the circumferential surface of the chuck device 15 and the tool is detected there. Therefore, there is no special structure or space for attaching the tool detection member inside the processing chamber, and it is possible to reduce the size of the machine body when designing the machine tool. In addition, in order to make the touch sensor 25 small, a wired structure is used. However, in order to transfer power to the touch sensor 25 installed in the chuck device 15 that is a rotating body, the end surface of the main shaft 31 is used. It becomes necessary to arrange a coupling composed of the movable coil 27 and the fixed coil 28.

  In this embodiment, a hydraulic cylinder is provided inside the chuck device 15, but a clamp detection structure for detecting a clamp state associated with the displacement of the piston 46 is provided. Therefore, it is possible to secure a space at the rear end portion of the main shaft 31, particularly the rotation center portion, and to attach the movable coil 27 capable of power transfer with the fixed coil 28. Further, it is possible to detect the state of clamping and unclamping by the chuck device 15 incorporating a hydraulic cylinder. Therefore, according to the present embodiment, even the chuck device 15 having a built-in hydraulic cylinder can appropriately detect the clamped state and the unclamped state, and safe machining control of a machine tool such as a machining center is performed.

  In particular, as the clamp detection structure, the pressure by the detection air sent into the flow path is detected, so that the structure inside the chuck device 15 is not complicated. That is, the above effect is realized by a simple structure in which the ring plate 58 as a lid member is urged by the spring 59 and the ring plate 58 is operated by the detection rod 57 and the hooking plate 60 integrated with the piston 46 and the mandrel 51. can do. Furthermore, in this embodiment, the overclamp state can be detected by checking the pressure of the detection air sent into the overclamp detection flow channel 66 by the configuration of the detection piece 62 and the like. In this respect as well, safe machining control of machine tools such as machining centers is performed.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
For example, in the above-described embodiment, the clamp detection structure for switching the flow of detection air supplied to the clamp detection flow path 61 and the over clamp detection flow path 66 is provided. The structure to be blocked may be one that uses a part other than the ring plate 58 and the detection piece 62.

DESCRIPTION OF SYMBOLS 1 ... Processing module 15 ... Chuck apparatus 27 ... Movable side coil 28 ... Fixed side coil 31 ... Main shaft 41 ... Base block 45 ... Cylinder member 46 ... Piston 47 ... Clamp flow path 48 ... Unclamp flow path 51 ... Mandrel 53 ... Collet member 55 ... Cover member 55a ... Air discharge hole 56 ... Space 57 ... Detection rod 58 ... Ring plate 59 ... Spring 61 ... Clamp detection flow path 62 ... Detection piece 63 ... Space 65 ... Spring 66 ... Flow path for over clamp detection

Claims (4)

In a chuck device that includes a hydraulic cylinder inside the device main body and operates a clamping means connected to the piston to switch between clamping and unclamping on the workpiece,
A clamp detection channel into which detection air is sent is formed in the apparatus body,
An air discharge hole communicating with the opening of the clamp detection flow path and the outside is provided for the space formed inside the apparatus main body,
A lid member that opens and closes the opening is formed to interlock with the piston ,
The apparatus body is formed with an overclamp detection flow path through which detection air is sent,
An over detection member capable of switching between the flow of detection air flowing from the over clamp detection flow path to the air discharge hole and blocking is provided for the space of the apparatus main body,
A chuck device characterized in that the flow of detection air in the overclamp detection flow path is blocked by switching of the over detection member accompanying displacement of the piston during overclamping. The opening is closed by the lid member biased by a biasing member,
A detection rod having an end inserted in the space is fixed to the piston,
Due to the displacement when the piston is unclamped, the lid member is moved by the hook member provided at the end of the detection rod, and the opening is opened,
The lid member is released from the hooking member provided at the end of the detection rod by the displacement at the time of clamping of the piston, and the opening is closed by the biasing force of the biasing member. The chuck device according to claim 1 , wherein: The clamp means operates a collet member that performs clamping and unclamping on a workpiece via a tapered portion of a mandrel fixed to the piston.
The detection rod passes through a through-hole formed in the axial center portion of the piston and mandrel, is fixed by screwing with a screw portion formed in the piston, and has a rotation transmission portion formed on an end surface The chuck device according to claim 2 , wherein: The over detection member is attached so as to divide between the first space where the air discharge hole is located and the second space where the opening of the over clamp detection flow path is located, and slides in the axial direction of the piston. And is formed with a through-hole that communicates the first space and the second space,
The piston is fixed with a detection rod having an end inserted into the first space,
4. The device according to claim 1 , wherein an end of the detection rod closes a through-hole of the over-detecting member due to displacement during over-clamping by the piston. 5. Chuck device.

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