JP6552352B2 - Thin wall chucking method - Google Patents

Description

  The present invention relates to a thin workpiece chucking method for chucking a thin workpiece with a chuck device when machining with a machine tool.

  As a chuck device for chucking thin-walled workpieces, a plurality of outer claws disposed in the chuck body at intervals in the circumferential direction, and a plurality of outer claws disposed at intervals inside the plurality of outer claws in the circumferential direction. The thing provided with and the inner nail | claw is known (for example, refer patent document 1). In this chuck device, the plurality of inner claws are provided with springs, and the plurality of inner claws are moved radially outward by the elastic force of the springs to act on the inside of the thin work. Further, a fluid pressure circuit mechanism is provided in association with the plurality of outer claws, and the plurality of outer claws are moved radially inward by the fluid pressure of the fluid pressure circuit mechanism to act on the outside of the thin work.

  When chucking a thin workpiece, first, the inside of the thin workpiece is supported by a plurality of inner claws, and this support is performed with a weak force using the elastic force of the spring. The outer side is held, and this holding is performed with a strong force using the fluid pressure of the fluid pressure circuit mechanism, and is mainly held by the plurality of outer claws during processing.

JP 7-156005 A

  However, this chuck device has the following problems to be solved. First, since the plurality of inner claws are disposed inside the thin-walled work, when the inner diameter of the thin-walled work is reduced, the plurality of inner claws must be reduced, and the thin-walled inner diameter is relatively small. It becomes difficult to apply to the workpiece. Second, when supporting a thin-walled work by a plurality of inner claws, the elastic force of the spring provided on each inner claw is utilized, so that the force of each inner claw acting on the thin-walled work is made uniform. It is difficult and when the acting force of the inner claws is not uniform, it becomes difficult to position the thin-walled work at a desired position and hold it by a plurality of outer claws.

  An object of the present invention is to provide a method for chucking a thin-walled work that can position and hold the thin-walled work at a desired position.

According to a first aspect of the present invention , there is provided a chucking method for a thin-walled work according to a first aspect of the present invention , a chuck body rotationally driven integrally with a spindle, circumferentially spaced and spaced radially from the chuck body. A chuck apparatus comprising: a plurality of supported first claw members; and a plurality of second claw members disposed between the plurality of first claw members and supported by the chuck main body movably in the radial direction. A chucking method for thin-walled workpieces using the thin-walled workpiece chucking,
A first cylinder mechanism for moving the plurality of first claw members in the radial direction; a second cylinder mechanism for moving the plurality of second claw members in the radial direction; A first fluid pressure circuit mechanism for supplying a pressure fluid of one pressure and a second fluid pressure circuit mechanism for supplying a pressure fluid of a second pressure lower than the first pressure;
When holding a thin workpiece, the pressure fluid from the second fluid pressure circuit mechanism is supplied to the second cylinder mechanism, and the plurality of second claw members are moved inward in the radial direction by the second cylinder mechanism. The thin workpiece is positioned, and then the pressure fluid from the first fluid pressure circuit mechanism is supplied to the first cylinder mechanism in a state where the pressure fluid from the second fluid pressure circuit mechanism is supplied to the second cylinder mechanism. And the first cylinder mechanism moves the plurality of first claw members inward in the radial direction to sandwich and hold the thin workpiece, and then the pressure fluid from the first fluid pressure circuit mechanism is Supplying to the second cylinder mechanism and causing the pressure fluid from the first fluid pressure circuit mechanism to act on the plurality of second claw members and the plurality of first claw members to sandwich and hold the thin workpiece. And features.

In the method for chucking a thin-walled work according to a second aspect of the present invention, the holding and holding surfaces of the plurality of first claw members extend in an arc shape corresponding to the outer shape of the thin-walled work A part of the holding and holding surface is characterized in that a holding pressure relief recess extending in an arc-like direction is provided.

In the method for chucking a thin-walled work according to a third aspect of the present invention, the positioning surfaces of the plurality of second claw members extend in an arc shape corresponding to the outer shape of the thin-walled work A positioning pressure relief recess extending in an arc-like direction is provided on a part of the positioning surface.

Further, according to a fourth aspect of the present invention, there is provided a chucking method for a thin-walled work according to a fourth aspect of the present invention, a chuck main body rotationally driven integrally with a spindle, the chuck arranged circumferentially at intervals and radially movable. A chuck comprising a plurality of first claw members supported by a main body, and a plurality of second claw members disposed between the plurality of first claw members and movably supported in the radial direction by the chuck main body A chucking method for thin-walled workpieces, in which thin-walled workpieces are chucked using an apparatus
A first cylinder mechanism for moving the plurality of first claw members in the radial direction is provided, and a second cylinder mechanism for moving the plurality of second claw members in the radial direction is provided. A pressure fluid of a first pressure is supplied to the cylinder mechanism, and a pressure fluid of the first pressure and a pressure fluid of a second pressure lower than the first pressure are supplied to the second cylinder mechanism. Configure
When holding the thin workpiece, the pressure fluid of the second pressure is supplied to the second cylinder mechanism, and the plurality of second claw members are moved inward in the radial direction by the second cylinder mechanism to thereby move the thin workpiece. Then, in a state where the pressure fluid of the second pressure is supplied to the second cylinder mechanism, the pressure fluid of the first pressure is supplied to the first cylinder mechanism, and the plurality of the fluids are supplied by the first cylinder mechanism. The first claw member is moved inward in the radial direction to sandwich and hold the thin workpiece, and then the first pressure fluid is supplied to the second cylinder mechanism, and the first pressure fluid is supplied to the second cylinder mechanism. The plurality of second claw members and the plurality of first claw members act to hold and hold the thin work.

Further, according to a fifth aspect of the present invention, there is provided a chucking method for a thin-walled work according to a fifth aspect of the present invention, a chuck main body rotationally driven integrally with a spindle, the chuck arranged circumferentially at intervals and radially movable. A chuck comprising a plurality of first claw members supported by a main body, and a plurality of second claw members disposed between the plurality of first claw members and movably supported in the radial direction by the chuck main body A chucking method for thin-walled workpieces, in which thin-walled workpieces are chucked using an apparatus
A first cylinder mechanism for moving the plurality of first claw members in the radial direction to hold the thin workpiece is provided, and the plurality of second claw members are moved in the radial direction to move the thin workpiece. Provide a second cylinder mechanism for holding
Further, a first fluid pressure circuit mechanism is provided in association with the first cylinder mechanism, and a first fluid is supplied to the plurality of first claw members via the first cylinder mechanism by pressure fluid from the first fluid pressure circuit mechanism. Further, a second fluid pressure circuit mechanism is provided in association with the second cylinder mechanism, and a pressure fluid from the second fluid pressure circuit mechanism is interposed through the second cylinder mechanism. The first holding and holding force and a second holding pressure smaller than the first holding pressure are applied to the plurality of second claw members.
When holding a thin workpiece, the second cylinder mechanism moves the plurality of second claw members inward in the radial direction to position the thin workpiece with the second clamping holding force, and then the thin workpiece. In the state where the second holding force is positioned and held, the first cylinder mechanism moves the plurality of first claw members inward in the radial direction to hold the thin workpiece with the first holding force. And holding the thin workpiece with the first clamping holding force by causing the second cylinder mechanism to act on the plurality of second claw members in a state where the thin workpiece is clamped and held with the first clamping holding force. Holding and holding.

According to the thin workpiece chucking method of the first and fourth aspects of the present invention , when the thin workpiece is held, the pressure fluid of the second pressure is supplied to the second cylinder mechanism, and then the second pressure is applied. In the state where the pressure fluid of the first pressure is supplied to the second cylinder mechanism, the pressure fluid of the first pressure higher than the second pressure is supplied to the first cylinder mechanism, and then the pressure fluid of the first pressure is supplied to the first cylinder mechanism. The pressure fluid of the first pressure is supplied to the second cylinder mechanism while being supplied to the second cylinder mechanism. When the pressure fluid of the second pressure from the second cylinder mechanism is supplied, the workpiece can be positioned and held with a low pressure by the second claw member as described above, and the first pressure higher than the second pressure can be obtained. When the pressure fluid is supplied to the first cylinder mechanism, as described above, the thin workpiece can be held and held by the high pressure of the first claw member while suppressing the deformation of the thin workpiece with the second claw member. it can. Furthermore, when the pressure fluid of the first pressure is supplied to the second cylinder mechanism, the second claw member is also held at a high pressure in a state of being held and held by the first claw member, and as a result, the first and second The thin workpiece can be held more securely by the claw members.

Further, according to the processing method of thin workpieces according to claim 2 of the present invention, since the holding pressure relief recess extending arcuately direction on a part of the clamping holding surface of the first pawl member is provided, the thin workpiece The holding pressure relief recess can release some deformation that may occur when holding and holding.

Further , according to the method for chucking a thin-walled work according to claim 3 of the present invention, since a positioning pressure relief recess extending in an arc-like direction is provided in a part of the positioning surface of the second claw member The positioning pressure relief recess can release some deformation that may occur when positioning and holding the.

Furthermore, according to the thin-walled workpiece chucking method according to claim 5 of the present invention, when holding the thin-walled workpiece, the plurality of second claw members are moved inward in the radial direction by the second cylinder mechanism Since the work is positioned with a second holding force smaller than the first holding force, the thin work can be held in position without deformation. Then, in the state of being positioned in this manner, the plurality of first claw members are moved radially inward by the first cylinder mechanism to hold and hold the thin work with the first holding force, and thereafter, the thin work Since the thin workpiece is clamped and held by the first clamping holding force by acting on the plurality of second claw members by the second cylinder mechanism in the state of being clamped and held by one clamping holding force, the thin workpiece is securely held and held. Can.

The front view which shows an example of the chuck | zipper structure to which the chucking method of the thin workpiece | work according to this invention is applied. Sectional drawing which shows the chuck | zipper structure of FIG. 1 in the state holding the thin workpiece | work. Sectional drawing corresponding to FIG. 2 which shows the chuck | zipper structure of FIG. 1 in the state (The 1st and 2nd nail | claw member is an open state) which is not holding the thin workpiece | work. Sectional drawing which shows a part of 2nd fluid pressure circuit mechanism in the chuck | zipper structure of FIG. FIG. 7 is a simplified view for explaining a chucking method using the chuck device of FIG. 1; The partial front view which shows the front-end | tip part of a 1st nail | claw member. FIG. 6 is a fluid circuit diagram showing an example of a fluid control system applied to the chuck structure of FIG. 1 when the first and second claw members are held in an open state. FIG. 8 is a fluid circuit diagram showing the flow of pressure fluid when a thin workpiece is positioned and held by the second claw member in the fluid control system of FIG. 7. FIG. 8 is a fluid circuit diagram showing a flow of pressure fluid when a thin workpiece is sandwiched and held by a first claw member in the fluid control system of FIG. 7. FIG. 8 is a fluid circuit diagram showing a flow of pressure fluid when holding and holding a thin-walled work by the first and second claw members in the fluid control system of FIG. 7;

  An embodiment of a chucking method according to the present invention will be described below with reference to the attached drawings, applied to a chuck device of an NC lathe. In FIGS. 1 and 2, the illustrated chuck device 2 includes a chuck body 4 on which a thin workpiece W as a workpiece is mounted, and a spindle 6 that rotates integrally with the chuck body 4, and this spindle 6 is rotatably supported by the spindle housing via bearing means, and is rotationally driven by the rotational power from an electric motor as a drive source.

  The chuck body 4 comprises a chuck body 8 attached to the front (right side in FIG. 2) side of the spindle 6 and a chuck housing 10 attached to the front (right side in FIG. 2) side of the chuck body 8. The chucking claw means 12 is disposed on the front side of the chuck housing 10. The chucking claw means 12 is provided on the front side of the chuck housing 10 at substantially equal intervals in the circumferential direction (that is, at intervals of 120 degrees in the circumferential direction). A first claw member 14 and a plurality of (in this embodiment, three) second claw members 16 disposed between the first claw members 14 (in this embodiment, in the middle of the adjacent first claw members 14) It consists of A first cylinder mechanism 18 for moving the first claw members 14 is provided corresponding to the plurality of first claw members 14, and these corresponding to the plurality of second claw members 16. A second cylinder mechanism 20 for moving the second claw member 16 is provided.

  In this embodiment, the first cylinder mechanism 18 is provided corresponding to each of the plurality of first claw members 14, and the cylinder 22 side of each first cylinder mechanism 18 is attached to the front surface of the chuck housing 10, and the output rod 24 side thereof. The first claw member 14 corresponding to is attached. Accordingly, when a pressure fluid is supplied to the expansion side of the first cylinder mechanism 18 as will be described later, the output rod 24 expands to move the first claw member 14 radially inward, and the first cylinder mechanism. When pressure fluid is supplied to the contraction side of 18, the output rod 24 contracts and the first claw member 14 moves radially outward.

  Further, one second cylinder mechanism 20 is provided corresponding to the plurality of second claw members 16, and the cylinder body 30 is attached to the rear end surface (the left end surface in FIG. 2) of the spindle 6. A piston 32 (see FIG. 4) accommodated movably in the axial direction (left and right direction in FIG. 2) is drivingly connected to the plurality of second claw members 16 via a movement transmission mechanism 34 described later. Therefore, when the pressure fluid is supplied to the extension side of the second cylinder mechanism 20 as described later, the piston 32 moves to the right in FIGS. 2 and 4 and the second claw member via the movement transmission mechanism 34 When the pressure fluid is supplied to the contraction side of the second cylinder mechanism 20, the piston 32 moves to the left in FIGS. 2 and 4 via the movement transmission mechanism 34. Thus, the second claw member 16 moves inward in the radial direction.

  In this embodiment, the illustrated second claw member 16 includes a parent claw portion 35 that is mounted on the chuck housing 10 so as to be movable in the radial direction, and a child claw portion 36 is provided at the radially inner tip of the parent claw portion 35. It is attached. In addition, a support connection portion 38 is attached to the back side of the parent claw portion 35, and the support connection portion 38 is connected to the movement transmission mechanism 34.

  Referring mainly to FIGS. 2 and 3, the illustrated movement transmitting mechanism 34 includes a hollow movement rod 40 axially movably disposed through the cylinder body 30 of the second cylinder mechanism 20, A hollow intermediate connecting member 42 is mounted on the tip (right end in FIGS. 2 and 3) side of the moving rod 40, and a hollow driving member 44 on the tip (right end in FIGS. 2 and 3) side of the intermediate connecting member 42. The distal end side of the drive member 44 is movably supported on the outer peripheral surface of a support sleeve 46 mounted on the back surface of the chuck housing 10. Further, the rear end (left end in FIGS. 2 and 3) side is movably supported by the protrusion 48 of the cylinder body 30.

  Furthermore, rocking members 50 are disposed in the chuck body 8 corresponding to the respective second claw members 16, and each rocking member 50 is rockably supported via a shaft member 52. An annular receiving groove 54 is provided on the outer peripheral surface of the driving member 44, and the tip end portion of the first arm 56 of each swinging member 50 is rotatably received in the annular receiving groove 54. Also, a receiving groove 58 is provided on the back of the support connecting portion 38 of each second claw member 16, and the tip of the second arm 60 of the corresponding swing member 50 is in the receiving groove 58 of the second claw member 16. It is pivotably received.

  With this configuration, when the pressure fluid is supplied to the extension side of the second cylinder mechanism 20 as described later, the piston 32 (see FIG. 4) approaches the right side (chuck main body 4) in FIG. The moving rod 40, the intermediate connecting member 42 and the driving member 44 move as shown in FIG. When the drive member 44 moves in this manner, the plurality of rocking members 50 simultaneously rock in the direction indicated by the arrow 62 (see FIG. 3) along with the movement, and the corresponding second claw members 16 The plurality of second claw members 16 move radially outward, and are held in the open state (that is, the state in which the thin work W is received) shown in FIG. 3. When pressure fluid is supplied to the contraction side of the second cylinder mechanism 20, the piston 32 moves to the left in FIG. 4 (in the direction away from the chuck body 4), and moves along with the movement of the piston 32. The rod 40, the intermediate connection member 42 and the drive member 44 move to be retracted as shown in FIG. When the drive member 44 moves in this manner, the plurality of rocking members 50 simultaneously rock in the direction indicated by the arrow 64 (see FIG. 2) along with the movement, and the corresponding second claw members 16 The plurality of second claw members 16 are moved radially inward and held in the holding state shown in FIG. 2 (that is, the state in which the thin work W is always held).

  In this embodiment, a first fluid pressure circuit mechanism 72 for supplying a pressure fluid of a first pressure (for example, about 0.2 to 0.7 Mpa) is provided in association with the plurality of first cylinder mechanisms 18. The first fluid pressure circuit mechanism 72 includes a first circuit connection member 74, and a second pressure (e.g., 0.1 to 0) lower than the first pressure in relation to the second cylinder mechanism 20. The second fluid pressure circuit mechanism 76 includes a second circuit connection member 78. The second fluid pressure circuit mechanism 76 is provided with a second fluid pressure circuit mechanism 76 for supplying a pressure fluid (about 5 MPa). In this embodiment, the second circuit connecting member 78 is attached to the projecting portion 48 of the cylinder body 30 of the second cylinder mechanism 20, and the first circuit connecting member 74 is attached to the rear end of the second circuit connecting member 78. ing.

  The first circuit connection member 74 is provided with a contraction side upstream flow passage portion 80 and an expansion side upstream flow passage portion 82, and the contraction side upstream flow passage portion 80 is provided with a contraction side port 84. Is provided with an extension side port 86. Further, the first fluid pressure circuit mechanism 72 has a contraction-side intermediate flow defined inward in the radial direction of the above-described movement transmission mechanism 34 (specifically, the moving rod 40, the intermediate coupling member 42, and the drive member 44). The passage portion 88, the extension side intermediate passage portion 90, the contraction side downstream passage portion 92 provided in the chuck housing 10 of the chuck body 4 and the extension side downstream passage portion provided in the chuck housing 10 and the support sleeve 46 The contraction-side upstream flow passage portion 80, the contraction-side intermediate flow passage portion 88, and the contraction-side downstream flow passage portion 92 constitute a part of the first contraction-side flow passage, and the extension-side upstream flow passage portion 82, the extension side intermediate flow path part 90 and the extension side downstream flow path part 94 constitute a part of the first extension side flow path.

  More specifically, in this embodiment, the contraction side intermediate flow passage portion 88 is defined radially inward of the first inner pipe member 96 and the second inner pipe member 98 connected to each other, and The end portion is supported by the contraction side upper flow passage portion 80 of the first circuit connection member 74, the second inner pipe member 98 is supported by the inner peripheral surface of the support sleeve 46, and the second inner pipe member 98 and the chuck housing 10 A contraction side space flow passage portion 100 is provided therebetween, and the contraction side downstream flow passage portion 92 of each first cylinder mechanism 18 is in communication with the contraction side space flow passage portion 100. Further, the extension-side intermediate flow passage portion 90 is defined by using an outer pipe member 102 and the like disposed radially outside the first inner pipe member 96, and the end of the outer pipe member 100 is a first circuit. It is supported by the extension side upstream channel part 82 of the connecting member 74, and the other end side is supported by the large inner diameter part provided in the large diameter part 104 of the second inner pipe member 98, the first inner pipe member 96 and the first outer side. An annular space 10 between the pipe member 100, a through flow passage end 106 provided in the large diameter portion 104 of the first inner pipe member 98, and a space between the second inner pipe member 98 and the intermediate connection member 42 It consists of an annular space. An extension-side annular space channel 108 is provided between the intermediate connecting member 42 and the support sleeve 46, and the extension-side downstream channel 94 of each first cylinder mechanism 18 is connected to the extension-side annular space channel 108. It is communicated to.

  Mainly referring to FIG. 4, the second circuit connection member 78 is provided with a contraction side upstream flow passage portion 112 and an extension side upstream flow passage portion 114, and the contraction side upstream flow passage portion 112 is provided with a contraction side port 116. The extension side port 118 is provided in the extension side upstream flow path 114. Further, the second fluid pressure circuit mechanism 76 includes a contraction side downstream flow passage portion 120 and an extension side downstream flow passage portion 122 provided in the cylinder main body 30 of the second cylinder mechanism 20, and the expansion and contraction side upstream flow passage portion 112. Is connected to the expansion / contraction side downstream flow path section 120, the expansion side upstream flow path section 114 is connected to the expansion side downstream flow path section 122, and the contraction side upstream flow path section 112 and the contraction side downstream flow path section 120 are second. A part of the contraction side channel (see FIG. 7) constitutes a part, and the extension side upstream channel part 114 and the extension side downstream channel part 122 constitute a part of the second extension side channel (see FIG. 7).

  The chucking of the thin work W by the above-described chuck device is performed, for example, as follows. Referring to FIGS. 2 to 5, in order to perform chucking, first, as shown in FIG. 5A, a radial central region of the chuck body 4 (that is, the plurality of first claw members 14 and the plurality of The thin work W to be processed is positioned on the center area of the double claw member 16 by a loader device (not shown) or the like (position process of the thin work). Then, in this positioned state, the pressure fluid (for example, pressure oil) from the pressure fluid source (not shown) of the second fluid pressure circuit mechanism 76 is supplied to the contraction side of the second cylinder mechanism 20. .

  When supplied in this manner, the pressure fluid from the pressure fluid supply source (not shown) is supplied to the contraction side port 116 of the second circuit connecting member 78 as shown in FIGS. It is supplied to the contraction side of the second cylinder mechanism 20 through the passage portion 112 and the contraction side downstream flow passage portion 120 (that is, the second contraction side flow passage). Thus, when the pressure fluid is supplied to the contraction side of the second cylinder mechanism 20, the piston 32 moves to the contraction side on the left in FIG. 4, and the movement of the piston 32 moves the moving rod 40 and the intermediate connection member. The plurality of swinging members 50 swings in the direction indicated by the arrow 64 (see FIG. 2) via the drive member 44 and the driving member 44, and the corresponding second claw member 16 moves radially inward by the swinging, As shown in FIG. 5 (b), the plurality of second claw members 16 position and hold the thin work W (position holding process of the thin work).

  In addition, when the pressure fluid is supplied to the contraction side of the second cylinder mechanism 20, the fluid from the extension side of the second cylinder mechanism 20 is the extension side downstream channel part 122 and the extension side upstream channel part 114 (that is, the second extension side). Through the flow path, and from the extension port 118 back to the pressure fluid source (not shown).

  In this positioning and holding state, since the pressure fluid acts on the piston 32 of the second cylinder mechanism 30 from the second fluid pressure circuit mechanism 76 with the low second pressure P2, the thin workpiece W is positioned and held with a small pressure. Thus, deformation of the thin workpiece W during positioning and holding can be suppressed.

  After that, in the state of being positioned and held in this manner, the pressure fluid (for example, pressure oil) from the pressure fluid source (not shown) of the first fluid pressure circuit mechanism 72 is supplied to the extension side of the first cylinder mechanism 18 Do. When supplied in this manner, the pressure fluid from the pressure fluid source (not shown) is supplied to the extension side port 86 of the first circuit connection member 74, as shown in FIG. Through the extension side intermediate flow passage portion 90 to the extension side annular space flow passage portion 108, and from the extension side annular space flow passage portion 108 through the corresponding extension side downstream flow passage portion 94 (that is, through the first extension side flow passage). ) It is supplied to the extending side of each first cylinder mechanism 18. Thus, when the pressure fluid is supplied to the plurality of first cylinder mechanisms 18, their output rods 24 extend and the first claw members 14 move radially inward, as shown in FIG. 5 (c). As described above, the plurality of first claw members 14 sandwich and hold the thin workpiece W (a thin workpiece sandwiching and holding step).

  In addition, when the plurality of first cylinder mechanisms 18 extend, the fluid from the contraction side thereof flows in the contraction side downstream flow passage portion 92, the contraction side space passage portion 100, the contraction side intermediate flow passage portion 88, and the contraction side upstream flow. The passage 80 (that is, the first contraction side flow path) is passed through and returns from the contraction side port 84 to the pressure fluid supply source (not shown).

  After that, in the state of being positioned and held in this way, the pressure fluid (for example, pressure oil) from the pressure fluid source (not shown) of the second fluid pressure circuit mechanism 76 is supplied to the contraction side of the second cylinder mechanism 20 Do.

  In this holding and holding state, since the pressure fluid acts on the extension side of the first cylinder mechanism 18 with the first pressure P1 of the high pressure from the first fluid pressure circuit mechanism 72, the thin work W is held and held with a large pressure. Thus, the thin workpiece W can be reliably held and held. Further, when holding and holding by the plurality of first claw members 14, since the plurality of second claw members 16 act on the outer peripheral surface of the thin work W, the holding is surely performed while suppressing the deformation of the thin work W Can be held.

  For example, in order to finish the processing on the thin workpiece W, the pressure fluid of the first fluid pressure circuit mechanism 72 is supplied to the contraction side of the first cylinder mechanism 18 and the pressure fluid of the second fluid pressure circuit mechanism 76 is supplied. What is necessary is just to supply to the 2nd cylinder mechanism 20 expansion | extension side.

  When the pressure fluid from the first fluid pressure circuit mechanism 72 is supplied in this way, the pressure fluid from the pressure fluid source (not shown) is contracted on the contraction side of the first circuit connection member 74 as shown in FIG. It is supplied to the port 84 and flows to the contraction side space channel portion 100 through the contraction side upstream channel portion 80 and the contraction side intermediate channel portion 88. The pressure fluid thus supplied is supplied from the contraction side space flow passage portion 100 to the contraction side of each first cylinder mechanism 18 through the corresponding contraction side downstream flow passage portion 92 (that is, through the first contraction side flow passage). The output rods 24 contract to move the first claw members 14 radially outward, and the plurality of first claw members 14 open the thin workpiece W as shown in FIG. 5A. Will be held by At this time, the fluid on the extension side of each first cylinder mechanism 18 is the extension-side downstream passage portion 94, the extension-side annular space passage portion 108, the extension-side intermediate passage portion 90, and the extension-side upstream passage portion 82. And is returned through the extension side port 86 (ie, the first extension side channel).

  Also, when the pressure fluid from the second fluid pressure circuit mechanism 76 is supplied in this manner, the pressure fluid from the pressure fluid source (not shown) is supplied to the second circuit connection member 78, as shown in FIG. It is supplied to the extension side port 118 and supplied to the extension side of the second cylinder mechanism 20 through the extension side upstream channel portion 114 and the extension side downstream channel portion 122 (that is, the second extension side channel), and its piston 32 is In FIG. 4, it moves to the right extension side. The movement of the piston 32 causes the plurality of swinging members 50 to swing in the direction indicated by the arrow 62 (see FIG. 3) via the moving rod 40, the intermediate connecting member 42, and the driving member 44. The two claw members 16 move radially outward, and as shown in FIG. 5A, the plurality of second claw members 16 are held in the open state in which the thin work W is released. At this time, the contraction side fluid of the second cylinder mechanism 20 is returned through the contraction side downstream flow path portion 120, the contraction side upstream flow path portion 112, and the contraction side port 116 (that is, the second contraction side flow path) .

  As mentioned above, although one example of the chucking method according to the present invention is applied to the chuck device of the NC lathe, the present invention is not limited to such an example, and various examples can be made without departing from the scope of the present invention. Can be changed or modified.

  For example, in the embodiment described above, the thin work W is positioned and held by the plurality of second claw members 16 (positioning and holding process of the thin work), and thereafter held and held by the plurality of first claw members 14 (of the thin work After the sandwiching and holding process, the pressure fluid from the first fluid pressure circuit mechanism 72 (ie, the pressure fluid of the first pressure P1) is further transferred to the contraction side port 116 of the second circuit connection member 76 after the sandwiching and holding process). You may make it supply (2nd clamping holding process of a thin workpiece).

  When this second holding and holding step is performed, as understood from the above description, the pressure fluid from the first fluid pressure circuit mechanism 72 is supplied to the contraction side of the second cylinder mechanism 20, and the first pressure fluid is The pressure P1 acts on the piston 32 of the second cylinder mechanism 20, and the pressure acting on the piston 32 acts the second claw member 16 on the thin-walled work W. As a result, the thin-walled work W becomes the first claw member 14 Thus, the thin workpiece W can be held and held more reliably by the second claw members 16 as well. The supply control of pressure fluid to the first and second cylinder mechanisms 18 and 20 may be controlled using a pressure fluid control system described later.

  In the embodiment described above, as shown in FIG. 1 etc., the shape of the tip end face of the first claw member 14 is formed in an arc corresponding to the outer shape (that is, the outer peripheral shape) of the thin work W to be chucked. Although substantially the entire area of the tip end surface of the first claw member 14 acts on the outer peripheral surface of the thin work W to be held and held, instead of such a configuration, it is configured as shown in FIG. It can also be done. In FIG. 6, in this modification, the tip end face of the first claw member 14A is formed in an arc shape corresponding to the outer shape of the thin work W, and a part of the arc tip end face in the arc direction (in this embodiment (An intermediate portion thereof) is provided with a recess extending in the arc direction, that is, a holding pressure relief recess 140, and by providing such a holding pressure relief recess 140, the holding action portions are provided at both arc direction end portions of the arcuate tip surface. 142 and 144 exist, and these holding action portions 142 and 144 act on the outer peripheral surface of the thin workpiece W to hold and hold them.

  When such a first claw member 14A is used, the tip end face of the first claw member 14A does not act on the thin work W over a wide range, and therefore, this thin work W is applied when slight deformation occurs. The pressure can be released by the holding pressure release recess 140, and large deformation of the thin work W can be suppressed when holding and holding it with a large force.

  In this modified embodiment, the first claw member 14A is provided with a concave portion (holding pressure relief concave portion), but such a concave portion can be similarly provided on the tip surface of the second claw member 16 as well. In this case, a concave portion extending in the arc direction, that is, a part (for example, an intermediate portion thereof) in the arc direction of the arc tip end face (the arc tip end face corresponding to the outer shape of the thin work W) of the second hook member Positioning pressure relief depressions are provided, and by providing such positioning pressure relief depressions, positioning action portions are present at both ends in the arc direction of the circular arc tip surface, and these positioning action portions are on the outer peripheral surface of thin work W Acts and holds the positioning. With this configuration, when the thin workpiece W is slightly deformed, the pressure can be released by the positioning pressure relief recess, and the thin workpiece W can be prevented from being greatly deformed during positioning and holding. it can.

  Moreover, in the embodiment described above, a liquid (for example, pressure oil) is used as the pressure fluid, but instead of the liquid, a gas (for example, compressed air) may be used.

  Furthermore, in the embodiment described above, the plurality of first claw members 14 are moved by the first cylinder mechanism 18 provided corresponding to each of them, and the plurality of second claw members 16 correspond to them. The second cylinder mechanism 20 is moved by one second cylinder mechanism 20 provided, but in contrast to such a configuration, for the plurality of second claw members 16, the second cylinder mechanism is corresponding to each of them. A plurality of first claw members 14 may be provided and moved, and a single first cylinder mechanism may be provided corresponding to them and simultaneously moved.

  Furthermore, such a chucking method can be applied to a normal NC lathe or the like. That is, for example, a plurality of claw members supported by a chucking main body of an NC lathe function as a first claw member, and a plurality of second claw members and a second one are separated from the plurality of first claw members. A cylinder mechanism may be provided, and a second fluid pressure circuit mechanism may be provided in association with the second cylinder mechanism. Thus, the second fluid pressure circuit mechanism, the second cylinder mechanism, and the second claw member are added. By doing so, it can be applied to a normal NC lathe.

  Such a chucking device 2 may be controlled by a pressure fluid control system shown in FIGS. Referring mainly to FIG. 7, the illustrated pressure fluid control system 202 includes a first fluid supply control system 204 for controlling a plurality of first cylinder mechanisms 18A (only one is shown in FIGS. 7 to 10), The second fluid supply control system 206 for controlling the plurality of second cylinder mechanisms 20A (only one is shown in FIGS. 7 to 10) and the first and second fluid supply control systems 204 and 206 supply pressure fluid A pressure fluid source 208, which includes a fluid tank 210 for storing fluid, and a fluid pump 212 for supplying fluid in the fluid tank 210 as pressure fluid. There is.

  First, the first fluid supply control system 204 will be described. The first fluid supply control system 204 includes a first fluid supply channel 214 connected to the fluid pump 212 and a first fluid return connected to the fluid tank 210. A flow path 216, a first contraction side flow path 218 connected to the contraction side of the first cylinder mechanism 18A, and a first expansion side flow path 220 connected to the expansion side of the first cylinder mechanism 18A are provided. . A first pressure reducing valve 217 is disposed in the first fluid supply flow channel 214, and the first pressure reducing valve 217 sets the pressure of the fluid flowing through the first fluid supply flow channel 214 to a first pressure P1 (for example, 0.2). To about 0.7 MPa).

  Also, between the first fluid supply flow channel 214 and the first fluid return flow channel 216, and the first contraction side flow channel 218 and the first extension side flow channel 220, a first flow channel switching for switching the flow channel A valve 222 (for example, composed of an electromagnetic switching valve) is provided. The first flow passage switching valve 222 is selectively positioned at a first switching position shown in FIGS. 7 and 8 and a second switching position shown in FIGS. 9 and 10.

  When the first flow passage switching valve 222 is positioned at the first switching position, the first supply flow passage 214 and the first contraction flow passage 218 are in communication with each other, and the first pressure P1 from the pressure fluid supply source 208 Pressure fluid is supplied to the contraction side of the first cylinder mechanism 18A through the first fluid supply flow passage 214 and the first contraction side flow passage 218, and the first fluid return flow passage 216 and the first extension side flow passage 220. And the pressure fluid on the extension side of the first cylinder mechanism 18A is returned to the fluid tank 210 through the first extension side flow passage 220 and the first fluid return flow passage 216, whereby the first cylinder mechanism 18A is contracted. Be done. In addition, when the first flow passage switching valve 222 is positioned at the second switching position, the first supply flow passage 214 and the first extension flow passage 220 are in communication with each other, and the first pressure from the pressure fluid supply source 208 The pressure fluid P1 is supplied to the extension side of the first cylinder mechanism 18A through the first fluid supply channel 214 and the first extension channel 220, and the first fluid return channel 216 and the first contraction channel 218, and the pressure fluid on the contraction side of the first cylinder mechanism 18A is returned to the fluid tank 210 through the first contraction side flow path 218 and the first fluid return flow path 216, whereby the first cylinder mechanism 18A is The plurality of first claw members (not shown) hold and hold the thin-walled work by the first holding and holding force, as described later.

  Next, the second fluid supply control system 206 will be described. The second fluid supply control system 206 functions as a pressure fluid supply source 208 (as described above, functioning as a pressure fluid supply source for the first fluid supply control system 204). And the second fluid return channel 226 connected to the fluid tank 210 of the pressure fluid source 208, and on the contraction side of the second cylinder mechanism 20A. The pressure of the pressure fluid flowing through the second contraction side flow path 228 connected, the second expansion side flow path 230 connected to the expansion side of the second cylinder mechanism 20A, and the second fluid supply flow path 224 is switched and controlled. A pair of intermediate fluid flow paths 232 and 234.

  The second fluid supply flow passage 224 is provided with a second pressure reducing valve 236 and a third pressure reducing valve 238. The second pressure reducing valve 236 is configured to adjust the pressure of the pressure fluid flowing through the second fluid supply flow passage 224 to a first pressure. The third pressure reducing valve is for setting the pressure P1, and the second pressure P2 (for example, 0.1 to 0.5 MPa) in which the pressure of the pressure fluid flowing in the second fluid supply flow path is lower than the first pressure. To set the degree).

  Further, a pressure switching valve 240 (for example, composed of an electromagnetic switching valve) is provided between the second fluid supply channel 224 and the second fluid return channel 226 and the pair of fluid intermediate channels 232 and 234. The pressure switching valve 240 is selectively positioned at the first switching position shown in FIGS. 7-9 and the second switching position shown in FIG. When the pressure switching valve 240 is in the first switching position, the second fluid supply channel 224 is connected to the pair of liquid intermediate channels 232 and 234, and the second fluid return channel 226 is the pair of liquid intermediate channels 232. , 234, the pressure fluid from the second fluid supply channel 224 is fed to the pair of fluid intermediate channels 232, 234. Also, when the pressure fluid switching valve 240 is in the second switching position, the second fluid supply flow path 224 is connected to one fluid intermediate flow path 234, and the pressure fluid from the second fluid supply flow path 224 is this fluid. The second fluid return flow path 246 is connected to the other fluid intermediate flow path 232 while being supplied to the intermediate flow path 234, and the pressure fluid in the fluid intermediate flow path 232 flows through the second fluid return flow path 226. It is returned to the tank 210.

  Further, a branch channel 242 is provided in relation to the fluid intermediate channel 232, one end side of the branch channel 242 is connected to the fluid intermediate channel 232, and the other end side is connected to the third pressure reducing valve 238. . Further, a check valve 244 is provided at a predetermined portion of the fluid intermediate flow passage 232 (specifically, on the downstream side of the connection portion with the branch flow passage 242), and the check valve 244 flows out from the pressure fluid switching valve 240. Allow the pressure fluid to flow and block the flow of pressure fluid flowing into the pressure switching valve 240.

  A second flow path switching between the merging middle flow path 246 and the second fluid return flow path 226 where the pair of fluid middle flow paths 232 and 234 merge and the second contraction side flow path 228 and the second extension side flow path 230 A valve 248 (for example, composed of an electromagnetic switching valve) is provided. The second flow passage switching valve 248 is selectively positioned at a first switching position shown in FIG. 7 and a second switching position shown in FIGS.

  When the second flow path switching valve 248 is located at the first switching position, the merged intermediate flow path 246 and the second expansion side flow path 230 are connected, and the pressure fluid from the merged intermediate flow path 246 is second expanded. The pressure is supplied to the extension side of the second cylinder mechanism 20A through the side flow passage 230, the second contraction side flow passage 228 and the second fluid return passage 226 are connected, and the pressure on the contraction side of the second cylinder mechanism 20A. The fluid is returned to the fluid tank 210 through the second contraction side flow passage 228 and the second fluid return flow passage 226, whereby the second cylinder mechanism 20A is stretched. When the second flow path switching valve 248 is located at the second switching position, the merged intermediate flow path 246 and the second contraction side flow path 228 are connected, and the pressure fluid from the merged intermediate flow path 246 is second. The pressure is supplied to the contraction side of the second cylinder mechanism 20A through the contraction side flow passage 228, and the second extension side flow passage 230 is connected to the second fluid return passage 226, and the pressure on the extension side of the second cylinder mechanism 20A. The fluid is returned to the fluid tank 210, whereby the second cylinder mechanism 20A is contracted. At this time, when a pressure fluid having a second pressure P2 smaller than the first pressure P1 is fed through the merged intermediate flow path 246, the plurality of second claw members (not shown) can handle the thin workpiece as described later. The plurality of second claw members will be described later when the pressure fluid of the first pressure is supplied through the merging intermediate flow path 246 while holding and holding with a second holding force smaller than the first holding force, Thus, the thin work is held and held by the first holding force.

  Chucking of a thin-walled work using this pressure fluid control system is performed as follows. In the state before chucking the thin-walled work, the first and second flow path switching valves 222 and 248 and the pressure switching valve 240 are held in the state shown in FIG. 7. That is, the first flow path switching valve 222 is held at the first switching position, and the pressure fluid from the pressure fluid supply source 208 (pressure fluid set to the first pressure P1 by the first pressure reducing valve 217) is supplied to the first fluid. The pressure fluid is supplied to the contraction side of the first cylinder mechanism 18A through the flow path 214 and the first contraction side flow passage 218, and the pressure fluid on the extension side of the first cylinder mechanism 18A is the first extension side flow passage 220 and the second fluid. The fluid is returned to the fluid tank 210 through the return channel 216. Accordingly, the first cylinder mechanism 18A is contracted, and the first claw member (not shown) attached to the output rod of the first cylinder mechanism 18A is held in the radially outward moved open state.

  At this time, the pressure switching valve 240 is held at the first switching position, and the pressure fluid from the second fluid supply channel 224 is supplied to the pair of fluid intermediate channels 232 and 234, and the pressure flowing in the fluid intermediate channel 232 The fluid acts on the third pressure reducing valve 238 through the branch flow path 242, whereby the third pressure reducing valve 238 functions to set the pressure. At this time, the second flow passage switching valve 248 is held at the first switching position, and the pressure fluid from the merging intermediate flow passage 246 is fed to the extension side of the second cylinder mechanism 20A, and this second cylinder The pressure fluid on the contraction side of the mechanism 20A is returned to the fluid tank 210 through the second fluid return channel 226.

  Therefore, the pressure fluid supplied from the pressure fluid source 208 through the second fluid supply flow path 224 is set to the first pressure P 1 by flowing through the second pressure reducing valve 236, and then flows through the third pressure reducing valve 238. The pressure fluid of the second pressure P2 is set to the second pressure P2, and the pressure fluid of the second pressure P2 flows to the extension side of the second cylinder mechanism 20A through the pair of fluid middle channels 232 and 234, the merging middle channel 246 and the second extension side channel 230 Thus, the second cylinder mechanism 20A is extended and held in the open state in which the second claw member is moved radially outward as described above.

  In the process of positioning and holding a thin-walled work when chucking a thin-walled work, as shown in FIG. 8, the first flow passage switching valve 222 is held at the first switching position and the pressure switching valve 240 is held at the first switching position. In this state, the second channel switching valve 248 is switched to the second switching position. When switched in this way, the pressure fluid from the merging intermediate flow passage 246 is supplied to the contraction side of the second cylinder mechanism 20A, and the pressure fluid on the extension side of the second cylinder mechanism 20A is the second fluid return flow Return to fluid tank 210 through path 226. Therefore, after the pressure fluid from the pressure fluid source 208 is set to the second pressure P 2, the second cylinder mechanism 20 A passes through the pair of fluid intermediate flow passages 232 and 234, the merging intermediate flow passage 246 and the second contraction side flow passage 228. Thus, the second cylinder mechanism 20A is contracted, and the second claw member (not shown) moves radially inward as described above to move to the second pressure P2, in other words, The thin workpiece is positioned and held with a relatively small second holding force.

  Then, in the thin workpiece clamping process in which the thin workpiece is clamped and held by the first claw member, as shown in FIG. 9, the pressure switching valve 240 is at the first switching position and the second flow path switching valve 248 is at the first position. In the state held at the second switching position, the first flow path switching valve 222 is positioned at the second switching position. When switched in this way, the pressure fluid from the pressure fluid source 208 is set to the first pressure P1 and then delivered to the extension side of the first cylinder mechanism 18A through the first extension side flow passage 220, The contraction-side pressure fluid of the first cylinder mechanism 18A is returned to the fluid tank 210 through the first contraction-side flow path 218 and the first fluid return flow path 216, whereby the first cylinder mechanism 18A is expanded and the first pawl is extended. A member (not shown) holds and holds the thin-walled work positioned and held by the second claw member with the first pressure P1, in other words, a relatively large first holding and holding force.

  Further, in the subsequent second holding and holding process of the thin-walled work, as shown in FIG. 10, the first flow passage switching valve 222 is in the second switching position, and the second flow passage switching valve 248 is in the second switching position. In the held state, the pressure switching valve 240 is switched to the second switching position. When switched in this way, the pressure fluid in the fluid intermediate flow passage 232 and the branch flow passage 242 is returned to the fluid tank 210 through the second fluid return flow passage 226, and the third pressure reducing valve 238 is sent via the branch flow passage 242. The pressure of the pressure fluid acting on the pressure becomes substantially zero (zero), and the third pressure reducing valve 238 does not function. Therefore, the pressure fluid from the pressure fluid source 208 is set to the first pressure P1 by the second pressure reducing valve 236, and the pressure fluid flows through the fluid intermediate flow passage 234, the merging intermediate flow passage 246 and the second contraction side flow passage 228. The second claw member (not shown) is fed to the contraction side of the two-cylinder mechanism 20A so as to sandwich and hold the thin workpiece held and held by the first claw member. The second claw member holds and holds the first pressure P1, in other words, with a relatively high first holding force.

  To release the thin workpiece held and held by the chuck device (that is, the first and second claw members), as shown in FIG. 7, the first and second flow path switching valves 222 and 248 are set to the first switching position. At the same time, the pressure switching valve 240 may be positioned at the first switching position. At this time, the pressure switching valve 240 may be held at the second switching position.

  In the embodiment described above, the pressure fluid of the first pressure P1 is supplied to the first cylinder mechanism 18A, and the thin work is held and held by the first holding force by the plurality of first claw members (not shown). In addition, the second fluid mechanism 20A is supplied with a pressure fluid of the second pressure P2 (or the first pressure P1), and a plurality of second claw members (not shown) hold the thin workpiece with a second clamping holding force ( Alternatively, even when the sizes of the first cylinder 18A and the second cylinder 20A are changed, the first holding force and the first holding force by the first claw member are set. A desired effect can be achieved by maintaining the first and second holding force by the two claw members in the above-described relationship.

Reference Signs List 2 chuck device 4 chuck body 6 spindle 14 first claw member 16 second claw member 18, 18A first cylinder mechanism 20, 20A second cylinder mechanism 34 movement transmission mechanism 72 first fluid pressure circuit mechanism 76 second fluid pressure circuit mechanism 202 Pressure fluid control system 204 First fluid supply control system 206 Second fluid supply control system 208 Pressure fluid supply source 217 First pressure reducing valve 222 First flow path switching valve 236 Second pressure reducing valve 238 Third pressure reducing valve 240 Pressure switching valve 248 2nd channel switching valve

Claims (5)

A chuck body that is rotationally driven integrally with the spindle, a plurality of first claw members that are disposed at intervals in the circumferential direction and are supported by the chuck body so as to be movable in the radial direction, and the plurality of first claw members A thin workpiece chucking method for chucking a thin workpiece using a chuck device provided with a plurality of second claw members that are disposed between and supported by the chuck main body so as to be movable in the radial direction. ,
A first cylinder mechanism for moving the plurality of first claw members in the radial direction; a second cylinder mechanism for moving the plurality of second claw members in the radial direction; A first fluid pressure circuit mechanism for supplying a pressure fluid of one pressure and a second fluid pressure circuit mechanism for supplying a pressure fluid of a second pressure lower than the first pressure;
When holding a thin workpiece, the pressure fluid from the second fluid pressure circuit mechanism is supplied to the second cylinder mechanism, and the plurality of second claw members are moved inward in the radial direction by the second cylinder mechanism. The thin workpiece is positioned, and then the pressure fluid from the first fluid pressure circuit mechanism is supplied to the first cylinder mechanism in a state where the pressure fluid from the second fluid pressure circuit mechanism is supplied to the second cylinder mechanism. And the plurality of first claw members are moved radially inward by the first cylinder mechanism to sandwich and hold the thin workpiece, and then the pressure fluid from the first fluid pressure circuit mechanism is supplied to the first fluid mechanism. Supplying to the two-cylinder mechanism, and causing the pressure fluid from the first fluid pressure circuit mechanism to act on the plurality of second claw members and the plurality of first claw members to sandwich and hold the thin workpiece. Chucking method of thin-walled work to butterflies. The holding and holding surfaces of the plurality of first claw members extend in an arc shape corresponding to the outer shape of the thin workpiece, and a holding pressure relief recess extending in the arc-shaped direction is part of the holding and holding surfaces. The method for chucking a thin-walled work according to claim 1 , wherein The positioning surfaces of the plurality of second claw members extend in an arc shape corresponding to the outer shape of the thin workpiece, and a positioning pressure relief recess extending in the arc direction is provided in a part of the positioning surfaces. chucking method of the thin workpiece according to claim 1, characterized in that are. A chuck body that is rotationally driven integrally with the spindle, a plurality of first claw members that are disposed at intervals in the circumferential direction and are supported by the chuck body so as to be movable in the radial direction, and the plurality of first claw members A thin workpiece chucking method for chucking a thin workpiece using a chuck device provided with a plurality of second claw members that are disposed between and supported by the chuck main body so as to be movable in the radial direction. ,
A first cylinder mechanism for moving the plurality of first claw members in the radial direction is provided, and a second cylinder mechanism for moving the plurality of second claw members in the radial direction is provided, and the first cylinder mechanism is provided. A pressure fluid of a first pressure is supplied to the cylinder mechanism, and a pressure fluid of the first pressure and a pressure fluid of a second pressure lower than the first pressure are supplied to the second cylinder mechanism. Configure
When holding a thin-walled work, pressure fluid of the second pressure is supplied to the second cylinder mechanism, and the plurality of second claw members are moved inward in the radial direction by the second cylinder mechanism so that the thin-walled work Is positioned, and then, while the pressure fluid of the second pressure is supplied to the second cylinder mechanism, the pressure fluid of the first pressure is supplied to the first cylinder mechanism, and the plurality of pressure fluids are supplied by the first cylinder mechanism. The first claw member is moved inward in the radial direction to sandwich and hold the thin workpiece, and then the first pressure fluid is supplied to the second cylinder mechanism, and the first pressure fluid is supplied to the second cylinder mechanism. A thin workpiece chucking method, wherein the thin workpiece is clamped and held by acting on the plurality of second claw members and the plurality of first claw members. A chuck body that is rotationally driven integrally with a spindle, a plurality of first claw members disposed circumferentially at intervals and radially supported movably in the radial direction, the plurality of first claw members A thin workpiece chucking method for chucking a thin workpiece using a chuck device provided with a plurality of second claw members that are disposed between and supported by the chuck main body so as to be movable in the radial direction. ,
A first cylinder mechanism for moving the plurality of first claw members in the radial direction to hold the thin workpiece is provided, and the plurality of second claw members are moved in the radial direction to move the thin workpiece. Provide a second cylinder mechanism for holding
Further, a first fluid pressure circuit mechanism is provided in association with the first cylinder mechanism, and a first fluid is supplied to the plurality of first claw members via the first cylinder mechanism by pressure fluid from the first fluid pressure circuit mechanism. Further, a second fluid pressure circuit mechanism is provided in association with the second cylinder mechanism, and a pressure fluid from the second fluid pressure circuit mechanism is interposed through the second cylinder mechanism. The first holding and holding force and a second holding pressure smaller than the first holding pressure are applied to the plurality of second claw members.
When holding a thin workpiece, the second cylinder mechanism moves the plurality of second claw members inward in the radial direction to position the thin workpiece with the second clamping holding force, and then the thin workpiece. In the state where the second holding force is positioned and held, the first cylinder mechanism moves the plurality of first claw members inward in the radial direction to hold the thin workpiece with the first holding force. And holding the thin workpiece with the first clamping holding force by causing the second cylinder mechanism to act on the plurality of second claw members in a state where the thin workpiece is clamped and held with the first clamping holding force. A chucking method for a thin-walled work characterized by holding and holding.

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