JP6518762B2 - Fluid pressure clamp device - Google Patents

Description

  The present invention relates to a hydraulic clamp device, and more particularly to a hydraulic clamp device suitable for clamping small parts.

  When polishing, etc., the optical lens is attached to the recess of the recess plate with an adhesive as an apparatus for clamping the optical lens, and the optical lens is closely attached to the reference surface of the recess plate by vacuuming from the inside of the recess. A thing is known (for example, patent document 1).

  As a device for clamping the inner contour of the object to be clamped, an outward claw is formed at the tip of each arm of the collet chuck, and the rubber sleeve disposed inside the collet chuck is expanded and deformed by increasing the internal pressure of the fluid receiving chamber. It is known that the inner contour of the portion to be clamped is clamped by the claws by expanding the diameter of the collet chuck by this expansion deformation (e.g., Patent Document 2).

  As a fluid pressure type clamping device, a working fluid chamber is formed in the shaft-like portion with a shell wall defined on the outer peripheral side, and the working fluid filled in the working fluid chamber is pressurized to expand the shell wall It is known to expand and clamp the inner contour of the object to be clamped disposed on the outer periphery of the shell wall (e.g., Patent Document 3).

  As another fluid pressure type clamp device, a working fluid chamber is formed in the cylindrical portion with an inner peripheral side being defined by a shell wall, and the shell fluid is contracted by pressurizing the working fluid filled in the working fluid chamber. It is known to radially expand and clamp the outer contour of the object to be clamped disposed on the inner periphery of the shell wall (e.g., Patent Document 4).

Unexamined-Japanese-Patent No. 2000-79547 Unexamined-Japanese-Patent No. 2002-36162 Patent No. 4344573 Japanese Utility Model Publication No. 58-21605

  Although the clamp apparatus as shown in Patent Document 1 is suitable for clamping a clamp of a small part such as an optical lens with high positional accuracy, since it involves the use of an adhesive, the clamp is efficiently repeated repeatedly.・ It is difficult to unclamp.

  Although the clamp apparatus as shown in Patent Document 2 is suitable for clamping the inner contour of the object having a short axial length, a mechanism including a collet chuck and a rubber sleeve for operating the collet chuck is required. The structure is complicated.

  The clamping device as shown in Patent Document 3 is suitable for clamping the inner contour of a cylinder having a relatively long axial length, but clamping the inner contour of the object to be clamped having a short axial length. Not suitable for

  The clamping device as shown in Patent Document 4 is suitable for clamping the outer contour of a shaft having a relatively long axial length, but clamping the outer contour of a clamped object having a short axial length. Not suitable for

  The problem to be solved by the present invention is to make it possible to properly clamp a workpiece having a short axial length with a simple structure.

  A fluid pressure type clamp device according to the present invention includes a shaft-like portion (16) and a clamp body (12) having a working fluid chamber (22, 60) formed in the shaft-like portion (16); 60) and the pressurizing means (30, 32, 42) for pressurizing the working fluid filled therein, wherein the working fluid chamber (22, 60) is the shaft portion (16). The clamp body (12) extends in the axial direction in the vicinity of the outer periphery of the outer peripheral wall (24), and the clamp body (12) defines an outer peripheral wall (24 of the working fluid chamber (22, 60)). 52) and the tip wall (26, 54) defining the axial tip of the working fluid chamber (22, 60), and the axial direction of the outer peripheral wall (24, 52) from the tip wall (26, 54) Extending on the extension line of the Cantilever-like extending walls (28, 56) displaced radially inward of the shaft-like portion (16) with the tip wall (26, 54) as a fulcrum by elastic deformation of the outer circumferential wall (24, 52) And clamps the object to be clamped (Wa, Wb) by the extending wall (28, 56).

  According to this configuration, the elastic deformation of the outer peripheral wall (24, 52) of the working fluid chamber (22, 60) due to the pressurization of the working fluid causes the extending wall (28, 56) to move in the radial direction of the shaft portion (16) Since the object to be clamped (Wa, Wb) is clamped by the extending walls (28, 56), the object to be clamped (Wa, Wb) can be clamped with a simple structure. The extension wall (28, 56) is a cantilevered beam which is displaced radially inward of the shaft-like portion (16) with the tip wall (26, 54) as a fulcrum, Wa, Wb) can also be properly clamped.

  A fluid pressure type clamp device according to the present invention includes a tubular body (77) and a clamp body (72, 112) having a working fluid chamber (82, 118) formed in the tubular portion (77); A fluid pressure type clamping device having pressurizing means (90, 92, 102, 126, 128, 134) for pressurizing the working fluid filled in (82, 118), said working fluid chamber (82, 118) Extends in the axial direction in the vicinity of the inner periphery of the cylindrical portion (77) to the vicinity of the tip of the cylindrical portion (77), and the clamp body defines an inner peripheral wall defining the inner periphery of the working fluid chamber (84, 120) and a tip wall (86, 122) defining an axial tip of the working fluid chamber (82, 118), and the tip wall (86, 122) of the inner circumferential wall (84, 120) Extend on an axial extension A cantilever beam which is displaced radially outward of the cylindrical portion (77) by supporting the tip wall (86, 122) by elastic deformation of the inner peripheral wall (84, 120) by pressurization of the working fluid. And extending walls (88, 124) for clamping the object to be clamped (Wc, Wd, We) by the extending walls (88, 124).

  According to this configuration, the elastic deformation of the inner peripheral wall (84, 120) of the working fluid chamber (82, 118) due to the pressurization of the working fluid causes the extending wall (88, 124) to move in the radial direction of the cylindrical portion (77). Clamps the object to be clamped (Wc, Wd, We) by the extending wall (88, 124) by displacing it, so that the object to be clamped (Wc, Wd, We) can be clamped with a simple structure. it can. The extending wall (88, 124) is a cantilevered beam which is displaced radially outward of the cylindrical portion (77) with the tip wall (86, 122) as a fulcrum, so Wc, Wd, We) can also be properly clamped.

  The hydraulic clamp device according to the present invention preferably comprises the outer peripheral wall (24, 52) or the inner peripheral wall (84, 120), the tip wall (26, 54, 86, 122) and the extension wall (28, 56, 88, 124) are separate members (20, 50, 80, 116) from the main members (18, 78, 114) constituting most of the shaft-like portion (16) or the cylindrical portion (77) Are integrated with each other.

  According to this configuration, the working fluid chamber (22, 60, 82, 118) can be easily defined by the main member (18, 78, 114) and the separate members (20, 50, 80, 116). 24, 52) or the inner peripheral wall (84, 120), the tip wall (26, 54, 86, 122) and the extending wall (28, 56, 88, 124) are separate members (20, 50, 80, 116) And the distal end wall (26, 54, 86, 122) is elastically deformed by the elastic deformation of the outer peripheral wall (24, 52) or the inner peripheral wall (84, 120). It is ensured that displacement is performed radially inward of the shaft-like portion (16) or radially outward of the cylindrical portion (77) with the point 86, 122) as a fulcrum.

  In the fluid pressure type clamp device according to the present invention, preferably, the tip end wall (26, 54, 86, 122) extends in a direction orthogonal to the axial direction of the shaft portion (16) or the cylindrical portion (77). There is a tip surface (26A, 86A, 122A) for positioning the object to be clamped (Wa, Wb, Wc, Wd, We) in the axial direction.

  According to this configuration, axial positioning of the object to be clamped (Wa, Wb, Wc, We) is performed without the need for an additional structure.

  In the fluid pressure type clamp device according to the present invention, preferably, the outer peripheral wall (24) or the inner peripheral wall (84, 120) and the extension wall (28, 88, 124) have an annular shape with the same cross section.

  According to this configuration, it is possible to appropriately clamp the to-be-clamped object (Wa, Wc, We) having a circular or annular cross-sectional shape.

  In the fluid pressure type clamp device according to the present invention, preferably, the outer peripheral wall (52) or the inner peripheral wall (84) and the extending wall (56, 88) have a polygonal ring of the same cross section.

  According to this configuration, it is possible to properly clamp the object to be clamped (Wb, Wd) having a polygonal cross-sectional shape.

  In the fluid pressure type clamp device according to the present invention, preferably, the shaft portion (16) or the tubular portion (77) is polygonal, and the working fluid chamber (60, 82) and the outer peripheral wall (52) or The inner peripheral wall (84) and the extending wall (56, 88) are individually formed corresponding to each side of the polygonal shape.

  According to this configuration, it is possible to properly clamp the object to be clamped (Wb, Wd) having a polygonal cross-sectional shape.

  In the fluid pressure type clamp device according to the present invention, preferably, the tip wall (26, 86) is formed with a recess (27, 87) for reducing the thickness of the tip wall (26, 86).

  According to this configuration, the extending wall (28, 88) having the tip wall (26, 86) as the fulcrum is easily displaced in the radial direction of the shaft portion (16) or the cylindrical portion (77).

  According to the fluid pressure type clamp device according to the present invention, the extending wall is displaced in the radial direction of the shaft-like portion or the tubular portion by the elastic deformation of the outer circumferential wall or the inner circumferential wall of the working fluid chamber Since the object to be clamped is clamped by the extension wall, the object to be clamped can be clamped with a simple structure, and the extension wall is displaced in the radial direction of the cylindrical portion with the tip wall as a fulcrum Because it has a cantilever shape, it is possible to clamp an object having a short axial length properly.

The perspective view which shows Embodiment 1 of the hydraulic clamp apparatus by this invention Sectional drawing of the hydraulic clamp apparatus by Embodiment 1 (equivalent to sectional drawing along line II-II of FIG. 1) An enlarged cross-sectional view of the main part of the fluid pressure type clamp device according to the first embodiment Explanatory drawing which shows the working principle of the hydraulic type clamp apparatus by Embodiment 1. An enlarged cross-sectional view of an essential part showing a modification of the hydraulic pressure clamp device according to the first embodiment The perspective view which shows Embodiment 2 of the hydraulic clamp apparatus by this invention An enlarged cross-sectional view of the hydraulic clamping device according to Embodiment 1 (corresponding to a cross-sectional view along line VII-VII in FIG. 6) The perspective view which shows Embodiment 3 of the hydraulic clamp apparatus by this invention Sectional drawing of the hydraulic clamp apparatus by Embodiment 3 (equivalent to sectional drawing along line IX-IX of FIG. 8) An enlarged cross-sectional view of the main part of the fluid pressure type clamp device according to the third embodiment Explanatory drawing which shows the working principle of the hydraulic type clamp apparatus by Embodiment 3 An enlarged cross-sectional view of the main parts showing a modification of the hydraulic pressure clamp device according to the third embodiment The perspective view which shows Embodiment 4 of the hydraulic clamp apparatus by this invention The expanded longitudinal section showing Embodiment 5 of the fluid pressure type clamp device by the present invention Sectional view along line XV-XV of FIG. An enlarged cross-sectional view of an essential part showing another embodiment of the fluid pressure type clamp device according to the present invention An enlarged cross-sectional view of an essential part showing another embodiment of the fluid pressure type clamp device according to the present invention

  Embodiment 1 of the fluid pressure type clamp device according to the present invention will be described with reference to FIGS. 1 to 3.

  The hydraulic clamp device 10 has a clamp body 12. The clamp body 12 comprises a main member 18 constituting a major portion of a shaft-like portion 16 of a circular cross section extending from the disk-like mounting flange portion 14 and the mounting flange portion 14 to one side in the axial direction; And a sleeve member 20 fixed by brazing or the like to the outer periphery on the distal end side of the member 18. The main member 18 and the sleeve member 20 are made of a metal material such as stainless steel or a hard synthetic resin, ceramic or the like. The mounting flange portion 14 and the shaft portion 16 are concentric with each other. The clamp body 12 is attached to the spindle or the like of the machine tool by the attachment flange portion 14.

  The main member 18 has a small diameter portion 18A on the tip end side and cooperates with the sleeve member 20 at the portion of the small diameter portion 18A to extend the vicinity of the outer periphery of the shaft 16 to the vicinity of the tip of the shaft 16 in the axial direction. The working fluid chamber 22 has an annular cross-sectional shape.

  The sleeve member 20 has a thin cylindrical outer peripheral wall 24 extending in the axial direction of the main member 18 to define the outer periphery of the working fluid chamber 22, and a direction orthogonal to the outer peripheral wall 24 (radial direction of the main member 18) And an inward annular flange-like tip wall 26 defining the axial tip of the working fluid chamber 22, and an axial extension of the outer circumferential wall 24 from the tip wall 26 (axial direction of the main member 18) It has the cylindrical extending wall 28 by the cantilever which extended in the line integrally. The tip of the working fluid chamber 22 in the axial direction is the end on the same side as the tip of the axial portion 16 in the axial direction (the tip on the small diameter portion 18A side).

  The extending wall 28 is concentric with the outer peripheral wall 24 and has an axial length (axial length) shorter than that of the outer peripheral wall 24 and a radial thickness substantially equal to the radial thickness of the outer peripheral wall 24 It has an annular shape with the same cross section as the outer peripheral wall 24. The extending wall 28 has the same cylindrical shape as the outer contour of the object to be clamped Wa of a circular cross section, receives the object to be clamped Wa inside, and surrounds the outer periphery (entire circumference) of the object to be clamped Wa. The inner diameter of the extension wall 28 is set to be equal to or slightly larger than the outer diameter of the object to be clamped Wa in the natural state.

  The clamped object Wa may have a short axial length such as an optical lens, and the axial dimension (extension length) of the extending wall 28 is smaller than the axial dimension of the clamped object Wa. When processing the end face of the object to be clamped Wa, the dimensional difference in the axial direction between the extending wall 28 and the object to be clamped Wa is at least larger than the end surface processing allowance, and the tool of the end surface processing interferes with the extending wall 28 Not set to a value.

  The distal end wall 26 extends in a direction orthogonal to the axial direction of the axial portion 16, that is, radially inward of the axial portion 16 from the outer peripheral wall 24 and the extending wall 28, and forms an annular flange shape. It has an end surface 26B that is flush with the 18 end surfaces 18B. In other words, the distal end wall 26 forms a connection between the outer peripheral wall 24 and the extending wall 28 and extends in the radial direction of the shaft-like portion 16. Compared with the outer wall 24 and the extension wall 28 in the same direction, the main wall 18 has a thick part in the radial direction and a high rigidity compared to the outer wall 24 and the extension wall 28. On the other hand, there is a fixed point fixed firmly.

  The tip end surfaces 18B and 26A are positioned in the axial direction of the to-be-clamped object Wa by inserting the to-be-clamped object Wa to the inside of the extension wall 28 until abutting on them, and the to-be-clamped object Wa falls To stop. As a result, the object to be clamped Wa is disposed concentrically with the shaft-like portion 16 with straightness.

  A piston chamber 30 is formed in the clamp body 12 concentrically with the shaft-like portion 16. A piston 32 is axially movably fitted to one end of the piston chamber 30. The other end side of the piston chamber 30 is in communication with the working fluid chamber 22 by communication holes 34 and 36 formed in the clamp body 12. The working fluid chamber 22, the piston chamber 30, and the communication holes 34, 36 define one sealed space, and the sealed space is filled with hydraulic oil as an incompressible fluid.

  A cylindrical portion 38 is formed so as to project concentrically with the mounting flange portion 14 on the side opposite to the shaft portion 16 of the mounting flange portion 14. In the cylindrical portion 38, a screw hole 40 communicating with the arrangement portion of the piston 32 is formed on an extension of the piston chamber 30 in the axial direction. The screw hole 40 is opened at the end surface of the cylindrical portion 38 (the end surface opposite to the end surface 18 B of the main member 18). An external thread portion 44 of the operating screw member 42 inserted from the side of the open end is engaged with the screw hole 40 in a screw manner. A steel ball 48 is disposed between the male screw 44 and the piston 32 so as to be sandwiched therebetween. The actuating screw member 42 has a hexagonal column 46 projecting outward from the open end of the screw hole 40 integrally with the male screw 44. In this manner, a pressurizing means for pressurizing the hydraulic fluid of the hydraulic fluid chamber 22 is configured in the clamp body 12.

  The actuating screw member 42 is screwed to the screwing side by a tool such as a hexagonal spanner engaged with the hexagonal column 46, and when screwed to the right as viewed in FIG. 2, the piston 32 axially moves to the right through the steel ball 48. The pressure of the hydraulic fluid which is moved and sealed in the working fluid chamber 22, the piston chamber 30, and the communication holes 34, 36 rises. The pressure increase of the hydraulic oil causes the outer peripheral wall 24 to elastically deform so as to expand in the radial direction of the axial portion 16.

  When the outer peripheral wall 24 is elastically deformed to expand in the radial direction, as shown in FIG. 4, the extending wall 28 is a fixing point of the connecting member of the outer peripheral wall 24 and the extending wall 28 to the main member 18. The tip end wall 26 is displaced inward in the radial direction of the shaft-like portion 16 like a fulcrum of a forceps. By this displacement, the extension wall 28 is pressed against the outer contour of the object to be clamped Wa, and clamping of the object to be clamped Wa is performed.

  As a result, since the cantilevered extended wall 28 clamps the object to be clamped Wa with the tip of the forceps, even if the object to be clamped Wa has a short axial length like an optical lens, It can be clamped securely.

  The extending wall 28 has the same cylindrical shape as the outer contour shape of the object to be clamped Wa and has an annular shape with the same cross section as the outer peripheral wall 24, so that elastic deformation of the outer peripheral wall 24 extends over the entire circumferential direction. The uniform radial inward displacement allows the clamping of the outer contour of the object to be clamped Wa by the extending wall 28 to be performed with high concentricity with high accuracy to the shaft-like portion 16.

  The dimension in the axial direction of the extension wall 28 is smaller than the dimension in the axial direction of the object to be clamped Wa, and the difference in dimension in the axial direction between the extension wall 28 and the object to be clamped Wa is larger than the end face machining allowance of the object to be clamped Wa Since the dimension difference can be set to a value by which the tool for end surface processing does not interfere with the extending wall 28 by setting the axial length of the extending wall 28, the axial length of which the outer contour is clamped by the hydraulic clamping device 10 is The end face processing of the short object to be clamped Wa can be performed without any problem.

  Further, by inserting the object to be clamped Wa into the inside of the extension wall 28 until the object to be clamped abuts on the end surfaces 18B and 26A, the axial direction of the object to be clamped Wa is positioned and the object to be clamped Wa falls Be blocked. As a result, the object to be clamped Wa is clamped concentrically to the shaft portion 16 with high straightness.

  When the actuating screw member 42 is turned to the slack side and screwed to the left as viewed in FIG. 2, the piston 32 axially moves to the left as pushed by the pressure of the hydraulic fluid, and the working fluid chamber 22 and the piston chamber 30. And the pressure of the hydraulic oil sealed in the communication holes 34, 36 drops. When the pressure of the hydraulic oil returns to the original state (approximately atmospheric pressure), the elastic deformation of the outer peripheral wall 24 disappears, and the extension wall 28 returns to the original state.

  When the extension wall 28 returns to the original state, the extension wall 28 is not pressed against the outer contour of the object to be clamped Wa, and the clamp of the object to be clamped Wa is released.

  As described above, the fluid pressure type clamping device 10 can clamp and unclamp the object to be clamped Wa having a short axial length with a simple structure without requiring many components.

  As a modified embodiment of the first embodiment, as shown in FIG. 5, the corner connecting the tip wall 26 and the outer peripheral wall 24 and the corner connecting the tip wall 26 and the extending wall 28. An annular recess 27 may be formed to reduce the thickness of the tip wall 26.

  When the recess 27 is provided, the extension wall 28 can be easily displaced inward in the radial direction of the shaft-like portion 16 like the tip wall 26 as a fulcrum of the forceps, and the internal pressure rises in the working fluid chamber 22 Even if there is little, the clamping of the object to be clamped Wa by the extending wall 28 is performed with the required clamping force.

  Next, a second embodiment of the fluid pressure type clamp device according to the present invention will be described with reference to FIG. 6 and FIG. In FIGS. 6 and 7, parts corresponding to FIGS. 1 to 3 are given the same reference numerals as the reference numerals attached to FIGS. 1 to 3, and the description thereof will be omitted.

  The hydraulic clamping device 10 of the second embodiment is intended for clamping a triangular clamp object Wb having a short axial length such as a tool tip, and the tip end side of the main member 18 has a triangular cross section 18C having a triangular cross section. It has become.

  A shallow concave portion 18D having a rectangular planar shape is formed on a rectangular planar portion of each side of the triangular prism portion 18C. A plate-like member 50 is fixed to the flat portion of each side of the triangular column portion 18C by brazing or the like.

  Each of the three plate members 50 covers the opening of the recess 18 D to define a rectangular flat outer wall (outer wall) 52 which defines the outer periphery of the working fluid chamber 60, and a direction perpendicular to the outer wall 52 (main member 18 A rectangular strip-shaped tip wall 54 extending in the radial direction of the outer circumferential wall 52 to define an axial tip of the working fluid chamber 22 and an axial extension (axial direction of the main member 18) of the outer circumferential wall 52 from the tip wall 54 It integrally has a rectangular piece-like extending wall 56 of a cantilever beam extending in a line. Thus, the working fluid chamber 60, the outer peripheral wall 52, and the extending wall 56 are individually formed corresponding to each side of the triangle. Also in this embodiment, the end in the axial direction of the working fluid chamber 60 is the end on the same side as the end in the axial direction of the shaft-like portion 16 (the end on the side of the triangular prism portion 18C).

  The three extending walls 56 have an axial length (axial length) shorter than the axial length of the outer peripheral wall 52 and have a plate thickness substantially equal to the plate thickness of the outer peripheral wall 52, and cooperate with one another The workpiece Wb has a triangular shape equivalent to the outer contour of the workpiece Wb, receives the workpiece Wb inside, and is joined to each side of the workpiece Wb. In the natural state, the triangular shape of the three extending walls 56 is set to a size equal to or slightly larger than the outer size of the object to be clamped Wb.

  The axial dimension (extension length) of the extension wall 56 is smaller than the axial dimension of the object to be clamped Wb. When processing the end face of the workpiece Wb, the axial dimension difference between the extension wall 56 and the workpiece Wb is at least larger than the end face machining allowance, and the tool for the end face processing interferes with the extension wall 56 Not set to a value.

  The three working fluid chambers 60 are in communication with the piston chamber 30 by the communication holes 34 and 36. The pressurizing means for pressurizing the hydraulic fluid of the hydraulic fluid chamber 60 including the piston chamber 30 is configured in the clamp body 12 as in the first embodiment.

  When the pressure of the hydraulic fluid in the hydraulic fluid chamber 60 is increased by the screwing of the operating screw member 42, the outer peripheral walls 52 are elastically deformed so as to expand in the radial direction of the axial portion 16. When the outer peripheral wall 52 is elastically deformed so as to expand in the radial direction, as in the first embodiment, as shown in FIG. 4, each extending wall 56 is connected to the outer peripheral wall 52 and the extending wall 56. The distal end wall 54 which is a fixing point to the main member 18 of the body is displaced radially inward of the shaft-like portion 16 like a fulcrum of a forceps. By this displacement, each extended wall 56 is pressed against the outer contour of the object to be clamped Wb, and clamping of the object to be clamped Wb is performed.

  As a result, since the cantilever-shaped extended wall 56 clamps the object Wb to be clamped at the tip of the forceps, even if the object Wb has a short axial length like an optical lens, It can be clamped securely.

  Since the three plate-like members 50 and the working fluid chamber 60 have the same structure, the three extending walls 56 are uniformly radially inwardly displaced from one another. Clamping of the outer contour of Wb takes place with high concentricity to the shaft 16 with high accuracy.

  The dimension in the axial direction of the extension wall 56 is smaller than the dimension in the axial direction of the object to be clamped Wb, and the difference in dimension in the axial direction between the extension wall 56 and the object to be clamped Wb is larger than the end face machining allowance of the object to be clamped Wb, Since the dimension difference can be set to a value by which the tool for end surface processing does not interfere with the extending wall 56 by setting the axial length of the extending wall 56, the outer contour is clamped by the hydraulic clamping device 10 as in the first embodiment. The end face processing of the object Wb to be clamped having a short axial length can be performed without any problem.

  Further, by inserting the object to be clamped Wb inside the extension wall 56 until the object to be clamped W abuts on the end surface of the end wall 54 and the end surface of the triangular column 18C, positioning of the object to be clamped Wb in the axial direction is performed. The object to be clamped Wb is prevented from falling. Thereby, the object to be clamped Wb is clamped concentrically with high rigidity to the shaft-like portion 16.

  When the actuating screw member 42 is turned to the slack side, the pressure of the hydraulic fluid in the hydraulic fluid chamber 60 drops, and when the pressure of the hydraulic fluid returns to the original state (approximately atmospheric pressure), the elastic deformation of the outer peripheral wall 52 The extended wall 56 returns to its original state. When the extending wall 56 returns to the original state, the extending wall 56 is released from being pressed against the outer contour of the object to be clamped Wb, and the clamping of the object to be clamped Wb is released.

  As described above, the fluid pressure type clamp device 10 of the second embodiment does not require many components as in the first embodiment, and appropriately clamps the object Wb having a short axial length with a simple structure. It can be unclamped.

  A third embodiment of the hydraulic clamping device according to the present invention will be described with reference to FIGS.

  The hydraulic clamp device 70 has a clamp body 72. The clamp main body 72 includes a main member 78 which constitutes most of a shaft-like portion 76 of a circular cross section extending from the disk-like mounting flange portion 74 and the mounting flange portion 74 to one side in the axial direction; And a thin-walled sleeve member 80 fixed by brazing or the like to the inner periphery of a tubular portion 77 formed in an annular cross-sectional shape formed on the distal end side of the annular portion 76. The main member 78 and the sleeve member 80 are made of a metal material such as stainless steel or a hard synthetic resin, ceramic or the like. The mounting flange 74, the shaft 76 and the cylindrical portion 77 are concentric with each other. The clamp body 72 is attached to the main shaft or the like of the machine tool by the attachment flange portion 74.

  The cylindrical portion 77 cooperates with the sleeve member 80 to constitute a working fluid chamber 82 having an annular cross-sectional shape extending in the vicinity of the inner periphery in the axial direction to the vicinity of the tip of the cylindrical portion 77.

  The sleeve member 80 extends in the axial direction of the main member 78 to define a cylindrical inner peripheral wall 84 defining the inner periphery of the working fluid chamber 82, and in a direction orthogonal to the inner peripheral wall 84 (radial direction of the main member 78) An outwardly directed annular flange-shaped tip wall 86 which extends to define the axial tip of the working fluid chamber 82, and an extension of the axial direction (the axial direction of the main member 78) of the inner circumferential wall 84 from the tip wall 86 And a cylindrical extending wall 88 which is a cantilever beam extended to the lower end. The tip of the working fluid chamber 82 in the axial direction is the end on the same side as the tip of the axial portion 76 in the axial direction (tip at the side of the cylindrical portion 77).

  The extension wall 88 is concentric with the inner circumferential wall 84, and the axial length (axial length) is shorter than the axial length of the inner circumferential wall 84, and the radial thickness substantially equal to the radial thickness of the inner circumferential wall 84 It has an annular shape with the same cross section as the inner circumferential wall 84. The extension wall 88 has the same cylindrical shape as the inner contour of the to-be-clamped object Wc, receives the to-be-clamped object Wc on the outer side, and encloses the inner periphery (full circumference) of the to-be-clamped object Wc. The outer diameter of the extending wall 88 is set to be equal to or slightly smaller than the inner diameter of the object to be clamped Wc in a natural state.

  The object to be clamped Wc has a short axial length, and the axial dimension (extension length) of the extending wall 88 is smaller than the axial direction of the object to be clamped Wc. When processing the end face of the object to be clamped Wc, the axial dimension difference between the extending wall 88 and the object to be clamped Wc is at least larger than the end surface processing allowance, and the tool of the end surface processing interferes with the extending wall 88 Not set to a value.

  The end wall 86 extends in a direction orthogonal to the axial direction of the shaft 76, that is, radially outward of the shaft 76 from the inner circumferential wall 84 and the extension wall 88, and forms an annular flange shape. The front end surface 78A is flush with the front end surface 78A. In other words, the end wall 86 forms a connection between the inner circumferential wall 84 and the extension wall 88 and extends in the radial direction of the shaft-like portion 76. Compared with the inner circumferential wall 84 and the extension wall 88 in the same direction, the thickness of the radial direction is larger than that of the inner circumferential wall 84 and the extension wall 88, and the connecting portion between the inner circumferential wall 84 and the extension wall 88 is used as the main member 78. On the other hand, there is a fixed point fixed firmly.

  The tip end surfaces 78A and 86A are positioned on the axial direction of the object to be clamped Wc by inserting the object to be clamped Wc to the outside of the extension wall 88 until they abut on these, and the object to be clamped Wc falls To stop. Thus, the object to be clamped Wc is disposed concentrically with the shaft 76 with straightness.

  A piston chamber 90 is formed in the main member 78 concentrically with the shaft 76. A piston 92 is axially movably fitted to one end of the piston chamber 90. The other end of the piston chamber 90 is in communication with the working fluid chamber 82 through communication holes 94 and 96 formed in the main member 78. The working fluid chamber 82, the piston chamber 90, and the communication holes 94 and 96 define one sealed space, and the sealed space is filled and sealed with hydraulic fluid as an incompressible fluid.

  A cylindrical portion 98 protrudes concentrically with the mounting flange portion 74 on the opposite side to the shaft portion 76 of the mounting flange portion 74. In the cylindrical portion 98, a screw hole 100 communicating with the arrangement portion of the piston 92 is formed on an extension of the piston chamber 90 in the axial direction. The screw hole 100 is opened at the end surface of the cylindrical portion 98 (the end surface opposite to the end surface 78A of the main member 78). The male screw portion 104 of the operating screw member 102 inserted from the side of the open end is screwed into the screw hole 100. A steel ball 108 is disposed between the male screw portion 104 and the piston 92 so as to be sandwiched therebetween. The actuating screw member 102 has a hexagonal column 106 projecting outward from the open end of the screw hole 100 integrally with the male screw 104. Thus, the clamp body 72 is configured with pressurizing means for pressurizing the hydraulic fluid of the hydraulic fluid chamber 82.

  The operating screw member 102 is screwed to the screwing side by a tool such as a hexagonal spanner engaged with the hexagonal column portion 106, and when screwed to the right as viewed in FIG. 9, the piston 92 axially moves to the right through the steel ball 108. The pressure of the hydraulic fluid which is moved and sealed in the working fluid chamber 82, the piston chamber 90 and the communication holes 94, 96 increases. The pressure rise of the hydraulic oil causes the inner peripheral wall 84 to elastically deform so as to expand in the diameter-decreasing direction of the shaft-like portion 76.

  When the inner peripheral wall 84 is elastically deformed so as to expand in the diameter reducing direction, as shown in FIG. 11, the extending wall 88 is a fixing point of the connecting member of the inner peripheral wall 84 and the extending wall 88 to the main member 78. Is displaced outward in the radial direction of the shaft-like portion 76 as a fulcrum of the forceps. By this displacement, the extension wall 88 is pressed against the circular inner contour of the object to be clamped Wc, and clamping of the object to be clamped Wc is performed.

  As a result, since the cantilevered extended wall 88 clamps the object to be clamped Wc at the tip of the forceps, even if the object to be clamped Wc has a short axial length, clamping is ensured. Can.

  The extending wall 88 has the same cylindrical shape as the inner contour of the object Wc and has an annular shape with the same cross section as the inner peripheral wall 84, so that the elastic deformation of the inner peripheral wall 84 covers the entire circumferential direction. The uniform radial inward displacement allows the clamping of the outer contour of the object to be clamped Wc by the extending wall 88 to be performed with high concentricity to the shaft 76 with high accuracy.

  The dimension in the axial direction of the extension wall 88 is smaller than the dimension in the axial direction of the object to be clamped Wc, and the difference in dimension in the axial direction between the extension wall 88 and the object to be clamped Wc is larger than the end face machining allowance of the object to be clamped Wc Since the dimension difference can be set to a value by which the tool for end surface processing does not interfere with the extending wall 88 by setting the axial length of the extending wall 88, the axial length of which the outer contour is clamped by the hydraulic clamping device 10 is The end face processing of the short workpiece Wc can be performed without any problem.

  Further, by inserting the object to be clamped Wc to the outside of the extending wall 88 until the object to be clamped Wc comes in contact with the end surfaces 78A and 86A, the axial direction of the object to be clamped Wc is positioned and the object to be clamped Wc falls Be blocked. Thereby, the object to be clamped Wc is clamped concentrically with high rigidity to the shaft-like portion 76.

  When the actuating screw member 102 is turned to the slack side and is screwed to the left as viewed in FIG. 8, the piston 92 is axially moved to the left as it is pushed by the pressure of the hydraulic fluid. And the pressure of the hydraulic oil sealed in the communication holes 94, 96 drops. When the pressure of the hydraulic oil returns to the original state (approximately atmospheric pressure), the elastic deformation of the inner circumferential wall 84 disappears, and the extension wall 88 returns to the original state.

  When the extending wall 88 returns to the original state, the extending wall 88 is not pressed against the inner contour of the object to be clamped Wc, and the clamping of the object to be clamped Wc is released.

  As described above, the fluid pressure type clamp device 70 can clamp and unclamp the object Wc having a short axial length with a simple structure without requiring many components.

  As a modified embodiment of the third embodiment, as shown in FIG. 12, the corner connecting the tip wall 86 and the inner circumferential wall 84 and the corner connecting the tip wall 86 and the extending wall 88 An annular recess 87 may be formed to reduce the thickness of the tip wall 86.

  When the recess 87 is provided, the extending wall 88 can be easily displaced outward in the radial direction of the shaft 76 with the tip wall 86 as the fulcrum of the forceps, and the internal pressure of the working fluid chamber 82 rises. Even if there is little, the clamping of the object to be clamped Wc by the extending wall 88 is performed with the required clamping force.

  Embodiment 4 of the fluid pressure type clamp device according to the present invention will be described with reference to FIG. In FIG. 13, portions corresponding to FIG. 8 are denoted by the same reference numerals as the reference numerals shown in FIG. 8, and the description thereof is omitted.

  In the fourth embodiment, since the inner contour of the object to be clamped Wd is square, the inner cylindrical portion of the cylindrical portion 77 has a rectangular cross-sectional shape, and the working fluid chamber 82 also crosses the square In addition to the surface shape, the inner circumferential wall 84 and the extending wall 88 are formed in a square tube shape.

  Except for the difference in shape, the third embodiment is configured substantially the same. Therefore, the same effects as in the third embodiment can be obtained in the fourth embodiment.

  In the fourth embodiment, the inner circumferential wall 84, the tip wall 86, and the extension wall 88 are integrated with the shaft-like portion 76.

  Embodiment 5 of the fluid pressure type clamp device according to the present invention will be described with reference to FIG. 14 and FIG.

  The hydraulic clamping device 110 has a cylindrically shaped clamping body 112. The clamp main body 112 is a cylindrical portion as a whole, and includes a main member 114 forming a major part of a cylindrical shape, and a sleeve member 116 fixed to the inner periphery of the main member 114 by brazing or the like. . The main member 114 and the sleeve member 116 are made of a metal material such as stainless steel or a hard synthetic resin, ceramic or the like.

  The main member 114 cooperates with the sleeve member 116 to form a working fluid chamber 118 having an annular cross-sectional shape, which extends axially near the inner periphery to the vicinity of the end face of the main member 114.

  The sleeve member 116 has a thin cylindrical inner circumferential wall 120 extending in the axial direction of the main member 114 to define the inner circumference of the working fluid chamber 118, and a direction orthogonal to the inner circumferential wall 120 (a radial direction of the main member 114 And an outward annular flange-like tip wall 122 defining an axial tip of the working fluid chamber 118, and an axial direction of the inner circumferential wall 120 from the tip wall 122 (axial direction of the main member 114) It integrally has a cylindrical extending wall 124 of a cantilever that extends on an extension line. The tip end in the axial direction of the working fluid chamber 118 is the end on the same side as the end face of the main member 114 described above.

  The extension wall 124 is concentric with the inner circumferential wall 120, has an axial length (axial length) shorter than the axial length of the inner circumferential wall 120, and has a radial thickness substantially equal to the radial thickness of the inner circumferential wall 120. And has an annular shape with the same cross section as the inner circumferential wall 120. The extension wall 124 has the same cylindrical shape as the inner contour of the to-be-clamped object We, receives the to-be-clamped item We on the outer side, and surrounds the entire circumference of the to-be-clamped object We. The outer diameter of the extension wall 124 is set to be equal to or slightly smaller than the inner diameter of the object to be clamped We in the natural state.

  The object to be clamped We is short in axial length, and the axial dimension (extension length) of the extension wall 124 is smaller than the axial direction of the object We to clamp. When processing the end face of the object to be clamped We, the dimensional difference in the axial direction between the extension wall 124 and the object to be clamped We is at least larger than the end face machining allowance, and the tool of the end face processing interferes with the extension wall 124 Not set to a value.

  The end wall 122 has a thickness (axial thickness) thicker than the inner circumferential wall 120 and the extension wall 124 and is perpendicular to the axial direction of the main member 114, ie, from the inner circumferential wall 120 and the extension wall 124 The member 114 extends radially outward to form an annular flange shape, and has a distal end surface 122A flush with the distal end surface 114A of the main member 114. In other words, the tip end wall 122 forms a connection between the inner peripheral wall 120 and the extension wall 124, and extends in the radial direction of the main member 114 with a thickness greater than that of the inner peripheral wall 120 and the extension wall 124. Thus, a fixing point is provided which has a higher rigidity than the inner circumferential wall 120 and the extending wall 124 and rigidly fixes the connection portion between the inner circumferential wall 120 and the extending wall 124 to the main member 114. There is.

  The tip end surfaces 114A and 122A allow the clamped object We to be positioned in the axial direction by inserting the clamped object We to the outside of the extension wall 124 until it abuts on these, and the clamped object We may fall. To stop. Thus, the object to be clamped We is disposed concentrically with the clamp body 112 with straightness.

  A piston chamber 126 is formed in the main member 114. A piston 128 is movably fitted to one end side of the piston chamber 126 in the longitudinal direction of the piston chamber 126. The other end of the piston chamber 126 is in communication with the working fluid chamber 118 by a communication hole 130 formed in the main member 114. The working fluid chamber 118, the piston chamber 126, and the communication hole 130 define one sealed space, and the sealed space is filled with hydraulic oil as an incompressible fluid.

  The main member 114 is formed with a working fluid chamber 118 when the working oil is filled, and air vent holes 140 and 142 for venting the piston chamber 126. The air vent holes 140, 142 are closed by the seal screws 144, 146 after the air vent action.

  In the main member 114, a screw hole 132 communicating with the arrangement portion of the piston 128 is formed on an axial extension of the piston chamber 126. The screw hole 132 is open at the outer peripheral surface of the main member 114. The actuating screw member 134 inserted from the side of the open end is in threaded engagement with the screw hole 132. A steel ball 136 is disposed between the actuating screw member 134 and the piston 128 so as to be sandwiched therebetween. In this manner, a pressurizing means for pressurizing the hydraulic fluid of the hydraulic fluid chamber 118 is configured in the clamp body 112.

  The operating screw member 134 is a screw member having a hexagonal hole, and is turned to the screwing side by a tool such as a hexagonal wrench, and when it is screwed upward as viewed in FIG. 15, the piston 128 moves upward via the steel ball 136 The pressure of the hydraulic fluid sealed in the working fluid chamber 118, the piston chamber 126 and the communication hole 130 is increased. The pressure increase of the hydraulic oil causes the inner peripheral wall 120 to elastically deform so as to expand in the diameter reducing direction of the clamp body 112.

  When the inner peripheral wall 120 elastically deforms so as to expand in the diameter reducing direction, as shown in FIG. 11, the extending wall 124 is a fixing point of the connecting member of the inner peripheral wall 120 and the extending wall 124 to the main member 114. Of the clamp body 112 as the fulcrum of the forceps. By this displacement, the extended wall 124 is pressed against the circular inner contour of the object We, and the object We is clamped.

  As a result, since the cantilevered extended wall 124 clamps the object We to be clamped at the tip of the forceps, it is possible to reliably clamp even if the object We is short. Can.

  The extension wall 124 has the same cylindrical shape as the inner contour shape of the object to be clamped We, and has an annular shape with the same cross section as the inner circumferential wall 120, so that the elastic circumferential deformation of the inner circumferential wall 120 Since the inner wall is uniformly displaced radially inward, clamping of the inner contour of the object to be clamped We by the extending wall 124 is performed with high concentricity to the clamp body 112 with high accuracy.

  The dimension in the axial direction of the extension wall 124 is smaller than the dimension in the axial direction of the workpiece We, and the difference in the axial direction between the extension wall 124 and the workpiece We is larger than the end face machining allowance of the workpiece We, Since the dimension difference can be set to a value by which the tool for end surface processing does not interfere with the extending wall 124 by setting the axial length of the extending wall 124, the axial length of which the outer contour is clamped by the hydraulic clamping device 110 is The end face processing of the short workpiece We can be performed without any problem.

  Also, by inserting the object to be clamped We against the tip surfaces 114A and 122A and then inserting it outside the extension wall 124, positioning of the object to be clamped We in the axial direction is performed, and the object to be clamped We falls. Be blocked. As a result, the object to be clamped We is clamped concentrically to the clamp body 112 with high straightness.

  When the actuating screw member 134 is turned to the slack side and screwed to the lower side as viewed in FIG. 15, the piston 128 is moved to the lower side as pushed by the pressure of the hydraulic fluid, and the working fluid chamber 118 and the piston chamber 126 And the pressure of the hydraulic oil sealed in the communication hole 130 drops. When the pressure of the hydraulic oil returns to the original state (approximately atmospheric pressure), the elastic deformation of the inner circumferential wall 120 disappears, and the extension wall 124 returns to the original state.

  When the extension wall 124 returns to the original state, the extension wall 124 is released from being pressed against the inner contour of the object to be clamped We, and the clamp of the object to be clamped We is released.

  As described above, the hydraulic clamping device 110 can clamp and unclamp the short-clamped object We with a simple structure without requiring many components.

  In the first to fifth embodiments described above, the object to be clamped Wa to We is clamped by the increase in internal pressure of the working fluid chamber 22, 60, 82 or 118, and the internal pressure of the working fluid chamber 22, 60, 82 or 118 is increased to atmospheric pressure or higher. The unclamped object Wa to We is performed by returning to the default state near the atmospheric pressure, but with the internal pressure of the working fluid chamber 22, 60, 82 or 118 being at the atmospheric pressure or the default state near atmospheric pressure, the object Wa It is also possible to carry out the clamping of .about.We and unclamp the object to be clamped Wa to We by raising the internal pressure of the working fluid chamber 22, 60, 82 or 118.

  The embodiment shown in FIG. 16 has a configuration similar to that of the first embodiment, and in the default state where the internal pressure of the working fluid chamber 22 is atmospheric pressure or near atmospheric pressure, the outer wall of the extension wall 28 has an annular outer diameter. Since the inner contour of the object to be clamped Wec is clamped on the outer periphery of the extending wall 28 by being larger than the inner diameter of the object to be clamped We cause the extending wall 28 to be displaced radially inward by the internal pressure increase of the working fluid chamber 22 , Unclamp the object to be clamped We.

  In this embodiment, an annular positioning flange 21 may be formed on the outer periphery of the sleeve member 20 to position the workpiece We in the axial direction.

  The embodiment shown in FIG. 17 has a configuration equivalent to that of the third embodiment, and in the default state in which the internal pressure of the working fluid chamber 82 is atmospheric pressure or near atmospheric pressure, the inside diameter of the extension wall 88 is a disk-like clamped The outer contour of the object to be clamped is clamped on the inner periphery of the extending wall 88 by being smaller than the outer diameter of the object Wa, and the extending wall 88 is displaced radially outward by the internal pressure increase of the working fluid chamber 82 Thus, the object to be clamped Wa is unclamped.

  In this embodiment, an annular positioning flange 81 may be formed on the inner periphery of the sleeve member 80 for positioning in the axial direction of the object to be clamped Wa.

  While the present invention has been described above with reference to the preferred embodiments, it is to be understood that the present invention is not limited by such embodiments as can be readily understood by those skilled in the art, and deviates from the spirit of the present invention. It can change suitably in the range which is not.

  In the above embodiment, the outer peripheral wall 24, the tip wall 26, the extending wall 28, the outer peripheral wall 52, the tip wall 54, and the extending wall 56 are the sleeve member 20 or the plate member 50 separate from the main member 18. However, they may be integrated with the main member 18 without using separate parts. In addition, the inner circumferential wall 84, the tip wall 86, the extending wall 88, the inner circumferential wall 120, the tip wall 122, and the extending wall 124 are integrated with the main member 78 or 114 without using other parts such as the sleeve members 80 and 116. May be configured.

  The pressurizing means for pressurizing the hydraulic fluid in the hydraulic fluid chamber 22 may be remote from the clamp body 12 and placed separately. Further, the pressure means may be configured to push the piston 32, the piston rod or the like using an actuator, a cam mechanism or the like.

  Moreover, all the components shown in the above embodiment are not necessarily essential, and it is possible to select them as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 10 Fluid pressure type clamp apparatus 12 Clamp main body 14 Flange part for attachment 16 Axial part 18 Main member 18A Small diameter part 18B Tip surface 18C Triangular pillar part 18D Recess 20 Sleeve member 21 Positioning flange 22 Working fluid chamber 24 Outer peripheral wall 26 Tip wall 26A Tip surface 27 recess 28 extension wall 30 piston chamber 32 piston 34 communication hole 36 communication hole 38 cylindrical portion 40 screw hole 42 operation screw member 44 male screw portion 46 hexagonal column portion 48 steel ball 50 plate member 52 outer peripheral wall 54 tip wall 56 extending Exit wall 60 Working fluid chamber 70 Fluid pressure type clamping device 72 Clamping body 74 Mounting flange 76 Core part 77 Cylindrical part 78 Main member 78A Tip surface 80 Sleeve member 81 Positioning flange 82 Working fluid chamber 84 Inner circumferential wall 86 Tip wall 86A Tip surface 87 Recess 88 Extended wall 9 DESCRIPTION OF SYMBOLS 0 piston chamber 92 piston 94 communicating hole 96 communicating hole 98 cylindrical part 100 screw hole 102 operation screw member 104 male screw part 106 hexagonal column part 108 steel ball 110 hydraulic clamping device 112 clamp main body 114 main member 114 A front end surface 116 sleeve member 118 Working fluid chamber 120 Inner circumferential wall 122 Tip wall 122A Tip face 124 Extension wall 126 Piston chamber 128 Piston 130 Communication hole 132 Screw hole 134 Screw thread member 136 Steel ball 140 Air vent hole 144 Seal screw 146 Seal screw Wa Object to be clamped Wb Clamped Object Wc Object to be clamped Wd Object to be clamped We Object to be clamped

Claims (8)

What is claimed is: 1. A hydraulic clamping device comprising: a clamp body including a shaft portion and having a working fluid chamber formed in the shaft portion; and a pressure means for pressing the working fluid filled in the working fluid chamber,
The working fluid chamber extends in the axial direction in the vicinity of the outer periphery of the shaft portion to the vicinity of the tip of the shaft portion,
The clamp body is
An outer peripheral wall defining an outer periphery of the working fluid chamber, and a tip wall defining an axial tip of the working fluid chamber;
Extending from the tip wall on an extension of the outer circumferential wall in the axial direction, and displacing the tip wall radially inward of the shaft-like portion by elastic deformation of the outer circumferential wall by pressurization of the working fluid With a cantilevered extension wall,
The fluid pressure type clamp device which clamps a thing to be clamped by said extension wall. What is claimed is: 1. A fluid pressure type clamping device comprising: a clamp body including a tubular portion and having a working fluid chamber formed in the tubular portion; and pressing means for pressing the working fluid filled in the working fluid chamber,
The working fluid chamber extends axially in the vicinity of the inner periphery of the cylindrical portion to the vicinity of the tip of the cylindrical portion,
The clamp body is
An inner circumferential wall defining an inner periphery of the working fluid chamber and a tip wall defining an axial tip of the working fluid chamber;
Extending from the tip wall on an extension of the inner circumferential wall in the axial direction of the inner circumferential wall, and displacing the tip wall radially outward of the cylindrical portion by elastic deformation of the inner circumferential wall by pressurization of the working fluid With a cantilevered extension wall,
The fluid pressure type clamp device which clamps a thing to be clamped by said extension wall.   The outer peripheral wall or the inner peripheral wall, the tip end wall, and the extending wall are integrally formed with a shaft-shaped portion that constitutes the major portion of the shaft-shaped portion or the cylindrical portion by a separate member from operation. The fluid pressure type clamp device according to claim 1 or 2.   The tip end wall has a tip end surface extending in a direction orthogonal to the axial direction of the shaft-like portion or the cylindrical portion to position the object to be clamped in the axial direction. A fluid pressure type clamp device according to any one of the preceding claims.   The fluid pressure type clamp device according to any one of claims 1 to 4, wherein the outer peripheral wall or the inner peripheral wall and the extending wall have an annular shape with the same cross section.   The fluid pressure type clamp device according to any one of claims 1 to 4, wherein the outer peripheral wall or the inner peripheral wall and the extending wall are polygonal rings having the same cross section.   The shaft portion or the tubular portion is polygonal, and the working fluid chamber, the outer peripheral wall or the inner peripheral wall, and the extending wall are individually formed corresponding to respective sides of the polygonal shape. The fluid pressure type clamp device according to any one of Items 1 to 4.   The fluid pressure type clamp device according to any one of claims 1 to 7, wherein a recess for reducing the thickness of the tip wall is formed in the tip wall.

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