JP2007050478A - Clamping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a clamping device which simplifies axial movement of a mandrel type split collar, by rotating operation of a movable nut. <P>SOLUTION: According to the structure of the clamping device, a thin cylindrical body 4 which has a tapered external shape and expands its external diameter by an inner liquid body, is secured to a cylindrical body 1, and the almost cylindrical split collar 11 which has a tapered internal diameter and can vary its external diameter by its slit is inserted into a gap between the thin cylindrical body 4 and a workpiece W mounted on the same, followed by axially moving the split collar 11 by the movable nut 6, to thereby vary the external diameter of the split collar according to the tapered external shape of the thin cylindrical body 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an expansion-type clamping device having a built-in oil / gel-like substance for gripping a workpiece or a processing tool used in a machining field or a measurement field.

  The applicant has previously filed a so-called hydraulic mandrel chuck as a Japanese Patent Application No. 2004-29659.

  Since the hydraulic mandrel chuck is a clamp mechanism that expands to the outer shape side, in the structure shown in FIG. 4 of the prior application, the split collet 120 is pushed to the left to improve work efficiency and the like. After eliminating the initial clearance from the inner diameter side of the grasped member T2, the thin cylindrical member 110 is expanded by operating the hydraulic mechanism to fix the grasped member T2.

  At this time, if there is a mechanism for efficiently pushing the split collet 120, the operability is improved. In this case, the split collet 120 is pushed by hand. In particular, when the split collet 120 has a small diameter, it is difficult to incorporate such a mechanism and workability is poor.

  Moreover, as a well-known technique which shows a prior art, there exists what pushes in a thin sleeve by screwing a nut like patent document 1, for example. In addition, as in Patent Document 2, a component that presses the workpiece in the axial direction is applied by inclining the hydraulic chamber of the flange body and expanding the outer peripheral surface in an inclined manner when hydraulic pressure is applied. Are known.

Japanese Patent Publication No.54-39079 JP 2001-150354 A

  However, in the former patent document 1, since the nut structure is provided, the entire size is increased in the longitudinal direction, and in the latter patent document 2, a gap is large between the outer diameter of the hydraulic chamber and the inner diameter of the member to be gripped. In some cases, as in the above-mentioned prior application, the hydraulic chamber needs to be expanded before the initial clearance is eliminated, and the position stability of the gripped member during that time is poor.

  An object of the present invention is to solve the above-mentioned problems and use a split collar to enable efficient operation without changing the size of the mandrel chuck in the axial direction, thereby saving space and improving workability. It is to provide a clamping device.

  In order to achieve the above object, the technical feature of the clamping device according to the present invention is that a thin cylindrical body having a tapered outer shape and having an outer diameter expanded by a liquid body inside is fixed to a cylindrical body. And a to-be-held member mounted thereon, a substantially cylindrical split collar having a tapered inner diameter and an outer diameter being variable by a slit is inserted, and the split collar is moved in the axial direction by a moving nut, The outer diameter of the split collar is changed following the tapered outer shape of the thin cylindrical body.

  According to the clamping device of the present invention, the mandrel type split collar can be moved in the axial direction by rotating the moving nut.

  The present invention will be described in detail based on the embodiment shown in FIGS.

  1 is a longitudinal sectional view of the clamping device, FIG. 2 is a perspective view of an assembled state with a part cut away, and FIG. 3 is an exploded perspective view. The main components of the clamping device are a body 1, a moving nut 6, a ring member 7, a stopper 8, a nut ring 10, and a split collar 11.

  A hydraulic passage having a piston 2 and filled with, for example, oil O is formed in the central axis of the cylindrical body 1, and the piston 2 is moved in the axial direction by rotating the operation screw portion 3. ing. A flange portion 1a is formed at the center of the body 1, and a so-called shell is formed in front of the flange portion 1a, and a metal thin cylindrical body 4 having a small taper diameter is attached so as to become a small diameter as it advances to the tip. , And is fixed by a washer 5. The central portion of the thin cylindrical body 4 is an expansion portion 4a that expands by hydraulic pressure.

  A substantially annular moving nut 6 that can move in the axial direction is disposed on the body 1 in front of the flange portion 1a. A ring member 7 is interposed between the moving nut 6 and the body 1, and this ring member. 7 is fixed to the moving nut 6. And the movement nut 6 has the three convex parts 6a equally toward the outward of radial direction.

  On the other hand, the stopper 8 that abuts the workpiece W has three protruding portions 8a protruding rearward, and these protruding portions 8a are fitted between the protruding portions 6a of the moving nut 6 so that the protruding portions of the moving nut 6 are protruded. It is made longer than the thickness of the part 6a in the axial direction. The tips of these protrusions 8a are respectively screwed to the flange portion 1a with screws 9 to restrict the rotation of the moving nut 6 in the circumferential direction. The front end surface of the stopper 8 is a contact surface 8b for the workpiece W.

  The envelope of the outer periphery of the convex portion 6a of the moving nut 6 is circular, and a screw groove 6b is engraved in the circumferential direction on the outer periphery. A nut ring 10 having a screw on the inside rotates outside the screw groove 6b. The nut ring 10 itself is sandwiched between the flange portion 1a and the stopper 8 so as not to move in the axial direction.

  Furthermore, a substantially cylindrical split collar 11 having a large number of slits 11 a in the axial direction and having a variable outer diameter is disposed on the thin cylindrical body 4. The split collar 11 has a tapered shape in which the inner diameter is gradually reduced toward the front end. Further, the rear end of the split collar 11 is provided with an edge portion 11 b facing outward. The edge portion 11 b is pushed into the gap between the moving nut 6 and the body 1, and the edge portion 11 b is an edge portion 6 c of the moving nut 6. And the ring member 7 so as not to come out.

  With this configuration, when the nut ring 10 is rotated in the circumferential direction, the nut ring 10 moves the moving nut 6 in the axial direction via the thread groove 6b without moving its position in the axial direction, and follows this movement. Accordingly, the split collar 11 also moves in the axial direction. As the split collar 11 moves, the outer diameter of the thin cylindrical body 4 changes while maintaining the parallelism with respect to the axis due to the tapered shape of the outer surface of the thin cylindrical body 4 and the tapered shape provided on the inner surface of the split collar 11. . Note that the amount of movement of the split collar 11 is regulated by the movement of the moving nut 6 relative to the stopper 8, that is, the range in which the convex portion 6 a of the moving nut 6 is regulated by the protruding portion 8 a of the stopper 8.

  In use, when the work W is inserted into the body 1 as shown in FIG. 1 and is brought into contact with the contact surface 8b of the stopper 8, the work W is positioned on the expanding portion 4a in this state. Therefore, when the movable nut 6 is rotated and the split collar 11 is drawn between the flange portions 1a, the split collar 11 gradually follows the outer diameter of the thin cylindrical body 4 while gradually moving between the expanding portion 4a and the workpiece W. The diameter increases and the gap decreases.

  By moving the split collar 11 in the axial direction in this way, the gap between the workpiece W, that is, the initial clearance can be reduced. Therefore, the nut ring 10 is moved, and the split collar 11 is further moved in the axial direction to expand the diameter, so that the initial clearance can be made almost zero. In this state, the outer diameter of the split collar 11 and the inner diameter of the work W come into contact with each other, and the work W is further pulled in, so that the end face of the work W comes into contact with the contact surface 8 b of the stopper 8.

  At this stage, the initial clearance is zero, and thereafter, the operating screw portion 3 is rotated by, for example, a spanner to push the piston 2 to apply pressure to the internal oil O. By this hydraulic pressure, the expanding portion 4a expands radially outward and the diameter of the split collar 11 also expands, so that the workpiece W can be clamped to the body 1 with high accuracy and strength. At this time, since the workpiece W is in contact with the contact surface 8b of the stopper 8, the accuracy of the squareness of the workpiece W after clamping with respect to the axis of the body 1 is maintained.

  The concave and convex guide portions of the moving nut 6 and the stopper 8 corresponding to three equal parts can be divided into other numbers such as two equal parts, four equal parts, and six equal parts. Further, this division is not limited to equal division.

  The present invention can be applied not only to the expansion type mandrel but also to the contraction type chuck, and a rotation mechanism other than the nut ring 10 may be used for the rotation operation.

It is a longitudinal cross-sectional view of an Example. It is the perspective view which notched a part. It is a disassembled perspective view. It is sectional drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body 2 Piston 4 Thin cylindrical body 6 Moving nut 7 Ring member 8 Stopper 10 Nut ring 11% collar W Work O Oil

Claims (5)

  The cylindrical body has a tapered outer shape and a thin cylindrical body whose outer diameter is expanded by an internal liquid material is fixed, and a tapered inner diameter is provided between the thin cylindrical body and a member to be gripped mounted thereon. A substantially cylindrical split collar whose outer diameter is variable by a slit is inserted, the split collar is moved in the axial direction by a moving nut, and the outer diameter of the split collar is changed following the tapered outer shape of the thin cylindrical body. A clamping device characterized in that   The clamping device according to claim 1, wherein the split collar is moved by converting a circumferential rotational force applied to the moving nut from the outside into an axial movement.   The clamping device according to claim 2, wherein the moving nut applies a rotational force by a nut ring screwed to an outer periphery.   The clamp device according to claim 1 or 2, wherein the moving nut is restricted in rotation by a stopper fixed to the body and the amount of movement in the axial direction is restricted.   The clamp device according to claim 4, wherein the gripped member is brought into contact with and fixed to an end surface of the stopper.

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