JP5386256B2 - Chuck - Google Patents

Description

  The present invention relates to a chuck for holding a tool such as a drill on a spindle.

  When a hole is drilled in a workpiece using a small-diameter drill, it is necessary to rotate the drill at a high speed in order to ensure a cutting peripheral speed. However, in the case of a chuck (collet) using a conventional slit, a practical spindle rotation speed is about 200,000 rotations per minute, and at higher rotation speeds, the chuck has a holding force to hold the drill by centrifugal force. It was weak and difficult to process.

  Therefore, conventionally, a chuck having a plurality of collars arranged to wrap around the drill shaft, an outer rim support part arranged to be attached to the drill, and a clamping mechanism between the collar and the outer rim support part. Has been proposed (see Patent Document 1). In this chuck, the clamping mechanism is configured so that the collar grips the drill shaft tightly by applying a clamping force based on the centrifugal force and the eccentric ring retaining force force between the outer rim support and the collar, and the collar and the outer rim support. The part and the clamping mechanism are integrally formed from a single piece of material. By configuring the chuck in this way, the drill could be rotated at high speed.

JP 2002-535156 A

  However, the conventional chuck has a structure in which a plurality of collars are oscillated and clamped by centrifugal force. Therefore, when the mass of the plurality of collars is different, or the contact point between the collar and the drill at the time of processing is the circumferential direction. If they are not evenly spaced, the axis of the held drill may deviate from the designed axis.

  For this reason, it is necessary to create a plurality of colors with high accuracy because of the need to reduce processing tolerances, which increases the cost.

  Accordingly, an object of the present invention is to provide a chuck that can prevent the axial center of a held tool from deviating from the designed axial center.

The present invention (see, for example, FIGS. 1, 2 and 5 ) is a chuck mounted on a spindle (10) for holding a tool (14),
An inner cylinder (2) formed in a cylindrical shape whose inner diameter is larger than the shank diameter of the tool (14);
An outer cylinder (3) having an inner diameter that is larger than the outer diameter of the inner cylinder (2) and arranged coaxially with the inner cylinder (2);
Disposed at equal intervals in the circumferential direction, the outer peripheral surface (2b) of the inner cylinder (2) and the inner peripheral surface (3a) of the outer cylinder (3) are connected, and the centrifugal operation is performed by the rotation of the spindle (10). A plurality of connecting portions (4 ) that move in the radial direction by force to deform the inner cylinder (2);
A plurality of flange portions (3f) provided on the outer peripheral surface (3b) of the outer cylinder (3) so as to protrude in the radial direction and pressed against the spindle (10) ;
The inner peripheral surface of the inner cylinder (2) (2a) by pressure contact to the tool (14) holding the tool (14) by the deformation of the inner tube (2),
The connecting portion (4) extends in the radial direction from the outer peripheral surface (2b) of the inner cylinder (2) toward the inner peripheral surface (3a) of the outer cylinder (3), and is connected to the inner cylinder (2). The outer peripheral surface (2b) and the inner peripheral surface (3a) of the outer cylinder (3) are connected and moved in the radial direction along with the deformation of the outer cylinder (3) by the centrifugal force generated by the rotation of the spindle (10). Rib (4),
The flange portion (3f) forms a space (R) allowing deformation of the outer cylinder (3) between the outer peripheral surface (3b) of the outer cylinder (3) and the spindle (10).
The chucks (1) and (1A ) are characterized by the above.

The chuck (1A) includes a protrusion (5) disposed on an extension line of the rib (4) and provided on an outer peripheral surface (3b) of the outer cylinder (3).
It is characterized by this.

Further, the present invention (see, for example, FIGS. 2 and 6) is a chuck that is mounted on the spindle (10) and holds the tool (14).
An inner cylinder (2) formed in a cylindrical shape whose inner diameter is larger than the shank diameter of the tool (14);
An outer cylinder (3) having an inner diameter that is larger than the outer diameter of the inner cylinder (2) and arranged coaxially with the inner cylinder (2);
Disposed at equal intervals in the circumferential direction, the outer peripheral surface (2b) of the inner cylinder (2) and the inner peripheral surface (3a) of the outer cylinder (3) are connected, and the centrifugal operation is performed by the rotation of the spindle (10). A plurality of connecting portions (4B) that move in the radial direction by force to deform the inner cylinder (2),
Due to the deformation of the inner cylinder (2), the inner peripheral surface (2a) of the inner cylinder (2) is pressed against the tool (14) to hold the tool (14),
The connecting portion (4B)
A string-like member (4b) provided on the inner peripheral surface (3a) of the outer cylinder (3) so as to connect an arc of a predetermined distance on the inner peripheral surface (3a) of the outer cylinder (3);
The inner cylinder (2) extends in the radial direction from the outer peripheral surface (2b) of the outer cylinder (3) toward the inner peripheral surface (3a) of the outer cylinder (3), and the outer peripheral surface (2b) of the inner cylinder (2) and the chordal shape A connecting member (4a) for connecting the center of the member (4b),
It is in the chuck | zipper (1B) characterized by this.

The chuck (1B) includes a protrusion (6) that is disposed on an extension line of the connection member (4a) and protrudes toward the outer cylinder (3) of the string member (4b). The
It is characterized by this.

  In addition, although the code | symbol in the said parenthesis is for contrast with drawing, this is for convenience for making an understanding of invention easy, and has no influence on the structure of a claim. It is not a thing.

  According to the present invention, since the inner cylinder is deformed and the inner peripheral surface of the inner cylinder is pressed against the tool, the tool is firmly held on the inner peripheral surface of the inner cylinder. Since the inner cylinder is deformed by pulling a plurality of connecting portions arranged at equal intervals in the circumferential direction, the inner circumferential surface of the inner cylinder is in surface contact with the tool at equal intervals in the circumferential direction. It is possible to prevent the shaft center from deviating from the designed shaft center.

It is a block diagram of the chuck | zipper in 1st Embodiment of this invention. It is sectional drawing of the spindle which supports a chuck | zipper. It is a schematic diagram explaining operation | movement of a chuck | zipper. It is explanatory drawing of the tool holding force of a chuck | zipper. It is a block diagram of the chuck | zipper in 2nd Embodiment of this invention. It is a block diagram of the chuck | zipper in 3rd Embodiment of this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  1A and 1B are configuration diagrams of a chuck according to a first embodiment of the present invention, in which FIG. 1A is a plan view, FIG. 1B is a sectional view taken along line AA in FIG. 1A, and FIG. It is B sectional drawing. FIG. 2 is a cross-sectional view of the spindle that supports the chuck.

  The chuck 1 shown in FIG. 1 includes an inner cylinder 2 that holds a tool 14 (FIG. 2), an outer cylinder 3 that is held by a spindle 10 (FIG. 2), and a plurality of (which connects the inner cylinder 2 and the outer cylinder 3). 3) in the first embodiment, and the rib 4 serving as a connecting portion is attached to the spindle 10. The inner cylinder 2 has a hollow cylindrical shape, and its inner diameter is slightly larger (for example, 2 μm) than the shank diameter of the tool 14 to be held. The outer cylinder 3 has a hollow cylindrical shape whose inner diameter is larger than the outer diameter of the inner cylinder 2. The outer cylinder 3 is disposed coaxially with the inner cylinder 2. At both ends of the outer cylinder 3 in the direction of the axis O, a plurality (two) of flange portions 3f projecting in the radial direction from the outer peripheral surface 3b of the outer cylinder 3 are provided. The inner cylinder 2 disposed at a substantially central portion in the direction of the axis O of the outer cylinder 3 is connected to the outer cylinder 3 by each rib 4. The outer cylinder 3 is formed such that the length in the axis O direction is longer than the length of the inner cylinder 2 in the axis O direction.

  The ribs 4 are arranged at equal intervals in the circumferential direction of the inner cylinder 2 (in the first embodiment, at intervals of 120 degrees). Each rib 4 is arranged orthogonal to the outer peripheral surface 2b of the inner cylinder 2 and the inner peripheral surface 3a of the outer cylinder 3, and is radially directed from the outer peripheral surface 2b of the inner cylinder 2 toward the inner peripheral surface 3a of the outer cylinder 3. The outer peripheral surface 2b of the inner cylinder 2 and the inner peripheral surface 3a of the outer cylinder 3 are connected to each other. Each rib 4 is formed so that the length in the axis O direction is equal to the length in the axis O direction of the inner cylinder 2, and the outer peripheral surface 2 b of the inner cylinder 2 and the inner peripheral surface 3 a of the outer cylinder 3 are connected to the axis O of the inner cylinder 2. It is connected over the entire length in the direction.

  When the outer diameter of the outer cylinder 3 is D and the total length is L, for example, the chuck 1 can be formed by electric discharge machining from a cylindrical material having the outer diameter D and the total length L.

  As shown in FIG. 2A, the chuck 1 is held by a rotatable spindle 10 such that the axis O is coaxial with the axis of the spindle 10. The chuck 1 is prevented from rotating with respect to the spindle 10 by press-fitting or means not shown. At this time, the two flange portions 3f are in pressure contact with the spindle 10, and a space R is formed between the spindle 10 and the outer peripheral surface 3b of the outer cylinder 3 by the two flange portions 3f. A tool stopper 11 having a blind hole 11a is disposed above the chuck 1 in FIG. 2, and an O-ring holder 12 is disposed below. An O-ring 13 is disposed on the tool stopper 11 and the O-ring holder 12. The inner diameter of the O-ring 13 when the tool 14 is not inserted is 0.2 mm to 0.5 mm smaller than the outer diameter (shank diameter) of the shank 14 s of the tool 14. When the tool 14 is inserted into the O-ring 13 as shown in FIG. 5B, the tool 14 is held on the O-ring 13, that is, the spindle 10 due to the frictional force with the O-ring 13. Although two O-rings 13 are provided, one O-ring 13 may be provided.

  Next, the operation of the chuck 1 when the spindle 10 is rotated and machining is performed with the tool 14 will be described.

  FIG. 3 is a schematic diagram for explaining the operation of the chuck 1 shown in FIG. In the figure, the tool 14 is indicated by a dotted line.

  When the spindle 10 is rotated, the spindle 10 and the chuck 1 receive a force in a radial direction due to the centrifugal force caused by the rotation. At this time, assuming that there is no tool 14, centrifugal force acts on each rib 4 and the outer cylinder 3, so that each rib 4 moves in the radial direction of the inner cylinder 2, and the inner cylinder 2 is radiused by each rib 4. Deformed by pulling in the direction. In the first embodiment, since the chuck 1 has the three ribs 4, it is deformed into a rounded triangle (a rice ball type).

  Therefore, when the tool 14 is inserted into the chuck 1, a force corresponding to the deformation of the K portion in FIG. That is, the inner cylinder 2 is deformed by the gap between the inner peripheral surface 2 a and the shank 14 s of the tool 14, and the inner peripheral surface 2 a is pressed against the shank 14 s of the tool 14. Specifically, a portion between the rib 4 and the rib 4 on the inner peripheral surface 2a of the inner cylinder 2 comes into pressure contact with the shank 14s. The tool 14 is firmly held on the chuck 1 by the frictional force between the inner peripheral surface 2a of the inner cylinder 2 and the shank 14s of the tool 14 when the inner peripheral surface 2a of the inner cylinder 2 is in pressure contact with the shank 14s of the tool 14. The Since the three ribs 4 are arranged at equal intervals in the circumferential direction, the portion between the rib 4 and the rib 4 on the inner circumferential surface 2a of the inner cylinder 2 is arranged on the tool 14 at equal intervals in the circumferential direction. Press contact with surface contact. Therefore, the pressing force of the inner peripheral surface 2a of the inner cylinder 2 that press-contacts the shank 14s of the tool 14 is uniform in the circumferential direction, and the tool 14 is held without being deviated from the design axis. Since a space R is formed between the outer peripheral surface 3 b of the outer cylinder 3 of the chuck 1 and the spindle 10 as shown in FIG. 2, the outer cylinder 3 is moved by the radial movement of each rib 4. Is allowed to deform. That is, the outer cylinder 3 is deformed so that a portion corresponding to the rib 4 protrudes toward the space R, and each rib 4 moves in the radial direction along with the deformation of the outer cylinder 3. Further, the flange portions 3f provided at both ends of the outer cylinder 3 in the direction of the axis O are maintained in a pressure contact state even when the outer cylinder 3 is deformed, and the rotation of the chuck 1 with respect to the spindle 10 is retained.

  Next, the force with which the chuck 1 holds the tool 14 will be specifically described.

4A and 4B are explanatory diagrams of the tool holding force of the chuck 1 according to the present invention, in which FIG. 4A is a diagram showing the relationship between the rotational speed of the spindle 10 and the holding force of the tool 14, and FIG. (C) is side surface sectional drawing.
The dimensions of each part of the chuck 1 are as follows:
Outer diameter of inner cylinder 2 d1: 4.5 mm
Inner cylinder 2 inner diameter d2: 3.18 mm
Total length L1 of inner cylinder 2: 14 mm
The outer diameter D1 of the flange portion 3f of the outer cylinder 3 is 12 mm.
The outer diameter D2 of the center part of the outer cylinder 3: 11.5 mm
Inner cylinder 3 inner diameter D3: 10 mm
Distance l2 from the end of the outer cylinder 3 to the end of the inner cylinder 2: 2 mm
Overall length L2 of the outer cylinder 3: 18 mm
Length of flange 3f of outer cylinder 3 l2: 1 mm
Rib 4 width t: 1 mm
Material: SUS440C (JIS G4303)
It is.

  As shown in FIG. 4, the holding force of the tool 14 increases as the number of rotations of the spindle 10 increases, and a practically sufficient tool holding force can be obtained as long as it is 100,000 revolutions per minute or more. In addition, you may make the full length (length L1 in FIG.4 (b)) of the inner cylinder 2 equal to the full length (length L2 in FIG.4 (b)) of the outer cylinder 3. FIG.

  As described above, the tool 14 is held by the inner cylinder 2 by the centrifugal force according to the rotational speed of the spindle 10, so that the structure is simple and the manufacturing cost is low, but the axis of the held tool 14. Can be prevented from deviating from the design axis.

  Next, a chuck according to a second embodiment of the present invention will be described.

  FIG. 5: is a block diagram of the chuck | zipper in 2nd Embodiment of this invention, (a) is a top view, (b) is CC sectional drawing of (a), (c) is DD of (b). It is D sectional drawing. In addition, the same thing as FIG. 1 or the thing of the same function attaches | subjects the same code | symbol, and abbreviate | omits the overlapping description.

  The chuck 1A shown in FIG. 5 is arranged on the extension line of the rib 4, is provided on the outer peripheral surface 3b of the outer cylinder 3, and has a plurality (three in the second embodiment) of the same number of ribs 4 as connecting portions. A protrusion 5 is provided. Each protrusion 5 is formed so that the length in the direction of the axis O is equal to the length of the inner cylinder 2 in the direction of the axis O, and has the same width as the rib 4 over the entire length. Further, each protrusion 5 is set such that the radial protrusion amount from the outer peripheral surface 3b is smaller than the radial protrusion amount of the flange portion 3f, and when mounted on the spindle, the non-rotating spindle It is in a non-contact state. The total length of the inner cylinder 2 may be equal to the total length of the outer cylinder 3.

  Even with such a shape, it is possible to obtain the same performance as that of the chuck shown in FIG. 1, and the same effects as those of the first embodiment can be obtained.

  The protrusion 5 receives a centrifugal force in the radial direction when the spindle rotates. Then, a tensile force in the radial direction due to the centrifugal force acting on the protrusion 5 acts on the rib 4, and the tool can be held more effectively.

  Furthermore, by forming a recess (not shown) in which the protrusion 5 fits on a spindle (not shown), the protrusion 5 can function as a detent of the chuck 1A when the spindle rotates.

  Next, a chuck according to a third embodiment of the present invention will be described.

  FIG. 6 is a plan view of the chuck 1B according to the third embodiment of the present invention. In addition, the same thing as FIG. 1 or the thing of the same function attaches | subjects the same code | symbol, and abbreviate | omits the overlapping description. In the case of this chuck 1B, the total length of the outer cylinder 3 is the same as the total length of the inner cylinder 2.

  A chuck 1B shown in FIG. 6 includes a plurality (three in the third embodiment) of connecting portions 4B. The connecting portions 4B are arranged at equal intervals in the circumferential direction (in the third embodiment, at intervals of 120 degrees). Each connecting portion 4B includes a connecting member 4a and a string-like member 4b.

  First, the string-like member 4b is provided on the inner peripheral surface 3a of the outer cylinder 3 so as to form a predetermined distance arc of the inner peripheral surface 3a of the outer cylinder 3. In other words, the string-like member 4 b extends in a direction orthogonal to the radial direction, and both ends thereof are connected to the inner peripheral surface 3 a of the outer cylinder 3. The string-like member 4b is formed so as to extend over the entire length of the inner cylinder 2 in the axis O direction.

  The connecting member 4a extends in the radial direction from the outer peripheral surface 2b of the inner cylinder 2 toward the inner peripheral surface 3a of the outer cylinder 3, and connects the outer peripheral surface 2b of the inner cylinder 2 and the center of the string member 4b. The connection member 4a is orthogonal to the outer peripheral surface 2b of the inner cylinder 2 and is orthogonal to the chord member 4b.

  The chuck 1B includes a protrusion 6 provided on the string member 4b. The protrusion 6 is disposed on the extension line of the connection member 4a, and is formed so as to protrude from the center of the string member 4b toward the outer cylinder 3 side. The protruding direction of the protrusion 6 is orthogonal to the string member 4b. The protrusion 6 is formed so that the length in the direction of the axis O is equal to the length of the inner cylinder 2 in the direction of the axis O, and is set to have the same width as the connection member 4a. A gap is formed between the tip surface of the protrusion 6 and the inner peripheral surface 3 a of the outer cylinder 3. The chuck 1B is formed from a cylindrical material by electric discharge machining.

  With the above configuration, when the spindle that supports the chuck 1B is rotated, the inner cylinder 2 is pulled and deformed by centrifugal force in the radial direction by the connecting portions 4B.

  At this time, a force that moves in the radial direction due to centrifugal force acts on the connection member 4a of each connecting portion 4B, and the center of the string-like member 4b is pressed by the connection member 4a to bend in the radial direction. As a result, the inner cylinder 2 and the connecting portion 4B are deformed. The deforming force is distributed to the outer cylinder 3 at six points and works equally, and the outer cylinder 3 is hardly deformed. And the tensile force of the connection part 4B by the centrifugal force which acts on the connection part 4B acts on the inner cylinder 2 more effectively, and it can hold | maintain a tool more effectively.

  Further, since the centrifugal force also acts on the protrusion 6, the connection member 4 a is further applied with a force for deforming the inner cylinder 2 by the amount of the centrifugal force that acts on the protrusion 6, thereby more effectively reducing the tool. Can be held. Note that the protrusion 6 in FIG. 6 can be omitted.

  The total length of the inner cylinder 2 may be about 6 mm.

  In addition, although this invention was demonstrated based on the said embodiment, this invention is not limited to this. In the above embodiment, the case where three connecting portions 4 or 4B are provided has been described. However, the present invention is not limited to this, and two or four or more may be arranged at equal intervals in the circumferential direction.

1, 1A, 1B Chuck 2 Inner cylinder 2a Inner peripheral surface 2b Outer peripheral surface 3 Outer cylinder 3a Inner peripheral surface 3b Outer peripheral surface 3f Flange portion 4 Rib (connecting portion)
4B Connecting portion 4a Connecting member 4b String member 5 Protruding portion 6 Protruding portion 10 Spindle 14 Tool 14s Shank R Space

Claims (4)

In the chuck that is attached to the spindle and holds the tool,
An inner cylinder formed in a cylindrical shape having an inner diameter larger than the shank diameter of the tool;
An outer cylinder that has an inner diameter that is larger than the outer diameter of the inner cylinder and is arranged coaxially with the inner cylinder;
Plurally arranged at equal intervals in the circumferential direction, connecting the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, and deforming the inner cylinder by moving in the radial direction by centrifugal force due to rotation of the spindle A connecting portion of
A plurality of flange portions provided on the outer peripheral surface of the outer cylinder so as to protrude in the radial direction, and in pressure contact with the spindle ,
And it is pressed against the inner peripheral surface of the inner cylinder to the tool by holding the tool by the deformation of the inner tube,
The connecting portion extends in the radial direction from the outer peripheral surface of the inner cylinder toward the inner peripheral surface of the outer cylinder, connects the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, and A rib that moves in the radial direction along with the deformation of the outer cylinder by centrifugal force due to rotation;
The flange portion forms a space allowing deformation of the outer cylinder between the outer peripheral surface of the outer cylinder and the spindle.
A chuck characterized by that. Arranged on an extension line of the rib, and provided with a protrusion provided on the outer peripheral surface of the outer cylinder,
The chuck according to claim 1 . In the chuck that is attached to the spindle and holds the tool,
An inner cylinder formed in a cylindrical shape having an inner diameter larger than the shank diameter of the tool;
An outer cylinder that has an inner diameter that is larger than the outer diameter of the inner cylinder and is arranged coaxially with the inner cylinder;
Plurally arranged at equal intervals in the circumferential direction, connecting the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, and deforming the inner cylinder by moving in the radial direction by centrifugal force due to rotation of the spindle A connecting portion,
Holding the tool by pressing the inner peripheral surface of the inner cylinder against the tool by deformation of the inner cylinder;
The connecting portion is
A string-like member provided on the inner peripheral surface of the outer cylinder so as to tie an arc of a predetermined distance on the inner peripheral surface of the outer cylinder;
A connecting member that extends in a radial direction from the outer peripheral surface of the inner cylinder toward the inner peripheral surface of the outer cylinder, and that connects the outer peripheral surface of the inner cylinder and the center of the string member;
Features and to Ruchi jack that. Provided on the extension line of the connection member, and provided with a protrusion formed to protrude to the outer cylinder side of the string member,
The chuck according to claim 3 .

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