JP2008137117A - Cutting edge replaceable self clamp cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting edge replaceable self clamp cutting tool which fixes a tip by using flexibly returning force of a pressing portion formed at a tool main body, and improves the tip clamping stability and fixing force of the cutting tool, in a manner naturally absorbing accuracy errors and bringing the tip into contact with the pressing portion in a wide range, without enhancing the accuracy of the tip and the pressing portion. <P>SOLUTION: According to the structure of the self clamp cutting tool, each clamp groove 3 having a main seat surface 3a and the pressing portion 3b opposed to the main seat surface, is formed in the tool main body 2, and the cutting edge tip 20 is fitted into a gap between the main seat surface 3a of the clamp groove and the pressing portion 3b of the same, for generating pressing force by flexible returning force, and fixed to the same. Then each slit 7 which is opened toward a recessed portion 6 at a bottom of the pressing portion and can elastically deform an internal edge of the pressing portion in a slit width direction, is formed in the tool main body 2, on one side of a pressing surface 3d of the pressing portion, away from the clamp groove 3, in a manner extending along the pressing surface 3d. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  This invention is a so-called self-clamping blade-tip-replaceable cutting tool that press-fits a cutting edge tip into a clamp groove provided in a tool body and fixes the cutting edge tip with an elastic restoring force of a pressing portion provided in the tool body (this In the invention, this is referred to as a blade-exchangeable self-clamp cutting tool).

  As a prior art of a blade-tip-exchange-type self-clamp cutting tool, for example, there are those disclosed in Patent Documents 1 to 3 below.

  The tool disclosed in Patent Document 1 is a milling tool, and has a clamp groove (seat portion) on the outer periphery of a disk-shaped tool body (supporting means). The clamp groove includes a seat surface that supports the surface of the cutting edge tip (hereinafter simply referred to as a tip) on the side of the rake face, and a pressing portion that faces the seat surface. Insert the tip (insert) by press fitting. The pressing portion of the tool is formed by an elastically deformable protrusion defined by radial slits (slots) before and after the rotation direction, and is formed by a nose portion of the protrusion, and the pressing portion is an elastic restoring force of the protrusion. The chip is clamped by pressing against the chip.

The tools disclosed in Patent Documents 2 and 3 are all bites. Formed on the tip of the plate-like holder is an outwardly expanding tapered tip mounting seat that opens to the tip and both sides of the holder. The lower jaw (bottom wall) of the tip mounting seat and the upper jaw (upper surface) that can be elastically deformed A wedge-shaped tip is press-fitted between the walls), and the tip is sandwiched between the lower jaws by the elastic restoring force of the upper jaw. In addition to Patent Documents 2 and 3, many proposals have been made on self-clamping tools employing a similar clamp structure.
Japanese National Patent Publication No. 10-509659 Japanese Utility Model Publication No. 1-66904 Japanese Utility Model Publication No. 2-50004

  In the chip clamp structure disclosed in the above-mentioned Patent Document 1, when the elastically deformed protrusion presses the chip with a restoring force, the pressing portion (nose portion) of the protrusion contacts only a part of the chip. Therefore, the fixing of the tip largely depends on the frictional force between the seating surface of the clamp groove and the back surface of the tip supported by the seating surface, and stable tip fixing is difficult to expect. Further, if the contact area between the protrusion and the chip is to be increased, high accuracy is required for the mutual contact surface.

A general chip is a sintered body, and many chips are provided with a sintered skin left in view of cost reduction. In particular, chips that leave the sintered skin tend to have low dimensional accuracy and shape accuracy. The dimensional accuracy and shape accuracy of the nose portion of the protrusion that constitutes the pressing portion also decreases depending on the processing situation.
Further, the elastic deformation of the protrusion occurs with the root as a fulcrum, and the deformation changes the direction of the pressing surface of the protrusion (angle formed with the seat surface). It is extremely difficult to machine the tip and protrusion so that the direction of the pressing surface and the clamped surface of the tip is completely aligned at the end of press-fitting of the tip. Because it is a partial contact on the radial side (contact close to line contact), the tip fixing greatly depends on the frictional force between the back surface and the seating surface, and the stability and fixing force of the clamp are insufficient. .

  The clamp structures disclosed in Patent Documents 2 and 3 also have the same problems as Patent Document 1. When the opening angle of the mouth of the chip mounting seat is larger than the wedge angle of the chip mounting portion, the upper jaw of the holder comes into partial contact with the chip. Even if the opening angle of the mouth of the tip mounting seat is the same as the wedge angle of the tip mounting portion, the same situation occurs because the opening angle of the mouth of the tip mounting seat changes due to the press-fitting of the tip. The contact area is small and the stability and fixing force of the chip clamp are reduced.

  Even if the accuracy of the pressing portion provided on the tip or the tool main body is not increased, the present invention allows the accuracy error to be naturally absorbed and the contact between the tip and the pressing portion to be made in a wide range of areas. The problem is to improve the stability and fixing force of the clamp of the chip.

In order to solve the above-described problems, in the present invention, a plate provided with a clamp groove having a chip, a main seating surface for supporting the back surface of the chip, and an elastically deformable pressing portion opposed to the main seating surface. A blade-type replaceable self-clamp cutting tool that is fixed between the main seating surface of the clamp groove and the pressing portion that generates a pressing force by elastic restoration. And a slit that opens toward the base portion of the pressing portion and allows the inner end side of the pressing portion to be elastically deformed in the slit width direction on the tool body of the cutting tool. It was formed so as to be along the pressing surface at a position further away from the clamp groove.

  It is preferable that the clamp groove of the tool is a groove inclined at an angle α with respect to the main seat surface so that the pressing surface of the pressing portion is widened on the entrance side of the clamp groove.

  As a specific example of this tool, a plurality of clamp grooves, slits, and chip pockets corresponding to each clamp groove are provided in the circumferential direction on the outer periphery of a plate-shaped tool body that is mounted on a drive shaft and rotated. A cutting edge exchange type metal saw is provided, and a cutting tool including a plate holder as a main body is also conceivable.

  A tool configured as a blade-exchange-type metal saw has an outer end opened in a chip pocket, and a second slit having an inner end inserted inward in the radial direction from the pressing portion is more forward in the rotational direction of the tool body than the slit. Further, it is preferable that the pressing portion be elastically deformable with a connecting portion between the clamp body and the tool body left between the clamp groove and the second slit as a fulcrum.

  In the metal saw having the second slit, the second slit is angled in the direction in which the inner end side is separated from the main seat surface with respect to the arc slit having the center on the clamp groove side or the main seat surface of the clamp groove. A slit having a slope of γ is preferable.

  In addition, the metal saw having the second slit is provided with a clamp screw that is press-fitted toward the center side of the tool body and pushes the pressing portion in a direction in which the pressing portion is elastically restored in a portion where the second slit is formed. Can do.

  The tool of the present invention is elastically deformed so that when the pressing surface of the pressing portion is pressed against the chip only on the entrance side of the clamp groove, the pressing groove opens the mouth with the root side serving as a fulcrum. As a result, the contact area of the pressing surface with respect to the chip is expanded, and the stability of the clamp is increased. Although this operation and effect can be obtained with the tools disclosed in Patent Documents 2 and 3, the function of correcting the situation when the pressing surface is pressed against the chip only at the back end side of the clamp groove is There is no conventional tool.

  On the other hand, in the present invention, a slit that opens toward the sag portion provided at the inner side of the inner end of the pressing portion is located along the pressing surface at a position farther from the clamp groove than the pressing surface of the pressing portion. As a result, when the situation where the pressing surface is pressed against the chip only on the inner end side (the far end side of the clamp groove), the inner end side portion of the pressing surface is elastically deformed with the vicinity of the outer end of the slit as a fulcrum. For this reason, the outer end side of the pressing surface also comes into contact with the chip, the contact area between the pressing portion and the chip is expanded, and each portion of the pressing surface is pressed against the chip with an average force. .

  The situation where only the outer end side or only the inner end side of the pressing surface of the pressing part contacts the chip occurs when the dimensional accuracy and shape accuracy of the chip and the pressing part are not sufficient. Therefore, it is not necessary to increase the dimensional accuracy and shape accuracy of the chip and the pressing portion.

  In addition, if the clamp groove has a shape in which the groove width is widened on the entrance side, the pressing force acts strongly on the back end side of the clamp groove due to the wedge effect of the groove, and the surface pressure is evenly applied to each area of the pressing surface. be able to.

  Moreover, the tool comprised as a blade-tip-exchange-type metal saw which further provided the second slit in the tool body has an elastic restoring force of the pressing portion depending on the size, shape, installation point, etc. of the second slit. Since it changes, it becomes easy to adjust the pressing force.

  For example, when the second slit is an arc slit having a center on the clamp groove side, the dimension of the pressing part (dimension in the tool circumferential direction) becomes smaller on the root side of the pressing part, so that the elastic restoring force of the pressing part The second slit is inclined at an angle γ in the direction in which the inner end side is separated from the main seat surface with respect to the main seat surface of the clamp groove. Since the dimension of the pressing portion increases on the base side of the pressing portion, the elastic restoring force of the pressing portion can be increased to increase the fixing force of the chip.

  Furthermore, a metal saw having a second slit, which is provided with a clamp screw at the portion where the second slit is formed, assists the pressing of the chip by the pressing part by tightening the clamp screw, thereby increasing the fixing force of the chip. Can be made.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a blade edge replaceable self-clamp cutting tool according to the present invention will be described below with reference to FIGS.

  FIGS. 1-7 has shown the example which applied this invention to the blade-tip-exchange-type metal saw. As shown in FIG. 1, the illustrated blade-tip-exchangeable metal saw 1 is configured by attaching tips (cutting edge tips) 20 to a plurality of clamp grooves 3 provided on the outer periphery of a disk-shaped tool body 2.

  As shown in FIG. 8, the tip 20 has a cutting edge 21 formed by a ridge line at a portion where the rake face 22 and the flank 23 intersect, and the front face 24 and the rear face 25 of the mounting portion connected to the rake face 22 are formed. When viewed from the flank 23 side, the two flat surfaces intersect at an angle θ (see FIG. 4) to form a V groove. The front surface 24 and the rear surface 25 of the illustrated chip 20 have the groove bottoms of the V-grooves parallel to each other, but when the clamp groove 3 is an outwardly extending wedge groove, a taper corresponding to the groove is attached to the mounting portion. Also good.

  The tool body 2 has a shaft hole 4 with a keyway as a center, and a drive shaft (not shown) of a processing machine is engaged with the shaft hole 4 so as to be rotated by the drive shaft. . On the outer periphery of the tool body 2, the above-described clamp grooves 3, a chip pocket 5 corresponding to each clamp groove 3, a relief portion 6 provided at the root portion of the pressing portion and connected to the clamp groove 3, The slits 7 that characterize the present invention are provided at a constant pitch in the circumferential direction.

  Each clamp groove 3 supports the main seating surface 3a for supporting the back surface 25 of the tip, the pressing portion 3b opposed to the main seating surface 3a, and the end surface 26 of the tip to position the tip 20 in the tool radial direction. It has a secondary seating surface 3c. The positioning of the tip 20 in the tool radial direction can also be performed by providing the tip 20 with a protrusion that abuts against the outer diameter surface of the pressing portion 3b. In this case, the sub seat surface 3c is unnecessary.

  As shown in FIGS. 2 and 4, the main seating surface 3 a has a chevron surface corresponding to the V groove of the back surface 25 of the chip. Further, the pressing portion 3b is formed integrally with the tool body 2, and the pressing surface 3d of this pressing portion also has a chevron surface corresponding to the V groove of the front surface 24 of the chip.

  The main seating surface 3a, the back surface 25 of the chip seated on the main seating surface, and the pressing surface 3d of the pressing portion 3b and the front surface 24 of the chip are formed so as to be V-shaped. Although it is preferable in preventing the shift to the direction, it is not an essential requirement. Tip centering and shift prevention can also be achieved by providing a groove other than the V-groove and a pin engaged with the groove.

  The pressing surface 3d of the pressing portion 3b may be parallel to the main seating surface 3a, but as shown in FIG. 3, the pressing surface 3d is on the entrance side of the clamp groove 3 with respect to the main seating surface 3a. When the angle α is inclined in the direction in which the groove width widens, the clamp groove 3 produces a wedge effect, and the pressing force acts strongly on the back end side of the clamp groove 3, and the surface pressure is more evenly applied to each region of the pressing surface 3 d. Can be applied. Note that an appropriate value of α is about 2 ≦ 1 °.

  The pressing part 3b and the chip pocket 5 are arranged ahead of the clamp groove 3 in the rotation direction of the tool. Further, the thinning portion 6 is provided in a state where the tool center side portion is passed from the inner end of the pressing portion 3 b at a position continuous with the clamp groove 3.

  The slit 7 is formed along the pressing surface 3d at a position farther from the clamp groove 3 than the pressing surface 3d of the pressing portion 3b. The slit 7 has an outer end in the middle of the pressing portion 3 b in the radial direction, and an inner end of the slit 7 is open to the thin portion 6. As shown in FIG. 3, the slit 7 has an inclination of an angle β with respect to the pressing surface 3d (the direction of the inclination can be opposite to that in FIG. 3) or parallel to the pressing surface 3d. There may be.

  In the tool body 2, a second slit 8 having an outer end opened in the chip pocket 5 and an inner end entering inward in the radial direction from the pressing portion 3b is further positioned forward of the slit 7 in the rotational direction. Provided. When the second slit 8 is provided, the pressing portion 3b can be elastically deformed with the connecting portion 11 to the tool body as a fulcrum, and the elastic restoring force (ie, pressing force) of the pressing portion 3b can be easily adjusted.

  In FIG. 1 and FIG. 3, the second slit 8 is a linear slit having an inclination of an angle γ in the direction in which the inner end side is separated from the main seat surface 3a with respect to the main seat surface 3a. As shown in FIG. 6, it may be a circular slit having a radius R and having a center on the clamp groove 3 side.

  The second slit 8 having the shape shown in FIGS. 1 and 3 increases the elastic restoring force of the pressing portion 3b because the size (width in the tool circumferential direction) of the pressing portion 3b increases on the base side of the pressing portion. On the other hand, the second slit 8 having the shape shown in FIGS. 5 and 6 can elastically deform the pressing portion 3b because the size of the pressing portion 3b becomes smaller on the root side of the pressing portion. Easy to do.

  The illustrated blade-tip replaceable metal saw 1 configured as described above is used by inserting a tip 20 into each clamp groove 3 on the outer periphery of the tool body 2 by press-fitting. Removal of the press-fitted tip 20 is performed by forcibly expanding the clamp groove 3 using a tool.

  When the situation where the pressing surface 3d of the pressing portion 3b is pressed against the chip 20 only on the entrance side of the clamp groove 3 occurs as shown in FIG. Acts on the outer diameter side portion (the portion of L1) of the pressing portion 3b rather than the connecting portion 11, and therefore, the pressing portion 3b is elastically deformed so that the clamp groove opens the mouth with the connecting portion 11 as a fulcrum, Further, when a situation occurs in which the pressing surface 3d is pressed against the chip 20 only at the back end side of the clamp groove 3, the portion of the load from F2 between the inner end of the pressing portion 3b and the outer end of the slit 7 (L2 And the inner end side of the pressing portion 3b is elastically deformed in the direction in which the mouth of the slit 7 is closed with the vicinity of the outer end of the slit 7 as a fulcrum, and the outer diameter side of the pressing surface 3d is also moved by this self-correcting action. I touch the tip 20 Contact area becomes spread, so each section of the pressing surface is pressed against the chip average force.

  In the metal saw provided with the second slit 8, as shown in FIG. 7, a screw screw 9 is provided in a portion where the second slit 8 is formed, and a clamp screw 10 having a tapered taper head 10a is provided in the screw hole. It is also possible to use a structure that is screwed into 9. In this structure, when the clamp screw 10 is tightened, the pressing portion 3b is pressed in a direction in which it is elastically restored by the wedge action of the head of the clamp screw 10. Thereby, the pressing by the pressing portion 3b is assisted, the fixing force of the chip is increased, and the stability of the clamp is further increased.

  FIG. 9 shows an example in which the present invention is applied to a cutting tool that performs grooving or parting. The illustrated cutting tool 30 is provided with a clamp groove 3 in an upper corner portion at the tip of a plate-like tool body (holder) 2. The clamp groove 3 is configured in the same manner as the metal saw clamp groove described above, and includes a main seat surface (lower jaw) 3a, a pressing portion (upper jaw) 3b having a pressing surface 3d, and a sub-seat surface 3c. Have In addition, the inner end of the clamp groove 3 has a relief portion 6 connected to the clamp groove 3, and the slit 7 opened in the relief portion 6 is further away from the clamp groove 3 than the pressing surface 3 d of the pressing portion 3 b. It is formed along the pressing surface 3d at the position.

  The chip 20 used for the cutting tool may be provided with a protrusion or the like serving as a chip breaker on the rake face 22 as necessary, but the basic configuration is not much different from the chip of FIG.

9 is also slit from the inner end of the pressing portion 3b when a situation occurs in which the pressing surface 3d is pressed only on the back end side of the clamping groove 3 against the chip 20 press-fitted into the clamping groove 3. The portion up to the outer end of 7 is elastically deformed in the direction in which the mouth of the slit 7 is closed, so that the contact area of the pressing portion 3b with respect to the chip 20 is expanded and the stability of the clamp is increased. In addition, since this cutting tool 30 can adjust the elastic restoring force of the press part 3b by changing the dimension from the thinning part 6 to the upper edge of the tool main body 2, the 2nd slit is unnecessary.

An end view showing an example of a blade-tip replaceable metal saw to which the present invention is applied Side view showing a part of the metal saw of FIG. Enlarged end view of a part of the tool body of the metal saw of FIG. Enlarged end view of a part of the tool body of the metal saw of FIG. End view of part of metal saw with deformed second slit Enlarged end view of a part of the tool body of the metal saw in FIG. End view of a part of a metal saw with a clamp screw for assisting the pressing force 1 is a perspective view of a chip employed in the metal saw of FIGS. Side view of a tool to which the present invention is applied

DESCRIPTION OF SYMBOLS 1 Cutting edge replaceable metal saw 2 Tool body 3 Clamp groove 3a Main seat surface 3b Press part 3c Sub seat surface 3d Press surface 4 Shaft hole 5 Chip pocket 6 Slack part 7 Slit 8 Second slit 9 Screw hole 10 Clamp screw 10a Taper head Part 11 Joint part 20 Tip 21 Cutting edge 22 Rake face 23 Relief face 24 Front face 25 Rear face 26 End face 30 Bit

Claims (6)

Clamping groove comprising a cutting edge tip (20), a main seating surface (3a) for supporting the back surface (25) of the cutting edge tip, and an elastically deformable pressing portion (3b) opposed to the main seating surface ( 3) and a pressing tool (3b) for generating a pressing force by elastic recovery of the cutting edge tip (20) and the main seating surface (3a) of the clamp groove. A self-clamp cutting tool with a replaceable blade tip that is sandwiched between and fixed,
A slit (opened in the tool main body (2) toward the base thin portion (6) of the pressing portion (3b) so that the inner end side of the pressing portion (3b) can be elastically deformed in the slit width direction. 7) is formed so as to be along the pressing surface (3d) at a position farther from the clamping groove (3) than the pressing surface (3d) of the pressing portion (3b). Cutting tools.   The clamp groove (3) is inclined with respect to the main seat surface (3a) by an angle α in the direction in which the pressing surface (3d) of the pressing portion (3b) widens on the entrance side of the clamp groove (3). The blade-tip replaceable self-clamp cutting tool according to claim 1, wherein the tool is a groove.   The clamp groove (3), the slit (7), and the chip pocket (5) corresponding to each clamp groove (3) are provided on the outer periphery of the plate-shaped tool body (2) that is mounted on the drive shaft and rotated. The blade-tip-exchangeable self-clamp cutting tool according to claim 1 or 2, wherein a plurality of blade-tip-exchangeable metal saws (1) are provided at intervals in the circumferential direction.   A second slit (8) having an outer end opened in the chip pocket (5) and an inner end inward of the pressing portion (3b) in the radial direction is provided on the tool body (from the slit (7)). 2) is further provided in front of the rotation direction, and the pressing portion (3b) is connected to the tool main body (11) remaining between the clamp groove (3) and the second slit (8). The blade edge replaceable self-clamp cutting tool according to claim 3, wherein the tool can be elastically deformed as a fulcrum. The second slit (8) is an arc slit having a center on the clamp groove (3) side, or an angle γ in a direction in which the inner end side is separated from the main seat surface with respect to the main seat surface (3a). The blade-tip-exchange-type self-clamp cutting tool according to claim 4, wherein the slit has an inclination of 5 mm.   A clamp screw (10) is pressed into the portion where the second slit (8) is formed toward the center of the tool body (2) and pushes the pressing portion (3b) in a direction in which the pressing portion is elastically restored. The blade-tip replaceable self-clamp cutting tool according to claim 4 further provided.

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