JP6253093B2 - Cutting insert and cutting edge exchangeable cutting tool - Google Patents

Description

  The present invention realizes a space saving of the clamping mechanism using the cutting insert that can be firmly fixed to the tool body by a clamping mechanism that can contribute to the increase in the number of cutting tools, and further provided on the tool body. The present invention relates to a cutting edge exchangeable cutting tool that relaxes the processing restriction of a screw hole for clamping a screw.

  A clamp mechanism for fixing a cutting insert, which is employed in a cutting edge exchangeable cutting tool such as a cutting edge exchangeable milling cutter, is generally a screw clamp type.

  The clamp mechanism of the screw clamp system passes the clamp screw through a mounting hole provided in the cutting insert, and fastens the clamp screw to fix the cutting insert.

  Cutting inserts mounted on the tool body by the screw clamp type clamping mechanism are arranged horizontally as shown in the following Patent Document 1 (see FIG. 16) and vertically arranged as shown in the following Patent Document 2 (see FIG. (See FIG. 17). 16 and 17 is a cutting insert, and a clamping screw (not shown) to be screwed into the tool body 2 is passed through an attachment hole (also not shown) provided at the center.

  In Patent Document 3 below, a cutting insert without a mounting hole is mounted horizontally in a blade groove on the outer periphery of the tool body, and the upper surface of the cutting insert is pressed by a taper head provided on a clamp screw. A cutting insert mounting structure is disclosed.

JP 2006-167913 A JP 2007-125669 A Japanese Utility Model Publication No. 6-74204

  As for the cutting tool in which the cutting insert is placed horizontally as in Patent Document 1, it is necessary to process a screw hole for screwing a clamp screw provided in the tool body from the front in the rotational direction of the tool, and the rake face of the cutting insert The processing space to be secured above is increased.

  Since many tool bodies are shaved to secure the processing space, it is difficult to increase the number of blades of the tool.

  In addition, if the screw hole is long, there is a possibility that the screw hole penetrates to the outer periphery of the tool body, and the processing difficulty of the screw hole is high.

  On the other hand, since the cutting tool in which the cutting insert is placed vertically as in Patent Document 2 processes a screw hole from the outer peripheral side of the tool body toward the radial inner side, the processing of the screw hole is performed. Difficulty goes down. However, in this cutting tool, the circumferential space of the tool body occupied by one cutting insert becomes large due to the vertical placement of the cutting insert. Accordingly, even with this structure, it is difficult to increase the number of tools.

In the mounting structure described in Patent Document 3, the clamp screw is screwed from the outer peripheral side to the center side of the tool main body, although the cutting insert is disposed horizontally. for that reason,
There is an advantage that the number of cutting tools can be increased.

  However, in the mounting structure of Patent Document 3, the cutting insert is pressed by the clamp screw in a region far from the cutting edge involved in cutting (on the side opposite to the cutting edge than the center of the upper surface). May become unstable and the blade edge may be lifted from the seat bottom (mounting surface) of the blade groove.

  This invention makes it the subject to enable the firm fixation of a cutting insert, making use of the characteristic of the attachment structure of patent document 3. FIG.

As a solution to the above problem, the present invention provides a cutting insert of the following 1) and a cutting edge exchangeable cutting tool of the following 2) using the cutting insert.
1) A cutting insert having a clamped surface that is pressed by a clamp screw, wherein the clamped surface has a concave conical shape that is inclined in a direction in which the position increases as the distance from the ridge line on the outer periphery of the upper surface or lower surface increases toward the center of the insert. Cutting inserts that are made up of slopes.
2) A tool body having a blade groove and a chip pocket facing the blade groove, a cutting insert having a clamped surface formed by a concave conical slope on the upper surface or the lower surface, and mounted in the blade groove; A cutting edge replaceable cutting tool having a clamp screw that is screwed into the tool body and fixes the cutting insert, wherein the clamp screw has a tapered head with a large diameter at the top of the head, and an outer periphery of the head The blade surface is exchanged by pressing the surface to be clamped with a taper surface, and the pressing is performed on the surface to be clamped on the side of the cutting edge involved in cutting from the center of the cutting insert set in the blade groove. Type cutting tool.

  The cutting insert of this invention can eliminate the concern that the cutting edge is lifted from the seat bottom.

  The cutting edge replacement type cutting tool of the present invention using the cutting insert is relaxed in the restriction of multiple blades, and does not increase the difficulty of processing a screw hole.

  Further, the stability of fixing of the cutting insert is increased as compared with the one having the mounting structure of Patent Document 3.

It is a perspective view which shows an example of the cutting insert of this invention. It is a top view of the cutting insert of FIG. It is a side view of the cutting insert of FIG. It is a top view which shows the other example of the cutting insert of this invention. It is a top view which shows the further another example of the cutting insert of this invention. It is a bottom view of the cutting insert of FIG. It is a side view of the cutting insert of FIG. It is a top view which shows the further another example of the cutting insert of this invention. It is a side view which shows an example of the blade-tip-exchange-type cutting tool of this invention. It is a front view of the blade-tip-exchange-type cutting tool of FIG. It is a side view of the tool main body of the blade-tip-exchange-type cutting tool of FIG. It is a front view of the tool main body of the blade-tip-exchange-type cutting tool of FIG. It is an expanded sectional view of the position along the AA line of FIG. It is a side view which shows the other example of the blade-tip-exchange-type cutting tool of this invention. It is a front view of the blade-tip-exchange-type cutting tool of FIG. It is a front view of the conventional cutting tool which set the cutting insert horizontally. It is a front view of the conventional cutting tool which set the cutting insert vertically.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a cutting insert and a blade-tip-exchangeable cutting tool according to the present invention will be described below with reference to FIGS.

  One form of the cutting insert of this invention is shown in FIGS. The illustrated cutting insert 1 is a positive-type insert having a square shape with a side surface 3 intersecting at an acute angle with respect to the upper surface 2 and having no mounting holes. The lower surface 4 is seated on the seat bottom surface of the blade groove in a lateral orientation. The upper surface 2 is used as a rake face.

  The ridge line on the outer periphery of the upper surface 2 (the ridge line at the intersection with the side surface 3) constitutes the cutting edge 5. The cutting edge 5 includes a straight main cutting edge 5a disposed between adjacent corners and a corner cutting edge 5b having a predetermined R radius.

  A clamped surface 6 that is pressed by a clamp screw is provided on the upper surface 2.

  The clamped surface 6 is constituted by a concave conical slope inclined in a direction in which the position becomes higher as it moves away from the main cutting edge 5a toward the center of the insert.

  The clamped surface 6 may be a concave conical surface having a larger radius of curvature than the head of the clamp screw, which will be described later, and the head of the clamp screw may be in line contact with the bottom of the recess. It is preferable that the taper surface of the head of the clamp screw is in wide surface contact with the surface to be clamped corresponding to the head diameter.

  According to the structure, the fixing force can be widely dispersed and applied in a well-balanced manner without applying a tensile stress to the cutting insert.

  The to-be-clamped surface 6 is arranged so as to be centered on a line that crosses the longitudinal intermediate point of each main cutting edge 5a at a right angle in plan view, corresponding to each of the main cutting edges 5a. Further, the number of the clamped surfaces 6 is the same as the number of corners, and all of the plural cutting edges can be used effectively. In addition, the upper surface 2 on which the clamped surface 6 is installed has a raised central portion, and the strength of the cutting insert can be increased as compared with a non-swelled one.

  In addition, although FIGS. 1-3 is a planar-view square cutting insert, this invention is a rectangle provided with two main cutting edges of parallel arrangement, a parallelogram, a regular triangle provided with three main cutting edges, etc. The present invention can also be applied to polygonal cutting inserts other than a square or a circular cutting insert in plan view shown in FIG.

  In the cutting insert having a circular shape in plan view, the ridgeline that becomes the main cutting edge 5a has a circular shape. As shown in the figure, the used blade and the unused blade can be exchanged at a predetermined index angle by arranging the center of the clamped surface 6 on the line connecting the circumferential equal dividing point of the circular ridge line and the center of the insert. .

  5 to 7, a clamped surface 6 constituted by a concave conical slope is provided on the lower surface 4 of the cutting insert 1. The cutting insert may be fixed by pressing the lower surface of the cutting insert toward the front in the rotational direction of the cutting tool and pressing the upper surface serving as the rake face of the cutting insert against the seat bottom of the blade groove.

  The clamp-type cutting insert has a clamped surface 6 on the lower surface 4 as shown in FIGS. The location of the clamped surface 6 on the lower surface 4 is set in the same manner as that for providing the clamped surface on the upper surface.

  The cutting insert 1 of FIG. 8 has a clamped surface 6 provided on a bisector of a corner angle of each corner of the upper surface 2. The clamped surface 6 is composed of a concave conical slope inclined in a direction in which the position becomes higher as it goes away from the corner cutting edge 5b toward the center of the insert.

  Thus, the center of the clamped surface 6 may be disposed on a line that is oblique to the straight main cutting edge 5a. It is conceivable that the cutting insert 1 of this form also has the clamped surface 6 on the lower surface.

  Next, specific examples of the cutting edge-exchangeable cutting tool of the present invention will be described with reference to FIGS. 9 to 15 of the attached drawings.

  The cutting edge exchange type cutting tool of FIGS. 9-13 uses the cutting insert which provided the to-be-clamped surface on the upper surface.

  This blade-tip-exchangeable cutting tool 10 includes a tool main body 11, a cutting insert 1, and a clamp screw 15 that fixes the cutting insert 1 to the tool main body 11.

  The tool body 11 has a blade groove 12 having a seat bottom surface and a seat side surface on the outer periphery of the tip. Moreover, it has the chip pocket 13 made to face each of the blade groove | channel 12 provided with two or more with the constant pitch in the circumferential direction.

  The cutting insert 1 is incorporated in each blade groove 12 in a horizontally arranged manner. The cutting insert 1 is shown in FIGS. 1 to 3 and has a clamped surface 6 formed of a concave conical slope on the upper surface 2.

  The cutting insert 1 of FIGS. 1-3 is provided with four to-be-clamped surfaces 6 corresponding to each of the four main cutting edges 5a (refer FIG. 1, FIG. 2) as already stated.

  The clamped surface 6 has a center on a line that crosses the longitudinal middle point of each main cutting edge at a right angle in plan view. Therefore, the screw 15 is screwed into the screw hole 14 (see FIGS. 11 and 13) provided in the tool body 11 from the outer peripheral side of the tool body 11 toward the radially inner side.

  As shown in FIG. 13, the clamp screw 15 has a tapered head portion 15 a (see FIG. 13) with a large diameter at the top (tip). The taper surface on the outer periphery of the head of the clamp screw 15 contacts the clamped surface 6 of the cutting insert 1 set in each blade groove 12 and presses the clamped surface 6.

  The pressing is performed on the clamped surface on the side of the cutting edge involved in cutting with respect to the center portion of the cutting insert 1. Thereby, the cutting insert 1 is pressed against the seat bottom surface 12a and the seat side surface 12b (also see FIG. 13) of the blade groove 12.

  The pressing of the cutting insert 1 against the seat bottom at this time is strongly performed on the main cutting edge side involved in cutting.

  In addition to this, since the clamped surface 6 is an inclined surface, the clamping screw 15 is also pressed against the seat side surface 12b in the screwing direction front (also see FIG. 13), which is disclosed in the above-mentioned Patent Document 3. Compared to the mounting structure, the stability of fixing is increased, and damage to the cutting edge due to unstable clamping and machining troubles due to the displacement of the cutting edge are surely prevented.

  Note that, as described above, the cutting insert in FIG. 8 is inclined in a direction in which the clamped surface 6 is arranged on a bisector of the corner angle of the upper surface and becomes higher as it moves away from the corner toward the center.

  Therefore, in the cutting edge exchange type cutting tool using the cutting insert having the clamped surface 6 provided at the position, the screwing direction of the clamp screw 15 is directed radially inward and obliquely rearward, so that the cutting insert is pressed. This is done with respect to three surfaces of two seating side surfaces whose directions are 90 ° different from each other.

  Also in this case, the cutting insert can be firmly and stably fixed by pressing the clamped surface 6 by the clamp screw 15 on the clamped surface 6 on the corner cutting edge side involved in cutting. Can do. The screwing direction of the clamp screw 15 is not limited to the radially inner side, and may be a direction along the rotation center axis of the tool from the tip side of the tool body.

  14A and 15B uses a cutting insert having a clamped surface on the lower surface.

  In this embodiment, the flat land 2 a provided on the upper surface 2 of the cutting insert 1 is pressed against the seat bottom surface of the blade groove 12. Even in this structure, the clamped surface 15 is pressed by the clamp screw 15 on the side of the cutting edge involved in cutting, so that it can be firmly fixed as in the case of pressing the clamped surface on the upper surface.

  The clamped surface 6 provided on the upper or lower surface of the cutting insert has a wedge effect if the height h (see FIGS. 3 and 7) between the upper and lower surfaces of the slope is 0.5 mm, and the head of the clamp screw. However, for more effective and stable pressing, the height h is preferably secured to 1/4 or more of the head diameter of the clamp screw 15.

  Further, the height h is preferably ½ or less of the head diameter of the clamp screw 15 in order to avoid unnecessary increase in the thickness of the cutting insert.

1, 1A Cutting insert 2 Upper surface 2a Flat land 3 Side surface 4 Lower surface 5 Cutting edge 5a Main cutting edge 5b Corner cutting edge 6 Clamped surface 10, 10A Cutting edge exchangeable cutting tool 11 Tool body 12 Blade groove 12a Seat bottom surface 12b Seat side surface 13 Chip pocket 14 Screw hole 15 Clamp screw 15a Head

Claims (4)

A cutting insert having a clamped surface to be pressed by a clamp screw, wherein the cutting insert is a polygon in plan view, and a plurality of the clamped surfaces are provided on an upper surface or a lower surface, and the clamped surface is an upper surface or a lower surface It is composed of a concave conical slope inclined in a direction where the position becomes higher as it goes away from the ridge line of the outer periphery of the insert toward the center of the insert ,
The ridge line is a main cutting edge, and the ridge line is a straight ridge line disposed between adjacent corners, and the center of the clamped surface is on a line perpendicular to the longitudinal midpoint of the straight ridge line in a plan view. Is a cutting insert in which the center part of the surface on the side where the inclined surface is installed is provided with the same number of clamped surfaces as the number of corners . A cutting insert having a clamped surface to be pressed by a clamp screw, wherein the clamped surface has a concave conical slope inclined in a direction of increasing the position as the clamped surface moves away from the ridge line on the outer periphery of the upper surface or the lower surface toward the center of the insert. Consists of
The ridgeline of the cutting insert is a corner cutting edge, the cutting insert clamped surface is provided on bisector of the corner angle of the upper surface or lower surface of the corner. The claim 2 clamped surface is raised central portion of the surface of the corner count by placing a center bisector same number provided by the side which is placed the clamped surface of the corner angle of the corner Cutting inserts. A tool body having a blade groove and a chip pocket facing the blade groove, a cutting insert having a clamped surface formed by a concave conical inclined surface on the upper surface or the lower surface, and mounted in the blade groove, and the tool A cutting edge replaceable cutting tool provided with a clamp screw that is screwed into a main body to fix the cutting insert, the clamp screw having a tapered head with a large diameter at the top of the head,
The cutting edge that presses the clamped surface formed by the concave conical slope with the tapered surface of the outer periphery of the head, and the pressing is more involved in cutting than the central part of the cutting insert set in the blade groove Be done on the clamped surface on the side ,
A cutting edge-exchangeable cutting tool in which a rising amount of the surface on which the clamped surface of the cutting insert is set is set to ¼ or more of a head diameter of the clamp screw .

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