JPH077061Y2 - Throw-away tip for thread cutter - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a throw-away tip for a thread cutting cutter that performs thread cutting by rolling.

"Prior Art" As throw-away chips of this type, those shown in Figs. 5 and 6 are known. This conventional chip 1
Has a trapezoidal flat plate shape in which the upper surface 2 and the lower surface 3 are parallel to each other, and one of the upper surface 2 and the lower surface 3 serves as a seating surface and the other serves as a rake surface (in FIG. 6, the lower surface). 3 is a seating surface and the upper surface 2 is a rake surface), the side surface 4 is a flank surface, the upper surface 2 and the lower surface 3
The cutting edges 5 and 5 for threading are formed at the cross edges of
Further, rake grooves 6, 6 are formed in the peripheral portions of the upper surface 2 and the lower surface 3 along the cutting edges 5, 5, respectively.
The tip 1 has its seating surface closely attached to the mounting bottom surface 9 of the tip mounting seat 8 provided at the tip of the cutter body 7, and is inclined with respect to the side surface 4 which is the flank surface. The two side faces 10, 10 of the chip mounting seat 8
Each of them is positioned and fixed by a clamp screw 12 in a state where they are brought into close contact with each other.

[Problems to be solved by the invention] By the way, the conventional chip 1 having a trapezoidal shape as described above.
Then, since the two side surfaces 10, 10 inclined with respect to the side surface 4 which is the flank are brought into close contact with the mounting side surfaces 11, 11 of the chip mounting seat 8 for positioning, the chip mounting seat 8 However, the machining error of 1 has a great influence on the positioning accuracy of the chip 1. That is, for example, as shown in FIG. 5, the positions of the mounting side surfaces 11, 11 of the chip mounting seat 8 are machined so as to deviate from the normal position by an error dimension δ,
When the side surfaces 10 and 10 of the chip 1 are closely contacted with the chips 11 and 11 for positioning, the displacement dimension δ ′ of the chip 1 from the normal position
Depends on the inclination angles of the side surfaces 10, 10, 11, 11 but reaches about twice the error dimension δ. For this reason, even if the above-mentioned error dimension δ is a small value that is originally allowable, the displacement dimension δ ′ of the chip 1 is enlarged to a non-negligible level. There is a possibility that a thread cutting cutter using may not always obtain sufficient processing accuracy. This is exactly the same not only when there is a processing error in the chip mounting seat 8, but also when there is an error in the dimensions of the chip 1 itself.

Further, in the above-mentioned tip 1, rake grooves 6 and 6 are formed on the upper surface 2 and the lower surface 3 along the cutting edges 5 and 5, respectively, and these rake grooves 6 and 6 are closely attached to the mounting bottom surface 9 of the chip mounting seat 8. Therefore, as shown in FIG. 6, the overhang amount h of the tip 1 becomes too large, so that not only the tip damage such as chipping of the cutting edges 5 and 5 is likely to occur, but also the cutting edge during cutting. The cutting force F applied to the portion cannot be sufficiently received by the mounting bottom surface 9 of the tip mounting seat 8, which is disadvantageous in securing the rigidity and stability of the clamp.

The present invention has been made in view of the above circumstances, and provides a throw-away tip for a thread cutting cutter capable of positioning the tip with high precision and ensuring sufficient rigidity and stability of the clamp. The purpose is to do.

[Means for Solving the Problem] The present invention is mounted on a tip mounting seat provided at the tip of a cylindrical cutter body, and a mounting bottom surface facing the tip side of the cutter body of the chip mounting seat, and a mounting bottom surface thereof. In a throw-away tip for a thread cutting cutter that is positioned and fixed by two mounting side surfaces that are continuous with each other, the upper surface and the lower surface are in a substantially rectangular parallelepiped flat plate shape, and the side surfaces at opposite positions are mutually In addition to being parallel, a cutting edge for thread cutting that forms a mountain shape is formed at the crossing edge of the adjacent side surfaces, and the upper surface or the lower surface is used as a seating surface to closely adhere to the mounting bottom surface of the chip mounting seat and the side surface. The two side surfaces adjacent to each other are closely positioned to the mounting side surfaces of the chip mounting seat, respectively, so that they are positioned and fixed. One of the two side surfaces having the cutting edge as the crossing edge has a flank surface formed along the cutting edge, and the other side surface is formed with a rake surface along the cutting edge, and A flat surface is formed on the side opposite to the cutting edge of the flank so that it can be brought into close contact with the mounting side surface of the tip mounting seat, and the flank is formed by the cutting edge as it is separated from the cutting edge side. It is characterized in that it is formed so as to become gradually wider with the tip end of the chevron as the apex, is continuous with the flat surface, and can be adhered to the mounting side surface of the chip mounting seat together with the flat surface.

[Operation] The throw-away tip of the present invention has a lower surface as a seating surface and is closely attached to the mounting bottom surface of the chip mounting seat, and two adjacent side surfaces of the tip mounting surface are closely adhered to the mounting side surface of the chip mounting seat, respectively. Accurate positioning is naturally performed, and the cutting force applied during cutting is received by the entire peripheral edge along one side of the throw-away tip to secure sufficient clamp rigidity.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a front view showing a state in which the throw-away tip 20 of this embodiment is mounted on a tip mounting seat 22 provided at the tip of a cutter body 21, and FIG. 2 is a side view thereof.
The cutter body 21 has a columnar shape, and the tip mounting seat 22 provided at the tip of the cutter body 21.
Has a mounting bottom surface 23 facing the tip side of the cutter body 21, and two mounting side surfaces 24, 24 continuous with the mounting bottom surface 23.

The throw-away tip 20 of the present embodiment has a square plate-like appearance in which the upper surface 25 and the lower surface 26 are parallel to each other, and the side surfaces at opposing positions are parallel to each other, and is adjacent to one of the four side surfaces. The cutting edges 27 for thread cutting are respectively formed on the intersecting edges of the side surfaces that are formed, and these cutting edges 27 are formed in a mountain shape that matches the shape of the screw to be formed.

Further, on the side surfaces between the cutting edges 27, 27 adjacent to each other, a flank 28 along the one cutting edge 27 is formed, and a rake surface 29 along the other cutting edge 27 is formed, and A flat surface 30 is formed between the flank surface 28 and the rake surface 29 so as to be in close contact with the mounting side surface 24 of the tip mounting seat 22. The flank surface 28 is continuous with the flat surface 30 as shown in FIG. 3, and gradually widens as it is separated from the cutting edge 27 side with the chevron-shaped tip of the cutting edge 27 as the apex. Thus, the flat surface 30 is formed in the shape of a triangular flat surface. In addition, this flank 28 is a cutting edge
27 has a groove portion 31 corresponding to the chevron shape (that is, the shape of the screw to be formed), and the groove portion
The depth of 31 is gradually reduced from the cutting edge 27 toward the flat surface 30.

Further, the flank 28 is, as shown in FIG.
It is composed of a first flank 28a along with 27 and a second flank 28b having a larger flank angle than the first flank 28a on the rear side in the rotation direction of the first flank 28a, thereby strengthening the cutting edge portion. As a result, chipping and defects are less likely to occur. The cutting edge angle θ may be set as appropriate, but generally, it is good to set it to about 60 ° to 80 °. The first flank 28
The range forming a, that is, the dimension 1 in FIG.
It is good to set it to about 1.0 mm. This is because if it is 0.1 mm or less, the cutting edge portion cannot be sufficiently strengthened, and if it exceeds 1.0 mm, the first flank 28a may come into contact with the cutting surface, so-called second hit.

The throw-away tip having the above-described structure is in close contact with the mounting bottom surface 23 of the tip mounting seat 22 with the lower surface 26 as the seating surface, and the two side surfaces adjacent to each other among the side surfaces are the mounting side surfaces 24 of the chip mounting seat 22, respectively. It is positioned by being brought into close contact with 24, and is fixed to the chip mounting seat 22 by a clamp screw 32 in a state where it is placed on a so-called vertical blade.

Since the throw-away tip 20 has the four cutting edges 27, it is of course economical to use these cutting edges 27 ... The throw-away tip 20 has the lower surface 26 as a seating surface and is brought into close contact with the mounting bottom surface 23 of the chip mounting seat 22, and the flanks 28, 28 and the flat surfaces 30, 30 formed on the side surfaces are mounting side surfaces of the chip mounting seat 22. Since they are positioned in close contact with 24, 24, even if a processing error of the chip mounting seat 22 or a dimensional error of the chip 20 itself occurs, the positional displacement of the chip 20 is limited to the magnitude of the error, and therefore,
As in the case of the conventional trapezoidal chip, the positional deviation does not become larger than the processing error of the mounting seat 22 or the chip size error.

In addition, since this throw-away tip 20 is clamped in a so-called vertically placed state, the tip 20
The main component force of the cutting force F applied to is to be received by the entire peripheral portion along one side of the tip 20, but the length dimension of that side is sufficiently larger than the thickness dimension of the conventional tip 1. Moreover, since the flank surface 28 and the flat surface 30 formed on the side surface of the tip 20 are in close contact with the mounting side surface 24 of the mounting seat 22, the cutting force F is also received by the mounting side surface 24. Therefore, this chip 20 can secure sufficient clamp rigidity as compared with the conventional chip 1 in which a large overhang occurs.

Although the throw-away tip of the above-described embodiment has a square plate-like appearance, the same effect can be obtained if the side surfaces at the facing positions are parallel to each other, and therefore, more generally, a rhombus shape. Any parallelogram plate shape including a rectangular shape and a rectangular shape may be used. Further, in the above-described embodiment, the cutting edges are provided on all the cross edges of the side surfaces, but the number of cutting edges is not necessarily limited to four, but may be limited to two, for example.

[Advantage of Invention] As described in detail above, the throw-away tip of the present invention has a rectangular flat plate-like appearance, and the cutting edges for threading are formed on the cross edges of the adjacent side surfaces. Since the side surface has a flat surface that can be in close contact with the mounting side surface of the chip mounting seat and a flank that is continuous with it, the lower surface is used as the seating surface and is in close contact with the mounting bottom surface of the chip mounting seat and is formed on the side surface. By accurately adhering the above-mentioned flat surface and flank surface to the mounting side surface of the chip mounting seat, accurate positioning is naturally performed, and therefore, the positioning accuracy can be improved as compared with the conventional trapezoidal chip. At the same time, there is an effect that sufficient clamp rigidity can be secured.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
FIG. 1 is a front view showing a state where the throw-away tip of this embodiment is attached to a cutter body, FIG. 2 is a side view (partially sectional view) thereof, and FIG. 3 is a III-III line of FIG. FIG. 4 is an enlarged view of the IV section in FIG. FIG. 5 is a side view showing a state in which a conventional throw-away tip is attached to a cutter body, and FIG. 6 is a sectional view thereof. 20 …… Throw-away tip, 21 …… Cutter body, 22
…… Chip mounting seat, 23 …… Mounting bottom, 24 …… Mounting side,
25 …… upper surface, 26 …… lower surface, 27 …… cutting edge, 28 …… flank surface,
28a ... 1st flank, 28b ... 2nd flank, 29 ... rake face, 30 ... flat surface, 31 ... groove part, 32 ... clamp screw.

Claims (1)

[Scope of utility model registration request] 1. A mounting bottom face which is mounted on a tip mounting seat provided at the tip of a cylindrical cutter body and faces the tip side of the cutter body of the tip mounting seat, and two mountings which are continuous to the mounting bottom face. In a throw-away tip for a thread cutting cutter that is positioned and fixed by the side surface, the upper surface and the lower surface have a substantially rectangular parallelepiped shape, and the side surfaces at opposite positions are parallel to each other and are adjacent to each other. Forming a chevron-shaped cutting edge at the crossing edge of the side surfaces that are in contact with each other, and the upper surface or the lower surface is used as a seating surface to closely adhere to the mounting bottom surface of the chip mounting seat, and two adjacent side surfaces of the side surfaces. Are configured to be positioned and fixed by closely adhering to the mounting side surface of the tip mounting seat, and two side surfaces having the cutting edges as cross edges One of the side surfaces is formed with a flank to follow the cutting edge, and the other side is formed with a rake face to follow the cutting edge, and the flank is opposite to the cutting edge. Is formed with a flat surface that can be brought into close contact with the mounting side surface of the tip mounting seat, and the flank surface gradually widens as the tip of the chevron formed by the cutting edge becomes an apex as it separates from the cutting edge side. A throw-away tip for a thread cutting cutter, characterized in that it is formed so as to be continuous with the flat surface and can be brought into close contact with the mounting side surface of the tip mounting seat together with the flat surface.