JPH077062Y2 - Throw-away tip for thread cutting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a throw-away tip for thread cutting.

"Prior Art" As a throw-away tip (hereinafter simply referred to as a tip) for thread cutting, those shown in FIGS. 8 and 9 have been conventionally known. This is a substantially triangular plate-like appearance, and the convex portions 1 are formed at the respective corner portions, and the concave portions 2 and 3 are continuously formed on both sides of the convex portions 1. It has become a thing. Then, the cutting edges 4 for threading are formed on the ridges on the upper surface side of the convex portion 1, respectively, and the upper surface and the side surfaces along with the cutting edges 4 are the rake surface 5 and the flank surface 6, respectively, and the flat lower surface is This is the seating surface 7.

As shown in FIGS. 10 and 11, the above-described conventional tip is used by being attached to a holder 8 with one of the cutting blades 4 slightly protruding to the outer peripheral side. In the case of performing internal thread processing, the holder 8 is fed into the prepared hole 10 formed in advance in the work 9 while rotating the holder 8 (or while rotating the work 9). The inner surface of 10 is threaded.

[Problems to be solved by the invention] By the way, when the above-mentioned conventional insert is used to perform the female threading as described above, the threading is performed inside the prepared hole 10 of the workpiece 9, so that the chips are discharged to the outside. It is difficult to do so, and as shown in FIG. 12, the chips 11 wrap around to the lower surface 7 side of the chip and collide violently with the lower surface 7, resulting in chipping of the flank surface 6 on the lower surface 7 side as shown in FIG. Could occur. Then, when such a defect occurs, the strength of the cutting edge portion is greatly reduced, so that the cutting edge 4 is damaged early as shown in FIG. It had the drawback of being short.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a throw-away tip for thread cutting, which can effectively prevent the cutting edge from being damaged.

"Means for Solving the Problem" The present invention has at least one cutting edge for thread cutting formed on the ridge portion of the upper surface to be a rake surface, the side surface along the cutting edge is a flank, and the lower surface is In a plate-shaped threading insert for a seating surface, a chamfer having a width of 0.3 mm to 1.0 mm in a direction along the flank and the seating surface at a crossing ridge portion between the flank and the seating surface. It is characterized by being applied.

[Operation] In the chip of the present invention, the chip-impacting surface is chamfered on the lower surface side of the flank where chips are likely to collide, resulting in improved chipping resistance of the chip and, as a result, cutting edge. The strength of the portion is secured for a long period of time, and the cutting edge is prevented from being damaged early.

Here, the width in the direction along the flank of the chamfer, or the width in the direction along the seating surface, that is, the lower surface, is smaller than 0.3 mm, there is a possibility that the above effect may not be obtained, conversely 1.0 mm If it exceeds the limit, the fracture resistance of the ridge line intersecting the flank and the seating surface is improved, but the wall thickness of the tip in the direction directly below the cutting edge is impaired, especially for the main component force acting on the cutting edge. As a result, there is a possibility that sufficient chip rigidity cannot be secured.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. Since the chip of this embodiment is based on the conventional chip described above, The same parts as the chip of FIG.

In the chip of the present embodiment, the chamfering 20 is applied to the lower surface 7, the flank 6 (that is, the side surface of the convex portion 1) and the intersecting ridges of the side surfaces of the concave portions 2 and 3 formed continuously on both sides thereof. It has been done. The range in which the chamfer 20 is applied, that is, the width of the chamfer 20 shown in FIG.
The width d2 in the direction along the d1 and the lower surface (seat surface) 7 is set in the range of 0.3 mm to 0.3 mm in this embodiment.

By the chamfering 20 as described above, this chip is provided with the cutting edge 4 by the chips 11 when the internal thread processing is performed.
It is possible to effectively prevent the loss of. That is, when this tip is mounted on the tip of the holder 8 in the same manner as in the conventional case and the internal thread processing is performed as shown in FIG. 6, the chips 11 are the same as in the conventional case. Although it is unavoidable that it will go around to the 7 side and collide with the lower surface 7 of the chip, this chip has chamfered 20 so that the chipping resistance performance of the part that was easy to chip in the past is greatly improved. Therefore, even if the chips 11 collide with each other, a defect as shown in FIG. 13 does not occur.

Therefore, in this tip, the strength of the cutting edge portion does not decrease due to a defect on the lower surface 7 side of the flank 6 as in the conventional case, and as a result, the cutting edge 4 may be damaged early. It is effectively prevented and the chip can have a significantly longer life.

In the chip of the above-mentioned embodiment, not only the flank 6 or the crossing ridge of the side surface of the convex portion 1 and the lower surface 7 but also the side ridges of the concave portions 2 and 3 formed on both sides of the convex portion 1 and the crossing ridge portion of the lower surface 7 are formed. However, the chamfering 20 is not necessarily required to be continuous, but the chamfering 20 may be performed only on the intersecting ridge line portion between the flank 6 and the lower surface 7 as shown in FIG. 7, for example.
In this case as well, the size of the chamfer 20 may be set appropriately, but it is desirable to make it slightly larger than in the case of the above embodiment. In this embodiment, the widths corresponding to the widths d1 and d2 in FIG. Both are set to 1.0 mm. Further, both the chamfer as shown in FIG. 7 and the chamfer as shown in FIG. 4 are provided, that is, at the ridge portion where the flank 6 and the lower surface 7 intersect each other, as shown in FIG. If the chamfering is performed and the ridge line portion where the side surfaces of the recesses 2 and 3 and the lower surface 7 intersect is chamfered as shown in FIG. 4, the above effect can be further enhanced.

Regarding the size of the chamfer 20, in the embodiment shown in FIG. 5, the widths d1 and d2 in the direction along the flank 6 and the lower surface 7 of the chamfer 20 are both in the range of 0.1 mm to 0.7 mm, In the embodiment shown in FIG. 7, the widths d1 and d2 are 1.0
However, this is because the width d1, d2 of these chamfers 20 is too small, the above-described defect prevention effect by applying the chamfers 20 may not be sufficiently exerted,
On the other hand, if the widths d1 and d2 are too large, the wall thickness of the convex portion 1 of the chip is cut in the direction directly below the cutting edge 4, and therefore the largest main component force among the cutting forces acting on the cutting edge 4 is generated. This is because there is a possibility that sufficient chip rigidity cannot be ensured. Therefore, the size of the chamfer 20 should be set so that the widths d1 and d2 are both in the range of 0.3 mm to 1.0 mm.

Further, in the above-mentioned embodiment, the appearance of the tip is made into a triangular flat plate shape and the convex portions 1 and the concave portions 2 and 3 are provided at each corner thereof, but the shape of the tip and the number of cutting edges are arbitrary, The recesses 2 and 3 may be omitted if unnecessary.

Further, it goes without saying that the tip of the present invention can be used not only for female thread processing but also for male thread processing.

"Effect of the device" As described in detail above, the throw-away tip of the present invention is chamfered at the ridge line intersecting the flank and the seating surface, so that it was a part that was easily damaged in the past. The fracture resistance performance of the lower surface side portion of the surface is greatly improved, and as a result, the strength of the cutting edge portion is not reduced and the cutting edge is effectively prevented from being damaged early.
It has an excellent effect.

Moreover, since the size of this chamfer is set so that the width in the direction along the flank and the seating surface is 0.3 mm to 1.0 mm, while sufficiently securing the tip rigidity in the direction directly below the cutting edge, It is possible to reliably exhibit the above-mentioned fracture resistance performance.

[Brief description of drawings]

1 to 6 are views for explaining an embodiment of a throw-away tip according to the present invention, wherein FIG. 1 is a top view, FIG. 2 is a bottom view, and FIG. 3 is FIG. III-III line arrow view of Fig. 4, Fig. 4 is an enlarged view of the IV portion of Fig. 3, Fig. 5 is a partial perspective view, and Fig. 6 is a side view showing a state where female threads are being processed by this tip. Is. FIG. 7 is a partial perspective view of a chip of another embodiment. FIG. 8 and FIG. 9 show a conventional chip.
Fig. 9 is a top view, Fig. 9 is a view taken along the line IX-IX in Fig. 8, and Figs. 10 to 12 show a state in which internal thread machining is performed by a conventional tip. Figure is a plan view, Figure 11 is a view taken along the line XI-XI in Figure 10, Figure 12 is an enlarged view of the XII section in Figure 11, and Figure 13 is a conventional model in which the lower surface side of the flank is missing. FIG. 14 is a partial perspective view of the tip of FIG. 14, and FIG. 14 is a partial perspective view of a conventional tip with a cutting edge missing. 4 ... cutting edge, 5 ... rake face (upper surface), 6 ... flank face,
7: Seating surface (bottom surface), 8: Holder, 11: Chips,
20 …… Chamfer.

Claims (1)

[Scope of utility model registration request] 1. A plate-shaped plate having at least one cutting edge for thread cutting formed on a ridge portion of an upper surface which is a rake surface, a side surface along the cutting edge being a flank surface, and a lower surface being a seating surface. In the throw-away tip for thread cutting, the ridge line portion intersecting the flank and the seating surface is chamfered so that the width in the direction along the flank and the seating surface is 0.3 mm to 1.0 mm. Throw-away tip for thread cutting.