JPS6190814A - Annular boring cutter - Google Patents

Abstract

PURPOSE:To reduce manpower required for formation of edge and regrinding by splitting the central angle at the lower end of cutter body into three then arranging three cutters at respective splitted section while gradually lowering the height from the initial stage cutter toward the rear stage cutter. CONSTITUTION:Three types of cutter or an inner cutter 13, an intermediate cutter 15 and an outer cutter 17 are formed sequentially in every 1/3 section of the entire circumference of cutter section 11. The lower endface of a set of cutter section 11 is on a convex surface making contact angle of 2-5 deg. against the horizontal face while rising from the inner cutter 13 toward the outer cutter 17. In other word, the side flank of the cutters 13, 15, 17 is an outercircum ferential locus of grinding wheel or a convex face. Consequently, plural cutter lower faces are grinded through single pass resulting in reduction of manpower.

Description

Detailed Description of the Invention: a. Field of Industrial Application The present invention relates to an annular perforating cutter, and more specifically, the cutting edge setting part center angle at the tip of the cylindrical cutter main body is equally divided into two parts. A plurality of cutting blades are each provided.The height position of the plurality of cutting blades is from the cutting blade that performs the first cutting to the cutting blade that performs the subsequent cutting, and the height position of the cutting blade in the plurality of stages is from the cutting blade that performs the first cutting to the cutting blade that performs the subsequent cutting, and the height position of the cutting blade in the plurality of stages is such that the height position of the cutting blade in the multiple stages is from the cutting blade that performs the first stage cutting to the cutting blade that performs the subsequent cutting, and This invention relates to an annular punching cutter that is formed to have a shorter height in order to match one of the continuous convex grinding curved surfaces that are in contact with the outer circumferential locus.

b. Conventional technology Originally, an annular perforating cutter was provided with a number of cutting blades approximately equal to the wall thickness of the cylinder at one end of the cylindrical cutter body, and was driven to rotate around an axis, leaving a core part and cutting almost outside the cylinder. A tool for drilling holes with a round diameter.

Therefore, it is characterized by having a large number of cutting edges in an annular shape, and effective grinding must be performed quickly and easily both when creating this large number of cutting edges and when re-grinding.

C8 Problems to be Solved by the Invention Conventional annular perforating knives had a disadvantage in that many cutting edges had unique shapes, dimensions and angles, and that creating and re-grinding them required a large number of man-hours.

Means for Solving the d1 Problem In the annular perforated cutter of the present invention, the outer periphery of the cutter body is divided into a plurality of identical central angles, and each divided group has a cutting blade that performs the initial cutting and a cutting blade that performs the subsequent cutting. The height of the cutting blade was changed to be short so that the lower surface of the cutting blade coincided with a part of one medium concave curved surface.

80 Function The annular perforating cutter of the present invention is constructed as described above. For example, the center angle of the lower end of the blade body is divided into three equal parts of 120 degrees each, and three cutting blades are arranged in each divided part, with the height of the cutting blade gradually decreasing from the first cutting edge to the later cutting edge. Suppose we set

Since the lower surfaces of these three cutting blades are located on one medium-convex grinding curved surface, it is possible to grind three cutting blades at once by adjusting the grinding device twice, and it rotates 120 degrees. This allows the bottom surface of all cutting edges to be ground.

In addition, the flank surface in the radial direction of the cutter body is a concave curved surface due to the outer circumferential trajectory of the grinding wheel, and the flank flank surface of each cutting edge is a convex curved surface, so once the grinding device is adjusted, the
It is possible to grind three equal cutting edges with a rotation of 20 degrees.

f. Example As shown in FIG. 1, the annular perforating cutter 1 consists of a cylindrical cutter body 3 and a shank portion 5. A plurality of threads are formed at approximately equal pitches, twisting upward from the lower tip.

The shank portion 5 is a portion that is attached to a drilling machine and driven to rotate, and is provided with through holes 9 at the top and bottom for passing cutting oil.

The cutting edge 11 of the embodiment shown in FIG.
Three types of blades, an inner cutter 13, a middle cutter 15, and an outer cutter 17, each having a angle of /3 (120 degrees), are formed in order. Gullet portions 13G, 15G, and 17G are provided on the front side of each cutting edge in the rotational direction to communicate the above-mentioned twist member 7 with the inside of the cylinder.

Each of the above-mentioned gullets 13G, 15G, and 17G is provided with an upward slope on the side of the helical groove 7, so that chips 19 from each cutting edge are guided to the helical groove 7, and further in the helical groove 7.
It is moved above the annular punching cutter 1 shown in the figure and carried above the workpiece W.

A back lead 21 is provided on the inner wall of the outer cutter 17 and serves as an oil groove to help the cutting oil flow into the cutting part.

Fig. 3 is a developed view of the inner cutter 13, middle cutter 15, and outer cutter 17 shown in Fig. 1, and the lower end surface of the three cutting blades in one set has a tangent angle α to the horizontal plane.
It is on a medium convex curved surface that becomes higher from the inner cutter 13 to the outer cutter 17 at an angle of 2 degrees to 5 degrees.

In FIG. 4, viewed from the left side of FIG. 3, the lower end surfaces of the same set of three cutting blades are in a parallel state forming a concave curved surface.

Furthermore, as is clear from FIG. 4, the lower outer sides of the inner cutter 13 and the middle cutter 15 are shaved off by a concave curved surface.
The middle blade 15 cuts approximately 2/3 of the cutting edge of the outer blade 17, and the inner blade 13
Approximately 1/3 of the cutting edge of the outer cutter 17 is held.

FIG. 5 shows, for example, the inner cutter 13 in FIG. 4 viewed from below, and as mentioned above, both the lower surface of the inner cutter 13 and the shaved part indicated by diagonal lines have a concave curved surface. It is.

Therefore, as shown in FIG. 4, each cutting edge is 13°15°.
Each of the blades 17 is a single tip blade that is inclined outward in the radius of the blade body 3.

Further, the side flank surfaces of each of the cutting edges 13, 15, and 17 have a convex curved surface that corresponds to the outer periphery of the grinding wheel.

Fig. 6 shows the lower surface of the conventional cutting blade (A>) and the lower surface of the cutting blade of the present invention (B). The grinding process is carried out by rotating the whetstone in the distance parallel to the edge of the cutting edge.

Therefore, unlike the conventional method (A), the grinding curved surface of the cutting edge is smooth and chipping is less likely to occur during cutting 1].

g1 Effects of the Invention The annular perforating cutter that embodies the technical idea of the present invention has a cutting edge setting part whose center angle is evenly divided. Since the plurality of cutting blades in each divided portion are aligned with one medium convex grinding curved surface, and the height of the blade in the latter stage is shorter than that in the preceding stage, the lower surfaces of the plurality of cutting blades can be ground in one pass. Therefore, by repeating the above-mentioned number of equal divisions, grinding of the lower surfaces of all J cutting blades can be completed in one adjustment.

Furthermore, since all the side clearance angles are composed of a medium concave curved surface and a medium convex curved surface, by rotating the cutting edge setting part center angle evenly by the division angle in - times adjustment of the grinding machine, the same position can be achieved. This resulted in the effect that the cutting edge of the order could be easily ground.

It is also clear that the settings can be easily changed without departing from the technical idea of the present invention.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the annular punching blade of the present invention, Figure 2 is an enlarged partial view of the bottom of the same as above, Figure 3 is a developed view of each cutting blade at the tip of the blade body, and Figure 4 is during drilling work of the present invention. FIG. 5 is a bottom view of FIG. 4, and FIG. 6 is an explanatory view showing the grindstone opening of the cutting blade.

Claims (4)

[Claims] (1) The center angle of the cutting blade setting part at the tip of the cylindrical blade body is equally divided, and each divided part is provided with multiple stages of cutting blades,
The height positions of the plurality of stages, from the cutting blade that performs the first stage cutting to the cutting blade that performs the second stage cutting, coincide with one of the continuous convex grinding curved surfaces that are in contact with the outer peripheral locus of the grinding wheel in the axial direction of the blade body. An annular perforating cutter characterized by being formed in sequentially short dimensions. (2) The annular perforating blade according to claim 1, wherein the grinding curved surface is spherical. (3) The annular perforating cutter according to claim 1, wherein the radial flank of each of the cutting edges is a concave curved surface formed by the outer peripheral locus of a grinding wheel. (4) The annular perforating cutter according to claim 1, wherein the side flank face of each of the cutting edges is a medium convex curved surface formed by the outer peripheral locus of a grinding wheel.