JPH042737Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to the improvement of a cutting tool such as an end mill that performs cutting by feeding a cutter laterally.

[Prior art] Conventionally, as an end mill,
There is one shown in the figure. The end mill shown in these figures has three cutting tips 2 on the outer periphery of the tip of a tool body 1 that rotates around its axis.
a... are positioned point-symmetrically with each other across the axis,
and are arranged spaced apart from each other in the axial direction, and two cutting blade tips 2a... are respectively arranged in the circumferential middle part of these cutting blade tips 2a... spaced apart from each other in the axial direction, Opposing ends of cutting blade tips 2a, 2a adjacent in the direction;
Both ends of the cutting blade tip 2b overlap in their rotation loci, and the cutting blade tips 2a, 2b
...The overall structure allows for flat cutting of the work material. In addition, the code 3 in the figure
are clamp screws for fixing the cutting blade tips 2a, 2b to the tool body.

With such an end mill, it is possible to cut a width much longer than the cutting edge length of a single cutting tip with a single feed.
This method has advantages such as being able to improve the processing efficiency of the cutting process and being able to perform the cutting process at a considerably deep part of the upper surface of the workpiece.

[Problems to be solved by the invention] Generally, when cutting is performed using an end mill, each cutting edge tip repeats cutting and non-cutting every time the cutter rotates once, resulting in an interrupted cutting process. Impact force is applied repeatedly to the chip. For this reason, the impact force is transmitted to the tool body, causing the cutter to vibrate, making the cutting edge of the cutting tip more likely to break. However, in the above-mentioned end mill, since the plurality of cutting tips are spaced apart from each other in the axial direction of the tool body, the length of the part of the tool body where the cutting tips are attached becomes long. ing. For this reason, a large impact force is applied to the tool body during cutting, and the cutter tends to chatter. Therefore, in order to prevent damage to the cutting edge due to cutter chatter, there has been a problem in that cutting conditions must be significantly restricted, such as by limiting the material of the workpiece or reducing the depth of cut.

This idea was made in view of the above circumstances,
It is an object of the present invention to provide a cutting tool that can effectively prevent the cutting edge of a cutting tip from being damaged due to chatter of the cutter, and can therefore perform heavy cutting.

[Means for Solving the Problems] This invention achieves the object, and has at least one end opening in one end surface of the tool body, and a direction along the axis of the tool body. A hole extending to the tool body is formed, and a pin made of a metal having a higher elastic modulus than the tool body is integrally fitted into the hole.

[Function] In the cutting tool with the above configuration, a pin made of a metal with a higher elastic modulus than the tool body is fitted into the hole in the tool body, so the cutting tool itself resists bending deformation. It has high rigidity and excellent damping ability. Therefore, even if the tool body receives a large impact force, it will not easily undergo elastic deformation, and even if chatter occurs, it can be absorbed.

[Example] An example of this invention will be described below with reference to Figures 1 and 2.
This will be explained with reference to the figures. 1 to 5 are diagrams showing an end mill according to an embodiment.

In FIG. 1, reference numeral 4 indicates a tool body. The tool body 4 has a cylindrical shape, and a plurality of cutting tips 2a, 2b, . There is. This tool body 4 is formed with a hole (hole portion) 5 whose one end opens at the center of the distal end surface (one end surface) 4a of the tool body 4 and whose other end extends to the rear end of the tool body 4. A pin 6 is fitted into this hole 5. The pin 6 is made of cemented carbide and has a diameter slightly larger than the inner diameter of the hole 5. In addition,
The pin 6 is fitted into the hole 5 by shrink fitting.

Since such an end mill has a pin 6 made of cemented carbide fitted into the hole 5 of the tool body 4, it has high rigidity against bending deformation and has excellent damping ability. Moreover, since the diameter of the pin 6 is slightly larger than the inner diameter of the hole 5, the inner circumferential surface of the hole 5 is pressed in the radial direction by the outer circumferential surface of the pin 6. A compressive force in the radial direction and a tensile force in the circumferential direction are applied. Therefore, internal stress that resists the compressive force and the tensile force is generated inside the tool body 4, and the tool body 4 has high rigidity and excellent damping ability.

Therefore, in the above-mentioned end mill, not only does the tool body 4 not easily undergo elastic deformation even when subjected to a large impact force, but even if chatter occurs, it can be absorbed, making it suitable for heavy cutting. The end mill does not shake even when the cutting edge is cut with 2 tips.
Breakage of the cutting edges a, 2b, . . . can be effectively prevented.

Further, FIGS. 3 and 4 are diagrams showing still other embodiments of the present invention. The end mill shown in these figures has four holes (holes) 8 in the tool body 7, one end of which opens at the center of the distal end surface of the tool body 7 and extends in the axial direction, at equal intervals in the circumferential direction. form,
A pin 9 made of cemented carbide having a diameter slightly larger than the inner diameter of the hole 8 is fitted into each hole 8, and the same effect as in the above embodiment is achieved. It is.

In the above embodiment, the pin 9 is made of cemented carbide, but if it is made of an ultra-hard sintered alloy such as CBN or a tungsten-based sintered metal (so-called heavy alloy), the end mill can be used. Its own rigidity and damping capacity can be further increased. Further, although the diameter of the pin 9 is larger than the inner diameter of the hole 8, a pin having a smaller diameter than the inner diameter may be fitted inside the hole 8 and the two may be joined by brazing. Furthermore, holes may be formed in the tool body 7 that open on both end faces thereof, and the pins 9 may be fitted into the holes. Furthermore, the present invention is not limited to end mills as in the above embodiments, but can also be applied to milling cutters, boring bars, drills, etc. to obtain the same effects as in the above embodiments.

[Effects of the invention] As explained above, the cutting tool of this invention has the following effects:
A hole is formed in the tool body, and at least one end thereof is open to one end surface of the tool body and extends in the direction along the axis of the tool body. Since the cutting tool itself has a structure in which the pins are integrally fitted, the cutting tool itself has high rigidity against bending deformation, and has excellent damping ability. Therefore, even if the tool body receives a large impact force, it will not easily become elastically deformed, and even if chatter occurs, it can be absorbed, so the cutting tool will not vibrate even during heavy cutting. , it is possible to effectively prevent the cutting edge of the cutting edge from being damaged.

[Brief explanation of the drawing]

1 and 2 are views showing one embodiment of the present invention, in which FIG. 1 is a side view showing an end mill;
FIG. 2 is a view taken in the direction of the arrow in FIG. 1, FIGS. 3 and 4 are views showing still other embodiments of the present invention, FIG. 3 is a side view showing the end mill, and FIG. FIG. 3 is a view in the direction of arrows, FIGS. 5 to 7 are views showing an example of a conventional cutting tool, FIG. 5 is a side view showing an end mill, and FIG. 6 is a view in the direction of FIG. 5. The arrow view and FIG. 7 are cross-sectional views taken along the - line in FIG. 1... Tool body, 2a... Cutting tip, 2b...
... Cutting blade tip, 4 ... Tool body, 4a ... Tip surface (one end surface), 5 ... Hole (hole), 6 ... Pin, 7 ...
…Tool body, 8…hole (hole), 9…pin.

Claims (1)

[Scope of utility model registration request] In a cutting tool in which a cutting tip is attached to the outer periphery of the tip of a tool body that is rotated about an axis, at least one end is opened in one end surface of the tool body and extends along the axis. 1. A cutting tool comprising: a hole extending in the direction; and a pin made of a metal having a higher elastic modulus than the tool body is integrally fitted into the hole.