JPH042739Y2 - - 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 respect to each other across the axis and spaced apart from each other in the axial direction, and two cutting blade tips 2b... are placed in the circumferential intermediate portions of these cutting blade tips 2a... in the axial direction. The opposing ends of the cutting blade tips 2a, 2a adjacent to each other in the axial direction and both ends of the cutting blade tip 2b overlap in their rotational trajectories, and the cutting blade tips 2a, 2b... as a whole, the work material can be cut flatly. In addition, the reference numeral 3 in the figure is a clamp screw for fixing the cutting blade tips 2a, 2b to the tool body.

With such an end mill, it is possible to cut a width that is much longer than the cutting edge length of a single cutting tip with a single feed, so it is possible to improve the processing efficiency of the cutting process. Further, there are advantages such as being able to cut 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, which tends to cause chatter in the cutter. 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 chipping of cutting edges due to chatter of a cutter, and can therefore perform heavy cutting.

[Means for solving the problem] This invention achieves the object, and includes a hydraulic chamber extending in the direction along the axis of the tool body, and a hydraulic chamber that communicates with the hydraulic chamber and has one end connected to the hydraulic chamber. A hole is formed in the outer wall surface of the tool body, the hydraulic chamber is filled with liquid, and a screw member for increasing the pressure of the liquid is screwed into the open end of the hole.

[Operation] In the cutting tool having the above configuration, the inner wall of the hydraulic chamber is pressed by the internal liquid to apply tensile force to the tool body in the axial direction and the circumferential direction. Internal stress is generated inside the main body to resist the tensile force. For this reason, the tool body itself has high rigidity and excellent damping ability, and not only does it not easily deform elastically even when subjected to large impact forces, but it also resists vibration even when chatter occurs. 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. FIG. 1 and FIG. 2 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, . . Inside this tool body 4, one end is located at a tip end surface (one end surface) 4 of the tool body 4.
A hole (hydraulic chamber) 5 that opens in the direction a and whose other end reaches the rear end of the tool body 4 is formed so that its axis coincides with the axis of the tool body 4. A screw hole portion (hole) 6 is formed at the open end of this hole 5 . A screw member 7 is provided in the screw hole 6 so as to be movable in the axial direction.

The screw member 7 has a cylindrical shape, and has a thread formed on its outer peripheral surface at one end and an O-ring 8 attached to the other end. This screw member 7
is screwed onto the threaded portion 6 with its O-ring 8 in liquid-tight contact with the inner wall surface of the hole 5. The inside of the hole 5 is filled with hydraulic oil (liquid) 9. The hydraulic oil 9 is maintained at a high pressure by screwing the screw member 7 toward the inside of the hole 5, and this pressure presses the inner wall of the hole 5.

In such an end mill, by pressing the inner wall of the hole 5 with the internal hydraulic oil 9, a tensile force is applied to the inside of the tool body 4 in the axial direction and the circumferential direction. An internal stress is generated inside the tool body 9 that resists the tensile force. For this reason, the tool body 4 itself has high rigidity and has excellent damping ability.
Not only does it not easily undergo elastic deformation even when subjected to a large impact force, but it can also absorb chatter even if it occurs. Therefore, the cutter does not shake even during heavy cutting, and the cutting blade tips 2a, 2b
It is possible to effectively prevent damage to the cutting edge of...

Further, in the above end mill, the screw member 7
Since the magnitude of the tensile force can be adjusted by appropriately changing the amount of screwing in, the optimal magnitude of the tensile force can be set depending on the cutting conditions. Further, since one end of the hole 5 is opened at the tip end surface 4a of the tool body 4, the magnitude of the tensile force can be adjusted while performing the cutting process, and the adjustment work can be facilitated.

Further, FIGS. 3 to 5 are diagrams showing still other embodiments of the present invention. The end mill shown in these figures has a tool body 10 formed with a hole (hydraulic chamber) 11 that opens on the rear end surface, and a screw hole (hole) 12 formed at the open end of this hole 11. The same screw member 7 as in the above embodiment is screwed into the portion 12, and the inside of the hole 11 is filled with hydraulic oil 9, and the same effect as in the above embodiment is achieved.

In the above embodiment, the screw member 7 is screwed into the open end of the hole 11, but the structure is not limited to this. For example, the screw member 7 is screwed into the open end of the hole 11. The internal hydraulic oil 9 is tightly screwed.
A hole with a smaller diameter than the inner diameter of the hole 11 is formed in the tool body 10, one end communicating with the hole 11 and the other end opening on the outer peripheral surface of the tool body 10, and a screw is inserted into the open end of the hole. The member may be provided movably in the axial direction of the hole. With this kind of end mill,
Since the inner diameter of the hole is smaller than the inner diameter of the hole,
The screw member can be screwed in with a small force.

In addition, although the above embodiments are all examples in which the present invention is applied to an end mill, the same effects as described above can be obtained even if the present invention is applied to various other cutting tools such as a milling cutter, a boring bar, or a drill.

[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 that communicates with a hydraulic chamber extending in the direction along the axis of the tool body, and one end of which opens on the outer wall surface of the tool body. By screwing together a screw member that increases the pressure of the liquid, a tensile force is applied to the tool body in the axial direction and circumferential direction, so internal stress that resists the tensile force is created inside the tool body. It has occurred. For this reason, the tool body itself has high rigidity and excellent damping ability, and not only does it not easily undergo elastic deformation even when subjected to large impact forces, but it also resists vibration even when chatter occurs. can be absorbed. Therefore,
The cutting tool does not shake even during heavy cutting,
The effect of effectively preventing damage to the cutting edge of the cutting edge tip is obtained.

[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 to 5 are views showing other embodiments of the present invention, FIG. 3 is a fragmented sectional view showing an end mill, and FIG. FIG. 3 is a view in the direction of arrows in FIG. 3, FIG. 5 is a view in the direction of FIG. 3, FIGS. 6 to 8 are views showing examples of conventional cutting tools, and FIG. 6 shows an end mill. The side view, Figure 7, is the direction arrow view of Figure 6, Figure 8.
The figure is a sectional view taken along the line -- in FIG. 6. 1... Tool body, 2a... Cutting tip, 2b...
... Cutting blade tip, 4 ... Tool body, 4a ... Tip surface (one end surface), 5 ... Hole (hydraulic chamber), 7 ... Thread member,
9...Hydraulic oil (liquid), 10...Tool body, 11
...Hole (hydraulic chamber).

Claims (1)

[Scope of utility model registration request] A cutting tool in which a cutting tip is attached to the outer periphery of a tip of a tool body that is rotated about an axis, and a hydraulic chamber that extends in a direction along the axis within the tool body, and that communicates with the hydraulic chamber. ,
A hole is formed at one end opening in the outer wall surface of the tool body, and a liquid is filled in the hydraulic chamber, and a screw member for increasing the pressure of the liquid is screwed into the open end of the hole. Characteristic cutting tools.