JP2525893Y2 - Cutting tools - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary cutting tool used for a machine tool such as an end mill, a ball end mill, a drill, and a milling cutter, and more particularly, to ensure that coolant is reliably supplied to a cutting edge at the cutting edge of the tool. And a cutting tool configured as described above. In the present invention, the cutting tool is divided into a shank portion and a cutting blade portion, and both portions are collectively called a tool body.
The cutting edge portion is further divided into a middle cutting edge portion and a tip cutting edge portion, and the tip cutting edge portion is, for example, in the case of a torsion cutting tool, a first cutting edge counted from the tool tip. Say the area. The coolant refers to a fluid such as a cutting fluid or pressurized air that performs a cooling action and a chip discharging action in cutting.

[0002]

2. Description of the Related Art As a first prior art, for example,
The coolant flows from the rear end of the tool spindle described in Japanese Patent Application Laid-Open No. 2-21403 through the inside of the tool spindle, further flows through the tool holder attached to the tip of the tool spindle and the through hole of the tool, and the coolant is ejected from the tip of the tool. There is a so-called spindle through coolant. Also, a coolant rotating joint is provided in the tool holder, and coolant is sent from the outside into the tool holder without flowing the coolant through the tool spindle. There is a so-called tool-through coolant that is designed to be used. An example of an end mill disclosed in Japanese Utility Model Application Laid-Open No. 63-38917 discloses a cutting tool structure having a through hole used in these cases. That is, a hole is formed in the shaft center from the rear end of the tool, and a through hole is formed so as to branch into a fork just before the front end and open to the flank of the front end of the tool. Thus, the coolant is reliably supplied to the cutting portion.

As a second prior art, Japanese Utility Model Laid-Open No. 1-132 is disclosed.
No. 327 discloses a tap for a cast hole. This is a tap for a cast hole that penetrates the oil hole in the axial direction of the tap and has an oil groove communicating with the tap groove on the outer periphery of the shank. In the case of tapping of a blind hole, the tap is supplied from the oil hole and oil groove. Both coolants act as lubrication, cooling and chip evacuation. In the case of tapping of the through hole, the coolant supplied from the oil hole flows out of the work as it is, but the coolant is supplied from the oil groove provided on the outer periphery of the shank, so the effects of lubrication, cooling, and chip discharge are effective. It is done in.

As a third conventional technique, Japanese Utility Model Publication No. 4-274 is used.
No. 3 discloses an end mill. This is, as shown in FIG. 1 of the publication, at the outer rear end of the end mill body 20,
A coolant supply groove 25 extending from the rear end side of the end mill body to the chip discharge groove 22 along the longitudinal direction of the end mill body.
Is formed, and air, oil, or the like is jetted toward the groove 25. As a result, chips can be smoothly discharged, and further, since there is no hole at the tip of the tool, re-grinding can be performed.

[0005]

[Problems to be Solved by the Invention] Cutting is a process in which a tool that is harder and stronger than a work is pressed against the work while applying a rotational force to perform relative motion, and chips are generated by a shearing action to finish the work into a desired shape. is there. At this time, cutting heat is mainly generated by shearing work and frictional work between the chip and the tool. This frictional heat is transmitted to the tool, shortening the life of the cutting tool, and causing adverse effects such as forming a cutting edge and deteriorating the machining surface roughness. Therefore, it is necessary to quickly and surely cool the generated cutting heat with the coolant to eliminate these adverse effects.

For this purpose, high-pressure coolant is injected into a shearing portion of a workpiece where chips are generated and a friction portion between the chips and the rake face of the tool, and the generated cutting heat is not transmitted to the tool or the workpiece by the coolant. Chips that have been cooled and deprived and carry cutting heat must also be blown away with the coolant. In other words, high-pressure coolant having a sufficient pressure and flow rate must always be directly sprayed toward the cutting edge portion in the cutting portion.

The first prior art is to supply a coolant as close as possible to the cut portion. At that time, a through hole through which the coolant flows must be formed inside the end mill, but it is difficult to form this through hole in the case of a carbide tool or the like. In the case of a ball end mill or drill with a cutting edge at the center of the tool tip, it is necessary to form a through hole in the flank that avoids the cutting edge, so it is necessary to form a through hole that is bent or bifurcated. There is even more difficult. Further, in the case of a small-diameter end mill, the strength of the tool is reduced due to the formation of the through-hole, so that the shaft portion is liable to be cut or the cutting edge is chipped. Further, there is a problem that the inner diameter of the through hole itself cannot be increased, and a sufficient coolant flow rate cannot be secured.

[0008] The second prior art discloses a configuration of a tap as a tool for threading work, which is relatively low-speed cutting. The coolant supplied from the oil groove is low in pressure and small in volume, and the rotation of the tap is accompanied by rotation of the tap. It is preferable that the protrusions protrude from the oil groove and penetrate into the thread portion to be processed.

On the other hand, cutting tools such as end mills, milling cutters and drills cannot perform this conventional technique because they require relatively high-speed cutting. That is, in the case of a cutting tool such as an end mill that rotates at a high speed, a high-pressure coolant having a sufficient pressure and flow rate must be directly injected into the cutting portion. Therefore, there is a problem in applying the second conventional technique to cutting tools such as a ball end mill, a drill, and a milling cutter.

In the third prior art, since the concave coolant supply groove is formed only up to the chip discharge groove closest to the shank portion, when the coolant is ejected at a high pressure along the coolant supply groove, the shank portion is not formed. The coolant is repelled by the cutting edge portion close to the cutting edge, and there is a disadvantage that the coolant does not sufficiently reach the cutting edge portion of the tool tip.

This disadvantage is particularly remarkable in the case of processing that is usually performed frequently, such as relatively shallow grooving using only the end of the end mill or processing using the cutting edge at the end of a ball end mill or drill. There is a problem that sufficient cooling of the processing portion and rapid chip discharge are not performed.

Accordingly, an object of the present invention is to solve the above-mentioned problem, that is, a high-pressure coolant having a sufficient pressure and flow rate is always jetted directly to the rake face of the cutting edge of the cutting tool. It is to provide a cutting tool.

[0013]

The present invention solves the above-mentioned problems by adopting the following configuration. (1) In a cutting tool having a coolant supply groove,
At least one straight and concave coolant supply groove is formed on the outer periphery of the tool body from the rear end of the shank toward the cutting edge in parallel with the axis. A cutting tool with an opening facing the rake face of the blade. (2) In a cutting tool having a coolant supply groove,
At least one straight and concave coolant supply groove is engraved on the outer periphery of the ball end mill main body from the rear end of the shank portion toward the cutting edge portion in parallel with the axis.
A ball end mill that opens to the rake face of the cutting edge at the tool tip. (3) In a cutting tool having a coolant supply groove,
A coolant supply groove having a concave shape is formed in the outer periphery of the ball end mill main body in parallel with the axis from the rear end of the shank portion toward the cutting edge portion, and has a linear concave shape. A ball end mill provided with the number of cutting edges and opened toward the rake face of the cutting edge at the tool tip. (4) In a cutting tool having a coolant supply groove,
At least one straight and concave coolant supply groove is formed on the outer periphery of the end mill main body from the rear end of the shank toward the cutting edge in parallel with the axis. An end mill that penetrates the cutting edge and opens to the rake face of the cutting edge at the tool tip. (5) In a cutting tool having a coolant supply groove,
At least one straight and concave coolant supply groove is formed on the outer periphery of the drill body in parallel with the axis from the rear end of the shank portion toward the cutting edge portion. A drill that penetrates through the cutting edge and opens toward the rake face of the cutting edge at the tool tip.

[0014]

The cutting tool having the coolant supply groove of the present invention is mounted on a tool holder of a spindle device having a spindle through coolant device or a tool through coolant device, and when high-pressure coolant is discharged, the coolant is supplied to the cutting tool. It flows through the groove and squirts into the cutting part. At this time, the coolant supply groove is opened toward the rake face of the cutting edge at the tool tip, so that the coolant is always sprayed so as to directly hit the cutting edge at the tool tip, that is, the cutting portion. Therefore, the coolant is sprayed onto the rake face of the cutting edge at the tip of the tool while being kept at a high pressure without being hindered by the cutting edge in the middle. Coolant is spouted with sufficient pressure and flow rate while rotating at the same speed as the tool holder and cutting tool, so the cutting part is always cooled during machining regardless of the rotation speed of the tool, and chips are rapidly removed. It works to discharge to.

[0015]

FIG. 1 shows an example of an end mill according to the present invention.
2A is a front view, FIG. 2B is a sectional view taken along line AA of FIG.
Fig. 3 shows an example of the ball end mill of the present invention, (a) is a front view, (b) is a cross-sectional view taken along line BB of (a), Fig. 3 shows an example of the drill of the present invention, and (a) is a front view. , (B) is (a)
4 shows an example of the milling cutter according to the present invention. FIG. 4 (a) is a front view, FIG. 4 (b) is a DD sectional view of FIG. 4 (a), and FIG. 5 is an overall configuration of a coolant supply device. FIG. 6 and FIG. 6 are explanatory diagrams showing the operation of the coolant.

Referring first to FIG. 5, a tool spindle 1 is rotatably supported by a bearing 3 on a spindle housing 2 and is rotated by a driving device (not shown). 4 is a bearing retainer. The tool holder 5 is mounted in a tapered end of the tool spindle 1 by pulling up a pull stud 6 screwed to a rear end portion thereof with a draw bar 7. Reference numeral 8 denotes a key for positioning the tool holder 5 in the rotation direction. A pipe 9 is inserted into the inside of the draw bar 7, and the tip of the pipe 9 is in contact with the pull stud 6, and rotates integrally with the tool spindle 1. A fluid rotary joint 10 is provided at the rear end of the pipe 9, and the coolant discharged from the coolant supply source 11 is sent into the pipe 9.

On the other hand, an end mill 12 is detachably mounted on the tip of the tool holder 5. On the outer periphery of the tool body of the end mill 12, a coolant supply groove 13 having a concave shape described later is formed up to just before the cutting edge at the tip. Pull stud 6,
A through hole communicating with the pipe 9 is formed in the tool holder 5. The coolant discharged from the coolant supply source 11 passes through the pipe 9, the pull stud 6, and the tool holder 5, and is provided with a coolant supply groove of the end mill 12. The end mill 12 is configured to flow through the end mill 12 and to be finally jetted toward the cutting edge portion.

Next, the end mill 12 of the present invention will be described in detail with reference to FIG. Shown is a four-flute end mill with twisted cutting edges 14a, 14b, 14c, 14d.
And an escape groove 15. On the outer periphery of the shank 16, a concave coolant supply groove 13 extends from the rear end face 17 of the end mill 12 in parallel with the axis, and passes through a cutting edge part in the middle, and the cutting edge 14 a, 14 c
Two are engraved toward the foremost part of. Here, in FIG. 1, two coolant grooves are drawn in order to reduce the complexity of the drawing. However, in the case of a four-flute end mill, four coolant grooves are provided, and each of the cutting edges at the tool tip is raked. It is desirable to have the coolant injected directly on the surface. The coolant supply groove 13 is a part engraved on the shank
13a, a portion 13b penetrating the cutting edge 14c, and a portion 13c penetrating the cutting edge 14b, which are linearly connected and regarded as one groove. This coolant supply groove 13
May be not only a square shape as shown in the figure, but also other shapes such as a semicircular shape and a semielliptical shape. And 2
The diameter d of the depth of the coolant supply groove 13 is smaller than the outer diameter D of the cutting blade 14, that is, the coolant supply groove 13 is cut to a depth smaller than the outer diameter of the cutting blade. This is because the coolant supply groove 13 opens toward the cutting edge at the forefront. That is, the extension line of the coolant supply groove 13 is configured to always hit the cutting edge portion 14 at the tool tip.

Therefore, for an end mill in which the outer diameter of the shank is larger than the outer diameter of the cutting edge, it is necessary to form a deep coolant supply groove. Sharp portions such as the intersection between the coolant supply groove 13b and the cutting blade 14c and the intersection between 13c and 14b are chamfered to prevent chipping of the cutting blade.

As shown in FIG. 6, the shank 16 of the end mill 12 is mounted in the tool mounting hole 18 of the tool holder 5, and the coolant flows through the hole 19 into the tool mounting hole 18. Then, the coolant becomes two coolant supply grooves 1
3 and 13 are circulated and are ejected toward the tip of the end mill 12. During machining by the end mill 12, the tool spindle 1, the tool holder 5, and the end mill 12 rotate together, and the internal coolant also rotates at a constant speed. Even when the spindle is rotated at a high speed, the coolant supplied from the coolant supply groove 13 is supplied at a high pressure (for example, 70 kg / cm ² ) such that the coolant ejected from the coolant supply groove 13 is reliably injected at a high pressure into the cutting edge portion of the tool tip. The high-pressure jet coolant jetted from the coolant supply groove 13 directly hits the cutting edge of the tool tip. The cross-sectional area of the coolant supply groove 13 can be made larger than the hole formed in the end mill, and the flow rate can be reduced accordingly. Therefore, in any case, the coolant is always supplied at a sufficient pressure and flow rate to the cutting edge portion of the tool tip, that is, the cutting portion, and quickly acts to remove heat and discharge chips.

In the case of deep groove processing or side processing in which the entire cutting edge portion of the end mill 12 in the direction from the shank to the tip direction is used, the gap between the coolant supply grooves 13a and 13b and the opening between 13b and 13c are set. The coolant leaks out, and the coolant is supplied not only to the tool tip but also to the entire cutting edge, so that the cutting heat can be removed and the chips can be discharged for any machining.

There is a conventional method in which a coolant discharge nozzle is provided outside an end mill that rotates at a high speed, and the coolant is sprayed from the nozzle toward the end mill. However, around the end mill that rotates at a high speed, the coolant rotates at a substantially constant speed. There was an air layer, and it was difficult to break the air layer and apply coolant directly to the rake face of the cutting edge of the end mill. That is, even if the coolant is injected from the outer portion of the high-speed rotating end mill, most of the coolant only hits the flank of the cutting edge. In the conventional method, almost all of the coolant is blown off in the air layer, and heat removal from the rake face of the cutting edge portion of the end mill and discharge of chips are not effective. The present invention has been made by paying attention to this point, and has a different technical idea from the conventional method and apparatus.

According to the present invention, even when the end mill is rotated at a high speed in a state where the coolant is circulated in the concave coolant supply groove formed in the end mill, the rotation of the end mill and the inside of the air layer surrounding the outer periphery of the end mill are realized. At the same time, the coolant already exists, and the high-pressure coolant can be jetted directly to the rake face of the cutting edge of the end mill without having to break the air layer.

As the coolant, not only a liquid such as a cutting fluid, but also pressurized air is used, and this air is circulated through the coolant supply groove and jetted to the cutting blade to cool the cutting blade and discharge chips. It may be performed.

The end mill according to the present invention, having such a structure, has no difficulty in forming a through hole in the end mill, which is a problem of the prior art. Is insufficient, and a sufficient amount of coolant is not secured because the through hole is small in diameter. In addition, the coolant flowing through the coolant supply groove is always sprayed so as to directly hit the cutting edge portion of the tool tip, and is not repelled at the cutting edge portion near the shank portion. Furthermore, there is no need to manually or automatically adjust the nozzle angle as in the case of coolant supply by a coolant discharge nozzle provided outside, and further, coolant is not directly projected to the cutting part depending on the work shape or processing part. Has solved the problem that the coolant is repelled to the air layer that circulates at substantially constant speed around the outer periphery of the end mill.

In this embodiment, the case where two coolant supply grooves are formed is described with reference to FIG. 1. However, as described above, the greatest effect is obtained if the coolant supply grooves are provided by the number of cutting edges.
Needless to say, only one coolant supply groove has a certain effect. Further, the present invention can be applied to an end mill having a number of blades, a small-diameter end mill, and a throw-away type end mill. However, in the case where the coolant supply groove is engraved in the same number as the number of cutting edges, the coolant supply groove is formed in the cross section of FIG.
It is necessary to shift the height positions of the deficient portions of the cutting blades due to the supply grooves with an unequal angle pitch. Further, the number of coolant supply grooves may be smaller than the number of cutting edges. Further, it goes without saying that a tool through coolant system in which coolant is introduced into the tool holder may be used instead of the spindle through coolant system.

Next, an embodiment of the ball end mill shown in FIG. 2 will be described. The ball end mill of FIG. 2 is a four-blade ball end mill in which four coolant supply grooves 13 are provided.

The coolant supply groove 13 is formed in the shank portion 16 from the rear end face 17 of the shank in a straight line parallel to the axis of the shank 16. The coolant supply groove 13 is open toward the rake face of each of the cutting blades 14a, 14b, 14c, 14d.

Also in this ball end mill, FIG.
As described in the end mill shown in FIG. 1, the high-pressure jet coolant passes through the coolant supply groove 13 and the cutting edge 1 at the tool tip.
Directly to the rake face of 4a, 14b, 14c, 14d
As a result of the high-pressure jet coolant, not only heat generated by cutting of the cutting edge portion is taken away, but also chips that are to adhere to the cutting edge portion are directly hit and scattered. Therefore, the operation and effect are the same as those described for the end mill. Here, the description is omitted because it is duplicated.

Next, the case of the drill shown in FIG. 3 will be described. The coolant supply groove 13 extends in parallel from the rear end face 17 of the shank to the rake face of the cutting edge 14 at the tip of the drill, penetrating the cutting edge in the middle and in a straight line parallel to the axis. It is engraved. It should be noted that the dashed line 20 in the figure indicates the locus when the drill rotates.

Next, the case of the milling cutter shown in FIG. 4 will be described. Here, a groove milling machine is shown as a representative example. Five coolant supply grooves 13 are formed in the shank 16 from the rear end face 17 in a straight line parallel to the axis and toward the rake face of the cutting edge portion 14 at the tool tip. In both the case of the drill and the case of the milling cutter, the operation and effect described in the end mill of FIG. 1 are provided, but the description is omitted here because they are duplicated.

[0032]

As described above, according to the cutting tool having the coolant supply groove of the present invention, the high pressure coolant is scooped into the concave coolant supply groove formed on the outer periphery of the tool body at the cutting edge of the tool tip. Since it is ejected so as to directly hit the surface with high pressure, a high-pressure coolant with a sufficient pressure and flow rate is always supplied to the cutting portion during processing without being hindered by a cutting edge portion in the middle. Therefore, the cutting heat is removed and the chips are discharged quickly and reliably in the cutting section, so that the machining efficiency is improved. Also, since there is no biting of the chips, high-precision cutting can be performed. Further, since the heat removing effect is large, the life of the tool to be used is prolonged, which is economical. Further, it is easy to form a concave groove in the cutting tool, and there is an advantage that it can be manufactured at a lower cost than an end mill having a through hole.

[Brief description of the drawings]

FIG. 1 shows an example of an end mill according to the present invention, and (a).
2 is a front view, and FIG. 2B is a sectional view taken along line AA of FIG.

FIG. 2 shows an example of a ball end mill according to the present invention,
(A) is a front view, (b) is BB sectional drawing of (a).

3A and 3B show an example of a drill according to the present invention, wherein FIG. 3A is a front view, and FIG. 3B is a cross-sectional view taken along line CC of FIG.

FIG. 4 shows an example of a milling cutter according to the present invention;
(A) is a front view, (b) is DD sectional drawing of (a).

FIG. 5 is a configuration diagram of a coolant supply device.

FIG. 6 is an explanatory diagram of a coolant supply operation.

[Explanation of symbols]

 Reference Signs List 1 Tool spindle 5 Tool holder 9 Pipe 10 Fluid rotary joint 11 Coolant supply source 12 End mill 13 Coolant supply groove 14 Cutting edge 16 Shank.

Claims (5)

(57) [Scope of request for utility model registration] 1. A cutting tool having a coolant supply groove, wherein at least one straight and concave coolant supply groove is formed on the outer periphery of the tool body from the rear end of the shank portion toward the cutting edge portion in parallel with the axis. A cutting tool, wherein the cutting tool is formed by engraving, and the coolant supply groove is opened toward a rake face of a cutting edge portion at a tool tip. 2. A cutting tool having a coolant supply groove, wherein at least one straight and concave coolant supply groove is formed on the outer periphery of the ball end mill main body from the rear end of the shank toward the cutting edge in parallel with the axis. A ball end mill which is formed by engraving, and wherein the coolant supply groove is configured to open toward a rake face of a cutting edge portion of a tool tip. 3. A cutting tool having a coolant supply groove, wherein a concave coolant supply groove is formed in the outer periphery of the ball end mill main body, which is parallel to the axis and straight and concave from the rear end of the shank portion toward the cutting blade portion. , the coolant supply groove, the ball end mill, characterized in that provided with the number of cutting of the cutting portion of the tool tip, which is configured to open the mouth toward the rake face of the cutting edge of the tool tip. 4. A cutting tool having a coolant supply groove, wherein at least one straight and concave coolant supply groove is formed on the outer periphery of the end mill body from the rear end of the shank toward the cutting edge in parallel with the axis. Installed, the coolant supply groove,
An end mill having a configuration in which a cutting edge of a middle cutting edge portion is penetrated and opened toward a rake face of a cutting edge portion of a tool tip. 5. A cutting tool having a coolant supply groove, wherein at least one straight and concave coolant supply groove is formed on the outer periphery of the drill body from the rear end of the shank toward the cutting edge in parallel with the axis. The drill is characterized in that the coolant supply groove penetrates the cutting edge of the cutting edge partway through and opens to the rake face of the cutting edge part at the tool tip.