JP2010142889A - Tool holder, cutting fluid supply plate for holding tool and cutting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that cutting fluid supplied to cool a tool and prolong tool life is spread by centrifugal force and the cutting fluid is not securely supplied to a processing part when a main shaft rotates at high speed though the high speed rotation of the main shaft of a machine is achieved for improving productivity or the like in cutting by the machine tool such as a machining center recently. <P>SOLUTION: The tool holder holds the cutting tool T at a rotating axis and supplies the cutting fluid c to a cutting part which the cutting tool cuts. The tool holder includes: a cutting fluid path for passing the cutting fluid; and a cutting fluid supply hole positioned at the end of the cutting fluid path and jetting the cutting fluid passing the cutting fluid path. The cutting fluid supply hole is configured of two or more cutting fluid holes which are different in length from the rotating axis. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a tool holder for holding tools such as end mills and drills used for machining. More specifically, it is a tool holder with a cutting fluid internal supply function that supplies cutting fluid during cutting processing, and even when machining at high speed rotation, the cutting fluid is reliably supplied to the cutting part and the tool is effective. The present invention relates to a tool holder that can be cooled.

In recent years, in the machining with a machine tool such as a machining center, the spindle speed of the machine has been increased for the purpose of improving productivity.
During the cutting process, a cutting fluid (also referred to as coolant) is supplied to the cutting unit for the purpose of cooling the tool and extending the tool life.
Conventionally, as a method of supplying the cutting fluid, a nozzle is provided outside the vicinity of the tool, and an external oil supply method in which the cutting fluid is ejected from the nozzle toward the machining site. A cutting fluid supply hole is provided in the tool itself, and cutting is performed from this hole. There is an internal oil supply system that supplies liquid. In the internal lubrication system, a cutting fluid supply hole is provided in the tool holder and the cutting fluid is supplied from this hole. A cutting fluid supply groove parallel to the shaft is provided on the outer periphery of the tool shank and the cutting fluid is supplied from the cutting fluid supply groove. A gap supplying method (also referred to as a gap through method or a collet through method) is disclosed (for example, see Patent Documents 1 to 3).

Japanese Utility Model Publication No. 7-12730 Japanese Utility Model Publication No.7-17452 JP-A-6-31521

When the machining depth was shallow, it was possible to supply cutting fluid to the tool by external nozzle injection using an external oil supply method even when the spindle rotation was fast. However, when the processing depth is deep, there is a problem that the cutting fluid cannot be sufficiently supplied to the tool blade portion.
On the other hand, in the internal oil supply method, it is possible to supply the cutting fluid to the tool blade even when the machining depth is deep. For example, in the method of supplying from the cutting fluid supply hole in the tool tip as in Patent Document 1, the cutting fluid can be supplied even during high-speed rotation. However, since there are few standard tools with a small diameter tool φ3 or less, there is a problem that the tool itself is expensive. In addition, in the case of a small diameter tool, there is a problem that chips at the time of cutting are clogged in the cutting fluid supply hole, and the cutting fluid is not supplied, leading to a chipping of the tool.
Further, in the method of providing a cutting fluid supply hole in the tool holder as in Patent Document 2 and supplying the cutting fluid from this hole, the cutting fluid from the cutting fluid supply hole spreads by centrifugal force during high-speed rotation. There has been a problem that the cutting fluid is not supplied to the blade portion of the tool, leading to tool breakage and reduced life.
Further, in the method of providing the cutting fluid supply groove parallel to the shaft on the outer periphery of the tool shank as in Patent Document 3, there is a problem that the groove material is difficult and the cost is high because the tool material is a high hardness material. .

  The present invention has been made to solve the problem, and a tool holder that can reliably supply cutting fluid to the cutting portion even when machining at high speed without performing special machining on the tool itself. The purpose is to provide.

  A tool holder according to the present invention is a tool holder that holds a cutting tool on a rotating shaft and supplies a cutting fluid to a cutting portion that is cut by the cutting tool, and a cutting fluid path through which the cutting fluid passes. A cutting fluid supply hole connected to the cutting fluid path and ejecting the cutting fluid, wherein the cutting fluid supply hole is configured by two or more cutting fluid supply holes having different distances from the rotating shaft. did.

  According to the present invention, even when cutting at high speed, the cutting fluid can be supplied to the cutting portion, so that the tool can be effectively cooled, and the tool is lost and its life is reduced. Can be prevented.

Embodiment 1 FIG.
Hereinafter, embodiments of a tool holder according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a tool holder 2 used in the machine tool according to the first embodiment. In FIG. 1, the tool holder 2 includes a collet 3 inside, and the collet 3 holds the tool T on the rotation axis.
As shown in FIG. 1, the cutting fluid C supplied through the cutting fluid path 22 provided at the center of the tool holder 2 is a groove of a tapered collet (cutting fluid) fitted in the tool holder body 2. It passes through the path 22) and is sprayed from the cutting fluid supply holes 12a and 12b opened in the cutting fluid supply plate 11 fixed to the tip of the tool holder body 2. The cutting fluid supply plate 11 can be exchanged according to the thickness and shape of the tool.

FIG. 2 is an example of an external view of the cutting fluid supply plate 11 of the first embodiment. FIG. 2A is an example of a side view of the cutting fluid supply plate 11 seen from the lateral direction, and FIG. 2B is a top view seen from the upper direction.
The cutting fluid supply plate 11 has a circular shape as shown in FIG. 2B, and a tool insertion hole 23 through which a tool T such as an end mill held on the rotating shaft passes is formed in the center portion thereof. The tool insertion hole 23 has a circular shape with the tool rotation axis of the tool holder 2 as the center.
The tool insertion hole 23 is generally formed with a comma several mm larger than the outer diameter of the tool T, and the inner periphery 23a of the tool insertion hole 23 and the outer periphery of the tool T are formed so as to have a slight gap.
Further, first cutting fluid supply holes 12a are formed in the inner wall 23b of the tool insertion hole 23 at equal intervals in the circumferential direction or at arbitrary positions along the direction in which the cutting fluid C flows.

The cutting fluid supply plate 11 according to Embodiment 1 of the present invention further includes a second cutting fluid supply hole 12b outside the tool insertion hole 23 provided with the first cutting fluid supply hole 12a. That is, when the cutting fluid supply plate 11 is viewed from above, the second cutting fluid supply hole 12b is provided at a position longer than the distance from the rotation axis to the first cutting fluid supply hole 12a.
In FIG. 2B, the second cutting fluid supply holes 12 b are opened at three positions on the concentric circles (broken line portions) that are outside the tool insertion hole 23 and have a diameter larger than that of the tool insertion hole 23. ing. The cutting fluid C is sprayed onto the tool T through the second cutting fluid supply hole 12b together with the first cutting fluid supply hole 12a.
The cutting fluid supply plate 11 shown in FIG. 2B is fixed to the tool holder 2 by, for example, screwing provided on the outer periphery of the plate.

FIG. 4 is a view showing an example of a cutting fluid supply plate 51 that has been conventionally used. A circular tool insertion hole 53 centering on the rotation axis and a cutting fluid supply hole 52 formed along the direction in which the cutting fluid C flows in the inner wall of the tool insertion hole 53 are formed. The cutting fluid C mainly passes through the cutting fluid supply hole 52 and is sprayed to the cutting portion of the tool T.
As described above, in the cutting fluid supply plate 51 conventionally used, the cutting fluid supply hole 52 is only formed on the circumference of one circle. The first cutting fluid supply hole 12a and the second cutting fluid supply hole 12b are not provided on the circumference of the circle.
In some cases, an O-ring, which is a seal member, may be inserted to prevent the cutting fluid C from being ejected from the gap between the tool insertion hole 53 and the outer periphery of the tool T. In this case, the cutting fluid C is sprayed to the tool T only through the cutting fluid supply hole 52.

Next, the fact that the cutting fluid C can be reliably supplied to the cutting portion by using the tool holder 2 of the present invention will be described below with reference to the drawings.
In FIG. 3, the cutting fluid supply plate 11 of the first embodiment is used, and the cutting fluid is injected from the first cutting fluid supply hole 12a and the second cutting fluid supply hole 12b opened in the cutting fluid supply plate 11. This shows how the cutting fluid is sprayed. Here, the cutting fluid C sprayed from the gap between the tool insertion hole 23 and the outer periphery of the tool T is omitted.
On the other hand, FIG. 5 uses the conventional cutting fluid supply plate 51 shown in FIG. 4 to perform cutting when the cutting fluid is ejected from the first cutting fluid supply hole 12 a opened in the cutting fluid supply plate 51. This shows how the liquid is jetted. As in the example of FIG. 3, the cutting fluid C injected from the gap between the tool insertion hole 52 and the tool T outer periphery is omitted.

  FIG. 3A shows the state of injection of the cutting fluid C when the cutting fluid supply plate 11 according to the first embodiment is used and the machine tool rotates at a relatively low speed of about several thousand (rpm). Is. At the time of low speed rotation, the cutting fluid C sprayed from the first cutting fluid supply hole 12a does not spread so much even if the centrifugal force due to rotation acts, and reaches the tip of the cutting edge (working portion) of the tool T to lubricate the tool. Cooling and chip discharge are performed. At this time, the cutting fluid C is also injected from the second cutting fluid supply hole 12b. However, since the cutting fluid C is rotated at a low speed, the cutting fluid C does not spread so much and is injected around the machining portion.

On the other hand, FIG. 5A shows a case where the conventional cutting fluid supply plate 51 is used. Similarly, the cutting fluid C is injected at a relatively low speed of about several thousand (rpm) of the machine tool. At this time, the cutting fluid C sprayed from the first cutting fluid supply hole 52 does not spread so much even if the centrifugal force due to rotation acts, and is applied to the tip of the cutting edge of the tool T (processing portion). The tool is lubricated, cooled, and chips are discharged.

FIG. 5B shows a state in which the cutting fluid C is injected when the conventional cutting fluid supply plate 51 is used and the machine tool rotates at a high speed (for example, 8000 (rpm) or more). Is.
If it rotates at high speed, a centrifugal force will act on the cutting fluid C injected from the cutting fluid supply hole 52, and the cutting fluid C will spread. In this state, the cutting fluid C does not hit the cutting edge tip (working portion) of the tool T, the tool is not lubricated, cooled, and chips are not discharged, and the cutting edge is lost or the tool wears quickly. .

On the other hand, FIG. 3B shows the state of jetting the cutting fluid C when the cutting fluid supply plate 11 of the first embodiment is used and the rotation speed of the machine tool is high-speed rotation (for example, 8000 (rpm) or more). It represents.
Centrifugal force acts on the cutting fluid C sprayed from the second cutting fluid supply hole 12b opened outside the cutting fluid supply plate, and the spray is spread and sprayed.
However, the cutting fluid C sprayed from the inner second cutting fluid supply hole 12b becomes a curtain state of the cutting fluid C from the outer second cutting fluid supply hole 12b, and the action of centrifugal force is reduced. It flows straight without spreading outside as in the past.
In this way, the cutting fluid supply holes are formed in the inner and outer doubles, and the cutting fluid is supplied from both the inner and outer holes, so that the cutting fluid sprayed from the inner holes can be obtained even during high-speed rotation. Can flow straight.
Thereby, even at the time of high-speed rotation, the cutting fluid C can reach the cutting edge tip (working portion) of the tool T, and the tool can be lubricated, cooled, and chips can be discharged.

FIG. 6 schematically shows a region where cutting can be performed when the conventional cutting fluid supply plate 51 is used and when the cutting fluid supply plate of the present invention is used.
In the conventional cutting fluid supply plate, even if the cutting fluid discharge pressure is increased to 7 (MPa), the cutting fluid spreads and cutting cannot be performed when the spindle rotation speed becomes faster than 8000 (rpm). On the other hand, when the cutting fluid supply plate of the present invention is used, if the cutting fluid discharge pressure is increased to 7 (MPa), stable cutting can be performed even if the spindle speed is 20000 (rpm). It shows that there is.

As described above, in Embodiment 1 of the present invention, the cutting fluid supply plate attached to the cutting fluid injection portion of the tool holder main body has a double circumference on the inner side and the outer side at different distances from the center (spindle rotation axis). A cutting fluid supply hole was opened on the top, and the cutting fluid was supplied from both the inner and outer cutting fluid supply holes.
As a result, even when the spindle is rotated at a high speed (for example, 8000 (rpm) or more), the cutting fluid C supplied from the inner cutting fluid supply hole can flow straight, and the cutting fluid is cut. It is possible to reliably supply the processed portion.

In the present embodiment, the cutting fluid supply plate 11 has a flat plate shape as shown in FIG. 2 and is attached to the tip of the tool holder 2. However, the shape of the plate and the attachment to the tool holder are described. The method is not limited to this.
FIG. 7 shows an example of another cutting fluid supply plate 11. The cutting fluid supply plate 11 has a step having a thick central portion and a thin peripheral thickness. A first cutting fluid supply hole 12a and a second cutting fluid supply hole 12b are provided.
The tool holder 2 uses an L-shaped fixing bracket as shown in FIG. 7 (b) to supply a cutting fluid by pressing a thin portion around the cutting fluid supply plate 11 with the L-shaped fixing bracket. The plate 11 is fixed, and the cutting fluid supply plate 11 having such a shape may be used.

  As another example of the cutting fluid supply plate 11, as shown in FIG. 8, the cutting fluid supply plate 11 may have an inclined portion around it. The first cutting fluid supply hole 12 a and the second cutting fluid supply hole 12 b are provided in a thick portion at the center of the cutting fluid supply plate 11. The tool holder 2 is fixed to the cutting fluid supply plate 11 by a fixed metal fitting as shown in FIG. 8B so that the inclined portion of the cutting fluid supply plate 11 is pressed by the fixing metal fitting. The cutting fluid supply plate 11 having such a shape may be used.

Embodiment 2. FIG.
In the first embodiment, the example in which the cutting fluid supply plate is attached to the cutting fluid injection port of the tool holder and the double cutting fluid supply holes are formed in the cutting fluid supply plate has been described. In the second embodiment, an example of an integrated tool holder without a cutting fluid supply plate will be described. In addition, the same number is attached | subjected to the structure similar to Embodiment 1, and description is abbreviate | omitted.

  FIG. 9 is a diagram illustrating an example of the tool holder according to the second embodiment. A taper collet 21 is fitted in the tool holder 2, and the taper collet 21 grips the tool T and performs processing. The cutting fluid C is ejected from the tip of the tapered collet 21 through the tool holder body 2 and the groove (cutting fluid path) in the tapered collet 21.

  FIG. 10 is a view showing the shape of the tip of the tapered collet 21. FIG. 10A is a longitudinal sectional view, and FIG. 10B is a transverse sectional view of the tip of the tapered collet 21 (a plane including A-A ′ in FIG. 10A).

In FIG. 10A, a first cutting fluid path 22a and a second cutting fluid path 22b are formed at the tip of the tapered collet 21 along the direction in which the cutting fluid C flows. FIG. 10B is a bottom view of the tapered collet 21 as viewed from below. The first cutting fluid is separated from the first cutting fluid supply hole 12a (connected to the first cutting fluid path 22a). A second cutting fluid supply hole 12b (connected to the second cutting fluid path 22b) is formed inside the supply hole 12a. In the example of FIG. 10B, the second cutting fluid supply hole 12 b is formed in a part of the inner wall of the tool insertion hole 23.
As described above, in the second embodiment, the first cutting fluid supply hole 12a and the second cutting fluid supply hole 12b are formed directly at the tip of the tapered collet 21, and these holes are formed in the internal cutting fluid. It is connected to the path 22.

FIG. 11 is a view showing the shape of a cutting fluid supply hole formed at the tip of a conventional tapered collet 51. In the conventional tapered collet 51, cutting fluid supply holes 52 are formed at three locations on the circumference outside the tool insertion hole 53.
When the conventional tapered collet shown in FIG. 11 is used, the spread of the cutting fluid C sprayed from the cutting fluid supply hole 52 during a relatively low speed rotation of the machine tool with a tool rotational speed of about several thousand (rpm). However, it spreads outward due to centrifugal force during high-speed rotation.

In the second embodiment of the present invention, as shown in FIG. 10B, the second cutting fluid supply hole b is formed along the inner wall of the tool insertion hole 23 inside the first cutting fluid supply hole 12a. I tried to do it.
Cutting is performed by supplying cutting fluid from the cutting fluid supply holes arranged on the circumference of the double circle of the first cutting fluid supply hole 12a on the outside and the second cutting fluid supply hole 12b on the inside thereof. Then, the cutting fluid C sprayed from the outer cutting supply hole is in a curtain state, and the cutting fluid C sprayed from the inner V-shaped first cutting fluid supply hole 12a, even during high-speed rotation, It flows straight.

As described above, the tool holder of the second embodiment is an integrated tool holder without a cutting fluid supply plate, and is provided with double cutting fluid paths 22a and 22b in a collet or the like in the tool holder, The cutting fluid C was supplied from the first cutting fluid supply hole 12a and the second cutting fluid supply hole 12b arranged on the circumference of the outer double circle.
Thereby, even when the tool rotates at a high speed, the cutting fluid C flows straight from the inner cutting supply hole, and the cutting fluid can be supplied to the processing portion.

  In FIG. 10, the inner second cutting fluid supply hole 12b is V-shaped, but may be semicircular, for example, and the effects of the invention are achieved regardless of the shape of the cutting fluid supply hole itself. .

Embodiment 3 FIG.
In the first and second embodiments, the cutting fluid supply hole located inside is formed along the inner wall of the tool insertion hole. However, in the third embodiment, the cutting fluid supply hole located inside is defined as the tool insertion hole. It is formed outside the tool insertion hole, not along the inner wall.
FIG. 12 shows an arrangement example of the cutting fluid supply holes of the third embodiment. In FIG. 12, a first cutting supply hole 31a is provided on the outer circumference of the cutting fluid supply hole 23, and a second cutting fluid supply hole 31b is provided on the outer circumference of the circle. .
Also in this case, when the cutting fluid is supplied from each of the cutting fluid supply holes and the cutting is performed, the cutting fluid C sprayed from the second cutting fluid supply hole 31b is in a curtain state, and the tool is rotated at a high speed. Even so, the cutting fluid C sprayed from the first cutting fluid supply hole 12a flows straight and can effectively cool the tool of the cutting portion.
Further, the cutting fluid supply hole may be opened in the cutting fluid supply plate as in the first embodiment, or may be opened in the collet in the tool holder as shown in the second embodiment.

Embodiment 4 FIG.
In Embodiments 1 to 3, the cutting fluid supply hole is formed on the circumference of the double circle, but the cutting fluid supply hole may be formed on the circumference of the triple circle.
FIG. 13 is a view showing the shape of the cutting fluid supply hole of the fourth embodiment. Thus, the cutting fluid supply hole may be formed on the circumference of the triple circle.
It should be noted that the same effect can be obtained as long as it is n-fold (n ≧ 2).

Embodiment 5 FIG.
In the first to fourth embodiments, the number of cutting fluid supply holes opened on the circumference of each circle is the same, but is not limited to the same number.
FIGS. 14A and 14B are views showing the shape of the cutting fluid supply hole of the fifth embodiment. Thus, the number of the first cutting fluid supply holes 31a and the number of the second cutting fluid supply holes 31b may be different. As shown in FIG. 14B, the number of cutting fluid supply holes on the circumference may be one.

Embodiment 6 FIG.
In the first to fifth embodiments, the cutting fluid supply holes are arranged on the circumference of each circle, but are not limited to the circumference.
FIG. 15 is a view showing the arrangement of the cutting fluid supply holes of the sixth embodiment. In the first to fifth embodiments, the cutting fluid supply hole is formed on the circumference of each circle. However, it is not always necessary to be on the circumference as shown in FIG. It is only necessary that the cutting fluid supply holes are formed at positions from the rotation shaft that are determined to be double on the outside.
It should be noted that the present invention is not limited to the double, and the same effect can be obtained as long as the n-fold (n ≧ 2).

Embodiment 7 FIG.
In the first to sixth embodiments, the shape of the cutting fluid supply hole is not limited to a circle and may be a rectangle. In addition, the same effect can be obtained in any of an ellipse, a V-shaped groove, and a rectangle.

It is a longitudinal cross-sectional view of the state which attached the tool to the tool holder which concerns on Embodiment 1. FIG. 2 is an external view of a cutting fluid supply plate according to Embodiment 1. FIG. It is a figure explaining the spread of the cutting fluid radiate | emitted from the tool holder which concerns on Embodiment 1 at the time of (a) low speed rotation and (b) high speed rotation. It is an external view of the conventional cutting fluid supply plate. It is a figure explaining the breadth of the cutting fluid radiate | emitted from the conventional tool holder at the time of (a) low speed rotation and (b) high speed rotation. It is a figure which shows the use range of the tool holder of this invention. It is an example of the state which attached the other cutting fluid supply plate which concerns on Embodiment 1 to the tool holder. It is an example of the state which attached the other cutting fluid supply plate which concerns on Embodiment 1 to the tool holder. It is a longitudinal cross-sectional view of the tool holder which concerns on Embodiment 2. FIG. It is a longitudinal cross-sectional view of the taper type collet concerning Embodiment 2, and an example of the hole shape opened at the taper type collet tip. It is an example of the hole shape of the conventional taper type collet tip. FIG. 6 is a view showing an arrangement of cutting fluid supply holes according to a third embodiment. It is the figure which showed arrangement | positioning of the cutting fluid supply hole which concerns on Embodiment 4. FIG. FIG. 10 is a diagram showing an arrangement of cutting fluid supply holes according to a fifth embodiment. FIG. 10 is a diagram showing an arrangement of cutting fluid supply holes according to a sixth embodiment.

Explanation of symbols

  2 Tool holder body, 11 Cutting fluid supply plate, 12 Cutting fluid supply hole, 12a First cutting fluid supply hole, 12b Second cutting fluid supply hole, 19 L-shaped fixing bracket, 21 Tapered collet, 22 Cutting Fluid path, 23 Tool insertion hole, 30aL Cutting fluid supplied from first cutting fluid supply hole during low-speed rotation, 30bL Cutting fluid supplied from second cutting fluid supply hole during low-speed rotation, 30aH First during high-speed rotation Cutting fluid supplied from the cutting fluid supply hole, 30bH Cutting fluid supplied from the second cutting fluid supply hole during high-speed rotation, 50 workpieces, 51 Conventional cutting fluid supply plate, 52 Cutting fluid supply hole, 53 Tool insertion Hole, 70L Cutting fluid supplied from cutting fluid supply hole during low-speed rotation, Cutting fluid supplied from cutting fluid supply hole during high-speed rotation, c Cutting fluid, T tool.

Claims (6)

A tool holder for holding a cutting tool on a rotating shaft and supplying a cutting fluid to a cutting part cut by the cutting tool,
A cutting fluid path for passing the cutting fluid;
A cutting fluid supply hole connected to the cutting fluid path and from which the cutting fluid is ejected,
The tool holder, wherein the cutting fluid supply hole is composed of two or more cutting fluid supply holes having different distances from the rotating shaft. The tool holder according to claim 1, wherein the cutting fluid supply hole is disposed on a circumference of two or more circles having different diameters around the rotation axis. An exchangeable cutting fluid supply plate is provided at the end of the cutting fluid path,
The tool holder according to claim 1, wherein the cutting fluid supply hole is formed in the cutting fluid supply plate. A cutting fluid supply plate for a tool holder that is attached to one end of a cutting fluid path formed inside a tool holder that holds a cutting tool on a rotating shaft,
A tool insertion hole for inserting the cutting tool;
A cutting fluid supply hole through which cutting fluid passes through the cutting fluid path;
With
The cutting fluid supply plate for a tool holder, wherein the cutting fluid supply hole is composed of two or more cutting fluid supply holes having different distances from the rotating shaft. A cutting method of cutting while supplying a cutting fluid to a cutting portion using a cutting tool,
A cutting method, wherein the cutting tool performs a cutting process while ejecting the cutting liquid from two or more cutting liquid supply holes having different distances from a rotation axis of the cutting tool. 6. The cutting method according to claim 5, wherein the cutting tool is rotated at a high speed of 8,000 (rpm) or more for cutting.

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