JP2022077830A - Tool holder and machine tool - Google Patents

Abstract

To provide a tool holder and a machine tool, which can stably obtain a high vibration suppression effect with low costs and general purpose.SOLUTION: In a tool holder 1, a tool insertion hole 2 includes: a tool fixing section 2A which can fix a tool 10 with a tool fixing bolt with fixing force to regulate relative movement of the tool 10 with respect to the tool holder 1 when vibration is caused by machining; and a tool contact section 2B which can hold the tool 10 with fixing force lower than that of the tool fixing section 2A and can allow relative movement of the tool 10 with respect to the tool holder 1 when vibration is caused by machining.SELECTED DRAWING: Figure 3

Description

The present invention relates to a tool holder having a function of suppressing vibration generated in a tool during machining in a machine tool that performs machining while moving the tool and the work relative to each other, and a machine tool provided with the tool holder. ..

In a machine tool in which a tool is supported by a rotatable work and the tool and the work are relatively moved while being fed to machine the work, the tool may be used with a large protrusion amount as in boring. A tool holder for holding such a tool is known to be fixed by inserting a tool into a tool insertion hole having a split structure and bolting it (see Non-Patent Document 1).
FIG. 11 is a schematic configuration diagram showing the configuration of the conventional grind tool holder 30. For convenience, the tip side (tip 11 side) of the tool 10 in FIG. 11 will be described as the front side, and the upper side of the tool holder 30 will be described as the upper side. FIG. 12 is a schematic configuration diagram showing the configuration of the grind tool holder 30 in the cross section CC of FIG. 11 (cross section in the plane defined in the front-back and up-down directions). In this case, it is applied to a lathe 20 having a swivel turret 21.
The split tool holder 30 has a slit 32 that is connected to the tool insertion hole 31 having a diameter equal to or smaller than the diameter of the tool 10 and the outside of the tool insertion hole 31 and the split tool holder 30 and is opened through the tool 10 in the longitudinal direction. Have. Further, in order to fix the holder fixing bolt 3 for fixing the grind tool holder 30 to the mounting surface 22 on the outer periphery of the swivel turret 21 and the angular position of the tool 10 in the circumferential direction with respect to the grind tool holder 30. The tool phase fixing bolt 33 and the holder expanding bolt 6 for increasing the diameter of the tool insertion hole 31 so that the tool 10 can be inserted are provided.
When setting the tool, the holder expansion bolt 6 is tightened and pressed against the lower surface of the slit 32 to increase the diameter of the tool insertion hole 31 and insert the tool 10 from the rear end. Next, the tool 10 is adjusted to a desired protrusion length and angle position, and the angle of the tool 10 is fixed by using the tool phase fixing bolt 33. Finally, after loosening the holder expansion bolt 6, the holder fixing bolt 3 is tightened to fix the split tool holder 30 to the swivel turret 21 and increase the contact pressure with respect to the tool 10 to increase the contact pressure of the tool 10. To fix.

When a tool 10 having a large protrusion amount is used, a large machining vibration (hereinafter referred to as chattering) may occur due to a decrease in tool rigidity, which causes problems such as a defect in the tool 10 and a defect in machined surface quality. In the split tool holder 30, if the holding rigidity by the tool phase fixing bolt 33 and the holder fixing bolt 3 is improved, a certain vibration suppressing effect can be expected, but there is a limit to the improvement of the holding structure.
Therefore, as a conventional technique for effectively suppressing chatter, Patent Document 1 discloses an invention in which a damping structure (vibration damping piece) is provided in a tool to improve vibration damping properties. Further, Patent Document 2 discloses an invention in which the rotation speed of the spindle is continuously changed by control.

"Ultimate anti-vibration tool" Sandvik Coromant Company, page 4, "How to clamp the bite", [Search on October 19, 2nd year of Reiwa], Internet <URL: https://www.sandvik.coromant .com / SiteCollectionDocuments / downloads / jp / brochures / CG-036J-R2_SilentTools.pdf ＞

Japanese Unexamined Patent Publication No. 2005-177973 Japanese Unexamined Patent Publication No. 49-105277

However, while the method of Patent Document 1 can obtain high damping property, it is expensive because it is necessary to provide a damping structure for each tool, and there is a problem in versatility. Further, while the method of Patent Document 2 can obtain a vibration suppressing effect in all tools, there is a problem that effective control cannot be performed at high speed rotation due to restrictions on motor performance and the like.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a tool holder and a machine tool that can stably obtain a high vibration suppression effect while being low-cost and versatile. be.

In order to achieve the above object, the first aspect of the present invention is a tool holder provided in a machine tool, having a tool insertion hole, and fixing a tool inserted in the tool insertion hole by a fixing means. There,
The tool insertion hole includes a tool fixing portion capable of fixing the tool by the fixing means with a fixing force that regulates the relative movement of the tool to the tool holder when vibration due to machining occurs.
It includes a tool contact portion that can hold the tool with a lower fixing force than the tool fixing portion and can allow the tool to move relative to the tool holder when vibration due to the machining occurs. It is a feature.
Another aspect of the first invention is characterized in that, in the above configuration, the tool contact portion is provided on the tip end side of the tool with respect to the tool fixing portion.
Another aspect of the first invention is characterized in that, in the above configuration, the fixing means is a tool fixing bolt for pressing and fixing the tool to the tool insertion hole by screwing into the tool holder.
Another aspect of the first invention is characterized in that, in the above configuration, at least a slit communicating with the tool contact portion is formed along the axial direction of the tool insertion hole.
Another aspect of the first invention is characterized in that, in the above configuration, the slit is open to the outside.
Another aspect of the first invention is characterized in that, in the above configuration, the tool contact portion is provided with an expansion mechanism capable of expanding in the radial direction.
Another aspect of the first invention is characterized in that, in the above configuration, the cross-sectional shape of the tool contact portion is equal to or smaller than the cross-sectional shape of the tool.
In order to achieve the above object, the second invention of the present invention is a machine tool, characterized in that it includes the tool holder according to any one of the first inventions.

According to the present invention, it is possible to stably impart high damping property to all tools with the same manufacturing cost as the existing grinding tool holder and the same setting man-hours. Therefore, it is possible to stably obtain a high vibration suppression effect and realize highly efficient processing while being low cost and versatile.

It is a schematic block diagram which shows the structure of a tool holder. It is a schematic block diagram which shows the structure of the tool holder in the cross section AA of FIG. It is a schematic block diagram which shows the structure of the tool holder in the cross section BB of FIG. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the modification example of a tool holder. It is a schematic block diagram which shows the structure of the existing tool holder. It is a schematic block diagram which shows the structure of the tool holder in the cross section CC of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing the configuration of the tool holder 1. For convenience, the tip side (tip 11 side) of the tool 10 in FIG. 1 will be described as the front side, and the upper side of the tool holder 1 will be described as the upper side. FIG. 2 is a schematic configuration diagram of a cross section AA of FIG. 1 (a cross section in a plane defined in the front-back and up-down directions). FIG. 3 is a schematic configuration diagram of a cross section BB (cross section in a plane defined in the front-back and left-right directions) of FIG. In this example, the tool holder 1 is applied to the swivel turret 21 of the lathe 20 which is an example of a machine tool. The tool 10 has a substantially circular cross section and is provided with a tip 11 at the tip.
The tool holder 1 has a block shape fixed to the mounting surface 22 on the outer periphery of the swivel turret 21. The tool holder 1 is formed with a tool insertion hole 2 through which the tool 10 is inserted from the rear end in the front-rear direction. On the left and right sides of the tool holder 1 with the tool insertion hole 2 interposed therebetween, three holder fixing bolts 3, 3, ... For fixing the tool holder 1 to the mounting surface 22 are arranged in the front-rear direction.
The tool insertion hole 2 has a tool fixing portion 2A on the rear side and a tool contact portion 2B on the front side coaxially. The tool fixing portion 2A is formed with an inner diameter that is equal to or larger than the diameter of the tool 10. The tool contact portion 2B is formed with an inner diameter that is equal to or smaller than the diameter of the tool 10.

Two tool fixing bolts 4 and 4 for pressing and fixing the tool 10 inserted in the tool insertion hole 2 from above are arranged in the front and rear of the tool holder 1 on the upper side of the tool fixing portion 2A.
On the right side of the front portion of the tool holder 1, a slit 5 for communicating the tool contact portion 2B with the outside of the tool holder 1 is formed in parallel with the mounting surface 22. On the upper side of the slit 5, the tool holder 1 is provided with a holder expansion bolt 6 (expansion mechanism) capable of expanding the inner diameter of the tool contact portion 2B by pressing the lower surface of the slit 5 by a screwing operation. There is. However, the slit 5 and the holder expansion bolt 6 may be on the left side of the front portion of the tool holder 1.

In the tool holder 1 configured as described above, when setting the tool, the holder fixing bolt 3 is tightened to fix the tool holder 1 to the mounting surface 22 of the swivel turret 21. Next, the holder expansion bolt 6 is tightened and pressed against the lower surface of the slit 5 to widen the diameter of the tool contact portion 2B, and the tool 10 is inserted into the tool insertion hole 2 from the rear end. Subsequently, after adjusting the tool 10 to a desired protrusion length and angle position, the tool fixing bolt 4 is tightened to fix the rear end of the tool 10 in the tool fixing portion 2A. Finally, the holder expansion bolt 6 is loosened to bring the tool contact portion 2B into contact with the tool 10.

When turning is performed by the tool 10 fixed to the tool holder 1 in this way, when machining vibration occurs, the tool holder 1 and the tool 10 are held and fixed by a high fixing force that does not move relative to each other in the tool fixing portion 2A. The tool contact portion 2B makes contact with a low fixing force that causes relative movement. Further, since the tool contact portion 2B is not tightened with bolts, the contact pressure is determined by the tightening allowance between the tool 10 and the tool insertion hole 2 regardless of the setting method of the operator, and performance variation can be suppressed. can. As a result, during machining, the position of the tool 10 does not change due to the firm fixing on the rear side of the tool holder 1, stable friction damping occurs in the contact region on the front side, and machining vibration can be suppressed. ..

As described above, according to the tool holder 1 and the lathe 20 of the above-described embodiment, the tool insertion hole 2 tools the tool 10 with a fixing force that regulates the relative movement of the tool 10 with respect to the tool holder 1 when vibration due to machining occurs. The tool fixing portion 2A that can be fixed by the fixing bolt 4 (fixing means) and the tool 10 that can hold the tool 10 with a lower fixing force than the tool fixing portion 2A, and the tool 10 with respect to the tool holder 1 when vibration due to machining occurs. It includes a tool contact portion 2B that allows relative movement.
Therefore, it is possible to stably provide high damping property to all tools with the same manufacturing cost as the existing grinding tool holder and the same setting man-hours. Therefore, it is possible to stably obtain a high vibration suppression effect and realize highly efficient processing while being low cost and versatile.

An example of the change will be described below.
Like the tool holder 1A shown in FIG. 4, in order to improve the openness of the tool insertion hole 2, it does not open to the outside by communicating with the tool contact portion 2B on the opposite side of the slit 5 sandwiching the tool contact portion 2B. The slit 5a may be provided in the front-rear direction. A plurality of slits that do not open to the outside may be provided.
The tool holder 1B shown in FIG. 5 is also provided with a slit 5b in the front-rear direction on the upper side of the tool contact portion 2B, which communicates with the tool contact portion 2B and opens to the outside. In this way, the number of slits may be increased.
The tool holder 1C shown in FIG. 6 forms a continuous left-right slit 5c at the rear end of the slit 5 in addition to the front-rear direction.
The tool holder 1D shown in FIG. 7 is a split die 7 in which the forming portion of the tool contact portion 2B is separated on the upper side of the slit 5 in order to facilitate the manufacture of the tool holder 1D, and the split die 7 is assembled with a bolt or the like. The tool holder 1D is formed by. The number of split molds may be increased.

In the tool holder 1E shown in FIG. 8, in addition to the slit 5a of FIG. 4, a slit 5d parallel to the slit 5a is provided on the outer surface in the front-rear direction. Even if the slit 5d is provided on the outside of the tool holder 1E in this way, the openness of the tool insertion hole 2 can be improved, and the force for holding the tool 10 can be adjusted. In addition, in FIG. 8, the slit 5a may be omitted.
Unlike FIG. 6, the tool holder 1F shown in FIG. 9 has a slit 5e in the left-right direction formed on the upper surface thereof, which is not continuous with the rear end of the slit 5. As shown in FIGS. 8 and 9, the direction of the slit formed on the outside of the tool holder can be changed as appropriate.
In the tool holder 1G shown in FIG. 10, the slit 5 that communicates the tool contact portion 2B with the outside of the tool holder 1G is not parallel to the mounting surface 22 but is inclined downward so as to approach the mounting surface 22 toward the rear. Is forming. It is also possible to change the angle of the slit 5 in this way. This slope may be upward instead of downward.
Each modification example can be combined as appropriate.

On the other hand, in the above embodiment, the slit is provided only on the front side (tool contact portion side) of the tool holder, but the hole diameter of the tool contact portion on the front side is made larger than the hole diameter of the tool fixing portion on the rear side. Above, a slit may be provided over the entire length of the tool insertion hole as in the existing grind tool holder. In this case as well, by tightening the tool fixing portion with the tool fixing bolt, it is possible to form a tool contact portion on the front side where the tool is held with a low fixing force that allows the tool and the tool holder to move relative to each other.
In the above embodiment, the slit that opens to the outside of the tool holder is provided, but the tool insertion hole may be provided with only a slit that does not open to the outside of the tool holder to cause the same expansion deformation.
In the above embodiment, the holder expansion bolt is tightened to increase the diameter of the tool insertion hole, and then the tool is inserted, and then the holder expansion bolt is loosened to bring the tool into contact. After making the diameter larger than the diameter of the tool, the tool insertion hole may be made smaller by tightening a bolt or the like to make contact.
In the above embodiment, the tool holder is deformed by using the holder expansion bolt, but it goes without saying that the tool holder may be deformed by using a spring, a lever, or the like.

In the above embodiment, the tool fixing portion and the tool contact portion are formed coaxially, but they may be formed so that their centers are offset from each other. The hole diameter between the tool fixing portion and the tool contact portion and the cross-sectional shape of both can be changed as appropriate. In particular, the cross-sectional shape is not limited to a circle, but can be selected according to the cross-sectional shape of the tool such as an ellipse or a polygon.
In the above embodiment, the tool fixing portion is arranged on the rear side and the tool contact portion is arranged on the front side, but they may be arranged upside down. The tool fixing portion may be arranged in the middle portion instead of the rear portion of the tool insertion hole, and the tool contact portion may be arranged on the front side or the rear side thereof.
In addition, the tool holder of the present invention can be applied to machine tools other than lathes.

1,1A ~ 1G ・ ・ Tool holder, 2 ・ ・ Tool insertion hole, 2A ・ ・ Tool fixing part, 2B ・ ・ Tool contact part, 3 ・ ・ Holder fixing bolt, 4 ・ ・ Tool fixing bolt, 5,5a ~ 5e ... Slit, 6 ... Holder expansion bolt, 7 ... Split type, 10 ... Tool, 20 ... Lathe, 21 ... Swivel turret, 22 ... Mounting surface.

Claims (8)

A tool holder provided in a machine tool, having a tool insertion hole, and fixing a tool inserted in the tool insertion hole by a fixing means.
The tool insertion hole includes a tool fixing portion capable of fixing the tool by the fixing means with a fixing force that regulates the relative movement of the tool to the tool holder when vibration due to machining occurs.
It includes a tool contact portion that can hold the tool with a lower fixing force than the tool fixing portion and can allow the tool to move relative to the tool holder when vibration due to the machining occurs. Characterized tool holder. The tool holder according to claim 1, wherein the tool contact portion is provided on the tip end side of the tool with respect to the tool fixing portion. The tool holder according to claim 1 or 2, wherein the fixing means is a tool fixing bolt that presses and fixes the tool to the tool insertion hole by screwing into the tool holder. The tool holder according to any one of claims 1 to 3, wherein at least a slit communicating with the tool contact portion is formed along the axial direction of the tool insertion hole. The tool holder according to claim 4, wherein the slit is open to the outside. The tool holder according to claim 5, further comprising an expansion mechanism capable of expanding the tool contact portion in the radial direction. The tool holder according to any one of claims 1 to 6, wherein the cross-sectional shape of the tool contact portion is equal to or smaller than the cross-sectional shape of the tool. A machine tool comprising the tool holder according to any one of claims 1 to 7.

Images