JP2001300828A - Tool holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tool holder capable of preventing heat generated by a main spindle of a machine tool from being transmitted to the tool holder. SOLUTION: This tool holder 11 installed on the main spindle 3 of the machine tool is provided with the constitution for restraining the heat generated from the main spindle 3 from being transmitted to the tool holder 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holder for mounting a cutting tool on a spindle of a machine tool. The function of transmitting to the holder side and extending the tool holder due to thermal expansion reduces the accuracy of the workpiece in the axial direction (Z-axis direction), and also has the function of preventing a step from being formed on the workpiece. Tool holder provided.

[0002]

2. Description of the Related Art Conventionally, a tool holder used for a cutting process transmits heat generated by the rotation speed and rotation of a main spindle of a machine tool to the cutting tool, and also generates cutting between the cutting tool and a workpiece. It also had the role of a heat exchanger, releasing heat to the main spindle through the tool holder.

[0003] Therefore, the main spindle is 10,000 m
In the rotation range less than in ^-1 , heat generation is not so high and the influence on accuracy is small.Therefore, the tool holder side has a configuration to actively prevent the heat of the spindle spindle from being transmitted to the tool holder side. I didn't let it.

[0004] In recent years, with the spread of high-speed cutting technology, as the speed of the spindle of a machine tool increases, the spindle itself generates heat, and the heat is transmitted to a tool holder and a tool. The displacement in the axial direction has caused a problem that the accuracy of the workpiece in the axial direction (Z-axis direction) cannot be secured. In addition, the temperature at which heat is generated differs due to a difference in the number of revolutions of the tool in each processing step, and there has been a problem that a step occurs in the axial direction (Z-axis direction) of the workpiece between the processing steps.

As a means for solving this problem, it has been proposed that the machine tool itself does not generate heat by cooling the entire spindle portion of the spindle or the like, but it has not been completely eliminated.

[0006]

As described above, the conventional tool holder has not been provided with a function of actively preventing the transmission of heat from the spindle of the machine tool.

As a result, the above-described problem has occurred.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a tool holder capable of preventing heat generated by a main shaft of a machine tool from being transmitted to a tool holder. It is.

[0009]

Means for Solving the Problems To solve the above-mentioned problems,
In order to achieve the object, a tool holder according to the present invention, in a tool holder mounted on a main spindle of a machine tool, suppresses transmission of heat generated from the main spindle to the tool holder from the main spindle. It is characterized in that means are provided.

The tool holder according to the present invention is characterized in that a groove for heat insulation is provided on the outer peripheral surface of the main body of the tool holder in contact with the tapered hole of the spindle of the machine tool.

Further, in the tool holder according to the present invention, a hole is provided inside the body of the tool holder, a cooling medium is supplied to the hole from a machine tool side, and the cooling medium is supplied to the inside of the body of the tool holder. After passing through the tool holder, it is discharged to the outside from the end face of the tool holder.

Further, in the tool holder according to the present invention, the cooling medium is discharged from an end face of the tool holder toward a tip end of the tool holder via a nozzle.

Further, in the tool holder according to the present invention, a heat insulating material is provided on a mounting surface of the main body side of the tool holder to the main spindle.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described.

First, an outline of an embodiment will be described.

The inventor of the present application paid attention to the following high-speed cutting mechanism.

According to the high-speed cutting, heat generated between the cutting tool and the workpiece is instantaneously taken away by the cutting powder and discharged to the outside, so that the cutting heat is transmitted to the cutting tool and the tool holder. I won't.

Therefore, by providing a structure for blocking the heat transmitted from the spindle to the tool holder, the expansion of the tool holder due to heat is suppressed, and the accuracy of the workpiece in the axial direction (Z-axis direction) is ensured. Processing without steps can be performed.

Further, according to the high-speed cutting, there is an advantage that the cutting resistance can be reduced and the rigidity of the tool holder is not required as much as in the prior art.

In the present embodiment, the transfer of heat from the spindle of the machine tool to the tool holder is suppressed, the extension of the tool holder due to thermal expansion is suppressed, and the machining accuracy is improved.

Further, in order to suppress the transfer of heat from the spindle of the machine tool to the tool holder, a groove is added to the outer periphery of the tool holder body.

Further, a cooling hole is provided inside the tool holder body to prevent heat generation by a refrigerant such as air or water.

In addition, by discharging refrigerant such as air or water discharged from the end face of the tool holder toward the tip of the tool holder, heat generation of the entire tool holder is prevented.

Further, a heat insulating material is arranged between the machine tool and the mounting surface on which the tool holder is mounted so that heat on the machine tool side is not transmitted.

Hereinafter, description will be made with reference to the drawings.

FIG. 1 is an external view of a tool holder mounted on a machine tool according to one embodiment of the present invention.

The tool holder at the tip of the tool holder is omitted here because there are many types.

In FIG. 1, a hollow spindle 3 rotatably held by a headstock 1 of a machine tool has a tapered surface 1 of a tool holder 11 in a taper hole (7/24 taper).
Then, the pull-stat bolt 13 at the rear end of the tool holder is pulled in by the draw bar 5 and attached to the machine tool.

When the main shaft 3 of the machine tool rotates, the main shaft 3 generates heat due to frictional heat or the like.

This heat is applied to the tapered surface 1 of the tool holder 11.
5, the tool is extended to the tool holder body at the tip thereof in the axial direction (Z-axis direction) by thermal expansion, and the workpiece is processed by the tool. The processing accuracy is deteriorated, or a step is formed in each processing step.

For this reason, the present embodiment is provided with a configuration for preventing heat generated in the main shaft 3 of the machine tool from being transmitted to the tool holder.

Specifically, as shown in FIG. 1, a ring-shaped member 31 having heat insulating property is interposed between the main shaft 3 and the tool holder 11 so that heat is hardly transmitted from the main shaft 3 to the tool holder 11. . The ring-shaped member 31 is preferably attached to the attachment surface 19 on the tool holder 11 side.

Also, as shown in FIG.
By providing a groove on the circumference of the tapered surface 15 to reduce the contact area with the tapered hole of the main shaft 3, heat may not be easily transmitted from the main shaft 3 to the tool holder through the tapered hole. The number of grooves provided on the tapered surface 15 is determined in consideration of the rigidity of the tool holder 11.

By providing a groove in the tapered surface 15, the contact area with the tapered hole of the main shaft 3 is reduced, and there is a concern that the holding force of the tool holder 11 may be reduced. This is not a problem because the rigidity of the holder is not required conventionally.

Also, as shown in FIG.
Several cooling holes are provided on the circumference inside the body of the above, from the machine tool side through the internal through hole of the pull-stat bolt 13,
Tool holder 1 by passing a coolant such as air or water
The heat of 1 may be positively taken away.

The coolant such as air or water discharged from the end face 17 of the tool holder 11
The direction may be determined with respect to the tip portion of the light emitting device.

More specifically, the nozzle 21 shown in FIGS.
The fitting portion 23 of the tool holder 11 is fitted into a hole provided in the end face 17 of the tool holder 11, and the nozzle tip 25 is installed so as to face the tip of the tool holder 11.

[0038]

As described above, according to the present invention,
The heat generated by the main shaft of the machine tool is less likely to be transmitted to the holder main body side through the tapered hole of the main shaft, so that elongation due to thermal expansion of the tool holder can be suppressed.

By doing so, the position of the cutting edge of the cutting tool provided at the tip of the tool holder is always in a stable state, so that the processing accuracy in the axial direction (Z-axis direction) of the workpiece can be improved, and the level difference in the workpiece can be improved. Can be prevented from being formed.

[Brief description of the drawings]

FIG. 1 is an external view of a tool holder attached to a machine tool according to an embodiment of the present invention.

FIG. 2 is a structural diagram of a tapered outer peripheral surface of a tool holder.

FIG. 3 is a cross-sectional view of the tool holder.

FIG. 4 is a perspective view of a nozzle of a refrigerant discharge section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle head 3 Spindle 5 Draw bar 11 Tool holder 13 Pull stat bolt 15 Tool holder main body outer peripheral surface 17 Tool holder end surface 19 Tool holder mounting surface 21 Nozzle main body 23 Nozzle mounting part 25 Nozzle tip part 31 Ring-shaped member

Claims (5)

[Claims] 1. A tool holder mounted on a spindle of a machine tool, comprising: means for suppressing heat generated from the spindle from being transmitted from the spindle to the tool holder. holder. 2. The tool holder according to claim 1, wherein a groove for heat insulation is provided on an outer peripheral surface of the main body of the tool holder, which is in contact with the tapered hole of the spindle of the machine tool. 3. A hole is provided inside the body of the tool holder, a cooling medium is supplied from the machine tool side to the hole, and after passing the cooling medium through the inside of the body of the tool holder,
The tool holder according to claim 1, wherein the tool holder is discharged from an end face of the tool holder to the outside. 4. The tool holder according to claim 3, wherein the cooling medium is discharged from an end face of the tool holder through a nozzle toward a tip end of the tool holder. 5. The tool holder according to claim 1, wherein a heat insulating material is provided on a surface of the body of the tool holder to be attached to the spindle.