JP2003117758A - Tool, tool holder and machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a miniaturized tool detachably mounted to a spindle of a machine tool, drivable without supplying electric power from the outside and capable of obtaining higher rotating speed than the spindle of the machine tool. SOLUTION: This tool has a cutting tool 100 for machining a workpiece; a motor 80 for driving the cutting tool 100; and a generator 70 receiving rotational force transmitted from the spindle 46 of the machine tool and generating electric power for driving the motor 80. Sealed bearings with a lubricant sealed inside are used as bearings 72, 92 for rotatably supporting a transmission member 62 for transmitting the rotational force of the spindle 46 to the generator, and drive shafts 81, 91 for transmitting the rotational force generated by the motor 80, to the cutting tool 100.

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 holding a tool mounted on a spindle of a machine tool, a work tool such as an end mill, and a machine tool having the tool or the tool holder attached to and detached from the spindle. .

[0002]

2. Description of the Related Art For example, in a machine tool having a spindle such as a machining center, the maximum number of revolutions (per unit time) of the spindle is determined by the structure of the main bearing that holds the spindle rotatably and the lubrication method. When it is desired to rotate the tool at a rotational speed increased from the maximum rotational speed, for example, a speed increasing device is used. As a speed increasing device, for example, a device that holds a tool and is attachable to and detachable from a main shaft, and increases the rotational force of the main shaft by a gear mechanism such as a planetary gear mechanism to increase the rotational speed of the tool is known. ing. For example, in a machining center, if you want to temporarily increase the rotational speed of the tool above the maximum rotational speed of the main spindle, attach the speed increasing device as described above to the main spindle in the same way as a normal tool. Is rotating at a high speed.

[0003]

By the way, when the tool is sped up more than the rotational speed of the spindle by the speed-up device using the gear mechanism as described above, if the tool is rotated at an ultrahigh speed of tens of thousands to hundreds of thousands of revolutions. However, the heat generation of the speed increasing device increases, which may affect the processing accuracy due to the thermal expansion of the tool. In addition, at ultra-high speed rotations of tens of thousands to hundreds of thousands of rotations, noise from the speed increasing device also increases. Further, since the speed increasing device has a highly reliable structure that can withstand rotations of, for example, tens of thousands to hundreds of thousands of revolutions, there is a disadvantage that the manufacturing cost is relatively high. Also, in the case of a speed increasing device using a gear mechanism, it is necessary to lubricate the gears and bearings, and since the lubricating oil supply path and discharge path are provided inside the speed increasing device, the size of the device is increased and automatic change by the automatic tool changer is performed. There was a disadvantage that it was difficult. As another speed increasing method, there is a case where a high frequency motor is used as a motor for driving the tool, and a driving current is supplied from a specially prepared control device to the high frequency motor to rotate the tool at a high speed. is there. However,
In this method, since there is a cable that supplies electric power from the outside, it is difficult to perform automatic tool exchange like a normal tool, and there is a disadvantage that the equipment cost is relatively high.

The present invention has been made in view of the above problems, and an object thereof is to be detachably mounted on a spindle of a machine tool like an ordinary tool without supplying electric power from the outside. It is possible to obtain a higher rotation speed than the machine tool spindle, it can be driven without connecting to an external power source, etc.
It is to provide a tool holder and a machine tool provided with these.

[0005]

A tool of the present invention is a tool which is detachably mounted on a spindle of a machine tool, and which includes a processing tool for processing a work, and an electric motor for driving the processing tool.
A rotation force is transmitted from the main shaft of the machine tool, and a generator that generates electric power for driving the electric motor is provided. A transmission member that transmits the rotation force of the main shaft to the generator and a rotation force generated by the electric motor. A hermetically sealed bearing, in which a lubricant is hermetically sealed, is used for each bearing that rotatably supports a drive shaft that transmits the above to the processing tool.

Further, the tool of the present invention is detachably mounted on the main shaft, and has a mounting part as the transmission member for transmitting the rotational force of the main shaft to the generator, the mounting part, and a drive shaft of the electric motor. Is rotatably held via the bearing and is engaged with a non-rotating portion of the machine tool.

Preferably, the generator is an AC generator that supplies a voltage having a frequency according to the rotation speed of the main shaft to an electric motor, and the electric motor is an induction motor rotating at a rotation speed according to the frequency. Is.

A tool holder according to the present invention is a tool holder capable of holding a processing tool for processing a work and detachably mounted on a main shaft of a machine tool body. The tool holder rotatably holds the processing tool. Part, an electric motor for rotating the tool holding part, and a rotational force transmitted from the spindle of the machine tool,
A generator for generating electric power for driving the electric motor, and a transmission member for transmitting the rotational force of the main shaft to the generator, and a drive shaft for transmitting the rotational force generated by the electric motor to the tool holder. A sealed bearing in which a lubricant is sealed is used for each bearing to be supported.

A machine tool of the present invention is a machine tool main body having a main spindle, a drive means for driving the main spindle, and at least one control shaft for changing the relative position of the main spindle and the workpiece, and a workpiece. A processing tool, an electric motor for driving the processing tool, and a generator for transmitting a rotational force from the main shaft to generate electric power for driving the electric motor, the tool being attached to and detached from the main shaft, the driving means, and A machine tool comprising: a control device that drives and controls the control shaft according to a machining program, wherein in the tool, a transmission member that transmits the rotational force of the main shaft to the generator and a rotational force generated by the electric motor are It is characterized in that a sealed bearing in which a lubricant is sealed is used for each bearing that rotatably supports the drive shaft that is transmitted to the processing tool.

In the present invention, the tool that is attached to and detached from the spindle is provided with a generator and an electric motor, and the rotational force of the spindle is used to generate electric power. The generated electric power drives the electric motor to rotate the processing tool. As a result, the tool can be driven without being connected to an external power source or the like, and automatic tool change can be performed. As described above, the tool of the present invention is completely independent of the spindle and the external equipment, and therefore, the lubrication of the bearing used in the tool of the present invention is performed by, for example, supplying the lubricant from the spindle or the outside. If this is done, a lubricant supply path and discharge path are required, and the advantage of completely separating the tool from the spindle and external equipment is lost, and the tool becomes larger. Therefore,
In the present invention, by using the sealed bearing for the rotating portion of the tool, which does not require replenishment of the lubricant, the tool can be completely independent of the spindle and external equipment, and can be downsized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a machining center as an example of a machine tool to which the present invention is applied. The machining center is a so-called numerically controlled machine tool capable of complex machining. The machining center 1
Machine tool main body 2 and numerical control device (NC device) 250
And a programmable controller (PLC) 150. In FIG. 1, the machine tool main body 2 includes a cross rail 37 movably supported at both ends by each axis of a gate-shaped column 38.
7 through a saddle 44 movably supported on the ram 4
5 is provided so as to be movable in the vertical direction (Z-axis direction).

On the saddle 44, a screw portion (not shown) is formed in the horizontal direction through the cross rail 37, and a feed shaft 41 having a screw portion formed on the outer periphery is screwed into the screw portion. A servo motor 19 is connected to one end of the feed shaft 41, and the feed shaft 41 is rotationally driven by the servo motor 19. By rotating the feed shaft 41, the saddle 44 can move in the Y-axis direction.
5 is moved and positioned in the Y-axis direction.

Further, the saddle 44 is formed with a screw portion (not shown) in the vertical direction, and the feed shaft 42 having the screw portion formed on the outer periphery is screwed into the screw portion. Feed shaft 42
A servo motor 20 is connected to the end of the. The feed shaft 42 is rotatably driven by the servo motor 20, and the Z of the ram 45 movably provided on the saddle 44 is thereby driven.
Axial movement and positioning is performed.

A spindle motor 31 is built in the ram 45, and the spindle motor 31 rotationally drives a spindle 46 rotatably held by the ram 45. A tool T including a processing tool such as an end mill and a tool holder that holds the processing tool is attached to the tip of the spindle 46, and the tool T is driven by the rotation of the spindle 46. Below the ram 45, a table 35 to which a work to be processed is fixed is provided so as to be movable in the X-axis direction. The table 35 is formed with a screw portion (not shown), and a feed shaft (not shown) provided along the X-axis direction is screwed into the screw portion, and the servo motor 18 is connected to the feed shaft (not shown). There is. Table 3
5 is moved and positioned in the X-axis direction by the rotation drive of the servo motor 18.

Further, the two gate-shaped columns 38 are formed with screw portions (not shown), respectively. The feed shaft 32a screwed to the screw portions is rotationally driven by the cross rail lifting servomotor 32 to cross rail. 37 moves up and down. An automatic tool changer (ATC) 39 automatically changes various tools T with respect to the spindle 46. The automatic tool changer 39 stores, for example, a tool T in which various processing tools such as end mills and drills are held by tool holders in a magazine (not shown), and the tool T mounted on the spindle 46.
Is stored in the magazine by a tool exchanging arm (not shown), and the required tool T is mounted on the spindle 46 by the tool exchanging arm.

The NC device 250 is the servo motor 1 described above.
The drive control of the servomotors 32 for lifting the rails 8, 19 and 20 and the cross rail is performed. Specifically, the NC device 250 uses the servomotors 18, 19, 20 and 3 in accordance with a work machining procedure defined in advance by a machining program.
Position and speed control between the tool T and the workpiece by 2 is performed. Further, the NC device 250 controls the rotation speed of the spindle 46 by decoding the rotation speed (rotation speed per unit time) of the spindle motor 31 defined by the S code, for example, in the machining program. Furthermore, the NC device 25
0 is the NC program, for example, by deciphering the operation of exchanging the tool T specified by the M code,
Automatic exchange of various tools T is executed.

The PLC 150 is connected to the NC device 250 and the operation panel 200. This PLC150
Performs various sequence controls such as starting and stopping the machining center 1 and outputting signals for turning on and off the display unit of the operation panel 200 according to a predetermined sequence program. In addition, PLC150
Is connected to a spindle motor driver 157 that controls driving of the spindle motor 31. The PLC 150 outputs control commands for starting, stopping, and speed control of the spindle motor 31 to the spindle motor driver 157. In addition, PLC
150 performs various sequence controls.

FIG. 2 is a sectional view showing the structure of an embodiment of the tool of the present invention. In FIG. 2, the tool 60 includes a cutting tool 100 and a tool holder 61 that holds the cutting tool 100. The cutting tool 100 is an embodiment of the processing tool of the present invention. Further, the tool 60 according to the present embodiment
Is an automatic tool changer 3 similar to the normal tool T described above.
It is attached to and detached from the main shaft 46 by 9.

The tool holder 61 includes a mounting portion 62, a case 65 including case members 66, 67 and 68, a generator 70, an electric motor 80, a tool holding portion 90, and a rotation stopping member 85. .

The mounting portion 62 is a gripping portion 62a to be gripped.
A taper shank portion 62b attached to the taper sleeve 46a formed at the tip of the main shaft 46, a pull stud 62c formed at the tip of the taper shank portion 62b, and a case member 66 rotatably. And a shaft portion 62d to be held.

The gripping portion 62a of the mounting portion 62 is mounted on the spindle 46 from the magazine of the automatic tool changing device 39 by the tool changing arm of the automatic tool changing device 39 and from the spindle 46 of the automatic tool changing device 39. It is gripped when it is transported to the magazine.

The taper shank portion 62b of the mounting portion 62 is
By being mounted on the taper sleeve 46a of the main shaft 46, the central axis becomes concentric with the central axis of the main shaft 46.

When the mounting portion 62 is mounted on the taper sleeve 46a of the main shaft 46, the pull stud 62c of the mounting portion 62 is clamped by a collet of a clamp mechanism (not shown) built in the main shaft 46. The clamp mechanism built in the main shaft 46 is a well-known technique, and thus its details are omitted.

The shaft portion 62d of the mounting portion 62 has a case member 6
It is rotatably held on the inner periphery of 6 via a plurality of bearings 72. As the bearing 72, a sealed angular contact ball bearing is used as described later.

A holding member 73 is provided on the inner circumference of the case member 67.
The generator 70 and the electric motor 80 are held via. In the generator 70, the input shaft 71 has a shaft portion 62 of the mounting portion 62.
d is concentrically connected to the generator 70.
The rotational force of 6 is transmitted via the mounting portion 62. Generator 7
For example, a three-phase synchronous generator is used for 0.

Electric power generated by the generator 70 is supplied to the electric motor 80 by a conductive cable (not shown). The electric motor 80 is driven by the electric power supplied from the generator 70. As the electric motor 80, for example, a three-phase induction motor can be used.

The tool holding portion 90 includes a rotary shaft 91, a coupling 93 connecting the rotary shaft 91 and the rotary shaft 81 of the electric motor 80, and a tool mounting member 95 fixed to the tip of the rotary shaft 91. Have. The rotary shaft 91 and the rotary shaft 81 are one embodiment of the drive shaft of the present invention. Electric motor 80
The rotating shaft 81 is rotatably held by a bearing (not shown). The bearing (not shown) that supports the rotating shaft 81 of the electric motor 80 is also one of the bearings of the present invention. Also,
A sealed angular contact ball bearing is used for this bearing as described later.

The rotating shaft 91 is rotatably held on the inner circumference of the case member 68 via a plurality of bearings 92. As the bearing 92, a sealed angular contact ball bearing is used as described later. The tip end side of the rotating shaft 91 is retained by the case member 68 by a retaining member 94.

The cutting tool 100 is held by the tool mounting portion 95, and this cutting tool 100 processes a work. The tool mounting portion 95 is an embodiment of the tool holding portion of the present invention. The blade 100 is specifically various blades such as a drill and an end mill. Also, as other processing tools, polishing,
A grindstone etc. are mentioned.

The case members 66, 67 and 68 are connected by fastening means such as bolts, and these case members 66, 67 and 68 form a case 65. A detent member 85 is provided on the outer periphery of the case member 66. The rotation stopping member 85 is mounted on the mounting portion 6.
By attaching 2 to the taper sleeve 46a of the spindle 46, the tip 85a is inserted into the fitting hole 47a formed in the non-rotating portion 47 such as the ram 45 on the spindle 46 side. Accordingly, the rotation of the case member 66, that is, the case 65 is restricted even if the main shaft 46 rotates.

The bearing 72 of the shaft portion 62d and the rotating shaft 9 described above.
Sealed angular contact ball bearings are used for the bearing 92 of No. 1 and the bearing of the rotary shaft 81 of the electric motor 80. The above-mentioned sealed angular contact ball bearing is a special product, but the sealed ball bearing is generally called a cap bearing in JIS or ISO, and shield type, non-contact seal type, and contact seal type are known. There is. The sealed angular contact ball bearing 300 shown in FIG. 3 is of a contact seal type. In FIG. 3, a plurality of balls 301 as rolling elements are arranged by a retainer 340 so as not to contact each other,
It is arranged between the raceway groove 330a of the inner ring 330 and the raceway groove 330a of the outer ring 320. Inner ring 330 and outer ring 32
The ring-shaped seal members 310 and 311 are provided on both side surfaces of 0. Grease G is enclosed in the space sealed by the seal members 310 and 311.

As the grease G, it is preferable to use, for example, one having a frictional force as small as possible, and the grease G is evenly distributed in the bearing for a long time even at a high speed rotation so that the loss of the grease G is small. Specific examples thereof include Alkanol L75 manufactured by FAG.

Next, an example of the operation of the tool 60 according to this embodiment will be described. First, by the automatic tool changer 39, the tool 6 holding the cutting tool 100 in the tool mounting portion 95.
0 is mounted on the spindle 46 of the machine tool body 2. Tool 60
The front end portion 85a of the anti-rotation member 85 is fitted and inserted into the fitting hole 47a of the non-rotating portion 47, and the rotation of the case 65 is restricted.

From this state, when the spindle 46 is rotated at the number of revolutions N ₀ , the mounting portion 62 of the tool 60 is rotated and the spindle 46 is rotated.
Is transmitted to the generator 70. As a result, the generator 70 generates three-phase AC power when using a three-phase synchronous generator, for example.

The frequency f of the three-phase AC power generated by the three-phase synchronous generator is the spindle 4 when the number of poles of the three-phase synchronous generator is P _1.
When the rotation speed of 6 is N ₀ [min ⁻¹ ], it is represented by the following equation (1).

[0036]

[Number 1] _{f = P 1 × N 0/} 120 [Hz] ... (1)

Therefore, when the main shaft 46 is rotated at the number of revolutions N ₀ , the three-phase AC power having the frequency f represented by the equation (1) is supplied to the electric motor 80.

If a three-phase induction motor is used as the electric motor 80, and the number of poles of this three-phase induction motor is P ₂ , the three-phase induction motor is 2 / P _{2 in} one cycle of three-phase AC.
Since it rotates, the synchronous speed N ₁ of the three-phase induction motor when there is no slippage is expressed by the following equation (2).

[0039]

## EQU2 ## N ₁ = 120 × f / P ₂ [min ^-1 ] ... (2)

[0040] Thus, the rotational speed N ₁ of the tool 60 with respect to the rotational speed N ₀ of the spindle 46 is represented by the following formula (3).

[0041]

[Formula 3] N ₁ = N ₀ × P ₁ / P ₂ [min ⁻¹ ] (3)

As can be seen from the equation (3), the rotation of the spindle 46 is
Number of turns N₀ Is the rotation speed N represented by the above formula (3).₁ Shift to
To be done. As shown in equation (3), the number of poles of the three-phase synchronous generator
P₁ And the number of poles of the three-phase induction motor P ₂ Set the ratio to
Therefore, the rotation speed N of the spindle 46₀ Of tool 60 against
Number of revolutions N₁ It can be seen that the gear ratio of can be set arbitrarily.
That is, the rotation speed N of the spindle 46₀ If you want to speed up
Is the pole ratio P₁ / P₂ When you want to slow down by increasing
The pole ratio P₁ / P₂ To be less than 1,
Number of poles of three-phase synchronous generator P₁ And the number of poles of the three-phase induction motor
P₂ Should be selected in advance.

For example, assuming that the maximum rotation speed Nmax of the spindle 46 is 3000 min ^-1 , the rotation speed of the spindle 46 is sufficient within the above-described maximum rotation speed Nmax in the machining of a work using a normal tool. In many cases. On the other hand, the spindle 4
When the machining center 1 having a maximum rotational speed Nmax of 6 is 3000 min ⁻¹ is used and, for example, when an aluminum alloy material is used for the work and it is desired to perform high-speed machining, the tool 60 is used.
There is a case where it is desired to increase the rotation speed of 3 to 30,000 min ⁻¹ . For such a case, the tools 60 are stored in advance in the magazine of the automatic tool changer 39 of the machining center 1. The tool 60 has a built-in three-phase synchronous generator and three-phase induction motor with the pole number ratio P ₁ / P ₂ of 10 so that the speed increasing ratio is 10.

By the automatic tool changer 39, the spindle 46 is
Then, the tool 60 is automatically mounted in the same manner as a normal tool. Spindle 4
6 drives the spindle motor 31 to rotate, but the tool 60
The rotation speed of the cutting tool 100 held by is controlled by the rotation speed of the spindle 46. That is, in the NC program downloaded to the NC device 250, the cutting speed of the tool 60 is specified by specifying the rotation speed of the spindle 46 by the S code.
A rotation speed of 0 is specified. That is, the NC device 250
By controlling the rotation speed of the spindle 46, the tool 60
The number of rotations of the cutting tool 100 is controlled. For example, tool 60
When it is desired to rotate the cutting tool 100 at 30,000 min ⁻¹ , the rotation speed of the spindle 46 is designated at 3000 min ⁻¹ by the S code in the NC program.

When the main shaft 46 is rotated at 3000 min ^-1 , the generator 70 generates a three-phase alternating current having a frequency corresponding to the rotation speed of the main shaft 46 and the number of poles P ₁ . The electric motor 80 is driven by the three-phase alternating current supplied from the generator 70, and the cutting tool 100 of the tool 60 rotates at a rotation speed of approximately 30,000 min ⁻¹ .

In the state where the cutting tool 100 is accelerated as described above, the work fixed to the table 35 and the cutting tool 100 (spindle 46) are moved relative to each other in accordance with the processing program, thereby cutting the work. .

As a result, for example, when the machining center 1 in which the maximum rotation speed of the spindle 46 is limited is used, the cutting tool 100 is rotated at a rotation speed exceeding the maximum rotation speed of the spindle 46.
By rotating the, it becomes possible to process the work at high speed.

As described above, according to this embodiment, the generator 70 and the electric motor 80 are built in the tool holder 61 that is unitized like a normal tool, and the electric motor 80 is generated by the electric power generated by the generator 70. By driving, the rotation speed of the tool 60 with respect to the main spindle 46 is increased, so even if the main spindle 46 is rotated at a high speed, heat generation does not increase unlike the gear device, thermal expansion of the tool 60 is suppressed, and machining accuracy is improved. The decrease is suppressed.

Further, according to this embodiment, the electric motor 80
Since the inertia of the main shaft 46 can be made smaller than the inertia of the main shaft 46, the responsiveness of the cutting tool 100 can be improved as compared with the case where the main shaft 46 is directly rotated at a high speed.

Further, according to the present embodiment, the tool 60 for increasing the rotation speed of the spindle 46 can be attached to and detached from the spindle 46 and can be replaced by the automatic tool changing device 39 in the same manner as a normal tool. Therefore, it is possible to immediately respond to the demand for high-speed processing while performing processing within the normal rotation speed range. Further, according to the present embodiment, since the cutting tool 100 is driven by the electric power generated by the rotation of the main shaft 46, it is not necessary to supply a driving current from the outside, and as a result, wiring for supplying power is not required.

Furthermore, according to the present embodiment, by using the sealed angular contact ball bearing as the bearing used in the tool 60, it is not necessary to supply the lubricant from the outside of the tool 60,
It is not necessary to provide a lubricant supply passage and a discharge passage in the tool 60. Therefore, the tool 60 can be downsized, and as a result, the tool 60 is suitable for automatic exchange by the automatic tool changer 39.

[0052]

According to the present invention, it is possible to obtain a tool, a tool holder, and a machine tool including these tools, which can obtain a higher rotational speed than the spindle of a machine tool without supplying electric power from the outside. Further, according to the present invention, like a normal tool, it is detachably mounted on the spindle of a machine tool, can be driven without being connected to an external power source, etc., and has been miniaturized to enable automatic tool change. A tool, a tool holder, and a machine tool including these are obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a machining center as an example of a machine tool to which the present invention is applied.

FIG. 2 is a cross-sectional view showing a configuration of an embodiment of a tool of the present invention.

FIG. 3 is a sectional view of an example of a sealed angular contact ball bearing.

[Explanation of symbols]

1 ... Machining center 2 ... Machine tool body 31 ... Spindle motor 39 ... Automatic tool changer 46 ... Spindle 60 ... Tool 62 ... Mounting part 65 ... Case 66, 67, 68 ... Case member 70 ... Generator 80 ... Electric motor 90 ... Tool holder 95 ... Tool mounting section 100 ... Cutting tool 250 ... NC device 300 ... Sealed angular contact ball bearing 310, 311 ... Seal member

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takazumi Watanabe             2068-3 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd.             In the company (72) Inventor Yoshiaki Kai             2068-3 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd.             In the company F-term (reference) 3C016 FA03

Claims (8)

[Claims] 1. A tool which is detachably mounted on a spindle of a machine tool, wherein a machining tool for machining a work, an electric motor for driving the machining tool, and a rotational force transmitted from the spindle of the machine tool. And a generator for generating electric power for driving the electric motor, wherein a transmission member for transmitting the rotational force of the main shaft to the generator and a drive shaft for transmitting the rotational force of the electric motor to the processing tool are rotatable. A tool characterized in that a sealed bearing in which a lubricant is sealed is used for each bearing supported by the tool. 2. A mounting portion which is detachably mounted on the main shaft and which serves as the transmission member for transmitting the rotational force of the main shaft to the generator, the mounting portion and the drive shaft of the electric motor via the bearing. Rotatably held, engaged with the non-rotating part of the machine tool,
The tool according to claim 1, further comprising a case whose rotation is restricted. 3. The generator is an AC generator that supplies a voltage having a frequency corresponding to the rotation speed of the main shaft to an electric motor, and the electric motor is an induction motor rotating at a rotation speed corresponding to the frequency. The tool according to claim 1 or 2. 4. A tool holder capable of holding a processing tool for processing a workpiece and detachably mounted on a spindle of a machine tool main body, the tool holding portion rotatably holding the processing tool, and the tool. A transmission that transmits a rotational force of the main shaft to the generator, and an electric motor that rotates the holding unit, and a generator that generates rotational power from the main shaft of the machine tool to drive the electric motor. A tool holder characterized in that a sealed bearing in which a lubricant is sealed is used for each bearing that supports a drive shaft that transmits a rotational force generated by a member and the electric motor to the tool holding portion. 5. A mounting portion that is detachably mounted on the main shaft and that transmits the rotational force of the main shaft to the generator, the mounting portion, and the drive shaft of the electric motor via the bearing. Rotatably held, engaged with the non-rotating part of the machine tool,
The tool holder according to claim 4, further comprising a case whose rotation is restricted. 6. The generator is an AC generator that supplies a voltage having a frequency according to the rotation speed of the main shaft to an electric motor, and the electric motor is an induction motor rotating at a rotation speed according to the frequency. The tool holder according to claim 4 or 5. 7. A main shaft, and drive means for driving the main shaft,
A machine tool main body including at least one control axis that changes the relative position between the spindle and the workpiece, a processing tool that processes the workpiece, an electric motor that drives the processing tool, and a rotational force transmitted from the spindle, A machine tool comprising: a generator that generates electric power for driving the electric motor; and a tool that is attached to and detached from the spindle, and a control device that drives and controls the drive means and the control shaft according to a machining program, In the tool, a lubricant is sealed in each bearing that rotatably supports a transmission member that transmits the rotational force of the main shaft to the generator and a drive shaft that transmits the rotational force generated by the electric motor to the processing tool. A machine tool characterized in that a sealed bearing is used. 8. The machine tool according to claim 7, further comprising an automatic tool changer for attaching and detaching the tool to and from the spindle.