JP2002137133A - Imbalance amount correction device and tool holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imbalance amount correction device and a tool holder capable of simply and accurately determining arrangement positions of a plurality of weight bodies and having excellent practicality in a configuration for correcting an imbalance amount using the weight bodies. SOLUTION: This imbalance amount correction device has a ringlike turning body 7 provided in the tool holder 5 having a tool holding part 11 in which a tool 3 is held at a tip, fitted in the tool holder 5 holding the tool 3 by the tool holding part 11, and turnable in the peripheral direction for the tool holder 5 and at least two weight bodies 8 capable of moving in the peripheral direction for the turning body 7. The turning body 7 is provided with a direction indication part 9 for indicating a correction direction of an imbalance amount and a correction amount graduation 10 determined and graduated in advance so as to correct an imbalance amount by a predetermined amount to make an imbalance amount of the tool holder 5 in which the tool 3 is provided proper by determining the correction direction due to the turn of the turning body 7 and positioning the weight bodies 8 at correction amount graduation 10 positions for correcting by a predetermined amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for correcting an unbalanced amount of a tool holder with a cutting tool to a proper value, that is, zero, with a cutting tool held between the tool holders. It is about the body.

[0002]

2. Description of the Related Art A collet fitting portion is provided at the tip, and a cutting tool such as a drill or an end mill is sandwiched between the collets fitted into the collet fitting portion. In addition, a tool holder (tool holder) provided with a shank portion fitted to the main shaft at the base end,
Japanese Patent Application Laid-Open No. Hei 8-118119, etc.
It is known.

By the way, in order to perform high-speed and high-precision cutting such as small-diameter hole drilling on a printed circuit board used for a personal computer or a mobile phone, or small-diameter hole drilling on an optical fiber cable connector, a collet is required. It is important that the unbalance amount in the state where the cutting tool is held is zero, that is, the center of gravity and the rotation axis center in the state where the cutting tool is held in the collet match as much as possible. Because, when there is an unbalanced amount, that is, when the center of gravity is displaced from the rotation axis, the displacement of the center of gravity acts as a centrifugal force on the whole, and the tip of the cutting tool during machining is This is because they vibrate.

[0004] The amount of unbalance (also called the amount of unbalance) is based on how much distance and how much mass,
It is whether the center of gravity is shifted.

[0005] The vibration phenomenon of the cutting tool tip caused by the presence of the unbalance amount is remarkable particularly in a machine tool which performs cutting at a high speed of 30,000 revolutions / minute or more. Is shortened.

Therefore, conventionally, various means have been taken to correct the amount of unbalance to zero.

Therefore, as a method of correcting the unbalance amount which has been used recently, there is an unbalance amount correction method using two weights.

This method will be described with reference to FIG. 1. For example, when a cutting tool is sandwiched between collets, the rotation axis A
The direction in which the amount of unbalance occurs and the amount of unbalance are measured (a measuring instrument for measuring the direction in which the amount of unbalance occurs and the amount of unbalance is commercially available), and the unbalance is measured. The direction in which the amount occurs and the amount of imbalance are represented by a vector B.
Is determined, and the positions E and F of the weights that express the vector C at the peripheral edge D of the tool holder are determined. It is to arrange a weight body. Therefore, this method has the advantages that the direction and amount of correction of the imbalance can be varied depending on the position of the weight, and that the tool holder can be used permanently.

However, in the above-described method of correcting the unbalance amount using the two weights, as described above, the position E of the weight that expresses the vector C for canceling the unbalance amount is used.
And F are cumbersome. This is because the positions E and F change logarithmically with the increase / decrease of the correction amount, so that a tool for drawing a vector line or a calculation device capable of logarithmic calculation as shown in FIG. 1 is required.

[0010] Therefore, there is a demand in the market for a method of correcting an unbalance amount that can easily determine the position of the weight body.

SUMMARY OF THE INVENTION The present invention achieves the above-mentioned demands, and has a practically excellent unbalance amount correcting apparatus and tool which can easily and accurately determine the position of a weight for correcting the unbalance amount. A holder is provided.

[0012]

The gist of the present invention will be described with reference to the accompanying drawings.

A tool holder 5 having a tool holding portion 11 at the tip thereof for holding the tool 3 is attached to the tool holder 5 in a state where the tool 3 is held by the tool holding portion 11. A ring-shaped rotating body that is rotatable in the circumferential direction with respect to the tool holder, and at least two weight bodies that are movable in the circumferential direction with respect to the rotating body; A direction indicator 9 for indicating the direction of correction of the unbalance amount, and a correction amount scale 10 previously determined and graduated so that the unbalance amount can be corrected by a predetermined amount. The correction direction is determined by the following formula, and the weight 8 is positioned at the correction amount scale 10 at a predetermined amount so that the unbalance amount of the tool holder 5 provided with the tool 3 is adjusted appropriately. The imbalance correction device. .

In the apparatus for correcting an unbalance amount according to the first aspect of the present invention, a ring-shaped base 6 fitted and fixed to the tool holder 5 is provided, and the base 6 and the rotating body 7 are fitted. The rotating body 7 is configured so as to be rotatable with respect to the base 6 and relates to an unbalance amount correcting device.

Further, in the apparatus for correcting an unbalance amount according to the second aspect, the base 6 is provided with a correction direction scale 12 for positioning the direction indicator 9 at a predetermined position. It relates to a balance correction device.

In the apparatus for correcting an unbalance amount according to any one of claims 2 and 3,
The present invention relates to an unbalance amount correcting device, which is provided with a base fixing mechanism 15 for fixing the substrate to the tool holder 5.

In the apparatus for correcting an unbalance amount according to any one of claims 2 to 4, the rotating body 7 is fixed to the rotating body 7 so that the rotating body 7 cannot be rotated with respect to the base 6. The present invention relates to an unbalance amount correcting device provided with a mechanism 14.

In the apparatus for correcting an unbalance amount according to any one of claims 1 to 5, the correction amount scale 10 includes a minimum value scale and a scale for each correction amount that is an integral multiple of the minimum value. The present invention relates to an unbalance amount correcting device characterized by being configured.

In the apparatus for correcting an unbalance amount according to any one of claims 1 to 6, two weights 8 are used, and correction amount scales 10 are provided symmetrically on the left and right sides of the direction indicator 9. The present invention relates to an unbalance amount correcting device characterized in that:

Further, in the apparatus for correcting an unbalance amount according to any one of claims 1 to 7, the weight body 8 has a weight body immobilization mechanism 13 for making the weight body 8 immovable with respect to the rotating body 7. The present invention relates to a device for correcting an unbalance amount, wherein

In the apparatus for correcting an unbalance amount according to any one of claims 1 to 8, the weight body 8 is disposed in a groove 16 provided in a circumferential direction of the rotating body 7, and the weight body 8 is provided with a groove. 16
And the weight body 8 is configured to slide along the unbalanced amount correcting device.

In the apparatus for correcting an unbalance amount according to any one of claims 1 to 9, a shank portion 4 fitted to a main shaft is provided at a base end as a tool holder 5, while a tip end is provided. Is provided with a collet fitting portion 1, and the collet fitting portion 1 employs a tool holder 5 fitted with a collet 2 for holding a tool 3 such as a drill or an end mill. It relates to an unbalance correction device.

A tool holder having a tool holder 11 for holding the tool 3 at the tip thereof, comprising a ring-shaped rotating body 7 rotatable in the circumferential direction with respect to the tool holder 5, The rotating body 7 has at least two weights 8 that can move in the circumferential direction with respect to the moving body 7. A previously determined and calibrated correction scale 10
The correction direction is determined by the rotation of the rotary body 7, and the weight body 8 is positioned at the correction amount scale 10 at a predetermined amount, so that the tool holder 5 with the tool 3 provided is provided.
The present invention relates to a tool holder provided with an unbalance amount correcting device configured to adjust the unbalance amount of the tool holder.

[0024]

With the tool 3 held in the tool holding portion 11, the tool holder 5 with tool 3 is unbalanced with respect to the rotation axis of the tool holder 5 with tool 3 using a commercially available measuring instrument. Measure the direction of the amount (eg, 120 ° direction) and the amount of unbalance (eg, 2 grams / millimeter), and then
First, the rotating body 7 is rotated in the circumferential direction with respect to the tool holder 5, and the direction indicating unit 9 is positioned in the opposite direction (300 ° direction) of the direction of the unbalance amount, that is, in the correction direction of the unbalance amount. Let it.

Subsequently, the weight 8 is rotated in the circumferential direction with respect to the rotary body 7 to correct the unbalance amount by a predetermined amount. The weight body 8 is located at a scale position (2 grams / mm) corresponding to the balance amount.

Therefore, the direction of correction of the unbalance amount can be easily determined by the rotation of the rotating body 7 in the circumferential direction, and the correction amount scale 10 can correct the unbalance amount by a predetermined amount in advance. Since it is obtained and graduated, it is not necessary to determine the position of the weight body 8 by a troublesome method such as calculation, and it is only necessary to adjust the position of the weight body 8 to the position of the scale corresponding to the measured unbalance amount. The amount of imbalance of the tool holder 5 with the tool 3 is easily and reliably corrected appropriately.

Since the present invention is constructed as described above, it is possible to easily and satisfactorily correct the unbalance amount of the tool holder with the tool, and to excel in practicality in which the tool can be machined with high precision. Technology.

[0028]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate one embodiment of the present invention and will be described below.

In this embodiment, a shank portion 4 fitted to the main shaft is provided at the base end, while a collet fitting portion 1 is provided at the tip end, and the collet fitting portion 1 has a drill or an end mill. The tool holder 5 for holding the tool 3 is attached to the tool holder 5 fitted with the tool 3, and is fitted to the tool holder 5 with the tool 3 holding the tool 3 in the tool holder 11. And a ring-shaped rotating body 7 rotatable in the circumferential direction with respect to the tool holder 5 and at least two weight bodies 8 movable in the circumferential direction with respect to the rotating body 7. In moving body 7,
A direction indicator 9 indicating the direction of correction of the unbalance amount, and a correction amount scale 10 previously obtained and graduated so that the unbalance amount can be corrected by a predetermined amount are provided. Is determined, and the weight 8 is positioned at a predetermined amount position on the correction amount scale 10 so that the unbalance amount of the tool holder 5 provided with the tool 3 is adjusted appropriately. It relates to a balance correction device.

First, the tool holder 5 will be described in detail.

In the tool holding section 11, a collet 2 having a general structure in which a plurality of split grooves 17 are provided in a cylindrical body is fitted to the collet fitting section 1 of the tool holding body 5.

The collet 2 is taperedly fitted to the collet fitting portion 1, and a screw portion 18a is provided on the outer surface on the distal end side of the collet fitting portion 1.
And a screw portion 18b formed on the inner surface of the lock body 19 are screwed. The screw portions 18a and 18b are provided on the entire circumferential surface.

The lock body 19 locks the collet 2 fitted to the collet fitting portion 1. The lock body 19 is screwed onto the collet 2 and the lock body 19 is turned. The collet 2 is tightened by motion.
Is configured to hold the tool 3.

The lock body 19 comprises an inner race 20 and an outer race 21.
The inner ring 20 is connected to the collet 2 and the concave / convex fitting portion 22, and the outer ring 20 is rotatable with the inner ring 21.
(In the first embodiment, balls are used.) Therefore, the rotation of the outer wheel 21 is not transmitted to the inner wheel 20, and the inner wheel 20 follows the movement of the outer wheel 21 with respect to the movement of the outer wheel 20 in the collet axial direction (the left-right direction in FIG. 4). Further, since the inner peripheral surface at the tip of the inner ring 20 is formed on the tapered surface 25 corresponding to the tapered surface 24 at the tip of the collet 2,
A tool clamping force acts on the collet 2 due to the movement of the inner ring 20 in the proximal direction (leftward in FIG. 4) due to the rotation of the outer ring 21. The tapered surfaces 24 and 25 are formed as tapered surfaces that incline downward and inward toward the distal end.

With the above structure, when the outer ring 21 is turned and screwed in, the inner ring 20 does not turn and moves toward the base end of the tool holder 5 following the screwing of the outer ring 21. The collet 2 exerts a tool clamping force due to the taper contact between the tapered surface 25 of the inner ring 20 and the tapered surface 24 of the collet 2 and the taper fitting between the collet 2 and the collet fitting portion 1.

When the outer ring 21 is turned and screwed out,
Conversely, the collet 2 is removed from the collet fitting portion 1 due to the presence of the concave-convex fitting portion 22.

A circumferentially extending ridge 26 is provided at the center of the tool holder 6 in a surrounding state.

Next, the imbalance correction device will be described in detail.

The rotating body 7 is provided in a fitted state on a ring-shaped base 6 fitted and fixed to the tool holder 5.

The base 6 comprises a cylindrical portion 27 and a flange portion 28 provided at the base end of the cylindrical portion 27 so as to be surrounded.

The cylindrical portion 27 is provided with a threaded body as a base fixing mechanism 15 for fixing the base 6 to the tool holder 5. In addition, besides the screw body, as the base fixing mechanism 15,
For example, a taper ring or the like may be employed.

The rotating body 7 is fitted in the cylindrical portion 27.

On the outer peripheral surface of the flange portion 28, on the side edge portion of the cylindrical portion 27,
A correction direction scale 12 is provided for determining the correction direction by matching the direction indicator 9 by sliding the rotating body 7.
The correction direction scale 12 is, for example, 5 degrees from 0 ° to 360 °.
It is an angle scale provided for each °.

The base edge of the flange portion 28 is located at the tool holder 6.
It is configured to abut on the protruding ridge 26.

The rotating body 7 has a ring shape having the same width as the cylindrical portion 27, and is provided with a groove 16 extending in the circumferential direction on the outer peripheral surface, and the weight 8 is disposed in the groove 16. is there.

Further, dovetail grooves 29 are provided on the bottom left and right of the concave groove 16.

An introduction portion 30 for introducing the weight 8 into the groove 16 is provided on the side of the groove 16 opposite to the direction indicating portion 9.

The direction indicating section 9 is provided at the edge of the rotating body 7 on the side of the flange section 28. In addition, the direction indicator 9
, An arrow having a tip on the side of the flange portion 28 is employed. Therefore, when the rotating body 7 is fitted on the cylindrical portion 27 of the base body 6, the direction indicating portion 9 and the correction direction scale 12 are adjacent to each other, so that the direction indicating portion 9 can be easily matched with a desired direction. .

A correction amount scale is provided on the left and right of the direction indicating section 9.
10 are provided symmetrically. This correction amount scale 10
For example, from the direction closer to the direction indicator 9, 10, 8, 7, 6,.
..1,0 (for example, the unit is gram-mm; 0 is 18
It will be in the 0 ° facing state. ), A scale of the minimum value of a certain unit and a scale of an integral multiple thereof.
The scale of the minimum value is not 1 but may be, for example, a decimal value of 0.5, a fractional value, a numerical value of 2, or the like.

The rotating body 7 is attached to the base 6
A penetrating screw body is provided as a rotation body rotation disable mechanism 14 that disables rotation with respect to. In addition, the rotating body non-rotatable mechanism 14 is configured to also exert an action of fixing the rotating body 7 to the base 6.

Two weights 8 are used, each of which is
The tool holder 5 is configured to slide in the circumferential direction along 16.

The bottom of the weight body 8 is provided with projecting pieces 31 projecting left and right, respectively, and the projecting pieces 31 are configured to be introduced into the dovetail grooves 29. Therefore, the weight body 8 has a concave groove.
It does not slip out of the groove 16 and slides well along the groove 16.

Further, the weight body 8 is provided with a threaded body as a weight body immobilization mechanism 13 for making the weight body 8 immovable with respect to the rotating body 7. Further, the weight body immobilization mechanism 13 is configured to also exert an action of fixing the weight body 8 to the rotating body 7.

Further, the weight body 8 has a correction amount indicating section for adjusting the weight body 8 to a predetermined scale of the correction amount scale 10.
32 are provided. Also, the correction amount indicating section 32 employs arrows like the direction indicating section 9. Therefore, the correction amount indicating section 32 of the two weights 8 is set to the correction amount scale.
The two weights 8 can accurately correct the unbalance amount indicated by the predetermined scale of the correction amount scale 10 by matching the predetermined scale of 10.

Next, a method of using this embodiment will be described in detail.

First, the base 6 is fitted on the tool holder 5 and fixed by the base fixing mechanism 15. Further, the lock body 19 is screwed onto the collet 2 and the tool 3 is held by the collet 2 by operating the lock body 19.

Subsequently, the rotary body 7 is fixed to the base 6 by the rotary body non-rotatable mechanism 14, and the two weights 8 are weighted to the zero position (180 ° facing position) of the correction amount scale 10. It is fixed by the body immobility mechanism 13.

Subsequently, in this state, the direction of the unbalance amount and the unbalance amount of the tool holder 5 with the tool 3 are measured by a dedicated unbalance amount measuring machine or the like. The direction of the unbalance amount by this measurement is read by the correction direction scale 12. For convenience of description, the direction of the unbalance amount is set to 120.
°, the amount of unbalance is 2 grams / mm.

Subsequently, the fixing of the rotating body 7 to the base 6 is released, and the rotating body 7 is rotated so that the direction indicating section 9 is set to 300 ° (120 ° + 180 °) of the correction direction scale 12. Fix it again. On the other hand, the fixing of the two weights 8 to the rotating body 7 is released, respectively, and the weights 8 are slid along the concave grooves 16 so that the correction amount indicating section 32 is set to 2 gm of the correction amount scale 10. Fit to the millimeter and fix again. Note that the position of the weight body 8 may be between the scales of the correction amount scale 10.

In this state, the imbalance amount has already been optimized, that is, the imbalance amount has been corrected to zero.

Hereinafter, the shank portion 4 is fitted to the main shaft in this state, and the machining operation is appropriately performed by the tool 3.

When the base 6 is fixedly fitted to the tool holder 5, the rotating body 7 is fitted to the base 6 and the concave groove of the rotating body 7 is formed.
If the unbalance amount correcting device is handled in an integrated state in which the weight body 8 is disposed on 16, the handling can be performed well.

Further, for example, an unbalance amount correcting device may be provided on the tool holder 5 connected to the main shaft, and the unbalance amount may be corrected by the same method as in this embodiment.

Since the present embodiment is constructed as described above, the rotating body 7 is rotated to adjust the direction indicating section 9 to the direction of correcting the unbalance amount, and the weight body 8 is moved to adjust the correction amount scale 10.
An extremely simple operation of disposing the weight body 8 on the scale of a predetermined amount represented by the formula (1) makes it possible to reduce the unbalance amount to an appropriate value, that is, to zero, which is excellent in practicality and workability. It becomes a balance correction device.

Since the correction amount scale 10 is previously obtained and graduated so that the unbalance amount can be corrected by a predetermined amount, it is very simple to adjust the determination of the correction amount of the unbalance amount to the scale. Can be done by work.

Further, since the correction direction scale 12 used for positioning the direction indicating section 9 is provided, the operation of adjusting the correction direction of the unbalance amount can be performed by an extremely simple operation.

Since the method of correcting the unbalance amount using the two weights 8 is used, even if the direction of the unbalance amount and the unbalance amount change due to the replacement of the tool 3 or the like, the unbalance amount can be easily changed. Can be corrected in response to changes in Moreover, the unbalance amount can be corrected to zero only by the rotation of the rotating body 7 and the movement of the weight body 8, and it is possible to respond to the change in the unbalance extremely quickly.

The weight 8 is composed of a minimum value of the unbalance amount that can be corrected by moving the weight 8 and a scale for each correction amount that is an integral multiple of the minimum value.
The direction of the unbalance amount and the unbalance amount can be measured in a state where is adjusted to the position of 0.
The amount of imbalance that can be corrected by the movement of the weight 8 can be understood at a glance, and the movement of the weight 8 with a logarithmic change can be captured not by the logarithmic method but by the amount of imbalance. The movement can be performed very easily.

Further, since the rotating body 7 has a ring shape, the rotating operation can be easily performed in the circumferential direction of the tool holder 5.

Further, since the weight 8 slides along the concave groove 16 provided on the rotating body 7, the operation of moving the weight 8 can be easily performed.

The tool holder 5 is of a type in which the collet 2 is widened and narrowed by the rotation of the lock body 19 so that the tool 3 can be clamped, so that the amount of unbalance is small. Precision machining can be performed.

Further, since the lock body 19 has a configuration in which the outer race 21 and the inner race 20 are interposed with the rolling elements 23, the inner race 20 does not rotate when the outer race 21 rotates, and thus acts on the collet 2. The pushing force from the lock body 19 acts on the tool 3 well, so that the amount of imbalance caused by clamping the tool 3 between the collet 2 is small, and in this regard, high-speed and high-precision machining can be performed. become.

In the present embodiment, the case where two weights 8 are used has been described. For example, even when three weights are used, the correction amount when the three weights are used is not changed. If provided as a correction amount scale, the imbalance amount can be similarly corrected. This is the same even when four or more weights are used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method of correcting an imbalance amount using two weights.

FIG. 2 is an explanatory exploded perspective view of the present embodiment.

FIG. 3 is an explanatory perspective view of the present embodiment.

FIG. 4 is an explanatory partial cross-sectional side view of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Collet fitting part 2 Collet 3 Tool 4 Shank part 5 Tool holding body 6 Base 7 Rotating body 8 Weight body 9 Direction indication section 10 Correction amount scale 11 Tool holding section 12 Correction direction scale 13 Weight body fixing mechanism 14 Rotating body fixing mechanism 15 Base fixing mechanism 16 Groove

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuo Seki 2600-1, Chiya Ko, Ojiya, Niigata Prefecture Inside of Kiwa Seiko Co., Ltd. (72) Inventor Yoshiaki Sato 2600-1, Chiya Ko, Ojiya, Niigata Prefecture Yu F term in Kiwa Seiko Co., Ltd. (reference) 3C016 AA02 FA21

Claims (11)

[Claims] 1. A tool holder having a tool holding portion for holding a tool at a tip thereof, wherein the tool holding portion holds a tool in the tool holding portion and is fitted to the tool holding member. A ring-shaped rotating body rotatable in the circumferential direction with respect to the rotating body, and at least two weight bodies movable in the circumferential direction with respect to the rotating body; And a correction amount scale previously determined and graduated so that the unbalance amount can be corrected by a predetermined amount. The correction direction is determined by the rotation of the rotating body, and the weight body is Is arranged at a correction amount scale position of a predetermined amount so that the unbalance amount of the tool holder in a state where the tool is provided is made appropriate. 2. The unbalance correction device according to claim 1, further comprising: a ring-shaped base fitted and fixed to the tool holder, wherein the base and the rotating body are fitted to each other. An unbalance amount correcting device, which is configured to be rotatable with respect to a base. 3. The unbalance amount correcting device according to claim 2, wherein the base is provided with a correction direction scale for positioning the direction indicating portion at a predetermined position. apparatus. 4. The apparatus according to claim 2, wherein the base is provided with a base fixing mechanism for fixing the base to the tool holder. Balance correction device. 5. The unbalance amount correcting device according to claim 2, wherein the rotating body is provided with a rotating body non-rotatable fixing mechanism that makes the rotating body non-rotatable with respect to the base. An imbalance amount correcting device, characterized in that: 6. An unbalance amount correcting apparatus according to claim 1, wherein the correction amount scale includes a minimum value scale and a scale for each correction amount that is an integral multiple of the minimum value. An imbalance amount correction device characterized by being performed. 7. The unbalance amount correcting apparatus according to claim 1, wherein two weight bodies are used,
An imbalance correction device, wherein the correction scale is provided symmetrically on the left and right sides of the direction indicator. 8. The unbalance amount correcting device according to claim 1, wherein the weight body is provided with a weight body immobilization mechanism that makes the weight body immovable with respect to the rotating body. An imbalance correction device. 9. The unbalance amount correcting device according to claim 1, wherein the weight is disposed in a groove provided in a circumferential direction of the rotating body, and the weight is arranged along the groove. An unbalance amount correcting device, wherein the weight body is configured to slide. 10. The device for correcting an unbalance amount according to claim 1, wherein a shank portion fitted to a main shaft is provided at a base end as a tool holder.
A collet fitting part is provided at the tip, and the collet fitting part employs a tool holder fitted with a collet for holding a tool such as a drill or an end mill. apparatus. 11. A tool holding body having a tool holding portion for holding a tool at a tip thereof, comprising: a ring-shaped rotating body rotatable in a circumferential direction with respect to the tool holding body; Having at least two weights movable in the circumferential direction,
The rotating body is provided with a direction indicator that indicates the direction in which the unbalance amount is corrected, and a correction amount scale previously obtained and graduated so that the unbalance amount can be corrected by a predetermined amount. An unbalance amount configured to determine a correction direction and to position the weight at a predetermined correction amount graduation position so that an unbalance amount of the tool holder in a state where a tool is provided is appropriate. A tool holder provided with a correction device.