JP3115815B2 - Tool holder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holder detachably mounted on a main shaft of a machine tool.

[0002]

2. Description of the Related Art An automatic tool changer is provided in a machine tool such as a machining center, and a tool holder on which a tool is mounted can be attached to and detached from a main spindle of the machine tool by the automatic tool changer. Then, the tool holder attached to the main shaft is connected at one point of contact with the tapered hole of the main shaft and the tapered surface of the shank portion of the tool holder, and is pulled inward in the axial direction by a pulling means provided inside the main shaft. As a result, the contact strength between the tool holder and the main shaft (hereinafter, referred to as “coupling rigidity”) is enhanced by strengthening the contact between the tapered hole and the tapered surface.

[0003] The coupling stiffness has a significant effect on machining accuracy. That is, if the coupling rigidity is insufficient, heavy cutting and high-speed rotation cannot be tolerated, and not only the main shaft and the tool holder vibrate, but also the tool may fall down or run out. In order to increase the coupling rigidity, it is conceivable to increase the tensile strength of the pulling means. However, since this is naturally limited, conventionally, the coupling rigidity was increased without increasing the pulling force of the pulling means. There has been proposed a tool holder which can be operated (Japanese Utility Model Application Laid-Open No. 63-53605).
Reference).

This conventional tool holder is provided with a sleeve fitted in a tapered hole of a main shaft of a machine tool, a shank slidably fitted in the sleeve, and provided integrally with the shank. It has a flange portion that can abut on the end face of the main shaft, and an elastic member that urges the sleeve away from the flange portion. On the outer peripheral portion of the sleeve, a slit is formed along the axis thereof so as to penetrate the thickness of the sleeve. This slit portion may be formed only by one piece that passes through the sleeve along the axis of the sleeve, or may be formed such that a plurality of pieces are formed in the sleeve in the circumferential direction so as not to pass through the sleeve. is there.

When the conventional tool holder is fitted into the main shaft of the machine tool by the automatic tool changer, even if the tapered surface of the outer periphery of the sleeve of the tool holder comes into contact with the tapered hole of the main shaft of the machine tool, A predetermined gap is left between the flange end face of the holder and the spindle end face of the machine tool. However, this predetermined gap is closed when the pulling means provided on the spindle draws the tool holder inward in the axial direction next, so that the flange end face and the spindle end face come into contact with each other.
At this time, the sleeve is urged inward by the elastic member into the tapered hole of the main shaft, so that the contact with the tapered hole is further strengthened. In addition, since the sleeve of the tool holder is pressed all around by the tapered hole of the main shaft, the width of the slit portion is reduced, so that the inner diameter of the sleeve is reduced, and the coupling between the sleeve and the shank portion is strengthened. Is done.

As described above, in the conventional tool holder, the tapered surface of the outer peripheral portion of the sleeve and the tapered hole of the main shaft of the machine tool and the flange end surface and the main shaft end surface are in close contact with each other, and the diameter of the sleeve is reduced. As a result, the connection with the shank portion is strengthened, so that a stronger connection rigidity can be obtained even with the same pulling force, as compared with a connection in which only the tapered hole and the tapered surface are connected at one place.

[0007]

In the conventional tool holder, there is a problem that dust enters into a slit provided in the sleeve. In such a case, the diameter of the sleeve is insufficiently reduced at the next use of the tool holder, and the tool holder may not be able to be pulled in by a required amount with respect to the main shaft of the machine tool. In other words, the flange end face of the tool holder may not come into contact with the spindle end face of the machine tool.Therefore, the coupling between the sleeve and the shank is also insufficient, and the tool holder is not attached to the machine tool spindle during heavy cutting or high-speed rotation. May vibrate, or the tool may fall down or run out.

In addition, since the conventional sleeve has a slit, the circumferential direction is discontinuous, rigidity is reduced, and dynamic imbalance during rotation is caused. The present invention has been made in view of the above circumstances, and is intended to prevent the dust from being clogged in the sleeve portion and to reduce the diameter of the sleeve reliably at the next use of the tool holder. Another object of the present invention is to provide a tool holder capable of preventing the vibration of the tool holder at the time of high-speed rotation and the fall of the tool and the runout of the tool.

[0009]

According to the present invention, the following technical measures have been taken in order to achieve the above object. That is, in the present invention, a sleeve that fits into the tapered hole of the main shaft of the machine tool, a shank portion that is slidably fitted in the sleeve, and an end surface of the main shaft that is provided integrally with the shank portion. In a tool holder having an abutting flange portion and an elastic member for urging the sleeve in a direction away from the flange portion, the sleeve has an inner groove formed on an inner peripheral surface thereof along an axis of the sleeve, A plurality of inner grooves of the sleeve are provided equidistantly in the circumferential direction of the sleeve.
A slot is formed in the inner groove along the bottom of the groove and penetrates through the thickness of the sleeve. The slit is filled with an elastic filler, and the sleeve alone moves around the axis. The inner groove is formed so that the target is balanced
Tool holder characterized by doing.

The procedure for attaching the tool holder of the present invention to the main shaft of the machine tool is substantially the same as that of the prior art. The automatic tool changer is used to fit the tool holder into the tapered hole of the main shaft of the machine tool. Is drawn inward in the axial direction. As a result, the end face of the flange portion of the tool holder is brought into contact with the end face of the spindle of the machine tool. At this time, the sleeve of the tool holder is pressed into the tapered hole of the main shaft by the elastic member, so that the contact with the tapered hole is further strengthened.

Further, as the tapered surface of the outer peripheral portion of the sleeve is radially inwardly pressed by the tapered hole of the main shaft, a compressive force is generated in the circumferential direction. In the tool holder of the present invention, in the part thinned by the provision of the inner groove, the amount of compressive deformation in the circumferential direction is larger by the smaller radial cross-sectional area than in the thick part without the inner groove. Become. Accordingly, the circumferential length of the sleeve is shortened accordingly, and the inner diameter of the sleeve is reduced as a whole. As a result, the connection between the sleeve and the shank is also strengthened.

By the way, unlike the sleeve of the conventional tool holder, the inner groove does not open toward the tapered surface of the outer periphery of the sleeve. Therefore, dust and the like do not enter the inner groove. Therefore, it is possible to prevent the diameter of the sleeve from becoming insufficient at the next use of the tool holder. A plurality of inner grooves of the sleeve are provided equidistantly in the circumferential direction of the sleeve, each inner groove is inclined with respect to the axis of the sleeve, and the thickness of the sleeve corresponding to the inner groove is constant along the axis of the sleeve. It is possible to have a structure formed while maintaining the thickness.

[0013] In this case, the sleeve is balanced around the rotation axis, and uneven rotation is less likely to occur, so that the sleeve is suitable for high-speed rotation. A plurality of inner grooves of the sleeve are provided equidistantly in the circumferential direction of the sleeve, and one of the inner grooves is formed with a slit portion penetrating the thickness of the sleeve along the bottom of the groove. the elastic filling material is a packed structure.

With this configuration, the slit has an advantage that the sleeve can be easily reduced in diameter when the tool holder is fitted to the main shaft of the machine tool. It is possible to prevent dust and the like from entering. In addition, the elastic filler packed in the slit portion, when the action of expanding and contracting the opening width of the slit portion is added to the sleeve, freely with this,
Since the sleeve is compressed or returns to the shape before compression, there is no adverse effect on the operation of the sleeve such as reducing the diameter.

By positioning the slit at the bottom of the inner groove, the elastic filler filled in the slit can fill the inner groove. In this case, even if the tool holder is rotated at a high speed, the elastic filler in the slit can be prevented from being displaced, popped out, deformed, or the like due to centrifugal force. It is preferable that the groove width of the other inner groove is formed to be wider than the groove width of the inner groove provided with the slit portion.

With this arrangement, the thickness of the thinned portion corresponding to the slit portion and the thickness of the thinned portion by widening the groove width are balanced in the circumferential direction of the sleeve, so that uneven rotation of the sleeve hardly occurs. It becomes suitable for.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 4, which shows a cross section of one embodiment of the tool holder according to the present invention, the tool holder is provided with a sleeve 3 fitted in a tapered hole 2 of a main shaft 1 of a machine tool, and slidably inserted into the sleeve 3. A fitted shank portion 4, a flange portion 5 provided integrally with the shank portion 4 and abutting on the end face of the main shaft 1, and provided between the flange portion 5 and the sleeve 3. And an elastic member 6 for urging the member in a direction away from the flange portion 5. The elastic member 6 is composed of a combination of a disc spring and a flat washer.

The main shaft 1 of the machine tool is provided with a pulling means 7 for drawing in a tool holder mounted in the tapered hole 2 of the main shaft 1. The main shaft 1 is provided with a coolant supply device (not shown) for supplying coolant to the tapered hole 2 and a compressed air supply device (not shown) for supplying cleaning air.

The sleeve 3 is a cylindrical body having an inner and outer peripheral surface. The outer peripheral portion is formed as a tapered surface, and the inner peripheral portion is formed as a straight surface. 1, 2 and 3, an inner groove 3a is formed along the sleeve axis and inclined at a predetermined angle, as shown in FIGS. A plurality (three in the illustrated example) of the inner grooves 3 a are provided so as to be evenly arranged in the circumferential direction of the sleeve 3. The inner grooves 3a are formed so as to gradually become wider as they approach the larger-diameter end of the sleeve 3. The sleeve 3 alone has a dynamic balance about the axis.

The taper angle provided on the tapered surface of the sleeve 3 is the same as the taper hole 2 of the main shaft 1. When the tool holder is attached to the main spindle 1 of the machine tool, the inclination θ of the axis of the tool holder tends to decrease as the taper angle is reduced, and the coupling rigidity of the tool holder to the main spindle 1 may increase. understood. At this time, the magnitude of the pulling force of the pulling means 7 has almost no effect.

A preferable taper angle is set to be gentler than 7/24 (about 16 °), which is often used, and a good result is easily obtained when the taper angle is set to be smaller than 12 °. In the present embodiment, 1/10 (approximately 6 °) is adopted to obtain high coupling rigidity.
The shank portion 4 is formed at one end of the holder body 8, and the outer peripheral surface of the shank portion 4 can be slidably and closely fitted to the straight surface of the inner peripheral portion of the sleeve 3. Is formed.

The shank portion 4 has a lubricant groove 4a (see FIG. 1) formed so as to spiral around the outer peripheral surface. Therefore, when the sleeve 3 is fitted in the shank portion 4, the lubricant groove 4a is open toward the inner peripheral surface of the sleeve 3, and a lubricant such as grease can be filled therein. . The lubricant in the lubricant groove 4a is
a.

The flange portion 5 is provided so as to be connected to the shank portion 4 and has a diameter larger than the diameter of the shank portion 4. The flange portion 5 may be one in which a ring body 9 separate from the holder body 8 is integrally connected to the holder body 8 by shrink fitting or the like. This flange part 5
A V-shaped engaging groove 10 into which a tool changing arm (not shown) of the automatic tool changing device is fitted is provided on the outer peripheral surface of the automatic tool changing device.

The end surface of the flange portion 5 on the shank portion side is formed as a flat surface that comes into contact with the end surface of the main shaft 1 of the machine tool. A mounting seat 11 for the elastic member 6 is formed on the inner peripheral side of the flat surface of the flange portion 5. The mounting seat 11 is formed by an annular recess formed in the flat surface. The elastic member 6 is formed in a ring shape, is formed of a combination of a disc spring and a flat washer (shim plate), and is housed in a concave portion of the mounting seat 11.

However, as shown in FIG. 5, the elastic member 6 comprises a compressed body 12 made of an elastic material and a non-compressed body 13 made of a hard material.
Are joined without any gap in the axial direction. In this case, one end surface of the elastic member 6 is in contact with the end surface of the sleeve 3, and the other end surface is in contact with the radial side surface of the mounting seat 11 in the flange portion 5. The inner peripheral surface of the elastic member 6 is in close contact with the outer peripheral surface of the shank portion 4, and the outer peripheral surface of the elastic member 6 has a predetermined gap with the inner peripheral surface of the mounting seat 11.

The compression body 12 is formed of an elastic material such as urethane soft resin or rubber, fluorine or other soft resin, or other synthetic rubber. In this embodiment, the thickness is 1 mm. The uncompressed body 13
Is formed of a hard material such as a metal plate such as a steel plate. In the present embodiment, the thickness is 0.2 mm.
And

In this embodiment, the compressed body 12 and the non-compressed body 1
A total of 5 combinations of 3 were joined. Therefore, the overall thickness of the elastic member 6 is 6 mm. A pull stud 14 is screwed to the rear end of the shank 4 of the holder body 8. A tool insertion hole 15 is provided through an axis of the pull stud 14.
In addition, a protrusion 16 having a diameter larger than the outer diameter of the shank 4 is provided on an outer peripheral portion of the pull stud 14,
The protrusion 3 prevents the sleeve 3 from coming off.

Between the protrusion 16 and the sleeve 3,
Preload applying means 17 is interposed. The preload applying means 17 applies a preload to the elastic member 6 to make the assembly distance between the end surface of the sleeve 3 and the flat surface of the flange portion 5 constant. In this embodiment,
As the preload applying means 17, a means comprising a plurality of spacers was used. That is, by adjusting the thickness of the spacer or the number of used spacers, the variation in the thickness of the elastic member 6 is corrected, and the assembly distance between the sleeve end surface and the flat surface of the flange portion 5 is made constant.

In the holder body 8, an end opposite to the shank portion 4 via the flange portion 5 is a tool holding portion 18. The tool holding portion 18 is provided with a collet holding hole 19 that opens on the front end side in a concentric manner. The collet holding hole 19 is formed with a gentle taper surface, and a taper collet 20 is mounted in the holding hole 19.

The taper collet 20 has a tool holding hole 21 provided concentrically at the tip end thereof, and a female screw portion 22 provided concentrically at the rear end side thereof. The tool holding hole 21 has a cutting tool 2 such as an end mill or a drill.
3 is detachably inserted and held. A draw bolt 24 is rotatably held at the axial center of the holder body 8 while being restrained from moving in the axial direction.
4 is screwed into the female screw part 22 of the tapered collet 20. A tool engaging portion 25 is provided in the head of the draw bolt 24. Furthermore, draw bolt 24
The coolant supply hole 26 penetrates the shaft center portion of.

A tool (not shown) such as a hexagon wrench is inserted through the tool insertion hole 15 of the pull stud 14, and the tip of the tool is engaged with the tool engaging portion 25 of the draw bolt 24. By rotating the 24, the taper collet 20 can be moved relative to the collet holding hole 19 in the axial direction. The axial movement of the taper collet 20 causes the tool holding holes 21
Of the tool 23 inserted into the device is released or released.

The tool holder according to the present invention having such a configuration is stored in a magazine (not shown) of an automatic tool changer with the cutting tool 23 mounted. Then, a tool changing arm (not shown) of the automatic tool changing device grips the engaging groove 10 of the tool holder, takes out the tool holder from the magazine, and conveys the tool holder to the main spindle 1 of the machine tool. Fit into 2.

At this time, the tapered hole 2 of the main shaft 1 and the tapered surface of the sleeve 3 of the tool holder are closely fitted. In this fitting state, a predetermined gap is formed between the end surface of the main shaft 1 and the flat surface of the flange portion 5 of the tool holder. This gap is 0.5 mm in this embodiment. The assembly gap between the sleeve 3 and the flange 5 is adjusted in advance by the preload applying means 17 so that the gap is constant.

Next, the pulling means 7 provided inside the main shaft 1 grips the prestud 14 and pulls the holder body 8 inward in the axial direction of the main shaft 1. Due to this retraction, the shank portion 4 and the flange portion 5 attempt to move integrally in the axial direction, and the moving force is transmitted to the sleeve 3 via the elastic member 6. At this time, in the sleeve 3, an axial relative movement occurs between the inner surface of the sleeve 3 and the outer peripheral surface of the shank portion 4 due to a difference in movement resistance generated on the inner and outer peripheral surfaces.
Therefore, the sleeve 3 has a tapered surface on its outer peripheral portion that is the main shaft 1.
Is pressed by the entire tapered hole 2.

As described above, when the tapered surface of the sleeve 3 is pressed radially inward over the entire circumference, a compressive force is generated in the sleeve 3 in the circumferential direction. Therefore, in the part thinned by the provision of the inner groove 3a, the amount of compressive deformation in the circumferential direction is increased by the smaller radial cross-sectional area than in the thick part without the inner groove 3a. As a result, the circumferential length of the sleeve 3 becomes shorter. As a result, the inner diameter of the sleeve 3 is reduced as a whole, and as a result, the coupling between the sleeve 3 and the shank portion 4 is strengthened.

When the sleeve 3 moves in the axial direction, the elastic member 6 is also compressed in the axial direction, and the flat surface of the flange portion 5 comes into contact with the end face of the main shaft (see FIG. 5). At this time, since the sleeve 3 is pressed inward of the tapered hole 2 in the main shaft 1 by the repulsive force due to the compression of the elastic member 6, the action of reducing the inner diameter of the sleeve 3 by this pressing force is further enhanced, and , The tapered surface of the sleeve 3 and the tapered hole 2 of the main shaft 1
Therefore, the connection between the sleeve 3 and the shank portion 4 is further strengthened.

After the pulling-in step is completed, the grip of the tool change arm is released, and the arm returns to the original standby position. In this retraction process, the preload applying means 17 adjusts the retraction amount of the tool holder to a very short value of 0.5 mm (this was as large as 3 mm in the conventional tool holder). Deformation or breakage of the arm or the like is prevented. Further, since the drawing-in amount is small, there is an advantage that the drawing-in time, that is, the tool changing time is shortened.

After the tool holder is mounted on the machine tool in this way, the spindle 1 of the machine tool is rotated, and machining is performed by the cutting tool 23 mounted on the tool holder. At this time, the coolant supplied from the coolant supply device of the spindle 1 is supplied to the cutting tool 23 through the tool insertion hole 15 of the pull stud 14 and the coolant supply hole 26 of the draw bolt 24.

At the time of this processing, the elastic member 6 is a combination of the compressed body 12 and the non-compressed body 13 without any gap in the axial direction. Unlike the case where disc springs are alternately combined in the opposite direction, chatter due to resonance is eliminated. Further, since a plurality of combinations of the compressed body 12 and the non-compressed body 13 are joined, rigidity and vibration damping properties are improved and resonance is less likely to occur as compared with a single-piece joined body.

Furthermore, since the elastic member 6 is formed in an annular shape and its inner peripheral surface is in contact with the outer peripheral surface of the shank portion 4, the elastic member 6 can be prevented from oscillating even during high-speed rotation, and vibration is generated. Can be prevented. When removing the tool holder from the machine tool, after the tool change arm of the automatic tool changer grasps the tool holder, the pulling means 7 releases the clamp of the pull stud 14 and the rear end side of the shank 4 (pull stud 14). ).

At this time, a shape restoring force is always applied to the sleeve 3 in the radially expanding direction against the reduced diameter.
This action assists in pushing the sleeve 3 out of the tapered hole of the main shaft 1. Moreover, since the sleeve 3 is smoothly moved in the axial direction relative to the shank portion 4 by the lubricant securely held by the lubricant groove 4a, the removal of the tool holder is easy and reliable. Is done.

Accordingly, as shown in FIG. 6, the close contact between the tapered hole 2 of the main shaft 1 and the tapered surface of the sleeve 3 and between the end surface of the main shaft 1 and the flange portion 5 of the tool holder are released, and a gap is formed in each. It is formed. In this state, compressed air is supplied from the compressed air supply device (not shown) in the main shaft 1 into the tapered hole 2, and this compressed air cleans each gap.

The present invention is not limited to the above embodiment. For example, the number of the inner grooves 3a provided in the sleeve 3 is not limited at all. Also the inner groove 3
a is formed straight in parallel with the sleeve axis,
It can be formed so that the groove width is constant. It is also possible to change the width of the inner groove 3a.

In the case where a plurality of inner grooves 3a are provided in the sleeve 3, one of the inner grooves 3a is provided as shown in FIG.
It is possible to provide a slit 35 at a for penetrating the sleeve thickness along the groove bottom. In this case, the slit 35 is filled with an elastic filler 36 made of silicon, nylon, rubber, or another material. Further, the inner groove 3 a without the slit 35 is formed to have a wider groove width than the inner groove 3 a with the slit 35.

In this manner, when the tool holder is fitted into the main shaft 1 of the machine tool, the diameter of the sleeve 3 can be reduced by reducing the opening width of the slit 35, so that the diameter of the sleeve 3 can be reduced. The advantage of being easy and reliable is obtained. In addition, the elastic filler 36 can prevent dust and the like from entering the slit 35.

As shown in FIG. 8, since the slit 35 is positioned at the bottom of the inner groove 3a, the elastic filler 36 filled in the slit 35 also fills the inner groove 3a. Has become. Therefore, even if the tool holder is rotated at a high speed, the elastic filler 36 in the slit 35 can be prevented from being displaced, popped out, deformed, or the like due to centrifugal force.

The elastic filler 36 packed in the slit portion 35 is compressed or compressed when the opening width of the slit portion 35 is enlarged or reduced with respect to the sleeve 3. Since it returns to the previous shape, the sleeve 3
Has no adverse effect on the action of reducing the diameter. In addition, when the pulling means 7 provided inside the main shaft 1 grips the pre-stud 14 of the tool holder and pulls inward in the axial direction of the main shaft 1, the sleeve 3 is reduced in diameter while compressing the elastic filler 3b. I will be. Therefore, the elastic filler 36 stores an elastic force for expanding the sleeve 3.

The elastic force of the elastic filler 36 cooperates with the generation of the repulsive force of the elastic member 6 which is compressed in the axial direction, thereby forming the tapered surface of the sleeve 3 and the tapered hole 2 of the main shaft 1 together. Helps to make a strong taper contact. On the other hand, also when the tool holder is removed from the main spindle 1 of the machine tool, the elastic force of the elastic filler 3b assists the operation of pushing the sleeve 3 out of the tapered hole of the main spindle 1 through the expanding action of the sleeve 3. Will do.

The slit 35 can be formed so as not to pass through in the axial direction of the sleeve 3. In this case, the slit 35 can be provided for the plurality of inner grooves 3a. When the slits 35 are provided in the plurality of inner grooves 3a, all the slits 3
5 can be arranged closer to the larger diameter end or smaller diameter end of the sleeve 3, or their arrangement can be alternately changed.

In addition, the shank part 4 of the tool holder is
A plurality of recesses are formed equidistantly from the outer peripheral surface, and each of the recesses can form the lubricant enclosing portion 4a. The preload providing means 17
It consists of a spacer 28 fixed to the shank end by a bolt 27. By adjusting the thickness of the spacer 28, the assembly distance between the sleeve 3 and the flange 5 is made constant.

The preload applying means 17 may adjust the thickness or the number of the non-compressed bodies 13 of the elastic member 6. Alternatively, the sleeve 3 and the flange portion 5 are formed by a combination of a member for adjusting the thickness or the number of the non-compressed bodies 13 of the elastic member 6 and a member for adjusting the thickness of the spacer 28.
The assembly distance may be constant.

[0052]

As is apparent from the above description, according to the present invention , the sleeve which fits in the tapered hole of the main shaft of the machine tool and comes into surface contact with the sleeve is provided on the inner peripheral surface with the sleeve axis. Inside
A groove is formed, and the inner groove of the sleeve extends in the circumferential direction of the sleeve.
A plurality of evenly arranged grooves are provided, one of which has a groove bottom
A slit is formed through the sleeve thickness along the
This slot is filled with an elastic filler,
In addition, with the sleeve alone, the dynamic balance around the axis is
Since being taken, unlike slotted portion provided in the sleeve of the conventional tool holder, there is nothing to open toward the tapered surface of the sleeve outer peripheral portion. for that reason,
No dust or the like enters the inner groove.

Thus, the diameter of the sleeve is not insufficiently reduced at the next use of the tool holder, and the required amount of the tool holder can be drawn into the main spindle of the machine tool. Therefore, the flange end face of the tool holder is securely in contact with the spindle end face of the machine tool, and the connection between the sleeve and the shank portion is also firmly performed. Deflection can be prevented.

A plurality of inner grooves of the sleeve are provided equidistantly in the circumferential direction of the sleeve, and each inner groove is inclined with respect to the axis of the sleeve. Ru can der be along formed by maintaining a constant thickness structure. With this configuration, the sleeve is balanced around the rotation axis, and the rotation is less likely to be uneven, so that the sleeve is suitable for high-speed rotation.

A plurality of inner grooves of the sleeve are provided equidistantly in the circumferential direction of the sleeve, and one of the inner grooves is formed with a slit portion penetrating the thickness of the sleeve along the bottom of the groove. With a structure in which an elastic filler is packed in the slit
Have been. With this configuration, the slit portion has an advantage that the sleeve is easily reduced in diameter when the tool holder is fitted to the main shaft of the machine tool. It can be prevented from entering.

[0056] than said groove width of the inner groove of slit portion is provided, it is <br/> not preferable that formed wider towards the groove width of the other inner groove. With this configuration, the thickness of the thinned portion corresponding to the slit portion and the thickness of the thinned portion obtained by widening the groove width are balanced in the circumferential direction of the sleeve, and rotation unevenness is less likely to occur in the sleeve. It will be.

[Brief description of the drawings]

FIG. 1 is an exploded side view showing an embodiment of a tool holder according to the present invention.

FIG. 2 is an enlarged view taken along line AA of FIG. 1;

FIG. 3 is an enlarged sectional view taken along line BB of FIG. 2;

FIG. 4 is a side sectional view showing a mounting state of a tool holder.

FIG. 5 is an enlarged view of a portion C in FIG. 4;

FIG. 6 is a side sectional view showing a removal state of the tool holder.

FIG. 7 is a front view (a view corresponding to FIG. 2) showing another embodiment of the sleeve.

FIG. 8 is an enlarged sectional view of a main part (slit part) of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main shaft of machine tool 2 Tapered hole 3 Sleeve 3a Inner groove 4 Shank part 5 Flange part 6 Elastic member 35 Slotting part 36 Elastic filler

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-104625 (JP, A) JP-A-5-154705 (JP, A) Fully open 1983-143108 (JP, U) Really open 1988 53605 (JP, U) JP-B-53-8949 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23Q 3/12

Claims (3)

(57) [Claims] 1. A tapered hole (2) in a main shaft (1) of a machine tool.
A sleeve (3) fitted into the sleeve (3); a shank (4) slidably fitted in the sleeve (3); and a shaft (1) provided integrally with the shank (4). In a tool holder having a flange portion (5) contacting an end face and an elastic member (6) for urging the sleeve (3) in a direction away from the flange portion (5), the sleeve (3) includes: An inner groove (3a) is formed on the inner peripheral surface along the axis of the sleeve, and a plurality of inner grooves (3a) of the sleeve (3) are provided equidistantly in the circumferential direction of the sleeve. Inner groove (3a)
A slit (35) is formed along the bottom of the groove so as to penetrate the thickness of the sleeve. An elastic filler (36) is filled in the slit (35). A) a tool holder characterized in that the inner groove (3a) is formed so that a single body is dynamically balanced around the axis; 2. An inner groove (3a) of the sleeve (3) is inclined with respect to the axis of the sleeve, and a portion of the sleeve corresponding to the inner groove (3a) has a constant thickness along the axis of the sleeve. The tool holder according to claim 1, wherein the tool holder is formed as follows. 3. The groove width of the other inner groove (3a) is formed wider than the groove width of the inner groove (3a) provided with the slit portion (35). Claim 1
Tool holder as described.