JPH08108302A - Tool holder - Google Patents

Abstract

PURPOSE: To easily and surely attach or detach a tool holder to/from a machine tool when a tool like an end mill is attached to the machine tool like a machine center with the aid of the tool holder. CONSTITUTION: A spiral groove 4a is formed around a shank part 4 of a tool holder, and a lubricant is enclosed in a space between the inside of the spiral groove 4a and an inner peripheral surface of a tapered sleeve 3. With this, the lubricant is surely held between the shank part 4 and the tapered sleeve 3 for many years. In addition, in the tapered sleeve 3, a slotted part 3a, which runs along the axial direction, is formed in a part of the peripheral part of the sleeve 3, and the slotted part 3a is stuffed with an elastic member 3b. Since this elastic member 3b constantly energizes the tapered sleeve 3 in the diameter- enlarging-direction, an escape of the tool holder from a hole, which is made in a spindle of a machine tool, can be made easily and surely.

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 spindle of a machine tool.

[0002]

2. Description of the Related Art In a machine tool such as a machining center, an automatic tool changing device is provided, and the tool holder having a tool attached thereto can be detachably replaced with a spindle of a machine tool by the automatic tool changing device. Then, the tool holder mounted on the spindle is coupled at one point of contact with the tapered hole of the spindle and the tapered surface of the shank portion of the tool holder, and is pulled inward in the axial direction by the tension means incorporated in the spindle. By strengthening the contact between the tapered hole and the tapered surface, the tool holder is firmly fixed to the spindle. The coupling strength (coupling rigidity) between the spindle and the tool holder affects the machining accuracy. If this joint rigidity is low, heavy cutting and high-speed rotation cannot be endured, and chatter, vibration, tool collapse, and heart runout occur.

In order to improve the bond strength, it is necessary to increase the tensile strength of the tension means, but there is a limit to increasing the tensile force of the tension means. Therefore, as a tool holder designed to increase the coupling rigidity without increasing the pulling force,
For example, those described in Japanese Utility Model Laid-Open No. 63-53605 are known.

This conventional tool holder is provided integrally with a sleeve that fits into a tapered hole of a main shaft of a machine tool, a shank portion that is inserted through the sleeve while allowing relative movement in the axial direction, and the shank portion. It has a flange portion that is brought into contact with the end surface of the main shaft, and an elastic member provided between the flange portion and the sleeve. As the elastic member, a single rubber elastic body forming an annular shape around the shank portion or a disc spring assembly in which a plurality of disc springs are alternately combined in opposite directions is used.

The conventional tool holder is detachably mounted in a taper hole of a spindle of a machine tool by gripping a peripheral groove portion formed on the outer peripheral surface of the flange portion with an arm of an automatic tool changing device. . At the time of this mounting, the taper surface of the sleeve outer peripheral surface is fitted into the taper hole of the main shaft, and a predetermined gap is formed between the main shaft end surface and the flange end surface.

Then, the tool holder is pulled inward by the pulling means installed in the main shaft, so that the flange end surface abuts on the main shaft end surface. At this time, the sleeve is pressed by the elastic member to strengthen the connection with the tapered hole of the main shaft, and the inner diameter of the sleeve is reduced to strengthen the connection between the sleeve and the shank portion. That is, the conventional tool holder is in close contact with the spindle at two points, that is, the taper hole of the spindle of the machine tool and the taper surface of the shank portion of the tool holder, and the spindle end surface and the end surface of the flange portion of the tool holder, and the sleeve. By strengthening the connection between the shank portion and the shank portion, it has been attempted to obtain stronger connection rigidity than that obtained by connecting only one portion of the tapered hole and the tapered surface with the same tensile force.

[0007]

In order to remove the tool holder from the machine tool when exchanging the tool, a pulling means provided in the main shaft of the machine tool applies a shock in the pushing direction to the rear end side of the shank portion of the tool holder. However, in the conventional tool holder, since the taper hole of the spindle of the machine tool and the taper surface of the shank portion (sleeve) of the tool holder are firmly brought into close contact with each other by the pressing action of the elastic member, It required a strong impact force to remove the tool holder from the machine tool in proportion to the strength. However, there is a limit to increasing the impact force of the tension means in the machine tool, and as a result, it has become difficult to remove the tool holder from the machine tool.

Further, when the tool holder is attached to or detached from the machine tool, it is necessary to smoothly move the sleeve in the axial direction with respect to the shank portion of the tool holder. For this purpose, the shank portion and the sleeve are separated from each other. It is necessary to apply lubricating oil in between, but in order to maintain this state, it is necessary to frequently replenish the lubricating oil, for example, every time the tool is changed, and handling and management of the tool holder becomes troublesome. Was there.

On the other hand, in the elastic member, in order to obtain a predetermined sleeve pressing force, it is necessary to increase the compression amount. Then, when the compression amount of the elastic member is increased, when the tool holder is mounted on the spindle by the automatic tool changer,
The gap between the end face of the main shaft and the end face of the flange becomes large, and it is necessary to increase the amount of pulling in of the tension means. Conventionally, the retracted amount was about 3 mm.

As described above, when the retracted amount is large, the tool exchanging arm holding the tool holder largely bends during automatic tool exchanging, which causes damage to the automatic tool exchanging device. Further, there is a problem that the tool exchange time becomes longer as the pulling amount becomes larger. Note that, in the past, since the elastic member is elastically deformed by the large pull-in amount as described above, in the non-compressed state, a predetermined circumferential direction is provided between the inner peripheral surface and the outer peripheral surface of the shank portion. There was a gap. Therefore, the circumferential gap remains even when the elastic member is in a compressed state, which induces the eccentric movement of the elastic member at the time of high-speed rotation to generate vibration.

Therefore, according to the present invention, it is possible to easily and surely attach and detach the tool holder to and from the machine tool when exchanging the tool, prevent damage to the automatic tool exchanging device, and shorten the time required for exchanging the tool. Further, even if the compression allowance of the elastic member is reduced, a sufficient sleeve biasing force can be obtained, and a circumferential gap does not occur during the compression, thereby providing a tool holder that solves the above problems. The purpose is to do.

[0012]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention takes the following technical means. That is, a feature of the present invention is that a sleeve that fits into a tapered hole of a main shaft of a machine tool, a shank portion that is inserted through the sleeve while allowing relative movement in an axial direction, and the shank portion are integrally formed. A flange portion provided and abutting the end surface of the main shaft,
In a tool holder having an elastic member provided between the flange portion and the sleeve, the sleeve has a slit portion formed in a part of a peripheral portion thereof so as to penetrate along the axial direction. And an elastic body is provided in the slit portion.

Further, according to the present invention, in order to eliminate the need for replenishing the lubricant for a long period of time, the shank portion may be provided with a lubricant seal portion which opens toward the inner peripheral surface of the sleeve. Further, in the present invention, in order to facilitate pulling and fixing by the tool holder pulling means, it is possible to provide a preload applying means for applying a preload to the elastic member to make the assembly distance between the sleeve and the flange part constant. .

Further, according to the present invention, in order to reduce the amount of compression and to obtain a large sleeve pressing force, the elastic member is formed in an annular shape, and is composed of an elastic material compression body and a hard material non-compression body. At least one combination can be axially joined. Further, in the present invention, in order to prevent the occurrence of vibration during high-speed rotation, the elastic member may be formed in an annular shape, and the inner peripheral surface thereof is in contact with the outer peripheral surface of the shank portion.

Further, according to the present invention, in order to more effectively prevent the occurrence of vibration during high-speed rotation, the elastic member is formed in an annular shape and is housed in an annular recess formed in the flange portion, Moreover, when the flange portion comes into contact with the end surface of the main shaft, the inner and outer peripheral surfaces thereof may come into contact with the inner and outer peripheral surfaces of the annular recess.

[0016]

Like the conventional tool holder, the tool holder of the present invention is grasped by the arm of the automatic tool changer and detachably mounted in the tapered hole of the spindle of the machine tool. At the time of this mounting, the taper surface of the sleeve outer peripheral surface is fitted into the taper hole of the main shaft, and a predetermined gap is formed between the main shaft end surface and the flange end surface.

Then, the end portion of the flange portion abuts on the end surface of the main shaft by pulling the tool holder inward of the main shaft by the pulling means incorporated in the main shaft. At this time, the sleeve is pressed by the elastic member to strengthen the connection with the tapered hole of the main shaft, and the inner diameter of the sleeve is reduced to strengthen the connection between the sleeve and the shank portion. Then, after the mounting step of the tool holder is completed, the arm of the automatic tool changer releases the grip.

According to the present invention, the slit portion penetrating in the axial direction is provided in a part of the peripheral portion of the sleeve, and the elastic body is provided in the slit portion. When the sleeve is pulled in, the sleeve is in a state in which the elastic body is compressed in the slotted portion while the elastic body is compressed, and in the mounted state, the sleeve can always be applied with a biasing force for expanding the diameter. Further, by filling the inside of the slit portion with the elastic body, invasion of dust from the slit portion is prevented.

Therefore, when the tool holder is removed from the machine tool and a shock is applied to the rear end side of the shank portion of the tool holder by the pulling means, the urging force for expanding the diameter of the sleeve as described above is exerted on the main shaft. This assists the action of pushing the sleeve out of the tapered hole, so that the tool holder can be easily and reliably removed. If a lubricant sealing portion that opens toward the inner peripheral surface of the sleeve is provided on the shank portion, a lubricant (lubricating oil, etc.) is always maintained between the shank portion and the sleeve, There is no need to replenish the lubricant for a long period of time.

By providing a preload applying means for applying a preload to the elastic member to make the assembly distance between the sleeve and the flange part constant, the compression amount of the elastic member can be made constant, and the tool holder pulling means. Makes it easy to pull and fix. The elastic member is formed in a ring shape, and at least one of the compressed body and the non-compressed body
By making the combination of the pairs bonded in the axial direction, the whole thickness is the same as compared with the one made entirely of rubber elastic body or the one made entirely of disc springs. According to the present invention, the amount of compression is smaller, and a larger sleeve pressing force can be obtained.

Therefore, since the compression amount of the elastic member is small,
The amount of pull-in until the end face of the flange portion comes into contact with the end face of the spindle is reduced, deformation of the tool change arm is reduced during automatic tool change, and the tool change time is shortened. Since the elastic member is formed in an annular shape and the inner peripheral surface of the elastic member is brought into contact with the outer peripheral surface of the shank portion, eccentricity does not occur even at high speed rotation, so vibration generation at high speed rotation is prevented. .

The elastic member is formed in an annular shape and is housed in an annular recess formed in the flange portion, and when the flange portion comes into contact with the end face of the main shaft, its inner and outer peripheral surfaces are inside and outside the annular recess. By abutting against the peripheral surface, when the main shaft rotates at high speed, the center vibration of the elastic member is prevented from the inner and outer peripheral surfaces of the annular recess, and the vibration at the time of high speed rotation is prevented more efficiently.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. 2, a tool holder of the present invention comprises a sleeve 3 fitted in a tapered hole 2 of a spindle 1 of a machine tool, a shank portion 4 inserted through the sleeve 3 while allowing relative movement in the axial direction, and the shank. A flange portion 5 which is provided integrally with the portion 4 and is in contact with the end face of the main shaft 1, and the flange portion 5
And an elastic member 6 provided between the sleeve 3 and the sleeve 3.

The spindle 1 of the machine tool is internally equipped with a pulling means 7 for pulling in a tool holder mounted in the tapered hole 2 of the spindle 1. Further, 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 inner and outer peripheral surfaces, the outer peripheral surface of which is formed into a tapered surface, and the inner peripheral surface of which is formed into a straight surface. As shown in FIG. 1, the sleeve 3 is provided with a slit portion 3a that axially penetrates a part of the peripheral wall portion. This slot 3a
Has a gentle slope along the axial direction. Further, inside the slotted portion 3a, there is provided a diameter-expanding urging member 3b (elastic body) formed of an elastic material such as silicon, nylon, rubber or the like. Therefore, the urging force that tends to increase the diameter always acts on the sleeve 3. In the present embodiment, the diameter enlarging biasing member 3b is provided with the slit portion 3a so as to form a groove on the outer peripheral surface of the sleeve 3 over the entire axial length.
Although it is provided on the back side of the above, of course, it may be provided so as to fill the slot portion 3a.

The taper angle of the taper provided on the outer peripheral surface of the sleeve 3 is the same as the taper angle of the taper hole 2 of the main shaft 1. This taper is made to be performed at a gentler inclination than 7/24 (about 16 °), which is generally used as the inclination, and preferably 12 °. In this embodiment, 1 /
A slope of 10 (about 6 °) was adopted. The shank part 4
Is formed at one end of the holder body 8, and the outer peripheral surface of the shank portion 4 is formed into a straight surface which is closely fitted to the inner peripheral surface of the sleeve 3 so as to be slidable in the axial direction.

The shank portion 4 has a lubricant sealing portion 4a having a groove shape so as to draw a spiral around the outer peripheral surface thereof.
(See FIG. 1) are formed. Therefore, when the sleeve 3 is fitted in the shank portion 4, the lubricant sealing portion 4a opens to face the inner peripheral surface of the sleeve 3, and the lubricant (lubricating oil or grease) is inserted therein. Can be enclosed. The lubricant sealed in the lubricant sealing portion 4a is retained for a long period of time without being reduced or lost until the sleeve 3 is removed from the shank portion 4, which does not hinder the operation.

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

The end surface of the flange portion 5 on the shank portion side is formed into a flat surface that comes into contact with the end surface of the spindle 1 of the machine tool. An elastic member mounting seat 11 is formed on the inner peripheral side of the flat surface of the flange portion 5. The mounting seat 11 is composed of an annular recess formed in the flat surface. As shown in FIG. 3, the elastic member 6 is formed in an annular shape, is housed in the recess of the mounting seat 11, and is in contact with the end surface of the sleeve 3. The inner peripheral surface of the annular elastic member 6 is in close contact with the outer peripheral surface of the shank portion 4, and the outer peripheral surface thereof has a predetermined gap with the inner peripheral surface of the recess of the mounting seat 11. That is, when the flange portion 5 contacts the end surface of the main shaft 1, the inner and outer peripheral surfaces of the annular elastic member 6 are brought into contact with the inner and outer peripheral surfaces of the annular recess 11 (mounting seat).

The elastic member 6 is a compression body 12 made of an elastic material.
And an incompressible body 13 made of a hard material are joined together in the axial direction without any gap. The compression body 12 is made of an elastic material such as urethane-based soft resin or rubber, fluorine-based or other soft resin, or other synthetic rubber. In this embodiment, the wall thickness is 1 mm.

The non-compressed body 13 is formed of a hard material such as a metal plate such as a steel plate. In this embodiment, the wall thickness is 0.2 mm. In this embodiment, a total of 5 combinations of the compressed body 12 and the non-compressed body 13 are joined. Therefore, the total thickness of the elastic member 6 is 6
mm. A pull stud 14 is screwed onto the end surface of the tool holder body 8 on the shank side. A tool insertion hole 15 is provided so as to penetrate the shaft center of the pull stud 14. An outer peripheral portion of the pull stud 14 has a protruding portion 16 having a diameter larger than the outer diameter of the shank portion 4, and the protruding portion 16 prevents the sleeve 3 from coming off. Preloading means 17 is interposed between the protrusion 16 and the sleeve 3.

The preload applying means 17 applies a preload to the elastic member 6 so that the assembly distance between the end surface of the sleeve 3 and the flat surface of the flange portion 5 is constant. In this embodiment, this preload applying means 17
Is composed of a plurality of spacers. That is, by adjusting the thickness of the spacer, 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.

The side of the holder body 8 opposite to the shank portion side of the flange portion 5 is formed as a tool holding portion 18 projecting forward of the flange portion 5. The tool holding portion 18 has a collet holding hole 19 that is open at the front end surface.
Are concentrically provided. The collet holding hole 19 is formed in a gentle taper surface, and the taper collet 20 is mounted in the holding hole 19. This taper collet 20
Has a tool holding hole 21 concentrically on its tip end side and a female screw portion 22 concentrically on its rear end. A cutting tool 23 such as an end mill or a drill is detachably inserted and held in the tool holding hole 21.

A draw bolt 24 is rotatably held in the axial center of the tool holder body 8 with its axial movement constrained, and the threaded portion of the draw bolt 24 is of the taper collet 20. It is screwed into the female screw portion 22.
A tool engaging portion 25 is recessed in the head portion of the draw bolt 24. A coolant supply hole 26 is provided through the axial center of the draw bolt 24.

A tool such as a hexagonal wrench is inserted through the tool insertion hole 15 of the pull stud 14 and the tool is engaged with the tool engaging portion 25 of the draw bolt 24 to rotate the draw bolt 24. By doing so, the taper collet 20
Moves relative to the collet holding hole 19 in the axial direction. By the movement of the taper collet 20 in the axial direction, the tool 23 inserted into the tool holding hole 21 is gripped or released.

According to the embodiment having the above-mentioned structure, the tool holder of the present invention having the tool 23 mounted thereon is mounted in the magazine (not shown) of the automatic tool changing device. The tool change arm of the automatic tool changer grips the fitting groove 10 of the tool holder,
The tool holder is taken out of the magazine, conveyed to the spindle 1 of the machine tool, and then mounted in the tapered hole 2 of the spindle 1.

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

Next, the pulling means 7 incorporated in the spindle 1 holds the pre-stud 14 and pulls the holder body 8 inward of the spindle. Due to this pulling, the shank portion 4 and the flange portion 5 try 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, due to the difference in the movement resistance of the inner and outer peripheral surfaces of the sleeve 3, relative movement in the axial direction occurs between the inner surface of the sleeve and the outer peripheral surface of the shank portion, and the sleeve 3 contracts while the expansion energizing member 3b is compressed. At the same time, the elastic member 6 is also compressed in the axial direction.

Then, the flat surface of the flange portion 5 contacts the end surface of the main shaft (see FIG. 2). At this time, since the sleeve 3 is axially pressed by the repulsive force due to the compression of the elastic member 6, this pressing force and the diameter expansion action of the diameter expansion biasing member 3b cause the taper surface of the sleeve 3 and the main shaft 1 to move. A strong taper contact connection with the taper hole 2 is obtained. Then, the inner diameter of the sleeve 3 is reduced by tightening due to this taper contact, and the shank portion 4 is firmly gripped.

After the pulling step is completed, the grip of the tool changing arm is released, and the arm returns to the original standby position. In the mounting process described above, in the present embodiment, the retracting amount of the tool holder is made very short by 0.5 mm by the preload imparting means 17, so that the deformation amount of the tool exchanging arm is reduced and the arm and the like are not damaged. There is no fear. Also, since the amount of pull-in is small,
Since the pull-in time is shorter than that of the conventional 3 mm tool, the tool exchange time can be shortened.

After the mounting step is completed, the spindle 1 of the machine tool starts rotating, and the work is cut by the tool 23 held by the tool holder. At the time of this cutting, the coolant supplied from the coolant supply device of the spindle 1 is the tool insertion hole 15 of the pull stud 14 and
It is supplied to the tool 23 through the coolant supply hole 26 of the draw bolt 24.

In this rotation and cutting process, the elastic member 6
Is a combination of the compressed body 12 and the non-compressed body 13 with no gap in the axial direction, so chatter due to resonance does not occur. In addition, the compressed body 12 and the non-compressed body 1
Since it is made by joining a plurality of combinations with No. 3, the rigidity and the vibration damping property are improved as compared with the single set joining,
Resonance is less likely to occur.

Further, since the elastic member 6 is formed in an annular shape and the inner peripheral surface thereof is brought into contact with the outer peripheral surface of the shank portion 4, the runout of the elastic member 6 does not occur even when rotating at high speed. Therefore, generation of vibration during high speed rotation is prevented. When removing the tool holder from the machine tool, after the tool change arm of the automatic tool changer grips the tool holder,
The pulling means 7 releases the clamp of the pull stud 14 and applies an impact to the rear end side of the shank portion (pull stud 14).

At this time, the sleeve 3 has a diametrical expansion biasing member 3
Since the urging force of constantly expanding the diameter is applied by b, this urging force assists the operation of pushing the sleeve 3 out of the tapered hole of the main shaft 1. Moreover, since the sleeve 3 is in a state in which relative movement in the axial direction is smoothly performed with respect to the shank portion 4 by the lubricant filled and held in the lubricant sealing portion 4a, removal of the tool holder Is easy and secure.

Therefore, as shown in FIG. 4, the close contact between the inner surface of the tapered hole of the main spindle 1 and the tapered surface of the sleeve 3 and between the end surface of the main spindle 1 and the flange portion 5 of the tool holder is released,
A gap is formed in each. In this state, compressed air is supplied from the compressed air supply device (not shown) in the main shaft 1 into the tapered holes, so that the compressed air cleans the gaps. In addition, in the tool holder of this embodiment, when an impact is applied to the rear end side of the shank portion, the contact between the inner surface of the taper hole of the spindle 1 and the taper surface of the sleeve 3 is released momentarily. However, the close contact between the end surface of the spindle 1 and the end surface of the flange portion 5 of the tool holder is released first. At this time, the compressed air from the compressed air supply device passes through the slit portion 3a of the sleeve 3 (through the gap between the diameter expansion urging member 3b provided in the slit portion 3a and the inner surface of the tapered hole 2). The end surface of the flange portion 5 can be made to flow intensively, and the end surface of the flange portion 5 can be effectively cleaned.

In this embodiment, the taper of the sleeve is set to 1
By making the taper gradual to / 10, high joint rigidity could be obtained. That is, as shown in FIG. 5, it was investigated how the taper angle Tp of the sleeve 3 and the pulling force Pt of the pulling means influence the inclination θ of the shaft center when the tool holder is mounted on the spindle. As is clear from this FIG. 5, the inclination θ of the tool holder shows a tendency that the taper angle Tp becomes smaller as the taper angle Tp becomes looser even when the pulling force Pt is variously changed. That is, it was found that the smaller the taper angle Tp, the higher the joint rigidity. The taper angle Tp is preferably 12 ° or less.

FIG. 6 shows another embodiment of the present invention, in which the preloading means 17 is different from that of the above embodiment. That is, the preload applying means 17 is composed of the spacer 28 fixed to the end of the shank portion by the bolt 27. By adjusting the thickness of the spacer 28, the assembly distance between the sleeve 3 and the flange portion 5 is made constant.

The preload applying means 17 is not limited to the above-mentioned embodiments, but may be one which adjusts the thickness or the number of the non-compressed bodies 13 of the elastic member 6. Alternatively, the assembly distance between the sleeve 3 and the flange portion 5 can be made constant by a combination of adjusting the thickness or number of the non-compressed bodies 13 of the elastic member 6 and adjusting the thickness of the spacer 28. It may be.

FIG. 7 shows still another embodiment of the present invention, in which the structure of the elastic member 6 is different from that of each of the aforementioned embodiments. That is, the elastic member 6 is composed of an assembly of the compression body 41 using an annular disc spring and the non-compression body 42 using a flat washer. In the uncompressed state, the compression body 41 is
Although it is elastically deformable with a gap with the inner and outer peripheral surfaces of the recess of the mounting seat 11, the inner and outer peripheral surfaces of the compression body 41 are in a compressed state where the end surface of the flange portion 5 and the end surface of the main shaft 1 are in contact with each other. Is sized to contact the inner and outer peripheral surfaces of the recess of the mounting seat 11. Further, the inner peripheral surface of the non-compressed body 42 is dimensioned to be closely fitted to the outer peripheral surface of the shank portion 4 (the inner peripheral surface of the annular recess 11).

The non-compressed body 42 is selected to have an appropriate thickness (or mounted in an arbitrary number), and the compression amount of the compressed body 41 can be adjusted. Therefore,
According to this comparative example, since the inner and outer peripheral surfaces of the compression body 41 of the elastic member 6 are in contact with the inner and outer peripheral surfaces of the recess of the mounting seat 11 in the rotation and cutting steps of the machine tool,
Since the runout of the elastic member 6 does not occur, vibration is prevented from occurring during high speed rotation.

The present invention is not limited to the above embodiments. For example, in the sleeve 3, the slit portion 3a may be formed straight so as to be parallel to the axial direction. Further, in the shank portion 4, it is possible to form a plurality of concave portions on the outer peripheral surface thereof in an equidistant manner, and to form the lubricant encapsulating portion 4a by these concave portions.

Further, as shown in FIG. 8, the lubricant enclosing portion 4a can be formed as a saw-tooth groove which is continuous over the entire outer peripheral surface of the shank portion 4. In addition, the elastic member 6
The thickness of the compressed body 12, 41 or the non-compressed body 13, 42, the number of sheets to be used, etc. are not limited, and can be appropriately changed according to the diameter and purpose of the tool 23, rotation speed, pulling force, etc. is there. Further, as the sleeve 3, the above-mentioned actual opening 6
Various materials described in JP-A-3-53605 can be adopted.

[0053]

According to the present invention, a slit portion penetrating in the axial direction is provided in a part of the peripheral portion of the sleeve, and an elastic body is provided in the slit portion, so that the tool holder is mounted on the spindle. When retracted inward, the sleeve obtains a state in which the elastic body is compressed while being compressed in the slot,
The urging force for expanding the diameter can be constantly applied to the sleeve in the mounted state.

Therefore, when the tool holder is detached from the machine tool and a shock is applied to the rear end side of the shank portion of the tool holder by the pulling means, the urging force for expanding the diameter of the sleeve as described above is exerted on the main shaft. This assists the action of pushing the sleeve out of the tapered hole, so that the tool holder can be easily removed and the reliability of the tool holder removal work can be improved.

Further, dustproofness can be realized by filling the inside of the slotted portion with an elastic body. By providing a lubricant sealing portion that opens toward the inner peripheral surface of the sleeve on the shank portion, it is possible to keep the lubricant (lubricating oil, etc.) between the shank portion and the sleeve. The axial movement of the shank can be performed smoothly and surely, and it is not necessary to replenish the lubricant for a long period of time.

By providing a preload applying means for applying a preload to the elastic member to make the assembling distance between the sleeve and the flange portion constant, the compression amount of the elastic member can be made constant, and the tool holder pulling means. Can be easily pulled and fixed. The elastic member is formed in an annular shape, and at least one combination of the compressed body and the non-compressed body is joined in the axial direction to form a rubber elastic body as a whole,
If the entire thickness is the same as in the case where the whole body is made up of only disc springs, the compression amount of the present invention is smaller and a larger sleeve pressing force can be obtained.

Therefore, since the amount of compression of the elastic member is small,
It is possible to reduce the amount of pull-in until the end face of the flange portion comes into contact with the end face of the spindle, and it is possible to reduce the deformation of the tool change arm during automatic tool change, and also to shorten the tool change time. Since the elastic member is formed in an annular shape and the inner peripheral surface of the elastic member is brought into contact with the outer peripheral surface of the shank portion, the runout does not occur even at high speed rotation, so that the occurrence of vibration at high speed rotation is prevented. You can

The elastic member is formed in an annular shape and is housed in an annular concave portion formed in the flange portion, and when the flange portion comes into contact with the end surface of the spindle, its inner and outer peripheral surfaces are inside and outside the annular concave portion. When the main shaft is rotated at a high speed, the center vibration of the elastic member can be prevented from the inner and outer peripheral surfaces of the annular recess by contacting the peripheral surface, and the vibration at the high speed rotation can be prevented more efficiently. it can.

[Brief description of drawings]

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

FIG. 2 is a side sectional view showing a mounting state of a tool holder.

FIG. 3 is an enlarged view of part A of FIG.

FIG. 4 is a side sectional view showing how the tool holder is removed.

FIG. 5 is a graph showing a change in rigidity with a taper angle at which the outer peripheral surface of the sleeve and the inner peripheral surface of the tapered hole are in contact with each other.

FIG. 6 is a side sectional view showing a modified example of the preload applying means.

FIG. 7 is a side sectional view showing a modified example of the elastic member.

FIG. 8 is a side view showing another embodiment of the holder body.

[Explanation of symbols]

 1 spindle of machine tool 2 taper hole 3 sleeve 3a slitting portion 3b diameter expansion urging member 4 shank portion 4a lubricant sealing portion 5 flange portion 6 elastic member 11 annular recess (mounting seat) 12 compression body 13 incompressible body 17 Preloading means

Claims (6)

[Claims] 1. A taper hole (2) for a spindle (1) of a machine tool.
And a shank portion (4) inserted into the sleeve (3) while allowing relative movement in the axial direction.
And a flange portion (5) which is provided integrally with the shank portion (4) and contacts the end surface of the main shaft (1), and is provided between the flange portion (5) and the sleeve (3). In the tool holder having the elastic member (6), the sleeve (3) is provided with a slitting portion (3a) penetrating along the axial direction in a part of a peripheral portion of the sleeve (3),
A tool holder characterized in that an elastic body (3b) is provided in the slot portion (3a). 2. A lubricant seal portion (4a), which is open to the inner peripheral surface of the sleeve (3), in the shank portion (4).
The tool holder according to claim 1, wherein the tool holder is provided. 3. A preload applying means (17) is provided for applying a preload to the elastic member (6) to make the assembly distance between the sleeve (3) and the flange portion (5) constant. The tool holder according to claim 1 or 2. 4. The elastic member (6) is formed in an annular shape, and at least one combination of an elastic material compression body (12) and a hard material non-compression body (13) is axially joined. The tool holder according to any one of claims 1 to 3, characterized in that 5. The elastic member (6) is formed in an annular shape, the inner peripheral surface of which is in contact with the outer peripheral surface of the shank portion (4). Tool holder described in. 6. The elastic member (6) is formed in an annular shape, and an annular recess (1) formed in the flange portion (5).
1), and when the flange portion (5) contacts the end surface of the main shaft (1), the inner and outer peripheral surfaces thereof contact the inner and outer peripheral surfaces of the annular recess (11). The tool holder according to any one of claims 1 to 3, wherein