JP2000158269A - Tool holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the manufacture of a tool holder exchangeably attached to a machining device main spindle and to eliminate the deviation of the axial center in machining. SOLUTION: A tool holder 15 exchangeably mounted in a tapered hole 13 formed in a main spindle 10 of a machining device is constituted of a shaft body 17 projected rear part of a body 16 to which the tool is attached, a tapered sleeve 21 having the outer surface formed into a conical shape matching with the tapered hole 13 and having the internal circumferential face fitted with the shaft body 17, an elastic ring 23 externally fitted to the shaft body 17, axially compressed against the elastic force so as to energize in the tapered hole 13 side, when the tapered sleeve 21 is fitted to the shaft body 17 and inserted into the tapered hole 13. If the diameter of the tapered hole 13 is enlarged by the centrifugal force, the tapered sleeve 21 moves axially by that extent by the elastic force of the elastic ring 23 so that the integrity of the shaft body 17 and the main spindle 10 is held.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tool holder which can be exchangeably mounted on a processing machine, and more particularly, to a tool holder attached to a main shaft of a processing machine, and the main shaft and the tool holder are integrally rotated at a high speed. Also, the present invention relates to a tool holder capable of maintaining its integrity without shifting the axis.

[0002]

2. Description of the Related Art In an NC machine or the like, for example, when holes of various diameters are drilled in a workpiece, a robot or the like automatically attaches a drill having a corresponding diameter to a main shaft of the processing machine. In this case, since it is difficult to directly mount the drill so that its axis coincides with the main shaft, it is necessary to mount drills of various diameters on the respective tool holders in advance and mount the corresponding tool holders on the processing machine. It has become.

FIG. 8 is a configuration diagram of a conventional tool holder described in Japanese Patent Application Laid-Open No. 7-96436. The main shaft 2 rotatably held on the frame 1 of the processing machine includes:
A conical tapered hole 3 is provided. Tool holder 5
Is provided with a conical shank portion 6 at the back thereof which is aligned with the tapered hole 3.

[0004] A robot (not shown) is provided with a tool holder 5.
Is inserted into the tapered hole 3 of the spindle, and the pull stud 7 at the tip of the shank 6 is pulled into the pulling tool 4 on the processing machine until the back end face of the main body 8 of the tool holder 5 contacts the spindle tip face 2a. The tool holder 5 is integrally fitted to the main shaft 2 such that the axes thereof coincide with each other. A tool such as a drill (not shown) is attached to the side opposite to the pull stud 7.

The shank 6 of the prior art is formed as a hollow body, and the thickness T of the peripheral wall is formed uniformly over the entire circumference and the entire length of the shank 6. The robot inserts the outer peripheral surface 6a of the shank portion 6 into contact with the inner peripheral surface 3a of the tapered hole 3, and furthermore, the puller 4
Is drawn in by a strong force until the back end surface 8a of the main body 8 comes into contact with the main shaft front end surface 2a, whereby the shank portion 6 is uniformly reduced in diameter, and the tool holder 5 is integrally and closely held to the main shaft 2.

[0006]

Since the main shaft of the processing machine rotates at a very high speed of 20,000 revolutions per minute, even if it is made of stainless steel, the influence of the centrifugal force cannot be ignored, and the tapered hole 3 of the main shaft is not formed. Expand the diameter by centrifugal force. Even in such a case,
The tool holder 5 needs to maintain a high degree of integrity so that the main shaft 2 always coincides with the axis, and even a slight deviation of the axis adversely affects machining accuracy. Therefore, the spindle 2
The structure of the main shaft fitting portion of the tool holder 5 to be mounted on the main body becomes important.

In the prior art described above, when the puller 4 pulls in the tool holder 5, the back portion 8a of the main body 8 is
And the thickness T of the peripheral wall is uniformly formed so that the entire shank portion 6 is uniformly reduced in the axial direction. However, even if the entirety is formed uniformly, the accuracy is a problem. In order to uniformly reduce the diameter of the shank portion 6 and maintain a high degree of integration with the main spindle even during ultra-high-speed rotation, high-precision uniform processing is required. become.

It is an object of the present invention to provide a tool holder which can easily form and form a main shaft fitting portion and can maintain a high degree of integrity with a main shaft even under ultra-high speed rotation.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a tool holder which is interchangeably mounted in a tapered hole formed in a main shaft of a processing machine, comprising a shaft protruding from a back of a main body to which a tool is mounted. A tapered sleeve whose outer surface is formed in a conical shape matching the tapered hole, and whose inner peripheral surface is fitted to the shaft; and wherein the tapered sleeve is fitted to the shaft and fitted to the shaft. This is achieved by providing an elastic ring that is compressed against the elastic force in the axial direction when inserted into the tapered hole and biases the tapered sleeve toward the tapered hole.

In order to hold the shaft body integrally with the main shaft, it is easy to process and form the tapered sleeve interposed between them.
In addition, since the tapered sleeve is always urged toward the tapered hole by the elastic force of the elastic ring in the completed state, even if the diameter of the tapered hole is expanded by centrifugal force, the tapered sleeve moves with the urging force. The integrity of the shaft and the main shaft is maintained. Therefore, the axis does not shift.

[0011]

An embodiment of the present invention will be described with reference to the drawings. 1 to 4 are configuration diagrams of a tool holder according to an embodiment of the present invention. Spindle 1 on existing machine
0, a hole 11 is formed along the central axis, a pulling tool 12 is provided therein, and a conical tapered hole 13 is continuously provided on the tip end side of the hole 11 on the main shaft. ing. The tool holder 15 is detachably inserted into the tapered hole 13 of the main shaft 10.
Is attached.

A metal tool holder 15 according to the present embodiment.
Is a large-diameter main body 16 that is in contact with the distal end face 10a of the main shaft 10.
And a shaft 17 protruding from the back of the main body 16. The shaft body 17 includes a middle diameter portion 17a cut from the main body 16 and a small diameter portion 17b connected to the back of the middle diameter portion 17a and cut from the middle diameter portion 17a. A screw hole 19 is provided in the shaft, and a pull stud 20 is screwed into the screw hole 19. A metal tapered sleeve 21 is fitted on the shaft 17. Since the configuration of the tool holder main body 16 on the side opposite to the pull stud 20, that is, the side on which the tool is mounted, is not shown because it is well known.

The tapered sleeve 21 is formed to be extremely thin compared to the thickness of the main shaft 10 and the diameter of the shaft 17 as shown in the figure. Further, the outer peripheral surface is formed in a conical shape which is aligned with the inner peripheral surface of the tapered hole 13, and the center axis thereof has a medium diameter hole 21a which is aligned with the outer peripheral surface of the medium diameter portion 17a, and A small-diameter hole 21b matching the outer peripheral surface of the communication small-diameter portion 17b is formed. A ring groove 21c is formed in the inner peripheral portion of the opening end of the medium diameter hole 21a of the tapered sleeve 21.

A rigid ring having a rectangular cross section, for example, a metal ring 22, which fits into the ring groove 21c, is externally fitted to the middle diameter portion 17a of the tool holder 15, and the outer diameter is the same as the outer diameter of the middle diameter portion 17a. An elastic ring 23 made of synthetic resin having the same rectangular cross section as the outer diameter of the small-diameter portion 17b is externally fitted to the small-diameter portion 17b, and the tapered sleeve 21 is mounted on the tool holder 1 from above.
5 is fitted around the middle diameter portion 17a and the small diameter portion 17b. The axial thickness of the rigid ring 22 is greater than the axial depth of the ring groove 21c.

An O-ring 24 having a diameter slightly larger than that of the ring 22 is inserted between the opening end face of the medium diameter hole 21a of the tapered sleeve 21 and the end face 16a of the tool holder body 16 on the main shaft side. The opening-side end of the hole 21b is locked by a ring-shaped stopper 25 fixed to the outer periphery of the small-diameter portion 17b of the tool holder 15, and the tapered sleeve 21
Are not detached from the tool holder 15.

The tool holder 15 having the above-described configuration is connected to the main shaft 10.
, First, the medium diameter portion 17a of the holder 15
A main shaft fitting portion composed of the small diameter portion 17b, the tapered sleeve 21, and the like is inserted into the tapered hole 13 of the main shaft 10, and the state shown in FIG.

Next, when the pull stud 20 is gripped by the puller 12 and the tool holder 15 is pulled in, the state shown in FIG. 2, ie, the outer peripheral surface 21 f of the tapered sleeve 21 is changed to the inner peripheral surface of the tapered hole 13. Is brought into contact with. Further, when the puller 12 pulls the tool holder 15 in the direction of arrow A, the O-ring 24 and the elastic ring 23 are compressed, and the ring groove 21 is compressed.
A state where the gap between c and the metal ring 22 disappears, that is, a state shown in FIG. In this state, a slight gap 26 remains between the back end face 16a of the tool holder body 16 and the spindle tip face 10a.

Further, the pulling tool 12 moves the tool holder 15 in the direction indicated by the arrow A.
The main body 16 presses the metal ring 22 in the direction of arrow A to pull the tapered sleeve 21 into the tapered hole 1.
3, the gap 26 is eliminated, and the main body 16 of the tool holder 15 is firmly adhered to the main shaft 10 as shown in FIG. In this state, the stopper 25 is attached to the tapered sleeve 21.
The elastic ring 23 is further compressed against the resilience by a certain distance from the end on the side of the pull stud 20. That is, when the tool holder 15 is mounted on the main shaft 10, the tapered sleeve 21 is always urged toward the small diameter side of the tapered hole 13 by the elastic force of the elastic ring 23.

In the state shown in FIG. 4, the tapered sleeve 21 is elastically deformed by receiving a strong reaction force in the radial direction from the main shaft 10 and slightly reduced in diameter. Thereby, the tool holder 1
5 is fastened by the tapered sleeve 21 with a strong force, and the tapered sleeve 21 is fastened with a strong force by the main shaft 10.
Are firmly held integrally with the main shaft 10.

As described above, when the processing machine operates to perform the processing, the spindle 10 rotates at a very high speed, and the spindle 10
The tapered hole 13 receives a force in the direction of increasing the diameter. When the diameter of the tapered hole 13 is increased by centrifugal force, in the tool holder 15 according to the present embodiment, the sleeve 21 and the elastic ring 23 which have been compressed are radially changed from the state where the diameter is reduced by the elastic force. Return, no gaps. In addition, the tapered sleeve 21 is moved in the direction of arrow A by the elastic force.

As a result, even if the diameter of the tapered hole 13 is increased, the tight contact between the main shaft 10 and the tapered sleeve 21 is maintained, and the strong integral connection between the main shaft 10 and the tool holder 15 is maintained. Become. For this reason, even if the ultrahigh-speed rotation is performed, the axis of the tool holder 15 does not shift, and high-precision machining can be performed.

The state shown in FIG. 3, that is, the tool holder body 16
The size of the gap 26 between the back end face 16a of the main body and the front end face 10a of the main body in a state where the ring 22 and the tapered sleeve 21 are in close contact with each other (a state in which no gap remains in the ring groove 21c) is determined by the following equation. When the tapered sleeve 21 is pushed into the tapered hole 13 so that the gap 26 becomes zero (the state shown in FIG. 4), the spindle 10 is an element related to the magnitude of the force for tightening the tool holder 15, and is important.

However, the size of the gap 26 varies depending on the processing machine to which the tool holder 15 is to be mounted, due to individual differences due to differences in manufacturers and the like. However, in the tool holder 15 according to the present embodiment,
This individual difference on the processing machine side can be easily absorbed by changing the thickness of the metal ring 22, and there is an advantage that the size of the gap 26 can be made a desired size.

FIG. 5 is a view showing another embodiment of the tapered sleeve 21. FIG. 5 (b) is a view of the inside of the tapered sleeve viewed from the opening side of the medium-diameter hole, and FIG. FIG. 3 is a view taken along line aa of FIG. In the tapered sleeve according to this embodiment, six grooves 21d are equally formed in the circumferential direction on the surfaces of the medium diameter hole and the small diameter hole on the inner peripheral surface. In the embodiment shown in FIG.
1, the entire inner peripheral surface is in close contact with the shaft body 17 of the tool holder 15, but in this embodiment, the groove 21d is in a non-contact state with the shaft body 17 and is shown in a satin shape. The portion 21e comes into contact. Therefore, when the tool holder 15 is mounted on the main shaft 10 and the diameter of the tapered sleeve 21 is reduced,
Due to the presence of the groove 21d, the shrinkage in the radial direction is increased, and the shaft 17 can be more firmly tightened.

FIG. 6 is a view showing still another embodiment of the tapered sleeve. FIG. 6B is a view of the inside of the tapered sleeve as viewed from the opening side of the medium-diameter hole, and FIG. FIG. 3 is a view taken along line aa of FIG. In this embodiment,
The portion 21e shown in the shape of a pear-like land comes into contact. Groove 21d
Are narrowed to form eight grooves. Whether to provide a wide groove as shown in FIG. 5 or a large number of narrow grooves as shown in FIG. 6 is determined in consideration of the material and size of the tapered sleeve, the angle of the taper, and the like.

In the embodiment shown in FIG. 1, the shaft 17 has a two-stage structure of a middle diameter portion and a small diameter portion. However, it goes without saying that the entire shaft 17 may be a single diameter shaft. But,
In this case, it is necessary to change the attachment position of the elastic ring. FIG. 7 is a diagram showing the embodiment. In this embodiment, the tool holder body 16 of the tapered sleeve 31 is used.
A ring groove 31a is engraved on the inner peripheral portion of the side end surface, and an elastic ring 32 having a rectangular cross section is housed in the ring groove 31a.
A metal ring 33 having an L-shaped cross section is housed at a position where the elastic ring 32 is compressed.

In the state where the gap 26 shown in FIG. 3 exists,
A gap 34 is formed between the metal ring 33 and the tapered sleeve 31 in FIG. 7 by the elastic force of the elastic ring 32, and when the gap 26 is eliminated, the metal ring is opposed to the elastic force of the elastic ring 32. 33 presses and compresses the elastic ring 32 to contact the tapered sleeve 31, and the gap 34 is eliminated. Thereby, the same operation and effect as those of the elastic ring and the metal ring of the embodiment shown in FIG. 1 can be obtained.

[0028]

According to the present invention, it is not necessary to perform high-precision uniform processing, so that the manufacturing cost is reduced, and the main shaft and the center of the shaft are always aligned without being affected by centrifugal force even during processing. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram of a tool holder according to an embodiment of the present invention.

FIG. 2 is a view in which the tool holder shown in FIG. 1 is inserted into a main shaft.

FIG. 3 is a drawing in which the tool holder shown in FIG. 2 is drawn into a main shaft.

FIG. 4 is a view showing a state where the tool holder shown in FIG. 3 has been further pulled into the spindle and the mounting is completed.

FIG. 5 is a diagram showing an inner surface side of another embodiment of the tapered sleeve.

FIG. 6 is a diagram showing an inner surface side of still another embodiment of the tapered sleeve.

FIG. 7 is a configuration diagram showing another embodiment of the elastic ring attachment portion of the tapered sleeve.

FIG. 8 is a diagram showing a conventional tool holder mounting structure.

[Explanation of symbols]

 Reference Signs List 10 Main shaft 12 Puller 13 Taper hole 15 Tool holder 16 Tool holder main body 16a Main body back end face 17 Shaft 17a Medium diameter part 17b Small diameter part 20 Pull stud 21 Tapered sleeve 22 Metal ring 23 Elastic ring

Claims (4)

[Claims] 1. A tool holder which is exchangeably mounted in a tapered hole formed in a main shaft of a processing machine, wherein a shaft body protruding from a back of a main body to which a tool is mounted and an outer surface are formed in the tapered hole. A tapered sleeve which is formed in a conical shape and whose inner peripheral surface is fitted to the shaft body, and which is fitted to the shaft body and the tapered sleeve is fitted to the shaft body and inserted into the tapered hole. A tool holder comprising: an elastic ring that is compressed against an elastic force in an axial direction and biases the tapered sleeve toward the tapered hole. 2. The tool holder according to claim 1, wherein a plurality of concave grooves extending in the axial direction are uniformly provided in the inner peripheral surface of the tapered sleeve in the circumferential direction. 3. The device according to claim 1, wherein a slight gap is formed between the main shaft side end surface of the main body and the main shaft front end surface in a state where the tapered sleeve is in contact with the tapered hole. The tool holder is characterized in that the tapered sleeve is further inserted into the tapered hole so that the mounting is completed, so that the spindle-side end surface and the spindle front-end surface are brought into close contact with each other so as to become zero. 4. The shaft body according to claim 3, wherein a ring groove is formed in the inner peripheral portion of the opening of the tapered sleeve on the main body side, and the rigid ring having a thickness greater than an axial depth of the ring groove is provided. A tool holder, wherein the dimension of the gap is adjusted according to the thickness of the rigid ring.