JP6276642B2 - Tool holding device for machine tools - Google Patents

Description

  The present invention relates to a tool holding device for holding a cutting tool such as an end mill in a machine tool such as a machining center. is there.

  Conventionally, in a machine tool such as a machining center, for example, a cutting tool is attached to a main shaft via a tool holding device, and one end side of the main shaft is brought into contact with a workpiece while the cutting tool is rotated around the rotation axis by the rotation of the main shaft. Cutting is performed.

  When cutting, the cause of deterioration of the processing accuracy of the processing target is chatter vibration of the cutting tool accompanying the processing. For example, when an end mill with a relatively long length is used to adapt to the workpiece shape, etc., the amount of protrusion from the tool holding device is large, so that the tool tip side is easy to swing, and the tool's axial runout becomes chatter. Vibration occurred, causing a reduction in machining accuracy. In order to ensure the processing accuracy, the processing load must be reduced by reducing the processing speed, and the processing efficiency is deteriorated.

In order to solve such a problem, a vibration isolating member having rubber elasticity or viscoelasticity is attached to the outer peripheral side of the cutting tool, and the vibration isolating member is adapted to follow the bending or twisting of the cutting tool during cutting. A modification has been proposed in which chatter vibration of a cutting tool is attenuated by a damping effect of a vibration isolating member (see, for example, Patent Document 1).
In addition, the first vibration isolating member and the second vibration isolating member are mounted on the outer peripheral side of the tool holder main body to form a double ring structure between the cutting tool and the first vibration isolating member. Two O-rings and two O-rings are incorporated between the first and second anti-vibration members respectively, and the chatter vibration of the cutting tool during cutting with a total of four O-rings. There is also proposed one that attenuates (see, for example, Patent Document 2).

International Publication No. 2013/011944 International Publication No. 2011-067828

However, in the thing of patent document 1, the vibration isolating member must be mounted | worn with each of the cutting tool to be used, and the number of the prevention members required for mounting | wearing is so that there are many cutting tools to be used. There is a problem that the cost increases due to the increase.
Moreover, in the thing of patent document 2, in order to give the vibration isolating function to the tool holding device side, although the problem of the said patent document 1 can be solved since it has a vibration isolating function on the tool holding device side, The vibration isolating member to be mounted on the tool holder main body has a double ring structure, and a total of four O-rings must be incorporated therein, resulting in a complicated structure.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a tool holding device for a machine tool that can suppress chatter vibration of a cutting tool with a simple structure. .

In order to achieve the above object, a machine tool tool holding device according to the present invention comprises:
Comprising a holder for being rotated around the rotational axis by contacting the distal side workpiece holding a cutting tool for cutting in, the holder, to form a free vibratable variable vibration unit, the cutting during cutting of the workpiece tool so as to vibrate its variable oscillation unit with the vibrating, and a machine tool of the tool holding device in which the vibration of the movable vibration part as attenuated by viscoelastic body,
The holder is made provided with a chuck cylinder portion having a base end side of the cutting tool or collet is inserted, the end of the previous SL chuck cylinder portion, a pair of which are cut along the rotational axis direction at intervals in the circumferential direction By providing the slit, the vibrating portion and a chuck claw portion for gripping a cutting tool or a collet disposed between the vibrating portions adjacent in the circumferential direction are formed,
The cutting tool or collet inserted into the chuck tube part and the oscillating part itself are not in contact with each other, and a gap is provided between them, and the viscoelastic body is disposed in the gap. It is.

  According to the tool holding device of the machine tool of the present invention, the vibration part formed in the holder is vibrated with the occurrence of chatter vibration of the cutting tool, and the vibration of the vibration part is attenuated by the viscoelastic body. The vibration of the other oscillating part that tends to vibrate is attenuated, so that the vibration of the other cutting tool that easily vibrates is damped (vibration mode damping theory), and chatter vibration of the cutting tool can be suppressed. . Moreover, such a function and effect can be obtained with a simple structure in which a oscillating portion is formed in the holder and the vibration of the oscillating portion is attenuated by a viscoelastic body.

Further, in the present invention, since the oscillating portion is formed by providing a slit in the chuck cylinder portion, there is an advantage that the oscillating portion can be easily formed. Furthermore, since the viscoelastic body is arranged in the gap provided between the cutting tool or collet and the vibrated portion, the inner peripheral surface of the chuck claw portion and the inner peripheral surface of the viscoelastic body are flush with each other. In addition, the cutting tool or the collet can be smoothly inserted and securely held.

1 is an overall perspective view of a tool holding device according to a first embodiment of the present invention. It is the sectional view on the AA line of FIG. It is a whole perspective view of the tool holding device concerning a 2nd embodiment of the present invention. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a figure which shows the tool holding apparatus which concerns on the 3rd Embodiment of this invention, (a) is a whole perspective view, (b) is a disassembled perspective view. It is CC sectional view taken on the line of FIG.

  Next, a specific embodiment of a tool holding device for a machine tool according to the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is an overall perspective view of the tool holding device according to the first embodiment of the present invention. 2 shows a cross-sectional view taken along line AA of FIG.

<General description of the tool holding device>
A tool holding device 1A shown in FIG. 1 is attached to a spindle of a machine tool (not shown) such as a machining center, for example. A holder 3 for holding the cutting tool 2 is provided.

<Description of holder>
The holder 3 has a cylindrical body portion 3a formed with a ring-shaped groove 4 with which a tool changing arm of an ATC (automatic tool changer) (not shown) provided in the machine tool is engaged. A tapered taper shank portion 3b that is inserted and connected to the main spindle of the machine tool is integrally extended on the proximal end side of the portion 3a, and the proximal end side of the cutting tool 2 is located on the distal end side of the barrel portion 3a. The chuck cylinder portion 3c to be inserted is integrally extended.

<Description of chuck cylinder>
The chuck cylinder 3c has a thick cylindrical shape that tapers slightly toward the distal end side, and has a tool insertion port 5 into which the cutting tool 2 can be inserted toward the inside. Yes.

<Description of the vibration unit>
A vibrating portion 7 formed by providing a pair of slits 6 cut along the rotation axis Os direction at a predetermined interval in the circumferential direction at a portion from the intermediate position to the tip of the chuck cylinder portion 3c. Three are arranged at equiangular (120 °) intervals in the circumferential direction. Thus, by providing the pair of slits 6, it is possible to easily form the oscillating portion 7 in which the proximal end side is fixed and the distal end side can freely vibrate.

<Description of viscoelastic body>
As shown in FIG. 2, the cutting tool 2 inserted into the inside through the tool insertion port 5 and each oscillating portion 7 itself are not in contact with each other, and a gap t is provided between them. Is provided with a viscoelastic body 10, and the viscoelastic body 10 is attached to the oscillating portion 7 so as to be in contact with the cutting tool 2. Here, the viscoelastic body 10 has a spring element and a damping element, and has a non-linear spring constant. That is, when the viscoelastic body 10 is deformed by applying a load, the spring constant of the viscoelastic body 10 changes depending on the magnitude of the load. Examples of the viscoelastic body 10 include rubber.

  As shown in FIG. 1, a portion between the vibrating portions 7 adjacent in the circumferential direction in the chuck cylinder portion 3 c is a chuck claw portion 8, and the cutting tool 2 is gripped by a total of three chuck claw portions 8. Be able to. A cylindrical fastening body 9 is rotatably fitted on the outer peripheral side of the tip portion of the chuck cylinder portion 3c via a rolling element (not shown) (for example, a needle roller).

  When holding the cutting tool 2 in the tool holding device 1A, the clamping body 9 is rotated in one direction (clamping side) while the cutting tool 2 is inserted into the tool insertion slot 5, and tightened. The rolling element is rolled spirally between the two surfaces of the body 9 and the chuck cylinder portion 3c, and the rolling element is moved together with the fastening body 9 to the proximal end side of the chuck cylinder portion 3c. The tightening operation by the tightening body 9 generates a force for reducing the diameter of the chuck cylinder portion 3c, and the cutting tool 2 can be clamped and fixed by the three chuck claws 8. Note that the cutting tool 2 can be released from being fixed by the chuck claws 8 by rotating the tightening body 9 in the other direction.

In the tool holding device 1 </ b> A configured as described above, the cutting tool 2 inserted into the inside of the chuck cylinder portion 3 c through the tool insertion port 5 is moved into three chuck claws by the tightening operation of the tightening body 9. While being sandwiched and fixed by the portion 8, the vibration 7 is pressed through the viscoelastic body 10.
Then, by rotating the spindle of the machine tool, the cutting tool 2 is rotated about the rotation axis Os, and one end thereof is brought into contact with the workpiece to perform cutting.
At this time, when chatter vibration is generated due to a large axial runout of the cutting tool 2, the vibration section 7 of the chuck cylinder 3 c is vibrated, and the vibration of the vibration section 7 is attenuated by the viscoelastic body 10. Is done.

<Description of effects>
According to the tool holding device 1A of the first embodiment, the vibration of the other oscillating portion 7 that is likely to vibrate is attenuated, whereby the vibration of the other cutting tool 2 that is likely to vibrate is attenuated (vibration mode). Damping theory), chatter vibration of the cutting tool 2 can be suppressed. In addition, such an effect can be obtained with a simple structure in which the oscillating portion 7 is formed in the chuck cylinder portion 3 c of the holder 3 and the vibration of the oscillating portion 7 is attenuated by the viscoelastic body 10.

[Second Embodiment]
FIG. 3 is an overall perspective view of the tool holding device according to the second embodiment of the present invention. FIG. 4 is a cross-sectional view taken along line BB in FIG. In addition, in the tool holding device 1B of the second embodiment, the same or similar parts as those of the tool holding device 1A of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the following, a description will be made centering on the parts specific to the tool holding device 1B of the present embodiment (the same applies to the third embodiment described later).

In the tool holding device 1B shown in FIG. 3, the vibrating portion 7 provided in the first embodiment is not provided in the portion from the intermediate position to the tip of the chuck tube portion 3c, and the chuck tube portion A vibrating portion 7 formed by providing a pair of slits 6 cut along the rotation axis Os direction at a predetermined interval in the circumferential direction at a portion extending from the intermediate position of 3c to the rear end is provided in the circumferential direction. Three are arranged at equiangular (120 °) intervals.
As shown in FIG. 4, the cutting tool 2 inserted into the inside through the tool insertion port 5 and each oscillating portion 7 itself are not in contact with each other, and a gap t is provided between them. Is provided with a viscoelastic body 10, and the viscoelastic body 10 is attached to the oscillating portion 7 so as to be in contact with the cutting tool 2.

  Further, in the tool holding device 1B, the chuck claw portion 8 provided in the tool holding device 1A of the first embodiment is not provided, and the chuck cylinder portion 3c is moved by the tightening operation by the tightening body 9. The cutting tool 2 is clamped and fixed by reducing the diameter by elastic deformation.

<Description of effects>
Also with the tool holding device 1B configured as described above, when the vibration of the axial center of the cutting tool 2 is increased and chatter vibration is generated during the cutting process, the vibrationable portion 7 of the chuck tube portion 3c is caused accordingly. Since the vibration is vibrated and the vibration of the vibrable portion 7 is attenuated by the viscoelastic body 10, the same effect as the tool holding device 1A of the first embodiment can be obtained.

[Third Embodiment]
FIG. 5 is a view showing a tool holding device according to a third embodiment of the present invention, and shows an overall perspective view (a) and an exploded perspective view (b), respectively. FIG. 6 shows a cross-sectional view taken along line CC of FIG.

  In the tool holding device 1 </ b> C shown in FIGS. 5A and 5B, the proximal end side of the cutting tool 2 is inserted into the chuck cylinder portion 3 c of the holder 3 via the collet 11.

<Description of chuck cylinder>
As shown in FIG. 5B, the chuck cylinder portion 3c has a thick cylindrical shape, a large-diameter cylinder portion 12 having a predetermined outer diameter from the proximal end to the vicinity of the distal end portion, and a distal end from the vicinity of the distal end portion. And a small-diameter cylindrical portion 13 having a smaller diameter than the large-diameter cylindrical portion 12 and having an external thread on the outer peripheral surface, and a collet insertion port 14 into which the collet 11 can be inserted inward is provided at the center. doing.
A tapered surface 15 is formed on the inner peripheral side of the collet insertion port 14 so that the inner diameter becomes smaller as it proceeds from the distal end side to the proximal end side of the chuck cylinder portion 3c.

<Description of the vibration unit>
In a portion extending from the intermediate position to the tip of the chuck cylinder portion 3c, a vibrating portion 17 formed by providing a pair of slits 16 cut along the rotation axis Os direction at a predetermined interval in the circumferential direction, Three are arranged at equiangular (120 °) intervals in the circumferential direction. Thus, by providing the pair of slits 16, it is possible to easily form the oscillating portion 17 in which the proximal end side is fixed and the distal end side can freely vibrate.

<Description of viscoelastic body>
As shown in FIG. 6, the collet 11 inserted into the collet insertion port 14 and each oscillating portion 17 itself are not in contact with each other, and a gap t is provided between them. A viscoelastic body 20 similar to the viscoelastic body 10 is disposed, and the viscoelastic body 20 is attached to the oscillating portion 17 so as to be in contact with the cutting tool 2.

  As shown in FIG. 5 (b), in the chuck cylinder portion 3 c, a portion between the vibrating portions 17 adjacent in the circumferential direction is a chuck claw portion 18, and the collet 11 is composed of a total of three chuck claw portions 18. Can be grabbed.

  The collet 11 is formed into a thick cylindrical shape having a tapered surface 19 on the outer peripheral side that engages with the tapered surface 15 of the collet insertion port 14 in the chuck tube portion 3c, and the cutting tool 2 is disposed inside the central portion. Has a tool insertion port 21 that can be inserted in a penetrating state.

  As shown in FIG. 6, a cylindrical tightening body 25 is attached to the tip of the collet 11 in a state in which the concave and convex portions are engaged with each other to prevent the collet 11 from coming off. The tightening body 25 can be screwed into the small diameter cylindrical portion 13.

  When the cutting tool 2 is held in the tool holding device 1C, the collet 11 in the state in which the cutting tool 2 is inserted is inserted into the collet insertion port 14 of the chuck cylinder portion 3c, and the tightening body 25 has a small diameter. The tube portion 13 is screwed and a tightening operation by the tightening body 25 is performed. Thereby, a force for reducing the diameter of the small diameter cylindrical portion 13 of the chuck cylindrical portion 3c is generated, and the cutting tool 2 can be sandwiched and fixed by the three chuck claws 18 via the collet 11. Note that, by performing an operation of loosening the tightening body 25, the fixing of the cutting tool 2 via the collet 11 by the chuck claws 18 can be released.

<Description of effects>
In the tool holding device 1C configured as described above, when the cutting tool 2 is rotated around the rotation axis Os and one end side thereof is brought into contact with the workpiece to perform cutting, the axis of the cutting tool 2 is obtained. When the vibration becomes large and chatter vibration is generated, the chatter vibration is transmitted to the oscillating portion 17 of the chuck tube portion 3c via the collet 11 to vibrate the oscillating portion 17, and the vibration of the oscillating portion 17 is viscoelastic. It is attenuated by the body 20. Therefore, the same effect as the tool holding device 1A of the first embodiment can be obtained.

  As mentioned above, although the tool holding device of the machine tool of this invention was demonstrated based on several embodiment, this invention is not limited to the structure described in the said embodiment, The structure described in each embodiment is used. The configuration can be changed as appropriate within a range that does not depart from the spirit of the invention, such as appropriate combination.

  The machine tool holding device of the present invention has a simple structure and can suppress chatter vibration of a cutting tool, and therefore holds a rotary cutting tool such as an end mill in a machine tool such as a machining center. It can be suitably used for the purpose of

1A, 1B, 1C Tool holding device 2 Cutting tool 3 Holder 3c Chuck cylinder part 6, 16 Slit 7, 17 Vibrating part 10, 20 Viscoelastic body

Claims (1)

Comprising a holder for being rotated around the rotational axis by contacting the distal side workpiece holding a cutting tool for cutting in, the holder, to form a free vibratable variable vibration unit, the cutting during cutting of the workpiece tool so as to vibrate its variable oscillation unit with the vibrating, and a machine tool of the tool holding device in which the vibration of the movable vibration part as attenuated by viscoelastic body,
The holder is made provided with a chuck cylinder portion having a base end side of the cutting tool or collet is inserted, the end of the previous SL chuck cylinder portion, a pair of which are cut along the rotational axis direction at intervals in the circumferential direction By providing the slit, the vibrating portion and a chuck claw portion for gripping a cutting tool or a collet disposed between the vibrating portions adjacent in the circumferential direction are formed,
A cutting tool or collet inserted into the chuck cylinder and the oscillating part itself are not in contact with each other, and a gap is provided between them, and the viscoelastic body is disposed in the gap. Machine tool holding device.

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