JPH11235611A - Spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle device with high rigidity sufficient for holding a tool holder, without the need for strict control of a space between an end surface of a spindle shaft and an end surface of a flange part of the tool holder. SOLUTION: A nut 32 is screwed to an end of a spindle shaft 12. A pull stud 23 of a tool holder 20 is clamped by a draw bar 14. The nut 32 is then tightened, thereby making a taper shank part 22 come in close contact with a tapered hole 13, and making an end surface 32a of the but 32 come in close contact with an end surface 21a of a flange part 21 of a tool holder 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device capable of obtaining a sufficiently high rigidity for holding a tool holder without requiring strict management of a gap between an end surface of a spindle shaft and an end surface of a flange portion of a tool holder. .

[0002]

2. Description of the Related Art In a machine tool such as a machining center (MC) provided with an automatic tool changer (ATC), a tapered hole 2 for tool attachment is formed at the tip of a spindle shaft 1 as shown in FIG. A predetermined tool is mounted by fitting the tapered shank portion 4 of the tool holder 3 into the tapered hole 2.

There are two types of such taper shank portions 4, a BT type having a long taper defined by JIS standards and a short taper type defined by DIN standards. The tapered shank portion 4 shown in FIG. 3 is an example of a BT type, and the tool holder 3 is held in the tapered hole 2 of the spindle shaft 1 only at the tapered shank portion 4. When the tool holder 3 is brought into contact with the tapered hole 2, the entire surfaces of the tool holder 3 do not accurately contact, and a sufficiently high rigidity for holding the tool holder 3 cannot be obtained, and heavy cutting is difficult.

[0004] From this, as shown in FIG.
Insert the tapered shank 4 of the tool holder 3 into the spindle 1
When the tool holder 3 is mounted on the spindle shaft 3, the end surface 5 a of the flange portion 5 of the tool holder 3 abuts on the end surface 1 a of the spindle shaft 1. , The tool holder 3 is held by the two-sided constraint of the constraint by the taper and the constraint by the end face,
Sufficiently high rigidity is obtained for holding the tool holder 3.

In Japanese Patent Application Laid-Open No. 7-178607, a sleeve is provided on the outer periphery of the end of the spindle shaft, and hydraulic pressure is applied between the inner peripheral surface of the sleeve and the outer peripheral surface of the end of the spindle shaft. This sleeve is brought into contact with the end face of the tool holder, then the oil pressure is removed, the sleeve is fixed to the spindle shaft, and the tool holder is held on the spindle shaft,
Thus, a configuration is disclosed in which a sufficiently high rigidity is obtained for holding the tool holder.

[0006]

As described above, FIG.
When the tool holder 3 is held by the two-sided constraint shown in FIG.
It is generally difficult to make the end surface 5a of the flange portion 5 of the tool holder 3 come into contact with the end surface 1a of the spindle shaft 1 at the same time when the taper shank portion 4 comes into contact with the tapered hole 2. Thus, the gap between the end face 5a of the flange portion 5 and the end face 1a of the spindle shaft 1 is set to a minus value to apply the preload.

However, since this gap is about 2 μm and needs to be kept within an extremely severe range, the dimension of the taper in and out of the end face 1a of the spindle shaft 1 and the dimensional accuracy from the clamp portion to the end face 1a of the spindle shaft are reduced. You have to manage it strictly,
Conventionally, there is a problem that machining of a spindle shaft is difficult and machining must be performed with high accuracy.

In the configuration disclosed in Japanese Patent Laid-Open No. 7-178607, a sleeve must be provided on the outer periphery of the end of the spindle shaft, and a hydraulic mechanism must be used.
There is a problem that the configuration is complicated and complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and it is not necessary to strictly manage a gap between an end surface of a spindle shaft and an end surface of a flange portion of a tool holder. An object of the present invention is to provide a spindle device capable of obtaining sufficiently high rigidity.

[0010]

In order to achieve the above object,
In the spindle device according to the present invention, a taper shank portion of a tool holder is inserted into a taper hole formed in a spindle shaft, and a clamped portion of the tool holder is clamped by a clamp mechanism in the spindle shaft, so that the tool holder is In a spindle device fixed to a spindle shaft, a nut is provided at an end of the spindle shaft or a flange portion of a tool holder, and after clamping the clamped portion of the tool holder by the clamping mechanism, the nut is tightened. Thereby, the taper shank is brought into close contact with the taper hole, and the end surface of the nut is brought into close contact with the end surface of the flange portion of the tool holder or the end surface of the spindle shaft.

As described above, according to the present invention, a nut is provided at the end of the spindle shaft or the like, and after the tool holder is clamped by the clamp mechanism, the nut is tightened, thereby forming the tapered shank portion into the tapered hole. And the end face of the nut is brought into close contact with the end face of the flange portion of the tool holder. Therefore, it is not necessary to strictly manage the gap between the end face of the spindle shaft and the end face of the flange part of the tool holder, and the tool holder is held by the two-sided constraint of the taper constraint and the constraint by the end face while having a simple configuration. And a sufficiently high rigidity can be obtained with respect to the holding of the tool holder.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A spindle device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a main part of a spindle device according to a first embodiment of the present invention. In a BT type spindle device having a long taper defined by JIS standards, a housing 11 includes a bearing 11
, The spindle shaft 12 is rotatably supported, and is rotated by a drive mechanism (not shown). A tapered hole 13 is formed inside the spindle shaft 12, and a drawbar 14 that moves forward and backward is provided on the back side of the tapered hole 13. The drawbar 14 has a pull stud of a tool holder 20 described later. Ball 15 for engaging pulley 23 with head 23
Is provided.

The tool holder 20 is provided with a flange portion 21 having a large diameter and a taper shank portion 22 which fits into the taper hole 13 of the spindle shaft 12. At the tip of the tapered shank portion 22, a pull stud 23 for clamping the ball 15 is provided. When the pull stud 23 of the tool holder 20 is clamped by the ball 15 and the draw bar 14 is retracted, the tapered shank portion 22 of the tool holder 20 comes into contact with the tapered hole 13 of the spindle 12. I have.

In the first embodiment, a male screw portion 31 is formed on the outer peripheral surface of the end portion of the spindle shaft 12, and a nut 32 and a nut 33 are screwed to the male screw portion 31. .

The nut 32 is tightened after the pull stud 23 of the tool holder 20 is clamped by the draw bar 14 and the ball 15. This allows
At the same time that the tapered shank portion 22 is in close contact with the tapered hole 13, the end face 32 a of the nut 32 is
To the end surface 21a of the flange portion 21. At this time, the nut 33 is also tightened and pressed against the nut 32, and the double nut prevents the nut from being loosened.

As described above, in the first embodiment, by tightening the nuts 32 and 33, the tapered shank portion 22 is brought into close contact with the tapered hole 13, and at the same time, the end surface 32a of the nut 32 is fixed to the flange portion of the tool holder 20. End face 21 of 21
a, it realizes a two-sided constraint of a constraint by a taper and a constraint by an end face while having a simple configuration,
The tool holder 20 can be held by this two-sided constraint, and sufficiently high rigidity can be obtained for holding the tool holder 20. Further, as in the prior art, the end face 12a of the spindle shaft 12 and the flange 21
It is not necessary to perform strict management of the gap with the end face 21a,
There is no need to perform high-precision processing.

FIG. 2 is a longitudinal sectional view of a main part of a spindle device according to a second embodiment of the present invention. The spindle device is a BT type having a long taper defined by JIS standards. The same members as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In the second embodiment, a male screw portion 31 is formed on the outer peripheral surface of a flange portion 21 having a small diameter, and a nut 32 and a nut 33 are screwed and provided on the male screw portion 31. I have.

The nut 32 is connected to the pull stud 23 of the tool holder 20 by the draw bar 14 and the ball 15.
Is clamped and then tightened, whereby the tapered shank portion 22 is brought into close contact with the tapered hole 13 and
The end surface 32 a of the nut 32 is in close contact with the end surface 12 a of the spindle 12. Also, at this time, similarly to the first embodiment, the nut 33 is also tightened and pressed against the nut 32, and the double nut prevents the nut from being loosened.

As described above, in the second embodiment, by tightening the nuts 32 and 33, the tapered shank portion 22 is brought into close contact with the tapered hole 13, and at the same time, the end surface 32a of the nut 32 is moved to the end surface 12a of the spindle shaft 12. As in the first embodiment, the tool holder 20 is held by the two-sided constraint, with the simple configuration, but with the taper and the end surface. Therefore, a sufficiently high rigidity can be obtained with respect to the holding of the tool holder 20. Further, similarly to the first embodiment, there is no need to strictly manage the gap between the end surface 12a of the spindle shaft 12 and the end surface 21a of the flange portion 21 of the tool holder 20, and it is not necessary to perform high-precision machining.

The present invention is not limited to the above-described embodiment, but can be variously modified.

[0023]

As described above, according to the present invention, a nut is provided at the end of the spindle shaft or the like, and after the tool holder is clamped by the clamp mechanism, the nut is tightened, thereby forming a taper. The shank portion is brought into close contact with the tapered hole, and the end surface of the nut is brought into close contact with the end surface of the flange portion of the tool holder. Therefore, it is not necessary to strictly manage the gap between the end face of the spindle shaft and the end face of the flange part of the tool holder, and the tool holder is held by the two-sided constraint of the taper constraint and the constraint by the end face while having a simple configuration. And a sufficiently high rigidity can be obtained with respect to the holding of the tool holder.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a spindle device according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a spindle device according to a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a part of a conventional spindle device.

FIG. 4 is a longitudinal sectional view showing a part of a conventional two-surface constrained spindle device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Housing 11 Bearing 12 Spindle shaft 13 Taper hole 14 Drawbar (clamp mechanism) 15 Ball (clamp mechanism) 20 Tool holder 21 Flange part 22 Taper shank part 23 Pull stud (clamped part) 31 Male thread part 32 Nut 33 Nut

Claims (1)

[Claims] 1. A taper shank portion of a tool holder is inserted into a taper hole formed in a spindle shaft, and a clamped portion of the tool holder is clamped by a clamp mechanism in the spindle shaft, so that the tool holder is connected to the spindle shaft. In the spindle device to be fixed, a nut is provided at an end of the spindle shaft or a flange portion of the tool holder, and after clamping the clamped portion of the tool holder by the clamping mechanism, the nut is tightened. A spindle device, wherein the taper shank portion is brought into close contact with the tapered hole, and an end surface of the nut is brought into close contact with an end surface of a flange portion of the tool holder or an end surface of a spindle shaft.