JPH1199403A - Spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To repair only a broken spindle if its part is broken by processing a spindle inner hole with a general-purpose machine tool with high precision. SOLUTION: A spindle 3 which is rotatably-supported by front bearings 4a, 4b, 4c and a rear bearing 5 inside a spindle housing and whose rotation is driven by a built-in motor 16 is divided into two: a front shaft 3a and a rear shaft 3b. Between the front bearings 4a, 4b, 4c and the rear bearing 5, the rear end of the front shaft 3a and the front end of the rear shaft 3b are male-to-female connected for integral formation. The male-to-female connected part is formed at a position overlapped or not overlapped with the position where the built-in motor 16 is installed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle device for a machine tool such as a machining center or an NC machine.

[0002]

2. Description of the Related Art As shown in FIG. 5, a spindle device in a machine tool such as a machining center or an NC dedicated machine has a front spindle housing 1a and a front spindle housing 1a.
And a rear spindle housing 1b connected to the rear end of the rear bearing housing 2 via a rear bearing housing 2.
b, 4c and a bearing surface 20 formed on a sleeve 17 which is rotatably supported on the rear bearing housing 2 by a rear bearing 5 held by a bearing retainer 6 and a cap 7 and fitted on the main shaft 3. Rotor 16
b, and the stator 1 is attached to the front spindle housing 1a.
The main shaft 3 is driven to rotate by a built-in motor 16 having the fixed 6a. Note that reference numeral 8 in the drawing denotes a hydrostatic bearing.

The spindle 3 has a tool holder 1 at its tip.
0 is provided, and the main shaft inner hole 1 is provided.
3, a collet chuck 12 for clamping and unclamping a pull stat 11 of a tool holder 10 mounted on the tapered hole 9, a draw bar 15 associated with the collet chuck 12, and a mechanism for operating the collet chuck 12 in a clamping direction. In this configuration, a disc spring 14 for drawing in the draw bar 15 is inserted. In order to operate the collet chuck 12 in the unclamping direction, the draw bar 1 is used.
5 is coupled with an unillustrated unclamping cylinder during operation.

[0004]

In the above-described conventional spindle device, the spindle 3 tends to be elongated by increasing the speed of the spindle 3 and incorporating the built-in motor 16, and the spindle inner hole 13 formed in the spindle 3 has a problem. It is required to machine deeply with high precision, but it is difficult to machine such deep holes with high precision. It is conceivable to use a dedicated processing machine, but the cost is high and the efficiency is low.

If the machining accuracy of the spindle bore 13 is poor, the disc spring 1
When the spindle 4 is incorporated, the center of gravity of the main shaft 3 and the center of gravity of the disc spring 14 are displaced, and the main shaft 3 is unbalanced when rotated. In addition, it affects the processing accuracy. Furthermore, even when a part of the main shaft 3 (for example, a built-in motor) is damaged, there is a problem that the whole main shaft has to be replaced, which is wasteful.

SUMMARY OF THE INVENTION An object of the present invention is to enable machining of a spindle bore with a general-purpose machine tool with high precision, and to repair a damaged part of the spindle by replacing only the damaged part of the spindle. It was done.

[0007]

According to a first aspect of the present invention, a draw bar is drawn in by a disc spring inserted in a shaft inner hole, and a tool is drawn by a collet chuck. A main shaft equipped with a tool clamping device for clamping the main shaft is rotatably supported by a front bearing and a rear bearing in a main shaft housing, and the main shaft is rotated by a built-in motor. And a rear end of the front shaft and a front end of the rear shaft are integrally formed between the front bearing and the rear bearing.

According to a second aspect of the present invention, the front shaft and the rear shaft of the main shaft are coupled at a position overlapping with a position where the built-in motor of the main shaft is mounted. is there.

Further, in the above structure, the front shaft and the rear shaft of the main shaft are coupled at a position not overlapping with a position where the built-in motor of the main shaft is mounted. It is.

In the above construction, the rear end of the main shaft may be a male part, and the front end of the rear shaft may be integrally formed as a female part, and an outer periphery of a front end of the rear shaft may be formed. Wherein the built-in motor is fixed to the motor.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention. 1 and 2, the main spindle housing includes a front main spindle housing 1a and a rear main spindle housing 1b connected to a rear end of the front main spindle housing 1a via a rear bearing housing 2.

Reference numeral 3 denotes a main shaft. The main shaft 3 is a front shaft 3a.
And a rear shaft 3b. The front shaft 3a is provided with a front bearing 4 in a front spindle housing 1a.
a, 4b, 4c rotatably supported by the rear shaft 3b
Is rotatably supported by a rear bearing 5 held by a rear bearing housing 6 by a bearing retainer 6 and a cap 7.

The front shaft 3a and the rear shaft 3b are integrated between the front bearings 4a, 4b, 4c and the rear bearing 5 by connecting the rear end of the front shaft 3a and the front end of the rear shaft 3b together. Is formed. Incidentally, reference numeral 8 in the figure
Indicates a hydrostatic bearing.

A tapered hole 9 for mounting a tool holder 10 is provided at an end of a front shaft 3a of the main shaft 3, and a pull-stat 11 of the tool holder 10 mounted on the tapered hole 9 is clamped in a main shaft inner hole 13. A collet chuck 12 to be unclamped, a draw bar 15 associated with the collet chuck 12, and a disc spring 14 for retracting the draw bar 15 to operate the collet chuck 12 in the clamping direction are inserted and provided. Collet chuck 1
2 to operate the draw bar 15 in the unclamping direction.
Is coupled with an unclamping cylinder (not shown) during operation.

In the first embodiment, the rear end of the front shaft 3a is the male portion 3c, and the front end of the rear shaft 3b is the female portion 3d, which are integrated by shrink fitting. In this case, since the female portion 3d is on the outside, a seating surface 20 for fixing the rotor 16b of the built-in motor 16 is formed on the outer periphery of the female portion 3d, the rotor 16b is fixed thereto, and the stator 16a is placed in the front main shaft housing 1a. It is fixed.

A pocket 1 is provided on the fitting surface between the male portion 3c at the rear end of the front shaft 3a and the female portion 3d at the front end of the rear shaft 3b.
A hydraulic pressure introducing hole 19 communicating with the pocket 18 is provided, hydraulic pressure is supplied to the pocket 18 from a hydraulic supply device (not shown), and the male and female coupling is released by hydraulic pressure.

The overlapping portion of the male portion 3c and the female portion 3d is equal to or longer than the entire length of the built-in motor 16, but in the case of the built-in motor 16 having a small output, it may be about half of the entire length.

FIG. 3 shows a second embodiment of the present invention. In the second embodiment, the rear end of the front shaft 3a is a female portion 3d, and the front end of the rear shaft 3b is a male portion 3c. In this case, since the female part 3d at the rear end of the front shaft 3a is located outside, a seating surface 20 for fixing the rotor 16b of the built-in motor 16 is formed on the outer periphery of the female part 3d, and the rotor 16b is fixed to this. The stator 16a is fixed inside the front spindle housing 1a. Other configurations are the same as those of the first embodiment.

In the second embodiment, the overlapping portion of the male portion 3c and the female portion 3d is equal to or longer than the entire length of the built-in motor 16, but in the case of the built-in motor 16 having a small output, the entire length is reduced. It may be about half.

FIG. 4 shows a third embodiment of the present invention. In the third embodiment, the rear end of the front shaft 3a is a female portion 3d, and the front end of the rear shaft 3b is a male portion 3c, which is integrated by shrink fitting. In this case, male part 3
The length c is increased, the female portion 3d is shortened, and the overlapping portion of the male portion 3c and the female portion 3d is configured to be male and female at a position not overlapping the mounting position of the built-in motor 16.

In this case, the rotor 1 of the built-in motor 16
6b, a sleeve 17 is fitted to the male portion 3c at the front end of the rear shaft 3b, fixed to a seating surface 20 formed on the sleeve 17, and a stator 16a is fixed in the front main shaft housing 1a. Other configurations are the same as those of the first embodiment.

In any of the first to third embodiments, the main shaft 3 is divided into two parts, the front shaft 3a and the rear shaft 3b. It can be machined with high precision.

When the built-in motor 16 having a different size depending on the output is mounted, the built-in motor 16
It is sufficient to change the rear shaft 3b according to the size of, and the other components can be shared and standardized, so that the cost can be reduced.

Further, when a part of the main shaft 3 is broken,
It is only necessary to replace the front shaft 3a or the rear shaft 3b, and there is no need to replace the entire main shaft.

When the male / female connection is released when replacing the front shaft 3a or the rear shaft 3b, the rear main shaft housing 1
b, the cap 7, the rear bearing housing 2, the bearing retainer 6, and the rear bearing 5 are removed in that order, and then the hydraulic pressure is supplied to the pocket 18, whereby the male and female connection can be easily released by hydraulic pressure.

[0026]

As described above, according to the present invention, the main shaft has two front and rear structures, and the two main shafts are integrated by male and female connections, so that the deep inner hole of the main shaft can be machined with a general-purpose machine tool with high precision. It is possible to change the rear shaft according to the size of the built-in motor, and other components can be shared and standardized, so that costs can be reduced and part of the main shaft is damaged In this case, there is no need to change the exchange range, so that there is an economic effect.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of the apparatus of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the first embodiment.

FIG. 3 is an enlarged sectional view of a main part of a second embodiment of the apparatus of the present invention.

FIG. 4 is an enlarged sectional view of a main part of a third embodiment of the apparatus of the present invention.

FIG. 5 is a sectional view of a conventional device.

[Explanation of symbols]

 1a Front main shaft housing 1b Rear main shaft housing 2 Rear bearing housing 3 Main shaft 3a Front shaft 3b Rear shaft 3c Male portion 3d Female portion 4a Front bearing 4b Front bearing 4c Front bearing 5 Rear bearing 10 Tool holder 12 Collet chuck 13 Main shaft inner hole 14 Belleville spring 15 Drawbar 16 Built-in motor 18 Pocket

Claims (4)

[Claims] 1. A spindle having a tool clamping device for pulling a draw bar by a disc spring inserted into a spindle bore and clamping a tool by a collet chuck is rotatably supported in a spindle housing by a front bearing and a rear bearing. A spindle device rotatably driven by a built-in motor, wherein the spindle is divided into two parts, a front axis and a rear axis, and a rear end of the front axis and a front end of the rear axis are provided between the front bearing and the rear bearing. A spindle device, wherein the spindle device is integrally formed by coupling. 2. The spindle device according to claim 1, wherein a front shaft and a rear shaft of the spindle are coupled at a position overlapping a position where the built-in motor of the spindle is attached. 3. The spindle device according to claim 1, wherein a front shaft and a rear shaft of the main shaft are coupled at a position that does not overlap with a position where the built-in motor of the main shaft is mounted. 4. The motor according to claim 1, wherein a rear end of the main shaft is a male portion, a front end of the rear shaft is connected to a female portion and integrally formed, and the built-in motor is fixed to an outer periphery of a front end of the rear shaft. The spindle device according to claim 1.