JPH04275803A - Spindle stock device of machine tool - Google Patents

Abstract

PURPOSE:To increase the supporting rigidity of a spindle so as to improve the working accuracy in a built-in motor type spindle stock device. CONSTITUTION:Plural rotors 12 and stators 13 of a motor 11 for driving a spindle 4 are disposed side by side in the axial direction of each spindle 4. A bearing 9 for supporting the spindle 4 is provided between these plural stators 13.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle stand device for a machine tool that is applied to machining centers, turning centers, lathes, and the like.

0002

2. Description of the Related Art Conventionally, in order to make the spindle stand more compact, as shown in FIG. A stand device has been proposed.

In this type of spindle stand device, the spindle 53 is mounted on bearings 55 provided at both ends of the spindle stand 54.
, 56, and the motor 51 is disposed at an intermediate position between the positions supported by these bearings 55, 56.

0004

[Problems to be Solved by the Invention] However, with such a spindle support structure, the support rigidity decreases in the middle portion of the spindle 53 that is not supported by the bearings 55 and 56, causing flexural deformation, resulting in a decrease in machining accuracy. There is a problem with that.

An object of the present invention is to provide a spindle stand device for a machine tool that can increase the support rigidity of the spindle and improve the machining accuracy.

[0006]

[Means for Solving the Problems] The structure of the present invention will be explained with reference to FIG. 1 corresponding to an embodiment. This invention provides a spindle stand device with a built-in motor.
A plurality of rotors (12) and stators (13) of the motor (11) that drive the motor (4) are arranged in parallel in the axial direction of the spindle (4), and between the plurality of stators (13), the spindle (4) A bearing (9) is provided to support the. The rotor (12) is attached to the outer periphery of the spindle (4), and the stator (13) is built into the spindle stand (3).

[0007]

[Operation] Spindle (4) on which the motor (11) is arranged
Since the middle part of the spindle (
4) The overall support rigidity is increased, and a decrease in processing accuracy due to bending deformation is avoided. Further, since a plurality of rotors (12) and stators (13) of the motor (11) are arranged in parallel in the axial direction of the spindle (4), the surface area of the motor (11) becomes large and the cooling effect increases.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 2 shows a column section of a machining center. In the figure, a spindle stand 3, which is a spindle head, is installed on a rail 2 of a column 1 so as to be movable up and down. The spindle stand 3 is constructed by installing a cylindrical housing 5 supporting a spindle 4 on an elevating table 6.

As shown in FIG. 1, the spindle 4 has a tool mounting hole 7 at the front end on which various tools can be attached interchangeably, and is comprised of a front bearing 8, an intermediate bearing 9, and a rear bearing 10. It is rotatably supported by a spindle stand 3.

The motor 11 that drives the spindle 4 is a built-in type synchronous motor that is integrated into the spindle base 3, and the motor 11 is a built-in type synchronous motor that is integrated into the spindle base 3.
It consists of two rotors 12, 12, which are integrally attached to the front and rear parts thereof, respectively, and two stators 13, 13, etc., which are provided at respective positions on the inner periphery of the cylindrical housing 5 corresponding to these rotors 12. That is, here, substantially two motors 11, 11 are arranged in parallel, front and back, with the intermediate bearing 9 in between.

Each rotor 12 is made up of a plurality of permanent magnets, and each stator 13 is made up of a stator core 13a and a stator coil 13b. Further, a cooling jacket 14 is interposed between each stator 13 and the cylindrical housing 5. This cooling jacket 14 is formed with a spiral cooling liquid passage 14a for circulating the cooling liquid. In addition, front and rear 2
The output of each of the two motors 11, 11 is set to 1/2 of the output required to drive the spindle 4, respectively.

The cylindrical housing 5 also has a cooling air inlet 16 for blowing cooling air into the front side of the motor installation space 15 on the outer periphery of the spindle 4, and a cooling air inlet 16 for blowing cooling air into the front side of the motor installation space 15 on the outer periphery of the spindle 4, and a cooling air inlet 16 for blowing cooling air into the front side of the motor installation space 15 on the outer periphery of the spindle 4. The flange portion 5a of the inner peripheral surface of the cylindrical housing 5 that supports the intermediate bearing 9 has a communication hole that communicates the front side and the rear side of the motor installation space 15. 18 is formed, and the motor 11 is air-blown cooled by the cooling air.

The operation of the above configuration will be explained. spindle 4
is rotationally driven by a motor 11 built into the spindle stand 3, and performs cutting with a tool (not shown) mounted in the tool mounting hole 7. The spindle 4 is supported at the front and rear by a front bearing 8 and a rear bearing 10, and at the middle by an intermediate bearing 9, so it has high support rigidity and hardly bends or deforms. Therefore, the center of rotation of the tool does not shift during the rotational drive, and highly accurate cutting can be performed.

The rotation of the spindle 4 causes each part of the motor 11 and the front, middle, and rear bearings 8 and 9 to be rotated.
. This prevents a decrease in the rigidity of the spindle 4 due to thermal deformation.

In this spindle stand 3, a combination of a rotor 12 and a stator 13 constituting a motor 11 is divided into two sets and arranged in parallel in the axial direction of the spindle 4 with an intermediate bearing 9 in between. Since the surface area of the cooling jacket 11 is increased accordingly, a sufficient covering area of the cooling jacket 14 can be ensured, and the cooling effect due to the water cooling action described above is enhanced. Similarly, the cooling effect due to air cooling is also improved.

Although it is undeniable that the outer shape of the motor 11 becomes a little larger in the above configuration, each combination of the rotor 12 and the stator 13 in the front and rear is connected to the spindle 4 as described above.
It is only necessary to share 1/2 of the output required for the rotational drive of the two. Therefore, the structure of the rotor 12 and stator 13 in each combination is correspondingly smaller, and the outer diameter is rather smaller, so the volume is not very large, and the overall shape is slightly extended in the axial direction of the spindle 4. It just becomes. In the case of column feed type machining, such an elongated shape is rather advantageous in increasing the rigidity of the column.

[0017] In the above configuration, two motors 11,
11 are arranged side by side in front and behind with the intermediate bearing 9 in between. However, for example, a current input to the front stator 13 is outputted from the rear stator 13, so that substantially one motor is used. 11 may be adopted. Further, the motor 11 may be configured as a DC motor or an induction motor. Further, in the above embodiment, the spindle 4 is used to attach a tool, but the present invention can also be applied to a spindle that rotates a workpiece.

FIG. 3 shows a turning center in which the present invention is applied to a spindle for rotating a workpiece. This turning center includes a main shaft 19 whose position is fixed, a sub-spindle 20 that can face the main shaft 19, a turret 21, and a milling head 22. The sub-spindle 20 receives the work W from the main shaft 19 and rotates it.
The spindle stand 23 is supported movably in two axes U and W directions. The present invention is applied to the spindle stand 23 of this sub-spindle 20.

[0019]

[Effects of the Invention] In the machine tool spindle stand device of the present invention, the intermediate portion of the spindle in which the motor is arranged is supported by a bearing, and a plurality of rotors and stators of the motor are arranged in parallel in the axial direction of the spindle with the bearing in between. This increases the support rigidity of the spindle and improves machining accuracy. Furthermore, since the overall shape of the motor extends in the axial direction of the spindle, the surface area of the motor becomes larger, which increases the cooling effect accordingly.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

FIG. 2 is a cutaway perspective view of a column section of a machine tool to which the spindle stand device is applied.

FIG. 3 is a schematic perspective view of a turning center to which the spindle head device is applied.

FIG. 4 is a sectional view showing a conventional example.

[Explanation of symbols]

Claims (1)

[Claims] 1. A spindle stand device in which a rotor of a motor that drives a spindle is attached to the outer periphery of the spindle, and a stator of the motor is incorporated in a spindle stand, wherein a plurality of rotors and stators are arranged in parallel in the axial direction of the spindle. between these multiple stators.
A spindle stand device for a machine tool, which is provided with a bearing that supports the spindle.