JPH07208474A - Air spindle and equipment equipped with it - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an air spindle that has a small amount of heat generation, does not adversely affect the thermal deformation of the spindle, and prevents the rotation torque of the spindle from becoming unstable due to changes in the cutting load. Improve the processing accuracy of cutting equipment and precision grinding equipment. In an air spindle having a spindle and a spindle housing that supports the spindle with air, a drive source of the spindle is a synchronous motor. The air spindle is mounted on a precision cutting device, and a cutting blade is attached to the tip of the spindle.
The air spindle is mounted on a precision grinding machine, and a grinding wheel is attached to the tip of the spindle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air spindle and an apparatus equipped with it.

[0002]

2. Description of the Related Art An air spindle is usually incorporated in a precision cutting device, a precision grinding device, etc. for processing a workpiece such as a semiconductor wafer. This air spindle includes a spindle and a spindle housing for supporting the spindle with air. It has the function of rotating a rotating blade or a grinding wheel mounted on the tip of the spindle.

[0003]

In the conventional air spindle, a high-frequency induction motor (induction motor) is generally used as a motor for rotating the spindle. However, since the amount of heat generation is large, the spindle is adversely affected by thermal deformation. However, there is a problem that high-precision machining becomes impossible. Further, there is a problem that the rotational torque of the spindle becomes unstable due to the change of the cutting load, which lowers the work efficiency and increases the vibration generated by the rotation. Therefore, the precision of a precision cutting device, a precision grinding device, etc. equipped with such an air spindle lowers the processing accuracy.
The present invention has been made to solve such conventional problems, and has a small amount of heat generation so that the spindle is not adversely affected by thermal deformation, and the rotation torque of the spindle does not become unstable due to a change in cutting load. An object is to provide an air spindle and improve the processing accuracy of a precision cutting device, a precision grinding device, and the like.

[0004]

As means for technically solving the above-mentioned problems, the present invention relates to an air spindle having a spindle and a spindle housing for supporting the spindle with air, and a drive source for the spindle. The gist is that it is a synchronous motor. Further, the gist is a precision cutting device in which the air spindle having the above-mentioned configuration is mounted and a cutting blade is attached to the tip of the spindle. Further, it is a gist of a precision grinding apparatus in which an air spindle having the above-mentioned configuration is mounted and a grinding wheel is mounted on the tip of the spindle.

[0005]

[Operation] Since a synchronous motor is used as the drive source of the air spindle, the amount of heat generated is small and the spindle is not adversely affected by thermal deformation, and the spindle slip (rotation loss) is minimized even when the cutting load increases. Rotation torque does not become unstable. Therefore, it is possible to improve the processing accuracy of a precision cutting device, a precision grinding device, etc. equipped with this air spindle.

[0006]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a spindle housing in which a spindle 2 and a known synchronous motor 3 for rotating the spindle 2 are provided.

The synchronous motor 3 has a rotor 3a and a stator 3b, and the spindle 2 is rotated at a high speed through the rotor 3a.

The synchronous motor 3 has a very small amount of heat generation when it is rotated at a high speed, and the spindle housing 1
Almost no temperature rise is observed. FIG. 2 is a graph showing changes in temperature of the spindle housing when the spindle is rotated at a rotation speed of 40,000 rpm in an unloaded state. However, the supply pressure to the spindle housing 1 is 5.0
A kgf / cm ^2, cooling water flow rate to the water jacket for cooling the spindle housing (not shown) was 1.4 liters / minute.

As a result, in the case of the conventional induction motor, the temperature of the outer peripheral portion of the spindle housing reaches 45 ° C. in only 5 minutes after the start of operation, whereas in the case of the synchronous motor 3, the temperature of the spindle housing is increased. The temperature of the outer peripheral part is about the same as room temperature (about 22 ° C).
The temperature remained almost unchanged after 0 minutes. Therefore, it was found that the spindle 2 mounted inside the spindle housing 1 hardly changed in temperature and was not adversely affected by thermal deformation.

Further, according to the synchronous motor 3, the rotational torque of the spindle does not become unstable due to a change in cutting load. FIG. 3 is a graph in which the relationship between the change in cutting speed and the rotational speed of the spindle was tested. However, in a cutting device with a rotating blade attached to the tip of the spindle,
The cutting material is soda glass (dimensions: 100 x 100 x 1.
3 mm) and the cutting depth was 1.0 mm.

As a result, in the case of the conventional induction motor, the initial rotational speed of the rotary blade is high, but it decreases almost proportionally as the cutting speed increases, and the cutting speed is 14 m
Sparking was observed at m / sec. On the other hand, in the case of the synchronous motor 3, the initial number of revolutions is lower than that of the induction motor, but only a gradual decrease with the increase of the cutting speed is observed, and the revolution speed is almost 6 mm /
Reverse rotation occurs in sec, that is, the synchronous motor has a higher number of revolutions, and after that it keeps an almost constant value and the cutting speed is 1
Spark generation was observed at 6 mm / sec. Therefore, it was found that the synchronous motor 3 has a more stable rotation speed, in other words, the rotation torque is more stable.

The air spindle according to the present invention is constructed as described above and is used by being mounted on, for example, a precision cutting device or a precision grinding device. That is, FIG. 4 shows an embodiment mounted on the cutting means 5 of the precision cutting device 4. As shown in detail in FIG. 5, a mounting portion 6 is provided at the tip of the spindle 2 and the mounting portion 6 is provided. The rotary blade 7 is fastened and fixed via the mounting nut 8.

In the precision cutting device 4, the workpieces such as semiconductor wafers stored in the cassette 4a are pulled out onto the pair of support tables 4c by the loading / unloading means 4b, sucked by the transporting means 4d, and swung. Then, it is conveyed onto the chuck table 4e. The chuck table 4e moves to below the alignment means 4f to precisely align the cutting portion of the workpiece, and then the chuck table 4e moves to the cutting means 5 and the rotary blade 7
A predetermined cutting process is performed at. After cutting, the chuck table 4e is returned to its original position, and the workpiece is
It is adsorbed by the conveying means 4g and conveyed to the cleaning means 4h. After being washed and dried here, the workpiece is adsorbed by the conveying means 4d and returned to the support table 4c, and is also stored at a predetermined position in the cassette 4a by the carry-in / out means 4b.

In this case, since the synchronous motor 3 is adopted as the drive source of the air spindle in the cutting means 5, the calorific value is small and the spindle 2 is not adversely affected by thermal deformation, so that high-precision machining is possible. It will be possible. Further, since the rotation speed of the spindle is stable and the rotation torque is stable, good work efficiency can be obtained, and vibration generated by rotation can be suppressed to a small level.

FIG. 6 shows an embodiment in which the air spindle according to the present invention is mounted on the grinding means 10 of the precision grinding device 9. A grinding wheel 11 is attached to the tip of the spindle 2 and the grinding wheel 11 is mounted on the grinding wheel 11. The rotary whetstone 12 is attached.

In this precision grinding apparatus 9, a work piece 13 such as a semiconductor wafer is fixed on a rotatable chuck table 9a, and while the grinding wheel 11 is rotated by the spindle 2, the rotary grindstone 12 is pressed by a predetermined force. Is pressed against the workpiece 13 to grind its surface. 9b is a moving mechanism having a ball screw for moving the grinding means 10 up and down, and 9c is a balance weight provided in association with the moving mechanism 9b.

In this case as well, since the synchronous motor 3 is used as the drive source of the grinding means 10, the amount of heat generated is small and the spindle 2 is not adversely affected by thermal deformation, enabling highly accurate grinding. become. Further, since the rotation speed of the spindle is stable and the rotation torque is stable, good work efficiency can be obtained, and vibration generated by rotation can be suppressed to a small level.

The air spindle according to the present invention is preferably mounted on the precision cutting device or the precision grinding device, but it is not limited to this and can be used by being mounted on another device or machine. .

[0019]

As described above, according to the present invention,
Since the synchronous motor is used as the drive source of the air spindle, the amount of heat generated is small and the spindle is not adversely affected by thermal deformation, and high precision machining can be maintained. Further, since the rotational speed of the spindle is stable and the rotational torque is stable, the working efficiency is remarkably improved, and vibrations caused by the rotation can be suppressed to be small. Therefore, when this air spindle is mounted on a precision cutting device, a precision grinding device, or the like, it has an effect of remarkably improving the processing accuracy.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an air spindle according to the present invention.

FIG. 2 is a graph showing a change in temperature of the spindle housing when the spindle is rotated at a high speed.

FIG. 3 is a graph showing an experiment of the relationship between the change in cutting speed and the rotation speed of the spindle.

FIG. 4 is a perspective view showing an embodiment of a precision cutting device equipped with an air spindle according to the present invention.

FIG. 5 is a perspective view of a mounting portion of the rotary blade of the same.

FIG. 6 is a fragmentary side view showing an embodiment of a precision grinding apparatus equipped with an air spindle according to the present invention.

[Explanation of symbols]

1 ... Spindle housing 2 ... Spindle 3 ...
Synchronous motor 3a ... Rotor 3b ... Stator 4 ... Precision cutting device 5 ... Cutting means 6 ... Mounting part 7 ... Rotating blade 8 ... Nut 9 ... Precision grinding device 10 ... Grinding means 11 ... Grinding wheel 12 ... Rotating grindstone 13 ... Workpiece object

Claims (3)

[Claims] 1. An air spindle having a spindle and a spindle housing for supporting the spindle with air, wherein a drive source for the spindle is a synchronous motor. 2. A precision cutting device equipped with the air spindle according to claim 1, and a cutting blade mounted on the tip of the spindle. 3. A precision grinding machine in which the air spindle according to claim 1 is mounted, and a grinding wheel is attached to the tip of the spindle.