JPH11138432A - Air spindle and grinding device equipped with the air spindle - Google Patents

Abstract

(57) Abstract: An air spindle including a spindle having a vertical axis with a tool attached to a lower end thereof, and a spindle housing rotatably supporting the spindle by a radial air bearing and a thrust air bearing. The rigidity of the spindle is increased to prevent bending. A thrust air bearing is provided in a space defined by a wheel mounter on which a processing tool is mounted and a thrust plate connected to the wheel mounter at a predetermined interval. The wheel mounter is directly supported by the air coming from.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air spindle for supporting a spindle by air from a thrust air bearing and a radial air bearing, and
The present invention relates to a grinding device equipped with the air spindle.

[0002]

2. Description of the Related Art As an air spindle of this type, an air spindle 60 having a configuration shown in FIG. 5 is well known as a conventional example. In the air spindle 60, a spindle 62 is supported by air blown in a horizontal direction and a vertical direction from a spindle housing 61.

The spindle 62 is rotatable about a vertical axis centered by a drive source (not shown) such as a motor, and has a lower end provided with a wheel mounter on which various tools 63a are mounted. A thrust plate 64 is formed above the wheel mounter 63 at a predetermined interval from the wheel mounter 63.

[0004] The spindle housing 61 is formed in a substantially cylindrical shape so as to cover the spindle 62 from the outer peripheral surface side, and is directed from a number of outlets (not shown) provided inside toward the axis of the spindle 62. A radial air bearing 65 that injects air in a horizontal direction to maintain a constant distance between the spindle 62 and a vertical air bearing 65 sandwiched between an upper thrust bearing 66 and a lower thrust bearing 67 from above and below a thrust plate 64. And a thrust air bearing 68 for supporting the spindle 62 by injecting air.

[0005] In this manner, the spindle 62 is supported by the air blown from the radial air bearing 65 and the thrust air bearing 68. When the spindle 62 rotates, various kinds of processing are performed by the tool 63a mounted on the wheel mounter 63. Is performed.

[0006]

However, since there is a relatively large space between the thrust air bearing 68 and the wheel mounter 63, the wheel mounter
In some cases, the rigidity is reduced due to the load applied by the tool 3 and the tool 63a, causing the spindle 62 to bend. This has a problem that must be solved in order to eliminate such adverse effects.

[0007]

As a specific means for solving the above problems, the present invention provides a spindle including at least a wheel mounter on which a machining tool is mounted, and a thrust plate connected to the wheel mounter. When,
An air spindle including a spindle housing that supports the spindle with a thrust air bearing and a radial air bearing. An object of the present invention is to provide an air spindle which is directly supported.

[0008] Two or more thrust plates are formed on the spindle, and an additional requirement is that a thrust air bearing is also interposed in a space formed by the facing surfaces of the thrust plates.

According to such an air spindle, since the wheel mounter is supported by the air from the thrust air bearing, the rigidity against a vertical load is increased, and the deflection of the spindle is reduced. When two or more thrust plates are formed and a thrust air bearing is also interposed in a space formed by the facing surfaces of the thrust plates, the rigidity is further increased and the bending of the spindle is further reduced. .

[0010] The present invention also includes a chuck table for holding a workpiece, and an air spindle disposed so as to face the chuck table and to have an axis perpendicular to the chuck table. A grinding device, on which the air spindle is mounted, a grinding wheel as a processing tool is mounted on a wheel mounter of the air spindle, and the workpiece held on the chuck table is ground by the grinding wheel. A grinding device is provided.

[0011] An additional requirement is that the workpiece is a semiconductor wafer.

According to such a grinding device, the rigidity of the spindle on which the grinding wheel is mounted is increased and the deflection is reduced, so that good grinding can be performed.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings. First, an air spindle 10 shown in FIG. 1 includes a spindle 11 and a spindle housing 12, and the spindle 11 forms a wheel mounter 13 on which a tool 13a is mounted at a lower end as in the conventional example. A thrust plate 14 is formed above the wheel mounter 13 at a predetermined distance from the wheel mounter 13.

A radial air bearing 15 constituting the spindle housing 12 injects air in a horizontal direction toward the axis of the spindle 11 to maintain a constant distance from the spindle 11 as in the conventional example. I have. On the other hand, unlike the conventional example, the thrust air bearing 16 is disposed in the recess 17 which is a space formed by the facing surfaces of the thrust plate 14 and the wheel mounter 13,
The thrust plate 14 is supported by air blown upward from the upper thrust bearing 18, and the back surface of the wheel mounter 13 is directly supported by air blown downward from the lower thrust bearing 19, so that the support state of the spindle 11 is balanced as a whole. ing.

Since the support state of the wheel mounter 13 is stabilized by disposing the thrust air bearing 16 in the recess 17 between the thrust plate 14 and the wheel mounter 13, the rigidity of the spindle 11 is increased. Deflection is reduced. In FIG. 1, the gap formed between the thrust air bearing 16 and the thrust plate 14 and the wheel mounter 13 is exaggerated, but is actually several μm (see FIG. 2 described later). The same applies to the example).

The air spindle may be configured as shown in FIG. In the air spindle 20 shown in FIG. 2, a first thrust plate 22 and a second thrust plate 23 are formed on a spindle 21. And
A first thrust air bearing 25 is provided in a first concave portion 24 formed by a facing surface of the first thrust plate 22 and the second thrust plate 23, and the second thrust plate 23 and the wheel mounter 26 A second thrust air bearing 28 is provided in a second recess 27 formed by the facing surface.

The first thrust plate 22 is supported by air blown upward from a first upper thrust bearing 29 constituting a first thrust air bearing 25. Also, the second thrust plate 23
Are blown downward from the first lower thrust bearing 30 forming the first thrust air bearing 25 and blown upward from the second upper thrust bearing 31 forming the second thrust air bearing 28. It is supported by being pinched by air. Further, the rear surface of the wheel mounter 26 is directly supported by air blown downward from a second lower thrust bearing 32 constituting a second thrust air bearing 28. Thus, the spindle 21 is rotatably supported as a whole.

As described above, the two thrust plates are formed, and the thrust air bearing is disposed not only in the space formed by the facing surfaces of the wheel mounter and the thrust plate, but also in the space formed by the facing surfaces of the thrust plates. Thereby, the supporting state is more stabilized than in the case of the example of FIG. 1, and the rigidity of the spindle is further increased, so that the bending hardly occurs.

It is to be noted that three or more thrust plates may be formed, and the number of thrust air bearings disposed in the space formed by the facing surfaces of the thrust plates is increased according to the number of thrust plates. In addition, the rigidity is further increased, and bending is less likely to occur.

The air spindle 10 shown in FIG.
As a device to which the air spindle 20 shown in FIG. 1 is applied, for example, a grinding device 40 as shown in FIG. In the following, the air spindle 1 shown in FIG.
3 and FIG. 4 by taking the grinding device 40 equipped with
This will be described with reference to FIG.

As shown in FIG. 3, in the grinding device 40, a wall 42 is provided upright from an end of a base 41, and a pair of rails 43 is provided on an inner surface of the wall 42. The slide plate 4 is installed along the rail 43 in the vertical direction.
The grinding means 46 attached to the slide plate 45 moves up and down following the up and down movement of 5.
A chuck table 47 for holding an object to be ground, for example, a semiconductor wafer, is rotatably provided on the base 41.

The grinding means 46 is constituted by the air spindle 10 shown in FIG. 1, and the spindle 11 is supported by the spindle housing 12 including the radial air bearing 15 and the thrust air bearing 16. A grinding wheel 13, which is a grinding tool, is provided on the tip of the spindle 11 via a wheel mounter 13.
a is attached.

When the object to be ground is ground in the grinding device 40, the object to be ground is held on the chuck table 47 and positioned immediately below the grinding means 46. Means 4
6 is lowered.

The operation of the grinding apparatus 40 will be described with reference to FIG.
, The pulse motor 51 is driven via the pulse motor driver 50, and the rotation of the ball screw 52 accompanying the rotation of the pulse motor 51 causes the drive unit 53 screwed to the ball screw 52 to be lowered. When the drive unit 53 descends,
The slide plate 45 connected to the drive unit 53 also moves down along the rail 43, and the grinding means 46 attached to the slide plate 45 moves down following the slide plate 45. Also, spindle 1
The drive source 48 provided on the top of the unit 1 is connected to the control unit 49 and drives the rotation of the spindle 11 under the control of the control unit 49.

When the drive unit 53 descends, the position information of the drive unit 53 is detected by the linear scale 54 disposed outside the wall 42, and the position information is transferred to the control unit 49. Then, the transferred position information is transmitted to the control unit 49.
Is provided for precise control of the vertical movement of the grinding means 46 in FIG.

The control unit 49 includes a servo driver 55
Is connected to an encoder 56 and a servo motor 57 disposed below the chuck table 47, and the chuck table 47 is rotatable by driving the encoder 56 and the servo motor 57.

In this way, the grinding means 46 descends,
An appropriate pressing force is applied to the object to be ground by the rotating grinding wheel 13a, and the surface of the object to be ground is ground. Unlike the related art, the wheel mounter 13 is directly supported by the air blown from the thrust air bearing 16, and the rigidity of the spindle 11 is increased and the deflection is reduced, so that good grinding can be performed.

[0028]

As described above, in the air spindle according to the present invention, since the wheel mounter is supported by the air from the thrust air bearing, the rigidity against the vertical load is increased, and the bending of the spindle is reduced. When two or more thrust plates are formed and a thrust air bearing is also interposed in the space formed by the facing surfaces of the thrust plates, the rigidity is further increased and the bending of the spindle is further reduced. . Therefore, the accuracy of various types of processing using the tool mounted on the spindle is improved.

Further, in the grinding device according to the present invention, the rigidity of the spindle on which the grinding wheel is mounted is increased, the deflection is reduced, and good grinding can be performed, so that the quality of the workpiece is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a first embodiment of an air spindle according to the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a second embodiment of the air spindle.

FIG. 3 is a perspective view showing a part of the external appearance of a grinding device equipped with the air spindle.

FIG. 4 is an explanatory diagram showing a configuration of the grinding device.

FIG. 5 is an explanatory diagram showing a configuration of a conventional air spindle.

[Explanation of symbols]

10 air spindle 11 spindle 12 spindle housing 13 wheel mounter 13a grinding wheel 14 thrust plate 15 radial air bearing 16 thrust air bearing 17 recess 18 upper thrust Bearing 19 ……
Lower thrust bearing 20 Air spindle 21 Spindle 22 First thrust plate 23 Second thrust plate 24 First concave portion 25 First thrust air bearing 26 Wheel mounter 27 ... Second concave portion 28 Second thrust air bearing 29 First upper thrust bearing 30 First lower thrust bearing 31 Second upper thrust bearing 32 Second lower thrust Bearing 40 Grinding device 41 Base 42 Wall 43 Rail 45 Slide plate
46 Grinding means 47 Chuck table 48 Driving source 49
Control unit 50: Pulse motor driver 51: Pulse motor 52: Ball screw 53: Drive unit 54: Linear scale 55: Servo driver 56: Encoder 57: Servo motor 60: Air spindle 61: Spindle Housing 62 ... Spindle 63 ... Wheel mounter 63
a tool 64 thrust plate 65 radial air bearing 66 upper thrust bearing 67 lower thrust bearing 68 thrust air bearing

Claims (4)

[Claims] 1. A spindle including at least a wheel mounter to which a tool for processing is mounted, a thrust plate connected to the wheel mounter, and a spindle housing supporting the spindle by a thrust air bearing and a radial air bearing. An air spindle comprising: a thrust air bearing interposed in a space defined by a face of the wheel mounter and the thrust plate to directly support a rear surface of the wheel mounter. 2. The air spindle according to claim 1, wherein two or more thrust plates are formed on the spindle, and a thrust air bearing is also interposed in a space formed by facing the thrust plates. 3. A grinding apparatus comprising: a chuck table for holding a workpiece; and an air spindle opposed to the chuck table and disposed so that an axis thereof is perpendicular to the chuck table. A workpiece to which the air spindle according to claim 1 or 2 is mounted, a grinding wheel as a processing tool is mounted on a wheel mounter of the air spindle, and the chuck table is held by the grinding wheel with the grinding wheel. Grinding equipment for grinding. 4. The grinding apparatus according to claim 3, wherein the workpiece is a semiconductor wafer.