JPH06264925A - Rotating apparatus with static pressure air bearing and manufacture of inner tube thereof - Google Patents

Abstract

PURPOSE:To attain a rotating apparatus which is provided with a conductive brush brought into contact with an inner tube and which can reduce an adverse effect of the rotating apparatus due to abrasion powder generated by the contact. CONSTITUTION:In this rotating apparatus which is provided with an outer tube 1, an inner tube 2 stored in the outer tube 1, a conductive brush 5 brought into contact with the inner tube 2, an object 83 brought into contact with the inner tube 2 or a member 81 mounted on the inner tube 2, a conductive detection means 9 for detecting a conductive condition to the conductive brush 5, and a static pressure air bearing where the inner tube 2 rotates in a floating condition from the outer tube 1, the inner tube 2 is provided with a protrusion 4 which extends to the outside of the outer tube 1, and the conductive brush 5 is constituted so as to be brought into contact with the protrusion 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating machine having a static pressure air bearing such as a spindle motor used in a dicing machine and a method for manufacturing an inner cylinder thereof. Particularly, in the dicing device, in order to detect the tip position when the blade is attached to the inner cylinder at the position where the blade contacts a predetermined object, the conduction between the inner cylinder and the object is detected. , A rotating device having a conductive brush that contacts an inner cylinder that floats and rotates for them.

[0002]

2. Description of the Related Art A rotating device having a hydrostatic air bearing is a device that rotates at a high speed because the rotating body rotates in a state of being levitated from an outer cylinder, so that there is no wear on the bearing portion and it can rotate at a high speed. Widely used. Even in a dicing machine used to cut IC chips from a semiconductor wafer, it is necessary to rotate a cutting blade (blade) in which abrasive grains such as diamond are fixed with nickel etc. at high speed to perform processing, so that durability of the bearing portion is improved. In consideration of the property, an air bearing is used in which an inner cylinder that rotates by the action of gas or the like floats above the outer cylinder and rotates. A motor having such a rotating mechanism is called a spindle motor.

The blades wear with use and the outer diameter decreases gradually. The tip position of the blade needs to be accurately controlled because it relates to the amount of cut, and the outer circumference of the blade is detected with high accuracy so that high-precision machining can always be performed. To detect the outer circumference of the blade,
The optical method may be used, but the most practical method is to gradually bring the rotating blade closer to the surface of the conductive stage on which the workpiece is placed, and detect the moment when the blade contacts the surface of the conductive stage. Is. To detect the moment of contact between the blade and the surface of the conductive stage,
There is a method of detecting sparks generated when they come into contact with each other, but the most general method is to detect that the blade and the conductive stage are electrically connected. As described above, it is common to use a metal such as nickel as a binder for the blade, and since the blade has conductivity, if the conduction between the conductive stage and the blade or the inner cylinder is detected, The moment when the blade contacts the surface of the conductive stage can be detected.

It is necessary to detect continuity while the blade is rotating, but it is difficult to directly contact the continuity detecting terminal with the blade. Therefore, a conductive brush is brought into contact with the inner cylinder of the spindle motor to establish continuity. Is being detected. FIG. 5 is a diagram showing a configuration of a dicing device having a function of detecting that the blade has come into contact with the conductive stage. Figure 5
In FIG. 1, reference numeral 1 is an outer cylinder, and has an air path 3 through which the gas supplied from the air supply port 31 and blown out from the gas ejection port passes. Reference numeral 2 denotes an inner cylinder housed in the outer cylinder 1, which rotates at high speed in a state of being floated from the outer cylinder 1 by the compressed air blown from the gas ejection port of the outer cylinder 1. Reference numeral 5 denotes a conductive brush, which comes into contact with the side surface of the inner cylinder 2 near the center of rotation. 7
Is a holding member made of an insulating material for holding the conductive brush 5. Reference numerals 11 and 12 are coils forming a motor. Reference numeral 81 is a blade, which is attached to a pedestal 82 provided at the tip of the inner cylinder 2. Reference numeral 83 is a conductive stage on which a workpiece is placed, and 9 is a conduction detector that detects conduction between the conductive brush 5 and the conductive stage 83. In the drawings, common parts are denoted by the same reference numerals.

To detect the tip position of the blade 81,
The blade 81 gradually moves downward while rotating the blade 81 until the continuity detector 9 detects continuity, contacts the conductive stage 83, and when the continuity detector 9 detects continuity, the blade 81
Is stopped and the position of the blade 81 at that time is read. In the above-described operation of detecting the tip position of the blade 81, if the contact between the conductive brush 5 and the inner cylinder 2 is incomplete, the blade 81 is in contact with the conductive stage 83 but is not in contact therewith. It is determined that the blade 81 and the conductive stage 8 are to be lowered in order to continue lowering.
There is a problem that 3 is damaged. In order to prevent such a problem, two conductive brushes 5 are provided, and the conductivity between them is detected to confirm the contact between the conductive brush 5 and the inner cylinder 2, and then the blade 81 and the conductive material It is considered to detect the conduction with the stage 83. However, when two conductive brushes 5 are provided, the contact position of the conductive brush 5 with the inner cylinder 2 must be displaced from the center of rotation of the inner cylinder 2, which causes a problem of abrasion of the conductive brush 5. .

Therefore, the present applicant discloses a spindle motor in which the conductive brush 5 is separated from the inner cylinder 2 when it is not necessary to detect the tip position of the blade 81 in order to prevent wear.

[0007]

In any case, in the spindle motor in which the conductive brush 5 is brought into contact with the inner cylinder 2, the conductive brush 5 is in contact with the inner cylinder 2 so that it is rotated depending on the rotation. Abrasion powder and debris of the conductive brush 5 and the inner cylinder 2 are created, and these abrasion powder and debris enter between the outer cylinder 1 and the inner cylinder 2 of the spindle motor to keep the space between the outer cylinder 1 and the inner cylinder 2 constant. There is a problem that it becomes an obstacle to hold at the interval.

Further, as described above, in order to confirm that the conductive brush 5 is in contact with the inner cylinder 2, it is necessary to provide two conductive brushes 5. In that case, The problem of wear arises, and in order to avoid this problem, another mechanism must be provided, and the spindle motor becomes large and expensive accordingly. Making the conductive brush 5 contact the inner cylinder 2 not only detects the tip position of the blade, but also detects that the inner cylinder contacts the outer cylinder during rotation due to imbalance, for example. If done also. In that case, a similar problem occurs.

The present invention has been made in view of the above problems, and in a rotating machine having a hydrostatic air bearing having a conductive brush that contacts an inner cylinder, wear powder that enters between the outer cylinder and the inner cylinder. An object of the present invention is to reduce debris and to realize a mechanism for confirming that the conductive brush is in contact with the inner cylinder with a simple structure.

[0010]

In order to achieve the above object, in a rotating machine having a hydrostatic air bearing of the present invention, a protrusion extending from the inner cylinder to the outside of the outer cylinder is provided, and a conductive brush is attached to the protrusion. Make contact. FIG. 1 is a partial cross-sectional view showing the basic structure of a rotating device having a hydrostatic air bearing of the present invention.

As shown in FIG. 1, a rotating device having a hydrostatic air bearing according to the present invention comprises an outer cylinder 1, an inner cylinder 2 housed in the outer cylinder 1, and a conductive brush 5 which contacts the inner cylinder 2. And an object 83 with which the inner cylinder 2 or a member 81 attached to the inner cylinder 2 contacts
In a rotary device having a static pressure air bearing that is provided with a conduction detecting unit 9 that detects conduction between the inner cylinder 2 and the conductive brush 5, and the inner cylinder 2 rotates while floating above the outer cylinder 1. The conductive brush 5 is provided with the protrusion 4 extending to the outside of the cylinder 1.
Are arranged so as to contact the protrusions 4.

Further, in the rotating device having the hydrostatic air bearing according to the second aspect of the present invention, two conductive brushes 5 which are insulated from each other except the path through the protrusion 4 are used as the conductive brushes.
1, 52 and a brush-to-brush conduction detecting means for detecting conduction between the two conductive brushes 51 and 52. Further, in the rotating device having the hydrostatic air bearing according to the third aspect of the present invention, the protrusion 4 is a protrusion member screwed to the inner cylinder 2.

Further, the manufacturing method of the present invention for manufacturing the inner cylinder of the rotating machine according to the third aspect includes a step of forming a screw hole for mounting the protruding member on the inner cylinder 2 and a dummy member for mounting the dummy member in this screw hole. Of the inner cylinder 2 while chucking a part of the inner cylinder 2 to hold the inner cylinder 2, a step of attaching a protruding member to the screw hole and assembling the rotating machine itself, and rotating the inner cylinder 2 of the assembled rotating machine. And a step of processing the projecting member while operating as described above.

[0014]

In the rotating device having the static pressure air bearing of the present invention, the contact between the inner cylinder 2 and the conductive brush 5 is made at the portion of the protrusion 4 extending to the outside of the outer cylinder 1. Outer cylinder 1 and inner cylinder 2
Since compressed air is blown out between the outer cylinder 1 and the outer cylinder 1, even if the conductive brush 5 or the abrasion powder or the fragments of the projection 4 is generated in the protrusion 4, the outer cylinder 1 and the inner cylinder may be generated. It doesn't get in between the two.

Conventionally, the conductive brush 5 was brought into contact with the side surface of the inner cylinder 2, but when the two conductive brushes are brought into contact with each other, the two conductive brushes pass through the inner cylinder 2. Since it is necessary to insulate other than, at least one is the inner cylinder 2
I had to make contact with a position off the center of rotation. Therefore, a problem of abrasion of the conductive brush 5 and the inner cylinder 2 occurs, and it is necessary to provide another mechanism in order to avoid the problem, and there is a problem that the rotating device becomes large and expensive accordingly. However, in the rotating device of the present invention, the conductive brush can be brought into contact with the distant positions on the peripheral surface of the protrusion 4 having a small diameter, and there is no such problem.

However, it is required that the outer cylinder 1 and the inner cylinder 2 of a rotary machine having a hydrostatic air bearing be machined with high precision.
At present, it is actually very difficult to provide the projection 4 on the inner cylinder 2. Since the protrusion 4 extends to the outside of the outer cylinder 1,
It is necessary that its diameter is small and that it is located at the center of rotation of the inner cylinder 2. In order to process the inner cylinder 2, it is necessary to chuck and hold a portion including the center of rotation of the inner cylinder 2, but such holding cannot be performed in the state where the projection 4 is provided.
Therefore, in the rotating device of the present invention, the protrusion member is used as the inner cylinder 2.
Make a protrusion 4 by screwing it on. And such a protrusion 4
In the manufacturing method of the present invention for manufacturing the inner cylinder 2 having the following, after the inner cylinder 2 is formed with a screw and the dummy member is screwed to the inner cylinder 2,
After that, the projection member is attached instead of the dummy member to assemble the device, and then the projection member is processed while operating the device, that is, while rotating the inner cylinder 2 and the projection member. The inner cylinder 2 needs to be precisely balanced, and it is not possible to realize the necessary balance state simply by screwing the protruding member. However, according to the manufacturing method of the present invention, the rotating device is assembled. Since the protrusion member is processed while rotating the inner cylinder 2 and the protrusion member, a precise balance state can be realized. This process is for precise balance, so a small amount of processing is sufficient.
Since it is not necessary to rotate the inner cylinder 2 at a high speed as in normal use, this processing does not damage the rotating device.

[0017]

FIG. 2 is a diagram showing the configuration of an embodiment in which the present invention is applied to a spindle motor of a dicing device. In FIG. 2, reference numeral 1 is an outer cylinder of the spindle motor,
Reference numeral 2 denotes an inner cylinder (rotor) housed in the outer cylinder 1. Inner cylinder 2
A pedestal 82 is provided at the tip of the blade, and the blade 81 is attached thereto. 3 is supplied from the air supply port 31,
It is a path of the compressed air blown out from the ejection port. Inner cylinder 2
The surface of the inner cylinder 2 and the surface of the outer cylinder 1 are precisely processed to form a minute gap, and the compressed air blown from the ejection port is filled in this gap, so that the inner cylinder 2 floats above the outer cylinder 1. Rotate.

Reference numeral 4 denotes a projection extending from the center of rotation on the side surface of the inner cylinder 2, and a projection member is screwed into a screw hole 41 of the inner cylinder 2. The tip of the protrusion 4 extends to the outside of the outer cylinder 1. Two conductive brushes 51 and 52 are provided so as to come into contact with the peripheral surface of the protrusion 4, and are made of carbon fiber. The two conductive brushes 51 and 52 are arranged so as to face each other with the projection 4 interposed therebetween as shown in the drawing, and are insulated from each other except for the path through the projection 4. An electrically insulating member 7 holds the conductive brushes 51 and 52. The compressed air blown into the minute gap between the surface of the inner cylinder 2 and the surface of the outer cylinder 1 is blown out from the hole of the outer cylinder 1 at a portion where the protrusion 4 is present, and passes through the hole of the member 7 to the outside. Blow out. Therefore, the abrasion powder and the carbon fiber fragments generated at the protrusion 4 and the conductive brushes 51 and 52 do not enter the inside of the spindle motor but go outside.

Reference numeral 83 denotes a conductive stage, which is 91 to 9
6 is a portion for detecting whether or not the blade 81 is in contact with the conductive stage 83, and two conductive brushes 51, 52.
It is a part that detects continuity between the two. Reference numeral 91 is a DC power source that outputs a voltage V, 92 and 94 are resistors, and 93 and 9
Reference numeral 6 is a comparator, and 95 is a reference power source that outputs a reference voltage VR lower than the voltage V.

First, a circuit for detecting conduction between the two conductive brushes 51 and 52 will be described. When the two conductive brushes 51 and 52 are both in contact with the protrusion 4, a circuit from the DC power source 91 to the two conductive brushes 51 and 52 and the protrusion 4 to the ground via the resistor 92. Is formed. Therefore, the DC power source 9 is connected to one end of the resistor 92.
A potential close to the voltage V of 1 is generated. Since this potential is higher than the potential of the reference voltage VR input to the comparator 93, an output corresponding to it is obtained from the comparator 93. If even one of the two conductive brushes 51, 52 is not in contact with the protrusion 4, the above circuit is disconnected and the potential at the end of the resistor 92 is lower than the reference voltage VR. Then, the output of the comparator 93 changes. Therefore, by observing the output of the comparator 93, the two conductive brushes 51 and 52 are both projected.
You can determine whether or not you are in contact with.

When the blade 81 is in contact with the conductive stage 83, the DC power supply 91 extends from the projection 4, the inner cylinder 2, the base 82, the blade 81, the conductive stage 83, and the resistor 9.
A circuit is formed through 4 to ground. Therefore, a potential close to the voltage V of the DC power supply 91 is generated at one end of the resistor 94. Since this potential is higher than the potential of the reference voltage VR input to the comparator 93, the comparator 96
Will give you the corresponding output. When the blade 81 is not in contact with the conductive stage 83, this circuit is cut off, the potential at the end of the resistor 94 becomes a ground potential lower than the potential of the reference voltage VR, and the output of the comparator 96 changes. Therefore, by looking at the output of the comparator 96, it can be determined whether or not the blade 81 is in contact with the conductive stage 83.

When detecting the tip position of the blade 81,
First, after confirming that the two conductive brushes 51 and 52 are both in contact with the protrusion 4, the blade 81 is lowered, and when the blade 81 contacts the conductive stage 83, the blade 81 is stopped and Detect the position. Next, a method of manufacturing the inner cylinder 2 including the protrusion 4 will be described with reference to FIG. The shape of the inner cylinder 2 in FIG. 3 is different from that in FIG. 2 for the sake of simplicity.

The inner cylinder 2 and the projection member 42 are already machined to some extent with sufficient accuracy, but it is not sufficient to complete a spindle motor. In that state,
As shown in (1) of FIG.
Next, the inner cylinder 2 is precisely processed. For that purpose, it is necessary to chuck and hold a portion including the center of rotation of the inner cylinder 2 and then rotate the inner cylinder 2 for processing. But screw holes 41
Is formed in the portion including the center of rotation of the inner cylinder 2,
It cannot be chucked as it is. Therefore, (2) in FIG.
As shown in, the dummy member 43 is screwed into the screw hole 41 and then chucked to process the inner cylinder 2. As a result, the inner cylinder 2 is processed with high precision, so that the dummy member 43 is removed and the protrusion member 42 is screwed in to assemble the spindle motor itself. In this state, the balance of the inner cylinder 2 itself does not pose any problem, but the balance of the projection member 42 is slightly insufficient, and it is necessary to make a fine balance adjustment with respect to the rotation center of the inner cylinder 2. Therefore, as shown in (3) of FIG. 3, the spindle motor itself is operated to rotate the inner cylinder 2 to process the protruding member 42. Since this processing is a minute processing, the rotation speed of the inner cylinder 2 may be lower than that during normal use, a load is hardly applied, and the spindle motor is not adversely affected.

In the manufacturing method of FIG. 3, the screw hole 41 is provided to attach the protruding member 42 to the inner cylinder 2, but as shown in FIG. You may make it attach by providing a female screw on the 44 side.
Further, in order to rotate the protrusion member for screwing it into the inner cylinder 2, the peripheral surface may be formed in a hexagonal shape, but for good balance, it is for a crab eye whose tip is fitted to the side surface. A structure with holes is desirable.

[0025]

As described above, in the rotating device having the hydrostatic air bearing of the present invention, since the inner cylinder and the conductive brush are contacted with each other outside the outer cylinder, abrasion powder and debris are generated in the rotating device. It will not get inside and the reliability of rotating equipment will be improved. Also, since the freedom of attaching the conductive brush increases,
It also becomes easy to confirm the contact between the inner cylinder and the conductive brush. Furthermore, the inner cylinder for realizing such a rotating device can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic structure of a rotating device having a hydrostatic air bearing of the present invention.

FIG. 2 is a diagram showing a configuration of an embodiment in which the present invention is applied to a spindle motor of a dicing device.

FIG. 3 is an explanatory diagram of a method of manufacturing an inner cylinder.

FIG. 4 is an explanatory view of another example of the method for manufacturing the inner cylinder.

FIG. 5 is a diagram showing a configuration of a spindle motor in a conventional dicing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer cylinder 2 ... Inner cylinder 3 ... Air supply path 4 ... Protrusion 5 ... Conductive brush 9 ... Continuity detection means 81 ... Cutting blade (blade) 83 ... Conductive stage

Claims (5)

[Claims] 1. An outer cylinder (1), an inner cylinder (2) housed in the outer cylinder (1), a conductive brush (5) in contact with the inner cylinder (2), and the inner cylinder (2). 2) or a conduction detecting means (9) for detecting conduction between the object (83) with which the member (81) attached to the inner cylinder (2) contacts and the conductive brush (5), A rotary device having a hydrostatic air bearing that rotates in a state where the inner cylinder (2) floats above the outer cylinder (1), wherein the inner cylinder (2) is a protrusion extending to the outside of the outer cylinder (1). (4), The said electroconductive brush (5) is arrange | positioned so that the said protrusion (4) may be contacted, The rotary apparatus which has a hydrostatic air bearing characterized by the above-mentioned. 2. The conductive brush comprises two conductive brushes (51, 52) insulated from each other except a path through the protrusion (4). Sex brush (51, 52)
The rotating device having a hydrostatic air bearing according to claim 1, further comprising a brush-to-brush conduction detecting means for detecting conduction between the brushes. 3. The projection (4) is a projection member screwed to the inner cylinder (2).
Or a rotating device having the static pressure air bearing according to item 2. 4. A method for manufacturing an inner cylinder of a rotating device having a hydrostatic air bearing according to claim 3, wherein a screw hole (41) for attaching the protruding member (42) to the inner cylinder (2) is provided. A step of forming the inner cylinder (2) while attaching a dummy member (43) to the screw hole (41) and chucking a part of the dummy member (43) to hold the inner cylinder (2) And the step of assembling the rotating device, and attaching the protruding member (42) to the screw hole (41), and causing the inner cylinder (2) of the assembled rotating device to rotate. However, the process of manufacturing the said protrusion member (42) is provided, The manufacturing method of the inner cylinder of the rotating equipment which has a static pressure air bearing characterized by the above-mentioned. 5. A method of manufacturing an inner cylinder of a rotating device having a hydrostatic air bearing according to claim 3, wherein the inner cylinder (2) is provided with an external thread (21) for attaching the protruding member (42). And a step of processing the inner cylinder (2) while chucking a part of the male thread (21) to hold the inner cylinder (2), and the male thread (21). Attaching the protruding member (42) to the assembly, assembling the rotating device, and processing the protruding member (42) while rotating the inner cylinder (2) of the assembled rotating device. And a method for manufacturing an inner cylinder of a rotating device having a hydrostatic air bearing.