JPS62152621A - Method of machining air groove in air bearing - Google Patents

Abstract

PURPOSE:To make it possible to enhance the accuracy of machining and to establish the technology of machining for mass production, by aligning the projecting end face of an electrode with the surface of a bearing to be machined so that the position of electric discharge machining is rotated along the surface of the bearing to be machined to form a groove, and thereafter by separating the electrode. CONSTITUTION:A positioning and lowering means positions an electrode holder 4 to which an electrode is set, to a shaft 6 to be machined, and is lowered down to a predetermined level. Further, the electrical discharge gap is set to a predetermined value depending upon the depth of an air groove. With a predetermined gap being held between a shaft holder jig 5 and the inner peripheral surface of the electrode, the jig 5 is eccentrically rotated, and the value of current for electrical discharge is set in accordance with the surface rough ness of the air groove, and electric discharge machining is carried out. The electrode holder 4 having completed a swing-machining step is raised from the machined shaft, then is positioned to a predetermined position for the next shaft to be machined and lowered to it so that electrical discharge is carried out for the next shaft. Due to such electric discharge machining, an air groove may be machined at the final machining step, and therefore, the machining of an air groove in an air bearing having a high degree of accuracy may be made in a highly effective mass production base with no machining sagging.

Description

[Detailed Description of the Invention] [IRi Field of the Invention] The present invention provides air +
This relates to the method of adding air 1 (η) in hl+receiving.

L conventional ridge? +Fi and its problems (S) Kin 11 Te, 'l': A laser beam printer that applies a conductor laser has been developed.In this laser beam printer, information such as manuscripts can be transferred to the tEki Igo issue. An optical deflector using a polygonal mirror is used for the conversion.This polygonal mirror generally has a regular polygonal shape, and its 111
Each has a reflective surface with a mirrored front lens. The multibody mirror is coaxially mounted on a rotatable spindle, and is rotated by the spindle to reflect incident light in different directions. In order to obtain high resolution in the conversion of the hypochondriacal signal of 1"f, L, it is necessary to increase the rotational speed of the spindle (104 rpm or more) and increase the deflection speed of the light. Furthermore, the conversion means Since an optical system is used as the optical system, it is necessary to maintain the positional accuracy of the multi-m body mirror with extremely high accuracy, and for this purpose, the rotational accuracy of the spindle must be made high Mi degrees.

That is, a rotating body such as a spindle provided with this polyhedral mirror is required to rotate at high speed and to have high rotation accuracy. For this reason, in the past, spindle bearings have been equipped with air bearing devices that support the spindle using a dynamic pressure effect, such as a herring-pond or tail-bearing type, for radial support, and magnetic bearing devices that use permanent magnets. is used for axial support.

By using these two bearings together, in addition to satisfying the above conditions, there are other advantages such as small torque loss and 711 torque loss.

Generally, the shape of the air groove of this air bearing is shown in Figure 3 (A).
It has a shape as shown in ~(C).

Machining of this air groove is a factor that determines the shaft support characteristics depending on the shape of the groove mouth body, 1M depth, etc., and extremely high precision is required.For example, in Fig. 3 (A) groove 1
11Q is a little less than 2mm, pitch is a little less than 2mm, and the shape accuracy is ±
Within 201gmJ, depth 1,000,015m m, accuracy is ±31gmJ (within tUX, ±2 [μmJ
) or less.

Moreover, not only are any of them within the tolerance, but also (
19 with +1 is desirable. Furthermore, since it rotates at high speed, the edges of its shape may be crisp.

The presence of sauce will affect its performance by 1αi5 and 7i.

How to pressurize unused Photo etching method 2) Rolling method 3) Grinding Kaloe method etc., but their main points and drawbacks are as follows.

l) Photoetching method Since the workpiece is cylindrical, when masking is performed along the circumference, misalignment as shown in FIG. 6 is likely to occur. Managing this deviation within ±20 LgmJ is difficult and extremely unproductive.

Moreover, if the shape is a Herringhorn as shown in FIG. 3 (AJ), the alignment of the fins will be difficult.

2) Is the productivity of the rolling method high? Because the rolling ties are pushed in and pressurized, plastic deformation creates a bulge as shown in Figure 7 (61)
If this occurs, it must be removed by centerless grinding, etc., and burrs may occur, and it becomes difficult to obtain viscosity due to centerless. Also, Tare rt (62
) also varies depending on the loft of the material and heat treatment conditions, making it difficult to obtain uniform shape accuracy.

3) Grinding method - It is easy to obtain shape accuracy, but the index of the grinding machine L'j
IJlt, angular accuracy has low reproducibility and becomes specialized once the setup is removed.

Moreover, the herringbone shape as shown in FIG. 3(A) is limited to the shape shown in FIG.

Also, it inevitably ends up with sharp edges, making it difficult to get an a-uta-like performance.

[Objective of the Invention J] The present invention has been made in view of the problems of the prior art described above, and it is possible to manufacture an air IM with an adjustment accuracy of 1':6.

In addition, the purpose is to establish Fj) production technology for air groove machining.

"41! of the invention" In order to achieve the above-mentioned objective 1, the embodiments of the present invention are as follows:
a protrusion-shaped surface of an electrode having a protrusion shape corresponding to the grooved shape of an air bearing that pivotally supports a rotating body by air pressure;
Step 4: Aligning the blade surface of the air bearing so that it is in a predetermined position; Step 5: In step 5, the machining position of the air bearing's machined surface and the protrusion-shaped surface of the electrode are maintained at a predetermined discharge gap. , along with electrical discharge machining, the release tt! ,/Jl
This process consists of a grooving step 1 in which the + ball position is rotated along the 710 plane of the air bearing to form the groove, and a separation step in which the electrode is separated from the air bearing after the grooving in this step is completed.

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the configuration of electrodes for forming air grooves in an air bearing using a dynamic pressure effect according to an embodiment of the present invention. In the figure, 1 is an electrode A, 2 is a spacer, 3 is an electrode 8iB,
4 is an electrode holder.

Figure 7JI11 shows an example of the structure of the electrode when forming the air groove shown in Figure 3 (C), and the electrode A1 is 3 in Figure 3 (C).
The electrode B3 has a protrusion shape corresponding to the air groove shown in FIG. 1, and the protrusion shape shown in 32 in FIG. These electrodes can be made by combining arbitrary electrodes depending on the shape of the air groove to be processed and inserting and fixing them into the electrode holter 4. For example, if the lead angle, width, and pitch of each air groove in Figures 753 (A), (13), and (C) are constant, one electrode can be used for machining various shapes of air 11 in combination. can.

For this reason, a convenient electrode spacer (2
Figure 3 (A) can be easily achieved by simply changing the presence or absence of a matchmaker in ).
Air grooves shown in can be machined.

In this example, the electrode material is CuW.

Using Cu, AgW, etc., a predetermined number of protrusions having a force 01 surface shaped like an air groove of an air bearing are created at a predetermined position using an NC lathe. For this reason, the control information fM such as the 8i combination and the sovereign material is recorded on a tape or the like, and the lathe operation can be performed 1ljlσ in accordance with the recorded information.

In addition, the 7718IA l, the electrode B3, and the spacer 2 are placed in the electrode holter 4 with a set screw 4a and a drop-off portion 1a.

It is centered and fixed by 2a and 3a.

Using such an electrode, the air 11 of the air bearing can be
For example, one hand is as follows.

First, a predetermined number of pressurized shafts 6 to be air grooved are set in the shaft holter jig 5L as shown in FIG. This shaft holder X5 is fixed to an unillustrated NG control grating, and swings as will be described later.

Next, the electrode holter 4 with the electrode set thereon is positioned at the position of the shaft 6 to be machined by a positioning/lowering means (not shown), and lowered to a predetermined position. An example of this state is shown in Figure 4 (A
), the electrodes Al, B3, and spacer 2 shown in FIG. 1 are installed in the electrode holder 4 when the air groove shown in FIG. 3(C) is installed. Then, depending on the depth of the air groove, set the discharge gap shown in FIG. Then, rotate eccentrically (shake once) as shown by arrow B in Fig. 4 (CB). At this time, set the discharge current according to the surface roughness of the air 114 to increase the discharge power.

In this way, in this embodiment, the NC discharge oscillation machining is performed with zero, so the depth of the air groove can be arbitrarily set depending on the amount of oscillation and the discharge current, and the reproducibility is high. Further, the roughness of one surface can be arbitrarily set depending on the discharge conditions. For example, the surface roughness can be improved by reducing the discharge #11fl. Furthermore, since the depth is approximately 20 E .mu.m, the processing time can be shortened compared to a processing method using etching.

In addition, since it is electrical discharge machining, air groove machining can be performed in the final process, and there is little sag, and unlike grinding power loe, there is no raised part, so high dynamic pressure characteristics can be obtained.

The electrode holter 4 that has completed the predetermined swinging process for a predetermined time is
It rises above the machined shaft, positions it at a predetermined position on the next pressurized shaft, and descends to perform the next electrical discharge machining.

In the following explanation, only one type of electrode holter 4 has been explained, but by being equipped with an auto tool changer and making it possible to change the electrode according to the air groove machining shape of the shaft to be machined, it is possible to use the same shaft holter jig 5. Various types of air groove shapes can be processed within the machine.

Further, the addition of shafts having various groove depths can be done arbitrarily by changing the setting of the swing end of each electrode holter 4.

Further, in the above explanation, the air groove machining on the sleeve of the air bearing was explained, but the present embodiment is not limited to this. , It is possible to machine the desired air grooves on the bearing side instead of on the shaft side.

In addition, by applying this addition method, it is possible to
Of course, it is also possible to do this by a craftsman.

As explained above, according to this embodiment, the mass production effect is good.
Can perform air groove machining for air bearings with high machining accuracy.

In addition, in this example, since the discharge is started after the electrode and the workpiece have been completely positioned, uneven wear of the electrode, which occurs in the conventional machining method of lowering and positioning while discharging, is eliminated, resulting in uniform wear. This allows the machining accuracy to be maintained at a uniform and high level of precision.

Furthermore, even if the workpiece is oscillated as in the example during discharge,
Furthermore, the same effect can be obtained by swinging the turret 44i side.

Furthermore, by setting the discharge gap between the electrode and the wave power work piece arbitrarily, it is possible to easily form an air groove of any depth and shape.

"Effects of the Invention" As explained above, according to the present invention, it is possible to process air grooves in air bearings with high precision and high mass production efficiency.
Ru.

In addition, it can be easily applied not only to hydrodynamic bearings but also to static pressure bearings.
A force Loe method for air II in an air bearing after f can be provided.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a machining electrode according to an embodiment of the present invention, Fig. 2 is an external view of a processing jig of this embodiment, and Fig. 753 (A)
~(,C) is a diagram showing the air groove shape of the air bearing. Figures 4 (A) and CB) are diagrams explaining the air groove processing of this embodiment, Figure 5 is a configuration diagram of other electrodes related to the present invention 1jJl, and Figure 6 is the busking using the conventional photoetching method. A diagram showing an example, FIG. 7 is a diagram showing a state under air 11η force I+ due to conventional rolling properties. In the figure, 1.3...electrode, 2...spacer, 4...
'III pole holter, 5... shaft holter jig, 6... shaft to be machined, 31.32... air groove. Figure 3 (△) (B) (C) 15 5 4th prisoner (A) Figure 4 (B)

Claims (2)

[Claims] (1) Alignment process in which the protrusion-shaped surface of an electrode having a protrusion shape corresponding to the groove-machined shape of an air bearing that pivotally supports a rotating body by air pressure is aligned so that the machined surface of the air bearing is in a predetermined position. Following this step, electric discharge machining is performed while maintaining the machining position of the machined surface of the air bearing and the protrusion-shaped surface of the electrode at a predetermined discharge gap, and the electric discharge machining position is rotated along the machined surface of the air bearing. 1. A method for machining air grooves in an air bearing, the method comprising: a groove machining step for machining grooves using the grooves; and a separation step for separating the electrode from the air bearing after the groove machining is completed. (2) Claim 1 characterized in that the discharge gap and discharge time can be changed depending on the depth of the groove machining shape.
2. Method of machining air grooves in air bearings as described in .