JPS61130490A - Formation of dynamic pressure generation groove - Google Patents

Abstract

PURPOSE:To form stable and inexpensive dynamic pressure generating grooves with high accuracy in a titled method for forming a shaft body for a fluid bearing by exposing the shaft body and cylindrical mask while turning integrally the shaft body and mask then etching the same after exposure thereof. CONSTITUTION:The cylindrical outside peripheral part of the cylindrical shaft body 2 is covered by the cylindrical mask 12 formed with the shape 11 of the desired dynamic pressure generating grooves (herringbone grooves in this embodiment). The outside diameter in the cylindrical direction of the body 2 is ground to high accuracy of about 3-5mu tolerance. The inside diameter of the mask 12 is larger by about 10-20mu than the outside diameter of the shaft body 2 and the shaft body 2 can be freely put into and out of the mask 12 inside. The mask 12 and the shaft body 2 are fixed by an adhesive cellulophane tape, etc., and both are integrally rotated one turn by means of a motor, etc. The light form a light source 14 for exposing above both passes the shape 11 and sensitizes the photoresist coated on the cylindrical outside peripheral surface of the body 2. The part of the body 2 except the shape 11 is masked by the photoresist and the dynamic pressure generating grooves 4 are formed by a method such as etching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a method for forming dynamic pressure generating grooves in a shaft body for a fluid bearing.

[Conventional technology]

Conventionally, the dynamic pressure generating groove of a shaft body for a hydrodynamic bearing has been formed as described below.

For example, as shown in FIG. 4, the cylindrical outer peripheral surface pressure of the shaft body 2 having a cylindrical shape is called Hering? - shaped dynamic pressure generating groove 4
When it was desired to provide a groove, the method shown in FIG. 5 was used to form the groove. That is, as shown in the figure, the cylindrical shaft body 2 is rotatably supported by two rotatable support rollers 6 in the direction into the figure. Further, two rotatable photographic film pressing rollers 8 are pressed against the shaft 2, and a photographic film mask 10 is held between the photographic film pressing rollers 8 and the shaft 2. The photographic film mask IOK has two rows of desired dynamic pressure generating grooves 11 (herring-shaped in this case) to be formed in the shaft body 2. A photoresist is applied to the cylindrical outer circumference of the shaft body 2, and as the shaft body 2 rotates, a photographic film mask 10 is formed.
moves in direction B. Light is irradiated between the two photographic film pressing rollers 8 from an exposure light source 14, and the shape of the desired dynamic pressure generating groove 11 formed on the photographic film mask 10 is
The light flux that has passed through exposes the photoresist coated on the shaft body 2. By masking and etching the shaft 2t-7 with an photoresist, dynamic pressure generating grooves 4 are formed in the shaft 2 as shown in FIG.

[Problem that the invention seeks to solve]

However, when the method described above is carried out, the photographic film mask 10 is held between the shaft 2 and the photographic film pressing roller 8 by the frictional force, so the photographic film mask 1O slips in the circumferential direction of the shaft 2. In case of misalignment, the photographic film mask 10 may also be misaligned in the axial direction of the shaft body 2.
In some cases, the desired dynamic pressure generating groove shape 11 is not formed on the outer circumference of the shaft body 2. For this reason, all corrections are made with photoresist, but even if the corrections are made, Herring♂
- Distortion of the shape of the groove may remain.

Therefore, even if the shaft body 2t having the dynamic pressure generating groove 4t is mass-produced by such a method, the characteristics of the dynamic pressure generating groove 4 are poor, and many of the manufactured products are defective. It had many drawbacks, including high cost.

〔the purpose〕

SUMMARY OF THE INVENTION In order to eliminate the drawbacks of the above-mentioned conventional examples, the present invention provides a highly accurate, stable quality, and inexpensive method for forming dynamic pressure generating grooves.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention fixes a cylindrical mask in which a desired dynamic pressure generating groove shape is formed around a cylindrical shaft whose outer periphery is coated with 7 Otoresist, and Dynamic pressure generating grooves are formed on the outer circumferential portion of the shaft body by punching and cutting exposed while rotating integrally with the cylindrical mask.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the method for forming dynamic pressure generating grooves according to the present invention will be described in detail below with reference to the drawings.

Fig. 1 shows a method of forming a dynamic pressure generating groove according to the present invention. A ring-groove shape 11 is formed and covered by a cylindrical mask 12. The outer diameter of the shaft body 2 in the cylindrical direction has a tolerance of 3 to 5μ.
It is ground with a high precision of m. And cylindrical mask 1
The inner diameter of the shaft body 2 is also 10 to 20 ttm larger than the outer diameter of the shaft body 2, and the shaft body 2tj can be freely inserted into and taken out of the cylindrical mask 12. As for the method of fixing the cylindrical mask 2 and the shaft body 2, they may be fixed with cellophane tape or the like, or a mounting tool shown in FIG. 3 may be provided as described later.

FIG. 2 is a cross-sectional view of an apparatus for actually exposing the shaft body and cylindrical mask shown in FIG. 1. As shown in the figure, the shaft body 2 covered by the cylindrical mask 12 is fixed to the cylindrical mask 12 with cellophane tape or the like and rotated as one unit by the driving force of a motor (not shown) or the like. At that time, the light emitted from the exposure light source 14 provided above the shaft body 2 and the cylindrical mask 12 passes through the slit plate 16 for exposure.
The photoresist coated on the cylindrical outer peripheral surface of the shaft body 2 is exposed and exposed to light as it passes through the desired dynamic pressure generating groove shape 11 formed in the cylindrical mask 12.

Dynamic pressure generating grooves 4 are then formed on the shaft body 2 by masking the portions other than the desired dynamic pressure generating groove shape 11 with a 7-photoresist, etching, or other methods.

Incidentally, the cylindrical mask 12 can be vibrated by using a photographic film in which a desired dynamic pressure generating groove shape 11 is formed and pasting the cylindrical joint portion with a transparent adhesive or the like.

Fig. 3 is a longitudinal cross-sectional view of the shaft body when fixing the shaft body and the cylindrical mask using a substitute K such as cellophane tape and a fixture for fixing the cylindrical mask and the shaft body. .

As shown in the figure, one end of the shaft body 2 (provided/IJ
The shaft body 2 and the cylindrical mask 12 are fixed by a fixture 18 that fixes the cylindrical mask and the shaft body, which are made of cardenate resin or polyastal resin, and can rotate together. Further, a shaft mounting tool 20 for supporting the shaft is provided at the other end of the shaft 2.

In addition, as another method for producing a cylindrical mask, without using a photographic film mask, desired dynamic pressure generating grooves are press-processed in advance on aluminum or stainless steel foil (thickness 0.1 to 0.01 vex). There is also a method of making a cylindrical mask by opening the mask by cutting or electrical discharge machining, bonding it to a transparent polyester sheet, etc., and bonding the joints with an adhesive or the like. In that case, use a positive resist to apply the resist to the shaft, expose the desired shape of the dynamic pressure generation groove on the cylindrical outer circumference of the shaft, and mask the parts other than the dynamic pressure generation groove with the resist. In particular, dynamic pressure generating grooves are formed.

〔Effect of the invention〕

As described above in detail and specifically, according to the present invention, since the shaft is inserted into the cylindrical mask and both rotate together, the umbrella part is misaligned on the cylindrical outer peripheral surface of the shaft. The desired dynamic pressure generating groove is formed without any trouble, and as before,
There is no need to modify the joint using resist, making it possible to form hydrodynamic grooves with high precision, high quality, stability, and low cost.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the shaft and cylindrical mask, Figure 2 is a sectional view of the apparatus used to actually expose the shaft and cylindrical mask shown in Figure 1, and Figure 3 is the shaft and cylindrical mask. FIG. 3 is a cross-sectional view of a case where a fixture for fixing a cylindrical mask and a shaft body is provided in order to fix the mask. Figure 4 shows the generation of Hering-Zehne-shaped dynamic pressure on the outer circumferential surface of the cylinder.
FIG. 5 is a perspective view of a forming apparatus for a conventional method of forming dynamic pressure generating grooves. 2... Shaft body, 4... Dynamic pressure generating groove, 11... Light source,
12...Cylindrical mask. Agent Patent Attorney Jo Taira Yamashita Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A cylindrical mask in which a desired dynamic pressure generating groove shape is formed is fixed around a cylindrical shaft whose outer periphery is coated with photoresist, and the shaft and the cylindrical mask are integrated. 1. A method for forming a dynamic pressure generating groove, which comprises forming a dynamic pressure generating groove on the outer circumferential portion of the shaft body by etching after exposure while rotating the shaft body.