JPS6331556B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for machining grooves in the shaft or receiving portion of a hydrodynamic bearing with grooves, and particularly to a method for machining required grooves in a cylindrical surface, a conical surface, or the like.

Conventionally, in machining grooves on the cylindrical or conical surface of the shaft of the grooved hydrodynamic bearing, a photographic plastic film or a metal plate, on which the desired groove pattern has been developed in a plane, is used as the surface to be machined. It was used as a photoetching mask by attaching it to a cylindrical or conical surface on which resist was formed, but due to the rigidity of the mask's constituent material,
It has been difficult to improve adhesion to the surface to be processed at the joints of the mask. If this adhesion is poor, during exposure, light will enter through the gap between the mask and the resist surface, irradiating areas that do not need to be exposed, and as a result, the desired groove shape will be distorted during the etching process. There were cases where it was not possible to obtain the groove shape as expected.

This invention was made in order to eliminate the above-mentioned drawbacks, and is a method for processing a hydrodynamic bearing with grooves, in which a resist is formed on the processing surface of a workpiece, and a desired groove pattern is formed by planar development. A planar mask made of a film or metal plate is attached to the surface to be processed on which the resist is formed, and then a contact jig that has a shape corresponding to the surface to be processed, allows the exposure light to pass through, and has elasticity is attached. , by attaching it to the flat mask, the flat mask and the resist surface on the surface to be processed are brought into close contact, and in this close contact state, the necessary areas are exposed to light. When the exposure is completed, the contact jig and the flat mask are attached to the flat mask. This is a method of processing a grooved hydrodynamic bearing in which a mask is removed and required grooves are formed on the surface to be processed by etching.

Next, a first embodiment of the present invention will be described. The first embodiment is a case where a required groove is formed on a cylindrical surface which is a processed surface of a grooved hydrodynamic bearing, and 1 is a flat mask made of a film in which a groove pattern 11 of a desired shape is developed in a plane. FIG. 2 shows the flat mask 1 rolled up into a cylindrical shape and the seam 1
2 and held together with tape. The size of the diameter of the cylinder of this flat mask 1 is determined according to the outer diameter dimension of the shaft 2 to be processed, and in actual groove processing, the shaft 2 to be processed on which the resist 21 has been formed is
The flat mask 1 may be wrapped around the mask 1 and the seam 12 may be secured with a suitable adhesive tape. Reference numeral 10 denotes a flat mask having a seam 102 different from that of the flat mask 1 described above, and the seam 102 is shaped like an inequality sign to prevent it from shifting in the axial direction when attached to a workpiece. FIG. 3 shows a cap 3 as an adhesion jig made of a material that allows exposure light to pass through, for example, transparent acrylic, and its inner diameter is determined by the outer diameter of the shaft 2 to be processed and the thickness of the flat mask 1. The decision will be made taking into account the following. That is, the inner diameter of the cap 3 before installation is made slightly smaller than the diameter of the shaft 2 to be processed, which is coated with a resist 21 and wrapped with a flat mask, so that the mask 1 can be brought into close contact with the shaft 2 to be processed. There is.

In order to form grooves on the shaft 2 to be processed using the flat mask 1 and the cap 3 as a contact jig, a resist having a uniform thickness is formed in advance on the processing surface of the shaft 2 to be processed.

Next, a flat mask 1 rounded into a cylindrical shape as shown in FIG. 2 is attached to the processing surface of the shaft 2 to be processed. The wearing of this flat mask 1 is as described above.
The planar mask 1 may be wrapped around the shaft 2 to be processed, and the joint may be fixed with a suitable adhesive tape as necessary to prevent the groove pattern 11 from shifting.

In the next step, a cap 3 made of transparent acrylic and serving as a fitting jig is placed over the flat mask 1.
At this time, the seam 12 of the plane mask 1 and the cut 31 of the transparent acrylic cap 3 should not coincide with each other. With the planar mask 1 firmly brought into close contact with the shaft 2 to be processed by the cap 3 in this manner, the process proceeds to the exposure step in the photoetching process. When the exposure of the required portion of the shaft 2 to be processed is completed, the cap 3 and the flat mask 1 are removed. Next, in an etching process, required grooves are formed, and the resist is further removed, thereby completing the machining process and obtaining a processed shaft having the required grooves.

The second embodiment shown below is a case where required grooves are formed on the conical surface of the shaft of a grooved hydrodynamic bearing. The planar mask 4 is shown formed into a conical shape and its seam 42 is fixed with an adhesive tape 43. Needless to say, the dimensions of the film need to be adjusted according to the conical angle and diameter of the shaft 5 to be processed so that the conical shape is in close contact with the conical surface 51 of the shaft 5 to be processed. FIG. 6 shows a cap 6 as a fitting jig made of a material that passes the exposure light and is placed over the flat mask 4. If it has appropriate elasticity, it may have a seam, or it may have a diameter of an appropriate size. It may be made by processing the inner surface of a transparent solid material having dimensions to match the conical surface 51 and dimensions of the shaft 5 to be processed. Alternatively, the cap with the desired conical inner surface may be molded from a plastic material through which the exposure beam passes.

In this second embodiment as well, a resist 52 is formed on the surface of the shaft 5 to be processed as in the first embodiment. Next, the conical plane mask 4 is placed on the conical surface 51 of the shaft 5 to be processed on which the resist 52 is formed.
By covering the cap 6 with the cap 6, the flat mask 4 is completely brought into close contact with the conical surface 51 on which the resist 52 is formed. With the planar mask 4 in close contact with each other in this manner, exposure as used in normal etching processing is carried out. After the necessary portions have been exposed, the cap 6 and the flat mask 4 are removed, and the next step is an etching process. A required groove is formed by this etching process. In the next step, the resist is removed and the processing is completed.

In both of the above two embodiments, the photomask used was a flat mask made of plastic film used for photography, but this photomask could be, for example, a metal plate with the required groove pattern developed. may be used.
This metal plate is preferably made of a material that has low rigidity and easily conforms to the machined surface of the workpiece.

Further, in the above embodiments, the surface to be processed is a cylindrical outer surface or a conical outer surface, but the processing method of the present invention can also be applied to a cylindrical inner surface or a conical inner surface. For example, if the surface to be processed is the inner surface of a cylinder, a flat mask with the required grooves developed in a plane is attached to the inner surface of the cylinder, and then the mask is made of a material that allows the exposure light to pass through, so that the mask can be pressurized from the inside. Using a fitting jig that has a suitable elasticity and an outer diameter slightly larger than the inner diameter of the mask in the free state, the mask is pressurized and tightly attached to the inner surface of the cylinder, which is the surface to be processed. Through a detailed etching process, the necessary grooves can be created.

According to the processing method of the present invention, the flat mask made of film or metal plate used as a photomask is reliably brought into close contact with the surface to be processed by using the contact jig, so that only necessary areas are exposed during the exposure process. This allows for accurate groove machining. Therefore, it is possible to obtain a grooved hydrodynamic bearing with an accurate shape.

[Brief explanation of the drawing]

1 to 4 relate to a first embodiment of the present invention, and FIGS. 1a and 1b are plan views of a film flat mask having a groove pattern developed in a plane for use in a photomask, respectively; Figures 2a and 2b are perspective views of the planar mask shown in Figure 1 formed into a cylindrical shape to fit the surface to be processed, respectively, and Figure 3 is a perspective view of a cap made of material through which the exposure light beam passes. , FIG. 4 is a partially longitudinal sectional explanatory view when the above-mentioned plane mask and cap are attached to the shaft to be processed, and FIGS.
FIG. 5 is a perspective view of a conical film flat mask having a desired groove pattern, FIG. 6 is a perspective view of a cap made of a material that allows exposure light to pass through, and FIG. The figure is an explanatory view, partially in longitudinal section, when the above-mentioned flat film mask and cap are attached to a shaft to be processed having a conical surface. Explanation of symbols 1, 4, 10 are plane masks, 2,
5 is the shaft to be machined, 3 and 6 are the caps.

Claims (1)

[Claims] 1. A step of forming a resist on the surface to be processed of the workpiece, and applying a planar mask formed by developing a required groove pattern on a plane in advance using a contact jig having a shape corresponding to the surface to be processed. A step of bringing the planar mask into close contact with the formed surface to be processed, a step of exposing the planar mask to light while keeping it in close contact with the surface to be processed, and after completion of the exposure, removing the adhesion jig and the planar mask, and performing etching. A method for processing a grooved hydrodynamic bearing, which comprises the step of forming a required groove.