JPS634517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is a method for printing a cylindrical outer circumferential surface, which is used when printing a special shape on the outer circumferential surface of a shaft body, as a process of forming hydrodynamic grooves for a hydrodynamic bearing shaft body. It concerns method improvements.

Generally, when printing a desired shape on the outer circumferential surface of a cylindrical object, the shape tends to be distorted due to overlapping printing at the seam of printing after one rotation. For example, as shown in FIG. 1, the shaft body of a hydrodynamic bearing with dynamic pressure generating grooves is provided with curved dynamic pressure generating grooves 2a, 2a, etc. on the outer peripheral surface of a cylindrical shaft body 1a. However, the shape of the groove is special,
Since it is mechanically difficult to form, conventionally the shape of the non-formed part around the groove is baked onto the outer circumferential surface of the cylindrical shaft body 1a by a photoetching method that applies optical technology. Either the shaft 1a is corroded by etching to form hydrodynamic grooves, or the shaft 1a is rotated once while in contact with a printing mold of a special printing device, and the non-formed portion is coated with corrosion-resistant ink on the outer peripheral surface of the shaft 1a. There are methods such as printing the shape and forming it by etching as mentioned above, but the former involves a large number of steps, is complicated and difficult to rationalize, and the latter is highly efficient, but As mentioned above, this method has the disadvantage that the shape of the groove is easily distorted due to overlapping of insufficiently cured ink at the printing joint, and the shape often needs to be corrected after printing, so it is not yet in practical use. do not have.

This invention compensates for the above-mentioned drawbacks of the conventional methods, and has no insufficiently cured parts in the printing joints, so there is no need to modify the shape, and the quality is stable. It provides:

Next, a method of printing a shape around a herringbone groove of a shaft body for a hydrodynamic bearing, which is a typical example of the printing method according to the present invention shown in FIGS. 2 and 3, will be explained. It is an explanatory diagram showing the order of printing, and in the diagram, reference numeral 1 indicates a shaft body, and 2
is the preceding printing part that becomes the printing joint, 3 is the desired 2
This is the second printing department.

First, to explain Figure 2, the figure shows the shape of the non-formed part around the groove that forms the herringbone groove for generating dynamic pressure. This is an external view showing a printed state, in which a part of the shape is printed in a narrow width on the outer peripheral surface of the shaft body 1 as a pre-printed part 2.

Figure 3 shows a state in which the shaft 1 is rotated once using a special printing mold with a desired shape around the groove, and printing is stopped just before it returns to its original position. A second printing section 3 is shown in which a portion corresponding to the preceding printing section 2, which is a joint portion, is missing.

In this invention, the desired shape around the groove is printed by the printing order shown in FIGS. 2 and 3. At an arbitrary position, the narrow part of the desired shape to be printed is printed linearly in the axial direction as a pre-printed part 2 to form a joint part, and then a desired groove is printed using the pre-printed part 2 as a base point. The shaft body 1 is brought into contact with a special shaped printing mold and rotated once, and a second printing section 3 is printed by slightly overlapping the printing on the preceding printing section 2.

According to this method, the ink in the preceding printing section 2, which becomes the printing joint, has already hardened, so even if the printing of the second printing section 3 overlaps the preceding section 2, the uncured ink will overlap. There is no distortion of the shape around the grooves caused by the bonding of the grooves, and there is no need to modify the shape after printing, which was conventionally done, and printing with a stable shape can be ensured.

Although this embodiment shows a case in which the shape of the outer circumferential surface of the shaft body having herringbone grooves for generating dynamic pressure is a cylindrical surface, the shape of the outer circumferential surface of the shaft body 1 is not limited to this. Even if the surface is a conical surface, it can be carried out in almost the same way by changing the device.

[Brief explanation of the drawing]

FIG. 1 is an external view of a conventionally used hydrodynamic bearing shaft with grooves for generating dynamic pressure, and FIGS. 2 and 3 are explanatory diagrams showing the printing order according to the present invention. In the figure, numeral 1 is a shaft, 2 is a preceding printing section, and 3 is a second printing section.

Claims (1)

[Scope of Claims] 1. Supply ink to a printing mold of a desired shape, and rotate the outer peripheral surface of a cylindrical object once while contacting the printing mold to join the printing, completing printing of the desired shape. In the printing method for a cylindrical object, a part of the desired shape to be printed on the outer peripheral surface in the circumferential direction,
The entire length or a part of the axial direction is preprinted in advance to cure the ink, and then the remaining part is printed by rotation using the preprinted location as a base point, so that the uncured ink joins at the printed joint. A method for printing a cylindrical outer circumferential surface, characterized in that the deformation of the shape that occurs as a result of this is prevented. 2. A method of printing a cylindrical outer circumferential surface according to claim 1, wherein the desired printing shape is a non-molded portion around a herringbone groove of a fluid bearing.