JPS6049770B2 - Manufacturing method of hemispherical spiral grooved rotating shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a rotating shaft having a required spiral groove on the surface of a hemisphere.

The spherical spiral grooved rotating shaft has a spiral groove on its surface, and generates pressure in the fluid by rotating in the fluid within the four slopes corresponding to the spherical surface, and floats on itself. There are various shapes depending on the required performance. One type of spherical spiral grooved rotating shaft that is required to rotate stably at high speed is a hemispherical spiral grooved rotating shaft. In order to rotate stably at high speed, it is necessary to ensure that fluid exists in the bearing gap between the spherical surface of the rotating shaft and the bearing surface, and this type of rotating shaft meets this type of requirement. I can do it. In other words, the flow of fluid into the bearing gap becomes smoother, and performance can be controlled by cutting the latitude height of the hemisphere to match the required performance.
It becomes possible. In such a rotation axis, it is important to accurately finish the latitude of the hemisphere and its surface roughness. 1st
The figure shows an example of a spherical spiral grooved bearing, where 1 is a shaft connected to the drive shaft, 2 is a sphere provided at one end of the shaft 1, and 6
indicates the joint surface between the shaft 1 and the sphere 2. 3 indicates a spiral groove that is relatively shallowly machined on the spherical surface, 4 is a receiving part with a four-spherical surface, and 5 is a gap in the bearing, and during operation, this gap is filled with fluid. .

In this type of bearing, as the rotation speed increases, the ball 2 of the shaft 1
The centrifugal force on the surface increases, the fluid on the surface is blown away to the surroundings, and the flow into the gap 5 is reduced, causing an unstable phenomenon of the bearing and ultimately causing seizure. In order to improve such performance, the configuration of the rotating shaft shown in FIGS. 2 and 3 has been developed. That is, it has the structure shown in FIG. 2 in which the sphere 2 provided on the rotating shaft 1 in FIG. 1 is made into a hemisphere 21, and the relatively large chamfer 7 shown in FIG. This is the rotation axis 1 of the structure. This type of rotating shaft is usually manufactured as follows.

That is, a spherical or hemispherical part is manufactured at one end of the rotating shaft 1 by J-cutting or grinding, and then a required groove is formed in the spherical or hemispherical part by photo-etching. For a shaft with only a spherical part processed, the spherical part can be further processed into a hemisphere using grinding or turning, or the shaft and the spherical part can be made separately in advance and then welded or glued together. There is a method in which the spherical parts are joined by the above-mentioned method, the required grooves are formed on the spherical surface using the above-mentioned method, and then the spherical part is manufactured into a hemisphere by grinding or turning. However, this type of manufacturing method has the following drawbacks. In other words, the method of photo-etching a required groove on a spherical surface and then machining it into a hemisphere causes plastic deformation of the material of the spherical part during machining, resulting in C. It causes burrs on the second part. In this type of rotating shaft, the shape of the groove is expected to have a rectangular shape with a more accurate cross section, the better the performance will be, and the dimensions A, B, and C in FIGS. 2 and 3 also have a great effect on the bearing performance. Therefore, when removing the generated burrs, great care must be taken not to affect the rectangular shape of the groove and the A, B, and Cl dimensions, which requires the operator's skill and is time-consuming. It is also a factor that increases costs. Further, in the method of first performing hemispherical processing and then processing the grooves, the generated burrs can be easily removed, but there are many drawbacks that occur in the photo-etching process. That is, when applying a photosensitizer to a spherical surface,
As shown in FIG. 4, if the surface is spherical, the photosensitive agent coating 8 will have a substantially uniform thickness, and the hemispherical portion that exposes the groove pattern will have an even more uniform thickness, making it possible to copy the pattern with high precision. However, on the other hand, the photosensitive agent coating 8 on the hemisphere shown in FIG. All you get is a copy of a bad pattern. This invention was made in order to eliminate the above-mentioned drawbacks of this invention, and aims to provide a method for manufacturing a highly accurate hemispherical spiral-shaped, grooved rotary shaft. Either a separately produced sphere is joined to one end by means such as welding or gluing, or a sphere is made at one end of the shaft by cutting or grinding, and then a spiral groove is formed on the surface of the sphere. ,next! This is a method for manufacturing a rotating shaft with hemispherical spiral grooves, in which a shaft and a sphere are processed into a desired shape by electrolytic grinding.

Next, one embodiment of the present invention will be described with reference to the drawings.

First, the shaft and the sphere are manufactured separately, for example, in
As shown in Japanese Patent No. 142458, a concave spherical surface 11 having a radius of approximately \112 of the spherical diameter of the sphere 2 is machined on one end of the shaft 1 (see Fig. 6), and the sphere 2 is placed on this concave spherical surface 11. irradiate the part to be bonded with an electron beam while rotating while in close contact, or irradiate the part to be bonded with an electron beam while rotating the electron beam irradiation source around the part where the axis and the sphere are in close contact, The shaft 1 and the sphere 2 are joined. In the above example, the shaft and the sphere were manufactured separately and joined together, but as another method, the sphere may be provided at one end of the shaft by means such as cutting or grinding.

Next, as shown in FIG. 7, a required spiral groove 21 is formed on the surface of the sphere 2 by electrical discharge machining, or by photo-etching as shown in Japanese Patent Laid-Open No. 51-62153, A mask with the required size and the required number of holes in spiral grooves is made, this mask is placed over the sphere 2 coated with a photosensitizer in advance, and the mask is exposed by irradiating it with UV light rich in ultraviolet rays. After removal, a development process is performed to form a resist, and then the sphere is etched, and the resist is further removed to form a spiral groove. Once the spiral grooves have been formed on the spherical surface in this manner, the required portions are processed using an electrolytic grinding device as shown in FIG. Reference numeral 31 denotes an electromagnetic grinding wheel, and a voltage is applied between it and a center 32 by a power source 33, and an electrolytic solution 34 is injected between the shaft 1 and the workpiece consisting of the sphere 2 to carry out electrolytic grinding.

Reference numeral 35 indicates a reverse center, and the workpiece is centered as a rotating shaft by the center 32 and the reverse center 35, and is rotated at a relatively high speed by means such as cutting. By rotating the electromagnetic grinding wheel 31 and bringing the two closer together, the workpiece is electrolytically ground, that is, the cylindrical surface of the shaft 1 is machined so that the amount of eccentricity with respect to the shaft center 36 is as small as possible. The sphere 2 that is continuous with the cylindrical surface of the sphere 1 is processed until it reaches the required half size.

With this electrolytic grinding as the final step, a rotating shaft with a hemispherical spiral groove is completed. According to the manufacturing method of the present invention, even when the spiral groove is processed by photoetching, the photosensitive agent is applied in the form of a sphere, so the accumulation of the photosensitive agent as shown in FIG. 5 does not occur. Precise photo-etching is possible, and since the shaft and sphere are processed by electrolytic grinding, unlike pure mechanical grinding, no burrs are produced on the workpiece. Moreover, the processing pressure during processing is extremely low compared to general grinding or machining, and there is no heat generation, so there is almost no concern that processing distortion will occur. Furthermore, since the processing pressure during processing is low, there is no contact damage to the spherical part caused by the support center. Therefore, it is expected that the spirally grooved rotary shaft manufactured by the manufacturing method of the present invention will have extremely superior dimensional accuracy and shape compared to conventional bearings.

[Brief Description of the Drawings] Figures 1 to 3 each show a spiral grooved bearing, Figure 1 is a partially vertical front view of the bearing having a sphere at one end of the shaft, and Figure 2 is one end of the shaft. FIG. 3 is a partially vertical front view of a bearing having a hemisphere at one end of the shaft, and FIGS. The figures are partially vertical front views showing the case where a photosensitive agent is applied to the surfaces of a sphere and a hemisphere, respectively. Figures 6 to 8 show an embodiment of the present invention, and Figure 6 shows a shaft and a sphere. Fig. 7 is a front view of a sphere with a spiral groove machined into it, and Fig. 8 is a partial vertical cross-sectional front view of an apparatus for machining shafts and spheres by electrolytic machining. .

Claims (1)

[Claims] 1. In a method for manufacturing a rotating shaft with a hemispherical spiral groove, a sphere is formed at one end of the shaft, a required spiral groove is formed on the surface of the sphere, and then the rotating shaft with the spiral groove machined is A hemisphere characterized in that the shaft end is supported at the center and the spherical part is supported at the reverse center, and the cylindrical surface of the rotating shaft and the spherical part continuous to the cylindrical surface are electrolytically ground to process the spherical part into a hemisphere. A method for manufacturing a rotating shaft with a surface spiral groove.