JPS6128097Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a thrust fluid bearing used in a high-precision rotating spindle.

Thrust fluid bearings conventionally used in audio equipment, video equipment, etc. have a cylindrical peripheral wall with a circular hole, as shown in FIG.
The support member 3a has a bottom wall that is open at one end and has a bottom surface 31a at the other end, and a shaft 2a rotatably supported by the support member 3a via an arbitrary radial bearing part. On the bottom surface 31a of the wall,
A bearing member 1a whose both end surfaces are planar is mounted, and in order to reduce the starting torque of the shaft 2a, a bearing member 1a is formed at the axial center position (center) of the shaft 2a. A sphere 5a is held in the blind hole 4a, and the bearing surface 11 of the mutually opposing end surfaces of the shaft 2a and the bearing surface 11a of the bearing member 1a is
a is provided with a groove for generating dynamic pressure, and a fluid such as oil, grease, water, or gas is interposed between the two as a lubricant, and pressure is generated by rotation of the shaft 2a to support the shaft 2a. It's getting old.

In general, the load capacity of this type of thrust bearing increases as the thickness of the lubricating oil becomes thinner, so in order to increase the load capacity of the bearing, it is necessary to make the film as thin as possible. It is necessary to precisely control the size of the slight protrusion of the sphere 5a held on the bearing surface 11a of the bearing member 1a from the bearing surface 11a so that the end face of the sphere does not contact the sphere. hole 4
Since a is a blind hole, it is difficult to precisely shape the depth of the hole, and as a result, errors are likely to occur in the amount of protrusion of the sphere 5a, and the axis line O- of the end surface of the shaft 2a The perpendicularity to O' is also a characteristic that tends to cause errors during molding, and thinning the thickness of the film often causes problems such as uneven contact. It has the disadvantage that it tends to significantly increase costs because it requires extra man-hours for molding.

This invention compensates for the above-mentioned drawbacks of conventional products and provides a fluid thrust bearing with high load capacity and low cost.

Next, a typical embodiment of the thrust bearing device according to this invention shown in FIG. 2 and FIG. 1 is a bearing member, 11 is a bearing surface of the bearing member 1, 2 is a shaft rotatably supported in a circular hole of the support member to be described later, 21 is an end surface of the shaft 2, and 3 is a cylindrical peripheral wall. 4 is a through hole, and 5 is a sphere.

Similar to FIG. 1, the bearing surface 11 of the flat bearing member 1 placed on the bottom surface 31 of the support member 3 and supported in the axial direction has grooves for generating dynamic pressure. The shaft 2 is supported by generating pressure in the lubricant interposed between the two, but unlike in FIG. Hole 4 is a through hole,
A sphere 5 having a diameter slightly larger than the thickness of the bearing member 1 is press-fitted into the through hole 4, and the outer diameter of the sphere 5 is slightly convex than the bearing surface 11 as in FIG. It is becoming a state. That is,
The top of the sphere 5 protrudes above the bottom surface 31 of the bearing member 3 by the difference between the thickness of the bearing member 3 and the diameter of the sphere 5.

As mentioned above, the conventional product has a hole 4 that holds the sphere 5a.
Since the hole a was a blind hole, it was difficult to accurately form the depth of the hole, and as a result, the spherical body 5
However, in the bearing member 1 according to this invention, the hole 4 that holds the sphere 5 is a through hole, so the depth of the bearing member 1 is determined by the depth of the blind hole 4a. It is sufficient to precisely form the thickness of 1, and forming to ensure the accuracy of the thickness of a flat plate member is much easier than forming accurately the depth dimension of a blind hole. Since the amount of protrusion of the sphere 5 can be formed stably with high precision, there is no risk that the shaft end surface 21 will come into contact with the sphere 5 during rotation even if the thickness of the lubricant is thinned, and the sphere Since the bearing 5 is press-fitted into the through hole 4, there is no fear that the lubricant will leak from the hole 4 even if the pressure increases, so it is possible to increase the thrust load capacity of the bearing.

FIG. 3 shows a second embodiment of the fluid thrust bearing device according to this invention, and unlike FIG. 2, the supporting surface, which is the end surface opposite to the bearing surface 11 of the bearing member 1, is formed in a spherical shape. The contact with the bottom surface of the support member 3 is centered around the apex of the spherical surface of the press-fitted sphere 5 on the side opposite to the convex side. Because there are
Even if the end surface 21 of the shaft 2 does not have an accurate perpendicularity to the center line O-O' of the shaft 2 and there is some error, the spherical shape on the opposite side of the bearing surface 11 of the bearing member 1 Due to the alignment of the support surface, the end surface 21 of the shaft 2a and the bearing surface 11 of the bearing member 1 are always kept parallel, even if the lubricant film formed between them is thin. The bearing surface 11 and the shaft end surface 2
There is no risk of damage or abnormal wear caused by uneven contact between the lubricating oil and the lubricating oil, and since the lubricating oil can be used thinner than before, a higher load capacity can be obtained.

As described above, in the thrust bearing of this invention, a sphere having a diameter slightly larger than the thickness of the bearing member is fixed in the through hole formed at the axial center position (center part) of the bearing member, and The top of the sphere is formed to protrude beyond the bearing surface of the bearing member by the difference between the thickness of the member and the diameter of the sphere, so in mass production, the thrust bearing part with uniform precision can be used with high precision. It can be easily obtained without requiring any processing or materials, and due to its high accuracy, it is possible to obtain a higher thrust load capacity than before.
Also, there are almost no factors contributing to high costs.

In the second embodiment of this invention, the spherical surface on the opposite side of the bearing surface 11 of the bearing member 1 is supported by the flat surface of the support member 3, but the above-mentioned support member is not limited to this. It is also possible to support part or all of the spherical surface of the bearing member 1 using a concave spherical seat, and the hydrodynamic groove can also be supported by the end surface of the shaft 2 or the bearing surface 11 of the bearing member 1. It may be provided on both sides.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a conventional hydrodynamic thrust bearing device, and FIGS. 2 and 3 are sectional views of main parts of an embodiment of a thrust bearing device according to this invention. In the figure, numeral 1 is a bearing member, 2 is a shaft, 3 is a support member, 4 is a through hole, and 5 is a sphere.

Claims (1)

[Claims for Utility Model Registration] (1) A support member having a circular hole having a cylindrical peripheral wall, one of which is open, and the other of which has a bottom wall, is placed on the bottom surface of the bottom wall, and a bearing member having a sphere in its center; and a bearing member rotatably supported in the circular hole, one end surface of which is in contact with the sphere, and bearing surfaces or shafts of the bearing members facing each other. In a hydrodynamic thrust bearing device having a groove for generating dynamic pressure on one or both of the end faces, a through hole is provided at the axial center position of the bearing member, and the hole has a diameter slightly smaller than the thickness of the bearing member. A hydrodynamic thrust bearing device characterized in that a sphere with a large diameter is fixed, and the top of the sphere protrudes beyond the bearing surface of the bearing member by the difference between the thickness of the bearing member and the diameter of the sphere. (2) The hydrodynamic thrust bearing device according to claim 1 of the utility model registration claim, wherein the end surface of the bearing member opposite to the bearing surface is flat. (3) The dynamic pressure fluid shaft thrust bearing device according to claim 1 of the utility model registration, wherein the opposite side of the bearing surface of the bearing member is formed in a spherical shape.