JPS5825884B2 - Dynamic thrust bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrodynamic thrust bearing with a spiral groove that rotates in a fluid.

Conventionally, this type of bearing has, for example, a spherical convex surface 11 at the shaft end as shown in FIG. 1, and a plurality of spiral grooves 12 on the lower side of this spherical convex surface. It consists of a rotary member 1 and a bearing member 2 having a concave receiving surface 21 cooperating with the convex surface 11 of the rotary member 1 on the side opposite to the convex surface 11 of the rotary member 1, and the upper end 1 of the spiral groove.
3 are arranged in a straight line and positioned above the upper plane 22 of the concave receiving surface 2 by the dimension H in the figure.

It is known that the above dimension H has a large effect on the rotational performance of this type of bearing, and the inflow of fluid into the bearing gap is O<
It was stable in the range of H<δ (δ is a constant depending on the type of bearing), and became unstable when H>δ.

On the other hand, when H<0, the bearing is stable in a small circumferential speed range, but may become unstable when the rotation is fast and the circumferential speed becomes large.

When the flow of fluid into the bearing gap becomes unstable, the bearing is likely to seize due to fluctuations in the flying height or its sudden decrease, or whirl, such as wobbling of the rotating member, is likely to occur.

Furthermore, as the rotation of the bearing increases, the viscosity of the fluid changes due to the heat generated by the bearing, so the flying height decreases and the above H dimension changes, so it is important to maintain the optimal value of the H dimension at all rotation speeds. was extremely difficult.

This invention was made to eliminate the above-mentioned drawbacks, and in order to cope with changes in H dimension caused by changes in rotation, changes in fluid viscosity, etc., some of the spiral grooves are It is an object of the present invention to provide a dynamic pressure type thrust bearing configured such that the upper end position of a shaped groove can maintain an optimum dimension H.

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

3 is a rotating member having a spherical convex surface 31 on the lower side;
A plurality of spiral grooves 5 are formed on the convex surface 31.

The bearing member 4 corresponding to the rotating member 1 has the convex surface 31
A minute gap is formed between the bearing surface and the concave bearing surface 41 which cooperates with the convex bearing surface 31 to form a fluid bearing.

In this embodiment, the upper end positions of the spiral grooves 5 are formed every other line at a high position 51 and a low position 52, and when the rotating member 3 rotates at a high position, the low position 52 4 is designed to coincide with the upper plane 42 of 4 and the line where the optimum H dimension is maintained, and the high end position 51 is designed to be aligned with the upper plane 42 of the rotary member 4 to the extent that the rotating member 3 does not interfere with the rotation of the supporting member 4. In contrast, the lowest position is expected, and the end position is designed so that it is located at the optimal H-shape with the upper plane 42 of the support member 4 that is to be buttoned at this position.

The above-mentioned high and low positions are slightly different depending on the size of the bearing, and the figure is exaggerated.

FIG. 2 shows a case where the rotating member 3 is rotated at a low position, and the optimum H dimension is maintained between the high position 51 of the terminal position and the upper plane 42 of the support member 4.

On the other hand, when the rotating member 3 rotates at a high position, the lower end position 52 and the upper plane 42 of the support member 4 are at the optimum position H.
The dimensions will be maintained.

In the second embodiment shown below, the upper end position of the spiral groove 6 is sequentially changed, and the position relative to the support member during rotation of the rotating member 3 is scheduled to be low, middle, and high. The upper end positions of the spiral groove 6 are selected as a high position 61, a middle position 62, and a low position 63;
As designed, the actual difference is extremely small.

Also in this second embodiment, the rotating member 3 is connected to the supporting member 4.
When rotating at a high position, the end position of the spiral groove 6 is such that the low position 63 and the upper plane 42 of the support member 4 maintain the optimum H dimension, and the rotating member 3 is at a medium position. When the rotating member 3 rotates at a low position, the intermediate position 64 of the end position of the spiral groove 6 maintains the optimum H dimension with the upper plane 42, and when the rotating member 3 rotates at a low position, the spiral groove 6 The high position 61 of the end position of 6 maintains the optimum H-shape with the upper plane 42.

In the above embodiment, the end position of the spiral groove was explained in two types, high and low, or in three types, high, medium, and low.
It is also possible to use a type, and the order of height does not necessarily have to be set in a fixed order.

In the hydrodynamic thrust bearing of the invention described above, during rotation, a plurality of the spiral grooves always maintain the optimum H dimension, so that the inflow of fluid during bearing rotation is stable, and the rotating member is Fluctuations in the flying height and bearing temperature can be suppressed, and rotational performance can be greatly improved compared to conventional bearings of this type.

In the above embodiment, the rotating member has a spherical convex surface, and the supporting member has a concave receiving surface corresponding to the spherical convex surface. The shaped surface or concave receiving surface is not limited to a spherical shape, and even if the surface or receiving surface has a conical shape, the optimal H dimension can be maintained by providing a minute difference in the end position of the spiral groove. By measuring, the same effects as above can be expected.

[Brief explanation of drawings]

FIG. 1 is a partially vertical front view showing a conventional dynamic pressure type thrust spherical bearing, and FIGS. 2 and 3 are partially vertical front views showing an embodiment of the present invention. Explanation of symbols 1 is a rotating member, 2 is a support member, 12 is a spiral groove, H is an optimal dimension, h is a flying height, 3 is a rotating member, 4 is a support member, 42 is an upper plane, 5 is a spiral groove Groove, 51 is a position where the end position of the spiral groove is high;
52 is a low end position of the spiral groove, 6 is a spiral groove, 61 is a high end position of the spiral groove, 62 is a medium end position of the spiral groove, and 63 is a middle position. The end position of the spiral groove is low.

Claims (1)

[Claims] 1. A hydrodynamic thrust bearing comprising a rotating member having a plurality of spiral grooves on a convex surface, and a support member having a concave bearing surface that faces and cooperates with the convex surface of the rotating member, A slight difference is provided in the upper end position of the spiral groove on the convex surface of the rotating member, and the end position of some of the spiral grooves always has an optimal H dimension with respect to the upper plane of the support member. A dynamic pressure type thrust bearing characterized by holding.