JPH0725453Y2 - Spiral groove thrust bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an inward flow spiral groove thrust bearing.

[Prior Art] FIGS. 3 and 4 show a conventional spiral groove thrust bearing. The bearing 7 has a thick disk shape with a hole through which the rotary shaft 8 passes at the center, and the upper surface of the bearing 7 that supports the thrust collar 9 has a spiral groove 71 whose rotational direction is an inward direction. A land 72 is formed, and an inner peripheral land 73 is formed on the inner peripheral portion. With the rotation of the thrust collar 9, the lubricating fluid is guided to the inner diameter portion by the inward spiral groove 71, and the lubricity and the load capacity are enhanced.

[Problems to be Solved by the Invention] The conventional spiral groove thrust bearing is as described above, but since the lubricating fluid is pushed inward from the outer peripheral portion, the temperature rises significantly toward the inside and the thermal expansion As a result, there was a problem that the inner peripheral land 73 was raised and burned out.

The present invention has been made to solve such a problem, and an object thereof is to obtain a spiral groove thrust bearing capable of preventing the occurrence of burnout due to thermal expansion of the inner peripheral portion.

[Means for Solving the Problems] A spiral groove thrust bearing according to the present invention reduces axial wall thickness of a member in the vicinity of the inner peripheral portion of the bearing, and has a large number of slits radially from the inner peripheral portion in the portion. It has been cut down.

[Operation] The spiral groove thrust bearing in this invention is
Since the lubricating fluid is pushed inward from the outer peripheral part by the rotation of the thrust collar, the temperature near the inner peripheral part of the bearing rises and the inner peripheral land part tends to rise in the axial direction due to thermal expansion, but near the inner peripheral part. Since the wall thickness is thin and the slit is formed, the portion is elastically deformed and pushed down as a cantilever by the dynamic pressure of the lubricating fluid, and the swelling in the axial direction of the portion is offset. In addition, since the thermal expansion in the circumferential direction is allowed by the slit, the swelling in the axial direction is reduced. Further, since this portion has a small wall thickness, a large amount of heat is radiated and the temperature rise is moderated. Due to this, the occurrence of burnout is prevented.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
1 and 2 show a spiral groove thrust bearing according to the present invention, FIG. 1 is a plan view of a thrust receiving surface, and FIG. 2 is a longitudinal sectional view. In the drawing, reference numeral 7 is a thrust bearing, 71 is a spiral groove, 72 is a spiral land, 73 is an inner peripheral land, 74 is a slit, and 75 is a hollow portion.

In FIGS. 1 and 2, the spiral groove thrust bearing 7 has a donut disk shape so as to pass a rotation shaft (not shown) (see FIG. 4), and is attached to a housing not shown. Spiral-shaped shallow spiral grooves 71 and spiral lands 72 are formed on the upper surface of the bearing 7, which is the thrust receiving surface, in the rotational direction toward the center, and the inner peripheral land is formed on the inner peripheral portion.
73 is formed. The lower portion of the inner peripheral portion of the bearing 7 is removed as indicated by a thinned portion 75 to be thin in the axial direction. Further, the inner peripheral land 73 is provided with a number of slits 74 radially outward from the inner peripheral edge. Slit 74
For example, as shown in the drawing, the inner peripheral land 73 is cut so as to face the center of the inner end of each spiral land 72 or a position slightly offset in the rotational direction. It is desirable to form the gap of the slit 74 as narrow as possible.

Next, the operation will be described. A lubricating fluid such as gas or lubricating oil is supplied between the upper surface of the bearing 7 and the lower surface of the thrust collar (see FIG. 4).

The thrust collar rotates counterclockwise in FIG. Then, the lubricating fluid is dragged by the rotation of the thrust collar and flows inward from the outer side along the spiral groove 71, and is pushed into the spiral land 72 between the spiral grooves 71 and the inner peripheral land 73 of the inner peripheral portion. The dynamic pressure is generated and the thrust load of the rotating thrust collar is supported. The spiral groove thrust bearing is often applied to a high speed rotating shaft.

Especially when the lubricating fluid is oil, since the oil has a high viscosity, the temperature increases due to the lubricating action while the lubricating oil flows from the outer circumference to the inner circumference of the bearing 7, and the temperature in the inner circumference becomes extremely high. Become. Therefore, the inner peripheral portion of the bearing 7 thermally expands and the inner peripheral land 73 rises, and the gap between the inner peripheral land 73 and the thrust collar tends to become smaller. However, in this spiral groove thrust bearing 7, the thickness of the inner peripheral portion is reduced by removing the back side of the inner peripheral portion of the bearing 7. Further, a large number of slits 74 are formed in the radial direction. Therefore, when high dynamic pressure is applied to the upper surface of the inner peripheral land 73,
The pressure causes the thin portion of the inner peripheral land 73 to be elastically deformed and pushed down as a cantilever beam, offsetting the rise due to thermal expansion and reducing the reduction of the gap. Further, since thermal expansion in the circumferential direction of the inner peripheral portion is allowed by the gap of the slit 74, compared with the conventional one in which expansion and contraction in the circumferential direction is restricted,
The expansion and contraction in the circumferential direction reduces the expansion and contraction in the axial direction. That is, the thermal expansion reduces swelling. With the above-described action, the inner peripheral land 73 is prevented from rising and the gap between the inner peripheral land 73 and the thrust collar is prevented from becoming small, and the occurrence of burnout is prevented. Since the slit 74 is for permitting thermal expansion in the circumferential direction and elastic deformation in the axial direction, the gap may be narrow, and the amount of lubricating fluid leaking from the slit 74 is small. Can be one. In addition, since the thickness of the inner peripheral portion is thin, heat dissipation is improved, and the above-mentioned temperature rise is alleviated.

[Effects of the Invention] As described above, according to the present invention, the thickness of the inner peripheral portion is reduced and the slit is formed, so that when the inner peripheral portion receives a load, it elastically deforms as a cantilever beam. Then pushed down,
It is possible to offset the rise of the inner peripheral portion, alleviate the decrease in the gap in the inner peripheral portion of the thrust receiving surface, and prevent the occurrence of burnout or the like.
As a result, a spiral groove thrust bearing having a higher load capacity than before can be obtained.

[Brief description of drawings]

1 and 2 show a spiral groove thrust bearing according to an embodiment of the present invention, FIG. 1 is a plan view of a thrust receiving surface, and FIG. 2 is a longitudinal sectional view. FIG. 3 is a plan view of a conventional spiral groove thrust bearing, and FIG. 4 is a vertical sectional view thereof. In the figure, 7 is a thrust bearing, 71 is a spiral groove, 72
Is a spiral land, 73 is an inner land, 74 is a slit,
75 is a meat removing part.

Claims (1)

[Scope of utility model registration request] 1. An inward flow spiral groove thrust bearing in which a thrust receiving surface is formed with a spiral groove inward in the rotational direction, the axial wall thickness of a member in the vicinity of the inner peripheral portion of the bearing is reduced, and the portion is reduced. Spiral groove thrust bearing characterized in that a number of slits are radially formed from the inner circumference.