JPS6316608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydrodynamic bearing device.

Structure of a conventional example and its problems A conventional hydrodynamic bearing device (hereinafter simply referred to as a hydrodynamic bearing device) has a housing 1 having a bearing hole 1a with high precision as shown in Figs. A thrust bearing member 2 is attached to the lower part of the housing 1 at right angles to the hole, and a shaft 3 is rotatably provided in the hole 1a of the housing 1. A group 3d is formed on the shaft 3 by etching or the like, and a lubricating oil 4a such as oil or grease is applied. On the other hand, on the upper surface of the thrust bearing member 2, a group 2a having a shape as shown in FIG. A fluid bearing in the direction is configured. At this time, gas 5 such as air remains in the sealed bearing section. When either the shaft 3 or the housing 1 is rotated by a motor (not shown), pressure is generated by the pumping action of the groups 2a and 3d, and the rotation is performed without contact.

However, in the above configuration, when used in a low pressure state such as on a high mountain or outside the atmosphere, the gas 5 expands during depressurization and pushes the lubricating oil 4a in the radial groove 1a upward. If the conventional bearing device is used horizontally at this time, this lubricating oil 4a
This has the disadvantage that the lubricating oil leaks out of the bearing, causing the bearing to run out of lubricating oil and seize up. Similarly, when a conventional bearing device is used under high pressure, the gas 5 contracts during the pressure increase and the lubricating oil 4a of the radial bearing is forced downward, and the radial groove 3d is lubricated. This had the disadvantage of running out of oil and causing seizing. These phenomena under low pressure and high pressure are caused by the absence of gas 5,
Even if the sealed bearing is uniformly lubricated,
A similar phenomenon occurs when the lubricating oils 4a and 4b contain minute air bubbles; for example, the lubricating oil 4b
This has the disadvantage that the bubbles inside expand during depressurization and cause the lubricating oil 4a of the radial bearing to flow out.

OBJECTS OF THE INVENTION In view of the above drawbacks, the present invention provides a hydrodynamic bearing device that can be used both under high pressure and under low pressure.

Structure of the Invention The present invention has a housing having a bearing hole, a shaft rotatably provided in the bearing hole, a groove that generates a radial force in the shaft or the housing, and a groove at the end of the shaft. has a thrust bearing member having a groove that generates a force in the thrust direction, and has a thin plate with a cutout for the purpose of a groove-like ventilation groove between the housing and the thrust bearing member, and both groups It is lubricated with lubricating oil and has the feature that it can be used under both high and low pressure.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 to 6. In the figure, 11 is a housing, and this housing 11 has a hole 11a that serves as a bearing.
A groove 1 for a radial fluid bearing is provided therein, the lower end surface 13a of which is precisely finished to a flat surface, and a groove 1 for a radial fluid bearing.
A shaft 13 on which 3c and 13d are provided by etching or the like is rotatably provided. Further, a retaining ring 15 is provided below this shaft.
Further, a thrust bearing member 12 is fixed to the housing 11 so as to face the lower end surface of the shaft 13. Further, a thin plate 17 is sandwiched between the housing 11 and the thrust bearing member 12. Thrust bearing member 12
The upper surface of the upper surface is processed with high precision by polishing or the like, and a group 12a is formed in the center by etching or the like. In addition, lubricating oil 14 is applied to three grooves along with the radial groups 13c and 13d, and when either the shaft 13 or the housing 11 is rotated at a constant speed by a motor (not shown), the grooves 12a, 13
Pressure is generated by the pumping action of c and 13d, and rotation is performed without contact.

17e is a ventilation groove, for example approximately C shown in FIG.
It is provided on a letter-shaped thin plate 17. Ventilation groove 1
7e communicates the atmosphere with the gas 16a such as air trapped in the bearing chamber shown in FIG. 4 to eliminate the pressure difference, that is, the ventilation groove 17
By expelling the gas 16a to the outside through the air passage 17e and, conversely, sending air from the outside into the bearing chamber through the ventilation groove 17e during pressurization, the lubricating oil does not leak out even under high pressure or low pressure, and the groove portion 12
a, 13c, and 13d are held by the surface tension and viscosity of the lubricating oil itself, and the performance is completely unchanged from that under normal pressure.

Next, there is a case where the lubricating oil 14 itself contains small air bubbles. Generally speaking, in a hydrodynamic bearing, when the shaft 13 or the housing 11 starts rotating, the density increases due to the pumping action of the grooves 12a and 13b. Since the large lubricating oil 14 is forced toward the center of the groove much more strongly than the small-density air bubbles, the lubricating oil 14 is forced into the center as a result, and the air bubbles are expelled from the groove. The bubbles expelled from this group are carried outside through the ventilation groove 17e in the same manner as described above. In this way, the bearing can achieve stable rotation.

Further, by providing the thin plate 17 having the ventilation groove 17e between the housing 11 and the thrust bearing member 12 as in the present invention, for example, a drilled hole (not shown) having a diameter of about 1 mm is provided in the thrust bearing member 12 parallel to the shaft 13. Compared to the method of providing ventilation holes, this method has a dust-proofing effect in that far less dust enters from the outside.

Note that 11b shown in FIG. 3 is a ventilation hole for communicating gas such as air contained between the grooves 13c and 13d of the shaft 13 with the atmosphere to prevent the lubricating oil 14 from spilling, and to prevent dust from entering. In order to prevent this, the diameter of the thin plate is made extremely small, and the thin plate having the notch may not be C-shaped but may be square or any other shape as long as it has a notch that communicates the inside and outside of the bearing chamber.

Effects of the Invention As described above, the present invention provides a hydrodynamic bearing that can perform well under both high and low pressures by providing a thin plate with ventilation grooves between the housing and the thrust bearing member, and its effects are significant. It is what it is.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional hydrodynamic bearing device, FIG. 2 is an explanatory diagram of the groove shape of the thrust bearing, FIG. 3 is a sectional view of a hydrodynamic bearing device according to an embodiment of the present invention, and FIG. 4 is a sectional view of a conventional hydrodynamic bearing device. Enlarged sectional view of the main parts of the device, No. 5
This figure is a plan view of the same thrust bearing member, and FIG. 6 is a plan view of a thin plate in one embodiment of the present invention. 11...Housing, 12...Thrust bearing member, 13...Shaft, 14...Lubricating oil, 13c, 13
d, 12a...Groove, 17...Thin plate, 17e
...Vent groove.

Claims (1)

[Claims] 1. A housing having a bearing hole, a shaft rotatably provided in the bearing hole, a thrust bearing member attached to an end face of the housing, and a notch, with the notch and the parts other than the notch being A thin plate is provided between the housing and the bearing member, has a group on either the shaft or the bearing hole, and has a group on either the contact surface between the thrust bearing member and the shaft. established,
A hydrodynamic bearing device in which lubricating oil is arranged around the group.