JPH0219330B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a hydrodynamic gas bearing, and particularly to a small-sized hydrodynamic gas bearing.

[Background of the invention]

For example, as described in Japanese Unexamined Patent Publication No. 57-57918, in a bearing that supports a shaft with a plurality of bearing pads, a conventional device aligns at least one of these bearing pads with the axis of the shaft. The shaft is supported by a pivot shaft that is movable in the radial direction, and the pivot shaft is equipped with a stopper to ensure a constant clearance between the bearing pad and the shaft when the shaft is stationary, and a stopper that provides vibration stability when the shaft rotates at high speed. A coil spring is provided as a preloading means to ensure that the starting torque is reduced and startup is made easier. This also greatly reduces wear and damage on the bearing pad and shaft surfaces, and further increases the speed of high-speed rotation. This guarantees vibration stability over time.

However, when using such a conventional structure in a small-sized device such as a microturbine, the structure is complicated and there is a limit to the miniaturization of the bearing device itself, resulting in an increase in the overall size of the microturbine. It was hot.

[Purpose of the invention]

An object of the present invention is to provide a hydrodynamic gas bearing for use in a small-sized device such as a micro expansion turbine, which facilitates the starting of a rotating body and allows the overall size of the bearing to be reduced.

[Summary of the invention]

The present invention provides a hydrodynamic gas bearing in which a rotating shaft is supported by a bearing pad, in which a bearing housing is disposed outside the bearing pad, and a movable pivot that swingably supports the bearing pad is provided through the bearing housing. , install a leaf spring with one end in contact with the movable pivot on the opposite side of the bearing housing in the axial direction of the rotary shaft, and when the rotary shaft is stationary, the leaf spring can be seen between the movable pivot and the rotary shaft to prevent rotation of the rotary shaft. By making it possible to contact the movable pivot at the same time,
Even in a dynamic pressure gas bearing used in a small device such as a micro expansion turbine, the orbit of a rotating body is made easier and the overall size can be reduced.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A pad 2 is installed on the outer periphery of the rotating shaft 1, and the pad 2 has a movable pivot 3 that can freely move in the radial direction.
Supported by The movable pivot 3 is located within the bearing housing 4, and one end thereof is in contact with a leaf spring 5 fixed to the bearing housing 4 with a set screw 6. Note that the leaf spring 5 is attached to the bearing housing 4 so as to be arranged in the axial direction of the rotating shaft 1. Further, the bearing housing 4 is provided with a fixed seat 4a near the movable pivot 3 integrally with the bearing housing 4. The fixed seat 4a is made higher than the end surface of the movable pivot 3 by a value δ corresponding to the thickness of the gas film formed between the rotating shaft 1 and the pad 2 when the rotating shaft 1 rotates. .

Due to the above, when the rotating shaft 1 is stopped, the leaf spring 5 is in contact with the fixed seat 4a, and when the rotating shaft 1 starts to start, a gas film is formed between the rotating shaft 1 and the pad 2. Then, the movable pivot 3 moves outward in the radial direction of the rotating shaft 1 and comes into contact with the leaf spring 5, thereby applying a preload to the pad 2.

According to the first embodiment, when the rotary shaft 1 is stopped, no preload is applied to the pad 2, and the rotary shaft 1 can be easily started, and when the rotary shaft 1 is driven, a preload is applied to the pad 2. As a result, the high-speed stability of the rotating shaft 1 can be ensured, so it has the functions necessary for a hydrodynamic gas bearing. They are arranged in the axial direction of the shaft 1 to reduce the installation space, which has the effect that the bearing unit integrated with the bearing housing 4 can be made smaller.

In this embodiment, the fixed seat 4a is provided on the bearing housing 4, but it may be provided on the leaf spring 5.

Next, another embodiment of the present invention will be described with reference to FIG.

In the same figure, the same reference numerals as in the previous embodiment indicate the same members. This embodiment differs from the previous embodiment in that there is a gap between the movable pivot 3 and the leaf spring 5.
The plate spring 5 is used instead of the fixed seat 4a that provides the gap δ.
An adjustment screw 7 is provided at the top so that the distance δ can be set.

As described above, according to this other embodiment, the same effects as the one embodiment described above can be obtained. Further, there is an effect that the distance between the movable pivot 3 and the leaf spring 5 can be adjusted.

In addition, it is also possible to combine the above-mentioned embodiment and this other embodiment so that the stop position of the leaf spring 5 is determined by the fixed seat 4a, and fine adjustment is made by the adjustment screw 7. Alternatively, a wedge-shaped member may be interposed between the leaf spring 5 and the bearing housing 4 to adjust the distance.

Further, as shown in FIG. 1, the leaf spring 5 of these embodiments can be extended to the opposite side with the part fixed to the bearing housing 4 by the set screw 6 symmetrical, so that another movable pivot can be supported. .

〔Effect of the invention〕

According to the present invention, in a hydrodynamic gas bearing used in a small-sized device such as a micro-expansion turbine, the orbit of a rotating body can be made easier and the entire bearing can be made smaller.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a hydrodynamic gas bearing which is an embodiment of the present invention, Fig. 2 is a side sectional view of Fig. 1 viewed from A, and Fig. 3 is another embodiment of the invention. FIG. 3 is a sectional view showing a hydrodynamic gas bearing. 1... Rotating shaft, 2... Pad, 3... Movable pivot, 4... Bearing housing, 4a... Fixed seat,
5... Leaf spring, 7... Adjustment screw.

Claims (1)

[Claims] 1. In a hydrodynamic gas bearing in which a rotating shaft is supported by a bearing pad, a bearing housing is disposed outside the bearing pad, and a movable pivot that swingably supports the bearing pad is provided to penetrate the bearing housing. , a leaf spring having one end in contact with the movable pivot is arranged and attached to the opposite side of the bearing housing in the axial direction of the rotating shaft, and when the rotating shaft is stationary, the leaf spring is inserted between the leaf spring and the movable pivot. 1. A hydrodynamic gas bearing, characterized in that a skein is provided so as to be able to come into contact with the movable pivot when the rotating shaft rotates.