JPS6215541Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a sliding type hydrostatic bearing. Sliding hydrostatic bearings are used when precise linear movement is required, such as the Michelson interferometer in a spectrophotometer. Figure 1 is a vertical sectional view showing a conventional hydrostatic bearing used for sliding the movable mirror of a Michelson interferometer, and Figure 2 is a vertical cross-sectional view of the conventional hydrostatic bearing used for sliding the movable mirror of a Michelson interferometer.
FIG. In the figure, reference numeral 1 denotes a cylindrical bearing, which has a sliding hole 2 in the center. 3 is a hollow cylindrical sliding shaft provided to slide in this sliding hole 2, and has an air chamber 4 inside, and a peripheral portion from this air chamber 4 to a sliding gap 5. Two rows of air outlets 6 are provided to blow out air. 7 is an overhanging portion of the sliding shaft 3, 8 is an air supply connection pipe, and 9 is an air supply pipe.

In the hydrostatic bearing configured as above,
When air is supplied from the air supply pipe 9, the air flows into the air chamber 4.
The air is blown out from the air through the air outlet 6 into the sliding gap 5, where it flows in directions F ₁ and F ₂ respectively towards the shaft end, and the sliding shaft 3 is floated in the bearing 1 by this air flow. Since the blow-off ports 6 are arranged in two rows at intervals in the axial direction, the flow of the blown air is F ₁
and F The line flow is in _{the 2} direction, and flows uniformly through the sliding gap 5. In the Michelson interferometer, the sliding shaft 3 is connected to a movable mirror on the left side of the figure, and is slid in a floating state by a driving device such as a voice coil (none of which is shown) installed on the right side of the figure. Moving hole 2
Slide inside left and right.

The hydrostatic bearing with the above configuration is cylindrical, and the sliding center coincides with the part that requires precision (the movable mirror in the Michelson interferometer), so it is sensitive to temperature changes,
Disturbances such as vibrations have little effect on sliding accuracy.
Since the sliding accuracy is determined by the accuracy of the bearing 1 alone, it has the advantage that there is no need to improve the accuracy of many parts. It is necessary to provide a
Further, there were drawbacks such as the inability to perform multi-row blowing with three or more rows.

This idea is intended to improve the above-mentioned drawbacks of the conventional technology, and is designed to avoid the fluid outlet on the sliding surface of at least one of the bearing and the sliding shaft, and to direct the fluid outflow path in the axial direction of the bearing. By arranging them at symmetrical positions with respect to the axis, the air supply pipes can be installed on the side wall, which allows the overhanging part to be omitted and the device to be made more compact, as well as allowing for stable sliding. The purpose is to provide a hydrostatic bearing with high sliding accuracy.

This invention includes a bearing, a hollow cylindrical sliding shaft slidably provided in a sliding hole of the bearing, and a sliding surface of at least one of the bearing and the sliding shaft formed along the axial direction. , and fluid outflow passages formed at symmetrical positions with respect to the axis of the bearing,
A fluid outlet is provided on the outer periphery of the sliding shaft so as to avoid the fluid outflow path and jets pressurized fluid toward the sliding gap, and a fluid outlet is provided on the sliding shaft at a position corresponding to the fluid outflow path. This is a hydrostatic bearing characterized by comprising a fluid supply pipe connected to the sliding shaft and supplying pressurized fluid to the inside of the sliding shaft.

This invention will be explained below with reference to illustrated embodiments.
Fig. 3 is a horizontal sectional view showing a hydrostatic bearing according to an embodiment in which this invention is applied to the sliding of a moving mirror of a Michelson interferometer, Fig. 4 is a sectional view thereof, and Fig. 5 is a perspective view of the sliding shaft. 6 is a cross-sectional view thereof, FIG. 7 is a perspective view of the bearing, and FIG. 8 is a perspective view showing the assembled state. The same reference numerals as in FIGS. 1 and 2 indicate the same or equivalent parts. ing. Each figure is illustrated with different cut planes and orientations for ease of understanding.

In FIGS. 3 to 8, the bearing 1 and the sliding shaft 3 are constructed almost the same as those in FIGS. 1 and 2, but the air outlet 6 has a sliding The sliding shaft 3 is concentrated on the upper and lower sides of the Y direction of the shaft 3 and is provided at equal intervals in the radial direction, and the sliding portion of the sliding shaft 3 in the horizontal direction where no air outlet is provided, that is, in the direction perpendicular to the Y direction. On the outer periphery, groove-shaped air outflow passages 10 are provided in the axial direction symmetrically across the axis of the bearing 1 (and sliding shaft 3). An air supply connecting pipe 8 is connected to the center of one air outlet passage 10.
The air supply pipe 9 is connected through the air supply connecting pipe 8.
is slidably provided through an elongated hole 11 provided in the side wall of the bearing 1.

In the hydrostatic bearing configured as above,
When air is supplied from the air supply pipe 9, the air flows into the air chamber 4.
from the air outlet 6 to the sliding gap 5,
The air flows in the F ₁ and F ₂ directions, and the sliding shaft 3 floats in the bearing 1 due to this air flow. In this case, the air blown out from the outlet 6 near the air outflow path 10 flows in the direction of the air outflow path 10, as shown in FIG. 5, and is no longer a line flow. When the angle between the air outlet 6 and the Y axis is θ, the sliding shaft 3 generates a buoyant force of cos θ in the Y direction, and a buoyant force of sin θ in the X direction.

By arranging the air outlets 6 radially in the Y direction in this manner, buoyancy is also generated in the X direction. Even if the air outflow path 10 is processed, it will have little effect on the accuracy of the bearing 1, so the air supply pipe 9 can be connected to this part.
The overhanging portion 7 in FIGS. 1 and 2 can be omitted. Further, since the elongated hole 11 is provided in the air outlet path 10 of the bearing 1, various applications are possible.

Furthermore, since the air outflow passages 10 that are open to the atmosphere are formed at symmetrical positions with respect to the axis of the bearing 1 (and the sliding shaft 3), when the sliding shaft 3 moves, the sliding shaft can be moved in a stable state without being biased toward one side of the air outflow path 10. As a result, it is possible to make the sliding movement smooth and prevent a decrease in sliding accuracy.

FIG. 9 is a horizontal sectional view showing another embodiment,
In this embodiment, air supply pipes 9 are connected to air outlet passages 10 provided on both sides of the sliding shaft 3 via air supply connection pipes 8, and bearings 1
Elongated holes 11 are formed on both sides. This increases symmetry and improves balance.

FIG. 10 is a vertical cross-sectional view showing yet another embodiment, in which the air supply pipe 9 is connected to one air outlet path 10, but the elongated holes 11 are provided on both sides to increase the symmetry. This reduces distortion during processing. In this case, the output of the sliding shaft 3 can be extracted from the elongated hole 11 where the air supply pipe 9 is not provided.

FIG. 11 is a perspective view of a bearing showing another embodiment. In this embodiment, the air outflow passage 10 is formed in the shape of a groove in the sliding portion of the inner wall of the bearing 1, and the sliding shaft 3
Although not shown, it has a perfect cylindrical shape. The effect is similar to that described above.

FIG. 12 is an exploded perspective view showing yet another embodiment. In this example, air outflow passages 10 and elongated holes 11 are provided not only in the X direction but also above and below in the Y direction, and the same effect can be achieved. play.

Fig. 13 is an exploded perspective view showing yet another embodiment, which has three or more rows of air outlets 6 to increase the bearing rigidity. Conventional sliding bearings use line flow, and since there is no place for the air to escape, it is difficult to achieve multi-row air outlet, but by providing air outlet passages 10, it is possible to achieve multi-row air outlet similar to that of a rotary bearing. In this case, an auxiliary outlet passage may be provided perpendicular to the air outlet passage 10.

In addition, although the case where air was used as a fluid was shown in the said Example, gas or liquid other than air may be sufficient. Further, the fluid outflow path may be provided on either the bearing or the sliding shaft, and its structure is not limited to the groove shape, but may be chamfered or other structures. Further, the locations where the fluid outflow channels are provided are not limited to the X and Y directions, but may be provided in other directions, and the number thereof is not limited. Furthermore, the present invention is applicable not only to the movement of the movable mirror of a Michelson interferometer, but also to other devices that require linear motion.

As explained above, according to this idea,
The fluid outflow passages are formed on the sliding surface of at least one of the bearing and the sliding shaft so as to avoid the fluid outlet, and are arranged in the axial direction and at symmetrical positions with respect to the axis of the bearing. Therefore, there are no restrictions on line flow, thereby reducing restrictions on bearing design, and it is also possible to supply air from the side, and the axially extending portion can be omitted, making it possible to downsize the device. In addition, multi-row blowout is possible, which increases bearing rigidity, and allows the sliding shaft to slide in a stable state without being biased to one side of the air outlet path, resulting in smooth movement. Moreover, effects such as being able to prevent a decrease in sliding accuracy can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing a conventional hydrostatic bearing, Fig. 2 is a vertical sectional view thereof, Figs. 3 to 8 show an embodiment of this invention, and Fig. 3 is a horizontal sectional view of a conventional hydrostatic bearing. 4 is a cross-sectional view thereof, FIG. 5 is a perspective view of the sliding shaft, FIG. 6 is a cross-sectional view thereof, and FIG. 7 is a cross-sectional view thereof.
FIG. 8 is a perspective view of the bearing, FIG. 8 is a perspective view showing the assembled state, FIGS. 9 to 13 each show other embodiments, FIG. 9 is a horizontal sectional view of the hydrostatic bearing, and FIG.
The figure is a vertical sectional view of the hydrostatic bearing, FIG. 11 is a perspective view of the bearing, and FIGS. 12 and 13 are exploded perspective views of the bearing. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is a bearing, 3 is a sliding shaft, 4 is an air chamber, 6 is an air outlet, 9 is an air supply pipe, 10 is an air outlet path, and 11 is a long hole. be.

Claims (1)

[Claims for Utility Model Registration] (1) A bearing, a hollow cylindrical sliding shaft slidably provided in a sliding hole of the bearing, and a sliding surface of at least one of the bearing and the sliding shaft. fluid outflow passages formed along the axial direction and at symmetrical positions with respect to the axis of the bearing;
A fluid outlet is provided on the outer periphery of the sliding shaft so as to avoid the fluid outflow path and jets pressurized fluid toward the sliding gap, and a fluid outlet is provided on the sliding shaft at a position corresponding to the fluid outflow path. What is claimed is: 1. A hydrostatic bearing comprising a fluid supply pipe connected to the sliding shaft and supplying pressurized fluid to the inside of the sliding shaft. (2) The hydrostatic bearing according to claim 1, wherein two or more rows of fluid outlets are provided. (3) The hydrostatic bearing according to claim 1 or 2, wherein the pressurized fluid is air.