JPH0321765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a hydrostatic bearing in which a bearing part floats above a guide surface of a guide part by the inflow pressure of compressed fluid.

(Prior Art) Generally, a hydrostatic bearing having a configuration shown in FIG. 4 is known. In FIG. 4, reference numeral 1 indicates a linear guide section having a rectangular cross-sectional shape, and reference numeral 2 indicates a bearing section (movement table) disposed opposite to this guide section 1. As shown in FIG. In this case, as shown in FIG. 5, compressed fluid outlet ports 3 are formed in the bearing portion 2 at portions facing the guide surfaces 1a of the guide portion 1. Then, compressed fluid supplied from an appropriate compressed fluid supply mechanism (not shown) is supplied to the guide section 1 and the bearing section 2 through these blow-off ports 3.
(for example, between several micrometers and several tens of micrometers), and the bearing section 2 is floated from each guide surface 1a of the guide section 1 by the inflow pressure of this compressed fluid. This allows the bearing section 2 to move smoothly along the guide section 1.

By the way, in this type of device, if the guide surfaces 1a of the guide section 1 and the opposing surfaces 2a of the bearing section 2 are not maintained in a parallel state, the air outlet 3 of the bearing section 2 The compressed fluid flowing into the space between the guide section 1 and the bearing section 2 via...
Since it is easy to escape in the direction where the gap is large, there is a risk that the desired performance (rigidity, flying height, etc.) may not be obtained. Therefore, in the case of the conventional structure, it is necessary to improve the accuracy of parts such as parallelism and perpendicularity of the guide part 1 and the bearing part 2 (for example, the guide part 1 and the bearing part 2
(within 10% of 〓), making it difficult to manufacture and raising costs.

(Problems to be Solved by the Invention) In the case of the conventional structure, when each guide surface 1a of the guide part 1 and each opposing surface 2a of the bearing part 2 are not maintained in a parallel state. Since there was a risk that the specified performance (rigidity, flying height, etc.) could not be obtained, it was necessary to improve the precision of parts such as parallelism and perpendicularity of the guide part 1 and bearing part 2, making it difficult to manufacture and increasing costs. I had a problem with getting high.

The present invention has been made in view of the above-mentioned problems, and provides a hydrostatic bearing that does not require particularly high component precision of the guide section and bearing section, and can be manufactured easily and at reduced cost. The purpose is to

[Structure of the Invention] (Means for Solving the Problems) The present invention includes a guide section having a guide surface, and a bearing section disposed opposite to the guide surface of the guide section,
In the axial pressure bearing, in which compressed fluid flows into a space between the guide part and the bearing part, and the bearing part floats from the guide surface of the guide part by the inflow pressure of the compressed fluid, the guide part A pad piece that is spaced apart from and faces a guide surface and has a blowout port for the compressed fluid formed therein, and a self-adjusting part that returns the pad piece facing the guide part to a state parallel to the guide surface of the guide part. The self-adjusting part includes a support shaft made of a flexible elastic material disposed between the pad piece and the bearing part, and a part of the support shaft having an outer diameter larger than that of the support shaft. It consists of a small diameter part that is formed thin and has a spring action corresponding to the swinging movement of the pad piece.

(Function) Compressed fluid flows from the outlet of the pad piece into the space between this pad piece and the guide part, and the inflow pressure of this compressed fluid causes the bearing part to float from the guide surface of the guide part, and the pad If the pad piece deviates from the parallel state with the guide surface of the guide part, the pad piece is oscillated using the small diameter part of the support shaft as a rocking fulcrum, and the pad piece facing the guide part is moved to the guide surface of the guide part. This is to restore the parallel state.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.
This will be explained with reference to the figures. FIG. 1 shows a schematic configuration of the main parts of the hydrostatic bearing shown in FIG. table). In this case, the bearing portion 12 is provided with a housing 14 formed by joining four flat housing components 13 into a rectangular shape, as shown in FIG.

Further, a pair of static pressure fluid pads 15 are provided on the inner surface of each housing component 13 of the housing 14, respectively. This static pressure fluid pad 15
As shown in FIG.
When the pad pieces 17 are spaced apart from each other and are formed with a blowout port 16 for compressed fluid such as air, and the pad pieces 17 are out of a parallel state with respect to the guide surface 11a of the guide part 11, the guide part 11 Self-adjusting section 18 that returns to the state parallel to the guide surface 11a
are provided for each. In this case, the self-adjusting part 18 includes a support shaft 19 made of a flexible elastic material disposed between the pad piece 17 and the housing 14 of the bearing part 12, and a part of this support shaft 19. 1
A small diameter portion 2 is formed with an outer diameter smaller than that of the pad piece 9 and has a spring action that corresponds to the swinging motion of the pad piece 17.
It is formed from 0. Further, as the material of the support shaft 19, for example, a metal material such as spring steel, a plastic material, or the like is used. Further, a mounting flange 21 is formed at the base end of the support shaft 19 of the hydrostatic fluid pad 15.
1, a hydrostatic fluid pad 15 is screwed to the housing 14 of the bearing part 12. Further, a fluid passage 22 is formed in the axial center of the hydrostatic fluid pad 15 and communicated with the outlet 16 of the pad piece 17. A self-throttled portion 23 is formed at the tip of the fluid passage 22. The self-throttled portion 23 has a smaller hole diameter than other portions. Here, the material of the support shaft 19 is, for example, spring steel, and when the outer diameter of the support shaft 19 is set to, for example, about 5 to 10 mm, the outer diameter of the small diameter portion 20 is about 2 to 3 mm, and the outer diameter of the small diameter portion 20 is about 2 to 3 mm. The inner diameter (diameter) of the fluid passage 22 at the axial center of the shaft 19 is set to about 0.1 to 0.5 mm. Note that the pad piece 17 of the hydrostatic fluid pad 15 does not necessarily have to be circular, and may have a line-symmetrical shape other than circular with respect to the axis.

Next, the operation of the above configuration will be explained. First, when a hydrostatic bearing is used, compressed fluid such as air is supplied from an appropriate compressed fluid supply mechanism (not shown) through the fluid passage 22 to the hydrostatic fluid pad 15 as shown by the arrow in FIG. From the outlet 16... to the guide section 11 and the pad piece 17 of the static pressure fluid pad 15
It flows into the space between. The inflow pressure of this compressed fluid causes each guide surface 11 of the guide section 11 to
The pad piece 17 of the static pressure fluid pad 15 is floated from a. In this state, the pad piece 17 is
When the guide surface 11a of the guide section 11 deviates from the parallel state, a pressure difference occurs in each part between the guide surface 11a of the guide section 11 and the pad piece 17 of the static pressure fluid pad 15, so that the static pressure Support shaft 19 of fluid pad 15
is the guide surface 11a of the guide portion 11 centered on the small diameter portion 20.
The pad piece 17 of the hydrostatic fluid pad 15 is elastically deformed in the direction of reducing the pressure difference at each part between the pad piece 17 of the hydrostatic fluid pad 15, and the pad piece 17 of the hydrostatic fluid pad 15 is moved parallel to the guide surface 11a of the guide part 11. restore the condition.
The material of the support shaft 19 of the hydrostatic fluid pad 15 is, for example, spring steel, and when the outer diameter of the support shaft 19 is set to, for example, about 5 to 10 mm, the outer diameter of the small diameter portion 20 is Approximately 2 to 3 mm, support shaft 19
The inner diameter (diameter) of the fluid passage 22 at the axial center of the
Each is set to approximately 0.5 mm, so it is designed to have sufficient rigidity to prevent buckling against forces in the axial direction.

Therefore, in the case of the above configuration, the guide portion 11
A pad piece 17 is arranged facing away from the guide surface 11a of the guide section 11 and has a compressed fluid outlet 16 formed therein. Self-adjusting section 18 that returns to the state parallel to the guide surface 11a
A static pressure fluid pad 15 is provided in the bearing part 12, and when the pad piece 17 of the bearing part 12 deviates from the parallel state to the guide surface 11a of the guide part 11, it is guided by the restoring force of the self-adjusting part 18. Since the part 11 is returned to a state parallel to the guide surface 11a, the accuracy of the parts such as the parallelism and perpendicularity of the guide part 11 and the bearing part 12 is
It can be set to about 80 to 90% of 〓 between 2 and 〓. Therefore, compared to the conventional case where the accuracy of parts such as parallelism and perpendicularity of the guide part 11 and the bearing part 12 is kept within 10% of the distance between the guide part 11 and the bearing part 12, it is easier to manufacture. Facilitation and cost reduction can be achieved.

Furthermore, the outer peripheral surface of the support shaft 19 is cut to form the small diameter portion 2.
Self-adjusting section 18 by a simple operation of forming 0
Therefore, when manufacturing the self-adjusting portion 18, the troublesome work of manufacturing a spherical contact surface etc. can be omitted, and the work can be simplified.

Note that this invention is not limited to the above embodiments. For example, as shown in FIG. 3, a bearing is provided with a guide portion 42 having a substantially inverted trapezoidal cross-sectional shape protruding above a flat reference surface 41 and a housing 43 having a shape corresponding to the shape of the guide portion 42. A housing 43 of the bearing portion 44 is provided.
A plurality of static pressure fluid pads 15 may be attached to the inner surface.

Furthermore, it goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] According to the present invention, a pad piece is arranged facing away from the guide surface of the guide part and has a compressed fluid outlet formed therein, and the pad piece facing the guide part is placed on the guide surface of the guide part. a self-adjusting part for returning to a parallel state, the self-adjusting part including a support shaft made of a flexible elastic material disposed between the pad piece and the bearing part;
Since a part of this support shaft is formed with a small diameter part that has an outer diameter smaller than that of this support shaft and has a spring action corresponding to the rocking motion of the pad piece, the guide part and the bearing part are There is no need to particularly increase the accuracy of the parts, and manufacturing can be facilitated and costs can be reduced.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, with Figure 1 being a vertical cross-sectional view of the main parts showing a hydrostatic fluid pad, and Figure 2 being a vertical cross-sectional view showing the general structure of the entire hydrostatic bearing. 3 is a vertical sectional view of the main part showing another embodiment, FIGS. 4 and 5 show a conventional example, and FIG. 4 is a perspective view showing the schematic structure of the entire hydrostatic bearing. , FIG. 5 is a longitudinal sectional view of the same. 11... Guide section, 11a... Guide surface, 12...
Bearing part, 15... Static pressure fluid pad, 16... Air outlet, 17... Pad piece, 18... Self-adjusting part, 1
9... Support shaft, 20... Small diameter part.

Claims (1)

[Claims] 1 Consisting of a guide part having a guide surface and a bearing part arranged opposite to the guide surface of this guide part, compressed fluid flows into the space between the guide part and the bearing part, and the inflow of this compressed fluid A static pressure bearing in which the bearing part floats from the guide surface of the guide part by pressure, the pad piece being disposed opposite to the guide face of the guide part and having an outlet for the compressed fluid formed therein; and a self-adjusting part that returns the face of the pad piece facing the guide part to a state parallel to the guide surface of the guide part, the self-adjusting part being disposed between the pad piece and the bearing part. A support shaft made of a flexible elastic material, and a small diameter portion formed on a part of the support shaft with an outer diameter smaller than that of the support shaft and provided with a spring action corresponding to the swinging motion of the pad piece. A hydrostatic bearing characterized by comprising: