JP3099012B1 - Hydrostatic bearing unit - Google Patents

Abstract

An object of the present invention is to reduce the size of each component device by preventing a fluid such as oil, which has conventionally leaked to the outside from a fluid pressure pocket, from leaking as much as possible. Make it an issue. SOLUTION: An upper member, a lower member supporting the upper member, and a surface of the upper member and a surface of the lower member opposed to each other,
A fluid pressure supply device for supplying a fluid of a predetermined pressure, wherein the upper member and the lower member are supported on one surface of the upper member and the lower member in a static pressure bearing structure which is supported so as to be relatively movable via the fluid. Is provided with an annular sealing means that contacts the other surface, and fluid is supplied to a fluid pressure pocket formed inside the sealing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic bearing unit most suitable for performing a centering operation such as positioning and leveling of a heavy object (workpiece) to be cut by a machine tool.

[0002]

2. Description of the Related Art Conventionally, for example, when processing a workpiece as a workpiece with a machine tool,
Place the work. Then, in order to perform cutting (for example, milling) while moving the processing portion of the machine tool with respect to the workpiece, after the work is installed on the surface plate, fine adjustment (coordinate system of the machine tool and the coordinate system of the workpiece is made) Centering work). However, a work having a weight of more than ten tons is often processed, and once placed on a surface plate, it cannot be easily moved due to a large friction coefficient between the work and the surface plate.

Therefore, conventionally, a static pressure supporting device is known in which oil of a predetermined pressure is pumped between a lower surface on a work side and an upper surface of a surface plate to reduce a frictional force therebetween. In this means, as shown in FIG. 8A, a table 51 as an upper member is placed on the upper surface of the surface plate 50, and a heavy work 53 is placed on the table 51.

On the lower surface of the table 51, an annular groove 5 is provided.
5 and a pump 57 operated by a motor 56
Supplies pressure oil set at a predetermined pressure to the annular groove 55 of the table 51 via the pipe 58. A hydraulic pocket is formed by the annular groove 55, and a gap is formed between the lower surface 51 a of the table 51 and the upper surface 50 a of the table 50, for example, an oil film portion (for example, more than ten μ). Each upper surface is a smooth surface having a small coefficient of friction, and the heavy work 53 can be easily moved in the horizontal direction as shown in FIG.

[0005]

However, since the above-mentioned device has a structure for supplying high-pressure oil into the annular groove 55, the oil leaks from the space between the platen 50 and the table 51 to the outside. It will be. Therefore, it is necessary to supply a large amount of high-pressure oil to the hydraulic pocket to replenish the leaking oil, and the leaked oil is collected and used.

[0006] As a result, there is a drawback that a device such as a hydraulic pump or a motor is increased in size in order to pump and recover a large amount of high-pressure oil.

Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to prevent a fluid such as oil which has leaked outside from a fluid pressure pocket from leaking as much as possible. Accordingly, it is an object to reduce the size of each component device.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to the problems solved all rather, as an electrostatic圧支Seung unit,
The feature is that the upper member on which the supported body is placed
And a lower member movably supporting the material.
Between the upper member surface and the lower member surface.
The upper member and the lower member
In the static pressure bearing unit supported movably,
One surface of the upper member and the lower member contacts the other surface
An annular sealing means is provided, inside the sealing means.
Is provided with a fluid pressure pocket capable of supplying fluid,
Also, as the sealing means, one of the upper member and the lower member
Has an annular fluid pressure space formed therein, into which the fluid pressure space is formed.
At the time of supplying the pressurized fluid, one side contacts the other side.
Elastic deformation .

Further, when a fluid such as oil is supplied into the fluid pressure pocket, it is possible to prevent the fluid from leaking from the fluid pressure pocket inadvertently. Even if the motor, pump, fluid recovery device, and the like are small, fluid of a predetermined pressure can be supplied into the fluid pressure pocket.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. 1 to 4 show the one embodiment, 1 is, for example, in surface plate fixed to the side of the machine tool NC floor type horizontal milling boring machine or the like, over the constant-plate 1, the machine tool A supported body (work) 3 to be machined is supported. The work 3 has a weight of, for example, more than ten tons.

A plurality of centering hydrostatic bearing units 5 are interposed between the work 3 and the surface plate 1. In this embodiment, the support units 5 are provided at four positions on the surface plate 1. A table 6 is mounted on each bearing unit 5.

Each bearing unit 5 includes a supporting member 7 as a lower member fixed to the base 1 and a moving member 9 as an upper member fixed to the lower surface of the table 6. Further, between the two members 7 and 9, pressure oil of a predetermined pressure is fed from the hydraulic pressure supply device 10.

The upper surface (smooth surface) 7a of each support member 7 is a smooth surface as shown in FIG. 3, and an oil passage for supplying oil to the smooth surface 7a is provided at the center of each support member 7. 12
One or more are formed.

The smooth surface 9a of the moving member 9 is a smooth surface similar to the smooth surface of the support member 7, and has an annular groove 13 centered on the oil passage 12.
3 is fitted with an O-ring 15 as a sealing means. The sealing means 15 is not particularly limited. For example, the sealing means 15 may be of a hollow metal as shown in FIG. 5 (a), or may have a C-shaped cross section as shown in FIG. 5 (b). good.

The oil passage 12 of each support member 7 is connected to the hydraulic supply device 10 through a pipe 21 as shown in FIG. The hydraulic supply device 10 includes a hydraulic pump 20 driven by a motor 18, and oil is supplied from the hydraulic pump 20 to each bearing unit 5 through a pipe 21. Reference numeral 25 denotes a relief valve for supplying oil of a predetermined pressure to each bearing unit 5.

The apparatus according to the present embodiment has the above-described configuration. Next, an example of use of the apparatus will be described. First, each support unit 5 is set on the base 1, and the table 6 is mounted on the support unit 5, and then the work 3 suspended by, for example, a crane is mounted on the table.

When the motor 18 of the hydraulic pressure supply device 10 is operated, the oil pumped from the hydraulic pump 20 is supplied to each bearing unit 5 through each pipe 21. That is, the pressurized oil is applied to the smooth surface 7a of the support
And a fluid pressure pocket (hydraulic pocket) 29 formed between the sliding surface 9a and the inside of the sealing means 15.

At this time, although the work 3 has a considerable weight, the pressurized oil in the hydraulic pocket inside the sealing means 15 moves between the smooth surface 7a of the support member 7 and the smooth surface 9a of the moving member 9. Therefore, a minute gap of about several tens μ is formed between the smooth surface 7a of the support member 7 and the smooth surface 9a of the moving member 9 via the oil.

Therefore, this pressure oil functions as a lubricating oil,
The sliding coefficient of friction of the moving member 9 with respect to the support member 7 becomes very small, and the work 3 can be easily moved to a predetermined position together with the moving member 9 to perform centering.
Further, when oil is supplied to the bearing unit 5, some oil leaks from between the sealing means 15 and the smooth surface 7 a of the support member 7. Direction (direction of pressing against the smooth surface 7a of the support member)
The amount of oil leaking is very small, and even if it leaks, it has a function of lubricating the smooth surface 7a of the support member 7 and the smooth surface 9a of the moving member 9 outside the sealing means 15. Further, it contributes to reduction of both frictional forces.

[0020] Figure 6 shows an implementation of the embodiment of the present invention, the embodiment shown in the figure, instead of providing the seal member 15 of the separate as such the O-ring as a sealing means, the moving member 9 The lower part is bulged. That is, an annular continuous fluid pressure space (hydraulic space) 26 is formed below the moving member 9, and the thin portion 9b below the hydraulic space 26 is expanded by elastic deformation.

The hydraulic pump 20 has a first pipe 27 for supplying pressure oil to a hydraulic space 26 of the sealing means, and a second pipe 28 for supplying pressure oil to a hydraulic pocket 29. Numeral 28 is controlled to a predetermined pressure by pressure reducing valves 30 and 31, respectively.

That is, the first pipe 27 for pumping oil into the hydraulic space 26 is supplied with higher pressure oil than the second pipe 28 for pumping oil into the hydraulic pocket. Accordingly, the oil supplied from the hydraulic pump 20 is pumped into the hydraulic space 26 through the first pipe 27, and causes the thin portion 9b to bulge downward and annularly. Therefore, the bulged thin portion 9b functions as a sealing means, and can maintain the sealing property with the smooth surface 7a of the support member 7. Such a sealing means is advantageous in terms of abrasion resistance and the like against sliding as compared with the O-ring, and is strong.

On the other hand, since the oil that has passed through the second pipe 28 is supplied into the hydraulic pocket 29, it functions as a lubricating oil, and the moving member 9 is moved to easily center the work 3.

FIG. 7 shows still another embodiment in which cylinder chambers 31 and 32 having different diameters are formed in the moving member 9. Specifically, the diameter of one cylinder chamber 31 is set to be larger than the diameter of the other cylinder chamber 32. And each cylinder chamber 3
1, 32 have piston portions 33, each having a different diameter.
A moving body 35 having a slidably fitted inside.

The piping 2 connected to the hydraulic pump 20
1 is branched and supplied to one cylinder chamber 31 and a hydraulic pocket. The other cylinder chamber 32 communicates with the hydraulic space 26 of the moving member 9 shown in FIG.

Therefore, the pressure oil fed from the hydraulic pump 20 is controlled to a predetermined pressure by the pressure reducing valve 38 connected to the pipe 21, and is supplied to one cylinder chamber 31 and the inside of the hydraulic pocket. . The oil that has entered one cylinder chamber 31 pushes the large-diameter piston section 33 to move the moving body 35 to the other cylinder chamber 32 side. For this reason, the oil in the other cylinder chamber 32 has a higher pressure (higher than the pressure in the hydraulic pocket) and bulges the thin portion 9b of the moving member 9, so that the bulge functions as a sealing means.
In such a device, the number of pipes can be reduced because the number of pipe paths is single.

The present invention is not limited to the above embodiment, and the fluid may be a liquid or gas other than oil. In each of the above embodiments, the work 3
Although the table 6 is interposed between the support unit 5 and each of the support units 5, the table 6 is not always necessary, and the work 3 may be directly mounted on the support unit 5.

Further, a plurality of seal members can be provided instead of a single seal member. In such a case, a fluid is supplied to the inside of each seal member. In addition, the sealing means 15 is provided on the upper member side, but may be provided on the lower member side.

Further, the support unit 5 is constituted by the support member 7 and the moving member 9, but may be constituted only by the moving member 9. In such a case, the surface plate 1 constitutes a lower member. In addition, the table 6 or the work 3 can be provided as an upper member, and the sealing means 15 can be provided at a plurality of positions of the table 6 or the work 3.

Further, as shown by a virtual line in FIG. 4, one or more oil passages 12 are formed on the moving member 9 side, or the oil passages 12 are formed on both the support member 7 and the moving member 9. It is also possible.

[0031]

As described above, the present invention provides an upper member and a lower member.
An annular seal on one side of the member that contacts the other
Means are provided, and a fluid is supplied inside the sealing means.
Possible hydraulic pockets are provided and the seal
As a means, an annular fluid is provided on one of the upper member and the lower member.
When a pressure space is formed and a pressure fluid is supplied into the fluid pressure space
Then, one surface side is elastically deformed so as to contact the other surface.
Since it is shaped , when a fluid such as oil is supplied into the fluid pressure pocket, it is possible to prevent the fluid from leaking from the fluid pressure pocket carelessly. As a result, the amount of leakage is smaller than in the prior art, and the size of the motor, pump, fluid recovery device, and the like can be reduced.

The portion swelled by the elastic deformation is
Function as a tool for resistance to sliding compared to O-rings
It is advantageous in terms of abrasion and the like, and becomes strong.

[Brief description of the drawings]

FIG. 1 is an overall front view including a partial cross section showing an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement of the static pressure bearing unit.

FIG. 3 is a sectional view showing a main part of the hydrostatic bearing unit.

FIG. 4 is a perspective view showing a rear surface of the moving member.

FIGS. 5A and 5B are cross-sectional views respectively showing an embodiment of a sealing means.

FIG. 6 is a schematic view including a partial cross section showing another embodiment of the present invention.

FIG. 7 is a schematic view including a partial cross section showing another embodiment of the present invention.

FIG. 8 is a schematic view including a partial cross section showing a conventional example.

[Description of Signs] 3 ... Work (supported member), 7 ... Support member (lower member), 7
a: smooth surface (surface), 9: moving member (upper member), 9b: smooth surface (surface), 10: hydraulic supply device (fluid pressure supply device), 15
... O-ring (sealing means), 26 ... Hydraulic space (fluid pressure space), 29 ... Hydraulic pocket (fluid pressure pocket)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23Q 3/15 F16C 32/06

Claims (1)

(57) [Claims] An upper member on which a supported body is placed;
And a lower member that movably supports the member.
Between the surface of the upper member and the surface of the lower member.
By supplying, the upper member and the lower member mutually
In the static pressure bearing unit supported movably with respect to
One surface of the upper member and the lower member is in contact with the other surface.
Annular sealing means is provided, inside the sealing means.
Is provided with a fluid pressure pocket capable of supplying fluid,
Also, as the sealing means, one of the upper member and the lower member
Has an annular fluid pressure space formed therein, into which the fluid pressure space is formed.
At the time of supplying the pressurized fluid, one side contacts the other side.
Hydrostatic bearing unit characterized by elastic deformation
To