JP4166421B2 - Pneumatic floating support device - Google Patents

Description

[0001]
【Technical field】
The present invention relates to a pneumatic floating support device used in, for example, a vibration isolation device.
[0002]
[Prior art and its problems]
The vibration isolator is used as a device (base) on which a device that dislikes minute vibrations such as a stepper is placed. Conventionally, as a type of vibration isolator, a pressure air chamber is formed between a fixed base and a movable base via a flexible airtight member, and by controlling the intake and exhaust of pressurized air in the pressure air chamber, A pneumatic floating support device based on the principle of keeping the movable base in a floating state and preventing the propagation of vibration is known.
[0003]
In the conventional pneumatic floating support device, there is no means other than increasing the pressure of pressurized air or increasing the pressure receiving area of the movable base in order to increase the output (load holding capacity). However, the former must increase the pressure resistance, and the latter increases the planar size.
[0004]
OBJECT OF THE INVENTION
It is an object of the present invention to obtain a pneumatic floating support device capable of easily obtaining a required output (load holding capacity) without increasing the size in plan and increasing the pressurized air pressure. Objective.
[0005]
SUMMARY OF THE INVENTION
The pneumatic floating support device according to the present invention includes first and second pressure air chambers formed between a fixed base and a movable base, which do not have a mechanical contact portion, via flexible airtight members, respectively . One pressure air chamber is formed to move the movable base in a direction against gravity when pressurized air is supplied to the first pressure air chamber; Being configured to move the movable table in the direction of gravity when pressurized air is supplied to the second pressurized air chamber;
The pressure receiving area of the movable table by the first pressure air chamber is set to be wider than the pressure receiving area of the movable table by the second pressure air chamber; the first and second pressure air chambers are always applied with the same pressure. Communicating with each other so that pressurized air is supplied, and when the pressurized air is supplied, the movable table is given a force that rises relative to the fixed table due to the difference in pressure receiving area; And a supply means for supplying pressurized air to the second pressure air chamber .
[0006]
According to this pneumatic floating support device, the necessary output can be obtained without increasing the planar size by forming the required number of first and second pressure air chambers that are paired in the vertical direction. be able to.
[0007]
Independently pressurized air that moves the movable table in a direction against gravity through a flexible airtight member separately from the first and second pressure air chambers that form a pair between the fixed table and the movable table. It is preferable to form a chamber.
[0008]
The flexible hermetic member can be composed of an elastic member having various cross-sectional shapes. For example, the flexible hermetic member is composed of a bellows having a cylindrical shape as a whole and having at least one semicircular cross-sectional portion (waveform deforming portion). Can do.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment in principle of a pneumatic floating support device according to the present invention. The fixed base 20 fixed on the foundation 10 has a bottomed cylindrical shape having a bottom wall 21 and a cylindrical portion 22, and extends inward in the radial direction within the cylindrical portion 22 and is spaced apart in the vertical direction. The annular plates 23A and 23B (two in the illustrated example) are integrally provided. A through hole 24 exists in the center of the annular plates 23A and 23B.
[0010]
The movable base 30 includes a shaft portion 31 that is positioned in a non-contact manner in the through hole 24 of the fixed base 20, and three disks 32 </ b> A, 32 </ b> B, and 32 </ b> C provided integrally with the shaft portion 31 so as to be separated from each other in the axial direction. The three discs 32A, 32B, 32C are, in order from the bottom, between the bottom wall 21 and the annular plate 23A of the fixed base 20, between the annular plate 23A and the annular plate 23B, and the annular plate at the upper end. It is located above 23B. Although the fixed base 20 and the movable base 30 are illustrated as one member, they are actually divided into a plurality of members.
[0011]
An independent pressure air chamber 42 is formed between the bottom wall 21 of the fixed base 20 and the disc 32 </ b> A of the movable base 30 via a bellows 41. The independent pressure air chamber 42 is sequentially connected to the on-off valve 44, the regulator 45, and the pressurized air source 46 through the pipe line 43. When the pressurized air is supplied, the independent pressure air chamber 42 resists gravity. Move in the direction.
[0012]
The same configuration is provided between the annular plate 23A of the fixed base 20 and the disks 32A and 32B of the movable base 30, and between the annular plate 23B of the fixed base 20 and the disks 32B and 32C of the movable base 30. A first pressure air chamber 51 and a second pressure air chamber 52 are formed. That is, the first pressure air chamber 51 is formed by the large-diameter bellows 53 between the annular plate 23A and the disc 32B and between the annular plate 23B and the disc 32C. Are formed by the small-diameter bellows 54 between the annular plate 23A and the disc 32A, and between the annular plate 23B and the disc 32B. The first pressure air chamber 51 and the second pressure air chamber 52 are sequentially connected to the same on-off valve 44, regulator 45, and pressurized air source 46 as those for the independent pressure air chamber 42 through a pipeline 55, respectively. .
[0013]
According to the above configuration, if pressurized air is supplied to the first pressure air chamber 51, a force that moves in the direction against gravity acts on the movable table 30, and pressurized air is applied to the second pressure air chamber 52. When supplied, a force that moves in the direction of gravity acts on the movable table 30. However, the large diameter bellows 53 has a larger diameter than the small diameter bellows 54, and the pressure receiving area A of the movable table 30 by the first pressure air chamber 51 is larger than the pressure receiving area a of the movable table 30 by the second pressure air chamber 52. Now, if the pressurized air pressure supplied to the first pressure air chamber 51 and the second pressure air chamber 52 is P, the movable table 30 is lifted by the paired first pressure air chamber 51 and the second pressure air chamber 52. The direction force is
P × A−P × a = (A−a) × P
Given in.
[0014]
If the pressure receiving area of the movable table 30 by the independent pressure air chamber 42 (bellows 41) is the same A, in the illustrated embodiment, two pairs of the first pressure air chamber 51 and the second pressure air chamber 52 are provided. When all the air pressure chambers (independent air pressure chambers 42, first and second pressure air chambers 51, 52) are simultaneously supplied with compressed air having a pressure P via the compressed air source 46, The force X in the direction against the gravity received by the movable table 30 is
X = P × A + 2 (A−a) × P
= (3A-2a) x P
It becomes.
[0015]
Thus, according to the present embodiment, the first pressure that makes a pair as necessary without increasing the planar size of the fixed base 20 and the movable base 30 and without increasing the pressurized air pressure. By increasing the number of the air chambers 51 and the second pressure air chambers 52, the movable table 30 can be moved in a direction against gravity with a large force. In applications where it is desired to secure a space between the bottom wall 21 of the fixed base 20 and the disc 32A of the movable base 30, the independent pressure air chamber 42 (bellows 41) can be omitted. On the contrary, in the illustrated embodiment, only one pair of the first pressure air chamber 51 and the second pressure air chamber 52 may be provided.
[0016]
FIG. 2 is a more specific example of the shape of the vibration isolation device to which the pneumatic floating support device according to the present invention is applied. The shapes of the fixed base 20 and the movable base 30 are complicated depending on the actual apparatus configuration, but the first pressure air chamber 51 and the second pressure air chamber 52 are two pairs in FIG. Except for the fact that 2 is only a pair, the basic apparatus configuration is the same as in FIG. 1, and the components corresponding to the components in FIG. Moreover, although the fixed base 20 and the movable base 30 are illustrated as one member similarly to FIG. 1, it is actually divided into a plurality of members.
[0017]
In the embodiment of FIG. 2, in addition to the bellows 53 and 54 that form the first pressure air chamber 51 and the second pressure air chamber 52 (vertical direction) between the fixed base 20 and the movable base 30, the axis is A horizontal bellows 60 is provided in the horizontal direction, and by supplying pressurized air to the horizontal bellows 60, horizontal vibration isolation can be achieved.
[0018]
【The invention's effect】
As described above, according to the pneumatic floating support device of the present invention, the movable table can be supported in a floating state with a large output without increasing the planar size or increasing the supply air pressure. it can.
[Brief description of the drawings]
1 is a cross-sectional view showing a principle embodiment of a pneumatic floating support device according to the present invention;
FIG. 2 is a cross-sectional view showing a more specific embodiment of the pneumatic floating support device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Base 20 Fixed base 21 Bottom wall 22 Cylindrical part 23A 23B Annular plate 24 Through hole 30 Movable base 31 Axial part 32A 32B 32C Disc 41 Bellows 42 Independent pressure air chamber 43 55 Pipe 44 Open / close valve 45 Regulator 46 Pressurized air Source 51 First pressure air chamber 52 Second pressure air chamber 53 Large diameter bellows 54 Small diameter bellows

Claims (4)

First and second pressure air chambers formed between a fixed base and a movable base, which do not have a mechanical contact portion, via flexible airtight members, respectively;
The first pressure air chamber is formed to move the movable base in a direction against gravity when pressurized air is supplied to the first pressure air chamber;
The second pressure air chamber is formed to move the movable base in the direction of gravity when pressurized air is supplied to the second pressure air chamber;
The pressure receiving area of the movable table by the first pressure air chamber is set wider than the pressure receiving area of the movable table by the second pressure air chamber;
The first and second pressure air chambers communicate with each other so that pressurized air of the same pressure is always supplied. When the pressurized air is supplied, the first and second pressure air chambers move depending on the difference in the pressure receiving area. Providing the table with a force that rises relative to the fixed table; and supply means for supplying pressurized air to the first and second pressure air chambers;
A pneumatic floating support device comprising: 2. The pneumatic floating support device according to claim 1, wherein the first and second pressurized air chambers are formed by overlapping a plurality of pairs in the vertical direction. The pneumatic floating support device according to claim 1 or 2, wherein a flexible airtight member is interposed between the fixed base and the movable base separately from the paired first and second pressure air chambers. A pneumatic floating support device in which an independent pressure air chamber is formed to move the movable table in a direction against gravity. The pneumatic floating support device according to any one of claims 1 to 3, wherein the flexible airtight member comprises a bellows having a cylindrical shape as a whole and having at least one semicircular section. .

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