Vibration isolator with pneumatic spring

Abstract

The invention relates to a vibration isolator with a pneumatic spring. The vibration isolator comprises a leaf spring assembly for vertical isolation and a flexible rod or a buckling pendulum for horizontal isolation.

Claims

1. A vibration isolation system comprising: a plurality of vibration isolators arranged in the vibration isolation system to vibration isolate a load, wherein the vibration isolators comprise: a pneumatic spring, wherein the pneumatic spring is connected with a head part via a flexible rod or a buckling pendulum, wherein the flexible rod or the buckling pendulum is coupled with a base part via at least one leaf spring effective only in a vertical direction, and wherein the at least one leaf spring comprises a plurality of spring segments connected in parallel, and wherein the at least one leaf spring comprises an inner ring connected to a piston and an outer ring connected to the base part.

2. The vibration isolation system as claimed in claim 1, wherein the pneumatic spring comprises the piston having an extension, wherein the flexible rod or the buckling pendulum is arranged in the extension, at least sections thereof.

3. The vibration isolation system as claimed in claim 2, wherein the extension protrudes into a working space of the piston.

4. The vibration isolation system as claimed in claim 3, wherein the flexible rod or the buckling pendulum protrudes into the working space over at least half the height of the working space.

5. The vibration isolation system as claimed in claim 1, wherein the at least one leaf spring is part of a leaf spring assembly.

6. The vibration isolation system as claimed in claim 5, wherein a plurality of leaf springs of the leaf spring assembly are spaced apart by spacer rings, wherein the plurality of leaf springs includes the at least one leaf spring.

7. The vibration isolation system as claimed in claim 1, wherein the vibration isolators have a natural frequency of more than 5 Hz in vertical or horizontal direction.

8. The vibration isolation system as claimed in claim 1, wherein the flexible rod or the buckling pendulum or the at least one leaf spring is exchangeable to adjust rigidity.

9. The vibration isolation system as claimed in claim 1, wherein the vibration isolation system has at least one sensor for detecting vibrations or a position of the load to be isolated or of a floor on which the vibration isolation system is arranged, and a control device for a fluid supply of the pneumatic spring, which is connected to the sensor.

10. The vibration isolation system as claimed in claim 9, wherein the level of the load to be isolated is adjustable via the pneumatic spring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The subject matter of the invention will now be described in more detail with reference to FIGS. 1 to 6.

(2) FIG. 1 shows a schematic principle diagram of a vibration isolator.

(3) FIG. 2 shows a sectional view of an exemplary embodiment of a vibration isolator.

(4) FIG. 3 shows another sectional view of a portion of a vibration isolator.

(5) FIG. 4 shows a partially broken away perspective view of an assembly comprising a vibration isolator.

(6) FIG. 5 shows a plan view of a leaf spring that can be used for a vibration isolator according to the invention.

(7) FIG. 6 is a schematic diagram of a vibration isolation system.

DETAILED DESCRIPTION

(8) The basic principle of the invention will now be explained with reference to the schematic view of FIG. 1.

(9) FIG. 1 shows a sectional view of a vibration isolator 1.

(10) The vibration isolator comprises a base part 2 and a head part 3 which is mounted with vibration isolation relative to base part 2.

(11) Head part 3 may be part of an assembly that forms the vibration isolator 1 which is then incorporated in a vibration isolation system. In this case, head part 3 may for example be secured to a table that is used for anti-vibration mounting of a lithography device.

(12) It is also conceivable that head part 3 is an integral part of the table.

(13) Vibration isolator 1 further comprises a working space 4 in which a fluid pressure exists and which supports a piston 5. Working space 4 is closed by a membrane (not shown) which makes the piston 5 movable relative to the remaining housing of the vibration isolator.

(14) Piston 5 comprises an extension 6 extending in vertical direction. In this exemplary embodiment, extension 6 is screw-connected to the remaining piston. However, a one-piece embodiment is also conceivable.

(15) A flexible rod 7 is attached to the bottom of this extension and is connected to the head part 3.

(16) In this manner, horizontal resilience is provided as the flexible rod 7 bends.

(17) Piston 5, in this exemplary embodiment extension 6 of piston 5, is connected to base part 2 via a leaf spring assembly 9.

(18) Leaf spring assembly 9 provides vibration isolation in vertical direction.

(19) Leaf spring assembly 9 primarily determines the rigidity of the isolator, while the pneumatic spring which is formed by working space 4 and piston 5 primarily serves for level adjustment.

(20) FIG. 2 shows a sectional view of an exemplary embodiment of a vibration isolator.

(21) The vibration isolator comprises base part 2 and head part 3 coupled thereto with vibration isolation.

(22) It can also be seen here that working space 4 is closed by a membrane 8 arranged below head part 3.

(23) Membrane 8 is connected to the housing 14 of working space 4 by means of a clamping ring 13.

(24) Furthermore, flexible rod 7 can be seen which is connected to head part 3 by screw 12.

(25) Flexible rod 7 is connected to extension 6 at the bottom thereof by means of screw 15. For this purpose, extension 6 includes a bottom part 20.

(26) By loosening the easily accessible screws 12 and 15, the flexible rod may be removed and replaced for adjusting the isolator. Screw 15 is accessible after screw 17 has been removed, which closes working space 4.

(27) Housing 14 of working space 4 is connected to base part 2 by screws 16.

(28) Furthermore, individual springs 10 and spacer rings 11 of the leaf spring assembly can be seen.

(29) The at least one fluid line which supplies working space 4 with fluid is not shown in this view.

(30) FIG. 3 shows a detailed view of a portion of a vibration isolator according to the invention, namely extension 6 connected to leaf spring assembly 9.

(31) It can be seen that at least a part of leaf spring assembly 9 is connected to base part 2 by screws 18 and to extension 6 by screws 19.

(32) After loosening the screws, leaf spring assembly 9 consisting of leaf springs and spacers can be removed.

(33) Spaced apart from leaf spring assembly 9, a lower leaf spring assembly 21 is arranged. Lower leaf spring assembly 21 and the bottom part are held by screws which cannot be seen in this sectional view.

(34) FIG. 4 shows a perspective view partially broken away of an assembly including a vibration isolator according to the invention.

(35) Base part 2 and head part 3 of the vibration isolator can be seen, as well as working space 4 therebetween through which flexible rod 7 extends which is arranged in an extension of the piston. Furthermore, spring assembly 9 can be seen which is effective in vertical direction, whereas flexible rod 7 is effective in horizontal direction.

(36) FIG. 5 shows a view of an exemplary leaf spring 10. The leaf spring shown in this exemplary embodiment comprises an inner ring 26 which has holes 27 in order to be fixed to the extension (6 in FIG. 3) of the piston.

(37) An outer ring 23 includes holes 24 in order to be fixed to the base part.

(38) In this embodiment, resiliency in vertical direction is ensured by three spring segments 25 connecting outer ring 23 and inner ring 26 and being connected in parallel.

(39) By exchanging or omitting suchlike leaf springs 10 in the spring assembly, the characteristics of the vibration isolator can be easily adjusted.

(40) FIG. 6 shows a schematic view of a vibration isolation system 30.

(41) This vibration isolation system comprises a table 31 which is supported on at least three vibration isolators 1.

(42) Sensors 29 are used to detect the level of the table at the position of each respective vibration isolator 1.

(43) Based on the signal of sensors 29, control device 28 controls the pressure in vibration isolators 1 and thus provides level compensation.

(44) It will be understood that the vibration isolation system may include additional sensors and/or actuators, in particular non-contact force actuators.

(45) By exchanging leaf springs in the spring assembly and/or the flexible rod, the vibration isolators 1 at the respective position may be adjusted to a same natural frequency in a very simple manner.

(46) TABLE-US-00001 List of Reference Numerals: 1 Vibration isolator 2 Base part 3 Head part 4 Working space 5 Piston 6 Extension 7 Flexible rod 8 Membrane 9 Leaf spring assembly 10 Leaf spring 11 Spacer ring 12 Screw 13 Clamping ring 14 Housing 15 Screw 16 Screw 17 Screw 18 Screw 19 Screw 20 Bottom part 21 Leaf spring assembly 22 Spacer ring 23 Outer ring 24 Hole 25 Spring segment 26 Inner ring 27 Hole 28 Control device 29 Sensor 30 Vibration isolation system 31 Table