Vibration isolator with a vertically effective pneumatic spring

Abstract

A vibration isolator with a pneumatic spring that is effective only in vertical direction, the pneumatic spring including a working space in which a vertically effective actuator is disposed.

Claims

1. A vibration isolator comprising: a pneumatic spring that is effective only in a vertical direction, the pneumatic spring having a working space, wherein at least one actuator effective in the vertical direction is arranged in the working space, wherein the vibration isolator comprises a flexible rod or buckling pendulum for vibration isolation in a horizontal direction, wherein the flexible rod or the buckling pendulum is arranged in an inner housing of the vibration isolator, which projects into the working space of the pneumatic spring.

2. The vibration isolator as claimed in claim 1, wherein the actuator is implemented as a solenoid actuator.

3. The vibration isolator as claimed in claim 1, wherein the vibration isolator has an inner housing and an outer housing with the working space disposed therebetween.

4. The vibration isolator as claimed in claim 3, wherein at least one coil extends around the inner housing and at least one magnet extends along the outer housing.

5. The vibration isolator as claimed in claim 3, comprising a plurality of actuators that are superposed.

6. The vibration isolator as claimed in claim 1, wherein the actuator is implemented as a solenoid actuator and comprises a coil and a magnet, wherein a gap between the coil and the magnet has a width of less than 5 mm.

7. The vibration isolator as claimed in claim 1, comprising at least one leaf spring arranged in the working space of the pneumatic spring, which is connected in parallel to the pneumatic spring.

8. The vibration isolator as claimed in claim 7, wherein the leaf spring is part of a leaf spring assembly.

9. A vibration isolation system, comprising at least one vibration isolator as claimed in claim 1.

10. The vibration isolation system as claimed in claim 9, wherein the vibration isolation system comprises equipment for processing semiconductor devices.

11. The vibration isolation system as claimed in claim 9, wherein the vibration isolation system comprises at least one sensor for detecting vibrations of a load mounted for vibration isolation or of the ground on which the vibration isolation system is disposed, and a control device for actively controlling the pneumatic spring or the actuator on the basis of signals from the at least one sensor.

12. The vibration isolation system as claimed in claim 9, further comprising at least one further actuator which is arranged outside of an outer housing of the actuator and is effective in the horizontal direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The subject matter of the invention will now be described in more detail with reference to the drawings of FIGS. 1 to 4.

(2) FIG. 1 shows a schematic sectional view of a vibration isolator according to the invention.

(3) FIG. 2 shows a view of the inner housing.

(4) FIG. 3 shows a view of the outer housing.

(5) FIG. 4 is a schematic view of a vibration isolation system which is equipped with actuators according to the invention.

DETAILED DESCRIPTION

(6) FIG. 1 is a schematic sectional view illustrating a vibration isolator 1 according to the invention. Vibration isolator 1 is configured as a pneumatic spring having a working space 4 and comprising a base part 2 and a head part 3 which is in particular designed as a piston plate and is connected to the load to be isolated or is part of the load to be isolated.

(7) The pneumatic spring comprises an outer housing 8 mounted on the base part 2 and an inner housing 9. Outer housing 8 and inner housing 9 are closed by an elastic membrane 5. Membrane 5 is secured to the outer housing by means of clamping ring 6 and to the inner housing 9 by means of clamping ring 7.

(8) Due to the pressure prevailing in the working space 4, which can be controlled via a pneumatic control valve (not illustrated), the inner housing 9 is supported pneumatically relative to the outer housing 8 and is movable in the vertical direction due to the elasticity of the membrane 5.

(9) In order to couple the pneumatic spring to the base part 2 with rigidity in the horizontal direction, a leaf spring assembly 13 comprising a plurality of leaf springs 14 spaced apart in the vertical direction is provided between the inner housing 9 and the outer housing 8.

(10) In the present exemplary embodiment, the connection of inner housing 9 and outer housing 8 is accomplished by fastening of the leaf spring assembly 13 to the base part 2.

(11) For an isolation effect in the horizontal direction, a bending rod 12 is provided which is connected to the head part by screw 10 and to the inner housing 9 by screw 11.

(12) Inner housing 9 has a cup-like shape, at least in sections thereof, and extends from head part 3 into the working space 4 of the pneumatic spring. This provides for a compact design and at the same time the buckling point is shifted downwards whereby the system is stabilized.

(13) The outer surface of inner housing 9 has a circular cylindrical shape, at least in sections thereof, and has at least one coil 15 applied thereon. In the present exemplary embodiment a plurality of coils 15 are clamped to the inner housing 9 in superposed relationship.

(14) To form a solenoid actuator, annular magnets 16 are installed in the outer housing 8 opposed to coils 15. Respective opposing coils 15 and magnets 16 define a solenoid actuator.

(15) This allows for a simple implementation and optionally for retrofitting into a vibration isolator as well.

(16) Preferably, first coils 15 are mounted to the inner housing 9 and then magnets 16 are mounted to the outer housing 8, and then these two assemblies are combined.

(17) Since the pneumatic spring is effective only in vertical direction, the gap between coil 15 and magnet 16 is narrow, which permits to generate a large force in a compact space.

(18) FIG. 2 shows a schematic sectional view of the preassembled inner housing of the vibration isolator illustrated in FIG. 1.

(19) Coils 15 are clamped onto the inner housing 9.

(20) Inner housing 9 comprises a lower part 23 and an upper part 22 mounted thereon which may serve as an abutment for coils 15.

(21) The lower part 23 narrows in the region of leaf spring assembly 13.

(22) Otherwise inner housing 9 is cup-shaped, and flexible rod 12 is fixed to the bottom of inner housing 9.

(23) FIG. 3 shows a schematic sectional view of outer housing 8.

(24) It can be seen that annular magnets 16 are inserted into the outer housing 8 having a circular cylindrical shape. They may be secured thereto by an adhesive bond (not shown), for example.

(25) Furthermore, clamping ring 6 can be seen arranged on top, which serves to secure the membrane (5 in FIG. 1). It will be understood that this clamping ring 6 has to be removed for assembly.

(26) FIG. 4 shows a schematic view of a vibration isolation system 18 which comprises a table 20 mounted for vibration isolation, on which equipment for processing semiconductor devices 24 is arranged.

(27) On table 20, sensors 19 are arranged which detect vibrations of the load to be isolated and which may be implemented in the form of velocity, acceleration, or distance sensors.

(28) Sensors 19 are coupled to a control device 21 which drives the vibration isolators 1 on which the table 20 is supported.

(29) In the present exemplary embodiment, control device 21 controls both a pneumatic control valve for the pneumatic spring and the solenoid actuator provided within the vibration isolator 1.

(30) Outside of the housing of vibration isolator 1, actuators 25 are arranged which enable active control in horizontal direction. These actuators are also actively controlled on the basis of sensors. The corresponding control loop is not illustrated here.

(31) The invention permits to provide, within a compact space, a vibration isolator operating on the pneumatic principle and enabling active control with large control forces.

LIST OF REFERENCE NUMERALS

(32) 1 Vibration isolator 2 Base part 3 Head part 4 Working space 5 Membrane 6 Clamping ring 7 Clamping ring 8 Outer housing 9 Inner housing 10 Screw 11 Screw 12 Flexible rod 13 Leaf spring assembly 14 Leaf spring 15 Coil 16 Magnet 17 Gap 18 Vibration isolation system 19 Sensor 20 Table 21 Control device 22 Upper part 23 Lower part 24 Apparatus for processing semiconductor devices 25 Actuator