JP2936238B2 - Air isolation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001] The present invention relates to the isolation of loads and other objects and to an air isolation device.

2. Information Disclosure Declaration A modern air isolator is a newport catalog (Newport, Corporation, 1989) A-2 to A-.
It is described on page 33. Such a state of the art air isolator, as seen, for example, on pages A-4 and A-22 of the Newport catalog, comprises a spring tank in which a oscillating piston displaces, and It has an external damping tank.

[0003] This spring tank, also known as a compliance chamber, provides a compression of a predetermined volume by a specific vibration isolation frequency, as can be seen, for example, from the equation on page A-4 and the description of the spring tank on page A-22. It contains gas, typically air.
The above comments also point out the importance of a damping tank, such as "a second chamber connected to a spring chamber by an orifice or other device that provides the necessary damping to limit flow and reduce amplitude at resonance". Emphasizes gender.

The best equipment for such purposes is Da
The 34th CIRP General Assembly 19 by Prof. niel B. DeBra
The design of a laminar flow restrictor for a damping air damper, filed in August 1984, can be seen from the report in FIG. 5 which shows a damping chamber in addition to the compliance chamber. Thus, a laminar flow restrictor.

Such damping chambers or tanks occupy considerable space, are shown larger than the compliance chambers in FIG. 5 of the CIRP bulletin, and include a spring tank in the Newport catalog on pages A-4 and A-22. It is shown as large as. This not only adds bulk to the device, but also imposes other limitations. When looking at the prior art drawings described so far, the pressure fluctuations imposed by the oscillating piston in a spring tank or compliance chamber may have given the tank or chamber a large volume with respect to the cross-sectional area of the oscillating piston. Nevertheless, it should be recognized that it is very small. The resulting pressure difference between the compliance chamber and the damping chamber results in minimal gas flow through laminar or other flow restrictors, and inefficient damping. This gives the designer little room to devise laminar or other flow restrictors and damping tanks or chambers.

In this regard, reference is made to US Pat. No. 3,784,146 by Dr. John W. Matthews, issued Jan. 8, 1947, entitled "Horizontal Isolation System". This patent discloses a horizontal vibration isolator and provides a large air housing in which a piston assembly operating for each air vibration isolator is relatively displaced by vibration.

[0007] General Overview The purpose of the present invention of the present invention is to overcome the drawbacks that are expressed or implied to another portion of the "Disclosure Declaration" or the specification is to satisfy the request.

It is a related object of the present invention to provide an improved isolation of a load or other object.

It is a related object of the present invention to provide an improved air isolation device.

It is an object of the present invention to provide an improved air isolation method and apparatus. Other objects of the present invention will become clear later in the present disclosure.

The present invention resides in a method and apparatus for air vibration isolation wherein a working piston is displaced by vibration with respect to a compliance chamber containing a volume of compressed gas predetermined by a natural vibration isolation frequency. In one aspect, the present invention performs damping by mounting a working piston proximate a permeable pressure barrier in a compliance chamber and moving gas through the pressure barrier in the compliance chamber by the working piston. Thus, there is an improvement that eliminates the need for an external damping chamber.

In its related aspects, the present invention is directed to an external device comprising a pressure barrier in a compliance chamber permeable to gas moved by a working piston, and a coupling of mounting the working piston in close proximity. An improvement resides in eliminating the need for a damping chamber. Preferably, such a pressure barrier is as close to the working piston as allowed by the working piston travel.

[0013] The efficiency and effectiveness of the vibration isolator is further improved by providing laminar flow to the gas, which is preferably moved by the working piston through the pressure barrier in the compliance chamber.

[0014] Other objects of the present invention will become apparent during the course of this disclosure, but are not intended to be limited by this Summary of the Invention.

[0015] BRIEF DESCRIPTION invention and various aspects and objects thereof drawings, will become more apparent from the following detailed description of preferred embodiments thereof illustrated in the accompanying drawings for purposes of illustration. In the drawings, like reference numbers designate similar or equivalent parts.

FIG. 1 is a vertical sectional view of an air vibration isolator according to a preferred embodiment of the present invention.

FIG. 2 is a view similar to FIG. 1 illustrating two additional features, according to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings illustrate air that can be used, for example, to isolate a load, mass, machine or table 12 from vibrations of a floor 13 or to isolate a floor from vibrations of a machine. The anti-vibration devices 10 and 100 are illustrated. The table will typically have three or more such anti-vibration devices as legs for this purpose.

The anti-vibration devices 10 and 100 are of the type in which the working piston 15 is displaced by vibration with respect to a compliance chamber 16 containing a volume of compressed gas 17 which is predetermined by a specific anti-vibration frequency. For the determination of the appropriate gas volume, reference can be made to Equation (1) on page 2 of the CIRP bulletin and its description, and the guidance on page A-4 of the Newport Catalog.

However, unlike those prior art, the present invention mounts the working piston 15 in close proximity to a permeable pressure barrier 18 in a compliance chamber 16,
Actuating piston 15 then moves gas 20 through the pressure barrier in the compliance chamber, providing integrated damping control, thereby eliminating the need for an external damping chamber or volume.

According to a preferred embodiment of the invention, a laminar flow 19 is provided for the gas 20 moved by the working piston 15. A laminar damping orifice or restrictor 21 can be used for this purpose, and is disclosed in the aforementioned CIRP bulletin on vibration-induced airflow to the damping chamber, and is preferably sintered, for example, secured by a sealing grommet. A metal type may be used. However, contrary to the CIRP statement and other prior art, the present invention eliminates such a damping chamber or tank. Rather, the volume of all gases 17 in the compliance chamber 16
Are prevented from leaving the compliance chamber 16 by movement by the working piston 15. In other words, the compliance chamber 16 has a gas 17 leaving the compliance chamber 16 due to the movement of such gas by the working piston 15, as also indicated at 29.
Sealed against.

As shown at 23, gas may enter the compliance chamber through port 24 and may be removed from such chamber for leveling purposes, as indicated by the dashed arrow 25. . A muffler (not shown) may be attached to the port 24.

Acoustic damping can be achieved inside the compliance chamber 16. In this manner, the isolation of the mass 12 from the propagation of low-level sound waves can be achieved. The compliance chamber can be lined with acoustic damping material 26. Acoustic damping can be realized inside the pressure barrier 18 which can be lined with an acoustic damping material 28 for that purpose.

By mounting the pressure barrier 18 virtually as close as possible to the piston 15, the present invention allows the maximum amount of gas 20 to pass through the orifice 21 for each piston movement for maximum efficiency and effectiveness of the vibration isolator. Make sure that. The pressure barrier 18 is mounted as close to the piston 15 as permitted by the travel of the working piston.

As in the state-of-the-art equipment, the piston 15 can be sealed to the compliance chamber 16 by a diaphragm seal 31. In the present invention, the pressure barrier 18 is mounted as close to the piston as is permitted by the operation of the diaphragm seal and the travel of the operating piston.

To limit the vertical movement of the piston, one or more cushioned mechanical stops 32 can be located between the load support plate 35 and the top of the piston. According to the illustrated preferred embodiment, the stop is
It is in the form of a mechanical stop ring 32 extending around the inner edge of the stop plate 33 between the conical centering guide 46 for limiting the vertical and horizontal movement of the working piston 15 and the top of the piston 15.

The piston 15 is preferably mounted on a pendulum isolation system for isolating the horizontal component of the oscillation. Such a pendulum isolation system 36 is disclosed in the aforementioned U.S. Pat. No. 3,784,146 and Newport Catalog A-.
5 and A-22, and shows the top piston plate 44, the inner plate 62 with rods 74, and the suspension cable 84. The piston 15 can be provided with damping oil 37 at least around the plate 62.

If a horizontal vibration isolation system such as 36 is used, the pressure barrier is mounted as close to the piston 15 as permitted by such horizontal vibration isolation and the required working piston travel.

In the preferred embodiment shown, the piston has a pendulum isolation system 3 for isolating the horizontal component of the oscillation.
6 and said piston 15 is sealed against the compliance chamber 16 by a rolling diaphragm seal 31. The pressure barrier 18 is mounted as close to the piston 15 as permitted by the actuation of the rolling diaphragm seal, horizontal vibration isolation, and other necessary operating piston travel.

As shown at the top of FIGS. 1 and 2, the present invention provides for the actuation piston to operate prior to expansion of the compliance chamber by compressed gas 17 or during deflation, such as through port 24 of the compliance chamber. Is automatically centered. Means for such self-centering may include the illustrated contoured centering guide 46 on the working piston 15 or on its top plate 44. The contoured centering guide provides the compressed gas 17 at port 2 as indicated, for example, by the dotted arrow 25.
It has an inclined conical section 48 that contacts the stop 32 when the piston 15 descends as the isolator 10 or 100 is contracted or depressurized by draining from the compliance chamber through 4. This portion of the ramp section 48 is stopped 32 until the descending piston 15 is centered within the lateral contour of the pressure barrier 18 and the rolling diaphragm 31 or other seal.
Slide along the upper corner of the.

Therefore, if the vibration isolator 10 or 100
Or, if the compliance chamber is re-expanded by the compressed gas 17 through the port 24, as indicated, for example, by an arrow 23, the piston 15 is already in a centered state, which may result in a malfunction, in particular a table or other mass 12 Three or more anti-vibration devices 10 or 100
To prevent it when included.

A contoured centering guide 46 according to the present invention.
Or for other self-centering, the pressure barrier 18 prevents the piston 15 from tilting or otherwise contacting the side wall of the pressure barrier when the compliance chamber is re-inflated or re-pressurized. Therefore, it can be installed closer to the piston 15 and the seal 31.

The contoured centering guide 46 or other automatic centering of the present invention is performed by the horizontal vibration isolation suspension 36.
Enhance the usefulness of the. This is because such a suspension always starts from a centered state when its compliance chamber 16 is re-inflated or re-pressurized.

In the presently discussed aspect of the present invention, the piston 15 can be centered by mounting it in a tapered stop in a design that is the opposite of the design shown at 32 and 48. A centering guide within this range can be fixed to the vibration isolator body, at which time the lowered position centers itself on the fixed centering guide.

A contoured centering guide or other automatic centering system has utility even away from the pressure barrier 18. In fact, such centering itself has utility beyond the horizontal isolation suspension 36. This is because such automatic centering is such that the external damping chamber is connected to a spring or compliance chamber through an orifice, for example, as indicated in the Newport catalog and CIRP bulletin described above. This is also advantageous for the operation of the prior art air isolation system.

Although the same is shown in the environment of both the pressure barrier 18 and the horizontal isolation suspension 36, the same is true for the additional features shown in FIG.

In particular, an additional feature, shown as 51 in FIG. 2, senses the distance of piston 15 to pressure barrier 18 and adjusts such distance by adjusting the pressure of compressed gas 17. .

FIG. 2 in particular illustrates a valve 52 connected to a compliance chamber by a compressed gas line 53 through a port 24 for regulating the pressure of the compressed gas 17. FIG. 2 also shows a valve 5 which includes a link 55 extending in the travel direction of the working piston from the piston 15 to the valve 52.
2 illustrates an actuator 54 for the second. In FIG. 2, such a piston travel direction is vertical as shown. However, other arrangements are within the scope of the invention.

According to the embodiment shown in FIG. 2, the rod or link 55 is connected to the bottom of the piston 15 by a ball joint or swivel connection 56. The lower end of this rod is sealed by a diaphragm seal 58 which also wraps around the compliance chamber 16, but is much smaller in cross-section and otherwise than the first or primary piston 15
Connected to The link also includes a second ball joint or swivel connection 59 associated with a secondary piston 57.

A barrier tube 61 surrounds the connecting rod 55 between the pressure barrier 18 and the secondary piston 57 and seals the compliance chamber space 17 between the top and bottom of the compliance chamber 16.

For this reason, the link 55 or the secondary piston 5
7 to the valve actuator 54 and thereby the valve 5
Acts on 2. By way of example, a valve 52 is a spool type that alternately connects the compliance chamber port 24 to a gas exhaust line 63, as shown by a symbolic solid line 64, and to a gas supply line 65, as shown by a symbolic dotted line 66. The valve is good. Spool type valves and their construction are well known per se. If link 55
If the secondary piston 57 indicates that the piston 15 is too high for a given application, the valve 52
7 is released from the compliance chamber 16 as indicated by the arrow 67 in FIG.

Conversely, if such a link and the secondary piston indicate that the primary piston 15 is too low or too close to the pressure barrier 18, the valve 52 will have an arrow 68.
2, the compressed gas is received into the compliance chamber 16 through the port 24, whereby the working piston 15 is adjusted upward as shown in FIG. Adjustment of the height of the primary piston 15 or the vibration isolation system 100 can be performed by adjusting the valve 52 as shown by the double arrow 69 in FIG.
This is achieved by adjusting the position of the spool relative to the middle valve port. The housing of valve 52 may be vertically adjustable for that purpose.

Valve 52 in line with movement of piston 15
Position ensures minimal crosstalk in the leveling control feedback added by valve 52 and its adjustment 69.

This broad disclosure will make apparent to or suggest to those skilled in the art various modifications and variations within the spirit and scope of the invention and its equivalents.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an air isolator according to a preferred embodiment of the present invention.

FIG. 2 is a view similar to FIG. 1 showing another feature according to an embodiment of the invention.

[Explanation of symbols]

 10,100 air isolator 15 working piston 16 compliance chamber 18 pressure barrier 20 gas 19 laminar flow

Continuation of the front page (56) References JP-A-62-55207 (JP, A) JP-A-62-24051 (JP, U) JP-A-59-88541 (JP, U) JP-A-61-122435 (JP) U.S. Pat. No. 3,784,146 (US, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16F 9/02 F16F 9/06 F16F 15/02 F16F 15/04

Claims (12)

(57) [Claims] 1. An air damper wherein a working piston is displaced by vibration with respect to a compliance chamber containing a volume of compressed gas predetermined by a natural vibration frequency, wherein the air is displaced by a gas moved by the working piston. A pressure barrier in the compliance chamber that is permeable and overlays the working piston to eliminate the need for an external damping chamber, wherein the pressure barrier is
The working piston is filled with the gas
And a narrow space surrounding it in close proximity from the axial direction.
The air vibration isolator is cut off . 2. The air damper of claim 1 including means for sealing said compliance chamber against said volume of gas leaving said compliance chamber by movement of said working piston. 3. The air isolator according to claim 1, further comprising means for providing a laminar flow to the gas moving through the pressure barrier in the compliance chamber by the working piston. 4. The air vibration isolator according to claim 1, further comprising an acoustic damping material inside the compliance chamber. 5. The air damper according to claim 1, further comprising an acoustic damping material inside the pressure barrier. 6. The air isolator according to claim 1, wherein the pressure barrier is as close to the piston as possible by the travel of the working piston. 7. Means for isolating a horizontal component of vibration coupled to said piston, said pressure barrier being as close to said piston as permitted by the horizontal component of vibration isolation and working piston travel. The air vibration isolator according to claim 6. 8. The air isolator according to claim 6, wherein said piston has a diaphragm seal, and said pressure barrier is as close to said piston as is permitted by operation of said diaphragm seal and operating piston travel. 9. An air isolator according to claim 1, including means for automatic centering of the working piston prior to each expansion of the compliance chamber by the compressed gas. 10. The air isolator of claim 9 including a contoured centering guide on the working piston. 11. A means for sensing the distance of the working piston relative to the pressure barrier, and coupled to the sensing means.
The air isolator according to any one of claims 1 to 10, further comprising valve means for adjusting the pressure of the compressed gas. 12. The air damper of claim 11 including an actuator for said valve means including a link extending in the direction of the working piston travel from said piston to said valve means.