JPH01321417A - Vibration separation and attenuator - Google Patents

Abstract

PURPOSE: To provide a vibration separating and attenuating device for a device having a low vibration specification by constituting the device of bellows, coil springs and fluid removed from its frictional face and Coulomb force and providing the device with stiffness independent of a vibration level. CONSTITUTION: An interval between the end part chip 15 of 1st bellows 13 and the base chip 19 of 2nd bellows 17 is held at a fixed length by a shaft 21 and the whole capacity is held at a fixed value. Thereby fluid with fixed volume contained in two fluid rooms 33, 35 and a gap 27 is distributed to the fluid rooms 33, 35 in accordance with the movement of load. An attenuation factor is changed as the function of the viscosity of the fluid and the radius direction length of the gap 27 so that the value is increased in accordance with the increment of the viscosity and the shortening of the radius direction length. Springs 37, 43, 59 wound around the bellows 13, 17 support a frange and provide the vibration separating device with stiffness. Consequently, the vibration separating and attenuating device for a device having an extremely low vibration specification is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the field of vibration isolation, and more particularly to a vibration isolation and attenuation device for equipment with extremely low vibration specifications. .

[Conventional technology]

The reaction wheel assembly in the orientation control system is an important element of the telephoto system. However, these assemblies contribute significantly to the vibrational component to the device during operation. Because telescopes require strict orientation, it is necessary to isolate or isolate the vibrations caused by the reaction wheels. Most of the vibration is caused by external forces due to the support of the ball in the inner and outer races and imperfections in the ball itself.

One conventional solution to this problem, known as wire rope, is coiled in a circle and attached at one end to a base or earth and at the other end to the equipment or payload to be separated. Make use of several woven wires.

The flexibility of the wires achieves separation and compliance, and the wires rubbing together provide Coulomb damping or energy absorption. The device has low damping and stiffness characteristics (which vary with the magnitude of the input vibration level), performance changes due to environmental changes, and repeated design and testing to arrive at the final configuration. There are some drawbacks, including the mathematical complexity that it requires.

A second conventional solution utilizes a viscous elastic material as the separation element. Although these devices can isolate vibrations in most applications, they are sensitive to changes in temperature and other environmental conditions.

[Summary of the invention]

In accordance with the present invention, vibration isolation and damping is provided by a device comprising a bellows, a coil spring, and a fluid that eliminates friction surfaces and eliminates Coulomb forces, providing stiffness that is independent of vibration level. A first bellows and a second bellows are positioned in axial alignment and fluidly sealed at opposite ends by the end piece and the pace to define an inner chamber. A shaft extending along a common axis is attached to the end piece and the base to maintain a fixed separation distance between the end piece and the pace. A piston having an axial bore and, in fact, a 7 lange extending therefrom for coupling to a dynamic load, is positioned around the shaft in coaxial relation with the shaft to form a fluid gap therebetween. do. The fluid gap is defined by a first bellows formed between the piston, an interior wall of the bellows, and a seven flange extension from the piston with the previously unsealed end of the bellows sealed and containing fluid. and the fluid chamber of the second bellows. Structure B eliminates the Coulomb surface by attenuating the shear force of a purely viscous fluid and completely avoiding friction surfaces. The fluid is sealed in the two fluid chambers and in the gap formed between the piston and the shaft. As the effective load moves, the volume of one fluid chamber increases and the volume of the other fluid chamber decreases. Since the distance between the end piece of the first bellows and the base piece of the second bellows is kept constant by the shaft, the overall volume remains constant. Thus, a constant volume of fluid contained within the two fluid chambers and the gap is distributed to the fluid chambers according to the movement of the load. The damping rate in the present invention varies as a function of the viscosity of the fluid and the radial length of the gap, with higher viscosity (higher viscosity) and lower radial length (lower radial length). A spring wrapped around the bellows supports the seven lunges and provides stiffness to the vibration isolator.

Temperature compensation is provided by providing a third bellows coaxially aligned with the first and second bellows. A fluid chamber is provided inside the third bellows. The fluid chamber is coupled to the first and second bellows fluid systems to provide fluid exchange between the temperature compensator and the main vibration separator. The fluid exchange maintains a constant fluid pressure in the fluid system even when the temperature changes.

A spring wrapped around the temperature compensating bellows maintains an axial force applied to the bellows to apply positive pressure to the fluid over a temperature range independent of environmental pressure.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

Referring first to FIG. 1, vibration isolation and dampener 10 includes a cover 17 surrounding upper bellows 13. As shown in FIG.

An end piece 15 is joined to one end of the bellows to provide a fluid seal and provide structural reinforcement.

A lower bellows 17 with a base piece 19 joined to one end to increase fluid sealing and structural strength is connected to the upper bellows 17.
They are positioned in alignment in the 1-+ line direction. The wall thickness of each bellows can be 75 microns and is curved with electroplating. A sturdy Lat 121 coaxial with the upper and lower bellows is joined to the end piece 15 and base piece 19 to maintain a constant distance therebetween, thereby providing a constant volume within the bellows assembly. A piston 23 having an axial bore and a flange 25 is positioned coaxially around the shaft 21, forming a radial gap 27 therebetween. The part of the upper bellows 13 on the side opposite to the side to which the end piece 15 is joined is joined to the upper surface 29 of the flange extension of the piston, and the base piece 19 of the lower bellows 17 is joined to the upper surface 29 of the flange extension of the piston.
is joined to the lower surface 31 of the 7-lange extension.

An upper fluid reservoir 33 and a lower fluid reservoir 35 are formed by the combination of the flange extension and the upper bellows and the outer surface of the piston wall and the lower bellows, respectively. Fluids that can use Dow Corning's 200 series silicone include Fluid Reservoir 33.3
5 and the gap 27 is completely filled into the device.

This fluid flows through the damping gap 27 into the fluid reservoir 33 during vibration.
and 35. Although the volumes of the fluid reservoirs 33 and 35 may change depending on the movement of the effective load attached to the 7 langes, a constant distance is maintained between the end piece 15 and the pace piece 190 by the shaft 21. The total volume of the fluid reservoir remains constant. Therefore, the effective load and 7 lunge 2
The movement due to 5 is equal in fluid reservoirs 33 and 35, but
An opposite volume change must occur.

An upper spring 37 made of stainless steel is wrapped around the outer surface of the upper bellows 13 between the upper surface 39 of the flange extension 25 and the spring retainer bolted to the end piece 15. On the outer surface of the lower bellows 17, the lower surface 45 of the seven-lunge extension and the skirt 49 which also extends from the base piece 19.
A lower spring 43 made of stainless steel is wound between the spring retainer surface 47 formed in the lower spring 43 and the lower spring 43 made of stainless steel. Those springs are
Provide adequate radial and axial stiffness to vibration damping and isolation devices.

Refer now to FIG. This figure shows how the end piece 15 and the base piece 19 are separated by a fixed distance by a solid shaft 21. A piston 23 having an axial bore is positioned coaxially around the shaft 21 . A flange 25 extends from the piston for attachment to a load. An upper bellows 13 is joined to the end piece 15 and the upper surface 29 of the flange extension, and a lower bellows 17 is joined to the base piece 19 and the lower surface 31 of the flange extension.

an end piece 15, a base piece 19, an upper bellows 13,
It is clear from FIG. 2 that the total volume of fluid contained between the lower bellows 17 is constant.

When an upward force is applied to the pace piece 1, the lower fluid reservoir 3
Assume that the volume of 5 is decreased. 887 of the upper fluid reservoir 33 is then increased and fluid flows from the lower fluid reservoir 35 through the damping gap 27 to the upper fluid reservoir 33,
7 Equalizes the force applied to the top and bottom surfaces of the flange extension, keeping the flange stationary.

Referring again to FIG. Compensation for changes in fluid volume with temperature is achieved by coupling a temperature compensating bellows 51 to the upper bellows 13 via a relief gap 53 and a fluid passageway 55. A fluid seal is provided by the cap 57 and the internal area of the bellows 51, and the temperature compensation relief gap 53 and fluid passageway 55 are filled with fluid to eliminate any voids in the device. A "0" ring 58 between temperature compensating bellows 51 and upper bellows 13 completes the fluid seal. As the temperature rises and the fluid expands, the temperature compensation bellows 51 expands, thereby removing the oversized kings in the fluid reservoirs 33, 35 and damping gaps 27 of the vibration damping and isolation device, thereby reducing the pressure in the device. It is kept constant.

A stainless steel preload spring 59 constantly applies an axial force to the temperature compensating bellows 51 to apply positive pressure to the internal fluid over a wide range of atmospheric pressure conditions. A lower retainer 61 that is coupled to the cap 5T and bolted to the spring retainer 41, and an upper retainer that extends above the lower retainer by a predetermined distance and is bolted to the spring retainer 41. 63 and spring 59 is held in place.

[Brief explanation of the drawing]

FIG. 1 is a cutaway perspective view of the vibration damping and isolation device of the present invention including temperature compensation features, and FIG. 2 is a schematic illustration of the vibration damping and isolation device shown in FIG. 13.17@--Bellows, 15... End piece, 1
9...Base piece, 21...Shaft, 23...Piston, 25...Flange extension, 2T...Gap, 33.35...Fluid chamber, 37, 43.59...
...Spring, 61.63...Spring retainer. Patent Applicant Honeywael Inc. Sub-Agent Masaaki Yamakawa (and 2 others)

Claims (1)

[Claims] a first bellows (13) having a first end and a second end, with the end piece (15) forming a fluid seal, and a first end with the base piece (19) forming a fluid seal; and a second bellows (17) having a second end and located coaxially with the first bellows and the second bellows (13, 17), said end (15) and said base piece. (21) of a predetermined length coupled to (19), thereby maintaining a fixed predetermined gap between them; an axial hole formed between the second end of the first bellows (13) and the second bellows (13);
17) said flange having flange means coupled to said second end of said vibration isolation and damping device to an effective load so as to provide a fluid seal with said first bellows and said second bellows; Extension (25)
forming a first fluid chamber together with the first bellows (13), forming a second fluid chamber (35) together with the second bellows (17), and forming a second fluid chamber (35) with the first bellows (17); 33
) and the second fluid chamber (35), which together with the shaft (21) form a radial gap (27); 2 fluid chambers (35) and said radial gap (27)
said flange extension (25) to have radial stiffness and axial stiffness.
and between the end piece (15) and between the flange extension (25) and the base piece (19);
the first bellows (13) and the second bellows (1
spring means (37, 43) wrapped around the radial gap (27) and into the second fluid chamber (33) and into the second fluid chamber (35); a temperature-compensating bellows (51) having an internal chamber coupled thereto; pressure means (51) coupled to said temperature-compensating bellows (51) for applying a positive pressure to said fluid under conditions of varying atmospheric pressure;
59, 61, 63), and the temperature compensation bellows (
51) expands with the expansion of the fluid and cooperates with the pressure means (59) to maintain a constant device pressure.