Magnetic fluid pneumatic bearings

Claim 2

A bearing assembly which comprises: a. a housing having an inner surface; b. a pin having an outer surface and received within the housing the outer surface of the pin spaced apart from the inner surface of the housing; c. means to provide a periphery of magnetic flux disposed on one of said surface; d. a first magnetic fluid positioned along said periphery and contacting the other of said surfaces in sealing relationship; e. a bearing pad sealed between the inner and outer surfaces and within the periphery of the magnetic fluid to provide a fluid support pad therebetween; f. means to form a zone of magnetic flux on one of said surfaces, said means external of the periphery of the first magnetic fluid and the bearing pad; and g. a second magnetic fluid positioned at said zone to provide a restoring force in response to a force acting on either the housing and/or the pin.

Claim 3

The bearing of claim 1 wherein the zone includes a plurality of peripheries of magnetic flux disposed on one of said surfaces and wherein magnetic fluid is positioned along each of said peripheries to provide a plurality of ring-like magnetic fluid seals between said surfaces.

Claim 4

The bearing of claim 2 wherein the means to establish the peripheries of magnetic flux include a plurality of annular magnets in combination with pole pieces.

Claim 5

The bearing of claim 3 wherein the pole pieces define annular gaps on said surface.

Claim 6

The bearing of claim 4 wherein said gaps are defined on the outer surface of the pin.

Claim 7

The bearing of claim 4 wherein the gaps are defined on the outer surface of the pin in spaced apart parallel relationship.

Claim 8

The bearing of claim 4 wherein said gaps are defined on the inner surface of the housing.

Claim 9

The bearing assembly of claim 1 wherein either the inner surface of the housing or the outer surface of the pin is a nonmagnetizable surface, and the other surface a magnetic surface, and wherein a magnetic flux passes through the magnetic surface and a magnetic fluid, and returns through another portion of the magnetic surface.

Claim 10

The bearing assembly of claim 1 which includes means to limit the axial movement of the pin within the housing.

Claim 11

The bearing assembly of claim 1 which includes means to provide for pressure equilization within the housing during the assembly of the pin within the housing.

Claim 12

The bearing assembly of claim 1 wherein the housing is characterized by being sealed at one end thereof, and wherein the pin at such end is characterized by a shape to provide a stop at such end when force is applied to the pin, such stop preventing escape of fluid from the fluid-bearing pad.

Claim 13

A bearing assembly which comprises in combination: a. a housing sealed at one end and characterized by an inner surface; b. a pin characterized by an outer surface and positioned within The housing, the outer surface of the pin spaced slightly apart from the inner surface of the housing, the pin and housing adapted for movement relative to one another; c. a plurality of annular magnets and pole pieces disposed on one of the said surfaces to provide a plurality of peripheries of magnetic flux, the magnets and pole pieces defining gaps therebetween; d. a first magnetic fluid positioned along one of the peripheries and contacting the other said surface in a sealing relationship; e. a bearing pad sealed between the inner and outer surfaces, and within the periphery of the first magnetic fluid to provide a fluid-support pad therebetween, the support pad extending about the sealed end of the housing so as to restrain the pin from contacting the sealed end of the housing during normal operation of the bearing; f. a second magnetic fluid positioned along the other peripheries formed by the annular magnets and pole pieces, the second magnetic fluid external of the periphery of the first magnetic fluid and bearing pad, and the second magnetic fluid adapted to provide a restoring force in response to the force acting on either the housing or the pin, or both; g. means to limit axial movement of the pin within the housing; and h. means to provide for pressure equilization between the air in the bearing pad and the external air pressure of the housing during assembly of the pin within the housing, whereby the air-support pad sealed by the first magnetic fluid at the one end of the housing provides for a support of the pin within the housing, while the second magnetic fluid in combination with the first magnetic fluid provides for a restoring force to maintain the position of the pin and housing such that the surfaces do not contact each other during relative movement in respect to each other.

Claim 14

A bearing assembly which comprises in combination: a. a housing sealed at one end and characterized by an inner surface; b. a pin characterized by an outer surface and positioned within The housing, the outer surface of the pin spaced slightly apart from the inner surface of the housing, the pin and housing adapted for movement relative to one another; c. a plurality of annular magnets and pole pieces disposed on one of the said surfaces to provide a plurality of peripheries of magnetic flux, the magnets and pole pieces defining gaps therebetween; d. a first magnetic fluid positioned along one of the peripheries and contacting the other said surface in a sealing relationship; e. a bearing pad sealed between the inner and outer surfaces, and within the periphery of the first magnetic fluid to provide a fluid-support pad therebetween, the support pad extending about the sealed end of the housing so as to restrain the pin from contacting the sealed end of the housing during normal operation of the bearing; f. a second magnetic fluid positioned along the other peripheries formed by the annular magnets and pole pieces, the second magnetic fluid external of the periphery of the first magnetic fluid and bearing pad, and the second magnetic fluid adapted to provide a restoring force in response to the force acting on either the housing or the pin, or both; g. means to limit axial movement of the pin within the housing; and h. means to provide for pressure equilization between the air in the bearing pad and the external air pressure of the housing during assembly of the pin within the housing, whereby the air-support pad sealed by the first magnetic fluid at the one end of the housing provides for a support of the pin within the housing, while the second magnetic fluid in combination with the first magnetic fluid provides for a restoring force to maintain the position of the pin and housing such that the surfaces do not contact each other during relative movement in respect to each other.

Claim 15

The bearing assembly of claim 12 wherein the second magnetic fluid extends in at least one peripheral sealing relationship about the periphery of the pin.

Claim 16

The bearing assembly of claim 12 wherein the end of the pin adjacent the sealed end of the housing includes a head shaped in a convexed manner to function as a mechanical stop when the pin head moves into contact with the sealed end of the housing, thereby preventing an axial force applied to the pin from forcing nonmagnetizable fluid from the support pad.

Claim 17

The bearing assembly of claim 12 which includes a mechanical stop means at one end of the pin and a retaining means at the other end of the pin to limit axial movement of the pin within the housing.

Claim 18

The bearing assembly of claim 12 wherein the means to provide for pressure equilization includes a valve adapted to be open during assembly so as to permit air in the air-support pad entrapped between the inner and outer surfaces of the pin and the housing to be discharged, the valve adapted to be closed after assembly to maintain a sealed air-support pad.

Claim 19

The bearing assembly of claim 12 wherein the inner surface of the housing or the outer surface of the pin comprises a nonmagnetic surface, while the other surface is a magnetic surface, and wherein the magnetic flux from the annular magnets passes through the magnetic surface and the first and second magnetic fluids.

Claim 20

The bearing assembly of claim 12 wherein the means to provide pressure equilization includes a pin characterized by a central air flow passage therein, an air passage at one end of the pin in fluid-flow communication between the central flow passage and the air-support pad and a valve in fluid-flow communication with the central flow passage.

Claim 21

The bearing assembly of claim 12 wherein the plurality of peripheries of magnetic flux are positioned in substantially parallel spaced apart sequential peripheries about the pin to place the second magnetic fluid in a plurality of sealing relationships between the inner and outer surfaces.

Claim 22

A bearing assembly which comprises in combination: a. a housing sealed at one end and characterized by an innEr surface; b. a pin characterized by an outer surface and positioned within the housing, the outer surface of the pin spaced slightly apart from the inner surface of the housing, the pin and housing adapted for movement relative to one another, one of said surfaces being a magnetic surface, and the other of such surfaces being a nonmagnetic surface; c. a plurality of annular magnets and pole pieces disposed on the magnetic surface to provide a plurality of substantially parallel spaced apart peripheries of magnetic flux, the magnets and pole pieces defining gaps therebetween, and defining at least a first magnetic flux periphery and a second magnetic flux periphery; d. a first magnetic fluid positioned along the first magnetic flux periphery and contacting the nonmagnetic surface in a sealing relationship; e. a bearing pad formed and sealed between the inner and outer surfaces along the periphery of the first magnetic fluid formed by said fluid to provide an air-support pad therebetween, the support pad extending and including the sealed end of the housing so as to restrain the pin from contacting the sealed end of the housing during normal operation of the bearing assembly; f. a second magnetic fluid positioned along the second peripheries and contacting the nonmagnetic surface in a plurality of sealing relationships, the second magnetic fluid external of the periphery of the first magnetic fluid and bearing pad, the second magnetic fluid adapted to provide a restoring force in response to the force acting on either the housing or the pin; g. means to limit the axial movement of the pin within the housing; and h. means to provide for equilization of pressure within the pin and the housing during assembly.

Claim 23

A bearing assembly which comprises in combination: a. a housing sealed at one end and characterized by an innEr surface; b. a pin characterized by an outer surface and positioned within the housing, the outer surface of the pin spaced slightly apart from the inner surface of the housing, the pin and housing adapted for movement relative to one another, one of said surfaces being a magnetic surface, and the other of such surfaces being a nonmagnetic surface; c. a plurality of annular magnets and pole pieces disposed on the magnetic surface to provide a plurality of substantially parallel spaced apart peripheries of magnetic flux, the magnets and pole pieces defining gaps therebetween, and defining at least a first magnetic flux periphery and a second magnetic flux periphery; d. a first magnetic fluid positioned along the first magnetic flux periphery and contacting the nonmagnetic surface in a sealing relationship; e. a bearing pad formed and sealed between the inner and outer surfaces along the periphery of the first magnetic fluid formed by said fluid to provide an air-support pad therebetween, the support pad extending and including the sealed end of the housing so as to restrain the pin from contacting the sealed end of the housing during normal operation of the bearing assembly; f. a second magnetic fluid positioned along the second peripheries and contacting the nonmagnetic surface in a plurality of sealing relationships, the second magnetic fluid external of the periphery of the first magnetic fluid and bearing pad, the second magnetic fluid adapted to provide a restoring force in response to the force acting on either the housing or the pin; g. means to limit the axial movement of the pin within the housing; and h. means to provide for equilization of pressure within the pin and the housing during assembly.

Claim 24

A bearing assembly which comprises: a. a first element having a first surface; b. a second element having a second surface spaced apart from and facing the first surface, said surfaces adapted for relative movement in respect to each other, one of said surfaces being magnetic and the other being nonmagnetic; c. a first magnet means on the magnetic surface to provide a first periphery of a first magnetic flux along said magnetic surface; d. a first magnetic fluid positioned along said first periphery, the magnetic fluid contacting the other nonmagnetic surface in a sealing relationship; e. a fluid-bearing pad formed by the first magnetic fluid and the first magnetic flux and sealed between said surfaces and the periphery of the first magnetic fluid; f. a second magnet means on the magnetic surface to provide at least one second periphery of a second magnetic flux along said surface, said second magnetic flux external of the periphery of the first magnetic fluid and the flux; and g. a second magnetic fluid positioned along the second magnetic flux, said second magnetic fluid providing a restoring force when a force acts on either of said surfaces, the peripheries of the first and second magnetic flux passing solely through the magnetic surface and the first and second magnetic fluid.

Claim 25

A bearing assembly which comprises: a. a first element having a first surface; b. a second element having a second surface spaced apart from and facing the first surface, said surfaces adapted for relative movement in respect to each other, one of said surfaces being magnetic and the other being nonmagnetic; c. a first magnet means on the magnetic surface to provide a first periphery of a first magnetic flux along said magnetic surface; d. a first magnetic fluid positioned along said first periphery, the magnetic fluid contacting the other nonmagnetic surface in a sealing relationship; e. a fluid-bearing pad formed by the first magnetic fluid and the first magnetic flux and sealed between said surfaces and the periphery of the first magnetic fluid; f. a second magnet means on the magnetic surface to provide at least one second periphery of a second magnetic flux along said surface, said second magnetic flux external of the periphery of the first magnetic fluid and the flux; and g. a second magnetic fluid positioned along the second magnetic flux, said second magnetic fluid providing a restoring force when a force acts on either of said surfaces, the peripheries of the first and second magnetic flux passing solely through the magnetic surface and the first and second magnetic fluid.

Claim 26

The bearing assembly of claim 21 wherein the second magnetic flux comprises a plurality of magnetic fluxes arranged in a generally parallel spaced apart relationship along said surface, the second magnetic fluid positioned along the second magnetic fluxes and contacting the other surface in a sealing relationship, thereby providing a bearing assembly having a multiseal effect.

Claim 27

The bearing assembly of claim 21 wherein the first and second elements comprise an outer surface of a cylindrical piston and the inner surface of a piston cylinder, the fluidbearing pad sealed within the first magnetic flux and first magnetic fluid encompassing the surface of the piston head.

Claim 28

The bearing assembly of claim 21 wherein the first and second elements comprise elements having extended, but generally parallel, angular surfaces.