The present disclosure discloses a magnetic liquid sealing device adapted to axial and radial displacements of connection, which includes: an end cover; a rubber-sealing-ring equipped first clamping plate fixed on the end cover by a first screw and a second screw; a rubber-sealing-ring equipped second clamping plate installed in a groove of the end cover; a fundamental sealing structure fixed on the rubber-sealing-ring equipped second clamping plate by a third screw and a fourth screw, so as to be isolated from the end cover by the rubber-sealing-ring equipped first clamping plate and the rubber-sealing-ring equipped second clamping plate. The device isolates the connected component from the magnetic liquid sealing structure by the two clamping plates, such that the axial and radial deformations and displacements of the connected component will not be loaded on parts in magnetic liquid sealing structure, prolonging the service life of the magnetic liquid sealing.

In order to determine information about the generation of heat in a bearing (10) in a simple manner, a bearing (10) includes an outer ring (12) secured to a securing member, and an inner ring (11) provided on the inside of the outer ring (12) and secured to a shaft that rotates in the circumferential direction relative to the securing member. A thermal flow sensor (14) is provided as a coating on a securing-side surface that includes the outer ring (12), and generates a thermoelectromotive force including information about frictional heat generated with the rotation of the shaft.

Provided is a magnetic fluid sealed bearing unit that provides excellent handling ease and workability in incorporating the bearing unit into a rotary shaft portion and exhibits a stable sealing capability. A magnetic fluid sealed bearing unit of the present invention has an inner ring and an outer ring, each made of a magnetic material, a plurality of rolling members interposed between the inner ring and the outer ring, a magnetic seal mechanism arranged between the inner ring and the outer ring and configured to inhibit entry of foreign substances toward the plurality of rolling members, a non-magnetic inner ring-side support member fitted and retained on the inner ring, and a non-magnetic outer ring-side support member fitted and retained on the outer ring.

Provided is a magnetic fluid sealed bearing having a stable sealing performance in a gap. The magnetic fluid sealed bearing includes: an inner ring and an outer ring; a plurality of rolling elements disposed between the inner and outer rings; a ring-shaped polar plate mounted on an inner circumferential surface of the outer ring such that a gap is formed between the ring-shaped polar plate and an outer circumferential surface of the inner ring; a ring-shaped magnet attached to the ring-shaped polar plate and magnetized such that magnetic poles thereof point to axial directions, to form magnetic circuits on both an outer ring side and an inner ring side; an inner ring magnetic fluid retained in the magnetic circuit on the inner ring side; and a magnetic field intensity increasing portion for increasing magnetic field intensity of the magnetic circuit on the inner ring side.

One object is to provide a magnetic fluid sealing device in which a magnetic fluid retained between a polar plate and a drive portion can be effectively prevented from spilling, so as to retain waterproofness for a long period. A magnetic fluid sealing device of the present invention includes a ring-shaped polar plate encircling a drive portion and retaining a magnet; and a magnetic fluid retained in a gap between the drive portion and the polar plate by a magnetic force of the magnet. The polar plate has a spill preventing portion provided thereon, the spill preventing portion having a projecting wall that is disposed distant from an end surface of the polar plate retaining the magnetic fluid, so as to prevent spill of the magnetic fluid.

A magnetic fluid seal includes an outer cylinder member with a heat barrier that internally houses a rotating shaft extending from a housing of a fluid machine and includes an attachment portion to be attached to the housing, magnetic pole members that are disposed around the rotating shaft housed in the outer cylinder member and form a magnetic circuit, and sealing films that are magnetically connected to the magnetic circuit, are respectively disposed between the magnetic pole members and the rotating shaft, are made of magnetic fluids, and are formed in an axial direction.

One object is to provide a magnetic fluid sealing device in which a magnetic fluid retained between a polar plate and a drive portion can be effectively prevented from spilling, so as to retain waterproofness for a long period. A magnetic fluid sealing device of the present invention includes a ring-shaped polar plate encircling a drive portion and retaining a magnet and a magnetic fluid retained in a gap between the drive portion and the polar plate by a magnetic force of the magnet. The polar plate has a spill preventing portion provided thereon, the spill preventing portion having a projecting wall that is disposed distant from an end surface of the polar plate retaining the magnetic fluid, so as to prevent spill of the magnetic fluid.

Provided is a magnetic fluid sealed bearing having a stable sealing performance in a gap. The magnetic fluid sealed bearing includes: an inner ring and an outer ring; a plurality of rolling elements disposed between the inner and outer rings; a ring-shaped polar plate mounted on an inner circumferential surface of the outer ring such that a gap is formed between the ring-shaped polar plate and an outer circumferential surface of the inner ring; a ring-shaped magnet attached to the ring-shaped polar plate and magnetized such that magnetic poles thereof point to axial directions, to form magnetic circuits on both an outer ring side and an inner ring side; an inner ring magnetic fluid retained in the magnetic circuit on the inner ring side; and a magnetic field intensity increasing portion for increasing magnetic field intensity of the magnetic circuit on the inner ring side.

A magnetic fluid sealing structure (1) for high-speed rotation for sealing a gap (S) between a shaft member (2) and a housing member (3) disposed around the shaft member (2), which are rotatable, includes: magnetic force generating means (4) which is fixed to the housing member (3) and generates a magnetic force; magnetic pole members (5) disposed on both sides in an axial direction of the magnetic force generating means (4); and a magnetic fluid (7) which is magnetically held between the magnetic pole members (5) and the shaft member (2) by the magnetic force of the magnetic force generating means (4) and seals the gap (S) therebetween, in which the shaft member (2) has a plurality of different material layers concentrically laminated in a radial direction, and an outermost diameter layer (23) of the shaft member (2), which holds the magnetic fluid (7), is made of a magnetic material.

A magnetic fluid seal includes an outer cylinder member with a heat barrier that internally houses a rotating shaft extending from a housing of a fluid machine and includes an attachment portion to be attached to the housing, magnetic pole members that are disposed around the rotating shaft housed in the outer cylinder member and form a magnetic circuit, and sealing films that are magnetically connected to the magnetic circuit, are respectively disposed between the magnetic pole members and the rotating shaft, are made of magnetic fluids, and are formed in an axial direction.