The shaft seal device includes a seal cover formed in a tubular shaped and provided on an outer periphery of a rotation shaft which is inserted into an axial hole of a housing, a flexible member that connects the seal cover to the housing, an auxiliary seal portion provided on an interior side of the shaft seal device in an axial direction of the seal cover, a magnetic fluid seal portion provided on an exterior side of the shaft seal device from the auxiliary seal portion in the axial direction of the seal cover, and bearings that support a load of the magnetic fluid seal portion.

A bearing ring having a main part ring provided with at least one groove formed a surface of the main part ring. The bearing ring further provides at least one fiber sensor mounted inside the groove. The bearing ring also include at least one counterpart ring mounted into the groove of the main part ring and coming into contact with the fiber sensor to maintain the fiber sensor against a groove bottom, the counterpart ring being secured to the main part ring.

An electric motor is provided which is designed to minimize a risk of corrosion or stress corrosion cracking of parts thereof and reduce mechanical vibration or noise. The electric motor includes an output shaft, a bearing which retains the output shaft, a frame, and a biasing member. The biasing member is made of austenite stainless steel and disposed between the bearing and a bottom wall of a bearing housing to elastically press the output shaft in a lengthwise direction thereof for eliminating mechanical noise arising from vibration of a rotor. The frame has a coating formed on an outer surface thereof for avoiding erosion thereof. The coating is not formed at least on a portion of the frame which faces the biasing member in order to induce sacrificial corrosion of the frame, which decelerates the corrosion of the biasing member to eliminate a risk of the stress corrosion cracking thereof.

An electric motor is provided which is designed to minimize a risk of corrosion or stress corrosion cracking of parts thereof and reduce mechanical vibration or noise. The electric motor includes an output shaft, a bearing which retains the output shaft, a frame, and a biasing member. The biasing member is made of austenite stainless steel and disposed between the bearing and a bottom wall of a bearing housing to elastically press the output shaft in a lengthwise direction thereof for eliminating mechanical noise arising from vibration of a rotor. The frame has a coating formed on an outer surface thereof for avoiding erosion thereof. The coating is not formed at least on a portion of the frame which faces the biasing member in order to induce sacrificial corrosion of the frame, which decelerates the corrosion of the biasing member to eliminate a risk of the stress corrosion cracking thereof.

A sealing device employing a magnetic fluid for sealing off a vacuum side and an atmosphere side includes two rolling bearings disposed on both sides of the magnetic fluid seal. The magnetic fluid fills the lubrication part of the rolling bearing disposed toward the vacuum side and a magnet is attached to the outer ring toward the vacuum side of said rolling bearing. A ring-shaped yoke formed from a magnetic material and freely fitting into a rotation shaft is attached to the side of the magnet opposite the outer ring of the rolling bearing.

A sealing device employing a magnetic fluid for sealing off a vacuum side and an atmosphere side includes two rolling bearings disposed on both sides of the magnetic fluid seal. The magnetic fluid fills the lubrication part of the rolling bearing disposed toward the vacuum side and a magnet is attached to the outer ring toward the vacuum side of said rolling bearing. A ring-shaped yoke formed from a magnetic material and freely fitting into a rotation shaft is attached to the side of the magnet opposite the outer ring of the rolling bearing.

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.

It is an object of the present invention to more reliably prevent foreign matter from floating in the bearing space of a rolling bearing, while maintaining lubrication performance in the rolling bearing. In order to achieve this object, a rolling bearing is provided which includes an outer race, an inner race, rolling elements mounted between the outer race and the inner race, a seal ring formed with an oil passage hole, and covering at least one of the axial end openings of the bearing space of the bearing, a filter mounted to the seal ring so as to cover the oil passage hole of the seal ring, and configured to catch foreign matter contained in lubricant oil, and a magnetic member mounted axially inwardly of, and adjacent to, the filter, and configured to attract foreign matter to the magnetic member due to the magnetic force of the magnetic member.

A magnetic fluid sealing device includes: a housing; a shaft rotatably penetrating through the housing; a first shaft sleeve made of a magnetic conductive material, and fitted over the shaft; a plurality of pole shoes arranged in the housing and fitted over the shaft and the first shaft sleeve, an inner circumferential surface of the pole shoe being provided with a plurality of pole teeth arranged at intervals in an axial direction of the shaft, the shaft and a first part of the plurality of pole teeth being arranged at intervals in a radial direction of the shaft to form a first gap, the first shaft sleeve and a second part of the plurality of pole teeth being arranged at intervals in the radial direction of the shaft to form a second gap; and a permanent magnet arranged in the housing and fitted over the shaft.

A bearing ring having a main part ring provided with at least one groove formed a surface of the main part ring. The bearing ring further provides at least one fiber sensor mounted inside the groove. The bearing ring also include at least one counterpart ring mounted into the groove of the main part ring and coming into contact with the fiber sensor to maintain the fiber sensor against a groove bottom, the counterpart ring being secured to the main part ring.