Abstract: An apparatus and method are provided for sealing and electrically coupling an outer surface 170 of a shaft 175 to an inner surface 165 of a hub 160 disposed about the shaft. The invention is particularly useful for spindle motors 155 used in disc drives 100. In one embodiment, a seal 185 having a pair of annular pole pieces 270a, 270b, coupled to opposite poles of a magnet 265 is positioned between the shaft 175 and the hub 160. A nonmagnetic, electrically conductive ring 275 electrically couples the pole pieces 270a, 270b to one another and to the hub 160. In one version, the electrically conductive ring 275 includes an annular disk 300 with tabs 305 projecting from the exterior radius. The disk 300 abuts one pole piece 270b and the tabs 305 are folded over to electrically couple to the other 270a.

Abstract: A hard disk drive spindle motor has a hub, a drive shaft, and a bearing therebetween. The spindle motor also has a ferrofluid seal to prevent any incidental oil emissions from the bearing from entering the drive. A ferrofluid cap is mounted on the axial end of the spindle motor for sealing the ferrofluid seal. The cap is a flat ring and has an elastomeric pad around its outer edge. The pad seats in a recess in the bore of the hub. The cap does not touch the shaft as it rotates with the hub about the shaft. Any excess ferrofluid from the ferrofluid seal is forced radially outward away from the shaft by centrifugal force. The cap contains the excess ferrofluid within the spindle motor and prevents it from entering other areas of the disk drive.

Abstract: A ferrofluid sealing device retaining a ferrofluid between a shaft and a pair of inner and outer pole pieces rotating in opposite directions, in which grooves are formed on a shaft surface that faces the inner diameter surfaces of pole pieces. In the sealing device, one of the pole pieces may be made thicker than the other and further a projection portion can be formed on the shaft surface facing the inner peripheral faces of the pole pieces. The sealing device can prevent, even when the ferrofluid seal is operated at a higher rotation speed, splashing of ferrofluid over the surroundings, thereby avoiding staining the surroundings as well as prolonging its lifetime.

Abstract: A sealing apparatus which is disposed between the media side and the bearing side and adapted to hermetically seal members rotating concentrically relative to each other, wherein a passageway having in a U-shaped cross section is formed by an outer shielding member on the media side, an outer shielding member on the bearing side and an inner shielding member, the end portion of which is inserted into the cavity between the outer shielding members. The end portion of the inner shielding member has a T-shape or L-shape. A magnet is arranged at either the inner shielding member or the outer shielding member. A ferrofluid is retained in the cavity by the surrounding magnet. An oil repellent material may be coated on the surface of the inner shielding member except for a portion extending into the cavity and an adhered portion on its inner diameter side.

Abstract: A magnetic fluid sealing device basically includes a housing; a rotating shaft rotatably supported in said housing by bearings; and a magnet and magnetic pole pieces, which are arranged in such a manner as to encircle said rotating shaft with micro gaps put therebetween. A magnetic field formed by magnet forms magnetic fluid films in the micro gaps to thereby magnetically seal high pressure/vacuum regions positioned at both ends of the rotating shaft. The sealing device is characterized in that the housing, and a mounting cap for fixing the magnetic fluid sealing portion and the bearings at specific positions in the housing are made of a magnetic material, and the materials of the housing and bearing and the dimension of the mounting cap are changed, to thereby reduce a leaked magnetic flux.

Abstract: A seal arrangement (40) between relatively movable components (42,48) includes at least one magnet (54) on a first component (48) and at least one magnet (56) on the second component (42). A clearance (55) is defined between the at least one magnet (54) on the first component (48) and the at least one magnet (56) on the second component (42). Springs (58) bias the at least one magnet (54) on the first component (48) and the at least one magnet (56) on the second component (42) towards each other. The at least one magnet (54) on the first component (42) and the at least one magnet (56) on the second component (42) are arranged to repel each other against the spring (58) to control the clearance (55).

Abstract: A rotary motion feedthrough is described for coupling rotary motion from a rotatable shaft between an atmospheric side to a vacuum side by providing a dynamic magnetic seal of ferrofluid about the shaft using a non-rotating magnetic system formed of a unitary pole piece with magnets contained in radial slots formed in an inner diameter of the pole piece opposite the shaft.

Abstract: A seal assembly includes a seal element having a plurality of movable seal segments and further includes a plurality of actuators, each associated with a respective one of the seal segments. Each of the seal segments has a coil that generates electrical energy in the presence of a varying magnetic field. Each of the actuators receives energy from the associated seal segments and in response thereto produces a force that causes the segment to move toward or away from a surface on an opposing seal member.A method for fabricating a seal element for a gas turbine engine includes providing a wafer, forming seal segments on the wafer, dividing the wafer into a plurality of seal segments, and arranging at least two of the plurality of seal segments into a seal element.

Abstract: A rotation transmitting device 1 introduces rotation into a vacuum side space 200 via a flexible meshing type gear drive 4 from an atmosphere side space 100. A first spacer 15 is disposed between ball bearings 13 and 14 of a rotation output shaft 5 positioned at the vacuum side, and a magnetic circuit is formed passing from the spacer 15 and through the ball bearing 13, a shaft portion 51 of the rotation output shaft 5 and the ball bearing 14. A magnetic fluid is filled as lubricant for lubricating potions of the ball bearings 13 and 14, which is retained on these portions by magnetic force generated by the magnetic circuit, whereby these portions are always lubricated appropriately. The magnetic fluid retained on these portions captures wear particles or other dust generated from the ball bearings 13 and 14, preventing these particles from leaking out to the vacuum side.

Abstract: A motor is disclosed which includes a shaft and a hub rotating relative to one another and defining a bore therebetween. Also disclosed is a magnetic fluid seal which includes pole pieces supported from the hub, the pole pieces extend toward the shaft. The pole pieces sandwich a non-conducting magnet in a space between the pole pieces. In addition, a contacting process is supported from one of the pole pieces for making electrical contact with the other pole piece to enhance electrical conductivity between the hub and shaft.

Abstract: A rotary motion feedthrough for coupling rotary motion from a rotatable shaft between an atmospheric side to a vacuum side includes a dynamic magnetic seal formed of magnets separated by pole rings which rings are formed integral with the shaft to form a magnetic system which rotates with the shaft.

Abstract: A single pole piece magnetic fluid seal apparatus, which includes a shaft sleeve, having magnetic properties, attached to and surrounding a shaft element to be sealed is provided The apparatus also includes single pole piece surrounding the shaft sleeve, proximate to and in non-contacting relationship with the shaft sleeve so as to define a radial gap between the pole piece and the shaft sleeve, The single pole piece includes first and second annular elements attached by a cross piece consisting of a third annular element, wherein the first, second and third annular elements define an annular channel therebetween. The apparatus also includes at least one magnet located within the annular channel and magnetic fluid disposed in the radial gap to provide a seal between the shaft sleeve and the pole piece. The magnet and the single pole piece provide a magnetic flux path through the pole piece, magnet, magnetic shaft sleeve and magnetic fluid.

Abstract: A magnetic fluid sealing device for preventing magnetic fluid from flowing out or spattering under the influence of rotation of a rotatable shaft, thereby preventing contamination of the surroundings. The device includes a pole piece 1 formed with a step portion 13 whose front end surface 4 is disposed more inwardly than the proximal end surface, and the surface of the step portion 13 opposed to a magnetic body 6 serves as a barrier wall 10. Thereby, magnetic fluid 7 is prevented from flowing out or spattering into the surroundings.

Abstract: A magnetic fluid sealing device adapted to enable rotary motion to be coupled by a shaft between an ambient high pressure environment to a high temperature, low pressure environment. Gaps in the shaft are dynamically sealed by a magnetic seal which uses a thin walled pole piece, a high power magnet and magnetic fluid. The pole piece and an extension thereof form a vacuum envelope for the remainder of the device, eliminating the need for the usual O-ring static seals.

Abstract: A rotating sealing device for sealing between a wall separating two mediums under substantially different pressure and a rotatable shaft utilizes a combination of a liquid meatal seal comprising at least one liquid metal ring and a shield means which prevents contamination of the metal ring by gases coming into contact with the liquid metal. Magnetic fluid seal, a ring of an oil material, or inert gas may be used as a shield to protect the liquid metal.