Minebea Company, Limited

Minebea Mitsumi Inc.

Hitachi Powdered Metals Co., Ltd.

Tadashi Akahori

Rikuro Obara

Akihiko Suzuki

Katsutoshi Nii

Andreas Kull

Makoto Chonan

Shunichi Togashi

Kazuya Iinuma

A conical bearing member includes a communication hole communicating an inner peripheral surface and an outer peripheral surface of the conical bearing member, and the inner peripheral surface includes a press-fit region in contact with a shaft and an enlarged diameter region having a diameter greater than a diameter of the press-fit region and including an inner opening part of the communication hole. A tapered part having a diameter increasing toward the enlarged diameter region is provided at an end part of the press-fit region on the enlarged diameter region side.

Fluid dynamic bearing, spindle motor, hard disk drive device

A base member serving as a part of a housing of a hard disk drive device. The base member includes a base body being a cast product, a machined surface obtained by machining a part of the base body at a side of an interior of the housing, an impregnating agent filled into a casting cavity exposed at the machined surface, and a coating film covering a surface including the machined surface of the base body.

Base member and method of manufacturing the same, spindle motor, and hard disk drive device

A spindle motor according to an embodiment includes a base plate, a rotor magnet fixed to a rotor assembly positioned at one surface side of the base plate and a magnetic attraction plate fixed at the one surface side of the base plate so as to face the rotor magnet. An opposite area of the base plate facing the magnetic attraction plate includes a coated area covered by an epoxy electric discharge coating film, and the magnetic attraction plate is fixed to the opposite area via at least one of an epoxy adhesive and an acrylic adhesive.

Spindle motor, hard disk drive device, and method of manufacturing spindle motor

A fluid dynamic pressure bearing device includes a shaft member () and a bearing member (), at least one of the shaft member or the bearing member being rotatable with respect to the other. A shaft member-side annular member () is fixed with respect to the shaft member. The shaft member-side annular member includes a large-diameter rim portion and a small-diameter outer circumferential surface portion. A bearing member-side annular member () is fixed with respect to the bearing member. The bearing member-side annular member includes an inner circumferential large-diameter step portion, and a small-diameter inner circumferential surface portion. A plurality of convex surface portions are formed either on a surface of the inner circumferential large-diameter step portion facing the large-diameter rim portion of the shaft member-side annular member, or on a surface of the large-diameter rim portion of the shaft member-side annular member facing a surface of the inner circumferential large-diameter step portion. A reflux groove () surrounds the convex surface portions.

Fluid dynamic pressure bearing device, spindle motor provided with the fluid dynamic pressure bearing device, and recording disk drive device

A fluid dynamic bearing mechanism for a motor () suitable for use in a hard disk drive and having a compact and thin shape, high bearing rigidity, and high rotating accuracy, and which securely keeps the rotor member () in place against shocks, and allows the inspection of lubricant supply amount easily. A fluid dynamic bearing mechanism having a capillary seal part () on one end of lubricant supply part formed by a minute gap including dynamic pressure grooves () formed on a shaft member () or a bearing member () is provided. An annular member () is fitted on the shaft member at the location corresponding to the capillary seal part, another annular member () is fitted on the bearing member at the location corresponding to the capillary seal part, a taper or step () is formed on the outer peripheral surface of the annular member on the shaft member side and the inner peripheral surface of the annular member on the bearing member side. These inner and outer peripheral surfaces are arranged to be close to and facing with each other so that the rotor member is prevented from disengaging from the bearing member, and the capillary seal part can be formed at the same time. An axial dynamic pressure bearing unit () is formed between the annular member on the shaft member side and one end of the bearing member.

Fluid dynamic bearing mechanism for a motor

A production method for sintered bearing member comprises: compacting a metal powder into a green compact, sintering the green compact into a sintered compact; impregnating a resin solvent into the sintered compact, and removing the resin solvent adhering to a surface of the sintered compact, thereby exposing a matrix as sintered on a surface of the sintered compact. Pores existing in portions other than the surface are sealed with the resin.

Production method for sintered bearing member, fluid dynamic pressure bearing device, and spindle motor

A hydrodynamic bearing system, particularly for the rotary bearing of spindle motors to power hard disk drives. The bearing system includes a bearing sleeve, a shaft accommodated in an opening in the bearing sleeve and at least one radial bearing section provided between the bearing sleeve and the shaft with the aid of which the shaft and the bearing sleeve are supported rotatably in relation to each other. A bearing gap is formed between the shaft and the bearing sleeve and is filled with a liquid lubricant. A lubricant reservoir and equalizing volume independent from the design of the bearing arrangement is provided in that at least one duct is formed in the bearing sleeve that extends from an outer section of the bearing sleeve to the bearing gap and that is at least partially filled with lubricant.

Hydrodynamic bearing system for a rotary bearing of spindle motors

In an outer rotor type spindle motor for driving a disc with a relatively long axial dimension for mounting a large number of the discs, it is possible to reduce part cost and assembling work cost while increasing a rotational precision. The stator is disposed on an opening surface of a drum portion of the rotor rather than between a pair of bearings within the drum portion. The stator coil end may be led to the outside of the drum portion without passing through the bearing to dispense with the conventional works such as a processing of a shaft, an insertion of a lead wire through a tubular hole and the like. Also, a bush between the drum portion and the bearing, which conventionally causes the degradation of the rotational precision and the increases in the cost for the parts and the assembling work, is dispensed with. In order to elongate the distance between the bearings and reduce the axial direction of the stator, a magnet material having a magnetic energy product that is higher than that generally used to this type of motor is selected.

Spindle motor for driving disc

In a spindle motor in which its weight is decreased while maintaining the rigidity of a bearing to a large value, the widthwise dimension of a bearing cartridge assembly is set so that the upper outer ring end portion of the outer ring of the bearing cartridge assembly protrudes from a hub main body A. Since the lengthwise dimension of a hub A is smaller than that of a prior art, the weight and cost can be decreased that much. Further, the lengthwise dimension of the hub A is smaller than that of the prior art, a space portion is increased and the space portion can be employed as a space for arranging various kinds of members. Since the upper outer ring end portion protrudes from the hub main body A, fitting pressure is not exerted on the upper outer ring end portion of the outer ring 12 upon fitting, so that the generation of unnecessary deformation or the like can be avoided.

Growing community of inventors

Kitasaku-gun, Japan

Tadashi Akahori