摘要:
A fluid dynamic bearing apparatus includes a first minute gap, a second minute gap, a third minute gap, a fourth minute gap, and a fifth minute gap. A flow of a lubricating oil from the fifth minute gap to the fourth minute gap is caused by a plurality of dynamic pressure generating grooves arranged within the fluid dynamic bearing apparatus. This flow causes air bubbles mixed in the lubricating oil within the fifth minute gap to flow toward the third minute gap and be discharged to an outside through the third minute gap. In addition, a flow of the lubricating oil into the third minute gap caused by a centrifugal force accompanying rotation is inhibited.
摘要:
A fluid dynamic bearing apparatus includes a first minute gap, a second minute gap, a third minute gap, a fourth minute gap, and a fifth minute gap. A flow of a lubricating oil from the fifth minute gap to the fourth minute gap is caused by a plurality of dynamic pressure generating grooves arranged within the fluid dynamic bearing apparatus. This flow causes air bubbles mixed in the lubricating oil within the fifth minute gap to flow toward the third minute gap and be discharged to an outside through the third minute gap. In addition, a flow of the lubricating oil into the third minute gap caused by a centrifugal force accompanying rotation is inhibited.
摘要:
In a fluid dynamic bearing apparatus, an oil buffer is defined between a thrust gap and a pumping gap. The oil buffer has an axial dimension greater than that of the thrust gap, and/or has a radial dimension greater than that of the pumping gap. An air bubble generated in the thrust gap due to cavitation, for example, when a fluid dynamic bearing apparatus experiences a vibration can be dissolved in lubricating oil provided within the oil buffer. This prevents leakage of the lubricating oil due to the air bubble residing in the fluid dynamic bearing apparatus.
摘要:
A fluid dynamic bearing mechanism includes a stationary bearing portion including a sleeve portion, and a rotating bearing portion including an outer rotating portion. A lubricating oil is arranged between the stationary and rotating bearing portions. A first dynamic pressure groove array is arranged in an upper surface of the sleeve portion or a lower surface of the outer rotating portion. A second dynamic pressure groove array is arranged in a surface of the outer rotating portion or a surface of the stationary bearing portion in a region between the first array and a liquid surface. An end of the second array closer to the liquid surface is arranged radially inward of an opposite end of the second array. An upper end opening of a communicating channel defined in the sleeve portion is arranged radially outward of a radially inner end of the first array.
摘要:
In a motor, a stationary portion includes a shaft portion and an upper thrust portion arranged to define a single continuous monolithic member together with the shaft portion, and arranged to extend radially outward from an upper portion of the shaft portion. The shaft portion includes a female screw portion recessed axially downward from an upper end thereof. An upper end of the single continuous monolithic member defined by the shaft portion and the upper thrust portion includes an upper end annular surface arranged to extend radially outward from the female screw portion perpendicularly or substantially perpendicularly to the central axis. An outside diameter of the upper end annular surface is greater than a diameter of an outer circumferential surface of the shaft portion.
摘要:
A hydrodynamic bearing device comprises a shaft bush having a substantially conical inclined dynamic pressure surface around the outer circumference thereof which is relatively rotatably inserted in a bearing sleeve having a substantially conical inclined dynamic pressure surface around the inner circumference thereof. A substantially conical inclined bearing space is created in the gap between the inclined dynamic pressure surfaces of the bearing sleeve and shaft bush. Lubricant fluid is filled inside the inclined bearing space. A proper dynamic pressure generating means is formed on at least one of the inclined dynamic pressure surfaces of the shaft bush and bearing sleeve. The lubricant fluid is pressurized by the dynamic pressure generating means to generate dynamic pressure, by which the shaft bush and the bearing sleeve are relatively elevated in the radial and thrust directions so that their rotations are supported in a non-contact manner. A fluid sealing portion is provided in the inclined bearing space to prevent the lubricant fluid from leaking outside of the inclined bearing space. A fluid pressurizing means is provided between the inclined bearing space and the fluid sealing portion to pressurize the lubricant fluid in the direction to push it toward the inside of the inclined bearing space.
摘要:
A dynamic pressure bearing is defined in a first gap between a shaft portion and a sleeve portion. An upper seal portion extending upward and a lower seal portion extending downward are arranged radially outward of the dynamic pressure bearing. Each of the upper seal portion and the lower seal portion includes a surface including a lubricating oil located therein. The upper seal portion and the lower seal portion are arranged in communication with each other through a communicating hole defined in the sleeve portion. The communicating hole and a space ranging from the upper seal portion to the lower seal portion through the first gap are filled with the lubricating oil. The axial distance between the surfaces of the lubricating oil in the upper seal portion and the lower seal portion is arranged to be shorter than the axial distance between an upper end and a lower end of the dynamic pressure bearing.
摘要:
A bearing apparatus includes a shaft, a thrust cup including an annular potion and a cylindrical portion, a rotating member including a through hole defined therein, and a lubricating oil. A second gap defined between a lower surface of the rotating member and an upper surface of the annular portion of the thrust cup includes a first region in communication with a capillary seal portion, and a second region positioned radially inward of the first region and having an axial dimension smaller than that of the first region. A lower end portion of the through hole is open at a location radially outwardly away from a boundary between the first and second regions, so that a local circulation of the lubricating oil arises within the first region during rotation of the rotating member.
摘要:
A motor includes a stationary portion and a rotating portion. The rotating portion includes a sleeve portion. The sleeve portion includes a communicating hole. A dynamic pressure bearing is defined in a first gap between a shaft portion and the sleeve portion. An upper seal portion and a lower seal portion are arranged radially outward of the dynamic pressure bearing. The upper seal portion and the lower seal portion are arranged in communication with each other through the communicating hole. The communicating hole and a space extending from the upper seal portion to the lower seal portion through the first gap are filled with a lubricating oil. A fixing region where an outer tubular portion and a base portion are fixed to each other is arranged to overlap with the dynamic pressure bearing in a radial direction in plan view.
摘要:
In a motor, an annular radially extending gap is defined between an outer annular surface and a lower surface of an annular cover portion. The radially extending gap has an axial width smaller than a maximum width of an upper seal portion defined between an outer circumferential surface of an upper thrust portion and an inner circumferential surface of a tubular portion. An annular axially extending gap is defined between an inner cylindrical surface and a radially inner edge of the annular cover portion. The axially extending gap has a radial width smaller than the maximum width of the upper seal portion.