Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Matsushita Electrical Industrial Co., Ltd.

Takafumi Asada

Hiroaki Saito

Keigo Kusaka

Daisuke Ito

Daisuke Itou

Hiroyuki Kiriyama

Masato Morimoto

Hideaki Ohno

Takao Yoshitsugu

Tsutomu Hamada

Takashi Sonoda

Tadao Shioyama

Hiroyuki Funasho

Cyuryo Yoshida

Yoshihiro Ikemoto

Shigeo Obata

Katsunori Sakuragi

Yasuhiro Asaida

Kaoru Uenosono

Tadashi Sakairi

Minoru Koda

Toru Nakagawa

Hideo Matsumoto

Yasuo Saeki

Yosei Yoshikawa

Kouji Nakagawa

Jiro Kataoka

Yoshiteru Hosokawa

Tutomu Hamada

Kazuyoshi Shinohara

Yasunori Tokunou

Hisaaki Yano

Hiroaki Saitoh

Koichi Fujimoto

Kanji Kiyohara

Toshio Onishi

Kajuyoshi Senma

Churyo Yoshida

Kazuyoshi Kurose

Tomoharu Takeda

Hiroyuki Funasyo

Akira Sakata

In a hydrodynamic bearing device with which the lubricant is prevented from leaking to the outside, and good seal performance can be maintained, and in a spindle motor equipped with this hydrodynamic bearing device, the hydrodynamic bearing device includes a shaft, a sleeve, a lubricant that fills a microscopic gap, a radial bearing portion, a thrust bearing portion, and a bearing seal portion. The value of a function P/V, where Vis a fluctuation volume of the sleeve in the axial direction and Pis a capillary pressure index at a vapor-liquid interface located near the opened end of the bearing seal portion, is at least a specific value.

Hydrodynamic bearing device, and spindle motor equipped with same

A hydrodynamic bearing type rotary device includes radial hydrodynamic grooves and thrust hydrodynamic grooves forming communicating channels, communicating holes designed to communicate the groove end of the radial hydrodynamic groove on the side opposite the thrust hydrodynamic grooves with the groove end of the thrust hydrodynamic groove on the side opposite the radial hydrodynamic grooves, and a circulation route composed by the communicating hole, the radial hydrodynamic groove, and the thrust hydrodynamic groove. Lubricating oil is circulated by means of a pump force of the hydrodynamic groove. The hydrodynamic bearing device prevents the formation of low-pressure parts from the bearing portion, preventing the accumulation of air bubbles, and thereby preventing the occurrence of oil film breakage at the radial hydrodynamic groove and the thrust hydrodynamic groove.

Hydrodynamic bearing type rotary device and recording and reproducing apparatus equipped with same

In a hydrodynamic bearing type rotary device, relationships between the number of times of intermittence life, a bearing load, lubricating fluid viscosity, a bearing size, and the like are considered in order to provide a hydrodynamic bearing type rotary device which can secure appropriate intermittence life. In a hydrodynamic bearing type rotary device, a shaft is inserted into a bearing hole of a sleeve so as to be relatively rotatable. A value of a function (Nd) is set to be 100,000 or higher: wherein Nd=&#x3b7;/(S&#xb7;Ff&#xb7;P&#xb7;D).

Hydrodynamic bearing type rotary device

A hydrodynamic bearing type rotary device is configured to prevent air from being trapped inside a bearing and causing the bearing to have oil film rupture and NPPR to deteriorate. In the device, a flange having a shape substantially like a disc is provided integrally with a shaft near its lower portion. A sleeve having a bearing hole is fitted to the shaft so as to be relatively rotatable. Hydrodynamic grooves are provided on at least one of an outer periphery of the shaft and an inner periphery of the sleeve. The flange forms a thrust bearing surface with a lower end surface of the sleeve. Hydrodynamic grooves are provided on at least one of the lower surface of the sleeve and an upper surface of the flange. During rotation of the bearing, the hydrodynamic grooves circulate the lubricant. Capillary pressures at respective portions in the lubricant circulation path have different magnitudes. The principle that air tends to move toward the portion having a smaller capillary pressure is utilized to make it difficult for the air to be trapped inside the bearing and to smoothly discharge the air.

Hydrodynamic bearing type rotary device and recording and reproducing apparatus including the same

A hydrodynamic bearing rotary device which can reduce rotation friction, and recording and reproducing apparatus including the same is provided. In the hydrodynamic bearing rotary device, such as hard disc devices, a rotary shaft having a hub on one end is provided in a bearing of a sleeve so as to be rotatable. Thrust hydrodynamic grooves are provided on the other end surface of the rotary shaft, to form a thrust bearing with the thrust plate. A communication path is provided in the sleeve. The second gap between the hub and the sleeve end surface is used as a flow channel and is connected to the communication path. In this way, the rotation friction torque of the thrust bearing can be made sufficiently small, and internal pressure in bonded portions of the rotary shaft or the bottom plate can be suppressed. Thus, the oil can be prevented from oozing out from a small space of the bonded surfaces. Furthermore, the hydrodynamic bearing can be made thin. These effects can be combined to realize an optimal hydrodynamic bearing rotary device.

Hydrodynamic bearing rotary device and information apparatus

In a hydrodynamic bearing device in which a radial bearing face having a dynamic pressure generating groove on a shaft or an inner periphery of a sleeve is provided and a clearance between the shaft and the sleeve is filled with lubricant, an annular depression is provided on one end face of the sleeve adjacent to a rotor hub and a cover plate for covering the depression is attached to the sleeve so as to define a reservoir for the lubricant or air for the purpose of preventing such a risk that absence of an oil film occurs in clearances of a bearing of the hydrodynamic bearing device due to outflow of oil upon forcing of the oil by air received into the bearing. A step portion is provided on the other end face of the sleeve such that the step portion and the reservoir are communicated with each other by a communication hole. During operation of the hydrodynamic bearing device, air in the hydrodynamic bearing device reaches the reservoir via the communication hole so as to be discharged from the reservoir.

Hydrodynamic bearing device and disk rotation apparatus

To prevent air from being trapped inside a bearing and causing the bearing to have oil film rupture and NRRO to deteriorate. In a hydrodynamic bearing, a first lubricant reservoir is provided in a gap between a lower surface of a hub and a sleeve, and a second lubricant reservoir is provided in a gap between an outer peripheral surface of the sleeve and an inner peripheral surface of the hub or an inner peripheral surface of a stopper member fixed to the hub. If air enters inside such a hydrodynamic bearing, the air has to be discharged. For this purpose, the relationship in widths of the radial bearing gap, the maximum gap of the first lubricant reservoir under the lower surface of the hub and the maximum gap of the second lubricant reservoir on the sleeve outer peripheral surface, or the relationship in magnitudes of capillary forces thereof is adjusted. The principle that air tends to move toward the portion having smaller capillary pressure is utilized to make it difficult for the air to be trapped inside the bearing and to smoothly discharge the air from a gas-liquid interface of the second lubricant reservoir.

Hydrodynamic bearing type rotary device and recording and reproduction apparatus including the same

A hydrodynamic bearing device is provided for use with a spindle motor. The hydrodynamic bearing device has a sleeve made of a sintered metal that is obtained by sintering a sintering material that is iron, an iron alloy, copper, a copper alloy or a mixture thereof. This sintered metal has independent pores, which do not communicate with each other, by selecting conditions for forming a desired sintered body within a predetermined range. The conditions includes a grain size of powdered metal of a material for the sintered metal, a molding pressure when the molded body is formed, sintering temperature and sintering period in the sintering step.

Hydrodynamic bearing device

An object of the present invention is to provide a hydrodynamic bearing type rotary device which can improve rotation performance, suppress a friction torque, and reduce power consumption of motor, and a recording and reproducing apparatus including the same. A shaft having a flange on one end and a hub on the other end is provided with a bearing of a sleeve so as to be rotatable. The sleeve includes a communication hole. A third gap between the hub and the sleeve end surface is a flow path, and is connected to the communication hole. Provided that a first gap between a thrust plateand the flangeis S, a second gap between the flangeand a lower end surface of the sleeveis S, and a third gap between the upper end surface of the sleeveand the hubis S, widths of the gaps satisfy the relational expression, S(S+S).

Hydrodynamic bearing rotary device

Hydrodynamic bearing device and disk rotating apparatus

A hydrodynamic bearing type rotary device which allows bubbles in a lubricating fluid to be surely discharged from a bearing portion is provided. A hydrodynamic bearing mechanismof the hydrodynamic bearing type rotary device is formed of a sleeve, a shaft, a flange, a thrust plate, a seal cap, and oil. A first fluid reservoir F is formed between the sleeve, the flange, and the thrust plate. A second fluid reservoir H is formed between the sleeveand the seal cap. In the sleeve, a communication hole G extending along an axial direction is formed. The first fluid reservoir F and the second fluid reservoir H communicate with each other through the communication hole G. The oilis filled between the members. A capillary pressure is higher in the first fluid reservoir F than in the second fluid reservoir H.

A hydrodynamic bearing device in which an introducing minimum clearance for causing capillary phenomenon is formed from the location in the proximity of the opening of a communicating path to the open end of the bearing hole in between the cover and the end face on the open end of the sleeve so that the operating fluid from the communicating path in the sleeve flows into the bearing hole by the capillary phenomenon; a vent hole leading to the outside air is formed on the cover; a fluid storage space for storing the operating fluid is formed on the inside surface of the cover or the end face on the open end of the sleeve to communicate the introducing minimum clearance and the vent hole in the circumferential direction; and the air bubbles separated at the fluid storage space are exhausted outward from the vent hole.

A high-accuracy, long-life hydrodynamic bearing that does not cause oil film breakage in bearing clearances and a disc rotation apparatus using the bearing is disclosed. Oil film breakage is avoided as negative pressure is prevented from generating between the shaft and sleeve of the hydrodynamic bearing. Herringbone shaped dynamic pressure generating grooves, located on the thrust bearing section and the radial bearing section of the hydrodynamic bearing, are oil filled and have optimum shapes. The optimum shapes prevent the generation negative pressure and thus prevents the coagulation of air bubbles that can cause oil film breakage. The disc rotation apparatus, that holds a reproduction/recording disc, is concentrically secured to the hydrodynamic bearing and rotated. The disc is put into contact with magnetic or optical heads while rotating in the disc rotation apparatus. Both the hydrodynamic bearing and the disc rotation apparatus experience high reliability.

Hydrodynamic bearing and disc rotation apparatus using the same

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Hirakata, Japan

Takafumi Asada