Abstract: With a hydrodynamic bearing device 10, a first gap G1 is formed between a shaft 12 and a sleeve 11. A second gap G2 is formed between a sleeve cap 16 and the sleeve 11, and holds a lubricant 17. A thrust bearing member 21 is disposed near the inner peripheral surface of a center hole 16a of the sleeve cap 16. A third gap G3 is formed between the thrust bearing member 21 and the sleeve cap 16, and is open to the atmosphere. A fourth gap G4 is formed between the thrust bearing member 21 and the sleeve 11. The lubricant 17 circulates along a circulation passage that includes a communicating path 11b, the first gap G1 and the second gap G2.

Abstract: In order to prevent oil leakage in a hydrodynamic bearing device comprising an opening section in close proximity to a radial bearing and a lubricating fluid reservoir, a shaft 10, thrust flange 16, sleeve 11, seal plate 21, and stopper plate 20 are provided, a radial dynamic pressure bearing is formed in a radial clearance between the shaft 10 and sleeve 11, and a thrust dynamic pressure bearing is formed in a thrust direction clearance between the sleeve 11 and thrust flange 16. A connecting hole 11d is formed that connects a gap between the sleeve 11 and seal plate 21 and a thrust direction gap between the sleeve 11 and thrust flange 16. The relationship A<B<C is satisfied, where A is a radial clearance, B is a clearance between an outer peripheral surface of the shaft 10 and an inner peripheral surface of the seal plate 21, and C is a clearance between a lower surface of the seal plate 21 and an upper end face of the sleeve 11.

Abstract: With a spindle motor, a stator core comprises a plurality of salient pole portions that are formed in a radial shape, are wound with a stator coil, and are disposed at a uniform angle except for a non-equiangular pitch region, a circular outer peripheral yoke formed so as to be continuous with the outer peripheral side of the salient pole portions, a cut-out which is formed by cutting out part of the outer peripheral yoke in an approximate sector-shape except in the non-equiangular pitch region of the salient pole portions, and a compensating pole plate which is provided in the cut-out along the ends on the inner peripheral side of the non-equiangular pitch region where the salient pole portions are formed.

Abstract: 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.

Abstract: 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.

Abstract: With a hydrodynamic bearing device 10, a first gap G1 is formed between a shaft 12 and a sleeve 11. A second gap G2 is formed between a sleeve cap 16 and the sleeve 11, and holds a lubricant 17. A thrust bearing member 21 is disposed near the inner peripheral surface of a center hole 16a of the sleeve cap 16. A third gap G3 is formed between the thrust bearing member 21 and the sleeve cap 16, and is open to the atmosphere. A fourth gap G4 is formed between the thrust bearing member 21 and the sleeve 11. The lubricant 17 circulates along a circulation passage that includes a communicating path 11b, the first gap G1 and the second gap G2.

Abstract: A set of radial dynamic pressure generating grooves constitute a radial bearing, and an entire width (L) of the radial dynamic pressure generating groove is reduced. A set of thrust dynamic pressure generating grooves constituting a thrust bearing are formed so that an area where a maximal thrust dynamic pressure is generated (diameter) is increased, and a bearing angle stiffness of the thrust bearing is increased. The thrust bearing having the high bearing angle stiffness shares a moment load applied to a shaft to thereby compensate for a bearing angle stiffness of the radial bearing whose bearing stiffness is small because an entire width of the radial bearing is small. Thus, a thin-shaped hydrodynamic bearing capable of withstanding a large moment load is obtained.

Abstract: With a spindle motor 20, a stator core 8 comprises a plurality of salient pole portions 51 that are formed in a radial shape, are wound with a stator coil 9, and are disposed at a uniform angle except for a non-equiangular pitch region, an circular outer peripheral yoke 52 formed so as to be continuous with the outer peripheral side of the salient pole portions 51, a cut-out 55 which is formed by cutting out part of the outer peripheral yoke 52 in an approximate sector-shape except in the non-equiangular pitch region of the salient pole portions 51, and a compensating pole plate 11 which is provided in the cut-out 55 along the ends on the inner peripheral side of the non-equiangular pitch region where the salient pole portions 51 are formed.

Abstract: 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.

Abstract: With a spindle motor 20, a stator core 8 comprises a plurality of salient pole components 51 that are formed in a radial shape, are wound with a stator coil 9, and are disposed at a uniform angle except for a non-equiangular pitch portion, an circular outer peripheral yoke 52 formed so as to be continuous with the outer peripheral side of the salient pole components 51, a cut-out 55 which is formed by cutting out part of the outer peripheral yoke 52 in an approximate sector-shape except in the non-equiangular pitch portion of the salient pole components 51, and a compensating pole plate 11 which is provided in the cut-out 55 along the ends on the inner peripheral side of the non-equiangular pitch portion where the salient pole components 51 are formed.

Abstract: 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.

Abstract: A hydrodynamic bearing device with high reliability, with which reductions in size, weight, and thickness can be achieved, as well as a motor and a disk driving apparatus that make use of this hydrodynamic bearing device. The hydrodynamic bearing device comprises a shaft, a thrust flange, a sleeve, a seal plate, and a retaining plate. A radial dynamic pressure bearing is formed in the radial direction gap between the shaft and the sleeve, and a thrust dynamic pressure bearing is formed in the thrust dynamic bearing gap between the sleeve and the thrust flange. A communicating hole is formed for communicating between the gap between the sleeve and the seal plate and the thrust direction gap between the sleeve and the thrust flange. The radial dynamic pressure bearing and/or the thrust dynamic pressure bearing are formed such that a lubricating oil circulates in the gap between the sleeve and the seal plate from the inner peripheral side of the sleeve toward the outer peripheral side.

Abstract: 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.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

Abstract: In order to prevent oil leakage in a hydrodynamic bearing device comprising an opening section in close proximity to a radial bearing and a lubricating fluid reservoir, a shaft 10, thrust flange 16, sleeve 11, seal plate 21, and stopper plate 20 are provided, a radial dynamic pressure bearing is formed in a radial clearance between the shaft 10 and sleeve 11, and a thrust dynamic pressure bearing is formed in a thrust direction clearance between the sleeve 11 and thrust flange 16. A connecting hole 11d is formed that connects a gap between the sleeve 11 and seal plate 21 and a thrust direction gap between the sleeve 11 and thrust flange 16. The relationship A<B<C is satisfied, where A is a radial clearance, B is a clearance between an outer peripheral surface of the shaft 10 and an inner peripheral surface of the seal plate 21, and C is a clearance between a lower surface of the seal plate 21 and an upper end face of the sleeve 11.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.

Abstract: With a spindle motor 20, a stator core 8 comprises a plurality of salient pole components 51 that are formed in a radial shape, are wound with a stator coil 9, and are disposed at a uniform angle except for a non-equiangular pitch portion, an circular outer peripheral yoke 52 formed so as to be continuous with the outer peripheral side of the salient pole components 51, a cut-out 55 which is formed by cutting out part of the outer peripheral yoke 52 in an approximate sector-shape except in the non-equiangular pitch portion of the salient pole components 51, and a compensating pole plate 11 which is provided in the cut-out 55 along the ends on the inner peripheral side of the non-equiangular pitch portion where the salient pole components 51 are formed.

Abstract: To provide a hydrodynamic bearing device with high reliability, with which reductions in size, weight, and thickness can be achieved, as well as a motor and a disk driving apparatus that make use of this hydrodynamic bearing device. The hydrodynamic bearing device pertaining to the present invention comprises a shaft 10, a thrust flange 16, a sleeve 11, a seal plate 21, and a retaining plate 20. A radial dynamic pressure bearing is formed in the radial direction gap between the shaft 10 and the sleeve 11, and a thrust dynamic pressure bearing is formed in the thrust dynamic bearing gap between the sleeve 11 and the thrust flange 16. A communicating hole 11d is formed for communicating between the gap between the sleeve 11 and the seal plate 21 and the thrust direction gap between the sleeve 11 and the thrust flange 116.

Abstract: In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substantially parallel to each other. The salient pole arm portions locate approximately halfway between a lower surface of a hub and an upper surface of a base. Further, a thickness of a magnetic plate is set to be 0.5 to 0.9 times that of other portions.