JP2007309528A - Hydrodynamic pressure bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the effect of a capillary seal of a hydrodynamic pressure bearing. <P>SOLUTION: The hydrodynamic pressure bearing comprising a flanged shaft 1 having a shaft 2 and a flange 3, a sleeve 4 and an annular cover member 5, is constituted to fill a lubricating fluid F in a single bag type fluid filling part formed between these bearing components and having a ring-like opening between the outer peripheral surface of the shaft 1 and the inner peripheral surface of a through hole of the annular cover member 5. The outside diameter of the through hole of the annular cover member 5 is made smaller than the inside diameter to form a tapered face, and the outside diameter of the upper side shaft 2 located in the through hole of the annular cover member 5 is made smaller than the inside diameter to form a tapered face. Further, the inclination angle of the former is made larger than the inclination angle of the latter. A ring-like opening functioning as the capillary seal is thereby formed as an inverted funnel shaped ring-like opening with the outside diameter smaller than the inside diameter, and the lubricating fluid F is strongly led into the bearing by the force of a capillary tube in a stationary time and by centrifugal force in addition to the force of the capillary tube in a rotating time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention comprises a bearing component including a shaft and a sleeve that receives the shaft, and a single bag-like fluid that communicates a plurality of clearances including a radial clearance and a thrust clearance formed between these bearing components. The present invention relates to a capillary seal structure of a fluid dynamic pressure bearing in which a filling fluid is filled, a radial dynamic pressure generating groove is provided in the radial gap, and a thrust dynamic pressure generating groove is provided in the thrust gap.

  For example, as shown in FIG. 6, the fluid dynamic pressure bearing has a flanged shaft 1, a sleeve 4, and an annular lid member 5 as bearing components. A plurality of minute gaps R1, R2, R3, R4, and R5 formed between these bearing constituent members communicate with each other to form a single bag-like fluid filling portion. F is filled. The flanged shaft 1 is a substantially cross-shaped shaft formed of a cylindrical portion 2 that becomes a shaft and a ring portion 3 that becomes a flange.

  The flanged shaft 1 is manufactured by cutting the cylindrical portion 2 and the ring portion 3 or by combining the cylindrical portion 2 and the ring portion 3 which are separate parts. The coupling is performed by pressing the cylindrical portion 2 into the through hole of the ring portion 3. The sleeve 4 has an inner peripheral surface that receives the flanged shaft 1 that is a substantially cross-shaped shaft. That is, the sleeve 4 has a small-diameter cylindrical portion into which the lower column portion 2 of the flanged shaft 1 is rotatably inserted and a large-diameter cylindrical portion into which the ring portion 3 of the flanged shaft 1 is rotatably inserted. Stepped sleeve.

  Among the minute gaps R1, R2, R3, R4, and R5, the minute gap R4 is a radial gap. The minute gap R4, which is a radial gap, is a minute gap formed by the outer peripheral surface of the lower cylindrical portion 2 and the inner peripheral surface of the small diameter cylindrical portion of the sleeve 4. A radial dynamic pressure generating groove G1 such as a herringbone groove is formed on the outer peripheral surface of the lower cylindrical portion 2.

  Among the minute gaps R1, R2, R3, R4, and R5, the minute gaps R1 and R3 are thrust gaps. The minute gap R <b> 1 that is the first thrust gap is a minute gap formed by the outer radial surface of the ring portion 3 and the facing surface of the annular lid member 5. The minute gap R3, which is the second thrust gap, is formed by a radial surface inside the ring portion 3 and a radial boundary surface between the small diameter cylindrical portion and the large diameter cylindrical portion of the sleeve 4. Spiral thrust dynamic pressure generating grooves G2 (see FIG. 7) such as herringbone grooves are formed on the outer and inner radial surfaces of the ring portion 3, that is, the upper surface and the lower surface, respectively.

  The tapered minute gap S formed between the outer peripheral surface of the upper cylindrical portion 2 and the inner peripheral surface of the through hole of the annular lid member 5 leaks the lubricating oil F to the outside using capillary force and surface tension. It is a capillary seal part that functions so as not to occur.

  By the way, the taper-shaped minute gap S is a ring-shaped opening to the atmosphere of a one-bag-shaped fluid filling part formed by communicating a plurality of minute gaps R1, R2, R3, R4, and R5. In order to prevent the lubricating fluid filled in the single bag-like fluid filling portion from leaking to the outside, a funnel-shaped ring-shaped opening having an outer diameter larger than the inner diameter is formed. More specifically, the tapered minute gap S is formed between a tapered surface having an outer diameter larger than the inner diameter of the inner peripheral surface of the through hole of the annular lid member 5 and the outer peripheral surface of the upper cylindrical portion 2. A funnel-shaped ring-shaped opening formed therebetween.

  As described above, the conventional capillary seal portion utilizes capillary force and surface tension, and has an advantage that it is easy to manufacture because of its simple shape, and is widely used in various fluid dynamic pressure bearings. However, the conventional fluid dynamic pressure bearing provided with the capillary seal portion utilizing the capillary force and the surface tension as described above is a so-called oil leak in which the lubricating fluid leaks out of the bearing when used in a severe environment. Serious problems can occur. Oil leakage causes bearing seizure and is highly likely to cause a fatal problem for the motor such as motor stoppage.

  By the way, among the minute gaps R1, R2, R3, R4, and R5, the minute gaps R2 and R5 are lubricating oil reservoirs that act so as not to run out of oil in the thrust gaps R1 and R3 and the radial gap R4 during high-speed rotation. is there. In a fluid dynamic bearing having such a lubricating oil reservoir, if foreign matter such as dust or wear powder is present in the lubricating oil reservoir, there is a risk that bubbles will be generated in the lubricating oil. . When such bubbles are generated, there are problems such as the smooth circulation of the lubricating oil being impaired and the dynamic pressure being lowered, or the lubricating oil leaking to the outside from the tapered minute gap S. Therefore, in the hydrodynamic bearing device disclosed in Japanese Patent Laid-Open No. 10-339320, the lubricating oil does not leak even if bubbles are generated in the gap inner volume of the capillary seal portion corresponding to the tapered minute gap S. It is sized. In addition, an air pocket is provided in the lubricating oil reservoir, and the shape and angle of the lubricating oil reservoir are devised. However, such a means cannot be employed for a thin dynamic pressure bearing.

  The first problem to be solved is to improve the sealing effect of the capillary seal portion of the fluid dynamic pressure bearing.

  The second problem to be solved is to improve the sealing effect of the capillary seal portion of the fluid dynamic pressure bearing provided with a lubricating oil reservoir that may generate bubbles.

  A third problem to be solved is a fluid filling portion formed between a shaft with a flange, a sleeve, and an annular lid member, and formed between these bearing constituent members, the outer peripheral surface of the shaft and the annular lid member. A fluid dynamic pressure bearing formed by filling a fluid filling portion having a ring-shaped opening functioning as a capillary seal portion between the inner peripheral surface and a lubricating fluid, or a fluid dynamic pressure bearing provided with the fluid dynamic pressure bearing In the motor, the sealing effect of the ring-shaped opening is enhanced.

  A fourth problem to be solved is a fluid filling portion formed between a shaft with a flange, a sleeve, and a disc-like lid member, and formed between these bearing constituent members. A fluid dynamic pressure bearing configured by filling a fluid filling portion having a ring-shaped opening functioning as a capillary seal portion between a peripheral surface and a lubricating fluid, or a fluid dynamic pressure bearing motor including the fluid dynamic pressure bearing And improving the sealing effect of the ring-shaped opening.

  The invention according to claim 1 that solves the above-mentioned problem comprises a shaft and a bearing component that includes a sleeve that receives the shaft, and a plurality of radial gaps and thrust gaps that are formed between the bearing components. In a fluid dynamic pressure bearing in which a fluid filling portion communicating with a gap is filled with a lubricating fluid, a radial dynamic pressure generating groove is provided in the radial gap, and a thrust dynamic pressure generating groove is provided in the thrust gap. In the inner diameter of the ring-shaped opening of the fluid filling part that functions as a capillary seal part, a reverse funnel-shaped ring-shaped opening having an outer diameter smaller than an inner diameter is used.

  According to a second aspect of the present invention for solving the first and second problems, a shaft with a flange having a shaft and a flange, an inner periphery that forms a radial gap between one opening and the outer peripheral surface of the flange. A fluid filling in which a sleeve having a surface and an annular lid member that closes the opening of the sleeve are used as bearing components, and a plurality of minute gaps including radial gaps and thrust gaps formed between these bearing components are communicated A fluid dynamic pressure bearing configured to fill a lubricating fluid in a portion, provide a radial dynamic pressure generating groove in the radial gap, and provide a thrust dynamic pressure generating groove in the thrust gap, and function as a capillary seal portion. The inner diameter of the ring-shaped opening of the fluid filling portion is a reverse funnel-shaped ring-shaped opening in which the outer diameter is smaller than the inner diameter.

The reverse funnel-shaped ring-shaped opening has a tapered surface in which the outer diameter of the through hole of the annular lid member is smaller than the inner diameter, and the outer side of the shaft located in the through hole of the annular lid member The tapered surface has a diameter smaller than the inner diameter, and the former inclination angle is larger than the latter inclination angle.
The reverse funnel-shaped ring-shaped opening has a tapered surface in which the outer diameter of the through hole of the annular lid member is smaller than the inner diameter, and projects so as to be positioned in the through hole of the annular lid member. It was assumed that the outer diameter of the annular projecting portion of the flange was a tapered surface smaller than the inner diameter, and the former inclination angle was made larger than the latter inclination angle.

  Further, the invention of claim 5 for solving the first and third problems includes a flanged shaft having a shaft and a flange, a large-diameter opening and a small-diameter opening, and an outer peripheral surface of the shaft. And a disk-shaped lid member that closes the large-diameter opening of the sleeve as a bearing constituent member, and the radial gap formed between these bearing constituent members. And a fluid filling portion communicating with a plurality of minute gaps including a thrust gap is filled with a lubricating fluid, a radial dynamic pressure generating groove is provided in the radial gap, and a thrust dynamic pressure generating groove is provided in the thrust gap. In the fluid dynamic pressure bearing, a ring-shaped opening that functions as a capillary seal portion of the fluid filling portion is formed between the small-diameter opening of the sleeve and the shaft that passes through the opening. In the inner diameter of the ring-shaped openings, in which an inverted funnel-shaped ring-shaped opening in which the outer diameter smaller than the inner diameter.

  According to the present invention, the lubricating fluid is drawn from the ring-shaped opening functioning as a capillary seal by pulling the lubricating fluid into the bearing by capillary force when stationary and by centrifugal force in addition to capillary force when rotating. A very high sealing effect that prevents leakage is obtained. Moreover, this high sealing effect during rotation is maintained even if bubbles are generated in the lubricating oil.

  In particular, a ring-shaped fluid dynamic structure comprising a flanged shaft having a ring having a radial dynamic pressure generating groove formed on the outer peripheral surface thereof and a thrust dynamic pressure generating groove formed on a radial surface thereof, and a sleeve receiving the ring. Since the pressure bearing has a large volume of the single bag-like fluid filling portion, the sealing effect of the ring-type fluid dynamic pressure bearing to which the present invention using the centrifugal force is applied is extremely large.

  Moreover, although it is a fluid dynamic pressure bearing capable of obtaining such a very high sealing effect, it can be manufactured without increasing the number of parts and the number of manufacturing steps, so that even if the improvement according to the present invention is applied, the cost of the product is not increased. There is also an advantage.

  As shown in FIG. 1, the fluid dynamic pressure bearing according to the first embodiment of the present invention comprises a flanged shaft 1, a sleeve 4, and an annular lid member 5 as bearing components. A plurality of minute gaps R1, R2, R3, R4, and R5 formed between these bearing constituent members communicate with each other to form a single bag-like fluid filling portion. F is filled. The flanged shaft 1 is a substantially cross-shaped shaft formed of a cylindrical portion 2 that becomes a shaft and a ring portion 3 that becomes a flange. In the fluid dynamic pressure bearing according to the first embodiment, the ring portion 3 functions as a thrust bearing constituent member.

  The flanged shaft 1 is manufactured by cutting the cylindrical portion 2 and the ring portion 3 or by combining the cylindrical portion 2 and the ring portion 3 which are separate parts. The coupling is performed by pressing the cylindrical portion 2 into the through hole of the ring portion 3. The sleeve 4 has an inner peripheral surface that receives the flanged shaft 1 that is a substantially cross-shaped shaft. That is, the sleeve 4 has a small-diameter cylindrical portion into which the lower column portion 2 of the flanged shaft 1 is rotatably inserted and a large-diameter cylindrical portion into which the ring portion 3 of the flanged shaft 1 is rotatably inserted. Stepped sleeve.

  Among the minute gaps R1, R2, R3, R4, and R5, the minute gap R4 is a radial gap. The minute gap R4, which is a radial gap, is a minute gap formed by the outer peripheral surface of the lower cylindrical portion 2 and the inner peripheral surface of the small diameter cylindrical portion of the sleeve 4. A radial dynamic pressure generating groove G1 such as a herringbone groove is formed on the outer peripheral surface of the lower cylindrical portion 2.

  Among the minute gaps R1, R2, R3, R4, and R5, the minute gaps R1 and R3 are thrust gaps. The minute gap R <b> 1 that is the first thrust gap is a minute gap formed by the outer radial surface of the ring portion 3 and the facing surface of the annular lid member 5. The minute gap R3, which is the second thrust gap, is formed by a radial surface inside the ring portion 3 and a radial boundary surface between the small diameter cylindrical portion and the large diameter cylindrical portion of the sleeve 4. Spiral thrust dynamic pressure generating grooves G2 (see FIG. 7) such as herringbone grooves are formed on the outer and inner radial surfaces of the ring portion 3, that is, the upper surface and the lower surface, respectively.

  The tapered minute gap S formed between the tapered outer peripheral surface 2a of the upper cylindrical portion 2 and the tapered inner peripheral surface 5a of the through hole of the annular lid member 5 is centrifugally separated in addition to the capillary force and the surface tension. It is a capillary seal part of the structure which characterizes the present invention which functions so that lubricating oil F does not leak outside using force.

  That is, the tapered minute gap S that characterizes the present invention is a reverse funnel-shaped ring-shaped opening unlike the conventional one. More specifically, the reverse funnel-shaped ring-shaped opening has a tapered surface in which the outer diameter of the through hole of the annular lid member 5 is smaller than the inner diameter, and the upper funnel located in the through hole of the annular lid member 5. The outer diameter of the shaft 2 is a tapered surface smaller than the inner diameter, and the former inclination angle is made larger than the latter inclination angle.

  With such a reverse funnel-shaped ring-shaped opening, as shown in FIG. 2B, the lubricating fluid receives a centrifugal force indicated by the right arrow in addition to the capillary force indicated by the left arrow during rotation. Therefore, the lubricating fluid is drawn into the bearing with a strong force. Therefore, the fluid dynamic pressure bearing provided with the capillary seal portion of the reverse funnel-shaped ring opening according to the present invention greatly reduces the possibility that the lubricating fluid leaks to the outside during rotation, and the sealing effect is enhanced. Moreover, the sealing effect during rotation is maintained even if bubbles are generated in the lubricating oil. When stationary, as shown in FIG. 2A, the sealing effect is the same as the conventional one. That is, the lubricating fluid is held in the bearing by the capillary force and surface tension indicated by the left arrow.

  As shown in FIG. 3, the fluid dynamic pressure bearing according to the second embodiment of the present invention has a flanged shaft 1, a sleeve 4, and an annular lid member 5 as bearing components. A plurality of minute gaps R1, R2, R3, R4, and R5 formed between these bearing constituent members communicate with each other to form a single bag-like fluid filling portion. F is filled. The flanged shaft 1 is a substantially inverted T-shaped shaft formed of a cylindrical portion 2 that becomes a shaft and a ring portion 3 that becomes a flange. In the fluid dynamic pressure bearing according to the second embodiment, the ring portion 3 functions as a constituent member of the radial bearing together with the thrust bearing constituent member. And the ring part 3 in FIG. 3 is formed with an annular protrusion having a tapered outer peripheral surface 3a.

  The flanged shaft 1 is manufactured by joining a cylindrical part 2 and a ring part 3 which are separate parts. The coupling is performed by pressing the cylindrical portion 2 into the through hole of the ring portion 3. The sleeve 4 has an inner peripheral surface that receives the flanged shaft 1 that is a substantially inverted T-shaped shaft. That is, the sleeve 4 is a sleeve having a substantially rectangular cross section having a cylindrical portion into which the ring portion 3 of the flanged shaft 1 is rotatably inserted.

  Among the minute gaps R1, R2, R3, R4, and R5, the minute gap R2 is a radial gap. A minute gap R <b> 2 that is a radial gap is a minute gap formed between the outer peripheral surface of the ring portion 3 and the inner peripheral surface of the sleeve 4. A radial dynamic pressure generating groove G1 such as a herringbone groove is formed on the outer peripheral surface of the ring portion 3.

  Among the minute gaps R1, R2, R3, R4, and R5, the minute gaps R1 and R3 are thrust gaps. The minute gap R <b> 1 that is the first thrust gap is a minute gap formed by the outer radial surface of the ring portion 3 and the facing surface of the annular lid member 5. Further, the minute gap R <b> 3 that is the second thrust gap is formed by the radial surface inside the ring portion 3 and the bottom surface of the sleeve 4. In FIG. 3, the central portion of the bottom surface of the sleeve 4 is formed by a disc-like lid member 4 b, but this may be formed integrally with the sleeve 4. Spiral thrust dynamic pressure generating grooves G2 (see FIG. 7) such as herringbone grooves are formed on the outer and inner radial surfaces of the ring portion 3, that is, the upper surface and the lower surface, respectively.

  The tapered minute gap S formed between the tapered inner peripheral surface 5a of the through hole of the annular lid member 5 and the tapered outer peripheral surface 3a of the annular protrusion of the ring portion 3 is in addition to capillary force and surface tension. This is a capillary seal part having a structure characterizing the present invention that functions to prevent the lubricating oil F from leaking to the outside by utilizing centrifugal force.

  That is, the tapered minute gap S that characterizes the present invention is a reverse funnel-shaped ring-shaped opening unlike the conventional one. More specifically, the reverse funnel-shaped ring-shaped opening has a tapered surface 5a in which the outer diameter of the through hole of the annular lid member 5 is smaller than the inner diameter, and the outer diameter of the annular protrusion of the ring portion 3 is the inner diameter. The tapered surface 3a is made smaller and the former inclination angle is made larger than the latter inclination angle.

  With such a reverse funnel-shaped ring-shaped opening, as shown in FIG. 2B, the lubricating fluid receives a centrifugal force indicated by the right arrow in addition to the capillary force indicated by the left arrow during rotation. Therefore, the lubricating fluid is drawn into the bearing with a strong force. Therefore, the fluid dynamic pressure bearing provided with the capillary seal portion of the reverse funnel-shaped ring opening according to the present invention greatly reduces the possibility that the lubricating fluid leaks to the outside during rotation, and the sealing effect is enhanced. Moreover, this high sealing effect during rotation is maintained even if bubbles are generated in the lubricating oil. When stationary, as shown in FIG. 2A, the sealing effect is the same as the conventional one. That is, the lubricating fluid is held in the bearing by the capillary force and surface tension indicated by the left arrow.

  The fluid dynamic pressure bearing according to the third embodiment of the present invention has a flanged shaft 1 and a sleeve 4 as bearing components as shown in FIG. A plurality of minute gaps R1, R2, R3, and R4 formed between these bearing constituent members communicate with each other to form a single bag-like fluid filling portion, and lubricating oil F is supplied to the single bag-like fluid filling portion. Filled. The flanged shaft 1 is a substantially inverted T-shaped shaft formed of a cylindrical portion 2 that becomes a shaft and a ring portion 3 that becomes a flange. In the fluid dynamic pressure bearing of the third embodiment, the ring portion 3 functions as a thrust bearing constituent member. Moreover, the taper part which has the outer peripheral surface 2a with a taper is formed in the upper part of the cylindrical part 2 of the shaft 1 with a flange. Further, the opening of the sleeve 4 is formed to have a tapered inner peripheral surface 4a.

  The flanged shaft 1 is manufactured by joining a cylindrical part 2 and a ring part 3 which are separate parts. The coupling is performed by pressing the cylindrical portion 2 into the through hole of the ring portion 3. The sleeve 4 has an inner peripheral surface that receives the flanged shaft 1 that is a substantially inverted T-shaped shaft. That is, the sleeve 4 is a stepped sleeve having a large-diameter cylindrical portion into which the ring portion 3 of the flanged shaft 1 is rotatably inserted and a small-diameter cylindrical portion into which the column portion 2 is rotatably inserted.

  Among the minute gaps R1, R2, R3, and R4, the minute gap R4 is a radial gap. The minute gap R4, which is a radial gap, is a minute gap formed between the outer peripheral surface of the cylindrical portion 2 and the inner peripheral surface of the small diameter cylindrical portion of the sleeve 4. A radial dynamic pressure generating groove G1 such as a herringbone groove is formed on the outer peripheral surface of the cylindrical portion 2.

  Among the minute gaps R1, R2, R3, and R4, the minute gaps R1 and R3 are thrust gaps. The minute gap R1 which is the first thrust gap is a minute gap formed by the lower radial surface of the ring portion 3 and the bottom surface of the large diameter cylindrical portion of the sleeve 4. The minute gap R3, which is the second thrust gap, is formed by the radial surface on the upper side of the ring portion 3 and the radial boundary surface between the small diameter cylindrical portion and the large diameter cylindrical portion of the sleeve 4. In FIG. 4, the bottom surface of the large-diameter cylindrical portion of the sleeve 4 is formed by a disc-like lid member 4b. Spiral thrust dynamic pressure generating grooves G2 (see FIG. 7) such as herringbone grooves are formed on the outer and inner radial surfaces of the ring portion 3, that is, the upper surface and the lower surface, respectively.

  The taper minute gap S formed between the tapered outer peripheral surface 2a of the cylindrical portion 2 of the flanged shaft 1 and the tapered inner peripheral surface 4a of the opening of the sleeve 4 is centrifugal in addition to capillary force and surface tension. It is a capillary seal part of the structure which characterizes the present invention which functions so that lubricating oil F does not leak outside using force.

  That is, the tapered minute gap S that characterizes the present invention is a reverse funnel-shaped ring-shaped opening unlike the conventional one. More specifically, the reverse funnel-shaped ring-shaped opening has a tapered surface 4a in which the outer diameter of the opening of the sleeve 4 is smaller than the inner diameter, and the outer diameter of the tapered part of the cylindrical portion 2 is smaller than the inner diameter. The tapered surface 2a is formed and the former inclination angle is made larger than the latter inclination angle.

  With such a reverse funnel-shaped ring-shaped opening, as shown in FIG. 2B, the lubricating fluid receives a centrifugal force indicated by the right arrow in addition to the capillary force indicated by the left arrow during rotation. Therefore, the lubricating fluid is drawn into the bearing with a strong force. Therefore, the fluid dynamic pressure bearing provided with the capillary seal portion of the reverse funnel-shaped ring opening according to the present invention greatly reduces the possibility that the lubricating fluid leaks to the outside during rotation, and the sealing effect is enhanced. Moreover, this high sealing effect during rotation is maintained even if bubbles are generated in the lubricating oil. When stationary, as shown in FIG. 2A, the sealing effect is the same as the conventional one. That is, the lubricating fluid is held in the bearing by the capillary force and surface tension indicated by the left arrow.

  5 shows a fluid dynamic pressure bearing according to the first embodiment of FIG. 1, in which a rotor including a cup-shaped hub 6 on which a magnetic disk is loaded and a rotor magnet 8 attached to the inner peripheral surface of the skirt portion of the cup-shaped hub. 1 is a cross-sectional view of an embodiment of a fluid dynamic bearing motor that is rotatably supported by a stator. The stator includes a base substrate 9, a fluid dynamic pressure bearing sleeve 4 fixed to the base substrate 9, and a stator coil 7 attached to the outer peripheral surface of the sleeve 4. The cup-shaped hub 6 of the rotor is fixed coaxially to the flanged shaft 1 of the fluid dynamic pressure bearing. The fluid dynamic bearing motor shown in FIG. 5 rotates due to the mutual electromagnetic action between the stator coil 7 and the rotor magnet 8.

  The fluid dynamic pressure bearing according to the present invention has been described in detail with respect to the first to third embodiments. By the way, all of these first to third embodiments are shaft rotation type fluid dynamic pressure bearings. However, the present invention is naturally applied to a shaft fixed type fluid dynamic pressure bearing, and an expected sealing effect. It plays.

It is sectional drawing of the fluid dynamic pressure bearing of 1st Embodiment of this invention which exaggerated and showed the micro clearance gap. It is a partial expanded sectional view of the fluid dynamic pressure bearing of a 1st embodiment of the present invention. It is sectional drawing of the fluid dynamic pressure bearing of 2nd Embodiment of this invention which exaggerated and showed the micro clearance gap. It is sectional drawing of the fluid dynamic pressure bearing of 3rd Embodiment of this invention which exaggerated and showed the micro clearance gap. It is sectional drawing of one Example of the fluid bearing motor provided with the fluid dynamic pressure bearing of 1st Embodiment of this invention. It is sectional drawing of the fluid dynamic pressure bearing of one conventional example which exaggerated and showed the micro clearance gap. It is the figure which showed an example of the thrust dynamic pressure generation groove | channel G2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2 Cylindrical part or shaft 2a Tapered outer peripheral surface 3 Ring part or flange 3a Tapered outer peripheral surface of annular projecting portion of flange 4 Sleeve 4a Tapered inner peripheral surface 4b Disk-shaped lid member 5 Annular lid member 5a Tapered inner periphery Surface 6 Hub 7 Stator coil 8 Rotor magnet 9 Base substrate F Lubricating oil or lubricating fluid R1 to R5 Minute gap G1 Radial dynamic pressure generating groove G2 Thrust dynamic pressure generating groove

Claims (6)

A lubricating fluid is provided in a fluid filling portion that includes a shaft and a bearing component that includes a sleeve that receives the shaft, and that communicates a plurality of gaps including a radial gap and a thrust gap formed between the bearing components. In the fluid dynamic pressure bearing in which a radial dynamic pressure generating groove is provided in the radial gap, and a thrust dynamic pressure generating groove is provided in the thrust gap, the fluid filling portion functioning as a capillary seal portion is provided. A fluid dynamic pressure bearing characterized in that the inner diameter of the ring-shaped opening is a reverse funnel-shaped ring-shaped opening whose outer diameter is smaller than the inner diameter. A bearing structure comprising a flanged shaft having a shaft and a flange, an inner peripheral surface forming a radial gap between the outer peripheral surface of the shaft and a sleeve having an opening, and an annular lid member closing the opening of the sleeve As a member, a lubricating fluid is filled in a fluid filling portion communicating with a plurality of minute gaps including a radial gap and a thrust gap formed between these bearing constituent members, and a radial dynamic pressure generating groove is provided in the radial gap. In the fluid dynamic pressure bearing formed by providing a thrust dynamic pressure generating groove in the thrust gap, the outer diameter of the inner diameter of the ring-shaped opening of the fluid filling portion functioning as a capillary seal portion is smaller than the inner diameter. A fluid dynamic pressure bearing characterized by having a reverse funnel-shaped ring opening. The reverse funnel-shaped ring-shaped opening has a tapered surface in which the outer diameter of the through hole of the annular lid member is smaller than the inner diameter, and the outer diameter of the shaft located in the through hole of the annular lid member. 3. The fluid dynamic pressure bearing according to claim 2, wherein the fluid dynamic pressure bearing has a tapered surface smaller than the inner diameter, and the former inclination angle is larger than the latter inclination angle. The reverse funnel-shaped ring-shaped opening has a tapered surface in which the outer diameter of the through hole of the annular lid member is smaller than the inner diameter, and the flange that protrudes so as to be positioned in the through hole of the annular lid member. 3. The fluid dynamic pressure bearing according to claim 2, wherein the outer diameter of the annular protrusion is a tapered surface smaller than the inner diameter, and the former inclination angle is larger than the latter inclination angle. . A sleeve having a shaft with a flange having a shaft and a flange, an inner peripheral surface having a large-diameter opening and a small-diameter opening and forming a radial gap between the outer peripheral surface of the shaft, and the sleeve A disk-shaped lid member that closes the large-diameter opening is used as a bearing component, and a lubricating fluid is supplied to a fluid filling portion that communicates a plurality of minute gaps including radial gaps and thrust gaps formed between these bearing components. In the fluid dynamic pressure bearing constructed by providing a radial dynamic pressure generating groove in the radial gap and providing a thrust dynamic pressure generating groove in the thrust gap, the ring shape of the fluid filling portion functioning as a capillary seal portion The inner diameter of the ring-shaped opening formed between the small-diameter opening of the sleeve and the shaft that passes through the opening. Remote fluid dynamic bearing, characterized in that the smaller the reverse funnel-shaped ring-shaped opening. A fluid dynamic bearing motor using the fluid dynamic pressure bearing according to claim 1.

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