JP4937619B2 - Hydrodynamic bearing device - Google Patents

Description

  The present invention relates to a hydrodynamic bearing device.

  The dynamic pressure bearing device is a bearing device that rotatably supports a rotating member to be supported by a dynamic pressure action of a lubricating fluid generated in a bearing gap. This hydrodynamic bearing device has characteristics such as high-speed rotation, high rotation accuracy, and low noise. In recent years, utilizing these characteristics, information devices such as magnetic disk devices such as HDD and FDD, CD-ROM, Used for spindle motors mounted on optical disk devices such as CD-R / RW and DVD-ROM / RAM, magneto-optical disk devices such as MD and MO, etc., and mounted on personal computers (PCs) to cool the heat source. Widely used as a bearing for fan motors and the like.

  By the way, in the above-mentioned motor for information equipment, as the amount of information processing increases, the recording medium is laminated and the rotation speed is increased. Accordingly, the hydrodynamic bearing device is required to further improve the bearing rigidity, particularly the moment rigidity.

  As a means for improving the moment rigidity of a hydrodynamic bearing device, a structure in which the bearing span of the radial bearing portion is enlarged is generally used. For example, the structure is separated at two locations on the inner peripheral side of a single bearing body (bearing sleeve). In addition to a bearing having a radial bearing gap (for example, see Patent Document 1), the bearing body is formed by two bearing sleeves arranged in the axial direction, and one radial bearing gap is provided on the inner peripheral side of each bearing sleeve. (For example, refer to Patent Document 2).

Further, as another means for improving moment rigidity, a structure in which the bearing span of the thrust bearing portion is enlarged can be adopted. As a hydrodynamic bearing device having this type of structure, the thrust bearing portion is provided at both ends of the bearing sleeve. Is known (see, for example, Patent Document 3).
JP 2003-65324 A JP-A-11-269475 JP 2005-321089 A

  However, in the configuration of Patent Document 1, the bearing sleeve becomes longer as the bearing span increases. When the bearing sleeve becomes long, it becomes difficult to ensure the processing accuracy of the bearing sleeve. In particular, when the bearing sleeve is made of a sintered metal, it is difficult to obtain a uniform density at the time of compacting, and there is a possibility that desired bearing performance cannot be exhibited. Therefore, there is a limit to further expanding the bearing span.

  On the other hand, in the configuration of Patent Document 2, the bearing span of the radial bearing portion can be relatively easily increased without causing the above-described problem. At this time, with the aim of further improving the moment rigidity, for example, as disclosed in Patent Document 3, a thrust bearing portion formed of a dynamic pressure bearing may be provided on both ends of the bearing body. When using a sintered metal bearing body (bearing sleeve), dynamic pressure generating means such as a dynamic pressure groove that generates fluid dynamic pressure in the thrust bearing gap is provided on the end face of the bearing sleeve in consideration of formability. In many cases, however, each dynamic pressure groove needs to have a different inclination direction in consideration of the rotation direction. Therefore, two types of bearing sleeves are required, but they are formed in substantially the same shape at a level that is difficult to distinguish visually, and therefore their assembly direction and position are likely to be mistaken. If these are mistaken, they will not function as a bearing device, so special consideration is required for assembly, which may increase the processing cost.

  An object of the present invention is to provide a hydrodynamic bearing device that improves the ease of assembly and thereby has excellent moment rigidity at a low cost.

In order to solve the above problems, a hydrodynamic bearing device according to the present invention includes a housing, a bearing body fixed to the inner periphery of the housing, and one end surface and the other end surface of the bearing body, and a rotating member to be supported. First and second thrust bearing gaps formed between each other, a first dynamic pressure groove region for generating fluid dynamic pressure in the first thrust bearing gap, and a fluid dynamic pressure in the second thrust bearing gap. A radial bearing gap formed by a second dynamic pressure groove region , a radial bearing surface provided on the inner peripheral surface of the bearing body, and the rotating member in a radial direction non-contact with the fluid dynamic pressure generated in the radial bearing gap A radial bearing portion for supporting the bearing body, the bearing body having two bearing sleeves arranged side by side in an axial direction, both of the two bearing sleeves on the inner peripheral surface of the radial bearing surface Have Rutotomoni has one end surface and other end surface of the first dynamic pressure groove region and the second dynamic pressure generating groove area, respectively, and the first dynamic pressure groove region of one bearing sleeve to the first thrust bearing gap The second dynamic pressure groove region of the other bearing sleeve is exposed to the second thrust bearing gap.

  As described above, in the present invention, since the bearing body has two bearing sleeves, the bearing span of the radial bearing portion can be increased to increase the moment rigidity, and the manufacture of the bearing sleeve is facilitated. can do. Each of the bearing sleeves has a first dynamic pressure groove region and a second dynamic pressure groove region on both end faces, and the first dynamic pressure groove region of one of the bearing sleeves is the first dynamic pressure groove region. The second dynamic pressure groove area of the other bearing sleeve faces the second thrust bearing gap, which means that two identical bearing sleeves are arranged in the axial direction. . Accordingly, each bearing sleeve can be assembled to the housing without considering the upper and lower arrangements, thereby providing a first thrust bearing gap on one end side of the bearing body and a second thrust bearing gap on the other end side. A hydrodynamic bearing device excellent in moment rigidity can be easily formed. Further, the unit cost of parts can be reduced by the amount that the bearing sleeves can be integrated into one type, and further, the management cost of parts can be reduced.

  If the first dynamic pressure groove region and the second dynamic pressure groove region are formed in different shapes, it is possible to easily identify the top and bottom of each bearing sleeve, and to further facilitate the assembly. The “different shape” here refers to, for example, a configuration in which one is formed by a plurality of dynamic pressure grooves arranged in a spiral shape and the other is formed by a plurality of dynamic pressure grooves arranged in a herringbone shape, and the same shape. The number of the arranged dynamic pressure grooves and the like are different from each other. From the viewpoint of enhancing the distinguishability, the former configuration is desirable. If the pressure required for the first thrust bearing gap and the second thrust bearing gap differs depending on the application of the hydrodynamic bearing device, the arrangement pattern of the hydrodynamic grooves may be changed accordingly. .

  A spacer member can be interposed between the two bearing sleeves. For example, when the bearing sleeve is formed of an oil-containing sintered metal, the spacer member can be formed of a material having no porous structure (non-porous material). In this case, since the amount of lubricating oil included in the bearing device can be reduced, the cost can be reduced by reducing the total amount of oil. Furthermore, as the amount of oil decreases, the volume of the seal space provided in the opening of the housing can be reduced, and the bearing span of the radial bearing portion can be further expanded.

  The hydrodynamic bearing device having the above-described configuration includes a motor having the hydrodynamic bearing device, a stator coil, and a rotor magnet, and among them, a motor that requires particularly high moment rigidity as the speed increases and the weight of the rotating body increases. Can be preferably used.

  As described above, according to the present invention, it is possible to facilitate the assembly of the bearing body to the housing, thereby providing a hydrodynamic bearing device having excellent moment rigidity at a low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 conceptually shows one configuration example of a spindle motor for information equipment incorporating a fluid dynamic bearing device 1 according to the present invention. This spindle motor is used in a disk drive device such as an HDD, and is opposed to the hydrodynamic bearing device 1 and the rotor (disk hub) 3 mounted on the shaft member 2 through a radial gap, for example. A stator coil 4 and a rotor magnet 5 are provided. The stator coil 4 is attached to the outer periphery of the bracket 6, and the rotor magnet 5 is attached to the inner periphery of the disk hub 3. The housing 7 of the hydrodynamic bearing device 1 is attached to the inner periphery of the bracket 6. The disk hub 3 holds one or more disks D such as magnetic disks. When the stator coil 4 is energized, the rotor magnet 5 is rotated by electromagnetic force between the stator coil 4 and the rotor magnet 5, whereby the disk hub 3 and the disk D held by the disk hub 3 are integrated with the shaft member 2. Rotate to.

  FIG. 2 shows an example of the hydrodynamic bearing device 1 used in the spindle motor. The hydrodynamic bearing device 1 includes a housing 7 on a fixed side, a bearing body 8 fixed to the inner periphery of the housing 7, a shaft member 2 constituting a rotating member, and two axial directions of the shaft member 2. The first and second flange portions 9 and 10 provided as main components are provided. In the present embodiment, the bearing body 8 includes two bearing sleeves 81 and 81 that are spaced apart from each other in the axial direction, and a spacer member 82 that is interposed between the bearing sleeves 81 and 81. For convenience of explanation, the description will be given with the side where the end of the shaft member 2 protrudes from the opening of the housing 7 as the upper side and the opposite side in the axial direction as the lower side.

  In the hydrodynamic bearing device 1 of the present embodiment, as will be described later, a first radial bearing portion R1 is provided between the inner peripheral surface 81a of the upper bearing sleeve 81 and the outer peripheral surface 2a of the shaft member 2, and the lower side A second radial bearing portion R <b> 2 is provided between the inner peripheral surface 81 a of the bearing sleeve 81 and the outer peripheral surface 2 a of the shaft member 2. Also, a first thrust bearing portion T1 is provided between the upper end surface 81b of the upper bearing sleeve 81 and the lower end surface 9b of the first flange portion 9, and the lower end surface 81c and the second end surface 81c of the lower bearing sleeve 81 are provided. A second thrust bearing portion T <b> 2 is provided between the upper end face 10 b of the flange portion 10.

  The shaft member 2 is formed of a metal material such as stainless steel. The shaft member 2 as a whole has a shaft shape having substantially the same diameter, and a relief portion 2b having a slightly smaller diameter than the other portions is formed in the middle portion thereof. In the outer peripheral surface 2a of the shaft member 2, a recessed portion, for example, a circumferential groove 2c is formed at a fixing position of the first and second flange portions 9 and 10. In this embodiment, the shaft member 2 is an integrally processed product of metal. However, the shaft member 2 may be a hybrid shaft made of metal and resin (the sheath is a metal and the core is a resin or the like).

  The housing 7 has a cylindrical shape with openings at both ends, and its inner peripheral surface 7a is formed in a straight cylindrical surface with a constant diameter in the axial direction. The housing 7 is, for example, a machined product of a metal material such as brass or aluminum, or an injection molded product of a resin composition. In the case of injection molding with a resin composition, usable base resins are not particularly limited. For example, polysulfone (PSF), polyethersulfone (PES), polyphenylsulfone (PPSF), polyetherimide (PEI) In addition to amorphous resins such as the above, crystalline resins such as liquid crystal polymer (LCP), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), and polyphenylene sulfide (PPS) can be used. The type of filler to be filled in the resin is not particularly limited. For example, as the filler, fibrous filler such as glass fiber, whisker-like filler such as potassium titanate, and scaly filler such as mica. A fibrous or powdery conductive filler such as carbon fiber, carbon black, graphite, carbon nanomaterial, or metal powder can be used. These fillers may be used alone or in combination of two or more.

  The two bearing sleeves 81, 81 constituting the bearing body 8 are both formed into a cylindrical shape with a porous body made of sintered metal, particularly a sintered body of sintered metal mainly composed of copper. Both bearing sleeves 81, 81 can also be formed of a soft metal such as brass. On the outer peripheral surface 81d of the bearing sleeve 81, axial grooves 81d1 are provided at a plurality of locations in the circumferential direction (three locations in the illustrated example) at equal intervals.

  The inner peripheral surface 81a of both bearing sleeves 81, 81 is provided with a region serving as the radial bearing surface A of each of the first and second radial bearing portions R1, R2, and the region serving as the radial bearing surface A includes, for example, As shown in FIG. 3A, a plurality of dynamic pressure grooves 81a1 arranged in a herringbone shape are formed symmetrically in the axial direction. The dynamic pressure grooves 81a1 can be arranged in other known shapes such as a spiral shape.

  For example, as shown in FIG. 3B, a first dynamic pressure groove comprising a plurality of dynamic pressure grooves 81b1 arranged in a spiral shape is formed in a part or all of the annular region of the upper end surface 81b of the bearing sleeves 81, 81. A region is formed. Further, as shown in FIG. 3C, for example, a second dynamic pressure groove region including a plurality of dynamic pressure grooves 81c1 arranged in a herringbone shape is formed in a part or all of the annular region of the lower end surface 81c. Has been. In the present embodiment, the first dynamic pressure groove region of the upper bearing sleeve 81 is the thrust bearing surface B of the first thrust bearing portion T1, and the second dynamic pressure groove region of the lower bearing sleeve 81 is the second. It becomes the thrust bearing surface C of the thrust bearing portion T2. The above-described dynamic pressure grooves 81 a 1, 81 b 1 and 81 c 1 can all be formed simultaneously with the molding of the bearing sleeve 81.

  A cylindrical spacer member 82 is interposed between the two bearing sleeves 81, 81. The spacer member 82 is formed of a metal material such as brass or aluminum or a resin material, and the inner peripheral surface 82 a is formed to have a larger diameter than the inner peripheral surface 81 a of the bearing sleeve 81. In the present embodiment, the spacer member 82 has its upper end surface 82b in contact with the lower end surface 81c of the upper bearing sleeve 81 and its lower end surface 82c in contact with the upper end surface 81b of the lower bearing sleeve 81. The housing 7 is disposed at a substantially central portion in the axial direction of the inner periphery. On the outer peripheral surface 82d of the spacer member 82, axial grooves 82d1 are provided at a plurality of locations (for example, three locations) in the circumferential direction.

  The first flange portion 9 and the second flange portion 10 are each formed in a ring shape from a soft metal material such as brass, other metal materials, or a resin material, and are bonded and fixed to the outer peripheral surface 2a of the shaft member 2, for example. At the time of bonding and fixing, the adhesive applied to the shaft member 2 is filled in the circumferential groove 2c as an adhesive reservoir and solidified, whereby the adhesive strength of the flange portions 9 and 10 to the shaft member 2 is improved.

  A first seal space S1 having a predetermined volume is formed between the outer peripheral surface 9a of the first flange portion 9 and the inner peripheral surface 7a on the upper end opening side of the housing 7, and the outer peripheral surface 10a of the second flange portion 10 is A second seal space S2 having a predetermined volume is formed between the housing 7 and the inner peripheral surface 7a on the lower end opening side. In this embodiment, the outer peripheral surface 9a of the 1st flange part 9 and the outer peripheral surface 10a of the 2nd flange part 10 are each formed in the taper surface shape gradually diameter-reduced toward the outer side of the bearing apparatus. Therefore, both the seal spaces S1 and S2 have a tapered shape that is gradually reduced in diameter in a direction approaching each other (inner direction of the housing 7). When the shaft member 2 rotates, the lubricating oil in both the seal spaces S1 and S2 is drawn in a direction in which the seal space becomes narrower (inner direction of the housing 7) due to the pulling action by capillary force and the pulling action by centrifugal force during rotation. It is drawn toward. Thereby, the leakage of the lubricating oil from the inside of the housing 7 is effectively prevented. In order to reliably prevent oil leakage, a film made of an oil repellent agent can be formed on each of the upper and lower end surfaces of the housing 7, the upper end surface 9c of the first flange portion 9, and the lower end surface 10c of the second flange portion 10 ( (Not shown).

  The first and second seal spaces S <b> 1 and S <b> 2 have a buffer function that absorbs a volume change amount associated with a temperature change of the lubricating oil filled in the internal space of the housing 7. The oil level is always in both the seal spaces S1 and S2 within the assumed temperature change range. In order to realize this, the sum of the volumes of the seal spaces S1, S2 is set to be larger than at least the volume change amount associated with the temperature change of the lubricating oil filled in the internal space.

  The assembly of the hydrodynamic bearing device 1 having the above configuration is performed as follows, for example.

  The bearing sleeves 81 and 81 and the spacer member 82 (bearing body 8) are fixed to the inner peripheral surface 7a of the housing 7 by appropriate means such as adhesion, press-fitting, and welding. Then, after the shaft member 2 is inserted into the inner periphery of the bearing body 8, the first flange portion 9 and the second flange portion 10 are placed in a state where a predetermined axial gap is secured so as to sandwich the bearing body 8. It is bonded and fixed to the outer periphery of the circumferential groove 2c. When the assembly of the hydrodynamic bearing device 1 is completed in this way, the internal space of the housing 7 sealed with the flange portions 9 and 10 includes the internal pores of the both bearing sleeves 81 and 81, for example, lubricating oil. To charge. Filling the lubricating oil can be performed, for example, by immersing the hydrodynamic bearing device 1 that has been assembled in the lubricating oil in a vacuum chamber and then releasing it to atmospheric pressure.

  In the hydrodynamic bearing device 1 having the above configuration, when the shaft member 2 rotates, the radial bearing surface A of the inner peripheral surface 81a of the both bearing sleeves 81 faces the outer peripheral surface 2a1 of the shaft portion 2a via the radial bearing gap. . As the shaft member 2 rotates, a dynamic pressure of lubricating oil is generated in each radial bearing gap, and the shaft member 2 is supported in a non-contact manner in a radial direction by the pressure. As a result, the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft member 2 in a non-contact manner so as to be rotatable in the radial direction are formed.

  Further, when the shaft member 2 rotates, a region (first dynamic pressure groove region) that becomes the thrust bearing surface B of the upper end surface 81b of the upper bearing sleeve 81 is separated from the lower end surface 9b of the first flange portion 9 and a predetermined first. A region (second dynamic pressure groove region) that faces the thrust bearing surface C of the lower end surface 81c of the lower bearing sleeve 81 is opposed to the upper end surface 10b of the second flange portion 10 through the first thrust bearing gap. Opposing via a predetermined second thrust bearing gap. As the shaft member 2 rotates, dynamic pressure of lubricating oil is generated in each thrust bearing gap, and the shaft member 2 is supported in a non-contact manner so as to be rotatable in both thrust directions. Thereby, the 1st thrust bearing part T1 and the 2nd thrust bearing part T2 which non-contact-support the shaft member 2 rotatably in both thrust directions are formed.

  By the way, during operation of the hydrodynamic bearing device 1, there are cases in which bubbles are generated due to the generation of local negative pressure, lubrication oil leaks or vibrations occur due to the generation of bubbles. On the other hand, in the present embodiment, the axial groove 81d1 of the both bearing sleeves 81, 81, the axial groove 82d1 of the spacer member 82, the bearing gaps (the radial bearing gaps of the first and second radial bearing portions R1, R2, Thrust bearing gaps of the first and second thrust bearing portions T1 and T2) and a gap between the inner peripheral surface 82a of the spacer member 82 and the outer peripheral surface 2a of the shaft member 2 are arranged in series inside the hydrodynamic bearing device 1. Thus, the lubricating oil flows and circulates through the circulation channel during the bearing operation. Thereby, the said malfunction is prevented effectively. Further, one end of the axial groove 81d1 of the both bearing sleeves 81 communicates with the seal spaces S1 and S2 on the atmosphere release side, respectively. Therefore, even when bubbles are mixed in the lubricating oil for some reason, the bubbles are discharged to the outside air release side when circulating along with the lubricating oil, so that adverse effects due to the bubbles are more effectively prevented.

  As described above, in the present invention, the bearing sleeve has the first dynamic pressure groove region formed of the dynamic pressure groove 81b1 on the upper end surface 81b and the second dynamic pressure groove region formed of the dynamic pressure groove 81c1 on the lower end surface 81c. In other words, the bearing body 8 is constituted by using two identical bearing sleeves. Accordingly, the bearing sleeve 81 can be assembled to the housing 7 without considering the vertical positional relationship of the bearing sleeves 81, and the dynamic pressure bearing device 1 cannot be used due to a wrong assembly, while avoiding the problem that the bearing body 8 can be used. By providing the thrust bearing portions T1 and T2 on both ends, the hydrodynamic bearing device 1 having excellent moment rigidity can be obtained easily and at low cost. In particular, in this embodiment, the dynamic pressure grooves 81b1 on the upper end surface 81b are arranged in a spiral shape to form a first dynamic pressure groove region, and the dynamic pressure grooves 81c1 on the lower end surface 81c are arranged in a herringbone shape. Since the two dynamic pressure groove regions are formed, it is possible to improve the distinguishability of both end faces and to reliably prevent a situation in which the upper and lower sides of each bearing sleeve 81 are mistakenly assembled.

  In addition, since the two types of bearing sleeves can be integrated into one type of bearing sleeve, the unit unit price can be reduced and the management cost of the components can be reduced.

  In the present embodiment, a dynamic pressure groove arranged in a spiral shape is formed on the thrust bearing surface B (first dynamic pressure groove region) facing the first thrust bearing gap of the first thrust bearing portion T1, and the second thrust is formed. The thrust bearing surface C (second dynamic pressure groove region) facing the second thrust bearing gap of the bearing portion T2 is formed with dynamic pressure grooves arranged in a herringbone shape. For example, the first dynamic pressure groove region and the second dynamic pressure groove region may be configured by dynamic pressure grooves arranged in the same shape with different numbers of grooves and inclination angles.

  In the above description, the arrangement shape of the dynamic pressure grooves in the first dynamic pressure groove region and the second dynamic pressure groove region has been determined by focusing only on the distinctiveness. For example, the first thrust bearing portion T1 and the second thrust bearing portion The arrangement shape of the dynamic pressure grooves, the number of grooves, and the like can be varied according to the pressure required in T2.

  In this embodiment, since the non-porous spacer member 82 is interposed between the bearing sleeves 81, 81, the amount of lubricating oil can be reduced as compared with the case where the bearing body 8 is composed of only the bearing sleeve 81. Can do. Thereby, the axial direction dimension of the 1st and 2nd flange parts 9 and 10 can be shortened, and the bearing span of radial bearing part R1 and R2 can also be expanded.

  Although not shown, in the hydrodynamic bearing device 1 having the above-described configuration, either the first or second flange portion 9 or 10 can be formed integrally with the shaft member 2, and this configuration is adopted. As a result, the assembly of the hydrodynamic bearing device 1 can be further simplified.

  In the above description, the case where the dynamic pressure generating means (dynamic pressure groove) for generating fluid dynamic pressure in the radial bearing gap is provided on the inner periphery of the bearing sleeve 81 has been described. You may provide in the outer peripheral surface 2a of the shaft member 2 which opposes via. In this case, since the positional relationship between the upper and lower bearing sleeves does not affect the rotational performance, the dynamic pressure groove for forming the first radial bearing portion R1 and the dynamic pressure groove for forming the second radial bearing portion R2 are used. May have different shapes or the like.

  FIG. 4 shows another embodiment of the hydrodynamic bearing device according to the present invention. The hydrodynamic bearing device 1 differs from the hydrodynamic bearing device 1 shown in FIG. 2 mainly in that the bearing body 8 is composed of only two bearing sleeves 81 and 81. At this time, when the dynamic pressure groove is provided on the inner peripheral surface 81a of the bearing sleeve 81, the shape of the dynamic pressure groove 81a2 is, for example, a plurality of axial directions provided at equal intervals in the circumferential direction as shown in FIG. If the groove shape is adopted, as in the configuration shown in FIG. 2, assembly can be performed without considering the vertical positions of the two bearing sleeves 81, 81. The radial bearing portions R1 and R2 configured by the dynamic pressure groove 81a2 in this form are so-called step bearings. Of course, when the dynamic pressure grooves for forming the radial bearing portions R1 and R2 are provided on the outer peripheral surface 2a of the shaft member 2, the shape can be freely set as described above. Other configurations and operations are the same as those in the embodiment shown in FIG. 2, and therefore, common reference numerals are given and redundant descriptions are omitted.

  In addition, radial bearing part R1, R2 can also be comprised with what is called a multi-arc bearing which provided the some circular arc surface in the area | region used as a radial bearing surface. Further, as the thrust bearing portions T1 and T2, in addition to generating the dynamic pressure action of the lubricating oil by the dynamic pressure grooves having a herringbone shape or a spiral shape as described above, a plurality of thrust bearing portions T1 and T2 You may employ | adopt what is called a step bearing provided with the radial direction groove | channel at predetermined intervals of the circumferential direction, what is called a wave type bearing (what the step type turned into a wave type), etc.

  In the above description, the lubricating oil is exemplified as the fluid that fills the inside of the hydrodynamic bearing device 1. However, other fluids that can generate dynamic pressure in the bearing gaps, for example, gas such as air Alternatively, a magnetic fluid or the like can be used.

  In the above, an example in which the dynamic pressure bearing device 1 is used by being incorporated in a spindle motor for a disk device has been illustrated. However, the dynamic pressure bearing device 1 having the configuration of the present invention is not limited to a spindle motor for information equipment, It can be preferably used for a motor that rotates and requires high moment rigidity, for example, a fan motor.

  FIG. 6 shows a fan motor incorporating the hydrodynamic bearing device 1 according to the present invention, and in particular, a so-called radial gap type fan motor in which the stator coil 4 and the rotor magnet 5 are opposed to each other through a gap in the radial direction (radial direction). This is a conceptual illustration. In the illustrated motor, the rotor 33 fixed to the outer periphery of the upper end of the shaft member 2 has blades on the outer peripheral surface, and the bracket 36 serves as a casing for housing each component of the motor. The configuration is different from that of the spindle motor shown in FIG. The other constituent members have the same functions and functions as the constituent members of the motor shown in FIG.

It is sectional drawing of the spindle motor for information equipment incorporating the dynamic pressure bearing apparatus. It is sectional drawing of the dynamic pressure bearing apparatus which has a structure of this invention. (A) is a longitudinal sectional view of the bearing sleeve, (b) is a view showing an upper end face of the bearing sleeve, and (c) is a view showing a lower end face of the bearing sleeve. It is sectional drawing which shows other embodiment of a hydrodynamic bearing apparatus. It is a longitudinal cross-sectional view which shows other embodiment of a bearing sleeve. It is sectional drawing of the fan motor incorporating the dynamic pressure bearing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic pressure bearing apparatus 2 Shaft member 4 Stator coil 5 Rotor magnet 7 Housing 8 Bearing main body 9 1st flange part 10 2nd flange part 81 Bearing sleeve 82 Spacer member 81a1, 81b1, 81c1 Dynamic pressure groove R1, R2 Radial bearing part T1 , T2 Thrust bearing part S1, S2 Seal space

Claims (4)

A housing, a bearing body fixed to an inner periphery of said housing, a first and second thrust bearing gap formed respectively between the rotating member to be supported with the one end surface and other end surface of the bearing body, wherein A first dynamic pressure groove region for generating fluid dynamic pressure in the first thrust bearing gap; a second dynamic pressure groove region for generating fluid dynamic pressure in the second thrust bearing gap; and an inner peripheral surface of the bearing body. A radial bearing gap formed by a radial bearing surface, and a radial bearing portion that non-contact-supports the rotating member in a radial direction with fluid dynamic pressure generated in the radial bearing gap ,
The bearing body has two bearing sleeves arranged side by side in the axial direction ;
Each of the two bearing sleeves has the radial bearing surface on the inner peripheral surface, and the first dynamic pressure groove region and the second dynamic pressure groove region on one end surface and the other end surface , respectively , The first dynamic pressure groove region of the other bearing sleeve faces the first thrust bearing gap, and the second dynamic pressure groove region of the other bearing sleeve faces the second thrust bearing gap. Hydrodynamic bearing device.   The hydrodynamic bearing device according to claim 1, wherein the first dynamic pressure groove region and the second dynamic pressure groove region are formed in different shapes.   The hydrodynamic bearing device according to claim 1, wherein a spacer member is interposed between the two bearing sleeves.   A motor comprising the hydrodynamic bearing device according to claim 1, a stator coil, and a rotor magnet.

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