JP2008309579A - Quality determination method of fluid channel in fluid bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a determination method capable of determining properly the quality of formation of a fluid channel constituting a circulation path, in a fluid bearing device of this kind. <P>SOLUTION: A bearing sleeve 8 on which a plurality of axial direction grooves 8c1 are formed previously is stuck and fixed on the inner periphery of a housing 7, and light L1 is irradiated from one end opening side of a bearing member 6 (housing 7) on which a plurality of axial direction channels 10 are formed between the housing 7 and the bearing sleeve 8. In the irradiation light L1, light (passing light L2) passing the inner circumferential surface 8a of the bearing sleeve 8, reflected by the upper bottom surface 7b1 of a bottom part 7b of the housing 7, and passing the channels 10 in the axial direction from the blocking side to the opening side is recognized. Determination on the quality of formation of the channels 10 is performed based on recognition. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for determining the quality of a fluid flow path of a hydrodynamic bearing device.

  The hydrodynamic bearing device supports a shaft member in a relatively rotatable manner with a fluid film formed in a bearing gap. This type of bearing device is particularly excellent in rotational accuracy, quietness, etc. during high-speed rotation, and is suitably used as a bearing device for motors mounted on various electrical devices including information devices. Specifically, as a bearing device for a spindle motor in magnetic disk devices such as HDD, optical disk devices such as CD-ROM, CD-R / RW, DVD-ROM / RAM, magneto-optical disk devices such as MD and MO, etc. Alternatively, it is preferably used as a bearing device for a motor such as a polygon scanner motor of a laser beam printer (LBP), a color wheel motor of a projector, or a fan motor.

  Recently, with the portability and downsizing of the information equipment and the like, there is an increasing demand for downsizing of the hydrodynamic bearing device that is mounted and used.

  For example, for the purpose of reducing the axial dimension (thickness) of the hydrodynamic bearing device, a seal for sealing lubricating oil between the outer peripheral surface of the housing and the inner peripheral surface of the cylindrical portion of the hub facing the housing. A hydrodynamic bearing device is known in which a space is formed and a seal space is disposed radially outside a radial bearing gap formed between a bearing sleeve and a shaft (see, for example, Patent Document 1). In this case, since the thrust bearing gap is provided between the lower end surface of the hub provided at one end of the rotating shaft and the upper end surface of the housing, the rotating shaft may have a constant diameter except for the hub. Has been proposed in which the other end is closed and the other end is closed (see also Patent Document 1).

Further, in this type of hydrodynamic bearing device, a housing and a bearing sleeve fixed to the inner periphery of the housing are provided for the purpose of adjusting the pressure balance in the bearing internal space and removing bubbles mixed in the lubricating oil. An axial flow path may be formed between them. This type of flow path is formed, for example, by providing one or a plurality of axial grooves on the outer periphery of the bearing sleeve in advance and fixing the bearing sleeve to the inner periphery of the housing (see Patent Document 1). By providing such a flow path, a circulation path that allows the lubricating oil to circulate through the flow path, the radial bearing gap, and further the thrust bearing gap and the seal space is configured.
JP 2006-207787 A

  Thus, when the axial flow path that forms a part of the circulation path is formed between the housing and the bearing sleeve, the flow path may not be formed properly depending on the fixing means. That is, when the housing and the bearing sleeve are fixed by bonding, it is difficult to individually adjust the supply amount of the adhesive to be filled between the housing and the bearing sleeve according to the variation in the component dimensions. If it is excessive, the flow path forming the circulation path may be blocked by the adhesive. Further, when both are fixed by press-fitting, unnecessary deformation may occur depending on the variation in the tightening allowance and the accuracy at the time of press-fitting, which may cause the axial groove (flow path) to be deformed and blocked.

  For the above reasons, it is necessary to inspect for these defects during assembly. However, the above-mentioned flow path is usually a small diameter of several tens to several hundreds of micrometers, and these flow paths are visually observed. It is difficult to inspect whether it is formed without deformation or whether the middle is blocked by an adhesive. In particular, as described above, in the hydrodynamic bearing device in which the seal space is disposed on the radially outer side of the radial bearing gap, the sub-assembly in which the bearing sleeve is fixed to the housing closed at one end thereof is used for the flow path. The means for inspecting pass / fail is limited. Further, when a plurality of flow paths are formed, it is necessary to individually determine the quality of the plurality of flow paths. However, it is difficult to appropriately determine the quality of each of the plurality of flow paths by a known method. .

  In view of the above circumstances, an object of the present invention is to provide a determination method capable of appropriately determining the quality of formation of a fluid flow path constituting a circulation path in this type of hydrodynamic bearing device. .

  In order to solve the above problems, the present invention is formed between a housing and a bearing sleeve by fixing a bearing sleeve having a shaft hole to the inner periphery of the housing with the other end closed. A method for determining the quality of one or a plurality of fluid flow paths connected on the end closing side, wherein light is irradiated from one end opening side of the housing, and the light passes through the shaft hole and on the other end closing side. Provided is a fluid flow path quality determination method for a fluid dynamic bearing device that recognizes light that has passed through a fluid flow path due to the wraparound of light and determines the quality of the fluid flow path based on recognition information.

  As described above, the light irradiated from the one end opening side of the housing is recognized as the light passing through one shaft hole and circulated on the other end closing side of the shaft hole passes through the fluid flow path. If a plurality of fluid flow paths are present, the number of light passing through these fluid flow paths when irradiated with light from one light source is good. The number of fluid channels that have been made can be evaluated. In addition, since light passing through the fluid flow path is recognized by using the wraparound of light generated on the closed side of the shaft hole and the light that has reached the multi-end closed side of the shaft hole, The traveling direction is changed while repeating reflection between the housing and the bearing sleeve, and the fluid channel enters the fluid channel from the other end closed side. For this reason, even if the fluid flow path formed between the two is fixed to the housing with the other end closed by fixing the bearing sleeve, the fluid flow path has passed from the closed side to the open side. By recognizing light, it is possible to appropriately evaluate the quality of the fluid flow path.

  When the quality determination of the fluid flow path is performed as described above, the light is shielded between the space from the light source of the irradiation light to the shaft hole and the space from the fluid flow path to the recognition position of the passing light. It is preferable to perform irradiation and recognition. Since both the entrance of the irradiation light in the shaft hole and the exit of the passing light in the fluid flow path are on one end opening side of the housing, the fluid flow path can be obtained by providing an appropriate shielding between the spaces serving as the light entrances and exits. It is possible to reliably recognize only the light passing through the light, and to improve the recognition accuracy and thus the determination accuracy.

  The light that has passed through the fluid flow path by the above means can be recognized directly by visual observation, for example. In this case, the quality can be determined by individually evaluating the degree of penetration of the fluid flow path based on the recognition of the worker (the person who has visually confirmed).

  The recognition of the passing light can also be performed by arranging a light receiving part on the extension line of the passing light and recognizing the passing light by the light receiving part. In this case, the number and form of the passing light recognized by the light receiving unit can be imaged and evaluated, or the physical quantity (for example, light quantity, luminous intensity, etc.) related to the passing light recognized by the light receiving unit is compared with a preset threshold value. Thus, it is possible to determine whether the fluid flow path is good or bad. According to the former method, an image obtained by enlarging the recognition information of the passing light can be recognized, so that the determination can be made more reliably. In addition, according to the latter method, since the process from recognition of passing light to quality determination of the fluid flow path based on the recognition information can be performed automatically and quantitatively, the determination is simple and accurate. As a result, the reliability of the inspection using this method can be improved.

  Regarding the recognition of the passing light, for example, one or a plurality of reflecting surfaces may be provided in front of the traveling direction, and the passing light whose traveling direction is changed by the reflecting surface may be recognized. In this case, the passing light whose traveling direction is changed by one or a plurality of reflecting surfaces may be recognized on the other end closing side of the housing. As described above, by making the position for irradiating light different from the position for recognizing the passing light, each process can be performed while avoiding the overlapping of both work spaces.

  As described above, according to the present invention, it is possible to appropriately determine whether or not the fluid flow path forming the circulation path in the hydrodynamic bearing device is good. Moreover, the reliability of the hydrodynamic bearing device provided through the inspection process using the determination method according to the present invention can be enhanced.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The “up and down” direction in the following description is merely used for easy understanding of the positional relationship between the components in each figure, and the installation direction and usage mode of the hydrodynamic bearing device (dynamic pressure bearing device), or It does not specify an arrangement mode or the like of a work (bearing member) at the time of pass / fail judgment described later.

  FIG. 1 shows a cross-sectional view of a spindle motor for information equipment incorporating a fluid dynamic bearing device 1 which is a target of a determination method according to an embodiment of the present invention. This spindle motor is used in a disk drive device such as an HDD, and is opposed to a hydrodynamic bearing device 1 that supports a rotating body 3 having a shaft 2 in a non-contact manner in a rotatable manner, for example, via a radial gap. A stator coil 4a, a rotor magnet 4b, and a bracket 5 are provided. The stator coil 4 a is attached to the outer diameter side of the bracket 5, and the rotor magnet 4 b is attached to the outer periphery of the hub 9 constituting the rotating body 3. The housing 7 of the hydrodynamic bearing device 1 is fixed to the inner periphery of the bracket 5. Although not shown in the figure, the rotating body 3 holds one or more disk-shaped information recording media (hereinafter simply referred to as disks) such as magnetic disks. In the spindle motor configured as described above, when the stator coil 4a is energized, the rotor magnet 4b is rotated by the exciting force generated between the stator coil 4a and the rotor magnet 4b, and accordingly, the rotor magnet 4b is held by the rotating body 3. The disc is rotated integrally with the shaft 2.

  FIG. 2 shows a cross-sectional view of the hydrodynamic bearing device 1. The hydrodynamic bearing device 1 includes a bearing member 6 mainly composed of a housing 7 and a bearing sleeve 8, and a rotating body 3 that rotates relative to the bearing member 6.

  The rotating body 3 includes a hub 9 disposed on one end opening side of the housing 7 and a shaft 2 inserted into the inner periphery of the bearing sleeve 8.

  The hub 9 is formed of a metal material or a resin material, and includes a disc portion 9a that covers one end opening side (upper side) of the housing 7, a cylindrical portion 9b that extends downward from the outer periphery of the disc portion 9a, and a cylindrical portion. Further, it is composed of a disk mounting surface 9c and a flange 9d provided on the outer periphery of 9b. A disc (not shown) is fitted on the outer periphery of the disk portion 9a and placed on the disc mounting surface 9c. Then, the disc is held on the hub 9 by appropriate holding means (such as a clamper) not shown.

  In this embodiment, the shaft 2 is formed separately from the hub 9, and its upper end is fixed to a hole provided in the center of the hub 9 by means such as press-fitting and bonding. Of course, the shaft 2 can be integrally formed of the same material as the hub 9, or one of the shaft 2 and the hub 9 formed of different materials is used as an insert part and the other is formed by injection molding of metal or resin. You can also.

  The bearing sleeve 8 is formed in a cylindrical shape with a porous body of sintered metal whose main component is copper, for example. The bearing sleeve 8 can also be formed of a porous body made of a non-metallic material such as resin or ceramic, and other than a porous body such as sintered metal, the bearing sleeve 8 is a solid having no internal pores. Or it can also form with the material of the structure which has a hole of the magnitude | size which cannot enter / exit lubricating oil.

A region where a plurality of dynamic pressure grooves are arranged as a radial dynamic pressure generating portion is formed on the entire inner peripheral surface 8a of the bearing sleeve 8 or a part thereof. In this embodiment, for example, as shown in FIG. 3, a region in which a plurality of dynamic pressure grooves 8a1 are arranged in a herringbone shape and a region in which a plurality of dynamic pressure grooves 8a2 are similarly arranged in a herringbone shape are formed in the axial direction. Formed apart. In the upper dynamic pressure groove 8a1 arrangement region, the dynamic pressure groove 8a1 is formed to be axially asymmetric with respect to the axial center m (the axial center of the region between the upper and lower inclined grooves), and above the axial center m. The axial dimension X1 of the array region is formed to be larger than the axial dimension X2 of the lower array region.

  One or a plurality of axial grooves 8 c 1 are formed on the outer peripheral surface 8 c of the bearing sleeve 8 for the purpose of forming an axial flow path 10 to be described later between the bearing sleeve 8 and the housing 7. In this embodiment, as shown in FIG. 4, six axial grooves 8c1 are circularly formed on the outer peripheral surface 8c of the bearing sleeve 8 so that six axial flow paths 10 are formed at equal circumferential intervals. It is formed at equal intervals in the circumferential direction. When the bearing sleeve 8 is formed of sintered metal as in this embodiment, the axial groove 8c1 can be formed at any stage of compacting and various sizing after sintering. However, as will be described later, in consideration of efficiently transmitting light, it is preferable to form them simultaneously during various sizing after sintering. Of course, the axial groove 8c1 may be formed at the time of compacting as long as the surface of the axial groove 8c1 already formed at each sizing can be crushed (recompressed).

  The housing 7 constituting the bearing member 6 together with the bearing sleeve 8 has a shape in which one end thereof is opened and the other end is closed, and is formed in a substantially cylindrical shape with, for example, a metal material. Specifically, the housing 7 integrally includes a cylindrical portion 7a and a bottom portion 7b that closes the other end of the cylindrical portion 7a, and the outer peripheral surface 8c of the bearing sleeve 8 is bonded and fixed to the inner peripheral surface 7c of the cylindrical portion 7a. Do it. Thereby, the bearing member 6 as a sub assembly shown in FIG. 3 is formed. Further, by fixing the bearing sleeve 8 to the housing 7, a plurality of axial grooves 8 c 1 provided on the outer periphery of the bearing sleeve 8, and the inner peripheral surface 7 c of the housing 7 facing the axial grooves 8 c 1 in the radial direction. An axial flow path 10 constituting a circulation path, which will be described later, is formed therebetween.

  At this time, the lower end surface 8b of the bearing sleeve 8 and the upper bottom surface 7b1 of the bottom portion 7b of the housing 7 are bonded and fixed to each other in a non-contact state (a state separated in the axial direction), and between the both surfaces 7b1 and 8b. A gap is formed so that fluid (here, lubricating oil) can flow.

  On the upper end surface 7d located on the one end opening side of the housing 7, as a thrust bearing surface, for example, as shown in FIG. 3, a region in which a plurality of dynamic pressure grooves 7d1 are arranged in a spiral shape is formed. This thrust bearing surface (the region where the dynamic pressure grooves 7d1 are arranged) is opposed to the lower end surface 9a1 of the disk portion 9a of the hub 9, and a thrust of a thrust bearing portion T, which will be described later, between the lower end surface 9a1 when the rotating body 3 rotates. A bearing gap is formed (see FIG. 2).

  On the outer periphery of the housing 7, a tapered sealing surface 7 e that gradually increases in diameter upward is formed. This taper-shaped sealing surface 7e is an annular shape having a radial dimension gradually reduced from the closed side (downward) to the open side (upward) of the housing 7 between the inner peripheral surface 9b1 of the cylindrical portion 9b. A seal space S is formed. The seal space S communicates with the outer diameter side of the thrust bearing gap of the thrust bearing portion T when the shaft 2 and the hub 9 are rotated, and allows the lubricating oil to flow between the bearing inner space including each bearing gap. It is possible. In the state filled with the lubricating oil, the oil level (gas-liquid interface) of the lubricating oil is always maintained in the seal space S at least within the assumed use or transport temperature range.

  Here, as the lubricating oil filled in the fluid dynamic bearing device 1, various oils can be used. As in this embodiment, an ester-based lubricating oil with a low evaporation rate and a low viscosity drop at low temperatures is preferably used as the lubricating oil provided for a hydrodynamic bearing device for a disk drive device such as an HDD. Is done.

  In the hydrodynamic bearing device 1 having the above-described configuration, when the shaft 2 (rotating body 3) is rotated, a region that is the radial bearing surface of the inner peripheral surface 8a of the bearing sleeve 8 (the two dynamic pressure grooves 8a1 and 8a2 are arranged in the upper and lower locations). Is opposed to the outer peripheral surface 2a of the shaft 2 via a radial bearing gap. As the shaft 2 rotates, the lubricating oil in the radial bearing gap is pushed into the axial center m side of each of the dynamic pressure grooves 8a1 and 8a2, and the pressure of the lubricating oil increases in the axial center m side region. To do. The dynamic pressure action of the dynamic pressure grooves 8a1 and 8a2 constitutes the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft 2 in a non-contact manner so as to be rotatable in the radial direction.

  In addition, an oil film of lubricating oil is formed in the thrust bearing gap between the thrust bearing surface of the housing 7 (the region where the dynamic pressure grooves 7d1 are arranged) and the lower end surface 9a1 of the hub 9 facing the housing by the dynamic pressure action of the dynamic pressure grooves 7d1. It is formed. And the thrust bearing part T which non-contact-supports the rotary body 3 in a thrust direction is comprised by the pressure of this oil film.

  Further, the axial flow path 10 is formed between the housing 7 and the bearing sleeve 8, so that the radial bearing gap of the second radial bearing portion R2, the bearing sleeve, from the radial bearing gap of the first radial bearing portion R1. 8 again through the clearance between the lower end surface 8b of the housing 8 and the upper bottom surface 7b1 of the housing bottom 7b, the plurality of axial flow paths 10, and the clearance between the upper end surface 8d of the bearing sleeve 8 and the lower end surface 9a1 of the hub 9. A lubricating oil circulation path is formed which returns to the radial bearing gap (see FIG. 2). By forming the circulation path in this way, even when the pressure balance of the lubricating oil is lost, it is possible to eliminate the pressure difference that is applied immediately, and the generation of bubbles accompanying the generation of local negative pressure, It becomes possible to prevent the leakage of the lubricating oil and the occurrence of vibration caused by the generation. In addition, this circulation path communicates with the seal space S through the thrust bearing gap from the upper end of the axial flow path 10. Therefore, even when bubbles are mixed in the lubricating oil for some reason, the bubbles are discharged to the external space through the seal space S when circulating along with the lubricating oil, so that the above-mentioned problem due to the mixing of bubbles occurs. Can be reliably prevented.

  Since the operation of the circulation path as described above is greatly influenced by the quality of the axial flow path 10 which is a constituent element thereof, it is necessary to provide the quality determination of the flow path 10 as part of the quality inspection of the hydrodynamic bearing device 1. Occurs. Hereinafter, an example of the quality determination method of the flow path 10 will be described with reference to FIG.

  FIG. 5 is a diagram for conceptually explaining an example of a process for determining whether or not the axial flow path 10 formed in the bearing member 6 is good. As shown in the figure, in this determination method, light L1 is irradiated from one end opening side of the bearing member 6 (housing 7), and the inner peripheral surface 8a of the bearing sleeve 8 that forms the shaft hole in the irradiated light L1. And the light (passed light L2) that is reflected by the upper bottom surface 7b1 of the bottom portion 7b of the housing 7 and passes through the axial flow path 10 from the closed side to the open side is recognized. And based on this recognition, the determination regarding the quality of formation of the flow path 10 is performed.

  Specifically, in order to shield the space from the light source of the irradiation light L1 to the shaft hole of the bearing sleeve 8 and the space from the axial flow path 10 to the recognition location of the passing light L2, In a state where one end of the shielding member 21 is in contact with the upper end surface 8d of the bearing sleeve 8, light L1 is emitted from the other end side of the shielding member 21 toward the shaft hole by an appropriate light source. As a result, the light L1 emitted from the light source is prevented from entering the inside of the bearing from the flow path 10 side, and only the light L2 that has passed through the flow path 10 due to the wraparound of light near the bottom portion 7b is on the extension line. To recognize.

  As described above, even if there are a plurality of flow paths 10 as exemplified in the present embodiment, the light L2 that has passed through the axial flow path 10 is recognized and the quality is determined based on this recognition. The number of well formed channels 10 can be evaluated by the number of lights L2 that pass through these channels 10 when the light L1 is irradiated from one light source. Further, light L2 that passes through the flow path 10 by passing through the shaft hole and entering the gap between the lower end surface 8b of the bearing sleeve 8 and the upper bottom surface 7b1 of the bottom portion 7b of the housing 7 from the closed side of the shaft hole is recognized. Thus, the light L2 that has passed through the axial flow path 10 from the closed side to the open side is recognized. Therefore, even when the flow path 10 formed by fixing the bearing sleeve 8 to the housing 7 having the bottom 7b and closed at the other end is to be inspected, it is based on the recognition information of the passing light L2. The quality of the flow path 10 can be evaluated appropriately.

  In the above-described process, the light L2 that has passed through the flow path 10 can be directly recognized visually, and a light receiving portion (for example, a CCD camera illustrated in FIG. 23) and the light receiving unit recognizes the passing light L2.

  Further, when the light receiving unit recognizes the passing light L2, the number and form of the passing light L2 recognized by the light receiving unit can be imaged and evaluated, or a physical quantity related to the passing light L2 recognized by the light receiving unit (for example, The quality of the flow path 10 can also be determined by evaluating the light intensity, light intensity, etc.) by comparing with a preset threshold value. According to the former method, the information obtained by enlarging the recognition information of the passing light L2 on a monitor or the like can be recognized, so that the determination can be made more reliably. Further, according to the latter method, since the process from the recognition of the passing light L2 to the quality determination of the flow path 10 based on the recognition information can be performed automatically and quantitatively, the determination (inspection) is easy and The accuracy can be improved, and as a result, the reliability of the inspection using this method can be improved. In particular, if the physical quantity related to the passing light L2 is acquired for each light L2 that has passed through each flow path 10, the quality determination for each flow path 10 can be performed automatically and at high speed. Of course, it is possible to make a reliable judgment (inspection) with respect to the quality of the formation of the flow path 10 only by the number of recognized passing lights L2.

  In addition, the light quantity (luminous intensity) of the light L1 to be irradiated is the material of the housing 7 and the bearing sleeve 8 to be reflected when passing, the surface roughness, the length (axial dimension) of the flow path 10, and the recognition method of the passing light L2. It is preferable to set appropriately according to the evaluation (determination) method. Various light sources can be used without any particular limitation. For example, a light source capable of irradiating light with a relatively short wavelength is suitable, and a specific example thereof is a halogen lamp. .

  Regarding the recognition of the passing light, for example, one or a plurality of reflecting surfaces may be provided in front of the traveling direction, and the passing light whose traveling direction is changed by the reflecting surface may be recognized. FIG. 6 shows another example of the quality determination method for the flow path 10 according to the present invention. As shown in FIG. 6, the light L2 that has passed through the flow path 10 is reflected on the outer periphery of the shielding member 21. A reflecting member 22 for changing the traveling direction is attached. Here, the reflecting member 22 is disposed on the inner diameter side reflecting surface (first reflecting surface 22a) that first reflects the passing light L2, and on the outer diameter side of the reflecting surface 22a, and has reflection angles different from each other. And a surface (second reflecting surface 22b). In this embodiment, the first reflecting surface 22a has an inclination angle (incident angle) of 45 ° with respect to the traveling direction of the passing light L2, and the second reflecting surface inclined 90 ° with respect to the reflecting surface 22a. The arrangement position (posture) with respect to the bearing member 6 (flow path 10) is set so as to be incident and reflected on the reflecting surface 22b with an incident angle of 45 °.

  Thus, by reflecting the passing light L2 on the reflecting surface 22a (or reflecting surface 22b) and changing its traveling direction, the light irradiation direction and the recognition direction can be made different. In the example of FIG. 6, the light L2 that has passed through the flow path 10 is reflected by the first reflecting surface 22a, and the reflected passing light (reflected light) L3 is reflected by the second reflecting surface 22b. The CCD camera 23 can receive and recognize the passing light L4 which is parallel to the passing light L2 before reflection and whose traveling direction is opposite. For this reason, each process can be performed while avoiding an overlap between the installation space of the light source and the installation space of the light receiving unit (CCD camera 23 in FIG. 6). Alternatively, even when the reflecting member 22 having only the first reflecting surface 22a is used, the light receiving unit such as the CCD camera 23 is moved in the circumferential direction on the extension line of the traveling light L3 reflected by the first reflecting surface 22a. By receiving the light while doing so, it is possible to recognize and determine the passing light L3.

  Moreover, the determination method demonstrated above is applicable not only to the fluid dynamic bearing apparatus 1 of the said illustration but the hydrodynamic bearing apparatus which makes | forms various forms.

  For example, with respect to the axial flow path 10 constituting the circulation path, the flow path 10 does not necessarily need to have a constant dimension over the axial direction. Depending on the main circulation direction and the position that should be preferentially retained, the flow path in which a plurality of partial flow paths having different flow path diameters (sizes) are continuously provided in the axial direction is to be determined. Is also possible. Alternatively, as long as light can pass, a flow path having a bent portion in the middle can also be determined.

  In addition, the fixing means for the bearing sleeve 8 is not particularly limited, and appropriate means such as press-fitting and welding can be used in addition to the exemplified bonding (including the press-fitting adhesion in addition to the loose bonding). In addition, the determination method according to the present invention can be applied to these subassemblies (bearing members 6).

  In the above description, the case where the determination method according to the present invention is applied to the housing 7 in which the bottom portion 7b is integrally formed has been described. However, the bottom portion 7b is formed separately and the housing is fixed later. Of course, the present invention can be applied.

  In the above description, the case where the quality of the flow path 10 formed between the housing 7 and the bearing sleeve 8 is determined is determined. However, if the method according to the present invention is used, the two members 7, It is also possible to determine whether or not the bonding between the eight is good and whether or not the press-fitting is good (whether bonding or press-fitting is performed without a gap).

It is sectional drawing of the spindle motor incorporating the dynamic pressure bearing apparatus which concerns on one Embodiment of this invention. It is sectional drawing of a hydrodynamic bearing apparatus. It is sectional drawing of the bearing member formed by fixing a bearing sleeve to a housing. It is the top view which looked at the bearing member from the one end opening side. It is sectional drawing which shows notionally an example of the quality determination process of the fluid flow path formed between a housing and a bearing sleeve. It is sectional drawing which shows notionally other examples of the quality determination process of a fluid flow path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic pressure bearing apparatus 2 Shaft 6 Bearing member 7 Housing 7b Bottom part 7b1 Upper bottom surface 7c Inner peripheral surface 8 Bearing sleeve 8b Lower end surface 8c Outer peripheral surface 8c1 Axis direction groove | channel 10 Flow path 21 Shielding member 22 Reflective member 22a, 22b Reflective surface 23 CCD Camera L1 Irradiation light L2, L3, L4 Passing light

Claims (9)

One or more formed between the housing and the bearing sleeve by fixing a bearing sleeve having a shaft hole to the inner periphery of the housing with the other end closed and connected to the shaft hole and the other end closed side A method for determining the quality of the fluid flow path of
Light is irradiated from one end opening side of the housing, and the light passing through the fluid flow path by the wraparound of the light passing through the shaft hole and occurring at the other end closing side is recognized, and the recognition information A fluid passage quality determination method for a fluid dynamic bearing device that determines the quality of the fluid flow path based on the above.   The light irradiation and recognition are performed in a state where a space between a light source of the irradiation light from the light source to the shaft hole and a space from the fluid flow path to the recognition position of the passing light is shielded. A method for determining the quality of a fluid flow path.   The fluid passage quality determination method according to claim 1, wherein the passage light is recognized visually.   The fluid passage quality determination method according to claim 1, wherein recognition of the passing light is performed by a light receiving unit disposed on an extension line in the traveling direction of the passing light.   The fluid passage quality determination method according to claim 4, wherein the number and form of the passing light recognized by the light receiving unit are imaged and evaluated.   The fluid channel quality determination method according to claim 4, wherein the quality of the fluid channel is determined by evaluating a physical quantity related to the passing light recognized by the light receiving unit in comparison with a preset threshold value.   5. The fluid flow path quality determination according to claim 3 or 4, wherein one or a plurality of reflecting surfaces are provided in front of the traveling direction of the passing light, and the passing light whose traveling direction is changed by the reflecting surface is recognized. Method.   The fluid passage quality determination method according to claim 7, wherein recognition of the passing light whose traveling direction is changed by the reflecting surface is performed on the other end closing side of the housing.   A fluid bearing device inspection method using the determination step according to claim 1.

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