JP3940451B2 - Hydrodynamic bearing device and motor equipped with the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention utilizes a fluid made of lubricating oil (referred to as “lubricating fluid”), generates pressure on the lubricating fluid filled between the shaft member and the sleeve member during relative rotation, and supports the shaft member by the fluid pressure. The present invention relates to a hydrodynamic fluid bearing device and a motor including the same.
[0002]
[Prior art]
Conventionally, as a hydrodynamic bearing device, a shaft member having a shaft portion and a flange portion projecting radially outward from the shaft portion, a sleeve member that is rotatable relative to the shaft member, and a shaft A device having a lubricating fluid filled in a space defined between a member and a sleeve member is known. In this type of hydrodynamic bearing device, a radial dynamic pressure groove is provided on one or both of the outer peripheral surface of the shaft portion of the shaft member and the inner peripheral surface of the sleeve member facing the shaft member. The gap between the inner peripheral surface of the sleeve member is filled with a lubricating fluid. Also, a thrust dynamic pressure fluid groove is provided on one or both of both surfaces of the flange portion of the shaft member and the inner surface of the sleeve member facing the both surfaces, and the gap between both surfaces of the flange portion and the inner surface of the sleeve member is lubricated. Filled with fluid.
[0003]
Such a hydrodynamic fluid bearing device is often used for various motors such as a DC brushless motor for driving a hard disk of a microcomputer or a CD-ROM driving motor. And one of the sleeve members is coupled to the stator and the fixed portion of the motor, and the other is coupled to the rotor. In addition, motors include a fixed shaft type in which the shaft is fixed and the rotor rotates relative to it, and a rotary shaft type in which the shaft rotates together with the rotor. In the fixed shaft type, the shaft is like the base plate of the motor. The sleeve member is fixed to the fixed portion and is coupled to the rotor so as to rotate integrally. In the shaft rotation type, the sleeve member is fixed to the fixing portion of the motor, and the shaft member is connected to the rotor.
[0004]
[Problems to be solved by the invention]
In such a hydrodynamic bearing device and a motor including the same, it is an important problem to maintain the lubricating fluid filled in the gap between the shaft member and the sleeve member. That is, the lubricating fluid may thermally expand at a high temperature and overflow from the gap, evaporate, scatter by impact, or leak to the outside due to bleeding known as migration.
[0005]
An object of the present invention is to provide a hydrodynamic bearing device capable of enhancing the sealing effect of a lubricating fluid, and capable of recovering the scattered lubricating fluid even if the lubricating fluid is scattered, and a motor including the same. That is.
[0006]
[Means for Solving the Problems]
According to one aspect of the present invention, a shaft member having a shaft portion and a disk-shaped flange portion that protrudes radially outward from the shaft portion and rotates integrally with the shaft portion; One end of the axial direction is closed and the other end is open. A sleeve member that fits the shaft portion and the sleeve at a predetermined interval with the shaft member, surrounds the flange portion, and is rotatable relative to the shaft member, and the sleeve member and the shaft member A motor including a hydrodynamic fluid bearing device including a lubricating fluid filled in a gap between
A radial dynamic pressure groove is provided on one or both of the shaft portion of the shaft member and the mutually opposing surfaces of the sleeve member,
A thrust dynamic pressure groove is provided on one or both of one surface of the flange portion of the shaft member and the first facing surface of the sleeve member facing the flange portion,
One or both of the other surface of the flange portion of the shaft member and the second facing surface of the sleeve member that opposes the radial direction in a relatively wide range from a position close to the shaft portion to the periphery of the flange portion. A taper is formed in which the interval narrows toward the outside,
The gap between the sleeve fitting portion of the sleeve member and the shaft member in the portion surrounding the flange portion is , The other end side Forming a continuous space that is open to the outside only, and the lubricating fluid is continuously filled from the gap of the sleeve fitting portion to the gap of the circumferential surface of the flange,
A stator is integrally provided on one of the shaft member and the sleeve member, and a rotor magnet is provided on the other so as to rotate integrally. The stator and the rotor magnet include the thrust dynamic pressure groove. There is provided a motor having a relative positional relationship in which a magnetic back pressure in a direction opposite to a thrust supporting force that is balanced with a thrust supporting force generated by the above is applied to the shaft member.
[0007]
According to another aspect of the present invention, a shaft member having a shaft portion and a disk-shaped flange portion that protrudes radially outward from the shaft portion and rotates integrally with the shaft portion; One end of the axial direction is closed and the other end is open. A sleeve member that fits the shaft portion and the sleeve, surrounds the flange portion, and is rotatable relative to the shaft member with a predetermined interval between the shaft member, the sleeve member and the shaft member A hydrodynamic bearing device comprising a lubricating fluid filled in a gap between
A radial dynamic pressure groove is provided on one or both of the shaft portion of the shaft member and the mutually facing surfaces of the sleeve member, and one surface of the flange portion of the shaft member and the first facing surface of the sleeve member facing the one surface. Thrust dynamic pressure groove is provided in one or both of the
One or both of the other surface of the flange portion of the shaft member and the second facing surface of the sleeve member that opposes the radial direction in a relatively wide range from a position close to the shaft portion to the periphery of the flange portion. A taper is formed in which the interval narrows toward the outside,
The gap between the sleeve fitting portion of the sleeve member and the shaft member in the portion surrounding the flange portion is , The other end side Forming a continuous space that is open to the outside only, and the lubricating fluid is continuously filled from the gap of the sleeve fitting portion to the gap of the peripheral surface of the flange,
A dynamic pressure fluid bearing device is provided in which a force in a direction opposite to a thrust support force that balances a thrust support force generated by the thrust dynamic pressure groove is applied to the shaft member.
[0008]
According to another aspect of the present invention, a shaft member having a shaft portion and a disk-shaped flange portion that protrudes radially from the shaft portion and rotates integrally with the shaft portion; One end of the axial direction is closed and the other end is open. A sleeve member that is fitted with a shaft portion and a sleeve, surrounds the flange portion with a predetermined interval between the shaft member, and is rotatable relative to the shaft member; The other end side And a lubricating fluid filled to a predetermined level in a continuous gap from the sleeve fitting portion to the flange surrounding portion between the sleeve member and the shaft member which is a space opened to the outside only in In the fluid bearing device,
Radial dynamic pressure bearing means is provided in the sleeve fitting portion,
Thrust dynamic pressure bearing means is provided on the inner surface side of the flange portion and the portion of the facing surface of the sleeve member facing the flange portion,
The outer surface of the flange portion cooperates with the facing surface of the sleeve member facing the flange portion to form a taper seal structure that seals the lubricating fluid by surface tension, and is used as a lubricating fluid reservoir,
There is provided a dynamic pressure fluid bearing device comprising means for causing the shaft member to act on a force balanced with a thrust support force of the thrust dynamic pressure bearing means on the inner surface side of the flange portion.
[0009]
According to still another aspect of the present invention, a shaft member having a shaft portion and a disc-shaped flange portion that projects radially from the shaft portion and rotates integrally with the shaft portion; One end of the axial direction is closed and the other end is open. A sleeve member that is fitted with a shaft portion and a sleeve, surrounds the flange portion with a predetermined interval between the shaft member, and is rotatable relative to the shaft member; The other end side A lubricating fluid filled up to a predetermined level in a continuous gap from the sleeve fitting portion to the flange surrounding portion between the sleeve member and the shaft member which is a space opened to the outside only in the shaft, and the shaft member and A stator coupled to one of the sleeve members, and a rotor magnet coupled to rotate integrally with the other of the shaft member and the sleeve member;
Radial dynamic pressure bearing means is provided in the sleeve fitting portion,
Thrust dynamic pressure bearing means is provided on the inner surface side of the flange portion and the portion of the facing surface of the sleeve member facing the flange portion,
The outer surface of the flange portion cooperates with the facing surface of the sleeve member facing the flange portion to form a taper seal structure that seals the lubricating fluid by surface tension, and is used as a lubricating fluid reservoir,
The stator and the rotor magnet are arranged in a relative positional relationship such that a magnetic force that balances a thrust support force of the thrust dynamic pressure bearing means on the inner surface side of the flange portion is applied to the shaft member. A motor is provided.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment in which a hydrodynamic bearing device according to the present invention is used in a DC brushless spindle motor for driving a hard disk of a microcomputer. In FIG. 1, the illustrated spindle motor includes a base plate 2. The base plate 2 has a circular plate body 4, and a peripheral side wall 6 extending upward is provided on the outer periphery of the plate body 4, and the outer end of the peripheral side wall 6 is attached to project outward in the radial direction. A flange 8 is provided. Although not shown, the mounting flange 8 is attached to a base member of a disk drive device such as a hard disk drive device by a fixing screw. A rotor 10 is rotatably supported on the base plate 2 via a hydrodynamic bearing device 11. The rotor 10 includes a cylindrical hub body 12. At the lower end of the hub body 12, there is provided a disk mounting portion 14 that protrudes outward in the radial direction, and a plurality of recording disks such as magnetic disks are attached to the disk mounting portion 14 at a predetermined interval. A rotor magnet 16 is attached to the inner peripheral surface of the hub body 12, and a stator 18 is disposed on the base plate 2 so as to face the rotor magnet 16. The stator 18 includes a stator core 20 in which a plurality of core plates are stacked, and a coil 22 wound around the stator core 20. Thus, when the current is supplied to the coil 22 of the stator 18, the rotor 10 is rotationally driven in a predetermined direction by the mutual magnetic action of the stator 18 and the magnet 16.
[0011]
Next, the dynamic pressure fluid bearing device 11 will be described. The illustrated dynamic pressure fluid bearing device 11 includes a combination of a shaft member 24 and a sleeve member 26. The shaft member 24 has an elongated shaft portion 28 having a circular cross section, and a disk-shaped member 30 is integrally provided in the vicinity of the other end portion of the shaft portion 28, and the disk-shaped member 30 extends in the radial direction from the shaft portion 28. A flange portion 32 protruding outward is formed. In the embodiment, the shaft portion 28 and the disk-shaped member 30 are integrally formed, but they may be formed separately and fixed. The rotor 12 is fixed to the other end protruding beyond the flange portion 32 of the shaft portion 28 of the shaft member 24 by means such as press fitting. Accordingly, the shaft member 24 is fixed to the rotor 10 and rotated in a predetermined direction integrally with the rotor 12 with respect to the base plate 2.
[0012]
The shaft portion 28 of the shaft member 24 is formed with an injection hole 34 extending from one end (lower end) to the upper end. In the embodiment, one end of the injection hole 34 opens at the lower end surface of the shaft portion 28, the other end opens at the upper end surface of the shaft portion 28, and extends linearly in the axial direction from the one end opening to the other end opening. Yes. A tapered portion 34a having a small diameter in the injection direction of the lubricating fluid such as oil is provided at the upper end in the axial direction of the injection hole 34, and the inner diameter of the injection hole 34 is increased above the tapered portion 34a. The inner diameter of the injection hole 34 is somewhat smaller on the lower side. The filling of the lubricating fluid through the injection hole 34 will be described later.
[0013]
The sleeve member 26 includes a hollow cylindrical sleeve member main body 36. The sleeve member main body 36 has a small inner diameter portion 38 having a small inner diameter, a medium inner diameter portion 40 having an inner diameter larger than the small inner diameter portion 38, and a large inner diameter portion 42 having an inner diameter larger than the medium inner diameter portion 40. The medium inner diameter portion 40 and the large inner diameter portion 42 are disposed in this order from one end portion (lower end portion) of the sleeve member main body 36 toward the other end portion (upper end portion). The inner diameter of the small inner diameter portion 38 is set somewhat larger than the outer diameter of the shaft portion 28 of the shaft member 24, and the inner diameter of the medium inner diameter portion 40 is set somewhat larger than the outer diameter of the flange portion 32 of the shaft member 24. . When the shaft member 28 is attached to such a sleeve member main body 36, the shaft portion 28 of the shaft member 24 is fitted into the small inner diameter portion 38 of the sleeve member main body 36 (fitting in a relatively long region in the axial direction of the shaft member 24). In addition, the flange portion 30 of the shaft member 24 is disposed on the inner diameter portion 40 of the sleeve member main body 36, and the small inner diameter portion 38, the shoulder portion 46, and the medium inner diameter portion 40 of the sleeve member main body 36 are connected to the shaft. A gap for the lubricating fluid is provided between the shaft portion 28 of the member 24 and one surface and the peripheral surface of the flange portion 32.
[0014]
The cap member 44 is attached and fixed to the large inner diameter portion of the sleeve member main body 36 so as to rotate integrally with the sleeve member main body 36, and forms a part of the sleeve member main body 36. The cap member 44 covers the outer surface of the flange portion 32 of the shaft member 24, and includes a middle inner diameter portion 40 of the sleeve member main body 36, and a shoulder portion 46 that defines the boundary between the inner inner diameter portion 40 and the large inner diameter portion 42. The cap member 44 constitutes a flange surrounding portion that surrounds almost the entire surface of the flange portion 32. In relation to the cap member 44, the shoulder 46 is provided with an annular recess, and an O-ring 48 is disposed in the annular recess. The O-ring 48 can be formed of, for example, synthetic rubber and seals between the cap member 44 and the sleeve member main body 36. The cap member 44 is fixed to the sleeve member main body 36 by means such as caulking.
[0015]
A closing member 50 is attached to one end portion (lower end portion in FIG. 1) of the sleeve member 26 so as to face one end portion of the shaft portion 28 of the shaft member 24 via a gap. The closing member 50 is composed of a circular plate-like member, and is fixed to an annular recess formed on one end surface (lower end surface) of the sleeve member main body 36 by means such as caulking. By providing the closing member 50 in this way, the small inner diameter portion 38 is closed at one end of the sleeve member 26, and the sleeve member 26 defines an accommodation space in which the one end is closed. As shown in FIG. 1, the defined accommodation space surrounds one end portion of the shaft portion 28 of the shaft member 24, and this accommodation space communicates with the gap of the sleeve fitting portion. In the motor having such a configuration, the space between the sleeve member 26 and the shaft member 24 (this space is filled with the lubricating fluid) is opened to the outside at the other end (the large inner diameter portion 42 side) of the sleeve member 26. Therefore, it is only necessary to consider the leakage of the lubricating fluid from the other end side of the sleeve member 26.
[0016]
In the present embodiment, the thrust dynamic pressure bearing means and the radial dynamic pressure bearing means are arranged as follows. The radial dynamic pressure bearing means 52 and 54 are disposed at a distance in the axial direction between the shaft portion 28 of the shaft member 24 and the sleeve fitting portion of the sleeve member 26, and support the radial force acting on the shaft member 24. To do. The portion of the shaft portion 28 of the shaft member 24 between the pair of radial dynamic pressure bearing means 52 and 54 has a slightly smaller diameter than the other portions. The dynamic pressure grooves of the radial dynamic pressure bearing means 52 and 54 may be in the form of a herringbone, a spiral, or the like, and are formed on the inner peripheral surface of the small inner diameter portion 38 of the sleeve member 26 as indicated by a broken line in FIG. . Instead of providing the radial dynamic pressure groove on the inner peripheral surface of the sleeve member 26, for example, the radial dynamic pressure groove may be provided on the outer peripheral surface of the shaft portion 28 of the shaft member 24, or the inner peripheral surface of the sleeve member 26 and the shaft member 24. You may provide in both the outer peripheral surfaces of the axial part 28 of this. The thrust dynamic pressure bearing means 56 is provided on the inner surface of the flange portion 32 of the shaft member 24 (one surface on the lower side in FIG. 1), and supports the thrust force acting on the shaft member 24. The dynamic pressure groove of the thrust dynamic pressure bearing means 56 may be in the shape of a herringbone, a spiral or the like, and is formed on the inner surface of the flange portion 32 as indicated by a broken line in FIG. Instead of providing the thrust dynamic pressure groove on the inner surface of the flange portion 32, the opposing surface of the sleeve member 26 facing this one surface of the flange portion 32, that is, the small inner diameter portion 38 and the medium inner diameter portion of the sleeve member 26. 40 may be provided on the surface of the shoulder portion 58 (which constitutes the first opposing surface) between the flange portion 32 and the surface of the shoulder portion 58 of the sleeve member 32. You may do it.
[0017]
In the embodiment, a taper seal is formed on the inner surface of the cap member 44 (which constitutes the second opposing surface of the sleeve member 26) that faces the outer surface of the flange portion 32 of the shaft member 24 (the other surface on the upper side in FIG. 1). A taper 60 constituting the structure is provided. The taper 60 has a gap between the taper 60 and the flange portion 32 that is radially outward, and defines an annular taper space facing the other surface of the flange portion 32. The taper 60 applies a force directed outward in the radial direction to the lubricating fluid by surface tension. In the taper 60, the gap between the cap member 44 and the flange portion 32 is reduced outward in the radial direction. Therefore, when the shaft member 24 and the sleeve member 26 are rotated relative to each other by the rotation of the motor, the lubricating fluid of the taper 60 is obtained. In addition, the outward force in the radial direction is also exerted by the centrifugal force generated by the rotation, and the movement of the lubricating fluid in the leakage direction (inward in the radial direction) is reliably prevented. The radial outward force due to the centrifugal force also acts when the lubricating fluid radiates inward in the radial direction (so-called migration), the mist of the lubricating fluid, the scattering due to the impact, etc., and the lubricating fluid (or The fine particles) are collected radially inward by this centrifugal force. The taper 60 can be provided on the outer end surface of the flange portion 32 of the shaft member 24 instead of or together with the inner surface of the cap member 44, but can be easily formed by being provided on the cap member 44. In the present embodiment, a relatively wide range of at least most of the inner surface of the cap member 44 is provided without providing a thrust dynamic pressure groove in the other surface of the flange portion 32 and the region of the inner surface of the cap member 44 facing the other surface. Since the taper 60 is provided, a relatively large tapered space can be formed, and a sufficient fluid reservoir for the lubricating fluid can be obtained. The taper 60 has a sealing interface for the lubricating fluid, and the taper 60 also has a sealing function. As described above, since the taper 60 is provided by utilizing at least the most region of the flange portion 32 (or the inner surface of the cap member 44 facing this region), even when the temperature rises and the lubricating fluid expands, The taper 60 can absorb thermal expansion, and even if the lubricating fluid evaporates due to long-term use, the lubricating fluid stored in the taper 60 can be used as a replenishing fluid. In the illustrated embodiment, in order to ensure a sufficient tapered space, the open end of the taper 60 is located at a position close to the shaft portion 28 of the shaft member 24, and the peripheral edge of the flange portion 32 from the radially inner position. Is formed in a straight line when viewed in cross-section up to a position facing the. On the radially inner side of the taper 60, an annular groove 61 is formed on the other surface of the flange portion 32 of the shaft member 24, which is located near the base portion of the flange portion 32 of the shaft member 24 to the shaft portion 28. The groove 61 is coated with an oil repellent 63 (FIG. 2) that suppresses the flow of the lubricating fluid. The oil repellent 63 repels the lubricating fluid and prevents the inward flow and bleeding in the radial direction.
[0018]
Such a configuration can be advantageously applied to a relatively small motor, for example, a spindle motor for a hard disk that rotates a magnetic disk having a diameter of 2.5 inches or less, and the dimensions of various components are set as follows. can do. Referring to FIG. 2, for example, the outer diameter D1 of the shaft portion 28 of the shaft member 24 is set to 3.0 to 3.5 mm, the outer diameter D2 of the flange portion 32 is set to 6.0 to 6.5 mm, and the flange portion 32 is The thickness T is set to 1.0 to 1.5 mm, the interval W between the open side end P of the taper 60 and the shaft portion 28 is set to 0.4 to 0.5 mm, and the closed side end Q of the taper 60 is set to the peripheral edge of the flange portion 32. The taper angle α from the closing side Q of the taper 60 to the open end P is set to 20 to 30 degrees.
[0019]
In the present embodiment, as shown in FIG. 1, the lubricating fluid 62 of the hydrodynamic bearing device is such that the seal interface is located at the taper 60, and the shaft member 24 and the sleeve member 26 below the seal interface. It is filled substantially over the entire gap. That is, the lubricating fluid 62 substantially continues from one end surface of the shaft portion 28 of the shaft member 24 (the surface facing the closing member 50) to the taper 60 through the radial dynamic pressure bearing means 52 and 54 and the thrust dynamic pressure bearing means 56. Filled. Therefore, as can be easily understood, the taper 60 for preventing leakage of the lubricating fluid 62 need only be provided at one location, and the structure of the hydrodynamic bearing device and the motor using the same can be simplified. And the possibility of leakage of the lubricating fluid 62 is reduced.
[0020]
Since the lubricating fluid 62 is also filled into one end surface of the shaft portion 28 of the shaft member 24, auxiliary thrust dynamic pressure bearing means 64 may be provided on one end surface of the shaft portion 28. The auxiliary thrust dynamic pressure bearing means 64 is provided to adjust the thrust force of the thrust dynamic pressure bearing means 56 provided on the flange portion 32 of the shaft member 24. The dynamic pressure groove of the thrust dynamic pressure bearing means 64 may be in the shape of a herringbone, a spiral or the like, and is formed on one end surface of the shaft portion 28 as indicated by a broken line in FIG. The auxiliary thrust dynamic pressure groove may be provided on the inner surface of the closing member 50 instead of being provided on the one end surface of the shaft portion 28, and may be provided on both the one end surface of the shaft portion 28 and the closing member 50. It may be.
[0021]
As the auxiliary thrust dynamic pressure bearing means 64, a pump-in type dynamic pressure groove structure is employed when the thrust support force by the thrust dynamic pressure bearing means 56 is increased, that is, when the force to lift the shaft member 28 is increased. In this case, the lubricating fluid 62 flows inward in the auxiliary thrust dynamic pressure bearing means portion 64, and thereby a levitation force acts on the shaft member 24, and thus the rotor 10.
[0022]
The present embodiment is configured as follows in order to discharge the air mixed in the lubricating fluid 62 to the outside. That is, the shaft member 24 is provided with a pressure adjusting channel 66 of the lubricating fluid 62 having an outlet formed on the outer peripheral surface of the flange portion 32 and an inlet formed on one end surface of the shaft portion 28. Specifically, the injection hole 34 formed in the shaft portion 28 is used as a vertical hole of the channel 66, and a communication hole 67 communicating with the injection hole 34 from the outer peripheral surface of the flange portion 32 is formed. The upper part of the injection hole 34 from the communication hole 67 is closed by an elastic plug 70 described later. Here, part or all of the dynamic pressure grooves in the radial dynamic pressure bearing means 52, 54, the thrust dynamic pressure bearing means 58 and the auxiliary thrust dynamic pressure bearing means 64 are such that the lubricating fluid 62 flows from the outlet of the channel 66 to the flange portion 32. The groove shape is devised so as to pass through the circumferential surface and the entire surface of the shaft portion 28, move downward on the outer periphery of the shaft portion 28, and flow into the channel 66 from the end surface, and lubricate through the above-described circulation path including the channel 66. The fluid 62 is circulated. By circulating the lubricating fluid 62 in this way, the fluid pressure generated by the thrust dynamic pressure groove 56 and the radial dynamic pressure grooves 52 and 54 is also adjusted.
[0023]
Further, the gap L1 between the outer peripheral surface of the flange portion 32 and the inner peripheral surface of the inner diameter portion 40 of the sleeve member main body 36 opposed to the flange portion 32 causes the lubricating fluid 62 to flow by capillary action as shown in an enlarged view in FIG. The interval for holding is set to a dimension such as L1 = 50 μm or slightly smaller than that. Therefore, when the bubbles mixed in the lubricating fluid 62 expand due to the temperature rise, the expanded bubbles are guided to the outer peripheral surface of the flange portion 32 by the circulation of the lubricating fluid 62, where the bubbles are separated into air and the lubricating fluid 62, and lubricated. The fluid 62 is circulated again toward the thrust dynamic pressure bearing means 58, and the air passes through between the shaft member 24 and the cap member 44 from the tapered portion 60 and is discharged to the outside.
[0024]
A filter 68 can be disposed in the channel 66 as required. The filter 68 is disposed in the injection hole 34 and can be formed of, for example, a porous material or a fiber material. The filter 68 captures impurities such as wear powder in the lubricating fluid 62, thereby improving the reliability of the hydrodynamic bearing device 11.
[0025]
As shown in detail in FIG. 2, an annular throttle protrusion 69 that protrudes outward in the radial direction is provided on the outer peripheral surface of one side (lower side) of the flange portion 32. A gap L2 between the outer peripheral surface of the throttle protrusion 69 and the inner peripheral surface of the medium inner diameter portion 40 is set to 20 μm, for example. The throttle protrusion 69 cushions the applied impact by moving in the lubricating fluid 62 against the axial impact of the shaft member 24. The throttle protrusion 69 is located below the communication hole 67 in the circulation path of the lubricating fluid 62, and further, the gap L1 is greatly throttled, so that the bubbles are effectively separated from the lubricating fluid 62.
[0026]
In the present embodiment, the stator 18 is mounted on the outer peripheral surface of the sleeve member 26 of the hydrodynamic bearing device 11 and supported by the base plate 2 via the sleeve member 26. Instead, for example, the base plate 2 An annular support wall may be provided, and the stator 18 may be attached to the annular support wall. In relation to the stator 18, the magnetic center between the stator 18 and the rotor magnet 16 attached to the rotor 10 is arranged slightly shifted in the axial direction of the shaft member 24. In other words, the magnetic center of the magnet 16 is arranged somewhat shifted from the magnetic center of the stator 18 in the vertical direction (vertical direction in FIG. 1). Therefore, a biasing force in a direction close to the base plate 2 (a biasing force in a direction in which one end surface of the shaft member 24 is close to the closing member 50) acts on the rotor 10 by the magnetic attraction action of the magnet 16 with respect to the stator 18. . During rotation of the motor, the thrust force generated by the axial dynamic force bearing means 58 on the shaft member 24 to lift upward in FIG. 1 (when the auxiliary thrust dynamic pressure bearing means 64 is provided) 1), the thrust force is balanced with the magnetic biasing force, ie, the magnetic back pressure, that the magnet 16 and the stator 18 try to hold down in FIG. 1, and the rotor 10 is stable in the vertical direction. Rotate. This magnetic biasing force also prevents the rotor 10 from coming off the sleeve member 26.
[0027]
The lubricating fluid 62 can be injected into the dynamic pressure fluid bearing device 11 in a relatively simple and reliable manner, for example, by the following operation. 3 (a) to 3 (d), in order to inject the lubricating fluid 62, first, as shown in FIG. 3 (a), a filter 68 is attached to the injection hole 34, and then the shaft member 24 is attached. The elastic plug 70 is temporarily attached to the formed injection hole 34. The plug 70 can be formed of, for example, synthetic rubber, natural rubber, or the like, and preferably has a shape corresponding to the shape of the tapered portion 34a of the injection hole 34. One end portion of the tapered portion 72 of the elastic plug 70 is provided with a small diameter portion 74 corresponding to the small inner diameter portion of the injection hole 34, and a large diameter portion 76 corresponding to the large inner diameter portion of the injection hole 34 at the other end portion. Is provided. As shown in FIG. 3A, the plug body 70 is temporarily mounted so that the tapered portion 72 is located on the tapered portion 34 a of the injection hole 34 from the rotor 10 side. Thus, when temporarily mounted, the small diameter portion 74 is positioned at the small inner diameter portion of the injection hole 34 and the large diameter portion 76 is positioned at the large inner diameter portion of the injection hole 34. In this temporary mounting state, the lubricating fluid 62 to be injected is plugged. It does not leak from the body 70.
[0028]
Next, as shown in FIG. 3 (b), the hollow needle 78 is inserted through the plug 70 that has been temporarily mounted, and the tip thereof protrudes into the small inner diameter portion of the injection hole 34. Thereafter, the lubricating fluid 62 is passed through the hollow needle 78 to the back side of the plug body 70, that is, the small inner diameter portion of the injection hole 34 and the dynamic pressure space of the dynamic pressure fluid bearing device 11 communicating therewith, that is, the shaft member 24 and the sleeve member. Lubricating fluid 62 is injected into the gap defined between.
[0029]
Next, as shown in FIG. 3C, after the hollow needle 78 is pulled out from the plug body 70, the plug body 70 is pushed in with a rod-shaped pressing tool 82, and as shown in FIG. Is pressed into the small inner diameter portion of the injection hole 34. When the hollow needle 78 is pulled out, a needle penetration mark 80 is generated in the plug 70, and evaporation, leakage, etc. of the lubricating fluid 62 may occur from the needle penetration mark 80 due to long-term use of the dynamic pressure fluid bearing device 11. There is. Therefore, after the hollow needle 78 is pulled out, it is press-fitted into the small inner diameter portion of the injection hole 34. By press-fitting in this way, the large-diameter portion 76 of the plug body 70 is particularly elastically deformed, and the large-diameter portion 76 securely and reliably closes the injection hole 34, and the needle penetration mark 80 in the large-diameter portion 76. Is reliably closed, and evaporation, leakage, etc. of the lubricating fluid 62 through the plug 70 are reliably prevented. It should be noted that the elastic plug body 70 is somewhat elastically deformed when temporarily attached to the injection hole 34, and is preferably greatly elastically deformed when further press-fitted from the temporarily attached state, and may have an appropriate shape such as this.
[0030]
When the plug 70 is press-fitted into the small inner diameter portion of the injection hole 34, the lubricating fluid 62 existing inside thereof is fed into the dynamic pressure space of the radial dynamic pressure bearing means 52, 54 and the thrust dynamic pressure bearing means 56, As shown in FIG. 3D, the lubricating fluid 62 is filled up to a predetermined level from the small inner diameter portion of the injection hole 34 through one end surface of the shaft portion 28 of the shaft member 24, the outer periphery of the shaft portion 28, and the inner surface of the flange portion 32. In this way, when filled to a predetermined level, the sealing interface of the lubricating fluid 62 is located at the taper 60 of the cap member 44. Such an injection operation of the lubricating fluid 62 is preferably performed in a vacuum chamber, and the space into which the lubricating fluid 62 is injected is located on the upper side as shown in FIGS. 3 (a) to 3 (d). In the embodiment, it is desirable to hold the rotor 10 so as to be positioned on the lower side.
[0031]
In the above-described embodiment, the present invention is applied to the shaft rotation type motor. However, the present invention can be similarly applied to the shaft fixed type motor shown in FIG. In FIG. 4 showing a second embodiment of the motor, the illustrated motor includes a base plate 102 and a rotor 104 that is rotatable relative to the base plate 102, and a hydrodynamic fluid is interposed between the base plate 102 and the rotor 104. A bearing device 106 is interposed. The hydrodynamic fluid bearing device 106 in the present embodiment has substantially the same configuration as the hydrodynamic fluid bearing device 11 shown in FIG. 1, and therefore only the differences will be described later.
[0032]
In this embodiment, the dynamic pressure fluid bearing device 106 is used upside down from the application example in the embodiment of FIG. That is, one end of the sleeve member 108 of the hydrodynamic fluid bearing device 106 (the end where the closing member 110 is provided) is coupled to the rotor 104. Further, the protruding end portion of the shaft member 112 (the end portion protruding in the axial direction from the flange portion 116 of the shaft portion 114) is coupled to the base plate 102. The base plate 102 is provided with an annular support wall 118 outside the sleeve member 106, and a stator 120 is attached to the annular support wall 118.
[0033]
In this motor, since the shaft member 112 is fixed to the base plate 102, the sleeve 108 is driven to rotate integrally with the rotor 104 in a predetermined direction with respect to the shaft member 112, and thus the base plate 102.
[0034]
As can be understood from the above description, the hydrodynamic fluid bearing device can be used as a common component, and even in its use, it may be used so that the closing member that closes one end of the sleeve member is located on the upper side. On the contrary, it can also be used so that the closing member is positioned on the lower side, and the same effect is achieved as the dynamic pressure fluid bearing device.
[0035]
Referring to FIG. 5 together with FIG. 4, in this second embodiment, the radial dynamic pressure bearing means 122, 124 are provided at the shaft portion 114 of the shaft member 112, that is, the sleeve fitting portion with the sleeve member 108. Dynamic pressure grooves 126 and 128 of the radial dynamic pressure bearing means 122 and 124 are formed on the outer peripheral surface of the shaft portion 114. Further, the thrust dynamic pressure bearing means 130 is provided on one surface of the flange portion 116 (the upper surface in FIGS. 4 and 5), and the dynamic pressure groove 132 of the thrust dynamic pressure bearing means 130 is formed on this one surface. The groove shapes of the radial dynamic pressure grooves 126 and 128 and the thrust dynamic pressure groove 132 are not clearly shown in FIG. 1, but are similarly formed in the first embodiment.
[0036]
In the second embodiment, the flange portion 116 of the shaft member 112, the outlet is the outer peripheral surface of the flange portion 116, and the inlet is the side where the taper 136 is provided at the base portion of the flange portion 116 with the shaft portion 114. A pressure adjusting channel 138 formed on one surface (inner surface) on the opposite side is provided. In this case, the dynamic pressure groove of the thrust dynamic pressure bearing means 130 formed on one surface of the flange portion 116 is such that the lubricating fluid 124 flows into the channel 138 from the outer periphery of the flange portion 116 through the thrust dynamic pressure bearing means 130. The shape of the channel 138 is devised, and the channel 138 forms a circulation path by the gap between the outer periphery and one surface of the flange portion 116 and the inner surface of the sleeve member 108 opposed to the outer periphery. Therefore, although air bubbles are likely to accumulate in the connecting portion between the shaft portion 114 and the flange portion 116, the inlet of the channel 126 is opened at the root portion of the flange portion 116 to the shaft portion 114, so that the lubricating fluid 124 By circulating through the circulation path, the bubbles are smoothly discharged to the outside in the same manner as described in the first embodiment. As shown in FIG. 5, the inlet of the channel 126 is preferably provided radially inward from the region where the dynamic pressure groove 132 of the thrust dynamic pressure bearing means 130 is formed, and the channel 126 is spaced apart in the circumferential direction. Two or more may be provided. In this second embodiment, the lubricating fluid circulation structure in the first embodiment may be adopted, and on the contrary, the lubricating fluid circulation structure in the second embodiment is changed to the first embodiment. It may be used.
[0037]
In this embodiment, when the auxiliary thrust dynamic pressure bearing means is provided on the end surface (upper surface) of the shaft portion 114, the pump-in type or the pump-out type is considered in consideration of only the balance of the thrust force regardless of the circulation of the lubricating fluid 124. Can be adopted. In the case of the pump-in type, a levitation force can be applied to the rotor 104 as described in the first embodiment. On the other hand, when reducing the thrust supporting force by the thrust dynamic pressure bearing means 130, that is, when reducing the force to lift the shaft member 112, a pump-out type dynamic pressure groove is employed. In this case, the lubricating fluid 123 flows out to the outside in the auxiliary thrust dynamic pressure bearing means, whereby a suction force is applied to the shaft member 112, and thus the rotor 104, toward the end surface of the shaft portion 114.
[0038]
In each of the above-described embodiments, the case where the hydrodynamic bearing is used for the motor has been described. However, it is also possible to use the bearing as a bearing device that supports the rotation shaft in a rotating manner. In such a case, since there is no rotor magnet and stator for causing the shaft member to apply a magnetic force in a predetermined direction that balances the thrust force generated by the thrust dynamic pressure bearing means, a force that balances the thrust force on the shaft member. It is necessary to provide a separate means for acting.
[0039]
In FIG. 6 showing a single use example as a dynamic pressure fluid bearing device, the illustrated dynamic pressure fluid bearing device includes a sleeve member 202 and a shaft member 204 that is rotatable relative to the sleeve member 202. . A closing member 206 is attached to one end of the sleeve member 202. In this example, the shaft member 204 is made of a magnetic material, and a magnet piece 208 is used as means for applying a biasing force to the shaft member 204. The closing member 206 is made of a nonmagnetic material, and a disk-shaped magnet piece 208 is fixed to the outer surface of the closing member 206. A magnetic field from the magnet piece 208 acts on the shaft member 204 through the closing member 206, and a magnetic force in a direction close to the closing member 206 acts on the shaft member 204 by the magnetic action of the magnet piece 208. In this example, radial dynamic pressure bearing means 214 and 216 are provided on the shaft portion 210 of the shaft member 204, and thrust dynamic pressure bearing means 218 is provided on one surface (the lower surface in FIG. 6) of the flange portion 212. The magnetic force generated by the magnet piece 218 is set so as to balance the thrust force generated by the dynamic pressure groove of the thrust dynamic pressure bearing means 218.
[0040]
In this example, the shaft member 204 is provided with a pressure adjusting channel 220. The channel 220 has a vertical hole 200 a that opens in the end surface of the shaft portion 210 of the shaft member 204 and extends in the axial direction, and a communication hole 200 b that extends radially outward from the vertical hole 200 a and opens to the outer periphery of the flange portion 212. It is composed of The lubricating fluid 222 is guided from the end face of the shaft portion 210 through the channel 220 to the outer periphery of the flange portion 212, and further through the gap defined between the flange portion 212 and the shaft portion 210 of the sleeve member 202. It is circulated through a circulation path that reaches the end face of 210. Since the above-described circulation of the lubricating fluid is substantially the same as that of the first embodiment, the same effect as described above is achieved, and the bubbles in the lubricating fluid 222 are discharged to the outside by this circulation. The other structure of the hydrodynamic bearing device is substantially the same as that employed in the first embodiment.
[0041]
In such a support structure by the hydrodynamic bearing device, the shaft member 204 is not shown, but for example, a driving force transmission mechanism such as a pulley and a belt (not shown) is output from a driving source such as an electric motor. Drive-connected to the shaft and driven to rotate in a predetermined direction by the action of a drive source.
[0042]
【The invention's effect】
In the motor according to claim 1 of the present invention, since the taper is formed over a relatively wide range of one or both of the other surface of the flange portion of the shaft member and the second facing surface of the sleeve member facing the flange portion, The tapered space defined by the taper can be made relatively large. This taper has a reservoir function for holding the lubricating fluid in addition to a sealing function by surface tension, and can secure a sufficient space for the lubricating fluid seal interface and the lubricating fluid reservoir. Therefore, even if the temperature rises and the lubricating fluid expands, the taper can absorb the thermal expansion, and even if the lubricating fluid evaporates due to long-term use, the lubricating fluid stored in this taper is replenished. It can be used as a fluid. In addition, since the taper is narrower in the radially outward direction, the lubricating fluid existing in the taper is subjected to a radially outward force due to surface tension, and the shaft member and the sleeve member. The centrifugal force generated when the two parts rotate relative to each other also exerts a radially outward force, and the movement of the lubricating fluid in the leakage direction (inward in the radial direction) is reliably prevented. The outward force in the radial direction due to this centrifugal force is effective even when lubrication fluid bleeds inward in the radial direction (so-called lubrication fluid migration), mist of the lubrication fluid, and scattering due to impact. The lubricating fluid (or fine particles thereof) that moves inward in the radial direction is recovered radially inward by centrifugal force, and leakage due to bleeding, mist, scattering, etc. of the lubricating fluid can be prevented. Further, since the stator and the rotor magnet are in a relative positional relationship such that a magnetic back pressure in a predetermined direction acts on the shaft member, the magnetic back pressure by the magnetic biasing means by the stator and the rotor magnet is generated by the thrust dynamic pressure groove. The thrust force acting on the shaft member is balanced without providing the thrust dynamic pressure bearing means on the other surface side of the flange portion, and the rotor including the rotor magnet can be rotated stably. .
[0043]
In the motor according to the second aspect of the present invention, the sleeve member is provided with a closing member facing the shaft portion of the shaft member, and the sleeve member defines an accommodation space that surrounds the end portion of the shaft member together with the closing member. Since the housing space is continuous with the gap of the sleeve fitting portion, the lubricating fluid may be sealed only on the other surface of the flange portion of the shaft member, and reliably sealed with a relatively simple structure. be able to.
[0044]
In the motor according to the third aspect of the present invention, since the shaft member is provided with a channel that communicates the peripheral surface of the flange portion and the end surface of the shaft portion, the shaft member is filled between the shaft member and the sleeve member. The lubricating fluid is circulated through the channel and through the thrust dynamic pressure bearing means and the radial dynamic pressure bearing means, and the fluid pressure generated by the thrust dynamic pressure bearing means and the radial dynamic pressure bearing means is adjusted. Even if bubbles are mixed in the lubricating fluid, the bubbles mixed by the circulation of the lubricating fluid are guided to the peripheral surface of the flange portion, and are separated into the lubricating fluid and air at the outer periphery of the flange portion. It is discharged outside.
[0045]
In the motor according to the fourth aspect of the present invention, since the pressure adjusting channel is composed of a longitudinal hole extending in the longitudinal direction and a communicating hole communicating with the longitudinal hole and the outer periphery of the flange portion, the channel is formed relatively easily. be able to.
[0046]
In the motor according to claim 5 of the present invention, since the filter is disposed in the vertical hole, impurities mixed in the lubricating fluid can be captured.
[0047]
In the motor according to the sixth aspect of the present invention, the air bubbles mixed in the lubricating fluid are likely to accumulate in the connecting portion between the shaft portion of the shaft member and the flange portion. Since the channels communicate with each other, the accumulated bubbles are guided to the outer periphery of the flange portion through the channel, separated into the lubricating fluid and the air at the outer periphery of the flange portion, and the separated air is discharged to the outside.
[0048]
In the motor according to the seventh aspect of the present invention, the gap between the peripheral surface of the flange portion and the inner peripheral surface of the sleeve member facing the flange portion is set so as to hold the lubricating fluid by capillary action. Air bubbles introduced to the outer periphery of the flange portion are prevented from entering the inside, and the lubricating fluid does not leak.
[0049]
In the motor according to the eighth aspect of the present invention, the side of the flange portion on the side where the thrust dynamic pressure bearing means is provided is provided with a buffering restricting protrusion protruding outward in the radial direction. The relative movement of the shaft member and the sleeve member in the axial direction is buffered by the movement of the throttle protrusion in the lubricating fluid. Further, the flow of bubbles mixed in the lubricating fluid to the thrust dynamic pressure bearing means is also prevented.
[0050]
In the motor according to the ninth aspect of the present invention, the taper can be formed relatively easily since the taper is provided on the lid that covers the thrust part of the sleeve member.
[0051]
In the motor according to the tenth aspect of the present invention, the lubricant is applied to the annular groove provided in the flange portion, so that leakage of the lubricating fluid can be prevented more reliably.
[0052]
In the hydrodynamic bearing device according to an eleventh aspect of the present invention, a taper is formed over a relatively wide range of one or both of the other surface of the flange portion of the shaft member and the second facing surface of the sleeve member facing the other surface. Since this taper is narrower in the radial outward direction, the same action as described above is achieved. In addition, since a force in the opposite direction to the thrust support force generated by the thrust dynamic pressure groove acts on the shaft member, the thrust support force and the force in the opposite direction are balanced, and the thrust member moves to the other surface side of the flange portion. The shaft member can be stably rotated without providing the pressure bearing means.
[0053]
In the hydrodynamic bearing device according to the twelfth aspect of the present invention, the sleeve member is provided with a closing member facing the shaft portion of the shaft member, and the sleeve member together with the closing member surrounds the end portion of the shaft member. A space is defined, and this accommodation space is continuous with the gap of the sleeve fitting portion. The shaft member is provided with a channel that communicates the peripheral surface of the flange portion and the end surface of the shaft portion. Therefore, as described above, it is easy to seal the lubricating fluid, and the lubricating fluid is circulated through the channel through the thrust dynamic pressure bearing means and the radial dynamic pressure bearing means, and the thrust dynamic pressure bearing means and the radial dynamic pressure are circulated. The fluid pressure generated in the bearing means is adjusted, and the bubbles in the lubricating fluid are separated from the lubricating fluid and discharged to the outside.
[0054]
In the dynamic pressure fluid bearing device according to the thirteenth aspect of the present invention, since the elastic plug is attached to the lubricating fluid injection hole, leakage of the injected lubricating fluid is prevented.
[0055]
In the dynamic pressure fluid bearing device according to the fourteenth aspect of the present invention, since the injection hole used for injecting the lubricating fluid constitutes a part of the lubricating path for lubricating the lubricating fluid, the injection hole after the injection is not wasted at all. In addition to the function of adjusting the fluid pressure generated by the thrust dynamic pressure bearing means and the radial dynamic pressure bearing means, the configuration for the lubricating path and pressure adjustment function of the lubricating fluid is simplified.
[0056]
In the dynamic pressure fluid bearing device according to the fifteenth aspect of the present invention, since the shaft member is made of a magnetic material and a magnet piece for magnetically attracting the shaft member is provided, the thrust dynamic pressure can be obtained with a relatively simple configuration. The balance with the thrust force generated by the bearing means can be maintained.
[0057]
In the dynamic pressure fluid bearing device according to the sixteenth aspect of the present invention, the outer surface of the flange portion is provided with a taper seal structure in cooperation with the facing surface of the sleeve member facing the flange portion. Since it is also used as a reservoir, it can have a lubricating fluid sealing function and a reservoir function with a relatively simple structure of a taper seal structure. In addition, since the means for causing the shaft member to exert a force that balances the thrust support force of the thrust dynamic pressure bearing means is provided, the shaft member can be supported stably.
[0058]
In the motor of the nineteenth aspect of the present invention, the outer surface of the flange portion is provided with a taper seal structure in cooperation with the facing surface of the sleeve member facing the flange portion, and the portion of the taper seal structure is also used as a lubricating fluid reservoir. Therefore, the sealing function and the reservoir function of the lubricating fluid can be provided with a relatively simple configuration of a taper seal structure. Further, since the stator and the rotor magnet are disposed in a relative positional relationship so that a magnetic force that balances the thrust support force of the thrust dynamic pressure bearing means is applied to the shaft member, the rotor including the rotor magnet is stably supported. can do.
[0059]
In the dynamic pressure fluid bearing device of claim 17 and the motor of claim 20 of the present invention, since the circulation path for circulating the lubricating fluid is provided, the thrust dynamic pressure fluid bearing means and the radial motion are caused by the circulating action of the lubricating fluid. The fluid pressure generated by the pressure bearing means is adjusted, and the shaft member rotates stably.
[0060]
In the dynamic pressure fluid bearing device according to the seventeenth aspect of the present invention and the motor according to the twenty-first aspect, since the filter is disposed in the circulation path, impurities mixed therein are captured by the circulation of the lubricating fluid.
[0061]
In the motor according to the twenty-second aspect of the present invention, since the taper is provided over a relatively wide range of the surface of the sleeve member facing the flange portion of the shaft member, the taper seal having a sufficient taper space with this taper. It can be structured and can be a sufficient reservoir of lubricating fluid.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing a first embodiment of a motor provided with a hydrodynamic bearing according to the present invention.
2 is a partially enlarged cross-sectional view of a hydrodynamic bearing portion in the motor of FIG. 1. FIG.
FIG. 3 is a simplified explanatory diagram for explaining a method of injecting a lubricating fluid in the motor of FIG. 1;
FIG. 4 is a cross-sectional view of a main part showing a second embodiment of a motor provided with a hydrodynamic bearing according to the present invention.
5 is an enlarged partial perspective view showing a part of a shaft member in the motor of FIG. 4;
FIG. 6 is a sectional view showing another example of a hydrodynamic bearing according to the present invention.
[Explanation of symbols]
2,102 Base plate
10,104 rotor
11, 106 Dynamic pressure fluid bearing device
16 Rotor magnet
18 Stator
24, 112, 204 Shaft member
26, 108, 202 Sleeve member
28, 114, 210 Shaft
32, 116, 212 Flange
34 Injection hole
44 Cap member
52, 54, 122, 124, 214, 216 Radial dynamic pressure bearing means
56, 130, 218 Thrust dynamic pressure bearing means
60,122 taper
62, 123, 222 Lubricating fluid
70 Elastic plug
208 Magnet piece

Claims (22)

A shaft member having a shaft-like flange portion that protrudes radially outward from the shaft portion and rotates integrally with the shaft portion; and one end side in the axial direction is closed and the other end side is opened ; A sleeve member is fitted into the shaft portion with a predetermined interval therebetween, surrounds the flange portion, and is rotatable relative to the shaft member, and between the sleeve member and the shaft member. In a motor including a hydrodynamic bearing device including a lubricating fluid filled in a gap,
A radial dynamic pressure groove is provided on one or both of the shaft portion of the shaft member and the mutually opposing surfaces of the sleeve member,
A thrust dynamic pressure groove is provided on one or both of one surface of the flange portion of the shaft member and the first facing surface of the sleeve member facing the flange portion,
One or both of the other surface of the flange portion of the shaft member and the second facing surface of the sleeve member that opposes the radial direction in a relatively wide range from a position close to the shaft portion to the periphery of the flange portion. A taper is formed in which the interval narrows toward the outside,
The gap between the sleeve fitting portion of the sleeve member and the shaft member in the portion surrounding the flange portion forms a continuous space that is open to the outside only on the other end side , and is lubricated. The fluid is continuously filled from the gap of the sleeve fitting portion to the gap of the flange peripheral surface,
A stator is integrally provided on one of the shaft member and the sleeve member, and a rotor magnet is provided on the other so as to rotate integrally. The stator and the rotor magnet include the thrust dynamic pressure groove. A motor having a relative positional relationship such that a magnetic back pressure in a direction opposite to a thrust supporting force that balances with a thrust supporting force generated by the actuator acts on the shaft member. The said flange portion of the shaft portion of the shaft member provided opposite said sleeve member is closing member to face each other with a gap to the end of the sleeve member, said end portion of the shaft member with the closure member defining a housing space which surrounds the motor of claim 1, wherein the gap of said end portion, characterized in that the lubricating fluid continuous with a gap of the sleeve engaging portion is satisfied. The shaft member is provided with a pressure adjusting channel that communicates the peripheral surface of the flange portion and the end surface of the shaft portion, and the pressure adjusting channel is formed by a gap between the shaft member and the sleeve member. The motor according to claim 2, wherein a circulation path is formed. The shaft member is provided with a longitudinal hole that opens at the end of the shaft portion and extends in the longitudinal direction, and a communication hole that communicates the longitudinal hole with the peripheral surface of the flange portion. The motor according to claim 3. The motor according to claim 4, wherein the vertical hole is provided with a filter that captures impurities mixed in the lubricating fluid. Wherein the shaft member, the peripheral surface and the first surface of the flange portion of the flange portion, the flange portion pressure regulating channels for communicating the base portion near and the shaft portion is provided, the pressure adjustment channel wherein 3. The motor according to claim 2, wherein a circulation path of the lubricating fluid is formed by a gap between the flange portion and the sleeve member. The gap between the peripheral surface of the flange portion and the inner peripheral surface facing the flange portion peripheral surface of the sleeve member is set to a size that holds the lubricating fluid by capillary action. The motor in any one of 1-6. 2. A buffering restricting protrusion protruding outward in the radial direction is provided on a side portion of the peripheral surface of the flange portion on the side where the thrust dynamic pressure groove is provided. 8. The motor according to any one of 7. The flange portion surrounding portion of the sleeve member is fixed to the sleeve member main body, a sleeve member main body having a surface facing the circumferential surface and a surface of the flange portion on which the thrust dynamic pressure groove is provided, and the flange portion The motor according to claim 1, further comprising a lid portion facing a surface on which the taper is provided, wherein the lid portion is tapered. The annular groove near the base portion in the axial portion of the flange portion is formed, a motor according to claim 9, wherein溌油agent the annular groove, characterized in that it is coated. A shaft member having a shaft-like flange portion projecting radially outward from the shaft portion and rotating integrally with the shaft portion; one end portion in the axial direction is closed and the other end portion is opened ; A sleeve member that fits the shaft portion and the sleeve, surrounds the flange portion, and is rotatable relative to the shaft member, and a gap between the sleeve member and the shaft member with a predetermined interval therebetween. In a hydrodynamic bearing device comprising a filled lubricating fluid,
A radial dynamic pressure groove is provided on one or both of the shaft portion of the shaft member and the mutually facing surfaces of the sleeve member, and one surface of the flange portion of the shaft member and the first facing surface of the sleeve member facing the one surface. Thrust dynamic pressure groove is provided in one or both of the
One or both of the other surface of the flange portion of the shaft member and the second facing surface of the sleeve member that opposes the radial direction in a relatively wide range from a position close to the shaft portion to the periphery of the flange portion. A taper is formed in which the interval narrows toward the outside,
The gap between the sleeve fitting portion of the sleeve member and the shaft member in the portion surrounding the flange portion forms a continuous space that is open to the outside only on the other end side , and is lubricated. The fluid is continuously filled from the gap of the sleeve fitting portion to the gap of the peripheral surface of the flange,
The hydrodynamic bearing device according to claim 1, wherein a force in a direction opposite to a thrust support force that balances a thrust support force generated by the thrust dynamic pressure groove is applied to the shaft member. The closing member facing with a gap at an end portion opposite to the flange portion of the shaft portion of the shaft member is provided in the sleeve member, the sleeve member, said end portion of the shaft member with said closure member defining a housing space that surrounds the gap of the end portion has a lubricating fluid is filled in continuous with the gap between the sleeve engaging portion, and more the shaft member, the circumferential surface and the shaft portion of the flange portion of the end face and the pressure regulating channel communicating is provided a pressure adjustment channel of claim 11, wherein the forming the circulation path by the gap between the sleeve member and the shaft member Hydrodynamic fluid bearing device. The shaft member is formed with an injection hole for injecting a lubricating fluid penetrating from one end to the other end, and an elastic plug for preventing leakage of the injected lubricating fluid is formed in the injection hole. The hydrodynamic bearing device according to claim 12, which is mounted. The shaft member is provided with a communication hole that communicates the peripheral surface of the flange portion with a portion of the injection hole filled with the lubricating fluid, and a pressure adjusting channel is formed by the communication hole and the injection hole. The hydrodynamic bearing device according to claim 13. The shaft member is made of a magnetic material, and a magnet piece facing the shaft member is provided. The magnet piece has a force in a direction opposite to a thrust support force that balances a thrust support force generated by the thrust dynamic pressure groove. The hydrodynamic bearing device according to claim 11, wherein the hydrodynamic bearing device acts on a shaft member. A shaft member having a shaft portion and a disk-shaped flange portion that protrudes radially from the shaft portion and rotates integrally with the shaft portion, and one end side in the axial direction is closed and the other end side is opened, and the shaft member is between A sleeve member that fits the shaft portion and the sleeve at a predetermined interval, surrounds the flange portion, and is rotatable relative to the shaft member, and a space that is open to the outside only on the other end portion side . A hydrodynamic fluid bearing device comprising a lubricating fluid filled to a predetermined level in a continuous gap from the sleeve fitting portion to the flange surrounding portion between the sleeve member and the shaft member;
Radial dynamic pressure bearing means is provided in the sleeve fitting portion,
Thrust dynamic pressure bearing means is provided on the inner surface side of the flange portion and the portion of the facing surface of the sleeve member facing the flange portion,
The outer surface of the flange portion cooperates with the facing surface of the sleeve member facing the flange portion to form a taper seal structure that seals the lubricating fluid by surface tension, and is used as a lubricating fluid reservoir,
A hydrodynamic fluid bearing device comprising means for causing the shaft member to act on a force balanced with a thrust support force of the thrust dynamic pressure bearing means on the inner surface side of the flange portion. Wherein the axial portion and a lubricating fluid filled in the gap in the flange portion, the hydrodynamic bearing apparatus according to claim 16, wherein the forming the circulation path through the inside of the shaft member. 18. The hydrodynamic bearing device according to claim 17, wherein a filter for capturing impurities mixed in the lubricating fluid is provided in the circulation path. A shaft member having a shaft portion and a disk-shaped flange portion that protrudes radially from the shaft portion and rotates integrally with the shaft portion, and one end side in the axial direction is closed and the other end side is opened, and the shaft member is between A sleeve member that fits the shaft portion and the sleeve at a predetermined interval, surrounds the flange portion, and is rotatable relative to the shaft member, and a space that is open to the outside only on the other end portion side . A lubricating fluid filled to a predetermined level in a continuous gap from the sleeve fitting portion to the flange surrounding portion between the sleeve member and the shaft member; and a stator coupled to one of the shaft member and the sleeve member; A rotor magnet coupled to rotate integrally with the other of the shaft member and the sleeve member,
Radial dynamic pressure bearing means is provided in the sleeve fitting portion,
Thrust dynamic pressure bearing means is provided on the inner surface side of the flange portion and the portion of the facing surface of the sleeve member facing the flange portion,
The outer surface of the flange portion cooperates with the facing surface of the sleeve member facing the flange portion to form a taper seal structure that seals the lubricating fluid by surface tension, and is used as a lubricating fluid reservoir,
The stator and the rotor magnet are arranged in a relative positional relationship such that a magnetic force that balances a thrust support force of the thrust dynamic pressure bearing means on the inner surface side of the flange portion is applied to the shaft member. motor. 20. The motor according to claim 19, wherein a circulation path is formed through the shaft member for the lubricating fluid filled in the gap between the sleeve portion and the flange portion. 21. The motor according to claim 20, wherein a filter for capturing impurities mixed in the lubricating fluid is provided in the circulation path. The motor according to claim 19, wherein a taper is formed such that a distance between the sleeve member and the flange portion decreases in a radially outward direction over a relatively wide range of a surface facing the flange outer surface of the sleeve member.

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