JP2000283164A - Dynamic pressure bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent extrusion of adhesive by vertically dividing a fitting surface of bearing members of a bearing holding member into two parts, and forming a space enclosed between each bearing holding member and a bearing member as a reserving part of the adhesive. SOLUTION: Adhesive 4 is coated in an annular groove 1a of a radial bearing 1 or in the vicinity of the annular groove 1a, and is softly pressed from an upper end surface 2b side into a center hole 2e of a disk hub A2. The adhesive 4 is extruded and remained to a corner where a recessed surface 2c and an outer peripheral surface are brought into contact with each other, and is not extruded to a lower end surface 1c side. When a center hole 3a of a disk hub B3 is softly pressed in an outer periphery of the bearing 1, the inner diameter 3d of the lower recessed hole of the hub B3 is fitted at a sufficient clearance with an outer diameter of a small diameter cylindrical part 2a of the hub A2, the adhesive 4 is pushed down along an outer wall of the bearing 1 on a recessed surface 3c, and is housed in the space C, and is not extruded to an upper end surface 1b. The hub B3 is covered in the hub A2, and air closed between them is released to outside air by passing a fitting clearance between both members and a groove part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing device, and more particularly to a structure for fixing a bearing member and a bearing holding member.

[0002]

2. Description of the Related Art Conventionally, for example, various dynamic pressure bearing devices have been employed for a spindle motor for an HDD. JP-A-6
In the spindle motor disclosed in FIG. 1 of Japanese Patent No. 103691, a thick cylindrical rotary sleeve 34 is fitted and fixed to a central hole of the rotor hub 28 and integrated, and the rotary sleeve 34 is fixed to the fixed support 14 side. It is fitted around the sleeve 15 and rotates about the fixed support 14 by electromagnetic interaction between the magnetic field generated by the coil 26 and the rotor magnet 32. The rotating sleeve 34 has a dynamic pressure generating groove formed on the inner peripheral surface thereof, and serves as a dynamic pressure radial bearing filled with lubricating oil. Also, Japanese Patent Application Laid-Open No. 9-217735
In the motor disclosed in FIG. 1 of the publication, a center fixed shaft 22 is supported by a radial bearing 25 and a disk hub 24 is provided.
A radial bearing 25 is fitted and fixed in the center hole of the disk hub 24. The electromagnetic interaction between the magnetic field generated by the coil 33 and the drive magnet 34 causes the disk hub 24 to
Rotate around. Dynamic pressure generating grooves 22b, 22b are formed on the outer peripheral surface of the center fixed shaft 22.

Further, in the motor disclosed in FIG. 2 of Japanese Patent Laid-Open No. 10-96421, a journal unit is fitted and fixed in a center hole of a hub 14 constituting a rotor, and the journal unit is mounted on the inner and outer circumferences. A cylindrical inner yoke 24 and an outer yoke 21 are provided, and a pair of upper and lower dynamic pressure bearings, bearing support portions 22a and 22b, are integrally connected and fixed in advance with a cylindrical magnet member 23 interposed therebetween. The fixed shaft 11 is supported via a magnetic fluid. The hub 14 rotates about the fixed shaft 11 by the interaction between the stator coil 15 and the magnet 16. As a structure common to these bearing devices, the outer periphery of a cylindrical radial bearing that supports a fixed shaft is fitted and fixed to the inner periphery of a disk hub.

On the other hand, the motor disclosed in FIG. 1 of Japanese Patent Application Laid-Open No. Hei 8-210364 has a pair of dynamic pressure radial sliding bearings 24 on the inner peripheral portion of a cylindrical bearing holder 22 erected at the center of the frame 10. The rotating shaft 31 is rotatably supported by the bearings 24, 24. The lower end of the rotating shaft 31 is a dynamic thrust bearing 2
6, and a hub 37 constituting the rotor set 30 is fixed to the upper end, and rotates integrally with the rotating shaft 31 by the interaction between the stator core 21 and the driving magnet 36.

Since these dynamic pressure bearing devices are used for driving a storage medium, it is a particularly important quality that the disk hub holding the storage medium does not become eccentric with rotation. Therefore, a groove for generating dynamic pressure is formed on at least one of the opposed surfaces of the radial bearing member and the rotating shaft or the fixed shaft supported by the radial bearing member, and a lubricant is held between the opposed surfaces, and with the rotation, The opposing surfaces are not mutually displaced in the radial direction by the generated dynamic pressure of the lubricant. Further, in fixing the bearing member to a member having a cylindrical inner surface (hereinafter, referred to as a bearing holding member), the eccentricity does not occur and the size of the entire storage device needs to be reduced. Therefore, a fixing structure that does not require a large volume is desirable.

The structure for fixing the bearing member of such a conventional hydrodynamic bearing device will be further described with reference to the drawings. FIG. 5 is a sectional view showing a main part of a conventional bearing device.

In FIG. 5, reference numeral 11 denotes a radial bearing as a bearing member for supporting a rotating shaft or a fixed shaft (not shown) having a dynamic pressure generating groove formed in a center hole, and 12 denotes a radial bearing 11 in its center hole 12a. This is a disk hub for holding a storage medium as a bearing holding member with its outer periphery fitted and fixed. In particular, the outer peripheral side of the disk hub 12 is simplified and only the main part is shown. Since the radial bearing 11 and the disk hub 12 are fitted by light press-fitting so as not to be eccentric, and the apparatus is required to be downsized,
An adhesive fixing structure that does not require a large volume is employed. Since there is no gap in the fitting portion, a plurality of annular grooves 11 a for holding the adhesive are formed on the outer periphery of the radial bearing 11. The end face 11 b of the radial bearing 11 is located at a position retracted inward from the end face 12 b of the disk hub 12. A thrust bearing or the like is provided in a space outside the end face 11b surrounded by a shaft (not shown) supported by the radial bearing 11 and the disk hub 12.

Next, a method for assembling the above-described dynamic bearing device will be described with reference to the drawings. 6 and 7 are sectional views showing a method of assembling the conventional hydrodynamic bearing device shown in FIG. 8 and 9 are cross-sectional views showing a method of assembling another conventional bearing device.

In FIG. 6, reference numeral 15 denotes an anaerobic or thermosetting adhesive, which is preliminarily applied to the vicinity of the annular groove 11a of the radial bearing 11. This radial bearing 1
1 is inserted into the center hole 12a in the direction of the arrow from one end face 12b of the disk hub 12. Since the adhesive 15 is applied so as to protrude from the annular groove 11a in the radial direction, when the radial bearing 11 is inserted, it is blocked at the end face 12b of the disk hub 12, and after the insertion is completed, as shown in FIG. From the top to the upper surface of the end face 11b.

In FIG. 8, reference numeral 21 denotes a bearing member,
Reference numeral 22 denotes a disk hub of the bearing holding member, and a plurality of annular grooves 22b for holding the adhesive 15 are provided in the center hole 22a of the disk hub 22. The radial bearing 21 is inserted in the direction of the arrow into the center hole 22a of the disk hub 22 in which the adhesive 15 has been applied to the annular groove 22b in advance. In this case, after the insertion is completed, FIG.
As shown in the figure, the adhesive 15 protrudes and remains on the end face 21b of the radial bearing 21 on the side opposite to the side where the radial bearing 21 is inserted. The protruding adhesive 15 is wiped before curing so as not to interfere with a member to be incorporated later.

[0011]

However, the end faces 11b or 21b of the radial bearings 11 or 21 are both set to the end faces 12b or 22b of the disc hub 12 or 22.
If it is more retracted, this extra adhesive 15
Each of the radial bearing end surfaces 11b and 21b and the inner peripheral surfaces of the disk hubs 12 and 22 will remain at the concave corners, so it is not easy to remove them and it takes time and cannot be completely wiped off completely. The adhesive 15 remaining on the end face 11b or 21b of the radial bearing 11 or 21 without wiping may cause interference with the thrust bearing, and the inner circumference of the radial bearing 11 or 21 and a rotating shaft or fixed shaft (not shown). The lubricating agent intervenes between the end face 12b and the side face 22b.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and prevent the adhesive from sticking out when the bearing member and the bearing holding member of the dynamic pressure bearing device are bonded. Even if the sticking out occurs, it is extremely easy and reliable. Another object of the present invention is to provide a structure of a bearing device capable of wiping off excess adhesive.

[0013]

According to a first aspect of the present invention, an outer periphery of a bearing member for supporting a rotating shaft or a fixed shaft is fitted into a center hole of a bearing holding member. In the fixed hydrodynamic bearing device, the bearing holding member is divided so that a fitting surface of the bearing holding member with the bearing member is vertically divided into two, and the divided bearing holding member is A space is formed so as to be surrounded by each and the bearing member, and the space is a reservoir for an adhesive for joining the bearing member and the bearing holding member.

According to a second aspect of the present invention, in the first aspect of the present invention, the adhesive reservoir is provided with a ventilation path for communicating the adhesive reservoir with the outside air. I do.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydrodynamic bearing device according to an embodiment of the present invention will be described below in detail with reference to the drawings. FIG.
FIG. 1 is a sectional view of a main part showing a configuration of a dynamic pressure bearing device of the present invention. FIG. 2 is a perspective view showing one of the bearing holding members in FIG. 1 in detail.

In FIG. 1, reference numeral 1 denotes a radial bearing for supporting a rotating shaft or a fixed shaft (not shown) formed with a dynamic pressure generating groove. A plurality of annular grooves 1a for holding an adhesive are provided on the outer periphery of the radial bearing 1. Are formed. The holding member of the radial bearing 1 is divided so that a fitting surface with the radial bearing 1 is vertically divided into two, and 2 is a cylindrical disk hub A having an outer step as one of the divided bearing holding members. It is. As shown in FIG. 2, there is a sinking surface 2c on the inner peripheral side of the end surface 2b of the small diameter cylindrical portion 2a on the step 2g of the disk hub A2, and the outer periphery of the small diameter cylindrical portion 2a has an axial direction. 3d grooves 2d are formed. The bottom surface of the groove 2d is connected to the sinking surface 2c by cutting out the end surface 2b. As shown in FIG. 1, a radial bearing 1 is lightly press-fitted and bonded to a center hole 2e of the disk hub A2. The lower end surface 1c of the radial bearing 1 is located at a position retracted from the lower end surface 2f of the disk hub A2.

Reference numeral 3 denotes an inner stepped cylindrical disk hub B which is the other of the divided bearing holding members.
The radial bearing 1 is lightly press-fitted and bonded to a.
The lower end surface 3b of the disk hub B3 is in contact with the step 2g of the disk hub A2. The inner peripheral side of the lower end surface 3b is the sinking surface 3.
c, and the sinking surface 3c is in contact with the upper end surface 2b of the disk hub A2. The space surrounded by the sinking surfaces 3c and 2c is a reservoir for the adhesive. The disk hub A2 and the disk hub B3 are combined via the radial bearing 1 to form one disk hub. That is, the disk hub is divided so that the joint surface of the disk hub with the radial bearing is divided into two parts vertically, and is surrounded by one of the divided disk hubs A2, the other disk hub B3, and the radial bearing 1. The space S is formed as described above, and this space S is used as a reservoir for the adhesive for joining the radial bearing 1 and the disk hub. And the space S is the disk hub A2, B
3 and a groove 2d serve as an air passage and communicate with the outside air.

Next, a method of assembling the hydrodynamic bearing device will be described with reference to the drawings. 3 and 4 are cross-sectional views for explaining a method of assembling the bearing device.

In FIG. 3, the same reference numerals are used for the same components as those in FIGS. 1 and 2, and the description is omitted. Here, reference numeral 4 denotes an anaerobic or thermosetting adhesive for bonding and fixing the bearing member and the bearing holding member. As shown in FIG. 3, an adhesive 4 is applied in or near the annular groove 1a provided in the radial bearing 1. The radial bearing 1 is inserted into the center hole 2e of the disk hub A2 in the direction of the arrow from the upper end surface 2b side. This fitting is light press-fitting as before. Therefore, when the radial bearing 1 is pressed into the disk hub A2, the adhesive 4 protrudes and remains at the corner where the sinking surface 2c and the outer peripheral surface of the radial bearing 1 come into contact as shown in FIG. However, the adhesive 4 does not protrude to the lower end surface 1c side of the radial bearing 1.

Next, the disk hub B3 is combined with the radial bearing 1 combined with the disk hub A2. Here, an adhesive 4 is applied to the radial bearing 1 in advance, and the center hole 3a of the disc hub B3 is fitted and pressed into the outer periphery of the radial bearing 1 supported by an assembling jig or the like. This fitting is also light press-fitting.

At this time, the inner diameter 3d of the sink hole below the disk hub B3 is fitted with a sufficient clearance with the outer diameter of the small-diameter cylindrical portion 2a of the disk hub A2. The adhesive 4 applied to the outer periphery of the radial bearing 1
3 is pushed down along the outer wall of the radial bearing 1 by the sinking surface 3c, and fits in the space S. The adhesive 4 does not protrude from the upper end surface 1b of the radial bearing 1. The air trapped by the disc hub B3 over the disc hub A2 and trapped therebetween escapes to the outside air via the fitting gap between the two members and the groove 2d. The space S serves as a reservoir for the adhesive. If the volume of the reservoir is set to be sufficiently large with respect to the amount of the adhesive 4 to be applied, the adhesive 4 is pressed into the space S by the press-fitting of the disk hub B3. Stay within. Even if it protrudes from the space, it does not protrude to the outside because the groove 2d also serves as a reservoir for the extra adhesive 4. Even if it comes to the outer peripheral portion, it is easy to completely wipe it off because it is the outer peripheral portion of the disk hub.

In the above embodiment, the adhesive reservoir is provided on one of the divided disk hubs. However, the adhesive reservoir may be provided on the other disk hub, or may be provided over both. It is. Further, the air passage communicating the adhesive reservoir with the outside air is provided as a groove in one of the disk hubs, but may be provided as a hole penetrating in the other disk hub in the radial direction. By providing a gap in the fitting portion between the two disk hubs, these ventilation paths can be omitted. The annular groove serving as an adhesive holding portion for bonding the radial bearing and the disk hub may be provided with, for example, an axial groove connecting a plurality of annular grooves and opening the end surface. Of course, grooves of various shapes can be formed instead of the annular grooves. Further, the structure of the hydrodynamic bearing device of the present invention is not limited to a motor for an HDD, but is versatile.

[0023]

According to the present invention, a bearing holding member of a dynamic pressure bearing device in which the outer periphery of a bearing member for supporting a rotating shaft or a fixed shaft is fitted and fixed to a center hole of the bearing holding member is joined to the bearing member. The surface was divided so that the surface was divided into upper and lower parts, and a space was formed so as to be surrounded by the divided bearing holding members and the rotating shaft or the fixed shaft. It was possible to prevent the adhesive from sticking out to the end face of the bearing member and remaining when bonding to the bearing holding member.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing a dynamic bearing device of the present invention.

FIG. 2 is a perspective view showing one bearing holding member of the dynamic pressure bearing device of the present invention.

FIG. 3 is a sectional view showing an assembling method of the dynamic pressure bearing device of the present invention.

FIG. 4 is a sectional view showing a method of assembling the dynamic pressure bearing device of the present invention.

FIG. 5 is a sectional view of a main part showing a conventional hydrodynamic bearing device.

FIG. 6 is a cross-sectional view illustrating a method of assembling a conventional hydrodynamic bearing device.

FIG. 7 is a sectional view showing a method of assembling a conventional bearing device.

FIG. 8 is a cross-sectional view illustrating a method of assembling another conventional bearing device.

FIG. 9 is a cross-sectional view illustrating an assembling method of another conventional bearing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radial bearing 2 Disk hub A 3 Disk hub B 4 Adhesive

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takashi Shimada 4107, Miyoshida, Miyoshida-cho, Kitasaku-gun, Nagano Prefecture 5107 Inside Simeo Precision Co., Ltd. Within Simeo Precision Co., Ltd. (72) Isao Mizuma Inventor 4107 Miyoshida, Miyoda-cho, Kitasaku-gun, Nagano Pref. 5 F-term within Simeo Precision Co., Ltd. (reference)

Claims (2)

[Claims] In a hydrodynamic bearing device in which an outer periphery of a bearing member supporting a rotating shaft or a fixed shaft is fitted and fixed in a center hole of a bearing holding member, a fitting surface of the bearing holding member with the bearing member. The bearing holding member is divided so as to be vertically divided into two, and a space is formed so as to be surrounded by each of the divided bearing holding members and the bearing member. A dynamic pressure bearing device comprising an adhesive reservoir for joining the bearing holding member. 2. An air passage for communicating between the adhesive reservoir and the outside air is provided in the adhesive reservoir.
The hydrodynamic bearing device according to the above.