JPH06178490A - Spindle motor - Google Patents

Abstract

PURPOSE:To make the attainment of reliable sealing possible while preventing also the leakage of a lubricant of a fluid dynamic pressure bearing provided inside, by fixing a cover member and a stationary member by a bonding agent and by sealing up a fit gap between the members. CONSTITUTION:A hub member 1 on which a recording disk is mounted and a stationary member (housing) 21 are provided. The hub member 1 is provided coaxially with a strut of which one end is an open end. The housing 21 is provided with a sleeve 3 which supports rotatably the strut inserted therethrough, and a dynamic pressure bearing using a lubricating fluid is provided by the strut and the sleeve 3. At the open end part of the strut, an annular member 4 engaging with the sleeve 3 and provided for regulating the position of the strut in the axial direction is fixed. On the open end side of the strut in the housing 21, a cover member 8 for covering the strut and the annular member 4 and closing up the sleeve 3 is fitted. The cover member 8 is fixed to the housing 21 by a bonding agent 9 and thereby sealed reliably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for rotating a recording disk such as an optical / magnetic disk, and
The present invention relates to a spindle motor equipped with a dynamic pressure bearing.

[0002]

2. Description of the Related Art A spindle motor used in a recording disk drive such as a magnetic disk or an optical disk is a hub member on which a recording disk is mounted, a shaft for rotationally supporting the hub member, a housing (or a bracket, etc.). ) Is provided. The hub member is rotationally driven relative to the housing. As the bearing means of the hub member, a fluid dynamic pressure bearing having high rotation accuracy and corresponding to the downsizing of the spindle motor is used in consideration of the recent tendency of downsizing and high capacity of the apparatus. Further, as a recording apparatus, strict accuracy is required for the height position regulation of the spindle motor in the direction of the rotation axis because of the head operation for accessing the recording disk. Therefore, in the spindle motor, a position regulating member that regulates the position in the rotation axis direction is provided on the shaft or the like, and is mounted so as to be engaged in the rotation axis direction. The position regulating member is covered with the cover member and accommodated in the housing. Usually, the cover member is fixed to the housing by screwing or the like.

[0003]

However, in the spindle motor having such a structure, since the fluid dynamic bearing is used as the bearing means, the lubricant, which is a fluid, leaks from a gap or the like in the mounting portion of the cover member. I had a chance to go out. Temporarily, there is also a method of fitting the cover member to the housing to increase the tolerance and press-fitting it, but it takes time and labor to process it, raises the production cost, and depending on the method of press-fitting, causes distortion in the housing, The fluid dynamic bearing may be affected. Thus, there has been a demand for some measure to be solved before mounting the cover member on the housing.

The present invention has been made in view of the above problems existing in the prior art, and the problem is that it is provided inside by a cover member that covers the position regulating member. It is possible to reliably seal the lubricant of the fluid dynamic bearing without bleeding and leaking.
Moreover, it is an object of the present invention to provide a highly reliable and highly productive spindle motor that can be easily mounted and mounted on a housing.

[0005]

In order to achieve the above object, the spindle motor of the present invention is provided by the following means. First of all, in the spindle motor by the first means,
A hub member to which a recording disk is mounted; and a stationary member, wherein the hub member is a spindle motor that is driven to rotate relative to the stationary member, and the hub member includes:
A pillar having one end as an open end is coaxially provided, and a sleeve is provided in the stationary member to rotatably support the pillar by inserting the pillar, and a dynamic pressure using a lubricating fluid is provided by the pillar and the sleeve. A bearing is provided, an annular member is fixed to an open end portion of the support column to engage with the sleeve, and regulates the position of the support column in an axial direction, and the stationary member has an open end side of the support column. A cover member for covering the support pillar and the annular member and closing the sleeve is attached to the stationary member, and the cover member is fixed to the stationary member with an adhesive.

In the spindle motor of the first means, an adhesive retaining groove for retaining an adhesive is provided at a corresponding portion of the cover member and / or the stationary member to which the cover member is fixed. Is desirable.

Next, the spindle motor according to the second means comprises a hub member on which a recording disk is mounted and a stationary member, and the hub member is a spindle motor driven to rotate relative to the stationary member. The stationary member is coaxially provided with a pillar having an open end, and the hub member is rotatably supported by inserting the pillar.
A sleeve is provided, and a dynamic pressure bearing using a lubricating fluid is provided by the strut and the sleeve, and an open end portion of the strut is engaged with the sleeve to regulate the position of the sleeve in the axial direction. For fixing the annular member,
A cover member for covering the support pillar and the annular member and closing the sleeve is attached to the hub member at the open end side of the support pillar, and the cover member is fixed to the hub member by an adhesive. It has been done.

Further, in the spindle motor according to the second means, an adhesive accumulating groove for accumulating an adhesive is provided at a corresponding portion of the cover member and / or the hub member to which the cover member is fixed. Is desirable.

[0009]

According to the spindle motor of the first means, the cover member is fixed to the stationary member with the adhesive.
It is possible to reliably fix the cover member and the stationary member with the adhesive and to reliably seal the fitting gap between the cover member and the stationary member. Further, the fitting between the cover member and the stationary member can be set relatively loosely because the adhesive is used, and the fitting can be done easily and the labor required for processing is not required. Since the adhesive accumulating groove is provided, the cover member acts as a wedge (wedge) for preventing the cover member from being separated from the stationary member, and the fixing of the cover member can be further strengthened.

According to the spindle motor of the second means, the cover member is fixed to the hub member with an adhesive. The cover member and the hub member can be reliably fixed by the adhesive, and the fitting gap between the cover member and the hub member can be reliably sealed. Further, the fitting between the cover member and the hub member can be set comparatively loosely because an adhesive is used, and the fitting can be done easily and the labor required for processing is not required. The provision of the adhesive accumulating groove acts as a wedge for preventing the cover member from being separated from the hub member, and further strengthens the fixing of the cover member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described with reference to FIGS. First of all,
7 to 7 show a first embodiment of a spindle motor for rotationally driving a magnetic disk, for example, and a sectional view thereof is shown.
(However, FIG. 3 shows a plan view. Similar parts are denoted by the same reference numerals.) In FIG. 1, reference numeral 1 denotes a reverse cup-shaped hub member, and a magnetic disk (not shown) is shown. It is mounted and rotated. The hub member 1 is made of an aluminum material. A magnetic disk (not shown) is fitted onto the outer peripheral surface 20 of the hub member 1, and a predetermined number of layers are sequentially stacked from the upper surface 14 of the flange 13 formed at the lower end of the hub member 1 to the upper side of the drawing. It The magnetic disk is pressed by a mounting member (not shown), and the rotation axis 4
It is screwed and fixed to a hole 11 formed coaxially with the screw 8. The hole 12 formed on the upper surface 41 of the hub member 1 is a hole for preventing rotation when the magnetic disk is mounted on the hub member 1. Reference numeral 2 denotes a shaft (support) coaxially fixed to the hub member 1, and an upper end portion 26 thereof is integrally fixed to the hub member 1 by press fitting or the like.

A rotor yoke 7 made of a ferromagnetic material such as an iron material is attached to the lower portion of the collar portion 13 of the hub member 1. The rotor yoke 7 has a ring shape, and is fixed to the lower surface 15 of the flange 13 and the lower side wall 16 in an externally fitted shape. Therefore, since the material of the hub member 1 is an aluminum material having a large coefficient of thermal expansion and the material of the rotor yoke 7 is an iron material having a smaller coefficient of thermal expansion, the degree of fixation is further improved even when the temperature of the spindle motor rises. Is increased. On the inner peripheral side of the rotor yoke 7, a rotor magnet 6 is annularly arranged and fixed. The upper end of the rotor yoke 7 is bent inward in the radial direction.
This is because the magnetic flux is not only attached to the flange portion 13 but also the leakage magnetic flux from the rotor magnet 6 is prevented from being transmitted to the magnetic disk side.

On the other hand, the housing 21 which is a stationary member,
It is composed of a flat supporting portion 29 and a cylindrical portion 22, and is integrally formed of, for example, an aluminum material. On the inner peripheral surface 23 of the cylindrical portion 22, a sleeve 3 which is also cylindrical and made of copper alloy or the like is fitted and fixed. As shown in the figure, the shaft 2 is inserted through the inner peripheral surface 30 of the sleeve 3. The small-diameter portion 24 at the lower end, which is the open end of the shaft 3, has an annular member 4 for restricting the position of the shaft 2 (and thus the hub member 1) in the axial direction 48.
And a cover member 8 covers the lower ends of the annular member 4 and the shaft 2. The cover member 8 is fitted and fixed in the peripheral wall 54 of the hole of the housing 21 so as to close the sleeve 3.

The armature 5 is mounted on the outer peripheral surface 28 of the cylindrical portion 22. The armature 5 is composed of a stator core 18 formed by laminating a predetermined number of electromagnetic steel plates, and an armature coil 19 wound around the stator core 18.
The magnetic pole portion of the armature 5 is the rotor magnet 6 of the hub member 1.
In contrast, they are arranged to face each other in the radial direction of the axis 48. In addition, the coil wire 1 drawn from the armature coil 19
7 is electrically connected to the printed circuit board 10 attached to the upper surface of the housing 21. This printed circuit board 10
Is led to the outside of the spindle motor.

In the spindle motor of the first embodiment, the hub member 1 is rotatably supported with respect to the housing 21,
A fluid dynamic bearing is used as this bearing means. In FIG. 2, a plurality of herringbone grooves 45 and 46, which are dynamic pressure grooves, are formed at upper and lower portions of the outer peripheral surface 25 of the shaft 2, whereby the shaft 2 supports the radial dynamic pressure bearing with respect to the sleeve 3. To be done. The gap between the inner peripheral surface 30 of the sleeve 3 and the outer peripheral surface 25 of the shaft 2 is filled with a lubricant as a lubricating fluid. In addition, the dynamic pressure groove is the shaft 2
It may be provided on the inner peripheral surface 30 side of the sleeve 3 as well as on the side. FIG. 3 is a plan view showing the upper and lower surfaces 31, 32 of the annular member 4. That is, FIG. 3A shows the upper surface 31 of the annular member 4.
3 (b) shows the lower surface 32 thereof. A plurality of spiral grooves 43, 44 which are dynamic pressure grooves are formed on these surfaces. The annular member 4 is integrally fixed to the lower end of the shaft 2. Therefore, as the shaft 2 rotates, the annular member 4 also rotates integrally. The upper surface 31 of the annular member 4 faces the recess 50 of the sleeve 3, while the lower surface 32 faces the upper end surface 49 of the cover member 8. The thrust dynamic pressure bearings are supported in the respective gaps. Similar to the radial dynamic pressure bearing portion, a similar lubricant is filled in these opposing gaps as a lubricating fluid. At the same time when this thrust dynamic pressure bearing is supported, the annular member 4
The position of the shaft 2 in the direction of the rotation axis 48 is restricted.

In FIGS. 1 and 2, the cover member 8 is
It is fitted into the peripheral wall 54 inside the cylindrical portion 22 of the housing 21, and is filled and fixed with an adhesive 9 for fixing the cover member 8. This part will be described in detail with reference to FIG. 7. FIG. 7 is an enlarged cross-sectional view of the peripheral portion of the cover member 8 of the spindle motor described above. In these figures, the cover member 8
The lower groove portion 41 and the taper portion 58 in the figure are filled with the adhesive agent 9, and the adhesive agent collecting groove 42 formed in the peripheral wall 54 of the housing 21 is also filled with the adhesive agent 9. By these, the adhesive force of the cover member 8 is increased with respect to the housing 21, and the cover member 8 is securely adhesively fixed. Cover member 8
An adhesive may be applied to the joining portion 40 between the peripheral wall 54 and the peripheral wall 54 so as to intervene, but by filling the adhesive 9 as shown in the figure, the adhesive force is increased and the sealing effect is large. That is, the groove portion 41 of the cover member 8 can be filled with a sufficient amount of the adhesive 9, and the adhesive area between the cover member 8 and the peripheral wall 54 is increased. The adhesive accumulating groove 42 formed in the peripheral wall 54 prevents the cover member 8 from separating from the housing 21 in the downward direction of the drawing.
Because of the above effect, the adhesive strength is increased more firmly. In addition, due to the temperature rise of the spindle motor itself and the like, the joint portion 40 due to the difference in thermal expansion between the housing 21 and the cover member 8 is generated.
Even if the distortion (acting in the opposite directions to each other in the vertical direction in the drawing) occurs, the taper portion 58 is set to an obtuse angle with respect to the line of action of the joining portion 40 (the vertical direction in the drawing). Therefore, the adhesive 9 does not easily peel off at the corresponding portion of the filled adhesive 9, that is, at the contact surface of the cover member 8 or the peripheral wall 54. Therefore, the sealing performance is maintained with high reliability.

Next, an assembly example of the spindle motor according to the first embodiment will be described with reference to FIGS. FIGS. 4 to 6 are the same as FIGS. 1 to 3 and FIG.
The same numbers are assigned to the same parts. First, as shown in FIG. 4, the shaft 2 is previously fitted into the hub member 1 to be integrally formed, and the rotor yoke 7 and the rotor magnet 6 are fixed to the collar portion 13 in an annular shape. On the other hand, on the housing 21 side, the printed circuit board 10 is attached to a predetermined portion, the sleeve 3 is fitted and fixed to the inner peripheral surface 23 of the cylindrical portion 22, and the outer peripheral surface 28 of the cylindrical portion 22 is provided with an electric machine. The child 5 is fixed to the outer fitting. Inner peripheral surface 30 of sleeve 3 and outer peripheral surface 2 of shaft 2
5 is coated with a required lubricant, and the assembly of the hub member 1 is inserted into the assembly of the housing 21 in the direction of the arrow in the drawing (downward in the drawing). Then Fig. 5
The state becomes as shown in. At this time, the step portion 38 inside the hub member 1 and the step portion 37 at the upper portion of the sleeve 3 come into contact with each other, but the gap space 5 generated at that time
3 is set to ensure a constant interval. That is, this means that when the sleeve 3 and the shaft 2 are inserted, the lubricant may slightly exude from the portion 61, but this causes a capillary phenomenon to the clearance space 53, and the direction toward the hub inner peripheral portion 51. This is to prevent bleeding into
Therefore, the gap space 53 is set to be larger than the wetting dimension formed by the surface tension of the lubricant.

Further, in FIG. 5, the annular member 4 is fitted into the small diameter portion 24 of the shaft 2. Then, in FIG. 6, the cover member 8 is fitted along the peripheral wall 54. At that time (see also the enlarged cross-sectional view of FIG. 7), since the cover member 8 is closed, a part of the air is left inside.
This air is released to the outside by the communication hole 33 provided in the cover member 8. Further, because the cover member 8 is closed, a part of the lubricant filled in the cover member 8 may overflow to the joint portion 40. To hold. In this way, after the cover member 8 is mounted, the adhesive 9 is filled into the groove 41 and fixed. At this time, a part of the adhesive 9 also flows into the communication hole 33, and the communication hole 33 is closed.

Next, FIGS. 8 and 9 show a second embodiment and a third embodiment of the spindle motor according to the present invention, and each is an enlarged sectional view showing the periphery of the cover member 8. . The same parts are assigned the same numbers as those already used. Only the points different from the first embodiment will be described below. Figure 8
In the second embodiment, the shape of the reservoir groove 56 in the peripheral wall 54 of the adhesive 9 is different. In this case, a taper portion similar to the taper portion 58 provided on the cover member 8 side is formed by the accumulation groove 56.
Is formed. Therefore, due to these taper shapes,
The angle becomes more obtuse with respect to the line of action of the joint 40, and the peeling of the adhesive 9 described above is prevented. Further, as another part, when the cover member 8 is fitted, a holding groove 57 that holds the lubricant that overflows is formed on the peripheral wall 5.
7 (cylindrical portion 22) side is different. Next, in the third embodiment shown in FIG. 9, a reservoir groove 60 for the adhesive 9 is formed.
Have different shapes. Thereby, the action of the wedge can be further increased with respect to the force acting so that the cover member 8 is detached in the downward direction of the drawing. Further, the holding groove 59 is formed on the peripheral wall 5.
4 and a part of the sleeve 3 are formed so as to have a gap therebetween. As a result, the storage capacity of the lubricant can be further increased, and the labor for processing for forming the groove is not required so much.

Next, FIG. 10 shows a spindle motor according to a fourth embodiment. While the spindle motors of the first to third embodiments already described are of the so-called shaft rotation type in which the shaft 2 and the hub member 1 rotate integrally, the spindle motor of the present embodiment is 72
Is integrally fixed to the housing 73, and the sleeve 74 is integrally fixed to the hub member 71, which is a so-called shaft fixing type. In this case as well, the hub member 71 and the sleeve 74 are similarly regulated in position in the direction of the rotation axis 90 via the annular member 79, and the cover member 75 causes the hub member 71 to move.
Fixed to. As can be easily understood from the contents described above, the cover member 75 is provided with the groove portion 77 and the reservoir groove 78, and is filled with the adhesive 76, whereby the cover member 75 and the hub member 71 are fixed to each other. These adhesives 7
The operation and effect of fixing by 6 are the same as those of the above-described embodiment except for the difference in the configuration of the spindle motor, and will be omitted. In FIG. 10, reference numeral 80 is an armature, and 81 is a rotor magnet that faces the armature 80 and is annularly arranged. Coil lead wire 9 pulled out from the armature 80
2 is led out of the spindle motor from the hole 93 of the housing 73. Further, the member 98 is the housing 7
3 is a holding member for holding and fixing the armature 80, and is made of an insulating resin material. This protects the insulation of the armature 80, and the armature 80
It is possible to effectively absorb electromagnetic vibrations and the like generated from the. In the spindle motor of the fourth embodiment, although not shown, a herringbone groove for generating radial dynamic pressure is formed on the outer peripheral surface 94 of the shaft 72 or the inner peripheral surface 95 of the sleeve 74, and the annular member is also used. Spiral grooves for generating thrust dynamic pressure are formed on the upper and lower end surfaces 96, 97 of 79. A lubricant is filled in the gap between these members.

The embodiment of the spindle motor according to the present invention has been described above in detail, but the present invention is not limited to this.
Modifications are free within the scope of the present invention. For example, it is needless to say that the shape and size of the groove filled with the adhesive or the reservoir groove, and the number of the dynamic pressure groove and the location of the fluid dynamic pressure bearing can be freely selected. Other materials etc. can be freely selected. In the spindle motor shown in FIG. 10 according to the fourth embodiment, the shaft 72 is located inside the cover member 75. The structure may be such that 72 projects through the cover member 75 and the spindle motor is supported and fixed at the end thereof. In this case, the spindle motor is supported at both ends of the axis 90, so that the rotation accuracy is further improved.

[0022]

Since the spindle motor of the present invention has the above-mentioned structure, it has the following effects. The cover member that covers the position regulating member does not exude even to the lubricant of the fluid dynamic bearing provided inside,
A highly reliable and highly productive spindle motor that can be reliably sealed and that can be easily mounted and mounted in a housing can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an entire spindle motor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a partial side surface appearing in FIG.

FIG. 3 is a plan view showing a part of the component shown in FIG.

FIG. 4 is a cross-sectional view for explaining an assembly sequence of the spindle motor of FIG.

5 is a cross-sectional view for explaining an assembling order of the spindle motor of FIG.

FIG. 6 is a cross-sectional view for explaining an assembling order of the spindle motor of FIG.

FIG. 7 is a cross-sectional view showing a part of the spindle motor of FIG. 1 in an enlarged manner.

FIG. 8 is a sectional view showing a part of a spindle motor according to a second embodiment of the present invention.

FIG. 9 is a sectional view showing a part of a spindle motor according to a third embodiment of the present invention.

FIG. 10 is a sectional view showing an entire spindle motor according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1,71 Hub member 2,72 Shaft 3,74 Sleeve 4,79 Annular member 8,75 Cover member

Claims (4)

[Claims] 1. A hub member on which a recording disk is mounted,
A stationary member, wherein the hub member is a spindle motor that is driven to rotate relative to the stationary member, and the hub member is coaxially provided with a pillar having an open end. Is provided with a sleeve that rotatably supports the support by inserting the support, a dynamic pressure bearing using a lubricating fluid is provided by the support and the sleeve, and the sleeve is provided at an open end of the support. An annular member for engaging and restricting the position of the support column in the axial direction is fixed, and the stationary member has an open end side that covers the support column and the annular member and closes the sleeve. A spindle motor, comprising: a cover member for mounting the cover member, the cover member being fixed to the stationary member with an adhesive. 2. The adhesive accumulating groove for accumulating the adhesive is provided in a corresponding portion of the cover member and / or the stationary member to which the cover member is fixed. The described spindle motor. 3. A hub member on which a recording disk is mounted,
A stationary member, wherein the hub member is a spindle motor that is driven to rotate relative to the stationary member, and the stationary member is coaxially provided with a pillar having an open end. Is provided with a sleeve through which the pillar is rotatably supported, a dynamic pressure bearing using a lubricating fluid is provided by the pillar and the sleeve, and the sleeve is provided at an open end of the pillar. An annular member is fixed for engaging with and restricting the position of the sleeve in the axial direction, and the hub member has an open end side that covers the pillar and the annular member, A spindle motor, wherein a cover member for closing is mounted, and the cover member is fixed to the hub member with an adhesive. 4. The adhesive accumulating groove for accumulating the adhesive is provided at a corresponding portion of the cover member and / or the hub member to which the cover member is fixed, the adhesive accumulating groove being provided. The described spindle motor.