JP3177024B2 - Spindle motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor used for rotating a recording disk such as an optical or magnetic disk.

[0002]

2. Description of the Related Art A conventional spindle motor used in a recording disk drive such as a magnetic disk or an optical disk will be described with reference to FIG. FIG. 5 is a sectional view showing the entire spindle motor. In FIG. 5, c
Is a hub member on which a recording disk (hereinafter referred to as a disk) is mounted, a is a fixed support, b is a bracket, e and f are bearing members, d is an armature, g is a rotor magnet, and h is a disk. The bracket b, which is a stationary member, is attached and fixed to the fixed frame A of the disk drive device using k as an attachment reference plane, although not shown. A pair of bearings e and f are fitted into the fixed support a fixed integrally with the bracket b, and the hub member c is rotatably supported via the bearings e and f. A required number of disks h are mounted and fixed to the hub member c. A rotor magnet g is annularly disposed inside the lower end of the hub member c, and an armature d is fixed to the center of the bracket b so as to face the rotor magnet g. Therefore, when the required power is supplied to the armature d, the hub member c is driven to rotate relative to the bracket b by the electromagnetic action of the armature d and the rotor magnet g. In order to prevent unclean air inside the spindle motor from flowing out of the spindle motor (that is, inside the disk drive), a labyrinth seal t is provided by a seal member s and a bracket b and a hub member c. I have. By the way, the distance L between the mounting surface j of the disk h of the hub member c and the mounting reference surface k of the bracket b is such that the bearing f is sandwiched between the protrusion m of the hub member c and the protrusion n of the bracket b. Is set. That is, the protrusion m of the hub member c presses the upper end of the outer ring q of the bearing f, and the protrusion n of the bracket b receives the lower end of the inner ring p of the bearing f.

[0003]

However, the distance L set by such a structure is affected by the tolerance of the thickness B of the bearing f. For this reason, the distance between the disk h mounted on the hub member c and the reading / writing head of the disk device (not shown) facing the disk h varies for each spindle motor, and the reading / writing of the disk device varies. There is a problem that the writing operation becomes inaccurate. Incidentally, as an example of this problem, the tolerance of the thickness dimension B of the bearing f is about 0.04 mm, and the tolerance of the interval L is about 0.06 mm. Therefore, the interval L
Is about 0.02, the difference between both tolerances.
mm, the machining accuracy and the assembly accuracy of the bracket b and the hub member c must be kept within this range. Therefore, conventionally, the distance L is set to be relatively long, and after assembling the spindle motor, the mounting surface j of the disk h of the hub member c is ground and set within a predetermined tolerance. However, there was a problem that it took. Further, since the sealing performance of the spindle motor is ensured, it is necessary to make the gap between the hub member c and the bracket b opposed thereto small in order to enhance the performance of the labyrinth seal t. Therefore, there is a problem that it takes more time and effort.

The present invention has been made in view of the above-mentioned problems in the prior art, and it is an object of the present invention that the machining accuracy and the assembly accuracy of the hub member and the bracket are so required. An object of the present invention is to provide a highly reliable spindle motor capable of reliably performing reading and writing operations of a disk device and achieving high sealing performance without contaminating a disk chamber.

[0005]

In order to solve the above problems, a spindle motor according to the present invention comprises a stationary member, a hub member on which a recording disk is mounted, and a hub member interposed between the stationary member and the hub member. A bearing member provided, wherein the hub member is rotatably supported with respect to the stationary member; and a side end of an inner ring portion of the bearing member includes A first protruding portion formed integrally is abutted, and a side end of the outer ring portion of the bearing member on the same side as the inner ring portion is connected to the hub member.
The second protruding portion formed integrally is abutted.

The first protruding portion of the stationary member and the second protruding portion of the hub member are opposed to each other in a radial direction with respect to a rotation axis with a small gap over the entire circumference. It is desirable to provide a labyrinth seal.

[0007]

According to the spindle motor of the present invention, the side end of the inner ring portion of the bearing member is connected to the first protrusion of the stationary member, while the outer end of the outer ring portion of the bearing member is still connected to the second protrusion of the hub member. The side ends abut. Moreover, these inner and outer ring portions are in contact with the same side end. Therefore, the hub member is attached to the stationary member without sandwiching the bearing member, and is supported by rotation. For this reason, the hub member is attached to the stationary member without being affected by the thickness tolerance of the bearing member.

Further, the first and second projecting portions are
The labyrinth seal is formed because the labyrinth seal is formed in such a manner as to be opposed to the rotation axis in the radial direction with a small gap over the entire circumference. For this reason, it is substantially prevented that the unclean air from the bearing member flows out of the spindle motor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described with reference to FIGS. FIG. 1 is a first embodiment of a spindle motor mounted on, for example, a magnetic disk drive, and is a sectional view showing the entirety thereof. It should be noted that the spindle motor of the present invention can be used for driving various other recording media or for other uses. In FIG. 1, the member 14 is a bracket. The bracket 14 has a shallow dish shape and has an annular groove 16 that opens upward in FIG. 1, and a protrusion 20 is provided outside the upper end of the outer peripheral wall 18 in the annular groove 16. The lower end surface 29 of the overhang portion 20 is joined and fixed to the mounting surface of the fixed frame A of the magnetic disk drive. The lower end surface 29 is also a reference mounting surface for the fixed frame A.

At the center inside the inner peripheral wall 22 of the annular groove portion 16, a fixed column 10 is fitted and fixed in the direction of the rotation axis. The member 26 is a circuit board provided at the bottom of the annular groove 16, and the member 28 is a magnetic pole position detecting element.
The member 30 is a flexible circuit board having one end connected to the circuit board 26, and through a through hole 32 provided in the bottom plate of the bracket 14, on the lower surface side of the bracket 14, that is, outside the spindle motor (the outside of the magnetic disk drive device). (To the fixed frame A side). The member 34 is a filler such as an adhesive that seals the through hole 32, and thereby seals the inside and the outside of the spindle motor.

A cylindrical portion 36 having a reduced diameter is formed above the inner peripheral wall 22 in FIG. An armature 47 is fixed to the outer peripheral side of the tubular portion 36. Armature 47 is
A stator core 46 is formed by laminating a required number of electromagnetic steel sheets, and an armature coil 44 wound around the stator core 46. A coil lead wire (not shown) drawn from the armature coil 44 is electrically connected to the circuit board 26.

The member 48 is a substantially cylindrical aluminum hub member. The outer side of the outer peripheral wall 50 of the hub member 48 in FIG.
2 protrudes, and a magnetic disk (not shown) is provided above the disk support portion 52 on the outer peripheral portion of the outer peripheral wall portion 50.
Are externally fitted and fixed. That is, the magnetic disk is received and held by the mounting surface 25 of the disk support 52. Accordingly, the height dimension of the mounting surface 25 of the magnetic disk with respect to the mounting reference surface 29 of the bracket 14 is the distance L in FIG.
The dimensional tolerance of the interval L is important in performing the reading / writing operation of the magnetic disk drive.

The outer peripheral surface of the disk support 52 and the inner peripheral surface of the outer peripheral wall 18 in the annular groove 16 of the bracket 14
A labyrinth seal 33 is formed facing the rotation axis in the radial direction with a slight gap therebetween. The upper inner peripheral portion of the hub member 48 is formed in the small-diameter inner peripheral portion 54, and the lower portion of the hub member 48 below the small-diameter inner peripheral portion 54 is
The diameter is increased to form a large-diameter inner peripheral portion 56. A substantially cylindrical rotor yoke 58 whose upper portion is slightly bent inward is fixed to the large-diameter inner peripheral portion 56, and a cylindrical rotor magnet 60 is fitted and fixed inside the rotor yoke 58. The hub member 48, the rotor yoke 58, and the rotor magnet 60 mainly constitute a rotating unit.

A hub member 48 is provided on the outer peripheral side of the fixed column 10 above the stator core 46 via ball bearings 62 and 64 (an example of a rolling bearing) which are disposed in the vertical position in FIG. Are rotatably supported at the small diameter inner peripheral portion 54. The outer ring portions 62o, 64o of the upper and lower ball bearings 62, 64 are connected to the small diameter inner peripheral portion 54 of the hub member 48.
The inner ring portions 62i and 64i are bonded and fixed to the outer peripheral portion of the fixed support column 10. Upper and lower outer ring 62
An annular spacer 66 is interposed between o and 64o. In particular, the inner ring portion 64i in the lower ball bearing 64
Is in contact with a first protrusion 31 formed integrally with the upper end of the tubular portion 36. The lower end of the outer ring portion 64o is integrated with the lower end of the small-diameter inner peripheral portion 54 of the hub member 48.
It is in contact with the second protrusion 72 formed. The second protruding portion 72 is formed to extend inward in the radial direction with respect to the rotation axis of the small-diameter inner peripheral portion 54, and is formed in an annular shape.
In addition, the first protrusion 31 and the second protrusion 72 are opposed to each other with a minute gap 38 extending over the entire circumference in the radial direction with respect to the rotation axis, and form a labyrinth seal. .

The member 74 is a magnetic fluid seal. Two annular pole pieces 76 constituting the magnetic fluid seal 74
The annular permanent magnet 78 sandwiched between them is fixed to a slightly enlarged portion of the upper end of the small-diameter inner peripheral portion 54 of the hub member 48. A magnetic fluid 80 is held and fixed between the inner peripheral portion of the annular pole piece 76 and the outer peripheral surface of the fixed column 10. The member 82 is an annular flat protective cap fixed to the hub member 48 above the magnetic fluid seal 74. The protective cap 82 is attached for the purpose of protecting a hand or a foreign substance from the outside of the spindle motor from being easily touched or mixed with the inside of the spindle motor, particularly the magnetic fluid seal 74. The member 84 is a screw hole provided in the hub member 48 for screwing a clamp member (not shown) for fixing the magnetic disk. For example, six screw holes 84 are provided on the hub member 48 in a rotationally symmetric manner about the rotation axis. The portion of the screw hole 84 that opens into the inside of the spindle motor is sealed by a seal member 88. This is to prevent metal powder and the like from scattering outside through the inside of the spindle motor and attaching to the magnetic disk surface. In addition,
The screw hole 84 is formed through the hub member 4.
This is because, when the surface treatment is performed on the surface of the screw hole 8, the treatment liquid penetrates to every corner of the screw hole 84 and does not leave an untreated portion.

In this spindle motor, the ball bearing 6 for rotatably supporting the hub member 48 with respect to the fixed column 10 is provided.
2, 64, the lower end portion of the inner and outer ring portions 64i, 64o of the lower ball bearing 64 is the first projecting portion 31,
It is provided in contact with the second protruding portion 72. for that reason,
The hub member 4 with respect to the mounting reference surface 29 of the bracket 14
The height of the disk mounting surface 8, that is, the interval L, is the ball bearing 64.
Is set irrespective of the tolerance of the thickness dimension B. Therefore, since the interval L is not affected by the tolerance of the thickness B of the ball bearing 64, the allowable tolerance of the dimension of the interval L is not narrowed unlike the related art. For this reason, the required processing accuracy and assembly accuracy of the hub member 48 and the bracket 14 are not required more strictly than necessary, and the dimensional accuracy of the interval L can be easily increased. Further, if the dimensional accuracy of the interval L can be improved, the interval between the magnetic disk mounted on the hub member 48 and the magnetic head facing the magnetic disk is set with high accuracy, so that the reading / writing operation is performed It is executed reliably.

Further, the first protrusion 31 and the second protrusion 72 are opposed to each other in the radial direction with respect to the rotation axis with a minute gap 38 extending over the entire circumference, so that a labyrinth seal is formed. Have been. Since the minute gap portion 38 is located in the radial direction between the inner race portion 64i and the outer race portion 64o of the lower ball bearing 64 (slightly near the center of the rotation axis in FIG. 1), it is located inside the inner race portion 64i and the outer race portion 64o. In addition to effectively preventing the lubricant flowing along from leaking from the minute gap portion 38, the lubricant of the upper and lower ball bearings 62 and 64 causes the lubricant between the ball bearings 62 and 64 and the stator core 46 to pass through. By this, it is possible to prevent the splatter from being scattered outside the spindle motor. In particular, in this spindle motor, the hub member 48 rotates, and with this rotation, a centrifugal force acts radially outward on the second protrusion 72 provided integrally with the hub member 48. Therefore, even if the lubricant of the lower ball bearing 64 tries to flow downward, it can be retained inside the minute gap 38 (upper side in FIG. 1), and the minute gap 38
Can be reliably prevented from leaking. Further, since the outer peripheral surface of the disk support portion 52 and the inner peripheral surface of the outer peripheral wall 18 in the annular groove portion 16 of the bracket 14 are opposed to each other in the radial direction with a slight gap therebetween, the inside of the spindle motor can be provided with a lubricant or the like. The effect of the labyrinth seal prevents the unclean air containing fine particles and the like from leaking out of the spindle motor through the gap. On the other hand, the upper side of the upper and lower ball bearings 62 and 64 is sealed by a magnetic fluid seal 74.

In the spindle motor of the present invention, the upper and lower ball bearings 62 and 64 can be separated by interposing the spacer 66 on the small diameter inner peripheral portion 54 of the hub member 48. Therefore, unlike the conventional spindle motor shown in FIG. 5, it does not have the protrusion m. For this reason, processing and assembly from one direction, that is, from the upper direction to the lower direction in FIG. 1 become possible, and labor saving and automation can be achieved.

FIGS. 2 to 4 show a second embodiment of the spindle motor according to the present invention. FIG. 2 is a sectional view of a spindle motor for rotating and driving a magnetic disk, as in the first embodiment shown in FIG. FIG. 3 is a plan view of the spindle motor of FIG. 2 viewed from above in the figure to below. In FIG. 3, the section taken along the line XY is shown in FIG.
It appears as FIG. 4 will be described later.
9 shows a fixing member 41 for holding and fixing the flexible circuit board 39 shown in FIG. 2 to 4 will be described below. In the spindle motor according to the second embodiment, parts similar to those of the spindle motor according to the first embodiment described above are omitted, and only different parts will be described.

In FIG. 2, the bracket 15 as a stationary member is formed integrally with the fixed support 11. Therefore, since the bracket 15 is integrally formed including the fixed support 11, the number of processing steps and the number of parts can be reduced. A first protruding portion 21 is integrally formed in a stepwise manner at the root of the fixed support 11 in the bracket 15. The lower end of the inner ring portion of the ball bearing 53 is provided in contact with the step of the first protrusion 21. The second protrusion 23 is integrally formed at the lower end of the small-diameter inner peripheral portion 87 of the hub member 47 in which the ball bearing 53 is interposed, and the lower end of the outer ring portion of the ball bearing 53 is in contact with the second protrusion 23. It is provided. Therefore, in the present spindle motor, similarly to the first embodiment, the height of the mounting surface of the hub member 47 in the disk support portion 35 with respect to the mounting reference surface 37 of the bracket 15, that is, the interval L is the thickness of the ball bearing 53. It is not affected by B tolerance. Moreover, the first collision-like portion 21 a
The two crash-shaped portion 23, a labyrinth seal 99 is formed.

The magnetic fluid seal 71 provided above the spindle motor has the same configuration as the magnetic fluid seal 78 shown in FIG. 1, except that a protective cap 83 provided above the magnetic fluid seal 78 is different. That is, the protection cap 82 of the spindle motor in the first embodiment is provided on the hub member 47 side, whereas the protection cap 83 of the spindle motor in the second embodiment is fitted to the fixed support 11 outside. Is fixed. Specifically, the fixed support 11
The protective cap 83 is fitted into the annular groove formed in the above, and is held and fixed to the fixed support 11 by the snap ring 13. Therefore, foreign matter and hands from the outside of the spindle motor are not easily mixed or touched.
Since the distance from the outside of the spindle motor to the magnetic fluid seal 71 is also substantially increased, the effect of the protective cap 83 is further enhanced.

The armature coil derived from the armature 40 is electrically connected to a flexible circuit board 39 provided on the bottom 37 of the bracket 15. Then, unlike the first embodiment, the flexible circuit board 39 is drawn into the magnetic disk chamber via the upper surface of the projecting portion 19 of the bracket 15. Therefore, a fixing member 41 is attached to the inner peripheral surface of the outer peripheral wall 17 of the bracket 15 in order to prevent an accident in which the flexible circuit board 39 comes up and comes into contact with the rotor magnet 51 or the like. As shown in FIG. 4, the fixing member 41 is formed from an insulating resin material, and is formed by uneven portions 45a and 45b formed at both ends.
It is formed by annular engagement. An annularly formed fixing member 4
1 has an outer diameter set slightly larger than the inner diameter of the outer peripheral wall 17 of the bracket 15. This is fitted inside the outer peripheral wall 17 of the bracket 15, and the flexible circuit board 39 is pressed and held and fixed by the resilient force acting in the outer diameter direction, and the flexible member is fixed by the protrusion 43 of the fixing member 41. The floating of the circuit board 39 is prevented. Further, the fixing member 41 itself is attached to the bracket 1.
5 can be mounted very easily.

As shown in FIG. 3, the screw holes 81 for screwing the clamp members (not shown) are provided at six rotationally symmetrical positions in the hub member 47 as in the first embodiment, but are different. The point is that a communication groove 85 that connects these screw holes 81 to each other is formed on the hub member 47. The communication groove 85 allows the screw hole 81 to sufficiently penetrate the processing liquid, so that it is not necessary to make the screw hole 81 a through hole, and therefore, a sealing member (88 in FIG. 1) for sealing this through hole. ) Can be omitted. Further, when the clamp member is screwed to the hub member 47 by the communication groove, the stress of the screw acting on the screw hole 81 is dispersed, and the distortion generated in the hub member 47 is substantially absorbed. For this reason, an appropriate clamping force can be maintained.

As described above, the design can be freely changed or modified without departing from the gist of the present invention. That is, in the present embodiment, the so-called top bearing type spindle motor in which the bearing member is biased to one of the fixed columns and the hub member is rotatably supported by this bearing member has been described. It goes without saying that the present invention is also applied to a spindle motor of a fixed shaft type that rotatably supports a member. Further, there is no limitation on the type of the bearing member or the number of the bearing members. In addition, the size of the first and second protrusions,
Alternatively, if the side ends of the bearing member are always on the same side, the vertical positional relationship can be freely set.

[0025]

Since the spindle motor according to the present invention has the above-described structure, the following effects can be obtained. Since the hub member can be incorporated into the stationary member without the bearing member interposed therebetween, the tolerance of the thickness dimension of the bearing member is not affected, and the height dimension (interval) of the hub member with respect to the stationary member can be accurately determined. Can be positioned. Then, the gap between the hub member and the stationary member is made longer, and after assembling the two, the hub member is ground, so that an additional step of keeping the gap within a predetermined allowable tolerance is not required, and assembly is facilitated. Become. For this reason, the reading / writing operation of the magnetic disk device is reliably executed, and the sealing effect is enhanced by the labyrinth seal, so that a highly reliable spindle motor can be obtained.

[Brief description of the 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 sectional view showing the entirety of a spindle motor according to a second embodiment of the present invention.

FIG. 3 is a plan view of the spindle motor of FIG. 2;

FIG. 4 is a perspective view showing components used in the spindle motor of FIG. 2;

FIG. 5 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

 47, 48 Hub member 14, 15 Bracket 10, 11 Fixed column 21, 31 First protrusion 23, 72 Second protrusion 40, 47 Armature 51, 60 Rotor magnet 35, 52 Disk support 30, 39 Flexible Circuit board 53, 55 Ball bearing 62, 64 Ball bearing 71, 78 Magnetic fluid seal 82, 83 Protective cap 81, 84 Screw hole 43 Fixing member 85 Communication groove 13 Snap ring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-157255 (JP, A) JP-A-4-76149 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 5/173 H02K 5/15 H02K 5/22

Claims (2)

(57) [Claims] 1. A stationary member, a hub member on which a recording disk is mounted, and a bearing member provided between the stationary member and the hub member, wherein the hub member is provided with respect to the stationary member. a spindle motor comprising a rotatably supported Te, the side end portion of the inner ring of the bearing member is one in the stationary member
A first protruding portion formed on the body abuts, and a second end formed integrally with the hub member at a side end of the outer ring portion of the bearing member on the same side as the inner ring portion. A spindle motor having a protruding portion abutted thereon. 2. The first protruding portion of the stationary member and the second protruding portion of the hub member are opposed to each other in a radial direction with respect to a rotation axis with a small gap over the entire circumference. 2. The spindle motor according to claim 1, wherein the spindle motor is provided to form a labyrinth seal.