JP3121664B2 - Motor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to
The present invention relates to a motor device in which a stator core is fixedly held and a rotating unit is rotatably supported via a rolling bearing existing only on one side in the axial direction with respect to the stator core.

[0002]

2. Description of the Related Art As in a so-called top bearing type spindle motor, a stator core is fixedly held on the outer peripheral side of a fixed support, and a rolling existing only on one axial side with respect to the stator core. In a motor device in which a rotating portion is rotatably supported via a bearing, as means for preventing the lubricant of the rolling bearing from scattering outside the motor device, for example, an opening of a bowl-shaped rotor hub constituting the rotating portion It has been practiced to form a labyrinth seal between the end and the fixed bracket facing it, but this is not always sufficient.

On the other hand, the inner diameter and the like of the stator core in the above-described motor device need to correspond to the required performance, size, and the like. It is also necessary to change the diameter size, the inner diameter size of the inner ring of the ball bearing fixed to the outer peripheral side of the fixed support, and also the inner diameter size of the rotating portion that fixes the outer ring of the ball bearing, etc., which increases the manufacturing cost. Was a factor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the prior art, and has as its object to fix and hold a stator core on an outer peripheral side of a fixed support. In a motor device in which a rotating part is rotatably supported via a rolling bearing existing only on one side in the axial direction with respect to the stator core, the lubricant of the rolling bearing is sufficiently prevented from scattering to the outside of the motor device. A motor device that does not need to change the outer diameter of the fixed support and the inner diameter of the inner ring of the ball bearing fixed to the outer circumference of the fixed support, even if the inner diameter of the stator core is slightly changed. Is to provide.

[0005]

To achieve SUMMARY OF to the above objects, the motor apparatus of the present invention, the outer peripheral side of the fixed post, antivibration
A motor device in which a stator core is fixedly held via a cylindrical holding member made of a material, and a rotating part is rotatably supported by a rolling bearing existing only on one side in the axial direction with respect to the stator core. The fixed seal part forming a part of the holding member and the rotating seal part rotating together with the rotating part have a radial length at a radial position intermediate between the outer circumference of the inner race of the rolling bearing and the inner circumference of the outer race. The rolling bearing and the stator core are opposed to each other with a sufficiently small annular gap therebetween, and the space between the rolling bearing and the stator core is closed by a rotary seal and a fixed seal except for the annular gap.

[0006]

[Action] on the outer peripheral side of the fixed post, since the stator core is fixed and held through the vibration insulator made of tubular retaining member, vibrations
In addition to the suppression effect, even if the inner diameter of the stator core is slightly changed, if only the outer diameter of the holding member is changed, it is fixed to the outer diameter of the fixed support or the outer peripheral side of the fixed support. It is not necessary to change the inner diameter of the inner ring of the ball bearing.

[0007] A fixed seal part forming a part of the holding member and a rotary seal part rotating together with the rotary part are provided at a radial position intermediate between the inner ring and the outer ring of the rolling bearing. Parts, facing each other, between the rolling bearing and the stator core, except for the annular gap,
It is closed by the rotating seal part and the fixed seal part. Since the annular gap is located at a radial position intermediate between the outer periphery of the inner ring of the rolling bearing and the inner periphery of the outer ring , lubricant flowing along the inner ring and the outer ring may leak from the annular gap. Coupled with the fact that it is effectively avoided, the lubricant of the rolling bearing is prevented from being scattered outside the motor device through the space between the rolling bearing and the stator core.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a spindle motor device for driving a hard disk as one embodiment of the motor device of the present invention. Of course, the motor device of the present invention can be used for driving various other recording media, or used for other purposes.

Reference numeral 10 is a fixed support made of a ferromagnetic material.
The outer diameter of the fixed column 10 is substantially constant, and a screw hole 12 having an upper opening is provided at the upper end in FIG.

Reference numeral 14 denotes a bracket. Bracket 14
1 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 fixed column 10 is fitted and fixed inside the inner peripheral wall 22 of the annular groove 16. 26 is a circuit board provided at the bottom of the annular groove 16, and 28 is a magnetic pole position detecting element. Reference numeral 30 denotes a flexible lead board having one end connected to the circuit board 26, which is drawn out to the lower surface side of the bracket 14, that is, outside the spindle motor device, through a through hole 32 provided in the bottom plate of the bracket 14. 34 is a through hole 3
2 is a filler for sealing.

Reference numeral 36 denotes a cylindrical holding member made of synthetic resin. The holding member 36 has a rotationally symmetric shape, and has a flange-shaped fixed seal portion 38 having the largest outer diameter at the upper end. The lower portion of the holding member 36 has a small outer diameter portion 40 and a small outer diameter portion 40.
An intermediate / outer diameter portion 42 is provided between the fixed seal portion 38 and the fixed seal portion 38.
The holding member 36 is externally fixed to the base of the fixed column 10 in a state where the stator core 46 having the stator coil 44 wound around the small outer diameter portion 40 is externally fixed. The material of the holding member 36 is not limited to a synthetic resin, but by selecting a material having an anti-vibration effect, a vibration suppressing effect can be exerted.

Reference numeral 48 denotes a substantially cylindrical aluminum rotor hub. Outer peripheral wall 5 of rotor hub 48 in FIG.
A disk support portion 52 extends over the entire periphery of the lower part of the outer peripheral portion 0, and a hard disk (not shown) is externally fitted and fixed above the disk support portion 52 on the outer peripheral portion of the outer peripheral wall portion 50. You. 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 are radially opposed to each other with a slight gap. An inner peripheral portion of the upper portion of the rotor hub 48 is formed in a small-diameter inner peripheral portion 54, and a portion of the rotor hub 48 below the small-diameter inner peripheral portion 54 is enlarged 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.
A cylindrical rotor magnet 60 is fitted and fixed inside the inside 8. And mainly these rotor hubs 48,
The rotor yoke 58 and the rotor magnet 60 constitute a rotating unit.

A rotor hub 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) arranged in a fixed preload state in FIG. The small-diameter inner peripheral portion 54 is rotatably supported. The outer rings 62o and 64o of the upper and lower ball bearings 62 and 64 are connected to the small-diameter inner peripheral portion 5 of the rotor hub 48.
The inner rings 62i and 64i are bonded and fixed to the outer peripheral portion of the fixed support 10. Upper and lower outer rings 62o
An annular spacer 66 is interposed between 64o. The inner peripheral portion of the spacer 66 is slightly spaced from the outer peripheral surface of the fixed column 10.

Reference numeral 68 denotes a substantially annular flat rotary seal portion whose outer peripheral portion is bent upward. This rotary seal part 68
The outer peripheral portion is bonded to the annular surface portion 70 between the small-diameter inner peripheral portion 54 and the large-diameter inner peripheral portion 56 of the rotor hub 48, so that the lower end of the small-diameter inner peripheral portion 54 of the rotor hub 48 is coaxial with the rotor hub 48. It is fixed in the shape. As a result, the rotating seal portion 68 and the fixed seal portion 38 separate the inner races 62i and 64i and the outer races 62o of the lower ball bearings 62 and 64 from each other.
At an intermediate position in the radial direction between the upper and lower ball bearings 62 and 64 and the stator core 46, except for the annular gap 72, the rotation between the upper and lower ball bearings 62 and 64 and the stator core 46 is opposite. It is closed by the seal part 68 and the fixed seal part 38. As shown in FIG. 1, the radial position where the rotary seal portion 68 and the fixed seal portion 38 face each other is desirably substantially in the middle of the middle between the inner ring 64i and the outer ring 64o of the lower ball bearing 64. It may be slightly biased to the side.

Numeral 74 is a magnetic fluid seal. The two annular pole pieces 76 constituting the magnetic fluid seal 74 and the annular permanent magnet 78 sandwiched therebetween are formed by a rotor hub 48.
Is fixed to a slightly enlarged portion of the upper end of the small diameter inner peripheral portion 54. A magnetic fluid 80 is held between the inner peripheral portion of the annular pole piece 76 and the outer peripheral surface of the fixed column 10. Reference numeral 82 denotes an annular flat plate-shaped protective cap fixed to the rotor hub 48 above the magnetic fluid seal 74.

Reference numeral 84 denotes a screw hole provided in the rotor hub 48 for screwing a hard disk fixing clamp member. The portion of the screw hole 84 that opens inside the spindle motor device is sealed by a seal member 88. This is to prevent metal powder and the like from flying outside through the inside of the spindle motor device and attaching to the hard disk surface.

In this spindle motor device, since the stator core 46 is fixedly held on the outer peripheral side of the fixed column 10 via the holding member 36, even if the inner diameter of the stator core 46 is slightly changed, the holding member If only the outer diameter of the small outer diameter portion 40 is changed, the outer diameter of the fixed support 10 and the ball bearing 6 fixed to the outer peripheral side of the fixed support 10 are changed.
It is not necessary to change the inner diameter dimensions and the like of the inner races 62i and 64i of the 2.64, and it is possible to share precision parts such as the fixed support 10 and the ball bearings 62 and 64.

The lower side of the upper and lower ball bearings 62 and 64 has a rotary seal portion 6 except for an annular gap portion 72 located at a radial position between the inner ring 64i and the outer ring 64o of the lower ball bearing 64.
8 and the fixed seal portion 38. Since the annular gap 72 is located at a radial position between the inner ring 64i and the outer ring 64o of the lower ball bearing 64, the lubricant flowing along the inside of the inner ring 64i and the outer ring 64o may leak from the annular gap 72. Effectively avoided, the lubricant of the upper and lower ball bearings 62 and 64 is prevented from being scattered outside the spindle motor device through the space between the ball bearings 62 and 64 and the stator core 46. In particular,
In this spindle motor device, the rotor hub 48 rotates, and with this rotation, a centrifugal force acts radially outward on the rotary seal portion 68 provided integrally with the rotor hub 48. Therefore, even if the lubricant of the lower ball bearing 64 tries to flow downward, it can be retained inside the rotary seal portion 68 (upper side in FIG. 1), and leakage from the annular gap portion 72 can be reliably prevented. it can. 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, lubricant or the like from the inside of the spindle motor device. The leakage of the fine particles and the like to the outside through the voids is prevented by the labyrinth seal-like effect. On the other hand, the upper sides of the upper and lower ball bearings 62 and 64 are sealed by a magnetic fluid seal 74.

Furthermore, since the inner peripheral portion of the spacer 66 is separated from the outer peripheral surface of the fixed support 10 by a small gap, the air circulation between the upper ball bearing 62 and the lower ball bearing 64 is sufficiently ensured. The sealing effect of the rotating seal portion 68 and the fixed seal portion 38 and the effectiveness of the magnetic fluid seal 74, and the sealing by 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 16 of the bracket 14 Both effects are enhanced, and it is possible to effectively avoid the possibility that lubricant fine particles and the like of the upper and lower ball bearings 62 and 64 scatter outside the spindle motor device and stain the hard disk surface.

FIG. 2 is a sectional view of another spindle motor device for driving a hard disk. This can be used for driving various other recording media, or used for other purposes.

Reference numeral 100 denotes a bracket. Bracket 1
Reference numeral 00 has a circular concave portion 102 having an upper opening in FIG. 2, and a fixed support 104 is erected at the center thereof.

A stator core 110 is fixed to an intermediate outer peripheral portion of the fixed support 104 via upper and lower annular holders 106 and 108 formed of a material having a vibration-proof effect such as a synthetic resin. A first ball bearing 114 is disposed on the outer periphery of the fixed support 104 above the stator core 110 in FIG. 2, and a second ball bearing 116 is disposed on the outer periphery of the fixed support 104 below the stator core 110 in FIG. It is a ball bearing.

The upper and lower inner peripheral corners of the stator core 110 are held by the upper and lower annular holders 106 and 108, respectively, so that a vibration suppressing effect can be obtained. In addition, even if any of the inner diameter of the stator core 110, the inner diameter of the first ball bearing 114 and the second ball bearing 116, or the outer diameter of the fixed support column needs to be slightly changed, all of these dimensions are changed. Even without doing so, it is possible to cope with this by changing the dimensions of the upper and lower annular holders 106 and 108. Therefore, it is possible to use common parts. Reference numeral 112 denotes a stator coil wound around the stator core 110.

Reference numeral 118 denotes an aluminum rotor hub. The rotor hub 118 has a substantially cylindrical shape, and has a disk support 120 outside the lower end in FIG. The rotor hub 118 has a first small-diameter inner peripheral portion 122 at an upper portion and a large-diameter internal peripheral portion 124 below the first smaller-diameter inner peripheral portion 124.
It is rotatably supported by the fixed support 104 via a ball bearing 114, an annular bush member 126 and a second ball bearing 116. The annular bush member 126 interposed between the lower end of the rotor hub 118 and the second ball bearing 116 has an inward projection 128 located below the second ball bearing 116. The inwardly protruding portion 128 reaches the vicinity of the outer peripheral surface of the fixed column 104 at a slight distance in the axial direction from the second ball bearing 116. Lubricant particles and the like of the bearings 114 and 116 are prevented from leaking out of the spindle motor device.

A cylindrical member 130 made of a ferromagnetic material is externally fitted and fixed above the first ball bearing 114 on the outer peripheral portion of the fixed support 104, and the cylindrical member 130 and the rotor hub 1 are fixed.
18, the magnetic fluid seal 13
2 are provided. 134 is a pole piece, 136 is a permanent magnet, and 137 is a magnetic fluid. 138 is
It is a protective cap.

A cylindrical rotor yoke 140 is fixed to the large-diameter inner peripheral portion 124 of the rotor hub 118, and a cylindrical rotor magnet 142 is fitted and fixed inside the rotor yoke 140 so as to face the stator core 110 in the radial direction. I have.
144 is a screw hole for screwing a clamp member for externally fitting and fixing the hard disk to the rotor hub 118;
146 is a seal member for sealing the opening of the screw hole 144 to the inside of the spindle motor.

[0027]

According to the motor device of the present invention, the space between the rolling bearing and the stator core is the outer circumference of the inner race of the rolling bearing and the outer race.
Except for the annular gap located at the intermediate radial position of the inner circumference of the rolling bearing, the lubricant of the rolling bearing is closed by the rotating seal and the fixed seal, so that the lubricant passes between the rolling bearing and the stator core. The ball bearing is effectively prevented from being scattered outside the motor device, and even if there is a slight change in the inner diameter of the stator core or the like, the outer diameter of the fixed support or the outer periphery of the fixed support. Since there is no need to change the inner diameter of the inner ring, precision parts such as fixed columns and rolling bearings can be shared, which is effective in reducing costs.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spindle motor device for driving a hard disk.

FIG. 2 is a sectional view of a spindle motor device for driving a hard disk.

[Description of sign]

 REFERENCE SIGNS LIST 10 fixed support 36 holding member 38 fixed seal 46 stator core 48 rotor hub 58 rotor yoke 60 rotor magnet 62 ball bearing 62i inner ring 62o outer ring 64 ball bearing 64i inner ring 64o outer ring 68 rotating seal part 72 annular gap

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshiyuki Kodaira 1145-4 Tagiri, Iijima-cho, Kamiina-gun, Nagano Prefecture Inside Nagano Nidec Corporation (56) References JP-A-3-285545 (JP, A) JP-A Hei 1-157255 (JP, A) Actually open Hei 4-12155 (JP, U) Special table Hei 4-502847 (JP, A) International Publication 90/9051 (WO, A1) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H02K 5/173 H02K 5/15 H02K 21/22 F16J 15/43

Claims (1)

(57) [Claims] 1. A stator core is fixedly held on an outer peripheral side of a fixed support via a cylindrical holding member made of an anti-vibration material, and a rolling bearing existing only on one axial side with respect to the stator core. A motor device in which a rotating part is rotatably supported, wherein a fixed seal part forming a part of the holding member and a rotating seal part rotating together with the rotating part are provided on an outer periphery of an inner ring of a rolling bearing. And at an intermediate radial position between the inner circumference of the outer ring and the radial gap is opposed by a sufficiently small annular gap, and between the rolling bearing and the stator core, except for the annular gap, A motor device closed by a rotating seal portion and a fixed seal portion.