JP3891911B2 - Rotor axial biasing means - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spindle motor that rotationally drives an information recording disk, and more particularly to a brushless motor provided with a thrust-direction vibration preventing mechanism for a rotating shaft.
[0002]
[Prior art]
In recent years, information recording discs (hereinafter referred to as discs) such as CD-ROMs and DVDs have come to record a large amount of information at a high density. Has been. In such a motor, a cylindrical bearing housing is fixed to a central portion of a stator base that forms a stator, and a shaft inserted into a central portion of a rotor yoke that forms a rotor is rotatable inside the cylindrical portion of the bearing housing. A radial bearing and a thrust bearing that are supported on the bearing housing are disposed, and a stator core is fixed to a cylindrical outer peripheral portion of the bearing housing.
[0003]
In this stator core, an armature magnetic pole is formed by winding a drive coil around a plurality of arms protruding in the radial direction from the center. An annular magnet is fixed to the inner peripheral surface of the cylinder of the rotor yoke. The annular magnet has a magnetic pole divided in the circumferential direction, and the magnetic pole is disposed to face the armature magnetic pole of the stator.
[0004]
Usually, the in-plane weight distribution on the shaft is unbalanced in the disc. Accordingly, the motor with the disk mounted thereon is driven to rotate, and as the spindle motor rotates at a high speed, the dynamic centrifugal force of the recording disk is divided in the direction along the shaft to induce longitudinal vibration. As a result, there occurs a problem that an error in reading the disk information occurs and the vibration and noise of the drive device itself increase.
[0005]
As a method for solving this problem, a magnetism generator is disposed around the rotating shaft on the stator side of the rotor portion, and a shaft through hole is provided near the end of the bearing housing on the side facing the magnetism generator. A member formed of a magnetic material, and the rotor is biased toward the stator side by a magnetic attraction force acting between the magnetic generator and the member formed of the magnetic material It was solved.
As a method of arranging such a member, means for fixing the member to the housing by press-fitting or bonding has been taken (for example, Patent Document 1).
[0006]
[Patent Document 1]
JP 2002-195259 A (page 3, FIGS. 1 to 3)
[0007]
[Problems to be solved by the invention]
However, in the method in which the above-described member is disposed at the end of the bearing housing by press-fitting or bonding, there is a risk that the cap portion is loosened or detached due to vibration generated by the motor rotating at high speed.
In addition, the adhesive that protrudes in the process of manufacturing the motor may adhere to other members or cause dirt inside the motor.
[0008]
[Means for Solving the Problems]
As a means for solving such a problem, a non-magnetic bearing housing for supporting the bearing has a bearing on which a rotating shaft to which the rotor portion is fixed is rotatably attached, and is attached to the stator portion. On the stator side of the rotor portion, the first magnetic attracting means is disposed so as to surround the rotating shaft, and is arranged at the end of the bearing housing on the side facing the first magnetic attracting means disposed on the rotor portion. Is a spindle motor provided with a second magnetic attracting means so as to face the magnetic attracting means, and using the first and second magnetic attracting means to urge the rotor in the axial direction, The problem can be solved by having the engaging portion that the second magnetic attraction means can prevent the bearing housing from coming off in the axial direction.
[0009]
And it is good for the said engaging part to comprise so that engagement may become strong, when a rotor rotates. Specifically, the engaging portion is a screw portion applied to the end portion of the bearing housing and the second magnetic attractant, and one of the two members is a male screw portion and the other is a female screw portion. When the screw portion is turned in the same direction as the rotation direction of the rotor, the thread can be cut in the advancing direction to achieve the object.
[0010]
Moreover, it is good to comprise an engaging part by latching. Specifically, the latch includes a cutout groove extending in the axial direction from the end of the bearing housing, and a cutout extending in the same direction as the rotation direction of the rotor by forming a taper in the circumferential direction following the cutout groove. The problem can be achieved by using a bayonet with a tightening structure with a notch groove.
[0011]
As a means other than the above, a locking groove formed on the circumference of the bearing housing is formed, and the second magnetic attraction means has a claw for elastically engaging with the locking groove, and the bearing housing Even if it is made to engage from the side, the problem can be achieved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a perspective view of the cap portion 11 and the bearing housing 24 used in the embodiment of the present invention.
[0014]
The brushless motor of FIG. 1 includes a rotor portion R having a rotor yoke 1 and a stator portion S having a stator base 21 and a stator core 22.
The rotor portion R is formed in a cup shape from a magnetic material, and a central hole 1a is provided at the center of the bottom thereof, and the shaft 2 is fixed to the central hole 1a by press-fitting. The attracting magnet 3 is disposed on the stator side of the rotor portion R so as to surround the rotating shaft, and the driving magnet 4 is fixed to the inner peripheral side surface.
[0015]
On the other hand, in the stator portion S, a coil 23 is wound around a stator core 22 obtained by punching and laminating a plate-like magnetic metal plate with a press. A central annular portion 22 a of the stator core 22 is press-fitted into a bearing housing 24 attached to the stator base 21.
[0016]
1 and 2, the radial bearing 25 is press-fitted into the central hole bottom 24b of the bearing housing 24 so as to be in contact with the inner peripheral surface 24a of the central hole of the bearing housing 24. In the vicinity of the stator side end of the bearing housing 24, a male screw portion 24c is formed.
Then, a female screw 11a is formed so as to coincide with the male screw portion 24c, a shaft through hole 11b is provided, and a cap portion 11 formed of a magnetic material is a bearing in which the male screw portion 24c is formed. In the vicinity of the end of the housing, it is fastened via screw portions provided to each other. The male screw and the female screw are threaded in the direction of advancement when rotated in the same direction as the rotation direction of the rotor.
[0017]
Here, when the rotor portion R and the stator portion S, each of which is configured as described above, are assembled, the cap portion 11 and the attracting magnet 3 are adjusted so that they face each other with an appropriate gap. .
[0018]
With the above configuration, the cap portion 11 is fastened to the bearing housing 24 by screwing, so there is no need to fix the cap portion 11 with an adhesive or the like. It is possible to solve problems such as adhesion.
[0019]
Further, the end portion of the bearing housing 24 is formed with a male screw portion 24c that is threaded in the direction of advancement when rotated in the same direction as the rotation direction of the rotor R. The female screw portion 11a is formed so as to match the male screw portion 24c. When the rotor R rotates, the cap portion 11 and the bearing housing 24 fastened via both screw portions are strongly against the bearing housing 24 due to the magnetic force of the suction magnet 3 disposed in the rotor portion. A force acts in the fastening direction.
Therefore, even if the attraction force of the rotor is increased, the cap portion 11 does not loosen with respect to the bearing housing 24. Therefore, the attraction magnet 3 and the cap portion 11 are always attracted stably by the magnetic force of the attraction magnet 3. And vibration of the rotor can be prevented.
[0020]
The perspective view of the cap part 12 and the bearing housing 44 shown in FIG. 3 is a first modification of the cap part 11 and the bearing housing 24 used in the embodiment of the present invention.
[0021]
A female screw portion 44 a is provided on the inner peripheral side surface of the end portion of the bearing housing 44 shown in FIG. 3, and a male screw portion 12 a is provided on the outer peripheral side surface of the end portion of the cap portion 12. That is, in the first modification, the positional relationship between the “male screw part” and the “female screw part” shown in the embodiment in FIGS. 1 and 2 is reversed.
Therefore, even if a screw portion is provided as shown in FIG. 3, the same effect as in the embodiment can be obtained.
[0022]
The perspective view of the cap part 13 and the bearing housing 64 shown in FIG. 4A is a second modification of the cap part 11 and the bearing housing 24 used in the embodiment of the present invention.
[0023]
The bearing housing 64 shown in FIG. 4A has an end of the bearing housing 64 on the side facing the attraction magnet 3 disposed in the rotor portion R when the bearing housing 64 is assembled to the stator. One or more notches 64a extend from the portion in the direction of the stator base, and the notches 64a are formed to extend from an appropriate portion in the rotation direction of the rotor. Then, the protrusion 13a is formed so as to match the notch 64a, and the shaft 13 is provided with a shaft through hole, and the cap 13 formed of a magnetic body is formed at the end of the bearing housing where the notch 64a is formed. It is fastened to the part via the notch part 64a and the protrusion part 13a.
[0024]
Moreover, since the notch part is provided in the rotation part of the rotor R at the edge part of the bearing housing 64, the cap part 13 fastened via the protrusion part 13a and the notch part 64a, and the bearing housing 64, When the rotor R rotates, a force acts in a direction in which the cap portion 13 is strongly fastened to the bearing housing 64 by the magnetic force of the suction magnet 3 disposed in the rotor portion.
Accordingly, even if the attraction force of the rotor is increased, it does not loosen against the force in the thrust direction, so that the attraction magnet 3 and the cap portion 13 can always be attracted stably by the magnetic force of the attraction magnet 3. Thus, the reliability of preventing the rotor from coming off is improved.
[0025]
Since the cap part 13 is fastened by being guided by the notch part 64a provided in the bearing housing 64, the cap part 13 does not need to be fixed with an adhesive or the like. Furthermore, it is possible to solve problems such as scattering of the adhesive protruding in the production process and the like and adhesion to other members.
[0026]
FIG. 4 (b) shows a notch 64b in which the notch 64a shown in FIG. 4 (a) has a tapered shape 64c.
Like the notch portion 64b shown in FIG. 4 (b), by providing a tapered shape 64c in a portion extending in the rotational direction of the rotor, the protrusion 13a provided on the cap portion by the rotation of the rotor is , It will bite into the tapered portion. Thus, the coupling between the cap portion and the bearing housing can be strengthened.
[0027]
The perspective view of the cap part 14 and the bearing housing 84 shown in FIG. 5A is a third modification of the cap part 11 and the bearing housing 24 used in the embodiment of the present invention.
[0028]
The bearing housing 84 shown in FIG. 5 (a) is provided with one or more protrusions 84a. Further, the cap portion 14 formed of a magnetic material is formed with a notch portion 14a that matches the projection portion 84a so that the cap portion can be assembled to the end portion of the bearing housing 84. The part is formed to extend from an appropriate part in the direction opposite to the direction of rotation of the rotor. And the cap part 14 and the bearing housing 84 are fastened via the projection part 14a and the notch part 84a.
[0029]
Further, since the notch portion extends from the appropriate portion of the cap portion 14 in the direction opposite to the rotation direction of the rotor R, the cap housing 14 and the bearing housing 84 fastened via the projection portion 84a and the notch portion 14a. When the rotor R rotates, the cap portion 14 is subjected to a force in a direction in which the cap portion 14 is strongly fastened to the bearing housing 84 by the magnetic force of the suction magnet 3 disposed in the rotor portion.
Accordingly, even if the attraction force of the rotor is increased, it does not loosen against the force in the thrust direction, so that the attraction magnet 3 and the cap portion 14 can always be attracted stably by the magnetic force of the attraction magnet 3. Thus, the reliability of preventing the rotor from coming off is improved.
[0030]
When configured as described above, the bearing housing 84 is fastened by the projection 84a being guided by the notch portion 14a provided in the cap portion 14, so there is no need to fix it with an adhesive or the like. Furthermore, it is possible to solve problems such as scattering of the adhesive protruding in the production process and the like and adhesion to other members.
[0031]
FIG. 5 (b) shows a notch 14b in which the notch 14a shown in FIG. 5 (a) has a tapered shape 14c.
Like the notch portion 14b shown in FIG. 5 (b), by providing the tapered shape 14c in the portion extending in the rotation direction of the rotor, the protrusion 84a provided on the cap portion by the rotation of the rotor is , It will bite into the tapered portion. Thus, the coupling between the cap portion and the bearing housing can be strengthened.
[0032]
The perspective view of the cap portion 15 and the bearing housing 94 shown in FIG. 6 is a fourth modification of the cap portion 11 and the bearing housing 24 used in the embodiment of the present invention.
[0033]
In the bearing housing 94 shown in FIG. 6, a locking groove 94a is formed on the outer periphery of the housing, and the cap portion 15 has a claw 15a to be engaged with the locking groove 94a with elasticity. Both members are configured to be engaged from the side of the bearing housing 94.
[0034]
If comprised as mentioned above, since the cap part 15 will be fastened when a nail | claw part and a latching | locking part engage with the bearing housing 94, since it is not necessary to fix with an adhesive agent etc., it protruded in the production process etc. Problems such as adhesive scattering and adhesion to other members can be solved.
[0035]
【The invention's effect】
If each part is configured as in the present invention, an adhesive or the like is not required when the cap part is arranged on the bearing housing, so that the adhesive inside the motor or the adhesion to other members in the assembly process of the motor can be avoided. It becomes possible to eliminate the cause of dirt.
In addition, since the fastening portion of the cap portion and the bearing housing is configured to be strongly fastened when the rotor rotates, it is possible to prevent the cap portion from loosening or coming off due to vibration generated by the high-speed rotation of the motor. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment.
FIG. 2 is a perspective view of a cap portion and a bearing housing used in the embodiment.
FIG. 3 is a perspective view of a first modification of the cap portion and the bearing housing used in the embodiment.
FIG. 4 is a perspective view of a second modification of the cap portion and the bearing housing used in the embodiment.
FIG. 5 is a perspective view of a third modification of the cap portion and the bearing housing used in the embodiment.
FIG. 6 is a perspective view of a fourth modification of the cap portion and the bearing housing used in the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor yoke 3 Suction magnet 11, 12, 13, 14, 15 Cap part 11a 44a Female thread part 11b Through-hole 13a, 84a Projection part 14a, 64a Notch part 15a Claw part 21 Stator bases 24, 44, 64, 84, 94 Bearing housing 12a, 24c Male thread 94a Locking groove

Claims (4)

A non-magnetic bearing housing is mounted on the stator portion and has a bearing on which a rotating shaft to which the rotor portion is fixed is rotatably attached. The first magnetic is provided on the stator side of the rotor portion. An attracting means is disposed surrounding the rotating shaft, and a second magnetic member is disposed at the end of the bearing housing on the side facing the first magnetic attracting means so as to face the first magnetic attracting means. In a spindle motor that includes an attracting means and uses the first and second magnetic attracting means to bias the rotor in the axial direction,
To said second magnetic attracting means are bearing housings, have a engaging portion to allow retained axially,
The rotor is axially biased by the engagement portion, wherein the engagement is strengthened by rotation of the rotor. The engaging portion is a screw portion applied to the end portion of the bearing housing and the second magnetic attracting body, and one of the two members is a male screw portion and the other is a female screw portion. axial biasing means of the rotor according to claim 1, characterized in that is threaded is applied to the direction of travel and turn in the same direction as the rotation direction of the rotor. A non-magnetic bearing housing is mounted on the stator portion and has a bearing on which a rotating shaft to which the rotor portion is fixed is rotatably attached. The first magnetic is provided on the stator side of the rotor portion. An attracting means is disposed surrounding the rotating shaft, and a second magnetic member is disposed at the end of the bearing housing on the side facing the first magnetic attracting means so as to face the first magnetic attracting means. In a spindle motor that includes an attracting means and uses the first and second magnetic attracting means to bias the rotor in the axial direction,
The second magnetic attraction means has an engaging portion that can prevent the bearing housing from coming off in the axial direction;
The engaging portion is constituted by a latch,
The latch is a notch groove extending in the axial direction from the end of the bearing housing, and a notch groove extending in the same direction as the rotation direction of the rotor by forming a taper in the circumferential direction following the notch groove. features and to Carlo over axial biasing means data that it has to bayonet locking arrangement. A non-magnetic bearing housing is mounted on the stator portion and has a bearing on which a rotating shaft to which the rotor portion is fixed is rotatably attached. The first magnetic is provided on the stator side of the rotor portion. An attracting means is disposed surrounding the rotating shaft, and a second magnetic member is disposed at the end of the bearing housing on the side facing the first magnetic attracting means so as to face the first magnetic attracting means. In a spindle motor that includes an attracting means and uses the first and second magnetic attracting means to bias the rotor in the axial direction,
The second magnetic attraction means has an engaging portion that can prevent the bearing housing from coming off in the axial direction;
The engaging portion, the engaging groove on the circumference of the bearing housing is formed, the second magnetic attraction means has a pawl to engage with the elastic to the locking grooves, the side of the bearing housing features and to Carlo over axial biasing means data that it has to engage the.

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