JPH0638455A - Spindle motor - Google Patents

Abstract

PURPOSE:To attach and fix a rotational load member with accuracy without giving damage to a bearing member by providing a through hole in a static member and inserting an insertion member when installing the rotational load member on a rotor hub, and abutting the top against the bottom of the rotor hub, and holding the rotary hub statically. CONSTITUTION:In a spindle motor, which has a shaft 1, a bracket 2, and a rotor hub 5 being supported by the shaft 1 through bearings 3 and 4, when installing rotational load, for example, a polygonal mirror 6, the polygonal mirror 6 is placed on the rotor hub 5 to begin with. Next, the insertion part 512 of an insertion member 50 is inserted into the through hole 9 provided in the bracket 2 from the bottom of the spindle motor, and the top 52 is abutted against the bottom 12 of the rotor hub 5. Next, a mounting screw 8 is screwed in the mounting hole 26 of the rotor hub 5 through a clamp member 7 so as to fix the polygonal mirror 6. Accordingly, the push-up force F of the insertion member 50 and the press-down force P of the mounting screw 8 balance, and they do not give damage to the bearings 3 and 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary polygon mirror used in a laser scanner device and a spindle motor for driving a so-called rotary load member such as a recording medium mounted in an optical / magnetic disk drive device.

[0002]

2. Description of the Related Art A spindle motor is known as a means for driving a rotary load member. FIG. 9 shows a spindle motor incorporated in, for example, a laser scanner device, which has already been used by the present applicant for rotationally driving a polygon mirror for optical deflection. FIG. 4 is a sectional view showing a right half of the proposed spindle motor.

In the figure, a is a shaft, which is fixed to a bracket b. c is a rotor hub in the shape of an inverted bowl, which has a shaft a through bearings e and f.
It is rotatably supported by. An annular rotor magnet k is arranged inside an annular side wall provided below the rotor hub c. Further, j is an armature attached to the bracket b, and is provided so as to face the rotor magnet k. The rotor hub c is rotationally driven by the electromagnetic induction action between the armature j and the rotor magnet k.

A polygonal mirror d is mounted on the upper surface of the rotor hub c. The polygonal mirror d is held and fixed integrally with the rotor hub c by the clamp member g coming into contact with the upper surface thereof and the male screw h being screwed to the rotor hub c to fix the clamp member. For example, four places are screwed by the male screw h on the circumference of the rotor hub c at equal angular intervals. The polygon mirror d is generally formed separately from the rotor hub c, and is generally sandwiched between the clamp member g and the rotor hub c.

[0005]

In the structure of the spindle motor described above, when the polygon mirror d is fixed by using the clamp member g, the polygon mirror d is placed on the rotor hub c and the male screw h is attached to the rotor hub c. It will be screwed in,
The pressing force at this time (in this case, the force acting downward in the rotation axis z direction, that is, the force acting downward in FIG. 9) becomes a stress and is transmitted to the bearings e and f via the rotor hub c.

However, the stress due to the pressing force does not act evenly on the outer ring portions of the bearings e and f on their circumferences, but acts in an unbalanced state. That is, the stress acts on the outer ring portion of each of the bearings e and f in a state of being eccentric with respect to the rotation axis line z while corresponding to the screwed portion of the male screw h.

For this reason, the bearings e and f are damaged by stress and generate vibrations and noises, and it becomes difficult to rotatably support the rotor hub c with high precision. The light deflection accuracy of d is significantly reduced. The present invention has been made in view of the above facts, and it is an object of the present invention, when attaching a rotation load member to a rotor hub by a clamp member, without damaging a bearing member that rotationally supports the rotor hub, and with accuracy. It is to provide a spindle motor that can be mounted and fixed well.

[0008]

In order to achieve the above object, in a spindle motor of the present invention, a stationary member, a bearing member mounted on the stationary member, and a relative surface of the stationary member via the bearing member. A spindle motor having a rotor hub rotatably supported, a rotor magnet mounted on the rotor hub, and an armature mounted on a stationary member facing the rotor magnet, wherein the rotor hub includes a rotary load member. Is fixed by a clamp member. The stationary member is formed with a through hole that penetrates inward from the outside along the central axis of rotation and has an inner open end facing the bottom surface of the rotor hub. Further, the armature is formed with a notch or an insertion hole corresponding to the through hole. When fixing the rotation load member to the rotor hub, insert the insertion member through the through hole and the notch or the insertion hole, and bring the tip end portion of the insertion member into contact with the bottom surface portion of the rotor hub. The rotary load member is attached to the rotor hub while the rotor hub is held stationary.

[0009]

According to the spindle motor of this structure, the stationary member is provided with the through hole into which the insertion member can be inserted, and the armature is also provided with the notch or the insertion hole into which the insertion member can be inserted. Therefore, from the outside of the spindle motor, the insertion member can be inserted through the through hole of the stationary member and the notch or insertion hole of the armature, and the tip of the insertion member can be brought into contact with the bottom surface of the rotor hub. The rotor hub is held stationary by the insert. When the rotary load member is attached and fixed to the rotor hub in this state, the pressing force acting at that time is canceled by the supporting force of the insertion member, and a component force inward of the spindle motor is hardly generated. Therefore, the stress due to this pressing force does not substantially act on the bearing member that rotatably supports the rotor hub, and damage to the bearing member is prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1 to 8 show an embodiment of a spindle motor according to the present invention. 1 to 5, the laser scanner device is incorporated,
A spindle motor that rotationally drives a polygon mirror for deflecting light is shown. FIG. 1 is a cross-sectional view showing the right half of the spindle motor showing a state in which a polygon mirror is attached.
FIG. 2 is a bottom view of the spindle motor in FIG. 1 as viewed from below. 3 and 4 show a state of the spindle motor alone without the polygon mirror attached. That is, FIG. 3 is a cross-sectional view showing the right half of the spindle motor, and FIG. 4 is a plan view of the spindle motor in FIG. FIG. 5 is a plan view showing a stator core of the spindle motor of FIG.

In FIGS. 1 to 5, reference numeral 2 denotes a bracket which is a part of a stationary member, and is made of an aluminum material, and is fitted coaxially outwardly with respect to the rotation center axis 10 in a fitting small diameter portion. 33, a cylindrical portion 34, and a flat portion 46
And are integrally formed. One end portion (lower side in the figure) of the shaft 1 is fixed to the central axis portion of the bracket 2, that is, the rotation central axis portion 10 by press fitting or the like, and is integrally fixed to the bracket 2. The shaft 1 as a stationary member is made of, for example, an iron material.

Inner ring portions of the bearings 3 and 4 are mounted on the outer peripheral surface 43 of the shaft 1 at the substantially central portion and the other end portion (upper side in the figure). The outer ring portions of the bearings 3 and 4 are fitted into the bearing housing portion 35 of the rotor hub 5. The rotor hub 5 supports the hub portion 15 on which the polygonal mirror 6 that is a rotation load member is mounted, the annular protruding portion 44 to which the clamp member 7 used for holding and fixing the polygonal mirror 6 is attached, and the annular magnet 14. It has a rotor yoke portion 16. The hub portion 15 and the annular protruding portion 44 are integrally formed of an aluminum material, and the rotor yoke portion 16 is fixed thereto by press fitting or the like. The rotor yoke 16 closes the magnetic path of the annular magnet 14,
Ferromagnetic material is used.

The annular magnet 14 fixed to the rotor yoke 16 by adhesion or the like is composed of a rotor magnet portion 22 and
An FG (frequency power generation) magnet portion 18 is integrally formed, and these are magnetized with different numbers of magnetic poles.
The rotor magnet portion 22 is the cylindrical portion 3 of the bracket 2.
4 is arranged so as to face the armature 24 mounted on the No. 4 armature. Further, the FG magnet portion 18 is arranged to face the flexible circuit board 20 attached on the flat portion 46 of the bracket 2. The flexible circuit board 20 has a comb-tooth-shaped conductive pattern (not shown) formed on a portion 21 corresponding to the FG magnet portion 18. Further, on the flexible circuit board 20, a rotation detecting magnetic sensor 23 arranged corresponding to the rotor magnet portion 22 is mounted. By mounting putty or the like on the annular recess 17 provided on the outer peripheral edge of the annular magnet 14, the rotational balance of the rotor hub 5 can be adjusted.

On the upper surface of the hub portion 15 of the rotor hub 5, a flat flat portion 28 slightly protruding upward is formed, and similarly, on the annular projecting portion 44 of the rotor hub 5, a large diameter portion 27 is formed. The polygonal mirror 6 is held at the flat portion 28 and the large diameter portion 27. Two mounting holes 26 for screwing the clamp member 7 with the mounting screws 8 are provided on the upper end surface of the annular protrusion 44, and have a rotational symmetry of 180 degrees (with respect to the rotation center axis 10). It is located in. The polygonal mirror 6 held by the rotor hub 5 is screwed into a mounting hole 26 via a clamp member 7 by a mounting screw 8 and fixed integrally. In this case, the polygonal mirror 6 has its upper surface portion 37 in contact with the pressing surface 38 of the clamp member 7, and the lower surface portion 31 of the polygonal mirror 6 in contact with the flat portion 28 of the rotor hub 5 (hub portion 15). Further, the inner diameter portion 30 of the polygon mirror 6 is brought into contact with the large diameter portion 27 of the annular protrusion 44. In addition,
In addition to the mounting holes 26, 26, the rotor hub 5 (upper surface of the hub portion 15) shown in FIG. 4 is provided with two groove portions 32 formed in 180-degree rotational symmetry. This groove 32,
32 is used for positioning used when holding and fixing the polygonal mirror 6 to the rotor hub 5.

In the above-mentioned structure, the rotor hub 5 is provided with respect to the shaft 1 (and the bracket 2 as well).
It is rotatably supported via a pair of bearings 3 and 4, and is relatively rotated by the electromagnetic action of the rotor magnet portion 22 and the armature 24. A mounting screw 39 screwed to one end portion (upper side in the drawing) of the shaft 1 is used for fixing the disc-shaped spring 40 via the flat washers 41 and 42. The disc-shaped spring 40 urges the inner ring portion of the bearing 3 downward in the rotation center axis line 10 and applies a constant preload to the bearings 3 and 4, thereby improving the rotation accuracy.

The cylindrical portion 34 of the bracket 2 has three through holes 9 penetrating from the outside of the spindle motor (that is, from the bottom of the drawing to the inside of the spindle motor (that is, the upper direction of the drawing)).
19 and 29 are drilled. These through holes 9, 1
The reference numerals 9 and 29 are arranged on the bracket 2 in a rotationally symmetrical manner of 120 degrees (with respect to the rotation center axis 10) and are substantially bored in the rotation center axis 10 direction. Through hole 9,
19 and 29 are effective holes in the portion of the cylindrical portion 34 of the bracket 2 and are defined in the space from the outer opening end portion 45 to the inner opening end portion 11. In the case of this embodiment, FIG.
As will be understood from the above, the upper ends of the through holes 9, 19, 29 are defined by the cylindrical portion 34 of the bracket and the stator core 90 of the armature 24. That is, in the illustrated spindle motor, the stator core 90 has, as shown in FIG. 5, an annular base portion 91 and teeth portions 24a to 24f protruding radially outward from the annular base portion 91, and six teeth portions 24a to 24a. 24f are provided on the annular base 91 at substantially equal intervals in the circumferential direction. Further, in connection with the provision of the six teeth portions 24a to 24f, the inner peripheral edge portion of the annular base portion 91 is further divided into six semicircular shapes at substantially equal intervals in the circumferential direction. Notches 92 to 97 are formed. The six notches 92 to 97 are arranged substantially in the center in the circumferential direction of the adjacent teeth portions 24a to 24f, respectively. By providing the notches 92 to 97, the magnetic balance of the armature 24 is improved. Can be kept. In the example, 3 out of 6 notches 9
2, 94, 96 (3 spaced substantially 120 degrees apart
The individual pieces act as notches for fixing the armature 24 to the cylindrical portion 34 (these notches cooperate with the notches provided at the upper end of the cylindrical portion 34 to form a hole having a circular cross section). The fixing screws are screwed to the cylindrical portion 34 through these holes), and the remaining three screws 93, 95 and 97 (three screws substantially 120 degrees apart) will be described later. Acting as notches for inserting the insertion member 50 to be inserted therein (the notches cooperate with the notches provided at the upper end of the cylindrical portion 34 to define the through holes 9, 19, 29 having a circular cross section). Then, as will be described later, the insertion member 50 is inserted). When the annular base 91 of the stator core 90 has a large width (width in the radial direction), an insertion hole may be formed instead of the notch. In the embodiment, the notch 25 is formed instead of the through hole at the fitting small diameter portion 33.
The portion of the rotor hub 5 facing the inner opening end 11 faces the inner bottom surface 12 (that is, the lower end surface of the hub 15). The inner bottom surface portion 12 is a surface substantially perpendicular to the longitudinal axis of the through holes 9, 19, 29.

Next, with reference to FIGS. 6 to 8, a method of attaching and fixing the polygon mirror 6 to the rotor hub 5 using the spindle motor described in FIGS. 1 to 4 will be described in detail. Note that the same numbers are given to the same parts and members that have already been described and used. The member 50 shown in FIG. 7 is an insertion member used when the polygonal mirror 6 is attached and fixed to the rotor hub 5. The insertion member 50 is integrally formed of iron,
It has an annular body portion 53 and three insertion portions 51 which are vertically provided on the circumference of the body portion 53 at equal intervals of 120 degrees. The shape of the insertion portion 51 is, as already understood, the through holes 9 and 1 of the spindle motor used in FIGS. 1 to 5.
It is formed corresponding to 9 and 29. That is, the through hole 9,
The outer diameter dimension of the insertion portion 51 is defined in accordance with the opening shapes of 19 and 29. Further, the insertion portion 51 is formed with a sufficient size corresponding to the length of the through holes 9, 19, 29.

When the polygon mirror 6 is attached and fixed to the rotor hub 5, first, as shown in FIG.
The polygon mirror 6 is held from the upper side to the lower side in the drawing, and then the clamp member 7 is similarly placed from the upper side to the lower side.
Next, as shown in FIG. 8, the insertion portion 51 of the insertion member 50 is inserted into the corresponding through holes 9, 1 from the bottom surface (lower end in the drawing) of the spindle motor toward the inside (upward direction in the drawing).
Insert to 9, 29. At this time, the three notches 25 are
The distal end portions 52 of the insertion portions 51 serve as guides for easily inserting the distal end portions 52 into the outer open end portions 45 of the cylindrical portion 34.

In FIG. 8, the take-over insertion member 50 is inserted inward (upward in the drawing) of the spindle motor until the tip portion 52 thereof comes into contact with the inner bottom surface portion 12 through the notches 93, 95, 97 of the stator core 90. , Hold it at the required pressing force F. Next, the mounting screw 8 is screwed into the mounting hole 26 of the rotor hub 5 via the clamp member 7. At this time, the pressing force P by the mounting screw 8 acts downward in the direction of the rotation center axis 10. Then, the pressing force F of the insertion member 50
And the pressing force P by the mounting screw 8 act as mutually opposing stresses in the direction of the rotation center axis 10 and substantially no unbalanced stress acts on the rotor hub 5. Therefore, the bearings 3 and 4 that rotatably support the rotor hub 5 are not damaged by this stress.

In order to cancel these two pressing forces F and P more effectively, the through holes 9 provided in the bracket 2,
19, 29 and mounting screw holes 26 in the rotor hub 5,
26, it is best that their positional relationship is substantially the same in the radial direction of the rotation center axis line 10, but there is no problem even if they are slightly deviated as in the illustrated example. In addition, since the through holes 9, 19, 29 are formed substantially in the direction of the rotation center axis 10, even if the insertion member 51 has a plurality of insertion portions 51, the insertion holes can be easily inserted.

As described above, one of the spindle motors according to the present invention
Although the embodiments have been described, the present invention is not limited to such embodiments, and various changes and modifications can be made without departing from the scope of the present invention. In the spindle motor of this embodiment, three through holes 9 are provided in the bracket 2, but it can be designed arbitrarily according to the shape of the spindle motor, the number of screwing points of the mounting screws 8, and the like. Further, the hole shape of the through hole 9 and the cross-sectional shape of the insertion member corresponding thereto can be freely selected.

In the spindle motor of the present invention, the polygonal mirror for optical deflection is used as the rotation load member. However, in addition to this embodiment, a recording medium having a thin disk shape such as an optical / magnetic disk can be applied. Also in this case, in addition to the use of the clamp member 7 having the above-described shape, the outer peripheral side of the annular protruding portion 44 of the rotor hub 5 shown in FIG. A clamp member may be used in which the inner peripheral wall of the member is formed as a male screw over the entire circumference so that these members are screwed and the recording medium is integrally mounted and fixed.

In addition, as the bearing member, the bearing is used in the spindle motor of this embodiment, but a bearing such as a dynamic pressure bearing in which a fluid is interposed may be used. Needless to say, the number of bearing members used and the size thereof can be freely designed.

[0024]

As described above in detail, since the spindle motor of the present invention has the above-mentioned structure, when the rotary load member is attached to the rotor hub by the clamp member, it is used as a bearing member for rotatably supporting the rotor hub. It can be mounted and fixed without damaging it. Therefore, noise or vibration is not generated due to the damage of the bearing member, and the deterioration of the deflection accuracy (so-called NRRO) due to non-repetition due to minute deformation of the bearing member is not caused. Therefore, it is possible to obtain a spindle motor suitable for the above-mentioned device which requires high reliability and rotation accuracy.

[Brief description of drawings]

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

FIG. 2 is a bottom view of the spindle motor shown in FIG.

FIG. 3 is a sectional view showing a state of a single motor of the spindle motor shown in FIG.

FIG. 4 is a plan view of the spindle motor shown in FIG.

5 is a plan view showing a stator core of the spindle motor shown in FIG. 1. FIG.

6 is a cross-sectional view showing a state in which a rotary load member is attached and fixed to the spindle motor shown in FIG.

FIG. 7 is a perspective view showing an example of an insertion member.

8 is a sectional view showing a state in which a rotary load member is attached and fixed to the spindle motor shown in FIG.

FIG. 9 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

 1 Shaft (Stationary Member) 2 Bracket (Stationary Member) 3, 4 Bearing (Bearing Member) 5 Rotor Hub 6 Rotating Polyhedral Mirror (Rotating Load Member) 7 Clamping Member 8 Mounting Screws 9, 19, 29 Through Hole 14 Annular Magnet 24 Armature 50 Insert member

Claims (1)

[Claims] 1. A stationary member, a bearing member mounted on the stationary member, a rotor hub supported rotatably relative to the stationary member via the bearing member, and a rotor magnet mounted on the rotor hub. A spindle motor having an armature attached to the stationary member facing the rotor magnet, wherein a rotation load member is attached and fixed to the rotor hub by a clamp member, and the stationary member includes:
A through hole is formed so as to penetrate from the outside of the stationary member inward along the center axis of rotation, and the inner open end of the stationary member faces the bottom surface of the rotor hub, and the armature corresponds to the through hole. A notch or insertion hole is formed, when inserting and fixing the rotation load member to the rotor hub, insert the insertion member through the through hole and the notch or insertion hole,
A spindle motor, characterized in that the distal end portion of the insertion member is brought into contact with the bottom surface portion of the rotor hub, and the rotary load member is attached to the rotor hub while the rotor hub is held stationary.