JP2951295B2 - 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 for rotating a recording disk.

[0002]

2. Description of the Related Art Generally, a spindle motor is mounted on a mounting member mounted on an apparatus frame, a rotating member rotatably supported on the mounting member via a bearing member, and an inner peripheral surface of the rotating member. And a stator mounted on a mounting member facing the rotor magnet, and a recording disk such as a magnetic disk is mounted on a rotating member. In a fixed shaft type motor, a shaft member is fixed to a mounting member, and a rotating member is rotatably mounted on the shaft member via a bearing member.

[0003]

However, this kind of spindle motor has the following problems to be solved. That is, the bearing member is composed of an inner ring member, an outer ring member and a spherical member interposed between them,
In connection with such a configuration of the bearing member, it is difficult to reduce the size of the motor, and it is difficult to obtain sufficient rotational accuracy.

In this type of spindle motor, a magnetic seal mechanism or a labyrinth seal mechanism is employed to prevent grease or the like scattered from a bearing member from adhering to the surface of a recording disk. However, the configuration of the motor itself becomes complicated in connection with the magnetic seal mechanism or the labyrinth seal mechanism, and the manufacturing cost also increases.

An object of the present invention is to provide a spindle motor which can obtain sufficient rotation accuracy with a simple structure and is particularly effective for downsizing the motor.

[0006]

Means for Solving the Problems In order to achieve the above object, the present invention provides a mounting member, a shaft member having one end fixed to the mounting member, and a shaft member disposed outside the shaft member. comprising a rotating member relative to the member which is rotatable relative, a rotor magnet attached to the pivoting member, and a stator disposed opposite to the rotor magnet, a shaft
The stator is directly mounted on one end of the member, a pair of inner annular grooves are provided on the outer peripheral surface of the other end of the shaft member , and the inner diameter of one end of the rotating member is the other end. Than the inside diameter of
Is also large, and the rotor
On the inner peripheral surface at the other end of the rotating member , a pair of outer annular grooves are provided corresponding to the pair of inner annular grooves, and the pair of inner annular grooves and the pair of outer annular grooves are provided. The annular grooves respectively cooperate with each other to define a pair of spherical housing spaces located at an interval in the axial direction of the shaft member, and each of the pair of spherical housing spaces includes a plurality of spherical members. Are disposed rotatably and movably along the corresponding ball housing space.

[0007]

According to the present invention, the inner annular groove is provided directly on the outer peripheral surface of the shaft member fixed to the mounting member, and is directly provided on the inner peripheral surface of the rotating member which is rotatable relative to the shaft member. An outer annular groove is provided, and a plurality of spherical portions are interposed between the inner annular groove and the outer annular groove, and the rotating member is rotatably supported by the shaft member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show a first embodiment of a spindle motor according to the present invention. 1 and 2, the illustrated spindle motor includes a mounting member 2, a shaft member 4,
And a rotating member 6. The attachment member 2 can be formed of aluminum or the like, and is attached to an apparatus frame of a driving device (not shown). The shaft member 4 is formed of an elongated cylindrical rod, and one end (lower end) thereof is fixed to the mounting member 2 by press fitting or the like. This shaft member 4
Extends substantially vertically upward from the mounting member 2, and a rotating member 6 is rotatably supported at the other end.

In the first embodiment, a pair of inner annular grooves 8a are formed on the outer peripheral surface of the other end of the shaft member 4 at an axial interval.
And 8b are formed. The inner annular grooves 8a and 8b have a substantially semicircular cross section, and extend in parallel with each other around the entire circumference of the shaft member 4. The rotating member 6 has a substantially cylindrical shape, and is provided at one end thereof with a flange portion 10 projecting outward in the radial direction. The inner diameter of one end (lower end) of the rotating member 6 is larger than the inner diameter of the other end (upper end). A pair of outer annular grooves 12a and 12b are formed on the inner peripheral surface of the other end of the rotating member 6 at intervals in the axial direction corresponding to the pair of inner annular grooves 8a and 8b of the shaft member 4. ing. The outer annular grooves 12a and 12b also have a substantially semicircular cross-sectional shape, and extend in parallel with each other around the entire inner peripheral surface of the rotating member 6. Such a pair of outer annular grooves 12a and 12b
Defines a pair of spherical accommodation spaces having a substantially circular cross section in cooperation with the inner annular grooves 8a and 8b of the shaft member 4, and a plurality of spherical members 14 are rotatably provided in the pair of spherical accommodation spaces, respectively. It is movably arranged along the corresponding ball accommodation space. Therefore, the rotating member 6 is rotatably supported via these spherical members 14. In a specific example, the rotating member 6 is formed of a magnetic material such as copper, and functions as a hub member on the outer peripheral surface of which a recording disk such as a magnetic disk is mounted.

In the first embodiment, the stator 16 and the rotor magnet 18 are arranged in a relatively large space defined at one end of the rotating member 6. The stator 16 includes a stator core 20 formed by laminating plate-shaped members. The stator core 20 is fixed to the outer peripheral surface of one end of the shaft member 4 by means such as press fitting. An armature coil 21 is wound around the stator core 20 as required. The rotor magnet 18 is formed of an annular permanent magnet, and is fixed to the inner peripheral surface of one end of the rotating member 6 with an adhesive or the like, facing the stator 16. With this configuration, the rotating member 6 is rotated in a predetermined direction by supplying a current to the armature coil 21 as required.

In the first embodiment, outside the pair of ball housing spaces, that is, outside one ball housing space defined by the inner annular groove 8a and the outer annular groove 12a (the lower side in FIGS. 1 and 2). A seal member 22 is provided outside (the upper side in FIGS. 1 and 2) of the other spherical housing space defined by the inner annular groove 8b and the outer annular groove 12b. The seal member 22 is annular and can be formed, for example, from synthetic rubber. The outer peripheral edge of the seal member 22 is somewhat thicker, and the outer peripheral edge is mounted in an annular groove formed in the inner peripheral portion of the rotating member 6. The inner peripheral edge of the seal member 22 is close to the outer peripheral surface of the shaft member 4 to prevent grease or the like filled in the ball housing space from scattering to the outside. The inner peripheral edge of the seal member 22 may relatively weakly contact the outer peripheral surface of the shaft member 4. If scattering of grease or the like does not pose a problem, the seal member 22 can be omitted.

The shaft member 4 and the rotating member 6 can be assembled, for example, as follows. That is, the rotating member 6 is heated by a high frequency heater (not shown) or the like to expand its inner diameter, and in this state, the rotating member 6 is attached to the shaft 4 via a plurality of spherical members 14. Assemble as follows. Then, the interval between the inner annular grooves 8a and 8b and the outer annular grooves 12a and 12b
Are slightly shifted from each other, a predetermined preload can be applied between the shaft member 4 and the rotating member 6 when combined as described above. Further, by holding the plurality of spherical members 14 accommodated in the respective ball accommodating spaces at substantially equal intervals by the ball holding member 24, the assembling of the spherical members 14 becomes easy, and the rotating member 6 The rotation of becomes smooth.

In the first embodiment, when the shaft member 4, the plurality of spherical members 14, and the rotating member 6 are formed of the same material (for example, copper), the expansion coefficient is constant.
Even when the temperature changes, the gap between the members does not substantially change, and stable rotation can be obtained even when the temperature changes.

In the first embodiment, for example, the shaft member 4, the plurality of spherical members 14, and the rotating member 6 can be manufactured as one component. When I made it like this,
A rotor magnet 18 is fixed to the inner peripheral surface of the rotating member 6,
Further, by fixing the stator 16 to the shaft member 4 and then fixing one end of the shaft member 4 to the mounting member 2 by press fitting or the like, the motor as shown in FIG. 1 is completed.

As can be easily understood from FIG. 1, the motor of the first embodiment has a smaller number of constituent parts than the conventional one.
The assembling work is easy, and downsizing of the motor is easily achieved. In addition, since the number of components is small, accumulation of dimensional errors of the components is small, and high rotational accuracy is obtained.

FIGS. 3 and 4 show a second embodiment of the spindle motor according to the present invention. In the second embodiment, the rotation member functioning as a hub member on which a recording disk is mounted is improved. In the second embodiment, the same members as those in the first embodiment will be described with the same reference numerals.

In FIG. 3 and FIG. 4, the illustrated rotating member 6 'includes a substantially hollow cylindrical rotating body 40 and the rotating body 40.
And an annular member 42 to be mounted on it. The inside diameter of one end of the rotating main body 40 is larger than the inside diameter of the other end, and the stator 16 and the rotor magnet 18 are arranged in the space of this one end similarly to the first embodiment. A step 44 (FIG. 4) is formed on the inner peripheral surface of the other end of the rotating main body 40, and the inner diameter of the other end is enlarged. One of the outer annular grooves 1 corresponding to the inner annular groove 8 a formed in the shaft member 4 is provided in the rotation body 40 at an inner portion of the step portion 44.
2a are formed, and the inner annular groove 8a and the outer annular groove 12a cooperate with each other to define a spherical housing space having a substantially circular cross section. The annular member 42 is attached to the enlarged diameter portion 46 through an opening defined in the other end surface of the rotating main body 40 as described later. The inner peripheral surface of the annular member 42 is provided with a concave portion whose upper portion extends radially outward in an arc shape and whose lower portion extends linearly downward. This recess functions as the other outer annular groove 12b ', and cooperates with the inner annular groove 8b of the shaft member 4 to define the other spherical accommodation space. It should be noted that, contrary to the above, one spherical accommodation space may be defined by the inner annular groove 8a of the shaft member 4 and the outer annular groove 12a of the annular member 42.

As in the first embodiment, a plurality of spherical members 14 are provided in the pair of spherical housing spaces defined by the inner annular grooves 8a and 8b and the outer annular grooves 12a and 12b '.
And the rotating member 6 ′ is rotatably supported via these spherical members 14. It is desirable that the spherical member 14 be held by the ball holding member 24 as described above.

The assembly of the rotating member 6 'can be performed, for example, as follows. First, the rotating main body 40 is heated by a high-frequency heater (not shown) or the like to expand its inner diameter, and in this state, the rotating main body 40 is attached to the shaft member 4 via the plurality of spherical members 14. Assemble as follows. Next, the plurality of spherical members 14 are positioned in the remaining inner annular groove 8b, and thereafter, the annular member 42 is inserted in the direction indicated by the arrow 48 through the opening at the other end surface of the rotating main body 40 to rotate the rotating main body 4.
0 is fixed to the inner peripheral surface of the large diameter portion 46. The fixing of the annular member 42 can be performed, for example, with an adhesive or the like in a state where a predetermined load is applied. Means such as shrink fit may be used instead of the adhesive.

The other structure of the second embodiment is substantially the same as that of the first embodiment shown in FIGS. This second
In this embodiment, the configuration is somewhat complicated due to the presence of the annular member 42, but the same effect as that of the first embodiment is achieved from the viewpoint of miniaturization of the whole motor.

FIG. 5 shows a modification of the second embodiment. In this modification, a preload applying mechanism for applying a preload to a spherical member is modified. 5, the annular member 42 is mounted on the inner peripheral surface of the enlarged diameter portion 46 of the rotating main body 40 so as to be movable in the axial direction (vertical direction in FIG. 5).
An inner annular groove 8 of the shaft member 4 is provided on an inner peripheral surface of the annular member 42.
outer annular groove 12b "which defines a ball receiving space in cooperation with b.
The outer annular groove 12b ″ and the inner annular groove 8b are formed.
A plurality of spherical members 14 are interposed between them.

The preload applying mechanism according to the modification includes an urging means 52 acting on the annular member 42. The illustrated urging means 5
2 is composed of a pair of disc springs 54 and one disc spring 54
Is in contact with the annular member 42 and the other disc spring 54
Is in contact with a locking member 56 locked to the rotating main body 40. Therefore, the biasing means 52 elastically biases the annular member 42 downward in FIG. 5 and applies a predetermined preload between the rotating member 6 ′ and the shaft member 4. Other configurations in the modified example are substantially the same as those in the second embodiment shown in FIGS.

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

Although various embodiments of the spindle motor according to the present invention have been described above, the present invention is not limited to these embodiments, and various changes and modifications can be made without departing from the scope of the present invention. It is possible.

[0031]

Since the present invention is configured as described above, the following effects can be obtained. A plurality of spherical members are rotatably and movably disposed between an inner annular groove on the outer peripheral surface of the shaft member fixed to the mounting member and an outer annular groove on the inner peripheral surface of the rotating member. On the other hand, since the rotating member is rotatably supported, the inner ring member and the outer ring member of the conventional bearing member are not required, the configuration is simplified, and it is possible to greatly contribute to downsizing of the motor. Since the conventional inner ring member and outer ring member are not interposed, sufficient dimensional accuracy and rotational accuracy can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a sectional view of a main part of the spindle motor of FIG. 1;

FIG. 3 is a simplified sectional view showing a second embodiment of the spindle motor according to the present invention.

FIG. 4 is a sectional view of a main part of the spindle motor of FIG. 3;

FIG. 5 is an essential part cross-sectional view in which a part of the spindle motor of the second embodiment is improved.

[Explanation of symbols]

 2 Mounting member 4 Shaft member 6, 6 'Rotating member 16 Stator 18 Rotor magnet 8a, 8b Inner annular groove 12a, 12b, 12b', 12b "Outer annular groove 14 Spherical member

Claims (1)

(57) [Claims] 1. A mounting member,One endFixed to the mounting member
And a shaft member disposed outside the shaft member.
A rotating member rotatable relative to the rotating member;
A rotor magnet attached to the material;
And a stator disposed opposite to the slot.The stator is directly mounted on one end side of the shaft member,  The shaft memberThe other endA pair of inner annular grooves are provided on the outer peripheral surface of
Kere,The inside diameter of one end of the rotating member is larger than the inside diameter of the other end.
The inner surface of one end of the rotating member is
Is installed, The rotating memberThe other endOn the inner surface of
A pair of outer annular grooves are provided corresponding to the pair of inner annular grooves.
The pair of inner annular grooves and the pair of outer annular grooves are respectively
Cooperating with each other, they are spaced apart in the axial direction of the shaft member.
A pair of spherical housing spaces to be placed, and a plurality of spherical members are respectively rotated in the pair of spherical housing spaces.
Arranged freely and freely along the corresponding ball storage space
A spindle motor.