JPH079250Y2 - Spindle motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a spindle motor for driving a recording disk such as a magneto-optical disk.

[Prior Art] For example, a spindle motor that rotationally drives a recording disk such as an optical disk includes a bracket and a rotor that is rotatably supported by the bracket, and a stator and a rotor magnet that are driving means are arranged inside the motor. ing. Further, the rotor is provided with a clamp member for holding the disc, and a clamp magnet for magnetically attracting and holding the disc is attached to the clamp member.

As the spindle motor, a multi-phase DC brushless motor is usually adopted, and in order to generate a commutation signal for exciting the stator, magnetic detection means (sensor) such as a Hall element for detecting the rotational position of the rotor magnet is mounted. . Further, in such a spindle motor, the rotation position of the disk is detected and the rotation control of the motor is also performed. Therefore, in addition to the above members, the spindle motor includes, for example, a magnet for index detection for detecting a rotational position, or a magnet for FG (Frequency Generator) for detecting a rotation speed for performing rotation control. Are mounted on the bracket, and together with these, magnetic detection means for detecting signals are arranged on the bracket.

[Problems to be Solved by the Invention] Recently, along with the demand for miniaturization of disk devices, it has become necessary to reduce the spindle motor accordingly. However, if the spindle motor is downsized, the internal space will be overwhelmed. That is, reducing the size of the drive means such as the stator and rotor magnet inside the spindle motor means reducing the magnetic space, and as a result, the characteristics required for the motor are reduced. In addition to rotor rotation detection, index detection magnets and FG
Providing a magnet and these magnetism detecting means inside the motor becomes more and more difficult in order to secure a necessary space. Furthermore, if the inside of the motor becomes dense, these magnets and detection means tend to magnetically interfere with each other, and stable magnetic pole detection cannot be performed.
Stable operation cannot be obtained either.

The present invention has been made in view of the above facts, and an object of the present invention is to provide a spindle motor capable of easily detecting the rotation of the motor and achieving stable operation while achieving downsizing of the motor. Is to provide.

[Means for Solving the Problems] A spindle motor according to the present invention is rotatably supported by a bracket including a flange portion and a cylindrical portion provided orthogonal to the flange portion, and a bearing provided in the cylindrical portion. Shaft member, a rotor provided on one end of the shaft member, and a rotor magnet provided on the rotor,
A stator provided on the bracket facing the rotor magnet, a clamp member provided on the other end of the shaft member, and a clamp provided on the clamp member for magnetically attracting and holding a recording disk. A spindle motor including a magnet; the clamp member is formed of a non-magnetic material, and is connected to the flange portion of the bracket by folding back from one surface of the flange portion to the other surface. A flexible circuit board is provided, and one side of the flange portion of the flexible circuit board faces the bottom wall of the clamp member, and detects the magnetic pole of the clamp magnet through the bottom wall. Magnetic detection means is mounted on the other surface side of the flange portion of the flexible circuit board. Tsu collected by opposed, second magnetic detection means for detecting the magnetic poles of the rotor magnet in which is mounted.

[Operation] According to the spindle motor of the present invention, the flange portion of the bracket is provided with the flexible circuit board which is folded back and communicates with both surfaces of the flange portion, and the first magnetic detection is provided on one surface of the flexible circuit board. Means have been implemented. The first magnetic detecting means is positioned so as to face the clamp member, and the clamp member is made of a non-magnetic material that transmits magnetism. Therefore, the magnetic force from the clamp magnet passes through the clamp member and reaches the first magnetic detection means, and the first magnetic detection means can easily detect the magnetic pole of the clamp magnet.

Also, on the other surface of the flexible circuit board of the flange part,
Second magnetic detection means is mounted, and the second magnetic detection means is positioned so as to face the rotor magnet. Therefore, the magnetic force from the rotor magnet reaches the second magnetic detection means, and the second magnetic detection means can easily detect the magnetic pole of the rotor magnet.

Further, since the flexible circuit board is arranged so as to be folded back on both sides of the flange portion, the circuit configuration itself including the first detection means and the second detection means does not take up space and wiring is omitted, resulting in a simple configuration. Moreover, since the respective magnetism detecting means are positioned so as to face each other on the opposite side of the flange portion, magnetic mutual interference does not occur due to the presence of the flange portion, and stable operation can be obtained.

[Embodiment] An embodiment of a spindle motor according to the present invention will be described below with reference to the drawings. 1 and 2 show, for example, a spindle motor for rotationally driving an optical disk, FIG. 1 is a plan view seen from the top to the bottom, and FIG. 2 is a view taken along the line A--O--B in FIG. FIG. In addition, in FIG. 1, a part of the bracket shown in FIG. 2 is not shown.

1 and 2, the bracket 3 mounted and fixed to a drive unit (not shown) is composed of a flat plate-shaped flange portion 21 and a cylindrical portion 17. Cylindrical part
17 is provided orthogonally to the flange portion 21, and these are integrally formed. A pair of bearings 2, 2 are mounted on the inner peripheral portion of the cylindrical portion 17, and the shaft 1 is rotatably supported via the bearings 2, 2. The portions 11, 11 provided on the shaft 1 are circumferential grooves, and are accumulating grooves for an adhesive for fixing the bearings 2, 2 by adhesion. Further, the member 16 is an elastic member such as a coil spring, which preloads the bearings 2, 2 in the axial direction, thereby preventing the shaft 1 rotatably supported from rattling.

A bowl-shaped rotor 7 is fixed to the lower end of the shaft 1 shown in FIG.
A rotor magnet 5 is annularly provided inside the rotor 7 along the inner peripheral wall thereof. A stator 4 is provided on the bracket 3 side so as to face the rotor magnet 5 in the radial direction. The stator 4 is configured by winding an armature coil around a stator core, and the inner peripheral portion of the stator 4 is externally fitted and fixed to the cylindrical portion 17 of the bracket 3.

On the other hand, a shallow dish-shaped clamp member 18 is fixed to the upper end of FIG. 2, which is the other end of the shaft 1, by opening upward. The clamp member 18 is formed of a non-magnetic material such as an aluminum alloy. The clamp member 18 is provided with a clamp magnet 8 for magnetically attracting and holding an optical disk (not shown).

Therefore, the rotor 7 and the clamp member 18 are fixed at both end portions of the shaft 1, and the flange portion 21 (of the bracket 3) is positioned and arranged between the rotor 7 and the clamp member 18.

A flexible circuit board 15 is attached to the flange portion 21. The flexible circuit board 15 has the upper and lower surfaces of the flange portion 21 and one circuit board folded and attached to both sides. That is, flexible circuit board
The flange portion 15 is bent in a U-shape from the upper right side to the lower side in FIG. 2 of the flange portion 21, and is further provided from the lower side of the flange portion 21 to the lead-out end on the left side of the drawing.

The magnetic sensor 14 such as a Hall element is mounted on the flexible circuit board 15 attached to the upper side of the flange portion 21 in the drawing, that is, the surface side corresponding to the clamp member 18. The magnetic sensor 14 is positioned so as to approach the bottom wall 6b of the clamp member 18 with a slight gap, and detects the magnetic pole of the clamp magnet 8 described later. Also,
A magnetic sensor 13 such as a Hall element is also mounted on the lower side of the flange portion 21 of the flexible circuit board 15 in the figure, that is, on the surface side facing the rotor 7 side. The magnetic sensor 13 is arranged so as to face the upper end of the rotor magnet 5 with a slight gap, and detects the magnetic pole of the rotor magnet 5. The magnetic sensor 13 obtains a commutation signal for energizing the armature coil of the stator 4 by detecting the magnetic pole of the rotor magnet 5.

Further, on the flexible circuit board 15, although not shown, the coil wire drawn from the armature coil of the stator 4 is
It is electrically connected to a predetermined land by soldering or the like.

As described above, in the spindle motor of this embodiment, the rotor 7 and the clamp member 18 face each other on both sides of the flange portion 21.
Are positioned and they are fixed at both ends of the shaft 1. And each is a flange part facing
It is arranged in close proximity to the magnetic sensors 14 and 13 on the flexible circuit board 15 which is provided by being folded back on both sides attached to 21. Therefore, the circuit configuration itself including the magnetic sensors 14 and 13 is simplified, space is saved, and wiring is omitted. Further, due to the presence of the flange portion 21, magnetic mutual interference does not occur.

The clamp magnet 8 provided on the clamp member 18 is
Twelve approximately fan-shaped segment magnets as shown
The material is, for example, ferrite. The clamp member 18 is provided with a recess 22 having a predetermined size and shape so that twelve segment magnets 8c are radially arranged. In this embodiment,
The recesses 22 are provided in the bottom wall 6b of the clamp member 18 at predetermined angular intervals in the circumferential direction, and their axial depths are set to be slightly smaller than the thickness dimension of the segment magnet 8c. There is. A partition wall 6c is formed between the recesses 22 of the clamp member 18. Therefore, each segment magnet 8c is positioned with respect to the clamp member without contacting each other by the partition wall 6c, and most of each segment magnet 8c is embedded in the bottom wall 6b of the recess 22. And only their upper ends appear in the clamp member 18 with some protrusion.

Therefore, the thickness dimension (axial dimension) of the clamp magnet 8 is offset by the embedded amount with respect to the thickness dimension of the clamp member 18, so that the thickness dimension of the clamp member 18 is substantially reduced. can do. Moreover, since the partition wall 6c serves as a reinforcing rib of the clamp member 18, the clamp member 18 can maintain the required rigidity.

As is clear from the figure, in the clamp magnet 8, each of the segment magnets 8c constituting the clamp magnet 8 is monopolarly magnetized with an N pole and an S pole in the axial direction, that is, in the vertical direction in FIG. Therefore, each segment magnet 8c
Is easier to magnetize than the case of multi-pole magnetization, and saturation magnetization is possible. Therefore, the clamping force, which is magnetic attraction, can be increased. In the illustrated example, the segment magnet 8c has N poles and S poles alternately arranged in the circumferential direction, but the clamping force can be adjusted by appropriately changing these arrangements.

The magnetic sensor 14 such as a Hall element has its magnetic detection portion (upper end in the drawing) arranged to face the bottom wall 6b of the clamp member 18 with a slight gap. Since the clamp member 18 is made of a non-magnetic material, the magnetic sensor 14 can easily detect the magnetic pole of the clamp magnet 8. In addition, the clamp magnet 8 is embedded in the clamp member 18 so that the magnetic sensor 14 can easily detect its magnetic pole. As a result, the clamp magnet 8 and the magnetic sensor 14 can be brought as close to each other as possible, and the magnetic sensor 14 can easily detect the magnetic pole of the clamp magnet 8 even though the clamp member 18 is interposed. it can.

Clamp magnet 8 is 12 segment magnets
8c has N poles and S poles arranged alternately.
14 can detect 12 magnetic poles by one rotation of the motor. Since the segment magnets are used, the arrangement of the magnetic poles can be freely set. For example, of the 12 segment magnets 8c shown in the figure, only one on one side is N
If a pole is provided and the remaining 11 poles are S poles, it is possible to detect the index signal, which outputs one signal per one rotation of the motor.

[Advantages of the Invention] Since the present invention is configured as described above, it has the following effects. That is, the flange portion 21 of the bracket 3 is provided with the flexible circuit board 15 which is folded back and communicates with both surfaces of the flange portion 21, and one surface of the flexible circuit board 15 is provided with a magnetic field which is a first magnetic detecting means. The sensor 14 is mounted. The magnetic sensor 14 is positioned so as to face the clamp member 18, and the clamp member 18 is made of a non-magnetic material such as an aluminum alloy that transmits magnetism. Therefore, the magnetic force from the clamp magnet 8 reaches the magnetic sensor 14 through the bottom wall 6b of the clamp member 18, and the magnetic sensor 14 can easily detect the magnetic pole of the clamp magnet 8.

On the other surface of the flexible circuit board 15, a magnetic sensor 13 which is a second magnetic detecting means is mounted, and the magnetic sensor 13 is positioned so as to face the rotor magnet 5. Therefore, the magnetic force from the rotor magnet 5 reaches the magnetic sensor 13, and the magnetic sensor 13 can easily detect the magnetic pole of the rotor magnet 5.

Further, since the flexible circuit board 15 is arranged so as to be folded back on both sides of the flange portion 21, the circuit configuration itself including the first and second magnetic sensors 14 and 13 does not occupy space, and wiring is omitted, which is simple. It becomes a composition. Further, facing the opposite side of the flange portion 21, each magnetic sensor 1
Since 4, 13 are positioned, magnetic mutual interference does not occur due to the presence of the flange portion 21, and stable operation can be obtained.

In this way, the inside of the motor can be simplified, and the overall size can be reduced. Thus, a spindle motor can be obtained which can easily detect the rotation of the motor and can obtain stable operation.

[Brief description of drawings]

FIG. 1 is a plan view of a spindle motor according to the present invention, and FIG.
The drawing is a cross-sectional view taken along the line A-O-B in FIG. 1 ... Shaft, 2 ... Bearing, 3 ... Bracket, 4 ...
… Stator, 5 …… Rotor magnet, 7 …… Rotor,
8 …… Clamp magnet, 13 …… Magnetic sensor, 14 ……
Magnetic sensor, 15 ... Flexible circuit board, 18 ... Clamping member

Claims (1)

[Scope of utility model registration request] 1. A bracket comprising a flange portion and a cylindrical portion provided orthogonally to the flange portion, a shaft member rotatably supported via a bearing provided in the cylindrical portion, and one end of the shaft member. A rotor provided to the rotor, a rotor magnet provided to the rotor, a stator provided to the bracket facing the rotor magnet, and a clamp member provided to the other end of the shaft member, A spindle motor configured to include a clamp magnet that is provided on the clamp member and magnetically attracts and holds a recording disk, wherein the clamp member is formed of a non-magnetic material, and the flange portion of the bracket includes A flexible circuit board that is folded back from one surface of the flange portion to the other surface and is in contact with the other surface. On one surface side of the flange portion of the plate, a first magnetic detection unit that faces the bottom wall of the clamp member and detects the magnetic pole of the clamp magnet through the bottom wall is mounted, and the flexible circuit is provided. A spindle motor, wherein a second magnetic detection means is mounted on the other surface side of the flange portion of the substrate so as to face the rotor magnet and detect a magnetic pole of the rotor magnet.