JP2003180042A - Motor and disk unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor, which is thin and can generate strong torque by suppressing the occurrence of cogging, and to provide a disk device. <P>SOLUTION: The motor comprises an armature having a back yoke 3 made into a cylindrical form and a wound coil 4; and a magnet 6 made into a cylindrical form and having a plurality of magnetic poles magnetized at the cylindrical periphery. The motor and a dirk device are characterized in that the back yoke 3 has a projection 31 projecting from the back yoke 3 to the magnet 6 at the current-switching section of the coil 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor used for rotationally driving a disk-shaped medium, particularly a rotary field type motor, and more particularly to a motor having a characteristic armature structure. is there. The present invention also relates to a disk-shaped medium rotation drive device using these motors, for example, a disk device.

[0002]

2. Description of the Related Art A motor of a rotating field type outer rotor type is generally used as a motor used for rotationally driving a disk-shaped medium because of its smooth rotation and simple structure. Therefore, a conventional technique will be described by taking an outer rotor type motor as an example.

The disc-shaped medium refers to a concentric disc-shaped medium having a central hole, for example, old records (LP, EP).
Etc.), floppy (registered trademark) disk, M
O, MD, PD, CD (ROM, R, RW), DVD
It means a medium such as (ROM, R, RW, RAM). As a general term including these, it will be simply referred to as a disk hereinafter. Further, since it is intended to drive the disc to rotate, it is referred to as a disc regardless of whether or not the disc is housed in a jacket.

First, as a conventional motor technology, a circumferentially opposed motor (radial gap motor) and a surface opposed motor (axial gap motor) will be described below.
FIG. 17 is a perspective view of a conventional circumferentially opposed motor, and FIG. 18 is a sectional view taken along line XX of FIG. 17 is a perspective view of FIG. 17 and FIG.
The configuration of a conventional circumferentially opposed motor will be described with reference to the sectional view of FIG.

Reference numeral 10 denotes a pole, which is a laminated iron core pole 10 formed by laminating a plurality of silicon steel sheets in order to prevent eddy currents. 46 is a coil, and pole 1
It is wound around 0 and a drive current is applied. Reference numeral 61 denotes a magnet, which is arranged so as to face the pole 10.
Reference numeral 13 is a turntable on which a disc is placed and rotated. Reference numeral 21 is a bearing that holds the central axis of the turntable 13. Reference numeral 15 denotes a chucking unit for mounting the disc on the turntable 13, and there is also a chucking unit 16 which determines the center position of the disc by a chucking ball 16 and brings the disc into close contact with the turntable 13.

Next, FIG. 19 is an explanatory view of the rotation operation of FIG. In FIG. 19, the magnet 61 of the circumferentially opposed motor
Is magnetized so that the S pole and the N pole are distributed on the inner circumference side and the outer circumference side, respectively. When a driving current is applied to the coil 46, the pole 10 is magnetized according to the right-handed screw law. In this way, a repulsive force or an attractive force is generated between the magnetic pole of the pole 10 and the magnet 61. Here, by controlling the current flowing through the plurality of coils 46 and the timing thereof, as shown in FIG.
The repulsive force and the attractive force generated during the period are alternately generated and switched to continuously generate a thrust force in a fixed direction to rotate the turntable 13 which is a rotor magnet.

Next, a face-to-face motor will be described as another conventional technique. FIG. 20 is a perspective view of a conventional face-to-face motor,
21 is a sectional view taken along line YY of FIG. 20, and FIG. 22 is FIG.
FIG. 7 is an explanatory diagram of a rotation operation of FIG. In the perspective view of FIG. 20 and the sectional view of FIG. 21, 47 is a coil to which a drive current is applied. Then, after forming the plurality of coils 47 on the printed circuit board, they are coated with an insulating material such as resin to be integrally formed with the coil board 49. A magnet 62 is arranged in parallel with the coil substrate 49.

Reference numeral 51 is a ferromagnetic yoke attached so as to be in close contact with the magnet 62. Reference numeral 34 is a turntable on which a disk is placed and rotationally driven, and 22 is a bearing which holds the central axis of the turntable 34. 15 is a chucking unit, which is a chucking ball 1.
There is also one in which the center position of the disk is determined by 6 and the disk is further brought into close contact with the turntable 34.

Next, the rotating operation of the face-to-face motor will be described with reference to FIG. As mentioned above, the magnet 62 is
It is magnetized so as to be distributed in the circumferential direction so that an S pole and an N pole appear on the upper surface side and the lower surface side, respectively. FIG. 23 is a magnetization distribution map of the magnet of FIG. As shown in FIG. 23, the magnet 62 is magnetized by being divided into a plurality of regions in the circumferential direction. Therefore, as shown in FIG. 21, since the magnet 62 is sandwiched between the turntable 34 and the yoke 51, a magnetic flux is generated in the axial (rotating shaft of the motor) direction. Further, when a drive current is applied to the coil 47, a magnetic flux is generated by the coil current according to the right-handed screw law.

Thus, a repulsive force or an attractive force is generated between the magnetic flux due to the coil current and the magnet 62.
Here, by controlling the current flowing through the plurality of coils 47 and the timing thereof, as shown in FIG. 22, repulsive force and attractive force generated between the magnet 62 and the coil 47 are alternately generated and switched. In the face-to-face motor, the turntable 34, which is a rotor magnet, is continuously rotated to generate thrust in a constant direction. In any of the above-described circumferentially facing and face facing manners, the rotating turntable 34 drives the disk to rotate and functions as a disk device.

[0011]

The conventional motor having the above-mentioned structure has the following problems. In other words, the conventional circumferentially opposed motor has the field N, S
The principle of motor operation is to rotate between the poles and the salient poles of the armature (core) using magnetic attraction or repulsion. That is, the suction and repulsion are repeated during one cycle of the motor. The repetition thereof causes torque fluctuation as it is, resulting in torque unevenness. Regarding this torque unevenness, the torque unevenness portion with respect to the total torque is called cogging. From the above operating principle, it is inevitable that the counter-rotating motor cannot avoid cogging accompanying rotation.
It was usually done.

Further, since the conventional face-to-face motor has a structure in which the yoke, the coil substrate, and the rotor magnet are stacked in the axial direction, there is a limit to making the device thinner. In addition, the arrangement of the coil substrate and the structure of the coil described above is disadvantageous in that a large torque is generated as compared with the motor having the circumferentially opposed structure.

In particular, for a device using a small disc, a motor which is thinner and can generate a strong torque is required in order to take advantage of the small feature. The present invention has been made in order to solve the above problems, and provides a motor that can reduce cogging, is thin, and can generate a strong torque, and a disk device using the motor. To aim.

[0014]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and is an armature yoke formed in a cylindrical shape and an electric machine wound around the cylindrical peripheral surface of the armature yoke. A motor having an armature having an armature coil, and a cylindrical field magnet having a cylindrical peripheral surface magnetized with a plurality of magnetic poles, wherein an armature yoke is provided in a current switching portion of the armature coil. A motor having a convex portion protruding from an armature yoke toward a cylindrical field, and a disk device using the motor.

With the above motor configuration, it is possible to provide a motor and a disk device which are highly efficient in power consumption and have a small change in current consumption with respect to temperature changes and which can be made thin. You can

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The invention described in claims 1 to 4 of the present invention comprises an armature yoke formed in a cylindrical shape and an armature coil wound around the cylindrical peripheral surface of the armature yoke. A motor having an armature and a cylindrical field magnet, which is formed in a cylindrical shape and has a plurality of magnetic poles magnetized on a cylindrical peripheral surface, wherein the armature yoke is a current switching portion of the armature coil. The motor is characterized in that a convex portion that protrudes toward the cylindrical field is formed.

The magnetic flux generated in the armature yoke when a current is applied to the coil wound around the armature yoke is discharged from the convex shape provided on the armature yoke, and the discharged magnetic flux is discharged from the field. By merging with the generated magnetic flux, the magnetic flux is strengthened and a motor that can generate strong torque,
It is possible to provide a motor that can be made thin and a disk device that uses this motor.

The invention according to claims 5 to 13 of the present invention is an armature having an armature yoke formed in a cylindrical shape and an armature coil wound around the cylindrical peripheral surface of the armature yoke. A motor having a cylindrical field which is formed in a cylindrical shape and has a plurality of magnetic poles magnetized on a cylindrical peripheral surface, wherein the armature yoke has a convex portion protruding from the armature yoke toward the cylindrical field. The armature yoke is formed with a concave portion on the back surface of the armature yoke, and the armature coil has two coils wound on both sides of the convex portion, and the winding end on one side and the winding end on the other side are formed. A motor and a disk device, which are connected to form a group of armature coils.

The magnetic flux generated in the armature yoke when a current is applied to the coil wound around the armature yoke is discharged from the convex shape provided on the armature yoke, and the discharged magnetic flux is discharged from the field. By merging with the generated magnetic flux, the magnetic flux is strengthened and a motor that can generate strong torque,
It is possible to provide a motor that can be made thin and a disk device that uses this motor.

The invention according to claim 14 to claim 18 of the present invention is a winding method for winding an armature coil on a cylindrical armature yoke, wherein the armature yoke is an armature yoke. To form a convex portion projecting toward the cylindrical field, the armature coil has two coils wound on both sides of the convex portion in the same direction, and the winding end on one side and the winding end on the other side. Is connected to form a group of armature coils, which is a winding method. According to the present invention, the winding process can be facilitated.

Embodiments of the present invention will be described below with reference to the drawings. The present invention will be described below by taking a spindle motor for driving a disk as an example of a motor type that can effectively utilize the features of the present invention. Needless to say, the examples used for the description do not limit the present invention to the applications of the spindle motor.

(Embodiment 1) FIG. 1 is a perspective view of a motor according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a rotating shaft of the motor. Reference numeral 2 is a bearing for the rotary shaft 1. Reference numeral 3 denotes a back yoke which is arranged concentrically with respect to the rotary shaft 1 and in a direction in which the magnet 6 is made of a magnetic material (in the present embodiment, the outer peripheral portion of the back yoke 3).
In the direction in which the magnet 6 does not exist (in the present embodiment, it is the inner peripheral portion of the back yoke 3,
(Corresponding to the back surface of) and a concave portion 32 are formed in a cylindrical ring shape. A coil 4 is wound around the back yoke 3.

Reference numeral 5 is a yoke, and 6 is a magnet. The magnet 6 holds the magnet 6 by closely adhering to the yoke 5, and the plane in the radial direction functions as a turntable 13. Since the chucking unit 15 and the chucking ball 16 provided on the turntable 13 are the same as those described in the related art, the same names and reference numerals are given and duplicate description is omitted.

The magnet 6 is formed in a cylindrical shape, and has a plurality of poles magnetized in an N / S alternating manner in the circumferential direction of the cylindrical peripheral surface. The magnet 6 and the back yoke 3 around which the coil 4 is wound are arranged concentrically with respect to the rotating shaft 1 with a predetermined gap therebetween. A motor base 8 fixes the bearing 2 and the back yoke 3.

Next, the armature (stator) portion which is a feature of the present invention will be described in detail. FIG. 2 is a plan view of an essential part of FIG. In FIG. 2, the armature portion is composed of the back yoke 3 and the coil 4. First, back yoke 3
Is a high-permeability ferromagnetic material formed of a magnetic material.
Particularly, on the peripheral surface thereof, the convex portion 31 is formed in the direction in which the magnet 6 is present (the outer peripheral portion of the back yoke 3 in the present embodiment), and the direction in which the magnet 6 is not present (the back yoke 3 in the present embodiment). It is formed in a cylindrical ring shape in which a recess 32 is formed on the inner peripheral portion of the. It is a magnetic material that is easy to process and easy to obtain. Generally, carbon steel, electromagnetic steel, and silicon steel are used. The back yoke 3 may have a cylindrical shape. Since an AC-shaped magnetic flux flows through the back yoke 3, a thin plate-shaped ferromagnetic material may be laminated and used for the purpose of reducing eddy current loss. It is also possible to use a sintered material that can be easily molded as the back yoke material in consideration of economical efficiency during mass production. In this case, a ferrite sintered material or the like is preferably used.

Next, the method of winding the coil 4 around the back yoke 3, which is the first feature of the present invention, will be described. FIG. 3 is a diagram for explaining the coil winding method of FIG. Here, for convenience of description, a motor including 18 coils 4 and a magnet 6 having 12 poles will be described.
In FIG. 3, all of the 18 coils 4 are wound in the same A direction with respect to the back yoke 3 to simplify the winding process (for all the coils, the direction opposite to the A direction is set). It is also possible to wind.) Since the coil 4 is the smallest structural unit, it is abbreviated as a unit coil 41 in order to facilitate the later description.

FIG. 4 is a diagram for explaining the coil connection of FIG. 1, and FIG. 5 is a wiring diagram of all the coils of FIG. Two adjacent unit coils 41 connect one winding end and the other winding end. Therefore, the current that has entered from the H direction at the winding start of one unit coil 41 flows from the lower direction to the upper direction of the unit coil 41 in the I direction, and flows from the one winding end to the winding end of the adjacent unit coil 41 in the J direction. Further, wiring is performed so that the unit coil 41 flows from the winding end to the winding start in the K direction from the upper direction to the lower direction and flows out in the L direction from the winding start of the unit coil 41. In this way, the adjacent unit coils 41 are connected to form nine coils. The adjacent unit coils 41 connected to each other are abbreviated as a coil group 42 in order to facilitate the subsequent description.

In FIGS. 2 and 5, these nine coil groups 42 are attached so that the connected central portions thereof straddle the concave portions 32 and the convex portions 31 provided on the back yoke 3, respectively. That is, in FIGS. 4 and 5, the currents flowing through the unit coils 41 flow in opposite directions with the convex portion 31 interposed therebetween. That is, the current switching portion of the coil group is located on the convex portion 31. Further, the unit coil 41 is closely wound so that there is no gap in the winding, and the back yoke 3 is alignedly wound. Therefore, the coil 4 is not arranged in the region of the convex portion 31 and the concave portion 32, and the coil 4 is aligned and wound around the cylindrical portion of the back yoke 3 where the convex portion 31 and the concave portion 32 do not exist.

In FIG. 5, the nine connected coil groups 42 are connected in series at the beginning of winding of the two adjacent (ie, third) coil groups 42. Therefore, the nine coil groups 42 are organized into three parallel circuits in which the three coil groups 42 are connected in series. That is, it becomes a three-phase armature coil. Connect all winding end terminals of each series connection to make COM terminals (indicated by C in the figure), and use a common power supply for all circuits (for example, 0V)
Connect to. The winding start terminal of each series connection is connected to the power source of each of the three phases (indicated by U, V, and W in the figure). The above circuit configuration shown in FIG. 5 is an example for explaining the basic configuration, and the present invention is not limited to the above description. For example, the number of coil groups 42 connected in series is one circuit. However, it may be four or more circuits. Further, the number of parallel circuits is not limited to three, and may be six.

FIG. 6 is a perspective view of a motor having another winding, and FIG. 7 is a view for explaining the connection of adjacent coils in FIG. Further, a coil winding method for simplifying the winding process of the coil 4 will be described. 6 and 7, a coil hook 9 that holds the central portion of the coil is provided on the convex portion 31 of the back yoke 3, and the central portion of the coil is locked to the coil hook 9. Next, the back yoke 3 is rotated so that both ends of the coil 4 are rotated in the B and C directions, respectively.
To wind. That is, the coil central portion is fixed and wound so as to rotate both ends of the coil in the same direction with respect to the back yoke 3. The coils are wound in the same direction, but since the central part of the coil is folded back, the left and right unit coils 41
Will be wound in reverse rotation with respect to the back yoke 3. In this way, nine coils are created. According to the present winding method, the coil 4 corresponds to the coil group 42 described above, and when the coil 4 is divided into ½ from the center, it corresponds to the unit coil 41 described above. That is, the coil 4 is a coil group 43 having a coil central portion, and has unit coils 41 wound in opposite directions to each other.

FIG. 8 is a diagram for explaining the coil current of FIG. When the wound coil group 43 is energized, the current flowing from the P direction flows from the lower direction of the coil to the upper Q direction, flows through the center of the coil in the R direction, and further from the upper direction to the lower S direction. The current flows, and finally the current flows out in the T direction. Each of the nine coil groups 43 is attached such that the coil central portion straddles the concave portion 32 and the convex portion 31 provided on the back yoke 3. Further, the unit coil 41 is closely wound so that there is no gap in the winding, and the back yoke 3 is alignedly wound. Even if the other winding method shown in FIG.
As in FIG. 5, the current flowing through the unit coil 41 is the convex portion 31.
They will flow in the opposite directions across the. That is, the current switching portion of the coil group 43 is located on the convex portion 31.

FIG. 9 is a connection diagram of all the coils shown in FIG. In FIG. 9, the nine connected coil groups 43 are connected in series at the beginning of winding of the two adjacent (that is, the third) coil groups 43. Therefore, the nine coil groups 43 are organized into three parallel circuits in which the three coil groups 43 are connected in series.
That is, it becomes a three-phase armature coil. All the winding end terminals of each series connection are connected to form a COM terminal (indicated by C in the figure), and are connected to a common power supply (for example, 0 V) for all circuits.
The winding start terminal of each series connection is connected to the power source of each of the three phases (indicated by U, V, and W in the figure). In addition,
The above circuit configuration shown in FIG. 9 is an example for explaining the basic configuration, and the present invention is not limited to the above description. For example, the number of coil groups 43 connected in series may be one circuit. However, the number of circuits may be four or more. Further, the number of parallel circuits is not limited to three, and may be six.

Next, the convex portion which is the second feature of the present invention will be described. FIG. 10 is a diagram for explaining the details of the convex portion in FIG. FIG. 10A is a partially enlarged view of the convex portion. In the figure, the thickness of the back yoke 3 is referred to as a yoke thickness t. Further, regarding the convex portion 31, the shoulder portion with the concave portion 32 has shoulder yoke thicknesses a and c, and the thickness between the convex portion 31 and the concave portion 32 is b. Further, the amount of protrusion of the convex portion 31 from the cylindrical peripheral surface portion of the back yoke 3 is defined as the convex portion height h. The gap length between the cylindrical peripheral surface portion of the back yoke 3 and the magnet 6 is g.

First, the yoke thickness t is set so as to secure a sufficient magnetic flux density, prevent eddy current loss, and reduce resistance loss of the coil 4. T to satisfy the former two
Is required to be increased, and t is required to be decreased to satisfy the latter. In the spindle motor of the disk device to which the present invention is applied, the yoke thickness t is 1.2 ≧
By setting t ≧ 2.0 (mm), a motor having a suitable low loss performance could be obtained.

As will be described later in detail in the magnetic circuit, the magnetic flux is formed into a beam shape by the convex portions 31. At the same time, it is necessary to maintain the cross-sectional area of the magnetic circuit similar to that of the cylindrical peripheral surface portion of the back yoke 3 to prevent the occurrence of magnetic saturation. Therefore, it is necessary to maintain the relationship of a, b, and c ≧ t. In particular, it is important to secure the shoulder yoke thicknesses a and c in the process of processing the back yoke 3.

Next, the height h of the convex portion is set by the effect of narrowing the magnetic flux into a beam and the allowable range of cogging. In the spindle motor of the disk device to which the present invention is applied, the height h of the convex portion is set to 0.1 ≧ h ≧
By setting it to 0.5 (mm), it was possible to obtain a motor having the required high torque and low cogging performance.

Further, FIG. 10B is a view for explaining the angle of the convex portion. θ is the convex portion angle, and represents the angle that one convex portion 31 occupies in the front periphery of the back yoke 3. As described above, since the coil 4 is aligned and wound around the cylindrical portion of the back yoke 3 and the unit coil 41 is disposed so as to straddle the convex portion 31, the convex portion 31 is a region where no coil exists. Therefore, the region of the convex portion 31 becomes an important element for forming the magnetic flux in a beam shape. Especially, the turntable diameter is 29m
In the spindle motor for a disk device of m, when the three-phase armature coil is configured by three coil groups and the magnet 6 is configured by 12 poles (see FIG. 13 described later), θ =
It was possible to obtain a motor having the required high torque and low cogging performance at 5 ± 0.5 °. Further, if the number of poles of the magnet 6 is changed to 8 poles or 16 poles and the motor diameter is changed according to the number of poles by changing the coil group configuration to two or four, θ becomes 2 ° and 8 °. Is obtained.
That is, the optimum condition range of 2 ≧ θ ≧ 8 (degrees) is obtained.

Next, in order to control the rotation of the motor, a means for sensing the rotation state (change in magnetic flux during rotation, rotation speed, etc.) is required. As a sensing means therefor, for example, magnetic sensors 7 such as Hall elements are attached at several places, and the rotation state of the motor is sensed to perform feedback control. FIG. 11 is a perspective view of a motor using a magnetic sensor. Reference numeral 7 denotes a magnetic sensor which is a sensing means, and shows a state in which the magnetic sensor 7 is arranged in a gap between the magnet 6 which is a field part and the motor base 8.
Magnetic sensor 7 using leakage magnetic flux from magnet 6
The fluctuation of the field is detected by. The drive current of the coil group 42 (42, 44) is controlled based on this detection result. The magnetic sensor 7 is placed in the gap between the magnet 6 and the lower part of the motor base 8.
Since it is arranged, it is not necessary to widen the magnetic gap or change the length of the magnetic gap. Therefore, the air gap between the field unit and the coil group 42 (42, 44) can be accurately maintained within a narrow range.

Next, the field magnet section will be described. The magnet 6 is formed of a ferromagnetic material in a cylindrical shape. The cylindrical peripheral surface portion facing the back yoke 3 is precision machined with high accuracy in outer diameter dimension and roundness. Therefore, the cylindrical peripheral surface portion is formed into a smooth and continuous peripheral surface. The cylindrical peripheral surface portion of the magnet 6 has a plurality of poles magnetized in the order of N, S, N, S ... in the circumferential direction, and the yoke 5 is fixedly held on the outer peripheral surface of the magnet 6. . This yoke 5 is a magnet 6
And functions as a yoke for increasing the gap magnetic flux density of the back yoke 3.

Further, the magnet 6 and the coil group 42 (4
The arrangement of the wound back yoke 3 of (2, 44) will be described. FIG. 12 is a diagram for explaining the attractive force between the magnet and the back yoke. An attractive force generated by the magnet 6 is generated between the magnet 6 and the back yoke 3. If the distance between the magnet 6 and the back yoke 3 is reduced, in order to overcome the attractive force between the magnet 6 and the back yoke 3, a larger torque for rotating the motor must be generated. On the contrary, if the distance between the magnet 6 and the back yoke 3 is increased in order to reduce the attractive force between the magnet 6 and the back yoke 3, the magnetic flux that crosses the coil 4 decreases, and the generated torque also decreases. Therefore, the distance between the magnet 6 and the back yoke 3 (gap length g)
Is an optimum positional relationship that minimizes the attractive force acting between the magnet 6 and the back yoke 3, maximizes the number of magnetic fluxes that traverse the coil 4, and maximizes torque generation.

In FIG. 10A again, g represents the gap length. When the back yoke 3 and the magnet 6 are made of the materials described at the beginning, 1.0 ≧ g ≧ 1.5 (m
In m), a motor having the required high torque and low cogging performance could be obtained.

Next, the rotating operation of the motor of the present invention will be described. 13A and 13B are views for explaining the magnetic circuit of the motor according to the embodiment of the present invention. FIG. 13A illustrates the magnetic flux of the back yoke, and FIG. 13B illustrates the magnetic flux of the magnet. Is. 13 (a), (b)
In (see FIGS. 5 and 9), the rotational force is generated by the DC motor according to Fleming's left-hand rule. The coil 4 (coil group 42) is arranged in the magnetic flux between the magnet 6 and the back yoke 3. This coil group 4
When a current flows through the second coil 4, an electromagnetic force according to Fleming's left-hand rule acts on the coil 4. That is, with respect to the magnetic flux passing from the magnet 6 toward the back yoke 3 (radial direction), the axial direction (same direction as the motor shaft) component of the current flowing through the copper wire of the coil 4 crosses the above magnetic flux, so that the coil 4 modulo The direction of the electromagnetic force is generated in the line direction, that is, the rotation direction.

When an electric current is passed through the coil 4, a magnetic flux flows in the back yoke 3. The magnetic flux generated in the back yoke 3 overlaps with the magnetic flux generated from the magnet 6 in the vector direction (see the arrow in FIG. 13). As a result, the magnetic flux traversing the coil 4 is further enhanced, and a larger torque can be generated. In particular, the convex portion 31 is formed on the back yoke 3 of the present invention, and the current switching portion of the coil 4 (see the connection point of the unit coil 41, the central portion, and the intermediate portion 33 described above) is arranged on the convex portion 31. Therefore, the convex portion 3
Since the magnetic flux is narrowed into a beam between the magnet 1 and the magnet 6, there is an effect that the magnetic flux is further strengthened.

Since the actual armature portion is on the fixed side, the field portion, that is, the magnet 6 and the yoke 5 rotate due to the reaction. Therefore, it becomes a rotating field type. Based on the positional relationship between the coil 4 and the magnet 6 using the signal of the magnetic sensor 7, the rotating force is generated in order by sequentially controlling the direction and the timing of the electric current applied to the coil 4.
The motor keeps rotating.

Next, the winding process of the coil 9 will be described. FIG. 14 is a diagram for explaining the winding process. 14
(A) is a figure explaining winding processing using the back yoke 3 of FIG. 14A, the ring-shaped back yoke 3 shown in FIG. 1 corresponds to the coil 4, the coil 4 inserted from the lower portion of the back yoke 3 is received (step 1), and the upper portion of the back yoke 3 receives the coil 4. A winding process of winding around 3 is performed (step 2).

Next, in order to facilitate the winding process of the coil 4, the entire circumference of the ring-shaped back yoke 3 is divided into a plurality of parts. For example, as shown in FIG. 14B, the entire circumference is divided into 9 in the circumferential direction (that is, divided into the number of coil groups 42), and the coil 4 is wound around the divided back yoke 3. A plurality of back yokes 3 around which the coil 4 is wound are joined by means such as welding to form the ring-shaped back yoke 3. That is, as shown in FIG. 14B, the coil 4 can be rotated and wound while feeding the back yoke 3. Alternatively, in FIG. 14C, the unit coil 41 may be preliminarily wound and formed, and the coil 4 may be attached to the divided back yoke 3. As described above, the winding process can be facilitated.

FIG. 15 is a diagram showing magnets arranged on the inner and outer circumferences. The difference from FIG. 1 and FIG. 6 is that the magnets 6 are arranged on both sides of the inner circumference and the outer circumference,
The coil 4 and the coil 4 are arranged so as to be sandwiched by the magnet 6. With the above configuration, electromagnetic force acts on the coil 4 from both the inner circumference and the outer circumference, so that a stronger torque can be generated.

Further, FIG. 16 is a diagram showing evaluation of temperature characteristics. In FIG. 16, the current consumption of the motor when the standard 12 cm disk is mounted on the motor and rotated is shown. The motor to be compared and contrasted is the motor described in FIG. 17 in the related art. Of course, the drive device for driving the motor has the same conditions. As shown in the figure, the motor having the structure of the present invention has almost constant current consumption (240 mA) in the range of 0 ° C. to 70 ° C. and shows no change. On the other hand, the conventional motor showed an increase of 14.2% from 360 (mA) to (411 mA).

Such an excellent temperature characteristic is such that the motor having the structure of the present invention has a gap length much smaller than that of the conventional motor and is substantially constant over the entire circumference of the rotor of the motor (the above-mentioned convex portion). This is because the permeance forming the magnetic circuit of the motor does not change due to temperature (in other words, the magnetic circuit of the motor does not include an element affected by temperature).

Since the motor having the structure of the present invention having such excellent temperature characteristics is used in the disk device, even if the battery capacity of the disk device (for example, laptop computer) is lowered at a low temperature, it is stable for a long time. The operation of is secured. Alternatively, a stable long-time operation is ensured even if the disk device is used for a long time and the internal temperature rises.

The above description has been made by taking the rotating field type outer rotor motor as an example. However, the present invention is not limited to the rotating field type outer rotor motor.
Whether the rotor is arranged on the inner circumference or the outer circumference is not the subject of the present invention and is merely a structural arrangement. Therefore, it is also possible to utilize the structure of the present invention to form an inner rotor structure. is there. Furthermore, it is likewise possible to arrange the field part on the fixed side and the armature part on the rotating side.

The motor of the present invention constructed as described above can generate a large torque. This is because the gap between the magnet and the back yoke can be narrowed due to the structure, and a high gap magnetic flux density can be secured. Similarly, structurally, since an electromagnetic force for rotating the motor is generated near the outermost circumference of the rotor (field portion), a large moment (radius) can be obtained, so that the motor torque can be increased. Furthermore, by forming a coil, it is possible to make a large number of coils. In addition, since the cylindrical magnet is arranged on the outer circumference and the number of poles to be magnetized can be increased, the torque constant can be improved and the motor torque can be increased. Therefore, if the loads are the same, it is possible to realize a motor with lower power consumption.

Further, in the motor having the structure of the present invention, since the coil is mechanically fixed to the back yoke, it can be made a rigid body, so that the vibration of the coil is almost eliminated. Further, since the magnetic flux generated in the back yoke directly acts on the coil, it is possible to increase the torque generated in the motor and at the same time to perform a quick acceleration / deceleration operation.
If the motor having such characteristics is used in the disk device, the access time and the power consumption can be reduced, and the disk device can be made thin.

It should be noted that the examples used in the description are not intended to limit the present invention to applications of spindle motors. For example, it is possible to extend the rotating field of the motor and the armature in the direction of the rotating shaft according to the configuration of the present invention, and by doing so, a motor with a small torque but a high torque and a small inertia and a low power consumption It is also possible to realize

As described in detail above, according to the present invention, there is provided a motor which has low power consumption, high efficiency, and small change in current consumption with respect to temperature change, and which can be made thin. Can be provided.

[0056]

As described in detail above, according to the present invention, a motor having a high efficiency with respect to power consumption and a small change in current consumption with respect to a temperature change, which can be made thin. Can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view of a motor according to an embodiment of the present invention.

FIG. 2 is a plan view of an essential part of FIG.

FIG. 3 is a diagram for explaining the coil winding method of FIG.

FIG. 4 is a diagram for explaining the coil connection of FIG.

FIG. 5 is a wiring diagram of all coils in FIG.

FIG. 6 is a perspective view of a motor having another winding.

FIG. 7 is a diagram for explaining the connection between adjacent coils in FIG.

FIG. 8 is a diagram illustrating the coil current of FIG.

FIG. 9 is a connection diagram of all coils in FIG.

FIG. 10 is a diagram illustrating details of a convex portion in FIG.

FIG. 11 is a perspective view of a motor using a magnetic sensor.

FIG. 12 is a diagram for explaining an attraction force between a magnet and a back yoke.

FIG. 13 is a diagram illustrating a magnetic circuit of a motor according to an embodiment of the present invention.

FIG. 14 is a diagram illustrating winding processing.

FIG. 15 is a diagram showing magnets arranged on the inner and outer circumferences.

FIG. 16 is a diagram showing evaluation of temperature characteristics.

FIG. 17 is a perspective view of a conventional circumferentially opposed motor.

FIG. 18 is a sectional view taken along line XX of FIG.

FIG. 19 is an explanatory diagram of the rotation operation of FIG.

FIG. 20 is a perspective view of a conventional face-to-face motor.

21 is a cross-sectional view taken along the line YY of FIG.

22 is an explanatory diagram of the rotation operation of FIG.

FIG. 23 is a magnetization distribution map of the magnet of FIG. 20.

[Explanation of symbols]

1 rotation axis 2, 21, 22 bearings 3 back yoke 4, 46, 47 coils 5,51 York 6, 61, 62 magnet 7 Magnetic sensor 8 motor base 9 coil hook 10 poles 13,34 turntable 15 chucking unit 16 chucking balls 31 convex 32 recess 41 unit coil 42, 43 coil group 49 coil board

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[Procedure amendment]

[Submission date] January 18, 2002 (2002.1.1
8)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

First, the yoke thickness t is set so as to secure a sufficient magnetic flux density, prevent eddy current loss, and reduce resistance loss of the coil 4. T to satisfy the former two
Is required to be increased, and t is required to be decreased to satisfy the latter. In the spindle motor of the disk device to which the present invention is applied, the yoke thickness t is 1.2 ≤
By setting t ≦ 2.0 (mm), a motor having a suitable low loss performance could be obtained.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0036

[Correction method] Change

[Correction content]

Next, the height h of the convex portion is determined by focusing the magnetic flux into a beam shape.
Depending on the effect of
Is set. Spin of disk device to which the present invention is applied
In the dollar motor, the height h of the protrusion is 0.1≦ h ≦
By setting it to 0.5 (mm), the required high torque
And a motor with low cogging performance can be obtained.
It was

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

Further, FIG. 10B is a view for explaining the angle of the convex portion. θ is the convex portion angle, and represents the angle that one convex portion 31 occupies in the front periphery of the back yoke 3. As described above, since the coil 4 is aligned and wound around the cylindrical portion of the back yoke 3 and the unit coil 41 is disposed so as to straddle the convex portion 31, the convex portion 31 is a region where no coil exists. Therefore, the region of the convex portion 31 becomes an important element for forming the magnetic flux in a beam shape. Especially, the turntable diameter is 29m
In the spindle motor for a disk device of m, when the three-phase armature coil is configured by three coil groups and the magnet 6 is configured by 12 poles (see FIG. 13 described later), θ =
It was possible to obtain a motor having the required high torque and low cogging performance at 5 ± 0.5 °. Further, if the number of poles of the magnet 6 is changed to 8 poles or 16 poles and the motor diameter is changed according to the number of poles by changing the coil group configuration to two or four, θ becomes 2 ° and 8 °. Is obtained.
That is, the optimum condition range of 2 ≤ θ ≤ 8 (degrees) can be obtained.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

In FIG. 10A again, g represents the gap length. When the back yoke 3 and the magnet 6 are made of the materials described at the beginning, 1.0 ≤ g ≤ 1.5 (m
In m), a motor having the required high torque and low cogging performance could be obtained.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeo Fukuda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Fumikawa Furukawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5H002 AA01 AB06 AE08                 5H603 AA01 AA09 BB05 BB12 BB13                       CA01 CA05 CB01 CC01 CC11                 5H621 AA02 BB07 GA14 JK03 JK04

Claims (17)

[Claims] 1. An armature having a cylindrical armature yoke and an armature coil wound around a cylindrical peripheral surface of the armature yoke, and a plurality of cylindrical armature coils formed on the cylindrical peripheral surface. A motor having a cylindrical field magnetized with magnetic poles, wherein the armature yoke includes a convex portion protruding from the armature yoke toward the cylindrical field magnet in a current switching portion of the armature coil. A motor characterized by being formed. 2. The motor according to claim 1, wherein a concave portion is formed on the back surface of the armature yoke corresponding to the convex portion. 3. An armature having a cylindrical armature yoke and an armature coil wound around a cylindrical peripheral surface of the armature yoke; and a plurality of cylindrical armature coils formed on the cylindrical peripheral surface. A motor having a cylindrical field magnetized with magnetic poles, wherein the armature yoke includes a convex portion protruding from the armature yoke toward the cylindrical field magnet in a current switching portion of the armature coil. A motor is characterized in that a concave portion is formed on the back surface of the armature yoke corresponding to the convex portion. 4. The motor according to claim 3, wherein the armature coil is closely wound on the cylindrical portion of the armature yoke where neither the convex portion nor the concave portion of the armature yoke exists. 5. An armature having a cylindrical armature yoke and an armature coil wound around a cylindrical peripheral surface of the armature yoke; and a plurality of cylindrical armature coils formed on the cylindrical peripheral surface. A motor having a cylindrical field magnetized with magnetic poles, wherein the armature yoke forms a protrusion protruding from the armature yoke toward the cylindrical field, and the armature yoke corresponds to the protrusion. A concave portion is formed on the back surface of the armature yoke, and the armature coil has two coils wound on both sides of the convex portion, and the winding end on one side and the winding end on the other side are connected to each other to form a group. A motor characterized by being an armature coil. 6. An armature having a cylindrical armature yoke and an armature coil wound around the cylindrical peripheral surface of the armature yoke, and a plurality of cylindrical armature coils formed on the cylindrical peripheral surface. A motor having a cylindrical field magnetized with magnetic poles, wherein the armature yoke has a convex portion protruding from the armature yoke toward the cylindrical field magnet, and the armature corresponding to the convex portion. A concave portion is formed on the back surface of the yoke, and a locking portion for locking the armature coil is formed on the convex portion, and the armature coil has a central portion formed in advance locked by the locking portion. A motor characterized by being wound on both sides of the convex portion. 7. The armature coil according to claim 5 or 6, wherein the armature coil is closely wound on the cylindrical portion of the back yoke where the convex portion and the concave portion of the armature yoke do not exist, and is wound in an aligned manner. motor. 8. The motor according to claim 1, wherein a gap between the armature yoke and the cylindrical field is arranged at a predetermined interval. 9. The motor according to claim 8, wherein the gap is set in the range of 1.0 to 1.5 (mm). 10. The angle of each of the protrusions is 2 to 8
The motor according to any one of claims 1 to 7, wherein the motor is set in a range of (degrees). 11. The height of the protrusion is 0.1 to 0.5 (m
The motor according to any one of claims 1 to 7, wherein the motor is set in a range of m). 12. The method according to claim 1, wherein the cylindrical field magnet is arranged on the outer circumference of the armature yoke, and the second cylindrical field magnet is arranged on the inner circumference of the armature yoke. 7. The motor according to any one of 7. 13. A disk drive, wherein the motor according to any one of claims 1 to 13 is used for rotationally driving a medium. 14. A winding method for winding an armature coil around a cylindrically formed armature yoke, wherein the armature yoke is a protrusion protruding from the armature yoke toward the cylindrical field. Part of the armature coil, and the armature coil has two coils wound on both sides of the convex portion in the same direction, and the winding end on one side and the winding end on the other side are connected to each other to form a group of armature coils. The winding method characterized in that 15. The armature yoke is preliminarily divided at a plurality of locations with the convex portion as a center, and armature coils formed in advance are mounted on the armature yoke from both sides of the convex portion,
15. The winding method according to claim 14, wherein the winding end on one side and the winding end on the other side are connected and the divided armature yokes are joined. 16. A winding method for winding an armature coil around a cylindrical armature yoke, wherein the armature yoke is a protrusion protruding from the armature yoke toward the cylindrical field. Part and a locking part for locking the armature coil are respectively formed, and a central part that is folded back to the armature coil is provided in advance, and the central part is locked to the locking part and the convex part is formed. A winding method characterized in that it is wound on both sides in the same direction. 17. The armature yoke is preliminarily divided at a plurality of locations centered on the convex portion, the armature coil is preliminarily provided with a folded central portion, and the central portion is locked to the locking portion. 17. The winding method according to claim 16, wherein the armature yokes are wound on both sides of the convex portion in the same direction and are joined together.