JPH07245926A - Brushless motor - Google Patents

Abstract

PURPOSE:To increase torque to be generated from a motor by inclining the facing part of at least one of rotor or stator against the axial direction of rotary shaft thereby increasing the area facing a rotor magnet. CONSTITUTION:The stator yoke 8a of a motor is substantially tapered by flattening the ridge on the rotor magnet side and laminating yokes having gradually increasing hole. The tapered rotor magnet 5a is magnetized vertically to the tapered surface in order to facilitate formation of a magnetic path having shortest distance in the gap between the rotor magnet 5a and the stator yoke 8a. When the number of slots is increased and the cross-sectional area of the stator yoke itself is decreased or the sectral surface facing the rotor can not be enlarged in the peripheral direction, the area facing the rotor magnet can be increased by tapering the rotor magnet and the magnetomotive force is used effectively. This structure increases torque to be generated from the motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC brushless motor as a rotary drive source used in, for example, a magnetic disk or optical disk drive.

[0002]

2. Description of the Related Art Conventionally, a technique relating to increasing the efficiency of a magnetic circuit by tapering a rotor magnet and a stator yoke has been disclosed in, for example, Japanese Utility Model Laid-Open No. 62-19063 and Japanese Patent Laid-Open No. 3-45151. There were things.

Conventional example 1. FIG. 28 shows the actual development number 62-190.
It is a principal part expanded sectional view of the conventional compressor electric motor shown by 63 publication. In the figure, 30 is a rotor, 80 is a stator, 90 is an air gap between the rotor 30 and the stator 80, and 100 is an electric motor unit. When the electric motor unit is not energized, the magnetic center of the stator and the center of the rotor are β
It is axially supported so that it can only be displaced. In the compressor electric motor configured as described above, the electric motor unit 10
0 acts so that the magnetic centers of the intermediate positions of the axial lengths of the stator 80 and the rotor 30 are on the same plane during operation, and the stator 80 and the rotor 30 have the same magnetic center on the rotating shaft 91. Axial thrust acts to correct the surface. Therefore, if the rotor 30 is preliminarily offset by β in the axial direction with respect to the stator 80 so as to generate an axial thrust corresponding to the total thrust load including the rotor 30 and the rotary shaft 91, the thrust load of the rotary shaft 91 may be increased. Is reduced. Further, by forming a tapered surface that widens in the same direction on the inner peripheral surface of the stator 80 and the outer peripheral surface of the rotor 30,
The air gap 90 is widened by shifting the rotor 30 in the axial downward direction by β with respect to the stator 80. Then, in order to start the electric motor, the electric motor unit 10 having a large starting torque is used.
Even if 0 is used, due to the electromagnetic attraction between the stator 80 and the rotor 30 at the time of starting, the stator 80 and the rotor 30
I try not to hit. In addition, since the air gap 90 has a wide gap at the time of starting, the starting torque of the electric motor unit 100 can be optimized without considering the hit by the electromagnetic attraction force between the stator 80 and the rotor 30. During operation, the rotor 30 moves so as to coincide with the magnetic center of the stator 80 and narrows the air gap 90. Therefore, magnetic leakage in this air gap is reduced, and the electric motor section 100 is operated with an optimum operating torque.
The motor efficiency can be improved.

Conventional example 2. Further, FIG. 29 shows Japanese Patent Laid-Open No. 3-45.
It is a side view of the permanent magnet synchronous generator shown by the 151st publication. In the figure, 30 is a rotor, 80 is a stator, and 9
0 is the air gap. The inner diameter of the stator and the outer diameter of the rotor are formed in a tapered shape so that the rotor can be moved in the axial direction to make the air gap variable and control the magnetic flux that generates the voltage.

Conventional example 3. Further, FIG. 30 is shown in JP-A-3-22.
This is an electromagnetic drive device for a diaphragm disclosed in Japanese Patent No. 8039.
In the figure, 30 is a rotor and 80 is a stator. By making the rotor and the stator face each other in the shape of a truncated cone, it is possible to reduce the outer diameter of the electromagnetic drive device and reduce the length in the direction of the rotation axis L while increasing the effective areas of the magnet and the coil. Here, the flat coil is arranged on the tapered surface, and only the flat rotor magnet is allowed.

Conventional example 4. A conventional example of a brushless motor is shown below. FIG. 31 shows, for example, the actual exploitation 63-14.
It is a partial cross-sectional perspective view which shows the structure of the conventional general brushless DC motor shown by 3070 gazette etc. In the figure, 1 is a rotating shaft, 2 is a bearing, 3 is a rotor yoke, 4 is a hub, 5 is a rotor magnet, 6 is a base, 7 is a housing, 8 is a stator yoke, 9 is a coil, 10 is a printed circuit board, and is the base 6. It is formed integrally. Eleven additional inertias may be attached. 12 is a stator holder.

In a conventional general brushless DC motor, a rotor is assembled by fitting a ring-shaped magnet 5 to a cup-shaped rotor yoke 3 and bonded to the rotary shaft 1 via a hub 4. The additional inertia 11 may be attached in some cases. The stator comprises a stator yoke 8 formed by stacking magnetic plates of the same shape, and a coil 9 wound around its slot portion. A stator holder 12 for floating and protecting the coil 9 and securing the positional accuracy of the stator.
Are attached below the stator yoke 8. Also,
Although not shown in the figure, a shield cover for preventing magnetic flux leaking from the stator, a protective cover for preventing damage to the coil 9, and the like are generally attached on the coil 9 of the stator in some cases.

Next, the operation will be described. In a general three-phase motor, the number of slots in the stator is a multiple of 3, and the coils for two slots are always energized to excite the stator yoke. At this time, magnetic interaction works with the rotor magnetic pole. The energization of the stator coil is given by the drive circuit so as to rotate in phase, so that the rotor magnet also receives torque due to the corresponding magnetic interaction and rotates. The torque generated at this time is, for example, the magnetic flux density on the outer peripheral surface of the rotor magnet,
It depends on the magnetic flux density generated on the inner peripheral surface of the slot of the stator yoke due to the coil energization and the surface area involved in the interaction at that time.

[0009]

In the motor and generator shown in the conventional example 1 and the conventional example 2, the stator and the rotor are formed in a tapered shape without paying attention to the thinning of the device. Is. Further, the electromagnetic drive device shown in Conventional Example 3 is intended to increase the effective area of the magnet and the coil while making the device thinner.
The flat coil, which was conventionally flat, is arranged in a tapered surface. Further, since the motor shown in Conventional Example 4 is configured as described above, when the motor is also made thin due to a request for thinning of the device in which the motor is mounted, the space around which the coil is wound is also increased. Since the size of the stator yoke is reduced, there arises a problem that the thickness of the stator yoke cannot be increased in the rotation axis direction. Further, the magnetic flux density of the rotor magnet and the stator yoke can be made by improving and developing the physical properties of the magnet and the yoke material, but there remains a problem of how to increase the surface area of interaction. In recent years, magnets have advanced remarkably and have been improved in performance, but even if a high-performance magnet is used for a rotor, a stator corresponding to it cannot be realized. Further, in order to obtain a motor with less fluctuation in rotation, it is necessary to reduce the fluctuation in driving torque by increasing the number of magnetizing poles in the magnet and the number of slots in the stator. There is a problem that the yoke cross-sectional area around the area decreases, and the magnetic flux of the rotor magnet cannot be sufficiently captured. Therefore, there is a problem that the drive torque cannot be obtained as the number of slots is increased to suppress the rotation fluctuation.

The present invention has been made to solve the above problems, and when a tapered rotor magnet and a tapered stator yoke adapted to the rotor magnet are arranged to increase the number of slots. By reducing the cross-sectional area of the stator yoke itself and the fact that the surface facing the rotor cannot be fanned out in the circumferential direction, the taper shape extends the distance in the direction of the rotation axis, and It is intended to increase the facing area of the motor, to effectively use the magnetomotive force, and to increase the torque generated by the motor.

[0011]

A brushless motor according to a first aspect of the present invention includes a rotating shaft supported by a base via a bearing, coupled to the rotating shaft, and a rotor magnet and a first rotating shaft.
And a stator on the base having a second facing portion at a position facing the first facing portion of the rotor, and at least one of the rotor and the stator is provided. The facing portion is formed to be inclined with respect to the axial direction of the rotating shaft.

In the brushless motor according to the second aspect of the present invention, both the first facing portion and the second facing portion are formed to be inclined with respect to the axial direction of the rotating shaft, and the respective inclination angles are equal. Characterize.

In a brushless motor according to a third aspect of the present invention, the rotor has a first yoke and a second yoke.
A rotor magnet is provided between the second yoke and the second yoke, and the end portion of the second yoke is inclined with respect to the axial direction of the rotating shaft to form the first facing portion.

A brushless motor according to a fourth aspect of the present invention is characterized in that the first yoke and the second yoke sandwich a rotor magnet in the axial direction of the rotary shaft.

A brushless motor according to a fifth aspect of the present invention is characterized in that the first yoke and the second yoke sandwich a rotor magnet in a direction orthogonal to the axial direction of the rotating shaft.

A brushless motor according to a sixth aspect of the invention is characterized in that the rotor magnet is magnetized in a direction inclined with respect to the axial direction of the rotating shaft.

A brushless motor according to a seventh aspect of the invention is characterized in that the rotor magnet is magnetized in a direction orthogonal to the axial direction of the rotating shaft.

A brushless motor according to an eighth aspect of the invention is characterized in that the rotor magnet is magnetized in the same direction as the axial direction of the rotary shaft.

A brushless motor according to a ninth aspect of the invention is characterized in that the rotor magnet is magnetized with polar anisotropy.

A brushless motor according to the tenth invention is
The stator is characterized by including a stator yoke in which a plurality of magnetic plates are stacked to form a second facing portion whose end is inclined with respect to the axial direction of the rotating shaft.

A brushless motor according to an eleventh invention is
The stator is characterized in that a plurality of magnetic plates having different sizes are overlapped with respect to the axial direction of the rotating shaft to incline the second facing portion with respect to the axial direction of the rotating shaft.

A brushless motor according to the twelfth invention is
The stator is characterized in that a plurality of magnetic plates are overlapped with each other, and an end portion of the stator is secondarily processed to incline the second facing portion.

A brushless motor according to a thirteenth invention is
One or both of the first and second facing portions are provided with a step portion and face each other.

A brushless motor according to a fourteenth invention is
The stator is provided in an arc shape on the outer peripheral portion of the rotor.

[0025]

In the brushless motor according to the first aspect of the present invention, the facing area can be increased by forming at least one of the facing portion of the rotor and the stator inclining with respect to the axial direction of the rotating shaft. , Magnetomotive force can be used effectively.

In the second invention, both the first facing portion of the rotor and the second facing portion of the stator are formed so as to be inclined with respect to the axial direction of the rotating shaft, and the respective inclination angles are equal. The first facing portion and the second facing portion are parallel or substantially parallel.

In the brushless motor according to the third invention, the rotor has a second yoke different from the first yoke, and a rotor magnet is provided between the first yoke and the second yoke. Since the end portion of the second yoke is inclined with respect to the axial direction of the rotating shaft to form the first facing portion, it is not necessary to perform special processing on the rotor magnet, and processing and magnetization can be easily performed. .

In the brushless motor according to the fourth aspect of the present invention, the first yoke and the second yoke hold the rotor magnet in the axial direction of the rotating shaft, so that the shape of the magnet can be easily obtained from the market. It may be a ring-shaped disc having a rectangular cross section. Furthermore, since the second yoke can be used as a magnetic path, the magnetizing direction of the magnet can be the axial direction that is most easily magnetized.

In the brushless motor according to the fifth aspect of the present invention, the first yoke and the second yoke hold the rotor magnet in a direction orthogonal to the axial direction of the rotating shaft. A ring-shaped disc with a rectangular cross section that can be easily obtained from the market can be used. In addition, the manufacture and magnetization of the rotor magnet are facilitated.

In the brushless motor according to the sixth aspect of the invention, the rotor magnet is magnetized in a direction inclined with respect to the axial direction of the rotating shaft, and is perpendicular to the surfaces of the first facing portion and the second facing portion. By being magnetized in the direction, a magnetic path can be formed between the first facing portion and the second facing portion at a shorter distance.

In the brushless motor according to the seventh aspect of the present invention, the rotor magnet is magnetized in a direction orthogonal to the axial direction of the rotating shaft, and exhibits an effective magnetomotive force in accordance with the inclination angle of the facing portion. can do. Magnetization is also relatively easy.

In the brushless motor according to the eighth aspect of the present invention, the rotor magnet is magnetized in the same direction as the axial direction of the rotary shaft, and can exert an effective magnetomotive force depending on the inclination angle of the facing portion. it can. In addition, it is the easiest magnetization direction and is easy to process.

In the brushless motor according to the ninth aspect of the present invention, since the rotor magnet is magnetized with polar anisotropy, a magnetic path can be formed inside the magnet.

In the brushless motor according to the tenth aspect of the invention, since the stator yoke has a plurality of magnetic plates which are superposed on each other to form a second facing portion which is inclined with respect to the axial direction of the rotating shaft, the stator yoke is processed. Will be easier.

In the brushless motor according to the eleventh aspect of the invention, the stator has a second facing portion in the axial direction of the rotary shaft by stacking a plurality of magnetic plates having different sizes in the axial direction of the rotary shaft. It is inclined. The magnetic plate used here may be punched only, and secondary machining such as chamfering is unnecessary.

In the brushless motor according to the twelfth aspect of the invention, the stator has the second facing portion inclined by stacking a plurality of magnetic plates and secondarily processing the ends thereof.

A brushless motor according to a thirteenth invention is
One or both of the first and second facing portions are provided with a step portion and face each other, which facilitates manufacturing. Further, when both are provided with stairs, the distance between the respective parts can be kept constant.

In the brushless motor according to the fourteenth invention, the stator is provided in an arc shape on the outer peripheral portion of the rotor. This makes it possible to utilize the open space,
For example, if a write / read head of a recording medium is arranged, a compact structure of the recording device can be taken.

[0039]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional perspective view showing the structure of a DC brushless motor according to the present invention. FIG. 2 is a sectional view (axial sectional view) including a rotating shaft, showing Embodiment 1 of the present invention. In the figure, 1 is a rotary shaft, 2 is a bearing, 3a is a tapered rotor yoke, 4 is a hub, 5a is a tapered rotor magnet, 6 is a base, 7 is a housing, 8a is a substantially tapered stator yoke, and 9 is a Coil, 10 is a printed circuit board, 11 is additional inertia, 12 is a stator holder, and 15 is a rotor disk. D according to this embodiment
In the C brushless motor, as shown in FIG. 2, the stator yoke 8a chamfers the ridge line on the rotor magnet side,
By gradually overlapping the yokes with larger hole diameters, a roughly tapered shape is realized. Further, in the example of the drawing, as shown by the arrow, the tapered rotor magnet 5a is magnetized substantially perpendicular to the tapered surface forming the outer circumference. It is the rotor magnet 5a that the magnetization direction is perpendicular to the tapered surface.
This is for facilitating the formation of a magnetic path in the gap between the stator yoke 8a and the shortest distance. As shown in FIG. 3, the distance that the magnetic flux passes is the shortest when the magnetization direction is perpendicular to the tapered surface. That is, Z <X and Z <Y. Furthermore, when the number of slots is increased, the amount of reduction in the cross-sectional area of the stator yoke itself and the amount of inability to expand the surface facing the rotor in a fan shape in the circumferential direction are tapered so that By increasing the facing area and effectively using the magnetomotive force, the torque generated by the motor can be increased.

As described above, in this embodiment, the rotary shaft supported by the base via the bearing, the rotor coupled to the rotary shaft, the rotor magnet constituting the rotor, and the rotor yoke, A stator composed of an iron core yoke or the like with a coil wound is arranged at a position on the base facing the rotor magnet, and both the rotor magnet and the stator are formed in a substantially tapered shape. I am trying. Further, when the magnetization direction of the magnet is viewed in an axial cross section, it is magnetized in an oblique direction that is neither orthogonal nor parallel to the rotor rotation axis, including a direction orthogonal to the tapered surface of the rotor magnet. To do.

Further, the stator is characterized in that magnetic plates are superposed on each other, and a substantially tapered surface is formed in accordance with a tapered surface of the rotor magnet by subjecting a tip end to bending processing or corner chamfering processing. .

The difference between this embodiment and the conventional one is that the motor in this embodiment is a motor used in a flexible disk device, so that it is necessary to make it particularly thin. In order to improve the reduction of the torque of the motor caused by the reduction of the speed, the opposed portions of the stator and the rotor are tapered. Both the rotor and the stator are made as thin as possible in the axial direction. A major feature of this thinning is that the area where the rotor and the stator face each other is reduced by the taper portion. Conventional example 1
The electric motor and the generator shown in Conventional Example 2 are not provided with the taper portion in order to improve the drawbacks due to the reduction in thickness, but with the taper portion for a completely different purpose. Further, since the electromagnetic drive device shown in the conventional example 3 is composed of the flat coil and the flat magnet, the structure is different from the case where the facing portions of the stator and the rotor are inclined as in this embodiment. Is. That is, in this embodiment, the facing surface of the stator and the rotor is formed so that the motor shown in Conventional Example 4 is parallel to the axial direction of the rotating shaft, whereas the motor is made thinner. A characteristic point is that the facing surfaces of the stator and the rotor are formed in a direction inclined with respect to the axial direction of the rotating shaft as illustrated.

Example 2. FIG. 4 is a partial axial sectional view showing another embodiment of the present invention. In the first embodiment, the ridgeline on the rotor side of the stator yoke is chamfered to realize the tapered shape. However, the stator yoke 8b is formed by the sintering method or
It may be integrally formed into a taper shape by a die casting method or the like. In addition, the rotor yoke 3b is formed into a cup shape and is directly coupled to the hub 4. At this time, the structure can be simplified as compared with the first embodiment. Also, the magnet 5
When viewed in a section of the rotor rotation axis, b has a substantially triangular shape, and the magnetization direction is magnetized substantially perpendicular to the hypotenuse of the triangle parallel to the hypotenuse of the stator yoke 8b, as in the first embodiment. Further, the magnetization direction of the magnet can be made anisotropic. In this way, the magnetization can be strengthened by making the magnetization direction of the magnet anisotropic.

Example 3. FIG. 5 is a partial axial sectional view showing another embodiment of the present invention. In Examples 1 and 2,
The magnetizing direction of the magnet was made almost perpendicular to the taper surface,
In this embodiment, the magnetizing direction of the rotor magnet 5c is the radial direction as in the conventional example. At this time, although the torque of the motor tends to decrease, the magnetizing device of the magnet may be substantially the same as the conventional one, and the magnetizing becomes easier as compared with the above embodiment. Further, the magnetizing direction of the magnet may have radial anisotropy. Although any of the above-described embodiments can be applied to the stator yoke, an example of the stator yoke 8a according to the first embodiment is shown here.
The rotor yoke 3c is a separate component, but a cup-shaped rotor yoke 3b as shown in FIG. 4 may be used. Further, the embodiment is an example in which the additional inertia 11 is separately attached, and functions to suppress the rotation fluctuation.

As described above, this embodiment is characterized in that the magnetization direction of the rotor magnet is magnetized in the radial direction with respect to the rotation axis of the rotor.

Example 4. FIG. 6 is a partial axial sectional view showing another embodiment of the present invention. In Examples 1 and 2,
Although the stator yoke has been chamfered or integrally molded, in the stator yoke 8c of the present embodiment, the magnetic material is made thinner so that the hole diameter increases from the smaller hole diameter to the larger one. In this example, the surfaces are overlapped with each other to form a substantially tapered surface. The stator yoke according to the present embodiment does not require secondary machining such as chamfering, and only punching is required, which facilitates machining. The rotor magnet 5c is the same as that of the third embodiment, but the rotor yoke has a laminated structure, that is, the ring-shaped rotor yoke also serves as an additional inertia and has a two-part configuration of 3d and 3e. A laminated structure of three or more parts is naturally possible. This has the effect of improving the magnetic characteristics and suppressing rotational fluctuations. However, the rotors of the first, second, and third embodiments can also be applied.

As described above, in this embodiment, the yoke of the stator is characterized in that a large number of thin magnetic plates are superposed and a substantially tapered surface is formed corresponding to the tapered surface of the rotor magnet. And

Further, the yoke of the stator is characterized in that magnetic plates are superposed on each other, and each plate is formed so as to be in a stepwise shape by being combined with the tapered surface of the rotor magnet, and arranged with an appropriate gap. And

Example 5. FIG. 7 is a plan view showing another embodiment of the present invention, and FIG. 8 is an axial sectional view thereof. Further, FIG. 9 is a side surface of the rotor magnet viewed from the same direction as FIG. 8, and N poles and S poles are alternately arranged on the outer peripheral surface.
In the first to fourth embodiments, the magnetizing direction of the rotor magnet is substantially perpendicular to the taper surface, or simply in the radial direction, but in the embodiment of this figure, the magnetizing direction of the rotor magnet 5d is as shown in FIG. As shown, the outer peripheral surface is almost the same as the conventional example, but when viewed in a cross section perpendicular to the rotation axis, it exhibits polar anisotropy. That is, as shown in FIG.
The magnetic lines of force passing from the magnetic pole N on the outer peripheral surface of d and passing through the inside of the magnet are magnetized so as to be curved and return to the outer peripheral surface without passing through to the inner peripheral surface to form an adjacent S pole. That is, since a magnetic path is formed inside the magnet, a path outside the magnet is unnecessary. According to this, the gap between the rotor magnet and the stator is less likely to be affected by the rotor yoke, and therefore, the rotor yoke can be omitted. Although any of the above-described embodiments can be applied to the stator yoke, an example in which the stator yoke of the first embodiment is used is shown here.

As described above, in this embodiment, the magnetization direction of the rotor magnet is the same as that of the surface of the rotor magnet on the stator side, and the magnetized shape is polar anisotropy. And

Example 6. FIG. 10 is a partial axial sectional view showing another embodiment of the present invention. In Examples 1 and 2,
Although the rotor magnet is magnetized substantially perpendicularly to the tapered surface, the rotor magnet 5e of this embodiment is magnetized in the direction of the rotating shaft 1. The rotor yoke 3f in this embodiment is directly connected to the hub 4 and has a disc shape. Magnetization of the rotor magnet in the present embodiment is easier than the radial magnetization in the third and fourth embodiments.
In addition, the manufacturing of the rotor magnet becomes easy. Further, the magnet can be strengthened by providing anisotropy in the direction of the rotation axis. In addition, an example in which a non-magnetic additional inertia 11 is attached to the position where the rotor yoke is attached is shown. This has the effect of suppressing rotational fluctuations.

As described above, this embodiment is characterized in that the magnetizing direction of the rotor magnet is magnetized in the rotational axis direction of the rotor.

Example 7. FIG. 11 is a partial axial sectional view showing another embodiment of the present invention. In the above-described embodiment, the outer peripheral portion of the rotor magnet is formed in a tapered shape, but as shown in the figure, the rotor magnet 5f having a stepped outer peripheral portion and the magnetic plate having a gradually different inner diameter are superposed on each other. This is an example in which the stator yokes 8d having a shape are arranged with an appropriate gap. The magnetizing direction of the magnet can be the diagonal direction of the first and second embodiments, the radial direction of the third embodiment, and the rotation axis direction of the sixth embodiment. Further, an example is shown in which the rotor yoke 3c is connected as a separate component to the non-magnetic rotor disk 15 which is also greatly extended to serve as additional inertia. As a result, fluctuations in rotation can be suppressed. The stator yoke of the present embodiment does not require secondary processing such as chamfering as in the case of the above-described fourth embodiment, and only punching is required, which facilitates processing. Furthermore, the number of components can be reduced. Here, the concept of determining the magnetization direction will be described with reference to FIG.
As shown in FIG. 12, it is efficient to set the direction in which the length of the magnetic path becomes smaller as the magnetization direction depending on the angle formed by the tapered surfaces of the rotor magnet and the stator with respect to the axial direction of the rotating shaft. For example, in the case of selecting one of two types of magnetization directions, that is, the axial direction of the rotation axis and the direction perpendicular to the rotation axis, in the case of FIG. 12A, both magnetization directions are the same, but FIG. In the case of (1), it is easier to form a magnetic path between the gaps and to form a short distance by magnetizing in the vertical axis direction than in the rotation axis direction. FIG. 12C shows the opposite case.

Example 8. 13 is a partially cutaway plan view showing another embodiment of the present invention, and FIG. 14 is an axial sectional view thereof. In the figure, 13 is a shield cover, and 14 is a protective cover, which is an example of a stator of 21 slots out of 24 slots, which lacks 3 slots. The rotor structure is the same as that of the fourth embodiment, and the stator yoke structure is the same as that of the first embodiment. If the motor is a three-phase drive, a structure lacking three slots is also possible. If, for example, a write / read head of a recording medium is arranged in a space lacking three slots, a compact structure of the recording device can be adopted. For example, when arranging the magnetic head, the shield cover 13 is necessary as a magnetic shield for the magnetic flux leaked from the rotor and the stator. Further, the coil 9 is generally provided with a protective cover 14 in order to protect it from a physical external force and to prevent it from being damaged.

As described above, in this embodiment, in the stator of the inner rotor type motor composed of the rotor, the rotor magnet, the rotor yoke, and the stator, the stator yoke of three slots is eliminated as the three-phase drive, for example. It is characterized in that an arc-shaped stator is formed and a physical space is generated in the radial direction of the outer circumference of the rotor.

Example 9. FIG. 15 is a partial axial sectional view showing another embodiment of the present invention. In the above-described embodiment, the tapered surface is formed by the rotor magnet, but another rotor yoke 31 is attached to the opposite surface of the rotor yoke 3f with the rotor magnet 5g interposed therebetween, and the outer periphery of the other rotor yoke, for example, is extended to form a tapered shape. You may form. In this case, the rotor magnet 5g may be a ring-shaped disc having a rectangular cross section, and can have the same rotor magnet shape as that of the flat air core coil motor, so that the magnet can be easily processed and magnetized. In addition, since anisotropy can be imparted to the rotation axis direction, strong magnetization can be achieved. When magnetizing in the radial direction, a special magnetizing yoke is required, and since the magnetizing directions are not parallel, strong magnetizing is difficult. When magnetizing in the direction of the rotation axis, it suffices to pinch the ring-shaped disc from above and below, and the magnetizing directions are also parallel.
Strong magnetization is possible. Further, since the non-magnetic additional inertia 11a can be arranged in the empty space around the outer periphery of the separate rotor yoke 31, it has an effect of suppressing the rotation fluctuation. Further, although the stator yoke 8a has the same configuration as that of the first embodiment and the like, it is integrally formed as in the second embodiment, or a large number of yokes as in the fourth embodiment are stacked to form a substantially tapered surface. A configuration is also possible. Further, the shape of the separate rotor yoke 31 is narrowed at the outer peripheral end to converge the magnetic flux of the rotor magnet 5g, and the divided surface of the N pole and the S pole is smoothly connected to smooth the change of the magnetic flux. It is also possible to adjust.

As described above, in this embodiment, the rotating shaft supported by the base through the bearing, the rotor coupled to the rotating shaft, the rotor magnet constituting the rotor, and the rotor yoke, A stator including an iron core yoke wound with a coil is arranged at a position on the base facing the rotor magnet, and the magnetizing direction of the rotor magnet is magnetized in the rotation axis direction of the rotor. An extended rotor yoke different from the rotor or rotor yoke to which the two are joined, and the rotor magnet is sandwiched between the extended rotor yoke and the extended rotor yoke. For example, the extended rotor yoke extends in the outer peripheral direction of the rotor, and the extended portion is formed in a substantially tapered shape. It is characterized by

Example 10. FIG. 16 is a partial axial sectional view showing another embodiment of the present invention. In the ninth embodiment, the separate rotor yoke 31 is attached and the outer periphery of the rotor yoke is extended to form a taper shape. However, the outer periphery of the different rotor yoke 31b is formed to form a step, and the separate rotor yoke 31a is formed. The stator yoke 8d, which is formed in a stepped shape by stacking magnetic plates having gradually different inner diameters, may be arranged with an appropriate gap. At this time,
The non-magnetic additional inertia 11b can be arranged in a vacant space around the outer periphery of the separate rotor yoke 31a. The rotor magnet 5g of this embodiment, another rotor yoke 31a,
Regarding the effect regarding the additional inertia 11b, it can be said that it is the same as that of the ninth embodiment. Further, as in the case of the eighth embodiment, the three-phase motor can be configured by removing the three slots of the stator yoke. If, for example, a write / read head of a recording medium is arranged in a space lacking three slots, a compact structure of the recording device can be adopted.

As described above, in this embodiment, the rotor, the rotor yoke, the rotor magnet, the extension rotor yoke, and the stator are formed, and the extension rotor yoke extends, for example, in the outer peripheral portion, and is provided on the axial base side of the rotor. In the meantime, the radius is gradually expanded or reduced to form a step shape, and the stator is characterized in that magnetic plates are overlapped with each other and each plate is formed so as to interlock with each step of the rotor. Further, in the stator, for example, as a three-phase drive, an arc-shaped stator in which a stator yoke of three slots is removed is formed to secure a physical space in a radial direction of the outer circumference of the rotor.

Example 11. FIG. 17 is a plan view showing another embodiment of the present invention. FIG. 18 is an axial sectional view of the embodiment. In the above embodiment, the taper surface is formed by the rotor magnet, but the additional ring yoke 32 is attached to the rotor yoke 3g so as to face the rotor magnet 5h and the outer ring surface of the additional ring yoke 32 is tapered. It may be configured to be formed in. In this case, the rotor magnet 5h may be a ring-shaped disc having a rectangular cross section. Therefore, the rotor magnet can be easily manufactured and magnetized. Further, the additional ring yoke 32 can have a function as an additional inertia. Furthermore, in Example 9 above.
The magnetic flux of the magnet can be adjusted in the same manner as in. Also,
As shown in FIG. 19, similarly to the fourth embodiment, the stator yoke may be formed by thinning the magnetic material and stacking it in order from the smaller hole diameter to the larger hole diameter to form a substantially tapered surface. Further, the magnetic poles of the rotor magnet can be made to have radial anisotropy or polar anisotropy.

As described above, in this embodiment, in the medium drive motor for a storage device such as a magnetic disk, the rotating shaft supported by the base through the bearing, the rotor coupled to the rotating shaft, and the rotor are provided. A rotor magnet, a rotor yoke, and an additional ring yoke that are configured, and on the base,
A stator composed of an iron core yoke wound with a coil is arranged at a position facing the additional ring yoke of the rotor magnet, and the rotor magnet has a cylindrical shape and is sandwiched between the rotor yoke and the additional ring yoke. The additional ring yoke and the stator are both formed in a substantially tapered shape or a substantially tapered hole shape.

As described above, in this embodiment, the yoke of the stator is formed by stacking a plurality of thin magnetic plates and forming a substantially tapered surface corresponding to the tapered surface of the additional ring yoke. Characterize.

Example 12 FIG. 20 is a partial axial sectional view showing another embodiment of the present invention. In Example 11 above,
The additional ring yoke 32 is attached and the outer peripheral surface of the additional ring yoke 32 is formed in a tapered shape. However, instead of the tapered shape, the additional ring yoke 32a is formed in a stepped outer peripheral surface and the inner diameter is gradually increased. The stator yoke 8d, which is formed by stacking the above magnetic plates in a stepped shape, may be arranged with an appropriate gap. According to this, similarly to the fourth embodiment, the stator yoke of the present embodiment does not require secondary processing such as chamfering, and requires only punching, which facilitates processing. Furthermore, the number of components can be reduced. At this time, since the additional ring yoke 32a functions as an additional inertia as in the above-described embodiment, it has an effect of suppressing the rotation fluctuation. Further, the magnetic flux of the magnet can be adjusted as in the case of the ninth embodiment. Further, as in the case of the eighth embodiment, a three-phase motor can be configured by removing the three slots of the stator yoke, and the write / read head of the recording medium can be provided in the space lacking the three slots. By arranging, a compact structure can be adopted as the recording device.

Further, the additional ring yoke is formed in a stepwise manner by gradually reducing or expanding the radius toward the base in the rotor rotation axis direction, and the stator is formed by stacking magnetic plates on top of each other. , Each plate is formed so as to interlock with each step of the additional ring yoke.

Further, in the stator of the inner rotor type motor, for example, as a three-phase drive, an arc-shaped stator in which the stator yoke of three slots is removed is formed, and a physical space is generated in the radial direction of the outer circumference of the rotor. It is characterized by

Example 13. 21 to 25 are views showing another embodiment of the present invention. In the first to twelfth embodiments, the rotor magnet 5 and the separate rotor yoke 31,
The taper shape of the additional ring yoke 32 is formed so as to have a small diameter on the base 6 side. As a result, when no electricity is applied to the tapered stator yoke, the magnetic flux is generated by the base 6
Direction or the diagonal direction to the base 6, an attractive force acts on the magnetic substance, and the rotor can be attracted to the base side, so the hub of the rotor is pressed in the thrust direction of the bearing and the preload to the bearing is applied. As a result, it is possible to simplify the bearing structure by omitting the preload spring. In this embodiment, the base 6 has a large diameter. FIG. 21 is a partial cross-sectional perspective view of an embodiment in which the large diameter and the small diameter of the first embodiment are exchanged. FIG. 22 is also a partial axial cross-sectional view. In addition, FIG. 23 shows the third embodiment.
FIG. 3 is an axial cross-sectional view showing an example in which the arrangement of the small diameter and the large diameter of the taper shape is reversed. FIG. 24 is an axial sectional view showing an example in which the arrangement of the small diameter and the large diameter of the tapered shape of the seventh embodiment is reversed. Further, FIG. 25 is an axial sectional view showing an embodiment in which the arrangement of the small diameter and the large diameter of the taper shape of Embodiment 6 is reversed. In this embodiment, almost the same effect as in the above-described first to twelfth embodiments can be obtained, but in this case, since the large diameter of the taper shape of the rotor is larger than the inner diameter of the stator, it is not necessary to install a special rotor retainer. The rotor will not come off due to impact. When such a structure is adopted, there is an advantage that the rotor part does not come off, but during the rotation of the motor, the force that lifts the rotor works, so press it in some way and make no contact. It is desirable to hold it.

Example 14 Also, as shown in FIG.
Similar taper-shaped rotor magnets and the like can be applied to the radial gap motor of the outer rotor.

Example 15 In the embodiment described above,
Although the example in which both the first facing portion and the second facing portion are inclined is shown, one of them may be inclined as shown in FIG. 27. When one of them is inclined, the gap is not constant and the motor torque tends to decrease. However, as shown in FIG. 12 (c), the tapered surface should be as parallel to the axial direction of the rotating shaft as possible. Therefore, it is desirable that the motor torque does not decrease. As described above, when one of the first facing portion and the second facing portion is inclined, there is an advantage that the other one having the conventional configuration can be used as it is.

[0069]

According to the first aspect of the present invention, at least either the rotor magnet or the stator yoke facing the rotor magnet is formed in a tapered shape to increase the thickness of the stator yoke in the rotation axis direction. Without
The area of the facing portion can be increased, and the magnetomotive force can be effectively used. Further, the rotor and the stator can be thinned. Further, since the magnetic flux of the high-performance magnet can be sufficiently guided to the stator yoke, it is possible to configure a thin motor having a large generated torque. In addition, compared to a motor of the same thickness, while securing a sufficient surface area,
The number of slots in the stator can be increased. At the same time, a space for mounting the additional inertia can be secured, which has an effect of reducing fluctuations in the rotation of the motor.

According to the second aspect of the invention, both the first facing portion of the rotor and the second facing portion of the stator are formed to be inclined with respect to the axial direction of the rotating shaft, and the inclination angles are the same. , The first facing portion and the second facing portion are parallel,
The magnetic flux density of the first facing portion and the magnetic flux density of the second facing portion can act more effectively.

According to the third invention, since the end portion of the second yoke is inclined with respect to the axial direction of the rotating shaft to form the first facing portion, the rotor magnet can be formed flat. Therefore, it is not necessary to perform special processing on the rotor magnet, and there is an effect that the magnet can be easily processed and magnetized at a low cost. In addition, since a space for installing the additional inertia can be secured, it is effective in reducing the rotation fluctuation of the motor.

According to the fourth invention, the first yoke and the second yoke
Since the yoke holds the rotor magnet in the axial direction of the rotating shaft, the shape of the magnet can be a ring-shaped disc having a rectangular cross section. Further, since the second yoke can be used as a magnetic path, the magnetizing direction can be set to the axial direction that is the easiest to magnetize, and like the third invention, the magnet can be easily machined and magnetized and is inexpensive. There is an effect that can be.

According to the fifth invention, the first yoke and the second yoke
Since the yoke holds the rotor magnet in the direction orthogonal to the axial direction of the rotating shaft, the shape of the magnet can be a ring-shaped disc having a rectangular cross section. or,
The rotor magnet can be easily manufactured and magnetized.

According to the sixth aspect of the invention, the rotor magnet is magnetized in a direction inclined with respect to the axial direction of the rotating shaft, so that the space between the first facing portion and the second facing portion is further increased. A magnetic path can be formed in a short distance, and torque can be obtained by more effective magnetic interaction.

According to the seventh aspect of the invention, the rotor magnet is magnetized in the direction orthogonal to the axial direction of the rotating shaft, so that the magnet can be magnetized easily and at a low cost.

According to the eighth aspect of the invention, the rotor magnet is magnetized in the same direction as the axial direction of the rotating shaft, so that the magnet can be magnetized most easily and at a low cost.

According to the ninth aspect of the invention, if a polar anisotropic magnet is used, a magnetic path can be formed inside the magnet, and the influence of the rotor yoke (or back yoke) at the gap between the rotor magnet and the stator can be prevented. It becomes difficult to receive. Therefore, it is possible to omit the rotor yoke,
This has the effect of making the motor cheaper.

According to the tenth aspect of the invention, the stator yoke has a plurality of magnetic plates which are superposed on each other to form a second facing portion which is inclined with respect to the axial direction of the rotating shaft, and thus is easy to process. Becomes

According to the eleventh aspect of the invention, in the stator, the second facing portion is inclined with respect to the axial direction of the rotating shaft by stacking a plurality of magnetic plates having different sizes in the axial direction of the rotating shaft. ing. The magnetic plate used here may be punched only, and secondary machining such as chamfering is unnecessary.

According to the twelfth aspect of the invention, the stator is manufactured by stacking a plurality of magnetic plates as in the conventional case, and the end portions thereof are two.
Since the second facing portion is inclined by the subsequent processing, the conventional stator manufacturing process can be used as it is.

According to the thirteenth invention, one of the first and second facing portions is provided with a step portion and faces each other, which facilitates manufacturing. Also, the other party also has a staircase,
This prevents the formation of uneven gaps when one is a staircase.

According to the fourteenth invention, the stator is provided in an arc shape on the outer peripheral portion of the rotor. This makes it possible to utilize the free space, and for example, by disposing the write / read head of the recording medium, a compact structure can be taken as the recording device.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view and perspective view showing a mechanism according to a first embodiment of the present invention.

FIG. 2 is a partial axial cross-sectional view showing the mechanism according to the first embodiment of the present invention.

FIG. 3 is a partially enlarged view showing the mechanism according to the first embodiment of the present invention.

FIG. 4 is a partial axial sectional view showing a mechanism according to a second embodiment of the present invention.

FIG. 5 is a partial axial cross-sectional view showing a mechanism in Embodiment 3 of the present invention.

FIG. 6 is a partial axial sectional view showing a mechanism according to a fourth embodiment of the present invention.

FIG. 7 is a partial cross-sectional plan view showing a mechanism in Embodiment 5 of the present invention.

FIG. 8 is an axial sectional view showing a mechanism in Embodiment 5 of the present invention.

FIG. 9 is a diagram showing a magnetization direction on an outer peripheral surface of a rotor magnet according to a fifth embodiment of the present invention.

FIG. 10 is a partial axial sectional view showing a mechanism in Embodiment 6 of the present invention.

FIG. 11 is a partial axial cross-sectional view showing a mechanism in Embodiment 7 of the present invention.

FIG. 12 is a diagram showing an angle formed by a tapered surface of the present invention and a magnetization direction.

FIG. 13 is a partial cross-sectional plan view showing a mechanism in Embodiment 8 of the present invention.

FIG. 14 is an axial sectional view showing a mechanism in Embodiment 8 of the present invention.

FIG. 15 is a partial axial cross-sectional view showing a mechanism in Embodiment 9 of the present invention.

FIG. 16 is a partial axial cross-sectional view showing a mechanism in Embodiment 10 of the present invention.

FIG. 17 is a partial cross-sectional plan view showing a mechanism in Embodiment 11 of the present invention.

FIG. 18 is an axial sectional view showing a mechanism in Embodiment 11 of the present invention.

FIG. 19 is an axial sectional view showing a mechanism in Embodiment 11 of the present invention.

FIG. 20 is a partial axial cross-sectional view showing the mechanism of Embodiment 12 of the present invention.

FIG. 21 is a partial cross-sectional view and perspective view showing a mechanism in Embodiment 13 of the present invention.

FIG. 22 is a partial axial cross-sectional view showing the mechanism of Embodiment 13 of the present invention.

FIG. 23 is a partial axial cross-sectional view showing the mechanism of Embodiment 13 of the present invention.

FIG. 24 is a partial axial cross-sectional view showing a mechanism in Embodiment 13 of the present invention.

FIG. 25 is a partial axial cross-sectional view showing the mechanism of Embodiment 13 of the present invention.

FIG. 26 is a partial cross-sectional view and perspective view of a radial gap motor of an outer rotor according to a fourteenth embodiment of the present invention.

FIG. 27 is a partial axial cross-sectional view showing the mechanism of Embodiment 15 of the present invention.

FIG. 28 is a diagram showing an example in which a conventional rotor and stator are tapered.

FIG. 29 is a diagram showing an example in which a conventional rotor and stator are tapered.

FIG. 30 is a diagram showing an example in which a conventional rotor and stator are tapered.

FIG. 31 is a partial cross-sectional perspective view showing the structure of a conventional general brushless DC motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating shaft 2 bearings 2a to 2b bearings different examples 3 rotor yokes 3a to 3i rotor yokes different examples 4 rotor hubs 5 rotor magnets 5a to 5 rotor magnets different examples 7 housings 7a to 7b housings different examples 8 stator yokes 8a to 8g stator yokes different Example 9 Coil 10 Printed circuit board 11 Additional inertia 11a to 11c Another example of additional inertia 12 Stator holder 13 Shield cover 14 Protective cover 15 Rotor disk 31 Other rotor yoke 31a Other rotor yoke Other example 32 Additional ring yoke 32a Additional ring yoke Other example

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoru Akutsu 2-25 Sakaemachi, Koriyama City Mitsubishi Electric Corporation Koriyama Factory

Claims (14)

[Claims] 1. A rotary shaft supported by a base via a bearing, and a rotor magnet coupled to the rotary shaft and a first rotor.
And a stator on the base having a second facing portion at a position facing the first facing portion of the rotor, wherein at least one of the rotor and the stator is provided. A brushless motor, characterized in that one of the facing portions is formed to be inclined with respect to the axial direction of the rotary shaft. 2. The first opposing portion and the second opposing portion are both formed to be inclined with respect to the axial direction of the rotating shaft, and the inclination angles are equal to each other. Brushless motor. 3. The rotor has a first yoke and a second yoke, a rotor magnet is provided between the first yoke and the second yoke, and an end portion of the second yoke serves as a rotary shaft. The brushless motor according to claim 1 or 2, wherein the first facing portion is formed by inclining with respect to the axial direction. 4. The brushless motor according to claim 3, wherein the first yoke and the second yoke sandwich a rotor magnet in the axial direction of the rotating shaft. 5. The brushless motor according to claim 3, wherein the first yoke and the second yoke sandwich a rotor magnet in a direction orthogonal to the axial direction of the rotating shaft. 6. The brushless motor according to claim 1, wherein the rotor magnet is magnetized in a direction inclined with respect to the axial direction of the rotating shaft. 7. The brushless motor according to claim 1, wherein the rotor magnet is magnetized in a direction orthogonal to the axial direction of the rotating shaft. 8. The brushless motor according to claim 1, wherein the rotor magnet is magnetized in the same direction as the axial direction of the rotating shaft. 9. The rotor magnet is magnetized to have polar anisotropy.
Alternatively, the brushless motor according to item 5. 10. The stator according to claim 1, further comprising a stator yoke in which a plurality of magnetic plates are overlapped with each other to form a second facing portion that is inclined with respect to the axial direction of the rotating shaft. ~ 8 or 9 brushless motor. 11. The stator comprises: stacking a plurality of magnetic plates having different sizes in the axial direction of the rotating shaft,
The brushless motor according to claim 10, wherein the second facing portion is inclined with respect to the axial direction of the rotating shaft. 12. The brushless motor according to claim 10, wherein the stator is formed by stacking a plurality of magnetic plates and secondarily processing the ends of the magnetic plates to incline the second facing portion. 13. The brushless motor according to claim 1, wherein at least one of the first and second facing portions has a step portion and faces the other facing portion. 14. The brushless motor according to claim 1, wherein the stator is provided in an arc shape on an outer peripheral portion of the rotor.