JPH0116100B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a commutatorless motor having a permanent magnet in its rotor.

An example in which a conventional commutatorless motor is used to drive a vertical player is shown in FIG. 1a. In the same figure, 1
2 is a permanent magnet having multiple poles and serves as a main magnetic flux source, and 2 is a stator yoke made of a soft magnetic material. A rotor disk 3 is made of a soft magnetic material and holds the permanent magnet 1. The armature winding 12 is composed of a plurality of windings 12A to 12D, each of which is arranged on the stator yawter 2 as shown in FIG. 1b. 12A,
12B constitutes the first phase winding of a two-phase motor and is connected in series. 12C and 12D are also connected in series to form the second phase winding, and the electrical angle between the first and second phases is
They are arranged to have a 90° phase difference. In Figure 1, the permanent magnet has eight poles, and the angle between the coil sides of one winding is 45°, and the angle between the coil sides of adjacent windings is
It is 22.5°. These windings are supplied with a sinusoidal current having the same peak value and in phase with the induced voltage, and when the rotation speed is constant, the output torque of the motor is controlled to be constant at any position in the rotational phase of the rotor. shall be taken as a thing. The rotor disk 3 is fixed to the rotating shaft 9 via a support fitting 4, and a turntable 10 is fixed to the side opposite to the motor by a mounting fitting 11. The bearings 5 and 6 are now made of oil-less metal, for example, and are fixed to a shaft fitting 7 and further fixed to a support plate 8.

Now, in the device configured as described above, when the rotating shaft receives driving force from the magnet 1 attached to the rotor disk 3 and rotates, the bearings 5 and 6 are connected to the rotor of the motor and the turntable 10. Subject to radial load due to weight such as. At the same time, due to the attractive force between the permanent magnet 1 and the stator yoke 2, a thrust load is applied between the support fitting 4 and the side surface of the bearing 5. This thrust load increases as the attraction force of the magnet increases, and the load is particularly large when this load is received through surface contact. Even if this is changed to point contact, the structure is not necessarily simple and the thrust load remains. However, as the rotor magnet 1 rotates, alternating and rotating magnetic fluxes pass through the stator yoke 2, causing iron loss, that is, hysteresis loss, and eddy current loss. This loss occurs only as the rotational speed increases, and although it is small in the case of the player shown in FIG. 1, the loss cannot be ignored with other high-speed rotational loads. As described above, in the conventional permanent magnet rotating type non-commutator machine, the load increases due to the attractive force between the rotor and the stator, and unnecessary core loss occurs, which is not desirable.

The present invention has been made in view of the above points, and aims to embody an efficient commutatorless motor that eliminates the load and iron loss due to attraction force in principle. Furthermore, in conventional motors, it was not easy to make changes in the magnetic flux interlinking with the armature windings as they rotated into a sinusoidal distribution, but with the present invention, it is possible to easily make the change into a sinusoidal distribution. That is. The present invention will be explained below with reference to the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention, and in this figure, the same or corresponding parts as in FIG. 1 are designated by the same reference numerals. The armature winding 12 is sandwiched between nonmagnetic plates 13 and 14, for example, plates on which a wiring pattern is printed. Furthermore, the non-magnetic spacer rings 15 and 16 have the same thickness as the winding 12, and are integrated with the mounting plate 8 by the spacer 17.
Fixed. The yoke plate 2 is fixed to a support fitting 4. In other words, it becomes a part of the rotor, and the permanent magnet 1, yoke plate 2, and rotor plate 3 are integrally fixed to the rotating shaft 9. Other structures are the same as in FIG. 1.
Here, the yoke plate 2 is constructed as shown in FIG. 3b.
In other words, it is made of a disc-shaped plate, with a slit 21 as shown in the figure cut in a portion corresponding to the boundary between the poles of opposing permanent magnets. If this slit 21 were not provided, the magnetic flux interlinking with the armature winding 12 placed between the permanent magnet 1 and the yoke plate 2 would be as shown by the dotted line in Figure 3a as the rotor rotates. The waveform becomes distorted from a sine wave. At this time, even if a sinusoidal current is passed through the armature winding in the same phase as the voltage, pulsating torque will occur when the rotational speed is constant, and the torque will not be constant. Therefore, by making slits 21 near the boundaries of each of the eight poles of the permanent magnet 1 as shown in Figure 3b to increase the magnetic resistance between each pole, a sine wave distribution as shown by the solid line in Figure 3a is created. Make it. In other words, the magnetic resistance near the end of the magnetic pole is increased and the magnetic flux density at that portion is lowered to create a sinusoidal waveform.
This shape can be adjusted by adjusting the opening angle θ of the slit 21. The main magnetic flux passing through the yoke plate 2 bypasses this slit 21 and passes through the third
A magnetic path is closed with the magnet 1 through a path as shown by the arrow in FIG. b. The slit 21 is not only made by simply punching a disc-shaped plate through it, but also by cutting the soft magnetic plate to make it thinner, or by sinking it with a press to reduce the distance between it and the permanent magnet 1. This can also be achieved by increasing the size. In short, any device may be used as long as it has a yoke that continuously changes the magnetic resistance created between it and the magnet 1 in the rotational direction of the rotor.

In the motor having the structure shown in FIG. 3 as described above, the magnetic attraction force between the permanent magnet 1 and the yoke plate 2 does not act between them and the stator because both constitute the rotor. , no thrust load is applied to the bearing 5. Therefore, the load will not be large. In addition, since the yoke plate 2 rotates together with the permanent magnet 1, and their relative positions remain unchanged regardless of the rotational position of the rotor, alternating and rotating magnetic fields hardly act, and almost no iron loss occurs. This loss occurs based on the magnetomotive force caused by the armature winding 12, but the amount is small. Furthermore, since the yoke plate 2 is provided with an element that increases magnetic resistance near the boundary between the poles of the opposing magnets 1, the change in the magnetic flux interlinking with the armature winding 12 with respect to rotation can be made sinusoidal, and the motor can perform rotation with almost no torque unevenness at constant rotation.

It is also effective to use a configuration as shown in FIG. 4, which is different from the one shown in FIG. 3b. The shaded area in FIG. 4a is depressed, and its circumferential AA cross section is configured as shown in FIG. 4b. In this way, the magnetic flux density is high near the center of the magnetic pole, and the rate of attenuation increases toward the ends.As a result, the magnetic flux distribution near the center of the winding can be made sinusoidal as the rotation angle changes.

FIG. 5a shows an example in which a means for speed detection is further added to the example of FIG. 2. Yoke plate 2
This is an example in which a ring-shaped disc 22 is attached to which a ring-shaped multipolar magnet 23 is attached.
A print pattern as shown at 33 in FIG. 5b is printed on the surface of the non-magnetic plate 13 on the stator side facing the magnet. The pole pitch of this pattern is made to substantially match that of the magnet 23. With this configuration, it is possible to induce alternating current in the pattern 33 at a frequency corresponding to the pole pitch and rotation speed of the multipolar magnet 23 as the rotor rotates, and this can be used as a rotational speed signal. In conventional motors, the basic rotor is only a permanent magnet and a plate to which it is attached, so even when installing this type of speed generator mechanism, it can only be installed in a manner that is restricted by the placement of the magnet 1. However, as in the present invention, since the yoke plate 2 through which the main magnetic flux passes is also made a part of the rotor, the speed generator mechanism can also be provided on the yoke plate, increasing the degree of freedom in the configuration of the motor. The mechanism of the speed generator is not limited to the example shown in FIG. 5, but it is also conceivable to cut slits at an even pitch on the outer peripheral edge of the yoke plate 2 and sandwich the slits between light projectors and receivers.

Incidentally, although everything has been omitted in the above explanation, means for detecting the position of the rotor is essential for this type of commutatorless motor. It is a means for detecting the relationship between the armature winding and the polarity of the magnetic flux of the permanent magnet interlinked therewith, and is usually provided on the stator side where the armature winding is placed. Although it is possible to directly observe the magnetic flux of the rotor magnet 1 with a Hall element, it is also possible to cut a slit in a portion of the yoke plate 2 and use a light emitter/receiver with the slit placed on the stator side to detect the difference in signal depending on the presence or absence of the slit. , or may be used as a position signal. The yoke plate 2 brought to the rotor side in this way is not only useful as a path for the main magnetic flux, but also as a means for detecting speed and position signals as described above.

As is clear from the above description, according to the present invention, as a result of using the rotor as the yoke plate through which the main magnetic flux passes, the thrust load due to the attractive force of the permanent magnet can be eliminated from the bearing. Furthermore, iron loss due to rotation can be extremely reduced. Furthermore, by processing the yoke plate to continuously change the magnetic resistance of the portion corresponding to each electrode of the main magnetic flux source with respect to the rotational direction of the rotor, the magnetic flux of the permanent magnet interlinks with the armature winding. Since the distribution of the rotor can be made to approximate a sine wave shape with respect to the rotation angle of the rotor, there is an effect such as reducing torque ripple during constant rotation.

Furthermore, since position detecting means and speed detecting means can be added to the yoke plate, there is no need to provide these means separately, and the structure of the motor becomes simple, resulting in a practical motor with many advantages.

[Brief explanation of drawings]

1a and 1b are block diagrams showing one embodiment of a conventional non-commutator motor, FIG. 2 is a block diagram showing one embodiment of the present invention, FIG. 3a is a characteristic diagram showing magnetic flux characteristics, and FIG. FIG. 3b is an explanatory diagram for explaining the yoke plate of FIG. 2, and FIGS. 4 and 5 are explanatory diagrams for explaining the embodiment of the present invention, respectively. In the figure, 1 is a permanent magnet, 2 is a yoke, 3 is a rotor disk, 4 is a support metal fitting, 5 and 6 are bearings, and 12
is the armature winding. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A driving armature winding provided on the stator;
A main magnetic flux source that is located on the rotor and is provided on one side of the drive armature winding with a predetermined space in between, and has a plurality of poles that supply magnetic flux that interlinks with the drive armature winding. , is provided on the other side of the driving armature winding with a predetermined space in between, and rotates integrally with the main magnetic flux source while receiving magnetic flux from the main magnetic flux source, and the driving armature winding As the magnetic flux interlinking with the rotor changes in the rotational circumferential direction of the rotor, the magnetic resistance of the portion corresponding to each pole of the main magnetic flux source increases depending on the drive current waveform of the drive armature winding. A commutatorless motor characterized by having a yoke that changes continuously with respect to the rotational direction of the motor. 2. The commutatorless motor according to claim 1, wherein the yoke also serves as position or speed means.