JPS6011543B2 - rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating electrical machine such as a motor with a frequency generator that can obtain a signal with a frequency corresponding to the rotational speed of a rotor.

In conventional rotating electrical machines of this type, such as motors with frequency generators, the drive unit that provides rotational force to the rotor of the motor and the frequency generator that detects the rotational speed of the rotor as a frequency signal have a separate structure. There were many.

As a result, the number of parts was large, the structure was complex, and manufacturing was difficult. In order to eliminate these drawbacks, for example, as seen in Japanese Tokusatsu No. 52-51512, a disc-shaped multipolar permanent magnet attached to the rotor and a drive coil arranged in the stator have been developed. A motor with a frequency generator in which a generator coil is placed between the two has been proposed.

However, such a structure has problems such as the permanent magnet and the drive coil being separated from each other, which reduces the efficiency of the motor, and also makes it difficult to use an annular permanent magnet.
The present invention solves such problems and provides a rotating electrical machine such as a frequency generator-equipped motor with a simple structure and high efficiency.

The present invention will be explained below with reference to illustrated embodiments. FIG. 1 is a block diagram of main parts of an embodiment of the present invention. In the figure, permanent magnets 2 attached to a rotor 1 are spaced at equal pitches (
90o) or an annular magnet with four poles attached at approximately equal pitch intervals. The armature iron "○3" arranged inside the rotor 1 is radially formed at equal pitch intervals (120o) or approximately approximately T protruding integrally at approximately equal pitch intervals.
It has letter-shaped protrusions 4a, 4b, and 4c made of magnetic material. One drive coil 5a, 5b, 5c is wound around each of the protrusions 4a, 4b, 4c.

In addition, auxiliary grooves 6a, 6a2, 6b,
, 6Q, 6c, , 6c2 are provided in parallel to the central axis 0 of the armature core 3, that is, in a direction perpendicular to the plane of the drawing.
, 6c. , 6c2 is provided with a large gap between the permanent magnet 2 and the protruding part. Further, in the auxiliary grooves 6a, 6a2, 60, 6Q, 6c, and 6c2, partial coils 7a, 7b, 7c forming the speed detection coil 7 are provided.
is wrapped. In addition, 8a, 8b, 8c in FIG.
is a groove (gap) between the projecting bodies 4a, 4b, and 4c. Here, the protrusions 4a, 4b, 4c are divided into three phases having a phase difference in relative positional relationship with the magnetic poles of the permanent magnet 2. Therefore, for example, if the rotational position of the permanent magnet 2 is detected by a magnetically sensitive element such as a Hall element, and the energized drive coil is controlled by a semiconductor switch such as a transistor, rotation in the same direction can be maintained. As such a control circuit, a well-known one for electronic commutator type motors can be used, so illustration and detailed description thereof will be omitted here. Next, the speed detection signal generated by the speed detection coil 7 will be explained with reference to FIG.

FIG. 2a shows the distribution of magnetic flux density BM on the surface of the permanent magnet 2, and FIG. 2b is a developed view showing the arrangement relationship of the protrusions 4a to 4c of the armature core 3. Partial coil 7 of speed detection coil 7
The voltages generated at a, 7b, and 7c are respectively ea, eb,
ec, the speed detection coil 7 obtains a generated voltage e (=ea+eb+ec) which is a combination of these. Assuming that the permanent magnet 2 is rotating at a constant angular velocity in the direction of the arrow shown in FIG. 2, and assuming the state shown in FIG. b. Three-phase generated voltages ea, eb, e with phase differences as shown in c
c occurs. As a result, the composite generated voltage e obtained from the speed detection coil 7 is as shown in FIG. 3d. That is, 1
A three-pulse frequency signal can be obtained for a rotation of the magnetic pole pair by an angle (180 degrees). If the frequency of the back electromotive force generated in each drive coil is 〆M, then ・3×Na,
It is a frequency signal of M. This frequency signal is used, for example, when controlling the rotational speed of the rotor 1 to a constant speed. Next, the cogging force of this embodiment will be considered, and the auxiliary groove 6a
, ~6c2 will be explained.

Generally, cogging force is generated when the magnetic energy stored in the space between the permanent magnet 2 and the armature core 3 changes depending on the rotational position of the permanent magnet 2. Since magnetic energy is a quantity related to the square of the magnetic flux density, the permanent magnet 2 has a magnetic fluctuation of its harmonic component with one magnetic pole pitch (90 degrees) as a fundamental period. Therefore, 1
With the magnetic pole pitch (90o) as the basic period, the armature core 3
It is only necessary to consider the magnetic fluctuation component of , and if the resultant fluctuation component is reduced, the cogging force will be reduced. Magnetic fluctuations in the armature core 3 are caused by grooves 8a to 8 between the protrusions 4a, 4b, and 4c.
c and auxiliary grooves 6a, 6a2, 6b, 6Q, 6c, 6
Caused by c2. FIG. 4 shows magnetic fluctuations due to each of these grooves. FIG. 4a shows magnetic fluctuations due to the grooves 8a, 8b, 8c between the protrusions 4a, 4b, 4c. If groove 8a is taken as a reference, groove 8b has a phase difference of 1/3 of one magnetic pole pitch, and groove 8c has a phase difference of 2/3 of one magnetic pole pitch. FIG. 4b shows the magnetic fluctuations caused by the auxiliary grooves 6a, 6b, 6c. Similarly, auxiliary grooves 6a2, 6b2
, 6c2 is shown in FIG. 4c. Therefore, the magnetic fluctuation of the armature iron 03 in the embodiment shown in FIG. 1 is shown in FIG. 4 d, which is a combination of FIGS. 4 a, b, and c. Add this to the auxiliary grooves 6a, 6a2, 6b, 6Q, 6C, 6C2.
If compared with FIG. 4a, which shows the magnetic fluctuation when no magnetic field is provided, the pitch of the fluctuation is shorter (the frequency becomes higher-order), and the amount of fluctuation is also 4.0 times smaller. the result,
The cogging force in this embodiment is small. As shown in this embodiment, if the speed detection coil is provided using the auxiliary groove provided on the protrusion of the armature core, the number of parts can be reduced and a motor with a frequency generator with a simple structure can be obtained.

Moreover, since the speed detection coil winds a part of the protrusion of the armature core, the magnetic flux interlinking with the speed detection coil becomes large.

As a result, a detection frequency signal with a large amplitude can be obtained, which is advantageous for signal processing for constant speed control and the like. Furthermore, since the gap between the armature core protrusion and the permanent magnet can be set small, the efficiency of the electric motor can be improved. In this embodiment, the frequency of the detection frequency signal obtained from the speed detection coil 7 is set to
The frequency of the back electromotive force generated at 5c was set to three times the frequency N.

Generally, the frequency of the speed detection signal can be made an odd number times the frequency of the back electromotive force. That is, 〆M=(2h
+1)・Na,M (where m is an integer of 1 or more).

In this way, by increasing the detection frequency, control characteristics can be improved. Furthermore, regarding the relative positional relationship with the magnetic poles of the permanent magnet 2, the protrusions 4a to 4c of the armature core 3 are
The magnetic fluctuation due to the grooves 8a to 8c between the auxiliary grooves 6a,
, 6a2, 6b, 6Q, 6c, , 6c2, if the magnetic fluctuations are offset and reduced,
An electric motor with small cogging force can be obtained. In addition,
In the above-described embodiment of the present invention, a three-phase drive system using three drive coils that are independent in their relative position to the permanent magnet has been described, but the present invention is not limited to such a system. Generally, it is applicable to multi-phase drive systems.

Furthermore, the shape, number, and arrangement of the protruding bodies and auxiliary grooves are not limited to those of the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Further, the armature core used in the present invention is not limited to a laminate of silicon steel plates, and may be formed by bending iron plates.

Furthermore, the present invention is not limited to the abduction type as in the illustrated embodiment;
It goes without saying that an adductor type can also be used and is included in the present invention.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of main parts of an embodiment of the present invention, Fig. 2 a and b
3 is a diagram showing the distribution of magnetic flux density on the surface of the permanent magnet and a developed diagram showing the arrangement relationship of the protrusions of the armature core in the same example.
Figures a, b, c, and d are voltage waveform diagrams of various parts obtained in the same example, and Figure 4 a, a, c, and d are magnetic fluctuations for explaining the effects of the auxiliary groove in the same example. FIG. 1... - Evening, 2...Permanent magnet, 3...Armature core, 4a, 4b, 4c...Magnetic body projecting body, 5a, 5b
, 5c... Drive coil, 6al, 6a2, 60
,6b2,6c,,6c...auxiliary groove,7...
-Speed detection coils, 7a, 7b, 7c... partial coils, 8a, 8b, 8c... grooves. Figure 4 Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A rotor having a plurality of permanent magnets magnetized with multiple poles at equal pitch intervals or approximately equal pitch intervals, and a plurality of approximately T-shaped magnets facing the magnetized surfaces of the permanent magnets. an armature core having a body-made protrusion, a drive coil wound around each of the magnetic body protrusions, and a speed detection coil for obtaining a signal with a frequency corresponding to the rotational speed of the rotor; A plurality of auxiliary grooves having a shape such that the gap between the magnetic body and the permanent magnet is large is provided in a required portion of the magnetic body projecting body facing the permanent magnet, and the auxiliary groove portion is provided with a plurality of auxiliary grooves that are shaped so as to increase the gap between the magnetic body and the permanent magnet. The speed detection coil is constructed by winding a plurality of partial coils that generate multi-phase power generation voltages having a phase difference of equal pitch or approximately equal pitch, and connecting the partial coils in series. Rotating electric machine. 2. In the statement of claim 1, when the frequency of the generated voltage generated in the speed detection coil is f_D, and the frequency of the back electromotive force generated in the drive coil is f_M, f_D=(2m+1)f_M (wherein , m is an integer of 1 or more).