JPH0452064B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnet rotary electric motor used in so-called industrial and household applications.

Conventional structure and its problems In recent years, this type of magnet rotating electric motor has been used for industrial,
They have also come to be widely used as motors for general household use. Hereinafter, a conventional magnet rotating electric motor will be described with reference to the accompanying drawings.

In FIG. 1, 1 is a rotating shaft, and 2 is a first electrode arranged in an annular shape through a yoke 3 to form multiple poles in the radial direction.
5 is a stator provided with a space in the outer circumferential direction of the rotor 2;
7 is a sensor that detects the rotational position of the rotor 2; 8 is a control circuit that generates a rotating magnetic field in the stator 5 in response to a signal from the sensor 7; 9
is a bearing, and 10 is a bracket.

In the above configuration, the sensor 7 detects leakage magnetic flux emitted from the first magnet 4 and detects the rotational position of the rotor 2. Then, the control circuit 8 generates an optimum rotating magnetic field in the stator 5 in response to the signal from the sensor 7, and the rotor 2 rotates. However, since the sensor 7 does not operate unless it detects magnetic flux above a certain magnetic flux density, in order to detect the rotational position of the rotor 2, the sensor 7 must be placed within a certain distance from the end of the rotor 2. Must be fixed. However, leakage magnetic flux is also generated from the winding 6 as indicated by the arrow in the figure. This leakage magnetic flux depends on the winding current, and if it exceeds a certain value, it will interfere with the detection of the rotational position of the rotor 2, causing the problem that a large load cannot be applied to the motor.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned problems, and provides a magnet-rotating electric motor that can reliably detect the rotational position of the rotor and achieve high efficiency even under high loads.

Structure of the Invention The magnet rotating electric motor of the present invention includes a rotor in which a first magnet is arranged and fixed in an annular manner so as to form a plurality of poles in the radial direction via a yoke on a rotating shaft, and an air space is provided around the outer periphery of the rotor. A stator provided through the stator, a winding inserted into a slot provided in the stator, a sensor that detects the rotational position of the rotor, and a control circuit that generates a rotating magnetic field in the stator in response to a signal from the sensor. one end of the yoke extends in the axial direction beyond one end of the first magnet, and a cylindrical body is fitted to the outer peripheral surface of the extended yoke, so that one end surface of the yoke and the A second magnet is disposed facing the sensor so as to have multiple poles in the axial direction in the recess formed by the inner peripheral surface of the cylindrical body, thereby eliminating the influence of leakage magnetic flux of the winding on the sensor. This makes it possible to maintain high efficiency even under high loads.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In Figures 2 to 7,
Components that are the same as those in the conventional example are designated by the same reference numerals, and the description thereof will be omitted here. 11 is a cylindrical body made of a magnetic or non-magnetic material, and 12 is a second magnet arranged and fixed so as to have multiple poles in the axial direction in the opposite direction to the first magnet 4.
, and the cylindrical yoke 3 has one end connected to the first
The yoke 3 extends in the axial direction from the magnet 4 and one end 5a of the stator 5, and a part of the inner circumferential surface of the cylindrical body 11 is fitted and fixed to the outer circumferential surface of the extended yoke 3. A second magnet 12 is arranged and fixed in a recess formed by one end surface 3a of the yoke and the inner peripheral surface of the cylindrical body 11 so as to have a plurality of poles in the axial direction. is facing. With the above configuration, the sensor 7 detects the magnetic flux emitted from the second magnet 12, so the sensor 7 can be arranged and fixed at a position where it is not affected by the leakage magnetic flux from the winding shown by the arrow. Then,
The rotational position of the rotor 2 can be detected reliably. Further, the second magnet 12 is located at one end 5a of the stator.
One end surface 3a of the yoke 3 extending in the axial direction
Since the rotor 2 is placed and fixed on the top, it does not work as a field magnet for the rotor 2 to rotate.
It does not affect the rotation of the Therefore, the first
The rotor 2 is rotated by the magnetic force obtained by the second magnet 4, and the sensor 7 detects the magnetic flux obtained by the second magnet 12 to detect the rotational position of the rotor 2.
It becomes possible to generate an optimum magnetic field in the stator 5, and it is possible to provide a magnet rotating electric motor that can reliably detect the rotational position of the rotor and is highly efficient even under high load.

Furthermore, in this embodiment, the cylindrical body 11 can be easily fitted and fixed to the yoke 3 by, for example, press fitting, and the yoke 3 is connected to the first magnet 4 and the second magnet 1.
Since the cylindrical body 11 can also serve as the second yoke, and the housing of the second magnet 12 is constituted by the cylindrical body 11, the cylindrical body 11 receives the centrifugal force of the second magnet 12's own weight as the rotor rotates, and the rotor It is not affected in any way by the rotation of.

Furthermore, by making the cylindrical body 11 a non-magnetic material, the leakage magnetic flux coming out of the winding 6 becomes more difficult to pass through the cylindrical body 11 than when the material of the cylindrical body is a magnetic material. The rotor 2 can be more reliably rotated only by the magnetic force of the first magnet 4 without affecting the detection of the magnet 7.

3 and 4 show the second and third embodiments,
This allows the sensor 7 to reliably detect the magnetic flux emitted from the second magnet 12. For example, because the outer diameter of the yoke 3 is small, it may be difficult to arrange and fix the second magnet 12 inside the outer diameter of the yoke 3, or the magnetic flux emitted from the second magnet 12 may be detected. If it is structurally difficult to arrange and fix the sensor 7 in a possible position, the diameter of the installation part 11b of the second magnet 12 is made larger than the diameter of the yoke, as shown in FIG. If the sensor 7 is installed at a position where magnetic flux can be easily detected, the rotational position of the rotor 2 can be detected reliably. On the other hand, if the outer diameter of the yoke 3 is large and the outer diameter of the second magnet 12 is not required to be as large as the outer diameter of the yoke 3, as shown in FIG. If the diameter of the second magnet placement part 11b is made smaller than the diameter of the fitting part 11a with the surface, the second magnet 1
2 can be made smaller, and the rotor 2 can be made smaller.
The strength of the cylindrical body 11 against centrifugal force due to rotation can also be increased. In short, as long as the sensor 7 can reliably detect the rotational position of the rotor 2, the diameter of the fitting portion 11a of the cylindrical body 11 with the yoke outer peripheral surface and the diameter of the disposed portion 11b of the second magnet 12 may be different. It is something.

5 to 8 show the first magnet 4 and the second magnet 12.
This shows an embodiment of a structure that facilitates mutual positioning of the cylindrical body 1 and 2, as shown in FIGS.
At least one convex portion 11c is provided on the inner circumferential surface of the disposed portion 11b of the second magnet 12, and at least one convex portion 11c is provided on the inner circumferential surface of the cylindrical body 11 on the outer circumferential surface of the second magnet 12. Recessed portion 12c that engages with portion 11c
is provided to eliminate movement by positioning the cylindrical body 11 and the second magnet 12 and by slipping during rotation. Further, as shown in FIGS. 7 and 8, at least one convex portion 11d is provided at the end of the cylindrical body 11 on the first magnet 4 side, so that the cylindrical body 11 of the first magnet 4 A concave portion 4d that engages with the convex portion 11d is provided on the abutting surface to prevent positioning of the first magnet 4 and the cylindrical body 11 and to prevent movement during rotation. With the above configuration, the first magnet 4 and the second
positioning with the magnet 12 becomes easy, the rotational position detection of the rotor 2 by the sensor 7 becomes accurate and highly reliable, and it is possible to provide a highly efficient magnet-rotating electric motor even under high loads. It is.

Effects of the Invention As is clear from the above embodiments, the magnet rotating electric motor of the present invention detects the rotational position of the rotor using the second magnet provided in the recess formed by the yoke and the cylindrical body. Erroneous detection due to magnetic flux leakage from the windings is eliminated, various characteristics of the motor can be improved, and efficiency is increased at high loads.

Note that if the cylindrical body is made of a non-magnetic material, the influence of the second magnet on the stator will be eliminated, and the diameter of the other cylindrical body relative to the diameter of the fitting part of the cylindrical body with the outer peripheral surface of the yoke can be adjusted depending on the structure of the motor. By changing the length, the sensor can be easily installed. At least one convex portion or concave portion is provided on the inner circumferential surface or the end portion of the second magnet arrangement portion of the cylindrical body, and the first
By providing the second magnet with a concave portion or a convex portion corresponding to the convex portion or concave portion, the second magnet can be easily and reliably positioned with respect to the first magnet, and the rotational position of the rotor can be adjusted easily. Detection becomes more reliable.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing an example of a conventional magnet-rotating electric motor, FIG. 2 is a longitudinal cross-sectional view showing a first embodiment of the magnet-rotating electric motor of the present invention, and FIG. FIG. 4 is a longitudinal sectional view of the rotor of the third embodiment of the present invention, FIG. 5 is a perspective view of the cylindrical body of the fourth embodiment of the present invention, and FIG. 6 is the rotor of the third embodiment of the present invention. A cross-sectional view of a rotor according to a fourth embodiment of the invention, FIG. 7 is a partially exploded perspective view of a rotor according to a fourth embodiment of the invention,
FIG. 8 is a perspective view of the rotor of FIG. 7. DESCRIPTION OF SYMBOLS 1...Rotating shaft, 3...Yoke, 4...First magnet, 5...Stator, 6...Winding, 7...Sensor, 8...Control circuit, 11...Cylindrical body, 12...
Second magnet, 4d, 11d...Concavities and protrusions on the fitting surface of the first magnet and cylindrical body, 11c...Protrusion on the inner peripheral surface side of the cylindrical body, 12c...Concavity of the second magnet .

Claims (1)

[Claims] 1. A rotor in which first magnets are arranged and fixed in an annular manner so as to form a plurality of poles in the radial direction on a rotating shaft via a yoke, and a stator provided on the outer periphery of the rotor via a space. and a winding inserted into a slot provided in the stator, a sensor that detects the rotational position of the rotor, and a control circuit that generates a rotating magnetic field in the stator in response to a signal from the sensor, One end of the yoke extends in the axial direction beyond one end of the first magnet, and a cylindrical body is fitted onto the outer peripheral surface of the extended yoke, so that one end surface of the yoke and the inner periphery of the cylindrical body A magnet rotation type electric motor, wherein a second magnet is disposed in a recess formed by a surface and a second magnet facing the sensor so as to have a plurality of poles in the axial direction. 2. The magnet-rotating electric motor according to claim 1, wherein the cylindrical body is formed so that the diameter of the fitting part with the outer peripheral surface of the yoke and the part where the second magnet is disposed are different. 3 Claim 1 in which the cylindrical body is a non-magnetic body
The magnet rotating electric motor according to item 1 or 2. 4. Providing uneven portions that engage with each other on the abutting surface between one end of the cylindrical body and the cylindrical body of the first magnet,
The magnet according to any one of claims 1 to 3, further comprising a concavo-convex portion that engages with each other at the joint between the inner circumferential surface of the cylindrical body and the outer circumferential surface of the second magnet. Rotary electric motor.