JPS60257754A - Magnet rotary type motor - Google Patents

Abstract

PURPOSE:To enhance the various properties of a motor by detecting the rotary position of a rotor by the second magnet provided in a recess formed of a yoke and a cylinder, thereby obivating an erroneous detection due to the leakage magnetic flux from a winding. CONSTITUTION:A cylindrical yoke 3 is increased in length as compared with the first magnet 4, the inner periphery of a cylinder 11 is partly engaged fixedly with the longer outer periphery, the second magnet 12 is so disposed fixedly to become plural poles in a recess formed of the bottom 3a of the yoke and the inner periphery of the cylinder 11 in an axial peripheral direction, and the magnet 12 is opposed to a sensor 7. With this construction, since the magnetic flux emitted from the magnet 12 is detected by the senor 7,the sensor 7 can be disposed at the position which is not affected by the leakage magnetic flux from a winding as designated by an arrow, thereby effectively detecting the rotary position of the rotor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnet rotating type electric motor used in so-called industrial and general households. BACKGROUND OF THE INVENTION Electric motors have come to be widely used as industrial and household motors.Hereinafter, a conventional magnet rotation type electric motor will be described with reference to the accompanying drawings.

In FIG. 1, 1 is a rotating shaft, 2 is a rotor in which a first magnet 4 is arranged and fixed in an annular manner so as to form multiple poles in the circumferential direction of the rotor 2 via a yoke 3, and 5 is a rotor in the outer circumferential direction of the rotor 2. 6 is a winding inserted into a slot provided in the stator; 7 is a sensor for detecting the rotational position of the rotor 2; 8 is a sensor for detecting the rotational position of the rotor 2; 51/ilX A control circuit for generating a rotating magnetic field, 9 a bearing, and 10 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, in response to the signal from the sensor 7, the control circuit 8 generates an optimum rotating magnetic field σ in the stator 5, and the rotor 2 rotates. However, the sensor 7 will not operate unless the sensor 7 detects a magnetic flux higher than a certain magnetic flux density. There is no trilx unless the cast is 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, posing the problem that a St 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 rotary shaft, a rotor having first magnets arranged and fixed in an annular shape so as to form a plurality of poles in the circumferential direction of the shaft via a yoke, and a first magnet arranged and fixed in the circumferential direction of the rotor. A stator provided with an air gap, a winding inserted into a slot provided in the stator, a sensor for detecting the rotational position of the rotor, and a rotating magnetic field generated in the stator in response to a signal from the sensor. σ, the yoke is made longer in the axial direction than the first magnet, and a part of the inner peripheral surface of the cylindrical body is fitted and attached to the longer outer peripheral surface,
By arranging and fixing second magnets to the four parts formed by the bottom surface of the yoke and the inner circumferential surface of the cylindrical body so as to form multiple poles in the circumferential direction of the shaft, the influence of magnetic flux leakage from the windings can be eliminated. 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 FIGS. 2 to 7, parts that are the same as those in the conventional example are given the same reference numerals, and the description thereof will be omitted. 11
A second magnet is arranged and fixed to the cylindrical body 12 made of a magnetic or non-magnetic material so as to form a plurality of poles in the axial circumferential direction. Instead, in FIG. 2, the cylindrical yoke 3 is made longer in the axial direction than the first magnet 4, and a part of the inner circumferential surface of the cylindrical body 11 is fitted and fixed to the outer circumferential surface of this longer one. A second magnet 12 is arranged and fixed in a recess formed by the yoke bottom 3a and the inner circumferential surface of the cylindrical body 11 so as to have multiple poles in the axial direction, and the magnet 12 is opposed to the sensor 7. ing. In the above configuration, since the sensor 7 detects the magnetic flux emitted from the second magnet 12, the sensor 7 can be placed and fixed at a position where it is not affected by the leakage magnetic flux from the winding as shown by the arrow. , the rotational position of the rotor 2 can be detected reliably.

Since the twisted second magnet 12 is disposed and fixed on the yoke bottom surface 3a which is longer than the stator end surface 5a in the axial direction, it does not function as a magnetic field for the rotation of the rotor 2. Therefore, the rotor 2 is rotated by the magnetic field obtained by the first 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, and the optimum field is applied to the stator 5. It becomes possible to generate all the magnetism, 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 loads.

Furthermore, in this embodiment, the cylindrical body 11 can be easily fixed by simply fitting and fixing the cylindrical body 11 to the yoke 3, for example, by press-fitting, and the yoke 3 can also serve as the yoke of the first magnet 4 and the second magnet 12. In addition, since the cylindrical body 11 constitutes the housing of the second magnet 12, the cylindrical body '11 receives the centrifugal force of the second magnet 12's own weight as the rotor rotates. I am not affected by this.

Next, by making the cylindrical body 11 non-magnetic, 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 magnetic. It does not affect the detection and makes the first detection more reliable.
The rotor 2 can be rotated σ only by the magnetic field of the magnet 4.

As shown in FIGS. 3 and 4, the fitting portion 112L of the cylindrical body 11 with the outer peripheral surface of the yoke and the other portion 11b do not have to be equal in diameter, It is sufficient if the sensor can reliably detect the emitted magnetic flux. For example, if the outer diameter of the yoke 3 is small, the second magnet 12 is arranged and fixed inside the outer diameter of the yoke 3, and the sensor 7 is arranged at a position where the magnetic flux emitted from the second magnet 12 can be detected. If it is structurally difficult to install and fix the yoke, as shown in Fig.
The rotational position of the rotor 2 can be detected more reliably if the sensor 7 is easily attached. On the other hand, if the outer diameter of the yoke 3 is large and there is no need for the outer diameter of the second magnet 12 to be as large as the outer diameter of the yoke, as shown in FIG. The diameter of the other portion 11b is made smaller than the diameter of the fitting portion 11a.
By doing so, the amount of the second magnet 12 is reduced, and at the same time, the strength of the cylindrical body 11 against centrifugal force due to the rotation of the rotor 2 is increased. Essentially, if the sensor 7 can reliably detect the rotational position of the rotor 2, the fitting portion 11a of the cylindrical body 3 with the yoke outer peripheral surface
The diameter of the other portion 11b may be different from the diameter σ of the other portion 11b.

As shown in FIG. 5, at least one convex portion 11C is formed on the lower inner circumferential surface of the cylindrical body 11 that does not contact the yoke.
By providing this, the positioning of the second magnet 12 with respect to the first magnet 4 becomes reliable and easy, and the detection of the rotational position of the rotor 2 by the sensor 7 becomes very accurate.

As shown in FIG. 6, the second magnet 12 is positioned with respect to the first magnet 4 by providing a small recess 12C on the outer peripheral surface of the second magnet 12, which corresponds to the convex part 11c of the cylindrical body 11. It's even easier, more reliable, and more reliable. In addition,
The positional relationship between the convex portion 11c and the concave portion 120 may be reversed.

As shown in FIGS. 7 and 8, at least one convex portion 11d is provided on the first magnet 4 side with respect to the axial direction of the cylindrical body 11, and the cylindrical body of the first magnet 4 is 11 (lull f/i: by providing the concave portion 4d so as to fit with the convex portion 11d, the second
The positioning of the magnet 12 becomes very easy and accurate. Note that the positional relationship between the convex portion 11 (i and the fourth portion 4d may be reversed). From the above, the detection of the rotational position of the coater 2 by the sensor becomes accurate and highly reliable, and it is possible to provide a magnet-rotating motor with high efficiency even under high loads.

As is clear from the embodiments showing the effects of the invention, in the magnet-rotating electric motor of the present invention, the rotational position of the rotor is detected by the second magnet provided in the recess formed by the yoke and the cylindrical body. Seventh company,
Leakage from the windings and erroneous detection due to magnetic flux are eliminated, the motor characteristics can be improved, and efficiency is high under 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 yoke outer peripheral surface can be changed depending on the structure of the motor. This makes it easier to attach the sensor6, and there is at least one convex part or four parts on the inner circumferential surface of the cylindrical body that does not come into contact with the yoke, or on the surface that fits with the first magnet in the axial direction. By providing four parts or convex parts on the first magnet and the second magnet corresponding to the convex parts or concave parts, the positioning of the second magnet with respect to the first magnet is easy and reliable. Therefore, the rotational position detection of the rotor becomes highly reliable.C.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an example of a conventional magnet-rotating motor, FIG. 2 is a vertical cross-sectional view showing a first embodiment of the magnet-rotating motor of the present invention, and FIG. FIG. 4 is a vertical cross-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. A rotor cross-sectional view of a fifth embodiment of the present invention,
7 is a partially exploded perspective view of a rotor according to a sixth embodiment of the present invention, and FIG. 8 is a perspective view of the rotor of FIG. 7. 4-・First magnet, A・Sensor, 11・・Cylindrical body, 12 Second (magnet, 4d, 11(1・・Four parts and convex part of the fitting tRi of the first magnet and cylinder body, 11C - Inner circumference of cylinder [1'I (llI convex part, 12C...second
Four parts of the magnet. Name of substitute Patent attorney Toshio Nakao and 1 other person No.1
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] (1) A rotating shaft, a rotor having first magnets arranged and fixed in an annular shape so as to form multiple poles in the circumferential direction of the shaft via a yoke;
A stator provided with a gap in the outer circumferential direction, a winding inserted into a slot provided in this stator, a sensor that detects the rotational position of the rotor, and a signal from this sensor. A control circuit correspondingly generates a rotating magnetic field in the stator, and the yoke is made longer in the axial direction than the first magnet (IC, the longer outer circumference m1
A cylindrical body is fixed to the cylindrical body, and a plurality of second poles are arranged in the axial circumferential direction on the four parts formed by the bottom surface of the yoke and the inner peripheral surface of the cylindrical body.
A magnet-rotating electric motor in which a magnet is placed facing the sensor. (2) The magnet-rotating electric motor 3 according to claim 1, wherein the cylindrical body has a diameter that is different between the fitting part with the yaw outer circumferential surface and the other parts. A magnet rotating electric motor according to claim 1 or 2, wherein the body is a non-magnetic material. (4) The magnet rotating electric motor according to claim 1 or claim 3, wherein the cylindrical body has at least one convex portion or concave portion on its inner circumferential surface. , (5)
5. The magnet rotating electric motor according to claim 4, wherein the second magnet is provided with at least one concave or convex portion on its outer peripheral surface. (6) A recess is formed on the joint surface between the cylindrical body and the cylindrical body of the first magnet. A magnet rotating electric motor according to claim 4 or 5, which is provided with a convex portion.