JPH01194843A - Motor rotor - Google Patents

Abstract

PURPOSE:To reduce a centrifugal force, to improve a strength in the centrifugal direction and to prevent a magnet from coming off, by forming a permanent magnet into a ring-shaped body and by fitting said magnet to a rotating shaft. CONSTITUTION:A rotor body 14 composed of a ring-shaped permanent magnet 12 and an L-shaped rotor yoke 13 is provided and fixed to a rotating shaft 7. Said rotor yoke 13 is brought into contact with the end face of said permanent magnet 12 and is composed of a fan-shaped fitting part 15 and a cover part 16 bent perpendicularly to cover the outer peripheral face of the permanent magnet 12. When the motor is operated, the rotor body 14 rotates integrally with the rotating shaft 7 and a centrifugal force works on said permanent magnet 12 and rotor yoke 13. However, the centrifugal force working on said permanent magnet 12 becomes smaller, since the magnet 12 is fitted to the rotating shaft 7. Also, the strength of the permanent magnet 12 in the centrifugal direction is improved, as the magnet 12 is ring-shaped. Therefore, even if the motor is operated at high speed, the permanent magnet 12 can be prevented from coming off.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a rotor for an electric motor.

2. Description of the Related Art A typical structure of a conventional electric motor is shown in FIG. First, in the approximate center of the motor frame 1, a rotor 3 is rotatably held by a pair of bearings 2, and a stator 6 consisting of a cylindrical core 4 and a coil 5 wound around the core 4 is installed. It is fixed to the motor frame 1 surrounding the rotor 3.

Next, the rotor 3 has a rotating shaft 7 as shown in FIG.
The rotor yoke 8 has a cylindrical shape and a permanent magnet 9 has a circular arc shape.

Further, as shown in FIG. 5, a permanent magnet 10 for generating rotational pulses is fixed to one end of the rotating shaft 7.
A magnetic detection element 11 arranged on the outer periphery of the motor frame 1 is fixed to the motor frame 1 .

Problems to be Solved by the Invention When an electric motor is operated at high speed, a large centrifugal force acts on the permanent magnet 9 that is bonded to the rotor yoke 8, and there is a risk that the bonded permanent magnet 9 may separate from the rotor yoke 8. There is.

In addition, the shape of the rotor 3 is determined by the shape of the permanent magnet 9, making it impossible to accommodate various electric motors with different performances.

Furthermore, if the number of field poles in the rotor is small, uneven rotation occurs, causing vibration and noise.

Moreover, the permanent magnet 10 for generating rotational pulses is placed at 7 within the rotation center.
In order to provide the installation space within the motor frame 1, the electric motor becomes large in size.

Means for Solving the Problems A rotor body consisting of a ring-shaped permanent magnet and a pair of rotor yokes with an angled cross-section is provided, and this rotor body is mounted on a rotating shaft. Further, a plurality of rotor bodies are provided, and these rotor bodies are stacked on the rotating shaft. Furthermore, when the rotor bodies are stacked on the rotating shaft, they are stacked in a spiral shape. moreover,
A magnetic detection device is provided in the thrust direction of the end face of the rotor yoke.

action When the rotor body rotates as the motor operates.

As the centrifugal force acting on the permanent magnet decreases, its strength in the centrifugal direction increases. Furthermore, by stacking multiple rotor bodies, it is possible to construct various electric motors with different magnetic field strengths, and by stacking the rotors in a spiral shape, even when the number of field poles is small, it can rotate. Unevenness is prevented.

Further, the magnetic detection device detects rotational pulses emitted from the end face of the rotor yoke as the electric motor operates, and detects the rotational speed of the electric motor.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 and 2. Incidentally, the same parts as those explained in FIGS. 5 and 6 are indicated by the same reference numerals, and the description thereof will be omitted. first,
A rotor body 14 is provided, which is made up of a ring-shaped permanent magnet 12 and a pair of rotor yokes 13 having a cross section arranged on both sides of the permanent magnet 12. This rotor body 14 is fixed on the rotating shaft 7. There is. Here, the rotor yoke 13 has a mounting portion 15 that is in contact with the end surface of the permanent magnet 12 and is formed in a substantially fan shape, and a mounting portion 15 that is bent in a substantially perpendicular direction from the fan-shaped outer periphery of the mounting portion 15,
2, and a cover portion 16 that covers the outer circumferential surface of 2.

Next, a magnetic detection element 17, which is a magnetic detection device, is attached to a portion of the inner circumferential surface of the motor frame 1 that faces the end surface of the mounting portion 15.

In such a configuration, when the electric motor is operated, the rotor main body 14 rotates integrally with the rotating shaft 7, and centrifugal force acts on the permanent magnets 12 and the rotor yoke 13. However, since the permanent magnet 12 is attached to the rotating shaft 7, the centrifugal force acting on the permanent magnet 12 is small, and
Since the permanent magnet 12 has a ring shape, its strength in the centrifugal direction is improved.

Further, rotation pulses accompanying the operation of the electric motor are outputted from the end face of the mounting portion 15 facing the magnetic detection element 17, and the rotation speed of the electric motor can be detected by reading these rotation pulses. Here, when detecting the rotational speed of the electric motor, there is no need to provide a permanent magnet for generating rotational pulses on the rotating shaft 7 as in the conventional example, and the electric motor can be miniaturized.

Next, a second embodiment of the present invention will be explained based on FIG. Note that the same parts as those explained in FIGS. 1 and 2 are indicated by the same reference numerals, and the description thereof will be omitted (the same applies below). In this embodiment, a plurality of rotor bodies 14 each consisting of a ring-shaped permanent magnet 12 and a pair of rotor yokes 13 each having a cross section arranged on both sides of the permanent magnet 12 are provided, and these rotor bodies 14 are rotated. It is laminated on the shaft 7.

Therefore, the strength of the magnetic field can be easily adjusted by changing the number of laminated rotor bodies 14.

Note that the end surfaces of the mounting portions 15 that face each other are in contact with each other.

Next, a third embodiment of the present invention will be described based on FIG. 4. In this embodiment, a plurality of rotors 14 are provided, these rotors 14 are stacked on the rotating shaft 7, and when these rotors 14 are stacked on the rotating shaft 7, the rotors 14 are arranged in a spiral shape along the rotation direction. It has been shifted to Therefore, even when the number of field poles is small, uneven rotation is prevented and generation of vibration and noise is reduced.

Effects of the Invention As described above, the permanent magnet that rotates with the operation of the electric motor is formed into a ring shape and is attached to the rotating shaft, thereby reducing the centrifugal force acting on the permanent magnet. The strength of the magnet in the centrifugal direction can be improved, and therefore, accidents such as permanent magnets falling off can be prevented even when the motor is operated at high speed.
In addition, by stacking any number of rotor bodies, it is possible to easily configure various electric motors with different performances as required, and by stacking one rotor body in a spiral, the number of field poles is small. It is possible to prevent uneven rotation and reduce the generation of vibration and noise even if the rotor yoke This has effects such as being able to downsize the electric motor.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing the first embodiment of the present invention, and FIG.
The figure is an exploded perspective view showing the rotor part, and FIG. 3 is a longitudinal sectional front view showing the rotor part in a second embodiment of the present invention.
FIG. 4 is a longitudinal sectional front view showing the rotor portion in the third embodiment of the present invention, FIG. 5 is a longitudinal sectional front view showing the conventional example, and FIG.
The figure is a perspective view showing a rotor portion in a conventional example. 7...Rotating shaft, 12...Permanent magnet, 13...Rotor yoke, 14...Rotor body, 17...Magnetic detection device amount Applicant Tokyo Electric Co., Ltd.

Claims (1)

[Scope of Claims] 1. A rotor body consisting of a ring-shaped permanent magnet and a pair of rotor yokes with an L-shaped cross section that surrounds the outer periphery of the permanent magnet and abuts both end surfaces of the permanent magnet, A rotor for an electric motor, characterized in that the rotor body is mounted on a rotating shaft. 2. The rotor for an electric motor according to claim 1, characterized in that a plurality of rotor bodies are provided, and the plurality of rotor bodies are stacked on a rotating shaft. 3. The rotor for an electric motor according to claim 2, wherein a plurality of rotor bodies are stacked spirally on the rotating shaft. 4. A rotor for an electric motor according to claim 1, 2 or 3, characterized in that a magnetic detection device is provided in the end face thrust direction of the rotor yoke.