JPS6040262B2 - small rotating electric machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to, for example, improving the joining gap of ring-shaped permanent magnets constituting a magnetic circuit, and by this improvement, a preferable magnetic waveform can be obtained.

In recent years, motors that directly drive rotating bodies have been widely used in high-end record players because they do not have a power intermediary mechanism such as a speed reducer, so they have advantages such as less uneven rotation, less vibration and noise, and longer durability. It's starting to happen.

The structure of this type of small rotary electric machine is such that an isometric ring-shaped ferrite magnet is fixed to the inner circumferential surface of the rotor/ring, and its lower end surface is magnetized with multiple poles to increase the rotational speed. Obtain a signal for detection.

However, in order to make this conventional type of rotating electric machine even less uneven in rotation and have a longer lifespan, there is a strong desire for a rotating electric machine with a higher starting torque. The starting torque of a rotating electric machine using conventional isotropic ferrite magnets is 0.
．． 5-lk9/skin, but in order to improve the "peeling" of the reproduced sound, a high torque 1.5-2k9/skin is required.In view of the above-mentioned situation, the inventors of the present invention We considered making the permanent magnet itself heterogeneous.

However, a single ring-shaped anisotropic magnet has manufacturing difficulties, and it is practical to incorporate multiple arc-shaped anisotropic permanent magnets and fix them inside the rotor housing as a ring-shaped permanent magnet. It is. However, there is a slight air gap between one magnet and an adjacent magnet.

If the lower end surface of this ring-shaped permanent magnet is magnetized with a large number of poles, one pole or less, even if the poles that hang over the air gap are magnetized, their characteristics will be lower than other locations, or they will be unnecessary. A pole is formed, making it impossible to obtain an accurate rotation speed detection signal. Therefore, there is a drawback that smooth rotation without unevenness cannot be obtained at low speed rotation. The purpose of this invention is to
It is an object of the present invention to provide an electric machine which eliminates the above-mentioned drawbacks, obtains accurate rotational speed detection signals through multi-pole monitoring, and performs smooth rotation. This invention relates to a rotor in which a plurality of arc-shaped permanent magnets are fixed as ring-shaped magnets for use in rotating electric machines such as players and servo motors for video disks, in which a coagulable permanent magnet is embedded in the joining gap of the permanent magnets. By using a magnet, a large number of magnetic poles are provided on the lower end surface of the ring-shaped magnet to detect the rotational speed, and the key point is to obtain smooth rotation without unevenness.

Next, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a partial vertical sectional view of the rotating electric machine of the embodiment, and the first
It is an AA sectional view in a figure. Reference numeral 1 denotes a rotor housing which is fixed to the pulp 6 via a shaft stop 5.

Reference numeral 2 denotes a ring-shaped permanent magnet, and in order to eliminate the gap between the plurality of arc-shaped permanent magnets fixed to the rotor housing 1 and an adjacent arc-shaped permanent magnet, another ring-shaped permanent magnet is installed to cover the gap 3. A flexible permanent magnet 13 is embedded in a joint gap between one arc-shaped permanent magnet and an adjacent arc-shaped permanent magnet.

The lower end surface 14 of the ring-shaped permanent magnet 2 is subjected to prescribed multi-pole magnetization. A rotor coil 7 is installed on the inner peripheral surface of the ring-shaped permanent magnet 2, and a multi-pole detection coil 8 is also installed. FIGS. 4 and 3 show a schematic diagram of a part of a conventional ring-shaped permanent magnet 2 made up of a plurality of circular arc-shaped permanent magnets, viewed from the outer side of the ring, and its multi-pole magnetization waveform. The magnetic force of the magnetic pole existing in the air gap 3 is significantly reduced compared to other magnetic poles. On the other hand, the 6th diagram shows a part of the ring-shaped permanent magnet according to the present invention viewed in the radially outward direction and its multi-pole magnetization waveform.
As shown in Fig. 5. It is shown that by using this invention, an accurate continuous magnetization waveform can be obtained. In this way, the magnetic poles of a large number of poles intersect with the magnetic poles of the same rotor, and the width of each magnetic pole is narrow, and the distance or degree of rotation to the next magnetic pole is also small, so the pulse width of the rotation speed detection signal is narrower,
Improves rotation speed detection accuracy and provides smooth rotation.

As explained above, by carrying out the present invention, it is possible not only to produce a specified number of magnetic poles, but also to produce a plurality of arcuate magnetic poles, including magnetization of a number of poles other than the specified number and magnetization according to an angle. Obtained regardless of magnet. Since the magnetization gap is minute, the detection accuracy of the rotational speed is increased, and a highly accurate servo signal can be provided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is a diagram showing a permanent magnet section taken along the line A-A in FIG. 1, FIG. 3 is a diagram showing a conventional magnetization waveform, and FIG. 5 is a schematic diagram showing a conventional magnet gap, FIG. 5 is a diagram showing a landing waveform of the present invention, and FIG. 6 is a schematic diagram showing a magnet gap of the present invention. 1: Rotor/Using, 2: Permanent magnet, 3: Gap. Outside r figure O figure 2 figure O figure 3 figure O figure 4 figure O figure juice figure

Claims (1)

[Claims] 1. In a rotating electrical machine equipped with a rotor having a circular cross section on which a plurality of arc-shaped permanent magnets are fixed to the inner peripheral surface so that there are almost no gaps in the circumferential direction, A flexible permanent magnet is embedded in the joint gap to form a ring-shaped magnet, its inner peripheral surface is magnetized approximately in the radial direction, and its lower end surface is magnetized with multiple poles for rotation speed detection. A small rotating electric machine featuring: