JPH0314936Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a rotating electrical machine that is supported in a non-contact manner so as to be able to rotate at high speed by an attraction-controlled magnetic bearing.

[Conventional technology]

Like machine tool spindles and turbomolecular pumps,
In electric machines that require higher rotational speeds, non-contact supported air bearings and magnetic bearings have come to be used instead of rolling bearings and sliding bearings as a means of increasing speed.

In the case of magnetic bearings, attraction-controlled magnetic bearings that utilize magnetic attraction force are used to obtain high rigidity, but in order to support the rotating shaft, all degrees of freedom except rotation around the rotating shaft must be restrained. Must be, mainly 5
Axis-controlled magnetic bearings are used.

A cross-sectional side view of the conventional example is shown in FIG.

1 is a rotating shaft that drives a load, 2 is a frame forming a machine frame, 3 is a motor section that generates torque, 31 is a stator core (33 is a coil end of a winding wound around this stator core), and 32 is a rotor core. .

41 is a radial bearing part that forms a magnetic bearing disposed on the left side, which excites the winding (413 is the coil end) wound around the stator core of 411, and floats and rotates due to the electromagnetic force generated between the rotor cores 412. It freely supports the rotating shaft 1, and 51 is a displacement sensor that detects the positional displacement between the tip of the stator core and the rotor core 512 using a detection winding (513 is a coil end) wound around the stator core 511.

Similarly, 42 is a radial bearing part arranged on the right side, 421 is a stator core (423 is a coil end), 422 is a rotor core, 52 is a displacement sensor, 521 is a stator core (523 is a coil end),
22 is a rotor core.

61 to 66 are ring-shaped spacers made of a non-magnetic material such as aluminum or duralumin.

That is, the motor 3 is placed in the center, radial bearings 41 and 42 are placed on both sides of the motor 3, and displacement sensors 51 and 52 for the radial bearings are placed outside of the motor 3.

[Problem that the invention attempts to solve]

In such an arrangement, the motor section 3, the radial bearing sections 41, 42, and the displacement sensors 51, 52
The windings wound around the stator core are the coil ends 33, 413, 423, 513, 52.
3 protrudes from the stator core in one direction of the rotating shaft, which has the disadvantage of increasing the overall length.

This was a significant increase in overall length compared to conventional roller bearings.

As the overall length increases in this way, the rotating shaft 1 also inevitably becomes longer.

Therefore, the natural frequency of the rotating shaft is also significantly reduced. The reduction is approximately inversely proportional to the square of the length.

The reason why the magnetic bearings 41 and 42 are used is to provide non-contact support to reduce rotational friction and enable higher speeds; however, as the natural frequency of the rotating shaft 1 decreases, the critical speed decreases. Therefore, there was a problem that the effect of using the magnetic bearings 41 and 42 could not be sufficiently exhibited.

[Means for solving problems]

The present invention includes a motor section 3, a radial bearing section 41,
At least one of the windings wound on the stator side of 42 and the displacement sensors 51, 52 has a diameter different from the other, and is arranged close to each other in one direction of the rotation axis so that the coil ends overlap in the diametrical direction. do.

[Effect]

By doing this, the overall length can be shortened even if the space factor of the stator core winding is sacrificed, so the length of the rotating shaft 1 can be shortened, the natural frequency can be raised, and the critical speed can be increased. .

〔Example〕

A cross-sectional side view of one embodiment of the present invention is shown in FIG.

In all drawings, the same reference numerals represent the same or corresponding parts.

The windings wound around the stator cores 31, 511, 521 of the motor section 3 and displacement sensors 51, 52 have approximately the same inner diameter, but the coil ends 33,
The outer diameter of 513 and 523 is the radial bearing part 4.
It is smaller than the inner diameter of the coil ends 413, 423 of Nos. 1 and 42. These are arranged close to each other in the axis 1 direction so that the coil ends 413, 423 of the radial bearing parts 41, 42 overlap on the outside of the coil end 33 of the motor part 3, and the coil ends 413, 423 of the radial bearing parts 41, 42 overlap. The coil ends 513, 523 of the displacement sensors 51, 52 are overlapped on the other inside of the ends 413, 423.

By doing this, the overall length can be shortened by the amount of overlap between the coil ends.

Therefore, although the outer diameter of the frame becomes somewhat larger, the overall length and the length of the rotating shaft become shorter, making it possible to increase the natural frequency, that is, the critical speed.

The following means can be considered as other embodiments of the present invention.

In the previous embodiment, the coil ends 413 and 423 of the bearing are placed outside the coil end 33 of the motor 3.
The displacement sensor 51 is placed inside the other coil end 413, 423 of the bearing 41, 42.
Although 52 coil ends 513 and 523 are arranged, if the coil ends overlap each other in the diametrical direction,
The relationship between inside and outside is arbitrary.

[Effect of idea]

Thus, according to the present invention, the length of the rotating shaft of a magnetically levitated rotating electrical machine can be shortened, and the bending of the rotating shaft, which is approximately inversely proportional to the square of the length of the rotating shaft, can be reduced by 1.
The next natural frequency can be raised, that is, the critical speed can be raised, and high-speed rotation is possible, making many contributions to this field.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a conventional example. 1... Rotating shaft, 2... Frame, 3... Motor section, 41, 42... Radial bearing section, 51, 52
...Displacement sensor, 31,411,421,51
1,521...Stator core, 32,412,4
22,512,522...Rotor core, 33,4
13,423,513,523...Coil end, 61-66...Spacer.

Claims (1)

[Scope of Claim for Utility Model Registration] In a rotating electric machine that is non-contact supported by a suction control type radial bearing, the coil ends of the windings wound around the stator core of the motor part, the radial bearing part, and the displacement sensor. The two stator cores are arranged in the axial direction so that the circumferential diameter is larger than the outer circumferential diameter of the coil end of the winding wound around any other stator core, and the coil ends of these two windings overlap in the diametrical direction. A magnetically levitated rotating electrical machine characterized by being arranged close to each other so as to overlap each other.