JP3042545B2 - Magnetic bearing device - Google Patents

Abstract

PURPOSE:To provide a magnetic bearing device which can perform high speed rotation continuously by preventing loss of balance of mass at the time of high speed rotation. CONSTITUTION:Laminated steel plate in which a plural number of steel plates are laminated is used as a rotor 4 in radial direction which is fitted and fixed on a rotary shaft 1. Inner peripheral edges of the plural number of steel plates are welded, and adhesive is impregnated between adjacent steel plates to integrate them in parts except the welded parts. Inside diameter is ground to the predetermined dimension to fit and fix on the rotary shaft 1. Consequently, even when the rotary shaft 1 rotates at high speed, the rotor 4 in radial direction is not deformed easily, balance of mass is not lost at the time of high speed rotation, and high speed rotation can be continued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A magnetic bearing device according to the present invention
Used to support rotating shafts of high-speed centrifuges.

[0002]

2. Description of the Related Art A high-speed rotating shaft such as a rotating shaft of a high-speed centrifugal separator is supported in a non-contact state by a magnetic bearing device as shown in FIG. ing.

The position (displacement) of the rotating shaft 1 rotating at high speed in the radial direction is determined by radial position detecting sensors 2 and 2 provided at both upper and lower ends of the rotating shaft 1, and the position in the thrust direction is determined by a thrust position detecting sensor. 3 makes each of them freely detectable. The radial position detection sensors 2 and 2 are provided at two positions at one position, and the mounting positions are shifted by 90 degrees in the circumferential direction.

[0004] As shown in FIG. 2, a plurality of silicon steel plates are laminated to form a radial rotor 4, 4 formed in a cylindrical shape.
Are externally fitted and fixed at a plurality of upper and lower locations (two locations in the illustrated example) on the outer peripheral surface of the rotary shaft 1.

The radial position detecting sensor 2 and the radial position detecting sensor 2 are provided on an inner peripheral surface of a housing 5 provided around the rotary shaft 1.
Radial electromagnets 6, the energization amount of which is controlled based on signals from 2, are provided so as to face the outer peripheral surfaces of the radial rotors 4, 4. The radial electromagnets 6, 6 are provided in such a manner that the mounting positions thereof are shifted by 90 degrees in the circumferential direction by four for one radial rotor 4, and power is supplied to these four radial electromagnets 6, 6. By adjusting the amount, the position of the rotary shaft 1 in the radial direction is adjusted.

Further, a flange-like portion 7 is provided on the outer peripheral surface of the intermediate portion of the rotary shaft 1, and a thrust whose electric power is controlled based on a signal from the thrust position detection sensor 3 is provided on the inner peripheral surface of the housing 5. The directional electromagnets 9 and 9 are provided so as to face the upper and lower surfaces of the flange portion 7.

The operation of the magnetic bearing device configured as described above is as follows.

Using the stator 13 fixed to the housing 5 and the rotor 14 fixed to the rotary shaft 1 as driving sources, the radial position of the rotary shaft 1 rotating at high speed is determined by radial position detection sensors 2, 2 provided at upper and lower ends. Detected by
It is sent to a controller (not shown). This controller compares the signal from each of the radial position detection sensors 2 and 2 with the signal indicating the reference position to determine the deviation, and in order to eliminate the deviation, the controller applies a signal to the plurality of radial electromagnets 6 and 6. The rotating shaft 1 is moved in the radial direction by controlling the amount of electricity.

Further, the thrust position of the rotating shaft 1 is detected by a thrust position detecting sensor 3 and sent to a controller (not shown), which is also compared with a signal indicating a reference position to obtain a deviation, and eliminates the deviation. To this end, the amount of electricity to the thrust direction electromagnets 9 is controlled to move the rotating shaft 1 in the thrust direction.

In FIG. 1, reference numeral 10 denotes a cooling water passage for cooling the electromagnets 6 and 9 and the stator 13 , and 11 and 11 denote end faces of the electromagnets 6 and 9 when the power supply to the electromagnets 6 and 9 is stopped. And a touch-down bearing for preventing the radial direction rotor 4 and the end face of the flange-shaped portion 7 from sliding each other.

[0011]

The magnetic bearing device constructed and operated as described above has the following problems to be solved conventionally.

That is, the radial rotors 4, 4 externally fitted and fixed to the outer peripheral surface of the rotating shaft 1 increase the attraction force acting between each radial electromagnet 6, 6 and each radial rotor 4, 4. Therefore, as shown in FIG. 2, a plurality of steel plates 12, 12 such as silicon steel plates each formed in a ring shape are overlapped, and an adhesive is vacuum-impregnated between the adjacent steel plates 12, 12. The steel plates 12 are bonded to each other. Then, it is press-fitted and fixed to the rotary shaft 1 in an interference fit state.

However, when a large centrifugal force is applied to each of the radial rotors 4 by rotating the rotating shaft 1 at a high speed, the inner diameter of the radial rotor 4 is increased based on the centrifugal force, and the stress of the press-fit fixing portion is increased. The state changes. On the other hand, it is inevitable that the adhesive bonding the adjacent steel plates 12, 12 will cause some elastic deformation when a large force is applied. For this reason, when the rotating shaft 1 rotates at high speed, the positional relationship between the steel plates 12, 12 may be shifted, and the shape of the entire radial direction rotor 4 may be distorted. When the shape of the radial rotor 4 is distorted in this way, the rotational balance of the rotating shaft 1 is displaced, causing vibration, and it becomes impossible to rotate the rotating shaft 1 at high speed.

The magnetic bearing device of the present invention eliminates the above-mentioned disadvantages.

[0015]

The magnetic bearing device according to the present invention comprises:
As in the conventional magnetic bearing device described above, for example, as shown in FIG. 1, a rotating shaft 1 rotating at a high speed, radial position detecting sensors 2 and 2 for detecting the position of the rotating shaft 1 in the radial direction, Radial rotors 4, 4 made of a material and fixed to the outer peripheral surface of the rotary shaft 1
And radial electromagnets 6, 6 which are provided to face the outer peripheral surfaces of the radial rotors 4, 4, and whose energization amount is controlled based on signals from the radial position detection sensors 2, 2. .

Further, in the magnetic bearing device of the present invention,
As shown in FIG. 2, the radial direction rotor 4 is a laminated steel plate type formed by laminating a plurality of steel plates 12. Then, the inner peripheral edges of the plurality of steel plates 12, 12 are welded to each other, and the portions except for the welded portions are integrated by impregnating the adhesive between the adjacent steel plates 12, 12. . Then, the inner diameter of the radial direction rotor 4 is ground to a predetermined size, and the radial direction rotor 4 is press-fitted and fixed to the outer peripheral surface of the rotating shaft 1.

That is, in a state where the steel plates 12, 12 are laminated as shown in FIG. 2, the inner peripheral portions of the respective steel plates 12, 12 are welded to a predetermined welding depth by argon welding, electron beam welding or the like. Then, an adhesive is vacuum impregnated into a gap existing between the adjacent steel plates 12 to form an integrated radial direction rotor 4. Thereafter, the inner circumferential surface of the radial direction rotor 4 is ground by an amount smaller than the welding depth, so that the inner diameter is slightly smaller than the outer diameter of the press-fitting fixed portion provided on the rotating shaft 1. Then, the radial rotor 4 is press-fitted into the press-fitting fixed portion, and is fixed to the press-fitting fixed portion in a tight fit state.

[0018]

The magnetic bearing device configured as described above controls the amount of current to the radial electromagnets 6, 6 and the thrust electromagnets 9, 9 to support the rotating shaft in a non-contact state. In itself, it is the same as the above-mentioned conventional magnetic bearing device.

Further, in the case of the magnetic bearing device of the present invention, since the inner peripheral edges of the steel plates 12, 12 constituting the radial rotor 4 are fixed to each other by welding, the bonding force between the adjacent steel plates 12, 12 is reduced. strong. As a result, when the rotating shaft 1 rotates at a high speed, the inner diameter of the radial rotor 4 increases, and even if the stress state of the press-fit fixing portion between the radial rotor 4 and the rotating shaft 1 changes, the plurality of steel plates 12 , 12 does not deform the radial rotor 4 and the mass balance of the rotating shaft 1 does not shift. Therefore, vibration does not occur with the rotation of the rotating shaft 1. In addition, the uniformity of the gap impregnated with the adhesive existing between the adjacent steel plates 12 does not collapse, and the magnetic characteristics around the radial rotor 4 do not change. Can be kept rotating at high speed.

Further, since the plurality of steel plates 12 are welded to each other only at the inner peripheral portion thereof, each radial electromagnet 6, 6 and each radial rotor 4, 4
The suction force acting between them does not weaken. Multiple steel plates 1
If 2, 2 are welded at the outer peripheral edge or even over the front surface, the magnetic flux flows by short-circuiting the outer peripheral surface portions of the radial rotors 4, 4, so that the attraction force is weakened.

[0021]

Since the magnetic bearing device of the present invention is constructed and operates as described above, it is possible to secure a sufficient attraction force between the radial electromagnet and the radial rotor while securing the attractive force.
It is possible to prevent the mass balance from being lost during high-speed rotation, so that high-speed rotation can be continued.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a magnetic bearing device to which the present invention is applied.

FIG. 2 is a perspective view of a radial rotor incorporated in the bearing device to which the present invention is applied.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Rotation axis 2 Radial position detection sensor 3 Thrust position detection sensor 4 Radial direction rotor 5 Housing 6 Radial direction electromagnet 7 Flange part 9 Thrust direction electromagnet 10 Cooling channel 11 Touchdown bearing 12 Steel plate 13 Stator 14 Rotor

Claims (1)

(57) [Claims] 1. A rotary shaft rotating at high speed, a radial position detecting sensor for detecting a position of the rotary shaft in a radial direction, and a cylindrical member made of a magnetic material, which is externally fitted and fixed to an outer peripheral surface of the rotary shaft. A magnetic bearing device comprising: a radial-direction rotor; and a radial-direction electromagnet provided to face an outer peripheral surface of the radial-direction rotor, and the amount of energization is controlled based on a signal from the radial position detection sensor. The radial direction rotor is a laminated steel plate type formed by laminating a plurality of steel plates, and the inner peripheral portions of the plurality of steel plates are welded to each other, and in a portion excluding a welded portion, adjacent steel plates are formed. The radial direction rotor is ground to a predetermined size by impregnating an adhesive between them, and the radial direction rotor is pressed into the outer peripheral surface of the rotating shaft. Magnetic bearing apparatus wherein a was boss.