JPH0341214A - Non-contact supporting method and device - Google Patents

Abstract

PURPOSE:To prevent vibration while a rotor is rotated excessively by providing on the internal circumference of a stator electromagnetic poles with exciting coils and displacement detectors opposed with each other through a clearance between the rotor and a stator, and controlling the phase of an output from the detectors to control the suction force of the electromagnetic poles. CONSTITUTION:Two displacement detectors 61 and 62 for detecting vertical and lateral displacements of a rotor 1 are fixed near the poles of electromagnetic poles 41 to 48 with their detecting directions crossed at right angle. When the rotor 1 is rotated at high speed and the whirling is produced, the vibration displacement of the rotor 1 is detected by these displacement detectors 61 and 62. A phase-modified signal is produced in a phase controller 72 by means of the displacement signals, transmitted to a distributor 73, and a current corresponding to the phase-modified signal is applied to exciting coils 51 to 58 through current amplifiers 74 and 75. A magnetic suction force acts between the electromagnetic poles 41 to 48 and the rotor 1, a magnetic suction force, 90 deg. ahead of the displacement of the rotor in phase, acts as a damping force to suppress the vibration displacement magnitude of the rotor 1, and the rotor can be rotated excessively without producing vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for supporting a high-speed rotating body in a non-contact manner.

[Prior Art] Conventionally, air bearings and magnetic bearings have been used as bearings that enable high-speed rotation of rotating machines.

Air bearings send air into the bearing gap and use the static pressure to levitate the rotating body and support it in a non-contact manner. Therefore, there is almost no so-called support damping effect, which dampens vibrations as a support part. This also applies to dynamic pressure type air bearings.

Furthermore, the magnetic bearing floats and supports the rotating body in a non-contact manner using magnetic attraction force. In this case, the displacement of the rotating body is detected and feedback control is performed to keep it constant, so that support damping can be improved by the configuration of the controller.

[Problems to be Solved by the Invention] However, in the case of air bearings, support damping does not work, so even if whirling occurs when the rotating body rotates at high speed,
Since it is not possible to suppress this, there is a problem in that if the rotation speed is increased beyond that, the vibration increases and the critical speed cannot be exceeded.

In addition, in the case of magnetic bearings, it is necessary to have both control for levitation and control for adding support damping.
In addition to complicating the overall structure, in order to increase support rigidity, supplying a bias current to each excitation coil to add bias magnetic flux had the disadvantage of generating heat due to eddy currents during high-speed rotation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a precision bearing having a structure in which an air bearing is combined with a magnetic damper, and which has a supporting damping effect during high-speed rotation.

[Means for Solving the Problems] The present invention includes a rotor made of a ferromagnetic material, a ring-shaped stator made of a ferromagnetic material facing the outer periphery of the rotor with a gap therebetween, and a ring-shaped stator made of a ferromagnetic material that faces the rotor. In a non-contact support method, the rotor is supported by fluid supplied through the fluid supply holes, the rotor being supported by an electromagnetic pole having an excitation coil on an inner circumference of the stator; and a displacement detector that detects the displacement of the rotor, which is opposed to the rotor through a gap, and controls the phase of the output of the displacement detector to control the attractive force of the electromagnetic poles in accordance with the signal. It is.

[Operation] When the rotor rotates at high speed and whirls around, the vibration displacement of the rotor is detected by the displacement detector.

In response to this displacement signal, the phase controller generates a phase adjustment signal,
This signal is applied to the distributor, and a current corresponding to the phase adjustment signal is applied to the excitation coil via a current amplifier, thereby exerting a magnetic attraction force between the electromagnetic poles and the rotor.

The magnetic attraction force, which is advanced by 900 degrees with respect to the phase of this rotor displacement, acts as a damping force as a magnetic damper, suppressing the vibration amplitude of the rotor.

[Example] The present invention will be described with reference to embodiments shown in the drawings.

Fig. 1 is a front sectional view showing an embodiment of the present invention, and Fig. 2 is a side sectional view, showing a rotor l made of a ferromagnetic material and a ring made of a ferromagnetic material facing the outer periphery of the rotor l with a gap in between. A frame 21 is provided on the outer periphery of the stator 2 and is provided with a fluid supply pipe 22 that communicates with a fluid supply device (not shown). Fluid supply holes 3 (31, 32, 33, 34, 35, 36, 37, 38
) is provided. In addition, four pairs of electromagnetic poles 4 (41, 42, 43, 4
4, 45, 46, 47, 48) are provided, and each electromagnetic pole 4 is provided with an excitation coil 5 (5L52.53.54.55).
．． 56, 57, 58) are wound. In addition, electromagnetic poles 41.42 and 45.4 generate vertical attractive force.
The excitation coils 51, 52, and 55, 56 of No. 6 are each connected in series as a pair, and the electromagnetic poles 41 and 45 are in the same direction.
The magnetic circuits 42 and 46 are constructed in the opposite direction. Similarly, in the left and right directions, the excitation coil 5
3.54 and 57.58 are each connected in series as a pair, and the magnetic circuit is configured such that electromagnetic poles 43 and 47 are in the same direction, and 44 and 48 are in the opposite direction. Air is supplied to the fluid supply hole 3 by an air source (not shown), and is discharged toward the surface of the rotor l to form an air bearing between the outer periphery of the rotor l and the magnetic pole surface of the electromagnetic pole 4. Two displacement detectors 6 (6L 62) are fixed to the stator 2 near the magnetic poles of the electromagnetic pole 4 to detect vertical and horizontal displacements of the rotor l with their detection directions orthogonal to each other. The displacement detector 61 outputs the detected value in the vertical direction, and the displacement detector 62 outputs the detected value in the horizontal direction.
Input k8 to the control devices 7y and 7x, respectively, and connect the electromagnetic pole 4.
It is designed to control the suction power. As shown in Figure *3, the vertical control device 7y amplifies the detected value KY with a sensor amplifier 71 and uses it as a displacement signal of the rotor 1.

The displacement signal Vy is input to the phase controller 72 and the phase adjustment signal Vy is inputted to the phase controller 72.
and gives a command to the distributor 73. Distributor 73
is designed to control the current of the excitation coils 51, 52, 55, 56 of the electromagnetic poles 41, 42, 45, 46, which generate vertical attractive forces, through two current amplifiers 74, 75. The left-right direction control device 7x is also configured similarly to the up-down direction control device 7y, and is configured to control the currents of the excitation coils 53, 54 and 57, 58.

In the above configuration, when the rotor 1 rotates at high speed and whirls around, the displacement detector 6 detects the vibrational displacement of the rotor 1 as follows.

Upon receiving this signal, the phase controller 72 gives a command to the distributor 73, and the excitation coil 51,
52.55.56 are supplied with current and the electromagnetic poles 41.42
．． A magnetic attraction force acts on 45, 46 and the rotor IM. The resultant force F of the magnetic attraction forces generated by these four electromagnetic poles acts on the rotor 1 as a force in the vertical direction, and becomes a damping force of the magnetic damper that suppresses the vibration amplitude of the rotor 1.

Note that the phase controller 72 is mainly composed of a one-time differentiator or a two-time differentiator, and the phase of the resultant force F of the magnetic attraction force with respect to the displacement with respect to the vibration frequency to be damped is set to 9 of the displacement.
Although the displacement speed signal V is output so as to lead by 0'', it is widely known from a mechanical standpoint that this resultant force F acts as a damper against rotor vibration.

Further, a bandpass filter may be connected in series to the phase controller 72, and the phase may be controlled only for a specific frequency, for example, the frequency of a critical speed.

Here, FIG. 4 shows a comparison of the relationship between the vibration amplitude and the rotational speed in the case of only an air bearing and the case of an air bearing using the magnetic damper of the present invention. In other words, when a magnetic damper is not used and only an air bearing is used, the amplitude is (a
), (b), and (c), but the rotation speed of (b) is the critical speed. Conventionally, air bearings alone could not increase the rotation speed past the critical speed, but according to the present invention, the vibration amplitude can be suppressed to a small level by the action of a magnetic damper, as shown by the solid line in Figure 4. The rotation speed can be increased to above the critical speed.

As mentioned above, four pairs of electromagnetic poles were provided in one radial bearing to form a magnetic damper, but since the vibration of a rotating body is almost never limited to vibration in the horizontal direction, it is not necessarily necessary to provide four pairs of electromagnetic poles. do not have. For example, as shown in FIG. 5, if there is at least one pair of electromagnetic poles that exert a vibration damping force in the vertical direction, the vibration of the rotor l can be suppressed. That is, a pair of electromagnetic poles 41 and 42 may be provided in a fan-shaped part of the ring-shaped stator 2 side by side in the circumferential direction, and the displacement detector 6 may be arranged between the electromagnetic poles 4I and 42.

Alternatively, a pair of electromagnetic poles 41 and 42 may be provided in a fan-shaped part of the ring-shaped stator 2 in parallel in the axial direction of the rotor 1. In this case, as shown in FIG. 6, permanent magnets 8 having the same polarity as the opposing electromagnetic poles are provided on the ring-shaped surface of the rotor l including the portions facing the pair of electromagnetic poles 41 and 42, for example. If the electromagnetic pole 41 is the north pole, the permanent magnet 8 whose outer periphery is magnetized to the north pole is opposed to the electromagnetic pole 41, and a repulsive force is applied between the electromagnetic pole and the permanent magnet to produce the effect of a magnetic damper. You can have it.

Further, as in the previous embodiment, the attractive force between the electromagnetic pole and the permanent magnet may be utilized.

[Effects of the Invention] As described above, according to the present invention, air bearings provide static non-contact support, and magnetic dampers damp rotor vibrations during whirling during high-speed rotation. Since whirling is suppressed, the rotor can exceed the critical speed without causing large vibrations, which has the effect of greatly increasing the upper limit of the rotational speed of the rotating body.

[Brief explanation of drawings]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a side sectional view, Fig. 3 is a block diagram of the control device, Fig. 4 is an explanatory diagram of the vibration state, and Fig. 5 is another embodiment. FIG. 6 is a front view showing another embodiment, and FIG. 6 is a side sectional view showing another embodiment. I... Rotor, 2... Stator, 3 (3L32.3
3.34.35.36.37.38)...Fluid supply hole, 4 (41, 42, 43, 44, 45, 46, 47, 4
8)... Electromagnetic pole, 5 (5L52.53.54.55.
56.57.58)... Excitation coil, 6 (61, 62
)...Displacement detector, 7...Control device, 71...Sensor amplifier, 72...Phase controller, 73...Distributor, 74.75...Current amplifier, 8... Permanent magnet diagram Figure 3 Figure 4 Rotation speed Figure 5 Figure 6

Claims (1)

[Claims] 1. A rotor made of a ferromagnetic material, a ring-shaped stator made of a ferromagnetic material facing the outer periphery of the rotor with an air gap, and a ring-shaped stator made of a ferromagnetic material provided on the stator radially toward the rotor. A non-contact support method in which the rotor is supported by the fluid supplied through the fluid supply hole, the electromagnetic pole having an excitation coil on the inner periphery of the stator, and an electromagnetic pole connected to the rotor through a gap. and a displacement detector for detecting the displacement of the rotor facing each other, the phase control is performed in response to the output of the displacement detector, and the attractive force of the electromagnetic pole is controlled in accordance with the signal. Non-contact support method. 2. A plurality of pairs of the electromagnetic poles are provided at equal intervals on the inner periphery of the stator, two of the displacement detectors are provided with detection directions perpendicular to each other, and phase control is performed in response to the output of the displacement detector, 2. The non-contact support method according to claim 1, wherein the attractive forces of said electromagnetic poles in orthogonal directions are controlled in accordance with the signals. 3. A pair of electromagnetic poles is provided in a fan-shaped part of the ring-shaped stator, the displacement detector is disposed between the pair of electromagnetic poles, and phase control is performed in response to the output of the displacement detector; 2. The non-contact support method according to claim 1, wherein the attractive force of said electromagnetic pole is controlled in accordance with the signal. 4. A rotor made of a ferromagnetic material, a ring-shaped stator made of a ferromagnetic material facing the outer periphery of the rotor with a gap in between, and fluid supply holes provided in the stator radially toward the rotor. In the non-contact support device for supporting the rotor with fluid supplied through the fluid supply hole, the electromagnetic pole is provided protrudingly surrounding the fluid supply hole and has an excitation coil wound therebetween; at least one displacement detector that detects the displacement of the rotor provided; a phase controller that receives the output of the displacement detector and performs phase control; and a control that controls the attraction force of the electromagnetic poles in accordance with the signal thereof. A non-contact support device comprising: 5. The non-contact support device according to claim 1, wherein the force exerted on the rotor by the electromagnetic pole advances by 90 degrees with respect to the displacement of the rotor. 6. The non-contact support device according to claim 4 or 5, wherein the phase controller comprises a bandpass filter of a specific frequency and a differentiator. 7. The non-contact device according to any one of claims 4 to 6, wherein a plurality of pairs of the electromagnetic poles are provided at equal intervals on the inner periphery of the stator, and two of the displacement detectors are provided with detection directions orthogonal to each other. Contact support device. 8. The non-contact support device according to claim 4 or 6, wherein a pair of electromagnetic poles is provided in a fan-shaped part of the ring-shaped stator, and the displacement detector is disposed between the pair of electromagnetic poles. 9. The non-contact support device according to claim 8, wherein a pair of electromagnetic poles are arranged in a circumferential direction on a fan-shaped part of the ring-shaped stator. 10. The non-contact support device according to claim 8, wherein a pair of electromagnetic poles are arranged in a fan-shaped part of the ring-shaped stator in the axial direction of the rotor. 11. A permanent magnet having the same polarity as that of the opposing electromagnetic poles is provided on a ring-shaped surface of the rotor including a portion facing each of the pair of electromagnetic poles arranged in the axial direction of the rotor. The non-contact support device described in .