JPS648206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bearing used in high-speed rotating machines, etc., and includes a light source and a photocell or phototransistor in order to detect the position of a supported body.
The present invention relates to a method of configuring a device that controls power supplied to an excitation coil of a magnetic bearing based on a signal from this detector.

FIG. 1 is a block diagram of a general rotating machine using magnetic bearings. In the figure, 15 is a rotating shaft which is a supported body, 16 is an armature disk attached to the rotating shaft, and 1 is an eddy current sensor, a capacitance sensor, etc. for detecting the axial position of the rotating shaft 15. 10 is a control circuit that processes the electric signal of the sensor 1; 11 is a power amplifier that supplies power to the electromagnets 12 and 13 according to the control signal of the control circuit 10; 17 is the position detector 1 and the electromagnet 12; 13
It is a frame that fixes the As shown in FIG. 1, the thrust magnetic bearing detects the axial position of a supported body composed of a rotating shaft 15 and an armature disk 16 as an electric signal by a position detector 1, and detects the position according to the signal. A control signal is generated by a control circuit 10, and in accordance with the control signal, a power amplifier 11 switches and supplies power to the electromagnet 12 or 13 so as to balance the thrust load of the supported object, thereby moving the supported object in the axial direction. to support it in a certain position.

According to the configuration shown in FIG. 1, at least two displacement detectors 1 are required in order to eliminate the influence on the inclination of the rotating shaft 15, and the structure of the magnetic bearing is complicated, resulting in problems in economy, manufacturability, and price. A problem arises.

This invention eliminates the above drawbacks. FIG. 2 shows an embodiment of the present invention. In Fig. 2, 2 is a power source for lighting the light source 3;
5 is a slit provided in the frame 17 to guide the light beam from the light source 3; 5 is a reflector plate for reflecting the light beam;
7 and 8 are photocells or phototransistors located at 180 degrees from each other; 9 receives the outputs of 7 and 8, cancels the influence on the inclination of the rotating shaft 15, and generates only a pure displacement component in the axial direction. 10 is a control circuit for processing the electric signal of the displacement signal processing circuit 9, and 11 is a power amplifier for switching and driving the electromagnet 12 or 13 in accordance with the signal from the control circuit. Also, 1
4 is attached to the tip of the rotating shaft 15, and a reflecting plate 5
This is a light amount blocking plate for increasing or decreasing the amount of light rays 4 reflected in directions 180 degrees from each other.

According to FIG. 2, the light rays generated by the light source 3 enter through the slits 6 provided at two locations on the upper part of the frame 17, and are converted into light rays 4 at a direction of 180° from each other by the reflection plate 5. Since the light intensity blocking plate 14 is attached to the rotating shaft 15, it has the role of increasing or decreasing the amount of light rays 4 reflected by the reflecting plate 15 in directions of 180° relative to each other in accordance with the axial displacement of the rotating shaft 15. There is. Since the electrical output signals of the photocells or phototransistors 7 and 8 change as the amount of light increases or decreases, the axial displacement of the rotating shaft 15 can be detected with the configuration shown in the figure. In addition, a light receiving part 7 such as a photocell,
8 are arranged at 180 degrees from each other, and the signal from the light receiving section is processed by a displacement signal processing circuit 9, so that the displacement in the axial direction of the rotating shaft 15 is detected by the increase or decrease in the detected overall amount of received light. Therefore, if the rotating shaft 15 is only tilted, the increase or decrease in the amount of light received by each light receiving section is canceled out by the signal processing circuit 9, and is not detected as an increase or decrease in the amount of light received as a whole.

Therefore, when the rotating shaft 9 changes, the inclination of the rotating shaft is not detected as an axial displacement, but the axial displacement is extracted and detected, so it does not follow the top motion and is detected as an axial fluctuation. can be controlled to support the rotating shaft at a fixed position in the axial direction.

As described above, according to the present invention, by using an inexpensive light source and optical sensor, it is possible to configure a control device without complicating the structure of the magnetic bearing.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a general control configuration of a thrust magnetic bearing, and FIG. 2 is an explanatory diagram showing an embodiment of the present invention. In the figure, 1 is a position detector, 2 is a power source, 3 is a light source, 4 is a light beam, 5 is a reflector, 6 is a slit, 7 and 8 are photocells or phototransistors, 9 is a displacement signal processing circuit, and 10 is a The control circuit includes a power amplifier 11, electromagnets 12 and 13, a light shielding plate 14, a rotating shaft 15, an armature disk 16, and a frame 17. still,
Identical and corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A rotary shaft that is rotatably provided, a magnetic bearing having a magnetic coil that supports the rotary shaft, a light source installed toward one end of the rotary shaft, and a light source installed on the fixed side in the axial direction of the rotary shaft. a reflecting part for reflecting light from the provided light source; a light receiving part for receiving reflected light from the reflecting part; a processing circuit that processes signals from the light receiving section; and a light shielding section that is fixed to the rotating shaft and that is arranged between the reflecting section and the light receiving section to block part of the reflected light that enters the light receiving section. The processing circuit processes a change signal of the amount of light received by each light receiving section due to the displacement of the light shielding section, extracts the amount of change in position of the rotating shaft in the axial direction, and supplies the signal to the excitation coil of the magnetic bearing. A control device for a magnetic bearing, characterized in that it controls electric power.