CN113803371B - Method and protection circuit for preventing magnetic-hydraulic double suspension bearing from falling - Google Patents

Abstract

The invention discloses a method for preventing a magnetic-liquid double-suspension bearing from falling and a protection loop thereof, namely, a falling-prevention protection loop is connected in parallel in each supporting loop of a magnetic-liquid double-suspension bearing hydrostatic supporting system; each anti-falling protection loop is composed of an energy accumulator, a two-position electromagnetic directional valve and an adjustable throttle valve which are sequentially connected in series. When the electromagnetic suspension system fails, the electromagnetic system is firstly closed, the axis locus is detected by using the displacement sensor, and the falling time of the bearing rotor is predicted. When the falling time is larger than the stability time threshold of the active speed regulating system, the rotating speed of the asynchronous motor and the gear pump is regulated only by the frequency converter to increase the oil supply pressure and flow of the static pressure cavity, so that the rotor is suspended temporarily, and the host is closed for maintenance. When the falling time is less than the time threshold, the anti-falling protection loop is quickly started, oil is supplied to the bearing static pressure cavity, buffering time is provided for the active speed regulation link, and the buffering time is larger than the difference value between the falling time and the active speed regulation time threshold.

Description

Method and protection circuit for preventing magnetic-hydraulic double suspension bearing from falling

technical field

The invention relates to the field of protection devices, in particular to a method for preventing a magnetic-hydraulic double suspension bearing from falling and a protection circuit thereof.

Background technique

Magnetic-hydraulic double suspension bearing is a new type of suspension bearing mainly based on electromagnetic suspension and supplemented by hydrostatic support. It can additionally increase the hydrostatic pressure support force without affecting the electromagnetic suspension force and effectively improve the running stability of the bearing. and its service life. Magnetic-hydraulic double suspension bearings are suitable for occasions and working conditions with medium speed and heavy load, large bearing capacity and high running stability. However, when the electromagnetic suspension system fails, due to the slow response speed of the hydrostatic support system, it is easy to cause the rotor in the magnetic-hydraulic double suspension bearing to fall, causing harm.

SUMMARY OF THE INVENTION

In order to solve the above problems in the prior art, the purpose of the present invention is to provide a protection circuit for preventing the fall of the magnetic-hydraulic double suspension bearing when the electromagnetic suspension system fails.

Another object of the present invention is to provide a protection method for preventing the fall of the magnetic-hydraulic double suspension bearing when the electromagnetic suspension system fails.

In order to achieve the above object, the present invention adopts the following technical solutions: a method for preventing the fall of the magnetic-hydraulic double suspension bearing, which comprises the following steps:

S1. Start the system and check whether the pressure of the accumulator meets the standard through the pressure gauge. If it does not meet the standard, start the asynchronous motor in the oil storage circuit of the accumulator to supply oil to the accumulator through the gear pump until its pressure reaches the standard, and the accumulator stores The oil circuit stops working;

S2. Check whether the current of the electromagnetic circuit of the electromagnetic suspension system is normal, and judge whether the electromagnetic system is invalid?

S3. When the electromagnetic suspension system fails, close the electromagnetic system, detect the axis trajectory of the magnetic-hydraulic double suspension bearing through the displacement sensor, and predict the drop time t of the bearing rotor through the working condition machine according to the displacement signal;

S4. When the drop time t is greater than the active speed regulation time threshold td of the magnetic-hydraulic double suspension bearing, the speed of the asynchronous motor and gear pump in the static pressure support system is only adjusted by the frequency converter of the active speed regulation link, and the static pressure of the bearing is increased. The oil supply pressure P and flow Q of the pressure chamber, the rotor is suspended for a short time, and the main engine is closed for maintenance;

When the drop time t is less than the active speed regulation time threshold td, the anti-drop protection circuit is activated, and the accumulator group in the anti-drop protection circuit quickly supplies oil to the bearing static pressure chamber, providing a buffer time tb for the active speed regulation link oil supply , the buffer time tb is greater than the difference between the drop time t and the active speed regulation time threshold td.

Preferably, the active speed regulation time threshold td is determined by simulating the drop of the rotor for many times.

A magnetic-hydraulic double-suspension bearing anti-drop protection circuit for a method for preventing the fall of the magnetic-hydraulic double-suspension bearing. In each support circuit of the magnetic-hydraulic double-suspension bearing hydrostatic support system, an anti-drop protection circuit is connected in parallel; the Each anti-drop protection circuit includes an accumulator, an electromagnetic reversing valve and an adjustable throttle valve in series; the accumulator is connected with a gear pump, an asynchronous electric circuit, a check valve, a pressure gauge and a fuel tank in sequence to form an accumulator. Energy accumulator circuit.

Compared with the prior art, the present invention has the following beneficial effects:

Because the present invention is connected in parallel with an anti-drop protection circuit in each working circuit of the magnetic-hydraulic double suspension bearing static pressure support system, when the electromagnetic suspension system fails, the electromagnetic system is immediately shut down, the anti-drop protection circuit is activated, and the anti-drop protection circuit is activated. The lubricating oil in the accumulator quickly supplies the static pressure chamber of the magnetic-hydraulic double suspension bearing, which makes up for the shortcoming of the slow response speed of the static pressure support system. Therefore, the present invention can effectively avoid a series of hazards caused by the falling of the bearing rotor and improve the bearing performance. service life.

Description of drawings

Figure 1 is a schematic diagram of the force of a single-degree-of-freedom magnetic-hydraulic double suspension bearing;

Fig. 2 is the anti-drop protection circuit diagram of the magnetic-hydraulic double suspension bearing when the electromagnetic suspension system of the present invention fails;

FIG. 3 is a flow chart showing the fall prevention of the magnetic-hydraulic double suspension bearing when the electromagnetic suspension support system of the present invention fails.

Main reference signs:

1. Filter, 2. Relief valve, 3. Gear pump, 4. Asynchronous motor, 5. Liquid temperature gauge, 6. Liquid level gauge, 7. Check valve, 8. Flow meter, 9. Filter, 10. Displacement sensor, 11, Magnetic-hydraulic double suspension bearing, 12, Throttle valve, 13, Electromagnetic reversing valve, 14, Pressure gauge, 15, Accumulator, 16, Globe valve; 17, Lower support unit, 18, The lower support cavity, 19, the upper support cavity, 20, the upper support unit.

Detailed ways

The structure and features of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that various modifications can be made to the embodiments disclosed herein, therefore, the embodiments disclosed in the specification should not be regarded as limitations of the present invention, but only as examples of the embodiments, the purpose of which is to make the present invention The features of the invention are obvious.

Magnetic-hydraulic double suspension bearing is a new type of suspension bearing mainly based on electromagnetic suspension and supplemented by hydrostatic support. The magnetic-hydraulic double suspension bearing includes two radial bearings and one axial bearing; the stator of the radial bearing is provided with four radial magnetic poles, each magnetic pole is provided with an oil inlet through hole, and each two magnetic poles constitute a magnetic pole. There are two permanent magnets in the axial bearing, and two oil inlet holes are arranged opposite to each other on the stator.

As shown in Figure 2, each support circuit of the hydrostatic support system of the magnetic-hydraulic double suspension bearing includes a gear pump 3, an asynchronous motor 4, a one-way valve 7, a pressure gauge 14 and a micro flowmeter 8 connected in sequence; The first end of the circuit is connected with the oil tank through the oil circuit, and the second end is connected with the bearing oil inlet chamber. The oil return chamber, filter 9, cooler and oil tank of the magnetic-hydraulic double suspension bearing 11 are connected in sequence to form an oil return circuit of the hydrostatic support system. The gear pump 3 in each support circuit is coaxially connected to the asynchronous motor 4, and the rotational speed of the asynchronous motor 4 is regulated by the frequency converter, thereby controlling the pressure of the upper, lower, left and right chambers of the bearing to realize the control of the rotor.

When the electromagnetic suspension system fails, due to the slow response speed of the magnetic-hydraulic double-suspension hydrostatic support system, it is easy to cause the rotor in the magnetic-hydraulic double-suspension bearing to fall. Therefore, as shown in FIG. In the support circuit, an anti-drop protection circuit is connected in parallel;

The accumulator 15 is connected with the gear pump 3 , the asynchronous motor 4 , the one-way valve 7 , the pressure gauge 14 and the oil tank in turn to form an oil storage circuit of the accumulator 15 .

A liquid thermometer 5 for measuring oil temperature and a liquid level gauge 6 for measuring oil level, as well as a filter 1 and an overflow valve 2 are also connected to the oil supply return of the magnetic-hydraulic double suspension hydrostatic support system.

A shut-off valve 16 is also connected to the pipeline connecting the accumulator 15 with the fuel tank.

The invention provides an anti-drop protection method for a magnetic-hydraulic double suspension bearing when an electromagnetic suspension system fails, as follows:

As shown in Figure 3, before the system is started, first, multiple tests are performed to simulate the rotor falling process, and the time range value t1-t2 of the rotor falling is measured, and then the anti-drop protection circuit is activated to measure the flow range q1-q2 required for anti-drop. , according to the flow q2 combined with the pressure-flow calculation formula to calculate the working pressure p of the anti-drop protection circuit. The maximum working pressure of the accumulator 15 in the anti-drop protection circuit is greater than or equal to the working pressure p of the anti-drop protection circuit.

Secondly, check the anti-drop protection circuit composed of the electromagnetic reversing valve 13, the accumulator 15 and the throttle valve 12. Due to the failure of the electromagnetic suspension system, the oil supply to the static pressure support system (the oil supply amount is less than or equal to q2) needs to be In the time range t3-t4, the appropriate valve port size of the throttle valve 12 is adjusted according to the time range t3-t4.

Finally, it is detected that the active speed control link of the bearing composed of the frequency converter in the working machine, the asynchronous motor 4 in the static pressure support circuit, and the gear pump 3 has been adjusted to make the magnetic-hydraulic double suspension bearing rotor normally suspend the time range t5. -t6, set the active speed regulation time threshold td according to time t6.

When starting the magnetic-hydraulic double suspension bearing rotor support system, first judge whether the pressure of the accumulator 15 meets the standard through the display of the pressure gauge 14. The energy device 15 supplies oil to make its pressure reach the standard, and the oil storage circuit stops working.

Then the magnetic-hydraulic double suspension control module works, as shown in Figure 1, the static pressure support force F _liquid,1,0 of the bearing rotor in the upper support chamber 19, and the static pressure support force F _liquid,2,0 , of the lower support chamber 18, The electromagnetic force F of the upper support unit 20 _{, 1,0} , and the electromagnetic force of the lower support unit 17, F _{, 2,0} are normally suspended under the coupling support. When the magnetic-hydraulic double suspension bearing is working normally, the current of the electromagnetic circuit is detected in real time by the ammeter to judge whether the electromagnetic system is invalid.

When the electromagnetic suspension system fails, the electromagnetic system is turned off, the axial trajectory s of the magnetic-hydraulic double suspension bearing is detected by the displacement sensor 10, and the drop time t of the bearing rotor is predicted by the working condition machine according to the displacement signal. When the drop time t is greater than the active speed regulation time threshold td, only the frequency converter of the active speed regulation machine adjusts the speed of the asynchronous motor 4 and the gear pump 3, increases the oil supply pressure P and flow Q of the static pressure chamber, and makes the bearing The rotor is suspended for a short time, and the main engine is shut down for maintenance.

When the drop time t is less than the active speed regulation time threshold td, the electromagnetic reversing valve 13 in the anti-drop protection circuit responds quickly, the electromagnetic reversing valve 13 opens, and the accumulator group 15 quickly supplies oil to the bearing static pressure chamber, which is an active The oil supply in the speed regulation link provides a buffer time tb, and the buffer time tb is greater than the difference between the drop time t and the active speed regulation time threshold td.

The advantages of the present invention are: when the electromagnetic suspension system fails, the present invention effectively makes up for the shortcoming of the slow response speed of the hydrostatic support system through the anti-drop hydraulic protection circuit, can effectively avoid a series of hazards caused by the falling of the bearing rotor, and improve the bearing performance. service life.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited to this. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention. should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (3)

1. a method for preventing magnetic fluid double suspension bearing from falling, is characterized in that: it comprises the steps: S1. Start the system and check whether the pressure of the accumulator meets the standard through the pressure gauge. If it does not meet the standard, start the asynchronous motor in the oil storage circuit of the accumulator to supply oil to the accumulator through the gear pump until its pressure reaches the standard, and the accumulator stores The oil circuit stops working; S2. Detect whether the current of the electromagnetic circuit of the electromagnetic suspension system is normal, and determine whether the electromagnetic system is invalid; S3. When the electromagnetic suspension system fails, close the electromagnetic system, detect the axis trajectory of the magnetic-hydraulic double suspension bearing through the displacement sensor, and predict the drop time t of the bearing rotor through the working condition machine according to the displacement signal; S4. When the drop time t is greater than the active speed regulation time threshold td of the magnetic-hydraulic double suspension bearing, the speed of the asynchronous motor and gear pump in the static pressure support system is only adjusted by the frequency converter of the active speed regulation link, and the static pressure of the bearing is increased. The oil supply pressure P and flow Q of the pressure chamber, the rotor is suspended for a short time, and the main engine is shut down for maintenance; or When the drop time t is less than the active speed regulation time threshold td, the anti-drop protection circuit is activated, and the accumulator group in the anti-drop protection circuit quickly supplies oil to the bearing static pressure chamber, providing a buffer time tb for the active speed regulation link oil supply , the buffer time tb is greater than the difference between the drop time t and the active speed regulation time threshold td. 2 . The method for preventing the drop of the magnetic-hydraulic double suspension bearing according to claim 1 , wherein the active speed regulation time threshold td is determined by simulating the drop of the rotor for many times. 3 . 3. A magnetic-hydraulic double-suspension bearing anti-drop protection circuit according to the method for preventing the fall of the magnetic-hydraulic double-suspension bearing according to claim 1 or 2, is characterized in that: in each of the magnetic-hydraulic double-suspension bearing hydrostatic support systems In the support circuit, an anti-drop protection circuit is connected in parallel; each of the anti-drop protection circuits includes an accumulator, an electromagnetic reversing valve and an adjustable throttle valve in series; The accumulator is connected with a gear pump, an asynchronous motor, a check valve, a pressure gauge and an oil tank in turn to form an accumulator oil storage circuit.

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