JPH08251865A - Vibration-suppressing rotating machine - Google Patents

Abstract

PURPOSE: To get stable operation in a wide range of revolutional speed by suppressing the vibration of a rotating part, in a rotary system. CONSTITUTION: This rotating machine suppresses the vibration occurring in the rotary system by controlling the magnetic floating force given to a rotor, based on the detection signal obtained by sensors, being provided with a magnetic floating motor part (2a: rotor, 3a: stator, 4a: coil), which drives the rotor 2a around the specified rotary shaft while floating the rotor 2a by exerting magnetic work on the rotor 2a, and distance sensors 103X and 103Y which detect the displacement in vertical direction to the axial direction of the shaft 5 couled with the rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing rotary machine suitable for applications requiring high speed and stable rotary operation.

[0002]

2. Description of the Related Art In factories, etc., due to demand for productivity, etc.
It may be required to continuously generate a large rotational drive force at a constant rotational speed. In such a case, a configuration is generally adopted in which a roller having a large diameter is attached to the rotating shaft of the rotating machine and a driving force is supplied to the final driven object via the roller. FIG. 6 shows an example of the configuration when the rotating machine is applied to such an application. In the figure, 1 is a rotating machine, which has a rotor 2 and a stator 3 fixed so as to surround the rotor 2. Stator 3
A coil 4 is wound around to generate a magnetic field for rotating the rotor 2. A shaft 5 penetrates the rotor 3, and the shaft 5 is rotatably supported at two points on both sides of the rotor 2 via ball bearings B1 and B2. A roller 6 having a large diameter is attached to the shaft 5 for transmitting the driving force.

[0003]

When the large roller 6 is attached to the shaft 6 of the rotating machine 1 as described above,
Along with this, the shaft end load and the shaft end mass of the rotating machine 1 increase, which causes a problem that large vibrations are generated in the rotating system including the rollers 6 based on the unbalanced amount. Hereinafter, this problem will be described in detail.

First, in order to prevent the rotation system from vibrating, it is necessary that at least the structure of the rotation system itself does not include a factor that causes the vibration, and that there is no imbalance. However, it is difficult to make the individual components of the rotating system such as the rotor 2 of the rotating machine 1 completely in axial symmetry, and it is extremely difficult to construct the rotating system in which they are assembled in complete axial symmetry. Therefore, a slight deviation will inevitably occur between the center of gravity of the rotary system and the rotary shaft of the rotary system. When the rotating body whose center of gravity deviates from the rotation axis is rotationally driven as described above, vibration having a frequency corresponding to the rotation speed is generated in the rotating body. In addition to such deviation of the center of gravity, there are several factors that constitute the unbalance amount of the rotating system, and the exciting force due to the unbalance amount is generated in the rotating system, which causes vibration in the rotating system. Becomes

The amplitude of this vibration is influenced by the rotation speed N of the rotating machine as illustrated in FIG. That is, when the rotation speed of the rotating machine is equal to or lower than the primary natural frequency N1 of the rotating system, the influence of the vibration due to the unbalance amount received by the rotating system is small, and the rotor of the rotating machine has a slight influence. Only amplitude vibrations occur. Therefore, in the example of FIG. 6, a normal rotating operation can be obtained without applying excessive bending stress to the shaft 6. However, the rotation speed of the rotating machine is the first natural frequency N1.
In the vicinity, the rotating system is hypersensitive to the vibration force due to the unbalanced amount, and a large vibration is generated in the roller and the like. When such a large vibration is generated in the roller 6, a large stress acts on the shaft 5,
In the worst case, the shaft 5 bends and becomes extremely dangerous. In order to avoid the occurrence of large vibrations in the rotary system, the rated speed of the rotary machine is generally set lower than the primary natural frequency N1 of the rotary system.

However, in order to increase productivity,
It is necessary to set the rated speed to a high value, and the following measures must be taken for that purpose. Increase the natural frequency. The amplitude of vibration that occurs when the rotation speed matches the natural frequency is kept low.

Here, it is necessary to increase the diameter of the shaft 5 in order to increase the natural frequency. However, when the shaft 5 is made larger, the dn value of the ball bearings B1 and B2 supporting the shaft 5 becomes larger, so that the life of the ball bearing is shortened. Therefore, there is a limit to increasing the diameter of the shaft 5.

On the other hand, the amplitude of the vibration of the roller 6 at the natural frequency is determined by the unbalance amount and the damping coefficient of the rotating system. The unbalance amount can be reduced to improve the stability or the damping coefficient. There is a limit to what you can do,
It was difficult to suppress the vibration of the roller 6 at the natural frequency.

The present invention has been made in view of the above-mentioned circumstances. Even when the rotation speed and the natural frequency of the rotating system match, no large vibration occurs, the high speed, and
An object of the present invention is to provide a vibration suppressing rotary machine that can be operated in a safe state.

[0010]

SUMMARY OF THE INVENTION According to the present invention, a magnetic levitation motor unit for rotatably driving a rotating unit around a predetermined rotation axis while exerting a magnetic action on the rotating unit, and the rotating unit. A sensor for detecting a displacement in a direction crossing the rotation axis, and a control circuit for controlling a magnetic levitation force applied to the rotating portion to suppress vibration generated in the rotating portion based on a detection signal obtained from the sensor, The gist is a vibration suppressing rotary machine characterized by comprising:

[0011]

According to the above construction, when vibration occurs in the rotating portion, the vibration is detected by the sensor, and the magnetic levitation force applied to the rotating portion is controlled based on the detection signal of the sensor.
Vibration of the rotating part is suppressed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a vibration suppressing rotary machine according to an embodiment of the present invention. In the structure shown in FIG. 6 above, the shaft 5 is rotatably supported by the ball bearings at two points on both sides of the rotor.
The shaft 5 is supported only at the points. Further, in this embodiment, distance sensors 103X and 103Y for detecting the displacement of the shaft 5 in the X-axis direction (vertical direction to the paper surface) and the displacement in the Y direction (vertical direction to the paper surface) are attached at the positions shown in the figure. As the distance sensors 103X and 103Y, for example, an eddy current type sensor or an optical type sensor can be used.

Further, in this embodiment, a magnetic levitation motor unit 10a including a rotor 2a, a stator 3a and a coil 4a is adopted as a rotary drive source. The magnetically levitated motor section 10a is a generally known one that is rotationally driven while levitating the rotor 2a by a magnetic action. Regarding the principle of the magnetic levitation and the magnetic levitation motor, for example, Japanese Patent Application No. 2-284689 (invention name: "magnetic bearing") or the Institute of Electrical Engineers of Japan held from June 10 to 12, 1992 in Kanazawa. This is explained in detail in the Proceedings of Dynamics Lectures on Electromagnetic Force at the 4th Symposium, pp. 251 to 256 (Title: "Research on magnetic levitation rotary motors"). The controller 100 shown in FIG. 2 controls the rotation of the magnetic levitation motor unit 10a and the control of the magnetic levitation force. Also,
In this embodiment, the controller 100 controls the magnetic levitation force generated in the magnetic levitation motor unit 10a based on the detection signals obtained from the distance sensors 103X and 103Y, thereby suppressing the vibration of the rotating system.

Next, the configuration of the controller 100 will be described with reference to FIG. In FIG. 2, reference numeral 101 is a rotation control unit, and a rotor 2a is provided via a rotation detector (not shown).
While monitoring the rotation angle of, the control necessary for rotationally driving the rotor 2a is performed based on this monitoring result. That is, as shown in FIG. 3, the permanent magnets 11 to 14 are attached to the rotor 2a of the magnetic levitation motor unit 10a, and the rotating magnetic field and the permanent magnet 11 are generated by generating the rotating magnetic field by the coil 4a. The rotation driving force is applied to the rotor 2a by the interaction with the rotors 14 to 14. Note that FIG. 3 is a cross-sectional view taken along the line II ′ of FIG.
Here, in order to apply a desired rotational driving force to the rotor 2a, the strength of the rotating magnetic field is controlled and the rotor 2a is controlled.
It is necessary to control so that the rotation angle of a and the direction of the rotating magnetic field maintain a predetermined phase state. The rotation control unit 101 calculates a current command value I1 to generate a necessary rotating magnetic field by the coil 4a based on the result of monitoring the rotation angle of the rotor 2a, and supplies this current command value I1 to the adder 104.

A levitation and vibration suppression control unit 102 performs control for magnetically levitating the rotor 2a and control for suppressing vibration generated in a rotating system including the rotor 2a. Specifically, it is as follows.

First, FIGS. 4A to 4D show how the rotor 2a rotates at a constant angular velocity ω. here,
When a rotating magnetic field is generated so as to maintain a constant phase relationship with the rotation angle of the rotor 2a, a magnetic levitation force in a constant direction can be constantly applied to the rotor 2a. In the illustrated example, the rotating magnetic field of 6 poles is generated by the coil 4a with respect to the rotor 2a of 4 poles, and the magnetic levitation force (arrow F) is always upward.
The following shows an example in which Further, by changing the phase difference φ between the rotation angle of the rotor 2a and the direction of the rotating magnetic field, the direction of the magnetic levitation force can be changed over 360 degrees as shown in FIG.

On the other hand, the distance sensors 103X and 103Y
Respectively output detection signals representing the distance in the X direction and the distance in the Y direction to the shaft 5. The levitation and vibration suppression control unit 102 uses the PID for these detection signals.
Predetermined processing including control is performed to find each magnetic levitation force in the X and Y directions to be applied to the rotor 2a. Here, each magnetic levitation force has a proportional element (P) and an integral element (I).
And the differential element (D) are included, the proportional element (P) among them is 0 when the shaft 5 is not vibrating and is in the ideal position, and the shaft 5 is in the X direction from the ideal position. When it is displaced in the (Y direction), it has a negative value according to the displacement amount, and conversely, when it is displaced in the -X direction (-Y direction), it has a positive value according to the displacement amount. The proportional element (P) and the integral element (I) exert the function of maintaining the rotor 2a and the shaft 5 at fixed positions. Further, the differential element (D) has a function of increasing the damping coefficient of the vibration of the rotary system.

The levitation and vibration suppression control unit 102 synthesizes the magnetic levitation forces in the X and Y directions thus obtained to localize the rotor 2a at a predetermined position and to vibrate the rotation system including the rotor 2a. The magnetic levitation force required to suppress the magnetic field is calculated, and the current command value I2 of the exciting current that must be applied to the coil 4a to obtain the rotating magnetic field required for the magnetic levitation force is calculated.

The adder 104 localizes the rotor 2a at a predetermined position and the current command value I1 for rotationally driving the rotor 2a obtained as described above, and suppresses vibration generated in the rotary system. And the current command value I1 required for are added. Then, the current command value I obtained by this addition is supplied to the excitation control unit 105. The excitation control unit 105 performs control for supplying an exciting current corresponding to the current command value I to the coil 4a.

According to the configuration described above, the rotating magnetic field generated by the coil 4a causes the rotor 2a to rotate and the shaft 5 to rotate. Here, when the rotation speed of the rotating machine 1a is lower than the primary natural frequency, large vibration does not occur in the shaft 5, and the shaft 5 is at the ideal position, the levitation and vibration suppression control unit 102 The magnetic levitation force for locating the rotor 2a at a predetermined position is obtained, and the current command value I2 necessary for generating this magnetic levitation force is added to the adder 104.
Supply to As a result of such control, the shaft 5 always maintains the ideal position.

On the other hand, when the rotation speed of the rotating machine 1a is near the natural frequency of the rotating system, a large vibration is likely to occur in the shaft 5 in the direction transverse to the axial direction. When such vibration occurs, the vibration is detected by the levitation and vibration suppression control unit 102 via the distance sensors 103X and 103Y. The levitation and vibration suppression control unit 102 generates a magnetic levitation force including a component necessary for suppressing the vibration of the rotating system including the rotor 2a in addition to the component for localizing the rotor 2a at a predetermined position. Then, the current command value I2 of the exciting current that must be supplied to the coil 4a to obtain the required rotating magnetic field is sent to the adder 104. As a result, vibration of the rotary system is suppressed.

Since such control is performed, the rotating machine 1
The vibration can be effectively suppressed even in a situation where the rotation frequency of a matches the natural frequency and large vibration is likely to occur on the shaft 5, and the operation of the rotating machine can be made stable with less vibration. .

The preferred embodiment of the present invention has been described above, but the scope of application of the present invention is not limited to this. For example, various types of magnetic levitation motors are known, but which type of motor is to be used depends on the application of the vibration suppressing rotary machine according to the present invention. Good. Also, the distance sensor 1
As for 03X and 103Y, appropriate ones may be selected in consideration of cost and required response performance. Also, the mounting position of the distance sensor should match the target rotary system,
It suffices to select a position where the vibration can be detected most quickly and accurately. For example, in FIG. 1, the vibration of the shaft 5 may be detected at a position near the roller 6.

[0024]

As described above, according to the present invention,
A magnetic levitation motor unit that rotates around a rotation axis while levitating the rotation unit by exerting a magnetic action on the rotation unit, and a sensor that detects a displacement of the rotation unit in a direction crossing the rotation axis, Since the rotating machine is configured by the control circuit that controls the magnetic levitation force applied to the rotating portion and suppresses the vibration generated in the rotating portion based on the detection signal obtained from the sensor, the rotation speed and the rotation system are unique. Even if the frequency matches, no big vibration occurs, high speed,
In addition, the effect that the rotating machine can be operated in a safe state is obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a vibration suppressing rotary machine according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a controller according to the embodiment.

FIG. 3 is a view showing a rotor and a stator in the same embodiment.

FIG. 4 is a diagram showing an operation of the magnetic levitation motor unit in the embodiment.

FIG. 5 is a diagram showing an operation of the magnetic levitation motor unit in the embodiment.

FIG. 6 is a cross-sectional view showing a configuration example of a general rotating machine.

FIG. 7 is a diagram showing the relationship between the rotation speed of the rotating machine and the vibration generated in the rotating system.

[Explanation of symbols]

 1a ... Vibration suppression rotary machine 2a ... Rotor 3a ... Stator 4a ... Coil 10a ... Magnetic levitation motor section 5 ... Shaft 103X, 103Y ... Distance sensor 6 ... Roller 100 ... Controller

Claims (1)

[Claims] 1. A magnetic levitation motor unit for rotatably driving a rotating unit around a predetermined rotation axis while exerting a magnetic action on the rotating unit, and a magnetic levitation motor unit for rotating the rotating unit in a direction transverse to the rotation axis. A vibration comprising: a sensor that detects a displacement; and a controller that controls a magnetic levitation force applied to the rotating portion and suppresses a vibration generated in the rotating portion based on a detection signal obtained from the sensor. Suppressing rotating machine.