JPH06261498A - Vibration suppressor for rotating machine - Google Patents

Abstract

PURPOSE:To allow stabilized rotational operation over a wider r.p.m. range by suppressing vibration of rotary shaft. CONSTITUTION:Shaft 3 of a rotating machine is supported by a secondary yoke 102 arranged oppositely with electromagnets 101, LYa, etc., and displacement of the secondary yoke in the direction traversing the shaft is detected by means of a sensor 103Y. Magnetic force generated from the electromagnets is then controlled based on a detection signal from the sensor thus suppressing vibration of the shaft through the secondary yoke.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing device suitable for a rotating machine which requires high speed and stable rotating operation.

[0002]

2. Description of the Related Art FIG. 5 shows a structure of a rotary machine 1 with an overhang roller which is applied to a textile machine or the like in a spinning process. In FIG. 5, a part on one side of an axis J of the rotary machine 1 is cut. The status is shown. As shown in the figure, the main body of the rotating machine 1 is fixed to the device 2 to be driven. Reference numeral 3 denotes a shaft which is a rotating shaft of the rotating machine 1, and penetrates the inside of the main body of the rotating machine 1. The circumference of the shaft 1 is surrounded by a rotor 6, and a stator 7 that generates a magnetic force for rotationally driving the rotor 6 is mounted inside the rotating machine body so as to surround the rotor 6. One end of the shaft 1 is supported by a bearing portion 41 at the end of the main body via a ball bearing B1, and a part of the way to the other end of the shaft 1 is supported by a bearing portion 42 by the ball bearing B.
Supported via 2. A roller 5 is attached to the end of the shaft 3 protruding from the bearing 42 to the outside of the rotating machine. The rotational driving force generated by the rotating machine 1 is transmitted to the device to be driven via the roller 5.

According to the rotating machine 1 having such a structure, a rotating force is applied to the rotor 6 by the magnetic force generated by the stator 7, and this rotating force is transmitted to the roller 5 via the shaft 3. Then, in the spinning process, the roller 5 which is rotationally driven in this manner applies a tension to the yarn or guides the yarn.

[0004]

By the way, recently, due to a demand for improvement in production efficiency, the roller of this type of rotating machine is becoming larger. However, when the size of the roller is increased,
Along with this, the shaft end load and the shaft end mass of the rotating machine increase, which causes a problem that a large vibration is generated in the rotating system including the rollers based on the unbalanced amount. Hereinafter, this problem will be described with reference to FIGS.

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 the structure does not have an unbalanced amount. However, it is difficult to make the individual components of the rotating system such as the rotor completely perfect in axial symmetry, and it is extremely difficult to construct a completely rotating symmetrical system in the assembled rotating system. A slight deviation will inevitably occur between the center of gravity of the system and the axis of rotation of the rotating 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 a 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

FIG. 6 exemplifies a characteristic of vibration generated in the rotating body due to the unbalance amount described above, and a curve A in the same figure shows a case where the rotating machine 1 shown in FIG. 5 is rotationally driven. The relationship between the rotation speed N and the amplitude of the vibration generated at the point a of the roller 5 is shown. Generally, a rotating system including rollers, shafts, etc. has a natural frequency. When the rotation speed of the rotating machine 1 is equal to or lower than the natural frequency, the influence of vibration caused by the unbalanced amount received by the rotating system is small, and the rotor 5 has a small amplitude vibration as shown in FIG. Only happens.
Therefore, it is possible to obtain a normal rotation operation without applying excessive bending stress to the shaft (see FIG. 7).

However, when the rotation speed of the rotating machine 1 becomes close to the natural frequency, the rotating system becomes hypersensitive to the vibration force due to the unbalanced amount, and a large vibration is generated in the rollers and the like. FIG. 6 shows that the amplitude at the point a of the roller 5 is maximized at the primary natural frequency N ₁ .
Although there are actually many high-order natural frequencies higher than the second order, the illustration of the natural frequencies higher than the second order is omitted in FIG. When such a large vibration is generated in the roller 5, a large stress is applied to the shaft 3, and in the worst case, the shaft 3 bends and becomes extremely dangerous (see FIG. 8). Note that FIG. 8 shows the bending state of the shaft 3 in an exaggerated manner than it actually is. In order to avoid the occurrence of large vibrations in the rotating system, the rated speed NMAX of the rotating machine is generally set to be lower than the primary natural frequency N ₁ .

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 primary natural frequency. The amplitude of vibration that occurs when the rotation speed matches the natural frequency is kept low. Here, in order to increase the primary natural frequency, it is necessary to increase the diameter of the shaft 3. However, if the shaft diameter is increased, d of the ball bearing that supports the shaft 3
The larger the n value, the shorter the life of the ball bearing. Therefore, there is a limit to increasing the diameter of the shaft. On the other hand, the amplitude of the roller vibration at the primary natural frequency N ₁ is determined by the unbalance amount and the damping coefficient of the rotating system. However, the unbalance amount can be reduced to improve stability or increase the damping coefficient. There is a limit to what you can do, 1
It was difficult to suppress the vibration of the roller at the next 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, a large vibration does not occur in the rotating machine,
An object of the present invention is to provide a vibration suppressing device that can operate a rotating machine at a high speed and in a safe state.

[0010]

A vibration suppressing device for a rotating machine according to the present invention comprises a yoke for axially supporting a rotating portion of the rotating machine,
An electromagnet arranged to face the yoke, a sensor for detecting the displacement of the yoke in a direction crossing the rotation axis, and a magnetic force generated by the electromagnet is controlled based on a detection signal obtained from the sensor. And a control circuit for suppressing the generated vibration.

[0011]

According to the above construction, the yoke vibrates with the vibration of the rotary shaft. Then, the displacement of the yoke due to this vibration is detected by the sensor, the current of the electromagnet is controlled based on the detection signal of the sensor, and the vibration of the rotating portion is suppressed via the yoke.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a partially cutaway sectional view showing the structure of a rotating machine including a vibration suppressing device 200 according to a first embodiment of the present invention. Further, FIG. 2 shows I- of the vibration suppressing device 200.
It is a sectional view taken along line I '. In FIG. 2, the components of the rotating machine 1 such as the rotor are not shown in order to avoid complication. The conventional rotary machine (FIG. 5) described above has a configuration in which both ends of the shaft 3 are supported by bearings via ball bearings. However, in the rotary machine 1 shown in FIG. 1, instead of the bearing portion 41 in FIG. Thus, the vibration suppressing device 200 is provided. The configuration of the vibration suppressing device according to this embodiment will be described below.

Reference numeral 102 denotes a secondary yoke having a cylindrical shape, and the shaft 3 penetrates the inside of the secondary yoke 102. A cylindrical portion of about half along the axial direction of the secondary yoke 102 supports the shaft 3 via a ball bearing B1, and the remaining cylindrical portion of the secondary yoke 102 is made of elastic material such as rubber or metal spring. It is fixed to the end of the main body of the rotating machine via the body 104.

The primary yoke 101 has an annular shape,
It is attached to the inner wall of the main body of the rotating machine so as to face the secondary yoke 102 and form a concentric circle. As shown in FIG. 2, the primary yoke 101 has eight magnetic poles projecting from the inner circumference toward the side where the secondary yoke is located. These magnetic poles have coils LYa, LYb, LXa, LXb, LYc,
LYd, LXc, and LXd are each wound. FIG. 1 shows the coil LYa among these eight coils.

The coils LYa and LYb are connected in series or in parallel, and by energizing them, the primary yoke 101 → the magnetic pole in the coil LYb → 2 as shown by the broken line and arrow in FIG. Next yoke 102 → Magnetic pole in coil LYa → Primary yoke 101
A magnetic flux passing through the magnetic path
2 is sucked in the Y direction. The same applies to the other sets of coils, that is, the coils LXa and LXb, the coils LYc and LYd, and the coils LXc and LXd, and the secondary coil is formed by the coils and the magnetic poles protruding from the primary yoke 101. York 1
An electromagnet is configured to attract 02 in the X direction, the -Y direction, and the -X direction. The primary yokes 101 and 2
Eddy current is generated in the secondary yoke 102, which is the secondary yoke 1.
02 may act as a disturbance, but when this effect cannot be overlooked, the primary yoke 101 and the secondary yoke 102 may be laminated to reduce the eddy current.

Distance sensors 103X and 103Y are arranged so as to face the secondary yoke 102,
These distance sensors output a detection signal according to the distance to the secondary yoke 103. Note that only the distance sensor 103Y is shown in FIG. Distance sensor 103
As X and 103Y, for example, an eddy current type or an optical type can be used.

Detection signals obtained from the distance sensors 103Y and 103X are supplied to the vibration suppression control circuit 100 shown in FIG. The damping control circuit 100, based on a detection signal from each distance sensor, generates a magnetic flux that suppresses the vibration of the secondary yoke 102 in the Y direction or the X direction, so that the coils LYa, LYb, LXa, LXb, LYc are generated. , LY
It controls the energization amount of d, LXc, and LXd.

FIG. 3 shows a part of the entire circuit of the vibration suppression control circuit 100 which is related to suppression of vibration of the secondary yoke 102 in the Y direction. In the figure, the detection signal obtained from the distance sensor 103Y is given to the controller 112Y via the sensor amplifier 111Y. Controller 112
Y is a PID for the output signal of the sensor amplifier 111Y.
Predetermined processing including control is performed and output to the adder 121Y and the subtractor 122Y. Here, the controller 112
The output signal of Y includes a proportional element (P), an integral element (I), and a derivative element (D). Among these, the proportional element (P) is the secondary yoke 10 because the shaft 3 does not vibrate.
When 2 is in the ideal position, it is 0, and when the secondary yoke 102 is displaced from the ideal position in the Y direction, it has a negative value corresponding to the displacement amount. Conversely, when it is displaced in the -Y direction, It becomes a positive value according to the amount of displacement. This proportional element (P)
And the integral element (I) functions as a control signal to keep the secondary yoke 102 in place. Also, the differential element (D)
Functions as a control signal for increasing the damping coefficient of the vibration of the rotating system. The adder 121Y has a predetermined constant current command value S
On the other hand, the output signal of the controller 112Y is added and output, and the subtractor 122Y subtracts the output current of the controller 112Y from the constant current command value S and outputs it. Adder 12
The output signals of 1Y and subtractor 122Y are input to power amplifiers 131Y and 132Y, respectively. The power amplifier 131Y drives the coils LYa and LYb, while the power amplifier 132Y drives the coils LYc and LYd.

The circuit configuration relating to vibration suppression in the Y direction has been described above. However, the distance sensor 10 has a configuration similar to this.
Coil LXa, LXb, LX based on 3X detection signal
A circuit for controlling the energization amount for c and LXd is provided in the vibration suppression control circuit 100.

The operation of this embodiment will be described below. The magnetic field generated by the stator 7 drives the rotor 6 to rotate, and the shaft 3 rotates. When the rotation speed of the rotating machine 1 is lower than the primary natural frequency, no large vibration is generated in the shaft 3, and the secondary yoke 102 is in the ideal position, the output signal of the controller 112Y becomes zero. Therefore, in this case, the current corresponding to the constant current command value S is supplied to each coil, and the secondary yoke has the Y direction, the X direction, and the −Y direction.
Are attracted by magnetic forces that are uniform in the four directions, the negative direction and the -X direction, to maintain the ideal position.

On the other hand, when the rotation speed of the rotating machine 1 is near the natural frequency of the rotating system, a large vibration is likely to occur in the shaft 3 in the direction transverse to the axial direction. When such vibration occurs, the vibration is transmitted to the secondary yoke 102 via the ball bearing B1. Here, if the secondary yoke 102 vibrates in the Y direction and the −Y direction, for example, the displacement of the secondary yoke 102 based on this vibration is detected by the controller 112Y via the distance sensor 103Y and the sense amplifier 111Y, and the controller 11
A signal corresponding to the amount of displacement is output from 2Y. Here, the proportional element (P) in the output signal of the controller 112Y has a negative value when the displacement direction of the secondary yoke 102 is in the Y direction, which reduces the currents of the coils LYa and LYb, and the coil LYc and Increase LYd current. Conversely, when the displacement direction of the secondary yoke 102 is the -Y direction, the proportional component (P) becomes positive, increasing the currents of the coils LYa and LYb and decreasing the currents of the coils LYc and LYd. By using the proportional component (P) in the output signal of the controller 112Y and the integral component (I) to control the energization amount of each coil, the shaft 3 is fixedly positioned in the Y direction via the secondary yoke 102. The control to maintain at. Further, the differential component (D) in the output signal of the controller 112Y contributes to the control of the energization amount of each coil in a state in which the phase is advanced from the proportional element (P), and the damping coefficient of the rotating system including the shaft 3 Fulfill the function of enhancing. The vibration of the secondary yoke 102 in the X direction is also suppressed by the same operation as in the Y direction based on the detection signal obtained from the distance sensor 103X.

As described above, according to the vibration suppressing device of the present embodiment, the vibration is effectively suppressed even in the situation where the rotation frequency of the rotating machine matches the natural frequency and the large vibration is likely to occur on the shaft 3. Therefore, the operation of the rotating machine can be made stable with less vibration. A curve B in FIG. 6 shows the relationship between the rotation speed N of the rotating machine 1 and the amplitude of the point a of the roller 5 when the vibration suppressing device is attached according to this embodiment. It can be seen that the vibration in the vicinity of the primary natural frequency is suppressed to an extremely low amplitude value as compared with the characteristic (curve A) of the conventional rotating machine 1 having no vibration suppressing device.

<Modification> The following modifications of the embodiment described above are conceivable. (1) In the above embodiment, one distance sensor is provided for each of the X and Y directions, but two distance sensors are provided for each direction, that is, in the case of the Y direction, the secondary yoke approaches the Y direction. And a sensor for detecting the approach in the -Y direction. Further, the outputs of the two sensors in each direction are differentially amplified and used for control for suppressing vibration. Compared with the above embodiment, the detection sensitivity for the displacement of the secondary yoke is doubled, and the common-mode noise signal generated in the sensor, the amplifier, etc. due to the temperature change can be removed, and the displacement measurement accuracy is improved. improves.

(2) In the above embodiment, a constant current is supplied to each coil according to a constant current command and the secondary yoke 10 is used.
In response to the change from the ideal position of 2, the current flowing through one electromagnet is increased from the constant current and the current flowing through the other electromagnet is decreased from the constant current. However, instead of supplying a constant current to each coil as described above, when the secondary yoke 102 is displaced, the current may be supplied to one of the electromagnets to restore the original position. That is, when the secondary yoke 102 is displaced in the Y direction and a negative output signal is obtained from the controller, the current corresponding to this signal is applied to the coils LYc and LYd.
When a positive output signal is obtained from the controller after displacement in the -Y direction, a current corresponding to this signal is supplied only to the coils LYa and LYb. Specifically, the adder 121Y and the subtractor 122Y
Instead of a limiter that passes only a positive signal and a limiter that passes only a negative signal,
Arranged in front of each Y, each limiter has a controller 11
A 2Y output signal may be given.

(3) The vibration suppression control circuit may be arranged outside the rotating machine main body and connected to each sensor and each coil inside the rotating machine main body by a cable. (4) The spring force of the elastic body may apply a preload to the ball bearing through the secondary yoke in the direction toward the shaft center. By doing so, the characteristics of the ball bearing can be stabilized.

<Second Embodiment> FIG. 4 shows the configuration of the second embodiment of the present invention. In this embodiment, the elastic body 104 is inserted in the gaps G, G, ... (See FIG. 2) between each magnetic pole of the primary yoke 101 and the secondary yoke 102, and the secondary yoke 102 is formed by the primary yoke 101. It is elastically supported. In this embodiment, the same effect as that of the first embodiment can be obtained.

[0027]

As described above, according to the present invention,
Based on a detection signal obtained from a sensor that detects a displacement of the yoke in a direction crossing the rotation axis, a yoke that axially supports the rotating portion of the rotating machine, an electromagnet that is arranged to face the yoke, and a direction that intersects the rotation axis, Since the control circuit for controlling the magnetic force generated by the electromagnet and suppressing the vibration of the yoke is provided, the vibration generated in the rotating part of the rotating machine can be suppressed, and the rotation frequency of the rotating machine is the natural frequency. Even in the vicinity, it is possible to obtain an effect that stable rotation operation can be performed in a wide range of rotation speeds without generating large vibration.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of a rotating machine to which a vibration suppressing device according to a first embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view taken along the line I-I ′ of FIG.

FIG. 3 is a block diagram showing a configuration of a vibration suppression control circuit 100 in the embodiment.

FIG. 4 is a partially cutaway sectional view of a rotating machine to which a vibration suppressing device according to a second embodiment of the present invention is applied.

FIG. 5 is a partially cutaway sectional view showing a configuration of a conventional rotating machine.

FIG. 6 is a diagram for explaining the relationship between the number of revolutions of the rotating machine and the vibration generated in the roller and the effect of the present invention.

FIG. 7 is a diagram illustrating the behavior of the rotating machine when the rotation speed does not match the natural frequency.

FIG. 8 is a diagram illustrating the behavior of the rotating machine when the rotation speed matches the natural frequency.

[Explanation of symbols]

1 ... Rotating machine, 3 ... Shaft, 101 ... Primary yoke, 102 ... Secondary yoke, 103X, 103Y ... Distance sensor, LYa, LYb, LXa, LXb, LYc,
LYd, LXc, LXd ... Coil, 200 ... Vibration suppressing device.

Claims (1)

[Claims] 1. A yoke that axially supports a rotating portion of a rotating machine, an electromagnet that is arranged to face the yoke, a sensor that detects displacement of the yoke in a direction crossing the rotating shaft, and a detection obtained from the sensor. A vibration suppressing device for a rotating machine, comprising: a control circuit that controls a magnetic force generated by the electromagnet based on a signal to suppress vibration generated in the yoke.