JP5428550B2 - How to obtain influence coefficient - Google Patents

Description

  The present invention relates to an influence coefficient acquisition method for acquiring an influence coefficient of a rotating body.

  The rotating body is provided in a rotating machine and rotates about its axis. In the present application, the rotating machine is a fluid machine in which rotating blades that exert force on a fluid are provided on a rotating body. The rotating machine includes a prime mover and a driven machine. The prime mover converts the energy of the fluid into rotational kinetic energy by rotationally driving the rotating body by the pressure that the fluid acts on the rotor blades. This rotational kinetic energy is the kinetic energy of the rotating body including the rotor blades. As a prime mover, for example, there is a gas turbine (axial turbine, radial turbine). The driven machine applies rotational kinetic energy to the fluid by rotating the rotor blades that are rotationally driven to apply pressure to the fluid. This rotational kinetic energy is the kinetic energy of the rotating body including the rotor blades. Examples of the driven machine include a compressor (an axial flow compressor, a mixed flow compressor, a cross flow compressor, and a pump provided in a centrifugal compressor, an aircraft engine, or the like). In addition, some rotating machines have a turbocharger that functions as both a prime mover and a driven machine.

  The influence coefficient indicates the vibration change of the rotating body with respect to the rotation balance change of the rotating body. The influence coefficient is used for correcting the balance of the rotating body. For this reason, the influence coefficient of the rotating body is acquired before the balance of the rotating body is corrected.

  Conventionally, the influence coefficient has been obtained using a test weight as follows. First, without using the trial weight, the rotating body is rotated, and the vibration of the supporting body that supports the rotating body is measured. Next, the trial weight is attached to the rotating body, the rotating body is rotated, and the vibration of the support that supports the rotating body is measured. Then, the influence coefficient is calculated from the vibration when the trial weight is not used, the vibration when the trial weight is attached, and the mass and attachment position of the trial weight. The vibration used for calculating the influence coefficient is preferably a vibration having the same frequency component as the rotation speed of the rotating body (that is, the number of rotations per second).

  Using the influence coefficient obtained in this way, the balance of the rotating body is corrected as follows. From the influence coefficient, unbalance data of the rotating body is calculated. At the correction position indicated by the unbalance data, the rotating body is cut by the mass indicated by the unbalance data. Thereby, the balance of the rotating body is corrected. Such a balance correction method is called an influence coefficient method, and is described, for example, in Patent Document 1 below.

JP 2008-102049 A

However, the influence coefficient acquisition method using the test weight has the following problems.
(1) Since the trial weight is attached and removed, it takes time.
(2) There are bonding and screwing methods for attaching the test weight, but in the case of bonding, the mass of the adhesive cannot be grasped, and in the case of screwing, the screw and test weight are scattered when the screw loosens during rotation. To do.

  Therefore, an object of the present invention is to provide an influence coefficient acquisition method for acquiring an influence coefficient with high accuracy without using a trial weight.

In order to achieve the above object, according to the present invention, an influence coefficient acquisition method for acquiring an influence coefficient indicating a vibration change of a rotating body with respect to a rotation balance change of the rotating body,
A first vibration data acquisition step of acquiring first vibration data by measuring vibration of a support that supports the rotation body in a state where the rotation body is rotating;
A cutting step for giving a rotational balance change to the rotating body by cutting a part of the rotating body;
A second vibration data acquisition step of acquiring second vibration data by measuring the vibration of the support while the rotating body is rotating;
A coefficient calculation step for calculating an influence coefficient of the rotating body based on the first vibration data, the rotation balance change given in the cutting step, and the second vibration data; An acquisition method is provided.

In the influence coefficient acquisition method of the present invention described above, the first vibration data is acquired by vibration measurement, the rotation balance change is then given to the rotating body by cutting, and then the second vibration data is acquired by vibration measurement. Thereafter, since the influence coefficient is calculated based on the first vibration data, the rotational balance change, and the second vibration data, the work of attaching and removing the trial weight for changing the balance is eliminated. Therefore, the time for acquiring the influence coefficient can be shortened.
Further, since the trial weight is not used, an accident in which the trial weight is scattered due to the rotation of the rotating body does not occur.
Further, the error in the mounting position and mass of the trial weight is eliminated. That is, since the rotation balance change can be accurately obtained from the cutting data, the calculation accuracy of the influence coefficient is improved.

According to a preferred embodiment of the present invention, a rotating machine different from the measuring object rotating machine having the rotating body, a reference rotating machine of the same model as the measuring object rotating machine is prepared,
Obtain the influence coefficient of the rotating body of the reference rotating machine as the reference influence coefficient,
Calculate the unbalanced data U1 from the reference influence coefficient,
In the cutting step, the rotating body is cut based on the unbalance data U1.

  Since the reference rotary machine and the measurement target rotary machine are the same model, cutting the rotary body of the measurement target rotary machine using the reference influence coefficient for the rotary body of the reference rotary machine means that the measurement target rotary machine is Will correct the balance. Therefore, the cutting of the cutting step can serve both as a step for obtaining the influence coefficient of the rotating body of the target rotating machine and a step for correcting the balance of the rotating body.

Further, according to a preferred embodiment of the present invention, an unbalance data calculation step of calculating unbalance data U0 from the influence coefficient calculated in the coefficient calculation step;
And a balance correction step of cutting the rotating body of the rotating machine to be measured based on the unbalance data U0.

The balance of the measurement target rotating machine can be corrected with high accuracy by cutting the rotating body of the measurement target rotating machine using the influence coefficient of the rotating body of the measurement target rotating machine calculated in the coefficient calculating step.
Moreover, since the balance of the rotating body of the rotating machine to be measured has already been corrected in the above-described cutting step, the balance accuracy of the rotating body is further increased in the balance correcting step. In addition, after the balance correction step, when the balance of the rotating body of the measurement target rotating machine is corrected by the influence coefficient method, the number of corrections can be reduced.

  According to the present invention described above, it is possible to acquire an influence coefficient with high accuracy without using a trial weight.

The influence coefficient acquisition apparatus which can be used for the influence coefficient acquisition method of this invention is shown. It is an II-II arrow line view of FIG. It is a waveform which shows vibration data. It is a complex plane representing vibration data. 5 is a flowchart illustrating an influence coefficient acquisition method according to an embodiment of the present invention. The case where the influence coefficient acquisition apparatus of this invention is provided to a supercharger is shown.

  An embodiment for carrying out the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

  FIG. 1 shows an influence coefficient acquisition apparatus 10 that can be used in the influence coefficient acquisition method of the present invention. 2 is a view taken in the direction of arrows II-II in FIG. The influence coefficient acquisition device 10 includes a support 3, an acceleration sensor 5, an angle sensor 7, a calculator 9, and a cutting device 11.

  The support 3 supports the rotating body 13 of the rotating machine. The rotating body 13 is rotatable about the axis C of the rotating body 13 while being supported by the support body 3. In addition, a part of the support body 3 may be comprised by the stationary side member of a rotary machine.

  The acceleration sensor 5 is attached to the support 3. The acceleration sensor 5 measures the acceleration (that is, vibration) of the support 3 while the rotating body 13 is rotating, and outputs a vibration signal indicating the acceleration to the calculator 9. As the acceleration sensor 5, a known sensor that can be used for acquiring the influence coefficient can be used.

  The angle sensor 7 detects the rotation angle of the rotating body 13 and outputs a rotation angle signal indicating the rotation angle to the calculator 9. The rotation angle changes from zero degrees to 360 degrees when the rotating body 13 rotates once. That is, the rotation angle indicates an angle at which the rotator 13 is rotated from the rotation phase (start point rotation angle) of the rotator as a predetermined start point.

The computing unit 9 extracts vibration data based on the vibration signal and the rotation angle signal, and calculates an influence coefficient from the vibration data. The vibration data is composed of vibration amplitude and phase θ. FIG. 3 shows the amplitude and phase θ of the vibration. In FIG. 3, the horizontal axis indicates the rotation angle of the rotating body 13 detected by the angle sensor 7, and the vertical axis indicates the intensity of the primary vibration among the vibrations detected by the acceleration sensor 5. The primary vibration is a vibration having the same frequency component as the rotational speed of the rotating body 13. That is, the primary vibration amplitude is a component having the same frequency [Hz] as the rotational speed (the number of rotations per second) of the rotating body 13 during vibration measurement by the acceleration sensor 5 from the vibration signal output from the acceleration sensor 5. It is the extracted vibration. In FIG. 3, the phase θ indicates the deviation of the primary vibration with respect to the reference rotation angle (zero degree in the example of FIG. 3). That is, the phase θ represents a deviation of the rotation angle that is the starting point of the period of the primary vibration with respect to the reference rotation angle.
Vibration data (that is, vibration data X1 and X2 described later) is represented by a complex number. FIG. 4 shows the vibration data expressed in complex numbers. As shown in FIG. 4, the vibration data is expressed as a complex number with the magnitude (absolute value) R of the primary vibration and the above-mentioned phase θ as the declination (hereinafter the same). The arithmetic unit 9 generates complex vibration data from the vibration signal from the acceleration sensor 5 and the rotation angle signal from the angle sensor 7.

  The cutting apparatus 11 includes a cutting tool 11a (for example, an end mill) that cuts the cutting target portion 13a of the rotating body 13, and a three-dimensional (for example, X axis direction and Y axis direction orthogonal to each other in FIG. 1). , A drive mechanism 11b that moves in the Z-axis direction), and a position control unit 11c that controls the position of the cutting tool 11a by controlling the operation of the drive mechanism 11b. The position controller 11c cuts the cutting target portion 13a according to the input cutting data. The cutting target portion 13a is, for example, a nut or a columnar member attached to the tip of the rotating shaft that constitutes the rotating body 13.

  FIG. 5 is a flowchart illustrating an influence coefficient acquisition method according to an embodiment of the present invention. This influence coefficient acquisition method includes a first vibration data acquisition step S1, a cutting step S2, a second vibration data acquisition step S3, a coefficient calculation step S4, an unbalance data calculation step S5, and a balance correction step S6.

In the first vibration data acquisition step S <b> 1, the acceleration sensor 5 of the support body 3 that supports the target rotating body 13 in a state where the rotating body 13 (hereinafter referred to as the target rotating body 13) of the measurement target rotating machine rotates. While the vibration (that is, acceleration) is measured, the angle sensor 7 detects the rotation angle, thereby acquiring the first vibration data X1. The first vibration data X1 is expressed by the following formula (1).

X1 = ar1 + jai1 (1)

Here, ar1 is a real part, ai1 is an imaginary part, and j is an imaginary unit (hereinafter the same).
The calculator 9 performs the acquisition of the first vibration data X1. That is, the calculator 9 generates first vibration data X1 based on the vibration signal from the acceleration sensor 5 and the rotation angle signal from the angle sensor 7 in the first vibration data acquisition step S1.

  In the cutting step S <b> 2, the cutting device 11 cuts a part of the cutting target portion 13 a of the target rotating body 13, thereby giving the target rotating body 13 a change in rotational balance.

In the second vibration data acquisition step S3, the angle sensor while the acceleration sensor 5 measures the vibration (that is, acceleration) of the support body 3 that supports the target rotating body 13 while the target rotating body 13 is rotating. The second vibration data X2 is acquired by 7 detecting the rotation angle. The second vibration data X2 is expressed by the following equation (2).

X2 = ar2 + jai2 (2)

Here, ar2 is a real part and ai2 is an imaginary part.
The calculator 9 acquires the second vibration data X2. That is, the calculator 9 calculates the second vibration data X2 based on the vibration signal from the acceleration sensor 5 and the rotation angle signal from the angle sensor 7 in the second vibration data acquisition step S3.

In the coefficient calculation step S4, the influence coefficient F0 of the target rotating body 13 is calculated based on the first vibration data X1, the rotation balance change given in the cutting step S2, and the second vibration data X2. The influence coefficient F0 is calculated by the following equation (3).

F0 = (X2-X1) / {− M (cos θ1 + jsin θ1)} (3)

Here, −M (cos θ1 + jsin θ1) represents the change in rotational balance given to the target rotating body 13 in the cutting step S2. Specifically, M is the converted mass cut in the cutting step S2. The cut equivalent mass M is M = r0 × m0. r0 is the radial distance from the axis C of the target rotating body 13 to the cutting position at the cutting step S2, and m0 is the mass cut at the cutting step S2. On the other hand, θ1 represents the rotational position of the cutting position. This rotational direction position may be expressed by a phase with respect to a predetermined rotational direction position.
Note that the calculator 9 executes the coefficient calculation step S4. That is, the arithmetic unit 9 calculates the influence coefficient F0 by the equation (3). The cutting data indicating the rotation balance change may be input from the position control unit 11c to the calculator 9. That is, the position control unit 11c may output the cutting data related to the cutting performed in the cutting step S2 to the computing unit 9, so that the computing unit 9 may convert the cutting data into the rotation balance change expressed in a complex number. . Instead, unbalance data U1, which will be described later, may be input to the calculator 9 as the rotation balance change.

In the unbalance data calculation step S5, the unbalance data U0 is calculated from the influence coefficient F0 calculated in the coefficient calculation step S4. The unbalanced data U0 is calculated by the calculator 9 according to the following equation (4).

U0 = X2 / F0 (4)

Here, X2 is the above-described second vibration data.

In the balance correction step S6, the cutting target portion 13a of the target rotating body 13 is cut based on the cutting position and the cutting amount indicated by the unbalance data U0. The unbalance data U0 is input from the calculator 9 to the position controller 11c. The position control unit 11c moves the cutting tool 11a by controlling the drive mechanism 11b based on U0, whereby the cutting target unit 13a is cut according to U0.
U0 is expressed by the following equation (5), where A is an absolute value and the deflection angle is θ2.

U0 = A (con θ2 + jsin θ2) (5)

A represents an unbalanced mass, and A = r1 × m1. Here, r1 is a radial distance from the axis C of the target rotating body 13 to the cutting position in step S6, and m1 is a mass to be cut in step S6. On the other hand, θ2 represents the rotational position of the cutting position. Accordingly, in step S6, the cutting tool 11a is moved in the direction of the axis C1 until the cutting mass reaches m1 while being positioned at the radial position and the rotational position indicated by r1 and θ2. At this time, the position control unit 11c calculates a distance for moving the cutting tool 11 in the direction of the axis C based on the density of the cutting target part 13a and, if necessary, the shape of the cutting target part 13a. The drive mechanism 11b is controlled based on the above.

Preferably, the above-described cutting step S2 is performed using a reference influence coefficient. The reference influence coefficient is an influence coefficient of the rotating body 13 (hereinafter referred to as the reference rotating body 13) of the reference rotating machine. The reference rotating machine is a rotating machine different from the measuring target rotating machine having the target rotating body 13, but is the same model as the measuring target rotating machine. The reference influence coefficient is obtained as follows.
It is preferable to acquire the reference influence coefficient by using the influence coefficient acquisition device 10 used to acquire the influence coefficient of the target rotating body 13. In this case, the reference influence coefficient of the reference rotator 13 is acquired by executing steps S1 to S4 in FIG. 5 by the same method as the acquisition method of the influence coefficient F0 of the target rotator 13. That is, first vibration data (corresponding to the above X1) is acquired for the reference rotator 13 as in step S1, and a part of the cutting target portion 13a of the reference rotator 13 is cut as in step S2. As in step S3, second vibration data (corresponding to X2 above) is acquired for the reference rotating body 13, and a reference influence coefficient (corresponding to F0 above) is calculated as in step S4. However, the reference influence coefficient may be acquired using a trial weight as in the above-described prior art, or may be acquired by other methods. Even in these cases, the reference rotator 13 is supported by the support 3 used for obtaining the influence coefficient F0.
Unbalance data U1 is calculated from the reference influence coefficient. U1 may be calculated using a formula similar to the calculation of U0. In this case, in the above-described cutting step S2, the cutting tool 11a is moved in the direction of the axis C1 until the cutting mass reaches the mass indicated by U1 while being positioned at the radial position and the rotational position indicated by U1.
Note that the reference influence coefficient does not coincide with the influence coefficient F0. This is because, even if the reference rotary machine and the measurement target rotary machine are the same model, there is a manufacturing error.

  In the influence coefficient acquisition method of the present invention described above, the following effects (A) to (D) are obtained.

(A) The first vibration data X1 is acquired by vibration measurement, then the rotational balance change U0 is given to the target rotating body 13 by cutting, then the second vibration data X2 is acquired by vibration measurement, and then Since the influence coefficient is calculated based on the first vibration data X1, the rotation balance change U0, and the second vibration data X2, the work of attaching and removing the test weight for changing the balance is eliminated. Therefore, the time for acquiring the influence coefficient can be shortened. Further, since the trial weight is not used, an accident in which the trial weight is scattered due to the rotation of the target rotating body 13 does not occur. Further, the error in the mounting position and mass of the trial weight is eliminated. That is, since the rotation balance change can be accurately obtained from the cutting data, the calculation accuracy of the influence coefficient is improved.

(B) The cutting step S2 is performed using the reference influence coefficient of the reference rotating machine of the same model, which has an error with the influence coefficient F0, and then step S2 so as to correct the error between the influence coefficient F0 and the reference influence coefficient. Since S6 is performed, the accuracy of balance correction after the balance correction step S6 and, if necessary, step S6 is improved.

(C) Since the reference rotary machine and the measurement target rotary machine are the same model, the target rotary body 13 of the measurement target rotary machine is cut using the reference influence coefficient for the reference rotary body 13 of the reference rotary machine. This means that the balance of the target rotating body 13 is corrected. Therefore, the cutting in the cutting step S <b> 2 can serve as both a step for obtaining the influence coefficient of the target rotating body 13 and a step for correcting the unbalance of the target rotating body 13.

(D) By cutting the target rotating body 13 using the influence coefficient of the target rotating body 13 calculated in the coefficient calculating step S4, the balance of the measurement target rotating machine can be corrected with high accuracy. Moreover, since the balance of the target rotating body 13 of the measurement target rotating machine has already been corrected in the above-described cutting step S2, the balance accuracy of the target rotating body 13 is further increased in the balance correcting step S6. In addition, after the balance correction step S6, when the balance of the target rotating body 13 of the measurement target rotating machine is corrected by the influence coefficient method, the number of corrections can be reduced.

[Example]
FIG. 6 shows a case where the influence coefficient acquisition device 10 according to the above-described embodiment is applied to a supercharger 20 as a rotating machine.

  As shown in FIG. 6, the rotating body 13 of the supercharger 20 includes a turbine blade 15 that is rotationally driven by exhaust gas from the engine, and a compressor blade that supplies compressed air to the engine by rotating integrally with the turbine blade 15. 17 and a rotating shaft 19 having a turbine blade 15 coupled to one end and a compressor blade 17 coupled to the other end. Moreover, the supercharger 20 has the stationary side member 21 which supports the rotary body 13 rotatably. In the example of FIG. 6, the stationary side member 21 is a bearing housing in which bearings 23 a and 23 b that rotatably support the rotating body 13 (rotating shaft 19) are incorporated. The supercharger 20 includes a turbine housing 25 that houses the turbine blades 15 therein, and a compressor housing (removed in FIG. 6) that houses the compressor blades 17 inside. The turbine housing 25 is formed with a flow path (scroll) through which a fluid for rotationally driving the turbine blades 15 flows. The turbine housing 25 is attached to the inside of the support body 3. The support 3 is configured so that the fluid that drives the turbine blade 15 can be supplied to the flow path of the turbine housing 25, and the fluid that has driven the turbine blade 15 can be discharged to the outside of the support 3.

  Further, the support 3 supports the bearing housing 21 via the turbine housing 25 or directly. In FIG. 6, the cutting target portion 13 a of the rotating body 13 is at the end portion on the compressor blade 17 side, and is a nut in this example. In FIG. 6, both the angle sensor 7 and the cutting device 11 are provided on the compressor blade 17 side. However, when the angle sensor 7 is used, the cutting tool 11 a of the cutting device 11 is retracted to a position where it does not interfere with the angle sensor 7. When the cutting device 11 is used, the angle sensor 7 is retracted to a position where it does not interfere with the cutting device 11.

  In FIG. 6, other configurations and operations of the influence coefficient acquisition apparatus 10 may be the same as those in the above-described embodiment. Moreover, you may acquire the influence coefficient of the rotary body 13 of the supercharger 20 with the influence coefficient acquisition method by the above-mentioned embodiment using the influence coefficient acquisition apparatus 10 shown in FIG.

  The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention.

3 support body, 5 acceleration sensor, 7 angle sensor,
9 calculator, 10 influence coefficient acquisition device, 11 cutting device,
11a cutting tool, 11b drive mechanism, 11c position controller,
13 Rotating body, 13a Cutting target

Claims (3)

An influence coefficient acquisition method for acquiring an influence coefficient indicating a vibration change of a rotating body relative to a rotation balance change of the rotating body,
A first vibration data acquisition step of acquiring first vibration data by measuring vibration of a support that supports the rotation body in a state where the rotation body is rotating;
A cutting step for giving a rotational balance change to the rotating body by cutting a part of the rotating body;
A second vibration data acquisition step of acquiring second vibration data by measuring the vibration of the support while the rotating body is rotating;
A coefficient calculation step for calculating an influence coefficient of the rotating body based on the first vibration data, the rotation balance change given in the cutting step, and the second vibration data; Acquisition method. A rotating machine different from the measuring object rotating machine having the rotating body, and preparing a reference rotating machine of the same model as the measuring object rotating machine,
Obtain the influence coefficient of the rotating body of the reference rotating machine as the reference influence coefficient,
Calculate the unbalanced data U1 from the reference influence coefficient,
The influence coefficient acquisition method according to claim 1, wherein in the cutting step, the rotating body is cut based on the unbalance data U1. An unbalance data calculation step of calculating unbalance data U0 from the influence coefficient calculated in the coefficient calculation step;
The method according to claim 2, further comprising: a balance correction step of cutting a rotating body of the rotating machine to be measured based on the unbalance data U <b> 0.

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