JPH1181902A - How to balance a turbine rotor - Google Patents

Abstract

(57) Abstract: Distances R1, R2,..., Rn from the center of rotation S to the center of gravity of the reference blade, assuming that the reference blade 20A is fitted or fitted in each groove 11 of the disk 10.
(N = the number of grooves), and a step of multiplying the weight Ws of the reference blade by the distances R1, R2... Rn to obtain vectors, and combining these vectors to obtain an unbalance vector U1 of the grooves. Determining the disk unbalance vector U2 by actually measuring the disk unbalance, measuring the weight of the turbine blade, combining the vector U1 and the vector U2, and referring to the combined vector U3, Blade 2
0. A method for balancing a turbine rotor, comprising: [Effect] In order to balance the turbine rotor, there is no need to cut the turbine rotor or add a weight, so that it is economical and efficient. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for balancing a turbine rotor.

[0002]

2. Description of the Related Art When a rotating body mounted on a shaft is rotated, a centrifugal force is generated due to the distributed mass of its constituent parts, and a resultant force of the centrifugal force acts on the shaft. If the resultant force is large, it causes the shaft to vibrate. Therefore, it is necessary to balance the rotating body. The method of balancing the turbine rotor is generally to correct the balance in an integrated state in which the blade is attached to the disk. In addition, for example, Japanese Patent Laid-Open No. 6-280502 discloses a "balance rotor". I have. As shown in FIG. 2 and FIG. 3 of the above publication, the annular array formed by the grooves 32 provided on the platform 26 of the airfoil wing 23 and the grooves 30 provided on the annular flange 31 of the disk 22. The holding plate 29 is mounted, but the balance is corrected by disposing the thin holding plate 29 in the unbalanced portion.

[0003]

In the above, the amount of unbalance is large, and a large disk must be cut or a large weight must be added. Disks subjected to high temperature and high stress are generally difficult-to-process materials and are expensive, so that the number of processing steps is increased and the problem in cost remains. In the above description, after all the airfoil wings 23 are mounted on the disk 22, the thin holding plate 29 can be attached to and detached from the annular array, but many ordinary holding plates 29 cannot be attached and detached and the airfoil wings 23 It is necessary to remove a part of the plate, and in order to achieve a precise balance, holding plates 29 having various thicknesses are required, which cannot be said to be an efficient balancing method.

The present inventors measure the unbalance amount of a single disk, measure the unbalance amount of a single turbine blade, and arrange the turbine blades so as to cancel the unbalance of the single disk. Although the balance of the turbine was implemented, good balance correction results could not be obtained even with this, and after attaching the turbine blade to the disk, it was necessary to take the classic method of replacing the turbine blade after checking the balance, Balancing man-hour did not decrease.

[0005]

The present inventors have examined the above method in detail, and as a result, have found that there is not a small variation in the disk groove, and this variation hinders the balance correction. Then, when a balancing method considering the variation of the disk groove was devised, the balance could be corrected satisfactorily in a few steps. More specifically, claim 1 of the present invention provides a method for fitting or assuming that the reference blade is fitted into each groove of the disk, and distances R1, R2,... Rn (n = n) from the center of rotation to the center of gravity of the reference blade.
Measuring the number of grooves) and the weight W of the reference blade.
s is multiplied by the distances R1, R2... Rn to obtain a vector, and these vectors are combined to obtain a groove unbalance vector U1, and the disk unbalance is measured to obtain a disk unbalance vector U2. Combining the step U, the step of actually measuring the weight of the turbine blade, and the vector U1 and the vector U2,
Arranging the turbine blades with reference to the composite vector. Since the correction is performed in consideration of the disk groove, the balance can be corrected satisfactorily. It is economical and efficient because it is not necessary to cut the turbine rotor or add weight to balance the turbine rotor.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings should be viewed in the direction of reference numerals.

FIG. 1 is a sectional view of a turbine rotor according to the present invention. The turbine rotor 1 has a disk 10 and turbine blades (hereinafter referred to as “blades”) 20. Consists of Reference numeral 2 denotes a shaft hole.

FIG. 2 is an exploded perspective view of the turbine rotor according to the present invention. The disk 10 has disk grooves 11 formed at equal intervals on the outer periphery. Blade 2
0 denotes a wing 21 and a shroud 22 at the tip of the wing 21
And a platform 23 at the root of the wing 21 and a stepped tree-shaped base 24 formed below the platform 23. The base 24 is a portion that fits into the disk groove 11. 20A is a reference blade. The reference blade 20A is an average blade with respect to the dimensions and weight of the blades 20..., And may be an actual blade or an assumed blade, and is used for calculating a groove unbalance vector U1 described later. This is the reference blade. The position of the center of gravity of the reference blade 20A is C, and the lower end 25A of the base 24A and the position of the center of gravity C
Let G be the distance to. To facilitate the following explanation,
It is assumed that the position C of the center of gravity is on a line that intersects a plane of symmetry perpendicular to the front surface 26A of the base 24A and a center plane between the front and rear surfaces of the base 24A.

FIG. 3 is an explanatory view of the method of measuring the center of gravity of the reference blade fitted into the disk groove from the center of the disk according to the present invention. The measurement is performed by replacing the position of the disk groove 11 with the center of gravity of the reference blade. Things. A disc groove position measurement (actually, the position of the center of gravity of the reference blade fitted in the disc groove) is carried out by a jig 30, which has a mounting shaft 31 fitted in the shaft hole 2 at the center of rotation of the disc 10, , A disk groove position measuring unit 40 mounted on the upper part of the frame 32, and a disk groove direction measuring unit 50 mounted on the lower part of the frame 42
Consists of

The disk groove position measuring section 40 is provided with a frame 32
The upper support member 32a which extends horizontally to the upper part of the upper part, and the inverted L-shaped holding members 41, 41 attached to the upper support member 32a
And guide members 42 attached to the holding members 41, 41,
42, a blade master 45 having a T-shaped support portion 43 guided by the guide members 42, 42 as an upper portion and a base portion 44 fitted in the disk groove 11 as a lower portion, and a T-shaped support portion 4
3 and a compression spring 46 provided between the upper support member 32a;
A dial gauge 47 attached to the center of the upper end of the frame 32 with the measuring end 47a applied to the T-shaped support portion 43. The blade master 45 measures the distance from the lower end 44a of the base 44 of the blade master 45 to the upper surface 43a of the horizontal portion of the T-shaped support 43, and the distance G from the lower end 25A of the base of the reference blade 20A to the center of gravity C (see FIG. 2). It is what it was. Also, the lower surface of the upper horizontal portion of the inverted L-shaped holding members 41, 41 is
1a, the upper surface of the horizontal portion of the T-shaped support portion 43 is 43a, the lower surface is 43b, and the vertical member is 43c.

The disk groove direction measuring unit 50
A lower support member 32b extending horizontally to a lower portion of the disk 2; an angle measuring member 51 having one surface (a measurement surface) 51a passing through the center of the lower support member 32b and the center T of the mounting shaft 31; And a reference line member 52 capable of aligning one reference surface 52a with the reference line K. Reference line member 5
Reference numeral 2 denotes a plate-like member having an indicator pin 53 on a line extending toward the outer periphery through the center of the attachment shaft 31 and having a surface passing through the center T of the attachment shaft 31 and the indicator pin 53 as a reference surface 52a. .

The disc groove position measuring jig 30 is arranged such that the mounting shaft 31 is fitted into the shaft hole 2 (see FIG. 1) of the disk 10 so that the center T of the mounting shaft 31 is
0, the rotation center S of the blade master 45
Is fitted in the disk groove 11 so that the disk 10
Is measured from the center of rotation S to the center of gravity C (see FIG. 2) of the reference blade 20A, which is assumed to be fitted into the disk groove 11, and the direction of the center of gravity C from the reference line K.

The measurement of the position of the center of gravity of the reference blade is as follows.
The measuring end 47a of the dial gauge 47 is aligned with the horizontal lower surface 41a of the inverted L-shaped holding members 41, 41, the pointer of the dial gauge 47 at that time is set to 0 (zero), and then the measuring end 47 is set.
a is applied to the upper surface 43a of the horizontal portion of the T-shaped support portion 43, and the reading N of the pointer of the dial gauge 47 at that time is read, and the lower surface 44a of the base portion 44 of the blade master 45 is read from the upper surface of the horizontal portion of the T-shaped support portion 43. G to the distance to 43a
(See FIG. 3), the distance between the center of the mounting shaft 31 and the lower surface 41a of the horizontal portion of the inverted L-shaped holding members 41, 41 is L.
Then, the distance R from the center of gravity position C (see FIG. 2) of the reference blade 20A assumed to fit in the disk groove 11 to the rotation center S of the disk 10 is obtained from LN.

To measure the center of gravity of the reference blade, the indicator pin 53 provided on the reference line member 52 is aligned with the reference line K, and the angle between the reference surface 52a of the reference line member 52 and the measurement surface 51a of the angle measuring member 51 is measured. by measuring θ,
The direction of the disk groove 11 with respect to the reference line K defined on the surface of the disk 10 is obtained.

FIG. 4 is a diagram during measurement of the unbalance vector (the amount and direction of unbalance) of the disk according to the present invention. The balance measuring device 60 includes a gantry 61 and the gantry 6.
1 includes a displacement bearing portion 62, 63, a rotating shaft 64 rotatably supported by the displacement bearing portion 62, 63, and an electric motor 65 for driving the rotating shaft 64. In addition,
The balance measuring device 60 is an arbitrary surface perpendicular to the rotation axis 64 of the object (disk 10) (hereinafter referred to as a “correction surface”).
That. ) Measures the unbalance amount and direction (unbalance vector) of BB.

Next, a method of balancing the turbine rotor described above will be described. The balance of the rotating body is to balance the centrifugal force of each part. If the centrifugal force is F, F is represented by the following equation. F = mrω ² where, m: mass of the rotating body, r: distance from the center of the rotation axis, ω: angular velocity of the rotating body, and m = W / g, where W: weight of the rotating body g: acceleration of gravity Therefore, the centrifugal force F becomes F = (W / g) rω ² . However, since ω ² / g is constant in each part, if W · r of each part is balanced, the centrifugal force F of each part is balanced, and the rotating body is balanced. Therefore,
The unbalance vector is represented by W · r. Since the vector is inconvenient in calculation, the x-direction component and the y-direction component of this vector are actually calculated on the xy rectangular coordinates and added or subtracted.

FIG. 5 is a flowchart of a method for balancing a turbine rotor according to the present invention, which will be described below with reference to the flowchart. The unbalance amounts U1 to U
5 and the distances R1, R2... Are vectors, and their sizes (scalars) are also U1 to U5 and R1, R2.

Step 1: The distance R from the rotation center S to the center of gravity of the reference blade is measured assuming that the reference blade 20A is fitted into each groove 11 of the disk 10 (see FIG. 3). The measured distances are R1, R2... R59, and the directions from the disc reference position are θ1, θ2. The number of grooves n is 59.

Step 2: To the weight Ws of the reference blade,
Direction θ from disk reference position measured in step 1
The respective vectors are obtained by multiplying the distances R1, R2... R59 toward 1, θ2... Θ59, and these vectors are combined to obtain the groove unbalance vector U1. U1 = Ws (R1 + R2 +... + R59) In the actual calculation, the x-direction component U1x and the y-direction component U1y of the groove unbalance vector are calculated. U1x = Ws (R1cosθ1 + R2cosθ2 +... +
R59 cos θ59) U1y = Ws (R1 sin θ1 + R2 sin θ2 +... +
R59 sin θ59)

Step 3: Disk 1 with balance measuring machine
An unbalance vector U2 of 0 is actually measured. The correction surface is
S- of the middle surface of the front and rear surfaces of the disk in FIG.
S-plane. Assuming that the unbalance amount of the disk 10 is U2 and the direction of the unbalance is an angle 基準 2 from the reference position, the x-direction component U of the unbalance vector of the disk
The 2x and y direction components U2y are as follows: U2x = U2cosΘ2 U2y = U2sinΘ2.

Step 4: Measure the weight of each blade 20. Measure the weight of the blade from the lighter
W2 ... W59.

Step 5: Steps 2 and 3 above
The vector U1 and the vector U2 obtained in the above are combined to calculate a combined vector U3. U3 = U1 + U2 In the actual calculation, the x-direction component U3x and the y-direction component are calculated respectively U3y. U3x = U1x + U2x U3y = U1y + U2y

Step 6: The turbine blades 20 are arranged in the grooves 11 with reference to the composite vector U3 obtained in Step 5 described above. In an actual calculation, the x-direction component U3x and the y-direction component U3y obtained in step 5 are synthesized,
A combined unbalance vector U3 is obtained, and based on the combined unbalance vector U3, that is, a blade that is lighter in the direction in which the combined unbalance vector U3 exists,
Also, a heavy blade in the opposite direction is placed in each groove. Specifically, with the groove in the U3 direction as the center, the light blade W
Are arranged in each groove, and heavy blades W59 are arranged in each groove around the groove in the direction opposite to U3.
Similarly to the directions θ1, θ2,.
.. R59, the unbalance vector U4 is determined from the groove position and the blade weight. U4x = W1R1 + W2R2 +... + W59R59 In actual calculation, the x-direction component U4x and the y-direction component U4y of the unbalance vector U4 are calculated. U4x = W1R1cosθ1 + W2R2cosθ2 + ...
+ W59R59cosθ59 U4y = W1R1sinθ1 + W2R2sinθ2 + ...
+ W59R59sinθ59 This arrangement of the blades is
This is the maximum balance addition by the blade to the unbalance synthesis by the disk groove.

Step 7: The vectors U2 and U4 obtained in Step 3 and Step 6 are combined to calculate an unbalance vector U5 of the entire turbine rotor. U5 = U2 + U4 In an actual calculation, the x-direction component and the y-direction component are respectively added. U5x = U1x + U4x U5y = U1y + U4y

Step 8: The unbalance vector U5 of the entire turbine rotor obtained in Step 7 is set to the allowable value U.
Check if it is within 0. In the calculation at the time of U5 ≦ U0, the x-direction component U5x and the y-direction component U5y
And checks whether U5 is within the allowable value U0.

[0026]

(Equation 1)

In this case, a good balance has been achieved.

Step 9 If U5> U0, each blade weight W1.
And the groove position dimensions M1... M59 are reexamined. For example, W1 and W59 are exchanged, and the above steps 6 to 9 are recalculated to confirm whether U5 falls within the allowable value. According to this result, W1 and W2 and W59 and W
It is considered whether to replace W58 or only W2 and W58 again, and to enter an allowable value, or to repeat until the unbalance amount U5 reaches the minimum value. FIG. 6 is a diagram showing an unbalance vector of each unit according to the present invention described above.

FIG. 7 is an explanatory view of another embodiment of the method of calculating the position of the center of gravity of the reference blade fitted into the groove from the center of the disk according to the present invention. In this calculation method, the distance P between the bottom 11a of the groove of the disk 10 and the axis S is actually measured, and assuming that the reference blade 20A (see FIG. (See FIG. 2), the distance Q from the center S of the disk to the center of gravity C of the reference blade is calculated, and the angle θ between the reference line SK and the line S-11a is calculated.
Is a method of actually measuring. The calculated Q dimension is shown in FIG.
Step 2 is calculated as the dimension. Disk groove 11
This position is used when the bottommost portion 11a of the groove can be represented. Therefore, it is used when there is a correlation between the R dimension and the P dimension shown in FIG. The measurement of the P dimension is a simple measurement of the length, and a specific description of the measurement method is omitted.

The dimensions from the lower end 25 of the base 24 of the blade 20 to the position of the center of gravity C are fixed.
This is because the influence is small because it is much smaller than the dimension from the center of rotation S to the position of the disk groove 11. However, when balancing is performed more precisely, the distance from the base 24 of each blade 20 to the position C of the center of gravity is adjusted. The dimensions may be measured, the groove position dimension M may be corrected, and the calculation in step 6 may be performed. If the position of the center of gravity C of the blade 20 is not on a plane of symmetry perpendicular to the front surface 24b of the base 24, the groove direction angle θ is corrected and the calculation in step 6 is performed. Also, the blade 20
Is not on the line that intersects the middle plane of the front and rear surfaces of the base 24, the steps from step 1 to step 9 can be performed with the plane passing through the center of gravity C and perpendicular to the axis as the correction plane. I just need. In the case where the two-stage turbine rotor is integrated, the two surfaces perpendicular to the shaft hole 2 passing through the center of gravity position C of the blade 20 of each stage of the turbine rotor are modified surfaces, and the above-described steps are performed for each of the two surfaces. The balance may be obtained by performing the procedures from 1 to 9.

[0031]

According to the present invention, the following effects are exhibited by the above configuration. In the method for balancing a turbine rotor according to claim 1, distances R1, R2,..., Rn (n = grooves) from the center of rotation to the center of gravity of the reference blade are provided on the assumption that the reference blade is fitted into or fitted to each groove of the disk. ), And the distances R1, R2,.
Multiplying Rn to obtain a vector, and combining these vectors to obtain a groove unbalance vector U1;
Determining the disk unbalance vector U2 by actually measuring the disk unbalance; measuring the weight of each turbine blade;
And a step of arranging the turbine blades with reference to the synthesized vector, and correcting the balance in consideration of the disk groove, so that the balance can be satisfactorily corrected. Further, there is no need to cut the turbine rotor or add a weight to balance the turbine rotor, which is economical and efficient.

[Brief description of the drawings]

FIG. 1 is a sectional view of a turbine rotor according to the present invention.

FIG. 2 is an exploded perspective view of a turbine rotor according to the present invention.

FIG. 3 is an explanatory view of a method of measuring a center of gravity position of a reference blade fitted into a disk groove from the center of the disk according to the present invention.

FIG. 4 is a diagram during measurement of an unbalance vector of the disk according to the present invention.

FIG. 5 is a flowchart of a turbine rotor balancing method according to the present invention.

FIG. 6 is a diagram showing an unbalance vector of each unit according to the present invention.

FIG. 7 is an explanatory view of another embodiment of the method of calculating the position of the center of gravity of the reference blade fitted into the groove from the center of the disk according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Turbine rotor, 10 ... Disk, 11 ... Groove (disk groove), 20 ... Turbine blade, 20A ... Reference blade, 30 ... Jig for groove position measurement.

Claims (1)

[Claims] A step of actually measuring distances R1, R2... Rn (n = number of grooves) from the center of rotation to the center of gravity of the reference blade, assuming or assuming that the reference blade is fitted into each groove of the disk; Multiplying the weight Ws of the reference blade by the distances R1, R2,... Rn to obtain a vector, synthesizing these vectors to obtain a groove unbalance vector U1, and measuring the disk unbalance to measure the disk unbalance. Obtaining a balance vector U2, measuring the weight of the turbine blade, and combining the vector U1 and the vector U2, and arranging the turbine blade with reference to the combined vector to balance the turbine rotor. Method.