CN115752147A - Method for repairing non-cylindricity defect of steam turbine rotor shaft neck - Google Patents

Abstract

The present invention provides a method for repairing non-cylindrical defect of steam turbine rotor journal. The repair method includes the following steps: S1, measuring the diameter and straightness of the rotor before repair and dividing the rotor journal maintenance area; S2, applying special grinding tooling Installed in the journal maintenance area to grind and polish the rotor journal; S3. After the repair of the rotor journal, remove the grinding tooling and measure the journal size with an outer micrometer to ensure that the diameter of the rotor journal meets the tolerance requirements; S4. Installation For the bearing bush, the straightness and end face circular runout of the rotor journal under different phases are measured by measuring tools to ensure that the straightness and end face circular runout meet the tolerance requirements. The invention can repair the non-cylindricity of the rotor shaft journal without returning to the factory for maintenance, ensures the use accuracy, and has the advantages of short period and low cost.

Description

A method for repairing non-cylindrical defect of steam turbine rotor journal

technical field

The invention mainly relates to the related technical field of steam turbine repair, in particular to a method for repairing non-cylindrical defects of a steam turbine rotor journal.

Background technique

The steam turbine is used in power generation projects and is located between the generator and the condenser. The high-pressure end of the steam turbine is output from the shaft, and the shaft of the steam turbine and the generator shaft are connected by a self-synchronizing coupling. During actual use, it is necessary to regularly check the key factory data of the steam turbine. When there is a deviation in the cylindricity of the journal of the electric end of the medium and low voltage rotors, it needs to be repaired in time. For example, the applicant of this application found that the journal of the electric end of the middle and low voltage rotors in the project was not cylindrical by 0.045mm, which exceeded the specified 0.02mm, which is a serious deviation, so it needs to be dealt with in time.

In the prior art, if the problem of cylindricity is encountered, the solution is to return to the factory or find a local large-scale machining factory for turning, and reassemble the bearing bush. If the investigation finds that during the new installation process of power plant A and No. 1 unit, the shaft journal is not up to standard, and the on-site repair of the main engine factory does not meet the requirements of the regulations, and it is still returned to the factory for processing. After returning to the factory, the journal is turned and the bearing shell is reassembled. The OEM promises to provide non-standard bearing bush spare parts in the future.

In the above treatment plan, it is necessary to dismantle the medium and low pressure cylinders on site, return the medium and low pressure rotors to the factory for turning, and reassemble the bearing bushes according to the size of the repaired journal after turning, which will lead to a long time period and extremely high cost. The estimated cost is about 100 Ten thousand, the cycle is about 65 days. It is less feasible because it requires a complete shutdown of the on-site host installation work. Therefore, the applicant of the present application proposes to repair the non-columnar problem by manual grinding. In the grinding process, if sandpaper is directly used for grinding, it is difficult to control the angle and strength, and the situation after repairing cannot be controlled, and the space of the bearing room is small, the grinding space is not enough, and the feasibility is low. Therefore, it is necessary to design an effective The repair method is to solve the problem of non-cylindrical defects of the shaft journal of the steam turbine.

Contents of the invention

In order to solve the deficiencies of the current technology, the present invention combines the existing technology and proceeds from practical applications to provide a method for repairing the non-cylindrical defect of the rotor journal of a steam turbine, which can repair the non-cylindrical defect of the rotor journal without returning to the factory for maintenance. It is repaired to ensure the accuracy of use, and has the advantages of short cycle and low cost.

To achieve the above object, the technical scheme of the present invention is as follows:

A method for repairing non-cylindrical defects of a steam turbine rotor journal, said repair method comprising the following steps:

S1. Measure the diameter and straightness of the rotor before repair and divide the repair area of the rotor journal;

S2. Install the special grinding tool in the journal maintenance area to grind and polish the rotor journal,

Wherein, the grinding tooling includes two independent half-ring hoops, sandpaper is pasted on the inner circle of the two half-ring hoops, and the two half-ring hoops are fastened by a binding belt wound on the outer circle. There is a pull rope connected to the hoop, and the operator pulls the rope to rotate the half hoop to grind the rotor journal;

S3. After the repair of the rotor journal is completed, the grinding tool is removed, and the journal size is measured with an outer micrometer to ensure that the diameter of the rotor journal meets the tolerance requirements;

S4. Install the bearing bush, and measure the straightness and end face circular runout of the rotor journal under different phases with measuring tools to ensure that the straightness and end face circular runout meet the tolerance requirements.

Wherein, the measuring tool includes a set of guide rails arranged on one side of the rotor and a gauge, the gauge is mounted on the set of guide rails, and the set of guide rails is mounted on the middle surface of the bearing seat.

Further, step S2 specifically includes:

S21. Install 120-mesh sandpaper in the two half-ring hoops respectively, erect the half-ring hoops on the rotor shaft journal, and tighten the two half-ring hoops to a suitable strength with a tightening belt;

S22. Two operators reciprocally pull the pull rope on both sides of the rotor to drive the half-ring hoop to rotate evenly, and grind the rotor journal with sandpaper. During the grinding process, monitor the tightening force of the half-ring hoop, and increase the tightening force in time if the strength is insufficient;

S23. Loosen the binding belt every 5 minutes, measure the size of the journal in the grinding area, if the size does not reach the set size, replace with new sandpaper and continue grinding until the size of the journal reaches the set size;

S24. Change the type of sandpaper to 150 mesh, repeat the grinding process, and move the half ring hoop repeatedly in the axial direction until the surface finish of the journal reaches Ra0.4.

Further, in step S21, control the tightening strength of the binding band so that the tightening strength at the large end of the taper of the journal is slightly greater than that at the small end of the taper. .

Further, in step S22, each pull requires that the half-circle hoop has a rotation angle of not less than 120 degrees, and the rotation frequency is about 30 times per minute.

Further, the material of the half ring hoop is nylon.

Further, multiple pressing grooves are provided on each half-encircling hoop, and the pressing grooves are arranged along the contour of the outer circular surface of the half-encircling hoop, and the binding band is wound in the pressing grooves.

Further, the length of the sandpaper satisfies: extending from the inner circle of the half-ring hoop to the mid-section plane of the half-ring hoop, so that the sandpaper can be fixed by the pressing plate arranged at the mid-section plane, and the mid-section of the pressing plate and the half-ring hoop The planes are connected by fastening screws.

Further, the measuring tool specifically includes a transition plate, a guide rail, a supporting plate and a table. The transition plate is arranged on one side of the rotor and fixedly connected to the middle surface of the bearing housing. The guide rail is fixedly connected to the transition plate by bolts. The supporting plate and the guide rail Sliding fit, the table is set on the supporting plate;

In step S4, measure the straightness of the outer circle of the repaired journal on the basis of the outer circles of the thrust discs on both sides of the rotor journal. During the measurement process, first adjust the supporting plate to make it parallel to the rotor axis, and then measure the straightness by means of a table.

Further, in step S4, the measurement method specifically includes the following steps:

S41. Take any point on the outer circle of the thrust disc on both sides, point A and point B, the distance between AB and AB is L0, measure the diameter of the outer circle of these two points, record them as A0 and B0 respectively, calculate the difference and divide it by 2, denoted as C0;

S42. Install the transition plate on the middle surface of the bearing housing through the connecting bolts;

S43. Erect the guide rail on the transition plate, attach the watch to the surface of the supporting plate, and control the distance between the watch and the rotor so that the watch needle is in contact with the surface of the rotor;

S44. Slightly fix the guide rail through the fixing bolts, and the reading on the meter will not change greatly when the pallet is manually shaken;

S45. Push the supporting plate to move along the guide rail, touch the pointer of the gauge on one side of the thrust inventory A, and clear the reading of the gauge;

S46. Push the supporting plate to move along the guide rail, touch the pointer of the gauge to the thrust inventory B on the other side, and record the reading of the gauge as D0;

S47. Calculate the deviation value of the parallelism between the supporting plate and the rotor axis, and record it as E0, E0=ARCTAN((D0-C0)/L0);

S48. Tap the guide rail with a copper rod to make it swing at a certain angle, continue to push the supporting plate and take point A as 0 to observe the reading on the meter at point B, and repeat the above operations until the reading on the meter is D0=C0;

S49. Tighten the guide rail connecting bolts symmetrically;

S410. Continue to push the supporting plate and take point A as the zero point to observe the reading on the meter at point B, and confirm that the parallelism of the supporting plate is parallel to the axis of the rotor at this time;

S411. Bring the pointer of the gauge into contact with the outer circle of the journal, and take the leftmost outer circle as the zero point, push the supporting plate to measure the reading jump of the gauge on the outer circle of the journal, and the maximum value is the straightness deviation value;

S412. Rotate the rotor, and measure the journal straightness of different phases.

Further, in step S412, the rotor is rotated in units of 30 degrees to measure the straightness of the rotor journals of 360 degrees and 12 phases, so as to ensure that the straightness of the rotor journals of the 12 phases all meet the design dimensions.

Beneficial effects of the present invention:

1. For the first time, the present invention proposes to solve the non-cylindrical problem of the steam turbine rotor journal by manual grinding. With the design of special grinding tooling, the grinding of the rotor journal can be completed quickly and with high precision, so that it can meet the size requirements. Practice has proved that, Through the method provided by the invention, the repairing of the cylinder is not required, and the grinding accuracy and effect can be guaranteed.

2. The repair method provided by the present invention cooperates with the design of the special grinding tool. In the repair of the rotor bearing, the overall cost is small and the grinding accuracy can be guaranteed. Through the provided special measuring tools and measuring methods, the high precision of the repaired rotor journal can be realized , Fast measurement to ensure the reliability of the measurement size.

Description of drawings

Accompanying drawing 1 is a step diagram of the repair method of the present invention;

Accompanying drawing 2 is a schematic diagram of the structure of the grinding tool of the present invention;

Accompanying drawing 3 is the structural schematic diagram II of the grinding tool of the present invention;

Accompanying drawing 4 is the structural schematic diagram of the measuring tool of the present invention.

Labels shown in the accompanying drawings:

1. Half ring hoop; 2. Sandpaper; 3. Press plate; 4. Handle; 5. Compression groove; 6. Fastening screw.

Detailed ways

The present invention will be further described in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined in the present application.

This embodiment provides a method for repairing the non-cylindrical defect of a steam turbine rotor journal, which is mainly used for repairing the non-cylindrical problem of the rotor journal. In this embodiment, the restoration steps are mainly shown in FIG. 1 .

First, measure the diameter and straightness of the rotor before repair and divide the repair area of the rotor journal:

The on-site measurement of the low-voltage rotor electric end journal does not have a cylindricality of 0.045mm, so there is a large error, and the area with a large error is found out from the measurement as the maintenance area for repair.

Second, repair by manual grinding:

At present, the medium and low pressure rotors of the generator set are already in place in the bearing housing, and the space of the bearing housing is narrow. Therefore, the out-of-tolerance parts of the rotor are repaired in the bearing housing by grinding and hooping. For this purpose, a special grinding tool is designed in this embodiment. , for journal grinding.

The structure of the special grinding tool provided in this embodiment is shown in Fig. 2 and Fig. 3 .

It mainly includes two independent half-ring hoops 1, the width of the half-ring hoop 1 is 100mm, the gap between the inner circle and the journal is 0.5mm on one side, and the thickness is 50mm. Sandpaper 2 is pasted on the inner surface of the half-ring hoop 1, and a handle 4 for installing a rope is arranged on the outer surface of each half-ring hoop 1. Two half-ring hoops 1 are wrapped around the half-ring The fastening strap on the outer surface of hoop 1 is fastened. The base material of the half ring hoop 1 is nylon, which can protect the journal during grinding. After the handle 4 is installed with the rope, the staff pulls the rope at a constant speed to make the half ring hoop 1 rotate and pass through the inner sandpaper 2 to the journal surface. Grind.

In this embodiment, four compression grooves 5 are also provided on each half-encircle hoop 1, the compression grooves 5 are arranged along the outline of the outer circular surface of the half-encircle hoop 1, and the binding belt is arranged in the compression groove 5, During the construction, the special binding belt is wound in the pressing groove 5, and the tightening force of the special binding belt is controlled, so that the fastening pressure can be evenly distributed on the surface of the sandpaper 2, and at the same time, the upper and lower semi-axial alignment of the half ring hoop 1 can be achieved. effect.

In this embodiment, the handle 4 is fixedly connected to the outer circle of the half-ring hoop 1 through fasteners, and the handle 4 is set at the center of the outer circle of the half-ring hoop 1 to ensure uniform force during the grinding process.

In this embodiment, the sandpaper 2 is fixed on the inner side of the half-ring hoop 2 through the pressure plate 3. Specifically, the sandpaper 2 is extended outward from the inner surface of the half-ring hoop 1 to the middle plane of the half-ring hoop 1, and the middle There is a pressure plate 3 at the parting plane, and the pressure plate 3 is fixedly connected to the half-ring hoop 1 through the fastening screw 6, and then the sandpaper 2 is pressed and fixed, which can ensure that the sandpaper 2 will not be trapped in the half-ring hoop 1 due to the small friction coefficient during grinding. skidding.

The grinding tool provided in this embodiment completes the grinding of the rotor journal through the following process.

Process 1, install 120-mesh sandpaper 2 on the upper and lower halves of the half-encircling hoop 1, set up the half-encircling hoop 1 on the area to be repaired on the journal, and control the tightening force of the binding belt by cross-wrapping the tightening bands, at the large end of the taper of the journal The tightening force at this position is slightly greater than that at the small end of the taper, and it is advisable that the clamping force at the entire section can be pushed by the operator to rotate with a little force.

Process 2. Two people stand on both sides of the rotor and pull the handle 4 back and forth to drive the hoop to rotate evenly to ensure stable force during the movement. Each pull requires the hoop to have a rotation angle of not less than 120 degrees, and the rotation frequency is about 30 times per minute. During the grinding process, pay attention to monitoring the tightness of the hoop, and increase the tightening force in time if the hoop is found to be insufficient.

Step 3, loosen the special binding belt for winding every 5 minutes, measure the journal size of the grinding area, if the measured size does not reach the required size, replace the new sandpaper, move the hoop to the area to be polished, tighten the binding belt, and continue Pull the hoop back and forth to grind the journal, and repeat the above process until the measured size of the journal reaches the required size.

Step 4, polishing, replace the sand paper with 150 mesh, repeat the above process, and move the hoop repeatedly in the axial direction until the surface finish of the journal reaches Ra0.4.

After the journal is repaired by grinding tooling, inspection is carried out: first remove the half ring hoop 1, and measure the journal size with an outer micrometer to ensure that the diameter of the repaired rotor journal meets the design requirements of a tolerance of 0.02mm.

Finally, install the bearing bush, use a special measuring tool to measure the straightness of the journal and the circular runout of the end face, rotate the rotor in units of 30 degrees, and use a turning tool to measure the straightness of the rotor journal with 12 phases at 360 degrees to ensure the straightness and shaft The neck runout meets the design requirement of 0.02mm.

In this embodiment, in order to facilitate measurement and ensure measurement accuracy, a special measurement tool is designed.

As shown in Figure 4, the measuring tool mainly includes a transition plate 7, a guide rail 15, a supporting plate 8 and a table 9, wherein the transition plate 7 is installed on the middle parting surface of the bearing seat 14 through the transition plate fastening screw 11, and the guide rail 15 is fixed on the transition plate 7 by bolts 10, the supporting plate 8 is installed on the guide rail 15 and can slide in the axial direction, and is mounted on the supporting plate 8 by the surface 9 adsorption.

Since the outer circle of the journal and the thrust plates on both sides (thrust plate A12 and thrust plate B13 in the figure) are processed on the same rotation basis, the axes of the three sections of the outer circle coincide theoretically and are all the axis of the rotor body. Therefore, the outer circle of the thrust discs on both sides (thrust disc A12, and thrust disc B13) is used as a reference on site to measure the straightness of the outer circle of the journal after grinding.

The measurement steps of the measurement tool are as follows.

(1) As shown in Figure 4, take any point on the outer circle of the thrust discs (thrust disc A12 and thrust disc B13) at both ends, point A and point B, and the distance between AB and AB is L0, and measure the diameter of the outer circle of these two points , respectively recorded as A0, B0, calculate the difference and divide by 2, recorded as C0;

(2) The transition plate 7 is installed on the middle parting surface of the bearing seat 14 through the transition plate fastening screw 11;

(3) Install the guide rail 15 on the transition plate 7, attach the gauge 9 to the surface of the supporting plate 8, and control the distance between the gauge 9 and the rotor so that the gauge needle contacts the surface of the rotor;

(4) The guide rail 15 is slightly fixed by the bolt 10, and the reading on the meter will not change greatly when the supporting plate 8 is manually shaken;

(5) Push the supporting plate 8, touch the pointer of the meter to the thrust inventory A on one side, and clear the reading of the meter;

(6) Push the supporting plate 8, touch the pointer of the meter to the thrust inventory B on the other side, and record the reading of the meter as D0;

(7) At this time, the deviation value of the parallelism between the supporting plate 8 and the rotor axis can be calculated, and recorded as E0, E0=ARCTAN((D0-C0)/L0); therefore, we make the reading D0=C0 by means of the meter, that is, Indicates that the supporting plate 8 is parallel to the rotor axis at this time;

(8) Tap the guide rail 15 with a copper rod to make it swing at a certain angle, continue to push the supporting plate 8 and take point A as the zero point to observe the reading on the meter at point B, and repeat the above operations until the reading on the meter is D0=C0;

(9) Tighten the bolts 10 symmetrically, and observe the reading on the meter; before the bolt 10 is fully tightened, if the reading on the meter changes, continue to push the supporting plate 8 with point A as zero and observe the reading on the meter at point B, and calibrate the supporting plate 8 again Parallelism, and finally tighten the bolt 10;

(10) Continue to push the supporting plate 8 and take the point A as the zero point to observe the reading on the meter at point B, and confirm that the parallelism of the supporting plate 8 is parallel to the rotor axis at this time;

(11) Put the pointer of the gauge in contact with the outer circle of the journal, and take the leftmost outer circle as the zero point, push the supporting plate 8 to measure the reading jump of the gauge on the outer circle of the entire journal, and the maximum value is the straightness deviation value;

(12) Rotate the rotor to measure the straightness of the journal in different phases.

In the actual measurement process, the rotor is rotated at a unit of 30 degrees and the straightness of the rotor journal of 360 degrees and 12 phases is measured with the above tools. The measurement proves that the repaired rotor journal straightness and journal runout test results conform to the shaft The design requirement of neck straightness is 0.02mm.

Claims (10)

1. a steam turbine rotor journal non-cylindrical defect repair method, it is characterized in that, the repair method comprises the steps: S1. Measure the diameter and straightness of the rotor before repair and divide the repair area of the rotor journal; S2. Install the special grinding tool in the journal maintenance area to grind and polish the rotor journal, Wherein, the grinding tooling includes two independent half-ring hoops, sandpaper is pasted on the inner circle of the two half-ring hoops, and the two half-ring hoops are fastened by a binding belt wound on the outer circle. There is a pull rope connected to the hoop, and the operator pulls the rope to rotate the half hoop to grind the rotor journal; S3. After the repair of the rotor journal is completed, the grinding tool is removed, and the journal size is measured with an outer micrometer to ensure that the diameter of the rotor journal meets the tolerance requirements; S4. Install the bearing bush, and measure the straightness and end face circular runout of the rotor journal under different phases with measuring tools to ensure that the straightness and end face circular runout meet the tolerance requirements. Wherein, the measuring tool includes a set of guide rails arranged on one side of the rotor and a gauge, the gauge is mounted on the set of guide rails, and the set of guide rails is mounted on the middle surface of the bearing seat. 2. The steam turbine rotor journal non-cylindrical defect repair method according to claim 1, characterized in that, step S2 specifically comprises: S21. Install 120-mesh sandpaper in the two half-ring hoops respectively, erect the half-ring hoops on the rotor journal, and tighten the two half-ring hoops to an appropriate strength with a tightening belt; S22. Two operators reciprocally pull the pull rope on both sides of the rotor to drive the half-ring hoop to rotate evenly, and grind the rotor journal with sandpaper. During the grinding process, monitor the tightening force of the half-ring hoop, and increase the tightening force in time if the strength is insufficient; S23. Loosen the binding belt every 5 minutes, measure the size of the journal in the grinding area, if the size does not reach the set size, replace with new sandpaper and continue grinding until the size of the journal reaches the set size; S24. Change the type of sandpaper to 150 mesh, repeat the grinding process, and move the half ring hoop repeatedly in the axial direction until the surface finish of the journal reaches Ra0.4. 3. The method for repairing non-cylindrical defect of steam turbine rotor journal according to claim 2, characterized in that, in step S21, the tightening force of the binding band is controlled so that the tightening force at the large end of the taper of the journal is slightly greater than At the position of the small end of the taper, the tightening strength of the entire section should be such that the operator can push the hoop to rotate with a little force. 4. The method for repairing non-cylindrical defects of steam turbine rotor journals according to claim 2, characterized in that, in step S22, each pull requires that the half-circle hoop has a rotation angle of not less than 120 degrees, and the rotation frequency is about 30 times per minute. 5. The method for repairing non-cylindrical defects of steam turbine rotor journal according to claim 1, characterized in that, the material of the half ring hoop is nylon. 6. The method for repairing non-cylindrical defects of steam turbine rotor journals according to claim 1, characterized in that, each half-ring hoop is also provided with multiple compression grooves, and the compression grooves are arranged along the outside of the half-ring hoop. The contour of the circular surface is set, and the binding band is wound in the pressing groove. 7. The method for repairing the non-cylindrical defect of the steam turbine rotor journal according to claim 1, wherein the length of the sandpaper satisfies: extending outward from the inner circle of the half-ring hoop to the mid-section plane of the half-ring hoop, so that The sandpaper can be fixed by a pressing plate arranged at the middle split plane, and the pressing plate is connected with the middle split plane of the half hoop by fastening screws. 8. The method for repairing the non-cylindrical defect of the steam turbine rotor journal according to claim 1, wherein the measuring tool specifically includes a transition plate, a guide rail, a supporting plate and a table, and the transition plate is arranged on one side of the rotor and fixed Connected to the middle surface of the bearing seat, the guide rail is fixedly connected to the transition plate through bolts, the supporting plate and the guiding rail are slidingly matched, and the table is set on the supporting plate; In step S4, measure the straightness of the outer circle of the repaired journal on the basis of the outer circles of the thrust discs on both sides of the rotor journal. During the measurement process, first adjust the supporting plate to make it parallel to the rotor axis, and then measure the straightness by means of a table. 9. The steam turbine rotor journal non-cylindrical defect repair method according to claim 8, characterized in that, in step S4, the measuring method specifically comprises the following steps: S41. Take any point on the outer circle of the thrust disc on both sides, point A and point B, the distance between AB and AB is L0, measure the diameter of the outer circle of these two points, record them as A0 and B0 respectively, calculate the difference and divide it by 2, denoted as C0; S42. Install the transition plate on the middle surface of the bearing housing through the connecting bolts; S43. Erect the guide rail on the transition plate, attach the watch to the surface of the supporting plate, and control the distance between the watch and the rotor so that the watch needle is in contact with the surface of the rotor; S44. Slightly fix the guide rail through the fixing bolts, and the reading on the meter will not change greatly when the pallet is manually shaken; S45. Push the supporting plate to move along the guide rail, touch the pointer of the gauge on one side of the thrust inventory A, and clear the reading of the gauge; S46. Push the supporting plate to move along the guide rail, touch the pointer of the gauge to the thrust inventory B on the other side, and record the reading of the gauge as D0; S47. Calculate the deviation value of the parallelism between the supporting plate and the rotor axis, and record it as E0, E0=ARCTAN((D0-C0)/L0); S48. Tap the guide rail with a copper rod to make it swing at a certain angle, continue to push the supporting plate and take point A as 0 to observe the reading on the meter at point B, and repeat the above operations until the reading on the meter is D0=C0; S49. Tighten the guide rail connecting bolts symmetrically; S410. Continue to push the supporting plate and take point A as the zero point to observe the reading on the meter at point B, and confirm that the parallelism of the supporting plate is parallel to the axis of the rotor at this time; S411. Bring the pointer of the gauge into contact with the outer circle of the journal, and take the leftmost outer circle as the zero point, push the supporting plate to measure the reading jump of the gauge on the outer circle of the journal, and the maximum value is the straightness deviation value; S412. Rotate the rotor, and measure the journal straightness of different phases. 10. The method for repairing non-cylindrical defect of steam turbine rotor journal according to claim 9, characterized in that, in step S412, the rotor is rotated at a unit of 30 degrees to measure the straightness of the rotor journal with 12 phases at 360 degrees to ensure The straightness of the rotor journals of the 12 phases all meet the design dimensions.

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