A process for reaming the mounting hole of a rotor damping strip of a salient pole synchronous machine

Abstract

The present application relates to a kind of salient pole synchronous motor rotor damping strip installation hole reaming process, comprising the following steps: rough and fine progressive reaming process is used to damping strip installation hole, the rough and fine progressive reaming process includes a rough reaming process and at least one fine reaming process, a rough reaming process is carried out using a rough reaming broach, the rough reaming broach diameter is greater than the damping strip installation hole diameter before reaming 0.7±0.1mm, each fine reaming process is carried out using a fine reaming broach, the fine reaming broach diameter is greater than the rough reaming broach diameter, the value range is between 0.35±0.1mm to 0.50±0.1mm.The present application is simple and easy to operate, low in cost, the motor stable and safe operation period of the present application repair is completed at least can be maintained in five years or more, far higher than the existing motor normal operation period of only being able to maintain three months by replacing failed damping strip, while the present application can also greatly reduce the number of rotor core pulling.

Description

Technical Field

[0001] This invention relates to the field of hole enlargement technology, and in particular to a hole enlargement process for mounting holes of damping bars on rotors of salient-pole synchronous motors. Background Technology

[0002] The rotor of an existing salient-pole synchronous motor mainly consists of magnetic poles, excitation windings, damping bars, windings, and a shaft. Each magnetic pole is stamped from a steel plate with a thickness of 1-1.5mm. An excitation winding is fitted onto the magnetic pole. Several damping bar mounting holes are evenly distributed on the upper part of each magnetic pole core. Several damping bars are installed in the corresponding holes. The damping bars are bare copper rods. The damping bars pass through both ends of the magnetic pole core, and several copper busbars of the same material as the damping bars are fitted at both ends of the damping bars. The copper busbars are arranged and connected in sequence along the circumference to form a damping ring.

[0003] Based on production experience, large salient-pole synchronous motors in the roughing and finishing areas of existing hot rolling mills have been in operation for over a decade. Multiple on-site core inspections have revealed various wear and failure signs on the motor rotor damping bars, including breakage, thinning, burning, and loosening. The mounting holes for the cylindrical damping bars are severely deformed, and the inner walls of the damping bar mounting holes in the magnetic pole core exhibit uneven surface defects due to discharge factors. Although these surface defects can be repaired by grinding, grinding can easily increase the clearance between the damping bar and the mounting hole, making the damping bar even looser after installation. This can further increase the vibration of the damping bar during subsequent operation, significantly increasing the risk of damping bar breakage. Especially in the last five years, as motors have been running for longer periods, wear and failure phenomena such as loosening or breakage of the motor rotor damping bars have become increasingly serious. This situation not only reduces the motor's rapid response speed and the dynamic stability of the control system, but also increases the number of shutdowns due to comprehensive current faults reported by the control system, seriously affecting normal production. If the aforementioned technical faults or defects in the motor rotor damping bars are not eliminated in time, once the motor fault condition further develops and expands, it will cause distortion of the air gap magnetic field in the broken area of ​​the motor rotor damping bar, which will in turn cause abnormal current in the motor stator and rotor. This abnormal current situation can cause motor rotor oscillation at best, and at worst, it can cause the rotor damping bar to break and fly out of the rotor core slot, thereby damaging the stator and rotor windings, and ultimately causing major equipment failures such as main motor winding burnout, i.e., the burning out of the motor windings. Faced with such a serious adverse situation in practice, replacing the faulty motor with a backup motor would significantly increase the motor's operating costs. Replacing worn or failed damping strips on-site by removing the rotor core would require replacing the worn or failed damping strips annually. However, this repair method is not only time-consuming and labor-intensive on-site, but also carries high safety risks and cannot fundamentally solve the technical problems that cause the damping strips to wear or fail. Summary of the Invention

[0004] The technical problem solved by this invention is: when existing motor rotor damping bars become loose or broken, resulting in increased clearance between the damping bar and the mounting hole, how to repair the motor rotor to achieve long-term stable and safe operation of the motor.

[0005] This invention provides a process for enlarging the mounting hole of a damping strip on a salient-pole synchronous motor rotor, comprising the following steps: a progressive coarse-fine enlarging process is used for the mounting hole of the damping strip, the progressive coarse-fine enlarging process includes one coarse enlarging process and at least one fine enlarging process. The coarse enlarging process is performed using a coarse enlarging broach, the diameter of which is 0.7±0.1mm larger than the diameter of the mounting hole of the damping strip before enlarging. Each fine enlarging process is performed using a fine enlarging broach, the diameter of which is greater than the diameter of the coarse enlarging broach is within the range of 0.35±0.1mm to 0.50±0.1mm. The length of both the coarse enlarging broach and the fine enlarging broach is 200±10mm.

[0006] When existing motor rotor damping bars become loose or break, leading to increased clearance between the damping bar and its mounting hole, the usual approach is to replace the worn or failed damping bar. However, this repair method only maintains normal motor operation for about three months, thus failing to fundamentally solve the technical problem causing damping bar wear or failure. To address this, this invention employs a progressive rough-finish enlarging process for the motor rotor damping bar mounting hole, followed by selecting a damping bar of the appropriate size based on the enlarged hole dimensions to repair and reinstall the motor rotor. The enlarging process for repairing the motor rotor using this invention is simple, easy to implement, and inexpensive. Production practice has proven that motors repaired using this invention can maintain stable and safe operation for at least five years, far exceeding the three-month normal operation period achieved by replacing failed damping bars in existing technologies. Furthermore, this invention significantly reduces the number of rotor core extractions required for frequent short-term motor rotor repairs in existing technologies. Therefore, this invention has significant economic benefits and broad market application prospects.

[0007] Furthermore, it also includes preparatory work before enlarging the mounting hole of the damping strip, which includes the following steps: removing the peripheral equipment of the motor, installing and positioning the motor rotor, pulling out the damping strip of the motor rotor, and enlarging the mounting hole of the damping ring.

[0008] Furthermore, the hole for enlarging the damping ring mounting hole is performed using a drill bit. The diameter of the enlarged hole is 1 mm larger than the diameter of the enlarged hole for the damping strip mounting hole, so that the broach can pass through the damping ring mounting hole to perform the coarse and fine progressive hole enlarging process on the damping strip mounting hole.

[0009] Furthermore, when it is necessary to enlarge the mounting hole of the damping strip by 1mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and one fine enlargement process. The fine enlargement process is performed using a first fine enlargement broach, the diameter of which is 0.35±0.05mm larger than the diameter of the coarse enlargement broach.

[0010] Furthermore, when it is necessary to enlarge the mounting hole of the damping strip by 1.5mm, the progressive coarse and fine enlargement process includes one coarse enlargement process and two fine enlargement processes. The two fine enlargement processes are performed using two fine enlargement broaches, which include a second fine enlargement broach and a third fine enlargement broach. The diameter of the second fine enlargement broach is 0.35±0.1mm larger than the diameter of the coarse enlargement broach, and the diameter of the third fine enlargement broach is 0.5±0.05mm larger than the diameter of the second fine enlargement broach.

[0011] Furthermore, when it is necessary to enlarge the mounting hole of the damping strip by 2mm, the progressive coarse and fine enlargement process includes one coarse enlargement process and three fine enlargement processes. The three fine enlargement processes are performed using three fine enlargement broaches, namely a fourth fine enlargement broach, a fifth fine enlargement broach, and a sixth fine enlargement broach. The diameter of the fourth fine enlargement broach is 0.4±0.1mm larger than the diameter of the coarse enlargement broach, the diameter of the fifth fine enlargement broach is 0.5±0.1mm larger than the diameter of the fourth fine enlargement broach, and the diameter of the sixth fine enlargement broach is greater than the diameter of the fifth fine enlargement broach by a value ranging from 0.45±0.05mm to 0.5±0.05mm.

[0012] Furthermore, when it is necessary to enlarge the damping strip mounting hole with a diameter of 16mm by 1mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, and the diameter of the first fine enlarging broach is 17.05±0.05mm.

[0013] Furthermore, when it is necessary to enlarge the damping strip mounting hole with a diameter of 16mm by 1.5mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, the diameter of the second fine enlarging broach is 17.05±0.1mm, and the diameter of the third fine enlarging broach is 17.55±0.05mm.

[0014] Furthermore, when it is necessary to enlarge the damping strip mounting hole with a diameter of 16mm by 2mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, the diameter of the fourth fine enlarging broach is 17.10±0.1mm, the diameter of the fifth fine enlarging broach is 17.6±0.1mm, and the diameter of the sixth fine enlarging broach is 18.05±0.05mm.

[0015] Furthermore, when it is necessary to enlarge the damping strip mounting hole with a diameter of 20mm by 2mm, the diameter of the coarse enlarging broach is 20.7±0.1mm, the diameter of the fourth fine enlarging broach is 21.1±0.1mm, the diameter of the fifth fine enlarging broach is 21.6±0.1mm, and the diameter of the sixth fine enlarging broach is 22.1±0.05mm.

[0016] Furthermore, the broach is provided with a chip groove. During the hole enlargement process, compressed air is used to blow the chip groove, so that the iron chips on the chip groove can be quickly discharged along the chip removal groove of the damping strip on the outside of the motor rotor core. When the iron chips cause blockage, the broach must be withdrawn first, and then the hole enlarged again.

[0017] Specifically, the width of the chip removal groove of the external damping strip of the motor rotor core is 2-3mm. Attached Figure Description

[0018] Figure 1 This is a front view of the motor rotor involved in the hole-expanding process of the present invention.

[0019] Figure 2 for Figure 1 The image shows a left view of the motor rotor.

[0020] Figure 3 for Figure 1 The diagram shows an enlarged view of a local area I in the electronic rotor during hole enlargement using a broach.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1-Motor shaft; 2-Motor magnetic pole core; 3-Damping strip; 4-Damping strip chip removal groove on the outside of the core; 5-Damping strip mounting hole; 6-Broach; 7-Damping ring mounting hole; 8-Damping ring. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] In the description of this invention, it should be noted that the terms used in the various embodiments, such as "upper," "lower," "front," and "rear," which indicate orientation, are only used to simplify the description of the positional relationships based on the accompanying drawings and do not mean that the components and devices referred to must be operated in accordance with the specific orientations and defined operations, methods, and structures in the specification. Such directional terms do not constitute a limitation of this invention.

[0025] This invention provides a process for enlarging the mounting hole of the rotor damping bar in a salient-pole synchronous motor, as shown in the embodiment of the invention. Figure 3As shown, the process includes the following steps: a progressive coarse-finish reaming process is used to enlarge the damping strip mounting hole 5. The progressive coarse-finish reaming process includes one coarse reaming process and at least one fine reaming process. The coarse reaming process is performed using a coarse reaming broach, and the diameter of the coarse reaming broach is 0.7±0.1mm larger than the diameter of the damping strip mounting hole 5 before reaming. Each fine reaming process is performed using a fine reaming broach, and the diameter of the fine reaming broach is greater than the diameter of the coarse reaming broach by a value ranging from 0.35±0.1mm to 0.50±0.1mm. The lengths of both the coarse reaming broach and the fine reaming broach are 200±10mm.

[0026] In this embodiment, a progressive enlarging process is used to first enlarge the mounting hole 5 of the motor rotor damping strip, and then a damping strip 3 of the appropriate size is selected according to the size of the enlarged mounting hole 5 to complete the installation and repair. This enlarging process is simple, low-cost, and easy to implement. The motor after repair can maintain a stable and safe operating cycle of at least five years, which is much longer than the current three-month normal operating cycle of motors that can only be maintained by replacing the failed damping strip. At the same time, it can also significantly reduce the number of rotor core pulling required due to the current short-term and frequent repairs of motor rotors. Therefore, this invention has significant economic benefits and broad market application prospects.

[0027] Repeated production practice has shown that when the lengths of the roughing and finishing reaming broaches are shorter than 200±10mm, the resulting thicker chips cause difficulties in chip removal, thus affecting the reaming efficiency. Conversely, when the lengths of the roughing and finishing reaming broaches are longer than 200±10mm, the broaches are prone to breakage due to their excessive length, which also affects the reaming efficiency. Therefore, when both the roughing and finishing reaming broaches are 200±10mm in length, breakage of the broaches can be avoided while ensuring smooth chip removal, thereby guaranteeing both reaming accuracy and efficiency.

[0028] Optionally, such as Figures 1-3 As shown, it also includes preparatory work before enlarging the damping strip mounting hole 5. The preparatory work before enlarging the damping strip mounting hole 5 includes the following steps: removing the motor peripheral equipment, installing and positioning the motor rotor, pulling out the motor rotor damping strip 3, and enlarging the damping ring mounting hole 7.

[0029] Specifically, the peripheral equipment of the motor includes an external power supply line for the motor, a motor coupling, a speed measuring device, and upper covers and upper shells for the bearing seats on both sides of the motor.

[0030] Optionally, such as Figure 3As shown, the expansion of the damping ring mounting hole 7 is performed using a drill bit. The diameter of the expanded damping ring mounting hole 7 is 1 mm larger than the diameter of the expanded damping strip mounting hole 5, so that the broach 6 can pass through the damping ring mounting hole 7 to perform the coarse and fine progressive expansion process on the damping strip mounting hole 5.

[0031] Optionally, such as Figure 3 As shown, when it is necessary to enlarge the damping strip mounting hole 5 by 1mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and one fine enlargement process. The fine enlargement process is performed using a first fine enlargement broach, the diameter of which is 0.35±0.05mm larger than the diameter of the coarse enlargement broach.

[0032] Optionally, such as Figure 3 As shown, when it is necessary to enlarge the damping strip mounting hole 5 by 1.5mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and two fine enlargement processes. The two fine enlargement processes are performed using two fine enlargement broaches. The two fine enlargement broaches include a second fine enlargement broach and a third fine enlargement broach. The diameter of the second fine enlargement broach is 0.35±0.1mm larger than the diameter of the coarse enlargement broach, and the diameter of the third fine enlargement broach is 0.5±0.05mm larger than the diameter of the second fine enlargement broach.

[0033] Optionally, such as Figure 3 As shown, when it is necessary to enlarge the damping strip mounting hole 5 by 2mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and three fine enlargement processes. The three fine enlargement processes are performed using three fine enlargement broaches, namely a fourth fine enlargement broach, a fifth fine enlargement broach, and a sixth fine enlargement broach. The diameter of the fourth fine enlargement broach is 0.4±0.1mm larger than the diameter of the coarse enlargement broach, the diameter of the fifth fine enlargement broach is 0.5±0.1mm larger than the diameter of the fourth fine enlargement broach, and the diameter of the sixth fine enlargement broach is greater than the diameter of the fifth fine enlargement broach in the range of 0.45±0.05mm to 0.5±0.05mm.

[0034] Optionally, such as Figure 3 As shown, when it is necessary to enlarge the damping strip mounting hole 5 with a diameter of 16mm by 1mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, and the diameter of the first fine enlarging broach is 17.05±0.05mm.

[0035] Optionally, such as Figure 3As shown, when it is necessary to enlarge the damping strip mounting hole 5 with a diameter of 16mm by 1.5mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, the diameter of the second fine enlarging broach is 17.05±0.1mm, and the diameter of the third fine enlarging broach is 17.55±0.05mm.

[0036] Optionally, such as Figure 3 As shown, when it is necessary to enlarge the damping strip mounting hole 5 with a diameter of 16mm by 2mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, the diameter of the fourth fine enlarging broach is 17.10±0.1mm, the diameter of the fifth fine enlarging broach is 17.6±0.1mm, and the diameter of the sixth fine enlarging broach is 18.05±0.05mm.

[0037] Optionally, such as Figure 3 As shown, when it is necessary to enlarge the damping strip mounting hole 5 with a diameter of 20mm by 2mm, the diameter of the coarse enlarging broach is 20.7±0.1mm, the diameter of the fourth fine enlarging broach is 21.1±0.1mm, the diameter of the fifth fine enlarging broach is 21.6±0.1mm, and the diameter of the sixth fine enlarging broach is 22.1±0.05mm.

[0038] Optionally, such as Figure 3 As shown, the broach 6 is provided with a chip groove. During the hole enlargement process, compressed air is used to blow the chip groove, so that the iron chips on the chip groove can be quickly discharged along the chip removal groove 4 of the damping strip on the outside of the motor rotor core. When the iron chips blockage occurs, the broach 6 needs to be withdrawn first, and then the hole enlarged again.

[0039] Specifically, the width of the chip removal groove 4 of the external damping strip of the motor rotor core is 2-3mm.

[0040] Optionally, such as Figures 1-3 As shown, the hole enlargement process involves using a hole enlargement device to cut from the damping ring 8 at one end of the motor rotor to the damping ring 8 at the other end of the damping strip mounting hole 5 before hole enlargement. Two or more broaches 6 are configured according to the hole enlargement requirements to complete the hole enlargement of the damping strip mounting hole 5 in a progressive manner, from small to large, first coarse enlargement and then fine enlargement.

[0041] Specifically, such as Figures 1-3 As shown, each broach 6 has at least two feeds to ensure that the inner surface of the damping strip mounting hole 5 after the hole is enlarged has sufficient surface roughness. This facilitates the smooth completion of subsequent hole enlargement processes and also ensures that the damping strip 3 that is matched with the enlarged damping strip mounting hole 5 can be smoothly passed through and assembled to achieve a tight connection.

[0042] Optionally, such as Figure 1and Figure 2 As shown, after the damping strip mounting hole 5 is enlarged, a damping strip 3 of the corresponding size is installed through it. During the installation process, it should be ensured that both ends of the damping strip 3 pass through and extend beyond the outer ends of the damping ring 8. Then, the joint between the damping ring 8 and the damping strip 3 is welded and ground. After all the damping strips 3 are replaced, the motor rotor is cleaned, dried and painted. The motor rotor is then re-inserted, which is the reverse process of rotor core pulling. After that, the peripheral equipment is reinstalled and debugged.

[0043] While the present invention discloses the preferred embodiments described above, the present invention is not limited thereto. Those skilled in the art can make various arrangements and combinations of the above preferred embodiments to form complete technical solutions without departing from the spirit and scope of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A process for enlarging mounting holes for rotor damping bars in a salient-pole synchronous motor, characterized in that, The process includes the following steps: a progressive coarse-finish enlargement process is used for the damping strip mounting hole (5). The progressive coarse-finish enlargement process includes one coarse enlargement process and at least one fine enlargement process. The coarse enlargement process is performed using a coarse enlargement broach. The diameter of the coarse enlargement broach is 0.7±0.1mm larger than the diameter of the damping strip mounting hole (5) before enlargement. Each fine enlargement process is performed using a fine enlargement broach. The diameter of the fine enlargement broach is greater than the diameter of the coarse enlargement broach by a value ranging from 0.35±0.1mm to 0.50±0.1mm. The lengths of both the coarse enlargement broach and the fine enlargement broach are 200±10mm.

2. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 1, characterized in that, It also includes preparatory work before enlarging the damping strip mounting hole (5), which includes the following steps: removing the motor peripheral equipment, installing and positioning the motor rotor, pulling out the motor rotor damping strip (3) and enlarging the damping ring mounting hole (7).

3. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 2, characterized in that, The expansion of the damping ring mounting hole (7) is performed using a drill bit. The diameter of the expanded damping ring mounting hole (7) is 1 mm larger than the diameter of the expanded damping strip mounting hole (5).

4. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 1, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) by 1mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and one fine enlargement process. The fine enlargement process is carried out by a first fine enlargement broach, and the diameter of the first fine enlargement broach is 0.35±0.05mm larger than the diameter of the coarse enlargement broach.

5. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 1, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) by 1.5mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and two fine enlargement processes. The two fine enlargement processes are performed using two fine enlargement broaches. The two fine enlargement broaches include a second fine enlargement broach and a third fine enlargement broach. The diameter of the second fine enlargement broach is 0.35±0.1mm larger than the diameter of the coarse enlargement broach, and the diameter of the third fine enlargement broach is 0.5±0.05mm larger than the diameter of the second fine enlargement broach.

6. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 1, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) by 2mm, the coarse and fine progressive enlargement process includes one coarse enlargement process and three fine enlargement processes. The three fine enlargement processes are performed using three fine enlargement broaches. The three fine enlargement broaches include a fourth fine enlargement broach, a fifth fine enlargement broach, and a sixth fine enlargement broach. The diameter of the fourth fine enlargement broach is 0.4±0.1mm larger than the diameter of the coarse enlargement broach. The diameter of the fifth fine enlargement broach is 0.5±0.1mm larger than the diameter of the fourth fine enlargement broach. The value of the difference between the diameter of the sixth fine enlargement broach and the diameter of the fifth fine enlargement broach is between 0.45±0.05mm and 0.5±0.05mm.

7. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 4, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) with a diameter of 16mm by 1mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, and the diameter of the first fine enlarging broach is 17.05±0.05mm.

8. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 5, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) with a diameter of 16mm by 1.5mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, the diameter of the second fine enlarging broach is 17.05±0.1mm, and the diameter of the third fine enlarging broach is 17.55±0.05mm.

9. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 6, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) with a diameter of 16mm by 2mm, the diameter of the coarse enlarging broach is 16.7±0.1mm, the diameter of the fourth fine enlarging broach is 17.10±0.1mm, the diameter of the fifth fine enlarging broach is 17.6±0.1mm, and the diameter of the sixth fine enlarging broach is 18.05±0.05mm.

10. The process for enlarging the mounting hole of the rotor damping strip of a salient-pole synchronous motor according to claim 6, characterized in that, When it is necessary to enlarge the damping strip mounting hole (5) with a diameter of 20mm by 2mm, the diameter of the coarse enlarging broach is 20.7±0.1mm, the diameter of the fourth fine enlarging broach is 21.1±0.1mm, the diameter of the fifth fine enlarging broach is 21.6±0.1mm, and the diameter of the sixth fine enlarging broach is 22.1±0.05mm.

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