Installation Method of Motor Slip Ring

Abstract

The present invention relates to the field of motor installation methods, and in particular to a new method for installing a motor slip ring. The installation method includes the following steps: a. Select a spare slip ring that meets the standards; b. Then clean the surface of the shaft head of the rotating shaft; c. Next, install a guide rod on the shaft head of the rotating shaft, and the end of the guide rod is a conical head; d. The slip ring is fixedly connected to the outer side of the top plate of the guiding tooling, and then the top plate and the slip ring as a whole are heated; e. Slip the slip ring onto the guide rod so that the slip ring is coaxial with the rotating shaft, then rotate the slip ring to make the Teflon insulation stud label on the slip ring correspond to the label on the motor cable, and then slip the slip ring onto the shaft shoulder of the rotating shaft; f. Finally, remove the guide rod and the top plate after the slip ring cools to the ambient temperature. The present invention can greatly improve the success rate of hot sleeving the slip ring, shorten the sleeving time after the slip ring is heated, save the motor maintenance time, improve the motor maintenance level, and ensure the smooth progress of the C6 repair of the HXN5 locomotive.

Description

Technical Field

[0001] The present invention relates to the field of motor installation methods, and in particular to a method for installing a motor slip ring. Background Art

[0002] When newly manufacturing the main and auxiliary generators of HXN5 locomotives and performing C5 and even C6 repairs, the slip rings are assembled with the rotating shaft by means of hot shrinking. Except for our company which uses the horizontal installation method, the other two newly manufacturing and maintenance companies both use the vertical installation method. The advantages of horizontal installation are that it occupies less motor maintenance site and has a short maintenance time. The original hot shrinking process was to heat at 165 ± 5 °C for 6 hours, and a guiding column was used for hot shrinking the rotating shaft. The success rate of hot shrinking was low, less than 50% (even lower in summer, less than 40%). This not only affected the production cycle, but also repeatedly disassembled and assembled the slip ring, easily damaging the mating surface between the slip ring and the rotating shaft. This slip ring is an imported part, which is not only expensive, but also has a long procurement cycle.

[0003] Due to the low success rate of the original hot shrinking process, in order to reduce the amount of rework, there is a phenomenon of increasing the heating temperature and heating time of the slip ring on site. Affected by the insulating material in the slip ring, long-term exposure to high temperature will accelerate the insulation aging, thereby reducing the insulation of the slip ring and resulting in a high short-circuit failure rate of the slip ring, greatly affecting the company's reputation. The C6 repair of HXN5 locomotive is a key project of the company, with high requirements for quality and cycle. However, the production cycle of the main and auxiliary generators of HXN5 seriously restricts the production cycle of the C6 repair of HXN5 locomotive. Therefore, it is urgent to solve the problem of slip ring installation and improve the maintenance quality of the motor. Summary of the Invention

[0004] In order to overcome the deficiency of the existing installation method with low success rate, the present invention provides a method for installing a motor slip ring.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a method for installing a motor slip ring, including the following steps:

[0006] a. Select a qualified slip ring for standby;

[0007] b. Then clean the surface of the shaft head of the rotating shaft;

[0008] c. Next, install a guiding rod on the shaft head of the rotating shaft, and the end of the guiding rod is a conical head;

[0009] d. The slip ring is fixedly connected to the outside of the top plate of the guiding tooling, and then the top plate and the slip ring are heated integrally;

[0010] e. Slip the slip ring onto the guiding rod to make the slip ring coaxial with the rotating shaft, then rotate the slip ring to make the Teflon insulation stud label on the slip ring correspond to the label on the motor cable, and then slip the slip ring onto the shaft shoulder of the rotating shaft;

[0011] f. Finally, after the slip ring has cooled down to the ambient temperature, remove the guide rod and the top plate.

[0012] According to another embodiment of the present invention, it further includes that in step d, when there are still 35 - 50 minutes left for the slip ring to be heated, place the cooling sleeve into liquid nitrogen for cooling for 20 - 30 minutes, then put the cooling sleeve on the rotating shaft for cooling for 15 - 25 minutes. During the cooling process, cover the cooling sleeve with asbestos. After the rotating shaft has been cooled, remove the cooling sleeve, and then install the heated slip ring sleeve onto the rotating shaft.

[0013] According to another embodiment of the present invention, it further includes that in step c, the guide rod is composed of a rod body and a circular plate. The rod body is vertically fixed at the center of the circle of the circular plate, and the circular plate is fixedly connected to the shaft head through bolts. The diameter of the guide rod is smaller than that of the rotating shaft.

[0014] According to another embodiment of the present invention, it further includes that in step d, the slip ring is sent into an oven for heating. The heating temperature is 170 - 180 °C, and the heating time is 5 - 6.5 hours.

[0015] According to another embodiment of the present invention, it further includes that in step d, the top plate of the guiding tooling is fixedly connected to the slip ring through bolts.

[0016] According to another embodiment of the present invention, the cooling sleeve is in a U shape.

[0017] The beneficial effects of the present invention are that the present invention can greatly improve the success rate of hot - sleeving the slip ring, shorten the sleeving time after the slip ring is heated, save the motor maintenance time, improve the motor maintenance level, and ensure the smooth progress of the C6 maintenance of the HXN5 locomotive. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following further describes the present utility model in conjunction with the drawings and embodiments.

[0019] Figure 1 is a schematic structural view of the guide rod of the invention;

[0020] Figure 2 is a schematic structural view of the top plate of the invention;

[0021] Figure 3 is a schematic structural view of the cooling sleeve of the invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] As Figure 1 is a schematic structural view of the guide rod of the invention, Figure 2 is a schematic structural view of the top plate of the invention, Figure 3 is a schematic structural view of the cooling sleeve of the invention. Embodiment

[0023] The installation steps of the motor collector ring are as follows: 1. Measure the collector ring gear and the inner diameter of the collector ring, and select a collector ring that meets the standards for backup. 2. Clean the shaft head and check if there are burrs on the bearing. If not, use sandpaper to remove them. 3. Use 4 0.5" bolts to install the guide rod on the shaft head. Do not tighten the bolts. Adjust the position of the guide fixture and the shaft head so that the column head of the guide rod is concentric with the shaft head and the outer surface of the column head is slightly smaller than the shaft head. Use a gasket to place it axially vertically on the outer surface of the shaft and the column head of the guide rod, and observe that the gap around the column head is uniform. Tighten the four bolts on the shaft head, and use a gasket to re-measure the gap between the guide rod and the shaft head surface for uniformity. 4. Install the top plate of the guide fixture on the outside of the collector ring, tighten the two fixing screws, place asbestos on the oven tray, place the collector ring on the oven tray and send it to the oven for heating. The heating temperature is 170℃, and the heating and insulation time is 6 hours in total. If the ambient temperature exceeds 20℃, it is allowed to use liquid nitrogen to cool the shaft for heat sleeve. The specific operation is as follows: At a distance of 150℃ from the collector ring out of the oven, At 45 minutes, place the cooling jacket in a cooling barrel, pour liquid nitrogen into the barrel that covers the jacket, add liquid nitrogen at intervals to ensure that the liquid nitrogen covers the cooling jacket, and the cooling time is 25 minutes; put the cooling jacket into the shaft, cover the entire cooling jacket with asbestos, and the cooling time is 20 minutes; remove the cooling jacket and wipe the shaft head of the shaft with clean cotton yarn. 5. Use two lifting ropes to symmetrically hang the collector ring, adjust the height and position of the collector ring, and put the collector ring into the guide rod to make it coaxial with the shaft. 6. Turn the collector ring so that the Teflon insulation stud label on the collector ring corresponds to the label on the motor cable, and loosen the lifting rope. 7. Quickly put the collector ring on the shaft and push it to the shoulder of the spindle. When installing, pay attention to the correspondence between the stud label on the collector ring and the motor cable. After the collector ring cools to ambient temperature, remove the guide tooling.

[0024] Combined with Figure 1 and attached Figure 2 As shown, the end of the guide rod is a tapered end, and the inner hole of the collector ring is a tapered hole. When the guide rod passes through the inner hole of the collector ring, the tapered end of the guide rod first passes through the smaller tapered hole opening in the collector ring, and then passes through the opening on the top plate at the other end of the collector ring, so that the collector ring can always remain stable during the process of installing the guide rod.

[0025] The temperature selection method for the heating collector ring is to first calculate the theoretical value:

[0026] Expansion Δψ=0.000012×ψ×Δt

[0027] Where Δψ-expansion mm

[0028] 0.000012 is the thermal expansion coefficient / °C (expansion coefficient of steel material) [2]

[0029] ψ- is the nominal diameter of the heated workpiece (mm)

[0030] Δt - is the temperature rise during heating in °C

[0031] According to the relevant data of the slip ring and the shrink fit, take ψ = 95.15 mm and Δψ = 0.101 mm (the interference of the slip ring shrink fit is 0.052 - 0.101 mm).

[0032] Then the temperature rise Δt = 0.101÷0.000012÷95.15≈88.5 °C

[0033] According to experience, there should be a margin for the expansion amount during shrink fit. If we relax by 6 wires, that is, take Δψ = 0.16 mm, then the temperature rise Δt = 0.16÷0.000012÷95.15≈140 °C. According to a temperature difference of 140 °C, in summer when it is hot, the heating temperature of the slip ring should be at least 180 °C. The maximum shrink fit temperature of the original slip ring process is 170 °C. In winter when the temperature is around zero, the temperature difference between the slip ring and the rotating shaft is large, so the success rate of shrink fit is higher than that in summer. After researching other motor maintenance companies, it is learned that the maximum heating temperature of the slip ring is 220 °C, but there are greater risks at high temperatures and it is not advisable. In order to increase the temperature difference between the rotating shaft and the slip ring, that is, the size difference between the outer diameter of the rotating shaft and the inner hole of the slip ring, while heating the slip ring, use liquid nitrogen to cool the shaft head. After comprehensive analysis and discussion, considering the insulation grade of the slip ring, we set the heating temperature of the slip ring at 175±5 °C and cool the shaft head to -10 °C. Then the temperature difference between the two components is more than 185 °C, that is, the relative expansion amount of the slip ring reaches more than 0.2 mm, exceeding twice the interference of the slip ring. In theory, it should fully meet the requirements of shrink fit. We designed a special liquid nitrogen cooling tooling and changed the slip ring installation process to: set the heating temperature of the slip ring at 175±5 °C, heat for 6 hours, use liquid nitrogen to cool the shaft head to -10 °C for assembly, and track and count the installation of slip rings on 10 vehicles. The statistical parameters include motor number, diameter of the slip ring section of the rotating shaft, inner diameter of the slip ring, interference, ambient temperature, etc. The interference is basically 0.08, and the shrink fit was successful for 7 motors, with a success rate of 70%.

[0034] After multiple repeated tracking tests, two key factors affecting the success rate of slip ring shrink fit were found: 1. The relative expansion amount of the slip ring should be large enough, that is, the temperature difference between the rotating shaft and the slip ring is large. 2. When installing the slip ring, the center lines of the slip ring and the rotating shaft should coincide. Using liquid nitrogen to cool the shaft increases the success rate of slip ring shrink fit, indicating that the verification of the first key point is effective. In order to make the success rate of slip ring shrink fit even higher, next we need to solve the second key factor.

[0035] As shown in the attachment Figure 3 The cooling sleeve is a U - shaped body, and the two open ends of the cooling sleeve are attached to the rotating shaft.

[0036] The inner hole of the slip ring is stepped. When using the original tooling guide, whether the slip ring is installed horizontally or vertically, there is a large deviation between the two center lines. Therefore, it is necessary to redesign the slip ring installation tooling to control the deviation between the slip ring center and the shaft center within 0.05mm, and the slip ring installation problem is solved. Using many years of experience in motor maintenance and research on slip ring structure, we designed several sets of shrink fit tooling. After field practical application, we finally designed the most effective new guide tooling, which controls the deviation of the center lines of the two components within 0.03mm when installing the slip ring.

[0037] Embodiment 2: The installation steps of the motor collector ring are as follows: 1. Measure the collector ring gear and the inner hole diameter of the collector ring, and select a collector ring that meets the standard for standby use. 2. Clean the shaft head of the rotating shaft and check if there are burrs on the bearing. If not, use sandpaper to grind and remove them. 3. Use 4 0.5” bolts to install the guide rod on the shaft head. Do not tighten the bolts. Adjust the position of the guide fixture and the shaft head so that the column head of the guide rod is concentric with the shaft head and the outer surface of the column head is slightly smaller than the shaft head. Use a gasket to place it axially vertically on the shaft and the outer surface of the guide rod column head, and observe that the gap around the column head is uniform. Tighten the four bolts on the shaft head, and use a gasket to re-measure the gap between the guide rod and the shaft head surface for uniformity. 4. Install the top plate of the guide fixture on the outside of the collector ring, tighten the two fixing screws, place asbestos on the oven tray, place the collector ring on the oven tray and send it to the oven for heating. The heating temperature is 180℃, and the heating and insulation time is 5 hours in total. If the ambient temperature exceeds 20℃, it is allowed to use liquid nitrogen to cool the shaft for heat sleeve. The specific operation is as follows: At a distance of 150℃ from the collector ring out of the oven, After 35 minutes, place the cooling jacket in a cooling barrel, pour liquid nitrogen into the barrel that covers the jacket, and add liquid nitrogen at intervals to ensure that the liquid nitrogen covers the cooling jacket. The cooling time is 20 minutes; put the cooling jacket into the shaft, cover the entire cooling jacket with asbestos, and the cooling time is 15 minutes; remove the cooling jacket and wipe the shaft head of the shaft with clean cotton yarn. 5. Use two lifting ropes to symmetrically hang the collector ring, adjust the height and position of the collector ring, and put the collector ring into the guide rod to make it coaxial with the shaft. 6. Turn the collector ring so that the Teflon insulation stud label on the collector ring corresponds to the label on the motor cable, and loosen the lifting rope. 7. Quickly put the collector ring on the shaft and push it to the shoulder of the spindle. When installing, pay attention to the correspondence between the stud label on the collector ring and the motor cable. After the collector ring cools to ambient temperature, remove the guide tooling. Example

[0038] The installation steps of the motor collector ring are as follows: 1. Measure the collector ring gear and the inner diameter of the collector ring, and select a collector ring that meets the standards for backup. 2. Clean the shaft head and check if there are burrs on the bearing. If not, use sandpaper to remove them. 3. Use 4 0.5” bolts to install the guide rod on the shaft head. Do not tighten the bolts. Adjust the position of the guide fixture and the shaft head so that the column head of the guide rod is concentric with the shaft head and the outer surface of the column head is slightly smaller than the shaft head. Use a gasket to place it axially and vertically on the outer surface of the shaft and the column head of the guide rod, and observe that the gap around the column head is uniform. Tighten the four bolts on the shaft head, and use a gasket to re-measure the gap between the guide rod and the shaft head surface for uniformity. 4. Install the top plate of the guide fixture on the outside of the collector ring, tighten the two fixing screws, place asbestos on the oven tray, place the collector ring on the oven tray and send it to the oven for heating. The heating temperature is 180℃, and the heating and insulation time is 6.5 hours in total. If the ambient temperature exceeds 20℃, it is allowed to use liquid nitrogen to cool the shaft for heat sleeve. The specific operation is as follows: at a distance of 100℃ from the collector ring out of the oven, When there are 50 minutes, place the cooling jacket in a cooling barrel, pour liquid nitrogen into the barrel that covers the jacket, and add liquid nitrogen at intervals to ensure that the liquid nitrogen covers the cooling jacket. The cooling time is 30 minutes; put the cooling jacket into the shaft, cover the entire cooling jacket with asbestos, and the cooling time is 25 minutes; remove the cooling jacket and wipe the shaft head of the shaft with clean cotton yarn. 5. Use two lifting ropes to symmetrically hang the collector ring, adjust the height and position of the collector ring, and put the collector ring into the guide rod to make it coaxial with the shaft. 6. Turn the collector ring so that the Teflon insulation stud label on the collector ring corresponds to the label on the motor cable, and loosen the lifting rope. 7. Quickly put the collector ring on the shaft and push it to the shoulder of the spindle. When installing, pay attention to the correspondence between the stud label on the collector ring and the motor cable. After the collector ring cools to ambient temperature, remove the guide tooling.

Claims

1. A method for installing a motor slip ring, characterized in that, It includes the following steps: a. Select a spare slip ring that meets the standards; b. Then clean the surface of the shaft head of the rotating shaft; c. Next, install the guide rod on the shaft head of the rotating shaft, and the end of the guide rod is a conical head; d. The slip ring is fixedly connected to the outside of the top plate of the guiding tooling, and then the top plate and the slip ring are heated as a whole; e. Slip the slip ring onto the guide rod to make the slip ring coaxial with the rotating shaft, then rotate the slip ring to make the Teflon insulation stud label on the slip ring correspond to the label on the motor cable, and then slip the slip ring onto the shaft shoulder of the rotating shaft; f. Finally, remove the guide rod and the top plate after the slip ring cools down to the ambient temperature; In step d, when there are still 35 - 50 minutes left for the slip ring to be heated, place the cooling sleeve in liquid nitrogen for cooling for 20 - 30 minutes, then slip the cooling sleeve onto the rotating shaft for cooling for 15 - 25 minutes. During the cooling process, cover the cooling sleeve with asbestos. After the rotating shaft is cooled, remove the cooling sleeve, and then install the heated slip ring sleeve onto the rotating shaft; In step c, the guide rod is composed of a rod body and a circular plate. The rod body is vertically fixed at the center of the circle of the circular plate, and the circular plate is fixedly connected to the shaft head by bolts. The diameter of the guide rod is smaller than the diameter of the rotating shaft; In step d, the slip ring is sent to an oven for heating. The heating temperature is 170 - 180 °C, and the heating time is 5 - 6.5 hours.

2. The method for installing a motor slip ring according to claim 1, characterized in that, In step d, the top plate of the guiding tooling is fixedly connected to the slip ring by bolts.

3. The method for installing a motor slip ring according to claim 1, characterized in that, The cooling sleeve is a U-shaped body.

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