A Coupling Assembly Tool and Method for the Circulating Pump Gearbox of a Nuclear Power Plant

Abstract

The present invention belongs to the technical field of nuclear power maintenance, and particularly relates to an assembly tool and method for a coupling of a circulating pump gearbox in a nuclear power plant. The assembly tool is used for assembling a gearbox shaft and a coupling, and includes an upper guard plate, nut A, a screw rod, a jack, a lower guard plate, and nut B. The assembly method includes the following steps: Step 1: Transport the coupling to directly below the gearbox shaft, pass one end of four screw rods through the shaft holes of the coupling and then screw them into the bolt holes at the head of the gearbox shaft, and tighten them; Step 2: Install the upper guard plate under the coupling so that the four screw rods respectively pass through the long holes of the upper guard plate, and fix them with four nuts A; Step 3: Rotate the coupling so that the internal spline of the coupling just matches the external spline of the gearbox shaft. The assembly tool and method of the present invention effectively solve the assembly problem of high-precision components of the circulating pump gearbox coupling, reduce the demand for manpower and workload, and reduce the safety risk.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power plant maintenance, and particularly relates to an assembly tool and method for a coupling of a circulating water pump gearbox in a nuclear power plant. Background Art

[0002] The function of the circulating water system is to supply the necessary cooling water volume to the condenser of the steam turbine and the heat exchanger of the auxiliary cooling water system in the conventional island during the operation of the nuclear power unit. The seawater circulating pump of the circulating water system is the main active equipment of the circulating water system, and its function is to pressurize the cooling medium seawater and then transport it to the condenser. The concrete volute pump belongs to large equipment. In domestic nuclear power plants, generally each unit is usually equipped with 2 - 3 circulating water pumps working simultaneously, and no standby pump is provided. It can be seen that the stable and reliable operation of this pump is extremely important for the economy and safety of the nuclear power plant.

[0003] The circulating pump gearbox is a device that converts the high speed of the motor into the low speed required by the pump and plays a pivotal role. Since the coupling of the gearbox uses an interference fit for the upper and lower parts and has a spline connection in the middle, a large amount of manpower and material resources are required during the assembly process. At the same time, due to the spline plus interference fit, a high precision is required during the assembly process, and the existing assembly conditions cannot meet the above requirements.

[0004] Therefore, it is urgent to design an assembly tool and method to achieve high-precision assembly of the coupling of the circulating water pump gearbox in a nuclear power plant. Summary of the Invention

[0005] The purpose of the present invention is to provide an assembly tool and method for a coupling of a circulating water pump gearbox in a nuclear power plant to improve the precision and reliability of assembling the coupling of the circulating water pump gearbox in a nuclear power plant.

[0006] The technical solution of the present invention is as follows:

[0007] An assembly tool for a coupling of a circulating water pump gearbox in a nuclear power plant, used for assembling a gearbox shaft and a coupling, includes an upper guard plate, nut A, screw rod, jack, lower guard plate, and nut B;

[0008] The upper guard plate is of a circular plate structure, with a circular groove machined at the center position of its lower surface, and N through holes are arranged at equal intervals along the circumferential direction outside the circular groove, where N≥3;

[0009] The upper edge of the upper guard plate is clamped in the stop of the coupling;

[0010] The lower guard plate is of a circular plate structure, with a circular groove machined at the center position of its upper surface, and N through holes are machined at equal intervals along the circumferential direction outside the circular groove;

[0011] The jack is arranged between the circular groove of the upper guard plate and the circular groove of the lower guard plate;

[0012] There are N screws. One end extends out from the through hole of the upper guard plate, passes through the shaft hole of the coupling, and then screws into the bolt hole at the head of the gearbox shaft. The other end passes through the through hole of the lower guard plate.

[0013] A nut A is provided on the screw below the upper guard plate to fix the upper guard plate.

[0014] A nut B is provided on the screw below the lower guard plate to fix the lower guard plate and thus support the jack. By jacking up the jack, the upper guard plate moves slowly and smoothly upward.

[0015] Preferably, N long strip holes and N through holes are arranged at equal intervals along the circumferential direction on the outer side of the circular groove on the lower surface of the upper guard plate.

[0016] Preferably, N = 4.

[0017] Preferably, a sleeve is sleeved on the screw between the upper guard plate and the nut A to avoid damaging the lower surface of the upper guard plate during the process of rotating the nut A, and at the same time extend the operation space to the lower part of the coupling for more convenient rotation of the nut A.

[0018] Preferably, the screws are all full-thread bolts.

[0019] Preferably, the size of the circular groove on the upper guard plate is the same as the size of the jacking part of the jack, and the size of the circular groove on the lower guard plate is the same as the size of the base of the jack.

[0020] A method for assembling the coupling of the nuclear power plant circulating pump gearbox uses the assembling tool of the present invention.

[0021] A method for assembling the coupling of the nuclear power plant circulating pump gearbox includes the following steps:

[0022] Step 1: Transport the coupling to directly below the gearbox shaft. Pass one end of the four screws through the shaft hole of the coupling and then screw them into the bolt holes at the head of the gearbox shaft, and tighten them.

[0023] Step 2: Install the upper guard plate below the coupling, make the four screws pass through the long strip holes of the upper guard plate respectively, and fix them with four nuts A.

[0024] At the same time, rotate the four nuts A to make the coupling move upward slowly until the top of the internal spline on the coupling contacts the bottom of the external spline on the gearbox shaft.

[0025] Step 3: Rotate the coupling to make the internal spline of the coupling just match the external spline of the gearbox shaft.

[0026] Continue to rotate the four nuts A to make the coupling continue to move upward slowly until after the mating surface of the coupling contacts the mating surface of the gearbox shaft and can no longer move upward, stop rotating the nuts A.

[0027] Step 4: Disassemble one of the screws, pass it through the round hole of the upper guard plate and then reconnect it to the gearbox shaft, and then sequentially disassemble and replace the remaining screws.

[0028] Step 5: Slip the lower guard plate onto the bottom ends of the four screws and position it with nut B. Then place the jack in the round groove of the lower guard plate, rotate nut B to drive the lower guard plate upward, and at the same time move the jack upward and lock it in the round groove of the upper guard plate. Tighten nut B.

[0029] Step 6: Heat the outer surface of the coupling to make it expand thermally, increasing the gap between the mating surfaces of the coupling and the gearbox shaft, so that the coupling can continue to move upward.

[0030] Then pressurize the jack to slowly drive the upper guard plate and the coupling to move upward synchronously.

[0031] Step 7: When the coupling is properly installed on the gearbox shaft, keep the jack stationary and remove the tooling after the coupling has cooled.

[0032] Preferably, in step 4, after disassembling one of the screws, sequentially disassemble and replace one screw at the diagonal of the above-mentioned screw and the remaining two screws.

[0033] Preferably, in step 6, use a blowtorch to heat the outer surface of the coupling.

[0034] The remarkable effects of the present invention are as follows:

[0035] (1) The assembly tool and method of the present invention effectively solve the assembly problem of the high-precision components of the circulating pump gearbox coupling, reduce the manpower requirement and workload, and lower the safety risk.

[0036] (2) The assembly tool of the present invention is simple to operate, convenient and reliable, greatly reducing the complexity of assembling the circulating pump gearbox coupling, and at the same time reducing the risk of jamming caused by the interference fit between the coupling and the gearbox shaft.

[0037] (3) The assembly method of the present invention is simple, efficient, and the steps are carried out in one go, effectively reducing the assembly time.

[0038] (4) The long slot of the upper guard plate in the present invention facilitates the adjustment of the relative position between the coupling and the gearbox shaft. After the adjustment is completed, in order to prevent excessive swing of the upper guard plate during upward movement, the connecting hole of the screw can be replaced with a round hole to ensure that the upward movement swing is as small as possible, which has a remarkable application effect. Description of the Drawings

[0039] Figure 1 It is a schematic structural diagram of the assembly tool;

[0040] Figure 2Schematic diagram of the pump shaft position on the gearbox;

[0041] Figure 3 Schematic diagram of the coupling;

[0042] Figure 4 Schematic diagram of the upper guard plate;

[0043] Figure 5 Schematic diagram of the sleeve;

[0044] Figure 6 Schematic diagram of the nut;

[0045] Figure 7 Schematic diagram of the screw;

[0046] Figure 8 Schematic diagram of the jack;

[0047] Figure 9 Schematic diagram of the lower guard plate;

[0048] Figure 10 Cross-sectional view of the assembly tool.

[0049] In the figure: 1 lower cover plate of the gearbox, 2 gearbox shaft, 3 coupling, 4 upper guard plate, 5 sleeve, 6 nut A, 7 screw, 8 jack, 9 lower guard plate. Detailed implementation method

[0050] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] As Figures 1 to 9 shown, a coupling assembly tool for a nuclear power plant circulating pump gearbox is used to assemble the lower cover plate 1 of the gearbox, the gearbox shaft 2, and the coupling 3. The assembly tool includes an upper guard plate 4, a sleeve 5, a nut A 6, a screw 7, a jack 8, a lower guard plate 9, and a nut B.

[0052] The upper guard plate 4 has a circular plate structure. A circular groove is machined at the center position of its lower surface. Four long holes and four through holes are arranged at equal intervals along the circumferential direction outside the circular groove. The size of the circular groove is the same as the size of the jacking part of the jack 8, which is convenient for the jacking part of the jack 8 to cooperate with the upper guard plate 4 and ensures the smooth movement of the upper guard plate 4 driven by the jacking part of the jack 8 during the upward movement. The upper edge of the upper guard plate 4 is clamped in the stop of the coupling 3.

[0053] The lower guard plate 9 has a circular plate structure. A circular groove is machined at the center position of its upper surface. Four through holes are machined at equal intervals along the circumferential direction outside the circular groove. The size of the circular groove is the same as the size of the base of the jack 8, which is convenient for the jack 8 to be fixed on the lower guard plate 9.

[0054] The jack 8 is arranged between the circular groove of the upper guard plate 4 and the circular groove of the lower guard plate 9.

[0055] There are four described screws 7, all of which are through-thread bolts. One end extends out from the through-hole of the upper guard plate 4, passes through the shaft hole of the coupling 3, and then screws into the bolt hole at the head of the gearbox shaft 2. The other end passes through the through-hole of the lower guard plate 9.

[0056] The described sleeve 5 is of a cylindrical structure and is sleeved on the screw 7 between the upper guard plate 4 and the lower guard plate 9.

[0057] A nut A6 is provided on the screw 7 below the sleeve 5 to press the sleeve 5 against the lower surface of the upper guard plate 4.

[0058] A nut B is provided on the screw 7 below the lower guard plate 9 to fix the lower guard plate 9 and thus support the jack 8. By jacking up the jack 8, the upper guard plate 4 moves slowly and smoothly upward.

[0059] The described sleeve 5 can avoid damaging the lower surface of the upper guard plate 4 during the process of rotating the nut A6. At the same time, it improves the operating conditions where it is inconvenient to operate the wrench due to the small chamber space of the coupling 3, and extends the operating space below the coupling 3 to make it more convenient to rotate the nut A6.

[0060] A method for assembling the coupling of the nuclear power plant circulating pump gearbox uses the above-mentioned assembling tools for operation, including the following steps:

[0061] Step 1: Transport the coupling 3 directly below the gearbox shaft 2. Pass one end of the four screws 7 through the shaft hole of the coupling 3 and then screw them into the bolt hole at the head of the gearbox shaft 2, and tighten them.

[0062] Step 2: Install the upper guard plate 4 below the coupling 3, so that the four screws 7 respectively pass through the long holes of the upper guard plate 4, and fix them with the sleeve 5 and the nut A6. At the same time, rotate the four nuts A6 to make the coupling 3 move slowly upward until the top end of the internal spline on the coupling 3 contacts the bottom end of the external spline on the gearbox shaft 2.

[0063] Step 3: Rotate the coupling 3 so that the internal spline of the coupling 3 just fits with the external spline of the gearbox shaft 2, as Figure 10 shown;

[0064] Continue to rotate the four nuts A6 to make the coupling 3 continue to move slowly upward until the mating surface of the coupling 3 contacts the mating surface of the gearbox shaft 2 and cannot move upward any further, then stop rotating the nut A6.

[0065] Step 4: Remove one of the screws 7, pass it through the round hole of the upper guard plate 4 and then reconnect it to the gearbox shaft 2, and then sequentially remove and replace one screw 7 at the diagonal of the above-mentioned screw 7 and the other two screws 7;

[0066] Step 5: Slip the lower guard plate 9 onto the bottom ends of the four screw rods 7, position it with nut B, then place the jack 8 in the circular groove of the lower guard plate 9. Rotate nut B to drive the lower guard plate 9 upward, simultaneously moving the jack 8 upward and engaging it in the circular groove of the upper guard plate 4, and tighten nut B.

[0067] Step 6: Heat the outer surface of the coupling 3 with a torch to cause it to expand thermally, increasing the clearance between the mating surface of the coupling 3 and the mating surface of the gearbox shaft 2, enabling the coupling 3 to continue moving upward.

[0068] Then pressurize the jack 8 to slowly drive the upper guard plate 4 and the coupling 3 to move upward synchronously.

[0069] Step 7: After the coupling 3 is properly installed on the gearbox shaft 2, keep the jack 8 stationary and remove the tooling after the coupling 3 has cooled.

Claims

1. A method for assembling a coupling of a nuclear power plant circulating pump gearbox, characterized in that: The gearbox shaft (2) and the coupling (3) are assembled using the assembling tool for the coupling of the nuclear power plant circulating pump gearbox. The assembling tool includes an upper guard plate (4), nut A (6), screw rod (7), jack (8), lower guard plate (9), and nut B; The upper guard plate (4) is of a circular plate structure. A circular groove is machined at the center position of its lower surface, and N through holes are equidistantly arranged along the circumferential direction outside the circular groove, where N≥3; The upper edge of the upper guard plate (4) is clamped in the stop of the coupling (3); The lower guard plate (9) is of a circular plate structure. A circular groove is machined at the center position of its upper surface, and N through holes are equidistantly machined along the circumferential direction outside the circular groove; The jack (8) is arranged between the circular groove of the upper guard plate (4) and the circular groove of the lower guard plate (9); There are N screw rods (7). One end extends out from the through hole of the upper guard plate (4), passes through the shaft hole of the coupling (3), and then is screwed into the bolt hole at the head of the gearbox shaft (2), and the other end passes through the through hole of the lower guard plate (9); A nut A (6) is arranged on the screw rod (7) below the upper guard plate (4) to fix the upper guard plate (4); A nut B is arranged on the screw rod (7) below the lower guard plate (9) to fix the lower guard plate (9) and thus support the jack (8). By jacking up the jack (8), the upper guard plate (4) moves slowly and smoothly upward; N long holes and N through holes are arranged at equal intervals along the circumferential direction and crosswise outside the circular groove on the lower surface of the upper guard plate (4); The assembling method includes the following steps: Step 1: Transport the coupling (3) directly below the gearbox shaft (2). Pass one end of the four screw rods (7) through the shaft hole of the coupling (3) and then screw them into the bolt holes at the head of the gearbox shaft (2), and tighten them; Step 2: Install the upper guard plate (4) below the coupling (3) so that the four screw rods (7) pass through the long holes of the upper guard plate (4) respectively, and fix them with four nuts A (6); Rotate the four nuts A (6) simultaneously so that the coupling (3) moves slowly upward until the top end of the internal spline on the coupling (3) contacts the bottom end of the external spline on the gearbox shaft (2); Step 3: Rotate the coupling (3) so that the internal spline of the coupling (3) just matches the external spline of the gearbox shaft (2); Continue to rotate the four nuts A (6) so that the coupling (3) continues to move slowly upward until the mating surface of the coupling (3) contacts the mating surface of the gearbox shaft (2) and cannot move upward any further, then stop rotating the nut A (6); Step 4: Remove one of the screw rods (7), pass it through the round hole of the upper guard plate (4) and then reconnect it to the gearbox shaft (2), and then sequentially remove and replace the remaining screw rods (7); Step 5: Slide the lower guard plate (9) onto the bottom ends of the four screw rods (7) and position it with the nut B. Then place the jack (8) in the circular groove of the lower guard plate (9). Rotate the nut B to drive the lower guard plate (9) to move upward, and at the same time move the jack (8) upward and clamp it in the circular groove of the upper guard plate (4), and tighten the nut B; Step 6: Heat the outer surface of the coupling (3) to make it expand thermally, widen the gap between the mating surface of the coupling (3) and the mating surface of the gearbox shaft (2), so that the coupling (3) can continue to move upward; Then pressurize the jack (8) to slowly drive the upper guard plate (4) and the coupling (3) to move upward synchronously; Step 7: After the coupling (3) and the gearbox shaft (2) are installed in place, keep the jack (8) stationary, and disassemble the tooling after the coupling (3) cools down.

2. A method for assembling a coupling of a nuclear power plant circulating pump gearbox as claimed in claim 1, characterized in that: N＝4。 3. A method for assembling a coupling of a nuclear power plant circulating pump gearbox as claimed in claim 1, characterized in that: A sleeve (5) is sleeved on the screw rod (7) between the upper guard plate (4) and the nut A (6) of the assembling tool to prevent damage to the lower surface of the upper guard plate (4) during the process of rotating the nut A (6), and at the same time extend the operating space to the lower part of the coupling (3) to facilitate rotating the nut A (6).

4. A method for assembling a coupling of a nuclear power plant circulating pump gearbox as claimed in claim 1, characterized in that: The screw rods (7) of the assembling tool are all through-thread bolts.

5. A method for assembling a coupling of a nuclear power plant circulating pump gearbox as claimed in claim 1, characterized in that: The size of the circular groove on the upper guard plate (4) of the assembling tool is the same as the size of the jacking part of the jack (8), and the size of the circular groove on the lower guard plate (9) is the same as the size of the base of the jack (8).

6. A method for assembling a coupling of a nuclear power plant circulating pump gearbox as claimed in claim 1, characterized in that: In step 4, after removing one of the screw rods (7), sequentially remove and replace one screw rod (7) at the diagonal of the above-mentioned screw rod (7) and the remaining two screw rods (7).

7. A method for assembling a coupling of a nuclear power plant circulating pump gearbox as claimed in claim 6, characterized in that: In step 6, use a blowtorch to heat the outer surface of the coupling (3).

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