High-speed high-pressure large-flow fuel centrifugal pump and disassembly and assembly method thereof

Abstract

The invention belongs to the technical field of centrifugal pumps, and particularly relates to a high-speed high-pressure large-flow fuel centrifugal pump and a dismounting and mounting method thereof.The designed fuel centrifugal pump is composed of an impeller with a shaft, a main shaft shell, a rolling rod bearing, a bearing outer ring lining, a bearing inner ring lining, a ball bearing, a pressing plate, a locking nut, a transmission rod, an inlet shell, a blanking cap, a circular check block and a sealing assembly; through the integrated design of the impeller and the impeller shaft, the impeller and the impeller shaft do not have a circumferential gap existing in a traditional structure in the circumferential direction, the problem of abrasion caused by circumferential micro motion in the working process of the impeller is structurally eliminated, and the problems that the reliability of the high-speed high-pressure large-flow fuel centrifugal pump is limited, and the service life is not long can be effectively solved; meanwhile, in consideration of practical engineering application characteristics, the invention further provides a disassembly and assembly method of the fuel pump with the impeller and the impeller shaft integrally designed, disassembly and assembly of the fuel pump can be achieved through a simple tool, the disassembly and assembly process is simple and convenient, component parts are not damaged, and wide application prospects are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of centrifugal pumps, and in particular to the design of a fuel centrifugal pump for an aviation engine fuel control system. The designed high-speed, high-pressure, and high-flow fuel centrifugal pump is used in an engine fuel system, and its function is to provide the engine with fuel with a certain pressure and flow that meets working needs. Background Art

[0002] At present, the fuel centrifugal pump used in aviation turbofan (jet) engines has high speed (up to 30,000r / min), high outlet fuel pressure (up to 15MPa), large flow (up to 50,000kg / h), and a driving power of up to about 300kw. Compared with the performance of the previously used fuel centrifugal pump, in addition to the same speed (about 30,000r / min), the outlet fuel pressure increased from about 7.5MPa to about 15MPa, and the flow increased from about 30,000kg / h to about 50,000kg / h, and the driving power of the fuel centrifugal pump increased by more than three times. Under such a large load, stringent requirements are placed on the strength of the component structure of the centrifugal pump. At the same time, considering the actual assembly difficulty and processing difficulty, the component parts are generally manufactured in split parts and finally assembled into an integral structure; the impeller and impeller shaft of the booster component of the traditional fuel centrifugal pump are generally connected by conventional reliable splines, flat keys, etc. For high-speed, high-pressure, and large-flow fuel centrifugal pumps, actual applications have found that the service life of these traditional centrifugal pump design structures is difficult to meet the specified requirements. Summary of the invention

[0003] Purpose of the invention: The present invention proposes a high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated impeller and impeller shaft design. The impeller and impeller shaft are designed as an integrated whole, which completely avoids the circumferential micro-motion between the impeller and the impeller shaft during operation, and greatly improves the reliability and life of the fuel centrifugal pump.

[0004] Technical solution: On the one hand, the present invention proposes a high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated design of an impeller and an impeller shaft, which is composed of an impeller with an axis, a main shaft housing, a roller bearing, a bearing outer ring bushing, a bearing inner ring bushing, a ball bearing, a pressure plate, a locking nut, a transmission rod, an inlet housing, a plug cover, a circular stopper, and a sealing assembly;

[0005] The shaft impeller comprises a front impeller and a transmission shaft section, which are integrally formed; the transmission shaft section is designed as a step-shaped structure; the left end of the main shaft housing is fixed to the inlet housing, and the space between the two is used as the impeller installation space of the shaft impeller; the main shaft housing is provided with a first installation cavity for installing a larger diameter section of the transmission shaft, and a second installation cavity for assembling a roller bearing, a bearing outer ring bushing, a bearing inner ring bushing, and a ball bearing;

[0006] The transmission shaft section of the shaft impeller is installed into the main shaft housing through the hole on the main shaft housing, and is supported by roller bearings and ball bearings in the main shaft housing. The inner and outer rings of the roller bearings and the ball bearings are supported by bearing inner ring bushings and bearing outer ring bushings respectively. The outer ring of the ball bearing is pressed by a pressure plate and screws, and the inner ring of the ball bearing is locked by a locking nut. The left end face of the roller bearing abuts against the step end face of the transmission shaft section of the shaft impeller to limit the radial and axial position of the shaft impeller; the circular stopper is installed on the left side of the roller bearing; the cross-section of the circular stopper is an L-shaped ring structure The root of the outer ring of the circular stopper is against the outer ring of the roller bearing, and the left side of the roller bearing is axially restricted; the diameter of the inner ring of the circular stopper is slightly larger than the outer diameter of the shaft section of the shaft impeller, and slightly smaller than the outer diameter of the inner ring of the roller bearing, and a certain gap is left between the inner ring of the circular stopper and the side of the inner ring of the roller bearing; the thickness D of the outer ring of the circular stopper also satisfies: D+L1=L2-H2; wherein L1 is the length of the first installation cavity of the spindle housing; L2 is the length of the larger diameter section of the transmission shaft section of the shaft impeller 1, and H2 is the gap between the shaft impeller 1 and the end of the spindle housing 2 when the shaft impeller 1 is working;

[0007] The main shaft housing and the transmission shaft journal of the shaft impeller are equipped with sealing components; the left end of the shaft impeller is sealed with a plugging cover and a sealing ring to ensure that the imported fuel will not flow to the right end through the inner hole of the shaft impeller; the right end of the shaft impeller is equipped with a transmission rod, and the external power drives the shaft impeller to rotate through the transmission rod; when the high-speed, high-pressure, and large-flow fuel centrifugal pump is working, the shaft impeller is driven to rotate through the transmission rod, and the fuel enters from the "RYJ" port, and flows out from the "RYC" port after being pressurized by the shaft impeller. In this process, part of the pressurized fuel flows back through the gap "H1" "RYJ" port, and the other way flows to the "DP" chamber through "H2" and the gap "X" between ΦB1 and ΦC1. The "DP" chamber communicates with the "RYJ" port through the "HYG" flow channel to ensure that the pressure of the "DP" chamber is close to that of the "RYJ" port, ensuring that the sealing component works in a lower fuel pressure environment; the lubricating oil enters the main shaft housing from the "HYJ" port, passes through the internal flow channel, and then passes through the two nozzles "PZ1" and "PZ2" to cool and lubricate the roller bearing and ball bearing respectively. The lubricated oil flows out of the main shaft housing through the "HYC" port.

[0008] Furthermore, the first installation cavity of the main shaft housing is a stepped structure, with a slightly smaller diameter on the side close to the impeller, and a sealing assembly is arranged in the larger diameter installation cavity to divide the two sides of the installation cavity.

[0009] Furthermore, the sealing assembly includes a shaft seal and a spacer sleeve, and the spacer sleeve is installed between the two shaft seals.

[0010] Furthermore, the two shaft seals are both ring-mounted structures with a U-shaped cross-section. When installed, the U-shaped openings of the two shaft seals are arranged in opposite directions along the axial direction.

[0011] Furthermore, after the inlet housing is equipped with an O-ring, it is installed on the left end of the main shaft housing through screws, so that the impeller part of the shaft impeller works in the cavity formed by the inlet housing and the main shaft housing.

[0012] Furthermore, the shaft impeller is a hollow structure with variable diameter, and the impeller end is sealed with a plug cover; the diameter of the transmission shaft section of the shaft impeller increases step by step from the impeller end to the tail end.

[0013] Furthermore, the inner cavity of the transmission shaft with the shaft impeller is meshed with the transmission rod through gears to achieve transmission.

[0014] The present invention also proposes a method for disassembling a high-speed, high-pressure, and high-flow centrifugal fuel pump as designed above, wherein the method uses a set of disassembly and assembly tools, wherein the disassembly and assembly tools include a disassembly sleeve and a sleeve shaft, wherein the disassembly sleeve is a circular elastic structural member with a flange and a conical thin wall designed according to the inner hole of a circular stopper, and a plurality of grooves distributed along the axial direction are processed on the cone, and the flange size can be reduced after applying force from the circumferential direction; the sleeve shaft is a stepped shaft, the front end of which is a conical guide head with a larger diameter, and the rear end is a shaft section;

[0015] The fuel centrifugal pump disassembly process includes the following steps:

[0016] Step 1: Remove the inlet housing, screws, pressure plate, locking nut and transmission rod;

[0017] Step 2: Take the left end face of the main shaft housing as the bearing surface, apply force F1, and at the same time apply another force F2 to press the right end face of the impeller with shaft to the left; in this process, the left end face of the inner ring of the roller bearing fits with the right end face of the circular stopper until the inner ring of the roller bearing is pressed out from the shaft journal of the impeller with shaft;

[0018] Step 3: With the circular stopper as support, disassemble the roller bearing, the outer ring bushing of the bearing, the inner ring bushing of the bearing and the ball bearing; in this process, use the disassembly and assembly tool to insert the disassembly sleeve into the installation cavity of the spindle housing along one end of the inlet housing, apply circumferential force to the disassembly sleeve, reduce the flange size to the size that can accommodate the inner ring of the roller bearing, and when the right end face of the flange moves to the left and passes over the left end face of the circular stopper, release the circumferential force acting on the circular stopper, and the flange size is restored; at this time, the right end face of the flange is against the left end face of the circular stopper; insert the sleeve shaft into the inner hole of the disassembly sleeve; continue to apply force F3 to the left end of the sleeve shaft, and at the same time, apply force F4 to the right end of the spindle housing to remove the circular stopper, the roller bearing, the outer ring bushing of the bearing, the inner ring bushing of the bearing and the ball bearing from the spindle housing;

[0019] Step 4: Use the same method and disassembly tool of appropriate size to remove the shaft seal; complete the disassembly and assembly of the entire fuel pump.

[0020] Beneficial technical effects: After long-term research and demonstration, it was found that no matter the traditional fuel centrifugal pump impeller and impeller shaft are splined or keyed, there is inevitably a gap between the impeller and the impeller shaft in the circumferential direction, which makes the instantaneous speed between the impeller and the impeller shaft have a large deviation when the fuel centrifugal pump starts and stops quickly, and circumferential micro-motion will occur between the impeller and the impeller shaft; resulting in friction and wear between the right end face of the impeller installed on the outer circle of the impeller shaft ΦA connected by two keys and tightened with nuts and the adjusting gasket (or friction and wear between the left end face of the impeller and the nut). When the wear amount is greater than the assembly clearance required by the product, the high-speed rotating impeller will easily collide with the casing, causing the fuel centrifugal pump to fail and seriously shorten its service life.

[0021] The present invention adopts an integrated design of the impeller and the impeller shaft, so that there is no circumferential gap between the impeller and the impeller shaft in the circumferential direction that exists in the traditional structure, and the wear problem caused by the circumferential micro-motion of the impeller during operation is eliminated from the structural point of view, which can effectively solve the problems that restrict the reliability and service life of high-speed, high-pressure and large-flow fuel centrifugal pumps; at the same time, considering the characteristics of actual engineering applications, the present invention also proposes a disassembly and assembly method of the fuel pump with an integrated design of the impeller and the impeller shaft, and the fuel pump can be disassembled and assembled by using simple tooling, and the disassembly and assembly process is simple without damaging the components, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. It is obvious that the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A structural diagram of a high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated impeller and impeller shaft according to the present invention;

[0024] Figure 2 The diagram is a schematic diagram of the connection between the impeller (YL) and the impeller shaft (YLZ) of a conventional fuel centrifugal pump through a flat key (PJ);

[0025] Figure 3 This is a structural diagram of the spindle housing 2;

[0026] Figure 4 It is a schematic diagram of the impeller structure with shaft;

[0027] Figure 5 It is a schematic diagram of the structure of the inlet housing 15;

[0028] Figure 6 It is a schematic structural diagram of the transmission rod 11;

[0029] Figure 7It is a schematic diagram of the structure of the plugging cover 16;

[0030] Figure 8 It is a schematic diagram of the structure of the locking nut 10;

[0031] Fig. 9 It is a schematic diagram of the structure of the bearing inner ring bushing 6;

[0032] Fig.10 It is a schematic diagram of the structure of the bearing outer ring bushing 5;

[0033] Fig.11 The disassembly process of a high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated impeller and impeller shaft (removing the inlet housing 15, screws 9, pressure plate 8, locking nut 10, and transmission rod 11);

[0034] Fig.12 The disassembly process of a high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated impeller and impeller shaft (disassembly of the impeller with shaft 1);

[0035] Fig.13 A special tool for removing the circular stopper 18, the roller bearing 4, the bearing outer ring bushing 5, the bearing inner ring bushing 6 and the ball bearing 7;

[0036] Fig.14 Schematic diagram of disassembling the circular stopper 18, the roller bearing 4, the bearing outer ring bushing 5, the bearing inner ring bushing 6 and the ball bearing 7;

[0037] Fig.15 Diagram for calculating the torsional stress of the shaft neck before the integrated design of the impeller and impeller shaft;

[0038] Fig.16 Diagram for calculating journal torsional stress after the integrated design of impeller and impeller shaft. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] The features and illustrative embodiments of various aspects of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is by no means limited to any specific settings and methods proposed below, but covers any improvements, replacements and modifications of structures, methods, devices without departing from the spirit of the present invention. In the accompanying drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity in the present invention.

[0041] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] The structure of the high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated impeller and impeller shaft is as follows: Figure 1 It is composed of an impeller with shaft 1, a main shaft housing 2, a shaft seal 3, a roller bearing 4, a bearing outer ring bushing 5, a bearing inner ring bushing 6, a ball bearing 7, a pressure plate 8, a screw 9, a locking nut 10, a transmission rod 11, a spacer 12, an O-ring 13, a screw 14, an inlet housing 15, a plug cover 16, an O-ring 17, and a circular stopper 18.

[0043] exist Figure 1In the embodiment, the ΦC1 section of the shaft impeller 1 is installed into the spindle housing 2 through the ΦB1 hole on the spindle housing 2, and is supported by a roller bearing 4 and a ball bearing 7 in the spindle housing 2. The inner and outer rings of the roller bearing 4 and the ball bearing 7 are supported by a bearing inner ring bushing 6 and a bearing outer ring bushing 5 respectively. The outer ring of the ball bearing 7 is pressed by a pressure plate 8 and a screw 9, and the inner ring of the ball bearing 7 is locked by a locking nut 10, so as to limit the radial and axial positions of the shaft impeller 1. At the same time, in order to facilitate disassembly and assembly, a circular stopper 18 is also designed and installed on the left side of the roller bearing 4. The cross section of the circular stopper 18 is an L-shaped ring structure, and the root of the outer ring of the circular stopper 18 is against the outer ring of the roller bearing 4, so as to axially limit the left side of the roller bearing 4. The inner ring diameter of the circular stopper 18 is slightly larger than the outer diameter of the shaft section of the shaft impeller, and slightly smaller than the outer diameter of the inner ring of the roller bearing 4, and a certain gap is left between the inner ring of the circular stopper and the side of the inner ring of the roller bearing. Two shaft seals 3 are installed at the ΦB2 hole of the main shaft housing 2 and the ΦC1 journal of the shaft impeller 1, and a spacer 12 is installed between the shaft seals; the left end of the shaft impeller 1 is blocked with a plug cover 16 and an O-ring 17 to ensure that the imported fuel will not flow to the right end through the inner hole of the shaft impeller 1; the right end of the shaft impeller 1 is equipped with a transmission rod 11, and the external power drives the shaft impeller 1 to rotate through the transmission rod 11; after the inlet housing 15 is equipped with an O-ring 13, it is installed on the left end of the main shaft housing 2 by means of screws 14, so that the impeller part of the shaft impeller 1 works in the cavity formed by the inlet housing 15 and the main shaft housing 2; in order to facilitate assembly, a stepped groove is opened at the right end of the main shaft housing 2 for installing a fixed pressure plate 8.

[0044] In the design of the present invention, in order to achieve accurate installation of the shaft impeller 1 in the installation cavity of the main shaft housing 2, on the one hand, the transmission shaft section of the shaft impeller 1 is designed as a stepped structure, including two diameter sections, and the diameter of the section close to the impeller is slightly larger; at the same time, a circular stopper 18 is also designed, and the circular stopper 18 is installed at the root of the larger diameter installation cavity of the main shaft housing 2; the design of the circular stopper 18 can not only effectively ensure the gap between the front end impeller of the shaft impeller 1 and the housing during installation, but also facilitate the disassembly and assembly of the fuel pump in the later stage; the circular stopper 18 is designed as an annular structure with an L-shaped cross section, the outer ring of the circular stopper 18 is consistent with the outer ring diameter of the roller bearing 4, and the inner ring diameter of the circular stopper 18 is slightly larger than the outer diameter of the larger diameter section of the transmission shaft section of the shaft impeller 1, and is slightly smaller than the outer diameter of the inner ring of the roller bearing 4; at the same time, the outer ring thickness D of the circular stopper 18 (i.e., the thickest position of the L-shaped cross section) satisfies: D+L1=L2-H2; wherein L1 is the first installation of the main shaft housing 2 The length of the cavity; L2 is the length of the larger diameter section of the transmission shaft section of the shaft impeller 1, and H2 is the gap between the shaft impeller 1 and the end of the main shaft housing 2 when the shaft impeller 1 is working; such a design can ensure that when the shaft impeller 1 is installed, the shaft impeller 1 is first inserted into the installation cavity of the main shaft housing 2 to the limited position, at which time the right end face of the shaft impeller 1 is against the left end face of the installation cavity of the main shaft housing 2; then the roller bearing 4, the bearing outer ring bushing 5, and the bearing inner ring bushing are successively installed along the installation cavity of the main shaft housing 2 6. Ball bearing 7. Press plate 8. When the outer ring of roller bearing 4 abuts against the outer ring of circular stopper 18, the outer ring of roller bearing 4 is pressed to the limit position, and the inner ring of roller bearing 4 abuts against the step end face of the drive shaft of shaft impeller 1. During the pressing process, roller bearing 4 pushes shaft impeller 1 to move leftward by H2, so that the position of shaft impeller 1 in the installation cavity is guaranteed, that is, the gap between the front end of impeller and inlet housing 15 is H1; the gap between the rear end of impeller and the end of main shaft housing 2 is H2.

[0045] When the high-speed, high-pressure, and high-flow fuel centrifugal pump is working, the transmission rod 11 drives the shaft impeller 1 to rotate, the fuel enters from the "RYJ" port, and flows out from the "RYC" port after being pressurized by the shaft impeller 1. In this process, a part of the pressurized fuel flows back to the "RYJ" port through the gap "H1", and the other part flows to the "DP" cavity through "H2" and the gap "X" between ΦB1 and ΦC1. The "DP" cavity communicates with the "RYJ" port through the "HYG" flow channel to ensure that the pressure of the "DP" cavity is close to that of the "RYJ" port, ensuring that the shaft seal 3 works in a lower fuel pressure environment; the lubricating oil enters the main shaft housing 2 from the "HYJ" port, and after passing through the internal flow channel, it cools and lubricates the roller bearing 4 and the ball bearing 7 through the two nozzles "PZ1" and "PZ2" respectively, and the lubricated lubricating oil flows out of the main shaft housing 2 through the "HYC" port.

[0046] The integrated design of the impeller and the impeller shaft not only eliminates the wear problem caused by the circumferential micro-motion of the impeller during operation, but also significantly increases the diameter of the shaft neck. On the other hand, there is no need to consider the lubrication between the impeller and the impeller shaft and other sealing designs required for lubrication. Figure 2 In the impeller (YL) and the impeller shaft (YLZ) are connected by a flat key (PJ). At this time, the journal diameter (ΦA) is Φ20mm, which is the weakest part of the impeller shaft (YLZ); after the integrated design, the journal size of the original structure ΦA is increased from Φ20 to Φ37. After deducting the influence of the empty knife groove size ΦC2 (Φ17), the torsion resistance of the shaft in this part is increased by 6 times. The service life and reliability of the product are greatly improved; in traditional centrifugal pumps, due to the limitations of assembly and disassembly, the impeller and the impeller shaft are connected by a flat key (PJ) or spline. This connection method needs to consider the lubrication of the connection and the heat generated during the mutual engagement movement; in the design, the oil in the DP cavity is used, which not only plays a lubricating role, but also can take away the heat generated during the working process; such a design also brings about the problem of sealing design, especially the connection cavity between the impeller shaft and the transmission rod cannot be made into a complete cavity form, which is difficult to achieve the weight reduction characteristics to a certain extent.

[0047] The integrated design of impeller and impeller shaft is a relatively conventional design form. Although it significantly improves the life and reliability of high-speed, high-pressure, and high-flow fuel centrifugal pumps, the main reason for the actual application of existing projects in the industry is that the integrated design puts forward higher requirements for assembly. For example, how to effectively ensure the spatial position of the impeller in the installation cavity, that is, the gap between the front end of the impeller and the inlet housing is H1, and the gap between the rear end of the impeller and the end of the main shaft housing 2 is H2. If the two gaps are not well controlled, it will greatly affect the service life of the product; at the same time, it also brings some difficulties to disassembling the product during later maintenance, especially the difficulty of disassembly, which is particularly obvious for products such as high-speed, high-pressure, and high-flow fuel centrifugal pumps. This is also an important reason why there are few corresponding products in the industry. Figure 1 As shown, when disassembling, it is necessary to first remove the inlet housing 15 and the locking nut 10, and then press the shaft impeller 1 from right to left. During this process, due to the design of a certain assembly interference between the inner ring of the roller bearing and the shaft neck, the inner ring of the roller bearing 4 will move to the left with the shaft impeller 1, first crushing the shaft seal 3 until the inner ring of the roller bearing 4 abuts against the right end face of the ΦB1 hole on the main shaft housing 2, and the inner ring of the roller bearing 4 can be removed from the shaft impeller 1. Each disassembly will damage the shaft seal 3. After removing the shaft impeller 1, other parts and ball bearings 7 are also difficult to disassemble.

[0048] The present invention proposes a high-speed, high-pressure, and high-flow fuel centrifugal pump with an integrated design of an impeller and an impeller shaft, and also fully considers the assembly and disassembly problems. In the specific implementation process of the present invention, the solution to the disassembly problem is:

[0049] Step 1: Remove the inlet housing 15, screws 9, pressure plate 8, locking nut 10 and transmission rod 11. Fig.11 .

[0050] Step 2: Use the left end face of the main shaft housing 2 as the bearing surface, apply force F, and at the same time use force F to press the right end face of the belt shaft impeller 1 to the left. In this process, the left end face of the inner ring of the roller bearing 4 fits with the right end face of the circular stopper 18 ( Fig.12 -a), until the inner ring of the roller bearing 4 is pressed out from the shaft journal of the impeller 1 with shaft ( Fig.12 -b), of course, in actual implementation, the magnitude of the force applied on both sides can be determined according to the specific situation.

[0051] Step 3: With the circular stopper 18 as support, remove the roller bearing 4, the outer ring bushing 5, the inner ring bushing 6 and the ball bearing 7. In this process, a set of special tooling (TZGZ) is needed, which consists of a special sleeve (TZGZ-T) and a special sleeve shaft (TZGZ-Z), such as Fig.13 Among them, TZGZ-T is a flanged, conical thin-walled elastic part designed according to the inner hole of the circular stopper 18. Several grooves distributed along the axial direction are processed on the cone, and the flange size can be reduced after applying force from the circumferential direction; TZGZ-Z is stepped, and its function is to insert the outer circle of the cone end into the inner hole of the left end of the special sleeve, so that the flange on the special sleeve will not shrink in size during the force process, thus realizing the disassembly function.

[0052] For disassembly methods, see Fig.14 The specific process is as follows: apply circumferential force to the special sleeve (TZGZ-T) to reduce the flange size to a size that can fit into the inner ring of the roller bearing 4; when the right end face of the flange moves to the left and passes over the left end face of the circular stopper 18, release the circumferential force acting on the circular stopper 18, the flange size is restored, and the right end face of the flange is pressed against the left end face of the circular stopper 18; insert the special sleeve shaft (TZGZ-Z) into the inner hole of the special sleeve (TZGZ-T); press Fig.15 Apply force F3 to the left end of the sleeve shaft (TZGZ-Z) and apply force F4 to the right end of the spindle housing 2 to remove the circular stopper 18, roller bearing 4, bearing outer ring bushing 5, bearing inner ring bushing 6 and ball bearing 7 from the spindle housing 2.

[0053] Step 4: Use the same method and a similar tool of appropriate size to remove the shaft seal 3.

[0054] In order to ensure that the fuel pump components are not damaged during the disassembly and assembly process, the fuel centrifugal pump disassembly process is carried out on the same horizontal platform, and the coaxiality needs to be ensured during the disassembly and assembly process.

[0055] Example: Take a high-speed, high-pressure, high-flow fuel centrifugal pump as an example, with a speed of 30,000 r / min, an inlet fuel pressure of 0.5 MPa, an outlet fuel pressure of 15 MPa, and a maximum flow of 50,000 kg / h. The journal size of the ΦA part before the impeller and the impeller shaft are not integrated is Φ20; after the impeller and the impeller shaft are integrated, the journal size increases to Φ37 (the empty knife groove size is Φ17). The beneficial effect of the improvement is evaluated by calculating the torsional stress at the journal before and after the improvement.

[0056] Calculate the power of the impeller:

[0057] In the formula: P is the power of the impeller (W), μ is the hydraulic efficiency of the high-speed, high-pressure and large-flow fuel centrifugal pump, which is taken as 0.85 here.

[0058] Calculate the torque on the impeller journal:

[0059]

[0060] In the formula: T is the torque borne by the impeller journal (Nm), μ is the hydraulic efficiency of the high-speed, high-pressure and large-flow fuel centrifugal pump, which is taken as 0.85 here.

[0061] Calculate the torsional stress τ on the impeller journal:

[0062] Before integrated design:

[0063] like Fig.15 As shown in the figure, assuming that the torsional stress on the journal surface is τ1, the stress distribution on the journal cross section is:

[0064] In the formula: R----journal radius (m), r----radius of any point on the journal section (m), τ----stress distribution expression of the journal cross section.

[0065] Calculated τ1 = 63.7 (MPa)

[0066] After adopting the integrated design of the present invention:

[0067] like Fig.16 As shown, assuming that the torsional stress on the inner surface of the journal is τ2 and the torsional stress on the outer surface is τ3, the stress distribution on the cross section of the journal is: τ=100rτ3-100rτ2+1.85τ2-0.85τ3. According to the condition that the straight line passes through the origin of the coordinate system, when r=0, τ=0, and τ2=0.46τ3, thus τ=54rτ3.

[0068]

[0069] In the formula: r is the radius of any point on the journal section (m), τ is the stress distribution expression of the journal cross section.

[0070] Calculated τ3 = 10.53 (MPa)

[0071] The calculation results show that after the integrated design of the impeller and the impeller shaft, the torsional stress at the journal is reduced by 83.46% under the same working conditions. The wear caused by the circumferential micro-motion of the impeller and the impeller shaft during operation is avoided through the structural integration design, and the bearing capacity of the journal and the reliability of the fuel pump are improved. It can be seen that through the integrated design of the impeller and the impeller shaft, there is no circumferential gap between the impeller and the impeller shaft in the circumferential direction that exists in the traditional structure, and the wear problem caused by the circumferential micro-motion of the impeller during operation is eliminated from the structure, which can effectively solve the problem of restricting the reliability and service life of high-speed, high-pressure and large-flow fuel centrifugal pumps; combined with the disassembly and assembly method of the specific design of the present invention, it has a great prospect for engineering application.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A high-speed, high-pressure, high-flow fuel centrifugal pump, characterized in that: It consists of an impeller with shaft, a main shaft housing, a roller bearing, a bearing outer ring bushing, a bearing inner ring bushing, a ball bearing, a pressure plate, a locking nut, a transmission rod, an inlet housing, a plug cover, a circular stopper, and a sealing assembly; The shaft impeller comprises a front impeller and a transmission shaft section, which are integrally formed; the transmission shaft section is designed as a step-shaped structure; the left end of the main shaft housing is fixed to the inlet housing, and the space between the two is used as the impeller installation cavity of the shaft impeller; the main shaft housing is provided with a first installation cavity for installing a larger diameter section of the transmission shaft, and a second installation cavity for assembling a roller bearing, a bearing outer ring bushing, a bearing inner ring bushing, and a ball bearing; The transmission shaft section of the shaft impeller is installed into the main shaft housing through the hole on the main shaft housing, and is supported by roller bearings and ball bearings in the main shaft housing. The inner and outer rings of the roller bearings and the ball bearings are supported by bearing inner ring bushings and bearing outer ring bushings respectively. The outer ring of the ball bearing is pressed by a pressure plate and screws, and the inner ring of the ball bearing is locked by a locking nut. The left end face of the roller bearing abuts against the step end face of the transmission shaft section of the shaft impeller to limit the radial and axial position of the shaft impeller; the circular stopper is installed on the left side of the roller bearing; the cross-section of the circular stopper is an L-shaped ring structure. The root of the outer ring of the circular stopper is against the outer ring of the roller bearing, and the left side of the roller bearing is axially restricted; the diameter of the inner ring of the circular stopper is slightly larger than the outer diameter of the shaft section of the shaft impeller, and slightly smaller than the outer diameter of the inner ring of the roller bearing, and a certain gap is left between the inner ring of the circular stopper and the side of the inner ring of the roller bearing; the thickness D of the outer ring of the circular stopper also satisfies: D+L1=L2-H2; wherein L1 is the length of the first installation cavity of the spindle housing; L2 is the length of the larger diameter section of the shaft section of the shaft impeller; and H2 is the gap between the shaft impeller 1 and the end of the spindle housing when the shaft impeller 1 is working; The main shaft housing and the drive shaft journal of the shaft impeller are equipped with sealing components; the left end of the shaft impeller is sealed with a plugging cover and a sealing ring to ensure that the imported fuel will not flow to the right end through the inner hole of the shaft impeller; the right end of the shaft impeller is equipped with a transmission rod, and the external power drives the shaft impeller to rotate through the transmission rod; when the high-speed, high-pressure, and large-flow fuel centrifugal pump is working, the shaft impeller is driven to rotate through the transmission rod, and the fuel enters from the "RYJ" port, and flows out from the "RYC" port after being pressurized by the shaft impeller. In this process, part of the pressurized fuel flows back through the gap "H1" all the way. The fuel oil flows through the "RYJ" port, and the other way flows through the gap "H2" and the gap "X" between ΦB1 and ΦC1 to the "DP" cavity. The "DP" cavity communicates with the "RYJ" port through the "HYG" flow channel to ensure that the pressure of the "DP" cavity is close to that of the "RYJ" port, and ensure that the sealing component works in a lower fuel pressure environment; the lubricating oil enters the spindle housing from the "HYJ" port, passes through the internal flow channel, and cools and lubricates the roller bearing and the ball bearing through the two nozzles "PZ1" and "PZ2" respectively. The lubricated oil flows out of the spindle housing through the "HYC" port.

2. A high-speed, high-pressure, high-flow fuel centrifugal pump as claimed in claim 1, characterized in that: The first installation cavity of the main shaft housing is a stepped structure, with a slightly smaller diameter on the side close to the impeller. A sealing assembly is arranged in the larger diameter installation cavity to divide the two sides of the installation cavity.

3. A high-speed, high-pressure, high-flow fuel centrifugal pump as claimed in claim 2, characterized in that: The sealing assembly comprises a shaft seal and a spacer sleeve, wherein the spacer sleeve is arranged between two shaft seals.

4. A high-speed, high-pressure, high-flow fuel centrifugal pump as claimed in claim 3, characterized in that: The two shaft seals are both ring-mounted structures with U-shaped cross-sections. When installed, the U-shaped openings of the two shaft seals are arranged in opposite directions along the axial direction.

5. A high-speed, high-pressure, high-flow fuel centrifugal pump as claimed in claim 1, characterized in that: After the inlet housing is equipped with an O-ring, it is installed on the left end of the main shaft housing through screws, so that the impeller part of the shaft impeller works in the cavity formed by the inlet housing and the main shaft housing.

6. A high-speed, high-pressure, high-flow fuel centrifugal pump as claimed in claim 1, characterized in that: A stepped groove is provided at the right end of the spindle housing for installing a fixed pressure plate.

7. A high-speed, high-pressure, high-flow centrifugal fuel pump as claimed in claim 5, characterized in that: The shaft impeller is a hollow structure with variable diameter, and the impeller end is sealed with a plug cover; the diameter of the transmission shaft section of the shaft impeller increases step by step from the impeller end to the tail end.

8. A high-speed, high-pressure, high-flow centrifugal fuel pump as claimed in claim 7, characterized in that: The inner cavity of the transmission shaft with the shaft impeller is meshed with the transmission rod through gears to realize transmission.

9. The method for disassembling a high-speed, high-pressure, and high-flow centrifugal fuel pump according to any one of claims 1 to 8, characterized in that: The disassembly method adopts a set of disassembly tools, which are composed of a disassembly sleeve and a sleeve shaft, wherein the disassembly sleeve is a circular elastic structural part with a flange and a conical thin wall designed according to the inner hole of the circular stopper, and a plurality of grooves distributed along the axial direction are processed on the cone, and the flange size can be reduced after applying force from the circumferential direction; the sleeve shaft is a stepped shaft, the front end of which is a conical guide head with a larger diameter, and the rear end is a shaft section; The fuel centrifugal pump disassembly process includes the following steps: Step 1: Remove the inlet housing, screws, pressure plate, locking nut and transmission rod; Step 2: Take the left end face of the main shaft housing as the bearing surface, apply force F1, and at the same time apply another force F2 to press the right end face of the impeller with shaft to the left; in this process, the left end face of the inner ring of the roller bearing fits with the right end face of the circular stopper until the inner ring of the roller bearing is pressed out from the shaft journal of the impeller with shaft; Step 3: With the circular stopper as support, disassemble the roller bearing, the outer ring bushing of the bearing, the inner ring bushing of the bearing and the ball bearing; in this process, use the disassembly and assembly tool to insert the disassembly sleeve into the installation cavity of the spindle housing along one end of the inlet housing, apply circumferential force to the disassembly sleeve, reduce the flange size to the size that can accommodate the inner ring of the roller bearing, and when the right end face of the flange moves to the left and passes over the left end face of the circular stopper, release the circumferential force acting on the circular stopper, and the flange size is restored; at this time, the right end face of the flange is against the left end face of the circular stopper; insert the sleeve shaft into the inner hole of the disassembly sleeve; continue to apply force F3 to the left end of the sleeve shaft, and at the same time, apply force F4 to the right end of the spindle housing to remove the circular stopper, the roller bearing, the outer ring bushing of the bearing, the inner ring bushing of the bearing and the ball bearing from the spindle housing; Step 4: Use the same method and disassembly tool of appropriate size to remove the shaft seal; complete the disassembly and assembly of the entire fuel pump.

10. The method for disassembling a high-speed, high-pressure, and high-flow centrifugal fuel pump as claimed in claim 9, characterized in that: The disassembly process of the fuel centrifugal pump is carried out on the same horizontal platform to ensure the coaxiality during the disassembly and assembly process.

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