Combined set for mounting rotor of aircraft starter and mounting method of rotor

Abstract

The invention discloses a combined set for aircraft starter rotor installation and a rotor installation method.The set comprises an inner cylinder, an outer cylinder, a fixing lock rod and a centering cylinder, the inner cylinder is a hollow cylinder with the two ends open, a circle of check ring protruding outwards is integrally formed at the bottom of the inner cylinder, and the outer cylinder is a hollow cylinder with the two ends open; a circle of groove is formed in the middle of the outer surface of the outer barrel, the fixing lock rod comprises a rod part and a locking head part, and the inner edge and the outer edge of the locking head part are matched with the groove of the outer barrel and the clamping groove of the diffuser shell respectively; the centering cylinder is a hollow cylinder with two open ends. The combined set not only can offset the spring force, but also can ensure that the rotor shaft and the two high-speed bearings are always kept in a vertical state when the rotor is mounted. The invention further discloses a mounting method of the aircraft starter rotor.

Description

Technical Field

[0001] This invention pertains to installation equipment and methods for aircraft components, specifically referring to a combination kit and method for installing an aircraft starter rotor. Background Technology

[0002] As the core component of the aircraft starting system, the aircraft starter operates in an environment characterized by high speed and high temperature, which places extremely stringent requirements on the performance and assembly precision of the rotor and high-speed bearings. The rotor, as a key component in the starter that rotates at high speed and maintains stability, directly determines the starter's operating state through its structural integrity and assembly quality. Furthermore, the starter's internal structure is intricate, with close interactions between components; any improper operation during assembly can lead to starter failure, necessitating disassembly, repair, or refurbishment.

[0003] In starter motor repair or overhaul, rotor assembly is a crucial step. The rotor shaft has an uppermost shaft end and a connecting part that connects to the shaft end. The diameter of the shaft end is smaller than the diameter of the connecting part. The connecting part is tightly fitted with the inner rings of the second and first high-speed bearings, which are distributed vertically within the bearing bores of the aircraft starter diffuser housing. Specifically, the upper connecting section of the connecting part corresponds to the inner ring of the upper second high-speed bearing, and the lower connecting section corresponds to the inner ring of the lower first high-speed bearing. The upper and lower connecting sections are the same size, while the intermediate connecting section between the upper and lower connecting sections is smaller than both. This intermediate connecting section is used for mating with the bushing.

[0004] Because the rotor and high-speed bearing are tightly fitted, pressure must be applied during assembly. Uneven pressure can easily cause scratches on the rotor shaft surface and damage to the bearing inner ring. Damaged rotors and related components are usually imported precision parts, which are very expensive. Replacing them will not only significantly increase maintenance costs but also extend the maintenance cycle, making it difficult to meet the timeliness requirements of aircraft maintenance.

[0005] Furthermore, the rotor inside the starter is fixed in bearing holes in the diffuser housing by two high-speed bearings. A pressure spring and bushing are also installed between the two high-speed bearings within the bearing holes. When installing the second high-speed bearing, the spring force must be overcome to smoothly insert the bearing into the bearing hole of the diffuser housing. When installing the rotor shaft, it is necessary to ensure that the positions of the two high-speed bearings do not shift, and that the rotor shaft remains perpendicular to the two high-speed bearings at all times. Conventional assembly methods cannot meet the dual requirements of "counteracting the spring force" and "maintaining perpendicular alignment," resulting in low assembly efficiency and a high rate of component damage.

[0006] Therefore, there is an urgent need for a special assembly kit to solve the above assembly problems and achieve non-destructive and rapid assembly of rotors and high-speed bearings. Summary of the Invention

[0007] One of the objectives of this invention is to provide a combined fixture for installing an aircraft starter rotor. This fixture not only counteracts the spring force but also ensures that the rotor shaft remains perpendicular to the two high-speed bearings during installation.

[0008] This objective of the present invention is achieved by the following technical solution: a combined kit for installing an aircraft starter rotor, characterized in that: the kit includes a fixing component and a guide component;

[0009] The main function of the fixing component is to counteract the spring force of the spring installed in the bearing hole of the aircraft starter diffuser housing and fix the position of the two high-speed bearings so that they do not move, thereby ensuring that the rotor shaft and the two high-speed bearings remain perpendicular to each other when the aircraft starter rotor is installed.

[0010] The fixing component includes:

[0011] Inner cylinder: The inner cylinder is a hollow cylinder with open ends. The inner diameter of the inner cylinder is equal to the inner ring diameter of the second high-speed bearing and the first high-speed bearing, which are distributed vertically in the bearing hole of the aircraft starter diffuser housing. A convex retaining ring is integrally formed at the bottom of the inner cylinder.

[0012] Outer cylinder: The outer cylinder is a hollow cylinder with open ends. The inner diameter of the outer cylinder is equal to the outer diameter of the inner cylinder. The lower end face of the outer cylinder abuts against the upper surface of the stop ring. A groove is formed in the middle of the outer surface of the outer cylinder. The height of the groove is such that when the outer cylinder and the inner cylinder are pressed down by the stop ring under the action of external force, so that the second high-speed bearing is fully inserted into the bearing hole of the diffuser housing, the groove is facing the bottom of the central cavity of the diffuser housing.

[0013] Fixed locking rod: The fixed locking rod includes a rod part and a locking head. The inner edge of the locking head is adapted to the groove of the outer cylinder. When the second high-speed bearing is fully inserted into the bearing hole of the diffuser housing, the inner edge of the locking head is inserted into the groove of the outer cylinder, and the outer edge abuts against the bottom of the central cavity of the diffuser housing, thus locking the inner and outer cylinders and the diffuser housing as a whole, thereby also fixing the second high-speed bearing and the first high-speed bearing.

[0014] Once the diffuser housing and inner and outer cylinders are locked together, a stable structure is formed, which can effectively counteract the spring force generated by the spring, fix the position of the two high-speed bearings, and prevent the two high-speed bearings from shifting during rotor assembly. Only when the positions of the two high-speed bearings are fixed can it be ensured that the rotor shaft and the two high-speed bearings remain perpendicular to each other when the rotor is installed, thus meeting the assembly requirements of the rotor shaft and achieving the expected assembly effect.

[0015] The main function of the guide is to guide the centering and positioning of the rotor shaft, ensuring that the rotor shaft and the two high-speed bearings are always in the same vertical plane, while avoiding the rotor shaft from rubbing against the inner ring and bushing of the bearing installed in the bearing hole.

[0016] The guide component is a centering cylinder, which is a hollow cylinder open at both ends. The lower part of the centering cylinder is chamfered. The outer diameter of the centering cylinder is equal to the inner ring diameter of the two high-speed bearings and the inner diameter of the inner cylinder. The rotor shaft has a shaft end located at the uppermost end and a connecting part connected to the shaft end for tight fit with the inner ring of the two high-speed bearings. The diameter of the shaft end is smaller than the diameter of the connecting part. The inner diameter of the centering cylinder is equal to the diameter of the shaft end of the rotor shaft. In use, the centering cylinder is fitted onto the shaft end of the rotor shaft.

[0017] In this invention, the fixing locking rod is Y-shaped as a whole, the rod part is a straight rod, and the locking head is U-shaped.

[0018] In a preferred embodiment of the present invention, the chamfer angle is 15°-30°.

[0019] In this invention, the inner wall of the centering cylinder is polished to reduce the frictional resistance when the rotor shaft end passes through the centering cylinder, thereby reducing the risk of damage to the shaft end.

[0020] In this invention, the length of the centering cylinder is greater than the distance between the two high-speed bearings, and the distance between the two high-speed bearings refers to the distance between the lower surface of the second high-speed bearing and the upper surface of the first high-speed bearing.

[0021] The second objective of this invention is to provide a method for installing an aircraft starter rotor.

[0022] This objective of the present invention is achieved through the following technical solution: a method for installing an aircraft starter rotor using the above-described combined kit, characterized in that the installation method includes the following steps:

[0023] (1) Preliminary preparation: Clean the bearing holes of the aircraft starter diffuser housing and the bushings, springs and first high-speed bearings already installed in the bearing holes to ensure that there are no impurities; check the size and surface condition of each component of the assembly kit to confirm that there are no deformation or scratches.

[0024] (2) Preparation for installation of the second high-speed bearing: Place the second high-speed bearing into the diffuser housing, align the inner ring of the second high-speed bearing with the bushing, align the outer ring with the spring, and align the second high-speed bearing with the bearing hole of the diffuser housing for installation.

[0025] (3) Installation of fixed components: With the end of the inner cylinder with the retaining ring facing down, put the outer cylinder on the inner cylinder, and then put the inner cylinder and the outer cylinder into the cavity at the top of the diffuser housing until the retaining ring at the bottom of the inner cylinder contacts the inner ring of the second high-speed bearing;

[0026] (4) Installation of the second high-speed bearing: Apply uniform axial pressure to the inner cylinder and slowly push the second high-speed bearing downward until the second high-speed bearing is fully inserted into the bearing hole of the diffuser housing. After the second high-speed bearing is installed in place, the central axis of the two high-speed bearings, the central axis of the bushing and the central axis of the bearing hole coincide. At this time, the groove of the outer cylinder is facing the bottom of the central cavity of the diffuser housing.

[0027] (5) Fixing component locking: After the second high-speed bearing is installed in place, insert the fixing locking rod. The locking head of the fixing locking rod is inserted into the groove of the outer cylinder and abuts against the bottom of the middle cavity of the diffuser housing, locking the inner and outer cylinders and the diffuser housing as a whole to counteract the spring force of the spring and lock the position of the two high-speed bearings.

[0028] (6) Liquid nitrogen cooling of the rotor: The rotor is placed in liquid nitrogen for cooling, and the rotor shaft diameter is reduced to be smaller than the inner ring diameter of the two high-speed bearings, so that it can pass through the inner ring of the two high-speed bearings.

[0029] (7) Guide component installation: After locking, the entire diffuser housing and fixing assembly are mounted on the rotor shaft of the starter rotor from top to bottom. The rotor shaft has a shaft end at the uppermost end and a connecting part connected to the shaft end for tight fit with the inner rings of the two high-speed bearings. The diameter of the shaft end is smaller than the diameter of the connecting part. A stepped surface is formed at the intersection of the shaft end and the connecting part. At this time, the inner ring of the first high-speed bearing located below touches the rotor shaft. Then, the chamfered end of the centering cylinder is placed into the inner cylinder. The centering cylinder passes downward through the second high-speed bearing, the bushing, and the first high-speed bearing before being mounted on the shaft end of the rotor shaft. After mounting, the lower end face of the centering cylinder contacts the stepped surface where the shaft end of the rotor shaft and the connecting part intersect. The top end of the centering cylinder extends upward into the inner cylinder.

[0030] (8) Rotor shaft installation: Pressure is applied to the inner cylinder by the press. The pressure is transmitted to the inner ring of the first high-speed bearing through the inner cylinder retaining ring, the inner ring of the second high-speed bearing, and the bushing. The rotor shaft passes through the inner ring of the first high-speed bearing, the bushing, and the inner ring of the second bearing in sequence from the bottom of the diffuser housing upwards until the connecting part of the rotor shaft is located in the inner ring of the two high-speed bearings, thus achieving the requirement of the rotor shaft being installed in place. The centering cylinder ensures that the three central axes of the rotor shaft, the centering cylinder axis, and the bearing hole axis are coincident.

[0031] (9) Finishing: After the rotor shaft is installed in place, since the rotor shaft and the inner rings of the two high-speed bearings are tightly fitted, when the diameter of the rotor shaft increases and returns to the size at room temperature after the liquid nitrogen cooling effect disappears, the inner rings of the two high-speed bearings tightly fit the connecting part of the rotor shaft, completing the conversion of the aircraft starter rotor. After that, the fixing lock rod, outer cylinder, inner cylinder and centering cylinder are removed.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] Non-destructive assembly: By fixing the components and guiding them, the rotor shaft and high-speed bearing are always kept in the same vertical plane, avoiding scratches and damage to parts during assembly and significantly reducing the cost of replacing parts.

[0034] High efficiency and convenience: The fixing component can counteract the spring force, and the bearing can be fixed without complicated operations. The assembly time is reduced by more than 50% compared with conventional methods, which meets the maintenance cycle requirements.

[0035] High versatility: The dimensions of the fixing components and guide parts can be flexibly adjusted according to the specifications of the high-speed bearings and diffuser housings of different starter models, making it suitable for the maintenance of starter models of various types.

[0036] High reliability: All components of the assembly kit are made of stainless steel, which can withstand the pressure and wear during the assembly process and has a long service life.

[0037] In summary, this invention effectively solves the technical problems of "difficulty in counteracting spring force" and "easy damage during assembly" in the assembly process of aircraft starter rotors, providing an efficient and reliable special tool for starter maintenance, and has significant practical value and prospects for promotion. Attached Figure Description

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 This is a schematic diagram of the outer cylinder in the combined sleeve of the present invention;

[0040] Figure 2 This is a schematic diagram of the inner cylinder in the combined sleeve of the present invention;

[0041] Figure 3 This is a schematic diagram of the structure of the fixing locking rod in the combined kit of the present invention;

[0042] Figure 4 This is a schematic diagram of the centering cylinder in the combined sleeve of the present invention;

[0043] Figure 5 This is a reference diagram showing the usage state of the combined kit of the present invention;

[0044] Figure 6 A schematic diagram of the structure of an aircraft starter diffuser housing;

[0045] Figure 7 A schematic diagram of the structure of an aircraft starter rotor shaft;

[0046] Reference numerals in the attached drawings: 1. Inner cylinder; 1a. Stop ring; 2. Outer cylinder; 2a. Groove; 3. Fixing locking rod; 3a. Rod part; 3b. Locking head; 4. Centering cylinder; 4a. Chamfer; 5. Diffuser housing; 5a. Central cavity circular hole; 6. Rotor shaft; 6a. Shaft end; 6b. Connecting part; 7. First high-speed bearing; 8. Second high-speed bearing; 9. Bushing; 10. Spring. Detailed Implementation

[0047] like Figures 1 to 7 The assembly kit shown is for mounting aircraft starter rotors and includes a fixing component and a guide.

[0048] The main function of the fixing component is to counteract the spring force of the spring 10 installed in the bearing hole of the aircraft starter diffuser housing 5, and to fix the position of the two high-speed bearings so that they do not move, thereby ensuring that the rotor shaft 6 and the two high-speed bearings remain perpendicular to each other when the aircraft starter rotor is installed.

[0049] In this embodiment, the fixing component includes:

[0050] Inner cylinder 1: Inner cylinder 1 is a hollow cylinder with open ends. The inner diameter of the inner cylinder 1 is equal to the inner ring diameter of the second high-speed bearing 8 and the first high-speed bearing 7, which are distributed vertically in the bearing hole of the aircraft starter diffuser housing 5. The bottom of the inner cylinder 1 has an integrally formed outwardly protruding stop ring 1a. When in use, the stop ring 1a of the inner cylinder 1 contacts the inner ring of the second high-speed bearing 8.

[0051] Outer cylinder 2: The outer cylinder 2 is a hollow cylinder with open ends. The inner diameter of the outer cylinder 2 is equal to the outer diameter of the inner cylinder 1. When in use, the outer cylinder 2 is fitted into the inner cylinder 1. The lower end face of the outer cylinder 2 abuts against the upper surface of the stop ring 1a. A groove 2a is opened in the middle of the outer surface of the outer cylinder 2. The height of the groove 2a is such that when the outer cylinder 2 and the inner cylinder 1 are pressed down by the stop ring 1a under the action of external force, so that the second high-speed bearing 8 is fully inserted into the bearing hole of the diffuser housing 5, the groove 2a is facing the bottom of the middle cavity circular hole 5a opened in the diffuser housing 5.

[0052] Fixed locking rod 3: The fixed locking rod 3 includes a rod part 3a and a locking head 3b. The fixed locking rod 3 is Y-shaped as a whole. The rod part 3a is a straight rod, and the locking head 3b is U-shaped. The inner edge of the locking head 3b is adapted to the groove 2a of the outer cylinder 2, and the outer edge abuts against the bottom of the central cavity circular hole 5a of the diffuser housing 5. When the second high-speed bearing 8 is fully inserted into the bearing hole of the diffuser housing 5, the inner edge of the locking head 3b is inserted into the groove 2a of the outer cylinder 2, and the outer edge abuts against the bottom of the central cavity circular hole 5a of the diffuser housing 5, thus locking the inner and outer cylinders 2 and the diffuser housing 5 as a whole, thereby fixing the second high-speed bearing 8 and the first high-speed bearing 7, preventing the two high-speed bearings from moving, and facilitating the subsequent installation of the aircraft starter rotor.

[0053] The outer cylinder 2 has a diameter smaller than the cavity size at the top of the diffuser housing 5, which facilitates the entry of the outer cylinder 2. After the fixing rod 3 is inserted into the groove 2a of the outer cylinder 2 and locked at the bottom of the central cavity circular hole 5a of the diffuser housing 5, the outer cylinder 2 and the inner cylinder 1 can be stably fixed inside the diffuser housing 5, providing a fixed foundation for the subsequent installation of the rotor.

[0054] After the diffuser housing 5 and the inner and outer cylinders 2 are locked together, a stable structure is formed, which can effectively counteract the spring force generated by the spring 10, fix the position of the two high-speed bearings, and prevent the two high-speed bearings from shifting during the assembly of the rotor. Only when the positions of the two high-speed bearings are fixed can it be ensured that the rotor shaft 6 and the two high-speed bearings remain perpendicular to each other when the rotor is installed, thus meeting the assembly requirements of the rotor shaft 6 and achieving the expected assembly effect.

[0055] During assembly, the outer cylinder 2 is fitted onto the inner cylinder 1, with the lower end face of the outer cylinder 2 abutting against the upper surface of the stop ring 1a. After the inner and outer cylinders 2 are fitted together, they pass through the cavity at the top of the diffuser housing 5 and contact the inner ring of the second high-speed bearing 8. After applying axial pressure to the inner cylinder 1, the stop ring 1a at the bottom of the inner cylinder 1 directly presses against the inner ring of the second high-speed bearing 8, and the pressure is transmitted to the spring 10 below through the second high-speed bearing 8, causing the spring 10 to compress and contract. As the downward pressure continues to be applied, the second high-speed bearing 8 can be slowly pressed into the bearing hole of the diffuser housing 5. When the second high-speed bearing 8 is fully installed, the locking head 3b of the fixing rod 3 is then inserted into the groove 2a of the outer cylinder 2 and into the bottom of the central cavity circular hole 5a of the diffuser housing 5. At this time, the outer cylinder 2 is axially positioned by the locking action of the fixing rod 3, which can continuously press against the stop ring 1a at the bottom of the inner cylinder 1, and stably fix the second high-speed bearing 8 in the bearing hole of the diffuser housing 5.

[0056] The main function of the guide is to guide the centering and positioning of the rotor shaft 6, ensuring that the rotor shaft and the two high-speed bearings are always in the same vertical plane, while preventing the rotor shaft 6 from rubbing against the inner ring and bushing 9 of the bearing installed in the bearing hole.

[0057] In this embodiment, the guide is a centering cylinder 4, which is a hollow cylinder with openings at both ends. The lower part of the centering cylinder 4 is provided with a chamfer 4a, the angle of which is 25°. The angle of the chamfer 4a can also be taken in the range of 15°-30°. The diameter of the outer cylinder 2 of the centering cylinder 4 is equal to the inner ring diameter of the two high-speed bearings and the inner hole diameter of the inner cylinder 1. The rotor shaft 6 has a shaft end 6a located at the uppermost end and a connecting part 6b connected to the shaft end 6a for tight fit with the inner ring of the two high-speed bearings. The diameter of the shaft end 6a is smaller than the diameter of the connecting part 6b. The upper connecting section of the connecting part 6b at the upper end corresponds to the inner ring of the second high-speed bearing 8 at the upper end, and the lower connecting section of the connecting part 6b at the upper end corresponds to the inner ring of the first high-speed bearing 7 at the lower end. The upper connecting section and the lower connecting section have the same size, while the intermediate connecting section of the connecting part 6b between the upper connecting section and the lower connecting section has a smaller size than the upper connecting section and the lower connecting section. The intermediate connecting section is used for assembly with the bushing 9.

[0058] The inner diameter of the centering cylinder 4 is equal to the diameter of the end 6a of the rotor shaft 6; the length of the centering cylinder 4 is greater than the distance between the two high-speed bearings. The distance between the two high-speed bearings refers to the distance between the lower surface of the second high-speed bearing 8 and the upper surface of the first high-speed bearing 7, and is usually greater than 3.5 cm.

[0059] The inner wall of the centering cylinder 4 is polished to reduce the frictional resistance when the shaft end 6a of the rotor shaft 6 passes through the centering cylinder 4, thereby reducing the risk of damage to the shaft end 6a. In use, the centering cylinder 4 is fitted onto the shaft end 6a of the rotor shaft 6, and the central axes of the centering cylinder 4, the rotor shaft 6, and the bearing hole coincide.

[0060] During assembly, the centering cylinder 4 is positioned within the inner rings of the two high-speed bearings, with its top extending upwards into the inner cylinder 1. Since the diameter of the outer cylinder 2 of the centering cylinder 4 is equal to the inner diameter of the inner cylinder 1, the centering cylinder 4 will not exhibit radial offset relative to the inner cylinder 1. Therefore, when installing the rotor shaft 6, the centering cylinder 4 can guide the centering and positioning of the rotor shaft 6, preventing radial offset during installation. Simultaneously, the centering cylinder 4 can guide the rotor shaft 6 to pass smoothly along its axial direction, preventing friction between the rotor shaft 6 and the bearing inner rings and bushings 9, thus achieving the purpose of non-destructive assembly of the rotor shaft 6. This simultaneously satisfies the dual requirements of "counteracting spring force" and "maintaining vertical alignment."

[0061] In this embodiment, all components of the assembly kit are made of stainless steel, which can withstand the pressure and wear during the assembly process and has a long service life.

[0062] The method for installing an aircraft starter rotor using the above-mentioned combination kit includes the following steps:

[0063] (1) Preliminary preparation: Clean the bearing holes of the aircraft starter diffuser housing 5 and the bushing 9, spring 10 and first high-speed bearing 7 that have been installed in the bearing holes to ensure that there are no impurities; check the size and surface condition of each component of the assembly kit to confirm that there are no deformation or scratches.

[0064] (2) Installation preparation of the second high-speed bearing 8: Place the second high-speed bearing 8 into the diffuser housing 5, align the inner ring of the second high-speed bearing 8 with the bushing 9, align the outer ring with the spring 10, and align the second high-speed bearing 8 with the bearing hole of the diffuser housing 5 for installation.

[0065] (3) Installation of fixed components: With the end of the inner cylinder 1 with the stop ring 1a facing down, put the outer cylinder 2 on the inner cylinder 1, and then put the inner cylinder 1 and the outer cylinder 2 into the cavity at the top of the diffuser housing 5 until the stop ring 1a at the bottom of the inner cylinder 1 contacts the inner ring of the second high-speed bearing 8.

[0066] (4) Installation of the second high-speed bearing 8: Apply uniform axial pressure to the inner cylinder 1 and slowly push the second high-speed bearing 8 downward until the second high-speed bearing 8 is fully inserted into the bearing hole of the diffuser housing 5. After the second high-speed bearing 8 is installed in place, the central axis of the two high-speed bearings, the central axis of the bushing 9 and the central axis of the bearing hole coincide. At this time, the groove 2a of the outer cylinder 2 is aligned with the bottom of the central cavity circular hole 5a of the diffuser housing 5.

[0067] (5) Fixing component locking: After the second high-speed bearing 8 is installed in place, the fixing locking rod 3 is inserted. The locking head 3b of the fixing locking rod 3 is inserted into the groove 2a of the outer cylinder 2 and abuts against the bottom of the central cavity round hole 5a of the diffuser housing 5, locking the inner and outer cylinders 2 and the diffuser housing 5 as a whole to counteract the spring force of the spring 10 and lock the position of the two high-speed bearings.

[0068] (6) Liquid nitrogen cooling of the rotor: The rotor is placed in liquid nitrogen for cooling, and the rotor shaft diameter is reduced to be smaller than the inner ring diameter of the two high-speed bearings, so that it can pass through the inner ring of the two high-speed bearings.

[0069] (7) Guide component installation: After locking, the overall diffuser housing 5 and the fixing assembly are mounted on the rotor shaft 6 of the starter rotor from top to bottom. The rotor shaft 6 has a shaft end 6a at the uppermost end and a connecting part 6b connected to the shaft end 6a for tight fit with the inner rings of the two high-speed bearings. The diameter of the shaft end 6a is smaller than the diameter of the connecting part 6b. A stepped surface is formed at the intersection of the shaft end 6a and the connecting part 6b. At this time, the inner ring of the first high-speed bearing 7 located below touches the rotor shaft 6. Then, the end of the centering cylinder 4 with the chamfer 4a is inserted into the inner cylinder 1. The centering cylinder 4 passes down through the second high-speed bearing 8, the bushing 9, and the first high-speed bearing 7 and is mounted on the shaft end 6a of the rotor shaft 6. After mounting, the lower end face of the centering cylinder 4 contacts the stepped surface where the shaft end 6a of the rotor shaft 6 and the connecting part 6b intersect. The top end of the centering cylinder 4 extends upward into the inner cylinder 1.

[0070] (8) Installation of rotor shaft 6: Pressure is applied to the inner cylinder 1 by the press. The pressure is transmitted to the inner ring of the first high-speed bearing 7 through the inner cylinder 1 stop ring 1a, the inner ring of the second high-speed bearing 8, and the bushing 9. The rotor shaft 6 passes through the inner ring of the first high-speed bearing 7, the bushing 9 and the inner ring of the second bearing in sequence from the lower part of the diffuser housing 5 until the connecting part 6b of the rotor shaft 6 is located in the inner ring of the two high-speed bearings, so as to meet the installation requirements of the rotor shaft 6. The centering cylinder 4 ensures that the three central axes of the rotor shaft 6 line, the centering cylinder 4 axis and the bearing hole axis coincide.

[0071] (9) Finishing: After the rotor shaft 6 is installed in place, since the rotor shaft 6 and the inner rings of the two high-speed bearings are tightly fitted, when the diameter of the rotor shaft increases and returns to the size at room temperature after the liquid nitrogen cooling effect disappears, the inner rings of the two high-speed bearings tightly fit the connecting part 6b of the rotor shaft 6, completing the transfer of the aircraft starter rotor. After that, the fixing lock rod 3, outer cylinder 2, inner cylinder 1 and centering cylinder 4 are removed.

[0072] After the rotor is assembled, check the assembly quality to ensure it meets the requirements of the Aircraft Component Maintenance Manual (CMM).

[0073] The above embodiments of the present invention are not intended to limit the scope of protection of the present invention. The implementation of the present invention is not limited thereto. All other modifications, substitutions or alterations made to the method of the present invention based on the above content of the present invention, in accordance with ordinary technical knowledge and common practice in the field, without departing from the basic technical concept of the present invention, shall fall within the scope of protection of the present invention.

Claims

1. A combination kit for installing an aircraft starter rotor, characterized in that: The kit includes a fixing component and a guide component; The fixing component includes: Inner cylinder: The inner cylinder is a hollow cylinder with open ends. The inner diameter of the inner cylinder is equal to the inner ring diameter of the second high-speed bearing and the first high-speed bearing, which are distributed vertically in the bearing hole of the aircraft starter diffuser housing. A convex retaining ring is integrally formed at the bottom of the inner cylinder. Outer cylinder: The outer cylinder is a hollow cylinder with open ends. The inner diameter of the outer cylinder is equal to the outer diameter of the inner cylinder. The lower end face of the outer cylinder abuts against the upper surface of the stop ring. A groove is formed in the middle of the outer surface of the outer cylinder. The height of the groove is such that when the outer cylinder and the inner cylinder are pressed down by the stop ring under the action of external force, so that the second high-speed bearing is fully inserted into the bearing hole of the diffuser housing, the groove is facing the bottom of the central cavity of the diffuser housing. Fixed locking rod: The fixed locking rod includes a rod part and a locking head. The inner edge of the locking head is adapted to the groove of the outer cylinder. When the second high-speed bearing is fully inserted into the bearing hole of the diffuser housing, the inner edge of the locking head is inserted into the groove of the outer cylinder, and the outer edge abuts against the bottom of the central cavity of the diffuser housing, thereby locking the inner and outer cylinders and the diffuser housing as a whole, and thus fixing the second high-speed bearing and the first high-speed bearing. The guide component is a centering cylinder, which is a hollow cylinder open at both ends. The lower part of the centering cylinder is chamfered. The outer diameter of the centering cylinder is equal to the inner ring diameter of the two high-speed bearings and the inner diameter of the inner cylinder. The rotor shaft has a shaft end located at the uppermost end and a connecting part connected to the shaft end for tight fit with the inner ring of the two high-speed bearings. The diameter of the shaft end is smaller than the diameter of the connecting part. The inner diameter of the centering cylinder is equal to the diameter of the shaft end of the rotor shaft. In use, the centering cylinder is fitted onto the shaft end of the rotor shaft.

2. The assembly kit for installing an aircraft starter rotor according to claim 1, characterized in that: The fixed locking rod is Y-shaped overall, with a straight rod at the top and a U-shaped locking head.

3. The assembly kit for installing an aircraft starter rotor according to claim 1, characterized in that: The chamfer angle is 15°-30°.

4. The assembly kit for installing an aircraft starter rotor according to claim 1, characterized in that: The inner wall of the centering cylinder is polished to reduce the frictional resistance when the rotor shaft end passes through the centering cylinder, thereby reducing the risk of damage to the shaft end.

5. The assembly kit for installing an aircraft starter rotor according to claim 1, characterized in that: The length of the centering cylinder is greater than the distance between the two high-speed bearings, and the distance between the two high-speed bearings refers to the distance between the lower surface of the second high-speed bearing and the upper surface of the first high-speed bearing.

6. A method for installing an aircraft starter rotor using the combined kit according to any one of claims 1 to 5, characterized in that, The installation method includes the following steps: (1) Preliminary preparation: Clean the bearing holes of the aircraft starter diffuser housing and the bushings, springs and first high-speed bearings already installed in the bearing holes to ensure that there are no impurities; check the size and surface condition of each component of the assembly kit to confirm that there are no deformation or scratches. (2) Preparation for installation of the second high-speed bearing: Place the second high-speed bearing into the diffuser housing, align the inner ring of the second high-speed bearing with the bushing, align the outer ring with the spring, and align the second high-speed bearing with the bearing hole of the diffuser housing for installation. (3) Installation of fixed components: With the end of the inner cylinder with the retaining ring facing down, put the outer cylinder on the inner cylinder, and then put the inner cylinder and the outer cylinder into the cavity at the top of the diffuser housing until the retaining ring at the bottom of the inner cylinder contacts the inner ring of the second high-speed bearing; (4) Installation of the second high-speed bearing: Apply uniform axial pressure to the inner cylinder and slowly push the second high-speed bearing downward until the second high-speed bearing is fully inserted into the bearing hole of the diffuser housing. After the second high-speed bearing is installed in place, the central axis of the two high-speed bearings, the central axis of the bushing and the central axis of the bearing hole coincide. At this time, the groove of the outer cylinder is facing the bottom of the central cavity of the diffuser housing. (5) Fixing component locking: After the second high-speed bearing is installed in place, insert the fixing locking rod. The locking head of the fixing locking rod is inserted into the groove of the outer cylinder and abuts against the bottom of the middle cavity of the diffuser housing, locking the inner and outer cylinders and the diffuser housing as a whole to counteract the spring force of the spring and lock the position of the two high-speed bearings. (6) Liquid nitrogen cooling of the rotor: The rotor is placed in liquid nitrogen for cooling, and the rotor shaft diameter is reduced to be smaller than the inner ring diameter of the two high-speed bearings, so that it can pass through the inner ring of the two high-speed bearings. (7) Guide component installation: After locking, the entire diffuser housing and fixing assembly are mounted on the rotor shaft of the starter rotor from top to bottom. The rotor shaft has a shaft end at the uppermost end and a connecting part connected to the shaft end for tight fit with the inner rings of the two high-speed bearings. The diameter of the shaft end is smaller than the diameter of the connecting part. A stepped surface is formed at the intersection of the shaft end and the connecting part. At this time, the inner ring of the first high-speed bearing located below touches the rotor shaft. Then, the chamfered end of the centering cylinder is placed into the inner cylinder. The centering cylinder passes downward through the second high-speed bearing, the bushing, and the first high-speed bearing before being mounted on the shaft end of the rotor shaft. After mounting, the lower end face of the centering cylinder contacts the stepped surface where the shaft end of the rotor shaft and the connecting part intersect. The top end of the centering cylinder extends upward into the inner cylinder. (8) Rotor shaft installation: Pressure is applied to the inner cylinder by the press. The pressure is transmitted to the inner ring of the first high-speed bearing through the inner cylinder retaining ring, the inner ring of the second high-speed bearing, and the bushing. The rotor shaft passes through the inner ring of the first high-speed bearing, the bushing, and the inner ring of the second bearing in sequence from the bottom of the diffuser housing upwards until the connecting part of the rotor shaft is located in the inner ring of the two high-speed bearings, thus achieving the requirement of the rotor shaft being installed in place. The centering cylinder ensures that the three central axes of the rotor shaft, the centering cylinder axis, and the bearing hole axis are coincident. (9) Finishing: After the rotor shaft is installed in place, since the rotor shaft and the inner rings of the two high-speed bearings are tightly fitted, when the diameter of the rotor shaft increases and returns to the size at room temperature after the liquid nitrogen cooling effect disappears, the inner rings of the two high-speed bearings tightly fit the connecting part of the rotor shaft, completing the conversion of the aircraft starter rotor. After that, the fixing lock rod, outer cylinder, inner cylinder and centering cylinder are removed.

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