High and low pressure rotors with a common bearing cavity and turbofan engine

Abstract

The present invention discloses a high-low pressure rotor with a common bearing cavity and a turbofan engine, which includes a low-pressure rotor, a high-pressure rotor, a support assembly, a first lubricating oil nozzle, and a second lubricating oil nozzle. The low-pressure rotor and the high-pressure rotor are concentrically arranged. The support assembly includes a front bearing housing provided with a front bearing cavity, a first bearing disposed in the front bearing cavity and supporting the low-pressure rotor, a second bearing disposed in the front bearing cavity and supporting the low-pressure rotor, a third bearing disposed in the front bearing cavity and supporting the high-pressure rotor, a rear bearing housing provided with a rear bearing cavity, a fourth bearing disposed in the rear bearing cavity and supporting the high-pressure rotor, a fifth bearing disposed in the rear bearing cavity and supporting the low-pressure rotor, and a sixth bearing disposed in the rear bearing cavity and supporting the low-pressure rotor. Compared with the prior art, it has the characteristics of fewer parts, simple structure, compact axial dimension, small vibration, and high reliability, which is convenient for engine weight control and cost reduction of the engine, and is suitable for wide promotion and application.

Description

Technical Field

[0001] The present invention relates to the technical field of engine rotor structure layout, and particularly to a high and low pressure rotor with a common bearing cavity. In addition, the present invention also relates to a turbofan engine including the high and low pressure rotor with the common bearing cavity as described above. Background Art

[0002] The rotor is the core component of the engine, and the rotor layout is the most prominent structural feature of the engine, which determines the structural layout and vibration characteristics of the engine. For medium and small thrust turbofan engines, a single low pressure rotor and a single high pressure rotor design are usually adopted.

[0003] Currently, the layouts of the high and low pressure rotors in the world's mainstream medium and small thrust turbofan engines are different, such as:

[0004] 1) The PW545 engine of Pratt & Whitney, its high pressure rotor adopts a 1-0-1 support form, including a 2A+1C combined compressor and a 1-stage axial high pressure turbine, and its low pressure rotor adopts a 0-2-1 support form, including a 1-stage fan + a 1-stage intermediate pressure compressor and 3-stage low pressure turbines;

[0005] 2) The FJ44 engine of Williams, its high pressure rotor adopts a 1-0-1 support form, including a 1-stage centrifugal compressor and a 1-stage axial high pressure turbine, and its low pressure rotor adopts a 0-3-0 support form, including a 1-stage fan + 3-stage intermediate pressure compressors and 2-stage low pressure turbines;

[0006] 3) The HF120 engine jointly developed by GE and Honda, its high pressure rotor adopts a 1-stage centrifugal compressor and a 1-stage axial high pressure turbine, and its low pressure rotor adopts a 1-stage fan + 2-stage intermediate pressure compressors and 2-stage low pressure turbines.

[0007] The advantages of the rotor layouts of the above 3 types of engines are that the high pressure turbine has a simple structure and a compact layout, and the multi-stage low pressure rotor is beneficial to the improvement of the engine pressure ratio. However, the disadvantages are that the number of disk stages of the low pressure rotor is relatively large, the structure of the rotor is complex, and the number of load-bearing structures of the rotor is large. Correspondingly, the number of lubricating oil paths and seal air flow paths is large, resulting in a large number of engine parts, which is not conducive to the weight reduction design, cost reduction and reliability improvement of the engine. Summary of the Invention

[0008] The present invention provides a high and low pressure rotor with a common bearing cavity and a turbofan engine to solve the technical problems that the rotor layout structure in the existing turbofan engine is complex, the number of parts is large, it is not conducive to the weight reduction design of the engine, and the reliability is low.

[0009] According to one aspect of the present invention, there is provided a high-low pressure rotor with a common bearing cavity, including a low-pressure rotor, a high-pressure rotor, a support assembly, a first lubricating oil nozzle, and a second lubricating oil nozzle. The low-pressure rotor and the high-pressure rotor are concentrically arranged. The support assembly includes a front bearing housing with a front bearing cavity, a first bearing disposed in the front bearing cavity and supporting the low-pressure rotor, a second bearing disposed in the front bearing cavity and supporting the low-pressure rotor, a third bearing disposed in the front bearing cavity and supporting the high-pressure rotor, a rear bearing housing with a rear bearing cavity, a fourth bearing disposed in the rear bearing cavity and supporting the high-pressure rotor, a fifth bearing disposed in the rear bearing cavity and supporting the low-pressure rotor, and a sixth bearing disposed in the rear bearing cavity and supporting the low-pressure rotor. The first lubricating oil nozzle is disposed in the front bearing cavity for spray lubricating the second bearing and for under-ring lubricating the first bearing and the third bearing. The second lubricating oil nozzle is disposed in the rear bearing cavity for under-ring lubricating the fourth bearing, the fifth bearing, and the sixth bearing.

[0010] As a further improvement of the above technical solution:

[0011] Further, the low-pressure rotor includes a low-pressure long shaft concentrically arranged with the high-pressure rotor, an axial flow fan fixed on the low-pressure long shaft, a low-pressure short shaft connected to the low-pressure long shaft, and a two-stage axial flow low-pressure turbine disposed on the low-pressure short shaft.

[0012] Further, the low-pressure long shaft is axially provided with an axial drainage hole one for guiding the axial inflow of lubricating oil, and the low-pressure long shaft is radially provided with a radial drainage hole one for guiding the lubricating oil to flow to the first bearing.

[0013] Further, the low-pressure short shaft is axially provided with an axial drainage hole two for guiding the inflow of lubricating oil, and the low-pressure short shaft is radially provided with a radial drainage hole two for guiding the lubricating oil to flow to the fifth bearing and a radial drainage hole three for guiding the lubricating oil to flow to the sixth bearing.

[0014] Further, the high-pressure rotor includes a central tie rod sleeved outside the low-pressure long shaft, a combined compressor fixed on the central tie rod, and a two-stage axial flow high-pressure turbine fixed on the central tie rod. The combined compressor includes a three-stage axial flow compressor and a one-stage centrifugal compressor.

[0015] Further, a sealing ring rotating body one for dynamically mating with graphite on the front bearing housing to seal the front end of the front bearing cavity is disposed on the axial flow fan, and a stepped labyrinth is disposed on the three-stage axial flow compressor for mating with the engine stator to seal the rear end of the front bearing cavity.

[0016] Further, axial drainage holes three and four for guiding the inflow of lubricating oil are respectively opened at both axial ends of the central tie rod. The central tie rod is radially provided with a radial drainage hole four for guiding the lubricating oil to flow to the third bearing and a radial drainage hole five for guiding the lubricating oil to flow to the fourth bearing.

[0017] Furthermore, the first bearing is a ball bearing for bearing the axial force and radial force of the low-pressure rotor, and the second bearing is a roller bearing for bearing the radial force of the low-pressure rotor; and / or the first bearing and the sixth bearing are elastic supports, and the second bearing and the fifth bearing are rigid supports.

[0018] Furthermore, the third bearing and the fourth bearing are elastic supports.

[0019] According to another aspect of the present invention, there is also provided a turbofan engine, which includes the high and low pressure rotors with the above-mentioned common bearing cavity.

[0020] The present invention has the following beneficial effects:

[0021] For the high and low pressure rotors with the common bearing cavity of the present invention, the supporting assembly realizes the 0-4-0 supporting form for the low-pressure rotor through the front bearing housing, the first bearing, the second bearing, the rear bearing housing, the fifth bearing and the sixth bearing, so as to realize the front and rear double fulcrum layout, which can greatly improve the structural stability of the low-pressure rotor; the 1-0-1 supporting form for the high-pressure rotor is realized through the front bearing housing, the third bearing, the rear bearing housing and the fourth bearing; the first bearing, the second bearing and the third bearing are jointly arranged in the front bearing cavity, and the fourth bearing, the fifth bearing and the sixth bearing are jointly arranged in the rear bearing cavity. By means of the common bearing cavity layout, the number of bearing cavities is reduced, and correspondingly, the number of lubricating oil pipelines, air pipelines, sealing structures and load-bearing structures is reduced, which is beneficial to the weight reduction design of the engine, improves the reliability of the engine. In addition, the common bearing cavity layout can greatly shorten the axial length of the engine, make the engine structure compact, have high space utilization rate, be convenient for the size control of the engine, and can also reduce the bleed air for sealing the bearing cavity, thereby reducing the performance loss caused by the bleed air; the lubrication of all bearings is realized through the combined action of the first lubricating oil nozzle and the second lubricating oil nozzle, and except for the second bearing with a smaller radial dimension which is jet lubrication, other bearings are all under-ring lubrication, so as to improve the utilization rate of the lubricating oil, reduce the lubricating oil flow rate, reduce the size of the oil circuit, and be convenient for the small and light design of the relevant lubricating oil pumps; by adopting the structural layout modes such as the 0-4-0 supported low-pressure rotor, the 1-0-1 supported high-pressure rotor and the under-ring lubrication of the bearings under the common bearing cavity of the high and low pressure rotors, compared with the prior art, the present invention has the characteristics of fewer parts, simple structure, compact axial dimension and high reliability, is convenient for the weight control of the engine and the reduction of the engine cost, improves the reliability of the engine, has strong practicability, and is suitable for wide popularization and application.

[0022] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the drawings. Description of the Drawings

[0023] The accompanying drawings, which form a part of this application, are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0024] Figure 1 is a schematic structural diagram of the high and low pressure rotors of the bearing common cavity of the preferred embodiment of the present invention;

[0025] Figure 2 is Figure 1 a schematic front-end structural diagram of the high and low pressure rotors of the bearing common cavity shown;

[0026] Figure 3 is Figure 1 a schematic rear-end structural diagram of the high and low pressure rotors of the bearing common cavity shown;

[0027] Figure 4 is Figure 2 a schematic rear-end structural diagram of the high and low pressure rotors of the bearing common cavity shown.

[0028] Legend:

[0029] 100, low pressure rotor; 110, low pressure long shaft; 120, axial flow fan; 130, low pressure short shaft; 140, second-stage axial flow low pressure turbine; 200, high pressure rotor; 210, central tie rod; 220, combined compressor; 230, second-stage axial flow high pressure turbine; 310, front bearing housing; 311, front bearing cavity; 320, first bearing; 330, second bearing; 340, third bearing; 350, rear bearing housing; 351, rear bearing cavity; 360, fourth bearing; 370, fifth bearing; 380, sixth bearing; 400, second lubricating oil nozzle; 500, first sealing ring rotating body; 600, stepped labyrinth; 700, second sealing ring rotating body; 800, third sealing ring rotating body. Detailed Description of the Preferred Embodiment

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways defined and covered by the following.

[0031] As Figures 1 - 3As shown, the high and low pressure rotors of the bearing common cavity in this embodiment include a low pressure rotor 100, a high pressure rotor 200, a support assembly, a first lubricating oil nozzle (not shown in the figure), and a second lubricating oil nozzle 400. The low pressure rotor 100 and the high pressure rotor 200 are concentrically arranged. The support assembly includes a front bearing seat 310 provided with a front bearing cavity 311, a first bearing 320 disposed in the front bearing cavity 311 and supporting the low pressure rotor 100, a second bearing 330 disposed in the front bearing cavity 311 and supporting the low pressure rotor 100, a third bearing 340 disposed in the front bearing cavity 311 and supporting the high pressure rotor 200, a rear bearing seat 350 provided with a rear bearing cavity 351, a fourth bearing 360 disposed in the rear bearing cavity 351 and supporting the high pressure rotor 200, a fifth bearing 370 disposed in the rear bearing cavity 351 and supporting the low pressure rotor 100, and a sixth bearing 380 disposed in the rear bearing cavity 351 and supporting the low pressure rotor 100. The first lubricating oil nozzle is disposed in the front bearing cavity 311 for jet lubrication of the second bearing 330 and under-ring lubrication of the first bearing 320 and the third bearing 340. The second lubricating oil nozzle 400 is disposed in the rear bearing cavity 351 for under-ring lubrication of the fourth bearing 360, the fifth bearing 370, and the sixth bearing 380.

[0032] As Figures 1 - 3As shown in the figure, specifically, for the high and low pressure rotors with a common bearing cavity in the present invention, the supporting assembly realizes the 0-4-0 supporting form for the low pressure rotor 100 through the front bearing housing 310, the first bearing 320, the second bearing 330, the rear bearing housing 350, the fifth bearing 370 and the sixth bearing 380, so as to achieve the front and rear double fulcrum layout, which can greatly improve the structural stability of the low pressure rotor and reduce vibration; through the front bearing housing 310, the third bearing 340, the rear bearing housing 350 and the fourth bearing 360, the 1-0-1 supporting form for the high pressure rotor 200 is realized, so as to ensure that the high pressure rotor 200 avoids the critical speed within a wide speed range, avoiding the limitation of engine use due to vibration problems and facilitating the expansion of the subsequent working speed range; the first bearing 320, the second bearing 330 and the third bearing 340 are jointly arranged in the front bearing cavity 311, and the fourth bearing 360, the fifth bearing 370 and the sixth bearing 380 are jointly arranged in the rear bearing cavity 351. By means of the common bearing cavity layout, the number of bearing cavities is reduced, and correspondingly, the number of lubricating oil pipelines, air pipelines, sealing structures and load-bearing structures is reduced, which is beneficial to the weight reduction design of the engine, improves the reliability of the engine. In addition, the common bearing cavity layout can greatly shorten the axial length of the engine, making the engine structure compact, with high space utilization rate, facilitating the size control of the engine, and can also reduce the bleed air for sealing the bearing cavity, thereby reducing the performance loss caused by bleed air; through the combined action of the first lubricating oil nozzle and the second lubricating oil nozzle 400, the lubrication of all bearings is realized, and except for the second bearing 330 with a relatively small radial dimension which is jet lubrication, other bearings are all under-ring lubrication, so as to improve the utilization rate of lubricating oil, reduce the lubricating oil flow rate, reduce the size of the oil circuit, and facilitate the small and light design of the relevant lubricating oil pumps; by adopting structural layout methods such as the low pressure rotor 100 with 0-4-0 support, the high pressure rotor 200 with 1-0-1 support and the under-ring lubrication of the bearings under the common bearing cavity of the high and low pressure rotors, compared with the prior art, it has the characteristics of fewer parts, simple structure, compact axial dimension, small vibration and high reliability, which is convenient for engine weight control and cost reduction of the engine, has strong practicability, and is suitable for wide promotion and application.

[0033] It should be understood that under-ring lubrication means that the lubricating oil is sprayed by the lubricating oil nozzle and then enters the internal oil supply channels of the corresponding rotating shafts (such as the low pressure long shaft 110, the low pressure short shaft 130 and the central pull rod 210), and then enters the rollers from the inner ring of the bearing for bearing heat dissipation and lubrication. Compared with the method of directly spraying the lubricating oil onto the bearing rollers, the utilization rate of the lubricating oil is high, reaching more than 95%; due to the high efficiency of the under-ring lubrication method, under the condition of the same heat dissipation requirement, less lubricating oil is required, correspondingly, the lubricating oil flow rate can be reduced, the size of the oil circuit can be reduced, and at the same time, the capacity requirement for the lubricating oil pump is also lower, which is convenient for the small and light design of the lubricating oil pump.

[0034] It should be understood that the high-pressure and low-pressure rotors of the bearing common cavity are the core components of the engine, and thus their beneficial effects are mainly reflected in the performance optimization of the engine.

[0035] It should be understood that the lubricating oil pipeline is used to lubricate the bearings in the bearing cavity, the air pipeline is used for sealing and bleeding air in the bearing cavity, the sealing structure is used to seal the bearing cavity, and the load-bearing structure is used to support the rotor and transfer the load. Therefore, when the number of bearing cavities is reduced, the number of the above-mentioned related structures will also be reduced accordingly, thus greatly reducing the number of parts, facilitating the weight control of the engine, reducing the cost of the engine, and improving the reliability of the engine.

[0036] As Figure 1 shown, in this embodiment, the low-pressure rotor 100 includes a low-pressure long shaft 110 concentrically arranged with the high-pressure rotor 200, an axial-flow fan 120 fixed on the low-pressure long shaft 110, a low-pressure short shaft 130 connected to the low-pressure long shaft 110, and a two-stage axial-flow low-pressure turbine 140 arranged on the low-pressure short shaft 130. Specifically, the disk of the axial-flow fan 120 is fixed on the low-pressure long shaft 110 by an axial nut and transmits torque to the low-pressure long shaft 110 through a spline; the low-pressure long shaft 110 and the low-pressure short shaft 130 are concentrically arranged, connected and fixed by an axial nut, and transmit torque through a spline; the two-stage axial-flow low-pressure turbines 140 are connected by bolts and nuts, and the two-stage axial-flow low-pressure turbine 140 and the low-pressure short shaft 130 transmit torque through arc end teeth.

[0037] As Figure 2 shown, in this embodiment, the low-pressure long shaft 110 is axially provided with a first axial drainage hole for guiding the axial inflow of lubricating oil, and the low-pressure long shaft 110 is radially provided with a first radial drainage hole for guiding the lubricating oil to flow to the first bearing 320. Specifically, when the first lubricating oil nozzle sprays lubricating oil in the front bearing cavity 311, the lubricating oil flows axially into the low-pressure long shaft 110 through the axial drainage hole and then flows radially to the first bearing 320 through the radial drainage hole to achieve under-ring lubrication of the first bearing 320.

[0038] It should be understood that since the radial dimension of the second bearing 330 is relatively small and it is difficult to open the drainage hole, the lubrication method of the second bearing 330 is spray lubrication.

[0039] As Figure 3As shown in the figure, in this embodiment, the low-pressure short shaft 130 is axially provided with a second axial drainage hole for guiding the lubricating oil to flow in, and the low-pressure short shaft 130 is radially provided with a second radial drainage hole for guiding the lubricating oil to flow to the fifth bearing 370 and a third radial drainage hole for guiding the lubricating oil to flow to the sixth bearing 380. Specifically, after the second lubricating oil nozzle 400 sprays the lubricating oil in the rear bearing cavity 351, the lubricating oil flows into the low-pressure short shaft 130 axially through the second axial drainage hole, and then flows to the fifth bearing 370 radially through the second radial drainage hole and to the sixth bearing 380 through the radial drainage hole, thereby realizing the under-ring lubrication of the fifth bearing 370 and the sixth bearing 380.

[0040] As Figure 1 shown in the figure, in this embodiment, the high-pressure rotor 200 includes a central tie rod 210 sleeved outside the low-pressure long shaft 110, a combined compressor 220 fixed on the central tie rod 210, and a two-stage axial-flow high-pressure turbine 230 fixed on the central tie rod 210. The combined compressor 220 includes a three-stage axial-flow compressor and a single-stage centrifugal compressor. Specifically, the high-pressure rotor 200 adopts the configuration of a 3A + 1C combined compressor 220 and a two-stage axial-flow high-pressure turbine 230, which can greatly improve the working efficiency of the combined compressor 220, increase the surge margin, and make the load of the two-stage axial-flow high-pressure turbine 230 low, with higher safety and longer service life.

[0041] It should be understood that A refers to an axial-flow compressor and C refers to a centrifugal compressor.

[0042] As Figure 4As shown in the figure, in this embodiment, a first sealing ring rotating body 500 for dynamically mating with graphite on the front bearing housing 310 to seal the front end of the front bearing cavity 311 is arranged on the axial flow fan 120, and a stepped labyrinth 600 for mating with the engine stator to seal the rear end of the front bearing cavity 311 is arranged on the three-stage axial flow compressor. Specifically, the front end of the front bearing cavity 311 is sealed by the dynamic mating of the first sealing ring rotating body 500 with the graphite on the front bearing housing 310 to achieve floating ring graphite sealing. The floating ring graphite sealing can radially float according to the vibration of the rotor, ensuring that the sealing clearance remains unchanged in all states of the rotor. At the same time, high-pressure sealing gas is introduced through the air supply channel to ensure the sealing effect. This sealing structure is simple and reliable, and there will be no permanent increase in the sealing clearance caused by wear between the rotating and static parts. It has the advantages of good sealing effect and long service life. The flow channel at the rear end of the front bearing cavity 311 is relatively low and the space is limited. Therefore, the rear end of the front bearing cavity 311 is sealed by the cooperation of the stepped labyrinth 600 and the engine stator. The stepped labyrinth 600 can achieve multi-labyrinth sealing (double-labyrinth sealing in this embodiment). High-pressure gas can be introduced into the sealing between adjacent labyrinths by using the disk cavity clearance of the combined compressor 220. Only two holes need to be drilled on the journal of the compressor disk to achieve air supply and sealing. The structure is simple and reliable. Through the stepped labyrinth 600 and high-pressure gas sealing, the sealing ability can be greatly improved, and to a large extent, the reduction of the sealing effect caused by the increase of the air supply sealing clearance due to labyrinth scraping and abrasion can be avoided. Optionally, the stepped labyrinth 600 is arranged on the journal of the first-stage axial flow compressor, and air supply sealing holes for introducing compressed air between the two labyrinths are provided on the journal of the first-stage axial flow compressor.

[0043] It should be understood that the combined sealing form of the floating ring graphite sealing and the stepped labyrinth 600 improves the service life of the sealing parts while taking into account the sealing performance, thereby improving the reliability of the engine.

[0044] As Figure 3 As shown in the figure, in this embodiment, a second sealing ring rotating body 700 for dynamically mating with graphite on the rear bearing housing 350 to seal the front end of the rear bearing cavity 351 is arranged on the high-pressure rotor 200, and a third sealing ring rotating body 800 for dynamically mating with graphite on the rear bearing housing 350 to seal the rear end of the rear bearing cavity 351 is arranged on the low-pressure rotor 100. The floating ring graphite sealing at the front and rear ends of the rear bearing cavity 351 is achieved through the second sealing ring rotating body 700 and the third sealing ring rotating body 800. The floating ring graphite sealing can radially float according to the vibration of the rotor, ensuring that the sealing clearance remains unchanged in all states of the rotor. At the same time, high-pressure sealing gas is introduced through the air supply channel to ensure the sealing effect. This sealing structure is simple and reliable, and there will be no permanent increase in the sealing clearance caused by wear between the rotating and static parts. It has the advantages of good sealing effect and long service life.

[0045] It should be understood that the engine stator component that is hermetically sealed in cooperation with the stepped labyrinth seal 600 is located outside the front bearing housing 310.

[0046] As Figure 2 and Figure 3 shown, in this embodiment, axial drainage holes three and four for guiding lubricating oil to flow in are respectively formed at both axial ends of the central pull rod 210. The central pull rod 210 is provided with a radial drainage hole four for guiding lubricating oil to flow to the third bearing 340 and a radial drainage hole five for guiding lubricating oil to flow to the fourth bearing 360 along the radial direction. Specifically, after the first lubricating oil nozzle sprays lubricating oil in the front bearing cavity 311, the lubricating oil enters the central pull rod 210 axially through the axial drainage hole three, and then flows to the third bearing 340 radially through the radial drainage hole four to achieve under-ring lubrication of the third bearing 340; after the second lubricating oil nozzle 400 sprays lubricating oil in the rear bearing cavity 351, the lubricating oil flows into the central pull rod 210 axially through the axial drainage hole four, and then flows to the fourth bearing 360 radially through the radial drainage hole five to achieve under-ring lubrication of the fourth bearing 360.

[0047] In this embodiment, the first bearing 320 is a ball bearing, which is used to bear the axial force and radial force of the low-pressure rotor 100. The second bearing 330 is a roller bearing, which is used to bear the radial force of the low-pressure rotor 100. Specifically, the axial force and radial force of the low-pressure rotor 100 are borne by the first bearing 320, and then the radial force of the low-pressure rotor 100 is borne by the second bearing 330. By adopting the double-pivot layout of the first bearing 320 and the second bearing 330, the ability of the low-pressure long shaft 110 to resist the bending moment brought by the disk of the axial-flow fan 120 can be greatly improved, the deflection of the low-pressure long shaft 110 can be reduced, and the working stability of the low-pressure rotor can be improved.

[0048] As Figure 1 shown, in this embodiment, the rear end of the low-pressure rotor 100 is supported by the fifth bearing 370 and the sixth bearing 380 as pivots. The sixth bearing 380 is located near the center of the two-stage axial-flow low-pressure turbine, which can effectively reduce the bending moment generated during the high-speed operation of the two-stage axial-flow low-pressure turbine. By adopting the double-pivot layout of the fifth bearing 370 and the sixth bearing 380, the ability of the low-pressure short shaft 130 to resist the bending moment brought by the two-stage axial-flow low-pressure turbine can be greatly improved, the deflection of the low-pressure short shaft 130 can be reduced, and the working stability of the low-pressure rotor can be improved.

[0049] In this embodiment, the first bearing 320 and the sixth bearing 380 are elastic supports, and the second bearing 330 and the fifth bearing 370 are rigid supports. Specifically, through the elastic support of the first bearing 320 and the sixth bearing 380, the support stiffness of the support assembly to the low-pressure rotor 100 can be adjusted to obtain satisfactory dynamic characteristics of the low-pressure rotor 100, so that the critical speed of the low-pressure rotor 100 can avoid the common operating speed of the engine, avoid the vibration stability caused by resonance, and the vibration of the low-pressure rotor 100 is small, which can avoid the limitation of engine use due to vibration problems and provide convenience for the subsequent expansion of the operating speed range. Optionally, the first bearing 320 and the sixth bearing 380 use squirrel cage elastic supports to achieve elastic support.

[0050] In this embodiment, the third bearing 340 and the fourth bearing 360 are elastic supports, so that the critical speed of the high-pressure rotor 200 can avoid the common working speed of the engine, avoid the vibration stability caused by resonance, and the vibration of the high-pressure rotor 200 is small, which can avoid the limitation of engine use due to vibration problems and provide convenience for the subsequent expansion of the working speed range. Optionally, the third bearing 340 and the fourth bearing 360 use squirrel cage elastic supports to achieve elastic support

[0051] It should be understood that when the operating speed of the rotor approaches or reaches the critical speed, resonance will occur, causing the amplitude to increase sharply and produce violent vibrations.

[0052] The turbofan engine of this embodiment includes the high- and low-pressure rotors with a common bearing cavity as described above. Since the technical effect of the turbofan engine provided by this embodiment is the same as the technical effect of the high- and low-pressure rotors with a common bearing cavity provided by the above embodiment, they will not be described in detail here.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high- and low-pressure rotor with a common bearing cavity, characterized in that: The invention comprises a low-pressure rotor (100), a high-pressure rotor (200), a support assembly, a first lubricating oil nozzle and a second lubricating oil nozzle (400), wherein the low-pressure rotor (100) and the high-pressure rotor (200) are arranged concentrically, and the support assembly comprises a front bearing seat (310) having a front bearing cavity (311), a first bearing (320) arranged in the front bearing cavity (311) and supporting the low-pressure rotor (100), a second bearing (330) arranged in the front bearing cavity (311) and supporting the low-pressure rotor (100), a third bearing (340) arranged in the front bearing cavity (311) and supporting the high-pressure rotor (200), a rear bearing seat (350) having a rear bearing cavity (351), and a rear bearing seat (351) arranged in the rear axle. a fourth bearing (360) arranged in the bearing cavity (351) and supporting the high-pressure rotor (200), a fifth bearing (370) arranged in the rear bearing cavity (351) and supporting the low-pressure rotor (100), and a sixth bearing (380) arranged in the rear bearing cavity (351) and supporting the low-pressure rotor (100); a first lubricating oil nozzle arranged in the front bearing cavity (311) and used for performing jet lubrication on the second bearing (330) and performing under-ring lubrication on the first bearing (320) and the third bearing (340); and a second lubricating oil nozzle (400) arranged in the rear bearing cavity (351) and used for performing under-ring lubrication on the fourth bearing (360), the fifth bearing (370) and the sixth bearing (380); The low-pressure rotor (100) comprises a low-pressure long shaft (110) arranged concentrically with the high-pressure rotor (200), an axial-flow fan (120) fixed on the low-pressure long shaft (110), a low-pressure short shaft (130) connected to the low-pressure long shaft (110), and a two-stage axial-flow low-pressure turbine (140) arranged on the low-pressure short shaft (130); The high-pressure rotor (200) comprises a central tie rod (210) sleeved outside the low-pressure long shaft (110), a combined compressor (220) fixed on the central tie rod (210), and a two-stage axial-flow high-pressure turbine (230) fixed on the central tie rod (210), wherein the combined compressor (220) comprises a three-stage axial-flow compressor and a one-stage centrifugal compressor; The axial flow fan (120) is provided with a sealing ring rotating body (500) for dynamically cooperating with graphite on the front bearing seat (310) to seal the front end of the front bearing cavity (311), and the three-stage axial flow compressor is provided with a stepped comb tooth (600) for cooperating with the engine stator to seal the rear end of the front bearing cavity (311).

2. The high- and low-pressure rotor with a common bearing cavity according to claim 1, characterized in that: The low-pressure long shaft (110) is provided with an axial drainage hole one for guiding the axial inflow of lubricating oil, and the low-pressure long shaft (110) is provided with a radial drainage hole one for guiding the lubricating oil to flow toward the first bearing (320) along the radial direction.

3. The high- and low-pressure rotor with a common bearing cavity according to claim 1, characterized in that: The low-pressure short shaft (130) is provided with an axial drainage hole 2 for guiding the lubricating oil to flow in along the axial direction, and the low-pressure short shaft (130) is provided with a radial drainage hole 2 for guiding the lubricating oil to flow to the fifth bearing (370) and a radial drainage hole 3 for guiding the lubricating oil to flow to the sixth bearing (380) along the radial direction.

4. The high- and low-pressure rotor with a common bearing cavity according to claim 1, characterized in that: Axial drainage holes three and four for guiding the lubricating oil to flow in are respectively provided at the axial ends of the center pull rod (210), and radial drainage holes four for guiding the lubricating oil to flow to the third bearing (340) and radial drainage holes five for guiding the lubricating oil to flow to the fourth bearing (360) are radially provided on the center pull rod (210).

5. The high- and low-pressure rotor with a common bearing cavity according to any one of claims 1 to 4, characterized in that: The first bearing (320) is a ball bearing for bearing the axial force and radial force of the low-pressure rotor (100), and the second bearing (330) is a roller bearing for bearing the radial force of the low-pressure rotor (100); and / or The first bearing (320) and the sixth bearing (380) are elastic supports, and the second bearing (330) and the fifth bearing (370) are rigid supports.

6. The high- and low-pressure rotor with a common bearing cavity according to any one of claims 1 to 4, characterized in that: The third bearing (340) and the fourth bearing (360) are elastic supports.

7. A turbofan engine, characterized in that: A high- and low-pressure rotor comprising a bearing common cavity as described in any one of claims 1-6.

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