High-low pressure rotor with bearing sharing cavity and turbofan engine

Abstract

The invention discloses a high-low pressure rotor with a bearing sharing a cavity and a turbofan engine, which comprise a low pressure rotor, a high pressure rotor, a supporting assembly, a first lubricating oil nozzle and a second lubricating oil nozzle, the supporting assembly comprises a front bearing seat provided with a front bearing cavity, a first bearing which is arranged in the front bearing cavity and supports the low-pressure rotor, a second bearing which is arranged in the front bearing cavity and supports the low-pressure rotor, a third bearing which is arranged in the front bearing cavity and supports the high-pressure rotor, and a rear bearing seat provided with a rear bearing cavity. The fourth bearing is arranged in the rear bearing cavity and used for supporting the high-pressure rotor; the fifth bearing is arranged in the rear bearing cavity and used for supporting the low-pressure rotor; the sixth bearing is arranged in the rear bearing cavity and used for supporting the low-pressure rotor; compared with the prior art, the motor has the characteristics of few parts, simple structure, compact axial size, small vibration and high reliability, is convenient for controlling the weight of an engine and reducing the cost of the engine, and is suitable for wide popularization and application.

Description

Technical Field

[0001] The present invention relates to the technical field of engine rotor structure layout, in particular, 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 a common bearing cavity. Background Art

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

[0003] At present, the layouts of high-pressure and low-pressure rotors in the world's mainstream small and medium-thrust turbofan engines are different, such as: 1) Pratt & Whitney's PW545 engine, whose high-pressure rotor adopts 1-0-1 support form, including 2A+1C combined compressor and 1-stage axial flow high-pressure turbine, and the low-pressure rotor adopts 0-2-1 support form, including 1-stage fan + 1-stage intermediate pressure compressor and 3-stage low-pressure turbine; 2) Williams' FJ44 engine, whose high-pressure rotor adopts 1-0-1 support form, including 1-stage centrifugal compressor and 1-stage axial high-pressure turbine, and whose low-pressure rotor adopts 0-3-0 support form, including 1-stage fan + 3-stage intermediate-pressure compressor and 2-stage low-pressure turbine; 3) The HF120 engine jointly developed by GE and Honda has a high-pressure rotor with a 1-stage centrifugal compressor and a 1-stage axial-flow high-pressure turbine, and a low-pressure rotor with a 1-stage fan + 2-stage intermediate-pressure compressor and a 2-stage low-pressure turbine.

[0004] The advantages of the rotor layout of the above-mentioned three types of engines are that the high-pressure turbine has a simple structure and a compact layout, and the multi-stage layout of the low-pressure rotor is beneficial to improving the engine's compression ratio. However, the disadvantages are that the low-pressure rotor has a large number of wheel stages, the rotor structure is complex, and the number of rotor load-bearing structures is large, and the corresponding number of lubricating oil circuits and sealed air induction circuits is large, resulting in a large number of engine parts, which is not conducive to the engine's weight reduction design, cost reduction and reliability improvement. Summary of the invention

[0005] The present invention provides a high- and low-pressure rotor and a turbofan engine with a common bearing cavity, so as to solve the technical problems of the existing turbofan engine having a complex rotor layout structure, a large number of parts, being unfavorable for engine weight reduction design, and having low reliability.

[0006] According to one aspect of the present invention, a high- and low-pressure rotor with a common bearing cavity is provided, comprising 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 arranged concentrically, the support assembly comprises a front bearing seat with a front bearing cavity, a first bearing arranged in the front bearing cavity and supporting the low-pressure rotor, a second bearing arranged in the front bearing cavity and supporting the low-pressure rotor, a third bearing arranged in the front bearing cavity and supporting the high-pressure rotor, a rear bearing seat with a rear bearing cavity, a fourth bearing arranged in the rear bearing cavity and supporting the high-pressure rotor, a fifth bearing arranged in the rear bearing cavity and supporting the low-pressure rotor, and a sixth bearing arranged in the rear bearing cavity and supporting the low-pressure rotor, the first lubricating oil nozzle is arranged in the front bearing cavity for jet lubrication of the second bearing and under-ring lubrication of the first bearing and the third bearing, and the second lubricating oil nozzle is arranged in the rear bearing cavity for under-ring lubrication of the fourth bearing, the fifth bearing and the sixth bearing.

[0007] As a further improvement of the above technical solution: Furthermore, the low-pressure rotor includes a low-pressure long shaft arranged concentrically 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 arranged on the low-pressure short shaft.

[0008] Furthermore, the low-pressure long shaft is provided with an axial drainage hole one along the axial direction for guiding the axial inflow of lubricating oil, and the low-pressure long shaft is provided with a radial drainage hole one along the radial direction for guiding the lubricating oil to flow toward the first bearing.

[0009] Furthermore, the low-pressure short shaft is axially provided with axial drainage hole 2 for guiding the lubricating oil to flow in, and the low-pressure short shaft is radially provided with radial drainage hole 2 for guiding the lubricating oil to flow to the fifth bearing and radial drainage hole 3 for guiding the lubricating oil to flow to the sixth bearing.

[0010] Furthermore, the high-pressure rotor includes a center tie rod sleeved outside the low-pressure long shaft, a combined compressor fixed on the center tie rod, and a two-stage axial flow high-pressure turbine fixed on the center tie rod. The combined compressor includes a three-stage axial flow compressor and a one-stage centrifugal compressor.

[0011] Furthermore, the axial flow fan is provided with a sealing ring rotating body for dynamically cooperating with the graphite on the front bearing seat to seal the front end of the front bearing cavity, and the three-stage axial flow compressor is provided with stepped comb teeth for cooperating with the engine stator to seal the rear end of the front bearing cavity.

[0012] Furthermore, axial ends of the center pull rod are respectively provided with axial drainage hole three and axial drainage hole four for guiding the inflow of lubricating oil, and the center pull rod is radially provided with radial drainage hole four for guiding the lubricating oil to flow to the third bearing and radial drainage hole five for guiding the lubricating oil to flow to the fourth bearing.

[0013] 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 bearings, and the second bearing and the fifth bearing are rigid bearings.

[0014] Furthermore, the third bearing and the fourth bearing are elastically supported.

[0015] According to another aspect of the present invention, there is also provided a turbofan engine, which includes the high- and low-pressure rotors with a common bearing cavity as described above.

[0016] The present invention has the following beneficial effects: The high- and low-pressure rotors of the present invention share a common bearing cavity, and the support assembly realizes a 0-4-0 support form for the low-pressure rotor through the front bearing seat, the first bearing, the second bearing, the rear bearing seat, the fifth bearing and the sixth bearing, so as to realize a front and rear double-pivot layout, which can greatly improve the structural stability of the low-pressure rotor; the 1-0-1 support form for the high-pressure rotor is realized through the front bearing seat, the third bearing, the rear bearing seat 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. The number of bearing cavities is reduced by the common bearing cavity layout, and the number of lubricating oil pipelines, air pipelines, sealing structures and load-bearing structures is correspondingly reduced, which is beneficial to the engine weight reduction design and improves the engine reliability. In addition, the common bearing cavity layout can greatly shorten the axial length of the engine, making the engine structure compact. The space utilization rate is high, which is convenient for engine size control, and can also reduce the bleed air used for bearing cavity sealing, thereby reducing the performance loss caused by bleed air; the lubrication of all bearings is achieved through the joint action of the first lubricating oil nozzle and the second lubricating oil nozzle, and except for the second bearing with a smaller radial size which is jet lubricated, the other bearings are all under-ring lubricated, so as to improve the utilization rate of the lubricating oil, reduce the lubricating oil flow, reduce the oil circuit size, and facilitate the small and lightweight design of the relevant lubricating oil pump; this scheme adopts a structural layout method such as a low-pressure rotor with 0-4-0 support, a high-pressure rotor with 1-0-1 support, and under-ring lubrication of the bearings under the common cavity of the high and low pressure rotor bearings. Compared with the prior art, this scheme has the characteristics of a small number of parts, a simple structure, a compact axial size and high reliability, which is convenient for engine weight control and reducing engine cost, improves engine reliability, has strong practicality, and is suitable for wide promotion and application.

[0017] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 2 is a schematic structural diagram of a high-pressure and low-pressure rotor with a common bearing cavity according to a preferred embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of the front end structure of the high and low pressure rotors with a common bearing cavity is shown; Figure 3 yes Figure 1 A schematic diagram of the rear end structure of the high and low pressure rotors with a common bearing cavity is shown; Figure 4 yes Figure 2 The rear end structure schematic diagram of the high and low pressure rotors with a common bearing cavity is shown.

[0019] Legend: 100, low-pressure rotor; 110, low-pressure long shaft; 120, axial-flow fan; 130, low-pressure short shaft; 140, two-stage axial-flow low-pressure turbine; 200, high-pressure rotor; 210, center tie rod; 220, combined compressor; 230, two-stage axial-flow high-pressure turbine; 310, front bearing seat; 311, front bearing cavity; 320, first bearing; 330, second bearing; 340, third bearing; 350, rear bearing seat; 351, rear bearing cavity; 360, fourth bearing; 370, fifth bearing; 380, sixth bearing; 400, second lubricating oil nozzle; 500, sealing ring rotor one; 600, stepped comb teeth; 700, sealing ring rotor two; 800, sealing ring rotor three. DETAILED DESCRIPTION

[0020] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0021] like Figure 1-Figure 3As shown, the high- and low-pressure rotors with a common bearing 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) and a second lubricating oil nozzle 400. The low-pressure rotor 100 and the high-pressure rotor 200 are arranged concentrically, and the support assembly includes a front bearing seat 310 with 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, and a rear bearing 351 with a rear bearing cavity 351. The bearing seat 350, the fourth bearing 360 arranged in the rear bearing cavity 351 and supporting the high-pressure rotor 200, the fifth bearing 370 arranged in the rear bearing cavity 351 and supporting the low-pressure rotor 100, and the sixth bearing 380 arranged in the rear bearing cavity 351 and supporting the low-pressure rotor 100, the first lubricating oil nozzle arranged in the front bearing cavity 311, used 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 arranged in the rear bearing cavity 351, used for under-ring lubrication of the fourth bearing 360, the fifth bearing 370 and the sixth bearing 380.

[0022] like Figure 1-Figure 3As shown, specifically, the high-pressure and low-pressure rotors with a common bearing cavity of the present invention, the support assembly realizes a 0-4-0 support form for the low-pressure rotor 100 through the front bearing seat 310, the first bearing 320, the second bearing 330, the rear bearing seat 350, the fifth bearing 370 and the sixth bearing 380, so as to realize a front and rear double-pivot layout, which can greatly improve the structural stability of the low-pressure rotor and reduce vibration; the front bearing seat 310, the third bearing 340, the rear bearing seat 350 and the fourth bearing 360 realize a 1-0-1 support form for the high-pressure rotor 200 The support form can ensure that the high-pressure rotor 200 avoids the critical speed in a wide speed range, avoids the limitation of engine use due to vibration problems, and facilitates the expansion of the subsequent working speed range; the first bearing 320, the second bearing 330 and the third bearing 340 are arranged together in the front bearing cavity 311, and the fourth bearing 360, the fifth bearing 370 and the sixth bearing 380 are arranged together in the rear bearing cavity 351. The number of bearing cavities is reduced by the common cavity layout of the bearings, and the number of lubricating oil pipelines, air pipelines, and seals is correspondingly reduced. The number of structures and load-bearing structures is conducive to the weight reduction design of the engine and improves the engine reliability. In addition, the common cavity layout of the bearings can greatly shorten the axial length of the engine, making the engine structure compact and the space utilization rate high, which is convenient for engine size control, and can also reduce the bleed air used for sealing the bearing cavity, thereby reducing the performance loss caused by the bleed air; the first lubricating oil nozzle and the second lubricating oil nozzle 400 work together to achieve lubrication of all bearings, and except for the second bearing 330 with a smaller radial size, which is jet lubricated, the other bearings are all under-ring lubricated, so as to improve the utilization rate of the lubricating oil, reduce the lubricating oil flow, reduce the oil circuit size, and facilitate the small and lightweight design of the related lubricating oil pump; this scheme adopts the structural layout mode of the low-pressure rotor 100 supported by 0-4-0, the high-pressure rotor 200 supported by 1-0-1, and the bearing under-ring lubrication under the common cavity of the high and low pressure rotor bearings. Compared with the prior art, this scheme has the characteristics of a small number of parts, a simple structure, a compact axial size, a small vibration and a high reliability, which is convenient for engine weight control and reducing engine cost, has strong practicality, and is suitable for wide promotion and application.

[0023] It should be understood that under-the-ring lubrication refers to the lubricating oil being sprayed from the lubricating oil nozzle into the internal oil supply channel of the corresponding rotating shaft (such as the low-pressure long shaft 110, the low-pressure short shaft 130 and the center tie rod 210), and then entering the roller through the inner ring of the bearing to provide heat dissipation and lubrication for the bearing. Compared with the method of spraying the lubricating oil to the bearing rollers, this oil supply method has a high lubricating oil utilization rate of more than 95%. Due to the high efficiency of the under-the-ring lubrication method, under the condition of the same heat dissipation demand, the demand for lubricating oil is less, which can correspondingly reduce the lubricating oil flow rate and the size of the oil circuit. At the same time, the capacity requirements of the lubricating oil pump are also lower, which facilitates the small and lightweight design of the lubricating oil pump.

[0024] It should be understood that the high- and low-pressure rotors with a common bearing cavity are core components of the engine, and therefore their beneficial effects are mainly reflected in optimizing the performance of the engine.

[0025] It should be understood that the lubricating oil pipeline is used to lubricate the bearings in the bearing cavity, the air pipeline is used to seal and bleed air into 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, thereby greatly reducing the number of parts, facilitating engine weight control, reducing engine costs and improving engine reliability.

[0026] like Figure 1 As shown, in this embodiment, the low-pressure rotor 100 includes 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. Specifically, the wheel of the axial-flow fan 120 is fixed to the low-pressure long shaft 110 through a shaft 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 arranged concentrically, connected and fixed by a shaft nut, and the spline is used to transmit torque; the two-stage axial-flow low-pressure turbine 140 is 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 the arc end teeth.

[0027] like Figure 2 As shown, in this embodiment, the low-pressure long shaft 110 is provided with an axial drainage hole 1 for guiding the axial inflow of lubricating oil, and the low-pressure long shaft 110 is provided with a radial drainage hole 1 for guiding the lubricating oil to flow toward the first bearing 320 along the radial direction. Specifically, after the first lubricating oil nozzle sprays lubricating oil in the front bearing cavity 311, the lubricating oil flows into the low-pressure long shaft 110 along the axial direction through the axial drainage hole 1, and then flows toward the first bearing 320 along the radial direction through the radial drainage hole 1, so as to realize the under-ring lubrication of the first bearing 320.

[0028] It should be understood that since the radial dimension of the second bearing 330 is relatively small, it is difficult to open the drainage hole thereof, and therefore, the lubrication method of the second bearing 330 is jet lubrication.

[0029] like Figure 3As shown, in this embodiment, 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. 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 along the axial direction through the axial drainage hole 2, and then flows to the fifth bearing 370 along the radial direction through the radial drainage hole 2, and flows 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.

[0030] like Figure 1 As shown, in this embodiment, the high-pressure rotor 200 includes a center tie rod 210 sleeved outside the low-pressure long shaft 110, a combined compressor 220 fixed on the center tie rod 210, and a two-stage axial flow high-pressure turbine 230 fixed on the center tie rod 210, and the combined compressor 220 includes a three-stage axial flow compressor and a one-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, improve 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.

[0031] It should be understood that A refers to an axial compressor and C refers to a centrifugal compressor.

[0032] like Figure 4As shown, in this embodiment, a sealing ring rotor 500 is arranged on the axial flow fan 120 for dynamically cooperating with the graphite on the front bearing seat 310 to seal the front end of the front bearing cavity 311, and a stepped comb tooth 600 is arranged on the three-stage axial flow compressor for cooperating with the engine stator to seal the rear end of the front bearing cavity 311. Specifically, the front end of the front bearing cavity 311 is sealed by dynamically cooperating with the sealing ring rotor 500 and the graphite on the front bearing seat 310 to realize a floating ring graphite seal. The floating ring graphite seal can float radially according to the vibration of the rotor to ensure that the sealing gap of the rotor remains unchanged in all states. At the same time, high-pressure sealing gas is introduced through the air bleed channel to ensure the sealing effect. The sealing structure is simple and reliable, and there will be no permanent enlargement of the sealing gap between the rotor and the stator due to wear. 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, so The stepped grate teeth 600 cooperate with the engine stator to seal the rear end of the front bearing cavity 311. The stepped grate teeth 600 can achieve multi-grate sealing (double-grate sealing in this embodiment). The high-pressure gas sealing can be introduced between two adjacent grate teeth by using the disc cavity gap of the combined compressor 220. Only two holes need to be drilled on the shaft neck of the compressor disc to achieve the bleed air sealing. The structure is simple and reliable. The stepped grate teeth 600 and the high-pressure gas sealing can greatly improve the sealing ability, and to a large extent avoid the reduction of the sealing effect caused by the increase of the bleed air sealing gap due to the scraping of the grate teeth. Optionally, the stepped grate teeth 600 are arranged on the shaft neck of the first-stage axial flow compressor, and the shaft neck of the first-stage axial flow compressor is provided with a bleed air sealing hole for introducing the compressed gas between the two grate teeth.

[0033] It should be understood that the combined sealing form of the floating ring graphite seal and the stepped comb teeth 600 not only improves the sealing performance but also increases the service life of the seal, thereby improving the reliability of the engine.

[0034] like Figure 3 As shown, in this embodiment, a sealing ring rotating body 2 700 is arranged on the high-pressure rotor 200 for dynamically cooperating with the graphite on the rear bearing seat 350 to seal the front end of the rear bearing cavity 351, and a sealing ring rotating body 3 800 is arranged on the low-pressure rotor 100 for dynamically cooperating with the graphite on the rear bearing seat 350 to seal the rear end of the rear bearing cavity 351. The floating ring graphite seal at the front and rear ends of the rear bearing cavity 351 is realized by the sealing ring rotating body 2 700 and the sealing ring rotating body 3 800. The floating ring graphite seal can float radially according to the vibration of the rotor to ensure that the sealing gap of the rotor remains unchanged in all states. At the same time, high-pressure sealing gas is introduced through the air duct to ensure the sealing effect. The sealing structure is simple and reliable, and there will be no permanent increase in the sealing gap between the rotor and the stator due to wear. It has the advantages of good sealing effect and long service life.

[0035] It should be understood that the engine stator component that cooperates with the stepped comb teeth 600 to seal is located outside the front bearing seat 310.

[0036] like Figure 2 and Figure 3 As shown, in this embodiment, the axial ends of the center rod 210 are respectively provided with an axial drainage hole 3 and an axial drainage hole 4 for guiding the lubricating oil to flow in, and the center rod 210 is radially provided with a radial drainage hole 4 for guiding the lubricating oil to flow to the third bearing 340 and a radial drainage hole 5 for guiding the lubricating oil to flow to the fourth bearing 360. Specifically, after the first lubricating oil nozzle sprays lubricating oil in the front bearing cavity 311, the lubricating oil enters the center rod 210 through the axial drainage hole 3 in the axial direction, and then flows to the third bearing 340 through the radial drainage hole 4 in the radial direction, so as to achieve the 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 center rod 210 through the axial drainage hole 4 in the axial direction, and then flows to the fourth bearing 360 through the radial drainage hole 5 in the radial direction, so as to achieve the under-ring lubrication of the fourth bearing 360.

[0037] 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, and 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 the radial force of the low-pressure rotor 100 is borne by the second bearing 330, so that the double-support point layout of the first bearing 320 and the second bearing 330 can greatly improve the ability of the low-pressure long shaft 110 to resist the bending moment caused by the wheel of the axial flow fan 120, reduce the deflection of the low-pressure long shaft 110, and improve the working stability of the low-pressure rotor.

[0038] like Figure 1 As 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. 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 by the high-speed operation of the two-stage axial flow low-pressure turbine. The double-pivot layout of the fifth bearing 370 and the sixth bearing 380 can greatly improve the ability of the low-pressure short shaft 130 to resist the bending moment brought by the two-stage axial flow low-pressure turbine, reduce the deflection of the low-pressure short shaft 130, and improve the working stability of the low-pressure rotor.

[0039] 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.

[0040] 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 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.

[0041] 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.

[0042] 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) is arranged in the bearing cavity (351) and supports the high-pressure rotor (200), a fifth bearing (370) is arranged in the rear bearing cavity (351) and supports the low-pressure rotor (100), and a sixth bearing (380) is arranged in the rear bearing cavity (351) and supports the low-pressure rotor (100). A first lubricating oil nozzle is arranged in the front bearing cavity (311) and is used for jet lubrication of the second bearing (330) and under-ring lubrication of the first bearing (320) and the third bearing (340). A second lubricating oil nozzle (400) is arranged in the rear bearing cavity (351) and is used for under-ring lubrication of the fourth bearing (360), the fifth bearing (370) and the sixth bearing (380).

2. The high- and low-pressure rotor with a common bearing cavity according to claim 1, characterized in that: 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).

3. The high- and low-pressure rotor with a common bearing cavity according to claim 2, 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.

4. The high- and low-pressure rotor with a common bearing cavity according to claim 2, 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.

5. The high- and low-pressure rotor with a common bearing cavity according to claim 2, characterized in that: The high-pressure rotor (200) includes a center tie rod (210) sleeved outside the low-pressure long shaft (110), a combined compressor (220) fixed on the center tie rod (210), and a two-stage axial-flow high-pressure turbine (230) fixed on the center tie rod (210), wherein the combined compressor (220) includes a three-stage axial-flow compressor and a one-stage centrifugal compressor.

6. The high- and low-pressure rotor with a common bearing cavity according to claim 5, characterized in that: 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).

7. The high- and low-pressure rotor with a common bearing cavity according to claim 5, 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).

8. The high- and low-pressure rotor with a common bearing cavity according to any one of claims 1 to 7, 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.

9. The high- and low-pressure rotor with a common bearing cavity according to any one of claims 1 to 7, characterized in that: The third bearing (340) and the fourth bearing (360) are elastic supports.

10. A turbofan engine, characterized in that: A high- and low-pressure rotor comprising a bearing common cavity as described in any one of claims 1-9.

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