Squeeze film damper, planetary reduction gear and geared turbofan engine

Abstract

An squeeze oil film damper, planetary reducer and gear transmission turbofan engine for improving the situation of load imbalance between planetary gears; the squeeze oil film damper comprises a shaft member and a hole member, the shaft member and the hole member cooperate to form an annular gap, the squeeze oil film damper further comprises an oil film bushing and a sealing ring arranged in the annular gap, the oil film bushing and the sealing ring define an oil film gap; the radially outer ring of the oil film bushing cooperates with the radially inner ring of the hole member to define the radial dimension of the oil film gap; the sealing ring defines the axial dimension of the oil film gap, at least two of the oil film gaps are distributed along the axial direction for axial sealing; the oil film gap is used for internal oil filling to form an oil film layer for radial floating support, the oil film bushing is radially deformable to expand the radial deformable dimension of the oil film layer.

Description

TECHNICAL FIELD

[0001] The present application relates to a damper, in particular to an extrusion oil film damper, a planetary reducer and a geared turbofan engine. BACKGROUND

[0002] In the field of aviation, a geared turbofan engine (GTF) installs a set of appropriate gear reducers (fan drive gearbox) between the low-pressure rotor composed of a low-pressure compressor and a low-pressure turbine and a fan rotor, so that the fan rotor works at a low speed and the low-pressure rotor works at a high speed, thereby reducing the number of compressor stages and reducing weight and improving efficiency. As a component connecting the fan rotor and the low-pressure rotor in the geared turbofan engine, the fan drive gearbox has the characteristics of large power transmission, high transmission efficiency and long service life.

[0003] In order to transmit the maximum power in the limited volume of the gearbox, the fan drive gearbox often adopts a five-way split herringbone gear planetary transmission structure, which is an advanced gear transmission mechanism with the characteristics of compact structure, small volume, large carrying capacity, large transmission range and high efficiency. However, in actual work, due to gear machining and installation errors and various random disturbance factors, the planetary gear train may resonate and deform, and the load among the planetary gears may be unbalanced, affecting the stability and accuracy of transmission, and even causing damage to the entire transmission system. Controlling the load sharing coefficient at a low level can maximize the power transmission capacity of the fan drive gearbox, so a load sharing structure is needed, which can automatically achieve uniform load distribution among the planetary gears when the planetary gears are unevenly loaded, to reduce impact, reduce noise and prolong the service life of the gearbox. SUMMARY

[0004] An object of the present application is to provide an extrusion oil film damper for suppressing vibration and impact.

[0005] According to an embodiment of the present application, the extrusion oil film damper comprises a shaft member and a hole member, which cooperate to form an annular gap, and further comprises an oil film bushing arranged in the annular gap and a sealing ring, which define an oil film gap; a radially outer ring of the oil film bushing and a radially inner ring of the hole member cooperate to define a radial dimension of the oil film gap; the sealing ring defines an axial dimension of the oil film gap, and at least two oil film gaps are distributed along the axial direction for axial sealing; the oil film gap is used to internally fill oil to form an oil film layer for radial floating support, and the oil film bushing is radially deformable to expand the radial deformable dimension of the oil film layer.

[0006] In one or more embodiments, the oil film bushing is circumferentially uniformly distributed with oil supply holes, which in the axial direction communicate with the middle position of the oil film gap.

[0007] Another object of the present application is to provide a planetary reducer, which includes the above-mentioned squeeze oil film damper, for improving the situation of load imbalance among planetary gears.

[0008] According to embodiments of the present application, the planetary reducer includes a first squeeze oil film damper, a planetary gear shaft, and a planet carrier, the first squeeze oil film damper being the above-mentioned squeeze oil film damper, wherein the shaft member is the planetary gear shaft, the hole member is provided by the planet carrier, and the planetary gear shaft is radially floatingly supported on the planet carrier.

[0009] In one or more embodiments, the oil film bushing is provided with a rim on the axial outside of the planet carrier and is elastically connected to the planet carrier through the rim; the rim has an elastic bending portion and a platform portion, the elastic bending portion is circumferentially uniformly distributed with a plurality of elastic bending arms, the oil film bushing is connected to the platform portion through the plurality of elastic bending arms, and the platform portion is fixedly connected to the planet carrier.

[0010] In one or more embodiments, the planetary reducer further includes a planetary gear bearing, a planetary gear core, and an oil pipe, oil flows into an outer cavity defined by the planetary gear core and the planetary gear through an inner cavity of the planetary gear core and the oil pipe, and is then distributed to the planetary gear bearing and the squeeze oil film damper.

[0011] In one or more embodiments, a radially inner ring of the planetary gear core side wall defines a cylinder-shaped inner cavity, and the oil pipe communicates with an opening on one axial side of the inner cavity; a radially outer ring of the planetary gear core side wall and a radially inner ring of the planetary gear side wall define an annular outer cavity, the planetary gear core side wall is circumferentially uniformly distributed with a plurality of radial through holes to communicate the inner cavity and the outer cavity; the planetary gear side wall is circumferentially uniformly distributed with a plurality of radial bearing oil supply holes to communicate the outer cavity and the planetary gear bearing; the oil film bushing is sleeved on the planetary gear, and a radially outer ring of the planetary gear side wall is provided with an annular oil groove at the oil film bushing to communicate the outer cavity and the oil film bushing.

[0012] In one or more embodiments, the planetary reducer further includes a planetary gear and a planetary gear bearing, and a radially inner ring of the planetary gear provides an outer raceway of the planetary gear bearing.

[0013] In one or more embodiments, the planetary reducer further includes a fixedly arranged end cover, the end cover has an anti-rotation boss, an axial end of the planetary gear shaft has an anti-rotation hole, and the anti-rotation boss of the end cover is inserted into the anti-rotation hole to prevent the planetary gear shaft from rotating.

[0014] In one or more embodiments, the planetary reducer further comprises a planetary gear shaft bearing, a radially inner ring of the planetary gear shaft bearing having an anti-rotation boss, a radially outer ring of the planetary gear shaft sidewall having an anti-rotation groove, the anti-rotation boss of the radially inner ring being embedded into the anti-rotation groove to prevent the radially inner ring from rotating relative to the planetary gear shaft.

[0015] In one or more embodiments, the planetary reducer further comprises a second squeeze oil film damper and a planetary gear shaft bearing, the second squeeze oil film damper being the squeeze oil film damper as described above, wherein the shaft member is the planetary gear shaft, and the hole member is provided by the planetary gear shaft bearing, the planetary gear shaft bearing being radially floatingly supported on the planetary gear shaft.

[0016] It is still another object of the present application to provide a geared turbofan engine comprising the planetary reducer as described above.

[0017] According to embodiments of the present application, the geared turbofan engine comprises a low pressure rotor, a fan rotor, and a planetary reducer, the low pressure rotor and the fan rotor being connected through the planetary reducer, the planetary reducer being the planetary reducer as described above.

[0018] Embodiments of the present application have at least one of the following beneficial effects:

[0019] 1. The oil film bushing is radially deformable, which expands the radially deformable size of the oil film layer and ensures the effect of the squeeze oil film damper in suppressing vibration and impact.

[0020] 2. The planetary gear shaft of the planetary reducer is radially floatingly supported on the planet carrier, and the uniform distribution of load among the planetary gears is achieved by means of the elastic deformation of the oil film layer.

[0021] 3. By providing the radially deformable oil film bushing between the planetary gear shaft and the planet carrier, the elastic deformation amount of the oil film layer of the squeeze oil film damper is ensured to meet the uniform load requirement among the planetary gears of the planetary reducer.

[0022] 4. By providing the oil to be supplied to the planetary gear bearing and the squeeze oil film damper through the planetary gear shaft, the oil supply difficulty is reduced, and the oil utilization rate is improved.

[0023] 5. The gear-bearing integrated design is adopted, the inner ring of the planetary gear is the outer raceway of the planetary gear bearing, the planetary gear support structure is simplified, and the radial size of the planetary reducer is reduced.

[0024] 6. The anti-rotation structure is provided on the planetary gear shaft, the end cover, and the planetary gear bearing to prevent abnormal rotation. BRIEF DESCRIPTION OF DRAWINGS

[0025] The above and other features, properties, and advantages of the present application will become more apparent by reference to the following description of the embodiments wherein:

[0026] Figure 1 Structure diagram of the squeeze film damper;

[0027] Figure 2 Structure diagram of the seal ring;

[0028] Figure 3 Structure diagram of the planetary reducer;

[0029] Figure 4 Oil flow direction diagram of the planetary reducer.

[0030] Reference signs:

[0031] 1 - squeeze film damper; 2 - shaft; 3 - hole; 5 - seal ring; 6 - oil film gap; 7 - oil supply hole; 8 - mounting groove; 9 - opening gap

[0032] 4 - oil film bushing; 35 - rim; 36 - elastic bending part; 37 - platform part; 38 - cutout; 39 - elastic support arm

[0033] 10 - planetary reducer; 11 - first squeeze film damper

[0034] 13 - planet carrier; 14 - mounting hole

[0035] 12 - planet shaft; 15 - first shaft end; 40 - second shaft end; 22 - anti-rotation hole; 24 - anti-rotation groove; 27 - outer cavity; 30 - bearing oil supply hole; 33 - annular oil groove; 34 - oil groove oil supply hole

[0036] 16 - planet

[0037] 17 - planet bearing; 23 - second anti-rotation boss; 31 - oil passage

[0038] 18 - planet shaft core; 26 - inner cavity; 28 - opening; 29 - hole; 32 - seal ring

[0039] 19 - oil pipe

[0040] 20 - end cover; 21 - first anti-rotation boss

[0041] 25 - bearing retainer DETAILED DESCRIPTION

[0042] The directional terms such as “radial,” “axial,” “circumferential,” “inner ring,” and “outer ring” refer to shaft 2 and hole 3. The terms “first” and “second” are used interchangeably to distinguish one component from another and are not intended to indicate that each component must be located in the position shown in the figure in each embodiment.

[0043] Example 1

[0044] Figures 1 to 2 Example 1 is shown. (As...) Figure 1 As shown, the extrusion oil film damper 1 includes a shaft 2, a bore 3, an oil film bushing 4, and a sealing ring 5. The shaft 2 and the bore 3 cooperate to form an annular gap. The oil film bushing 4 and the sealing ring 5 are disposed in this annular gap and define an oil film gap 6. Specifically, the oil film bushing 4 is sleeved on the radial outer ring of the shaft 2, and the radial outer ring of the oil film bushing 4 cooperates with the radial inner ring of the bore 3 to define the radial dimension of the oil film gap 6. The sealing ring 5 defines the axial dimension of the oil film gap 6, and at least two are distributed axially in the oil film gap 6 for axial sealing. The dimension of the oil film gap 6 is determined according to the usage requirements of the extrusion oil film damper 1. The number of sealing rings 5 ​​depends on the number of oil film cavities in the oil film gap 6. Figure 1 The illustrated oil film gap 6 is provided with an oil film cavity, i.e., the complete oil film gap 6 itself, with a sealing ring 5 arranged at each of the axial ends of the oil film gap 6 to seal the oil film gap 6 axially. In another embodiment, the oil film gap 6 is divided into multiple oil film cavities axially. In this case, a sealing ring 5 is also provided between the two sealing rings 5 ​​located at the two axial ends of the sealing oil film gap 6 to divide the oil film gap 6 into multiple oil film cavities.

[0045] The oil film gap 6 is used to internally fill with oil to form an oil film layer, thereby creating a radial floating support between the shaft 2 and the bore 3. Specifically, the oil passage connects to the oil film gap 6, and oil continuously flows into the oil film gap 6 through the oil passage. The suction effect of the oil film gap 6 on the oil, as well as the squeezing and shearing effect of the relative movement of the shaft 2 and the bore 3 on the oil, causes the oil to form an elastic oil film layer within the oil film gap 6, thus forming a radial floating support between the shaft 2 and the bore 3. When the shaft 2 is fixed and the bore 3 is allowed to move radially, the bore 3 floats radially on the shaft 2, and the oil film layer elastically deforms to absorb the vibration and impact of the bore 3; when the bore 3 is fixed and the shaft 2 is allowed to move radially, the shaft 2 floats radially within the bore of the bore 3, and the oil film layer elastically deforms to absorb the vibration and impact of the shaft 2.

[0046] The oil film bushing 4 is radially deformable to expand the radially deformable size of the oil film layer. Specifically, the oil film bushing 4 adopts a flexible structure and is radially deformable. The relative movement of the shaft 2 and the oil film bushing 4 thereon and the hole 3 continuously presses and shears the oil film layer to cause elastic deformation of the oil film layer, so that the shaft 2 can radially float when loaded, and the effect of the squeeze oil film damper 1 in suppressing vibration and impact is ensured. In addition, the oil film bushing 4 has a small radial size and is suitable for being arranged at a gap with limited size.

[0047] As shown in Figure 1 , the oil film bushing 4 is circumferentially uniformly provided with oil supply holes 7, which communicate with the middle position of the oil film gap 6 in the axial direction. Specifically, the oil supply holes 7 are circumferentially uniformly arranged on the oil film bushing 4, and the oil supply holes 7 are connected by an oil passage to supply oil to the oil film gap 6, so as to ensure that the oil film gap 6 can be uniformly supplied with oil at each circumferential position, and the oil supply holes 7 communicate with the middle position of the oil film gap 6 in the axial direction, so as to ensure that the oil film gap 6 can be sufficiently supplied with oil at both ends in the axial direction, and the number of the oil supply holes 7 is specifically six. In another or more embodiments, the number of the oil supply holes 7 can also be other numbers. In order to meet the full oil film state working of the squeeze oil film damper 1 and reduce the stiffness effect and cavitation effect of the squeeze oil film damper 1, the oil supply pressure needs to meet certain requirements, and the radial stiffness of the squeeze oil film damper 1 can also be changed by adjusting the oil supply pressure according to the use requirements.

[0048] As shown in Figure 1 , the sealing ring 5 is arranged in the annular mounting groove 8 of the oil film bushing 4, and the radially outer ring of the sealing ring 5 abuts against the radially inner ring of the hole 3 to seal. Figure 2 As shown in , the sealing ring 5 is provided with an open gap 9, so that the oil in the oil film layer in the oil film gap 6 can circulate and flow, and the heat generated by vibration and impact can be taken away. In this embodiment, the sealing ring 5 adopts a piston type sealing ring. In another or more embodiments, the sealing ring 5 adopts a sealing ring with other structures provided with an open gap.

[0049] Embodiment Two

[0050] Figures 3 to 4 Embodiment Two is shown. Embodiment Two uses the element numbers and part of the content of Embodiment One, wherein the same numbers are used to represent the same or similar elements, and the description of the same technical content is selectively omitted. The description of the omitted part can be referred to Embodiment One, and Embodiment Two will not be repeated here.

[0051] As shown in Figure 3 , the planetary reducer 10 includes a first squeeze oil film damper 11, a planetary wheel shaft 12, a planet carrier 13, a planetary wheel 16, a planetary wheel bearing 17, a planetary wheel shaft core 18, an oil pipe 19 and an end cover 20.

[0052] The first extrusion oil film damper 11 adopts the structure of the extrusion oil film damper described in Embodiment 1. The shaft 2 is a planetary gear shaft 12, and the hole 3 is provided by the planet carrier 13. Specifically, the two shaft ends of the planetary gear shaft 12, the first shaft end 15 and the second shaft end 40, respectively pass through the mounting holes 14 on the planet carrier 13 and are fitted with the mounting holes 14. The radial outer rings of the two shaft ends fit with the radial inner rings of the mounting holes 14 to form an annular gap. The oil film bushing 4 and the sealing ring 5 are disposed in the annular gap and define the oil film gap 6. The oil film bushing 4 is sleeved on the radial outer rings of the two shaft ends. The radial outer rings of the oil film bushing 4 fit with the radial inner rings of the mounting holes 14 to define the radial dimension of the oil film gap 6. The sealing ring 5 defines the axial dimension of the oil film gap 6. A sealing ring 5 is arranged at each end of the axial direction of the oil film gap 6 to seal the oil film gap 6 in the axial direction. The planetary carrier 13 is fixedly installed. The elastic oil film layer in the two oil film gaps 6 supports the first shaft end 15 and the second shaft end 40 respectively, allowing the planetary gear shaft 12 to move within a certain range in the radial direction within the mounting hole 14. The planetary gear shaft 12 is radially floating and supported by the planetary carrier 13.

[0053] like Figure 3 As shown, the oil film bushing 4 has an edge 35 on the axial outer side of the planetary carrier 13, and is elastically connected to the planetary carrier 13 through the edge 35. Specifically, the edge 35 has an elastic bending portion 36 and a platform portion 37. The elastic bending portion 36 is a rotating body structure with a radial cross-section of a U-shape. The opening of the U-shaped rotating body faces the axial outer side of the planetary carrier 13. The radial inner wall of the U-shaped rotating body is connected to the oil film bushing 4, and the radial outer wall of the U-shaped rotating body is connected to the platform portion 37. Multiple cuts 38 are evenly distributed in the circumferential direction of the U-shaped rotating body, dividing the elastic bending portion 36 into multiple elastic support arms 39. The oil film bushing 4 is connected to the platform portion 37 through the multiple elastic support arms 39. The platform portion 37 is in close contact with the axial outer side of the planetary carrier 13 on one side and is fixedly connected to the planetary carrier 13 by bolts. The U-shaped structure of the elastic support arm 39 allows it to deform elastically within a certain range, realizing the elastic connection between the oil film bushing 4 and the planetary carrier 13, thereby allowing the oil film bushing 4 to move radially following the planetary gear shaft 12.

[0054] When the planetary reducer 10 is in operation, oil continuously flows into the oil film gap 6 through the oil passage. The oil film gap 6 has a suction effect on the oil, and the planetary wheel shaft 12 radially floats in the mounting hole 14, which has a shearing and extruding effect on the oil. The elastic deformation of the oil film layer enables the planetary wheel shaft 12 to radially float in the mounting hole 14, and automatically realizes the uniform distribution of loads among the planetary wheels 16 when the loads on the planetary wheels 16 of the planetary reducer 10 are uneven, thereby reducing impact, suppressing vibration, reducing noise, and prolonging service life. The oil film bushing 4 has a flexible structure and is deformable in the radial direction, which expands the radial deformable size of the oil film layer. The relative movement of the planetary wheel shaft 12 and the oil film bushing 4 on the mounting hole 14 continuously extrudes and shears the oil film layer, which causes the oil film layer to elastically deform. When the planetary wheel shaft 12 and the oil film bushing 4 are loaded, they can radially float, which ensures the effect of the first extruded oil film damper 11 in suppressing vibration and impact, and ensures that the elastic deformation of the oil film layer can meet the requirements of the uniform distribution of loads among the planetary wheels 16. In addition, the oil film bushing 4 has a small radial size, which is suitable for being arranged between the planetary wheel shaft 12 and the planet carrier 13 with limited radial gap size. The edge 35 of the oil film bushing 4 protrudes in the axial direction of the planet carrier 13, which is suitable for the arrangement of the output shaft of the planetary reducer 10, and meets the limitation of the space for accommodating the edge 35 in the shaft cavity of the output shaft.

[0055] The end cover 20 is fixedly arranged on the planet carrier 13 by bolts, and has a small gap with the shaft shoulder of the first shaft end 15 on one side of the planetary wheel shaft 12, which realizes the axial positioning of the planetary wheel shaft 12. The planetary wheel shaft 12 is in a state of axial positioning and radial floating, and is only supported by the first shaft end 15 and the second shaft end 40 in the radial direction in the mounting hole 14 of the planet carrier 13, which eliminates the influence of friction and other factors on the first extruded oil film damper 11. The end cover 20 is provided with a first anti-rotation boss 21 with a rectangular cross section, which is an integral structure with the end cover 20. The first shaft end 15 on the side close to the end cover 20 of the planetary wheel shaft 12 is provided with an anti-rotation hole 22 with a rectangular cross section, which has a size suitable for the size of the first anti-rotation boss 21. The first anti-rotation boss 21 of the end cover 20 is inserted into the anti-rotation hole 22 at the first shaft end 15 of the planetary wheel shaft 12. The first anti-rotation boss 21 which is fixed and cannot rotate prevents the rotation of the planetary wheel shaft 12 by cooperating with the anti-rotation hole 22, thereby preventing the rotation of the planetary wheel shaft 12. In another or more embodiments, the cross sections of the first anti-rotation boss 21 and the anti-rotation hole 22 are other shapes that hinder relative rotation, such as a triangle, a hexagon, etc.

[0056] The planetary wheel bearing 17 adopts a gear-bearing integrated design, and the radial inner ring of the planetary wheel 16 provides an outer raceway of the planetary wheel bearing 17, which simplifies the support structure of the planetary wheel 16 and reduces the radial dimension of the planetary reducer 10. The planetary wheel bearing 17 specifically adopts a double-row roller bearing, and the radial inner ring of the planetary wheel 16 is the bearing outer ring raceway of the planetary wheel bearing 17. The planetary wheel bearing 17 is sleeved on the radial outer ring of the side wall of the planetary wheel shaft 12, and the radial outer ring of the side wall of the planetary wheel shaft 12 provides radial support for the planetary wheel bearing 17. The planetary wheel bearing 17 is also provided with a second anti-rotation boss 23, which is specifically arranged on the axial side wall of the radial inner ring of the planetary wheel bearing 17 and protrudes from the axial side wall of the radial inner ring of the planetary wheel bearing 17. The radial outer ring of the side wall of the planetary wheel shaft 12 is provided with an anti-rotation groove 24, which is specifically arranged at the shaft shoulder on the side of the first shaft end 15 away from the end cover 20. The second anti-rotation boss 23 of the planetary wheel bearing 17 is embedded in the anti-rotation groove 24, and the non-rotating anti-rotation groove 24 blocks the rotation of the inner ring of the planetary wheel bearing 17 relative to the planetary wheel shaft 12 through cooperation with the second anti-rotation boss 23, preventing the radial inner ring of the planetary wheel bearing 17 from rotating relative to the planetary wheel shaft 12. The shaft shoulder provided with the anti-rotation groove 24 also abuts against the axial side wall of the radial inner ring of the planetary wheel bearing 17, providing axial limiting for the planetary wheel bearing 17. At the second shaft end 40 of the planetary wheel shaft 12 away from the end cover 20, the planetary reducer 10 is also provided with a bearing retainer 25, which is sleeved on the second shaft end 40 and is provided with radial support by the second shaft end 40. In the axial direction, one side of the bearing retainer 25 abuts against the inner wall of the planet carrier 13, and the other side abuts against the axial side wall of the radial inner ring of the planetary wheel bearing 17, providing axial limiting for the planetary wheel bearing 17. At the same time, this side maintains a small gap with the shaft shoulder of the second shaft end 40 of the planetary wheel shaft 12, providing axial limiting for the planetary wheel shaft 12. In another or more embodiments, the planetary wheel bearing 17 adopts other structures of bearings.

[0057] As Figure 4As shown, oil flows into the outer cavity 27 defined by the planetary shaft 12 and the planetary shaft core 18 via the oil pipe 19 and the inner cavity 26 of the planetary shaft core 18. Specifically, the planetary shaft 12 is a hollow shaft, and the core thereof is provided with a cylindrical cavity. The planetary shaft core 18 is also a hollow shaft, and the core thereof is provided with a cylindrical inner cavity 26 defined by the radially inner circle of the side wall of the planetary shaft core 18, which is closed at one end and provided with an opening 28 at the other end, specifically, the end close to the end cover 20 is closed, and the end away from the end cover 20 is provided with the opening 28, and the oil pipe 19 is inserted into the opening 28 to communicate with the cylindrical inner cavity 26. The planetary shaft core 18 is arranged in the cylindrical cavity of the planetary shaft 12, and the planetary shaft core 18 and the planetary shaft 12 cooperatively define the outer cavity 27, specifically, the radially outer circle of the side wall of the planetary shaft core 18 and the radially inner circle of the side wall of the planetary shaft 12 define the annular outer cavity 27, and the side wall of the planetary shaft core 18 is further provided with O-rings 32 at both axial ends, which are arranged in the annular grooves of the side wall of the planetary shaft core 18, and the radially outer circle of the O-rings 32 abuts against the radially inner circle of the side wall of the planetary shaft 12 to seal the annular outer cavity 27 at both axial ends. The side wall of the planetary shaft core 18 is provided with holes 29 to communicate the annular outer cavity 27 with the cylindrical inner cavity 26, specifically, the holes 29 are radial through holes extending radially from the radially inner circle of the side wall of the planetary shaft core 18 to the radially outer circle of the side wall of the planetary shaft core 18, and penetrating the side wall of the planetary shaft core 18, and the holes 29 are circumferentially distributed on the side wall of the planetary shaft core 18 to make the oil in the cylindrical inner cavity 26 flow uniformly to each circumferential position of the annular outer cavity 27, and the circumferentially distributed holes 29 at the same axial position form a row, and the side wall of the planetary shaft core 18 is provided with multiple rows of circumferentially distributed holes 29 to make the oil in the cylindrical inner cavity 26 flow sufficiently to each axial position of the annular outer cavity 27. The oil flows into the cylindrical inner cavity 26 via the oil pipe 19 and the opening 28, and then flows into the annular outer cavity 27 via the holes 29 of the side wall of the planetary shaft core 18.

[0058] As Figure 4The oil in the annular outer cavity 27 is then supplied to the planetary bearing 17 and the first squeeze oil film damper 11. Specifically, the side wall of the planetary shaft 12 is provided with bearing oil supply holes 30, which are radial through holes extending from the radial inner end of the side wall of the planetary shaft 12 to the radial outer end of the side wall of the planetary shaft 12, penetrating the side wall of the planetary shaft 12, and connecting the annular outer cavity 27 and the oil passage 31 of the radial inner end of the planetary bearing 17. The bearing oil supply holes 30 are circumferentially distributed on the side wall of the planetary shaft 12, so that the oil in the annular outer cavity 27 flows uniformly to each circumferential position of the planetary bearing 17. The circumferentially distributed bearing oil supply holes 30 at the same axial position form a row, and the side wall of the planetary shaft 12 is provided with multiple rows of circumferentially distributed bearing oil supply holes 30 at different axial positions, which are adapted to the axial positions of the oil passage 31 of the planetary bearing 17. The oil in the annular outer cavity 27 flows to the oil passage 31 of the planetary bearing 17 via the bearing oil supply holes 30, and is supplied to the planetary bearing 17 in a radial direction. The radial outer end of the side wall of the planetary shaft 12 is provided with an annular oil groove 33 at the oil film bushing 4 to connect the annular outer cavity 27 and the oil film bushing 4. The radial outer end of the planetary shaft 12 is provided with an annular oil groove 33 at the axial position corresponding to the oil supply hole 7 of the oil film bushing 4. The annular oil groove 33 is connected to the oil supply hole 7 of the oil film bushing 4. The annular oil groove 33 allows the oil in the annular oil groove 33 to flow uniformly to the circumferentially distributed oil supply holes 7 of the oil film bushing 4. The annular outer cavity 27 is connected to the annular oil groove 33 at the first shaft end 15 and the second shaft end 40 via an oil groove supply hole 34. The oil in the annular outer cavity 27 flows to the annular oil groove 33 via the oil groove supply hole 34. The oil in the annular oil groove 33 then flows to the oil film gap 6 via the oil supply hole 7 and forms an oil film layer. The oil flows to the annular outer cavity 27 first, and then is supplied to the oil passage of the planetary bearing 17 and the first squeeze oil film damper 11, which improves the utilization of oil and reduces the difficulty of oil supply.

[0059] The radial stiffness of the first squeeze oil film damper 11 can be adjusted by adjusting the oil supply pressure, which can be used to optimize the vibration response of the planetary gear train and achieve better load sharing between the planetary gears 16.

[0060] Embodiment Three

[0061] Embodiment Three

[0062] The planetary reducer 10 further comprises a second squeeze oil film damper, which adopts the structure of the squeeze oil film damper described in Embodiment One, wherein the shaft member 2 is the planetary wheel shaft 12, the hole member 3 is provided by the planetary wheel bearing 17, specifically the hole defined by the radial inner ring of the planetary wheel bearing 17, the planetary wheel bearing 17 is radially floatingly supported on the planetary wheel shaft 12, the planetary wheel bearing 17 is allowed to float within a certain range in the radial direction on the side wall of the planetary wheel shaft 12, thereby enabling the planetary wheel 16 to float within a certain range in the radial direction, and when the planetary wheels 16 of the planetary reducer 10 are unevenly loaded, the load uniform distribution among the planetary wheels 16 is automatically realized, so as to reduce impact, suppress vibration, reduce noise, and prolong service life. The radially deformable oil film bushing 4 expands the radially deformable size of the oil film layer, ensures the vibration and impact suppression effect of the second squeeze oil film damper, and ensures that the elastic deformation amount of the oil film layer can meet the requirement of load uniform distribution of the planetary wheels 16.

[0063] Embodiment Four

[0064] A geared turbofan engine, which comprises a low-pressure rotor, a fan rotor and a planetary reducer, the low-pressure rotor and the fan rotor are connected through the planetary reducer, and the planetary reducer adopts the structure of the planetary reducer described in Embodiment Two or Embodiment Three.

[0065] Although the present application is disclosed with the above embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application.

Claims

1. A planetary gear reducer, characterized in that, The planetary reducer includes a first extrusion oil film damper composed of an extrusion oil film damper. The extrusion oil film damper includes a shaft and a bore, which mate to form an annular gap. The extrusion oil film damper also includes an oil film bushing and a sealing ring disposed in the annular gap. The oil film bushing and the sealing ring define the oil film gap. The radial outer ring of the oil film bushing mates with the radial inner ring of the bore to define the radial dimension of the oil film gap. The sealing ring defines the axial dimension of the oil film gap. At least two sealing rings are distributed axially in the oil film gap for axial sealing. The oil film gap is used to fill with oil to form an oil film layer for radial floating support. The oil film bushing has a flexible structure and is radially deformable to expand the radially deformable dimension of the oil film layer. The planetary reducer also includes a planetary gear shaft and a planetary carrier. For the first extrusion oil film damper, the shaft is the planetary gear shaft, the bore is provided by the planetary carrier, and the planetary gear shaft is radially floatingly supported on the planetary carrier. For the first extrusion oil film damper, the oil film bushing has an edge on the axial outer side of the planetary carrier and is elastically connected to the planetary carrier through the edge. The edge has an elastic bending portion and a platform portion. The elastic bending portion has a plurality of elastic bending arms evenly distributed circumferentially. The oil film bushing is connected to the platform portion through the plurality of elastic bending arms. The platform portion is fixedly connected to the planetary carrier.

2. The planetary reducer according to claim 1, characterized in that, For the aforementioned extrusion oil film damper, the oil film bushing has oil supply holes evenly distributed circumferentially, and in the axial direction, the oil supply holes are connected to the middle position of the oil film gap.

3. The planetary reducer according to claim 1, characterized in that, The planetary reducer also includes planetary gear bearings, planetary gear shafts, and oil pipes. Oil flows into the outer cavity defined by the planetary gear shaft and the planetary gear shaft through the oil pipes and the inner cavity of the planetary gear shaft, and is then distributed to the planetary gear bearings and the squeeze oil film damper.

4. The planetary reducer according to claim 3, characterized in that, The radial inner ring of the planetary gear shaft sidewall defines the cylindrical inner cavity, and the oil pipe connects to an opening on one axial side of the inner cavity; The outer radial ring of the planetary gear shaft core sidewall and the inner radial ring of the planetary gear shaft core sidewall define the annular outer cavity, and the planetary gear shaft core sidewall is circumferentially provided with a plurality of radial through holes to connect the inner cavity and the outer cavity; The planetary gear shaft sidewall has multiple radial bearing oil supply holes evenly distributed around its circumference to connect the outer cavity and the planetary gear bearing. The oil film bushing is fitted onto the planetary gear shaft, and the radial outer ring of the planetary gear shaft sidewall is provided with an annular oil groove at the oil film bushing to connect the outer cavity and the oil film bushing.

5. The planetary reducer according to claim 1, characterized in that, The planetary gear reducer also includes planetary gears and planetary gear bearings, wherein the radial inner ring of the planetary gears provides the outer raceway of the planetary gear bearings.

6. The planetary reducer according to claim 1, characterized in that, The planetary reducer also includes a fixed end cover with an anti-rotation boss and an anti-rotation hole at the end of the planetary gear shaft. The anti-rotation boss of the end cover is inserted into the anti-rotation hole to prevent the planetary gear shaft from rotating.

7. The planetary reducer according to claim 1, characterized in that, The planetary reducer also includes a planetary gear bearing, the inner radial ring of which has an anti-rotation boss, and the outer radial ring of which has an anti-rotation groove. The anti-rotation boss is embedded in the anti-rotation groove to prevent the planetary gear bearing from rotating relative to the planetary gear shaft.

8. The planetary reducer according to claim 1, characterized in that, The planetary reducer also includes planetary gear bearings and a second extrusion oil film damper composed of the extrusion oil film damper. For the second extrusion oil film damper, the shaft is the planetary gear shaft, the bore is provided by the planetary gear bearing, and the planetary gear bearing is radially floatingly supported on the planetary gear shaft.

9. A geared turbofan engine, comprising a low-pressure rotor, a fan rotor, and a planetary gear reducer, wherein the low-pressure rotor and the fan rotor are connected via the planetary gear reducer, characterized in that, The planetary gear reducer is the planetary gear reducer as described in any one of claims 1-8.

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