Open fan engine with variable pitch system

Abstract

The application provides an open fan engine with a variable pitch system, which comprises a rotating hydraulic actuating mechanism, an engine low-pressure shaft, a central bevel gear and a plurality of blades, the flywheel shaft of the rotating hydraulic actuating mechanism is connected with the engine low-pressure shaft, and the central bevel gear is installed outside the engine low-pressure shaft; an inclined bevel gear is installed at the handle of each blade, the inclined bevel gear is engaged with the central bevel gear, the blades are arranged around the tooth part of the central bevel gear through the corresponding inclined bevel gears, and the rotation angle adjustment of the blades is realized. The application can realize the adjustment and locking of the blades at any angle, has a small volume, can be modularized in various open fan engines, does not need to make a large change to the existing engine design configuration, the torsion transmission is stable and reliable. Through the design of a cylindrical central inclined bevel gear to drive the rotation of the blades, the disadvantage that a circle of connecting rod transmission mechanisms must be arranged in the traditional adjustment mechanism is avoided, and the overall rigidity is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of open fan engine, in particular to an open fan engine with a variable pitch system. BACKGROUND

[0002] Propfan engine, also known as open rotor engine or unducted fan engine, is a kind of gas turbine engine which drives the propfan structure by the output shaft power of the power turbine. The open fan engine usually has two rows of propfan, the front stage is rotor and the rear stage is stator or rotor.

[0003] The propfan engine of the above type needs a system to adjust the angle of the propfan blades, also known as variable pitch system, to ensure that the power of the engine can always adapt to its working conditions.

[0004] The angle adjustment of the general stator propfan is relatively simple, which can be fixed on the engine case by the actuating mechanism. It drives the connecting rod mechanism through angular contact ball bearing (thrust bearing) and sliding pair, and changes the pitch angle of the stator propfan by four-bar linkage transmission.

[0005] The angle adjustment of the rotor propfan is relatively complex, which needs to force the rotor propfan to rotate around the engine low pressure shaft while rotating around its propfan shaft, so as to realize the adjustment of the pitch angle. The variable pitch system is the core structure of the open fan engine.

[0006] In the prior art, a variable pitch system has been proposed. The adjustment of the conventional open fan engine rotor propfan is basically through the thrust bearing and sliding pair (or straight gear transmission) to drive the connecting rod mechanism, and the pitch angle of the stator propfan is changed by four-bar linkage transmission. This adjusting mechanism needs to design a circle (the number is equal to the number of a circle of propfan) of connecting rod mechanism, which results in a very heavy structure. At the same time, in order to control the angle locking of the blades, the actuating mechanism needs a large thrust and tension. Moreover, the structure is expensive and not convenient to maintain.

[0007] Therefore, the present application inventors design an open fan engine with a variable pitch system to overcome the above technical problems. SUMMARY

[0008] The present application solves the technical problem of overcoming the defects of the prior art, such as heavy structure, high cost and inconvenient maintenance, and provides an open fan engine with a variable pitch system.

[0009] The present application solves the above technical problems by the following technical scheme:

[0010] An open fan engine with a variable pitch system, characterized in that the open fan engine with the variable pitch system comprises a rotary hydraulic actuator, an engine low-pressure shaft, a central bevel gear and a plurality of blades, a flywheel shaft of the rotary hydraulic actuator is connected with the engine low-pressure shaft, and the central bevel gear is installed outside the engine low-pressure shaft.

[0011] An inclined bevel gear is installed at a blade stem of each of the blades, the inclined bevel gear is engaged with the central bevel gear, and the blades are arranged around the tooth portion of the central bevel gear through the corresponding inclined bevel gears, so as to realize the angle adjustment of the blades.

[0012] According to an embodiment of the present application, the central bevel gear is a cylindrical structure, wherein an inner inclined bevel gear is arranged at one end portion, and the inclined bevel gears are arranged in a circle and respectively matched with the inner inclined bevel gear.

[0013] According to an embodiment of the present application, the open fan engine further comprises a flange drum, an outer shell of the rotary hydraulic actuator is fixedly connected with one end portion of the flange drum, and the other end portion of the central bevel gear is fixedly connected with the other end portion of the flange drum.

[0014] According to an embodiment of the present application, a ball bearing is arranged between the flange drum and the engine low-pressure shaft, and used for supporting the flange drum.

[0015] According to an embodiment of the present application, the open fan engine further comprises a mounting disc, one end portion of the mounting disc is connected with the engine low-pressure shaft, and the other end portion is connected with the blade stem of each of the blades.

[0016] According to an embodiment of the present application, an angle sensor is installed at the blade stem of the blade.

[0017] According to an embodiment of the present application, the rotary hydraulic actuator comprises a first outer shell, a flywheel shaft, a flywheel and a second outer shell, the flywheel is installed on the flywheel shaft, and the flywheel shaft and the flywheel are installed in a cavity formed by the clamping connection of the first outer shell and the second outer shell through a bearing.

[0018] According to an embodiment of the present application, the flywheel comprises a plurality of spaced flywheel blades and a cylindrical main body, the flywheel blades are installed on the outer wall surface of the cylindrical main body at intervals;

[0019] At least one first through hole and at least one second through hole are arranged at the cylindrical main body between every two adjacent flywheel blades and staggered with each other, the first through hole is close to the corresponding flywheel blade on one side, and the second through hole is close to the corresponding flywheel blade on the other side.

[0020] According to one embodiment of the present application, the flywheel shaft is provided with an oil inlet and an oil outlet, the first through hole is communicated with the oil inlet, and the second through hole is communicated with the oil outlet.

[0021] Or the second through hole is communicated with the oil inlet, and the first through hole is communicated with the oil outlet.

[0022] According to one embodiment of the present application, the inner wall surface of the first shell is provided with a plurality of mutually spaced blades, the junction of the blades and the inner wall surface is provided with a boss which protrudes outward along the two sides of the blade; each flywheel blade is located between two adjacent blades.

[0023] According to one embodiment of the present application, when the flywheel shaft rotates in the first shell, the boss and the adjacent flywheel blade are in contact with each other, the first through hole or the second through hole is located between the flywheel blade and the blade, and keeps unobstructed.

[0024] According to one embodiment of the present application, the open fan engine further comprises a hydraulic control system connected with the oil inlet and the oil outlet.

[0025] The positive progress effect of the present application is that:

[0026] The open fan engine with a variable pitch system has the following advantages:

[0027] 1. It has a variable pitch system, can realize the adjustment and locking of the blade at any angle, has a small volume, can be modularized in various open fan engines, does not need to make large changes to the existing engine design configuration, and has stable and reliable torque transmission.

[0028] 2. A cylindrical central bevel gear is designed to drive the rotation of the blade, avoiding the disadvantages of a circle of connecting rod transmission mechanism in the traditional adjustment mechanism, and improving the overall stiffness.

[0029] 3. The gear structure of the central bevel gear is designed as internal teeth, effectively improving the cooperation reliability of the central bevel gear and the blade handle pinion.

[0030] 4. A clever rotary hydraulic actuator mechanism is designed, which can realize the adjustment and locking of the blade at any angle, has a small volume, can be modularized in various open fan engines, can perfectly match the existing hydraulic control system and low-pressure shaft design layout of the engine, does not need to make large changes to the existing engine design configuration, and can be easily maintained later.

[0031] 5. The rotary hydraulic actuator mechanism has a limiting function, making the torque transmission more stable and reliable. Attached Figure Description

[0032] The above and other features, properties and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings and embodiments, in which the same reference numerals always denote the same features, wherein:

[0033] Figure 1 This is a schematic diagram of an open-fan engine.

[0034] Figure 2 This is a schematic diagram of the structure of the open fan engine with a variable pitch system according to the present invention.

[0035] Figure 3 This is a schematic diagram of the central bevel gear transmission structure in the open fan engine with variable pitch system of the present invention.

[0036] Figure 4 This is an exploded view of the rotary hydraulic actuator in the open fan engine with variable pitch system of the present invention.

[0037] Figure 5 This is a front view of the rotary hydraulic actuator in the open fan engine with variable pitch system of the present invention.

[0038] Figure 6 This is a side view of the rotary hydraulic actuator in an open-fan engine with a variable pitch system according to the present invention.

[0039] Figure 7 for Figure 6 A sectional view taken along line AA.

[0040] Figure 8 This is a schematic diagram of the assembly of the flywheel shaft, flywheel and first housing in the open fan engine with variable pitch system of the present invention.

[0041] Figure 9 This is a schematic diagram of the assembly of the flywheel shaft and flywheel in the open fan engine with variable pitch system of the present invention.

[0042] Figure 10 for Figure 9 The corresponding main view.

[0043] Figure 11 for Figure 10 A sectional view taken along line BB. Detailed Implementation

[0044] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0045] Embodiments of the present application will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to the preferred embodiments of the present application, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0046] Further, although the terms used in the present application are selected from publicly-known terms, some of the terms mentioned in the specification of the present application can be selected by the applicant from his or her judgment, and the detailed meanings thereof are described in the relevant part of the description herein.

[0047] Further, the present application is to be understood not only in the sense of the

[0048] As shown in Figure 1 the present embodiment is a tractor open fan engine 10, which is a double-row rotor propeller fan design 11, including an aircraft fuselage 12 and an engine inlet 13.

[0049] As shown in Figure 2 the present application discloses an open fan engine with a variable pitch system, which comprises a rotary hydraulic actuator mechanism 100, an engine low-pressure shaft 200, a central bevel gear 300 and a plurality of blades 400. The flywheel shaft 110 of the rotary hydraulic actuator mechanism 100 is connected with the engine low-pressure shaft 200, and the central bevel gear 300 is installed outside the engine low-pressure shaft 200. An inclined bevel gear 410 is installed at the blade handle of each blade 400, the inclined bevel gear 410 is engaged with the central bevel gear 300, and the blade 400 is arranged around the tooth part of the central bevel gear 300 through the corresponding inclined bevel gear 410, so as to realize the angle adjustment of the blade 400.

[0050] As shown in Figure 3 the central bevel gear 300 is preferably a cylindrical structure, one end of which is provided with an inner inclined bevel gear 310, and the inclined bevel gears 410 are arranged in a circle and matched with the inner inclined bevel gear 310 respectively. The central bevel gear 300 is in contact with the inclined bevel gears 410 at the blade handles of the blades 400, so as to realize the angle adjustment of the blades 400.

[0051] In combination Figure 2 , the open fan engine further comprises a flange drum 500, the outer shell of the rotary hydraulic actuator mechanism 100 is fixedly connected with one end of the flange drum 500, and the other end of the central bevel gear 300 is fixedly connected with the other end of the flange drum 500.

[0052] For example, the left and right end housings of the rotary hydraulic actuating mechanism 100 and the flange drum 500 are fixedly connected through a bolt hole 520 (1 string 3). The flange drum 500 is connected with the central bevel gear 300 through a ring of screws. Further, other connection modes can also be used as required.

[0053] Further, in order to strengthen the stability of transmission, a ball bearing 510 can also be arranged between the flange drum 500 and the engine low-pressure shaft 200 for supporting the flange drum 500. The ball bearing 510 is used as a fulcrum, and the ball bearing 510 has fixing devices on the left and right sides.

[0054] Further, the open fan engine also comprises a mounting disc 600, one end of the mounting disc 600 is connected with the engine low-pressure shaft 200, and the other end is connected with the blade handle 420 of each paddle 400.

[0055] The mounting disc 600 of the paddle 400 is connected with the engine low-pressure shaft 200 through a spline, and an angle sensor 430 is installed at the blade handle 420 of the paddle 400. The spline is axially fixed with the shoulder of the engine low-pressure shaft 200 through a nut. The engine cover 800 is fixed with the mounting disc 600 through a casing 810. The whole structure is arranged in the engine inner cavity 900. The paddle bone 440 is fixedly connected with the engine cover 800.

[0056] As shown in Figures 4 to 7 , the rotary hydraulic actuating mechanism 100 comprises a first housing 110, a flywheel shaft 120, a flywheel 130 and a second housing 140. The flywheel 130 is installed on the flywheel shaft 120, and the flywheel shaft 120 and the flywheel 130 are installed in the cavity formed by the clamping connection of the first housing 110 and the second housing 140 through a bearing 150. Sealing rings 160 are arranged between the first housing 110 and the second housing 140, between the flywheel shaft 120 and the first housing 110, and between the flywheel shaft 120 and the second housing 140, so as to realize sealed connection.

[0057] As shown in Figures 9 to 11 , the flywheel 130 comprises a plurality of spaced flywheel blades 131 and a cylindrical body 132, and the flywheel blades 131 are installed on the outer wall surface of the cylindrical body 132 at intervals. At least one first through hole 133 and at least one second through hole 134 are arranged on the cylindrical body 132 between every two adjacent flywheel blades 131, and the first through hole 133 is close to the corresponding flywheel blade 131 on one side, and the second through hole 134 is close to the corresponding flywheel blade 131 on the other side.

[0058] Meanwhile, the flywheel shaft 120 is provided with an oil inlet 121 and an oil outlet 122, so that the first through hole 133 is communicated with the oil inlet 121, and the second through hole 134 is communicated with the oil outlet 122. Alternatively, the second through hole 134 can be communicated with the oil inlet 121, and the first through hole 133 is communicated with the oil outlet 122.

[0059] In combination Figure 8 As shown, the inner wall surface of the first shell 110 is provided with a plurality of mutually spaced vanes 111, and the junction of the vane 111 and the inner wall surface of the first shell 110 is provided with a boss 112 which protrudes outward along the two sides of the vane 111. Each flywheel vane 131 is located between two adjacent vanes 111. Due to the design of the boss 112 on the vane 111 of the first shell 110, the rotary hydraulic actuator 100 has a maximum adjustable range limit, which ensures the safety of the adjusting mechanism.

[0060] When the flywheel shaft 120 rotates in the first shell 110, the boss 112 is in contact with the adjacent flywheel vane 131, the first through hole 133 or the second through hole 134 is located between the corresponding flywheel vane 131 and the vane 111, and remains unobstructed.

[0061] In combination Figure 2 As shown, the open fan engine also includes a hydraulic control system 700, and the hydraulic control system 700 is connected with the oil inlet 121 and the oil outlet 122.

[0062] According to the above structural description, in the open fan engine with a variable pitch system, the rotary hydraulic actuator 100 adopts a modular form, and in order to facilitate the description, the adjusting mechanism of the first stage rotor blade is described in detail. The left end of the flywheel shaft 120 of the rotary hydraulic actuator 100 is connected with the rotary hydraulic joint 160. The left end of the rotary hydraulic joint 160 is a stationary part, and the oil inlet 121 and the oil outlet 122 of the rotary hydraulic joint 160 are connected with the hydraulic control system 700. Further, the hydraulic control system 700 can share the same set with the control system of the engine itself. The flywheel shaft 120 of the rotary hydraulic actuator 100 is connected with the low-pressure shaft 200 of the engine, and the connection mode (not marked in the figure) can be the common shaft and shaft connection mode.

[0063] The variable pitch adjusting principle of the open fan engine with a variable pitch system is as follows:

[0064] The engine low pressure shaft 200 drives the installation disc 600 through the spline, and the installation disc 600 drives the paddle 400 to rotate around the engine low pressure shaft 200. The right end 123 of the flywheel shaft 120 of the rotary hydraulic actuator 100 is fixedly connected with the engine low pressure shaft 200, and the shell of the rotary hydraulic actuator 100 is fixedly connected with the central bevel gear 300 through the flange drum 500.

[0065] When the angle of the paddle 400 does not need to be adjusted, the first shell 110 of the rotary hydraulic actuator 100 is hydraulically matched with the flywheel shaft 120, so as to realize the mutual angle locking between the first shell 110 and the flywheel shaft 120, thereby realizing the mutual rotation angle locking between the central bevel gear 300 and the engine low pressure shaft 200, that is, the mutual locking between the paddle 400 and the engine low pressure shaft 200. In this way, the locking of the angle of the paddle 400 is completed.

[0066] When the paddle 400 needs to be adjusted, the hydraulic control system 700 is started to drive the hydraulic pressure on both sides of the chamber 113, so as to push the flywheel blade 131 on the flywheel shaft 120 and the blade 111 of the first shell 110 to rotate with each other. Through the above transmission relationship, that is, the mutual rotation between the central bevel gear 300 and the engine low pressure shaft 200, the self-rotation of the paddle 400 is realized.

[0067] When the angle sensor 430 at the blade handle recognizes that the angle adjustment is in place, the feedback is given to the hydraulic control system 700, the hydraulic control system 700 locks the hydraulic pressure at this time, so that the whole variable pitch system is locked, and the self-rotation adjustment of the paddle 400 is completed.

[0068] The open fan engine with the variable pitch system has a rotatable hydraulic actuator. When the paddle does not need to be adjusted, the hydraulic actuator and the transmission mechanism can rotate together with the paddle around the engine low pressure shaft, and no relative rotation angle is generated. When the paddle needs to be adjusted, the hydraulic actuator can push the central bevel gear, and then the central bevel gear pushes the small bevel gear at the blade handle, so as to realize the self-rotation angle adjustment of the blade in the rotating state.

[0069] The open fan engine with the variable pitch system has the following characteristics:

[0070] I. The traditional connecting rod mechanism is abandoned, and a cylindrical central bevel gear 300 is used to drive the self-rotation of the blade handle, as shown in Figure 3 .

[0071] Further, the present application suggests that the tooth structure of the central bevel gear is an inner bevel gear, and the small bevel gear at the blade handle is an upside-down bevel gear with a large lower part. This design is due to the fact that the blade will generate a very large centrifugal load when rotating around the low-pressure shaft of the engine, and the small bevel gear at the blade handle will have a tendency to displace radially outward. The use of the inner bevel gear and the inverted bevel gear at the blade handle of the present application can effectively prevent the central bevel gear and the small bevel gear at the blade handle from disengaging, leading to unstable contact. In addition, such a design can effectively enhance the rigidity of the central bevel gear transmission mechanism.

[0072] Secondly, the present application proposes a new type of rotary hydraulic actuator 100, which has been modularized and can be easily installed in various open fan engine variable pitch adjustment systems. A suitable flange drum can be designed according to the needs to connect the rotary hydraulic actuator housing with the central bevel gear described above, and the flywheel shaft of the rotary hydraulic actuator is fixedly connected with the low-pressure shaft 3 of the engine.

[0073] The first housing has a blade structure, which forms many cavities with the flywheel blades on the flywheel shaft. The flywheel shaft has oil holes, so that each cavity has an oil hole. When actuation is needed, hydraulic oil enters the cavities through the oil holes, and through the hydraulic cooperation of the cavities on both sides, the blades are pushed to rotate relative to each other. In this way, the first housing and the flywheel shaft can rotate relative to each other, i.e., the low-pressure shaft of the engine and the central bevel gear can rotate relative to each other. Finally, the central bevel gear pushes the inverted bevel gear at the blade handle, so that the blades can achieve self-rotation adjustment.

[0074] Thirdly, the flywheel shaft of the rotary hydraulic actuator has an oil passage design, which leads hydraulic oil out through one end through a rotary hydraulic joint. One end of the rotary hydraulic joint is a rotor connected with the oil hole of the flywheel shaft. The other end of the rotary hydraulic joint is a stator connected with the hydraulic control system. The hydraulic system has an electromagnetic reversing valve, which can drive the hydraulic pressure in both directions to push the flywheel blades and the blades in the rotary hydraulic actuator to rotate clockwise and counterclockwise, thereby achieving clockwise and counterclockwise rotation angle adjustment of the blades. The hydraulic system also has a pressure relief valve to prevent excessive hydraulic pressure from damaging the actuator.

[0075] Fourthly, the blade handle is equipped with an angle sensor, and the control system adjusts the angle of the blade in real time according to the feedback information of multiple sensors (e.g., 8 sensors) when the rotary hydraulic actuator is adjusting.

[0076] Fifthly, the rotary hydraulic actuator also has a limiting function. Generally, the clockwise and counterclockwise rotation of the blades has a certain adjustable range, and the span of the flywheel blades on the flywheel shaft can be designed according to this range. In this way, the blades of the first housing can only rotate within the span angle of the flywheel blades, thereby playing a limiting protection role to prevent excessive adjustment of the blades.

[0077] Six, the rotating hydraulic actuating mechanism also has the function of locking the angle of the paddle. After the angle of the paddle is adjusted, it is usually necessary to lock the angle so that it can work normally. In the present application, the rotating hydraulic actuating mechanism can lock the angle between the flywheel blade and the blade of the rotating hydraulic actuating mechanism at any angle through the cooperation of the hydraulic pressure on both sides of the chamber (the cavity between the flywheel blade and the blade) and the closing of the hydraulic oil way valve.

[0078] Thus, the angle of the paddle can be locked. In this way, the present application can reduce the disadvantage of additional weight caused by the traditional paddle locking structure.

[0079] For those skilled in the art, the above-mentioned disclosure of the application is only as an example and does not constitute a limitation on the present application. Although it is not explicitly stated here, those skilled in the art can make various modifications, improvements and corrections to the present application. Such modifications, improvements and corrections are suggested in the present application, so such modifications, improvements and corrections still belong to the spirit and scope of the exemplary embodiments of the present application.

[0080] At the same time, specific words are used in the present application to describe the embodiments of the present application. As "one embodiment", "an embodiment" and / or "some embodiments" mean a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "an embodiment" or "one embodiment" or "an alternative embodiment" mentioned in different places in the specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be properly combined.

[0081] Although the above describes the specific embodiments of the present application, those skilled in the art should understand that these are only illustrative, and the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, and such changes and modifications all fall within the protection scope of the present application.

Claims

1. An open fan engine with a variable pitch system, characterized in that, The open fan engine with the variable pitch system comprises a rotary hydraulic actuator, an engine low-pressure shaft, a central bevel gear and a plurality of blades, the flywheel shaft of the rotary hydraulic actuator is connected with the engine low-pressure shaft, and the central bevel gear is installed outside the engine low-pressure shaft; An inclined bevel gear is installed at the stem of each blade, the inclined bevel gear is engaged with the central bevel gear, and the blades are arranged around the tooth portion of the central bevel gear through the corresponding inclined bevel gears, so that the rotation angle of the blades is adjusted. The central bevel gear is in a cylindrical structure, one end of which is provided with an internal inclined bevel gear, and the inclined bevel gears are in a ring and are matched with the internal inclined bevel gear respectively. The open fan engine further comprises a flange drum, the shell of the rotary hydraulic actuator is fixedly connected with one end of the flange drum, and the other end of the central bevel gear is fixedly connected with the other end of the flange drum.

2. The open fan engine with variable pitch system as in claim 1, wherein, A ball bearing is arranged between the flange drum and the engine low-pressure shaft, and is used for supporting the flange drum.

3. The open fan engine with variable pitch system as in claim 1, wherein, The open fan engine further comprises a mounting disc, one end of the mounting disc is connected with the engine low-pressure shaft, and the other end is connected with the stem of each blade.

4. The open fan engine with variable pitch system as in claim 3, wherein, An angle sensor is installed at the stem of the blade.

5. The open fan engine with variable pitch system as in claim 1, wherein, The rotary hydraulic actuator comprises a first shell, a flywheel shaft, a flywheel and a second shell, the flywheel is installed on the flywheel shaft, and the flywheel shaft and the flywheel are installed in the cavity formed by the clamping connection of the first shell and the second shell through a bearing.

6. The open fan engine with variable pitch system as in claim 5, wherein, The flywheel comprises a plurality of spaced flywheel blades and a cylindrical body, and the flywheel blades are installed on the outer wall surface of the cylindrical body at intervals. At least one first through hole and at least one second through hole are arranged at the cylindrical body between every two adjacent flywheel blades and are staggered with each other, the first through hole is close to the corresponding flywheel blade on one side, and the second through hole is close to the corresponding flywheel blade on the other side.

7. The open fan engine with variable pitch system as in claim 6, wherein, An oil inlet and an oil outlet are arranged on the flywheel shaft, the first through hole is communicated with the oil inlet, and the second through hole is communicated with the oil outlet. Or the second through hole is communicated with the oil inlet, and the first through hole is communicated with the oil outlet.

8. The open fan engine with variable pitch system as in claim 6, wherein, A plurality of blades are arranged at the inner wall surface of the first shell at intervals, a boss is arranged at the junction of the blade and the inner wall surface and protrudes outward along the two sides of the blade, and each flywheel blade is located between two adjacent blades.

9. The open fan engine with variable pitch system of claim 8, wherein, When the flywheel shaft rotates in the first shell, the boss is in contact with the adjacent flywheel blade, the first through hole or the second through hole is located between the corresponding flywheel blade and the blade, and keeps unobstructed.

10. The open fan engine with a variable pitch system according to claim 7, characterized in that, The open fan engine further comprises a hydraulic control system, and the hydraulic control system is connected with the oil inlet and the oil outlet.

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