Shaft-seal-free electric fuel pump

Abstract

The invention discloses a shaft-seal-free electric fuel pump, and belongs to the aviation application technology. The shaft-seal-free electric fuel pump comprises a motor and a fuel pump body. The motor and the fuel pump share the motor transmission shaft and the motor rear cover, no shaft seal structure exists, fuel in the fuel pump cavity can enter the motor cavity through the gap between the motor rear cover and the motor transmission shaft, the fuel entering the motor cavity plays a role in cooling the motor, the heat dissipation performance of the motor is improved, and the service life of the motor is prolonged. And the motor transmission shaft is fixedly connected with the impeller through a boss nut and a locking nut. When the motor works, the motor transmission shaft drives the impeller to rotate, fluid in the impeller is thrown to the outer edge of the impeller under the action of centrifugal force and enters the shell, due to the diffusion action of the shell, the flow speed of the fluid is reduced, kinetic energy is converted into static pressure energy, and fuel oil with certain quality is output from an outlet of the shell.

Description

Technical Field

[0001] This invention patent relates to aviation application technology, specifically to a shaft-seal-less electric fuel pump. Background Art

[0002] Electric fuel pumps are widely used in aircraft fuel systems and engine fuel systems, and can be used as fuel boost pumps, starting pumps, and fuel supply and transfer pumps. Electric fuel pumps are important components of aircraft fuel systems and play important roles such as fuel supply, fuel transfer, and heat dissipation.

[0003] To prevent the oil in the fuel pump from flowing into the motor through the gap of the drive shaft, traditional electric fuel pumps usually have a shaft seal structure to ensure the seal at the connection between the fuel pump and the motor. On the one hand, the reliability of traditional shaft seals is low and the service life is short; on the other hand, it is difficult to meet the requirement of dry running for 15 minutes in the fuel pump HB5644 specification, which affects the performance, service life, and reliability of the product.

[0004] This invention adopts an integrated design scheme for the fuel pump and the motor. The motor uses a fully immersed brushless DC motor, and the shaft seal structure of the fuel pump is cancelled, which has the following advantages:

[0005] 1. It can solve the reliability problem of the fuel pump shaft seal and improve the service life and reliability of the fuel pump;

[0006] 2. It can meet the requirement of dry running for 15 minutes in the fuel pump HB5644 specification;

[0007] 3. The motor is in the oil, and the heat dissipation performance is better, which improves the reliability of the motor;

[0008] 4. It can reduce the axial dimension of the electric fuel pump, shorten the length of the motor extension shaft, reduce the deflection of the shaft, and improve the machining processability of the motor drive shaft.

[0009] Generally speaking, this technology can improve the reliability of the fuel pump and ensure the performance of the product such as light weight, high power-to-mass ratio, long service life, and long dry running time.

[0010] Contents of the Invention Patent

[0011] Aiming at the above problems, the purpose of this invention patent is to provide a shaft-seal-less electric fuel pump to improve the performance and reliability of electric fuel pump products.

[0012] This application relates to a shaftless-seal electric fuel pump. The shaftless-seal electric fuel pump includes a motor 1 and a fuel pump. The motor 1 includes a motor drive shaft 2 and a motor rear cover 3; the fuel pump includes an impeller 4, a housing 10, a front cover 9, an adjusting gasket 13, a boss nut 7, a lock nut 8, a screw A 6, a screw B 12, a rubber ring A 5, a rubber ring B 11, and the motor rear cover 3; the motor 1 and the fuel pump share the motor drive shaft 2 and the motor rear cover 3, and there is no shaft-seal structure. The fuel in the fuel pump chamber can enter the motor 1 chamber through the gap between the motor rear cover 3 and the motor drive shaft 2. The fuel entering the motor 1 chamber cools the motor 1, improves the heat dissipation performance of the motor 1, and extends the service life of the motor 1.

[0013] The motor drive shaft 2 and the impeller 4 are fixedly connected through the boss nut 7 and the lock nut 8. When the motor 1 operates, the motor drive shaft 2 drives the impeller 4 to rotate. The fluid in the impeller 4 is thrown towards the outer edge of the impeller 4 under the action of centrifugal force. The fluid enters the housing 10. Due to the diffusion effect of the housing 10, the fluid velocity decreases, and the kinetic energy is converted into static pressure energy, and a certain quality of fuel is output from the outlet of the housing 10.

[0014] Furthermore, the motor rear cover 3 and the middle housing 10 are connected by a screw B 12. The front cover 9 and the middle housing 10 are connected by a screw B 12.

[0015] Furthermore, the gap between the impeller 4 and the front cover 9 and the motor rear cover 3 is adjusted by the adjusting gasket 13; the front cover 9 and the housing 10 are sealed by the rubber ring A 5, and the motor rear cover 3 and the housing 10 are sealed by the rubber ring B 11.

[0016] Furthermore, the motor drive shaft 2 is connected to the impeller 4, and the connection between the motor drive shaft 2 and the impeller 4 is a clearance fit of hole and shaft; four impeller grooves are machined at the end face of the impeller 4 near the front cover 9 for connection with the boss nut 7. The impeller grooves are evenly distributed in the circumferential direction of the end face of the impeller 4 and are opened along the axial direction of the end of the impeller 4; a certain length of thread is machined at the end face of the motor drive shaft 2 near the front cover 9; after the impeller 4 is installed on the motor drive shaft 2, the boss nut 7 is screwed onto the motor drive shaft 2 and fitted with the impeller grooves on the impeller 4. The impeller 4 and the motor drive shaft 2 are fixedly connected by tightening the boss nut 7, and then the lock nut 8 is screwed onto the motor drive shaft 2 and tightened.

[0017] Furthermore, four convex blocks are provided on the end face of the boss nut 7. The convex blocks are evenly distributed in the circumferential direction of the end face of the boss nut 7 and are set along the axial direction of the end of the boss nut 7. The size of the convex blocks is the same as that of the impeller grooves on the impeller 4. The convex blocks are snapped into the impeller grooves on the impeller 4 to achieve fixation.

[0018] Advantages of this invention patent:

[0019] 1. This invention patent uses a fully immersed oil brushless DC motor, which is beneficial to improving the heat dissipation performance of the motor and extending the service life of the motor.

[0020] 2. This invention patent cancels the shaft seal structure between the motor and the fuel pump, which can not only achieve reliable sealing of the product, but also ensure the product has the properties of light weight, high power-to-mass ratio, long service life, long dry running time, etc., and improve the reliability of the product. Brief Description of the Drawings

[0021] Figure 1 It is a two-dimensional cross-sectional view of a shaft-seal-less electric fuel pump of this invention patent.

[0022] Figure 2 It is a schematic assembly diagram of the boss nut, motor, motor drive shaft and impeller of the present invention.

[0023] In the figure: 1 motor, 2 motor drive shaft, 3 motor rear cover, 4 impeller, 5 rubber ring A, 6 screw A, 7 boss nut, 8 lock nut, 9 front cover, 10 housing, 11 rubber ring B, 12 screw B, 13 adjusting gasket. Detailed Embodiment

[0024] The following further describes this invention patent in conjunction with the drawings and embodiments.

[0025] As Figure 1 shown, a shaft-seal-less electric fuel pump, the shaft-seal-less electric fuel pump includes a motor 1 and a fuel pump. The motor 1 includes a motor drive shaft 2 and a motor rear cover 3; the fuel pump includes an impeller 4, a housing 10, a front cover 9, an adjusting gasket 13, a boss nut 7, a lock nut 8, a screw A 6, a screw B 12, a rubber ring A 5, a rubber ring B 11 and a motor rear cover 3; the motor 1 and the fuel pump share the motor drive shaft 2 and the motor rear cover 3, without a shaft seal structure, and the fuel in the fuel pump cavity can enter the motor 1 cavity through the gap between the motor rear cover 3 and the motor drive shaft 2. The fuel entering the motor 1 cavity cools the motor 1, improves the heat dissipation performance of the motor 1, and extends the service life of the motor 1. The motor drive shaft 2 and the impeller 4 are fixedly connected by a boss nut 7 and a lock nut 8. When the motor 1 works, the motor drive shaft 2 drives the impeller 4 to rotate. The fluid in the impeller 4 is thrown to the outer edge of the impeller 4 under the action of centrifugal force. The fluid enters the housing 10. Due to the diffusion effect of the housing 10, the fluid velocity decreases, and the kinetic energy is converted into static pressure energy, and a certain quality of fuel is output from the outlet of the housing 10.

[0026] The rear cover 3 of the motor is connected to the middle housing 10 by screws B12. The front cover 9 is connected to the middle housing 10 by screws B12. The impeller 4 adjusts the clearance between the impeller 4 and the front cover 9 and the rear cover 3 of the motor through the adjusting gasket 13; the front cover 9 and the housing 10 are sealed by the rubber ring A5, and the rear cover 3 of the motor and the housing 10 are sealed by the rubber ring B11. The motor drive shaft 2 is connected to the impeller 4, and the connection between the motor drive shaft 2 and the impeller 4 is a clearance fit of hole and shaft; four impeller grooves are machined at the end face of the impeller 4 near the front cover 9 for connecting with the boss nut 7, and the impeller grooves are evenly distributed in the circumferential direction of the end face of the impeller 4 and are arranged along the axial direction of the end of the impeller 4; a thread of a certain length is machined at the end face of the motor drive shaft 2 near the front cover 9; after the impeller 4 is installed on the motor drive shaft 2, the boss nut 7 is screwed onto the motor drive shaft 2 and fitted with the impeller grooves on the impeller 4, and the impeller 4 and the motor drive shaft 2 are fixedly connected by tightening the boss nut 7, and then the locking nut 8 is screwed onto the motor drive shaft 2 and tightened. Four convex blocks are arranged on the end face of the boss nut 7, and the convex blocks are evenly distributed in the circumferential direction of the end face of the boss nut 7 and are set along the axial direction of the end of the boss nut 7, and the size of the convex blocks is the same as that of the impeller grooves on the impeller 4. The convex blocks are snapped into the impeller grooves on the impeller 4 to achieve fixation.

[0027] As mentioned above, it is only the specific implementation mode of the present invention patent, but the protection scope of the present invention patent is not limited thereto. Any change or replacement that is thought of without creative work should be covered within the protection scope of the present invention patent. Therefore, the protection scope of the present invention patent should be subject to the protection scope defined by the claims.

Claims

1. A shaftless sealed electric fuel pump, characterized in that, The shaftless-seal electric fuel pump includes a motor (1) and a fuel pump; the motor (1) includes a motor drive shaft (2) and a motor rear cover (3); the fuel pump includes an impeller (4), a housing (10), a front cover (9), an adjusting gasket (13), a boss nut (7), a locking nut (8), an O-ring A (5), an O-ring B (11), and a motor rear cover (3); the motor (1) and the fuel pump share the motor drive shaft (2) and the motor rear cover (3), with a shaftless-seal structure. The fuel in the fuel pump chamber can enter the motor (1) chamber through the gap between the motor rear cover (3) and the motor drive shaft (2). The fuel entering the motor (1) chamber cools the motor (1), improves the heat dissipation performance of the motor (1), and extends the service life of the motor (1). The motor drive shaft (2) and the impeller (4) are fixedly connected by the boss nut (7) and the locking nut (8); when the motor (1) operates, the motor drive shaft (2) drives the impeller (4) to rotate. The fluid in the impeller (4) is thrown towards the outer edge of the impeller (4) by the centrifugal force. The fluid enters the housing (10). Due to the diffusion effect of the housing (10), the fluid velocity decreases, and the kinetic energy is converted into static pressure energy, and fuel of a certain quality is output from the outlet of the housing (10). The gap between the impeller (4) and the front cover (9) and the motor rear cover (3) is adjusted by the adjusting gasket (13); the front cover (9) and the housing (10) are sealed by the O-ring A (5), and the motor rear cover (3) and the housing (10) are sealed by the O-ring B (11). The motor drive shaft (2) is connected to the impeller (4), and the connection between the motor drive shaft (2) and the impeller (4) is a clearance fit of hole and shaft; four impeller grooves are machined at the end face of the impeller (4) near the front cover (9) for connection with the boss nut (7). The impeller grooves are evenly distributed in the circumferential direction of the end face of the impeller (4) and are arranged along the axial direction of the end of the impeller (4); a thread of a certain length is machined at the end face of the motor drive shaft (2) near the front cover (9); after the impeller (4) is installed on the motor drive shaft (2), the boss nut (7) is screwed onto the motor drive shaft (2) and fitted with the impeller grooves on the impeller (4). The impeller (4) and the motor drive shaft (2) are fixedly connected by tightening the boss nut (7), and then the locking nut (8) is screwed onto the motor drive shaft (2) and tightened. Four convex blocks are arranged on the end face of the boss nut (7). The convex blocks are evenly distributed in the circumferential direction of the end face of the boss nut (7) and are arranged along the axial direction of the end of the boss nut (7). The size of the convex blocks is the same as that of the impeller grooves on the impeller (4); the convex blocks are clamped into the impeller grooves on the impeller (4) to achieve fixation.

2. The shaftless sealed electric fuel pump according to claim 1, characterized in that The motor rear cover (3) and the middle housing (10) are connected by a screw B (12); the front cover (9) and the middle housing (10) are connected by a screw B (12).

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