Externally lubricated brushless generator for micro turbojet engine

Abstract

The invention relates to the technical field of micro turbojet engines, and is an externally lubricated brushless starter and generator for micro turbojet engines, comprising a motor housing, a front bearing, and a rear bearing. The outer ring of the front bearing is supported in a front bearing installation cavity provided on the inner side of a motor front cover, and is compressed and sealed by a front cover pressure plate. A first oil path hole is provided in the motor front cover, and the front bearing installation cavity is connected to a bearing lubrication pipeline through the first oil path hole; the outer ring of the rear bearing is supported in a rear bearing installation cavity provided on the inner side of a motor rear cover, and a second oil path hole is provided in the motor rear cover, and the rear bearing installation cavity is connected to a bearing lubrication pipeline through the second oil path hole; at least one heat dissipation through-hole is provided on both the motor front cover and the motor rear cover; the invention uses lubricating oil at two places to lubricate the front and rear bearings, and high-speed airflow and oil mist take away a large amount of heat generated during high-speed operation, thereby simultaneously improving the lubrication and heat dissipation effects, and the motor has a long service life and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of micro turbojet engines, and in particular to a starter-generator of a micro turbojet engine. Background Art

[0002] Micro turbojet engines are used in small drones, target drones or missiles. When starting, the starter motor installed at the front end of the engine drives the rotor component to rotate to a certain speed, and then the engine is ignited and started by injecting fuel. After the start is successful, the engine rotor component is separated from the starter motor. The starter motor does not have the function of generating electricity. According to the needs of the aircraft, the starter motor can be replaced with a starter generator. After the start is successful, the rotor component of the micro turbojet engine drives the starter generator to generate electricity, providing a certain power of electricity to the aircraft, reducing the battery load and improving the engine efficiency. Brushless motors have the characteristics of no brush sparks, high efficiency, low noise, and long life. Most advanced micro turbojet engines use brushless motors as starters.

[0003] In the prior art, brushless starters of the same level used in micro turbojet engines use grease-lubricated bearings, which are difficult to withstand high-speed working conditions. Grease is pre-injected into the bearings when they are installed in the brushless starter, and there is no external lubricating oil source during the working process. The lubrication effect is poor during high-speed operation, and severe heat generation will cause problems such as demagnetization and coil aging, which will lead to high-temperature failure of the brushless starter. Summary of the invention

[0004] The purpose of the present invention is to avoid the defects of the prior art and provide an externally lubricated brushless generator for a micro turbojet engine that works at high power and completely solves the problem of high-temperature failure of the generator.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: an externally lubricated brushless generator for a micro turbojet engine, comprising a motor housing, a motor front cover, a motor rear cover, a motor wire, and a motor stator coil fixed inside the motor housing, and both ends of the motor rotor are placed in the bearing inner rings of the front bearing and the rear bearing to support the motor rotor to rotate in the middle cavity of the motor stator coil, the outer ring of the front bearing is supported in the front bearing installation cavity provided on the inner side of the motor front cover, and is compressed and sealed by the front cover pressure plate, a first oil passage hole is provided in the motor front cover, and the front bearing installation cavity is connected to the bearing lubrication pipeline through the first oil passage hole; the outer ring of the rear bearing is supported in the rear bearing installation cavity provided on the inner side of the motor rear cover, and a second oil passage hole is provided in the motor rear cover, and the rear bearing installation cavity is connected to the bearing lubrication pipeline through the second oil passage hole; at least one heat dissipation through-hole is provided on both the motor front cover and the motor rear cover;

[0006] The lubricating oil leading to the rear bearing forms oil mist under the action of the high-speed airflow flowing into the high-speed rotating rear bearing and the heat dissipation through hole on the rear cover of the motor. After the oil mist flows through the cavity between the motor rotor and the motor stator coil, it flows out from the heat dissipation through hole on the front cover of the motor.

[0007] The lubricating oil leading to the front bearing forms oil mist under the action of the high-speed rotating front bearing and the high-speed airflow, and flows out from the heat dissipation through holes on the front cover of the motor.

[0008] Furthermore, a first flow limiting tube and a second flow limiting tube are respectively installed in the first oil circuit hole and the second oil circuit hole. After the lubricating oil is limited by the first flow limiting tube and the second flow limiting tube, it flows through the first oil circuit hole and the second oil circuit hole into the front bearing mounting cavity and the rear bearing mounting cavity.

[0009] Furthermore, the front cover pressure plate fixes the front bearing to the inner side of the motor front cover through the front cover pressure plate fixing screws; the front cover pressure plate together with the motor front cover and the front bearing are installed at the front end of the motor housing through the front cover fixing screws; the motor rear cover together with the rear bearing are installed at the rear end of the motor housing through the rear cover fixing screws.

[0010] Furthermore, the motor front cover and the motor rear cover are disc-shaped; and 3 to 10 heat dissipation holes are evenly distributed in the circumference of the motor front cover and the motor rear cover.

[0011] Furthermore, at least one motor wire is led out from the stator coil of the motor and passes through the hole on the rear cover of the motor.

[0012] Furthermore, the generator is a three-phase brushless motor, and three motor wires are led outward from the stator coil of the motor.

[0013] Furthermore, the oil supply pressure of the bearing lubrication pipeline is 0-1Mpa.

[0014] Furthermore, the front bearing and the rear bearing are both P4 grade front angular contact ceramic bearings.

[0015] Furthermore, at least one layer of Kevlar fiber is wrapped around the outer surface of the motor rotor.

[0016] Furthermore, the motor rotor is made of neodymium boron magnet that is resistant to high temperatures of 180°; and the motor rotor and motor stator coils are both treated to prevent oil mist.

[0017] The beneficial effects of the present invention are:

[0018] 1. The externally lubricated brushless generator for a micro turbojet engine, when working, supplies lubricating oil to the front bearing and the rear bearing through the bearing lubrication pipeline from the external lubricating oil source, and the lubricating oil flows through the rear bearing, the motor rotor, the motor stator coil, and the front bearing, and then flows out from the motor heat dissipation hole. While the lubricating oil in the two places lubricates the front and rear bearings, the high-speed airflow and oil mist take away a large amount of heat generated during high-speed operation through the heat dissipation holes, greatly improving the lubrication and heat dissipation effects.

[0019] 2. The motor rotor is made of high-temperature resistant 180° neodymium boron magnet, and is wrapped with Kevlar fiber. The front and rear bearings are made of P4-grade angular contact high-speed ceramic bearings, which enables long-term use under high-temperature and high-speed conditions, greatly improving the service life of the motor, thereby effectively increasing the speed that the brushless generator can withstand.

[0020] 3. The setting of the flow limiting tube reduces the lubricating oil consumption and the use cost while meeting the lubrication demand.

[0021] 4. The motor rotor and the motor stator coil are both treated to prevent oil mist. After passing through the bearing, the lubricating oil flows through the motor coil and the rotor to form an oil film, which can cool the motor coil and the rotor and extend the service life of the motor.

[0022] The above beneficial effects completely solve the problem of poor lubrication and heat dissipation at high speed in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the present invention;

[0024] Figure 2 It is a left-side structural schematic diagram of the present invention;

[0025] Figure 3 It is a right-side structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0027] Example 1: Figure 1 , Figure 2 , Figure 3As shown, an externally lubricated brushless generator for a micro turbojet engine comprises a motor housing 3, a motor front cover 8, a motor rear cover 1, a motor wire 12, and a motor stator coil 4 fixed inside the motor housing 3. Both ends of a motor rotor 5 are placed on the inner rings of a front bearing 10 and a rear bearing 9 to support the motor rotor 5 to rotate in the middle cavity of the motor stator coil 4. The outer ring of the front bearing 10 is supported in a front bearing mounting cavity provided on the inner side of the motor front cover 8 and is compressed and sealed by a front cover pressure plate 6. The front cover pressure plate 6 fixes the front bearing 10 to the inner side of the motor front cover 8 through a front cover pressure plate fixing screw 11; the front cover pressure plate 6, together with the motor front cover 8 and the front bearing 10, is fixed to the inner side of the motor front cover 8 by ... The front cover fixing screw 7 is installed at the front end of the motor housing 3, and a first oil passage hole 14 is provided in the motor front cover 8, and the front bearing installation cavity is connected to the bearing lubrication pipeline 13 through the first oil passage hole 14; the outer ring of the rear bearing 9 is supported in the rear bearing installation cavity provided on the inner side of the motor rear cover 1, and the motor rear cover 1 together with the rear bearing 9 is installed at the rear end of the motor housing 3 through the rear cover fixing screw 2, and a second oil passage hole 15 is provided in the motor rear cover 1, and the rear bearing installation cavity is connected to the bearing lubrication pipeline 13 through the second oil passage hole 15; four first heat dissipation through holes 17 are provided on the motor front cover 8, and four second heat dissipation through holes 16 are provided on the motor rear cover 1;

[0028] At least one motor wire 12 is led out from the motor stator coil 4 and passes through the hole on the motor rear cover 1. The generator is a three-phase brushless motor, and three motor wires are led out from the motor stator coil.

[0029] The externally lubricated brushless starter and generator for a micro turbojet engine described in the present invention, when working, an external lubricating oil source supplies lubricating oil to a front bearing 10 and a rear bearing 9 through a bearing lubricating pipeline 13, and then, the lubricating oil leading to the rear bearing 9 forms oil mist under the action of the high-speed airflow flowing into the high-speed rotating rear bearing 9 and the heat dissipation through hole 16 on the motor rear cover 1, and the oil mist flows through the cavity between the motor rotor 5 and the motor stator coil 4, and then flows out through the heat dissipation through hole on the motor front cover 8, that is, the bearing is cooled, the working environment of the bearing is improved, and the service life of the bearing is increased; the lubricating oil leading to the front bearing 10 forms oil mist under the action of the high-speed rotating front bearing 10 and the high-speed airflow, and flows out through the heat dissipation through hole on the motor front cover 8; while the two lubricating oils lubricate the front and rear bearings, the high-speed airflow and the oil mist take away a large amount of heat generated by the high-speed operation and high-power power generation of the motor through the heat dissipation holes, greatly improving the lubrication and heat dissipation effects.

[0030] Since heat dissipation is very important when the generator generates high power, holes are opened on the front and rear covers of the motor as much as possible to use the high-speed airflow of the engine intake to dissipate heat from the bearings, stator coils, and rotors inside the motor. At the same time, a motor radiator will be installed outside the motor during installation to quickly dissipate the heat inside the motor, also using the high-speed airflow of the engine intake to take away the heat. Lowering the engine operating temperature within a reasonable range can ensure the power generation and reliability of the motor.

[0031] The motor rotor 5 and the motor stator coil 4 are both treated with anti-oil mist, which is a prior art. After the lubricating oil passes through the bearing, it flows through the motor coil and the rotor to form an oil film, which can quickly cool the motor coil and the rotor and extend the service life of the motor.

[0032] When the micro-turbojet engine is started, the brushless starter generator drives the micro-turbojet engine rotor component to rotate synchronously through the coupling. When the micro-turbojet engine is successfully ignited and started, the rotor component speed increases, driving the brushless starter generator to generate electricity. The brushless starter generator of the micro-turbojet engine in the prior art is damaged after generating electricity for a few minutes at a high speed of 100,000 r / min, and cannot withstand the same speed as the micro-turbojet engine, and cannot generate high-power electricity. The motor rotor 5 of the present invention adopts high temperature resistant 180° neodymium boron magnet, and Kevlar fiber is used to wrap the motor rotor 5 with at least one layer, and the bearings at both ends of the electronic rotor 5 adopt P4 angular contact high-speed ceramic bearings, which can be used for a long time under high temperature and high speed conditions, greatly improving the service life of the motor, thereby effectively improving the speed that the brushless generator can withstand, and can withstand a temperature of 180°C and a speed of 100,000 revolutions per minute for high-power power generation; combined, during the operation of the engine, a large amount of high-speed airflow will flow through the brushless generator, and the high-speed airflow can effectively take away the heat generated by the brushless generator through the heat dissipation holes of the front and rear covers of the brushless generator. Further, the lubricating oil lubricates the front and rear bearings while also taking away the heat generated during high-speed operation, solving the problems of poor lubrication effect and high-temperature failure at high speed in the prior art. It is measured that the brushless generator described in Example 1 of the present invention can withstand a high speed of 100,000 r / min and generate 1000W of high power at high speed.

[0033] Embodiment 2: Same as Embodiment 1, except that: a first flow restricting tube and a second flow restricting tube are respectively installed in the first oil path hole and the second oil path hole, and the lubricating oil flows through the first oil path hole and the second oil path hole into the front bearing mounting cavity and the rear bearing mounting cavity after the lubricating oil amount is limited by the first flow restricting tube and the second flow restricting tube. The lubricating oil amount is limited by setting the flow restricting tube before entering the bearing cavity, and after the flow is limited, the lubricating oil amount meets the lubrication demand while reducing the lubricating oil consumption and reducing the use cost.

[0034] It is measured that the brushless starter-generator described in Example 2 of the present invention does not affect the fuel consumption of the engine, the maximum power generation power of the motor is 1200W, and the pressure flow rate of the current limiting tube is 70ml / 0.8Mpa / min per minute.

[0035] Embodiment 3: Same as Embodiment 1, except that the motor front cover 8 and the motor rear cover 1 are disc-shaped; 3-10 first heat dissipation holes 17 and second heat dissipation holes 16 are evenly distributed in the circumference of the motor front cover 8 and the motor rear cover 1.

[0036] To limit the present invention, any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An externally lubricated brushless generator for a micro turbojet engine, comprising a motor housing, a motor front cover, a motor rear cover, a motor wire, and a motor stator coil fixed inside the motor housing, and the two ends of the motor rotor are placed on the bearing inner rings of the front bearing and the rear bearing to support the motor rotor to rotate in the middle cavity of the motor stator coil, characterized in that: The outer ring of the front bearing is supported in the front bearing installation cavity provided on the inner side of the front cover of the motor, and is pressed and sealed by the front cover pressure plate. A first oil passage hole is provided in the front cover of the motor, and the front bearing installation cavity is connected to the bearing lubrication pipeline through the first oil passage hole; the outer ring of the rear bearing is supported in the rear bearing installation cavity provided on the inner side of the rear cover of the motor, and a second oil passage hole is provided in the rear cover of the motor, and the rear bearing installation cavity is connected to the bearing lubrication pipeline through the second oil passage hole; at least one heat dissipation through hole is provided on both the front cover and the rear cover of the motor; The lubricating oil leading to the rear bearing forms oil mist under the action of the high-speed airflow flowing into the high-speed rotating rear bearing and the heat dissipation through hole on the rear cover of the motor. After the oil mist flows through the cavity between the motor rotor and the motor stator coil, it flows out from the heat dissipation through hole on the front cover of the motor. The lubricating oil leading to the front bearing forms oil mist under the action of the high-speed rotating front bearing and the high-speed airflow, and flows out from the heat dissipation through holes on the front cover of the motor.

2. The externally lubricated brushless generator for a micro turbojet engine according to claim 1, characterized in that: A first flow limiting tube and a second flow limiting tube are installed in the first oil circuit hole and the second oil circuit hole respectively. The lubricating oil flows through the first oil circuit hole and the second oil circuit hole into the front bearing mounting cavity and the rear bearing mounting cavity after the amount of lubricating oil is limited by the first flow limiting tube and the second flow limiting tube.

3. The externally lubricated brushless generator for a micro turbojet engine according to claim 1, characterized in that: The front cover pressure plate fixes the front bearing to the inner side of the motor front cover through the front cover pressure plate fixing screws; the front cover pressure plate together with the motor front cover and the front bearing are installed at the front end of the motor housing through the front cover fixing screws; the motor rear cover together with the rear bearing are installed at the rear end of the motor housing through the rear cover fixing screws.

4. The externally lubricated brushless generator for a micro turbojet engine according to claim 1, characterized in that: The motor front cover and the motor rear cover are disc-shaped; and 3 to 10 heat dissipation holes are evenly distributed in the circumference of the motor front cover and the motor rear cover.

5. The externally lubricated brushless generator for a micro turbojet engine according to claim 1, characterized in that: Lead out at least one motor wire from the motor stator coil and pass it through the hole on the rear cover of the motor.

6. The externally lubricated brushless generator for a micro turbojet engine according to claim 5, characterized in that: The generator is a three-phase brushless motor, and three motor wires are led outward from the stator coil of the motor.

7. The externally lubricated brushless generator for a micro turbojet engine according to claim 1, characterized in that: The oil supply pressure of the bearing lubrication pipeline is 0-1Mpa.

8. The externally lubricated brushless generator for a micro turbojet engine according to any one of claims 1 to 7, characterized in that: The front bearing and the rear bearing are both P4-grade front angular contact ceramic bearings.

9. The externally lubricated brushless generator for a micro turbojet engine according to any one of claims 1 to 7, characterized in that: At least one layer of Kevlar fiber is wrapped around the outer surface of the motor rotor; 10. The externally lubricated brushless generator for a micro turbojet engine according to any one of claims 1 to 7, characterized in that: The motor rotor is made of neodymium boron magnetic steel that is resistant to high temperatures of 180°, and both the motor rotor and the motor stator coil are treated to prevent oil mist.

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