Radial hole type self-cooling fan for outer rotor starter generator

Abstract

The utility model provides a radial hole type self-cooling fan for an outer rotor starter generator, and belongs to the field of machinery. The problems that an existing outer rotor generator stator is poor in heat dissipation and has no space position for installing a heat dissipation structure are solved. The motor comprises a winding which is arranged in an outer rotor casing; and the plurality of air inlet parts are distributed on the peripheral wall of the outer rotor shell and are used for forming radial airflow acting on the winding when the outer rotor shell rotates. The cooling device is mainly used for cooling the stator of the outer rotor generator.

Description

Technical Field

[0001] This utility model belongs to the field of machinery, and in particular relates to a borehole type self-cooling fan for an external rotor generator. Background Technology

[0002] In small and medium-sized aircraft, starter-generator systems are increasingly widely used. The function of a starter-generator system is to work in conjunction with the aircraft engine, generating torque during startup to start the engine and run it to cold-start speed. After startup, the engine runs at high speed through gasoline or diesel combustion, and its shaft drives the generator rotor to rotate and generate electricity. The generator windings output three-phase AC power, which is rectified into DC power by the starter-generator controller to charge the battery or be output externally. Of these two states, the generator mode is where the motor operates the longest. Furthermore, due to the application environment, starter-generators must be small in size and light in weight, and operate with high power density. Therefore, long-term safe and reliable operation in generator mode is one of the important indicators of a starter-generator system and also the most important indicator for users.

[0003] The most critical factor determining the long-term safe operation of a generator is cooling conditions. Insufficient cooling will cause the stator windings to overheat and exceed their insulation limits, ultimately burning out. For ease of assembly, most existing generators are designed with a separate external rotor structure, such as... Figure 4 As shown in the diagram. In such a structure, the heat-generating stator components are located inside the motor, which is inherently not conducive to heat dissipation. Furthermore, due to limited space, it is impossible to install an additional fan to provide cooling for the stator components. Therefore, improving the cooling conditions within the motor itself becomes the best solution. Utility Model Content

[0004] In view of this, the present invention aims to propose a bore-type self-cooling fan for an external rotor generator, so as to solve the problem of poor stator heat dissipation and lack of space for installing heat dissipation structure in existing external rotor generators.

[0005] To achieve the above objectives, this utility model adopts the following technical solution: a borehole-type self-cooling fan for an external rotor generator, comprising:

[0006] The windings are located inside the outer rotor housing;

[0007] The air inlet is provided with several units distributed on the peripheral wall of the outer rotor housing, which are used to generate radial airflow acting on the winding when the outer rotor housing rotates.

[0008] Furthermore, the outer rotor housing has a certain thickness.

[0009] Furthermore, the thickness is 4-6 mm.

[0010] Furthermore, the axial position of the air inlet corresponds to the winding end of the winding.

[0011] Furthermore, several of the aforementioned air inlets are arranged in a circumferentially distributed manner on the peripheral wall of the outer rotor housing.

[0012] Furthermore, the outer rotor housing sidewall is provided with the same number of weight-reducing sections as the air inlet sections, and all the weight-reducing sections are arranged alternately with all the air inlet sections.

[0013] Furthermore, the air inlet is a ventilation hole arranged radially along the outer rotor housing, and the axis of the ventilation hole and the projection of the radial direction of the outer rotor housing onto the same virtual plane have a certain angle.

[0014] Furthermore, the air inlet of the ventilation hole faces the direction of rotation at an angle of attack.

[0015] Furthermore, the angle of attack range is 40-60 degrees.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. This fan generates airflow along the radial direction of the outer rotor housing through the high-speed rotation of the outer rotor, which can cool the windings and reduce the working temperature of the stator components, reliably extending the working time of the motor. By generating airflow on the heat-generating components through the rotation of the outer rotor housing itself, it does not require additional space or additional power, solving the heat dissipation problem under high load, high heat generation and space and weight constraints in the aviation environment, which is of great significance to the stability of motors in aviation conditions.

[0018] 2. This fan applies radial airflow to the winding ends, thereby reducing the temperature at the winding ends. Through conduction, this reduces the temperature of the entire winding, thus controlling the stator temperature. Attached Figure Description

[0019] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0020] Figure 1 This is a cross-sectional view of a bore-type self-cooling fan for an external rotor generator according to the present invention.

[0021] Figure 2 This is a schematic diagram showing the rotation direction of the air inlet and the outer rotor housing of the present invention.

[0022] Figure 3 This is a radial view of the air inlet section described in this utility model;

[0023] Figure 4 This is a schematic diagram of an existing external rotor starter motor.

[0024] 1. Outer rotor housing; 2. Air inlet; 3. Winding end; 4. Weight reduction section. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present utility model can be combined with each other, and the described embodiments are only some embodiments of the present utility model, not all embodiments.

[0026] It should be noted that the descriptions of "left," "right," "left side," "right side," "upper part," "lower part," "top," and "bottom" in this utility model are defined based on the orientation or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and are not intended to indicate or imply that the described structure must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0027] In the description of this utility model, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] Referring to the accompanying drawings, this embodiment describes a borehole-type self-cooling fan for an external rotor generator, comprising:

[0029] The winding is located inside the outer rotor housing 1;

[0030] Air inlets 2, consisting of several units distributed along the perimeter of the outer rotor housing 1, generate radial airflow acting on the windings as the outer rotor housing 1 rotates. Specifically, air inlets 2 are ventilation holes, which must have a certain angle of inclination, commonly 45 degrees, and the angle of attack of the air inlet must face the direction of rotation. In this configuration, as the outer rotor housing 1 rotates, the angle of attack draws air radially into the interior, acting on the windings and thus cooling them. For the same mechanical dimensions, the cross-sectional area of ​​the ventilation holes should be as large as possible to achieve optimal cooling; rounded rectangular holes are ideal, reducing airflow resistance and increasing intake volume. The more air inlets 2, the better; typically, 6-12 ventilation holes can be designed. In the aerospace field, the weight of any component has a significant impact on the overall weight. The shaft of the outer rotor motor requires the installation of many components, and some manufacturing processes necessitate the encapsulation of the windings, posing a significant challenge to internal space. These extra components increase the overall weight, thus presenting a major challenge to the cooling system. Currently, this cooling problem remains unresolved. However, this structure, through the rotation of the outer rotor housing 1 and the placement of the air inlet 2, achieves both structural strength and reduced weight of the outer rotor housing 1. Simultaneously, without adding any components, it generates radial airflow to the winding ends 3, without affecting the existing arrangement of any motor components, yet delivering excellent heat dissipation. This significantly enhances the continuous operation capability of the aircraft motor, and correspondingly improves reliability and durability, making it of great significance and solving the long-standing heat dissipation problem in this field.

[0031] In this embodiment, the outer rotor housing 1 has a certain thickness of 4-6mm. With this thickness, it provides a basis for forming the angle of attack of the air intake, and when the outer rotor housing 1 rotates, it can form an airflow that flows radially.

[0032] In this embodiment, the air inlet 2 is positioned corresponding to the winding end 3 of the winding. This allows the gas formed in the air inlet 2 to act on the winding end 3, thereby cooling it. Through heat conduction, the entire winding end 3 is gradually cooled.

[0033] In this embodiment, several air inlets 2 are arranged circumferentially on the outer rotor housing 1. This arrangement can cool the entire circumferential direction, and at the same time, it can reduce noise during operation and ensure balanced stress.

[0034] In this embodiment, the outer rotor housing 1 has weight-reducing sections 4 on its side wall, the same number as the air inlets 2. All the weight-reducing sections 4 are arranged alternately with all the air inlets 2. This arrangement ensures mechanical strength and good heat dissipation. It improves heat dissipation without increasing the number of heat dissipation components or the internal structure of the motor.

[0035] In this embodiment, the air inlet 2 is a ventilation hole arranged radially along the outer rotor housing 1. The axis of the ventilation hole and the radial projection of the outer rotor housing 1 on the same virtual plane have a certain angle. The angle of attack of the air inlet of the ventilation hole faces the direction of rotation. The angle range is 40-60 degrees. 45 degrees is a preferred choice. By setting the ventilation hole and reasonably selecting the angle of attack, it is possible to ensure that airflow is formed radially along the outer rotor housing 1. This airflow is a low-temperature airflow entering the motor from the outside, directly acting on the winding end 3, ensuring the maximum cross-sectional area of ​​the ventilation hole and obtaining a better cooling effect. Through the above method, the weight of the outer rotor housing 1 can be reduced without adding any additional components. Radial cooling airflow is formed without relying on the addition of external components or external power, solving the heat dissipation problem of space constraints, weight constraints, and high heat generation under aviation conditions that has always been unresolved for outer rotor motors. Figure 1 and Figure 2 The design was applied to a 3.5kW external rotor generator with a speed of 4500rpm. It features six air inlets with a 45-degree inclination angle, and the air inlets are 5*12 rounded rectangles. Simulation results show that at the rated rotor speed, the radial airflow velocity generated by the radial-hole fan is 5.2m / s. Under rated conditions, the temperature of the motor stator windings can be reduced from 155 degrees Celsius without cooling to 115 degrees Celsius, demonstrating a significant improvement.

[0036] The sensors, controllers, and control programs mentioned above are all existing technologies and will not be elaborated upon.

[0037] The embodiments of the present invention disclosed above are merely illustrative of the present invention. The embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention.

Claims

1. A borehole-type self-cooling fan for an external rotor generator, characterized in that, include: The winding is located inside the outer rotor housing (1); The air inlet (2) is provided with several parts distributed on the periphery of the outer rotor housing (1) to form a radial airflow acting on the winding when the outer rotor housing (1) rotates.

2. A borehole-type self-cooling fan for an external rotor generator according to claim 1, characterized in that: The outer rotor housing (1) has a certain thickness.

3. A borehole-type self-cooling fan for an external rotor generator according to claim 2, characterized in that: The thickness is 4-6 mm.

4. A borehole-type self-cooling fan for an external rotor generator according to claim 1, characterized in that: The axial position of the air inlet (2) corresponds to the winding end (3) of the winding.

5. A borehole-type self-cooling fan for an external rotor generator according to claim 1, characterized in that: Several air inlets (2) are arranged in a circumferentially distributed manner on the peripheral wall of the outer rotor housing (1).

6. A borehole-type self-cooling fan for an external rotor generator according to claim 5, characterized in that: The outer rotor housing (1) has weight-reducing parts (4) on its side wall, the same number as the air inlet (2), and all the weight-reducing parts (4) are arranged alternately with all the air inlet (2).

7. A borehole-type self-cooling fan for an external rotor generator according to any one of claims 1-6, characterized in that: The air inlet (2) is a ventilation hole arranged radially along the outer rotor housing (1). The axis of the ventilation hole and the radial projection of the outer rotor housing (1) on the same virtual plane have a certain angle.

8. A borehole-type self-cooling fan for an external rotor generator according to claim 7, characterized in that: The air inlet of the ventilation hole faces the direction of rotation.

9. A borehole-type self-cooling fan for an external rotor generator according to claim 8, characterized in that: The angle of attack ranges from 40 to 60 degrees.

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