Combined type axial flow self-cooling fan structure for outer rotor starter generator

Abstract

The utility model provides a combined type axial flow self-cooling fan structure for an outer rotor generator, and belongs to the field of machinery. The problem that the outer rotor motor of the aviation starter cannot effectively dissipate heat is solved. A plurality of air holes are formed in the side wall of the outer rotor shell. And the fan blade assembly is coupled with the plurality of air holes and is used for rotating along with the outer rotor shell to form airflow flowing along the axial direction of the outer rotor shell. The cooling device is mainly used for cooling motor stators.

Description

Technical Field

[0001] This utility model belongs to the field of machinery, and in particular relates to a composite axial flow self-cooling fan structure 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. During startup, it absorbs energy from the battery to generate torque, driving the engine to start and run 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 high-torque startup time is short, and the longest operating period for the starter-generator is in generator mode. Furthermore, due to application environment constraints, starter-generators must be small in size and light in weight, operating 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 5 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.

[0004] Meanwhile, some civilian motor technologies have straight blades on the inner wall of the outer rotor. The resulting gas flow direction is along the radial direction of the outer rotor housing, and it flows directly away along the weight reduction process holes, which cannot form effective heat dissipation. For stator components, the most important thing is to form airflow along its axial direction to complete heat dissipation. At the same time, under the premise of limited space, the existing technology still cannot effectively solve the heat dissipation problem of high load and high heat generation of external rotor motors in aviation. Utility Model Content

[0005] In view of this, the present invention aims to propose a composite axial flow self-cooling fan structure for an external rotor starter generator, so as to solve the problem that the external rotor motor of an aircraft starter generator cannot effectively dissipate heat.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: a composite axial flow self-cooling fan structure for an external rotor generator, comprising:

[0007] The outer rotor housing has several air vents on its side walls;

[0008] The fan blade assembly, coupled with several air vents, is used to generate airflow along the axial direction of the outer rotor housing as it rotates.

[0009] Furthermore, the air vents are opened along the axial direction.

[0010] Furthermore, the number of air vents is 4-10 and they are evenly arranged.

[0011] Furthermore, the shape of the air vent is a regular geometric shape, a composite geometric shape, and / or an irregular geometric shape.

[0012] Furthermore, the outer rotor housing perimeter wall within a predetermined distance from the fan blade assembly side is a blind plate structure.

[0013] Furthermore, the fan blade assembly is provided with a plurality of blades, the blades having a predetermined angle of attack and matching the rotation direction of the outer rotor housing.

[0014] Furthermore, the fan blade assembly also includes a blade support portion connected to the blade and fixed to the corresponding air hole by a fixing portion.

[0015] Furthermore, the angle of attack is 45 degrees.

[0016] Furthermore, the number of blades is 1-3.

[0017] Furthermore, the fan blade assembly is made of plastic or carbon fiber material and has a certain axial length.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] 1. This self-cooling fan structure, by setting air vents instead of traditional weight-reduction vents, can effectively reduce the weight of the outer rotor housing while forming a channel for air flow, thus creating the prerequisite for the flow of heat dissipation air.

[0020] 2. This self-cooling fan structure uses the coupling of the fan blade assembly and the air vents, and through a distributed arrangement, it can form an axial flow of gas that directly acts on the stator to achieve heat dissipation. The directional flow of gas will not be lost along the way, resulting in good heat dissipation. At the same time, the distributed layout can avoid the defect of limited space in aircraft external rotor starters and generators, which cannot form an effective heat dissipation structure. Attached Figure Description

[0021] 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:

[0022] Figure 1 This is a cross-sectional view of a composite axial flow self-cooling fan structure for an external rotor generator according to the present invention.

[0023] Figure 2 This is a schematic diagram showing the distribution of the air holes on the outer rotor housing of this utility model;

[0024] Figure 3 The present utility model Figure 2 A sectional view;

[0025] Figure 4 This is a three-dimensional structural diagram of the wind turbine assembly described in this utility model;

[0026] Figure 5 This is a schematic diagram of an existing external rotor motor.

[0027] 1. Outer rotor housing; 2. Fan blade assembly; 2-1. Blade support; 2-2. Blade; 2-3. Fixing part; 3. Air hole. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Referring to the accompanying drawings, this embodiment describes a composite axial flow self-cooling fan structure for an external rotor generator, characterized by comprising:

[0032] The outer rotor housing 1 has several air holes 3 on its side wall; the air holes 3 are arranged in a circumferentially evenly distributed manner, which allows airflow to pass through while reducing the overall weight of the outer rotor housing 1.

[0033] The fan blade assembly 2, coupled with several air vents 3, is used to generate airflow along the axial direction of the outer rotor housing 1 as it rotates. 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. The extra components increase the overall weight, thus creating a major challenge for cooling methods. The purpose of the fan blade assembly 2 is to coordinate with the air vents 3 in a distributed manner, effectively solving the problem of limited installation space. Simultaneously, the coordination between the air vents 3 and the fan blade assembly 2 creates an axial airflow, effectively cooling the stator and removing heat. This avoids the shortcomings of most existing technologies that can only generate radial airflow along the weight-reduction holes, failing to effectively cool the stator.

[0034] In this embodiment, the air vent 3 is opened along the axial direction. The air vent 3 serves two main purposes: weight reduction and providing an airflow source for cooling. The core purpose of the fan assembly 2 is to generate axial airflow for cooling; therefore, opening the air vent 3 axially allows for the most direct and effective introduction of gas, reduces wind resistance, and enhances the cooling effect.

[0035] In this embodiment, the number of air vents 3 is 4-10 and they are evenly arranged. This number is a suitable choice and can be optimized according to the size of the casing.

[0036] In this embodiment, the shape of the air vent 3 is a regular geometric shape, a composite geometric shape, and / or an irregular geometric shape. Specifically, the shape of the air vent 3 is selected as a quasi-rectangular hole. A quasi-rectangular hole provides a certain aesthetic effect, is easy to process, and facilitates assembly. The rounded corners reduce installation resistance and airflow resistance. In terms of airflow rate, a quasi-rectangular hole can achieve a larger airflow volume for the same area; therefore, it is chosen. Of course, other types of openings can be selected according to actual needs and reasonable deformation. In such cases, the shape of the corresponding fan blade assembly 2 needs to be adjusted accordingly. Other opening types are still within the spirit of this utility model application.

[0037] In this embodiment, the outer rotor housing 1 has a blind plate structure within a predetermined distance from the fan blade assembly 2 on its peripheral wall. This arrangement ensures that the airflow fully cools the stator during axial flow, preventing airflow from overflowing before it has been adequately cooled, thus guaranteeing sufficient cooling of the stator. The predetermined distance can be reasonably set according to the axial length of the stator.

[0038] In this embodiment, the fan blade assembly 2 is provided with a plurality of blades 2-2, each blade 2-2 having a predetermined angle of attack and matching the rotation direction of the outer rotor housing 1. An angle of attack of 45 degrees is a common choice, but other angles of attack can be set according to actual needs, limitations of the thickness of the fan blade assembly 2, etc. It is important to note that the rotation direction of the outer rotor housing 1 must match the angle of attack so that the fan blade assembly 2 can drive the gas to form an axial flow for cooling when rotating. The distributed blades 2-2, on the one hand, can form an axial flow through the angle of attack, and on the other hand, the installation method in conjunction with the air vents 3 can solve a long-standing problem in related fields, namely the space limitation problem of aircraft generators: due to the limited internal space, for some special motor structures, the internal windings need to be encapsulated, which brings great challenges to space utilization and heat dissipation. In this case, it is impossible to install traditional axial flow blades inside or outside, so the heat dissipation problem under this condition has not been well solved. This structure, by setting up distributed blades 2-2, does not require additional space. Through its organic integration with the air vents 3, it can achieve axial gas formation and flow, ultimately achieving excellent heat dissipation. This solves the long-standing heat dissipation problem in the field of aero-engine generators.

[0039] In this embodiment, the fan blade assembly 2 further includes a blade support portion 2-1, which is connected to the blade 2-2 and fixed to the corresponding air hole 3 via a fixing portion 2-3. The blade support portion 2-1 is mainly designed to provide support for the blade 2-2 and can cooperate with the air hole 3 to complete the overall fixation of the fan blade assembly 2. Specifically, the blade support portion 2-1 is designed to be stepped in the axial direction, which allows it to engage with the air hole 3. An opening is provided at an appropriate position on the end face as a fixing portion 2-3. The blade support portion 2-1 is fixed to the outer rotor housing 1 by screws engaging with the opening. The cross-sectional shape of the blade support portion 2-1 needs to be consistent with the air hole 3 to facilitate better fixation and reduce noise and cavitation caused by gas turbulence.

[0040] In this embodiment, the number of blades 2-2 is 1-3. The number of blades 2-2 in a single fan blade assembly 2 should be reasonably selected according to the actual situation. Too many blades 2-2 will affect the air flow. 1-3 is a more suitable choice. The appropriate selection can be made according to the specific heat dissipation conditions.

[0041] In this embodiment, the fan blade assembly 2 is made of plastic or carbon fiber and has a certain axial length. It can be produced using 3D printing or mold pressing, with weight reduction as the primary focus. In the aerospace environment, weight is strictly controlled, so the overall quality of the fan blade assembly 2 needs to be rigorously controlled. Plastic or carbon fiber are good choices, but other low-weight, high-strength, and heat-resistant materials can also be used in this application, still within the spirit of this utility model. Regarding the axial length setting of the fan blade assembly 2 or blade 2-2, since the outer wall thickness of a typical casing is only about 3mm, the composite fan blade must be designed as a one-piece shell to ensure its strength.

[0042] During operation, the outer rotor housing 1 rotates with the main shaft. This rotation drives the distributed fan blade assembly 2 to rotate as well. Because the blades 2-2 within the fan blade assembly 2 have an angle of attack with the incoming airflow, they propel the gas, creating an axial airflow. As the gas flows past the stator, it carries away heat, aiding in stator cooling. In existing technologies, due to the specific operating conditions and structural characteristics of aircraft generators, it is impossible to add extra blades and cooling structures to the shaft or internal space. This application innovatively employs distributed blades and uses weight-reduction holes as air vents. This organic combination overcomes the limitation of insufficient space for blade installation and effectively creates an axial airflow, solving the problem of high heat generation under high loads in aircraft generators without effective active cooling.

[0043] This structure was applied to a 3kW external rotor starter-generator operating at 4500rpm. Five air vents were designed, with two blades in each composite fan blade configuration, and the axial length of the blades was 9mm. In actual testing, at the rated rotor speed, the axial airflow velocity generated by the composite fan blades reached 6.2m / s. With the cooling provided by the composite fan blades, the temperature of the motor stator windings decreased from 155 degrees Celsius (without cooling) to 110 degrees Celsius, demonstrating a significant cooling effect and ensuring reliability for aerospace applications.

[0044] The sensors, controllers, and control programs mentioned above are all existing technologies and will not be elaborated upon.

[0045] 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 composite axial flow self-cooling fan structure for an external rotor generator, characterized in that, include: The outer rotor housing (1) has several air holes (3) on its side wall; The fan blade assembly (2) is coupled with several air holes (3) to form an airflow along the axial direction of the outer rotor housing (1) as the outer rotor housing (1) rotates.

2. The composite axial flow self-cooling fan structure for an external rotor generator according to claim 1, characterized in that: The air vent (3) is opened along the axial direction.

3. A composite axial self-cooling fan structure for an external rotor generator according to claim 1 or 2, characterized in that: The number of air holes (3) is 4-10 and they are evenly arranged.

4. A composite axial flow self-cooling fan structure for an external rotor generator according to claim 3, characterized in that: The shape of the air vent (3) is a regular geometric shape and / or a composite geometric shape.

5. A composite axial flow self-cooling fan structure for an external rotor generator according to claim 1, characterized in that: The outer rotor housing (1) has a blind plate structure within a predetermined distance from the fan blade assembly (2) on its peripheral wall.

6. A composite axial self-cooling fan structure for an external rotor generator according to claim 1, 2, 4 or 5, characterized in that: The fan blade assembly (2) is provided with a number of blades (2-2), the blades (2-2) having a predetermined angle of attack and matching the rotation direction of the outer rotor housing (1).

7. A composite axial flow self-cooling fan structure for an external rotor generator according to claim 6, characterized in that: The wind turbine assembly (2) also includes a blade support part (2-1), which is connected to the blade (2-2) and fixed to the corresponding wind hole (3) by a fixing part (2-3).

8. A composite axial flow self-cooling fan structure for an external rotor generator according to claim 6, characterized in that: The angle of attack is 45 degrees.

9. A composite axial flow self-cooling fan structure for an external rotor generator according to claim 6, characterized in that: The number of blades (2-2) is 1-3.

10. A composite axial self-cooling fan structure for an external rotor generator according to claim 6, characterized in that: The fan blade assembly (2) is made of plastic or carbon fiber material and has a certain axial length.

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