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

Abstract

The invention 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] The invention belongs to the field of machinery, and in particular relates to a composite axial flow self-cooling fan structure for an outer rotor generator. Background Art

[0002] Starter systems are increasingly being used in small and medium-sized aircraft. The starter system's function is to work in conjunction with the aircraft engine. During the starting process, it draws energy from the battery, generating torque to start the engine and drive it to cold-running speed. After starting, the engine burns gasoline or diesel at high speed, and its shaft drives the motor rotor to generate electricity. The motor windings output three-phase AC power, which is rectified by the starting controller into DC power to charge the battery or output it. Of these two states, the generator mode provides high torque and short starting time, with the starter operating the longest. Furthermore, due to the constraints of the application environment, the starter must be small, lightweight, and operate at high power density. Therefore, long-term safe and reliable operation in the generator mode is a key performance characteristic of the starter system and a key concern for users.

[0003] The most important factor that determines the long-term safe operation of the motor is the cooling condition. If the cooling is not sufficient, the stator winding will continue to heat up and exceed the insulation limit and burn out. In order to facilitate assembly, most existing starters are designed as an outer rotor assembly structure, such as Figure 5 In such a structure, the heat-generating stator components are inside the motor, which is not conducive to heat dissipation. Due to limited space, it is impossible to set up a fan to provide cooling for the stator components. Therefore, improving the cooling conditions on the motor itself becomes the best solution.

[0004] At the same time, some civilian motor technologies set straight blades on the inner wall of the outer rotor. The gas flow direction formed by them is along the radial direction of the outer rotor shell, and will flow directly along the weight-reducing process holes, which cannot form effective heat dissipation. For the stator component, the most important thing is to form an airflow along its axial direction to complete the heat dissipation. At the same time, under the premise of limited space, the existing technology still cannot effectively solve the heating problem of high-load and high-heat outer rotor motors in aviation. Summary of the Invention

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

[0006] To achieve the above object, the present invention adopts the following technical solution: a composite axial flow self-cooling fan structure for an outer rotor generator, comprising:

[0007] The outer rotor casing has a number of air holes on its side wall;

[0008] The fan blade assembly is coupled with a plurality of wind holes and is used to rotate with the outer rotor casing to form an airflow flowing along the axial direction of the outer rotor casing.

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

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

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

[0012] Furthermore, the peripheral wall of the outer rotor casing is a blind plate structure within a predetermined distance from the wind blade assembly side.

[0013] Furthermore, a plurality of blades are provided in the fan blade assembly, and the blades have a predetermined angle of attack and match the rotation direction of the outer rotor casing.

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

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

[0016] Furthermore, the number of the 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 present invention has the following beneficial effects:

[0019] 1. This self-cooling fan structure replaces the traditional weight-reducing holes by setting air holes, which can effectively reduce the weight of the outer rotor casing and form a channel for gas flow, forming a prerequisite for the flow of heat dissipation gas;

[0020] 2. This self-cooling fan structure couples the fan blade assembly with the air holes, and through a distributed layout, can form an axial flow of gas that directly acts on the stator to complete heat dissipation. The directional flow of gas will not be lost along the way, and the heat dissipation effect is good. At the same time, through the distributed layout, it can avoid the defect that the space of the aviation outer rotor generator is limited and cannot form an effective heat dissipation structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0022] Figure 1A cross-sectional view of a composite axial flow self-cooling fan structure for an outer rotor generator according to the present invention;

[0023] Figure 2 This is a schematic diagram of the distribution positions of the air holes on the outer rotor housing according to the present invention;

[0024] Figure 3 The present invention Figure 2 sectional view of

[0025] Figure 4 This is a schematic diagram of the three-dimensional structure of the fan blade assembly according to the present invention;

[0026] Figure 5 Schematic diagram of an external rotor motor in the prior art.

[0027] Outer rotor housing 1; fan blade assembly 2; blade bearing portion 2-1; blade 2-2; fixing portion 2-3; air hole 3. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features therein can be combined with each other in the absence of conflict, and the embodiments described are only part of the embodiments of the present invention, not all of the embodiments.

[0029] It should be noted that the descriptions of the present invention regarding directions such as "left", "right", "left side", "right side", "upper", "lower", "top", and "bottom" are all defined based on the relationship between the orientations or positions shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure described must be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0030] In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0031] Referring to the accompanying drawings, this embodiment is described, which is a composite axial flow self-cooling fan structure for an outer rotor generator, characterized in that it includes:

[0032] The outer rotor housing 1 is provided with a plurality of air holes 3 on its side wall. The air holes 3 are evenly distributed around the circumference, which allows air to pass through while reducing the weight of the entire outer rotor housing 1 .

[0033] The fan blade assembly 2 is coupled with a plurality of air holes 3, and is used to rotate with the outer rotor housing 1 to form an airflow that flows axially along the outer rotor housing 1. In the aviation field, the weight of any component has a huge impact on the overall weight. Many components need to be installed on the shaft of the outer rotor motor. At the same time, some processing methods require the winding to be packaged, which poses a great challenge to the internal space. The redundant components will lead to an increase in the overall weight, thus posing a great challenge to the cooling method. The purpose of setting up the fan blade assembly 2 is to cooperate with the air holes 3 in a distributed form, which just solves the problem of limited installation space. At the same time, through the cooperation between the air holes 3 and the fan blade assembly 2, an axial flow of air is formed, which effectively cools the stator and takes away heat. It avoids the defect that most of the existing technologies can only form radial airflow that flows along the weight-reducing holes and cannot effectively cool the stator.

[0034] In this embodiment, the air holes 3 are axially oriented. The air holes 3 serve two primary purposes: weight reduction and providing a source of airflow for cooling. The core purpose of the fan assembly 2 is to generate axial airflow for cooling. Therefore, axially oriented air holes 3 allow for the most direct and efficient introduction of air, reducing wind resistance and enhancing cooling.

[0035] In this embodiment, the number of the air holes 3 is 4-10 and they are evenly arranged. This number is a more appropriate choice and can be optimized and determined according to the size of the housing.

[0036] In this embodiment, the shape of the air hole 3 is a regular geometric shape, a composite geometric shape and / or an irregular geometric shape. Specifically, the shape of the air hole 3 is selected to be a quasi-rectangular hole. Quasi-rectangular holes can bring a certain aesthetic effect and are easy to process. At the same time, this shape is conducive to assembly. Setting certain rounded corners on the four corners is conducive to reducing the resistance of installation and the resistance of gas flow. In terms of air intake flow angle, quasi-rectangular holes can obtain a larger air intake volume under the condition of equal area, so quasi-rectangular holes are selected. Of course, other types of opening forms can also be selected according to actual needs and reasonable deformations. Then the corresponding shape of the fan blade assembly 2 needs to be adjusted accordingly according to the opening form. Other types of openings are still within the inventive spirit of this application.

[0037] In this embodiment, a blind plate structure is provided within a predetermined distance from the outer rotor housing 1's circumferential wall near the fan blade assembly 2. This arrangement ensures that the airflow fully cools the stator during axial flow, preventing airflow from overflowing before sufficient cooling has occurred, thereby ensuring adequate cooling of the stator. The predetermined distance can be appropriately set based on the axial length of the stator.

[0038] In this embodiment, the fan assembly 2 is provided with a plurality of blades 2-2, each having a predetermined angle of attack that matches the direction of rotation of the outer rotor housing 1. A 45-degree angle of attack is a common choice, but a corresponding angle of attack can also be set based on actual needs, limitations on the thickness of the fan assembly 2, and other factors. It should also be noted that the direction of rotation of the outer rotor housing 1 must match the angle of attack, so that the fan assembly 2 can propel the air to form an axial flow for cooling during rotation. Distributed blades 2-2, on the one hand, can form an axial flow through the angle of attack, and on the other hand, when installed in conjunction with the air holes 3, can solve a problem that has long plagued the relevant field, namely, the limited space of aircraft generators. Due to the limited and cramped internal space, some special motor structures require the internal windings to be encapsulated, which poses a significant challenge to both space utilization and heat dissipation. In this case, traditional axial flow blades cannot be installed internally or externally, making the heat dissipation problem under these conditions difficult to solve. This structure, by distributing blades 2-2, does not require additional space. By organically combining blades 2-2 with air holes 3, it can achieve axial gas formation and flow, ultimately achieving good heat dissipation, thus solving the long-standing heat dissipation problem in the field of aviation generators.

[0039] In this embodiment, the fan blade assembly 2 further includes a blade bearing portion 2-1, which is connected to the blade 2-2 and fixed to the corresponding wind hole 3 via a fixing portion 2-3. The blade bearing portion 2-1 is provided mainly to provide support for the blade 2-2 and to cooperate with the wind hole 3 to complete the fixation of the fan blade assembly 2 as a whole. Specifically, the blade bearing portion 2-1 is provided in a stepped shape in the axial direction so that it can be engaged in the wind hole 3 through the step, and an opening is provided at an appropriate position on the end surface as the fixing portion 2-3. The blade bearing portion 2-1 is fixed to the outer rotor housing 1 by screws in cooperation with the opening. The cross-sectional shape of the blade bearing portion 2-1 needs to be consistent with the wind hole 3 to facilitate better fixation and reduce the noise and cavitation effects 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 assembly 2 is selected reasonably according to actual conditions. Too many blades 2-2 will affect the air flow. 1-3 is a more appropriate choice. A reasonable selection can be made according to specific heat dissipation conditions.

[0041] In this embodiment, the fan blade assembly 2 is made of plastic or carbon fiber material and has a certain axial length. It can be produced by 3D printing or mold compression molding, and the most important thing is to reduce weight. In the aviation environment, there is strict control over weight, so for the fan blade assembly 2 as a whole, the quality needs to be strictly controlled. Plastic or carbon fiber is a better choice. Of course, other low-weight, high-strength, and heat-resistant materials can also be used in this application, which is still within the spirit of the invention of this application. As for the setting of the axial length of the fan blade assembly 2 or the blade 2-2, since the thickness of the outer wall of the general casing is only about 3 mm, the composite fan blade should be designed as an integrated shell to ensure the strength of the fan blade.

[0042] During use, the outer rotor housing 1 will rotate along with the main shaft, and the outer rotor housing 1 will drive the distributed fan blade assembly 2 to rotate. Since the blades 2-2 in the fan blade assembly 2 have an angle of attack with the incoming air, they can push the gas to form an axial flow airflow. When the gas flows through the stator, it takes away the heat and helps the stator to dissipate heat. In the prior art, due to the specific operating conditions and structural characteristics of the aviation generator, it is impossible to add extra blades and heat dissipation structures on the shaft and the internal space. The present application innovatively adopts distributed blades and uses the weight-reducing holes as wind holes. The organic combination of the two overcomes the defect of having no space to install blades, and effectively forms an axial flow airflow, solving the problem that the high load of the aviation generator easily leads to high heat but cannot effectively and actively dissipate heat.

[0043] This structure was applied to a 3kW external rotor generator with a rotational speed of 4500 rpm. Five air holes were designed, with two blades in each composite fan blade, each with an axial length of 9 mm. In actual testing, the composite fan blades generated an axial airflow velocity of 6.2 m / s at the rated speed of the motor rotor. With the cooling provided by the composite fan blades, the temperature of the motor stator windings was reduced from 155 degrees Celsius without cooling measures to 110 degrees Celsius. This significant cooling effect ensures reliability under aerospace operating conditions.

[0044] In the above description, the sensors, controllers and control programs that may be involved are all existing technologies and will not be described in detail.

[0045] The embodiments of the present invention disclosed above are intended only to illustrate the present invention. The embodiments do not describe all details in detail, nor do they limit the present invention to the specific embodiments described. Numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification 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 outer rotor generator, characterized in that: include: The outer rotor housing (1) has a plurality of air holes (3) provided on its side wall; The fan blade assembly (2) is coupled with a plurality of wind holes (3) and is used to rotate with the outer rotor casing (1) to form an airflow flowing along the axial direction of the outer rotor casing (1).

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

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

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

5. The composite axial flow self-cooling fan structure for an outer rotor generator according to claim 1, characterized in that: The peripheral wall of the outer rotor casing (1) is provided with a blind plate structure within a predetermined distance on the side close to the wind blade assembly (2).

6. A composite axial flow self-cooling fan structure for an outer rotor generator according to claim 1, 2, 4 or 5, characterized in that: A plurality of blades (2-2) are arranged in the fan blade assembly (2), and the blades (2-2) have a predetermined angle of attack and match the rotation direction of the outer rotor casing (1).

7. The composite axial flow self-cooling fan structure for an outer rotor generator according to claim 6, characterized in that: The fan blade assembly (2) also includes a blade bearing 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).

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

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

10. The composite axial flow self-cooling fan structure for an outer 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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