A lightweight axial cooling fan for AC transmission locomotives

Abstract

The present invention proposes a lightweight axial flow cooling fan for AC transmission locomotive, comprising a main ventilation duct, a non-metallic axial flow impeller, a multi-pole drive motor and a frequency converter combination, which can realize system integrated variable frequency speed control and lightweight; the main ventilation duct comprises: a mounting flange, an outer air duct, a front arc-shaped static blade, a guide hemisphere, an inner air duct and a circular arc-shaped guide static blade; the non-metallic axial flow impeller comprises a wing-shaped blade, a hub and a wheel core, and the blades and hub of the non-metallic axial flow impeller are made of glass fiber reinforced unsaturated polyester material; the rated speed of the multi-pole drive motor is 4500-5200rpm, the number of poles of the motor is greater than or equal to 4, the non-metallic axial flow impeller is connected to the rotating shaft of the multi-pole drive motor; the multi-pole drive motor is installed in the inner air duct of the main ventilation duct; the frequency converter is connected to the rear end cover of the multi-pole drive motor. The present invention has the advantages of being able to automatically adjust the air volume and pressure as needed, small appearance and interface size, light weight of the whole machine, and high heat dissipation efficiency.

Description

Technical Field

[0001] The present invention relates to the field of ventilation and cooling, and more specifically, to a lightweight axial flow cooling fan for an AC transmission locomotive. Background Art

[0002] Converters and transformers are one of the key equipment of rail transit AC transmission locomotives. When converters and transformers are working, a lot of heat will be generated inside them. In order to prevent overheating damage and ensure the normal operation of AC transmission locomotives, a matching cooling system is required to force heat dissipation of the converter. Axial flow cooling fans are an indispensable key component in the cooling system. In addition, with the increasing requirements for energy saving and reliability of rail transit, the requirements for lightweight and reliability of its equipment are getting higher and higher. There are three main methods for lightweight design technology of axial flow cooling fans. The first is to optimize the structure. At present, axial flow cooling fans all use thin-walled structures, and rail transit equipment has very high requirements for vibration and reliability. Therefore, under the existing axial flow cooling fans, the optimization space of the structure is small; the second is to use fiber composite materials instead of the original metal materials; the third is to use high-speed fans instead of low-speed fans, and the motor uses multi-pole motors instead of 2-pole motors, which can achieve the reduction of the overall volume of the fan and the reduction of the structural weight. For the reliability of axial flow cooling fans, in addition to controlling the structural vibration and strength of the fans, it is also necessary to control the speed of the axial flow cooling fans under different working conditions, so as to avoid the fans working at the rated speed for a long time, which is conducive to improving the reliability of the fans and realizing the intelligent control of the fans under different working conditions. At present, there are many studies on high-speed axial flow fans at home and abroad. High-speed magnetic suspension and air bearing compressors, such as CN109162940 A, CN 108716480 A and CN 104179712 A, are obviously different from the rolling bearing high-speed axial flow fans of this patent. For rolling shaft high-speed axial flow fans, CN 109555718 A mainly discloses a high-speed permanent magnet brushless axial flow fan, mainly studying the casing, stator, rotor and fan blades, focusing on the technical protection of permanent magnet motors; CN 107425634 A discloses an ultra-high-speed three-phase axial flow fan, mainly for the patent protection of the electromagnetic design of the motor.

[0003] At present, the axial flow cooling fan used in the cooling system of AC transmission locomotives is large in size, with a diameter of 1m and a weight of 360kg, which is difficult to meet the requirements of lightweight rail transportation equipment in the future. Based on this, a lightweight axial flow cooling fan integrating high speed, non-metallic materials, multi-pole motor and frequency conversion control is studied to meet the technical requirements of lightweight rail transportation equipment. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and design a lightweight axial flow cooling fan for AC transmission locomotives that has both lightweight characteristics and adjustable performance for heat dissipation in cooling towers of electric locomotives. The fan can be adjusted to achieve various flow pressures as required by changing the power frequency without replacing the hardware to meet the use requirements of different environmental conditions. The weight of the lightweight axial flow cooling fan for AC transmission locomotives of the present invention is reduced by 100kg compared with the original cooling system fan.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A lightweight axial flow cooling fan for an AC transmission locomotive, characterized in that it comprises a main ventilation duct (1) connected by flanges; the ventilation duct comprises an outer air duct (12) and an inner air duct (15); the main ventilation duct is provided with a mounting flange (11), a front arc-shaped stator blade (13), a guide hemisphere (14), a non-metallic axial flow impeller (2), and an arc-shaped guide stator blade (16) in sequence from an air inlet area to an air outlet area; a multi-pole drive motor (3) is installed in the inner air duct (15); and the multi-pole drive motor (3) is connected to the non-metallic axial flow impeller (2).

[0007] Furthermore, the front arc-shaped stationary blade (13) and the guide hemisphere (14) are welded together; and the front arc-shaped stationary blade (13) and the external air duct (12) are welded together.

[0008] Furthermore, the arc-shaped guide vane (16) is welded integrally with the outer air duct (12) and the inner air duct (15).

[0009] Furthermore, the blades of the non-metallic axial flow impeller (2) are twisted wing blades, and the impeller as a whole is manufactured and formed using glass fiber reinforced unsaturated polyester.

[0010] Furthermore, the twisted airfoil blades (21) of the non-metallic axial flow impeller are in a twisted airfoil shape, with an inlet arc radius of 2-2.5 mm, an outlet arc radius of 1.5-2 mm, a maximum blade thickness of 12 mm, a blade installation angle root of 42°-45°, and a top of 27°-30°. The hub (22) is in an arc shape with an arc radius of 110-118 mm.

[0011] Furthermore, the mounting flange (11), the front arc-shaped stationary blades (13), the guide hemisphere (14), and the arc-shaped guide stationary blades (16) are welded from alloy aluminum.

[0012] Furthermore, the central axes of the installation positions of the main air duct (12), the front arc-shaped stator blades (13), the guide hemisphere (14), the non-metallic axial flow impeller (2), and the arc-shaped guide stator blades (16) coincide with each other.

[0013] Furthermore, the front arc-shaped stationary blade (13) has an arc radius of 165-185 mm, and a hemispherical radius of the guide hemisphere is 105-115 mm.

[0014] Furthermore, the arc-shaped guide vane (16) has an arc radius of 249-269 mm, an inscribed arc radius of 110-120 mm, and an inscribed arc radius of 179-199 mm.

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) The present invention sets a frequency converter to convert the frequency of the power supply, and the multi-pole drive motor drives the non-metallic axial flow impeller to rotate. The power supply drive motor with different frequencies is used to adjust the impeller speed. The pressure, wind speed and flow rate generated by the present invention are adjustable. Under a certain structure and size, it can provide ventilation cooling flow and pressure for electric locomotive cooling towers with large flow and high pressure requirements; it can also reduce the overall size and weight as much as possible when designing while meeting different working conditions. The fan speed is 4500rpm to 5200rpm. Selecting this speed can use low-cost materials and control the fan noise to no more than 100dB (A). The fan noise is 3dB (A) lower than that of ordinary axial flow fans.

[0017] (2) The present invention determines the speed control mode of the fan inverter. The control temperature is the outlet temperature of the cooling tower radiator oil circuit. The control temperature is determined according to the ambient temperature and the oil circuit temperature. The control temperature determines the speed of the fan, and the speed is divided into 7 to 12 gears. Different ambient temperatures and oil circuit temperatures may select the same control temperature and fan speed. The switching of different gears is achieved by gradually raising and lowering the frequency of the inverter. After the control module determines the control temperature, it detects whether the actual temperature is consistent with the control temperature. If the actual temperature is higher than the control temperature, a digital signal is given to control the inverter to increase the frequency. If the actual temperature is lower than the control temperature, a digital signal is given to control the inverter to reduce the frequency. If the actual temperature is within the control temperature range, the speed is maintained stable. Therefore, the control temperature corresponding to the speed can be multi-polarly regulated in real time within the control gear.

[0018] (3) The frequency converter of the fan can be started to the corresponding frequency gear according to the power supply voltage and frequency, and then adjusted to the optimal gear according to the actual control temperature.

[0019] (4) The non-metallic axial flow impeller of the present invention is made of glass fiber reinforced unsaturated polyester to ensure that the components can work stably and reliably under high-speed operation conditions, and the service life can reach more than 10 years;

[0020] (5) The present invention is provided with front arc-shaped stator blades, guide hemispheres, and arc-shaped guide stator blades in the main ventilation duct. These structures are reasonably matched with the high-speed rotating impeller to guide the high-speed fluid to pass more smoothly, effectively reduce losses, improve the efficiency of the whole machine, and reduce the noise of the fan.

[0021] (6) The various components of the present invention are made of alloy aluminum materials with excellent performance, which reduces the weight of the entire machine and improves the heat dissipation capacity, ensuring that the temperature rise of the high-speed motor after miniaturization is lower than that of a motor with a normal speed.

[0022] (7) The multi-pole drive motor 2 used in the present invention has a casing made of cast aluminum alloy to improve heat dissipation capacity. By adopting a multi-pole solution, the weight of the entire machine and the weight of the rotor are reduced, thereby improving the life and reliability of the fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of a lightweight axial-flow cooling fan for an AC transmission locomotive of the present invention;

[0024] Figure 2 This is a schematic diagram of the main ventilation duct structure;

[0025] Figure 3 It is a schematic diagram of the structure of a non-metallic axial flow impeller;

[0026] Figure 4 This is a schematic diagram of the front arc-shaped stationary blade structure;

[0027] Figure 5 Schematic diagram of the arc-shaped guide vane structure.

[0028] Figure numerals: 1 main ventilation duct, 2 non-metallic axial flow impeller, 3 multi-pole drive motor, 4 inverter, 11 mounting flange, 12 external air duct, 13 front arc-shaped stator blades, 14 guide hemisphere, 15 internal air duct, 16 arc-shaped guide stator blades, 21 blades, 22 hub, 23 wheel core. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The accompanying drawings are only for illustrative purposes and are only schematic diagrams, not actual drawings, and cannot be understood as limiting the present patent; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; it is understandable to those skilled in the art that some well-known structures and their descriptions in the accompanying drawings may be omitted.

[0030] Example 1

[0031] like Figure 1As shown, the present invention provides a lightweight axial flow cooling fan for an AC transmission locomotive, comprising a main ventilation duct formed by connecting a large mounting flange; wherein the main ventilation duct comprises an outer air duct 12 and an inner air duct 15; the main ventilation duct is provided with front arc-shaped stator blades 13, a guide hemisphere 14, a non-metallic axial flow impeller 2, and arc-shaped guide stator blades 16 in sequence from the air inlet area to the air outlet area, and the central axes of the installation positions of the various components coincide.

[0032] A multi-pole drive motor 3 is installed in the inner auxiliary ventilation duct. The multi-pole drive motor 3 is connected to the non-metallic axial flow impeller 2 through a rotating shaft. The speed output by the multi-pole drive motor 3 can be adjusted by a frequency converter 4, so the speed of the non-metallic axial flow impeller 2 driven by the multi-pole drive motor 3 is adjustable, and the pressure, wind speed and flow rate of the fluid generated by the non-metallic axial flow impeller 2 can all change according to the change of the speed of the non-metallic axial flow impeller 2. The specific structure of the non-metallic axial flow impeller 2 is as follows: Figure 3 shown.

[0033] The front curved stationary blades 13 are welded to the guide hemisphere 14 as a whole, and the front curved stationary blades are welded to the outer air duct 12 to ensure the installation rigidity and reduce the vibration during operation. The front curved stationary blades 13 ensure that the airflow gradually transitions from being parallel to the axis to being consistent with the inlet angle of the impeller blades, so that the airflow enters the impeller inlet with basically no loss. The specific structure of the front curved stationary blades 13 is as follows: Figure 3 shown.

[0034] The arc-shaped guide vanes 16 are arranged between the outer air duct 12 and the inner air duct 15 and are welded to the two. Under the premise of ensuring the overall strength and rigidity, the arc-shaped guide vanes are made of alloy aluminum to achieve lightweight and better heat dissipation. The arc-shaped guide vanes 16 gradually transition the angle between the airflow and the fan axis from about 20 degrees to close to 0 degrees. The airflow enters the cooling tower radiator that needs heat dissipation more smoothly at the outlet, thereby improving the efficiency of the whole machine. The specific structure of the arc-shaped guide vanes 16 is as follows: Figure 4 shown.

[0035] Based on the above structure, the specific working mode of the present invention is as follows:

[0036] The new high-speed axial flow fan for the cooling tower of an AC-driven electric locomotive in the present invention is used for ventilation and cooling of the locomotive cooling tower. The low-temperature airflow enters the front air duct of the fan from the filter grid on the top of the locomotive, and after being guided by the front arc-shaped stator blades and the guide hemisphere, the airflow enters the impeller at a certain angle. After the impeller rotates at high speed, the airflow speed and pressure are greatly increased, and then thrown out to the external air duct, and after being guided by the arc-shaped guide stator blades, it enters the high-temperature aluminum heat dissipation structure of the cooling tower along the axis. In this structure, the temperature in the aluminum radiator is transferred to the air, so that the air temperature rises, and the high-temperature air flows out of the cooling tower with the airflow and enters the atmosphere at the bottom of the locomotive, achieving a cooling effect.

[0037] The mounting flange 11, the outer air duct 12, the front arc-shaped static vanes 13, the guide hemisphere 14, the inner air duct 15 and the arc-shaped static vanes 16 in the present invention can be made of alloy aluminum materials of different models with excellent welding performance according to different use requirements, which can reduce the weight of the whole machine and improve the heat dissipation capacity.

[0038] The non-metallic axial flow impeller 2 adopts different glass fiber reinforced unsaturated polyester materials according to the rotational speed requirements. The blades are twisted wing blades and the impeller is integrally formed. When the rotational speed is lower than 4000r / min, general glass fiber reinforced unsaturated polyester can be used. When the rotational speed is 4000r / min to 5000r / min, high-strength glass fiber reinforced unsaturated polyester can be used. The impeller with a rotational speed greater than 5000r / min should adopt a higher strength material. The inverter drives the multi-pole motor, and the casing is made of cast aluminum alloy to improve the heat dissipation capacity. By adopting a multi-pole solution, the weight of the whole machine and the rotor weight are reduced, and the life and reliability of the fan are improved.

[0039] Example 2

[0040] Compared with Example 1, this embodiment provides a non-metallic axial flow impeller 2 with a twisted airfoil shape, an inlet arc radius of 2mm, an outlet arc radius of 1.5mm, a maximum blade thickness of 12mm, a blade installation angle root of 42°, and a top of 27°. This specification of airfoil blade impeller can provide a large amount of air and pressure, and runs smoothly with high efficiency. The claims of the present invention include an inlet arc radius of 2-2.5mm, an outlet arc radius of 1.5-2mm, a maximum blade thickness of 12mm, a blade installation angle root of 42°~45°, and a top of 27°~30°. The hub (22) is in an arc shape with an arc radius of 110-118mm.

[0041] Compared with Example 2, this embodiment provides a front arc-shaped stationary blade, whose arc radius is 175 mm and the hemispherical radius of the guide hemisphere is 111 mm.

[0042] Compared with Example 2, this embodiment provides an arc-shaped guide vane, whose arc radius is 259 mm, the inscribed arc radius is 115 mm, and the inscribed arc radius is 189 mm.

[0043] Example 3

[0044] As shown in Table 1, the present invention provides a control mode for a lightweight axial flow cooling fan for an AC transmission locomotive, which is controlled according to different use environment conditions. According to different combinations of ambient temperature, cooling tower water temperature and oil temperature, different speeds are set, and the fan provides different pressures and flows.

[0045] Ambient temperature ° Water channel temperature° Oil circuit temperature° Control temperature° Fan speed rpm -40~-20 1 27 50~55 2000~2500 -20~10 31 57 60~65 2500~3000 10~30 51 77 80~85 3500~4500 30~40 61 87 90~95 4500~5200 -40~-20 1 17 40~45 1500~2000 -20~10 21 37 50~55 2000~2500 10~30 41 57 60~65 2500~3000 30~40 51 67 70~75 3000~3500 -40~-20 1 7 30~35 1500 -20~10 11 27 40~45 1500~2000 10~30 31 47 50~55 2000~2500 30~40 41 57 60~65 2500~3000

[0046] The control temperature of the fan is the outlet temperature of the cooling tower radiator oil circuit. The control temperature is determined according to the ambient temperature and the oil circuit temperature. The control temperature determines the speed of the fan, and the speed is divided into seven gears. Different ambient temperatures and oil circuit temperatures may choose the same control temperature and fan speed. The switching of different gears is achieved by gradually raising and lowering the frequency of the inverter. After the control module determines the control temperature, it detects whether the actual temperature and the control temperature are combined. If the actual temperature is higher than the control temperature, a digital signal is given to control the inverter to increase the frequency. If the actual temperature is lower than the control temperature, a digital signal is given to control the inverter to reduce the frequency. The actual temperature is within the control temperature range to maintain a stable speed. Therefore, the speed corresponding to the control temperature can be adjusted in real time within the control gear. See Table 1 for specific control parameters.

[0047] Obviously, the above examples are only examples for clearly illustrating the technical solutions of the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. Lightweight axial flow cooling fan for AC transmission locomotive, characterized by: The invention comprises a main ventilation duct (1), a non-metallic axial flow impeller (2), a multi-pole drive motor (3) and a frequency converter (4), wherein the main ventilation duct (1) comprises: a mounting flange (11), an outer air duct (12), a front arc-shaped static blade (13), a guide hemisphere (14), an inner air duct (15) and a circular arc-shaped guide static blade (16); the non-metallic axial flow impeller comprises wing-shaped blades (21), a hub (22) and a wheel core (23), and the blades (21) and the hub (22) of the non-metallic axial flow impeller (2) are made of glass fiber reinforced unsaturated polyester material; the non-metallic axial flow impeller (2) is connected to the rotating shaft of the multi-pole drive motor (3); the multi-pole drive motor (3) is installed in the inner air duct (15) of the main ventilation duct (1); and the frequency converter (4) is connected to the rear end cover of the multi-pole drive motor (3); The front arc-shaped static blade (13) is arranged between the guide hemisphere (14) and the outer air duct (12), and is welded to the two. The circular arc-shaped static blade (16) is arranged between the outer air duct (12) and the inner air duct (15), and is welded to the two. The mounting flange (11), the front arc-shaped static blade (13), the guide hemisphere (14), and the circular arc-shaped static blade (16) are welded from aluminum alloy. The front arc-shaped static blade (13) has an arc radius of 165-185 mm, and the hemispherical radius of the guide hemisphere (14) is 105-115 mm; the arc-shaped static blade (16) has an arc radius of 249-269 mm, and the inscribed arc radius is 110-120 mm; The blades (21), the hub (22) and the wheel core (23) of the non-metallic axial flow impeller (2) are integrally molded; the blades (21) and the hub (22) use chopped glass fibers as reinforcement materials, which are uniformly mixed with an unsaturated polyester resin or epoxy resin matrix to form a quasi-isotropic material system; the wheel core (23) uses cast aluminum or cast iron material; The blade (21) is in a twisted airfoil shape, with an inlet arc radius of 2-2.5 mm, an outlet arc radius of 1.5-2 mm, a maximum blade thickness of 12 mm, a blade installation angle of 42°-45° at the root and 27°-30° at the top, and a hub (22) in an arc shape with an arc radius of 110-118 mm; The rated speed of the multi-pole drive motor (3) is 4500-5200 rpm, and the number of poles of the motor is greater than or equal to 4, which helps to reduce the size and weight of the motor.

2. The axial flow cooling fan according to claim 1, characterized in that: The main ventilation duct (1) is provided with front arc-shaped static blades (13), a guide hemisphere (14), a non-metallic axial flow impeller (2), and arc-shaped guide static blades (16) in sequence from the air inlet area to the air outlet area.

3. The axial flow cooling fan according to claim 2, characterized in that: The central axes of the installation positions of the main ventilation duct (1), the front arc-shaped static blades (13), the guide hemisphere (14), the non-metallic axial flow impeller (2), and the arc-shaped static blades (16) coincide with each other.

4. The axial flow cooling fan according to claim 1, characterized in that: The frequency converter (4) speed control adopts 7 to 12 gears to control the speed of the motor according to the ambient temperature, water circuit temperature and oil circuit temperature, thereby better improving the reliability of the axial flow cooling fan while meeting the cooling conditions of different working conditions.

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