Rail transit system based on linear induction motor

Abstract

The invention provides a rail transit system based on a linear induction motor. The rail transit system comprises a rail, a squirrel-cage secondary part, a linear motor primary part, wheels, a vehicle frame and a compartment. The squirrel-cage secondary stage is mounted at the bottom of the track; the linear motor primary is located below the squirrel-cage secondary; the wheels are in primary connection with the linear motor through the vehicle frame, and the wheels are used for moving on the track; the compartment is mounted on the vehicle frame. Compared with the prior art, the rail transit system based on the linear induction motor has the advantages that the stability of motor operation can be better guaranteed, and the safety of train operation is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of rail transit technology, and in particular to a rail transit system based on a linear induction motor. Background Art

[0002] At present, in rail transit, the power of the vehicle is usually generated by the rotating motor. When the vehicle is running on a climbing section, its climbing ability is restricted by the adhesion coefficient, and it will produce large mechanical vibration and noise. At the same time, the maximum speed of the wheel-rail vehicle will also be limited. The advent of the maglev train truly realizes the contact-free, friction-free and wear-free operation between the vehicle and the ground, effectively overcoming the drawbacks of the traditional wheel-rail vehicle operation, and is very suitable for the development of large and medium-sized cities with large and medium-sized traffic.

[0003] Linear motors are usually used to drive maglev trains, and linear induction motors have the advantages of simple structure, small thrust fluctuation, and low cost, so they have become the preferred motor for linear motor urban rail transit systems. At present, urban rail transit systems using linear induction motors, especially linear motors and medium and low-speed maglev train systems, have been widely used.

[0004] However, when the linear induction motor in the prior art is used for a long time, foreign matter is easily accumulated on the secondary surface or contaminated by ferromagnetic foreign matter, which affects the control parameters and affects the safety of train operation. Summary of the invention

[0005] Aiming at the technical problem that when linear induction motors in the prior art are used for a long time, the secondary surface is prone to accumulate foreign matter or be contaminated by ferromagnetic foreign matter, which affects the control parameters and affects the safety of train operation. The present invention provides a rail transit system based on a linear induction motor, which installs the secondary at the bottom of the track and sets the primary below the secondary, and inverts the setting positions of the secondary and the primary, which can better avoid the accumulation of foreign matter on the secondary, thereby better avoiding the impact of foreign matter on the secondary, and ensuring the stability of motor operation and the safety of train operation.

[0006] A rail transit system based on a linear induction motor comprises a track, a squirrel cage secondary, a linear motor primary, wheels, a vehicle frame, and a carriage;

[0007] The squirrel cage secondary is mounted on the bottom of the track;

[0008] The linear motor primary is located below the squirrel cage secondary;

[0009] The wheel is connected to the primary of the linear motor through the vehicle frame, and the wheel is used to move on the track;

[0010] The carriage is mounted on the vehicle frame.

[0011] Preferably, the squirrel cage type secondary includes a cast structure secondary device, and the cast structure secondary device includes a secondary back iron and a secondary conductor bar;

[0012] The secondary conductor bar is cast on the secondary back iron.

[0013] Preferably, a casting groove is provided in the secondary back iron, and a casting port is provided at the top of the secondary back iron, and the casting port is connected to the casting groove;

[0014] The secondary conductive bar includes a main body portion located within the casting trough and an extended portion located outside the casting trough.

[0015] Preferably, the secondary conductive bar is a secondary aluminum conductive bar.

[0016] Preferably, the casting trough has a trapezoidal cross-section.

[0017] Preferably, the casting trough has a rectangular cross-section.

[0018] Preferably, the casting trough comprises a first trough body, a second trough body and a connecting trough body;

[0019] The first trough body is in communication with the casting port;

[0020] The second slot body is located at the lower side of the first slot body and is connected to the first slot body through the connecting slot body;

[0021] The groove cross-sections of the first groove body and the second groove body are both circular.

[0022] Preferably, the width of the groove-shaped cross-section of the casting groove gradually decreases from a side close to the casting port to a side away from the casting port.

[0023] Preferably, the casting groove is arranged through both sides of the secondary back iron.

[0024] Preferably, a plurality of the casting troughs are provided, and the plurality of the casting troughs are arranged in sequence and at intervals.

[0025] Preferably, the secondary back-iron is made of laminated silicon steel sheets.

[0026] Compared with the prior art, the rail transit system based on a linear induction motor provided by the present invention includes a track, a squirrel cage secondary, a linear motor primary, wheels, a vehicle frame, and a carriage; the squirrel cage secondary is installed at the bottom of the track; the linear motor primary is located below the squirrel cage secondary; the wheel is connected to the linear motor primary through the vehicle frame, and the wheel is used to move on the track; the carriage is installed on the vehicle frame. In the rail transit system based on a linear induction motor, since the squirrel cage secondary is installed at the bottom of the track and the linear motor primary is located below the squirrel cage secondary, it is inverted compared with the existing method. This structure avoids the accumulation of ferromagnetic pollutants on the secondary, such as iron filings, iron blocks, etc., and also avoids the accumulation of foreign matter on the secondary, such as stones, etc. The accumulation of ferromagnetic materials will change the equivalent electromagnetic air gap of the motor, change the motor parameters, affect the motor control accuracy, and reduce the motor performance. The accumulation of foreign matter will also impact the primary core and winding, causing damage to the motor. Therefore, the rail transit system based on the linear induction motor provided by the present invention effectively solves the above problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the structure of a rail transit system based on a linear induction motor provided by an embodiment;

[0029] Figure 2 for Figure 1 A schematic structural diagram of a rail transit system based on a linear induction motor from another angle is shown;

[0030] Figure 3 A schematic diagram of the structure of a secondary device of a casting structure provided in an embodiment;

[0031] Figure 4 A schematic diagram of a cross-sectional structure of a secondary back iron provided in an embodiment;

[0032] Figure 5 A schematic cross-sectional structure diagram of a secondary back iron provided in another embodiment;

[0033] Figure 6 A schematic cross-sectional structure diagram of a secondary back iron provided in another embodiment;

[0034] Figure 7A schematic cross-sectional structure diagram of a secondary back iron provided in another embodiment;

[0035] Figure 8 A schematic diagram of the structure of a secondary conductor bar provided in an embodiment;

[0036] Fig. 9 A schematic diagram of the structure of a secondary conductor bar provided in an embodiment;

[0037] Fig.10 A schematic diagram of the structure of a secondary conductor bar provided in an embodiment;

[0038] Fig.11 A schematic structural diagram of a secondary conductive bar provided in an embodiment. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] It should be noted that when a component is referred to as being "fixed on", "installed on" or "set on" another component, it can be directly on the other component or indirectly set on the other component; when a component is "connected" to another component, or a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component.

[0041] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" and "several" mean two or more, unless otherwise clearly and specifically defined.

[0043] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions under which this application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by this application.

[0044] The present invention provides a rail transit system based on a linear induction motor, which includes a track, a squirrel cage secondary, a linear motor primary, a wheel, a vehicle frame, and a carriage; the squirrel cage secondary is installed at the bottom of the track; the linear motor primary is located below the squirrel cage secondary; the wheel is connected to the linear motor primary through the vehicle frame, and the wheel is used to move on the track; the carriage is installed on the vehicle frame. In the rail transit system based on the linear induction motor, since the squirrel cage secondary is installed at the bottom of the track and the linear motor primary is located below the squirrel cage secondary, it is inverted compared with the existing method. Through this structure, the accumulation of ferromagnetic pollutants on the secondary, such as iron filings, iron blocks, etc., is avoided, and the accumulation of foreign matter on the secondary, such as stones, etc., is also avoided. The accumulation of ferromagnetic materials will change the equivalent electromagnetic air gap of the motor, change the motor parameters, affect the motor control accuracy, and reduce the motor performance. The accumulation of foreign matter will also impact the primary iron core and winding, causing damage to the motor. Therefore, the rail transit system based on the linear induction motor provided by the present invention effectively solves the above problems.

[0045] Please refer to Figure 1 and Figure 2 The present embodiment provides a rail transit system 100 based on a linear induction motor, which is used to solve the problem in the prior art that foreign matter is easily accumulated on the secondary surface, thereby affecting the motor and affecting the safety of train operation.

[0046] The rail transit system 100 based on a linear induction motor includes a track 10, a squirrel cage secondary 20, a linear motor primary 30, a wheel 40, a vehicle frame 50, and a car 60. The squirrel cage secondary 20 is installed at the bottom of the track 10, and the linear motor primary 30 is located below the squirrel cage secondary 20. The wheel 40 is connected to the linear motor primary 30 through the vehicle frame 50, and the wheel 40 is used to move on the track 10. The car 60 is installed on the vehicle frame 50. When the rail transit system 100 based on a linear induction motor is working, the linear motor primary 30 generates a traveling wave magnetic field, and the traveling wave magnetic field is induced in the squirrel cage secondary 20. The two magnetic fields interact with each other to push the car 60 to achieve the forward or backward movement of the vehicle.

[0047] Different from existing linear motors and vehicles driven by linear motors, the linear motor secondary used in the linear induction motor-based rail transit system 100 provided in this embodiment is a squirrel cage secondary, and the electromagnetic air gap of the motor is reduced, thereby improving the thrust density, efficiency and power factor of the motor.

[0048] It is understandable that in the existing rail transit system, the primary of the motor is installed under the car body, while the secondary is installed on the track and located below the primary, which makes it easy for foreign matter to accumulate on the secondary surface or be contaminated by ferromagnetic foreign matter, affecting the control parameters and the safety of train operation. For example, when ferromagnetic foreign matter such as iron filings and iron blocks accumulate on the secondary surface, it will change the equivalent electromagnetic air gap of the motor, change the motor parameters, affect the motor control accuracy, and reduce the motor performance; when foreign matter such as stones accumulate on the secondary surface, the accumulation of foreign matter will also hit the primary iron core and winding, causing damage to the motor.

[0049] In the rail transit system 100 based on the linear induction motor provided in this embodiment, since the squirrel cage secondary 20 is installed at the bottom of the track 10, the linear motor primary 30 is located below the squirrel cage secondary 20, which is an inverted structure compared to the prior art, thereby effectively avoiding the accumulation of foreign matter on the secondary, solving the above-mentioned problem.

[0050] Furthermore, in the prior art, an ice-water mixture will accumulate on the secondary induction plate in low-temperature rainy and snowy weather. When the motor is running, the secondary will generate heat, and the ice and snow will melt into water due to the heat. When the motor passes through the primary, the secondary will no longer generate heat, and the temperature will drop, which will cause ice to form a vicious cycle.

[0051] The linear induction motor-based rail transit system 100 provided by the present invention is an inverted structure. When the primary passes through the secondary, the melted water will flow down and will not accumulate on the secondary surface. Therefore, it will not be affected by rain, snow or freezing weather and has strong environmental adaptability.

[0052] Please refer to Figure 3 Preferably, in one embodiment, the squirrel cage type secondary 20 includes a cast structure secondary device 21, and the cast structure secondary device 21 includes a secondary back iron 22 and a secondary conductor bar 23, and the secondary conductor bar 23 is cast on the secondary back iron 22. The squirrel cage type secondary 20 may include a plurality of the cast structure secondary devices 21 arranged in sequence.

[0053] It is understandable that the secondary, as a part of the linear motor, is usually a composite secondary plate, which consists of an induction plate and a back iron. Its main function is to generate an induced current and interact with the primary traveling wave magnetic field to generate thrust. Therefore, the material and structure of the secondary have a certain influence on the characteristics of the motor. In order to further improve the performance of the motor, many scholars at home and abroad have also carried out many studies in this regard. For example, the induction plate adopts a grid-type, V-type, W-type and other structures to reduce the edge effect and reduce the secondary eddy current loss, but these structures are all for the induction plate. In addition, the composite secondary plate needs to be processed by an extremely complex explosion welding process, and different structures are processed on the secondary induction plate, which requires a lot of time and labor costs. In the rail transit system 100 based on the linear induction motor provided in this embodiment, a structure is proposed to cancel the secondary induction plate, slot and cast on the secondary back iron, which is not only simple in structure and processing, but also can effectively weaken the end effect, reduce the secondary eddy current loss, and improve the efficiency of the motor.

[0054] Please refer to Figure 4 and Figure 8 . Preferably, in one embodiment, a casting groove 221 is provided in the secondary back iron 22, and a casting port 222 is provided at the top of the secondary back iron 22, and the casting port 222 is connected to the casting groove 221, and the casting port 222 can facilitate the casting of molten metal. The secondary guide bar 23 includes a main body 231 located in the casting groove 221 and an extension portion 232 located outside the casting groove 221. When manufacturing the secondary device 21 of the casting structure, a customized tooling can be used, and the customized tooling is formed into the required shape of the extension portion 232, and then the molten metal is poured in for cooling, and finally the secondary guide bar 23 is manufactured. It can be understood that in order to ensure safe operation, the linear motor needs to maintain a large air gap between the primary and the secondary, so a large excitation current is required, which leads to low efficiency of the motor and difficulty in increasing thrust. In the secondary device 21 of the casting structure provided in this embodiment, the casting groove 221 is opened on the secondary back iron, the shape of the protruding part 232 is surrounded by a customized tooling, and after pouring the molten metal and cooling, the secondary guide bar 23 is finally obtained, and finally a new type of secondary device of the casting structure is formed. This structure is conducive to weakening the end effect, reducing the secondary eddy current loss, and improving the efficiency and thrust of the motor.

[0055] Specifically, in one embodiment, the secondary conductor bar 23 is a secondary aluminum conductor bar. That is, the secondary conductor bar 23 is cast by aluminum liquid. During preparation, the secondary back iron 22 is surrounded by a custom tooling to form a desired shape, and then aluminum liquid is poured into the casting trough 221 and the custom tooling to cool, thereby producing the secondary aluminum conductor bar.

[0056] Preferably, in one embodiment, the casting groove 221 has a trapezoidal cross section, such as Figure 4 As shown, specifically, the upper bottom of the trapezoid is located on a side close to the casting port 222. Correspondingly, the main body 231 obtained by casting through the casting trough 221 is also trapezoidal, as shown in FIG. Figure 8 shown.

[0057] Preferably, in one embodiment, the casting groove 221 has a rectangular cross section. Figure 5 Correspondingly, the main body 231 obtained by casting through the casting trough 221 is also rectangular, as shown in FIG. Fig. 9 shown.

[0058] Please refer to Figure 6 . Preferably, in one embodiment, the casting trough 221 includes a first trough body 2211, a second trough body 2212 and a connecting trough body 2213. The first trough body 2211 is connected to the casting port 222, the second trough body 2212 is located at the lower side of the first trough body 2211, and the second trough body 2212 is connected to the first trough body 2211 through the connecting trough body 2213. The trough cross-sections of the first trough body 2211 and the second trough body 2212 are both circular. That is, in this embodiment, the casting trough 221 as a whole is two circular structures connected up and down. Please refer to Fig.10 Correspondingly, the main body 231 obtained by casting through the casting groove 221 also presents two circular structures connected up and down. Specifically, the main body 231 includes a first main body 2311, a second main body 2312 and a connecting body 2313. The second main body 2312 is located at the lower side of the first main body 2311, and the second main body 2312 is connected to the first main body 2311 through the connecting body 2313.

[0059] Please refer to Figure 7 Preferably, in one embodiment, the width of the groove section of the casting groove 221 gradually decreases from the side close to the casting port 222 to the side away from the casting port 222, that is, the casting groove 221 as a whole presents a "pear-shaped" structure that is wide at the top and narrow at the bottom. Fig.11 Correspondingly, the main body 231 cast through the casting trough 221 also presents a "pear-shaped" structure that is wide at the top and narrow at the bottom.

[0060] Preferably, the casting groove 221 is provided through both sides of the secondary back iron 22. Thus, both sides of the main body 231 obtained by casting are connected with the extension part 232, so that the secondary conductive bar 23 obtained by casting finally forms an integral part.

[0061] Preferably, in one embodiment, a plurality of casting grooves 221 are provided, and the plurality of casting grooves 221 are arranged in sequence and at intervals, so that the secondary conductive bar 23 correspondingly includes a plurality of the main body parts 231 which are arranged in sequence and at intervals.

[0062] Preferably, in one embodiment, the secondary back iron 22 is made of laminated silicon steel sheets.

[0063] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A rail transit system based on a linear induction motor, It is characterized in that Includes tracks, squirrel cage secondary, linear motor primary, wheels, vehicle frame, and carriage; The squirrel cage secondary is mounted on the bottom of the track; The linear motor primary is located below the squirrel cage secondary; The wheel is connected to the primary of the linear motor through the vehicle frame, and the wheel is used to move on the track; The carriage is mounted on the vehicle frame.

2. The rail transit system based on a linear induction motor according to claim 1, It is characterized in that The squirrel cage type secondary includes a cast structure secondary device, and the cast structure secondary device includes a secondary back iron and a secondary conductor bar; The secondary conductor bar is cast on the secondary back iron.

3. The rail transit system based on the linear induction motor according to claim 2, It is characterized in that A casting groove is provided in the secondary back iron, and a casting port is provided at the top of the secondary back iron, and the casting port is connected to the casting groove; The secondary conductive bar includes a main body portion located within the casting trough and an extended portion located outside the casting trough.

4. The rail transit system based on the linear induction motor according to claim 3, It is characterized in that The secondary conductive bars are secondary aluminum conductive bars.

5. The rail transit system based on the linear induction motor according to claim 3, It is characterized in that The casting trough has a trapezoidal cross section.

6. The rail transit system based on a linear induction motor according to claim 3, It is characterized in that The casting trough has a rectangular cross section.

7. The rail transit system based on a linear induction motor according to claim 3, It is characterized in that The casting trough comprises a first trough body, a second trough body and a connecting trough body; The first trough body is in communication with the casting port; The second slot body is located at the lower side of the first slot body and is connected to the first slot body through the connecting slot body; The groove cross-sections of the first groove body and the second groove body are both circular.

8. The rail transit system based on a linear induction motor according to claim 3, It is characterized in that The width of the groove-shaped cross section of the casting groove gradually decreases from the side close to the casting port to the side far away from the casting port.

9. The rail transit system based on a linear induction motor according to claim 3, It is characterized in that The casting groove is arranged through both sides of the secondary back iron.

10. The rail transit system based on a linear induction motor according to claim 3, It is characterized in that There are multiple casting grooves, and the multiple casting grooves are arranged in sequence at intervals.

11. The rail transit system based on a linear induction motor according to claim 3, It is characterized in that The secondary back iron is made of laminated silicon steel sheets.

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