Railway wagon shaft end generator and power generation system

Abstract

The invention provides a railway wagon shaft end generator and a power generation system, and relates to the technical field of railway wagon generators. According to the invention, the stator is arc-shaped and mounted on the adapter or the side frame above the shaft end, and the rotor is gear-shaped and circular and mounted at the shaft end, so that a split structure in which the stator and the rotor are separately mounted is formed. Furthermore, a permanent magnet is arranged on a stator, two U-shaped iron cores of the stator fixedly clamp the permanent magnet, when the gear-shaped rotor rotates along with an axle, rotor teeth and U-shaped stator grooves and teeth move relatively, and the magnetic resistance of a magnetic circuit and the magnetic circuit change accordingly, so that the magnetic flux penetrating through a stator winding and the direction of the magnetic field change, and the magnetic flux and the direction of the magnetic field are changed. The stator winding generates alternating induced potential, and when a winding external circuit is closed, alternating induced current is generated, so that power generation of the generator is realized. The stator is supported by the adapter or the side frame, the rotor is supported by the axle, the stator and the rotor are of mutually independent split structures, friction pieces such as bearings are not arranged, the structure is simple, the requirement for the structural strength of a fixed installation part of the generator is reduced, reliability is improved, and maintenance cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of railway wagon generators, and particularly to an axle-end generator and a power generation system for railway wagons. Background Art

[0002] In the operation scenario of railway wagons, power generation is crucial for the stable power supply of on-vehicle intelligent systems. Through advanced power generation technologies, such as axle-end power generation devices, the mechanical energy during the operation of wagons can be converted into electrical energy, providing continuous and reliable power supply for on-vehicle intelligent systems. This not only ensures the stable operation of various sensors, communication devices, data processing modules, etc. in the intelligent system, facilitating the real-time monitoring of information such as the operation status of wagons and the condition of goods, but also lays a solid foundation for the realization of functions such as intelligent brake control and fault warning, greatly improving the intelligent level and safety of railway wagon transportation.

[0003] Existing generators generally include a cylindrical stator and a cylindrical rotor, and the stator and the rotor are rotatably connected through bearings arranged at both ends of the axle. Usually, permanent magnets are installed on the rotor, and windings are wound on the stator. When the rotor rotates inside the stator, it drives the magnetic field to rotate, and the changing magnetic field generates an induced electromotive force in the stator winding.

[0004] For existing railway wagon axle-end generators, generally, existing motors are directly installed at the axle end. Due to the particularity of railway wagons, during operation, the interaction between the track and the wheels causes strong vibrations, especially the continuous jumping of the axle. To avoid the influence of vibrations on the generator, one existing method is to fix the generator stator to the bogie, and the rotor is connected to the axle through a coupling. This method increases the coupling and has a complex structure, and moreover, the length of the center of gravity of the motor extending outward along the axle is too large, and the fixed part of the stator is extremely easy to break during severe vibrations, with low reliability. Another existing method is to fixedly connect the rotor to the axle, and the stator is not connected to the vehicle body and only has a limited rotation amplitude. This method does not increase the coupling, but the overall weight of the motor is borne by the axle, requiring a high connection strength between the rotor and the axle, and is also prone to breakage due to severe vibrations, with low reliability. In addition, on the one hand, the generator bearings are in a vibrating environment for a long time, resulting in increased wear and also low reliability; on the other hand, the heat generated during the operation of the generator increases the temperature rise of the bearings due to heat radiation. Summary of the Invention

[0005] Embodiments of the present invention provide an axle-end generator and a power generation system for railway wagons to solve the problem that existing railway wagon axle-end generators are easily damaged and have low reliability in a vibrating environment.

[0006] In a first aspect, embodiments of the present invention provide an axle-end generator for railway wagons, including: a rotor and a stator;

[0007] The rotor and the stator are respectively installed and fixed independently; the rotor is used to be installed at the axle end of a railway freight car and rotates with the axle; the stator is in the shape of an arc with a central angle less than 180 degrees and is used to be fixedly installed around the rotor on the bolster or side frame above the axle end.

[0008] The rotor is a rotor core with a gear-shaped radial cross-section.

[0009] The stator includes i stator cores and i - 1 permanent magnets. Among them, any permanent magnet is fixedly connected to two adjacent stator cores. The radial cross-section shape of the stator core is a U-shaped groove; the U-shaped opening of any stator core faces the rotor.

[0010] One winding is correspondingly arranged for any permanent magnet. The winding passes through the inside of two adjacent U-shaped grooves and is arranged around the permanent magnet; the magnetic poles of the permanent magnet are parallel to the rotation direction of the axle. Among them, the stator cores on both sides of the permanent magnet and two adjacent rotor teeth form the main magnetic path passing through the winding.

[0011] When the axle drives the rotor to rotate, the generator is used to make the rotor teeth and the stator U-shaped groove teeth have relative motion, the magnitude of the magnetic reluctance of the magnetic path and the magnetic path change accordingly, so that the magnetic flux and the magnetic field direction passing through the stator winding change, and an alternating induced electromotive force is generated in the stator winding. When the external circuit of the winding is closed, an alternating induced current is generated to achieve power generation.

[0012] In a possible implementation manner, in the arc-shaped stator, the central angle of the permanent magnet, the central angle of the stator core U-shaped groove teeth, and the central angle of the stator core U-shaped groove opening are all the same as the central angle of the rotor teeth.

[0013] The central angle between two adjacent rotor teeth is the sum of the central angle of the arc-shaped stator core and the central angle of the permanent magnet. Among them, when the relative area between any rotor tooth and any stator U-shaped groove tooth is the largest, the magnetic flux passing through the winding is the largest; when the relative area between any rotor tooth and any stator U-shaped groove opening is the largest, the magnetic flux passing through the winding is the smallest.

[0014] For any stator core, when the rotor teeth move from the first U-shaped groove tooth of the stator core to the second U-shaped groove tooth respectively, the magnetic field direction passing through the winding changes.

[0015] In a possible implementation manner, the stator includes at least two stator cores and one permanent magnet.

[0016] In a possible implementation manner, the number of teeth P of the rotor is determined based on the following formula:

[0017] P = 60 * f ÷ n

[0018] Wherein, f is the target power generation frequency of the generator, with the unit of hertz; n is the rotational speed of the wheel set of the railway freight car at the target running speed, with the unit of revolutions per minute.

[0019] In a possible implementation manner, the winding is a single-coil winding corresponding to each permanent magnet; multiple single-coil windings are connected in series or in parallel according to the electromagnetic characteristics of the generator and the requirements of external electrical equipment.

[0020] In a possible implementation manner, it further includes a protective cover; the protective cover is fixedly connected to the stator together; the protective cover is arranged on the side of the stator and the rotor away from the shaft end; the projection of the protective cover towards the shaft end covers the stator and the rotor.

[0021] In a possible implementation manner, the installation gap between the stator and the rotor is determined based on the installation tolerances of the rotor and the stator and the design requirements of the generator air gap.

[0022] In a possible implementation manner, it further includes a heat-insulating protective layer; the heat-insulating protective layer is arranged on the side of the stator close to the axle bearing.

[0023] In a possible implementation manner, insulating layers are arranged on the surfaces of the stator and the rotor.

[0024] In a second aspect, an embodiment of the present invention provides a railway freight car axle-end power generation system, including the railway freight car axle-end generator in any of the above possible implementation manners.

[0025] An embodiment of the present invention provides a railway freight car axle-end generator and a power generation system. By setting the stator as an arc shape and installing it on the bolster or side frame above the axle end, and the rotor as a gear-shaped circle and installing the rotor on the axle end, a split structure with the stator and the rotor separately installed is formed. Further, by arranging permanent magnets on the stator and fixing the two U-shaped iron cores of the stator to clamp the permanent magnets, when the gear-shaped rotor rotates with the axle, relative movements occur between the rotor teeth and the U-shaped stator slots and teeth of the stator, the magnetic reluctance and the magnetic circuit of the magnetic circuit change accordingly, so that the magnetic flux and the magnetic field direction passing through the stator winding change, and an alternating induced electromotive force is generated in the stator winding. When the external circuit of the winding is closed, an alternating induced current is generated to realize power generation of the generator. The stator of the present invention is supported by the bolster or side frame, and the rotor is supported by the axle. The stator and the rotor are independent split structures. There are no friction parts such as bearings, the structure is simple, the structural strength requirements for the fixed installation part of the generator are reduced, the reliability is improved, and the maintenance cost is reduced.

[0026] Moreover, when the axle of the vehicle bounces up and down during operation, the arc-shaped stator on the bearing saddle above the axle can be separated from the rotor, avoiding collision between the stator and the rotor and improving reliability. When the axle is overhauled and the bearing saddle and the axle are separated, the arc-shaped stator can be automatically separated from the rotor without additional disassembly of the generator, improving the efficiency of axle overhaul. Brief Description of the Drawings

[0027] Figure 1 is a schematic structural diagram of the axle-end generator of a railway freight car provided by an embodiment of the present invention;

[0028] Figure 2 is a schematic diagram of the magnetic circuit in the first rotational position provided by an embodiment of the present invention;

[0029] Figure 3 is a schematic diagram of the magnetic circuit in the second rotational position provided by an embodiment of the present invention;

[0030] Figure 4 is a schematic diagram of the magnetic circuit in the third rotational position provided by an embodiment of the present invention;

[0031] Figure 5 is a schematic diagram of the magnetic circuit in the fourth rotational position provided by an embodiment of the present invention;

[0032] Figure 6 is a schematic diagram of the magnetic circuit in the fifth rotational position provided by an embodiment of the present invention;

[0033] Figure 7 is a schematic structural diagram of another axle-end generator of a railway freight car provided by an embodiment of the present invention;

[0034] Figure 8 is provided by an embodiment of the present invention Figure 7 Schematic structural diagram of the A-A cross-section in. Detailed Embodiments

[0035] In order to enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below in conjunction with the drawings in the embodiments of this solution. Obviously, the described embodiments are some, but not all, of the embodiments of this solution. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this solution without creative efforts shall fall within the scope of protection of this solution.

[0036] The term "including" in the description and claims of this solution and the above-mentioned drawings, as well as any other variations, means "including but not limited to", intending to cover non-exclusive inclusion and not limited to the examples listed in the text. In addition, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order.

[0037] The implementation of the present invention will be described in detail with reference to the specific drawings as follows:

[0038] Railway freight trains generally include locomotives and multiple railway freight cars. The formation of railway freight trains changes frequently. By adopting the self-power generation method of railway freight cars, each car has independent power generation ability and does not need to rely on the cable connection between cars to obtain power. No matter how the cars are formed, they can independently supply power to the on-vehicle intelligent system, avoiding the problem of power supply line adjustment caused by formation changes and improving the flexibility and adaptability of the operation of railway freight cars.

[0039] Axle-end power generation of railway freight cars is one of the self-power generation methods of railway freight cars. Existing axle-end generators of railway freight cars usually use the mechanical energy during the operation of railway freight cars as the power source. For example, the rotor is connected to the freight car axle through the axle end, and the rotation of the freight car axle drives the rotation of the generator rotor to realize the transmission of mechanical energy. The rotation of the rotor makes its magnetic field move relative to the stator winding, and then an induced electromotive force is generated. In the case where the stator winding is closed, an induced current will be formed, realizing the conversion from mechanical energy to electrical energy to supply power to equipment such as the on-vehicle intelligent system.

[0040] The structure of the existing axle-end generator of railway freight cars will be described first. Existing generators usually include a cylindrical stator and a cylindrical rotor, and the stator and rotor are rotationally connected through motor bearings arranged at both ends of the axle. The function of the motor bearings is to support the stator and the rotor. When the rotor rotates inside the stator, since there are permanent magnets installed on the rotor or a magnetic field generated by an excitation winding, the magnetic field rotates along with the rotation of the rotor. And the stator is wound with windings. According to the law of electromagnetic induction, a changing magnetic field will generate an induced electromotive force in the stator winding. Specifically, the rotation of the rotor causes the magnetic flux passing through the stator winding to change, and the rate of change of the magnetic flux determines the magnitude of the induced electromotive force.

[0041] During the operation of railway freight cars, due to the unevenness of the track surface (such as the existence of joints, wear, depressions, weld protrusions, etc.), when the wheels contact the track, a large impact force will be generated, which will cause the wheels to bounce up and down and swing laterally during driving. This kind of vibration will not only affect the running smoothness of the vehicle, but also accelerate the wear and damage of the axle-end generator. For example, the wear of the motor bearings, the fracture of the motor fixed connection, etc.

[0042] Specifically, the motor bearings bear the stator and the rotor. During frequent and intense vibrations, the impact force on the motor bearings is relatively large, leading to increased wear. The motor is fixedly suspended outside on the axle end of the car body, and the fixed position is at the connection between the motor and the axle end. The force received at the fixed position is related to the total weight of the motor and the overhanging length of the center of gravity of the motor outward. The heavier the motor, the greater the force received at the fixed position. The more outward the center of gravity of the motor is, the greater the force received at the fixed position. Also, due to the intense vibrations during the operation of railway freight cars, the force received at the fixed position is further increased, making it extremely prone to fracture, with low reliability, short service life, large maintenance volume, and high cost.

[0043] The axle generator for railway freight cars provided by an embodiment of the present invention simplifies the structure, reduces the overall weight, disperses the weight, reduces the installation strength requirements, and improves the reliability through a bearingless split-type motor.

[0044] Figure 1 It is a schematic structural diagram of an axle generator for railway freight cars provided by an embodiment of the present invention. Refer to Figure 1 , this generator includes: the rotor and the stator are respectively independently installed and fixed; the rotor is used to be installed on the axle end of the railway freight car and rotates with the axle; the stator is a circular arc with a central angle less than 180 degrees and is used to surround the rotor and be fixedly installed on the bolster or side frame above the axle end; the rotor is a rotor core with a gear-shaped radial cross-section; the stator includes i stator cores and i - 1 permanent magnets, where any one permanent magnet is fixedly connected to two adjacent stator cores, and the radial cross-section shape of the stator core is a U-shaped groove; the U-shaped opening of any stator core faces the rotor; a winding is correspondingly arranged for any one permanent magnet, and the winding passes through the inside of two adjacent U-shaped grooves and surrounds the permanent magnet; the magnetic poles of the permanent magnet are parallel to the rotation direction of the axle; among them, the stator cores on both sides of the permanent magnet and two adjacent rotor teeth form a main magnetic path passing through the winding; when the axle drives the rotor to rotate, the generator is used to make the rotor teeth and the stator U-shaped groove teeth have relative movement, the magnetic reluctance of the magnetic path and the magnetic path change accordingly, so that the magnetic flux and the magnetic field direction passing through the stator winding change, and an alternating induced electromotive force is generated in the stator winding. When the external circuit of the winding is closed, an alternating induced current is generated to achieve power generation.

[0045] In some embodiments, the axle generator for railway freight cars includes a rotor and a stator. Exemplarily, the generator is of a split-type structure. Here, the split-type structure means that there is no support between the rotor and the stator, for example, no bearing connection is required. The following specifically describes the structures of the rotor and the stator to illustrate how the rotor and the stator ensure the realization of the power generation function without a motor bearing.

[0046] In some embodiments, the rotor and the stator are used for independent installation and fixation respectively; the rotor is used for being installed at the axle end of a railway freight car and rotates with the axle; the stator is in an arc shape with a central angle less than 180 degrees and is used for being fixedly installed around the rotor on a bolster or a side frame above the axle end.

[0047] It should be noted that the separate installation and fixation means that the rotor and the stator are respectively fixed at different positions.

[0048] Exemplarily, the rotor is used for being installed at the axle end of a railway freight car. Further, the rotor is fixedly connected to the axle end. For example, three screw holes can be provided on the rotor and fixed to the axle end based on the 3 bolts for fixing the bearing end cover in the prior art. Exemplarily, when the axle rotates, the rotor can rotate together with the axle.

[0049] Exemplarily, the stator is used for being fixedly installed around the rotor on a bolster or a side frame above the axle end. Moreover, the stator is in an arc shape with a central angle less than 180 degrees. Further, after the motor is installed, the centers of the stator and the rotor coincide with the center of the axle, and a predetermined gap is provided between the stator and the rotor.

[0050] In a possible implementation manner, the installation gap between the stator and the rotor is determined based on the installation tolerances of the rotor and the stator and the design requirements of the generator air gap.

[0051] It should be noted that the gap between the stator and the rotor can be determined by the manufacturing and installation tolerances of the three axle end bolts of the bearing front cover and the manufacturing and installation tolerances of the stator and the rotor. For example, the installation gap between the stator and the rotor does not exceed 10 millimeters. That is, after installation, the gap between the stator and the rotor does not exceed 10 millimeters.

[0052] The bolster and the side frame are relatively fixed. Hereinafter, the installation will be described taking the bolster as an example.

[0053] It should be noted that the bolster is located between the side frame and the axle of a railway freight car bogie, is mounted on the axle neck of the axle from above the axle, and is an important component connecting the side frame and the axle. It is usually in a saddle shape, and its shape and size match the axle neck of the axle and the corresponding parts of the side frame to achieve a tight and stable connection. Correspondingly, the arc-shaped stator is fixedly installed on the bolster, and thus is installed above the rotor. Further, it should be noted that here the stator is in an arc shape with a central angle less than 180 degrees. On the one hand, it can avoid the collision between the stator and the rotor in a vibration environment and improve the reliability. On the other hand, it can facilitate the disassembly and assembly of the axle and improve the maintenance efficiency.

[0054] Regarding the first aspect, in a railway wagon, the relative movement amplitude between the bearing saddle and the axle is small, and the movement modes may include the separating movement and the approaching movement in the up-and-down direction. During the separating movement, the distance between the bearing saddle and the axle increases, and the distance between the stator and the rotor also increases. Since the stator is not circular but small semi-circular arc-shaped, the distance between the stator and the rotor will only increase and will not collide. During the approaching movement, the distance between the bearing saddle and the axle will not decrease after contact, so the distance between the stator and the rotor is limited and will not collide.

[0055] Regarding the second aspect, during the overhaul of the axle, the carriage is separated from the bogie, and the bogie is separated from the axle. When separating the bearing saddle and the axle, the arc-shaped stator can be automatically separated from the rotor without additional disassembly of the generator, improving the efficiency of axle overhaul. The situation during reinstallation of the axle after overhaul is similar and will not be elaborated here.

[0056] Furthermore, it should be noted that the split structure and the separated installation cancel the generator bearing friction parts, simplify the structure, reduce the overall weight, decrease the acting force on the fixed installation position of the generator, lower the structural strength requirement for the generator fixed installation part, and improve the reliability. Further, the weight of the stator is applied to the bearing saddle, and the weight of the rotor is applied to the axle. The weight of the split generator is dispersed to the bearing saddle and the axle for bearing, dispersing the weight borne by each part, lowering the structural strength requirement for the generator fixed installation part, and improving the reliability. Also, since the friction parts such as the generator bearing are cancelled, bearing wear faults can be avoided, and the reliability of the generator itself structure is improved.

[0057] The following specifically describes the specific structure and power generation method of the generator in the embodiment of the present invention under the above split structure and separated installation method.

[0058] In some embodiments, the rotor is a rotor core with a gear-shaped radial cross-section. It should be noted that the radial cross-section is a cross-section perpendicular to the rotation axis of the rotor. After the motor is installed, the rotation axis of the rotor coincides with the rotation axis of the axle. Exemplarily, the gear-shaped rotor core includes a plurality of rotor teeth. For example, the number of teeth of the rotor is 9. Further, the shapes of the rotor teeth are the same, and the spacing between adjacent rotor teeth is the same.

[0059] In some embodiments, the stator includes i stator cores and i - 1 permanent magnets, where any permanent magnet is fixedly connected to two adjacent stator cores, and the radial cross-section shape of the stator core is a U-shaped groove; the U-shaped opening of any stator core faces the rotor;

[0060] Exemplarily, i is greater than or equal to 2. For example, i can be 2, that is, the stator includes at least two stator cores and one permanent magnet. Among them, the two stator cores clamp one permanent magnet. Another exemplarily, i can also be 3, that is, the first stator core and the second stator core clamp the first permanent magnet, and the second stator core and the third stator core clamp the second permanent magnet.

[0061] Exemplarily, the radial cross-sectional shape of the stator core is a U-shaped groove, and the U-shaped opening of the stator core faces the rotor. The U-shaped groove here can be a flat-bottom U-shaped groove or a U-shaped groove with a curvature. Exemplarily, the U-shaped groove stator core includes U-shaped groove teeth on both sides and a U-shaped groove opening in the middle. The following further describes the winding.

[0062] In some embodiments, a winding is correspondingly arranged for any permanent magnet, and the winding passes through the interiors of two adjacent U-shaped grooves and is arranged around the permanent magnet;

[0063] Exemplarily, the number of windings is the same as the number of permanent magnets. For example, one permanent magnet is provided with one winding.

[0064] Exemplarily, the winding surrounds the permanent magnet corresponding to the winding. From the radial cross-section, the winding wire passes out from the inside of the opening of a U-shaped groove, winds around the permanent magnet, and then passes into the opening of another adjacent U-shaped groove.

[0065] Exemplarily, the winding is a single-coil winding. A single-coil winding is a winding composed of a single coil. A single-coil winding is composed of a complete coil, and the coil is usually wound with an insulated wire (such as enameled wire) according to a predetermined winding rule. Exemplarily, the generator is a single-phase generator.

[0066] The following describes the pole direction of the permanent magnet and the magnetic path.

[0067] In some embodiments, the poles of the permanent magnet are parallel to the rotation direction of the axle; among them, the stator cores on both sides of the permanent magnet and two adjacent rotor teeth form a main magnetic path passing through the winding.

[0068] Exemplarily, the connecting line direction between the N pole and the S pole of the permanent magnet is the pole direction, and the N pole and the S pole respectively point to the opposite directions of a straight line. The rotation direction of the axle is a circle, and the direction of the pole can be tangent to the rotation direction of the axle.

[0069] It should be noted that the N pole of the permanent magnet points to one stator core, and the S pole points to one stator core. The magnetic resistance of the two cores is relatively small compared to air, and more magnetic flux of the permanent magnet passes through the stator core.

[0070] Further exemplarily, the stators on both sides of the permanent magnet and two adjacent rotor teeth form the main magnetic path passing through the winding. For example, the main magnetic path can be N pole → stator core → stator tooth → rotor tooth → rotor core → S pole. The following describes how the magnetic flux of the magnetic path changes and further realizes power generation through electromagnetic induction.

[0071] In some embodiments, when the axle drives the rotor to rotate, the generator is used to change the relative area between the rotor teeth and the stator U-shaped groove teeth, change the magnetic resistance of the magnetic path, cause the magnetic flux of the winding to change, form an induced electromotive force, and realize power generation.

[0072] In some embodiments, when the axle drives the rotor to rotate, the generator is used to make the rotor teeth and the stator U-shaped groove teeth have relative motion, the magnitude of the magnetic resistance of the magnetic path and the magnetic path change accordingly, so that the magnetic flux and the magnetic field direction passing through the stator winding change, and the stator winding generates an alternating induced electromotive force. When the external circuit of the winding is closed, an alternating induced current is generated to realize power generation.

[0073] It should be noted that when the gap between the rotor teeth and the stator teeth is small, the magnetic resistance is small and the magnetic flux between the rotor teeth and the stator teeth is large. In addition to the gap size, the relative area between the rotor teeth and the stator teeth (i.e., the stator U-shaped groove teeth) is also one of the influencing factors. The larger the relative area, the smaller the magnetic resistance between the rotor teeth and the stator teeth, and the larger the magnetic flux passing through the magnetic path. Thus, when the axle drives the rotor to rotate, the change in the relative area between the rotor teeth and the stator U-shaped groove teeth causes the change in the magnetic flux between the rotor teeth and the stator teeth, which also causes the change in the magnetic flux passing through the winding, forms an induced electromotive force in the winding, and realizes power generation.

[0074] The embodiment of the present invention provides a railway freight car axle-end generator and a power generation system. By setting the stator to be arc-shaped and installing it on the bolster or side frame above the axle end, and the rotor is gear-shaped circular, the rotor is installed on the axle end to form a split structure with the stator and the rotor separately installed. Further, by arranging the permanent magnet on the stator and fixing the two U-shaped iron cores of the stator to clamp the permanent magnet, when the gear-shaped rotor rotates with the axle, the rotor teeth and the stator U-shaped stator grooves and teeth have relative motion, the magnitude of the magnetic resistance of the magnetic path and the magnetic path change accordingly, so that the magnetic flux and the magnetic field direction passing through the stator winding change, and the stator winding generates an alternating induced electromotive force. When the external circuit of the winding is closed, an alternating induced current is generated to realize the power generation of the generator. The stator of the present invention is supported by the bolster or side frame, and the rotor is supported by the axle. The stator and the rotor are independent split structures. There are no friction parts such as bearings, the structure is simple, the structural strength requirement for the fixed installation part of the generator is reduced, the reliability is improved, and the maintenance cost is reduced.

[0075] The stator of the present invention is supported by a bearing saddle, and the rotor is supported by an axle. There is no need to additionally arrange a generator bearing support between the stator and the rotor, and the stator and the rotor are of a separable split structure. The generator bearing friction parts are cancelled, the structure is simplified, the overall weight is reduced, and the weight of the split generator is dispersed to the bearing saddle and the axle for bearing, reducing the structural strength requirements for the generator fixed installation part and improving the reliability. Also, since the generator bearing friction parts are cancelled, bearing wear faults are avoided, and the reliability of the structure of the generator itself is improved.

[0076] Moreover, when the axle of the vehicle bounces up and down during operation, the arc-shaped stator on the bearing saddle above the axle can be separated from the rotor, avoiding collision between the stator and the rotor and improving the reliability. When the axle is overhauled and the bearing saddle and the axle are separated, the arc-shaped stator can be automatically separated from the rotor without additional disassembly of the generator, improving the axle overhaul efficiency.

[0077] In a possible implementation manner, the number of teeth P of the rotor is determined based on the following formula:

[0078] P = 60 * f ÷ n

[0079] where f is the target power generation frequency of the generator, in hertz; and n is the rotational speed of the wheel set of the railway freight car at the target operating speed, in revolutions per minute.

[0080] Exemplarily, the target operating speed of the railway freight car can be the speed during normal operation.

[0081] In a possible implementation manner, the winding is a single-coil winding corresponding to each permanent magnet; multiple single-coil windings are connected in series or parallel according to the electromagnetic characteristics of the generator and the requirements of external electrical equipment.

[0082] Regarding the size relationship between the stator and the rotor, an embodiment is given below for illustration.

[0083] In a possible implementation manner, in the arc-shaped stator, the central angle of the permanent magnet, the central angle of the U-shaped slot teeth of the stator core, and the central angle of the U-shaped slot opening of the stator core are all the same as the central angle of the rotor teeth;

[0084] The central angle between two adjacent rotor teeth is the sum of the central angle of the arc-shaped stator core and the central angle of the permanent magnet; among them, when the relative area between any rotor tooth and any stator U-shaped slot tooth is the largest, the magnetic flux passing through the winding is the largest; when the relative area between any rotor tooth and any stator U-shaped slot opening is the largest, the magnetic flux passing through the winding is the smallest;

[0085] For any stator core, when the rotor teeth move from the first U-shaped slot tooth of the stator core to the second U-shaped slot tooth respectively, the magnetic field direction of the winding changes.

[0086] Exemplarily, along the rotation direction, the rotor teeth sequentially pass through the first U-shaped slot tooth of any stator core and move to the second U-shaped slot tooth.

[0087] It should be noted that the central angle of an arc refers to the angle formed by two radii and the arc they enclose in a circle. Each part of the arc-shaped stator is arc-shaped and has a certain central angle. For example, the central angle of the permanent magnet refers to the central angle of the arc-shaped permanent magnet.

[0088] Exemplarily, the central angle of the permanent magnet is the same as the central angle of the rotor teeth. Further exemplarily, the central angle of the U-shaped slot teeth of the stator core is the same as the central angle of the U-shaped slot opening of the stator core. Moreover, the central angle of the U-shaped slot teeth of the stator core is the same as the central angle of the rotor teeth, and the central angle of the U-shaped slot opening of the stator core is the same as the central angle of the rotor teeth. The above defines the relationship between each part of the stator and the rotor teeth. Next, the relationship between the distance between each part of the stator and the rotor teeth will be described.

[0089] Exemplarily, the central angle between two adjacent rotor teeth is the sum of the central angle of the arc-shaped stator core and the central angle of the permanent magnet. That is, the sum of the central angle of an arc-shaped stator core and the central angle of a permanent magnet is equal to the central angle between two adjacent rotor teeth. It should be noted that the central angle between two adjacent rotor teeth is the central angle of the arc from the center point of one rotor tooth to the center point of another adjacent rotor tooth.

[0090] It should be further noted that the above structural settings are for the purpose of: when the relative area between any rotor tooth and any stator U-shaped slot tooth is the largest, the magnetic flux of the winding is the largest; when the relative area between any rotor tooth and any stator U-shaped slot opening is the largest, the magnetic flux of the winding is the smallest; and, for any stator core, when the relative areas between the rotor tooth and the two U-shaped slot teeth of the stator core are the largest respectively, the magnetic flux directions passing through the winding are opposite. Thus, the magnetic flux of the winding continuously changes between the maximum and the minimum, and the direction of the magnetic field also changes, and a complete sine wave can be formed. The following will be described in detail with reference to the attached Figures 2 to 6 for a detailed description.

[0091] Figure 2 is the magnetic circuit schematic diagram of the first rotation position provided by the embodiment of the present invention; Figure 3 is the magnetic circuit schematic diagram of the second rotation position provided by the embodiment of the present invention; Figure 4 is the magnetic circuit schematic diagram of the third rotation position provided by the embodiment of the present invention; Figure 5 is the magnetic circuit schematic diagram of the fourth rotation position provided by the embodiment of the present invention;

[0092] Figure 6 is the magnetic circuit schematic diagram of the fifth rotation position provided by the embodiment of the present invention. Refer to Figures 2 to 6, are all schematic structural diagrams of radial cross-sections. Exemplarily, the rotor includes 9 rotor teeth. For example, it includes the first rotor tooth 11, the second rotor tooth 12, the third rotor tooth 13, the fourth rotor tooth 14, the fifth rotor tooth 15, the sixth rotor tooth 16, the seventh rotor tooth 17, the eighth rotor tooth 18, and the ninth rotor tooth 19. Exemplarily, there are 2 stator cores and 1 permanent magnet. Each stator slot tooth is successively the first stator tooth 21, the second stator tooth 22, the third stator tooth 23, and the fourth stator tooth 24. N and S represent the magnetic poles of the permanent magnet.

[0093] When the vehicle is moving, the rotor rotates synchronously with the wheelset. As the position of the rotor changes, the direction of the magnetic field passing through the winding will switch accordingly, and the magnetic flux will also change sinusoidally with the change of the magnetic reluctance of the magnetic circuit, thereby inducing a sinusoidal alternating current in the winding. That is, within a complete cycle of the rotor pole pitch, the magnetic circuit through which the magnetic flux passes always selects the path with the minimum magnetic reluctance to form a closed loop.

[0094] Starting from when any rotor tooth approaches the stator core, the magnetic flux passing through the winding first gradually increases from the minimum value to the maximum value, then gradually decreases to the minimum value, and then the direction of the magnetic field passing through the winding changes, and again makes the magnetic flux passing through the winding gradually increase from the minimum value to the maximum value, and then gradually decrease to the minimum value. The rotor teeth successively pass through two adjacent stator cores, completing 2 sine cycles. The change in the magnetic flux passing through the winding causes an induced electromotive force in the winding.

[0095] The following takes the first rotor tooth 11 as an example for illustration. Exemplarily, the rotor rotates in the clockwise direction; Exemplarily, the right side of the permanent magnet is the N pole and the left side is the S pole.

[0096] When the first rotor tooth 11 starts to rotate from Figure 2 the position shown, the magnetic circuit and the direction of the magnetic flux are: permanent magnet N pole → stator core → stator tooth 23 → ninth rotor tooth 19 → rotor core → first rotor tooth 11 → stator tooth 21 → stator core → permanent magnet S pole. At this time, the magnetic reluctance gradually decreases from the maximum, and the magnetic flux passing through the winding gradually increases from the minimum.

[0097] When the first rotor tooth 11 rotates to Figure 3 the position shown, the magnetic reluctance of the magnetic circuit becomes the minimum, and the magnetic flux passing through the winding reaches the maximum, and then starts to decrease.

[0098] When the first rotor tooth 11 rotates to Figure 4 the position shown, the magnetic reluctance of the magnetic circuit becomes the maximum. As the rotor continues to rotate, the magnetic flux passing through the winding will change direction, and the direction of the magnetic circuit and the magnetic flux becomes: permanent magnet N pole → stator core → stator tooth 24 → ninth rotor tooth 19 → rotor core → first rotor tooth 11 → stator tooth 22 → stator core → permanent magnet S pole. At this time, the magnetic reluctance of the magnetic circuit gradually decreases again as the rotor rotates, and the magnetic flux passing through the winding gradually increases again.

[0099] When the first rotor tooth 11 rotates to Figure 5 the position, the reluctance is minimized, the magnetic flux through the winding becomes maximum again, and since then the reluctance of the magnetic circuit will gradually increase, and the magnetic flux through the winding will gradually decrease.

[0100] When the first rotor tooth 11 rotates to Figure 6 the position shown, one cycle of the generator operation is completed. The next cycle will be completed by the second rotor tooth 12, the first rotor tooth 11, and the rotor core and the stator, and so on.

[0101] In the generator of this structure, the number of salient poles of the rotor is equivalent to the number of pole pairs of a general rotor-mounted permanent magnet generator type. The magnetic flux generated by the winding permanent magnet will follow Figures 3 to 6 the path shown in, and enter the corresponding rotor tooth pole through the stator tooth. When the rotor continuously moves between these two positions, the magnetic flux in the winding will periodically change between the positive and negative maximum values. Correspondingly, according to Faraday's law of electromagnetic induction, an alternating back electromotive force with continuously changing amplitude and phase will be generated at both ends of the winding.

[0102] In a possible implementation, it further includes a protective cover; the protective cover is fixedly connected to the stator together; the protective cover is arranged on the side of the stator and the rotor away from the shaft end; the projection of the protective cover towards the shaft end covers the stator and the rotor.

[0103] In the embodiment of the present invention, by providing a protective cover, it can effectively prevent dust, debris, metal chips, etc. from the outside from entering the gap between the stator and the rotor and other parts inside the motor. Further, fixedly connecting the protective cover to the bearing saddle can facilitate the disassembly and assembly of the axle.

[0104] In a possible implementation, it further includes a heat insulation protection layer; the heat insulation protection layer is arranged on the side of the stator close to the axle bearing.

[0105] It should be noted that in the generator of the embodiment of the present invention, the rotor rotates continuously, and each rotor takes turns to participate in power generation. However, the stator continuously undergoes magnetic flux changes, that is, when the motor is running, the permanent magnet in the stator will be in an alternating magnetic field, and its magnetic domains will continuously change orientation and flip. In this process, due to the friction and interaction between the magnetic domains, energy loss will occur, and this part of the loss is dissipated in the form of heat. The self-heating of the stator is large, which has a certain impact on the bearing.

[0106] The heat insulation protection layer in the embodiment of the present invention can significantly reduce the heat conduction from the stator to the bearing through thermal radiation, reduce the temperature rise of the bearing caused by absorbing the heat of the stator, help maintain the bearing within the normal working temperature range, and prevent the bearing temperature from rising too high.

[0107] In a possible implementation, an insulating layer is provided on the surfaces of the stator and the rotor. By providing the insulating layer in the embodiments of the present invention, short circuits between conductors with different potentials are effectively prevented, ensuring the normal operation of the motor or other electrical equipment. The insulating strength can also be increased, improving the voltage withstand performance of the equipment, enabling the equipment to withstand higher voltages, reducing the risk of electrical breakdown, and thus improving the electrical reliability of the entire equipment.

[0108] Exemplarily, a layer of epoxy resin glue can be coated on the stator and the rotor. By providing the epoxy resin glue in the embodiments of the present invention, moisture can also be blocked. The epoxy resin glue has good sealing and waterproof properties, and can form a moisture-proof barrier on the surfaces of the stator and the rotor, preventing external moisture and humidity from entering the interior of the equipment, avoiding problems such as a decrease in insulation performance and corrosion of components such as windings due to moisture, and extending the service life of the equipment. Preventing condensation: In some occasions with high environmental humidity or large temperature changes, condensation is likely to occur inside the equipment. Coating the epoxy resin glue can reduce the impact of condensation on the stator and the rotor, keeping the equipment dry and operating normally.

[0109] Figure 7 FIG. 7 is a schematic structural diagram of another axle-end generator of a railway freight car provided by the embodiments of the present invention; Figure 8 is provided by the embodiments of the present invention Figure 7 FIG. 11 is a schematic structural diagram of the A-A cross-section in FIG. 10. The A-A cross-section is a stepped cross-section. Exemplarily, the axle-end generator includes a generator stator, a stator bracket, a generator rotor, and a protective cover. Among them, windings and permanent magnets are installed on the generator stator; the generator stator is fixed on the stator bracket, the stator mounting seat is welded on the bearing saddle, and the stator bracket is fixed to the stator mounting seat by bolts; the rotor mounting seat is installed on the front cover by axle-end bolts, and the rotor is fixed to the rotor mounting seat by bolts; a protective cover is installed on the stator bracket to protect the generator. Compared with the embodiment of the present invention where the magnetic steel is installed on the rotor, the amount of magnetic steel used is small, the mass is small, the material cost is low, and maintenance is not required.

[0110] To eliminate the influence of the heat generated during the operation of the generator on the temperature rise of the bearing due to heat radiation, heat-insulating materials are added to the side of the protective cover near the bearing near the stator, so that the outer surface temperature of the protective cover near the bearing is relatively low, eliminating the influence of the generator heat generation on the bearing temperature.

[0111] Exemplarily, the inner and outer diameters of the rotor and the stator can be determined according to the structures of the front cover of the bearing of the bogie with different axle loads and the bearing saddle. Exemplarily, the radial thickness of the rotor and the stator and the size of the permanent magnet can be determined by the designed output power of the generator.

[0112] In a second aspect, the embodiments of the present invention provide a railway freight car axle-end power generation system, including the railway freight car axle-end generator in any of the above possible implementations.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A railway freight car shaft end generator, characterized in that: include: Rotor and stator; The rotor and stator are independently installed and fixed; the rotor is used to be installed on the end of the axle of a railway freight car and rotate with the axle; the stator is an arc with a central angle less than 180 degrees, and is used to surround the rotor and be fixed on a bearing saddle or side frame above the end of the axle; The rotor is a rotor core having a gear-shaped radial cross section; The stator comprises i stator cores and i-1 permanent magnets, wherein any permanent magnet is fixedly connected to two adjacent stator cores, and the radial cross-section of the stator core is a U-shaped groove; the U-shaped opening of any stator core faces the rotor; A winding is provided corresponding to each permanent magnet, and the winding passes through two adjacent U-shaped slots and is arranged around the permanent magnet; the magnetic poles of the permanent magnet are parallel to the rotation direction of the axle; wherein the stator cores on both sides of the permanent magnet and two adjacent rotor teeth form a main magnetic circuit passing through the winding; The generator is used to make the rotor teeth and the stator U-shaped slot teeth move relative to each other when the axle drives the rotor to rotate, and the magnetic resistance size and the magnetic circuit change accordingly, so that the magnetic flux and the direction of the magnetic field passing through the stator winding change, and the stator winding generates an alternating induced potential. When the external circuit of the winding is closed, an alternating induced current is generated to achieve power generation.

2. The railway freight car shaft end generator according to claim 1, characterized in that: In the arc-shaped stator, the center angle of the permanent magnet, the center angle of the stator core U-shaped slot teeth and the center angle of the stator core U-shaped slot opening are all the same as the center angle of the rotor teeth; The center angle between two adjacent rotor teeth is the sum of the center angle of the arc-shaped stator core and the center angle of the permanent magnet; when the relative area between any rotor tooth and any stator U-shaped slot tooth is the largest, the magnetic flux passing through the winding is the largest; when the relative area between any rotor tooth and any stator U-shaped slot opening is the largest, the magnetic flux passing through the winding is the smallest; For any stator core, when the rotor teeth move from the first U-shaped slot tooth to the second U-shaped slot tooth of the stator core, the direction of the magnetic field passing through the winding changes.

3. The railway freight car shaft end generator according to claim 1, characterized in that: The stator at least includes two stator cores and a permanent magnet.

4. The railway freight car shaft end generator according to claim 1, characterized in that: The number of teeth P of the rotor is determined based on the following formula: P=60*f÷n Wherein, f is the target power generation frequency of the generator, in Hertz; n is the wheelset speed of the railway freight car at the target operating speed, in revolutions per minute.

5. The railway freight car shaft end generator according to claim 1, characterized in that: The windings are such that each permanent magnet corresponds to a single coil winding; multiple single coil windings are connected in series or in parallel according to the electromagnetic characteristics of the generator and the needs of external electrical equipment.

6. The railway freight car shaft end generator according to claim 1, characterized in that: Also includes protective covers; The protective cover is fixedly connected to the stator; The protective cover is arranged on a side of the stator and the rotor away from the shaft end; the projection of the protective cover to the shaft end covers the stator and the rotor.

7. The railway freight car shaft end generator according to claim 1, characterized in that: The installation gap between the stator and the rotor is determined based on the installation tolerance of the rotor and the stator and the generator air gap design requirements.

8. The railway freight car shaft end generator according to claim 1, characterized in that: It also includes a thermal insulation protective layer; The heat insulation protection layer is arranged on a side of the stator close to the axle bearing.

9. The railway freight car shaft end generator according to claim 1, characterized in that: Insulation layers are provided on surfaces of the stator and the rotor.

10. A railway freight car axle end power generation system, characterized in that: The invention comprises the railway freight car shaft end generator as claimed in any one of claims 1 to 9.

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