Drive system for motorised bogies and freight locomotive provided with said system

Abstract

The present invention relates to a drive system for motorised bogies of railway vehicles, wherein for the transmission of movement to the wheels (6) of the bogie, the system comprises a motor (1) that is arranged parallel to at least one wheel (6) axle (4) with a reducer (2) coupled to said axle (4) by means of a suspension tube (5). The suspension tube comprises a removable mechanical coupling (3) for direct attachment between the motor (1) assembly and the reducer (2) assembly, the input shaft (2.3) of the reducer (2) being supported on two bearings (2.1, 2.2) located on either side of the pinion of the input shaft (2.3) and the reducer being a dual-stage reducer.

Description

[0001] DESCRIPTION

[0002] TRACTION SYSTEM FOR MOTORIZED BOGIES AND FREIGHT LOCOMOTIVE PROVIDED WITH SAID SYSTEM

[0003] Technical sector

[0004] The bogie is the frame that supports a set of wheelsets on a railway vehicle. It is a set of two (or sometimes three or more, depending on the model) pairs of wheels, mounted on two axles close together and parallel to each other. It is the rolling structure on which the wagons, rail cars, and locomotives designed to run on rails rest.

[0005] Bogies are classified, among other things, based on their application and whether or not they are motorized. Based on their application, they are classified as freight or passenger bogies, and based on their motorization, they are classified as motorized bogies or trailer bogies.

[0006] Well, the object of the present invention is a traction system for the motorized bogies of a freight locomotive and more specifically for a freight locomotive with at least two bogies, each of them with at least two axles, and more preferably at least three axles (six axles in total per locomotive).

[0007] The locomotive provided with this traction system is also the object of this invention.

[0008] State of the art

[0009] In this specific application of motorized bogies for locomotives not specifically dedicated to freight transport, different traction systems are known.

[0010] For example, the use of motors arranged parallel to the drive axle of the bogie wheels is well known, in which the motor rotor rests on two bearings and in turn the pinion gear of the reducer is mounted directly on the end of the motor rotor, leaving the pinion cantilevered. The problem that arises, especially in the case of freight locomotives, is the breakage of the pinion on the input shaft to the reducer, which rotates integrally with the motor shaft, normally due to the high forces to be supported, a cause that is exacerbated by the need to be able to count on increasingly greater torsional torques so that the locomotives are capable of transporting an increasingly greater load. Given the common block structure of the motor and the reducer forming an overall unit, the breakage of the pinion implies the replacement of the entire assembly, with the inconveniences and costs that this entails.

[0011] Swiss patent CH630303 describes a traction system in which the motor is mounted on the axle of a bogie, with a gearbox in which the pinion on the input shaft of the gearbox, which rotates integrally with the motor shaft, rests on two bearings. The motor is fixed to the bogie frame, with an articulated transmission between the motor and gearbox shafts, allowing a certain degree of freedom to compensate for misalignment or vibrations. This mounting, supported by two bearings, makes the pinion more robust, but is not sufficient for a freight locomotive.

[0012] Patent GB945473 A discloses the use of what is known in the railway sector as a "cannon-box." This is a motorization concept in which the motor and gearbox assembly are coupled to the wheel axle via a tube known as a "suspension tube." This suspension tube surrounds the axle and is supported by two bearings, allowing the motor and gearbox to be securely attached to the wheel axle and always ensuring alignment between the connecting bearings and the wheel axle.

[0013] In view of the known state of the art, various solutions are used to position the motor parallel to the axis of a motorized bogie, but always in a combined motor-reducer block. This does not address the aforementioned motor failure due to its inability to withstand the torque. All of this is applied to a single bogie of a motorized railway vehicle.

[0014] Object of the invention

[0015] In order to meet this objective and solve the technical problems discussed so far, in addition to providing additional advantages that may be derived later, the present invention provides a motorized bogie traction system for railway vehicles, which for the transmission of movement to the bogie wheels comprises a motor arranged parallel to at least one wheel axle with a reducer coupled to said axle by means of a suspension tube, which comprises a removable mechanical coupling with direct connection between the motor assembly and the reducer assembly, and the input shaft of the reducer being bi-supported on two bearings located on each side of the pinion of the input shaft, and the reducer comprising a double-stage transmission distribution.

[0016] This configuration solves the problems that caused pinion breakage. By having the reducer input shaft on a double support, with a bearing on each side of the reducer input shaft pinion, the pinion's resistance to high torque is improved, thus improving the reliability of the rotor-pinion assembly. Furthermore, the reducer's double stage allows for an increased reduction ratio, thereby reducing the torque on the input pinion. Together with the double bearing, they prevent the pinion from breaking, providing a more robust solution for high torque applications.

[0017] Additionally, the double stage, in addition to improving performance under high torques, allows the engine to rotate at higher revolutions, improving the efficiency of the present invention and therefore resulting in lower consumption, especially at low operating speeds of the locomotive.

[0018] Furthermore, the traction system object of the invention comprises a direct coupling between the motor shaft and the reducer shaft, which in this solution is a block independent of the motor, such that the mechanical coupling provides a detachable coupling between the motor and reducer, which facilitates maintenance or replacement tasks in case of breakage, without having to disassemble the entire motor-reducer assembly as in the prior art; simply by removing the coupling's screwing means, the motor and reducer can be uncoupled. Another advantage of the existence of said detachable coupling is that it also allows the torque transmission between the traction motor and the axle to be decoupled, such that the drive axle can be operated as if it were a trailer axle. This can be useful for continuing to operate the locomotive despite a motor failure.

[0019] The combination of the aforementioned features together provides a more robust and compact solution for supporting high torques, such as those required in freight locomotive applications. This prevents the gearbox pinion from breaking under high torque and provides a solution that is easy to maintain and assemble. Preferably, the mechanical coupling between the motor and gearbox comprises two halves joined by teeth for torque transmission and screws for the detachable fastening of the coupling between the motor and gearbox. This configuration allows for the absorption of offset or misalignment by establishing a direct coupling of the motor to the gearbox, which is detachable and allows the motor to be separated from the gearbox, all while maintaining power transmission.

[0020] According to another feature of the invention, the motor is in turn fixed to the suspension tube by mechanical means, preferably by bolting. This achieves a fixed motor-to-axle arrangement, resulting in a very compact assembly that keeps the motor parallel to the wheel axle. Thus, the motor being an independent element, it is connected to the reducer on the axle side and fixed to the suspension tube, as well as to the bogie frame through an intermediate mechanism such as a reaction rod that facilitates its mobility when the bogie's suspensions move. This ensures that the motor remains parallel to the wheel axle at all times, allowing the assembly to move in a cohesive manner, achieving a more robust and compact transmission system.

[0021] The present invention also contemplates a freight locomotive comprising at least two bogies with at least two axles each, and more preferably a locomotive with three axles each, these being the most common on the market, and preferably at least two of the axles being motorized.

[0022] Preferably, the locomotive comprises independent traction control means for each axle motor, with an inverter for each motor of the corresponding driven axle. This arrangement allows for independent control of each rotation of the different axles in a mechanical-electronic format. It should be noted that in the specific application of motorized bogies to a freight locomotive, the application limit is not torque or power, but rather the adhesion of the wheels to the track. There may be excess power available, but the torque may have to be reduced at a given moment because the adhesion limit of a wheel is reached. Therefore, in known solutions to avoid this, if at least one of the axles slips, the torque is reduced for all the locomotive axles. However, with the independent axis control of the invention, the adhesion limit situation is detected and the torque is reduced for only the corresponding axle.That is, each motorized axle of a pair of wheels has its own motor and inverter. Description of the figures.

[0023] Figure 1 shows an exploded schematic view of the traction system object of the invention for a wheel axle.

[0024] Figure 2 shows a perspective view of the assembly of Figure 1 in the assembly position.

[0025] Figure 3 shows a detailed perspective view of the coupling between the motor and the reducer.

[0026] Figure 4 shows a sectional view of the assembled assembly showing the details of the coupling.

[0027] Figure 5 shows a detailed sectional view showing a double-stage reducer.

[0028] Figure 6 shows a schematic top view of a freight locomotive with two bogies with three driven axles each.

[0029] Detailed description of the invention

[0030] In view of the aforementioned figures, and in accordance with the numbering adopted, one can observe in them a preferred non-limiting embodiment of the invention, which comprises the parts and elements indicated and described in detail below.

[0031] The motorized bogie traction system for railway vehicles of the invention comprises a system coupled to at least one wheel axle of a bogie. Figure 1 shows that said traction system consists of a motor assembly (1) coupled to a reducer (2) arranged as an assembly independent of the motor (1), and both assemblies coupled by means of a mechanical coupling (3) that allows mechanical transmission while allowing the independent disassembly of both assemblies.

[0032] As can also be seen in figure 2, the reducer (2) is fixed to the axle (4) of wheels (6) by means of an element known as suspension tube (5), such that the reducer (2) is fixed to the axle (4) forming a block together with said suspension tube (5), and therefore providing a fixing of the motor (1) to the axle (4) through the fixing of the reducer (2) to which it is coupled. This arrangement keeps the motor (1) parallel to the axle (4) forming a motorized axle (4) that provides a compact and easy-to-maintain solution.

[0033] The aforementioned mechanical coupling (3) preferably comprises a toothed coupling between the parts (figure 3), the coupling being formed by two articulated halves, which allow angular and axial movements to absorb offset or misalignment. Furthermore, as can be seen in figure 4, the aforementioned toothing (3.1) together with the screwed fixing by means of the fixing screws (3.2) gives the assembly, motor (1) reducer (2), the quality of being removable, allowing the motor (1) to be separated independently from the reducer (2) for maintenance or replacement work, all while maintaining the correct power transmission.

[0034] In figure 4 you can also see the two-supported arrangement of the input shaft (2.3) of the reducer (2) with a bearing (2.1) on one side and a bearing (2.2) on the other side of the input pinion. This arrangement allows the reaction forces on the input shaft (2.3) of the reducer to be supported in the most effective way to minimize misalignments of the meshing point of the input pinion with the other toothed wheel in high torque situations, solving the main problem detected in freight locomotives mainly in the field of high performance applications in diesel-electric freight locomotives.

[0035] In these applications, the motor forms a single assembly with the reducer, the wheel axle has a crown that meshes with a pinion attached to the motor shaft and supported only by a bearing on one side, as a result of which at low speeds and high torques said support bearing is not able to sufficiently compensate the reaction forces on the pinion, making the misalignment in the interdental contact excessive for the loads to be transmitted, sometimes causing the pinion to break.

[0036] As shown in figure 5, the reducer (2) is double stage, which allows to increase the reduction ratio of the reducer, making the motor work with lower torque levels and higher speeds, improving its efficiency. The reduction in torque and the improvement in efficiency influences the sizing of the motor (1) making it possible to use smaller motors, resulting in a more economical and more compact solution. In said figure 5 you can also see in a better way the fixing between the motor (1) and the suspension tube (5), which is produced by means of fixing bolts (5.1), which provide a more stable fixing of the motor (1).

[0037] The preferred application of this traction system is directed to freight locomotives and preferably to a freight locomotive (7) as can be seen schematically in figure 6, the invention contemplating a freight locomotive (7) preferably with a traction system on each of the axles (4) of wheels (6) of the locomotive (7). The locomotive (7) preferably comprising two bogies (8) with three axles (4) each motorized with the traction system object of the invention.

[0038] According to a practical embodiment, each motorized axle (4) of the locomotive (7) comprises independent traction control means for each motor (1) with a corresponding inverter for each motor (1). This provides independent control of each rotation of the different axles (4) in a mechanical-electronic format. With this configuration, it is possible to reduce the torque of an axle (4) individually, for example, when it is detected that it has exceeded the adhesion limit, without it being necessary to lower the torque of all the axles (4) of the locomotive.

Claims

CLAIMS 1.- Motorized bogie traction system for railway vehicles, which for the transmission of movement to the wheels (6) of the bogie comprises at least one motor (1) arranged parallel to at least one axle (4) of wheels (6) with a reducer (2) coupled to said axle (4) by means of a suspension tube (5), characterized in that it comprises a removable mechanical coupling (3) of direct connection between the motor assembly (1) and the reducer assembly (2), and the input shaft (2.3) of the reducer (2) being bi-supported on two bearings (2.1, 2.2) located on each side of the pinion of the input shaft (2.3), and because the reducer (2) comprises a double-stage transmission distribution. 2.- Motorized bogie traction system according to the previous claim, where the articulated mechanical coupling (3) comprises two halves fixed in a removable manner by means of teeth, for the transmission of torque between the motor shaft (1) and the reducer shaft (2). 3.- Motorized bogie traction system according to claim 1 or 2, where the motor (1) is fixed to the suspension tube (5) by mechanical means. 4.- Freight locomotive (7) comprising at least two bogies (8), each of them with at least two axles, at least two of the axles being motorized axles with a traction system according to any one of the preceding claims. 5.- Freight locomotive (7) according to the preceding claim, comprising independent traction control means for each motor (1) with an inverter for each motor (1) of the corresponding motorized axle (4).

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