Air outlet hood for a self-ventilated traction motor for a vehicle

Abstract

The invention relates to an airflow hood (9) for a self-ventilated traction motor (6,7), mechanically attached to the casing of the self-ventilated traction motor (6,7) and substantially surrounding the rotatable motor shaft of said traction motor (6,7), said airflow hood (9) comprising a body mounted on said casing and an air duct presenting an airflow inlet at one end and an airflow outlet (15) directed downwards at the other end. The airflow hood (9) is arranged at the proximal end of the traction motor (6,7) opposite the shaft extending said rotatable motor shaft for driving the axles (3,4), the airflow outlet (15) being arranged asymmetrically on one side of said traction motor (6,7) with respect to the longitudinal axis of said traction motor (6,7).

Description

[Technical field]

[0001] The present invention relates generally to the technical field of electric vehicles powered by one or more electric traction motors.

[0002] More specifically, the present invention relates to cooling vehicle traction motors to mitigate high temperatures in the drive shaft area. [Background technology]

[0003] In the following, longitudinal and transverse are to be understood as axes parallel and perpendicular to the normal direction of movement of the vehicle in question. The same applies to the front and rear as well as the top and bottom, which correspond to the normal positions of the rail vehicle.

[0004] Typically, a rail vehicle comprises a car body mechanically connected to at least two bogies, which are frames on which at least one pair of axles are mounted, with braking equipment and a suspension assembly connecting the axles to the frame. In the case of towed or self-propelled rail vehicles, at least one axle of the bogie is driven by an electric traction motor.

[0005] In operation, the traction motor is air-cooled. Self-ventilated traction motors are known in which a fan is attached to the free end of the rotatable motor shaft of the traction motor, the other end of which is connected to the drive axle, for example by a gearbox. When the rotatable motor shaft of the traction motor drives the axle, the fan also rotates and generates an axial air flow that moves along the casing and the rotatable motor shaft, thereby discharging heat generated inside the traction motor to the outside. Typically, such traction motors are provided with an air flow hood at the end of the traction motor opposite the fan in order to guide the exhaust of the air flow downwards.

[0006] The area of ​​the bogie where the airflow hood is located contains several significant mechanical complexities as mentioned above that significantly limit the space available for the installation of the airflow hood. Additionally, hot areas can be created by the heat being dumped to the outside to cool the traction motors.

[0007] In the prior art, the airflow hood presents airflow outlets that are directed downwards and are arranged symmetrically on both sides of the longitudinal axis of the traction motor. The downward orientation of the airflow outlets leads the hot air discharged from the airflow hood to the track bed. This design of the airflow hood mainly results from the spatial constraints in this area of ​​the bogie and aims to avoid heating the underframe of the railcar. However, this does not prevent the hot airflow from heating the mechanical complex adjacent to the traction motor.

[0008] Chinese Utility Model No. 208337341 discloses an airflow hood for a self-ventilated traction motor, which is mechanically mountable on a casing of the traction motor. The airflow hood comprises a body mountable on the casing and substantially surrounding a longitudinal axis of the traction motor. Furthermore, the airflow hood comprises an air duct presenting an airflow inlet at one end and an airflow outlet at the other end.

[0009] There is therefore a need for efficient cooling of the traction motor without contributing to the heating of the mechanical complexes surrounding the traction motor, such as the brake equipment or gearbox, despite the high density of mechanical complexes in this area of ​​the bogie.

[0010] Furthermore, self-ventilated traction motors are sensitive to high local ambient temperatures. For example, if two traction motors are arranged on one bogie, the upstream traction motor, which is located in front of the downstream traction motor with respect to the airflow that occurs under the railcar when traveling, can generate a so-called recirculation effect. This means that hot air from the upstream traction motor is drawn into the downstream traction motor. This recirculation effect is accentuated by the common arrangement of the traction motors' airflow hoods, where the air intake of the downstream traction motor is aligned to a certain extent with the air outlet of the upstream traction motor. This can lead to overheating of the traction motors and a shortened service life.

[0011] Typically, air inlets and outlets are at either end of the traction motor and the cooling airflow is driven by an internal fan mounted on the rotatable motor shaft. Time-averaged losses during the traction motor duty cycle can be as much as 10 kW, significantly heating the cooling air. There is a need to maximize cooling performance and reduce the noise generated by the cooling airflow without substantial over-temperatures in the areas of the bogie's critical mechanical complex located downstream of the traction motor. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] China Utility Model No. 208337341 Summary of the Invention [Problem to be solved by the invention]

[0013] The object of the present invention is to remedy all or at least some of the above mentioned technical problems, such as by preventing or mitigating hot air from an upstream traction motor from reaching and being entrained in a downstream traction motor, for example mounted on the same bogie or a downstream bogie, and further by preventing the impact of the hot air on the vehicle underframe or other composites mounted on the bogie. [Means for solving the problem]

[0014] To this end, according to a first aspect of the invention, an airflow hood for a self-ventilated traction motor is proposed which can be mechanically attached to a casing of the self-ventilated traction motor, said airflow hood comprising a body mountable on said casing and substantially surrounding the longitudinal axis of said traction motor, and an air duct presenting an airflow inlet at one end and an airflow outlet directed downwards at the other end, said airflow hood being located at a proximal axial end of the casing opposite to a distal axial end of the casing at which a fan is mounted and from which a rotatable motor shaft projects axially to drive an axle.

[0015] In a preferred embodiment of the invention, the airflow outlets are arranged asymmetrically with respect to a vertical axial plane containing the longitudinal axis of the traction motor.

[0016] According to one embodiment of the invention, the airflow enters the body substantially axially and exits by an airflow outlet substantially tangential to a cylinder coaxial with said traction motor and / or the airflow outlet is positioned substantially horizontally facing downwards.

[0017] According to another embodiment of the invention, an airflow outlet is arranged on a side of the traction motor facing away from an axle driven by the traction motor.

[0018] According to a further embodiment of the invention, the cross section of the air duct increases progressively towards the airflow outlet and / or the airflow outlet extends over substantially all of the underside of the body of the airflow hood.

[0019] According to another embodiment of the invention, the air duct extends substantially along a side of said body opposite said axle.

[0020] Alternatively, the airflow outlet is located on a side of the axle opposite the traction motor and / or the airflow outlet is arranged substantially horizontally.

[0021] According to one embodiment of the invention, the air duct extends past said body to pass to the other side of the axle and / or the cross section of said air duct gradually decreases towards the airflow outlet.

[0022] According to another embodiment of the invention, the airflow hood is substantially U-shaped, the body forms a first leg of the U-shaped airflow hood, the air duct forms a second leg of the U-shaped airflow hood, and the axle driven by the traction motor is disposed between the first and second legs of the U-shaped airflow hood.

[0023] According to a second aspect of the invention, a self-ventilated traction motor is proposed, comprising a casing surrounding a rotatable motor shaft extended by a shaft for transmitting a driving force, and a fan attached to the rotatable motor shaft at the shaft side for generating a cooling airflow circulating longitudinally through the self-ventilated traction motor. The self-ventilated traction motor further comprises the above-mentioned airflow hood for guiding the cooling airflow exhaust.

[0024] According to a third aspect of the invention, a railway bogie is proposed comprising a frame, at least one axle rotatably mounted on said frame and at least one gearbox mechanically connected to said at least one axle, the railway bogie further comprising at least one self-ventilated traction motor as defined above for driving said at least one gearbox.

[0025] According to another embodiment of the present invention, a railway bogie includes two gearboxes, two axles, and an upstream self-ventilated traction motor and a downstream self-ventilated traction motor, each connected to a corresponding gearbox for driving a respective axle.

[0026] Other features and advantages of the present invention will become apparent from the following description of embodiments of the invention, which are provided as non-limiting examples for achieving various aspects of the invention. [Brief description of the drawings]

[0027] The description refers to the accompanying figures, which also illustrate, by way of example, various embodiments of the invention.

[0028] [Figure 1] 1 shows a perspective view from below right of the rail car. [Diagram 2] 1 shows a longitudinal section of a traction motor; [Diagram 3] 1 shows a perspective view from below of a self-ventilated traction motor according to a first embodiment of the invention; [Figure 4] FIG. 2 shows a side view of an upside down airflow hood. [Diagram 5] FIG. 2 shows a perspective view from below of a self-ventilated traction motor with an airflow hood according to a second embodiment of the invention. [Figure 6] FIG. 6 shows a side view of the airflow hood of FIG. 5 in an upside-down position.

[0029] Identical or similar features are designated with the same reference numerals in all figures for the convenience of the reader. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Figure 1 shows a bogie 1 for a vehicle, presenting a frame 2 on which two axles are rotatably mounted, namely an upstream axle 3 at the front of the bogie 1 and a downstream axle 4 at the rear of the bogie 1. Upstream and downstream should be understood with respect to the airflow relative to the vehicle moving underneath it when traveling in direction 5. An upstream traction motor 6 and a downstream traction motor 7 drive and rotate the upstream axle 3 and the downstream axle 4, respectively, via a gearbox 8. The upstream and downstream traction motors 6 and 7 are self-ventilated electric motors.

[0031] As shown in Figure 2, these traction motors 6 and 7 are so-called semi-open motors, which are more effective than closed types in terms of cooling the ends of the traction motors. For convenience, in the following, instead of the upstream and downstream traction motors 6 and 7, reference will be made only to the traction motor 6.

[0032] The power delivered by the traction motor 6 depends on the performance of the cooling of the traction motor, which is achieved by a cooling airflow 20 generated by a fan 19. The fan 19 is driven by a rotatable motor shaft 18 of the traction motor 6. The fan 19 is mechanically attached to the end of the rotatable motor shaft 18, which is connected to the gearbox 8. When the traction motor 6 rotates, the fan 19 takes in fresh air and pushes it axially through the interior of the traction motor 6, in particular to cool the coil windings 22 attached to the casing 12 around the rotatable motor shaft 18 and the magnets 23 attached to the rotatable motor shaft 18 opposite the coil windings 22. After discharging the heat of the traction motor 6, the cooling airflow 20 leaves the traction motor 6 by the end opposite the gearbox 8, where it is collected by the airflow hood 9.

[0033] The self-ventilated traction motor 6 is part of an assembly used in rail vehicles and comprises a casing 12 and a motor shaft 18 rotatable about a horizontal longitudinal axis 17 of the self-ventilated traction motor 6. A fan 19 is driven by the rotatable motor shaft 18 to blow cooling air into the casing 12. The fan 19 is arranged at the distal axial end 10 of the casing 12, and an airflow hood 9 surrounds the longitudinal axis 17 at the proximal end 11 of the casing 12 to collect said cooling airflow 20 from the casing 12. The airflow hood 9 comprises an air duct 16 presenting a downward outlet 15 for directing the collected cooling airflow 20 downward to the outside. The rotatable motor shaft 18 protrudes from the distal end 10 of the casing 12 to drive one or more axles 3 or 4 of the rail vehicle, and the airflow outlet 15 is asymmetrical with respect to a vertical axial plane including the longitudinal axis 17.

[0034] By arranging the fan 19 at the distal end 10 of the traction motor 6 and the airflow hood 9 at the proximal end 11, the problem of leakage of hot air along the rotatable motor shaft 18 is significantly reduced, since the latter does not have to pass through the airflow hood 9. This arrangement according to the invention therefore contributes to avoiding circulation of hot air between the complexes located in the traction motor area. This is reinforced by the fact that the air duct 16 and the airflow outlet 15 effectively guide the exhaust of the hot air downwards, away from the traction motor 6, where it is moderated by the flow of cool air below the bogie 1.

[0035] The airflow hoods 9 attached to the traction motors 6 direct the hot air escaping from the traction motors 6 towards the ground below the frame 2 of the bogie, where the air current moving under the vehicle is strongest. This allows the hot air discharged downwards by the airflow hoods 9 to mix more effectively with the air current, causing a significant reduction in the air temperature. This improves the cooling performance of the traction motors 6. In particular, the air discharged by the airflow hoods 9 of the upstream traction motors 6 and sucked in by the fan of the downstream traction motors 7 is cooler and so-called air recirculation has less effect on the cooling of the downstream motors 7.

[0036] The details of the airflow hood 9 attached to the traction motor 6 are shown in Figs. 2 and 3. At the distal end 10 of the traction motor 6 on the side of the gearbox 8, the rotatable motor shaft is connected to a corresponding gearbox 8 (not shown), and at the proximal end 11 opposite the gearbox 8, the airflow hood 9 is mechanically attached, preferably in a removable manner, to the casing 12 of the traction motor 6. A pressurized cooling airflow 20 circulates longitudinally inside the casing 12 throughout the entirety of the casing 12 in order to efficiently and uniformly cool the traction motor 6. The heated cooling airflow 20 then axially leaves the casing 12 from the proximal end 11 of the traction motor 6, surrounds the rotatable motor shaft, passes through the part of the airflow hood 9 surrounding the rotatable motor shaft and adjacent to the casing 12, and is collected in the body 13. The hot airflow is then transferred to the air duct 16 through an airflow inlet 14 arranged at the connection between the body 13 and the air duct 16. The body 13 encases the proximal end 11 of the traction motor 6 so as to pass the pressurized hot air through the airflow hood 9. The hot air collected in the body 13 then exits the airflow hood 9 through the airflow outlet 15. The airflow outlet 15 is located at a first end of the air duct 16 opposite the airflow inlet 14. The airflow outlet 15 is disposed substantially horizontally and faces downwards so that the pressurized hot air after being transferred from the body 13 of the airflow hood 9 into the air duct 16 is blown out of the airflow hood 9 downwards toward the track bed by the airflow outlet 15 of the air duct 16.

[0037] The airflow outlets 15 are arranged asymmetrically with respect to a vertical axial plane containing the longitudinal axis 17 of the traction motor 6. This arrangement allows the airflow hood 9 to optimally use the limited space available in this area of ​​the bogie 1, so that the design of the airflow hood 9, and in particular the air ducts 16, can effectively guide the heated cooling airflow 20 towards the track bed and away from the heat-sensitive composites surrounding the traction motor 6. Furthermore, the heated cooling airflow 20 is effectively guided towards the high-speed airflow moving under the bogie, where it effectively mixes with the cooler air and is unlikely to contribute to overheating of the downstream traction motor in case of air recirculation. This asymmetric arrangement ensures that only one flow of hot air blows out of the airflow hood 9, thereby avoiding aerodynamic turbulences generated by other airflows escaping from the airflow hood.

[0038] The outgoing hot airflow leaves the traction motor 6 substantially axially, is directed substantially radially in the body 13 and then takes up a tangential direction in the air duct 16 to a cylinder coaxial with the traction motor 6. This tangential escape direction as the hot airflow leaves the airflow hood 9 by the airflow outlet 15 contributes to an effective moderation of the hot airflow by the flow of cool air. The length of the air duct 16 effectively changes the direction of the hot airflow and helps to limit the turbulence of the hot airflow. The longer the air duct 16, the closer the air is discharged to the ground. The airflow relative to the vehicle gradually increases towards the ground and therefore the mixing of the hot air into the cooler airflow becomes more effective from the point of view of cooling. The air duct 16 therefore extends away from the body 13 above the upstream axle 3 (or the downstream axle 4, depending on whether the upstream traction motor 6 or the downstream traction motor 7 is considered). The air duct 16 then extends further downwards on the side of the upstream axle 4 opposite the upstream traction motor 6. This arrangement allows the air duct 16 to have a sufficient length to effectively direct the hot airflow and limit turbulence at the airflow outlet 15.

[0039] For this purpose, the airflow hood 9 is substantially U-shaped. The body 13 attached to the casing 12 forms a first leg of the U-shaped airflow hood 9. The air duct 16 forms a second leg of the U-shaped airflow hood 9, located to the side of the axle 3. With this arrangement, the axle 3 is located between the first and second legs of the U-shaped airflow hood 9, which allows the air duct 16 to make effective use of the available space in order to maximize its length.

[0040] In order to accelerate the hot air flow in the air duct 16, the cross section of the air duct 16 decreases from the body 13 to the airflow outlet 15. The speed of the hot air flow leaving the airflow outlet 15 also contributes to its effective injection in the cold air flow between the bogie 1 and the rail.

[0041] Figures 4 and 5 show an airflow hood 9 mounted on a traction motor 6 according to a second embodiment of the invention. In this embodiment of the airflow hood 9, the airflow outlets 15 are arranged on the side of the longitudinal axis 17 of the traction motor 6 opposite the axle 3 driven by the traction motor 6. This arrangement of the airflow outlets avoids that the hot air leaving the airflow hood 9 heats up the axle 3 on the side of the traction motor 6 and the bearings of the axle 3 (not shown).

[0042] The airflow outlet 15 is arranged horizontally, flush with the underside of the body 13 of the airflow hood 9, and faces downwards as described above. The air duct 16 runs along the side of the body 13 from the upper side of the body 13 to the airflow outlet 15 on the underside of the body 13. This design of the air duct 16 allows a more compact design of the airflow hood 9 to be achieved, while still being able to sufficiently guide the hot airflow downwards to the rails.

[0043] As shown in Fig. 4, mainly for cheaper manufacturing of the airflow hood 9, there is no separation wall between the air duct 16 and the body 13. Alternatively, a separation wall may be arranged between the body 13 and the air duct 16. The cross section of the air duct increases from the connection with the body 13 and the airflow outlet 15. According to a further design option of the airflow hood 9, the airflow outlet 15 extends past the air duct 16 on substantially the entire underside of the body 13. These features contribute to reducing the airflow impedance of the entire air duct in order to seamlessly escape the hot airflow downwards towards the ground.

[0044] The above description and drawings relate to various embodiments of certain aspects of the invention, in particular the design of air ducts and airflow outlets implemented in a bogie for a rail vehicle. They can be configured and implemented in other ways, for example in various contexts such as tramways and subway cars. For example, in the description, the bogie has two axles driven by a traction motor. Alternatively, the bogie may have only one driven axle and one non-driven axle.

Claims

1. It is mechanically attachable to the casing (12) of the self-ventilated traction motor (6, 7), a body (13) mountable on said casing (12) and substantially surrounding the longitudinal axis (17) of said traction motors (6, 7); an air duct (16) presenting an air flow inlet (14) at one end and an air flow outlet (15) at the other end; An airflow hood (9) for a self-ventilating traction motor (6, 7), comprising:

1. An airflow hood for a self-ventilated traction motor, characterized in that the airflow outlets (15) are directed downwards and, when the airflow hood (9) is mounted on the casing (12), the airflow hood (9) is located at a proximal axial end (11) of the casing (12) opposite a distal axial end (10) of the casing (12) at which a fan (19) is located and from which a rotatable motor shaft (18) projects axially to drive an axle (3, 4).

2. 2. An airflow hood for a self-ventilated traction motor according to claim 1, wherein the airflow outlets (15) are arranged asymmetrically with respect to a vertical axial plane containing the longitudinal axis (17) of the traction motor (6, 7).

3. the cooling airflow leaving the casing (12) enters the body (13) and leaves the airflow hood (9) by the airflow outlet (15) in a substantially tangential direction relative to a cylinder coaxial with the traction motor (6, 7); and / or the airflow outlet (15) is arranged substantially horizontally, facing downwards; 3. An airflow hood for a self-ventilated traction motor according to claim 1 or 2.

4. An airflow hood for a self-ventilated traction motor according to any one of claims 1 to 3, wherein the airflow outlet (15) is located on a side of the traction motor (6, 7) opposite the axle (3, 4) driven by the traction motor (6, 7).

5. the cross section of said air duct (16) gradually increases towards said airflow outlet (15), and / or the airflow outlet (15) extends over substantially all of the underside of the body (13) of the airflow hood (9); 5. An airflow hood for a self-ventilated traction motor as claimed in claim 4.

6. An airflow hood for a self-ventilated traction motor as claimed in claim 4 or 5, wherein the air duct (16) extends substantially along the side of the body (13) opposite the axles (3, 4).

7. the airflow outlet (15) is located on the side of the axle (3, 4) opposite the traction motor (6, 7), and / or said airflow outlet (15) is arranged substantially horizontally; An airflow hood for a self-ventilated traction motor according to any one of claims 1 to 3.

8. the air duct (16) extends past the body (13) to pass to the other side of the axle (3, 4); and / or the cross section of the air duct (16) gradually decreases towards the airflow outlet (15); 8. An airflow hood for a self-ventilated traction motor as claimed in claim 7.

9. - said air flow hood (9) is substantially U-shaped, said body (13) forming a first leg of said U-shaped air flow hood (9) and said air duct (16) forming a second leg of said U-shaped air flow hood (9); and The airflow hood for a self-ventilated traction motor according to claim 8, wherein the axle (3, 4) driven by the traction motor (6, 7) is arranged between the first and second legs of the U-shaped airflow hood (9).

10. A self-ventilated traction motor assembly comprising a casing (12) surrounding a rotatable motor shaft (18) which transmits a driving force to a gearbox (8), and a fan (19) attached to the rotatable motor shaft (18) on the side of the gearbox (8) and generating a cooling airflow (20) circulating longitudinally through a self-ventilated traction motor (6, 7), A self-ventilated traction motor assembly, characterised in that it further comprises an airflow hood (9) according to any one of claims 1 to 9 for guiding the exhaust (21) of the cooling airflow.

11. A railway bogie comprising a frame (2), at least one axle (3, 4) rotatably mounted on the frame (2), and at least one gearbox (8) mechanically connected to the at least one axle (3, 4), 11. A railway bogie, further comprising at least one self-ventilated traction motor assembly as claimed in claim 10 for driving said at least one gearbox (8), said traction motor being arranged parallel to and spaced apart from said corresponding axles (3, 4), said casing (12) being mechanically attached to said frame (2).

12. 12. The railway bogie of claim 11, further comprising two gearboxes (8), two axles (3, 4), and an upstream self-ventilated traction motor (6) and a downstream self-ventilated traction motor (7), each connected to a corresponding gearbox (8) for driving a respective axle (3, 4).

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