COOLING DEVICE FOR AN ELECTRIC DRIVE MOTOR OF A VEHICLE, CORRESPONDING DRIVE ARRANGEMENT, CORRESPONDING VEHICLE AND REPLACEMENT PROCEDURE

Description

[0001] The present invention relates to a device for cooling an electric traction motor of a vehicle.

[0002] The invention also relates to a motorization assembly comprising such a cooling device.

[0003] The invention also relates to a vehicle comprising such a motorization assembly.

[0004] The invention also relates to a method for replacing such a cooling device of a motor assembly.

[0005] The vehicle is, for example, a railway vehicle, or, alternatively, a motor, air or sea vehicle.

[0006] It is necessary to cool an electric traction motor when it is operating in order to avoid overheating and thus ensure its proper functioning.

[0007] Document FR 3 000 628 discloses a cooling device for a drive device for an aircraft wheel.

[0008] In addition, it is known to rigidly attach a fan to the electric traction motor in order to cool it during operation. The fan is directly coupled to the rotor of the electric traction motor and rotates at the same time as it. Thus, the fan creates an airflow that cools the electric traction motor by forced convection.

[0009] However, the performance of such a fan in terms of cooling, pressure losses and noise is not sufficient. Indeed, it is impossible to adjust the geometry of the fan for the entire operating range of the electric motor and it is impossible to control the rotation speed of the fan independently, especially in relation to the electric motor. In addition, the maintenance of such a fan is tedious because it requires disassembling the entire motor and may involve removing the motor.

[0010] One of the objectives of the invention is to propose a device for cooling an electric traction motor of a vehicle having improved cooling performance while reducing the noise generated by the operation of the fan and allowing easy maintenance.

[0011] For this purpose, the invention relates to a cooling device according to claim 1.

[0012] According to particular embodiments of the invention, the cooling device also has one or more of the characteristics of claims 2 to 5.

[0013] The invention also relates to a motorization assembly according to claim 6.

[0014] According to particular embodiments of the invention, the motorization assembly also has one or more of the characteristics 7 or 8.

[0015] The invention also relates to a vehicle, in particular a railway vehicle, comprising at least one motorization assembly as defined above.

[0016] The invention also relates to a replacement method comprising the following steps: supply of a motorization assembly as defined above, detachment and replacement of the cooling device with another cooling device as defined above.

[0017] The invention and its advantages will be better understood upon reading the following description, given solely as a non-limiting example, and made with reference to the appended drawings, in which: [ Fig 1 ] there figure 1 is a schematic side representation of a railway vehicle; and [ Fig 2 ] there figure 2 is a perspective view of a motor assembly on board the railway vehicle of the figure 1 ; [ Fig 3 ] there figure 3 is a perspective view of the cooling device of the motor assembly of the figure 2 ; And [ Fig 4 ] there figure 4 is a sectional view of the motor assembly of the figure 2 .

[0018] A railway system 2 comprising a railway infrastructure 4 and a railway vehicle 10 is illustrated in the figure 1 .

[0019] Rail infrastructure 4 includes 6 rails and 8 overhead lines.

[0020] The catenary 8 is an electrical power supply device suspended above the rails 6 and consisting of one or two electrically conductive contact wires and carrier cables.

[0021] Subsequently, only the railway vehicle 10 will be described but those skilled in the art will understand that the invention applies to any type of vehicle such as a motor vehicle, air vehicle or sea vehicle.

[0022] The railway vehicle 10 is configured to allow the transport of passengers and / or goods.

[0023] As visible on the figure 1 , the railway vehicle 10 comprises at least one passenger and / or goods transport car 12, a leading car 14 and at least one motorization assembly 16 on board the vehicle 10.

[0024] Advantageously, the vehicle 10 further comprises a tail car 18 located at the opposite end of the lead car 14.

[0025] The vehicle further comprises at least one pantograph 20 arranged on one of the cars 12, 14, 18. The pantograph 20 is an articulated device configured to capture an electric current by friction on the catenary 8.

[0026] Each car 12, 14, 18 extends in a longitudinal direction and has two longitudinal ends.

[0027] The vehicle 10 comprises bogies 17. Each bogie 17 supports a car 12, 14, 18 resting on this bogie 17 or supports two neighboring cars 12, 14, 18 resting by their neighboring longitudinal ends on this bogie 17 (this is then referred to as a “common bogie”).

[0028] Each bogie 17 comprises wheels 22 fixed to the bogie 17 by shafts not shown in the figures. The wheels 22 are configured to roll on the rails 6 and thus allow the movement of the railway vehicle 10.

[0029] The lead car 14 defines a leading end of the rail vehicle 10.

[0030] The lead car 14 is here a motor car or locomotive, configured to provide the motive power for the vehicle 10, i.e. to push or pull the cars 12.

[0031] For this purpose, the or one of the motorization assemblies 16 is installed in the lead car 14.

[0032] In an advantageous embodiment, the railway vehicle 10 is configured to travel in both directions. The tail car 18 is then also a locomotive capable of towing the other cars 12, 14.

[0033] One of the engine assembly(s) 16 is then loaded into the tail car 20.

[0034] Advantageously, one of the motorization assemblies 16 is furthermore embedded in at least one of the transport cars 12.

[0035] The motor assembly 16 extends mainly along a main axis A-A'.

[0036] The motor assembly 16 comprises an electric motor 24, a casing 26 surrounding the motor 24, at least one cooling channel 27 and a cooling device 28.

[0037] Advantageously, the motorization assembly 16 further comprises a speed measuring device 30 configured to measure the rotation speed of the electric motor 24.

[0038] The electric motor 24 is electrically powered by the electric current captured by the pantograph 20.

[0039] The electric motor 24 is a traction motor of the vehicle 10. The electric motor 24 is configured to convert the received electrical energy into mechanical energy allowing the rotation of the wheels 22 and thus the movement of the vehicle 10.

[0040] In the example illustrated on the figure 4 , the electric motor 24 is a three-phase electric machine comprising a rotor 32, a stator 34 and an external partition 35.

[0041] The rotor 32 is generally cylindrical in shape and extends along the main axis A-A'. The rotor 32 is rotatably mounted relative to the stator 34.

[0042] The stator 34 extends around the rotor 32.

[0043] Preferably, the rotating electrical machine 32 is a synchronous machine.

[0044] Alternatively, the rotating electrical machine 32 is a synchronous machine.

[0045] The outer partition 35 extends around the stator 34 and protects the interior of the electric motor 24.

[0046] The casing 26 comprises a wall 36 surrounding the motor 24.

[0047] The housing 26 includes a side wall 36A surrounding the engine 24, a front wall 36B and a rear wall 36C.

[0048] The section perpendicular to the main axis AA' of the side wall 36A has a generally rectangular shape, in particular square.

[0049] Alternatively, the section perpendicular to the main axis AA' of the side wall 36A has a generally circular or polygonal shape.

[0050] The front wall 36B is provided for mounting the cooling device 28.

[0051] The wall 36 is provided with at least one through opening 38 for the passage of an air flow for cooling the electric motor 24.

[0052] Advantageously, as visible on the figure 2 , the wall 36 comprises a plurality of openings 38.

[0053] The openings 38 are in particular arranged on the front face 36B of the wall 36.

[0054] Each cooling channel 27 extends to the periphery of the stator 34.

[0055] Each cooling channel 27 extends from one of the openings 38 and opens outside the casing 26 at the rear wall 36C. Each cooling channel 27 is thus configured to be supplied by the air flow via at least one of the opening(s) 38.

[0056] Each cooling channel 27 is located at the periphery of the engine 24.

[0057] In particular, each cooling channel 27 is in contact with the external partition 35 of the engine 24.

[0058] Advantageously, each cooling channel 27 extends along the main axis A-A'.

[0059] Thus, the cooling channels 27 extend along the main axis AA' from the front wall 36B to the rear wall 36C.

[0060] During operation of the electric motor 24, it produces heat which must be evacuated in order to ensure proper operation of the electric motor 24.

[0061] The circulation of the air flow in each cooling channel 27 is represented by the arrows visible on the figure 4 .

[0062] During this circulation, the air flow recovers the heat produced by the electric motor and evacuates it from the casing 26, towards the exterior of the vehicle 10.

[0063] The cooling device 28 is configured to cool the electric motor 20.

[0064] In particular, the cooling device 28 is configured to produce an air flow and send it into each opening 38 in order to cool the motor 24.

[0065] The cooling device 28 has a maximum transverse extent L of between 0.1 m and 1.6 m.

[0066] The cooling device 28 comprises a casing 40 and a motor fan 42.

[0067] The section perpendicular to the main axis AA' of the envelope 40 has a generally rectangular, in particular square, outline.

[0068] Alternatively, the section perpendicular to the main axis AA' of the envelope 40 has a contour of general circular or polygonal shape.

[0069] In particular, the casing 40 has a contour corresponding to that of the casing 26 when viewed along the main axis AA.

[0070] The casing 40 has a first face 48 and a second face 50 opposite the first face 48. The cooling device 28 is designed to be fixed to the casing 26 by applying the casing 40 against the casing 26, more particularly by applying the second face 50 against the casing 26.

[0071] The first face 48 advantageously has a generally convex shape, and preferably a profiled one.

[0072] The first face 48 has an air inlet 52 to allow the entry of air 52 inside the envelope 40.

[0073] The air inlet 52 advantageously has the shape of a circular opening, located for example substantially in the center of the first face 48.

[0074] Advantageously, the air inlet 52 has a maximum transverse extent D of between 20% and 70% of the maximum transverse extent L of the cooling device 28.

[0075] The second face 50 advantageously has a generally concave, hollow shape.

[0076] The second face 50 advantageously defines a cavity 54 located outside the cooling device 28.

[0077] The second face 50 has an air outlet 56. The air outlet 56 of the second face 50 is intended to be fluidically connected to at least one opening 38 of the casing 26 for supplying air to this opening 38.

[0078] Here, the second face 50 defines a single air outlet 56 of annular shape located substantially at the periphery of the second face 50.

[0079] The envelope 40 is for example made of a first part and a second separate part assembled with each other, the first part defining the first face 48 and the second part 50 defining the second face of the envelope 40.

[0080] The two parts of the casing 40 are fixed together, for example by means of screws.

[0081] The casing 40 is hollow and delimits an air channel 58 connecting the air inlet 52 to the air outlet 56.

[0082] The cooling device 28 is configured to generate the air flow in the air duct 58 between the air inlet 52 and the air outlet 56 and thus supply the opening(s) 38 with the air flow.

[0083] In particular, the cooling device 28 is configured to circulate an air flow axially relative to the main axis AA' through the air inlet 52, the air flow then flowing away from the main axis AA in the portion of the duct 58.

[0084] The ducting conduit 58 is configured to continuously reduce the velocity of the air flow between the air inlet 52 and the air outlet 56.

[0085] The pipe 58 is therefore a diffuser.

[0086] In particular, the speed of the air flow in the duct 58 is broken down into a tangential component and a radial component relative to the main axis A-A'. The tangential component is generally greater than the radial component. The slowing down of the tangential component follows a law inversely proportional to the distance from the main axis A-A'. The air flow slows down tangentially as it moves away from the main axis AA' while progressing towards the air outlet 56. The radial component of the speed varies according to the ratio between the section perpendicular to the air flow at the inlet of the air duct 58 and the section perpendicular to the outlet of the air duct 58.

[0087] The air duct 58 is dimensioned so that the absolute speed of the air flow at the air outlet 56 is lower than the speed of the air flow at the air inlet 54 thanks to the slowing down obtained on the tangential component of the speed, despite the possible increase in the radial speed.

[0088] This slowing down of the speed of the air flow in the air duct 58 makes it possible to convert the dynamic pressure of the air flow into useful static pressure. This recovery of static pressure makes it possible to compensate for the pressure losses of the air flow and to reduce the aeraulic noise of the cooling device 28 by avoiding sudden fluctuations in speed and pressure of the air flow due to shocks and turbulence.

[0089] The motor fan 42 is mounted inside the casing 40.

[0090] The fan motor 42 is configured to force air circulation from the air inlet 52 to the air outlet 56.

[0091] In particular, the fan motor 42 comprises a rotating electric machine 60 having a rotating shaft 62, and a set of blades 64 fixed to the rotating shaft 62.

[0092] The motor fan 42 is configured to suck in an air flow axially relative to the main axis AA through the inlet 52 and circulate this air flow mainly radially relative to the main axis AA in the portion of the duct 58.

[0093] The cooling device 28 is configured to be fixed by removable fixing means 66 on the casing 26 by applying the second face 50 of the casing 40 against the wall 36 of the casing 26.

[0094] When the cooling device 28 and the casing 26 are fixed together, the air outlet 56 faces an opening 38.

[0095] The fixing means 66 are for example screws. In the example of the figure 2 , the cooling device 28 is in particular fixed by four screws arranged at the four corners of the casing 40.

[0096] Optional, as shown in the Figures 3 And 4 , the cooling device comprises fins 44 located inside the pipe conduit 58.

[0097] The fins 44 are fixed relative to the casing 40.

[0098] The orientation of the fins 44 is determined as a function of the angle of incidence of the air flow at the fins 44. This incidence depends on the ratio between the tangential component and the radial component of the air flow speed.

[0099] The fins 44 are configured to direct the airflow and to limit swirling of the airflow. The fins 44 further participate in slowing the airflow in the duct 58.

[0100] The cooling device preferably comprises an electrical power supply 46 for supplying electricity to the motor fan 42, more particularly for supplying electricity to the electric machine 60, thus enabling the blades 64 to rotate.

[0101] Advantageously, the electrical power supply 46 is independent of the electrical power supply of the electric motor 24.

[0102] Thus, the rotation speed of the fan motor 42 can be independent of the rotation speed of the rotor 32 of the motor 24.

[0103] The speed measuring device 30 is configured to measure the rotational speed of the rotor 32 of the electric motor 24.

[0104] The speed measuring device 30 is located outside the casing 26, on the wall 36 of the casing 26 provided with the openings 38 and designed to receive the cooling device 28.

[0105] When the cooling device 28 is mounted on said wall 36 of the casing 26, the speed measuring device 30 is received in the cavity 54 of the second face 50, between the second face 50 and the wall 36 of the casing 26.

[0106] The speed measuring device 30 comprises for example a code wheel mounted on one end of the output shaft of the electric motor projecting from the wall 36, and a speed sensor suitable for measuring the rotation speed of the code wheel and located on the wall 36 of the casing 26.

[0107] A method of replacing a cooling device 28 will now be described.

[0108] Initially, a motorization assembly 16 is mounted on board a railway vehicle 10 and provides mechanical energy for the movement of the vehicle 10.

[0109] Then, when an operation to replace the cooling device 28 of the motor assembly 16 is necessary for maintenance reasons for example, the first cooling device 28 is detached from the casing 26.

[0110] In particular, the removable fixing means 66 are removed in order to allow the first cooling device 28 and the casing 26 to be separated.

[0111] Then, the method comprises a step of replacing the first cooling device 28 with another cooling device 28.

[0112] If accessibility around the engine 24 allows it, the replacement is carried out without removing the engine 24 from the railway vehicle 10.

[0113] The other cooling device 28 is fixed to the casing 26 via the fixing means 66.

[0114] The motor assembly 16 is then operational again.

[0115] It is therefore understood that the present invention presents a certain number of advantages.

[0116] The invention allows easy and rapid replacement of the cooling device 28 only by detaching the fixing means 66 and without having to dismantle the casing 26.

[0117] Thus, maintenance of the cooling device 28 is facilitated and allows increased operational availability of the electric motor 24.

[0118] The invention further allows replacement of the cooling device 28 with another cooling device 28 more suited to the intended operation of the engine 24. In particular, it is possible to adapt the cooling device 28 according to the intended operating point of the engine 24 by choosing the one whose geometry of the pipe duct 58 is the most suitable.

[0119] In addition, the cooling device 28 is decoupled from the motor 24. The rotational speed of the motor fan 42 is therefore independent of the rotational speed of the rotor 32 and can thus be optimally adapted to the operating point of the motor 24.

[0120] Thus, a significant improvement in the cooling performance of the engine 24 by the cooling device is achieved.

[0121] The invention also therefore makes it possible to increase the service life of the motor 24 and avoids any incident due to overheating thereof.

[0122] Finally, the recovery of static pressure in the distribution duct 58 makes it possible to compensate for pressure losses and significantly reduces airflow noise.

Claims

1. Cooling device (28) for an electric traction motor (24) of a vehicle (10), in particular a rail vehicle, the electric motor (24) being surrounded by a casing (26) having a wall (36) provided with at least one opening (38) for the entry of a flow of air for cooling the electric motor (24), the cooling device (28) comprising: - an casing (40) having a first wall (48) and an opposite second wall (50), the casing (40) delimiting an air duct (58) connecting an air inlet (52) situated on the first wall (48) to a single annular air outlet (56) defined by the second wall (50) located on the second wall (50), substantially at the periphery of the second wall (50); and - a motorised fan (42) mounted inside the casing (40) and configured to force the flow of air from the air inlet (52) to the air outlet (56); the cooling device (28) being configured to be removably fixed to the casing (26) by applying the second wall (50) of the casing (40) against the wall (36) of the casing (26), the air outlet (56) facing the opening(s) (38) when the cooling device (28) is fixed to the casing (26), the cooling device (28) being configured to generate the air flow in the air duct (58) between the air inlet (52) and the air outlet (56) and to circulate an air flow through the air inlet (52) axially with respect to a main axis (A-A') of a motor assembly comprising an electric motor (24) and the cooling device (28), the motorised fan (42) being configured to suck in the flow of air through the air inlet (52) and to circulate this air flow mainly radially with respect to axis (A-A') in the air duct (58), the air flow then flowing away from the main axis (A-A') in the air duct (58).

2. A cooling device (28) as claimed in claim 1, wherein the air duct (58) is configured to continuously reduce the velocity of the airflow between the air inlet and outlet.

3. Cooling device (28) according to any of the preceding claims, further comprising a plurality of fins (44) arranged in the air duct (58).

4. Cooling device (28) according to any of the preceding claims, comprising an electrical supply (46) for the motorised fan (42) independent of an electrical supply to the electric motor (24).

5. A cooling device (28) according to any one of the preceding claims, in which the second wall (50) of the casing (40) defines a cavity (54).

6. A motorisation assembly (16) comprising: - an electric traction motor (24) for a vehicle (10), - a casing (26) surrounding the electric motor (24), the casing (26) comprising a wall (36) provided with at least one through opening (38) for the passage of a flow of air for cooling the electric motor (24); - a cooling device (28) according to any one of the preceding claims, the cooling device (28) being removably fixed to the casing, the second side (50) of the casing (40) being applied against the wall (36) of the casing (26) so that the flow of air leaving through the air outlet (56) of the casing (40) feeds the opening(s) (38) in the said wall (36).

7. A motorisation assembly (16) as claimed in claim 6, wherein the electric motor (24) comprises a rotor (32) extending along the main axis (A-A') and a stator (34) extending around the rotor (32), the motorisation assembly (16) comprising at least one cooling channel (27) fed by the opening(s) (38) and extending around the periphery of the stator (34).

8. A motorisation assembly (16) according to claim 7, the cooling device (28) being according to claim 5, wherein the motorisation assembly (16) comprises a device for measuring the speed (30) of rotation of the rotor (32) of the electric motor (24), the speed measuring device (30) being arranged in the cavity (54) between the second side (50) and the wall (36) of the casing (26).

9. A vehicle (10), particularly a railway vehicle, comprising at least one motorisation assembly (16) according to any of claims 6 to 8.

10. A replacement method including the following steps: - supply of a motorisation assembly (16) according to any one of claims 6 to 8; - detachment and replacement of the cooling device (28) by another cooling device (28) according to any one of claims 1 to 5.