railway vehicle motor bogie

Abstract

Motorized bogie of a railway vehicle Motorized bogie (1) of a railway vehicle comprising two mounted axles (4) each comprising a pair of wheels (2), at least one motor (25) fixed to the chassis (6) and extending between the wheels (2) of the mounted axle and driving the rotation of said mounted axle (4) by means of a coupling and a reduction gear, one of the axle boxes housing the reduction gear of the motor (25), the motor (25) being movable in rotation about a motor axis (M), characterized in that the axis (M) of the motor (25) is located at an altitude (h) lower than an altitude (H) of the axis (E) of the mounted axle (4), the altitude being taken along a vertical axis (Z) perpendicular to the longitudinal axis and to the axle axis (E) from a horizontal plane (P) perpendicular to the vertical axis (Z) and tangent to the wheel (2) in the lower part of the bogie (1). Figure for the abbreviation: Figure 2

Description

Description Title of the invention: Railway vehicle motor bogie The present invention relates to a motor bogie for a railway vehicle comprising two mounted axles, each comprising a pair of wheels, each mounted axle extending along an axle axis, said mounted axles being connected to each other by a chassis comprising at least two longitudinal members extending substantially parallel to a longitudinal axis and resting on axle boxes of each mounted axle, said boxes being disposed between the wheels of said mounted axle, at least one motor fixed to the chassis and extending between the wheels of the mounted axle and driving the rotation of said mounted axle by means of a coupling and a reduction gear, one of the axle boxes housing the reduction gear of the motor, the motor being free to rotate about a motor axis. In a railway vehicle, and in particular in a railway vehicle intended for intra-urban transport such as trams, it is desirable to limit the bulk of the bogies in order to increase the internal space accessible to passengers in the cars, and in particular to provide a wide corridor, while maintaining a small footprint of the railway vehicle on the track. Reducing the bogies' footprint under the body allows for a low floor, meaning one that extends at roughly the same level across the entire surface of the rail vehicle and is relatively close to the ground. A "low-floor vehicle" is defined as one where the maximum floor height above the ground does not exceed 0.35 m, and the maximum floor slope is 10%. This allows level access to the low-floor vehicle from a sidewalk or platform slightly raised above the track on which the vehicle travels. This also facilitates the movement of passengers between cars and access to the vehicle from the outside, particularly for passengers with mobility difficulties, while maximizing the number of seats installed at the bogie. In a railway vehicle, each powered bogie is equipped with means for rotating each axle. These drive means include at least one motor, at least one gearbox, and a mechanical device ensuring the transmission of the motor torque from the motor to the axle, and the transmission of the braking torque from the axle to the motor, while allowing the relative movements between the motor and the axle induced by the primary suspensions. The bogie axles are generally connected by an "outer" frame, in which the side members are arranged outside a space delimited by the wheels, or by an "inner" frame, in which the side members are arranged inside a space delimited by the wheels, i.e., between the wheels, on axle boxes. also arranged within the space delimited by the wheels. The inner chassis helps to reduce the mass of the bogie and lower its manufacturing costs. In order to reduce the transverse bulk of the bogie, it is known to place the motor(s) in the central space of the chassis. To reduce vertical forces in the track, it is advantageous to decrease unsprung masses. To facilitate the integration of drive systems, it is advantageous to reduce bulk. The so-called "semi-suspended motor" drive system traditionally consists of a motor that oscillates on the axle via two bearings, and to which a gearbox housing is attached. The motor output pinion meshes with a wheel fixed to the axle. A articulated reaction rod absorbs the torque and compensates for the vibrations caused by movement between the bogie frame and the axle. This transmission is simple to implement but results in high unsprung mass, which limits the vehicle's speed. In the so-called "hollow shaft" drive, the gearbox and motor are rigidly connected and fixed to the bogie frame. Torque is transmitted between the gearbox output bearing and the axle via a hollow shaft, which also compensates for the play caused by movement between the bogie frame and the axle. This transmission increases the bogie's overall size in the vehicle's direction of travel. The space occupied by the hollow shaft on the axle also generally necessitates the addition of an intermediate gear to the gearbox. This solution allows the vehicle to travel at high speeds, but it is complex to implement because it requires a hollow bearing at the gearbox output, connections between this bearing and the hollow shaft on the gearbox side, as well as connections between the axle and the hollow shaft. The so-called "semi-suspended gearbox" drive is a compromise in terms of unsprung mass and complexity between the two previous drive types. The motor is fixed to the bogie frame, and the gearbox is fixed on one side, pivoting on the axle, and connected on the other side to the bogie frame by a reaction rod. A mechanical coupling connects the motor shaft to the gearbox input bearing and accommodates the suspension travel between the motor output and the gearbox input. In the case of a motorized bogie with an internal frame, there is little space in the transverse direction to house a motor. A first state-of-the-art solution that allows for housing a powerful motor and the associated transmission, while limiting unsprung mass, is the hollow shaft suspension, which is complex to implement, as described above. A second known solution is to house the reducers inside the boxes axles and to integrate a secondary suspension in stirrup-shaped connecting rods linking the side members of the half-frames, as described in document EP 2 258 596 Al. However, these solutions are not suitable for low-floor vehicles. One of the aims of the invention is to overcome these disadvantages by proposing a compact bogie, with reduced mass, comprising limited unsprung masses and adapted to a low-floor vehicle. For this purpose, the invention relates to a bogie of the aforementioned type, in which the motor axis is located at an altitude lower than the altitude of the axis of the mounted axle, the altitude being taken along a vertical axis perpendicular to the longitudinal axis and to the axle axis from a horizontal plane perpendicular to the vertical axis and tangent to the wheel in the lower part of the bogie. Depending on other characteristics of the bogie, taken alone or in any technically possible combination: - the reducer comprises at least a first gear that rotates about a first axis substantially perpendicular to the longitudinal axis and a second gear that rotates about a second axis substantially perpendicular to the longitudinal axis, the first gear and the second gear being adapted to cooperate with each other; - each gear comprises a pinion and a toothed ring, the toothed rings each having helical teeth; - a ratio between the result of the difference between the altitude of the mounted axle axis and the altitude of the motor axis, and a wheel diameter when worn is greater than 1%, preferably 3%; - the bogie comprising a braking system including at least one braking device mounted on at least one of the wheels outside the space delimited by the wheels; - the braking system includes a braking device mounted on one of the two wheels on each longitudinal side of the bogie outside the space delimited by the wheels, the other wheel on each longitudinal side of the bogie preferably being without a braking device; - the braking system comprises four braking devices, each mounted on a respective wheel outside the space delimited by the wheels; - the bogie includes a primary suspension arranged between the chassis and each mounted axle, and configured to allow relative vertical movement of the chassis with respect to the mounted axles; - the bogie comprises two motors, each motor driving one of the respective axles in rotation via a coupling and a reduction gear, each engine extending between the wheels of said axle. The invention also relates to a railway vehicle comprising at least one bogie as described above, the body preferably comprising a lowered floor, extending substantially at the same level at the bogie. Other aspects and advantages of the invention will become apparent from the following description, given by way of example and with reference to the accompanying drawings, in which: - [fig.1] [fig.1] is a schematic perspective representation of a railway vehicle bogie according to the invention, - [fig.2] [fig.2] is a schematic side view representation of one of the two mounted axles and a motor of the bogie of [fig.1], and - [fig.3] The [fig.3] is a schematic top view of one of the two mounted axles and a motor of the bogie of the [fig.1], detailing the transmission between said motor and said mounted axle. In the description, the terms "vertical" and "horizontal" are defined with respect to a bogie mounted on a railway vehicle. Thus, a horizontal plane is substantially parallel to the plane in which the axles extend, and a vertical plane is substantially parallel to the plane in which the wheels extend. The term "longitudinal" is defined with respect to the direction in which a railway vehicle extends in a horizontal plane, and the term "transverse" is defined with respect to a direction perpendicular to the longitudinal direction in a horizontal plane. With reference to [Fig. 1], a powered bogie 1 of a railway vehicle (not shown) is described, for example, a guided land vehicle. In particular, the vehicle is a low-floor vehicle, for example, a tram or a self-propelled train. Preferably, the lowered floor extends to approximately the same level at the level of bogie 1. The bogie 1 comprises two mounted axles 4, each having a pair of wheels 2. The mounted axles 4 are connected to each other by a frame 6, called the inner frame, which carries the mounted axles 4. By inner frame, it is understood that the frame 6 extends between the wheels 2 in the transverse direction without "extending" beyond them. Each mounted axle 4 extends along an axle axis E. The chassis 6 comprises two longitudinal members 10, extending substantially longitudinally, connected to each other by two cross members 12, extending substantially transversely. Each mounted axle 4 has axle boxes 14, 14°, said axle boxes 14, 14' being arranged substantially against the wheels 2 of the axle 4, between said wheels 2. Each longitudinal member 10 has two longitudinal ends 15, each of the ex- longitudinal openings 15 resting on one of the respective axle boxes 14, 14' of the corresponding mounted axle 4. A primary suspension element 16 is for example interposed between each longitudinal end 15 of a longitudinal member 10 and the axle box 14, 14' on which the longitudinal end 15 of said longitudinal member 10 rests. The primary suspension element 16 is for example made by two rubber pads, for example placed respectively between the longitudinal member 10 and each axle box 14, 14°. This primary suspension element 16 allows for relative vertical movement of the chassis 6 with respect to the mounted axles 4; that is, the chassis 6 is mobile and suspended relative to the mounted axles 4 in a substantially vertical direction. The axle boxes 14 and 14" are connected to the chassis 6 by elastic joints 13 and 13°. The primary suspension thus formed by the primary suspension elements 16, the axle boxes 14 and 14°, and the joints 13 and 13°, is called a swing arm type suspension. The primary suspension 16 mainly takes over the vertical travel. The primary suspension 16 is particularly compact. It also has the advantage of allowing a reduction in unsprung mass, an important advantage especially in the case of a motorized bogie. The bogie described is powered, that is to say that at least one of the axles 4 is driven in rotation by a motor 25. Each motor 25 is arranged transversely, that is to say that its rotation shaft extends parallel to the mounted axle 4 which it drives, along a motor axis M. Motor 25 is notably an asynchronous type motor. Preferably, the 25 engine is water-cooled. Such a bogie architecture makes it possible in particular to limit the angular clearances between the axis M of the motor 25 and the axis of the mounted axle 4. The motor 25 is for example fixed relative to the chassis of the bogie 1. The motor 25 is for example fixed to a cross member 12 of the chassis 6 by two fixing pieces 26 each having substantially a right-angled shape, and extends in the vicinity of the mounted axle 4 which it drives, substantially between the two wheels 2. As can be seen in [fig.2], the axis M of the motor 25 is located at an altitude h lower than an altitude H of the axis E of the mounted axle 4, the altitude being taken along a vertical axis Z perpendicular to the longitudinal axis A and to the axle axis E and from a horizontal plane (P) perpendicular to the vertical axis Z and tangent to the wheel 2 in the lower part of the bogie 1. Certain parameters must be taken into account when designing bogie 1, including wheel wear 2, primary suspension sag, and bogie dimensions. During the life of bogie 1, wheels 2 tend to wear out, and their diameter is reduced as a result of this wear. The altitude H of the axis E of the respective mounted axle 4 decreases with the wear of the wheels 9. According to a particular embodiment, the diameter of a new wheel is approximately 660 mm. The diameter dl of a worn wheel 2 is approximately 580 mm. The wheel diameter varies between these two values ​​depending on the degree of wear. During driving, the primary suspension components constantly compress and rebound. According to the embodiment described, the primary suspension slump is at most about 15 mm. The bogie 1 clearance is defined as the minimum height at which all elements of the bogie, except the wheels, must be located for safety reasons. According to the embodiment described, the template is for example approximately 80 mm. Therefore, all elements of bogie 1, except for wheels 2, when not in motion, must be at an altitude at least equal to the sum of the clearance and the primary suspension sag. The engine 25 must therefore be located at an altitude at least equal to the sum of the dimensions and the primary suspension sag. According to the embodiment described, this sum is approximately 95 mm. According to this embodiment, the axis M of the motor 25 is located at an altitude h less than at least 20 mm from an altitude H of the axis E of the mounted axle 4, for example about 25 mm. According to this embodiment, the motor 25, for example, has a diameter d2 taken along the vertical Z direction of approximately 320 mm and a length taken along the axis M of the motor 25 of approximately 750 mm. A radius r2 of the motor 25 taken along the vertical Z direction of approximately 320 mm is thus approximately 160 mm. Advantageously, the sum of the bogie 1 gauge, the primary suspension sag and the radius r2 of motor 25 is less than the radius rl of the worn wheel 2. Advantageously still, a ratio between the result of the difference Hh between the altitude H of the axis E of the mounted axle 4 and the altitude h of the axis M of the motor 25, and a diameter dl of the wheel 2 when it is worn is greater than 3%, preferably greater than 5%. The maximum rotational speed of the engine 25 is, for example, approximately 5900 rpm for a semi-worn wheel at a vehicle speed of approximately 80 km / h. The use of such motors makes it possible to arrange the floor with a slope that is not too steep. As shown in [fig.3], a reduction gear 28 is placed in one of the axle boxes 14 of the mounted axle 4 driven by the motor 25. The bearings 38 of the axle box 14 also serve as bearings for a toothed ring of the reduction gear 28. As a result, the reduction gear 28 can be placed as close as possible to the wheel 2. The arrangement of the reduction gear 28 in an axle box 14 makes it possible to increase the aisle width of the railway vehicle, and to increase the length of the motor 25. The reduction gear housing thus acts as an axle box. According to a particular embodiment, the reduction ratio of the reducer 28, defined by the ratio between the input speed and the output speed, is between 6.5 and 10, for example substantially equal to 8. Such an arrangement allows simplified access to the wheels and places the bogie braking system outside the space delimited by the wheels, as will be described later. As shown in [fig.3], a coupling 30 is arranged between the motor 25 and the reducer 28. This coupling is for example crowned teeth, or is of any other type absorbing small clearances between the bogie frame and the axle. The training method is described below: The motor's rotation shaft 25 is linked at the output to the input of the coupling 30. The output of the coupling 30 is linked to a first gear 32. The first gear 32 includes, for example, a pinion 32a and a toothed ring 32b. The first gear 32 of the reducer 28 is linked to a second gear 33. The second gear 33 includes, for example, a pinion 33a and a toothed ring 33b. The first gear 32 of the reducer 28 is mobile in rotation around a first axis substantially perpendicular to the longitudinal axis A. The second gear 33 of the reducer 28 is mobile in rotation around a second axis substantially perpendicular to the longitudinal axis A. The first gear 32 of the reducer 28 and the second gear 33 of the reducer 28 have helical teeth. The crown 33b of the second gear 33 of the reducer 28 is wedged on the mounted axle 4. Of course, in the example described the reducer 28 includes two gears 32, 33 but could include more gears without departing from the spirit of the invention. The mounted axle 4, and in particular its wheels 2, is driven in rotation by the motor 25. The mounted axle 4 rotates by means of bearings 38, which are arranged in axle boxes 14, 14°, As the coupling 30 is close to the elastic joints 13, 13° of In the primary suspension, movement is minimized. These small movements allow for the installation of a toothed coupling between the motor and the reducer, which requires little angular movement. Such a transmission arrangement is particularly compact. The motor bogie according to the invention thus comprises a lightweight inner frame 6, a suspended motor 25, and a semi-suspended reduction gear 28, as well as a simple transmission to implement. In addition, bogie maintenance is facilitated by the accessibility of the wheels. The transmission is also of reduced length thanks to the reduced vertical travel provided by the primary suspension 16 at the coupling 30. Bogie 1 includes a braking system 48. The braking system 48 includes at least one braking device 50 mounted on a wheel 2 outside the space delimited by the wheels 2. Preferably, the braking system 48 includes at least one braking device 50 mounted on a wheel 2 of each axle mounted 4 and on each longitudinal side of the bogie 1 outside the space delimited by the wheels 2. Each braking device 50 comprises a disc 52 and a brake caliper 54 acting on the disc 52. Disc 52 has a smaller diameter than wheel 12. Disc 52, for example, is made of cast iron or steel. The disc 52 is connected to the associated wheel by a rigid link 58, the disc 52 and the wheel 2 being fixed in rotation around the axis of the mounted axle 4. The rigid link 58 connects the center of the wheel 12 and the center of the disc 52, the rigid link 58 extending in a transverse direction. The rigid link 58 is here formed from a part of the mounted axle structure 4, that is to say that the mounted axle structure 4 extends between the braking devices 52 mounted outside the space delimited by the wheels 2 of a pair and passes through said wheels 2 of the pair. For each braking device 50, the brake caliper 54 has two pads 60 capable of coming into friction with each side of the disc 52 in a braking position. Outside of the braking position, the pads 60 do not rub against the disc 52. The 60 plates, for example, are made of composite material or sintered material. Each axle mounted 4 is devoid of a brake disc between the two wheels 2. The fact that the reduction gear 28 is located in the axle box 14 makes it possible to install up to four braking devices 50 distributed outside the space delimited by wheels 2. The reduction gear does not take up the space of a brake disc, thus freeing up room. Having two brake discs per axle is very advantageous, especially in the case of a railcar. The railway vehicle bogie according to the invention allows for a fully lowered floor, while maintaining a sufficiently small transverse footprint for the railway vehicle.

Claims

Demands

1. Bogic motor (1) of a railway vehicle comprising two axles mounted (4) each comprising a pair of wheels (2), each axle mounted (4) extending along an axle axis (E), said mounted axles (4) being connected to each other by a chassis (6) comprising at least two longerons (10) extending substantially parallel to a longitudinal axis gitudinal (A) and resting on axle boxes (14, 14') of each axle mounted (4), said boxes (14, 14”) being arranged between the wheels {2) said axle mounted (4), at least one motor (25) fixed to the chassis (6) and extending between the wheels (2) of the mounted axle (4) and driving the rotation of said axle mounted (4) by means of a coupling (30) and a reducer (28), one of the axle boxes (14) housing the reducer (28) of the motor (25), the motor (25) being free to rotate around a motor axis (M), characterized in that the axis (M) of the engine (25) is located at an altitude (h) lower than an altitude (H) of P'axe (E) of the mounted axle (4), the altitude being taken along an axis vertical (Z) perpendicular to the longitudinal axis (A) and to the axle axis (E) from a horizontal plane (P) perpendicular to the vertical axis (Z) and tangent to the wheel (2) in the lower part of the bogie (1).

2. Motor bogie (1) according to claim 1, wherein the reducer (28) includes at least one first rotating gear (32) around a first axis substantially perpendicular to the longitudinal axis gitudinal (A) and a second gear (33) movable in rotation around of a second axis substantially perpendicular to the longitudinal axis (A), the first gear (32) and the second gear (33) being specific to to cooperate with each other.

3. Motor bogie (1) according to claim 2, wherein each gear (32, 33) includes a pinion (32a, 33b) and a crown toothed (32b, 33b), the toothed crowns (32b, 33b) each presenting helical teeth.

4. Motor bogie (1) according to any one of claims 1 to 3, in which is a ratio between the result of the difference between the altitude (H) of the axis (E) of the wheelset (4) and the altitude (h) of the axis (M) of the motor (25), and a diameter of the wheel (2) when worn is greater than 1%, preferably to 3%.

5. Motor bogie (1) according to any one of claims 1 to 4, the bogie (1) comprising a braking system (48) comprising at least a braking device (50) mounted on at least one of the wheels (2) to outside the space delimited by the wheels (2).

6. Motor bogie (1) according to claim 5, wherein the system of braking (48) includes a braking device (50) mounted on one of the two wheels (2) on each longitudinal side of the bogie (1) on the outside of the space delimited by the wheels {2), the other wheel (2) on each side longitudinal of the bogie {1) being preferably devoid of a device braking (50).

7. Motor bogie (1) according to claim 5, wherein the system of braking (48) includes four braking devices (50) mounted each on a respective wheel (2) outside the space delimited by the wheels (2).

8. Motor bogie (1) according to any one of claims 1 to 7, ca- characterized in that it comprises a primary suspension arranged between the chassis (6) and each mounted axle (4), and configured to allow a relative vertical displacement of the chassis (6) with respect to the axles mounted (4).

9. Motor bogie (1) according to any one of claims 1 to 8, ca- characterized in that the bogie (1) comprises two motors (25), each motor (25) driving in rotation one respective of the axles (4) by via a coupling (30) and a reducer (28), each motor (25) extending between the wheels (2) of said axle (4).

10. | Railway vehicle, characterized in that it comprises at least one bogie motor (1) according to any one of claims | to 9, and a vehicle body carried by the bogie (1), the body comprising preferably a lowered floor, extending substantially to the same level at the right of the bogie (1).