FR3049253A1 - RAILWAY VEHICLE BOGIE COMPRISING A LOWER CHASSIS - Google Patents

Abstract

The bogie (10) comprises a frame (12) comprising at least one spar (16) extending in a longitudinal direction and at least one wheel (14) mounted on an axle box (18) and being rotatable by to said axle box (18) about an axis of rotation (A), said axle box (18) being attached to the spar (16) by a primary suspension device (20) comprising an elastic member ( 28) arranged to allow a clearance in a direction of elevation of the frame (12) relative to the axle box (18) and the wheel (14), said elastic member (28) extending between a plate ( 30) secured to the axle box (18) and a bearing surface (32) integral with the frame (12). The bearing surface (32) and the elastic element (28) are arranged in the longitudinal direction between the axis of rotation (A) and the spar (16).

Description

Railway vehicle bogie with lowered chassis

The present invention relates to a railway vehicle bogie, of the type comprising a chassis comprising at least one spar extending in a longitudinal direction and at least one wheel, said wheel being mounted on an axle box and being rotatable relative to at said axle box about an axis of rotation substantially perpendicular to the longitudinal direction, said axle box being fixed to the spar by a primary suspension device comprising an elastic element arranged to allow a movement in a direction of elevation of the chassis relative to the axle box and to the wheel, the elevation direction being substantially perpendicular to the longitudinal direction and to the axis of rotation, said elastic element extending between a plate integral with the box; axle and a support surface secured to the chassis. The invention also relates to a railway vehicle comprising such a bogie.

In a railway vehicle bogie, it is known to suspend the chassis of the bogie relative to the axles by means of primary suspensions extending between the axle boxes on which the wheels are mounted mobile in rotation and the longitudinal members of the bogie. . Such primary suspensions allow to damp the deformations, such as left lanes, between the axles and the chassis.

As shown in FIG. 1 which shows part of a conventional bogie, each primary suspension generally comprises an elastic element 1, such as a helical spring, extending between a plate 2 disposed on the axle box 4 and a bearing surface 6 extending under a longitudinal member 8 of the frame. Thus, a travel in a direction of elevation, substantially vertical when the rail vehicle is traveling, is allowed between the axle and the frame, which allows the desired damping. Such an arrangement is necessary to allow the recovery of the forces applied by the mass of the vehicle extending above the bogie. However, such a bogie architecture requires that the spar 6 extends above the axle box, which increases the size of the bogie in the direction of elevation.

Such a size can be inconvenient, especially for railway vehicles whose cars have two floors, which requires a lower floor. In the case of a bogie too bulky, it is not possible to have two floors to the right of the bogie without greatly limiting the volume of the passenger compartment, which is uncomfortable for the movement of passengers. Some railway vehicles plan to have only one passage, called the interconnecting passage, on a single floor at the bogies, which requires a stairway to pass from one car to another when a passenger is not at the level at which the interconnect pass extends. One of the aims of the invention is to overcome these disadvantages by proposing a bogie whose size, especially in the direction of elevation, is reduced. For this purpose, the invention relates to a bogie of the aforementioned type, wherein the plate, the bearing surface and the elastic element are arranged in the longitudinal direction between the axis of rotation and the spar.

By shifting the plate, the bearing surface and the elastic member so that they extend in the longitudinal direction between the axis of rotation and the spar, the space above the axle box is released since the spar must not necessarily extend above the axle box. Travel is always allowed in the direction of elevation between the axle box and the spar.

According to another characteristic of the bogie according to the invention, the primary suspension device further comprises a lower connecting rod hinged on the one hand to a lower hinge point of the spar and on the other hand to a lower hinge point of the spider. axle box and an upper link articulated firstly to an upper articulation point of the spar and secondly to an upper articulation point of the axle box, the lower articulation point and the point of upper articulation of the spar, respectively of the axle box, extending one below the other in the direction of elevation, the plate, the bearing surface and the elastic element being arranged in the direction of elevation between the lower link and the upper link.

The lower and upper connecting rods make it possible to take up the forces applied between the chassis and the rolling part of the bogie according to the elevation direction and to recover the torque generated by the cantilevered mounting of the elastic element with respect to the axis. of rotation.

According to other features of the bogie according to the invention, taken separately or in any possible technical combination: - the lower hinge point and the upper hinge point of the axle box are arranged on either side the axis of rotation in the direction of elevation; - The lower hinge point and the upper hinge point of the axle box are arranged on either side of the axis of rotation in the longitudinal direction; the axes of articulation of the lower and upper connecting rods to the spar and to the axle box are substantially parallel to the axis of rotation; - The lower link and the upper link are of the same length; - The bearing surface extends in the longitudinal direction from a longitudinal end of the beam to the axle box, said longitudinal end extending opposite the axle box in the longitudinal direction; - The spar extends to a height, measured in the direction of elevation, less than the height of the wheel; the elastic element comprises at least one helical spring with axis extending in the direction of elevation; and the chassis comprises at least two longitudinal members each of the longitudinal ends of which is fixed to an axle box by a primary articulation device, a wheel being rotatably mounted on each of said axle boxes, the elastic elements of the devices. primary articulation each extending between an axle box and a longitudinal end of a spar in the longitudinal direction. Other aspects and advantages of the invention will appear on reading the description which follows, given by way of example and with reference to the appended drawings, in which: FIG. 1 is a diagrammatic side view of a part of a bogie according to the prior art, - Figure 2 is a schematic side view of a portion of a bogie according to the invention, and - Figure 3 is a simplified schematic top view of a bogie according to the invention.

In the description, the term "longitudinal" is defined with respect to the direction of movement of a railway vehicle on rails. The term "transverse" is defined in a direction perpendicular to the longitudinal direction and corresponding to the direction in which the rails are spaced. The term "elevation" is defined in a direction perpendicular to the longitudinal direction and the transverse direction. When the railway vehicle is traveling on horizontal rails, the longitudinal and transverse directions are substantially horizontal and the elevation direction is substantially vertical. The terms "below" and "above" are defined relative to the elevation direction.

Referring to Figures 2 and 3, a bogie 10 comprises a frame 12 and at least one wheel 14 connected to a spar 16 of the frame 12 via an axle box 18 and a suspension device primary 20.

According to the embodiment shown in FIG. 3, the bogie 10 comprises, in a conventional manner, four wheels 14 each connected to the chassis 12 via an axle box 18 and a primary suspension device 18. The wheels 14 are connected in pairs by a shaft 22 so as to form two axles each mounted to rotate in a pair of axle boxes 18. The frame 12 comprises two longitudinal members 16 each connecting one of the axle boxes 18 of a pair to one of the axle boxes 18 of the other pair of axle boxes 18. The longitudinal members 16 are for example connected to one another by two cross members 24. However, this structure The particular truck is only given by way of example and other structures could be envisaged. Thus, each wheel could be rotatably mounted in an axle box independently of the others. The bogie could comprise more than two longitudinal members, for example articulated between them. The wheels have been shown as extending outside the bogie 10, but they could be arranged inside. The bogie may be motorized or not, that is to say that it may or may not comprise one or two motors for rotating one or both axles of the truck 10.

In the following description only the relationship between a wheel, an axle box and a spar will be described, this relationship being identical for all wheels, axle boxes and spars.

The wheel 14 is rotatable relative to the axle box 18 about a substantially transverse axis of rotation A and has a height h, measured in the direction of elevation, equal to the diameter of the wheel 14. The height h is for example substantially between 750 mm and 1250 mm.

The spar 16 extends in a longitudinal direction at a height h ', measured in the direction of elevation, less than the height h of the wheel. By lower is meant that the spar 16 has no portion extending to a height greater than that of the wheel. The spar 16 does not include any portion rising above the axle box 18, as shown in Figure 2. The height h 'is for example substantially between 475 mm and 725 mm. Such a result can be obtained thanks to the primary suspension device 20 according to the invention as will be described later.

When the primary suspension device 20 is not stressed, the spar 16 extends substantially to the same height as the axle box 18 facing it. The primary suspension device 20 extends in the longitudinal direction between a longitudinal end 26 of the spar 16 and the axle box 18 so as to suspendably connect the axle box 18 to the spar 16.

The primary suspension device 20 comprises at least one elastic element 28 extending between a plate 30 integral with the axle box 18 and a bearing surface 32 integral with the spar 16. The bearing surface 32 extends to above and parallel to the plate 30 so as to define between them a space extending in a direction of elevation in which the elastic member 28 extends.

The plate 30 is secured to a lower portion 34 of the axle box 18 and extends longitudinally from it to the longitudinal end 26 of the spar 16. Thus, the plate 30 is offset longitudinally to the inside the bogie 10 relative to the axis of rotation A. The bearing surface 32 extends longitudinally facing the plate 30 from an upper portion 36 of the spar 16, that is to say that the bearing surface 32 is shifted longitudinally towards the axle box 18 relative to the longitudinal end 26 of the spar 16. The elastic element 28 is for example formed by a helical spring whose axis extends in the direction elevation and whose ends bear on the plate 30 on the one hand and on the bearing surface 32 on the other. According to the embodiment shown in Figure 2, the primary suspension device comprises two coaxial coil springs, one of the springs extending inside the other and wound in the opposite direction. The elastic element 28 extending between the plate 30 and the bearing surface 32, this elastic element 28 is also arranged between the axle box 18 and the longitudinal end 26 of the beam 16 in the longitudinal direction.

The primary suspension device further comprises two connecting rods, namely a lower link 38 and an upper connecting rod 40 each joining the longitudinal end 26 of the spar 16 to the axle box 18.

The lower rods 38 and 40 are identical, that is to say they have the same shape and the same length, and extend in parallel in substantially longitudinal directions when the primary suspension device is not requested. . Each connecting rod 38, 40 is hinged on one hand at one of its ends to the axle box 18 and on the other hand at its end to the spar 16 about axes of articulation substantially parallel to the axis of rotation A.

More particularly, the lower link 38 is articulated to the lower portion 34 of the axle box 18 on the one hand and to a lower portion 42 of the spar 16 on the other hand. The lower articulation point 44 between the lower connecting rod 38 and the lower part 34 is shifted longitudinally and in the direction of elevation with respect to the axis of rotation A. Thus, the lower articulation point 44 is shifted towards the tray 30 in the longitudinal direction and is disposed under the axis of rotation A in the direction of elevation, as shown in Figure 2.

The upper link 40 is articulated to an upper portion 46 of the axle box on the one hand and to the upper portion 36 of the spar 16 on the other hand. The upper articulation point 48 between the upper link 40 and the upper part 46 is offset longitudinally and in the direction of elevation relative to the axis of rotation A. Thus, the upper articulation point 48 is shifted towards the outside the bogie in the longitudinal direction and is disposed above the axis of rotation A in the direction of elevation, as shown in Figure 2.

Thus, the lower articulation points 44 and upper 48 are arranged on either side of the axis of rotation A in the longitudinal direction and in the direction of elevation. According to the embodiment shown in FIG. 2, the lower articulation points 44 and upper 48 and the axis of rotation A are aligned along a line inclined with respect to the longitudinal direction and the elevation direction.

The lower and upper links 38 being identical, the lower articulation point 50 between the lower link 38 and the lower part 42 of the spar and the upper articulation point 52 between the upper link 40 and the upper part 36 of the spar are also offset relative to each other in the longitudinal direction and in the direction of elevation.

Thus, the articulation points 44, 48, 50, 52 form a deformable parallelogram according to the movement of the connecting rods induced by the movement of the spar 16 relative to the axle box 18. Such a deformable parallelogram makes it possible to take up the forces applied. between the frame and the rolling part of the bogie according to the elevation direction and resume the torque generated by the cantilevered mounting of the elastic member relative to the axis of rotation A, that is to say the offset mounting in the longitudinal direction of the elastic member 28 relative to the axis of rotation A.

The plate 30, the bearing surface 32 and the elastic element 28 extend between the lower link 38 and the upper link 40 in the elevation direction.

Insofar as the plate 30 extends from the lower part 34 of the axle box 18 and towards the spar 16, it is not necessary, to place the bearing surface opposite the plate, to provide that the beam passes over the axle box 18 as is usually the case. Thus, by comparing the traditional bogie shown in Figure 1 and the bogie according to the invention, a space between 200 mm and 450 mm can be gained above the axle box 18.

Thus, the bulk of the frame 12 in the direction of elevation is reduced, since the height h 'at which the spar 16 extends may be smaller than the height h of the wheel, as has been described above, while retaining an effective primary articulation device 20 able to suspend the frame 12 with respect to the axle box 18.

Such a bogie is particularly suitable for low floor rail vehicles, in which it is desired that the low floor also extends to the right of the bogie without limiting the available volume volume volume. This is for example the case in a two-stage railway vehicle in which the interconnection passage connecting two cars extending above the bogie also comprises two floors.

In such a railway vehicle, the interconnecting passage comprises a lower floor connecting the lower floors of two adjacent cars and an upper floor connecting the upper floors of these two cars, the lower floor passing over the bogie. Since frame members 16 extend at a reduced height, the height of the lower floor of the interconnect passage may also be reduced, thereby increasing the available space in the interconnect passage.

Such a truck can also be used when it extends directly under a car lowered lower floor.

Claims (10)

A railway vehicle bogie (10) comprising a frame (12) comprising at least one spar (16) extending in a longitudinal direction and at least one wheel (14), said wheel (14) being mounted on a box axle (18) and being rotatable relative to said axle box (18) about an axis of rotation (A) substantially perpendicular to the longitudinal direction, said axle box (18) being attached to the axle beam (16) by a primary suspension device (20) comprising an elastic element (28) arranged to allow a clearance in a direction of elevation of the frame (12) relative to the axle box (18) and to the wheel (14), the elevation direction being substantially perpendicular to the longitudinal direction and to the axis of rotation (A), said elastic element (28) extending between a plate (30) integral with the axle box (18) and a bearing surface (32) integral with the frame (12) ), characterized in that the plate (30), the bearing surface (32) and the elastic element (28) are arranged in the longitudinal direction between the axis of rotation (A) and the spar (16). 2. - Bogie according to claim 1, wherein the primary suspension device (20) further comprises a lower link (38) articulated on the one hand at a lower hinge point (50) of the spar (16) and d on the other hand at a lower hinge point (44) of the axle box (18) and an upper link (40) hinged on the one hand to an upper hinge point (52) of the spar (16) and on the other hand at an upper articulation point (48) of the axle box (18), the lower articulation point (50, 44) and the upper articulation point (52, 48) of the spar ( 16), respectively of the axle box (18), extending one below the other in the direction of elevation, the plate (30), the bearing surface (32) and the elastic member (28) being arranged in the elevation direction between the lower link (38) and the upper link (40). 3. Bogie according to claim 2, wherein the lower hinge point (44) and the upper hinge point (48) of the axle box (18) are arranged on either side of the hinge. axis of rotation (A) according to the direction of elevation 4. - Bogie according to claim 2 or 3, wherein the lower hinge point (44) and the upper hinge point (48) of the axle box (18) are arranged on either side of the axis of rotation (A) in the longitudinal direction. 5. Bogie according to any one of claims 2 to 4, wherein the hinge pins of the lower rods (38) and upper (40) to the spar (16) and to the axle box (18) are substantially parallel to the axis of rotation (A). 6. - Bogie according to any one of claims 2 to 5, wherein the lower link (38) and the upper link (40) are of the same length. Bogie according to any one of claims 1 to 6, wherein the bearing surface (32) extends in the longitudinal direction from a longitudinal end (26) of the spar (16) to the box. axle (18), said longitudinal end (26) extending opposite the axle box (18) in the longitudinal direction. 8. Bogie according to any one of claims 1 to 7, wherein the spar (16) extends to a height (h '), measured in the direction of elevation, less than the height (h) of the wheel (14). 9. - Bogie according to any one of claims 1 to 8, wherein the elastic member (28) comprises at least one helical axis spring extending in the direction of elevation. 10. Bogie according to any one of claims 1 to 9, wherein the frame (12) comprises at least two longitudinal members (16) each of the longitudinal ends (16) is fixed to an axle box (18) by a primary articulation device (20), a wheel (14) being rotatably mounted on each of said axle boxes (18), the elastic members (28) of the primary articulation devices (20) each extending between an axle box (18) and a longitudinal end (26) of a spar (16) in the longitudinal direction.