EP0035443B1 - Chassis suspension on at least two axles of a railway vehicle, and chassis provided with this suspension - Google Patents

Abstract

1. Suspension for railway vehicle underframe having two axles, at least one of the axles being mounted, in the vinicity of each of its ends, in an axle box (7), this suspension (6) comprising, for each box (7) of this axle (4), elastic means (9) supported by the axle box and which, on each side of this latter, are applied against the underframe through the intermediary of at least one connecting link pivoted with respect to the underframe (1) and with respect to that end of the elastic means (9) which is associated with the underframe, the two lines (XX', YY') of application of the forces to which these links (13, 14) are subjected and which pass through the pivot points (16, 17, 21) of these latter having opposite inclinations (A, B), one of the links (14) being mounted in tension, and coupling means arranged between the axle box (7) and the pivots (16) connecting the links (13, 14) to the elastic means (9) so that any displacement of the axle box in a longitudinal direction of the underframe (1) produces a corresponding displacement of these pivots (16), characterized in that the upper link (13) is mounted in compression, that the two links (13, 14) have different inclinations (A, B), and that the underframe carries a reference face (31) against which the axle box (7) is applied in a straight line under the action of the threshold of force exerted on it by reason of the difference in inclination of the links (13, 14).

Description

The present invention relates to a suspension for a chassis with at least two axles of a railway vehicle, such as a wagon.

The term “suspension” in the present description means the partly deformable mechanical means which connect the axles to the chassis, the latter possibly being as well that of a wagon with at least two axles as that of a bogie articulated to the frame of a wagon with several bogies.

The present invention also relates to a chassis provided with this suspension.

In the particular case of wagons with two axles, each axle, mounted at each of its ends in an axle box, is held perpendicular to the axis of the chassis by spring systems provided with damping means which each connect a axle box to chassis.

In the particular case of bogie wagons with at least two axles, the assembly is similar. According to a particular embodiment described in FR-E-82179, each axle box supports the chassis by means of at least two helical compression springs mounted on either side of the axle. A spring is compressed between the axle box and a bonnet on which part of the wagon's weight is exerted. For each axle box, the axle chassis, while the bonnet is biased obliquely downwards via an articulated member connected to the chassis. The axle box is frictionally mounted between a flat reference face of the chassis and a pusher actuated by the bonnet which tends to apply the axle box against the reference face due to the obliquity of the stress due to the articulated organ.

This assembly simultaneously ensures the damping of the oscillations of the springs and the rigorous positioning of the axle perpendicular to the axis of the chassis.

These suspensions work satisfactorily on straight rail lines. On the other hand, when the chassis moves on a curved section of track, the simultaneous maintenance of the two axles in a position perpendicular to the axis of the chassis causes significant friction between the wheels and the railway track. This significant friction between the wheels and the track. This friction leads to premature wear of the wheels, in particular of the stepped - or flanged - part of the latter, and curved sections of railway track. In addition, the bogies thus equipped hardly fit into the raised curves, and we even note the derailment of certain wagons in tight curves.

FR-A-1 072 207 describes a suspension which conforms to the preamble of claim 1 and which remedies the drawbacks stated above. According to this document, the two flanges are traction flanges which are arranged symmetrically when the vehicle is traveling in a straight line, the axle box then having an average position between two longitudinal travel limits. This arrangement has two drawbacks. Indeed, the straight line position does have a certain stability because as the axle deviates from it on one side or the other, there appears an increasing return effort, but this stability is not exemplary and we can see some yaw effects in a straight line. On the other hand, the increasing return force considerably hinders the axle when it has to take strong orientations in tight curves.

The object of the present invention is to remedy these drawbacks by proposing a suspension in which the axles have a more stable straight line position while negotiating tight curves more easily.

This object is achieved by using the means set out in the characterizing part of claim 1.

The difference in inclination between the flanges is the cause of a restoring force urging the axle box against the reference face.

Thus, in a straight line, the axle is in a position well determined by the reference face. To remove it, it is no longer enough for a small disturbance, it takes an effort exceeding the effort threshold determined by the difference in inclination between the flanges. The axle is therefore very stable in a straight line. When cornering, such an effort exceeding the aforementioned threshold appears. However, the combination of the traction flange and the compression flange means that the initial difference in inclination between the flanges is kept appreciably when the axle box deviates from the reference face.

This difference in inclination is thus at the origin of a restoring force which, instead of increasing, varies little as a function of the spacing of the axle box relative to the position where it is in abutment against the face. reference. The axle, once it has overcome the restoring effort, therefore has no difficulty in orienting itself, even in a tight curve.

Preferably, the elastic means comprise at least two springs mounted on either side of the axle, at least one spring on each side of the axle is located between the box and a cap connected to the chassis by the connection flanges .

According to another object of the invention, the two-axle chassis provided with a suspension of the above kind is characterized in that this suspension equips the two axles of the chassis, the articulated flanges mounted in traction and in compression occupying in the two axles in substantially symmetrical positions relative to the transverse median plane of the chassis.

Thus, the two axles of the chassis can be oriented relative to the chassis as a function of the curvature of the track, which limits the angular deviations of the axles relative to the chassis; in addition, the chassis behavior is sensitive identical depending on whether the wagon travels in one direction or the other on the railway, which is particularly interesting in the case of railway equipment.

Other features and advantages of the invention will emerge from the description below.

• la figure 1 est une vue en élévation latérale d'un bogie dont les deux essieux sont équipés de la suspension conforme à l'invention ;
• la figure 2 est une demi-vue de face du bogie de la figure 1 ;
• la figure 3 est une vue de dessus avec arrachement, du bogie de la figure 1 ;
• la figure 4 est une vue schématique, à échelle agrandie, avec coupe partielle, de l'une des suspensions du châssis de la figure 1 ;
• la figure 5 est une vue analogue à la figure 4, mais plus schématique, et montrant en trait mixte la position prise par les diverses pièces en cas de déplacement latéral de la boîte d'essieu par rapport au châssis.

In the appended drawings, given by way of nonlimiting examples:

• Figure 1 is a side elevational view of a bogie whose two axles are equipped with the suspension according to the invention;
• Figure 2 is a half front view of the bogie of Figure 1;
• Figure 3 is a top view with cutaway, of the bogie of Figure 1;
• Figure 4 is a schematic view, on an enlarged scale, with partial section, of one of the suspensions of the chassis of Figure 1;
• Figure 5 is a view similar to Figure 4, but more schematic, and showing in phantom the position taken by the various parts in the event of lateral movement of the axle box relative to the chassis.

The bogie shown in FIGS. 1 to 3 comprises a chassis which comprises two longitudinal members 1 connected by a central cross member 32 and two end cross members 2 constituting with the longitudinal members 1 a frame carried by four wheels 3 coupled in pairs by means of two axles 4. Each axle 4 is connected at its two ends to the chassis by means of a suspension 6 situated beyond the corresponding wheel 3 relative to the middle of this axle 4.

As shown in particular in Figure 4, each axle 4 is carried at its two ends by an axle box 7 in which are housed the ball bearings which allow the rotation of the axle 4 relative to the chassis.

The axle box 7 has two bases 8 directed on either side of the axle 4 at a distance below the beam 1, and on each of which rests the lower end of a helical suspension spring 9.

The springs 9 are compressed between these two bases 8 and two caps 11, 12 connected to the chassis and on which is exerted, in service, part of the weight of the wagon.

According to the invention, each of the caps 11, 12 is connected to the spar 1 by a pair of connecting flanges 13 or 14. The two flanges 13 or 14 of the same pair are mounted in parallel and articulated to the cap 11 or 12 corresponding which, for this purpose, carries laterally two opposite pins 16 with an axis substantially parallel to the axle 4.

The flanges 13 constitute connecting rods mounted in compression between the cap 11 and the chassis 1. From the pin 16, the flanges 13 are directed opposite the base 8 and are fixed on an axis 17 which is articulated on the side member 1.

The flanges 14 are rings mounted in traction between the cap 12 and two ears 18 integral with the spar 1. These ears 18 are formed at the end of a wing 19 with a U-shaped section starting from the spar 1, directed towards the base 8; they extend the legs of the U, which are turned towards the spring 9, and thus come from either side of the latter. Each flange 14 is articulated to the ear 18 by means of a pin 21, carried by this ear 18, directed towards the outside of the wing 19 in a U, with an axis substantially parallel to the axle 4, and more close to the base 8 that the pin 16 of the cap 12. In the example shown the distance between the pins 16 of the cap 11 of the axis 17 is greater than the distance between the pins 16 of the cap 12 of the pins 21 .

As shown in Figure 4, the line XX 'which joins the axis 17 and the pin 16 of one or other of the flanges 13 and the line YY' which joins the pins 16 and 21 of the flange 14 which faces are inclined in opposite directions to each other with respect to the axis ZZ 'of the springs 9 which is substantially vertical when the bogie is in the service position on a horizontal railway track, and converge downwards, at below the axle box 7. In addition, the angle of inclination B of the line YY 'is greater than the angle of inclination A of the line XX' relative to the axes ZZ 'in the example shown. However, it is conceivable to swap the position of the ring 14 and the link 13 relative to the median axis of the axle box. In this case, the angle A of the link must be greater than the angle B of the ring.

The inclination of the lines XX 'and YY' which substantially constitute the lines of application of the forces on the caps 11 and 12, determines a stress on the latter towards each other and towards the axle box 7.

Under the effect of this stress, the caps 11 and 12 are supported on either side of the axle box 7 by means of two opposing pushers 23. The pushers 23 include a tail 24 whose end rests against the caps 11, 12, and which is mounted to slide in a bore 26 formed in the base of the U of the wing 19 for one of the pushers 23, and, for the other pushbutton 23, in a wing 22 integral with the spar 1 and facing the base of the U of the wing 19 on the other side of the axle box 7.

The pushers 23 also include a head 27 whose front face, which is flat, bears on the flat lateral faces also of the axle box 7. Friction linings 28, 29, for example made of manganese steel, are welded to the front faces of the heads 27 of the pushers 23 as well as to the flat side faces of the axle box 7.

The pushers 23 cannot sink into the bores 26 beyond a fully retracted position in which the rear face of their head 27 is in abutment against a boss 31 which opens each of the bores 26 on the side of the box. axle 7.

The bogie shown in Figure 1 has at the two ends of each of its axles 4 a suspension of the kind just described. The mounting of these suspensions is symmetrical by relative to the transverse median plane of the bogie, so that for each suspension, the flanges 13 which work in compression are associated with the spring 9 situated opposite the other axle 4 relative to the axle box 7 considered and have a less inclination than the flanges 14 which work in traction.

• Les efforts qui s'exercent sur les chapeaux 11, 12 désignés par R1 et R2 à la figure 4 ont une composante P1 ou P2 dirigée selon ZZ', et une composante F1 ou F2 dirigée selon l'axe des poussoirs. Les composantes P1 et P2 qui tendent à comprimer les ressorts 9 sont sensiblement égales, tandis que, du fait de la différence d'inclinaison des lignes XX' et YY', la composante F1 appliquée au chapeau 11 est inférieure à la composante F2 appliquée au chapeau 12.

The operation of the suspension described above is as follows:

• The forces exerted on the caps 11, 12 designated by R1 and R2 in FIG. 4 have a component P1 or P2 directed along ZZ ', and a component F1 or F2 directed along the axis of the pushers. The components P1 and P2 which tend to compress the springs 9 are substantially equal, while, due to the difference in inclination of the lines XX 'and YY', the component F1 applied to the cap 11 is less than the component F2 applied to the hat 12.

When the bogie travels in a straight line, this difference between F1 and F2 pushes the axle box 7 towards the cap 11, so that the pusher 23 assigned to this cap 11 is in its retracted position with its head 27 in abutment on the boss 31. This arrangement ensures a stable balance of the two axles during the straight line movement of the wagon.

In this position, the axes of the pushers 23 are located in the same plane as the axes of the pins 16 of the caps 11,12. Furthermore, the distance D (FIG. 5) remaining between the rear face of the head 27 of the pusher 23 associated with the cap 12 and the corresponding boss 31 determines the maximum lateral stroke of the axle box 7, relative to the chassis. In the case of a bogie, the distance D can be, for example, 12 mm.

Due to the symmetry of the suspensions of the bogie with respect to the median plane of the latter, on each side of the bogie the wheels 3 are separated at most from each other.

Furthermore, when the wheels 3 encounter unevenness on the railway track, the axle box 7 takes oscillations relative to the chassis which are damped by the friction of the linings 28 of the pushers 23 on the linings 29 of the axle box 7.

When the bogie approaches a curve, the flange of the wheel 3 which is external to the curve and which belongs to the axle 4 arriving at the head bears against the rail and tends to lay flat against the latter.

This effect exerts on the axle 4 a torque which tends to press more the axle box 7 outside the curve against the pusher 23 which is already in the retracted position, and tends to bring the other axle box 7 towards hat 12.

If the force exerted by this torque on the axle box 7 inside the curve is greater than the difference of the forces F1 and F2, this displacement of the axle box 7 takes place and it occupies by example the position shown in phantom in Figure 5.

In this position, the displacement of the axle box 7 has resulted in a corresponding displacement of the caps 11, 12 so that no lateral deformation of the springs 9 is to be feared.

The flanges 13 and 14 have pivoted around the axis 17 and the pins 21 so that the cap 11 is also slightly raised towards the beam 1 while the cap 12 has, on the contrary, slightly approached the base 8.

During this movement of the axle box 7, the inclinations of the lines XX 'and YY' both increase, so that the difference between the components F1 and F2 does not vary substantially and can even be kept substantially constant .

This property constitutes one of the important advantages of the suspension in accordance with the invention because it allows the axles to fit into tight curves without it being necessary to exaggerate the force applied to the boxes 7 by the wheels 3.

As soon as the second axle 4 approaches the curve of the railroad track, the flange of its wheel 3 outside the curve bears on the rail and also tends to move the axle box 7 inside the curve towards the cap 12.

Thus, the two wheels 3 inside the curve tend to approach each other while the other two wheels 3 keep a spacing substantially unchanged.

The suspension according to the invention thus makes it possible to simultaneously ensure the damping of the oscillations and the orientation of the axle 4 with a very small number of parts.

The invention also achieves an excellent compromise between a rigorous positioning of the axles 4 in a straight line and an orientation of the axles 4 in a curve resulting from relatively moderate forces.

Of course, the invention is not limited to the examples described and numerous modifications can be made to these examples.

Thus, the flanges working in traction could be associated with the spring opposite to the other axle of the chassis relative to the axle box considered, and be less inclined than the flanges working in compression.

Furthermore, one can be satisfied with equipping only one axle with the suspension according to the invention.

Claims (7)

1. Suspension for railway vehicle underframe having two axles, at least one of the axles being mounted, in the vicinity of each of its ends, in an axlebox (7), this suspension (6) comprising, for each box (7) of this axle (4), elastic means (9) supported by the axlebox and which, on each side of this latter, are applied against the underframe through the intermediary of at least one connecting link pivoted with respect to the underframe (1) and with respect to that end of the elastic means (9) which is associated with the underframe, the two lines (XX', YY') of application of the forces to which these links (13,14) are subjected and which pass through the pivot points (16, 17, 21) of these latter having opposite inclinations (A, B), one of the links (14) being mounted in tension, and coupling means arranged between the axlebox (7) and the pivots (16) connecting the links (13, 14) to the elastic means (9) so that any displacement of the axlebox in a longitudinal direction of the underframe (1) produces a corresponding displacement of these pivots (16), characterized in that the upper link (13) is mounted in compression, that the two links (13, 14) have different inclinations (A, B), and that the underframe carries a reference face (31) against which the axlebox (7) is applied in a straight line under the action of the threshold of force exerted on it by reason of the difference in inclination of the links (13, 14).

2. Suspension in accordance with claim 1, characterized in that the two lines (XX', YY') of action of the forces to which the links (13,14) are subjected converge downwardly, and that the coupling means comprise two opposing friction push-rods (23) interposed between the axlebox and the pivot (16) connecting the links (13, 14) to the elastic means (9).

3. Suspension in accordance with either claim 1 or claim 2, characterized in that the elastic means comprise at least two springs (9) mounted on each side of the axle (4), at least one spring on each side of the axle being located between the box (7) and a cap (11 or 12) connected to the underframe (1) by the connecting links (13, 14).

4. Suspension in accordance with any one of claims 1 to 3, characterized in that the coupling means (23) associated with the pivot link (13) in compression are intended to exert on the axlebox (7) a lateral force (F1) which is lower than the force (F2) exerted by the coupling means (23) associated with the pivot link (14) in tension.

5. Suspension in accordance with any one of claims 1 to 4, in which the coupling means are push-rods (23), characterized in that, in a position of equilibrium in a straight line, the push-rod (23) which is intended to exert the weakest lateral force (F1) on the axlebox (7) is fully retracted and bears against the reference face (31).

6. Suspension in accordance with claim 5, characterized in that the fully retracted push-rod (23) in a position of equilibrium in a straight line is located opposite the other axle (4) relative to the axlebox (7).

7. Underframe having two axles provided with a suspension in accordance with any one of claims 1 to 6, characterized in that this suspension (6) is fitted to the two axles (4) of the underframe, the pivot links (13, 14) mounted in tension and in compression occupying, in both axles (4), positions substantially symmetrical relative to the transverse median plane of the underframe.

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