EP0592388B1 - System for regulating the pressure of transverse suspension between bogie and coach body of railwax vehicles - Google Patents

Abstract

System for regulating the pressure level in a transverse suspension between bogie and coach body for railway vehicles, in which the bogie frame is connected to the coach body via at least two pneumatic spring elements, preferably pneumatic spring bellows which are connected to a compressed air source via control valves when the associated spring element experiences spring compression from a blocking basic position or are otherwise connected to the external air, the valves which are associated with the spring elements which act in opposition to one another being coupled in opposite directions and the control valves being capable of being actuated by means of at least one lever, the control valves (6) clearing a relatively small cross-section in a narrow area along both sides of the blocking position and clearing a large valve cross-section in an adjoining wider area on both sides and the blocking position of each valve (6) being achieved with a small spring compression of the associated spring element (4). <IMAGE>

Description

The invention relates to an arrangement for regulating the pressure level in a transverse suspension between bogie and car body for rail vehicles according to the preamble of claim 1.

The transverse suspension of rail vehicles was generally only given by the transverse stiffness of the secondary suspension and a progressive end stop. When driving straight, the transverse stiffness of the secondary suspension offers a very soft spring characteristic. That is why the wheel-rail forces are very small. When cornering, however, the car body is deflected by the centrifugal force so that it is finally pressed against the end stop. The spring characteristic rises steeply in this case, which means that higher accelerations (shocks) can be transmitted to the car body. This also increases the wheel-rail forces and the associated mechanical loads on the vehicles and the rails themselves.

For this reason, transverse suspensions for rail vehicles were created, the spring rate of which is low even at high, free lateral accelerations, so that the inertia can also be used when cornering in order to achieve a soft vibration due to the high mass of the car body and the small spring constant.

In these transverse suspension constructions, such as that of EP-OS 128 126, the bogie frame is connected to the car body via at least two horizontally acting pneumatic spring elements, preferably air suspension bellows, which are connected to a compressed air source or the outside air via closable control valves , wherein the control valves by means of at least one lever connected to the bogie frame when the springs associated spring elements can be actuated and release the connection between the compressed air source and the spring element.

In addition to the spring action of the secondary springs in the transverse direction, a further suspension is thus set in parallel. The air suspension provided has the desired flat characteristic so that small deflections are softly cushioned. However, if the deflections exceed a certain limit, the air pressure is readjusted. This also increases the level of force in the transverse suspension. Since the transverse movements due to compensating disturbances are much smaller than the maximum transverse movements between the bogie and the body due to the centrifugal forces when cornering, these small movements remain uncontrolled due to rail disturbances and are intercepted by the transverse spring with a flat spring characteristic.

The increase in the spring characteristics of air springs at higher operating pressures can be kept small by a sufficient additional volume.

The invention has for its object to provide a simple and reliable arrangement for regulating the pressure level in the spring elements of the cross suspension described above. In doing so, a soft coordination when compensating transverse forces should lead to an increase in comfort, especially with S-curves, while at the same time reducing air consumption.

According to the invention the object is achieved by the characterizing feature of patent claim 1. Within a narrow area around the middle position of the car body in relation to the bogie, both control valves are in a position that connects the spring elements with the outside air, so that the spring characteristics in this area are due to the high mass of the car body and the small spring constant Secondary suspension is given. In the event of a greater deflection caused by static or quasi-static forces, such as the centrifugal force when driving through a curve, the control valve associated with the spring element is first blocked and then a small valve cross section is released for connection to the compressed air source, so that a slow pressure increase in this spring element he follows. After exceeding an even greater transverse deflection between the bogie and the body, the maximum valve cross section is finally released so that the spring element can quickly build up a pressure which counteracts the static or quasi-static force and presses the body back towards the center. This increases the force level of the transverse suspension, but the slope of the characteristic remains essentially unchanged. After the end of the action, for example the centrifugal force, the car body is pushed slightly in the opposite direction of the force acting until the control valve of the spring element under pressure is brought into its open position, which connects the air bellows to the outside air. Then both control valves are again in the venting position and the state before the static or quasi-static force acts is restored. Due to the different released valve cross sections, the pressure is built up slowly and in addition to gaining control time, the slow interception of the transverse force achieves a softer characteristic and increases comfort.

A further advantage results from the measure according to claim 2. While in the middle position of the car body relative to the bogie both control valves are set to venting with a small valve cross-section, when the pressure builds up slowly in one spring element, the opposite spring element with opposite action is quickly vented with a large valve cross-section, so that the pressure build-up and the build-up of a counterforce are opposed to the lowest possible resistance.

The feature of claim 3 allows a precise adjustment of the breather of the spring element. Within a narrow area around the zero position between the car body and the bogie, the two spring elements acting in opposite directions are connected to one another, while they are separated from one another outside this area. When driving straight ahead, the air volume contained in the spring elements is only blown back and forth between the two elements, thus reducing the air consumption. The particularly advantageous effect of the connecting line and the valve provided therein comes into play after the end of a curve or after the end of the action of a static or quasi-static force. If the car body is pressed on the opposite side of the previous deflection, the air of the pressurized spring element is blown into the opposite spring element acting through the opening of the valve in the connecting line, so that this initially without further air consumption moves beyond the zero position intercepts. This is also possible because the venting of both spring elements takes place in this area with a relatively small valve cross section, so that there is sufficient air volume for this purpose. Undesired vibrations of the transverse suspension can be dampened or prevented by installing a throttle in the connecting line.

The feature according to claim 4 results in a precise synchronization of the separation of the two oppositely acting spring elements with the start of ventilation of the loaded spring element to compensate for the transverse force that occurs.

The feature of claim 5 results in a symmetrical arrangement for deflections on both sides of the bogie or the body, so that the same on both sides Conditions for lifting lateral forces are provided. However, should a preferred direction of force occur under special conditions, for example with closed routes with a preferred direction of centrifugal force, it is also possible to take the arrangement into account by moving the area limits, in particular shifting these limits with respect to the zero position between the body and the bogie.

With the control arrangement described in the preceding paragraphs, the required increase in the force level of the respective spring element can be carried out in a simple manner. Malfunction-prone electronic elements can be avoided with this simple mechanical-pneumatic arrangement, whereby a robust and reliable construction is obtained. The control arrangement according to the invention is suitable for both powered bogies and running bogies.

Fig. 1

ein Ausführungsbeispiel für die erfindungsgemäße Anordnung in schematischer Darstellung,

Fig. 2

zeigt ein Schaltschema einer beispielhaften Ventilanordnung,

Fig. 3

zeigt ein Diagramm mit den Kennlinien der drei vorgesehenen Ventile und

Fig. 4

ein Diagramm mit den Kennlinien der Querfederung bei Anwendung der erfindungsgemäßen Druckniveauregelung.

In the following description, the invention will be explained in more detail using an advantageous embodiment and with reference to the drawings. It shows

Fig. 1

an embodiment of the arrangement according to the invention in a schematic representation,

Fig. 2

shows a circuit diagram of an exemplary valve arrangement,

Fig. 3

shows a diagram with the characteristics of the three intended valves and

Fig. 4

a diagram with the characteristics of the transverse suspension when using the pressure level control according to the invention.

In Fig.1, 1 denotes the lower part of the body frame. The car body is usually on two, often several bogies, and the bogie frame is designated by 2. To the transverse movements of the body frame 1 limit with respect to the bogie frame 2, for example, a stop pin 3 is provided in the middle of the bogie, which is firmly connected to the bogie.

The bogie frame 2 is connected to the car body 1 via two horizontally acting pneumatic elements 4. In the embodiment of the invention shown in Fig. 1, said pneumatic elements 4 are air bellows. These bellows 4 give the desired flat spring characteristic for the transverse movements due to rail faults, so that these faults are softly cushioned.

A progressive end stop (not shown), preferably a rubber buffer, is advantageously provided on both sides of the suspension. This dampens excessively large lateral movements of the car body 1 with respect to the bogie 2, as could occur, for example, in the event of a defect in the air suspension or in the case of excessive lateral accelerations. In such a case, the end stop comes into contact with the centrally located stop pin 3 of the bogie 2 and thus the progressive spring characteristic of the stop begins to take effect. The end stop is advantageously arranged inside the pneumatic elements 4, which saves space and is protected against external influences.

As soon as the car body 1 is deflected in the transverse direction with respect to the bogie 2 by a certain freely selectable amount, the supply of compressed air from the compressed air source 7 into the respectively loaded air bellows 4 begins via the control valve 6. The control valves 6 are actuated by means of one lever each 5, whose deflection in one direction releases the connection to the compressed air source 7 and whose deflection in the opposite direction releases a connection of the air bellows 4 to the outside air. The levers 5 of both control valves 6 are with a preferably attached to the stop pin 3 crossbar 8. In a certain area in between, the control valve 6 closes both connecting lines. By increasing the pressure in the respective air bellows 4, the centrifugal acceleration is compensated for, so that minor disturbances in the flat characteristic curve area of the air suspension are absorbed even when cornering.

In order to keep the increase in the stiffness of the air suspension as small as possible when the pressure increases in the event of regulation of larger centrifugal accelerations, it can advantageously be provided that an additional volume is in pneumatic connection with the air suspension bellows 4. If this additional volume is of sufficient size, the increase in stiffness can be kept insignificant even when the level of the spring characteristic is increased by increasing the air pressure in one of the air bellows.

A circuit diagram of an exemplary practical valve arrangement for the arrangement according to the invention is shown in FIG. 2. From the compressed air source, not shown here, air under high pressure passes via a through tap 10 and an overflow valve 11 to the two control valves 6. These either connect the air bellows 4 to the outside air via an overflow valve 14 each, or supply compressed air to the latter. Advantageously, there is also a pressure reducing valve 12 and, associated with each control valve 6, one check valve 13 each. Compressed air is continuously supplied to the air springs 4 at low pressure via the two latter valves 12 and 13, so that they cannot collapse.

As indicated by the broken lines in FIG. 2, the control valves 6 and the valve 9 are mechanically actuated to connect the two air bellows to one another.

The characteristic curves of the three valves 6, 9 are shown in FIG. 3, the valve cross section being plotted over the transverse path. The valve 9 connecting the spring elements 4 is characterized by the characteristic shown in broken lines, while the solid or the dotted characteristic are assigned to the two control valves 6. For these it is true that the branch originating from the abscissa and pointing away from the origin corresponds to the characteristic curve of a connection with the compressed air source, that is to say a venting of the respective spring element 4 with air under high pressure, while the branch directed towards the origin corresponds to a venting of the respective one Spring element corresponds.

The effect of the arrangement according to the invention will now be explained with special reference to FIGS. 3 and 4, the latter showing the characteristic curve for a transverse suspension with the control arrangement according to the invention.

With relatively small deflections of the car body 1 with respect to the bogie 2, both control valves are in a position in which the two air spring elements 4 are connected to one another via the valve 9 and, moreover, both elements 4 are vented via the control valves 6 with a very small cross section. The spring characteristic is thus characterized by the curve shape A, which reflects the transverse stiffness of a conventional secondary suspension, for example a flexicoil spring or a purely unregulated air suspension. If a progressive end stop, for example a rubber buffer, is provided, the progressive characteristic curve represented by curve B results with larger transverse deflections without the control behavior according to the invention.

Exceed the transverse deflections of the car body 1 with respect to the bogie 2, however, the limits marked by S₁, within which the two air spring elements 4 are connected, the two elements 4 separated by shutting off the valve 9 and at the same time slow ventilation of the loaded spring element 4 begins over a small cross section of the associated control valve 6. At the same time, the valve cross section of the control valve 6 associated with the counteracting spring element 4 is enlarged and this element 4 over a large cross section heavily vented. This state remains until a second limit S₂ is reached for the transverse deflection, so that between the transverse deflections S₁ and S₂ there is a flat characteristic curve of the transverse suspension.

However, if the transverse path exceeds the limit S₂ in the deflection of the car body 1 with respect to the bogie, the compressed spring element 4 is now ventilated over a large cross section of its associated control valve 6, while the spring element acting in the opposite direction remains strongly vented. So that the pressure in the loaded spring element 4 is increased until the car body 1 has moved so far towards the center that the limit S₂ for the transverse path of the deflection is undershot. Superimposed smaller deflections are not corrected by the arrangement according to the invention, which is why a flat characteristic curve corresponding to a parallel shifted spring characteristic curve A comes into play for this, and minor faults in the shaded area within the zone lying between the two limits S 1 and S 2 are soft from the secondary suspension, however according to the increased level of force.

Since an end stop is also provided in the construction according to the invention, the spring characteristic curve, starting from the highest possible level of force, after exceeding the spring range of the air suspension, outside the limit S₂ for the transverse travel, the progressive curve shape B '.

After completion of the condition causing the large deflection of the car body, the deflection quickly decreases due to the pressure of the strongly ventilated spring element 4 and the transverse travel finally falls below the limit S 1, so that the pressurized spring element 4 is no longer supplied with compressed air while the valve 9 in turn releases the connecting line between the two spring elements 4 acting in opposition to one another. The spring element 4 under pressure is thereby vented to the environment on the one hand with a small cross-section, but the largest proportion of the compressed air is conducted via the connecting line into the spring element 4 acting in the opposite direction. Since this is also vented only with a small cross-section, a pressure builds up in it, which softly intercepts a movement that overshoots the zero position of the car body 1 relative to the bogie 2 and keeps the transverse path within the limits S 1 on both sides of the zero position.

The arrangement according to the invention is particularly advantageous if an oppositely directed force acts immediately after the end of the action of a static or quasi-static force in one direction. In conventional arrangements, this would lead to an overshoot of the deflection by superimposing the static or quasi-static force and the force exerted by the spring element under pressure. As a result, the progressive end stop could be reached quickly and a hard transverse spring characteristic with transmission of shocks into the car body could be achieved.

In the arrangement according to the invention, however, the corresponding movement of the car body is intercepted by the air volume transmitted from a spring element 4 to the spring element 4 acting in the opposite manner and, in the event of an additional deflection, the control valve 6 associated with the now compressed spring element 4 is blocked, the Pressure in this spring element 4 is already at a much higher level than the normal level, for example while driving straight ahead. Any further necessary build-up of a counterforce in the spring element 4 by vigorous ventilation with compressed air can now proceed much more quickly, so that the deflection due to the static or quasi-static force is stopped long before the progressive end stop is reached. This means that smaller deflections can be smoothly cushioned at all times, even on routes with rapidly successive curves, and that hard impacts are never transmitted to the interior of the car. This increase in driving comfort, which also puts less strain on rails and wheelsets, is achieved at the same time with reduced air consumption, since when the deflection changes from one direction to the other the air volume of the spring element under pressure is not blown off, but is directed to the spring element acting in the opposite direction .

Claims (5)

1. An arrangement for controlling the pressure level of a transverse suspension between the bogie and the waggon body of rail vehicles, wherein the bogie frame (2) is connected to the waggon body (1) via at least two opposite, pneumatic and oppositely acting transverse spring elements (4), preferably pneumatic spring bellows; at least with a strong inward stroke (of the suspension) the transverse spring elements (4) are connected via control valves (6) to a compressed air source (7), while with a slight inward stroke said elements are isolated and in the unloaded state and with an outward stroke they are connected to atmosphere; and the control valve (6) associated with oppositely acting spring elements are coupled to opposite hands and can each be actuated by means of at least one lever (5) when the waggon body (1) is deflected in relation to the bogie frame (2), the neutral locking position of each valve (6) being reached with a slight inward stroke of the associated transverse spring element (4), characterised in that on both sides the control valves (6) have around the neutral position two further control stages, the second stage opening up a relatively small cross-section and being provided in a narrow zone around the neutral position, the third stage opening up a large valve cross-section and being provided outside the narrow zone of the second stage.
2. An arrangement according to Claim 1, characterised in that the neutral position of a control valve (6) associated with one transverse spring element (4) substantially coincides with the transition between the second and third control stage of the control valve (6) associated with the oppositely acting transverse spring element (4).
3. An arrangement according to Claims 1 or 2, characterised in that the two oppositely acting spring elements (4) are connected to one another via a line in which at least one valve (9) is provided having two control stages, its first control stage opening up a precisely defined cross-section of the line in a narrow zone around the neutral position and its second control stage locking the line on both sides outside said zone, while the neutral position of the valve (9) is reached when the waggon body (1) is in a central position in relation to the bogie frame (2).
4. An arrangement according to Claim 3, characterised in that the transition from the first to the second control stage of the valve (9) substantially corresponds in each case to the neutral position of the control valves (6).
5. An arrangement according to one of Claims 1 to 4, characterised in that when the waggon body (1) is in a deflection-free central position in relation to the bogie frame (2), the control valves (6) are moved the same distance out of the neutral position, and the or each valve (9) takes up the neutral position in the line (18).

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