EP0592387A1 - System for regulating the transverse suspension between bogie and coach body of railway vehicles - Google Patents

Abstract

System for regulating a transverse suspension between bogie and coach body of a railway vehicle, comprising at least two spring elements which act in the transverse direction, are based on fluid pressure and are provided with controllable valves for adjusting the pressure of their operating medium, by means of a displacement measuring system (8, 8') for the deflection in the transverse direction between bogie (2) and coach body (1), which displacement measuring system (8, 8') is connected to a control unit (12) which actuates at least the control valve (5, 5', 6, 6') associated with the compressed spring element (3, 3', 4, 4') in accordance with a predetermined function for each value, detected by the displacement measuring system (8), of the deflection of the coach body (1) with respect to the bogie (2). <IMAGE>

Description

The invention relates to an arrangement for controlling a transverse suspension between the bogie and the body of a rail vehicle 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 lateral stiffness of the secondary suspension offers a very soft spring line. Therefore, the wheel-rail forces due to rail disturbances 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 small even with high, free lateral acceleration, so that the inertia can also be exploited when cornering in order to achieve low-frequency vibration due to the high mass of the car body and the small spring constant.

For example, EP-OS 128 126 describes a construction in which the bogie frame is connected to the car body via two horizontally acting, adjustable spring elements. If the deflection between the car body and the bogie frame exceeds a certain limit, the previously open connection of the compressed air spring to the environment is completed and with further deflection, the compressed air spring is closed with a Compressed air source connected. As a result, the pressure in the spring element is raised until the resulting force has returned the body to the center position. Small deflections due to rail faults remain unregulated and are absorbed by the transverse suspension with a flat spring characteristic, so that the characteristic frequency of the transverse suspension remains constant even when cornering.

Since the times in the suspension for building up the forces compensating for the lateral acceleration are very short, the air pressure is adjusted relatively quickly and hard. In addition, the return to the central position results in a relatively high air consumption, so that the system has to be more complex. The latter advantage becomes even clearer if, according to the known construction, the characteristic curve is to be made flatter by an additional volume connected to the spring elements in order to increase the comfort, since this volume also has to be filled with air under pressure and this after termination the regulation of transverse forces is blown off.

The object of the present invention was therefore to create an arrangement for regulating a transverse suspension, which controls lateral forces more gently and thus significantly increases comfort, while at the same time significantly reducing air consumption. Small transverse movements due to rail faults should be intercepted with a flat spring characteristic and the characteristic frequency of straight-ahead travel.

According to the invention, this object is achieved by an arrangement according to the characterizing part of patent claim 1.

According to the invention, the relative movement of the car body to the bogie in the transverse direction is taken as the control input. This value is measured with a displacement transducer and to the Control forwarded. This now specifies the target value for the force to be introduced and thus the target pressure in accordance with a predetermined function. This pressure is now regulated in the spring elements by appropriate control of the valves. The pressure control described, however, only affects transverse movements due to static or quasi-static forces, such as are given, for example, by centrifugal force when cornering. Since the transverse movements due to disturbances to be compensated for are considerably smaller than the maximum transverse movements between the bogie and the body due to the static or quasi-static forces, these small movements are not controlled due to rail disturbances and are intercepted by the transverse suspension with the flat characteristic of the secondary spring stage. A low rigidity of the transverse suspension is thus realized for these deflections, so that a soft vibration and thus a high level of comfort can be achieved. The dependency of the target pressure in the spring elements on the deflection determined by the displacement measuring system causes the car body to remain deflected relative to the bogie and its deflection movement is only braked and finally stopped by the pressure increase. Since there is no return to the center guide, the pressure only has to be increased to the extent necessary to compensate for the transverse force, so that this alone results in a lower air consumption when entering a curve compared to the conventional arrangements. In addition, the arrangement according to the invention thus reacts much more softly to transverse deflections of the car body when passing through curves, which represents an additional increase in comfort.

The position measuring system can be based on a mechanical basis, for example using a lever system to proportionally reduce the relatively large transverse movements between the car body and the bogie and to feed it to a compact control unit. This control unit can also be a mechanical system, for example a control disc with a corresponding one control slots or control cams shaped according to the specified function. From this control disc, a further lever arrangement can lead to the control valves for the spring elements and operate them in accordance with the function implemented on the control disc.

Another feature of the invention is characterized in claim 2. By selecting the characteristic of the spring in question, a specification of the target pressure as a function of the deflection of the body relative to the bogie is possible within a wide range, with a simple mechanical-pneumatic structure which is robust and reliable in operation performs the desired regulation of the transverse suspension.

The measure according to claim 3 prevents pressure equalization in the event of short-term and small pressure differences, so that small and short-term deflections due to rail faults or the like can be absorbed by the spring elements without regulating the pressure. It also dampens unwanted vibrations.

The feature according to claim 4 offers a further advantage. The electrical position measuring system is significantly more precise than mechanical arrangements which have play in each joint arrangement. An electronic control unit with a program which effects the pressure regulation in the spring elements described above is much lighter and more compact than a mechanical arrangement and is therefore also ideally suited for retrofitting existing vehicles, for example. The control characteristic can be changed by simple changes to the program or by exchanging the component containing the program and adapted to the respective needs. Finally, the repair and maintenance work due to the modular structure of the electronic circuits can be carried out significantly more easily and with less effort than with mechanical variants. The susceptibility to failure is also in use modern components are at least as small as with proven mechanical designs, usually even less.

The feature of claim 5 causes that from a predetermined limit value for the deflection, the pressure in the spring elements is slowly readjusted, i. H. that the target pressure is a function of time. This also increases or decreases the level of force in the transverse suspension. The transverse movements due to disturbances to be compensated are not controlled, for example, when driving straight ahead on a level route, but are intercepted, for example, when driving through curves by the transverse suspension with the flat characteristic of the secondary spring stage, but at an increased level of force corresponding to the transverse deflection of the car body compared to the bogie. A low level of rigidity is thus realized for these faults with each deflection, and the comfort is significantly increased. In addition, control time is gained again by slowly adjusting the target pressure, so that the arrangement according to the invention reacts much more smoothly to transverse deflections of the car body, which represents an additional increase in comfort.

A significantly flatter characteristic for the transverse suspension can be achieved, in a manner known per se, by a correspondingly large additional volume for the pressure fluid, according to the feature of claim 6. This only compensates for the centrifugal force, for example when cornering, while the small movements due to the rail disturbances are intercepted with a much flatter spring characteristic than with conventional arrangements, whereby the air consumption is also significantly lower, since only these small movements due to small changes in air pressure must be compensated for and no additional volume must be maintained under high pressure in order to guarantee an acceptably flat characteristic curve despite the pressure increase.

An almost horizontal spring characteristic can be realized by the feature according to claim 7, the lowest possible spring stiffness and thus the optimal interception of the small movements caused by rail disturbances being possible.

The feature according to claim 8, however, makes it possible to further minimize air consumption or to ensure an emergency function in the event of a lack of air, so that the setpoint pressure is not completely regulated. This reduction in the control gain of the pressure regulator means that less or almost no air is consumed during cornering. For smaller, faster movements, the cylinders work like an air spring with closed air volume. This does not offer full comfort since the stiffness of the air cylinders is now added to the flat secondary spring, but the body of the car is still not in contact with the stop buffer to limit the lateral deflection relative to the bogie.

A device-like simple construction of the arrangement results from the measure according to claim 9.

A particularly robust, simple control technology and safe construction is possible by the feature of claim 10.

Hiebei forms the feature of claim 11, a preferred construction.

Alternatively, the construction according to claim 12 can be provided.

Due to the feature of claim 13, the two control loops are completely separated from one another and better adapted to the conditions that occur in them. Even if one pump fails, the control function of the other circuit is not impaired, so that the desired function can be maintained at least on one side.

The measure according to claim 14 results in proven and cheap components which are simple and safe to operate and maintain.

This also applies to the alternative measure according to claim 15.

The measure according to claim 16 has the advantage over the two first-mentioned valve types that the valves are faster and react more sensitively to the control influences.

In the hydraulic variant of the arrangement according to the invention according to claim 17, it is advantageously possible that it can also take over the transverse damping with a slight change in the software. The force corresponding to a damper characteristic curve and the transverse force to be introduced to compensate, for example, the centrifugal force during cornering is thus added and specified as a setpoint for the pressure in the spring element.

Fig. 1

ein Einbauschema einer pneumatischen Variante anhand eines Schnittes durch die Drehgestellmitte, wobei eine mechanische Steuereinrichtung unter Verwendung von Pneumatikzylindern vorgesehen ist,

Fig. 2

ein Einbauschema einer pneumatischen und

Fig. 3

ein Einbauschema einer hydraulischen Variante mit elektronischer Steuerung anhand eines Schnittes durch die Drehgestellmitte,

Fig. 4

zeigt ein Diagramm des Kraftsollwertes (Solldruck) über dem Querweg,

Fig. 5

ein Querfederdiagramm (Querkraft über Querweg),

Fig. 6

zeigt schematisch den Regelkreis für die pneumatische Variante und

Fig. 7

den Regelkreis für die hydraulische Variante.

The invention is explained in more detail below with the aid of schematically illustrated exemplary embodiments. It shows

Fig. 1

an installation diagram of a pneumatic variant on the basis of a section through the center of the bogie, a mechanical control device using pneumatic cylinders being provided,

Fig. 2

an installation diagram of a pneumatic and

Fig. 3

an installation diagram of a hydraulic variant with electronic control based on a cut through the center of the bogie,

Fig. 4

shows a diagram of the force setpoint (setpoint pressure) over the transverse travel,

Fig. 5

a transverse spring diagram (lateral force over transverse travel),

Fig. 6

shows schematically the control circuit for the pneumatic variant and

Fig. 7

the control loop for the hydraulic variant.

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. The term bogie means both powered bogies and barrel bogies. In order to limit the transverse movements of the body frame 1 relative to the bogie frame 2, a stop pin 3 is provided in the middle of the bogie, for example, 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 relation to the bogie 2 by a certain freely selectable dimension in the transverse direction, 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 activated by at least one each Lever 61, the deflection in one direction of the connection to the compressed air source 7 and the deflection in the opposite direction releases a connection of the air bellows 4 to the outside air. In a certain area in between, the control valve 6 closes both connecting lines. Since only one-sided loading of the construction takes place when cornering, only the corresponding air bellows is regulated. The increase in pressure in the respective air bellows 4 compensates for the centrifugal acceleration, so that even when cornering, minor disturbances in the flat characteristic curve area of the air suspension are absorbed.

A particularly simple and robust system for pressure level control is now shown in FIG. 1. A pneumatic cylinder 8 is inserted between said lever 61. On the other hand, constructions would also be conceivable in which the lever for actuating the control valve itself is designed as a pneumatic cylinder. Depending on the design requirements, different lever arrangements are also possible, but always with the inclusion of a pneumatic cylinder. A lever 61 extends from the control valve 6 and is connected at right angles to said pneumatic cylinder 8. Depending on the available space or other design requirements, other lever connections can also be provided, or even the pneumatic cylinder 8 can directly, i. H. Actuate the control valve 6 without the interposition of another lever, for example 61.

While the pneumatic cylinder 8 is connected at one end to the control valve 6 or a lever 61 actuating it is, the other end of this cylinder 8 is attached to the bogie frame 2, preferably on the stop pin 3. For the sake of simplicity, the function is only described if the suspension is extended to one side. However, both sides work analogously. When the bogie frame 2 and the stop pin 3 connected to it are deflected to the left in the direction of the arrow s, the left spring element 4 is compressed. As a result, the right pneumatic cylinder is also moved in the direction of the arrow s, and this deflection opens the right control valve 6 for supplying compressed air to the left spring element 4. The piston 81 of the pneumatic cylinder 8 is displaceable against the action of a spring 82, and the active volume 83 of the cylinder 8 is pneumatically connected to said left spring element 4. Therefore, a balance can be established between the air pressure in the spring element 4 and the action of the spring 82, whereby the piston 81 is displaced against the action of the spring 82 while increasing the volume 83. The corresponding control valve 6 is also closed again by this displacement of the piston 81. With a coordinated design of the piston surface to the spring constant of the pneumatic cylinder 8, it can be achieved that the said balance is established precisely when the air pressure in the spring element 4 exactly neutralizes the acceleration causing the deflection.

With the described arrangement for pressure level control according to the invention, the spring characteristic diagram according to FIG. 5 can be implemented in a simple and functionally reliable manner.

After the end of the acceleration causing the deflection, the car body 1 is again pressed towards the center of the bogie frame 2 by the effect of the air pressure in the left air bellows 4. The pneumatic cylinder 8 moves back into its starting position. But since his piston 81 is still in the shifted position remains because the air pressure in the bellows 4 and in the active volume 83 of the cylinder 8 is still at a higher level, the right control valve 6 is brought into a position in which the air can escape from the left, previously loaded bellows 4. As soon as this happens, the piston 81 is also brought into its starting position by reducing the volume 83 by the spring 82. As a result, the control valve 6 is finally closed again. The car body 1 is again centered over the bogie frame 2, the air pressure in the air suspension bellows 4 is the same on both sides and both control valves 6 are closed. The spring characteristic has now been reduced to the initial level.

In order to dampen vibrations in the transverse suspension, according to a further feature of the invention, a throttle 9 is installed in the connecting line 41 between the spring element 4 and the pneumatic piston 8. This throttle 9 allows the air pressure to be equalized in the case of a longer-lasting pressure difference, but prevents the pressure equalization in the event of short-term and lower pressure differences, so that small and short-term deflections, such as those caused by the rail faults to be compensated or the like, are not regulated by the air pressure from the air spring elements can be included.

In the pneumatic variant of the transverse suspension shown in FIG. 2, two double-acting pneumatic cylinders 4, 4 'are used as spring elements. They act between the body 1 and bogie 2 in the transverse direction. Furthermore, a preferably electrical position measuring system 8 'is arranged between the car body and the bogie. The cylinder bottom side of one cylinder is connected to the cylinder rod side of the other cylinder via a pneumatic line. The cylinders are vented from the compressed air source 7 via electrically operated directional valves 6, 6 ', which are controlled by a preferably electronic control unit 12.

Only the target cylinder pressure is specified in the controller 12, a separate control circuit being implemented in the pressure control unit 13 for constant control of the pressure. The associated scheme for controlling the pneumatic variant is shown in FIG. 6. The cylinder pressure is measured by means of pressure sensors 9 and converted into an electrical signal which is processed in the pressure control unit 13 separately from the control unit 12. Fig. 4 shows the force level to be controlled as a function of the transverse path. In the area designated I, the target force level and thus the target pressure of the cylinders are kept constant. If the transverse path increases and you leave area I, the pressure setpoint is increased at a defined speed. When leaving the area towards the center, the pressure setpoint is reduced at a defined speed. The range in which the setpoint does not change is chosen so large that the dynamics of the bogie to the body, but not the shift due to centrifugal forces, does not result in a change in the setpoint. Since the cylinder pressure is constant in this area, a constant force is introduced. The required flat characteristic curve is achieved with a higher force level. Fig. 5 shows a transverse spring diagram in which with A the characteristic of the secondary springs, with B the characteristic of the secondary springs plus a stop buffer, with B 'the characteristic like B, but with the maximum additional transverse force initiated by the active transverse spring system, and with C the area in which, according to the control, the characteristic curve B is shifted in parallel depending on the static transverse load.

The hydraulic variant shown in Fig. 3 solves the problem underlying the invention so that a supply unit 10, with an oil pump 11, 11 'for each cylinder, two hydraulic cylinders 3, 3' installed horizontally between the body 1 and bogie 2 'with pressurized oil . Single-acting plunger cylinders are preferably used. There is one in the return line to the tank Proportional pressure relief valve 5, 5 'switched, which regulate the target pressure in the cylinders. The electrical signals for the proportional pressure relief valves 5, 5 'are calculated by the preferably electronic control. As with the pneumatic solution, the cross travel is used as the input signal. The target pressure of the cylinders is calculated according to the same logic as described for the pneumatic variant.

The setpoint pressure of the cylinders is already regulated hydraulically in the valves, so that the control circuit shown schematically in FIG. 7 results for the hydraulic variant. It is therefore not necessary to measure the cylinder pressure and return it to the control. With this advantageous control arrangement, the required increase in the force level of the secondary spring can be carried out in a simple manner. When the displacement measuring system 8, 81 is integrated into the hydraulic cylinders 5, 5 ', the number of components is reduced to a minimum: a pressure oil supply unit, two hydraulic cylinders with attached valves and an integrated displacement measuring system and an electronics unit.

The transverse suspension described is designed by means of the arrangement according to the invention for regulating the pressure level in such a way that a soft spring characteristic is provided for small deflections, which can be raised to a force level corresponding to the free acceleration of acceleration by means of the active control. The control is designed so that it only adjusts larger deflections and allows small movements to work on the flat spring core line. This results in a certain tolerance range around a defined target value as the work area, the target value of the force level increasing with the transverse path.

Claims (17)

Arrangement for controlling a transverse suspension between the bogie and the body of a rail vehicle, comprising at least two spring elements acting in the transverse direction and based on fluid pressure, which are provided with controllable valves for adjusting the pressure of their operating medium, characterized by a displacement measuring system (8, 81) for the deflection in Transverse direction between bogie (2) and car body (1), which is connected to a control unit (12), which according to a predetermined function for each value of the deflection of the car body (1) determined by the position measuring system (8, 81) relative to the bogie (2 ) actuates at least the control valve (5, 5 ', 6, 6') associated with the compressed spring element (3, 3 ', 4, 4'). Arrangement according to Claim 1, characterized in that a pneumatic cylinder (8) or the element (61) is used as a combination of position measuring system and mechanical control device between an element (61) actuating the respective control valve (5, 5 ', 6, 6') ) itself is designed as a pneumatic cylinder, which is attached to the bogie frame (2), preferably to its stop pin (3), and whose piston (81) is displaceable against the action of a spring (82), the active volume (83) of the cylinder (8) is pneumatically connected to the spring element (4) controlled via the associated control valve (6) via a line (41), so that there is a balance between the air pressure in the spring element (4) and the force of the spring (82) at one Can adjust the position of the piston (81) at which the control valve is again in the closed position. Arrangement according to claim 2, characterized in that a throttle (9) is installed in the connecting line (41) between the spring element (4) and the pneumatic piston (8). Arrangement according to Claim 1, characterized in that an electronic control unit (12) is provided in which a program is stored which, in accordance with a predetermined function, compares the deflection of the car body (1) with each value determined by the preferably electrical position measuring system (8 ') the bogie (2) causes a control signal to at least the control valve (5, 5 ', 6, 6') associated with the compressed spring element (3, 3 ', 4, 4'). Arrangement according to claim 2 or 3, characterized in that the control influence of the control unit (12) is directly proportional to the determined value from a predetermined limit value for the deflection and the setpoint pressure rises more steeply with the deflection from the limit value than below it, where the control unit ( 12) produces no control effect influencing the position of the control valves (5, 5 ', 6, 6'). Arrangement according to Claim 2, 4 or 5, characterized in that the control influences dependent on the determined pressure values correspond to a predetermined function of the difference between the setpoint value and the determined value, so that the pressure at least in the compressed spring element (3, 3 ', 4, 4 ') is constantly regulated. Arrangement according to claim 6, characterized in that the control gain is equal to 1, so that the target pressure is completely corrected. Arrangement according to claim 6, characterized in that the control gain is less than 1, so that the target pressure is not completely corrected. Arrangement according to one of claims 1 to 8, characterized in that the spring elements pneumatic cylinders (4, 4 ') and pressure sensors (9, 9 ') for determining the pressure of the medium in the spring elements (4, 4') are provided and connected to the pressure control unit (13), in which preferably a program for comparing the determined pressure values with the corresponding function defined setpoints and which, in the event of a difference, sends control signals to at least the control valve (5, 5 ', 6, 6') associated with the compressed spring element (4, 4 '). Arrangement according to claim 9, characterized in that the valves are electrically operated directional valves (6, 6 '). Arrangement according to claim 9 or 10, characterized in that double-acting pneumatic cylinders are provided and the cylinder bottom side of each cylinder is connected to the cylinder rod side of the other cylinder. Arrangement according to one of claims 1 to 8, characterized in that the spring elements are hydraulic cylinders (3, 3 '). Arrangement according to claim 12, characterized in that the hydraulic cylinders (3, 3 ') are connected to a tank (10) for the hydraulic fluid via separate oil pumps (11, 11'). Arrangement according to claim 12, characterized in that the valves (5, 5 ') are controllable proportional pressure relief valves. Arrangement according to claim 12, characterized in that the valves (5, 5 ') are controllable servo valves. Arrangement according to claim 12, characterized in that the valves (5, 5 ') are controllable pressure reducing valves. Arrangement according to one of claims 12 to 16, characterized in that the electronic control unit (12) contains a program for deriving a value for the speed of the deflection, which for each value of the speed has a control signal corresponding to a predetermined damper characteristic to at least that of the compromised one Spring element (3, 3 ') associated control valve (5, 5') releases.

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