EP0100513B1 - Spring suspension for independent wheels of rail vehicles - Google Patents

Description

The invention relates to a suspension for individually sprung idler wheels of rail vehicles.

For bogie rail vehicles with wheelsets, the two wheels of which are firmly connected to each other by a shaft, it is customary to mount the axle bearings arranged near the ends of the wheelsets each via a first spring device, which can consist of several springs arranged parallel to one another, if necessary for reasons of rigidity support massive bogie frame, which in turn supports the vehicle frame or body via a second spring device, which may also consist of several parallel single springs (FR-A 22 18 229). If one of the vehicle wheels is subjected to an upward shock load, the first spring device assigned to the axle bearing adjacent to this vehicle wheel is compressed by increasing its tension, this spring device slightly raises the part of the bogie frame located above it and the bogie frame thereby becomes inclined. This inclined position has the effect that the lifting caused by the first spring device is transmitted at a reduced gear stroke with only about half to a quarter of the lifting height to the bearing point of the second spring device on the vehicle frame. As a result of this stroke reduction by inclining the bogie frame relative to the horizontal plane, impact loads on the vehicle wheels in bogie vehicles are largely reduced to the vehicle frame or body.

In these known suspensions, the individual spring elements can be designed differently from one another, for example one of the spring elements can be a helical spring and the other one can be an air spring (DE-PS 1 146519). Even taking the gear ratio into account, a compromise must generally be made in such a way that on the one hand the suspension is sufficiently soft and thus the ride with the vehicle is sufficiently comfortable, but on the other hand it is so hard that when the vehicle wheels are subjected to shock loads, they do not spring through to an emergency stop, the deflections are intercepted in good time before the emergency stop takes effect. For this purpose, the suspensions are often designed progressively, in such a way that they generate disproportionately increasing restoring forces when deflecting to the compression stroke. When the vehicle is loaded, however, this results in overall hard cushioning.

From CH-A 205746 a bogie rail vehicle without continuous wheel sets is known, the two wheels on each side of each bogie being only rotatable about their wheel axes in a longitudinal member; a spring device is arranged between each wheel and its longitudinal member. A crossbar of the vehicle body lies rotatably on the longitudinal beams in each case about a vertical axis, with no further spring device being located between the longitudinal beams and the vehicle body. In this arrangement, too, a wheel lift via its spring device leads to a local lifting of the associated longitudinal member, whereby the latter and also the crossbeam are inclined and thus transmit the lifting movement reduced to about a quarter of its value to the vehicle body. Here, too, shock loads on the wheels are greatly reduced by lever reduction.

In known rail vehicles with individual sprung idler wheels, i.e. wheels, each of which can be rotated about its own vertical axis, the mentioned bogie frames and longitudinal members or cross members lack comparable parts, so that the shock loading of these idler wheels is reduced by the suspension devices without lifting reduction by lever-like structures be transferred to the vehicle frame or body. The vehicles with idler wheels thus have the disadvantage over bogie vehicles that shock loads on the vehicle wheels are transmitted to the vehicle to a greater extent because the wheel deflections are not translated both in terms of their lifting height and their lifting speed as in the bogie vehicles.

It is an object of the invention to design a suspension of the type mentioned at the outset, that is to say for rail vehicles with idler wheels, in such a way that they are able to absorb and cushion shock loads on the vehicle wheels without undue large strokes.

This object is achieved according to the invention by training according to the characterizing part of patent claim 1, 2 or 3.

The advantageous design and execution options for the suspension according to the further invention can be found in the dependent claims 4 to 12.

• Fig. 1 Federungskennlinien,
• Fig. 2 und 3 zwei unterschiedliche Ausführungsformen einer gleichartigen Federungsgrundanordnung,
• Figur 4 bis 6 eine Ausführungsform einer zweiten Federungs-Grundanordnung in drei unterschiedlichen Federungszuständen,
• Figur 7 eine weitere Ausführungsform der Federungs-Grundanordnung nach Fig. 4
• Figur 8 eine Einzelheit aus Fig. 7 in geänderter Ausführung und
• Figur 9 eine weitere Ausführungsform der Federung.

In the drawings, the function and the schematic structure of suspensions designed according to the invention are shown, for example, and shows

• 1 suspension characteristics,
• 2 and 3 two different embodiments of a similar basic suspension arrangement,
• FIGS. 4 to 6 show an embodiment of a second basic suspension arrangement in three different suspension states,
• FIG. 7 shows a further embodiment of the basic suspension arrangement according to FIG. 4
• 8 shows a detail from FIG. 7 in a modified version and
• Figure 9 shows another embodiment of the suspension.

To meet the problems described above for suspensions of the type mentioned at the beginning tik is to strive for a characteristic curve for the suspension, which is shown in Fig. 1, wherein F is the spring force exerted by the suspension, s the stroke of the suspension and t the time period during which the shock load of the wheel continues. For short-term impacts (t = small), the spring characteristic initially rises very gently and only after a certain stroke (s ₁ ) does a steeply increasing characteristic curve branch follow. According to this characteristic, short-term impacts cannot transmit correspondingly high force peaks to the vehicle, because within the first spring stroke with a very soft suspension, the force introduced - the shock load - already drops again. Additional shock absorbers which do not enter the characteristic curve and which are to be arranged parallel to the suspension can prevent a rocking by several such impacts. In the case of a correspondingly longer impact load on the vehicle wheel, the characteristic curve t = medium applies, after which a transition from the initially flat to the steeper characteristic part takes place after only a smaller deflection stroke s ₂ ; the earlier curve break prevents the suspension from compressing too much. In the event of long-lasting force on the vehicle wheel - long-lasting impact load or permanent load on the vehicle - the spring characteristic corresponds to the line t = large; the suspension generates restoring forces corresponding to the deflection stroke right from the start of its deflection, as a result of which the deflection stroke as a whole is limited to permissible values.

If a suspension of the type mentioned is designed such that at least one of the spring elements, but not all spring elements of the suspension are arranged to be relieved of short-term shock loads on the wheel, a suspension characteristic curve can be achieved, at least similarly to Fig. 1: With short-term shock loads, only some of Spring elements effective, whereby a soft suspension with a flat spring characteristic can be set, and only after some time lasting shock loading of the wheel will the other spring elements also become effective, which makes the suspension harder and the spring characteristic is therefore steeper.

In the exemplary embodiment of the suspension according to FIG. 2, a vehicle wheel 1 with a wheel bearing 2 assigned to it is shown. A first spring element 3, designed as a helical spring, is supported on the wheel bearing 2 and carries a seismic mass 4. On the seismic mass 4 there is a second spring element 5, which carries a vehicle frame or possibly directly the vehicle body 6. The first spring element 3 is thus arranged between the wheel bearing 2 and the seismic mass 4 and the second spring element 5 between the seismic mass 4 and the vehicle frame or vehicle body 6. A shock-insensitive part of the vehicle undercarriage, for example a vehicle part corresponding to a heavy bogie frame, can serve as seismic mass 4. In the event of an impact on the vehicle wheel 2, a force is generated in accordance with the wheel movement in the first spring element 3, which initially cannot move the seismic mass 4 due to its inertia, but rather can only set it in motion slowly. The seismic mass 4 moves correspondingly slowly towards the vehicle frame 6, thus generating a relatively slowly increasing and accordingly small increase in force in the second spring element 5. When the shock load of the vehicle wheel 1 subsides as soon as possible, the spring element 5 is practically not influenced by the shock load, the entire shock absorption is accomplished by the first spring element 3. The heavier the seismic mass 4 can be formed, the smaller the impact components are transmitted to the vehicle frame or vehicle body 6 by the second spring element 5.

In order not to have to provide unnecessarily large, seismic masses 4 - such a mass for each vehicle wheel, a seismic mass 4 'according to FIG. 3 can also be assigned to a plurality of vehicle wheels 1, 1'. The first spring element 3 assigned to the vehicle wheel 1 is supported on its wheel bearing 2 and the first spring element 3 ', which is assigned to the vehicle wheel 1', on its wheel bearing 2 '. Both first spring elements 3 and 3 'together carry the seismic mass 4', from which in turn one or more second spring elements extend in a manner not shown, corresponding to FIG. 2, to the vehicle frame or vehicle body 6. 3 preferably on the vehicle frame or vehicle body 6 in such a way that it is at least about horizontal axes which are perpendicular to the connecting line of the two vehicle wheels 1 and 1 'and possibly further ones not shown in FIG. 3 and with their first spring elements also extend to connecting lines extending to the seismic mass 4 'of the wheels, are held non-rotatably, but are vertically displaceable. In the event of an impact on one of the vehicle wheels 1 or 1 ', the entire seismic mass 4' is then impact-reduced or the second spring element relieves the impact, so that the mass of the seismic mass 4 'doubled to FIG. 1 is obtained without doubling the total for that The seismic mass to be provided for the vehicle is a double-effective shock elimination for the vehicle frame 6. Only when the vehicle wheels 1 and 1 'are subjected to a simultaneous impact does the arrangement according to FIG. 2 again result in corresponding shock loads for the vehicle frame 6.

4, the suspension is designed with two pressure medium suspensions 7 and 8 as spring elements. The pressure of the two pressure medium suspensions 7 and 8 can be controlled in a manner not shown in terms of their pressure by conventional control valves which become effective with a delay, depending on the vehicle load. The two pressure medium suspensions 7 and 8 are arranged parallel to one another between the wheel bearing 2, which is only indicated in FIG. 4, and the vehicle frame or body 6. Both pressure medium suspensions 7 and 8 each have a cylinder body 9 or 10 connected to the vehicle frame or body 6, in which a piston 11 or 12 coupled to the wheel bearing 2 is movable. The Interiors 13 and 14 of the cylinder bodies 9 and 10 are filled with the suspension medium air, a gas or a liquid; it can be provided for the two interiors 13 and 14 different suspension medium. With hydraulic filling, a usual gas bubble, not shown in FIG. 4, must be provided in each case. From the interior 13 of the cylinder body 9, a pressure medium line 15 leads via a shut-off valve 16 into a cylinder chamber 18 separated from a piston 17 by the interior 14 of the cylinder body 10. The shut-off valve 16 belongs to a control device (not shown) which normally keeps the shut-off valve 16 closed , and only opens with a time delay from the start of a shock load on the vehicle wheel until after the initial suspension state is reached again; to open the shut-off valve 16, the control device can be triggered by the increase in load on the wheel bearing 2 occurring at the start of the impact, the reduction in distance between the wheel bearing 2 and the vehicle frame 6 or by the pressure increase in the suspension medium, in particular in the interior 13. When the shut-off valve 16 is closed, the pressure medium located in the cylinder space 18 can be displaced from this cylinder space 18 without any appreciable increase in pressure. For this purpose, a soft pressure accumulator can be connected to the cylinder space 18 via a further shut-off valve.

4, its parts assume the positions shown, the pistons 11 and 12 are in a certain rest position, the piston 17 is in a middle position, in which the interior 14 and the cylinder space 18 have a certain volume have, and in the rooms 13, 14 and in the cylinder chamber 18 there are certain pressures corresponding to the vehicle load to be borne by the suspension, which pressures can be different according to the piston surfaces or, if all pistons have surfaces of the same size, the same height. The shut-off valve 16 is closed.

If a shock load occurs on the vehicle wheel assigned to the suspension, as can be caused, for example, by driving over a rail joint, then the wheel bearing 2 is pressed upward and reaches the raised position shown in FIG. 5, in which the two pistons 11 and 12 are pressed into the cylinder bodies 9 and 10 by a stroke distance corresponding to the stroke distance of the wheel bearing 2. The deflection stroke is denoted by s in FIG. In this deflection process, the pressure in the interior 13 rises when the shut-off valve 16 is initially closed, so that the pressure medium suspension 7 exerts a spring force which increases with the deflection stroke. The pressure in the interior 14, on the other hand, practically does not increase during the deflection process, at most only to a very small extent, since the piston 17 deviates in the direction of the cylinder chamber 18 without increasing the pressure in the cylinder chamber 18 in accordance with the deflection stroke. The suspension state shown in FIG. 5 is thus achieved.

If the shock load of the vehicle wheel only lasts for a very short time, the shock load already subsides again while the suspension state is still in accordance with FIG. 1 and the increased spring force of the pressure medium suspension 7 springs the vehicle wheel with the wheel bearing 2 back into the starting position shown in FIG. 4, wherein the piston 17 also returns to the position shown in FIG. 4. The shut-off valve 16 remains closed during the entire suspension process. With this short shock load, only the spring force of the pressure medium suspension 7 was increased, but not that of the pressure medium suspension 8, the suspension thus showed an overall soft characteristic with a low spring constant and the shock load was kept away from the vehicle frame or box 6.

If, however, starting from the suspension state according to FIG. 5, the shock load of the vehicle wheel continues, the suspension reaches the suspension state illustrated in FIG. 6. After a certain period of time from the start of the impact or after reaching a certain deflection stroke, the control device opens the shut-off valve 16, at the same time care being taken to ensure that a pressure increase takes place in the cylinder chamber 18, for example by shutting off the aforementioned pressure accumulator by closing the second shut-off valve, which has also already been mentioned can. From the higher pressure inner space 13, pressure medium then flows through the pressure medium line 15 and the shut-off valve 16 into the cylinder space 18 and presses the piston 17 toward the piston 12 while increasing the volume thereof, so that the volume of the inner space 14 is reduced and in this Interior pressure medium 14 thus experiences an increase in pressure. Assuming the same piston area, as already mentioned above, there are the same pressure levels in the interior spaces 13 and 14 and in the cylinder space 18, so that now not only the pressure medium suspension 7, but also the pressure medium suspension 8 exerts an increased spring force. The suspension thus becomes harder overall, receives a higher spring constant, and the compression process is ended immediately without exceeding a permissible compression stroke. After the increased force acting on the vehicle wheel due to the long-lasting impact has subsided, the suspension springs out again and all parts return to the rest position shown in FIG. 4. The control device then closes the shut-off valve 16 again and connects the piston chamber 18 to the pressure accumulator, if necessary.

4 to 6, the spring characteristic of the pressure medium suspension 8, but not the pressure medium suspension 7, is increased as a function of the deflection time and / or the deflection stroke when certain limit values are exceeded, as a result of which different suspension characteristics according to FIG. 1 can be achieved.

In a modification of the exemplary embodiment according to FIG. 4, it is also possible to provide conventional air spring bellows instead of the cylinder bodies 9 and 10, only a different type of suitable device for changing the spring constant of the pressure medium spring 8 being provided instead of the piston 17 with the cylinder space 18. Furthermore, it is not necessary for the pressure medium from the interior 13 itself to act directly on the piston 17; it is also possible to design the control device in such a way that the spring constant of the pressure medium suspension 8 can be changed by acting on the piston 17 from a separate pressure medium source which is independent of the interior 13 or in a completely different manner belonging to the prior art.

To further clarify the mode of operation of the suspension according to FIG. 4 in the positions according to FIG. 4 to FIG. 6, it is assumed below that a pressure medium pressure p _o prevails in the interior spaces 13, 14 and the cylinder space 18 when the piston surfaces are at rest. Furthermore, p means pressures that prevail in the interior or cylinder space determined by the index number. The letters K mean forces which are exerted according to the pressure medium suspension 7 or 8 determined by the added index number. F should finally represent the force that exerts the entire suspension, F thus corresponds to the sum K ₇ + K _e . Under these conditions, for example, the individual suspension states according to FIGS. 4, 5 and 6, as described above, can be assigned the following values, the index 0 relating in each case to the idle state according to FIG. 4 of the suspension:

FIG. 7 shows a suspension which essentially corresponds to the suspension according to FIG. 4 and whose parts corresponding to FIG. 4 are provided with reference numbers corresponding to FIG. 4. 4, the pressure transmitter 19 is arranged on the part of the interior 13 in front of the shut-off valve 16 in the pressure medium line 15, so that the shut-off valve 16 monitors the connection of the interior 14 with the pressure transmitter 19. The pressure transmitter 19 is structurally separate from the pressure medium suspensions 7 and 8, but it could also be combined with this to form structural units. Furthermore, the second shut-off valve 21 is shown in FIG. 7, which monitors the connection or disconnection of the pressure accumulator 22 to and from the interior 14 of the pressure medium suspension 8. Finally, in a further modification to FIG. 7, in addition to the pressure medium suspensions 7 and 8, a helical suspension 23 arranged parallel to these is also shown, which is a third spring element for the suspension. 7 corresponds to that of FIG. 4. The function of the suspension according to FIG. 7 corresponds to that as was described for FIGS. 4-6, with only the portion of the spring force being exerted by the suspension Add coil spring 23; the helical suspension 23 can have a linear or progressive characteristic curve depending on the deflection stroke. Further functional explanations for the suspension according to FIG. 7 are therefore unnecessary.

In the embodiment according to FIG. 7 of the suspension, the pressure transmitter 19 has a simple piston 17, so that pressure levels are generally the same on both sides of the piston 17 and the pressure transmitter 19 thus has a pressure transmission ratio between its two sides of 1: 1. FIG. 8 shows a modified version of the pressure intensifier under the reference symbol 19 ', which has a gear ratio which differs from the gear ratio 1: 1. The piston of the pressure transmitter 19 'is designed as a differential piston with two piston surfaces 24 and 25, the differential surface between the two piston surfaces 24 and 25 being subjected to atmospheric pressure. The smaller piston surface 25 can be acted upon by the shut-off valve 16 according to FIG. 7 by the pressure medium pressure in the interior 14 and the larger piston surface 24 by the pressure in the interior 13. After opening the shut-off valve 16 is thus in the pressure medium suspension 8 In accordance with the area ratio of the piston surfaces 24 and 25, the pressure is set higher than in the pressure medium suspension 7, the pressure medium suspension 8 thus exerts a substantially increased spring force after opening the shut-off valve 16, and the suspension as a whole receives a much harder characteristic than when the shut-off valve 16 is closed. The ratio the piston surfaces 24 and 25 can be selected according to the respective requirements, it is also possible to choose it in reverse to the embodiment according to FIG. 8.

9 again two pressure medium suspensions 26 and 27 are provided, the one pressure medium suspension 26 being constantly connected to a relatively small pressure accumulator 28, so that this pressure medium suspension 26 has a relatively large spring constant and is accordingly hard. The pressure medium chamber of the other pressure medium suspension 27 is in the idle state of the suspension via a switching valve 29 belonging to the control device already mentioned; as indicated by the solid lines in the switching valve 29, a relatively large pressure medium reservoir 30 is assigned, such that this pressure medium suspension 27 has a small spring constant in the idle state of the suspension and is therefore correspondingly soft. In the case of only brief deflection processes, that is to say brief shock loads on the vehicle wheel, only the pressure medium suspension 26 thus changes its spring force in accordance with the deflection processes, while the pressure medium suspension 27 exerts a relatively constant spring force. The suspension thus has a relatively soft characteristic overall during these brief suspension processes. However, if the deflection processes or shock loads last for a long time, the switching valve 29 is switched over from the switching position described above to the switching position shown in dashed lines in FIG. 9, with a time delay at the start of these suspension processes, the pressure medium suspension 27 being separated from the pressure medium accumulator 30 and sent to the Pressure medium accumulator 28 is connected in addition to the pressure medium suspension 26. This also gives the pressure medium suspension 27 a high spring constant and exerts correspondingly high spring forces, so the spring constant of the suspension as a whole is increased so that the long-lasting, increased wheel loads cannot penetrate through the suspension, but, as already mentioned above, before exceeding one permissible deflection stroke can be intercepted. 9 corresponds to the basic principles described above, so that it does not need to be explained further here.

Also in the embodiment according to FIG. 9, a pressure transmitter 19 or 19 ′ corresponding to the embodiment according to FIGS. 7 or 8 can of course be arranged in the connecting line 31 from the pressure medium reservoir 28 or the pressure medium suspension 26 to the switching valve 29 or from the switching valve 29 to the pressure medium suspension 27 will. The pressure medium accumulators 22, 28 and / or 30 can be designed as simple containers, but, as indicated in FIG. 9, they can also have a piston or a corresponding membrane acted upon by the pressure medium and on the other hand by a spring force. The gaseous or hydraulic basic filling of the pressure medium suspensions 26 and 27 can, as already mentioned above, take place by means of delayed, conventional control valves - height control valves or air suspension valves. 9, it is finally also possible to connect the pressure medium suspension 27 by means of the switching valve 29 not to the pressure medium accumulator 28, but to a third pressure medium accumulator, which is constantly separate from the pressure medium suspension 26 and which the pressure medium suspension 27 achieves the required increase in its spring constant gives.

The control device for switching the shut-off valves 16, 21 and / or 29 can expediently have an electrical resonant circuit which, according to its frequency at the start of a wheel shock load, controls the valves mentioned by means of electrical pulses and triggers their switching. The delay time for the switching of the shut-off or switching valves 16, 21 and / or 29 is expediently chosen in accordance with the passage time of rail joints in the order of magnitude of, for example, 0.25 sec in bogie vehicles, if necessary a travel speed-dependent control of the delay time can be provided.

Reference symbol list

Claims (12)

1. Spring suspension for individually sprung independent wheels (1) of rail vehicles wherein at least two spring elements mounted in series in relation to each other (3, 5) are allocated to each independent wheel, the first spring element (3) being arranged between a wheel bearing (2) of the independent wheel (1) and a vertically moveable seismic mass (4) and the second spring element (5) being arranged between the seismic mass (4) and a vehicle frame, possibly the vehicle body (6) such that the second spring element (5) is relieved from instantaneous shock loads of the independent wheel (1) (Fig. 2).

2. Spring suspension for individually sprung independent wheels (1, 1') of rail vehicles wherein the wheel bearings (2, 2') of at least two independent wheels (1, 1') are bearing via a first spring element each (3, 3') on a seismic mass (4') that is allocated in common to at least two independent wheels (1 and 1') and wherein a second spring element belonging to both independent wheels (1 and 1') is arranged to act in series in relation to the first spring element (3, 3') between the seismic mass (4') and a vehicle frame, possibly the vehicle body and wherein the seismic mass (4') is guided at least rotatably and vertically moveable through horizontal axes running at right angles in relation to the joining lines of these vehicle wheels (1, 1'), possibly at the vehicle body (6) such that the second spring element is relieved from instantaneous shock loads of the independent wheels (1, 1') (Fig. 3).

3. Spring suspension for individually sprung independent wheels of rail vehicles wherein at least two spring elements arranged in parallel one in relation to the other are allocated to each independent wheel, these spring elements being fitted between a wheel bearing (2) and the vehicle frame or body and designed as preloaded pressure medium spring suspensions (7, 8; 26, 27) and wherein a control device (shut-off valve 16, control valve 29) is allocated to at least one but not to all pressure medium spring suspensions (8, 27), that permits the spring tension of this pressure medium spring suspension (8 ; 27) of which at least one is provided, to rise during a spring compression process only with a time delay in relation to the spring compression process such that at least one pressure medium spring suspension (8, 27) changes over with time delay from a low to a high spring rate at the beginning of a shock load of the vehicle (1).

4. Spring suspension according to claim 3 wherein the spring rate or spring tension respectively of one pressure medium spring suspension (8, 27) may be increased by means of a pressure medium of the other pressure medium spring suspension (7, 26) that may be directly or indirectly fed in via the control device (shut-off valve 16, control valve 29) that is actuated as a function of spring compression time and stroke.

5. Spring suspension according to claim 4 wherein one pressure medium suspension (7 or 8) features a balancing piston (piston 17) that is maintained in an easily deflectable state in rest condition and is pressurized on one side by its pressure medium and that is pressurized on the other side by the pressure medium of the other pressure medium spring suspension (8 or 7) upon response of the control device (shut-off valve 16) (Fig. 4, 7).

6. Spring suspension according to claim 5 wherein a pressure transformer is arranged at least between one of the pressure medium spring suspensions and the pressurization chamber of the balancing piston allocated to this pressure medium spring suspension.

7. Spring suspension according to claim 5 wherein the balancing piston is designed as a differential piston (piston surface 24, 25) (Fig. 8).

8. Spring suspension according to claim 5 wherein a pressure reservoir (22) can be connected to one pressure medium spring suspension (8) via a control valve (shut-off valve 21) (Fig. 7).

9. Spring suspension according to claim 3 wherein a pressure medium spring suspension (27) may be alternately connected to two pressure reservoirs (30, 28) by means of a control device (control valve 29), whereby one pressure reservoir (30) gives it a low and the other pressure reservoir a high spring rate (Fig. 9).

10. Spring suspension according to claims 3, 4 and 9 wherein the other pressure reservoir (28) is charged with the pressure medium of the other pressure medium spring suspension (26).

11. Spring suspension according to claim 3 wherein the control device is controlled by electric pulses that are possibly generated in an electric oscillator circuit.

12. Spring suspension according to claim 3 or 11 wherein the delay time for the increase of the spring tension corresponds at least approximately to the distance in time for overrunning the rail joints.

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