Hydropneumatic suspension unit as well as hydropneumatic suspension system

Abstract

A hydropneumatic suspension system arranged on a bogie for a vehicle, particularly for a rail vehicle, and one hydropneumatic suspension unit respectively which is contained in the suspension system. For this purpose, the spring accumulator, the reservoir, the tank and the control unit are arranged in the area of the at least one spring strut, so that an essentially self-sufficient suspension unit is obtained. The suspension system may be used and connected to a levelling unit.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] The invention relates to a hydropneumatic suspension unit for a vehicle, particularly a rail vehicle. The invention also relates to a hydropneumatic suspension system which has at least two suspension units of this type, and to a bogie.

[0002] In such suspension systems, the required hydraulic supply and control unit is disposed either in or on the bogie of a car body and is connected with at least one spring strut per body side, or it is arranged on the car body and supplies the spring struts of several bogies. In this case, the spring struts of the two car body sides of a bogie are connected with one another by one overflow valve respectively. The valve is always closed in normal operation and opens only when the pressure in one of the two spring struts drops in an unacceptably excessive manner, for example, as a result of a line snapping. Thus, it is ensured thereby that the vehicle is lowered to a defined emergency support without taking up an inclined position which, as a. rule, does not permit the operation of the vehicle. This overflow function is normally implemented by a valve arrangement on the control plate which, however, requires a high-expenditure tubing of the components of the suspension system distributed in the bogie or in the car body.

[0003] An example of such a hydropneumatic suspension system is known from International Patent Document WO 94/08833. The arrangement illustrated here is used specifically for the level and inclination control of a car body of a rail vehicle, in which case the hydropneumatic suspension has to be capable of controlling a relatively high ratio of the vehicle weights in the fully loaded or empty condition. In addition, this known construction relates to the problem that the vehicle level has to be kept at least approximately constant also during a change of passengers at stops.

[0004] This system is therefore based particularly on the problem that the levelling has to be carried out at a high speed; that is, large amounts of oil can be fed into the hydraulic circuits of the suspension and can be discharged from them respectively in a relatively short time. This problem is solved in that, when a correction requirement is recognized with respect to the level or inclination of the car body, a pump operates directly against the pressure of the hydropneumatic spring accumulator of the suspension damping system and pressure medium will be removed from the reservoir filled during the travel only when the delivery volume of the pump is not sufficient for keeping the level of the car body constant. In particular, as a result, the energy consumption of the overall system is minimized.

[0005] In order to be able to minimize the size of the units, these hydropneumatic suspension systems or control circuits exist in the vehicle several times, in which case each side may comprise only one or several spring struts. The spring struts of the left and right suspension are hydraulically connected with one another, so that one-sided lowerings or lifts of the vehicle can be corrected by overflowing hydraulic fluid.

[0006] However, such distributed systems for a hydropneumatic suspension generally require a high-expenditure casing of the components distributed in the bogie or in the car body. This casing results in high costs; its laying in the bogie is difficult; and there is the danger that the hydraulic system of the hydropneumatic suspension is contaminated by dirt in the lines which may result in an impairment of its functioning. It is another disadvantage that, as a result of the unavoidable relative movements between the individual components on the bogies and the car body as well as between components at different installation sites on the bogie, there is the danger of damage to the line elements and a possible leakage. This may result in a loss of the operability of the entire system.

[0007] It is therefore an object of the present invention to further develop a hydropneumatic suspension unit for a vehicle, particularly a rail vehicle, or a hydropneumatic suspension system such that the casing expenditures can be reduced.

[0008] This object is achieved by a hydropneumatic suspension unit of the present invention.

[0009] It was recognized according to the invention that the casing expenditures can be reduced by a meaningful arrangement of the parts components in the direct proximity of the spring strut. As a result, a type of self-sufficient suspension unit can be achieved which supplies in each case only one or several spring struts on one side of the car body of the bogie. This leads to a very compact construction whose components are subjected to essentially no relative movements with respect to one another. These can therefore be directly coupled to one another, which significantly simplifies the construction and reduces the danger of damage as a result of the dynamic movement of the vehicle when travelling.

[0010] The suspension unit according to the invention is therefore distinguished by low mounting expenditures and high reliability.

[0011] As a special embodiment of the suspension unit according to the invention, the spring accumulator, the reservoir, the tank and the control unit may be arranged on both sides of a spring strut axis. This results in a construction which is compact and continues to be easily accessible with respect to the individual components, which facilitates the mounting as well as the servicing.

[0012] As an alternative construction, the spring accumulator, the reservoir, the tank and the control unit may also be arranged in a star shape around the at least one spring strut, so that all components are present as closely as possible around the spring strut axis. This very compact construction can therefore even better withstand the dynamic stresses occurring during the travel. In addition, the space requirements for the arrangements can be minimized thereby.

[0013] As an additional alternative construction of the spring unit according to the invention, the spring accumulator and the reservoir can be arranged directly at the at least one spring strut, while the tank and the control unit are arranged adjacent thereto at the bogie and are connected by a connection line with the at least one spring strut. This two-part solution has the advantage that the spring system can be manipulated better for the mounting. In addition, the control unit can be mounted at low expenditures for servicing work, particularly without having to remove the spring strut.

[0014] According to another aspect of the invention, a hydropneumatic suspension system is provided, which has at least two suspension units according to the invention which are arranged on both sides on the car body of the vehicle, and, in addition, contains a levelling unit which is assigned to the at least two suspension units.

[0015] The suspension unit according to the invention thereby also utilizes the advantage that a casing within the suspension units will not be necessary. As a result, a very simple modular construction of the suspension system can be achieved which significantly simplifies the mounting. As will be explained in detail in the following, the levelling unit can in this case also be connected without casing expenditures with the suspension units, thereby permitting a constructively particularly simple and very reliable construction.

[0016] Thus, it is, for example, possible that the levelling unit is arranged separately of the at least two suspension units on the bogie or on the car body. The levelling unit will then constitute a separate module which is easy to mount. In addition, the suspension units may be provided as identically designed modules.

[0017] As an alternative, it is possible to assign the levelling unit to a suspension unit, whereby the installation expenditures for the connection lines can be reduced as a whole. Furthermore, no additional devices are required for the fastening of the levelling unit on the bogie or on the car body so that the construction is simplified.

[0018] In this case, the levelling unit can be electronically coupled with the at least two suspension units. In this manner, an overflow function can be implemented without any casing expenditures. Thus, a purely electronic pressure monitoring of the system pressure can take place in the two levelling circuits. Thus, when a previously adjusted differential pressure is exceeded, an electrically actuated drain valve or the like is actuated and thus provides the required pressure compensation. Such a drain valve can already be provided in the levelling unit. In addition, for detecting the pressure in the two suspension units, one electric pressure sensor respectively can be utilized, for example, for the electric load detection. This solution requires a pressure detection of the respective other side by the hydraulic medium itself, because here only signal cables are required between the suspension units. This construction can therefore be implemented at low mounting expenditures and is distinguished by high reliability.

[0019] As an alternative, it is also possible for the levelling unit to have one differential-pressure control valve respectively for each suspension unit, the differential-pressure control valves being mutually connected by pressure gauge lines. A pressure compensation is therefore permitted between two or more self-sufficient suspension units, without the requirement of a fluid mass flow. In this case, such a differential-pressure control valve opens up starting from an adjusted differential pressure between the two suspension units and drains oil from the levelling circuit into the tank of the respective unit until the differential pressure has again reached its predetermined amount. In this case, the oil quantity in each suspension unit does not change, which is why a tank connection line between the two suspension units is not required. This results in very low casing expenditures because the at least two required connection lines between the car sides can be implemented by the pressure gauge line. These have clearly smaller dimensions than hydraulic lines and can be laid at lower expenditures than such hydraulic pipes or hydraulic hoses. In addition, they have a more flexible design, so that the mounting is further simplified.

[0020] Furthermore, it is also possible that the levelling unit has one differential-pressure control valve for each suspension unit, the differential-pressure control valves being connected with the suspension units by hydraulic lines, and the tanks of the at least two suspension units also being connected with one another by a hydraulic line. Despite the required two hydraulic lines, this construction is also still distinguished by essentially reduced casing expenditures in comparison to the prior art because the casing expenditures are clearly reduced as a whole as a result of the decentralization of the suspension units.

[0021] According to another embodiment of the invention, it is also possible that the levelling unit has in each case one differential-pressure control valve respectively for each suspension unit. In this case, each differential-pressure control valve is connected by a hydraulic line with a suspension unit on the other car body side, and the tanks of the at least two suspension units are connected with one another also by a hydraulic line. As a result, the parts components of the system can essentially be integrated in the suspension units, in which case they can, in addition, have an essentially identical construction. The expenditures for providing the suspension system can be significantly reduced thereby. In addition, clearly lower casing expenditures can thereby be achieved in comparison to the prior art because the individual components are combined in suspension units.

[0022] According to another aspect of the invention, a bogie is provided which has such a suspension unit or such a suspension system. Because of the compact construction of the components, the bogie according to the invention is distinguished by particularly low mounting expenditures. In addition, it can be provided at reasonable cost and has a high reliability and service life, in which case the servicing expenditures can also be minimized.

[0023] Other objects, aspects and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 is a simplified perspective representation of a bogie having a hydropneumatic suspension system according to the invention, individual components being omitted for the purpose of clarity;

[0025] FIG. 2 is a perspective view of a suspension unit according to the invention in a first embodiment;

[0026] FIG. 3 is a view of a suspension unit according to the invention according to a second embodiment;

[0027] FIG. 4 is a schematic operational diagram of a first embodiment of the suspension system according to the invention;

[0028] FIG. 5 is a schematic operational diagram of a second embodiment of the suspension system according to the invention;

[0029] FIG. 6 is a schematic operational diagram of a third embodiment of the suspension system according to the invention;

[0030] FIG. 7 is a schematic operational diagram of a fourth embodiment of the suspension system according to the invention; and

[0031] FIG. 8 is a schematic operational diagram of a fifth embodiment of the suspension system according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] According to the representation in FIG. 1, a suspension system in this embodiment has two suspension units 2 each mounted on a frame on a bogie 1 of the vehicle. In this case, the suspension system is used for damping shocks and vibrations of the bogie 1 with respect to the car body of the vehicle which is not shown here and which is arranged above the suspension units 2.

[0033] The active axis of each suspension unit 2 is arranged perpendicular to the wheel axes of the bogie 1. The two suspension units 2 jointly support the car body at a line which is not shown and which connects the upper ends of the suspension units 2 and is situated parallel to the wheel axes. In this case, the suspension system is situated essentially in the center between the wheel axes of the bogie 1. In addition, each suspension unit 2 is arranged outside the respective wheel disk of the bogie 1, an arrangement in the wheel disk plane also being possible.

[0034] As illustrated in the detail in FIG. 2, each suspension unit 2 has a carrier or manifold 21 on which a spring strut 22, a spring accumulator 23, a reservoir 24, a control unit 25 and a tank 26 are fastened. The control unit 25 has an electric motor 251, an electronic control module 252 and valve or pressure transducing units 253. These components are essentially coupled directly to one another through the carrier or manifold 21 so that no casing expenditures are required between the latter. For the purpose of completeness, it should also be pointed out that the suspension unit 2 also has additional valves, level sensors, a hydraulic pump etc. as well as a covering, which are not shown here. The level sensor may be integrated, for example, into the suspension unit 2 or may be mounted externally. As illustrated in FIG. 2, the parts components of the suspension unit 2 are arranged on both sides of the spring strut axis.

[0035] FIG. 3 shows a modified construction in which a suspension unit 2′ is essentially divided into two parts units. On the one hand, the spring strut 22 with the directly flanged-on spring accumulator 23 and the reservoir 24 form a unit on carrier 21A; while the control unit 25 and the tank 26 are provided separately thereof on carrier 21B. A connection line 27 is used as the connection between carrier 21A and 21B which, however, according to the representation, may have a very short length because, in addition, all components are arranged in the area of the spring strut 22. In this case, the connection line 27 is shown as a hydraulic hose.

[0036] FIG. 4 is a schematic operational diagram of a first embodiment of the suspension system according to the invention. In addition to the two suspension units 2, level sensors 4 assigned to each suspension 2 and a joint levelling unit 5 are provided. The level sensors 4 supply corresponding information to the levelling unit 5 which, in turn, emits a control signal to the control unit 25 of each suspension unit 2. Here, the levelling unit 5 can be centrally arranged on the bogie 1, on or in the car body or it can also be assigned to a suspension unit 2. By this construction, an overflow function can be implemented without any casing expenditures because a purely electronic pressure monitoring of the system pressure can take place in the two levelling circuits. In this case, when a differential pressure, which is preferably adjusted with respect to the software, is exceeded, an electrically controlled drain valve is actuated which, as a rule exist for each unit, whereby the required pressure compensation becomes possible. For detecting the pressure in the two suspension units 2, one electric pressure sensor respectively is provided which can be utilized, for example, also for the electric load detection. Thus, no pressure detection of the respective other side is required by way of a hydraulic medium, since in this construction there are only signal cables between the suspension units. The installation expenditures for the required signal cables can be further reduced if the levelling unit 5 is assigned to one of the suspension units 2 or is integrated therein.

[0037] FIG. 5 illustrates second embodiment of the suspension system according to the invention in which the levelling unit 5 has two differential-pressure control valves 51 and 52 which are assigned to the respective suspension units 2. Each differential-pressure control valve 51 and 52 respectively is connected with the other suspension unit 2 by a pressure gauge line or mini gauge line, so that it is provided with the pressure level of this levelling circuit. Starting from a previously set differential pressure between the two suspension units 2, the respective differential-pressure control valve 51 or 52 respectively will open up and will drain oil from the respective levelling circuit into the tank 26 of the suspension unit 2, until the differential pressure again falls below the predetermined limit value. Here, the oil quantity in the suspension system cannot change. Since only two pressure gauge lines are used for the two connection lines between the car body sides, casing expenditures can essentially be avoided. Such pressure gauge lines have significantly smaller dimensions than hydraulic tube lines or hydraulic hoses and can be laid in an easier or more flexible manner. A pressure adjustment is by an offset signal which is transmitted by an upright oil pressure column, which is closed in itself, in a pressure gauge line from one differential-pressure sensor to another differential-pressure sensor of the differential pressure control valves. Thus, no pressure compensation takes place by a fluid mass flow.

[0038] FIG. 6 illustrates a third embodiment of the suspension system according to the invention, here the two differential-pressure control valves 51 and 52 being arranged as a separate unit on the bogie 1 or on the car body. In addition, this construction has one hydraulic line respectively from the levelling unit 5 to the suspension units 2. Another hydraulic line connects the tanks 26 of the suspension units 2 with one another in order to prevent an unacceptably high amount of oil on one car body side in the event of an overflow of oil.

[0039] According to FIG. 7, the differential-pressure control valves 51 and 52 in a fourth embodiment can also be assigned to a suspension unit 2, so that they are not present as a separate module.

[0040] In a fifth embodiment of the present invention according to FIG. 8, the differential pressure control valves 51 and 52 may also each be assigned to the suspension units 2. An additional hydraulic line will then be required in order to form the levelling circuit.

[0041] In addition to the embodiments indicated here, the invention permits additional design principles.

[0042] Thus, some of the components of the electric control unit 25 or additional electric components may be arranged on the bogie 1 or on the car body, the control unit 25 interacting with these components. As a result, the stress on one portion of the electric components can be reduced within certain limits.

[0043] In addition, it is possible to arrange the spring accumulator 23, the reservoir 24, the tank 26 and the control unit 25 in a star-shaped manner around the respective spring strut 22.

[0044] Also, when larger loads are to be absorbed, two or several spring struts 22 can be arranged directly side-by-side, which are then supplied or controlled by a common spring accumulator 23, reservoir 24, tank 26 or a joint control unit 25. Furthermore, spring struts 22 which are arranged on one side of the vehicle in a mutually spaced manner can also be serviced by joint supply and control components.

[0045] When the levelling unit 5 is arranged on the car body or on the bogie 1, it can also control more than two suspension units 2 arranged laterally on the vehicle.

[0046] The invention thus provides a hydropneumatic suspension system for a vehicle, particularly for a rail vehicle, and a hydropneumatic suspension unit respectively which is contained in the suspension system, and by means of which the casing expenditures for the suspension system can clearly be reduced. As a result, the mounting and the maintenance of the system can be significantly simplified.

[0047] Although the present invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The spirit and scope of the present invention are to be limited only by the terms of the appended claims.

Claims

1. A hydropneumatic suspension unit for use on a rail vehicle between a bogie and a car body of the rail vehicle, the unit comprising:

a spring accumulator,

a reservoir;

at least one spring strut;

a tank;

a control unit for controlling the level of the at least one spring strut; and

wherein the spring accumulator, the reservoir, the tank and the control unit are arranged in the area of the at least one spring strut.

2. The hydropneumatic suspension unit according to claim 1, wherein the spring accumulator, the reservoir, the tank and the control unit are arranged on both sides of a spring strut axis.

3. The hydropneumatic suspension unit according to claim 1, wherein the spring accumulator, the reservoir, the tank and the control unit are arranged in a star-shaped manner around the at least one spring strut.

4. The hydropneumatic suspension unit according to claim 1, wherein the spring accumulator and the reservoir are connected directly on the at least one spring strut, while the tank and the control unit are arranged adjacent thereto on the bogie or on the car body and are connected by a connection line with the at least one spring strut.

5. The hydropneumatic suspension unit according to claim 1, wherein the spring accumulator, the reservoir, the tank and the control unit are connected directly on the at least one spring strut.

6. A hydropneumatic suspension system for a rail vehicle, comprising;

at least two suspension units according to claim 1, which are arranged on both sides on the car body of the vehicle; and

a levelling unit coupled with the at least two suspension units.

7. The hydropneumatic suspension system according to claim 6, wherein the levelling unit is located separate from the at least two suspension units on the bogie or on the car body.

8. The hydropneumatic suspension system according to claim 6, wherein the levelling unit is located with one of the suspension units.

9. The hydropneumatic suspension system according to claim 6, wherein the levelling unit is electronically coupled with the at least two suspension units.

10. The hydropneumatic suspension system according to claim 6, wherein in that the levelling unit has one differential-pressure control valve respectively for each suspension unit, and the differential-pressure control valves are mutually connected by pressure gauge lines.

11. The hydropneumatic suspension system according to claim 6, wherein the levelling unit has one differential-pressure control valve respectively for each suspension unit; the differential-pressure control valves are connected with the suspension units by hydraulic lines; and the tanks of the at least two suspension units are connected with one another by way of a hydraulic line.

12. The hydropneumatic suspension system according to claim 5, wherein the levelling unit, for each suspension unit, has one differential-pressure control valve respectively assigned to the respective suspension unit, each differential-pressure control valve is connected by a hydraulic line with a suspension unit on the other car body side; and the tanks of the at least two suspension units are connected with one another by a hydraulic line.

13. A bogie for a rail vehicle including a hydropneumatic suspension system according to claim 6.