WO2012029054A1

WO2012029054A1 - Railway carriage

Info

Publication number: WO2012029054A1
Application number: PCT/IB2011/053871
Authority: WO
Inventors: Enrico Fedi; Maria Taiti
Original assignee: Ansaldobreda SpA
Current assignee: Ansaldobreda SpA
Priority date: 2010-09-03
Filing date: 2011-09-05
Publication date: 2012-03-08
Anticipated expiration: 2013-03-03
Also published as: ES2539137T3; PL2611668T3; EP2611668B1; HRP20150665T1; IT1402175B1; ITTO20100734A1; EP2611668A1

Abstract

A railway carriage (1) having a body (12) and at least one bogie (13) coupled together by two air springs (16), one on the right and one on the left, being part of a pneumatic secondary suspension (17) of an active type; the air springs (16) are supplied with pressurized air by way of respective solenoid valves (20), which are controlled by an electronic control unit (30); the electronic control unit (30) functions in response to signals that are indicative of the vertical distance between the body (12) and the bogie (13), of the pressure in the air springs (16), and the supply pressure; the electronic control unit (30) is also configured to adjust the height of the body (12) with respect to the platform at the stop stations.

Description

RAILWAY CARRIAGE

TECHNICAL FIELD

The present invention relates to a railway carriage provided with pneumatic secondary suspensions.

BACKGROUND ART

As it is known, a railway carriage comprises a body connected by way of secondary suspensions, to bogies provided with wheels. The secondary suspensions dampen the vibration of the body to allow a comfortable journey for carriage passengers. Typically, the secondary suspensions are of hydro-pneumatic or pneumatic type and are associated with a control system that is adapted to adjust the height of the body in function of the load, i.e. the passengers. At the same time, a primary suspension is provided between the axles of the wheels and the frame of each bogie. The primary suspension is generally defined by rubber elements or steel springs.

For the pneumatic secondary suspensions, it is known to use a control system with mechanical control. In particular, as shown in the known prior art of figure 1, the pneumatic secondary suspension comprises two air springs 1, one for the right side and the other for the left side of the bogie, supplied by the respective pressurized air streams, which are adjusted by respective control valves 2. The control valves 2 are fixed with respect to the body 3 (partially shown) and are operated by levers or other mechanical control devices 4, which are mounted on the right side and on the left side of the carriage, are connected to the frame of the bogie 5, and vary the opening of the respective control valves 2 in response to the vertical distance of the control valves 2, and therefore of the body 3 , with respect to the bogie 5.

The control system further comprises:

- two unidirectional valves (not shown) which are arranged parallel with each other and allow air flow between the two air springs 1, in one way or another, when the pressure difference between the two sides of the suspension exceeds a certain threshold, to level the carriage when an air spring is deflated due to failure or when the train stops correspondingly to a curve with a side slope; and

- a valve (not shown) communicating with the two air springs and sending a pneumatic signal, indicative of the average pressure of the springs themselves, towards the braking system of the carriage.

The known solution just described above is not very satisfactory, due to the high number of valves to be installed on the railway carriage and the positioning constraints imposed by the mechanical control devices in the design of the layout of the various components of the suspension.

In addition, any failure of the unidirectional valves are difficult to detect, and the mechanical control devices are exposed to external environmental conditions.

DISCLOSURE OF INVENTION

The aim of the present invention is to provide a railway carriage, which allows to simply and economically solve the problems outlined above. Provided according to the present invention is a railway carriage as defined in claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the annexed drawings, which illustrate a non limitative embodiment, in which:

Figure 1 illustrates, partially and in perspective, a railway carriage of the known art; and

- Figure 2 is a pneumatic diagram illustrating a preferred embodiment of the railway carriage according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION In Figure 2, with 10 is indicated, as a whole, a railway- carriage (schematically and partially illustrated) , comprising a body 12 and a plurality of bogies, only one of which is illustrated and indicated by reference number 13. The bogie 13 comprises a frame and two pairs of wheels, which are coupled to the frame by way of a pneumatic primary suspension (not shown) . The body 12 is connected to the frame of the bogie 13 by way of two air springs 16, of a known type, mounted one on the right side and one on the left side of the bogie 13, and defining part of a pneumatic secondary suspension 17.

The suspension 17 is supplied with pressurized air from a pneumatic line 18, which also supplies the brakes (not shown) of the bogies 13.

The suspension 17 comprises, for each air spring 16, a respective tank 19 and a respective solenoid valve 20, of proportional type. Each tank 19 is connected parallel to the corresponding air spring 16 and to a relative pneumatic attachment 21, known as "test point", throughout a pneumatic line 22. Due to the tanks 19, in all operating conditions the actual frequency of the air springs 19 is that according to project, i.e. in this case less than 1.5 Hz. Due to attachments 21, however, it is possible to connect a pressure gauge to lines 22 in order to measure the pressure within air springs 16.

The solenoids of the valves 20 are connected to an electronic control unit 30 by way of respective lines 29 for receiving electrical control signals. Each of the valves 20 comprises a three-way pneumatic connection, indicated by reference letters V, L and E. The way V is connected to line 18 by way of a pneumatic line 31, the way L is connected to the line 22 and, therefore, adapted for supplying pressurized air to the corresponding air spring 16, and the way E is connected to the external environment so as to define a discharge. Under resting conditions, i.e. in absence of the electrical control signals and, therefore, with the solenoid de-energized, the moving elements of valves 20 are arranged in a central position, so as to block the ways V, L and E and, therefore, maintaining constant stiffness of air springs 16, with equal load (i.e. passengers). In response to electrical control signals the moving parts of the valves 20 are moved in one direction or another with respect to the central position, for supplying the lines 22 and sending pressurized air in the air springs 16 or, respectively, for discharging the lines 22. In this way, the valves 20 adjust the flow of pressurized air that enters /exits with respect to the air springs 6 and therefore adjusting the height of the left and right sides of the body 12.

The unit 30 is connected to the following components of the suspension 17 :

- two position sensors 32, which are arranged respectively on the sides of the carriage 10 and provide, by way of respective electrical lines 33, signals indicative of the relative position between the frame of the bogie 13 and the body 12 on said sides; for example, position sensors 32 are defined by rotary transducers that detect the height of the air springs 16;

- an electrical control line 34, which transmits, to a braking system and/or a driving system (not shown) , a signal indicative of the average pressure of the air springs 16, and/or the deformation of the springs themselves and/or the load supported by the suspension (deriving from the above mentioned deformation) ;

- two pressure transducers 36, which are arranged on the lines 22, i.e. downstream of the valves 20, and provide, by way of respective electrical lines 37, signals indicative of the pressure of the air springs 16;

- two pressure transducers 38, which are arranged on the lines 31, i.e. upstream of the valves 20, and provide, by way of respective electrical lines 39, signals indicative of the supply pressure.

In particular, for each side of the suspension 17, the valve 20 and the transducers 38 and 36 are integrated into a single unit or body 40, which is mounted in a fixed position on the bogie 13 and has three openings or pneumatic connections, corresponding to the ways L, E and V described above, at least one electrical input for the line 29, and two electrical outputs on the lines 37 and 39.

The unit 30 is configured with appropriate control strategies for performing the following tasks :

- maintaining the height of the body 12 on each side, in a predetermined optimum range, on the basis of the signals of the lines 33, compensating for load changes (i.e. passengers) at the stations;

- maintaining the pressure difference between the air springs 16 at a value below a maximum threshold (e.g. 2.5 bar), on the basis of the signals of the lines 37, for example, by discharging the most inflated air spring, so as to level the body 12 when a spring is deflated due to malfunction, or when the train stops at a curve with a side slope;

- calculating the average pressure in the air springs 16, on the basis of the signals of the lines 33, and sending an electrical control signal through the line 34;

- adjusting the height of the body 12 at the stop stations, on at least the side for boarding/exiting the carriage 10, making sure that access to the door of the carriage 10 is preset at a convenient level with respect to the level of the platform;

- compensating the deformation of the primary suspension as the load increases, by proportionally increasing the height of the air springs 16, in particular according to the stiffness of the primary suspension and the load upon the carriage (deriving from the deformation of the air springs 16) ;

- compensating for the wheel wear, for example, according to measurements of the diameter of the wheels themselves, carried out periodically in either a manual or automatic way.

Regarding the leveling of the body 12 with respect to the platform at the stop stations, the carriage 10 is provided with additional sensors for measuring the relative position between the body 12 (or the doors) and the platform. Alternatively, instead of providing additional sensors, the unit 30 may have a memory containing data concerning the relative position between the platform and the rails at the stop stations along the itinerary, or it can receive said data by way of a wireless transmission system from stop station control units, so as to adjust the height of the body 12 on the basis of the comparison between the measurements of the position sensors 32 and said data. Obviously, avoiding additional sensors requires a series of preliminary experimental measurements in each stop station, for determining which data to store or transmit to the unit 30 . When pressurized air is supplied to the air springs 16 , the unit 30 sets the electrical control signals for adjusting the opening degree of the moving parts of valves 20 and, therefore, the air passage section of the valves 20 , in response to the pressure difference between lines 22 and 31 , on the basis of measurements of the transducers 36 and 38 . In this way, the unit 30 finely adjusts the inlet air flow flowing to the air springs 16 and therefore the inflation time . From the foregoing it is evident that the suspension 17 has a very low number of valves, i.e. only the two valves 20 , which, under the control of unit 30 , are able to perform different tasks. In fact, the unit 30 runs and controls in a closed loop functions that are normally performed by at least four separate valves in the pneumatic secondary suspension of the known art . The reduction of the number of valves to be installed implies a simplification of lines of the entire pneumatic system and a simplification of its maintenance.

Moreover, the suspension 17 is without mechanical control devices, resulting in reduced size and greater freedom in designing the layout of the suspension components. Thanks to the active type suspension 17, with respect to the secondary pneumatic suspension of the known art in which the valves are operated by mechanical control devices, it is possible to automatically adjust the height of the body 12 with respect to the platform of the stop stations to allow more comfort to passengers boarding/exiting, particularly passengers with disabilities. In addition, it is possible to automatically compensate for the deformation under load of the primary suspension in order to always maintain a substantially equal height of the body 12 from the ground.

During maintenance procedures, the attachments 21 also allow to verify if the signals of the transducers 36 are correct; and the transducers 38 allow for decisive and fine control in adjusting the air flow flowing through the valves 20.

Finally, it appears clear from the foregoing, that to the described carriage 10 changes and variations can be made without going beyond the protective scope of the present invention, as defined in the appended claims.

In particular, the transducers 38 may be absent, or only one could be provided, separated from the valves 20. Even the transducers 36 may be separated from the valves 20, instead of being part of the same unit 40.

Claims

1. A railway carriage (10) comprising:

• a body (12 ) ,

• at least one bogie (13),

· a pressurized-air supply line (18) , and

• at least one pneumatic secondary suspension (17) comprising: a) two air springs (16) , which are arranged respectively on the left and right sides of the bogie (13), connect a frame of said bogie (13) to said body (12) and adjust the vertical distance between the body (12) and the bogie (13);

b) two control valves (20) arranged between said supply line (18) and, respectively, said air springs (16) and operated to adjust airflows to and from said air springs (16) ;

characterized in that said control valves (20) are solenoid valves, and in that said pneumatic secondary suspension (17) further comprises :

• at least two position sensors (32) configured to provide respective signals indicative of the vertical distance between the body (12) and the bogie (13) at respective sides of said railway carriage (10) ;

• two pressure transducers (36) configured to provide respective signals indicative of the pressures in said air springs (16 ) ;

• an electronic control unit (30) connected to said position sensors (32) and pressure transducers (36) to receive said signals and connected to the solenoids of said control valves (20) to control the airflow adjustment.

2. A railway carriage according to claim 1, characterized in that said pneumatic secondary suspension (17) comprises at least one further pressure transducer (38) placed upstream of said control valves (20) and connected to said electronic control unit (30) to provide a signal indicative of the pressure in said supply line (8) .

3. A railway carriage according to claim 1 or 2, characterized in that, for each side of the railway carriage (10) , said pressure transducers (36) and said control valves (20) form part of a single unit (40) having:

• three pneumatic connections respectively communicating with said supply line (18) , with the corresponding air spring (16) and with the outside environment;

• at least one electrical input for the electrical command signal from said electronic control unit (30) ;

• at least one electrical output for the signal of one of said pressure transducers (36) .

4. A railway carriage according to any of the previous claims, characterized in that said control valves (20), with the solenoid not energized, close the air outlet of said air springs (20) .

5. A railway carriage according to any of the previous claims, characterized in that said electronic control unit (30) is configured to keep said vertical distance within a predetermined optimal range.

6. A railway carriage according to any of the previous claims, characterized in that said electronic control unit (30) is configured to keep the pressure difference between said air springs (16) at a value below a maximum threshold.

7. A railway carriage according to any of the previous claims, characterized in that said electronic control unit (30) is configured to calculate the average of the pressures in said air springs (16) and send an electrical signal indicative of said average to an electrical control line (34) .

8. A railway carriage according to any of the previous claims, characterized in that said electronic control unit (30) is configured to adjust the height of said body (12), on at least the side for boarding/getting off said railway carriage (10) , with respect to the level of the platform at the stop stations.

9. A railway carriage according to any of the previous claims, characterized by comprising a primary suspension placed between the wheels and the frame of said bogie, and in that said electronic control unit (30) is configured to compensate the deformation of the primary suspension as the load increases, by proportionally increasing the height of said air springs (16) .

10. A railway carriage according to any of the previous claims, characterized in that said electronic control unit (30) is configured to compensate wear on the wheels, by proportionally increasing the height of said air springs (16) .