EP3116762B1 - Obstacle detection device for railway vehicles - Google Patents

Description

Technical area

The present invention relates to a device for obstacle detection in rail vehicles with a track clearer which is attached to the bogie of a rail vehicle by means of a holding device.

State of the art

A foreign object lying on the route of a rail network can pose a significant risk in the event of a collision. Rail traffic technology has therefore long been familiar with rail clearers or track clearers, which can be used to clear an obstacle from the track. A track clearer usually consists of a steel structure with a collision bar lying transversely to the direction of travel. The collision bar is attached to the main frame of the rail vehicle or to the bogie frame using a mounting bracket. Various regulations on the construction and operation of a rail vehicle stipulate that such a track clearer must be installed in front of the first wheelset in the direction of travel and as close as possible to the top edge of the rail.

In the EP 2 548 783 A2 For example, collision detection is proposed for a rail vehicle in which a track clearer is held by means of a mounting bracket, whereby a guided design of the track clearer with respect to the mounting bracket is released when a predefined intensity of the collision is exceeded. Obstacle detection in the sense of a differentiated detection of the collision object is therefore not possible. Known lane clearers have the disadvantage that a statement about the collision can only be made in the form of a yes-no decision. If the intensity of the collision is below a predetermined threshold, the collision is not recorded at all. If the intensity of the collision was greater, it remains unknown how great it actually was.

However, rail vehicle operators are increasingly demanding that obstacle detection detects collisions in a more differentiated manner. For example, obstacle detection should be able to detect a specified mass limit, such as 5 kg, as reliably as possible and, if necessary, initiate emergency braking of the rail vehicle.

document KR 100 837 174 B1 discloses a device for obstacle detection in a rail vehicle, with a track clearance bar which is held by means of a mounting bracket in front of the first wheelset in the direction of travel on the bogie frame of the rail vehicle, wherein the mounting bracket is formed by two vertically arranged spring elements, each spring element is designed as a leaf spring and is fastened at an upper end to the bogie frame and at a lower end to the track clearance bar, wherein each leaf spring is subjected to bending in the event of a collision, wherein the mounting bracket is formed by the two leaf springs which are spaced apart from one another by a distance which corresponds to the width of the bogie frame.

Description of the invention

It is an object of the present invention to provide a device for obstacle detection in rail vehicles such that a more precise statement about the collision mass is possible and which can be manufactured as simply and inexpensively as possible.

This object is achieved by a device having the features of claim 1. Advantageous embodiments of the invention are defined in the dependent claims.

According to a basic idea of the invention, spring elements are used both for mounting the track clearing beam and for measuring the force-time curve in the event of a collision. The mounting bracket of the track clearing beam is formed by vertically arranged spring elements, preferably leaf springs. each leaf spring being attached at an upper end to the bogie frame and at a lower end to the track clearing beam. Each leaf spring has a Measuring transducer in the form of a strain-voltage converter. This measuring transducer is arranged between the upper end and the lower end on a broad surface of a leaf spring and is connected to an on-board evaluation unit via a signal-conducting connection. This makes it possible to detect an obstacle in a differentiated manner and not only when it exceeds a fixed collision limit value. Disturbing influences that occur at increased driving speeds can be better taken into account for subsequent actions. This means that unintentional braking operations occur less frequently.

In terms of susceptibility to interference, it is advantageous if the measurement signal generated by the force measuring device is fed to a signal preprocessing unit on site, i.e. by means of a device arranged on the web clearer holding device. The measurement signal can be an analogue or digital signal, for example. It is advantageous if the measurement signal is checked for plausibility and forwarded to an evaluation unit as an amplified signal.

According to the invention, the track clearer holding device is formed by at least two vertically arranged spring elements, each spring element being attached to the bogie at an upper end and to the track clearer at a lower end. The vertical arrangement ensures that the dead weight of the track clearer does not rest on the measuring transducer. As a result, the measuring device is not subjected to shear forces.

In terms of manufacturing costs, it can be advantageous if the strain-voltage converter is a piezoelectric measuring transducer or a strain gauge.

Unintentional braking can be prevented in particular if the speed of the rail vehicle is taken into account. This means that unintentional braking occurs less frequently, especially at higher driving speeds.

It is advantageous if the electronic evaluation unit is designed as a digital computer and is integrated into a safety loop or an electronic vehicle bus. This means that a braking command generated by the evaluation unit can be forwarded directly to the corresponding actuator or reported to the driver.

According to the invention, a simple and robust design is constructed in such a way that the mounting bracket is formed by two vertically arranged leaf springs, which are spaced apart from one another by a distance approximately equal to the width of the bogie frame. Each leaf spring acts like a clamped beam that is subjected to bending in the event of a collision, and at the same time as a force sensor that sends a time-dependent force signal to the evaluation unit.

Short description of the drawing

To further explain the invention, reference is made in the following part of the description to drawings from which further advantageous embodiments, details and further developments of the invention can be seen on the basis of non-limiting embodiments.

Show it:

Figure 1

an embodiment of the invention, in which the hanging suspension of the track clearing beam by means of two vertically arranged leaf springs is shown in a schematic representation;

Figure 2

an enlarged view of a leaf spring from Figure 1 , in which the measuring device is shown enlarged;

Figure 3

a block diagram showing the connection between the measuring device and the evaluation device as well as their integration into the safety loop and vehicle bus.

Implementation of the invention

Figure 1 shows a schematic view of a bogie frame 5 of a rail vehicle 1. The bogie frame 5 has a front wheel set 11. In the direction of travel (arrow) in front of this wheel set 11, a track clearance bar 6 arranged transversely to the direction of travel is sketched. This track clearance bar 6 is attached to the bogie frame 5 by means of a mounting bracket 7.

As explained in more detail below, the mounting bracket 7 not only forms a mechanical suspension for the track clearing beam 6, but also functions as a force sensor which, in the event of a collision with an obstacle, converts the collision force occurring into a proportional electrical signal and transmits it to an electronic evaluation unit.

The mounting bracket 7 is designed as a suspended construction. In the embodiment shown, it consists essentially of two vertically arranged spring plates or leaf springs 8. Each of these leaf springs 8 is made of a spring steel with a rectangular cross-section. This spring steel 8 is attached to the bogie frame at an upper end 9. A lower end 10 of each leaf spring 8 is connected to the track clearance beam 6, which is arranged transversely to the direction of travel. The connection can be made by screwing, riveting or welding. Each leaf spring 8 is in the In the event of a collision, the beam is subjected to bending like a beam clamped on one side.

The distance 17 between the leaf springs 8 corresponds approximately to the width of the bogie frame. For bogies mounted on the outside, the distance is slightly larger than the track width, and for bogies mounted on the inside, it is slightly smaller than the track width.

The leaf springs 8 are dimensioned in terms of their material properties and their cross-section in such a way that the vibrations and shocks occurring during driving, particularly at higher speeds, do not have a disruptive effect on obstacle detection.

If a collision occurs with an obstacle on the rail or in the rail bed, the suspension structure is bent backwards towards the wheel set 11. This deflection of the leaf springs 8, which is opposite to the direction of travel, is a measure of the size of the obstacle cleared away by the track clearance beam 6. The elastic deformation of the spring steel 8 is measured by means of a measuring device 2, 3 ( Figure 2 ) is measured. By recording the temporal progression of the force signal during the collision, a differentiated detection of the collision object is possible.

A spatial arrangement of this measuring device 2,3 is shown in the schematic representation of the Figure 2 . On a broad surface 12 of a leaf spring 8, a strain-voltage converter 2 with an associated measuring amplifier 3 can be seen. The strain-voltage converter 2 and the measuring amplifier 3 are arranged between the upper end 9 and the lower end 10 on the same broad surface 12 of the leaf spring 8. Holes are shown at the upper and lower ends, with which the leaf spring is screwed to the bogie frame or to the track clearance beam.

As already mentioned, the arrangement of leaf spring 8 and strain-voltage converter 2 functions as a force-displacement converter: The strain-voltage converter 2 converts the elastic deformation of the leaf spring 8 that occurs when it collides with an obstacle into a proportional electrical voltage signal. This voltage signal corresponds to an analog force-time curve. The signal is initially fed via the connecting line 4 to a measuring amplifier 3 assigned to the measuring converter 2. The measuring amplifier 3 amplifies the signal of the strain-voltage converter 2 on site to a corresponding analog level so that the signal transmission is less susceptible to interference.

The amplified electrical signal then passes from the measuring amplifier 3 via the connecting line 4 to an electronic evaluation unit 13 located on board the rail vehicle 1. The connecting line 4 supplies the energy for the measuring transducer 2 and the measuring amplifier 3 on the one hand, and the signal line to the evaluation unit 13 on the other. In the following embodiment, the external unit is a digital computer.

In the evaluation unit 13, after a signal analysis, a comparison is made with a trigger threshold value that depends on the vehicle speed. If the processed measurement signal exceeds a predetermined threshold value, a safety loop 15 is opened directly and emergency braking of the rail vehicle 1 is initiated. If the processed measurement signal remains below a predetermined threshold value, a message is sent to the driver via an internal vehicle bus 16. The threshold value is specified by the evaluation unit depending on the speed and, if necessary, other driving parameters, for example acceleration and impacts.

The advantage of the invention is that a collision is not only considered as a threshold value, as is usual up to now. is not only monitored, but an obstacle can be detected in a differentiated manner. This means that the trigger threshold can be set depending on the severity of the collision and the vehicle speed. This means that undesirable braking occurs less frequently.

The mounting bracket made of spring steel is mechanically robust and easy to manufacture. Commercially available components can be used as strain-voltage converters. A piezo or strain measuring strip can be attached to the leaf spring in a simple and cost-effective manner using an adhesive connection. Overall, the manufacturing costs of the suspension of the track clearing beam, which is designed as a force sensor, are comparatively low.

Although the invention has been illustrated and described in detail by preferred embodiments presented above, the invention is not limited to the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the claims.

List of reference symbols used

1

Rail vehicle

2

Strain-voltage transformer

3

Measuring amplifier

4

Connecting line

5

Bogie frame

6

Track clearing bar

7

Mounting bracket

8th

Spring element, leaf spring

9

top end

10

lower end

11

Wheel set

12

Wide area

13

Evaluation unit

14

Speed signal

15

Safety loop

16

Vehicle bus

17

Distance between 8

Claims (4)

1. Device for detecting obstacles for a rail vehicle (1), comprising a pilot beam (6) which is attached to the bogie frame (5) of the rail vehicle (1) in front of the leading wheelset (11) by means of a mounting bracket (7), wherein the mounting bracket (7) is constituted by two vertically disposed spring elements (8), wherein each spring element (8) is implemented as a leaf spring and is fixed at an upper end (9) to the bogie frame (5) and at a lower end (10) to the pilot beam (6), wherein each leaf spring (8) is subject to bending stress in the event of collision, wherein each spring element (8) has a stress-strain converter (2) which is disposed between the upper end (9) and the lower end (10) on a broad surface (12) of a spring element (8), and wherein each stress-strain converter (2) is connected to an on-board evaluation unit (13) via a signal-carrying connection (13), wherein the mounting bracket (7) is constituted by the two leaf springs (8) spaced apart by a distance (17) corresponding to the width of the bogie frame (5), wherein each leaf spring acts as a fixed beam which is subject to bending stress in the event of collision, and simultaneously as a force sensor which transmits a time-dependent force signal to the evaluation unit (13), wherein the evaluation unit (13) is configured to compare a measurement signal with a threshold value dependent on a vehicle speed following a signal-related analysis, after which a direct opening of a safety circuit (15) takes place and emergency braking is initiated if the measurement signal exceeds the threshold value, or after which, via an internal vehicle bus (16), an indication is made to a driver if the measurement signal remains below the threshold value, wherein the stress-strain converter (2) is designed as a strain gauge, and wherein the evaluation unit (13) is linked to the safety circuit (15) and to the electronic vehicle bus (16).
2. Device according to claim 1, wherein the signal-carrying connection (13) passes via a measuring amplifier (3) assigned to the stress-strain converter (2), wherein the stress-strain converter (2) and assigned measuring amplifier (3) are both disposed on the broad surface (12) of the leaf spring (8).
3. Device according to claim 2, wherein the stress-strain converter (2) is a piezoelectric transducer.
4. Device according to claim 1, wherein a speed signal (14) of the rail vehicle (1) is fed to the evaluation unit (13), which signal is taken into account for initiating a braking operation.

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