Device for detecting track sleepers

Abstract

An apparatus for detecting sleepers on a track is described, which comprises a sleeper detection sensor (11), which is arranged on a track construction machine, possibly on a track inspection car assigned to the track construction machine, for inspecting and determining the position of the sleepers (5, 19) on the track. In order to be able to advantageously determine the position of the sleepers, it is proposed that the sleeper detection sensor (11) comprises a magnet generating a magnetic field (14, 15) in a magnetic circuit with at least one air gap between the sleeper detection sensor (11) and the track, and a Hall sensor (13) arranged in the magnetic circuit, wherein a Hall voltage (U) of the Hall sensor (13), which varies in the longitudinal direction (A, s) of the track, is used to determine the position of the sleepers (5, 19) on the track.

Description

[Technical field]

[0001] The present invention relates to a device for detecting sleepers on a track, comprising a sleeper detection sensor which is arranged on a track construction machine, possibly on a track inspection car assigned to the track construction machine, in order to inspect and identify the position of the sleepers on the track. [Background technology]

[0002] Sleeper detection sensors of this kind are used in particular to measure and identify the position of the metal fastening means connecting the rail to the sleeper, so that the position of the sleeper can also be unambiguously determined.

[0003] A tamping machine is a machine for leveling track. For this purpose, a measuring system is used, which measures the actual position of the track height, the actual position of the track direction and the actual position of the track during the operation and compares them with predefined target values. The track is lifted and aligned laterally by the track lifting and leveling unit until the difference between the predefined target position and the actual position is zero, and is fixed in this position by compacting the ballast under the sleepers with the help of the tamping unit. The lifting and leveling of the track is carried out in this case via suitable hydraulic lifting and leveling cylinders with proportional or servo control. The tamping tool of this type of track construction machine must be driven exactly in the middle area between the sleepers in order to prevent destruction and breakage of the sleepers. Therefore, great attention must be paid to the exact positioning of the tamping machine with the tool. Automatic positioning and forward running of the track construction machine is possible if the sleepers are recognizable and are not covered by a layer of ballast.

[0004] In addition to maintenance work, compactors are also used for compacting the track in a new position after ballast screening or track renewal. These work are characterized by several compaction operations. These compaction operations are characterized by the fact that the track is ballast loaded up to the top edge of the rail and the compactor performs large lifts. The position of the sleeper is only roughly recognized by the operator during the lift by the clearly formed ballast relief. The problem here is that the compactor operator can only perform the machine forward travel and position the compaction tool over the intermediate range on the basis of feeling and experience. In this case, automatic forward travel is practically excluded. If the positioning of the compaction tool is incorrect, the tool will collide with the sleeper, which will be damaged. Another disadvantage arises, which is that the machine performance is significantly adversely affected.

[0005] Various optical systems, for example with laser scanners or video cameras, can detect the position of the rails, sleepers and rail fastenings, which allows automatic and precise positioning of the compaction tool and the forward travel of the compaction machine. However, known optical methods are not useful for tracks that are ballasted up to the top edge of the rails.

[0006] Another problem with ballasted tracks is that the machine operator does not see obstacles in the intermediate area, such as the switches, switch mechanisms and switch locking devices that are often present at switches, and which are damaged by the tamping unit during the tamping operation. Here too, optical measuring methods are of no use.

[0007] Common inductive and capacitive analog sensors have a detection distance of up to about 30 mm. However, there is a much larger distance between the upper edge of the rail and the height position of the rail fastening means to be detected, so that sensors of this type have not been used effectively so far. Thus, for example, the guidance of inductive sensors is problematic in that the sensor must be set low and therefore travel through the ballast. Furthermore, there is the difficulty that the fastening means have different heights depending on the type, which is likewise problematic in view of the short measurement intervals. In practice, many different rail fastening means exist. Rail fastening means are characterized by bolted fastenings, which are at least mainly made of steel (a ferromagnetic material). These fastening means are located in the immediate vicinity of the rail, have a low magnetic mass and are partially below the upper rail edge, which cannot be reliably detected with known inductive or capacitive sensors. In principle, the sensor can detect the fastening means if it has descended close enough to the fastening means for the measurement. However, if the rail edge is ballast loaded, such a solution is practically no longer possible. Summary of the Invention [Problem to be solved by the invention]

[0008] The problem underlying the present invention is therefore to find a detection instrument and a unit which avoids the above-mentioned disadvantages and which is guided at a large distance relative to the rail fastening means (above the ballast) even when fully loaded with ballast and which detects the rail fastening means unambiguously. [Means for solving the problem]

[0009] The present invention solves the problem set out in that the sleeper detection sensor comprises a magnet generating a magnetic field in a magnetic circuit with at least one air gap between the sleeper detection sensor and the track, and a Hall sensor arranged in the magnetic circuit, the Hall voltage of the Hall sensor varying in the longitudinal direction of the track being used to determine the position of the sleeper on the track. Advantageous developments of the invention are presented in the dependent claims.

[0010] A magnetic field is generated in the magnetic circuit via electromagnets and permanent magnets, which is measured by a Hall sensor through which a current flows, the Hall voltage of which increases due to the presence of the rail fastener resulting in a decrease in the magnetic reluctance, the increase in voltage being used to determine the position of the rail fastener and thus the sleeper in the longitudinal direction of the track and to control the automatic forward movement of the track construction machine. Mainly the air gap and thus the magnetic reluctance varies depending on whether the rail fastener or possibly also other mechanical obstacles such as points are present or not. This applies in particular between two sleepers. The course of the Hall voltage over the track length, i.e. the respective position of the sleeper detection sensor on the track, is used to determine the position of the rail fastener and thus the sleeper in the longitudinal direction of the track.

[0011] The magnetic circuit is closed via the rail between two sleepers. When a rail fastener enters this magnetic interaction zone, the magnetic resistance decreases and the magnetic field increases. Before the compaction unit is positioned, the rail fastener is detected at several sleepers, and thus the change in the magnetic field and the sleeper position are measured, so that the signals can be evaluated in advance and the center position can be determined.

[0012] The Lorentz force that relates vectors to a magnetic field is valid:

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[0013] The Hall effect sensor, operated with a known current I, measures the magnetic field component By which occurs perpendicular to the plane of the Hall effect sensor. An electric field Ex is generated. A voltage U can be measured laterally, proportional to the electric field Ex. The sleeper detection sensor is attached to a support car and guided at a constant height above the rail and the rail fastening. The traveled distance and the Hall voltage are continuously measured. The signal is evaluated. For this purpose, successive boundary values ​​are determined starting from the difference between the base level and the peak value of the signal. From the average value of the signal at this boundary value, the average position of the rail fastening and therefore the position of the sleeper is obtained. The measured distances ai per sleeper are used for the forward travel control and positioning of the compaction tool.

[0014] The advantage of this embodiment according to the invention is the measurement through the ballast layer and thus the possible precise positioning of the compaction tool, which allows the compaction machine to be operated at high speed in the automatic forward travel mode. With several sleeper detection sensors arranged side by side on the bogie, the unit is also able to detect obstacles made of ferromagnetic material, for example the drive mechanism for a switch in the mid-section. [Brief description of the drawings]

[0015] The drawings illustrate the subject matter of the invention in a schematic manner. [Figure 1] FIG. 1 shows a sleeper shown in partial cross section with a rail and a W-shaped fastener. [Diagram 2] FIG. 1 shows a sleeper shown in partial cross section with a rail and a K-shaped fastener. [Diagram 3] 1 shows a schematic diagram of a sleeper detection sensor structure together with a magnetic field. [Figure 4] 1 shows the basic structure of a Hall effect sensor. [Diagram 5] 2 shows a schematic representation of the measurement sequence and the resulting voltage signal at the Hall sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Figure 1 shows in cross section a rail 1 bolted onto a sleeper 5 with a gradient of 1:40. Shown are the sleeper bolt 2, the tension clamp 3, the angle guide plate 4 and the pad 6. The tension clamp 3, the sleeper 5 and the sleeper bolt 2 are made of steel and therefore affect the magnetic flux change when the sleeper detection sensor moves along the rail 1. This allows their longitudinal position on the track to be detected unambiguously.

[0017] Figure 2 shows another type of rail fastening, the so-called K-fastening (clamping plate). On a sleeper 5, the rail 1 is bolted with a gradient of 1:40. Shown are a T-bolt 7 with fastening nut, a clamping plate 8, a sleeper bolt 9, a ribbed plate 10 and an elastic pad 6. The T-bolt 7, the ribbed plate 10 and the clamping plate 8 are made of steel and reduce the magnetic resistance when the sleeper detection sensor moves over the K-fastening.

[0018] Fig. 3 shows diagrammatically the measurement structure of the sleeper detection sensor 11 referred to here. The sleeper detection sensor 11 is arranged on a track construction machine, not shown, possibly on a track inspection car assigned to the track construction machine, in order to measure and determine the position of the sleepers 5, 19 on the track. The sleeper detection sensor 11 comprises an electromagnet 12 which generates a magnetic field in a magnetic circuit with at least one air gap between the sleeper detection sensor 11 and the track, and a Hall sensor 13 arranged in the magnetic circuit. The Hall sensor 13 is arranged in this case in this air gap between the sleeper detection sensor 11 and the track. The Hall voltage U, which changes when the sleeper detection sensor 11 moves in the track longitudinal direction A, s, i.e. along the track, is used to determine the position of the sleepers 5, 19 on the track.

[0019] The sleeper detection sensor 11 is equipped with an electromagnet 12. Via the electric coil of the electromagnet 12 and the magnetic core 11, in particular the soft iron core of the sleeper detection sensor 11, a magnetic field 14, 15 is generated which is introduced into the rail head. The soft iron core of the sleeper detection sensor 11 is formed approximately in a U-shape. The magnetic core 11 is guided in the same longitudinal direction with a small gap on the rail head or slides directly on the rail head with one leg of the soft iron core. It is also possible to introduce a magnetic field into the rail head via the wheel. If there is no rail fastening, the magnetic circuit is closed at the other end of the magnetic core 11, i.e. directly via the other leg of the soft iron core, towards the rail head of the rail 1. The end of the other leg of the magnetic core is guided essentially on a possibly present rail fastening and supports the Hall sensor 13 on its contact surface against the air gap in this embodiment. The Hall sensor 13 is thus arranged in the magnetic circuit.

[0020] In the region of the sleeper fastener, the magnetic field is changed by the additional coupling of the magnetic field 14 via the rail fastener, in particular the sleeper bolt 2 or the T-bolt 7, towards the end of the magnetic core where the Hall sensor 13 is mounted. The magnetic resistance decreases, the magnetic field becomes stronger and the measured Hall voltage U increases. The magnetic core 11 may be formed from several layers of thin plates, in particular mutually insulated transformer plates, for reasons of improving magnetization.

[0021] 4 shows a Hall effect sensor 16 with a magnetic field By flowing through it. A current I flows through the Hall effect sensor and can be tapped through a contact which generates a voltage U in the Hall effect sensor transverse to the current I and proportional to the magnetic field By. The Hall voltage generated is

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[0022] As the relationship shows, the generated voltage U is directly proportional to the current I, the material-specific Hall constant RH, and the magnetic field BY. As the thickness d of the Hall layer increases, the voltage U decreases.

[0023] FIG. 5 shows the mode of operation diagrammatically. The sleeper detection sensor 11 is guided at a constant height along a rail 18 in the direction A. The rail 18 is connected via fastening means 17 to the sleepers 19 at sleeper intervals ai. Furthermore, the course of the Hall voltage U measured over the track length s is shown. In the absence of fastening means 17, a voltage level 22 is measured. In the area of ​​the metallic rail fastening means 17, the Hall voltage U increases to 21. Here, the position of the fastening means 17 and the sleeper 19 together with the fastening means 17 can be determined. From the difference between the voltage peak 21 and the base level 22, a boundary value 20 between both values ​​is continuously determined. By the average value of the intersections of the stress peak 21 with this boundary value 20, the position of the fastening means 17 and thus the position of the sleeper 19 is obtained.

Claims

1. A device for detecting track sleepers, comprising:

1. An apparatus comprising a sleeper detection sensor (11) arranged on a track construction machine, possibly on a track inspection car assigned to the track construction machine, for inspecting and determining the position of sleepers (5, 19) on the track, the sleeper detection sensor (11) comprises a magnet generating a magnetic field (14, 15) in a magnetic circuit having at least one air gap between the sleeper detection sensor (11) and a track, and a Hall sensor (13) arranged in the magnetic circuit, wherein a Hall voltage (U) of the Hall sensor (13) which varies in a longitudinal direction (A, s) of the track is used to determine the position of a sleeper (5, 19) on the track.

2. 2. The device according to claim 1, characterized in that the magnet is an electromagnet (12) and / or a permanent magnet.

3. 3. The device according to claim 2, characterized in that the current coil of the electromagnet (12) is connected to a DC power supply to generate a DC magnetic field (By) in a magnetic circuit.

4. 3. The device according to claim 2, characterized in that the current coil of the electromagnet (12) is connected to an alternating current source to generate an alternating magnetic field (By) in a magnetic circuit.

5. 2. The device according to claim 1, characterized in that a number of sleeper detection sensors (11) are arranged next to each other in the transverse direction of the track for detecting metal parts between the sleepers (5, 19).

6. 2. The device according to claim 1, characterized in that, in order to search for metal parts on the track, at least one sleeper detection sensor (11) can be displaced in the transverse direction of the track by a movement device assigned to the track construction machine and / or to the track inspection vehicle.

7. 2. The device according to claim 1, characterized in that at least one sleeper detection sensor (11) is arranged on the track construction machine and / or on the track inspection vehicle in a height-adjustable manner relative to the track.

8. 2. The device according to claim 1, characterized in that the Hall sensor (13) is arranged in the air gap.

9. 2. The device according to claim 1, characterized in that the control device continuously determines boundary values ​​(20) between the voltage peaks (21) and the base level (22) of the Hall voltage (U) from the differences between the voltage peaks (21) and the base level (22) of the Hall voltage (U) over the length of the track, and determines the position of the sleeper (5, 19) on the track from the average value of the intersection points between each voltage peak (U) and the boundary value (20).

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