WO2011029526A1

WO2011029526A1 - Method and device for recording forces occuring during travel on rail-bound axles

Info

Publication number: WO2011029526A1
Application number: PCT/EP2010/005175
Authority: WO
Inventors: Jürgen LIPPEL
Original assignee: SUYUR ALI
Current assignee: SUYUR ALI
Priority date: 2009-09-12
Filing date: 2010-08-24
Publication date: 2011-03-17
Anticipated expiration: 2012-03-12
Also published as: DE102009023204A1; DE212010000145U1

Abstract

The invention comprises a rail vehicle wheel set, comprising a wheel set shaft with two wheel discs comprising: - at least two sensors, which are spaced from each other in an arrangement along the wheel set shaft, each comprising a transducer and a pick-up, of which one is arranged in a non-rotating manner and the other is arranged to rotate with the shaft; the transducer being arranged annularly round the wheel set shaft or arranged on the end face of the wheel set shaft as a disc, and the transducer having radially arranged fields producing alternating signal behaviour; the pick-up detecting the alternating fields and producing a signal; - a comparison unit that compares the signals of the two sensors with each other, and produces an alarm when the signals deviate by a preset threshold value.

Description

Method and device for recording forces occurring during travel on rail-bound axles

The invention relates to a method and a device for recordin forces occurring during travel on rail-bound axles, particularly constant velocity, speed, torque, temperature and/or vibration behaviour of the axle body, for early detection of damage to the axle or the rails.

Description of the invention:

Speeds and axle loads are increasing due to commercial reasons. Therefore, it is absolutely essential for various reasons to recognize the resulting effects both on the vehicle and on the superstructure. Furthermore, rail damage and (track damage) can be detected if the data from a plurality of axles is compared with GPS data. Of relevant importance are the forces occurring between wheel and rail and a deviation from these forces between different wheels arranged on a shaft. For example, if one of the wheels displays a defect, sooner or later this will affect the axl or even the whole train.

Measuring wheel sets for determining the forces occurring between wheel and rail are known from DE 42 18 929 CI, WO 00/20831 and DE 31 14 499 Al, in which eight measuring sensors are arranged per radius, for example four measuring sensors being located on the wheel disc inner face and four measuring sensors being located on the wheel disc outer fac In this arrangement, at least two measuring radii per wheel disc are present. To determine the measured value, eight measuring sensors (Rl to R8) in a measured radius are connected to two Wheatstone bridge circuits, two measuring sensors being connected on the wheel disc inner face and two measuring sensors on the wheel disc outer face. Strain gauges, in particular, are used as measuring sensors and are bonded onto the wheel disc.

A wheel set for rail vehicles with measuring sensors, particularly strain gauges, for recording forces occurring during travel spaced at different radii arranged on the wheel discs is known from DE 10 2005 051 498 83 2007.04-26. In the prior art, eight measuring sensors (Rl to R8) are arranged per radius, four measuring sensors (Rl, R4, R5, R8) being located on the wheel disc inner face and four measuring sensors (R2, R3, R6, R7) on the wheel disc outer face.

According to the invention, eight additional measuring sensors are attached to the wheel disc, each being applied 45° offset to the previous measuring sensors and connected to two additional Wheatstone bridge circuits, whereby, depending on requirements and design of the wheel set, measuring sensors are bonded to the wheel disc on at least one and up to four radii, said sensors are assigned to two different coordinates systems, and two linearly independent equations per radius can be obtained for determining the forces.

The object of the present invention is to present a method and a device that records abnormal forces during operation, in order to give early warning to the train conductor, train driver, service point (workshops, disposition) .

This object is achieved by a method and a device according to the independent claims . A possible solution lies in observing a rail vehicle wheel set that normally includes a rigid wheel set shaft with two permanently arranged wheel discs. If one of these wheel discs displays unusual torque behavior compared to the other wheel disc, this is detected and a warning is triggered. For this purpose, preferably two sensors (it can also be more) are present that produce sensor data, which are compared with each other. In the preferred embodiment, the sensors are arranged with maximum proximity to the wheel discs or shaft ends, whose quality they are intended to check. The sensors have a transducer and a pick-up/encoder each, one of which is arranged in a non-rotating manner and the other arranged to rotate with the shaft. In the preferred embodiment, the transducer is designed to be rotating and the pick-up is attached in a stationary manner to the wheel frame/wheel bearing or the brake caliper. Depending on the arrangement, the transducer can be arranged annularly round the wheel set shaft or as a disc on the end face of the wheel set shaft. Naturally, it is also conceivable that the transducer is arranged directly on the lateral face of the wheel set. In an annular configuration, the transducer can be arranged in the vicinity of the brake, and the pick-up can be attached for example to the brake caliper. In a disc-shaped configuration, this disc can be attached to the head of the wheel set shaft and the pick-up to the axle bearing housing. Attaching the pick-up to the bearing housing or bearing housing cover has the advantage that subsequent servicing is simplified.

The transducer has radially arranged fields and signalling segments which produce alternating signal behaviour. In an optical scanner via a pick-up, these are annular or circula segments or even slits each in a different color. In an inductive system, these can be magnets or metal elevations, which are arranged segmentally.

The pick-up detects the alternating of the fields and produces a signal. This signal is normally configured as a wavelike or square wave shape.

The signals thus produced from both sensors are compared with each other using a comparison unit. The comparison unit can be arranged, for example, in a sensor housing so that there is a cable connection to one sensor and a wireless (e.g.

radio) to the second sensor. The comparison unit can comprise a standard processor or even a digital signal processor.

However, the comparison unit can also be arranged in the centre of the wagon, the train or a stationary exchange. Then data are normally transmitted by radio or by cable. When the signals are compared, deviations are detected which produce an alarm at a preset threshold value or the occurrence of a defined pattern. For example, the signals can be subtracted from each other and, if a specific differential value is exceeded, an alarm is produced. However, deviation patterns can also be detected that always reoccur because of the rotation .

In a preferred embodiment, the transducer is rigidly arranged on the head or round the head of the wheel set shaft and thus rotates with it. The transducer can be constructed as a thin metal ring and attached to the wheel set shaft via the screws that are already being used to bed the wheel set shaft. The housing of the pick-up is designed in such a way that it can be attached to the existing axle bearing housing from inside or from outside. Thus, it is conceivable that the bearing housing is provided with holes, which on the one hand allow the pick-up access to the transducer and on the other hand permit the pick-up housing to be screwed to the axle bearing housing. Using this approach, it is possible to adapt simple axle bearing housings in order to provide them with a pickup. In the illustrated embodiment, the pick-up housing is screwed to the bearing housing from the outside. In an alternative embodiment, the pick-up housing is screwed to th inside of the bearing housing. A suitable small structure is necessary for this purpose as well as suitable metal protection .

In a further preferred embodiment, the power supply is supplied by batteries or by a generator. In this arrangement the batteries are located in the transducer housing and the generator is driven by the shaft (e.g. according to the principle of a flywheel magneto) . The generator can be driven, for example, by a magnetically constructed sensor scribe in the transducer. The rotating magnet can drive a rotor in a generator, which produces electricity and temporarily stores this in a battery if necessary.

A further aspect is shown by the communication of the individual sensors with the comparison unit and the

production of alarms by the comparison unit. As already mentioned above, communication is partly by radio. In this arrangement, license-free frequencies for example of around 2.4 GHz or higher (e.g. 5 GHz) can be used. It is also conceivable that data are transmitted over the GSM/UMTS/WLAN network to an exchange. Furthermore, it is conceivable that each axle has a comparison unit, which carries out its own calculations in each case. When a deviation occurs, the deviations are sent to an exchange/relay in the train or to stationary control unit/control centre. The exchanges can either inform the train conductor or put in place an appropriate rail-signal control, so that the train stops in the event of damage. In addition, the axles communicate with each other. In order to achieve this, either a multi-hop mesh network can be installed where each network participant is also a router/switch and passes on the network traffic, or there are repeaters that pass on the signals each time.

Through the communication between several wheel set shafts, the individual wheel set shaft can ascertain whether it is in a curve or has travelled over a point. Thus, the first wheel set shaft can inform that it is in a curve or has travelled over a point and passes this information on to the other wheel set shafts, which may detect the same. Due to the plurality of deviations in all wheel set shafts, the

comparison unit can now take into account the influence of the point or the curve on the wheel discs and correct it in the calculation or ignore the deviations. A curve is

recognized using a specific pattern of torque curves or using GPS data and knowledge of the track bed. Thus, it is also conceivable that the individual wheel set shafts are

additionally fitted with GPS sensors and provided with mapping material, from which the track section can be seen so that each sensor can independently record whether it is in a curve or travelling over a point. Suitable curve sensors or centrifugal forces sensors can also be inserted, which analyse such forces. However, the communication between the shafts permits a plurality of data to be exchanged precisely in order to establish whether there is a deviation caused by the rail section or whether there is actually a problem with a wheel disc.

In the event of a warning, the identity optionally also with GPS data can now be notified by radio to the locomotive driver using a special identifier in the comparison unit so that the driver can ascertain which wagon possibly has damage . Furthermore, the comparison unit has a memory in which the measurement data can be stored for a longer period. It is possible, for example, to have a read-out of these

measurement data during maintenance schedules in order to detect slowly changing behavior in the wheel set shaft. An interface is used for this purpose, which enables a read-out either by radio/wireless or by cable.

In a further embodiment of the invention, the segment fields have no identical values, instead their values change gradually so that it is possible to establish exactly the location of the damage in the wheel set or on the disc. It is also possible to detect in which direction the wheel is turning. It is also conceivable that the distance between fields varies yet the field value remains the same. This results in somewhat varying waves, which nevertheless permit further detailed statements. It is also conceivable that further sensors such as temperature sensors are integrated in order to detect an increased temperature compared to the two sensors. This also enables the early detection of damage to a bearing .

Thus, two transducers are arranged on the rail-bound axle spaced axially or radially to each other and these have the rings radially enclosing the axle shaft with alternating fields showing different signal behavior, whereby the number of fields in the two rings is the same. Each of the two rings is assigned a measuring sensor, which supplies different output signals each time the two discs are distorted due to the torsional forces occurring (phase offsetting) , from which first and second square wave signals are formed, whereby the average torque is determined over a complete revolution of the rail-bound axle body from the flank distances of the first and second square wave signal. The binary information supplied by the two measuring sensors is converted into a corresponding electrical signal. A differential primary signal is formed from the two electrical signals of the individual strips, from which in turn a pulse sequence of voltage pulses is formed, whose height is fixed, but which is variable in width and whose data/measurement is the torque acting on the rail-bound axle.

Depending on the design of the rail-bound axle, different measuring sensors are used, but they are all used according to the measurement method described above.

An opto-electronic system for measuring torque and rotational speed of a rotating shaft uses two toothed discs, which twist against each other under torsion. A photocell and a

photodiode are arranged in front of and behind the toothed discs, respectively, in the shaft longitudinal direction. When the discs are twisted, the edges are misaligned. The length of time light is received by the photo transistor is dependent on the edge position and is thus a function of the torque. In an alternative embodiment of this measurement system, the light signal is sent to the strips with optically reflective and non-reflective zones.

Here as well, the twisting angle of the shaft changes the duration of reflection of the light signal between the strips, said signal being used as a torque-proportional signal. Similarly to the optical measurement of the twisting angle of the shaft, this angle is measured by means of two toothed discs or gear wheels and inductive pick-up sensors. The signal proportional to the torque is produced from the phase difference of the individual signals of the pick-up sensor. Naturally, the system can be used simultaneously for recording rotational speed.

Through the ongoing monitoring of the rail-bound axle by means of torque calculation and rotational speed recording, the current condition of the rail-bound axle is notified to the train driver/locomotive driver/tram driver/underground train driver. At the onset of wheel rim damage or the onset of axle damage, axle disc derailment, binding brakes, grinding brakes, these trigger a sudden change in torque and also a reduction in speed, which triggers an alarm to the operating and inspection staff. In contrast to strain gauges, the above method is very economic to retrofit on existing rail-bound axles.

Through this approach, a method is offered that, compared to the prior art, enables the range of application options to b extended as well as increasing accuracy.

Through this verification, a potentially serious accident involving travellers, inhabitants and collateral damage can be prevented by enabling early detection of material damage to rail vehicle wheel sets. Thus, derailed rail vehicle whee sets due to wheel rim cracks, bearing damage, binding brakes can be detected early and rectified.

Description of figures:

A brief description of the figures follows below:

Fig. 1 shows a wheel set shaft with two wheels and two alternative ways of attaching the sensors; Fig. 2 shows a recording and calculation of the square wave differential signal;

Fig. 3 shows a corresponding curve of the two signals and the differential signal;

Fig. 4a- 4c shows principles of different optical and inductive sensors;

Fig. 5 shows a lateral view of a wheel set roller bearing with a module housing attached externally for the control PCB;

Fig. 6 shows a sectional view of Fig. 5;

Fig. 7a shows radio communication between two sensors on an axle;

Fig. 7b shows a wagon with the axle from Fig. 7a;

Fig. 7c shows a train with the wagon from 7b.

Detailed description of the figures:

Figure 1 shows a rail vehicle wheel set 13 with a wheel set shaft 14 and two wheel discs 15. Two pairs of different sensors, for example, are arranged on this, the transducer of said sensors being arranged in different places. The

alternative arrangement should offer a comparison option. In practice, however, only one of the two arrangements is preferred. In the arrangement between the wheel discs, the measuring pick-up is normally arranged on the brake caliper if the wheel set shaft has internal disc brakes. In the second embodiment, there is an assembly on the housing of the shaft bearing. In an embodiment, the transducer 11 is arranged between the two wheel discs on the head of the wheel set shaft. In the alternative embodiment, the transducer 11 is arranged on the head of the wheel set shaft. Opto- electronic measuring sensors 12 measure the rotation of the transducer 11.

Fig. 2 and Fig. 3 show different signal behaviour in the flanks of the first square wave signals in relation to the flank of the second square wave signal, which is summed up each time and whose moment-free ratio is formed, which is determined from one or several full revolutions of the rail- bound axle loaded with the torque to be determined. The intervals Tmi + Tm + Ami + Am and the time t can be very accurately recorded by means of a counter with high

oscillator frequency.

The torque values, speed values, values from possible additional temperature sensors obtained are transmitted to a computer and shown visibly on the computer display and simultaneously transferred by GPS with GPRS module to a 2nd generation compact centre solution/Hi Path telecommunications facility. A commercial GPS module for locating e.g. lorries, cars and construction machinery could be used for this.

Figure 4a shows an optically-based torque measurement with toothed discs. An opto-electronic system for measuring torque and rotational speed of a rotating shaft uses two toothed discs, which twist against each other under torsion. A photocell and a photodiode are arranged in front of and behind the toothed disc, respectively, in the shaft axial direction. The length of time during which light is received by the photo transistor is dependent on the edge position and is therefore a function of the torque. Figure 4 b shows how a light signal in the measuring system is sent to strips with optically reflective and non- reflective zones. In this case as well, the twisting angle o the shaft between the strips causes a change in the duration of reflection, which can be used as a torque-proportional signal .

Figure 4c shows a toothed disc phase differential measurement of the twisting angle of the shaft by means of two toothed discs or gear wheels and inductive pick-ups. The torque- proportional signal is produced from the phase difference of the individual signals from the pick-up. Naturally, the system can simultaneously be used for rotational speed measurement .

Figure 5 shows a lateral view of a wheel set shaft bearing 51, with a corresponding cover 53, on which a part of the sensor 52 is attached. Normally, the power supply and the pick-up are arranged in the housing. The housing can be screwed onto an existing housing cover.

Figure 6 shows a sectional view of Figure 5. The sensor housing 68 includes batteries 69, a row of control PCBs 61, 62, 63, 64 and 65, which naturally could also be configured to be integrated. These control PCBs can be radio modules for the shortwave network or also GSM/UMTS modules for

communication with the exchange or GPS modules for position finding. Furthermore, a generator for power generation can be arranged on them. The transducer 67 is connected to the head of the wheel set shaft 70. The pick-up 62 records the signals of the transducer 67 through a hole 71. Normally, the sensor housing is screwed onto the shaft bearing housing. Figure 7a shows a schematic view of the radio module with recording of measured values and processing in the 2.4 GHz network. Optical scanning of the transducers 74, which are attached to a rail-bound axle 75, is carried out by the pickup 73. The data exchange between the sensors and a comparison unit is carried out via a 2.4 Ghz radio module 72, in order to conduct the comparison operators.

Figure 7b shows a railway wagon, tram wagon, underground train wagon 71 in schematic view, each of which have sensors 77 on both axles. Figure 7c then shows how this wagon 71 is integrated into a complete train and is connected to a head station 46, which carries out a data fusion and data

transmission and forms a user interface for the train conductor. GPS data can also be determined here. As a result of this information, there can be an automatic data link from the individual wagons to a rake/switch at the head station, which then in turn sends the data from the wagons involved back to the individual wagons in order to notify the

individual wagons which sensors are located in a train. This enables the construction of a suitable close-meshed network between the sensors. Through this central approach, which also contains decentralized concepts, it is possible for plausibility tests to be carried out and to enable sensor breakdown to be detected.

Claims

Rail vehicle wheel set, comprising a wheel set shaft with two wheel discs, comprising:

- at least two sensors, which are spaced from each other in an arrangement along the wheel set shaft, each including a transducer and a pick-up, of which one is arranged in a non-rotating manner and the other is arranged to rotate with the shaft;

the transducer being arranged annularly round the wheel set shaft or arranged on the end face of the wheel set shaft as a disc, and the transducer having radially arranged fields producing alternating signal behaviour; the pick-up detecting the alternating fields and producing a signal;

- a comparison unit that compares the signals of the two sensors with each other, and produces an alarm when the signals deviate by a preset threshold value.

Rail vehicle wheel set according to the previous claim, the transducer being rigidly arranged on the head or round the head of the wheel set shaft and rotating with this, and the pick-up being attached in or to the axle bearing housing, to detect the transducer.

3. Rail vehicle wheel set according to the previous claim, a housing of the pick-up being constructed in such a way that it can be attached in the existing axle bearing housing or can be screwed onto this. Rail vehicle wheel set according to any of the previous claims, the two sensors in the wheel set shaft

communicating via a radio module, the communication being directed to a central system in the wagon or in the train or to a stationary exchange and/or the communication takes places between the sensors of a common wheel set shaft and/or between the sensors of several wheel set shafts.

Rail vehicle wheel set according to the previous claim, the communication between several wheel set shafts communicating the occurrence of a curve and/or a point.

6. Rail vehicle wheel set according to the two previous claims, the identity of the sensor in the error case being communicated to the locomotive driver.

Rail vehicle wheel set according to any of the previous claims, the power supply being provided by batteries or by a generator that is driven by the rotation of the wheel set shaft.

Rail vehicle wheel set according to any of the previous claims, a temperature sensor and/or a GPS sensor and/or a centrifugal force sensor being additionally provided.

Rail vehicle wheel set according to any of the previous claims, a memory being provided that records sensor signals and makes these available via an interface.

Rail vehicle wheel set according to any of the previous claims, the sensors recording optically and/or

electromagnetically-

Rail vehicle wheel set according to any of the previous claims, number and size of fields of sensors being identical, or the size of fields varying in a known pattern in order to determine the position of an error or its wheel disc and/or to avoid a phase offset.

Method for recording damage to a rail vehicle wheel set, which comprises a wheel set shaft with two wheel discs, furthermore comprising at least two sensors, which are spaced from each other in an arrangement along the wheel set shaft, each comprising a transducer and a pick-up, of which one is arranged in a non- rotating manner and the other is arranged to rotate with the shaft, the transducer being arranged annularly round the wheel set shaft or arranged on the end face of the wheel set shaft as a disc, and the transducer having radially arranged fields producing alternating signal behaviour, the pick-up detecting the alternating fields and producing a signal, and a comparison unit including the steps:

-receiving the signals from the two sensors, comparing the two signals using the comparison unit;

- producing a warning if during the comparison a deviation is determined which lies above a preset threshold value, and produces an alarm when the signals deviate by a preset threshold value.

13. Method according to any of the previous method claims, at least a sensor sending its information by radio to the comparison unit.

Method according to the previous claim, each sensor being connected to a comparison unit, which also receives the data from the other sensor, in order to undertake the calculations redundantly.

Method according to any of the previous two claims, the communication being directed to a central system in the wagon or in the train or to a stationary exchange, in order to send information to the train conductor or to an inspection staff member.

Method according to the previous claim, the identity of the sensor in the error case being communicated to an inspection staff member

17. Method according to the previous four claims, the

communication between several wheel set shafts

communicating the occurrence of a curve and/or a point, so that biases in the measurement results resulting herefrom can be taken into account by the comparison unit .

18. Method according to any of the previous method claims, the power supply of the sensors and/or of the

comparison unit being produced by batteries or by a generator that is driven by the rotation of the wheel set shaft.

19. Method according to any of the previous method claims, a temperature sensor and/or a GPS sensor being

additionally provided, through which data are also transmitted. Method according to any of the previous method claims, a memory being provided in the sensor or in the comparison unit that records sensor signals and makes these available via an interface.

Method according to any of the previous claims, the sensors recording optically and/or electromagnetically

Method according to any of the previous claims, number and size of fields of sensors being the same and identical, or the size of fields varying in a known pattern in order to determine the position of an error or of the wheel disc and/or to detect a phase offset when calculating using the comparison unit.

Use of a device according to claim 1 to detect damage to a rail vehicle wheel set and/or the rail tracks.

Use of the device according to claim 23, characterized in that recording of wheel rim cracks, bearing damage, binding brakes, high temperatures and/or instability through fracture is recorded.