DE10052045A1 - Device and method for testing a railway wheel - Google Patents

Abstract

A device and a method for testing a railroad wheel with a tread that lies on the running surface of a rail and rolls on it are described. DOLLAR A The invention is characterized in that in the area of the running surface within the rail, a plurality of test heads emitting and receiving ultrasonic waves are arranged in the manner of a linear array along the rail in such a way that each individual test head when the railroad wheel rolls over the ultrasonic waves through the Coupling the tread into the railroad wheel and receiving ultrasound waves reflected back inside the railroad wheel, and that the test heads are arranged obliquely inclined to the longitudinal direction of the rail within the rail and enclose an angle 0 ° <gamma <90 ° with the longitudinal axis of the rail.

Description

Technical field

The invention relates to an apparatus and a method for testing a railway wheel with a tread on the running surface of a rail rests and rolls on it.

State of the art

Non-destructive material testing, especially in the field of Safety technology for railways is a specialty that is important  has gained considerably, not least due to events such as Train accidents that can be traced back to failure of wheels, for example.

Especially for quality control of new and inspection checks by in Railway wheels in operation are touring a number of Examination procedure known.

So the railway wheels of railway trains have to be in certain time intervals non-destructive testing for errors, especially cracks or breakouts, be subjected. The cracks can be caused by, among other things Material fatigue due to thermal stress due to braking and by deformation processes due to the pressure load. To wheel breaks and to preclude any fatal consequential damage that may arise, is the recurring inspection at short intervals, e.g. B. every three to five days, required. The non-destructive testing must be quick, i. H. for one entire train in about an hour.

DE 42 20 444 A1 describes a method for longitudinal, transverse and Oblique error testing by means of ultrasound of workpieces after the pulse echo Process known. The workpiece is rotated and an ultrasonic wave coupled into the workpiece with a circular movement of the direction of insonification.

A device for ultrasound testing is known from US Pat. No. 5,349,861 known from railway wheels, with the help of which ultrasound through an end face of the Wheel rim can be coupled into the railroad wheel. Another device for Testing of railway wheels is described in WO 90/13814. This Device has ultrasound transducers designed as rolling elements, which during rolling motion of the railroad wheel on it. With help of a Tread sensor is ultrasound through the tread in the railroad wheel can be coupled in, and with the aid of a wheel flange sensor, ultrasound can be inserted into the wheel rim einschallbar. The devices described in the two documents for Testing railway wheels can only be a limited number possible Detect crack positions and crack orientations in the railway wheel.  

At the Internet address http: / / www.ndt.net/article/report/df97/hintze/hintze_d.htm became a technical article by H. Hintze, Deutsche Bahn, on June 10, 1998 at 10:13 a.m. AG, published in which a method for ultrasonic testing of railway wheels with With the help of surface waves, so-called Rayleigh waves, is described. there is using an electrodynamic converter based on permanent magnets (so-called EMUS, which stands for electromagnetic ultrasonic transducer) one Ultrasonic surface wave generated in the wheel material. The surface wave is coupled through the tread and spreads starting from the transducer on both sides in a near-surface area along the tread of the wheel. After a complete orbit around the wheel, the Rayleigh waves from one received another electrodynamic converter again. The electrodynamic Transducers are - spaced in the direction of travel of the train - in the rails built-in. The railroad train rolls over the converter at low speed time.

With this test technique, only the tread of the railway wheel can be tested capture, but not an inner circumferential surface of the railway wheel or the area around the wheel hub. Another disadvantage of this technique is that the Penetration depth of the Rayleigh wave is small (a few millimeters), so that cracks with shallow depths from those with greater depths are distinguishable. Another serious disadvantage of this test technique is that justifies that the wear on the wheel tread due to increased Sound attenuation has a great influence on the spreading capacity of the Has Rayleigh wave. It follows from this that this testing technique on new bikes very much works well with older bikes, especially with a mileage of several 10,000 km, especially for railway wheels, where more with the Crack formation is to be expected, but is no longer meaningful and therefore failed.

The Internet address http: / / www.ndt.net/article/0698/salzb/salzb.htm was published on June 10, 1998 at 10:10 a report on a lecture at the annual meeting of the  German Society for Non-Destructive Materials Testing in Lindau from 13th to May 15, 1996, held by H.-J. Salzburger and H. Hintze, published. In this Conference report is an impulse echo test method for the detection of a crack in one Railroad wheel described, with the front of the railroad wheel with linearly polarized transverse waves radiated perpendicular to the face becomes.

With this test method, the sound attenuation is polarized from across to the crack Exploited waves. So polarized ultrasonic waves have to be generated, why as with the first test method electromagnetically working Ultrasonic transducers (EMUS) are necessary. These so-called EMUS converters work with the current state of the art for crack testing on railway wheels not sufficiently reliable.

In the latter test method, the railway wheel is placed on a roller block with the help of a drive wheel and the EMUS converter is turned in the radial direction emotional. The test method has the additional disadvantage that a possible crack in the essential only with a radial orientation, e.g. B. with vertical alignment with respect to the running direction of the tread is detectable.

Presentation of the invention

The invention has for its object a rotating test specimen, in particular a railway wheel, to be checked in such a way that cracks in larger numbers expected positions and orientations more reliably and faster than with the known test methods are detectable. The invention is therefore the The task is based on a method and a device for this purpose specify.

The object underlying the invention is achieved in claim 1 specified. A method according to the invention is the subject of claim 16. Features which advantageously further develop the inventive idea are  Subclaims and the description, in particular with reference to the To see embodiments.

According to the invention is a device for testing a railway wheel with a Tread that rests on the running surface of a rail and rolls on it, further developed in that in the area of the running surface within the rail Variety of probe heads emitting and receiving ultrasonic waves Linear arrays are arranged along the rail so that each one Test head when rolling over the railway wheel with ultrasonic waves through the tread couples into the railroad wheel as well as within the railroad wheel receives reflected ultrasonic waves, and that the probes are Rail longitudinal direction are arranged inclined and inclined within the rail form an angle of 0 ° <γ <90 ° with the longitudinal axis of the rail.

The test heads, which are designed as immersion technology test heads, point to Ultrasonic generation each have at least one piezo element and are in one linear array arranged in a, filled with coupling agent, groove within the Rail is attached, wherein the array length is preferably at least equal to that Corresponds to the scope of the wheel to be tested. There are also position detectors provided the position of the wheel relative to the test head array path as well as the Determine speed.

The inventive method for testing a railway wheel with a Tread which rests on the running surface of a rail and rolls on it, and the use of the device according to the invention provides for this from that ultrasonic waves from the side of the rail in the railroad wheel be coupled while the railroad wheel is inside the rail integrated test heads that at least within the railway wheel some of the injected ultrasound waves are reflected back by the Probes are received from which the ultrasonic waves have been emitted are that a position detection of the railway wheel is carried out and that in an evaluation unit together with the determined position data  Measuring signals from the test heads for error detection within the railway wheel be used.

Brief description of the invention

The invention is hereinafter described without limitation of the general The inventive concept based on exemplary embodiments with reference to the Drawing described as an example. Show it:

Fig. 1 a perspective view of a railway rail with integrated in a groove probes (probe array), and designed as a rail-wheel test piece during rolling on the rail,

Fig. 2 cross section through Fig. 1 from the area of the point of contact between the wheel and rail and

Fig. 3 three sections (Q) through alternative embodiments.

Ways of carrying out the Invention, Industrial Usability

Fig. 1 shows a railway wheel 1 during the rolling of the tread 2 on the traveling surface 3 a rail 4. A number m of immersion technology probes 6 in the form of a linear array is integrated into a groove 5 . The number m is the quotient of the wheel circumference and the minimum possible distance between two adjacent test heads. With a typical railway wheel diameter of 900 mm and a minimum probe distance of approx. 14 mm, m = 200 probes result. A subgroup 7 of the linear probe array chain is excited via an angle of attack γ in such a way that an ultrasonic wave 9 is irradiated into the wheel 1 at the angle of incidence α, so that errors in the volume 10 and starting from the tread 11 - in the case of wheel tires also from the inner one Bore surface 12 - can be sonicated and reflect the ultrasound back towards the sub-group.

The diving technology test heads of subgroup 7 receive the reflected ultrasound and feed the measurement signals to a control and evaluation circuit 13 .

Via a position detection device consisting, for. B. from light barriers 14 and a mirror 14 a, the position of the wheel with respect to the starting position of the linear probe array and the lateral speed of the wheel is determined and also fed to the control and evaluation circuit.

The individual immersion technology probes 6 are inclined in the longitudinal direction of the rail at an angle γ (see also FIG. 2), so that the ultrasound waves are irradiated obliquely into the wheel at an angle of incidence of 0 ° <α ≦ 90 ° as transverse and / or longitudinal waves. If the angle γ is chosen to be 0 °, there is also vertical exposure of longitudinal waves.

The variable insonification angle α is achieved in that, in addition to the test head P _N , which sounds precisely at the contact point (P _up ) of the wheel 1 , the test heads (P _N-1 , P _N-2 , P _N-3 ,... P _Nn , where n depends on the diameter of the wheel, are activated. The probes (P _N-1 , P _N-2 , P _N-3 , _... P _Nn ) _relate to those probes that correspond to the contact point (P _followed) in the direction of movement of the wheel 1. Due to the curvature of the wheel 1, the angle of incidence changes β at the interface coupling means / wheel surface in all further activated probes, and also the angle of incidence α of the turned echoed in the wheel transverse wave or longitudinal wave changes this. The arrangement simulates a piezoelectric phased array without a complex phase delay.

This pivoting of the sound beam, which is forced by the wheel geometry, can be used to detect defects in the entire volume of the wheel rim, on the tread, on the inside of the wheel in the case of tire tires and in the disc of solid tires. While the wheel 1 moves over the rail 4 , one test head is switched off and a new one is switched on, controlled by the signals from the existing position detectors. Through this procedure and by means of a multiplexer, the ultrasonic testing device can manage with a number of channels of (n + 1). In typical single track bikes with diameters of approx. 900 mm, n is approx. 3.

As mentioned above, the test heads of the linear test head array are accommodated in a groove-shaped recess 5 in the rail 4 filled with coupling agent and are protected from mechanical wear by a sufficient distance between the test head 6 and the wheel surface. The position of the test body 6 and thus the position of the test heads relative to the test body can be determined with an optical position detection device, the output signals of which are stored in the control and evaluation circuit together with the measurement signals received by the test heads, so that starting from a reference position after the execution of the Faulty locations in the test specimen can be located.

With the help of the position data and the lateral wheel speed, when the wheel rolls on the rail, a subset of the test head elements is activated in such a way that the first test head P _N , sounds directly at the contact point of the wheel on the rail and the other test heads P _N-1 bis P _Nn , also sound in the direction of the wheel surface at the necessary cycle speed, with one test head being switched off and another test head being switched on depending on the lateral speed.

The longitudinal section shown in FIG. 2 from the area of the contact points between wheel and rail shows 8 of the m test heads 6 , a subgroup 7 of four test heads with the test head numbers P _N , P _N-1 , P _N-2 , P _N-3 longitudinal Ultrasound waves penetrate at an angle of attack γ in the direction of the wheel surface. The natural curvature of the wheel (wheel radius R) creates an insonification angle α, which increases with increasing n and thus allows the sound beam to be swiveled without using an electronic time delay.

FIG. 3a shows a cross section Q through the section in FIG. 1. A groove 5 in the rail 4 and a diving technology test head 6 can be seen , which penetrates into the wheel rim of the wheel 1 . The sound is carried out parallel to the z-axis. The groove 5 is filled with coupling agent.

FIG. 3b also shows a cross section Q through the cut in Fig. 1. In contrast to FIG. 3a are now two probes 15 at a distance (y _0, y ₁₎ to the pitch circle at y = 0 located. The test heads 15 sound at an insonification angle α and additionally at a squint angle δ in the direction of the inner and outer wheel rim end faces 16 in order to detect defects in the area 17 .

FIG. 3c likewise shows a cross section Q through the section in FIG. 1. In contrast to FIG. 3b, the test heads 15 are now exposed at a squint angle δ in such a way that defects in the areas 18 (inner and outer end face) can be detected.

LIST OF REFERENCE NUMBERS

1

railway wheel

2

tread

3

driving surface

4

rail

5

groove

6

Test head, immersion technology test head

7

Subset of probes

8th

Not awarded

9

ultrasonic wave

10

volume

11

tread

12

bore surface

13

evaluation

14

light barriers

14

a mirror

15

probes

16

Radkranzstirnfläche

17

.

18

Area

Claims (17)

1. Device for testing a railroad wheel with a tread which rests on and rolls on the running surface of a rail,
characterized by
that in the area of the running surface within the rail, a plurality of test heads emitting and receiving ultrasonic waves are arranged in the manner of a linear array along the rail such that each individual test head couples ultrasonic waves through the tread into the railroad wheel as well as within the railroad wheel when the railroad wheel is rolled over receives reflected ultrasound waves, and
that the test heads are arranged obliquely inclined to the longitudinal direction of the rail within the rail and enclose an angle of 0 ° <γ <90 ° with the longitudinal axis of the rail. 2. Device according to claim 1, characterized in that the test head is a diving technology test head which at least one piezo element generating and receiving ultrasonic waves having. 3. Device according to claim 1 or 2, characterized in that a groove-shaped in the running surface of the rail Recess is provided in which the plurality of test heads are introduced. 4. Device according to one of claims 1 to 3, characterized in that between the tread and the probes Coupling means for coupling and uncoupling the ultrasonic waves is provided. 5. The device according to claim 3 or 4, characterized in that within the groove-shaped recess for the Coupling means suitable for coupling and uncoupling the ultrasonic waves is provided,  that the test heads at least completely on their side facing the driving surface encloses. 6. The device according to claim 4 or 5, characterized in that the coupling agent is water and / or alcohol or fluid containing gel. 7. Device according to one of claims 4 to 6, characterized in that the coupling means is flush with the running surface of the rail is. 8. Device according to one of claims 1 to 7, characterized in that the linear array of probes at least has a length along the rail, which is the circumferential length of the tread of the Railway wheel corresponds. 9. Device according to one of claims 1 to 8, characterized in that y is selected such that in a point of contact between the tread and the running surface perpendicularly above a test head P _N , the so-called contact point, the ultrasonic waves emerging from this test head P _N Couple transverse and / or longitudinal ultrasonic waves with an insonification angle α with 0 ° <α ≦ 90 °, measured from the normal to the point of contact, into the railway wheel. 10. The device according to claim 10, characterized in that the test heads are arranged adjacent to one another in the longitudinal direction to the rail such that n, in a linear sequence to the test head P _N, adjacent test heads couple ultrasonic waves into the railroad wheel with angles α _n different from the angle α. 11. The device according to claim 10, characterized in that n is the diameter of the railway wheel, that with a diameter of approx. 900 mm n is 3 or 4. 12. The device according to one of claims 1 to 11,
characterized in that a control device is provided which individually activates the test heads,
that a detection unit detecting the position of the railroad wheel is provided, and
that an evaluation unit is provided to which the measurement signals received by the test heads can be fed together with the position data for testing and localizing faulty locations in the railway wheel. 13. The apparatus according to claim 12, characterized in that the detection unit is an optical Position detection device is. 14. The device according to one of claims 1 to 13, characterized in that the test heads in pairs side by side within of the rail and inclined to the normal of the running surface by an angle δ, the so-called squint angles are arranged. 15. A method for testing a railway wheel with a tread which rests on the running surface of a rail and rolls on it, using the device according to one of claims 1 to 14,
characterized,
that ultrasonic waves are coupled into the railroad wheel from the side of the rail while the railroad wheel is rolling over the test heads integrated into the rail,
that the injected ultrasound waves are at least partially reflected back within the railroad wheel and received by the test heads from which the ultrasound waves were emitted,
that a position detection of the railway wheel is carried out and
that in an evaluation unit, together with the determined position data, the measurement signals of the test heads are used for error determination within the railway wheel. 16. The method according to claim 15, characterized in that in each case n test heads arranged in immediate succession are activated to the test head P _N which lies below the contact point between the running surface and the running surface. 17. The method according to claim 16, characterized in that the respective n test heads, which connect to the test head P _N in the direction of travel of the wheel, are activated.