Test head probe for ultrasonic testing of wheel set shafts with an interior longitudinal borehole
Patent Information
- Authority / Receiving Office
- PL · PL
- Patent Type
- Patents
- Current Assignee / Owner
- DEUTSCHE BAHN AG
- Filing Date
- 2023-11-17
- Publication Date
- 2026-07-13
Abstract
Description
[0001] The invention relates to a test head probe for ultrasonic testing of wheelset shafts with internal longitudinal bores.
[0002] The wheelset axles of rail vehicles are regularly inspected for defects and inhomogeneities. Among other things, a test is carried out to determine whether there are any defects in the wheelset axle material. In particular, operational cracks can occur on the outer surface of the wheelset axle. These are detected using a probe equipped with angle beam probes, which is mounted in an inner bore of the wheelset axle and can move linearly along the longitudinal axis of the inner bore and can rotate about this longitudinal axis. By utilizing the well-known angle beam effect, inhomogeneities that are essentially oriented perpendicular to the test surface or the outer surface of the wheelset axle can be detected. This is essentially based on the test beam being reflected twice - namely by the outer surface of the wheelset axle opposite the test surface and by the inhomogeneity or inhomogeneity.at the crack itself - is reflected back toward the test head and is detectable there. The geometric offset between the beam axes of the transmitted and received test beams in a reference direction parallel to the longitudinal axis of the inner bore allows the location of the crack within the wheelset axle to be determined.
[0003] However, in surface-hardened axles, crack formation does not occur on the outer surface of the axle, but rather in its inner volume, usually directly beneath the surface-hardened zone. To detect such deep inhomogeneities, the so-called "tandem technique" is used according to the state of the art. This involves two spaced-apart angle-beam probes, each oriented at the same angle and in the same direction, with their acoustic axes in the same plane perpendicular to the test surface. A first probe is used for transmitting and the other probe for receiving. By varying the distance between the transmitting and receiving probes in a reference direction parallel to the longitudinal axis of the inner bore, inhomogeneities of different depths can be detected, provided they are oriented perpendicular to the test surface.This is particularly necessary in those areas of a wheelset axle where its outer diameter or cross-sectional area changes, such as at the cage arches in the transition area between a shaft seat and the shaft shank. In the context of this invention, these areas are referred to below as "transition areas". In such transition areas, the surface-hardened zone approximately follows the course of the cross-sectional transitions. Thus, the defects to be expected in the cross-sectional transitions are at different depths. As the depth of an expected defect increases, the distance between the test heads must be increased in a reference direction parallel to the longitudinal axis of the inner bore. For this purpose, the transmitting orThe receiving probes can be arranged within a probe carrier so that they can be displaced relative to one another in a direction parallel to the longitudinal axis of the inner bore, or a plurality of rigid receiving probes can be provided that are equally spaced from one another in this reference direction. In both cases, it is ensured that an ultrasonic signal transmitted for testing purposes and reflected by inhomogeneities at different depths actually hits a receiving probe.
[0004] However, if the cage arch is scanned in such transition areas, the lack of parallelism of the outer surface of the wheelset axle with respect to the longitudinal axis of the inner bore will result in reflections that cannot be detected in this probe configuration. Therefore, reliable detection and localization of inhomogeneities is not possible in such areas.
[0005] The invention is therefore based on the technical object of providing a test head probe for the ultrasonic testing of wheelset shafts with internal longitudinal bores, which overcomes this aforementioned disadvantage and improves the quality and reliability in the detection and localization of inhomogeneities in the area of cross-sectional transitions.
[0006] This is achieved according to the invention in that the probe comprises a plurality of probe supports arranged offset from one another by an intermediate angle with respect to a central longitudinal axis of the probe and simultaneously mounted so as to be rotatable about this central longitudinal axis, wherein each probe support is constructed from a transmitting probe and a plurality of receiving probes arranged along a longitudinal extension of the probe parallel to the central longitudinal axis of the wheelset shaft,wherein the transmitting probe of at least one first probe carrier is configured to emit a sound beam at an angle deflected in a mathematically positive sense with respect to a boundary surface normal at the sound exit point, and the transmitting probe of at least one second probe carrier is configured to emit a sound beam at an angle deflected in a mathematically negative sense with respect to the boundary surface normal at the sound exit point.
[0007] In the context of the invention, a "positive angle" is understood to mean an angle by which the beam axis (or axis of symmetry) of the sound beam is pivoted counterclockwise with respect to the direction of the interface normal at the sound exit point of the probe. Similarly, in the context of the invention, a "negative angle" is understood to mean an angle by which the beam axis of the sound beam is pivoted clockwise with respect to the direction of the interface normal at the sound exit point. In other words, these angles are given in radians. The probes are preferably designed as angle probes.
[0008] Such a probe according to the invention enables the sound beams to be projected into the same test zone of a wheelset axle with at least two sound beams with mutually opposite sound directions, without having to interrupt the test process to change the orientation of the probe within the wheelset axle. By rotating the probe according to the invention around the longitudinal axis of the inner bore, the transition area of a wheelset axle is continuously scanned by the sound beams of at least two probe carriers with mutually opposite sound directions during the same test process.Even if an inhomogeneity located in this transition area lies outside the detection range of the first probe due to its excessive depth, it will still be reliably detected by the second probe with an insonification direction opposite to that of the first probe. This allows the entire volume of a wheelset axle to be tested to be tested in a single, uninterrupted work pass. This not only speeds up the testing process but also increases its quality, as a potential source of errors or inaccuracies in the testing process is eliminated by eliminating the need to remove the testing fixture from the wheelset axle and then reinsert the fixture into the axle with its orientation reversed relative to the wheelset axle.
[0009] The invention particularly preferably provides that the probe comprises two probe supports arranged offset from each other by an intermediate angle of 180° with respect to the central longitudinal axis of the probe. Such a symmetrical arrangement with respect to the central longitudinal axis of the probe enables a uniform and unbalance-free rotation of the probe and facilitates the evaluation of the measurement signals acquired by the probes.
[0010] However, the invention is not limited to such a symmetrical arrangement of two probe carriers, but also extends to probe probes with any desired plurality of probe probes, which can be arranged with any desired and in particular also asymmetrical intermediate angles to one another, provided that at least two of the probe probes are set up by means of the aforementioned alignment of their probes to emit sound beams with mutually oppositely oriented sound directions into the same test zone of the wheelset axle.
[0011] According to one possible embodiment of the basic inventive concept, the probes of a probe carrier are combined into an array composed of a plurality of probes. An "array" is understood here as an arrangement of probes in which a plurality of probes are fixed to each other by means of a holder in a predefined relative geometric alignment. Such an array can enable higher testing speeds due to the rapid switching between multiple probe pairs.
[0012] The inventive concept further provides that the probe can be moved by means of a drive device configured to generate a helical or meandering movement of the probe around its central longitudinal axis, both axially along a longitudinal extension of the longitudinal bore and in a rotational direction over the inner surface of the longitudinal bore. For this purpose, the probe is mounted within the inner bore of a wheel set shaft during intended use, allowing it to be moved both axially along its central longitudinal axis and in a rotational direction around the central longitudinal axis. Such a drive device facilitates the automation of the application of the probe according to the invention.
[0013] The present invention is explained in more detail below using an exemplary embodiment and the accompanying drawings. They show: Figure 1 : schematic representation of the tandem test (state of the art); Figure 2 : schematic representation of the test with a test head probe according to the invention with a sound beam deflected by a positive angle; Figure 3 : schematic representation of the test with a test head probe according to the invention with a sound beam deflected by a negative angle.
[0014] The embodiment visualizes the testing of a surface-hardened wheelset shaft (10) by means of a test head probe (20) according to the invention inserted into the internally centered longitudinal bore (11) of the wheelset shaft (10).
[0015] In Figure 1First, the basic principle of tandem testing, known from the prior art, is visualized using the test of a surface-hardened wheelset axle. The test task consists in detecting any inhomogeneities (51, 52) in the form of material defects that occur in the boundary region between a hardened outer surface layer zone (15) of the wheelset axle and an unhardened inner region of the wheelset axle. This transition region between the surface layer zone (15) and the unhardened region of the wheelset axle (10) is schematically visualized in the figures of the exemplary embodiment using a dotted line (which, of course, does not exist in this form in reality).To perform the test, the probe (20) is inserted into an internal and internally centered longitudinal bore (11) of the wheelset shaft (10) and mounted therein in such a way that it can be displaced axially along its central longitudinal axis (A) and also rotated about this central longitudinal axis (A). According to the prior art known with regard to tandem testing, the probe (20) comprises a probe carrier (30), the sound beam emitted by the transmitting probe (31) of which, due to this axial and rotational mounting of the probe in the longitudinal bore (11) of the wheelset shaft (10), can cover the entire surface layer zone (15) and thus detect any inhomogeneities (51, 52) in the transition area to the surface layer zone (15).The sound beam emitted by the transmitting probe (31) is characterized by its acoustic axis (B), which is inclined relative to the test object or wheelset axle by the incidence angle (α) referred to the boundary surface normal (D) at the sound exit point (C). The incidence angle (α) is typically 35° to 55°. The sound beam undergoes a double reflection: first at the boundary surface closest to the irradiation (i.e., the outer surface of the wheelset axle (10) opposite the sound exit point (C)) and then at the inhomogeneity (51, 52). Depending on the depth (d 1 , d 2 ) of the respective inhomogeneity (51, 52), the thus reflected signal of the sound beam is received at one of the receiving probes (32...39) of the probe carrier (30).The maximum reception is to be expected at the receiving probe whose distance (relative to a direction parallel to the central longitudinal axis (A)) from the transmitting probe (31) has the smallest deviation from that according to the geometric relationship . a i = 2 * d i * tan α defined so-called "jump distance" (a 1 , a 2 ). This results, for example, in the detection of inhomogeneities in the depths (di ) between 10 mm and 35 mm (measured from the outer surface of the wheelset axle) at typical angles of incidence (α) between 35° and 55° and typical distances (ai ) between the transmitting probe and the receiving probes of a probe carrier between 20 mm and 70 mm. The probe (20) is located on the left side of the Figure 1 in a position detecting a first inhomogeneity (51) in a first depth position (d 1 ) and on the right side of the Figure 1in a position detecting a second inhomogeneity (52) in a second depth position (d 2 ).
[0016] The Figures 2 and 3 visualize the testing of a wheelset axle using a test head probe according to the invention, where Figure 2 the test head probe (20) in a first position and in Figure 3the test head probe is shown in a second position rotated by 180° around the central longitudinal axis (A) of the wheelset shaft (10). The wheelset shaft (10) has regions with different outer diameters; namely a shaft seat (12) and shaft shanks (13) adjoining it on both sides, wherein the outer diameter of the shaft seat (12) is larger than that of a shaft shank (13). The outer diameter of each shaft shank (13) is brought to the shaft seat (12) by means of a basket bend (14). In the spatial environment of such a basket bend (14) there are possible inhomogeneities (53, 54), each in the transition region between the hardened outer surface layer zone (15) and the inner region of the wheelset shaft (10), which is formed from the non-hardened base material of the wheelset shaft. The detection of inhomogeneities in this transition region is possible with the Figure 1However, this is not possible with the tandem testing device shown for the following reason: the test head probe (20) can be positioned relative to the wheelset axle (10) in a direction parallel to the central longitudinal axis (A) in such a way that the sound exit point of the transmitting angle-beam test head (31) is positioned in the region of the shaft seat (12), but the acoustic axis of the sound beam, which is inclined by an angle of incidence (α) with respect to the boundary surface normal, strikes the outer contour of the wheelset axle in the region of the basket arch (14). The sound beam thus strikes the first reflecting boundary surface in an area which is subject to strong cross-sectional changes and, in particular, is not parallel to the inner surface of the longitudinal bore provided for the sound coupling.
[0017] In contrast to the aforementioned prior art, the probe probe (20) according to the invention comprises, in addition to the first probe carrier (30), a further second probe carrier (40), wherein each probe carrier (30, 40) has a transmitting angle probe (31, 41) and a plurality of receiving angle probes (32, ...39; 42, ...49). All probes of each probe carrier are arranged directly adjacent to one another along a longitudinal extent of the probe carrier. In the exemplary embodiment, each probe carrier (30, 40) has eight receiving angle probes (32, ...39; 42, ...49). However, the invention is not limited by this, but can be implemented using probe carriers with any number of receiving probes. The second test head carrier (40) is arranged within the test head probe (20) with respect to the first test head carrier (30) in a position offset by 180° around the central longitudinal axis (A) of the test head probe (20).The invention is not restricted by this, but can also be implemented using a plurality of test head carriers with any desired, in particular asymmetrical, intermediate angles to one another. According to the embodiment shown as an example in the exemplary embodiment with two test head carriers (30, 40) offset from one another by an intermediate angle of 180° around the central longitudinal axis (A), a defined test area of the wheelset axle, e.g. the area of inhomogeneities (53, 54), is detected twice by the sound beam of a transmitting test head during a complete rotation of the test head probe (20) mounted in the longitudinal bore (11) of the wheelset axle (10) through 360°. This is the first time by the sound beam of the transmitting test head (31) of the first test head carrier (30) (as in the visualization of the test head probe (20) according to . Figure 2shown) and - after a rotation of the probe head (20) by 180° around the central longitudinal axis (A) - a second time through the sound beam of the transmitting probe (41) of the second probe head carrier (40) (as shown in the visualization of the probe head (20) according to Figure 3 shown).
[0018] While the acoustic axis (B 31 ) of the sound beam emitted by the transmitting probe (31) of the first probe carrier (30) - as explained above in the explanation of the prior art based on the Figure 1shown - is inclined by a first insonification angle (α) with respect to the wheelset axle which is mathematically positive with respect to the boundary surface normal (D 31 ) at the sound exit point (C 31 ), the acoustic axis (B 41 ) of the sound beam emitted by the transmitting test head (41) of the second test head carrier (40) is inclined by a second insonification angle (β) with respect to the wheelset axle which is mathematically negative with respect to the boundary surface normal (D 41 ) at the sound exit point (C 41 ). Thus, the area of the wheelset axle (10) to be tested is irradiated with sound beams from two mutually opposite directions during a single complete rotation of the test head probe (20) about the central longitudinal axis (A).
[0019] At the Figure 2In the view shown, the test head probe (20) is in such a relative first position with respect to the wheelset shaft (10) that the first test head carrier (30) with the first beam angle (α) deflected in the mathematically positive sense is closest to the area of the wheelset shaft (10) to be tested and the inhomogeneities (53, 54) are subject to beam irradiation at the first beam angle (α).
[0020] At the Figure 3In the view shown, however, the test head probe (20) is rotated by 180° about the central longitudinal axis (A) of the wheelset shaft (10) compared to the aforementioned first position and is in a relative second position with respect to the wheelset shaft (10) such that the second test head carrier (40) with the second beam angle (β) deflected in the mathematically negative sense is closest to the area of the wheelset shaft (10) to be tested and the inhomogeneities (53, 54) are subject to beam irradiation at the second beam angle (β).
[0021] The relative arrangement of the transmitting angle-beam probe (41) with respect to the receiving angle-beam probes (42...49) in the second probe carrier (40) is inverse or mirror-inverted to the respective relative arrangement of the transmitting angle-beam probe (31) and the receiving angle-beam probes (32...39) of the first probe carrier (30). While in the first probe carrier (30) the transmitting probe (31) is arranged in a first position in front of the receiving probes (32...39) with respect to a longitudinal direction of the probe carrier, this arrangement is diametrically opposite in the second probe carrier with respect to the same longitudinal direction; i.e. the transmitting probe (41) is in a last position after the receiving probes (42...49) with respect to the longitudinal direction of the probe carrier. This is necessary in order to ensure that the sound beam of the transmitting probe (41) is aligned in accordance with the Figure 1explained basic principle of the tandem test upon reflection at an outer surface of the wheelset axle acting as a boundary surface onto the arrangement of the receiving test heads (42...49). List of reference symbols:
[0022] 10Wheelset axle 11Longitudinal bore 12Shaft seat 13Shaft shank 14Basket arch 15Surface zone ACenter longitudinal axis of the wheelset axle 20Test head probe 30First test head carrier 31Transmitting angle beam probe of the first test head carrier αFirst angle of incidence B, B 31 , B 41Acoustic axis of the sound beam C, C 31 , C 41Sound exit point D, D 31 , D 41Interface normal at the sound exit point 32... 39Receiving angle beam probes of the first test head carrier 40Second test head carrier 41Transmitting angle beam probe of the second test head carrier βSecond angle of incidence 42...49Receiving angle beam probes of the second test head carrier 51... 54Inhomogeneity d 1 . d 2 Depth of an inhomogeneity a 1 , a 2 Jump distance between transmitting and receiving probe
Claims
1. Test head probe (20) for ultrasonic testing of wheelset shafts (10) with internal longitudinal bore (11), characterized in that the probe head (20) comprises a plurality of probe head supports (30, 40) which are arranged offset from one another by an intermediate angle with respect to a central longitudinal axis (A) of the probe head (20) and are simultaneously mounted rotatably about this central longitudinal axis (A), wherein each probe head support (30, 40) is constructed from a transmitting probe head (31, 41) and a plurality of receiving probe heads (32...39; 42...49) arranged along a longitudinal extension of the probe head (20) parallel to the central longitudinal axis (A), wherein the transmitting probe head (31) of at least one first probe head support (30) is arranged at a sound exit of a sound beam at an angle with respect to a boundary surface normal (D 31 ) at the sound exit point (C 31) in the mathematically positive sense and the transmitting probe (41) of at least one second probe carrier (40) is arranged to emit a sound beam at an angle (α) with respect to the boundary surface normal (D 41 ) at the sound exit point (C 41 ) in the mathematically negative sense deflected angle (β).
2. Test head probe according to claim 1, characterized in that the test head probe (20) comprises two test head supports (30, 40) arranged offset from one another by an intermediate angle of 180° with respect to the central longitudinal axis (A) of the test head probe (20).
3. Test head probe according to claim 1 or 2, characterized in that the probes of a probe carrier are combined to form an array consisting of a plurality of probes.
4. Test head probe according to one of claims 1 to 3, characterized in thatthe test head probe (20) is movable by means of a drive device designed to generate a helical or meandering movement of the test head probe (20) about its central longitudinal axis (A) both in the axial direction along a longitudinal extent of the longitudinal bore (11) and in the rotational direction over the inner surface of the longitudinal bore (11).