Ultrasonic inspection of an axle

A method and system for ultrasonic inspection of an axle is disclosed. An ultrasonic probe and wedge are placed on the radial surface of an outboard journal of the axle and an ultrasonic scan is directed toward the inboard journal, wherein the devices mounted on the inboard journal remain mounted during the ultrasonic scan.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to a method and system for ultrasonic inspection of an axle.

Nondestructive testing devices can be used to inspect test objects to detect and analyze anomalies in the objects. Nondestructive testing typically involves placing one or more probes on the surface of the test object in order to perform testing of the underlying structure. One method of nondestructive testing employs ultrasonic signals.

Generally, an ultrasonic testing system includes an ultrasonic probe for transmitting and receiving ultrasonic acoustic waves to and from a test object, and a probe cable for connecting the ultrasonic probe to an ultrasonic test unit that includes a display for viewing the test results. In an ultrasonic testing system, electrical pulses are fed from the ultrasonic test unit to an ultrasonic probe where they are transformed into acoustic pulses by one or more ultrasonic transducers (e.g., piezoelectric elements) in the ultrasonic probe. During operation, electrical pulses are applied to the electrodes of one or more ultrasonic transducers, thus generating ultrasonic acoustic waves that are transmitted to the test object to which the probe is coupled. Conversely, when an ultrasonic acoustic wave is reflected from the test object and contacts the surface of the ultrasonic transducer(s), it causes the transducer(s) to vibrate, generating a voltage that is detected as a receive signal by the ultrasonic test unit. As the ultrasonic acoustic waves pass through the test object, various reflections, called echoes, occur as the ultrasonic acoustic wave interacts with anomalies within the test object.

When testing with a single element probe, the echo signals are typically displayed on the screen of the ultrasonic test unit as an A-scan trace with echo amplitudes appearing as vertical deflections of the trace and time of flight or distance information displayed on the horizontal axis along the trace. This single element probe is often mounted on a wedge to direct the sound at a desired angle to inspect different regions of the test object. In order to inspect the full volume of the object, it may be necessary to scan the object several times using different angled wedges, which can be time consuming.

Another type of ultrasonic probe, a phased array ultrasonic probe, has a plurality of electrically and acoustically independent ultrasonic transducers mounted in a single housing. By varying the timing of the electrical pulses applied to the ultrasonic transducers, a phased array ultrasonic probe can generate ultrasonic beams at different angles, allowing the phased array ultrasonic probe to steer the ultrasonic beam at different angles through the test object to try to detect anomalies using a single wedge. The ultrasonic waves received at the various angles can be processed to produce a sector scan (or S-scan) image of the test object, allowing visual identification of any anomalies, eliminating the need to rescan the test object several times with different wedges on a single element probe. The S-scan provides a two-dimensional view of all amplitude and depth data from all of the transducers of the phased array probe corrected for the delay and the refracted angle.

Ultrasonic probes are used to inspect axles of, e.g., railway cars. A typical rail axle will include seats for mounting rotating devices involved in the operation of the railway car, including wheels. The inboard journal of the rail axle located between the wheels typically includes one or more gears, brake discs, and a cover for protecting the axle. These devices located on the inboard journal of the rail axle make ultrasonic inspection of the inboard journal by placing one or more ultrasonic probes on the inboard journal difficult and time consuming. For example, the cover of the inboard journal must be removed or otherwise disassembled to provide access to the rail axle to place the ultrasonic probe in contact with the inboard journal.

BRIEF DESCRIPTION OF THE INVENTION

A method and system for ultrasonic inspection of an axle is disclosed. An ultrasonic probe and wedge are placed on the radial surface of an outboard journal of the axle and an ultrasonic scan is directed toward the inboard journal, wherein the devices mounted on the inboard journal remain mounted during the ultrasonic scan. An advantage that may be realized in the practice of some disclosed embodiments of the method and system for ultrasonic inspection of an axle is that removal or disassembly of devices on the inboard journal of the axle is not required, simplifying and reducing the time required to conduct the inspection.

In one embodiment, a method for ultrasonic inspection of an axle is disclosed, wherein the axle comprises a longitudinal axis and an inboard journal between a first outboard journal and a second outboard journal, and wherein a plurality of devices are mounted on the inboard journal. The method comprises the steps of placing a first ultrasonic probe and a first ultrasonic wedge at a first location on a radial surface of the first outboard journal, wherein the radial surface is substantially parallel to the longitudinal axis of the axle, and performing a first ultrasonic scan directed to the inboard journal, wherein the plurality of devices mounted on the inboard journal remain mounted during the first ultrasonic scan.

In another embodiment, a system for ultrasonic inspection of an axle is disclosed, wherein the axle comprises a longitudinal axis and an inboard journal between a first outboard journal and a second outboard journal, and wherein a plurality of devices are mounted on the inboard journal. The system comprises an ultrasonic inspection station comprising a display, a microprocessor, a memory coupled to the microprocessor, and one or more executable instructions stored in the memory and configured to be executed by the processor, a first ultrasonic probe and a first ultrasonic wedge at a first location on a radial surface of the first outboard journal, wherein the radial surface is substantially parallel to the longitudinal axis of the axle, and a first probe cable connecting the first ultrasonic probe to the ultrasonic inspection station, wherein the first ultrasonic probe and the first ultrasonic wedge are configured to perform a first ultrasonic scan directed to the inboard journal, and wherein the plurality of devices mounted on the inboard journal remain mounted during the first ultrasonic scan.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2are block diagrams of an exemplary ultrasonic testing system100for inspecting an axle3.FIG. 1is an enlarged view of the first (left) end1of the axle3.FIG. 2shows the entire axle3(first end1and second (right) end2) and an exemplary inspection stand600. To illustrate the exemplary ultrasonic testing system100, an exemplary axle3(e.g., a rail axle) is illustrated. It will be understood that the exemplary ultrasonic testing system100can be used with a variety of axles of different configurations.

The exemplary axle3includes a first (left) outboard journal10and a second (right) outboard journal50axially opposite of the first outboard journal10, with an inboard journal20extending between the first outboard journal10and the second outboard journal50. The first outboard journal10has a distal (first) end11and a proximal (second) end12. The first end face8of the distal end11of the first outboard journal10can include a first end face opening9(e.g., counter sink or hollow shaft) extending through a portion of the first outboard journal10for mounting equipment. As shown inFIG. 1, the first outboard journal10may include multiple sections having different diameters with one or more steps14between the different sections. For example, a first end face step14can be located between the first end face8and the main portion13of the first outboard journal10.

The inboard journal20of the axle3has a first end21proximate to the first outboard journal10and a second end22proximate to the second outboard journal50. The axle3can include a first (left) wheel seat24for mounting a first (left) wheel34between the first outboard journal10and the inboard journal20, and a second (right) wheel seat64for mounting a second (right) wheel74between the second outboard journal50and the inboard journal20. The inboard journal20can also include a first (left) gear seat26for mounting a first (left) gear36and a second (right) gear seat66for mounting a second (right) gear76. The inboard journal20can also include a brake disk seat28for mounting a brake disk38. The inboard journal20may also include a cover (or cuff or sheath)40would need to be removed or otherwise disassembled to access the inboard journal20. The first outboard journal10of the exemplary axle3also includes a curved step18between the main portion13and a dust (or water) guard seat19.

The axle3is shown with various anomalies, including a first wheel seat anomaly23, a first gear seat anomaly25, a brake disk seat anomaly27, and an inboard journal anomaly29. An ultrasonic testing system100can be employed to detect the presence of these anomalies23,25,27,29.

The ultrasonic testing system100can comprise a first probe110mounted on a first ultrasonic wedge114and a second probe210mounted on a second ultrasonic wedge214. It will be understood that the probe and a wedge can be provided as separate components or integrated into a single device. The first and second ultrasonic probes110,210include a transducer element (for a single element ultrasonic probe) or transducer array (for a phased array ultrasonic probe)112,212. The first and second ultrasonic wedges114,214can be made from any material that has an acoustic velocity different from that of the axle3. For example, some ultrasonic wedges are made from plastics such as plexi-glass or a polystyrene material through which sound travels at a known velocity. In one embodiment, the first ultrasonic wedge114is located on the radial surface16(i.e., surface substantially parallel to the longitudinal axis5of the axle3) of the first outboard journal10at a first ultrasonic wedge location15proximate to the distal end11of the first outboard journal10, while a second ultrasonic wedge214is located on the radial surface16of the first outboard journal10at a second ultrasonic wedge location17proximate to the proximal end12of the first outboard journal10. As shown inFIG. 2, the ultrasonic testing system100can also comprise a third ultrasonic probe310and a fourth ultrasonic probe410(and related devices (e.g., transducer array and ultrasonic wedges)) located on the radial surface56of the second outboard journal50. While, for simplicity, the discussion of the ultrasonic testing system100focuses on the first and second ultrasonic probes110,210located on the first outboard journal10, it will be understood that the same discussion also applies to the third and fourth ultrasonic probes310,410located on the second outboard journal50.

One or more probe cables111,121can connect the first and second ultrasonic probes110,210to an ultrasonic inspection station500, which can include one or more microprocessor(s)510for running system software and controlling system operations, and memory520coupled to the microprocessor510. Computer program instructions (executable instructions) can be stored in memory520or available to be executed by the microprocessor510(e.g., downloadable from a network) can make up all or a portion of the software and software packages discussed herein. The ultrasonic inspection station500can also include a power supply540, connected to an external power supply (e.g., AC voltage between 90V and 240V) or provided by rechargeable batteries. The ultrasonic inspection station500can also include peripheral interfaces430for managing data being sent between the ultrasonic inspection station500and other components. For example, in one embodiment, the peripheral interfaces430can include a USB, Ethernet (LAN), or wireless interface (WLAN) for receiving and loading an inspection plan.

The ultrasonic inspection station500can also comprise a display550for viewing system operations and inspection results. Electronics in the ultrasonic inspection station500can transmit and receive ultrasonic signals. The received signals are typically processed through some type of analog to digital conversion, after which they are displayed as A-scans with amplitude on the y axis and time of flight on the x axis (for single element ultrasonic probes) or displayed as sector scans (for phased array ultrasonic probes). These digital signals form the signature of a potential anomaly and are typically stored in memory520and post processed to provide additional views for the operator to assist in determining if an anomaly is truly a defect or not. The microprocessor510can provide control over the entire process.

In one embodiment and as shown inFIG. 2, the ultrasonic probes110,210,310,410and the ultrasonic inspection station500can be part of an inspection stand600that includes a conventional roll stand610and a plurality (e.g., four) independently controlled ultrasonic probe manipulators611,612,613,614for placing the ultrasonic probes110,210,310,410onto the axle3. The wheels34,74of the axle3can be rotated by the roll stand610to provide a 360 degree ultrasonic scan of the axle3by the ultrasonic probes110,210,310,410located on the outboard journals10,50. In another embodiment, axle3remains stationary while the ultrasonic probes110,210,310,410are rotated around the axle3using the ultrasonic probe manipulators611,612,613,614.

As discussed previously, it is desirable to be able to perform an ultrasonic inspection of the inboard journal20of the axle3without having to remove or otherwise disassemble any of the devices mounted on the inboard journal20, including the wheels34,74, gears36,76, brake disk38, or cover40. In one embodiment and as shown inFIG. 1, the first ultrasonic probe110and the second ultrasonic probe210can be phased array ultrasonic probes including ultrasonic transducer arrays112,212. It will be understood that other transducers (e.g., two-dimensional arrays and single elements) and wedges (different angles (e.g., in the range of thirty six degrees to forty four degrees) and materials) can be used. It will also be understood that, for clarity, whileFIG. 1only shows the ultrasonic inspection of the first end1of the axle3using ultrasonic probes110,210located on the first outboard journal10, additional ultrasonic probes can be located on the second outboard journal50for ultrasonic inspection of the entire axle3. It will be further understood that in some embodiments, a single ultrasonic probe and ultrasonic wedge can be used in multiple locations on the axle3(rather than a plurality of probes110,120and wedges114,214simultaneously positioned at different locations along the axle3). For example, a single phase array ultrasonic probe and ultrasonic wedge can be used in a single location on the first outboard journal10providing sufficient coverage of the first end1of the axle3from that one location and then relocated to the second outboard journal50to provide sufficient coverage of the second end2of the axle3from one location. Additionally, a single phase array ultrasonic probe and ultrasonic wedge can be used at a first location on the first outboard journal10and the moved to a second location on the first outboard journal10. The single phase array ultrasonic probe and ultrasonic wedge can be slid axially from the first location to the second location. In the case where a single element ultrasonic probe is used with an ultrasonic wedge at a first location, the ultrasonic wedge can be changed several times to perform a complete scan of the axle from that first location.

Returning toFIG. 1, to conduct an ultrasonic inspection of the axle3, the first ultrasonic wedge114and the second ultrasonic wedge214are located on the radial surface16of the main portion13of the first outboard journal10. Locating the inspection devices on the first outboard journal10avoids having to remove or otherwise disassemble the cover40or any other devices to access the inboard journal20to place the ultrasonic wedges114,214on the axle3. Locating the inspection devices on the radial surface16of the first outboard journal10rather than the first end face8avoids having to compensate for or avoid engravings or other disruptions typically found on the first end face8of the axle3that can distort the ultrasonic inspection.

In the exemplary embodiment illustrated inFIG. 1, the material and angle of the first ultrasonic wedge114is chosen to provide a first incident ultrasonic beam120directed towards the inboard journal20that will produce a first ultrasonic beam sector scan123of the inboard journal20of the axle3. The first ultrasonic beam sector scan123covers the range from a lower first refracted ultrasonic beam121(at a lower first refracted ultrasonic beam angle131) to an upper first refracted ultrasonic beam122(at an upper first refracted ultrasonic beam angle132). Similarly, the material and angle of the second ultrasonic wedge214is chosen to provide a second incident ultrasonic beam220directed towards the inboard journal20that will produce a second ultrasonic beam sector scan223of the inboard journal20of the axle3. The second ultrasonic beam sector scan223covers the range from a lower second refracted ultrasonic beam221(at a lower second refracted ultrasonic beam angle231) to an upper second refracted ultrasonic beam222(at an upper second refracted ultrasonic beam angle232).

In one embodiment, the first ultrasonic probe110and the second ultrasonic probe210can be phased array ultrasonic probes including the same ultrasonic transducer arrays112,212(e.g.,16element, 2.25 MHz, linear phased array with 1.0 mm pitch). The ultrasonic wedges114,214can be forty one degree wedges made of a cross linked polystyrene microwave plastic (REXOLITE). This combination (of the probe and wedge) can provide first and second ultrasonic beam sector scans123,223within the range between a lower refracted ultrasonic beam angle131,231of approximately forty degrees and an upper refracted ultrasonic beam angle132,232of approximately eighty degrees to provide sufficient coverage to identify anomalies on the inboard journal as far as 75.0 cm or more away from the first end face8. The ultrasonic beam sector scans123,223can be performed at angular increments from 0.5 to 2.0 degrees. In the exemplary embodiment, the first ultrasonic probe110and transducer112are the same as the second ultrasonic probe210and transducer212, and the first ultrasonic wedge114is the same as the second ultrasonic wedge214, producing ultrasonic scans with the same parameters. In other embodiments, the first ultrasonic probe110, transducer112, and wedge114may be different from the second ultrasonic probe210, transducer212, and wedge214.

In one embodiment, the first ultrasonic wedge location15on the radial surface16surface of the main portion13of the first outboard journal10can be determined by placing the first ultrasonic wedge114on the distal end11of the first outboard journal10as close to the first end face8without having the first ultrasonic beam sector scan123affected by the first end face opening9extending through a portion of the first outboard journal10or any first end face step14that may exist. Locating the first ultrasonic probe110and the first ultrasonic wedge114at the first ultrasonic wedge location15maximizes the coverage of the first ultrasonic beam sector scan123of the first outboard journal10and the first end21of the inboard journal22. As can be seen inFIG. 1, the first ultrasonic beam sector scan123provides coverage from before the dust guard seat19well into the inboard journal beyond the brake disk seat38, providing coverage of the first wheel seat anomaly23, first gear seat anomaly25, brake disk seat anomaly27, and the inboard journal anomaly29.

Similarly, the second ultrasonic wedge location17on the radial surface16of the main portion13of the first outboard journal10can be determined by placing the second ultrasonic wedge214on the proximal end12of the first outboard journal10as close to the first wheel seat24(or dust guard seat19) without having the second ultrasonic beam sector scan223affected by any curved step18that may exist on the proximal end12of the first outboard journal10. Locating the second ultrasonic probe210and the second ultrasonic wedge214at the second ultrasonic wedge location17maximizes the coverage of the second ultrasonic beam sector scan223toward the second end22of the inboard journal20. As can be seen inFIG. 1, the second ultrasonic beam sector scan223provides coverage from before the first gear seat26well into the inboard journal20beyond the brake disk seat38, providing coverage of the first gear seat anomaly25, brake disk seat anomaly27, and the inboard journal anomaly29.

FIG. 3is a flow diagram700of an exemplary method for ultrasonic inspection of an axle3. As shown inFIGS. 1 and 2, the axle3includes a longitudinal axis5and an inboard journal20between a first outboard journal10and a second outboard journal50. The ultrasonic inspection can be conducted without having to remove or otherwise disassemble any of the devices mounted on the inboard journal20, including the wheels34,74, gears36,76, brake disk38, or cover40. At step710, the first ultrasonic probe110and the first ultrasonic wedge114are placed at a first ultrasonic wedge location15on the radial surface16of the first outboard journal10. At step720, the axle3is rotated by, e.g., rotating the wheels34,74of the axle3using a roller stand610(FIG. 2). In another embodiment, axle3remains stationary while the ultrasonic probe110is rotated around the axle3using the ultrasonic probe manipulators611(FIG. 2). At step730, a first ultrasonic scan directed to the inboard journal20is performed during rotation of the axle3or the probe110. In one embodiment, the first ultrasonic probe110is a phased array ultrasonic probe, and the first ultrasonic scan is the first ultrasonic beam sector scan123, wherein the first ultrasonic beam sector scan123is within a range between the lower first refracted ultrasonic beam121at a lower first refracted ultrasonic beam angle131of forty degrees and an upper first refracted ultrasonic beam122at an upper first refracted ultrasonic beam angle132of eighty degrees. In another embodiment, the first ultrasonic probe110is a single element probe, and the first ultrasonic scan is an A-scan.

If only a single probe and wedge are to be used to inspect the first end1of the axle3from the first outboard journal10and an additional ultrasonic scan of the inboard journal20is required, then at step740, the first ultrasonic probe110and the first ultrasonic wedge114are placed at a second ultrasonic wedge location17on the radial surface16of the first outboard journal10. In one embodiment, the first ultrasonic wedge location15is proximate to the distal end11of the first outboard journal10and the second ultrasonic wedge location17is proximate to the proximal end12of the first outboard journal10, axially opposite of the distal end11of the first outboard journal10. At step750, a second ultrasonic scan directed to the inboard journal20is performed while the axle3is rotated.

If a second probe and wedge are to be used to inspect the first end1of the axle3from the first outboard journal10and an additional ultrasonic scan of the inboard journal20is required, then at step760, a second ultrasonic probe210and a second ultrasonic wedge214are placed at the second ultrasonic wedge location17on the radial surface16of the first outboard journal10. In one embodiment, the first ultrasonic wedge location15is proximate to the distal end11of the first outboard journal10and the second ultrasonic wedge location17is proximate to the proximal end12of the first outboard journal10, axially opposite of the distal end11of the first outboard journal10. At step770, a second ultrasonic scan directed to the inboard journal20is performed while the axle3is rotated.

In view of the foregoing, embodiments of the method and system for ultrasonic inspection of an axle eliminates the need to remove or otherwise disassemble devices on the inboard journal of the axle. A technical effect is to simplify and reduce the time required to conduct the inspection.

Program code and/or executable instructions embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.