Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/22—Details, e.g. general constructional or apparatus details
  • G01N29/26—Arrangements for orientation or scanning by relative movement of the head and the sensor
  • G01N29/27—Arrangements for orientation or scanning by relative movement of the head and the sensor by moving the material relative to a stationary sensor
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
  • G01N29/22—Details, e.g. general constructional or apparatus details
  • G01N29/24—Probes
  • G01N29/2412—Probes using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/04—Wave modes and trajectories
  • G01N2291/042—Wave modes
  • G01N2291/0423—Surface waves, e.g. Rayleigh waves, Love waves
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/10—Number of transducers
  • G01N2291/101—Number of transducers one transducer
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2291/00—Indexing codes associated with group G01N29/00
  • G01N2291/26—Scanned objects
  • G01N2291/269—Various geometry objects
  • G01N2291/2696—Wheels, Gears, Bearings

Definitions

• the invention relates to a device for controlling an ultrasonic wheel test system for railway wheels with a proximity switch arrangement which detects the position of the wheel to be tested and with a transceiver ultrasound transducer which are arranged in a section of a rail to be driven over by the wheel to be tested.
• An electromagnetic ultrasonic transducer for such a device is described in DE-PS 32 18 453 and permits non-destructive testing of the running surface of railroad wheels by means of ultrasonic surface waves while driving over a rail section.
• An inductive proximity switch for example, can be used to activate the ultrasonic transducer of the wheel test system at exactly the right moment.
• Inductive proximity switches for automatic monitoring and control of the movement of rail vehicles are frequently used in the field of signaling and shunting technology as integrated proximity switches and are referred to as rail head contacts.
• Such rail head contacts and also double rail head contacts are described in S + D - Signal und Draht, 72nd Year, September 1980, Issue 9, pages 166 to 172.
• the known double contacts work in the differential method and, together with an interface module and a directional module, generate an electrical impulse that depends on the direction of travel and speed of the rail vehicle when the wheel that rolls over covers a minimum distance that depends on the wheel diameter, tire profile and distance of the wheel surface from the sensor as well as the size and the switching Characteristic of the sensor is dependent. In general, this minimum distance is between 60 and 120 mm.
• there is a switching point inaccuracy which is sufficient when counting axes and when controlling signals and switches, but which leads to problems when ultrasonic wheel test systems are to be controlled which have a switching point accuracy of less than 5 mm desire.
• the object of the invention is to provide a device for controlling an ultrasonic wheel testing system for railway wheels, which ensures high accuracy regardless of different disturbance variables, such as different speeds, wheel profiles and lift-offs .
• a first and a second proximity switch connected to a time measuring device are arranged in the direction of travel upstream of the ultrasound transducer and that in the direction of travel between the second proximity switch and the ultrasound transducer in a second
• a third proximity switch is provided, which is connected to a second time measuring device, by means of which an output signal can be generated after a delay time has elapsed, which is derived from the time recorded in the first time measuring device by dividing by the distance ratio from the first distance by the second distance.
• the three proximity switches are controlled via a control logic with a direction serving first counter and are connected to a second counter serving as a second time measuring device, which count the clock pulses of an oscillator in opposite directions, the first counter being able to be reset before the start of the count and the second counter having the final count of the first counter.
• the first counter is, for example, an up counter that can be reset at the start of a measurement, the counter reading of which can be transferred to the second counter at the end of the first time measurement, which counts down to zero. If the ratio of the distances is chosen so that the first distance is twice as large as the second distance, the arrangement is such that the number of cycles supplied to the second counter per unit of time is twice as high as the number of cycles supplied to the first counter per unit of time .
• the first and the second proximity switches serve to detect a time, the measurement errors having a compensating effect on the delay time of the second counter.
• FIG. 1 shows a cross section through the section of a rail in the region of the first proximity switch of the device according to the invention, together with a schematic representation of the wheel profile of a railway wheel
• Fig. 3 is a block diagram of the device for controlling an ultrasonic wheel test system according to the invention.
• FIG. 1 shows schematically a wheel tire profile 1 of a railway wheel that rolls on the running mirror of a rail 2, in which a first proximity switch 3 is provided in a receiving bore 4.
• the first inductive proximity switch 3 is connected via a cable 5 to an electronic device shown in the block diagram in FIG. 3.
• FIG. 2 shows a top view of the rail 2, which in its running mirror has a second inductive proximity switch 6 and a third inductive proximity switch 7 in addition to the first proximity switch 3 in the direction of travel or test direction. Furthermore, a transceiver ultrasound transducer 8 with a coil winding 9 can be seen in FIG. 2.
• the ultrasound transducer 8 When the rail section shown in FIG. 2 is passed over, the ultrasound transducer 8 generates an ultrasound pulse precisely when the wheel axis is above the center of the ultrasound transducer 8 is located so that an ultrasonic inspection of the tread of the railroad wheel passing over can be carried out.
• the rail 2, the associated second rail of which cannot be seen in the drawing, rests in the usual way on sleepers, of which a sleeper 10 is shown schematically in FIG. 2.
• the center of the ultrasonic transducer 8 is illustrated in FIG. 2 by a line 11. Contrary to the direction of travel or test direction, the third proximity switch 7 is arranged to the left of the line 11 at a / 2 distance. The distance between the third proximity switch 7 and the line 11 is, for example, 20 mm.
• the second proximity switch 6 is located approximately 100 mm in front of the line 11, above which the axis of the wheel to be tested should be at the time of the test.
• the distance a between the first proximity switch 3 and the second proximity switch 6 is, for example, 40 mm, so that the first proximity switch 3 is approximately 14 cm in front of the line 11.
• a contact signal K1 is first generated in the first proximity switch 3, the front edge of which acts on control logic 15 of an electronic circuit shown in FIG. 3.
• the control logic 15 has 3 inputs 16, 17, 18, the input 16 having the contact signal K1 applied to it.
• the proximity switch 6 generates a contact signal K2, which is fed to the control logic 15 via the input 17 and whose trailing edge is evaluated.
• the third proximity switch 7 generates a contact signal K3 which acts on the input 18 of the control logic 15.
• the control logic 15 is connected to a first counter 19, which is connected as an up counter, and to a second counter 20, which is connected as a down counter.
• the second counter 20 has a clock input 21 which is supplied with the clock signal from a quartz-stable oscillator 22.
• the clock output 23 of the oscillator 22 is also connected to a divider circuit 24, which reduces the clock signal in a ratio of 1: 2 and feeds it to the clock input 25 of the first counter 19.
• the output 26 of the first counter 19 is connected to a memory 27, which makes it possible to temporarily store the counter reading at the output 26.
• the data output of the memory 27 is connected to the counter input 28 of the second counter 20.
• Both the first counter 19 and the second counter 20 are preferably a counter with a resolution of 16 bits, which is why the memory 27 is a memory with a single memory location for a word length of 16 bits.
• the second counter 20 connected as a down counter has a zero output 29 which always delivers a signal when the current counter reading is zero.
• the zero output 29 is connected to a driver 30, which is connected to a trigger output 31, to which a pulse signal is present when the center of the railway wheel to be tested is exactly above the line 11 in FIG. 2.
• the first counter 19 is reset to zero using the control logic 15.
• the control logic 15 When the leading edge of the contact signal K1 occurs, the control logic 15 generates a start signal at its first output 41 so that, starting with the leading edge of the contact signal K1, the first counter 19 begins to count the clock pulses of the oscillator 22 which are divided down 1: 2.
• the control logic 15 in turn generates a stop signal with the trailing edge of the contact signal K2 and a takeover signal at the second output 42 which is connected to the takeover input of the memory 27, so that the memory 27 takes over the counter result present at the time of the trailing edge of the contact signal K2.
• the counter result temporarily stored in the memory 27 is taken over into the second counter 20 until the contact signal K3 generated with the aid of the third proximity switch 7 occurs.
• a start signal is transmitted to the second counter 20 via the third output 43 of the control logic 15, so that it begins to count down.
• the clock input 21 receives clock signals whose frequency is twice as large as the clock signals at the clock input 25 of the first counter 19.
• the distance a between the first proximity switch 3 and the second proximity switch 6 is twice as large
• the second counter 20 comes to zero exactly when this is in Fig. 2 is from left to right evenly moving railway wheel exactly above the center of the ultrasonic transducer 8.
• the ultrasound generation and the start of the ultrasound test is triggered by the signal occurring at the zero output 29 and amplified in the driver 30.
• the distance ratios can be changed somewhat, but it is expedient if the distance between the first proximity switch 3 and the second proximity switch 6 is substantially greater than the distance between the third proximity switch 7 and the center of the ultrasonic transducer 8 illustrated by the line 11, because the various sources of error are then best compensated for.
• the error sources are error sources resulting from the switching behavior of the inductive proximity switches, because the switching behavior of the proximity switches is dependent on the object speed, the different wheel profiles and the object distances.

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• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Electromagnetism (AREA)
• Train Traffic Observation, Control, And Security (AREA)

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ID=6364995

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Citations (7)

Family Cites Families (2)

• 1988
  • 1988-10-13 DE DE19883834828 patent/DE3834828C1/de not_active Expired - Lifetime
• 1989
  • 1989-08-29 WO PCT/DE1989/000564 patent/WO1990004173A1/de unknown

Patent Citations (7)

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