JPH0158019B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a machine for processing a pipe so that its wall thickness is uniform.

An embodiment of the present invention will be described with reference to FIGS. 1-3.

In the mechanical system shown in Fig. 1, numeral 1 is a chuck supported on the headstock (not shown) of the lathe, and the chuck 1 moves four jaws 2 back and forth to grip one end of the pipe P to be machined. The tip of the tailstock shaft is placed against the end plate attached to the other end, and the pipe P is held by the chuck 1 and the tailstock shaft. A pulse generator 3 is rotated by a belt 4 from a main shaft (not shown) of the lathe to detect the rotation angle of the pipe P. Reference numeral 5 denotes a cross-feed table placed on the guide surface of the lathe, on which a cutter box 6 having a rotating shaft 7 is mounted so as to be freely advanced and retracted with respect to the pipe P.
A cutter 8 attached to the rotating shaft 7 is applied to the pipe P to cut its peripheral surface, a threaded rod 9 is screwed into a nut (not shown) provided at the bottom of the cutter box, and this threaded rod is rotated by the control motor 10. When the horizontal feed table 5 scans the entire length of the pipe, the knife box 6 is moved backward by the lever 11 to separate the knife 8 from the pipe. Reference numeral 12 denotes a probe for transmitting and receiving ultrasonic waves, which is attached to the upper surface of the transverse feed table 5 in line with the cutter box 6 in the direction of movement thereof, and transmits and receives ultrasonic waves for measuring the wall thickness of the pipe P in advance of the cutter 8.

The probe 12 is a 5 MHz or 10 MHz shock wave type, and as shown in Fig. 2, a cylinder 14 filled with water 13 and sealed is connected to the front side, and the end face of this is applied to a pipe P to emit ultrasonic waves into the water. , a reflected wave a from the outer wall of the pipe and reflected waves b and c from the inner wall are received, and the water distance W and wall thickness T are measured based on the time difference until each reflected wave enters.

In the wall thickness measuring device, as shown in FIG. 3, a transmitter 16 generates a spike-like high voltage (500V) in synchronization with a signal from an oscillator 15, and when the probe 12 is struck with this voltage, an ultrasonic wave is generated. Part of the ultrasonic wave is reflected by the outer wall of the pipe P, and the remaining part is also reflected by the inner wall of the pipe. The reflected ultrasonic wave is attenuated to about 1/10,000, and this is transmitted to the preamplifier 1.
After being amplified in step 7, it is input into the waveform shaping circuit 18 and shaped into a pulse signal, and this pulse signal is sent to the gate circuit 1.
9 to the interval detection circuit 20, and the data is sent to the computer 22 via the interface 21. The computer 22 uses an 8-bit Z80CPU type. Here, the gate circuit 19 receives the signal from the oscillator 15 via the synchronization circuit 23, and makes the signal valid only when the pulse signal arrives at the expected position, thereby improving the reliability of the processing. In FIG. 3, solid lines indicate paths of ultrasonic waves and other signals and pulse signals, and dotted lines indicate control paths.

One embodiment of the present invention has the above-mentioned configuration, and the pipe P is attached to the chuck 1 and the tailstock shaft and rotated, and the cross-feed table 5 is slowly moved in the longitudinal direction along the pipe. The attached cylinder 14 and rotary blade 8 move while contacting the outer wall of the rotating pipe P, and the probe 12 continuously generates ultrasonic waves and receives reflected waves a, b, and c from the outer and inner walls of the pipe P. Then, the computer 22
As shown in the figure, the water distance W and wall thickness T are determined from the reception time of the reflected wave. Next, the pulse generator 3 delays the inner wall position signal of the pipe P by the time that the probe 12 is ahead of the blade 8 to obtain the target depth of cut. In order to achieve a beautiful finish and extend the life of the blade, it is desirable to change the depth of cut of the blade as smoothly as possible. Therefore, the control section 24 determines the optimum depth of cut and applies it to the blade 8. Through the above process, the cutter 8 makes a deep cut in the thick part, cutting the pipe P to a substantially uniform thickness, as shown in FIG.

The above describes one embodiment of the present invention, and the present invention is not limited to this embodiment, and the design can be changed within the gist of the invention.

According to the present invention, the pipe is held by a chuck and a tailstock shaft supported on the headstock of the lathe, and a cutter box having a rotating cutter and a probe for transmitting and receiving ultrasonic waves are attached to a cross-feed table resting on the guide surface of the lathe. The probe is placed on the side in the direction of movement of the cross feed table rather than the knife box, and the wall thickness of the pipe is determined by the difference in reception time of the reflected waves from the outer and inner walls of the pipe, and the inner wall position signal of the pipe is delayed. Since the required depth of cut is controlled to be applied to the cutter depending on the wall thickness, the pipe can be efficiently machined into a uniform wall thickness.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view of a mechanical system, Fig. 2 is an explanatory diagram showing an ultrasonic reflection path, and Fig. 3 is a system diagram of a wall thickness measurement circuit.
FIG. 4 is a systematic diagram of the cutting process, and FIG. 5 is an explanatory diagram of the depth of cut. 1...Chuck, 5...Transverse feed table, 6...Knife box, 8...Knife, 12...Probe, P...Pipe, a, b, c...Reflected wave.

Claims (1)

[Claims] 1. The pipe is held by a chuck and a tailstock shaft supported on the headstock of the lathe, and a cutter box with a rotary cutter and a probe that transmits and receives ultrasonic waves are attached to the cross feed table resting on the guide surface of the lathe, and the probe is attached to the cutter box. A circuit for determining the wall thickness of the pipe based on the reception time difference of reflected waves from the outer and inner walls of the pipe, means for delaying the inner wall position signal of the pipe, and a means for delaying the inner wall position signal of the pipe. A pipe wall thickness processing machine characterized by comprising a means for applying a required depth of cut to a rotary blade according to the thickness.