JPS6252677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface removal processing apparatus for a rotating body that is capable of removing the surface of a rotating body rotating at a high speed efficiently and with high precision.

Conventionally, as a method for adjusting the dynamic balance of a motor rotor, etc., an unbalanced portion is often removed using a laser beam.
In this case, as the laser beam for processing, a continuous oscillation pulse of spike waves (FIG. 1a) generated by a neodymium glass laser or a ruby laser is used because the pulse output can be increased. However, the above-mentioned neodymium glass laser and ruby laser have a relatively long repetitive oscillation period of each spike wave, so there is a limit to the amount of removal per unit time, and there is a drawback that improvement in processing efficiency cannot be expected. .

Therefore, in order to improve processing efficiency, attempts are being made to use YAG lasers that can increase the repetition rate of oscillation. However, with this YAG laser, when trying to obtain a normal pulse waveform,
When the oscillation rate is repeatedly increased while keeping the pulse width constant, the spike waveform decreases and is shown in Figure 1b.
As shown in the figure, the maximum peak value of the pulse output decreases,
This results in a decrease in the amount of removal processing. This reduction in the amount of removed machining increases rapidly, especially when the rotational speed of the rotating body increases, and for this reason, YAG lasers cannot be applied to the high-speed rotation region of the rotating body, and for this reason, the demand for improved machining efficiency is I couldn't respond.

The present invention has been made focusing on the above circumstances,
The purpose of this is to be able to perform sufficient removal processing, especially in the high-speed rotation region of rotating objects, without reducing the removal amount even if a high-speed repetitive laser beam with few spike waves is used, and to achieve efficient and high-precision removal. An object of the present invention is to provide a surface removal processing device for a rotating body capable of adjusting dynamic balance.

That is, the present invention forms a pulse waveform with a high peak value at the rising edge of a pulsed laser beam and irradiates the rotating body with the pulse waveform, thereby sufficiently heating the processed part with the high peak wave and increasing the light absorption rate. After that, the part to be machined is removed using a low-level laser beam, which enables sufficient removal even in the high-speed rotation region of the rotating body. By starting the excitation of the laser rod a predetermined time earlier than the timing of detecting the center position of the part, it is possible to uniformly and accurately remove the part to be processed without shifting the part.

Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings. FIG. 2 is a schematic configuration diagram of a surface removal processing apparatus for a rotating body in the same embodiment, and numeral 1 in the figure indicates a processing laser apparatus. This processing laser device 1 drives a flash lamp 3 using an excitation power source 2 to emit laser excitation light, and the excitation light is condensed and reflected by a condensing reflector 4 to a YAG laser rod 5.
and excites the YAG laser rod 5. A pulsed laser beam 6 oscillated and output from the YAG laser rod 5 at a high repetition rate is condensed and irradiated onto a part to be processed on the surface of the rotating body 8 via a condensing lens 7. In addition, in the figure, 9a,
9b indicates a resonator mirror.

On the other hand, the rotating body 8 is connected to the bearing 1 via the rotating shaft 10.
1, and this bearing 11 is supported by the elastic member 1.
It is fixed to the base body 13 via 2. and,
The rotating body 8 is rotationally driven by an electric motor (not shown). By the way, the bearing 11 and the rotating body 1
A vibration detector 14 and a rotational phase detector 15 are arranged close to each other on the side surface of the machine 0, and the detection outputs of these detectors 14 and 15 are led to a processing control circuit 16, respectively. This processing control circuit 16 detects a part of the rotating body 8 to be processed, that is, a part to be removed, from the detection output of the vibration detector 14, and also detects a part to be processed that is to be removed and passes over the irradiation position of the laser beam 6. timing,
Detection is performed based on the detection output of the rotational phase detector 15. Note that the rotational phase of the rotating body 8 is as follows:
This is done by detecting the passing timing of a mark marked on the rotating body 8 in advance. Then, the processing control circuit 16 generates a laser control signal a predetermined time earlier than the previously detected center position detection timing of the processed part, and sends this laser control signal to the excitation power source 2 of the processing laser device 1. supplying.

By the way, FIG. 3 shows the circuit configuration of the excitation power source 2, and 3 in the figure indicates a flash lamp. A starting trigger electrode 17 is wound around the outer periphery of the flash lamp 3, and this starting trigger electrode 17 is connected to a high voltage pulse circuit 18. This high-voltage pulse circuit 18 generates an activation trigger pulse to the trigger electrode 17 when a machining control signal is generated from the machining control circuit 16. On the other hand, this excitation power source 2 includes two charging power sources 19 and 20, one low voltage and one high voltage. The output of the low voltage power supply 19 is connected to a capacitor 21,
22 and 23 are charged by passing coils 24 and 25 through them. The charge of this capacitor 23 is
When the flash lamp 3 is activated by a trigger, it is supplied to the flash lamp 3 via a diode 26 and a coil 27, and is discharged in the flash lamp 3. Further, the output of the high voltage power supply 20 is temporarily stored in the capacitor 28, and then supplied to the flash lamp 3 via the coil 30 by firing of the thyristor 29, and is discharged in the flash lamp 3. Here, the ignition timing of the thyristor 29 is determined to be a little later than the activation timing of the flash lamp 3.

Next, the operation of the device configured as above will be explained. When the rotating body 8 as a workpiece is set on the bearing 11 and rotated, the bearing 11 is moved to the elastic member 12.
Since the rotating body 8 is supported via the rotating body 8, the rotating body 8 starts to vibrate according to the unbalance of its weight. This vibration is detected by the vibration detector 14 as a detector output using changes in capacitance and inductance, as shown in FIG. is the fourth
It is detected as shown in Figure CS. As a result, the machining control circuit 16 detects a vibrating portion that is equal to or higher than a predetermined threshold level X from the vibration detection output HS,
That is, the machined part of the rotating body 8 is detected, and the timing at which the center position A of the machined part passes through the laser beam irradiation position is detected based on the rotational phase detection output CS. That is, the center position A of the part to be machined is detected as _T1 hours after the generation timing of the rotational phase detection pulse CS.
Here, if the laser beam is irradiated at the timing of passing the center position A of the part to be processed, the part to be processed will be removed only after the center position. Therefore, the laser beam irradiation start timing needs to be set a predetermined time earlier than the passing timing of the center position A. This advance time is determined by the difference T ₂ between the passing timing of the center position A and the first timing (corresponding to B) at which the threshold level becomes higher than the threshold level X, as shown in Fig. 4.
corresponds to Therefore, the processing control circuit 16 calculates the difference between the center position passing time _T1 and the _T2 ,
The rotational phase detection pulse CS is delayed by this difference T ₃ and this delayed pulse is supplied to the excitation power source 2 of the processing laser device 1 as a laser control signal. When the laser control signal is supplied in this way, the excitation power supply 2 causes the flash lamp 3 to emit light, and as a result,
The YAG laser rod 5 is excited and a pulsed laser beam 6 with a short repeating oscillation cycle of spike waves is irradiated onto the portion of the rotating body 8 to be processed, thereby performing removal processing. At this time, since the irradiation start timing of the laser beam 6 is earlier than the timing of passage of the center position A of the part to be processed, the surface of the rotating body 8 extends over the area before and after the part to be processed, as shown in FIG. It is processed to remove it. In addition, in Figure 5
A' and B' respectively indicate the center position and the position corresponding to the leading edge of the processed part.

Now, the waveform of the laser beam 6 irradiated onto the rotating body 8 is determined as follows. That is, when a laser control signal is supplied from the processing control circuit 16 to the high-voltage pulse circuit 18 of the excitation power source 18, the flash lamp 3 is triggered and first, the charges accumulated in the capacitors 23, 22, and 21 are used for waveform shaping. It is discharged through the coil 27 to the flash lamp 3 as shown in FIG. 6a. Subsequently, at time _t2 , the thyristor 29 is ignited, whereby the charge stored in the capacitor 28 is discharged in the flash lamp 3, as shown in FIG. 6b. As a result, the flash lamp 3 outputs a light emitting pulse as shown in FIG. 6c, in which each of the above-mentioned discharge current waveforms is superimposed, and the YAG laser rod 5 is activated by this light emitting pulse as shown in FIG. 6d. A laser beam 6 of the shape is generated. Here, the high peak waveform at the rise of the light emission pulse output from the flash lamp 3 is caused by the flash lamp 3 being sufficiently discharged and filled with plasma between times _t1 and _t2 , and the discharge resistance being low. Because it is curved, it has a steep rise. In addition, the high peak waveform at the rise of the laser beam oscillated from the laser rod 5 also
Since the excitation level is raised to the level at which the laser rod 5 can start oscillation between _t1 and _t2 , the excitation level becomes steep. Incidentally, the oscillation start timing of the laser rod 5 is _t2 , which is somewhat delayed from the emission start timing _t1 of the flash lamp 3, as described above. Therefore, by advancing the operation start timing of the excitation power source 2, that is, the laser control signal generation timing of the processing control circuit 16, by the above-mentioned t ₂ −t ₁ from point B in FIG. 4, the above-mentioned t ₂
-t The delay in the laser beam irradiation start timing of ₁ minute is absorbed, and the processing start position of the rotating body 8 is determined more accurately.

Then, when the laser pulse output (laser beam 6) obtained as described above is irradiated onto the surface of the rotating body 8, the irradiated part is sufficiently heated by the steep high peak wave at the rise time, and the laser beam is emitted. The light absorption rate of the rotating body 8 is increased, and even if the level of the subsequent laser pulse is low and no spike-like waveform is generated, the surface of the rotating body 8 can be removed sufficiently deeply. At this time, when a YAG laser that repeatedly oscillates at high speed is used as the laser beam, the amount of removed processing decreases significantly as the rotational speed of the rotating body 8 increases, and as shown in FIG. If exceeds ν _A , the amount of removal machining becomes less than m ₁ and machining becomes impossible. However, when a laser pulse with a steep rise and a high peak waveform is used as in this embodiment, the amount of removal of the rotating body 8 increases significantly as shown in FIG. Even in the high-speed rotation region ν _A to ν _B , removal of m ₁ or more is possible.

As described above, according to the apparatus of this embodiment, by irradiating the rotating body 8 with a laser beam that forms a steep, high-peak waveform at the time of startup,
Even using a low-output laser beam with significantly reduced spike-like waveforms due to high-speed repetitive oscillation, sufficiently deep removal can be achieved.
In particular, even in the high speed rotation region of the rotating body 8, a sufficient removal amount can be obtained. As a result, the machining speed can be significantly increased, and machining efficiency can be improved. In addition, the laser beam is
When irradiating the laser beam, the part to be machined is detected from the vibration of the rotating body 8, and the excitation power source 2 is activated a predetermined time earlier than the timing when the part to be machined passes the center position to generate the laser beam 6. Rotating body 8
The entire area to be machined can be removed uniformly and accurately without being biased, and the dynamic balance can be adjusted with high precision.

Note that the present invention is not limited to the above embodiments. For example, if the rotating body 8 is made of a material with good thermal conductivity, the high-peak waveform may be formed not only at one location but at two or more locations. In this case, this can be easily implemented by appropriately controlling the configuration of the excitation power source 2 and the drive timing of the flash lamp 3. As a result, processing efficiency can be further improved. Further, the amount of removal processing, that is, the adjustment of the depth of removal processing, can be easily performed by controlling the pulse width of the high peak waveform. Further, as the laser device for processing, any device that can perform high-speed repetitive oscillation may be used, and other means for generating a laser beam with a high peak wave and detecting the portion to be processed on the rotating body 8 may be used. The means and the like can be modified in various ways without departing from the gist of the present invention.

As detailed above, according to the present invention, even if a YAG laser beam with reduced spike waves due to high-speed repetitive oscillation is used, sufficient removal can be achieved without reducing the amount of machining removal, especially in the high-speed rotation region of the rotating body. Here, it is possible to provide a surface removal processing apparatus for a rotating body that can perform processing, have high processing efficiency, and also adjust dynamic balance with high accuracy.

[Brief explanation of the drawing]

Figures 1a and 1b are laser pulse waveform diagrams for use in explaining the conventional method of the present invention, Figures 2 to 7 are diagrams for explaining an embodiment of the present invention, and Figure 2 is a diagram of a rotating body. FIG. 3 is a schematic diagram of the surface removal processing apparatus, FIG. 3 is a schematic diagram of the laser excitation power source, and FIGS. 4 to 7 are diagrams used to explain the operation. 1... laser device for processing, 2... excitation power source, 3
...Flash lamp, 5...YAG laser rod, 6...Laser beam, 8...Rotating body, 11...
... Bearing, 12 ... Elastic member, 14 ... Vibration detector, 15 ... Rotation phase detector, 16 ... Processing control circuit.

Claims (1)

[Claims] 1 In a surface removal processing device for a rotating body that excites a solid-state laser oscillator with a light emission pulse of a laser excitation lamp and irradiates the surface of a rotating body with a laser beam to remove the surface of the rotating body, a part to be processed on the surface of the rotating body is removed. means for detecting, means for starting the light emitting operation of the laser excitation lamp a predetermined time earlier than the detection timing of the center position of the processed part detected by the means, and a light emission pulse waveform generated from the laser excitation lamp. 1. A surface removal processing device for a rotating body, comprising means for forming a waveform with a high peak value at the start of a light emission operation.