JPS6141673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a nozzle drilling method and apparatus for forming a through hole for injecting fuel into a combustion chamber from a fuel nozzle.

In the conventional fuel nozzle, as shown in FIGS. 1A and 1B, a number of through holes 2, 2', etc. are provided in a nozzle 1 in a circumferential manner, and fuel is injected in the form of mist from the through holes. . Therefore, the diameter of the through hole is 0.1 to 0.4
It is required to be as fine as millimeter and highly precise, and to spray uniformly into the combustion chamber, it is also required to be very strict, with almost no pitch error in the through holes.

Conventionally, in order to form the above-mentioned fine and highly accurate through holes 2, drilling has been performed using a high energy density heat source such as a pulsed laser. In this laser drilling process, as shown in Fig. 2, a pulsed laser beam 3 that is generated intermittently is focused by a convex lens 4, and dozens of shots are irradiated onto the position that will become the nozzle 5 to form a through hole. It is.
That is, in order to penetrate the plurality of nozzle ports provided in the nozzle, first, dozens of pulsed laser beams are irradiated to the first nozzle port to penetrate the nozzle ports at once, and then the nozzle 1 is rotated around the rotating shaft 6. The center is rotated to a desired angle and several tens of laser beams are irradiated again to form a second nozzle. In this way, holes are sequentially drilled in the nozzle portion 5, but in this case, since several tens of laser beams are irradiated to the same location, the temperature distribution of the nozzle becomes extremely uneven, resulting in thermal deformation. This thermal deformation caused a large error in the pitch of the through holes, and the fuel was not uniformly injected from the through holes, which had an adverse effect on product performance such as fuel efficiency.

As a result of intensive research aimed at improving these drawbacks, the present invention has discovered a method for preventing thermal deformation and ensuring high accuracy in the positioning of the pitches, etc. of the through holes when providing a plurality of through holes in the fuel nozzle. It is something. That is, the present invention provides a nozzle drilling method in which a through hole is formed by irradiating a laser beam onto the nozzle of a nozzle in which a plurality of nozzles are circumferentially provided at predetermined intervals. After irradiating several laser pulses or less, the irradiation step of sequentially irradiating laser pulses from the second nozzle to the final nozzle in the same manner as above is repeated a desired number of times to form a through hole in the nozzle. This is a nozzle drilling method.

Further, the present invention attaches a reversing plane mirror to the laser generator, allows the pulsed laser beam generated by the laser generator to proceed from two directions, the front direction and the opposite direction, with or without passing through the plane mirror, and A nozzle drilling device is provided with a laser beam direction switching device for switching the angle, and an optical device including a plane mirror and a convex lens is attached to the switching device, and the laser beam from the convex lens is irradiated to the nozzle part. .

In this way, the present invention provides a nozzle with 10
When irradiating ~20 nozzles with a pulsed laser beam, each nozzle is irradiated with 1 to 2 to 3 laser beams at a time, without irradiating dozens of laser beams at once to form a through hole. Without increasing the temperature of the nozzle, irradiate a small number of shots one after another in the same way,
After irradiating all the nozzle parts, the same irradiation as above is repeated again to the original nozzle part to form a through hole. Therefore, the nozzle part is not subjected to thermal deformation, so that a through hole with extremely high dimensional accuracy can be bored.

In addition, the device does not rotate the nozzle to be processed and switch the irradiation position of the laser beam, but it is equipped with a laser beam direction switch that allows the path of the laser beam to be easily changed. It is possible to irradiate laser pulses to

An example of the present invention will be explained in detail based on the drawings.

As shown in FIGS. 3 and 4, the nozzle 1 is provided with 16 nozzle ports, and the pulsed laser beam 3 generated from the laser generator 7 is transferred to the laser beam direction switch 8.
further by a convex lens 9 and a plane reflecting mirror 10.
It has 16 types of laser beam paths.
In this case, in order to sequentially switch and convey the laser beam to 16 types of laser beam paths, a laser beam direction switch is provided, which is equipped with a plurality of plane mirrors having different reflection angles.

In addition, in the present invention, since the laser beam 3 generated by the beam generator 7 must be irradiated onto the nozzle provided around the entire circumference of the nozzle, the laser beam enters from two directions, the front direction and the opposite direction of the direction changer. It is something that forces you to do something. In other words, the nozzle on the right side (front) direction can be irradiated with the laser beam 3 from the beam generator 7 by directing it directly to the laser beam direction switch 8 and then using an optical device. For the nozzle in the left side (back side) direction, a reversing plane reflector 11 is installed between the beam generator 7 and the laser beam direction switch 8.
After passing through this reflecting mirror, a plane mirror 12,
12' and 12'', the laser beam enters from the left side (back side) of the direction switch 8, and is then irradiated by the same optical device as described above.

In this way, the present invention uses a laser beam direction switch to change the path of the beam, making it possible to accurately irradiate a predetermined position of the nozzle with a laser pulse without rotating the nozzle as in the conventional method. However, when a simple rotating plane mirror 13 as shown in FIG. This is magnified by the use of equipment, resulting in large aiming errors. Therefore, if there is an error in aiming, even if the hole is drilled little by little in the nozzle, it will be difficult to re-irradiate the laser beam accurately onto the hole that has already been dug, resulting in fatal damage.

One example of the laser beam direction switching device 8 according to the present invention is shown in FIG. 6, in which a desired number of plane mirrors 15 attached at a desired angle are slidably inserted into a shaft rod 14 having sufficient rigidity. The direction of the laser beam can be freely switched by moving the plane mirror in the axial direction. In this case, as long as the shaft rigidity is sufficient, the aiming error will be 0.
This allows for highly accurate drilling of the nozzle. 7 shows another example of the laser beam direction switch 8, in which the shaft rods 14, 1
4', reflective plane mirrors 15 each having different reflection directions;
15', a plurality of unit mirror bodies movable only in the axial direction are arranged in parallel at positions where they can cross the laser beam path, so that the laser beam is reflected only on a desired unit mirror body.

Next, examples of the present invention will be described.

Example Using a pulsed laser (YAG laser), the nozzle was equipped with 16 nozzles at equal intervals of 0.8 mm, and the above laser was irradiated with two shots each, and this process was repeated five times. A through hole was formed by irradiating the nozzle with 10 laser pulses each.

The temperature distribution of the thus obtained nozzle was maintained uniformly in the circumferential direction, no thermal deformation was observed, and the pitch error was less than ±0.01 mm.

In addition, as in the conventional method, after forming a through hole by irradiating each nozzle with 10 laser beams at a time, a through hole was similarly provided at the next nozzle, and the temperature distribution of the fuel nozzle was Thermal deformation occurred on one side, and the pitch error reached a maximum of 0.2 mm.

As described in detail above, the present invention has remarkable effects such as being able to perform highly accurate drilling in pitches and the like since thermal deformation does not occur during processing.

[Brief explanation of the drawing]

Figure 1 shows a conventional fuel nozzle.
is a cross-sectional view, B is a bottom view, FIG. 2 is an explanatory diagram showing a conventional method of drilling a hole in a nozzle, FIGS. 3 and 4 show an example of the present invention, and FIG. 3 is a schematic diagram. 4 is a schematic plan view, FIG. 5 is a perspective view of a conventional reflective plane mirror, and FIGS. 6 and 7 are schematic explanatory views showing one example of a laser beam direction switch according to the present invention. FIG. 8 is an explanatory view of the spout section provided in the nozzle in the present invention. 1... Nozzle, 2... Through hole, 3... Laser beam, 4... Convex lens, 5... Nozzle part, 6...
Axis, 7... Laser beam generator, 8... Beam direction switch, 9... Convex lens, 10... Plane mirror, 1
1... Plane mirror for reversal, 12... Plane mirror, 13...
Plane mirror, 14... shaft rod, 15... plane mirror.

Claims (1)

[Claims] 1. A nozzle drilling method in which a through hole is formed by irradiating a laser pulse to the nozzle of a nozzle having a plurality of nozzles circumferentially provided at predetermined intervals, the first method comprising: After irradiating the nozzle with several pulsed laser beams or less, the irradiation step of sequentially irradiating the laser beam from the second nozzle to the final nozzle in the same manner as above is repeated a desired number of times to form a through hole in the nozzle. A nozzle drilling method characterized by forming a hole. 2. In a nozzle drilling device that forms a through hole by irradiating a pulsed laser beam generated from a laser generator onto the orifice of a nozzle, a reversing plane mirror is attached to the laser generator, and the pulsed laser beam is applied to the plane mirror. A laser beam direction switch is provided to allow the laser beam to enter from two directions, the front direction and the opposite direction, with or without the aid of a A nozzle drilling device characterized by irradiating a nozzle with a laser beam from a convex lens. 3. A desired number of movable plane mirrors with different laser beam reflection directions are provided as a laser beam direction switch, and by moving the plane mirrors and adjusting the reflection angle, laser beams are sequentially irradiated to predetermined positions of the nozzle part. A nozzle drilling device according to claim 2, characterized in that: