JP2002079389A - Method and equipment for laser beam welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and equipment for laser beam welding by a deformation at a penetrated part is prevented by regulating the irradiation angle of a laser beam with which a member to be welded is irradiated and the generation of the deformation in the welding is suppressed as a result. SOLUTION: The laser beam is irradiated in a manner that the optical axis L is set at a predetermined angle θ with respect to the normal line N of an injector when the laser beam welding is performed by lapping a nozzle body 30 and an injector housing 50 which construct the injector which is a member to be welded. The injector has a vector Vr of rotating direction because it is rotated in the direction denoted by an arrow R, and the irradiated laser beam has a vector Vi of the incident direction. When these vectors are composed, the direction of the resultant vector Vs coincides with the normal direction N of the member to be welded. Thus, the penetrated part 70 made by the laser beam welding has a symmetrical form with respect to the normal line N and the deformation is prevented. As a result, the generation of a deformation made during the welding is suppressed and the valve density of the injector is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a laser welding method and a laser welding apparatus.

[0002]

2. Description of the Related Art From the viewpoint of environmental protection such as prevention of air pollution, it is required to remove harmful substances contained in exhaust gas discharged from diesel engines and gasoline engines.
Particularly in recent years, regulations on the amount of harmful substances contained in exhaust gas have been tightened. In order to reduce the emission of harmful substances, it is necessary to precisely define the fuel injection timing or injection amount. Therefore, injectors that inject fuel into cylinders or intake systems of diesel engines and gasoline engines are required to have high valve tightness.

Conventionally, the injector has a structure in which fuel injection is stopped by abutting a valve seat formed on a nozzle body with a contact portion of a valve needle.
Since the sealing between the valve seat and the contact portion determines the tightness when the valve is closed, the valve seat and the contact portion are machined with high precision.

[0004]

The nozzle body on which the valve seat is formed must be welded to the injector housing. However, when the nozzle body and the injector housing are overlapped and welded, distortion may occur during welding. Conventionally, laser welding using laser light has been used. When distortion occurs, even when the valve seat portion and the contact portion are machined with high precision, a gap is formed between them, and the valve tightness may be reduced.

As shown in FIG. 8, the laser beam is irradiated perpendicularly to the joint between the nozzle body 100 and the injector housing 110, that is, along the normal line N of the nozzle body 100 and the injector housing 110, as shown in FIG. Occurs. Since the joint between the nozzle body 100 and the injector housing 110 is continuously welded in the circumferential direction, the laser light is emitted while rotating the injector housing 110 in which the nozzle body 100 is assembled in the circumferential direction. However, as shown in FIG. 8, a vector Vr in the rotation direction of the nozzle body 100 and the injector housing 110 and a vector Vr in the direction of incidence of the laser beam.
From i, the combined vector Vs is combined. Penetration portion 120 formed by laser welding is formed along composite vector Vs. Therefore, penetration part 1 by laser welding
As shown in FIG. 8, the shape of 20 is asymmetrical about the normal line N of the injector 2 as an axis. As a result, distortion occurs due to the asymmetrical shape of the penetration portion 120, which leads to distortion during welding, which causes a reduction in valve tightness of the injector.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser welding method and a laser welding method for preventing distortion of a penetration portion by defining an irradiation angle of a laser beam applied to a member to be welded and reducing generation of distortion during welding. It is to provide a welding device.

[0007]

According to the laser welding method of the present invention, the member to be welded and the laser irradiation part are relatively movable. That is, the member to be welded moves and the laser irradiation unit is fixed, the member to be welded is fixed and the laser irradiation unit moves, or the member to be welded and the laser irradiation unit move relative to each other. At this time, the laser light is irradiated such that a combined vector obtained by combining the relative movement direction vector of the member to be welded and the incident direction vector of the laser beam is in a direction along the normal line of the member to be welded. That is, the irradiation direction of the laser beam is defined so that the combined vector and the normal line of the member to be welded match.
Therefore, the penetration portion is formed along the normal line of the member to be welded, and the occurrence of distortion is prevented. Therefore, distortion generated at the time of welding can be reduced. For example, when laser welding the nozzle of the injector and the injector body, the tightness can be improved. In addition, the incident direction vector is a vector that is irradiated with laser light on the member to be welded, and travels inward in the normal direction of the member to be welded through a penetration portion that is melted by the irradiated laser light.

According to the laser welding apparatus of the third or fourth aspect of the present invention, the laser beam irradiating section is movable relative to the supporting section supporting the member to be welded. The laser beam irradiator is disposed at a position where laser beam irradiation can be performed so that the combined vector and the normal of the member to be welded match. for that reason,
The penetration portion is formed along the normal line of the member to be welded, thereby preventing distortion. Therefore, distortion generated at the time of welding can be reduced.

According to the laser welding apparatus according to the fifth aspect of the present invention, the support portion is driven by the drive portion so as to be rotatable in the circumferential direction. Therefore, the laser beam is continuously irradiated in the circumferential direction on the outer peripheral portion of the member to be welded by fixing the laser irradiation unit and rotating the support unit. Therefore, it is possible to uniformly irradiate the laser beam in the circumferential direction of the member to be welded, and it is possible to reduce the occurrence of distortion.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; As shown in FIG. 2, the laser welding apparatus 1 according to one embodiment of the present invention includes a support unit 11, a drive unit 12, and a laser irradiation unit 13. The injector 2 that is a member to be welded is supported by the support portion 11. The drive unit 12 is capable of driving the support unit 11 to rotate in a certain direction. When the driving unit 12 drives the support unit 11, the support unit 11 rotates in the circumferential direction. The laser irradiation unit 13 is provided outside the support unit 11. The laser irradiating unit 13 is disposed at a position where the optical axis of the irradiating laser light is at a predetermined angle θ with respect to the normal to the injector 2. Since the laser irradiating section 13 is fixed, the injector 2 supported by the supporting section 11 rotates together with the supporting section 11 so that the injector 20 is rotated.
Is irradiated with laser light in the circumferential direction.

The injector 2 as a member to be welded will be described. As shown in FIGS. 3 and 4, the injector 2 applied as a member to be welded in the present embodiment is used for a gasoline engine. The injector 2 has a substantially cylindrical shape, and mainly includes a nozzle body 30, a valve needle 40,
It has an injector housing 50 and an electromagnetic drive section 60. The nozzle body 30 is provided at its tip with an injection hole cover 32 for improving atomization of fuel injected from the injection hole 31. A valve seat 33 is formed on the inner peripheral side of the nozzle body 30. The valve needle 40 has an abutting portion 41 formed near the tip. This contact part 4
When 1 is seated on the valve seat portion 33, the injection of fuel is stopped, and when the contact portion 41 is separated from the valve seat portion 33, the fuel is injected. The valve needle 40 is urged toward the valve seat 33 by a spring 42. When no current is applied to the coil 61 of the electromagnetic drive unit 60, the contact portion 41 is urged by the spring 42 to cause the valve seat 33 to move. Is sitting. When a current is applied to the coil 61, the valve needle 40 is attracted in the direction of the coil 61 against the urging force of the spring 42, and the contact portion 41 is
Leave 3

The nozzle body 30 is joined to the injector housing 50. As shown in FIG. 4, the nozzle body 30 is inserted into the inner peripheral side of the injector housing 50, and laser light is emitted from the outer peripheral side of the injector housing 50. The laser beam emitted from the laser irradiator 13 is supplied to the nozzle body 30 and the injector housing 5.
Irradiation is performed on the welding portion 51 with 0. This welding part 51
Is set in the circumferential direction along the outer peripheral portion of the injector housing 50.

Next, the arrangement and operation of the laser irradiation unit 13 will be described. The laser irradiator 13 is disposed radially outside the injector 2 supported by the support 11 as shown in FIG. The laser light irradiated from the laser irradiation unit 13 is not irradiated perpendicularly to the circumferential direction of the outer peripheral portion of the injector 2, and as shown in FIG.
Is irradiated from a direction forming a predetermined angle θ with respect to a normal line N of the injector 2. The reason for setting the position of the laser irradiation unit 13 as described above is as follows.

Injector 2 supported by support 11
Is driven to rotate in the direction of arrow R shown in FIGS. Therefore, the injector 2 has a moving direction vector Vr as shown in FIG. on the other hand,
Since the laser light is emitted from the angle θ, the melted portion by the laser light has the incident direction vector Vi. A combined vector Vs is obtained from the moving direction vector Vr and the incident direction vector Vi. That is, the laser beam is irradiated such that the resultant vector Vs is in the direction along the normal line N of the injector 2.

By irradiating the laser beam from the above direction, the energy of the laser beam emitted from the laser irradiator 13 and incident on the injector 2 advances in the direction of the combined vector Vs, that is, in the normal direction of the injector 2. Therefore, the shape of the penetration part 70 formed by the laser welding is symmetric with respect to the axis of the normal line N of the injector 2 as shown in FIG. As a result, distortion of the penetration portion 70 is prevented, and occurrence of welding distortion in the nozzle body 30 and the injector housing 50 is reduced. Therefore, the laser irradiation unit 13 is disposed at a position where the axis L of the irradiated laser light forms a predetermined angle θ with respect to the normal N of the injector 2.

The laser beam is continuously irradiated in the circumferential direction along the outer peripheral portion of the injector 2 with the rotation of the injector 2 supported by the support portion 11. Therefore, the penetration portion 70 is formed continuously in the circumferential direction of the injector 2 as shown in FIG.

After the laser welding is completed, the result of measuring the roundness near the valve seat 33 is as shown in FIG.
For comparison, FIG. 7 shows the roundness in the vicinity of the valve seat when the laser beam is irradiated from the normal N direction of the injector 2 as in the related art. 6 and 7, solid lines S1, S
2 is the measured shape in the vicinity of the valve seat, and broken lines B1, B
2 indicates a perfect circle. S1 and B1 indicate the small diameter side, and S2 and B2 indicate the large diameter side.

When these are compared, as shown in FIG. 1, by irradiating a laser beam from a predetermined angle θ, as shown in FIG. 6, distortion during welding is reduced, and roundness is improved. I understand. The irradiation angle θ of the laser beam is set according to the shape or rotation speed of the member to be welded such as the injector 2 or the incident energy of the laser beam.

When performing laser welding, the injector 2 is mounted on the support portion 11, and a laser beam is radiated from a laser radiating portion 13 disposed radially outside the mounted injector 2 to a welding portion 51. In the state where the laser beam is being emitted, the drive unit 12 drives the support unit 11 on which the injector 2 is supported to rotate at a constant speed. Thereby, the laser beam is continuously irradiated in the circumferential direction along the outer peripheral portion of the injector 2, and laser welding is performed on the entire circumference of the injector 2. When the injector 2 makes one rotation in the circumferential direction, the welding portion 51 moves the outer peripheral portion of the injector 2 by one.
Go around. In the present embodiment, the rotation angle of the support 11 is set to 180
° or more.

As described above, according to the laser welding apparatus 1 of the present embodiment, the axis L of the laser beam emitted from the laser irradiator 13 is at a predetermined angle θ with respect to the normal N of the injector 2. A laser irradiator 13 is provided. Thereby, the penetration part 70 of the welding part 51 becomes symmetrical with respect to the normal line N of the injector 2. for that reason,
The distortion at the time of welding due to the distortion of the penetration portion 70 is reduced. Therefore, the roundness of the valve seat 33 is improved, and the valve density of the injector 2 can be improved.

As described above, in the embodiment of the present invention, the example in which the injector is applied as the member to be welded has been described. However, the member to be welded to which the present invention is applied is not limited to the injector. The member to be welded is not limited to a cylindrical member like the injector described in the embodiment, but can be applied to a member to be welded having a flat outer peripheral portion.

In one embodiment of the present invention, the supporting portion for supporting the injector, which is the member to be welded, rotates. However, a configuration in which the laser irradiation unit moves around the fixed member to be welded, or a configuration in which the laser irradiation unit and the member to be welded move in the same or opposite directions, respectively, is also possible.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an injector welded by a laser welding apparatus according to one embodiment of the present invention, and showing a laser welded section having a cross section taken along line II of FIG.

FIG. 2 is a schematic diagram showing a configuration of a laser welding apparatus according to one embodiment of the present invention.

FIG. 3 is a sectional view showing an injector applied to the laser welding apparatus according to one embodiment of the present invention.

FIG. 4 is an enlarged view of the vicinity of a valve seat in FIG. 3;

FIG. 5 is a schematic view showing a laser welded portion of a cross section taken along line II of FIG. 4, and is a diagram showing a shape of a penetration portion.

FIG. 6 is a schematic diagram showing roundness near a valve seat of an injector welded by a laser welding apparatus according to one embodiment of the present invention.

FIG. 7 is a schematic diagram showing roundness in the vicinity of a valve seat portion of an injector, and is a diagram when welding is performed by a conventional laser welding device for comparison with FIG.

FIG. 8 is a view for explaining a conventional laser welding method, and is a view showing the same parts as in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser welding apparatus 2 Injector (weld member) 11 Support part 12 Drive part 13 Laser irradiation part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norio Tanaka 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Yoshiki Kariya 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. Inside Denso (72) Inventor Tokio Hirune 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Hideaki Shirai 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture F-term ( Reference) 3G066 AA01 AB02 AD12 BA36 BA55 CC01 CC06U CC14 CD04 CE22 4E068 BA01 BG00 CE04 DA02 DA16

Claims (5)

[Claims] 1. A laser welding method for irradiating a laser beam to a member to be welded from a laser irradiating part movable relative to the member to be welded, wherein the laser beam is used to relatively move the member to be welded. A laser welding method, characterized in that the member to be welded is irradiated such that a combined vector obtained by combining a direction vector and an incident direction vector of the laser beam becomes a normal direction of the member to be welded. 2. The laser welding method according to claim 1, wherein the member to be welded has a cylindrical shape, and the laser beam is irradiated from a radially outer side of the member to be welded. 3. A laser welding apparatus for irradiating a member to be welded by irradiating a laser beam to weld the member, wherein the supporting member supports the member to be welded, and is disposed movably relative to the supporting member. The laser beam is emitted such that a combined vector obtained by combining the relative movement direction vector of the member to be welded supported by the support portion and the incident direction vector of the laser beam is in the direction along the normal line of the member to be welded. A laser welding device comprising: a laser beam irradiation unit for irradiating the laser beam. 4. The laser welding apparatus according to claim 3, wherein the member to be welded has a cylindrical shape, and the laser irradiation section is disposed radially outside the member to be welded. 5. The laser welding apparatus according to claim 4, wherein the support section is rotatable in a circumferential direction by a driving section that drives the support section.