JP2002283457A - Laser fusing method for resin parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient joining strength without using a pressure fixture even if a gap is present between joining end surfaces. SOLUTION: The laser fusing method consists of an arranging process for opposing the mutual end surfaces of the joining end 10 of pervious resin material 1 pervious to a laser beam and the joining end 20 of an absorbable resin material 2 having absorbability with respect to a laser beam to each other and an irradiation process for heating and melting the mutual joining end surfaces of the pervious resin material 1 and the absorbable resin material 2 by irradiation with a laser beam from the pervious resin material 1 to integrally join them. In the irradiation process, at least one end of the joining end surface (interior of a hollow body) among both joining end surfaces is irradiated with a laser beam in a reduced pressure atmosphere to allow the molten resin of the joining end surface of the absorbable resin material 2 to flow toward the reduced pressure atmosphere to fill the gap between the joining end surfaces with the molten resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser-welding laser-transmissive resin material and a laser-absorptive resin material. Laser welding method of resin parts to be joined to
More specifically, the present invention relates to a laser welding method for a resin component, which can solve problems such as insufficient bonding strength caused by the presence of a gap at a welding interface.

[0002]

2. Description of the Related Art In recent years, from the viewpoints of weight reduction and cost reduction, it has been frequently practiced to convert parts in various fields, such as automobile parts, into resin to obtain a resin molded product. Also, from the viewpoint of increasing the productivity of the resin molded product, a method is often employed in which the resin molded product is divided into a plurality of pieces in advance and molded, and these divided molded articles are joined to each other.

Here, a laser welding method has conventionally been used as a method for joining resin materials. For example, in Japanese Patent Application Laid-Open No. Sho 60-214931, after laminating a transmissive resin material that is permeable to laser light and an absorptive resin material that is capable of absorbing the laser light, A laser welding method is disclosed in which a laser beam is irradiated from the side of the transparent resin material to heat and melt the bonding end surfaces of the transparent resin material and the absorbing resin material so as to integrally bond the two.

In this laser welding method, the laser light transmitted through the transparent resin material reaches and is absorbed by the joining end face of the absorbing resin material, and the absorbed laser light is accumulated as energy. As a result, the joining end face of the absorbent resin material is heated and melted, and the heat is transferred from the joining end face of the absorbent resin material to heat and melt the joining end face of the transparent resin material. If the joining end surfaces of the permeable resin material and the absorbing resin material are heated and melted and then solidified by cooling, the two can be integrally joined.

[0005] In the laser welding as described above, the joint end face of the transparent resin material is heated and melted by heat transfer from the joint end face of the absorbent resin material. In order to avoid a decrease in bonding strength due to the above, it is necessary to irradiate the laser in a state in which the bonding end faces are in close contact with no gap.

[0006] However, due to a problem in the production of a molded warp or the like,
A gap is almost inevitably present between the joining end faces of the permeable resin material and the absorbent resin material. The presence of such a gap makes heat transfer from the joining end face of the absorbent resin material to the joining end face of the transparent resin material insufficient or impossible, and causes problems such as a decrease in joining strength and an inability to join.

Therefore, in order to ensure sufficient bonding strength and the like,
Conventionally, a method of using a pressing jig to bring the above joined end surfaces into close contact with each other and then irradiating a laser beam has been used.

[0008]

However, there is a problem that the method using the pressing jig cannot easily cope with a hollow part or a complicated-shaped part. For example,
When laser welding a three-dimensional pipe consisting of two parts,
If pressure is not applied from all angles by a jig adapted to the curved surface of the component shape, a uniform load is not applied between the joining end faces, and thus it is extremely difficult to reduce the gap on the entire joining end face.

In addition, since laser irradiation is performed in a state where the pressing jig is arranged, there is also a problem that the irradiation angle and the irradiation position are limited by the pressing jig.

The present invention has been made in view of the above-mentioned circumstances, and a resin component laser capable of obtaining a sufficient bonding strength without using a pressing jig even if a gap exists between bonding end faces. An object of the present invention is to provide a welding method.

[0011]

According to the present invention, there is provided a laser welding method for a resin component, which comprises the steps of:
An arranging step of making the joining end faces of the absorptive resin material having an absorptivity to the laser light opposite to each other, and irradiating the laser light from the permeable resin material side to form the permeable resin material And a laser welding method for a resin part, comprising: an irradiating step of heating and melting the joining end surfaces of the absorbent resin material to each other and welding them, and integrally joining the transparent resin material and the absorbent resin material. In the irradiating step, the laser beam may be irradiated while at least one end of the joint end face around the joint end face is set in a reduced pressure atmosphere.

In a preferred aspect, in the irradiating step, a pressure difference is provided between the one end and the other end of the joining end surface by setting only one end of the joining end surface around the joining end surface to a reduced pressure atmosphere. Can be.

[0013] In a preferred aspect, the permeable resin material and the absorbent resin material form a hollow body by joining the joining end faces, and the inside of the hollow body is depressurized in the irradiation step. Atmosphere can be.

In a preferred aspect, in the irradiating step, a non-irradiated portion which is not irradiated with the laser beam is provided at an end portion of the joining end surface of the absorptive resin material which is set to a reduced pressure atmosphere. Can be.

In a preferred aspect, a joining end of the transparent resin material is softened by internal heat generated by the transmission of the laser beam and can be deformed to a reduced-pressure atmosphere side. A receiving surface facing the direction in which the transparent resin material is deformed can be provided on the end surface. In this case, it is preferable that the joining end of the transparent resin material be thinner than other portions other than the joining end.

In a preferred aspect, in the irradiating step, a heat spot portion capable of absorbing a laser beam more than other portions of the joining end face is provided on a part of the joining end face of the absorbent resin material. Can be provided.

In a preferred aspect, the transmissive resin material has a high transmissive portion having a laser light transmittance higher than other portions, and the heat spot portion is provided with the laser light through the high transmissive portion. May be used as the high transmission irradiating section.

[0018] In a preferred aspect, the heat spot portion may be a direct irradiating portion to which the laser light is directly irradiated without passing through the transparent resin material.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser welding method for a resin part according to the present invention comprises the steps of: joining a bonding end of a transparent resin material that is permeable to laser light as a heat source; An arranging step in which a joining end face of a certain absorbent resin material and a joining end face thereof are opposed to each other, and the laser light irradiation from the transparent resin material side causes the joining end face of the transparent resin material and the absorbent resin material to be joined; An irradiation step in which the transparent resin material and the absorptive resin material are joined together by heating and fusing them together.

In the disposing step, the joining end surfaces of the joining end portion of the transparent resin material and the joining end portion of the absorbent resin material face each other. At this time, while forming a small gap (approximately 0.1 to 0.3 mm) in whole or in part due to a molding warp or the like,
The joining end faces are entirely opposed to each other or are partially in contact with each other. It is a problem to be solved by the present invention to achieve a sufficient joining strength without using a pressing jig even if there is a gap, and this is an original function and effect of the present invention. If there is a gap that is too large in whole or in part, it is difficult to fill the gap and secure sufficient bonding strength according to the present invention.
If there is a large gap of about mm or more, the gap may be reduced as necessary using a pressing jig.

In the irradiating step, laser light is irradiated from the transparent resin material side toward the joining end face of the absorbent resin material. The laser light irradiated from the transparent resin material side passes through the inside of the joint end of the transparent resin material, reaches the joint end surface of the absorbent resin material, and is absorbed. As a result of the laser light absorbed on the joining end face of the absorbent resin material being accumulated as energy, the joining end face of the absorbent resin material is heated and melted. At this time, if at least one end of the joining end face around the joining end face is in a reduced-pressure atmosphere, the molten resin at the joining end face of the absorbent resin material can flow toward the reduced-pressure atmosphere. For this reason, even if a gap partially exists between the joining end face of the permeable resin material and the joining end face of the absorbent resin material, the gap can be filled with the flowing molten resin. If the gap is filled with the molten resin in this manner, heat transfer from the joining end face of the absorbent resin material to the joining end face of the permeable resin material is reliably performed via the molten resin, so that the joining end face of the permeable resin material also Heating and melting can be sufficiently performed. Therefore, problems such as insufficient melting of the transparent resin material due to the gap or reduction in bonding strength due to unmelting can be solved. Therefore, according to the laser welding method of the present invention, even if there is a gap between the joining end surfaces, it is possible to obtain sufficient joining strength without providing a separate pressing jig. Further, since there is no gap between the joining end faces, the airtightness and liquid tightness are also improved.

In the joint thus obtained, the joining end faces are melted and joined, and between the joining end faces, a state in which both resins constituting both members are melted and enter each other and become entangled is formed. As a result, it has a strong bonding state and high bonding strength and pressure resistance.

Further, in the laser welding method of the present invention, since there is no need to separately arrange a pressing jig, the pressing jig does not limit the irradiation angle and the irradiation position of the laser beam. The degree of freedom such as the light irradiation angle is increased.

Here, the transparent resin material is not particularly limited as long as it has thermoplasticity and has a transmittance of a predetermined value or more to a laser beam as a heating source. For example, nylon 6 (PA6) or nylon 66 (P
A66) and other polyamides (PA) and polyethylene (P
E), polypropylene (PP), styrene-acrylonitrile copolymer, polyethylene terephthalate (PE
T), polystyrene, ABS, acrylic (PMME),
Examples thereof include polycarbonate (PC) and polybutylene terephthalate (PBT). If necessary, a reinforcing fiber such as glass fiber or carbon fiber or a coloring material may be used. However, as will be described later, the permeable resin material has a laser beam at the bonding end of the permeable resin material depending on the thickness at the bonding end (transmission distance of laser light), the wavelength of laser light used as a heating source, and the like. It is preferable to use a material having a laser light absorption property that is softened by internal heat generated by light transmission and deformed toward a reduced pressure atmosphere side.

The absorbent resin material is not particularly limited as long as it has thermoplasticity and has a predetermined or higher absorptivity to laser light as a heating source. For example, polyamide (PA) such as nylon 6 (PA6) or nylon 66 (PA66), polyethylene (PE), polypropylene (PP), styrene-acrylonitrile copolymer, polyethylene terephthalate (PET), polystyrene,
ABS, acrylic (PMME), polycarbonate (P
C), polybutylene terephthalate (PBT) or the like mixed with a predetermined coloring material such as carbon black, a dye or a pigment. In addition, what added the reinforcing fiber, such as glass fiber and carbon fiber, may be used as needed.

The combination of the permeable resin and the non-permeable resin is a combination of mutually compatible resins. Such combinations include combinations of resins of the same type, such as nylon 6 and nylon 66, a combination of nylon 6 and nylon 66, and a combination of PET and PET.
C and a combination of PC and PBT.

The type of laser light used as the above-mentioned heating source depends on the absorption spectrum and thickness (transmission distance of laser light) of the transparent resin material that transmits the laser light. Those having a wavelength such that the transmittance is equal to or more than a predetermined value are appropriately selected. For example, YAG: Nd
A 3+ laser (wavelength of laser light: 1060 nm) or a semiconductor laser (wavelength of laser light: 500 to 1000 nm) can be used.

Further, irradiation conditions such as laser output, irradiation density and processing speed (moving speed) can be appropriately set according to the type of resin and the like.

The shape of the permeable resin material and the absorptive resin material and the joining form of the two resin materials are not particularly limited. One by joining the joining end surfaces of the joining end portions of the permeable resin material together, or by joining the joining end surfaces of the joining end portions of the permeable resin material and the absorbent resin material consisting of the divided body of the predetermined shape A hollow body such as a box-shaped body or a tubular body may be used as a target.

In the above-mentioned irradiation step, the position or range where the depressurized atmosphere is formed around the joining end face of the transparent resin material and the absorbent resin material is that at least one end of the joining end face around the joining end face is depressurized atmosphere. The material is not particularly limited as long as it is set, and can be appropriately set in accordance with the shapes of the permeable resin material and the absorbent resin material, the joining form of both resin materials, and the like.

For example, by irradiating a laser beam in a state where the transparent resin material and the absorbent resin material are arranged in a reduced-pressure atmosphere such as in a reduced-pressure furnace, the entire area around the joint end surface may be set to a reduced-pressure atmosphere. In this case, the molten resin heated and melted at the joining end face of the absorbent resin material flows toward the entire peripheral edge of the joining end face.

However, from the viewpoint of reliably filling the gap with the molten resin over the entire joint end face, only one end of the joint end face around the joint end face is set to a reduced pressure atmosphere and the one end side and the other end of the joint end face are set to the reduced pressure atmosphere. It is preferable to provide a pressure difference between. By doing so, the molten resin flows only in one direction from the other end of the joining end face to the one end side (pressure-reduced atmosphere side) on the joining end face, and the gap in the entire joining end face is more uniformly filled with the molten resin. be able to.

More specifically, when the joining end surfaces of the permeable resin material made of a plate material or the like and the joining end portion of the absorbent resin material are butt-joined to each other, only one surface side of the plate material or the like is suctioned. When a hollow body is integrally formed by joining the joining end surfaces of the joining end portion of the permeable resin material and the joining end portion of the absorbent resin material, etc. The pressure can be reduced under such conditions. When the inside of the hollow body is set to a reduced pressure atmosphere,
Due to the suction action, the adhesion between the joining end faces of the permeable resin material and the absorbent resin material is improved, so that the welding strength can be effectively improved.

In the case where only one end of the joining end face around the joining end face is set to a reduced pressure atmosphere and a pressure difference is provided between the one end side and the other end side of the joining end face, the joining of the permeable resin material is performed. The end portion is softened by internal heat generated by the transmission of the laser beam and can be deformed to the reduced pressure atmosphere side, and the bonding end surface of the transparent resin material is deformed on the bonding end surface of the absorbent resin material. It is preferable to provide a receiving surface that faces in the direction of movement.
By doing so, the joint end of the transparent resin material softened by internal heat generation during laser irradiation is deformed toward the reduced-pressure atmosphere side (the reduced-pressure suction side), and the deformed joint end faces the receiving surface facing this deformation direction. Can be reduced. For this reason, it is possible to more reliably fill the gap between the joining end surfaces with the molten resin. Further, when the deformation amount of the joint end of the transparent resin material is large, the deformed joint end can be received and supported by the receiving surface.
If the deformed joint end is received and supported by the receiving surface, the adhesion between the two is improved, which is advantageous in improving the welding strength.

In order to make the joining end portion of the transparent resin material softer due to the internal heat generated by the transmission of the laser beam and be deformable toward the reduced-pressure atmosphere, for example, the material constituting the transparent resin material is used. What is necessary is just to appropriately set the laser light absorption characteristics of the device itself, the thickness of the joint end (the transmission distance of the laser light), and the like.
In addition, it is needless to say that the joining end portion of the transmissive resin material must have sufficient transparency to the laser beam so that the energy required for laser welding can reach the joining end surface of the absorbing resin material. .

Further, a pressure difference is provided between one end and the other end of the joining end face, and the joining end of the transparent resin material is softened by internal heat generated by the transmission of the laser beam and may be deformed to a reduced pressure atmosphere side. In the case where the receiving surface is provided on the joining end surface of the absorbent resin material, it is preferable to make the joining end portion of the permeable resin material thinner than other portions other than the joining end portion. . By reducing the thickness of the joining end, the joining end is more easily deformed, so that the gap between the receiving surface and the joining end is reduced, or the two are brought into contact with each other. This is advantageous in improving the adhesiveness between them. In addition, by locally reducing the thickness of the joint end, the above-described effect can be exhibited while maintaining the rigidity required in the main body other than the joint end. Further, by reducing the thickness of the joint end, the transmission distance of the laser beam transmitted through the joint end is reduced, so that the laser light transmittance at the joint end increases, and more laser light energy is transmitted. It can reach the joining end face of the absorbent resin material. For this reason, the amount of molten resin at the joint end surface of the absorptive resin material can be increased without improving the output or irradiation density of the laser light. Therefore, it is advantageous in filling the gap with the molten resin, and also advantageous in cost.

The receiving surface provided on the joining end face of the absorbent resin material faces the side opposite to the reduced-pressure atmosphere side (the reduced-pressure suction side) and moves toward the tip end of the joining end portion of the absorbent resin material. Thus, an inclined surface can be formed which is inclined so as to gradually approach the reduced pressure atmosphere side. In this case, an inclined surface that can be brought into contact with the absorbent resin material in alignment with the inclined surface can also be provided on the joining end surface of the transparent resin material.

Further, in the irradiation step, a non-irradiated portion (flow stop portion) to which laser light is not applied may be provided at an end of the joining end surface of the absorbent resin material on the side where the reduced pressure atmosphere is provided. preferable. The non-irradiated portion provided on the joining end face of the absorbent resin material and not irradiated with laser light has a lower temperature than other portions of the joining end face irradiated with laser light. For this reason, by providing a non-irradiation portion at the end on the side where the reduced-pressure atmosphere is provided, the flow of the molten resin flowing in the reduced-pressure suction direction stops at the non-irradiation portion due to the action of surface tension and cooling. Therefore, it is possible to prevent the generation of burrs based on the reduced pressure suction.

As described above, when the entire area around the joining end face is set to a reduced-pressure atmosphere, the non-irradiated portion can be provided on the entire peripheral edge of the joining end face of the absorbent resin material.

In addition, in the above-mentioned irradiation step, it is preferable to provide a heat spot portion capable of absorbing more laser light on a part of the joining end face of the absorbent resin material than other portions of the joining end face. . Since the heat spot portion provided on the joining end surface of the absorbent resin material absorbs more laser light, the temperature is higher than other portions of the joining end surface other than the heat spot portion, and the temperature is higher, and more This produces molten resin. For this reason, the heat spot serves as a supply source of the molten resin, which is advantageous for filling the gap between the joining end faces with the molten resin. Therefore, even when a larger gap exists between the joining end faces, the gap can be reliably filled with the molten resin, and the joining strength can be improved.

In order to more effectively exert the effect of the heat spot portion, the heat spot portion is attached to an end of the joining end surface of the absorbent resin material opposite to the side where the reduced pressure atmosphere is formed. Preferably, it is provided. By doing so, all of the molten resin generated at the heat spot
It can be used to fill the gap between the joining end faces, and it is more advantageous to fill the gap with the molten resin.

The heat spot portion is provided with a high transmission portion having a laser light transmittance higher than that of the other portions at the joining end portion of the transparent resin material, and the laser beam is irradiated through the high transmission portion. It can also be formed by a high transmission irradiation part. Such a high transmission portion can be formed by shortening the transmission distance of the laser light as compared with other portions. For example, while the joining end portion of the permeable resin material is provided with a first convex portion in which the decompression suction side is notched obliquely and the tip portion is cut off while leaving a step portion on the base end side of the decompression suction side, A second convex portion in which the opposite side to the decompression suction side is notched diagonally and the tip is cut off while leaving a stepped portion on the base end side opposite to the decompression suction side at the joint end of the absorbent resin material. By providing the tip portion of the first convex portion as a highly transparent portion, the base portion of the second convex portion which can be brought into contact with the tip portion of the first convex portion in alignment with the first convex portion is provided. The step part can be a high transmission irradiation part. The distal end of the first convex portion as a high transmission portion formed in this way has a shorter laser light transmission distance than other portions of the first convex portion, so that the laser light transmittance is lower in other portions. Higher than. Therefore, the laser light that passes through the high-transmitting portion and reaches the joining end face of the absorbent resin material is different from the laser light that passes through other portions of the first convex portion and reaches the joining end face of the absorbing resin material. The energy also increases, so that the high-transmission portion irradiated with the laser beam transmitted through the high-transmission portion has a higher temperature than other portions, and can be a supply source of the molten resin.

Further, the heat spot portion can be formed by a direct irradiation portion to which laser light is directly irradiated without passing through a transparent resin material. For example, while providing a fitting convex portion at the joining end portion of the permeable resin material, providing a fitting concave portion capable of fitting with the fitting convex portion at the joining end portion of the absorbent resin, and
Side wall portion of the fitting concave portion (side wall portion on the side opposite to the reduced pressure atmosphere side)
By providing a gap between the inner surface of the side wall and the outer surface of the fitting convex portion facing the inner surface, the inner surface of the side wall portion can be directly used as the irradiation portion. The laser light can be directly applied to the inner surface of the side wall portion via the wedge-shaped gap between the inner surface of the side wall portion thus formed and the outer surface of the fitting convex portion facing the inner surface.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) This embodiment shown in FIGS. 1 to 3 embodies the invention described in claim 1, 2, 3, 4, 5 or 6, and is made of resin having an inlet. The present invention is applied to the manufacture of a tank.

This resin tank is vertically divided into two parts, and is composed of a transparent resin material 1 as an upper first divided body and an absorbent resin material 2 as a lower second divided body. It is a hollow body, and the joining end 10 of the transparent resin material 1 and the joining end 20 of the absorbent resin material 2 are integrally joined by laser welding. In addition, the transparent resin material 1 is provided with an injection port 1a.

The transmissive resin material 1 has such a property that the energy required for laser welding can reach the joint end face of the absorptive resin material 2 with respect to the laser light, and the internal heat generated by the transmission of the laser light. It has an absorptivity to laser light to such an extent that it can be softened and deformed to the reduced pressure atmosphere side. Specifically, in this example, a reinforced plastic obtained by adding an appropriate amount of glass fiber as a reinforcing material to PA66 and carbon black as an auxiliary agent (coloring material) to PA66 was used. The laser light transmittance at the joint end 10 of the transparent resin material 1 is about 10 to 70%.

The absorbing resin material 2 is capable of absorbing laser light as a heating source. Specifically, in the present example, a reinforced plastic was used in which 30 wt% of glass fiber as a reinforcing material and carbon black as an auxiliary agent (coloring material) were appropriately added to PA66.

The laser beam used for irradiation is YAG:
Nd3 + laser (wavelength: 1060 nm). Also,
Both the permeable resin material 1 and the absorbent resin material 2 are PA6
6 is a base resin, which are compatible with each other.

As shown in FIG. 2, the joining end portion 10 of the permeable resin material 1 has a step at the base end side (upper side in FIG. 2) inside the hollow body (right side in FIG. 2, the same applies hereinafter). While the inside of the hollow body and the outside of the hollow body (the left side in FIG. 2, the same applies hereinafter) are cut out in a tapered shape, the leading end is cut off, and gradually reduces to the leading side (the lower side in FIG. 2). It is constituted by a fitting projection 11 formed in a protruding shape. The fitting projection 11 includes a first distal end surface 11a, inner and outer tapered outer surfaces 11b and 11c of the hollow body, and an inner inner stepped surface intersecting the base end of the inner tapered outer surface 11b of the hollow body. 11d
And In addition, the tapered outer surface 11 inside the hollow body
b has a steeper inclination angle than the outer tapered outer surface 11c,
And the length is lengthened. Note that this fitting projection 11
Are each tapered outer surface 11b, 11c and inner stepped surface 11d
The thickness of the hollow body is made thinner than other parts of the permeable resin material 1 by the amount that the inside and outside of the hollow body are cut off.

On the other hand, the joining end portion 20 of the absorbent resin material 2 is formed so as to gradually expand and protrude toward the distal end side (upward in FIG. 2), and can be fitted to the fitting convex portion 11. Fitting recess 2
1 is provided. The fitting recess 21 has a bottom surface 21a aligned with the first distal end surface 11a, inner and outer tapered inner surfaces 21b and 21c of the hollow body aligned with the tapered outer surfaces 11b and 11c, respectively.
The second inner side of the hollow body, which intersects the tip of the tapered inner surface 21b inside the hollow body and is aligned with the inner stepped surface 11d.
And a tip surface 21d.

The first end surface 11 of the fitting projection 11
a, each tapered outer surface 11b, 11c and inner stepped surface 11d
Constitute a joint end face of the transparent resin material 1, the bottom face 21a of the fitting recess 21, the tapered inner faces 21b,
1c and the second end face 21d as a whole, the absorbent resin material 2
Are formed. Further, the tapered inner surface 21b inside the hollow body of the fitting concave portion 21 faces the side opposite to the depressurized atmosphere side (the inside of the hollow body) and heads toward the distal end side of the joining end portion 20 of the absorbent resin material 2. As a result, the tapered inner surface 21b is formed to be inclined so as to gradually approach the reduced pressure atmosphere side.
Function as a receiving surface facing in the direction in which the fitting projection 11 is deformed. Further, in the irradiation step described later, the fitting recess 2 is used.
The first second end face 21d is provided at the end on the reduced-pressure atmosphere side of the end of the joining end face of the absorbent resin material 2, and functions as a non-irradiated portion not irradiated with laser light.

The fitting projections 11 of the transparent resin material 1 and the fitting recesses 21 of the absorbent resin material 2 are fitted together, and the first front end surface 11a and the bottom surface 21a are connected to the inner tapered outer surface. The outer tapered outer surface 11c and the outer tapered outer surface 21c are integrally joined to each other by laser welding.

The resin tank of the present embodiment having the above configuration was manufactured as follows.

(Arrangement Step) First, the transparent resin material 1 and the absorbent resin material 2 were each formed into a predetermined shape by injection molding. The joining end face of the joining end 10 of the transparent resin material 1 and the joining end face of the joining end 20 of the absorbent resin material 2 face each other.
1 and the fitting recess 21 of the absorbent resin material 2 were fitted (FIG. 2).
State).

At this time, as shown in FIG. 2, the joining end face of the permeable resin material 1 and the joining end face of the absorbent resin material 2 are formed by a warp or the like of the permeable resin material 1 and the absorbing resin material 2. A small gap (about 0.3 mm) S is formed on the entire surface.

Then, as shown in FIG. 1, a vacuum pump 4 was connected to the inlet 1 a of the permeable resin material 1 via a hose 3. (Irradiation step) With the vacuum pump 4 operated and the interior of the hollow body in a reduced pressure atmosphere (vacuum state), using the laser torch 5, The laser beam 6 was irradiated from the outside of the hollow body toward the transparent resin material 1 toward the tapered inner surfaces 21b and 21c (see FIG. 3). At this time, the fitting recess 2 as a non-irradiation portion
The first second end face 21d was not irradiated with the laser beam 6.

The laser beam used was a YAG-neodymium laser beam (wavelength: 1060 nm). Irradiation conditions: output: 200 to 400 W, processing speed: 5 m / min
And

By the above-mentioned laser irradiation, the entire inner surface of the fitting recess 21, that is, the bottom surface 21 a and the respective tapered inner surfaces 21 b are used while utilizing the repetition of reflection on the inner surface (the bottom surface 21 a and the respective tapered inner surfaces 21 b and 21 c) of the fitting recess 21. , 2
1c is irradiated with the laser beam 6 to heat and melt the first tip end surface 11a of the fitting protrusion 11 and the respective tapered outer surfaces 11b and 11c, and the bottom surface 21a of the fitting recess 21 and the respective tapered inner surfaces 21b and 21c. And welded and joined together.

In this irradiation step, since the inside of the hollow body is set in a reduced pressure atmosphere by the vacuum pump 4, the laser light 6
21 of the absorbent resin material 2 that has been irradiated and heated and melted
a, The molten resin on each of the tapered inner surfaces 21b and 21c can be caused to flow toward the reduced-pressure atmosphere. For this reason, even if a gap S exists between the joining end face of the transparent resin material 1 and the joining end face of the absorbent resin material 2, the gap S can be filled with the flowing molten resin.

In particular, in this embodiment, only one end of the joint end face (only the inside of the hollow body) around the joint end face (outside and inside of the hollow body) is set to a reduced pressure atmosphere, Inside) and the other end of the joining end face (outside the hollow body)
Since the pressure difference is provided between the two ends, the flow of the molten resin only in one direction from the other end to the one end of the joining end surface occurs, and the gap S over the entire joining end surface can be uniformly filled with the molten resin.

When the gap S is filled with the molten resin, the bottom surface 21 a of the absorbent resin material 2,
b and 21c, the first end face 11a of the transparent resin material 1;
Since heat transfer to each of the tapered outer surfaces 11b and 11c is reliably performed via the molten resin, the permeable resin material 1 can be sufficiently heated and melted. Therefore, the gap S
This can solve the problems such as insufficient melting of the transparent resin material 1 or a decrease in bonding strength due to unmelting of the transparent resin material 1. Therefore, according to the laser welding method of the present embodiment, even if there is a gap S between the joint end surfaces, it is possible to obtain sufficient joint strength without providing a separate pressing jig. In addition, since the gap S between the joining end faces is eliminated, the airtightness and liquid tightness are improved. In particular, in this embodiment, since the inside of the hollow body is suctioned under reduced pressure, the suction action can improve the adhesion between the joining end face of the permeable resin material 1 and the joining end face of the absorbent resin material 2. it can.

In the joining portion thus obtained, the joining end faces are melted and joined, and between the joining end faces, a state in which both resins constituting both members are melted into each other and entangled with each other is formed. As a result, it has a strong bonding state and high bonding strength and pressure resistance.

In this embodiment, in addition to the joining of the fitting projections 11 and the fitting recesses 21 by laser welding, the fitting of the fitting projections 11 and the fitting recesses 21 and the transmission of the transparent resin material are performed. 1
Inner stepped surface 11d and second end surface 21 of absorbent resin material 2
Since it is a structurally strong joint due to engagement with d, it has a higher joint strength and pressure resistance, and is advantageous in suppressing deformation such as warpage due to reduced pressure suction.

Further, in the laser welding method of this embodiment,
Since there is no need to separately arrange a pressing jig, the pressing jig does not limit the irradiation angle and the irradiation position of the laser light 6, and the degree of freedom such as the irradiation angle of the laser light 6 is increased.

In addition, the transparent resin material 1 in this embodiment
Can be deformed toward the reduced pressure suction side due to softening due to the transmission of the laser light 6, and face the bonded end face of the absorbent resin material 2 in the deformation direction of the bonded end 10. An inner tapered inner surface 21b as a receiving surface is provided. For this reason, in the irradiation step, the portion of the transparent resin material 1 through which the laser beam 6 has passed, that is, the entire fitting convex portion 11 and the portion above the fitting convex portion 11 are softened due to internal heat generation, and are drawn into the hollow body by suction under reduced pressure. It deforms and approaches the tapered inner surface 21b of the fitting recess 21 as the receiving surface. In particular, the fitting convex portion 11 in the present embodiment is easily deformed by the reduced thickness compared to other portions. Thereby, the fitting protrusion 11
The gap S between the tapered outer surface 11b inside the inside and the tapered inner surface 21b inside the fitting recess 21 becomes smaller. For this reason, it is possible to more reliably fill the gap S between the joining end surfaces with the molten resin.

Further, since the fitting protrusion 11 is locally thinned, the rigidity required in the main body other than the fitting protrusion 11 of the transparent resin material 1 is maintained while maintaining the rigidity. Such effects can be exerted. Further, the transmission distance of the laser light 6 is shortened by the thickness of the fitting protrusion 11, and the transmittance of the laser light in the fitting protrusion 11 increases, thereby absorbing more laser light energy. It can reach the joining end face of the conductive resin material 2. For this reason, the amount of molten resin at the joint end face of the absorbent resin material 2 can be increased without improving the output, irradiation density, and the like of the laser light 6. Therefore, it is advantageous in filling the gap S with the molten resin, and also advantageous in cost.

Further, in the present embodiment, in the irradiation step, the non-irradiated portion where the laser beam 6 is not irradiated is applied to the end of the joining end surface of the absorptive resin material 2 on the side where the reduced pressure atmosphere is formed. A second tip surface 21d is provided. For this reason, by the action of surface tension and cooling at the non-irradiated portion, the molten resin flowing in the reduced-pressure suction direction can be retained at the non-irradiated portion. Therefore, it is possible to prevent the generation of internal burrs due to reduced pressure suction.

(Embodiment 2) This embodiment shown in FIGS. 4 and 5 embodies the invention described in claims 1, 2, 3, 4, 5, 6, 7 or 8. In Example 1, the shape and the joining form of the joining end 10 of the transparent resin material 1 and the joining end 20 of the absorbent resin material 2 were changed.

The joint end 10 of the permeable resin material 1 in this embodiment is located on the base end side inside the hollow body (right side in FIG. 4, the same applies hereinafter) and outside the hollow body (left side in FIG. 4, the same applies hereinafter). The inside of the hollow body is cut out in a tapered shape while leaving a step at each (upper side in FIG. 4), and the front end is cut off, and gradually contracts and protrudes to the front side (lower side in FIG. 4). The first projection 12 is formed in a shape. That is, the first convex portion 12 is made thinner than the other portions, and the transmission distance of the laser beam 6 is shortened. The first convex portion 12 includes a first distal end surface 12a, a first tapered surface 12b facing the inside of the hollow body, and an inner stepped surface 12c provided inside and intersecting the base end of the first tapered surface 12b. , A first outer stepped surface 12d provided on the outside.

On the other hand, the joining end 20 of the absorbent resin material 2
The outer side of the hollow body is cut out in a tapered shape while leaving a step on the outer base end side (lower side in FIG. 4) of the hollow body, and the front end is cut off, and the front end side (upper side in FIG. 4) The second convex portion 22 is formed in a shape that gradually reduces and projects. The second convex portion 22 has a second outer stepped surface 22a aligned with the first distal end surface 12a and a second tapered surface 22b facing the outside of the hollow body and aligned with the first tapered surface 12b. , A second tip surface 22c that intersects the tip of the second tapered surface 22b and that is aligned with the inner stepped surface 12c.

The first end surface 1 of the first convex portion 12
2a, the first tapered surface 12b, and the inner stepped surface 12c together form a joint end surface of the transparent resin material 1;
Second outer stepped surface 22 a of convex portion 22, second tapered surface 22
b and the entirety of the second front end face 22c constitute a joint end face of the absorbent resin material 2. In the irradiation step, the second tapered surface 22 b functions as a receiving surface facing the direction in which the first convex portion 12 of the transparent resin material 1 is deformed, and the second front end surface of the second convex portion 22. 22c functions as a non-irradiation part.

Then, the first convex portion 12 of the transparent resin material 1 is formed.
And the second convex portions 22 of the absorbent resin material 2 are engaged with each other, and the first distal end surface 12a and the second outer stepped surface 22a
And the first tapered surface 12b and the second tapered surface 22b are integrally joined by laser welding.

The other structure is the same as that of the first embodiment.

In this embodiment, the first convex portion 12 of the transparent resin material 1 is actively thinned by the cutout provided with the first outer stepped surface 12d. For this reason,
Even if the degree of softening is smaller, the first convex portion 12 can be deformed toward the reduced pressure atmosphere.

Further, in this embodiment, the thickness of the first convex portion 12 of the transparent resin material 1 is gradually reduced toward the front end, and the front end of the first convex portion 12 is The transmission distance of the laser light 6 is shorter than that of the base end. For this reason,
In the irradiation step, the tip 12e of the first convex portion 12
The tip 12e functions as a high-transmitting portion whose laser light transmittance is higher than that of the other portions.
The second convex portion 2 to which the laser beam transmitted through the portion reaches
The second outer stepped surface 22a functions as a high transmission irradiation portion as a heat spot portion.

Therefore, the second outer stepped surface 22a of the second convex portion 22 functioning as a heat spot portion absorbs the laser light 6 more, so that the second outer stepped surface 22a is in contact with other portions of the joining end surface other than the heat spot portion. In comparison, the temperature is higher,
Produces more molten resin. For this reason, the second outer stepped surface 22a as the heat spot portion serves as a supply source of the molten resin, which is advantageous for filling the gap S between the joining end surfaces with the molten resin. In particular, in this embodiment, the end of the joining end surface of the absorbent resin material 2 on the opposite side (outside of the hollow body) and the end on the opposite side (outside of the hollow body) as a heat spot portion Since the second outer stepped surface 22a is provided, it is possible to use all of the molten resin generated in the heat spot portion to fill the gap S between the joining end surfaces. Therefore, even when there is a larger gap S between the joining end faces, the gap S can be reliably filled with the molten resin, and the joining strength can be improved.

Other functions and effects are the same as those of the first embodiment.

(Embodiment 3) This embodiment shown in FIG. 6 embodies the invention described in claims 1, 2, 3, 4, 5, 6, 7 or 9. The shape of the fitting recess 21 forming the joining end 20 of the absorbent resin material 2 is slightly changed.

That is, in the present embodiment, the outer tapered inner surface 21e of the fitting concave portion 21 is more widely opened outward.
A wedge-shaped gap is formed between the outer tapered inner surface 21 e and the outer tapered outer surface 11 c of the fitting projection 11.
Therefore, in the irradiation step, the laser beam 6 is directly irradiated to the outer tapered inner surface 21e from the wedge-shaped gap. Therefore, the outer tapered inner surface 21e functions as a direct irradiation unit to which the laser beam 6 is directly irradiated without transmitting through the fitting protrusion 11 of the transparent resin material 1.

The other structure is the same as that of the first embodiment.

Therefore, since the outer tapered inner surface 21e of the fitting concave portion 21 functioning as a heat spot portion absorbs the laser beam 6 more, the temperature is lower than that of other portions of the joining end surface other than the heat spot portion. And become a supply source of molten resin. Further, similarly to the second embodiment, of the ends of the joining end surfaces of the absorbent resin material 2, the ends on the opposite side (outside of the hollow body) and the side on the opposite side (outside of the hollow body),
Since the outer tapered inner surface 21e as the heat spot portion is provided, all of the molten resin generated in the heat spot portion can be used to fill the gap S between the joining end surfaces. Therefore, even when there is a larger gap S between the joining end faces, the gap S can be reliably filled with the molten resin, and the joining strength can be improved.

Other functions and effects are the same as those of the first embodiment.

[0084]

As described above in detail, in the laser welding method for resin parts according to the present invention, in the irradiation step, the laser beam irradiation is carried out while reducing the pressure around at least one end of the joint end surface around the joint end surface. Since it is performed, the molten resin at the joining end face of the absorbent resin material is caused to flow toward the reduced-pressure atmosphere side,
The gap between the joining end faces can be filled with the molten resin. Therefore, it is possible to solve problems such as insufficient bonding of the permeable resin material due to the gap between the bonding end faces or a reduction in bonding strength due to unmelting, and without providing a separate pressing jig, sufficient bonding strength. It is possible to obtain.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a laser welding method for a resin component according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of the first embodiment of the present invention, illustrating an arrangement step of making bonding end surfaces of a bonding end portion of a transparent resin material and a bonding end portion of an absorbent resin material face each other.

FIG. 3 relates to Example 1 of the present invention, and is an irradiation step of heating and melting the joining end surfaces of the joining end portion of the transparent resin material and the joining end portion of the absorbent resin material by laser beam irradiation to weld them. It is principal part sectional drawing explaining.

FIG. 4 is a cross-sectional view of a principal part for explaining an arrangement step in which bonding end surfaces of a bonding end portion of a transparent resin material and a bonding end portion of an absorbent resin material face each other according to the second embodiment of the present invention.

FIG. 5 relates to a second embodiment of the present invention, in which a laser beam is applied to heat and melt a joint end surface between a joint end portion of a transmissive resin material and a joint end portion of an absorptive resin material to weld them. It is principal part sectional drawing explaining.

FIG. 6 relates to a third embodiment of the present invention, in which a laser beam is applied to heat and melt a joint end surface between a joint end portion of a transmissive resin material and a joint end portion of an absorbent resin material to weld them. It is principal part sectional drawing explaining.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transmissive resin material 2 ... Absorbing resin material 4 ... Vacuum pump 5 ... Laser torch 6 ... Laser beam 10, 20 ... Joining end part 11 ... Fitting convex part 21 ... Fitting concave part 11a, 11b, 11c, 11d ... Joining End faces (11a ...
1st tip surface, 11b ... inner taper outer surface, 11c ... outer taper outer surface, 11d ... inner stepped surface) 21a, 21b, 21c, 21d, 21e ... joining end surface (21a ... bottom surface, 21b ... inner taper inner surface (receiving surface)) ,
21c: outer tapered inner surface, 21d: second distal end surface (non-irradiated portion), 21e: outer tapered inner surface (directly irradiated portion as a heat spot portion) 12: first convex portion 22: second convex portion 12a, 12b, 12c: joining end face (12a: first distal end face, 12b: first tapered face, 12c: inner stepped face) 22a, 22b, 22c: joining end face (22a: second outer stepped face (as a heat spot portion) High transmission irradiator), 2
2b: second tapered surface (receiving surface), 22c: second distal end surface (non-irradiated portion) 12e: high transmission portion S: gap M: molten resin

Continued on the front page (72) Inventor Natsuhiko Katahira 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 4E068 BA00 CJ09 DA06 DB10 4F211 AA11 AA29 AD05 AM28 TA01 TC09 TD07 TD09 TH18 TN27

Claims (9)

[Claims] 1. A joining end face of a joining end of a transmissive resin material that is permeable to laser light as a heating source and a joining end of an absorptive resin material that absorbs the laser light. By disposing the laser light from the permeable resin material side and arranging the permeable resin material side to each other, the joining end faces of the permeable resin material and the absorptive resin material are heated and melted and welded, and the permeable resin material is welded. A laser welding method for a resin component, comprising: an irradiating step of integrally joining the material and the absorbent resin material. In the irradiating step, at least one end of the joining end face around the joining end face is set to a reduced pressure atmosphere. A laser welding method for a resin component, wherein the laser beam is irradiated while performing the laser irradiation. 2. In the irradiating step, a pressure difference is provided between the one end side and the other end side of the bonding end surface by setting only one end side of the bonding end surface around the bonding end surface to a reduced pressure atmosphere. The method for laser welding resin parts according to claim 1. 3. The permeable resin material and the absorptive resin material constitute a hollow body by joining the joining end faces to each other, and the inside of the hollow body is set to a reduced pressure atmosphere in the irradiation step. 3. The method for laser welding resin parts according to claim 2, wherein: 4. The non-irradiated portion to which the laser beam is not applied is provided at an end of the absorbent resin material on the side of the decompressed atmosphere among the ends of the joining end surface in the irradiating step. The method for laser welding resin parts according to claim 1, 2, or 3. 5. A joining end portion of the transparent resin material is softened by internal heat generated by the transmission of the laser beam and can be deformed to a reduced pressure atmosphere side. 5. The laser welding method according to claim 2, wherein a receiving surface facing the deforming direction of the joint end is provided. 6. The laser welding method for a resin part according to claim 5, wherein a joining end of the transparent resin material is thinner than other portions other than the joining end. 7. In the irradiating step, a part of the joining end face of the absorbent resin material is provided with a heat spot portion capable of absorbing laser light more than other parts of the joining end face. 7. The method of claim 1, 2, 3, 4, 5 or 6.
A laser welding method for the resin component described in the above. 8. The transparent resin material has a high-transmitting portion having a laser light transmittance higher than other portions, and the heat spot is irradiated with the laser light through the high-transmitting portion. The laser welding method for a resin part according to claim 7, wherein the resin part is a high transmission irradiator. 9. The method according to claim 7, wherein the heat spot portion is a direct irradiation portion to which the laser light is directly irradiated without passing through the transparent resin material.