JP2002067165A - Resin molding - Google Patents

Abstract

[PROBLEMS] To reach and absorb more laser light to the contact surface of the non-transparent resin material by devising the shape at the contact end of the transparent resin material and the non-transparent resin material. To improve the bonding strength. SOLUTION: A first molding member 11 made of a transparent resin material that is transparent to a laser beam as a heating source, and a second molding made of a non-transparent resin material that is not transparent to the laser beam. The contact ends 11a and 12a of the members 11 and 12 are welded and joined by laser light irradiation from the transparent resin material side. By providing a concave portion 11c on the laser light incident surface at the contact end portion 11a of the first molding member 11 made of a transparent resin material, the transmission distance of the laser light transmitted through the transparent resin material is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product, and more particularly, to a resin material permeable to laser light and a non-permeable resin material not permeable to laser light. And a resin molded product integrally joined by laser welding.

[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, Japanese Patent Application Laid-Open No. 60-214931 discloses that after a transparent resin material that is permeable to laser light and a non-transparent resin material that is not permeable to the laser light, By irradiating a laser beam from the transparent resin material side, the contact surfaces of the transparent resin material and the non-transparent resin material are heated and melted, and a laser welding method of integrally joining the two is disclosed. I have.

In this laser welding method, the laser light transmitted through the transparent resin material reaches the contact surface of the non-transparent resin material and is absorbed, and the absorbed laser light is stored as energy. Is done. As a result, the contact surface of the non-transparent resin material is heated and melted, and the contact surface of the transparent resin material is heated and melted by heat transfer from the contact surface of the non-permeable resin material. In this state, if the contact surfaces of the permeable resin material and the non-permeable resin material are pressed together, they can be integrally joined.

[0005]

By the way, in the laser welding as described above, in order to ensure that the contact surfaces of the permeable resin material and the non-permeable resin material are welded to each other and to obtain a sufficient joining strength, The energy of the laser light needs to be sufficiently absorbed by the contact surface (absorption surface) of the non-transparent resin material.

However, depending on the type of the transparent resin material and the laser beam, and more specifically, depending on the laser beam transmittance of the transparent resin material and the wavelength of the laser beam used as a heating source, the non-transparent resin material may be used. There has been a problem that it is difficult to reach and absorb a sufficient amount of laser light on the contact surface.

[0007] The present invention has been made in view of the above circumstances, and by devising the shapes of the contact ends of the permeable resin material and the non-permeable resin material, the contact surface of the non-permeable resin material can be improved. It is a technical problem to be solved to provide a resin molded product that is advantageous for improving and improving bonding strength by arriving and absorbing a large amount of laser light.

[0008]

According to a first aspect of the present invention, there is provided a resin molded product, comprising: a transparent resin material that transmits laser light as a heating source; A non-transparent resin material, and abutting ends of the transparent resin material and the non-transparent resin material are welded and joined by irradiation of the laser light from the transparent resin material side. The article is characterized in that a recess is provided on the laser light incident surface at the contact end of the transparent resin material.

(2) The resin molded product according to the second aspect of the present invention is the resin molded product according to the first aspect, wherein a fitting recess is formed on the laser light absorbing surface at the contact end of the non-transparent resin material. And a fitting convex portion capable of fitting with the fitting concave portion is provided at the contact end portion of the transparent resin material.

(3) The resin molded product according to the third aspect is a transparent resin material that is permeable to laser light as a heating source and a non-transparent resin material that is not permeable to the laser light. Wherein the abutting ends of the permeable resin material and the non-permeable resin material are welded and joined by irradiation of the laser light from the permeable resin material side, A fitting convex portion is provided on the laser light absorbing surface at the contact end portion of the transparent resin material, and a fitting that can be fitted to the fitting convex portion at the contact end portion of the transparent resin material. A concave portion is provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A resin molded product according to the present invention comprises:
It is made of a non-transparent resin material that is not transparent to the laser light, and the contact ends of the transparent resin material and the non-transparent resin material are integrally joined by laser welding. This laser welding is performed by irradiating laser light from the transparent resin material side in a state where the contact ends of the transparent resin material and the non-transparent resin material are in contact with each other. The laser light emitted from the transparent resin material side passes through the transparent resin material, reaches the contact surface (absorption surface) of the non-transparent resin material, and is absorbed. As a result of the laser light absorbed by the contact surface of the non-transparent resin material being accumulated as energy, the contact surface of the non-transparent resin material is heated and melted, and the contact surface of the non-transparent resin material is heated. Then, the contact surface of the transparent resin material is heated and melted by the heat transfer. In this state, if the contact surfaces of the permeable resin material and the non-permeable resin material are pressed together, they can be integrally joined.

In the joint portion thus obtained, the joining surfaces are melted and joined, and between the joining surfaces, a state is formed in which the two resins constituting both molding members are melted and enter each other and become entangled. Therefore, it has a strong joining state and has high joining strength and pressure resistance.

Here, in the resin molded product according to the first aspect,
A concave portion is provided on the laser light incident surface at the contact end of the transparent resin material. The shape and size of the recess are not particularly limited. For example, a cross-sectional shape such as a substantially trapezoidal shape, a substantially semicircular shape, or a substantially triangular shape can be employed.

However, if the laser beam transmittance of the transparent resin material at the time of laser welding is 26% or more, the welding strength by laser welding can be remarkably improved.
Therefore, depending on the transparency of the resin used for the transparent resin material to the laser light, the wavelength of the laser light used as the heating source, and the like, at least a part of the laser light incident from the concave portion is 26% or more. To ensure the transmittance,
It is preferable to set the shape and size (transmission distance) of the recess. Note that the laser light transmittance refers to a percentage of the energy of the laser light transmitted through the transparent resin material with respect to the energy of the incident light.

Since the concave portion is provided on the laser light incident surface at the contact end of the transparent resin material, the transmission distance of the laser light through the transparent resin material is shortened by the concave shape. . For this reason, the energy loss of the laser beam during transmission through the transparent resin material is reduced.
Therefore, more laser light can reach and be absorbed by the contact surface of the non-transparent resin material, and the contact surfaces of the transmissive resin material and the non-transparent resin material are sufficiently heated and melted to perform laser welding. It is possible to improve the bonding strength.

Further, in the resin molded product according to claim 1, a fitting concave portion is provided in the laser light absorbing surface at the contact end portion of the non-transparent resin material, and the contact portion of the transparent resin material is provided. It is preferable to provide a fitting projection which can be fitted to the fitting recess at the contact end. The shape and size of the fitting concave portion and the fitting convex portion are not particularly limited.
The cross section may have a substantially trapezoidal shape, a substantially semicircular shape, a substantially triangular shape, or the like.

However, depending on the transparency of the resin used for the transparent resin material to the laser light, the wavelength of the laser light used as the heating source, etc., at least a part of the laser light reaching the fitting concave portion is 26%. It is preferable to set the shape and size (transmission distance) of the fitting concave portion and the fitting convex portion so that the above-described laser light transmittance can be secured.

As described above, if the fitting recess is provided in the non-transparent resin material and the fitting protrusion is provided in the transparent resin material, the fitting recess of the non-transparent resin material and the fitting of the transparent resin material are possible. Since the mechanical coupling force is applied between the permeable resin material and the non-permeable resin material by the concave-convex fitting with the convex portion, the bonding strength between the two can be further improved.

Also, the mechanical coupling force of the concave-convex fitting corrects the warp or the like at the contact end of the permeable resin material and the non-permeable resin material. The generation of a gap between the transparent resin material and the contact surface can be suppressed. For this reason, the heat generated on the contact surface of the non-transparent resin material is reliably transmitted to the contact surface of the transparent resin material, and the contact surface of the transparent resin material can be reliably heated and melted. Therefore, the contact surfaces of the transparent resin material and the non-transparent resin material can be reliably welded to each other by laser welding.

According to a third aspect of the present invention, there is provided a resin molded product, wherein a fitting projection is provided on a laser light absorbing surface at a contact end of the non-transparent resin material, and a contact end of the transparent resin material is provided. Is provided with a fitting concave portion which can be fitted with the fitting convex portion. The shape and size of the fitting protrusion and the fitting recess are not particularly limited, and may be, for example, a substantially trapezoidal shape, a substantially semicircular shape, a substantially triangular shape, or other cross-sectional shapes.

However, depending on the transparency of the resin used for the transparent resin material with respect to the laser light, the wavelength of the laser light used as the heating source, and the like, at least a part of the laser light reaching the fitting protrusion is 26%. It is preferable to set the shapes and sizes (transmission distances) of the fitting projections and the fitting recesses so that the laser light transmittance of not less than% can be secured.

As described above, the fitting projection is provided on the laser light absorbing surface at the contact end of the non-transparent resin material, and the fitting recess is provided at the contact end of the transparent resin material. The laser light transmission distance in the transparent resin material is reduced by the amount by which the non-transparent resin material has a convex shape (or the transparent resin material has a concave shape). For this reason, the energy loss of the laser beam during transmission through the transparent resin material is reduced. Therefore, more laser light can reach and be absorbed by the contact surface (absorption surface) of the non-transparent resin material, and the contact surfaces of the transparent resin material and the non-transparent resin material are sufficiently heated and melted. As a result, the bonding strength by laser welding can be improved.

By providing the fitting projection on the non-permeable resin material and the fitting recess on the transparent resin material, the fitting projection of the non-permeable resin material and the transparent resin material are provided. As a result, the mechanical coupling force is applied between the permeable resin material and the non-permeable resin material, so that the bonding strength between the two can be further improved.

In addition, the mechanical coupling force by the concave and convex fitting corrects the warp or the like at the contact end of the transparent resin material and the non-transparent resin material. The generation of a gap between the transparent resin material and the contact surface can be suppressed. For this reason, the heat generated on the contact surface of the non-transparent resin material is reliably transmitted to the contact surface of the transparent resin material, and the contact surface of the transparent resin material can be reliably heated and melted. Therefore, the contact surfaces of the transparent resin material and the non-transparent resin material can be reliably welded to each other by laser welding.

The type of resin used for the transparent resin material is not particularly limited as long as it has thermoplasticity and can transmit laser light as a heating source at a predetermined transmittance or higher. For example, nylon 6 (PA6) or nylon 66
(PA66), etc., polyamide (PA), polyethylene (PE), polypropylene (PP), styrene-acrylonitrile copolymer, polyethylene terephthalate (P
ET), polystyrene, ABS, acrylic (PMM
A), polycarbonate (PC), polybutylene terephthalate (PBT) and the like. If necessary, a reinforcing fiber such as glass fiber or carbon fiber or a coloring material may be used.

The type of resin used for the non-permeable resin material is not particularly limited as long as it has thermoplasticity and can absorb laser light as a heating source without transmitting it.
For example, nylon 6 (PA6) and nylon 66 (PA6
6) Polyamide (PA), polyethylene (PE), etc.
Polypropylene (PP), styrene-acrylonitrile copolymer, polyethylene terephthalate (PET), polystyrene, ABS, acrylic (PMMA), polycarbonate (PC), polybutylene terephthalate (PB)
T), PPS and the like, in which a predetermined coloring material such as carbon black, dye or pigment is mixed. In addition, what added reinforcing fiber, such as glass fiber and carbon fiber, may be used as needed.

The combination of the resin used for the permeable resin material and the resin used for the non-permeable resin material is as follows.
It is a combination of mutually compatible ones. 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, a combination of PET and PC, and a combination of PC and P
A combination with BT and the like can be given.

The type of laser light used as a heating source is determined by the transmittance in the transparent resin material in relation to the absorption spectrum and plate thickness (transmission length) of the transparent resin material that transmits the laser light. Having a wavelength such that is not less than a predetermined value is appropriately selected. For example, a YAG: Nd ³⁺ laser (wavelength of laser light: 1060 nm) or a semiconductor laser (wavelength of laser light: 500 to 1000 nm) can be used.

The 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.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) In this embodiment shown in FIGS. 1 to 3, the resin molded product of the present invention is applied to an intake manifold made of a synthetic resin. It is embodied.

FIG. 1 is a plan view of the intake manifold. FIG. 2 shows an intake manifold A in FIG.
A cut end face cut along the line A is shown in an enlarged manner.

The intake manifold 10 is divided into upper and lower parts, and the first molded member 1 is an upper divided body.
1 and a hollow body constituted by a second molded member 12 as a lower split body. First molded member 11 and second molded member 1
Reference numeral 2 has contact ends 11a and 12a, each of which is composed of a flange that abuts in alignment with each other. The contact surfaces 11b and 12b of the contact end 11a of the first molding member 11 and the contact end 12a of the second molding member 12 are integrally joined by laser welding.

The first molding member 11 is made of a transparent resin which is transparent to a laser beam as a heating source.
In this embodiment, a reinforced plastic obtained by adding 30 wt% of glass fiber as a reinforcing material to nylon 6 was used as the transparent resin. However, 3 pieces of glass fiber
By adding 0 wt%, the transmittance of laser light is reduced by 30% as compared with nylon 6 plastic without glass fiber. The laser beam used for irradiation is a YAG: Nd ³⁺ laser (wavelength: 1060 nm).

The second molding member 12 is made of a non-transparent resin that does not transmit laser light as a heating source. In this embodiment, the second molding member 12 is made of nylon 6 and a reinforcing material. A reinforced plastic obtained by adding an appropriate amount of 30 wt% of glass fiber and carbon black as an auxiliary agent (coloring material) was used.

The first molded member 11 and the second molded member 12 are both made of nylon 6 as a base resin.
They are compatible with each other.

The first molded member 11 has a substantially semi-cylindrical cross-sectional shape as shown in an enlarged view in FIG. 2 at a portion indicated by the line AA in FIG. This first semi-cylindrical first
An abutting end 11 a formed of a flange bulging in the centrifugal direction is provided at an opening end of the molding member 11.

Then, as shown in FIG. 3, this portion is further enlarged, and an annular concave portion 11c is provided on the upper surface of the contact end portion 11a. The concave portion 11c has a substantially trapezoidal cross-sectional shape in which the opening gradually expands from the bottom toward the upper side (the side irradiated with the laser beam). In addition, as described later, the upper surface of the contact end 11a serves as a laser light incident surface. The concave portion 11c is provided so that at least 26% (specifically, about 30%) of the laser light incident from the bottom surface of the laser light incident from the concave portion 11c can secure the laser light transmittance. The shape and size (transmission distance) are set.

On the other hand, similarly to the first molding member 11, the second molding member 12 has a substantially semi-cylindrical cross-sectional shape. A contact end portion 12a formed of a flange portion bulging in the direction is provided.

Then, the contact end 11 of the first molding member 11
a and the contact surface 11 of the contact end 12a of the second molding member 12
b and 12b are integrally joined by laser welding in a state where they are in contact with each other.

The resin molded product of the present example having the above configuration was manufactured as follows. First, the first molding member 11 and the second molding member 12 were injection molded in a predetermined shape using a predetermined injection molding die. And the first molding member 1
1 and the contact end 1 of the second molding member 12
The contact surfaces 11b and 12b of 2a were brought into contact with each other. In this state, a laser beam is irradiated from the first forming member 11 side using a laser torch (not shown). That is, by irradiating the laser light from the upper surface side of the contact end 11a of the first molding member 11 and causing the laser light to enter from the upper surface of the contact end 11a, the contact end 11a of the first molding member 11 is formed. Contact surfaces 11b and 12 between the second molding member 12 and the contact end 12a
b were heated and melted over the entire surface, and both were integrally joined by laser welding.

In the joint thus obtained, the contact surface 11
b and 12b are entirely melted and joined, and between the corresponding contact surfaces 11b and 12b, both resins constituting both molding members 11 and 12 are melted and entangled with each other to form a tangled state. Therefore, it forms a strong bonding state and has high bonding strength and pressure resistance.

In particular, in the resin molded product of this embodiment, since the concave portion 11c is provided on the laser beam incident surface at the contact end portion 11a of the first molded member 11 made of a transparent resin material, the concave shape is obtained. Accordingly, the transmission distance of the laser light in the transparent resin material becomes shorter.

That is, the laser beam incident on the bottom surface and the inclined side surface of the concave portion 11c with the incident surface
The contact surface 12b of the second molding member 12 made of a non-transparent resin material is smaller than the incident laser beam with the other surface (the upper surface of the contact end portion 11a where the concave portion 11c is not provided) as the incident surface. There is a tendency that the transmission distance through the first molding member 11 made of a transparent resin material before reaching the (absorbing surface) becomes shorter.

Thus, the energy loss of the laser beam during transmission through the first molding member 11 made of a transparent resin material is reduced. Therefore, more laser light can reach and be absorbed by the laser light absorbing surface of the contact end portion 12a of the second molding member 12 made of the non-transparent resin material, that is, the contact surface 12b of the contact end portion 12a. Yes, first
The contact surfaces 11b and 12b of the molding member 11 and the second molding member 12 can be sufficiently heated and melted to improve the bonding strength by laser welding.

The concave portion 11c has a substantially trapezoidal cross-sectional shape in which the opening gradually expands upward from the bottom surface (the side to which the laser beam is irradiated).
c as well as the laser light having the bottom surface of c as the incident surface.
Many laser beams having the inclined side surface 1c as the incident surface also have a short transmission distance. Therefore, it is advantageous to sufficiently heat and melt the contact surfaces 11b and 12b of the first molding member 11 and the second molding member 12 over a wider range.

Further, the recess 11c is
Since the shape and size are set such that at least the laser light incident from the bottom surface of the laser light incident from the bottom can secure a laser light transmittance of 26% or more,
Significantly improved welding strength can be obtained.

(Embodiment 2) The present embodiment shown in FIG. 4 embodies the resin molded product according to claim 1 or 2,
In the intake manifold of the first embodiment, the first
And the contact ends 11a and 1 of the second molded members 11 and 12
The shape of 2a is changed.

That is, the contact end 1 of the first molding member 11
1a, an annular recess 11c having a substantially trapezoidal cross-sectional shape as in the first embodiment is formed on the upper surface thereof (the incident surface of the laser beam).
Is provided, and an annular fitting projection 11d protruding downward is provided on the lower surface (contact surface 11b).
The fitting projection 11d has a substantially trapezoidal cross-sectional shape that gradually reduces and protrudes toward the distal end side (downward side).

On the other hand, the contact end 12a of the second molding member 12
Has an upper surface (a contact surface 12 serving as a laser light absorbing surface).
b) is provided with an annular fitting concave portion 12d capable of fitting with the fitting convex portion 11d. The fitting recess 12d has a shape that matches the fitting projection 11d, and has a substantially trapezoidal cross-sectional shape in which the opening gradually expands upward from the bottom surface (the side to which the laser beam is irradiated).

Here, the fitting projections 11d, the fitting recesses 12d, and the recesses 11c enter from the bottom surface and the inclined side surface of the fitting recess 11c, and enter the bottom surface and the inclined side surface of the fitting recess 12d. The shape and size (transmission distance) are set so that the reaching laser light can secure a laser light transmittance of 26% or more (specifically, about 30%).

The fitting projection 11 of the first molding member 11
d and the fitting recesses 12d of the second molding member 12 are fitted with each other, and the contact surface 11b (including the inclined side surface and the distal end surface of the fitting projection 11d) of the first molding member 11 and the second molding member The abutment surfaces 12b (including the inclined side surfaces and the bottom surface of the fitting recess 12d) are integrally joined by laser welding.

When manufacturing the resin molded product of the present embodiment having the above configuration, the fitting convex portion 11d of the first molding member 11 and the fitting concave portion 12d of the second molding member 12 are fitted together. In a state where the contact surfaces 11b and 12b of the first molding member 11 and the second molding member 12 are in contact with each other, laser light is emitted from the first molding member 11 side. That is, by irradiating the laser light from the upper surface side of the contact end 11a of the first molding member 11 and causing the laser light to enter from the upper surface of the contact end 11a, the contact end 11a of the first molding member 11 is formed. And the second
The contact surfaces 11b and 1 of the molding member 12 with the contact end 12a
2b are heated and melted over the entire surface, and both are integrally joined by laser welding.

Therefore, in the resin molded article of this embodiment,
In addition to the functions and effects of the resin molded product of the first embodiment,
The following operational effects are also achieved.

That is, in this resin molded product, a mechanical coupling force is applied between the fitting convex portion 11d of the first molding member 11 and the fitting concave portion 12d of the second molding member 12 by concave and convex fitting. As a result, the joint strength between the two can be further improved.

Further, the warping and the like at the contact end portions 11a and 12a of the first molding member 11 and the second molding member 12 are corrected by the mechanical coupling force due to the concave-convex fitting. The generation of a gap between the contact surfaces 11b and 12b of the second molding member 12 can be suppressed. For this reason, the heat generated at the contact surface 12b of the second molding member 12 made of the non-transparent resin material is reliably transferred to the contact surface 11b of the first molding member 11 made of the transparent resin material. The contact surface 11b of the member 11 can be reliably heated and melted. Therefore, the first molded member 11
In addition, the contact surfaces 11b and 12b of the second molding member 12 can be reliably laser-welded to each other.

Further, the contact surface 11b of the first molding member 11 (including the inclined side surface and the tip end surface of the fitting projection 11d) and the contact surface 1b of the second molding member 12 are formed by the concave and convex fitting.
Since the contact area with 2b (including the inclined side surface and the bottom surface of the fitting recess 12d), that is, the bonding area by laser welding is also increased, the bonding strength can also be improved.

In addition, the fitting protrusion 11d is provided on the first molding member 11 made of a transparent resin material, and the fitting recess 12d is formed on the second molding member 12 made of a non-permeable resin material.
Since d is provided, it is possible to utilize the fact that a part of the laser light is reflected on the inner surface (bottom surface and inclined side surface) of the fitting concave portion 12d, which is advantageous for more uniformly laser welding.

The fitting projection 11d and the fitting recess 1
The laser beam 2d and the concave portion 11c are incident from the bottom surface and the inclined side surface of the fitting concave portion 11c, and the laser light reaching the bottom surface and the inclined side surface of the fitting concave portion 12d secures a laser light transmittance of 26% or more. Since the shape and the size are set so as to be able to be obtained, the welding strength can be significantly improved.

(Embodiment 3) This embodiment shown in FIG. 5 is an embodiment of the resin molded product according to the third aspect. In the intake manifold of the first embodiment, the first and second molding members 11 are used. The shape of the contact end portions 11a and 12a of FIGS.

That is, the contact end 1 of the first molding member 11
An annular fitting recess 11e is provided on the lower surface (abutting surface 11b) of 1a. The fitting recess 11e has a substantially trapezoidal cross-sectional shape in which the opening gradually expands downward from the bottom surface.

On the other hand, the contact end 12a of the second molding member 12
Is provided on its upper surface (contact surface 12b serving as an absorption surface) with an annular fitting convex portion 12e capable of fitting with the fitting concave portion 11e. The fitting protrusion 12e is provided in the fitting recess 1
1e, and has a substantially trapezoidal cross-sectional shape that gradually shrinks and protrudes toward the distal end side (the side to which laser light is irradiated).

In the fitting concave portion 11e and the fitting convex portion 12e, at least 26% (specifically, 30% or more) of the laser light reaching the fitting convex portion 12e reaches the distal end surface. %), And the shape and size (transmission distance) thereof are set so that the laser beam transmittance of about (%) can be secured.

The fitting recess 11 of the first molding member 11
e and the fitting protrusions 12e of the second molding member 12 are fitted together, and the contact surface 11b (including the inclined side surface and the bottom surface of the fitting recess 11e) of the first molding member 11 and the second molding member 12 The contact surfaces 12b (including the inclined side surface and the distal end surface of the fitting projection 12e) are integrally joined by laser welding.

When manufacturing the resin molded product of the present embodiment having the above configuration, the fitting concave portion 11e of the first molding member 11 and the fitting convex portion 12e of the second molding member 12 are fitted together. In a state where the contact surfaces 11b and 12b of the first molding member 11 and the second molding member 12 are in contact with each other, laser light is emitted from the first molding member 11 side. That is, by irradiating the laser light from the upper surface side of the contact end 11a of the first molding member 11 and causing the laser light to enter from the upper surface of the contact end 11a, the contact end 11a of the first molding member 11 is formed. And the second
The contact surfaces 11b and 1 of the molding member 12 with the contact end 12a
2b are heated and melted over the entire surface, and both are integrally joined by laser welding.

Therefore, in the resin molded product of this embodiment,
Contact end 1 of second molded member 12 made of non-permeable resin material
A fitting projection 12e is provided on the laser light absorbing surface (contact surface 12b) in 2a, and a fitting recess 11e is formed on the contact end 11a of the first molding member 11 made of a transparent resin material.
Is provided, the transmission distance of the laser beam in the transparent resin material is shortened by the amount by which the non-transparent resin material has a convex shape (or the transparent resin material has a concave shape).

That is, the laser beam reaching the tip end surface and the inclined side surface of the fitting projection 12e is applied to the other surface of the second molding member 12 (the contact end 12a of the portion where the fitting projection 12e is not provided). (The upper surface of the first member) tends to be shorter than the laser beam reaching the first molding member 11 made of a transparent resin material.

Therefore, the energy loss of the laser beam during transmission through the first molding member 11 made of a transparent resin material is reduced. Therefore, more laser light can reach and be absorbed by the contact surface (absorption surface) 12b of the second molding member 12 made of a non-transparent resin material, and the contact between the first molding member 11 and the second molding member 12 can be achieved. Contact surfaces 11b and 12b
It is possible to sufficiently heat and fuse them to improve the bonding strength by laser welding.

If the fitting concave portion 11e is provided on the first molding member 11 and the fitting convex portion 12e is provided on the second molding member 12 as described above, the first molding member 11 and Since a mechanical coupling force is applied between the second molding member 12 and the second molding member 12, the joining strength between the two can be further improved.

Further, the mechanical coupling force due to the concave-convex fitting corrects the warp or the like at the contact end portions 11a and 12a of the first molding member 11 and the second molding member 12, so that it is made of a transparent resin material. The contact surface 11b of the first molding member 11 and the contact surface 12 of the second molding member 12 made of a non-permeable resin material
b can be suppressed from occurring.
For this reason, the heat generated at the contact surface 12b of the second molding member 12 made of the non-transparent resin material is reduced by the first material made of the transparent resin material.
The heat is reliably transferred to the contact surface 11b of the molded member 11, so that the contact surface 11b of the first molded member 11 can be reliably heated and melted. Therefore, the contact surfaces 11b and 12b of the first molding member and the second molding member 12 can be reliably welded by laser.

Further, since the fitting convex portion 12e has a substantially trapezoidal cross-sectional shape that gradually shrinks and protrudes toward the distal end side (the side irradiated with the laser beam), In comparison with a case where the cross-sectional shape gradually expands and protrudes toward the light irradiation side), the fitting protrusion 1
This is advantageous for irradiating and absorbing the laser beam on the inclined side surface 2e or the like.

In addition, the fitting concave portion 11e and the fitting convex portion 12e have a laser light transmittance of 26% or more of the laser light reaching the fitting convex portion 12e. Since the shape and size are set so as to be able to be secured, it is possible to achieve a significantly improved welding strength.

(Relationship between Laser Beam Transmittance and Welding Strength) Nylon 6 reinforced by adding 30 wt% of glass fiber
And a non-transparent resin material having a thickness of 3 mm made of nylon 6 to which a predetermined amount of carbon black has been added, and transmitting a YAG: Nd ³⁺ laser (wavelength: 1060 nm). Irradiation was performed from the conductive resin material side, and they were integrally joined by laser welding. The output of the laser was 400 W and the processing speed was 4 m / min.

Then, a dye as a colorant is added to the transparent resin material, and the amount of the dye is variously changed, so that the laser light transmittance of the transparent resin material is variously changed, and the laser light transmittance of the transparent resin material is changed. The relationship between light transmittance and welding strength was examined. FIG. 6 shows the result.

As is clear from FIG. 6, when the laser beam transmittance of the transparent resin material is 26% or more, the welding strength becomes 45 MPa or more, and a sufficient welding strength can be achieved.

The laser beam transmittance was measured by calculating the incident energy depending on the presence or absence of a work, and the welding strength was measured by pulling and breaking the welded portion.

[0077]

As described above in detail, according to the resin molded product of the present invention, the transmission distance of the laser light transmitted through the transparent resin material during laser welding is shortened. More laser light can reach and be absorbed by the contact surface, which is advantageous for improving the bonding strength by laser welding.

Further, when the transmission distance of the laser beam in the transmission resin material is reduced, the energy of the laser beam can be more efficiently used for laser welding, and the energy consumption can be reduced, thereby contributing to cost reduction. .

[Brief description of the drawings]

FIG. 1 is a plan view of a synthetic resin intake manifold to which a resin molded product according to the present invention is applied according to a first embodiment.

FIG. 2 is a cross-sectional view of a portion indicated by an arrow AA line in FIG. 1 according to the first embodiment.

FIG. 3 is an enlarged partial cross-sectional view showing a joint structure between a first molding member and a second molding member according to the first embodiment.

FIG. 4 is an enlarged partial cross-sectional view showing a joint structure between a first molding member and a second molding member according to the second embodiment.

FIG. 5 is an enlarged partial cross-sectional view showing a joint structure between a first molding member and a second molding member according to the third embodiment.

FIG. 6 is a diagram showing a relationship between laser light transmittance and welding strength in a transparent resin material.

[Explanation of symbols]

 11: First molded member (permeable resin material) 12: Second molded member (non-permeable resin material) 11a, 12a: Contact end portion 11b, 12b: Contact surface 11c: Depression 11d, 12e: Fitting convex Part 11e, 12d ... fitting recess

Claims (3)

[Claims] 1. A light-transmitting resin material having a transparency to a laser beam as a heating source, and a non-transparent resin material having no transparency to the laser beam. In the resin molded product in which the contact ends of the transparent resin material are welded and joined by the irradiation of the laser beam from the transparent resin material side, the laser at the contact end of the transparent resin material is A resin molded product, wherein a concave portion is provided on a light incident surface. 2. A fitting recess is provided on the laser light absorbing surface at the contact end of the non-transparent resin material, and the fitting recess is provided at the contact end of the transparent resin material. The resin molded product according to claim 1, further comprising a fitting protrusion that can be fitted. 3. A transparent resin material that is permeable to laser light as a heating source, and a non-transparent resin material that is not permeable to the laser light. In a resin molded product in which abutting end portions of a transparent resin material are welded and joined by irradiation of the laser light from the transparent resin material side, A fitting projection is provided on the laser light absorbing surface, and a fitting recess is provided at the abutting end of the transparent resin material, the fitting recess being engageable with the fitting projection. Resin molded products.