JP7694243B2 - Resin structure and method for producing resin structure - Google Patents

Description

The present invention relates to a resin structure and a method for producing a resin structure.

Patent Document 1 discloses a laser welding method for laser welding a transparent resin member made of an amorphous resin and an absorbent resin member made of a crystalline resin. The laser welding method described in Patent Document 1 irradiates the surface of the absorbent resin member with laser light through the transparent resin member. As a result, the surface of the absorbent resin member absorbs the laser light and generates heat, and this heat welds the absorbent resin member and the translucent resin member.

JP 2003-225946 A

Here, the higher the crystallinity of a resin member, the higher the heat of crystalline fusion tends to be, so when attempting to weld a highly crystalline resin member, such as a crystalline resin, high heat must be generated. Therefore, when welding a highly crystalline resin member, there is a risk that the resin member may exceed its thermal decomposition temperature and deteriorate, or voids may be generated, resulting in a decrease in weld strength. On the other hand, if a resin member with low crystallinity is simply used as the resin member to be welded, there is a risk that the rigidity of the resin itself may not be ensured.

The present invention has been made in consideration of the above circumstances, and aims to provide a resin structure and a method for manufacturing a resin structure that can improve welding strength while suppressing a decrease in overall rigidity.

To achieve the above object, the present invention provides a resin structure comprising a first resin member and a second resin member welded to each other, in which at least one of the first resin member and the second resin member has a main body portion and a low crystallinity layer formed on a surface portion and having a lower crystallinity than the main body portion, and the first resin member and the second resin member are welded to each other at the low crystallinity layer of at least one of the first resin member and the second resin member.

In order to achieve the above object, the present invention provides a method for manufacturing a resin structure by welding a first resin member and a second resin member, the method comprising the steps of: forming a low crystallinity layer having a lower crystallinity than a main body portion at a portion of the surface portion of at least one of the first resin member and the second resin member that will be the welding portion; and welding the first resin member and the second resin member at the low crystallinity layer of at least one of the first resin member and the second resin member.

The present invention makes it possible to provide a resin structure and a method for manufacturing a resin structure that can improve welding strength while suppressing a decrease in overall rigidity.

1 is a cross-sectional view of a rotation speed sensor according to a first embodiment. 1 is an exploded cross-sectional view of a rotation speed sensor according to a first embodiment. 4 is a photograph taken by an optical microscope of a cross section of a first resin member in the first embodiment. FIG. 11 is a perspective view showing a step of welding a first resin member and a second resin member in the first embodiment. 4 is an enlarged cross-sectional view of the first embodiment, showing the vicinity of a mating surface between a first resin member and a second resin member before welding. FIG. 4 is an enlarged cross-sectional view of the vicinity of a mating surface between a first resin member and a second resin member during welding in the first embodiment; FIG. 7 is an enlarged cross-sectional view showing a state next to that of FIG. 6 in the first embodiment, in which the vicinity of a mating surface between a first resin member and a second resin member is enlarged. FIG. 8 is an enlarged cross-sectional view showing a state next to that of FIG. 7 in the first embodiment, in which the vicinity of a mating surface between a first resin member and a second resin member is enlarged. FIG. FIG. 11 is an enlarged cross-sectional view of a portion of a rotation speed sensor according to a second embodiment.

[First embodiment]
A first embodiment of the present invention will be described with reference to Figures 1 to 8. Note that the embodiment described below is shown as a preferred specific example for carrying out the present invention, and while there are some parts that specifically exemplify various technical matters that are technically preferable, the technical scope of the present invention is not limited to this specific embodiment.

(Rotational speed sensor 1)
In this embodiment, an example is shown in which a resin structure 2 is applied to a rotation speed sensor 1. Fig. 1 is a cross-sectional view of the rotation speed sensor 1 of this embodiment. Fig. 2 is an exploded cross-sectional view of the rotation speed sensor 1 of this embodiment.

The rotational speed sensor 1 is a sensor for detecting the rotational speed of a rotating body mounted on, for example, an automobile. For example, the rotational speed sensor 1 can be an ABS sensor that detects the rotational speed of the wheels of an automobile and is used in an ABS (antilock braking system). The rotational speed sensor 1 may also be a rotational speed sensor that detects the rotational speed of a rotating body other than the wheels mounted on an automobile, such as a compressor wheel of a turbocharger. The resin structure 2 can be applied to devices other than the rotational speed sensor 1. As an example, the resin structure 2 can be used as a housing and cover that accommodate various electronic components. The resin structure 2 does not have to constitute a housing and cover.

The rotation speed sensor 1 includes a first resin member 21 and a second resin member 22 welded together, a sensor IC 3 as an electronic component housed within the first resin member 21 and the second resin member 22, and a cable 4 connected to the sensor IC 3.

The first resin member 21 is a housing that houses the sensor IC 3, and the second resin member 22 is a cover that closes the opening of the first resin member 21. Each of the first resin member 21 and the second resin member 22 is made of a thermoplastic resin having electrical insulation properties. For example, each of the first resin member 21 and the second resin member 22 can be made of engineering plastics such as polyamide (PA) and polybutylene terephthalate (PBT), and super engineering plastics such as polyphenylene sulfide (PPS). In addition, the engineering plastic and the super engineering plastic may contain glass fiber or the like as a reinforcing material. In this embodiment, the first resin member 21 and the second resin member 22 are made of the same type of resin material. In addition, a combination of different types of resin materials that can be welded to each other can be used as the resin materials constituting the first resin member 21 and the second resin member 22.

The first resin member 21 has a housing portion 211 that opens on one side and houses the sensor IC 3, and an attachment portion 212 that protrudes from the housing portion 211 to the outer periphery. The housing portion 211 is cup-shaped and opens toward the second resin member 22. The attachment portion 212 has a bolt insertion hole 212a formed therein, and is fixed to the vehicle body or the like using a bolt.

The second resin member 22 is provided on the outer periphery of the cable 4. The second resin member 22 is molded integrally with the cable 4 by insert molding, in which the cable 4 is inserted into a mold for molding the second resin member 22. The second resin member 22 has a generally cylindrical shape, and has a large diameter portion 221 at the end on the first resin member 21 side, the entire circumference of which protrudes toward the outer periphery. The large diameter portion 221 abuts against the surface of the first resin member 21 on the second resin member 22 side, and closes the storage portion 211. The large diameter portion 221 is welded around the entire circumference around the opening of the storage portion 211 in the first resin member 21.

The first resin member 21 and the second resin member 22 each include a main body portion 213, 222 and a low crystallinity layer 214, 223 that has lower crystallinity than the main body portion 213, 222. The low crystallinity layers 214, 223 are formed on the surface portion of the first resin member 21 and the second resin member 22, respectively. The "surface portion" here refers to a portion of the first resin member 21 or the second resin member 22 that constitutes the surface of the first resin member 21 or the second resin member 22 and has a predetermined thickness, and is a portion that comes into contact with a mold when the first resin member 21 or the second resin member 22 is molded.

In this embodiment, the main body 213, 222 is a crystalline resin. The low crystallinity layer 214, 223 is not amorphous and does not have a crystal structure, but is made of a low crystallinity resin that is less crystalline than the main body 213, 222. The crystallinity of each of the main body 213, 222 and the low crystallinity layer 214, 223 can be evaluated, for example, by the degree of crystallization. The crystallinity can also be evaluated, for example, by the heat of crystalline fusion. That is, the higher the heat of crystalline fusion, the higher the crystallinity can be evaluated. A method for forming the main body 213, 222 and the low crystallinity layer 214, 223 in each of the first resin member 21 and the second resin member 22 will be described later. Note that in FIG. 1 and FIG. 2, the thickness of the low crystallinity layer 214, 223 is exaggerated for convenience. For convenience, the thickness of the low crystallinity layers 214 and 223 is shown to be uniform throughout in Figures 1 and 2, but it does not have to be uniform.

In this embodiment, the first resin member 21 and the second resin member 22 are fixed to each other by laser welding. The first resin member 21 is an absorbent material to which a colorant is added to impart laser absorption. As the colorant, for example, a carbon-based material such as carbon black can be used. The second resin member 22 is a transparent material configured to have laser transparency. The second resin member 22 does not need to be visually transparent, but only needs to transmit the laser light used during laser welding. As will be described in detail later, the welded portion 10 between the first resin member 21 and the second resin member 22 is formed in the low crystallinity layers 214 and 223 of the first resin member 21 and the second resin member 22. The sensor IC 3 is housed in the area surrounded by the first resin member 21 and the second resin member 22.

The sensor IC3 is equipped with magnetic detection elements such as a GMR (Giant Magneto Resistive effect) element, an AMR (Anisotropic Magneto Resistive) element, a TMR (Tunneling Magneto Resistive) element, a Hall element, etc. The detection signal of the sensor IC3 is output to a control device or the like arranged in the vehicle through the cable 4.

The cable 4 includes a pair of electric wires 41 connected to the sensor IC 3, and a sheath 42 that covers the pair of electric wires 41 together. The pair of electric wires 41 are connected to a pair of terminals 31 of the sensor IC 3. The sheath 42 is made of an insulating resin or the like. The sheath 42 and the second resin member 22 are integrated by the above-mentioned insert molding of the second resin member 22.

(Method of Manufacturing Rotational Speed Sensor 1)
Next, a method for manufacturing the rotation speed sensor 1 will be described.
The manufacturing method of the rotation speed sensor 1 includes a step of manufacturing a first resin member 21, a step of manufacturing a second resin member 22 so as to be integrated with the cable 4, and a step of welding the first resin member 21 and the second resin member 22 together.

In the process of manufacturing the first resin member 21, the high-temperature molten resin constituting the first resin member 21 is injected into a mold for molding the first resin member 21, and the molten resin is cooled to mold the first resin member 21. Here, when manufacturing the first resin member 21, a design is made so that the portion of the first resin member 21 that is welded to the second resin member 22 becomes a low-crystallinity layer 214. As an example of such a design, a water hole for flowing low-temperature cooling water below a predetermined temperature may be provided in the mold near the portion of the first resin member 21 that is welded to the second resin member 22. When the low-crystallinity layer 214 is formed on almost the entire surface of the first resin member 21 as in this embodiment, the position of the water hole of the mold and the temperature of the cooling water are designed so that the temperature of the entire surface constituting the cavity in the mold is a low temperature below a predetermined temperature. As a result, a low-crystallinity layer 214 with low crystallinity is formed in the portion of the molten resin that contacts the mold, i.e., the portion that becomes the surface portion of the first resin member 21. The molten resin located away from the mold is cooled at a relatively slow rate, forming the main body portion 213, which has higher crystallinity than the low crystallinity layer 214.

In addition, even in the conventional method, the mold has water holes to harden the molten resin in the mold. However, in order to form the low crystallinity layer 214 on the surface of the first resin member 21, it is necessary to design the position of the water holes in the mold and the temperature of the cooling water so that the surface of the molten resin is cooled at a cooling rate equal to or higher than a predetermined rate. That is, in this embodiment, the manufacturing method of the first resin member 21 is devised compared to the conventional method so that the low crystallinity layer 214 is intentionally formed at a desired position of the first resin member 21. The cooling rate required to form the low crystallinity layer 214 varies depending on the resin material constituting the first resin member 21. The faster the cooling rate of the molten resin in the mold near the mold, the thicker the low crystallinity layer 214 tends to be.

In the process of manufacturing the second resin member 22, the cable 4 is inserted into a mold for the second resin member 22, and the high-temperature molten resin that constitutes the second resin member 22 is injected into the mold and cooled to form the second resin member 22. When manufacturing the second resin member 22, the part of the second resin member 22 that is welded to the first resin member 21 is designed to become the low crystallinity layer 223. This design is similar to the design for forming the low crystallinity layer 214 in the first resin member 21, and in the second resin member 22, the low crystallinity layer 223 is formed on the surface portion, and the main body portion 222 is formed outside the surface portion. Note that, in the part of the surface portion of the second resin member 22 that touches the cable 4 and does not touch the mold during molding, the low crystallinity layer 223 is not formed, and the main body portion 222 has high crystallinity.

Figure 3 is a photograph of the cross section of the first resin member 21 taken with an optical microscope. The first resin member 21 shown in Figure 3 is a PA resin containing glass fibers. A scale of 500 μm is shown in the lower right of Figure 3. When the cross section is viewed with an optical microscope, the layer structures of the main body 213 and the low crystallinity layer 214 appear different. That is, by observing the cross section of the first resin member 21 with an optical microscope or the like, it is possible to determine whether the main body 213 and the low crystallinity layer 214 are formed in the first resin member 21. The same is true for the main body 222 and the low crystallinity layer 223 in the second resin member 22. In Figure 3, the surface of the first resin member 21 is represented by the symbol 210 to make the surface position of the first resin member 21 easier to understand. In addition, in Figure 3, the pedestal on which the first resin member 21 was placed when the cross section of the first resin member 21 was photographed is shown above the surface 210.

4 is a perspective view showing a process of welding the first resin member 21 and the second resin member 22. In this embodiment, a laser beam 51 is applied to the surface of the first resin member 21 through the second resin member 22 to laser-weld the first resin member 21 and the second resin member 22. At this time, the first resin member 21 and the second resin member 22 are laser-welded over the entire circumference of the cable 4 by making a laser device 5 emitting the laser beam 51 go around the cable 4 once or multiple times. As the laser device 5, a gas laser such as a _CO2 laser, or a solid laser such as a YAG laser or a Yb fiber laser can be used. In FIG. 4, the location where the laser beam 51 is to be applied is indicated by a two-dot chain line.

Figures 5 to 8 are schematic diagrams sequentially showing how the welded portion 10 is formed during the laser welding process. For convenience, in Figures 5 to 8, the boundary between the main body portion 213 of the first resin member 21 and the low crystallinity layer 214, and the boundary between the main body portion 222 of the second resin member 22 and the low crystallinity layer 223 are each represented by a dashed line. Figures 6 and 7 show the state during irradiation with laser light 51, with the irradiation range of laser light 51 indicated by a two-dot chain line and the irradiation direction of laser light 51 indicated by a hollow arrow.

As shown in Fig. 6, when the surface of the first resin member 21 is irradiated with laser light 51 through the second resin member 22, first, the low crystallinity layer 214 of the first resin member 21 absorbs the laser light 51 and generates heat, forming a molten portion 100 in the low crystallinity layer 214. Then, as shown by the thin arrow emanating from the molten portion 100 of the first resin member 21 in Fig. 6, the heat generated by absorbing the laser light 51 in the first resin member 21 is transferred from the first resin member 21 to the second resin member 22. Due to this heat transfer, the low crystallinity layer 223 of the second resin member 22 melts together with the low crystallinity layer 214 of the first resin member 21, and the molten portion 100 spreads, as shown in Fig. 7. Then, as shown in FIG. 8, by ending the irradiation of the laser light 51, the heat generation stops and the molten portion 100 between the low crystallinity layer 214 of the first resin member 21 and the low crystallinity layer 223 of the second resin member 22 hardens, forming the welded portion 10. In this way, the first resin member 21 and the second resin member 22 are welded to each other at the low crystallinity layers 214, 223.

The welded portion 10 is preferably formed so as to fit within the formation range of the low crystallinity layer 214 of the first resin member 21 and the low crystallinity layer 223 of the second resin member 22, and is not formed in the main body portion 213 of the first resin member 21 or the main body portion 222 of the second resin member 22. Note that a part of the welded portion 10 may be formed so as to protrude into at least one of the main body portion 213 of the first resin member 21 and the main body portion 222 of the second resin member 22. In this case, it is preferable that more than half (more preferably more than 80%) of the volume of the welded portion 10 is contained within the formation area of the low crystallinity layer 214 of the first resin member 21 and the low crystallinity layer 223 of the second resin member 22.

It is preferable that the thickness of the portion where the welded portion 10 is formed in the low crystallinity layer 223 of the second resin member 22 is greater than the thickness of the portion where the welded portion 10 is formed in the low crystallinity layer 214 of the first resin member 21. As described above, the low crystallinity layer 223 of the second resin member 22 is melted by indirectly receiving the heat of the laser light 51 by the heat generated on the first resin member 21 side being transmitted, so that it is less likely to melt than the low crystallinity layer 214 of the first resin member 21 during laser welding. Therefore, by forming the thickness of the portion where the welded portion 10 is formed in the low crystallinity layer 223 of the second resin member 22 thick, it becomes easier to melt the low crystallinity layer 223 of the second resin member 22 during laser welding. Note that this is not limited to this, and for example, the thickness of the portion where the welded portion 10 is formed in the low crystallinity layer 214 of the first resin member 21 may be equal to the thickness of the portion where the welded portion 10 is formed in the low crystallinity layer 223 of the second resin member 22. In addition, the thickness of the portion of the low crystallinity layer 214 of the first resin member 21 where the welded portion 10 is formed may be greater than the thickness of the portion of the low crystallinity layer 223 of the second resin member 22 where the welded portion 10 is formed.

(Functions and Effects of the First Embodiment)
In this embodiment, each of the first resin member 21 and the second resin member 22 has a main body portion 213, 222 and a low crystallinity layer 214, 223 formed on the surface portion and having a lower crystallinity than the main body portion 213, 222. The first resin member 21 and the second resin member 22 are welded to each other at the low crystallinity layers 214, 223. In this manner, the first resin member 21 and the second resin member 22 are welded to each other at the low crystallinity layers 214, 223 that melt at a relatively low temperature, thereby reducing the heat required for welding. Therefore, it is possible to suppress the first resin member 21 and the second resin member 22 from exceeding the thermal decomposition temperature during welding, causing the first resin member 21 and the second resin member 22 to deteriorate or voids to occur in the welded portion 10. This can improve the welding strength between the first resin member 21 and the second resin member 22. In addition, the heat required for welding is reduced, so that the energy required for welding (for example, the irradiation energy of laser light when welding is laser welding) can be reduced. Furthermore, by forming the main body parts 213, 222 having higher crystallinity than the low crystallinity layers 214, 223 in the first resin member 21 and the second resin member 22, it is possible to suppress a decrease in the rigidity of the entire resin structure 2 having the first resin member 21 and the second resin member 22. The above-mentioned effect is an effect that can be obtained if a main body part and a low crystallinity layer are formed in at least one of the first resin member 21 and the second resin member 22, and the first resin member and the second resin member are welded in the low crystallinity layer. And, the above-mentioned effect is an effect that can be obtained more significantly when the main body parts 213, 222 and the low crystallinity layers 214, 223 are formed in the first resin member 21 and the second resin member 22, respectively, as in this embodiment, and the first resin member 21 and the second resin member 22 are welded to each other at the low crystallinity layers 214, 223.

The first resin member 21 is made of an absorbent material that absorbs the laser light 51, and the second resin member 22 is made of a transparent material that transmits the laser light 51. The first resin member 21 and the second resin member 22 are laser welded to each other by the laser light 51. This makes it possible to prevent the heat generated during welding from spreading over a wide area.

The first resin member 21 made of an absorbent material and the second resin member 22 made of a transparent material are made of the same type of resin material. That is, the melting points of the first resin member 21 and the second resin member 22 are the same. Here, as described above, during laser welding, the first resin member 21 is irradiated with laser light and generates heat, causing the first resin member 21 to melt, and this heat is transferred to the second resin member 22, causing the second resin member 22 to melt. Because of this mechanism, in order to melt both the first resin member 21 and the second resin member 22, which are made of the same resin material, it is necessary to make the heat generated in the first resin member 21 somewhat higher than the melting points of the first resin member 21 and the second resin member 22. Therefore, unless special measures are taken, the first resin member 21 may exceed its thermal decomposition temperature, deteriorate, or voids may occur in the molten part. Therefore, as in this embodiment, the first resin member 21 and the second resin member 22, which are made of the same type of resin material, are laser-welded to each other at the low crystallinity layers 214, 223, so that the heat required for welding can be reduced. As a result, deterioration of the first resin member 21 and the generation of voids in the welded portion 10 can be suppressed, and the welding strength between the first resin member 21 and the second resin member 22 can be improved.

The resin structure 2, which is made up of the first resin member 21 and the second resin member 22, is used to house an electronic component (sensor IC 3 in this embodiment). As described above, this embodiment can reduce the heat generated during welding, so that the electronic component housed in the resin structure 2 can be prevented from being affected by the heat during welding.

As described above, this embodiment can provide a resin structure and a method for manufacturing a resin structure that can improve the weld strength while suppressing a decrease in the overall rigidity.

[Second embodiment]
FIG. 9 is an enlarged cross-sectional view of a portion of the rotation speed sensor 1 in this embodiment.

This embodiment is an embodiment in which the location where the low crystallinity layer 214 is formed in the first resin member 21 and the location where the low crystallinity layer 223 is formed in the second resin member 22 are changed from the first embodiment. In this embodiment, the low crystallinity layers 214, 223 are formed only in the vicinity of the welded portion 10 between the first resin member 21 and the second resin member 22.

When manufacturing the first resin member 21 and the second resin member 22 of this embodiment, for example, the low crystallinity layers 214, 223 can be formed at the desired positions by devising a mold for forming the first resin member 21 and a mold for forming the second resin member 22. For example, the low crystallinity layers 214, 223 can be formed at the desired positions by forming water holes in the mold only near the areas in the mold where the low crystallinity layers 214, 223 are formed.

The other configurations of this embodiment are similar to those of the first embodiment.
In addition, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previously described embodiments represent the same components, etc. as those in the previously described embodiments, unless otherwise specified.

(Functions and Effects of the Second Embodiment)
In this embodiment, other than the welded portions 10 of the first resin member 21 and the second resin member 22, the first resin member 21 and the second resin member 22 are composed of main body portions 213, 222 which have relatively high crystallinity, so that the rigidity of the resin structure 2 having the first resin member 21 and the second resin member 22 can be increased.
In addition, this embodiment also has the same operational effects as the first embodiment.

(Summary of the embodiment)
Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[1] A resin structure (2) comprising a first resin member (21) and a second resin member (22) welded to each other, wherein at least one of the first resin member (21) and the second resin member (22) has a main body portion (213, 222) and a low crystallinity layer (214, 223) formed on a surface portion and having a lower crystallinity than the main body portion (213, 222), and the first resin member (21) and the second resin member (22) are welded to each other at the low crystallinity layer (214, 223) of at least one of the first resin member (21) and the second resin member (22).

[2] The resin structure (2) described in [1], in which the first resin member (21) is made of an absorbent material that absorbs the laser light (51), the second resin member (22) is made of a transparent material that transmits the laser light (51), and the first resin member (21) and the second resin member (22) are laser welded to each other by the laser light.

[3] The resin structure (2) described in [2], in which at least the second resin member (22) of the first resin member (21) and the second resin member (22) has the main body portion (222) and the low crystallinity layer (223), and the first resin member (21) and the low crystallinity layer (223) of the second resin member (22) are laser welded to each other by the laser light (51).

[4] The resin structure (2) described in [3], in which the first resin member (21) and the second resin member (22) are made of the same type of resin material.

[5] The first resin member (21) and the second resin member (22) each have the main body portion (213, 222) and the low crystallinity layer (214, 223), and the first resin member (21) and the second resin member (22) are welded to each other at the low crystallinity layers (214, 223). Any one of the resin structures (2) in [1] to [4].

[6] A resin structure (2) according to any one of [1] to [5], used to house an electronic component (3).

[7] A method for producing a resin structure (2) formed by welding a first resin member (21) and a second resin member (22), comprising the steps of: forming a low crystallinity layer (214, 223) having a lower crystallinity than a main body portion (213, 222) at a portion of the surface of at least one of the first resin member (21) and the second resin member (22) that will be the welding portion; and welding the first resin member (21) and the second resin member (22) at the low crystallinity layer (214, 223) of at least one of the first resin member (21) and the second resin member (22).

[8] The method for producing a resin structure (2) described in [7], in which the first resin member (21) is made of an absorbent material that absorbs the laser light (51), the second resin member (22) is made of a transparent material that transmits the laser light (51), and in the step of welding the first resin member (21) and the second resin member (22), the first resin member (21) and the second resin member (22) are laser-welded to each other by the laser light (51).

[9] The method for producing a resin structure (2) described in [8], wherein at least the second resin member (22) of the first resin member (21) and the second resin member (22) has the main body portion (222) and the low crystallinity layer (223), and in the process of welding the first resin member (21) and the second resin member (22), the first resin member (21) and the low crystallinity layer (223) of the second resin member (22) are laser-welded to each other by the laser light (51).

(Additional Note)
Although the embodiment of the present invention has been described above, the invention according to the claims is not limited to the above embodiment. It should be noted that not all of the combinations of features described in the embodiment are essential to the means for solving the problems of the invention. The present invention can be modified appropriately without departing from the spirit of the invention.

For example, in each of the above-described embodiments, an example in which the low crystallinity layer is formed on both the first resin member and the second resin member has been shown, but this is not limited thereto, and the low crystallinity layer may be formed on only one of the first resin member and the second resin member. In this case, as in each of the above-described embodiments, when the first resin member is composed of an absorbent material and the second resin member is composed of a transparent material and these are laser welded, it is preferable to form a low crystallinity layer on the second resin member. As described above, the second resin member melts by receiving heat generated in the first resin member, so the second resin member is less likely to become hotter than the first resin member, and by forming a low crystallinity layer on the second resin member, the second resin member is more likely to melt during welding.

In addition, in each of the above-described embodiments, an example has been shown in which the first resin member and the second resin member are fixed by laser welding, but it is also possible to adopt a welding method other than laser welding. For example, the first resin member and the second resin member can be fixed by vibration welding, ultrasonic welding, high frequency welding, heat welding, etc. Even in these cases, by performing welding in the low crystallinity layer of at least one of the first resin member and the second resin member, it is possible to reduce the heat required during welding and the energy (for example, the energy required to generate vibration in the case of vibration welding or ultrasonic welding).

2... Resin structure 21... First resin member 213... Main body portion 214... Low crystallinity layer 22... Second resin member 222... Main body portion 223... Low crystallinity layer 3... Sensor IC

Claims (6)

A resin structure including a first resin member and a second resin member welded to each other,
the first resin member made of an absorbent material that absorbs laser light has a first main body portion and a first low crystallinity layer formed on a surface portion and having a lower crystallinity than the first main body portion;
the second resin member made of a transparent material that transmits the laser light has a second main body portion and a second low-crystallinity layer formed on a surface portion and having a lower crystallinity than the second main body portion;
the first low crystallinity layer and the second low crystallinity layer are laser welded to each other by the laser light ;
The thickness of the second low-crystallinity layer is greater than the thickness of the first low-crystallinity layer.
Resin structure. The first resin member and the second resin member are made of the same type of resin material.
The resin structure according to claim 1 . The resin material is a PA resin containing glass fibers.
The resin structure according to claim 2 . Used to house electronic components,
The resin structure according to any one of claims 1 to 3 . A method for producing a resin structure formed by welding a first resin member and a second resin member, comprising the steps of:
a first step of forming a first low-crystallinity layer having a lower crystallinity than a first main body portion in a first portion of a surface portion of the first resin member made of an absorbent material that absorbs laser light , the first low-crystallinity layer having a lower crystallinity than a first main body portion, the first low-crystallinity layer being located at a first portion of a surface portion of the first resin member that is to be welded;
a second step of forming a second low-crystallinity layer having a lower crystallinity than the second body portion in a second portion of the surface portion of the second resin member made of a transparent material that transmits the laser light, the second low-crystallinity layer having a lower crystallinity than the second body portion, the second low-crystallinity layer being a welding location in the surface portion;
a third step of laser welding the first low crystallinity layer and the second low crystallinity layer to each other by the laser light ,
The second low-crystallinity layer is formed to have a thickness greater than a thickness of the first low-crystallinity layer.
A method for producing a resin structure. the first step is performed by preparing a first mold having a water hole for flowing cooling water in the vicinity of the first portion so that the first portion becomes the first low crystallinity layer, injecting a molten resin constituting the first resin member into the first mold, and cooling the molten resin;
The second step is performed by preparing a second mold having a water hole for flowing cooling water in the vicinity of the second portion so that the second portion becomes the second low crystallinity layer, and injecting a molten resin constituting the second resin member into the second mold and cooling the molten resin.
A method for producing the resin structure according to claim 5 .

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