JP2022153837A - Conjugate - Google Patents

Abstract

To provide a conjugate formed by laminating and integrating at least three components, in which restrictions in arrangement of a protrusion such as a welding rib are less likely to occur.SOLUTION: A conjugate (1) includes at least a first component (10), a second component (20), and a third component (30) laminated and integrally formed, wherein: the first component (10) and the second component (20) are conjugated to each other with at least one of a first oscillation welding part (6) formed by oscillation welding; the second component (20) and the third component (30) are conjugated to each other with at least one of a second oscillation welding part (7) formed by oscillation welding; and at least a part of the first oscillation welding part (6) and at least a part of the second oscillation welding part (7) are arranged in a site overlapping in a lamination direction.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a joined body in which at least a first member, a second member, and a third member each made of synthetic resin are laminated and integrally formed.

2. Description of the Related Art Conventionally, it is known to join two or more members (for example, resin moldings) made of synthetic resin by vibration welding. In vibration welding, the two members to be welded are brought into contact with each other, and by further vibrating them while applying pressure, the contacting portions (contact surfaces) of the two members can be melted and joined. For example, Japanese Patent Application Laid-Open No. 2009-262814 (Patent Document 1) discloses a mounting structure for a vehicle molded product that is mounted on an instrument panel of a vehicle by stacking synthetic resin molded products and vibration welding them. .

JP 2009-262814 A

As for the conventional vibration welding, referring to FIGS. 4 and 5, a second synthetic resin member 72 and a third synthetic resin member 73 are attached to a first synthetic resin member 71 twice. A case in which the joined body 70 is manufactured by successively joining them in the vibration welding process will be described.

First, a first vibration welding process is performed to join the second member 72 to the first member 71 by vibration welding. In this case, as shown in FIG. 4, the second member 72 is provided with a plurality of welding ribs 72a for concentrating the vibrational energy due to the lateral vibration on the contact portion between the first member 71 and the second member 72. there is In the first vibration welding process, one of the first member 71 and the second member 72 (for example, the first member 71) is fixed, and the other (for example, the second member 72) is pressed toward one side while vibrating in the horizontal direction. Let As a result, heat is generated by friction at the contact portion between the first member 71 and the second member 72, and the heat melts the synthetic resin, thereby welding the first member 71 and the second member 72 together.

Next, a second vibration welding step is performed to join the third member 73 to the primary joined body in which the first member 71 and the second member 72 are joined by vibration welding. Similar to the second member 72, the third member 73 is provided with a plurality of welding ribs 73a for concentrating vibration energy. Also in the second vibration welding process, as in the first vibration welding process, one member to be joined is fixed and the other member is vibrated while being pressurized. As a result, the joined body 70 in which the first member 71, the second member 72, and the third member 73 are laminated and integrated is manufactured.

However, when the bonded body 70 is manufactured by performing the vibration welding process twice as described above, the thickness of the second member 72 is partially thickened at the portion where the welding rib 72a of the second member 72 is provided. Therefore, during the molding process of molding the second member 72, a sink mark (dent) 72b as shown in FIG.

When the third member 73 is joined to the back surface of the second member 72 on which such sink marks 72b are formed, for example, the welding ribs 73a of the third member 73 and the sink marks 72b on the back surface of the second member 72 are formed. If vibration welding is performed by contacting the portion where the contact is made, the synthetic resin cannot be appropriately melted at the contact portion including the sink mark 72b, so the required welding strength cannot be secured. For this reason, conventionally, when the vibration welding process is performed twice, the welding rib 72a of the second member 72 and the welding rib 73 of the third member 73 are arranged as shown in FIG. 73a are displaced from each other. As a result, in the second vibration welding step, the welding rib 73a of the third member 73 can be brought into contact with the back surface portion of the second member 72 where the sink marks 72b are not formed. 73 can be joined to the second member 72 with an appropriate welding strength.

On the other hand, when the formation position of the welding rib 72a of the second member 72 and the formation position of the welding rib 73a of the third member 73 are shifted in this way, when one bonded body 70 is viewed from the stacking direction, the The total area of the welded portion (welded region) where the first member 71 and the second member 72 are welded and the welded portion (welded region) where the second member 72 and the third member 73 are welded is should be widely secured. However, in order to appropriately secure the welding strength while appropriately securing the area of the welded portion between the members, the arrangement of the welding ribs 72a and 73a is likely to be restricted. It reduced freedom.

Also, for example, by adjusting the size and shape of the welding rib of the second member, it is possible to prevent the occurrence of sink marks on the back surface of the second member during the molding process of the second member. However, when trying to provide the second member with welding ribs of the optimum size and shape that do not cause sink marks, considering the position of the gate at the time of molding, the arrangement of the welding ribs, the shape of the periphery of the welding ribs, etc., each welding The ribs are formed in different sizes and shapes, resulting in difficulty in adjusting the welding machine and increasing manufacturing costs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to limit the arrangement of protrusions such as welding ribs in a joined body in which at least three members are laminated and integrated. To provide a conjugate that can be made difficult.

In order to achieve the above objects, the present invention provides a joined body in which at least a first member, a second member, and a third member are laminated and integrally formed, The first member, the second member, and the third member are each formed of a synthetic resin, and the first member and the second member are joined by at least one first vibration weld formed by vibration welding. The second member and the third member are joined by at least one second vibration weld formed by vibration welding, and at least a part of the first vibration weld and the second vibration weld are joined. At least a part is characterized by being arranged in a position overlapping each other in the stacking direction.

In the joined body according to the present invention, the second member includes at least one projection projecting from the upper surface facing the first member toward the first member, and a recess formed on the lower surface facing the third member. and an internal rib provided in the recess so as to fill a part of the inner space of the recess.

In this case, it is preferable that the concave portion is arranged within a range overlapping the convex portion in the stacking direction.
Moreover, it is preferable that the recessed portion of the second member is formed in a groove shape, and a plurality of the internal ribs are provided for one recessed portion.

According to the joined body of the present invention, the area of the welded portion where the two members are welded to each other when viewed from the stacking direction can be easily narrowed. As a result, the degree of freedom in designing the joined body can be increased. Furthermore, it is possible to suppress a decrease in the welding strength between the two members due to sink marks.

1 is a cross-sectional view schematically showing a joined body according to an example of the present invention; FIG. FIG. 4 is a perspective view showing a portion of the second member before being joined; FIG. 3 is an enlarged perspective view showing a main part on the lower surface side (rear surface side) of the second member shown in FIG. 2; FIG. 4 is a cross-sectional view schematically showing a conventional first member and second member before being joined by vibration welding; FIG. 4 is a cross-sectional view schematically showing a conventional joined body joined by vibration welding;

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiments described below, and various modifications can be made as long as they have substantially the same configuration as the present invention and have the same effects. It is possible. For example, in the following embodiments, a portion in which three members are laminated in a joined body will be mainly described. The size, thickness, shape, etc. of each member forming the joined body are not particularly limited.

FIG. 1 is a cross-sectional view schematically showing a joined body according to this embodiment. FIG. 2 is a perspective view showing a part of the second member before being joined, and FIG. 3 is an enlarged perspective view showing a main part on the lower surface side (rear surface side) of the second member.
In addition, in the present embodiment, the stacking direction in which the three members are stacked is defined as the vertical direction. In this case, with respect to the central second member, the side on which the first member without welding ribs is arranged is the upper side, and the side on which the third member with the welding ribs is arranged is the lower side.

The joined body 1 of the present embodiment is suitably used for members or parts such as exterior members or interior members used in vehicles such as automobiles. The present invention is not limited to this, and the joined body of the present invention can be used for various members or parts to which synthetic resin moldings are applied in the field of automobiles and other fields. It is possible.

The joined body 1 of this embodiment includes a first member 10 made of synthetic resin, which is an object to be welded in vibration welding, a second member 20 made of synthetic resin, which is joined to the first member 10 by vibration welding, and vibration welding. and a third member 30 made of synthetic resin that is joined to the second member 20 by The first member 10, the second member 20, and the third member 30 are each manufactured in a predetermined shape designed in advance by conventionally known injection molding, press molding, or the like.

In this embodiment, the first member 10, the second member 20, and the third member 30 are each made of thermoplastic resin such as polypropylene to which vibration welding can be applied. In this case, the first member 10 and the second member 20, and the second member 20 and the third member 30 are preferably made of a synthetic resin that is compatible with vibration welding. It is more preferable that the -third member 30 is formed of the same thermoplastic resin as the main component.

The first member 10 of this embodiment has, for example, a plate-like shape in which at least a portion of the lower surface is formed flat. In the present invention, the shape and size of the first member are not particularly limited, and can be changed as appropriate according to the use of the joined body. For example, at least part of the first member 10 may be provided with a curved portion or a projecting portion.

The second member 20 of this embodiment includes a second member main body portion 21 arranged to face the first member 10, a plurality of convex portions 22 protruding from the upper surface of the second member main body portion 21, a second It has a plurality of recesses 23 recessed in the lower surface of the member main body 21 and internal ribs 24 provided in each recess 23 . The second member body portion 21 of the present embodiment includes, for example, a portion having a thin plate-like shape. In the present invention, the shape and size of the second member main body are not particularly limited, and can be changed as appropriate according to the use of the joined body.

The convex portion 22 of the second member 20 is formed by a second welding rib 22a protruding in a ridge shape from the upper surface of the second member main body portion 21 . In this embodiment, each of the second welding ribs 22a, before being joined to the first member 10 by vibration welding, is arranged in a first direction orthogonal to the stacking direction of the joined body 1, as shown in FIG. 5 (for example, in the longitudinal direction or the front-rear direction) and is provided linearly and continuously. Also, the plurality of second welding ribs 22a are provided parallel to each other.

Each second welding rib 22a is formed so that a cross section orthogonal to the first direction 5 has a constant shape. For example, in the case of the present embodiment, the second weld rib 22a has a semicircular or nearly semicircular cross section perpendicular to the first direction 5 before being joined to the first member 10. . Each second welding rib 22a is joined to the lower surface of the first member 10 by a first vibration welding portion 6 formed at the boundary between the first member 10 and the second welding rib 22a in a first vibration welding process, which will be described later. ing. In this case, the second weld rib 22a is deformed by pressure and heat during vibration welding, and burrs are generated. It has a shape close to

In the present invention, the shape, size, and arrangement of the second welding ribs, and the protrusion height of the second welding ribs from the upper surface of the second member main body are not particularly limited, and may vary depending on the use of the joined body. It can be changed as appropriate. Moreover, the form of the convex portion of the second member is not limited to a linearly continuous ridge-like shape as long as it is formed so as to protrude from the upper surface of the second member main body portion. For example, when the second member is viewed from above, the convex portion of the second member may be formed in a shape that intermittently extends in one direction (a shape with a break), or in a shape that is curved in an arc shape or a wavy shape.

The recessed portion 23 of the second member 20 is formed by a recessed groove portion 23 a recessed in the lower surface of the second member main body portion 21 . In this embodiment, each concave groove portion 23a is linearly provided along the same direction as the direction in which the second welding rib 22a extends, that is, along the first direction 5 described above. Also, the plurality of recessed grooves 23a are provided parallel to each other.

In the second member 20, each concave groove portion 23a is provided at a position on the opposite side corresponding to one second welding rib 22a provided on the upper surface side of the second member 20. As shown in FIG. In particular, each concave groove portion 23a is provided within a range overlapping in the stacking direction with respect to each corresponding second welding rib 22a. That is, when the second member 20 is viewed in the stacking direction, the formation range of one concave groove portion 23a provided on the bottom surface of the second member 20 is one groove portion provided corresponding to the top surface side of the second member 20. It is arranged inside the formation range of the second welding rib 22a.

In addition, the concave groove portion 23a is the thickness of the portion of the second member 20 excluding the internal rib 24 (the upper surface of the second member main body portion 21 and the second welding rib 22a, and the lower surface of the second member main body portion 21 and the concave groove portion 23a). ) are provided to have a substantially constant size. Specifically, in the second member 20 of this embodiment, the second welding rib 22a protrudes from the upper surface of the second member main body portion 21, so that the concave groove portion 23a is increased by the second welding rib 22a. It is provided corresponding to the second welding rib 22 a so as to absorb the thickness of the two members 20 .

As a result, the portion of the second member 20 excluding the internal ribs 24 can have a substantially constant thin thickness in at least the portion of the second member 20 that is welded to the first member 10 and the vicinity thereof. Since the second member 20 is formed to be thin in this manner, sink marks on the lower surface of the second member 20 (in particular, the portion of the lower surface corresponding to the second welding rib 22a) are prevented in the molding process for molding the second member 20. can be suppressed. In addition, in the first vibration welding step (the step of vibration welding the first member 10 and the second member 20 together), which will be described later, the volume of the melted portion of the second member 20 (melted volume) should be less likely to vary. can be done.

In the present invention, the shape, size, arrangement, etc. of the recess are not particularly limited as long as the recess of the second member is provided corresponding to the protrusion formed on the upper surface side of the second member. For example, when the convex portion of the second member is formed to project from the upper surface of the second member main body portion in an arcuate or wavy curved shape in a plan view of the second member, the concave portion of the second member In order to keep the thickness of the member substantially constant, it is preferable that the concave portion is recessed in the lower surface of the second member main body in an arcuate or wavy curved shape corresponding to the convex portion.

At least one internal rib 24 is provided in each recessed groove portion 23a of the second member 20 so as to partially fill the inner space of the recessed groove portion 23a. In the case of this embodiment, a plurality of internal ribs 24 are provided in each of the plurality of recessed groove portions 23a.

Each internal rib 24 is provided along the second direction perpendicular to the above-described first direction 5 (in other words, the lengthwise direction of the groove 23a) so as to cross the groove 23a. In addition, the lower end surface of each internal rib 24 is formed continuously from the lower surface of the second member main body portion 21, and the lower end surface of the internal rib 24 and the lower surface of the second member main body portion 21 form a boundary therebetween. It is formed on a smooth single surface (flat surface in the case of this embodiment) without forming a step in the portion.

As a result, the area of the smoothly formed lower surface of the second member 20 (especially in the case of the present embodiment, the area of the flat surface that does not include steps, unevenness, etc.) can be reduced to, for example, the case where the internal ribs 24 are not provided at all. can be secured more widely than Furthermore, in this embodiment, since a plurality of internal ribs 24 are provided for one groove 23a, even if the groove 23a is recessed in the lower surface of the second member 20, the area of the lower surface is smooth. It can be easily secured widely. As a result, the third welding rib 32 of the third member 30 can be stably brought into contact with the lower surface of the second member 20 in the second vibration welding process described later for welding the second member 20 and the third member 30 together. This allows the third member 30 to be strongly welded to the second member 20 .

In the present invention, the shape, size, arrangement, etc. of the internal ribs in the second member are not particularly limited. If it is formed, it can be changed as appropriate. For example, when the lower surface of the second member main body is formed into a curved surface, the lower surface of the internal rib is preferably formed into a curved surface that smoothly continues to the curved lower surface of the second member main body.

In this embodiment, the plurality of internal ribs 24 are provided at regular intervals in the longitudinal direction of the concave groove portion 23a (that is, the first direction 5 described above). In this case, the dimension of the internal ribs 24 in the first direction 5 (the thickness of the internal ribs 24 ) is set smaller than the interval between the internal ribs 24 adjacent to each other in the first direction 5 . By forming the internal ribs 24 to be thin in this way, it is possible to make it more difficult for sink marks to occur on the lower surface of the second member 20 in the molding process of the second member 20 .

The third member 30 of this embodiment includes a third member main body portion 31 arranged to face the second member 20 and at least one third welding rib (convex rib) projecting from the upper surface of the third member main body portion 31. part) 32. In this embodiment, the third welding rib 32 is provided parallel to the second welding rib 22a, that is, along the first direction 5 described above.

Before being joined to the second member 20 , the third weld rib 32 has a semicircular or nearly semicircular cross section perpendicular to the first direction 5 . Further, in the case of this embodiment, the third welding rib 32 has a smaller dimension in the longitudinal direction than the second welding rib 22 a , and a part of the third welding rib 32 extends into the groove 23 a of the second member 20 . formed so as to be insertable inside.

The third welding rib 32 is joined to the lower surface of the second member 20 by the second vibration welding portion 7 formed at the boundary between the second member 20 and the third welding rib 32 in a second vibration welding step to be described later. there is In the present invention, the shape and size of the third member and the shape, size, arrangement, etc. of the third welding rib are not particularly limited, and can be appropriately changed according to the use of the joined body. be.

Next, by performing vibration welding on the first member 10, the second member 20, and the third member 30, the joined body 1 in which the first member 10 to the third member 30 are laminated in order and integrated. will be described.
In this embodiment, first, a preparatory step of preparing the first member 10, the second member 20, and the third member 30 is performed. Subsequently, using the prepared first member 10 and second member 20, a first vibration welding step is performed in which the second member 20 is joined to the first member 10 by vibration welding to form a primary joined body. After that, a second vibration welding step is performed to join the prepared third member 30 to the lower surface of the second member 20 in the obtained primary joined body by vibration welding. Thus, the joined body 1 is manufactured.

In the preparation step, for example, the first member 10, the second member 20, and the third member 30 are molded into predetermined shapes designed in advance by injection molding or the like. At this time, the second member 20 is provided with a plurality of recessed grooves 23a corresponding to the second welding ribs 22a on the lower surface side of the second member 20, so that the portion of the second member 20 excluding the internal ribs 24 is , is thin and formed with a substantially constant thickness, it is possible to effectively suppress the occurrence of sink marks on the lower surface of the second member 20 obtained after the molding process.

Next, in the first vibration welding step, vibration welding is performed on the first member 10 and the second member 20 using a vibration welding machine. In this embodiment, for example, the first member 10 is fixed to the vibration welding machine, and the second member 20 is brought into contact with the first member 10 . At this time, each second welding rib 22 a of the second member 20 is brought into contact with the lower surface of the first member 10 . Further, the second member 20 is pressed toward the first member 10 to press the contact portion between the first member 10 and the second welding rib 22a, and the second member 20 is moved in the lateral direction orthogonal to the pressing direction. vibrate. In this embodiment, the second member 20 vibrates in the direction along the second welding rib 22a (first direction 5 described above) or in the direction orthogonal to the second welding rib 22a (second direction described above). will be In the present invention, the vibration direction of vibration welding is not particularly limited. Further, in the present invention, in the first vibration welding step, the second member 20 may be fixed to the vibration welding machine, and the first member 10 may be pressed toward the second member 20 to vibrate.

By performing the pressurization and vibration described above in the first vibration welding step, the contact portion between the lower surface of the first member 10 and the second welding rib 22a of the second member 20 can be melted by frictional heat, and then Then, the molten synthetic resin is cooled to form the first vibration welded portion 6 , and the first member 10 and the second member 20 are joined by the first vibration welded portion 6 . At this time, the welding strength between the first member 10 and the second member 20 can be adjusted by changing the volume of the synthetic resin to be melted. Thereby, a primary joined body (not shown) in which the first member 10 and the second member 20 are laminated and integrated can be manufactured.

After completion of the first vibration welding process, a second vibration welding process is performed to join the primary joined body obtained in the first vibration welding process and the third member 30 . In this second vibration welding step, for example, the primary joined body is fixed to a vibration welding machine, and the third welding rib 32 of the third member 30 is brought into contact with the lower surface of the second member 20 of the primary joined body. At this time, as shown in FIG. 3, on the lower surface of the second member 20, a plurality of internal ribs 24 are provided so as to cross the recessed grooves 23a, and are arranged at regular intervals in the recessed grooves 23a. As a result, a large planar area is secured on the lower surface of the second member 20 . Therefore, in the second vibration welding process, the third welding rib 32 of the third member 30 can be stably and easily brought into contact with the lower surface of the second member 20 .

Also, in this embodiment, the occurrence of sink marks on the lower surface of the second member 20 is suppressed when the second member 20 is molded. Therefore, when the third member 30 is brought into contact with the primary joined body, the contact portion between the lower surface of the second member 20 and the welding rib of the third member 30 is formed between the first member 10 and the second member 20. Even if it is arranged so as to overlap with the first vibration welding part 6 in the stacking direction, it is possible to prevent the welding strength from being lowered as in the case of the conventional vibration welding.

After the third member 30 is brought into contact with the primary joined body as described above, the third member 30 is pressed toward the primary joined body to pressurize the contact portion between the second member 20 and the third welding rib 32, Vibration welding is performed by vibrating the third member 30 in a lateral direction orthogonal to the pressing direction. In the case of this embodiment, the third member 30 is vibrated in the direction along the third welding rib 32 or in the direction orthogonal to the third welding rib 32 . At this time, similarly to the first vibration welding step, the welding strength between the second member 20 and the third member 30 can be adjusted by changing the melted volume of the synthetic resin.

By performing the vibration welding described above, the contact portion between the lower surface of the second member 20 and the third welding rib 32 of the third member 30 can be melted by frictional heat, and then the melted synthetic resin is cooled. As a result, the second vibration welded portion 7 is formed, and the second member 20 and the third member 30 are joined by the second vibration welded portion 7 . As a result, the lower surface of the second member 20 and the upper end portion of the third welding rib 32 of the third member 30 in the primary joined body are joined by the second vibration welding portion 7, and the first member 10, the second member 20, The joined body 1 of FIG. 1 in which the third member 30 is laminated and integrated can be manufactured. In the present invention, in the second vibration welding step, the third member may be fixed to the vibration welding machine, and the primary joined body may be pressed toward the third member and vibrated. In the present invention, the order of performing vibration welding is not particularly limited. For example, after preparing the first member 10 to the third member 30, the second member 20 and the third member 30 are first joined by vibration welding, and then joined. The second member 20 and the third member 30 may be joined to the first member 10 by vibration welding, or the first to third members 10 to 30 may be joined by vibration welding at the same time.

According to the joined body 1 of the present embodiment manufactured as described above, it is possible to suppress the occurrence of sink marks on the lower surface of the second member 20 during molding (during fabrication) of the second member 20, and By providing the internal ribs 24 in the member 20, a large area of the flat lower surface of the second member 20 can be ensured. For this reason, the joined body 1 of the present embodiment includes at least a portion of the first vibration welding portion 6 that joins the first member 10 and the second member 20 together, and a second vibration welding portion that joins the second member 20 and the third member 30 together. At least part of the vibration welded portion 7 can be formed in a positional relationship in which the first member 10 to the third member 30 overlap each other in the stacking direction. By thus forming the joined body 1 by superimposing the first vibration-welded part 6 and the second vibration-welded part 7 in the stacking direction, it is possible to make it difficult to restrict the arrangement of the welding ribs. Thus, the degree of freedom in designing the joined body 1 can be increased.

Further, in the joined body 1 of the present embodiment, the joined body 1 is reduced compared to the conventional case in which the first vibration welded portion and the second vibration welded portion are arranged so as not to overlap each other while ensuring the required welding strength. The total area of the first vibration welding part 6 and the second vibration welding part 7 when viewed from the lamination direction is greatly reduced (in other words, the first vibration welding part 6 and the second vibration welding part 7 are ), and the space saving of the first vibration welding part 6 and the second vibration welding part 7 in the plane orthogonal to the stacking direction can be realized. Since the first vibration-welding part 6 and the second vibration-welding part 7 can be superimposed and arranged in a narrower area, it is possible to easily reduce the size of the joined body 1 .

Furthermore, in the joined body 1 of the present embodiment, even if the first vibration welding part 6 and the second vibration welding part 7 overlap each other in the stacking direction of the first member 10 to the third member 30, when the second member 20 is molded, The occurrence of sink marks on the two members 20 can be suppressed. For this reason, as in the case of stacking and integrating three members by conventional vibration welding, the welding strength of the joined body may decrease due to the sink mark of the second member arranged in the center of the lamination direction. can be effectively suppressed.

In the above-described embodiment, the three members, ie, the first member 10 to the third member 30 are laminated in order to manufacture the joined body 1. However, in the present invention, four or more members are laminated in order. and the conjugate may have been manufactured. For example, when four members, ie, the first member to the fourth member, are laminated in order to manufacture a joined body, the second member and the third member that are sandwiched between and joined to the two members are each subjected to By providing a convex portion (welding rib), a concave portion (concave groove portion) corresponding to the convex portion, and an internal rib provided in the concave portion as described in the example, the second member and the third member are provided with the respective members. It is possible to suppress the occurrence of sink marks in the molding process. In addition, it is difficult to restrict the arrangement of the welding ribs in the second to fourth members, and as a result, it is possible to increase the degree of freedom in designing the joined body and to make it easier to reduce the size of the joined body. Furthermore, in the present invention, the order of performing vibration welding is not limited as described above, and all four or more members may be joined simultaneously by vibration welding.

1 joined body 5 first direction 6 first vibration welding part 7 second vibration welding part 10 first member 20 second member 21 second member body part 22 convex part 22a second welding rib 23 concave part 23a concave groove part 24 internal rib 30 Third member 31 Third member main body 32 Third welding rib (projection)

Claims (4)

A joined body in which at least a first member, a second member, and a third member are laminated and integrally formed,
The first member, the second member, and the third member are each formed of a synthetic resin,
The first member and the second member are joined by at least one first vibration weld formed by vibration welding,
the second member and the third member are joined by at least one second vibration weld formed by vibration welding;
A joined body, wherein at least a portion of the first vibration welding portion and at least a portion of the second vibration welding portion are arranged to overlap each other in a stacking direction. The second member includes at least one protrusion projecting from an upper surface facing the first member toward the first member, at least one recess formed in a lower surface facing the third member, 2. The joined body according to claim 1, further comprising an internal rib provided in said recess so as to partially fill an inner space of said recess. 3. The joined body according to claim 2, wherein said concave portion is arranged within a range overlapping said convex portion in said stacking direction. The recess of the second member is formed in a groove shape,
4. The joined body according to claim 2, wherein a plurality of said internal ribs are provided for one said recess.

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