JP2020185669A - Manufacturing method of resin bonded body and resin bonded body - Google Patents

Abstract

To provide a resin bonded body having high bonding accuracy and high bonding strength.SOLUTION: When joining a first member 31 having a protrusion 51 and a second member 32 comprising a stepped groove 60 having (a) a large width portion 61 on a contact surface side larger than a width of the protrusion 51, (b) a small width portion 62 on a bottom side smaller than the width of the protrusion 51 and (c) a stepped portion 63 that connects the large width portion 61 and the small width portion 62 to form a stepped portion, a manufacturing method of a resin bonded body applies ultrasonic vibration to one of the first member 31 and the second member 32 to melt a portion where the protrusion 51 and the groove 60 are in contact so as to weld the first member 31 and the second member 32 in a state where the protrusion 51 is inserted into the groove 60 to contact a tip portion 53 of the protrusion 51 with the step portion 63.SELECTED DRAWING: Figure 5

Description

The present invention relates to a method for producing a resin bonded body in which two members made of a thermoplastic resin are bonded to each other, and also relates to a resin bonded body.

The following Patent Document 1 describes a configuration in which a vehicle interior material is joined to a duct member by ultrasonic welding. When joining two members by ultrasonic welding, generally, a rib is formed on one member, and the tip of the rib is brought into contact with the other member, and ultrasonic waves are applied to one of the two members. The two members are welded by applying vibration and melting the thermoplastic resin at the portion in contact with the heat generated by the ultrasonic vibration.

JP-A-2019-26193

Since the other of the two members with which the ribs are brought into contact is a flat surface, when ultrasonic vibration is applied, deviation is likely to occur in the direction along the flat surface. Further, since the molten rib is interposed between the first member and the second member, there is a possibility that the joining accuracy of the joined body of these two members may vary due to the variation in the thickness of the molten thermoplastic resin and the like. .. In addition, since the bonding area is relatively small, ultrasonic welding may not be applicable when bonding strength is required.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a resin bonded body having high bonding accuracy and high bonding strength.

In order to solve the above problems, the method for producing a resin bonded body of the present invention is:
A method for manufacturing a resin bonded body in which a first member and a second member molded from a thermoplastic resin are joined by ultrasonic welding.
The first member is provided with a ridge extending along a contact surface with the second member and projecting from the contact surface.
The second member extends along a contact surface with the first member, and has a large portion on the contact surface side larger than the width of the ridge, a narrow portion on the bottom surface side smaller than the width of the ridge, and the large portion. It is assumed that a stepped groove having a stepped portion for connecting the portion and the narrow portion to form a stepped portion is provided.
The ridge is inserted into the groove and the tip of the ridge is brought into contact with the step portion, and ultrasonic vibration is applied to one of the first member and the second member. It is characterized in that the portion in contact with the groove and the groove is melted, and the first member and the second member are welded together.

In this manufacturing method, ultrasonic vibration is applied in a state where the ridge of the first member is inserted into the groove of the second member, so that the first member and the second member are displaced in a horizontal direction with respect to the contact surface. It is possible to manufacture a resin bonded body with high bonding accuracy because it can be bonded at an appropriate position. Further, in this manufacturing method, ultrasonic vibration is started in a state where the ridge is in contact with the stepped portion of the groove, so that the contact area between the first member and the second member is relatively small. be able to. As a result, the ultrasonic vibration can be concentrated and the two members can be efficiently welded. Further, in this manufacturing method, a cavity is formed in the groove by a narrow portion in a state where the ridge and the step portion are in contact with each other, so that the molten thermoplastic resin can flow into the groove. As a result, the thermoplastic resin does not stay between the ridge and the step portion, and while the ultrasonic vibration is applied, the ridge and the step portion are brought into contact with each other to efficiently weld the two members. be able to.

In the above manufacturing method, it is also possible that the volume of the ridge before melting is equal to the volume of the groove.

In this manufacturing method, when a part of the ridge and a part of the groove are melted by ultrasonic vibration, and the molten thermoplastic resin and the ridge are completely contained in the groove, the first step is made. The contact surface of the first member and the contact surface of the second member come into contact with each other. That is, according to this manufacturing method, the molten thermoplastic resin may protrude from between the first member and the second member, or the molten thermoplastic resin may not spread inside the groove and a cavity may be formed inside the groove. It is possible to suppress the occurrence of such a situation. Therefore, according to this manufacturing method, the first member and the second member can be joined accurately and reliably.

Further, in the above manufacturing method, the ridge is erected perpendicularly to the contact surface of the first member, and the large portion of the groove is with the contact surface of the second member. It can also be characterized by having a shape having a pair of vertical inner walls.

In this manufacturing method, since the ridges formed in the shape of a wall are sandwiched between a pair of inner wall surfaces, it is possible to reliably prevent the first member and the second member from being displaced during ultrasonic welding.

Further, in the above manufacturing method, the ridge has a tapered portion whose width becomes smaller toward the tip, and the tapered portion is in contact with the inner edge of the step portion in the groove, and the taper portion. It is also possible to apply ultrasonic vibration in a state where the portion is in contact with the inner edge of the step portion.

In this manufacturing method, the stepped portion (specifically, the stepped surface that faces the inside of the groove in the stepped portion) may be, for example, parallel to the contact surface or inclined with respect to the contact surface. .. However, when it is inclined with respect to the contact surface, the angle formed by the taper portion (specifically, the tapered surface which is the surface facing outward in the tapered portion) is looser than the angle formed with respect to the contact surface. Just do it. Then, in this manufacturing method, the ridge and the groove are in contact with each other only at the two line-shaped portions. That is, according to this manufacturing method, the contact area between the first member and the second member before applying the ultrasonic vibration can be made smaller, and the ultrasonic vibration can be concentrated to make the two members more efficient. Can be welded.

Further, in order to solve the above problems, the resin bonded body of the present invention can be used.
A resin joint in which the first member and the second member molded from a thermoplastic resin are joined by ultrasonic welding.
The joint portion, which is a portion where the first member and the second member are joined,
A convex portion formed on the first member, extending along a joint portion between the first member and the second member, and projecting toward the second member.
A stepped shape formed on the second member, extending along the joint portion, having a large portion on the opening side having a relatively large width and a narrow portion on the bottom surface side having a relatively small width. A concave portion formed and into which the convex portion is inserted,
A molten resin forming portion formed by filling a thermoplastic resin melted by ultrasonic vibration between the convex portion and the concave portion,
It is characterized in that it is configured to include.

In the resin bonded body having this configuration, the first member and the second member are joined by welding between the convex portion formed on the first member and the concave portion of the second member into which the convex portion is inserted. There is. The convex portion of the first member in the resin joint having this configuration is the portion of the above-mentioned ridges that did not melt during ultrasonic welding, and the concave portion of the second member melts during ultrasonic welding of the groove described above. You can think of each as the part you did not do. Since the resin bonded body having this configuration is welded with the convex portion of the first member inserted into the concave portion of the second member, the displacement between the first member and the second member is suppressed and the bonding accuracy is high. It has become a thing. Further, since the convex portion and the concave portion are welded, for example, the welding area can be increased as compared with the case where the first member is welded to the second member having no concave portion, and the first The joint strength between the member and the second member can be increased.

Further, in the above configuration, at least one of the first member and the second member can be made of a highly transparent thermoplastic resin.

Since at least one of the first member and the second member is transparent, the joint portion can be seen when they are joined, for example, when a boss or the like is used, the boss or the like can be seen through. become. Therefore, if ultrasonic welding is used to join the transparent first member and the second member, the traces of the joining can be made inconspicuous. Further, since it is transparent, when the two members are joined in a state of being displaced, the deviation is also easily noticeable. Therefore, the resin joint having the above structure is particularly effective for the joint using the transparent member.

According to the present invention, it is possible to provide a resin bonded body having high bonding accuracy and high bonding strength.

It is a figure which shows the vehicle equipped with the vehicle lighting device using the resin composite of the Example of this invention from the viewpoint from the vehicle interior. It is a front view from the vehicle interior side of the vehicle lighting device shown in FIG. It is sectional drawing which shows from the viewpoint from the vehicle rear of the vehicle lighting device shown in FIG. It is a figure which shows the manufacturing method of the housing as the resin composite body of this Example shown in FIG. 3, and is the figure which shows the state before welding of two members. It is a figure which shows the state which performs ultrasonic welding. It is a figure which shows the state after welding.

Hereinafter, examples of the present invention will be described in detail as embodiments for carrying out the present invention with reference to the drawings. The present invention is not limited to the following examples, and can be carried out in various embodiments with various modifications and improvements based on the knowledge of those skilled in the art.

The resin joint of the embodiment of the present invention is used in a vehicle lighting device 10 (hereinafter, may be simply referred to as "lighting device 10") mounted on a vehicle. The vehicle equipped with the lighting device 10 is shown in FIG. 1 from the viewpoint from the vehicle interior. The lighting device 10 is provided on the door trim 14 as an interior material for a vehicle constituting the vehicle interior surface of the side door 12. The side doors 12 are provided on the driver's seat side (right side in the vehicle width direction) and the passenger seat side (left side in the vehicle width direction), respectively, and rotate around a rotation axis generally extending in the vertical direction on the front side of the vehicle. , It is configured to be openable and closable. The lighting device 10 is provided on both the side door 12 on the driver's seat side and the side door 12 on the passenger's seat side. Since these two lighting devices 10 have the same configuration, in the following description, the lighting devices 10 provided on the driver's side side door 12 and the driver's side side door 12 will be described as representatives. I will do it.

The door trim 14 constitutes a portion of the side door 12 on the vehicle interior side, and is attached to the door inner panel from the vehicle interior side. As shown in FIG. 1, the door trim 14 is arranged below the window 16, and includes a lower board 14A, an upper board 14B, and a lighting device 10. An armrest 18 is formed at the upper end of the lower board 14A, and the lighting device 10 is arranged above the armrest 18.

As shown in FIG. 2, the lighting device 10 includes two light emitting units 20 that can be turned on and off. Each light emitting unit 20 includes a light source 21 and a light guide rod (light guide body) 22. The light emitting unit 20 is capable of controlling the lighting state. Specifically, the light source 21 is mainly composed of an LED whose illuminance, light color, etc. can be changed within a certain range, and can be switched on and off, and is relative when lit. It is possible to change the illuminance step by step in the range from bright high illuminance to dark low illuminance. Further, the light source 21 has LED elements whose emission colors are red, green, and blue, respectively, and it is possible to change the light color according to the mixing ratio of each emission color.

The light guide rod 22 is made of a longitudinal light guide material. The light guide material is a synthetic resin material that is substantially transparent and allows light to pass through, and in this embodiment, it is an acrylic resin. The light guide rod 22 is arranged so that one end in the longitudinal direction faces the light source 21, and the light of the light source 21 is incident from the one end. The light guide rod 22 is configured such that the incident light is guided by repeating total internal reflection inside, and a part of the light to be guided is emitted from the outer peripheral surface.

The lighting device 10 includes a housing 30 that houses the light guide rods 22 of each light emitting unit 20 inside. As shown in FIG. 2, the housing 30 has a generally rectangular shape in a plan view, is fixed between the lower board 14A and the upper board 14B constituting the door trim 14, and one surface of the housing 30 is a vehicle interior surface. It forms a part. As shown in FIG. 3, the housing 30 is generally box-shaped, and is composed of a first housing member 31 forming a portion on the vehicle interior side and a second housing member 32 forming a portion on the outside of the vehicle interior. Become. More specifically, the second housing member 32 has a bottom surface portion 33 (a portion outside the vehicle interior) and a wall portion 34 erected from the peripheral edge of the bottom surface portion 33, and is generally a dish-shaped member. There is. On the other hand, the first housing member 31 is a lid-shaped member that closes the opening of the dish-shaped second housing member 32. Specifically, the first housing member 31 has the same outer shape as the second housing member 32 from the viewpoint in the vehicle interior / exterior direction, and is joined to the tip of the wall portion 34 of the second housing member 32 at the peripheral edge. ing.

First, the first housing member 31 is made of a highly translucent synthetic resin (for example, acrylic, PET, polycarbonate), and is capable of transmitting the light of the light emitting unit 20 toward the vehicle interior. In this embodiment, the first housing member 31 is made of polycarbonate, which is a thermoplastic resin. Further, a film 40 for enhancing the design is attached to the outer surface of the vehicle interior of the first housing member 31. On the other hand, the second housing member 32 is made of ABS resin, which is a thermoplastic resin. The second housing member 32 has a reflective layer 41 that mirror-reflects light on the surface of the bottom surface 33 on the vehicle interior side. The reflective layer 41 is made of a metal film such as aluminum, and is formed on the surface of a base material made of ABS resin by, for example, vapor deposition. The light guide rods 22 of the two light emitting units 20 described above are located along the upper end corners and the lower end corners of the second housing member 32, in other words, outside the passenger compartment at the upper and lower ends of the housing 30. It is arranged along.

The first housing member 31 and the second housing member 32 made of these thermoplastic resins are joined by ultrasonic welding to form the housing 30. That is, the housing 30 is the resin joint of the present embodiment. Next, also refer to FIGS. 4 to 6 for a method of manufacturing the housing 30 as the resin joint body of the present embodiment, specifically, a method of joining the first housing member 31 and the second housing member 32. While doing so, I will explain in detail.

In the housing 30, which is the resin joint of the present embodiment, the joint portion 50 between the first housing member 31 and the second housing member 32 is arranged along the peripheral edge as shown in FIG. That is, in the first housing member 31, the outer surface of the vehicle interior of the peripheral portion is the contact surface 31A with respect to the second housing member 32, and in the second housing member 32, the tip surface of the wall portion 34 (the surface facing the vehicle interior side). ) Is the contact surface 32A with respect to the first housing member 31. The first housing member 31 and the second housing member 32 are joined in a state where the contact surface 31A and the contact surface 32A are in contact with each other.

First, the shape of the first housing member 31 and the second housing member 32 before being joined will be described. The first housing member 31 includes a ridge 51 that extends along the contact surface 31A and projects from the contact surface 31A. As shown in FIG. 4, the ridge 51 is provided at a wall-shaped standing wall portion 52 that stands perpendicular to the contact surface 31A and at the tip of the standing wall portion 52, and the width becomes smaller toward the tip. It has a tapered portion (tip portion) 53. The tip of the tapered portion 53, that is, the tip of the ridge 51 has a cross-sectional shape and a sharp shape.

On the other hand, the second housing member 32 includes a groove 60 extending along the contact surface 32A. As shown in FIG. 4, the groove 60 is smaller than the width of the large portion 61 on the contact surface 32A side (opening side) having a width larger than the width of the ridge 51 and the width of the ridge 51. It has a stepped shape having a narrow portion 62 on the bottom surface side having a width, and a step portion 63 forming a step by connecting the large portion 61 and the narrow portion 62. More specifically, the groove 60 has a shape that is recessed perpendicular to the contact surface 32A, that is, a shape in which the large portion 61 and the narrow portion 62 have a pair of inner wall surfaces 61A and 62A perpendicular to the contact surface 32A. There is.

Then, when joining the first housing member 31 as the first member and the second housing member 32 as the second member molded as described above, first, the protrusion of the first housing member 31 is formed. 51 is inserted into the groove 60 of the second housing member 32. Although the stepped portion 63 of the groove 60 (specifically, the stepped surface 63A which is a surface facing the inside of the stepped portion 63) is inclined with respect to the contact surface 32A, the inclination gradient θ ₂ is shown in FIG. As shown in the above, the taper portion 53 in the ridge 51 (specifically, the taper surface 53A which is a surface facing the outside of the taper portion 53) is made smaller than the inclination gradient θ ₁ . Therefore, when the ridge 51 is inserted into the groove 60, as shown in FIG. 5, the ridge 51 and the groove 60 are in a state where the tapered portion 53 is in contact with the inner edge of the step portion 63. That is, the ridge 51 and the groove 60 are in contact with each other only at the two line-shaped portions.

Subsequently, ultrasonic vibration is applied using the tool horn 70 in a state where the first housing member 31 and the second housing member 32 are in contact with each other. More specifically, the tool horn 70 is brought into contact with the first housing member 31 from the side surface of the vehicle interior, pressure is applied from the first housing member 31 toward the second housing member 32, and ultrasonic vibration is generated. Granted. When the ultrasonic vibration starts to be applied, the ultrasonic vibration concentrates on the contact portion between the ridge 51 and the groove 60, specifically, the contact portion between the tapered portion 53 and the step portion 63, and heat is generated. At the contact portion, the thermoplastic resin forming the ridge 51 and the groove 60 begins to melt.

In the manufacturing method of this embodiment, the ridge 51 is inserted into the groove 60, and more specifically, the standing wall portion 52 of the ridge 51 is sandwiched between the pair of inner wall surfaces 61A of the large portion 61. Since ultrasonic vibration is applied, the first housing member 31 and the second housing member 32 do not deviate in the directions along the contact surfaces 31A and 32A. That is, the accuracy of the joining position between the first housing member 31 and the second housing member 32 is high, and the housing 30, which is the resin joint body of this embodiment, has high joining accuracy.

Further, in the present embodiment, as described above, the first housing member 31 and the second housing member 32 are in contact with each other only at the two line-shaped portions, and the contact area is relatively small. Therefore, when the ultrasonic vibration is started to be applied, the ultrasonic vibration can be concentrated on the line-shaped portion, and the ultrasonic energy can be used efficiently. Further, the molten thermoplastic resin can flow toward the bottom surface side of the groove 60, that is, can flow into the narrow portion 62. As a result, a large amount of molten thermoplastic resin does not stay between the tapered portion 53 and the stepped portion 63, and the tapered portion 53 and the stepped portion 63 are surely brought into contact with each other to use ultrasonic energy more efficiently. can do. From the above, according to the manufacturing method of the present embodiment, ultrasonic energy can be efficiently used to efficiently perform bonding by welding.

Further, in this embodiment, the first housing member 31 and the second housing member 32 are formed so that the volume of the ridge 51 is equal to the volume of the groove 60. Therefore, as shown in FIG. 6, when the molten thermoplastic resin and the ridge 51 (partially melted) are completely contained in the inside of the groove 60 (partially melted). , The contact surface 31A of the first housing member 31 and the contact surface 32A of the second housing member 32 come into contact with each other. That is, according to the manufacturing method of the present embodiment, the molten thermoplastic resin protrudes from between the first housing member 31 and the second housing member 32, or the molten thermoplastic resin does not reach the inside of the groove 60 and is grooved. It is possible to suppress the occurrence of a situation in which a cavity is formed inside the 60. Therefore, according to the manufacturing method of the present embodiment, the first housing member 31 and the second housing member 32 can be joined accurately and reliably.

In the housing 30 manufactured by the above manufacturing method, as shown in FIG. 6, a joint portion 50 between the first housing member 31 and the second housing member 32 is formed in the first housing member 31 and is formed in the joint portion 50. A convex portion 80 extending along and protruding toward the second housing member 32, and a large portion 61 on the opening side formed on the second housing member 32 and extending along the joint portion 50 and having a relatively large width. The concave portion 81 formed in a stepped shape having a narrow portion 62 on the bottom surface side whose width is relatively small and into which the convex portion 80 is inserted, and the thermoplastic resin melted by ultrasonic vibration form the convex portion 80. It is configured to include a molten resin forming portion 82 formed by filling between the recess 81 and the recess 81. Incidentally, the convex portion 80 can be considered to be formed by melting a part of the ridge 51, and the concave portion 81 can be considered to be formed by melting a part of the groove 60. For ultrasonic welding of the two members, a method of applying ultrasonic vibration in a state where the ribs formed on one of the two members are in contact with the joint surface of the other is generally used. The housing 30 in this embodiment has a larger welding area and a higher bonding strength between the first housing member 31 and the second housing member 32 as compared with the resin bonded body bonded by such a method. It has become.

Further, in the housing 30, since the first housing member 31 is a highly transparent thermoplastic resin, the joint portion 50 can be seen through, but the housing 30 of this embodiment has a recess due to ultrasonic welding. Since the inside of 81 is also filled with the thermoplastic resin, the traces of joining can be made inconspicuous.

The resin joint of this embodiment has been used for the interior material of a vehicle (lighting device for a vehicle), but is not limited to this, and can be widely adopted for a joint of two members made of a thermoplastic resin. The method for producing a resin bonded body can be widely adopted when manufacturing a resin bonded body by joining two members made of a thermoplastic resin.

10 ... Vehicle lighting device, 30 ... Housing [resin joint], 31 ... First housing member [first member], 31A ... Contact surface, 32 ... Second housing member [second member], 32A ... Contact surface, 50 ... joint, 51 ... ridge, 52 ... standing wall, 53 ... tapered, 60 ... groove, 61 ... large part, 61A ... inner wall surface, 62 ... narrow part, 63 ... stepped part, 70 ... tool horn, 80 … Convex part, 81… concave part, 82… molten resin forming part

Claims (6)

A method for manufacturing a resin bonded body in which a first member and a second member molded from a thermoplastic resin are joined by ultrasonic welding.
The first member is provided with a ridge extending along a contact surface with the second member and projecting from the contact surface.
The second member extends along a contact surface with the first member, and has a large portion on the contact surface side larger than the width of the ridge, a narrow portion on the bottom surface side smaller than the width of the ridge, and the large portion. It is assumed that a stepped groove having a stepped portion for connecting the portion and the narrow portion to form a stepped portion is provided.
By inserting the ridge into the groove and applying ultrasonic vibration to one of the first member and the second member in a state where the tip portion of the ridge is in contact with the step portion, the ridge is applied. A method for producing a resin bonded body, which comprises melting a portion in contact with the groove and welding the first member and the second member. The method for producing a resin bonded body according to claim 1, wherein the volume of the ridge and the volume of the groove before melting are equal to each other. The ridge is to be erected perpendicular to the contact surface of the first member, and the large portion of the groove has a pair of inner wall surfaces perpendicular to the contact surface of the second member. The method for producing a resin bonded body according to claim 1 or 2, which has a shape. The ridge has a tapered portion whose width becomes smaller toward the tip, and the tapered portion is in contact with the inner edge of the step portion in the groove.
The method for manufacturing a resin joint according to claim 3, wherein ultrasonic vibration is applied in a state where the tapered portion is in contact with the inner edge of the step portion. A resin joint in which the first member and the second member molded from a thermoplastic resin are joined by ultrasonic welding.
The joint portion, which is a portion where the first member and the second member are joined,
A convex portion formed on the first member, extending along a joint portion between the first member and the second member, and projecting toward the second member.
A stepped shape formed on the second member, extending along the joint portion, having a large portion on the opening side having a relatively large width and a narrow portion on the bottom surface side having a relatively small width. A concave portion formed and into which the convex portion is inserted,
A molten resin forming portion formed by filling a thermoplastic resin melted by ultrasonic vibration between the convex portion and the concave portion,
A resin joint characterized by being composed of. The resin joint according to claim 5, wherein at least one of the first member and the second member is formed of a highly transparent thermoplastic resin.

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