JP2010105351A - Vibration-welded structure of resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin molding in which two resin-made panels are unified firmly by vibration welding and which is reduced in its own weight. <P>SOLUTION: A hard, thin-walled solid layer 25 with high resin density is formed on the front and back surfaces of a panel body 21 of a front panel 17, and a foamed layer 27 which is sandwiched by the solid layer 25 and has a large number of voids inside and whose resin density is lower than that of the solid layer 25 is formed in the panel body 21. A welding rib 41 made of a solid is integrally protruded on the back side of a rear panel 19 to be stretched in the vibration direction during vibration welding. The front end of the welding rib 41 is made to penetrate the solid layer 25 on the back side of the panel body 21 of the front panel 17 to intrude into the foamed layer 27 so that the foamed layer 27 and the back side solid layer 25 are welded together and unified. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a vibration welded structure of a resin molded product obtained by fusing and integrating a resin first panel and a resin second panel in a state where they are pressed against each other.

  Conventionally, a resin panel having a single-layer structure composed of only a solid layer or a two-layer structure in which a foam layer is integrally provided inside an outer solid layer is known.

Patent Document 1 discloses a lid of a glove box that is attached to an instrument panel of an automobile as a vibration welded structure of a resin molded product. This lid is composed of a lid inner panel and a lid outer panel, and both the panels have a single-layer structure consisting of only a solid layer. A plurality of welding ribs are integrally projected on the back surface of the lid inner panel so as to extend in the vibration direction at the time of vibration welding, and the lid is vibrated in a state where the front surface of the welding rib is pressed against the back surface of the lid outer panel. The inner panel and lid outer panel are welded together.
JP 2004-58468 A

  However, when only the front end surface of the welding rib is welded to the back surface of the lid outer panel as in Patent Document 1, the welding strength may be insufficient depending on the structure of the resin molded product, the number of welding ribs, and the like. Further, since the lid inner panel and the lid outer panel have a single-layer structure including only a solid layer, the weight of the lid increases.

  This invention is made | formed in view of this point, The place made into the objective is to obtain the resin molded product reduced in weight while firmly integrating two resin panels by vibration welding.

  In order to achieve the above object, the present invention is characterized in that at least one panel employs a two-layer structure of a solid layer and a foam layer, and the foam layer of the one panel is used as a welding location.

  Specifically, the present invention is directed to a vibration welded structure of a resin molded product that is integrally welded by vibrating in a state where the first resin panel and the second resin panel are in pressure contact with each other. I took the right solution.

  In other words, the invention according to claim 1 is that the first panel includes a thin solid layer formed on the front and back surfaces, and a foam layer sandwiched between the solid layers and having a large number of voids inside. The second panel has a panel body integrally projected on the back surface so that the welding rib made of solid extends in the vibration direction at the time of vibration welding, and the tip of the welding rib is at the time of vibration welding. The panel main body back side solid layer of the said 1st panel is penetrated, it penetrates into a foam layer, and this foam layer and solid layer are welded and integrated, It is characterized by the above-mentioned.

  According to a second aspect of the present invention, in the vibration welded structure of the resin molded product according to the first aspect, the panel body of the second panel is sandwiched between a thin solid layer formed on the front and back surfaces and the solid layer. And a foamed layer having a large number of voids inside.

  According to a third aspect of the present invention, in the vibration welded structure for a resin molded product according to the second aspect, a solid formed on the front and back surfaces of the panel main body is provided at a position where the welding rib protrudes from the panel main body of the second panel. A base layer made of a solid thicker than the layer is formed so as to integrally connect the solid layers on the front and back surfaces of the panel body, and the weld rib protrudes integrally from the base layer. Features.

  According to the first aspect of the present invention, since the front end of the welding rib penetrates into the foam layer of the first panel and is welded and integrated not only with the solid layer on the back side of the panel body but also with the foam layer, the surface of the solid layer Compared with the case where welding is carried out only, the welding area is increased, and a high welding strength can be obtained. As a result, wobbling of the welding rib is prevented, and the coupled state of the first panel and the second panel is reliably stabilized.

  Furthermore, since the inside of the panel body of the first panel is formed of a foam layer, the weight of the resin molded product is reduced (weight reduction) compared to the case where the first panel is formed of only a solid layer, and the resin Material costs are reduced.

  According to the invention which concerns on Claim 2, since the inside of a panel main body is also comprised by the foam layer in the 2nd panel, reduction of the weight of a resin molded product and reduction of the resin material cost are achieved.

  According to the invention of claim 3, since the weld rib is supported from the base end side by the base layer made of a thick solid integrated with the solid layer on the front and back surfaces of the panel body of the second panel, the thin solid Compared to the case where welding ribs are projected from the layer, the base end of the welding rib is peeled off from the back of the panel body of the second panel during vibration welding, or the welding rib is inclined or bent in a direction perpendicular to the vibration direction. Is reliably prevented. Therefore, the first panel and the second panel can be welded and integrated more firmly.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view showing a rear luggage compartment 3 of the automobile 1, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.

  The rear luggage compartment 3 is located behind the rear seat 7 of the automobile 1, and resin trunk side trims 9 are disposed on both sides in the vehicle width direction of the rear luggage compartment 3 so as to cover the vehicle body panel 11. A plate-like floor board 5 as a resin molded product according to Embodiment 1 of the present invention is detachably attached to the rear of the rear cargo room 3 behind the tire house 13. A concave storage portion 15 for storing a tire or the like is formed.

  As shown in FIGS. 3 to 5, the floor board 5 is composed of a resin front panel 17 as a first panel and a resin back panel 19 as a second panel. It is comprised by welding integrated by making it. In FIG. 2, the floor board 5 is simply shown as a cross-sectional view composed of a single panel for the sake of space.

  The front panel 17 is formed integrally with the panel main body 21 that extends substantially flat and forms the main body of the front panel 17 and the peripheral edge 21a of the panel main body 21 over the entire circumference, and projects toward the back panel 19 side. And a substantially rectangular annular peripheral wall portion 23. A recess S <b> 1 is formed inside the peripheral wall portion 23. The panel body 21 of the front panel 17 has a thin solid layer 25 having a high resin density formed on the front and back surfaces and a large number of voids sandwiched between the solid layers 25. And a foam layer 27 having a low resin density. Further, the peripheral edge portion 21 a of the panel body 21 is constituted by a solid layer thicker than the solid layer 25, and the peripheral wall portion 23 is also constituted only by a solid layer thicker than the solid layer 25. In addition, a skin 29 made of a nonwoven fabric or the like is integrally attached to the surface of the panel main body 21 and the peripheral wall portion 23 of the front side panel 17 from the viewpoint of improving the appearance and the vehicle width in the vicinity of the rear side edge of the vehicle body. A holding recess 31 (shown in FIG. 3) is formed in the center of the direction. The vibration direction during vibration welding is indicated by an arrow X in FIG.

  Similar to the front panel 17, the back panel 19 is formed integrally with the panel body 33, which extends substantially flat and forms the main body of the back panel 19, and the peripheral edge 33a of the panel body 33 over the entire circumference. And a peripheral wall portion 35 protruding toward the panel 17 side. A recess S <b> 2 is formed inside the peripheral wall portion 35. The panel body 33 of the back side panel 19 has a thin resin layer 37 having a high resin density and is formed on the front and back surfaces, and a large number of voids inside the solid layer 37. And a foam layer 39 having a low resin density. Further, the peripheral edge portion 33 a of the panel main body 33 is constituted by a solid layer thicker than the solid layer 37, and the peripheral wall portion 35 is constituted only by a solid layer thicker than the solid layer 37. Further, on the back surface of the panel body 33 (the back surface side solid layer 37) of the back side panel 19, five welding ribs 41 made of solid are integrally projected in parallel so as to extend in the vibration direction X. Nearly half of the tips of the welding ribs 41 protrude to the front panel 17 side from the protruding surface 35a of the peripheral wall portion 35. Further, the welding rib 41 is stably supported by a plurality of reinforcing ribs 43 from both sides so as not to bend in a direction orthogonal to the vibration direction X during vibration welding. The reinforcing rib 43 protrudes away from the welding rib 41 in the longitudinal direction.

  The front panel 17 and the back panel 19 are integrated by vibration welding with the recesses S1 and S2 facing each other to constitute the floor board 5. In the floor board 5 assembled in this way, the front end portion of the welding rib 41 penetrates the foam layer 27 through the back surface side solid layer 25 of the panel body 21 of the front panel 17, and the foam layer 27 around the front end portion of the welding rib 41. Is covered with the solid portion 45 melted and solidified and integrated with the foam layer 27 and the solid layer 25 on the back side of the panel body 21 by welding. The panel main bodies 21 and 33 of both the panels 17 and 19 approach each other by the intrusion dimension of the welding rib 41, and the length of the welding rib 41 between the panels 17 and 19, that is, the two panels out of the total length of the welding rib 41. The corresponding length between the back surfaces of 17 and 19 is shortened. Further, the peripheral wall portion 23 of the front side panel 17 and the peripheral wall portion 35 of the back side panel 19 are close to each other to form a gap S3. In addition, the thickness direction side surface 19a of the back side panel 19 is positioned so as to have a width W over the entire circumference inside the thickness direction side surface 17a of the front side panel 17, and the back side panel 19 is a recess S1 of the front side panel 17, that is, the panel The inner part of the rear surface of the main body 21 is covered with respect to the peripheral wall 23.

  Next, a method for manufacturing the floor board 5 configured as described above will be described. First, the front side panel 17 is shape | molded as follows, for example.

  At the time of molding, a mold (not shown), a thermoplastic resin (for example, polypropylene), and a skin 29 are prepared. The forming mold is formed with a first mold as a fixed mold that molds the front side including the peripheral edge portion 21a of the front panel 17, a second mold as a slide mold corresponding to the recess S1, and a protruding end surface 23a of the peripheral wall section 23. And a third mold as a movable mold. The second mold is disposed in the third mold so as to be able to advance and retreat. The thermoplastic resin is a mixture of foaming promoting substances such as a chemical foaming material that generates gas by a chemical reaction and an inert gas (physical foaming material) such as carbon dioxide gas and nitrogen gas. However, it is also possible to use a glass fiber or other fiber mixed therein.

  First, with the skin 29 set on the molding surface of the first mold and the mold closed, the molten thermoplastic resin is injected and filled into the cavity of the mold from the injection machine. At this time, the distance between the first mold and the second mold is preferably set to approximately ½ or more of the thickness of the panel body 21. Thereafter, the thermoplastic resin in the vicinity of the molding surface of the mold begins to solidify early due to the mold temperature, and at this point, the second mold is removed from the first mold while the distance between the first mold and the third mold is fixed. The cavity volume is expanded by separating (sliding) in the mold opening direction. Then, due to the volume expansion of the cavity, the thermoplastic resin that has been compressed between the first mold and the second mold so far (the expansion is restricted) is pulled to the second mold and the chemical reaction in the thermoplastic resin. It expands and expands due to the gas generated by the gas or an inert gas. When fibers such as glass fiber are mixed in the thermoplastic resin, the compression is reduced and the fiber is elastically restored, and the thermoplastic resin is also restored by this elastic restoring force (springback phenomenon). Expands. As a result, the peripheral wall portion 23 and the panel body 21 are molded. The peripheral wall portion 23, the peripheral edge portion 21a of the panel body 21 and the front and back surfaces are formed of solid layers, and a foam layer 27 is formed inside these solid layers.

  The back panel 19 is also formed in the same manner as the front panel 17. The second mold used for forming the back panel 19 is formed with recesses corresponding to the welding ribs 41 and the reinforcing ribs 43. The molten resin filled in the recess is cooled early by the mold temperature of the second mold, and the weld rib 41 and the reinforcing rib are formed even if the second mold is retracted in order to form the foam layer 37. No foam layer is generated in 43, and a solid layer is formed.

  And the front side panel 17 and the back side panel 19 comprised as mentioned above are vibration-welded. At this time, the front panel 17 is set on the lower vibration welding jig so that the back surface faces upward, and the back panel 19 is set on the upper vibration welding jig such that the welding rib 41 faces downward. The peripheral walls 23 and 35 of the front panel 17 and the back panel 19 are opposed to each other, and the side surface 19a of the back panel 19 is positioned so as to have a width W inside the side surface 17a of the front panel 17 so that the front panel The inner side of the peripheral wall 23 on the rear surface of the panel body 21 is covered with the back panel 19 from the back side. From this state, the upper vibration welding jig is pressed against the lower vibration welding jig from above to bring the front end surface of the welding rib 41 of the back side panel 19 into pressure contact with the back surface of the panel body 21 of the front side panel 17. The welding jig is reciprocally vibrated in the longitudinal direction of the floor board 5 (longitudinal direction of the welding rib 41), that is, in the vibration direction X shown in FIG.

  As a result, as shown in FIGS. 4 and 5, the front end portion of the welding rib 41 melts the solid layer 25 by pressure contact vibration with the solid layer 25 on the back surface of the panel body 21 of the front side panel 17, thereby the solid layer 25. And the foam layer 27 around the tip of the weld rib 41 is covered with the solid portion 45 melted and solidified to be integrated with the foam layer 27 and the solid layer 25. In this way, the tip of the welding rib 41 penetrates into the foam layer 27 of the front panel 17 and is welded and integrated with the foam layer 27 as well as the back surface side solid layer 25 of the panel body 21 and is covered with the hard solid portion 45. Therefore, compared with the case where it welds only to the surface of the solid layer 25, a welding area becomes large and high welding strength is obtained. As a result, the wobbling of the welding rib 41 is prevented, and the coupling state of the front side panel 17 and the back side panel 19 is reliably stabilized.

  Therefore, according to the present embodiment, the peripheral wall portions 23 and 35 of the front side panel 17 and the back side panel 19 are not pressed against each other, so that they are not welded to each other, and the welding operation of the welding rib 41 is not hindered.

  In addition, a skin 29 is attached to the surface of the peripheral wall portion 23 of the front side panel 17, but in a state where the welding of the front side panel 17 and the back side panel 19 is finished, the peripheral wall portions 23 and 35 of both the panels 17 and 19 are Since they are close to each other without being welded, it is possible to prevent lint and burrs from being generated on the surface of the skin 29 on the surface of the peripheral wall 23 of the front panel 17 due to friction with the peripheral wall 35 of the back panel 19 during vibration welding. The appearance does not deteriorate.

  Moreover, since the inside of the panel main bodies 21 and 33 of the front side panel 17 and the back side panel 19 is comprised by the foam layers 27 and 39, a weight is reduced compared with the case where the panel main bodies 21 and 33 are comprised only by a solid layer. The

(Embodiment 2)
FIG. 6 shows a floor board 5 according to Embodiment 2 of the present invention. In the second embodiment, a base layer 49 made of a thicker solid than the solid layer 37 formed on the front and back surfaces of the panel main body 33 is provided at the protruding portion of the welding rib 41 of the panel main body 33 of the back panel 19. 33 is formed over the front and back surfaces so as to integrally connect the solid layers 37 on the front and back surfaces, and the foam layer 39 is not formed on the base layer 49. The thickness of the base layer 49 is set to approximately ½ of the thickness of the panel main body 33, and the front side of the base layer 49 (the lower side in FIG. 6) is the front solid layer 37 of the panel main body 33 around the base layer 49. A concave strip 47 is formed along the weld rib 41 on the back side of the base layer 49 (the upper side in FIG. 6, that is, the front panel 17 side). The welding rib 41 and the reinforcing rib 43 are integrally projected on the bottom surface of the base layer 49, that is, the concave portion 47.

  In addition to the first to third molds, the fourth mold corresponding to the concave strip 47 is used for molding the back panel 19 of the second embodiment, and is welded to the fourth mold instead of the second mold. Recesses corresponding to the ribs 41 and the reinforcing ribs 43 are formed. The fourth mold is disposed in the second mold so that the second mold can be advanced and retracted. When the second mold is moved backward to expand and expand the thermoplastic resin, the third mold and the fourth mold are The distance between the first mold and the fourth mold is maintained at the mold-closed state without retreating.

  Therefore, according to the present embodiment, the welding rib 41 and the reinforcing rib 43 are supported from the base end side by the base layer 49 made of a thick solid integrated with the solid layer 37 on the front and back surfaces of the panel body 33 of the back side panel 19. Therefore, as compared with the case where the welding rib 41 is protruded from the thin solid layer 37, the base end portion of the welding rib 41 is peeled off from the back surface of the panel body 33 during vibration welding, or the welding rib 41 is orthogonal to the vibration direction X. It is reliably prevented from tilting or bending in the direction. Therefore, the front side panel 17 and the back side panel 19 can be welded and integrated more firmly.

  In the first and second embodiments, the peripheral wall portions 23 and 35 of the front panel 17 and the back panel 19 are close to each other, but are not welded to each other in a state where the welding of the panels 17 and 19 is completed. You may contact | abut.

  In the first and second embodiments, both the panel body 21 of the front panel 17 and the panel body 33 of the back panel 19 have the foam layers 27 and 39 inside, but the panel body 33 of the back panel 19. May be composed of only a solid layer.

  In the first and second embodiments, the welding rib 41 is provided on the back panel 19. However, the welding rib 41 may be provided on the front panel 17 and the back panel 19 may have the foam layer 39 inside. Good.

  In the first and second embodiments, the skin 29 is provided only on the front panel 17. However, the skin 29 may be provided on the back panel 19 or may not be provided on either of the panels 17 and 19. Good.

  In the first and second embodiments, the case where the resin molded product is the floor board 5 has been described. However, other automotive resin molded products such as a lid of a package tray and a glove box, and further a resin molded product other than an automobile. It can also be applied to.

  INDUSTRIAL APPLICABILITY The present invention is useful as a vibration welded structure of a resin molded product that is integrally welded by vibrating in a state where the first resin panel and the second resin panel are in pressure contact with each other.

It is a perspective view which shows the rear luggage compartment of the motor vehicle with which the floor board as a resin molded product which concerns on Embodiment 1 of this invention was attached. It is sectional drawing in the AA of FIG. It is a top view of a floor board. It is an expanded sectional view in the BB line of FIG. It is the C section enlarged view of FIG. FIG. 6 is a diagram corresponding to FIG. 5 of the second embodiment.

Explanation of symbols

5 Floorboard (resin molded product)
17 Front panel (first panel)
19 Back panel (second panel)
21, 33 Panel body 25, 37 Solid layer 27, 39 Foam layer 41 Welding rib 49 Base layer

Claims (3)

A vibration welded structure of a resin molded product obtained by welding and integrating the resin first panel and the resin second panel while being in pressure contact with each other,
The first panel has a panel body including a thin solid layer formed on the front and back surfaces, and a foam layer sandwiched between the solid layers and having a number of voids inside.
The second panel has a panel body integrally projecting on the back surface so that the welding rib made of solid extends in the vibration direction at the time of vibration welding,
The resin molding characterized in that the weld rib tip portion penetrates the foam layer by breaking through the panel body back side solid layer of the first panel during vibration welding, and is integrated with the foam layer and the solid layer. Vibration welding structure of the product. In the vibration welded structure of the resin molded product according to claim 1,
The panel body of the second panel includes a thin solid layer formed on the front and back surfaces, and a foamed layer sandwiched between the solid layers and having a large number of voids therein. Vibration welding structure. In the vibration welded structure of the resin molded product according to claim 2,
A base layer made of a thicker solid than the solid layer formed on the front and back surfaces of the panel body is integrally formed with the projecting rib projecting portion of the panel body of the second panel. Formed to connect,
A vibration welding structure for a resin molded product, wherein the welding rib is integrally projected on the base layer.

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