Belt molding manufacturing method

Abstract

To provide a manufacturing method of a belt molding capable of preventing or curbing formation of an unnecessary swollen part in a resin-molten part or in the vicinity thereof even in a case of using the resin melting technique by ultrasound oscillation for fixing an end cap to a molding body.SOLUTION: A manufacturing method of a belt molding includes: inserting an end cap 30 into a molding body 10 and arranging an insertion part 32 of the end cap and a facing part 16 of the molding body so that they face each other; melt-deforming a pressed part (16) with an ultrasound horn 40 by pressing the ultrasound horn in an ultrasound oscillation state to the facing part 16 of the molding body and thrusting from an in-vehicle side toward an out-vehicle side and forming a recessed hole part 22 on a pressed surface side of the pressed part and a protruding part 21 protruding to a surface opposite to the pressed surface; then stopping the ultrasound oscillation of the ultrasound horn 40 and further moving the ultrasound horn in an oscillation stop state from the in-vehicle side toward the out-vehicle side; and removing the ultrasound horn from the pressed part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a belt molding for a vehicle, and more particularly to a type of belt molding in which an end cap is attached to one end of a long belt molding body. Such a belt molding can be attached to, for example, a door panel of a front door or a rear door of a vehicle. [Background technology]

[0002] A type of vehicle belt molding is known that has a long molding body that is attached along the edge of a window opening in a door panel and end caps that cover the longitudinal ends of the molding body. In addition, there is a type that uses resin melting based on ultrasonic vibration when fixing the end cap to the molding body, and one example of this is disclosed in Patent Document 1.

[0003] The door waist molding of Patent Document 1 includes a molding body 10 having a design surface 11a, and a fastener 20 (corresponding to an end cap) for fastening the molding body 10 to a door (see Abstract). According to paragraph 0027 and Figures 5 and 8 of the same document, the lower edge 23c of the outer wall 23 of the fastener 20 abuts against the inner surface 11b of the outer wall 11, which is the back side of the design surface 11a of the molding body 10, to form an interface 1a between the resin parts. Then, a welding part 1b consisting of melting parts 11d and 23d is formed at the interface 1a by a welding method such as thermal welding or ultrasonic welding. Paragraph 0028 and Figure 8 of the same document disclose a specific procedure for forming the welding part. That is, as shown in Fig. 8(a), a part of the fixing tool 20 is brought into contact with the inner surface 11b of the molding body 10, and then, as shown in Fig. 8(b), a welding member 40 constituting a heat source or an ultrasonic vibration source is inserted from the outer wall 23 side of the fixing tool 20 until it reaches the vicinity of the interface 1a. Thereafter, the welding member 40 is removed to form the welding part 1b (melted parts 11d, 23d) as shown in Fig. 8(c). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-001551 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology of Patent Document 1 also has the following drawbacks. That is, when the welding member 40 is inserted into the outer wall 23 of the fastener 20 and then removed from the outer wall 23, a hole is formed in the outer wall 23 as a trace of the removal of the welding member. Furthermore, a protruding portion (so-called burr) is also formed on the outer wall 23 on the door outer panel 4 side (i.e., the side opposite the interface 1a) at the periphery of the hole (see FIG. 8(c) in the same document). If the protruding portion is large or the distance between the door outer panel 4 and the outer wall 23 is short, the protruding portion may come into contact with the door outer panel 4 and become an obstacle when the molding is attached to the vehicle. The occurrence of such a situation is undesirable.

[0006] Furthermore, the technology of Patent Document 1 forms the welded portion 1b by thermally welding the inner surface of the molding body 10 and the outer wall 23 of the fixture 20 to each other using a high amount of heat generated by a heat source or an ultrasonic vibration source. For this reason, both the molding body and the fixture (end cap) must be made of resin materials with the same or similar melting points, which is a drawback in that there is little freedom in material selection.

[0007] The main object of the present invention is to provide a manufacturing method for a belt molding which can prevent or suppress the formation of unnecessary protrusions in or near the molten resin portion, even when a method of melting resin using ultrasonic vibration is used to fix an end cap to the molding body. [Means for solving the problem]

[0008] The invention of claim 1 is a method for manufacturing a belt molding to be attached along an upper edge of a door panel of a vehicle door, the belt molding having a long molding body and an end cap attached to one end of the molding body, and at least one of the molding body and the end cap being made of a thermoplastic resin, the method comprising the steps of: preparing a molding body having an exterior side wall portion and an interior side wall portion opposed to each other, and a top wall portion integrally connecting the two side wall portions; preparing an end cap including a lid portion for closing an open end of the molding main body and an insertion portion extending from the lid portion and inserted between an exterior side wall portion and an interior side wall portion of the molding main body; an inserting process for inserting an insert portion of the end cap into the molding body so that the insert portion of the end cap faces a part of the molding body facing the insert portion (hereinafter referred to as an "opposing portion"); an ultrasonic vibration pressing process for pressing an ultrasonic horn in an ultrasonic vibration state against at least one of the opposing portion of the molding main body and the insertion portion of the end cap, and pushing the ultrasonic horn from the inside of the vehicle toward the outside of the vehicle, thereby melting and deforming the portion pressed by the ultrasonic horn, and forming a recessed hole portion on the pressed surface side of the pressed portion and a protruding portion on the surface opposite to the pressed surface; a non-vibration pressing step of stopping the ultrasonic vibration of the ultrasonic horn and further moving the ultrasonic horn in a vibration-stopped state from the vehicle inner side toward the vehicle outer side at the pressing portion; a removal step of removing the ultrasonic horn from the pressed portion; Equipped with The end cap is fixed to the molding body by engagement between the molding body and the end cap via a protrusion formed at the pressing portion, and the movement of the end cap in the direction opposite to the insertion direction in the insertion step is restricted. The present invention relates to a method for manufacturing a belt molding.

[0009] According to the invention of claim 1, after the opposing portion of the molding body and the insertion portion of the end cap are arranged opposite to each other, the ultrasonic horn in an ultrasonic vibration state is pressed and pushed against at least one of these portions, thereby melting and deforming the pressed portion by the ultrasonic horn, and a hole portion and a protrusion portion can be formed at the pressed portion at the same time (note that the protrusion portion is involved in fixing the end cap to the molding body). At that time, as the ultrasonic horn in an ultrasonic vibration state is pushed in, a protrusion portion may be generated around the hole portion formed at the same time as the protrusion portion due to the molten resin overflowing from the hole portion in search of an escape route. If this protrusion portion is left and solidifies, it will become a burr. However, in the present invention, in the non-vibration pressing process following the ultrasonic vibration pressing process, the vibration of the ultrasonic horn is stopped to promote the solidification (i.e., the fluidity is reduced) of the molten resin, and the ultrasonic horn in a vibration-stopped state is further moved from the inside of the vehicle to the outside of the vehicle, so that the molten resin protruding around the hole portion can be gradually solidified while being drawn into the inside of the hole portion. Therefore, according to the present invention, even when a protrusion is formed using a method of melting resin using ultrasonic vibration to fix an end cap to a molding body, it is possible to prevent or suppress the formation of unnecessary protrusions in or near the hole formed at the same time as the protrusion.

[0010] The invention of claim 2 is a manufacturing method of the belt molding according to claim 1, a hook surface is formed on the insertion portion of the end cap so as to intersect with an insertion direction of the end cap, and the opposing portion of the molding body is located on the vehicle inner side of the insertion portion of the end cap, The ultrasonic vibration pressing process is characterized in that the opposing portion of the molding main body, which is closer to the lid portion of the end cap than the hook surface, is melted and deformed to form the protrusion on the molding main body that protrudes from the inside of the vehicle to the outside of the vehicle.

[0011] According to the invention of claim 2, in addition to the effects of the invention of claim 1, the following effects are further achieved. That is, by melting and deforming a portion of the opposing portion of the mall body closer to the lid portion of the end cap than the engaging surface to form a protruding portion, the movement of the end cap in the direction opposite to the insertion direction is blocked based on the engagement (mechanical engagement) between the protruding portion and the engaging surface of the end cap insertion portion, and it is possible to prevent the end cap from falling off the mall body. Note that since this method does not weld the mall body and the end cap, it is not necessary to form the mall body and the end cap from materials with similar melting points, and there are fewer restrictions on material selection.

[0012] The invention of claim 3 is characterized in that, in the method for manufacturing a belt mall according to claim 1 or 2, the pushing-in movement amount (X) of the ultrasonic horn in the ultrasonic vibration pressing step is larger than the movement amount (Y) of the ultrasonic horn in the non-vibration pressing step.

[0013] According to the invention of claim 3, in addition to the effects of the inventions of claims 1 and 2, the following effects are further achieved. That is, by setting the pushing-in movement amount (X) of the ultrasonic horn in the ultrasonic vibration state to be larger than the movement amount (Y) of the ultrasonic horn in the vibration-stopped state (Y < X), it is possible to ensure that the protruding amount of the protruding portion is sufficiently large.

[0014] The invention of claim 4 is characterized in that, in the method for manufacturing a belt mall according to any one of claims 1 to 3, the ultrasonic horn has a tip convex portion formed at its tip, an annular concave portion formed on the outer periphery of the tip convex portion, and an annular ridge formed on the outer peripheral edge of the annular concave portion.

[0015] According to the invention of claim 4, in addition to the effects of the inventions of claims 1 to 3, the following effects are further achieved. That is, according to the above ultrasonic horn, in the ultrasonic vibration pressing step and the non-vibration pressing step, the ultrasonic horn can be stably pushed toward at least one of the opposing portion of the mall body and the insertion portion of the end cap. Also, compared to the case where the ultrasonic horn does not have an annular concave portion, the resistance received by the ultrasonic horn from the molten resin can be reduced.

[0016] The invention of claim 5 is the method for manufacturing a belt molding according to claim 4, characterized in that in the ultrasonic vibration pressing step, a tip protrusion of an ultrasonic horn is ultrasonically vibrated.

[0017] According to the invention of claim 5, in addition to the effect of the invention of claim 4, the following effect is further achieved. That is, by vibrating only the tip convex part of the ultrasonic horn instead of vibrating the entire ultrasonic horn including the annular recess, the amount of resin to be melted can be suppressed, and part of the molten resin can be received in the annular recess, so that the amount of excess molten resin that overflows and protrudes around the hole can be reduced. Effect of the Invention

[0018] As described above in detail, according to the present invention, even when a protrusion is formed using a method of melting resin using ultrasonic vibration to fix an end cap to a molding body, it is possible to prevent or suppress the formation of unnecessary protrusions in or near the hole formed at the same time as the protrusion. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic diagram of a vehicle door (front door). [Diagram 2] A cross-sectional view of the belt molding taken along line II-II in Figure 1. [Diagram 3] 3 is a rear side view of a belt molding (encircled portion III in FIG. 1) according to one embodiment; FIG. [Figure 4] An exploded view (rear side view) of the belt molding shown in Figure 3. [Diagram 5] 4A shows a cross section taken along line VV in FIG. 3, and FIG. 4B is a partially enlarged cross-sectional view showing a part of A in an enlarged manner. [Figure 6] 6A and 6B are schematic cross-sectional views showing a cross section taken along line VI-VI in FIG. 3, in which (A) and (B) are schematic cross-sectional views showing a series of steps for forming a protrusion. [Figure 7]6A and 6B are cross-sectional views taken along line VI-VI in FIG. 3, in which (C) and (D) are schematic cross-sectional views showing a series of steps for forming a protrusion. [Figure 8] FIG. 11 is a schematic cross-sectional view showing another example of the ultrasonic horn. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] Fig. 1 shows a typical example of use of the belt molding according to the present invention. As shown in Fig. 1, a belt molding 3 is attached along the upper edge (belt line) of an outer door panel 2 constituting the lower half of a vehicle door 1. The belt molding 3 has a long belt molding main body (hereinafter referred to as "molding main body") 10 and an end cap 30 attached to the rear end of the molding main body 10 (the right end as viewed in Fig. 1).

[0022] As shown in FIG. 2, the molding body 10 has an exterior side wall portion 11 and an interior side wall portion 12 that face each other, and a top wall portion 13 that integrally connects these two side walls 11, 12. The three walls (11-13) form the molding body 10 into a generally U-shaped cross section that opens downward. The lower end of the exterior side wall portion 11 is provided with a folded protrusion 14 that is folded back toward the interior side of the vehicle. An interior lip 15a is provided on the interior side surface of the interior side wall portion 12, an exterior lip 15b is provided near the lower end of the exterior side wall portion 11, a retaining lip 15c is provided at the tip of the folded protrusion 14 at the lower end of the exterior side wall portion, and a decorative lip 15d is provided near the joint between the top wall portion 13 and the interior side wall portion 12. However, these lips 15a-d are generally known. In addition, by inserting the flange 2f (shown in phantom lines) of the door panel 2 into the lower opening of the belt molding 3, the flange 2f is clamped between the retaining lip 15c and the interior side wall portion 12, and the belt molding 3 is attached to the door panel 2.

[0023] The molding body 10 is preferably formed by extrusion molding of an olefin-based thermoplastic resin material. However, the three walls (11-13) and the ridges (14) of the molding body 10 are made of a relatively hard olefin-based thermoplastic resin (e.g., polypropylene). On the other hand, the four lips (15a-d) other than the three walls and the ridges are made of a relatively soft olefin-based thermoplastic elastomer. The molding body 10 may be made of any material that is meltable and elastically deformable, and may be made of any material other than the olefin-based thermoplastic resin (e.g., styrene-based thermoplastic resin, polyvinyl chloride, rubber, etc.).

[0024] The end cap 30 is preferably made of polybutylene terephthalate (PBT), which is a type of thermoplastic resin. In addition to PBT, examples of thermoplastic resins that can be used for the end cap 30 include acrylonitrile butadiene styrene (ABS) resin, polypropylene (PP), polyacetal (POM), polyamide (PA), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK).

[0025] 3 to 7 show the main features of the belt molding of this embodiment. FIG. 3 shows an assembled state of the belt molding near the end cap 30, and FIG. 4 shows a disassembled state of the molding main body 10 and the end cap 30. As shown in FIG. 4, near the rear end of the molding main body 10, mainly the lower part of the interior side wall portion 12 is removed, and the upper part of the interior side wall portion 12 remains (hereinafter, this remaining part is referred to as the "side wall remaining part 16"). Incidentally, the side wall remaining part 16 does not have the interior lip 15a, and with the formation of the side wall remaining part 16, the retaining lip 15c of the exterior side wall portion 11 at the part facing the side wall remaining part 16 is also mostly cut away, leaving only the root part. An internal space for inserting and arranging the insertion part 32 of the end cap 30 is partitioned by three wall parts (the exterior side wall portion 11, the top wall part 13, and the side wall remaining part 16) located near the rear end of the molding main body 10.

[0026] As shown in Figures 3 and 4, a protruding portion 17 is formed at the end of the molding main body 10 by a part of the side wall remainder 16. The protruding portion 17 is a side wall portion that protrudes downward from the upper edge of the vehicle interior side wall portion 12 and forms a part of the side wall remainder 16. This protruding portion 17 is somewhat elastically deformable toward the vehicle interior side when the end cap 30 is attached to the molding main body 10. The protruding portion 17 has a front edge 17a and a rear edge 17b, and the front edge 17a is formed with a locked portion 18 that extends in a direction intersecting with the insertion direction of the end cap. The rear edge 17b of the protruding portion 17 forms the rear end (open end) of the molding main body 10.

[0027] 3 and 4, the end cap 30 has a lid portion 31 and an insertion portion 32 extending substantially horizontally from the front surface of the lid portion 31 along the longitudinal direction (i.e., the insertion direction) of the end cap. The lid portion 31 is a portion for closing the rear end (open end) of the molding main body 10, and constitutes the rearmost end portion of the end cap 30. The insertion portion 32 is a portion that is inserted between the exterior side wall portion 11 and the remaining side wall portion 16 of the molding main body 10. The insertion portion 32 has an interior side surface 32a that extends along the insertion direction of the end cap on the interior side of the vehicle.

[0028] The insertion portion 32 of the end cap is provided with a thick plate-shaped support portion (hereinafter referred to as a "support tab") 33 formed to extend downward from the upper edge of the insertion portion 32. The support tab 33 is a part of the insertion portion 32 of the end cap. The support tab 33 is substantially rectangular in side view, and a locking portion 34 is provided at a front position of the support tab 33, which protrudes toward the inside of the vehicle from an interior side surface 33a of the support tab 33. The locking portion 34 functions as a means for provisionally positioning (or provisionally fixing) the end cap 30 to the molding main body 10 based on mutual locking with the locked portion 18 of the protruding portion 17 when the end cap 30 is inserted into the molding main body 10. As shown in FIG. 4, the locking portion 34 of the support tab 33 has an inclined surface 35 formed at its front position. This inclined surface 35 functions as a pressing and guiding surface for pressing the projection 17 of the molding body toward the inside of the vehicle when the end cap 30 is inserted into the molding body 10, thereby guiding temporary elastic deformation.

[0029] Furthermore, the end cap 30 has a hook portion 37 formed on the upper side of the insertion portion 32 at a position forward of the support tab 33. The hook portion 37 is a recess formed by cutting out a substantially semicircular shape when viewed from the side in FIG. 4, and this semicircular shape corresponds to the outer shape (circular shape) of the tip of the ultrasonic horn 40 described later. It is preferable that the radius of the semicircular shape of the hook portion 37 is set to be slightly larger than the radius of the circular shape of the ultrasonic horn. This can prevent the resin melted from the side wall remaining portion 16 described later from overflowing around the semicircular shape of the hook portion 37. The hook portion 37 has a curved hook surface 37a on the inside of the concave shape, which is expanded in the vehicle interior / exterior direction (width direction of the end cap) (see FIGS. 4 and 5). This hook surface 37a is in a positional relationship that intersects with the vehicle interior side surface 32a of the end cap insertion portion 32, and acts to prevent the end cap from moving (i.e., moving in the opposite direction to the insertion direction of the end cap) based on engagement with the protrusion 21 described later.

[0030] 4 and 5, the hook portion 37 is depicted as a recess penetrating the insertion portion 32 in the vehicle interior / exterior direction (width direction of the end cap), but the hook portion 37 as a recess does not need to penetrate the insertion portion 32 and may be a recess of a non-penetrating form in which the vehicle interior side surface 32a of the insertion portion 32 is simply recessed toward the vehicle exterior. In short, the form of the hook portion 37 (penetrating / non-penetrating) is not important as long as the hook surface 37a as described above can be provided.

[0031] Next, a method for attaching and fixing the end cap 30 to the molding main body 10 (i.e., a method for assembling a belt molding) will be described. This method generally includes an insertion process for inserting and arranging the end cap 30 into the molding main body 10 after preparing the molding main body 10 and the end cap 30 as described above in advance, and a series of processes for forming a protrusion 21, which will be described later, on the molding main body 10 in order to fix the end cap 30 to the molding main body 10 (this series of processes is collectively referred to as a "protrusion forming process").

[0032] In the insertion process, the insertion portion 32 of the end cap 30 is inserted into the molding body 10 from the opening end of the molding body. Then, first, the inclined surface 35 located in front of the locking portion 34 of the end cap abuts against the rear edge 17b of the overhanging portion 17 of the molding body. As the end cap 30 is further pushed in, the rear edge 17b of the overhanging portion slides along the inclined surface 35, and the overhanging portion 17 is gradually elastically deformed toward the inside of the vehicle by the pressing and guiding action of the inclined surface 35. After that, when the end cap 30 is further pushed in and the locking portion 34 of the end cap passes the position of the overhanging portion 17, the contact sliding between the overhanging portion 17 and the locking portion 34 is released, and the overhanging portion 17, which was temporarily elastically deformed, returns to its original position or shape before deformation. Almost in synchronization with the return of the overhanging portion 17 from the elastically deformed state, the lid portion 31 of the end cap abuts against the opening end of the molding body 10. This contact prevents the end cap 30 from moving forward any further, completing the insertion of the end cap 30 into the molding body 10 (see Figs. 3 and 4).

[0033] In the fully inserted state, as shown in Fig. 3, the locking portion 34 of the end cap 30 is disposed in front of the locked portion 18 of the protruding portion 17 of the molding main body. Therefore, even if an external force is applied to the end cap 30 in the pull-out direction (i.e., the direction opposite to the end cap insertion direction), the locking portion 34 will catch on the locked portion 18, and the end cap 30 will not come out of the molding main body 10. In this way, the end cap 30 is provisionally positioned relative to the molding main body 10 based on the mutual locking between the locking portion 34 and the locked portion 18. This serves as a prerequisite or preliminary step for smoothly executing the subsequent protrusion forming process.

[0034] In addition, in the fully inserted state, as shown in Fig. 6(A) and Fig. 5(A), the upper edge portion (particularly the vicinity of the hook portion 37) of the insertion portion 32 of the end cap 30 and the side wall remainder 16 of the molding main body 10 are disposed to face each other. That is, in this embodiment, the side wall remainder 16 is "the opposing portion that is located on the vehicle inner side of the insertion portion (32) of the end cap and faces the insertion portion (32)." Incidentally, as can be seen from Fig. 5(A), the insertion portion 32 and the side wall remainder 16 as the opposing portion face each other substantially in parallel, so that a gap S is inevitably formed between the two portions.

[0035] In the protrusion forming process following the insertion step, a protrusion 21 that protrudes outside the vehicle beyond the interior side surface 32a of the insertion portion 32 of the end cap is formed in the molding main body 10 by deforming (melting and deforming) the portion of the side wall remainder 16 serving as the opposing portion, which is closer to the lid portion 31 than the hook surface 37a of the end cap.

[0036] In the protrusion forming process, an ultrasonic horn 40 as shown partially and diagrammatically in FIG. 6(A) is used as the melting and deforming means. The ultrasonic horn 40 used in this example has a tip end projection 41 having a circular cross section and an annular ridge 42 surrounding the tip end projection 41. An annular recess 43 is formed between the tip end projection 41 and the annular ridge 42 along the outer periphery of the tip end projection 41. The annular recess 43 receives a part of the resin melted by the tip end projection 41. In forming the protrusion, the ultrasonic horn 40 is disposed on the vehicle inner side of the molding main body 10, and the rear side surface of the lid portion 31 of the end cap 30 is placed against a jig (not shown) to position the end cap 30 and the molding main body 10.

[0037] 6(A), (B) and 7(C), (D) show specific steps of the protrusion forming process for forming the protrusion 21 on the molding body 10. This protrusion forming process is composed of a series of steps including an ultrasonic vibration pressing step, a non-vibration pressing step, and a removal step.

[0038] In the ultrasonic vibration pressing process shown in Fig. 6(A) and (B), first, the ultrasonic horn 40 is disposed facing the side wall remainder 16 and the insertion portion 32 so that the tip protrusion 41 of the ultrasonic horn 40 faces the hook portion 37 of the end cap 30 with the side wall remainder 16 of the molding body sandwiched therebetween (see Fig. 6(A)). Then, the tip protrusion 41 of the ultrasonic horn 40 is pressed against the side wall remainder 16 at a substantially right angle, and then the tip protrusion 41 of the ultrasonic horn 40 is ultrasonically vibrated and slowly pushed toward the hook portion 37 (i.e., moved forward while being pressed). As the ultrasonic horn 40 is pushed in the ultrasonic vibration state, a part of the side wall remainder 16 is pinpoint heated and melted, and the molten resin is pushed by the tip protrusion 41 of the ultrasonic horn and enters the hook portion 37, so that at least the protrusion 21 and the central hole 22 are simultaneously formed in the side wall remainder 16 (see Fig. 6(B)). At that time, as shown in Fig. 6(B), the molten resin occupying the inside of the hole 22 overflows from the periphery of the hole 22 in search of an escape route, and part of the molten resin enters the annular recess 43 of the ultrasonic horn, while the excess of the molten resin that cannot be contained in the annular recess 43 climbs over the annular protrusion 42 and rises outward from around the hole 22. In this way, an annular protrusion R is temporarily formed by the leaked molten resin so as to protrude along the outer circumferential surface of the ultrasonic horn 40 from the pressing surface of the side wall remainder 16, which is the pressing portion of the ultrasonic horn 40. Note that the amount by which the ultrasonic horn 40 in the ultrasonic vibration state is pushed from the inside of the vehicle toward the outside of the vehicle (push-in movement amount X) after the tip protrusion 41 of the ultrasonic horn 40 is brought into contact with the pressing surface of the side wall remainder 16 is, for example, 4.0 mm.

[0039] Subsequent to the ultrasonic vibration pressing step, in the non-vibration pressing step shown in Fig. 7(C), the ultrasonic vibration of the tip projection 41 of the ultrasonic horn 40 is stopped, and the ultrasonic horn 40 in the vibration-stopped state is further pushed from the vehicle interior side toward the vehicle exterior side. When the heat supply to the molten resin is cut off due to the stop of the vibration of the ultrasonic horn 40, the solidification of the molten resin or the reduction of its fluidity is promoted by natural cooling. Under this situation, by further moving the ultrasonic horn 40 in the vibration-stopped state toward the vehicle exterior side, the molten resin that forms the temporarily generated ridge R around the hole 22 is drawn into the hole 22 and gradually loses its fluidity and solidifies. As a result, the temporarily generated ridge R almost disappears at the end stage of the non-vibration pressing step or becomes so small that it cannot be visually confirmed, preventing or suppressing the generation of so-called burrs.

[0040] In this embodiment, the amount (movement amount Y) by which the ultrasonic horn 40 in the vibration-stopped state is further moved from the vehicle interior side toward the vehicle exterior side after the vibration of the ultrasonic horn 40 is stopped is, for example, 0.04 mm. By setting the pushing movement amount X of the ultrasonic horn 40 in the ultrasonic vibration state to be larger than the movement amount Y of the ultrasonic horn 40 in the vibration-stopped state (Y < X), it is possible to ensure that the protruding amount of the protruding portion 21 toward the vehicle exterior side is sufficiently large.

[0041] Note that the amount by which the ultrasonic horn 40 in the vibration-stopped state is moved in the non-vibration pressing step may be controlled (or managed) by the movement amount Y or may be controlled (or managed) by time. For example, when controlling by time, it is preferable to apply a predetermined force to the ultrasonic horn and set the total time of the ultrasonic vibration pressing step and the non-vibration pressing step to 2 seconds. By such movement control (or movement amount management), the reproducibility of the protruding portion 21 and the hole 22 (and its vicinity) formed simultaneously based on the melting deformation is enhanced, and the quality of the belt mold can be stabilized.

[0042] After the non-vibration pressing step, as shown in Fig. 7(D), the ultrasonic horn 40 is removed from the side wall remainder 16 (removal step). That is, the ultrasonic horn 40, which is in a vibration-stopped state, is moved backward in a direction (backward direction) opposite to the direction of pushing or pressing (forward direction) in the ultrasonic vibration pressing step and the non-vibration pressing step, and the ultrasonic horn 40 is pulled away from the side wall remainder 16. Then, the protrusion 21, which was solidifying, is completely solidified within the hook portion 37 by further natural cooling, and the solid protrusion 21 is completed.

[0043] 5(B) and 7(D), complementary shapes (i.e., central hole 22, annular protrusion 23, annular groove 24) are formed on the back side (base end side) of protrusion 21 after removal of ultrasonic horn 40 as removal marks reflecting tip protrusion 41, annular recess 43, and annular ridge 42 of ultrasonic horn 40. Note that, with respect to protrusion 21 protruding from one surface of sidewall remainder 16 as the portion pressed by the ultrasonic horn, hole 22 is positioned as a recessed portion on the side of the pressing surface of sidewall remainder 16 (pressing portion).

[0044] 5(B), the protrusion R that was temporarily generated on the pressed surface of the side wall remaining portion 16 has almost disappeared when the protrusion forming process is completed, and so-called burrs are not present on the pressed surface. As described above, according to this embodiment, since no burrs are generated around the hole portion 22, when the belt molding is attached to the door panel, it is possible to arrange another part on the vehicle interior side of the belt molding without the burrs getting in the way.

[0045] 5(A) and 7(D), the completed protrusion 21 is disposed within the hook portion 37 of the end cap, and is disposed adjacent to the hook surface 37a in the longitudinal direction of the belt molding, and abuts against the hook surface 37a. The mutual abutment of the protrusion 21 on the molding main body side and the hook surface 37a on the end cap side fixes the molding main body 10 and the end cap 30 to each other, preventing or suppressing rattling between them.

[0046] Incidentally, as part of the side wall remainder 16 is melted by the ultrasonic horn 40 during the process of forming the protrusion, as shown in an enlarged view in FIG. 5(B), a small part (19) of the molten thermoplastic resin leaks out around the protrusion 21 and enters and fills the gap S between the insertion portion 32 and the side wall remainder 16. However, since the gap S is very narrow, the molten resin (19) does not immediately flow out of the gap S, but can remain in the gap S moderately due to the surface tension of the molten resin, etc. The resin layer 19 that fills the gap S solidifies over time while being integrated with the protrusion 21, and the resin layer 19 solidified in the gap S helps to prevent or suppress rattling between the molding main body 10 and the end cap 30.

[0047] 5 to 7, the length and diameter of the tip convex portion 41 of the ultrasonic horn 40 can be appropriately selected. In this embodiment, the length of the tip convex portion 41 is set (selected) so that the tip convex portion 41 of the ultrasonic horn 40 can abut against the rear surface of the vehicle exterior side wall portion 11 in the ultrasonic vibration pressing process and the non-vibration pressing process, but the tip convex portion 41 does not need to be so long that the tip convex portion 41 abuts against the rear surface of the vehicle exterior side wall portion 11, and may be made a little shorter.

[0048] [Effects of the embodiment] According to this embodiment, the protrusion 21 and the hole 22 can be simultaneously formed in the remaining side wall 16 (the portion pressed by the ultrasonic horn 40) of the molding main body through the protrusion forming process as described above. In particular, in the non-vibration pressing process following the ultrasonic vibration pressing process, the vibration of the ultrasonic horn 40 is stopped to promote solidification of the molten resin (i.e., reduction in fluidity), and the ultrasonic horn 40 in the vibration-stopped state is further moved from the inside of the vehicle to the outside of the vehicle, so that the molten resin protruding around the hole 22 can be gradually solidified while being drawn into the inside of the hole 22. Thus, it is possible to prevent or suppress the formation of an unnecessary protrusion R in or near the hole 22 formed simultaneously with the protrusion 21.

[0049] According to this embodiment, the protruding portion 21 formed by melting and deforming a part of the side wall remaining portion 16 as the opposing portion protrudes toward the outside of the vehicle beyond the inside surface 32a of the end cap insertion portion 32, and the movement of the end cap 30 in the direction opposite to the insertion direction is restricted based on the engagement between the protruding portion 21 and the hook surface 37a of the end cap insertion portion 32. This makes it possible to prevent the end cap 30 from falling off from the molding main body 10.

[0050] In the method of this embodiment, the molding body 10 and the end cap 30 are not welded to each other, so there is no need to form the molding body 10 and the end cap 30 from materials with similar melting points, and there are fewer restrictions on material selection. Also, in the protrusion formation process, the molding body 10 is melted and deformed, so there is no need to deform the end cap 30, and therefore there is no risk of the end cap 30 cracking even if it is made of a material that cracks easily (for example, PBT resin).

[0051] By using the ultrasonic horn 40 having the annular protrusion 42 and annular recess 43 as shown in Fig. 6(A), the tip protrusion 41 can be stably pressed against the remaining side wall 16 of the molding body 10 in the ultrasonic vibration pressing process and the non-vibration pressing process, and the resistance that the ultrasonic horn 40 receives from the molten resin can be reduced compared to when the annular recess 43 is not formed. In addition, the amount of molten resin can be reduced by ultrasonically vibrating the tip protrusion 41 to melt the resin part that the tip protrusion 41 contacts, and by receiving and retaining a part of the excess molten resin in the annular recess 43, the amount of molten resin that overflows and protrudes around the hole 22 can be reduced, and the occurrence of the protrusion R can be prevented or suppressed.

[0052] [Modifications] The present invention is not limited to the above-described embodiment, and can be implemented in the following aspects. For example, in the above embodiment, the ultrasonic horn 40 in an ultrasonically vibrated state was pressed against the opposing portion (side wall remaining portion 16) of the molding main body 10 to melt the opposing portion of the molding main body, but the insertion portion 32 of the end cap 30 may also be melted by the ultrasonic horn 40.

[0053] In the above embodiment, an ultrasonic horn 40 was used in which an annular recess 43 and an annular ridge 42 were formed on the outer periphery of the tip protrusion 41 of the ultrasonic horn. However, instead of this, as shown in FIG. 8, an ultrasonic horn 40A may be used in which neither annular recess 43 nor annular ridge 42 is formed on the outer periphery of the tip protrusion 41, and only an annular flat step portion 45 is formed.

[0054] In the above embodiment, the protruding portion 21 is formed at only one location, but the protruding portion 21 may be formed at two or more locations to firmly fix the end cap 30 to the molding main body 10. [Explanation of symbols]

[0055] 1 Vehicle door 2 Door Panel 3 Belt Molding 10. Mall body 11 Vehicle exterior side wall 12 Car interior side wall 13 Top wall 16 Remaining side wall (opposing part, pressed part by ultrasonic horn) 17 Overhang 18 Locked part 21 Protrusion 22 Center hole 30 End Cap 31 Lid 32 Insertion section 32a Insertion part inside the car 37 Hook section 37a Hook surface 40,40A Ultrasonic Horn 41 Tip convex part 42 Annular ridge 43 Annular recess

Claims

1. A method for manufacturing a belt molding to be attached along an upper edge of a door panel of a vehicle door, the belt molding having a long molding body and an end cap attached to one end of the molding body, and at least one of the molding body and the end cap being made of a thermoplastic resin, the method comprising the steps of: preparing a molding body having an exterior side wall portion and an interior side wall portion opposed to each other, and a top wall portion integrally connecting the two side wall portions; preparing an end cap including a lid portion for closing an open end of the molding main body and an insertion portion extending from the lid portion and inserted between an exterior side wall portion and an interior side wall portion of the molding main body; an inserting process for inserting an insert portion of the end cap into the molding main body so that the insert portion of the end cap faces a part of the molding main body facing the insert portion (hereinafter referred to as an "opposing portion"); an ultrasonic vibration pressing process for pressing an ultrasonic horn in an ultrasonic vibration state against at least one of the opposing portion of the molding main body and the insertion portion of the end cap, and pushing the ultrasonic horn from the inside of the vehicle toward the outside of the vehicle, thereby melting and deforming the portion pressed by the ultrasonic horn, and forming a recessed hole portion on the pressed surface side of the pressed portion and a protruding portion on the surface opposite to the pressed surface; a non-vibration pressing step of stopping the ultrasonic vibration of the ultrasonic horn and further moving the ultrasonic horn in a vibration-stopped state from the vehicle inner side toward the vehicle outer side at the pressing portion; a removal step of removing the ultrasonic horn from the pressed portion; a protrusion formed at the pressing portion, the protrusion engaging the molding body with the end cap, and based on this engagement, movement of the end cap in a direction opposite to an insertion direction in the insertion step is restricted, and the end cap is fixed to the molding body.

2. a hook surface is formed on the insertion portion of the end cap so as to intersect with an insertion direction of the end cap, and the opposing portion of the molding body is located on the vehicle inner side of the insertion portion of the end cap, In the ultrasonic vibration pressing process, a portion of the facing portion of the molding main body that is closer to the lid portion of the end cap than the hook surface is melted and deformed to form the protruding portion that protrudes from the vehicle inner side to the vehicle outer side of the molding main body. The method for manufacturing a belt molding according to claim 1 .

3. 3. The method for manufacturing a belt molding according to claim 1, wherein a pressing movement amount (X) of the ultrasonic horn in the ultrasonic vibration pressing step is greater than a movement amount (Y) of the ultrasonic horn in the non-vibration pressing step.

4. The method for manufacturing a belt molding according to any one of claims 1 to 3, characterized in that the ultrasonic horn has a tip convex portion formed at its tip, an annular recess portion formed on the outer periphery of the tip convex portion, and an annular ridge portion formed on the outer periphery of the annular recess portion.

5. 5. The method for manufacturing a belt molding according to claim 4, wherein in the ultrasonic vibration pressing step, a tip protrusion of an ultrasonic horn is ultrasonically vibrated.

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