JPH0585621U - Bonding structure of resin molded parts - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide a joint structure for resin molded parts, which can eliminate the entry of air into the joints of a plurality of resin molded parts and easily finish the appearance of the joint parts beautifully. [Structure] A joint structure of resin molded parts in which end portions of a plurality of resin molded parts 1, 11 are fused and integrated with a molten resin with substantially the same thickness, and the resin molded parts 1, 11 should be connected. The joints 1 and 11 which are thinner than the thickness in the vicinity thereof are provided at the respective end portions, and the joints 1 and 11 are formed with the projections 5 having the same or almost the same height as the thickness of the resin molded part. The spaces were fused with a molten resin to have almost the same thickness and integrated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a method for joining resin molded parts and a joining apparatus therefor, and more specifically, a method and an apparatus for manufacturing a desired resin molded article by welding a plurality of resin molded parts to integrate them. It is about.

[0002]

[Prior art]

 Conventionally, as a method of manufacturing a resin molded product, a method of integrally molding a target product to obtain a target product (hereinafter referred to as an integral molding method) and a plurality of parts separately There is a method (hereinafter, referred to as a split-type molding method) of forming a desired product by molding and fusing these molded parts together by welding.

The above-mentioned integral molding method is intended to manufacture a mold capable of accommodating a product capable of integrally manufacturing the entire product, and inject a molten resin into the mold. Manufacture the product. The product produced by this method has no joints and has a beautiful appearance.

However, since the entire product is integrally molded, when the product is large, the die becomes very large, and as a result, the entire molding apparatus becomes large. Further, in this case, a large space for installing the device is required.

Further, technically, it is difficult for a large-sized mold to provide high precision over a wide molding surface, and furthermore, an upper mold and a lower mold which are fitted and integrated during molding. In the case of a product having a complicated shape, it is sometimes very difficult to form the divided part and the divided shape due to the manufacturing technique, and it may be very difficult to manufacture the mold. Further, even in the case of a manufacturable shape, enormous cost is required for manufacturing a device including a mold and the like for the reason described above.

On the other hand, in the split mold forming method, as described above, the entire product is integrally formed by welding a plurality of separate molded parts between respective end portions to be connected to each other. .. For this reason, the joint appears in the appearance. However, on the other hand, there is an advantage that it is not necessary to manufacture a large mold capable of accommodating the entire product, and thus a large molding device is not required. Also, in this method, if there is a welding device for welding the joints, the entire molding is possible, so the molding device for molding each molded part and the mold of each part can be relatively small. It also has the advantage of low manufacturing cost.

As described above, each of the above two molding methods has its own characteristics. Generally, the integral molding method is used for manufacturing a relatively small product or a product having a relatively simple shape. The split-type molding method is used when manufacturing a product having a relatively large size and a complicated shape.

By the way, as one of the products manufactured by resin molding, there is a cowling for a motorcycle. In recent years, the cowling covers from the upper part of the handle to the lower part of the engine in view of reduction of air resistance and aesthetics. Many of them are large in size, and the shape is complicated to reduce air resistance as much as possible.

As described above, the above-mentioned split-type molding method is used for manufacturing the large-sized and complicated-shaped cowling for the above-mentioned reason.

The main welding method of the cowling of the motorcycle used in the current split-type molding method is the first method shown in FIGS. 11 and 12, and the welding method shown in FIGS. 13 and 14. There is a second method.

As shown in FIGS. 11 and 12, the first welding method attempts to connect the end portions of the two molded parts 51 and 61, one from the outer surface side and the other from the inner surface side. Formed are joints 52 and 62 each having a half-thickness projecting in the direction of the parts. With these joints 52 and 62 joined together, the ultrasonic welding machine is applied to multiple points of the joined parts. By welding (the welded portion is indicated by a cross in the figure) to integrate them.

The second welding method is, as shown in FIG. 13 and FIG. 14, joining the joints 52, 62 of two molded parts 51, 61 in a state of abutting each other, and the inner surface is joined to the joined portion. The reinforcing plate 55 is brought into close contact (so-called backing) from the (back surface), and the overlapped portions (overlapping portions) 56 and 66 are welded by an ultrasonic welding machine (mark the welded portion with a cross in the figure). It is to be integrated).

In all of the conventional welding methods as described above, so-called spot welding is performed by an ultrasonic welding machine on the overlapping portion with the end faces of the two joints abutting each other on the outer surface side of the joint. It is a thing.

For this reason, a gap (referred to as a concave portion; for example, a concave portion 54) is formed on the outer surfaces of the joint portions of the two joint portions. Therefore, after welding, the concave part (54) formed on the outer surface of the joint is filled with an adhesive to close the gap, and after drying, the adhesive that protrudes from the outer surface of the joint and solidifies is scraped off and polished to smooth the surface. Is finished.

After that, the cowling in which the above-mentioned joints are finished and integrated is sent to a coating process, and a desired coating color is applied to form a final product (component; cowling).

As a prior art of this kind, “a method for manufacturing a fairing” for preventing reduction of strength of a divided portion in a welded portion of a molded part and preventing a deviation or a step from occurring in this portion (Japanese Patent Publication No. 60-26754).

[0017]

[Problems to be solved by the device]

 By the way, in the above-mentioned split mold forming method, by forming and joining a half-thickness joint at each end of each resin-molded part to be joined, the joint of the resin-molded part is formed. A wall thickness changing portion occurs at the boundary between the adjacent portion and the joint portion. On the other hand, spot welding is performed mainly at the center of the welded portion, and since welding is not performed at this wall thickness changing portion, the outer surface of this wall thickness changing portion may not be welded due to residual stress of welding or the like. This will cause injuries and sledges, and spoil the aesthetics of the product.

Further, as described above, since the recess (gap) formed on the outer surface of the joint is finally finished by filling it with an adhesive or the like, the following inconvenience occurs.

That is, when the recesses are filled with an adhesive and then baked and then painted, the air mixed in the adhesive expands due to the heat at the time of painting, causing peeling of the coating film (paint film) and coating surface. May cause pinholes. In this case, the aesthetics of the product will be impaired, so after the recesses have been corrected again with an adhesive and dried, the outer surface is finished smooth and repainted.

However, since the product requiring the above-mentioned correction is first discovered by heating in the painting process, after the discovery, the process is returned to the above-mentioned bonding work, and the above-described series of processes is performed again. Since it is repeated, many processes are duplicated and productivity is deteriorated.

In order to improve this, at present, a correction process is provided before the painting process, in which the joint is preheated to expand the air mixed in the adhesive, and only the product having the air mixed in the joint in advance is provided. It is selected, and a correction process with the above-mentioned adhesive is added to the portion again. Then, only the product with no mixed air is sent to the next painting process for baking coating.

However, in terms of actual manufacturing, the ratio of the products requiring the above-mentioned correction or re-modification to the whole products is high, and as a result, the production cost increases and above all, a large amount of the repair process is required. The current situation is that space is required. Especially in the repair process, the adhesive must be stored for the drying time (about 12 hours), and a large volume of one product such as cowling requires a lot of space.

The object of the present invention is to manufacture an integrated resin molded product by welding the joints of a plurality of resin molded parts with molten resin in a mold, and to mix air into the joints. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and an apparatus for joining resin-molded parts, which eliminates the above-mentioned problems, does not cause the above-mentioned inconvenience in the coating process, and can simply and beautifully finish the appearance of the joint.

[0024]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention is a method for joining resin-molded parts, in which a plurality of resin-molded parts are welded together by molten resin to have almost the same thickness, and are integrated. At each end to be formed, a joining portion thinner than the thickness in the vicinity thereof is formed, and the above resin is applied from both sides by a die composed of an upper die and a lower die that covers only the joining portion and its vicinity. A method for joining resin-molded parts, characterized by covering a joint part of a molded part, injecting a molten resin into the mold, and welding and joining the joint parts to be joined by the molten resin. And a holding base for holding a plurality of resin molded parts at predetermined positions during welding, and a thickness provided in the vicinity of the holding base and thinner than the thickness in the vicinity formed at each end of the resin molded parts to be connected. Only the broken joint and its vicinity In both cases, a die composed of an upper die and a lower die that forms a space between the inner wall of the die and the above-mentioned joint part at the time of fitting, and these die are relatively fitted and released during welding. And an injection molding machine in which an injection port communicates with the space to weld the above-mentioned joint portion with substantially the same thickness. To do.

[0025]

[Action]

 By the joining method having the above-mentioned configuration, a joining portion thinner than the thickness in the vicinity thereof is formed at each of the end portions to which the plurality of resin molded parts are to be connected, and the upper die for covering only the joining portion and the vicinity thereof is formed. A mold composed of a lower mold and a lower mold is covered from both sides, and a molten resin is injected into a space formed in the mold, and the molten resin welds the above-mentioned joints so that they are integrated. Therefore, the joining portion can be joined smoothly according to the space in the mold.

Further, since the entire surface portion of the joint portion is joined by the molten resin with a thickness substantially the same as that of the resin molded part, sinking or warping does not occur due to the stress due to the joining.

Furthermore, since the joining portions to be joined in the mold are fused with the molten resin, air is not mixed into the joining portions.

Further, the above-described series of joining methods can be carried out by the joining apparatus having the above configuration. That is, a plurality of resin-molded parts to be joined are held at predetermined positions by a holding table, and in this state, the actuating means actuates to join the respective joined parts formed on the end portions of the resin-molded parts. Only the part and its vicinity are covered from both sides by a mold composed of an upper mold and a lower mold. Then, the molten resin is injected from the injection molding machine into the space inside the mold, so that the respective joints of the resin molded parts are integrally welded with substantially the same thickness.

[0029]

【Example】

 The method and apparatus for joining resin-molded parts according to the present invention will be described below with reference to the drawings (FIGS. 1 to 10), taking the case of manufacturing a cowling for a motorcycle as an example.

FIGS. 1 and 2 show the shapes of the joints of the resin molded parts (resin molded parts forming the cowling) according to the first and second embodiments, and the resin molded parts to be welded together. It is the perspective view which looked at the state where the joined part of was contacted from the inner surface (back surface) side.

In FIG. 1, reference numerals 1 and 11 respectively denote two resin molded parts to be joined, and joint parts 2 and 12 are formed at respective end portions of the two resin molded parts 1 and 11. ing. In the case of this embodiment, the joint portions 2 and 12 are formed in the vicinity of the resin molding parts 1 and 11 by forming the step-shaped cross-section changing portion 4 at the inner surface side end portions (the cross-section changing portion 4 of Joined portion side: It is configured to be thinner than the thickness of both ends in FIG. Further, the edge portions 3 and 13 of the joint portions 2 and 12 are formed into edge shapes that are thin at the end portions like “grooves” in welding.

Further, in FIG. 2, reference numerals 2 and 12 denote joint portions, and in the case of the joint portions 2 and 12, unlike the joint portion of FIG. 1, the cross-section changing portion 4 to the edge portion 3 of the resin molded component 1, 11 are provided. The thickness is gradually reduced toward 13 and 13.

The joining portions 2 and 12 shown in FIGS. 1 and 2 are welded to each other by the molten resin R injected from the injection molding machine by a joining device to be described later, so that the integrated cowling C is formed. Is formed.

Even if the cowling C formed by the welding is welded at the joints 2 and 12 having any of the configurations shown in FIG. 1 or 2, the joints 2 and 12 are thinner than the thickness in the vicinity thereof. Therefore, after being welded, the joints 2 and 12 of the resin molded parts 1 and 11 have the same thickness as the thickness of the vicinity thereof. In addition, the above-mentioned welding is performed by the molten resin on the entire surface of the joint (more accurately, the entire surface of the contact surface and the inner surface (rear surface)). Therefore, there is no need for post-processing (finishing), and sink marks or warpage hardly occur at the cross-section changing portion 4 of the joint portions 2 and 12.

In particular, as shown in FIG. 2, if the cross sections of the joints 2 and 12 are gradually changed, internal stress or the like may be concentrated on the cross-section change section 4 as compared with the case of the configuration shown in FIG. Since the number is smaller, sinking or warping of the cross-section change portion 4 is more difficult to occur.

By the way, the apparatus shown in FIGS. 9 and 10 is a joining apparatus (welding apparatus) for welding the resin molded parts 1 and 11 having the above-described configuration.

In FIGS. 9 and 10, reference numeral 31 is a base of the present apparatus placed on the floor surface 30, a C-shaped frame 32 is disposed on the base 31, and further on the C-shaped frame 32. A slide bed 33 is arranged in the. A holding table 34 for holding the cowling C is slidably mounted on the slide bed 33 by a hydraulic cylinder 37, and a lower mold 35b forming a mold 35 is arranged on the upper part of the holding table 34. Has been done. Therefore, the lower die 35b is expanded and contracted by the hydraulic cylinder 37 so that the upper and lower sides of the holding bed 34 and the slide bed 33 below the holding bed 34 are in the front-back direction of the apparatus as shown by the solid line and the chain double-dashed line in FIG. Slide (left and right in FIG. 9).

Further, on the upper part of the C-shaped frame 32, the rod portion of the cylinder portion of the hydraulic cylinder 36 as an operating means for engaging and disengaging the mold 35 can be expanded and contracted downward. It is arranged. An upper die 35a is arranged at the tip of the rod 36a of the cylinder 36. Therefore, the upper mold 35a is configured to be movable upward and downward by expanding and contracting the rod 36a of the hydraulic cylinder 36, as shown by the solid line and the chain double-dashed line in FIG.

An injection molding machine 38 is provided near the center on the back side of the C-shaped frame 32, and the injection port 38 a of the injection molding machine 38 is located near the fitting surface 35 c of the mold 35. It is connected to a sprue (not shown).

By the way, in the case of the present embodiment, the mold 35 is formed by fitting so that the joint portions 2 and 12 (see FIGS. 1 and 2) have the same thickness as the vicinity thereof. The internal space is formed to have the same thickness as the vicinity of the end of the resin molded part.

In FIG. 9, reference numeral 39 is a work table when the cowling C is attached to and detached from the holding table 34.

Therefore, when welding the joints 2 and 12 of the resin molded parts 1 and 11 with the apparatus having the above-described configuration, first, as shown by the chain double-dashed line in FIG. The upper die 35a is contracted to raise the upper die 35a, and the hydraulic cylinder 37 is extended to move the lower die 35b (holding table 34) to the left end in FIG. In this state, the resin molded parts 1 and 11 to be welded are placed on the upper part of the lower mold 35b. At this time, as shown in FIG. 10, the plurality of support arms 34a provided below the holding table 34 hold the resin molded components 1 and 11 on the holding table 34 in a predetermined position.

Then, the holding cylinder 34 is moved to a predetermined position on the right side in FIG. 9 by contracting the hydraulic cylinder 37.

In this way, when the holding table 34 is set at the predetermined position, the rod 36a of the hydraulic cylinder 36 is extended and the upper die 35a is lowered. Then, when the upper mold 35a is completely lowered, the joint portions 2 and 12 (see FIGS. 1 and 2) of the resin molded parts 1 and 11 are covered from above and below by the upper mold 35a and the lower mold 35b.

By the series of operations described above, the preparation for welding the joints 2 and 12 (see FIGS. 1 and 2) is completed.

When the welding preparation is completed, the joints 2 and 12 of the two resin molded parts 1 and 11 are joined by the upper die 35a and the lower die 35b as shown in the sectional view of FIG. The periphery of 2 and 12 is sandwiched from above and below, and at this time, there is a space S between the inner wall of the mold 35a and the joints 2 and 12, and a small gap S ′ between the joint 2 and the joint 12. Is formed.

When the preparation for welding is completed in this way, the apparatus injects the molten resin R (see FIGS. 1 and 2) from the injection port 38a of the injection molding machine 38. The molten resin R may be a resin different from the resin molded parts 1 and 11 as long as it can be welded, but it is preferable to use the same resin as the resin molded parts 1 and 11. Alternatively, a resin in which a reinforcing fiber such as carbon fiber is mixed may be used.

The injected molten resin R flows from a gate (not shown) in the mold 35 into the space S and the gap S ′ between the joints 2 and 12, and welds the joints 2 and 12. Two resin molded parts 1 and 11 are integrated.

Then, the molten resin R is solidified to complete the welding (see FIGS. 3 and 4).

The series of operations described above is controlled by an operator's operation and a control device (not shown).

By the way, instead of the above-mentioned joints 2 and 12, as shown in the sectional view of FIG. 4 and the enlarged cross-sectional view of the main part of FIG. By forming a protrusion 5 near the edges 3 and 13 that is equal to or slightly protruding from the thickness of the portions near the joints 2 and 12 of the resin molded parts 1 and 11, the joint 2 is formed by the mold 35 described above. It is possible to prevent the upper ends of the protrusions 5 and the inner wall surface of the mold from contacting each other when they are sandwiched, and the joints 2 and 12 from trying to float up inside the mold 35. It is possible to hold (press) in place.

As a result, it is possible to prevent the joints 2 and 12, particularly the edges 3 and 13 thereof, from rising during the injection molding, and to prevent the molten resin R from reaching the portion where the joints 2 and 12 and the mold 35 should originally come into contact with each other. It is possible to prevent the flow.

Further, at the time of welding, the outer peripheral surface of the projection 5 is also welded to the molten resin R, and the welding area is increased, so that the resin molded parts 1 and 11 are not integrated more. It

As shown in FIG. 6, a plurality of the projections 5 are formed near the centers of the edge portions 3 and 13 and the joint portions 2 and 12, and the entire joint portions 2 and 12 are molded with a mold. 35 You may make it press against the inner wall surface.

In the above embodiment, a plurality of protrusions 5 are formed in a cylindrical shape, but as shown in FIG. 7, square protrusions 5A may be formed on the edges 3 and 13. Is not particularly limited.

Further, as shown in FIG. 8, if the welded surfaces of the thin joints 2 and 12 are formed in a corrugated shape, the welded area can be increased. As compared with the case where the welding surfaces of the joints 2 and 12 are formed flat, the same welding strength can be obtained even if the length of the joints 2 and 12 is shortened.

Generally, after a plurality of resin molded parts 1 and 11 are integrated by the above-mentioned method, a desired color is applied in a coating process to complete a resin molded product, but a material that does not require a coating process (for example, , Polypropylene, etc.) are used, the gaps (see FIGS. 2 to 8) formed between the abutting portions of the joint portions 2 and 12 of the plurality of resin-molded components 1 and 11 of the same color are different from each other. If the molten resin R 1 is injected and welded, a line of the color of the molten resin R 1 can be formed in the gap between the colors of the resin molded parts 1 and 11.

Further, even when the resin molded parts 1 and 11 of different colors are welded together to be integrated, if they are welded with the same molten resin R as either of the resin molded parts 1 and 11, they are joined together. A beautiful resin molded product of parts 2 and 12 can be obtained.

In the mold 35 described in the above-described embodiment, the molten resin injected from the injection port 38a provided in the vicinity of the fitting surface 35c of the mold 35 is a runner provided in the mold 35. The structure is such that it flows through the space S or S ′ into the space S or S ′, but by forming many runners, the orientation of the resin can be made the same direction as the orientation of the resin molded parts 1 and 11, and The strength and aesthetics of the joints 2 and 12 can be further improved.

Further, in this embodiment, since the cowling C having the two-divided structure is welded, the effective width of the mold 35 is also the width of the joints 2 and 12 (see FIGS. 3 and 4). It suffices that the resin molded parts 1 and 11 have a sufficient width so that the molten resin R does not flow out of the joints 2 and 12 without fail. Therefore, the mold itself may be small, and the manufacturing cost of the mold 35 is low.

If unevenness is formed on the surface of the upper mold 35a within a range where there is no influence of sink marks, etc., unevenness can be formed on the surfaces of the joint portions 2 and 12, and the outer surface of the resin molded product can be formed. It is also possible to form an uneven pattern.

The present invention is not limited to the device for welding the resin-molded parts having the two-part construction as described above, and it is also possible to configure so that a plurality of resin-molded parts can be welded. Is.

[0063]

[Effect of the device]

 According to the present invention, as described above, the joint portion which is thinner than the thickness in the vicinity formed at the end portion of the plurality of resin molded parts is melted in the space formed between the joint portion and the inner wall of the mold. Since the welding is performed by injecting the grease, it is possible to prevent air from entering the joint.

Therefore, unlike the conventional case, it is not necessary to provide a correction step, the productivity of the resin molded product is remarkably increased, and the manufacturing space required for the correction step is not required.

As a result, the production cost can be significantly reduced.

Further, since the joint portion of the resin molded component can be welded with the molten resin so as to have substantially the same thickness as that of the resin molded component, a sink mark or a warp does not occur in the cross-section change portion of the resin molded component after welding. It is possible to manufacture resin molded products with a beautiful appearance.

The joining apparatus for carrying out this joining method also has a holding base for holding the resin-molded component, a joint formed at the end of the resin-molded component, and a sufficient extent to cover only the vicinity thereof. Since it is sufficient to provide a small mold and an injection molding machine for injecting the molten resin, not only the mold but also the entire joining device can be downsized.

Therefore, the device itself can be provided at low cost.

[Submission date] April 20, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content] [Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure for joining a plurality of resin-molded parts with a molten resin, and more specifically, a joining structure for manufacturing a desired resin-molded product by fusing the ends of the plurality of resin-molded parts to integrate them. It is about.

[0002]

[Prior Art]

 Conventionally, as a method of manufacturing a resin molded product, a method of integrally molding a target product to obtain a target product (hereinafter referred to as an integral molding method) and a plurality of parts separately There is a method (hereinafter, referred to as a split-type molding method) of forming a desired product by molding and fusing these molded parts together by welding.

The above-mentioned integral molding method is intended to manufacture a mold capable of accommodating a product capable of integrally manufacturing the entire product, and inject a molten resin into the mold. Manufacture the product. The product produced by this method has no joints and has a beautiful appearance.

However, since the entire product is integrally molded, when the product is large, the die becomes very large, and as a result, the entire molding apparatus becomes large. Further, in this case, a large space for installing the device is required. Further, technically, it is difficult for a large-sized mold to provide high precision over a wide molding surface, and furthermore, the upper mold and the lower mold that are fitted together during molding are integrated. In the case where the product has a complicated shape, it may be very difficult in terms of manufacturing technology to form the divided parts and the divided shape, and it may be very difficult to manufacture the mold. Further, even in the case of a manufacturable shape, enormous cost is required for manufacturing a device including a mold and the like for the reason described above.

On the other hand, in the split mold molding method, as described above, the entire product is integrally molded by welding a plurality of separate molded parts between their respective ends to be connected. .. For this reason, the joint appears in the appearance. However, on the other hand, there is an advantage that it is not necessary to manufacture a large mold capable of accommodating the entire product, and thus a large molding device is not required. Also, in this method, if there is a welding device for welding the joints, the entire molding is possible, so the molding device for molding each molded part and the mold of each part can be relatively small. It also has the advantage of low manufacturing cost.

As described above, each of the above-mentioned two molding methods has its own characteristics. Generally, the integral molding method is used for manufacturing a relatively small product or a product having a relatively simple shape. The split-type molding method is used when manufacturing a product having a relatively large size and a complicated shape.

By the way, as one of the products manufactured by resin molding, there is a cowling of a motorcycle. In recent years, the cowling covers from the upper part of the handle to the lower part of the engine in view of reduction of air resistance and aesthetics. Many of them are large in size, and the shape is complicated to reduce air resistance as much as possible.

As described above, the above-described split-type molding method is used for manufacturing the large-sized and complicated-shaped cowling for the reasons described above.

The main welding methods for motorcycle cowlings used in the current split-type molding method are the first method shown in FIGS. 11 and 12 and the first method shown in FIGS. 13 and 14. There is a second method.

As shown in FIGS. 11 and 12, the first welding method attempts to connect the end portions of the two molded parts 51 and 61, one from the outer surface side and the other from the inner surface side. Formed are joints 52 and 62 each having a half-thickness projecting in the direction of the parts. With these joints 52 and 62 joined together, the ultrasonic welding machine is applied to multiple points of the joined parts. By welding (the welded portion is indicated by a cross in the figure) to integrate them.

As shown in FIGS. 13 and 14, the second welding method is to join the joints 52 and 62 of the two molded parts 51 and 61 in a butted state, and to join the joints to the inner surface. The reinforcing plate 55 is brought into close contact (so-called backing) from the (back surface), and the overlapped portions (overlapping portions) 56 and 66 are welded by an ultrasonic welding machine (mark the welded portion with a cross in the figure). It is to be integrated).

In all of the conventional welding methods as described above, so-called spot welding is performed by an ultrasonic welding machine on the overlapping portion with the end faces of the two joints abutting each other on the outer surface side of the joint. It is a thing.

Therefore, a gap (referred to as a concave portion; for example, a concave portion 54) is formed on the outer surfaces of the joint portions of the two joint portions. Therefore, after welding, the concave part (54) formed on the outer surface of the joint is filled with an adhesive to close the gap, and after drying, the adhesive that protrudes from the outer surface of the joint and solidifies is scraped off and polished to smooth the surface. Is finished.

After that, the cowling in which the above-mentioned joints are finished and integrated is sent to a coating process, and a desired coating color is applied to form a final product (component; cowling).

As a prior art of this type, “a method for manufacturing a fairing” for preventing reduction of strength of a divided portion in a welded portion of a molded part and preventing a deviation or a step at this portion (Japanese Patent Publication No. 60-26754).

[0016]

[Problems to be solved by the device]

 By the way, in the above-mentioned split mold forming method, by forming and joining a half-thickness joint at each end of each resin-molded part to be joined, the joint of the resin-molded part is formed. A thickness change portion is formed at the boundary between the adjacent portion and the joint portion. On the other hand, spot welding is performed mainly at the central portion of the joint, and since welding is not performed at this wall thickness changing portion, the outer surface of this wall thickness changing portion may be affected by residual welding stress, etc. This will cause injuries and sledges, and spoil the aesthetics of the product.

Further, as described above, since the recess (gap) formed on the outer surface of the joint is finally finished by filling it with an adhesive or the like, the following inconvenience occurs.

That is, when the recesses are filled with an adhesive and then baked and then painted, the air mixed in the adhesive expands due to the heat at the time of painting, resulting in peeling of the coating film (paint film) and coating surface. May cause pinholes. In this case, the aesthetics of the product will be impaired, so after the recesses have been corrected again with an adhesive and dried, the outer surface is finished smooth and repainted.

However, since the product requiring the above-mentioned correction is first discovered by heating in the painting process, after the discovery, the process is returned to the above-mentioned bonding work, and the above-described series of processes is performed again. Since it is repeated, many processes are duplicated and productivity is deteriorated.

In order to improve this, at present, a correction process is provided before the painting process, in which the joint is preheated to expand the mixed air in the adhesive, and only the product having the mixed air in the joint in advance. It is selected, and a correction process with the above-mentioned adhesive is added to the portion again. Then, only the product with no mixed air is sent to the next painting process for baking coating.

However, in the actual manufacturing, the ratio of the products requiring the above-mentioned modification or re-modification to the whole products is high, and as a result, the production cost is increased and, above all, a large amount of the repair process is required. The current situation is that space is required. Especially in the repair process, the adhesive must be stored for the drying time (about 12 hours), and a large volume of one product such as cowling requires a lot of space.

The object of the present invention is to manufacture an integrated resin molded product by welding the joints of a plurality of resin molded parts with molten resin in a mold, and to prevent air from entering the joints. It is an object of the present invention to provide a joint structure for resin molded parts that eliminates the above-mentioned inconvenience in the painting process and can easily finish the appearance of the joint beautifully.

[0023]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the joint structure of resin molded parts in the present invention is a joint structure of resin molded parts in which the ends of a plurality of resin molded parts are fused and integrated with a molten resin at substantially the same thickness. Therefore, each end of the resin molded part to be connected is provided with a joint that is thinner than the thickness in the vicinity thereof, and the protrusion has the same or almost the same height as the thickness of the end of the resin molded part. Is formed, and the joined portions are welded together with a molten resin with almost the same thickness to integrate them.

[0024]

[Action]

 According to the joining structure having the above-mentioned configuration, the end portions to be connected with the plurality of resin molded parts are provided with joint parts thinner than the thickness in the vicinity thereof, and the thickness of the end parts of the resin molded part is provided at the joint parts. Since a protrusion having the same or almost the same height as the above is formed, a space is formed in a state where the protrusion is in contact with the inner wall surface of the mold when the joint is covered from both sides with a mold. Then, the molten resin was injected into the space formed in this mold, and the molten resin was used to weld and integrate the above-mentioned joints, so that the joints have almost the same thickness and are smooth. Can be joined to. At this time, the protrusion prevents the edge of the joint from rising.

Further, since the entire surface portion of the joint portion is joined by the molten resin with substantially the same thickness as the resin-molded component, sink marks and warpage do not occur due to the joining stress.

Further, since the joining portions to be joined in the mold are welded by the molten resin, air is not mixed into the joining portions.

[0027]

【Example】

 Hereinafter, a joint structure of resin molded parts according to the present invention will be described with reference to the drawings (FIGS. 1 to 10), taking a case of manufacturing a cowling of a motorcycle as an example.

First, an outline of the joining structure according to the present invention will be described with reference to FIGS. 1 to 3. FIGS. 1 and 2 show the shape of the joining portion of a resin molded component (resin molded component forming a cowling). 3A and 3B are perspective views of a state in which a joint portion of a resin molded component to be welded is brought into contact with each other, as viewed from the inner surface (back surface) side.

In FIG. 1, reference numerals 1 and 11 respectively denote two resin molded parts to be joined, and joint parts 2 and 12 are formed at respective end portions of the two resin molded parts 1 and 11. ing. These joint portions 2 and 12 are formed in the vicinity thereof (on the side opposite to the joint portion of the cross-section changing portion 4; 1 is thinner than both end portions). Further, the edge portions 3 and 13 of the joint portions 2 and 12 are formed into edge shapes thinned at the end portions like “grooves” in welding.

Further, in FIG. 2, reference numerals 2 and 12 denote joint portions, and in the case of the joint portions 2 and 12, unlike the joint portion in FIG. 1, the cross-section changing portion 4 to the edge portion 3 of the resin molded component 1, 11 are provided. The thickness is gradually reduced toward 13 and 13.

Then, as shown in the sectional view of FIG. 3, the joint portions 2 and 12 of FIGS. 1 and 2 are clamped from above and below by an upper die 35a and a lower die 35b of a joining device which will be described later. Then, the joint portions 2 and 12 are welded by the molten resin R, whereby an integral cowling C is formed.

Even if the cowling C formed by the welding is welded at the joints 2 and 12 having any of the configurations shown in FIG. 1 or 2, the joints 2 and 12 are thinner than the thickness in the vicinity thereof. Therefore, after being welded, the joints 2 and 12 of the resin molded parts 1 and 11 have the same thickness as the thickness of the vicinity thereof. In addition, the above-mentioned welding is performed by the molten resin on the entire surface of the joint (more accurately, the entire surface of the contact surface and the inner surface (rear surface)). Therefore, there is no need for post-processing (finishing), and sink marks or warpage hardly occur at the cross-section changing portion 4 of the joint portions 2 and 12.

In particular, as shown in FIG. 2, if the cross sections of the joints 2 and 12 are gradually changed, internal stress or the like may be concentrated in the cross-section change section 4 as compared with the case of the configuration shown in FIG. Since the number is smaller, sinking or warping of the cross-section change portion 4 is more difficult to occur.

In the present invention constructed as described above, in the vicinity of the edges 3 and 13 of the joints 2 and 12, the protrusions 5 which are the characteristic parts of the present invention are joined to the resin molded parts 1 and 11. An embodiment formed so as to have a thickness equal to or slightly protruding from the portions near the portions 2 and 12 will be described below with reference to the sectional view of FIG. 4 and the enlarged sectional view of the main part of FIG.

As shown in the drawing, in the vicinity of the edge portions 3 and 13 of the joint portions 2 and 12 of the resin molded components 1 and 11 described above, the thickness of the portions near the joint portions 2 and 12 of the resin molded components 1 and 11 and Protrusions 5 that are equal or slightly projecting are formed. By forming the protrusions 5 in this way, when the joints 2 and 12 are sandwiched by the above-mentioned mold 35, the upper ends 5a of the protrusions 5 and the inner wall surface of the mold contact each other, and the joints It is possible to prevent the 2 and 12 from trying to float in the mold 35, and it is possible to hold (press) at a predetermined position in the mold.

As a result, it is possible to prevent the joints 2 and 12, particularly the edges 3 and 13 thereof, from rising during the injection molding, and to prevent the molten resin R from reaching the portion where the joints 2 and 12 and the mold 35 should originally come into contact with each other. It is possible to prevent the flow.

Further, at the time of welding, the outer peripheral surface of the protrusion 5 is also welded to the molten resin R, and the welding area is increased, so that the resin molded parts 1 and 11 are not integrated more. It

As shown in FIG. 6, a plurality of the projections 5 are formed near the centers of the edge portions 3 and 13 and the joint portions 2 and 12, and the entire joint portions 2 and 12 are molded by a mold. 35 You may make it press against the inner wall surface.

In the above embodiment, a plurality of protrusions 5 are formed in a cylindrical shape, but as shown in FIG. 7, square protrusions 5A may be formed on the edges 3 and 13. Is not particularly limited.

Further, as shown in FIG. 8, if the welding surfaces of the thinned joints 2 and 12 are formed in a corrugated shape, the welding area can be increased. As compared with the case where the welding surfaces of the joints 2 and 12 are formed flat, the same welding strength can be obtained even if the length of the joints 2 and 12 is shortened.

The apparatus shown in FIGS. 9 and 10 is a joining apparatus (welding apparatus) for welding the resin molded parts 1 and 11 having the above-described configuration.

In FIGS. 9 and 10, reference numeral 31 is a base of the present apparatus placed on the floor surface 30, a C-shaped frame 32 is disposed on the base 31, and further on the C-shaped frame 32. A slide bed 33 is arranged in the. A holding table 34 for holding the cowling C is slidably mounted on the slide bed 33 by a hydraulic cylinder 37, and a lower mold 35b forming a mold 35 is arranged on the upper part of the holding table 34. Has been done. Therefore, the lower die 35b is expanded and contracted by the hydraulic cylinder 37 so that the upper and lower sides of the holding bed 34 and the slide bed 33 below the holding bed 34 are in the front-back direction of the apparatus as shown by the solid line and the chain double-dashed line in FIG. Slide (left and right in FIG. 9).

Further, on the upper portion of the C-shaped frame 32, the cylinder portion of the hydraulic cylinder 36 as an operating means for fitting and disengaging the die 35 is arranged so that the rod portion thereof can extend and contract downward. It is arranged. An upper die 35a is arranged at the tip of the rod 36a of the cylinder 36. Therefore, the upper mold 35a is configured to be movable upward and downward by expanding and contracting the rod 36a of the hydraulic cylinder 36, as shown by the solid line and the chain double-dashed line in FIG.

An injection molding machine 38 is provided near the center on the back side of the C-shaped frame 32. The injection port 38a of the injection molding machine 38 is located near the fitting surface 35c of the mold 35. It is connected to a sprue (not shown).

In the above example, the mold 35 has an internal space formed by fitting so that the joints 2 and 12 (see FIG. 4) have the same thickness as the vicinity thereof. Is formed to have the same thickness as the vicinity of the end portion of.

Further, in FIG. 9, reference numeral 39 denotes a work table when the cowling C is attached to and detached from the holding table 34.

Therefore, when welding the joints 2 and 12 of the resin molded parts 1 and 11 with the device having the above-described configuration, first, as shown by the chain double-dashed line in FIG. The upper die 35a is contracted to raise the upper die 35a, and the hydraulic cylinder 37 is extended to move the lower die 35b (holding table 34) to the left end in FIG. In this state, the resin molded parts 1 and 11 to be welded are placed on the upper part of the lower mold 35b. At this time, as shown in FIG. 10, the plurality of support arms 34a provided below the holding table 34 hold the resin molded components 1 and 11 on the holding table 34 in a predetermined position.

Then, the holding cylinder 34 is moved to a predetermined position on the right side in FIG. 9 by contracting the hydraulic cylinder 37.

In this way, when the holding table 34 is set at a predetermined position, the rod 36a of the hydraulic cylinder 36 is extended and the upper die 35a is lowered. Then, when the upper mold 35a is completely lowered, the joints 2 and 12 (see FIGS. 4 and 5) of the resin molded parts 1 and 11 are covered from above and below by the upper mold 35a and the lower mold 35b.

By the series of operations described above, the preparation for welding the joints 2 and 12 (see FIGS. 4 and 5) is completed.

When the welding preparation is completed, the joint portions 2 and 12 of the two resin molded parts 1 and 11 are joined by the upper die 35a and the lower die 35b as shown in the sectional view of FIG. The periphery of 2 and 12 is sandwiched from above and below, and at this time, there is a space S between the inner wall of the mold 35a and the joints 2 and 12, and a small gap S ′ between the joint 2 and the joint 12. Is formed.

When the welding preparation is completed in this way, the apparatus injects the molten resin R (see FIGS. 1 and 2) from the injection port 38a of the injection molding machine 38. The molten resin R may be a resin different from the resin molded parts 1 and 11 as long as it can be welded, but it is preferable to use the same resin as the resin molded parts 1 and 11. Alternatively, a resin in which a reinforcing fiber such as carbon fiber is mixed may be used.

The injected molten resin R flows from a gate (not shown) in the mold 35 into the space S and the gap S ′ between the joints 2 and 12, and welds between the joints 2 and 12. Two resin molded parts 1 and 11 are integrated. Then, the molten resin R is solidified to complete the welding (see FIGS. 3 and 4). At this time, the edge portions 3 and 13 are formed in an edge shape like the joint portions 2 and 12 shown in FIG. 1 or toward the edge portions 3 and 13 like the joint portions 2 and 12 shown in FIG. By gradually reducing the thickness and providing the gap S ′ between the joint portions 2 and 12, the welding at the edge portions 3 and 13 can be facilitated and the welding at the edge portions 3 and 13 can be strengthened.

The series of operations described above is controlled by an operator's operation and a control device (not shown).

In general, a plurality of resin molded parts 1 and 11 are integrated by the above-mentioned method, and then a desired color is applied in a coating process to complete a resin molded product, but a coating process is not required. When a material (for example, polypropylene) is used, a gap formed between the contact portions of the joint parts 2 and 12 of a plurality of resin molded parts 1 and 11 of the same color (see FIGS. 2 to 8). In addition, if the molten resin R of another color is injected and welded, a line of the color of the molten resin R can be formed in the gap between the colors of the resin molded parts 1 and 11.

Further, even when resin molded parts 1 and 11 of different colors are welded together to be integrated, if they are welded with the same molten resin R as either resin molded part 1 or 11, they are joined together. A beautiful resin molded product of parts 2 and 12 can be obtained.

In the mold 35 described above, the molten resin ejected from the injection port 38 a provided in the vicinity of the fitting surface 35 c of the mold 35 passes through the runner provided in the mold 35 and the space S Alternatively, although it is a structure that flows into S ′, by forming a large number of these runners, the orientation of the resin can be made the same direction as the orientation of the resin molded parts 1 and 11, and as a result, the joint 2 , 12 can also improve the strength and aesthetics.

Further, in this embodiment, since the cowling C having the two-divided structure is welded, the effective width of the mold 35 is also the width of the joints 2 and 12 (see FIGS. 3 and 4). It suffices that the resin molded parts 1 and 11 have a sufficient width so that the molten resin R does not flow out of the joints 2 and 12 without fail. Therefore, the mold itself may be small, and the manufacturing cost of the mold 35 is low.

If unevenness is formed on the surface of the upper mold 35a within a range where there is no influence of sink marks, etc., unevenness can be formed on the surfaces of the joints 2 and 12, and the outer surface of the resin molded product can be formed. It is also possible to form an uneven pattern.

The present invention is not limited to the apparatus for welding resin-molded parts having the above-described two-divided structure, and a plurality of resin-molded parts may be welded. Is.

[0061]

[Effect of the device]

 According to the present invention, as described above, when the joint formed on the end to which the plurality of resin molded parts are to be connected is covered with the mold from both sides, the protrusion formed on the joint comes into contact with the inner wall surface of the mold. Since a space is formed in this state, molten resin is injected and welded in a state where the edge of the joint portion is in contact with the mold surface by the protrusion. Therefore, the joint portion can be smoothly joined with substantially the same thickness. At this time, the protrusion prevents the edge of the joint from rising.

Further, since the joining portions to be joined in the mold are welded with the molten resin, it is possible to prevent air from entering the joining portions. Therefore, unlike the conventional case, it is not necessary to provide a repair process, the productivity of the resin molded product is significantly increased, and the manufacturing space required for the repair process is not required. And this can also significantly reduce the production cost.

Furthermore, since the joint portion of the resin-molded component can be welded by the molten resin so as to have substantially the same thickness as that of the resin-molded component, sink marks or warpage will not occur in the cross-section change portion of the resin-molded component after welding. It is possible to manufacture resin molded products with a beautiful appearance.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration (shape) of a joint portion of a resin molded component used in an embodiment of the present invention, as viewed from the inner surface (back surface) side.

FIG. 2 is a perspective view showing a configuration (shape) of a joint portion of a resin molded component of another embodiment different from FIG. 1 as seen from the inner surface (back surface) side.

FIG. 3 is a cross-sectional view showing the relationship between the bonding portion and the mold when the bonding portion is covered with the mold.

FIG. 4 is a cross-sectional view showing another embodiment different from FIG.

5 is an enlarged cross-sectional view of the main parts of FIG.

FIG. 6 is a perspective view showing a configuration of a joint portion of a resin molded component of another embodiment different from FIG. 1 as seen from the inner surface (back surface) side.

FIG. 7 is a perspective view showing a configuration of a joint portion of a resin molded component of another embodiment different from FIG. 1 as seen from the inner surface (back surface) side.

FIG. 8 is a perspective view showing a configuration of a joint portion of a resin molded component of another embodiment different from FIG. 1, as viewed from the inner surface (back surface) side.

FIG. 9 is a side view showing the configuration of the joining device according to the embodiment of the present invention.

10 is a cross-sectional view taken along the line AA of FIG.

FIG. 11 is a perspective view showing a welding method of a first conventional example.

12 is a sectional view of a welded portion of FIG.

FIG. 13 is a perspective view showing a welding method of a second conventional example.

14 is a cross-sectional view of the welded portion of FIG.

[Explanation of symbols]

 1, 11… Resin molded parts 2, 12… Joined parts 3, 13… Edge part 4… Cross section change part 5… Protrusion 30… Floor surface 31… Base 32… C type frame 33… Slide bed 34… Holding stand 35… Mold 35a… Upper mold 35b… Lower mold 36… Hydraulic cylinder 37… Hydraulic cylinder 38… Injection molding machine 38a… Injection port C… Cowling R… Melted resin S… Space

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[Procedure amendment]

[Submission date] April 20, 1993

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of device] Joint structure of resin molded parts

[Scope of utility model registration request]

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration (shape) of a joint portion of a resin molded component according to the present invention, as viewed from the inner surface (back surface) side.

FIG. 2 is a perspective view, as viewed from the inner surface (back surface) side, showing a schematic configuration (shape) of a joint portion of a resin molded component according to the present invention, which is different from FIG.

FIG. 3 is a cross-sectional view showing a state in which the bonding portion shown in FIG. 1 is covered with a mold.

FIG. 4 is a cross-sectional view showing a state in which a joint portion of a joint structure for resin molded parts according to the present invention is covered with a mold.

5 is an enlarged cross-sectional view of an essential part showing a joint part of the resin molded part shown in FIG.

FIG. 6 is a perspective view of an embodiment of the joint portion according to the present invention as viewed from the inner surface (back surface) side.

FIG. 7 is a perspective view of another embodiment of the joint portion according to the present invention viewed from the inner surface (back surface) side.

FIG. 8 is an inner surface of another embodiment of the joint portion according to the present invention.
It is a perspective view seen from the (back) side.

FIG. 9 is a side view showing a joining device for joining a joint portion of a resin molded component according to the present invention.

10 is a cross-sectional view taken along the line AA of FIG. 9 showing the joining device.

FIG. 11 is a perspective view showing a first example of a conventional welding method.

12 is a sectional view of a welded portion of FIG.

FIG. 13 is a perspective view showing a second example of a conventional welding method.

14 is a sectional view of the welded portion of FIG.

[Explanation of reference numerals] 1 and 11 ... Resin molded parts 2 and 12 ... Joined portions 3 and 13 ... Edge portion 4 ... Cross-section change portion 5 ... Protrusion 30 ... Floor surface 31 ... Base 32 ... C-shaped frame 33 ... Slide bed 34 ... Holding table 35 ... Mold 35a ... Upper mold 35b ... Lower mold 36 ... Hydraulic cylinder 37 ... Hydraulic cylinder 38 ... Injection molding machine 38a ... Injection port C ... Cowling R ... Molten resin S ... Space

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (1)

[Scope of utility model registration request] 1. A holding base for holding a plurality of resin molded parts at predetermined positions during welding, and a thickness provided near the holding base and formed near each end of the resin molded parts to be connected. A die composed of an upper die and a lower die that covers only the thinner joint and the vicinity thereof and forms a space between the inner wall and the joint at the time of fitting,
In addition to providing an operating means for relatively engaging and disengaging these molds at the time of welding, an injection molding machine having an injection port communicating with the space is provided to weld the joint portion with substantially the same thickness. A device for joining resin molded parts.