CN101332672A

CN101332672A - Laser welding connection of plastic pipe and other plastic parts

Info

Publication number: CN101332672A
Application number: CNA2008101250511A
Authority: CN
Inventors: T·恩贝勒; R·凯特尔; W·卡吉
Original assignee: EMS Patent AG
Current assignee: EMS Patent AG
Priority date: 2007-06-27
Filing date: 2008-06-25
Publication date: 2008-12-31
Also published as: JP4836993B2; DE102008017922A1; JP2009018576A; KR20080114613A; KR101469999B1; DE102008017922B4; CN103878974A

Abstract

The present invention relates to a laser welding method for establishing connection of plastic pipe (2) with plastic part (3), the method involves sticking together an end (4) of a plastic pipe (2) with an end (5) of a plastic part (3) in an overlapping manner, where the ends respectively exhibit an inner dimension (6) and/or outer dimension (7) in the area of connection of the plastic pipe with the plastic part, largest outer dimension of the ends lying inside the area of connection is larger than lowest inner dimension of the ends lying outside the area of connection, a contact pressure is formed between the ends, thus heat contact each other in the laser welding process is reinforced. According to the invention, the laser welding method is characterized in that installation ends (4) of the plastic pipe (2) and the plastic part (3) is mainly composed of polyamide without core shaft fixation, simultaneously the laser beam for welding is guided around the fixed pipe contact.

Description

Plastic tube is connected with the laser welding of other plastic components

Technical field

The present invention relates to a kind of laser welding method that is connected for preparing plastic tube and another plastic components, wherein an end of plastic tube overlap joint is installed on the tubulated ends of another plastic components, plastic tube end and plastic components end have inside dimension or external dimensions respectively at join domain, and the largest outer dimension of the inner is greater than the smallest internal dimension of outer end in this zone in the join domain, form contact pressure thus between both ends, this has strengthened mutual thermo-contact in the laser welding process.

Background technology

Connection between plastic tube and other plastic components for example is known in auto industry.Especially burning line, they must be connected with sealing and safe mode installed part and/or the fastener with the plastic tube that is used for transmitting fuel.Because the ethanol composition increases in the fuel, in burning line, often expand, therefore it is softer that burning line becomes thus, for example uses the conduit olive ring of knowing from DE 38 43 995 C2 (olives) or use traditional tie point of pine nut profile no longer can bear the pressure and the seal request of growth.Under the worst situation, the connection between pipeline and the joint (for example with quick attachment form occur) fluffs, so they relative to each other produce distortion, perhaps pipeline even come off from joint.Equally, also must make the consideration identical with fuel line to the fuel cools pipeline, owing to traditional jointing (pine nut profile) wherein also often because the increase of temperature and pressure lost efficacy.

Nowadays make just more and more and adopt this class of spin friction welding (referring to EP 0 635 670 B1) or gummed (referring to DE 103 36 494 A1) to connect.Yet, known because the particles agglomerate that the abrasion that this method produced is got off also can polluted pipeline by the pipeline of spin friction welding is inner.Also can produce in the pipeline by gummed and interfere particulate even obstruction.

Plastic tube uses the laser welding method can know from EP 1 403 030 A1 with being connected of another plastic components.The skin of the plastic tube end of another plastic components is made into laser opaquely by for example adding carbon black, calcium silicide or iron oxide, promptly absorbs laser.The one end overlap joint of plastic tube is incorporated into the tubulated ends of another plastic components.Be provided with the adapter of making by to the plastics of laser-light transparent (being laser-transmitting) thereon, so that the part of the tubulated ends of the part of its plastic covering pipe and another plastic components, and form good thermo-contact with these two cover parts.Use laser emission also therefore to use adapter (adapter) they to be connected by at least one periphery welded side seam in this zone-melting to each cover part heating.Another plastic components can be pipe, snap joint, arm, valve or pipe lid.

The laser plastic welding is generally that announce, the 23rd phase from Switzerland industry magazine " Technischen Rundschau " (Switzerland occupation medium AG, Wabern, Switzerland), 2004,

Know in the article of being entitled as of people such as Seiffert and Renner " Laser-Kunststoffschweissen in allen Farben[Laser Plastic Welding inAll Colors] ".Wherein mention the painted free degree that will be fused assembly especially and be restricted before this always, and the absorption of laser emission is to be determined by the embedding additive of for example pigment and/or pigment in most cases, rather than determine by polymer matrix.Because these light absorbents generally have tangible intrinsic color (for example being aterrimus under the situation of carbon black) equally in visible-range, therefore all must between art designs and color requirement, make compromise up to now.The common laser wavelength place of desirable laser light absorber in near-infrared (NIR) scope that is used for transparent plastic shows strong absorbent, do not have absorbability (yet promptly not having the macroscopic color of intrinsic color may not form interference) at visible-range, and do not have optical scattering.It does not influence the engineering properties, nontoxic of polymer matrix, even and can processedly handle under high injection temperature yet.The reason that the additive of Here it is laser welding is subjected to largely paying close attention to.On the other hand, if pigment is known (referring to the cited literature 2 from " Technischen Rundschau "), this allows laser beam to pass through conversely, but color is highlighted, and promptly the laser-light transparent color forms.If the intrinsic color of plastic components is that last application is desired, then this class laser-light transparent pigment can be used for the laser-transmitting welding of upper end in conjunction with homologue (upper join partner).

The application DE 103 04 071 of German published discloses the manufacturing of the assembly of two tubes at least, and the velamen in this two tubes pushes another root radially to cooperate and to carry out the point type laser welding.Yet owing to can't realize being tightly connected by the point type welding, therefore such connection can not guarantee passing through of in the pipe that is connected liquid or fluid.

The application DE 10 2,005 010 193 of German published discloses a kind of method and apparatus that is used for connecting the saving cost of the pipe that is made of plastics, and wherein uses incoherent light source (that is, not being laser).

According to classification the method that the end part that is made of plastics (coloured, have more low-density polyethylene head end) is connected in plastic body (polyethylene pipe transparent, that have higher density) can openly be applied for knowing the DE 2 261 388 from Germany.The end part by inner axis of heart supporting and during welding with the rotating speed rotation of 1500rpm.For the parts that make welding each other have tight as far as possible contact at inner surface,, preferably between the parts that will be fused, produce interference fit so that the least possible material fusion fuses two parts.Perhaps, can adopt the fin on the axle to contact between head and tube body, to form pressure.In any case, tube body and head are installed on the live spindle and are positioned to make the zone that will be fused to be positioned near the focus point of the lens that laser beam sees through.The surface of this axle is polished aptly, to realize the maximum reflection of laser beam.This method is used for straight line pipe or tubular body are fused to head or plastic components, but its shortcoming is must remove axle after welding, and this can cause many problems or especially for non-rectilinear pipe or even impossible.

Summary of the invention

The object of the present invention is to provide a kind of alternative method, this method can be utilized the advantage of laser welding method and avoid the shortcoming of connection known in the state of the art.

This purpose is by realizing according to laser welding method of the present invention according to the feature of independent claims 1.The laser welding method is used for preparing plastic tube is connected in the joint of another plastic components, wherein an end of plastic tube overlap joint is installed on the tubulated ends of another plastic components, plastic tube end and plastic components end have inside dimension or external dimensions respectively in join domain, and the largest outer dimension of the inner end in the join domain is greater than the smallest internal dimension of the outer end in this zone, form contact pressure thus between both ends, this has strengthened thermo-contact mutual in the laser welding process.Laser welding method according to the present invention is characterised in that the mounting end of plastic tube and another plastic components mainly is made of polyamide and does not use axle to fix, and the laser beam that is used for welding simultaneously is guided in around the fixing pipe joint.

In this laser welding method, the end of plastic components has inner surface or outer surface especially goodly, this surface comprises the alleviation structure that at least one reduces inside dimension or increases external dimensions, form the contact pressure that increases thus when two ends are installed, this has strengthened mutual thermo-contact in the laser welding process.

Further preferable feature according to the present invention is produced by dependent claims.

The advantage of the method according to this invention is as follows:

-by using pipeline and extinction joint (standardized product is black), obviously increase its fastening degree and joint tear edge to laser-light transparent.Can also after fuel reservoir, form greatly and strengthen.

-against existing technologies in known laser welding (referring to EP 1 403 030 A1), extra sleeve---is extra adapter---is unwanted.

-by using the alleviation structure on the joint, the thermo-contact between two assemblies that be fused is reinforced and has therefore strengthened welded side seam and/or welding point.

Description of drawings

The present invention is based on that the selected exemplary embodiment that scope of the present invention is not construed as limiting illustrated.In the accompanying drawings:

Fig. 1 illustrates according to first embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 2 illustrates according to second embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 3 illustrates according to the 3rd embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 4 illustrates according to the 4th embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 5 illustrates according to the 5th embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 6 illustrates according to the 6th embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 7 illustrates according to the 7th embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 8 illustrates according to the 8th embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Fig. 9 illustrates according to the 9th embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Figure 10 illustrates according to the tenth embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Figure 11 illustrates according to the 11 embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

Figure 12 illustrates according to the 12 embodiment, has the partial axial section of the hose transition branch of pushing plastic tube;

The specific embodiment

Fig. 1 illustrates use and is connected 1 according to another plastic components 3 of the plastic tube 2 of laser welding method of the present invention and preparation.Plastic tube 2 can be mono-layer tube or multilayer pipe.An end 4 overlap joints of plastic tube 2 are installed on the tubulated ends 5 of another plastic components 3.Plastic tube end 4 and plastic components end 5 have inside dimension 6 or external dimensions 7 respectively being connected 1 zone.Connect the smallest internal dimension 6 of the largest outer dimension 7 of the inner end 5 in 1 zone greater than outer end 4 in this zone.The smallest internal dimension 6 that the largest outer dimension 7 of this flexible pipe installing component preferably surpasses plastic tube end 4 at least 0.05mm (for example for the typical motor vehicle fuel pipeline that is made of plastics, internal diameter be 6mm and external diameter is 8mm), perhaps generally surpass at least 1%.Because this redundancy of largest outer dimension 7 has formed the contact pressure of strengthening mutual thermo-contact in the laser welding process between both ends 4,5.At least 5% redundancy is better, and at least 10% redundancy is preferred., with during laser welding shown in Figure 3 is connected plastic tube end 4 is pressed against on the plastic components end 5 at Fig. 1.Plastic components inner end 5 has the outer surface 8 that is embodied as at least the laser substantially transparent, and plastic tube end 4 at least in connection 1 zone of anticipation to the laser substantially transparent.Plastic tube end 4 therefrom sees through laser (zigzag arrow), the 5 radiation outer surfaces 8 and be pressed in plastic tube end 4 inner surfaces 9 above it and be heated and fuse up to the plastic components end, thus the welding area 10 of periphery fusion between plastic tube 2 and another plastic components 3, at least mainly formed at radiation position along the girth of two mounting ends 4,5.In the first and the 3rd embodiment that laser welding according to the present invention connects, the actual welded side seam (referring to Fig. 1 and Fig. 3) that only forms single-revolution edge and consequent sealing.Compare therewith, laser welding connection according to the present invention has dual periphery welded side seam (referring to Fig. 2) in a second embodiment.A welded side seam in these two welded side seams or can be implemented as the chain line (not shown) of the multiple spot welding that separates each other.

If do not form periphery welded side seam completely at all, and the point type welding only is used for mechanical fixation, then preferably with the use that connects of the rubber seal of O shape loop type and point type welding.For this sealing, a district in the overlap joint zone of plastic tube end 4 and plastic components end 5 is designed to adapt to it on how much.

As the replacement of the connection of point type welding or additional, generally also can adopt many weak points, non-periphery welded side seam.Three short welded side seams that preferably are evenly distributed on around the girth of plastic tube end 4 and/or plastic components end 5 and mainly follow the girth of an end in these two

ends

4,5 are preferred.

Fig. 2 illustrates use according to the connection 1 that laser welding method of the present invention forms, and wherein plastic tube end 4 is pressed against on the plastic components end 5.Here the plastic tube end 4 that illustrates comprises the internal layer 11 (for example use the black of carbon black and/or be configured to anlistatig) that is embodied as at least in connection 1 zone of anticipation the laser substantially transparent.In a single day the thickness of this layer 11 preferably is suitable for by laser the layer 11 radiationless outer surface 8 with plastic components end 5 being heated after being subjected to radiation and fusing (promptly still so thin), so that at least one welding area 10 is formed between radiant place plastic tube 2 and another plastic components 3.Internal layer 11 is preferably ESD layer (the ESD=static discharge), it is electrically connected and is being connected on 1 with the whole of another plastic components 3, and described another plastic components 3 equally is embodied as conduction here.The electric conductivity of ESD layer is to adopt additive known per se to realize, for example Dao Dian carbon black, carbon fiber, graphite fibre (CNT), steel fibre etc.

The 3rd embodiment (referring to Fig. 3) especially adopts the maintenance hook 17 that occurs with periphery fin form with two embodiment are different at first.This maintenance hook 17 is suitable for keeping plastic tube end 4 with respect to the chocking construction 18 that preferably is formed on the plastic components end 5 reliably, connects till 10 up to forming welding.In addition, the tear edge of the connection after the completion increases because of keeping hook 17.If necessary, can save the formation of chocking construction 18 (not shown).

Identical with previous drawings, Fig. 4 illustrates the axial partial cross section of the hose transition branch with pushing plastic tube.Be according to the 4th embodiment of laser welding connection of the present invention and the difference of front embodiment, plastic components end 5 has the outer surface 8 that contains at least one alleviation structure 14 that is used to increase external dimensions 7 (here with the appearance of periphery protuberance form), form the contact pressure that increases thus when both

ends

4,5 are installed, this has further strengthened mutual thermo-contact in the laser welding process.

Especially because alleviate structure 14, the minimum external dimensions 6 that largest outer dimension 7 usefully surpasses plastic tube end 4 nearly 1mm-4mm (in the typical motor vehicle fuel pipeline that is made of plastics, internal diameter be 6mm and external diameter is 8mm), or generally surpass 15%-70%.Because this redundancy of largest outer dimension 7, contact pressure is formed between the both

ends

4,5, and this has further strengthened during the laser welding thermo-contact each other.At least one periphery welding area 10 preferably is seated on the alleviation structure 14 of another plastic components 3.

In preferable test (referring to regard to down connect 1 and the description of joint tear edge), the minimum external dimensions 6 that the largest outer dimension 7 that this hose transition divides surpasses plastic tube end 4 reaches 2.5mm or 41% nearly.The effective external diameter of example of effective internal diameter of the example of plastic tube end 4 and plastic components end 5 6mm that respectively does for oneself.Because the alleviation structure 14 on the outer surface 8 of plastic components end 5, the maximum outside diameter 7 in this example increases to 8.5mm and/or about 41%.Plastic tube with unsteady size (greater or lesser diameter) can be obtained and respective redundant or the identical effect of undersize (undersizes) with plastic components.

Identical with previous drawings, Fig. 5 illustrates the axial partial cross section of the hose transition branch with pushing plastic tube.Compare the 4th embodiment that connects according to laser welding of the present invention, do not adopt here to keep hook 17 but form two periphery weldings that occur with sealing welded side seam form connecting 10.

Identical with previous drawings, Fig. 6 illustrates the axial partial cross section of the hose transition branch with pushing plastic tube.Compare the 4th embodiment that connects according to laser welding of the present invention, adopt here to keep hook 17 and will alleviate structure 14 separated into two parts.In fact alleviating structure 14 in conjunction with two keeps hook 17 to be connected 10 with three periphery weldings of sealing welded side seam form formation with wide end.

Identical with previous drawings, Fig. 7 illustrates the axial partial cross section of the hose transition branch with driving plastic tube.Compare the 6th embodiment that connects according to laser welding of the present invention, do not adopt here to keep hook 17, be divided into three parts, and connect 10 with three periphery weldings of sealing welded side seam form formation in conjunction with three alleviation structures 14 but will alleviate structure 14.If these three welded side seams are close enough each other, then three welded side seams can fuse each other, so form a wide especially welded side seam.

Identical with previous drawings, Fig. 8 illustrates the axial partial cross section of the hose transition branch with pushing plastic tube.Yet, in the 8th embodiment, that plastic tube 2 is configured to multilayer and comprise to the opaque internal layer 11 of laser.In plastic tube end 4, in connecting 1 first area 15, anticipation according to the present invention removes all, the intermediate layer that also has plastic tube 2 to the skin of laser substantially transparent, is in some cases leaned against on the plastic components end 5 and form welding area 10 when the laser welding with it to the opaque layer of laser.Internal layer 11 is preferably the ESD layer, and it electrically contacts closely with another plastic components 3 formation in the second area 16 of the connection 1 of anticipation.Form in the second area 16 on plastic components end 5 and keep hook 17 to improve ESD layer and electrically contacting that the conduction hose transition divides extraly.An embodiment shown in Figure 8 represents if the laser absorption internal layer is so thick and/or the major part that comprises the laser light absorber of high concentration like this so that laser energy in internal layer rather than be converted to the embodiment of heat with the contact point place of another plastic components 3.

Identical with previous drawings, Fig. 9 illustrates the axial partial cross section of the hose transition branch with pushing plastic tube.Yet in the 9th embodiment, plastic tube is embodied as bellows 19.Connect the smallest internal dimension of the largest outer dimension 7 of the inner end 5 in 1 zone greater than the outer end 4 of bellows 19 in this zone.The smallest internal dimension 6 that the largest outer dimension 7 that hose transition divides also preferably surpasses plastic tube end 4 is the percent value stipulated of front at least.Because this redundancy of largest outer dimension 7, contact pressure is formed between the both

ends

4,5, and this has strengthened mutual thermo-contact in the laser welding process.If bellows 19 is used for transmitting fluid (being liquid, steam or gas, for example fresh air), two weldings connect 10, and (or at least one of them) preferably is embodied as the periphery welded side seam.On the contrary, if bellows 19 does not for example need being tightly connected between plastic tube end 4 and the plastic components end 5 only as the protection tube of electric wire; In this case, the secure fixation of bellows 19 (preferably finishing in trough) is to use delegation's point type welding to finish, and the girth of bellows and/or insufficient each other several continuous short welded side seams are at least mainly followed in described point type welding.The outer surface 8 that release portion 14 is installed on plastic components 5 has also been strengthened connecting in 10 the process thermo-contact with bellows 19 in the preparation welding.

Compare the accompanying drawing that illustrates so far, Figure 10-Figure 12 illustrates plastic tube end 4 wherein and is pushed the axial partial cross section that the hose transition that is pressed into plastic components end 5 divides.In the tenth embodiment that uses the connection 1 that forms according to laser welding method of the present invention, plastic tube end 4 is pushed and is pressed into plastic components end 5, and interior plastic tube end 4 has and is embodied as opaque substantially at least one outer surface 12 of laser.On the contrary, plastic components end 5 at least the anticipation connection 1 the zone in to the laser substantially transparent.In the process of preparation welding area 10, plastic components end 5 therefrom sees through laser (zigzag arrow), the inner surface 13 that is subjected to the outer surface 12 of radiation and presses plastic components end 5 thereon up to plastic tube end 4 be heated and fusion till, thereby between radiant place plastic tube 2 and another plastic components 3, form welding area 10.

In the 11 optional embodiment (referring to Figure 11), at one end also comprising, plastic components end 5 keeps hook (periphery fin) 17.

In the 12 embodiment shown in Figure 12 (on its function corresponding to the tenth embodiment reverse), plastic components end 5 has inner surface 13, inner surface 13 comprises at least one the alleviation structure 14 that reduces inside dimension 6, form the contact pressure that increases thus during 4,5 assembling at both ends, this has further strengthened mutual thermo-contact in the laser welding process.Shown in the tenth embodiment that laser welding according to the present invention connects, like that, keep hook 17 to be formed at this (being formed in inside specifically).

About the redundancy and the undersize of the overlap joint diameter of two parts connected to one another, the preferable percent value identical with the embodiment with pushing pipe also is applicable to have the change example of inserting pipe.

The plastic tube end 4 and the plastic components end 5 of the cross section with revolution symmetry all are shown in institute's drawings attached.Therefore smallest internal dimension 6 is internal diameters and largest outer dimension 7 is external diameters.Yet, should pay special attention to pipe and not necessarily under every kind of situation, all have circular cross section.Therefore, also can envision olive shape, ellipse, triangle, rectangle, hexagon, octagon, arbitrary polygon, also have the swan-neck cross section different and can from prior art, know with circle.In addition, under special case, plastic components 3 also can be fixed on the near axis of plastic tube 2 or oblique with it.With reference to EP 1 705 050 A1, it is as an example of the non-circular pipeline of special hollow profile, and its center tap is not installed on the axis partly.

In the accompanying drawings, similar parts are marked by identical Reference numeral respectively, if not the words that under each situation all parts all are described in detail.Those skilled in that art know illustrated in and/or any combination of the embodiment that describes all fall within the scope of the invention.

The concrete chemical formula of the thermoplastic molded compound by the laser-transmitting welding can be known from European patent EP 1 240243 B1.As the replacement of single laser-light transparent pigment, at least two kinds of laser-light transparent pigment can be used for polymer matrix here, preferable with the appearance of complementary color form, it produces grey and/or dark impression to vision according to color theory.Therefore, (laser absorption) carbon black pigment can replace with the combination of two kinds of laser-light transparent pigment, if require dark and/or blackish color and luster impression in the article that machine.Then can in described laser welding method, use this class mold compound and other.

For the purpose of the present invention, the polyamide that those skilled in that art know, promptly homopolyamide, copolyamide and their mixture and admixture are preferably mainly as plastics and/or polymer.These polyamide can use the pigment coloring of laser-light transparent, so that the plastic tube of so making is from visually only different slightly or identical with the known plastic pipe.Extra additive, for example the inserts known of stabilizing agent (for example heat, hydrolysis and UV stabilizing agent), reinforcing agent (for example glass fibre) and those skilled in that art can be sneaked into the polymer mixed ingredients as required.Polyamide can be used for the layer of making by other polymer (for example with burning line in the barrier layer) multi-layer composition that constitutes.

The test example:

By having three fins and/or alleviating feature (situation A, B and the C of the standard pine nut profile of structure 14, referring to Fig. 7) with under the influence of media, have feature (the situation D of the hose transition spare of preferred alleviation structure with strong expansion effect, referring to Fig. 5) make comparisons, test the tight ness rating and the joint tear edge of connection 1.These four kinds of situations are as follows according to alleviating the difference of structure and mounting condition.

Table 1:

Situation	Alleviate structural joint	The mounting condition pipe
Situation	Alleviate structural joint	The mounting condition pipe	A	Pine nut profile (standard 1)	Pushing
B	Pine nut profile (standard 2)	Pushing	A	Pine nut profile (standard 1)	Pushing
B	Pine nut profile (standard 2)	Pushing	C	Pine nut profile (standard 1)	Pushing and laser welding
D	Preferred alleviation structure	Pushing and laser welding	C	Pine nut profile (standard 1)	Pushing and laser welding

In situation C, on all three fins, carry out laser welding (referring to Fig. 7).Situation C and D are according to embodiments of the invention.The individual layer laser-light transparent parts of the plastic tube of making by polyamide PA12 and strengthen another black plastic parts (joint) that absorb laser that the polyamide PA12 of structure and carbon black filler makes and be selected as the test exemplar by having 30% fibrous glass.

A joint and plastic tube parts are being installed and in situation C and D after the laser-transmitting welding under every kind of situation, the tubulose test exemplar that so obtains is filled up the E50-fuel combination, use chocking construction to seal in both sides, and 100 ℃ temperature with so be formed under the various steam pressures of testing in the exemplar and stored still 500 hours.Fuel mixture is made of E50 (50% ethanol), 5% water, 1% methyl alcohol and 44% unleaded Q-grade gasoline (all being volume % specification).Can use this fuel mixture to check quality of connection under the maximum conditions, this mixture is because its high ethanol content and have strong expansion effect on polyamide.

After fuel reservoir, according to the joint tear edge of SAE standard J2260 testing experiment exemplar (with plastic tube from the hose transition spare required power of tearing).Accepting tear edge according to the I of SAE standard J2044 and J2045 must be greater than 300N.By air being injected fixing underwater test exemplar and testing tight ness rating from visually setting up the effusion bubble.The pressure that is used for injecting air is 2 crust (overvoltage).And all tests are tested exemplar with corresponding (original) that is not stored in as yet in the fuel compare.In addition, the intensity of manual test joint connection.Draw following result.

Table 2

As the result of these tests, can announce that all original connections all meet the demands and not long term exposure in fuel.Yet, at first, make the tradition connection unclamp required tear edge and sharply descend making test exemplar long term exposure behind fuel with high ethanol content.Comparatively speaking, laser welding connects provides reliable connection always, even and in the sample long term exposure behind fuel, tear edge is within the specific limits still apparently higher than required limiting value.Even the fixing tear edge less than 300N as tolerable limit also is enough to unclamp tradition and connects (situation A and B), so these traditional jointings are regarded as when being connected the fuel that is used to have high ethanol content insecure.

In addition, the plastic tube that uses laser welding to be connected and fixed is immovably fixing, and promptly twistlock is on joint and/or hose connector.In fact, when attempting pipeline with welding and be pulled away from hose connector, will observe the fracture of plastic tube even connector.In order to obtain twistlock, what the traditional plug-in type by some laser point type weldings connected fixedly is enough.Yet, must apply higher tear edge and use the fixing plug-in type of welded side seam to connect to unclamp, therefore this connection is preferable.

Such as previously mentioned, owing to the test exemplar expansion that causes because of ethanol is particularly evident, the limiting strain that this test representative test connects.These results for example also can be diverted to other expansion fluid of biodiesel, oil, sugar alcohol or the pipeline of unexpansive fluid, to obtain higher bearer cap.Laser welding connection according to the present invention also can be used for typical occasion certainly, and has the advantage of bigger safety stock and tight ness rating raising.

Polyamide mainly is used as the plastics of plastic tube 2 and plastic components 3.Term " polyamide " is understood that homopolyamide, copolyamide and their mixture and admixture.The group that is made of the polyamide of aliphatic, cyclic aliphatic and partially aromatic (latter for example occurs with the form of polyphthalamide) is preferred, as this as those skilled in that art known like that (owing to the monomer as them, they depend on the type of selected polyamide and use).The polyamide of selecting from the group that comprises fatty polyamide PA 6, PA 610, PA 612, PA 11 and PA 12 and polyphthalamide is preferred for the mounting end 4 of plastic tube 2 and another plastic components 3.

The plastic tube 2 and the plastic components 3 that use such polyamide to make particularly are applicable to the burning line of making automotive, and described automotive for example is automobile, motorcycle, ship and aircraft.Laser welding method according to the present invention particularly is applicable to the plastic tube 2 and the plastic components 3 of the burning line that connects automotive, because these plastic tubes 2 and plastic components 3 often have complicated geometry (especially these pipes often are not that straight line is molded) and not removable or rotation in the laser welding process.Therefore, do not move the parts that will be fused if move laser beam according to the present invention, this is very favorable.

A kind of possibility is included in pipe and connects mobile lasing light emitter on every side.Yet, optics (lens, prism and/or mirror)---especially conical mirror---be used for making the laser beam that is used for welding to move and/or deflection around the fixing pipe that the mounting end 4 by plastic tube 2 and another plastic components 3 constitutes is connected.Therefore, only be laser beam, rather than lasing light emitter itself, connect mobile with respect to the pipe that will be fused.

Yet 1 the laser welding method according to the present invention of being connected that does not adopt axle to prepare plastic tube 2 and another plastic components 3 is particularly favourable.Therefore after finishing welding, save the removal axle.Especially when the connection plastic tube 2 of burning line and plastic components 3 are used for automotive, even do not damage pipe in most cases and just can't remove bearing core shaft.This be because, the space or the mounting condition that are provided in engine compartment and the fuel tank are provided, the burning line that this class is used for automotive often has the complex geometric shapes along two or three direction bendings that is suitable for being installed in the vehicles and is shaped and produces by for example heating.

Reference numerals list:

1 connects

2 plastic tubes

3 plastic components

The end of 4 plastic tubes, plastics pipe end

The end of 5 another plastic components, plastic components end

6 inside dimensions

7 external dimensions

85 outer surface

94 inner surface

10 welding areas

11 internal layers

12 4 outer surface

13 5 inner surface

14 alleviate structure

15 1 first area

16 1 second area

17 keep hook

18 chocking constructions

19 bellowss

Claims

1. laser welding method that is connected (1) that is used to prepare plastic tube (2) and another plastic components (3), wherein an end (4) of plastic tube (2) is installed with tubulated ends (5) overlap joint of another plastic components (3), each comfortable connection of described plastic tube end (4) and plastic components end (5) has inside dimension (6) or external dimensions (7) in (1) zone, and inner end (4,5) largest outer dimension (7) in connecting (1) zone is greater than outer end (5,4) smallest internal dimension in described zone (6), contact pressure thus and be formed on both ends (4,5) between, this has strengthened thermo-contact mutual in the laser welding process, it is characterized in that, the mounting end (4) of described plastic tube (2) and another plastic components (3) mainly is made of polyamide and does not use axle to fix, and the laser beam guiding that will be used for welding simultaneously is around fixing pipe joint.

2. laser welding method as claimed in claim 1 is characterized in that, uses optical element to guide laser beam around fixing pipe connects.

3. laser welding method as claimed in claim 1 or 2 is characterized in that, plastic tube end (4) and plastic components end (5) have the cross section of revolution symmetry, and its smallest internal dimension (6) is an external diameter for internal diameter maximum internal size (7).

4. as claim 1,2 or 3 described laser welding methods, it is characterized in that, go up in described plastic components end (5) and promote described plastic tube end (8).

5. laser welding method as claimed in claim 4, it is characterized in that, described plastic components inner end (5) has and is embodied as at least mainly to the opaque outer surface of laser (8), and described plastic tube end (4) at least in anticipation connects the zone of (1) mainly to laser-light transparent, described plastic tube end (4) therefrom sees through laser, up to the radiation outer surface (8) of plastic components end (5) with press the inner surface (9) of plastic tube end (4) thereon to be heated and fuse, therefore form welding area (10) between plastic tube (2) and another plastic components (3) at radiant.

6. laser welding method as claimed in claim 4, it is characterized in that, described plastic tube end (4) comprises and being embodied as at least in anticipation connects the zone of (1) the opaque substantially internal layer of laser (11), the thickness of described internal layer (11) is suitable for using laser, thereby described internal layer (11) is heated with the non-radiative outer surface (8) of plastic components end (5) and melts in case be subjected to radiation, so that the welding area (10) between plastic tube (2) and another plastic components (3) is formed at radiant.

7. as claim 5 or 6 described laser welding methods, it is characterized in that, that described plastic tube (2) is configured to multilayer and comprise to the opaque internal layer of laser (11), it is characterized in that, opaque all layers of laser are removed from plastic tube ends (4) that anticipation connects the first area (15) of (1), the lamination of laser substantially transparent are formed welding area (10) during to plastic components end (5) and at laser welding with it only to make plastic tube (2).

8. as claim 6 or 7 described laser welding methods, it is characterized in that described internal layer (11) is the ESD layer, described ESD layer is gone up or is being envisioned in the second area (16) that connects (1) in whole connection (1) and is electrically connected on another plastic components (3).

9. as claim 1,2 or 3 described laser welding methods, it is characterized in that described plastic tube end (4) is pushed into plastic components end (5).

10. laser welding method as claimed in claim 9, it is characterized in that, described plastic tube inner end (4) has and is embodied as at least one mainly to the opaque outer surface of laser (12), and described plastic components end (5) at least in anticipation connects the zone of (1) mainly to laser-light transparent, described plastic components end (5) therefrom sees through laser, up to the radiation outer surface (12) of described plastic tube end (4) with press the inner surface (13) of plastic components end (5) thereon to be heated and fuse, so the welding area (10) between plastic tube (2) and another plastic components (3) is formed at radiant.

11. the described laser welding method of any one in the claim as described above, it is characterized in that, described plastic components end (5) has inner surface (13) or the outer surface (8) that comprises at least one alleviation structure (14), described alleviation structure (14) reduces inside dimension (6) or increases external dimensions (7), form the contact pressure that increases thus when two ends 4,5 are installed, this has further strengthened the mutual thermo-contact in the laser welding process.

12. the described laser welding method of any one in the claim is characterized in that as described above, the girth along two mounting ends (4,5) forms a plurality of point-like welding area (10) and/or non-periphery welded side seam substantially.

13. as any one described laser welding method of claim 1-11, it is characterized in that, between plastic tube (2) and another plastic components (3), form at least one periphery welding area (10) along two mounting ends (4,5) substantially.

14. laser welding method as claimed in claim 11 is characterized in that, multiple spot welding area (10) and/or non-periphery welded side seam or at least one periphery welding area (10) are positioned on the alleviation structure (14) of another plastic components (3).

15. the described laser welding method of any one in the claim is characterized in that as described above, described largest outer dimension (7) surpasses described smallest internal dimension (6) at least 1%, preferably surpasses 5%, and is outstanding goodly above 10%.

16., it is characterized in that described largest outer dimension (7) surpasses described smallest internal dimension (6) 15%-70% as claim 14 or 15 described laser welding methods, nearly preferably surpass 41%.

17. laser welding method as claimed in claim 12 is characterized in that, except that point-like welding area and/or non-periphery welded side seam, preferably will be used for the overlap of plastic tube end (4) and plastic components end (5) with the rubber seal that O shape loop type occurs.

18. the described laser welding method of any one in the claim as described above, it is characterized in that the polyamide of the mounting end (4) of described plastic tube (2) and another plastic components (3) is to select from the group that is made of aliphatic, cyclic aliphatic and partially aromatic.

19. laser welding method as claimed in claim 18, it is characterized in that the polyamide of the mounting end (4) of described plastic tube (2) and another plastic components (3) is to select from the group of fatty polyamide PA 6, PA 610, PA 612, PA 11 and PA 12 and polyphthalamide formation.

20. use any one described laser welding method in the claim as described above to connect the plastic tube (2) and the plastic components (3) of the burning line of automotive.