Method for joining two plastic parts materially, joining two plastic parts, liquid-carrying housing, modular pump-valve unit and heat transfer medium circuit system

Abstract

A method for joining two plastic parts (4, 6) is proposed, in which a first impact area (8) of a first plastic part (4) and a second impact area (8, 10) of a second plastic part (6) are brought into a viscous state under the influence of a laser beam (L1, L2) before joining the two plastic parts, wherein the two plastic parts are then joined together via these two impact areas to form a material-locking joint. In this arrangement, at least one of the two plastic parts (4) is provided with a shaped protective leg (S, 12, 14) projecting beyond the associated impact area (8) in a thrust direction (X - X), through which a weld seam (16) driven out when the two plastic parts (4, 6) are overlapped in a longitudinal extent (X - X) of the generated material-jointed plastic part connection (2) and in the thrust direction, thereby limiting the elongation of the weld seam. Furthermore, a plastic component connection, a fluid-carrying housing, a modular pump-valve unit and a heat transfer medium circuit system are proposed.

Description

[0001] The invention relates to a method for the material-to-material joining of two plastic parts, a connection of two plastic parts which are joined by this method, a liquid-conducting housing, a modular pump-valve unit for a heat transfer medium circuit (circuit) system, in particular of a motor vehicle or vehicle, and a heat transfer medium circuit (circuit) system with such a liquid-conducting housing and / or such a modular pump-valve unit.

[0002] Plastic parts are used in a wide variety of technical fields, such as the automotive industry. Plastic parts can be bonded together in a variety of ways.

[0003] The object of the present invention is to provide an improved plastic part connection of this type.

[0004] This object is achieved by a method proposed and protected according to claim 1.

[0005] A method for the material-to-material joining of two plastic parts is proposed, in which a first joint region of a first plastic part and a second joint region of a second plastic part are liquefied or brought into a molten state under the influence of a laser beam before these two plastic parts are joined.

[0006] The term 'liquefied' or 'molten state' means that the two joint areas are converted or brought into a viscous or viscous state by the action of the laser beam, which as such enables a material bond in the form of a material-to-material joint between the two plastic parts.

[0007] These two plastic parts are then joined together across these two butt areas, forming a material-to-material joint. This means that these two plastic parts are joined together and butted against each other across these two butt areas. This creates a material-to-material connection between the two plastic parts, and a weld seam is created between the two plastic parts.

[0008] In this case, at least one of the two plastic parts is provided with a shaped protective leg which projects beyond the associated joint area in a joint direction, by means of which the weld seam produced during the jointing or joint formation of the two plastic parts overlaps in a longitudinal extent of the produced material-locking plastic part connection and in the joint direction, and in the process a lateral expulsion of the weld seam, ie transverse to the joint direction, is geometrically limited.

[0009] "Transverse" refers to a weld seam extrusion direction that is orthogonal to the joint or the joint area or the longitudinal extension of the plastic part connection or the joint direction. However, this weld seam extrusion direction can also form or enclose an obtuse or acute angle with the said longitudinal extension of the plastic part connection or the said joint direction.

[0010] The liquefied joint areas represent local melting areas—also called melt pools. These melting areas are advantageously monitored using a thermal imaging camera to ensure that the melting areas are neither too cold nor too warm. This ensures a high-quality bond.

[0011] And by overlapping this weld seam, this protective leg shields it from an environment that acts on the weld seam and causes weld seam particles to detach. In a fluid-conducting plastic housing, which as such is composed of at least two plastic parts that define or form a plastic part connection of the type described above at their joints, this type of plastic part connection protects the weld seam from a fluid acting on it, in particular a fluid subjected to increased pressure, so that the aforementioned detachment of weld seam particles is advantageously counteracted. Fluid-induced detachment of weld seam particles is advantageously prevented. The protective leg thus describes a type of joint protection (geometry) to protect the weld seam.

[0012] Such weld particles can cause damage to components such as pumps or valves in a heat transfer fluid circuit. The plastic part joint produced using the proposed process minimizes the risk of such damage.

[0013] The plastic parts are made of a glass-fiber-reinforced thermoplastic. Examples of suitable plastics and plastic types include PA GF 0-60%, PBT GF 0-60%, PPA GF 0-60%, PP GF 0-60%, PC / ABS GF 0-60%, POM GF 0-60%, and PPS GF 0-60%. These plastics directly absorb laser beams, allowing the laser beam to penetrate a few tenths of a millimeter—approximately 0.2 mm—to locally liquefy them.

[0014] In contrast to a joining process, such as that described in US Pat. No. 5,893,959 A, which requires two different materials for a material-to-material bond between two plastic parts, one of which must be transparent and the other absorbent, the proposed process is independent of a temporal change in the crystallinity of a transparent plastic part (aging phenomenon) due to aging. Furthermore, it is independent of the transparency of the plastic part, which is influenced by a so-called flow path direction. Furthermore, it is independent of glass fiber content, which, as such, influences such plastic part transparency.

[0015] In contrast to the document US 5893959 A, the proposed process also allows for greater melting depths. This enables better compensation of component deviations or inaccuracies (reduction of a tolerance chain).

[0016] In addition, according to the proposed method, in contrast to the document US 5893959 A, unevenness of a joining surface has a significantly smaller influence on the resulting joint.

[0017] By avoiding all these disturbing influences, the proposed method provides a better weld seam formation or material bond in contrast to the document US 5893959 A.

[0018] Such plastics, when using a laser, such as a diode laser as a heat source or laser beam source, allow the treatment of very small or very finely defined joint areas using a finely adjusted or measured laser beam. This achieves shallow penetration depths of a few tenths of a millimeter in these plastics, for example, penetration depths of approximately 0.2 mm. Thus, the proposed method advantageously allows the formation of very small or very finely defined melting areas, also called melt pools, which, as such, have a low melt volume.

[0019] In one embodiment, two plastic parts that are at least substantially identical in terms of their joining sections and asymmetrical in cross-section are provided, each with a molded protective leg that extends beyond the associated joint area. During joining, the two plastic parts complement each other in such a way that the extruded weld seam overlaps one of the protective legs on each side of the resulting material-to-material connection, thereby geometrically limiting the extrusion of the weld seam.

[0020] In a further embodiment, two plastic parts are provided which together form a tongue-and-groove-like joint protection or a tongue-and-groove-like joint protection geometry to protect the weld seam with respect to their joining sections in the joined state. In this case, a first butt area is provided in a groove of the first plastic part in an area of ​​a groove base, and a second butt area is provided on a tongue of the second plastic part in an area of ​​a free end of the tongue, each of which is liquefied under the influence of the laser beam. The tongue is then inserted into the groove to form the material-to-material joint, with the weld seam thus expelled being expelled within the groove and overlapped by the two groove walls. Expulsion of the weld seam is geometrically limited by the two groove walls.

[0021] In one embodiment, the weld seam is driven out in such a way that a gap is formed between the weld seam and the associated protective leg or the groove walls.

[0022] In a further embodiment, the weld seam is driven out in such a way that it contacts the associated protective leg or the groove walls, but does not form a material bond.

[0023] This provides a kind of support for the weld seam. Furthermore, the shielding of the weld seam is improved, especially against a liquid that is subjected to increased pressure and at least partially surrounds the weld seam.

[0024] In an alternative embodiment, when the laser beam acts on the plastic part with the protective leg or the groove, the protective leg or at least one of the groove walls is also liquefied in some areas and on the butt side. During the butt jointing or butt formation of the two plastic parts, the weld seam is extruded in such a way that it also forms a material bond with the protective leg or with the at least one groove wall. In this embodiment, the material bond thus encompasses not only the first and second butt areas, but also a region of the at least one protective leg or the at least one groove wall. This provides the weld seam with even better support. In addition, the aforementioned shielding of the weld seam is improved even further.

[0025] The first and / or the second butt area can be provided on a projection section - in the sense of a welding rib - of the associated plastic part and at a free end of the projection section.

[0026] The protective leg or at least one of the two groove walls can be chamfered on the butt side in the area of ​​its free end in order to facilitate or support the joining of the two plastic parts.

[0027] Furthermore, a connection between two plastic parts is proposed, which together form a type of joint protection or a joint protection geometry for protecting a weld seam with respect to their joining sections in the joined state. The two plastic parts are joined together using the method described above (claim 9).

[0028] Furthermore, a liquid-conducting plastic housing is proposed with individual plastic housing parts forming the housing, which form a connection of the type described above with a joining protection or a joining protection geometry at the mutually facing and interconnected joining sections (claim 10).

[0029] Furthermore, a pump-valve unit for conveying and distributing a cooling fluid within a heat transfer medium circuit (circuit) system, in particular of a motor vehicle, is proposed. The pump-valve unit comprises a fluid-conducting plastic housing of the type described above (claim 11).

[0030] The individual housing parts forming the housing are designed as cassette modules, which are complementary to one another at the facing and interconnected joining sections, thereby forming a connection of the type described above with a joint protection or a joint protection geometry. The joined housing parts form fluid-carrying channels, with the housing having several inlet and outlet openings on both the suction and pressure sides.

[0031] In addition, a heat transport medium circuit system with a liquid-conducting plastic housing of the type described above and / or a pump-valve unit of the type described above is proposed (claim 12).

[0032] The invention will be explained in detail below with reference to the accompanying drawings. Further advantageous developments of the invention will become apparent from the dependent claims and the following description of preferred embodiments. These are shown, partly schematically: Fig. 1 two plastic parts to be joined and bonded together, as well as a bonded connection between these two plastic parts, Fig. 2 treatment of the plastic parts with a laser beam, Fig. 3 alternative joining geometries, Fig. 4 another alternative joining geometry, Fig. 5 another alternative joining geometry, Fig. 6 a modular pump-valve unit with such plastic connections, Fig. 7 an exploded view of the Fig. 6 shown multi-part housing of the pump-valve unit and Fig. 8 a central housing module of the Fig. 6 and Fig. 7 shown housing.

[0033] Fig. Figure 1 illustrates various variants Var 1, Var 2, Var 3 of joining pairs, each comprising a first plastic part 4 and a second plastic part 6. These plastic parts 4, 6 are joined together and thereby bonded together to form a plastic part connection 2.

[0034] In the joined state, all of these plastic parts 4, 6 form a type of joint protection (geometry) through which a weld seam 16 produced during the butting or joint formation of the two plastic parts 4, 6 overlaps and is thus shielded and protected from an environment that acts on the weld seam.

[0035] While the plastic part 4 is formed with a groove N, the plastic part 6 is formed with a spring F to be inserted into the groove N.

[0036] In variants Var 1 and Var 3, a projection (section) V - in the sense of a welding rib - is formed in a groove base NG, which extends in the direction of the open end of the groove N and forms a first butt area 8 at its free end. In Var 2, however, the groove base NG itself forms the first butt area 8. In variant Var 3, the two groove walls 12, 14 are also chamfered at their open ends on the inside and butt side, so that the opposing chamfers widen the groove N in some areas and thus support or facilitate the joining of the two plastic parts 4, 6. The spring F forms the second butt area 10 at its free end.

[0037] The Fig. The plastic part connection 2 shown in Figure 1 - on the far right - is characterized by the fact that it shields and thus protects the weld seam 16 produced during the joining and butting of the two plastic parts 4, 6 from the environment. This weld seam 16 is formed within the groove N and in the area of ​​the groove base NG.

[0038] The Fig. The arrows shown in Figure 1 illustrate an axial stroke to be performed between the two plastic parts 4, 6 relative to each other in order to join the two plastic parts 4, 6 together and thereby bond them together. This axial stroke can be executed or effected via the plastic part 4 and / or the plastic part 6.

[0039] The Fig. Figure 2 illustrates the treatment of two further variants Var 4, Var 5 of joining pairs using a laser beam as a heat source. While in the left illustration of Fig. 2 a laser beam L1 acts only briefly on the projection (section) V - in the sense of a welding rib - of the plastic part 4 and thereby liquefies the first joint area 8, a laser beam L2 acts briefly on the free end of the spring F of the second plastic part 6 and thereby liquefies the second joint area 10.

[0040] The variant Var 4 describes a joining geometry in which only the groove wall 12 is chamfered on the inside or on the tongue side or on the butt side in order to support or facilitate the joining of the two plastic parts 4, 6.

[0041] When the two plastic parts 4, 6 are butted or joined, the resulting - only in the Fig. 1 - can be driven out laterally in such a way that a gap is formed between the weld seam 16 and the groove wall 12, 14. Alternatively, the weld seam 16 can be driven out in such a way that it contacts the groove walls 12, 14, but does not form a material bond with them.

[0042] In the right-hand illustration of Fig. 2, however, the laser beam L1 is dimensioned such that it irradiates not only the projection (section) or the welding rib V, but also the groove base NG as well as the two groove walls 12, 14 in certain areas and on the inside, tongue side, or butt side. This allows a materially bonded joint to be formed which, in addition to the two butt areas 8, 10, also partially encompasses the two groove walls 12, 14. This means that when the two plastic parts 4, 6 are joined and butted, the weld seam 16 is driven out in such a way that it also forms a material bond with the two groove walls 12, 14.

[0043] Such a material connection is in the Fig. 1 (extreme right) illustrates this.

[0044] The variant Var 5 also describes a joining geometry in which only the groove wall 12 is chamfered on the inside or on the tongue side or on the butt side in order to support or facilitate the joining of the two plastic parts 4, 6.

[0045] For the treatment or liquefaction of the joint areas 8, 10, a single laser or a single laser beam source, such as a diode laser, is generally sufficient. Using such a laser beam source, the first plastic part 4 and then the second plastic part 6, or vice versa, can be briefly irradiated, thus preparing them for joining and butting (or joint formation). Fig. 2, however, two laser beams L1, L2 - of an associated laser or an associated laser beam source - are shown, which as such advantageously enable a simultaneous treatment or liquefaction of the two impact areas 8, 10.

[0046] The Fig. 3 illustrates further variants of joining pairs, whose respective plastic part 4 has only one protective leg S overlapping the weld seam 16. This protective leg S is expediently provided on a liquid-conducting plastic housing side in order to shield and thus protect the weld seam 16 from a liquid.

[0047] The variants Var 6, Var 7 and Var 8 differ from the variants Var 9, Var 10, Var 11 only by a shaped profile - in the form of lateral projections - on the side of the respective joining pair facing away from the protective leg S.

[0048] Also those in the Fig. The arrows shown in Figure 3 illustrate an axial stroke to be performed between the two plastic parts 4, 6 relative to each other in order to join the two plastic parts 4, 6 together and thereby connect them in a materially bonded manner.

[0049] The Fig. Figure 4 illustrates an advantageous variant Var 12, in which the plastic part 4 has less or as little mass as possible along a longitudinal extension X - X of the plastic part connection 2. This prevents the formation of vacuoles—i.e., material inhomogeneities in the form of vacuum bubbles—in the plastic used as a result of injection-molded production of the plastic part 4.

[0050] The Fig. The chamfers shown in Figures 1 to 4 support or facilitate the joining of the two plastic parts 4, 6 if the two plastic parts 4, 6 are not optimally aligned with each other.

[0051] The Fig. 5 illustrates a variant Var 13 of a joining pair, in which two plastic parts 4 that are identical in terms of their joining sections are combined with one another. These joining sections are asymmetrical when viewed in cross-section and are each formed with a protective leg S, wherein the protective leg S projects beyond a projection (section) V—in the sense of a welding rib—of an associated plastic part 4 or projects beyond the projection (section) V, which as such forms a joint region 8 at its free end.

[0052] Alternatively, two plastic parts 4 could also be combined with each other, the joining sections of which are essentially the same shape or differ only slightly or hardly at all from each other, for example by saving or omitting a projection (section) or a welding rib V on one of the two plastic parts 4.

[0053] The two protective legs S shield the weld seam (not shown here) from the environment when the two plastic parts 4 are joined and materially butted.

[0054] The Fig. Figure 6 illustrates a modular pump-valve unit (PVE) for pumping and distributing a cooling fluid—for example, in the form of a water-glycol mixture—within a heat transfer medium circuit (circuit) system, particularly in a motor vehicle. The pump-valve unit (PVE) comprises several pumps and valves.

[0055] A liquid-carrying plastic housing of the pump-valve unit PVE is made up of individual housing parts G that form the housing. Z, G1, G2, G3, G4 are formed in the form of cassette modules, which are complementary to one another on the mutually facing and interconnected side or joining sections, thereby forming a connection of the type described above with a joining protection or a joining protection geometry. The joined housing parts G Z , G1, G2, G3, G4 liquid-carrying channels (out), whereby the housing has several inlet openings and outlet openings on the suction side and pressure side.

[0056] The Fig. 8 illustrates a central housing part or cassette module G Z , in which several - however not fully shown - multi-way valves are provided or accommodated and which is provided with a first and second housing part or cassette module G1, G2 (see Fig. 6 and Fig. 7) and forms a plurality of first and second liquid-conducting channels with the first and second housing parts or cassette modules G1, G2.

[0057] The Fig. 8 visible cylindrical cavities of the cassette module G Z form the valves, whereby one must imagine essentially cylindrically shaped valve actuators that can be adjusted electrically or by an electric motor in these cavities.

[0058] All of the plastic parts and plastic housing parts described above are made of a glass-fiber-reinforced thermoplastic, such as PP GF 30%, which, as such, can be advantageously treated, irradiated, or liquefied in conjunction with a laser, such as a diode laser, as described above. These plastic parts and plastic housing parts are understood to be directly absorbent with respect to a laser beam acting upon them.

[0059] The previously mentioned diode laser is just one example of a laser beam source. Alternatively, fiber lasers or disk lasers are also suitable as laser beam sources.

[0060] It is proposed to use such a laser beam source in the sense of an IR source (IR = infrared). This is because the IR spectrum is suitable for the targeted irradiation of the aforementioned joint areas. Only a laser beam source of this type makes it possible to treat very finely formed or shaped joining sections of joining pairs of the type described above using the proposed method, in order to subsequently bond them together as described above. Using a wavelength – in this case, the IR spectrum – a penetration depth into such a plastic part can be precisely determined.

[0061] Although exemplary embodiments are explained in the foregoing description, it should be noted that numerous modifications are possible. Furthermore, it should be noted that the exemplary embodiments are merely examples and are not intended to limit the scope of protection, applications, or structure in any way. Rather, the foregoing description provides the skilled person with a guide for implementing at least one exemplary embodiment, whereby various modifications, particularly with regard to the function and arrangement of the described components, can be made without departing from the scope of protection as it results from the claims and equivalent combinations of features. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 5893959 A [0014, 0015, 0016, 0017]

Claims

[1] Method for the integral joining of two plastic parts (4, 6), in which a first butt area (8) of a first plastic part (4) and a second butt area (8, 10) of a second plastic part (6) are brought into a molten state under the action of a laser beam (L1, L2) before the two plastic parts (4, 6) are joined, each of which is a plastic part (4, 6) which directly absorbs a laser beam, the two plastic parts (4, 6) then being joined to one another via these two butt areas (8, 10) to form a integral joint, at least one of the two plastic parts (4) being provided with a shaped protective leg (S, 12, 14) which projects in a joint direction (X - X) beyond the associated butt area (8), by means of which a protective leg which is formed when the two plastic parts (4,6) the expelled weld seam (16) is overlapped in a longitudinal extension (X - X) of the produced material-to-material plastic part connection (2) and in the butt direction (X - X), thereby limiting the expulsion of the weld seam (16). [2] Method according to claim 1, wherein two plastic parts (4) which are at least substantially identical with respect to their joining sections and asymmetrical in the cross section of the joining sections are provided, each with a shaped protective leg (S) projecting beyond the associated joint region (8), wherein the two plastic parts (4) complement each other during joining in such a way that the expelled weld seam (16) in the longitudinal extent (X - X) of the produced material-to-material connection of the plastic parts (2) overlaps on both sides of one of the protective legs (S) in each case and in the process an expulsion of the weld seam (16) is limited. [3] Method according to claim 1, wherein two plastic parts (4, 6) are provided, which together form a tongue-and-groove-like joint protection geometry for protecting the weld seam (16) with respect to their joining sections in the joined state, wherein on the one hand a first butt area (8) is provided in a groove (N) of the first plastic part (4) in a region of a groove base (NG) and on the other hand a second butt area (10) is provided on a tongue (F) of the second plastic part (6) in a region of a free end of the tongue (F), which are each liquefied under the action of the laser (L1, L2), wherein the tongue (F) is subsequently introduced into the groove (N) to form the material-to-material joint, wherein the weld seam (16) thus expelled is expelled within the groove (N) and overlapped by the two groove walls (12, 14), wherein an expulsion of the weld seam (16) by the two Groove walls (12, 14). [4] Method according to one of the preceding claims, wherein the weld seam (16) is driven out in such a way that a gap is formed between the weld seam (16) and the associated protective leg (S) or the groove walls (12, 14). [5] Method according to one of the preceding claims 1 to 3, wherein the weld seam (16) is driven out in such a way that it contacts the associated protective leg (S) or the groove walls (12, 14), but does not form a material bond. [6] Method according to one of the preceding claims 1 to 3, wherein when the laser beam (L1, L2) acts on the plastic part with the protective leg (S) or the groove (N), the protective leg (S) or at least one of the two groove walls (12, 14) is also brought into a molten state in regions and on the butt side, wherein when the two plastic parts (4, 6) are butted, the weld seam (16) is driven out in such a way that it also forms a material bond with the protective leg (S) or with the at least one groove wall (12, 14). [7] Method according to one of the preceding claims, wherein the first and / or the second abutment region (8, 10) is / are provided on a projection portion (V) of the associated plastic part (4, 6) and thereby at a free end of the projection portion (V). [8] Method according to one of the preceding claims, wherein the protective leg (S) or at least one of the two groove walls (12, 14) is chamfered on the butt side in the region of its free end. [9] Connection (2) of two plastic parts (4, 6) which together form a joint protection geometry for protecting a weld seam with respect to their joining sections in the joined state, wherein the two plastic parts (4, 6) are connected to one another by the method according to one of the preceding claims. [10] Liquid-conducting plastic housing with individual plastic housing parts forming the housing, which form a connection according to claim 9 at the mutually facing and interconnected joining sections. [11] Pump-valve unit (PVE) for conveying and distributing a cooling liquid within a heat transfer medium circuit (circuit) system, in particular of a motor vehicle, with a liquid-conducting plastic housing according to claim 10, wherein individual housing parts forming the housing (G Z , G1, G2, G3, G4) are formed in the form of cassette modules, which form a connection according to claim 9 at the mutually facing and interconnected joining sections, wherein the joined housing parts (G Z , G1, G2, G3, G4) form liquid-carrying channels, whereby the housing has several inlet openings and outlet openings on the suction side and the pressure side. [12] Heat transfer medium circuit system with a liquid-conducting plastic housing according to claim 10 and / or a pump-valve unit (PVE) according to claim 11.

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