DE102017120503A1 - An injection molding tool and method of making an injection molded manifold for a heat exchanger - Google Patents

Abstract

Injection molding tool for producing a collecting tube with connecting lugs, with two forms forming a cavity, wherein two from opposite sides in the cavity retractable and engageable with each other and held by a force in cores are provided, forming against a melt through the interiors of the connection lugs Core pins are supported, and sprue points whose position is chosen so that the force with which the cores are held in abutment, is not reduced by the melt during the injection of the melt into the cavity.

Description

With the present disclosure, a compact injection molding tool and a method of manufacturing an injection molded manifold for a heat exchanger and such an injection molded manifold are provided. The manifold is adapted to be used as part of a heat exchanger system in buildings.

Building heat exchangers are increasingly being integrated into ceilings, floors and walls to increase living comfort and reduce the flow temperature required. Modular trained and thus adaptable to any spatial forms surface and integrable in the wall, floor or ceiling, such as plasterable heat exchangers are formed by two parallel manifolds through a plurality of connecting pipes, which extend perpendicular to the headers, are flowed diagonally.

Simple plastic pipes are usually (endlessly) extruded in the prior art. By means of this technique, however, only components can be produced which have a cross-section that is constant with respect to the longitudinal direction. Plastic pipes with non-uniform cross-section, such as manifolds for the above-mentioned heat exchangers, in particular from a length of more than 30 cm, are usually injection-molded in a half-shell process. For this purpose, a lower shell of the later pipe is injection-molded in a first step and injection-molded in a second step, an upper shell of the later pipe. In a third step, both half-shells are connected to each other.

Since both the joining of the half-shells to each other to form a collecting pipe and the collecting pipes formed of the half-shells to each other by gluing or welding is susceptible to leaks, there is a need for an apparatus and a method for producing headers and manifolds themselves, in which leaks be avoided.

This object is achieved with a tool according to claim 1, a method according to claim 10 and a manifold according to claim 12. Further developments are specified in the dependent claims.

Claim 1 specifies a compact injection molding tool with which, in cooperation with an injection unit, a collecting pipe made of plastic, which can preferably be used in a heat exchanger, is produced. With the injection unit of the respective material (base material) is liquefied and injected into the injection mold with high pressure. As an injection unit, for example, a screw plunger unit which is usual today is used, so that detailed description thereof is omitted here.

With the specified injection molding tool headers can be easily produced with a length of preferably greater than 500mm to preferably 2000 mm with a minimum wall thickness of preferably 1.5mm to 4mm. The inner diameter of the headers is preferably between 8 mm and 30 mm. The inner diameter is preferably constant or formed with a small conicity in the longitudinal direction of the tube. The conicity is achieved, for example, by an inner diameter which is enlarged by approximately 0.3 mm with respect to the center of the collecting tube at the ends of the collecting tube.

The manifold thus produced itself is integral, i. formed in one piece and in only one step, so that the Sammelroh itself does not have the tightness problems known from half shells. Due to the large length of the manifold, a reduction in the number of steps to build the heat exchanger is possible. Next, the number of manifolds and thus the number of connections between manifolds is reduced, so that again a reduction of possible leaks at connection points of individual manifolds such heat exchanger is achieved. At the same time, the manifold has a relatively small wall thickness and a relatively small inner diameter to meet the requirements for good heat transfer and good flow.

It has been found that two advantages can be achieved by the use of two cores that can be moved into the cavity in opposite directions: on the one hand, the respective force with which each core is pulled out of the tool after the melt has hardened before the mold means are opened must be significantly reduced (essentially halved) compared to a corresponding tool with only one, but twice as long core. On the other hand, the possible diameters and wall thicknesses of the cores, and thus their pull-out strength (which depends on the cross-sectional area), when using conical cores with the same maximum manifold inner diameter (which is determined from the largest core outer diameter) significantly increased compared to a corresponding tool with only one, but twice as long core. This is especially the case with the use of hollow cores.

By forming the (lengths of) cores such that one or both ends of the cores come in contact with a core pin, the interconnected ends when feeding the melt again improved supported by the corresponding core pin against a perpendicular to the longitudinal direction deformation. Thus, in the case of an even number of connecting lugs, the cores are preferably asymmetrical, ie of unequal length, while they may be symmetrical, ie of the same length, if the number of connecting lugs is an odd number.

By forming at least one gate point per core such that it opens into the cavity on the side opposite the core pins, it is achieved that only a force is applied by the melt in one direction to the respective core, which is in the plane of the core pins or of the core itself and has at least one component in the direction of the core pins. The cores are therefore supported against the force applied by the injected melt through the core pins, so that bending is prevented. At the same time, the force applied to the cores by the supplied melt leads to an increase in the contact pressure of the cores with the core pins, so that a gapless contact of the core pins on the cores is achieved. In this way it can be ensured that the interiors of the connection noses formed with the melt are continuously connected to the collecting tube interior. A post-processing, for example, to pierce a plastic film, which can form between the core and core pin, when the core pin is not tight, can be avoided.

Usually, the gate points are arranged and designed such that the melt is injected in and against the longitudinal direction starting from the gate point. The starting points and the other parameters of the melt supply are preferably designed such that the one or more starting points formed in the region of the first core also supply only melt which also forms the corresponding section of the collecting tube in the region of the first core. In other words, the melt supplied in the region of the first core preferably connects to the melt supplied in the region of the second core approximately in the region of the contact points of the cores. In the case of an elongated cavity, therefore, it is usually injected in the middle of the corresponding area to reduce the path the melt has to travel to fill the cavity, whereby the flow behavior etc. is ultimately improved. If the path is too long, the melt may cool before reaching the endpoints, i. before completely filling the cavity. For multiple gate points, the distance between the gate points should be such that the melt of one gate point can bond to the melt of the other gate point to form an integral body. For this, it must be ensured that the melt at the point of contact with the other melt has not yet set.

Contrary to the usual central design of the sprue points, it has been found to be particularly advantageous not to arrange the sprue points centrally with respect to the area to be filled by them, but with reference to the center of the cavity in the longitudinal direction further outwards. By such positioning of the gating points such that each core during feeding from the melt through the melt pressed into and into the cavity longitudinally and in the longitudinal direction exclusively toward the other core or at least not away from it is pressed, it is ensured that the cores are not separated even during and after the injection of the melts. In other words: starting at one end in the longitudinal direction Z the cavity 22 with a total length L1 For example, the first gate point is preferably located at a position X1 1/8 × L1 <X1 <1/4 × L1, and the second gate point is preferably at a position X2 3/4 × L1 <X2 <7/8 × L1.

The same effect, in particular if more than two gate points per core are provided, can also be achieved by specifying the size and thus the volume flow through the respective gate point. For example, a greater volume flow through the outer gate also ultimately results in a force towards the other core.

Due to the complementary conical design of the mutually facing ends of the cores a self-centering and safe and low-density sealing compound of the cores is achieved.

Due to the hollow design of the cores is a cooling channel for cooling the core, preferably with compressed air available. Preferably, the cooling device is designed such that in the state in which both cores are sealingly connected, a compressed air flow through both cores, and in the state in which both cores are not connected to each other, for example in the extended state, the cores of each its own compressed air flow is flowed through in opposite directions. This enables efficient cooling and thus higher cycle time and improved quality.

By combining the above-mentioned features can be a particularly long manifold with integrally formed connection lugs economically produce, in which no joints are available and thus possible leaks are not only avoided but excluded.

By keeping the cores pressed together by means of at least one spring, deformation or compression of the cores or of the rest of the tool can be prevented from occurring as the cores expand. At the same time, it ensures that the force with which the cores are pressed against one another is maintained in order to prevent the melt from penetrating between the cores.

To further improve the flow behavior of the melt and / or the cycle time, several, for example, two starting points per core can be provided. It must be ensured that the sum of the forces acting on the respective core through the melt during the injection of the same result in a force in the direction of the other core, at least not leading to a force in the direction away from the other core. Preferably, a force is continuously generated in the direction of the other core during the feeding of the melt by means of the same. In particular, should not result in any state by the melt an opposite force on the respective core.

Even if there are several sprue points per core, it must be ensured by the arrangement of the cores that the respective partial flows of the melt connect well. In order to achieve the stated objectives (no force on cores in the direction of each other, good fusion bonding), both the position and the size of the gate points or the sprue passages supplying the gate points must be taken into account and designed.

Optionally, the collecting tube has reinforcing ribs in the longitudinal direction and / or in the transverse direction.

Instead of using cores having a conical second section, cores without conicity, i. Cores, which have a constant cross section perpendicular to the longitudinal direction, are used.

To improve the sealing in conjunction of the two cores, an O-ring o. Ä. be provided in the terminal extension or the connection receptacle. Furthermore, the connection extension and the connection receptacle are preferably adapted to one another in such a way that the cores in the connected (retracted) state abut each other without transition. This ensures that the channel formed in the interior of the collecting tube is formed in the longitudinal direction continuously with a constant diameter.

To improve the cooling of the cores, the compressed air supplied is preferably cooled. For this purpose, for example, a vortex tube, with the conventional compressed air is split into a cool and a warm compressed air stream can be used.

Preferably, the switching between common cooling of the cores takes place (in the retracted state) starting from only one end of one of the cores and the cooling, in which both cores are cooled starting from their respective outer ends, by a 3/2 way valve.

To reduce the cycle time, limit switches are preferably provided for the core end positions (retracted and extended).

To reduce the friction between the second molding 12 and the cores may be the second molding 12 alternatively already be opened before the extension of the cores.

To assist the ejection of the manifold after the solidification of the melt and opening the tool, an ejector may be provided. Usually, such ejection device consists of ejector pins provided in the first molded part which can be retracted from below into the cavity and push the collector tube out of the first molded part without damage.

The manifold is made of PE, for example. For example, the material SABIC Vestolen P 9421 is used.

The tool may be configured such that only a single continuous cavity is formed to form a single manifold through the mold members, or multiple (separate) cavities are formed to simultaneously form multiple manifolds through the two mold members. In the case of several cavities, a corresponding number of slide devices (at least one per cavity), gate points (at least two per cavity) and cores (two per cavity) are also provided. The Kernzuführvorrichtungen can also feed several cores at several cavities simultaneously. Alternatively, a separate Kernzuführvorrichtung may be provided for each core.

• 1 eine skizzenhafte perspektivische Ansicht eines beispielhaften Spritzgusswerkzeugs in geöffneter Position gemäß einer ersten Ausführungsform,
• 2 eine Aufsicht auf das Spritgusswerkzeug gemäß der ersten Ausführungsform,
• 3 eine Querschnittsansicht des teilweise geschlossenen Spritgusswerkzeugs gemäß der ersten Ausführungsform,
• 4 in a) einen beispielhaften skizzenhaft dargestellten ersten Kern und in b) einen beispielhaften zweiten Kern zur Verwendung in einem Spritzgusswerkzeug gemäß der ersten Ausführungsform,
• 5 ein beispielhaftes skizzenhaft dargestelltes Sammelrohr gemäß einer ersten Ausführungsform,
• 6 einen beispielhaften skizzenhaft dargestellten Wärmetauscher, in dem ein Sammelrohr gemäß der ersten Ausführungsform verwendet wird.

Hereinafter, embodiments and modifications will be described with reference to accompanying figures, of which show

• 1 1 is a sketch-like perspective view of an exemplary injection mold in the open position according to a first embodiment,
• 2 a plan view of the syringe tool according to the first embodiment,
• 3 FIG. 3 is a cross-sectional view of the partially closed injection mold according to the first embodiment; FIG.
• 4 in a) an exemplary sketched first core and in b) an exemplary second core for use in an injection molding tool according to the first embodiment,
• 5 an exemplary sketchy illustrated collection tube according to a first embodiment,
• 6 an exemplary schematically illustrated heat exchanger in which a manifold according to the first embodiment is used.

That in the 3 completely and in the 1 and 2 partially shown injection molding tool (closing unit) according to an exemplary first embodiment is used to form a in 5 illustrated manifold 2 with a first length ( L1 ) in an X direction (longitudinal direction) and two openings 4 at its ends 6 in the longitudinal direction and a plurality of integrally formed terminal lugs 8th which are open in the longitudinal direction one after the other and in a Y-direction (transverse direction) which is perpendicular to the longitudinal direction. The manifold continues in this embodiment, as shown 5 it can be seen in the areas where no terminal lugs 8th are formed, preferably reinforcing ribs 9 on, which have a substantially rectangular outer contour in cross-section perpendicular to the longitudinal direction and are connected together in the longitudinal direction by a top and a bottom web. The reinforcing ribs are optional and their configuration can be varied.

As usual in injection molding tools, the device has a mold that is in two halves, namely a first molded part 10 (Forming agent) and a second molded part 12 (Forming agent), is divided. In the present embodiment, the first molded part extends 10 substantially rectangular in an XY plane, with the long side of the rectangle in the X direction (longitudinal direction) and the transverse side of the rectangle in the Y direction (transverse direction). The first molded part 10 is in a Z direction (height direction) on a base plate 14 (first clamping plate) mounted. The base plate 14 is adapted to be rigidly attached even to an injection unit, not shown.

The second molding 12 (Ejector) is adapted to be mounted in an injection molding machine to another, not shown second clamping plate. The second molding 12 is movable with the second platen by means of a traverse mechanism (not shown, mostly hydraulically) in the height direction Z between an opened state and a closed state. In the opened state is a predetermined distance between the first mold part 10 and the second molded part 12 guaranteed to remove an injection-molded manifold. When closed, the second molding comes 12 on the first molding 10 in a predetermined position, as in Fog. 3 is shown for lying. In this position, a first contact surface lying in an XY plane contacts 16 of the first molded part 10 a second contact surface lying in an XY plane 18 of the second molded part 12 ,

In every molding 10 . 12 are in the touch areas 16 . 18 first recesses 20 intended. The first recesses are preferably substantially symmetrical with respect to the contact surfaces 16 . 18 educated. When closed, the first recesses 20 a cavity 22 formed, which is the outer shape of the manifold to be produced 2 including connection lugs 8th and reinforcing ribs 9 Are defined. The through the first recesses 20 formed cavity thus has the first length ( L1 ) in the X-direction (longitudinal direction) for forming the longitudinal extent of the collection tube and a plurality of longitudinally successive and in the Y-direction (transverse direction) extending portions for forming the terminal lugs 8th , Thus, a removal of the manifold after injection molding is possible, the first recesses 20 each purely concave relative to the respective contact surface 16 . 18 educated.

Next are at the ends of the first recesses 20 in the longitudinal direction in the first and the second molded part 10 . 12 second recesses 24 formed by each one core 26 . 28 is inserted in the longitudinal direction, with which the cavity / interior of the manifold in the longitudinal direction X will be produced. Further, at the ends of the regions for forming the terminal lugs 8th the first recesses 20 third recesses 30 for a slider device 32 velvet in the cavity 22 (first recesses) insertable core pins 34 educated. The core pins 34 Similar to the cores, they serve to form the openings / channels in the terminal lugs 8th and the connection to the interior of the manifold 2 , The core pins are preferably arranged at a uniform distance from each other in the longitudinal direction, more preferably symmetrically with respect to the center of the collecting tube in the longitudinal direction. The connection lugs 8th are designed for later inclusion of connecting pipes.

A first core 26 is via a first Kernzuführvorrichung in the cavity 22 against the X- Direction insertable or retractable. A second core 28 is via a second Kernzuführvorrichtung in the cavity in the X direction, that is opposite to the first core 26 insertable. In the retracted position are both cores 26 . 28 pressed together. The Kernzuführvorrichtungen each have a displaceable in or against the X direction core plate 36 on. Each core plate 36 is slidable on sliding rods in the X direction 38 held to the base plate 14 are mounted in the longitudinal direction X extend. Every core 26 . 28 is preferably releasably attached to a respective core plate at one end 36 attached. To move each core plate 36 in the X direction is each core plate 36 via a hydraulic cylinder 39 with the base plate 14 connected. Preferably, the Kernzuführvorrichtungen can be locked in the retracted position. Preferably, the contact pressure of the cores against each other in the locked / retracted position via a spring (plate spring, not shown) is held, for example, between the core plate 36 and the core 26 . 28 is arranged. This ensures that the cores extending in the longitudinal direction due to the heat of the melt 26 . 28 bend or deform during rigid clamping.

To guide each core 26 . 28 when inserted into the cavity 22 is an exchangeable guide 40 (For example, socket) provided on the base plate 14 or the first molded part 10 (from inside to outside) following the second recess 24 is arranged.

4a shows a detailed view of the first core 26 . 4b a detailed view of the second core 28 , In this embodiment, the first core is 26 with a first end 26a and a second end 26b as a tubular body having a constant first inside diameter d1 educated. Starting from the first end 26a is the first core 26 divided in the longitudinal direction substantially into two sections. A first section 26c with a second length 12 in the longitudinal direction has a constant first outer diameter d2 on. A second section 26d with a third length 13 in the longitudinal direction, it tapers (with a first taper of k degrees) starting from the first section 26c conical to the second end 26b out. The first end 26a serves for fixing the first core 26 on the corresponding core plate 36 , The first end is preferred 26a therefore formed with a corresponding mounting flange.

The second end 26b is to connect to a second end 28b formed of the second core. This is the second end 26b in this embodiment, a frustoconical, tapered to the end hollow terminal extension 26e on, for insertion or insertion into a correspondingly complementary formed to the end conically widening connection receptacle 28e in the second end 28b of the second nucleus 28 suitable is. The connection extension 26e has a slight excess compared to the connection recording 28e so as to ensure a secure and tight fit. Alternatively or additionally, an O-ring may be provided.

Essentially analogous to the first core 26 is the second core in this embodiment 28 with a first end 28a and a second end 28b as a tubular body with preferably the same constant first inner diameter d1 educated. Starting from the first end 28a is the second core 28 is divided in the longitudinal direction substantially into two sections. A first section 28c with a fourth length 14 in the longitudinal direction has the constant first outer diameter d2 on and a second section 28d with a fifth length 15 in the longitudinal direction, it tapers (with the same first taper of k degrees) starting from the first section 28c conical to the second end 28b out. The first end 28a serves for fixing the first core 28 at the corresponding other core plate 36 , The first end is preferred 28a therefore formed with a corresponding mounting flange. The second end 28b is, as described above, for connection to a second end 26b of the first nucleus 26 with the connection recording 28e educated.

The lengths 13 and 15 the conical sections are preferably sized so that in the state in which the cores 26 . 28 into the cavity 22 retracted, located in the cavity 22 located part of each core 26 . 28 the second section 26d . 28d , which is conical, corresponds. This ensures that only the second sections 26d . 28d be surrounded by the melt and pulling out the cores 26 . 28 is facilitated due to the taper.

In the present embodiment, the lengths are 13 and 15 further formed differently, in such a way that the second ends 26b . 28b at a point with respect to the longitudinal direction of the cavity 22 meet that at least one of the ends 26b . 28b , prefers both ends 26b . 28b by retracting one of the core pins 34 , preferably one of the middle core pins 34 (with even number of core pins) or the middle core pin 34 (With an odd number of core pins) is in contact with this is or are.

The lengths 12 and 14 the first sections 26c . 28c are sized to the second sections 26d . 28d over the first sections 26c . 28c in the retracted state of the cores 26 . 28 through the second recess 24 and the guide 40 extend, at the core holding plates 36 are fastened.

The slider device 32 is designed to be the core pins 34 for forming the openings or interiors of the connection lugs 8th before feeding the melt into contact with the in the cavity 22 inserted cores 26 . 28 bring to. Because of the cores 26 . 28 formed and extending in the longitudinal direction tube interior (cavity) of the manifold 2 with the openings (cavities) of the connection lugs 8th should be communicatively connected, the core pins 36 that the openings of the terminal lugs 8th train, in close contact with the respective core 26 . 28 be brought (slide scrubbing). For this purpose, have the respective core facing the ends of the core pins 36 a concave surface corresponding to the respective position corresponding outer diameter of the respective core 26 . 28 corresponds and thus a sealing contact with the core 26 . 28 allowed. Next is the slider device 32 trained to the core pins 34 after curing of the melt from the cavity 22 to pull out in the third recesses. This will remove the manifold 2 from the moldings 10 . 12 allows.

Furthermore, in the contact surfaces 16 . 18 the molded parts 10 . 12 in each case a fourth recess 42 formed, with the at least one sprue 44 and two gating points 46 . 48 be formed. With the sprue 44 is the melt from the injection unit, not shown, to at least two gate points 46 . 48 that are in the cavity 22 open, guided.

It has proved to be advantageous, the gate points 46 . 48 based on the cavity 22 on the opposite side of the core pins 34 and parallel to the same (ie in the Y direction) in the cavity 22 open training. The gating points 46 . 48 are thus designed so that emerging from them melt meets the corresponding core and this in the direction of the core pins 34 suppressed. Thus, the cores become 26 . 28 when feeding the melt to the core pins 34 supported. In addition, the adjacent connection is reinforced from core to core pin.

A first starting point 46 is in a state in which the tool is closed and the cores 26 . 28 into the cavity 22 retracted, in the area of the first core 26 provided (see 2 , Position X1 ). A second gate point 48 is in a state in which the tool is closed and the cores 26 . 28 into the cavity 22 retracted, in the area of the second core 28 provided (see 2 , Position X2 ). In the present embodiment, the gate points are the same size and substantially the same volume flow of melt is supplied via the gate to each gate point.

As described above, it has been found to be advantageous not to arrange the gate points centrally with respect to the length of the corresponding core (area), but slightly outwards, that is offset to the outer ends of the cores. In other words: starting at one end in the longitudinal direction Z the cavity 22 with a total length L1 For example, the first core is preferably located at a position X1 1/8 × L1 <X1 <1/4 × L1, and the second core is preferably at a position X2 3 / 4 × L1 <X2 <7/8 × L1 (see 2 ). Even further out, the gate points should not be arranged, otherwise disadvantages may arise with regard to the connection of the melts in the middle (point of contact of the cores). The gate points preferably have the same distance to the point of contact of the two cores with one another, so that the individual, inwardly flowing melt streams essentially meet one another at the point of contact of the cores. Alternatively, the size or position of the gate points can be varied.

By feeding melt over the gate points 46 . 48 the melt is pressed into the cavity. The melt is inside the cavity 22 starting from the corresponding gate point 46 . 48 pressed in and against the longitudinal direction. By pressing the melt in one direction, the melt also exerts a force in the same direction on the respective core due to its adhesion to the respective core.

With only one gate point 46 . 48 per core 26 . 28 The forces per core in and against the longitudinal direction cancel at the beginning of the feeding of the melt, since the melt go out from the respective gate point 46 . 48 equally pressed in and against the longitudinal direction. With respect to a core centered arrangement of the respective gate point 46 . 48 this equilibrium of forces remains until the complete supply of the melt. At the here present displacement of the gate point 46 . 48 outward (away from the point where the retracted cores are connected), depending on the degree of outward displacement, after a time equilibrium phase, one becomes the corresponding core 26 . 28 inside, towards the other core 26 . 28 oppressive force. Because the cavity 22 is completely filled in one direction to the outside, before the cavity 22 is completely filled in one direction to the inside, the entire volume flow of the melt will ultimately be directed inwards and apply a corresponding force to the respective core.

Furthermore, a cooling device (not shown) for cooling the cores is preferred 26 . 28 provided by means of the cores 26 . 28 can be cooled. The cooling device is designed to be in a state in which the cores 26 . 28 into the cavity 22 are retracted and connected to a pipe, at an outer end of one of the cores 26 . 28 Compressed air for cooling the cores 26 . 28 from the inside. This allows the cores 26 . 28 be cooled during the feeding of the melt and during curing. Further, the cooling device is designed so that it during and after the extension or before and during the retraction of the cores 26 . 28 at the outer first ends 26a . 28a both cores 26 . 28 Compressed air for cooling the cores 26 . 28 from the inside. This allows the cores 26 . 28 after curing, ie during the extension and retraction of the cores 26 . 28 and in the extended state of the cores 26 . 28 be cooled.

Furthermore, a cooling device (not shown) for cooling the molded parts is preferred 10 . 12 provided by means of a cooling fluid, wherein in the moldings 10 . 12 cooling channels 49 are provided, through which a cooling fluid is passed.

In the following, the method is described, in which by means of the injection molding tool described above, the manifold 2 as it is in the 5 is shown is formed.

The in the 1 and 2 shown assembly (tool without second molding 12 ), as described above, fixedly mounted on an injection unit, preferably such that the longitudinal extent (X-direction) is vertical. The vertical arrangement allows the use of tools in conventional, designed for the injection volume injection molding machines without special adaptation. The second molding 12 is by means of a traversing mechanism in contact with the first molding 10 brought (and preferably locked), so that the cavity 22 between the moldings 10 . 12 is trained.

In a next step, the cores become 26 . 28 by means of the Kernzuführvorrichtung from both sides in opposite directions in the cavity 22 retracted and pressed together. The cores are in this case via the guide means or in the second recess 24 and through the core holding plates 36 kept or led. By providing the conical connection extension 26e at the first core 26 and the corresponding conical connection receptacle 28e in the second core 28 become the cores 26 . 28 aligned with the achievement of the end positions coaxially with each other and their interiors with each other to the environment, in particular to the cavity, tightly connected.

In a next step, by means of the slider device 32 the core pins 34 perpendicular to the longitudinal direction in the cavity 22 retracted and in contact with the cores 26 . 28 brought.

In this state, the injection of the melt through the fourth recess 42 ie the sprue 44 respectively. With the entry of the melt into the cavity 22 is in the range of the respective gate point 46 . 48 a force perpendicular to the longitudinal direction of the respective core 26 . 28 applied. A corresponding displacement or deformation of the respective core 26 . 28 is by means of opposite arranged core pins 34 prevented.

Due to the described positioning of the gate points 46 . 48 in the longitudinal direction is the force with which the cores 26 . 28 pressed in the middle, increased, at least not reduced.

For a high cycle time and uniform solidification of the melt, the cores 26 . 28 cooled by one side in the longitudinal direction X Compressed air is passed through both cores.

After solidification of the melt, the cores can 26 . 28 by means of hydraulic cylinders 39 be removed from the now solidified melt. The frictional forces between solidified melt and core acting in this process are reduced due to the conicity. Furthermore, the small outer diameters and the short lengths of the cores contribute to a low pull-out force. Preferably before extension of the cores 26 . 28 become the core pens 34 also moved outwards (perpendicular to the longitudinal direction), so that the cores 26 . 28 without additional friction on the core pins 34 can be moved out.

Already during the extraction, at the latest after that, for further cooling of the cores 26 . 28 both cores 26 . 28 supplied separately compressed air, for example by a dedicated 3/2 way valve is switched to a compressed air supply.

After moving out of the cores 26 . 28 and the core pins 34 becomes the second molding 12 removed and the injection-molded manifold 2 removed from the tool. In a post-processing, if necessary, through the sprue 44 removed webs removed.

The collection tube designed in this way 2 can, as it is in 6 is shown, then to form a heat exchanger 50 be used.

In addition, possible modifications will be the individual or in combination with the described embodiment and in the claims specified objects can be used described.

The core pins may also be oriented obliquely to the longitudinal direction and / or arranged irregularly. The reinforcing ribs partially shown in the figures are optional, in particular in the US Pat 1 to 3 shown cavity no corresponding recesses for forming such ribs shown.

The first length L1 of the manifold or the cavity 22 is preferably between 500 mm and 2000 mm, more preferably between 800 mm and 1300 mm, and more preferably between 950 mm and 1050 mm, such as 1014 mm (first preferred example) or 984 mm (second preferred example).

The second length 12 of the first section 26c of the first core 26 is preferably between 80 mm and 150 mm, more preferably between 90 mm and 130 mm, and more preferably between 110 mm and 130 mm, such as 126 mm (first and second preferred example).

The third length 13 of the second section 26d of the first core 26 without the connection extension 26e is preferably between 300 mm and 1000 mm, more preferably between 400 mm and 800 mm, and more preferably between 500 mm and 600 mm, such as 540.25 mm (first preferred example) or 540 mm (second preferred example).

The fourth length 14 of the first section 28c of the second core 28 is preferably between 80 mm and 150 mm, more preferably between 90 mm and 130 mm, and more preferably between 110 mm and 130 mm, such as 126 mm (first and second preferred example).

The fifth length 15 of the second section 28d of the second core 28 without the connection recording 28e is preferably between 300 mm and 900 mm, more preferably between 400 mm and 800 mm, and more preferably between 450 mm and 550 mm, such as 489.35 mm (first preferred example) or 489 mm (second preferred example).

The conicity k of the second sections 26d . 28d the cores 26 . 28 is preferably between 0.001 ° and 0.1 °, more preferably between 0.01 ° and 0.05 ° and even more preferably between 0.015 ° and 0.04 °, such as 0.02 °.

The first inner diameter d1 the cores are preferably 1 mm to 5 mm, more preferably 1.5 mm to 4 mm, and more preferably 2 mm to 3 mm, such as 2.5 mm (first and second preferred examples).

The second outer diameter d2 the cores 26 . 28 in their first sections 26c . 28c is preferably 8 mm to 30 mm, more preferably 10 mm to 15 mm, and more preferably 11 mm to 13 mm, such as 11.95 mm (first preferred example) or 12.2 mm (second preferred example).

The third outer diameter d3 the headers 2 or the inner diameter d3 the cavity 22 (Except for the reinforcing ribs, ie only the diameter which forms the tube itself, ie without reinforcing ribs) is preferably 8 mm to 40 mm, more preferably 12 mm to 20 mm and more preferably 14 mm to 18 mm, such as 16.2 mm (first and second preferred example).

The minimum wall thickness of the cores is preferably between 2 mm and 8 mm with a maximum overmoulded core length of 600 mm for non-conical cores.

The distance between the centers of the terminal lugs is preferably between 10 mm and 100 mm, more preferably between 20 mm and 80 mm, such as 50 mm or 70 mm.

It is explicitly pointed out that all features disclosed in the description and / or the claims are considered separate and independent of each other for the purpose of original disclosure as well as for the purpose of limiting the claimed invention independently of the feature combinations in the embodiments and / or the claims should. It is explicitly stated that all range indications or indications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of restricting the claimed invention, in particular also as the limit of a range indication.

As used herein, the terms "about," "about," "about," "substantially," or "generally," used in conjunction with a measurable value such as a parameter, quantity, shape, duration, or the like deviations or variations of ± 10% or less, preferably ± 5% or less, more preferably ± 1% or less and more preferably ± 0.1% of the respective value or of the respective value, if these deviations the implementation of the disclosed invention in practice are still technically useful. It is to be expressly understood that the value to which the term "about" refers is expressly and specifically disclosed as such. The specification of ranges by start and end values includes all those values and fractions of these values included by the particular range, as well as its start and end values.

LIST OF REFERENCE NUMBERS

2

manifold

4

Openings at ends in longitudinal direction

6

Ends in the longitudinal direction

8th

connection lugs

9

reinforcing ribs

10

first molded part (molding agent)

12

second molded part (molding agent)

14

baseplate

16

first contact surface

18

second contact surface

20

first recess

22

Cavity for manifold

24

second recess

26

first core

26a

first end

26b

second end

26c

first section

26d

second part

26e

Terminal extension

28

second core

28a

first end

28b

second end

28c

first section

28d

second part

28e

terminal receiving

30

third recess

32

Shift means

34

core pin

36

Core support plate

38

sliding bars

39

hydraulic cylinders

40

guide means

42

fourth recess

44

runner

46

first gate point

48

second gate point

49

cooling channels

50

heat exchangers

L1

Length of collecting pipe (first length)

12

first section first core

13

second section first core

14

first section second core

15

second section second core

d1

Inner diameter cores

d2

Outer diameter first section cores

d3

Outer diameter manifold (without reinforcement ribs)

Claims (12)

Tool for injection molding a collection tube (2) having a first length (L1) in the longitudinal direction (X) and two openings (4) at its ends (6) in the longitudinal direction (X) and a plurality of laterally longitudinally integrally formed terminal lugs (8) , comprising a first mold means (10) and a second mold means (12) movable relative to each other between a closed state and an opened state, wherein in the closed state between the mold means (10, 12) comprises a cavity (22) for injection molding A collection device (2) is formed, a slider device (32) with core pins (34) which are retractable at an angle to the longitudinal direction in the cavity (22), a first Kernzuführvorrichtung with a first core (26), as a rectilinear structure and from a first side in the longitudinal direction in the cavity (22) is formed retractable, a second Kernzuführvorrichtung with a second core (28), which is a rectilinear Ge and from a second side in the longitudinal direction in the cavity (22) is formed retractable, wherein the cores (26, 28) each have a front in the retraction direction end (26 b, 28 b), which for positive connection with the respective front lying End (26b, 28b) of the other core is formed, the Kernzuführvorrichtungen are adapted to keep the cores (26, 28) pressed in the retracted state during a supply of melt with a force to each other, the slide means (32) and the cavity (22) facing ends of the core pins (34) are formed so that the cavity (22) facing the ends of the core pins (34) retracted in the cavity (22) state on each one of the cores (26, 28) for forming the Abutment lugs, and at least two gating points (46, 48) are provided, via which the melt can be fed into the cavity (22), at least one first gating point (46) in the region of the first core (26) and a second gating point (46) in the region of second core (26) is provided, the gate points (46, 48) open on the core pins (34) opposite side of the cavity (22) in the cavity (22) and each formed at a position in the longitudinal direction and its size in that the melt is pressed into the cavity (22) from each gate point (46, 48) in and opposite to the longitudinal direction such that the force with which the cores (26, 28) move during the feeding of the melt by means of the Kernzuführvorrichtungen be pressed against each other during the feeding of the melt is not reduced by the melt. Tool after Claim 1 in which the first length (L1) of the cavity (22) for forming the manifold (2) satisfies the following condition: 500mm <L1 <2000mm, and / or an outer diameter (d3) of the manifold (2) formed in the cavity (22) ) is between 8 mm and 40 mm, and / or an outer diameter (d2) of the core is between 8 mm and 30 mm, and / or the wall thickness of the collecting tube (2) is between 1.3 mm and 4 mm. Tool after Claim 1 or 2 in that the lengths of the cores are formed so that at least one of the forward ends (26b, 28b) of the cores (26, 28) in the state of positive connection with the other front end (26b, 28b) after retraction of Core pins (34) in contact with one of the core pins (34). A tool according to any one of the preceding claims, wherein the melt which is supplied via the first gate point substantially at the point where the respective forward ends of the cores contact each other in the retracted state with the melt passing over the second gate point is supplied, comes into contact, and / or the position of the respective core (26, 28) associated with gate point (46, 48) and its size are selected so that at the immediately before the time of complete filling of the respective core ( 26, 28) corresponding part of the cavity (22) the sum of the volume flows of the melt in this part of the cavity in the direction of the other core (26, 28) to greater than the sum of the volume flows of the melt in this part of the cavity in the direction away from the other core (26, 28). A tool according to any one of the preceding claims, wherein a total of two gate points are provided, wherein a first gate for feeding melt is formed in the region of the first core and a second gate for feeding melt is formed in the region of the second core and each of the gate points in a distance in the longitudinal direction to the contact point of the cores in the retracted state is greater than half the length (13, 15) of the respective part of the core, which is in the retracted state in the cavity. A tool according to any one of the preceding claims, wherein the terminal lugs are opened in a first direction (Y) perpendicular to the longitudinal direction (X). Tool according to one of the preceding claims, wherein the cores (26, 28) are formed as a tube, and a cooling device for cooling the in the retracted state interconnected cores (26, 28) by passing air in or opposite to the longitudinal direction (X) by the two cores (26, 28) together and / or for cooling the non-interconnected in the extended state cores (26, 28) by jointly or separately passing air through each of the cores (26, 28) is provided. Tool according to one of the preceding claims, wherein the cores (26, 28) are at least partially cylindrical or have a constant cross-sectional shape in the longitudinal direction (X) and / or are at least partially conical, and / or the cores (26, 28 ) are tubular and the mutually facing ends (26b, 28b) of the cores (26, 28) have a Konuspassung, by means of which a coaxial, self-aligning and sealed connection between the cores (26, 28) is achieved. Tool according to one of the preceding claims, wherein the force with which the cores are held pressed against each other in the retracted state, is achieved in that at least one of the cores is held in the retracted position by a spring toward the other core to pressed , A method for injection molding a collection tube (2) having a first length (L1) in the longitudinal direction (X) and two openings (4) at its ends (6) in the longitudinal direction (X) and a plurality of integrally formed terminal lugs (8) in the longitudinal direction (X) successively and in a first direction (Y) which is perpendicular to the longitudinal direction (X) are opened, comprising the following steps: Retraction of two cores (26, 28) in a cavity formed between two shaping means (10, 12) (22) such that the facing ends (26b, 28b) of the cores are held pressed together with a force, Insertion of a plurality of longitudinally successive and at an angle to the cores extending core pins (34) for forming terminal lugs (8) such that the core pins (34) comes into contact with each of the cores (26, 28) , Injecting melt from an opposite side of the core pins (34) in the cavity (22) into the cavity (22) such that the force with which the cores (26, 28) are kept pressed against one another is not reduced by the injected melt removing the cores (26, 28) by withdrawing the cores (26, 98) from the cavity (22) in opposite directions in and against the longitudinal direction (X), opening the forming means (10, 12) and removing the injection molded article Collecting tube (2) after solidification of the melt. Method according to Claim 10 in which the cores (26, 28) are tubular and cooled by passing air therethrough during the introduction of the melt, during and / or before and / or after the entry and / or extension of the cores (26, 28) become. Injection molded collection tube (2) having a first length (L1) in the longitudinal direction (X) and two openings (4) at its ends (6) in the longitudinal direction (X) and a plurality of integrally formed attachment lugs (8) which are longitudinally (X) one behind the other and in a first direction (Y) which is perpendicular to the longitudinal direction (X), which is produced by the following method steps: Inserting two cores (26, 28) into a cavity (22) formed between two shaping means (10, 12) such that the mutually facing ends (26b, 28b) of the cores are held pressed together with a force, Inserting a plurality of core pins (34) running in the longitudinal direction one behind the other and at an angle to the cores to form connection projections (8) such that the core pins (34) come into contact with one of the cores (26, 28) in each case, Injecting melt from an opposite side of the core pins (34) in the cavity (22) into the cavity (22) such that the force with which the cores (26, 28) are held pressed against one another is not reduced by the injected melt . Removing the cores (26, 28) by pulling the cores (26, 98) out of the cavity (22) in mutually opposite directions in and against the longitudinal direction (X), Opening the molding means (10, 12) and remove the injection-molded collecting tube (2) after solidification of the melt.

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