WO2010031481A1

WO2010031481A1 - Plastic pipe

Info

Publication number: WO2010031481A1
Application number: PCT/EP2009/006073
Authority: WO
Inventors: Gerhard Kuhnert; Nils Rapp
Original assignee: Ebm-Papst St. Georgen Gmbh & Co. Kg
Priority date: 2008-09-22
Filing date: 2009-08-21
Publication date: 2010-03-25
Also published as: DE202009011641U1; DE212009000120U1; DE112009002097A5

Abstract

The invention relates to a plastic pipe (26) for connecting to an opening (22) defined by an edge (24), made of a thermoplastic plastic that is hard at an operating temperature having a circumferential sealing element (30) made in a 2K process and made of an elastomeric soft component at an area designed for connecting to such an opening (22), the latter connected by fusing to the plastic pipe (26) at the interface thereto. Said sealing element (30) has a circumferential ring groove (36) on the exterior thereof, designed for receiving such an edge (24) during assembly under at least temporary deformation of the soft component (30).

Description

Plastic pipe

The invention relates to a plastic pipe, as it finds particularly for the transport of cooling air use. Pipe pieces of such plastic pipes are often used for the production of pipe systems, which can be quite complex and e.g. serve to transport air from a central fan to various devices that need to be cooled. Because of the strange shape of such pipe systems (air duct systems) one occasionally speaks of a "deer antler".

Such air duct systems must be designed very carefully, so that a uniform and low back pressure is guaranteed. This means that such pipe sections must not have abrupt cross-sectional changes, bottlenecks, dead spaces and paragraphs. Such aerodynamic optimization lowers the operating noise, increases the amount of cooling air, and facilitates subsequent retrofitting of additional components with cooling air demand.

For connecting such pipe pieces with corresponding counterparts, e.g. with a so-called air box, one uses so-called fixing straps on which screws are provided, and during assembly, these screws are screwed to the air box or the like, which requires depending on the mounting point correspondingly long assembly times and increases the cost.

It is therefore an object of the invention to provide a new plastic tube.

According to the invention this object is achieved by the subject of the protection claim. 1

Further details and advantageous developments of the invention will become apparent from the hereinafter described and illustrated in the drawings, in no way as a limitation of the invention to be understood embodiments, and from the dependent claims. It shows: 1 is a plastic tube, which is provided on its right side with a peripheral element made of a soft component, before snapping into the opening of a wall, which is shown in Fig. 1, right

2 is a section, taken along the line II - II of FIG. 1,

3 shows an intermediate step shortly before latching,

4 the plastic tube of FIG. 1 to 3 in the locked state,

5, the arrangement of FIG. 4, in which with the free end of the plastic raw res a radial fan is connected, which is driven by a brushless DC motor,

6 shows the arrangement according to FIG. 5 in longitudinal section, FIG.

7 is an enlarged view of the detail VII of FIG. 6,

8 shows a rotatable mold for the production of the plastic pipe shown in FIG. 1 on the left side in the so-called direct 2K process, FIG.

9 shows a variant of FIG. 8 for producing a peripheral sealing element made of a soft component in the so-called indirect 2K method, FIG.

10 is a view similar to FIG. 9, for a better explanation,

1 1 is a perspective view of a mold with the shape of FIGS. 9 and 10 produced,

Fig. 12 is an enlarged view of the detail XII of Fig. 1 1, and

Fig. 13 is a longitudinal section through the front in Fig. 1 1 end of the pipe section shown there. In the following description, like or equivalent parts will be denoted by the same reference numerals and described only once. Terms such as left, right, up, down refer to the respective figure.

1 shows symbolically a part of an air box 20 on the right. This has an opening 22 with a rim 24. The opening 22 serves for fastening the right end 28 of a

Plastic tube 26 made of a thermoplastic material, e.g. out

PE - polyethylene

PE-HD - high density polyethylene

PA - polyamide

PP - polypropylene, or other suitable thermoplastic material. This is dimensionally stable at the temperatures occurring during operation.

The right end of the tube 26 is provided with a support 30 made of a suitable elastomer. Suitable for this are, inter alia .:

TPE - thermoplastic elastomer

Santopren® - Elastomer

silicone

These material specifications apply to all embodiments.

Fig. 2 shows an enlarged section - along the line Il - Il of Fig. 1 -. Through the support 30. The latter is located in a groove 34 of the plastic roh res 26 and has even at its outer periphery a groove 36, which in the thickness the edge 24 is adapted, cf. Fig. 7. On its right side, the support 30 has a frusto-conical portion 38 which facilitates insertion into the opening 22, and on its left side has a portion 40 whose right edge 41 defines the groove 36.

3 shows an intermediate step in the attachment of the pipe section 26 in the opening 22.

Fig. 4 shows the pipe section 26 after its attachment in the opening 22. The edge 24 is engaged in the groove 36 (Fig. 2). So you get a connection that's very simple can be made by the tubular portion 26 is pressed with its elastomeric support 30 in the opening 22 so that the support 30 engages in the opening 22. Such a compound is largely dense, so has little air loss, and it can be easily and inexpensively manufactured, because an additional screw is not needed in most cases. The elastomer pad 30 also causes noise damping and decoupling.

Fig. 5 shows how a radial fan 46 is fastened with its outlet 48 to a connecting member 50 at the left end of the plastic pipe 26. In this case, the outlet pipe 48 of the fan 46 is inserted into the connecting member 54 and locked there. To drive the radial fan 46 is preferably a brushless DC motor 52, as this results in a particularly quiet running of the fan 46 and a high efficiency. The latter is particularly important in cooling applications, since in this case the air sucked in by the fan 46 is hardly heated by it.

Fig. 6 also shows the fan 46 and its locking connection with the connecting member 50 of the tube 26. This connection is very advantageous. It is the subject of DE 20 2007 018 175.2 of 16.12.2007.

FIG. 7 shows an enlarged view of the detail VII of FIG. 6. The pipe section 26 has the circumferential groove 34 at its left end, and into this the support 30 is injected by 2K injection molding, as explained below with reference to FIG is, so that the material of the support 30 merges with the groove 34 and thus forms a very strong and durable connection. In the support 30 is the circumferential annular groove 36, in which the edge 24 is engaged. For this purpose, the support 30 has the sloping flank in the form of the frusto-conical portion 38, which facilitates the insertion of the tube 26 into the opening 22 (Figure 1), which opening is defined by the rim 24. In this way you get a largely airtight connection that can be easily mounted. In most cases, you do not need any tools to assemble, but you need a force that can be applied by hand.

Fig. 8 shows a mold plate 56. This has a rotatable mold insert 58, which is provided on the left with a cavity 60 for the hard component, so in the example for the production of the plastic pipe 26. Right, the mold insert 58 has a cavity 62 for the production the soft component 30.

First, therefore, in the cavity 60, the hard component of the tube 26 is injection-molded, and then the mold insert 58 is rotated, and the soft component 30 as shown in FIG. 1 and FIG. 2 is formed on the right in the 2K process.

The mold plate 56 has two inflow channels:

On the left, a channel 64 for the material of the hard component, ie of the tube 26. On the right, the mold insert 58 has a cavity 62 for the soft component 30.

First, in the cavity 60, the tube 26 is made of the hard component. Then, the mold insert 58 is rotated, and on the right, the soft component 30 is produced, as shown in Figs. 1 and 2.

It is therefore a so-called direct 2K injection molding process, by which one obtains an excellent connection between the tube 26 and the elastomeric pad 30.

For reasons of better manufacturing accuracy, it is generally preferred to use tubes which are produced as injection-molded parts. For example, 1 to 8 show a tube 26 which can be produced by injection molding. However, this manufacturing method is possible only with relatively simple parts.

9 shows, as a counter-example, a plastic tube 26 'which, because of its shape, can not be produced by injection molding. Therefore, it is made as a blow molding tube made of a thermoplastic material.

In such Formblasrohren can be used with advantage for the production of a mold, as shown and described in FIGS. 9 to 13.

For long pipes you would need according to the method of FIG. 8 very large and therefore expensive forms. Especially in these cases, one can advantageously use a mold as shown and described in FIGS. 9 to 13. In this case, use is made of a mold 70 with a cavity 72 into which the blow-molding tube 26 'is inserted after its manufacture and which is therefore designed such that it fits into the cavity 72. The tube 26 'is inserted in Fig. 9 in the direction of arrow 78 in the cavity 72.

At the end 80 of the tube 26 'is here in the so-called indirect 2K process, a soft component molded. Therefore, the cavity 72 has a corresponding annular groove 82, of which in Fig. 9, only the lower half is visible.

The right end 80 of the tube 26 '(hard plastic) fits snugly into the cavity 72 but, as shown in Fig. 9, has no radial protrusions protruding into the annular groove 82, but forms a radially inner boundary for the annular groove 82nd

A feed line 84 for the elastomeric material used for the soft component 30 "leads to the annular groove 82, so that the right end 80 of the blow molded part 26 'can be overmolded by the soft line 30' in this 2K process, see FIG. 10. In this case, the hot soft component 30 "melts the material at the end 80 of the blow molding tube 26 ', so that a close, intimate connection between the blow molding tube 26' and the soft component 30 'is formed.

Figs. 11 to 13 show the end result of the process just described. At the pipe end 80 is now the ring of the soft component 30 ', which, as in Fig. 2, is provided with an annular channel 36.

Fig. 12 shows an enlarged view of the detail XII of Fig. 1 1. The annular channel 36 is bounded on the right by a shoulder 86. The shoulder 86 is formed by a ring 88, which, as shown, may have an approximately rectangular cross-section.

On its left in Fig. 11 and 12 side of the channel 36 has a shoulder 90, and from this he goes into a frusto-conical portion 92 on. This goes in turn into the outside of the pipe section 80, as shown in Fig. 13.

By the method used is obtained here also a material connection between the tube 26 'made of hard plastic and the material of the soft component 30'. The Manufacturing is easy and very safe. This also makes it possible to attach the soft component, as shown, to the end of the tube 26 or 26 ', cf. eg Fig. 4.

Naturally, many modifications and modifications are possible within the scope of the invention, e.g. by modification of the shape and material of the soft component 30 'according to the respective requirements, especially with regard to the noise insulation.

Claims

claims

, Plastic pipe (26, 26 ') for connection to an opening (22) defined by an edge (24), which pipe is formed from a thermoplastic material which is hard at operating temperature and at a region adapted for connection to such an opening (22) is, with a manufactured in 2K process, circumferential sealing element (30;

30 ') is provided from an elastomeric soft component, which

Soft component at the interface with the plastic pipe with this through

Anchmelzen is connected, which sealing element (30) on its outer side a circumferential annular groove (36) which is adapted to receive during assembly under at least temporary deformation of the soft component (30) such a rim (24).

2. Plastic pipe according to claim 1, wherein the circumferential sealing element (30) is made in the direct 2K process.

3. Plastic pipe according to claim 1, wherein the peripheral sealing element (30 ¹ ) is produced in the indirect 2K process.

4. Plastic pipe according to claim 2, which is designed as an injection molded part (26).

5. Plastic pipe according to claim 4, wherein the circumferential sealing element (30) in a on the outside of the plastic tube (26) provided groove (34) is fixed by the 2K plastic injection process.

6. Plastic pipe according to claim 3, which is formed as a blow molding (26 ').

7. Plastic pipe according to claim 6, wherein the blow molding (26 ') is encapsulated on its outside with the soft component of the peripheral sealing element (30') in the 2K process, so that the sealing element (30 ¹ ) is connected by fusing with this outer side ,

8. Plastic pipe according to claim 7, which forms an insert of the injection mold (70) during encapsulation, so that the sealing element (30 ¹ ) by injecting the soft component into a between the injection mold (70) and the outside of the blow molding tube (26 ') formed mold cavity (82) can be generated.

9. Plastic pipe according to one of the preceding claims, wherein the sealing element (30, 30 ') in the region of a pipe end (80) is provided.

10. Plastic pipe according to one of the preceding claims, wherein a pipe end with a fan (46) is connected.

1 1. Plastic pipe according to claim 10, in which the blower (46) is connected to the plastic pipe (26, 26 ') by a plug-in connection designed as a latching connection.

12. Plastic pipe according to claim 10 or 1 1, wherein the blower (46) is designed as a radial fan.