EP1817151A1

EP1817151A1 - Moulded plastic article and a method for the production thereof

Info

Publication number: EP1817151A1
Application number: EP05817595A
Authority: EP
Inventors: Franz Hebauer; Jan WOKÖCK
Original assignee: Webasto SE
Current assignee: Webasto SE
Priority date: 2004-11-30
Filing date: 2005-11-22
Publication date: 2007-08-15
Also published as: CN101111357A; US20090008966A1; DE102004057810B4; DE102004057810A1; WO2006058515A1

Abstract

The invention relates to a moulded plastic article and to a method for the production thereof. Said moulded plastic article comprises an injection- or foam-moulded part (12) provided with at least one insert (16A) protruded with respect to said moulded part (12). According to said invention, an insert (24) penetrates through a deformable mould body (34) which forms a sealing element in the moulding cavity of a mould during the production of said injection- or foam-moulded part (12).

Description

Plastic molding and method for producing a

Plastics molding

The invention relates to a plastic molding according to the preamble of claim 1 and a method for producing a plastic molding according to the preamble of claim 10.

Plastic moldings, which are produced by a spray or foaming process, can be used in a variety of forms. In the field of automotive technology moldings are used for example as a sliding roof of a vehicle roof or as a circumferential plastic frame of a glass cover element of a sunroof.

Often it is necessary that a plastic molded part is provided with inserts which are embedded in a foamed or molded molding portion of the plastic molding and emerge from this. These form, for example, in a foamed sliding sky sliding elements for guiding the sliding headliner in a rail system or a sunroof tabs for connecting a cover member to the vehicle body.

In the production of a plastic molding which comprises a molding section formed in a mold cavity of a molding tool and provided with an insert part emerging from the molding section, it is necessary to seal the mold cavity to form the mold section, so that during injection or foaming of the mold section of the material used for the production of the mold section does not escape from the mold cavity. This seal may be problematic in the region of the exit of the insert from the mold section.

So far, the sealing of the mold cavity in the region of the insert by means of a plastic sealing profile, which is associated with a mold half of the mold, which forms the mold cavity with a second mold half. The sealing takes place here in the parting plane between the two mold halves.

The disadvantage, however, is that the sealing profile has to be changed regularly, which generates machine side times. The tool used for the production of the plastic molding can therefore be operated only with an increased cycle time. Furthermore, the costly sealing profile is subject to wear, which in turn leads to high tolerances. This is also a certain fluctuation in the sealing quality of the sealing profile.

Furthermore, the sealing can also be done by re-sealing by compressing the two tool halves, which are provided with precisely fitting surfaces. The seal of the mold cavity on accurately fitting surfaces but allows only very small tolerances. This in turn can lead to tooling problems.

The invention has for its object to provide a plastic molding and a method for producing a plastic molding, in which the above problems do not occur. This object is achieved by the plastic molding according to claim 1 and the method according to claim 10.

The invention therefore relates to a plastic molded part, in which an inserted during the production of the molding section sealing element, which is formed by the shaped body, is an integral part. By using such a sealing element, a reliable and cost-effective sealing in the region of an outlet of an insert part from a mold cavity for forming the mold section can be produced. Costly precautions on the mold need not be taken to seal the mold cavity in the exit region of the insert. The molded body may be shaped so that its visible surfaces are substantially aligned with the adjacent visible surfaces of the mold section, which in turn results in a harmonious appearance.

The formed as an injection molded part or as a foam plastic molding according to the invention may be formed in many forms and represents, for example, a sliding sky of a vehicle roof, in which case the mold portion forms a flat obscuring the sliding headliner and the insert preferably a sliding member for guiding the sliding headliner on a rail assembly. It is also conceivable, however, that the plastic molded part is a foamed plastic frame on a glass cover element of a vehicle sliding roof, are foamed at the inserts for connecting the cover element to the vehicle body. The plastic molding then represents only a part of the final product.

The molded body can not only serve to seal the mold cavity but can also perform functional tasks take. For example, the shaped body itself can form a sliding block for a movable component.

In order to ensure a reliable seal in the region of the exit of the insert from the mold cavity to form the mold section, it is expedient if the mold is arranged in the region of a parting plane of the mold and preferably has substantially opposite engagement surfaces for the mold. The mold acts upon closing on the attack surfaces, so that the Formkδrper undergoes a deformation due to the applied pressure, which in turn ensures the tightness of the mold cavity for the production of the mold section due to the resulting surface pressure.

The Formkδrper, which is penetrated by the insert is, in a preferred embodiment of the plastic molded part according to the invention an injection molded part. This can either be injection-molded directly on the insert or else be connected to the insert only after its manufacture. Also, the insert may be formed by a portion of a plastic profile or other plastic part.

If the molded body is connected to the insert only after its manufacture, it may be expedient that it consists of two parts which are connected to one another via a connecting device, for example a raster device.

In order to ensure a sufficient tightness in the region of the transition between the insert and the molding, it is advantageous in a subsequent attachment of the molding to the insert when the Shaped body has a recess for the passage of the insert, which is made with an undersize. This ensures that with closed mold high contact pressures between the insert and the molding result.

The forming a sealing element forming body may be formed of a material which enters into a frictional connection with this in the formation of the mold section and crosslinked with this. But it can also be provided that the mold section and the molded body are made of materials that do not accept liability. This is the case, for example, if the molded body is made of polypropylene and the mold section is formed of a polyurethane foam. In this case, it is advantageous if the shaped body has anchor devices for the material of the mold section. The anchor devices comprise, for example, holes which are introduced into the molded body and into which the material of the mold section penetrates, or else undercuts, so that the molded body is partially engaged behind by the injection-molded or foamed mold section.

In order to achieve a reliable seal of the mold cavity for forming the mold section in all regions of the molded body, it is advantageous if the mold has wedge-shaped flanks. In this way it is ensured that the mold used on the entire circumference of the molding body builds up a sufficiently large contact pressure. Surfaces that are aligned substantially parallel to the closing direction of the mold used, could lead to leakage problems during spraying or foaming of the mold section. Preferably, the shaped body is formed plastically deformable, so that it retains its shape after removal from the mold. Alternatively, it is also conceivable to use an elastically deformable material for the shaped body, which assumes its initial shape after its demoulding from the mold used for forming the mold section.

The invention further relates to a method for producing a plastic molding comprising a mold section and at least one insert in a mold. The mold comprises an apparent tool unit forming a mold cavity. According to the invention, in the method, the insert is provided with a deformable molded body, that the insert passes through the molding, the molding is arranged together with the insert in the region of an edge of the mold cavity, the tool unit is closed, so that the molding undergoes deformation and the Mold cavity is sealed in the region of the exit of the insert from the mold cavity through the mold body, and then a material for forming the mold section is introduced into the mold cavity, so that it connects to the insert and the molded body.

By using this method, the mold cavity can be reliably sealed in the region of the exit of the insert. Of course, the tool unit must be provided with a correspondingly shaped receiving area for the shaped body.

The seal in the region of the molded body can be further increased if the tool unit is provided in the region of the molded body with a pinch edge which engages in the molded body when the tool unit is closed. Alternatively or additionally, the shaped body may also be provided with a burr or the like, which engages in a groove of the tool unit.

Further advantages and advantageous embodiments of the article according to the invention are the description, the drawings and the claims removed.

An embodiment of a Kunststoffformkδrpers according to the invention and an inventively designed method for producing such a plastic molded part will be described in detail below with reference to the schematically simplified drawing. It shows

Figure 1 is a plan view of a sliding sky of a motor vehicle roof.

FIG. 2 shows a region of the sliding headliner comprising a sliding element and a sealing element; FIG.

Fig. 3 is a top perspective view of the

Sliding element and the sealing element in isolation;

4 is a plan view of the sliding element and the sealing element;

5 shows a side view of the sliding element and the sealing element;

Fig. 6 shows the arrangement of the sealing element in a mold; and

Fig. 7 is a schematic end view of an alternative embodiment of a sealing element.

In the figures 1 to 6 a sliding sky 10 of an otherwise not shown motor vehicle roof is shown, which serves to darken a closable by means of a glass cover roof opening. The sliding sky 10 is a plastic molding, which is a formed of polyurethane foam, a darkening element performing, flat mold section 12 with a ventilation cutout 14 and four pairs on both sides of the mold section 12 arranged sliding elements 16A, 16B ₇ 16C, 16D, which serve to guide the sliding headliner 10 in a sunroof associated, fixed roof rail assembly. The sliding elements 16A to 16D are each formed as an insert, which is foamed into the mold section 12 consisting of polyurethane.

As can be seen in particular from FIGS. 2 to 5, the sliding elements 16A to 16D each comprise a substantially plate-like foaming section 24 which is embedded in the mold section 12. The foaming portion 24 is connected via a connecting portion 26 with a leaf spring-like sliding spring 28 which is provided with two sliding shoes 30 and 32.

The connecting portion 26 of the sliding member passes through a molded body 34 which is an integral part of the sliding headliner 10 and is molded onto the insert-forming sliding member 16A, 16B, 16C and 16D, respectively, prior to foaming of the molding portion 12. The molded body 34 is made of polypropylene and forms a plastically deformable component.

In the production of the mold section 12 in a foaming mold, the molded body 34, as shown in Fig. 6, arranged in a corresponding recess 36 of an upper tool 38 and a lower tool 40 comprehensive tool unit of a mold, wherein the molded body 34 with closed tool unit, ie at to the lower tool 40 approached upper tool 38 is compressed in the direction indicated in Fig. 6 with Z, whereby a secure seal of here otherwise Not shown mold cavity for forming the flat obscuring element or mold section 12 takes place. In order to achieve a reliable sealing effect over the entire circumference of the molded body 34, the molded body 34 has wedge-shaped flanks 42 and 44, so that it is ensured that the molded body 34 is positively locking on all sides with a high sealing effect on the upper tool 38 and the lower tool 40, respectively is applied. The molded body 34 is arranged in the region of a parting line T shown in dashed lines in FIG. 6 of the tool unit formed by the upper tool 38 and the lower tool 40.

As can be seen in FIG. 3, in the region of the flanks 42 and 44, the shaped body 34 is provided on the side facing the mold section 12 with a hole 46 which represents an anchor device for the polyurethane material of the darkening element or mold section 12. The holes 46 thus ensure by the penetration of the not yet cured polyurethane material a frictional connection between the molded body 34 and the mold section 12th

The upper tool 38 and the lower tool 40 may each be provided in the region of the shaped body 34 with a squeezing edge not shown here, which engages in the molded body 34 in order to increase the sealing effect when the tool unit is closed. Alternatively, the molded body 34 may be circumferentially provided with a ridge, bead or the like, which engages in grooves of the upper tool 38 and the lower tool 40.

In the production of the sliding headliner 10 in the molding tool, a molded body 34 is first injection-molded in each case in the connecting regions 26 of the sliding elements 16A, 16B, 16C or 16D, so that a form-locking and Dense connection between the respective molded body 34 and the respective, an insert representing sliding member 16A, 16B, 16C and 16D is made and the respective insert engages the respective shaped body 34. Subsequently, the molded body 34 is arranged together with the relevant insert 16A, 16B, 16C or 16D in the region of an edge of a mold cavity for forming the sheet-like mold section 12. Then, the tool unit formed from the upper tool 38 and the lower tool 40 is closed, so that the shaped body 34 is squeezed perpendicular to the parting plane T and undergoes deformation and the mold cavity in the region of the exit of the relevant insert 16A, 16B, 16C and 16D from the Mold cavity is sealed by the respective molded body 34. Subsequently, a polyurethane foam for forming the mold section 12 is introduced into the mold cavity, so that it connects with the inserts 16 A to 16 D and the respective associated molded body 34.

In Fig. 7, an alternative embodiment of a shaped body 46 is shown. The shaped body 46 differs from the shaped body shown in FIGS. 2 to 6 in that it is formed from two parts 48, 50, which are connected to one another via snap-in connections 52 after their production by a spraying process, so that the relevant insert part has a recess 54 of the molding 46 passes through. In order to achieve a high density in the transition region between the shaped body 46 and the recess 54 by cross-insertion part, the recess 54 is provided in comparison to the dimensions of the insert in the connecting portion 26 between the Einschäumabschnitt 24 and the sliding spring 28 with an undersize. reference numeral

10 sliding sky

12 molding section

14 ventilation cutout

16A sliding element

16B sliding element

16C sliding element

16D sliding element

24 foaming section

26 connecting section

28 sliding spring

30 shoe

32 sliding shoe

34 moldings

36 recess

38 upper tool

40 lower tool

42 flank

44 flank

46 shaped bodies

48 part

50 part

52 snap connections

54 recess

Claims

Patent claims

A plastic molding comprising a molded or foamed molding section (12) having at least one insert (16A to 16D) extending from the molding section

(12), characterized in that the insert (16A to 16D) passes through a deformable shaped body (34, 46), which forms a sealing element for the mold cavity in the production of the mold portion (12) in a mold cavity of a mold.

2. Plastic molding according to claim 1, characterized in that the shaped body (34, 46) in the region of a parting plane (T) of the mold (38, 40) is arranged and preferably substantially opposing engagement surfaces for the mold (38, 40) ,

3. Plastic molding according to claim 1 or 2, characterized in that the shaped body (34) is injection-molded onto the insert.

4. Plastic molding according to claim 1 or 2, characterized in that the shaped body (46) consists of two parts (48, 50) which are connected via a Verbindüngs- device (52) with each other.

5. Plastic molding according to one of claims 1 to 4, characterized in that the shaped body (34, 46) Anchor devices for the material of the mold section (12) has.

6. Plastic molding according to one of claims 1 to 5, characterized in that the shaped body (34, 46) has wedge-shaped outgoing flanks.

7. Plastic molding according to one of claims 1 to 6, characterized in that the shaped body (34, 46) is plastically deformable.

8. plastic molding according to one of claims 1 to 7, characterized in that it is a sliding sky (10) for a motor vehicle roof.

9. plastic molding according to claim 8, characterized in that the insert part (16A to 16D) comprises a sliding element for the sliding headliner (10).

10. A method for producing a molding section

(12) and at least one insert (16A to 16D) comprising plastic molding (10) in a mold having an apparent tool unit (38, 40) in which a mold cavity is formed, characterized in that the insert (16A to 16D) is provided with a deformable shaped body (34, 46) such that the insert part (16A to 16D) passes through the shaped body (34, 46), that of the shaped body

(34, 46) is arranged together with the insert (16A to 16D) in the region of an edge of the mold cavity that the tool unit (38, 40) is closed, so that the shaped body (34, 46) undergoes a deformation and the mold cavity in Portion of the exit of the insert (16A to 16D) from the mold cavity by the Formkδrper (34, 46) is sealed, and a material for forming the mold section (12) is introduced into the mold cavity so that the material bonds to the insert (16A to 16D) and the mold (34, 46).

11. The method according to claim 10, characterized in that the shaped body (34) is injection-molded onto the insert (16A to 16D).

12. The method according to claim 10 or 11, characterized in that the tool unit (38, 40) in the region of the Formkδrpers (34, 46) is provided with a pinch edge, which when the tool unit is closed

(38, 40) engages in the shaped body (34, 46).