FR2964903A1 - Thermoforming mold for panel of motor vehicle, has application unit moved between retracted position in which application unit is arranged in part and erected position in which receiving surface is applied against application surface - Google Patents

Abstract

The mold (1) has a skin covering a support and a decoration element arranged on the skin. Two parts (2, 4) are provided with respective application surfaces (6, 8) arranged opposite to each other. The parts are moved with respect to each other, so as to allow application of the skin on the support. An application unit (20) is moved between a retracted position in which the application unit is arranged in one of the parts, and an erected position in which a receiving surface (22) is applied against one of the application surfaces of the other part. An independent claim is also included for a method for realizing a part of a motor vehicle.

Description

The present invention relates to a thermoforming mold of a motor vehicle part comprising a support, a skin covering said support and at least one decorative element disposed on said skin. , said mold comprising a first portion and a second portion each comprising an application surface, arranged opposite one another, of a shape substantially corresponding to the shape of the motor vehicle part, said parts being movable the one with respect to the other so as to allow the application of the skin on the support by pressure of an application surface on the other application surface, the skin and the support being interposed between said parts of the mold . The invention also relates to a method of producing a motor vehicle part by means of such a mold and a dashboard panel of a motor vehicle obtained by such a method.

It is known to produce motor vehicle parts, for example dashboard panels, by thermoforming by means of a mold comprising two moving parts applying the skin against the support and making them adhere to each other by thermoforming. In some cases, it is desired to add a decorative element on the surface of the piece, that is to say on the skin, to improve its appearance. These decorative elements are for example made in the form of sheets cut into a particular shape and applied locally on the skin during the application of the skin against the support. To do this, the decorative element is previously held against the second mold part opposite the area where it must be applied against the skin. When the mold is closed, the decorative element is pressed against the skin and adheres to it. The application and positioning of the decorative element on the application surface of the second mold part are therefore important steps in the process of producing the part in order to obtain a part having a satisfactory appearance. In order to obtain a correct positioning of the decorative element, the operation of applying the decorative element to the second part of the mold is generally carried out by a robot carrying the decorative element, moving between the first part of the mold and the second mold part and comprising means for applying the decorative element against the second part of the mold. However, in case of mishandling or malfunction of the robot, it may be that it hits one or the other part of the mold and damages it. The slightest defect of the mold can modify one or the other application surface of the mold parts, which causes a manufacturing defect parts. Thus, in case of damage to the mold, it is necessary to stop the production line and repair or even replace the mold, which leads to significant costs and a loss of production rate of motor vehicle parts.

One of the aims of the invention is to overcome these drawbacks by proposing a thermoforming mold for accurately positioning a decorative element while dispensing with a robot so as to protect the thermoforming mold. For this purpose, the invention relates to a thermoforming mold of the aforementioned type, in which the first part of the mold comprises means for applying the decorative element against the second mold part, said application means comprising at least a receiving surface of a decorative element and being movable between a retracted position, wherein said means is disposed in the first mold part, and an erected position, wherein said receiving surface is applied against the application surface of said second mold part.

Thus, the application means of the decorative element are integrated into the mold, which ensures a precise positioning of the decorative element while passing a robot. The mold does not run the risk of being damaged. In addition, the production rates of the motor vehicle parts can be increased, the method of making the parts does not include a step of moving the robot between the parts of the mold. According to other characteristics of the mold: the receiving surface of the decorative element has a shape substantially complementary to a part of the application surface of the second mold part, said part of the receiving surface of application and now said decorative element after the application of the decorative element against said part by the application means in erected position; - The application means comprise at least one cylinder carrying the receiving surface, said actuator actuating the displacement of the receiving surface between the retracted position and the erected position; the receiving surface forms part of the application surface of the first mold part when the application means are in the retracted position, the said receiving surface projecting from the said application surface when the application means are in the retracted position; erected position; the application means comprise at least one compensation element having a holding surface, said holding surface projecting from the receiving surface so as to be flush with the application surface of the first mold part when the application means are in the retracted position; - The application surface of the first mold part is retractable, said surface being retracted when the application means are in the erected position and said surface covering the application means when the application means are in the retracted position; - The mold comprises at least two receiving surfaces, each for receiving a decorative element.

The invention also relates to a method for producing a motor vehicle part, comprising a support, a skin covering said support and at least one decorative element disposed on said skin, by means of a mold as described above, comprising the following steps: - arranging a decorative element on the receiving surface of the application means; actuating the application means so as to move them into an erected position and to apply the decorative element against the application surface of the second mold part; - Pass the actuating means in the retracted position; arranging the support and the skin of the motor vehicle part between the first and second mold parts; - bringing the first and second mold parts together so as to apply the skin against the support and to adhere to one another by thermoforming, the decorative element being applied and adhered against the skin ; separating the two mold parts and removing the motor vehicle part from the mold. According to another characteristic of the method, an adhesive is applied against both sides of the decorative element so as to adhere the decorative element against the second mold part when the application means pass from the erected position to the retracted position and then adhere the decorative element to the skin when the second mold part is applied against the skin to apply the skin on the support. The invention also relates to a motor vehicle dashboard panel comprising a support, a skin covering said support and at least one decorative element disposed on said skin, said panel being obtained by a production method as described above. .

Other aspects and advantages of the invention will appear on reading the description which follows, given by way of example and with reference to the appended drawings, in which: FIG. 1 is a diagrammatic sectional representation of a thermoforming mold according to a first embodiment of the invention, FIG. 2 is a diagrammatic representation in perspective of a part of the application means of a decorative element used in the thermoforming mold of FIG. 1, - FIG. 3 is a diagrammatic representation in section along the axis III-III of FIG. 2, a support being disposed on the application surface of the first mold part - FIG. 4 is a schematic representation in section similar to FIG. 3, the application means being in erect position, a decorative element being disposed on the receiving surface of the application means, - FIG. 5 is a diagrammatic sectional representation of a thermoforming mold according to a second embodiment of the invention; FIGS. 6 to 11 are diagrammatic representations of the different steps of producing a motor vehicle part by means of the mold of FIG. 1. With reference to FIG. 1, there is described a thermoforming mold 1 comprising a first part 2 and a second part 4 movable relative to each other between a spaced position (FIG 1) and a close position forming the piece by thermoforming, as represented by the arrow F of FIG. 1. Thermoforming is also understood to mean thermogolding. The first 2 and the second 4 mold parts each comprise an application surface, respectively 6 and 8, arranged facing one another and shapes corresponding to the shape of the part to be produced. The application surface 6 of the first mold part 2 is intended to receive a support 10 (FIGS 3 and 9 to 11) of a shape substantially complementary to the application surface 6. A skin 12 (FIGS. ) for covering the support 10 is interposed between the support 10 received on the application surface 6 of the first part 2 and the application surface 8 of the second mold part 4. Thus, when the two mold parts 2 and 4 go to the close position, the skin 12 is applied against the support 10, matches the shape of the support 10 and adheres thereto by thermoforming. A piece 14 is thus obtained (Fig. 11). The support 10 may be an insert belonging to the part 14 or a forming aid element which does not belong to the part 14 and which is removed from it when the part 14 is made.

A decorative element 16, for example made in the form of a cut sheet, is intended to be placed on the skin 12 in a skin application zone. This skin application zone 12 corresponds to a portion 18 of the application surface 8 of the second mold part 4 on which the decorative element 16 must be applied and held to end up in the application zone. of the skin 12 when the two mold parts pass into the close position. Indeed, in the close position, the application surface 8 of the second mold part 4 is applied against the skin 12 opposite the support 10. It is therefore necessary to insert the decorative element 16 between the skin 12 and the application surface of the second mold part 4 opposite the skin application zone 12. To do this, the first mold part 2 comprises means 20 for applying the decorative element 16 against the second part 4 of mold. These application means 20 comprise a receiving surface 22 of a decorative element 16, for example formed by a shoe 24 comprising a footprint 26 extending in depth from the pad and having a shape corresponding to that of the element of FIG. decor 16, as shown in FIG. 2. The receiving surface 22 is disposed opposite the portion 18 of the application surface 8 of the second mold portion 4 facing the skin application zone 12 and has a shape substantially complementary to the this part 18. The application means 20 furthermore comprise a jack 28 carrying the receiving surface 22 and making it possible to move it between a retracted position (FIG 1, 3, 5), in which the application means 20 are arranged in the first mold part 2, and an erected position. 4), in which the receiving surface 22 is applied against the application surface 8 of said second mold part 4, as represented by the arrows F 'of FIG. 7. The receiving surface 22 having a shape substantially complementary to that of the portion 18 of the application surface 8 of the second mold part 4 lying opposite the application area of the skin, it is ensured and the decorative element 16 will perfectly match the shape of the part 14 to form. According to the embodiments shown in the figures, the application means 20 comprise two receiving surfaces 22 and two cylinders 28 for applying two distinct decor elements 16 to the second mold part 4. It is of course conceivable to provide more receiving surfaces and cylinders depending on the part 14 to be produced and the number of decorative elements that it is desired to integrate. According to a first embodiment shown in FIGS. 1 to 4 and 6 to 11, the application means 20 are such that the receiving surface 22 forms part of the application surface 6 of the first mold part 2 when the application means 20 are in the retracted position . That is, the support 10 of the workpiece 14 is applied to the receiving surface 22 when the application means 20 are in the retracted position, as shown in FIG. 3. However, there is a difference in shape between the receiving surface 22 and the application surface 6 of the first mold part 2 facing the part 18 of the application surface 8 of the second mold part 4 . Indeed, the application surface 6 of the first mold part 2 and the application surface 8 of the second mold part 4 have substantially the same shape, but with different dimensions to compensate for the thickness of the support 10 and of the skin 12 when they are arranged between the first and second mold parts. Thus, as shown in Figs. 1 and 3, there is a gap d between the receiving surface 22 and the application surface 6, when the application means 20 are in the retracted position. However, it is important that the support 10 is uniformly supported by the application surface 6, including in the area of the receiving surface 22, since the skin 12 is applied against the support 10, in particular by vacuum suction against the surface. 6. Thus, if the support 10 is not uniformly supported on the application surface 6, the part 14 will have surface defects in the area of the receiving surface 22. To compensate for the difference d the receiving surface 22 and the application surface 6, the application means comprise at least one compensating element 30 having a holding surface 32, said holding surface 32 projecting from the receiving surface 22 so as to be flush with the application surface 6 of the first part 2 of the mold when the application means 20 are in the retracted position, as shown in FIGS. 2 and 3. Thus, the holding surface 32 has the shape that should have the application surface 6 in the area of the receiving surface 22 if this receiving surface 22 was not present. The compensation element 30 is for example formed by a fixed stud disposed in a bore provided in the shoe 24. Thus, in the retracted position, the support 10 bears on the application surface 6 of the first mold part 2 and on the holding surface 32 of the compensating member 30 in the area of the receiving surface 22, as shown in FIG. 3. In order to determine the shape of the receiving surface 22 and the distance the compensation element 30 exceeds the receiving surface 22 when the application means 20 are in the retracted position, the limit of the part 18 of the the application surface 8 of the second mold part 4, the shape determined by this limit is translated until it cuts the application surface 6 of the first mold part 2, which gives the direction of translation of the application means 20 between the retracted position and the erected position, as well as the distance d between the receiving surface 22 and the application surface 6 and makes it possible to form the compensation element 30 accordingly. Depending on the size of the receiving surface 22, it is to be understood that a plurality of compensating elements can be provided, as shown in FIG. 2 to allow adequate support of the support 10 without the part 14 to be formed is deformed during the suction of the support 10 and the skin 12. In erected position, the receiving surface 22 is projecting from the surface 6 of the first mold part 2 and the compensation element 30 remains fixed, as shown in FIG. 4, so that the decorative element 16 can be disposed in the cavity 26 and adopt the shape of the portion 18 of the application surface 8 of the second mold part 4. According to a second embodiment shown in FIG. 5, the application surface 6 of the first part 2 of the mold is retractable and the application means 20 are arranged under this application surface 6 retractable. According to this embodiment, the first mold part 2 is made in two elements 34 and 36, a first element 34 carrying the application surface 6 and a second element 36 carrying the application means 20. The first element 34 is movable relative to the second member 36 so as to cover the second member 36 and the application means 20 when the application means 20 are in the retracted position and to be retracted from the second member 36 when the application means 20 are moved from the retracted position at the erected position. Thus, when the first element 34 is retracted, the application means 20 are opposite the application surface 8 of the second mold part 4, whereas when the first element 34 covers the application means 20, it is the application surface 6 of the first mold part 2 which faces the application surface 8 of the second mold part 4. Thus, it is not necessary to provide a compensating element, the application surface 6 being formed continuously to the appropriate shape. The method for producing the part 14 by means of the thermoforming mold 1 described above with reference to FIGS. 6 to 11.

In the embodiments shown in the figures, the first mold part 2 is movable under the second mold part 4 so that it can be opposite an operator 38, in order to facilitate the operator's manipulations 38. However, it is understood that this movement is optional and that the operator 38 could intervene on the first mold part 2 while it is under the second part 4 of the mold.

In a first step shown in FIG. 6, the operator 38 places the decorative element (s) 16 in the indentations 26 of the receiving surface 22. With a mold according to the embodiment of FIG. 1, the receiving surface 22 is slightly out of the retracted position to protrude above the compensation member 30 so that the impression 26 is fully accessible. With a mold according to the embodiment of FIG. 5, the first element 34 of the first mold part is retracted or the second element 36 of the first mold part is moved alone to face the operator 38. An adhesive has previously been applied against both sides of the mold. decorative element 16. The adhesive layers are for example protected by a peelable film. When the decorative element 16 is placed in its cavity 26, the operator removes the peelable film from the face of the decorative element intended to be applied against the application surface 6 of the second mold part 4. In a second step, shown in FIG. 7, the first mold part 2 is placed facing the second mold part 4 and the application means 20 are placed in their erected position so as to apply the decorative element 16 against the part 18 of the mold surface. application 8 of the second mold part 4. Then, the application means 20 are returned to their retracted position (FIG 8) and the decorative element (s) adhere to the application surface (8) of the second mold part (4) thanks to the layer of adhesive applied on the face applied against the application surface 8. With a mold 1 according to the second embodiment, the first element 34 is placed above the second element 36 so that the application surface 6 of the first part 2 of mold covers the application means 20.

In the step shown in FIG. 9, the operator 38 places the support 10 on the application surface 6 of the first mold part 2, and then interposes the skin 12 between the two mold parts (FIG 10). The operator 38 also removes the peelable film protecting the layer of adhesive disposed on the face of the decorative element 16 arranged facing the skin 12.

Finally, the two mold parts are placed in their close position so as to adhere the skin 12 to the support 10 by thermoforming. The skin 12 is for example sucked against the support 10 and the heat makes it possible to adhere this skin 12 to the support 10. The suction and the layer of adhesive provided under the decorative element 16 also make it possible to adhere the decorative element 16 to the skin 12 in the area of application of the skin 12.

The mold 1 described above eliminates the robot usually used to place the decorative element 16 against the application surface 8 of the second mold part 4. Thus, there is no risk of damaging the mold 1, in case of mishandling of the robot or malfunction of it. The mold 1 also makes it possible to very precisely position the decorative element 16 in a simple manner and offers high production rates. The mold and the method described above are particularly suitable for forming motor vehicle dashboard panels, comprising a support 10 covered by a skin 12 decorated by at least one decorative element 16. However, it is understood that they can be applied to form any other piece by thermoforming.

Claims (1)

1. Thermoforming mold (1) of a part (14) of a motor vehicle comprising a support (10), a skin (12) covering said support (10) and at least one decorative element (16) disposed on said skin (12), said mold comprising a first portion (2) and a second portion (4) each comprising an application surface (6, 8), arranged facing one another, of a shape substantially corresponding to the shape of the motor vehicle part (14), said parts (2, 4) being movable relative to each other so as to allow the application of the skin (12) to the support (10) by pressing an application surface (6, 8) onto the other application surface (6, 8), the skin (12) and the support (10) being interposed between said mold parts (2, 4) , characterized in that the first part (2) of the mold comprises means (20) for applying the decorative element (16) against the second mold part (4), said application means ation (20) comprising at least one receiving surface (22) of a decorative element (16) and being movable between a retracted position, wherein said means (20) are disposed in the first mold part (2), and an erected position, wherein said receiving surface (22) is applied against the application surface (8) of said second mold portion (4). 2. Thermoforming mold according to claim 1, characterized in that the receiving surface (22) of the decorative element (16) has a shape substantially complementary to a portion (18) of the application surface ( 8) of the second mold part (4), said part (18) of the application surface (8) receiving and maintaining said decorative element (16) after the application of the decorative element (16) against said portion (18) by the application means (20) in erected position. 3. thermoforming mold according to claim 1 or 2, characterized in that the application means (20) comprise at least one cylinder (28) carrying the receiving surface (22), said cylinder (28) actuating the displacement the receiving surface (22) between the retracted position and the erected position. 4. Thermoforming mold according to any one of claims 1 to 3, characterized in that the receiving surface (22) forms a part of the application surface (6) of the first part (2) mold when the application means (20) are in the retracted position, said receiving surface (22) projecting from said application surface (6) when the application means (20) are in the erected position. 5. Thermoforming mold according to claim 4, characterized in that the application means (20) comprise at least one compensation element (30) having a holding surface (32), said retaining surface (32) salient the receiving surface (22) so as to be flush with the application surface (6) of the first mold part (2) when the application means (20) are in the retracted position. 6. Thermoforming mold according to any one of claims 1 to 3, characterized in that the application surface (6) of the first portion (2) of the mold is retractable, said surface (6) being retracted when the application means (20) are in an erected position and said surface (6) covering the application means (20) when the application means (20) are in the retracted position. 7.- thermoforming mold according to any one of claims 1 to 6, characterized in that it comprises at least two receiving surfaces (22) for receiving each a decorative element (16). 8. A method of producing a part (14) of a motor vehicle, comprising a support (10), a skin (12) covering said support (10) and at least one decorative element (16) disposed on said skin ( 10), by means of a mold (1) according to any one of claims 1 to 7, comprising the following steps: - arranging a decorative element (16) on the receiving surface (22) of the application means (20), - actuating the application means (20) so as to pass them in the erected position and to apply the decorative element (16) against the application surface (8) of the second part (4) of mold, - passing the actuating means (20) in the retracted position, - arranging the support (10) and the skin (12) of the part (14) of the motor vehicle between the first and second mold parts (2 , 4), - bringing the first and second mold parts (2, 4) closer together so as to apply the skin (12) to the support (10) and to the adhering to one another by thermoforming, the decorative element (16) being applied and adhering against the skin (12), - separating the two mold parts (2, 4) and removing the piece (16) of motor vehicle of the mold. 9. A production method according to claim 8, characterized in that an adhesive is applied against both sides of the decorative element (16) so as to adhere the decorative element (16) against the second part ( 4) when the application means (20) pass from the erected position to the retracted position and then adhere the decorative element (16) to the skin (12) when the second mold part (4) is applied against the skin (12) to apply the skin (12) to the support (10). 10. A motor vehicle dashboard panel comprising a support (10), a skin (12) covering said support (10) and at least one decorative element (16) disposed on said skin (12), said panel being obtained by an embodiment according to claim 8 or 9.