Extrusion blow mould, moulding machine and moulding method

Abstract

The invention relates to an extrusion blow-molding manufacturing mold (1) comprising two parts (1a, 1b) comprising at least one first mold segment (3) having a first molding surface (11, 11a, 11b) comprising a plurality of pressing zones (5) arranged to form, by pressing, a fixing zone of at least one inner part (30) inside a parison (20), and a second mold segment (4) having a second molding surface, the second mold segment (4) of a part (1a, 1b) of the mold (1) being movable relative to the associated at least one first mold segment (3, 3a, 3b) of the part (1a, 1b) of the mold (1).

Description

Technical Field

[0001] This invention relates to a mold for manufacturing a hollow plastic tank for motor vehicles by extrusion blow molding based on a preform, the tank including at least one internal component fixed inside the preform during molding of the hollow body. More specifically, the invention relates to a mold comprising two parts including a plurality of mold segments internally defining a mold cavity, the mold cavity including a total molding surface designed to reproduce a predetermined shape of the hollow body to be manufactured.

[0002] The present invention also relates to a molding machine for molding hollow bodies of plastic storage tanks for motor vehicles by extrusion blow molding based on preforms.

[0003] Finally, the present invention relates to a molding method for molding a hollow plastic tank for motor vehicles by extrusion blow molding based on a preform, the tank including at least one internal component fixed inside the preform during molding of the hollow body. Background Technology

[0004] In document WO 2008 / 138869, the applicant describes a mold for manufacturing a fuel tank having internal components or assemblies of internal components. The mold cavity includes a plurality of movable rods, each with a pressing surface at its free end for locally pushing and contacting a molten preform with a region of the internal components, thereby fixing the internal components within the preform by pressing. Another example is described in document US2014 / 265052.

[0005] Because the pressing surface of the movable rod is limited by its cross-section, the more areas of the internal components to be fixed, the more movable rods must be installed. The free end of the movable rod typically has approximately 4000 mm. 2 The pressing surface, which is less than 2% of the total mold area, is used. Using six movable rods reduces it to less than 12% of the total mold area. Similarly, the more internal components the internal component group contains, the more movable rods must be installed. This is unsatisfactory because the mold design becomes more complex and its manufacturing cost increases.

[0006] Furthermore, the applicant observed that at the location where the preform is pushed towards the internal component by the movable rod, the preform material is stretched towards the fixed area, resulting in a reduction in the preform's thickness at the fixed point. This is undesirable because the reduced material thickness at the fixed location can cause insufficient fixation of the internal component. Additionally, the thickness reduction observed at the fixed point is often accompanied by other deformations. These other deformations are unevenness around the fixed material. This is also undesirable because the more deformation the tank undergoes during its manufacture, the worse the mechanical strength of the resulting tank. Clearly, the aforementioned risks are exacerbated by the doubling of the movable rod.

[0007] The applicant also observed that, since the movable rod does not constitute part of the mold cooling circuit, doubling the number of movable rods leads to a decrease in the uniformity of mold cooling temperature. This is unsatisfactory because reduced uniformity of mold cooling temperature can easily cause deformation of the tank during its manufacturing process.

[0008] Another drawback of the aforementioned mold is that doubling the number of movable rods results in doubling the number of movable rod actuation mechanisms, which leads to an increase in the size and complexity of extrusion blow molding machines equipped with such molds.

[0009] Therefore, it can be understood that the manufacturing cost of a storage tank with one (or more) internal components increases as the number of movable rods required to fix the one (or more) internal components increases. Summary of the Invention

[0010] The object of the present invention is particularly to overcome the above-mentioned defects by providing a mold that ensures the manufacture of a storage tank including one (or more) internal components without deformation and at a low cost, independent of the number of fixing devices for one (or more) internal components inside the preform.

[0011] Therefore, the present invention relates to a mold for manufacturing a hollow plastic tank for motor vehicles by extrusion blow molding based on a preform, the tank including at least one internal component fixed inside the preform during molding of the hollow body, the mold including two parts movable relative to each other, the two parts defining a total molding surface internally when closed by abutting each other, the total molding surface being designed to reproduce a predetermined shape of the hollow body to be manufactured, at least one of the parts of the mold including:

[0012] - At least one first mold segment having a first molding surface for molding a first portion of a hollow body to be manufactured, the first molding surface including at least one pressing area configured to form a fixing area for fixing at least one internal component inside the preform by pressing;

[0013] - A second mold segment having a second molding surface for molding a second part of the hollow body to be manufactured;

[0014] The second segment of the mold portion is movable relative to the at least one first segment associated with the mold portion, at least between an intermediate closed position and a final closed position of these portions of the mold, the mold being characterized in that the first molding surface of the mold portion includes a plurality of pressing areas and is configured such that these pressing areas simultaneously form a plurality of fixing areas for fixing at least one internal component inside the preform by pressing.

[0015] Advantageously, according to the invention, the mold allows for the fixing of one or more internal components without the use of multiple movable rods, which are replaced by mold segments of the mold, the molded surfaces of which are large enough to simultaneously press the preform against multiple areas of the internal component to be fixed.

[0016] In addition to cost savings, the invention also allows for the avoidance of localized deformation of the parison material when the parison is brought into contact with the area to be fixed, because the first molding surface extends between different fixing regions for securing one (or more) internal components to the interior of the parison, i.e., the first molding surface specifically includes these different fixing regions. With this arrangement, the material thickness at the location of each fixing region is not reduced, and unevenness of the material around the fixing region is avoided.

[0017] Another advantage of the mold according to the invention is that it allows for the avoidance of increasing the size and complexity of the extrusion blow molding machine equipped with such a mold, regardless of the number of fixed areas and internal components of the future storage tank.

[0018] The invention may also include one or more of the following optional features, used individually or in combination.

[0019] The first molding surface of a portion of the mold can be configured to extend along an outer surface containing a pressing area associated with the portion of the mold. Thus, by means of the respective pressing areas of the first molding surface, and simultaneously according to the plurality of predetermined fixing areas or all fixing areas of the at least one internal component of the portion of the mold, each portion of the first molding surface has a single surface facing the preform in the intermediate closed position to fix the preform.

[0020] The outer surface of the first molding surface of a portion of the mold may include a predetermined margin distance at least around the pressing area associated with that portion of the mold of the at least one internal component, to limit unevenness of the material around each fixed area. It can be understood that the first molding surface includes a larger single surface around the fixed area of ​​the at least one internal component to avoid excessively prominent unevenness of the at least one internal component near the fixed area inside the preform. The predetermined margin distance at least around the pressing area may be between 1 mm and 60 mm.

[0021] The outer surface of the first molding surface of a portion of the mold is preferably at least 30% of the total molding surface. Therefore, according to this embodiment, if only one portion of the mold or two portions of the mold include at least one first molding segment, the total percentage of said at least one first molding segment is at least 30% or at least 60% of the total molding surface, respectively. However, without departing from the scope of the invention, the outer surface of the first molding surface of a portion of the mold can be between 20% and 40% of the total molding surface, i.e., for example, equal to 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%.

[0022] Thus, according to the first embodiment, each part of the mold may include at least one first mold segment and a second mold segment, and according to the second embodiment, only one part of the mold includes at least one first mold segment and a second mold segment. Typically, in the second embodiment, the first part of the mold may include at least one first mold segment and a second mold segment, while the second part of the mold may include a single mold segment of a single unit.

[0023] In the final closed position, each part of the mold is preferably surrounded by at least one first mold segment, which is associated with that part of the mold. Thus, the at least one internal component is completely enclosed within the hollow body.

[0024] In a first embodiment, each portion of the mold may include at least one first segment, configured to press the preform against the same at least one internal component to form at least two distinct fixing regions for securing the same at least one internal component inside the preform during molding of the hollow body. It is understood that at least one pressing region of the at least one first segment of the first portion of the mold may thereby be aligned, i.e., vertically aligned, with at least a portion of the pressing region of the at least one first segment of the second portion of the mold to simultaneously secure two substantially opposing regions of the internal component to two separate regions inside the preform. Thus, the first segment of the mold acts as a vise-like clamping mechanism for securing the at least one internal component.

[0025] Regardless of the implementation, the at least one first mold segment of the mold portion may include at least one suction element designed to draw the parison during molding of the hollow body, as particularly in one of the pressing areas. This allows the parison to adhere better to the first molding surface, which also avoids localized deformation of the parison.

[0026] The at least one first mold segment of the mold may include an element selected from a part-holding element, a heating element, and a combination of holding and heating elements, said part being or not said at least one internal component, which is intended to be molded together with the first portion of the hollow body. Thus, the part can be attached to the first portion of the hollow body during molding. In one example, the holding element is a clamp or suction element, and the heating element is an electric heater. In one example, the part is a metal attachment or a fiber reinforcement. In another example, the heating element is a hydraulic heater.

[0027] The at least one first section of the mold may include a blowing tool designed to introduce pressurized gas into the interior of the preform. In one example, the blowing tool is a blowing needle. This arrangement allows for the avoidance of arranging the blowing tool in a second section of the mold when it is required, which would result in reduced evaporation and mechanical properties of the obtained tank, as well as increased risk of the tank undergoing deformation during its manufacture.

[0028] The at least one segment of the mold may include a first cooling device designed to cool the first part of the hollow body. This allows any deformation of the first part of the hollow body during its manufacturing process to be avoided.

[0029] The second section of the mold may include a second cooling device designed to cool the second part of the hollow body. This allows for the prevention of any deformation of the second part of the hollow body during its manufacturing process.

[0030] Advantageously, the first and second cooling devices belong to the same cooling circuit. This allows for the homogenization of the mold temperature.

[0031] The at least one first segment of the mold may include multiple first segments to improve the modularity of the mold.

[0032] The present invention also relates to a molding machine for molding hollow bodies of plastic storage tanks for motor vehicles by extrusion blow molding based on preforms, characterized in that the machine includes the mold as described above. Thus, the molding machine benefits from all the advantages associated with the mold.

[0033] Finally, the present invention relates to a molding method for molding a hollow plastic storage tank for motor vehicles by extrusion blow molding based on a preform, the storage tank including at least one internal component fixed inside the preform during molding of the hollow body, the molding method being characterized in that the method includes the following steps:

[0034] a) Introducing the at least one internal component and the molten preform into a mold that opens into two parts, such that the at least one internal component is surrounded by the preform, and at least one part of the mold includes at least one first mold segment and a second mold segment, which respectively internally define the first mold surface and the second mold surface of the total molding surface of the mold.

[0035] b) The at least one first mold segment of the moving mold portion is such that the mold is in an intermediate closed position, in which the at least one first mold segment of the mold portion presses the preform against the at least one internal component to fix the at least one internal component inside the preform, the first molding surface being configured to simultaneously form multiple fixed areas of the at least one internal component inside the preform by pressing.

[0036] c) Move a second segment of the mold portion relative to the at least one first segment of the mold portion such that the mold is in a final closed position, in which the two portions of the mold are closed against each other, while internally defining a total molded surface intended to reproduce the predetermined shape of the hollow body to be manufactured;

[0037] d) Blow molding of the preform is achieved by using pressurized gas to make the preform adhere tightly to the overall molding surface of the mold;

[0038] e) Open the mold to remove the manufactured hollow body.

[0039] The molding method according to the invention preferably uses an extruded preform. According to the invention, each internal component is surrounded by a preform either by extruding the preform around each internal component or by inserting each internal component into the preform. In the case of inserting the internal components into the preform, the preform can be placed into an open mold by a robot.

[0040] A stretchable extruded preform allows for the insertion of internal components without the risk of collision with the preform, which can be achieved through suitable means. In one example, the molding method according to the invention uses a tool that allows the preform to be stretched to maintain its open position, such as a tool of the type 6 shown in document WO 2008 / 138869. This tool may consist of clamps, pincers, or claws capable of gripping the edges of the preform and maintaining them spaced apart. The tool may be robotically controlled.

[0041] The invention may also include one or more of the following optional features, used individually or in combination.

[0042] Preferably, pressurized gas is introduced into the preform between steps a) and b) to achieve pre-blow molding of the preform. This gas introduction can be achieved according to step b of document WO 2008 / 138869, particularly to expand the preform while ensuring uniform preform thickness. Gas with a lower pressure than in step d) can be introduced in various ways known to those skilled in the art. As examples without limitation, the gas introduction for this pre-blow molding can be achieved using a blowing tool for step d), a special tool mounted on the mold, a hollow rod for supporting internal components, or a nozzle included in the extrusion head of the preform.

[0043] In step b), the at least one internal component can be fixed inside the blank by welding, riveting or mechanical anchoring. Attached Figure Description

[0044] Other features and advantages of the invention will become clear from the following illustrative and non-limiting description with reference to the accompanying drawings, in which:

[0045] - Figure 1 This is a partial perspective side view of a mold according to a first embodiment of the present invention, the mold being in the open position;

[0046] - Figure 2 This is a partial perspective side view of a mold according to a first embodiment of the present invention, the mold being in the middle closed position;

[0047] - Figure 3 This is a front view of a portion of a mold according to a first embodiment of the present invention, the mold being in the open position;

[0048] - Figure 4 This is a perspective view of a portion of the mold according to the first embodiment of the present invention.

[0049] The mold is in the open position;

[0050] - Figures 5 to 7 This is a schematic cross-sectional view of a first embodiment of a mold according to the present invention, the mold being in successive different positions;

[0051] - Figures 8 to 10 This is a schematic cross-sectional view of a second embodiment of a mold according to the present invention, the mold being in successive different positions;

[0052] - Figure 11 This is a cross-sectional view showing a portion of the mold according to the invention for the suction element;

[0053] - Figure 12 This is a cross-sectional view showing a portion of the mold of the blowing tool according to the invention;

[0054] - Figure 13 This is a cross-sectional view of a portion of the mold according to the invention, showing the holding element in an inactive state;

[0055] - Figure 14 This is a cross-sectional view of a portion of the mold according to the invention, showing the holding element in the activated state;

[0056] - Figure 15 This is a cross-sectional view of a portion of the mold according to the invention, showing the combined holding and electric heating element in an inactive state;

[0057] - Figure 16 This is a cross-sectional view of a portion of the mold according to the invention, showing the combined holding and hydraulic heating elements in an inactive state;

[0058] - Figure 17 This is a cross-sectional view showing a portion of the mold according to the invention for the cooling device. Detailed Implementation

[0059] In different accompanying drawings, the same or similar elements have the same reference numerals, and may be accompanied by subscripts. Therefore, their structure and function are not always described repeatedly.

[0060] Throughout this text, orientation refers to the orientation of the accompanying figures. Specifically, the terms "up," "down," "left," "right," "above," "below," "forward," and "backward" generally refer to directions relative to the figures shown in the accompanying illustrations.

[0061] "Tank" refers to a sealed tank suitable for storing fluids under various variable usage and environmental conditions. The tank manufactured using the mold according to the invention has walls made of plastic. The tank walls have an inner surface and an outer surface. The inner surface is the surface facing the internal volume of the tank, while the outer surface is the surface facing the external volume of the tank.

[0062] "Plastic" refers to any material that includes at least one synthetic resin polymer. All types of plastics are suitable. Very suitable plastics belong to the thermoplastic category.

[0063] "Thermoplastic material" refers to any thermoplastic polymer, including thermoplastic elastomers, and mixtures thereof. The term "polymer" refers to both homopolymers and copolymers (especially binary or ternary copolymers). Examples of such copolymers, without limitation, include random copolymers, sequential copolymers, block copolymers, and graft copolymers.

[0064] All types of thermoplastic copolymers or polymers with melting temperatures below their decomposition temperatures are suitable. Synthetic thermoplastic materials with a melt range distribution of at least 10 degrees Celsius (10°C) are particularly suitable. As examples of such materials, there are materials with polydisperse molecular weights.

[0065] In particular, polyolefins, thermoplastic polyesters, polyketones, polyamides, and copolymers thereof can be used. Mixtures of polymers or copolymers can also be used, as can mixtures of polymeric materials with inorganic, organic, and / or natural fillers (e.g., but not limited to carbon, salts and other inorganic derivatives, natural or polymeric fibers, etc.). Multilayer structures consisting of stacked and linked layers comprising at least one of the aforementioned polymers or copolymers can also be used.

[0066] One commonly used polymer is polyethylene. Excellent results have been obtained using high-density polyethylene (HDPE).

[0067] In one example, the tank manufactured using the mold according to the invention is a fuel tank comprising a multi-layered structure, including at least one thermoplastic material layer and at least one additional layer, which may advantageously be made of a liquid- and / or gas-barrier material. Preferably, the nature and thickness of the barrier layer are selected to maximally limit the permeability of liquids and gases in contact with the tank walls. Preferably, the layer is based on a barrier material, i.e., a fuel-impermeable resin, such as EVOH (partially hydrolyzed ethylene-vinyl alcohol copolymer). Alternatively, the tank may undergo a surface treatment (fluorination or vulcanization) intended to make it fuel-impermeable.

[0068] A "preform" refers to a single preform, which is usually extruded and roughly tubular. This preform is intended to form the tank wall after molding. "After molding" means after the operation of shaping the molten preform into the required shape and size to obtain the tank using a mold.

[0069] "Internal components" refer to components that perform functions required within a tank, such as ventilation, reinforcement, fluid pumping, fluid level measurement, and noise reduction related to wave-like phenomena in the fluid within the tank. In one example, an internal component is a reinforcing column connecting opposite sides of the tank's inner surface.

[0070] The “first mold segment” and “second mold segment” of a mold refer to the first and second molding elements located in at least one part of the mold, respectively.

[0071] "First molding surface" refers to the inner surface of at least one first segment of the mold, which defines the molding space of a first portion of the hollow body. The inner surface includes a bottom and a protrusion projecting from the bottom.

[0072] "Second molding surface" refers to the inner surface of the second section of the mold, which defines the molding space of the second part of the hollow body. The inner surface includes a bottom and a protrusion extending from the bottom.

[0073] "The first molding surface is at least 30% of the total molding surface" means that the area of ​​the first molding surface is greater than or equal to 30% of the total molding surface area, while being strictly less than 100% of the total molding surface area.

[0074] Advantageously, the sum of the molding surfaces of the two molding parts equals the total molding surface. Therefore, these two parts of the mold are sufficient to manufacture the entire hollow tank.

[0075] "Plastic welding" refers to a collection of techniques for welding two thermoplastic material parts. Exemplarily, where the materials of the internal components and the preform are compatible with welding, plastic welding can be achieved by applying contact pressure at the boundary between the interior of the molten preform and the area to be fixed of the at least one internal component through pressing in each pressing area of ​​the at least one first segment of the mold. To facilitate plastic welding, the area to be fixed of the at least one internal component is preferably preheated to soften and melt.

[0076] "Riveting" refers to a collection of techniques used to fix an internal component to a preform by pressing through each pressing area of ​​at least one first segment of the mold, causing a portion of the preform to creep into a cutout of an internal component, particularly when the materials of the internal component and the preform are incompatible with welding. After the preform hardens, the riveting prevents the component from retracting relative to the hardened preform by means of the shape of the cutout. (See document WO 2007 / 090453). Figure 1 and Figure 2 Examples of the hardened shape of the blank and the hollowed-out part of the component are marked with 5 and 3 respectively.

[0077] "Mechanical anchoring" refers to a collection of techniques used to fix an internal component to the preform by pressing through each pressing area of ​​at least one first segment of the mold, causing a portion of the internal component to creep into the preform, particularly when the materials of the internal component and the preform are incompatible with welding. After the preform hardens, this mechanical anchoring prevents the internal component from retracting relative to the hardened preform by means of the shape of the internal component entering the preform. (See document EP1211196). Figure 10 Examples of the hardened shape of the blank and the entry portion of the internal components are marked with 116 and 102 respectively.

[0078] Except as otherwise specified in this specification, extrusion blow molding components known to those skilled in the art are employed in a conventional manner. Therefore, conventional components such as supports for internal components (e.g., rods), blowing devices, preform manufacturing apparatus, preform separation and guiding devices around internal components, or preform sealing devices for performing pre-blow molding, such as those described in document WO 2008 / 138869 (see in particular reference numerals 3, 6, 7, and 7' in the figures), are not always described in this specification.

[0079] The following embodiments are examples. Although one or more embodiments are mentioned in this specification, it is not necessarily true that every mention relates to the same embodiment, or that a feature applies only to a single embodiment. Simple features of different embodiments may also be combined and / or interchanged to provide other embodiments.

[0080] In this specification, certain elements or parameters may be indexed, such as a first element or a second element, a first parameter and a second parameter, or a first standard and a second standard, etc. In this case, this involves a simple index for distinguishing and naming closely related but not identical elements, parameters, or standards. This index does not imply a priority of one element, parameter, or standard relative to another, and such names can be easily interchanged without exceeding the scope of this specification. This index also does not imply a chronological order, for example, for evaluating such and such standards.

[0081] Figure 1 and Figure 2 A mold 1 is shown for manufacturing a hollow body 10 of a plastic storage tank for motor vehicles by extrusion blow molding based on a preform 20, the storage tank including at least one internal component 30 fixed inside the preform during molding of the hollow body. More specifically, Figure 1 The mold 1 is shown in the open position. Figure 2 The mold is shown in the intermediate closed position. As described below, the hollow body 10 is in the final closed position of the mold 1 (in... Figure 7 and Figure 10 (As shown in the image) was obtained.

[0082] Mold 1 includes two parts 1a and 1b that are movable relative to each other, when they are closed by abutting each other (as in...). Figure 7 and Figure 10 (Visible in the middle) They internally define the total molding surface or cavity 2, which is intended to reproduce the predetermined shape of the hollow body 10 to be manufactured.

[0083] According to the present invention, at least one of the portions 1a and 1b of the mold 1 includes:

[0084] - At least one first molded section 3a, 3b having first molding surfaces 11, 11a, 11b for molding a first portion of the hollow body 10 to be manufactured, the first molding surfaces 11, 11a, 11b including at least one pressing area 5, the pressing area 5 being configured to form the interior of the preform 20 and the fixing area of ​​the at least one internal component 30 by pressing;

[0085] - Second module segments 4, 4a, 4b, having second molding surfaces 12, 12a, 12b for molding a second portion of the hollow body 10 to be manufactured.

[0086] The second mold segments 4, 4a, 4b of portions 1a, 1b of mold 1 are capable of being closed at least in at least one intermediate position relative to at least one first mold segment 3a, 3b associated with that portion 1a, 1b of mold 1 (in... Figure 2 , Figure 6 and Figure 9 (as shown in the diagram) and the final closed positions of portions 1a and 1b of mold 1 (in...) Figure 7 and Figure 10 (as shown in the image) move between.

[0087] Advantageously, according to the invention, such as Figure 3 and Figure 4 As shown, the first molding surfaces 11, 11a, 11b of portions 1a and 1b of the mold 1 include a plurality of pressing areas 5, and are configured such that these pressing areas 5 simultaneously form a plurality of fixed areas of the at least one internal component 30 inside the preform 20 by pressing.

[0088] like Figure 3 As shown, the first molding surfaces 11, 11a, 11b of portions 1a, 1b of mold 1 can thus be configured as such external surfaces Sc (in) along the pressing areas 5 of the portions 1a, 1b of mold 1, and even all pressing areas 5 associated with the portions 1a, 1b of mold 1. Figure 3 (Extended as a dotted line). Of course, in Figure 3 The outer surface Sc, which is shown as a dashed line, is merely an example. Without departing from the scope of this invention, the pressing areas 5 may be interconnected by curved sections instead of straight sections.

[0089] Therefore, in the middle closing position (in) Figure 2 , Figure 6 and Figure 9As shown in the figure, each portion 1a, 1b of the first molding surfaces 11, 11a, 11b has a unique surface facing the preform 20, so as to fix the preform 20 by means of the respective pressing areas 5 of the first molding surfaces 11, 11a, 11b, and simultaneously according to the plurality of predetermined fixing areas or all of the fixing areas of the at least one internal component 30 of the portion 1a, 1b of the mold 1.

[0090] The outer surface Sc of each first molding surface 11, 11a, 11b may include a predetermined distance demarcation at least around the pressing areas 5 associated with that portion of the mold 1 of the at least one internal component 30, to limit unevenness of the material around each fixed area. This predetermined distance demarcation at least around the pressing areas 5 may be between 1 mm and 60 mm. Of course, the predetermined distance demarcation need not be constant relative to each pressing area 5 or between each pressing area. Figure 3 This illustrates an example of a first surface 11, whose predetermined edge surrounds a dashed circumscribed surface Sc. Another example is not constant, but the invention is not limited thereto.

[0091] The outer surfaces of the first molding surfaces 11, 11a, 11b of portions 1a and 1b of mold 1 are preferably at least 30% of the total molding surface. Therefore, according to this embodiment, if a single portion 1a or 1b of mold 1, or two portions 1a and 1b of mold 1, include at least one first molding segment 3, 3a, 3b, the total percentage of said at least one first molding segment 3, 3a, 3b of mold 1 is at least 30% or 60% of the total molding surface, respectively. However, without departing from the scope of the invention, the outer surface Sc of the first molding surfaces 11, 11a, 11b of portions 1a, 1b of the mold may be between 20% and 40% of the total molding surface, i.e., equal to, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40%.

[0092] Figures 5 to 7 A molding machine 100 is shown for molding a hollow body 10 of a plastic storage tank for a motor vehicle by extrusion blow molding based on a preform 20. The machine 100 includes the mold 1 described above according to the first embodiment. Figure 5 The image shows mold 1 in the open position (open mold 1). Figure 6 The mold 1 is shown in the middle closed position. Figure 7 The mold is shown in its final closed position.

[0093] In the intermediate closed position, at least one first mold segment 3, 3a, 3b of mold 1 protrudes relative to the second mold segment 4, 4a, 4b of mold 1. In the final closed position, the second mold segments 4, 4a, 4b of mold 1 surround the at least one first mold segment 3, 3a, 3b of mold 1 that has not changed position, such that the first molding surfaces 11, 11a, 11b and the second molding surfaces 12, 12a, 12b engage to form the total molding surface or mold cavity 2.

[0094] The at least one first mold segment 3, 3a, 3b of the mold 1 includes pressing areas 5, which are configured to press the preform 20 against the at least one internal component 30 to form at least two different fixing areas of the same at least one internal component 30, thereby fixing the same at least one internal component 30 inside the preform 20 when molding the hollow body 10.

[0095] Advantageously, each pressing region 5 is configured to allow welding, riveting, or mechanical anchoring to secure the at least one internal component 30 within the preform 20 during molding of the hollow body 10. Each pressing region may thereby include geometry, mechanical features, and / or materials designed to facilitate welding, riveting, or mechanical anchoring. As a non-limiting example, the pressing region 5 may include a flat surface of material having a melting temperature higher than the melting temperature of the preform and the area of ​​the internal component to be fixed, such that at least one weld-fixed area is formed between the preform and the area of ​​the internal component to be fixed by pressing the pressing region. Of course, in addition to or instead, the pressing region may also include protrusions designed to facilitate riveting and / or cutouts designed to facilitate mechanical anchoring.

[0096] The first part 1a of the mold 1 includes at least one first mold segment 3a, and the second part 1b of the mold 1 includes at least one additional first mold segment 3b. The at least one first mold segment 3a of the mold 1 is movable relative to the at least one additional first mold segment 3b of the mold 1 between an open position and an intermediate closed position. Each part 1a, 1b of the mold 1 includes at least one first mold segment 3a, 3b for movement from the open position to the intermediate closed position and from the intermediate closed position to the open position.

[0097] The first part 1a of the mold 1 includes a second mold segment 4a, and the second part 1b of the mold 1 includes another second mold segment 4b. The second mold segments 4a and 4b of the mold 1 are movable relative to each other between an intermediate closed position and a final closed position. Each second mold segment 4a and 4b of the mold 1 includes a second actuator 7 for moving from the intermediate closed position to the final closed position and from the final closed position to the intermediate closed position.

[0098] exist Figure 11 In the example shown, the at least one first mold segment 3 of the mold includes at least one suction element 14b in at least one pressing area 5, designed to draw the preform 20 during molding of the hollow body 10. At least one suction element 14a is also visible at the bottom of the first molding surface 11. Multiple suction elements 14a are interconnected and communicate with a suction device (not shown), such as a vacuum machine, via a connector 14c. This allows the preform 20 to fit more closely to the first molding surface 11, which also prevents localized deformation of the preform 20.

[0099] exist Figures 13 to 16 In the example shown, the at least one first segment 3 of the mold 1 includes an element selected from the following components of part 31: a holding element 15; heating elements 16, 16'; and a combination of holding 15 and heating elements 16, 16'. Part 31 is intended to be molded together with a first portion of the hollow body 10; it may or may not be the at least one internal component 30. The holding element may thus be a clamp 15a or a suction element. Figures 13 to 14 In the example, with the help of actuator 15b, clamp 15a can be moved from the open position ( Figure 13 ) to the closed position ( Figure 14 ), so as to press the blank 20 against the part 31, as described, for example, in document EP3946905. Figure 15 In the example, the heating element 16 is an electric heater 16a, while Figure 16 In one example, the heating element 16' is a hydraulic heater 16'a to locally reheat at least the preform 20. According to one example, part 31 is a metal attachment or a fiber reinforcement.

[0100] exist Figure 12 In the example shown, the at least one first section 3 of the mold 1 includes an air blowing tool 13 designed to introduce pressurized gas into the interior of the preform 20. As in Figure 12 As can be seen, the air blowing tool 13 includes an air blowing needle 13a capable of penetrating the preform 20 to perform step d). It is also visible that the needle 13a is mounted to be movable relative to the first molding surface 11 by means of an actuator 13b, to transition from a position retracted into the at least one first mold segment 3 to a position extending beyond the bottom of the first molding surface 11, and from a position extending beyond the bottom of the first molding surface 11 to a position retracted into the at least one first mold segment 3.

[0101] exist Figure 17In the example shown, at least one first segment 3 and / or second segment 4 of part 1a of mold 1 includes a cooling device 17 for cooling a portion of the hollow body 10. The at least one first segment 3a of mold 1 includes a cooling element 17a for cooling a first portion of the hollow body 10. The second segment 4a of mold 1 includes a cooling element 17b for cooling a second portion of the hollow body 10. Of course, cooling elements 17a and 17b may belong to the same hydraulic circuit as the cooling device 17.

[0102] Figures 5 to 7 Also shown is a method for molding a hollow body 10 of a plastic storage tank for motor vehicles by extrusion blow molding based on a preform 20, the storage tank including at least one internal component 30 fixed to the interior of the preform 20 during molding of the hollow body 10, characterized in that the method includes the following steps:

[0103] a) Introduce the at least one internal component 30 and the preform 20 in a molten state into a mold 1 that is opened into two parts 1a and 1b, such that the at least one internal component 30 is surrounded by the preform 20, wherein at least one part 1a and 1b of the mold 1 includes at least one first mold segment 3 and a second mold segment 4, which respectively internally define a first mold surface 11 and a second mold surface 12 of the total molding surface of the mold 1.

[0104] b) Move at least one first mold segment 3 of portions 1a and 1b of the mold 1 so that the mold 1 is in an intermediate closed position, in which the at least one first mold segment 3 presses the preform 20 against the at least one internal component 30 to fix the at least one internal component 30 inside the preform 20, the first molding surface 11 being configured to simultaneously form multiple fixed areas of the at least one internal component 30 inside the preform 20 by pressing;

[0105] c) Move the second segment 4 of the portion 1a, 1b of the mold 1 relative to at least one first segment 3 of the portion 1a, 1b of the mold 1, so that the mold 1 is in the final closed position, in which the two portions 1a, 1b of the mold 1 are in a closed position.

[0106] 1b is closed against each other, while internally defining the total molding surface intended to reproduce the predetermined shape of the hollow body 10 to be manufactured;

[0107] d) Blow molding of the preform 20 is achieved by pressing the preform 20 tightly against the overall molding surface of the mold 1 using pressurized gas;

[0108] e) Open mold 1 to remove the manufactured hollow body 10.

[0109] Preferably, pressurized gas is introduced into the preform 20 between steps a) and b) to perform pre-blow molding of the preform 20. This gas introduction can be performed according to step b) of document WO 2008 / 138869 to cause the preform to expand, while simultaneously homogenizing its thickness. Gas with a lower pressure than in step d) can be introduced in various ways known to those skilled in the art. As a non-limiting example, the gas introduction for pre-blow molding can be achieved using a blowing tool for performing step d), a special tool mounted on the mold, a hollow rod for supporting internal components, or a nozzle included in the extrusion head of the preform.

[0110] Advantageously, in step b), the at least one internal component 30 is secured inside the blank 20 by welding, riveting or mechanical anchoring.

[0111] In the final closed position of mold 1, blow molding of step d) is performed under a blow molding pressure of approximately 10 bar (1 MPa). In order to ensure that the blow molding pressure is not applied to the actuator 6 through the at least one first mold segment 3 of the mold, the force is applied to the support plate 9 connected to the molding machine 100.

[0112] Figures 8 to 10 A second embodiment of mold 1 is shown. The second embodiment differs from the first embodiment in that the second portion 1b of mold 1 forms a single-unit mold segment 8. In other words, relative to... Figures 5 to 7 The first implementation method, Figures 8 to 10 The single-unit module segment 8 replaces at least one first module segment 3b and the second module segment 4b of part 1b of mold 1. This allows for simplification of mold 1 by reducing the number of parts required to construct mold 1.

[0113] This invention is not limited to the embodiments and variations described, and other embodiments and variations will be apparent to those skilled in the art. Thus, the embodiments described above are merely examples. Although one or more embodiments are mentioned in this specification, this does not necessarily mean that every mention relates to the same embodiment, or that a feature is applicable only to a single embodiment. Simple features of different embodiments may also be combined and / or interchanged to provide other embodiments. As a non-limiting example, in a second embodiment, it is conceivable to use a single actuator 7 to move the second segment 4a toward the single segment 8 (which is therefore stationary) to further simplify the molding machine 100. Similarly, although the figures show a single first segment 3a, 3b of portions 1a, 1b of the mold 1, it is conceivable that the at least one segment 3a, 3b of the mold 1 may include multiple first segments 3a, 3b, such as two, three, four, five, six, seven, eight, nine, or ten first segments 3a, 3b.

[0114] List of reference numerals

[0115] 1: Mold

[0116] 1a: The first part of the mold

[0117] 1b: The second part of the mold

[0118] 2: Mold cavity

[0119] 3, 3a, 3b: The first section of the mold

[0120] 4, 4a, 4b: The second section of the mold

[0121] 5: Pressing area

[0122] 6: First actuator

[0123] 7: Second actuator

[0124] 8: Single-unit module

[0125] 9: Support plate

[0126] 10: Hollow body

[0127] 11, 11a, 11b: First molded surfaces

[0128] 12, 12a, 12b: Second molded surfaces

[0129] 13: Inflatable tool

[0130] 13a: Inflatable needle

[0131] 13b: Actuator for the air-blowing needle

[0132] 14: Suction element

[0133] 14a: Suction element at the bottom

[0134] 14b: Suction element in pressing area 5

[0135] 14c: Connector for connection to a suction device

[0136] 15: Holding element

[0137] 15a: Clamps

[0138] 15b: Actuator

[0139] 16, 16': Heating element

[0140] 16a: Electric heater

[0141] 16b: Hydraulic heater

[0142] 17: Cooling equipment

[0143] 17a: Cooling element of the first module section 3a

[0144] 17b: Cooling element of second module 4a

[0145] 20: Parison

[0146] 30: Internal components

[0147] 31: Parts

[0148] 100: Extrusion blow molding machine

Claims

1. A mold (1) for manufacturing a hollow body (10) of a plastic storage tank for a motor vehicle by extrusion blow molding based on a preform (20), the storage tank including at least one internal part (30) fixed inside the preform (20) during molding of the hollow body (10), the mold (1) including two parts (1a, 1b) movable relative to each other, which internally define a total molding surface intended to reproduce a predetermined shape of the hollow body (10) to be manufactured when the two parts are closed abutting each other in a final closed position, at least one of the parts (1a, 1b) of the mold (1) comprising: - At least one first molded segment (3, 3a, 3b) having a first molding surface (11, 11a, 11b) for molding a first portion of the hollow body (10) to be manufactured. - A second molded section (4, 4a, 4b) having a second molding surface (12, 12a, 12b) for molding a second portion of the hollow body (10) to be manufactured, and movable relative to at least one of the associated first molded sections (3, 3a, 3b) of the portion (1a, 1b) of the mold (1), at least between an intermediate closed position and a final closed position of the portion (1a, 1b) of the mold (1), The mold is characterized in that the first molding surface (11, 11a, 11b) of the portion (1a, 1b) of the mold (1) includes a plurality of pressing areas (5) and is configured such that the plurality of pressing areas (5) simultaneously form a plurality of fixed areas of the at least one internal component (30) inside the blank (20) by pressing, the pressing being generated by the at least one first mold segment (3, 3a, 3b) moving to the intermediate closed position of the portion (1a, 1b) of the mold (1).

2. The mold (1) as described in claim 1, wherein, The first molding surfaces (11, 11a, 11b) of the portions (1a, 1b) of the mold (1) are configured to extend along the outer surface containing the pressing area (5) associated with the portions (1a, 1b) of the mold (1).

3. The mold (1) as described in claim 2, wherein, The outer surface of the first molding surface (11, 11a, 11b) of the portion (1a, 1b) of the mold (1) includes a predetermined marginal distance around the pressing area (5) of the at least one internal component (30) associated with the portion (1a, 1b) of the mold (1) to limit the unevenness of the material around each fixed area.

4. The mold (1) as described in claim 3, wherein, The predetermined boundary distance around the fixed area is at least between 1 mm and 60 mm.

5. The mold (1) as described in claim 2, wherein, The outer surface of the first molding surface (11, 11a, 11b) of the portion (1a, 1b) of the mold (1) is at least 30% of the total molding surface.

6. The mold (1) as described in any one of claims 1 to 5, wherein, Each part (1a, 1b) of the mold (1) includes at least one first mold segment (3, 3a, 3b) and a second mold segment (4, 4a, 4b).

7. The mold (1) as described in claim 6, wherein, Each part (1a, 1b) of the mold (1) includes at least one first segment (3, 3a, 3b) of the mold (1), which is configured to press the preform (20) against the same at least one internal component (30) to form at least two different fixing regions of the same at least one internal component (30) to fix the same at least one internal component (30) inside the preform (20) when molding the hollow body (10).

8. The mold (1) as described in any one of claims 1 to 5, wherein, Only one of the portions (1a, 1b) of the mold (1) includes at least one first segment (3, 3a, 3b) and a second segment (4, 4a, 4b).

9. The mold (1) as described in any one of claims 1 to 5, wherein, In the final closed position, at least one first segment (3, 3a, 3b) of each part (1a, 1b) of the mold (1) is surrounded by a second segment (4, 4a, 4b) associated with that part (1a, 1b) of the mold (1).

10. The mold (1) as described in any one of claims 1 to 5, wherein, The at least one first segment (3, 3a, 3b) of the portion (1a, 1b) of the mold (1) includes at least one suction element (14a, 14b) designed to suction the preform (20) when molding the hollow body (10).

11. The mold (1) as described in any one of claims 1 to 5, wherein, The at least one first segment (3, 3a, 3b) of the portion (1a, 1b) of the mold (1) includes an element selected from a holding element (15, 15a), a heating element (16, 16', 16a, 16'a), and a combination element of holding and heating, which is intended to be molded together with the first portion of the hollow body (10).

12. The mold (1) as described in any one of claims 1 to 5, wherein, The at least one first mold segment (3, 3a, 3b) of the portion (1a, 1b) of the mold (1) includes an air blowing tool (13, 13a) designed to introduce pressurized gas into the interior of the preform (20).

13. The mold (1) as described in any one of claims 1 to 5, wherein, The at least one first segment (3, 3a, 3b) and / or the second segment (4, 4a, 4b) of the portion (1a, 1b) of the mold (1) include cooling devices (17, 17a, 17b) designed to cool the portion of the hollow body (10).

14. The mold (1) as described in any one of claims 1 to 5, wherein, The at least one first segment (3, 3a, 3b) of the portion (1a, 1b) of the mold (1) includes a plurality of first segments (3, 3a, 3b).

15. The mold (1) as described in any one of claims 1 to 5, wherein, The multiple pressing areas (5) of the first molding surface (11, 11a, 11b) are configured to form at least two internal parts (30) inside the preform (20) by pressing.

16. A molding machine (100) for molding a hollow body (10) of a plastic storage tank for a motor vehicle by extrusion blow molding based on a preform, characterized in that, The machine includes a mold (1) as described in any one of claims 1 to 15.

17. A molding method for molding a hollow body (10) of a plastic storage tank for a motor vehicle by extrusion blow molding based on a preform (20), the storage tank including at least one internal component (30) fixed inside the preform (20) during molding the hollow body (10), the molding method being characterized in that the method includes the following steps: a) The at least one internal component (30) and the preform (20) in a molten state are introduced into a mold (1) that is opened into two parts (1a, 1b) such that the at least one internal component (30) is surrounded by the preform (20), and at least one part (1a, 1b) of the mold (1) includes at least one first mold segment (3) and a second mold segment (4), which respectively internally define a first mold surface (11) and a second mold surface (12) of the total molding surface of the mold (1). b) Move at least one first mold segment (3) of a portion (1a, 1b) of the mold (1) to place the mold (1) in a middle closed position, wherein the at least one first mold segment (3) of a portion (1a, 1b) of the mold (1) presses the preform (20) against the at least one internal component (30) to fix the at least one internal component (30) inside the preform (20), wherein the first molding surface (11) includes a plurality of pressing areas (5) and is configured such that the plurality of pressing areas (5) simultaneously form a plurality of fixed areas of the at least one internal component (30) inside the preform (20) by pressing; c) Move the second segment (4) of the portion (1a, 1b) of the mold (1) relative to the at least one first segment (3) of the portion (1a, 1b) of the mold (1) so that the mold (1) is in a final closed position, in which the two portions (1a, 1b) of the mold (1) are closed against each other, while defining a total molding surface inside that is intended to reproduce the predetermined shape of the hollow body (10) to be manufactured; d) Blow molding of the preform (20) is achieved by using pressurized gas to make the preform (20) adhere tightly to the overall molding surface of the mold (1); e) Open the mold (1) to remove the manufactured hollow body (10).

18. The molding method as described in claim 17, wherein, Between step a) and step b), pressurized gas is introduced into the preform (20) to perform pre-blow molding of the preform (20).

19. The molding method as described in claim 17 or 18, wherein, In step b), the at least one internal component (30) is fixed inside the blank (20) by welding, riveting or mechanical anchoring.

Images