FR3088024A1 - Method for manufacturing, by molding, a lens for a lighting or signaling optical unit for a vehicle - Google Patents

Abstract

The present invention relates to a method of manufacturing by molding an ice for a lighting or signaling unit for a vehicle, characterized in that it successively comprises the steps of fitting at least one interchangeable insert (I1, I1 ', I2, I2') in at least one corresponding housing (41A, 41B) formed on the punch (41) of a movable part (40) of a mold, for displacement of said movable part (40) so that the latter closes on a first fixed part (50) of said mold in which is formed a first matrix (51), for injecting a first translucent thermoplastic polymer into a molding cavity (CM1) delimited by said punch (41 ) and said first die (51) so as to constitute at least a first portion of said glass, and withdrawal of said movable part (40) away from said first fixed part (50) of the mold.

Description

DESCRIPTION

Title of the invention: Method of manufacturing by molding a lens of an optical lighting or signaling unit for a vehicle.

Field of the invention

The present invention relates generally to the field of lighting and signaling devices for motor vehicles.

It relates in particular to a method of manufacturing by molding an ice for a lighting or signaling unit for a vehicle. It also relates to a pair of ice creams obtained by such a process.

Prior art

These last years have seen the spectacular development of LED technology (for "Light Emitting Diode" in English translating into French by light emitting diode) in many fields and in particular in that of the automobile.

This lighting technology has many advantages compared to conventional halogen bulbs.

Firstly, LED optical units have the advantage of having a markedly extended lifespan of up to several tens of thousands of hours so that they no longer require any maintenance during the entire lifespan of 'a vehicle.

On the other hand, their energy consumption is significantly lower compared to halogen modules (around 60%) which allows to have a positive impact on fuel consumption and carbon dioxide emissions.

Furthermore, the LED modules have a higher light intensity while emitting less dazzling white light for other road users.

Finally, these offer car manufacturers almost endless possibilities in terms of shapes and design allowing them to stand out from the competition.

However, the cost price of these LED modules is still much higher today than that of conventional halogen modules, so that the use of lighting and signaling units made entirely of LED modules is currently reserved for high-end versions. of the different vehicle models.

The other versions of the same vehicle model must therefore also be fitted with lighting and signaling blocks, at least part of the functions of which are still ensured by conventional halogen bulbs.

For technical reasons, the arrangement of the lighting and / or signaling functions cannot be exactly the same for an entirely LED optical unit as for an optical unit fitted with conventional halogen bulbs, so that two distinct references of cover glass should be used.

Car manufacturers are therefore forced to develop two different injection molds to ensure the manufacture of these two glass references, which leads to a significant increase in investment (each mold having a cost of several hundred thousand euros).

Statement of the invention

The present invention aims to propose to improve the situation.

To this end, it proposes a method of manufacturing by molding a lens for a lighting or signaling unit for a vehicle, characterized in that it successively comprises the following steps:

- Installation of at least one interchangeable insert in at least one corresponding housing formed on the punch of a movable part of a mold;

- displacement of said movable part so that the latter closes on a first fixed part of said mold in which is formed a first die;

- Injection of a first translucent thermoplastic polymer into a wetting cavity delimited by said punch and said first matrix so as to constitute at least a first portion of said ice; and

- Removal of said movable part away from said first fixed part of the mold.

The method according to the invention thus makes it possible to obtain, by modifying the insert (s) placed in the punch of the movable part of the mold, glasses of identical shapes and dimensions but having, on at least one predetermined surface area, distinct reliefs adapted to different arrangements of light modules behind these windows.

Several references of glass for lighting or signaling units fitted to different versions of the same vehicle model can thus be manufactured from the same injection mold, which considerably reduces investment costs.

According to preferred characteristics of the process, taken alone or in combination:

each at least said interchangeable insert has either a smooth surface or a raised surface corresponding to the negative of a zone of diffusion of said glass provided with a plurality of optical elements capable of ensuring vertical and / or horizontal spreading of the light rays;

- Said first thermoplastic polymer consists of polymethyl methacrylate or polycarbonate;

said method comprises, after said removal of said movable part away from said first fixed part of the mold, the following steps:

• displacement of said movable part so that the latter closes on a second fixed part of said mold in which a second die is formed;

• injection of a second translucent thermoplastic polymer into a second mold cavity delimited by said punch, said first portion of the ice and said second matrix so as to constitute at least a second portion of the ice; and removing said movable part away from said second fixed part of the mold;

- Said second portion of the ice surrounds said first portion of the ice;

- Said second thermoplastic polymer has a different shade from that of said first thermoplastic polymer;

said method comprises, after said removal of said movable part away from said second fixed part of the mold, the following steps:

• displacement of said movable part so that the latter closes on a third fixed part of said mold in which is formed a third die;

• injection of a third thermoplastic polymer into a third molding cavity delimited by said punch, said second portion of the ice and said third matrix so as to constitute at least a third portion of the ice; and • removal of said movable part away from said third fixed part of the mold;

- Said third thermoplastic polymer is opaque; and or

- Said third portion of the ice is overmolded on said second portion.

The invention also relates in a second aspect to a pair of windows for optical lighting or vehicle signaling units comprising a first window and a second window of identical shapes and dimensions but having different reliefs on at least one predetermined surface area, characterized in that said first and second ice creams are obtained by such a process from the same mold but using different inserts.

Brief description of the drawings

The description of the invention will now be continued with the detailed description of an exemplary embodiment, given below by way of illustration but not limitation, with reference to the appended drawings, in which:

[Fig 1] shows a perspective view of an optical signaling unit glass;

[Fig 2] is a perspective view of an optical signaling unit glass having a profile and dimensions identical to the glass of Figure 1 but having on certain predetermined surface areas reliefs different from the latter;

[Fig 3] shows the flowchart of the molding manufacturing process according to the invention making it possible to produce the two windows of Figures 1 and 2;

[Fig 4] is a top view of the movable part of the plastic injection mold used in this process;

[Fig 5] shows a schematic sectional view of the first step of injecting the process;

[Fig 6] shows a schematic sectional view of the second step of injecting the process; and [Fig 7] shows a schematic sectional view of the third step of injecting the process.

detailed description

FIG. 1 represents an translucent outer glass cover 10 of an optical signaling unit, not shown, intended to be mounted on the body structure at the rear of a motor vehicle, and incorporating two halogen type light devices capable of perform three different photometric functions (position light, stop light, and direction indicator light).

The crystal 10 comprises a first translucent portion of crystal shade 11 made of polymethyl methacrylate (PMMA) behind which is intended to be positioned a first halogen type light device ensuring the direction indicator light function.

The inner face of this first crystal portion 11 comprises in its lower part a rectangular diffusion zone 11A extending over most of its length and being provided with a plurality of optical elements such as prisms, striations or else spherical or toric lenses ("balls") arranged on the internal face of the glass and capable of ensuring a vertical and / or horizontal spreading of the light rays emanating from this first device in order to obtain good lighting comfort and to satisfy to the photometry regulations imposing minimum horizontal geometric visibility angles for the direction indicator light function (45 ° internal side and 80 ° external side for horizontal angles; 15 ° above and below the horizontal for vertical angles).

The glass 10 also has a second translucent portion tinted red 12, surrounding the first portion 11, and also being made of polymethyl methacrylate (PMMA).

This second portion 12 comprises an upper strip 12A surmounting the first crystal-colored portion 11 and behind which is intended to be positioned a second halogen type light device ensuring the position light and stop light functions.

The internal face of this upper strip 12A comprises a rectangular diffusion zone 12B extending over most of its length and being provided with a plurality of elements arranged on the internal face of the glass and capable of ensuring vertical spreading and / or horizontal rays of light from this second device in order to obtain good lighting comfort and to meet the regulations in terms of photometry imposing minimum angles of horizontal geometric visibility for the position light function (these angles being identical to those for the direction indicator light function).

The glass 10 finally comprises a third opaque portion 13, also made of polymethyl methacrylate (PMMA), overmolded on a part of the peripheral zone of the second portion 12, and ensuring only a styling function.

FIG. 2 represents a translucent outer cover glass 20 of an optical signaling unit, not shown, intended to be mounted on the body structure at the rear of a motor vehicle, and incorporating three LED type light devices suitable for perform three different photometric functions (position light, stop light, and direction indicator light).

The crystal 20 comprises a first translucent portion of crystal color 21 made of polymethyl methacrylate (PMMA) and having a shape and dimensions identical to those of the first crystal portion 11 of the crystal 10.

This first portion 21 includes an upper part 21A behind which is intended to be positioned a first LED type light device ensuring the direction indicator light function, as well as a lower part 21B of larger dimension and behind which is intended to be positioned a second LED type light device ensuring the brake light function.

The inner face of the upper part 21A comprises, near its internal edge, a rectangular diffusion zone 21C being provided with a plurality of optical elements arranged on the internal face of the crystal and capable of ensuring vertical spreading and / or horizontal rays from this first light device in order to obtain good lighting comfort and comply with photometry regulations.

The inner face of the lower part 21B comprises a rectangular diffusion zone 21D identical to the diffusion zone 11A of the ice 10 and arranged in the same location as this zone 11A.

The ice 20 also has a second translucent portion of red color 22 surrounding the first portion 21, also made of polymethyl methacrylate (PMMA), and having a shape and dimensions identical to those of the second portion of red color 12 of the ice 10.

This second portion 22 comprises an upper strip 22A surmounting the first crystal-colored portion 21 and behind which is intended to be positioned a third second LED type light device ensuring the position light function.

Unlike the strip 12A of the first lens, this strip 22A has no diffusion zone such as 12B (compliance with the regulatory visibility angles being obtained by the presence of another adjacent optical signaling unit on the vehicle).

The crystal 20 finally comprises a third opaque style portion 23, also made of polymethyl methacrylate (PMMA), covering the major portion of the internal face of the peripheral zone of the second portion 12, and being perfectly identical the third opaque portion 13 ice 10.

FIG. 3 represents the flow chart of the molding manufacturing method according to the invention making it possible to produce the two windows 10 and 20.

Figure 4 a top view of the movable part 40 of the plastic injection mold used in this process.

This movable part 40 comprises a punch 41 intended to cooperate successively with three dies 51, 61, 62 formed respectively on three different fixed parts 50, 60, 70 of the mold, and shown in FIGS. 5, 6 and 7.

The punch 41 comprises two housings 41A, 41B formed respectively at the location of the diffusion zone 21C of the ice 20 and that of the diffusion zone 12B of the ice 10.

The housing 41A is designed to alternately receive two interchangeable inserts Ii, Ir respectively presenting a smooth surface and a raised surface corresponding to the negative of the diffusion zone 21C of the ice 20.

The housing 41B is in turn provided for alternately receiving two interchangeable inserts h, h 'having respectively a smooth surface and a raised surface corresponding to the negative of the diffusion zone 12B of the ice 10.

The first step of the method consists in installing the inserts corresponding to the desired ice pattern in the housings 41A, 41B formed in the punch 41 (step 100).

To manufacture the glass 10, the inserts Ii and I ₂ 'will thus be arranged; while to make the ice 20, the inserts Ir and I ₂ will thus be arranged.

The movable part 40 of the mold is then moved in translation until it closes on the first fixed part 50 so as to form with it a first molding cavity Cmi delimited by the punch 41 and the first die 51 (step 200) .

FIG. 5 illustrates the third step 300 of this process during which a first thermoplastic polymer (in this case polymethyl methacrylate of crystal hue) is injected hot and under pressure via an injection press not shown in this first cavity molding Cmi, so as to constitute the first portion 11 or 21 of the ice 10 or 20 (depending on the insert h or Ir inserted in the housing 41A of the punch 41).

Such an injection molding machine conventionally comprises a hopper for collecting granules of thermoplastic resin and a motorized and heated endless screw through which the granules coming from the hopper are conveyed in the form of a viscous injectable fluid. towards an injection head fluidly connected to at least one nozzle Bi formed in the first die 51 and opening into the molding cavity Cmi.

After this first injection step and a cooling time, the movable part 40 of the mold is removed away from the first fixed part 50, carrying with it the first portion 11 or 21 thus produced (step 400).

The movable part 40 of the mold is then moved in rotation so as to come to be positioned opposite the second fixed part 60 of the mold, then it is moved in translation until it closes on this fixed part 60 so as to form with it a second mold cavity C _M 2 delimited by the punch 41, the first portion 11 or 21 and the second die 61 (step 500).

FIG. 6 illustrates the next step 600 of this process during which a second thermoplastic polymer (in this case translucent polymethyl methacrylate tinted in red) is injected hot and under pressure into this second molding cavity C _M 2 so as to constitute the second portion 12 or 22 of the ice 10 or 20 (depending on the insert hou I ₂ - inserted in the housing 41B of the punch 41).

This second injection step is carried out via a second injection press, the injection head of which is fluidly connected to at least one nozzle B ₂ formed in the second matrix 61 and opening into the grinding cavity C _M 2.

After this second injection step and a cooling time, the movable part 40 of the mold is removed away from the second fixed part 60, carrying with it the first portion 11 or 21 and the second portion 12 or 22 thus produced. (step 700).

The movable part 40 of the mold is then moved in rotation so as to come to be positioned opposite the third fixed part 70 of the mold, then it is moved in translation until it closes on this fixed part 70 so as to form with it a third overmolding cavity C _M 3 delimited by the punch 41, the first portion 11 or 21, the second portion 12 or 22 and the third die 71 (step 800).

FIG. 7 illustrates the following step 900 of this process during which a third thermoplastic polymer (in this case, opaque black polymethyl methacrylate) is injected hot and under pressure into this third overmolding cavity C _M 3 of so as to constitute the third portion 13 or 23 of the ice 10 or 20 (these portions being identical on the two versions of ice).

This third injection step is carried out via a third injection press, the injection head of which is fluidly connected to at least one nozzle B ₃ formed in the third die 71 and opening into the molding cavity C _M 3.

After this third injection step and a cooling time, the movable part 40 of the mold is removed away from the third fixed part 70 by carrying with it the ice 10 or 20 thus produced (step 1000).

According to variant embodiments not shown, the number of housings formed in the punch intended to receive interchangeable inserts and / or the number of interchangeable inserts intended to be received in the same housing are different.

According to other variant embodiments not shown, the number of successive injection steps (and therefore of fixed parts of the mold) is also different.

In particular, the second and / or third injection step may be absent, so that the ice produced is only two-color or one-color.

According to yet other alternative embodiments not shown, the thermoplastic polymers injected are different. Polymethyl methacrylate (PMMA) can for example be replaced by polycarbonate (PC).

In general, it is recalled that the present invention is not limited to the embodiments described and shown, but encompasses any variant within the reach of the skilled person.

In particular, it should be noted that the method according to the invention is not limited to the manufacture of rear signaling optical units but that it can also be implemented for the manufacture of optical signaling and / or lighting units intended to be installed at the front of the vehicle.

Claims (10)

1. Method for manufacturing, by wetting, a window (10, 20) of a lighting or signaling unit for a vehicle, characterized in that it successively comprises the following steps: - Installation of at least one interchangeable insert (h, h-, I ₂ , Ir) in at least one corresponding housing (41A, 41B) formed on the punch (41) of a movable part (40) d 'a mold (100); - displacement of said movable part (40) so that the latter closes on a first fixed part (50) of said mold in which is formed a first die (51) (200); injection of a first translucent thermoplastic polymer into a molding cavity (Cmi) delimited by said punch (41) and said first matrix (51) so as to constitute at least a first portion (11, 21) of said ice (300 ); and - removal of said movable part (40) away from said first fixed part (50) of the mold (400). 2. Method according to claim 1, characterized in that each at least said interchangeable insert (Ii, Ir, I ₂ , Ir) has either a smooth surface or a raised surface corresponding to the negative of a diffusion zone (11A , 21C) of said glass provided with a plurality of optical elements capable of ensuring a vertical and / or horizontal spreading of the light rays. 3. Method according to one of claims 1 or 2, characterized in that said first thermoplastic polymer consists of polymethyl methacrylate or polycarbonate. 4. Method according to one of claims 1 to 2, characterized in that it comprises, after said withdrawal of said movable part (40) away from said first fixed part (50) of the mold (400), the following steps: - displacement of said movable part (40) so that the latter closes on a second fixed part (60) of said mold in which a second die (61) (500) is formed; - injection of a second translucent thermoplastic polymer into a second mold cavity (Cm2) delimited by said punch (41), said first portion of the ice (11, 21) and said second matrix (60) so as to constitute at least a second portion of the ice (12, 22) (600); and - Removing said movable part (40) away from said second fixed part (60) of the mold (700). 5. Method according to claim 4, characterized in that said second portion of ice (12, 22) iadite said first portion of ice (11, 21). 6. Method according to one of claims 4 or 5, characterized in that said second thermoplastic polymer has a different shade from that of said first thermopiastic polymer. 7. Method according to one of claims 4 to 6, characterized in that it comprises, after said withdrawal of said movable part (40) away from said second fixed part (60) of the mold (700), the following steps: - displacement of said movable part (40) so that the latter closes on a third fixed part (70) of said mold in which a third die (71) (800) is formed; injection of a third thermoplastic polymer into a third wetting cavity (Cm3) delimited by said punch (41), said second portion of the ice (12, 22) and said third matrix (71) so as to constitute at least one third portion of the giace (13, 23) (900); and - Removal of said movable part (40) away from said third fixed part (70) of the mold (1000). 8. Method according to claim 7, characterized in that said third thermoplastic polymer is opaque. 9. Method according to one of claims 7 or 8, characterized in that said third portion of the giace (13, 23) is molded onto said second portion (12, 22). 10. Pair of windows for vehicle lighting or signaling optical units comprising a first window (10) and a second window (20) of identical shapes and dimensions but having on at least one predetermined surface area (12B, 21C) landforms 5 different, characterized in that said first and second glasses (10, 20) are obtained by a process in accordance with one of claims 1 to 9 from the same mold but using different inserts (h, Ir, I ₂ , h ') ·