EP2397021A1

EP2397021A1 - Protection cover for one or more parts having a suction effect air-channelling element, and related housing

Info

Publication number: EP2397021A1
Application number: EP10708313A
Authority: EP
Inventors: Thomas Gysels; Tony Houdinet
Original assignee: Peugeot Citroen Automobiles SA
Current assignee: PSA Automobiles SA
Priority date: 2009-02-13
Filing date: 2010-02-09
Publication date: 2011-12-21
Also published as: FR2942367B1; FR2942367A1; CN102450114A; WO2010092294A1; BRPI1005954A2

Abstract

The invention relates to a cover (CP) for protecting at least one part (c1) capable of radiating heat, and comprising a main wall (PP) provided with ventilation means (MAi) and adapted, once installed in a system, to be mounted opposite said part (C1) in a vertical or inclined direction. Said ventilation means (MAi) includes at least one air-channelling means protruding above the general level of the outer surface (FE) of the main wall (PP) and having a so-called lower end (E1) provided with an air inlet (EA) communicating with an inner area (ZI) located behind the inner surface (FI) of the main wall (PP) opposite the outer surface (FE), and a so-called upper end (E2) provided with an air outlet (SA) communicating with the inner area (ZI) and adapted, once the cover is installed, to be located at a higher level than that of the air inlet (EA) so as to induce an air suction effect for promoting the dissipation of the heat radiated by thermal convection.

Description

PIECE PROTECTIVE COVER (S) WITH SUCTION EFFECT AIR PIPING ELEMENT (S) AND HOUSING THEREFOR

The invention relates to protective covers which are responsible for protecting at least one radiating part of the heat, such as a printed circuit board or PCB (for "Printed Circuit Board").

As known to those skilled in the art, some parts that radiate heat (for example because they include at least one electronic component) are relatively fragile and must therefore be protected by a protective cover or by a housing comprising, for example, a base or a support piece and a protective cover secured to one another (possibly by clipping).

The radiating part of the heat, the latter must be evacuated to avoid overheating. To do this, one can for example use a very small fan charged with sucking outside air to cool the indoor air heated by the radiation or to suck up the indoor air heated by the radiation for the expel to the outside. This solution provides efficient cooling, but it is expensive, cumbersome, noisy and consumes electrical energy.

Another solution is to define aeration means on a main wall of the protective cover, intended, once installed, to be placed facing the room. These aeration means are generally in the form of simple openings (or aerators) defined in the main wall. These openings must remain small so that the room can be effectively protected, they leave little external air to penetrate, so that the cooling is not very effective. In fact, most of the surrounding outside air only licks the outer face of the hood's main wall in the vicinity of the openings, and cools the indoor air only when it reaches the outside. outside.

The invention therefore aims to improve the situation by means of a passive solution (that is to say which does not consume electrical energy).

It proposes for this purpose a protective cover, intended to protect at least one part (for example a printed circuit (or PCB)), which, in operation, can radiate heat, and having a main wall provided with aeration means and intended, once installed in a system, to be placed facing the room and in a vertical direction or an inclined direction.

This protective cover is characterized in that its aeration means comprise at least one air channeling element protruding above the general level of an outer face of its main wall and having a so-called lower end which is provided with an air inlet communicating with an internal zone located behind an inner face of the main wall, opposite to the outer face, and an upper end which is provided with an air outlet communicating with the internal zone and intended, once the hood is installed, to be located at a level higher than that of the air inlet to induce a suction effect of clean air to promote the evacuation of heat radiated heat convection.

The protective cover according to the invention may comprise other features that can be taken separately or in combination, and in particular:

- The aeration means may comprise at least two air channeling elements, which may be optionally substantially parallel to each other;

the air inlet may have an air intake surface greater than the air expulsion surface of the air outlet;

> the air intake area may be at least 40% greater than the air expulsion surface;

each air duct element can be arranged in the form of a cylindrical duct; each air duct element may have a shape suitable for inducing a Venturi type effect;

each air duct element may comprise a section transverse of substantially rectangular shape;

- The air inlet and / or the air outlet can be equipped (s) with a clean grid to limit the entry of foreign bodies.

The invention also provides a housing comprising a protective cover of the type shown above.

Other features and advantages of the invention will appear on examining the detailed description below, and the attached drawings, in which:

FIG. 1 schematically illustrates, in a sectional view in a plane containing the vertical direction (DV), an exemplary embodiment of a housing comprising a protective cover according to the invention,

FIG. 2 schematically illustrates, in a front view of the side of the lower side wall, the casing of FIG. 1, and

- Figure 3 schematically illustrates, in a front view, a lower end of the air duct element provided with a gate at its air inlet.

The attached drawings may not only serve to complete the invention, but also contribute to its definition, if any.

The invention aims to provide a protective cover (CP) for protecting at least one piece (Cl) radiating heat.

In the following, it is considered, by way of non-limiting example, that the protective cover (CP) is part of a housing (B) intended to house and protect at least one piece (Cl) of printed circuit type ( or PCB). But, the invention is not limited to this type of room. It concerns indeed any type of radiating part of the heat and to be protected by at least one protective cover.

Furthermore, it is considered in the following, by way of non-limiting example, that the protective cover (and thus the housing (B)) is intended to be part of a vehicle, for example of the automotive type (such as example a car). But, the invention is not limited to this application.

Referring first to Figures 1 and 2 to show an embodiment of a protective cover CP according to the invention. In the nonlimiting example illustrated, the protective cover CP is secured to a base (or part support (s)) EM with which it constitutes a housing B. This connection can be done by any means known to the man of art, and in particular by clipping or screwing. The piece Cl (here a printed circuit comprising in particular electronic components CE) is fixed on the base EM. Note that in the absence of EM socket (and therefore of housing B), the piece Cl can be fixed to the protective cover CP.

The protective cover CP comprises for example a main wall PP, a so-called lower side wall PLI, a so-called upper side wall PLS, and two complementary side walls secured to each other.

The main wall PP is provided with ventilation means MAi and intended, once the protective cover CP has been installed in a system (here a car), to be placed opposite the room Cl (here a printed circuit) and in a vertical direction DV or an inclined direction.

In the nonlimiting exemplary embodiment illustrated in FIG. 1, the main wall PP is placed in a plane that contains the vertical direction DV. But, it could be placed in a plane inclined relative to this vertical direction DV. The angle of inclination must be strictly less than +/-

80 °, and preferably less than +/- 30 °.

The ventilation means MAi comprise at least one air channeling element which protrudes above the general level of an outer face FE of the main wall PP, opposite to an internal face F1 oriented towards the piece C1.

In the non-limiting embodiment illustrated in FIG. 2, the ventilation means MAi comprise three salient air channeling elements MA1 to MA3 (i = 1 to 3). However, the invention is not limited to this number (3) of air channeling elements MAi. It requires in fact that the main wall PP is provided with at least one air channeling element. Thus, the ventilation means MAi may comprise one or two salient air channeling elements MAi, or even more than three (for example four or five). Moreover, in the nonlimiting exemplary embodiment illustrated in FIG. 2, the air channeling elements MAi are substantially parallel to each other, and moreover substantially identical. But, this is not mandatory. They could indeed be different from each other and / or be oriented in slightly different ways. Thus, at least one of their dimensions along the three directions of space could vary.

Each air duct element MAi has two ends

E1 and E2 opposed to each other and respectively said lower and upper. It will be understood, as illustrated, that the lower end E1 is intended to be located at a level below that where is intended to be located the upper end E2.

The lower end E1 is provided with an air inlet EA which communicates with an internal zone Z1 which is located behind the inner face Fl of the main wall PP and which contains the piece C1. The upper end E2 is provided with an air outlet SA which also communicates with the internal zone Z1.

Note that it is preferable that the lower ends E1 and E2 upper communicate with each other, as illustrated. But, this is not mandatory. It could indeed be envisaged that there is a partition (solid or provided with an opening defining a narrowing) which separates them inside their air duct element MAi, so as to force the flow of air from from the outside to penetrate deeper inside the inner zone Z1 and / or to accelerate.

Due to the respective final positioning of the lower ends E1 and upper E2 (that is once the protective cap CP is installed), the air outlet SA of an air duct element MAi is located at a level which is higher than that of the EA air inlet of the same air duct element MAi. There is therefore a pressure difference between the air outlet SA and the air inlet EA which induces an air suction effect similar to that which exists in a chimney. Outside air

(fresh) that enters an air duct element MAi through its air intake EA (lower) is sucked upwards by the air outlet SA (upper), which promotes the evacuation of heat radiated by the piece Cl by thermal convection. It is recalled that the hot air spontaneously tends to rise.

In other words, the fresh outside air enters the internal zone Z1 with each air inlet EA, absorbs by thermal convection the calories carried by the internal air which has been heated by the radiation produced by the piece C1, and is expelled as heated air out of the protective cap CP, via each air outlet SA.

As illustrated without limitation in FIG. 2, in order to accelerate the extraction of the convective air flow (that is to say the air heated by the radiated calories), it is advantageous that the inlet EA air has an air intake surface greater than the air expelling surface of the air outlet SA. Note that in Figure 2 the air expulsion surface of the air outlet SA is shown in dotted lines because this figure is a front view of the side of the lower side wall PLI (and therefore on the side of the EA air inlet). It will be understood that this surface difference between the input EA and the output SA is intended to create a vacuum which induces an aspiration (and therefore an acceleration of the air flow).

For example, the air inlet area of the air inlet EA may be at least 40% greater than the air expelling surface of the air outlet SA. Preferably, it is chosen greater than at least 50%.

The EA air inlet and the SA air outlet are not necessarily placed substantially one above the other (i.e. substantially vertically aligned once installed) as shown. Indeed, we can consider that they are slightly offset in a substantially horizontal direction. Thus, it may be advantageous for the air outlet SA to be shifted forward with respect to the air inlet EA.

Furthermore, in the example illustrated in Figures 1 and 2, each air duct element MAi is arranged in the form of a cylindrical duct of rectangular cross section. But, this is not mandatory. Indeed, the transverse section may have other shapes than the rectangular shape (for example square or semi-circular or semi-elliptical), and an air channeling element MAi may not be cylindrical (its shape may indeed to be curvilinear, for example). Note that in the presence of a transverse section of substantially rectangular shape it is advantageous that the largest side of the rectangle has an extension much greater than the smaller side of this rectangle. For example, an extension ratio of between about 2 and about 5 may be envisioned.

In addition, each air duct element MAi may optionally have a shape suitable for inducing a Venturi type effect. For example, each air duct element MAi may have at least one narrowing located between its lower ends E1 and upper E2. Such a narrowing is intended to induce an acceleration of the air flow.

Finally, and as illustrated in FIG. 3, it is possible to equip the air intake EA and / or the air outlet SA with a gate G intended to limit the entry of foreign bodies (for example small objects or waste) within the inner zone Zl. Note that each grid G may be an insert or may be an integral part of an EA air inlet or an air outlet SA.

This grid can be in any form since it allows to intercept foreign bodies whose size is less than a chosen threshold. Thus, in the example shown, the grid G comprises a square grid, but it could comprise a rectangular grid or diamond, or include circular holes or elliptical.

The protective cover CP according to the invention may advantageously be made of plastic or synthetic material, for example by molding by means of a mold (the complexity of which may be limited when the air channeling elements have relatively simple shapes, for example of the type illustrated in Figures 1 to 3).

The invention is not limited to the embodiments of protective cover and housing described above, only by way of example, but it encompasses all variants that may be considered by those skilled in the art within the scope of the invention. claims below.

Claims

1. Protective cover (CP) for at least one room (Cl) capable of radiating heat, said cover (CP) comprising a main wall (PP) provided with aeration means (MAi) and intended, once installed in a system, to be placed opposite said part (Cl) and in a vertical direction or an inclined direction, characterized in that said aeration means (MAi) comprise at least one air channeling element projecting above the general level of an outer face (FE) of said main wall (PP) and having a so-called lower end (E1) provided with an air inlet (EA) communicating with an internal zone (Z1) located behind a face internal (Fl) of said main wall (PP), opposed to said outer face (FE), and an upper end (E2) provided with an air outlet (SA) communicating with said internal zone (Z1) and intended once said hood (CP) is installed, to be located at a higher level than that of said air inlet (EA) so as to induce an effect of clean air suction to promote the evacuation of heat radiated heat convection.

2. Cover according to claim 1, characterized in that said aeration means (MAi) comprise at least two air channeling elements.

3. Hood according to claim 2, characterized in that said air channeling elements (MAi) are substantially parallel to each other.

4. Cover according to one of claims 1 to 3, characterized in that said air inlet (EA) has an air intake surface greater than the air expulsion surface of said air outlet (HER).

Hood according to claim 4, characterized in that said air intake surface is at least 40% greater than said air expulsion surface.

6. Hood according to one of claims 1 to 5, characterized in that each air duct element (MAi) is arranged in the form of a cylindrical duct.

Cover according to one of Claims 1 to 6, characterized in that each air duct element (MAi) has a shape to induce a Venturi type effect.

8. Hood according to one of claims 1 to 7, characterized in that each air duct element (MAi) comprises a transverse section of substantially rectangular shape.

9. Hood according to one of claims 1 to 8, characterized in that said air inlet (EA) and / or said air outlet (SA) is / are equipped (s) with a grid (G) to limit the entry of foreign bodies.

10. Housing (B), characterized in that it comprises a protective cover (CP) according to one of claims 1 to 9.