EP2839165B1 - Motor vehicle fan of reduced axial size - Google Patents

Description

The field of the present invention is that of the automobile, and more particularly that of air circulation for cooling vehicle equipment, and in particular its engine.

Thermal engine vehicles need to evacuate the calories generated by their operation and they are therefore equipped with heat exchangers, in particular cooling radiators, which are placed at the front of the vehicle and which are crossed by outside air. To force the circulation of this air through the exchanger (s), a fan is placed upstream or downstream thereof, upstream or downstream being assessed in this document with reference to the flow direction of the air. The propeller which serves to force the air circulation is characterized by a high flow rate and low pressure and has a very axially oriented flow.

The fan generally comprises a nozzle or base, of parallelepiped shape, which is crossed at its center by a hollow cylindrical cavity in which the propeller is positioned. This base ensures the attachment of the fan to a support, in particular the cooling radiator or the frame, as well as the support of the electric motor for actuating the propeller and the maintenance of the axis around which the latter rotates. In addition, aerodynamically, it forms a frontal obstacle for the air flow, which forces it to move towards the propeller.

In the fans of the prior art, the propeller is flush with and / or is driven axially, downstream, with respect to the frontal plane of the support, as can be seen in the figures. figures 1 to 3 . The propeller is configured so that the air which circulates on the upstream face of the front wall of this support crosses a difference in level by flowing into the propeller. It then follows a plunging path towards the propeller, which is favorable to its mixing with the main air flow which, for its part, arrives in a purely axial direction.

This configuration has, on the other hand, the drawback of too great an axial extension for the fan, the side walls of the base extending upstream from this frontal plane, which is therefore located at a position axially more upstream than the plane. upstream of the propeller. For reasons of overall size of the fan and taking into account the severe constraints imposed on the front panel equipment of motor vehicles on this point, it is important to optimize the axial size of the fan, without however degrading its aerodynamic performance.

The object of the present invention is to remedy these drawbacks by proposing an improved fan with minimum axial size.

To this end, the invention relates to a fan for a motor vehicle according to claim 1 comprising a propeller formed from several blades and a propeller support base, said propeller being rotated about an axis of rotation, said propeller base comprising an upstream front wall facing the ventilation air flow and extending outwardly in a radial plane with reference to said axis, and an outer wall extending axially from said front wall.

According to the invention, said front wall has a protuberance bordering the helix, said protuberance extending axially upstream with respect to the plane of said front wall, and the upstream end of which is located further upstream than the end. upstream of the blades of said propeller, the blades are connected externally to a ferrule, said front wall is positioned axially in the same plane as said upstream end of the blades and / or of the ferrule, and said protuberance has the shape of a rib of revolution entirely located radially outside the outer end of the blades or of the shell and attached to the axial wall of said cylindrical cavity.

The presence of this protuberance at the internal level of the front wall makes it possible, while limiting the aerodynamic losses, to move back downstream the outer part of the wall and thus to move back its outer wall which directly participates in the definition of the bulk. axial fan.

• ladite excroissance est circulaire, entourant l'hélice,
• ladite paroi frontale est positionnée axialement en aval de ladite extrémité amont des pales et/ou de la virole,
• l'hélice est positionnée à l'intérieur d'une cavité cylindrique creuse, de même axe, formée par une paroi axiale rattachée au socle de sorte que ladite cavité cylindrique soit située face, notamment, à une extrémité extérieure des pales,
• ladite nervure a, en coupe radiale, une forme dont la pente est continûment variable entre ladite paroi frontale amont et ladite paroi axiale,
• ladite nervure se rattache à ladite paroi axiale selon une direction axiale ou est orientée selon un plan radial au niveau de sa jonction avec ladite paroi axiale,
• ladite excroissance a la forme d'une nervure de révolution qui s'étend jusqu'à une extrémité radiale intérieure positionnée radialement à l'intérieur de l'extrémité extérieure des pales ou de la virole, de sorte à se rattacher, notamment, à la paroi axiale de la cavité cylindrique,
• la nervure de révolution forme un conduit de guidage du flux circulant entre la virole et la paroi axiale,
• ladite nervure de révolution a, en coupe radiale, une forme dont la pente est continûment variable entre la partie radiale de ladite paroi frontale amont et son extrémité radiale intérieure,
• ladite nervure se rattache à ladite paroi axiale selon une direction axiale à partir de ladite extrémité radiale intérieure,
• ladite nervure est orientée selon un plan radial au niveau de son extrémité radiale intérieure.

According to different embodiments which can be taken together or separately:

• said protuberance is circular, surrounding the helix,
• said front wall is positioned axially downstream of said upstream end of the blades and / or of the ferrule,
• the propeller is positioned inside a hollow cylindrical cavity, of the same axis, formed by an axial wall attached to the base so that said cylindrical cavity is located opposite, in particular, an outer end of the blades,
• said rib has, in radial section, a shape whose slope is continuously variable between said upstream front wall and said axial wall,
• said rib is attached to said axial wall in an axial direction or is oriented along a radial plane at its junction with said axial wall,
• said protuberance has the form of a rib of revolution which extends to an inner radial end positioned radially inside the outer end blades or the ferrule, so as to be attached, in particular, to the axial wall of the cylindrical cavity,
• the rib of revolution forms a guide duct for the flow circulating between the ferrule and the axial wall,
• said rib of revolution has, in radial section, a shape the slope of which is continuously variable between the radial part of said upstream front wall and its inner radial end,
• said rib is attached to said axial wall in an axial direction from said inner radial end,
• said rib is oriented in a radial plane at its inner radial end.

As indicated above, said front wall is advantageously positioned axially downstream of said upstream end of the blades and / or of the ferrule. This very remote position of the front wall makes it possible to reduce the axial size of the fan. The invention also relates to a motor vehicle cooling module comprising a fan as described above. A cooling module of a motor vehicle engine block is an assembly comprising in particular a fan and a heat exchanger such as a cooling radiator.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will emerge more clearly during the detailed explanatory description which follows, of several embodiments of the invention given by way of purely illustrative and non-limiting examples, with reference to the accompanying schematic drawings.

• la figure 1 est une vue de face, depuis l'amont, d'un ventilateur pour véhicule automobile, selon l'art antérieur;
• la figure 2 est une vue schématique en coupe radiale du ventilateur de la figure 1 ;
• la figure 3 est une vue schématique simplifiée de la figure 2 ;
• la figure 4 est une vue en perspective d'un ventilateur pour véhicule automobile, selon un exemple non revendiqué
• la figure 5 est une vue schématique simplifiée, en coupe radiale, du ventilateur de la figure 4 ;
• la figure 6 est une vue schématique simplifiée, en coupe radiale, du ventilateur de la figure 4 ;
• la figure 7 est une vue schématique simplifiée, en coupe radiale, du ventilateur de la figure 4, dans un mode de réalisation,
• la figure 8 est une vue schématique simplifiée, en coupe radiale, du ventilateur de la figure 4, dans une variante du mode de réalisation, et
• la figure 9 est une vue schématique simplifiée, en coupe radiale, du ventilateur de la figure 4, dans une variante supplémentaire du mode de réalisation.

On these drawings:

• the figure 1 is a front view, from upstream, of a fan for a motor vehicle, according to the prior art;
• the figure 2 is a schematic radial sectional view of the fan of the figure 1 ;
• the figure 3 is a simplified schematic view of the figure 2 ;
• the figure 4 is a perspective view of a fan for a motor vehicle, according to an example not claimed
• the figure 5 is a simplified schematic view, in radial section, of the fan of the figure 4 ;
• the figure 6 is a simplified schematic view, in radial section, of the fan of the figure 4 ;
• the figure 7 is a simplified schematic view, in radial section, of the fan of the figure 4 , in one embodiment,
• the figure 8 is a simplified schematic view, in radial section, of the fan of the figure 4 , in a variant of the embodiment, and
• the figure 9 is a simplified schematic view, in radial section, of the fan of the figure 4 , in a further variant of the embodiment.

With reference to the figure 1 , we see, from the front, a fan 1 for which a propeller is inserted in a hollow cylindrical cavity placed in the center of a base 2 of parallelepiped shape. The base has a substantially planar front wall 22 facing the flow of ventilation air and an outer wall 23 which surrounds the front wall 22 and which forms a duct for conveying air into the fan 1. The propeller of the fan comprises a series of blades 3 which are attached at their central end to a hub 4 and, here, at their peripheral end to a circular ferrule 5. The fan 1 rotates around a central axis 6 driven by a means of 'actuation, in particular an electric motor 7 (visible on the figure 2 ).

We see on the figure 2 stator vanes 8 positioned downstream of the blades 3, the object of which is to serve as a support for the electric motor 7 and to guide the air flow at the outlet of the fan.

As with all fans, there is an air recirculation current, which goes from downstream of the fan to upstream bypassing the ends of the blades 3, which should be minimized. For this it has already been proposed a ring 9 in the form of a quarter torus, visible on the figure 2 , which is placed between the downstream side of the blades 2 and the upstream side of the stator vanes 8 and which extends radially from the outer wall towards the inside of the fan. The purpose of this quarter-torus 9, by using the Coanda effect, is to preferentially deflect the air flow downstream of the blades 2 towards the stator 8 and thus prevent it from orienting at the periphery, in the direction of walls of base 2 and that it feeds the recirculation circuit. The Coanda effect consists of an attraction of a jet of fluid by a wall when it circulates near it. It is generally used to produce a deviation in the orientation of the jet, by choosing a curved wall as the wall, which is the case here with the quarter-torus shape of the ring 9.

To further reduce this recirculation flow, the shell 5, in radial section, has been given an L-shape, the axial branch of which forms the support for the ends of the blades 3 and the radial branch of which covers the cylindrical part, radially. innermost 21, of the support 2. This internal radial part 21 forms the cylindrical cavity in which is positioned the propeller. To accommodate the radial branch of the shell 5, the support 2 has consequently been modified with the introduction of a shoulder formed by an L-shaped cutout between its internal radial part 21 and its front wall 22. This L-shaped cutout has a first radial wall 26, which is parallel to the radial branch of the shell 5, and an axial wall 25 which faces this end of the radial branch of the shell and which is connected to the front wall 22 of the base. Finally, as indicated above, to the outer radial end of the front wall 22 is attached the outer wall 23 which extends axially and which forms a duct for the delivery of air into the fan. Axially, this outer wall 23 extends from the front wall 22, over a length which is determined by considerations of the mechanical strength of the assembly and which cannot be reduced without adverse consequences.

The resulting axial deviation, between the upstream face of the shell 5 and the upstream end of the outer wall 23, increases the overall axial size d of the fan, as can be seen in the figure. figure 3 . This is what the invention sets out to correct.

The figure 4 shows a fan. The front wall 22 of the base 2 is not flat, as is the case in the prior art, but it has, at its internal radial end, a protuberance in the form of a lip 24, which extends towards the upstream from the front wall 22 and which connects, in an axial direction, to the axial wall 25 of the L-shaped cutout of the support 2. As a result, the front wall 22 of the support 2 is in a less advanced position towards upstream with respect to the upstream face of the ferrule 5, than in the prior art. And, consequently, the outer wall 23, which extends from this front wall and which may have the same axial extension as in the prior art, is itself also less advanced axially with respect to the upstream face of the hub 4 or of the ferrule 5. The axial size d of the fan is thus reduced.

The figure 5 shows, in a simplified manner, a first variant of the fan. According to this variant, the lip 24 bends, going from the periphery towards the inside, with a shape whose slope evolves continuously, without breaking, before joining the axial wall 25 in an axial direction while being tangent to it. this.

On the figure 6 , which shows a second variant, the axial position of the front wall 22 is unchanged with respect to the first variant, so as to keep the gain obtained on the overall axial size d. But unlike the first variant, the lip 24 has a break in its slope with a right angle at its connection with the axial wall 25 of the L-shaped cutout. The slope of the The lip thus evolves continuously until it reaches a radial orientation, precisely where the lip connects to the axial wall 25.

In the first variant, the air which runs along the front part undergoes a Coanda effect associated with the curved shape of the lip 24 and is directed more axially when it arrives at the end of the blades 3, which facilitates its mixing with the flow of air. main air flowing through them. The second variant promotes, for its part, the return of the circulating air at the end of the blades to the main flow, by injecting the flow circulating along the front wall 22 in a radial direction, above the recirculation circuit. .

The figures 7 and 8 show, for their part, two variants of an embodiment of the invention. In this mode, the lip 24 is extended, at its most upstream part, towards the interior of the fan, so that it overflows and covers the outer radial end of the ferrule 5. The figure 7 shows the first variant with, as before, a rounded top which bends, coming inward, in the direction of the axial direction. Beyond this apex, the lip 24 ends in a cusp, from which it returns outwardly heading downstream, to join the axial wall 25 of the L-shaped cutout in an axial orientation. This rounded shape enables the air flow which circulates along the front wall 22 to benefit from the Coanda effect and straightens it in a more axial direction.

The figure 8 shows the second variant of the mode, with, as above, a radial orientation at the top of the lip. Likewise, the latter has a cusp and returns to the outside while moving downstream, to join the axial wall 25 of the L-shaped cutout in an axial orientation. This second variant also promotes the return, towards the main flow, of the circulating air at the end of the blades, by injecting the flow which circulates along the front wall 22 in a radial direction, above the circuit. recirculation.

In the figures 5 to 8 above, the front wall 22 is positioned axially in the same plane as said upstream end of the blades 3 and / or of the ferrule 5.

As shown in figure 9 , it can also be located downstream. It is shown here with an outgrowth identical to that of the figure 5 but it could of course be an outgrowth of different shapes such as those illustrated in figures 6 to 8 .

The principle of the invention therefore consists, compared with the prior art, in reducing the axial bulk of the fan by shifting the front wall 22 downstream, and more particularly its upstream face, forming the front face of the parallelepipedic support 2. , all while keeping the same length for the outer wall 23. To compensate for this offset of the front wall 22 and regain the improved aerodynamic operation which is associated with an injection of the air circulating on the front wall 22 above the peripheral shell 5 , a lip 24 is introduced at the inner radial end of this front wall 22. This lip has the shape of a rib, for example rounded circular, which extends axially upstream above the front wall 22 and which here is connected in an axial orientation, to the axial wall 25 facing the shell 5. Thus the air circulating on the front wall 22 is raised upstream to be injected into the main air flow without generate vortex and therefore create as little disturbance as possible in this main flow.

In the embodiment the lip 24 extends above the outer radial end of the shell 5, thus forming a guide duct for the recirculation flow which circulates between the shell 5 and the axial wall 25 of the support 2. It also acts as a separator between the recirculation flows and the flow circulating on the front wall 22 before it is injected into the main flow which passes through the blades 3.

In a variant, not shown, of the embodiment, it is possible to install guides below the part of the lip 24 which extends between the kink point and the axial wall 25, to straighten the flow of recirculation and prevent it from acquiring a tangential speed by a drive effect of the shell. These guides are plates oriented essentially radially, which extend from the inner circle to the lip 24 and which have, on the side opposite to this circle, an edge either diagonal or curved opposite the end of the ferrule 5. By reducing the tangential component of the recirculation flow, it is thus possible to better manage its mixing with the main flow.

Claims (12)

1. Fan for a motor vehicle, comprising an impeller formed by multiple blades (3) and a base (2) supporting the impeller, said impeller being rotated about an axis of rotation (6), said base comprising an upstream front wall (22) facing the ventilation air flow and extending externally in a radial plane with reference to said axis, and an outer wall (23) extending axially from said front wall,
   said front wall (22) having a protrusion (24) bordering the impeller, said protrusion extending axially upstream with respect to the plane of said front wall, and the upstream end of which is situated further upstream than the upstream end of the blades (3) of said impeller, the blades (3) being connected externally to a shroud (5), and said protrusion having the form of an axisymmetric rib (24) which extends as far as an inner radial end positioned radially inside the outer end of the blades (3) or of the shroud (5), characterized in that said front wall is positioned axially in the same plane as said upstream end of the blades and/or of the shroud.
2. Fan according to Claim 1 in which said protrusion is circular, surrounding the impeller.
3. Fan according to either of Claims 1 and 2, in which said front wall (22) is positioned axially downstream of said upstream end of the blades (3) and/or of the shroud (5).
4. Fan according to Claim 3 in which the impeller is positioned inside a hollow cylindrical cavity having the same axis and formed by an axial wall (25) attached to the base (2).
5. Fan according to Claim 4 in which said protrusion has the form of an axisymmetric rib (24) entirely situated radially outside an outer end of the blades (3) or of the shroud (5) and attached to the axial wall (25) of said cylindrical cavity.
6. Fan according to Claim 5 in which said rib (24) has, in radial section, a shape whose slope is continuously variable between said upstream front wall (22) and said axial wall (25) .
7. Fan according to Claim 5 or 6 in which said rib (24) is attached to said axial wall in an axial direction or is oriented in a radial plane at its junction with said axial wall.
8. Fan according to Claim 4 in which the axisymmetric rib (24) forms a guide duct for the flow circulating between the shroud (5) and the axial wall (25) .
9. Fan according to Claim 4 to 8 in which said axisymmetric rib (24) has, in radial section, a shape whose slope is continuously variable between the radial part of said upstream front wall (22) and its inner radial end.
10. Fan according to any one of Claims 1, 8 and 9 in which said rib is attached to said axial wall (25) in an axial direction.
11. Fan according to any one of Claims 1, 8 and 9 in which said rib is oriented in a radial plane at its inner radial end.
12. Motor vehicle cooling module comprising a fan according to one of the preceding claims.

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