WO2012084499A1

WO2012084499A1 - Fan impeller and associated cooling module

Info

Publication number: WO2012084499A1
Application number: PCT/EP2011/071940
Authority: WO
Inventors: Bruno Demory; Manuel Henner; Elias Tannoury
Original assignee: Valeo Systemes Thermiques
Priority date: 2010-12-20
Filing date: 2011-12-06
Publication date: 2012-06-28
Also published as: FR2969229B1; FR2969229A1

Abstract

The invention relates to a fan impeller, in particular for cooling the engine that powers a motor vehicle, comprising a central hub (9) and a plurality of blades (11) that are disposed around said hub (9) and extend radially from said hub (9), for swirling an airflow passing through said impeller. According to the invention, said hub (9) has an approximately frustoconical general form, having, in the direction of flow of the air flow, a first, upstream diameter (D₁) and a second, downstream diameter (D₂) greater than said first, upstream diameter (D₁).

Description

Fan propeller and associated cooling module

The invention relates to a fan propeller comprising a central hub and blades extending radially from the hub to the outside of the propeller.

Such a propeller is used in particular for cooling the drive motor of a motor vehicle. In this case, the propeller may be placed upstream or downstream of a heat exchanger, namely a cooling radiator of the drive motor.

According to a known configuration, the helix is disposed between the heat exchanger, or a group of heat exchangers, and the engine block to be cooled in a generally axial alignment. The assembly formed by the heat exchanger (s) (s) and the ventilation system comprising one or more propellers is called cooling module.

The propeller is characterized by the flow of the air flow that it produces, which is used to force the heat exchange between the exchanger and the surrounding air. For this, the ventilation system creates a flow of air that sucks upstream through the exchangers, and which forces the flow of air downstream in the engine compartment.

The distance between the heat exchanger, or all of the heat exchangers when there are several, and the engine block to be cooled can be very small. As a result, the space available to operate an axial ventilation system in the engine compartment is often limited.

This is particularly detrimental because the elements downstream of the ventilation system is an aerodynamic obstacle all the more important as their proximity is great.

The propeller thus sees its performance degraded by the effects of the air flow coming to impact the downstream obstacle formed by the engine block or any other mechanical or structural element of the vehicle.

The effects of degradation of performance by increasing aerodynamic resistance are notable as soon as the distance between the propeller and the obstacle is less than once the diameter of the helix, and become penalizing or critical as soon as the distance is less than once the radius of the helix.

The object of the invention is to overcome these drawbacks of the prior art by proposing an improved fan propeller, so as to avoid performance losses in an axially confined environment.

To this end, the subject of the invention is a fan impeller, in particular for cooling the drive motor of a motor vehicle, comprising a central hub and a plurality of blades arranged around said hub and extending radially from said hub, for stirring a flow of air passing through said helix, characterized in that said hub has a generally frustoconical general shape, and having in the direction of flow of the air flow, a first diameter upstream and a second diameter in downstream higher than said first diameter upstream.

The terms "upstream" and "downstream" refer here to the direction of flow of the airflow.

The frustoconical shape of the hub of the helix, the diameter of which increases in the direction of flow of the air flow passing through the helix, makes it possible to curve this flow of air radially.

This produces a flow having a more or less radial direction to avoid disturbances of a downstream aerodynamic obstacle as caused by the engine block.

This avoids the disturbances caused by the engine block forming a downstream aerodynamic obstacle.

Said propeller may further comprise one or more of the following characteristics, taken separately or in combination:

said second diameter is at least 10% greater than said first diameter;

said second diameter is at least 20% greater than said first diameter;

said hub has a generally substantially funnel-shaped funnel shape;

said blades respectively have a leading edge and a trailing edge, said leading edge of a blade extends from an upstream end of said hub, according to the flow direction of the air flow, close to said first diameter, and said trailing edge of a blade extends from an downstream end of said hub, according to the direction of flow of the air flow near said second diameter;

said helix is made of at least first and second distinct pieces;

said hub is made of a first hub portion and a second hub portion of complementary shapes;

the first part of said propeller comprises said first hub part made in one piece with said blades, and the second part of said propeller comprises said second hub part;

said first hub portion has a plurality of lateral flanks respectively associated with said blades, and said second hub portion has a generally hollow bowl shape having an upstream contour complementary in shape to the peripheral contour of said lateral flanks of said first hub portion;

a lateral flank has a variable height from the leading edge to the trailing edge of the associated blade;

said propeller comprises complementary assembly means carried on the one hand by said at least one first part and on the other hand by said second part; said complementary assembly means are carried on the one hand by the first hub portion and on the other by the second hub portion;

said hub has internal ribs and said complementary assembly means are carried by said internal ribs;

said hub is made by molding.

The invention also relates to a cooling module for a motor vehicle comprising a fan propeller as defined above.

Other features and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings among which: FIG. 1 schematically and schematically illustrates a cooling module of an engine block of a motor vehicle,

FIG. 2 is a first perspective view of a helix of the cooling module of FIG. 1, showing a central hub and blades of the propeller, FIG. 3 is a second perspective view of the propeller, representing the central hub, the blades and a peripheral shell of the propeller,

FIG. 4 is a sectional view partially showing the hub of the propeller,

FIG. 5 is a rear view of the helix,

FIG. 6 is a perspective view of a first piece forming the helix, and FIG. 7 is a perspective view of a second piece forming the helix.

In these figures, the substantially identical elements bear the same references. The invention relates to a fan propeller 1, in particular a propeller 1 of a cooling module 3 for cooling an engine block 5 of a motor vehicle.

As illustrated in FIG. 1, the cooling module 3 comprises a heat exchanger 7 such as a cooling radiator. The propeller 1 may be arranged either in front of or behind the cooling radiator.

According to the embodiment illustrated in Figure 1, the propeller 1 is placed between the cooling radiator 7 and the engine block 5. These elements 1, 5 and 7 are substantially axially aligned.

The propeller 1 is rotatably mounted about an axis A. The direction of rotation of the propeller 1 is indicated by the arrow F in FIGS. 2 and 3. When the propeller 1 is rotated, for example by an electric motor (not shown), the propeller 1 brews the air passing through it. The flow of air flows in a direction of flow oriented substantially from the exchanger 7 to the engine block 5.

The propeller 1 is for example made by plastic injection. This helix 1, better visible in FIGS. 2 and 3, comprises:

a central hub 9, also called "bowl", for example made by molding,

a plurality of blades 11, here five in number, with their first ends 11a around the hub 9, and which extend radially from the hub 9, and

- A peripheral shell 13 to which are connected the second ends 11b of the blades 11.

Referring to FIG. 3, the hub 9 has an upstream end wall 15, with respect to the direction of flow of the air flow produced by the rotation of the propeller 1, and a generally frustoconical wall 17 extending downstream and to which are connected the first ends 11a of the blades 11.

As used herein, the terms "upstream" and "downstream" refer to the flow direction of the airflow. The front wall 15 and the frustoconical wall 17 may be interconnected by a rounded portion 19.

The front wall 15 has a substantially annular shape with a central orifice 21, to allow for example to fix the electric motor (not shown) driving in rotation of the propeller 1. This electric motor (not shown) is generally mounted co -axial to the hub 9 of the propeller 1.

Such an assembly of the electric motor (not shown) to the propeller 1 is known to those skilled in the art of cooling propellers, and is not described in more detail herein.

The frustoconical wall 17 of the hub 9 has an upstream end 17a of first diameter D_i and a downstream end 17b of second diameter D ₂ greater than the diameter Di.

Thus, the hub 9 has a generally frustoconical general shape whose diameter increases with the direction of flow of the air flow with a first small Di diameter upstream and a second diameter D ₂ larger downstream, relative to the direction of flow of the air flow.

This generally frustoconical general shape makes it possible to deflect or curve radially the meridian line of the flow of the air flow to the passage of the helix 1. This gives a semi-radial downstream flow which can bypass the aerodynamic obstacle constituted by the engine block 3 located downstream of the propeller 1.

In order to optimize the inflection of the flow of the air flow, it is possible to provide a diameter variation of the frustoconical shape, greater than 10%, preferably greater than 20%, between the first diameter D 1 upstream and the second diameter D ₂ downstream.

By way of example, a diameter variation of the frustoconical shape of the order of 29% is chosen between the first diameter Di upstream and the second diameter D ₂ downstream. Furthermore, the frustoconical wall 17 may have in addition to the frustoconical shape a substantially curved shape to further promote the inflection of the flow of the air flow.

This substantially frustoconical and curved shape is better visible in the figure

4. Thus the hub 9 may have a generally frustoconical generally curved flared shape. More specifically, the hub 9 then has a general shape of curved funnel.

In addition, according to the exemplary embodiment illustrated in FIG. 4, the frustoconical wall 17 has at its upstream end 17a an angle of deviation α with respect to the axis A of the helix 1, called the angle d input a, zero or relatively low, and has at its downstream end 17b a deviation angle | 3, called exit angle, greater than the entry angle a. This exit angle {3 approaches substantially 90 °.

By way of example, the entry angle a is substantially equal to 10 ° and the exit angle | 3 is substantially equal to 60 °. In addition, the hub 9 may have internal ribs 23, visible on the FIGS. 4 and 5. These internal ribs 23 extend radially with respect to the axis A of the propeller 1 opposite the blades 11. These internal ribs 23 make it possible to stiffen the hub 9.

These internal ribs 23 also serve to force the ventilation inside the hub 9 so as to cool the electric motor (not shown) for driving the propeller 1.

Indeed, when the propeller 1 is rotated, the internal ribs 23 stir the air present inside the hub 9. This air is discharged to the outside of the hub 9 downstream, and moreover, the aerodynamic force induced by the internal ribs 23 makes it possible to suck the air inside the electric motor (not shown) before also discharging it towards the outside of the hub 9.

In addition, the internal ribs 23 of the hub 9 can still be used to allow the assembly of the hub 9 when it is made in two parts 9a, 9b complementary as will be described later.

As regards the blades 11, they extend from the frustoconical wall 17 of the hub 9 to the peripheral shell 13 (see FIG. 3). These blades 11 are generally identical. These blades 11 may present respectively as in the illustrated example a cross section substantially in the air wing.

The blades 11 respectively have a leading edge 25 which first comes into contact with the air flow at the rotation of the propeller 1, and an opposite trailing edge 27. The blades 11 may present respectively a generally substantially curved shape of the leading edge 25 at the trailing edge 27. The blades 11 may further have an aerodynamic profile with leading edges 25 and trailing 27 rounded contour without a protruding angle.

Alternatively or in addition the blades 11 may have a thickness that varies continuously.

The leading edge 25 of a blade 11 extends from the upstream end 17a of the frustoconical wall 17 of the hub 9, to the shell 13. The leading edge 25 is thus connected to the hub 9 near the smallest diameter Di and extends to the ferrule 13.

The trailing edge 27 extends from the downstream end 17b of the frustoconical wall 17 of the hub 9, to the shell 13. The trailing edge 27 is thus connected to the hub 9 near the largest diameter D ₂ and extends to the ferrule 13.

Thus, the diameter of the frustoconical shape of the hub 9 grows from the leading edge 25 to the trailing edge 27 of a blade 11.

In addition, the leading and trailing edges 27 define between them a rope 29 (shown in phantom), that is to say a straight segment which extends between the leading edge 25 and the edge. leakage 27.

According to the illustrated embodiment, this rope 29 is inclined at an acute angle with respect to a radial plane, that is to say substantially perpendicular to the axis A of the helix 1. This angle can vary on the length of the blade 11, from the end 11a of the blade 11 fixed to the hub 9 to the end 11b of the blade 11 attached to the shell 13.

The shell 13, in turn, has a cylindrical annular wall of revolution 31, which is connected to the ends of the blades 11, and which continues, by a rounded flare 33. Furthermore, it can be provided to achieve the helix 1 in two parts: a first part shown in Figure 6 and a second part lb shown in Figure 7.

According to the illustrated embodiment, the first part 1a (FIG. 6) comprises the shell 13, the blades 11 and a first part 9a of the hub 9. And the second part 1b (FIG. 7) has a second part 9b of the hub 9 complementary to the first part 9a to form the hub 9 as described above.

The first part 9a (FIG. 6) of the hub 9 thus has, opposite to the end wall 15, a peripheral contour 35 of complementary shape to the second part 9b of the hub 9, to form a hub 9 of generally frustoconical shape, as previously described. In addition, the first part 9a of the hub 9 being made in one piece with the blades 11, the first part 9a has a shape complementary to the first ends 11a of the blades 11 fixed to the hub 9.

As previously described, the leading edge 25 of a blade 11 is close to the smallest diameter Di of the frustoconical hub 9 and the trailing edge 27 is close to the largest diameter D ₂ of the frustoconical hub 9 (FIG. 3). Consequently, the first part 9a (FIG. 6) does not have the same amount of material from the leading edge 25 to the trailing edge 27 of a blade 11.

Indeed, the first part 9a has, according to the example illustrated, lateral flanks 37 respectively associated with the blades 11, more precisely as many lateral flanks 37 as blades 11, and whose height h varies from the leading edge 25 to the edge leakage 27 of the associated blade 11.

The lateral flanks 37 thus extend from the front wall 15 or for example from the flare 19, according to the general direction of flow of the air flow and according to a variable height h of the leading edge 25 at the trailing edge. 27 of the associated blade 11.

In addition, the blades 11 may have a generally curved general shape of the leading edge 25 at the trailing edge 27. Thus, the lateral flanks 37 may have substantially curved edges 39 of the leading edge 25 at the trailing edge 27 of a blade 11.

The second portion 9b of the hub 9 is complementary to the first portion 9a so that the parts 9a, 9b assembled have a generally frustoconical general shape to form the hub 9 as described above.

For this purpose, the second portion 9b has for example a generally hollow bowl shape with an upstream contour 41 of shape complementary to the contour 35 of the first part 9a and a downstream contour 43 defining the downstream end 17b of the diameter hub 9 D ₂ higher.

Moreover, as mentioned above, the hub 9 may have internal ribs 23 to stiffen the hub 9 and used in particular for the ventilation of the hub 9. electric motor (not shown) for driving the propeller 1.

In this case where the hub 9 is made in two parts 9a, 9b hub, each hub portion 9a, 9b have complementary internal ribs 23a, 23b respectively forming the assembly of the two hub portions 9a, 9b, the ribs internals 23 of the hub 9.

In the example illustrated in Figures 5 and 6, the inner ribs 23a of the first hub portion 9 have a generally substantially L-shaped, respectively. This embodiment of the two-piece propeller 1a, 1b is advantageous to allow axial demolding due to the frustoconical shape of the hub 9 and the presence of the blades 11 extending radially from the frustoconical hub 9 outwardly of the propeller 1. Indeed, demolding in a single axial direction is not possible if the frustoconical hub 9 is made in one piece with the blades 11 extending from the hub 9.

On the other hand, the two parts 1a, 1b of the propeller 1 can be produced while respecting an axial demoulding.

For this purpose, it is possible to provide, for example, the same two-cavity mold for producing the two parts 1a, 1b by plastic injection with axial demolding.

The two pieces 1a, 1b can then be assembled (FIG. 5) by any known assembly method. Non-exhaustive methods include screwing, gluing, thermo-bonding, ultrasonic welding, clipping, press fitting, wedging using the drive shaft of the electric motor. These methods are not described in more detail.

For this purpose, each portion 9a, 9b of the hub 9 may carry complementary assembly means.

According to the embodiment illustrated in FIGS. 5 to 7, advantage is taken of the presence of the internal ribs 23 of the hub 9. By way of example, provision can be made for fastening the two hub portions 9a, 9b by screwing using the internal ribs 23, more precisely the internal ribs 23a, 23b complementary to each hub portion 9a, 9b.

Indeed, as noted in the example illustrated in Figure 5, there may be associated housing 45a, 45b provided to receive a fixing screw (not shown). These housings 45a, 45b associated are respectively provided in the internal ribs 23a, 23b of each hub portion 9a, 9b.

In addition, it is possible to provide on the downstream portion internal ribs 23b of the second hub portion 9b, recesses 47 at the housings 45b so as to receive the screw heads (not shown).

These recesses 47 have for example a substantially rectangular shape.

The dimensions of these recesses 47 are advantageously chosen so that the screw heads (not shown) do not protrude from the hub 9. The screws (not shown) are therefore "embedded".

Thus, a propeller 1 having a frustoconical hub 9 as described above makes it possible to radially bend the flow of the air flow passing through the propeller in an axial arrangement of the cooling module 3 and the engine block 5 to be cooled. The resulting semi-radial downstream flow bypasses the obstacle formed by the engine block 5 placed in the axis of the helix 1; this prevents the engine block 5 diverting the air flow.

In addition, conventional axial flow propellers are characterized by a high flow rate but a low pressure. For flow conditions equal to a downstream aerodynamic obstacle, the pressure generated by the helix 1 as defined above allowing a semi-radial downstream flow is greater than that of a conventional propeller with a solely axial flow.

In addition, the embodiment of the propeller 1 in two parts 1a, 1b makes it possible to produce the propeller 1 according to a conventional method by plastic injection and by axial demolding.

Claims

Fan propeller, especially for cooling the drive motor of a motor vehicle, comprising a central hub (9) and a plurality of blades

(11) arranged around said hub (9) and extending radially from said hub (9), for stirring a flow of air passing through said propeller, characterized in that said hub (9) has a generally frustoconical general shape, and having in the direction of flow of the air flow, a first diameter (Di) upstream and a second diameter (D ₂ ) downstream greater than said first diameter (Di) upstream.

2. Propeller according to claim 1, characterized in that said second diameter (D ₂ ) is at least 10% greater than said first diameter (Di).

3. Propeller according to one of claims 1 or 2, characterized in that said hub (9) has a generally substantially funnel-shaped funnel.

4. Propeller according to any one of the preceding claims, characterized in that said blades (11) respectively have a leading edge (25) and a trailing edge (27), and in that:

said leading edge (25) of a blade (11) extends from an upstream end (17a) of said hub (9), in the direction of flow of the air flow, in the vicinity of said first diameter (Di), and

- said trailing edge (27) of a blade (11) extends from a downstream end (17b) of said hub (9), in the direction of flow of the air flow, close to said second diameter (D ₂ ).

5. Propeller according to any one of the preceding claims, characterized in that said propeller is made of at least a first (la) and a second (lb) separate pieces.

6. Propeller according to any one of the preceding claims, characterized in that said hub (9) is made of a first (9a) hub portion and a second (9b) hub portion of complementary shapes.

7. Propeller according to claim 5 taken in combination with claim 6, characterized in that the first piece (la) of said propeller comprises said first hub part (9a) made in one piece with said blades (11), and the second piece (1b) of said propeller comprises said second hub portion (9b).

8. Propeller according to claim 7, characterized in that: - said first hub portion (9a) has a plurality of side flanks (37) respectively associated with said blades (11), and in that

- Said second hub portion (9b) has a generally hollow bowl shape having an upstream contour (41) complementary shape of the peripheral contour (35) of said side flanks (37) of said first hub portion (9a).

9. Propeller according to claim 4 taken in combination with claim 8, characterized in that a lateral flank (37) has a variable height (h) from the leading edge (35) to the trailing edge (37) of the associated blade (11).

10. Propeller according to any one of claims 5 to 9, characterized in that said propeller comprises complementary assembly means (45a, 45b) carried on the one hand by said at least a first piece (la) and of secondly by said second piece (1b).

11. Propeller according to any one of claims 7 to 9 taken in combination with claim 10, characterized in that said complementary assembly means (45a, 45b) are carried on the one hand by the first part (9a) of hub and secondly by the second hub portion (9b).

12. Propeller according to claim 11, characterized in that said hub (9) has internal ribs (23) and in that said complementary assembly means (45a, 45b) are carried by said internal ribs (23).

13. Propeller according to any one of the preceding claims, characterized in that said hub (9) is made by molding.

14. Cooling module for a motor vehicle characterized in that it comprises a fan propeller (1) according to any one of the preceding claims.