SUPPORT FRAME

Description

Domaine technique

[0001] The present invention relates to the field of automobiles, and more particularly to that of air circulation for cooling an engine. Technique antérieure

[0002] According to the state of the art, motor vehicles evacuate the calories generated by their operation and are therefore equipped with heat exchangers, in particular cooling radiators, placed for example at the front of the vehicle and crossed for example by outside air. To force the circulation of this air through the exchanger(s), a fan is placed upstream or downstream. A propeller can be used to force the circulation of air. In certain examples, the propeller generates a relatively high flow rate and a relatively low pressure and has an axially oriented flow, that is to say in the direction of an axis of rotation of the propeller.

[0003] Document WO2016 / 199195A1 describes a support frame for a ventilation device for cooling a fluid flowing through a cooling circuit of a motor vehicle according to the preamble of claim 1. Résumé

[0004] The present invention is defined by the appended independent claims. Other features and advantages arising from the concepts disclosed herein are set forth in the following description. They will be apparent in part from the description or may be acquired by practice of the disclosed technologies. The features and advantages of these concepts may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosed technologies will be more fully apparent from the following description and the appended claims, or may be inferred from practice of the concepts set forth herein.

[0005] The present disclosure describes a support frame for a ventilation device for cooling a fluid flowing through a cooling circuit of a motor vehicle, said frame comprising an opening defining an opening perimeter, the opening being intended to receive a propeller, and a central support positioned at the center of said opening and shaped to receive a motor actuating said propeller so as to generate a ventilation flow, said central support being attached, through said opening, to the frame by at least six holding arms, at least three first holding arms being placed in a first plane or cone of revolution (or cone in this disclosure), and at least three second holding arms being placed in a second plane or cone of revolution different from the first plane or cone of revolution,the first holding arms each being separated from any second holding arm at the opening perimeter by a space covering at least a distance corresponding to a chord of said first holding arms.,

[0006] A structure as described makes it possible to reinforce the frame by distributing the support network formed by the support arms, while allowing the flow to flow between the support arms. This reinforcement of the frame can make it possible to reduce stresses linked to the shape of said support arms, or to avoid a so-called pumping phenomenon corresponding to an unwanted periodic movement of the central support in the direction of the axis of rotation of the propeller caused by an oscillation of the support arms.

[0007] In some embodiments, the first holding arms are placed in a first plane and the second holding arms are placed in a second plane parallel to the first plane. This distribution of the holding arms in different planes makes it possible to stiffen the holding structure of the central support, any oscillation of the holding arms placed in the first plane being compensated or avoided by the holding arms placed in the second plane. Such a structure in fact improves the axial rigidity of the frame in the rotational axis of the propeller.

[0008] In some embodiments, the first holding arms are placed in a first cone of revolution and the second holding arms are placed in a second cone of revolution different from the first cone of revolution. Such a structure allows, by using different angles between the first and second holding arms on the one hand, and the axis of rotation of the propeller on the other hand, a mechanical compensation limiting the aforementioned pumping effect, any movement of the first arms being at least partly compensated by a tension generated by the second arms, and vice versa. In some particular cases, the first holding arms form a first angle with a plane defined by the opening, the second holding arms forming a second angle with the plane defined by the opening, the first and second angles being of the same sign.Such an arrangement may limit the pumping phenomenon while facilitating a demolding process without draft due to the use of angles going in the same direction. In certain particular cases, the first holding arms form a first angle with a plane defined by the opening, the second holding arms form a second angle with the plane defined by the opening, the first and second angles being of opposite signs. This arrangement may allow interlacing between the first and second holding arms allowing an improvement in torque transfer between the central support and the opening perimeter.

[0009] In some embodiments, each first holding arm is separated from another first holding arm by at least one second holding arm. Such a distribution makes it possible to improve the rigidity of the assembly, a tension on the first holding arms being compensated by a second holding arm placed between them.

[0010] In some embodiments, the first holding arms form groups of first holding arms succeeding one another along the opening perimeter, each group of first holding arms being separated from another group of first holding arms at least by a second holding arm or by a group of second holding arms. Such a distribution allows partial interlacing between the first and second holding arms, such partial interlacing making it possible to simplify the structure while benefiting from a distribution between the first and second holding arms along the opening perimeter.

[0011] In some embodiments, the first and second support arms are regularly distributed along the opening perimeter. This facilitates balancing of the structure which will help to reduce or avoid the pumping phenomenon.

[0012] In some embodiments, the opening has a ring shape, the ring comprising three complementary sectors, each complementary sector covering 120 degrees of the ring, each complementary sector comprising the same number of first and second holding arms. Such a distribution makes it possible to obtain a particularly well-balanced structure leading to facilitating regular rotation of the assembly.

[0013] In some embodiments, the support arms have an aerodynamic shape. Such a shape allows the support arms not only to fulfill a role as support for the central support, but also to contribute to the generation of the cooling flow by cooperating with an aerodynamic shape of the propeller blades.

[0014] In some embodiments, the holding arms have a double-twisted aerodynamic shape. Such a shape has a particularly positive effect on the generation of the desired cooling flow. The mechanical flexibility introduced by the use of such a shape is compensated by the rigidity of an arrangement of the holding arms such as in the present description.

[0015] In some embodiments, each holding arm is connected to the frame by a corresponding stud, said studs extending perpendicular to the opening, some of said studs connected to the first holding arms having a first height perpendicular to the opening and from a plane comprising the opening, some others of said studs connected to the second holding arms having a second height perpendicular to the opening and from the plane comprising the opening, the first height being different from the second height. Such an arrangement of studs allows the placement of the first and second arms at different heights at a connection location with the frame in order to obtain a structure as described, while allowing passage of the flow between the studs.

[0016] The present disclosure also describes a ventilation device comprising a propeller whose motor is carried by the support frame according to the present description. Such a device may, for example, allow synergy between the shape of the propeller and the shape and position of the holding arms as described.

[0017] The present disclosure also describes a cooling module for the thermal engine of a motor vehicle comprising the ventilation device as described, the cooling module being able to implement an aerodynamic synergy between its different components, in particular the holding arms as described. Brève description des dessins

[0018] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Fig. 1A [ Fig. 1A ] is an example representation of a support frame according to the present disclosure. Fig. 1B [ Fig. 1B ] is an example representation of a section of a support frame as represented by the Figure 1A . Fig. 1C [ Fig. 1C ] is an example representation of a section of a support frame as represented by the Figure 1A . Fig. 1D [ Fig. 1D ] is an example representation of a section of a support frame as represented by the Figure 1A . Fig. 1E [ Fig. 1E ] is an example representation of a section of a support frame as represented by the Figure 1A . Fig. 1F [ Fig. 1F ] is an example representation of a support frame according to the present disclosure. Fig. 2A [ Fig. 2A ] is an example representation of a support frame according to the present disclosure. Fig. 2B [ Fig. 2B ] is a representation of a part of the armature represented by the Figure 2A . Fig. 3 [ Fig. 3 ] is a representation of an example of a ventilation device according to the present disclosure. Fig. 4 [ Fig. 4 ] is a representation of an example of a cooling module according to this disclosure. Description des modes de réalisation

[0019] This disclosure relates to a support frame for a ventilation device for cooling a fluid flowing through a cooling circuit of a motor vehicle. This frame may in certain cases be integrated into a motor-fan unit or GMV. The motor vehicle may have thermal or electric propulsion, or hybrid propulsion. This frame may correspond to a base comprising a nozzle. This frame may have a generally parallelepiped shape, for example having external dimensions of between 1 and 8 cm thick in the axial direction of rotation of the propeller, and dimensions of between 20 and 60 cm on each side in a plane normal to said axial direction.This frame may have a generally parallelepiped shape, for example having external dimensions of between 2 and 6 cm thick in the axial direction of rotation of the propeller, and dimensions of between 45 and 55 cm on each side in a plane normal to said axial direction.

[0020] The frame according to this disclosure comprises an opening defining an opening perimeter, the opening being intended to receive a propeller. Such an opening may have a generally circular opening perimeter having a diameter for example between 30 and 50 cm. Such an opening may have a generally circular opening perimeter having a diameter for example between 35 and 45 cm. Such an opening may have a generally circular opening perimeter having a diameter for example between 38 and 42 cm. This opening allows the circulation of a flow such as an air flow generated by the rotation of the propeller. In some examples, the shape of the opening corresponds to the shape of the propeller, the opening opening in a plane normal to the axis of rotation of the propeller. In some cases, the opening has a generally ring-shaped shape having an opening perimeter corresponding to the outer perimeter of the ring.

[0021] The opening perimeter determines the wall of a hollow cylindrical cavity in which the propeller is positioned, the cylindrical cavity having an axis corresponding to the axial direction or axis of rotation of the propeller. The armature can provide attachment to a support, for example a cooling radiator or a vehicle chassis, as well as the support of an electric motor for driving the propeller and the maintenance of the axis around which it rotates. Furthermore, from an aerodynamic point of view, the armature can form a wall and limit or prevent recirculation between the upstream and downstream sides of the propeller. The attachment of an electric motor to the armature can be made up of several holding arms having a mechanical holding function. Such holding arms can take the form of an aircraft wing, or stator blades giving them an aerodynamic function beyond their mechanical function. The stator blades allow, for example, a straightening of the flow.

[0022] The frame according to this disclosure comprises a central support positioned at the center of said opening. The center of the opening may correspond to the center of a circle corresponding to a perimeter of the opening. The center of the opening may comprise the location where the axis of rotation of the propeller intersects a plane comprising the opening. This central support is shaped to receive a motor actuating said propeller so as to generate a ventilation flow or stream. The frame according to this disclosure not only makes it possible to define a nozzle through which the flow generated by the propeller flows but also makes it possible to anchor a motor such as an electric motor actuating the propeller.

[0023] Said central support is attached, through said opening, to the frame by at least six holding arms. Such holding arms have a mechanical function allowing the central support to be attached to the periphery of the frame through the opening. In order to ensure a certain rigidity of the assembly, the number of holding arms must be sufficient. Each holding arm forms a bridge between the central support and the peripheral part of the frame defining the opening. Each holding arm has two ends, one end being connected to the central support, the other end being connected, possibly by means of a stud, to the perimeter of the opening. Between the two ends, the holding arms extend radially from the axis of rotation of the propeller. In certain cases, said central support is attached, through said opening, to the frame by at least eight holding arms.In some cases, said central support is attached, through said opening, to the frame by at least ten holding arms. In some cases, said central support is attached, through said opening, to the frame by at least twelve holding arms. The use of a higher number of holding arms may contribute to a better mechanical balance of the assembly, and may provide increased freedom to use particularly aerodynamic shapes for said holding arms.

[0024] Such support arms have a mechanical role of supporting a central support. Due to the fact that such support arms pass through the opening and are therefore in the flow generated by the propeller, the support arms have an influence on the aerodynamics of the assembly. It is therefore desirable in certain cases to adapt, for example, the shape of the support arms to the aerodynamics of the assembly. This can have consequences on the mechanical characteristics of the support arms. A compromise must therefore be reached in certain cases in order, on the one hand, to obtain appropriate mechanical characteristics for the support arms, and on the other hand to use a particularly aerodynamic shape for them. The support frame according to the present disclosure makes it possible to resolve this compromise by improving the rigidity of the structure by a differentiated positioning of the support arms as described.Such differentiated positioning makes it possible in particular to limit a phenomenon known as "pumping" consisting under certain conditions of an unwanted periodic movement of the central support in the direction of the axis of rotation of the propeller, due to excessive flexibility of the holding arms. The differentiated positioning of the holding arms as described in this disclosure makes it possible to reduce the occurrence of such "pumping". Such differentiated positioning makes it possible to improve the rigidity of the assembly and therefore to provide increased freedom as to the choice of the shape of the holding arms, for example by allowing the use of lightweight holding arms or those having a particularly thin and aerodynamic shape.

[0025] According to this disclosure, at least three first holding arms are placed in a first plane or cone of revolution, and at least three second holding arms are placed in a second plane or cone of revolution different from the first plane or cone of revolution. This differentiated placement of the holding arms allows the improvement of the rigidity of the structure limiting the aforementioned pumping phenomenon. It is possible that this improvement in rigidity is obtained by the fact that a natural vibration frequency of the first holding arms is different from a natural vibration frequency of the second holding arms, leading to a synergetic stabilization of the assembly and therefore to a limitation or even a suppression of the unwanted pumping phenomenon. The introduction of such a difference in positioning provides increased freedom as to the choice of the shape or even the materials used for the holding arms for a given rigidity of the structure.The use of the same first plane or cone of revolution for the first three holding arms makes it possible to obtain a certain homogeneity of placement of the first three holding arms contributing to the mechanical stability of the assembly, as well as its ease of manufacture. Similarly, the use of the same second plane or cone of revolution for the second three holding arms makes it possible to obtain a certain homogeneity of placement of the first three holding arms contributing to the mechanical stability of the assembly, as well as its ease of manufacture. In certain cases, the first cone of revolution has as its axis the axis of rotation of the propeller corresponding to the center of the opening perimeter. In certain cases, the second cone of revolution has as its axis the axis of rotation of the propeller corresponding to the center of the opening perimeter. In certain cases, the first plane is parallel to a plane comprising the perimeter of the opening.In some cases, the second plane is parallel to a plane including the perimeter of the opening. In some cases, the number of first holding arms is equal to the number of second holding arms. In some cases, the number of first holding arms is greater than the number of second holding arms. In some cases, the number of first holding arms is less than twice the number of second holding arms. In some cases, the number of first holding arms is less than three times the number of second holding arms.

[0026] According to this disclosure, the first holding arms are each separated from any second holding arm at the opening perimeter by a space covering at least a distance corresponding to a chord of said first holding arms. Arranging such a space between the first holding arms and each second holding arm makes it possible, on the one hand, to obtain satisfactory mechanical behavior of each type of holding arm, preventing an extreme proximity of a first and a second holding arm from leading to behavior similar to a single split holding arm, which would not make it possible to obtain the structural rigidity behavior sought in this disclosure. A chord of said first holding arms corresponds, for example, to a thickness of a first holding arm in a direction tangent to the opening perimeter, corresponding to an angular direction of movement of the rotating propeller.This chord can be measured at different points along the support arm, at different distances from the propeller's axis of rotation. The distance corresponding to this chord can therefore vary for a specific first support arm. In some cases, the chord considered is the average chord of the different chords of the first support arm considered. In some cases, the chord considered is the median chord of the different chords of the first support arm considered. In some cases, the chord considered is the maximum chord of the different chords of the first support arm considered. In some cases, the chord considered is the minimum chord of the different chords of the first support arm considered. In some cases, the chord considered is the chord of the first support arm considered at the point where it is attached to the perimeter of the opening, opposite the central support.In some cases, the chord considered is the chord of the first holding arm considered at the location of its attachment to the central support. The distance corresponding to the chord considered is related to the opening perimeter in order to determine the distance that must separate the first holding arm from any second holding arm. It is understood that the same first holding arm will be closer to any second holding arm at the central support, due to the structure of the assembly. This spacing, beyond mechanical consequences, allows flow between the holding arms considered. In some cases, the first holding arms are each separated from any second holding arm at the opening perimeter by a space covering at least twice a distance corresponding to a chord of said first holding arms.In some cases, the first holding arms are each separated from any second holding arm at the opening perimeter by a gap spanning at least three times a distance corresponding to three times one to one chord of said first holding arms. In some cases, the first holding arms are each separated from any second holding arm at the opening perimeter by a gap spanning at least four times a distance corresponding to three times one to one chord of said first holding arms.

[0027] There Figure 1A represents a frame according to the present disclosure represents a support frame 100 of a ventilation device for cooling a fluid flowing through a cooling circuit of a motor vehicle, said frame 100 comprising an opening defining a circular opening perimeter 103, the opening being intended to receive a propeller not shown, and a cylindrical central support 102 positioned at the center of said opening and shaped to receive a motor, not shown, actuating said propeller so as to generate a ventilation flow, said central support 102 being attached, through said opening, to the frame by six holding arms 111-116, at least three first holding arms 111, 113, 115 being placed in a first plane or cone of revolution, and at least three second holding arms 112, 114, 116 being placed in a second plane or cone of revolution different from the first plane or cone of revolution,the first holding arms each being separated from any second holding arm at the opening perimeter by a space 131 covering at least a distance corresponding to a chord of said first holding arms.,

[0028] In the configuration of the Figure 1A , the frame comprises first arms 111, 113 and 115 alternating with second arms 112, 114 and 116. In other words, each first holding arm is separated from another first holding arm by a second holding arm. Such a configuration is mechanically particularly balanced.

[0029] In some cases, each first holding arm is separated from another first holding arm by at least one second holding arm.

[0030] The frame may include additional holding arms that are neither first nor second holding arms, such additional holding arms having their own configuration and placement.

[0031] The armature represented by the Figure 1A can have a number of different configurations.

[0032] There Figure 1B represents a possible section of the reinforcement according to the section S of the Figure 1A in a plane perpendicular to the view of the Figure 1A comprising the first holding arm 115 and the second holding arm 112. In this case, the first holding arms such as the first holding arm 115 are placed in a first plane 141. In this case, the second holding arms such as the second holding arm 112 are placed in a second plane 142. It is of course understood in this disclosure that the "placement" of a holding arm "in" a plane or cone of revolution implies the placement of a general axis of such holding arm in such an arm or cone, and not of the arm itself, a plane or cone having in theory a zero thickness. Such a general axis of the arm can correspond to a theoretical straight line segment joining the end of the corresponding arm in contact with the central support and the opposite end of the same arm in contact with the perimeter of the opening.In this example, the first plane and the second plane are planes normal to the axis 101 of rotation of the propeller or central axis of the frame or central axis of the central support. The distance separating the first and second planes may in certain cases be at least the thickness of a first holding arm measured at the junction of such first holding arm with the opening perimeter in the direction of rotation of the propeller. The distance separating the first and second planes may in certain cases be at least twice the thickness of a first holding arm measured at the junction of such first holding arm with the opening perimeter in the direction of rotation of the propeller.The distance separating the first and second planes may in some cases be at least three times the thickness of a first holding arm measured at the junction of such first holding arm with the opening perimeter in the direction of rotation of the propeller. An increased difference between said planes may contribute to mechanical stability. An excessive distance may make the size of the frame excessive. The distance separating the first and second planes may in some cases be at most four times the thickness of a first holding arm measured at the junction of such first holding arm with the opening perimeter in the direction of rotation of the propeller.The distance separating the first and second planes may in certain cases be at most three times the thickness of a first holding arm measured at the junction of such first holding arm with the opening perimeter in the direction of rotation of the propeller.

[0033] There Figure 1C represents a possible section of the reinforcement according to the section S of the Figure 1A in a plane perpendicular to the view of the Figure 1A comprising the first holding arm 115 and the second holding arm 112. In this case, the first holding arms such as the first holding arm 115 are placed in a first cone partially represented by the generatrix 151 of the first cone, the axis of the cone being the axis 101 of rotation of the propeller. In this case, the second holding arms such as the second holding arm 112 are placed in a second cone partially represented by the generatrix 152 of the second cone, the axis of the cone being the axis 101 of rotation of the propeller. The first cone of revolution is different from the second cone in order to obtain the effect sought in this disclosure. In this example, the first cone and the second cone are cones having the same axis 101 of rotation of the propeller or central axis of the frame or central axis of the central support.In this example, the first holding arms form a first angle 161 with a plane 104 defined by the opening, the second holding arms form a second angle 162 with the plane 104 defined by the opening, the first and second angles being of the same opposite sign.

[0034] In some cases, the first angle and the second angle differ by at least 5 degrees. In some cases, the first angle and the second angle differ by at least 10 degrees. In some cases, the first angle and the second angle differ by at least 15 degrees. In some cases, the first angle and the second angle differ by at least 20 degrees. In some cases, the first angle and the second angle differ by at least 30 degrees. In some cases, the first angle and the second angle differ by at least 45 degrees. In some cases, the first angle and the second angle differ by less than 90 degrees. In some cases, the first angle and the second angle differ by less than 60 degrees. An increased difference between said first and second angles may contribute to mechanical stability. An excessive difference may make the reinforcement bulky. The first or second angle may be between -5 and +5 degrees.The first or second angle can be between -15 and +15 degrees. The first or second angle can be between -20 and +20 degrees. The first or second angle can be between -30 and +30 degrees.

[0035] There Figure 1D represents a possible section of the reinforcement according to the section S of the Figure 1A in a plane perpendicular to the view of the Figure 1A comprising the first holding arm 115 and the second holding arm 112. In this case, the first holding arms such as the first holding arm 115 are placed in a first cone partially represented by the generatrix 153 of the first cone, the axis of the cone being the axis 101 of rotation of the propeller. In this case, the second holding arms such as the second holding arm 112 are placed in a second cone partially represented by the generatrix 154 of the second cone, the axis of the cone being the axis 101 of rotation of the propeller. The first cone of revolution is different from the second cone in order to obtain the effect sought in this disclosure. In this example, the first cone and the second cone are cones having the same axis 101 of rotation of the propeller or central axis of the frame or central axis of the central support.In this example, the first holding arms form a first angle 163 with a plane 104 defined by the opening, the second holding arms form a second angle 164 with the plane 104 defined by the opening, the first and second angles being of opposite signs.

[0036] There Figure 1E represents a possible section of the reinforcement according to the section S of the Figure 1A in a plane perpendicular to the view of the Figure 1A comprising the first holding arm 115 and the second holding arm 112. In this case, the first holding arms such as the first holding arm 115 are placed in a cone partially represented by the generatrix 155 of the first cone, the axis of the cone being the axis 101 of rotation of the propeller. In this case, the second holding arms such as the second holding arm 112 are placed in a plane 144 parallel to the plane comprising the opening.

[0037] There Figure 1F represents an example of armature 105 similar to the example represented by the Figure 1A , the frame 105 comprising six first holding arms 117 and six second holding arms 118, the first holding arms 117 forming groups of two first holding arms succeeding one another along the opening perimeter, each group of first arms of two holding arms 117 being separated from another group of two first holding arms 117 at least by a group of second holding arms 118.

[0038] In some cases, such as in the case represented by the Figure 1F , the first holding arms form groups of first holding arms succeeding one another along the opening perimeter, each group of first holding arms being separated from another group of first holding arms at least by a second holding arm or by a group of second holding arms. This makes it possible to increase the number of holding arms while maintaining a homogeneous structure.

[0039] In some cases, as represented for example by the Figures 1A , 1F Or 2A , the opening has a ring shape, the ring comprising three complementary sectors, each complementary sector covering 120 degrees of the ring, each complementary sector comprising the same number of first and second holding arms. Taking as an example the frame 105 represented by the Figure 1F , the ring forming the opening is defined by the circumference of the central support 102 and by the opening perimeter 103. On this same Figure 1F , three complementary sectors of 120 degrees of this ring are limited by the axes 160. Each of these three sectors shown comprises four holding arms, an equal number of first holding arms and second holding arms, precisely in this case two holding arms 117 and two holding arms 118 per sector. This provides a balanced structure, avoiding or reducing vibrations during a propeller rotation movement. In some cases, the ring comprises six complementary sectors, each complementary sector covering 60 degrees of the ring, each complementary sector comprising an equal number of first and second holding arms.

[0040] In some cases, such as for example illustrated by the frame 200 of the Figure 2A , the holding arms have an aerodynamic shape, such as the twelve holding arms 210-221 between the opening perimeter 203 and the central support 202 of the frame 200. This can improve the flow obtained by the use of the frame by adding to the holding arms an aerodynamic role beyond their role as mechanical supports. The holding arms 210-221 comprise six first holding arms 211, 213, 215, 217, 219, and 221 and six second holding arms 210, 212, 214, 216, 218, and 220. In this case, the first and second holding arms are alternated. In this case, as illustrated in more detail in the Figure 2B , the first holding arms are attached to a first level N1 of the central support, the second holding arms being attached to a second level N2 of the central support, the level N1 being different from the level N2 along an axis 201 of propeller rotation, said axis 201 being normal to a plane comprising the opening. In this case, as illustrated further on the Figure 2B , the first holding arms are attached to a third level N3 of the central support, the second holding arms being attached to a fourth level N4 of the central support, the level N3 different from the level N4 along the propeller rotation axis 201. These level offsets lead to producing an example according to this disclosure avoiding placing all the holding arms in the same plane or cone of revolution in order to obtain a particularly rigid structure, particularly effective in a case of using aerodynamically shaped holding arms tending to be more flexible.

[0041] In some cases, each holding arm is connected to the frame by a corresponding pad, said pads extending perpendicular to the opening, some of said pads connected to the first holding arms having a first height perpendicular to the opening and from a plane comprising the opening, some others of said pads connected to the second holding arms having a second height perpendicular to the opening and from the plane comprising the opening, the first height being different from the second height. The use of such pads can facilitate the generation of a flow in the radial direction passing between consecutive pads.

[0042] In the case of the armature represented by the Figures 2A et 2B , each holding arm 210-221 is linked to the frame 200 by a corresponding stud, said studs extending perpendicular to the opening, some of said studs linked to the first holding arms having a first height, corresponding to level N3, perpendicular to the opening and from a plane comprising the opening, some others of said studs linked to the second holding arms having a second height, corresponding to level N4, perpendicular to the opening and from the plane comprising the opening, the first height being different from the second height.

[0043] An aerodynamic shape may include a leading edge and a trailing edge, with a flow incident on the leading edge, the flow following a lower and upper surface. The lower and upper surfaces meet at the trailing edge beyond which the flow flows. An aerodynamic shape includes a chord line and a camber line, the chord line following a straight line joining the leading edge and the trailing edge, the camber line being a curve joining the leading edge and the trailing edge, the camber line being a curve midway between the lower and upper surfaces. A leading edge continues to a point of maximum thickness.

[0044] In some cases, the support arms have a particularly aerodynamic double-twisted shape.

[0045] The support arms 210-221 have, for example, a double-twisted shape which aims to reduce drag due to air friction against said support arms during the operation of a propeller. Such arms can take on, beyond their mechanical function, a dual aerodynamic and acoustic function. Instead of arms in the form of flat plates oriented in the direction of the flow passing through the propeller, aerodynamically shaped support arms are in certain cases constituted by thin blades, of large span and elongated section, with a chord whose length is at least 1.5 times greater than that of their thickness, in particular at their point of greatest thickness. These support arms have an aerodynamic profile to reduce their drag, and a setting of the profile evolves throughout their span, between their foot carried by the central support 202 and their head connected to the opening perimeter 203.The setting of the section profile of a said support arm can for example evolve along their span, starting from a substantially radial orientation at its foot and the central support 202, to arrive at a significantly more axial orientation at mid-span of the support arm, and to return to a substantially radial orientation at its head and the opening perimeter 203. The law of the setting, that is to say of the angle that the chord of this section makes with the axial direction of rotation of the propeller, normal to the plane defined by the opening, is scalable along the span to adapt to the direction and the gyration of the flow at the propeller outlet. This is beneficial both for aerodynamic efficiency and for the reduction of instabilities which generate noise.In certain cases the root pitch, as well as the tip pitch, has a significant value (for example greater than 70°), whereas the central part of the blade, i.e. that between 25 and 75% of the span, has a relatively low pitch (for example less than 20°). The support arms 210-221 have for example a doubly twisted shape all along a line connecting the mid-chord points of the support arm, the twist being constituted by a rotation of the stator section, in a tangential plane, when this line is described from the root to the tip of the support arm. It is said to be doubly twisted because the twist increases from the root towards mid-span, to decrease from mid-span towards the tip and return to a slightly twisted level. According to an embodiment not illustrated, the evolution of the pitch could be interrupted, or follow another law, in the central part of the stator.Such a double twisted shape reduces the rigidity of the arms which therefore benefit particularly from the different configurations as described in this presentation.

[0046] In some cases, the first support arms join the central support at a first level of a propeller rotation axis and the second support arms join the central support at a second level of a propeller rotation axis, the first level and the second level being separated by at least 50% of the maximum thickness of a first support arm, the thickness being measured along the span of the support arm (or stator), without taking into account its ends.

[0047] In some cases, the first holding arms join the opening perimeter at a first level of a propeller rotation axis and the second holding arms join the central support at a second level of a propeller rotation axis, the first level and the second level being separated by at least 50% of the maximum thickness of a first holding arm, the thickness being measured along the span of the holding arm (or stator), without taking into account its ends.

[0048] In some cases, the first support arms join the central support at a first level of a propeller rotation axis and the second support arms join the central support at a second level of a propeller rotation axis, the first level and the second level being separated by at most three times the maximum length of a chord of a first support arm, the chord being between a leading edge and a corresponding trailing edge of said support arm.

[0049] In some cases, the first holding arms join the opening perimeter at a first level of a propeller rotation axis and the second holding arms join the central support at a second level of a propeller rotation axis, the first level and the second level being separated by at most three times the maximum length of a chord of a first holding arm, the chord being between a leading edge and a corresponding trailing edge of said holding arm.

[0050] In some cases, the first support arms cross the second support arms. Such a configuration is particularly rigid while allowing limited space requirements.

[0051] There Figure 3 represents a simplified view of an example of a ventilation device 30 comprising a propeller 310 whose motor 320 is carried by a support frame 300 according to this description. The propeller 310 has an axis of rotation 301 which may, for example, correspond to the axis 101 or 201 of the preceding Figures. The propeller can be placed either between the frame and the motor to be cooled. The frame can also be located between the propeller and the motor to be cooled. The combination of the aerodynamic function of the propeller with the aerodynamic shape of the studs according to this description makes it possible to obtain an improvement in the efficiency of the system as a whole. This efficiency is further improved by combining the aerodynamic capabilities of the propeller, the studs according to this description and an aerodynamic shape of the support arm.

[0052] There Figure 4 illustrates an example of a cooling module 40 of the thermal engine of a motor vehicle comprising a ventilation device according to this disclosure. In this case, the module comprises the elements shown in the Figure 3 , as well as a radiator 400 subjected to the flow generated by the propeller 310 and modified by the aerodynamic shape of the pads as described in this presentation. In this case, the propeller is placed between the radiator 400 and the frame 300, but the frame 300 could also be placed between the propeller and the radiator.

Claims

1. Support frame for a ventilation device for cooling a fluid passing through a cooling circuit of a motor vehicle, said frame comprising an opening defining an opening perimeter, the opening being intended to receive an impeller, and a central support positioned at the centre of said opening and shaped so as to receive a motor actuating said impeller so as to generate a ventilation flow, said central support being attached, through said opening, to the frame by at least six holding arms, at least three first holding arms being placed in a first plane or cone of revolution, characterized in that at least three second holding arms are placed in a second plane or cone of revolution that is different to the first plane or cone of revolution, the first holding arms each being separated from any second holding arm at the opening perimeter by a space covering at least a distance corresponding to a chord of said first holding arms.

2. Frame according to Claim 1, the first holding arms being placed in a first plane and the second holding arms being placed in a second plane parallel to the first plane.

3. Frame according to Claim 1, the first holding arms being placed in a first cone of revolution and the second holding arms being placed in a second cone of revolution that is different to the first cone of revolution.

4. Frame according to Claim 3, the first holding arms forming a first angle with a plane defined by the opening, the second holding arms forming a second angle with the plane defined by the opening, the first angle and the second angle having opposite signs.

5. Frame according to Claim 3, the first holding arms forming a first angle with a plane defined by the opening, the second holding arms forming a second angle with the plane defined by the opening, the first angle and the second angle having the same sign.

6. Frame according to any one of Claims 1 to 5, the first holding arms forming groups of first holding arms following one another along the opening perimeter, each group of first holding arms being separated from another group of first holding arms at least by a second holding arm or by a group of second holding arms.

7. Frame according to any one of the preceding claims, the opening having the shape of a ring, the ring comprising three complementary sectors, each complementary sector covering 120 degrees of the ring, each complementary sector comprising the same number of first and second holding arms.

8. Frame according to any one of the preceding claims, each holding arm being connected to the frame by a corresponding stud, said studs extending perpendicularly to the opening, some of said studs connected to the first holding arms having a first height perpendicular to the opening, starting from a plane comprising the opening, and some others of said studs connected to the second holding arms having a second height perpendicular to the opening, starting from the plane comprising the opening, the first height being different to the second height.

9. Ventilation device comprising an impeller, the motor of which is borne by the support frame according to one of the preceding claims.

10. Cooling module for the combustion engine of a motor vehicle comprising the ventilation device according to Claim 9.