Motor-fan unit with axial air inlet and air outlet.

Abstract

Title of the invention: Motor-fan unit with axial air inlet and air outlet. The present invention relates to a motor-fan assembly (2) comprising at least one guide element and a propeller (6) comprising a plurality of blades (22), the propeller (6) being configured to force an axial inlet, along an axis of rotation (A), of an airflow into the housing (4), the guide element being configured to direct the airflow towards an air outlet (12) parallel to the axis of rotation (A), characterized in that at least one blade (22) of the propeller (6) comprises an underside (34) extending between the leading edge (24) and the trailing edge (26) of a blade (22), said underside having a curvature with a proximal portion closest to the leading edge (24) extending opposite an upper surface of the adjacent blade and at least one other portion extending opposite the support (30) and / or opposite a blade of the guiding element. (Figure 7)

Description

Title of the invention: Motor-fan unit with axial air inlet and air outlet.

[0001] The present invention relates to the field of motor-fan assemblies, particularly those intended for use in motor vehicles. More specifically, the present invention relates to the circulation of an airflow within such a motor-fan assembly.

[0002] Vehicles, and in particular motor vehicles, typically include a ventilation, heating, and / or air conditioning system designed for the thermal treatment of an airflow intended, for example, to be sent into the passenger compartment of that vehicle. These ventilation, heating, and / or air conditioning systems include at least one housing containing at least one heat exchanger and at least one fan motor assembly. Within these systems, the fan motor assembly forces the airflow through the heat exchanger to thermally treat the airflow before it is sent into the passenger compartment of the vehicle.

[0003] The fan motor assembly comprises at least one fan blade housed in a casing, this fan blade being driven in rotation, for example, by a drive motor which may also be housed in the casing. Some fan motor assemblies currently implemented include an axial air inlet, that is to say, an opening which allows airflow to enter the fan motor assembly in a direction parallel, or substantially parallel, to an axis of rotation of the fan blade of this fan motor assembly, and an axially directed air outlet.

[0004] These fan motor assemblies are described in particular in application WO2023006764. They comprise, in particular, a housing containing a radial impeller, the impeller drive motor, and a guide element configured to direct the airflow exiting the impeller towards the axial air outlet. A "radial impeller" is understood to be an impeller in which the airflow enters in a first direction, in this case parallel to the axis of rotation of the impeller, and exits in a second transverse direction, essentially perpendicular to the axis of rotation of the impeller. The guide element is formed both by the inner face of the housing walls, in the direction towards which the airflow leaves the radial impeller and which functions to direct the airflow to an axial flow direction, and by fixed guide blades having curvatures suitable for recentering the airflow towards the axial air outlet.Such motor-fan assemblies have the advantage of having a limited radial footprint, since the air is straightened within the housing, without the need for flexible connections protruding from the housing to guide the air towards the component to be supplied with fresh air. However, it should be noted that the direction of the airflow exiting the radial propeller is substantially perpendicular to the inner face of the case and that vortices are then generated which has the effect of creating pressure loss.

[0005] The present invention falls within this context and aims to resolve at least some of the drawbacks of the prior art by proposing a motor-fan unit whose size is reduced radially while limiting pressure losses.

[0006] Thus, the present invention relates to a motor-fan assembly comprising at least one housing defining an internal volume between an air inlet and an air outlet, the motor-fan assembly comprising at least one propeller housed within the internal volume of the housing and a guide element, the propeller being configured to be driven in rotation about an axis of rotation and to force an axial inlet, along the axis of rotation, of an airflow into the housing through the air inlet, the propeller comprising a support and a plurality of blades distributed around the axis of rotation and extending radially from a leading edge to a trailing edge, the leading edge and trailing edge of each blade projecting from said support, the guide element being formed of at least a plurality of blades arranged circumferentially around the axis of rotation between the propeller and the air outlet, said blades being configured to direct axially,Along the axis of rotation, the airflow is directed towards the air outlet.

[0007] According to the invention, at least one propeller blade comprises an intrados extending between the leading edge and the trailing edge of a blade and along which the airflow passing between two adjacent blades is intended to flow mainly, said intrados having a curvature with a proximal portion closest to the leading edge extending opposite an extrados of the adjacent blade to define a substantially radial airflow circulation duct and at least one other portion, opposite the proximal portion, which is folded down to extend opposite the support and / or opposite a blade of the guide member to axially delimit said airflow circulation duct.

[0008] The propeller forms the part of the motor-fan assembly designed to force the circulation of airflow through the motor-fan assembly. To this end, the propeller comprises a plurality of blades driven in rotation about the propeller's axis of rotation. These blades extend between a leading edge and a trailing edge, the leading edge being the part of a blade that is closest to the axis of rotation and is initially in contact with the airflow. Thus, a portion of the airflow passing through the motor-fan assembly first comes into contact with the leading edge of a blade and then flows, in a duct defined between two adjacent blades, towards the trailing edge of said blade, notably by flowing along the underside of one of the adjacent blades. The intrados is the face of the blade oriented in the direction of the propeller's rotation, the extrados being the face opposite the intrados of said blade, so that The intrados is the face of a blade along which mainly flows the part of the airflow circulating in the duct delimited in particular by this intrados.

[0009] Functionally, the proximal portion of the lower surface, that is, the portion closest to the leading edge of a blade, is configured to direct the airflow essentially radially with respect to the propeller's axis of rotation, and a portion of the lower surface opposite the proximal portion is configured to direct the airflow essentially axially with respect to the propeller's axis of rotation. The curvature of the propeller blades helps to straighten at least part of the airflow, shifting it from a radial flow direction at the leading edge of a blade to a predominantly axial flow direction at the trailing edge of said blade. It should be noted that the axial and radial directions are considered with respect to the propeller's axis of rotation.Thus, an axial direction corresponds to a direction parallel to the axis of rotation of the propeller, and a radial direction corresponds to a direction perpendicular to the axis of rotation.

[0010] It should be noted that at the trailing edge of each propeller blade, the axial component of the airflow is greater than the radial component of said flow. In other words, the airflow at the trailing edge of the blades flows primarily in an axial direction. By way of example, it can be considered that at least 60% of the airflow circulating in a duct between two adjacent blades is straightened parallel to the axis of rotation of the propeller when this airflow reaches the trailing edge of the blades.

[0011] The configuration of at least one blade, as described above, allows for the creation of at least one hybrid blade, namely a blade that both radially directs the airflow and axially straightens it. This configuration is particularly advantageous in the context of a motor-fan assembly with an axial air inlet and an axial air outlet, since the shape of the blades allows for at least partial straightening of the airflow direction within the housing and gives it an axial component. More specifically, it is the combination of the blade shape and the housing shape, which defines the propeller housing, that contributes to axially straightening the airflow inside the housing.Advantageously, it is no longer, as in the prior art, solely the wall of the casing that has the responsibility of straightening the airflow coming substantially radially against it to direct it towards the blades of the guide element, which improves the efficiency of this straightening, by avoiding the appearance of significant vortices at the contact of the airflow with the wall of the casing.

[0012] Furthermore, the blades of the guide element are fixed relative to the housing and are configured, in particular by a variation in their curvature between their leading edge and their trailing edge, to recenter the airflow during its movement axial towards the axial air outlet, that is to say to direct it towards the axis of rotation of the radial propeller.

[0013] According to one feature of the invention, at least one blade is configured such that its lower surface has a distal portion, opposite said proximal portion, the curvature of which is such that the lower surface extends radially beyond the support in relation to a blade of the guide element. In other words, according to one feature of the invention, the curvature of at least one blade is variable, with the curvature in successive planes of cut parallel to the axis of rotation of the propeller increasing as one approaches the trailing edge, and the center of curvature moving axially toward the air outlet as one approaches the trailing edge. The curvature of a distal portion of the blade is greater in the portion extending radially beyond the support than in the portion supported by the support.

[0014] According to a feature of the invention, the trailing edge of at least one propeller blade extends radially beyond the support and has an inclination with respect to the axis of rotation of the propeller so as to be opposite at least one blade of the guide member.

[0015] According to one feature of the invention, at least one blade is attached to the support at the level of a first edge, the trailing edge of at least one blade having an end attached to the support and an opposite end which forms a free end, at the junction of this trailing edge and a second edge.

[0016] According to a feature of the invention, said free end of the trailing edge is the end furthest from the axis of rotation of the propeller and it extends to a distance from a wall defining the first part of the housing which is less than 6 mm. This distance is measured perpendicular to the axis of rotation.

[0017] According to a feature of the invention, said free end of the trailing edge is the end furthest from the axis of rotation of the propeller and it extends to a distance from a wall defining the first part of the housing which is less than 5% of the distance between the axis of rotation and said wall, said distance being measured perpendicular to the axis of rotation of the propeller.

[0018] The fact that the trailing edge extends beyond the support allows the airflow reaching the trailing edge, and which is therefore oriented at least partly axially by the specific curvature of the distal portion of the lower surface of the mixed blade as previously described, to escape axially once it has passed the radial end of the support, so as to be directed towards the blades of the guide element. Thus, the support does not create an obstacle to the flow of air reaching the trailing edge, in a direction parallel to the axis of rotation of the propeller.

[0019] According to one feature of the invention, the housing is formed of at least a first part housing the propeller and a second part within which the blades of the guide member extend, the first part of the housing extending between a first end and a second end, the first end being closer to the air inlet than the second end, the first part of the housing having a shape substantially complementary to the shape of said propeller blades from the first end to the second end.

[0020] The complementarity of shapes between the first part of the housing and the shape of a propeller blade is appreciated in particular at the level of an edge of this blade connecting the leading edge to the trailing edge, with a distance which remains constant between the wall forming the first part of the housing and this edge.

[0021] Furthermore, "a substantially complementary shape" means that at least 90% of the area between the first end and the second end has a shape complementary to the shape of the blades. Indeed, at the first and second ends, means can be implemented, including fastening means, to ensure the assembly of the motor-fan unit, as at the second end of the first part of the housing.

[0022] According to a feature of the invention, the support extends so that an axial end of this support closest to the blades of the guide member is substantially at the level of a junction plane between the first part of the housing and the second part of the housing.

[0023] According to one feature of the invention, the leading edge of a blade extends along a first principal extension direction and the trailing edge of said blade extends along a second principal extension direction, the first principal extension direction and the second principal extension direction being secant to the axis of rotation.

[0024] According to a feature of the invention, an angle between the second main extension direction and the axis of rotation of the propeller is greater than an angle between the first main extension direction and the axis of rotation of the propeller.

[0025] The first main extension direction forms an angle with the axis of rotation of between 20 and 60 degrees. Furthermore, the second main extension direction forms an angle with the axis of rotation of between 60 and 90 degrees. The second main extension direction tends to approach an angle of 80° so as to be able to direct the airflow towards the blades of the guide element.

[0026] According to a feature of the invention, the trailing edge of a blade is angularly offset relative to the leading edge of said blade according to the direction of rotation of the propeller.

[0027] According to a feature of the invention, the leading edge of the blades extends into a space delimited by a projection of the air inlet parallel to the axis of rotation of the propeller.

[0028] According to one feature of the invention, the propeller blades are distributed irregularly around the axis of rotation of the propeller.

[0029] According to one feature of the invention, a first angular separation measured with respect to the axis of rotation between two consecutive blades is different from a second angular separation measured with respect to said axis of rotation between two other consecutive blades. The angular separations between two consecutive blades are measured here at the leading edges of said blades.

[0030] According to a feature of the invention, an angular separation measured with respect to the axis of rotation between two consecutive blades is different from an angular dimension measured with respect to said axis of rotation between two consecutive blades.

[0031] It is noteworthy that in each of these two configurations, the asymmetry created by the different angular spacings has the effect of limiting the appearance of recurring noises at a given frequency, which can create acoustic discomfort for the vehicle user.

[0032] According to one feature of the invention, the distance, or angular separation, between a first edge of two adjacent blades is variable from one pair of adjacent blades to another pair of adjacent blades.

[0033] According to one feature of the invention, at least one of said blades of the guide member extends along a principal elongation direction between a first edge and a second edge, the second edge being offset relative to the first edge, both axially and angularly in the direction of rotation of the propeller. The first edge of a blade forms the part of said blade closest to the propeller and the second edge of a blade forms the part of said blade furthest from the propeller.

[0034] According to one feature of the invention, each of the blades of the guide element extends along a principal elongation direction between a first edge and a second edge, the second edge of each of the blades of the guide element being offset from the corresponding first edge of the blade, both axially and angularly in the direction of rotation of the propeller.

[0035] According to one feature of the invention, each of the blades of the guide element has a progressive curvature, with the center of curvature tending to approach the axis of rotation as one approaches the second edge, near the air outlet. In this way, the airflow tends to be recentered towards the axis of rotation as one approaches the outlet.

[0036] According to one feature of the invention, the housing helps to define an annular conduit extending parallel to the axis of rotation of the propeller, at least one blade of the guiding element extending across the annular duct, being fixed to an inner peripheral edge of the annular duct and to an outer peripheral edge of said annular duct, the inner peripheral edge being opposite the outer peripheral edge. The inner peripheral edge helps to delimit a zone in which the propeller drive motor is located.

[0037] According to one feature of the invention, the distance between a blade and the trailing edge of a blade opposite said blade increases as the distance from the axis of rotation increases. The distance between a blade and a trailing edge of a blade is measured parallel to the axis of rotation of the propeller when this blade is angled so as to axially overlap this blade. The portion of the blade of the guide element that is furthest from the axis of rotation of the propeller is farther from the trailing edge of the blade opposite said blade than is the portion of the blade closest to the axis of rotation.In this way, a compromise is made between having the trailing edges of the blades as close as possible to the blades and / or the inner face of the housing wall, for the efficiency of guiding the airflow by limiting pressure losses, but which are nevertheless far enough away from the guide blades to avoid strong compression of the airflow when a rotating blade passes in front of a fixed blade, this compression generating noise likely to disturb the vehicle user.

[0038] According to a feature of the invention, a straight line perpendicular to the axis of rotation and passing through the leading edge of a blade at the level of a junction between said leading edge and the support and a straight line perpendicular to the axis of rotation and passing through the trailing edge of said blade at the level of the junction between said trailing edge and the support form a first phase angle of between 45° and 65°.

[0039] According to a feature of the invention, a straight line perpendicular to the axis of rotation and passing through one end of the distal leading edge of the support and a straight line perpendicular to the axis of rotation and passing through one end of the distal trailing edge of the support form a second phase angle between 30° and 55°.

[0040] According to a feature of the invention, the leading edge of a blade has a first axis extending parallel to the axis of rotation and passing through said leading edge at the junction between the leading edge and the support, an entry angle which can be between 30° and 55°, preferably between 35° and 50°, more preferably between 40° and 45°.

[0041] According to one feature of the invention, the trailing edge of a blade has a second axis A2 extending perpendicularly to the axis of rotation A and passing through the trailing edge 26 at the junction between the trailing edge 26 and the support 30, forming an exit angle 104 which can be between -15° and 15°, preferably between 5° and 15°, more preferably between 10° and 15°. It should be noted that a A negative angular value represents a trailing edge that tends to move axially closer to a blade of the guide element, and a positive angular value represents a trailing edge that tends to move axially away from a blade of the guide element.

[0042] Other features, details and advantages of the invention will become clearer upon reading the following description on the one hand, and several exemplary embodiments given by way of illustration and not limitation with reference to the accompanying schematic drawings on the other hand, in which:

[0043] [Fig-1] schematically represents a general view of a motor-fan assembly in accordance with the present invention, the figure showing a propeller and a housing of the motor-fan unit as well as the axial inlet of the airflow;

[0044] [Fig.2] schematically represents a propeller of the motor-fan assembly forcing the circulation of an airflow within the casing and one of the parts of the casing participating in forming a guide element according to the present invention, said part of the casing being notched to make visible a blade guide element configured to direct the airflow towards an axial outlet not visible here;

[0045] [Fig.3] schematically represents a cross-sectional view of the helix visible on the [Fig.2] and highlighting the inclination of a leading edge and a trailing edge of a propeller blade with respect to an axis of rotation of said propeller;

[0046] [Fig.4] schematically represents a cross-sectional view of the propeller, with a perspective allowing to account in particular for the curvature of the propeller blades;

[0047] [Fig.5] schematically represents a top view of the propeller visible on the [Fig.2] and highlighting an irregular distribution of the propeller blades around the axis of rotation of the propeller;

[0048] [Fig.6] schematically represents a top view of the visible part of the housing on [Fig.2] highlighting an irregular distribution of blades attached to the second part of the housing and partly forming the guiding element;

[0049] [Fig.7] schematically represents a cross-sectional view of the motor-fan assembly visible on [Fig.1] and highlighting the circulation of an airflow within the motor-fan group;

[0050] [Fig.8] schematically represents a detail of a cross-sectional view of the motor- fan visible on [Fig.l] and highlighting a distance between a blade and a blade which increases as one moves away from the axis of rotation of the propeller;

[0051] [Fig.9] schematically represents a two-dimensional view of a blade putting highlighting the inclination of the leading edge of said blade relative to the axis of rotation of the propeller and the inclination of the trailing edge of said blade relative to the axis of rotation of the propeller.

[0052] The features, variants, and different embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features, described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0053] In the following description, the terms "longitudinal," "transverse," and "vertical" refer to the orientation of a thermal regulation system according to the invention. A longitudinal direction corresponds to an axis of rotation of a propeller equipping the motor-fan assembly, this longitudinal direction being parallel to a longitudinal axis L of a frame of reference L, V, T illustrated in the figures. A transverse direction corresponds to a direction extending perpendicularly to the axis of rotation of the propeller, this transverse direction being parallel to a transverse axis T of the frame of reference L, V, T, and perpendicular to the longitudinal axis L. Finally, a vertical direction corresponds to a vertical axis V of this frame of reference L, V, T, this vertical axis V being perpendicular to the longitudinal axis L and the transverse axis T.

[0054] Figure 1 represents a motor-fan assembly 2 according to the present invention. The motor-fan assembly 2 comprises a housing 4 delimiting an internal volume in which are housed at least one propeller 6 configured to force the circulation of an airflow through the housing 4 and a guide member which will be described in more detail in the following description.

[0055] The motor-fan assembly 2 is intended, in particular, to be part of a ventilation, heating and / or air conditioning system integrated into a motor vehicle so as to thermally treat an airflow before it is sent, for example, into the passenger compartment of the motor vehicle. This airflow is then used to cool or heat the passenger compartment of the vehicle.

[0056] As seen in [Fig. 1], the housing 4 is formed of at least two parts joined together in pairs by fastening means 8, these parts defining the internal volume of the housing 4 which extends between an air inlet 10 and an air outlet 12, as seen in [Fig. 6].

[0057] The fastening means 8 may consist, by way of illustrative and non-limiting example of the invention, of screwing means, with fastening tabs which are formed respectively on one of the two parts of the housing 4 to be joined, these fastening tabs each having an orifice with at least one orifice which is tapped and is suitable for cooperating with a screw of complementary shape. Alternatively, the fastening means 8 can be formed, for example, of an elastically deformable tab made on a part of the housing 4 and fitting into a notch made on an adjacent part of the housing 4.

[0058] In the illustrated example, the housing 4 comprises a first part 14 forming at least one part of the guide member and comprising an opening 16 participating in forming the air inlet 10, a second cylindrical part 18 forming at least another part of the guide member, and a third part 20 participating in forming the air outlet 12. It is understood that the housing could comprise a different number of parts, and for example only two parts with the air outlet 12 which is formed at one end of the second part 18 opposite to the first part.

[0059] Each of the parts 14, 18, 20 is secured to at least one other of said parts 14, 18, 20 by the fastening means 8 previously mentioned. It should be noted that the fastening of the parts 14, 18, 20 to each other is airtight, so that the airflow circulating in the internal volume is able to enter and exit the housing 4 strictly through the air inlet 10 and the air outlet 12 respectively.

[0060] The circulation of the airflow within the housing 4 is forced from the air inlet 10 to the air outlet 12 by the propeller 6. This propeller 6 is, during the operation of the motor-fan unit 2, capable of being driven in rotation in a direction of rotation S around an axis of rotation A. The axis of rotation A extends, in the embodiment shown, along a direction substantially parallel to the axis L.

[0061] The rotation of the propeller 6 is ensured by a drive element, not shown here, housed in the internal volume of the casing 4. More specifically, in the embodiment shown and without limiting the invention, the drive element is an electric motor comprising in particular a rotor attached to the propeller 6 and a stator attached to the second part 18 of the casing 4.

[0062] It is noteworthy in [Fig. 1] that the first part 14, the second part 18 and the third part 20 of the housing are assembled relative to each other in a stacking direction parallel to the axis L, this stacking direction of parts 14, 18, 20 of the housing 4 being parallel to the axis of rotation A of the propeller 6. Such a stacking of parts 14, 18, 20 of the housing 4 makes it possible to limit the axial size of the motor-fan assembly 2. The air inlet 10 extends radially around the axis of rotation A, so that the airflow is made to enter the housing 4 in an axial direction, that is to say in a direction parallel to the axis of rotation A and therefore to the stacking direction of parts 14, 18, 20 of the housing 4.

[0063] Figure 2 illustrates an isolated view of the propeller 6 and the second cylindrical portion 18 of the housing 4. It should be noted that in this Figure 2, a portion of the second portion 18 has was removed to reveal blades 21 attached to the second part 18 of the housing 4 and forming part of the guide element.

[0064] The propeller 6 is formed of a plurality of blades 22 extending radially with respect to the axis of rotation A between a leading edge 24 and a trailing edge 26. The leading edge 24 and the trailing edge 26 of a blade 22 are connected to each other by a first edge 28, integral with a support 30 of the propeller 6 and turned towards the air outlet 12, and by a second edge 32, opposite to the first edge 28 and turned towards the air inlet 10.

[0065] The support 30 extends radially from the axis of rotation A of the propeller 6. When the propeller 6 is driven into rotation by the driving member, both the support 30 and the blades 22 are driven into rotation.

[0066] The leading edge 24 of the blades 22 extends from the support 30 to an annular band 38 which, as seen in [Fig.3], is located near the opening 16 made in the first part 14 of the housing 4. The annular band 38 is attached to the support 30 by means of the blades 22. This annular band 38 provides the propeller 6 with sufficient rigidity to prevent deformation of the blades 22 when the propeller 6 is rotated.

[0067] The leading edge 24 of the blades 22 extends within a space delimited by a projection, parallel to the axis of rotation A of the propeller 6, of the air inlet 10 and more particularly of the opening 16 defining this air inlet. This space, in which all the leading edges are contained, can also be defined by the projection along this same longitudinal direction of the annular band 38, integral with the second edge 32 of the blades 22 at one end of the leading edge 24 of these blades 22.

[0068] The opposite end of the leading edge 24, that is to say the end of the leading edge 24 attached to the support 30, is closer to the axis of rotation A than the end of the leading edge 24 located near the annular band 38. Thus, the leading edge 24 of the blades 22 extends in a projection of the air inlet 10 from the annular band 38 towards the support 30, in the direction of the axis of rotation A.

[0069] More specifically, the area in which the leading edges 24 of the blades 22 extend, from the annular band 38 towards the axis of rotation A, corresponds, in projection onto a plane perpendicular to the axis of rotation A, to approximately 50% of the space delimited by the projection of the air inlet 10 onto that same plane. This characteristic allows the blades 22 of the propeller 6, and more specifically the leading edge 24 of said blades 22, to force the radial circulation of air by centrifugal force with less pressure loss, since the airflow arriving through the air inlet 10 quickly encounters a leading edge of a blade.

[0070] The blades 22 are also inclined with respect to the direction of rotation S of the propeller 6. This inclination of the blades 22 is remarkable by a part of the first edge 28 of a blade 22 closest to the leading edge 24 which has an angular offset, here positive, with respect to a part of said first edge 28 closest to the trailing edge 26. In other words, when the propeller rotates, the part close to the leading edge arrives before the part close to the trailing edge.

[0071] The blades 22 comprise a first face 34 delimited between the leading edge 24, the trailing edge 26, the first edge 28, and the second edge 32. This first face 34 forms an intrados, that is, the face of a blade 22 designed to direct the airflow entering through the air inlet 10 towards the air outlet 12. Opposite the first face 34, the blades 22 comprise a second face 36 forming an extrados. The inclination of the blades 22 is such that at least a portion of the intrados of the blades 22 is aligned with at least one blade 21 of the guide member.

[0072] Between the first face 34 of a blade 22 and the second face 36 of an adjacent blade 22, the propeller 6 defines an airflow channel 40. The airflow channel 40 allows the propeller 6, initially, to direct the airflow essentially radially with respect to the axis of rotation A, that is, towards a wall 76, visible in [Fig. 6], of the first part 14 forming part of the guide element, and then, subsequently, to direct the airflow essentially axially with respect to the axis of rotation A, that is, mainly towards the blades 21 of the guide element. It should be noted that the wall 76 of the first part 14 will be described in more detail in connection with [Fig. 6].

[0073] This change in the direction of the airflow within the circulation channel 40 is achieved on the one hand by the combination of shapes between the propeller blades and the housing, which forms a conduit opening opposite the guide blades, with in particular the trailing edge 26 of the blades 22 which extends radially beyond the support 30, and on the other hand by the shape specific to the propeller 6 according to the invention, with in particular a specific curvature of the blades 22.

[0074] Indeed, the second edge 32 extends radially from the axis of rotation A over a greater distance than the radial distance of the first edge 28 from the axis of rotation A. As can be seen in particular in [Fig. 3], the trailing edge end 26 furthest radially from the axis of rotation A, that is, the trailing edge end connected to the second edge 32, is directly opposite the blades 21 of the guide element. Thus, the airflow reaching the trailing edge 26 of a blade 22 is not blocked by the support 30 and can flow axially towards the blades 21 and then towards the air outlet 12.

[0075] Furthermore, the blades 22 have a curvature which modifies the orientation of the first face 34, i.e. the intrados, between a part of the first face 34 the closer to the leading edge 24 and a part of said first face 34 closest to the trailing edge 26.

[0076] Extending radially from the axis of rotation A to the radial end of the support 30, the lower surface of a blade 22 is initially substantially flat and oriented towards the upper surface of an adjacent blade 22, then it forms a curvature to fold down towards the support 30 so that in this curved portion, a base of the lower surface, directly in the vicinity of the support 30, remains opposite the upper surface of the adjacent blade while an upper portion, extending the base, is curved towards the upper surface of the adjacent blade 22, coming into contact with the support 30, and where appropriate opposite a blade 21 if this part of the lower surface continues radially beyond the support.Such a curvature of the blades 22 makes it possible to radially delimit the circulation channel 40 when the lower surface of a blade 22 is entirely opposite the upper surface of an adjacent blade 22 and to axially delimit the circulation channel 40 when part of the lower surface of a blade 22 is opposite the support 30 and / or a blade 21. Thus, the airflow circulating in the circulation channel 40 can circulate freely radially at the beginning of the circulation channel 40 before being forced down by the lower surface of a blade 22 as the airflow approaches the blades.

[0077] More specifically, the part of the lower surface closest to the leading edge 24, or in other words the lower surface of a proximal part 224 of the blade 22, is substantially straight and turned towards the upper surface of an adjacent blade 22, to channel the airflow essentially radially, and the part of the lower surface closest to the trailing edge 26, or in other words the lower surface of a distal part 226 of the blade 22, is curved and turned towards the support 30, to direct the airflow towards this guiding element. This specific curvature will be detailed in particular with reference to [Fig.4] whose cross-sectional view makes it easier to identify a proximal part 224 of a first blade 221, a distal part 226 of another blade 223, as well as a central part 225 of another blade 222.

[0078] As mentioned, the blades 22 of the propeller 6 can also be configured so that at least a portion of the lower surface is oriented towards at least one blade 21 of the guide element. Thus, the trailing edge 26 of at least one of said blades 22 is inclined with respect to the axis of rotation A of the propeller 6 so as to extend radially outward from the support, so that the trailing edge of a blade and the distal portion 226 of the blade 22 which carries this trailing edge are opposite the blades 21 of the guide element during the rotation of the propeller.

[0079] It follows from this specific curvature of the blades 22 that the airflow circulating within a circulation channel 40 is straightened, at the periphery of the propeller, to take on mainly an axial component in the direction of the air outlet 12, this straightening of the airflow being achieved in particular by the specific configuration blades and not only the shape of the walls of the housing surrounding this propeller. Indeed, the airflow circulating in a circulation channel 40 flows in a radial direction with respect to the axis of rotation A, constrained between the support 30, the part of the first face 34 of a blade 22 closest to the leading edge 24, the second face 36 and the wall 76 of the first part 14 of the housing 4. When the airflow reaches the part of the first face 34 of said blade 22 closest to the trailing edge 26, the airflow follows the specific curvature of this first face 34 closest to the trailing edge 26 and is straightened axially towards the blades 21 of the guide member and therefore towards the air outlet 12.

[0080] As mentioned previously, the guide element is formed by the wall 76 and the blades 21. This guide element is configured to direct the airflow towards the air outlet 12 along a main air outlet direction extending parallel to the axis of rotation A of the propeller 6. The motor-fan assembly 2 is then able to draw the airflow into the housing 4 in an axial direction and to draw said airflow out of the housing 4 in the same direction.

[0081] The blades 21 of the guide element are arranged between the air outlet 12 and the propeller 6. In the embodiment shown, the blades 21 of the guide element extend along a main elongation direction between a first edge 42 and a second edge 44, these edges 42, 44 being connected to each other by sides 48, 52. The blades 21 are integral with a first portion 46 of the second part 18 of the housing 14 by a first side 48 and with a second portion 50 of the second part 18 by a second side 52. Thus, the blades 21 and the second part 18 of the housing 4 form a single unit.

[0082] The first edge 42 of the blades 21 is axially offset relative to the second edge 44. More specifically, the first edge 42 is closer to the propeller 6 than the second edge 44. Furthermore, the first edge 42 exhibits a negative angular offset relative to the second edge 44 of the same blade 21, considering the direction of rotation of the propeller. In other words, since the blades 21 are fixed relative to the rotating propeller, the trailing edges of the blades first assume an angular position in which these trailing edges are aligned with the first edge 42 of the blades, and then an angular position in which they are aligned with the second edge of the same blades.

[0083] The blades 21 are arranged in a partially overlapping manner, with a second edge 44 of a blade 21 being axially covered by a portion of the preceding blade when considering the direction of rotation of the rotor, such that a flow duct 54 for the airflow is formed between two adjacent blades 21. This flow duct 54 is configured, in particular due to the curvature of the blades, as described in the patent application WO2023006764. by the plaintiff, to correct the direction of the airflow again and in particular to recenter the airflow, by guiding it towards the axis of rotation A.

[0084] Fig. 3 illustrates a cross-sectional view of the propeller 6 at the level of a blade 22, highlighting, in particular, different inclinations between the leading edge 24 and the trailing edge 26 of said blade 22 with respect to the axis of rotation A.

[0085] As can be seen in [Fig.3], the leading edge 24 of a blade 22 extends mainly along a first principal extension direction, schematically represented by a first straight line 56. It is also visible in [Fig.3] that the trailing edge 26 of a blade 22 extends mainly along a second principal extension direction, schematically represented by a second straight line 58.

[0086] The first main extension direction, represented by the first line 56, is secant to the axis of rotation A. Indeed, the first line 56 is inclined with respect to the axis of rotation A, this inclination resulting from the fact that one end of the leading edge 24, which is closest to the support 30, is closer to the axis of rotation A than an opposite end of said leading edge 24, that is to say the end of the leading edge 24 closest to the annular band 38. Thus, the first main extension direction forms a first angle α with the axis of rotation A of between 20 and 60 degrees. This inclination allows both not to obstruct the opening of the air inlet 10, by ensuring that the leading edge edges are hidden by the annular band 38, and to cover a large area at the support 30 with the blades to efficiently guide the airflow around the periphery of the propeller.Thus, the propeller 6 is, as previously stated, capable of forcing the circulation of a large volume of air in the circulation channels 40 and therefore through the housing 4.

[0087] Furthermore, the second main extension direction, represented by the second line 58, is secant to the axis of rotation A. The second line 58 is inclined with respect to the axis of rotation, this inclination resulting from the fact that one end of the trailing edge 26, which is closest to the support 30, is closer to the axis of rotation A than an opposite end of said trailing edge 26. Thus, the second main extension direction forms a second angle [3] with the axis of rotation A of between 60 and 90 degrees.

[0088] It should be noted that the first angle a is different from the second angle [3. More specifically, the value of the first angle a is less than the value of the second angle [3. This angular difference with respect to the axis of rotation A between the first main extension direction and the second main extension direction results from the curvature of the blades 22 which tends to straighten the airflow axially.

[0089] Moreover, the closer the value of the second angle [3] is to 90°, that is, the closer the inclination of the trailing edge 26 is to perpendicularity with respect to the axis of rotation A, and the more the airflow is axially straightened towards the air outlet 12. It results from these two different inclinations that the first principal extension direction forms a third angle y with the second principal extension direction between 30 and 45 degrees.

[0090] It is particularly noticeable in [Fig. 3] that the propeller blades 22 extend radially with respect to the propeller's axis of rotation such that a distal portion of each blade, bearing the trailing edge 26, extends radially beyond the support. In particular, the trailing edge 26 extends from the support and has, opposite it, a free end 27, said free end 27 extending radially outward from the support. The inclination of the trailing edge 26 and the fact that it extends outward from the support 30 carrying the blades allows the airflow to be directed directly toward the blades of the guide element. As mentioned, this is made possible, in particular, by the curvature of each of the propeller blades 22.

[0091] Figure 4 makes this blade curvature particularly visible, notably by representing adjacent blades along a cutting plane that does not pass through the axis of rotation, unlike the cutting plane of Figure 3. The concepts of curvature that will be discussed with reference to Figure 4 are to be considered in this cutting plane or an equivalent cutting plane parallel to the axis of rotation.

[0092] A first blade, here referred to as 221 for ease of reading, is cut at the junction between the blade and the annular band 38, in a portion close to the leading edge of the blade, so that [Fig. 4] shows a proximal portion 224 of this blade. In this proximal portion 224, the blade has a particular initial curvature with a substantially straight shape, or a large radius of curvature. Thus, the proximal portion of the lower surface, or first face 34, is substantially parallel to the axis of rotation A from the first edge 28 to the second edge 32. As mentioned previously, this proximal portion of the lower surface is turned towards the upper surface of the adjacent blade to define, together with the support and the inner face of the housing (not shown here), the airflow path.In this section, the aim is to guide the air primarily radially, or at the very least in a transverse direction perpendicular to the axis of rotation, towards the trailing edge of the blades.

[0093] A second blade, here referenced as 222 for ease of reading and corresponding to the blade directly adjacent to the first blade and offset angularly in a positive direction relative to the first blade, is cut at a central portion 225 of the blade, between its proximal portion 224 and its distal portion 226, which will be described below. A curvature is imparted to the second blade at this central portion 225 so that the second edge 32, which is free because it is not engaged with the annular band at the junction between the blade and the annular band 38, tends to move closer together. of the adjacent blade opposite the intrados, or first face 34. In this central portion 225, the blade has a particular intermediate curvature with a substantially straight shape at the base of the blade on the support side 30 and a part which extends it towards the second edge 32 which is curved with a radius of curvature which is less than the radius of curvature of the proximal portion 224 visible here for the first blade 221.

[0094] A third blade, here referenced as 223 for ease of reading, is cut at the junction between the trailing edge and the support 30, so that [Fig. 4] shows a distal portion 226 of the blade carrying the trailing edge. In this distal portion 226, the blade has a particular final curvature with a small radius arc shape. Thus, the distal portion 226 of the lower surface, or first face 34, is substantially perpendicular to the axis of rotation A at the junction with the second edge 32. The airflow is therefore delimited, opposite the duct, not by the inner face of a part of the housing, but by the lower surface. In this distal portion 226, the aim is to guide the air primarily axially, parallel to the axis of rotation, towards the guide element.

[0095] It should be noted that the curvature of the blades can continue beyond the cross-sectional plane illustrated here for the third blade, and that, in particular, the curvature of the distal portion of the blade can be greater in the portion extending radially beyond the support than in the portion supported by the support. In this way, the axial straightening of the airflow is further accentuated in a region where the lower surface of the blade is directly opposite the blades of the guide element.

[0096] These successive curvatures of a blade as it approaches a trailing edge contribute to forming mixed blades, whose function is both to generate radial circulation when the airflow encounters the blades, so as to efficiently evacuate it from the inlet portion of the propeller, and to subsequently generate axial circulation to facilitate its guidance towards the guide element designed to recenter it towards the axial outlet. This transition from an essentially radial circulation to an essentially axial circulation occurs by following the evolving profile of the lower surface of the mixed blade, which limits the pressure losses that could be observed if vortices appeared at the change in direction of the airflow. The evolving profile of the mixed blade allowing this transition without pressure loss is evident in this [Fig.4], with the radius of curvature of the blade, if we consider successive cutting planes from the leading edge to the trailing edge and which are parallel to each other and to a plane including the axis of rotation, which moves progressively towards the support and the axial outlet of the motor-fan assembly. .

[0097] In other words, in the propeller of the motor-fan assembly of the invention, each blade is a hybrid blade which, in its distal portion, ensures primarily radial circulation and, in its proximal portion, primarily axial circulation, thus straightening the airflow. It should be noted that the axial straightening of the airflow is not achieved solely by the blades but also by the inner face of the housing, which follows the curvature of the blades in a complementary manner. However, unlike the prior art, the axial straightening is not primarily achieved by the housing, and in this way, the airflow is better guided and pressure losses due to this change of direction are limited, as the transition from radial to axial circulation achieved by the blades is gradual.

[0098] It should be noted that this specific curvature of the blades 22 is remarkable at two levels on the [Fig.5] which will be described in more detail in the description that follows. Indeed, [Fig. 5] shows that the blades 22 are out of phase, meaning they are inclined relative to a general radial orientation, with a point on the leading edge and a point on the trailing edge not radially aligned, and that this phase shift differs depending on whether one considers points on the leading and trailing edges at the junction with the support 30 or at the junction with the annular band 38. A first phase shift angle 96 and a second phase shift angle 98 can thus be identified. It should also be noted that in the embodiment shown, each blade 22 is identical to the others, meaning that each blade 22 is superimposable on any of the other blades 22.

[0099] The first phase angle 96 is formed between, on the one hand, a straight line perpendicular to the axis of rotation A and passing through both this axis of rotation A and the leading edge 24 of a blade 22 at the level of the junction between said leading edge 24 and the support 30 and, on the other hand, a straight line perpendicular to the axis of rotation A and passing through both this axis of rotation and the trailing edge 26 of said blade 22 at the level of the junction between said trailing edge 26 and the support 30.

[0100] The second phase angle 98 is formed between, on the one hand, a straight line perpendicular to the axis of rotation A and passing through both this axis of rotation A and the leading edge 24 of a blade 22 at the level of the junction between said leading edge 24 and the annular band 38 and, on the other hand, a straight line perpendicular to the axis of rotation A and passing through both this axis of rotation A and the trailing edge 26 of said blade 22 at the level of the distal end of said trailing edge 26 of the support 30.

[0101] The first phase angle 96 may, in particular, be between 45° and 65°, preferably between 50° and 60°, more preferably between 53° and 57°. The second phase angle 98 is different from the first phase angle and can be between 30° and 55°, preferably between 35° and 50°, more preferably between 40° and 45°.

[0102] These first and second phase angles 96, 98 allow, on the one hand, to highlight the inclination of the blades 22 with respect to a radial line, perpendicular to the axis of rotation A, since these phase angles are of non-zero value, and they allow, on the other hand, to highlight the different inclination of the second edge 32 with respect to the inclination of the first edge 28, since these phase angles are of different values ​​from one angle to the other, which has in particular the effect of directing the airflow.

[0103] The complex shape of the blades, which makes it possible to efficiently direct the airflow towards the blades of the guide element, is also made visible in figures 10 to 12, which schematically illustrate the orientation of a blade 22 in different views.

[0104] Figure 5 illustrates a top view of the propeller 6 highlighting a feature of the invention in which the blades 22 are irregularly distributed on the support 30. In other words, the spacing between two adjacent blades 22 can vary around the circumference of the propeller. To this end, a circle 60 has been schematically represented by a dashed line, this circle 60 being centered on the axis of rotation A and passing through each of the ends of the leading edges 24 closest to the support 30.

[0105] This specific arrangement of the blades 22 of the propeller 6 is achieved in particular by an irregular distribution of the leading edges of the blades 22 around the axis of rotation A of the propeller 6. Indeed, as can be seen in [Fig. 5], the pitch, i.e., the distance, between the ends of the leading edges 24 closest to the support 30 of two adjacent blades 22 is different from the pitch between the ends of the leading edges 24 closest to the support 30 of two other adjacent blades 22. It should be noted that said pitch between two adjacent blades 22 is measured along the circle 60 between each of the ends of the leading edges 24 closest to the support 30.

[0106] In particular, it is noteworthy in [Fig. 5] that a pitch between two consecutive first blades 22a is equal to a first distance DI and a pitch between two consecutive second blades 22b is equal to a second distance D2, the first distance DI being different from the second distance D2. In the embodiment shown, and without limiting the invention, a pitch between two consecutive third blades 22c is equal to a third distance D3, different from the first distance DI and the second distance D2. Also, in an alternative embodiment of the invention, the pitches between two adjacent blades 22 are all different from each other.

[0107] It should be noted that this pitch between two adjacent blades 22 can be appreciated by characterizing an angular spacing defining an angle with respect to the axis of rotation A of the propeller 6 between the tip of a leading edge 24 of a blade 22 closest to the support 30 and arranged on the circle 60 and a tip of a leading edge 24 of an adjacent blade 22 closest to the support 30 and arranged on the circle 60. This angular spacing is schematically represented in [Fig. 5] by a first angular spacing 62 measured with respect to the axis of rotation A between two consecutive blades 22, and more precisely two leading edges 24. This first angular spacing 62 is different from a second angular spacing 64 measured with respect to said axis of rotation A between two other consecutive blades 22.

[0108] These differences, whether in terms of angular spacing or pitch, lead to the formation of varied airflow passage sections in the different circulation channels 40. Thus, the volume of air circulating in the different circulation channels 40 and the velocity of this airflow differ from one circulation channel 40 to another. These differences in both airflow velocity and volume allow for the diversification of the sound frequencies of the noises generated by the airflow and the propeller's movement, thereby limiting the noise perceptible to the vehicle user.

[0109] In the context of a fan motor assembly in which the propeller blades are said to be mixed to contribute to generating an airflow moving within the propeller first radially and then axially, the inventors observed that the passage of the trailing edges 26 of the blades 22 opposite a first edge 42 leads to a point compression of the airflow, thus creating noise at a given sound frequency. If the airflow is compressed by all the trailing edges 26 and the first edges 42 at the same time, the resulting sound frequency is overrepresented, causing acoustic discomfort for users. Therefore, making the arrangement of the propeller blades 22 irregular can ensure that at each moment of the propeller's rotation, some propeller blades 22 are not opposite an edge 42 of a guide blade while others are.This dispersion of the passing moments of the trailing edges 26 in relation to a first edge 42 of a blade 21 and the different volumes of air circulating in each circulation channel 40 thus make it possible to generate different sound frequencies formed by the passage of a blade 22 in relation to a blade 21 and to distribute them over a given time interval and thus limit the over-representation of a sound frequency at a given moment.

[0110] It should be noted that in [Fig. 5], the difference in angular spacing and pitch between the leading edges 24 of two adjacent blades is barely visible. Indeed, the differences in angular spacing and pitch are proportional to the diameter of the propeller 6. Also, in the embodiment shown, the propeller 6 has a small diameter, so that the differences in angular spacing and pitch are measured in millimeters. of course, the larger the diameter of the propeller 6, the more significant the irregular distribution of the blades 22 around the axis of rotation A.

[0111] In this context, the inventors were able to observe that an irregular angular distribution of the blades 22 around the axis of rotation A only has an effect if the number of blades 22 of the propeller is limited, a maximum number of blades being on the order of fifteen.

[0112] Figure 6 illustrates a top view of the second cylindrical part 18 of the housing 4, highlighting, in the embodiment shown, an irregular arrangement of the blades of the guide member, with at least one spacing between two adjacent blades 21 that differs from the spacing between two other adjacent blades 21. It should be noted that the spacing between two consecutive blades 21 may be equal to the spacing between two other consecutive blades 21.

[0113] As can be seen in this [Fig. 6], another circle 66 centered on the axis of rotation A and passing through all the first edges 42 of the blades 21 has been schematically represented. It should be noted that this circle 66 was constructed arbitrarily, and that other circles 66 can be constructed provided that these circles 66 are centered on the axis of rotation A and pass through all the first edges 42 of each blade 21.

[0114] Furthermore, this [Fig. 6] allows us to highlight a pitch and an angular dimension measured with respect to the axis of rotation A between the first edges 42 of two consecutive blades 21 and the first edges 42 of two other different consecutive blades 21. Indeed, as can be seen in this [Fig. 6], the first edge 42 of one blade 21 is a distance D4 from the first edge 42 of another adjacent blade 21. This distance varies between two consecutive blades 21 and two other consecutive blades 21. Also, two other first edges 42 of two other consecutive blades 21 are separated from each other by a distance D5 different from the distance D4. It should be noted that these distances between the first edges 42 of two consecutive blades 21 are measured along the circle 66 centered on the axis of rotation A from one first edge 42 to another.

[0115] The irregularity of the distribution of the blades 21 around the axis of rotation A can also be observed by an angular dimension measured from the axis of rotation A between a point located at the intersection of the circle 66 and the first edge 42 of a blade 21 and between a point located at the intersection of the circle 66 and the first edge 42 of a consecutive blade 21.

[0116] Thus, it is remarkable that two consecutive blades 21 are separated from each other by a first angular dimension 68 and two other consecutive blades 21 are separated from each other by a second angular dimension 70 different from the first angular dimension 68.

[0117] As described above, the differences in pitch and angular dimension between two consecutive blades ensure that the trailing edges 26 of the blades 22 are not aligned with the first edges 42 of the blades 21 simultaneously, thus preventing the occurrence of regular airflow compression between the blades and the guides at each regular passage of the blades past the guides. It is understood that, over a given propeller revolution, the trailing edge of a rotating blade is aligned with the first edges of the guides at irregular intervals, and that it is this irregularity that means that when one blade trailing edge is aligned with a guide blade and generates noise due to air compression, other blade trailing edges are not aligned with a guide blade, thereby preventing the overlapping of noise and the creation of a nuisance for the user.

[0118] In this context, in order to further improve the acoustics and avoid the risk of recurring sound frequencies appearing, it is ensured on the one hand that some of the angular spacing values ​​between two adjacent blades, respectively two adjacent blades, are different from each other and on the other hand that all the angular spacing values ​​between two blades are different from the angular spacing values ​​between two blades.

[0119] [Fig.7] illustrates a cross-sectional view of the motor-fan assembly 2 visible in [Fig.1] along a cross-sectional plane extending parallel to the axes L and V. As seen in [Fig.7], the first part 14 of the housing 4 has a general bell shape covering the propeller 6.

[0120] The first portion 14 of the housing 4 extends between a first end 72 and a second end 74, the first end 72 being closer to the air inlet 10 than the second end 74. The first portion 14 of the housing 4 has a shape substantially complementary to the shape of the blades 22 of the propeller 6 from the first end 72 to the second end 74. It should be noted that "substantially complementary" means that at least 90% of the extent defined between the first end 72 and the second end 74 is complementary to the shape of the blades 22.

[0121] This complementary shape of the first part 14 of the housing 4 and the blades 22 allows more specifically that the wall 76 of the first part 14 of the housing 4 has a shape complementary to the shape of the second edge 32 all along the latter, that is to say from the annular band 38 to the trailing edge 26. Thus, all along the second edge 32 from the annular band 38 to the trailing edge 26, the wall 76 is disposed at the same distance from the second edge 32.

[0122] As mentioned previously, the wall 76, together with the blades 21, forms part of the guiding element. Indeed, the wall 76 also helps to straighten the circulating airflow. from the air inlet 10 to the air outlet 12. The wall 76, together with the first face 34 of a blade 22, the second face 36 of an adjacent blade 22, and the support 30, helps to define a circulation channel 40 from the annular band 38 to the trailing edges 26 of the blades 22. At the second end 74 of the first part 14, the wall 76 extends substantially axially with respect to the axis of rotation A. Thus, when the airflow leaves the circulation channel 40, the portion of the airflow that comes into contact with the wall 76 is naturally directed axially towards the air outlet 12 and more precisely towards the blades 21.

[0123] The first part 14 of the housing 4 is attached to the second cylindrical part 18 of the housing 4 at a junction plane extending perpendicularly to the axis of rotation A. The junction between the first part 14 and the second part 18 is achieved by the fastening means 8, described previously, and a baffle 78 which helps to make the internal volume of the housing 4 airtight at said junction plane. This baffle 78 is formed by the interaction of a rib formed by the second part 18 of the housing 4 and a slot formed by the first part 14 of the housing 4. During the assembly of the first part 14 with the second part 18, the rib fits into the slot, thus increasing the distance that the airflow must travel to leave the internal volume of the housing 4 at this junction area.

[0124] As can be seen in [Fig.7], a radial end of the support 30 furthest from the axis of rotation A is disposed substantially at the level of the junction plane between the first part 14 and the second part 18 of the housing 4.

[0125] Upon leaving a circulation channel 40, the airflow is directly directed into the second part 18 of the housing 4. Unlike what would occur in the case of a propeller with purely radial blades, with a trailing edge substantially parallel to the axis of rotation and the housing wall, here the airflow is prevented from striking the wall at a substantially right angle, thus smoothing the airflow circulation and limiting pressure loss. This is due in particular to the fact that the trailing edge 26 has a free end 27, opposite the support 30 from which the trailing edge 26 protrudes, and that the trailing edge is inclined so that this free end extends radially beyond the support 30, as close as possible to the housing wall that helps define the propeller housing cavity.

[0126] The housing 4, and more particularly the second portion 18 of the housing 4, helps to define an annular conduit 80 extending parallel to the axis of rotation A. As previously described, the blades 21 are fixed to the first portion 46 of the second portion 18 of the housing 4 and to the second portion 50 of the second portion 18 of the housing 4. The first portion 46 and the second portion 50 help to define the annular conduit 80. More specifically, the annular conduit 80 includes an internal peripheral edge 82 formed from part of the first portion 46 and an external peripheral edge 84 formed from part of the second portion 50.

[0127] At least one blade 21 of the guide member, in the embodiment shown all the blades 21, extends across this annular conduit 80 by being fixed to the inner peripheral edge 82 of the annular conduit 80 and to the outer peripheral edge 84 of said annular conduit 80. The inner peripheral edge 82 is opposite the outer peripheral edge 84.

[0128] In addition, the inner peripheral edge 82 helps to delimit a first cavity 86 in which the stator, not shown here, of the drive unit is housed.

[0129] This architecture of the motor-fan group 2 allows an airflow FA, symbolized by arrows, to enter the housing 4 in an axial direction, i.e. parallel to the axis of rotation A, and to flow at the level of the propeller 6 radially towards the wall 76 of the guide member and then to be straightened by the cooperation of said wall 76 and the specific curvature of the blades 22 towards the air outlet 12 via the guide member, whose blades also participate in straightening the airflow FA so that the airflow FA exits the housing 4 through the air outlet 12 in an axial direction.

[0130] [Fig.8] illustrates a detailed view of the motor-fan assembly 2 visible in [Fig.7]. More specifically, [Fig.8] illustrates in detail the arrangement of a trailing edge 26 of a blade 22 opposite a first edge 42 of a blade 21.

[0131] As mentioned previously, the wall 76 has a shape complementary to the second edges 32 of the blades 22. Therefore, the free end 27 of the trailing edge 26 of a blade 22 of the propeller 6, that is, the trailing edge end furthest from the axis of rotation A of the propeller 6, is at a distance of less than 6 mm from the wall 76 of the guide element. It is understood that this distance is a function of the dimensions of the motor-fan assembly. It can also be considered that this distance between the free end of the trailing edge and the wall defining the first part of the housing is less than 5% of the distance between the axis of rotation and this wall. In both cases, the distance is measured perpendicular to the axis of rotation of the propeller.

[0132] This small distance between the wall 76 of the guide element and the trailing edge 26 of the blades 22, and more particularly the free end 27 of this trailing edge 26, helps to limit the formation of turbulence. Indeed, when the distance between the wall 76 of the first part 14 and the trailing edge 26 is large, the airflow is disturbed and the air pressure between the wall 76 and the trailing edge 26 increases. This pressure increase contributes to creating noise pollution for users. Thus, by placing the wall 76 at a small distance from the edges leakage 26 from the blades 22, the airflow circulates towards the blades 21 without forming turbulence which limits the localized increase in pressure within the housing 4.

[0133] Furthermore, it is particularly noteworthy in [Fig. 8] that the distance between a first edge 42 of a blade 21 and the trailing edge 26 of a blade 22 closest to said first edge 42 increases as the distance from the axis of rotation A of the propeller 6 increases. This increase in distance is schematically represented by a distance D6 measured near the support 30 and parallel to the axis of rotation A between the first edge 42 of a blade 21 and the trailing edge 26 of a blade 22 arranged opposite it, which is smaller than a distance D7 measured near the wall 76 and parallel to the axis of rotation A between said first edge 42 and said trailing edge 26.

[0134] This increase in the distance between the trailing edge 26 and the first edge 42 as the distance from the axis of rotation A increases makes it possible to avoid the phenomenon of compression of the airflow between said trailing edge 26 and said first edge 42 at the radial end of the propeller, that is to say in the area where the airflow has the most speed and could generate significant noise in the event of compression.

[0135] In this way, a good compromise is achieved between, on the one hand, the need according to the invention to have trailing edges of the propeller blades that are as close as possible to the blades and to the inner face of the first part 14 of the housing containing the propeller, for the efficiency of guiding the airflow without pressure losses, and on the other hand, the need to have trailing edges that are sufficiently far from the guide blades to avoid strong air compression and noise that could be disturbing to the vehicle user.

[0136] Figure 9 illustrates more specifically the inclination of the leading edge 24 of a blade 22 with respect to the axis of rotation A and the inclination of the trailing edge 26 of said blade 22 with respect to the axis of rotation A. It should be noted that to facilitate the reading of [Fig.9], [Fig.9] is made very schematically in two dimensions so that the leading edge 24 and the trailing edge 26 of the blade 22 shown extend in the same plane.

[0137] As remarkable on [Fig.9], the leading edge 24 of the blade 22 forms an entry angle 100 with a first axis Al extending parallel to the axis of rotation A and passing through said leading edge 24 at the level of the junction between the leading edge 24 and the support 30, this entry angle 100 being able to be between 30° and 55°, preferably between 35° and 50°, more preferably between 40° and 45°.

[0138] Furthermore, the trailing edge 26 of said blade 22 forms an exit angle 104 with a second axis A2 extending perpendicularly to the axis of rotation A and passing through the trailing edge 26 at the junction between the trailing edge 26 and the support 30, this exit angle 104 can be between -15° and 15°, preferably between 5° and 15°, more preferably between 10° and 15°.

[0139] It follows from these leading and trailing edge inclination values ​​that the blade inlets 22 have a conical shape defined by the inclination of the leading edges around the axis of rotation, and that the outlet is substantially flat. It should be noted that for the trailing edge inclination, an outlet angle 104 of 90° corresponds to an orientation of the trailing edge perpendicular to the axis of rotation A. Such an orientation, and where applicable a negative angle inclination, i.e., tending to direct the trailing edge towards a corresponding blade of the guide element, is accompanied by a specific shape of the first edge 42 of the blade, not visible in [Fig. 9], in order, as previously mentioned, to avoid the phenomenon of airflow compression.

[0140] As just described in detail, the present invention achieves the goal it set for itself by proposing an architecture of a motor-fan unit in which the airflow enters a housing of the motor-fan unit through an air inlet and exits the housing through an air outlet in an axial direction parallel to an axis of rotation of a propeller of the motor-fan unit, being at least partially straightened in said axial direction by blades of the propeller.

[0141] The present invention is not limited to the means and configurations described and illustrated herein and also extends to any equivalent means and configuration as well as to any technically operative combination of such means.

Claims

Demands

1. A motor-fan assembly (2) comprising at least one housing (4) defining an internal volume between an air inlet (10) and an air outlet (12), the motor-fan assembly (2) comprising at least one impeller (6) housed within the internal volume of the housing (4) and a guide member, the impeller (6) being configured to be driven in rotation about an axis of rotation (A) and to force an axial inlet, along the axis of rotation (A), of an airflow into the housing (4) through the air inlet (10), the impeller (6) comprising a support (30) and a plurality of blades (22) distributed about the axis of rotation (A) and extending radially from a leading edge (24) to a trailing edge (26), the leading edge and trailing edge of each blade projecting from said support, the guide member being formed of at least a plurality of blades (21) arranged circumferentially around the axis of rotation (A) between the propeller (6) and the air outlet (12),said blades (21) being configured to direct axially, along the axis of rotation (A), the airflow towards the air outlet (12), characterized in that at least one blade (22) of the propeller (6) comprises a first face, or lower surface, (34) extending between the leading edge (24) and the trailing edge (26) of a blade (22) and along which the airflow passing between two adjacent blades is intended to flow mainly, said lower surface having a curvature with a proximal portion (224) closest to the leading edge (24) extending opposite a second face, or upper surface, (36) of the adjacent blade to define a substantially radial airflow duct and at least one other portion, opposite the proximal portion, which is folded down to extend opposite the support (30) and / or opposite a blade of the guide element to axially delimit said airflow circulation duct.

2. Motor-fan group (2) according to claim 1, wherein at least one blade is configured such that its intrados (34) has a distal portion, opposite said proximal portion (224), which extends radially beyond the support (30) in relation to a blade (21) of the guide member.

3. Motor-fan assembly (2) according to claim 1 or 2, wherein the trailing edge (26) of at least one propeller blade (6) extends radially beyond the support (30) and has a inclination relative to the axis of rotation (A) of the propeller (6) so as to be opposite at least one blade (21) of the guide member.

4. Motor-fan assembly (2) according to the preceding claim, wherein at least one blade (22) is fixed to the support at a first edge (28), the trailing edge (26) of at least one blade (22) having an end connected to the support (30) and an opposite end which forms a free end (27), at the junction of this trailing edge (26) and a second edge (32).

5. Motor-fan assembly (2) according to the preceding claim, wherein said free end of the trailing edge is the end furthest from the axis of rotation (A) of the propeller (6), extending to a distance from a wall (76) defining the first part (14) of the housing which is less than 5% of the distance between the axis of rotation and said wall, said distance being measured perpendicular to the axis of rotation of the propeller.

6. Motor-fan assembly (2) according to any one of the preceding claims, wherein the housing (4) is formed of at least a first part (14) housing the propeller (6) and a second part (18) within which the blades (21) of the guide member extend, the first part (14) of the housing (4) extending between a first end (72) and a second end (74), the first end (72) being closer to the air inlet (10) than the second end (74), the first part (14) of the housing (4) having a shape substantially complementary to the shape of said blades (22) of the propeller (6) from the first end (72) to the second end (74).

7. Motor-fan assembly (2) according to claim 6, wherein the support (30) extends so that an axial end of this support closest to the blades (21) of the guide member is substantially at the level of a junction plane between the first part (14) of the housing (4) and the second part (18) of the housing (4).

8. Motor-fan assembly (2) according to any one of claims 1 to 7, wherein the leading edge (24) of a blade (22) extends along a first principal extension direction and the trailing edge (26) of said blade (22) extends along a second principal extension direction, the first the main extension direction and the second main extension direction being secant to the axis of rotation (A).

9. Motor-fan assembly (2) according to any one of claims 1 to 8, wherein the trailing edge (26) of a blade (22) is angularly offset from the leading edge (24) of said blade in the direction of rotation of the propeller (6).

10. Motor-fan assembly (2) according to any one of claims 1 to 9, wherein the blades (22) of the propeller (6) are distributed irregularly around the axis of rotation (A) of the propeller (6).

11. Motor-fan group (2) according to claim 10, wherein a first angular spacing (62) measured with respect to the axis of rotation (A) between two consecutive blades (22) is different from a second angular spacing (64) measured with respect to said axis of rotation (A) between two other consecutive blades (22).

12. Motor-fan assembly (2) according to any one of claims 1 to 11, wherein an angular separation measured with respect to the axis of rotation (A) between two consecutive blades (22) is different from an angular dimension measured with respect to said axis of rotation (A) between two consecutive blades (21).

13. Motor-fan assembly (2) according to any one of claims 1 to 12, wherein the distance between a first edge (42) of two adjacent blades (21) is variable from one pair of adjacent blades to another pair of adjacent blades.

14. Motor-fan assembly (2) according to any one of the preceding claims, wherein the distance between a blade (21) and the trailing edge (26) of a blade (22) opposite said blade (21) increases as the distance from the axis of rotation (A) increases.

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