FR3074237A1 - MOTOR FAN GROUP FOR MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a fan motor unit (1) comprising a wheel (5) and a volute (3) adapted to be mounted on a heating / ventilation and / or air conditioning system, - said wheel comprising a hub (15) adapted for mounting on a motor shaft (9a), and a peripheral ring (17) provided with a succession of blades (19); - said volute being adapted to receive said wheel and having an inner wall (30) adapted to evolve in part in a radial angular evolution, an air inlet (3c) and an air outlet (3d); characterized in that: - said wheel comprises at least one blade whose angle of attack (β1) is between 67 ° and 79 °; the ratio between the inside diameter (D1) and the outside diameter (D2) of the wheel is between 75% and 85%; and said volute comprises a development angle (α) of between 4.7 ° and 4.9 °.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a motor-fan unit for a motor vehicle.

It finds a particular, but not limiting, application in motor vehicles.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

The present invention relates to the field of air blowers adapted to be mounted on a heating, ventilation and / or air conditioning system for a motor vehicle (generally designated by the acronym HVAC for "Heating, Ventilating and / or AirConditioning") .

More particularly, the present invention relates to a fan unit for a heating, ventilation and / or air conditioning system for a motor vehicle.

It will be noted that a heating, ventilation and / or air conditioning system for a motor vehicle is a housing, generally placed under the dashboard of the motor vehicle.

Said heating, ventilation and / or air conditioning system includes:

- at least one air inlet, outside or inside;

- at least one air outlet opening into the passenger compartment of the motor vehicle;

- air ducts in which are arranged one or more heat exchangers which will make it possible to thermally condition (that is to say heat or cool) an air flow passing through them (said air flow being intended to lead into the passenger compartment of the motor vehicle via said at least one air outlet).

It is also necessary for the heating / ventilation and / or air conditioning system to be equipped with a motor-fan unit in order to generate an air flow that is large enough for said air flow to pass through the heat exchangers and lead into the passenger compartment of the motor vehicle. Thus, the air flow generated by the motor-fan unit must be adapted to compensate for the pressure losses caused by said exchangers and / or the air ducts of said housing.

More particularly, the motor-fan unit comprises an engine support, a motor housed in the engine support and a centrifugal type wheel mounted on the engine shaft of the engine. The motor of the fan unit is for example an electric motor.

The motor-fan unit is also mounted on the heating, ventilation and / or air conditioning system at a volute. The volute is for example defined by the walls of the housing of the heating, ventilation and / or air conditioning system. It will be noted that the volute is an air duct having a variable section, generally mathematically determined, which guides the flow of an air flow. In the automotive field, the volute comprises a volute air inlet and a volute air outlet which are arranged substantially orthogonally to one another.

The wheel arranged in the volute makes it possible to suck the air axially through the air inlet of the volute (that is to say along an axis substantially parallel to the axis of revolution of the wheel) and to discharge radially (that is to say along an axis substantially orthogonal to the axis of revolution of the wheel) the air thus sucked in by the air outlet from the volute.

It should be noted that the assembly "motor-fan group and volute" is generally designated by the term "air blower".

This type of motor-fan unit also requires meeting many technical requirements, such as acoustics, motor energy consumption, motor torque, the volume flow rate of the air flow generated by the blower d air, etc.

It is generally sought to optimize the transformation of the mechanical power, delivered by the engine via the motor shaft, into a ventilation power delivered via the air blower wheel.

If we consider an aeraulic efficiency defined as the ratio of aeraulic power to mechanical power, it is thus sought to have an aeraulic efficiency closest to 1, this indicating that the transformation of mechanical power into aeraulic power is performs with the least possible losses.

GENERAL DESCRIPTION OF THE INVENTION

Thus, the present invention proposes to improve the ventilation efficiency of a motor-fan unit and relates to a motor-fan group comprising a wheel and a volute adapted to be mounted on a heating / ventilation and / or air conditioning system for a vehicle. automotive,

- said wheel comprising:

- a hub capable of being mounted on a drive shaft;

- a peripheral crown provided with a succession of blades, said hub and the peripheral crown being connected to each other;

- said volute comprising:

- an internal wall adapted to evolve in part according to a radial angular evolution;

- an air inlet and an air outlet;

and being adapted to receive said wheel, said wheel being adapted to be arranged in said volute coaxially around a motor of said motor-fan unit;

characterized in that:

- Said wheel comprises at least one blade whose angle of attack is between 67 ° and 79 °;

- the ratio between the inside diameter and the outside diameter of the wheel is between 75% and 85%; and

- said volute comprises a development angle of between 4.7 ° and 4.9 °, said development angle being the angle between said internal wall of said volute and said peripheral ring of said wheel.

Surprisingly, and in spite of numerous parameters capable of being modified, the fact of designing a motor-fan unit having the characteristics set out above makes it possible to improve the energy efficiency of the motor-fan group. More particularly, it has been found, compared with an air blower of the prior art and with identical aeraulic power, that the mechanical power required was lower and that therefore the aeraulic efficiency of the motor-fan unit was improved.

According to non-limiting embodiments, the fan unit can also include one or more additional characteristics among the following:

According to a nonlimiting embodiment, said wheel has a height of between 60 mm and 90 mm.

The motor-fan unit wheels, which have a height of between 65 and 85 mm, have further improved performance.

According to a nonlimiting embodiment, said peripheral ring comprises a succession of blades configured to draw air axially from the inside of the wheel and to discharge it radially towards the outside of the wheel.

The term "axially" means that the air is sucked along an axis substantially parallel to the axis of revolution of the wheel.

According to a nonlimiting embodiment, the hub is connected to the peripheral crown by means of a connecting means. Said connecting means is, for example, mechanical, such as an open surface or a closed surface.

Generally, the connecting means which connects the hub to the peripheral crown defines a generally concave envelope in the form of a bowl. This form is preferably chosen for reasons of acoustics.

The connecting means is connected for example with the hub at the center of the bowl and with the crown at the periphery of the bowl.

According to a nonlimiting embodiment, the wheel has an outside diameter between 135 mm and 165 mm, and preferably between 140 and 160 mm.

The fan unit wheels which have a diameter as indicated above have further improved performance.

According to a nonlimiting embodiment, said wheel comprises at least one blade whose leakage angle is between 155 ° and 167 °.

The fan-motor unit wheels which comprise at least one blade as indicated above have further improved performance.

The vanishing angle of a blade corresponds to the angle between the air flow and the outer transverse end of a blade.

According to a nonlimiting embodiment, the ratio between the inside diameter and the outside diameter of the wheel is between 78.3% and 80.3%.

The fan-motor unit wheels, which have a ratio between the inside diameter and the outside diameter of the wheel, which is between 78.3% and 80.3%, display even better performance.

According to a nonlimiting embodiment, the ratio between the inside diameter and the outside diameter of the wheel is between 78.8% and 79.8%.

The fan-motor unit wheels which have a ratio between the inside diameter and the outside diameter of the wheel as indicated above display performances which are still improved compared to the values previously indicated.

According to a nonlimiting embodiment, the angle of attack is between 70 ° and 76 °.

According to a nonlimiting embodiment, the angle of attack is between 72 ° and 74 °.

The fan-motor unit wheels which have one or more blades with an angle of attack as indicated above display performances which are still improved compared to the previous values.

According to a nonlimiting embodiment, said wheel comprises at least one blade which has a thickness between 0.8 mm and 2.1 mm, and preferably between 0.9 and 2 mm.

An air blower wheel with one or more blades which have a thickness as indicated above displays the best compromise between airflow efficiency and noise pollution.

According to a nonlimiting embodiment, the thickness of the blade is preferably constant, however due to the manufacturing methods, the thickness of the blade can vary by a single or double over the height of said wheel.

According to a nonlimiting embodiment, said volute comprises a cut defined between a start of the radial angular evolution of said volute and an edge of said air outlet, said cut being defined by a cut angle of between 45 ° and 65 °. This improves the ventilation efficiency of the motorized fan unit.

In a preferred non-limiting variant embodiment, the cutting angle is between 52 ° and 59 °.

In a very preferred non-limiting variant, the cut-off angle is between 52 ° and 55 °.

According to a nonlimiting embodiment, said cut is between 9% and 11% of the outside diameter of said wheel.

This allows the value of the cut-off radius to be adapted to the dimension of the air blower.

According to a nonlimiting embodiment, said volute comprises a cutting distance of between 8% and 10% of the outside diameter of said wheel. This improves the ventilation efficiency of the fan unit.

In a preferred non-limiting alternative embodiment, the cut-off distance is between 9.2% and 10% of the outside diameter of said wheel.

In a very preferred non-limiting variant, the cut-off distance is between 9.3% and 9.7% of the outside diameter of said wheel.

The cut-off distance corresponds to the distance between the internal wall at the start of the cut-off (i.e. at the start of the radial angular evolution) and the peripheral crown of the wheel.

According to a nonlimiting embodiment, said wheel has an outside diameter between 130mm and 165mm.

In a preferred nonlimiting variant embodiment, said peripheral ring of said wheel comprises an outside diameter of between 136mm and 142mm.

In a very preferred non-limiting variant, said peripheral ring of said wheel comprises an outside diameter of between 136mm and 141mm.

According to a nonlimiting embodiment, said scroll has a first radial dimension between 175mm and 212mm and a second radial dimension perpendicular to the first radial dimension between 195mm and 246mm. This improves the ventilation efficiency of the motorized fan unit

In a preferred non-limiting alternative embodiment, said scroll has a first radial dimension between 186mm and 202mm.

In a preferred non-limiting alternative embodiment, said scroll has a second radial dimension between 228mm and 232mm. In a very preferred non-limiting variant, said scroll has a first radial dimension between 190mm and 202mm.

In a very preferred non-limiting variant, said scroll has a second radial dimension between 229mm and 232mm.

According to a nonlimiting embodiment, said air outlet comprises a substantially rectangular section and comprises a height between 85mm and 110mm and a width between 35mm and 65mm. This reduces the size of the motor-driven fan assembly.

In a preferred non-limiting variant embodiment, said air outlet comprises a height of between 85mm and 104mm.

In a preferred non-limiting variant embodiment, said air outlet comprises a width of between 56mm and 65mm.

In a very preferred non-limiting variant embodiment, said air outlet comprises a height of between 85mm and 95mm.

In a very preferred non-limiting variant embodiment, said air outlet comprises a width of between 56mm and 62mm.

According to a nonlimiting embodiment, the radial angular evolution of the internal wall is an exponential radial angular evolution.

According to a nonlimiting embodiment, the motor-fan unit comprises decoupling means arranged between the motor and the motor support.

According to a nonlimiting embodiment, the motor-fan unit comprises an engine control module. Said motor control module is for example mounted on the motor support of the motor-fan unit.

The invention also relates to a heating, ventilation and / or air conditioning system for a motor vehicle comprising a fan unit according to any one of the preceding characteristics.

BRIEF DESCRIPTION OF THE FIGURES

The invention and its various applications will be better understood on reading the description which follows and on examining the figures which accompany it:

- Figure 1 shows a schematic view of a motor fan unit for a heating, ventilation and / or air conditioning system, according to a non-limiting embodiment;

- Figure 2 shows a perspective view of the fan motor assembly of Figure 1 and a part, defining scroll, according to a non-limiting embodiment;

- Figure 3 is a partially broken away view of Figure 1, according to a non-limiting embodiment;

- Figure 4 is an exploded and perspective view of the elements shown in Figure 1, according to a non-limiting embodiment;

- Figures 5a to 5d show perspective and top views of a wheel of the fan motor assembly of Figure 1, according to non-limiting embodiments;

- Figure 6 is an enlarged view of the blades of the wheel shown in Figure 5c;

- - Figure 7 is a cross-sectional view of a blade shown in Figure 6;

- - Figure 8 is a longitudinal sectional view of the wheel shown in Figure 5c;

- Figure 9 is a schematic cross-sectional view of a scroll of Figure 1, according to a non-limiting embodiment;

- Figure 10 is a schematic cross-sectional view of a radial angular evolution of the scroll of Figure 9, according to a non-limiting embodiment.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Identical elements, by structure or by function, appearing in different figures keep, unless otherwise specified, the same references.

Figure 2 is a schematic perspective view of a motor fan group 1 and part 3, defining volute, of a heating, ventilation and / or air conditioning HVAC system for a motor vehicle, the motor fan group being mounted on the HVAC heating, ventilation and / or air conditioning system.

It will be noted that a heating, ventilation and / or air conditioning HVAC system for a motor vehicle is a box, generally placed under the dashboard of the motor vehicle, which comprises:

- at least one air inlet, outside or inside;

- at least one air outlet opening into the passenger compartment of the motor vehicle;

- air ducts in which are arranged one or more heat exchangers which will allow to thermally condition (i.e. heat or cool) an air flow passing through them.

Said air flow is intended to terminate in the passenger compartment of the motor vehicle by means of said at least one air outlet from said housing. A HVAC heating, ventilation and / or air conditioning system for a motor vehicle is illustrated diagrammatically in FIG. 1 in a nonlimiting embodiment. He understands :

- a motor-fan unit 1 with a volute 3, delivering an air flow F1 in an air channel 8;

- said air channel 8;

- an evaporator 4 of a refrigeration circuit (when the air conditioning function is present) arranged in the air channel 8;

- A heat sink 5 liquid heat exchanger disposed in the air channel 8 and traversed by a coolant of the electric motor of the motor vehicle; and

- optionally an additional electric heat sink 6 arranged in the air channel 8.

In air conditioning mode, the air flow F1 is deflected in a passage 7 bypassing a heat sink 5. Downstream of the heat sinks 5 and 6, the air channel 8 distributes the air flow F1 to the outlets exit in the passenger compartment of the motor vehicle. The distribution and optionally the mixing of the F1 air flow is done using controlled flaps (not shown). Mixing allows temperature regulation of the F1 air flow before distribution in the passenger compartment. Since distribution and mixing are known to those skilled in the art, they are not described here.

It is, moreover, necessary that the heating / ventilation and / or air conditioning HVAC system is equipped with a motor-fan unit in order to generate an air flow which is large enough for said air flow to pass through the or heat exchangers and thus compensate for the pressure losses generated by said exchangers and / or air ducts.

A minimum pressure value is generally defined, denoted for example ΔΡ, that the motor-fan unit must produce in order to generate a sufficient air flow for the latter to pass through one or more heat exchangers and the ducts of the heating system, HVAC ventilation and / or air conditioning and lead into the passenger compartment, this for a given air volume flow (the minimum pressure value ΔΡ must therefore be equal to or greater than the pressure drops). There are, moreover, requirements as to the duration for which the air in the passenger compartment has been completely renewed, this in order to avoid odors and / or the accumulation of pathogenic agents in the passenger compartment.

As illustrated in FIG. 2, the part of the casing defining volute 3 generally comprises two parts, lower and upper (respectively 3a and 3b), the internal surfaces of the walls of which make it possible to define an air duct having a variable section, generally mathematically determined, which guides the flow of an air flow F1.

Said volute 3 furthermore comprises a volute air inlet 3c and a volute 3d air outlet. The volute air inlet 3c is connected to the air inlets (interior and / or exterior) of the HVAC heating, ventilation and / or air conditioning system, while the 3d air outlet is connected to one or more outlets air from the HVAC heating, ventilation and / or air conditioning system that ends up in the passenger compartment of the motor vehicle. It will be noted that the inlet 3c and volute air outlet 3d are arranged substantially orthogonally to one another.

It should be noted that the assembly "motor-fan group and volute" is generally designated by the term "air blower".

The motor-fan unit 1 thus comprises a wheel 5 of the centrifugal type which is configured to draw air axially (that is to say along an axis substantially parallel to the axis of revolution of the wheel), by the intermediate the air inlet 3c of the volute, and to discharge the air thus sucked radially (that is to say along an axis substantially orthogonal to the axis of revolution of the wheel), so the air is evacuated by the 3d air outlet of the volute 3.

Thus, as can be seen in FIGS. 2 and 3, the fan unit 1 comprises:

- a volute 3;

- a centrifugal type wheel 5;

- an engine support 7;

- A motor 9 housed in the motor support, said motor 9 being for example an electric motor.

Said motor 9 further comprises a motor shaft 9a on which the wheel 5 is mounted.

Furthermore, in an embodiment not shown, the motor-fan unit 1 comprises decoupling means arranged between the motor and the motor support.

According to another embodiment not shown, the fan unit 1 comprises an engine control module, said engine control module being, for example, mounted on the engine support of the motor-fan unit.

The wheel 5 is the means which allows the rotation of the motor shaft 9a to be transformed into an air flow which is characterized by a pressure difference ΔΡ and a volume flow of air and, which passes through the volute, as well as the HVAC heating, ventilation and / or air conditioning system.

The mechanical power corresponds to the product of the speed of rotation of the motor shaft 9a by the mechanical torque delivered by said motor shaft 9a.

The air power corresponds to the product of the volume flow of air and the pressure difference generated by the wheel.

Thus, the fact of improving the aeraulic power or of maintaining an identical aeraulic power for a lower mechanical power makes it possible to improve the aeraulic efficiency of the motor-fan group, the aeraulic efficiency being the ratio of the aeraulic power to the power mechanical.

In fact, if the mechanical power to be supplied is less, the electric power to be supplied to the electric motor will be less. Thus, for an identical aeraulic power, the electric consumption of the engine will be less important.

The wheel 5 and the volute 3 are described in more detail below.

• Wheel 15

FIGS. 5a to 5d show perspective and top views of non-limiting embodiments of the wheel 5.

More particularly, the wheel 5 comprises:

- a hub 15 adapted to be mounted on a motor shaft 9a;

- A peripheral crown 17 provided with a succession of blades 19; said hub 15 and the peripheral ring 17 being connected to each other. In the exemplary embodiments presented, the connection means is a mechanical connection.

The wheel 5 comprises at least one blade 19.

Note that a blade has an elongated shape. The longitudinal axis of a blade is substantially parallel to the axis of revolution of the wheel. A blade therefore has two opposite longitudinal ends and two opposite transverse ends.

Furthermore, the centrifugal type wheel 5 has a generally cylindrical shape and an axis of revolution passing through the hub 15. This axis of revolution defines an axis of rotation A illustrated in FIG. 1 of the fan unit 1.

Said wheel 5 also has a height and an outside diameter D2.

By height is meant the spatial extension of the wheel 5 along an axis substantially collinear with the axis of revolution of the wheel 5.

The term outside diameter D2 is understood to mean the radial extension of the wheel (the outside diameter of the wheel 5 being included in a plane substantially orthogonal to the axis of revolution of said wheel 5).

In a nonlimiting embodiment, the outside diameter D2 is between 130mm and 165mm. In a preferred non-limiting variant embodiment, the outside diameter is between 136mm and 142mm. In a very preferred non-limiting variant embodiment, the outside diameter is between 136mm and 141mm.

The wheel 5 also has an internal diameter D1.

By inner diameter D1 is meant the radial inner extension of the wheel 5 (that is to say the outer diameter from which the distance occupied by the blades 19 of the wheel 5 would have been subtracted).

In a nonlimiting embodiment, the wheel 5 comprises at least one blade 19 whose angle of attack is between 67 ° (degrees) and 79 ° (degrees).

The angle of attack of a blade 19 is understood to mean the angle of incidence of the air flow on the internal transverse end of the blade 19.

In addition, in a nonlimiting embodiment, said wheel 5 has a ratio between its internal diameter D1 and its external diameter D2 which is between 75% and 85%.

Such a wheel 5 improves the ventilation efficiency of the motor-fan unit, while reducing the noise nuisance generated by the rotation of the wheel. The wheel 5 makes it possible to reduce the necessary torque supplied by the motor shaft and / or the speed of rotation of said shaft while ensuring identical aeraulic performance (that is to say for an equivalent pressure and volume flow of air ).

More particularly, said peripheral ring 17 is provided with a succession of blades 19 configured to draw air axially from inside the ring 17 and to discharge it radially towards the outside of the wheel 5.

The term "axially" means that the air is sucked along an axis substantially parallel to the axis of revolution A of the wheel. Generally, the axis of revolution A of the wheel 5 passes through the hub 15 of the said wheel.

The hub 15 is connected to the peripheral ring 17 via a connecting means 21. The connecting means 21 defines a generally concave envelope in the form of a bowl, the latter can be closed (visible for example in the figure 5a) or open (visible for example in Figures 5b, 5c and 5d).

The connecting means 21, also called the bowl of the wheel, is for example an open surface (this is pierced with openings of variable sizes (see for example Figures 5c and 5d), an open surface comprising a plurality of arms (see Figure 5b) which connects the hub 15 to said surface, or closed (see Figure 5a).

The fact that the connecting means 21 is open is generally conditioned by the need to devote part of the air flow generated by the wheel 5 to cooling the motor 9.

However, a closed connection means 21 has the advantage of generating less noise than an open connection means 21.

Said connecting means 21 is connected for example with the hub 15 at the center of the bowl and with the crown 17 at the periphery of the bowl.

Furthermore, it will be noted that the wheel 5 generally comprises a connection ring 23 situated at the end opposite to the crown 17 which connects the blades 19 of the wheel with each other, this connection ring of 23 makes it possible to strengthen the mechanical cohesion of the wheel 5.

FIG. 6, for its part, is an enlarged view of blades 19 of the wheel 5.

Each of the blades 19 has an elongated shape and whose longitudinal extension is substantially parallel to the axis of revolution of the wheel 5 (that is to say that the longitudinal axis of a blade is substantially parallel to the axis of revolution of the wheel). Each of the blades therefore has opposite longitudinal ends.

In addition, said opposite longitudinal ends of a blade 19 are respectively connected to the peripheral ring 17 and to the connecting ring 23.

In addition, a blade 19 has, seen in section, an arcuate profile (more particularly visible in FIG. 7). The sectional view corresponds to a section plane substantially orthogonal to the longitudinal axis of a blade.

Each of the blades 19 has a first transverse end and a second transverse end, said first and second transverse ends being opposite 19a, 19b relative to one another. Said first transverse end 19a, also called external transverse end, extends away from the hub 15 of said wheel 5 (that is to say that the first transverse end is oriented towards the outside of the wheel).

Said second transverse end 19b, also called internal transverse end, extends in the direction of the hub 15 of said wheel 5 (that is to say that the second transverse end is oriented towards the inside of the wheel).

The first transverse end 19a can also be designated by the term “trailing end”, while the second transverse end, for its part, 19b can be designated by the term “leading end” (one can also speak respectively "trailing edge" and "leading edge").

It will also be noted that the distance between each of the opposite transverse ends 19a and 19b of a blade 19 is called the cord C (more particularly visible in FIG. 7), the cord C corresponds to the distance between the two ends of the blade , distance from the concave side of said blade.

In addition, as each of the blades 19 has an arcuate profile, each of the blades has a concave and a convex face opposite one another.

As illustrated in Figure 7:

each of the blades 19 has an angle of attack β1; the angle of attack β1 of a blade corresponds to the angle between the tangent t2 to the concave face of the second end 19b of the blade and the normal t1 at said end 19b (the normal being substantially tangent to the internal diameter of wheel).

Each of the blades 19 has a leak angle β2; the vanishing angle β2 of a blade corresponds to the angle between, on the one hand, the tangent t4 to the concave face of the first end 19a and, on the other hand, the tangent t3 of the outside diameter of the wheel at the point of intersection between the outside diameter of the wheel and the tangent to the concave face of the first end 19a.

The thickness (e) of a blade 19 corresponds to the distance between the opposite longitudinal faces of a blade, that is to say the distance between the concave and convex faces of a blade.

Thus, according to non-limiting embodiments, said air blower wheel 5 comprises at least one blade 19 having one or more of the following characteristics:

The angle of attack β1 of a blade (19) is between 67 ° and 79 °, and preferably between 70 ° and 76 °, and even more preferably between 72 ° and 74 °.

The thickness e of the blade 19 is between 0.8 mm and 2.1 mm, and preferably between 0.9 mm and 2 mm.

The vanishing angle β2 of a blade 19 is between 155 ° and 167 °, and preferably between 157 ° and 165 °, and even more preferably between 159 ° and 163 °.

As illustrated in Figure 8:

The outer diameter D2 of wheel 5 corresponds to the radial extension of the wheel 5, that is to say to a straight line extending from one outer radial end to the other of the wheel 5 and passing through the axis of revolution A of this (generally the external diameter of the wheel corresponds to the diameter of the peripheral crown or of the connecting ring).

The internal diameter D1 of wheel 5 corresponds to the internal radial extension of the wheel, that is to say to a straight line extending from an internal transverse end 19b of one blade 19 to another 19b and passing through the axis of revolution A of the wheel 5.

The height H of the road 5 corresponds to the longitudinal extension of the wheel 5.

Thus, according to non-limiting embodiments, said air blower wheel 5 has one or more of the following characteristics:

The ratio between the inside diameter D1 and the outside diameter D2 of the wheel 5 is between 75% and 85%, and preferably between 78.3% and 80.3%, and even more preferably between 78.8% and 79, 8%.

The wheel 5 has an outside diameter D2 of between 135 mm and 165 mm, and preferably between 140 and 160 mm.

Said wheel 5 has a height H of between 60 mm and 90 mm, and preferably between 65 and 85 mm.

It will be noted that the wheel 5 preferably comprises at least 50% of blades having one or more of the characteristics set out above, and even more preferably all of the blades of said wheel 5 have one or more of the characteristics set out above.

• Volute 3

The volute 3 is illustrated seen from above in FIGS. 1 to 4, and 9 and 10.

It is adapted to receive said wheel 5 and receive said motor support 7.

The volute 3 includes in particular:

- an opening 3f (illustrated in Figure 4 and dotted in Figure 1);

an internal wall 30 (illustrated in FIGS. 1 and 3) comprising:

- an air inlet 3c (illustrated in Figure 2);

- a 3d air outlet (illustrated in Figures 1 to 4, and 9 and 10);

- a cut 3g (illustrated in Figures 2, 9 and 10);

- a 3h end part disposed between said cutout 3g and said 3d air outlet (illustrated in FIGS. 9 and 10 and partly in FIGS. 2 and 3).

The engine support 7 is fixed in an opening 3f opposite the air inlet 3c. The motor support 7 delimits a housing for the motor 9. The wheel 5 is disposed around the motor 9 in the volute 3 coaxially with said motor 9.

The internal wall 30 defines an air duct 31 (illustrated in FIGS. 1 and 9) in which the air flow F1 can circulate.

o Air inlet. 3

A first air flow F0, called incoming, illustrated in FIG. 1 is drawn axially into the volute 3 by the air inlet 3c and is put into circulation in said volute 3 to give a second radial air flow F1 which is extracted from volute 3 by the 3d air outlet.

As illustrated in FIG. 2, the air inlet 3c of the volute 3 is defined by an inner circumference 34 of the upper part 3b of the casing of the volute 3. The peripheral crown 17 of the wheel 5 such that illustrated in Figures 9 and 10 is of outer diameter D2.

o 3d air outlet

The 3d air outlet acts as the extraction plenum for the second F1 air flow. It extends from the 3g cut. In a nonlimiting embodiment illustrated in FIG. 2, the 3d air outlet comprises a substantially rectangular section, with two edges 32 and 33 facing each other substantially parallel to one another. The edge 32 is opposite to the cut 3g and the edge 33 is adjacent to the cut 3g.

In a nonlimiting embodiment, the 3d air outlet has a height H1 between 85 to mm and 110mm and a width L1 between 35mm and 65mm.

In a preferred nonlimiting alternative embodiment, said 3d air outlet comprises a height H1 of between 85mm and 104mm.

In a preferred non-limiting alternative embodiment, said 3d air outlet comprises a width L1 of between 56mm and 65mm.

In a very preferred non-limiting variant embodiment, said 3d air outlet comprises a height H1 of between 85mm and 95mm.

In a very preferred non-limiting variant embodiment, said 3d air outlet comprises a width L1 of between 56mm and 62mm.

o Cut, 3g.

The 3g cut, also called volute beak, is called "cutoff" or "tongue" in English.

Cutoff 3g is defined between the start of the radial angular evolution of the internal wall 30 of the volute 3 and the edge 33 of the 3d air outlet. It thus makes the connection between the two. It thus begins at the start of the radial angular evolution and ends at the edge 33 of the 3d air outlet.

In a nonlimiting embodiment illustrated, the cut 3g has a curvature defined by a circle 4 with center C and radius of curvature Rc. It is defined by a cutoff angle 0 _c described below. In a nonlimiting embodiment, said cut 3g is between 9% and 11% of the outside diameter D2 of the wheel 5.

o Final.part. 3h

The 3h terminal part leads to the 3d air outlet.

As illustrated in Figures 9 and 10, it includes:

- a 3h ’rectilinear sub-part adjacent to the end of the radial angular evolution of the internal wall 30;

- a 3h ”straight sub-section adjacent to the end of the 3g cut.

In a nonlimiting embodiment, the two sub-parts 3h ’and 3h” are substantially partly parallel to each other. As we can see, the two 3h ’and 3h’ subparts are not the same length, the 3h ’subpart being larger than the 3h’ subpart.

The internal wall 30 comprises a variable section, generally mathematically determined. Thus, the internal wall 31 evolves according to a radial angular evolution. As illustrated in FIGS. 9 and 10, the volute 3 is for this purpose determined by different characteristics including in particular:

- a development angle a;

- a radius of radial evolution r;

- a cutting angle Oc, also called the volute beak position angle; and

- a cut-off distance i.

These features are described below.

o Development angle.c

The development angle a is illustrated in Figure 9.

It is called in English "expansion angle".

The development angle a is the angle between the internal wall 30 of the volute 3 and the peripheral ring 17 of the wheel 5.

The development angle a is a function of the distance between the internal wall 30 and the peripheral ring 17 of the wheel 5. In a nonlimiting embodiment, this distance varies linearly. Thus, the development of the internal wall 30 takes place at a constant angle of development.

The distance is represented in FIG. 9 by the distances b to i which are the respective distances between the points B to I located on the internal wall of the volute 3 and the peripheral crown 17 of the wheel 5. As can be seen on FIG. 9, apart from point I, an angle of 45 ° (degrees) separates each projection of points B to H on the peripheral ring 17 from at least one other projection on said peripheral ring 17 from an adjacent point. It will be noted that the projections of points B and H have an angle of 45 ° with only a single projection of an adjacent point, namely with the projections of points G and C respectively, while the projections of points C to G have a 45 ° angle with two projections of adjacent points.

Thus, between two projections of two adjacent points, the distance, namely the arc of a circle, on the circle represented by the peripheral crown 17 of the wheel 5 is therefore πϋ2 / 8, namely 0.125π D2. Note that point A represents the full angle, namely the distance πϋ2.

Note that point I is the point at the cut-off angle Oc described below. In a nonlimiting embodiment, the distance from point I is the cut-off distance i described below.

In a nonlimiting embodiment, the development angle a is between 4.7 ° (degrees) and 4.9 ° (degrees).

The development angle a and the diameter D2 of the peripheral crown 17 of the wheel 5, as well as the radius of radial evolution r described below, determine a first radial dimension XX and a second radial dimension YY of the volute 3 illustrated in FIG. 9. The radial dimension YY is perpendicular to the radial dimension XX.

In a nonlimiting embodiment, the first radial dimension X-X is between 175mm and 212mm and the second radial dimension Y-Y is between 195mm and 246mm.

In a preferred non-limiting alternative embodiment, said scroll has a first radial dimension between 186mm and 202mm.

In a preferred non-limiting alternative embodiment, said scroll has a second radial dimension between 228mm and 232mm. In a very preferred non-limiting variant, said scroll has a first radial dimension between 190mm and 202mm.

In a very preferred non-limiting variant, said scroll has a second radial dimension between 229mm and 232mm.

It should be noted that thanks to the characteristics of the development angle a, the electrical power gain as well as the air efficiency are improved. Thus, the gain in electrical power is improved.

Thus, a lower electrical power is provided to ensure identical aeraulic performance or an equivalent electrical power is provided to ensure better aeraulic performance.

o Eyolutipn.radial.r radius

The radius of radial evolution r is illustrated in FIGS. 9 and 10.

The internal wall 30 of the volute 3 evolves according to a radial angular evolution in a radial direction relative to the axis of revolution A. The radial angular evolution begins at the cut 3g, namely at point I illustrated in FIG. 9, and ends at point B illustrated in FIG. 9 which defines the end of the radial angular evolution, point B being located near the exit 3d. Thus, the cut 3g (more particularly the start of the cut 3g) defines a first end I of the radial angular evolution of the volute 3, and the point B defines a second end of the radial angular evolution of the volute 3.

Near the cutout 3g, the radial dimension of the internal wall 30 is smaller than that near the outlet 3d.

After the cut 3g, more particularly at the end of the cut 3g, the internal wall 30 extends via its sub-part 3h "from its end part 3h until the 3d air outlet of the volute 3.

From the second end B, the internal wall 30 extends via its subpart 3h ’from its terminal part 3h until the 3d air outlet of the volute 3.

The internal wall 30 of the volute 3 thus comprises a radius r, called the radius of radial evolution, having a radial angular evolution as a function of an angle of radial evolution Θ so that said internal wall 30 forms a spiral.

The radial evolution angle Θ is taken in a plane perpendicular to the axis of rotation A of the motor-fan unit, namely the axis of revolution A of said route 5. It is called in English "radial evolution angle> >.

The radius r is defined from the axis of revolution A to the internal wall 30 according to the direction of rotation of the wheel 5 and the direction of the second air flow F1 represented by the arrow illustrated in FIG. 10 representing the radial angular evolution of the volute 3. Thus, the radius ra a minimum length at the cut 3g and a maximum length at the end of the radial evolution which is adjacent to the edge 32 of the air outlet 3d opposite to the cut

3g. Note that the terminal portion 3h of the internal wall 30 has been shown in dotted lines for the sake of understanding.

In a nonlimiting embodiment illustrated in FIG. 10, the radial angular evolution is an exponential radial angular evolution conforming to the relation r = τ0θχρ (Ι0π 0/180 °) with:

- 0 the radial evolution angle comprised between a cut-off angle 0 _c and a maximum radial evolution angle 0m;

- rO, the radius of the internal wall 30 for 0 = 0 _c ;

- I0 a constant.

0m corresponds to the end of the radial evolution, in the vicinity of the edge 32 of the 3d air outlet. It corresponds in Figure 10 to the 360 ° angle starting from 0 ° and 360 ° - 0 _c from the start of the radial evolution.

As illustrated in FIG. 10, it will be noted that the start of the radial evolution of the volute 3 is defined by the intersection of a virtual straight line D3 passing through the axis of rotation A of the motor-fan unit the wall internal 30 of said volute 3, and passing through the center C of circle 4 defining the curvature of the cut 3g of said volute 3.

In another nonlimiting embodiment not illustrated, the radial angular evolution is a logarithmic radial angular evolution.

o Cutting angle 0c

The cut-off angle 0c is illustrated in Figure 10.

The cutting angle Oc is called in English "cutoff angle".

It determines the limit where the radial evolution of the volute 3 begins and the start of the cut 3g which is in the vicinity of the edge 33 of the 3d output of the volute 3.

The cut-off angle 0c is defined between the end of the radial evolution of the volute 3 and the start of the radial evolution of the volute 3 as illustrated in FIG. 10. Thus, its origin begins at the end of radial evolution. The end of the radial evolution is represented by 360 ° in Figure 10.

In a nonlimiting embodiment, the cut-off angle Oc is between 45 ° and 65 °. In a preferred non-limiting variant, the cut-off angle Oc is between 52 ° and 59 °. In a very preferred non-limiting variant embodiment, the cut-off angle Oc is between 52 ° and 55 °.

The cutoff angle Oc thus determines a cutoff of the internal wall 30 of the volute 3 as illustrated by the dotted curve in FIG. 10.

The cut-off angle Oc as characterized above also contributes to the reduction of the acoustic level of the motor-fan unit 1 and to the reduction of the electric power used.

o Cut-off distance.i

The cut-off distance i is illustrated in FIG. 9 and FIG. 10.

It corresponds to the distance between the internal wall 30 at the start of the cut 3g (namely at the start of the radial angular evolution) and the peripheral ring 17 of the wheel 5. This corresponds to the distance between the blades of the wheel 5 and the cut 3g, when said wheel 5 includes pale. This distance i is on the virtual line D3 which passes through the center C of the circle 4 defining the curvature of the cut 3g.

In a nonlimiting embodiment, the cutoff distance i is between 8% and 10% of the outside diameter D2 of the wheel 5. In a preferred nonlimiting variant, the cutoff distance is between 9.2% and 10% of the outside diameter of said wheel. In a very preferred non-limiting variant, the cut-off distance is between 9.3% and 9.7% of the outside diameter of said wheel.

Thus, the volute 3 which has at least one of the characteristics as described makes it possible to improve the ventilation efficiency of the fan unit 1, while reducing the acoustic nuisances generated by the rotation of the wheel 5 in the volute 3. The more the group motor fan 1 provides a high air flow, the more savings are made in terms of electrical power.

Furthermore, the volute 3 makes it possible to reduce the necessary mechanical torque supplied by the motor shaft 9a and / or the speed of rotation of said motor shaft 9a while ensuring identical aeraulic performance (that is to say for a pressure and equivalent air volume flow). This reduces the electrical power required to run the engine.

Of course, the description of the invention is not limited to the application and to the embodiments described above.

Thus, in another nonlimiting embodiment, the fan unit 1 is a motor fan group for heating, ventilation and / or air conditioning system for residential or industrial buildings.

Thus, in another nonlimiting embodiment, the development of the internal wall 30 takes place at a variable angle of development.

Thus, the invention described has the following advantages in particular:

- Thanks to the volute 3 thus characterized, the electric power to be supplied to the motor 9 is reduced to put it in rotation, which improves the efficiency of the motor, said efficiency of the motor being equal to the ratio of the mechanical power produced over the electrical power used. This reduces the power consumption of the motor 9;

- thanks to the volute 3 thus characterized, the aeraulic power of the motor-fan unit 1 is increased. The aeraulic efficiency is thus improved;

- thanks to the improved engine efficiency and the ventilation efficiency, the overall efficiency of the motor-fan unit 1 is improved, the overall efficiency being equal to the efficiency of the engine multiplied by the ventilation efficiency. In other words, the overall efficiency is equal to the ratio of the electrical power consumed over the generated aeraulic power;

thanks to the volute 3 thus characterized, to obtain a ventilation efficiency identical to the prior art, the mechanical power is improved thanks to a reduction in the mechanical torque delivered by the motor shaft 9a and / or a reduction in the speed of rotation of said engine shaft

9a. The reduction in mechanical torque makes it possible to reduce the electrical consumption of the motor 9. The reduction in the speed of rotation of said motor shaft 9a makes it possible to reduce the acoustic level 5 of the motor-fan unit 1.

Claims (10)

1. Motor-fan unit (î) comprising a wheel (5) and a volute (3) adapted to be mounted on a heating / ventilation and / or air conditioning (HVAC) system for a motor vehicle, - said wheel (5) comprising: - a hub (15) adapted to be mounted on a drive shaft (9a) J - a peripheral crown (17) provided with a succession of blades (19), said hub (15) and the peripheral crown (17) being connected to one another; - said volute (3) comprising: - an internal wall (30) adapted to evolve in part according to a radial angular evolution; - an air inlet (3c) and an air outlet (3d); and being adapted to receive said wheel (5), said wheel (5) being adapted to be arranged in said volute (3) coaxially around a motor (9) of said motor-fan unit (1); characterized in that: - Said wheel (5) comprises at least one blade whose angle of attack (β1) is between 67 ° and 79 °; - The ratio between the inside diameter (D1) and the outside diameter (D2) of the wheel is between 75% and 85%; and - said volute (3) comprises a development angle (a) of between 4.7 ° and 4.9 °, said development angle (a) being the angle between said internal wall (30) of said volute (3) and said peripheral crown (17) of said wheel (5). 2. Motor-fan unit (1) according to claim 1, characterized in that said wheel (5) has a height (H) between 60 mm and 90 mm, and preferably between 65 and 85 mm. 3. motor-fan unit (1) according to claim 1 or claim 2, characterized in that said wheel (5) comprises at least one blade whose leakage angle (β2) is between 155 ° and 167 °. 4. motor-fan unit (1) according to any one of claims 1 to 3, characterized in that the ratio between the inside diameter (Dl) and the outside diameter (D2) of the wheel is between 78.3% and 80.3%. 5. fan motor unit (1) according to any one of claims 1 to 4, characterized in that the angle of attack (β1) is between 70 ° and 76 °. 6. fan motor unit (1) according to any one of claims 1 to 5, characterized in that said wheel comprises at least one blade (19) which has a thickness (e) between 0.8 mm and 2.1 mm. 7. fan motor unit (1) according to any one of claims 1 to 6, characterized in that said volute (3) comprises a cut (3g) defined between a start of the radial angular evolution of said volute (3 ) and an edge (33) of said air outlet (3d), said cutoff (3g) being defined by a cutoff angle (Oc) of between 45 ° and 65 °. 8. motor-fan unit (1) according to claim 7, characterized in that said cutoff (3g) is between 9% and 11% of the outside diameter (D2) of said wheel (5). 9. fan motor unit (1) according to claim 7 or 8, characterized in that said volute (3) comprises a cut-off distance (i) between 8% and 10% of the outside diameter (D2) of said wheel ( 5). 10. fan motor unit (1) according to any one of claims 1 to 9, characterized in that said wheel (5) has an outside diameter (D2) between 130mm and 165mm.