ELECTRIC FAN

Abstract

 The invention relates to an electric fan capable of generating a pressure differential between a first zone, named upper pressure zone (44), and a second zone, named lower pressure zone (43), the pressure of said upper pressure zone (44) being greater than the pressure of said lower pressure zone (43), said fan comprising:
- a casing (29) having a wall delimiting an internal space of the casing (29), said casing (29) being disposed in said upper pressure zone (44);
- an electronic device, said electronic device being disposed in said internal space of the casing (29),
characterised in that it comprises at least one duct, named aeration duct (35), outside said casing (29) and comprising a first opening disposed in said upper pressure zone (44) in the vicinity of an outer face of the wall of said casing (29) and a second opening disposed in said lower pressure zone (43).

Description

[0001] The invention relates to an electric fan.

[0002] A fan generally comprises:

• a stator;
• a ventilation rotor rotationally mounted relative to the stator;
• a device for driving the ventilation rotor comprising:

  ∘ an electric motor adapted to be able to rotate the ventilation rotor relative to the stator;

  ∘ a casing having a wall delimiting an internal space of the casing;

  ∘ an electronic device for controlling the motor, said electronic device being disposed in said internal space of the casing.

[0003] It is known that rotating the ventilation rotor relative to the stator by means of said motor is limited by a maximum permissible temperature for the electronic components of said electronic device for controlling the motor. Furthermore, exceeding this maximum temperature can lead to a reduction in the lifetime of said electronic device. Moreover, the air flow diffused by the rotation of the ventilation rotor does not allow said electronic device to be sufficiently cooled.

[0004] Numerous electric fans are thus known that comprise means for cooling said electronic device so that the temperature of the electronic components during the operation of the electric fan is less than the maximum permissible temperature for these electronic components.

[0005] For example, document FR 2921446 discloses an electric fan comprising an electric motor located in a motor casing. This electric motor is adapted to rotate a fan. A depression zone, named low-pressure zone, is established by rotating the fan. Furthermore, the electric fan comprises an electronic board for controlling the electric motor and a radiator delimiting a motor zone between an upper face of the radiator and the motor casing, and a board zone between a lower face of the radiator and a cover. Said electronic board is disposed in the board zone. The electric fan comprises at least one opening connecting the low-pressure zone to the motor zone. Furthermore, the radiator comprises at least one opening between the motor zone and the board zone. The cover comprises a secondary air inlet between the board zone and an outer zone of said cover, the pressure of said outer zone being greater than the pressure in the low-pressure zone. The pressure differential between said outer zone and the low-pressure zone generates a secondary air flow circulating from the secondary air inlet to the low-pressure zone by passing through the various openings due to the pressure differences between the outer zone, the board zone, the motor zone and the low-pressure zone. This secondary air flow thus cools the electronic board.

[0006] Thus, in such an electric fan, the means for cooling the electronic board for controlling the motor are formed by a plurality of openings arranged through the motor casing, a radiator and a cover covering the electronic board. Such an electric fan thus has a relatively complex structure. Furthermore, manufacturing such an electric fan is time-consuming and expensive.

[0007] The invention aims to overcome these disadvantages.

[0008] Therefore, the aim of the invention is to propose an electric fan comprising means for cooling an electronic device of this electric fan, said cooling means having a simple structure.

[0009] The invention also aims to propose such an electric fan having inexpensive cooling means.

[0010] A further aim of the invention is to propose such an electric fan having simple to manufacture cooling means.

[0011] Therefore, the invention relates to an electric fan capable of generating, during its operation, a pressure differential between a first zone, named upper pressure zone, and a second zone, named lower pressure zone, the pressure of said upper pressure zone being greater than the pressure of said lower pressure zone, said fan comprising:

• a casing having a wall delimiting an internal space of the casing, said casing being disposed in said upper pressure zone;
• an electronic device, said electronic device being disposed in said internal space of the casing,

characterised in that it comprises at least one duct, named aeration duct, outside said casing and comprising at least one opening, named first opening, disposed in said upper pressure zone in the vicinity of an outer face of the wall of said casing and at least one opening, named second opening, disposed in said lower pressure zone.

[0012] Thus, each aeration duct forms a passage connecting said upper pressure zone to said lower pressure zone.

[0013] When the fan is turned on, the fan generates an air flow, named ventilated air flow, by sucking in air at an inlet of the fan. The ventilated air is then diffused at an outlet of the fan towards the outside of the fan. Sucking in the air at the inlet of the fan and diffusing the suction air at the outlet of the fan generates the pressure differential between said lower pressure zone, at the inlet of the fan, and said upper pressure zone, at the outlet of the fan.

[0014] The pressure differential between said lower pressure zone and said upper pressure zone when the fan is turned on, and the fact that each aeration duct connects said lower pressure zone and said upper pressure zone, allow an air flow, named cooling air flow, to be generated along an outer face of the wall of the casing, then through each aeration duct. Then, the pressure difference between said upper pressure zone and said lower pressure zone generates a cooling air flow from said upper pressure zone that passes through each aeration duct towards said lower pressure zone.

[0015] In particular, the electronic device is adapted to control the operation of the fan.

[0016] The electronic device comprises a plurality of electronic components, particularly power electronics components, for example for powering said motor. These electronic components are preferably mounted on an electronic board. The temperature of these electronic components must be less than a maximum temperature in order to ensure the correct operation of these electronic components and to avoid reducing their lifetime. The cooling air flow generated by an electric fan according to the invention cools the electronic components of the electronic device to be cooled so that their temperature is permanently below said maximum temperature during the rotation of the fan. More specifically, the cooling air flow circulating along said outer face of the wall of the casing reduces the temperature in the internal space of the casing in order to also cool the electronic device.

[0017] Each aeration duct thus forms means for cooling the electronic device that have a simple structure and are inexpensive and simple to manufacture.

[0018] With an electric fan according to the invention, the casing does not need to be adapted in any way in order to generate a cooling air flow for cooling the electronic device.

[0019] The shape of the casing is adapted to cover said electronic device. In some advantageous embodiments, and according to the invention, the wall of the casing forms cooling fins in order to improve the cooling of the electronic device.

[0020] However, nothing precludes the provision of other cooling means in addition to each cooling air flow obtained using each aeration duct. Therefore, the drive device can comprise a plurality of openings, particularly through the casing, allowing an air flow passage to be obtained in the internal space of the casing along the electronic device.

[0021] A fan according to the invention can be used in multiple applications such as air handling unit, heat pumps, ventilation units and filter units.

[0022] In some embodiments, the fan comprises:

• a stator;
• a ventilation rotor rotationally mounted relative to the stator, said ventilation rotor being capable of generating a pressure differential between a first zone, named upper pressure zone, and a second zone, named lower pressure zone, the pressure of said upper pressure zone being greater than the pressure of said lower pressure zone;
• a device for driving the ventilation rotor comprising:

  ∘ an electric motor adapted to be able to rotate the ventilation rotor relative to the stator;

  ∘ said casing; and

  ∘ said electronic device.

[0023] Turning on the motor allows the ventilation rotor to be rotated. Rotating the ventilation rotor generates the pressure differential between said lower pressure zone located at an inlet of the ventilation rotor and said upper pressure zone located at an outlet of the ventilation rotor.

[0024] The ventilation rotor is adapted to be rotated about an axis, named main axis.

[0025] Said lower pressure zone and said upper pressure zone are distributed opposite each other relative to a plane transverse to the ventilation rotor and perpendicular to the main axis of said rotor.

[0026] The electronic device is adapted to control the motor.

[0027] In some embodiments, the motor is a motor of the brushless type, i.e. a permanent magnet electric motor. Alternatively, the motor can be a permanent magnet DC motor, an induction motor, a switched reluctance motor or a universal AC-DC motor for example.

[0028] The motor comprises a rotor, named drive rotor, capable of being rotated about the main axis of the ventilation rotor. Furthermore, the ventilation rotor is rotationally coupled to the drive rotor of the motor in order to be able to be rotated about said main axis by the drive rotor.

[0029] Each aeration duct extends outside the drive device, particularly outside the casing and the motor.

[0030] Each aeration duct can be of any shape. Thus, each aeration duct can have, for example, a circular, square, rectangular or even hexagonal transverse section.

[0031] In some advantageous embodiments, at least one aeration duct is defined in a hollow tube with a circular transverse section.

[0032] In some advantageous embodiments, and according to the invention, the ventilation rotor comprises a plurality of vanes.

[0033] In particular, in some embodiments, and according to the invention, the fan is a radial fan. The fan rotor then has a central chamber around the main axis and the vanes are disposed around this central chamber. Furthermore, the ventilation rotor has an opening extending orthogonal to said main axis and forming an air inlet in order for air to be introduced into the central chamber of the ventilation rotor, between the radial vanes. The radial vanes then radially diffuse this air towards the outside of the ventilation rotor.

[0034] Alternatively, the fan can be an axial fan. The ventilation rotor then has vanes extending from the main axis and orthogonal to the main axis of the ventilation rotor.

[0035] In some preferred embodiments, and according to the invention, the stator comprises a chassis supporting the ventilation rotor and at least one aeration duct is arranged inside the chassis of the stator.

[0036] In particular, the chassis supports the casing, the electronic device, the motor and the ventilation rotor. Therefore, the chassis not only supports the aforementioned elements of the electric fan but also receives said aeration duct for cooling the electronic device.

[0037] However, nothing precludes the provision of an aeration duct that is distinct from the chassis and that is not used to support the various elements of the electric fan.

[0038] In some advantageous embodiments, the stator comprises a chassis supporting the ventilation rotor and the drive device, said chassis comprising:

• a main support disposed in said lower pressure zone;
• at least one arm rigidly connected to said casing and said main support.

[0039] In particular, the main support comprises a main opening coaxial to the ventilation rotor. This main opening allows air to access to the central chamber of the ventilation rotor when it is rotated.

[0040] In some advantageous embodiments, the main support forms a platform.

[0041] In some advantageous embodiments, and according to the invention, at least one duct is formed by an arm of the chassis.

[0042] Thus, each arm forming an aeration duct holds the ventilation rotor and the drive device and also generates a cooling air flow to cool said electronic device.

[0043] In some advantageous embodiments, at least one arm of the stator forming an aeration duct is of hollow tubular shape, the hollow of this arm defining an aeration duct.

[0044] In some advantageous embodiments, the chassis comprises a ring, named guide ring, coaxial to the main opening of the ventilation rotor and disposed between said main support and the ventilation rotor.

[0045] When the ventilation rotor is a radial rotor, the guide ring is partly inserted into the ventilation rotor. Thus, the guide ring holds the ventilation rotor radially and axially. Furthermore, the guide ring and the main support can be formed by two different parts or even can be a single piece.

[0046] In some advantageous embodiments, and according to the invention, the chassis comprises a secondary support disposed in said upper pressure zone and rigidly assembled to the casing and to each arm of the chassis.

[0047] More specifically, said secondary support is assembled to said casing of the device for driving the ventilation rotor. Thus, the arms of the chassis are rigidly connected to the casing by means of the secondary support.

[0048] Furthermore, in some advantageous embodiments the secondary support has an opening, through which said device for driving the ventilation rotor passes so that the casing can be disposed on a first side of said secondary support and so that the motor can be disposed on a second side of said secondary support, the motor thus being able to be assembled to the ventilation rotor.

[0049] In some advantageous embodiments, and according to the invention, said main support comprises at least one opening, named secondary opening, and each aeration duct formed in an arm of the stator has an end emerging onto a secondary opening of the main support.

[0050] Thus, each duct has an end emerging onto said lower pressure zone by means of a secondary opening of the main support.

[0051] In some advantageous embodiments, and according to the invention, each arm comprising an aeration duct comprises an opening, named air inlet opening, emerging into said upper pressure zone.

[0052] This inlet opening allows an air flow to access the duct formed in the arm in order to be guided towards said lower pressure zone.

[0053] In some advantageous embodiments, and according to the invention, at least one arm comprising a duct is in the shape of an arch, said duct extending from a first end of the arm to a second end of the arm, said first end and said second end of the arm being assembled to the main support, part of the arm having said air inlet opening being assembled to said secondary support.

[0054] Thus, the air inlet opening is disposed in the vicinity of the casing.

[0055] In some advantageous embodiments, and according to the invention, the electric fan comprises at least one air guide mounted on an outer face of the wall of said casing, said air guide forming, with the casing, a passage along part of the outer face of the wall of said casing between a first opening at a first end of the air guide and a second opening at a second end of the air guide, the second opening being disposed facing the air inlet opening of an arm comprising an aeration duct.

[0056] The air guide is thus arranged to direct the cooling air flow along the wall of the casing from the first opening of the air guide to the air inlet opening of an arm comprising an aeration duct. This aeration duct is then formed by this arm and by the air guide. In particular, the first opening of the air guide forms said first opening of the aeration duct and the second end of the arm forms said second opening of the aeration duct.

[0057] Furthermore, in some embodiments, the air guide is a detachable part relative to the arm having the air inlet opening facing the second opening of the air guide. The use of a detachable air guide facilitates the assembly of the drive device to said secondary support of the chassis. However, alternatively, the air guide can be assembled in a non-detachable manner relative to the arm. In other embodiments, the air guide and the arm are formed as a single piece.

[0058] The invention further relates to an electric fan that is characterised, in combination or separately, by all or some of the features specified above or hereafter. Irrespective of the formal presentation that is provided, unless explicitly stated otherwise, the various features specified above or hereafter must not be considered to be closely or inextricably linked to each other, the invention can relate to only one of these structural or functional features, or to only some of these structural or functional features, or to only part of one of these structural or functional features, or even to any group, combination or juxtaposition of all or some of these structural or functional features.

[0059] Further aims, features and advantages of the invention will become apparent upon reading the following description, which is provided by way of a non-limiting example of some of its possible embodiments, and with reference to the accompanying drawings, in which:

• figure 1 is a perspective view of an electric fan according to one embodiment of the invention;
• figure 2 is a further perspective view of the electric fan of figure 1;
• figure 3 is a perspective and exploded view of the electric fan of figure 1;
• figure 4 is a view of the electric fan along a section A-A shown in figure 1;
• figure 5 is a perspective view of an electric fan according to another embodiment of the invention.

[0060] An electric fan 10 according to the embodiments shown in the figures comprises a stator 11, a ventilation rotor 12 and a device 26 for rotating the ventilation rotor 12 about an axis, named main axis 13.

[0061] The fan 1 can be a radial fan, as shown in figures 1 to 4, or an axial fan, as shown in figure 5.

[0062] When the fan 10 is a radial fan, the ventilation rotor 12 comprises two coaxial rings 14, 15 along said main axis 13. A central chamber of the ventilation rotor 12 is defined between the coaxial rings 14, 15. Furthermore, the rotor comprises a plurality of vanes 16 extending around the central chamber between the two rings 14, 15. A first ring, named lower ring 14, has a central circular opening, named suction opening 24, centred on the main axis 13. A second ring, named upper ring 15, has an opening, named assembly opening 25.

[0063] When the fan 10 is an axial fan, the ventilation rotor 12 comprises a shaft 17 centred along the main axis 13 of the ventilation rotor 12 and the vanes 16 extend radially from the shaft 17 of the rotor.

[0064] The stator 11 comprises a chassis 18 comprising a main support 19 forming a platform and comprising an opening, named main opening 20, coaxial to the ventilation rotor 12. The stator 11 further comprises a guide ring 21 rigidly assembled to the main support 19 and centred on said main axis 13. More specifically, the guide ring 21 has a base 22 rigidly assembled to the main support 19 and defining a first opening disposed facing the main opening 20 of the main support 19. Preferably, said base 22 is assembled to the main support 19 by a screw/nut system.

[0065] Furthermore, the guide ring 21 has a rotationally cylindrical portion 23 around said main axis 13. This rotationally cylindrical portion 23 passes through the suction opening 24 of the ventilation rotor 12 and is adapted to axially and radially hold the ventilation rotor 12 when the fan is a radial fan. When the fan 10 is an axial fan, the ventilation rotor 12 is disposed in the rotationally cylindrical portion 23 of the guide ring 21.

[0066] The drive device 26 comprises a motor 27, particularly a motor 27 of the brushless type. Alternatively, the motor can be a permanent magnet DC motor, an induction motor, a switched reluctance motor or a universal AC-DC motor for example. In particular, the motor 27 comprises a rotor, named drive rotor 28, extending along said main axis 13 and being rotationally coupled around said main axis 13 of said ventilation rotor 12.

[0067] The motor 27 is adapted to rotate said drive rotor 28 about said main axis 13 in order to rotate said ventilation rotor 12 about the main axis 13. To this end, the upper ring 15 of the ventilation rotor 12 is assembled to the drive rotor 28 of the motor 27 passing through said assembly opening 25. Preferably, the upper ring 15 of the ventilation rotor 12 is assembled to the drive rotor 28 by a screw/nut system.

[0068] The drive device 26 further comprises a casing 29 assembled to the motor 27 and having a wall delimiting an internal space of the casing 29. Furthermore, the wall of the casing 29 forms a plurality of cooling fins 30.

[0069] The drive device 26 further comprises an electronic device (not shown) disposed in said internal space of the casing 29. Said electronic device controls the motor 27, particularly the speed of rotation of the drive rotor 28. The electronic device comprises a plurality of electronic components, particularly power electronics components. These electronic components are particularly used to power the motor 27. The electronic components are preferably mounted on an electronic board. Furthermore, the electronic device is adapted to receive a power supply voltage through a power supply source outside the fan 10.

[0070] When the motor 27 is turned on by the electronic device to rotate the ventilation rotor 12, the rotation of the ventilation rotor 12 generates an air flow, named ventilated air flow, from the inlet of the ventilation rotor 12 and which is diffused by the vanes of the ventilation rotor 12 towards the outside of the fan 10. In particular, air is sucked through the main opening 20 of the main support 19, then passes through the guide ring 21 to reach the ventilation rotor 12 through the suction opening 24 of the lower ring 14. The air is then diffused towards the outside of the fan 10 by the vanes of the ventilation rotor 12.

[0071] Sucking in air at the inlet of the ventilation rotor 12 and diffusing the suction air at the outlet of the ventilation rotor 12 generates a pressure differential between a zone, named lower pressure zone 43, located at the inlet of the ventilation rotor 12 and a zone, named upper pressure zone 44, located at the outlet of the ventilation rotor 12. The pressure of said lower pressure zone 43 is then lower than the pressure of said upper pressure zone 44.

[0072] In particular, the casing 29 is disposed downstream of the ventilated air flow and, for this reason, in the upper pressure zone 44.

[0073] Furthermore, the chassis 18 comprises a secondary support 31 in the form of a plate having an opening 32, through which said drive device 26 passes. The secondary support 31 is rigidly assembled to the casing 29 of the drive device 26, particularly by a screw/nut system.

[0074] Furthermore, the chassis 18 comprises a plurality of arms 33 assembled to the secondary support 31 and to the main support 19 in order to rigidly hold the secondary support 31. Thus, the secondary support 31 and the arms 33 allow the drive device 26 and the ventilation rotor 12 to be supported.

[0075] More specifically, the chassis 18 comprises two arms 33a, 33b, each arm 33a, 33b being an arch having two ends 37a, 37b assembled to the main support 19 of the chassis 18. The two arms 33a, 33b are assembled to the same face of the secondary support 31 and are opposite each other.

[0076] Each arm 33a, 33b comprises a wall of hollow tubular shape. The arm 33a comprises an opening, named air inlet opening 34, through the wall of this arm 33a so as to connect the hollow internal part of the arm 33a with the outside. This hollow internal part then forms a duct, named aeration duct 35, extending between the two ends 37a, 37b of this arm 33a. In particular, the air inlet opening 34 of the arm 33a emerges into said upper pressure zone 44. Part of the arm 33a having said air inlet opening 34 is assembled to said secondary support 31.

[0077] The aeration duct 35 can be of any shape. Thus, each aeration duct 35 can have, for example, a circular, square, rectangular or even hexagonal transverse section.

[0078] Furthermore, the main support 19 comprises two openings, named secondary openings 38, and each end 37a, 37b of the arm 33a comprising said aeration duct 35 is assembled to the main support 19 so that each end of the aeration duct 35 emerges onto a respective secondary opening 38.

[0079] Thus, each end of the duct emerges onto said lower pressure zone 43 by means of a secondary opening 38 of the main support 19.

[0080] The aeration duct 35 therefore has two branches 36a, 36b, a first branch 36a between said air inlet opening 34 and a first end of the duct and a second branch 36b between said air inlet opening 34 and a second end of the aeration duct 35.

[0081] The electric fan 10 further comprises an air guide 39 mounted on an outer face of the wall of said casing 29. Said air guide 39 has a wall forming a passage 40 with the wall of the casing 29. In particular, the wall of the air guide 39 and the wall of the casing 29 form the passage 40 between a first opening 41 formed by the air guide 39 and the casing 29 up to a second opening 42 formed by the wall of the air guide 39 and disposed facing the air inlet opening 34 of an arm 33a comprising an aeration duct 35. Thus, the air guide can guide an air flow in the passage 40 along the wall of the casing 29 between said first opening 41 and said second opening 42.

[0082] The air guide 39 is thus arranged to direct the air flow along the wall of the casing 29 up to the air inlet opening 34 of the arm 33a comprising an aeration duct.

[0083] Preferably, as shown in figure 1, the air guide 39 is a detachable part relative to the arm 33a having the air inlet opening 34 facing the second opening 42 of the air guide 39. In particular, the air guide 39 is mounted on the arm 33a by resilient interlocking. The use of a detachable air guide 39 facilitates the assembly of the drive device 26 to said secondary support 31 of the chassis 18. However, alternatively, the air guide 39 can be assembled in a non-detachable manner relative to the arm 33a. Alternatively, the air guide 39 and the arm 33a can be formed as a single piece.

[0084] The aeration duct, by connecting said lower pressure zone 43 and said upper pressure zone 44 and the pressure differential between said lower pressure zone 43 and said upper pressure zone 44 when the motor 27 is turned on, generates an air flow, named cooling air flow, through the duct from said upper pressure zone 44 to said lower pressure zone 43.

[0085] In particular, the cooling air flow initially circulates along the outer face of the wall of the casing 29, particularly along cooling fins 30, before reaching said first opening 41 of the air guide 39 placed on the wall of the casing 29. The air guide 39 then transfers, through its second opening 42, the cooling air flow to the aeration duct 35 through the air inlet opening 34 of the arm 33a comprising the aeration duct. The cooling air flow is then routed by the aeration duct 35 to the lower pressure zone 43.

[0086] The cooling air flow by circulating along the outer face of the wall of the casing 29, particularly between the cooling fins 30, reduces the temperature in the internal space of the casing 29 and consequently cools said electronic device.

[0087] The invention can be the subject of numerous variations and applications other than those described above. In particular, it is obvious that, unless otherwise specified, the various structural and functional features of each of the aforementioned embodiments must not be considered to be combined and/or closely and/or inextricably linked to one another, but, on the contrary, must be considered to be simple juxtapositions. Furthermore, the structural and/or functional features of the various embodiments described above can be the subject, in whole or in part, of any different juxtaposition or of any different combination. For example, nothing precludes the provision of other cooling means in addition to each cooling air flow obtained using each aeration duct 35. Thus, the drive device 26 can comprise a plurality of openings, particularly through the casing 29, allowing an air flow passage to be obtained in the internal space of the casing 29 along the electronic device.

[0088] A fan according to the invention can be used in multiple applications such as air handling unit, heat pumps, ventilation units and filter units.

Claims

1. Electric fan capable of generating a pressure differential between a first zone, named upper pressure zone (44), and a second zone, named lower pressure zone (43), the pressure of said upper pressure zone (44) being greater than the pressure of said lower pressure zone (43), said fan comprising:

- a casing (29) having a wall delimiting an internal space of the casing (29), said casing (29) being disposed in said upper pressure zone (44);

- an electronic device, said electronic device being disposed in said internal space of the casing (29),

characterised in that it comprises at least one duct, named aeration duct (35), outside said casing (29) and comprising at least one opening, named first opening, disposed in said upper pressure zone (44) in the vicinity of an outer face of the wall of said casing (29) and at least one opening, named second opening, disposed in said lower pressure zone (43).

2. Fan according to claim 1, characterised in that it comprises:

- a stator (11);

- a ventilation rotor (12) rotationally mounted relative to the stator (11), said ventilation rotor (12) being capable of generating a pressure differential between a first zone, named upper pressure zone (44), and a second zone, named lower pressure zone (43), the pressure of said upper pressure zone (44) being greater than the pressure of said lower pressure zone (43);

- a device (26) for driving the ventilation rotor (12) comprising:

∘ an electric motor (27) adapted to be able to rotate the ventilation rotor (12) relative to the stator (11);

∘ said casing (29); and

∘ said electronic device.

3. Fan according to claim 2, characterised in that the ventilation rotor (12) comprises a plurality of vanes.

4. Fan according to either claim 2 or claim 3, characterised in that the stator (11) comprises a chassis (18) supporting the ventilation rotor (12) and the drive device (26) and comprising:

- a main support (19) disposed in said lower pressure zone (43);

- at least one arm (33a, 33b) rigidly connected to said casing (29) and said main support (19).

5. Fan according to claim 4, characterised in that at least one duct is formed by an arm (33a) of the chassis (11).

6. Fan according to any of claims 2 to 5, characterised in that the stator (11) comprises a chassis (18) supporting the ventilation rotor (12) and in that at least one aeration duct (35) is arranged inside the chassis (18) of the stator (11).

7. Fan according to either claim 4 or claim 5, characterised in that the main support comprises a main opening (20) coaxial to the ventilation rotor.

8. Fan according to claim 7, characterised in that the chassis (18) comprises a ring, named guide ring (21), coaxial to the main opening (20) of the ventilation rotor (12) and disposed between said main support (19) and the ventilation rotor (12).

9. Fan according to any of claims 4 to 8, characterised in that the chassis (18) comprises a secondary support (31) disposed in said upper pressure zone (44) and rigidly assembled to the casing (29) and to each arm (33a, 33b) of the chassis.

10. Fan according to any of claims 4 to 9, characterised in that said main support (19) comprises at least one opening, named secondary opening, and in that each aeration duct (35) formed in an arm (33a) of the stator (11) has an end emerging onto a secondary opening of the main support (19).

11. Fan according to any of claims 5 to 10, characterised in that each arm (33a) comprising an aeration duct (35) comprises an opening, named air inlet opening (34), emerging into said upper pressure zone (44).

12. Fan according to claim 11, characterised in that at least one arm (33a) comprising a duct is in the shape of an arch, said duct extending from a first end of the arm (33a) to a second end of the arm (33a), said first end and said second end of the arm (33a) being assembled to the main support (19), part of the arm (33a) having said air inlet opening (34) being assembled to said secondary support (31).

13. Fan according to either claim 11 or claim 12, characterised in that it comprises at least one air guide (39) mounted on an outer face of the wall of said casing (29), said air guide (39) being arranged to guide an air flow along a portion of the outer face of the wall of said casing (29) up to an opening of the air guide (39) forming, with the casing (29), a passage along part of the outer face of the wall of said casing (29) between a first opening at a first end of the air guide and a second opening at a second end of the air guide, the second opening being disposed facing the air inlet opening (34) of an arm (33a) comprising an aeration duct (35).

Drawing