Motor-fan unit, in particular for a motor vehicle

Abstract

The invention relates to a motor-fan unit, in particular for a motor vehicle, comprising a fan wheel, a drive motor (5) for driving the fan wheel (3), a motor support (7) comprising at least one base (71) and a bearing holder (13) made at least in part from a plastic material, the base (71) comprising an opening (72) through which there pass, at least partially, a rotor shaft of the drive motor (5) and the bearing holder (13) that defines at least one housing (17) receiving at least one bearing (9B) mounted around the rotor shaft. According to the invention, the motor-fan unit comprises at least one sealing element (18) arranged between the base (71) and the bearing (9B), and the housing (17) defined by the bearing holder (13) facing the base (71), the sealing element (18) having the rotor shaft passing at least partially through it.

Description

Description Title of the invention: Motor-fan unit, particularly for a motor vehicle Technical field

[0001] The invention relates to a motor-fan unit or ventilation device which may be intended for the field of vehicles, in particular motor vehicles. The invention relates more particularly to a motor-fan unit. The invention may be applied, for example, to heating, ventilation and / or air conditioning installations for vehicles, in particular motor vehicles, and comprising such a motor-fan unit. Technical background

[0002] Vehicles, particularly motor vehicles, are commonly equipped with a system, for example heating, ventilation and / or air conditioning, which creates an airflow in the passenger compartment. Such a system also makes it possible to manage the temperature and distribution of the airflow created within the passenger compartment. Such a system includes, among other things, a fan, particularly a blower type, comprising a fan wheel rotated by a drive motor, particularly an electric motor. The electric motor may in particular be electronically commutated, controlled by a control module.

[0003] An electronically commutated electric motor, or brushless direct current motor (also known as "brushless"), comprises a rotor and stator assembly, each of these components carrying electromagnetic elements whose interaction generates the movement of the rotor relative to the stator, and thus the movement of the fan wheel.

[0004] The electric motor is mounted in the system, for example heating, ventilation and / or air conditioning, via a motor support.

[0005] According to one solution, the motor support comprises a base or a structure, generally annular, allowing the fixing of the electric motor, more precisely the stator, and generally carrying a control module to drive the motor.

[0006] The engine support further comprises a bearing holder fixed to the structure or the base, and forming a support for at least one, for example two, bearings. For this purpose, the bearing holder has housings in which the corresponding bearings are positioned.

[0007] Bearings are typically tightly mounted around the motor rotor shaft. The rotor shaft and inner rings are therefore rotationally fixed, while the outer rings are slidingly mounted in the corresponding housings. These housings are traditionally cylindrical in shape with a smooth internal surface.

[0008] However, when the engine is running, such an assembly generates friction that can be amplified at the contact areas of the bearing holder with the outer rings. This is problematic when the bearing holder is made of plastic material, which is more fragile than a metal bearing holder, made of aluminum for example. The stresses generated when inserting the bearings over the entire internal surface of the housings can cause cracks and this further weakens the bearing holder. This can result in premature wear of the contact areas of the bearing holder with the bearings, when the bearing holder is made of plastic material.

[0009] Another problem is managing the sealing between the bearing holder and the base carrying the control module.

[0010] An objective of the present invention is to at least partially resolve the drawbacks described above, by securing the insertion of the bearing(s) into the corresponding housings of the bearing holder while guaranteeing the sealing function. Summary of the invention

[0011] To this end, the invention relates to a motor-fan unit, in particular for a motor vehicle, the motor-fan unit comprising: a fan wheel, a motor for driving the fan wheel, a motor support comprising at least one base and a bearing holder made at least partly of plastic material, the base comprising an opening crossed at least partly by a rotor shaft of the drive motor and the bearing holder defining at least one housing receiving at least one bearing mounted around the rotor shaft.

[0012] According to the invention, the motor-fan unit comprises at least one sealing element arranged between, on the one hand, the base and, on the other hand, the bearing and the housing defined by the bearing holder opposite the base, the sealing element being crossed at least in part by the rotor shaft.

[0013] The sealing element is compressed between the base on the one hand and the bearing and the housing defined by the bearing holder on the other hand.

[0014] This sealing element ensures a seal between the bearing holder and the base, and prevents the passage of liquid or air from below the fan wheel to a control module, for example mounted on the base.

[0015] The motor-fan unit may further include one or more of the following characteristics described below, taken separately or in combination.

[0016] The drive motor is notably a brushless motor.

[0017] The at least one housing comprises, for example, an internal wall having an alternation of at least one radial support relief shaped to establish contact with the bearing and at least one hollow between the internal wall of the housing and the bearing. The sealing element may be arranged opposite the at least one hollow.

[0018] The at least one radial support relief can be produced by a rib.

[0019] The at least one housing has, for example, at least one stress relief zone spaced from the bearing received in the housing. The sealing element may be arranged opposite the space between the at least one stress relief zone and the bearing.

[0020] The stress relief zone may exhibit deformation and / or reduced thickness relative to the rest of the housing.

[0021] According to one embodiment, the sealing element has a primary portion and an extension extending from the primary portion.

[0022] The primary part can be arranged between the base on the one hand and the bearing and the housing defined by the bearing holder on the other hand.

[0023] The extension may conform to an internal contour of the base defining the opening through which the rotor shaft passes at least in part. For example, the extension has a collar or ring shape.

[0024] The primary part of the sealing element has, for example, a shape combined with the shape of the housing receiving the bearing opposite the base, and at least one stress relief zone of said housing.

[0025] The primary part may have an openwork shape, for example in its center.

[0026] According to a particular example, at least one stress relief zone has a semicircular shape. The primary part of the sealing element may have at least one portion such as an ear of a shape complementary to the semicircular shape of the stress relief zone.

[0027] The bearing carrier defines, for example, at least a first housing and a second housing. The second housing may be arranged opposite the base.

[0028] At least one first bearing and one second bearing, corresponding, can be mounted respectively in the first housing and in the second housing, around the rotor shaft.

[0029] The sealing element can be arranged between the base on the one hand and the second bearing and the second housing defined by the bearing holder on the other hand.

[0030] The bearing carrier may include a base defining the second housing. The sealing element may be arranged between the base and the base of the bearing carrier.

[0031] The bearing holder may comprise a tubular tower around a central axis of the bearing holder, extending axially from the base and terminating in the first housing opposite the second housing along the central axis.

[0032] The at least one bearing may comprise a respective inner ring and an outer ring, the outer ring being press-fitted in the housing.

[0033] The rotor shaft can be mounted free inside the inner rings of the bearings.

[0034] The motor-fan unit comprises, for example, at least one mechanical fixing member between the base and the bearing holder, for example the base of the bearing holder. The sealing element may be arranged around the mechanical fixing member.

[0035] The base comprises, for example, at least one fixing point. The sealing element can be arranged around the fixing point.

[0036] The sealing element can be secured to the base by overmolding.

[0037] The sealing element is, for example, made of an elastomeric material, in particular polystyrene-b-poly(ethylene-butylene)-b-polystyrene.

[0038] The motor-fan unit may be intended for a heating, ventilation and / or air conditioning installation of a vehicle, particularly an automobile. Brief description of the drawings

[0039] Other advantages and characteristics of the invention will appear more clearly on reading the following description given by way of illustrative and non-limiting example, and the appended drawings among which:

[0040] [Fig. 1] is a perspective view of one embodiment of a motor-fan unit.

[0041] [Fig. 2] is an exploded view of the motor-fan assembly of Figure 1.

[0042] [Fig. 3a] is a first sectional view of an engine support and a motor of the motor-fan unit of Figure 1.

[0043] [Fig. 3b] is a first sectional view of an engine support and a motor of the motor-fan unit of Figure 1.

[0044] [Fig. 4] is a perspective view of an upper part of a bearing holder of the motor-fan unit of Figures 1 and 2 having a first housing intended to receive a first bearing.

[0045] [Fig. 5] is a perspective view of a lower part of the bearing holder of the motor-fan unit of figures 1 and 2 showing a second housing receiving a second bearing.

[0046] In these figures, identical elements have the same reference numbers.

[0047] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments, without departing from the scope of the invention, as defined by the claims.

[0048] In the description, certain elements may be indexed, for example first element or second element. In this case, it is a simple indexing to differentiate and name close but not identical elements. This indexing does not imply a priority of one element over another and such names can easily be interchanged without departing from the scope of the present invention. This indexing also does not imply an order in time. Detailed description

[0049] Figures 1 and 2 illustrate a motor-fan unit 1, in particular for a vehicle such as a motor vehicle. It may in particular be a motor-fan unit 1 for a heating, ventilation and / or air conditioning installation for a vehicle, in particular a motor vehicle.

[0050] The motor-fan unit 1 (or ventilation device) comprises in particular a fan wheel 3, a motor 5 for driving the fan wheel 3, and a support 7 for the motor 5, hereinafter called the motor support 7.

[0051] The fan wheel 3, in particular of the blower type, rotates around an axis of rotation A. The motor 5 is intended to drive the fan wheel 3 in rotation around its axis A. In the present document, the terms “axial”, “coaxial”, “axially”, “radial” or “radially” are defined in relation to this axis A.

[0052] In particular, the motor 5 is an electric motor. It may in particular be a brushless motor 5 (also known as “brushless”). The motor 5 comprises a rotor 5A and a stator part 5B, the rotor 5A being movable relative to the stator part and capable of driving the fan wheel 3. The rotor 5A is for example an external rotor. The rotor 5A may have a cup shape fixed to a rotor shaft 51. The fan wheel 3 may be fixed directly to the rotor shaft 51. The rotor 5A may comprise magnets for example fixed on an internal face of the cup. The stator part 5B may be internal, that is to say arranged inside the rotor 5A. The stator part 5B comprises a stator and for example at least one stator winding, in particular three stator windings. The 5A rotor magnets can be arranged radially outward relative to the stator windings.The term is understood in relation to the axis of rotation A.

[0053] At least one bearing 9A, 9B is intended to be mounted around the rotor shaft 51. In particular, a first bearing 9A and a second bearing 9B are provided. The or each bearing 9A, 9B comprises an inner ring 91 and an outer ring 93. The rotor shaft 51 can be mounted free, sliding, inside the inner rings 91 of the bearings 9A, 9B.

[0054] The engine support 7 is intended to allow the motor-fan unit 1 to be fixed in the vehicle, in particular an automobile.

[0055] The engine support 7 may include a base 71 allowing the engine to be fixed

[0056] The base 71 may be a unitary base 71, that is to say that there is no range of movement of one element of the base relative to another element. The engine support 7 thus forms a solid block. In other words, the engine support 7 does not comprise two parts or rings that are movable relative to each other.

[0057] The base 71 may be intended to be fixed to the motor 5. The base 71 comprises an opening 72 crossed at least in part by the rotor shaft 51.

[0058] The base 71 may also be intended to be fixed, directly or indirectly, to a structural element of the vehicle, for example a vehicle heating, ventilation and / or air conditioning installation. In the example illustrated, the engine support 7 comprises a fixing interface 73 to which the base 71 is fixed. This fixing interface 73 may advantageously also have an air deflector function allowing, during operation of the motor-fan unit 1, to deflect at least a portion of the air set in motion by the fan wheel 3 towards the control module 7 and / or towards the engine 5. The fixing interface 73 may be intended to be fixed to the vehicle.

[0059] The base 71 may have at least a partial shape of revolution around an axis coinciding, for example, with the axis A of rotation of the fan wheel 3 in the assembled state of the motor-fan unit 1. The base 71 may be centered around this axis A. The axis A hereinafter designates both the axis of the base 71 and the axis of rotation of the fan wheel 3. The base 71 may extend mainly along a plane normal to the axis A. For example, the base 71 has an annular shape, or a ring shape or a disc shape.

[0060] The engine support 7 advantageously carries a control module 11 of the engine 5. In particular, the base 71 can carry the control module 11. The control module 11 can comprise an electronic card (not visible in the figures) and at least one connector electrically connected to the electronic card for the electrical supply of the electronic card and, consequently, of the engine, when it is connected to an electrical harness in particular of the vehicle. In particular, when the electronic card is powered, the stator windings can create a magnetic field causing the rotation of the rotor and consequently of the fan wheel 3. A cover 12 can be fixed on the engine support 7, in particular the base 71, so as to cover the control module 11.

[0061] The engine support 7 further comprises a support part such as a bearing holder 13.

[0062] The bearing holder 13 can be fixed to the base 71 and / or to the air deflector 73.

[0063] The bearing holder 13 may have an upper part 13A and a lower part 13B opposite each other along a central axis of the bearing holder 13 intended to coincide with the axis of rotation A in the mounted state of the engine support with the engine. The terms lower and upper are defined with reference to the orientation of FIG. 1.

[0064] The upper part 13A of the bearing holder 13 is oriented towards the fan wheel 3 when the motor-fan unit 1 is assembled.

[0065] The lower part 13B can be oriented towards a structure of the engine support 7, such as the base 71, when the motor-fan unit 1 is assembled.

[0066] The bearing holder 13 is made at least partly of plastic material. According to a particular embodiment, the plastic material may be reinforced with glass fibers. According to one example, the plastic material may be a thermoplastic, in particular of the polyester type, such as polybutylene terephthalate, with for example 30% glass fiber reinforcement (known under the name PBT GF30).

[0067] The bearing holder 13 defines at least one housing 15, 17 (figures 3a to 5). The housing 15, 17 can receive a bearing 9A, 9B mounted around the rotor shaft 51. The outer ring 93 of the bearing 9A, 9B is mounted tightly in the corresponding housing 15, 17.

[0068] At least one sealing element 18 (figures 3a, 3b) can be arranged, in particular compressed, between on the one hand the base 71 and on the other hand the bearing 9B and the corresponding housing 17 defined by the bearing holder 13 opposite the base 71.

[0069] This sealing element 18 can be produced by overmolding. More precisely, it can be secured to the base 71 by overmolding. It is chosen for example from an elastomer material. The elastomer material is for example polystyrene-b-poly(ethylene-butylene)-b-polystyrene or SEBS.

[0070] The sealing element 18 has, for example, a primary part 181 and an extension 182 extending, for example axially, from the primary part 181. The extension 182 extends in particular in the direction of the base 71.

[0071] The primary part 181 can be arranged between, on the one hand, the base 71 and, on the other hand, the bearing 9B and the corresponding housing 17 defined by the bearing holder 13 opposite the base 71.

[0072] The extension 182 of the sealing element 18 can match an internal contour of the base 71 delimiting the opening 72 crossed at least in part by the rotor shaft 51.

[0073] Furthermore, the base 71 may comprise one or more branches of elastomeric material, connected to the primary part 181 and / or the extension 182. These branches may be provided around passages or openings in the base 71, for example for terminals and / or around fixing points, or even around the control module. These branches may provide a sealing function and / or a decoupling function to limit the transmission of vibrations generated by the engine 5 and / or the fan wheel 3 in the vehicle and / or external stresses towards the engine 5 and / or the fan wheel 3.

[0074] The sealing element 18 can be traversed at least in part by the rotor shaft 51. For this purpose, it comprises an opening 183. This opening 183 of the sealing element 18 can be aligned with the opening 72 of the base 71.

[0075] The primary part 181 of the sealing element has a shape matching the shape of the housing 17 receiving the bearing 9B opposite the base 71.

[0076] The primary part 181 has, for example, the shape of an openwork plate, particularly in its center. The extension 182 may have the shape of a collar or a ring.

[0077] According to one embodiment, the bearing holder 13 defines at least a first housing 15 and a second housing 17 (FIGS. 3a to 5). The first housing 15 is for example arranged on the upper part 13A of the bearing holder 13. The second housing 17 is for example arranged on the lower part 13B of the bearing holder 13. This second housing 17 is arranged opposite the base 71.

[0078] The housings 15, 17 are configured to receive the corresponding first and second bearings 9A, 9B. More specifically, the first bearing 9A can be mounted in the first housing 15. The second bearing 9B can be mounted in the second housing 17.

[0079] The sealing element 18 can be arranged between the base 71 on the one hand and the second bearing 9B and the second housing 17 on the other hand.

[0080] Furthermore, during assembly, the outer rings 93 of the bearings 9A, 9B are force-fitted inside the housings 15, 17. The bearings 9A, 9B can be inserted with the same force into the housings 15, 17 on both sides of the bearing holder 13, without distinction of the flexibility or rigidity of the bearing holder 13 at the level of the housings 15, 17.

[0081] Due to this forceful insertion of the outer rings 93 of the bearings 9A, 9B into the bearing holder 13 and the rotor shaft 51 slidably mounted inside the bearings 9A, 9B, in operation, the bearings 9A, 9B do not move while the rotor shaft 51 moves through the inner rings 91 of the bearings 9A, 9B.

[0082] The housings 15, 17 defined by the bearing holder 13 are of a shape complementary to that of the bearings 9A, 9B. The housings 15, 17 have, for example, a general annular or crown shape.

[0083] At least one or both of the housings 15, 17 may be shaped so as to allow the stresses generated by the insertion of a bearing 9A, 9B into the corresponding housing 15, 17 to be released.

[0084] For this purpose, at least one housing 15, 17 may have at least one stress relief zone 25 (FIGS. 4A, 4B). This may in particular be an area of ​​the housing 15, 17 which is more flexible than the rest of the housing 15, 17. This allows the bearing holder 13 to open, or deform, slightly at the level of the housing 15, 17 to allow the insertion of the corresponding bearing 9A, 9B and limit the forces required.

[0085] Such a zone 25 may have a deformation. The deformation is for example chosen from a semi-circular shape, a wave shape, an accordion shape, a rectangular shape, a triangular shape, a curved shape, a convex shape, a concave shape.

[0086] For example, the stress relief zone 25 is a domed or convex shape with convexity oriented towards the outside of the housing 15, 17. The stress relief zone 25 is in particular domed or convex in the direction of a force applied from the inside to the outside of the housing 15, 17 during insertion of the corresponding bearing 9A, 9B.

[0087] Alternatively or additionally, a stress relief zone 25 may have a reduced thickness compared to the rest of the housing 15, 17.

[0088] According to yet another variation, a more flexible material than the material used for the remainder of the housing 15, 17 may be used to provide the flexibility necessary for stress relief.

[0089] The two housings 15, 17 may each have at least one respective stress relief zone 25.

[0090] When the two housings 15, 17 have one or more stress relief zones 25, they may be identical or on the contrary different between the two housings 15, 17.

[0091] According to an exemplary embodiment, the stress relief zones 25 can extend axially, that is to say along the central axis of the bearing holder 13 coinciding with the axis of rotation A.

[0092] Also, when the two housings 15, 17 have one or more stress relief zones 25, they can be aligned along the central axis of the bearing holder 13 coinciding with the axis of rotation A.

[0093] Alternatively, the stress relief zones 25 of the two housings 15, 17 may not be axially aligned.

[0094] One of the housings 15, 17 or each housing 15, 17 may have several stress relief zones 25 which may be regularly distributed.

[0095] According to a particular embodiment, the housing 15, 17 may have at least three stress relief zones 25. They are preferably regularly distributed at 120°. In the example illustrated, each of the two housings 15, 17 has three stress relief zones 25. Of course, this is not limiting.

[0096] The at least one stress relief zone 25 is spaced from the bearing 9A, 9B received in the housing 15, 17.

[0097] The sealing element 18 which is arranged between on the one hand the base 71 and on the other hand a bearing 9B and the corresponding housing 17, such as the second bearing 9B and the second housing 17, is located opposite the space between the at least one stress relief zone 25 and the bearing 9B. This makes it possible to prevent any liquid from passing through this space between the bearing 9B and the stress relief zone(s) 25.

[0098] The primary part 181 of the sealing element 18 has a shape conjugate to the shape of F at least one stress relief zone 25 of the housing 17 receiving the bearing 9B opposite the base 71. This is for example at least one radial protuberance 184 which comes opposite a stress relief zone 25. According to a particular example of F at least one stress relief zone 25 with a semi-circular shape, F at least one radial protuberance 184 is for example in the form of an ear (figure 3b) of a shape complementary to the semi-circular shape of the stress relief zone 25.

[0099] Furthermore, referring again to Figures 3a to 5, the internal wall of one or more housings 15, 17 may be provided with one or more radial support reliefs 151, 171.

[0100] In particular, the at least one housing 17 which is arranged opposite the base 71 has on its internal wall an alternation of at least one radial support relief 171 and at least one hollow 172 between the internal wall of the housing 17 and the bearing 9B. In this case, the sealing element 18 is arranged opposite the at least one hollow 172.

[0101] The radial support relief(s) 151, 171 are shaped so as to establish contact with the first 9A or the second 9B corresponding bearing. The contact may be linear or surface.

[0102] The first housing 15 and the second housing 17 may or may not have the same number of radial support reliefs 151, 171.

[0103] At least one of the housings 15, 17 may have at least three radial support reliefs 151, 171. These three radial support reliefs 151, 171 are preferably regularly distributed at 120° from one another. Of course, this is not limiting; it may, for example, be envisaged to increase the number of radial support reliefs 151, 171 to improve the coaxial position of the bearings 9A, 9B in the housings 15, 17 and make the assembly even more secure.

[0104] Each radial support relief 151, 171 can define at least one support or contact surface against the corresponding first 9A or second 9B bearing. The radial support reliefs 151 of the first housing 15 define, for example, support surfaces against the first bearing 9A. The radial support reliefs 171 of the second housing 17 define, for example, support surfaces against the second bearing 9B.

[0105] Furthermore, the radial support reliefs 151 of the first housing 15 may be different from the radial support reliefs 171 of the second housing 17.

[0106] The radial support reliefs 151 of the first housing 15 may be of different shapes compared to the radial support reliefs 171 of the second housing 17. In particular, the radial support reliefs 151 of the first housing 15 may define support surfaces which are larger than the support surfaces defined by the radial support reliefs 171 of the second housing 17.

[0107] According to one embodiment of the first housing 15, the radial support reliefs 151 are shaped to establish surface contact with the first bearing 9A.

[0108] To do this, the radial support reliefs 151 are, for example, included in a hypothetical cylindrical shape surrounding the first bearing 9A.

[0109] The radial support reliefs 151 may, for example, have a contact surface with a rectangular or triangular outline. They may also be prismatic in shape.

[0110] According to one embodiment of the second housing 17, the radial support reliefs 171 are shaped to establish linear contact with the second bearing 9B. The radial support reliefs 171 may for example have a rounded contact surface to establish linear contact with the second bearing 9B. In particular, the radial support reliefs 171 may be of circular or semi-circular shape making it possible to establish linear contact with the bearing 9B. [OR I] According to a variant not shown, the radial support reliefs 171 could be shaped to establish surface contact with the second bearing 9B. When the radial support reliefs 151, 171 of the two housings 15, 17 are shaped to establish surface contacts with the corresponding bearing 9A, 9B, the surface contact established between the radial support reliefs 171 of the second housing 17 and the second bearing 9B may be less significant than the surface contact established between the radial support reliefs 151 of the first housing 15 and the first bearing 9A.

[0112] Furthermore, the radial support reliefs 151 of the first housing 15 and / or the radial support reliefs 171 of the second housing 17 may be produced by ribs.

[0113] The radial support reliefs 151 such as ribs of the first housing 15 may optionally be axially aligned with the radial support reliefs 171 such as ribs of the second housing 17. Alternatively, the radial support reliefs 151, 171 of the first housing 15 and of the second housing 17 may be arranged independently, so that the radial support reliefs 171 of the second housing 17 do not are not necessarily axially aligned with the radial support reliefs 151 of the first housing 15.

[0114] In addition, the bearing carrier 13 may comprise a base 131 and a tower or chimney 133.

[0115] The tower 133 may be tubular in shape around the central axis of the bearing part 13 coinciding with the axis of rotation A. This tower 133 extends for example axially from the base 131. The tower 133 may end with the first housing 15. In other words, the first housing 15 is located at one end of the tower 133.

[0116] The tower 133 has an internal surface delimiting a cavity. This cavity allows the first bearing 9A to be received. At this end, the internal surface of the tower 133 therefore faces the first bearing 9A when the latter is received in the first housing 15.

[0117] The tower 133 may comprise one or more external stiffening fins 19. The fins 19 are said to be external because they are provided on an external surface of the tower 133 which is opposite the internal surface of the tower 133.

[0118] Such fins 19 may extend axially from the base 131 along the tower 133. The fins 19 may terminate at a non-zero distance d from the end of the tower 133 which is opposite the base 131.

[0119] The base 131, for its part, comprises the second housing 17 in particular with its radial support reliefs 171. The first housing 15 is arranged at the end of the tower 133 opposite this second housing 17 along the axis A.

[0120] The sealing element 18 is arranged between this base 131 of the bearing holder 13 and the base 71, for example annular, of the motor support 7. The sealing element 18 is then trapped and compressed between the base 131 of the bearing holder 13 and the bearing 9B on one side and the base 71 of the motor support on the other side.

[0121] With reference to figures 3b and 5, the bearing holder 13, and in particular its base 131 can be fixed to a structure of the engine support, such as the base 71 previously described, by means of at least one mechanical fixing member 20. For this purpose, the base 131 can comprise a predefined number of fixing points 21, such as bosses, screw points allowing the passage for example of the mechanical fixing member 20.

[0122] The sealing element 18 is arranged around the mechanical fixing member(s) 20 and in particular the fixing points 21. The sealing element 18 has for this make one or more portions 185, for example in the form of washers or rings, arranged around the mechanical fixing members 20 and / or the fixing points 21.

[0123] According to one embodiment, the base 131 may be more rigid than the end of the tower 133 which is free, not fixed to a structure, opposite the base 131. The fixing points 21 such as bosses, and / or reinforcing elements make it possible to further stiffen the base 131.

[0124] The free end of the tower 133 is in this case more flexible than the base 131, in particular due to the height of the tower 133. In addition, at its free end, the tower 133 may have a smaller thickness than at the base 131.

[0125] One or more stress relief zones 25 may be provided at least on the side of the base 131 which is more rigid than the end of the tower 133. Thus at least the second housing 17 may have such stress relief zones 25. The first housing 15 may also have such stress relief zones 25. In the example illustrated, both housings 15, 17 have stress relief zones 25.

[0126] According to an exemplary embodiment, the stress relief zones 25 may extend axially from the base 131 to the opposite end of the tower 133.

[0127] Furthermore, due to the greater rigidity on the side of the base 131, the radial support reliefs 171 of the second housing 17, when they are provided, can be shaped to establish a linear or point (or even surface) contact. On the other hand, on the side of the more flexible end of the tower 133, the radial support reliefs 151, when they are provided, are preferably shaped to establish a greater surface contact in order to prevent in particular the first bearing 9A from coming out of the first housing 15 during operation in the event of possible vibrations for example.

[0128] This makes it possible to obtain a larger friction zone between the first bearing 9A and the first housing 15 (compared to the second housing 17) and makes it possible to limit, for example, outward deformation of the first housing 15 during insertion of the first bearing 9A. Thus, the assembly of the bearings 9A, 9B in the two housings 15, 17 can be homogenized, for example, with the same force on the sides (base 131 and end of the tower 133) so as not to require modification of an assembly tool depending on the side, for example.

[0129] Furthermore, when the first 9A, respectively second 9B, bearing is inserted into the first 15, respectively second 17, housing, the contact surface is therefore reduced compared to the solutions of the prior art whose housings are defined by smooth cylinders. According to the embodiment described, the radial support reliefs 151, 171 define one or more small contact sections with the corresponding bearing 9A, 9B. The stresses generated by the insertion of a bearing 9A, 9B into the corresponding housing 15, 17, are concentrated at the level of the radial support reliefs 151, 171 and the stress release zones 25 make it possible to release these stresses.

[0130] Thus, the outer rings 93 of the bearings 9A, 9B can be force-fitted into the housings 15, 17 on both sides of the bearing holder 13 made of plastic material. The force-fitting of the bearings 9A, 9B is advantageously secured thanks to the presence of the respective radial support reliefs 151, 171 on the internal surfaces of the housings 15, 17. And, the stresses generated during the force-fitting of one or more bearings 9A, 9B are released thanks to the flexibility of stress-relieving zones 25 of the housing(s) 15, 17.

[0131] The sealing element 18 compressed between the base 71 and the bearing holder 13 is shaped so as to cover the hollows 172 between the support reliefs 171 of the housing 17 opposite the base 71, as well as any spaces between the stress relief zones 25 and the bearing 9B.

[0132] In the assembled state of the motor-fan unit 1, the sealing element compressed between the base 71 of the motor support 7, and the bearing 9B and the housing 17 of the bearing holder 13 ensures sealing against a liquid and / or air which would come for example from below the fan wheel 3 when the latter is started, according to the orientation of the elements in figure 1.

Claims

Claims

1. Motor-fan unit (1) in particular for a motor vehicle, the motor-fan unit (1) comprising: a fan wheel (3), a motor (5) for driving the fan wheel (3), a motor support (7) comprising at least one base (71) and a bearing holder (13) made at least partly of plastic material, • the base (71) comprising an opening (72) crossed at least in part by a rotor shaft (51) of the drive motor (5) and • the bearing holder (13) defining at least one housing (17) receiving at least one bearing (9B) mounted around the rotor shaft (51), • characterized in that the motor-fan unit (1) comprises at least one sealing element (18) arranged between on the one hand the base (71) and on the other hand the bearing (9B) and the housing (17) defined by the bearing holder (13) opposite the base (71), the sealing element being crossed at least in part by the rotor shaft (51).

2. Motor-fan unit (1) according to the preceding claim, in which F at least one housing (17) comprises an internal wall having an alternation of at least one radial support relief (171) shaped to establish contact with the bearing (9B) and at least one hollow (172) between the internal wall of the housing (17) and the bearing (9B), and in which the sealing element (18) is arranged opposite F at least one hollow (172).

3. Motor-fan unit (1) according to one of the preceding claims, in which F at least one housing (17) has at least one stress relief zone (25) spaced from the bearing (9B) received in the housing (17), and in which the sealing element is arranged opposite the space between F at least one stress relief zone (25) and the bearing (9B).

4. Motor-fan unit (1) according to one of the preceding claims, in which the sealing element (18) has a primary part (181) and an extension (182) extending from the primary part (181), such that: the primary part (181) is arranged between on the one hand the base (71) and on the other hand the bearing (9B) and the housing (17) defined by the bearing holder (13), and the extension (182) follows an internal contour of the base (71) delimiting the opening (72) crossed at least in part by the rotor shaft (51).

5. Motor-fan unit (1) according to claims 3 and 4 taken together, in which the primary part of the sealing element (18) has a shape combined with the shape of the housing (17) receiving the bearing (9B) opposite the base (71), and of the at least one stress relief zone (25) of said housing (17).

6. Motor-fan unit (1) according to one of the preceding claims, in which: the bearing holder (13) defines at least a first housing (15) and a second housing (17), the second housing (17) being arranged opposite the base (71), at least a first bearing (9A) and a second bearing (9B) corresponding to each other are mounted respectively in the first housing (15) and in the second housing (17), around the rotor shaft (51), and the sealing element (18) is arranged between on the one hand the base (71) and on the other hand the second bearing (9B) and the second housing (17) defined by the bearing holder (13).

7. Motor-fan unit (1) according to the preceding claim, in which the bearing holder (13) comprises: a base (131) defining the second housing (17), the sealing element (18) being arranged between the base (71) and the base (131) of the bearing holder (13), and a tower (133) of tubular shape around a central axis (A) of the bearing holder (13), extending axially from the base (131) and ending with the first housing (15) opposite the second housing (17) along the central axis (A).

8. Motor-fan unit (1) according to one of the preceding claims, in which the at least one bearing (9A, 9B) comprises an inner ring (91) and a respective outer ring (93), the outer ring (93) being tightly mounted in the housing (15, 17).

9. Motor-fan unit (1) according to one of the preceding claims, comprising at least one mechanical fixing member (20) between the base (71) and the bearing holder (13), and in which the sealing element (18) is arranged around the mechanical fixing member (20).

10. Motor-fan unit (1) according to one of the preceding claims, in which the sealing element (18) is secured to the base (71) by overmolding.

11. Motor-fan unit (1) according to one of the preceding claims, in which the sealing element (18) is made of an elastomeric material, in particular polystyrene-b-poly(ethylene-butylene)-b-polystyrene.

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