Patent ID: 12187095

DESCRIPTION OF EMBODIMENTS

In the remainder of the description, elements that are identical or perform identical functions have been designated with the same reference sign. In the present description, for the sake of conciseness, these elements are not described in detail in each embodiment. Rather, only the differences between the variant embodiments are described in detail.

FIG.1illustrates a fan device10for a vehicle ventilation installation.

The fan device10essentially comprises, as shown, a fan impeller12, an electric motor14, and a support16for the electric motor14. The fan impeller12rotates about an axis of rotation A. The electric motor14is intended to drive in rotation, about its axis A, the fan impeller12. The support16for the motor14is intended to allow the fixing of the fan device10in a motor vehicle, by limiting the transmission of the vibrations generated by the electric motor14and/or the fan impeller12in the motor vehicle and/or external stresses toward the electric motor14and/or the fan impeller12. The support16for the motor14may in particular have two coaxial rings, of axis A of rotation of the fan impeller12, interconnected by elastomer material. In particular, the elastomer material can form a decoupling ring between the inner ring and the outer ring. The inner ring may be intended to be fixed to the motor14. The outer ring may be intended to be fixed to a structural element, in particular of a vehicle ventilation installation. The elastomer material is for example polystyrene-b-poly(ethylene-butylene)-b-polystyrene or SEBS.

The electric motor14here forms a mechanical assembly comprising a rotating element18, in this case the rotor18of the motor14, a support20for the rotor18, and a cover22, fixed on the support20for the rotor18. Here, the cover22is fixed on the support20for the rotor18by means of screws24. Of course, other fixing means can be implemented to fix the cover22on the support20for the rotor18.

In this instance, the rotor18is an external rotor. Thus, the stator26associated with the rotor18is arranged radially inside the rotor18. More specifically, the magnets27of the rotor18are radially on the outside with respect to the winding of the stator26.

The rotor18has the shape of a perforated cup28, fixed to a shaft30. Here, the fan impeller12is fixed directly on the shaft30. In this instance, the magnets27of the rotor18are fixed on the internal face of the cup28, on a cylindrical strip32formed by the cup28.

The support20is for example made of an aluminum alloy or a plastics material filled with metal particles.

Here, the support20for the rotor18has a base34. In this instance, the base34extends wholly in a plane normal to the axis A of rotation of the motor14. A substantially cylindrical relief36extends from the base34. Here, the relief36extends substantially in the direction of the axis A of rotation of the motor14. The relief36is hollow. The relief36may in particular form one or two housings38each accommodating a bearing ring, in particular a ball bearing, intended to guide the rotation of the shaft30with respect to the support20. In particular, a first housing is formed at the free end of the relief36and a second housing is formed in the relief36, substantially at the base34. A ball bearing is accommodated in each of these housings.

As can be seen more particularly inFIG.5, the base34forms on its surface opposite to the cylindrical relief36a recess40accommodating a printed circuit board42(or electronic board) for controlling the motor14. The recess40may be surrounded by a projecting rim41. Various mechatronic components44,46are fixed on the printed circuit board42. In particular, mechanical devices44make it possible to connect lugs integral with the windings of the stator26to the printed circuit board42. The power supply of these windings via these lugs can then allow the control of the electric motor14. The bulkiest components46, in particular the capacitors, may also be fixed on the printed circuit board42, preferably near the edges of the printed circuit board42.

A connector48is also connected to the printed circuit board42. The connector48allows the supply of electric power to the printed circuit board42and, consequently, to the motor14.

Lastly, the cover22is fixed on the base34of the support20. In this instance, the cover22defines, with the recess40in the base34, a housing for accommodating the printed circuit board42. Here, the cover22comprises a substantially planar edge50extending in a plane normal to the axis A of rotation of the motor14. The edge50has holes51allowing the fixing of the cover22on the base34of the support20, by means of screws24. The cover22also comprises a bottom52, remote from the edge50, in the direction of the axis A of rotation of the motor14. The bottom52is in this instance substantially planar. The bottom52extends substantially in a plane normal to the axis A of rotation of the motor14. The bottom52of the cover22is in this instance substantially parallel to the base34of the support20. Here, the bottom52of the cover22is also substantially parallel to the printed circuit board42.

The cover22is for example made of aluminum alloy or plastic filled with conductive particles, in particular plastic filled with metal particles.

It should be noted here that the cover22shown comprises peripheral bosses54,56. These bosses54,56make it possible to accommodate the bulkiest electronic devices46, in particular those which are tallest in the direction of the axis A of rotation of the motor14.

In the example illustrated inFIGS.6and7, in particular, the cover22also has a planar surface53, closer to the edge50than the bottom52, in the direction of the axis A of rotation of the motor14.

Lastly, as can be seen in the figures, the cover22and the printed circuit board42may each have a through-opening60,62facing the shaft30of the rotor18. These openings60,62can allow the passage of a counter-support for the shaft30, allowing the impeller12to be fitted on the shaft30. The opening60in the cover can then be closed, in particular by means of a sticker. This makes it possible to protect the printed circuit board42against the humidity of the ambient air.

In the following text, a more detailed description will be given of examples of a rotor cup28of a motor with an external rotor, which can be implemented in the motor14of the ventilation device10described above.

A first example of a cup28is illustrated inFIGS.8and9.

As can be seen in these figures, the cup28exhibits symmetry of revolution, about an axis A of symmetry corresponding to the axis of rotation of the cup28and the motor14.

The cup28essentially has a first, radially inner cylindrical portion68and a second, radially outer cylindrical portion32. The second cylindrical portion32corresponds to the cylindrical strip32described above, on which the magnets27of the rotor18are fixed. The magnets27are fixed on the radially internal face of the second cylindrical portion32.

The first cylindrical portion68extends over a height h68, measured in the direction of the axis A of symmetry of the cup28. The height h68of the first portion68may be such that the ratio between the height h68of the first cylindrical portion68and the radius R32of the second cylindrical portion32is between 0.8 and 0.98. Such a range is notably advantageous if the shaft30is force-fitted in the first portion68. As an alternative, however, the shaft30may be fixed to the cup28by welding. In this case, the height h68of the first portion can be considerably reduced, in particular close to 0. The first cylindrical portion68accommodates the shaft30of the motor14. The shaft30is for example force-fitted in this first cylindrical portion68. As an alternative or in addition, the shaft30may be welded to the first cylindrical portion68.

Thus, since the shaft30is supported by two ball bearings, along the shaft30in the following order there are:the zone in which the shaft30is fitted in the first cylindrical portion68—and more generally, the first cylindrical portion68;a first ball bearing,the stator, separated from the shaft by the cylindrical relief36of the support20for the rotor18, anda second ball bearing.

The second cylindrical portion32extends over a height h32, measured in the direction of the axis A of symmetry of the cup28, such that the ratio between the height h32of the second cylindrical portion32and the radius R32of the second cylindrical portion32is between 0.30 and 0.60.

Between the first cylindrical portion68and the second cylindrical portion32, the cup28has a third portion70such that, as seen in section, the third portion70extends between a first, radially inner point P1and a second, radially outer point P2, the straight line connecting the first and second points P1, P2forming an angle α of between 65° and 80° with the axis A of symmetry of the cup28. In this way, the third portion70of the cup28has a frustoconical overall shape, thereby helping to stiffen the cup28. However, the angle at the center of this third portion70is limited so as to limit the axial bulk of the cup28. In this instance, the third portion70is frustoconical, the third portion70extending, in section, substantially along the straight line connecting the first and second points P1, P2.

In the example illustrated, the ratio between the distance RP1between the first point P1and the axis A of symmetry of the cup28, on the one hand, and the radius R32of the second cylindrical portion32, on the other hand, is between 0.04 and 0.32. Moreover, the ratio between the distance RP2between the second point P2and the axis A of symmetry of the cup28, on the one hand, and the radius R32of the second cylindrical portion32, on the other hand, is between 0.65 and 1.0. In this way, the third portion70, of frustoconical overall shape, extends over most of the surface of the cup28, ensuring the stiffness of this cup28. It should be noted here that the radius R32of the second portion32is the outer radius of the rotor cup28.

In the example illustrated inFIGS.8and9, the third portion70has openings72separated by arms74. Here, the cup28comprises seven arms74, separating seven openings72. More generally, to limit the risks of natural modes of the cup28arising at relatively low frequencies, the cup28advantageously comprises a prime number of arms74. This number of arms is preferably greater than or equal to seven. The openings72make it possible to further reduce the weight of the cup28. The openings72likewise make it possible to facilitate the cooling of the windings of the stator accommodated inside the cup28.

To maintain a satisfactory stiffness of the cup28, the arms74may have a substantially trapezoidal shape. The arms74thus define openings72which are also trapezoidal. In this instance, each arm74has a minimum width I74, measured in an orthoradial direction with respect to the axis A of symmetry of the cup28, such that the ratio of this minimum width I74to the radius R32of the second cylindrical portion32is between 0.08 and 0.30. Each arm74likewise has a maximum width L74, measured in an orthoradial direction with respect to the axis A of symmetry of the cup28, such that the ratio of this maximum width L74to the radius R32of the second cylindrical portion32is between 0.08 and 0.45. Advantageously, the maximum width L74of an arm74is measured at the radially outer end of the arm74in question, whereas the minimum width L74is measured at the radially inner end of the arm74in question.

In the example ofFIGS.8and9, the cup28further comprises a fourth, annular portion76. In this instance, the fourth portion76forms a recess with respect to the radially inner end of the third portion70and to the first cylindrical portion68. The fourth portion76is located radially between the first portion68and the third portion70. Here, the fourth portion76is normal to the axis A of symmetry of the cup28. The ratio between the inner radius R76iof the fourth portion76and the radius R32of the second portion32is for example between 0.05 and 0.24. As an alternative or in addition, the ratio between the outer radius R76eof the fourth portion76and the radius R32of the second portion32is for example between 0.15 and 0.30. Thus, advantageously, this fourth, annular portion76has a reduced area. This fourth portion76, forming a recess, makes it possible to further stiffen the cup28. The fourth portion76is for example connected to the first cylindrical portion68by a bend. In this instance, the fourth portion76is adjacent to the third, frustoconical portion70.

The cup28ofFIGS.8and9further comprises a fifth, flared portion78between the second portion32and the third portion70. More specifically, in section, the fifth portion78forms a bend. Here, the fifth portion78is adjacent to the third, frustoconical portion70, on one side, and to the second cylindrical portion32, on the other side. This fifth portion78, forming a bend, also makes it possible to stiffen the cup28.

Advantageously, the cup28is formed by the first, second, third, fourth and fifth portions68,32,70,76,78and, possibly, the bend connecting the first portion68to the fourth portion76.

In this instance, the cup28is made from metal. The cup28preferably has a thickness less than or equal to 3 mm, further preferably less than or equal to 2 mm, more preferably a thickness equal to 1.6 mm. This limits the weight of the cup28.

Between the first portion68and the fourth portion76, the cup forms a bend here. The bend may have a thickness e2, which is greater than the thickness e1of the first portion68. The ratio between the thickness e2and the thickness e1may in particular be greater than or equal to 1.3 and/or less than or equal to 1.6. A thicker bend makes it possible to strengthen the cup28. For example, the thickness e1is equal to 1.8 mm. The maximum thickness e2of the bend may be equal to 2.8 mm.

FIG.10illustrates a variant of the cup28ofFIGS.8and9. This variant differs from the cup28ofFIGS.8and9first of all by the “Y” shape of the arms74, comprising a stem741dividing into two branches742,743, which are identical in this instance, in the vicinity of its radially internal end. In this instance, the stem of each arm74has a width I741, measured in an orthoradial direction with respect to the axis A of symmetry of the cup28, such that the ratio of this width I741to the radius R32of the second cylindrical portion32is between 0.08 and 0.22. Each branch742,743likewise has a width I742, measured in an orthoradial direction with respect to the axis A of symmetry of the cup28, such that the ratio of this width I742to the radius R32of the second cylindrical portion32is between 0.04 and 0.12.

Due to the shape of the arms74in this variant, the openings72here are in the form of an ogive, with a rounded radially inner end. The width L72of the openings72, at their radially outer end, measured in an orthoradial direction, is such that the ratio between this width L72and the radius R32of the second cylindrical portion32is between 0.4 and 0.9.

In addition, the two branches742,743of each arm74define a hole80. Each hole80has a considerably reduced area in comparison with the openings72. In this instance, the holes80are also in the form of an ogive, oriented in an opposite direction to the openings72. In other words, here the rounded end of the holes80is oriented radially outward.

FIG.11illustrates a second embodiment of the cup28.

This second example of a cup comprises, preferably consists of, a first cylindrical portion68, a second cylindrical portion32, a third portion70, extending between the first portion68and the second portion32, and, in this instance, a bend between the first portion68and the third portion70. In this instance, the third portion70is adjacent to the second portion32.

Here, too, the third portion70is such that, as seen in cross section, the third portion70extends between a first, radially inner point P1and a second, radially outer point P2, the straight line connecting the first and second points P1, P2forming an angle α of between 65° and 80° with the axis A of symmetry of the cup28. In this way, the third portion70of the cup28has a frustoconical overall shape, thereby helping to stiffen the cup28. However, the angle at the center of this third portion70is limited so as to limit the axial bulk of the cup28.

However, as can be seen inFIG.11, here the third portion70is flared in the direction of the second cylindrical portion32. More particularly, the third portion70has a concave appearance. In other words, the third portion70is, as seen in section, located below the straight line connecting the end points P1, P2of the third portion70. In other words still, the segment connecting the end points P1, P2of the third portion70is not included in the cup28.

The third portion70of the second example of a cup28ofFIG.11has arms74in the form of a “Y”, like those described above with reference toFIG.10. As an alternative, however, the second example of a cup28may have trapezoidal arms74, as described with reference toFIG.8. Only the shape, as seen in section, of the arms74differs in the second example of a cup28ofFIG.11.

In this example, the cup28has a bend between the first portion68and the third portion70. The bend may have a thickness e2, which is greater than the thickness e1of the first portion68. The ratio between the thickness e2and the thickness e1may in particular be greater than or equal to 1.3 and/or less than or equal to 1.6. A thicker bend makes it possible to strengthen the cup28. For example, the thickness e1is equal to 1.8 mm. The maximum thickness e2of the bend may be equal to 2.8 mm.

The invention is not limited to the exemplary embodiments described with regard to the figures, and further embodiments will become clearly apparent to a person skilled in the art. In particular, the various examples may be combined, provided they are not contradictory.

In particular, the various examples described above may be combined.