Housing for providing a permanent-magnet motor of an air blower with an air cooling

Abstract

According to an embodiment, a housing is disclosed for providing a permanent-magnet motor for driving an impeller (210) of an air blower (101) to be provided with an air cooling, comprising a cylindrical cavity (211) for housing the permanent-magnet motor, and further comprising two openings (213, 214) at the first and second end of the cavity (211) for guiding an airflow radially toward the motor when housed, a first set of cooling channels between the openings (213, 214) and connected thereto for guiding the airflow tangentially around the motor, and a second set of cooling channels connected to the first set for guiding the airflow radially from the outside of the casing to said first set, wherein the housing further comprises a diversion channel (105) on the outside of the casing for guiding the airflow between the first (213) and second (214) opening, respectively, on the one hand, and the second set on the other hand.

Description

DescriptionTitle of Invention: HOUSING FOR PROVIDINGA PERMANENT-MAGNET MOTOR OF ANAIR BLOWER WITH AN AIR COOLINGTechnical Field

[0001] The present invention relates to the technical field of centrifugal compressors, also called turbo compressors, air blowers or simply blowers. More specifically, the invention relates to a housing for housing a permanent-magnet motor for driving an impeller of an air blower in order to provide this motor with a cooling with a gas.

[0002] The present invention further relates to methods of cooling with a gas, such as air, a permanent-magnet motor for driving an impeller of an air blower using this housing. State of the art

[0003] An air blower, or simply a blower, is a machine in which energy is exchanged between a flow of a fluid and a blade system that performs a rotary movement. In the case of a blower, the blade system is also referred to as an impeller.

[0004] The impeller provides the flow and is driven by a motor, such as, for example a permanent-magnet motor. The permanent-magnet motor then directly drives the impeller.

[0005] During operation, heat will be generated by the engine. For reasons of safety and efficiency, as well as the life span of the machine, this heat must be dissipated by providing a cooling system.

[0006] In US10533560B2, a directly-drive turbo blower is disclosed, comprising a housing, provided with holes, to cool the stator of the engine with air. A disadvantage of this, however, is that it cannot be guaranteed that the rotor of the engine is also cooled efficiently.

[0007] It is therefore an object of the present invention to provide a housing for a blower for housing a permanent-magnet motor wherein the motor can be cooled more efficiently without compromising its proper operation. It is also an object of the present invention to provide methods for cooling the motor using the disclosed housing.Summary of the invention

[0008] According to the present invention, the above-identified object is achieved by, according to a first aspect of the invention, providing a housing according to the first claim, the housing configured to provide an air cooling to a permanent-magnet motor, configured to drive an impeller of an air blower, the housing, comprising a cylindrical cavity, configured to house the permanent-magnet motor, and further comprising a casing, comprising:- a first set and a second set of opposed openings at the first and second end of the cavity, respectively, the set of openings configured to direct an airflow radially from the outside of the casing towards the rotor of the permanentmagnet motor when housed;- a first set of cooling channels between and connected to the set of openings on the rotor and configured to direct the airflow axially around the permanentmagnet motor when housed;- a second set of cooling channels connected to the first set of cooling channels, configured to direct airflow radially from the outside of the casing to said first set; wherein the housing further comprises a diversion channel on the outside of the casing, configured to direct airflow between an opening of the first or second set of openings on one side and the second set of cooling channels on the other side.

[0009] The present invention is described using certain terms or definitions. Here, “direction” is understood to mean along which (imaginary) line it is possible to move, while “sense” is understood to mean to which side of this line, indicated by the direction, it is possible to move. A movement is, for example, the movement of an air flow.

[0010] The housing is a housing, designed to house a permanent-magnet motor which in turn is configured to drive an air blower impeller. This further implies that the housing is a housing, designed for an air blower.

[0011] The housing comprises a cylindrical cavity or cavity in which the permanent- magnet motor can be housed. It should be further understood that this can also comprise a space for bearings to support the rotor of the motor. Furthermore, there is also space provided for the stator. Around this cavity, there is a casing that completely encloses the cavity. This casing comprises two opposite openings at both ends of the cavity. In other words, there are two sets of openings at each end. The term 'opposed' is a geometric term and means that the openings are opposite openings, and preferably 180° opposite each other. These opposite openings per set are configured to guide an air flow radially from the outside to the rotor of the motor. In other words, this means that the air flow can be blown perpendicular to the axial direction of the rotor, and this at both ends. It should be further understood that, as will be explained further, one of the openings per set will be used to direct an airflow from the outside of the casing to the rotor, and the respective opposite opening will be used to direct the airflow from the rotor back to the outside.

[0012] Furthermore, the casing comprises a first set of cooling channels between these two sets of openings, as discussed above, wherein these cooling channels connect to the openings at the rotor. These cooling channels run around the cavity, hence axially andtangentially around the engine when it is housed therein. In addition, there is a second set of cooling channels connecting to those of the first set of cooling channels and configured to guide the airflow radially from the outside of the casing to the cooling channels of the first set.

[0013] Furthermore, in accordance with a novel and innovative feature, the housing comprises a diversion channel on the outside of the casing, configured to guide the airflow between an opening of the first or second set of openings on the one hand and the second set of cooling channels on the other hand. Depending on the direction and sense of the airflows, as will be further explained, the airflow can then be guided from the first or second set of openings to the cooling channels of the second set, or vice versa. The airflow can then flow according to a path along and around the permanentmagnet motor and along an air gap between the rotor and the stator, as described below.

[0014] According to a first possibility, an air flow is blown through a first opening of the first set of openings. This causes the air flow to be blown radially towards the rotor, and the air flows further through the opposite opening of the first set of openings. At the second opening, the air then flows radially away from the motor to the outside of the housing. By providing a diversion channel, the air flow will then be forced to flow further through the cooling channels of the second set of cooling channels, which then connect to the cooling channels of the first set. This creates an air flow around and along the permanent-magnet motor. According to a second possibility, air is initially blown through an opening of the second set of openings, but the air flow follows the same path, such that, with this second possibility, air is also circulated around the motor.

[0015] According to an embodiment, the casing further comprises an airflow obstruction, configured to impede a flow-through of the air flow below a predefined pressure. For example, the predefined pressure is greater than 100 mbar, but it should be noted that this specified value should not be interpreted as limiting, but that other values are also possible. There are two possibilities for the placement of the airflow obstruction.

[0016] According to a first embodiment, the airflow obstruction is placed on the outside of the casing at an opening of the first or second set of openings such that the airflow is forced towards an air gap between the rotor and the stator of the permanent-magnet motor when housed, the air gap extending axially between the first and second set of openings.

[0017] According to a second embodiment, the airflow obstruction is placed on the outside of the casing between the first and second set of openings such that the airflow is obstructed at the second set of external cooling channels, such that the airflow is directed tangentially around the motor and towards an air gap between the rotor andthe stator of the permanent-magnet motor when housed, the air gap again extending axially between the first and second set of openings.

[0018] According to both embodiments, the air flow will be forced to flow through the air gap between the stator and the rotor of the permanent-magnet motor, which provides efficient cooling around and of the rotor. In other words, the air flow will flow axially between the stator and the rotor.

[0019] Using this housing according to these embodiments, the permanent-magnet motor can then be cooled according to different methods. With the two sets of openings, the cooling channels, the diversion channel, and the airflow obstruction, different configurations are then possible to cool the motor. According to a second aspect of the invention, methods are also disclosed for cooling a permanent-magnet motor using the housing according to the first aspect of the invention.

[0020] During the driving of the impeller of the air blower by the permanent-magnet motor, the rotor of the machine will have a higher temperature than stationary parts of the air blower. However, with housings and methods as known in the state of the art, it is not possible to cool this rotor directly. As will be discussed further, it is therefore an advantage of the present invention that the permanent-magnet motor can be cooled directly and therefore efficiently.

[0021] A first method of cooling a permanent-magnet motor, configured to drive an impeller of an air blower using the housing according to the first aspect of the invention comprises the steps of:- providing a first air flow at a first opening of the first set of openings;- diverting the first air flow at the opening opposite the first opening using and according to the diversion channel;- providing a second air flow at a first opening of the second set of openings;- obstructing the second airflow using and according to the airflow obstruction; wherein the openings of the second set of openings are located on a side away from the impeller when assembled, and wherein the power to provide the second airflow is greater than the power to provide the first airflow.

[0022] To implement this method, the airflow obstruction is placed on the outside of the casing at one opening of the second set of openings such that the airflow is forced towards the air gap between the rotor and the stator of the permanent-magnet motor when housed.

[0023] The first air flow is provided by a first fan, and the second air flow is provided by a second fan. The first air flow is then blown into an opening of the first set of openings by the fan. This air flow is then diverted by means of the diversion channel to the set of cooling channels that guide the air flow radially from the outside of the casing tothe inside. When guided to the inside, the air flow then flows to the first set of cooling channels to then let the air flow flow tangentially and axially, i.e. around the rotor of the permanent-magnet motor. Furthermore, this first air flow from the first fan will leave the casing along the second set of cooling channels on the side opposite to the one where the diversion channel is located. Simultaneously, a second air flow is provided at an opening of the second set of openings by means of a second fan. The second air flow then flows towards this opening, whereby the airflow obstruction forces this second air flow to flow axially along the rotor of the permanent-magnet motor to the opening of the first set of openings through the air gap between the stator and the rotor. This second air flow then connects with the first air flow and then also follows the path as described above.

[0024] It should be further understood that the set of cooling channels between the first and second set of openings on either side of a casing may include an opening from which conduits pass to and around the engine.

[0025] Furthermore, the power to provide the second airflow is greater than the power to provide the first airflow when the second set of openings is located on a side away from the impeller when assembled. In other words, when the housing comprises a permanent-magnet motor and the housing is further assembled with an impeller to form an air blower, the second fan is more powerful in power than the first fan. For example, to illustrate, the second fan has a power of 800W and the first fan has a power of 600W. It should be noted, however, that other values are also possible, and may depend on the power of the permanent-magnet motor and therefore also of the air blower.

[0026] The air flows described above can then be provided in different ways. Preferably, the direction of the first air flow is parallel to that of the second air flow, and even more preferably, the senso is also the same.

[0027] A second method of cooling a permanent-magnet motor, configured to drive an impeller of an air blower using the housing according to the first aspect of the invention comprises the steps of:- providing a first air flow at the second set of cooling channels;- diverting the first air flow to an opening of the first set of openings using the diversion channel;- providing a second air flow at an opening of the second set of openings;- obstructing the second air flow using and according to the air flow obstruction; and wherein the opening of the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the second airflow is greater than the power to provide the first airflow.

[0028] To apply this method, the airflow obstruction is placed just as in the previous method, hence on the outside of the casing at an opening of the second set of openings such that the airflow is directed towards the air gap between the rotor and the stator of the permanent-magnet motor when housed

[0029] Also according to this method, the first air flow is provided by a first fan, and the second air flow by a second fan. In this case, the first fan is placed between the two sets of openings and directed towards the second set of cooling channels. As a result, the air is then blown radially into the casing through the cooling channels of the second set of cooling channels, to then be guided tangentially and axially around the rotor via the cooling channels of the first set. Simultaneously, a second air flow is provided at an opening of the second set of openings, and the second air flow is obstructed by means of and according to the air obstruction. This means that the second air flow is forced to flow through the air gap between the rotor and the stator in the axial direction, and this from the opening of the second set to the opening of the first set. When assembled in the housing, the second set of openings is located away from the impeller, and the first set of openings is therefore located next to the impeller. Furthermore, the power to supply the second airflow is greater than the one to supply the first airflow. This then forces the airflows through the diversion channel and the air obstruction to the first set of openings where the air that has absorbed heat then leaves the housing.

[0030] Preferably, with this method, the directions of the first and second air flows are parallel, but the senses are opposite.

[0031] A third method of cooling a permanent-magnet motor, configured to drive an impeller of an air blower using the housing according to the first aspect of the invention comprises the steps of:- providing a first air flow to the second set of cooling channels;- diverting the first air flow to an opening of the second set of openings using the diversion channel;- obstructing the diverted first airflow at the opening opposite the opening of the second set of openings using and according to the airflow obstruction;- providing a second air flow at an opening of the first set of openings; and wherein the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the first airflow is greater than the power to provide the second airflow.

[0032] Again, the first air flow is provided by a first fan, and the second air flow by a second fan. Here, the first fan is placed between the two sets of openings and is directed towards the cooling channels of the second set. In this method, this first air flow is diverted to an opening of the second set of openings using the diversion channel that is located on the other side of the casing from the side where the first air flow isblown between the openings in the cooling channels. Note that the diversion channel here is located between the middle of the two sets of openings and the second set of openings. In this second set of openings, in addition to the diversion channel, the air flow obstruction is also located on an opposite side. The diverted air is therefore obstructed and forced towards the air gap between the rotor and the stator towards the first set of openings. A second air flow is then provided at an opening of the first set of openings by the second fan. This second air flow then flows transversely to the axial direction of the rotor when housed and then provides partial suction of the air flow originating from the first fan.

[0033] Preferably, in the method just discussed, the direction of the second air flow is parallel to that of the first air flow and the sense is opposite.

[0034] A fourth method of cooling a permanent-magnet motor, configured to drive an impeller of an air blower using the housing according to the first aspect of the invention comprises the steps of:- providing a first air flow at an opening of the first set of openings;- providing a second air flow at an opening of the second set of openings;- diverting the second air flow using and according to the diversion channel;- obstructing the diverted second airflow using and according to the airflow obstruction; wherein the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the second airflow is greater than the power to provide the first airflow.

[0035] As with the previous methods, the first air flow is provided by a first fan. This blows air into an opening of the first set of openings. Simultaneously, a second fan blows air into an opening of the second set of openings. This second air flow is then diverted from the opposite opening of this to the cooling channels of the second set. On the other side of the casing along which the second air flow is diverted, the air flow obstruction is then located. This then forces this diverted air flow to flow into an air gap between the rotor and the stator of the permanent-magnet motor when housed in the axial direction towards the first set of openings. Furthermore, a suction will be created by the first air flow to circulate the air flows around the rotor to cool it. Furthermore, the second set of openings is located on the side away from the impeller when assembled, and the power to provide the second air flow is greater than the power to provide the first air flow.

[0036] Preferably, in the method just discussed, the direction of the second air flow is parallel to that of the first air flow and the sense is opposite.

[0037] It should be further noted that the airflow obstruction, used in the methods discussed above, restricts the air at a predefined value, and that this value can be greater than 100 mbar, but other values are also possible.

[0038] According to a final embodiment, there is disclosed a method of cooling a permanent-magnet motor, configured to drive an impeller of an air blower using the housing according to the first aspect of the invention, the method, comprising the steps of:- providing a first air flow at an opening of the first set of openings;- providing a second air flow at an opening of the second set of openings;- providing a third air flow at the second set of cooling channels;- obstructing the second airflow using and according to the airflow obstruction; wherein the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the second airflow is greater than the power to provide the first airflow.

[0039] According to a third aspect, there is disclosed a blower, comprising the housing according to the first aspect of the invention, and a permanent-magnet motor, configured to drive the impeller of the blower housed therein.

[0040] According to an embodiment, the blower further comprises a first fan at the first opening, and a second fan at the second opening, the fans configured to perform one of the methods of the second aspect of the invention.

[0041] According to an embodiment, the blower further comprises an exhaust channel for exhausting the air flows, the exhaust channel being located at an opening different from that where the diversion channel is located.Short description of the drawings

[0042] The invention will be further illustrated with reference to the figures, in which

[0043] Fig. 1 illustrates a blower according to an embodiment of the invention;

[0044] Fig. 2 schematically illustrates a blower, comprising a cylindrical cavity for housing a permanent-magnet motor and indicating air flow paths to illustrate a first method of cooling the permanent-magnet motor when housed therein;

[0045] Fig. 3 schematically illustrates a blower, comprising a cylindrical cavity for housing a permanent-magnet motor and indicating air flow paths to illustrate a second method of cooling the permanent-magnet motor when housed therein;

[0046] Fig. 4 schematically illustrates a blower, comprising a cylindrical cavity for housing a permanent-magnet motor and indicating air flow paths to illustrate a third method of cooling the permanent-magnet motor when housed therein;

[0047] Fig. 5 schematically illustrates a blower, comprising a cylindrical cavity for housing a permanent-magnet motor and indicating air flow paths to illustrate a fourth method of cooling the permanent-magnet motor when housed therein.

[0048] Fig. 6 schematically illustrates a blower, comprising a cylindrical cavity for housing a permanent-magnet motor and indicating air flow paths to illustrate a fifth method of cooling the permanent-magnet motor when housed therein.Detailed description of the embodiments

[0049] The present invention will be described with reference to certain embodiments and with reference to certain drawings, but the invention is not limited thereto and is defined solely by the claims. The drawings described are only schematic and non- restrictive. In the drawings, the size of certain elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and relative sizes do not necessarily correspond to actual practical embodiments of the invention.

[0050] Furthermore, the terms first, second, third and the like are used in the specification and in the claims to distinguish between like elements and not necessarily to describe a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the invention may be practiced in sequences other than those described or illustrated herein.

[0051] Furthermore, the terms above, below, over, under and the like are used in the specification and claims for illustrative purposes and not necessarily to describe relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein may be practiced in orientations other than those described or illustrated herein.

[0052] Furthermore, the various embodiments, although referred to as “preferred embodiments”, should be construed as exemplary of how the invention may be practiced rather than as a limitation on the scope of the invention.

[0053] The term “comprising” as used in the claims, shall not be construed as being limited to the means or steps listed thereafter; the term shall not exclude other elements or steps. The term shall be construed as specifying the presence of the named features, elements, steps or components referred to, but shall not exclude the presence or addition of one or more other features, elements, steps or components, or groups thereof. The scope of the expression “a device comprising means A and B” shall thus not be limited to devices consisting only of components A and B. The meaning is that, with respect to the present invention, only components A and B of the device are listed, and the claim shall further be construed as including equivalents of these components.

[0054] Furthermore, the invention is discussed with reference to fans and / or airflows. Since the airflows are provided by the fans, these references are interchangeable. In other words, references that refer to fans can also refer to airflows and vice versa.

[0055] Fig. 1 illustrates a blower according to an embodiment of the invention. This blower 100 comprises a housing, configured to house a permanent-magnet motor. A blower 100 is a machine in which energy is exchanged between a flow of a fluid and a blade system that performs a rotary movement, in this case an impeller. The impeller is located inside the blower 100 and ensures that compressed air is made available at the outlet 101 of the blower 100. For this purpose, a motor is used to drive the impeller, which, according to this illustrated embodiment, is a permanent-magnet motor. During its operation, i.e. when the permanent-magnet motor drives the impeller, the motor will heat up. In order to ensure proper operation, this motor must be cooled. For this purpose, two fans 103 and 104 are used which, in combination with the housing and with the methods as will be discussed further, cool the rotor and stator of the motor. Furthermore, there is also an exhaust 102 to discharge the air in which heat has been absorbed. Finally, in Fig. 1 a diversion channel 105 is illustrated which, in combination with the openings, cooling channels, air gap, and air flow obstruction, ensures that the cooling can take place efficiently. This is discussed further with reference to Figs. 2 to 6.

[0056] In Figs. 2 to 6, methods are illustrated for cooling the permanent-magnet motor when active and housed in the blower 100. With reference to Fig. 2, there is illustrated a cylindrical cavity 211 for housing the permanent- magnet motor. The rotor is located in this cavity and the stator 212 is located around the rotor. Reference numeral 210 designates the location of the impeller driven by the permanent-magnet motor. Further, reference numeral 213 designates the location that is referred to as the first set of openings, and reference numeral 214 that is referred to as the second set of openings. It will be noted that the first set of openings 213 is located on the side near the impeller, and the second set of openings 214 is located away from the side of the impeller. Further, solid arrows and dotted arrows have been noted in the illustrations of Figs. 2 to 6. The solid arrows refer to the first air flow as discussed further, while the arrows drawn with a dotted line refer to the second air flow. This is true for each of Figs. 2 to 6.

[0057] With reference again only to Fig. 2, there is a first fan 201 providing the first air flow, thus indicated by the solid arrows, and a second fan 202 providing the second air flow indicated by the dotted arrows. The first air flow is blown through an opening of the first set of openings 213 and is guided via the diversion channel illustrated by reference numeral 203 to the outer casing of the housing, along the cooling channels of the second set, around the motor, to then exit the housing again, indicated by referencenumeral 206. Furthermore, the second fan 202 provides the second air flow to an opening of the second set of openings 214. Opposite this fan 202, there is an air flow obstruction indicated by reference numeral 204. Reference numeral 205 indicates that a fraction of the air flow is allowed to pass, but that the major part of the air flow is obstructed. This obstruction causes the second air flow to be forced to flow through the air gap between the rotor and the stator, illustrated by reference numeral 207. The air flow then continues to the opening of the first set of openings 213 and joins the first air flow. Note further that the power of the second fan 202 in this method is greater than the power of the first fan 201. For example, the second fan 202 has a power of 800W, and the first fan 201 has a power of 600W, for example. The powers mentioned here as examples can also be used for the methods illustrated in Figs. 3 to 6.

[0058] In Fig. 3, a second method of cooling the permanent-magnet motor is illustrated.According to this method, the first fan 301 is located on the outer casing of the housing to blow the first air flow through the cooling channels of the second set. These then run radially to the inside, around the motor via the cooling channels of the first set, and then through the casing back to the outside opposite the first fan 301. The first air flow is then diverted 303 by the diversion channel to the first set of openings. Furthermore, there is provided a second fan 302 with a higher power than the first fan 301 which blows a second air flow into an opening of the second set of openings. Opposite this the air flow obstruction 304 is located which partially obstructs this blown air, causing the major part to run axially and tangentially along the air gap 306 to then connect with the first air flow, and to leave the housing via 305.

[0059] In the method illustrated in Fig. 4, the first air flow is blown by the first fan 401 into an opening of the first set of openings, and the second air flow is blown by the second fan 402 into an opening of the second set of openings. Here, the power to provide the second air flow is greater than the one to provide the first air flow. The second air flow is then diverted 404 from the opening of the second set of openings to the outer casing, and more specifically to the cooling channels of the second set. Furthermore, the air flow obstruction 403 is also placed on this outer casing such that the second air flow is further forced towards the air gap 406 between the rotor and the stator, to then join the first air flow. The first and the second air flow then leave the housing at reference numeral 405.

[0060] In Fig. 5, a final method of cooling the permanent-magnet motor using the housing is illustrated. The fan 501 blows the first air flow into an opening of the first set of openings, and the fan 502 blows the second air flow at a higher power than the first air flow at the outer casing through the air channels of the second set. The second air flow passes through the casing and is diverted 505 to an opening of the second set of openings, where the air flow obstruction 503 is then further located to force the airflow towards the air gap 506 to join the first air flow and exit the housing at location 504.

[0061] Finally, there is a method as illustrated in Fig. 6 in which three fans 601-603 are used to cool the engine. In this method, an air flow is blown by fan 601 into an opening of the first set of openings. An air flow is blown by fan 602 into the second set of cooling channels. Finally, a third air flow is blown by fan 603 into an opening of the second set of openings. Depending on the orientation of the fans, and therefore the direction and sense of the various air flows, there may be a diversion channel to divert one of the air flows. Furthermore, there is an air flow obstruction 604 at an opening of the second set of openings, whereby the air flow 605 is forced to flow axially and tangentially along the rotor. Finally, the air flows, which are then partly a combination of the various air flows, leave the casing via 606 and 607.

Claims

Claims

1. - A housing, configured to provide an air cooling to a permanentmagnet motor, comprising a stator and a rotor, configured to drive an impeller (210) of an air blower (101) to be provided with an air cooling, the housing comprising a cylindrical cavity (211), configured to house the permanent-magnet motor, and further comprising a casing, comprising:- a first set (213) and a second set (214) of opposed openings at the first and second end of the cavity (211), respectively, the set of openings (213, 214) configured to direct an airflow radially from the outside of the casing towards the rotor of the permanent-magnet motor when housed;- a first set of cooling channels between and connected to the set of openings (213, 214) on the rotor and configured to direct the airflow axially around the permanent-magnet motor when housed;- a second set of cooling channels connected to the first set of cooling channels, configured to direct airflow radially from the outside of the casing to said first set; wherein the housing further comprises a diversion channel (105) on the outside of the casing, configured to direct airflow between an opening of the first (213) or second (214) set of openings on one side and the second set of cooling channels on the other side.

2. The housing of claim 1, the casing further comprising an airflow obstruction (204, 503), configured to obstruct a flow-through of the airflow under a predefined pressure, the airflow obstruction (204, 503) disposed on the outside of the casing at an opening of the first (213) or second (214) set of openings such that air is forced into an air gap (207, 506) between the rotor and the stator of the permanent-magnet motor when housed, the air gap (207, 506) extending axially between the first (213) and second (214) sets of openings.

3. The housing of claim 1, the casing further comprising an airflow obstruction (403), configured to obstruct a flow-through of the airflow under a predefined pressure, the airflow obstruction (403) disposed on the outside of the casing between the first (213) andsecond (214) set of openings such that the air flow to the second set of outside cooling channels is obstructed, such that air flow is directed tangentially around the motor and towards an air gap (406) between the rotor and stator of the permanent-magnet motor when housed, the air gap (406) extending axially between the first and second set of openings.

4. The housing according to any one of claims 2 to 3, wherein the predefined pressure at which the airflow obstruction obstructs the airflow, is greater than 100 mbar.

5. - A method of cooling a permanent-magnet motor, configured to drive an impeller (210) of an air blower (100) using the housing of claim 2, the method comprising the steps of:- providing a first air flow (201) at a first opening of the first set of openings;- diverting (203) the first air flow (201) at the opening opposite the first opening using and according to the diversion channel (203);- providing a second air flow (202) at a first opening of the second set of openings;- obstructing (204, 205) the second air flow (202) using and according to the air flow obstruction (204, 205); wherein the openings of the second set of openings are located on a side away from the impeller when assembled, and wherein the power to provide the second airflow (202) is greater than the power to provide the first airflow (201).

6. A method of cooling a permanent-magnet motor, configured to drive an impeller (210) of an air blower (100) using the housing of claim 2, the method comprising the steps of:- providing a first air flow (301) at the second set of cooling channels;- diverting (303) the first air flow (301) to an opening of the first set of openings using the diversion channel (303);- providing a second air flow (302) at an opening of the second set of openings;- obstructing the second air flow (302) using and according to the air flow obstruction (304); andwherein the opening of the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the second airflow (302) is greater than the power to provide the first airflow (301).

7. - A method of cooling a permanent-magnet motor, configured to drive an impeller (210) of an air blower (100) using the housing of claim 2, the method comprising the steps of:- providing a first air flow (502) at the second set of cooling channels;- diverting (505) the first air flow (502) to an opening of the second set of openings using the diversion channel (505);- obstructing the diverted first air flow (502) at the opening opposite the opening of the second set of openings using and according to the air flow obstruction (503);- providing a second air flow (501) at an opening of the first set of openings; and wherein the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the first airflow (502) is greater than the power to provide the second airflow (501).

8. - A method of cooling a permanent-magnet motor, configured to drive an impeller (210) of an air blower (100) using the housing of claim 3, the method comprising the steps of:- providing a first air flow (401) at an opening of the first set of openings;- providing a second air flow (402) at an opening of the second set of openings;- diverting (404) the second air flow (402) using and according to the diversion channel (404);- obstructing the diverted second airflow (402) using and according to the airflow obstruction (403); wherein the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the second airflow (402) is greater than the power to provide the first airflow (401).

9. The method according to any one of claims 5 to 8, wherein the direction of the first air flow (201, 301, 401, 501) is the same as the direction of the second air flow (202, 302, 402, 502).

10. The method according to claim 9, wherein the sense of the first air flow (201, 301, 401, 501) is equal to the sense of the second air flow (202, 302, 402, 502).

11. The method according to claim 9, wherein the sense of the first air flow (201, 301, 401, 501) is opposite to the sense of the second air flow (202, 302, 402, 502).

12. - A method of cooling a permanent-magnet motor, configured to drive an impeller (210) of an air blower (100) using the housing of claim 2, the method comprising the steps of:- providing a first air flow (601) at an opening of the first set of openings;- providing a second air flow (603) at an opening of the second set of openings;- providing a third air flow (602) at the second set of cooling channels;- obstructing the second air flow (603) using and according to the air flow obstruction (604); wherein the second set of openings is located on a side away from the impeller when assembled, and wherein the power to provide the second airflow (402) is greater than the power to provide the first airflow (401).

13. - A blower (100), comprising the housing of any one of claims1 to 4, and a permanent-magnet motor, configured to drive the impeller of the blower (100) housed therein.

14. The blower (100) of claim 13, further comprising a first fan (201,301, 401, 501) at an opening of the first set of openings, and a second fan (202, 302, 402, 502) at an opening of the second set of openings, the fans configured to provide airflows according to any one of the methods of any one of claims 5 to 10.

15. - The blower (100) according to any one of claims 13 to 14, further comprising an exhaust channel (206, 305, 405, 504) for exhausting the air flows, wherein the exhaust channel is locatedat an opening different from that where the diversion channel is located.HOUSING FOR PROVIDING A PERMANENT-MAGNETMOTOR OF AN AIR BLOWER WITH AN AIR COOLING

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