Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/27—Rotor cores with permanent magnets
  • H02K1/2793—Rotors axially facing stators
  • H02K1/2795—Rotors axially facing stators the rotor consisting of two or more circumferentially positioned magnets
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/28—Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
  • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
  • H02K21/24—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets axially facing the armatures, e.g. hub-type cycle dynamos
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/02—Arrangements for cooling or ventilating by ambient air flowing through the machine
  • H02K9/04—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K9/00—Arrangements for cooling or ventilating
  • H02K9/02—Arrangements for cooling or ventilating by ambient air flowing through the machine
  • H02K9/04—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium
  • H02K9/06—Arrangements for cooling or ventilating by ambient air flowing through the machine having means for generating a flow of cooling medium with fans or impellers driven by the machine shaft

Definitions

• the object of the present invention is a so-called axial-flux electric motor, i.e. an electric motor with a relative arrangement of its stator and rotor such that the magnetic circulation is determined according to a peculiar spatial/volumetric pattern that is quite different from more traditional radialflux electric motors; such a motor may be used in various application fields such as (but not limited to) portable agricultural machinery as shakers and the like.
• axial-flux electric motors consist of two elements: a “stationary” one (the stator) and a “moving” one (the rotor) which generally rotates relative to the stationary element.
• the rotation effect of the rotor is suitably induced by powering the stator in such a way that it produces a variable electromagnetic field, which in turn induces suitable phenomena in the rotor leading to the onset of a magnetic field (induced, in fact) that exerts suitable forces/torques on the rotor itself.
• axial-flux used to define this type of electric motor derives from the fact that the lines of the resulting magnetic field that develop in the motor during its operation have a significant geometric/topological component developing parallel to the rotation axis of the rotor, and thus “longitudinally” relative to the development of the entire motor along such rotation axis: such geometry is in turn a result of the peculiar arrangement of the magnetically active elements of the rotor relative to those of the stator, and by virtue of this peculiarity, axial-flux electric motors may generally offer a higher motor torque output (compared to radial-flux electric motors) and have a particularly small longitudinal size.
• axial-flux electric motors of the known type are not free from drawbacks and criticalities, both from a manufacturing and engineering perspective.
• the object of the present invention is to manufacture an axial-flux electric motor which is capable of overcoming the drawbacks just mentioned, and which in particular is capable of ensuring a rapid and robust fastening of the magnetically active elements (e.g., permanent magnets) on the rotor while minimising the number of necessary components and screws, and at the same time ensuring an optimal design of the magnetic profiles of the motor (thereby maximising its performance in terms of at least the maximum torque that can be output and/or the minimum electrical current absorption to produce such maximum torque).
• the magnetically active elements e.g., permanent magnets
• Fig. 1 shows an exploded perspective view of an axial-flux electric motor according to the invention
• Fig. 2 shows a perspective view of a rotor of the electric motor in Figure 1 ;
• Fig. 3 shows a sectioned perspective view of the rotor along track III - Ill in Figure 2;
• Fig. 4 shows a detailed perspective view of a magnetically active element that can be associated with the rotor in Figures 2 and 3.
• the axial-flux electric motor according to the invention is generally denoted by number (1) and basically comprises a rotor (2), a stator (3) circumscribed to the rotor (2) (therefore the rotor (2) is rotatably engaged to the stator (3)) and suitable power means that are active on the rotor (2) and/or the stator (3) to induce a rotation of the rotor (2) relative to the stator (3).
• the rotor (2) comprises a rotor plate (4), which is designed to house a plurality of magnetically active elements (5) angularly equally-spaced in the rotor plate (4), and in particular comprises coronal retaining means: said coronal retaining means are connected to the rotor plate (4) and are shaped and arranged to rest on the magnetically active elements (5) along a minimum circumference (6) and/or along a maximum circumference (7).
• the coronal retaining means are arranged, structurally and functionally, in such a way that the magnetically active elements (5) are positioned - and thus stably retained in their position even during highspeed rotations of the rotor (2) - within the minimum (6) and maximum (7) circumferences; this peculiar constraint insisting between the rotor plate (4) and the magnetically active elements (5) makes the entire rotor assembly (2) very efficient and at the same time extremely simplified, and allows the magnetically active elements (5) to be shaped according to geometries or volumes that do not compromise their efficiency in terms of the resulting magnetic flux during the motor (1) operation.
• the minimum circumference (6) and/or the maximum circumference (7) protrude from the rotor plate (4) and respectively define at least one perimeter undercut (which, for the sake of clarity of disclosure, may be defined as “inner coronal undercut” and “outer coronal undercut”), which in turn is designed to rest on suitable edges of the magnetically active elements (5), as will be seen below.
• each perimeter/coronal undercut inner and/or outer continuously extends either along the minimum circumference (6) or along the maximum circumference (7): this makes it possible to obtain, on the one hand, an exceptional geometric regularity of the rotor components and, on the other hand, to install magnetically active elements (5) having different dimensions in terms of “width”.
• the aforementioned discoidal element (8) also includes reversible active constraining means (9) between the discoidal element (8) itself and the rotor plate (4), so as to allow a correct insertion and assembly of the magnetically active elements (5).
• the above-mentioned reversible constraining means (9) may comprise suitable mechanical devices, also of the known type: for example, this may be a predetermined number of screws that are radially equally-spaced relative to the rotation axis of the rotor (2) (referring to a rotation axis of the rotor (2), in the language of the invention, as an axis placed at said central portion of the rotor (2) itself).
• the maximum circumference (7) integrally extends from the rotor plate (4) and typically develops at a maximum diameter of the rotor (2) relative to its rotation axis: the fact that the maximum circumference (7) is made in a “single piece” or integrally, as you may call it, greatly simplifies the construction of the rotor (2) and implements a considerable degree of retention and holding in position of the magnetically active elements (5), even opposing very high centrifugal forces and thus making it possible to achieve a higher rotational speed for the entire axial-flux electric motor (1) according to the invention.
• the magnetically active elements (5) comprise prismatic bodies perimetrically defined by the following set of sides: - an inner edge (5a) counter-shaped to the undercut defined by the inner circumference (6);
• the inner edge (5a) and the undercut (inner coronal) defined by the inner circumference (6) have a mutually counter-shaped geometric pattern: this geometric pattern, when viewed “in section” may conveniently comprise one or more rectilinear and/or curvilinear segments that are mutually complementary in the motor (1) assembled conditions.
• outer edge (5c) and the (outer coronal) undercut defined by the outer circumference (7) have a mutually counter-shaped geometric pattern which, when still viewed “in section”, may comprise one or more mutually complementary curvilinear segments in the motor (1) assembled condition.
• ventilation vanes (10) which may project from one or both faces of the rotor plate (4): these ventilation vanes (10) may be integrally formed in a single piece with the rotor plate (4) or may be connected to and/or mounted on the rotor plate (4) itself by means of suitable mechanical constraints, as illustrated in Figure 1.
• a machinery or device which, by way of a non-limiting example, may be a portable agricultural tool, which comprises at least one drive unit as well as at least one operating tool moved by said drive unit: advantageously, said drive unit comprises at least one axial-flux electric motor according to the foregoing and/or according to what hereinafter claimed.
• the invention allows to obtain important advantages.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Permanent Magnet Type Synchronous Machine (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=84604124

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Family Cites Families (6)

• 2022
  • 2022-10-25 WO PCT/IT2022/000054 patent/WO2024089715A1/en not_active Ceased
  • 2022-10-25 KR KR1020257011022A patent/KR20250097803A/ko active Pending
  • 2022-10-25 EP EP22830314.5A patent/EP4609490A1/de active Pending

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