Compact two-phase motor

Abstract

The invention relates to a two-phase brushless motor consisting of a rotor (10) and a stator (20) consisting of a stack of cut ferromagnetic laminations having two teeth (21, 22), each tooth extending along an intermediate radial axis (A1, A2), the intermediate radial axes (A1, A2) being coplanar, the cross-section of the stator being inscribed within a rectangle of length L1 and width L2, the invention relates to a two-phase brushless motor comprising a rotor (10) comprising three, four or five pairs of magnetic poles radially magnetized in alternating directions, each of the teeth (21, 22) being surrounded by a coil (31, 32), characterized in that the intermediate radial axes (A1, A2) form therebetween an angular sector (alpha1) extending within an angle of between 145 DEG and 180 DEG, and the stator (20) has at least one mechanical and magnetic continuation (41, 42) extending between the two winding teeth (21, 22).

Description

Technical Field

[0001] The present invention relates to a two-phase brushless motor, and more particularly, to a motor integrated into an electromechanical system. More specifically, the present invention relates to automotive peripherals with very compact space constraints, such as the actuation of an expansion valve or an air flow diverter vane in an air conditioning module. Background Art

[0002] An example of such a motor is described in the applicant's patent FR2742940B1, which proposes a two-phase motor including a stator part excited by two electric coils and a magnetized rotor having N (N equal to 3 or 5) pairs of magnetic poles magnetized in alternating directions radially. The stator section is characterized by at least two W-shaped circuits, each W-shaped circuit having an electric coil around a central leg. The W-shaped circuits are arranged such that when one of the central legs faces a magnetic transition, the other central leg faces a magnetic pole. The pole shoes of the legs of the W-circuit are angularly spaced by π / 4, and the pole shoes of the central legs of two W-circuits belonging to different phases are angularly spaced by an angle substantially equal to π / 2 ± k.π / N, where N is the number of pairs of magnetic poles, 3 or 5, and k is equal to 0, 1, or 2.

[0003] For example, other similar motors are known from patent EP1713166, which describes a drive device including a stator, a rotor, and a magnet. The rotor includes a core formed of a soft magnetic material and a shaft mounted in the core. The magnet has a cylindrical shape and is magnetized such that different poles alternate in the circumferential direction. At an axial position between the magnet and the base, a first coil is wound around the first outer magnetic pole portion via the coil. At an axial position between the magnet and the base, a second coil is wound around the second outer magnetic pole portion via the coil.

[0004] The needle valve described in patent EP2484948A1 includes: a housing formed with a first port communicating with one end portion of a cylindrical communication hole and a second port communicating with the other end portion of the communication hole; a needle valve stem movably mounted in the communication hole in the axial direction and formed with a tapered portion whose outer diameter varies in a direction from one end portion side of the communication hole toward the other end portion side, and the gap between the tapered portion and the valve seat surface of the communication hole varies according to the axial position of the needle valve stem.

[0005] Patent US2017338113 describes an electric motor that includes a stator and a rotor rotatably disposed within the stator. The rotor includes a rotatable shaft and a gearbox driven by the electric motor. The gearbox includes a housing in which the electric motor is mounted and a gear mounted on the housing and driven by the rotatable shaft of the electric motor. Two first bearings are mounted on the same side of the stator within the housing to support the rotatable shaft and to allow the stator to pivot relative to the housing.

[0006] Disadvantages of the prior art

[0007] It is obvious that the various geometries proposed in the prior art have led to solutions that are adversely affected by a relatively high residual no-current torque C0 for a given power and the occupied area in one direction in a plane perpendicular to the axis of rotation, which can be improved and limited. Specifically, the prior art solutions characterized by a "W" - shaped magnetic circuit are unsatisfactory in terms of no-current torque only when the winding teeth form an angle exceeding 120° and their magnetic circuits are magnetically connected, resulting in an interaction between these magnetic circuits that adversely affects the no-current torque.

[0008] Some prior art solutions also have the disadvantage of requiring complex stator shapes that are not compatible with conventional techniques for stacking thin ferromagnetic laminations, such as expensive 3D lamination forming or multi - part assembly. Summary of the invention

[0009] The present invention aims to solve these disadvantages. To this end, the present invention, in its broadest scope, relates to a two - phase brushless motor having the features according to claim 1.

[0010] The two - phase brushless motor consists of a rotor and a stator. The stator consists of a stack of cut ferromagnetic laminations having two teeth, each tooth extending along a middle radial axis, the middle radial axes being coplanar. The cross - section of the stator is inscribed in a rectangle having a length L1 and a width L2. Each of the teeth is surrounded by a coil. The rotor includes three, four, or five pairs of magnetic poles magnetized radially in alternating directions. The two - phase brushless motor is characterized in that the middle radial axes extend within an angular sector in which the angle formed therebetween is greater than 145° and less than 180°, and the stator has at least one mechanically and magnetically continuous portion extending between two wound teeth.

[0011] The object of the present invention may also have one or a compatible combination of the following features.

[0012] Specifically, the middle radial axes form an angle of 157.5° with each other, and the rotor has 4 pairs of poles.

[0013] Alternatively, the middle radial axes form an angle of 162° with each other, and the rotor has 5 pairs of poles.

[0014] In another alternative, the intermediate radial axes form an angle with each other such that the two coils are electrically phase-shifted by 120°.

[0015] In a first variant, the yoke has a second mechanical and magnetic continuity section, and one or the other of the mechanical and magnetic continuity sections forms at least one continuous unwound tooth. The first mechanical and magnetic continuity section and the second mechanical and magnetic continuity section extend between two wound teeth on either side of the rotor, and the first mechanical and magnetic continuity section and the second mechanical and magnetic continuity section have different angular widths.

[0016] Specifically, for this first variant, the second mechanical and magnetic continuity section of the mechanical and magnetic continuity sections forms a single continuous unwound tooth.

[0017] According to this variant, the intermediate radial axis of each of the one or more continuous unwound teeth can be positioned equidistantly from the intermediate radial axis.

[0018] Furthermore, according to this variant, the angular width of the one or more continuous unwound teeth can be between 60° and 130°.

[0019] In another variant, the mechanical and magnetic continuity section forms two unwound teeth, and the intermediate radial axis of each of the unwound teeth forms an angle greater than 45° with the intermediate radial axis of the nearest wound tooth.

[0020] In another variant, the mechanical and magnetic continuity section forming two unwound teeth is located in the minimum extended angular sector that separates the intermediate radial axes.

[0021] Alternatively, the yoke has a discontinuity on the side opposite the mechanical and magnetic continuity section that extends between two wound teeth.

[0022] In another variant, the ratio between the diameter D and the length L1 of the rotor is greater than 50%.

[0023] In one variant, the ratio between the width L2 of the outer housing of the stator and the length L1 is between 0.4 and 0.6.

[0024] Specifically, the ratio between the width L2 of the outer housing of the stator and the length L1 is between 0.4 and 0.5.

[0025] In one variant, the rotor is coupled to a worm, and the worm forms the first module of a motion conversion system.

[0026] Specifically, the motion conversion has a rotational-linear type that controls the linear displacement of an output member.

[0027] More precisely, the member is a needle.

[0028] Alternatively, the movement transformation is a linear displacement collinear with the axis of the rotor.

[0029] In another alternative, the movement conversion has a rotation-rotation type that controls the rotation of the output shaft.

[0030] In a variant, the output shaft is oriented in a direction perpendicular to the axis of the rotor.

[0031] The present invention also relates to an electromechanical system comprising a brushless motor and a substantially parallelepiped housing, characterized in that the motor is identical to the motor according to one of the previous variants, and the axis of the rotor is oriented along the length of the long side of the parallelepiped housing defining the housing.

[0032] Specifically, the electromechanical system includes a printed circuit board arranged between the motor and the housing, and the face of the printed circuit board of the motor has a connector passing through a cutout provided in the lateral face of the housing. Description of the Drawings

[0033] The present invention will be better understood after reading the following description of non-limiting exemplary embodiments shown in the drawings, wherein:

[0034] Figure 1 shows a front view of a first example of a motor according to the present invention having 4 pairs of magnetizing poles,

[0035] Figure 2 shows a front view of a second example of a motor according to the present invention having 5 pairs of magnetizing poles,

[0036] Figure 3 shows a front view of a third example of a motor according to the present invention having magnetic and mechanical discontinuities,

[0037] Figure 4 shows a front view of a fourth example of a motor according to the present invention,

[0038] Figure 5 shows a front view of an example in which a motor according to the present invention is integrated in a gate motorized actuator, where the cover of the actuator housing is peeled off,

[0039] Figure 6 shows a cross-section orthogonal to the axis of the rotor of the actuator shown in the previous figure,

[0040] Figure 7 shows Figure 5 ​​​​​​​Cross-sectional view AA' of the actuator shown,

[0041] Figure 8 Front view showing an example of a motor integrated in an expansion valve actuator according to the present invention,

[0042] Figure 9 Lateral cross-sectional view of the actuator shown in the previous figure,

[0043] Figure 10 Shows a cross-section orthogonal to the rotor axis of the valve actuator shown in Figure 8 , where the covering of the housing is peeled off,

[0044] Figure 11 Perspective view showing a variant with two coupled stators. Detailed Description

[0045] The object of the present invention is to provide a two-phase electric motor that is easy to manufacture, has high performance and is compact. Specifically, the present invention relates to an electric motor having a form factor perpendicular to the axis of rotation of the rotor, which is optimized for integration into a compact housing, wherein the rotor axis is positioned perpendicular to the cross-sectional plane of the housing.

[0046] For certain electromechanical applications (louver actuators, fluid valves, etc.), the form factor required to optimally integrate the motor into the actuator housing means that, in the cross-section of the motor (orthogonal to its axis of rotation), the dimension along one axis is much smaller than the dimension along the other axis, resulting in a motor that is quite slender and has a generally tubular housing, but different from the prior art long-shaped motors in that the axis of rotation of the rotor is orthogonal to the long length of the housing and is located near the middle along that long length. Hereinafter, the motor width refers to the minimum motor dimension in the cross-section, the length refers to the maximum motor dimension in the cross-section, and the thickness refers to the dimension in the direction orthogonal to the cross-section.

[0047] In a specific application for automotive air conditioning fin control, the stator plane perpendicular to the axis of rotation is inscribed in the minimum cross-section of the actuator.

[0048] However, these dimensional constraints must maintain the performance of the motor in terms of torque and electromechanical efficiency, and this is achieved by reducing the residual torque in the absence of current observed in prior art solutions.

[0049] ​​​​To this end, the electric machine according to the invention comprises a stator having only two winding teeth, a first winding tooth carrying a first coil fed by a first phase, and a second winding tooth carrying a second coil fed by a relative phase of a two-phase power supply. When the rotor has 4 pole pairs, the angle formed between the intermediate radial axes of the two teeth is between 155° and 150°, or when the rotor has 5 pole pairs, this angle is between 160° and 165°, or the angle is such that the two coils are electrically out of phase by 120°.

[0050] Geometric features of the electric machine according to the invention

[0051] The two-phase electric motor (1) according to the invention comprises a rotor (10) and a stator (20), the stator being equipped with two coils (31, 32), each coil being connected to a different electric phase supplying said two-phase electric motor. The stator (20) is formed by a stack of ferromagnetic laminations, all the ferromagnetic laminations having the same cutouts and being symmetric with respect to a transverse intermediate plane P. Observed in the lamination plane, the laminations are provided with a closed peripheral band (40) (this peripheral band being inscribed in a rectangular housing (50) having a length L1 and a width L2), and having cutouts to form two teeth (21, 22) intended to carry the two electric coils (31, 32). These two teeth (21, 22) are radially oriented with respect to the rotor (10) and extend along two coplanar axes (A1, A2) angularly separated by an angle greater than 145°, so as to form two complementary angular sectors (α1, α2). In at least one of the angular sectors (α1, α2), the teeth (21, 22) are connected by the peripheral band so as to ensure at least a mechanical and magnetic continuity (41, 42) between the teeth (21, 22). The angular separation of the winding teeth (21, 22) at a very wide angle minimizes the radial occupancy of the stator in the angular sectors (α1, α2), within which the laminations are cut to ensure a strict minimum required for a good magnetic connection with the rotor and for guaranteeing the mechanical strength of the stator assembly.

[0052] The lamination plane of the laminations is the plane orthogonal to the thickness of the laminations, that is to say, the smallest dimension of the laminations before any cutting. The laminations are stacked in a direction orthogonal to this plane to form a stack of laminations.

[0053] The rotor (10) has a diameter D and is inscribed in a rectangular housing (50) of the stator laminations such that the ratio of the rotor diameter to the stator width is greater than 50%. The rotor has N magnetized poles (11, 12), where N is 6, 8 or 10, and these magnetized poles are distributed around its periphery in alternating directions to form north poles (11) and south poles (12). These poles are preferably produced in an integral magnetic ring molded onto a cylindrical core, but can alternatively be obtained by any other technique known to those skilled in the art, such as press - fit rings, bonded magnetized segments, or even, in a non - limiting manner, by magnetizing injected magnets that make up the integral rotor.

[0054] The lengths of the winding teeth (21, 22) are carefully chosen to be compatible with the construction of the electrical coils (32, 32) on the coil body, and then the coil body is inserted onto the teeth (21, 22) of the laminated core through an internal space that is released to accommodate the rotor (10). Thus, the length of the winding teeth (21, 22) must be less than the rotor diameter D plus twice the magnetic air gap e, which corresponds to the difference between the tooth faces (21, 22) and the outer periphery of the rotor.

[0055] First variant embodiment

[0056] Figure 1 A first variant example of the present invention with an 8 - pole magnetic rotor (11, 12) is shown. To optimize the magnetic performance, the axes (A1, A2) of the winding teeth (21, 22) are angularly separated by 157.5°, which is the maximum opening angle that allows perfect magnetic orthogonality between the winding teeth (21, 22). Thus, when one of the two teeth (21, 22) faces the transition between two magnetic poles (11, 12) of the rotor, the other tooth faces the middle of another magnetic pole. To ensure good magnetic flux feedback, the winding teeth (21, 22) are connected by mechanical and magnetic continuities (41, 42) in each of the angular sectors (α1, α2), and its cross - section w (that is, the thickness in the lamination plane of the laminations) must be sufficient to ensure that the magnetic flux passes through without saturation and is thus equal to half the width of the winding teeth (21, 22). This constraint defines the maximum overall dimensions of the stator and thus defines the length of the rectangular housing (50) as L1 and the width as L2.

[0057] These parameters can be written as a function of the motor size variables, which are given by the following:

[0058] L1 = 2×B1cos(90 - θ)+B2sin(90 - θ), and

[0059]

[0060] Where θ is half of the minimum angle between the axes (A1, A2), B1 is the length between the center of rotation of the rotor and the bottom of the winding teeth (21, 22), and B2 is the width of the bottom of the teeth. These last two values are written as:

[0061] And

[0062] B2 = 3×w + 2×l s ,

[0063] Where l s is the width of the winding slot and 1 is the length of the tooth, and there are the following constraints for coil insertion:

[0064] 1 ≤ D + 2×e.

[0065] The width of the teeth (21, 22) (i.e., 2×w) is preferably determined with respect to the opening angle P at the front of the teeth (21, 22), and the following relationship is given:

[0066]

[0067] Finally, the width l of the slot s is set by the end of the face of the nearest unwound tooth; the angle formed between the tooth center and this end is called γ, and we get:

[0068]

[0069] Preferably, the angles β and γ are selected such that:

[0070] 14° ≤ β ≤ 30°, and

[0071] 35° ≤ γ ≤ 65°,

[0072] And in order to conform to the following ratio:

[0073] And

[0074]

[0075] Compared with the prior art of an asymmetric two-phase motor with a preferred closing angle (usually equal to 90°), this construction has the following advantages: better balance of magnetic forces and thus limitation of vibrations related to the force variations between the rotor and the stator.

[0076] To minimize the no-current torque and, again, to minimize vibrations, the mechanical and magnetic continua (41, 42) each feature a projection that extends towards the rotor to form highly expanded un-wound teeth (23, 24), which are angularly expanded over most of the angular sectors (α1, α2), leaving only the space required for the slots that accommodate the electric coils (31, 32) supported by the teeth (21, 22). Since the angular sectors (α1, α2) have different widths, the faces of the un-wound teeth (23, 24) extend over different angular ranges greater than 60°, while the wound teeth (21, 22) instead have tooth faces that extend at an angle of 20°. The resulting two-phase motor has an almost smooth air gap that is only notched around the teeth (21, 22) to accommodate the coils (31, 32).

[0077] Note that this wide-tooth configuration allows for notching of the outer perimeter of the magnetic and mechanical continua (240) located in the most closed angular sector (α1). The resulting notches (43, 44) allow the stator (20) to be fixed without protruding beyond the rectangular housing (50), while leaving sufficient cross-section for the magnetic flux to pass through the magnetic and mechanical continua (41). The most open angular sector (α2) provides more space to ensure mechanical strength, but does not protrude beyond the rectangular housing (50), so that the second magnetic and mechanical continua (42) can have a larger cross-section and be provided with holes (47, 48) to ensure extremely precise positioning of the poles of the stator and its supports, while providing sufficient cross-section for the magnetic flux to pass through.

[0078] Of course, the 157.5° angle between the axes (A1, A2) of the wound teeth (21, 22) is optimal for two-phase control of the two coils. However, a person skilled in the art can envision modifying this angle for different purposes. For example, the angle can be slightly modified to intentionally reduce the magnetic performance in terms of torque density, but improve the no-current torque. Another alternative motivation would be to achieve a three-phase drive using only two coils. In fact, the two coils can be powered together to simulate the missing coil of a three-phase drive. The wound teeth (21, 22) must then be arranged such that a 120° electrical angle is obtained between the coils. This means that the voltage induced by the rotation of the rotor generates signals that are 120° out of phase at the terminals of the two windings. The angle between the axes (A1, A2) of the wound teeth (21, 22) would then be 165° in order to obtain optimal steering consistent with the present invention. Of course, the term three-phase control is misused, since the electrical vectors correspond to this type of control, but still within the framework of a two-phase motor powered by only two windings.

[0079] Second variant embodiment

[0080] Figure 2Shows a second variant according to the present invention. It differs from the previously designed one in that the rotor is equipped with 10 magnetic poles (11, 12). In order to keep the teeth (21, 22) wound in a phase-orthogonal manner, the angle between the axes (A1, A2) is increased to 162°. This configuration results in a motor that is flatter than the Figure 1 version with 8 magnetic poles (11, 12) shown.

[0081] As a direct result, the outer periphery of the magnetic and mechanical continuity part (41) located in the most closed corner sector (α1) is closer to the rotor. Therefore, the cross-section of the magnetic and mechanical continuity part (41) is smaller and no longer allows notches on its outer periphery, as shown in Figure 1 , but does not affect the passage of magnetic flux or have cylindrical attachment devices protruding from the rectangular housing (50). On the contrary, notches (45, 46) can be formed at the inner periphery of the magnetic and mechanical continuity part (41) to meet the mechanical attachment requirements of the stator (20).

[0082] Figure 2 Also shown are slots for accommodating coils that expand in the direction of the rotor. The expansion angle selected between the edge of the tooth and the other side of the slot enables the adjustment of the inductance of the coil.

[0083] Of course, the angle between the axes (A1, A2) of the wound teeth (21, 22) has been modified in the same way as in the previous version. In this case, in order to simulate the optimal three-phase control, the angle must be equal to 168°.

[0084] Third variant embodiment

[0085] Figure 3 Shows a third variant of the present invention. It differs from the Figure 1 embodiment shown in that the most open corner sector (α2) does not have a magnetic and mechanical continuity part (42), but has two extensions (42a, 42b) of the peripheral band (40), which are separated by a gap (49) to ensure the return of the magnetic flux between the wound teeth (21, 22) and the rotor (10), and each of these extensions is terminated by an unwound tooth (27, 28).

[0086] This configuration is particularly useful when it is necessary to reduce the stator width. In the Figure 1 example shown, the width of the rectangular housing (50) surrounding the stator in the corner sector (α2) is related to the cross-section of the magnetic and mechanical continuity part (42). This cross-section must be at least equal to half of the width w of the teeth (21, 22) and must be spaced from the rotor by a distance of the air gap e. As shown in Figure 3 ​As shown, the elimination of the magnetic and mechanical continuity removes this constraint. The rectangular housing (50) surrounding the rotor is then constrained by the angular width and positioning of the unwound teeth (27, 28), which are both directly related to the no-current torque of the electromechanical device. Thus, this structure makes a trade-off between optimizing the no-current torque and its overall size. However, it should be noted that a similar trade-off can be achieved in the Figure 1 version shown. To this end, the overall size of the magnetic and mechanical continuity (42) can also be reduced to the detriment of the magnetic properties.

[0087] An interesting aspect of this configuration is that the undercut (49) of the peripheral band (40) located in the most open-angle sector (α2) can be used to accommodate a magnetic sensor to obtain, for example, information about the position or rhythm of the rotor (10).

[0088] Fourth Variant Embodiment

[0089] Figure 4 shows a fourth variant of the present invention. It differs from the Figure 3 previous embodiment shown in that the peripheral band (40) is closed between the teeth (27, 28) by a magnetic and mechanical continuity (42), and the magnetic and mechanical continuity (41) of the most closed-angle sector (α1) is also provided with two teeth (25, 26).

[0090] This configuration is advantageous when it comes to fine-tuning the no-current torque, as it leaves several degrees of freedom for the width of the unwound teeth (25, 26, 27, 28) and their positioning relative to the adjacent wound teeth (21, 22). To achieve this optimization, the symmetry of the stator (20) with respect to the plane P is maintained, but an angular deviation is formed between the central axes of the teeth (25, 26) in the most closed-angle sector (α1) and the central axes of the adjacent wound teeth, which is different from the angular deviation Figure 4 formed between the central axes of the teeth (27, 28) in the most open-angle sector (α2) and the central axes of the adjacent wound teeth. In the example shown in the angular deviation is 45°, while the angular deviation

[0091] Figures 1 to 4 is 55°. The optimal angular distance depends directly on the polarity of the rotor, but as a general rule, one of these angles should be less than or equal to 45°, while the other angle should be greater than 45°.

[0091] Figures 1 to 4 The variants shown inFigure 3 As shown, a structure having only one magnetic continuous part but two teeth. Alternatively, a 6-pole magnetic structure (11, 12) not shown can be easily selected, and then an angle of 150° located between the axes (A1, A2) of the winding teeth (21, 22) will be adopted.

[0092] Figures 1 to 4 Specific examples of the variant for the above application shown in will generally have a rotor diameter D of 11.85 mm, a length L1 of 36.5 mm, and a width L2 of 16.15 mm for the version with 8 magnetization poles (11, 12), and a width L2 of 15.35 mm for the version with 10 magnetization poles (11, 12). For the 8-pole version, thus the L2 / L1 ratio = 0.44 and the D / L2 ratio = 0.73 are obtained, and for the 10-pole version, the L2 / L1 ratio = 0.42 and the D / L2 ratio = 0.77.

[0093] Mechatronic integration

[0094] The present invention also relates to a mechatronic component having one of the following variants:

[0095] 1. A motor integrated with an actuator with or without a speed reducer

[0096] 2. A motor integrated with an actuator with gear reduction

[0097] 3. A motor integrated into an actuator with linear transformation.

[0098] According to Figure 5 、 Figure 6 and Figure 7 shown in the example, the electric motor (1) according to the present invention is associated with a motion reduction gear train (120) and is integrally incorporated into a housing (100) to form a very compact actuator, which is designed to motorize, for example, an air-conditioning shutter. Figure 5 shows a front view with the upper cover (101) of the housing removed, Figure 6 shows a side sectional view of the actuator at the motor output end and parallel to the lamination plane of the stator laminations (20), and Figure 7shows a longitudinal cross - sectional view of only the housing along the dashed axis AA’, which makes it possible to understand the positioning of the stator (20) and the guidance of several moving parts of the gearbox. In this embodiment, compared to a conventional integrated motor actuator, the motor is positioned in the housing (100) in a transverse plane parallel to the side (102) of the housing (100), in which conventional integrated motor actuator, the motor is arranged such that the rotor axis (110) is perpendicular to the bottom of the housing and the output axis of the actuator. "Integrated motor actuator" is understood to mean an actuator in which the motor and the gearbox are not subsequent assembled integrated components, but a very compact actuator in which a single housing directly integrates the gearbox and the electric motor components without an intermediate housing.

[0099] The rotor shaft (110) is coupled to a worm (121) that drives a first gear element (123) (i.e., pinion / gear assembly) of a spur gear sub - assembly (122) of a motion reducer (120). The rotational axes of the respective gear elements (123, 124, 125) of the spur gear sub - assembly (122) are parallel and all perpendicular to the rotational axis of the rotor (10). The last gear element of the spur gear sub - assembly (110) is an output wheel (113) through which a polygonal coupling slot (126) passes to connect it to the member to be driven by the actuator. The printed circuit board (2) is located between the motor (1) and the side (102). The side flanges (61, 62) of the stator (20) abut along their long lengths against the longitudinal walls (103, 104) of the housing such that the motor and its electronics occupy the entire distal space of the housing (100), where the motion reducer (120) extends into the proximal space of the said housing (100). A connector (3) soldered to the printed circuit board (2) passes through an opening in the side (102). The ingenious coupling between the rotor (10) and the motion reducer (120) via the worm (121) makes the actuator irreversible and thereby prevents the accidental movement of the member to be driven. This is difficult to achieve with prior - art solutions when it is also desired to maintain a specific form factor of the actuator along the direction of its output axis. The result is a highly compact high - performance actuator that is 59 mm long, 42 mm wide, and only 20 mm thick in the direction of its output axis.

[0100] Figures 8 to 10An application of an electric machine according to the present invention for generating a fluid valve (200) is shown. This embodiment is similar to the known prior art of a valve actuator with a submerged rotor (10), where the electric motor (1) is positioned laterally above the valve body (201), and the rotor (10) fixed to the needle (210) is integrated in a sealed cartridge (202) provided with its guiding means which are directly screwed onto the valve body (201). Once the cartridge (202) has been assembled and all leak tests have been carried out in a controlled environment, the stator (20) integrated into the housing (220) can be fitted to the valve body (201). The rotor (10) has an internal cavity (240) provided with a tapping (241) that engages with the thread (225) of the axial projection (224) of the base of the cartridge (221). The needle (210) is attached to the axial end (245) of the rotor opposite the valve body (201) and extends through the internal cavity (240) of the rotor. The axial projection (224) of the base of the cartridge (221) is provided with a longitudinal hole (226) for guiding the rotor (10) in cooperation with the needle (210). The needle (210) passes through the longitudinal hole (228) into the valve body (201) so as to seal the fluid delivery valve duct (230) when it moves to the end of its stroke. The linear travel of the needle (210) is achieved by supplying power to the coils (31, 32) to rotate the rotor (10), thereby screwing the rotor onto the axial projection of the base of the cartridge, which causes a helical displacement movement of the rotor (10) and the needle (210) fixed thereto. The rotor (10) that moves linearly during its stroke is fitted with a magnetization ring (15) whose height is equal to the thickness of the stator stack (29) plus the axial displacement distance of the needle (210) in order to ensure the same magnetic properties over the entire opening stroke. Incorporating the present invention into a valve of this type greatly reduces the space required for motorization. In fact, as shown in Figure

[10] , when oriented in the direction of the valve duct (230), the very slender shape of the electric motor (1) advantageously allows the overall dimensions of the valve to be increased only in the direction of the axis of the needle (210), thereby forming a very compact assembly.

[0101] Fourth variant embodiment

[0102] Figure 11 ​shows a variant of the present invention, in which two motors (1a and 1b) are mechanically coupled by their stators (20a and 20b) cut from the same lamination stack. This embodiment is advantageous for highly compact applications where two closely spaced shafts need to be driven to rotate independently. Here, the distance between the two rotors (10a and 10b) is less than the length of the assembly. In this embodiment, the two stators are adjacent to each other at their most closed angular sectors to form mirror symmetry, but the present invention is not limited to this embodiment, and the stators (20a and 20b) can also be coupled, one on one side of the most open angular sector and the other on one side of the most closed angular sector, or both on one side of the most open angular sector. As a possible variant, a greater number of motors can be juxtaposed to drive a desired number of nearby shafts to rotate independently.

Claims

1. A two-phase brushless motor, the two-phase brushless motor being composed of a rotor (10) and a stator (20), the stator (20) being composed of a stack of cut ferromagnetic laminations having two teeth (21, 22), each tooth extending along a middle radial axis (A1, A2), the middle radial axes (A1, A2) being coplanar, the cross-section of the stator being inscribed in a rectangle having a length L1 and a width L2, each of the teeth (21, 22) being surrounded by coils (31, 32) powered respectively by one phase and another phase of the phases, the rotor (10) including three pairs, four pairs or five pairs of magnetic poles magnetized radially in alternating directions, the two-phase brushless motor being characterized in that the middle radial axes (A1, A2) form an angular sector (α1) extending within an angle between 145° and 180° therebetween, and the stator (20) has at least one mechanically and magnetically continuous part (41, 42) extending between the two wound teeth (21, 22).

2. The two-phase brushless motor according to claim 1, wherein, The middle radial axes (A1, A2) form an angle of 157.5° with each other, and the rotor (10) has 4 pairs of poles.

3. The two-phase brushless motor according to claim 1, wherein, The middle radial axes (A1, A2) form an angle of 162° with each other, and the rotor (10) has 5 pairs of poles.

4. The two-phase brushless motor according to claim 1, wherein The middle radial axes (A1, A2) form an angle with each other in such a way that the two coils are electrically phase-shifted by 120°.

5. The two-phase brushless motor according to claim 1, characterized in that, The yoke has a second mechanically and magnetically continuous part, and one or the other of the mechanically and magnetically continuous parts forms at least one continuous unwound tooth, and the first mechanically and magnetically continuous part and the second mechanically and magnetically continuous part (41, 42) extend between the two wound teeth (21, 22) on either side of the rotor (10), and the first mechanically and magnetically continuous part and the second mechanically and magnetically continuous part (41, 42) have different angular widths.

6. The two-phase brushless motor according to claim 5, wherein, The second mechanically and magnetically continuous part (42) of the mechanically and magnetically continuous parts forms a single unwound continuous tooth.

7. The two-phase brushless motor according to claim 4 or 5, characterized in that, The middle radial axis of each of the one or more unwound continuous teeth is equidistant from the middle radial axes (A1, A2).

8. The two-phase brushless motor according to claim 4 or 5, characterized in that, The angular width of one or more continuous unwound teeth is between 60° and 130°.

9. The two-phase brushless motor according to claim 1, characterized in that, The mechanically and magnetically continuous parts (41, 42) form two unwound teeth (25, 26; 27, 28), and the middle radial axis of each of the unwound teeth forms an angle greater than 45° with the middle radial axis (A1, A2) of the nearest wound tooth.

10. The two-phase brushless motor according to claim 1, wherein, The mechanically and magnetically continuous part forming two unwound teeth is located in the smallest extended angular sector separating the middle radial axes (A1, A2).

11. The two-phase brushless motor according to claim 1, wherein, The yoke has a discontinuity extending between the two wound teeth on the side opposite to the mechanically and magnetically continuous part.

12. The two-phase brushless motor according to claim 1, wherein, The ratio of the rotor diameter D to the rotor length L1 is greater than 50%.

13. The two-phase brushless motor according to claim 1, wherein The ratio of the width L2 of the outer housing of the stator to the length L1 is between 0.4 and 0.

6.

14. The two-phase brushless motor according to claim 1, wherein The ratio between the width L2 and the length L1 of the outer housing of the stator is between 0.4 and 0.

5.

15. The two-phase brushless motor according to claim 1, wherein, The rotor is coupled to a worm, which constitutes the first module of the motion conversion.

16. The two-phase brushless motor according to claim 15, wherein, The motion conversion is of the rotational-linear type that controls the linear displacement of the output member.

17. The two-phase brushless motor according to claim 16, wherein, The member is a needle.

18. The two-phase brushless motor according to claim 13, characterized in that, The motion transformation is a linear displacement collinear with the axis of the rotor.

19. The two-phase brushless motor according to claim 13, characterized in that, The motion conversion is of the rotational-rotational type that controls the rotation of the output shaft.

20. The two-phase brushless motor according to claim 13, wherein, The output shaft is oriented in a direction perpendicular to the direction of the axis of the rotor.

21. An electromechanical system, the electromechanical system comprising a brushless motor and a generally parallelepiped housing, characterized in that, The electric machine is the electric machine according to claim 1, and the axis of the rotor is oriented along the long length of the parallelepiped housing defining the outer casing.

22. The electromechanical system according to claim 21, wherein, The electromechanical system includes a printed circuit board arranged between the electric machine and the outer casing, and the face of the printed circuit board of the electric machine has a connector passing through a cutout provided in the lateral face of the outer casing.

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