Small two-phase motor

Abstract

The present invention relates to a two-phase brushless electric motor comprising a rotor (10) and a stator (20), the stator (20) being made of a stack of cut ferromagnetic laminations, each having two teeth (21, 22) extending along a central radial axis (A1, A2), the central 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, and each of the teeth (21, 22) being connected by a coil (31, 32). the rotor (10) is surrounded by three, four or five magnetic pole pairs that are radially magnetized in alternating directions, the central radial axes (A1, A2) form an angular sector (α1) therebetween that extends over an angle of 145° to 180°, and the stator (20) has at least one mechanical and magnetic continuity (41, 42) extending between two winding teeth (21, 22).

Description

[Technical Field]

[0001] The present invention relates to two-phase brushless electric motors, particularly motors integrated into mechatronic systems, and in particular to automotive peripherals with very strict space constraints, such as the actuation of expansion valves or air flow diverter flaps in air conditioning modules. [Background technology]

[0002] (prior art) An example of such a motor is described in the applicant's French Patent No. 2742940, which proposes a two-phase motor consisting of a stator section excited by two electric coils and a magnetized rotor with N pairs of radially magnetized poles in alternating directions, where N is equal to 3 or 5. The stator section features at least two W-circuits, each with an electric coil surrounding a central leg. The W-circuits are arranged so that when one central leg faces a magnetic transition, the other central leg faces a magnetic pole. The pole pieces of the legs of the W-circuits are angularly spaced apart by π / 4, and the pole pieces of the central legs of two W-circuits belonging to different phases are angularly spaced apart by an angle substantially equal to π / 2±k.π / N, where N is the number of pole pairs, which can be either 3 or 5, and k is equal to 0, 1, or 2.

[0003] Other similar motors are known, for example, from EP 1713166, which describes a drive device comprising a stator, a rotor with a core made of soft magnetic material and a shaft attached to the core, and a magnet having a cylindrical shape and magnetized with different poles alternating circumferentially. A first coil is wound around the first external pole piece through the coil at an axial position between the magnet and the base. A second coil is wound around the second external pole piece through the coil at an axial position between the magnet and the base.

[0004] The needle valve described in European Patent No. 2484948 comprises a housing in which a first port communicating with one end of a cylindrical communicating hole and a second port communicating with the other end of the communicating hole are formed, and a needle valve stem with a tapered portion that is mounted within the communicating hole so as to be freely movable in the axial direction, the outer diameter of which changes from one end side to the other end side of the communicating hole, and the gap between the needle valve stem and the valve seat surface of the communicating hole changes depending on the axial position.

[0005] US Patent No. 2017338113 describes a motor comprising a stator and a rotor rotatably disposed within the stator, the rotor comprising a rotatable shaft and a gearbox driven by the motor, the gearbox comprising a housing to which the motor is mounted, a gear mounted to the housing and driven by the rotatable shaft of the motor, and two first bearings mounted within the housing on the same side of the stator to support the rotatable shaft and allow the stator to pivot relative to the housing. Summary of the Invention

[0006] (Drawbacks of the prior art) It has become clear that the various shapes proposed in the prior art result in solutions that, for a given power, are penalized by a relatively high residual no-current torque C0 and a footprint in one of the directions belonging to the plane perpendicular to the axis of rotation, which can be improved and limited. In particular, prior art solutions featuring a "W"-shaped magnetic circuit are unsatisfactory in terms of no-current torque when only the winding teeth form an angle of more than 120° and the magnetic circuits are magnetically connected, resulting in interactions between these magnetic circuits that negatively affect the no-current torque.

[0007] Some prior art solutions also have the disadvantage of requiring complex stator geometries that are not compatible with conventional techniques for stacking thin ferromagnetic laminations, such as expensive 3D lamination formation or multi-component assembly.

[0008] DISCLOSURE OF THE INVENTION The present invention aims to address these drawbacks. To this end, in its most general scope, the invention relates to a two-phase brushless electric motor having the features set forth in claim 1.

[0009] It comprises a rotor and a stator, the stator consisting of a stack of cut ferromagnetic laminations, each having two teeth extending along a central radial axis, the central radial axis 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 being surrounded by a coil, the rotor having three, four or five magnetic pole pairs that are radially magnetized in alternating directions, the central radial axis forming an angular sector between them extending over an angle of more than 145° and less than 180°, and the stator having at least one mechanical and magnetic continuum extending between two wound teeth.

[0010] The object of the present invention may also have one or compatible combinations of the following features:

[0011] In particular, the central radial axes form an angle of 157.5° with one another and the rotor has four pairs of poles.

[0012] Alternatively, the central radial axes form an angle of 162° with each other and the rotor has five pairs of poles.

[0013] In another alternative, the central radial axes are angled relative to one another such that the two coils are electrically phase shifted by 120°.

[0014] In a first variant, the yoke has a second mechanical and magnetic continuum, one or the other of which forms at least one continuous unwound tooth, the first and second mechanical and magnetic continuum extending on either side of the rotor between two wound teeth, and the first and second mechanical and magnetic continuum having different angular widths.

[0015] In particular, in this first variant, the second of said mechanical and magnetic series forms a single continuous non-wound tooth.

[0016] According to this variant, the central radial axis of each of the successive non-wound teeth can be located equidistant from the central radial axis.

[0017] Also, according to this modification, the angular width of the continuous non-wound teeth can be 60° to 130°.

[0018] In another variation, the mechanical and magnetic continuum forms two unwound teeth, each of which has a central radial axis that forms an angle of greater than 45° with the central radial axis of the nearest wound tooth.

[0019] In another variant, the mechanical and magnetic continuation forming the two unwound teeth is located in the smallest extending angular sector separating the central radial axes.

[0020] Alternatively, the yoke has a discontinuity extending between two winding teeth opposite the mechanical and magnetic continuity.

[0021] In another variant, the ratio between the diameter D and the length L1 of the rotor is greater than 50%.

[0022] In one variation, the ratio of the width L2 to the length L1 of the stator outer casing is 0.4 to 0.6.

[0023] In particular, the ratio between the width L2 and the length L1 of the stator outer casing is 0.4 to 0.5.

[0024] In one variant, the rotor is coupled to a worm screw that forms the first module of the motion conversion system.

[0025] In particular, the motion conversion is of the rotary-linear type that controls the linear displacement of the output member.

[0026] More precisely, the member in question is a needle.

[0027] Alternatively, the motion transformation is a linear displacement collinear with the rotor axis.

[0028] In another alternative, the motion transformation is of the rotary-rotary type, controlling the rotation of the output shaft.

[0029] In one variant, the output shaft is oriented perpendicular to the direction of the rotor axis.

[0030] The invention also relates to a mechatronic system comprising a brushless electric motor and a substantially parallelepiped housing, characterized in that the motor is according to one of the aforementioned variants and that the rotor axis is oriented along the longitudinal direction of the parallelepiped casing that defines the housing.

[0031] In particular, the mechatronic system includes a printed circuit board disposed between the motor and the housing, the face of the motor printed circuit board having a connector passing through a notch in a transverse face of the housing. [Brief explanation of the drawings]

[0032] The invention will be better understood on reading the following description of non-limiting exemplary embodiments illustrated by the accompanying drawings, in which:

[0033] [Figure 1] FIG. 1 is a front view of a first example of a motor according to the present invention having four pairs of magnetized poles. [Figure 2] FIG. 10 is a front view of a second example of a motor according to the present invention having five pairs of magnetized poles. [Figure 3] FIG. 10 is a front view of a third example of a motor according to the present invention having magnetic and mechanical discontinuities. [Figure 4] FIG. 10 is a front view of a fourth example of a motor according to the present invention. [Figure 5]1 is a front view of an example of a shutter movement actuator incorporating a motor according to the present invention, with the actuator housing having its cover removed. [Figure 6] 1 shows a cross section perpendicular to the rotor axis of the actuator shown in the previous figure. [Figure 7] 6 shows a cross-sectional view AA' of the actuator shown in FIG. [Figure 8] FIG. 1 shows a front view of an example of the integration of a motor according to the present invention in an expansion valve actuator. [Figure 9] FIG. 1 shows a cross-sectional view of the actuator shown in the previous figure. [Figure 10] 9 shows a cross-sectional view perpendicular to the rotor axis of the valve actuator shown in FIG. 8 with the housing cover removed. [Figure 11] 1 shows a perspective view of a variant having two coupled stators. DETAILED DESCRIPTION OF THE INVENTION

[0034] (General principle of the present invention) It is an object of the present invention to provide a two-phase electric motor that is easy to manufacture, has high performance, and is compact. In particular, the present invention relates to a motor having a form factor with the rotor's axis of rotation perpendicular that is optimized for incorporation into a compact housing having a rotor axis positioning perpendicular to the cross section of the housing.

[0035] In certain mechatronic applications (such as grille shutter actuators and fluid valves), the form factor required for optimal integration of the motor into the actuator housing means that in the motor's cross section (orthogonal to its axis of rotation), one dimension along one axis is much smaller than the other, resulting in a motor with a fairly elongated, substantially tubular casing, but differing from prior art long form motors in that the rotor's axis of rotation is orthogonal to the casing's longitudinal extent and located close to the center along this longitudinal extent. Hereinafter, motor width refers to the smallest motor dimension in cross section, length refers to the largest motor dimension in cross section, and thickness refers to the dimension orthogonal to the cross section.

[0036] In a particular application for an automotive climate control flap control, the stator plane perpendicular to the axis of rotation is inscribed in the smallest cross section of the actuator.

[0037] However, these dimensional constraints must maintain motor performance in terms of torque and electromechanical efficiency, and by reducing the residual torque in the absence of current observed in prior art solutions.

[0038] To this end, the motor according to the invention comprises a stator having only two winding teeth, the first of which carries a first coil powered by a first phase and the second of which carries a second coil powered by the opposite phase of a two-phase power supply. The angle formed between the central radial axes of the two teeth is 155° to 150° if the rotor has four pairs of poles, 160° to 165° if the rotor has five pairs of poles, or an angle such that the two coils are electrically out of phase by 120°.

[0039] (Geometrical Features of the Motor According to the Present Invention) The two-phase electric motor (1) according to the present invention comprises a rotor (10) and a stator (20) on which two coils (31, 32) are mounted, each connected to a different electrical phase that supplies power to the two-phase motor. The stator (20) is formed by a stack of ferromagnetic thin laminations, all of which have identical cutouts and are symmetrical about a transverse median plane P. The laminations comprise a closed peripheral belt (40) inscribed in a rectangular casing (50) of length L1 and width L2, as viewed in the lamination plane, and which has cutouts for forming two teeth (21, 22) intended to carry the two electric coils (31, 32). These two teeth (21, 22) are oriented radially relative to the rotor (10) and extend along two coplanar axes (A1, A2) angularly separated by an angle of more 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 a peripheral belt so as to ensure at least mechanical and magnetic continuity (41, 42) between the teeth (21, 22). The angular separation of the wound teeth (21, 22) at a very wide angle minimizes the radial footprint of the stator in the angular sectors (α1, α2), in which the laminations are cut to the strict minimum necessary to ensure good magnetic connection with the rotor and to ensure the mechanical strength of the stator assembly.

[0040] The lamination plane of a laminate is the plane perpendicular to the thickness of the laminate, i.e., the smallest dimension of the laminate before cutting. The laminates are stacked perpendicular to this plane to form a laminate pack.

[0041] The rotor (10) has a diameter D and is inscribed in the rectangular casing (50) of the stator laminations, with a rotor diameter to stator width ratio greater than 50%. The rotor has N magnetized poles (11, 12), where N is 6, 8, or 10, distributed in alternating orientations around its circumference to form north poles (11) and south poles (12). These poles are preferentially produced in a monolithic magnet ring molded on a cylindrical core, but may alternatively be obtained by any other technique known to those skilled in the art, such as, but not limited to, pressing a ring, gluing magnetized tiles, or even magnetizing injection magnets that make up the monolithic rotor.

[0042] The length of the winding teeth (21, 22) is carefully selected to match the structure of the electric coils (32, 32) on the coil body, which is then inserted onto the teeth (21, 22) of the laminated core through the internal space opened up to accommodate the rotor (10). Therefore, the length of the winding teeth (21, 22) must be smaller than the rotor diameter D plus twice the magnetic air gap e, which corresponds to the difference between the tooth flanks (21, 22) and the outer periphery of the rotor.

[0043] (First modified embodiment) FIG. 1 shows a first variant of the present invention, with an eight-pole magnetic rotor (11, 12). To optimize magnetic performance, the axes (A1, A2) of the winding teeth (21, 22) are angularly separated by 157.5°, the widest angle that allows for perfect magnetic orthogonality between the winding teeth (21, 22). Thus, when one of two teeth (21, 22) faces the transition between two rotor poles (11, 12), the other faces the center of the other pole. To ensure good magnetic flux feedback, the winding teeth (21, 22) are connected by mechanical and magnetic continuities (41, 42) in each angular sector (α1, α2). The cross section w of the angular sector, i.e., the thickness of the laminations in the lamination plane, must be sufficient to ensure the passage of magnetic flux without saturation and is therefore equal to half the width of the winding teeth (21, 22). This constraint defines the maximum overall dimensions of the stator and hence the length L1 and width L2 of the rectangular casing (50).

[0044] These parameters can be written as a function of the motor sizing variables as follows:

[0045]

number

number

[0046] where θ is half 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 tooth bottom. These last two values ​​are written as follows:

[0047]

number

[0048] B2=3×w+2×l s

[0049] In the formula, ls is the width of the winding slot, 1 is the length of the tooth, and there are the following constraints on coil insertion:

[0050] 1≦D+2×e

[0051] The width of the teeth (21, 22), i.e., 2*w, preferably gives the following relationship with respect to the opening angle P of the front faces of the teeth (21, 22):

[0052]

number

[0053] Finally, the width of the slot, l s is set by the edge of the face of the nearest unwound tooth, and the angle formed between the center of the tooth and this edge is called γ, giving:

[0054]

number

[0055] Preferably, the angles β and γ are: 14°≦β≦30°, and 35°≦γ≦65°, It is selected to comply with the following ratio:

number

number

[0056] Compared to the prior art in asymmetric two-phase motors, which often prefer a closing angle equal to 90°, this configuration has the advantage of better balancing the magnetic forces and therefore limiting the vibrations associated with force fluctuations between the rotor and the stator.

[0057] To minimize the idle torque and vibration, the mechanical and magnetic continuations (41, 42) each feature a protrusion that extends toward the rotor to form a widely flared, unwound tooth (23, 24), which spans most of the angular sector (α1, α2), leaving only the space necessary for a slot to accommodate the electrical coil (31, 32) supported by the tooth (21, 22). Because the angular sectors (α1, α2) have different widths, the faces of the unwound tooth (23, 24) span different angular ranges, but greater than 60°, while the wound tooth (21, 22) instead has a tooth flank that spans an angle of 20°. The resulting two-phase motor has a substantially smooth air gap, with notches only around the teeth (21, 22) to accommodate the coil (31, 32).

[0058] It should be noted that this wide tooth configuration makes it possible to cut out the outer periphery of the magnetic and mechanical continuum (240) located in the most closed angular sector (α1). The cutouts (43, 44) thus formed allow the stator (20) to be fixed without protruding beyond the rectangular casing (50), while leaving a sufficient cross-section for the passage of magnetic flux through the magnetic and mechanical continuum (41). The most open angular sector (α2) provides more space for ensuring mechanical strength without protruding beyond the rectangular casing (50), so that the second magnetic and mechanical continuum (42) can have a larger cross-section for providing holes (47, 48) for ensuring very accurate positioning of the stator and its support, while still providing a sufficient cross-section for the passage of magnetic flux.

[0059] Naturally, the 157.5° angle between the axes (A1, A2) of the winding teeth (21, 22) is optimal for two-phase control of two coils. However, those skilled in the art can imagine modifying this angle to achieve different objectives. For example, the angle can be slightly altered to improve current-free torque while intentionally reducing magnetic performance in terms of torque density. An alternative motivation is to achieve three-phase drive using only two coils. The two coils can, in fact, be powered together to emulate the missing coil of a three-phase drive. In this case, the winding teeth (21, 22) must be positioned to achieve a 120° electrical angle between the coils. This means that the voltage induced by the rotor rotation generates signals at the terminals of the two windings that are 120° out of phase. In this case, to achieve optimal steering compatible with the present invention, the angle between the axes (A1, A2) of the winding teeth (21, 22) is 165°. Naturally, we misuse the term three-phase control, since the electrical vector corresponds to this type of control, but remains within the framework of a two-phase motor, where only two windings are supplied. Second Variant Embodiment

[0060] Figure 2 shows a second variant according to the invention. It differs from the previous design in that the rotor has ten magnetic poles (11, 12). To keep the teeth (21, 22) wound in quadrature, the angle between the axes (A1, A2) is increased to 162°. This configuration results in an even flatter motor than the version shown in Figure 1, which has eight magnetic poles (11, 12).

[0061] The direct consequence is that the outer periphery 41 of the magnetic and mechanical continuum, located in the most closed angular sector (α1), is closer to the rotor. The cross section of the magnetic and mechanical continuum (41) is therefore smaller, which no longer allows for cutouts on its outer periphery, as shown in Figure 1, without affecting the passage of magnetic flux or causing the cylindrical mounting means to protrude from the rectangular casing (50). Conversely, cutouts (45, 46) can be formed on the inner periphery of the magnetic and mechanical continuum (41) to meet the mechanical mounting requirements of the stator (20).

[0062] Figure 2 also shows slots for accommodating coils that flare out in the direction of the rotor. The flare angle chosen between the edge of the tooth and the other side of the slot makes it possible to adjust the inductance of the coil.

[0063] Naturally, the angle between the axes (A1, A2) of the winding teeth (21, 22) has been changed as in the previous version: in this case, the angle must be equal to 168° to emulate optimal three-phase control.

[0064] (Third modified embodiment) Figure 3 shows a third variant of the invention, which differs from the embodiment shown in Figure 1 in that the most open angular sector (α2) is devoid of magnetic and mechanical continuity (42), but has two extensions (42a, 42b) of the peripheral belt (40) separated by a clearance (49) to ensure magnetic flux return between the wound teeth (21, 22) and the rotor (10), each of these extensions being terminated by a non-wound tooth (27, 28).

[0065] This configuration is particularly useful when the stator width needs to be reduced. In the example shown in FIG. 1, the width of the rectangular casing 50 surrounding the stator is related to the cross section of the magnetic and mechanical continuum 42 in the angular sector (α2). This section must be at least equal to half the width w of the teeth (21, 22) and must be spaced from the rotor by the distance of the air gap e. The elimination of the magnetic and mechanical continuum, shown in FIG. 3, removes this constraint. The rectangular casing 50 surrounding the rotor is then constrained by the angular width and the positioning of the unwound teeth (27, 28), both of which are directly related to the no-current torque of the electric machine. Therefore, this structure is subject to a compromise between optimizing the no-current torque and its overall size. However, it should be noted that a similar compromise can be achieved in the version shown in FIG. 1, thereby reducing the overall size of the magnetic and mechanical continuum 42 to the detriment of magnetic performance.

[0066] This configuration is also interesting in that the undercut (49) in the peripheral belt (40) located in the most open angular sector (α2) can be used to accommodate, for example, a magnetic sensing probe for obtaining position or cadence information of the rotor (10).

[0067] (Fourth modified embodiment) Figure 4 shows a fourth variant of the invention, which differs from the previous embodiment shown in Figure 3 in that the peripheral belt (40) is closed between the teeth (27, 28) by a magnetic and mechanical continuation (42), and that the magnetic and mechanical continuation (41) of the most closed angular sector (α1) also comprises two teeth (25, 26).

[0068] This configuration is advantageous when it comes to fine-tuning the non-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 the angular deviation (φ1) formed between the central axes of the teeth (25, 26) in the most closed angular sector (α1) and the adjacent wound tooth is different from the angular deviation (φ2) formed between the central axes of the teeth (27, 28) in the most open angular sector (α2) and the adjacent wound tooth. In the example shown in FIG. 4, the angular deviation (φ1) is 45° and the angular deviation (φ2) is 55°. The optimal angular distance (φ1, φ2) depends directly on the rotor polarity, but generally, one of these angles should be less than or equal to 45°, and the other should be greater than 45°.

[0069] The variants shown in Figures 1 to 4 are in no way limiting with respect to the present invention, and those skilled in the art can judiciously combine one or more of the aforementioned features. For example, the polarity of the rotor can be changed and the stator structure can be adapted to obtain the above-mentioned advantages, such as a structure with only one magnetic continuum but two teeth, as shown in Figure 3. Alternatively, a six-pole magnetic structure (11, 12) not shown can be easily selected, which would then adopt an angle of 150° between the axes (A1, A2) of the winding teeth (21, 22).

[0070] 1-4 for the above-mentioned applications typically 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 eight magnetized poles (11, 12), and 15.35 mm for the version with ten magnetized poles (11, 12). Thus, for the eight-pole version, we obtain an L2 / L1 ratio of 0.44 and a D / L2 ratio of 0.73, and for the ten-pole version, we obtain an L2 / L1 ratio of 0.42 and a D / L2 ratio of 0.77.

[0071] (Mechatronics Integration) The invention also relates to a mechatronic assembly having one of the following variants: 1. Actuator integrated motor with or without reducer 2. Motor with integrated actuator and gear reducer 3. Motors integrated into actuators with linear translation.

[0072] According to the example shown in Figures 5, 6, and 7, an electric motor (1) according to the present invention is associated with a motion reduction gear train (120) and is entirely integrated into a housing (100) to form a very compact actuator designed, for example, to motorize an air conditioner shutter. Figure 5 shows a front view with the housing's top cover (101) removed, Figure 6 shows a side cross-sectional view of the actuator parallel to the lamination plane of the stator laminations (20) at the electric motor output, and Figure 7 shows a longitudinal cross-sectional view of the housing only along dashed axis AA', which makes it possible to understand the positioning of the stator (20) and the guidance of some of the moving parts of the gearbox. In this embodiment, the motor is positioned within the housing (100) in a transverse plane parallel to the side surface (102) of the housing (100), in contrast to conventional integrated motor-actuators in which the motor is positioned so that the rotor axis (110) is perpendicular to the bottom of the housing and the output axis of the actuator. An "integrated motor actuator" is understood to mean a very compact actuator in which the motor and gearbox are not one-piece components that are subsequently assembled, but rather a single housing directly integrates the gearbox and electric motor components without an intermediate housing.

[0073] The rotor shaft (110) is coupled to a worm screw (121) that drives a first gear element (123) of a spur gear subassembly (122) of the motion reducer (120), i.e., a pinion / gearwheel assembly; the rotational axes of the various gear elements (123, 124, 125) of the spur gear subassembly (122) are parallel and all perpendicular to the axis of rotation of the rotor (10). The final gear element of the spur gear subassembly (110) is the output wheel (113), and a polygonal coupling slot (126) passes through the output wheel (113) to connect it to a member driven by the actuator. A printed circuit board (2) is disposed between the motor (1) and the side surface (102). The lateral flanks (61, 62) of the stator (20) are adjacent along their length to the longitudinal walls (103, 104) of the housing, so that the motor and its electronics occupy the entire distal volume of the housing (100), while the motion reducer (120) extends into the proximal volume of the housing (100). A connector (3) soldered to the printed circuit board (2) passes through an opening in the side wall (102). The clever coupling between the rotor (10) and the motion reducer (120) via a worm screw (121) makes the actuator irreversible, thus preventing unintended movement of the driven member. This is difficult to achieve with prior art solutions when the size of the actuator also requires maintaining a specific form factor along its output axis. The result is a highly compact, high-performance actuator measuring 59 mm in length, 42 mm in width, and only 20 mm thick in the output axis direction.

[0074] Figures 8-10 illustrate the application of a motor according to the present invention to the manufacture of a fluid valve (200). This embodiment is similar to known prior art valve actuators with submerged rotors (10), in that the electric motor (1) is positioned laterally above the valve body (201), and the rotor (10), fixed to the needle (210), is incorporated into a sealed cartridge (202) with guide means threaded directly into the valve body (201). The stator (20), integrated into the housing (220), can be fitted to the valve body (201) once the cartridge (202) is assembled and all leak testing is performed in a controlled environment. The rotor (10) has an internal cavity (240) with a tapping (241) that engages with the threads (225) of the axial protrusion (224) at 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 rotor's internal cavity 240. An axial projection 224 at the base of the cartridge 221 has a longitudinal bore 226 for guiding the rotor 10 in cooperation with the needle 210. The needle 210 enters the valve body 201 through the longitudinal bore 228 and seals the fluid-carrying valve duct 230 as the needle moves to the end of its stroke. Linear movement of the needle 210 is achieved by rotating the rotor 10 via power supply to the coils 31, 32, thus threading the rotor onto the axial projection at the base of the cartridge, resulting in a helical displacement movement of the rotor 10 and the needle 210 fixed thereto. The rotor (10), which moves linearly during the stroke, is fitted with a magnetizing ring (15) whose height is equal to the thickness of the stator lamination pack (29) plus the axial displacement distance of the needle (210), thereby ensuring the same magnetic performance throughout the entire opening stroke. By incorporating the present invention into this type of valve, the space required for motorization is significantly reduced. Indeed, as shown in Figure 10, the very slender shape of the electric motor (1) advantageously allows, when oriented towards the valve duct (230), to increase the overall dimensions of the valve only in the direction of the needle axis (210), thus forming a very compact assembly.

[0075] (Fourth modified embodiment) FIG. 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 stack. This embodiment is advantageous for very compact applications requiring independent rotational driving of two closely spaced shafts. Here, the two rotors (10a and 10b) are separated by a distance shorter than the length of the assembly. In this embodiment, the two stators are adjacent to each other at their most closed angular sectors, forming mirror symmetry. However, the present invention is not limited to this embodiment; the stators (20a and 20b) can also be coupled so that one is on the side of the most open angular sector and the other is on the side of the most closed angular sector, or both are on the side of the most open angular sector. As a possible variant, more motors can be arranged side by side to independently drive the desired number of adjacent shafts.

Claims

1. A two-phase brushless electric motor consisting of a rotor (10) and a stator (20), each of which has a central radial axis (A １ , A ２ ) and the central radial axis (A １ , A ２ ) are on the same plane, and the cross section of the stator has a length L １ and width L ２ and each of the teeth (21, 22) is surrounded by a coil (31, 32) which is energized by one of the phases and the other of the phases, respectively, and the rotor (10) has three, four or five magnetic pole pairs which are radially magnetized in alternating directions, and the central radial axis (A １ , A ２ ) are spaced between them by an angular sector (α １ ) and the stator (20) has at least one mechanical and magnetic continuity (41, 42) extending between the two winding teeth (21, 22).

2. The central radial axis (A １ , A ２ 2. A two-phase brushless electric motor according to claim 1, characterized in that the rotor (10) has four pairs of poles, the rotors (10) forming an angle of 157.5° with respect to each other.

3. The central radial axis (A １ , A ２ 2. A two-phase brushless electric motor according to claim 1, characterized in that the rotor (10) has five pairs of poles, the rotors (10) forming an angle of 162° with respect to each other.

4. The central radial axis (A １ , A ２ 2. The two-phase brushless electric motor of claim 1, wherein the first and second coils are angled relative to each other such that the two coils are electrically phase shifted by 120 degrees.

5. 2. The two-phase brushless electric motor of claim 1, wherein the yoke has a second mechanical and magnetic continuity, one or the other of the mechanical and magnetic continuity forms at least one continuous unwound tooth, the first and second mechanical and magnetic continuity (41, 42) extending on both sides of the rotor (10) between the two wound teeth (21, 22), and the first and second mechanical and magnetic continuity (41, 42) having different angular widths.

6. 6. A two-phase brushless electric motor according to claim 1, wherein the second one of the mechanical and magnetic continuities (42) forms a single unwound continuous tooth.

7. The central radial axis of each of the non-wound consecutive teeth (A １ , A ２ 6. A two-phase brushless electric motor according to claim 4, wherein the first and second poles are equidistant from each other.

8. 6. A two-phase brushless electric motor according to claim 4 or 5, characterized in that the angular width of the consecutive unwound tooth(s) is between 60° and 130°.

9. The mechanical and magnetic continuation (41, 42) forms two non-wound teeth (25, 26; 27, 28), the central radial axis of each of the non-wound teeth being equal to the central radial axis (A) of the nearest wound tooth. １ , A ２ 2. The two-phase brushless electric motor of claim 1, wherein the first and second poles form an angle of greater than 45° with the first and second poles.

10. The mechanical and magnetic continuity forming the two unwound teeth is aligned with the central radial axis (A １ , A ２ 2. A two-phase brushless electric motor according to claim 1, characterized in that the rotors are located in the smallest extending angular sector separating the rotors.

11. 2. The two-phase brushless electric motor of claim 1, wherein the yoke has a discontinuity extending between the two winding teeth on a side opposite the mechanical and magnetic continuity.

12. Rotor diameter D and rotor length L １ 2. The two-phase brushless electric motor of claim 1, wherein the ratio of

13. The length L of the stator outer casing １ Width L ２ 2. The two-phase brushless electric motor of claim 1, wherein the ratio is between 0.4 and 0.

6.

14. The width L of the stator outer casing ２ and length L １ 2. The two-phase brushless electric motor of claim 1, wherein the ratio of .times. ...

15. 2. A two-phase brushless electric motor as claimed in claim 1, characterized in that said rotor is coupled to a worm screw which constitutes said first module of motion transformation.

16. 16. A two-phase brushless electric motor according to any one of claims 1 to 15, characterized in that the motion conversion is of the rotary-linear type, controlling the linear displacement of an output member.

17. 17. A two-phase brushless electric motor according to any one of claims 1 to 16, wherein the members are needles.

18. 14. The two-phase brushless electric motor of claim 13, wherein the motion transformation is a linear displacement collinear with the rotor axis.

19. 14. The two-phase brushless electric motor of claim 13, wherein the motion conversion is of rotary-to-rotary type, controlling the rotation of the output shaft.

20. 14. The two-phase brushless electric motor of claim 13, wherein the output shaft is oriented perpendicular to the axis of the rotor.

21. 10. A mechatronic system comprising a brushless electric motor and a substantially parallelepiped housing, the motor being a two-phase brushless electric motor as defined in claim 1, the rotor axis being oriented along a longitudinal direction of a parallelepiped casing defining the housing.

22. 22. The mechatronic system of claim 21, including a printed circuit board disposed between the motor and the housing, a face of the motor printed circuit board having a connector passing through a cutout in a transverse face of the housing.

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