Positioning geared motor unit

Abstract

The invention relates to an actuator comprising a housing, an electric motor having an output pinion driving an output wheel via at least one intermediate mechanical transmission member, each member being formed by a coaxial assembly of a toothed input wheel and a toothed output wheel coupled to each other, the axes of the intermediate mechanical transmission members and the axis of the output wheel being parallel and perpendicular to the bottom and to the cover of the housing, the output wheel being guided by a shaft, which shaft is an integral part of the housing or of the cover and extends perpendicularly to the bottom of the housing, a target being disposed facing a probe integrated into a printed circuit, characterised in that the peripheral wall of the shaft has a cutout extending over a tubular arc of less than 120°, and in that the printed circuit has an extension housed inside the shaft, which extension is connected to the printed circuit by a narrow strip that extends through the cutout, the probe being integrated into the extension of the printed circuit housed inside the shaft, the printed circuit extending as far as a peripheral area of the housing or of the cover forming a connector.

Description

Positioning geared motor Scope of the invention

[0001] The present invention relates to the field of geared motors, and more particularly to geared motors intended for automotive applications, involving high robustness and a design limiting maintenance and size.

[0002] Such geared motors typically include an electromagnetic section, with a permanent magnet rotor and a wound stator, controlled by an electronic circuit. A magnetic sensor provides a signal used by the electronic circuit to control the electromagnetic section.

[0003] A gear train transmits the rotor's motion to an output shaft.

[0004] A magnetosensitive probe mounted on a printed circuit board is positioned opposite one front end of the output wheel, to provide information on the actual position of this output. State of the art

[0005] The prior art is known in US patent application 2022 / 037959, which describes a guide element for electric motors used to precisely position a position sensor relative to a rotating element (such as a magnet mounted on the output shaft). It features a compact structure that facilitates alignment between a sensor (particularly a Hall effect sensor) and a magnetic target, thanks to an integrated mechanical device that provides support and guidance. This prior art solution aims to improve the accuracy of angular position detection while simplifying assembly. It specifically addresses alignment and stability issues between the sensor and the rotating element in compact geared motors. Disadvantages of prior art

[0006] Existing prior art solutions, particularly those described in US patent application 2022 / 037959, aim to improve sensor positioning relative to a rotating target within compact geared motors. However, these solutions remain complex to assemble in automated industrial production. Specifically, this patent application relies on a number of separate components that must be assembled sequentially to ensure sensor guidance and alignment, which can lead to cumulative tolerances affecting positioning accuracy. Furthermore, the mechanical stability of the sensor over time, under the effects of vibration or mechanical stress, is not sufficiently robust to guarantee long-term measurement stability.Finally, the integration of additional parts dedicated to guidance or fixing increases the cost of production and limits the possibilities of compactness, which is detrimental in highly constrained environments, such as the automotive sector. Solution proposed by the invention

[0007] In order to overcome the disadvantages of the prior art, the present invention relates to an actuator having the characteristics stated in claim 1 in particular.

[0008] It generally relates to an actuator comprising a housing, an electric motor having an output pinion driving an output wheel by means of at least one moving part each formed by a coaxial assembly of an input gear and an output gear coupled together, the axes of said moving parts and the axis of said output wheel being parallel and perpendicular to the bottom and the cover of said housing, said output wheel being guided by a shaft, said shaft being an integral part of the housing or of said cover and extending perpendicularly to the bottom of said housing, a target arranged opposite with a probe integrated into a printed circuit board.The peripheral wall of said barrel has a cutout extending over a tubular arc of less than 120°, and in that said printed circuit board has an extension housed inside said barrel, said extension being connected to the printed circuit board by an isthmus extending through said cutout, said probe being integrated into the extension of the printed circuit board housed inside said barrel, said printed circuit board extending to a peripheral area of ​​said housing or cover forming a connector.

[0009] In particular, it relates to a positioning and locking mechanism having all or part of the following characteristics.

[0010] The said barrel has stiffeners, such as ribs, extending on either side of the said cutout, between the transverse wall of the case and the peripheral wall of the said barrel.

[0011] The said printed circuit board having traces for the connection of the wires of the windings of said electric motor.

[0012] The said cutout has, on its two edges, a notch or shoulders, to ensure the clipping of the said electronic circuit in a reference position.

[0013] The median plane of the cut, parallel to the axes, forms an angle of less than 60° with the plane defined by the axis of the output wheel guide shaft and the axis of rotation of the upstream moving stage.

[0014] The said cut passes through the plane defined by the axis of the guide shaft of the output wheel and the axis of rotation of the upstream moving part.

[0015] The axis of said electric motor is parallel to the axes of said moving parts and to the axis of said output wheel.

[0016] The axis of said electric motor is perpendicular to the axes of said moving parts and to the axis of said output wheel.

[0017] The invention also relates to a motorized valve system incorporating an actuator incorporating the general characteristics mentioned above and all or part of the additional characteristics.

[0018] Detailed description of a non-limiting example of implementation

[0019] The present invention will be better understood upon reading the following description, concerning a non-limiting example of an embodiment illustrated by the accompanying drawings where:

[0020] Figure 1 represents an exploded view of an example embodiment of an actuator according to the invention.

[0021] Figure 1 represents a front view of an example embodiment of an actuator according to the invention.

[0022] The figure represents a cross-sectional view, along a plane passing through the rotor axis and the output axis, of an example embodiment of an actuator according to the invention.

[0023] Figure 1 represents a front perspective view of an example embodiment of an actuator according to the invention, without its cover and output wheel.

[0024] This represents a rear perspective view of an example embodiment of an actuator according to the invention.

[0025] The figure represents a front perspective view of a variant embodiment of an actuator according to the invention, without its cover.

[0026] This represents a rear perspective view of the presented embodiment variant without its housing and output wheel. General principle of the invention

[0027] The invention is to be appreciated through figures 1 to 5, it relates to an actuator comprising a housing (100) with a cover (110), an electric motor (200) having a rotor (210) having a pinion (310) driving an output wheel (350) by means of a kinematic chain (300), or reduction chain, comprising one or more reduction stages made by means of mobiles (320, 330, 340) formed for each a coaxial assembly of an input gear and an output gear coupled together.

[0028] For the purposes of this patent, "moving parts" refers to an intermediate mechanical transmission component located between the motor output pinion and the output wheel (350). This is a sub-assembly of gears, generally used in the stages of a reduction gear train. In the examples described, each moving part is more precisely defined as consisting of a coaxial assembly comprising an input gear (receiving the motion) and an output gear (transmitting it to the next stage or the final wheel). These moving parts enable the speed reduction and torque increase typical of a multi-stage gearbox.

[0029] The moving parts (320, 330, 340) serve to transmit the motor's motion to the output wheel (350), to reduce the motor's rotational speed while increasing the torque, and to ensure mechanical alignment thanks to their coaxial mounting, which facilitates the system's compactness. They therefore form intermediate components of the actuator's kinematic chain.

[0030] The axis (101) of the rotor (210) of the electric motor, the axes (102, 103, 104) of the moving parts (320, 330, 340) and the axis of the output wheel (350) are parallel and perpendicular to the transverse bottom (150) of said housing (100) and to the cover (110).

[0031] Perpendicular to the transverse base of the housing and the lid means that the axes of the moving parts are distributed in a plane and that the housing and lid have a greater overall extent along this plane. This does not imply that the base of the housing or the lid are perfectly flat, nor that there is at least one surface of the base of the housing or the lid that is perfectly orthogonal to these axes.

[0032] The output wheel (350) is guided by a shaft (165) extending perpendicularly to the bottom (150) of the housing (100) or to the cover (110), said shaft (165) being an integral part of the housing (100) or the cover (110). The output wheel (350) has a target (351) positioned at the front end of the output wheel shaft (350), opposite a probe (405) integrated into a printed circuit board (400) so as to measure the angular position of the output wheel.

[0033] The invention relates more particularly to the configuration of the barrel (165) and the printed circuit board (400) to allow easy automatic assembly, without requiring excessive precision in the positioning of the printed circuit board (400) relative to the barrel (165), and robust positioning of the probe (405) relative to the front end of the output wheel (350).

[0034] To this end, the peripheral cylindrical wall (160) of the shaft has a cutout (155) extending over a tubular arc of less than 120° so as to maintain a guiding function for the output wheel (350), while leaving an opening for the passage of a section of the printed circuit board (400) supporting the probe (405) and for the passage of the electrical connection traces between this probe (405) and the rest of the printed circuit board (400). This cutout (155) preferably extends over a tubular arc of less than 90° to improve the absorption of the transverse forces applied to the output wheel (350) by the preceding stage of the reduction chain. More generally, minimizing the cutout is desirable to improve the robustness of the shaft (165) and its service life, but it must be wide enough to accommodate an isthmus (410) for the electrical routing of the probe (405) and must have good mechanical resistance to vibrations.

[0035] The printed circuit board (400) has an isthmus (410) passing through the cutout (155) in the barrel (165) and extending inside the barrel (165). The probe (405) is mounted at the end of the isthmus (410), on the extension (420) of the printed circuit board housed in the barrel (165), centered on the longitudinal axis of the barrel (165). The printed circuit board (400) extends to a peripheral area of ​​the housing (100) towards a connector (140).

[0036] This design allows for precise positioning of the probe, in particular by providing a cutout (155) sized for passage with a small gap in the isthmus (410) and easy assembly, the printed circuit board being able to be brought by a movement in a direction perpendicular to the bottom (150) of the housing (100), to be positioned against the bottom (150) after passing through the cutout (155).

[0037] Optionally, the inner and / or outer surface of the barrel may have a shoulder to support the lower surface of the printed circuit board (400). The inner and / or outer surface of the barrel (165) may also have a shoulder that is elastically or plastically deformable to hold the printed circuit board (400) by clipping or interference.

[0038] Furthermore, the bottom of the case (150) may have shoring ribs (158) for the support of the printed circuit board (400).

[0039] The printed circuit board (400) is also advantageously connected to the bottom (150) of the case, or to the cover (110), by riveting.

[0040] The target (351) is mounted within the output wheel (350), but is not necessarily fixed to the latter, the output wheel may have a through shaft to couple to a shaft, the probe being fixed at the end of this shaft. Barrel rigidity

[0041] The shaft (165) supports the forces transmitted to the output wheel (350) by the driven element. In order to compensate for the loss of rigidity resulting from the cutout (155), ribs (157) extend between the bottom (150) of the housing and the shaft (165), at least in the area diametrically opposite the cutout (155), and in particular on either side of the cutout (155).

[0042] To reduce deformations that may result from transverse forces applied by the output wheel (350), the cutout (155) in the shaft (165) has a median plane parallel to the axes (101, 102, 103, 104), which forms an angle of less than 60° with the plane (600) passing through the axis of the shaft (165) of the output wheel (350) and through the axis (104) of the moving part driving the output wheel (350). Preferably, the plane (600) passes through said cutout (155), but may also be located near said cutout (155) when the latter has a small angular extent.

[0043] The guide shaft (165) and its ribs (157) are preferably formed integrally with the housing (100) or the cover (110) by a material injection molding process, preferably using plastic. It is also envisaged that, instead of the ribs (175), the guide shaft may be reinforced by a perforated metal ring embedded in the shaft by overmolding during the plastic injection molding process; this metal ring may also be left unembedded in the plastic on its inner or outer surface. Stator positioning

[0044] The assembly is carried out by first inserting the printed circuit board (400) into the bottom of the housing (100), guided by a pin (151) on the housing bottom that fits into a hole in the printed circuit board (400). The printed circuit board (400) is then secured to the bottom (150) by crimping and pressing the connection with pins (145) shaped like a needle's eye, which are pressed into the corresponding tin-plated holes (445) provided in the printed circuit board (a "press fit"). These pins (145) are located on the connector (140) that passes through the side wall of the housing (100). The guide pin (151) is preferably located near the shaft (165) of the output wheel to improve the positioning accuracy of the extension (420) of the printed circuit board (400) housed in the shaft (165) and carrying the probe (405).

[0045] Once the printed circuit board (400) is in place, the moving parts (320, 330, 340) and the rotor are put in place by inserting the pairs of gears onto the shafts fitted into barrels (161 to 165; 111 to 115) respectively on the bottom (150) of the case (100) and on the cover (110).

[0046] The stator (220) of the motor (200) is connected to the printed circuit board (400) and secured to the housing (100). It is guided by a guide rod (152) extending perpendicularly to the bottom (150) of the housing (100). This guide rod (152) passes through a bore provided in the stator laminations, with a fit offering minimal or no clearance. A second guide rod (153), diametrically opposite the first guide rod (152), ensures optimal positioning of the stator (220). The "needle-like" ("pressfit") pins of the stator (220) coils (230) are, during this operation, engaged in the ad-hoc tinned holes of the printed circuit board (400) to ensure the electrical connection and the mechanical positioning of the stator (220), the stator then being held in place by screws inserted into screw bushings (154) or riveting rods (156) of the housing (100) or by clipping or interference (not shown).

[0047] The rotor (210) is then engaged in the stator (220), by insertion onto a shaft (101) fitted into a guide barrel (161) of the bottom (150) of the housing (100).

[0048] The output wheel (350) is then put in place before closing the cover (110).

[0049] The output wheel (350) has a hollow, non-through hub (355) whose bottom is closed by a wall (354) carrying the target (351). The target can be held in place by any means known to those skilled in the art, such as overmolding, gluing, clipping, stapling, or interference. The inner wall of the barrel advantageously has coupling grooves (356) with a complementary component.

[0050] Alternatively, the hub (355) is hollow with a through channel. In this case, the target (351) is mounted at the front end of the shaft of the driven element and comes into view of the probe through the open bottom of the hub (355). Variant to the orthogonal rotor axis

[0051] Figures 6 and 7 illustrate an alternative embodiment of an actuator according to the invention. Figure 1 shows a top perspective view with the cover removed, and Figure 2 shows a bottom view with the housing base and output wheel removed. This embodiment differs from the previous embodiment in that the axis (101) of the rotor (210) of the electric motor (200) is perpendicular to the axes (102, 103) of the moving parts (320, 330) of the drive train (300) and to the axis of the output wheel (350). The coupling between the rotor (210) and the drive train (300) is achieved by means of a worm gear (360) fixed to the rotor (210) meshing with the toothed wheel of the first moving part (320). The electric motor has two electric coils arranged on teeth separated angularly by an angle greater than 150° so as to offer a reduced footprint in the direction of the bisector of the wound teeth, which allows for a thin actuator.

[0052] This embodiment also differs in that the electronic board (400) is located under the cover (110) and partly housed in the shaft (165) of the output wheel guide (350), said shaft being an integral part of the cover (110).

[0053] In the embodiments presented, the rotor axis is parallel or orthogonal to the axes of the moving parts of the kinematic chain, but a person skilled in the art could also imagine variants for which the rotor axis would have an intermediate direction, by using oblique teeth integrated either into the wheel or worm gear attached to the rotor, or into the wheel of the first moving part of the reduction chain. Variants

[0054] In the example shown in the various figures, the probe (405) is magnetosensitive, such as a Hall effect probe, and is positioned opposite a magnetic target (351). However, those skilled in the art could easily consider alternatives, such as an inductive sensor interacting with an electrically conductive target, or more generally any type of position sensor providing an electrical signal and capable of interacting with a distant target.

[0055] The positioning and retention of the extension (420) of the printed circuit board (400) located in the shaft (165) of the output wheel (350) can be done by means of shoulders (159), or notches, located on the lateral faces of the shaft (165), or on the edges of said cutout (155), to clip said electronic circuit (400) into a reference position.

[0056] The actuator can be integrated into a complete functional equipment; for example, a motorized valve.

[0057] Summary of the main characteristics common to all variants

[0058] In summary, the actuators according to the invention make it possible to achieve an integrated, precise, compact and mechanically reliable positioning of a position sensor, while simplifying assembly and reducing manufacturing costs thanks to a printed circuit board isthmus (410) (400) which passes through a cutout (155) made in the wall of a barrel (165) and a guide barrel (165) integral with the housing (100) or the cover (110), made for example by plastic injection, with a probe (405) integrated on an extension of the printed circuit board, which is housed inside the guide barrel (165).

[0059] This arrangement produces several combined technical effects, including: Precise and stable angular positioning of the probe: Integrating the probe (405) into a rigid extension of the printed circuit board (400) inserted into the barrel allows for robust axial alignment between the target and the sensor (405). The passage of the isthmus (410) through a narrow cutout limits backlash tolerances and improves positioning reproducibility. Ease of automated assembly: The barrel and cutout assembly allows for translational mounting of the printed circuit board along a single degree of freedom, which is compatible with robotic assembly lines. The isthmus acts as a natural insertion guide for the printed circuit board extension (400). Reduced component count and size: The integrated barrel eliminates the need for an additional sensor mount.Direct integration into the housing ensures compactness and mechanical robustness, useful in vibratory environments. Better mechanical and vibration resistance: The embedding of the sensor (405) in the barrel via the extension limits the effects of lateral vibrations and ensures an increased lifespan of the detection device.

[0060] These characteristics therefore make it possible to achieve an integrated, precise, compact and mechanically reliable positioning of a position sensor, while simplifying assembly and reducing manufacturing costs, which constitutes a marked industrial advantage compared to the multi-element configurations of the prior art.

Claims

An actuator comprising a housing (100), an electric motor (200) having an output pinion driving an output wheel (350) via at least one moving part (320, 330, 340), each formed by a coaxial assembly of a coupled input gear and output gear, the axes (102, 103, 104) of said moving parts (320, 330, 340) and the axis of said output wheel (350) being parallel and perpendicular to the bottom (150) and the cover (110) of said housing, said output wheel (350) being guided by a shaft (165), said shaft (165) being an integral part of the housing (100) or of said cover (110) and extending perpendicularly to the bottom (150) of said housing (100), a target (351) arranged opposite a probe (405) integrated into a printed circuit board (400), characterized in that the peripheral wall of said barrel (165) has a cutout (155) extending over a tubular arc of less than 120°,and in that said printed circuit board (400) has an extension (420) housed inside said barrel (165), said extension being connected to the printed circuit board (400) by an isthmus (410) extending through said cutout (155), said probe (405) being integrated into the extension (420) of the printed circuit board (400) housed inside said barrel (165), said printed circuit board (400) extending to a peripheral area of ​​said housing (100) or of the cover (110) forming a connector. Actuator according to claim 1 characterized in that said shaft (165) has stiffeners, such as ribs (157), extending, on either side of said cutout (155), between the transverse wall of the housing (100) and the peripheral wall of said shaft (165). Actuator according to claim 1 characterized in that said printed circuit (400) has tracks for connecting the wires of the windings of said electric motor (200). Actuator according to claim 1 characterized in that said cut has, on its two edges, a notch or shoulders (159), to ensure the clipping of said electronic circuit (400) in a reference position. Actuator according to claim 1 characterized in that the median plane of the cut (155), parallel to the axes (101, 102, 103, 104), forms an angle of less than 60° with the plane (600) defined by the axis of the barrel (165) of guide of the output wheel (350) and the axis (104) of rotation of the upstream mobile. Actuator according to claim 1 characterized in that said cutout (155) passes through the plane (600) defined by the axis of the barrel (165) of guide of the output wheel (350) and the axis (104) of rotation of the upstream mobile. Actuator according to claim 1 characterized in that the axis (101) of said electric motor is parallel to the axes (102, 103, 104) of said mobiles (320, 330, 340) and to the axis of said output wheel (350). Actuator according to claim 1 characterized in that the axis (101) of said electric motor is perpendicular to the axes (102, 103, 104) of said moving parts (320, 330, 340) and to the axis of said output wheel (350). Motorized valve system incorporating an actuator according to claim 1.

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