FR2972844A1 - Rotary bi-stable actuator for switch, has magnetic yoke including two branches, and actuating coil generating magnetic flux for displacement of transverse frame from open position to closed position - Google Patents

Abstract

The actuator has a magnetic circuit including a magnetic yoke (10) having two branches (10A, 10B) interconnected by a transverse frame (12), where the frame connects ends of the branches, and another transverse frame (11) is in contact with other ends of the branches in a stable closing position. An actuating coil (2) generates magnetic flux for displacement of the latter frame from open position to closed position. Each of the other ends of the branches includes contact area with the latter frame and having a profile defined by a line having two juxtaposed sections. An independent claim is also included for a switch.

Description

TECHNICAL FIELD OF THE INVENTION The invention relates to a rotary actuator comprising a magnetic circuit having a magnetic yoke having at least a first and second branches interconnected by a first transverse armature, the first transverse reinforcement connecting the first ends of said branches. A second transverse armature carried pivotally on the first leg between two stable positions, the second transverse armature being in contact with second ends of said at least first and second legs in a stable closed position. At least one actuating coil is intended to generate a magnetic displacement flux to promote the displacement of the second transverse armature from a stable opening position to the stable closing position.

The invention also relates to a contactor comprising an actuator according to the invention and at least one movable contact intended to collaborate with a fixed contact. A drive mechanism is provided for moving the movable contact from an open position to a closed position. STATE OF THE ART Rotating electromagnetic actuators are generally used to operate mechanical control elements. As described in the patent applications (EP 0836212B1, FR 2884039), said mechanical control elements may be intended to control the opening or closing of the contacts of a switching device.

According to a known embodiment and shown in FIG. 1, the bistable actuator comprises a magnetic circuit composed of a magnetic yoke 10 and a transverse reinforcement 11. Said transverse reinforcement 11 is pivotally mounted on an external branch of the E-shaped magnetic circuit between two stable positions. So, more generally, the actuator

comprises a moving part capable of occupying two states: a first state corresponding to the "closed circuit" position in which a moving part is in contact with at least two branches of a magnetic carcass and a second state corresponding to the "circuit" position; open ".

By way of example, each stable position of the armature 11 corresponds to an open or closed electrical state of electrical contacts of a breaking device. The actuators having such a magnetic structure with a pivoting frame exhibit good mechanical stability, and make it possible to reduce the bulk.

To move from the "open circuit" position to the "closed circuit" position, an actuating coil 2 is energized to provide a magnetic displacement flux (Pd then causing the rotational displacement of the transverse armature 11. the magnetic flux generated by the coil passes mainly through a large air gap E related to the stroke of the movable part of the actuator.In terms of power consumption, these rotary actuators have the disadvantage of being relatively ineffective. , the reluctance of the magnetic circuit seen from said actuating coil 2 is relatively large, depending on the magnetic structure of the magnetic circuit 1, the reluctance is strongly dependent on the size of the air gap E between the transverse armature 11 and the magnetic cylinder 10. However, to move from the "open circuit" position to the "closed circuit" position, the ampere-turns necessary for the production of a magnetic flux of displacement sufficient to cancel the magnetic holding flux Om generated by the magnet 3 are proportional to the reluctance seen from the actuating coil 2. SUMMARY OF THE INVENTION The invention therefore aims at remedying disadvantages of the state of the art, so as to provide a rotary actuator with significant closing forces.

The second ends of said at least first and second branches of the magnetic yoke of the actuator according to the invention respectively comprise a contact zone with the second transverse reinforcement, contact zone having a profile defined by line having at least two juxtaposed sections. Preferably, the magnetic yoke comprises a third branch, said branches being interconnected by the first transverse reinforcement via first ends of said branches. According to a development mode of the invention, the profile of each contact zone between the second transverse reinforcement and the second ends of the branches comprises at least one broken line having at least two juxtaposed sections. Preferably, the profile of at least one contact zone comprises at least one broken line having three juxtaposed sections, a main section delimited by two secondary sections, said secondary sections being parallel. Advantageously, said at least two sections are linear. According to a particular embodiment of the invention, the second transverse armature is connected to the first branch of the magnetic yoke by a swivel air gap, the swivel gap being constant regardless of the position of the transverse armature with respect to the magnetic yoke . Preferably, the actuator according to the invention comprises an actuating coil wound around the second central branch of the magnetic yoke. According to an alternative embodiment, the actuator comprises two actuating coils wound respectively around the first and third outer branches of the magnetic yoke. Advantageously, the first, second and third branches are arranged in such a way that the magnetic yoke has an E-shaped section. The second transverse reinforcement of the actuator of the contactor according to the invention comprises a projecting part able to unlock the mechanism. of the contactor and move the movable contact from an open position to a closed position. BRIEF DESCRIPTION OF THE FIGURES Other advantages and features will emerge more clearly from the following description of a particular embodiment of the invention, given by way of non-limiting example, and represented in the accompanying drawings, in which: FIG. 1 shows a schematic sectional view, in an open position, of a bistable rotary actuator according to the state of the art; FIG. 2 represents a schematic view, in an open position, of a rotary actuator according to a first embodiment; FIG. 3 represents a schematic view, in an open position, of a rotary actuator according to a second embodiment; FIG. 4 represents an alternative embodiment of a rotary actuator according to FIG. 1; - Figure 5 shows a schematic view of an electric switch according to a first embodiment. DETAILED DESCRIPTION OF AN EMBODIMENT According to the embodiments of the invention as shown in FIG. 2, the rotary actuator comprises a magnetic circuit having a magnetic yoke 10. Said magnetic yoke 10 comprises at least a first and second branches 10A, 10B interconnected by a first transverse armature 12 connecting first ends of said branches. Said magnetic yoke 10 comprises a second transverse reinforcement 11 carried so as to pivot on the first branch 10A between two stable positions. A contact zone located at the pivot point between the second end of said first branch 10A and the second transverse reinforcement 11 comprises at least one equivalent reluctance known as slip Rg. According to a particular embodiment as shown in Figure 4, the second transverse armature 11 is connected to the first branch of the magnetic yoke by a so-called swivel air gap. The swivel air gap as shown is constant regardless of the position of the transverse armature 11 relative to the magnetic yoke 10. Thus, on a controlled air gap surface, a portion of the so-called sliding slip Rg relative reluctance is then constant at during the displacement of said transverse armature. This gap makes it possible to achieve a holding force between the yoke and the rotating armature. The contact zone between the two parts can be achieved in particular by a calibrated molded part or a suitable surface treatment to facilitate sliding and / or calibrate also the air gap. This swivel air gap function can be ensured by interleaving one end of the transverse armature 11 in the cylinder head 10. The transverse armature then has a rounded protuberance and having a radius sized in such a way that the magnetic bonding forces are self-centering to maintain these two parts without changing the closing torque. This positioning can also be facilitated by the positioning of a holding clip 21 creating an elastic mechanical connection between the magnetic yoke 10 and the transverse reinforcement 11. The second transverse reinforcement 11 is in contact with second ends of said at least first and second branches 10A, 10B in a stable closed position. The rotary actuator comprises at least one actuating coil 2 generating a magnetic displacement flux 1) d intended to move the second transverse armature 11 from a stable opening position to the stable position of closure. According to one embodiment, the actuating coil 2 is wound around the second branch 10B of the magnetic yoke 10. According to a preferred embodiment, the profile of each contact zone between the second transverse reinforcement 11 and the second ends said at least first and second branches 10A, 10B comprises at least one line 30 having at least two juxtaposed sections. In other words, the second ends of said at least first and second branches respectively comprise a contact zone with the second transverse armature having a profile defined by a line having at least two juxtaposed sections. According to the embodiments of the invention, the development of the profile of each contact zone makes it possible to obtain larger air gap surfaces than that present on known actuators. This type of solution is particularly advantageous when the thickness of the magnetic yoke is low for space requirements. The small thickness sought for the actuator is compensated by the optimization of the air gap profiles which increases the working surface In order to reduce the size of the actuator, the actuating coil 10 covers part of the second armature transverse when the latter is in a stable position of closure. As shown in FIG. 2, the second transverse reinforcement 11 then preferably comprises at least first and second branches 11A, 11B. The profile of each contact zone between the second transverse reinforcement 11 and the second ends of the branches comprises at least a broken line having at least two juxtaposed sections. Advantageously, the profile of at least one contact zone comprises at least one broken line having at least three juxtaposed sections. As an exemplary embodiment, the profile preferably comprises a main section delimited by two secondary sections, said secondary sections being substantially parallel. The presence of the secondary sections avoids peak effects that can cause local saturation phenomena of the magnetic circuit at these points. Indeed, the setting in vis-à-vis a secondary section of a branch of the magnetic yoke with a secondary portion present on the second transverse armature 11 allows a larger exchange surface for the passage of the magnetic flux. According to a particular embodiment, said at least two sections are advantageously linear. According to another embodiment of the invention as shown in FIGS. 3 and 4, the rotary actuator comprises a magnetic yoke 10 comprising a third branch 10C. Said branches are interconnected by the first transverse reinforcement 12 misses mark via first ends of said branches. As an exemplary embodiment, the third branch 10C is preferably parallel to the first and second branches 10A, 10B. The third branch 10C is then arranged in such a way that the magnetic yoke 10 has an E-shaped section. The presence of a third gap between the second end of the third branch 10C and the second transverse reinforcement 11 makes it possible to to obtain an additional effort at the end of closing. This additional effort leads to an avalanche effect that can be used for example to break a weld present between the contacts of a contactor. According to an alternative embodiment, not shown, the actuator comprises two actuating coils wound respectively around the first 10A and third outer branches 10C of the magnetic E-shaped 10.

As shown in FIG. 5, the invention also relates to a contactor 100 comprising an actuator as defined above. The contactor further comprises at least one mobile contact intended to collaborate with a fixed contact. A drive mechanism is able to move the movable contact from an open position to a closed position. According to a preferred embodiment, the movement of an opening position to a closed position of the actuator actuates the drive mechanism of the movable contact. The second transverse armature 11 has a projecting portion 111 adapted to unlock the driving mechanism of the contactor. Preferably, the contactor according to the invention comprises a movable contact bridge intended to collaborate with two fixed contacts respectively connected to connection terminals. According to a variant not shown, the magnetic circuit may comprise a magnet generating a magnetic holding flux for maintaining the second transverse armature in one of two stable positions. The magnetic displacement flux is intended to oppose a magnetic flux of maintenance.

Claims (10)

REVENDICATIONS1. Rotary actuator comprising: - a magnetic circuit having a magnetic yoke (10) comprising at least a first and second arm (10A, 10B) interconnected by a first transverse armature (12), the first transverse armature (12) connecting first ends of said branches; a second transverse armature (11) pivotally mounted on the first limb between two stable positions, said second transverse armature being in contact with second ends of said at least first and second limbs in a stable closed position - at least one actuating coil (2) for generating a magnetic displacement flux ((Pd) to promote the displacement of the second transverse armature (11) from a stable opening position to the stable closed position, characterized the second ends of said at least first and second legs (10A, 10B) respectively comprise a contact zone with the second transverse armature (11), contact zone 20 having a profile defined by line having at least two juxtaposed sections. 2. Rotary actuator according to claim 1, characterized in that the magnetic yoke (10) comprises a third branch (10C), said branches being interconnected by the first transverse armature via first ends of said branches. 25 Rotary actuator according to claim 1 or 2, characterized in that the profile of each contact zone between the second transverse reinforcement (11) and the second ends of the branches (10A, 10B, 10C) comprises at least one broken line having at least two juxtaposed sections. 4. Rotary actuator according to claim 3, characterized in that the profile 30 of at least one contact zone comprises at least one broken line having atrois juxtaposed sections, a main section delimited by two secondary sections, said secondary sections being parallel. 5. Rotary actuator according to any one of the preceding claims, characterized in that said at least two sections are linear. 6. Rotary actuator according to any one of the preceding claims, characterized in that the second transverse armature (11) is connected to the first leg (10A) of the magnetic yoke (10) by a swivel air gap, the air gap being constant regardless of the position of the transverse armature (11) relative to the magnetic yoke (10). 7. Bistable actuator according to any one of the preceding claims, characterized in that it comprises an actuating coil (2) wound around the second branch (10B) central magnetic yoke (10). 8. Bistable actuator according to any one of the preceding claims 2 to 7, characterized in that it comprises two actuating coils wound respectively around the first and third outer branches (10A, 10C) of the magnetic yoke (10). ). Rotary actuator according to one of the preceding claims, characterized in that the first, second and third limbs (10A, 10B, 10C) are arranged in such a way that the magnetic yoke (10) has a shaped section. from E. 10. Contactor (100) comprising - an actuator according to the preceding claims, - at least one movable contact (5A) intended to collaborate with a fixed contact (5B), 25 - a drive mechanism (50) of the movable contact (5A). ) from an open position to a closed position, contactor characterized in that the second transverse armature (11) of the actuator comprises a projecting portion (111) able to unlock the drive mechanism (50) of the contactor and moving the movable contact 30 (5A) from an open position to a closed position.