FR2996953A1 - Monostable electromagnetic actuator for use in electric power metering system, has actuation arms bearing coils in magnetic field generated by magnet, and magnetic biasing device permanently biasing arms toward stable configuration - Google Patents

Abstract

The actuator (100) has a main permanent magnet (110), and mobile actuation arms (120a, 120b) bearing electric coils (130a, 130b) placed in a magnetic field generated by the principal permanent magnet, where the actuator is configured in such a way that each actuation arm varies between an unstable configuration when a control current greater than a given threshold and a stable configuration when the control current is lower than the threshold. A magnetic biasing device permanently biases the actuation arms toward the stable configuration. An independent claim is also included for an electric consumed electric power metering system.

Description

The invention relates to the field of a monostable electromagnetic actuator comprising a main permanent magnet and at least one movable actuating arm carrying an electric coil placed in the magnetic field generated by the main permanent magnet. The monostable electromagnetic actuator is configured so that the actuating arm varies, in particular by pivoting, between: a first unstable configuration when a control current greater than a determined trigger threshold flows in the coil, and a second configuration stable when the control current is below this trip threshold. The invention also relates to an apparatus for displaying digits comprising at least one encrypted rotary drum and such a monostable electromagnetic actuator ensuring a sequential rotation of the encrypted rotary drum. It also relates to an electric metering system of consumed electric power, comprising such a device.

Currently, a system for counting the electrical power consumed uses a technique conventionally combining an electronic card processing and a mechanical device with rotating display of circular drums with numbers. The invention essentially relates to the field of this mechanical device which comprises a monostable electromagnetic actuator. With reference to FIG. 1, the monostable electromagnetic actuator 10 comprises a main permanent magnet 13 and two movable actuating arms 11. The two arms 11 are articulated by being pivotally mounted on a base 12 around two distinct and parallel axes D.

Each arm 11 carries an electric coil 14 placed in the magnetic field generated by the main permanent magnet 13. The monostable electromagnetic actuator 10 is configured so that the two arms 11 vary by pivoting between a first unstable configuration when a current of control greater than a determined trigger threshold flows in the two coils 14 and a second stable configuration when the control current is below this threshold. The pivoting arms 11 are held spaced from each other in the second stable configuration by a return spring 15 permanently urging the arms 11 to the second stable configuration. This is a spring 15 with free strands. The axes of symmetry of the coils 14 coincide with the arc defined by the rotation of the arms 11. The main permanent magnet 13 is arranged on the axis of symmetry of the movements of the arms 11 at a position such that its main axis is also confused at the point of tangency with the arc described by the axis of symmetry of the two coils 14 located on the pivoting arms 11. Thus, in the second stable configuration corresponding to an open position of the arms 11, the free strands of the spring 15 hold the two arms 11 apart from each other. When the electrical control circuit requires it, via the electronic card, the adapted control current flows through the coils 14. The magnetic field induced by this current has the effect of creating in each coil 14 a mechanical force such that it is attracted by the main permanent magnet 13 located between the two arms 11. The movement of the arms 11 causes, by a suitable motion transmission system, the rotation of the encrypted drums which displays the counting of the electrical power consumed, in particular according to information under the shape of a number of kWh.

Currently, this solution is not entirely satisfactory because of the following two main problems. On the one hand, there are in practice discrepancies between the displayed count and the reality of the power actually consumed. The quality and repeatability of the freewheel return spring is indeed difficult to control on the one hand on the dimensioning aspect but also on its manufacture which generates a geometrical dispersion. These elements are at the origin of non-adjustable dispersions of the forces collected on the end of each return spring strand which contribute to a part of the causes causing the counting differences observed. On the other hand, the mounting of the return spring 15 is problematic because the very small diameter of the spring and its prestressed shape does not predispose to easy assembly. The object of the present invention is to provide a monostable electromagnetic actuator that overcomes the disadvantages listed above, particularly in the context of application concerning a consumed electric power metering system 20 equipped with an apparatus for displaying digits comprising at least one encrypted rotary drum. In particular, an object of the invention is to provide a monostable electromagnetic actuator for simplifying its assembly and reliability of operation and improve accuracy. A first aspect of the invention relates to a monostable electromagnetic actuator comprising a main permanent magnet and at least one movable actuating arm carrying an electric coil placed in the magnetic field generated by the main permanent magnet, the monostable electromagnetic actuator being configured so that the actuating arm varies between a first unstable configuration when a control current above a predetermined threshold flows in the coil and a second stable configuration when the control current is below said threshold. The electromagnetic actuator comprises a magnetic return device urging, in particular permanently, the actuating arm to the second stable configuration.

The magnetic return device may advantageously comprise an auxiliary permanent magnet associated with the coil and carried by the actuating arm so as to be placed in the magnetic field generated by the main permanent magnet. The coil carried by the actuating arm may in particular be flat and ring-shaped and the auxiliary permanent magnet may in particular be arranged in the center of the coil. Preferably, the auxiliary permanent magnet and the main permanent magnet may be configured to exert a reciprocally repulsive force with respect to each other, the main permanent magnet and the coil being configured to exert a force reciprocally attractive to each other when the control current flows in the coil. The intensity of the magnetic field generated by the coil when the control current is greater than the determined threshold may in particular be greater than the intensity of the permanent magnetic field generated by the auxiliary permanent magnet. Said at least one actuating arm can be articulated on a base on which the main permanent magnet is fixedly mounted so that the actuating arm varies from the first configuration to the second configuration or vice versa by pivoting the arm relative to at said base along a given angular stroke ensuring a displacement of the coil from one position to the other relative to the main permanent magnet.

It can be made that in the first and second configurations of the actuating arm, the coil carried by the actuating arm respectively occupies a close position and a position remote from the main permanent magnet.

The monostable electromagnetic actuator may comprise two separate actuating arms arranged so that the coils they carry respectively are disposed on either side of the main permanent magnet.

A second aspect of the invention relates to an apparatus for displaying numerals comprising at least one encrypted rotary drum and such a monostable electromagnetic actuator providing sequential rotation of the encrypted rotary drum. The apparatus may comprise a motion transmission device configured so that the movement of the at least one movable actuating arm of the monostable electromagnetic actuator of the second configuration to the first configuration, or vice versa, causes rotation of said at least one a rotary drum encrypted according to a given angular stroke corresponding to said sequential rotation.

A third aspect of the invention relates to a system for electrical metering of consumed electrical power, comprising such an apparatus and an electronic processing unit generating a control current flowing in the electric coil carried by the at least one actuating arm. mobile of the monostable electromagnetic actuator, the generation of the control signal by the electronic processing unit is a function of the electrical power consumed. Other advantages and features will emerge more clearly from the following description of particular embodiments of the invention given as non-limiting examples and shown in the accompanying drawings, in which: FIG. 1 is a view of a monostable electromagnetic actuator according to the prior art, - Figures 2 and 3 are perspective and front views of an example of a monostable electromagnetic actuator according to the invention, - Figure 4 is an exploded view of the 2 to 3, FIGS. 5 to 7 are top views of the actuator according to FIGS. 2 to 4 respectively in the second stable configuration, in the first unstable configuration and in an intermediate configuration between the first and second configurations. and second configurations, and FIG. 8 is a perspective view of an exemplary consumed electric power metering system 20 equipped with a display apparatus. numerals comprising at least one encrypted rotary drum rotated by at least one actuator according to FIGS. 2 to 7. The invention will be described later with reference to FIGS. 2 to 6. A monostable electromagnetic actuator 100 comprises a permanent magnet 110 and at least one movable actuating arm carrying an electric coil placed in the magnetic field generated by the main permanent magnet 110. In the advantageous example shown, the monostable electromagnetic actuator 100 comprises first and second arms articulated actuator 120a, 120b respectively carrying first and second electrical coils 130a, 130b placed in the magnetic field generated by the main permanent magnet 110. The two distinct actuating arms 120a, 120b are arranged so that the coils 130a, 130b they carry respectively are disposed on either side of the main permanent magnet 110. The actuates The monostable electromagnetic system 100 is generally configured such that said at least one actuating arm 120a, 120b varies between a first unstable configuration and a second stable configuration, defined in more detail below. The two arms 120a, 120b are articulated by being pivotally mounted on a base 140 about two separate axes Da, Db and parallel. The main permanent magnet 110 is fixedly mounted on the base 140. The axes of symmetry of the coils 130a, 130b coincide with the arc defined by the rotation of the arms 120a, 120b. The main permanent magnet 110 is disposed on the axis of symmetry of the movements of the arms 120a, 120b at a position such that its main axis is also merged at the point of tangency with the arc defined by the axis of rotation. symmetry of the two coils 130a, 130b located on the arms 120a, 120b pivoting. The presence of the coil associated with each actuating arm ensures that the first configuration is adopted when a control current greater than a determined trigger threshold is flowing in the coil. This is a configuration called "unstable" in the sense that this configuration is not maintained in the absence of control current or in the case where the latter has a too low intensity. On the contrary, in such a case, it is the second so-called "stable" configuration for the same reasons which is then automatically adopted, especially when the control current is below the triggering threshold mentioned above.

In the case of the joint presence of the first and second articulated actuating arms 120a, 120b, the monostable electromagnetic actuator 100 is configured so that the first and second articulated actuating arms 120a, 120b vary by pivoting about the axes Da , Db between the first unstable configuration (Figure 6) when a control current flows in the first and second coils 130a, 130b and a second stable configuration (Figure 5) when the control current is interrupted. In the first unstable configuration, the first and second coils 130a, 130b occupy a first position relative to the main permanent magnet 110. The first position of the coils 130a, 130b advantageously corresponds to a close position, for each of them, by relative to the main permanent magnet 110 (FIG. 6). It may in particular be a first position in contact, for each of them, with the main permanent magnet 110. In the second stable configuration, however, the first and second coils 130a, 130b occupy a second position relative to each other. to the main permanent magnet 110. The second position of the coils 130a, 130b advantageously corresponds to a position remote, for each of them, relative to the main permanent magnet 110 (Figure 5). The passage from the close position to the remote position or reciprocally, for a given coil 130a, 130b is practiced by pivoting the actuating arm 120a, 120b which carries it around the axis Da, Db corresponding. FIG. 7 illustrates an intermediate situation between the first and second configurations, during the passage from one to the other, for example. In other words, said at least one actuating arm varies from the first configuration to the second configuration or vice versa by a pivoting of the arm relative to the base 140 according to a given angular stroke ensuring a displacement of the coil which it carries. a position to the other relative to the main permanent magnet 110.

According to an essential characteristic, the monostable electromagnetic actuator 100 comprises a magnetic return device urging said at least one actuating arm 120a, 120b towards the second stable configuration. This return device operates according to principles of magnetism and ensures the return of said at least one actuating arm to the second stable configuration including permanently. In other words, the displacement of the arms 120a, 120b during the introduction of the circulation of the appropriate control current in the coils 130a, 130b, is due to the creation of a magnetic force by the coils 130a, 130b sufficient for s oppose, that is to say cancel and then override, to the permanent action of the magnetic return device: the intensity of the magnetic field generated by the coil 130a, 130b when the control current is greater than the determined threshold, is greater than the intensity of the permanent magnetic field generated by the auxiliary permanent magnet 150a, 150b. The magnetic return device thus permanently urges the first and second articulated actuating arms 120a, 120b towards the second stable configuration.

Advantageously, the magnetic return device comprises an auxiliary permanent magnet associated with the coil and carried by the actuating arm so as to be placed in the magnetic field generated by the main permanent magnet 110. In other words, the magnetic device of return includes a first auxiliary permanent magnet 150a associated with the first coil 130a and carried by the first actuating arm 120a so as to be placed in the magnetic field generated by the main permanent magnet 110, a first side of the main permanent magnet 110. The magnetic return device comprises a second auxiliary permanent magnet 150b associated with the second coil 130b and carried by the second actuating arm 120b so as to be placed in the magnetic field generated by the main permanent magnet 110, a second side of the main permanent magnet 110. The coil 130a, 130b carried by each actuation arm ent is advantageously flat and ring-shaped; the auxiliary permanent magnet 150a, 150b is then arranged in the center of the coil. Such an arrangement has the advantage of high efficiency and good compactness. A given coil 130a, 130b and the auxiliary magnet associated therewith may further constitute a preassembled assembly.

The auxiliary permanent magnet 150a, 150b and the main permanent magnet 110 are configured so as to exert a reciprocally repulsive force with respect to each other; the main permanent magnet 110 and the coil 130a, 130b are configured so as to exert a mutually attractive force towards each other when the control current flows in this coil. In other words, the orientation of the flow of the two auxiliary magnets 150a, 150b relative to the flow of the main magnet 110 is such that it keeps the two arms 120a, 120b hinged in the separated position.

The control current creates in the two coils 130a, 130b a counter-flux sufficient at a time to cancel the flow of the two magnets 150a, 150b and to be attracted by the main magnet 110, and in fact, causes the movement of the arms 120a, 120b to the first unstable configuration.

This counter flow can be adjusted by changing the control current and in fact, trigger the movement of the arm 120a, 120b exactly at the desired threshold, which is not possible with the solution described in connection with FIG. current in the coils 130a, 130b cancels the counter-flow and indeed, the flow of the two magnets 150a, 150b, as opposed to the flow of the main magnet 110, pushes the arms 120a, 120b to the second stable configuration. This arrangement eliminates any inconvenience related to mounting and dispersions of the return spring in the solution described in connection with Figure 1.

An essential aspect of the invention also relates to a system 200 for electric metering of consumed electrical power (FIG. 8). The counting system 200 comprises: a device 202 for displaying digits, itself comprising on the one hand at least one encrypted rotary drum 201i (i varying from 1 to 5 in the particular example illustrated) and secondly a monostable electromagnetic actuator 100 providing a sequential rotation of the rotary drum (s) encrypted (s) 201i, and an electronic processing unit generating a control current flowing in the electric coil 130a, 130b carried by said at least one operating arm 120a, 120b mobile of the monostable electromagnetic actuator 100. The generation of the control signal by the electronic processing unit is a function of the electrical power consumed, so that the sequential rotation of each rotary drum encrypted 201i also depends directly on the electrical power consumed. The backflow threshold created by the two coils 130a, 130b is adjustable by the control current from the electronic card, thus making it easily adjustable.

Further, the digit display apparatus 202 comprises a motion transmission device suitably configured for movement of said at least one movable actuating arm 120a, 120b of the monostable electromagnetic actuator 100 of the second configuration. to the first configuration, or conversely, causes rotation of said at least one encrypted rotary drum 201i according to a given angular stroke corresponding to its desired sequential rotation.

Claims (11)

REVENDICATIONS1. Monostable electromagnetic actuator (100) comprising a main permanent magnet (110) and at least one movable actuating arm (120a, 120b) carrying an electrical coil (130a, 130b) placed in the magnetic field generated by the main permanent magnet ( 110), the monostable electromagnetic actuator (100) being configured such that the actuating arm (120a, 120b) varies between a first unstable configuration when a control current greater than a predetermined threshold flows in the coil (130a). , 130b) and a second stable configuration when the control current is below said threshold, characterized in that it comprises a magnetic return device urging, in particular permanently, the actuating arm (120a, 120b) towards the second stable configuration . 2. Monostable electromagnetic actuator according to claim 1, characterized in that the magnetic return device comprises an auxiliary permanent magnet (150a, 150b) associated with the coil (130a, 130b) and carried by the actuating arm (120a, 120b). ) so as to be placed in the magnetic field generated by the main permanent magnet (110). 3. Monostable electromagnetic actuator according to claim 2, characterized in that the coil (130a, 130b) carried by the actuating arm (120a, 120b) is flat and ring-shaped and in that the auxiliary permanent magnet (150a , 150b) is arranged in the center of the coil (130a, 130b). 4. Monostable electromagnetic actuator according to one of claims 2 or 3, characterized in that the auxiliary permanent magnet (150a, 150b) and the main permanent magnet (110) are configured so as to exert a mutually repulsive force. relative to one another and that the main permanent magnet (110) and the coil (130a, 130b) are configured to exert a mutually attractive force towards each other when the control current flows in the coil (130a, 130b). 5. Monostable electromagnetic actuator according to claim 4, characterized in that the intensity of the magnetic field generated by the coil (130a, 130b) when the control current is greater than the determined threshold, is greater than the intensity of the permanent magnetic field. generated by the auxiliary permanent magnet (150a, 150b). 6. Monostable electromagnetic actuator according to one of claims 1 to 5, characterized in that said at least one actuating arm (120a, 120b) is articulated on a base (140) on which the main permanent magnet (110). is fixedly mounted so that the actuating arm (120a, 120b) varies from the first configuration to the second configuration or vice versa by pivoting the arm (120a, 120b) relative to said base (140) in a given angular stroke ensuring a displacement of the coil (130a, 130b) from one position to the other relative to the main permanent magnet (110). 7. Monostable electromagnetic actuator according to one of claims 1 to 6, characterized in that in the first and second configurations of the actuating arm (120a, 120b), the coil (130a, 130b) carried by the actuating arm (120a, 120b) respectively occupies a close position and a position remote from the main permanent magnet (110). 8. Monostable electromagnetic actuator according to any one of claims 1 to 7, characterized in that it comprises two separate actuating arms (120a, 120b) arranged so that the coils (130a, 130b) they carry respectively are disposed on either side of the main permanent magnet (110). 9. Apparatus (202) for displaying digits comprising at least one encrypted rotary drum (201i) characterized in that it comprises a monostable electromagnetic actuator (100) according to any one of claims 1 to 8 providing a sequential rotation of the drum rotary encoder (201i). 10. Apparatus according to claim 9, characterized in that it comprises a motion transmission device configured so that the movement of said at least one actuating arm (120a, 120b) of the electrostatic actuator monostable (100) of the second configuration to the first configuration, or vice versa, causes a rotation of said at least one encrypted rotary drum (201i) according to a given angular stroke corresponding to said sequential rotation. 11. System (200) for electric metering of consumed electrical power, comprising an apparatus (202) according to any of claims 9 or 10 and an electronic processing unit generating a control current flowing in the electric coil (130a). 130b) carried by said at least one movable arm (120a, 120b) of the monostable electromagnetic actuator (100), the generation of the control signal by the electronic processing unit being a function of the electrical power consumed .