FR2867304A1 - Switching device, has activation mechanism including movable propeller unit which is maintained in contact with transmission unit by utilizing elastic units, when fixed and movable contacts are closed - Google Patents

Abstract

The device has an activation mechanism (3) including a movable propeller unit (13) which is maintained in contact with a transmission unit (10) by utilizing elastic units (11, 12), when fixed and movable contacts (1, 2) are closed. The elastic units (11, 12) act respectively on the transmission unit and on the propeller unit and exert respective forces (F1, F2) which are opposed to each other.

Description

SWITCHING DEVICE COMPRISING AN ULTRA-ACTUATING MECHANISM

FAST

  TECHNICAL FIELD OF THE INVENTION [0001] The invention relates to a switching device comprising a switching part having a fixed contact and a movable contact that can move with respect to said fixed contact between an open position and a position closure and an actuating mechanism responsible for moving the movable contact via a propulsion device acting on a transmission member.

STATE OF THE ART

2] The use of ultra-fast actuating mechanism for opening or closing the contacts of a switching device is described in particular in the patent applications (FR-A-2815611, US2002 / 0044403 A1, W003 / 056586 A1).

3] In known manner, as shown in Figure 1, the switching device comprises a fixed contact 1 cooperating with a movable contact 2. The contacts are respectively connected to the electrical terminals of an external electrical circuit to be switched. The control of opening and closing of the contacts, in other words the movement of the movable contact is actuated by an actuating mechanism 3.

4] The goal sought by such devices is the opening and closing ultra fast contacts.

5] Some solutions provide actuating mechanisms having a conventional Thomson effect thruster. The actuating mechanism 3 is generally composed of a transmission member 10 and a propulsion member 13. The transmission member 10 is essentially composed of a mobile disc 4 connected to the moving contact 2 by a movable shaft 6. The propulsion unit 13 essentially consists of a so-called propulsion coil.

  Generally, the disk 4 is positioned as close as possible to the coil 5. The propulsion coil 5 is fixed relative to the frame 7 of the device.

6] To open the contacts, the drive coil is traversed by an electric current and generates a magnetic field which produces an electromagnetic repulsion force Fp which pushes the mobile disk 4 in a direction parallel to its axis of revolution 8. The displacement of the disc 4 concomitantly causes the displacement of the movable contact 2 and thus the opening of the contacts of the switching device. This type of mechanism is used for its simplicity of implementation as well as for its low cost.

7] Presented in FIG. 2, another solution that is even more efficient than the previous one is to place a second coil 9 in the mobile disk 4. The repulsion forces created by the two coils are then used together for an ultra-fast movement of the coil. movable contact 2 via the second voice coil 9. The two coils are then configured to create opposing electromagnetic repulsion forces. Each coil generates a magnetic field that produces an electromagnetic repulsion force that tends to repel the other coil. Under the combined effect of the two repulsive forces, the voice coil 9 will move even faster. The main advantage of this kind of device is that one can create more intense repulsion forces than in the case of a conventional Thomson effect thruster. The currents do not have to be induced in a secondary such as a disc so that the force of repulsion is expressed. This type of device can be used on an electromechanical breaker with ultra fast opening allowing a very strong limitation of the short-circuit currents.

In addition, the double-coil device can be used in asymmetrical form or with coils of various shapes. It can also be complexified at the level of its electronic control. More sophisticated electronics provide access to more advanced features that allow better control of the device. In particular, it is possible to manage the moving travel of the voice coil which can be slowed down or accelerated in one direction or the other. It is also possible to hold down in position, hold in the high position with an additional electromagnetic return force.

9] The efficiency of the high-speed opening systems depends on the size of the space between the propulsion unit 13 and the transmission member 10 when the contacts are closed. Subsequently, this space is called gap. The aim is to maintain contact with the movable disc of the transmission member 10 and the fixed coil the propelling member 13, in other words to minimize the size of the air gap.

In view of the manufacture of such devices and given the wear of the contacts observed during operation, games are present and the travel movements of the contacts are not constant over time. The presence of these games can be reflected in particular in the length of the air gap between the fixed coil and the mobile disk.

1] When the previously described devices are dedicated to low voltage applications where moving contact moving strokes are relatively reduced compared to the existing global game. A variation in the length of the gap between different manipulations influences the proper functioning of the device. Indeed, given the size of the coils and their ability to produce propulsive forces, the presence of a gap too large before opening, may cause insufficient or too slow opening between the contacts. In addition, the opening time of the contacts varies from one opening to another.

  SUMMARY OF THE INVENTION The invention therefore aims to remedy the disadvantages of the state of the art, so as to provide a stable switching device and avoiding operating drifts.

3] The switching device according to the invention comprises a thruster member of the actuating mechanism, said thruster member is movable and maintained, when the contacts are closed, in contact with the transmission member by means of at least two elastic means acting respectively on said transmission member and on said movable propulsion member, the forces exerted by said resilient means opposing.

4] Advantageously, the force of the elastic means acting on the transmission member is greater than the force of the elastic means acting on the movable propulsion member, and the overall mass of the transmission member is less than mass of the mobile propellant.

Preferably, the ratio of the intensity of the forces exerted by the elastic means is between two and ten and the weight ratio of the propulsion member and the transmission member is between five and one hundred.

6] Preferably, the ratio of intensity of the forces exerted by the elastic means is equal to five and the weight ratio of the propulsion member and the transmission member is equal to ten.

Advantageously, the mobile propellant produces a propulsive force of greater intensity than the forces exerted by said elastic means.

8] Preferably, the movable propellant comprises an electromagnetic actuator consisting of a coil housed in a bolt on which the force of the corresponding elastic means is applied.

9] Preferably, the propulsion force is of intensity at least equal to twenty times and one hundred times the intensity of the forces exerted by the elastic means.

0] Preferably, the transmission member is composed of a movable metal disk positioned facing the coil of said electromagnetic actuator, the axes of revolution of the coil and the disk being merged.

1] The disk of the transmission member comprises a voice coil positioned opposite the coil of said electromagnetic actuator, the axes of revolution of the two coils being merged.

2] In a particular embodiment, the actuating mechanism comprises a second fixed electromagnetic thruster comprising an opening and / or closing coil housed beyond the transmission member, the axes of revolution of the propulsion units fixed and mobile and the transmission member being substantially aligned.

3] According to a development of the invention, the mobile propellant comprises a piezoelectric actuator comprising at least one prestressed piezoelectric element, the movable propulsion member on which the force of the corresponding elastic means applies.

4] Advantageously, a deformation of the piezoelectric elements under the action of a voltage pulse causes the displacement of the transmission member.

5] The deformation of the piezoelectric elements is transmitted to the transmission member via a thrust pin whose ends are respectively in contact with the transmission member and said piezoelectric elements.

6] Preferably, the propulsion force generated by the piezoelectric actuator is greater than the forces produced respectively by the elastic means.

Advantageously, the movable contact 2 is directly placed on the disk of the transmission member 10.

8] A hybrid switch according to a development mode of the invention comprising in parallel a mechanical opening means and an electrical opening means, the mechanical opening means consists of a switching device as defined above.

BRIEF DESCRIPTION OF THE FIGURES

9] 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: FIGS. and 2 are schematic sectional views of prior art devices; FIG. 3 is a diagrammatic sectional view of a device according to one embodiment of the invention in which the contacts are in the closed position; Figure 4 is a schematic sectional view of the device according to one embodiment of the invention wherein the contacts are in the open position; Figures 5 to 10 show alternative embodiments of the device according to one embodiment of the invention.

  DETAILED DESCRIPTION OF AN EMBODIMENT

0] As shown in FIG. 3, the actuating mechanism 3 is composed of a movable propelling member 13 and a transmission member 10.

1] According to one embodiment of the invention, the mobile propellant member 13 comprises an electromagnetic actuator composed of a body, hereinafter referred to as the cylinder head 14 and an electric coil called the propulsion coil 5. The cylinder head 14 of cylindrical shape has a first posterior face 15 and a second anterior face 16. The electric propulsion coil 5 is placed in a bore formed in the rear face 15 of the yoke 14. The upper face of the coil is placed slightly back from at the rear face 15 of the yoke 14. The axes of revolution 8 of the coil 5 and the yoke 14 are merged or aligned.

2] The yoke 14 is connected to the frame 7 of the device by means of elastic means 12. According to the embodiment, the elastic means 12 comprise a helical spring. This spring working in compression exerts a force F2 on the yoke 14 of the movable propulsion member 13 which tends to cause it to move towards the transmission member 10.

3] According to one embodiment of the invention, the transmission member 10 comprises a metal disk 4. The axis of revolution of this disk 8 coincides with that of the cylinder head 14. The lower surface of the disk 4 is placed in facing relation with the rear face 15 of the yoke 14. In the exemplary embodiment, the outer diameter of the disk is at least equal to the outside diameter of the coil 5.

4] The disk 4 is connected to the frame 7 of the device via elastic means 11. According to this embodiment, the elastic means 11 comprise a helical spring. This spring working in compression exerts a force F1 on the disc 4 of the transmission member 10 which tends to cause it to move towards the propulsion member 13.

5] The compression forces F1 and F2 are in opposition and tend to stick the underside of the disc on the rear face 15 of the yoke 14.

6] According to the embodiment, when the electrical contacts 1, 2 of the switching portion 17 are closed, the disc 4 and the yoke 14 are in contact, the air gap between them is zero. The device is then in a stable state called closure.

7] The movable contact 2 of the switching part 17 is connected to the mobile disk 4 of the actuating mechanism 3 via a movable shaft 6. Thus, the translational movement of the mobile disk 4 along its axis of revolution 8 is integrally transmitted to the moving contact 2 which moves along the same axis. The movable shaft 6 is integrally mounted to the transmission member 10.

8] When the device is in its stable state of closure, the elastic means 11 acting on the mobile disk 4 are chosen so as to exert a force F1 which is much greater than the force F2 exerted by the elastic means 12 acting on the yoke 14. In addition, the overall mass M2 of the mobile propulsion unit 13 is much greater than the overall mass M1 of the transmission member 10 formed mainly by the disc 4, the movable shaft 6 and the movable contact 2 By way of example, the intensity of the forces F1 and F2 are respectively equal to ten and two Newtons. F2 is preferably 20 percent F1. By way of example, the masses M1 and M2 are equal to 4 and 40 grams, respectively. The mass M2 is preferably equal to the mass M1. Preferably, the intensity ratio of the forces F1, F2 exerted by the elastic means 11, 12 is between two and ten and the ratio of the masses M1, M2 of the propulsion member 13 and the transmission member 10 is between five and one hundred.

9] The operation of the switching device according to a first embodiment is as follows.

0] When the contacts 1 and 2 of the switching device are closed, as shown in Figure 3, a current pulse sent in the propulsion coil 5 of the yoke 14 produces a magnetic field that generates a propulsive force Fp acting on the disk 4. A force Fp 'due to a feedback effect, of intensity equal to Fp, is applied to the cylinder head 14. The electric pulse is delivered by a particularly pulsed energy source which can consist of a previously loaded capacitor.

1] When sending the electric current pulse in the coil 5, that is to say when the device will leave its stable state of closure, the intensity of the forces Fp and Fp 'is much greater than the intensities forces exerted by the elastic means 11 and 12 (Fp F1 and Fp 'F2). By way of example, the intensity of the propulsion force Fp is respectively twenty-five times and one hundred and twenty-five times the intensity of the forces F1 and F2.

2] The propulsion forces applying respectively to the transmission member 10 and the movable propulsion member 13 oppose the compression forces F1 and F2. Thus, said forces F1 and F2 tend to attach the disk 4 of the transmission member 10 to the yoke 14 of the thruster member 13, and the forces Fp and Fp 'tend to take off said members.

3] Given the respective values of the forces in presence (F1, F2, Fp, Fp '), the disc 4 and the yoke 14 are respectively spaced apart from each other with accelerations 71 and y2. The accelerations 71 and 72 depend directly on the masses M1 and M2 as well as the propulsion forces Fp and Fp '. 3o The following equations are obtained: [0044] Fp = M1E1 and Fp '= M2E2 Given that the mass M2 is much greater than the mass M1, the acceleration y1 of the mobile disk 4 associated with the contact mobile 2 is greater than the acceleration y2 of the movable propulsion member 13. Thus the displacement of the yoke 14, proportional to its acceleration, is very low and slow compared to that of the movable contact 2. One thus obtains an opening Very fast of the movable contact 2. For example, the values of the accelerations yl and y2 are respectively 60000 meters per second squared (60000 m / s2) and 6200 meters per second squared (6200 m / s2). This corresponds approximately to 6118 times the acceleration of gravity for the acceleration y1 and 632 times for the acceleration y2. The maximum speed V1 of displacement of the transmission member 10 is three meters per second (3 m / s) on a displacement of X1 of two millimeters.

6] When the coil 5 is no longer powered, the propulsion force Fp is zero. The force F1 exerted by the elastic means 11 acting on the transmission member 10 allows the movable contact 2 to come into contact with the fixed contact 1. The contacts 1 and 2 of the switching portion 17 are closed again and the device regains a stable state of closure.

7] The force F2 exerted by the elastic means 12 acting on the propulsion member 13 allows the cylinder head 14 to come into contact with the mobile disk 4. The displacement stroke of the cylinder head along the axis 8, is sufficient to compensate wear on contacts 1 and 2 or residual clearance. Thus, whatever the wear of the contacts and the games present in the device, the air gap is again zero after this opening and closing sequence.

8] According to an alternative embodiment, shown in Figure 5, the elastic means 11 are placed directly on the movable contact 2 and exert their action directly on the latter.

9] According to another embodiment, the mobile disk 4 may contain a coil 9. The operation of the switching device according to this embodiment shown in Figure 6 is as follows.

0] In order to open the contacts, a current pulse is sent both in the propulsion coil 5 and in the voice coil 9. The supply of the two coils is carried out so that the magnetic fields created by said coils, generate propulsive forces of opposite directions. The overall effect resulting from the presence of these two forces then tends to move the disk 4 away from the bolt 14.

1] At the sending of the electric current pulse in the coils 5 and 9, that is to say when the device will leave its stable state of closure, the intensity of the resulting forces FP and FP 's' applying respectively to the transmission member 10 and the propulsion member 13 is much greater than the intensities of the forces exerted by the elastic means 11 and 12, for example FP F1 and FP 'F2. Forces FP and FP 'oppose compression forces F1 and F2. Given that said forces F1 and F2 tend to attach the disk 4 of the transmission member 10 to the yoke 14 of the propulsion unit, the FP and FP 'forces tend to take off said bodies. An opening of the moving contact is thus obtained even faster than in the previous embodiment. By way of example, the force FP and the acceleration y1 can respectively reach 350 newtons and 87500 meters per second squared (87500 mIs2). The maximum speed V1 of displacement of the transmission member 10 can reach 5 meters per second (5 m / s) on a displacement X1 of 4 millimeters.

2] When the coils 5 and 9 are no longer powered, the propulsion forces FP and FP 'are zero. The respective forces F1 and F2 of the elastic means 11 and 12 acting on the movable elements of the actuating member allow the transmission member 10 to come into contact with the propulsion member and simultaneously allow the closure of the contacts 1 and 2 of the switching part 17.

3] In order to further increase the moving speed of the moving contact, a second fixed electromagnetic thruster can be used in the actuating mechanism. According to FIG. 7, a third fixed coil 20 is then placed between the mobile disk 4 and the building 7. Depending on the direction of the current flowing in the coil 20, the magnetic field created by the coil 20 generates an attractive force which tends to attract the movable disk 4 to said coil 20 and away from the cylinder head 4. Thus, this attraction electromagnetic force can be used for the purpose of quickly opening the contacts. In addition, this attraction force can keep the contacts in the open position.

4] According to another embodiment, the disc 4 of the transmission member 10 and the movable shaft 6 are in contact but are not integrally mounted.

5] Advantageously according to FIGS. 8 and 9, in order to reduce the size and size of the switching device, it is possible to directly position the moving contact 2 on the mobile disc 4 of the transmission member 10. A hole is arranged in the yoke 14 to pass the fixed contact 1 shown in this example in the form of at least two electrodes.

6] According to another exemplary embodiment shown in FIG. 10, the mobile propellant member 13 of the actuating mechanism 3 is composed of a piezoelectric actuator comprising a piezoelectric block 30 and a propellant shaft 33. This piezoelectric block 30 comprises a stacking piezoelectric elements 31. This stack is produced along the axis of displacement 8 of the movable contact 2. These piezoelectric elements 31 are mounted prestressed in a space arranged in the propulsion unit 13. In the exemplary embodiment, the prestressing piezoelectric elements is made by elastic means 32 such as a compressed coil spring. Adjustment means may be used to more or less compress this spring and thus vary the prestressing force exerted.

7] In this exemplary embodiment, the movable contact 2 is directly placed on the mobile disc 4 of the actuating member 10. The propulsion shaft 33 connects the propulsion member 13 to said movable contact 2. This axis has a first end in contact with the rear face of the piezoelectric block 30 and a second end in contact with the movable contact 2. The thruster shaft 33 is slidably mounted in an opening in the propulsion unit.

  Thus, when the electrical contacts let 2, according to FIG. 9, are closed, the propellant shaft 33 has a first part outside the propulsion unit and a second part inside the space in which is positioned the piezoelectric block.

8] The length of the stack of the elements 31 forming the piezoelectric block 30 is directly proportional to the length of the displacement of the propellant axis. Indeed, under a supply voltage Vc, the piezoelectric block 30 will deform more or less depending on the number of prestressed elements forming said block. This sudden deformation causes an ultra-rapid displacement of the thrust pin 33 which will then take off the movable contact 2 of the fixed contact 1.

9] As for the examples described above, the propulsion force Fp produced by the propulsion unit is greater than the force F1 produced by the elastic means 11. The force FP 'generated by a feedback effect is also greater than the F2 force produced by the elastic means 12 acting on the movable propulsion member 13. The propellant will therefore be able to move in a direction opposite to that of the movable contact 2.

0] As soon as the piezoelectric block returns to its original shape, the forces produced by the elastic means F1 and F2 are responsible for the return to equilibrium of the device. The movable contact 2 returns in position against the fixed contact 1. In addition, despite possible wear of the contacts, the contact is again established between the propellant shaft 33, the piezoelectric block 30 and the movable contact 2. In fact, as for the first embodiment using an electromagnetic actuator, the fact that the propulsion member 13 is movable and can move along the axis 8, the contact between the transmission member 10 and the propulsion member 13 is still established when contacts 1 and 2 are closed.

1] Thus, the gap between the transmission member 10 and the propulsion member 13 is always zero when the contacts are closed and the efficiency of the ultra-fast switching device is optimal at the time of opening.

Claims (16)

  Switching device comprising a switching part (17) having a fixed contact (1) and a movable contact (2) movable with respect to said fixed contact (1) between an open position and a closed position and an actuating mechanism (3) responsible for the displacement of the movable contact (2) via a propellant (13) acting on a transmission member (10), characterized in that the propulsion member (13) ) of the actuating mechanism (3) is movable, and is maintained, when the contacts (1) and (2) are closed, in contact with the transmission member (10) by means of at least two elastic means (11, 12) acting respectively on said transmission member (10) and on said movable propulsion member (13), the forces (F1, F2) exerted by said resilient means opposing.   2. Switching device according to claim 1 characterized in that the force (F1) of the elastic means (11) acting on the transmission member (10) is greater than the force (F2) elastic means exerting on the mobile propellant (13), and that the overall mass (Ml) of the transmission member (10) is less than the mass (M2) of the movable propulsion member (13).   3. Switching device according to claim 2 characterized in that the intensity ratio of the forces (F1) and (F2) exerted by the resilient means (11, 12) is between two and ten and the ratio of masses (M2 , M1) of the propellant (13) and the transmission member (10) is between five and one hundred.   4. Switching device according to claim 3 characterized in that the intensity ratio of the forces (F1) and (F2) exerted by the elastic means (11, 12) is equal to five and the mass ratio (M2, M1 ) of the propellant (13) and the transmission member (10) is equal to 10.   5. Switching device according to any one of the preceding claims characterized in that the movable propellant (13) produces a propulsive force (Fp) of intensity greater than the forces (F1) and (F2) exerted by said means elastics (11, 12).   6. Switching device according to claim 5 characterized in that the intensity of the propulsion force (Fp) is at least equal to twenty times and one hundred times the intensity of the forces (F1, F2) exerted by the means elastics (11, 12).   7. Switching device according to any one of the preceding claims 1 to 3 characterized in that the movable propellant (13) comprises an electromagnetic actuator consisting of a coil (5) housed in a bolt (14) on which the force (F2) of the corresponding elastic means (12) is applied.   8. Switching device according to any one of the preceding claims 1 to 3 characterized in that the transmission member (10) is composed of a movable metal disk (4) positioned facing the coil ( 5) of said electromagnetic actuator, the axes of revolution of the coil (5) and the disk (4) being merged.   9. Switching device according to claim 8 characterized in that the disk of the transmission member (10) comprises a voice coil (9) positioned opposite the coil (5) of said electromagnetic actuator, the axes revolution of the two coils being merged.   10. Switching device according to any one of the preceding claims characterized in that the actuating mechanism (3) comprises a second fixed electromagnetic thruster comprising a coil (20) opening and / or closure housed beyond the transmission member (10), the axes of revolution of the fixed and mobile propellant members and the transmission member (10) being substantially aligned.   Switching device according to any one of the preceding claims, characterized in that the movable propulsion device (13) comprises a piezoelectric actuator comprising at least one prestressed piezoelectric element (31), the movable propulsion device (13) on which the force (F2) of the corresponding elastic means (12) is applied.   12. Switching device according to claim 11 characterized in that the deformation of the piezoelectric elements (31) under the action of a voltage pulse (Vc) causes the displacement of the transmission member (10).   13. Switching device according to claim 12 characterized in that the deformation of the piezoelectric elements (31) is transmitted to the transmission member (10) via a thrust pin (33) whose ends are respectively at contact of the transmission member (10) and said piezoelectric elements (31).   14. Switching device according to claims 11, 12 and 13 characterized 1 o in that the propulsion force (Fp) generated by the piezoelectric actuator is greater than the forces produced respectively by the elastic means (11) and (12).   15. A switching device according to any preceding claim characterized in that the movable contact (2) is directly placed on the disk of the transmission member (10).   16. A hybrid interrupt switch comprising in parallel a mechanical opening means and an electrical opening means, characterized in that the mechanical opening means consists of a switching device according to any one of the claims.