Pyrotechnic circuit breaker

Abstract

A pyrotechnic circuit breaker comprising: - a housing (10), - an electrical conductor (20), - a cutting piston (30), movable and arranged to cut the electrical conductor (20) when transitioning from the rest position to the activated position, - at least one die (40), arranged to support at least a portion of the electrical conductor (20) during at least part of the cutting of the electrical conductor (20) by the cutting piston (30), - at least one pyrotechnic actuator (50), arranged to move the cutting piston (30) from the rest position to the activated position, characterized in that the die (40) comprises a recessed cavity (43) designed to impose plastic deformation on said at least a supported portion of the electrical conductor (20) during the cutting of the electrical conductor (20) by the cutting piston (30). Figure for the abbreviation: Fig. 1

Description

Title of the invention: Pyrotechnic circuit breaker Technical field of the invention

[0001] The present invention relates generally to circuit breakers mounted in motor vehicles for cutting an electrical circuit in the event of an emergency situation. Typically used for electric or hybrid vehicles, the circuit breakers according to the invention can be used to cut a power and / or supply circuit of the traction chain. Such electrical circuits can have electrical voltages of several hundred or thousands of volts, and / or be traversed by currents of several hundred or thousands of amperes. State of the art

[0002] It is known in the prior art of circuit breakers to cut an electrical conductor, and as shown in document FR3017240A1, provision may be made to form a free strand of electrical conductor, completely separated from the rest of the initial electrical conductor after the circuit has been cut. On the other hand, this system may present variability if the free strand of electrical conductor is caused to move in the circuit breaker and cause an alteration of the expected operation, in particular if it comes to obstruct the movement of the cutting piston, etc.). However, the generation of a free strand of electrical conductor may be desirable to increase the voltage generated by the circuit breaker during the cutting operation, because two electric arcs may form on either side of the free strand of electrical conductor, which increases the voltage across the terminals of the circuit breaker and promotes rapid cutting of the flow of electric current.Furthermore, the cutting piston, at the end of its stroke, must be decelerated to be immobilized in an activated position (or a cutting position) which must be maintained and repeatable (for example to form a closed internal chamber in the circuit breaker). Stopping in this activated position can be difficult to guarantee due to the high movement speeds and the shocks with the housing and / or rebounds which can result. Statement of the invention

[0003] An object of the present invention is to address the drawbacks of the prior art mentioned above and in particular, first of all, to propose a circuit breaker arranged to cut an electrical circuit in a more reproducible and more reliable manner. In particular, an object of the present invention may be to propose a circuit breaker arranged to cut an electrical circuit in a more reproducible and more reliable manner even if it is intended to form a free strand of electrical conductor. In particular, an object of the present invention may be to propose a circuit breaker arranged to cut an electrical circuit whose activated position of the cutting piston is guaranteed in a more reproducible and reliable manner.

[0004] For this purpose, a first aspect of the invention relates to a pyrotechnic circuit breaker comprising: - a case, - an electrical conductor passing at least partially through the housing, - a cutting piston, housed in the housing, movable between a rest position and an activated position, and arranged to cut the electrical conductor when moving from the rest position to the activated position, - at least one die, arranged in the housing to support at least a portion of the electrical conductor during at least part of the cutting of the electrical conductor by the cutting piston, - at least one pyrotechnic actuator, housed in the housing, and arranged to move the cutting piston from the rest position to the activated position, characterized in that the die comprises a hollow imprint provided to impose a plastic deformation on said at least one supported portion of the electrical conductor during cutting of the electrical conductor by the cutting piston. According to this implementation, at least a portion of the electrical conductor is deformed irreversibly or plastically, so that: - the position is better controlled because the overall size of the electrical conductor is increased, the electrical conductor has less possibility of moving without interfering with the rest of the circuit breaker, and / or - the cutting piston imposes the plastic or irreversible deformation, so that it transfers energy to the electrical conductor, which makes it possible to dampen or slow down the cutting piston moving towards the activated position, and / or - the deformed portion of the electrical conductor can then serve as a shock absorber for the cutting piston when it reaches the activated position.

[0005] The invention can then be defined with the following characteristics, taken individually or in combination.

[0006] According to one embodiment, the plastic deformation imposed on the electrical conductor imposes an irreversible deformation or an irreversible displacement or an irreversible bending of the electrical conductor in a direction parallel or aligned with a direction of movement of the cutting piston. In other words, the electrical conductor has a deformed zone which has been displaced in the direction of movement of the cutting piston. The electrical conductor with such irreversible deformation can of course be deformed again plastically (or to a lesser extent elastically) subsequently.

[0007] According to one embodiment, preferably once the conductor has been cut electrically performed, at least one deformed area of ​​the electrical conductor is arranged to form a braking obstacle to the cutting piston as it moves to the activated position. The deformed area of ​​the electrical conductor forms a retarder or shock absorber for the cutting piston to allow it to stop gradually in the activated position, which is then more reproducible. Bouncing or shocks on the housing are eliminated or at least attenuated.

[0008] According to one embodiment, the electrical conductor has a conductor axial direction, and wherein the recessed imprint has an imprint axial direction substantially aligned with the conductor axial direction. The recessed imprint may be a groove aligned with an axial direction of the electrical conductor.

[0009] According to one embodiment, the die has a support surface arranged opposite and / or in parallel with the electrical conductor, and the hollow imprint forms a step in the support surface in a direction opposite the electrical conductor, before cutting. Such a step causes a collapse or a sagging of the electrical conductor when it is sheared by the cutting piston, leading to a plastic and / or irreversible deformation.

[0010] According to one embodiment, the cutting piston has at least two cutting blades so as to form a free strand of electrical conductor when cutting the electrical conductor, and the free strand of electrical conductor comprises or forms said at least one portion of the electrical conductor supported by the die. Consequently, the free strand of electrical conductor will be plastically deformed when the cutting piston moves: the imprint causes a support defect between the die and the electrical conductor which leads to a bending of the free strand of electrical conductor.

[0011] According to one embodiment, a distance separating said at least two cutting blades (in particular in a direction transverse to a direction of movement of the cutting piston) is less than an overall dimension of the free strand of plastically deformed electrical conductor (in particular in a direction of movement of the cutting piston). Thus, the free strand cannot turn back on itself between the cutting blades: it abuts on the sides of the cutting blades.

[0012] According to one embodiment, in the activated position, the cutting piston and the die form a closed enclosure around the free strand of electrical conductor.

[0013] According to one embodiment, in the activated position, the cutting piston and the die are separated by a space having, in a direction of movement of the cutting piston, a dimension less than a length or a width of the free strand of electrical conductor. Consequently, this makes it possible to limit the risk of the free strand of electrical conductor turning over, which could form an obstacle. placing the cutting piston towards the activated position. The plastic deformation imposed on the free strand of electrical conductor increases its size and makes such a reversal more difficult or even impossible.

[0014] According to one embodiment, the plastic deformation imposed on the electrical conductor comprises or consists at least of a fold along a fold line.

[0015] According to one embodiment, the fold line is parallel or aligned with an axial direction of the electrical conductor, the axial direction being defined before cutting the electrical conductor.

[0016] According to one embodiment, the cutting piston has at least one progressive or inclined cutting edge, so as to complete the cutting of the electrical conductor in an area opposite or adjacent to the hollow impression. Thus, when the cutting occurs opposite the impression, the remainder of the electrical conductor is detached and can move under the effect of plastic deformation.

[0017] According to one embodiment, the hollow imprint is arranged opposite an area arranged in the middle of the electrical conductor. The cutting forces are balanced on each side of the electrical conductor.

[0018] According to one embodiment, the deformation of the electrical conductor imposes a V-shape on the electrical conductor. Such a V-shape has a size (depending on the direction of movement of the cutting piston) which makes any turning or pivoting of the electrical conductor (typically the free strand of electrical conductor) difficult.

[0019] According to one embodiment, the electrical conductor has a thickness to be cut, and the hollow imprint has a depth of at least 50%, preferably at least 80%, of the thickness to be cut. According to one embodiment, the hollow imprint has a depth of at least 0.25 mm, preferably at least 0.5 mm, preferably at least 0.8 mm, preferably at least 1 mm, preferably at least 1.25 mm, preferably at least 1.5 mm.

[0020] According to one embodiment, the electrical conductor has a width to be cut, and the hollow imprint has a width of at least 30%, preferably at least 40%, of the width to be cut. According to one embodiment, the hollow imprint has a width of at least 5 mm, preferably at least 7.5 mm, preferably at least 10 mm, preferably at least 12.5 mm, preferably at least 155 mm. Description of figures

[0021] Other characteristics and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the drawings. annexed, in which:

[0022] [Fig.l] represents a sectional view of a circuit breaker according to the invention comprising a housing, an electrical conductor and a cutting piston, the cutting piston occupying a rest position and the section of [Fig.l] being made along a sectional plane comprising an axis parallel to a direction of movement of the cutting piston and an axis parallel to a longitudinal direction of the electrical conductor;

[0023] [Fig.2] represents a sectional view of the circuit breaker of [Fig.l], in a sectional plane comprising an axis parallel to the direction of movement of the cutting piston and an axis transverse to a longitudinal direction of the electrical conductor, the cutting piston occupying the rest position;

[0024] [Fig.3] represents the sectional view of the circuit breaker of [Fig.2], the cutting piston having left the rest position and occupying an intermediate cutting position;

[0025] [Fig.4] represents the sectional view of the circuit breaker of [Fig.2], the cutting piston occupying a final cutting position called the activated position.

[0026] Detailed description of embodiment(s)

[0027] [Fig.l] represents a pyrotechnic circuit breaker comprising: - a housing 10 formed by an upper housing 11 and a lower housing 12, - an electrical conductor 20 passing at least partially through the housing 10, - a cutting piston 30, housed in the housing 10, movable between a rest position (occupied position [Fig.l]) and an activated position (occupied position [Fig.4]), and arranged to cut the electrical conductor 20 when moving from the rest position to the activated position, - at least one die 40, arranged in the housing 10 to support at least a portion of the electrical conductor 20 during at least part of the cutting of the electrical conductor by the cutting piston, - at least one pyrotechnic actuator 50, housed in the housing 10, and arranged to move the cutting piston 30 from the rest position to the activated position.

[0028] It may be noted that the section of [Fig.l] is made along a section plane comprising an axis parallel to a direction of movement of the cutting piston 30 and an axis parallel to a longitudinal direction of the electrical conductor 20.

[0029] In detail and with regard to the housing 10, the upper housing 11 comprises an internal bore which receives the cutting piston 30 in sliding connection. The internal bore is closed by an igniter support 13 which receives the pyrotechnic actuator, here an electro-pyrotechnic igniter comprising in particular a loading case 51 and connection pins 52.

[0030] The lower housing 12 comprises housings receiving coolers 60, and the body of the lower housing 12 forms dies 40 with in particular a first die 41, a second die 42 each supporting a portion of the electrical conductor 20 (it being understood that the electrical conductor 20 is supported by the internal side walls of the lower housing 12 which also form matrices), the second matrix 42 specifically comprising a recessed impression 43.

[0031] The housing 10 also comprises a frame 13 overmolded on the electrical conductor 20 to be able to position the electrical conductor 20 easily in the housing 10, with a sandwiching of the frame 13 between the upper housing 11 and the lower housing 12.

[0032] The frame 13 may be formed from a plastic material, for example a polymer, the upper housing 11 may be formed from a plastic material, for example a polymer and may include an internal (as shown) or external metal insert, and the lower housing 12 may be formed from a plastic material, for example a polymer and may also include an internal or external metal insert.

[0033] The electrical conductor 20 is therefore supported by the frame 13 and comprises: - two connection ends 21 external to the housing 10, - a first internal portion 23 supported by the first matrix 41, - a second internal portion 24 supported by the second matrix 42, - section reductions 22 arranged between the various aforementioned portions, in order to assist in cutting or folding the electrical conductor 20. In the configuration of [Fig.l] with the cutting piston in the rest position, the electrical conductor 20 is continuous, in one piece with all the portions still connected together.

[0034] The cutting piston 30 is housed in the housing 10 and essentially defined: - a combustion chamber 14 arranged between the cutting piston 30 and the pyrotechnic actuator 50, - a cutting chamber 15 arranged between the cutting piston 30 and the electrical conductor 20 and / or the dies 40.

[0035] More specifically, the cutting piston 30 comprises in particular: - a first cutting blade 31 arranged in the cutting chamber 15, - a second cutting blade 32 arranged in the cutting chamber 15, - a third cutting blade 33 arranged in the cutting chamber 15, - a bearing surface 37 arranged between the second cutting blade 32 and the third cutting blade 33, - a cylindrical body 34, received in the bore of the upper housing 11, - an O-ring 36, supported by the cylindrical body 34, - a well 35 formed in the cylindrical body to define the combustion chamber 14. Accordingly, it can be noted that the electrical conductor 20 will be cut in three separate locations by the first cutting blade 31, the second cutting blade 32, and the third cutting blade 33. Two free strands of electrical conductor will be formed, essentially from the first internal portion 23 and the second internal portion 24.

[0036] [Fig.2] represents a sectional view of the circuit breaker of [Fig.l], in a sectional plane comprising an axis II-II of [Fig.l] parallel to the direction of movement of the cutting piston 30 and comprising an axis transverse to a longitudinal direction of the electrical conductor 20, the cutting piston 30 always occupying the rest position.

[0037] The following points can be noted [Fig.2]: - the axis II-II of [Fig.l], parallel to the direction of movement of the cutting piston 30, passes through the second internal portion 24 of the electrical conductor 20, supported by the second die 42, - the second die 42 therefore comprises a hollow imprint 43 arranged under the second internal portion 24 opposite the cutting piston 30, so that the support provided by the second die 42 to the second internal portion 24 is partial, - the third cutting blade 33 of the cutting piston 30 is beveled and has a profile inclined relative to the second internal portion 24.

[0038] The hollow imprint 43 presents in this example: - a width of approximately half the width of the second internal portion 24 supported by the second matrix 42, - a depth in the second matrix 42 approximately equivalent to the thickness of the second internal portion 24 supported by the second matrix 42, - a central position relative to the second internal portion 24 supported by the second matrix 42.

[0039] The third cutting blade 33 of the cutting piston 30 is beveled in an inverted V shape relative to the second internal portion 24 supported by the second die 42, at an angle of approximately 5° to 10° in this example, and / or over a height approximately equivalent to the thickness or half the thickness of the second internal portion 24 supported by the second die 42. Provision may be made for at least the second cutting blade 32 (and / or the first cutting blade 31) to have the same profile as the third cutting blade 33.

[0040] Consequently, during the descent of the cutting piston 30 from the rest position, the electrical conductor 20 (and in particular the second internal portion 24) will be progressively cut by the second cutting blade 32 and the third cutting blade 33. The cutting will begin with the edges of the second internal portion 24 and will end in the center, precisely where the hollow imprint 43 is located. The second internal portion 24 not being supported at the hollow imprint 43 and having its edges already cut, a plastic deformation will be imposed on the electrical conductor 20 and in particular on the second internal portion 24 during the cutting.

[0041] Indeed, [Fig.3] represents the sectional view of the circuit breaker of [Fig.2], the piston cutting piston 30 having left the rest position of figures 1 and 2 and occupying an intermediate cutting position. The third cutting blade 33 is shown in dotted lines because it has passed behind the second die 42 and the second internal portion 24. It can be noted that the position of the cutting piston 30 is that in which the third cutting blade 33 is just finishing cutting the second internal portion 24. Consequently, all the cutting force is concentrated on the middle of the second internal portion 24 which is no longer supported only by the hollow impression 43. The central cutting force therefore imposes a collapse, a sagging or a movement of the central part of the second internal portion 24 in the hollow impression 43 and a plastic deformation of the second internal portion 24 due to the edges of the second internal portion 24 resting on the sides of the hollow impression 43.The plastic deformation causes a V-shaped deformation of the second internal portion 24. .

[0042] Considering [Fig. 1], it can be noted that the second internal portion 24 now separated from the rest of the electrical conductor 20 is arranged between the second cutting blade 32 and the third cutting blade 33. Indeed, at this stage of the movement of the cutting piston 30 of [Fig. 3], the second cutting blade 32 and the third cutting blade 33 surround the second internal portion 24 and the second die 42.

[0043] The second cutting blade 32 and the third cutting blade 33 therefore gradually approach the second die 42 and their sides will contact each other to form a closed space. The V-shaped deformation imposed on the second internal portion 24, visible [Fig. 3], significantly increases its size in the direction of movement of the cutting piston 30. The second internal portion 24 forming at this stage a free strand could turn over in the housing between the second cutting blade 32 and the third cutting blade 33 but the imposed V-shaped deformation considerably limits the risk of such a turnover.

[0044] Indeed, such a reversal around an axis normal to the plane of [Fig.l] or horizontal in [Fig.3] is limited or prohibited because the edges of the V increase the overall size of the second internal portion 24 forming a free strand and can come to bear on the sides of the second cutting blade 32 or of the third cutting blade 33. The position of the second internal portion 24 forming a free strand is better controlled during operation.

[0045] [Fig.4] represents the sectional view of the circuit breaker of [Fig.2], the cutting piston 30 occupying a final cutting position called the activated position, in which the electrical conductor 20 is completely cut and the cutting piston 30 is at the end of its stroke.

[0046] It can be noted that the bearing surface 37 has come into contact with the second internal portion 24 which has been deformed again by the cutting piston 30 for return to a flat shape. Thus, the cutting piston 30 has been cushioned or braked by the second internal portion 24 before reaching the activated position. Such deformation imposed by the obstacle formed by the second internal portion 24 has therefore braked / cushioned the cutting piston so as to limit shocks between the housing 10 or rebounds or backward movement of the cutting piston 30. The final activated position and / or the robustness of operation is better guaranteed with the second internal portion 24 deformed initially and redeformed subsequently. Industrial application

[0047] A circuit breaker according to the present invention, and its manufacture, are capable of industrial application.

[0048] It will be understood that various modifications and / or improvements obvious to those skilled in the art may be made to the various embodiments of the invention described in the present description without departing from the scope of the invention. In particular, provision may be made to cut the electrical conductor into fewer or more parts or positions. The hollow imprint may be of different shapes, or several hollow imprints may be provided at several locations.

Claims

Claims

1. Pyrotechnic circuit breaker comprising: - a housing (10), - an electrical conductor (20) passing at least partially through the housing (10), - a cutting piston (30), housed in the housing (10), movable between a rest position and an activated position, and arranged to cut the electrical conductor (20) when moving from the rest position to the activated position, - at least one die (40), arranged in the housing (10) to support at least a portion of the electrical conductor (20) during at least part of the cutting of the electrical conductor (20) by the cutting piston (30), - at least one pyrotechnic actuator (50), housed in the housing (10), and arranged to move the cutting piston (30) from the rest position to the activated position,characterized in that the die (40) comprises a hollow imprint (43) provided to impose a plastic deformation on said at least one supported portion of the electrical conductor (20) during the cutting of the electrical conductor (20) by the cutting piston (30).,

2. A pyrotechnic circuit breaker according to claim 1, wherein at least one deformed area of ​​the electrical conductor (20) is arranged to form a braking obstacle to the cutting piston (30) when it moves to the activated position.

3. A pyrotechnic circuit breaker according to claim 1 or 2, wherein the electrical conductor (20) has a conductor axial direction, and wherein the recessed imprint (43) has an imprint axial direction substantially aligned with the conductor axial direction.

4. Pyrotechnic circuit breaker according to one of claims 1 to 3, in which the matrix (40) has a support surface arranged opposite and / or in parallel with the electrical conductor (20), and in which the hollow imprint (43) forms a recess in the support surface in a direction opposite the electrical conductor (20), before cutting.

5. Pyrotechnic circuit breaker according to one of claims 1 to 4, in which the cutting piston (30) has at least two cutting blades (31, 32, 33) so as to form a free strand of electrical conductor (20) when cutting the electrical conductor (20), and wherein the free strand of electrical conductor (20) comprises or forms said at least one portion of the electrical conductor (20) supported by the die (40).

6. Pyrotechnic circuit breaker according to claim 5, in which, in the activated position, the cutting piston (30) and the die (40) form a closed enclosure around the free strand of electrical conductor (20).

7. Pyrotechnic circuit breaker according to one of claims 1 to 6, in which the plastic deformation imposed on the electrical conductor (20) comprises or consists at least of a fold along a fold line.

8. A pyrotechnic circuit breaker according to claim 7, wherein the fold line is parallel or aligned with an axial direction of the electrical conductor (20), the axial direction being defined before cutting the electrical conductor (20).

9. Pyrotechnic circuit breaker according to one of claims 1 to 8, in which the cutting piston (30) has at least one progressive or inclined cutting edge, so as to complete the cutting of the electrical conductor (20) in an area opposite or adjacent to the hollow imprint (43).

10. Pyrotechnic circuit breaker according to one of claims 1 to 9, in which the hollow imprint (43) is arranged opposite an area arranged in the middle of the electrical conductor (20).

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