Pyrotechnic circuit breaker

Abstract

A pyrotechnic circuit breaker, comprising at least: - a housing (10), - an electrical conductor (20) to be cut, - a cutting piston (30), movable between a rest position and an activated position, the cutting piston (30) being arranged to cut the electrical conductor (20) during its movement from the rest position to the activated position, - a pyrotechnic actuator (40), housed in the housing (10) and arranged to move the cutting piston (30) from the rest position to the activated position during its operation, characterized in that the circuit breaker comprises at least one deformable element (50), arranged to brake the cutting piston (30) once the electrical conductor (20) is cut, and in that a strictly positive clearance is provided between the deformable element (50) and the electrical conductor (20) before it is cut. 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 a pyrotechnic circuit breaker intended to be mounted, for example, on a motor vehicle. State of the art

[0002] Circuit breaker devices, such as the one described in DE 102022113300 A1, are known in the prior art. These devices propose a deformable piston braking mechanism that evacuates the hot gases generated by arcs during conductor cutting. However, this braking system can have the disadvantage of lengthening the time during which electrical arcs can be established, as the piston speed decreases before the electrical conductor is completely cut, thus increasing the risk of damage to the device. Furthermore, since the piston is subjected during cutting to the resistance of both the conductor and the deformable body, the cutting process is more variable. Description of the invention

[0003] One object of the present invention is to address the disadvantages of the prior art mentioned above and in particular, first of all, to provide a circuit breaker with a high cutting speed so as to reach a maximum arc length as quickly as possible when current passes through the circuit breaker, and / or whose cutting is repeatable, and / or whose housing is less sensitive to a possible shock of the piston at the end of the stroke.

[0004] To this end, a first aspect of the invention relates to a pyrotechnic circuit breaker, comprising at least: - a case, - an electrical conductor to be cut, passing at least partially through the casing, - a cutting piston, housed in the casing and movable between a rest position and an activated position, the cutting piston being arranged to cut the electrical conductor during its movement from the rest position to the activated position, - a pyrotechnic actuator, housed in the casing and arranged to move the cutting piston from the rest position to the activated position during operation, characterized in that the circuit breaker comprises at least one deformable member, arranged to brake the cutting piston once the electrical conductor is interrupted, and in that a strictly positive clearance is provided between the deformable member and the electrical conductor before it is interrupted. According to the above implementation, a clearance is provided between the electrical conductor and the deformable part, so that when the electrical conductor is cut, the deformable part does not undergo any stress: the cut is faster and less variable.

[0005] According to one embodiment, the cutting piston can pass through a contact position during its movement from the rest position to the activated position, wherein the contact position is a position in which the cutting piston is in contact with the electrical conductor before being cut, and wherein a strictly positive clearance is provided between the deformable element and the cutting piston in the contact position. According to the above embodiment, clearance is provided between the deformable element and the cutting piston when the latter begins to contact the electrical conductor to cut it, so that during the cutting of the electrical conductor, the deformable element is not subjected to any stress: the cut is faster and less variable.In other words, a gap may exist between the cutting piston and the deformable part when the cutting piston is in the contact position, so that the cutting piston does not have to bear the resisting force of the deformable part during cutting.

[0006] According to one embodiment, the strictly positive clearance between the deformable member and the cutting piston in the contact position can be a clearance strictly greater than a cutting thickness of the electrical conductor, so that the cutting piston has completely cut the electrical conductor before slowing down by deforming the deformable member.

[0007] According to one embodiment, the cutting piston can be arranged to shear the electrical conductor.

[0008] According to one embodiment, the cutting piston can travel: - a free stroke before cutting the electrical conductor and - a damped stroke during which the deformable element is deformed, for which a ratio of free stroke to damped stroke of the piston can be greater than or equal to 1.2, and preferably greater than 1.5. The free distance can be greater than the damped distance. The applicant has found that the cut is fast and repeatable with such a minimum ratio, while minimizing shocks to the housing.

[0009] According to one embodiment, the piston can travel: - an undamped stroke after cutting the electrical conductor and - a damped stroke during which the deformable part is deformed, and for which a ratio of the undamped stroke to the damped stroke can be greater than or equal to 0.6, and preferably greater than 0.75 and even more preferably greater than 0.85. The applicant found that the cut-off was fast and repeatable with such a minimum ratio, while minimizing shocks on the housing.

[0010] According to one embodiment, the deformable member can be arranged to be deformed directly by the cutting piston. Cutting variability is reduced. with direct contact between the deformable part and the cutting piston: no intermediate component disrupts the operation.

[0011] According to one embodiment, the cutting piston may include at least one contact portion arranged to directly contact the deformable member once the electrical conductor is cut. The cutting piston has a portion dedicated to contact with the deformable member, so that the damping function is repeatable.

[0012] According to one embodiment, the cutting piston may include at least one cutting portion arranged to directly cut the electrical conductor, and said at least one cutting portion may be distinct from said at least one contact portion and / or in which said at least one cutting portion may be offset from said at least one contact portion with respect to the direction of movement of the cutting piston. The cutting piston has a part dedicated to contact with the deformable element, and distinct from the cutting portion, so that the cutting function and the damping function are repeatable.

[0013] According to one embodiment: - the electrical conductor may have a thickness that needs to be cut, - in the rest position, the cutting piston can be positioned at a first distance from the electrical conductor, - in the rest position, the cutting piston can be arranged at a second distance from the deformable part, The second distance can be greater than or equal to the sum of the first distance and the thickness to be cut, and preferably the second distance can be strictly greater than the sum of the first distance and the thickness to be cut. According to this implementation, the cutting piston first contacts the electrical conductor, and then the deformable element.

[0014] According to one embodiment, the cutting piston can be arranged to deform the deformable member irreversibly. The kinetic energy of the cutting piston is absorbed by the irreversible deformation (a plastic deformation, for example).

[0015] According to one embodiment, the deformable member may comprise a main body and at least one damping portion, and the cutting piston may be arranged to deform said at least one damping portion, and preferably only said at least one damping portion. The damping portion is designed to be deformed, so that the braking of the cutting piston is more repeatable.

[0016] According to one embodiment, - the deformable element may comprise at least two damping portions, and preferably an even number of damping portions distributed preferably of symmetrically around the cutting piston, - The cutting piston may comprise at least two contact portions, - and said at least one cutting portion may be arranged between said at least two contact portions. The braking forces are well distributed across the cutting piston, which does not experience overturning or jamming torque: the movement of the cutting piston is more repeatable.

[0017] According to one embodiment, the deformable member can be arranged to absorb heat, so as to cool the inside of the housing possibly heated by arcs caused by the cutting and / or operation of the pyrotechnic actuator.

[0018] According to one embodiment, the deformable element can be a metallic and / or porous, and / or filtering body, in order to withstand the high temperatures generated while being easily deformable.

[0019] According to one embodiment, the deformable element can be a part of the housing, such as a partially overmolded metal insert. The "all-in-one" design reduces manufacturing costs and / or complexity.

[0020] According to one embodiment, the deformable member may include a metal knit and / or a compacted metal wire, in order to dampen the cutting piston.

[0021] According to one embodiment, the housing may include a bearing surface arranged to provide a mechanical stop to the cutting piston and thus define the activated position. The activated position is defined in a robust and reliable manner.

[0022] According to one embodiment, the deformable member can be arranged in the housing.

[0023] According to one embodiment, a second aspect of the invention relates to a motor vehicle, which may include at least one pyrotechnic circuit breaker according to the first aspect of the invention. Description of the figures

[0024] Other features and advantages of the present invention will become more apparent upon reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the accompanying drawings, in which:

[0025] [Fig-1] represents a cross-sectional view of a pyrotechnic circuit breaker before de triggering and including in particular a housing through which an electrical conductor passes, a pyrotechnic actuator, a cutting piston arranged to sever the conductor when the pyrotechnic actuator is activated or triggered and three deformable elements arranged to brake the cutting piston once the conductor has been cut;

[0026] [Fig.2] represents a cross-sectional view of the circuit breaker of [Fig.1] after actuation or triggering of the pyrotechnic actuator;

[0027] [Fig.3] represents an isometric view of the circuit breaker of [Fig.1] before the end of the stroke of the cutting piston and after the cut;

[0028] [Fig.4] represents a cross-sectional view of the circuit breaker of [Fig.1], before activation or triggering of the pyrotechnic actuator, and according to a cutting plane perpendicular to the cutting plane of [Fig.1].

[0029] Detailed description of embodiment(s)

[0030] Figure [1] represents a circuit breaker comprising, in particular: - a housing 10 formed by a lower housing portion 12 and an upper housing portion 11, - an electrical conductor 20 passing through the housing 10, connecting two connection terminals 21 and 22, - a pyrotechnic actuator 40 formed in this example by an electro-pyrotechnic igniter, - 50 deformable parts arranged inside the casing 10, - a cutting piston 30, comprising a body 33 surrounding the pyrotechnic actuator 40 and three projections 31 on the opposite face, separated by grooves 32.

[0031] The housing 10 therefore comprises the lower housing portion 12 and the upper housing portion 11. As shown in [Fig. 1], one or more sealing gaskets can be provided between the lower housing portion 12, the electrical conductor 20 (in particular around an overmolded portion 26 overmolded onto the electrical conductor 20) and the upper housing portion 11. The housing 10 can be formed from plastic material (for example polyamide), with a reinforcing material (glass fibers), and even with metal inserts.

[0032] With regard to the electrical conductor 20, two internal ends 25 define the edges of a portion to be cut 20A of the electrical conductor 20. The electrical conductor 20 is, between the two internal ends 25, in contact on returns of the lower housing 12 forming matrices.

[0033] The cutting piston 30 occupies in [Fig.1] a rest position, opposite the portion to be cut 20A of the electrical conductor 20. More particularly, the three projections 31 are positioned at a predetermined distance a (represented [Fig.4]) from the portion to be cut 20A of the electrical conductor 20.

[0034] Three deformable organs 50 are housed in the lower casing 12, at a predetermined distance b (represented [Fig.4]) from the electrical conductor 20.

[0035] Note [Fig. 1] the presence of a space between the pyrotechnic actuator 40 and the body 33 of the cutting piston 30, which forms a combustion chamber. Furthermore, a space between the cutting piston 30 and the portion to be cut 20A, and a space between the portion to be cut 20A and the deformable elements 50, form a cutting chamber. The combustion and cutting chambers are sealed from each other by a gasket mounted on the cutting piston 30.

[0036] Fig. 2 represents the circuit breaker of Fig. 1 after the electrical conductor 20 has been cut off with the cutting piston 30 in an activated position: under the pressure generated by hot gases produced by the pyrotechnic actuator 40, the cutting piston 30 has moved in the housing 10 towards the bottom of Fig. 2 to occupy the activated position shown.

[0037] During the movement of the cutting piston 30, the electrical conductor 20 was cut into at least four distinct parts (two distinct lateral portions 23 each having an internal end 25 and at least two central portions 24).

[0038] It can be noted [Fig.2] that the cutting piston 30 is in mechanical stop with the overmolded part 26, so that the activated position of the cutting piston of [Fig.2] is precisely defined.

[0039] Fig. 3 shows a partial view of the circuit breaker before the cutting piston 30 arrives in the activated position of Fig. 2, and represents only the cutting piston 30, part of the electrical conductor 20 and the deformable members 50, once the electrical conductor 20 is cut and before deformation of the deformable members 50.

[0040] It can be noted that the three projections 31 of the cutting piston 30 are each composed of a cutting portion 31A intended to cut, shear or slice the electrical conductor 20 and two contact portions 31B, each intended to come into contact with a damping portion 50B of each deformable member 50.

[0041] Each deformable element 50 therefore consists of a main body forming a cooler portion 50A, intended to cool the air in the circuit breaker's breaking chamber, and two damping portions 50B, which are deformable (preferably irreversibly) and adjacent to the cooler portion 50A. The damping portions 50B are offset relative to the cooler portion 50A along the direction of movement of the cutting piston 30, so that the cutting piston 30 comes into contact with the damping portions 50B and not with the cooler portion 50A, upon reaching the activated position of [Fig. 2]. This allows for more precise adjustment of the damping of the cutting piston 30 and thus ensures a sufficient and controlled stroke of the cutting piston 30 after the electrical conductor 20 has been cut, so as to guarantee current interruption.

[0042] The deformable element 50A can be formed as a metallic and / or porous, and / or filtering body, comprising a metal mesh and / or compacted metal wire. Metal wire with a diameter between 0.2 mm and 1.5 mm can be used.

[0043] Figure 4 shows a cross-sectional view of the circuit breaker of Figure 1 passing through the cutting piston 30 and a deformable element 50. Figure 4 therefore represents the circuit breaker before activation, with the cutting piston in its rest position. Note: - the predetermined distance a between the cutting portion 31A of the cutting piston 30 and the portion to be cut 20A of the electrical conductor 20, - the predetermined distance b between the electrical conductor 20 and the cooling portion 50A of the deformable part 50, - a predetermined distance c between the contact portions 31B of the cutting piston 30 and the damping portions 50B of the deformable member 50.

[0044] If e is the thickness of the portion to be cut 20A, we can note that: c > a In other words, the circuit breaker is designed so that the cutting portion 31A comes into contact with the cutting portion 20A before the contact portions 31B come into contact with the damping portions 50B.

[0045] The operation of the circuit breaker will now be explained in detail.

[0046] If the need for a rapid cutting of the electrical conductor 20 is identified, the pyrotechnic actuator 40 is triggered and a high pressure is generated in the combustion chamber (the space between the pyrotechnic actuator 40 and the cutting piston 30), which pushes the cutting piston 30 to move from the rest position shown in [Fig.1], to the activated position in [Fig.2].

[0047] During this movement, the cutting piston 30 first travels a free stroke of predetermined length a (the distance between the projections 31 and the portion to be cut 20A of [Fig.4]), between its rest position and a position of contact with the electrical conductor 20. Once in the contact position, the electrical conductor 20 is cut by the cutting piston 30, for example by mechanical shearing.

[0048] As shown in [Fig. 1], the projections 31 separated by grooves 32 form knives for cutting the section to be cut 20A. During the movement of the cutting piston 30 from the rest position to the activated position, the projections 31 of the cutting piston 30 bear against the unsupported portions of the electrical conductor 20 and shear it at the level of the section to be cut 20A. As shown in [Fig. 2], the shearing of the electrical conductor 20 leads to the formation, after opening, of the two distinct central portions of the electrical conductor 24 (visible in [Fig. 2]) which are separated from the rest of the electrical conductor 20, in particular the distinct lateral portions 23.

[0049] Furthermore, at the very beginning of opening, when the internal ends 25 are still close to the central portions 24, an electric arc can form between each internal end 25 and a central portion 24 if the pyrotechnic circuit breaker is traversed by an electric current. During the movement of the cutting piston 30 from the rest position to the activated position, the cutting piston 30 pushes and causes a bending of each distinct lateral part 23, so that the electric arc travels an arc path which "stretches" or "lengthens" to present at the end of operation a free distance sufficient to guarantee an extinction of the electric arc and a break in the electric current which initially passed through the electric conductor 20.

[0050] After leaving the contact position and beginning the cutting or section of the electrical conductor 20, the cutting piston 30 continues an undamped stroke (equal to cae) before being braked by the damping portions 50B of the deformable member 50 which come into contact with the contact portions 31B of the cutting piston 30. As a result, the damping portions 50B will absorb the kinetic energy of the cutting piston 30 by progressively deforming irreversibly.

[0051] In figures 1, 2 and 4 it can be noted that a positive clearance is left, regardless of the position of the cutting piston 30, between the electrical conductor 20 and the deformable member 50. In particular, it can be noted [Fig.4] that the electrical conductor 20 is distant from the deformable body 50, and when cutting the electrical conductor 20, the two parts do not touch and no additional force beyond the cutting force of the electrical conductor 20 is required.

[0052] The undamped stroke (after cutting) and the clearance between the electrical conductor 20 and the deformable element 50 allow the cutting piston 30 to begin to be slowed down by the deformable element 50 only after the electrical conductor 20 has been completely severed, thus cutting the electrical conductor 20 at high speed and minimizing the "stretching" and "elongation" of the aforementioned arcs. The cutting of the electrical conductor 20 and the breaking of the electrical circuit are therefore rapid and repeatable.

[0053] The cutting piston 30 is therefore mounted in a sliding or translational connection relative to the housing 10 and slides during its movement from the rest position to the activated position, thus providing reproducible and controlled operation and activated position to ensure rapid arc cutting and extinction at the end of operation. However, the arc-cutting stage can generate hot gases that require cooling. For this purpose, the deformable elements have cooling portions 50A (visible in Figures 1 to 4). Thus, the circuit breaker structure can remain simple, with the deformable element performing two functions with distinct parts: - the damping of the cutting piston 30 with the damping portions 50B, - gas cooling, with the 50A cooling portions.

[0054] It can also be noted that the damping portions 50B “surround” the electrical conductor 20, so that the damping forces on the cutting piston 30 are well distributed, which limits the risk of jamming. In other words, the Damping portions 50B are distributed on either side of the electrical conductor 20, and / or the cutting piston 30. Industrial application

[0055] A circuit breaker according to the present invention, and its manufacture, are capable of industrial application.

[0056] It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the different embodiments of the invention described herein without departing from the scope of the invention. In particular, it can be noted that separate components can be provided to ensure cooling and damping. For example, damping portions can be integrated into the housing 10 (with deformable tabs, for example, or an overmolded insert with a portion protruding into the cutoff chamber...).

Claims

Demands

1. Pyrotechnic circuit breaker, comprising at least: - a housing (10), - an electrical conductor (20) to be cut, passing at least partially through the housing (10), - a cutting piston (30), housed in the housing (10) and movable between a rest position and an activated position, the cutting piston (30) being arranged to cut the electrical conductor (20) during its movement from the rest position to the activated position, - a pyrotechnic actuator (40), housed in the housing (10) and arranged to move the cutting piston (30) from the rest position to the activated position during its operation, characterized in that the circuit breaker comprises at least one deformable member (50) separate from the housing (10) and the cutting piston (30), arranged to brake and dampen the cutting piston (30) once the electrical conductor (20) is cut,and in that a strictly positive clearance is provided between the deformable member (50) and the electrical conductor (20) before it is cut, and in that the cutting piston (30) directly contacts said at least one deformable member (50) once the electrical conductor (20) is cut.

2. Pyrotechnic circuit breaker according to claim 1, wherein the cutting piston (30) passes through a contact position during its movement from the rest position to the activated position, wherein the contact position is a position in which the cutting piston (30) is in contact with the electrical conductor (20) before being cut, and wherein a strictly positive clearance is provided between the deformable member (50) and the cutting piston (30) in the contact position.

3. Pyrotechnic circuit breaker according to claim 2, wherein the strictly positive clearance provided between the deformable member (50) and the cutting piston (30) in the contact position is a clearance strictly greater than a thickness (e) to be cut of the electrical conductor (20).

4. Pyrotechnic circuit breaker according to any one of claims 1 to 3 wherein the cutting piston (30) travels: - a free stroke before cutting the electrical conductor (20) and - a damped stroke during which the deformable member (50) is deformed, and in which a ratio of free stroke to damped stroke is greater than or equal to 1.2, and preferably greater than 1.

5.

5. Pyrotechnic circuit breaker according to any one of claims 1 to 4 wherein the cutting piston (30) travels: - an undamped stroke after cutting the electrical conductor (20) and - a damped stroke during which the deformable member (50) is deformed, and wherein a ratio of the undamped stroke to the damped stroke is greater than or equal to 0.6, and preferably greater than 0.75 and even more preferably greater than 0.

85.

6. Pyrotechnic circuit breaker according to any one of claims 1 to 5, wherein the cutting piston (30) includes at least one contact portion (31B) arranged to directly contact the deformable member (50), once the electrical conductor (20) is cut.

7. Pyrotechnic circuit breaker according to claim 6, wherein the cutting piston (30) comprises at least one cutting portion (31 A) arranged to directly cut the electrical conductor (20) and wherein said at least one cutting portion (31 A) is distinct from said at least one contact portion (31 B) and / or wherein said at least one cutting portion (31 A) is offset from said at least one contact portion (31 B) with reference to the direction of movement of the cutting piston (30).

8. Pyrotechnic circuit breaker according to any one of claims 1 to 7, wherein: - the electrical conductor (20) has a thickness (e) to be cut, - in the rest position, the cutting piston (30) is arranged at a first distance from the electrical conductor (20), - in the rest position, the cutting piston (30) is arranged at a second distance from the deformable member (50), and wherein the second distance is greater than or equal to the sum of the first distance and the thickness (e) to be cut, and preferably the second distance is strictly greater than the sum of the first distance and the thickness (e) to be cut.

9. Pyrotechnic circuit breaker according to any one of claims 1 to 8, wherein the cutting piston (30) is arranged to deform the deformable member (50) irreversibly.

10. Pyrotechnic circuit breaker according to any one of claims 1 to 9, in wherein the deformable member (50) comprises a main body and at least one damping portion (50B), and in which the cutting piston (30) is arranged to deform said at least one damping portion (50B), and preferably only said at least one damping portion (50B).

11. Pyrotechnic circuit breaker according to claim 10 in its dependence on claim 8, - wherein the deformable member (50) comprises at least two damping portions (50B), and preferably an even number of damping portions (50B) distributed preferably symmetrically around the cutting piston (30), - wherein the cutting piston (30) comprises at least two contact portions (31B), - and wherein said at least one cutting portion (31A) is arranged between said at least two contact portions (31B).

12. Pyrotechnic circuit breaker according to any one of claims 1 to 11, wherein the deformable member (50) is arranged to absorb heat.

13. Pyrotechnic circuit breaker according to any one of claims 1 to 12, wherein the deformable member (50) is a metallic and / or porous, and / or filtering body.

14. Pyrotechnic circuit breaker according to any one of claims 1 to 13, wherein the deformable member (50) is a part of the housing (10), such as for example a partially overmolded metal insert.

15. Pyrotechnic circuit breaker according to any one of claims 1 to 14, wherein the deformable member (50) comprises a metal knit and / or a compacted metal wire.

16. Pyrotechnic circuit breaker according to any one of claims 1 to 15, wherein the housing (10) includes a bearing surface arranged to provide a mechanical stop to the cutting piston (30) and thus define the activated position.

17. Pyrotechnic circuit breaker according to any one of claims 1 to 16, wherein the deformable member (50) is arranged in the housing (10).

18. Motor vehicle, comprising at least one pyrotechnic circuit breaker according to any one of claims 1 to 17.

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