Pyrotechnic switch with a fuse element

Abstract

Pyrotechnic switch (1) including: at least a first circuit portion (10) with two connection terminals (11a, 11b), arranged to be part of an electrical circuit, a mobile body (20), arranged to pass from a first position to a second position, and thereby cause an opening of the first circuit portion (10), a pyrotechnic actuator, arranged to control the movement of the mobile body (20) from the first to the second position, a fuse element (30) such as a fuse, arranged to interrupt an electric current passing between the terminals of the first circuit portion (11a, 11b), characterized in that the fuse element (30) is isolated from at least one of the terminals of the first circuit portion (11a, 11b) when the mobile body (20) is in the first position.

Claims

1. A pyrotechnic switch comprising: at least a first circuit portion with two connection terminals, arranged to be part of an electrical circuit, a mobile body, arranged to pass from a first position to a second position, and thereby cause the first circuit portion to open, a pyrotechnic actuator, arranged to control the movement of the mobile body from the first to the second position, at least one fuse element arranged as part of the pyrotechnic switch, wherein the at least one fuse element is configured to interrupt an electrical current flowing between the connection terminals of the first circuit portion, wherein the at least one fuse element is isolated from at least one of the two connection terminals of the first circuit portion when the mobile body is in the first position, and wherein the mobile body is configured to electrically connect the at least one fuse element with both the two connection terminals as a result of movement of the mobile body between the first position and the second position.

2. The pyrotechnic switch according to claim 1, wherein the first circuit portion is arranged to be sheared when passing from the first position to the second position.

3. The pyrotechnic switch according to claim 1, wherein: in the first position of the mobile body, the first circuit portion includes two conductors in physical contact, the mobile body moves the two conductors away from each other when changing from the first position to the second position.

4. The pyrotechnic switch according to claim 1, wherein the fuse element is arranged to be in electrical contact with the connection terminals, when the mobile body is in the second position.

5. The pyrotechnic switch according to claim 4 wherein the fuse element is in electrical contact with the connection terminals via a conductive element connected to the mobile body, when the mobile body is in the second position.

6. The pyrotechnic switch according to claim 4, wherein the fuse element comprises connection terminals, and wherein: in the first position, at least one of the connection terminals of the fuse element is at a predetermined distance from the first circuit section, in the second position, a conductor from the first circuit portion has at least one open end in physical contact with said at least one connection terminal of the fuse element.

7. The pyrotechnic switch according to claim 1, wherein the switch comprises a second circuit portion electrically connected by the fuse element to a first connection terminal of the first circuit portion when the mobile body is in the first position.

8. The pyrotechnic switch according to claim 7, wherein the second circuit portion is arranged to be connected to the second connection terminal of the first circuit portion when the mobile body is in the second position.

9. The pyrotechnic switch according to claim 1, wherein a conductor from the first circuit portion has at least one open end when the mobile body is in the second position, the open end being arranged at a predetermined distance from a connection terminal of the fuse element, and arranged to define a path of an electric arc between at least one open end of the first circuit portion and at least one connection terminal of the fuse element.

10. The pyrotechnic switch according to claim 9, further comprising a stop piece, wherein the first circuit portion further comprises another open end, and wherein the mobile body is arranged to contact the stop piece when the mobile body is in the second position, to obstruct the path of an electric arc between the at least one open end of the first circuit portion and another open end, so as to force the electric current of the electric arc to pass through the fusible element.

11. The pyrotechnic switch according to claim 9 wherein the mobile body can occupy or pass through a third position between the first position and the second position, wherein: when the mobile body is in the third position, the first circuit portion is cut out to form a separate first upstream, a separate first downstream and a separate first intermediate portion, the Pyrotechnic Switch is arranged to define a path of an electric arc between the first intermediate part and each of the first downstream portion and the first upstream portion.

12. The pyrotechnic switch according to claim 1, wherein the fuse element is installed on the mobile body.

13. A power distribution device comprising the pyrotechnic switch according to claim 1.

14. A motor vehicle comprising at least one pyrotechnic switch according to claim 1.

15. The motor vehicle according to claim 14, wherein the motor vehicle comprises at least one electrical energy storage element, such as a battery or super-capacitors and an electrical propulsion device connected to the electrical power storage element through the at least one pyrotechnic switch.

16. A pyrotechnic switch comprising: at least a first circuit portion with two connection terminals, arranged to be part of an electrical circuit; a mobile body, arranged to pass from a first position to a second position, and thereby cause the first circuit portion to open; a pyrotechnic actuator, arranged to control the movement of the mobile body from the first to the second position; and at least one fuse element arranged to interrupt an electrical current flowing between the connection terminals of the first circuit portion, wherein the at least one fuse element is isolated from at least one of the two connection terminals of the first circuit portion when the mobile body is in the first position, wherein the mobile body is configured to electrically connect the at least one fuse element with at least one of the two connection terminals as a result of movement of the mobile body between the first position and the second position such that when the mobile body is in the second position, an electric arc electrically connects the at least one fuse element with at least one of the two connection terminals.

17. A pyrotechnic switch comprising: at least a first circuit portion with two connection terminals, arranged to be part of an electrical circuit; a mobile body, arranged to pass from a first position to a second position, and thereby cause the first circuit portion to open; a pyrotechnic actuator, arranged to control the movement of the mobile body from the first to the second position; and at least one fuse element arranged to interrupt an electrical current flowing between the connection terminals of the first circuit portion, wherein the at least one fuse element is isolated from at least one of the two connection terminals of the first circuit portion when the mobile body is in the first position, wherein the mobile body is configured to electrically connect the at least one fuse element with at least one of the two connection terminals as a result of movement of the mobile body between the first position and the second position, and wherein the first circuit portion is configured to be sheared when passing from the first position to the second position such that at least one sheared portion electrically couples the at least one fuse element with at least one of the connection terminals.

Description

(1) Other features and benefits of this invention will be seen more clearly from reading of the following detailed description of several embodiments of the invention, provided by way of a non-limiting example and illustrated by the appended drawings, wherein:

(2) FIG. 1 shows a cross-sectional view of a pyrotechnic switch with a fuse element according to a first embodiment of this invention;

(3) FIG. 2 shows a cross-sectional view of a pyrotechnic switch according to a second embodiment of this invention

(4) FIG. 3 shows a cross-sectional view of a switch in a third design mode, wherein a mobile body is in a first position;

(5) FIG. 4 shows a cross-sectional view of the switch in the third mode of execution, wherein the mobile body is in a second position,

(6) FIG. 5 shows a schematic view of a switch in a fourth mode of execution, wherein a mobile body is in the second position.

(7) FIG. 1 shows a cross-sectional view of a pyrotechnic switch 1 with a fuse element, such as a fuse according to this invention. The pyrotechnic switch 1 includes a main body 40 used, among other things, as a housing and a first circuit section 10 made of conductive material, with two connection terminals 11a and 11b, arranged to be part of an electrical circuit. The pyrotechnic switch 1 also includes a mobile body 20 arranged to move from a first position, before tripping, to a second position, after tripping, along a Z axis, and thereby cause the first circuit portion 10 to open. The mobile body 20 is shown in FIG. 1 in the second position, wherein it has physically or mechanically sheared off the first circuit portion 10 into three separate electrical circuit portions, namely a first upstream portion 10a, a first downstream portion 10b and an intermediate portion 10c. The upstream and downstream terms are to be considered according to an electrical direction arbitrarily represented here by the X arrow. For better cutting the first portion 10, the mobile body 20 has a punch shape 21 with a beveled opening and comes to a stop in the second position against a die 25 of the main body 40.

(8) The pyrotechnic switch 1 also includes a pyrotechnic actuator in the form of an electro-pyrotechnic igniter 45 arranged to control a movement of the mobile body 20 from the first to the second position. The electro-pyrotechnical igniter 45 is mounted or overmoulded on the fixing means 44 of the main body 40 of the pyrotechnic switch 1 and communicates with the combustion chamber 43. A pressurized gas from the pyrotechnic actuator is used to move the mobile body 20 from the first position, before tripping, at the bottom of the combustion chamber 43 to the second position, known as the after-trigger position, at the top of the combustion chamber 43 position wherein the mobile body 20 is represented when the pyrotechnic actuator has been triggered. Sealing elements 23 (e. g. an O-ring) mounted on the mobile body 20 complete the sealing of the combustion chamber 43.

(9) In addition, the pyrotechnic switch 1 includes a fuse element 30 arranged to interrupt an electrical current passing between the terminals 11a and 11b of the first circuit portion 10 when the mobile body 20 is in the second position. Fuse element 30 is isolated from the terminals 11a and 11b when the mobile body 20 is in the first position, at the bottom of the combustion chamber 43.

(10) In other words, the first circuit portion 10 is integrated before being cut off by the mobile body 20 and allows the current to pass between its terminals without passing through the fuse element 30, since the boundaries 30a, 30b are distant from the first circuit portion 10. When the mobile body 20 cuts the first portion 10 into three separate circuit portions and that it allows the covering (or physical contact) of the broken or open upstream ends 12a and downstream 12b from a conductor of the first circuit section 10 on the upstream terminals 30a and downstream 30b, respectively, of the fuse element 30, the electrical power can be restored, by passing through the fuse element 30.

(11) The time required to cut off the first circuit portion 10 also known as a busbar, and the folding of broken or open upstream ends 12a and downstream 12b on the upstream terminals 30a and downstream 30b of the fuse element 30 is typically less than 0.1 ms. Sealing means 42, such as O-rings, guarantee the tightness of the switching chamber 46 of the main body 40. An IP67-grade tightness can be achieved, as defined in DIN4050, IEC 60529 or BS 5490. Finally, the fuse element 30 can be overmoulded on the main body 40.

(12) FIG. 2 shows a cross-sectional view of a pyrotechnic switch 100 according to a second method of carrying out this invention. The pyrotechnic switch 100 includes a main body 140 used, among other applications, as housing and a first portion of an electrical circuit 110 with two upstream connection terminals 111a and downstream 111b, respectively, of the upstream portions 110a and downstream 110b, respectively, of the first portion 110 which is arranged to be part of an electrical circuit. The switch 100 also includes a second circuit portion 150 made of conductive material and a fuse element 130 arranged to connect one of the terminals 111a from the first circuit portion to a terminal 150a of the second portion 150.

(13) The pyrotechnic switch 100 also includes a mobile body 120 arranged to pass, respectively, from a first position, before tripping, wherein it is shown in FIG. 2 at a second position, after tripping, and thus cause a contactor 160 to move along a Z axis of a substantially cylindrical shape in a preferred mode of execution. The contactor 160 electrically conductive, allows the upstream portion to be electrically connected 110a to the downstream portion 110b when the mobile body 120 is in the first position. Moving the contactor 160 also takes place from a first position of the contactor 160 to a second position wherein the contactor 160 comes to a stop on the stop 125 of the main body 140.

(14) In other words, when the contactor 160 is in the first position, it electrically connects the terminals 111a and 111b of the first circuit portion 110 without going through the second circuit portion 150 or by the fuse element 130. When the contactor 160 is in the second position, it electrically connects the terminals 111a and 111b of the first portion 110 through the second circuit portion 150 and by the fuse element 130.

(15) In a way comparable to the first embodiment, the mobile body 120 is set in motion on demand by means of a pressurized gas from the pyrotechnic actuator 145 fixed to the main body 140.

(16) FIG. 3 shows a cross-sectional view of a switch 200 according to a third embodiment, wherein a mobile body 220 is in a first position. The pyrotechnic switch 200 includes a main body 240 serving, among other things, as a housing, a first portion of an electrical circuit 210 arranged to be part of an electrical circuit. The switch 200 also includes a cut-off chamber 246 of the main body 240 and fuse element 230 with upstream 30a and downstream 230b terminals, according to an arbitrary electrical direction Y. The mobile body 220 is arranged to move from a first position, known as the pre-trigger position, to a second position, after tripping, along a Z axis, under the effect of an pyrotechnic actuator (not shown). The main body 240 includes a die or stop 225 to stop the movement of the mobile body 220.

(17) FIG. 4 shows a cross-sectional view of the switch 200 according to the third embodiment, wherein the mobile body is in a second position. When the mobile body 220 is set in motion by the pyrotechnic actuator along a Z axis, it cuts the first circuit portion 210 which then has three separate portions: a first downstream portion 210b, a first upstream portion 210a, according to an arbitrary electrical direction Y, and a first intermediate portion 210c, as well as broken or open ends 212a, 212b, 212c and 212d.

(18) When mobile body 220 is in the second position, and if the voltage and/or current are sufficient, as defined for example in the above ranges of use, an electric arc 290a is established between the broken or open end 212a of the first upstream circuit portion 210a and the terminal 230 has a fuse element 230 as well as an electric arc 290b between the broken or open end 212b of the first downstream portion 210b and the terminal 230b of the fuse element 230. The current then flows through the fuse element 230 to protect the circuit.

(19) The electric arc 290a, 290b can also be weakened if its path or passage is forced between the walls covered with ablative material of the mobile body 220 and the switching chamber 246. In this case, the ablative material thus increases the voltage of the electric arc 290a, 290b. This is achieved, for example, by adjusting the dimensions to have a very small operating clearance between the mobile body 220 and the cut-off chamber 246 of the main body 240 with also a groove along the mobile body 220 that guides the electric arc 290a, 290b. It should be noted that the operating clearance may condition the amount of material removed by ablation. The smaller the size of the groove forming the passage, the greater the erosion. Good results are obtained with a groove of 0.1 to 1 mm, and a depth of 0.1 to 1 mm.

(20) When the mobile body 220 is in an intermediate position, also known as the third position, between the first position and the second position, electric arcs can be created between the broken end 212a of the first upstream portion 210a and the broken end 212c of the first intermediate portion 210c, as well as between the broken end 212b of the first downstream portion 210b and the broken end 212d of the first intermediate portion 210c. Depending on the electrical power to be cut off, the current can be cut off from this third position if the reached arc voltage is higher than the voltage at the terminals of the pyrotechnic switch 200. Therefore, the fuse element 230 will not see power flow and will not work.

(21) When the mobile body 220 is in the second position, it is at the stop on the die 225 which obstructs the path of the arcs from the third position and the arcs, if they are still present (e.g, their voltage is lower than the voltage at the terminals of the pyrotechnic switch 200), are forced to move towards the bollards 230a and 230b of the fuse element 230 from the broken ends 212a and 212b of the first portion 210 thanks to a tight fit of the mobile body 220 and the stop 225. This tight fit provides a good seal, which forms a natural barrier against the passage of electrical arcs between the broken ends 212a, 212b, 212c, 212d described in the intermediate position. A negative clearance of 0 to 0.3 mm between the mobile body 220 and the die 225 can be considered at the desired location to cut the path of the electric arcs of the first intermediate portion 210c. The breaking capacity of the fuse element 230 and the electric arcs 290a, 290b are therefore added, achieving a synergy between the fuse element 230 and the pyrotechnic actuator in cooperation with the mobile body 220. Indeed, the third position can be pre-dimensioned to cut off low powers while the fuse element 230 can be sized to cut off high powers. Thus, the fuse element 230 will not have to operate over a very wide range of currents, which are supported by the fuse element, particularly in terms of break times, which are very different.

(22) FIG. 5 shows a schematically represented view of a switch 300 according to a fourth embodiment, wherein a mobile body is in the second position.

(23) The pyrotechnic switch 300 includes a mobile body 320 represented in the second position and a first portion of the electrical circuit 310. When the mobile body 320 moves from the first position to the second position along a Z axis, it cuts the first portion of the electrical circuit 310 which is then divided into separate portions: a first upstream portion 310a, a first downstream portion 310b, downstream and upstream being to be considered in a direction Y that is arbitrarily represented, and a first intermediate portion 310c. The mobile body 320 includes a fuse element 330 with terminals 330a and 330b located upstream and downstream, respectively.

(24) When the mobile body 320 moves from the first to the second position, the terminals 330a and 330b fuse element 330 come into contact with broken or open ends 312a and 312b, respectively, of the first upstream 310a and downstream 310b portions of electrical circuits. The electrical current can now pass through the fuse element 330 when the mobile body 320 is in the second position, when it could not pass through the fuse element 330 when the mobile body 320 in the first position was not engaged with the first portion of the electrical circuit 310.

(25) It will be understood that various modifications and/or improvements, evident to those skilled in the art, can be made to the different embodiments of this invention as described in this description, without going beyond the scope of the invention as defined by the appended claims. In particular, reference is made to the possibility of changing the ablative material, overmolding the fuse element on the main body, or using a mobile body with only one branch instead of two branches in order to reduce the number of broken ends of the first portion of the electrical circuit. Similarly, it is possible to provide a first circuit portion previously broken or cut, the electrical contact being ensured by physical overlapping before the pyrotechnic actuator is triggered and the open end being moved under the action of the mobile body after the pyrotechnic actuator is triggered.