Electric circuit breaker device

Abstract

To provide an electric circuit breaker device that can be downsized while maintaining strength. An igniter 20, a bar-shaped projectile 40, a conductor piece 50, and an insulating space 61 are provided inside a resin housing 10. A cylinder 30 is disposed between the bar-shaped projectile 40 and an inner wall surface of the housing 10, and further, a reinforcing frame 70 is disposed in the housing 10 on the outer side. A discharge path for combustion products generated by actuation of the igniter 20 is provided between the insulating space 61 and a second end 12 of the housing.

Claims

1. An electric circuit breaker device, comprising: a housing made of a synthetic resin; an igniter; a bar-shaped projectile made of a synthetic resin; a conductor piece forming a part of an electric circuit, the igniter, the bar-shaped projectile, and the conductor being disposed in this order from a first end side of the housing to an axially opposite second end side of the housing; and an insulating space formed between the second end of the housing and the conductor piece, the conductor piece being a plate piece comprising a first connection portion and a second connection portion at opposite ends and an intermediate cutting portion, with a surface of the cutting portion being disposed orthogonal to the axial direction of the housing, the bar-shaped projectile being disposed to oppose the surface of the cutting portion of the conductor piece in the axial direction of the housing, a cylinder being disposed between the bar-shaped projectile and an inner wall surface of the housing, and a discharge path for combustion products generated by actuation of the igniter being provided between the insulating space and the second end of the housing, wherein the cutting portion of the conductor piece has a fragile portion in at least one of a first surface on the first end side and a second surface on the second end side.

2. The electric circuit breaker device according to claim 1, wherein the cylinder is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

3. An electric circuit breaker device, comprising: a housing made of a synthetic resin; an igniter; a bar-shaped projectile made of a synthetic resin; a conductor piece to form a part of an electric circuit, the igniter, the bar-shaped projectile, and the conductor piece being disposed in this order from a first end side of the housing to an axially opposite second end side of the housing; and an insulating space formed between the second end of the housing and the conductor piece, the conductor piece being a plate piece comprising a first connection portion and a second connection portion at opposite ends and an intermediate cutting portion, with a surface of the cutting portion being disposed orthogonal to the axial direction of the housing, the bar-shaped projectile being disposed to oppose the surface of the cutting portion of the conductor piece in the axial direction of the housing, a cylinder being disposed between the bar-shaped projectile and an inner wall surface of the housing, a reinforcing frame, provided separately from the conductor piece, and being further disposed within the housing outside of the cylinder and the insulating space, and a discharge path for combustion products generated by actuation of the igniter being provided between the insulating space and the second end of the housing.

4. The electric circuit breaker device according to claim 3, wherein: the reinforcing frame is U-shaped or similarly shaped in plan, and has a base plate including a gas passage hole penetrating in a thickness direction, and a first side plate and a second side plate extending in the same direction from lengthwise opposite ends of the base plate; the reinforcing frame is disposed to outwardly surround the insulating space and the cylinder with spacing, such that the base plate is in the second end side of the housing, and a tip end of the first side plate and a tip end of the second side plate are in the first end side of the housing; and the gas passage hole of the base plate forms a part of the discharge path for combustion products.

5. The electric circuit breaker device according to claim 3, wherein: the reinforcing frame is U-shaped or similarly shaped in plan, and has a base plate including a gas passage hole penetrating in a thickness direction, and a first side plate and a second side plate extending in the same direction from lengthwise opposite ends of the base plate; the first side plate is narrowed between the base plate and the tip end to have a first recess, and the second side plate is narrowed between the base plate and the tip end to have a second recess, the first recess and the second recess being formed at opposing positions; the reinforcing frame is disposed to outwardly surround the insulating space and the cylinder with spacing, such that the base plate is in the second end side of the housing, a tip end of the first side plate and a tip end of the second side plate are in the first end side of the housing, and further, the first connection portion and the second connection portion of the conductor piece extend across the first recess and the second recess; and the gas passage hole of the base plate forms a part of the discharge path for combustion products.

6. The electric circuit breaker device according to claim 3, wherein the reinforcing frame has a hole penetrating in the thickness direction in a part of the first side plate excluding the first recess, and in a part of the second side plate excluding the second recess.

7. The electric circuit breaker device according to claim 3, wherein the reinforcing frame is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

8. The electric circuit breaker device according to claim 3, wherein the cylinder is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

9. The electric circuit breaker device according to claim 3, wherein the cutting portion of the conductor piece has a fragile portion in at least one of a first surface on the first end side and a second surface on the second end side.

10. The electric circuit breaker device according to claim 4, wherein the reinforcing frame has a hole penetrating in the thickness direction in a part of the first side plate excluding the first recess, and in a part of the second side plate excluding the second recess.

11. The electric circuit breaker device according to claim 5, wherein the reinforcing frame has a hole penetrating in the thickness direction in a part of the first side plate excluding the first recess, and in a part of the second side plate excluding the second recess.

12. The electric circuit breaker device according to claim 4, wherein the reinforcing frame is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

13. The electric circuit breaker device according to claim 5, wherein the reinforcing frame is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

14. The electric circuit breaker device according to claim 6, wherein the reinforcing frame is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

15. The electric circuit breaker device according to claim 4, wherein the cylinder is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

16. The electric circuit breaker device according to claim 5, wherein the cylinder is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

17. The electric circuit breaker device according to claim 6, wherein the cylinder is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

18. The electric circuit breaker device according to claim 7, wherein the cylinder is selected from those made of stainless steel, aluminum, and a carbon-fiber reinforced resin.

19. An electric circuit breaker device, comprising: a housing made of a synthetic resin; an igniter; a bar-shaped projectile made of a synthetic resin; and a conductor piece forming a part of an electric circuit, the igniter, the bar-shaped projectile, and the conductor being disposed in this order from a first end side of the housing to an axially opposite second end side of the housing, an insulating space being formed between the second end of the housing and the conductor piece, the conductor piece being a plate piece comprising a first connection portion and a second connection portion at opposite ends and an intermediate cutting portion, with a surface of the cutting portion being disposed orthogonal to the axial direction of the housing, the bar-shaped projectile being disposed to oppose the surface of the cutting portion of the conductor piece in the axial direction of the housing, a cylinder being disposed between the bar-shaped projectile and an inner wall surface of the housing, and a discharge path for combustion products generated by actuation of the igniter being provided between the insulating space and the second end of the housing, wherein the cutting portion of the conductor piece has a first fragile portion in a first surface on the first end side, and a second fragile portion in a second surface on the second end side; and of the first surface having the first fragile portion and the second surface having the second fragile portion, the second surface has a smaller strength.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is an axial section of an electric circuit breaker device of the present invention.

(2) FIG. 2 Parts (a) and (b) of FIG. 2 are partial enlargements of FIG. 1.

(3) FIG. 3 is a perspective view of a reinforcing frame.

(4) FIG. 4 is an axial section of the electric circuit breaker device of FIG. 1 after actuation.

EMBODIMENTS OF THE INVENTION

(5) An embodiment of an electric circuit breaker device 1 of the present invention will be described with reference to FIGS. 1 and 2. A housing (resin housing) 10 made of a synthetic resin has a cylindrical space 13 that penetrates from a first end 11 to a second end 12. A connector fitting portion 15 that is connected with a power source by a lead wire during use is attached on the first end 11 side.

(6) An igniter 20, a projectile 40 made of a synthetic resin, and a conductor piece 50 are disposed in this order in the axial direction from the first end 11 side, in a cylindrical space 13 of the housing 10. The igniter 20 has an ignition portion 21, and a resin portion 22 in which the igniter itself having a conductive pin 23 is partially surrounded by a resin, the ignition portion 21 protruding from the resin portion 22.

(7) The projectile 40 shown in FIG. 1 may adopt the same configuration as that shown in FIG. 1 and part (a) of FIG. 2 of JP-A 2016-85947. The projectile 40 has a rod 41, and a tip end enlarged-diameter portion 42 formed on the tip of the rod 41. The outer diameter of the tip end enlarged-diameter portion 42 is larger than the outer diameter of the rod 41.

(8) The sectional shape in the width direction (direction that crosses the axial direction) of the rod 41 is a circle, and the sectional shape in the width direction of the tip end enlarged-diameter portion 42 is a quadrangle (preferably a square) or a circle, and is more preferably a square.

(9) The rod 41 has a neck portion 43 where the outer diameter is partially reduced, and an O-ring 44 made of rubber (e.g., silicon rubber) or a synthetic resin is fitted into the neck portion 43. Compared to the outer diameter of the rod 41, the outer diameter of the part where the O-ring 44 is fitted is slightly larger.

(10) Note that the neck portion 43 and the O-ring 44 may be omitted from the present invention to more easily ensure a discharge path for combustion products at the time of actuation. Instead, a neck portion may be formed in an end surface 42b of the rod 41 facing the igniter 20 and an O-ring may be fitted thereinto, so that the O-ring may drop more easily at the time of actuation, and a discharge path for combustion products may be ensured more easily. An axially continuous groove as a vent hole may be formed between the rod 41 and the tip end enlarged-diameter portion 42. One groove, or two or more grooves may be formed.

(11) The cylinder 30 shown in FIG. 1 is provided to reinforce the housing 10, and is made of metal such as stainless steel and aluminum, or fiber reinforced resin such as carbon-fiber reinforced resin.

(12) Although the thickness of the cylinder 30 varies depending on the size of device 1, the range is preferably about 0.5 to 3 mm. An outer surface 30a of the cylinder 30 is brought into contact with an inner wall surface 13a of a cylindrical space 13. Of the cylinder 30, a first end opening 31 side abuts on the resin portion 22 of the igniter 20, while a second end opening 32 side on the opposite side abuts on an annular stepped face 45 (part (a) of FIG. 2) of the projectile 40.

(13) The cylinder 30 surrounds the ignition portion 21 of the igniter 20 and the rod 41 of the projectile 40. At this time, the O-ring 44 fitted into the neck portion 43 of the projectile 40 is in contact with an inner circumferential surface 30b of the cylinder 30, but an outer surface of the rod 41 and the inner circumferential surface 30b of the cylinder 30 are not in contact with each other. The cylinder 30 is press-fitted into the cylindrical space 13 to be fixed and restricted from moving in the axial direction.

(14) Note that the cylinder 30 may be fixed and restricted from moving in the axial direction by forming a claw portion in the outer surface 30a of the cylinder 30, forming a recess corresponding to the claw portion in a radially opposite inner wall surface (an inner wall surface 13a of the cylindrical space 13) of the housing 10, and fitting the claw portion into the recess at the time of attachment.

(15) The conductor piece 50 is provided to form a part of an electric circuit when the device 1 is attached to the electric circuit. The conductor piece 50 is a plate piece (plate-shaped part) made up of a first connection portion 51 and a second connection portion 52 at opposite ends and an intermediate cutting portion 53.

(16) The first connection portion 51 and the second connection portion 52 are provided to connect with another conductor (e.g., lead wire) in the electric circuit, while the cutting portion 53 is provided to break the electric circuit by being cut at the time of actuation.

(17) As shown in part (a) of FIG. 2, the cutting portion 53 has two first fragile portions 54a and 54b formed in a first surface 54 on the first end 11 side, and two second fragile portions 55a, 55b formed in a second surface 55 on the second end 12 side.

(18) The first fragile portions 54a and 54b are grooves formed in the width direction (direction perpendicular to the paper plane of FIG. 2) of the cutting portion 53, and having the same depths, widths, and lengths. The second fragile portions 55a and 55b are grooves formed in the width direction of the cutting portion 53, and having the same depths, widths, and lengths. The groove width of the first fragile portions 54a and 54b is narrower than the groove width of the second fragile portions 55a and 55b.

(19) The first fragile portions 54a and 54b are respectively formed in positions facing the second fragile portions 55a and 55b in the thickness direction of the cutting portion 53. The center axis (center of groove width) of the first fragile portion 54a coincides with the center axis (center of groove width) of the second fragile portion 55a, while the center axis (center of groove width) of the first fragile portion 54b coincides with the center axis (center of groove width) of the second fragile portion 55b.

(20) As shown in part (b) of FIG. 2, a length between the center axis of the first fragile portion 54a and the center axis of the first fragile portion 54b (L1) and a length of the tip end enlarged-diameter portion 42 of the projectile 40 (length of one side if the tip end enlarged-diameter portion 42 is a square) (L2) are the same (L1=L2).

(21) A hole 51a in the first connection portion 51 and a hole 52a in the second connection portion 52 are both provided to connect with another conductor (e.g., lead wire) in the electric circuit.

(22) Although in the conductor piece 50 of FIG. 1 the surface of the cutting portion 53 is orthogonal to the surfaces of the first connection portion 51 and the second connection portion 52, the surface of the cutting portion 53 may form the same plane as the surfaces of the first connection portion 51 and the second connection portion 52. That is, although the conductor piece 50 of FIG. 1 may be formed such that the part of the cutting portion 53 is bent toward the far side of the paper plane, the cutting portion 53 may instead be continuous with the first connection portion 51 and the second connection portion 52 to form one plate-shaped conductor piece.

(23) Moreover, of the conductor piece 50, a part close to the cutting portion 53 of the first connection portion 51 and a part close to the cutting portion 53 of the second connection portion 52 may be deformed in the thickness direction, depending on the shape and structure of an attachment portion 56 of the housing 10.

(24) The conductor piece 50 is disposed such that the surface of the cutting portion 53 is orthogonal to the axial direction of the housing 10. The first surface 54 of the cutting portion 53 of the conductor piece 50 on the first end 11 side faces the tip end surface 42a of the tip end enlarged-diameter portion 42 of the projectile 40. Although the first surface 54 of the cutting portion 53 and the tip end surface 42a abut on each other in FIG. 1, the parts may face each other with a gap in between.

(25) Additionally, if the sectional shape of the tip end enlarged-diameter portion 42 of the projectile 40 in the width direction is a square, the length L2 of one side and the width (W1 (direction perpendicular to the paper plane of FIG. 2, not shown)) of the cutting portion 53 preferably satisfy relationship L2W1, and more preferably is within the range of L2/W1=1.0-1.2.

(26) A box-shaped stopper 60 having one open surface and a bottom surface 62 as a surface facing the opening, is disposed between the conductor piece 50 and the second end 12 of housing, such that the opening side is on the conductor piece 50 side. The box-shaped stopper 60 is made of a synthetic resin, and the inside of the stopper 60 forms an insulating space 61.

(27) The bottom surface 62 of the box-shaped stopper 60 has a discharge path 64 for combustion products which penetrates in the thickness direction and serves as a part of a discharge path for combustion products. The discharge path 64 may be formed in a side surface 63 of the box-shaped stopper 60. If the discharge path 64 for combustion products is formed in the bottom surface 62, the discharge path 64 is preferably formed in the center of the bottom surface 62. If the discharge path 64 for combustion products is formed in the side surface 63, the discharge path 64 is preferably formed on the bottom surface 62 side of the side surface 63.

(28) A corner portion 65 of the opening of the box-shaped stopper 60 is positioned on the outer side of the center axis (center of groove width) of the second fragile portion 55a or 55b. Hence, the opening is larger than the distance between the center axes of the second fragile portions 55a and 55b.

(29) At the time of actuation, the tip end enlarged-diameter portion 42 of the projectile 40 moves in the axial direction to cut the cutting portion 53 of the conductor piece 50, and then the tip end enlarged-diameter portion 42 and a cut piece 50a of the cutting portion 53 enter the insulating space 61, whereby the electric circuit is broken by cutting the cutting portion 53.

(30) In the electric circuit breaker device 1 of FIG. 1, a stainless steel reinforcing frame 70 is disposed within the resin housing 10 outside of the cylinder 30. As shown in FIGS. 1 and 3, the reinforcing frame 70 is U-shaped in plan view, and has a base plate 71, and a first side plate 72 and a second side plate 73 extend in the same direction from lengthwise opposite ends of the base plate 71.

(31) A gas passage hole 71a penetrates the base plate 71 in the thickness direction. The first side plate 72 is narrowed between the base plate 71 and the tip end 72a to have a first recess 72b. The second side plate 73 is narrowed between the base plate 71 and the tip end 73a to have a second recess 73b. The first recess 72b and the second recess 73b are recesses (parts from which the first side plate 72 and the second side plate 73 are cut out) having the same widths and lengths, and are formed at opposing positions.

(32) In parts of the first side plate 72 excluding the first recess 72b (parts on both sides of the first recess 72b in length direction), two circular through holes 74a and 74b are formed to reduce weight without decreasing the strength of the reinforcing frame 70. In parts of the second side plate 73 excluding the second recess 73b (parts in both sides of the second recess 73b in length direction), two circular through holes 75a and 75b are formed to reduce weight without decreasing the strength of the reinforcing frame 70.

(33) The reinforcing frame 70 may be embedded in the resin housing 10 as a whole, or both side surfaces 76a and 76b of the first side plate 72, both side surfaces 77a and 77b of the second side plate 73, and both side surfaces 78a and 78b of the base plate 71 may be partially or entirely exposed.

(34) The reinforcing frame 70 is disposed to outwardly surround the box-shaped stopper 60 (insulating space 61) and the cylinder 30 with spacing, such that the base plate 71 is in the second end 12 side, and the tip end 72a of the first side plate 72 and the tip end 73a of the second side plate 73 are in the first end 11 side.

(35) Moreover, the reinforcing frame 70 is disposed such that the first connection portion 51 and the second connection portion 52 of the conductor piece 50 respectively extend across the first recess 72b and the second recess 73b. For this reason, the first connection portion 51 and the second connection portion 52 of the conductor piece 50 do not come into contact with the first side plate 72 and the second side plate 73 of the reinforcing frame 70.

(36) The discharge path 64 for combustion products formed in the bottom surface 62 of the box-shaped stopper 60 communicates with the gas passage hole 71a formed in the base plate 71 of the reinforcing frame 70, and the gas passage hole 71a also faces the cylindrical space 13 in the second end 12 side. Hence, these portions form a discharge path for combustion products formed between the insulating space 61 and the second end 12 of the housing. In other words, the gas passage hole 71a of the base plate 71 forms a part of the discharge path for combustion products.

(37) The electric circuit breaker device 1 shown in FIG. 1 can be assembled in the same manner as the electric circuit breaker device 1 shown in FIG. 1 of JP-A 2016-85947. Note, however, that the housing 10 can be produced by performing injection molding (insert molding) with the reinforcing frame 70 placed inside a mold.

(38) A gap allowing passage of combustion products including combustion gas generated by actuation of the igniter 20 may be formed between an inner circumferential surface of the cylinder 30 and an outer circumferential surface of the rod 41 of the projectile 40.

(39) In the electric circuit breaker device 1 shown in FIG. 1, the cylinder 30 and the reinforcing frame 70 made of metal or the like are disposed inside the housing 10 to reinforce the resin housing 10. Hence, the thickness of the resin housing 10 can be reduced, and the entire device can be downsized. In the electric circuit breaker device 1 shown in FIG. 1, the thickness of the housing 10 can be reduced by about 30 to 80% as compared to cases where the cylinder 30 and the reinforcing frame 70 are not used.

(40) Next, an operation will be described of a case where the electric circuit breaker device 1 shown in FIG. 1 is disposed in a part of an electric circuit of an electric vehicle. The electric circuit breaker device 1 shown in FIG. 1 may be combined with a sensor or the like that detects abnormal currents, and may automatically start operation when an abnormal current flows in an electric circuit, for example, or may be actuated manually.

(41) To dispose the electric circuit breaker device 1 in an electric circuit, the electric circuit breaker device 1 is connected with a lead wire forming the electric circuit at the hole 51a in the first connection portion 51 and the hole 52a in the second connection portion 52 of the conductor piece 50. When an abnormality occurs in the electric circuit, the igniter 20 is actuated, and combustion products are generated from the ignition portion 21.

(42) Since the ignition portion 21 is surrounded by the first end opening 31 side of the cylinder 30, the generated combustion products move straight through the cylinder 30, and collide with the rod 41 of the projectile 40. Thus, the high-temperature combustion products move through the cylinder 30 made of metal or the like and collide with the projectile 40, whereby the inner wall surface 13a of the cylindrical space 13 is not directly exposed to heat and pressure of the combustion products.

(43) Moreover, since the reinforcing frame 70 is disposed in the resin housing 10, resistance to internal pressure at the time of actuation is improved, and long-term (life expectancy of electric vehicle) durability is also improved. Thus, since the cylinder 30 and the reinforcing frame 70 are provided, the thickness of the resin housing 10 can be reduced, and the device 1 itself can be downsized.

(44) Upon receipt f the pressure of the combustion product, the projectile 40 moves in the axial direction, and cuts the cutting portion 53 of the conductor piece 50 with the tip end enlarged-diameter portion 42. Then, as shown in FIG. 4, the tip end enlarged-diameter portion 42 and the cut piece 50a of the cutting portion 53 move into the insulating space 61, and are held in an electrically insulated manner. With this operation, the first connection portion 51 and the second connection portion 52 at both ends of the conductor piece 50 are electrically interrupted, and the electric circuit in which the device 1 is disposed is broken.

(45) In such a process, a part of the combustion products generated from the igniter 20 passes between the cylinder 30 and the projectile 40 to arrive at the insulating space 61, and thereafter passes through the discharge path for combustion products (the discharge path 64 for combustion products, the gas passage hole 71a, and the cylindrical space 13 on the second end 12 side) to be discharged to the outside.

(46) After the conductor piece 50 is cut at the cutting portion 53, even if an arc is generated between the first connection portion 51 and the second connection portion 52, the arc is promptly extinguished by the combustion products discharged through the discharge path for combustion products. Hence, there is no electrical conduction between the first connection portion 51 and the second connection portion 52, and peripheral members are not fused.

(47) Note that since the combustion products discharged from the discharge path are only a small amount, the combustion products do not affect the cutting of the cutting portion 53 by the movement of the bar-shaped projectile 40. The output of the igniter 20 can also be adjusted by taking into account the discharged amount of combustion products according to need.

INDUSTRIAL APPLICABILITY

(48) The electric circuit breaker device of the present invention can be arranged in various electric circuits, and is particularly appropriate for an electric circuit including an automobile battery (e.g., lithium ion battery), an electric circuit of an electric vehicle, and an electric circuit of home appliances.

REFERENCE SIGNS LIST

(49) 1 electric circuit breaker device 10 housing 13 cylindrical space 20 igniter 30 cylinder 40 projectile 41 rod 42 tip end enlarged-diameter portion 50 conductor piece 51 first connection portion 52 second connection portion 53 cutting portion 54a, 54b first fragile portion 55a, 55b second fragile portion 60 box-shaped stopper 63 discharge path for combustion products 70 reinforcing frame 71 base plate 71a gas passage hole 72 first side plate 72b first recess 73 second side plate 73b second recess