Patent Description:
An electric circuit breaker device as described in the preamble of claim <NUM> is already known from <CIT>. An electric circuit may be provided with a breaker device configured to be actuated when an abnormality occurs in a device constituting the electric circuit or when an abnormality occurs in a system in which the electric circuit is mounted, thereby urgently interrupting the continuity of the electric circuit. Electric circuit breaker devices have been proposed in which, according to one aspect thereof, a projectile is moved at high speed by energy applied from an igniter or the like to forcibly and physically cut a conductor piece that forms a portion of the electric circuit (refer to Patent Documents <NUM> to <NUM> and the like, for example). Further, in recent years, electric circuit breaker devices applied to electric vehicles equipped with a high-voltage power source are becoming increasingly important.

In an electric circuit breaker device, an arc is likely to occur when a conductor piece forming a portion of an electric circuit is cut. When an arc occurs, the electric circuit cannot be interrupted quickly, and thus the electric circuit breaker device must quickly extinguish the generated arc.

The technique of the present disclosure has been made in view of the circumstances described above, and an object thereof is to provide an electric circuit breaker device capable of quickly extinguishing an arc that occurs during actuation.

The above and other objects of the invention are achieved by the electric circuit breaker device according to claim <NUM>. Preferred embodiments are claimed in the dependent claims. In order to solve the problems described above, in the present disclosure, a coolant material having a fibrous form is arranged in an arc-extinguishing region formed in a housing of an electric circuit breaker device and configured to receive a cutoff portion of a conductor piece.

More specifically, an electric circuit breaker device according to the present disclosure includes an igniter provided to a housing, a projectile disposed in a cylindrical space formed in the housing, the projectile being movable in the cylindrical space by energy received from the igniter, a conductor piece that is provided to the housing, forms a portion of an electric circuit, includes a cutoff portion to be cut off by the projectile in a portion thereof, and is disposed with the cutoff portion crossing the cylindrical space, an arc-extinguishing region positioned within the cylindrical space, on a side opposite to the projectile prior to actuation of the igniter with the cutoff portion interposed between the arc-extinguishing region and the projectile, and configured to receive the cutoff portion cut off by the projectile, and a coolant material having a fibrous form and disposed in the arc-extinguishing region.

Here, the coolant material is formed from a metal fiber material. Further, the coolant material may be formed from steel wool.

Further, the arc-extinguishing region may include a first arc-extinguishing region adjacent to the cutoff portion disposed crossing the cylindrical space prior to actuation of the igniter and a second arc-extinguishing region positioned on a side opposite to the cutoff portion with the first arc-extinguishing region interposed between the second arc-extinguishing region and the cutoff portion, the first arc-extinguishing region may have a width dimension in a transverse cross-sectional direction that corresponds to a width dimension in a transverse cross-sectional direction of the cutoff portion, and the second arc-extinguishing region may have a transverse cross-sectional area greater than a transverse cross-sectional area of the first arc-extinguishing region.

According to the present disclosure, it is possible to provide an electric circuit breaker device capable of quickly extinguishing an arc that occurs during actuation.

An electric circuit breaker device according to an embodiment of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited by the embodiments and is limited only by the claims.

<FIG> is a perspective view of an electric circuit breaker device (hereinafter simply referred to as "breaker device") <NUM>. <FIG> is a drawing illustrating an internal structure of the breaker device <NUM> in a height direction (direction in which a cylindrical space <NUM> described later extends). The breaker device <NUM> is a device configured to interrupt an electric circuit included in a vehicle, an electric home appliance, or the like when an abnormality occurs in the electric circuit or in a system including a lithium battery (lithium ion battery, for example) of the electric circuit, thereby preventing great damage. In the present specification, a cross section of the breaker device <NUM> in the height direction (direction in which the cylindrical space <NUM> described later extends) is referred to as a vertical cross section of the breaker device <NUM>, and a cross section in a direction orthogonal to the vertical cross section is referred to as a transverse cross section of the breaker device <NUM>. Further, <FIG> illustrates a state prior to actuation of the breaker device <NUM>.

The breaker device <NUM> includes a housing <NUM>, an igniter <NUM>, a projectile <NUM>, a conductor piece <NUM>, and the like. <FIG> is an exploded view of the housing <NUM>. The housing <NUM> includes the cylindrical space <NUM> that extends in a direction from a first end portion <NUM> to a second end portion <NUM>. This cylindrical space <NUM> is a space formed in a straight line, making the projectile <NUM> described later movable. Then, the igniter <NUM> is provided on the first end portion <NUM> side of the breaker device <NUM>. The igniter <NUM> includes an ignition portion <NUM> with an ignition charge, and an igniter body <NUM> including a conduction pin <NUM> connected to the ignition portion <NUM>. The igniter body <NUM> is surrounded by an insulating resin. Further, the conduction pin <NUM> of the igniter body <NUM> is exposed to the outside, and is connected to a power source when the breaker device <NUM> is used.

The housing <NUM> includes a housing body <NUM> and a cylinder <NUM> attached to an upper portion of the housing body <NUM>. That is, an outer shell of the breaker device <NUM> is formed including the housing body <NUM> and the cylinder <NUM>.

In the example illustrated in <FIG>, the housing body <NUM> has a substantially rectangular parallelepiped shape as a whole. and includes, from the top, a top lid housing portion <NUM>, a central housing portion <NUM>, and a bottom lid housing portion <NUM>. However, the shape of the housing body <NUM> is not particularly limited. Further, the top lid housing portion <NUM> and the central housing portion <NUM>, and the central housing portion <NUM> and the bottom lid housing portion <NUM> are respectively fixed using known fasteners, for example, thereby integrating the housing body <NUM>.

The central housing portion <NUM> is formed from an insulating member such as a synthetic resin or the like. For example, the central housing portion <NUM> may be formed from nylon, which is a type of polyamide synthetic resin. Further, the central housing portion <NUM> has a substantially prismatic shape.

The central housing portion <NUM> includes a cavity portion <NUM> formed therethrough in a vertical direction from an upper end surface 120A to a lower end surface 120B of the central housing portion <NUM>. The cavity portion <NUM> includes a small diameter cavity portion 121A disposed on the upper end surface 120A side of the central housing portion <NUM>, and a large diameter cavity portion 121B disposed on the lower end surface 120B side of the central housing portion <NUM>. Both the small diameter cavity portion 121A and the large diameter cavity portion 121B are cavity portions of a cylindrical shape having a circular transverse cross section, and a diameter of the small diameter cavity portion 121A is smaller than a diameter of the large diameter cavity portion 121B. Further, the small diameter cavity portion 121A and the large diameter cavity portion 121B are coaxially disposed. Furthermore, in the central housing portion <NUM>, a pair of conductor piece insertion portions <NUM> for inserting the conductor piece <NUM> are provided passing through the central housing portion <NUM> in a transverse cross-sectional direction.

The bottom lid housing portion <NUM> in the present embodiment is, for example, a flat plate member having a square outer shape corresponding to that of the central housing portion <NUM>. Further, in the example illustrated in <FIG>, the bottom lid housing portion <NUM> has a two-layer structure. More specifically, the bottom lid housing portion <NUM> has a layered structure in which an interior portion <NUM> facing the central housing portion <NUM> side and an exterior portion <NUM> facing the outside are integrally joined.

The interior portion <NUM> of the bottom lid housing portion <NUM>, similar to the central housing portion <NUM>, is formed from an insulating member such as a synthetic resin. The interior portion <NUM>, similar to the central housing portion <NUM>, may also be formed from nylon, which is a type of polyamide synthetic resin. Further, the exterior portion <NUM> of the bottom lid housing portion <NUM> is formed from an appropriate metal member, such as stainless steel or aluminum, having excellent strength and durability. However, the mode described above of the bottom lid housing portion <NUM> is exemplary. For example, the bottom lid housing portion <NUM> as a whole may be formed from an insulating member.

The top lid housing portion <NUM> is, for example, a member having a square outer shape corresponding to that of the central housing portion <NUM>. As illustrated in <FIG>, a cavity portion <NUM> for pressing the cylinder <NUM> is formed in the vertical direction, from an upper end 110A to a lower end 110B, at a transverse cross-sectional center of the top lid housing portion <NUM>. The top lid housing portion <NUM>, similar to the exterior portion <NUM> of the bottom lid housing portion <NUM>, is formed from an appropriate metal member, such as stainless steel or aluminum, having excellent strength and durability. The cavity portion <NUM> of the top lid housing portion <NUM> includes a small diameter cavity portion 111A disposed on the upper end 110A side of the top lid housing portion <NUM>, and a large diameter cavity portion 111B disposed on the lower end 110B side of the top lid housing portion <NUM>. Both the small diameter cavity portion 111A and the large diameter cavity portion 111B are cavity portions having a circular transverse cross section, and a diameter of the small diameter cavity portion 111A is smaller than a diameter of the large diameter cavity portion 111B. Further, the small diameter cavity portion 111A and the large diameter cavity portion 111B of the top lid housing portion <NUM> are coaxially disposed. Furthermore, a stepped surface <NUM> extending in the transverse cross-sectional direction of the top lid housing portion <NUM> and caused by these diameter differences is formed at a boundary portion between the small diameter cavity portion 111A and the large diameter cavity portion 111B.

Next, details of the cylinder <NUM> will be described. The cylinder <NUM> is a cylindrical member having a stepped cylindrical shape, and an upper end side and a lower end side are both formed as open ends. The cylinder <NUM>, similar to the top lid housing portion <NUM> and the like, is formed from an appropriate metal member, such as stainless steel or aluminum, having excellent strength and durability.

When described in greater detail, the cylinder <NUM> includes a small diameter portion <NUM> disposed on the upper end side, a large diameter portion <NUM> disposed on the lower end side, and a stepped portion <NUM> that connects these. The small diameter portion <NUM> and the large diameter portion <NUM> each have a substantially cylindrical shape, and a diameter of the small diameter portion <NUM> is smaller than a diameter of the large diameter portion <NUM>. The small diameter portion <NUM> and the large diameter portion <NUM> of the cylinder <NUM> are coaxially disposed with a center axis extending in the vertical direction, and the stepped portion <NUM> extends in the transverse cross-sectional direction (radial direction) of the cylinder <NUM>. Further, reference sign 33A denotes an inner wall surface of the stepped portion <NUM>.

Reference sign 31A indicated in <FIG> denotes an inner circumferential surface of the small diameter portion <NUM>. As illustrated in <FIG>, in the small diameter portion <NUM> of the cylinder <NUM>, the igniter <NUM> is pressed to the inner circumferential surface 31A, thereby fixing the igniter <NUM> to the small diameter portion <NUM>, for example. Furthermore, an upper end side of the small diameter portion <NUM> of the cylinder <NUM> is formed folded toward an inner side in the radial direction, for example, and thus an upper end collar portion <NUM> is formed on the upper end side of the small diameter portion <NUM>. An edge portion of the upper end collar portion <NUM> has an annular shape, and an opening <NUM> is formed on an inner side thereof.

Here, as illustrated in <FIG>, the igniter body <NUM> of the igniter <NUM> includes a body portion <NUM> having a cylindrical shape and housed in the small diameter portion <NUM> of the cylinder <NUM>, and a connector portion <NUM> exposed to the outside of the cylinder <NUM> (housing <NUM>) through the opening <NUM>. The body portion <NUM> of the igniter <NUM> is pressed to the inner circumferential surface 31A of the small diameter portion <NUM> of the cylinder <NUM>, and thus fixed to the inner circumferential surface 31A. More specifically, the body portion <NUM> of the igniter <NUM> has an outer diameter of an intermediate portion in the vertical direction that is slightly small compared to other locations, and a constricted portion <NUM> is formed as an annular recess due to this difference in outer diameters. An O-ring <NUM> made of rubber (silicone rubber, for example) or a synthetic resin is fitted into the constricted portion <NUM> of the body portion <NUM>, thereby increasing airtightness between the inner circumferential surface 31A of the cylinder <NUM> and the body portion <NUM> of the igniter <NUM>. Further, the connector portion <NUM> of the igniter <NUM> has a cylindrical shape covering a side of the conduction pin <NUM>, as illustrated in <FIG>, allowing connection with a connector of a power source.

Next, details of the large diameter portion <NUM> of the cylinder <NUM> will be described. Reference sign 32A indicated in <FIG> denotes an inner circumferential surface of the small diameter portion <NUM>. As illustrated in <FIG>, a piston portion <NUM> of the projectile <NUM> is slidably disposed along the inner circumferential surface 32A on an inner side of the large diameter portion <NUM> of the cylinder <NUM>. Further, as illustrated in <FIG> and <FIG>, a lower end side of the large diameter portion <NUM> of the cylinder <NUM> is formed folded toward an outer side in the radial direction, for example, and thus a lower end collar portion <NUM> is formed on the lower end side of the large diameter portion <NUM>. Here, an outer diameter of the large diameter portion <NUM> of the cylinder <NUM> is equal to the diameter of the small diameter cavity portion 111A of the top lid housing portion <NUM>. Further, an outer diameter of the lower end collar portion <NUM> of the cylinder <NUM> is equal to the diameter of the large diameter cavity portion 111B of the top lid housing portion <NUM>. In the breaker device <NUM> according to the present embodiment, the lower end collar portion <NUM> of the cylinder <NUM> is disposed in the large diameter cavity portion 111B of the top lid housing portion <NUM>, and the cylinder <NUM> is assembled to the housing body <NUM> with the lower end collar portion <NUM> engaged with the stepped surface <NUM> of the top lid housing portion <NUM>. As a result, the cylinder <NUM> is integrally fixed to the housing body <NUM>. Note that an inner diameter of the large diameter portion <NUM> of the cylinder <NUM> is larger than the diameter of the small diameter cavity portion 121A of the central housing portion <NUM>.

Further, a groove portion <NUM> having an annular shape is formed in the upper end surface 120A of the central housing portion <NUM>, and an O-ring <NUM> made of rubber (silicone rubber, for example) or a synthetic resin is fitted into this groove portion <NUM> in a state of abutting the lower end collar portion <NUM> of the cylinder <NUM>. When the cylinder <NUM> is assembled to the housing body <NUM>, the O-ring <NUM> disposed in the groove portion <NUM> of the central housing portion <NUM> is compressed by the lower end collar portion <NUM> of the cylinder <NUM>, thereby further increasing the airtightness between the cylinder <NUM> and the housing body <NUM>. Further, a region of the upper end surface 120A of the central housing portion <NUM> that faces the inner side of the large diameter portion <NUM> of the cylinder <NUM> is referred to as a stopper portion <NUM>.

Next, the details of the projectile <NUM> will be described. <FIG> is a side view of the projectile <NUM>. The projectile <NUM> is formed from an insulating member, such as a synthetic resin, and includes the piston portion <NUM> and a rod portion <NUM> having a rod shape and connected to the piston portion <NUM>. Both the piston portion <NUM> and the rod portion <NUM> are substantially cylindrical bodies, and an outer diameter of the piston portion <NUM> is greater than an outer diameter of the rod portion <NUM>. Further, the piston portion <NUM> and the rod portion <NUM> of the projectile <NUM> are coaxially disposed. Further, reference sign 410A indicated in <FIG> denotes an upper end surface of the piston portion <NUM>, and reference sign 410B denotes a lower end surface of the piston portion <NUM>. The upper end surface 410A of the piston portion <NUM> has a recessed curved shape with a center portion in a planar direction being the deepest. However, the shape of the upper end surface 410A of the piston portion <NUM> is not limited to the mode described above, and may be formed as a flat surface.

Further, reference sign 420A denotes a lower end surface of the rod portion <NUM>. The upper end surface 410A of the piston portion <NUM> can be referred to as an upper end surface of the projectile <NUM>, and the lower end surface 420A of the rod portion <NUM> can be referred to as a lower end surface of the projectile <NUM>. In the following, the vertical direction illustrated in <FIG> is defined as the vertical direction of the projectile <NUM>. The vertical direction of the projectile <NUM> coincides with an axial direction of the piston portion <NUM> and the rod portion <NUM>. Further, of the rod portion <NUM> of the projectile <NUM>, the side connected to the piston portion <NUM> may be referred to as a base end side, and the opposite side, that is, the side where the lower end surface 420A is positioned, may be referred to as a tip end side.

The outer diameter of the piston portion <NUM> is slightly smaller than the inner diameter of the large diameter portion <NUM> of the cylinder <NUM>. Further, the piston portion <NUM> has an outer diameter of an intermediate portion in the vertical direction that is formed slightly small compared to other locations, and a constricted portion <NUM> is formed as an annular recess due to this difference in outer diameters. An O-ring <NUM> made of rubber (silicone rubber, for example) or a synthetic resin is fitted into the constricted portion <NUM> of the piston portion <NUM>. In the state illustrated in <FIG>, the O-ring <NUM> fitted into the constricted portion <NUM> of the piston portion <NUM> abuts the inner circumferential surface 32A of the large diameter portion <NUM> of the cylinder <NUM>, and is thereby compressed. Thus, an appropriate sealing property is exhibited by the O-ring <NUM>. Further, the outer diameter of the rod portion <NUM> of the projectile <NUM> is slightly smaller than the diameter of the small diameter cavity portion 121A in the central housing portion <NUM>.

Next, details of the conductor piece <NUM> will be described. <FIG> is a plan view of the conductor piece <NUM>. The conductor piece <NUM> is a metal body having conductivity that constitutes a portion of the components of the breaker device <NUM> and, when the breaker device <NUM> is attached to a predetermined electric circuit, forms a portion of the electric circuit, and may be referred to as a bus bar. The conductor piece <NUM> can be formed from a metal such as copper (Cu), for example. However, the conductor piece <NUM> may be formed from a metal other than copper, or may be formed from an alloy of copper and another metal. Note that examples of metals other than copper included in the conductor piece <NUM> include manganese (Mn), nickel (Ni), and platinum (Pt).

In the example illustrated in <FIG>, the conductor piece <NUM> is formed as an elongated flat plate piece as a whole, and includes a first connecting end portion <NUM> and a second connecting end portion <NUM> on both end sides, a cutoff portion <NUM> positioned in an intermediate portion therebetween, and the like. Connection holes 51A, 52A are provided in the first connecting end portion <NUM> and the second connecting end portion <NUM> of the conductor piece <NUM>, respectively. These connection holes 51A, 52A are used to connect with other conductors (lead wires, for example) in the electric circuit. The cutoff portion <NUM> of the conductor piece <NUM> is a portion forcibly and physically cut by the rod portion <NUM> of the projectile <NUM> and is cut off from the first connecting end portion <NUM> and the second connecting end portion <NUM> when an abnormality such as excessive current occurs in the electric circuit to which the breaker device <NUM> is applied. Notches (slits) <NUM> are formed at both ends of the cutoff portion <NUM> of the conductor piece <NUM>, making it easy to cut and cut off the cutoff portion <NUM>.

Here, various forms of the conductor piece <NUM> can be adopted, and a shape thereof is not particularly limited. While, in the example illustrated in <FIG>, surfaces of the first connecting end portion <NUM>, the second connecting end portion <NUM>, and the cutoff portion <NUM> form the same surface, the form is not limited thereto. For example, the conductor piece <NUM> may be connected such that the cutoff portion <NUM> is orthogonal to or inclined relative to the first connecting end portion <NUM> and the second connecting end portion <NUM>. Further, the planar shape of the cutoff portion <NUM> of the conductor piece <NUM> is not particularly limited, either. Of course, the shapes of the first connecting end portion <NUM> and the second connecting end portion <NUM> of the conductor piece <NUM> are not particularly limited, either.

The conductor piece <NUM> configured as described above is inserted through the pair of conductor piece insertion portions <NUM> provided to the central housing portion <NUM> of the housing body <NUM>, and is thus held in the central housing portion <NUM> in a state of crossing the small diameter cavity portion 121A of the central housing portion <NUM> (refer to <FIG>). Note that, in the central housing portion <NUM> of the housing body <NUM>, the conductor piece <NUM> is mounted on mounting surfaces 124A that define lower surfaces of the pair of conductor piece insertion portions <NUM> (refer to <FIG>). Each of the mounting surfaces 124A of the pair of conductor piece insertion portions <NUM> is formed as a flat surface extending in a direction orthogonal to the extending direction (axial direction) of the cylindrical space <NUM>. Therefore, when the first connecting end portion <NUM> and the second connecting end portion <NUM> of the conductor piece <NUM> are respectively mounted on the mounting surfaces 124A provided to the central housing portion <NUM>, the conductor piece <NUM> crosses the cylindrical space <NUM> and is held in a manner orthogonal to the extending direction (axial direction) of the cylindrical space <NUM>.

Note that <FIG> is a diagram illustrating a planar positional relationship between the small diameter cavity portion 121A and the conductor piece <NUM> in a state where the conductor piece <NUM> is disposed in the central housing portion <NUM> of the breaker device <NUM>. As illustrated in <FIG>, the conductor piece <NUM> is disposed in the central housing portion <NUM> in such a manner that the cutoff portion <NUM> is included in the region of the small diameter cavity portion 121A. Further, the conductor piece <NUM> is disposed with an outer edge L1 (illustrated in <FIG>) of the small diameter cavity portion 121A of the central housing portion <NUM> planarly overlapping the positions of the notches <NUM> of the conductor piece <NUM>.

Returning to <FIG> and <FIG>, the configuration of the breaker device <NUM> will be described. In the cylindrical space <NUM> formed in the housing <NUM>, the igniter <NUM>, the projectile <NUM>, and the conductor piece <NUM> are disposed in this order from the first end portion <NUM> side in the vertical direction of the breaker device <NUM>. Further, <FIG> is a diagram illustrating an internal structure of the breaker device <NUM> in a height direction (direction in which the cylindrical space <NUM> described later extends), without the projectile <NUM> being illustrated for the sake of convenience. In the breaker device <NUM> according to the present embodiment, the cylindrical space <NUM> of the housing <NUM> is formed by respectively connecting, in the vertical direction, a cylinder cavity portion <NUM> formed inside the large diameter portion <NUM> of the cylinder <NUM>, and the small diameter cavity portion 121A and the large diameter cavity portion 121B of the housing body <NUM> (central housing portion <NUM>). That is, the cylindrical space <NUM> is configured to include the cylinder cavity portion <NUM>, the small diameter cavity portion 121A, and the large diameter cavity portion 121B of the breaker device <NUM>.

As illustrated in <FIG>, <FIG>, and the like, the ignition portion <NUM> of the igniter <NUM> is disposed facing the inside of the cylindrical space <NUM> (more specifically, the cylinder cavity portion <NUM>) of the housing <NUM>. Accordingly, when the igniter <NUM> is actuated, a combustion product generated by the combustion of the ignition charge of the igniter <NUM> is discharged into the cylindrical space <NUM> (cylinder cavity portion <NUM>). Further, as illustrated in <FIG>, the projectile <NUM> is housed in the cylindrical space <NUM> of the housing <NUM> with the piston portion <NUM> positioned on an upper side and the rod portion <NUM> positioned on a lower side. Specifically, the upper end surface 410A of the piston portion <NUM> of the projectile <NUM> is disposed facing the ignition portion <NUM> of the igniter <NUM>.

Further, in the breaker device <NUM>, a length of the projectile <NUM> in the axial direction is configured to be substantially equal to a separation distance in the vertical direction of the housing <NUM> between an upper surface 53A (refer to <FIG>, <FIG>, and the like) of the cutoff portion <NUM> of the conductor piece <NUM> installed in the housing <NUM> and the stepped portion <NUM> of the cylinder <NUM>. Thus, prior to actuation of the breaker device <NUM> (igniter <NUM>), the projectile <NUM> is positioned in the cylindrical space <NUM> with an outer circumferential edge of the upper end surface 410A of the piston portion <NUM> of the projectile <NUM> abutting the inner wall surface 33A of the stepped portion <NUM> of the cylinder <NUM>, and the lower end surface 420A of the rod portion <NUM> abutting the upper surface 53A of the cutoff portion <NUM> of the conductor piece <NUM>. Hereinafter, the position of the projectile <NUM> thus positioned is referred to as an "initial position". However, in this initial position, the lower end surface 420A of the rod portion <NUM> of the projectile <NUM> and the upper surface 53A of the cutoff portion <NUM> of the conductor piece <NUM> may be disposed facing each other with a gap therebetween.

Further, prior to actuation of the breaker device <NUM> (igniter <NUM>), the cylindrical space <NUM> of the housing <NUM> is vertically separated (divided into two parts) by the conductor piece <NUM> (cutoff portion <NUM>) disposed crossing the cylindrical space <NUM>. Hereinafter, within the cylindrical space <NUM> of the housing <NUM> separated by the cutoff portion <NUM> of the conductor piece <NUM>, a region (space) in which the projectile <NUM> is disposed is referred to as a "projectile initial arrangement region R1" (refer to <FIG>), and a region (space) positioned on the opposite side of the projectile <NUM> is referred to as an "arc-extinguishing region R2" (refer to <FIG>). As is clear from <FIG> and the like, the arc-extinguishing region R2 in the cylindrical space <NUM> of the present embodiment is formed as an insulating closed space including the whole large diameter cavity portion 121B and a portion of the small diameter cavity portion 121A.

Further, within the arc-extinguishing region R2, a region formed by the small diameter cavity portion 121A is referred to as a "first arc-extinguishing region R21", and a region formed by the large diameter cavity portion 121B is referred to as a "second arc-extinguishing region R22". Here, the first arc-extinguishing region R21 is a region adjacent to the cutoff portion <NUM> of the conductor piece <NUM> disposed crossing the cylindrical space <NUM> prior to actuation of the igniter <NUM>, and extends above the second arc-extinguishing region R22. Further, the second arc-extinguishing region R22 is a region positioned on the opposite side of the cutoff portion <NUM> with the first arc-extinguishing region R21 interposed between the second arc-extinguishing R22 and the cutoff portion <NUM>, and extends below the first arc-extinguishing region R21. In the present embodiment, a transverse cross-sectional area of the second arc-extinguishing region R22 is greater than a transverse cross-sectional area of the first arc-extinguishing region R21. More specifically, a width dimension of the first arc-extinguishing region R21 in the transverse cross-sectional direction (corresponding to a diameter of the first arc-extinguishing region R21 (small diameter cavity portion 121A) in the present embodiment) corresponds to a width dimension of the cutoff portion <NUM> in the transverse cross-sectional direction, and the transverse cross-sectional area of the second arc-extinguishing region R22 is greater than the transverse cross-sectional area of the first arc-extinguishing region R21.

In the present embodiment, the arc-extinguishing region R2 of the breaker device <NUM> has significance as a space for receiving the cutoff portion <NUM> cut off from the first connecting end portion <NUM> and the second connecting end portion <NUM> of the conductor piece <NUM> by the projectile <NUM> and, at the same time, as a space for effectively extinguishing the arc generated when the projectile <NUM> cuts off the cutoff portion <NUM>. Then, in order to effectively extinguish the arc generated when the cutoff portion <NUM> is cut off from the conductor piece <NUM>, in the present embodiment, the arc-extinguishing region R2 is filled with a coolant material having a fibrous form (hereinafter referred to as a "fibrous coolant material") <NUM> as an arc-extinguishing material (refer to <FIG>). The fibrous coolant material <NUM> is a coolant material having a fibrous form that removes thermal energy of the arc generated and the cutoff portion <NUM> when the projectile <NUM> cut off the cutoff portion <NUM>, and cools the arc and the cutoff portion <NUM>. While the type of the fibrous coolant material <NUM> is not particularly limited, steel wool is employed as the fibrous coolant material <NUM> in the present embodiment. Note that, in <FIG>, for the sake of convenience, a range of the fibrous coolant material <NUM> disposed in the arc-extinguishing region R2 is indicated by hatching. While, in <FIG>, a mode is illustrated in which the arc-extinguishing region R2 is entirely filled with the fibrous coolant material <NUM>, the fibrous coolant material <NUM> may be disposed occupying a portion of the arc-extinguishing region R2. For example, the fibrous coolant material <NUM> may be disposed only in the second arc-extinguishing region R22 of the arc-extinguishing region R2, and the first arc-extinguishing region R21 may be a cavity. Of course, the mode of installation of the fibrous coolant material <NUM> in the arc-extinguishing region R2 is not limited to these examples, and various modes can be adopted.

The breaker device <NUM> configured as described above includes an abnormality detection sensor (not illustrated) configured to detect an abnormal current of the electric circuit, and a control unit (not illustrated) configured to control the actuation of the igniter <NUM>. In addition to the current flowing through the conductor piece <NUM>, the abnormality detection sensor may be capable of detecting a voltage and a temperature of the conductor piece <NUM>. Further, the control unit is a computer capable of performing a predetermined function by executing a predetermined control program, for example. The predetermined function of the control unit may be realized by corresponding hardware. Then, when excessive current flows through the conductor piece <NUM> forming a portion of the electric circuit to which the breaker device <NUM> is applied, the abnormal current is detected by the abnormality detection sensor. The detected abnormal current is passed from the abnormality detection sensor to the controller. For example, the control unit is energized from an external power source (not illustrated) connected to the conduction pin <NUM> and actuates the igniter <NUM> based on the current value detected by the abnormality detection sensor. Here, the abnormal current may be a current value that exceeds a predetermined threshold value set for protection of a predetermined electric circuit. Note that the abnormality detection sensor and the control unit described above need not be included in the components of the breaker device <NUM>, and may be included in a device separate from the breaker device <NUM>, for example. Further, the abnormality detection sensor and the control unit are not essential components of the breaker device <NUM>.

When the igniter <NUM> is actuated, the ignition charge of the ignition portion <NUM> burns, and a combustion product, such as a combustion gas and flame, is discharged into the cylindrical space <NUM> (cylinder cavity portion <NUM>). A pressure (combustion energy) of the combustion product discharged from the ignition portion <NUM> into the cylindrical space <NUM> (cylinder cavity portion <NUM>) is communicated to the upper end surface 410A of the piston portion <NUM> of the projectile <NUM> disposed near and facing the ignition portion <NUM> in the initial position. As a result, the projectile <NUM> moves downward through the cylindrical space <NUM> in the extending direction (axial direction) of the cylindrical space <NUM>, and the rod portion <NUM> pressingly cuts the cutoff portion <NUM> from the conductor piece <NUM>, thereby cutting off the cutoff portion <NUM>. Here, the upper end surface 410A of the piston portion <NUM> of the projectile <NUM> has a recessed curved shape with a center portion in the planar direction being the deepest. Therefore, when the igniter <NUM> is actuated, the pressure of the combustion product discharged from the ignition portion <NUM> to the cylindrical space <NUM> (cylinder cavity portion <NUM>) is readily received by the upper end surface 410A of the piston portion <NUM>, making it possible to cause the lower end surface 420A of the rod portion <NUM> of the projectile <NUM> to vigorously collide with the cutoff portion <NUM> and cut off the cutoff portion <NUM>.

Upon actuation of the igniter <NUM>, the piston portion <NUM> of the projectile <NUM> is guided to the inner circumferential surface 32A of the large diameter portion <NUM> of the cylinder <NUM>, and moves downwardly along the inner circumferential surface 32A in the projectile initial arrangement region R1 (cylinder cavity portion <NUM>) of the cylindrical space <NUM>. At this time, while the O-ring <NUM> fitted into the constricted portion <NUM> of the piston portion <NUM> is in contact with the inner circumferential surface 32A of the cylinder <NUM>, an outer circumferential surface of the piston portion <NUM> other than the O-ring <NUM> is in completely non-contact with the inner circumferential surface 32A of the cylinder <NUM>. Further, an outer circumferential surface of the rod portion <NUM> of the projectile <NUM> is in completely non-contact with an inner circumferential surface of the small diameter cavity portion 121A of the central housing portion <NUM>. Thus, upon actuation of the igniter <NUM>, the projectile <NUM> can be moved smoothly along the extending direction (axial direction) of the cylindrical space <NUM> (projectile initial arrangement region R1), and the cutoff portion <NUM> of the conductor piece <NUM> can be suitably cut off. However, as long as the projectile <NUM> can be moved smoothly in the extending direction (axial direction) of the cylindrical space <NUM> when the igniter <NUM> is actuated, the shape and the dimensions of the projectile <NUM> can be freely determined, and the outer diameter of the piston portion <NUM> of the projectile <NUM> may be set to a dimension equal to the inner diameter of the large diameter portion <NUM> of the cylinder <NUM>, for example. Similarly, the outer diameter of the rod portion <NUM> of the projectile <NUM> may be set to a dimension equal to the diameter of the small diameter cavity portion 121A of the central housing portion <NUM>.

The projectile <NUM> moves downward in the extending direction (axial direction) of the cylindrical space <NUM> until the lower end surface 410B of the piston portion <NUM> abuts (collides with) the stopper portion <NUM> of the central housing portion <NUM>. <FIG> is a diagram illustrating a state after actuation of the igniter <NUM> of the breaker device <NUM>. In the state illustrated in <FIG>, the lower end surface 410B of the piston portion <NUM> of the projectile <NUM> abuts the stopper portion <NUM> of the central housing portion <NUM>, thereby positioning the projectile <NUM>. With actuation of the igniter <NUM>, the cutoff portion <NUM>, which has been cut off from the conductor piece <NUM> by the rod portion <NUM> of the projectile <NUM>, moves along with a tip end portion of the rod portion <NUM> into the arc-extinguishing region R2, which is an insulating closed space, is received by the arc-extinguishing region R2, and is thus held electrically isolated. Thus, the first connecting end portion <NUM> and the second connecting end portion <NUM> positioned on both ends of the conductor piece <NUM> are electrically disconnected, and the predetermined electric circuit to which the breaker device <NUM> is applied is forcibly interrupted.

In the breaker device I of the present embodiment, the fibrous coolant material <NUM> is disposed in the arc-extinguishing region R2. Therefore, at the moment when the cutoff portion <NUM> of the conductor piece <NUM> is cut off from the first connecting end portion <NUM> and the second connecting end portion <NUM> by the rod portion <NUM> of the projectile <NUM>, the cutoff portion <NUM> can be instantaneously buried in the fibrous coolant material <NUM> in the arc-extinguishing region R2 and quenched by the fibrous coolant material <NUM>. Thus, when the cutoff portion <NUM> is cut off from the conductor piece <NUM> constituting a portion of the predetermined electric circuit, the occurrence of the arc can be effectively suppressed. Further, when the electric circuit is interrupted by the breaker device <NUM>, even in a case where an arc is generated at the cut surface of the cutoff portion <NUM> of the conductor piece <NUM>, the generated arc can be quickly and effectively extinguished. This makes it possible to quickly interrupt the electric circuit to which the breaker device <NUM> is applied in a case where an abnormality is detected in the electric circuit, or the like. That is, by effectively suppressing a prolonged extinguishing of the arc generated when the electric circuit is interrupted, it is possible to suppress a prolonged interruption of the electric circuit. Further, according to the breaker device <NUM>, it is possible to suitably suppress the generation of a large spark or flame or the generation of a loud impact sound when the electric circuit is interrupted. Further, damage to the housing <NUM> and the like of the breaker device <NUM> caused by these can also be suppressed.

Further, as is clear in <FIG>, the breaker device <NUM> has a relative relationship between a stroke length of the piston portion <NUM> of the projectile <NUM>, a length of the first arc-extinguishing region R21 in the axial direction, and the like, causing the cutoff portion <NUM> cut off by the projectile <NUM> when the igniter <NUM> is actuated to be received in the second arc-extinguishing region R22 positioned below the first arc-extinguishing region R21. Thus, when the igniter <NUM> is actuated, the cutoff portion <NUM> is moved to the second arc-extinguishing region R22 having a large transverse cross-sectional area compared to that of the cutoff portion <NUM>, making it possible to more favorably cover a periphery of the cutoff portion <NUM>, particularly the cut surface of the cutoff portion <NUM>, with the fibrous coolant material <NUM>, and thus effectively remove the thermal energy from the cut surface of the cutoff portion <NUM>. As a result, the arc can be more rapidly extinguished.

Further, since the breaker device <NUM> according to the present embodiment employs the fibrous coolant material <NUM> as the arc-extinguishing material disposed in the arc-extinguishing region R2 of the cylindrical space <NUM> of the housing <NUM>, the breaker device <NUM> has the following advantages compared to a case where, for example, a powdered or granular arc-extinguishing material is employed. That is, moderate gaps are formed between fibers of the fibrous coolant material <NUM>, and thus the cutoff portion <NUM> cut off from the conductor piece <NUM> upon actuation of the igniter <NUM> and the tip end portion of the rod portion <NUM> can be readily pressed into the fibrous coolant material <NUM> and the cutoff portion <NUM> can be smoothly buried in the fibrous coolant material <NUM>. The periphery of the cutoff portion <NUM> received in the arc-extinguishing region R2 is surrounded by the fibrous coolant material <NUM>, and thus the cutoff portion <NUM> can be cooled more quickly, thereby allowing the arc to be more effectively extinguished.

Furthermore, because of the fibrous coolant material <NUM>, it is unlikely that an abnormal sound occurs even in a case where, for example, the breaker device <NUM> oscillates due to vibration or the like. For example, in a case where the breaker device <NUM> is mounted on a vehicle, the breaker device <NUM> is used in an environment that is subjected to vibration. In such an environment as well, the occurrence of a sound from the breaker device <NUM> that is unpleasant for the user can be suitably suppressed. In contrast, suppose a case where the arc-extinguishing region R2 of the breaker device <NUM> is filled with a powdered or granular arc-extinguishing material, the powdered or granular arc-extinguishing material readily moves in the arc-extinguishing region R2, and thus a so-called swishing sound is likely to occur. In particular, electric vehicles do not generate engine noise during travel and are excellent in quietness, and thus there is a risk that the swishing sound caused by the movement of the arc-extinguishing material within the housing will cause discomfort to the user. Further, in a case where the arc-extinguishing region R2 of the breaker device <NUM> is filled with a powdered or granular arc-extinguishing material as the arc-extinguishing material, the particles constituting the arc-extinguishing material rub against each other, resulting in a decrease in particle size over time and presumably failure to exhibit the desired arc-extinguishing performance in some cases. In contrast, because of the fibrous coolant material <NUM> in the present embodiment, the arc-extinguishing performance does not readily change over time, making it possible to constantly exhibit the desired arc-extinguishing performance.

On the other hand, from the viewpoint of suppressing the occurrence of an unpleasant sound such as described above, it is conceivable to fill the housing with a powdered or granular arc-extinguishing material by pressing the powdered or granular arc-extinguishing material. Nevertheless, with such a mode, although occurrences of the unpleasant sound can be suppressed, as a trade-off, when the igniter <NUM> is actuated, it becomes difficult to press the cutoff portion <NUM> cut off from the conductor piece <NUM> and the tip end portion of the rod portion <NUM> into the arc-extinguishing material, and the arc-extinguishing performance may deteriorate. In contrast, according to the fibrous coolant material <NUM> of the present embodiment, there is no such concern. As described above, in the present embodiment, it is possible to realize a breaker device <NUM> that has excellent arc-extinguishing performance and quietness performance, and is unlikely to deteriorate in arc-extinguishing performance over time.

Note that the fibrous coolant material <NUM> with which the arc-extinguishing region R2 of the housing <NUM> is filled is excellent in thermal conductivity, and preferably a fiber material that rapidly removes the thermal energy from the arc generated and the cutoff portion <NUM> when the projectile <NUM> cuts off the cutoff portion <NUM> is used. Examples of such a fiber material include a metal fiber material. Further, steel wool can be suitably used as the metal fiber material constituting the fibrous coolant material <NUM>. However, as long as the cutoff portion <NUM> received in the arc-extinguishing region R2 of the housing <NUM> can be quenched as described above, it is not necessary to employ a metal fiber material as the fibrous coolant material <NUM>.

Note that the breaker device <NUM> in the embodiment described above can adopt various modifications. For example, in the embodiment described above, a mode in which the housing body <NUM> is constituted by the top lid housing portion <NUM>, the central housing portion <NUM>, and the bottom lid housing portion <NUM> is described as an example. However, the mode is not limited thereto. Further, the shape, the size, and the like of the various components constituting the breaker device <NUM> can also be changed as appropriate. For example, in the embodiment described above, a case in which the rod portion <NUM> of the projectile <NUM> has a cylindrical shape is described as an example, but the rod portion <NUM> is not limited thereto and may have, for example, a prismatic shape. In this case, the transverse cross-sectional shape of the small diameter cavity portion 121A of the housing body <NUM> is preferably formed in correspondence with the rod portion <NUM>. Further, in the embodiment described above, a case in which the arc-extinguishing region R2 in the cylindrical space <NUM> of the housing <NUM> is formed including the first arc-extinguishing region R21 and the second arc-extinguishing region R22 having different transverse cross-sectional areas is described as an example, but the mode is not limited thereto. For example, the transverse cross-sectional area of the arc-extinguishing region R2 in the vertical direction may be constant.

Next, an electric circuit interruption test performed on the breaker device <NUM> will be described. <FIG> is a diagram schematically illustrating a testing device used in an electric circuit interruption test. Reference sign <NUM> denotes a power source, reference sign <NUM> denotes an ammeter, and reference sign <NUM> denotes an actuation power source. Further, reference sign <NUM> denotes wiring for forming an electric circuit EC in cooperation with the conductor piece <NUM> of the breaker device <NUM>. Further, reference sign <NUM> denotes wiring for causing an actuation current supplied from the actuation power source <NUM> to flow to the conduction pin <NUM> (refer to <FIG>) of the igniter <NUM> of the breaker device <NUM>.

Next, the steps of the electric circuit interruption test will be described.

(Step <NUM>) As illustrated in <FIG>, the first connecting end portion <NUM> and the second connecting end portion <NUM> of the conductor piece <NUM> of the breaker device <NUM> are respectively connected to the power source <NUM>, the ammeter <NUM>, and the like by the wiring <NUM>, and the igniter <NUM> of the breaker device <NUM> is connected to the actuation power source <NUM> by the wiring <NUM>.

(Step <NUM>) The current from the power source <NUM> is caused to flow to the electric circuit EC.

(Step <NUM>) The actuation power source <NUM> is turned on and the actuation current is applied to the igniter <NUM> of the breaker device <NUM>, thereby actuating the igniter <NUM>.

(Step <NUM>) The power source <NUM> and the actuation power source <NUM> are turned off.

In the interruption test, the value of current flowing to the electric circuit EC was continuously measured by the ammeter <NUM> before and after the actuation current was applied to the igniter <NUM> of the breaker device <NUM> by the actuation power source <NUM>. Note that, in the present interruption test, steel wool (example) was used as the fibrous coolant material <NUM> with which the arc-extinguishing region R2 of the housing <NUM> of the breaker device <NUM> is filled. Further, as a comparative example for comparison with the example, a case where a granular zeolite was disposed in the arc-distinguishing region R2 as the arc-extinguishing material instead of steel wool was used.

Here, a standard type of steel wool available from Nippon Steel Wool Co. (trade name: Bonstar, standard wire diameter: φ0. <NUM>) was used. Further, in the comparative example, a granular zeolite available from Tosoh Corporation (trade name: Zeoram) was used.

<FIG> shows graphs of results of the electric circuit interruption test. The test results of the example and the comparative example are shown in the upper half and the lower half, respectively. In each graph, the vertical axis indicates the current value and the horizontal axis indicates time. Time T0 indicates the time when the actuation power source <NUM> was turned on and the actuation current was applied to the igniter <NUM>.

The example using steel wool as the arc-extinguishing material (upper half of <FIG> ) and the comparative example using a granular zeolite as the arc-extinguishing material (lower half of <FIG> ) both rapidly reduced the value of current flowing through the electric circuit EC to zero after actuation of the igniter <NUM> at time T0. This is conceivably due to the arc being quickly extinguished by the arc-extinguishing materials used in the example and the comparative example. ΔT1 shown in the upper half of <FIG> indicates the time required from time TO until the value of current flowing through the electric circuit EC reached zero (hereinafter referred to as "arc-extinguishing time") in the example. Further, ΔT2 shown in the lower half of <FIG> indicates the arc-extinguishing time in the comparative example.

Here, it was found that the arc-extinguishing time ΔT1 in the example is slightly shorter than the arc-extinguishing time ΔT2 in the comparative example. Accordingly, based on the results of the present interruption test, it was confirmed that the example using steel wool as the arc-extinguishing material has at least the same or higher arc-extinguishing performance as that of the comparative example using the granular zeolite as the arc-extinguishing material. Note that, as described above, an arc-extinguishing material having a fibrous form such as steel wool has a different technical effect that cannot be obtained by the granular or powdered arc-extinguishing material.

Claim 1:
An electric circuit breaker device (<NUM>) comprising:
an igniter (<NUM>) provided to a housing (<NUM>);
a projectile (<NUM>) disposed in a cylindrical space (<NUM>) formed in the housing (<NUM>), the projectile (<NUM>) being movable in the cylindrical space (<NUM>) by energy received from the igniter (<NUM>); and
a conductor piece (<NUM>) that is provided to the housing (<NUM>), forms a portion of an electric circuit, includes a cutoff portion (<NUM>) to be cut off by the projectile (<NUM>) in a portion thereof, and is disposed with the cutoff portion (<NUM>) crossing the cylindrical space (<NUM>);
characterized in that
the electric circuit breaker device (<NUM>) further comprises:
an arc-extinguishing region (R2) positioned within the cylindrical space (<NUM>), on a side opposite to the projectile (<NUM>) prior to actuation of the igniter (<NUM>) with the cutoff portion (<NUM>) interposed between the arc-extinguishing region (R2) and the projectile (<NUM>), and configured to receive the cutoff portion (<NUM>) cut off by the projectile (<NUM>); and
a coolant material (<NUM>) having a fibrous form and disposed in the arc-extinguishing region (R2), so that at the moment when the cutoff portion (<NUM>) of the conductor piece (<NUM>) is cut off by the projectile (<NUM>) the cutoff portion (<NUM>) can be instantaneously buried in the coolant material (<NUM>) in the arc-extinguishing region (R2) and quenched by the coolant material (<NUM>), wherein
the coolant material (<NUM>) is a coolant material that removes thermal energy of the arc generated when the projectile (<NUM>) cut off the cutoff portion (<NUM>), and the coolant material (<NUM>) is formed from a metal fiber material.