CN117897792A

CN117897792A - Protection device

Info

Publication number: CN117897792A
Application number: CN202280058066.9A
Authority: CN
Inventors: 米田吉弘
Original assignee: Dexerials Corp
Current assignee: Dexerials Corp
Priority date: 2021-09-03
Filing date: 2022-08-30
Publication date: 2024-04-16

Abstract

The device comprises: the fuse element (50), the insulating case (260), the first terminal (91), and the second terminal (92) further have: an insulating member (60) which is disposed in a state of approaching or contacting the fuse element (50) and has an opening or a separation portion formed therein; a shielding member (220) movable so as to intercept the fuse element (50); a pressing unit (230) that presses the shielding member (220); a locking member (270) that is locked between the insulating housing (260) and the shielding member (220) and suppresses movement of the shielding member (220); a heating element (80) that heats and softens the locking member (270) or the fixing member; and a power supply member (90), wherein the insulating housing (260) also accommodates the insulating member (60), the shielding member (220), the pressing unit (230), the locking member (270), the heating element (80), and a part of the power supply member (90).

Description

Protection device

Technical Field

The present invention relates to a protection device.

The present application claims priority based on japanese patent application nos. 2021-144287 of the japanese application at 9/3 and 2022 at 7/29 of the japanese application, and the contents of which are incorporated herein by reference, in japanese patent application nos. 2022-121949 of the japanese application.

Background

Conventionally, there is a fuse element that generates heat and blows when a rated current is passed through a current path, and opens the current path. Protection devices (fuse devices) including fuse elements are used in a wide range of fields, such as home appliances and electric vehicles.

For example, lithium ion batteries are used in a wide range of applications from mobile equipment applications to Electric Vehicles (EVs), storage batteries, and the like, and the capacity thereof is increasing. With the increase in capacity of lithium ion batteries, the voltage is a high-voltage standard of several hundred volts, and a large current standard of several hundred to several thousand amperes is also required for the current.

For example, patent document 1 discloses a fuse element as a fuse element mainly used for an automobile circuit or the like, the fuse element including: two elements connected between the terminal portions at both ends and a fuse portion provided at a substantially central portion of the elements. Patent document 1 describes a fuse in which a pair of fuse elements is housed in a case, and an arc extinguishing material is enclosed between the fuse elements and the case.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open publication No. 2017-004634

Disclosure of Invention

Problems to be solved by the invention

In a protection device provided in a high-voltage and high-current path, arcing is likely to occur when a fuse element is blown. If a large-scale arc discharge occurs, the insulating case accommodating the fuse element may be broken. Therefore, a low-resistance and high-melting-point metal such as copper is used as a material of the fuse element to suppress the occurrence of arc discharge. In addition, a strong and highly heat-resistant material such as ceramic is used as a material of the insulating case, and the size of the insulating case is further increased.

In addition, the current fuse of high voltage and large current (more than 100V/100A) has been opened only by overcurrent, and does not have an opening function based on an opening signal.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a protection device which is capable of preventing large-scale arcing from occurring when a fuse element is blown, reducing the size and weight of an insulating case, and having both overcurrent breaking against high voltage and large current and breaking functions based on a breaking signal.

Solution for solving the problem

In order to solve the above problems, the present invention provides the following means.

[ solution 1 of the invention ]

A protection device, having: the fuse element, the insulating housing that holds the fuse element, the first terminal and the second terminal, still have: an insulating member disposed in a state of approaching or contacting the fuse element, and having an opening or a separation portion formed therein; a shielding member movable in an insertion direction into the opening or the separation portion of the insulating member so as to intercept the fuse element; a pressing unit that presses the shielding member in an insertion direction of the shielding member; a locking member that is locked between the insulating housing and the shielding member, and suppresses movement of the shielding member; a heating element that heats and softens the locking member or a fixing member that fixes the locking member; and a power feeding member for applying a current to the heating element, wherein the fuse element has a first end portion and a second end portion which are opposed to each other, one end portion of the first terminal is connected to the first end portion, the other end portion is exposed to the outside from the insulating case, one end portion of the second terminal is connected to the second end portion, the other end portion is exposed to the outside from the insulating case, and the insulating case further accommodates the insulating member, the shielding member, the pressing unit, the locking member, the heating element, and a part of the power feeding member.

[ solution 2 of the invention ]

The protection device according to claim 1, wherein the heat generating body generates heat, the locking member or the fixing member softens, and thereby the shielding member moves while separating the locking member or the fixing member by a pressing force of the pressing unit, and further, the shielding member moves at the opening portion or the separating portion of the insulating member to cut off the fuse element, thereby cutting off the energization of the fuse element.

[ solution 3 of the invention ]

The protection device according to claim 2, wherein the shielding member cuts the fuse element, and portions of the fuse element to be cut are shielded from each other in an energizing direction of the fuse element.

[ solution 4 of the invention ]

The protection device according to any one of claims 1 to 3, wherein the pressing unit is a spring.

[ solution 5 of the invention ]

The protective device according to any one of claims 1 to 4, wherein at least one of the insulating member, the shielding member, and the insulating case is formed of a material having a tracking resistance index CTI of 500V or more.

[ solution 6 of the invention ]

The protective device according to any one of claims 1 to 5, wherein at least one of the insulating member, the shielding member, and the insulating case is formed of one resin material selected from the group consisting of polyamide-based resin and fluorine-based resin.

[ solution 7 of the invention ]

The protective device according to any one of claims 1 to 6, wherein the fuse element is a laminate including a low-melting-point metal layer containing tin and a high-melting-point metal layer containing silver or copper.

[ solution 8 of the invention ]

The protective device according to claim 7, wherein the fuse element is a laminate having two or more high-melting-point metal layers and one or more low-melting-point metal layers, and the low-melting-point metal layers are disposed between the high-melting-point metal layers.

[ solution 9 of the invention ]

The protective device according to any one of claims 1 to 8, wherein the fuse element is a single layer body containing silver or copper.

[ solution 10 of the invention ]

The protection device according to any one of claims 1 to 9, wherein the fuse element has a fusing portion between the first end portion and the second end portion, and a cross-sectional area of the fusing portion in the current flowing direction is smaller than a cross-sectional area of the first end portion and the second end portion in the current flowing direction from the first end portion toward the second end portion.

[ solution 11 of the invention ]

The protection device according to any one of claims 1 to 10, wherein the fuse element has a first fusible conductor and a second fusible conductor having a melting point lower than that of the first fusible conductor, the first fusible conductor and the second fusible conductor being connected in series in energization.

[ solution 12 of the invention ]

The protective device according to claim 11, wherein the second fusible conductor is disposed between two of the first fusible conductors.

[ solution 13 of the invention ]

The protective device according to claim 11 or 12, wherein the shielding member moves by heat generation of the heat generating body, and the second fusible conductor is cut off.

[ solution of the invention 14 ]

The protection device according to any one of claims 1 to 13, wherein the insulating housing has an inner bottom surface arranged in a state of approaching or contacting an opposite side of the fuse element from the shielding member, the inner bottom surface having a groove extending along the opening portion or the separation portion of the insulating member, and a tip end of the shielding member in an insertion direction is insertable into the groove.

[ solution 15 of the invention ]

The protection device according to any one of claims 1 to 14, wherein the protection device has: a plurality of the fuse elements stacked in parallel in a direction perpendicular to a surface of the plate-shaped fuse element; and a plurality of insulating members disposed in contact with or in proximity to each other between the plurality of fuse elements, wherein the opening portions or the separation portions of the plurality of insulating members overlap each other when viewed in a vertical direction, and the shielding member is movable in all of the opening portions or the separation portions.

[ solution 16 of the invention ]

The protection device according to claim 15, wherein the plurality of insulating members include the insulating member disposed outside of the outermost layer on the shielding member side of the plurality of fuse elements, the insulating housing has an inner bottom surface disposed in a state of approaching or contacting the outside of the outermost layer on the opposite side of the shielding member of the plurality of fuse elements, the inner bottom surface has a groove extending along the opening portion or the separation portion of the insulating member, and the shielding member is movable in all of the opening portions or the separation portions and the groove.

[ solution 17 of the invention ]

The protection device according to any one of claims 1 to 16, wherein the protection device has: a plurality of the fuse elements stacked in parallel in a direction perpendicular to a surface of the plate-shaped fuse element; and a plurality of insulating members disposed in contact with or in proximity to each other and the outside of the plurality of fuse elements, wherein the opening portions or the separation portions of the plurality of insulating members overlap each other when viewed in a vertical direction, and the shielding member is movable in all of the opening portions or the separation portions.

[ solution of the invention 18 ]

The protection device according to any one of claims 1 to 17, wherein the insulating case has at least two holding members arranged on both sides of the plate-shaped fuse element in a direction perpendicular to a face of the fuse element, and one or both of the two holding members is integrally formed with the insulating member.

[ solution 19 of the invention ]

The protective device according to any one of claims 1 to 18, wherein the locking member is sandwiched between the insulating case and the shielding member in an insertion direction of the shielding member, and is locked such that a dimension of the locking member in an insertion direction is larger than a dimension of the locking member in a direction from the heating element toward the locking member, as viewed in a width direction orthogonal to a current-carrying direction of the fuse element and the insertion direction of the shielding member, or as viewed in the current-carrying direction.

[ solution of the invention 20 ]

The protective device according to any one of claims 1 to 19, wherein the shielding member has a first step portion oriented in an insertion direction of the shielding member, the insulating case has a second step portion oriented on a side opposite to the first step portion in the insertion direction, and a pair of end surfaces of the locking member oriented in the insertion direction are sandwiched by the first step portion and the second step portion, the first step portion and the second step portion not overlapping each other as viewed in the insertion direction.

Effects of the invention

According to the present invention, it is possible to provide a protection device which is less likely to cause large-scale arc discharge when a fuse element is blown, which is small in size and light in weight, and which has both an overcurrent breaking function against a high voltage and a large current and a breaking function based on a breaking signal.

Drawings

Fig. 1 is a perspective view of a protection device according to a first reference example, which is different from the present invention, which is a part of the technical idea.

Fig. 2 is a perspective view with a portion removed in a manner visible inside the protection device shown in fig. 1.

Fig. 3 is an exploded perspective view of the protection device shown in fig. 1.

Fig. 4A is a plan view schematically showing one fusible conductor piece constituting the fuse element laminate, and the first and second terminals.

Fig. 4B is a plan view schematically showing the fuse element laminate, the second insulating member, the first terminal, and the second terminal.

Fig. 4C is a cross-sectional view taken along line X-X' of the top view shown in fig. 4B.

Fig. 5 is a cross-sectional view taken along line V-V' of fig. 1, showing the vicinity of the locking member in an enlarged view.

Fig. 6 is a sectional view of the protection device in a state where the shielding member cuts off and lowers the fuse element to the bottom.

Fig. 7 is a cross-sectional view of a protection device according to a modification of the locking member, and shows the vicinity of the locking member in an enlarged view.

Fig. 8A shows an example of the structure of the heating element, and shows a top plan view.

Fig. 8B shows an example of the structure of the heating element, and shows a top view of the upper surface of the insulating substrate before printing.

Fig. 8C shows an example of the structure of the heating element, and shows a top plan view of the resistive layer after printing.

Fig. 8D shows an example of the structure of the heating element, and shows a top plan view of the insulating layer after printing.

Fig. 8E shows an example of the structure of the heating element, and shows a top plan view of the electrode layer after printing.

Fig. 8F shows an example of the structure of the heating element, and shows a top view of the lower surface.

Fig. 9A is a perspective view of a protection device for explaining a method of pulling out a power feeding member for feeding power to a heating element, and shows a case where two heating elements are connected in series.

Fig. 9B is a perspective view of a protection device for explaining a method of pulling out a power feeding member for feeding power to a heating element, and shows a case where two heating elements are connected in parallel.

Fig. 10A is a schematic diagram of a modification of the first reference example, and shows a perspective view of a holding member 10BB as a modification of the holding member 10B.

Fig. 10B is a schematic diagram of a modification of the first reference example, and shows a perspective view of a holding member 10BB as a modification of the holding member 10B, and a first insulating member 61A and a second insulating member 61B as a modification of the first insulating member 60A and the second insulating member 60B.

Fig. 11A is a perspective view of a second insulating member 61B of a modification.

Fig. 11B is a perspective view of a first insulating member 61A of a modification.

Fig. 12A is a perspective view schematically showing a portion removed in such a manner that the inside of the protection device of the second reference example is visible.

Fig. 12B is a lower perspective view of the masking member of fig. 12A.

Fig. 13 is a sectional view corresponding to fig. 5 of the protection device of the second reference example.

Fig. 14 is a sectional view of the protection device in a state where the shielding member cuts off and lowers the fuse element to the bottom.

Fig. 15 is a perspective view schematically showing a state in which the fuse element laminate, the first terminal, and the second terminal are provided on the first holding member.

Fig. 16 is a cross-sectional view (cross-sectional view perpendicular to the width direction) showing the protection device of the embodiment.

Fig. 17 is a cross-sectional view (cross-sectional view perpendicular to the width direction) showing the protection device according to the embodiment, and shows a state in which the shielding member cuts off and lowers the fuse element to the bottom.

Fig. 18 is a cross-sectional view (cross-sectional view perpendicular to the width direction) schematically showing a part of the protection device of the embodiment.

Fig. 19 is a cross-sectional view (cross-sectional view perpendicular to the width direction) schematically showing a part of the protection device according to the embodiment, and shows a state after the shielding member moves downward.

Fig. 20 is a cross-sectional view (cross-sectional view perpendicular to the width direction) schematically showing a part of a protection device according to a modification of the embodiment.

Fig. 21 is a cross-sectional view (cross-sectional view perpendicular to the width direction) schematically showing a part of a protection device according to a modification of the embodiment, and shows a state after the shielding member moves downward.

Fig. 22 is a cross-sectional view (X-Z cross-sectional view) showing a part of a protection device according to a modification of the embodiment.

Fig. 23 is a schematic diagram of a fuse element according to a modification of the embodiment, and is a plan view corresponding to fig. 4A.

Detailed Description

Hereinafter, reference examples, which differ from the present invention in part in technical idea, will be described in detail with reference to the accompanying drawings as appropriate. In the drawings used in the following description, for the sake of easy understanding of the features, the portions to be the features may be shown enlarged, and the dimensional ratios of the respective constituent elements may be different from actual ones. The materials, dimensions, and the like shown in the following description are examples, and the present invention is not limited thereto, and may be implemented with appropriate modifications within the scope of the effects of the present invention.

(protection device (first reference example))

Fig. 1 to 5 are schematic views showing a protection device according to a first reference example. In the drawings used in the following description, the direction indicated by X is the current-carrying direction of the fuse element. The direction indicated by Y is a direction orthogonal to the X direction, and is also referred to as a width direction. In this reference example, one side in the width direction (Y direction) corresponds to the-Y side, and the other side corresponds to the +y side. However, the present invention is not limited thereto, and one side in the width direction may be referred to as the +y side, and the other side in the width direction may be referred to as the-Y side. The direction indicated by Z is a direction orthogonal to the X direction and the Y direction, and is also referred to as a thickness direction. The thickness direction may be in other words the up-down direction. The upper side in the up-down direction (Z direction) corresponds to the +z side, and the lower side corresponds to the-Z side.

In the present reference example, the upper and lower parts refer to only names for describing the relative positional relationships of the parts, and the actual arrangement relationship may be other than the arrangement relationship shown by these names.

Fig. 1 is a perspective view schematically showing a protection device of a first reference example. Fig. 2 is a perspective view with a portion removed in a manner visible inside the protection device shown in fig. 1. Fig. 3 is an exploded perspective view schematically showing the protection device shown in fig. 1. Fig. 4A is a plan view schematically showing one fusible conductor piece constituting the fuse element laminate, and the first and second terminals. Fig. 4B is a plan view schematically showing the fuse element laminate, the second insulating member, the first terminal, and the second terminal. Fig. 4C is a cross-sectional view taken along line X-X' of the top view shown in fig. 4B. Fig. 5 is a cross-sectional view taken along line V-V' of fig. 1, showing the vicinity of the locking member in an enlarged view.

The protection device 100 shown in fig. 1 to 5 includes: the insulating case 10, the fuse element laminate 40, the first insulating member 60A, the second insulating member 60B, the shielding member 20, the pressing unit 30, the locking member 70, the heating element 80, the power feeding members 90A, 90B, the first terminal 91, and the second terminal 92. The first insulating member 60A and the second insulating member 60B may be only the insulating members 60A and 60B.

In the protection device 100 of the present reference example, the current-carrying direction is a direction (X direction) in which electricity flows when in use, that is, a direction corresponding to the connection between the first terminal 91 and the second terminal 92. In the current flowing direction, the direction from the first terminal 91 toward the second terminal 92 may be referred to as the second terminal 92 side (-X side), and the direction from the second terminal 92 toward the first terminal 91 may be referred to as the first terminal 91 side (+x side). The cross-sectional area in the current-carrying direction is the area of the surface (Y-Z surface) in the direction perpendicular to the current-carrying direction.

In the protection device 100 shown in fig. 1 to 5, an example is shown in which the first insulating member 60A and the second insulating member 60B are members having different configurations, and the first insulating member 60A and the second insulating member 60B may have the same configuration.

The protection device 100 of the present reference example has an overcurrent opening and an active opening as a mechanism for opening a current path. In the overcurrent interruption, when an overcurrent exceeding a rated current flows through the fusible conductor piece 50 (see fig. 4C), the fusible conductor piece 50 fuses to interrupt the current path. In the case where an abnormality other than an overcurrent occurs during the active disconnection, the current is applied to the heat generating element 80 to melt the locking member 70 that suppresses the movement of the shielding member 20, so that the shielding member 20 to which the pressing force is applied downward by the pressing unit 30 is moved, and the fuse element 50 is cut off, thereby disconnecting the current path.

(insulating housing)

The insulating housing 10 has a substantially elliptical columnar shape (the cross section of the Y-Z plane is elliptical at any position in the X direction). The insulating housing 10 is constituted by a cover 10A and a holding member 10B.

The cover 10A has an elliptical cylindrical shape with both ends open. The inner edge of the opening of the cover 10A is a chamfered inclined surface 21. The central portion of the cover 10A is an accommodation portion 22 accommodating the holding member 10B.

The holding member 10B is composed of a first holding member 10Ba arranged on the lower side in the Z direction and a second holding member 10Bb arranged on the upper side in the Z direction.

As shown in fig. 3, terminal mounting surfaces 111 are provided at both ends (first end 10Baa, second end 10 Bab) of the first holding member 10Ba in the current-carrying direction (X direction).

As shown in fig. 3, the power feeding member mounting surface 12 is provided at both ends (the first end 10Baa and the second end 10 Bab) of the first holding member 10 Ba. The position (height) of the power feeding member mounting surface 12 in the Z direction is located at substantially the same height as the position (height) of the heating element 80, thereby shortening the pull-around distance of the power feeding member 90.

An internal pressure buffer space 15 is formed inside the holding member 10B (see fig. 5 and 6). The internal pressure buffer space 15 has an effect of suppressing: the internal pressure of the protection device 100 increases sharply due to gas generated by arc discharge generated when the fuse element stack 40 is blown.

The cover 10A and the holding member 10B are preferably formed of a material having a tracking index CTI (resistance to damage by tracking (carbonized conductive path)) of 500V or more.

The tracking index CTI can be obtained by a test based on IEC 60112.

As the material of the cover 10A and the holding member 10B, a resin material may be used.

The resin material has smaller heat capacity and lower melting point than the ceramic material. Therefore, if a resin material is used as the material of the holding member 10B, there is a characteristic of reducing arc discharge caused by vaporization cooling (ablation); when the molten and scattered metal particles adhere to the holding member 10B, the surface of the holding member 10B is deformed or the adhering matter is aggregated, and the metal particles are sparse and the characteristics of the conductive path are not easily formed are preferable.

As the resin material, for example, polyamide resin or fluorine resin can be used. The polyamide resin may be aliphatic polyamide or semi-aromatic polyamide. Examples of the aliphatic polyamide include: nylon 4, nylon 6, nylon 46, nylon 66. Examples of the semiaromatic polyamide include: nylon 6T, nylon 9T, polyphthalamide (PPA) resins. As an example of the fluorine-based resin, polytetrafluoroethylene is given. In addition, polyamide resins and fluorine resins have high heat resistance and are not easily burned. In particular, aliphatic polyamides do not readily form graphite even when burned. Therefore, by forming the cover 10A and the holding member 10B using the aliphatic polyamide, it is possible to more reliably prevent the formation of a new current path due to graphite generated by arc discharge when the fuse element laminate 40 is blown.

(fuse element laminate)

The fuse element laminate has: a plurality of fusible conductor pieces arranged in parallel in the thickness direction; and a plurality of first insulating members disposed in a state of being close to or in contact with each of the plurality of fusible conductor pieces and an outer side of the fusible conductor piece disposed at the lowermost portion among the plurality of fusible conductor pieces, and formed with a first opening portion or a first separation portion. The plurality of fusible conductor pieces may be collectively referred to as a fuse element. The fuse element laminate is composed of a fuse element and a first insulating member.

The fuse element laminate 40 has six fusible conductor pieces 50a, 50b, 50c, 50d, 50e, 50f arranged in parallel in the thickness direction (Z direction). First insulating members 60Ab, 60Ac, 60Ad, 60Ae, 60Af are disposed between the fusible conductor sheets 50a to 50f. The first insulating members 60Aa to 60Af are arranged in a state of being close to or in contact with the respective fusible conductor sheets 50a to 50f. The state of proximity is preferably a state in which the distance between the first insulating members 60Ab to 60Af and the fusible conductor chips 50a to 50f is 0.5mm or less, more preferably 0.2mm or less.

Further, a first insulating member 60Aa is disposed outside the lowermost fusible conductor piece 50a among the fusible conductor pieces 50a to 50f. Further, the second insulating member 60B is disposed outside the uppermost fusible conductor piece 50f among the fusible conductor pieces 50a to 50f. The width (length in the Y direction) of the fusible conductor sheets 50a to 50f is narrower than the widths of the first insulating members 60Aa to 60Af and the second insulating member 60B.

The fuse element laminate 40 is an example in which a plurality of fusible conductor pieces is six, but the number is not limited to six and may be a plurality.

Each of the fusible conductor pieces 50a to 50f has a first end portion 51 and a second end portion 52 which are opposed to each other, and a fusing portion 53 which is located between the first end portion 51 and the second end portion 52. The first ends 51 of the three fusible conductor pieces 50a to 50c from below among the fusible conductor pieces 50a to 50f arranged in parallel in the thickness direction are connected to the lower surface of the first terminal 91, and the first ends 51 of the three fusible conductor pieces 50d to 50f from above are connected to the upper surface of the first terminal 91. The second ends 52 of the three fusible conductor pieces 50a to 50c from below among the fusible conductor pieces 50a to 50f are connected to the lower surface of the second terminal 92, and the second ends 52 of the three fusible conductor pieces 50d to 50f from above are connected to the upper surface of the second terminal 92. The connection positions of the fusible conductor sheets 50a to 50f and the first terminal 91 and the second terminal 92 are not limited to this. For example, all of the first ends 51 of the fusible conductor chips 50a to 50f may be connected to the upper surface of the first terminal 91 or may be connected to the lower surface of the first terminal 91. All of the second end portions 52 of the fusible conductor sheets 50a to 50f may be connected to the upper surface of the second terminal 92 or may be connected to the lower surface of the second terminal 92.

Each of the fusible conductor sheets 50a to 50f may be a laminate including a low-melting metal layer and a high-melting metal layer, or may be a single-layer. The laminate including the low-melting point metal layer and the high-melting point metal layer may have a structure in which the periphery of the low-melting point metal layer is covered with the high-melting point metal layer.

The low-melting-point metal layer of the laminate contains Sn. The low-melting point metal layer may be a simple substance of Sn or an Sn alloy. The Sn alloy is an alloy containing Sn as a main component. The Sn alloy is an alloy having the largest Sn content in the metals contained in the alloy. Examples of Sn alloys include: sn-Bi alloy, in-Sn alloy, sn-Ag-Cu alloy. The high melting point metal layer contains Ag or Cu. The high-melting-point metal layer can be an Ag simple substance, a Cu simple substance, an Ag alloy or a Cu alloy. The Ag alloy is an alloy having the largest content of Ag in the metal contained in the alloy, and the Cu alloy is an alloy having the largest content of Cu in the metal contained in the alloy. The laminate may have a two-layer structure of a low-melting-point metal layer and a high-melting-point metal layer, or may have a multi-layer structure of three or more layers including two or more high-melting-point metal layers, one or more low-melting-point metal layers, and the low-melting-point metal layers disposed between the high-melting-point metal layers.

In the case of a single layer, ag or Cu is contained. The single layer body can be an Ag simple substance, a Cu simple substance, an Ag alloy or a Cu alloy.

The fusible conductor sheets 50a to 50f may have through holes 54 (54 a, 54b, 54 c) in the fuse portion 53. In the example shown in the figure, the number of through holes is three, but there is no limitation on the number. By having the through hole 54, the cross-sectional area of the fusing part 53 is smaller than the cross-sectional areas of the first end part 51 and the second end part 52. Since the cross-sectional area of the fusing part 53 is small, when a large current exceeding the rated value flows through the fusible conductor pieces 50a to 50f, the amount of heat generated by the fusing part 53 increases, and the fusing part 53 becomes a fusing part and is easily fused. The structure of the fusing part 53 to be fused more easily than the first end part 51 and the second end part 52 is not limited to the through hole, and may be a structure of narrowing the width, locally thinning the thickness, or the like. The shape of the slit may be a dotted hole.

In addition, the fusing part 53 configured to be easily fused out of the fusible conductor pieces 50a to 50f is easily cut by the convex part 20a of the shielding member 20.

The thickness of the fusible conductor pieces 50a to 50f is set to a thickness that can be fused by an overcurrent and physically cut by the shielding member 20. The specific thickness depends on the material and number (number of sheets) of the fusible conductor pieces 50a to 50f and the pressing force (stress) of the pressing unit 30, and may be in the range of 0.01mm to 0.1mm based on the case where the fusible conductor pieces 50a to 50f are copper foils, for example. The fusible conductor pieces 50a to 50f may be in the range of 0.1mm to 1.0mm based on the case where the foil is formed by plating the periphery of an alloy containing Sn as a main component with Ag.

Each of the first insulating members 60Aa to 60Af is composed of a first insulating sheet 63a and a second insulating sheet 63b facing each other with a gap (first separation portion) 64 therebetween. The second insulating member 60B is also composed of a third insulating sheet 66a and a fourth insulating sheet 66B facing each other with a gap (second separation portion) 65 therebetween. In the illustrated example, the gaps 64 and 65 between the first insulating members 60Aa to 60Af and the second insulating member 60B are separate portions (first separate portion and second separate portion) that separate into two members, or may be openings (first opening and second opening) through which the convex portion 20a of the shielding member 20 can move (pass). The above two members are the first insulating sheet 63a and the second insulating sheet 63b or the third insulating sheet 66a and the fourth insulating sheet 66b. The first and second separating portions 64 and 65 may be only the separating portions 64 and 65. The first opening and the second opening may be in other words, only the openings (see the first opening 64A and the second opening 65A in the modification described later).

The first insulating sheet 63a and the second insulating sheet 63b have, on both end sides in the Y direction: the vent hole 67 is used for effectively releasing the pressure rise caused by the arc discharge generated during the disconnection of the fuse element to the pressing unit accommodating space of the insulating housing. In the illustrated example, the first insulating sheet 63a and the second insulating sheet 63b each have three ventilation holes 67 on both end sides in the Y direction, but there is no limitation on the number.

The rising pressure generated by the arc discharge is efficiently released to the space of the insulating housing 10 accommodating the pressing unit 30 through the vent hole 67 via gaps (not shown) provided at four corners between the pressing unit supporting portion 20b and the second holding member 10 Bb. As a result, the shielding operation of the shielding member 20 is smoothly performed, and damage to the first insulating members 60Aa to 60Af and the second insulating member 60B is prevented.

The gaps 64 and 65 are located at positions facing the fuse portion 53 disposed between the first end 51 and the second end 52 of the fusible conductor sheets 50a to 50 f. That is, the first insulating members 60Aa to 60Af and the second insulating member 60B are separated at positions facing the fuse portions 53 of the fusible conductor sheets 50a to 50 f.

The first insulating members 60Aa to 60Af and the second insulating member 60B are preferably formed of a material having a tracking resistance index CTI of 500V or more.

As the material of the first insulating members 60Aa to 60Af and the second insulating member 60B, a resin material may be used. An example of the resin material is the same as the case of the cover 10A and the holding member 10B.

The fuse element laminate 40 can be manufactured as follows, for example.

The fusible conductor pieces 50a to 50f and the first insulating members 60Ab to 60Af are alternately laminated in the thickness direction on the first insulating member 60Aa using a jig having positioning recesses corresponding to protruding portions provided on the first insulating members 60Aa to 60Af and the second insulating member 60B and positioning fixing portions of the first terminal 91 and the second terminal 92, and the second insulating member 60B is disposed on the upper surface of the fusible conductor piece 50f disposed at the uppermost portion, thereby obtaining a laminated body.

(screening member)

The shielding member 20 has: the convex portion 20a facing the fuse element laminate 40; and a pressing unit supporting portion 20b having a concave portion 20ba that accommodates and supports the lower portion of the pressing unit 30.

The shielding member 20 is restrained from moving downward by the locking member 70 in a state where a pressing force of the pressing unit 30 is applied downward. Therefore, when the locking member 70 is heated by the heat generation of the heat generating element 80 and softened at a temperature equal to or higher than the softening temperature, the shielding member 20 can move downward. At this time, the softened locking member 70 is physically cut by the shielding member 20, thermally fused, or physically cut by the shielding member 20 and thermally fused in combination, depending on the kind of material, heating condition, and the like thereof.

When the downward movement inhibition of the shielding member 20 by the locking member 70 is released, the shielding member moves downward, and the fusible conductor pieces 50a to 50f are physically cut.

In the shielding member 20, the tip 20aa of the convex portion 20a is sharp, and the fusible conductor pieces 50a to 50f are easily cut.

Fig. 6 shows a cross-sectional view of the protection device in a state where the shielding member 20 moves in the gaps 64 and 65 of the fuse element laminate 40, and the fusible conductor pieces 50a, 50b, 50c, 50d, 50e, and 50f are cut by the convex portions 20a, so that the shielding member 20 is lowered to the bottom.

The shielding member 20 moves down in the gaps 65, 64 of the fuse element laminate 40, and the fusible conductor pieces 50f, 50e, 50d, 50c, 50b, 50a are cut in order by the convex portion 20a of the shielding member 20. In this way, the cut surfaces are shielded and insulated by the convex portions 20a, and the current-carrying path through each fusible conductor piece is physically and reliably disconnected. Thereby, the arc discharge is rapidly extinguished (extinguished).

In a state where the shielding member 20 moves and descends downward in the gaps 65 and 64 of the fuse element laminate 40, the pressing unit support portion 20B of the shielding member 20 presses the fuse element laminate 40 from the second insulating member 60B, and the fusible conductor pieces are in close contact with the first insulating members 60Aa to 60Af and the second insulating member 60B. Therefore, there is no space between them where arc discharge can continue, and the arc discharge is reliably extinguished.

The thickness (length in the X direction) of the convex portion 20a is smaller than the widths in the X direction of the gaps 64, 65 between the first insulating members 60Aa to 60Af and the second insulating member 60B. With this configuration, the convex portion 20a can move downward in the Z direction in the gaps 64 and 65.

For example, in the case where the fusible conductor sheets 50a to 50f are copper foils, the difference between the thickness of the convex portion 20a and the width of the gaps 64 and 65 in the X direction may be, for example, 0.05 to 1.0mm, and preferably 0.2 to 0.4mm. If the thickness is 0.05mm or more, even if the ends of the fusible conductor pieces 50a to 50f in the case where the minimum thickness after cutting is 0.01mm enter the gaps between the first insulating members 60Aa to 60Af and the second insulating member 60B and the convex portion 20a, the movement of the convex portion 20a is smooth, and the arc discharge can be extinguished more rapidly and reliably. The reason for this is that: when the difference is 0.05mm or more, the convex portion 20a is less likely to be caught. If the difference is 1.0mm or less, the gaps 64 and 65 function as guide rails for moving the convex portion 20 a. Therefore, the position of the convex portion 20a that moves when the fusible conductor pieces 50a to 50f are fused is prevented from being shifted, and the arc discharge is extinguished more rapidly and reliably. When the fusible conductor pieces 50a to 50f are foils formed by plating the surroundings of an alloy containing Sn as a main component with Ag, the difference between the thickness of the convex portion 20a and the width of the gaps 64 and 65 in the X direction may be, for example, 0.2 to 2.5mm, and preferably 0.22 to 2.2mm.

The width (length in the Y direction) of the convex portion 20a is wider than the width of the fusible conductor pieces 50a to 50f of the fuse element laminate 40. With this configuration, the convex portion 20a can cut the fusible conductor pieces 50a to 50 f.

The length L of the convex portion 20a in the Z direction has the following length: when the convex portion 20a is lowered downward in the Z direction, the tip 20Aa of the convex portion 20a can reach below the first insulating member 60Aa arranged at the lowermost portion in the Z direction among the first insulating members 60Aa to 60 Af. When the convex portion 20a is lowered below the first insulating member 60Aa disposed at the lowermost portion, it is inserted into the insertion hole 14 formed in the inner bottom surface 13 of the holding member 10 Ba.

With this configuration, the convex portion 20a can cut the fusible conductor pieces 50a to 50 f.

(pressing unit)

The pressing unit 30 is accommodated in the recess 20ba of the shielding member 20 in a state of pressing the shielding member 20 downward in the Z direction.

As the pressing means 30, for example, a known means capable of imparting elastic force such as a spring or rubber can be used.

In the protection device 100, a spring is used as the pressing unit 30. The spring (pressing unit) 30 is held in a contracted state in the concave portion 20ba of the shielding member 20.

As a material used for the spring of the pressing unit 30, a known material may be used.

As the spring that can be used as the pressing means 30, a cylindrical spring or a conical spring may be used. If a conical spring is used, the contraction length can be shortened, so that the height at the time of pressing can be suppressed, and the protection device can be miniaturized. Moreover, a plurality of conical springs may be stacked to enhance the stress.

When a conical spring is used as the pressing means 30, the side having the smaller outer diameter may be disposed toward the fuse portion (cutting portion) 53 of each of the fusible conductor pieces 50a to 50f, or the side having the larger outer diameter may be disposed toward the fuse portion 53 of each of the fusible conductor pieces 50a to 50 f.

When a conical spring is used as the pressing means 30, the side with the smaller outer diameter may be disposed toward the fusing portion (cutting portion) 53 side of each of the fusible conductor pieces 50a to 50 f. In this way, for example, when the spring is made of a conductive material such as metal, the continuation of arc discharge generated when the fuse portion 53 of each fusible conductor piece 50a to 50f is cut can be more effectively suppressed. The reason for this is that: it is easy to ensure the distance between the arc discharge generating position and the conductive material forming the spring.

In the case where a conical spring is used as the pressing means 30 and the side having the larger outer diameter is disposed toward the fuse portion 53 side of each of the fusible conductor pieces 50a to 50f, it is preferable that the elastic force be applied more uniformly from the pressing means 30 to the shielding member 20.

(locking Member)

The locking member 70 bridges the gap 65 of the second insulating member 60B, and suppresses movement of the shielding member 20.

The protection device 100 includes three locking members 70 (70A, 70B, 70C), but is not limited to three.

The locking member 70A is placed (inserted) in the grooves 60Ba1 and 60Ba2 of the second insulating member 60B, the locking member 70B is placed (inserted) in the grooves 60Bb1 and 60Bb2 of the second insulating member 60B, and the locking member 70C is placed (inserted) in the grooves 60Bc1 and 60Bc2 of the second insulating member 60B.

The tip 20aa of the convex portion 20a of the shielding member 20 has a groove (see fig. 12B) corresponding to the shape and position of the locking member 70, and the groove stably holds the locking member 70 in a clamped manner.

The three locking members 70A, 70B, 70C are the same shape. When the shape of the locking member 70A is described with reference to the drawings, the locking member 70A includes: a support portion 70Aa placed in and supported by a groove formed in the second insulating member 60B; and a protruding portion 70Ab extending downward from the support portion, the tip 70Aba of which approaches or contacts the uppermost fusible conductor chip 50f. In the locking members 70, all the locking members 70 have the same shape, and may have locking members of different shapes.

The heating elements 80A, 80B are mounted on the locking members 70A, 70B, 70C. When the electric current is applied to the heating elements 80A and 80B, the heating elements 80A and 80B generate heat, transfer heat to the locking member 70, and the locking member 70 is heated to soften at a temperature equal to or higher than the softening temperature. The softening temperature refers to a temperature or a temperature range at which a solid phase and a liquid phase exist in a mixed state or coexist. When the locking member 70 becomes a temperature equal to or higher than the softening temperature, it becomes soft to such an extent that it is deformed by an external force.

The softened locking member 70 is easily physically cut by the convex portion 20a of the shielding member 20 pressed by the pressing force of the pressing unit 30. When the locking member 70 is cut, the convex portion 20a of the shielding member 20 is inserted into the gaps 65 and 64 downward in the Z direction.

When the convex portion 20a is inserted into the gaps 65 and 64 downward in the Z direction, the convex portion 20a advances to the lowermost position while cutting the fusible conductor piece. Thus, the convex portion 20a shields the fusible conductor pieces 50a to 50f from the first terminal 91 side and the second terminal 92 side at the fuse portion 53. Thus, the arc discharge generated when the fusible conductor chips 50a to 50f are cut off can be quickly and reliably extinguished.

The heat generated by the heat generating bodies 80A, 80B heats the fusible conductor piece 50f via the locking member 70, and further heats other fusible conductor pieces, so that the fusible conductor pieces 50A to 50f are easily physically cut off. Further, the fusible conductor piece 50f can be thermally fused according to the magnitude of heat generation by the heat generating bodies 80A, 80B. In this case, the convex portion 20a is pushed to the lowermost position as it is.

In the locking member 70, the protruding portion 70Ab contacts the fusible conductor piece 50f. Therefore, when an overcurrent exceeding a rated current flows through the fusible conductor piece, the locking member 70 contacting the fusible conductor piece 50f transfers heat and increases in temperature, and is softened at a temperature equal to or higher than the softening temperature.

When a large overcurrent flows and the fusible conductor piece 50f instantaneously fuses, the generated arc discharge also flows through the locking member 70, and the locking member 70 softens at a temperature equal to or higher than the softening temperature.

In this case, the fusible conductor piece is thermally fused by an overcurrent exceeding a rated current, and the convex portion 20a is inserted into the gaps 65 and 64 while being inserted downward in the Z direction. At this time, the convex portion 20a shields the fusible conductor pieces 50a to 50f from the first terminal 91 side and the second terminal 92 side at the fused portion thereof. Thus, the arc discharge generated when the fusible conductor chips 50a to 50f are cut off can be quickly and reliably extinguished.

Even when the fusible conductor piece has not been thermally fused, the convex portion 20a is pushed to the lowermost position while cutting the fusible conductor piece when the convex portion 20a is inserted into the gaps 65 and 64 in the Z-direction downward. Thus, the convex portion 20a shields the fusible conductor pieces 50a to 50f from the first terminal 91 side and the second terminal 92 side at the fused portion thereof. Thus, the arc discharge generated when the fusible conductor chips 50a to 50f are cut off can be quickly and reliably extinguished.

Fig. 7 shows a protection device having a locking member 71 as a modification of the locking member 70. Fig. 7 also shows an enlarged view of the vicinity of the locking member 71.

The locking member 71 is constituted as follows: only the support portion 71Aa placed and supported in the groove formed in the second insulating member 60B is provided, and no protruding portion for contacting the fusible conductor chip 50f is provided.

Since the locking member 71 does not have a portion that contacts the fusible conductor piece 50f, it is softened only by the heat generating element 80 without being softened even if an overcurrent exceeding a rated current flows through the fusible conductor piece. However, when arc discharge occurs due to a high voltage, the arc discharge reaches the locking member 71, the locking member 71 is fused, and the fusible conductor pieces 50a to 50f are shielded by the convex portions 20a on the first terminal 91 side and the second terminal 92 side at the fused portions.

The locking members 70 and 71 may be made of the same material as the fusible conductor sheet, but in order to be softened rapidly by energization of the heating element 80, a laminate including a low-melting-point metal layer and a high-melting-point metal layer is preferable. For example, a laminate formed by plating the periphery of an alloy containing Sn as a main component having a melting point of 217 ℃ with Ag having a melting point of 962 ℃ can be used.

(heating element)

The heating element 80 is placed in contact with the upper surface of the locking member 70. When a current is applied to the heating element 80, heat is generated, and the locking member 70 is heated by the heat, so that it is softened and melted.

By melting the locking member 70, the shielding member 20 to which the pressing force is applied downward in the Z direction by the pressing unit 30 is inserted into the gap of the fuse element laminate 40, and the fusible conductor sheet 50 is cut, so that the fuse element laminate 40 is shielded on the first terminal 91 side and the second terminal 92 side.

The protection device 100 includes two heating elements 80 (80A, 80B), but is not limited to two.

Fig. 8A to 8F show schematic diagrams of the heat generator 80. Fig. 8A is a plan view of the front surface (surface on the pressing unit 30 side) of the heating element 80. Fig. 8B is a top view of an insulating substrate. Fig. 8C to 8E are perspective plan views showing three layers on the front side of an insulating substrate stacked in order and the lower layer is also visible. Fig. 8C is a plan view of a state in which a resistive layer is laminated on an insulating substrate. Fig. 8D is a plan view of the insulating layer further stacked on fig. 8C. Fig. 8E is a plan view of the electrode layer further laminated on fig. 8D. Fig. 8F is a plan view of the back surface (surface on the fuse element stack 40 side) of the heat generating element 80.

The heating elements 80A and 80B each have: two resistor layers 80-1 (80-1 a, 80-1 b) arranged in parallel and separated from each other on the front surface 80-3A (surface on the pressing unit 30 side) of the insulating substrate 80-3; an insulating layer 80-4 covering the resistive layer 80-1; a heating element electrode 80-5a and a heating element electrode 80-5b formed on the insulating substrate 80-3 and electrically connected to both ends of the resistive layer 80-1 a; the heating element electrode 80-5c and the heating element electrode 80-5d are electrically connected with both ends of the resistance layer 80-1 b; and electrode layers 80-2 (80-2 a, 80-2B) formed on the rear surface 80-3B (surface on the fuse element laminate 40 side) of the insulating substrate 80-3. The resistive layers each include two heating elements 80A and 80B, and this is not necessarily required to include two resistive layers in consideration of a fault protection design that can be mounted so as to be rotated 180 degrees.

The resistive layer 80-1 is made of a material having conductivity that generates heat when energized, such as nichrome, W, mo, ru, or the like, or a material containing the same. The resistive layer 80-1 is formed by: these alloys, compositions, and powders of the compounds are mixed with a resin binder, etc., to prepare a paste, and the paste is patterned on the insulating substrate 80-3 by using a screen printing technique, and fired. The insulating substrate 80-3 is, for example, an insulating substrate such as alumina, glass ceramic, mullite, or zirconia. The insulating layer 80-4 is provided to protect the resistive layer 80-1. As a material of the insulating layer 80-4, for example, an insulating material such as ceramic or glass can be used. The insulating layer 80-4 can be formed by a method of applying a paste of an insulating material and firing the paste.

The front heating element electrodes 80-5a to 80-5d and the rear electrode layers 80-2a to 80-2B of the heating elements 80A and 80B are electrically insulated by an insulating substrate 80-3.

The heating elements 80A and 80B are not limited to those shown in fig. 8A to 8F, and known heating elements may be used.

When the external circuit serving as the current path of the protection device 100 is abnormal and the current path needs to be disconnected, the heating elements 80A and 80B generate heat by being energized by a current control device provided in the external circuit.

(Power supply member)

Fig. 9A and 9B are perspective views of a protection device for explaining a method of pulling out a power feeding member for feeding power to the heating elements 80A, 80B. Fig. 9A shows a case where heating elements 80A and 80B are connected in series. Fig. 9B shows a case where heating elements 80A and 80B are connected in parallel. In this reference example, at least a part of the power feeding member is constituted by an electric wire (wiring member). However, the present invention is not limited thereto, and at least a part of the power feeding member may be formed of a plate-like member, a rod-like member, or the like having conductivity, although not particularly shown.

In FIG. 9A, a power feeding member 90A is connected to a heating element electrode 80-5c of a heating element 80A (see FIG. 8E), a power feeding member 90B is connected to a heating element electrode 80-5a of a heating element 80B (see FIG. 8E), and a power feeding member 90A is connected to a heating element electrode 80-5d of a heating element 80A (see FIG. 8E) and a heating element electrode 80-5B of a heating element 80B (see FIG. 8E). The electrode layer 80-2 of the heating element 80A is connected to the electrode layer 80-2 of the heating element 80B via the locking member 70 (70A, 70B, 70C). In this configuration, the heat generating elements 80A and 80B are heated by supplying power in the path of "the heat generating element electrodes 80-5c of the power supplying members 90A to 80A to the resistance layers 80-1a of the heat generating elements 80A to 80-5d of the heat generating elements 80A to 90B of the power supplying members 90A to 80B to 80-1B of the heat generating elements 80B to 80-5a of the heat generating elements 80B". By this heat generation, the locking members 70 (70A, 70B, 70C) melt, and the shielding member 20 is inserted into the gaps 64, 65 of the fuse element laminate 40. By inserting the shielding member 20 into the gaps 64 and 65 of the fuse element laminate 40, the power feeding member 90A is cut off, and the power supply to the heating elements 80A and 80B is cut off, so that the heat generation by the heating elements 80A and 80B is stopped.

In FIG. 9B, a power feeding member 90c is connected to the heating element electrodes 80-5c of the heating element 80A, and a power feeding member 90e is connected to the heating element electrodes 80-5d of the heating element 80A. The power feeding member 90d is connected to the heating element electrode 80-5a of the heating element 80B, and the power feeding member 90f is connected to the heating element electrode 80-5B (see fig. 8E). In this configuration, a first path from "power feeding member 90c to heat-generating element electrode 80-5c of heat-generating element 80A to resistance layer 80-1a of heat-generating element 80A to heat-generating element electrode 80-5d of heat-generating element 80A to power feeding member 90e" is juxtaposed with a second path from "power feeding member 90d to heat-generating element electrode 80-5a of heat-generating element 80B to resistance layer 80-1B of heat-generating element 80B to heat-generating element electrode 80-5B of heat-generating element 80B to power feeding member 90 f". The power is supplied to the first and second paths, and the heating elements 80A and 80B generate heat. By this heat generation, the locking members 70 (70A, 70B, 70C) melt, and the shielding member 20 is inserted into the gaps 64, 65 of the fuse element laminate 40. In this configuration, the shielding member 20 is inserted into the gaps 64 and 65 of the fuse element laminate 40, so that the power supply to the heating elements 80A and 80B is not interrupted, and the heat generation by the heating elements 80A and 80B continues. By properly stopping the energization of the current control device by other system control (timer or the like), the heat generation of the heating elements 80A, 80B of the protection device 100 after the disconnection can be stopped.

(first terminal, second terminal)

One end portion of the first terminal 91 is connected to the first end portion 51 of the fusible conductor pieces 50a to 50f, and the other end portion is exposed to the outside of the insulating case 10. One end of the second terminal 92 is connected to the second end 52 of the fusible conductor pieces 50a to 50f, and the other end is exposed to the outside of the insulating case 10.

The first terminal 91 and the second terminal 92 may have substantially the same shape or may have different shapes. The thicknesses of the first terminal 91 and the second terminal 92 are not particularly limited, and may be, for example, in a range of 0.3mm to 1.0 mm. The thickness of the first terminal 91 may be the same as or different from the thickness of the second terminal 92.

The first terminal 91 includes an external terminal hole 91a. The second terminal 92 is provided with an external terminal hole 92a. One of the external terminal hole 91a and the external terminal hole 92a is used for connection to the power supply side, and the other is used for connection to the load side. Alternatively, the external terminal hole 91a and the external terminal hole 92a may be used for a current-carrying path connected to the inside of the load. The external terminal hole 91a and the external terminal hole 92a may be through holes having a substantially circular shape in a plan view.

As the first terminal 91 and the second terminal 92, for example, terminals made of copper, brass, nickel, or the like can be used. As the material of the first terminal 91 and the second terminal 92, brass is preferably used from the viewpoint of reinforcing rigidity, and copper is preferably used from the viewpoint of reducing electric resistance. The first terminal 91 and the second terminal 92 may be made of the same material or may be made of different materials.

(method for manufacturing protective device)

The protection device 100 of the present reference example can be manufactured as follows.

First, the fuse element laminate 40 and the first terminal 91 and the second terminal 92 positioned with the jig are prepared. Then, the first ends 51 of the fusible conductor pieces 50a to 50f of the fuse element laminate 40 are connected to the first terminals 91 by soldering.

Further, the second end portion 52 is connected to the second terminal 92 by soldering. As a solder material for soldering, a known material can be used, and from the viewpoint of resistivity and melting point, and coping with environmental lead-free, a material containing Sn as a main component is preferably used. The connection between the first end 51 of the fusible conductor pieces 50a to 50f and the first terminal 91 and the connection between the second end 52 of the fusible conductor pieces 50a to 50f and the second terminal 92 are not limited to soldering, and a known bonding method such as bonding by fusion bonding may be used.

Next, the locking members 70A, 70B, 70C are prepared. The locking members 70A, 70B, 70C are disposed in the grooves 60Ba1 and 60Ba2, the grooves 60Bb1 and 60Bb2, and the grooves 60Bc1 and 60Bc2, respectively, of the second insulating member 60B shown in fig. 3. In addition, a jig having the same shape as the second insulating member 60B may be used.

Next, the heating elements 80A and 80B and the solder paste shown in fig. 8A and 8B are prepared. Then, after a proper amount of solder paste is applied to the connection portions of the locking members 70A, 70B, 70C and the heating elements 80A, 80B, the heating elements 80A, 80B are arranged at the predetermined positions of the second insulating member 60B as shown in fig. 9A. The back sides of the heating elements 80A, 80B are placed on the locking members 70A, 70B, 70C. The locking members 70A, 70B, 70C are soldered to the heating elements 80A, 80B by heating in an oven, reflow oven, or the like.

Next, the power feeding members 90A, 90b, 90A are prepared. The power feeding member 90A is disposed on the power feeding member mounting surface 12, and the power feeding member 90A is connected to the heating element electrodes 80 to 5c of the heating element 80A by soldering. The power feeding member 90B is disposed on the power feeding member mounting surface 12, and the power feeding member 90B is connected to the heating element electrode 80-5a of the heating element 80B by soldering. Further, the power feeding member 90A is connected to the heat generating body electrode 80-5d of the heat generating body 80A and the heat generating body electrode 80-5B of the heat generating body 80B by soldering. The power feeding members 90A, 90B, 90A and the heating elements 80A, 80B may be connected by welding, and a known welding method may be used.

Next, the second holding member 10Bb, the shielding member 20, and the pressing unit 30 are prepared. Then, the pressing unit 30 is disposed in the recess 20ba of the shielding member 20 and is accommodated in the second holding member 10Bb.

Next, while the engaging members 70A, 70B, 70C are fitted into the grooves provided in the tip 20aa of the shielding member 20 and the pressing means 30 is compressed, four protrusions (not shown) formed in the corresponding portions of the second holding member 10Bb are engaged with the respective two recesses 17 formed in the first end portion 10Baa and the second end portion 10Bab of the first holding member 10Ba, respectively, to form the holding member 10B.

Next, the cover 10A is prepared. Then, the holding member 10B is inserted into the accommodation portion 22 of the cover 10A. Next, the adhesive is injected into the terminal adhesive injection port 16 of the holding member 10B, and the gap between the terminal mounting surface 111 and the first terminal 91 and the second terminal 92 is filled. The adhesive is injected into the inclined surface 21 of the elliptical side surface of the cover 10A, which is the case adhesive injection port, to adhere the cover 10A to the holding member 10B. As the adhesive, for example, an adhesive including a thermosetting resin can be used. Thus, the insulating case 10 sealed in the cover 10A is formed.

Through the above steps, the protection device 100 of the present reference example is obtained.

In the protection device 100 of the present reference example, when an overcurrent exceeding a rated current flows through the fuse element 50 (the plurality of fusible conductor pieces 50a to 50 f), the fuse element 50 is thermally blown to break the current path. In addition to the above, the electric current may be supplied to the heating element 80, the locking member 70 that suppresses the movement of the shielding member 20 may be melted, the shielding member 20 may be moved by the pressing unit 30, and the fuse element 50 may be physically cut off to disconnect the current path.

In the protection device 100 of the present reference example, since the movement of the shielding member 20 to which the pressing force is applied by the pressing means 30 is suppressed by the locking means 70, the fuse element 50 (the plurality of fusible conductor pieces 50a to 50 f) is not subjected to the cutting pressing force by the pressing means 30 and the shielding member 20 except when the current path is opened. Accordingly, the time degradation of the fuse element 50 is suppressed, and disconnection caused by the state where the pressing force is applied when the temperature of the fuse element 50 increases when the current path is not required to be disconnected can be prevented.

In the protection device 100 of the present reference example, the fuse element laminate 40 includes a plurality of fusible conductor pieces 50a to 50f arranged in parallel in the thickness direction, and the fusible conductor pieces 50a to 50f are insulated by being brought into close proximity to or in contact with (in close contact with) the first insulating members 60Aa to 60Af and the second insulating member 60B arranged therebetween. Therefore, the current value flowing through each fusible conductor piece 50a to 50f becomes small, the space surrounding the fusible conductor piece 50a to 50f becomes extremely narrow, and the scale of arc discharge generated by fusing is liable to become small. That is, if the fusing space is narrow, the amount of gas in the space becomes small, and the amount of plasma generated by ionization of the gas in the space, which becomes a path through which current flows during arc discharge, becomes small, so that arc extinction is easy at an early stage of arc discharge. Thus, according to the protection device 100 of the present reference example, the insulating case 10 can be made small in size and light in weight.

In the protection device 100 of the present reference example, if the first insulating member 60Aa is disposed between the fusible conductor piece 50a disposed at the lowermost portion of the fusible conductor pieces 50a to 50f and the first holding member 10Ba of the insulating case 10, and the second insulating member 60B is disposed between the fusible conductor piece 50f disposed at the uppermost portion of the fusible conductor pieces 50a to 50f and the second holding member 10Bb of the insulating case 10, the fusible conductor pieces 50a, 50f do not directly contact the first holding member 10Ba and the second holding member 10 Bb. Therefore, carbide serving as a conductive path is not easily formed on the inner surface of the insulating case 10 by arc discharge, and thus leakage current is not easily generated even if the insulating case 10 is miniaturized.

In the protection device 100 of the present reference example, if the first insulating members 60Aa to 60Af and the second insulating member 60B are separated at positions facing the fused portions 53 of the first end portions 51 and the second end portions 52 of the fusible conductor pieces 50a to 50f, when the fusible conductor pieces 50a to 50f are fused at the fused portions 53, the fusion-scattered substances can be prevented from continuously adhering to the surfaces of the first insulating members 60Aa to 60Af and the second insulating member 60B. Accordingly, the arc discharge generated by the fusing of the fusible conductor pieces 50a to 50f can be extinguished early.

In the protection device 100 of the present reference example, at least one of the first insulating members 60Aa to 60Af, the second insulating member 60B, the shielding member 20, the cover 10A of the insulating case 10, and the holding member 10B is formed of a material having a tracking resistance index CTI of 500V or more. Therefore, carbide serving as a conductive path is not easily formed on the surfaces of these components by arc discharge, and thus leakage current is less likely to occur even if the size of the insulating case 10 is miniaturized.

In the protection device 100 of the present reference example, at least one of the first insulating members 60Aa to 60Af, the second insulating member 60B, the shielding member 20, the cover 10A of the insulating case 10, and the holding member 10B is formed of a polyamide-based resin or a fluorine-based resin. Since polyamide resin or fluorine resin is excellent in insulation and tracking resistance, it is easy to achieve both downsizing and weight saving of the protection device 100.

In the protection device 100 of the present reference example, if each of the fusible conductor sheets 50a to 50f is a laminate including a low melting point metal layer and a high melting point metal layer, the low melting point metal layer contains Sn, and the high melting point metal layer contains Ag or Cu, the high melting point metal is melted by the Sn due to the melting of the low melting point metal layer. Therefore, the fusing temperature of the fusible conductor sheets 50a to 50f becomes low. Further, since Ag and Cu have higher physical strength than Sn, the physical strength of the fusible conductor pieces 50a to 50f formed by laminating a high-melting-point metal layer on a low-melting-point metal layer is higher than that of the simple substance of the low-melting-point metal layer. The resistivity of Ag and Cu is lower than that of Sn, and the resistance of the fusible conductor pieces 50a to 50f formed by laminating a high-melting-point metal layer on a low-melting-point metal layer is lower than that of the simple substance of the low-melting-point metal layer. That is, the fuse element is configured to cope with a larger current.

In the protection device 100 of the present reference example, if each of the fusible conductor pieces 50a to 50f has two or more high-melting-point metal layers and one or more low-melting-point metal layers, and the low-melting-point metal layers are arranged in a laminate between the high-melting-point metal layers, the high-melting-point metal layers are arranged on the outer side, and therefore the strength of the fusible conductor pieces 50a to 50f increases. Particularly, when the first end 51 and the first terminal 91 of the fusible conductor pieces 50a to 50f and the second end 52 and the second terminal 92 are connected by soldering, deformation of the fusible conductor pieces 50a to 50f due to heating at the time of soldering is less likely to occur.

In the protection device 100 of the present reference example, when each of the fusible conductor pieces 50a to 50f is a single layer including silver or copper, the specific resistance tends to be lower than when the fusible conductor pieces are a laminate of a high-melting-point metal layer and a low-melting-point metal layer. Therefore, even when the fusible conductor pieces 50a to 50f each composed of a single layer containing silver or copper have the same area and have the same resistance as those of the fusible conductor pieces 50a to 50f each composed of a laminate of a high-melting-point metal layer and a low-melting-point metal layer, the thickness can be reduced. If the thickness of the fusible conductor pieces 50a to 50f is small, the amount of the molten scattered matter when the fusible conductor pieces 50a to 50f are fused is also reduced in proportion to the thickness, and the insulation resistance after the fusing is improved.

In the protection device 100 of the present reference example, each of the fusible conductor pieces 50a to 50f has a fuse portion formed in such a manner that: the fuse portion 53 is provided with a through hole 54, and the cross-sectional area of the fuse portion 53 in the current flowing direction is smaller than the cross-sectional areas of the first end portion 51 and the second end portion 52 in the current flowing direction. Therefore, the fused portion is stable when the rated current is passed through the current path. In the protection device 100 of the present reference example, the through hole 54 is provided in the fuse portion 53, but the method of reducing the cross-sectional area of the fuse portion 53 is not particularly limited. For example, the cross-sectional area of the fuse portion 53 may be reduced by cutting both end portions of the fuse portion 53 into a concave shape and locally thinning the thickness.

(modification)

Fig. 10A and 10B are schematic diagrams of a modification of the first reference example. Fig. 10A is a perspective view of a holding member 10BB as a modification of the holding member 10B. Fig. 10B is a perspective view of a configuration in which the first insulating member 61A and the second insulating member 61B, which are modifications of the first insulating member 60A and the second insulating member 60B, have openings through which the convex portions 20A of the shielding member 20 can move (pass). Fig. 11A shows a perspective view of the second insulating member, and fig. 11B shows a perspective view of the first insulating member. Since the six first insulating members have the same shape, the first insulating members shown in fig. 11B represent their common configuration.

The fuse element laminate in this modification is identical to the configuration shown in fig. 4A to 4C except for the first insulating member. Therefore, in the following description, members common to those shown in fig. 4A to 4C are denoted by the same reference numerals.

Each of the first insulating members 61Aa to 61Af shown in fig. 10B to 11B has a first opening 64A, and the second insulating member 61B has a second opening 65A. The lengths of the first opening 64A and the second opening 65A in the Y direction are longer than the lengths of the fusible conductor pieces 50a to 50f and the convex portion 20a of the shielding member 20 in the Y direction. Thus, after the fusible conductor pieces 50a to 50f are disconnected, the convex portion 20a is inserted into the first opening 64A and the second opening 65A, and the fused portions of the fusible conductor pieces 50a to 50f are securely shielded.

Each of the first insulating members 61Aa to 61Af and the second insulating member 61B has, on both end sides in the Y direction: the vent hole 67A is used to efficiently release the pressure rise caused by the arc discharge generated at the time of opening the fuse element into the pressing unit accommodating space of the insulating case. In the illustrated example, each of the first insulating members 61Aa to 61Af and the second insulating member 61B has five vent holes 67A on both end sides in the Y direction, that is, on the left and right sides sandwiching the first opening 64A or the second opening 65A, but there is no limitation on the number.

The rising pressure generated by the arc discharge is efficiently released to the space of the insulating housing 10 accommodating the pressing unit 30 through the vent hole 67A via gaps (not shown) provided at four corners between the pressing unit supporting portion 20b and the second holding member 10 BBb. As a result, the shielding operation of the shielding member 20 is smoothly performed, and damage to the first insulating members 61Aa to 61Af and the second insulating member 61B is prevented.

The first opening 64A and the second opening 65A are located opposite to the fuse portion 53 disposed between the first end 51 and the second end 52 of the fusible conductor sheets 50a to 50 f.

The materials of the first insulating members 61Aa to 61Af and the second insulating member 61B are preferably the same as those of the first insulating members 60Aa to 60Af and the second insulating member 60B, and the same kind of materials may be used.

The holding members 10BB (the second holding member 10BBb disposed on the upper side in the Z direction and the first holding member 10BBa disposed on the lower side in the Z direction) shown in fig. 10A and 10B are formed in shapes corresponding to modifications of the first insulating member and the second insulating member.

(protection device (second reference example))

Fig. 12A to 15 are schematic views showing a protection device according to a second reference example. The protection device of the second reference example is mainly different from the protection device of the first reference example in the following points: when an overcurrent exceeding a rated current flows through the fusible conductor piece, only the fusible conductor piece is fused to open the overcurrent opening mechanism of the current path. Specifically, the protection device of the second reference example is mainly different from the protection device of the first reference example in the following points: the heating element and the power supply member are not provided.

In the following drawings, the same or substantially the same constituent members as those of the protection device of the first reference example are given the same reference numerals, and the description thereof is omitted.

Fig. 12A is a view corresponding to fig. 2, and is a perspective view schematically showing a portion removed in such a manner as to protect the interior of the device from view. Fig. 12B is a perspective view of the shielding member. Fig. 13 is a sectional view corresponding to fig. 5 of the protection device of the second reference example. Fig. 14 is a cross-sectional view corresponding to fig. 6, and is a cross-sectional view of the protection device in a state where the fuse element is cut off by the shielding member and lowered to the bottom. Fig. 15 is a perspective view schematically showing a state in which the fuse element laminate, the first terminal, and the second terminal are provided on the first holding member.

The protection device 200 shown in fig. 12A to 15 includes: insulating housing 11, fuse element laminate 140, first insulating member 160A, shielding member 120, pressing unit 30, and locking member 170. In the protection device 200 of the present reference example, the current flowing direction refers to the direction in which electricity flows (X direction) when in use, and the cross-sectional area in the current flowing direction refers to the area of the surface (Y-Z surface) in the direction orthogonal to the current flowing direction.

(insulating housing)

The insulating housing 11 has a substantially elliptical columnar shape (the cross section of the Y-Z plane is elliptical at any position in the X direction). The insulating housing 11 is constituted by a cover 110A and a holding member 110B.

Since the protection device 200 does not include a heating element and a power feeding member, the cover 110A and the holding member 110B do not include a heating element portion and a power feeding member portion, which are different from the cover 10A and the holding member 10B.

The holding member 110B is composed of a first holding member 110Ba disposed on the lower side in the Z direction and a second holding member 110Bb disposed on the upper side in the Z direction.

The outer shape of the cover 110A and the holding member 110B is substantially elliptical cylindrical to realize a small size and withstand an increase in internal pressure due to arc discharge, and the amount of material used is suppressed, but the outer shape is not limited to substantially elliptical cylindrical as long as damage due to arc discharge does not occur in accordance with the rated voltage/rated current/blocking capacitance of the protection device, and any shape such as rectangular parallelepiped may be used.

An internal pressure buffer space 15 (see fig. 14) is formed inside the holding member 110B. The internal pressure buffer space 15 has an effect of suppressing: the internal pressure of the protection device 200 increases rapidly due to gas generated by arc discharge generated when the fuse element stack 140 is blown.

As the material of the cover 110A and the holding member 110B, the same material as the cover 10A and the holding member 10B can be used.

(fuse element laminate)

The fuse element laminate 140 includes: a plurality of fusible conductor pieces 50 arranged in parallel in the thickness direction; and a plurality of first insulating members 160A (160 Aa to 160 Ag) disposed in a state of being close to or in contact with each of the plurality of fusible conductor pieces 50 and being disposed outside the lowermost and uppermost fusible conductor pieces 50 among the plurality of fusible conductor pieces 50, and formed with first openings. The plurality of fusible conductor sheets may be collectively referred to as fuse element 50. The fuse element stack 140 is composed of a fuse element and a first insulating member.

The plurality of fusible conductor sheets 50 have the same configuration as the fusible conductor sheets shown in fig. 4A to 4C, and the description of the above features is omitted. The plurality of first insulating members 160A (160 Aa to 160 Ag) are members having the same structure, and have the same structure as the first insulating member 61A shown in fig. 10B, and the description of the above-described features is omitted.

In the protection device 200 shown in fig. 12A to 15, it is different in the following points: the first insulating member is provided at a portion corresponding to the second insulating member 60B provided in the protection device 100. Even in the protection device 200, an insulating member having a different structure from the first insulating member may be provided instead of the first insulating member disposed at the uppermost portion.

Here, the second insulating member 60B is different from the first insulating member 60A in that the second insulating member 60B has a portion where the heating element 80 is disposed. However, the same configuration as the first insulating member 60A may be substituted, in which case the difference in structure between the second insulating member 60B and the first insulating member 60A disappears, and in this case, the protection device 100 and the fuse element laminate 40 are both composed of the fuse element and the first insulating member.

The fuse element laminate 140 has six fusible conductor pieces 50a, 50b, 50c, 50d, 50e, 50f arranged in parallel in the thickness direction (Z direction). First insulating members 160Ab, 160Ac, 160Ad, 160Ae, 160Af are disposed between the fusible conductor sheets 50a to 50f. The first insulating members 160Ab to 160Af are arranged in a state of approaching or contacting the respective fusible conductor chips 50a to 50f. The state of proximity is preferably a state in which the distance between the first insulating members 160Ab to 160Af and the fusible conductor chips 50a to 50f is 0.5mm or less, more preferably 0.2mm or less.

Further, a first insulating member 160Aa is disposed outside the lowermost fusible conductor piece 50a among the fusible conductor pieces 50a to 50f. Further, a first insulating member 160Ag is disposed outside the uppermost fusible conductor piece 50f among the fusible conductor pieces 50a to 50f. The width (length in the Y direction) of the fusible conductor sheets 50a to 50f is narrower than the width of the first insulating members 160Aa to 160Ag.

The fuse element stack 140 is an example in which a plurality of fusible conductor pieces is six, but the number of fusible conductor pieces is not limited to six and may be a plurality.

In addition, in the fusible conductor pieces 50a to 50f, the fusing part 53 configured to be easily fused is easily cut by the convex part 120a of the shielding member 120.

The thickness of the fusible conductor pieces 50a to 50f is set to be a thickness that can be fused by an overcurrent. The specific thickness depends on the material and number (number of sheets) of the fusible conductor pieces 50a to 50f and the pressing force (stress) of the pressing unit 30, and may be in the range of 0.01mm to 0.1mm based on the case where the fusible conductor pieces 50a to 50f are copper foils, for example.

The fusible conductor pieces 50a to 50f may be in the range of 0.1mm to 1.0mm based on the case where the foil is formed by plating the periphery of an alloy containing Sn as a main component with Ag.

The central portion of each of the first insulating members 160Aa to 160Ag in the X direction has a first opening 64A through which the convex portion 120a of the shielding member 120 can move.

The first insulating members 160Aa to 160Ag have: the vent hole 67A is used to efficiently release the pressure rise caused by the arc discharge generated at the time of opening the fuse element into the pressing unit accommodating space of the insulating case. In the illustrated example, the first insulating members 160Aa to 160Ag have five vent holes 67A on both end sides in the Y direction, that is, on the left and right sides sandwiching the first opening 64A, respectively, but there is no limitation on the number.

The rising pressure generated by the arc discharge is efficiently released to the space of the insulating housing 11 accommodating the pressing unit 30 through the vent hole 67A via gaps (not shown) provided at four corners between the pressing unit supporting portion 120b and the second holding member 110 Bb. As a result, the shielding operation of the shielding member 120 is smoothly performed, and damage to the first insulating members 160Aa to 160Ag is prevented.

The first opening 64A is located at a position facing the fuse portion 53 disposed between the first end 51 and the second end 52 of the fusible conductor sheets 50a to 50 f.

(screening member)

The shielding member 120 has: the convex portion 120a faces the fuse element stack 140 side; and a pressing unit supporting portion 120b having a concave portion 120ba that accommodates and supports the lower portion of the pressing unit 30. The tip of the convex portion 120a has a clip groove 120aA for clipping the locking member 170. In the shielding member 120, three clip grooves 120aA are provided, but there is no limitation on the number.

The shielding member 120 is restrained from moving downward by the locking member 170 in a state where a pressing force of the pressing unit 30 is applied downward. Since the protruding portion 170b of the locking member 170 contacts the fusible conductor piece 50f, when an overcurrent exceeding a rated current flows through the fusible conductor piece, the locking member 170 increases in temperature due to heat transfer, and softens at a temperature equal to or higher than the softening temperature. When a large overcurrent flows and the fusible conductor piece 50f instantaneously fuses, the generated arc discharge also flows through the locking member 170, and the locking member 170 softens at a temperature equal to or higher than the softening temperature. The softened locking member 170 is easily physically cut by the convex portion 120a of the shielding member 120 pressed by the pressing force of the pressing unit 30.

When the locking member 170 is cut, the shielding member 120 moves downward without being restrained from moving downward by the locking member 170, and the fusible conductor pieces 50a to 50f are physically cut.

In the shielding member 120, the tip 120aa of the convex portion 120a is sharp, and is shaped so as to easily cut the fusible conductor pieces 50a to 50 f.

Fig. 14 shows a cross-sectional view of the protective device in a state in which the shielding member 120 moves in the first opening 64A of the fuse element laminate 140, and the fusible conductor pieces 50a, 50b, 50c, 50d, 50e, and 50f are cut by the convex portion 120a, so that the shielding member 120 is lowered to the bottom.

The shielding member 120 moves down and down in the first opening 64A of the fuse element stack 140, and the fusible conductor pieces 50f, 50e, 50d, 50c, 50b, and 50a are cut in order by the convex portion 120a of the shielding member 120. In this way, the cut surfaces are shielded and insulated by the convex portions 120a, and the current-carrying path through each fusible conductor piece is physically and reliably disconnected. Thereby, the arc discharge is rapidly extinguished (extinguished).

In a state where the shielding member 120 moves down to the bottom in the first opening 64A of the fuse element laminate 140, the pressing unit support portion 120b of the shielding member 120 presses the fuse element laminate 140 from the first insulating member 160Ag, and the fusible conductor pieces are in close contact with the first insulating members 160Aa to 160 Ag. Therefore, there is no space between them where arc discharge can continue, and the arc discharge is reliably extinguished.

The thickness (length in the X direction) of the convex portion 120a is smaller than the width of the first opening 64A of the first insulating members 160Aa to 160Ag in the X direction. With this configuration, the convex portion 120a can move downward in the Z direction at the first opening 64A.

For example, in the case where the fusible conductor sheets 50a to 50f are copper foils, the difference between the thickness of the convex portion 120a and the width of the first opening 64A in the X direction may be, for example, 0.05 to 1.0mm, and preferably 0.2 to 0.4mm. If the thickness is 0.05mm or more, even if the ends of the fusible conductor pieces 50a to 50f in the case where the minimum thickness after cutting is 0.01mm enter the gaps between the first insulating members 160Aa to 160Ag and the convex portions 120a, the movement of the convex portions 120a is smooth, and the arc discharge can be extinguished more rapidly and reliably. The reason for this is that: when the difference is 0.05mm or more, the convex portion 120a is less likely to be caught. If the difference is 1.0mm or less, the first opening 64A functions as a guide rail for moving the convex portion 120 a. Therefore, the position of the convex portion 120a that moves when the fusible conductor pieces 50a to 50f are fused is prevented from being shifted, and the arc discharge is extinguished more rapidly and reliably. When the fusible conductor pieces 50a to 50f are foils formed by plating the surroundings of an alloy containing Sn as a main component with Ag, the difference between the thickness of the convex portion 120a and the width of the first opening 64A in the X direction may be, for example, 0.2 to 2.5mm, and preferably 0.22 to 2.2mm.

The width (length in the Y direction) of the convex portion 120a is wider than the width of the fusible conductor pieces 50a to 50f of the fuse element stack 140. With this configuration, the convex portion 120a can cut the fusible conductor pieces 50a to 50 f.

The length L of the convex portion 120a in the Z direction has the following length: when the protruding portion 120a is lowered downward in the Z direction, the tip 120Aa of the protruding portion 120a can reach below the first insulating member 160Aa arranged at the lowermost portion in the Z direction among the first insulating members 160Aa to 160 Ag. When the convex portion 120a is lowered below the first insulating member 160Aa disposed at the lowermost portion, it is inserted into the insertion hole 114 formed in the inner bottom surface of the holding member 110 Ba.

With this configuration, the convex portion 120a can cut the fusible conductor pieces 50a to 50 f.

(pressing unit)

The pressing unit 30 is accommodated in the recess 120ba of the shielding member 120 in a state of pressing the shielding member 120 downward in the Z direction.

The pressing unit 30 may use the same unit as that provided in the protection device 100.

(locking Member)

The same structure (shape, material) as that of the locking member 70 can be used as the structure (shape, material) of the locking member 170. The protection device 200 includes three locking members 170, but is not limited to three.

The locking member 170 is held in a state of being inserted into the clip groove 120aA provided in the tip 120aA of the convex portion 120a of the shielding member 120.

The locking member 170 has a T-shape, and includes: a lateral extension portion (support portion) 170a constituted by a first arm portion 170aa and a second arm portion 170 ab; and a longitudinal extension portion (protruding portion) 170b extending downward from a central portion of the lateral extension portion 170 a.

In the protection device 200, the first arm portion 170aa and the second arm portion 170ab of the lateral extension portion 170a are supported by the shielding member side surface 160AgS with the first opening portion 64A of the first insulating member 160Ag interposed therebetween, and the lower end of the longitudinal extension portion 170b is supported by the shielding member side surface 50fS of the fusible conductor piece 50 f. In the illustrated example, the surface 160AgS of the first insulating member 160Ag on the shielding member side does not have a groove in which the locking member 170 is placed, but may have a groove in which the locking member 170 is placed.

When an overcurrent exceeding a rated current flows through the fusible conductor piece 50f, the locking member 170 contacting the fusible conductor piece 50f is heated by heat transfer and softened at a temperature equal to or higher than the softening temperature, when the longitudinal extension 170b is supported by the shielding member-side surface 50fS of the fusible conductor piece 50 f.

In the protection device 200, both the lateral extending portion 170a and the longitudinal extending portion 170b may be supported. Among them, the longitudinal extension 170b is preferably supported so as to contact the shielding member side surface 50fS of the fusible conductor piece 50f, and is preferably supported so as to soften when an overcurrent exceeding a rated current flows through the fusible conductor piece 50 f. When the vertically extending portion 170b does not contact the shielding member side surface 50fS of the fusible conductor sheet 50f, it is preferable to approach the shielding member side surface 50fS.

The three locking members 170 are all the same shape, and may include locking members of different shapes.

When the locking member 170 is at a temperature equal to or higher than the softening temperature, it becomes soft to such an extent that it is deformed by an external force.

The softened locking member 170 is easily physically cut by the convex portion 120a of the shielding member 120 pressed by the pressing force of the pressing unit 30. When the locking member 170 is cut, the convex portion 120a of the shielding member 120 is inserted into the first opening 64A downward in the Z direction.

When the convex portion 120a is inserted into the first opening 64A downward in the Z direction, the convex portion 120a advances to the lowermost position while cutting the fusible conductor piece. Thus, the convex portion 120a shields the fusible conductor pieces 50a to 50f from the first terminal 91 side and the second terminal 92 side at the fuse portion 53. Thus, the arc discharge generated when the fusible conductor chips 50a to 50f are cut off can be quickly and reliably extinguished.

In the locking member 170, the longitudinally extending portion 170b contacts the fusible conductor chip 50f. Therefore, when an overcurrent exceeding a rated current flows through the fusible conductor piece, the locking member 170 contacting the fusible conductor piece 50f transfers heat and increases in temperature, and is softened at a temperature equal to or higher than the softening temperature.

When a large overcurrent flows and the fusible conductor piece 50f instantaneously fuses, the generated arc discharge also flows through the locking member 170, and the locking member 170 softens at a temperature equal to or higher than the softening temperature.

In this case, the fusible conductor piece is thermally fused by an overcurrent exceeding a rated current, and the convex portion 120a is inserted into the first opening 64A while being inserted downward in the Z direction. At this time, the convex portion 120a shields the fusible conductor pieces 50a to 50f from the first terminal 91 side and the second terminal 92 side at the fused portion thereof. Thus, the arc discharge generated when the fusible conductor chips 50a to 50f are cut off can be quickly and reliably extinguished.

Even when the fusible conductor piece has not been thermally fused, the convex portion 120a is pushed to the lowermost position while cutting the fusible conductor piece when the convex portion 120a is inserted into the first opening 64A in the Z direction downward. Thus, the convex portion 120a shields the fusible conductor pieces 50a to 50f from the first terminal 91 side and the second terminal 92 side at the fused portion thereof. Thus, the arc discharge generated when the fusible conductor chips 50a to 50f are cut off can be quickly and reliably extinguished.

The protection device 200 of the second reference example does not have a heat generating body and a power feeding member, and the same or similar members as those of the protection device 100 of the first reference example are common except for this point, and therefore, the description of the manufacturing method thereof is omitted.

In the protection device 200 of the present reference example, when an overcurrent exceeding a rated current flows through the fuse element 50 (the plurality of fusible conductor pieces 50a to 50 f), the fuse element 50 is thermally blown to break the current path.

In the protection device 200 of the present reference example, since the movement of the shielding member 120 to which the pressing force is applied by the pressing means 30 is suppressed by the locking means 170, the fuse element 50 (the plurality of fusible conductor pieces 50a to 50 f) is not subjected to the cutting pressing force by the pressing means 30 and the shielding member 120 except when the current path is opened. Accordingly, the time degradation of the fuse element 50 is suppressed, and disconnection caused by the state where the pressing force is applied when the temperature of the fuse element 50 increases when the current path is not required to be disconnected can be prevented.

In the protection device 200 of the present reference example, the fuse element laminate 140 includes a plurality of fusible conductor pieces 50a to 50f arranged in parallel in the thickness direction, and each of the fusible conductor pieces 50a to 50f is insulated by being brought into close contact with (in close contact with) the first insulating members 160Ab to 160Af arranged between them and the first insulating members 160Aa to 160Ag arranged outside the fusible conductor pieces 50a, 50 f. Therefore, the current value flowing through each fusible conductor piece 50a to 50f becomes small, the space surrounding the fusible conductor piece 50a to 50f becomes extremely narrow, and the scale of arc discharge generated by fusing is liable to become small. Thus, according to the protection device 200 of the present reference example, the insulating housing 11 can be made small in size and light in weight.

In the protection device 200 of the present reference example, if the first insulating member 160Aa is disposed between the fusible conductor piece 50a disposed at the lowermost portion of the fusible conductor pieces 50a to 50f and the first holding member 110Ba of the insulating case 11, and the first insulating member 160Ag is disposed between the fusible conductor piece 50f disposed at the uppermost portion of the fusible conductor pieces 50a to 50f and the second holding member 110Bb of the insulating case 11, the fusible conductor pieces 50a and 50f do not directly contact the first holding member 110Ba and the second holding member 110 Bb. Therefore, carbide serving as a conductive path is not easily formed on the inner surface of the insulating case 11 by arc discharge, and thus leakage current is not easily generated even if the insulating case 11 is miniaturized.

In the protection device 200 of the present reference example, the first insulating members 160Aa to 160Ag have openings at positions facing the fuse portions 53 of the first end portions 51 and the second end portions 52 of the fusible conductor pieces 50a to 50 f. Accordingly, when the fusible conductor pieces 50a to 50f are fused at the fusing part 53, the fused scattered matter can be prevented from continuously adhering to the surfaces of the first insulating members 160Aa to 160 Ag. Accordingly, the arc discharge generated by the fusing of the fusible conductor pieces 50a to 50f can be extinguished early.

In the protection device 200 of the present reference example, at least one of the first insulating members 160Aa to 160Ag, the shielding member 120, the cover 110A of the insulating case 11, and the holding member 110B is formed of a material having a tracking resistance index CTI of 500V or more. Therefore, carbide serving as a conductive path is not easily formed on the surfaces of these components by arc discharge, and thus leakage current is less likely to occur even if the size of the insulating case 11 is miniaturized.

In the protection device 200 of the present reference example, at least one of the first insulating members 160Aa to 160Ag, the shielding member 120, the cover 110A of the insulating case 11, and the holding member 110B is formed of a polyamide-based resin or a fluorine-based resin. Since polyamide resin or fluorine resin is excellent in insulation and tracking resistance, it is easy to achieve both downsizing and weight saving of the protection device 200.

In the protection device 200 of the present reference example, if each of the fusible conductor sheets 50a to 50f is a laminate including a low melting point metal layer and a high melting point metal layer, the low melting point metal layer contains Sn, and the high melting point metal layer contains Ag or Cu, the high melting point metal is melted by the Sn due to the melting of the low melting point metal layer. Therefore, the fusing temperature of the fusible conductor sheets 50a to 50f becomes low. Further, since Ag and Cu have higher physical strength than Sn, the physical strength of the fusible conductor pieces 50a to 50f formed by laminating a high-melting-point metal layer on a low-melting-point metal layer is higher than that of the simple substance of the low-melting-point metal layer. The resistivity of Ag and Cu is lower than that of Sn, and the resistance of the fusible conductor pieces 50a to 50f formed by laminating a high-melting-point metal layer on a low-melting-point metal layer is lower than that of the simple substance of the low-melting-point metal layer. That is, the fuse element is configured to cope with a larger current.

In the protection device 200 of the present reference example, if each of the fusible conductor pieces 50a to 50f has two or more high-melting-point metal layers and one or more low-melting-point metal layers, and the low-melting-point metal layers are arranged in a laminate between the high-melting-point metal layers, the high-melting-point metal layers are arranged on the outer side, and therefore the strength of the fusible conductor pieces 50a to 50f increases. Particularly, when the first end 51 and the first terminal 91 of the fusible conductor pieces 50a to 50f and the second end 52 and the second terminal 92 are connected by soldering, deformation of the fusible conductor pieces 50a to 50f due to heating at the time of soldering is less likely to occur.

In the protection device 200 of the present reference example, when each of the fusible conductor sheets 50a to 50f is a single layer including silver or copper, the specific resistance tends to be lower than when the fusible conductor sheets are a laminate of a high-melting-point metal layer and a low-melting-point metal layer. Therefore, even when the fusible conductor pieces 50a to 50f each composed of a single layer containing silver or copper have the same area and have the same resistance as those of the fusible conductor pieces 50a to 50f each composed of a laminate of a high-melting-point metal layer and a low-melting-point metal layer, the thickness can be reduced. If the thickness of the fusible conductor pieces 50a to 50f is small, the amount of the molten scattered matter when the fusible conductor pieces 50a to 50f are fused is also reduced in proportion to the thickness, and the insulation resistance after the fusing is improved.

In the protection device 200 of the present reference example, each of the fusible conductor pieces 50a to 50f has a fuse portion formed in such a manner that: the fuse portion 53 is provided with a through hole 54, and the cross-sectional area of the fuse portion 53 in the current flowing direction is smaller than the cross-sectional areas of the first end portion 51 and the second end portion 52 in the current flowing direction. Therefore, the fused portion is stable when the rated current is passed through the current path. In the protection device 200 of the present reference example, the through hole 54 is provided in the fuse portion 53, but the method of reducing the cross-sectional area of the fuse portion 53 is not particularly limited. For example, the cross-sectional area of the fuse portion 53 may be reduced by cutting both end portions of the fuse portion 53 into a concave shape and locally thinning the thickness.

(protection device (embodiment))

A protection device 250 according to an embodiment of the present invention will be described with reference to fig. 16 to 19. The protective device 250 of the embodiment mainly differs from the first and second reference examples described above in each configuration including the arrangement of the locking member 270 and the heating element 80. In the drawings of the present embodiment, the same or substantially the same constituent members as those of the first reference example and the second reference example are denoted by the same reference numerals, the same names, or the like, and the description thereof may be omitted.

Fig. 16 is a cross-sectional view showing the protection device 250 of the present embodiment, and specifically, is a cross-sectional view showing the protection device 250 in the form of a cross section (X-Z cross section) perpendicular to the width direction (Y direction).

The protection device 250 has: an insulating case 260, a fuse element (fusible conductor piece) 50, a first terminal 91, a second terminal 92, an insulating member 60, a shielding member 220, a pressing unit 230, a heating element 80, an engaging member 270, and a power feeding member 90.

(insulating housing)

The insulating housing 260 has: at least two (three in the present embodiment) holding members 260Ba, 260Bb, 260Bc are stacked in the up-down direction (Z direction); and a tubular cover 260A accommodating the holding members 260Ba, 260Bb, 260Bc. The cover 260A is fitted to the outer sides of the plurality of holding members 260Ba, 260Bb, 260Bc.

At least two holding members 260Ba, 260Bb are arranged on both sides of the fuse element 50 in the up-down direction. Specifically, among the three holding members 260Ba, 260Bb, 260Bc, the first holding member 260Ba disposed at the lowermost position is disposed below the fuse element 50. Among the three holding members 260Ba, 260Bb, 260Bc, the second holding member 260Bb is disposed above the fuse element 50. Of the three holding members 260Ba, 260Bb, 260Bc, the third holding member 260Bc is disposed uppermost.

The first holding member 260Ba has an inner bottom surface 13 disposed on the upper surface of the bottom wall thereof and facing upward. That is, the insulating housing 260 has the inner bottom surface 13. The inner bottom surface 13 has a groove 14 extending along an opening or a separate portion of the insulating member 60. The groove 14 extends in the width direction (Y direction), and opens upward.

The second holding member 260Bb has a heat-generating body accommodating recess 261. The heat-generating body accommodating recess 261 is disposed on an inner surface of the side wall of the second holding member 260Bb toward the inner side (center side) in the current-carrying direction (X direction). Specifically, the heat-generating body accommodating recess 261 is located at an upper end portion in the inner surface of the side wall of the second holding member 260 Bb. The heat-generating body accommodation recess 261 is recessed outward in the power feeding direction than a portion of the inner surface of the side wall of the second holding member 260Bb that is adjacent to the lower side of the heat-generating body accommodation recess 261.

The arrangement of the heat-generating element accommodation recess 261 is not limited to the inner surface facing the inner side (center side) in the current flowing direction (X direction), and may be arranged, for example, on the inner surface facing the inner side (center side) in the width direction (Y direction) orthogonal to the current flowing direction (X direction) in the side wall of the second holding member 260 Bb.

The heat-generating body accommodating recess 261 is provided in a pair facing each other in the current-carrying direction on the inner surface of the side wall of the second holding member 260 Bb. That is, the pair of heat-generating body accommodation recesses 261 are arranged at the end portion on the first terminal 91 side (+x side) and the end portion on the second terminal 92 side (-X side) in the current-carrying direction in the inner surface of the side wall of the second holding member 260 Bb.

The heat-generating element accommodation recess 261 is not limited to a pair, and may be disposed on one side.

Fig. 18 is a cross-sectional view schematically showing a part of the protection device 250 of fig. 16, specifically, a cross section perpendicular to the width direction (X-Z cross section). As shown in fig. 18, the second holding member 260Bb (i.e., the insulating housing 260) has a second step 263. The second step 263 is disposed at the lower end of the heat-generating body accommodation recess 261, and faces upward. The second step 263 is provided in each (i.e., in a pair of) the pair of heat-generating body accommodation recesses 261.

In the case where one heat-generating body accommodation recess 261 is provided on one side, the second step 263 is provided in one heat-generating body accommodation recess 261.

As shown in fig. 16, the third holding member 260Bc has a pressing unit accommodating recess 262. The pressing unit accommodating recess 262 is disposed on the lower surface of the top wall of the third holding member 260Bc, and is recessed upward.

Fig. 16 shows a case where the pressing means 230 is a conical spring, and the diameter of the upper side is smaller than the diameter of the lower side, and in a case where the diameter of the upper side of the conical spring is wider than the diameter of the lower side, and in a case where the pressing means is a cylindrical spring, the pressing means accommodating recess 262 may not be provided.

The insulating housing 260 accommodates: fuse element 50, a part of first terminal 91, a part of second terminal 92, insulating member 60, shielding member 220, pressing unit 230, heating element 80, locking member 270, and a part of power feeding member 90.

(fuse element)

The fuse element 50 is provided in plural in an up-down direction (thickness direction). In the present embodiment, four fuse elements 50 are arranged in parallel in the up-down direction. Insulating members 60 are disposed between the vertically adjacent fuse elements 50 and above (outside) the uppermost fuse element 50 (50 f), respectively.

Further, the inner bottom surface 13 of the first holding member 260Ba is arranged in a state of approaching or contacting the lower side (outer side) of the fuse element 50 (50 a) located at the lowermost portion. That is, the inner bottom surface 13 is disposed in a state of approaching or contacting the opposite side (i.e., lower side) of the fuse element 50 from the shielding member 220. More specifically, the inner bottom surface 13 is disposed in a state of being close to or in contact with the outer side of the outermost layer (fuse element 50 a) on the opposite side of the shielding member 220 from the plurality of fuse elements 50.

The fuse element 50 has a plate shape extending in the current-carrying direction. A pair of faces (front and rear faces) of the fuse element 50 face in the up-down direction. The vertical direction is a direction perpendicular to the surface of the fuse element 50, and thus may be in other words, a vertical direction. The plurality of fuse elements 50 are stacked in parallel in the vertical direction.

Fuse element 50 has a first end 51 and a second end 52 opposite each other. That is, in other words, the fuse element 50 has a first end 51 and a second end 52 disposed at both ends in the current-carrying direction.

(first terminal, second terminal)

One end of the first terminal 91 is connected to the first end 51, and the other end is exposed to the outside from the insulating housing 260. Specifically, the other end portion of the first terminal 91 protrudes from the insulating housing 260 toward the first terminal 91 side (+x side) in the current-carrying direction.

One end of the second terminal 92 is connected to the second end 52, and the other end is exposed to the outside from the insulating housing 260. Specifically, the other end portion of the second terminal 92 protrudes from the insulating housing 260 toward the second terminal 92 side (-X side) in the energizing direction.

(insulating Member)

A plurality of insulating members 60 are arranged in the up-down direction. In the present embodiment, four insulating members 60 are arranged in parallel in the up-down direction. Each insulating member 60 is disposed in a state of approaching or contacting each fuse element 50. The insulating member 60 has an opening or a separation portion extending in the width direction (Y direction).

The plurality of insulating members 60 are disposed in contact with or close to between and outside the plurality of fuse elements 50. Specifically, the plurality of insulating members 60 include insulating members 60 disposed outside (on the upper side) of the outermost layer (fuse element 50 f) on the shielding member 220 side (i.e., on the upper side) of the plurality of fuse elements 50.

However, the insulating member 60 positioned at the uppermost portion is not particularly shown, but may be integrally formed with the second holding member 260Bb to constitute a part of the second holding member 260 Bb. In this case, the plurality of insulating members 60 are arranged in contact with or in proximity to between the plurality of fuse elements 50.

The openings or the separated portions of the plurality of insulating members 60 overlap each other as viewed in the vertical direction.

(screening member)

The shielding member 220 is disposed above the fuse element 50. The restriction of the downward movement by the locking member 270 described later is released, and the shielding member 220 can be inserted into the opening or the separation portion of the insulating member 60 by the pressing force (in other words, stress or force) of the pressing unit 230 and move downward so as to cut the fuse element 50.

The up-down direction in which the shielding member 220 is moved is also the direction in which the shielding member 220 is inserted into the opening or the separation portion of the insulating member 60, and thus may be in other words, the insertion direction. That is, the shielding member 220 can move in the insertion direction.

The shielding member 220 has a convex portion 220a and a pressing unit supporting portion 220b.

The convex portion 220a is in the shape of a plate extending in the direction of a plane (Y-Z plane) perpendicular to the current flowing direction (X direction). The upper end of the convex portion 220a is connected to the pressing unit support portion 220b. The pressing unit support portion 220b is substantially plate-shaped and extends in a direction of a plane (X-Y plane) perpendicular to the up-down direction (Z direction).

The convex portion 220a protrudes downward from the pressing unit support portion 220b. Specifically, the convex portion 220a protrudes in the insertion direction toward the opening or the separation portion of the insulating member 60 and the fuse element 50.

The convex portion 220a has a tip 220aa disposed at a lower end of the convex portion 220a and extending in the width direction (Y direction). It should be noted that the tip 220aa may be the blade 220aa. In a cross section perpendicular to the width direction (X-Z cross section), the tip 220aa has a V-shape protruding downward.

The pressing unit supporting portion 220b has a concave portion 220ba and a first step portion 225. That is, the shielding member 220 has a first step 225. The concave portion 220ba is recessed downward from the upper surface of the pressing unit supporting portion 220 b.

As shown in fig. 18, the first step portion 225 protrudes from the outer side surface of the pressing unit supporting portion 220 b. Specifically, in the present embodiment, the first step portion 225 is provided in each (i.e., in a pair of) portions of the outer surface of the pressing unit support portion 220b that face both outer sides in the current flowing direction (X direction).

The first step 225 faces the insertion direction of the shielding member 220, specifically, toward the lower side. In the insertion direction (up-down direction), the first step 225 and the second step 263 face opposite sides to each other. The first step 225 and the second step 263 do not overlap each other as viewed in the insertion direction.

(pressing unit)

As shown in fig. 16, the pressing unit 230 is disposed above the shielding member 220. Specifically, the pressing unit 230 is disposed between the upper surface of the pressing unit support portion 220b and the lower surface of the third holding member 260 Bc. The pressing means 230 is a spring (urging member) such as a compression coil spring which is elastically deformable, and in the present embodiment, has a substantially conical shape with a diameter that expands downward.

The lower portion of the pressing unit 230 is disposed (accommodated) in a recess 220ba provided on the upper surface of the pressing unit support portion 220b. The pressing unit 230 is disposed (accommodated) at an upper portion thereof in a pressing unit accommodating recess 262 provided at a lower surface of the third holding member 260 Bc.

The pressing unit 230 presses the shielding member 220 in the insertion direction (lower) of the shielding member 220. Specifically, the pressing unit 230 is mounted in the protection device 250 in a state of being contracted in the up-down direction and elastically deformed, and presses the pressing unit support portion 220b downward by a pressing force (stress, applied force) based on the restoring deformation force.

(heating element, power supply member)

As shown in fig. 16 and 18, the heat generating element 80 has a plate shape, and a pair of surfaces (front surface and back surface) thereof face the current flowing direction (X direction). The heating element 80 is disposed (accommodated) in the heating element accommodating recess 261. The heating element 80 is provided in each (i.e., in a pair) of the heating element accommodating recessed portions 261. In the present embodiment, the heat generating body 80 heats the locking member 270 to soften it.

In the case where the heat-generating body accommodation recess 261 is arranged on the inner surface of the side wall of the second holding member 260Bb facing the inner side (center side) in the width direction (Y direction) orthogonal to the current-carrying direction (X direction), the heat-generating body 80 is arranged in the direction matching the heat-generating body accommodation recess 261. That is, in this case, the pair of surfaces of the heating element 80 face in the width direction (Y direction).

When one heating element accommodation recess 261 is disposed on one side, one heating element 80 is disposed in heating element accommodation recess 261.

The power supply member 90 supplies current to the heating element 80.

(locking Member)

The locking member 270 of the present embodiment is formed by, for example, plating a quadrangular plate-like solder material with Ag. The locking member 270 is disposed adjacent to the heating element 80. The locking member 270 and the heating element 80 are disposed so as to face each other, and in the present embodiment, the direction in which these members face each other is the current flowing direction (X direction). The pair of surfaces (front surface and rear surface) of the locking member 270 face the energizing direction (X direction). The dimension L2 of the locking member 270 in the insertion direction (Z direction) is larger than the dimension L1 of the locking member 270 in the current-carrying direction (the dimension in the direction from the heating element 80 toward the locking member 270) as viewed in the width direction (Y direction). Although not particularly shown, in the present embodiment, the dimensions of the locking member 270 in the width direction (Y direction) are larger than the dimensions L1 and L2. That is, the locking member 270 has a rectangular plate shape with the width direction as the longitudinal direction.

In the case where the heat-generating body accommodation recess 261 is arranged on the inner surface of the side wall of the second holding member 260Bb facing the inner side (center side) in the width direction (Y direction) orthogonal to the current-carrying direction (X direction), the locking member 270 is arranged in the direction matching the heat-generating body accommodation recess 261. That is, in this case, the pair of surfaces of the locking member 270 face the width direction (Y direction), and the direction in which the locking member 270 faces the heating element 80 is the width direction (Y direction). In this case, the dimension L2 of the locking member 270 in the insertion direction (Z direction) is larger than the dimension L1 of the locking member 270 in the width direction (Y direction) as viewed from the current flowing direction (X direction) (the dimension in the direction from the heating element 80 toward the locking member 270).

The locking members 270 are disposed adjacent to the pair of heating elements 80, and a pair is provided. One of a pair of surfaces (front surface and back surface) of each locking member 270 is disposed close to or in contact with heat generating element 80. The other of the pair of surfaces of the locking member 270 is disposed close to or in contact with the outer surface of the pressing unit support portion 220b of the shielding member 220.

When one heating element accommodation recess 261 is disposed on one side, locking member 270 is disposed adjacent to one heating element 80.

Further, a pair of end surfaces of the locking member 270 facing in the insertion direction (up-down direction) are sandwiched by the first step 225 and the second step 263. That is, the locking member 270 is sandwiched between the pressing unit supporting portion 220b of the shielding member 220 and the second holding member 260Bb of the insulating housing 260 in the insertion direction and supported. In this way, the locking member 270 is clamped and locked between the insulating housing 260 and the shielding member 220 in the insertion direction of the shielding member 220. That is, the locking member 270 is locked between the insulating housing 260 and the shielding member 220, and suppresses movement of the shielding member 220.

Fig. 17 and 19 are cross-sectional views (X-Z cross-sectional views) showing the protection device 250 or a part thereof, and show a state in which the shielding member 220 moves downward in the insertion direction.

When power is supplied from power supply member 90 to heat generator 80, heat generator 80 generates heat. When the heating element 80 generates heat, the locking member 270 is softened by the heat. The locking member 270 is softened, and the shielding member 220 moves while separating the locking member 270 by the pressing force of the pressing unit 230. Specifically, for example, as shown in fig. 19, the softened locking member 270 is separated into the heating element 80 side and the shielding member 220 side. Thereby, the shielding member 220 can move downward.

When the restriction of the downward movement of the shielding member 220 by the locking member 270 is released, the shielding member 220 moves downward by the pressing force of the pressing unit 230. The shielding member 220 moves in the opening or the separation portion of the insulating member 60 to cut the fuse element 50, thereby turning off the energization of the fuse element 50. Further, the shielding member 220 cuts the fuse element 50, and shields each portion of the cut fuse element 50 from each other in the energizing direction of the fuse element 50.

As shown in fig. 17, in the present embodiment, the shielding member 220 moves downward, whereby the tip 220aa of the convex portion 220a is disposed in the groove 14. That is, the tip 220aa of the shielding member 220 in the insertion direction can be inserted into the groove 14. The shielding member 220 is movable in the opening portions or the separated portions of all the insulating members 60, and in the present embodiment, is also movable in the groove 14.

Here, fig. 20 and 21 are cross-sectional views (X-Z cross-sectional views) showing a part of a protection device 250 according to a modification of the present embodiment. In this modification, a pair of locking members 271 made of, for example, a copper plate or the like is used; for example, a fixing member 272 made of solder or the like is disposed between the pair of locking members 271, and fixes the locking members 271 in place of the locking members 270. In this modification, the heating element 80 heats and softens the fixing member 272.

The fixing member 272 softens, and the shielding member 220 moves while separating the fixing member 272 by the pressing force of the pressing unit 230. Specifically, for example, as shown in fig. 21, the softened fixing member 272 is separated into one of the pair of locking members 271 sandwiching the fixing member 272 on the side of the locking member 271 and the other locking member 271. Thereby, the shielding member 220 can move downward.

In the protection device 250 of the present embodiment, when an overcurrent exceeding a rated current flows through the fuse element 50, the fuse element 50 is thermally blown to disconnect a current path. In addition to the above, the current may be supplied to the heat generating element 80 to soften the locking member 270 or the fixing member 272 that suppresses the movement of the shielding member 220, and the pressing force of the pressing unit 230 may move the shielding member 220 to physically cut off the fuse element 50 and break the current path.

In the present embodiment, the fuse element 50 is preferably in close proximity to or in contact with the insulating member 60. Therefore, there is no space between fuse element 50 and insulating member 60 in which arc discharge can continue, and the arc discharge is reliably extinguished. In the present embodiment, the locking members 270 and 271 are not disposed near the fuse element 50, but are provided between the insulating case 260 and the shielding member 220, and are locked to these members to restrict downward movement of the shielding member 220.

Therefore, the locking members 270 and 271 can be disposed away from the fuse element 50, the insulating member 60, and the like, which may increase in temperature when the protection device 250 is energized (in normal use). Therefore, the influence of the function of the locking members 270 and 271 due to the temperature rise of each member can be suppressed.

Further, since the pressing force of the pressing unit 230 is not transmitted to the fuse element 50 and the insulating member 60 via the locking members 270 and 271, the functions of the fuse element 50 and the insulating member 60 can be maintained well for a long period of time.

Further, the tip 220aa of the convex portion 220a of the shielding member 220 can be disposed closer to the fuse element 50 and the insulating member 60. Thus, the outer dimension of the insulating housing 260 in the vertical direction (insertion direction, thickness direction) can be suppressed to be small, and the protection device 250 can be miniaturized.

As described above, according to the present embodiment, the protection device 250 is provided, which is capable of preventing large-scale arc discharge from occurring when the fuse element 50 is blown, reducing the size and weight of the insulating case 260, and having both the overcurrent breaking function against high voltage and large current and the breaking function based on the breaking signal.

In the present embodiment, the locking member 270 or the fixing member 272 is softened by the heat generated by the heat generating body 80, and the shielding member 220 moves downward while separating the locking member 270 or the fixing member 272 by the pressing force of the pressing unit 230. Since the downward movement restriction of the shielding member 220 is stably released, the energization of the fuse element 50 can be more reliably turned off.

In the present embodiment, when the shielding member 220 moves downward, the tip 220aa of the convex portion 220a is inserted into the groove 14 of the inner bottom surface 13 of the insulating housing 260. Thus, the fuse element 50 near or contacting the inner bottom surface 13 can be reliably cut by the shielding member 220.

In the present embodiment, the dimension L2 of the locking member 270 in the insertion direction is larger than the dimension L1 of the locking member 270 in the current-carrying direction (the dimension in the direction from the heating element 80 toward the locking member 270) as viewed in the width direction (Y direction). Alternatively, the dimension L2 of the locking member 270 in the insertion direction is larger than the dimension L1 of the locking member 270 in the width direction (the dimension in the direction from the heating element 80 toward the locking member 270) as viewed in the current flowing direction (X direction).

With the above configuration, the shearing force in the insertion direction of the locking member 270 is increased, and therefore the locking member 270 can be stably held (locked) between the insulating housing 260 and the shielding member 220.

In the present embodiment, the pair of end surfaces of the locking members 270 and 271 facing in the insertion direction are sandwiched between the first step 225 and the second step 263, and the first step 225 and the second step 263 do not overlap with each other when viewed in the insertion direction.

According to the above configuration, when the locking member 270 or the fixing member 272 fixing the locking member 271 is softened and the shielding member 220 moves downward by the pressing force of the pressing unit 230, the first step 225 and the second step 263 holding the locking members 270, 271 are reliably displaced in the insertion direction. Therefore, the first step 225 and the second step 263 can reliably turn off the current of the fuse element 50 without interfering with the downward movement of the shielding member 220.

(modification)

Fig. 22 is a cross-sectional view (X-Z cross-sectional view) showing a part of a protection device 250 according to a modification of the embodiment. In this modification, one or both of the two holding members 260Ba, 260Bb of the insulating housing 260 are integrally formed with the insulating member 60. In the illustrated example, one of the two holding members 260Ba, 260Bb (holding member 260 Bb) is integrally formed with the insulating member 60. Further, the fuse element 50 is provided as a single layer (one).

In the above configuration, the insulating member 60 is integrated with the holding members 260Ba, 260 Bb. Therefore, the number of parts can be reduced, and the manufacturing of the protection device 250 can be facilitated, or the manufacturing cost can be reduced.

(modification)

Fig. 23 is a schematic diagram of a fuse element 550 according to a modification of the embodiment, and is a plan view corresponding to fig. 4A.

In this modification, the fuse element 550 has a first fusible conductor 555 and a second fusible conductor 553 having a lower melting point than the first fusible conductor 555. Further, the first fusible conductor 555 and the second fusible conductor 553 are connected in series in energization. That is, the first fusible conductor 555 and the second fusible conductor 553 are electrically connected in series, and in this modification, are arranged in the current-carrying direction (X direction).

The first fusible conductor 555 and the second fusible conductor 553 may be arranged in the insertion direction (Z direction). Specifically, although not shown, the fuse element 550 may be configured such that the vicinities of the distal ends of the inner sides (center sides) in the current-carrying direction (X-direction) of the two first fusible conductors 555 are overlapped, and the overlapped gaps may be connected by the second fusible conductors 553. That is, the tip ends of the two first fusible conductors 555 and one second fusible conductor 553 located between the tip ends may be arranged so as to overlap each other when viewed in the insertion direction (Z direction), and the first fusible conductor 555 and the second fusible conductor 553 may be electrically (electrically) connected in series.

With this structure, the conduction distance of the second fusible conductor 553 having a higher resistivity than the first fusible conductor 555 can be shortened, and the rise in resistance of the fuse element 550 can be suppressed.

In addition, a second fusible conductor 553 is disposed between the two first fusible conductors 555.

According to the above configuration, the second fusible conductor 553 can be disposed at the central portion of the fuse element 550 in the current-carrying direction, and the fuse element 550 can be blown from the central portion.

In this modification, when a current exceeding a rated current flows through the current path of the fuse element 550, the second fusible conductor 553 blows out earlier than the first fusible conductor 555, and therefore the position of the portion of the fuse element 550 where the current is disconnected is stable. Accordingly, the current flow to fuse element 550 can be interrupted from 1.5 to 2 times the rated current flow to 10 times or more explosive interruption, without damaging insulating member 60 or insulating case 260.

Further, by the heat generation of the heat generating body 80, the shielding member 220 moves, and the second fusible conductor 553 is cut off.

According to the above configuration, the second fusible conductor 553 having a low melting point in the fuse element 550 is cut by the downward movement of the shielding member 220. Even when time is required for blowing the second fusible conductor 553 when an overcurrent flows, the fuse element 550 can be reliably cut by the shielding member 220.

In the case where the fuse element 550 is configured such that the vicinities of the distal ends of the two first fusible conductors 555 are overlapped and connected by the second fusible conductor 553, the first fusible conductor 555 is cut by the shielding member 220 moving downward. In this case, the cross-sectional area of the cut portion of the first fusible conductor 555 is preferably smaller than the cross-sectional area of the portion other than the cut portion of the first fusible conductor 555.

The protection device of the present invention is not limited to the above embodiment.

The present invention may be combined with the respective configurations described in the above embodiments, modifications, reference examples, and the like, and may be added, omitted, substituted, and other modifications without departing from the scope of the present invention. The present invention is not limited to the embodiments and the like described above, but is limited only by the claims.

Industrial applicability

According to the protection device of the present invention, large-scale arc discharge is not easily generated when the fuse element is blown, and the size of the insulating case is reduced. Further, it is possible to provide a protection device having both an overcurrent cutoff function for high voltage and large current and a cutoff function based on a cutoff signal. Therefore, the method has industrial applicability.

Description of the reference numerals

10. 11, 260: an insulating housing; 20. 120, 220: a shielding member; 30. 230: a pressing unit; 50. 550). A fuse element; 51: a first end; 52: a second end; 60. 60A, 60B, 160A: an insulating member; 64. 65: a separation section; 64A, 65A: an opening portion; 70. 70A, 70B, 70C, 71, 170, 270, 271: a locking member; 80: a heating element; 90. 90A, 90b, 90c, 90d, 90e, 90f, 90A: a power supply member; 91: a first terminal; 92: a first terminal; 100. 200, 250: a protection device; 272: a fixing member; 555: a first fusible conductor; 553: a second fusible conductor.

Claims

1. A protection device, having: the fuse element, the insulating housing that holds the fuse element, the first terminal and the second terminal, still have:

an insulating member disposed in a state of approaching or contacting the fuse element, and having an opening or a separation portion formed therein;

a shielding member movable in an insertion direction into the opening or the separation portion of the insulating member so as to intercept the fuse element;

a pressing unit that presses the shielding member in an insertion direction of the shielding member;

a locking member that is locked between the insulating housing and the shielding member, and suppresses movement of the shielding member;

A heating element that heats and softens the locking member or a fixing member that fixes the locking member; and

a power supply member for supplying a current to the heating element,

the fuse element has a first end portion and a second end portion which are opposite to each other, one end portion of the first terminal is connected to the first end portion, the other end portion is exposed to the outside from the insulating case, one end portion of the second terminal is connected to the second end portion, the other end portion is exposed to the outside from the insulating case,

the insulating housing further accommodates the insulating member, the shielding member, the pressing unit, the locking member, the heating element, and a part of the power feeding member.

2. The protection device of claim 1, wherein,

the heat generating body generates heat, and the locking member or the fixing member is softened, so that the shielding member moves while separating the locking member or the fixing member by the pressing force of the pressing unit,

further, the shielding member moves in the opening portion or the separation portion of the insulating member to cut the fuse element, thereby turning off the energization of the fuse element.

3. The protection device of claim 2, wherein,

the shielding member cuts the fuse element, and each portion of the fuse element to be cut shields each other in the energizing direction of the fuse element.

4. The protection device according to any one of claim 1 to 3, wherein,

the pressing unit is a spring.

5. The protection device according to any one of claim 1 to 3, wherein,

at least one of the insulating member, the shielding member, and the insulating case is made of a material having a tracking resistance index CTI of 500V or more.

6. The protection device according to any one of claim 1 to 3, wherein,

at least one of the insulating member, the shielding member, and the insulating case is formed of one resin material selected from the group consisting of polyamide-based resin and fluorine-based resin.

7. The protection device according to any one of claim 1 to 3, wherein,

the fuse element is a laminate including a low-melting-point metal layer containing tin and a high-melting-point metal layer containing silver or copper.

8. The protection device of claim 7, wherein,

The fuse element is a laminate having two or more high-melting-point metal layers and one or more low-melting-point metal layers, and the low-melting-point metal layers are disposed between the high-melting-point metal layers.

9. The protection device according to any one of claim 1 to 3, wherein,

the fuse element is a single layer body containing silver or copper.

10. The protection device according to any one of claim 1 to 3, wherein,

the fuse element has a fusing portion between the first end portion and the second end portion, and a cross-sectional area of the fusing portion in the current flowing direction is smaller than a cross-sectional area of the first end portion and the second end portion in the current flowing direction from the first end portion toward the second end portion.

11. The protection device according to any one of claim 1 to 3, wherein,

the fuse element has a first fusible conductor and a second fusible conductor having a lower melting point than the first fusible conductor,

the first fusible conductor and the second fusible conductor are connected in series in energizing.

12. The protection device of claim 11, wherein,

the second fusible conductor is disposed between two of the first fusible conductors.

13. The protection device of claim 11, wherein,

the shielding member moves by heat generation of the heat generating body, and the second fusible conductor is cut off.

14. The protection device according to any one of claim 1 to 3, wherein,

the insulating housing has an inner bottom surface disposed in a state of approaching or contacting an opposite side of the fuse element from the shielding member,

the inner bottom surface has a groove extending along the opening portion or the separation portion of the insulating member,

the tip of the shielding member in the insertion direction can be inserted into the groove.

15. The protection device according to any one of claim 1 to 3, wherein,

the protection device has:

a plurality of the fuse elements stacked in parallel in a direction perpendicular to a surface of the plate-shaped fuse element; and

a plurality of the insulating members disposed in contact with or in proximity to between the plurality of the fuse elements,

the opening portions or the separation portions of the plurality of insulating members overlap each other as viewed in the vertical direction, and the shielding member is movable in all of the opening portions or the separation portions.

16. The protection device of claim 15, wherein,

The plurality of insulating members include the insulating member disposed outside of the outermost layer of the shielding member side of the plurality of fuse elements,

the insulating housing has an inner bottom surface disposed in a state of being close to or in contact with an outer side of an outermost layer of the plurality of fuse elements on an opposite side from the shielding member,

the shielding member is movable in all of the opening portions or the separation portions and the grooves.

17. The protection device according to any one of claim 1 to 3, wherein,

the protection device has:

a plurality of the insulating members disposed in contact with or close to between and outside the plurality of the fuse elements,

18. The protection device according to any one of claim 1 to 3, wherein,

The insulating housing has at least two holding members arranged on both sides of the plate-shaped fuse element in a direction perpendicular to the surface of the fuse element,

one or both of the two holding members are integrally formed with the insulating member.

19. The protection device according to any one of claim 1 to 3, wherein,

the locking member is clamped between the insulating shell and the shielding member in the inserting direction of the shielding member,

the dimension of the locking member in the insertion direction is larger than the dimension of the locking member in the direction from the heating element toward the locking member, as viewed in a width direction orthogonal to the current-carrying direction of the fuse element and the insertion direction of the shielding member, or as viewed in the current-carrying direction.

20. The protection device according to any one of claim 1 to 3, wherein,

the shielding member has a first step directed in the insertion direction of the shielding member,

the insulating housing has a second step portion facing an opposite side of the first step portion in an insertion direction,

a pair of end surfaces of the locking member facing in the insertion direction are sandwiched by the first step portion and the second step portion,

The first step and the second step do not overlap each other as viewed from the insertion direction.