JP2843823B2 - Fusible circuit breaker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thin and compact fusible circuit breaker, which is used for protection of a low-voltage circuit.

2. Description of the Related Art A fusible circuit breaker for protecting a circuit by interrupting a current by melting a fusible portion when a current flowing in a circuit becomes an overcurrent is well known in high-voltage and low-voltage electric wiring and electric equipment. is there.

These fusible circuit breakers connect claw-shaped or sword-shaped terminals connected to circuit contacts to plate-shaped fusible pieces, except for those composed of only thread-shaped or plate-shaped fusible pieces that are directly connected to circuit contacts. Most of them are provided at both ends.

However, these conventional fusible circuit breakers are inevitably large because they have a configuration in which terminals are further extended at both ends of a fusible piece having a considerable length, and the contacts on the circuit side for connecting the terminals are also screws or screws. Because of the configuration using clips, it occupies a considerable height. Therefore, for example, the contact interval is 10-20 mm
Therefore, it is impossible to install the device in a very narrow space with a height margin of about 3 to 5 mm.

On the other hand, in recent years, as a power source for a camera, a mobile phone, or the like, a battery in which a plurality of batteries are combined in series and housed and sealed in a case made of an insulating material and inserted and used is increasing. Since the package in which the battery is housed in the case is required to be small, there is little room inside. For this reason, a circuit breaker with a synthetic resin with PTC characteristics interposed between thin plate-shaped terminals is used for both battery connection and protection of batteries, circuits, and equipment, and the terminals are spot-welded to battery electrodes. Connected things are offered to the market. Since this circuit breaker is thin, it can be installed in a very narrow space.However, it limits current when the temperature rises and returns when the temperature drops. And sealed batteries are susceptible to deterioration due to thermal effects, and if this accumulates, damage to the case,
It is extremely dangerous because it may cause malfunction and fire.

[Problems to be Solved by the Invention] The present invention does not have a thin and small fusible circuit breaker that can be installed in a very narrow space, and performs a protection switch operation having an automatic return function that is used in some cases. It is intended to solve the above-mentioned problem that circuit breakers are dangerous.
It is an object of the present invention to provide a fusible circuit breaker that is thin and small and cuts off due to an overcurrent, cuts off the current, maintains a required shape, and is easy to handle.

[Means for Solving the Problems] Means taken by the present invention to solve the problems are as follows.

That is, a cantilevered heat-generating portion is integrally formed along a side edge of a plurality of terminal portions made of a springy metal thin plate into a slender plate shape, and a free end of the heat-generating portion is formed of a low melting point alloy. A fusible shut-off piece having a structure in which a locking hole is provided near the heat-generating portion of the terminal portion, and a main body and a lid made of an insulating material, one of which is provided with a mounting projection and the other is mounted on the other. This was combined with a protective case having a hole. And the mounting projections penetrate the locking hole and the mounting hole to separate the terminal portions from each other and sandwich a part of them to connect the main body and the lid,
The heat generating portion is housed inside the protective case, and a part of the terminal portion protrudes outside the protective case.

[Operation] The portion of the terminal protruding from the protective case is fixed to the circuit contacts and electrically connected. The amount of heat generated is determined by the volume of the heat generating portion, and the melting point is determined by the composition of the joint. Therefore, the current interruption timing when an overcurrent flows is arbitrarily determined. Then, when the joint is melted, the heat generating parts are separated from each other by their own spring force, restored to a linear state, and cut off the current.

The terminal portion is fixed to the protective case by the mounting projection and does not move, and at the same time, the heat generating portion is housed in the protective case, so there is no fear of damage or dirt adhering.

Embodiment 1 A first embodiment of the present invention will be described with reference to FIGS.

The fusible blocking piece 1 of this embodiment is made of a conductive and highly springable metal such as phosphor bronze or nickel silver, and the two terminal portions 2 and 5 formed in a flat rectangular thin plate are close to each other. The heat-generating portions 3 and 6 in the form of elongated plates are formed in a single plane along the opposing side edges and rise up at a right angle, and are locked at a position near the side edges. Holes 4, 7
Are formed, and the free ends of the heat generating portions 3 and 6 are joined by a joining portion 8 made of a low melting point alloy such as solder.

Further, the protective case 11 of this embodiment is made of an insulating material in which glass fiber for reinforcement is mixed as desired with a heat-resistant synthetic resin such as polycarbonate, for example, and a flat substantially square flat body 12 and a flat lid body 20 are formed. The main body 12 has a bottom wall 13, four side walls 14, and two pedestals 15, 15 sandwiching a central recess 18, and a cylindrical mounting projection 16 at the center of the upper surface of the pedestals 15, 15. 16 are protruding each,
Outer side walls 14 of the pedestals 15, 15 are cut out to form window holes 17, 17, and a cutout step 19 is provided in a portion of the side wall 14 facing the pedestals 15, 15. Lid body 20 is mounting projection 1
It has two mounting holes 21, 21 penetrating through 6, 16, and protruding edges 22, 22 fitted into the window holes 17, 17.

Then, the heat generating portions 3 and 6 joined by the joining portion 8 of the fusible blocking piece 1 are loosely inserted into the recesses 18 and the terminal portions 2 and 5 are inserted.
Are placed on the pedestals 15 with the locking holes 4 and 7 fitted in the mounting projections 16 and partly projecting outward from the window holes 17 and 17, and the lid 20 is further placed on the bases 15 and 15. Are fitted in the mounting holes 21, 21 in the mounting projections 16, 16, and the projections 22, 22 are fitted in the window holes 17, 17, and are superimposed on the notch step portion 19.
The portions of the terminal portions 2 and 5 close to the heat generating portions 3 and 6 are sandwiched by the caulking portions 23 and 23 formed by heating and softening the ends of the mounting projections 16 and 16 protruding from the portions 21 and 21 to form a connection with the main body 12. The lid body 20 is connected.

The mounting projections 16 and 16 have the locking holes 4 and 7 and the mounting holes 21 and 21 fitted with almost no gap and separate the terminal portions 2 and 5 from each other. Therefore, the heat generating portions 3 and 6 are respectively bent. Have been. Further, the terminal portions 2 and 5 are sandwiched between the pedestals 15 and 15 and the lid body 20, and are fixed to the protective case 11 without moving together with the fact that the mounting projections 16 and 16 penetrate. The heat generating units 3 and 6 are housed in a sealed protective case 11.

The heat generation amount of the heat generating portions 2 and 5 is determined by the cross-sectional area and the length, that is, the volume, and the melting point of the bonding portion 8 is determined by the composition of the low melting point alloy. Therefore, by appropriately selecting these, the joint 8 when an overcurrent flows is formed.
Since the melting time is adjusted, an arbitrary delay characteristic can be given. Further, when the joining portion 8 is melted, the heat generating portions 2 and 5 are separated from each other by their own spring force and restored to a linear state, thereby reliably interrupting the current. An arbitrary delay characteristic can also be provided by changing the degree of curvature of the heat generating portions 3 and 6 by changing the interval between the terminal portions 2 and 5 and adjusting the spring force.

FIG. 5 shows an example of use of the fusible circuit breaker of the first embodiment, in which two batteries 32, 34 housed in a case 31 made of synthetic resin.
The terminal portions 2 and 5 are fixed to the anode 33 and the cathode 35 by spot welding and sealed with a cover 36 made of synthetic resin. This fusible circuit breaker is about 20mm in length, about 10mm in width, and about 2m in height
m and can be installed in a narrow space 37.

FIG. 6 shows a production example of the fusible blocking piece 1 in the first embodiment, in which cuts 9a and 10a are provided along opposing side edges of two thin plates 9 and 10 of the material (A). Next, by bending the outer sides of the cutouts 9a and 10a at right angles along the cuts 9a and 10a, the terminal portions 2 and 5 and the cantilevered heat generating portions 3 and 6 are formed integrally therewith (B). The free ends of 3 and 6 are joined by the joint 8 (C).

The fusible shut-off piece 1 manufactured in this manner is in a state where the terminal portions 2 and 5 are almost in contact with each other by the spring force of the heat generating portions 3 and 6. Let me do.

Embodiment 2 A second embodiment of the present invention will be described with reference to FIG. 7 to FIG.

The protective case 31 of this embodiment includes a flat main body 32 and a flat lid 35 having a substantially flat surface and made of the same insulating material as in the first embodiment, and the main body 32 is formed at the center of the upper surface. A recess 33 and two mounting holes 34 formed on both sides thereof,
34. The lid 35 has a top wall 36, four circumferential side walls 37, and two cylindrical mounting projections 38, 38 protruding from the lower surface of the top wall 36.
Notch-shaped window holes 39, 39 are provided in portions opposing the side wall 37 with the mounting protrusions 38, 38 therebetween.

Further, in this embodiment, the same soluble blocking piece 1 as the first embodiment is used.
The heat generating portions 3 and 6 joined by the joining portion 8 are positioned on the depression 33, and the terminal portions 2 and 5 are formed on the upper surface of the main body 32 with a part thereof protruding outward. In a state where the lid 35 is overlapped and the mounting projections 38, 38 pass through the locking holes 4, 7, and the mounting holes 34, 34 from above and the window holes 39, 39 are fitted in the terminal portions 2, 5, respectively. The mounting protrusion protrudes from the mounting holes 34, 34, with the side wall 37 placed on the upper surface peripheral portion of the main body 32 and stacked.
The main body 32 and the lid 35 are connected to each other with the terminal portions 2 and 5 sandwiched by caulking portions 40 and 40 formed at the ends of 38 and 38.

Also in this embodiment, the mounting projections 38, 38
The mounting portions 34 and 34 are fitted with almost no gap, and the terminal portions 2 and 5 are separated from each other. Therefore, the heat generating portions 3 and 6 are curved respectively. Further, the terminal portions 2 and 5 are fitted into the window holes 39 and 39, and are fixed to the protective case 31 without moving in combination with the through-holes of the mounting protrusions 38 and 38. Are housed in a sealed protective case 31.

Embodiment 3 A third embodiment of the present invention will be described with reference to FIG. 10 to FIG.

In the fusible blocking piece 41 of this embodiment, the same two terminal portions 42 and 45 as those of the first embodiment are arranged close to each other and vertically parallel to each other, and an elongated plate along their corresponding side edges. The heat-generating portions 43 and 46 are formed in a cantilever manner, and locking holes 44 and 47 are formed near the side edges thereof.
The free ends of 46 are joined by a joining portion 48 similar to that of the first embodiment.

Further, the protective case 51 of this embodiment comprises a flat main body 52 having a substantially square plane and made of the same insulating material as that of the first embodiment, and a flat lid body 60. Side wall 54, a recess 58 formed on one side of the inside thereof, and a pedestal 55 formed on the other side, and a step having a large diameter at the base end and a small diameter at the tip end at the center of the upper surface of the pedestal 55. A cylindrical mounting projection 56 is provided so as to protrude, and a side wall 54 on the outer side of the pedestal 55 is cut out to form a window hole 57. Further, the side wall 54 has a cutout step 59 over the entire circumference. Is provided. Lid body 60
Has a mounting hole 61 penetrating through the mounting projection 56.

The heat generating portions 43 and 46 joined by the joining portion 48 of the fusible blocking piece 41 are located above the recess 58, and the lower terminal portion
45 fits the locking hole 47 into the large-diameter portion of the mounting projection 56 and overlaps with the pedestal 55, and the upper terminal portion 42 fits the locking hole 47 into the small portion of the mounting projection 56 to form a step. 56a, and further from above, the lid body 60 is fitted with the mounting hole 61 in the mounting projection 56, and the peripheral portion is superimposed on the notch step 59, and the lid body 60 is protruded from the mounting hole 61. The main body 52 and the lid body 60 are connected to each other by sandwiching a portion of the terminal portions 42 and 45 where the heat generating portions 43 and 46 are arranged, by a caulking portion 62 formed at the end.

The mounting projection 56 has the locking holes 44 and 47 and the mounting hole 61 fitted with almost no gap, and the terminal portions 42 and 45 are connected to the lower terminal portion 45 by an insulating material spacer 63 inserted therebetween. pedestal
The upper terminal portion 42 which is overlapped with 55 is sandwiched between the step portion 56a and the lid body 60 so as to be separated from each other, so that the heat generating portions 43 and 46 are respectively curved. Also, terminal section
42 and 45 are fixed to the protective case 51 without being moved by the mounting projection 56 penetrating and penetrating the window hole 57 without a gap in the width direction and partially projecting outward, and furthermore, the heat generating part 43,
46 is built in the protective case 51.

[Effects of the Invention] According to the present invention, a long and thin plate-like heat generating portion is integrally formed in a cantilever manner along a side edge of a terminal portion of a thin plate, and a free end of the heat generating portion is joined by a joint of a low melting point alloy. Since the fusible blocking piece is assembled to the protective case, the whole can be made thin and small, and can be installed in an extremely narrow space. In addition, since the melting time of the joint due to the overcurrent is determined by the volume of the heat-generating part, the composition of the joint, and the degree of curvature of the heat-generating part, it is possible to provide an arbitrary delay characteristic by appropriately selecting these. is there. Furthermore, since the heat generating portion is restored to a linear state by its own spring force when it is melted, the current is reliably cut off even if the terminal plate is approaching, thereby protecting the circuit.

In particular, according to the present invention, the heat-generating portion is housed in a protective case composed of a body and a lid made of an insulating material, and the terminal portion is fixed by using a mounting projection that couples the body and the lid.
With a very simple configuration, the fusible blocking piece can be assembled to the protective case, and since the heating section is fixed in a required curved state and shielded from the outside, it can be held stably without changing the characteristics. Alternatively, it can be handled without worrying that the joint may be damaged or broken by mistake during transportation or connection to a contact point of a circuit, and furthermore, dirt may adhere and cause malfunction.

[Brief description of the drawings]

1 to 4 show a first embodiment of the present invention, wherein FIG. 1 is an exploded perspective view, FIG. 2, FIG. 3, and FIG. 5 is a cross-sectional view along the line BB and CC, FIG. 5 is a front view showing an example of use of the first embodiment, and FIG. 6 is a process diagram of an example of manufacturing the fusible blocking piece of the first embodiment. It is. 7 to 9 show a second embodiment of the present invention, FIG. 9 is an exploded perspective view, and FIGS. 8 and 9 are FIGS. 7D-D line and EE line in an assembled state. FIG. 10 to 12 show a third embodiment of the present invention. FIG. 10 is an exploded perspective view, and FIGS. 11 and 12 show an assembled state.
10 is a cross-sectional view along the line FF and the line GG. 1, 41: Soluble blocking piece, 2, 5, 42, 45: Terminal part,
3, 6, 43, 46 ... heat-generating part, 4, 7, 44, 47 ... locking hole, 8, 48 ... joint, 11, 31, 51 ... protective case, 1
2, 32, 52: Body, 16, 38, 56: Mounting protrusion, 20, 3
5, 50 ... lid, 21, 34, 61 ... mounting holes,

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01H 85/36 H01H 69/02

Claims (1)

(57) [Claims] 1. A cantilevered heat-generating portion is integrally formed along a side edge of a plurality of terminal portions made of a springy metal thin plate in the form of an elongated plate, and a free end of the heat-generating portion is low. A fusible cut-off piece joined by a joining portion made of a melting point alloy and provided with a locking hole near the heat-generating portion of the terminal portion; a fusible cut-off piece comprising a main body and a lid made of an insulating material; A protective case in which a mounting projection is provided on one side of the body and a mounting hole is provided on the other side of the body, the mounting projection penetrating through the locking hole and the mounting hole to separate the terminal portions from each other. In addition, the main body and the lid are joined together with a part thereof interposed therebetween, and the heat generating portion is housed inside the protective case, and a part of the terminal portion projects outside the protective case. Soluble Cross-sectional device.