breaker

Abstract

To realize an optimal breaker for a SMD (surface mount device) by miniaturizing an outer shape while being arranged at a home position of a case by surely coupling an elastic arm plate with a terminal plate.SOLUTION: A breaker comprises: a fixed contact point metal plate 4 that includes a fixed contact point 5; an elastic arm plate 6 that includes a movable contact point 7; a terminal plate 3 that is formed by fixing the elastic arm plate 6; a case 1; and a bi-metal 8 that switches the movable contact point 7 from an On to an Off. The case 1 is made of a plastic, and provided with a hollow housing space 20 inside, and has connection terminals 4X and 3X arranged at each end part 1C of a bottom surface. The terminal plate 3 comprises a lower deposition plate 3A formed by deposing an upper deposition plate 6B in a lamination state via a laser welding part 30. The connection terminal 3X is coupled via a standing part 3B to a side edge of the lower deposition plate 3A extended in a width direction of the case 1. The standing part 3B is embedded into the case 1, and a lateral width (W1) of the lower deposition plate 3A is wider than a lateral width (W2) of the upper deposition plate 6B.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a breaker that detects temperature with a bimetal, which elastically deforms an elastic arm plate to separate a movable contact from a fixed contact and switch to the OFF state, and particularly to a breaker that is optimal for SMD (Surface Mount Device) that is mounted on a circuit board by methods such as reflow soldering. [Background technology]

[0002] Equipment such as battery packs and motors can improve safety by cutting off the current when the temperature becomes abnormally high. To achieve this, small micro breakers are used that switch off the contacts when a set temperature is reached. For example, a battery pack containing a lithium-ion battery can become hot when it is charged or discharged under abnormal usage conditions, so a small breaker is built in as a protection circuit to cut off the current at abnormally high temperatures to ensure safety. Also, motors and other devices can become abnormally hot when they are overloaded or when an abnormal current flows, so in this condition the breaker cuts off the current to protect the motor.

[0003] As a microbreaker for such applications, a breaker has been developed that detects temperature rise with a bimetal and separates the movable contact from the fixed contact to switch to the OFF state. A microbreaker detects temperature with a bimetal and separates the movable contact from the fixed contact to switch to the OFF state. When the temperature of this breaker exceeds a set temperature, the bimetal reverses, and the reversed bimetal deforms so as to push up the elastic arm plate that fixes the movable contact to its tip, and the movable contact is separated from the fixed contact to switch to the OFF state and cut off the current. When the temperature drops and the bimetal returns to its original shape, the elasticity of the elastic arm plate brings the movable contact into contact with the fixed contact and returns to the ON state. When the elastic arm plate is not pushed up by the bimetal, i.e., when the bimetal is not reversed by temperature, it elastically presses the movable contact against the fixed contact. That is, in this state, the movable contact is kept in contact with the fixed contact by the elasticity of the elastic arm plate and is maintained in the ON state.

[0004] The above microbreaker does not use a single metal plate for the elastic arm plate and the connection terminal, i.e., does not use an elastic metal arm plate that is pulled out of the case to use as a connection terminal, but uses a metal terminal plate with excellent conductivity for the connection terminal, and can be electrically connected to the circuit board in a suitable state. Since this microbreaker can be electrically connected by laser welding the elastic arm plate and the terminal plate, the applicant of the present application has developed an SMD (surface mount) breaker in which the elastic arm plate and the terminal plate are laser welded as a unique structure with the aim of laser welding in a suitable state (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2023-54993 A [Patent Document 2] JP 2018-206559 A Summary of the Invention [Problem to be solved by the invention]

[0006] Breaker 800 (microbreaker) described in Patent Document 1 shown in Fig. 18 has the advantage that elastic arm plate and terminal plate 803 can be firmly connected while being stably electrically connected by laser welding, but has the disadvantage that terminal plate 803 including the rising portion protrudes from the case, making the outer shape large, as shown in the figure. With the aim of reducing the outer shape, breaker 900 has been developed in which terminal plate 903 has a unique shape, as shown in Fig. 19 (Patent Document 2).

[0007] In the breaker 900 of Patent Document 2, an elastic arm plate 906 built into the case is connected to a terminal plate 903 inside the case, and a part of the terminal plate 903 is pulled out to the outside of the case to form a connection terminal. This structure has a drawback in that it is difficult to reliably and stably connect the elastic arm plate 906 and the terminal plate 903 by laser welding. This is because, as shown in the perspective view of FIG. 19 and the enlarged cross-sectional view of FIG. 20, the plastic 901 of the case is arranged on both sides of the terminal plate 903, so that the terminal plate 903 and the plastic 901 on both sides cannot be arranged on the same plane with high precision, and it is difficult to laminate the terminal plate 903 and the elastic arm plate 906 without any gaps. This is because the terminal plate 903, which is not arranged on the same plane as the surfaces of the plastic 901 on both sides, is difficult to stably and reliably adhere to the elastic arm plate 906 and the terminal plate 903 without any gaps in the laser welding process. In laser welding, it is important that the two metal plates to be welded are tightly attached to each other without any gaps, and even a small gap between the metal plates during the laser welding process can be a factor that hinders stable laser welding. Elastic arm plate 906 that is not reliably and stably welded to terminal plate 903 has the disadvantage that the movable contact and the fixed contact cannot always be in stable contact with each other with small contact resistance. Contacts with increased contact resistance have the disadvantage that the power loss in the ON state increases and the amount of heat generated by Joule heat also increases. Since the temperature rise caused by Joule heat causes the bimetal to reverse, there is also the disadvantage that in an environment where the ambient temperature is lower than the set temperature, the bimetal will reverse due to its own heat generation, causing the bimetal to switch to the OFF state.

[0008] The present invention was developed with the aim of further solving the above-mentioned shortcomings, and one of the objects of the present invention is to provide a breaker that is ideal for SMD (surface mount device), which can be compact in size while securely connecting the elastic arm plate and terminal plate and placing them in a fixed position in the case. [Means for solving the problem]

[0009] A breaker according to an embodiment of the present invention has all of the configurations (a) to (i). (a) The breaker has a fixed contact metal plate with a fixed contact, an elastic arm plate having a movable contact at its tip, the movable contact being disposed at a position opposite the fixed contact; a terminal plate having an upper welding plate provided at a rear end of the elastic arm plate and fixed via a laser welding portion; a plastic case in which a terminal board and a fixed contact metal plate are fixed; and a bimetal that presses the elastic arm plate to switch the movable contact from on to off. (b) The case is made of plastic; A hollow storage space is provided inside by arranging elastic arm plates. (c) The case is a connection terminal electrically connected to the fixed contact metal plate; A connection terminal electrically connected to the elastic arm plate is disposed at each end of the bottom surface. (d) The terminal board is The upper welding plate of the elastic arm plate exposed in the storage space of the case is welded in a stacked state to a lower welding plate. (e) The terminal board is On the side edge of the lower welding plate that extends in the width direction of the case, The connection terminals are connected via the rising portions. (f) The terminal board is A connection terminal connected to the lower welding plate via a rising portion, It is located at the edge of the bottom of the case. (g) The rising part is Through the case, It is embedded in the plastic of the case in a plane parallel to the width of the case, Place the lower welding plate in the storage space, The connection terminals are located on the bottom of the case. (h) The width (W1) of the lower welding plate is wider than the width (W2) of the upper welding plate. The upper and lower weld plates are in close contact with each other and connected by a laser welded portion. (i) The connection terminal is: It is disposed on the bottom surface of the case in a position extending vertically of the case from the connection with the rising portion toward the tip. Effect of the Invention

[0010] The above breakers have the advantage that they can be placed in fixed positions in the case by securely connecting the elastic arm plate and terminal board, while also achieving a compact external size, making them ideal for SMD (surface mount device). [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic perspective view of a breaker according to an embodiment of the present invention; [Diagram 2] 2 is a schematic perspective view of the breaker shown in FIG. 1, seen obliquely from below. [Diagram 3] FIG. 4 is a schematic perspective view of a terminal plate and a resilient arm plate. [Figure 4] 3 is a schematic plan view of a terminal plate and a fixed contact metal plate. FIG. [Diagram 5] 4 is a schematic plan view of a terminal plate, a fixed contact metal plate, and a resilient arm plate. FIG. [Figure 6] 6 is a schematic vertical sectional view taken along line VI-VI of the breaker shown in FIG. 1. [Figure 7] FIG. 2 is a schematic horizontal cross-sectional view of a breaker. [Figure 8] 10 is a schematic cross-sectional view showing an example of a laser welded portion where a terminal plate and a resilient arm plate are laser-welded. FIG. [Figure 9] FIG. 11 is a schematic cross-sectional view showing another example of a laser welded portion. [Figure 10] FIG. 11 is a schematic cross-sectional view showing another example of a laser welded portion. [Figure 11] 11 is a schematic vertical cross-sectional view showing another example of the rising portion. FIG. [Figure 12] 11 is a schematic cross-sectional view showing a state in which the terminal plate and the elastic arm plate are laser-welded together. FIG. [Figure 13] FIG. 11 is a schematic perspective view of a breaker according to another embodiment of the present invention, viewed obliquely from below. [Figure 14] FIG. 4 is a schematic perspective view of a terminal plate and a resilient arm plate. [Figure 15] 4 is a schematic plan view of a terminal plate, a fixed contact metal plate, and a resilient arm plate. FIG. [Figure 16] 3 is a schematic plan view of a terminal plate and a fixed contact metal plate. FIG. [Figure 17] 4 is a schematic perspective view of the terminal plate and the fixed contact metal plate, seen from an oblique downward direction. FIG. [Figure 18] FIG. 13 is a schematic perspective view of a breaker according to a conventional example. [Figure 19] FIG. 13 is a schematic perspective view of a terminal board and a resilient arm board according to a conventional example. [Figure 20] FIG. 11 is a schematic cross-sectional view of a breaker according to a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper", "lower", and other terms including these terms) are used as necessary, but the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meanings of these terms do not limit the technical scope of the present invention. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members. Furthermore, the embodiments shown below are specific examples of the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention. Furthermore, the contents described in one embodiment or example can be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0013] A breaker according to an embodiment of the present invention has all of the features (a) to (i). (a) The breaker has a fixed contact metal plate with a fixed contact, an elastic arm plate having a movable contact at its tip, the movable contact being disposed at a position opposite the fixed contact; a terminal plate having an upper welding plate provided at a rear end of the elastic arm plate and fixed via a laser welding portion; a plastic case in which a terminal board and a fixed contact metal plate are fixed; and a bimetal that presses the elastic arm plate to switch the movable contact from on to off. (b) The case is made of plastic; A hollow storage space is provided inside by arranging elastic arm plates. (c) The case is a connection terminal electrically connected to the fixed contact metal plate; A connection terminal electrically connected to the elastic arm plate is disposed at each end of the bottom surface. (d) The terminal board is The upper welding plate of the elastic arm plate exposed in the storage space of the case is welded in a stacked state to a lower welding plate. (e) The terminal board is On the side edge of the lower welding plate that extends in the width direction of the case, The connection terminals are connected via the rising portions. (f) The terminal board is A connection terminal connected to the lower welding plate via a rising portion, It is located at the edge of the bottom of the case. (g) The rising part is Through the case, It is embedded in the plastic of the case in a plane parallel to the width of the case, Place the lower welding plate in the storage space, The connection terminals are located on the bottom of the case. (h) The width (W1) of the lower welding plate is wider than the width (W2) of the upper welding plate. The upper and lower weld plates are in close contact with each other and connected by a laser welded portion. (i) The connection terminal is: It is disposed on the bottom surface of the case in a position extending vertically of the case from the connection with the rising portion toward the tip.

[0014] The above breakers have the advantage that they can reliably connect the elastic arm plate and terminal plate and place them in a fixed position in the case, while still allowing the external dimensions to be made compact and optimal for SMD (surface mount). The elastic arm plate and terminal plate can be reliably placed in a fixed position in the case because the terminal plate can be fixed in a fixed position in the case without misalignment, and the elastic arm plate can be reliably connected to this terminal plate by laser welding. The external dimensions can be made compact and optimal for SMD (surface mount) because the lower welding plate of the terminal plate is placed inside the case, the connection terminal is placed on the bottom surface outside the case, and the raised part connecting the lower welding plate and the connection terminal is embedded in the plastic of the case in a state that it penetrates the case.

[0015] Furthermore, the reason why the elastic arm plate and the terminal plate can be firmly connected is that the rising portions of the terminal plate are not provided at both ends of the lower welding plate as in conventional breakers, but are connected to the side edges of the lower welding plate, making the width (W1) of the lower welding plate wider than the width (W2) of the upper welding plate, and the upper welding plate of the elastic arm plate can be positioned inside the lower welding plate and laser welded. The upper welding plate, which is positioned inside the lower welding plate, can be fully attached to the surface of the lower welding plate without any gaps, so that in this state, a laser beam can be irradiated onto the surface of the upper welding plate to melt both the upper and lower welding plates in a tight contact state, providing a feature that the welding can be performed reliably.

[0016] A breaker according to another embodiment of the present invention has a structure including a pair of connection terminals in which terminal plates are spaced apart from each other, and the pair of connection terminals can be disposed at the corners of the bottom surface of the case.

[0017] In another embodiment of the invention, the breaker can form a laser weld into one or more linear weld lines.

[0018] Another embodiment of the breaker of the present invention allows for laser welding into one or more weld spots.

[0019] In another embodiment of the breaker of the present invention, the thickness of the elastic arm plate is 50 μm or more and 200 μm or less, and the breaker can be a micro breaker.

[0020] In another embodiment of the breaker of the present invention, the case has an outer peripheral wall in which a fixed contact metal plate and a terminal plate are embedded, and the inside of the outer peripheral wall is used as a storage space for placing an elastic arm plate, with an exposed portion in which the lower welding plate of the terminal plate is exposed within the storage space, and the terminal plate can be laser welded by stacking the upper welding plate of the elastic arm plate on the lower welding plate.

[0021] In another embodiment of the breaker of the present invention, the fixed contacts and the movable contacts can be activated contacts that are activated by ultrasonic vibration in a current-carrying state. (Embodiment 1)

[0022] The breaker 100 shown in Figures 1 to 12 below is an optimal breaker for SMD (surface mount device) mounted on a circuit board, and is mainly used built into a battery pack, etc. The breaker of the battery pack breaks the current by deforming the built-in bimetal when the battery or ambient temperature becomes high, or when the battery pack is used in an abnormal state. However, the present invention does not specify the use of the breaker, and can be used for breakers used in all applications that detect a temperature rise and cut off the current, such as in a motor, for example. (Breaker 100)

[0023] 1 to 12 show an SMD breaker 100. This breaker 100 includes a fixed contact metal plate 4 having a fixed contact 5, an elastic arm plate 6 with a movable contact 7 disposed at a position facing the fixed contact 5, a terminal plate 3 to which a rear end 6E of the elastic arm plate 6 is connected by a laser welding portion 30, a bimetal 8 for switching the elastic arm plate 6 on and off, and a case 1 in which the fixed contact 5 of the fixed contact metal plate 4 and the movable contact 7 of the elastic arm plate 6 are disposed and in which the bimetal 8 is disposed and the fixed contact metal plate 4 and the terminal plate 3 are fixed in position. When the ambient temperature of this breaker 100 rises to a high temperature, the bimetal 8 detects the temperature rise and deforms, and the deformed bimetal 8 presses the elastic arm plate 6 to separate the movable contact 7 from the fixed contact 5, switching the contact to the OFF state. Furthermore, when the ambient temperature drops to a predetermined temperature, the elastic arm plate 6 and the bimetal 8 return to their original positions, causing the movable contact 7 to come into contact with the fixed contact 5, switching the breaker 100 to the ON state.

[0024] 1 to 7, a terminal plate 3 connecting a fixed contact metal plate 4 and a resilient arm plate 6 is fixed to a plastic case 1, and a bimetal 8 that deforms the resilient arm plate 6 and a heater 9 that heats the bimetal 8 are built in under the resilient arm plate 6. The breaker 100 in Fig. 6 has a built-in heater 9 that heats the bimetal 8, making it ideal for applications in which the bimetal 8 is heated by the heater 9 to maintain a current interrupted state. (Case 1)

[0025] The case 1 has the connection terminals 3X and 4X arranged at each end 1C of the case 1 in the vertical direction (V) on the bottom surface. In the case 1 of FIG. 1 and FIG. 2, the connection terminal 4X is arranged at one end 1C of the bottom surface of the case 1, and the connection terminal 3X is arranged at the other end 1C of the bottom surface of the case 1. The bottom surface of the case 1 is the bottom surface of the case 1 as shown in FIG. 1 and FIG. 2, and is the surface on which the connection terminals 3X and 4X are arranged. The connection terminals 3X and 4X can be arranged on the whole or part of either one of the ends 1C, and can be arranged at the corners 1D of the end 1C of the bottom surface of the case 1. The corners 1D indicate the range from the center to the corners of each end 1C of the bottom surface. The case 1 of the figure has the connection terminals 3X and 4X arranged at the corners 1D (four corners) of each end 1C of the bottom surface. The connection terminals 3X and 4X arranged at the corners 1D of the bottom surface of the case 1 are electrically connected to the fixed contact metal plate 4 by a pair of connection terminals 4X arranged at one end 1C in the vertical direction (V) of the case 1, and electrically connected to the elastic arm plate 6 via the terminal plate 3 by a pair of connection terminals 3X arranged at the other end 1C. The case 1 in FIG. 6 is made of plastic and comprises a main case 1A and a lid case 1B. The lid case 1B is connected to the main case 1A to provide a storage space 20 inside. The case 1 has the fixed contact metal plate 4 and the terminal plate 3 inserted into the main case 1A and fixed in place, and the lid case 1B is fixed to the top surface. The main case 1A has a first outer wall 11A and a second outer wall 11B protruding from both ends, and a storage space 20 is provided between the first outer wall 11A and the second outer wall 11B. 6, the case 1 has a fixed contact metal plate 4 disposed on the bottom surface of a storage space 20 provided in a main case 1A, and a cover case 1B closes the top surface of the storage space 20. In the case 1 of FIGS. 1 and 2, the longitudinal direction is the vertical direction (V) and the transverse direction is the width direction (W). (Main case 1A)

[0026] The main body case 1A has an outer peripheral wall 10 around the storage space 20. The outer peripheral wall 10 has an outer wall 11 consisting of a first outer wall 11A and a second outer wall 11B, and an opposing wall 12 connecting both ends of the first outer wall 11A and the second outer wall 11B, and the opposing wall 12 and the outer wall 11 are provided around the storage space 20. The main body case 1A surrounds the storage space 20 with the outer peripheral wall 10, and closes the bottom and top of the outer peripheral wall 10. The bottom of the storage space 20 is closed by a bottom part 13 and a fixed contact metal plate 4 that are integrally formed with the main body case 1A, and the top is closed by a cover case 1B that is connected to the main body case 1A, making the storage space 20 a closed hollow space.

[0027] The fixed contact metal plate 4 and the terminal plate 3 are fixed to the main case 1A by insert molding. The main case 1A has a part of the fixed contact metal plate 4 embedded in the first outer wall 11A. In Fig. 6 and Fig. 7, the fixed contact metal plate 4 is fixed to the main case 1A by insert molding so that the middle part 4B is embedded halfway in the first outer wall 11A. The fixed contact metal plate 4 is fixed to the main case 1A in a state where it penetrates the first outer wall 11A, and the fixed contact 5 is provided on the part exposed inside the storage space 20, and the part drawn out to the outside is the connection terminal 4X.

[0028] The terminal plate 3 is fixed to the main case 1A by insert molding. The terminal plate 3 is formed by cutting a single metal plate and then bending it to a shape in which a pair of connection terminals 3X are connected to the side edges of the lower welding plate 3A via rising portions 3B. The main case 1A has the rising portions 3B of the terminal plate 3 embedded in the plastic of the case 1, the lower welding plate 3A exposed to the storage space 20, and the pair of connection terminals 3X are disposed on both sides of the bottom surface 13 of the case 1. The upper welding plate 6B of the elastic arm plate 6 is laminated on the lower welding plate 3A exposed to the storage space 20, and the two are connected in a state in which they are in close contact with each other and electrically connected by the laser welding portion 30.

[0029] The entire surface of the lower welding plate 3A of the terminal board 3 can be exposed to the storage space 20, and the upper welding plate 6B of the elastic arm plate 6 can be laminated on the exposed portion 3a and connected by the laser welding portion 30, or a part of the lower welding plate 3A, for example both ends, can be embedded in the plastic of the case 1. In this state, the terminal board 3 fixed to the main case 1A by insert molding can be connected by laminating the upper welding plate 6B on the exposed portion 3a of the lower welding plate 3A and laser welding it. The terminal board 3 fixed to the case 1 by embedding both ends of the lower welding plate 3A in the case 1 can be fixed in a fixed position of the case 1 without any positional deviation, and the upper welding plate 6B can be laminated on the lower welding plate 3A exposed to the storage space 20 and laser welded.

[0030] The fixed contact metal plate 4 is insert-molded and placed in a fixed position in the main case 1A, so the fixed contact 5 is placed in a fixed position in the case 1 via the fixed contact metal plate 4. The terminal plate 3 is also insert-molded and placed in a fixed position in the main case 1A, and the elastic arm plate 6 is connected to the terminal plate 3, so the movable contact 7 is placed in a fixed position in the case 1 via the elastic arm plate 6. The main case 1A, which places the fixed contact 5 and the movable contact 7 in a fixed position with this structure, has the feature of being able to prevent the contact position between the movable contact 7 and the fixed contact 5 from shifting. The movable contact 7 is connected to the main case 1A via the elastically deformable elastic arm plate 6, so that the elastic arm plate 6 and the terminal plate 3 are reliably connected, and the relative positional shift with respect to the fixed contact 5 can be prevented. The relative positional shift of the connection position between the terminal plate 3, which is fixed in a fixed position in the main case 1A, and the elastic arm plate 6 causes the positional shift of the movable contact 7, which causes the relative positional shift of the movable contact 7 and the fixed contact 5. The relative positional deviation between the fixed contact 5 and the movable contact 7 causes an increase in the contact resistance between the reciprocating movable contact 7 and the fixed contact 5.

[0031] 6, the upper welding plate 6B of the elastic arm plate 6 is connected to the main case 1A by a fitting structure and placed in a fixed position. The main case 1A of this structure has the feature that the elastic arm plate 6 is placed in a fixed position by a fitting structure, and the upper welding plate 6B is laser welded to the lower welding plate 3A of the terminal board 3, so that it can be placed in the fixed position without misalignment.

[0032] Furthermore, the main body case 1A shown in the cross-sectional view of Fig. 6 is provided with a storage recess 29 in which the heater 9 is placed in the storage space 20. The storage recess 29 is located in the center of the storage space 20, and its bottom surface is closed by the tip portion 4A of the fixed contact metal plate 4. The storage recess 29 has an inner shape slightly larger than the outer shape of the heater 9 so that the heater 9 can be inserted therein. The storage recess 29 also has a protruding portion 19 along its outer periphery. The heater 9 inserted into the storage recess 29 protrudes slightly from the upper surface of the protruding portion 19, and has a curved bimetal 8 placed on its upper surface in a thermally coupled state.

[0033] In the storage space 20, the bottom surface of the storage recess 29 is closed by the fixed contact metal plate 4, and the outer bottom surface of the storage recess 29 is closed by the plastic of the main body case 1A. The main body case 1A has the fixed contact metal plate 4 insert-molded into the plastic bottom 13 that closes the bottom of the storage space 20 on the outside of the storage recess 29, and is fixed to the main body case 1A. (Lid case 1B)

[0034] As shown in FIG. 6, the lid case 1B is disposed on the opening side of the main case 1A in a state of covering the upper side of the elastic arm plate 6. The lid case 1B shown in the figure is made of plastic, and is fixed to the main case 1A by fixing its outer peripheral edge to the upper surface of the outer peripheral wall 10 of the main case 1A. As shown in FIG. 6 and FIG. 7, the lid case 1B has an outer peripheral wall 22 that protrudes toward the main case 1A at its outer peripheral edge facing the outer peripheral wall 10 of the main case 1A, and the inside of this outer peripheral wall 22 is formed into a recessed shape with a downward opening to serve as a storage section 23 for storing the elastic arm plate 6 that is elastically deformed when pressed by the bimetal 8. The outer peripheral wall 22 of the lid case 1B is fixed to the first outer wall 11A and the second outer wall 11B provided at both ends of the main case 1A, and is further fixed to the opposing wall 12. The plastic lid case 1B is connected to the main case 1A by ultrasonic welding.

[0035] The case 1 shown in Figs. 6 and 7 has a connecting protrusion 17 and a connecting recess 18 that fit together to connect the lid case 1B and the main case 1A while accurately positioning them. The lid case 1B shown in Fig. 6 has connecting protrusions 17 that protrude from the lower surface of the outer peripheral wall 22 toward the main case 1A on both sides of the end of the main case 1A on the first outer wall 11A side. As shown in Fig. 6, the main case 1A has connecting recesses 18 that guide the connecting protrusions 17 on the upper surface of the outer peripheral wall 10 that faces these connecting protrusions 17. Furthermore, the lid case 1B shown in Fig. 6 has a fitting protrusion 16 that fits into the open end of the recess 21 provided on the second outer wall 11B side of the main case 1A and is arranged on the upper surface of the laminated portion 40 of the elastic arm plate 6. The outer shape of this mating convex portion 16 is similar to the planar shape of the recess 21 and is shaped to fit into a step recess 24 formed on the upper surface side of the upper welding plate 6B of the elastic arm plate 6 inserted into the recess 21.

[0036] In the above case 1, at the end portion on the first outer wall 11A side of the main case 1A, the connecting protrusions 17 on both sides of the lid case 1B are guided into the connecting recesses 18 of the main case 1A, and at the end portion on the second outer wall 11B side of the main case 1A, the mating protrusions 16 of the lid case 1B are guided into the step recesses 24 formed on the upper surface side of the laminated portion 40 of the elastic arm plate 6, so that the lid case 1B is connected to the main case 1A in an accurate position. (Fixed contact metal plate 4)

[0037] The fixed contact metal plate 4 is fixed to the main body case 1A by insert molding. The fixed contact metal plate 4 in Fig. 6 has a front end portion 4A that closes the opening of the bottom 13 of the storage space 20, a rear end portion 4C having a connection terminal 4X, and an intermediate portion 4B between the front end portion 4A and the rear end portion 4C. The fixed contact metal plate 4 shown in the cross-sectional view of Fig. 6 closes the opening of the bottom 13 of the storage space 20 with the front end portion 4A, and is fixed to the main body case 1A by insert molding so that parts of the intermediate portion 4B and the rear end portion 4C are embedded from the bottom 13 of the storage space 20 to the first outer wall 11A of the main body case 1A. The fixed contact metal plate 4 in Figures 6 and 7 has a step portion 4D so that the portion embedded in the first outer wall 11A is higher than the portion blocking the opening of the bottom 13 of the storage space 20, and the step portion 4D is embedded in the bottom 13 of the main body case 1A with a part of the step portion 4D exposed on the upper surface of the bottom 13, and this exposed portion is used as the fixed contact 5.

[0038] The fixed contact metal plate 4 can be formed into the fixed contact 5 by pressing a silver inlay material into the metal plate. The metal plate of the fixed contact 5 is copper or a copper alloy, or nickel or a nickel alloy. The inlay material can be made thicker to extend the life of the contact, so the thickness is set to 200 μm. However, the surface of the fixed contact metal plate 4 can be silver-plated to form the silver-plated layer into the fixed contact 5. The silver-plated layer of the fixed contact 5 is thicker than the silver-plated layer 37 of the movable contact 7, for example, 6 μm. However, the film thickness of the silver-plated layer of the fixed contact 5 can be set to 5 μm to 100 μm, preferably 3 μm to 50 μm, and can be thicker than the movable contact 7. By making the silver-plated layer of the fixed contact 5 thicker, the fixed contact 5 can be connected to a polarity that is easily damaged, thereby extending the life of the connection.

[0039] The fixed contact metal plate 4 is provided with a connection terminal 4X on the rear end 4C side. The fixed contact metal plate 4 in FIG. 4 to FIG. 7 is provided with a pair of connection terminals 4X arranged apart from each other. As shown in FIG. 1 and FIG. 2, the pair of connection terminals 4X are arranged at the corners of the bottom surface of the case 1. The connection terminal 4X of the fixed contact metal plate 4 is bent so that the rear end 4C side drawn out from the case 1 is positioned almost flush with the bottom surface of the case 1, i.e., the bottom surface of the main case 1A, so that it can be fixed to the surface of the circuit board by soldering such as reflow soldering. This breaker 100 is heated and reflow soldered with the connection terminal 4X arranged on the solder surface of the circuit board. However, the breaker can also be provided with an exposed portion of the fixed contact metal plate 4 exposed from the surface on the bottom side of the insulating case as an exposed terminal 44, and this exposed terminal 44 can be reflow soldered to the solder surface of the circuit board. This breaker can be fixed by soldering the exposed terminal 44 of the fixed contact metal plate 4 to the surface of a circuit board or the like, without necessarily drawing out the connection terminal 4X from the case 1 to the outside. (Elastic arm plate 6)

[0040] The elastic arm plate 6 shown in Figs. 3, 5 to 7 has a movable contact 7 at a position facing the fixed contact 5 at a tip end 6D, and an upper welding plate 6B at a rear end 6E. The upper welding plate 6B is laminated on the lower welding plate 3A of the terminal plate 3 and fixed to the terminal plate 3 by a laser welding part 30, and the movable part 6A at the middle part is disposed inside the storage space 20. The elastic arm plate 6 is made of a conductive metal plate that can be elastically deformed. The metal plate of the elastic arm plate 6 can be a Cu-Cr-Ag-Si alloy. The Cu-Cr-Ag-Si alloy contains 0.01 to 5 wt%, preferably 0.01 to 2.5 wt%, 0.01 to 5 wt%, preferably 0.01 to 2.5 wt%, 0.01 to 5 wt%, preferably 0.01 to 2.5 wt%, Ag, and 0.01 to 5 wt%, preferably 0.01 to 2.5 wt%, Si, in the base Cu. Furthermore, the elastic arm plate 6 may be made of elastic metal plates such as a copper alloy containing Ni, P, Zn, and Fe, a copper alloy containing Fe, P, and Zn, a copper alloy containing Cr and Mg and having an IACS of 75% to 95%, a copper alloy containing Zr and having an IACS of 80% to 95%, or a copper alloy containing Sn and having an IACS of 80% to 95%. However, IACS [international annealed copper standard] is an internationally adopted standard for electrical resistance or electrical conductivity, which is annealed standard soft copper (volume resistivity is 1.7241 x 10 -2 This notation defines conductivity in μΩm as 100%.

[0041] Furthermore, the elastic arm plate 6 has a movable contact 7 on the tip 6D of the movable part 6A, which faces the fixed contact 5. The movable contact 7 of the elastic arm plate 6 has a silver-plated layer on the area facing the fixed contact 5, which reduces the contact resistance with the fixed contact 5. When the bimetal 8 is not thermally deformed, the elastic arm plate 6 has the movable contact 7 in contact with the fixed contact 5 to be in the ON state, and when the bimetal 8 is thermally deformed, the movable part 6A pressed by the bimetal 8 is elastically deformed, and the movable contact 7 is separated from the fixed contact 5 to be in the OFF state. In the non-energized type breaker 100 shown in FIG. 6, a pressing protrusion 25 that presses the rear end 6E side of the movable part 6A downward is provided protruding from the inner surface of the cover case 1B so that the movable contact 7 can be reliably brought into contact with the fixed contact 5 when the bimetal 8 is not thermally deformed. When the rear end 6E side of the movable part 6A of this elastic arm plate 6 is pressed downward by the pressing protrusion 25, the tip 6D of the movable part 6A is forced downward, thereby ensuring that the movable contact 7 at the tip comes into contact with the fixed contact 5.

[0042] Furthermore, the breaker 100 can be provided with a deformation limiting protrusion 26 on the cover case 1B. The deformation limiting protrusion 26 is located at a position where it presses the tip 6D of the movable part 6A, i.e., the movable contact 7 side, downward, and by protruding toward the movable part 6A side, it can limit the amount of deformation of the movable part 6A of the elastic arm plate 6 when the bimetal 8 is thermally deformed and the movable contact 7 is separated from the fixed contact 5 in the OFF state. This breaker 100 can limit the amount of deformation of the movable part 6A when the movable part 6A is pushed up by the inverted bimetal 8 by pressing the tip 6D of the movable part 6A downward, i.e., toward the fixed contact 5, with the deformation limiting protrusion 26. Therefore, the breaker 100 with this structure has the feature that it can prevent the inverted bimetal 8 from pushing up the movable part 6A of the elastic arm plate 6 beyond its elastic limit and reducing its springiness, and can press the movable contact 7 against the fixed contact 5 with a predetermined contact pressure after recovery, thereby keeping the contact resistance small.

[0043] Furthermore, the elastic arm plate 6 has a protrusion 6C on its underside, and both ends of the bimetal 8 come into contact with this protrusion 6C to press against each other. The protrusion 6C shown in FIG. 6 has an arc-shaped outer shape, which allows both ends of the bimetal 8 to reliably come into contact and press against each other without sliding laterally. The elastic arm plate 6 shown in the figure has multiple protrusions 6C on its underside that face both ends of the bimetal 8. This structure allows even wide bimetal 8 to reliably come into contact and press against each other. (Terminal board 3)

[0044] The terminal plate 3 shown in Figs. 3 to 7 is a metal plate with excellent conductivity, which is fixed to the main case 1A, and the elastic arm plate 6 connected by the laser welding portion 30 is arranged at a fixed position on the case 1. The terminal plate 3 is fixed at a fixed position by insert molding and partially embedding it in the main case 1A. The terminal plate 3 includes a lower welding plate 3A extending in the width direction of the case 1, a rising portion 3B connected to the lower welding plate 3A, and a connection terminal 3X connected to the rising portion 3B. The terminal plate 3 includes a lower welding plate 3A extending in the inner direction of the case 1 on the upper end side of the rising portion 3B, and a connection terminal 3X extending in the outer edge direction of the case 1 on the lower end side of the rising portion 3B. As shown in Fig. 3, the rising portion 3B is arranged in a substantially vertical direction, and the lower welding plate 3A and the connection terminal 3X are arranged in a horizontal direction. The terminal plate 3 in Fig. 3 has a pair of connection terminals 3X connected to both ends of the side edge of the lower welding plate 3A via the rising portion 3B. A pair of connection terminals 3X in Fig. 3 are connected to both ends of a rising portion 3B extending in the width direction of the case 1, and are arranged in a corner portion 1D of the bottom surface of the case 1. The pair of connection terminals 3X are arranged at one end portion 1C of the bottom surface of the case 1 in a position extending in the vertical direction (V) of the case 1 from the connection portion with the rising portion 3B toward the tip of the connection terminal 3X. The lower welding plate 3A in Fig. 6 has its upper surface exposed to the storage space 20 of the case 1, and is connected to an upper welding plate 6B of the elastic arm plate 6. The upper welding plate 6B of the elastic arm plate 6 is laminated on the surface of the exposed portion 3a of the lower welding plate 3A, and is connected to the lower welding plate 3A by a laser welding portion 30.

[0045] The lower weld plate 3A and the upper weld plate 6B are laser welded together in the following process. (1) The upper welding plate 6B of the elastic arm plate 6 is laminated on the surface of the lower welding plate 3A. (2) The upper welding plate 6B is pressed against the lower welding plate 3A so that the upper welding plate 6B is brought into close contact with the surface of the lower welding plate 3A without any gaps. (3) With the upper weld plate 6B in close contact with the lower weld plate 3A, a laser beam is irradiated onto the surface of the upper weld plate 6B to melt and weld both the upper weld plate 6B and the lower weld plate 3A with the laser beam.

[0046] The lower welding plate 3A of the terminal board 3 connects a pair of connection terminals 3X to both ends of the side edge extending in the width direction (W) of the case 1 via rising portions 3B. The pair of connection terminals 3X connected to both ends of the lower welding plate 3A via the rising portions 3B are arranged at one end 1C (corner portion 1D) of the bottom surface of the case 1. The rising portions 3B penetrate the case 1 and arrange the pair of connection terminals 3X on the bottom surface of the case 1. The rising portions 3B are embedded in the plastic of the case 1 in a position parallel to the width direction (W) of the case 1, and the lower welding plate 3A is arranged in the storage space 20, and the connection terminals 3X are arranged on the bottom surface of the case 1.

[0047] The laser welding section 30 melts both the upper welding plate 6B and the lower welding plate 3A and welds them reliably by stacking two metal plates without gaps and irradiating them with a laser beam. In laser welding, it is important to bring the two metal plates into close contact with each other without gaps at the timing of irradiating the laser beam. A gap that occurs between the two metal plates when irradiating the laser beam becomes a factor that hinders stable welding of the two metal plates. In order to allow the upper welding plate 6B to be in close contact with the lower welding plate 3A without gaps when irradiating the laser beam, the width (W1) of the lower welding plate 3A is set to be equal to or larger than the width (W2) of the upper welding plate 6B, and the upper welding plate 6B is disposed inside the lower welding plate 3A, so that the entire surface of the upper welding plate 6B can be in close contact with the surface of the lower welding plate 3A. The upper welding plate 6B stacked inside the lower welding plate 3A can be pressed from the surface to be in close contact with the entire surface of the lower welding plate 3A. In this state, a laser beam is irradiated onto the surface of the upper welding plate 6B, melting both the upper welding plate 6B and the lower welding plate 3A, which are in close contact with each other. In this state, the upper welding plate 6B and the lower welding plate 3A are securely welded together, and the elastic arm plate 6 and the terminal plate 3 are securely connected in an electrically connected state.

[0048] Furthermore, in the breaker 100 shown in FIG. 1, the rising portion 3B is arranged in a specific position so that the terminal board 3 is reliably fixed to the case 1 while keeping the outer shape compact, and the upper welding plate 6B is reliably laser-welded to the lower welding plate 3A. The rising portion 3B is connected to the side edge of the lower welding plate 3A extending in the width direction (W) of the case 1 (the left side edge of the lower welding plate 3A in FIG. 3), and is embedded in the case 1 as shown in FIG. 6, so that the terminal board 3 is arranged in a fixed position in the case 1. The rising portion 3B embedded in the plastic of the case 1 is arranged in the storage space 20 of the case 1 with the lower welding plate 3A connected to the upper end in FIG. 3, and a pair of connection terminals 3X is arranged in the corners 1D on both sides of the bottom surface of the case 1. The pair of connection terminals 3X arranged in the corners 1D of the bottom surface of the case 1 are fixed to one end 1C of the bottom surface in an orientation extending in the vertical direction (V) of the case 1 from the connection portion with the rising portion 3B toward the tip.

[0049] In the terminal board 3 in Fig. 3, the angle (α) between the rising portion 3B and the lower welding plate 3A is approximately a right angle (within 90°±15°), and the angle (β) between the rising portion 3B and the connection terminal 3X is also approximately a right angle (within 90°±15°), and the rising portion 3B is embedded in the plastic of the case 1 in an approximately vertical position. However, as shown in Fig. 11, the angle (α) between the rising portion 3B and the lower welding plate 3A and the angle (β) between the rising portion 3B and the connection terminal 3X are acute angles, which is a feature that the connection terminal 3X can be made long while keeping the external shape compact. In addition, this structure can also realize the feature that the terminal board 3 can be fixed more firmly to the case 1 by embedding the longer rising portion 3B in the plastic of the case 1 in an inclined position. In addition, the angle (α) between the rising portion 3B and the lower welding plate 3A and the angle (β) between the rising portion 3B and the connection terminal 3X can also be obtuse angles. The above terminal board 3 can be formed by cutting a single metal plate and then bending it to have the lower weld plate 3A, the rising portion 3B, and the connection terminal 3X.

[0050] The structure in which the connection terminal 3X is disposed on the bottom surface of the case 1 via the rising portion 3B can be used as an SMD (surface mount) breaker by arranging the connection terminal 3X on approximately the same plane as the bottom surface of the case 1 and connecting and fixing it to the solder surface of the circuit board by a method such as reflow soldering. (Laser welded part 30)

[0051] The laser welded portion 30 reliably welds the upper weld plate 6B and the lower weld plate 3A, and positions the movable contact 7 and the fixed contact 5 in fixed positions, preventing the contact positions from shifting. Since a microbreaker uses an extremely thin metal plate for the elastic arm plate 6, the contact pressure of the contacts is quite small at 10g or less, so it is particularly important to keep the contact resistance small. An increase in contact resistance causes an increase in Joule heat due to current, which causes damage to the contacts and the contact resistance to increase exponentially, and also causes various problems such as thermal deformation of the plastic case 1.

[0052] The laser welding portion 30 can be reliably welded by preferably irradiating a fiber laser beam to melt both the upper welding plate 6B and the lower welding plate 3A of the elastic arm plate 6. The upper welding plate 6B and the lower welding plate 3A can be stacked in a tightly contacted state without any gaps and irradiated with a laser beam to be reliably welded. A gap generated between the upper welding plate 6B and the lower welding plate 3A at the timing of irradiating the laser beam inhibits the stability of the welded state of the laser welding portion 30. In order to tightly contact the upper welding plate 6B and the lower welding plate 3A without any gaps, as shown in FIG. 12, the surface of the upper welding plate 6B of the elastic arm plate 6 is pressed by a pusher 51 to be laser welded. As shown in the figure, the pusher 51 can press the vicinity of the laser welding portion 30 irradiated with the laser beam, for example, both sides and the periphery of the laser welding portion 30, to tightly contact the upper welding plate 6B with the surface of the lower welding plate 3A.

[0053] The upper welded plate 6B and the lower welded plate 3A are arranged in close contact with each other. The width (W1) of the lower welded plate 3A is made larger than the width (W2) of the upper welded plate 6B, so that the entire upper welded plate 6B can be in close contact with the surface of the lower welded plate 3A.

[0054] In the case 1 shown in the cross-sectional view of FIG. 12, a bottom plate 15 is provided on the back surface of the lower welding plate 3A of the terminal board 3 so that the upper welding plate 6B of the elastic arm plate 6 is in close contact with the surface of the lower welding plate 3A of the terminal board 3 when the upper welding plate 6B of the elastic arm plate 6 is pressed by the pusher 51. The bottom plate 15 is integrally formed with the main case 1A in a state where it is in close contact with the terminal board 3. In this breaker 100, when the elastic arm plate 6 is pressed by the pusher 51, the bottom plate 15 supports the lower surface of the terminal board 3 and makes the elastic arm plate 6 in close contact with the surface of the terminal board 3. In this breaker 100, in the process of welding the elastic arm plate 6 to the terminal board 3, the case 1 is placed on a flat base plate 52 and the elastic arm plate 6 is pressed to make it in close contact with the terminal board 3. When the elastic arm plate 6 is pressed by the pusher 51, the terminal board 3 is supported by the base plate 52 via the bottom plate 15. Therefore, when the pusher 51 presses the elastic arm plate 6, the laminated elastic arm plate 6 and the terminal plate 3 are sandwiched between the pusher 51 and the bottom plate 15 and tightly adhere to each other. The breaker 100 having this structure has the advantage that it can be mass-produced efficiently because the main case 1A is placed on the flat base plate 52, the elastic arm plate 6 is pressed against the terminal plate 3, and laser welding is performed. This is because it is not necessary to adjust the position where the main case 1A is set on the base plate 52 with high precision. Furthermore, in this structure, when the pusher 51 presses the elastic arm plate 6, the thermoplastic bottom plate 15 acts as a buffer layer. Therefore, the bottom plate 15 absorbs the error in the pressing position of the pusher 51, and the pressing force between the elastic arm plate 6 and the terminal plate 3 can be adjusted to an optimal state.

[0055] 12, an opening 15A is provided in bottom plate 15, and a support rib 53 that directly supports the lower surface of terminal board 3 is provided protruding from base plate 52. Opening 15A in bottom plate 15 is located on the lower surface of lower welding plate 3A of terminal board 3. This main case 1A is set in a fixed position on base plate 52 with support rib 53 guided to opening 15A. With support rib 53 supporting the lower surface of terminal board 3, elastic arm plate 6 stacked on terminal board 3 is pressed by pusher 51, and elastic arm plate 6 and terminal board 3 are closely attached and laser welded.

[0056] The elastic arm plate 6, which has the movable contact 7 fixed to its tip, has the upper welding plate 6B connected to the terminal plate 3 by laser welding. Laser welding involves locally irradiating a laser beam to melt and spot weld the elastic arm plate 6 and the terminal plate 3. The elastic arm plate 6 connected to the terminal plate 3 by spot welding is pushed by the reversing bimetal 8 to switch to the OFF state, and the bimetal 8 returns to its original state to switch to the ON state. The elastic arm plate 6 is switched to the OFF state by moving the movable contact 7 away from the fixed contact 5, and to the ON state by contacting the fixed contact 5. However, since the movable contact 7 is provided at the tip and the upper welding plate 6B is fixed to the terminal plate 3, a slight positional deviation of the upper welding plate 6B increases the positional deviation of the movable contact 7 at the tip. Therefore, a slight positional deviation of the upper welding plate 6B of the elastic arm plate 6 causes the contact position of the movable contact 7 and the fixed contact 5 to shift. A slight deviation in the contact position of the movable contact 7 and the fixed contact 5 causes a change in contact resistance. With the elastic arm plate 6 that is locally spot-welded, it is difficult to prevent the contact position from shifting over a long period of time when the movable contact 7 is reciprocated.

[0057] Furthermore, in laser welding, various external conditions such as temperature and surface condition cause the welding condition to fluctuate, so it is difficult to reliably connect the elastic arm plate 6 and the terminal plate 3 and reliably prevent the contact position of the contact from shifting in all mass-produced breakers. Furthermore, the bimetal 8 reverses instantly when the ambient temperature reaches the set temperature, and returns instantly when the ambient temperature drops to the return temperature, giving an impact to the elastic arm plate 6, which also makes it difficult to reliably fix the elastic arm plate 6 to the terminal plate 3 for a long period of time. In addition, in a micro breaker, which is extremely small as a whole, the contact resistance increases even with a slight shift in the contact position of the contact. This is because the contact pressure between the movable contact 7 and the fixed contact 5 is weak, and the movable contact 7 and the fixed contact 5 are in contact with each other in an extremely narrow local area in the on state. Furthermore, the surfaces of the movable contact 7 and the fixed contact 5 of the breaker are not always kept in a uniform state over the entire surface, and the contact resistance of the surfaces of the non-contact positions where they are not in constant contact increases due to a thin oxide film, etc., compared to the positions where they are in constant contact.

[0058] Microbreakers use an activation process to reduce the contact resistance of the contacts. The contact activation process involves ultrasonically vibrating the contacts while they are energized in the on state. Contacts activated in this way have low contact resistance only when the movable contact 7 and fixed contact 5 are in contact at a specific position, so if the contact position of the contacts shifts, the contact resistance increases.

[0059] 8 to 10 show examples of laser welded parts 30 that fix the elastic arm plate 6 to the terminal plate 3 while preventing misalignment of the elastic arm plate 6. The upper and lower welded plates can be connected by laser welding at the laser welded parts 30. The laser welded parts 30 can be welded at one or more weld spots 32 (FIG. 8), or at one or more elongated weld lines 31 extending linearly (FIGS. 9 and 10), or alternatively, at both the linear weld line 31 and the multiple weld spots 32.

[0060] In the laser welded portion 30 in FIG. 8, multiple welding spots 32 are arranged at intervals in the width direction (W), which is the short side direction of the elastic arm plate 6. In the laser welded portion 30 in FIG. 8, the welding spots 32 are provided at three locations at intervals in the width direction (W) of the elastic arm plate 6, but two or four or more welding spots 32 may be provided. In the laser welded portion 30 in this figure, multiple welding spots 32 are provided at intervals in the width direction (W) of the elastic arm plate 6, so that when the elastic arm plate 6 is in a state of elastic deformation, the region extending in the width direction (W) of the laminated portion 40 of the elastic arm plate 6 can be tightly attached to the terminal plate 3. This prevents the contact positions of the movable contact 7 and the fixed contact 5 from shifting in the width direction (W), and stabilizes the contact pressure of the contacts. Furthermore, the multiple welding spots 32 can be arranged at intervals in the vertical direction (V) which is the longitudinal direction of the elastic arm plate 6, and the region extending in the longitudinal direction of the elastic arm plate 6 can be brought into close contact with the terminal plate 3, preventing deviation of the contact position between the movable contact 7 and the fixed contact 5 and stabilizing the contact pressure of the contacts. Furthermore, the laser welded portion 30 can arrange the multiple welding spots 32 at intervals in the vertical direction (V) and width direction (W) of the elastic arm plate 6, and the region extending in both the longitudinal direction and lateral direction of the elastic arm plate 6 can be brought into close contact with the terminal plate 3, reliably preventing deviation of the contact position between the movable contact 7 and the fixed contact 5 in both the longitudinal direction and lateral direction.

[0061] In the laser welded portion 30 in FIG. 9, the linearly extending weld line 31 is a horizontal weld line portion 31B extending in the width direction (W) which is the short side direction of the elastic arm plate 6. In this figure, the horizontal weld line portion 31B is a straight line parallel to the width direction (W) of the elastic arm plate 6, but the horizontal weld line portion 31B can be a straight line extending in a direction inclined with respect to the width direction (W) of the elastic arm plate 6, or a curved line. Since the horizontal weld line portion 31B extends in the width direction (W) which is the short side direction of the elastic arm plate 6, when the elastic arm plate 6 is elastically deformed in the width direction (W), the region extending in the width direction (W) of the laminated portion 40 of the elastic arm plate 6 can be tightly attached to the terminal plate 3. This prevents the contact position of the movable contact 7 and the fixed contact 5 from shifting in the width direction (W), and stabilizes the contact pressure of the contacts.

[0062] In the laser welded portion 30 in FIG. 10, the linearly extending weld line 31 is a vertical weld line portion 31A extending in the vertical direction (V) which is the longitudinal direction of the elastic arm plate 6. The vertical weld line portion 31A in this figure is a straight line parallel to the vertical direction (V) of the elastic arm plate 6, but the vertical weld line portion 31A can be a straight line extending in a direction inclined with respect to the vertical direction (V) of the elastic arm plate 6, or a curved line. Since the vertical weld line portion 31A in this figure extends in the vertical direction (V) which is the longitudinal direction of the elastic arm plate 6, the region extending in the vertical direction (V) of the laminated portion 40 of the elastic arm plate 6 can be tightly attached to the terminal plate 3 even in a state in which the elastic arm plate 6 is elastically deformed to be curved in the vertical direction (V). This prevents the contact position of the movable contact 7 and the fixed contact 5 from shifting, realizing the feature of stabilizing the contact pressure of the contacts.

[0063] In addition, the laser welded portion 30 can be arranged with the weld lines 31 as two or more rows of vertical weld lines 31A (FIG. 10) and / or two or more rows of horizontal weld lines 31B. The vertical weld lines 31A can be arranged at intervals in the width direction (W) of the elastic arm plate 6 (two rows in FIG. 10), and the horizontal weld lines 31B can be arranged at intervals in the longitudinal direction of the elastic arm plate 6. This prevents the contact position of the movable contact 7 and the fixed contact 5 from shifting, thereby realizing the feature of stabilizing the contact pressure of the contacts. Furthermore, the laser welded portion 30 can be arranged with the weld lines 31 as annular weld lines extending along an annular shape, and can be regular or irregular, for example, circular, elliptical, oblong, rectangular, etc.

[0064] Furthermore, by combining one or more vertical weld lines 31A with one or more horizontal weld lines 31B, it is possible to form regular or irregular shapes, such as a triangle, a roughly rectangular shape, a rectangular shape, a polygonal shape, an oval shape, a wavy shape, a concave-convex shape, a zigzag shape, or a one-stroke shape. Furthermore, any one or more of these can be combined. In any case, it is possible to realize the feature that the contact pressure of the contacts can be stabilized by preventing the contact position of the movable contact 7 and the fixed contact 5 from shifting. (Contact activation treatment)

[0065] The contact resistance of the micro breaker with weak contact pressure can be reduced by activating the contacts in the assembled state. The activation process of the contacts is performed by ultrasonically vibrating the contacts of the assembled breaker 100 while current is flowing. The breaker 100 causes the movable contact 7 and the fixed contact 5 to collide with each other and ultrasonically vibrate in the direction of separation. That is, the breaker 100 ultrasonically vibrates the fixed contact 5 and the movable contact 7 so that they approach each other, collide with each other, and move relatively in the direction of separation. The current of the contacts in the ultrasonic vibration state is preferably 0.1 A to 100 A in the resistive load state. The contacts are more effectively activated by increasing the contact current during ultrasonic vibration. In the case of an inductive load in which a coil is connected in series with a resistor, the current energy stored in the coil when the current is interrupted is large, so the contact current can be reduced to activate the contacts. This is because the discharge current of the contacts is large to consume the energy of the current stored in the coil. Therefore, the contact current is set to an optimal value in consideration of the resistive load and the inductive load. Furthermore, the breaker 100 has the characteristic that when the current through the contacts is increased, it generates heat due to Joule heat and switches itself to the OFF state. To activate the contacts with ultrasonic vibration, it is necessary to hold the movable contact 7 in the ON state in contact with the fixed contact 5. Therefore, the method of passing a large current through the contacts to generate ultrasonic vibration shortens the time for which ultrasonic vibration is generated, and ultrasonic vibration is generated while the contacts are in the ON state. Therefore, the method of passing a large current through the contacts to generate ultrasonic vibration shortens the time for which ultrasonic vibration is generated.

[0066] The time for which the contact is ultrasonically vibrated in a current-carrying state is set to 0.1 milliseconds to 1 second. The contact can be activated more effectively by making the ultrasonic vibration time longer, but if the time is too long, the silver plating layer of the contact will be damaged, so the time is set so that the contact can be activated without damaging the silver plating layer. In addition, the activation of the contact by ultrasonic vibration is also affected by the contact current, the type of load, and the amplitude of the ultrasonic vibration, and the contact is activated more effectively in a short time when the contact current and amplitude are large. Therefore, the time for which the ultrasonic vibration is applied is set to an optimal value within the above-mentioned range, taking into account the contact current and the amplitude of the ultrasonic vibration.

[0067] The frequency at which the contacts are ultrasonically vibrated is 20KHz to 6GHz, preferably 20KHz to 1GHz. By increasing the frequency of the ultrasonic vibration, the number of collisions and separations between the movable contact 7 and the fixed contact 5 per unit time can be increased. However, if the frequency of the ultrasonic vibration is too high, the distance between the movable contact 7 and the fixed contact 5 becomes narrow, and activation by discharge decreases, whereas if the frequency is too low, the number of collisions decreases and activation decreases. Therefore, the frequency of the ultrasonic vibration is set to an optimal value in consideration of the thickness and length of the elastic arm plate 6 and the resonant frequency of the elastic arm plate 6.

[0068] Furthermore, the amplitude of ultrasonic vibration of the breaker 100 is set to 0.01 μm to 100 μm. By increasing the amplitude of ultrasonic vibration, the kinetic energy of the collision of the movable contact 7 with the fixed contact 5 can be increased, and the distance at which the movable contact 7 is separated from the fixed contact 5 can be increased. The amplitude of ultrasonic vibration of the breaker 100 affects the distance at which the movable contact 7 is separated from the fixed contact 5. However, the distance at which the movable contact 7 is separated from the fixed contact 5 can be made larger than the amplitude of ultrasonic vibration of the breaker 100 by resonating the elastic arm plate 6. Therefore, by setting the frequency at which the ultrasonic vibration of the breaker 100 is performed to the resonant frequency of the elastic arm plate 6 or in the vicinity thereof, or to an integer multiple of the resonant frequency, or to an integer fraction of the resonant frequency, the movable contact 7 can be separated from the fixed contact 5 by a sufficient distance, and can be effectively activated.

[0069] In order to increase the amplitude of ultrasonic vibration of the breaker 100, it is necessary to increase the output of the ultrasonic vibrator or ultrasonic horn that contacts and ultrasonically vibrates the breaker 100. If a high-output ultrasonic vibrator or ultrasonic horn is pressed against the case 1 of the breaker 100 to cause ultrasonic vibration, there are problems such as deformation of the contact point with the ultrasonic vibrator due to heat generated by the ultrasonic vibration, so the amplitude of ultrasonic vibration of the breaker 100 is set small within a range that still activates the contact points. (Heater 9)

[0070] The heater 9 generates heat when energized, and heats the bimetal 8. The heater 9 is a thick PTC heater with oval or rectangular opposing surfaces, and has electrodes on the top and bottom surfaces. However, it is not necessary to use a PTC heater, and any heater that can heat the bimetal 8 when energized can be used. The heater 9, which has electrodes on the top and bottom surfaces, is designed so that its bottom surface contacts the fixed contact metal plate 4 and its top surface contacts the elastic arm plate 6 via the bimetal 8. In the ON state where the movable contact 7 of the elastic arm plate 6 contacts the fixed contact 5, the elastic arm plate 6 and the bimetal 8 are not in contact with each other, and no current is passed through the heater 9. In the OFF state where the movable contact 7 of the elastic arm plate 6 is separated from the fixed contact 5, the heater 9 is energized through the bimetal 8 in contact with the elastic arm plate 6 and the fixed contact metal plate 4, generating heat and heating the bimetal 8. The heated bimetal 8 maintains the OFF state where the movable contact 7 is separated from the fixed contact 5. This non-energized type breaker 100 maintains the movable contact 7 in the OFF state when switched to the OFF state, so it can be used safely with battery packs. This is because, after the battery pack is used in an abnormal state and the temperature rises above the set temperature and the non-energized type breaker 100 is switched to the OFF state, electricity continues to flow from the battery of the battery pack to the heater 9, heating the bimetal 8, so that the breaker 100 does not return to the ON state and can maintain the current interrupting state until the battery is discharged.

[0071] However, the breaker is not necessarily limited to a structure having a heater built in. In a breaker without a heater built in, when the bimetal 8 becomes warmer than the set temperature and deforms, deforming the elastic arm plate 6 to switch the contact to the OFF state, the bimetal 8 is not heated to hold the breaker in the OFF state, but when the bimetal 8 drops to a specified temperature, the bimetal 8 and the elastic arm plate 6 are restored to their original state and the breaker is switched to the ON state. (Bimetal 8)

[0072] The bimetal 8 is a laminate of metals with different thermal expansion coefficients so that it deforms when heated. The bimetal 8 is disposed between the heater 9 and the elastic arm plate 6, and when heated, it deforms so as to reverse, and the movable contact 7 is separated from the fixed contact 5 to switch the breaker 100 to the OFF state. The bimetal 8 has a shape that is curved with a central convexity, and when it is not thermally deformed, that is, when the movable contact 7 is in contact with the fixed contact 5, it is in a position in which the central protrusion protrudes toward the elastic arm plate 6 as shown in FIG. 6, and when it is thermally deformed so as to reverse, it is in a position in which the central protrusion protrudes toward the heater 9. When the bimetal 8 is thermally deformed and reversed, it brings the central protrusion into contact with the heater 9 and presses both ends against the elastic arm plate 6, pushing up the movable part 6A of the elastic arm plate 6 to separate the movable contact 7 from the fixed contact 5 to switch the breaker 100 to the OFF state.

[0073] As shown in Fig. 6, the breaker 100 is fixed to the circuit board by soldering the connection terminal 3X of the terminal board 3 and the connection terminal 4X of the fixed contact metal plate 4, which are drawn out from both ends of the case 1. The breaker 100 is placed on the circuit board and soldered with the bottom surface of the case 1, i.e., the bottom surface of the main body case 1A, facing the upper surface of the circuit board. The breaker 100 is heated and reflow soldered in a state where the connection terminals 3X and 4X provided on both ends of the case 1 are arranged on a solder surface provided on the surface of the circuit board. The breaker 100 is connected to the solder surface of the circuit board via the connection terminals 3X and 4X, and is fixed in a fixed position on the circuit board.

[0074] Furthermore, the breaker 100 can be fixed by soldering the connection terminal 3X of the terminal board 3 drawn out from one end of the case 1 to the outside and the exposed terminal 44 of the fixed contact metal plate 4 exposed from the surface on the bottom side of the main case 1A to the circuit board. Since the exposed terminal 44 of the fixed contact metal plate 4 of the breaker 100 is connected to the circuit board, the connection terminal 4X can be shortened. The breaker 100 is also arranged and soldered on the top surface of the circuit board with the bottom surface of the case 1, i.e., the bottom surface of the main case 1A, facing the top surface of the circuit board. The breaker 100 is heated and reflow soldered in a state where the connection terminal 3X provided at one end of the case 1 and the exposed terminal 44 exposed from the surface on the bottom side of the main case 1A are arranged on the solder surface provided on the surface of the circuit board. The breaker 100 is connected to the solder surface of the circuit board via the connection terminal 3X and the exposed terminal 44 and fixed in a fixed position on the circuit board. (Embodiment 2)

[0075] In the above-mentioned breaker 100, a pair of connection terminals 4X connected to the fixed contact metal plate 4 and a pair of connection terminals 3X connected to the terminal plate 3 connected to the elastic arm plate 6 are arranged at the corners 1D of each end 1C of the bottom surface of the case 1, i.e., toward both ends in the width direction (W) of the case 1. However, as shown in the breaker 200 of FIG. 13, the connection terminals 3X and 4X can be arranged as one connection terminal each at each end 1C of the bottom surface of the case 1. By making the connection terminals 3X and 4X into one connection terminal each, a larger contact area can be secured than with a pair of connection terminals. In the breaker 200, one connection terminal 4X and 3X are arranged at each end 1C of the bottom surface of the case 1, one connection terminal 4X is connected to the fixed contact metal plate 4, and the other connection terminal 3X is provided on the terminal plate 3 connected to the elastic arm plate 6. As shown in Figs. 14 to 17, the breaker 200 has a connection terminal 3X connected to the elastic arm plate 6 with the width of the lower welding plate 3A as one connection terminal, and a connection terminal 4X connected to the fixed contact metal plate 4 as one connection terminal. The terminal plate 3 of the breaker 200 has a lower welding plate 3A to which the upper welding plate 6B is welded and fixed, a rising portion 3B connected to the side edge of the lower welding plate 3A, and one connection terminal 3X connected to the lower end of the rising portion 3B. In the terminal plate 3 of Fig. 14, the lower welding plate 3A, the rising portion 3B, and one connection terminal 3X all extend in the width direction (W) of the case 1 and each has the same width, but any one or each can have a different width. The above breaker 200 is similar to the breaker 100 except that the connection terminals 3X and 4X are each one connection terminal, and the above description of the breaker 100 is applicable. [Industrial Applicability]

[0076] The present invention can be suitably used as a breaker that is optimal for SMD (surface mount device) by reducing the external size while reliably connecting the elastic arm plate and the terminal plate and arranging them in fixed positions in the case. can be achieved. [Explanation of symbols]

[0077] 100, 200, 800, 900...Breaker 1. Case 1A…Main unit case 1B…Lid case 1C...End 1D…Corner 3...Terminal board 3a…Exposed part 3A…Lower welding plate 3B…Rising part 3X…Connection terminal 4…Fixed contact metal plate 4X…Connection terminal 4A…Tip 4B: Middle section 4C…Rear end 4D…Step part 5…Fixed contact 6...Elastic arm plate 6A…Movable parts 6B…Upper welding plate 6C…Protrusion 6D...Tip 6E…Rear end 7…Movable contact 8…Bimetal 9. Heater 10...Outer wall 11…Exterior wall 11A…First exterior wall 11B…Second outer wall 12...Facing wall 13...Bottom 15…Bottom plate 15A…Opening 16…Fitting protrusion 17…Connecting protrusion 18...Connecting recess 19...Protruding part 20…Storage space 21…Recess 22...Outer wall 23…Storage section 24…Step recess 25…Pressing protrusion 26…Deformation limiting convex part 29…Storage recess 30…Laser welded part 31…Welding line 31A: Vertical weld line 31B…Horizontal welding line section 32…Welding spot 40…Laminated section 44...Exposed terminal 51...Pusher 52…Base plate 53…Support rib 803...Terminal board 901...Plastic 903...Terminal board 906…Elastic arm plate

Claims

1. A breaker having all of the following configurations (a) to (i). (a) The breaker has a fixed contact metal plate having a fixed contact; an elastic arm plate having a movable contact at a tip end thereof, the movable contact being disposed at a position opposite the fixed contact; a terminal plate to which an upper welding plate provided at a rear end of the elastic arm plate is fixed via a laser welding portion; a plastic case in which the terminal plate and the fixed contact metal plate are fixed; and a bimetal that presses the elastic arm plate to switch the movable contact from on to off. (b) the case is made of plastic; The elastic arm plate is disposed inside a hollow storage space. (c) the case, a connection terminal electrically connected to the fixed contact metal plate; A connection terminal electrically connected to the elastic arm plate is disposed at each end of the bottom surface. (d) the terminal board, The upper welding plate of the elastic arm plate exposed in the storage space of the case is welded in a stacked state to a lower welding plate. (e) the terminal board, The side edge of the lower welding plate extending in the width direction of the case, The connection terminals are connected via the rising portions. (f) the terminal board, The connection terminal is connected to the lower welding plate via the rising portion, It is disposed at the end of the bottom surface of the case. (g) the rising portion is Through the case, The housing is embedded in the plastic of the case in a plane parallel to the width direction of the case, The lower welding plate is placed in the storage space, The connection terminal is disposed on the bottom surface of the case. (h) the width (W1) of the lower welding plate is wider than the width (W2) of the upper welding plate; The upper and lower weld plates are in close contact with each other and connected by a laser welded portion. (i) the connection terminal is The insulating member is disposed on the bottom surface of the case in such a manner that it extends in the vertical direction of the case from the connecting portion with the rising portion toward the tip.

2. We have added a specific example of a pair of connection terminals as a subclaim.

2. The breaker of claim 1, The terminal board is A pair of the connection terminals are disposed apart from each other, The pair of connection terminals are disposed at the corners of the bottom surface of the case.

3. 2. The breaker of claim 1, A breaker in which the laser welded portion is one or more linearly extending weld lines.

4. 2. The breaker of claim 1, The breaker, wherein the laser weld is one or more weld spots.

5. 2. The breaker of claim 1, The thickness of the elastic arm plate is 50 μm or more and 200 μm or less. A breaker characterized in that it is a micro breaker.

6. 2. The breaker of claim 1, The case is The fixed contact metal plate and the terminal plate are embedded in an outer peripheral wall, The inside of the outer peripheral wall is used as a storage space for arranging the elastic arm plate, An exposed portion is provided in the storage space by exposing the lower welding plate of the terminal board, The terminal board is The breaker is formed by laminating the upper weld plate of the elastic arm plate on the lower weld plate and laser welding them.

7. A breaker according to any one of claims 1 to 6, The fixed contact and the movable contact are A breaker having activated contacts that have been activated by ultrasonic vibration in a conducting state.

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