Circuit breaker

Abstract

To provide a circuit breaker that can improve ease of assembly and productivity by using a holder unit equipped with a connection plate that can be used with all mechanical or electronic wiring circuit breakers and earth leakage circuit breakers.SOLUTION: A holder unit 12 supporting a movable contact 11 includes a contact support portion 21 fixed to the bottom 2a of a main body case 2 and supporting the base end part 11b of the movable contact so as to be freely rotatable, and a connection plate 20 connected to an overcurrent protection device with a connecting screw. The connection plate includes a first through hole 26a facing a first screw hole 14a formed in a first connection component 14 of a mechanical overcurrent protection device 6, and a second through hole 26b facing the second screw hole 43a formed in a second connection component 43 of an electronic overcurrent protection device 41.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a circuit breaker for low-voltage power distribution systems, used as a molded case circuit breaker or an earth leakage circuit breaker. [Background technology]

[0002] A molded case circuit breaker is used as a circuit breaker for a low-voltage power distribution system. The molded case circuit breaker includes a main circuit contactor consisting of a fixed contactor and a movable contactor, a holder unit that rotatably supports the movable contactor, an opening / closing mechanism that opens and closes the movable contactor, and an overcurrent protection device. The holder unit includes a connection plate that is connected to the movable contactor and extends to the load side. A screw through hole is formed in the load side end of the connection plate. The overcurrent protection device mounted on the load side is provided with a connection part having a screw hole. The connection plate and the connection part are overlapped so that the screw through hole and the screw hole face each other, and a connecting screw that has passed through the screw through hole from the connection plate is screwed into the screw hole of the connection part, thereby connecting the connection plate of the holder unit and the connection part of the overcurrent protection device.

[0003] Here, there are mechanical type circuit breakers and electronic type circuit breakers (for example, Patent Document 1). A plate-shaped heater for heating the bimetal of the thermal trip device is connected to a connection plate provided on the holder unit of the mechanical type circuit breaker with a connecting screw. Also, a connection conductor of a current transformer that converts the current flowing through the main circuit into a current signal is connected to a connection plate provided on the holder unit of the electronic type circuit breaker. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 4-123740 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, the positions of the screw hole of the heater and the screw hole of the connecting conductor of the current transformer are different from each other. Therefore, the connection plate of one type of holder unit cannot be used as a common part for both the mechanical type molded circuit breaker and the electronic type molded circuit breaker. Therefore, a holder unit with a dedicated connection plate is required for each of the mechanical type molded circuit breaker and the electronic type molded circuit breaker, which increases the number of parts and deteriorates the ease of assembly and productivity of the circuit breaker.

[0006] In addition, there are mechanical and electronic earth leakage circuit breakers used as circuit breakers in low-voltage distribution systems, and each of them requires a holder unit with a dedicated connection plate, so they have similar issues.

[0007] Therefore, the present invention aims to provide a circuit breaker that can be easily assembled and manufactured by using a holder unit equipped with a connection plate that is compatible with all mechanical or electronic molded-case circuit breakers and mechanical or electronic earth leakage circuit breakers. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one embodiment of the circuit breaker of the present invention is a circuit breaker having a main body case inside which are mounted a fixed contactor having a fixed contact, a movable contactor in which a movable contact is brought into and out of engagement with the fixed contactor, a holder unit supporting the movable contactor, an opening / closing mechanism for opening and closing the movable contactor, and an overcurrent protection device connected to the load side of the holder unit, wherein the holder unit is provided with a contactor support part fixed to the bottom of the main body case and supporting the base end of the movable contactor so as to be freely rotatable, and a connection plate connected to the overcurrent protection device by a connecting screw, and the connection plate is formed with a first through hole opposite a first screw hole formed in a first connecting part of the mechanical overcurrent protection device, and a second through hole opposite a second screw hole formed in a second connecting part of the electronic overcurrent protection device. Effect of the Invention

[0009] According to the circuit breaker of the present invention, by using a holder unit equipped with a connection plate that can be used with both mechanical or electronic molded-case circuit breakers and mechanical or electronic earth leakage circuit breakers, it is possible to improve ease of assembly and productivity. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a mechanical molded circuit breaker according to the present invention with a portion of a main body case removed; [Diagram 2] FIG. 2 is a perspective view showing a holder unit constituting the mechanical molded case circuit breaker. [Diagram 3] FIG. 2 is a perspective view showing a holder base portion constituting the holder unit. [Figure 4] FIG. [Diagram 5] 5 is a view showing the holder unit with the holder case of FIG. 4 attached thereto, viewed from the connection plate side. [Figure 6] 13 is a diagram showing a state in which a contact supporting portion of the holder unit is held by an engaging and holding piece provided on the lower case. FIG. [Figure 7] 1 is a perspective view showing an electronic molded circuit breaker according to the present invention with a portion of a main body case removed; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Next, an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are given the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between thickness and planar dimensions, the thickness ratio of each layer, etc., differ from the actual ones. Therefore, the specific thickness and dimensions should be determined with reference to the following description. In addition, it goes without saying that the drawings include parts with different dimensional relationships and ratios.

[0012] In addition, the embodiments shown below are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, arrangements, etc. of the components to those described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0013] FIG. 1 is a cross-sectional view showing a first embodiment of a mechanical circuit breaker 1 for three-phase (R, S, T phase) AC connected between the power supply side and the load side of a circuit, and shows the circuit structure of one of the phases assembled in parallel in a main body case 2.

[0014] The mechanical circuit breaker 1 has, inside a main body case 2, a switching mechanism 4 that opens and closes the switching contacts 3, a switching handle 5 that operates the switching mechanism 4, an overcurrent trip device 6 that causes the switching mechanism 4 to trip when an overcurrent flows in the main circuit, and an arc extinguishing device 7.

[0015] The main body case 2 is constructed by assembling a power supply side intermediate case 2b and a load side intermediate case 2c on top of a lower case 2a, and assembling a top cover 2d on top of the power supply side intermediate case 2b and the load side intermediate case 2c. A power supply side main circuit terminal 8 and a load side main circuit terminal 9 are fixed to the lower case 2a. The switching contacts 3 are constructed of a fixed contactor 10 having a fixed contact 10a and a movable contactor 11 having a movable contact 11a, and the movable contactor 11 is rotatably supported by a holder unit 12. The fixed contactor 10 is connected to the power supply side main circuit terminal 8, and the movable contactor 11 is connected to the load side main circuit terminal 9 via the holder unit 12 and the overcurrent trip device 6.

[0016] The opening / closing mechanism 4 is composed of a toggle link mechanism (not shown) that links the movable contact 11 and the opening / closing handle 5, a latch mechanism that combines a latch (not shown) and a trip crossbar 13. When the trip crossbar 13 rotates counterclockwise, the opening / closing mechanism 4 trips, causing the movable contact 11 to perform an opening operation.

[0017] The overcurrent tripping device 6 is equipped with a heater 14 that heats up when an overcurrent flows between the power supply side main circuit terminal 8 and the load side main circuit terminal 9, a bimetal 15 to which the lower part of the heater 14 is fixed, and an adjustment screw 16 that engages with the upper free end of the bimetal 15 and can be moved back and forth to provide a specified gap between the trip crossbar 13.

[0018] 2 to 5 show the structure of the holder unit 12 that rotatably supports the movable contact.

[0019] As shown in FIG. 2, the holder unit 12 includes a holder base 22 having a connection plate 20 and a contact support portion 21, a pivot shaft 23 attached to the contact support portion 21 to support the movable contact 11 so as to be freely rotatable, a contact spring 24 and a compression spring 25, and a holder case 31 shown in FIG. 4.

[0020] 3, in the holder base 22, the contact support portion 21 is formed continuously with one end side in the longitudinal direction of the rectangular connecting plate 20. A potbellied through hole 26 is formed in the other end side in the longitudinal direction of the connecting plate 20. The potbellied through hole 26 is formed by a first through hole 26a and a second through hole 26b of the same diameter penetrating the connecting plate 20 while overlapping with their centers shifted from each other in the longitudinal direction.

[0021] The contact support portion 21 is formed continuously from the other longitudinal end side of the connecting plate 20 and comprises a rectangular bottom plate 27 having a screw hole 27a formed therein, a pair of connecting plates 28a, 28b formed continuously from both sides of the width of the bottom plate 27 and extending overlapping the upper surface of the bottom plate 27, and a pair of support plates 29a, 29b rising parallel to each other from the edges of the pair of connecting plates 28a, 28b, and an axial hole 30 is formed in the pair of support plates 29a, 29b.

[0022] As shown in Fig. 2, the base end 11b of the movable contact 11 is inserted between a pair of support plates 29a, 29b of the contact support part 21, and the rotating shaft 23 is inserted into an axial hole 11c (see Fig. 1) formed in the base end 11b and an axial hole 30 of the pair of support plates 29a, 29b, so that the movable contact 11 is rotatably supported by the contact support part 21. As shown in Fig. 2, the contact spring 24 has a pair of coil parts 24a, 24b arranged so as to surround the rotating shaft 23 outside the pair of support plates 29a, 29b, and an engagement part 24c that connects between the pair of coil parts 24a, 24b and engages with the upper part of the movable contact 11. A pair of compression springs 25 are arranged outside the pair of support plates 29a, 29b so as to surround the rotating shaft 23 inside the coil parts 24a, 24b of the contact spring (see Fig. 5).

[0023] As shown in Fig. 4, the holder case 31 is attached in a state of covering the contact support part 21 of the holder base part 22, the contact spring 24, and the pair of compression springs 25. Fig. 5 shows the inside of the holder case 31 from the connection plate 20 side, and the contact spring 24 exerts a spring restoring force on the open movable contact 11 in a closing direction (counterclockwise in Fig. 4) by engaging its ends 24a1, 24b1 with the holder case 31. The pair of compression springs 25, 25 are arranged in a compressed spring state inside the holder case 31, and exert a spring force in a direction in which the pair of support plates 29a, 29b come into close contact with the base end part 11b of the movable contact 11 in a surface contact state. As a result, as shown in Fig. 5, the parts where the base end part 11b of the movable contact 11 and the pair of support plates 29a, 29b come into close contact with each other in a surface contact state are sliding current-carrying parts 32a, 32b.

[0024] 1, the holder unit 12 having the above configuration is fixed by threading a case fixing screw 33, which passes through a through hole of the lower case 2a from below, into a screw hole 27a formed in the bottom plate 27 of the contact support part 21. The connection plate 20 of the holder unit 12 is connected to the heater 14 of the overcurrent tripping device 6 with a connecting screw 35. At this time, the screw hole 14a formed in the heater 14 faces the first through hole 26a of the connection plate 20, and the connecting screw 35 passes through the first through hole 26a from below and is screwed into the screw hole 14a of the heater 14, whereby the connection plate 20 and the heater 14 are connected.

[0025] The mechanical overcurrent protection device according to the present invention corresponds to the overcurrent tripping device 6. The bottom of the main body case according to the present invention corresponds to the lower case 2a. The first connection part according to the present invention corresponds to the heater 14, and the first screw hole according to the present invention corresponds to the screw hole 14a.

[0026] Here, as shown in Fig. 6, an engagement retaining piece 34 is formed on the lower case 2a, and this engagement retaining piece 34 engages from above with the connecting plate 28b of the holder base 22. In addition, although not shown in Fig. 6, an engagement retaining piece 34 that engages from above with the connecting plate 28a of the holder base 22 is formed on the lower case 2a.

[0027] In the mechanical circuit breaker 1 configured as described above, when an overcurrent flows between the power source side main circuit terminal 8 and the load side main circuit terminal 9, the bimetal 15 bent by the heating of the heater 14 comes into contact with the trip crossbar 13 of the switching mechanism 4, causing the trip crossbar 13 to rotate counterclockwise, and the movable contact 11 performs a current-limiting opening operation as the switching mechanism 4 trips.

[0028] The movable contact 11 performing the current-limiting opening operation stops when it abuts against the inner wall 2b1, which serves as a stopper provided on the power supply side intermediate case 2b shown in FIG. 1. Due to the reaction force generated when the movable contact 11 abuts against the inner wall 2b1, an external force acts on the contact support part 21 of the holder base part 22 supporting the base end part 11b of the movable contact 11, causing it to rise up away from the lower case 2a. If an external force such as lifting acts on the contact support part 21, damage or deformation of the sliding current-carrying parts 32a, 32b may occur, which may affect the opening operation and current-carrying function of the movable contact 11. However, in this embodiment, the engagement retaining piece 34 formed on the lower case 2a engages with the connecting plates 28a, 28b of the contact support part 21 from above, thereby restricting the lifting up of the contact support part 21 caused by the movable contact 11 abutting against the inner wall 2b1. This prevents damage and deformation of the sliding parts of the sliding current-carrying parts 32a and 32b, so that the contact-opening operation and current-carrying function of the movable contact 11 are not affected.

[0029] Next, the circuit breaker shown in FIG. 7 is a cross-sectional view showing an electronic molded circuit breaker 40 for three-phase (R, S, T phases) AC connected between the power supply side and the load side of the main circuit, and shows the circuit structure of one of the phases assembled in parallel in the main case 2.

[0030] The electronic circuit breaker 40 of this embodiment is equipped with a main body case 2, switching contacts 3, switching mechanism 4, switching handle 5, arc extinguishing device 7 and holder unit 12, which are configured identically to the mechanical circuit breaker 1 shown in Figures 1 to 6, as well as a current detection device 41 that detects the current in the main circuit, and a trip coil unit 42.

[0031] The trip coil unit 42 is equipped with a printed circuit board that implements circuit components of an overcurrent detection circuit that detects the occurrence of an overcurrent from the output level of the current detection device 41, and when an overcurrent is detected, it rotates the trip crossbar 13 counterclockwise to initiate the trip operation of the opening and closing mechanism 4.

[0032] The current detection device 41 is formed with a connection conductor 43 that is connected to the connection plate 20 of the holder unit 12, and a screw hole 43a is formed in the connection conductor 43. When the current detection device 41 is assembled into the lower case 2a, the screw hole 43a formed in the connection conductor 43 faces the second through hole 26b of the connection plate 20. As a result, the connection plate 20 of the holder unit 12 and the current detection device 41 are connected by passing the connecting screw 35 through the second through hole 26b from below and screwing it into the screw hole 43a of the connection conductor 43.

[0033] An electronic overcurrent protection device according to the present invention corresponds to current detection device 41. A second connecting component according to the present invention corresponds to connecting conductor 43, and a second screw hole according to the present invention corresponds to screw hole 43a.

[0034] In the electronic wiring circuit breaker 40 configured as described above, when an overcurrent flows between the power source side main circuit terminal 8 and the load side main circuit terminal 9, the current detection device 41 detects the occurrence of the overcurrent, causing the trip coil unit 42 to rotate the trip crossbar 13 of the opening / closing mechanism 4 counterclockwise, and the movable contact 11 performs a current-limiting opening operation.

[0035] Here, this embodiment is also composed of a main body case 2 and a holder unit 12 having the same shape as the mechanical molded case 1 shown in Fig. 1 to Fig. 6, and an engagement retaining piece 34 formed on the lower case 2a engages from above with the connecting plates 28a, 28b of the contact support part 21. As a result, even if the movable contact 11 performing the current-limiting opening operation abuts against the inner wall 2b1 of the power supply side intermediate case 2b, the engagement retaining piece 34 of the lower case 2a restricts the contact support part 21 of the holder base 22 from floating up, so that damage and deformation of the sliding parts of the sliding current-carrying parts 32a, 32b are prevented, and the opening operation and current-carrying function of the movable contact 11 are not affected.

[0036] Therefore, the connection plate 20 of the holder unit 12 is formed with a first through hole 26a to which the heater 14 of the overcurrent tripping device 6 of the mechanical molded circuit breaker 1 can be connected with a connecting screw 35, and a second through hole 26b to which the connection conductor 43 of the electronic molded circuit breaker 40 can be connected with a connecting screw 35, and the holder unit 12 can be used as a common part for the mechanical molded circuit breaker 1 and the electronic molded circuit breaker 40. Therefore, by using the holder unit 12, the number of parts required when manufacturing the mechanical molded circuit breaker 1 and the electronic molded circuit breaker 40 can be reduced, and ease of assembly and productivity can be improved.

[0037] In addition, the engagement retaining pieces 34 formed on the lower case 2a engage with the contact support parts 21 (connecting plates 28a, 28b) of the holder unit 12 from above, and restrict the contact support parts 21 from floating up when the movable contact 11 performing the current-limiting opening operation abuts against the inner wall 2b1 of the power supply side intermediate case 2b. This prevents damage and deformation of the sliding parts of the sliding current-carrying parts 32a, 32b of the holder unit 12, and does not affect the opening operation and current-carrying function of the movable contact 11.

[0038] Although the present embodiment has been described with respect to the mechanical molded-case circuit breaker 1 and the electronic molded-case circuit breaker 40, the connection plate 20 of the holder unit 12 can also be applied when connecting to a heater of an overcurrent tripping device of a mechanical earth leakage circuit breaker or a connection conductor of a current detection device of an electronic earth leakage circuit breaker. Therefore, the number of parts required for manufacturing the mechanical earth leakage circuit breaker and the electronic earth leakage circuit breaker is reduced, and the ease of assembly and productivity of the mechanical earth leakage circuit breaker and the electronic earth leakage circuit breaker can be improved. [Explanation of symbols]

[0039] 1 Mechanical wiring circuit breaker 2 Main unit case 2a Lower Case 2b Power supply intermediate case 2b1 Inner wall 2c Load side intermediate case 2d Top cover 3 Switching Contacts 4 Opening and closing mechanism 5 Opening and closing handle 6. Overcurrent tripping device 7 Arc extinguishing device 8 Power supply side main circuit terminal 9 Load side main circuit terminal 10 Fixed contact 10a fixed contact 11 Movable contact 11a Movable contact 11b Proximal end 12 Holder unit 13 Trip Crossbar 14 Heater 14a Heater screw hole 15 Bimetal 16 Adjustment screw 20 Connection plate 21 Contact support part 22 Holder base 23 Rotating shaft 24 Contact Spring 24a, 24b Coil section 24c Engagement part 25 compression spring 26 Daruma-shaped through hole 26a 1st through hole 26b Second through hole 27 Bottom plate 27a screw hole 28a,28b connecting plate 29a,29b Support plate 30 Shaft hole 31 Holder case 32a, 32b Sliding current-carrying part 33 Case fixing screw 34 Engagement holding piece 35 Connecting screw 40 Electronic circuit breaker 41 Current detection device 42 Trip coil unit 43 Connecting conductor 43a screw hole

Claims

1. A circuit breaker including a main body case, a fixed contactor having a fixed contact, a movable contactor having a movable contact that moves with and away from the fixed contactor, a holder unit supporting the movable contactor, a switching mechanism for switching the movable contactor, and an overcurrent protection device connected to a load side of the holder unit, the holder unit includes a contact support portion fixed to a bottom portion of the main body case and rotatably supporting a base end portion of the movable contact, and a connection plate connected to the overcurrent protection device by a connecting screw; a first through hole formed in the connecting plate facing a first screw hole formed in a first connecting part of the mechanical overcurrent protection device, and a second through hole formed in a second screw hole formed in a second connecting part of the electronic overcurrent protection device.

2. The circuit breaker according to claim 1, characterized in that the first through hole and the second through hole are formed into a daruma shape by overlapping and penetrating with their centers offset from each other in the longitudinal direction of the connection plate extending toward the load side.

3. 3. The circuit breaker according to claim 1, further comprising a lift-up prevention means for preventing the contact support portion from lifting up due to a reaction force from the movable contact when the movable contact performing an opening operation abuts against a stopper of the main body case.

4. The circuit breaker according to claim 3, characterized in that the lift-up prevention means is an engaging and retaining piece that rises from the bottom of the main body case, engages with the upper surface of the contact support portion, whose lower surface is placed on the bottom of the main body case, and prevents the contact support portion from moving away from the bottom.

Images