JP4753263B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker such as a circuit breaker for wiring or an earth leakage breaker.

  Circuit breakers such as circuit breakers and earth leakage circuit breakers open the circuit when an abnormal current flows in the circuit such as the load or circuit on the secondary side due to an overload or short circuit. It is an apparatus used to avoid load circuits and electric wires from being damaged by cutting off the power supply from the power supply. In such circuit breakers, such as circuit breakers for wiring and earth leakage circuit breakers, in order to open the circuit when energized with overcurrent or rated current, the movable contact provided on the movable contactor that is normally in contact is fixed. The fixed contacts provided on the contacts are separated from each other. When these contacts are separated, an arc is generated between the contacts. Since the arc is a thermal or electromagnetic force burden on the circuit breaker components, it is necessary to extinguish the arc quickly. The arc-extinguishing chamber of the circuit breaker is provided with an arc-extinguishing insulation molding to extinguish the arc. This arc-extinguishing insulation molding is exposed to the arc generated between the contacts when an overcurrent is interrupted. Then, by decomposing and gasifying the constituent material itself of the molded product, arc extinguishing gas for cooling and blowing off the arc is generated, which contributes to arc extinguishing.

Examples of the material constituting the arc-extinguishing insulating molding include, for example, Patent Document 1, an acrylate copolymer, an aliphatic hydrocarbon resin, polyvinyl alcohol, polybutadiene, polyvinyl acetate, polyvinyl acetal, isoprene resin, ethylene. -An insulating material containing 5 to 35 wt% of glass fiber with respect to a resin such as propylene rubber, ethylene-vinyl acetate copolymer or polyamide is disclosed. Further, Patent Document 2 discloses a resin mainly composed of an aliphatic ketone resin, and Patent Document 3 discloses nylon and Teflon as constituent materials for an arc-extinguishing insulating molding.
Japanese Patent Laid-Open No. Sho 63-310534 JP 2001-176372 A JP 2007-149486 A

  As the demand for increasing the capacity and space saving of low-voltage wiring facilities increases, there is a demand for further miniaturization of the external dimensions of circuit breakers such as wiring breakers and earth leakage breakers. As a problem in miniaturization of a circuit breaker, there is an increase in a thermal or electromagnetic load on a component due to an arc generated when an overcurrent is interrupted. In order to reduce the energy of the generated arc, it is necessary to improve the current-limiting interruption performance that suppresses the overcurrent at the time of interruption.

  In order to improve this current limiting interrupting performance, it is important to improve the arc cooling and arc extinguishing performance by the arc extinguishing insulation molding. However, the conventional arc extinguishing insulation molding as described above is reduced in size. Corresponding sufficient current limiting performance could not be obtained.

  The present invention has been made to solve the above problems, and when the overcurrent is interrupted, the arc can be quickly cooled, and the entire arc can be quickly introduced into the arc extinguishing device. An object of the present invention is to provide a circuit breaker having high current-limiting breaking performance.

  That is, the circuit breaker of the present invention includes a fixed contact provided with a fixed contact, a movable contact provided with a movable contact, and an opening / closing mechanism that opens and closes the fixed contact and the movable contact by operating the movable contact. And an arc extinguishing device that extinguishes an arc generated when the fixed contact and the movable contact in contact with each other are separated from each other. An arc-extinguishing insulating molding containing at least one of a polyester resin and a polysaccharide-based resin is disposed.

  The arc-extinguishing insulating molding preferably includes a polyacetal homopolymer or a polyacetal copolymer. The aliphatic polyester resin is preferably polylactic acid or a derivative thereof.

  The arc-extinguishing insulating molding preferably includes a polyamide resin, and as another aspect, preferably includes an organic fiber. In addition, the arc-extinguishing insulating molding preferably includes at least one of aluminum silicate fiber, aluminum borate whisker, and alumina whisker.

  The circuit breaker further includes a plurality of arc extinguishing plates and an arc running conductor, and the arc running conductor includes a mode for transferring the generated arc to the arc extinguishing plate.

  In the present invention, a molded product containing at least one of an aliphatic polyester resin and a resin made from a polysaccharide is used as the arc-extinguishing insulating molded product. Therefore, the cooling effect on the arc by the gas generated by arc exposure of the molded product. By increasing the arc and extending the arc to increase the arc resistance, the overcurrent at the time of interrupting a large current can be suppressed to a low level. As a result, a circuit breaker having excellent breaking performance can be obtained.

  A first circuit breaker according to the present invention includes a fixed contact provided with a fixed contact, a movable contact provided with a movable contact, an opening / closing mechanism for operating the movable contact, and the fixed contact and the movable contact being separated. In a circuit breaker having an arc extinguishing device that extinguishes an arc that is sometimes generated, an arc extinguishing insulating molding made of an aliphatic polyester resin and / or a resin made from a polysaccharide is provided in the vicinity of the contact, thereby The gas generated by the exposure can suppress an overcurrent when a large current is interrupted, and a circuit breaker having an excellent interrupting performance can be obtained. In addition, in circuit breakers equipped with running conductors that move to arc extinguishing plates stacked in multiple stages, the current limiting performance is enhanced by the contribution of decomposed gas due to arc exposure of the molded resin, and the arc generated between the contacts runs. The arc running when running on the conductor was promoted, and the current limiting performance was improved. As a result, the energy injected into the circuit breaker itself at the time of overcurrent interruption is reduced, the burden on the structure of the circuit breaker is reduced, and the circuit breaker can be miniaturized.

  Hereinafter, the present invention will be described in more detail. In the following description of the embodiments, the description is made with reference to the drawings. In the drawings of the present application, the same reference numerals denote the same or corresponding parts.

An embodiment of a circuit breaker according to the present invention will be described with reference to FIGS.
FIG. 1 is a side sectional view in the vicinity of a contact of an arc extinguishing device in a circuit breaker according to the present invention, and schematically shows an off state of a circuit. As shown in FIG. 1, a movable contact 11 provided with a movable contact 12, a fixed contact 13 provided with a fixed contact 14, a movable contact 12 and a fixed contact are provided at and near the arc extinguishing device contact. An arc-extinguishing insulation molding 15 for extinguishing the arc is provided so as to surround the periphery of the arc. In FIG. 1, a part of the arc extinguishing insulation molding 15 is shown for convenience, but in actuality, a plate-like member is disposed oppositely through a contactor, or the contactor is surrounded by a U-shaped member. Arrange as follows.

  The movable contact 12 is provided on the movable side of the movable contact 11 (the side facing the fixed contact), and the fixed contact 14 is one end of the fixed contact 13 so as to contact the movable contact 12 when the circuit is on. And provided at a position facing the movable contact 12 at the time of contact. These contacts form a contact pair. In FIG. 1, the arc extinguishing insulation molding 15 is disposed in a portion exposed to an arc generated between the movable contact 12 and the fixed contact 14. This arc-extinguishing insulation molding 15 is made of a material containing at least one of an aliphatic polyester resin and a resin made from a polysaccharide.

  Next, the operation of the circuit breaker will be described. In FIG. 1, when an opening / closing mechanism (not shown) is operated, the movable contact 11 rotates and the movable contact 12 and the fixed contact 14 come into contact with or are separated from each other. Electric power is supplied from the power source to the load by bringing the contacts into contact with each other. In this state (on state), the movable contact 12 is pressed against and contacts the fixed contact 14 with a specified contact pressure in order to ensure the reliability of energization. When a short circuit accident or the like occurs and a large overcurrent flows in the circuit, the electromagnetic repulsive force on the contact surface between the movable contact 12 and the fixed contact 14 becomes very strong, and overcomes the contact pressure applied to the movable contact 12 to move the movable contact. Prior to the operation of the device (not shown) for removing the child 11 and the operation of the opening / closing mechanism, the movable contact 11 is rotated by the electromagnetic repulsive force, and the movable contact 12 and the fixed contact 14 are separated. As the separation distance from the fixed contact 14 to the movable contact 12 increases, the arc resistance increases and the arc voltage increases.

  During the breaking operation of the electric circuit by such separation, a large amount of energy (arc) is generated between the movable contact 12 and the fixed contact 14 in a short time, that is, within several milliseconds. At this time, the arc-extinguishing insulation molding 15 provided on the side of the arc extinguishing device is exposed to the arc, thereby generating a decomposition gas of the arc-extinguishing insulation molding 15 and the arc is cooled by the generated decomposition gas. Arc extinguished.

  FIG. 2 is a perspective view of an arc extinguishing device for a circuit breaker in which a plurality of arc extinguishing plates 20 having so-called U-shaped and V-shaped cutout portions 21 are stacked at a constant interval. The arc extinguishing plate 20 is made of metal, and the arc 23 generated between the movable contact 22 and the fixed contact 24 is attracted and extended by the magnetic force in the direction of the arc extinguishing plate 20, so that the arc voltage rises. Further, by taking an arc into the plurality of metal arc extinguishing plates 20, the overcurrent is limited, and the arc is extinguished to complete the interruption. Any known arc extinguishing plate 20 can be applied.

  FIG. 3 is a side sectional view of the arc extinguishing chamber of the circuit breaker. As shown in FIG. 3, the arc extinguishing chamber includes a fixed side running conductor 33 integrated with a fixed contact provided with a fixed contact 34, a movable contact 31 provided with a movable contact 32, and a plurality of arc extinguishing plates 36. The arc extinguishing device 37 is composed of a movable traveling conductor 38 and an exhaust port 39.

  A plurality of arc extinguishing plates 36 are arranged in a stacked manner as shown in FIG. 3, and are arranged between the fixed contact 34 and the movable contact 32 when the movable contact 31 taken in the arc extinguishing device 37 is separated. The generated arc (A1 in the figure) is divided. The exhaust port 39 discharges the decomposition gas of the arc-extinguishing insulation molding 35 accompanying the generation of the arc that commutates the arc on the movable contact 31 and induces it to the arc extinguishing device 37 to the outside of the circuit breaker. Is provided.

  The fixed traveling conductor 33 integrated with the fixed contact to which the fixed contact 34 is fixed extends to the arc extinguishing device 37 side. A movable contact 32 is fixed to the movable contact 31, and the movable contact 31 is connected to a movable side running conductor 38 by a conductor (not shown) and is electrically connected. These running conductors are provided for transferring the generated arc to the arc extinguishing device 37 region having arc extinguishing plates 36 stacked in multiple stages. By providing the traveling conductor in this manner, the current limiting performance can be enhanced by the contribution of the decomposition gas of the arc-extinguishing insulation molding 35 installed in the vicinity of the contact generated by the arc. Moreover, the arc transfer when the arc generated between the contacts moves (runs) the traveling conductor can be promoted, and the current limiting performance can be improved. As a result, the energy injected into the circuit breaker itself at the time of overcurrent interruption such as the occurrence of an accident is reduced, so the burden on the structure of the circuit breaker of the present invention is reduced and the circuit breaker can be downsized. It becomes. In addition, according to the present invention, it is possible to provide a circuit breaker that can cool the arc even when a large current is interrupted, and can quickly introduce the entire arc into the arc extinguishing device, and has high interrupting performance.

  In general, the fixed contact 34 or the movable contact 32 is individually provided as shown in FIG. 3. However, the fixed contact 34 or the movable contact 32 is substituted by a conductive member constituting the fixed side running conductor 33 or the movable contact 31, respectively. And may be integrated. The fixed traveling conductor 33 and the movable traveling conductor 38 to which the fixed contact 32 is fixed extend to the arc extinguishing device 37 side, and the arc extinguishing device 37 is sandwiched from both sides. Although not shown in the drawings, the arc-extinguishing chamber usually has a relay unit for detecting an abnormal current and issuing a command (opening command) for opening the contacts, and a drive mechanism unit to which the command is transmitted And the like and stored in a container made of an insulating material.

  The arc-extinguishing insulation molding 35 is made of a material containing at least one of an aliphatic polyester resin and a resin made from a polysaccharide. In FIG. 3, the arc-extinguishing insulation molding 35 is arranged so as to sandwich a space formed between both contact points 32 and 34 and between the fixed side running conductors 33 from both side surfaces (FIG. 3 shows only one side surface). Show). If the arc-extinguishing insulation molding 35 is a plate-like member, it is arranged to face each other as shown in FIG. 3, and if it is a U-shaped member, it is arranged so as to surround the space. In addition, the shape and arrangement of the arc-extinguishing insulating molding are not limited to the above examples, and a known shape and arrangement in such an arc extinguishing apparatus may be adopted.

  The exhaust port 39 is made of an insulating member and is disposed adjacent to the arc extinguishing device 37. When an overcurrent flows through the circuit breaker, an open / close mechanism (not shown) of the movable contact 31 operates to move the movable contact 32 provided in the movable contact 31 away from the fixed contact 34, and the fixed contact 34. And an arc (A1 in the figure) is generated between the movable contact 32. With the generation of the arc A1, decomposition gas is generated from the arc-extinguishing insulation molding 35 exposed to the arc, and the pressure in the arc-extinguishing chamber increases. First, the arc A1 generated between the pair of contacts 32 and 34 is subjected to the flow of cracked gas in the direction of the exhaust port due to the pressure gradient in the arc extinguishing chamber and the electromagnetic force from the overcurrent flowing through the traveling conductor, etc. The arc end on the side of the contact travels in the direction of the arc extinguishing device 37 along the fixed-side travel conductor 33 continuously extending from the fixed contact 34. Subsequently, the other arc end commutates from the fixed contact 32 to the movable traveling conductor 38 (see A2 in the figure). This commutation causes the arc to reach the arc extinguishing plate 36 of the arc extinguishing device 37 in a substantially vertical state, and is divided by the arc extinguishing plate 36 (A3 in the figure). As a result, an electrode effect voltage is generated, the arc voltage is increased, and the current limiting performance is improved.

  The arc-extinguishing insulating molded product of the present invention includes at least one of an aliphatic polyester resin and a resin made from a polysaccharide. The effect of the present invention is exhibited as long as it contains a resin made from an aliphatic polyester resin or polysaccharide. Examples of the aliphatic polyester resin include a polyester having an ester bond in the molecule and no benzene ring, and a specific example of the aliphatic polyester resin constituting the arc-extinguishing insulating molding 35 is a formula (1). Polyglycolic acid or its derivatives exemplified in

Polycaprolactone exemplified by formula (2) or a derivative thereof,

Polylactic acid exemplified by formula (3) or a derivative thereof,

Polyethylene succinate exemplified by formula (4),

Succinates such as polybutylene succinate exemplified by formula (5), polybutylene succinate adipate, polybutylene succinate carbonate, polyethylene succinate,

A polyhydroxyalkanoic acid exemplified by formula (6),

Polymalic acid exemplified by formula (7),

Polyhydroxybutyrate exemplified by formula (8),

Polydioxanone exemplified in formula (9),

A polyhydroxyalkanoate exemplified by the formula (10),

Examples thereof include polyhydroxypropionate, polyether ester, alkylene polysuccinate, polyethylene adipate and the like.

  In the case where the arc-extinguishing insulating molding includes an aliphatic polyester resin, since the ester bond is included, decomposition of the resin and generation of gas during the arc exposure are promoted. Also, it is desirable not to include a benzene ring because decomposition gas is less likely to be generated during arc exposure. Of these, polylactic acid or a derivative thereof is preferable from the viewpoint of moldability. When polylactic acid or its derivative is used as an arc-extinguishing insulation molding product, the arc cooling performance and arc voltage are further improved by the gas generated by the decomposition of the polylactic acid component by arc exposure, and overcurrent at the time of interrupting a large current is reduced. A circuit breaker that can be suppressed to a low level and that is superior in breaking performance can be obtained. In the present invention, each of the above derivatives includes any conventionally known derivatives.

  Moreover, as resin which uses a polysaccharide as a raw material, the cellulose shown by Formula (11), poly-3-hydroxybutyrate, poly-3-hydroxybutyrate-3-hydroxyvalerate, cellulose acetate, kenaf, etc. Cellulose derivatives, starch, chitin, chitosan and the like can be mentioned.

  These resins constituting the arc-extinguishing insulation molding 35 are, if necessary, two or more aliphatic polyester resins, two or more resins made from polysaccharides, or aliphatic polyester resins and polysaccharides as raw materials. It is possible to use a mixture of two or more types of resins in combination with each other, use these in a mixed manner, or laminate or paste together two or more types of materials molded into a sheet. May be used. The mixing ratio when using two or more kinds of resins, the volume ratio when bonding, and the like are not particularly limited. In the above formulas (1) to (11), n or m in the formula is an independent integer of 1 or more, and R in the formula (11) is H or an alkyl group having 1 to 20 carbon atoms. Represents. Moreover, the said resin can be mixed and used for other resin in order to improve water resistance and moisture resistance, a rigidity improvement, and a flame retardance improvement.

  It is preferable to mix and use a polyamide resin with respect to at least one of the above aliphatic polyester resins and resins made from polysaccharides. By mixing the polyamide resin with the arc-extinguishing insulation molding 35, by the gas generated by the decomposition of the molded article containing at least one of aliphatic polyester resin and polysaccharide-based resin due to arc exposure and the polyamide resin, The ability to cool the arc and the arc voltage are increased, the overcurrent at the time of interruption of a large current can be suppressed low, and the environment resistance, mechanical strength, toughness, interruption performance, flame resistance, etc. are excellent. A circuit breaker can be obtained. Such a polyamide resin is a polymer compound having an amide bond, and includes a polyamide copolymer in the present invention. Specific examples thereof include nylon 6T, nylon 46, nylon 66, nylon MXD6, nylon 610, nylon 6, nylon 11, nylon 12, and copolymer nylon of nylon 6 and nylon 66. Polyamide is a high-strength resin and is mixed to satisfy the pressure strength. Among the specific examples of the polyamide, nylon 6T (melting point: 320 ° C.), nylon 46 (melting point: 290 ° C.) and nylon 66 (melting point: 260 ° C.), which are crystalline polyamides having a high melting point, have high heat deformation temperatures. It is preferable from the viewpoint that the heat resistance of the resin can be improved.

  Moreover, in this invention, it is preferable to mix and use a polyacetal resin with respect to at least any one of the resin which uses the said aliphatic polyester resin and polysaccharide as a raw material. The polyacetal resin is a polymer having an oxymethylene structure as a unit structure, and includes both a homopolymer obtained by polymerizing only formaldehyde and a copolymer containing oxyethylene units. A mixed molded product of at least one of aliphatic polyester resin and polysaccharide-based resin and polyacetal resin is a gas generated by arc of polyacetal in resin and blended material of aliphatic polyester resin and / or polysaccharide as raw material. The arc extinguishing performance is improved by the above, and flame retardancy is imparted to the polyacetal by a resin component other than the polyacetal in the blend. Furthermore, by mixing a polyacetal resin or a polyacetal copolymer with the arc-extinguishing insulating molding, the overcurrent can be further suppressed. As a result, a circuit breaker having excellent breaking performance can be obtained.

  Furthermore, by mixing organic fiber with the arc-extinguishing insulation molding, the mechanical strength of the molding is improved, and the gas generated by the decomposition of the organic fiber itself cools the arc and improves the arc voltage. Overcurrent at the time of current interruption can be suppressed low, and a circuit breaker excellent in interruption performance, environmental resistance, and flame retardancy can be obtained. The organic fiber is preferably a chopped strand type having an average fiber diameter of 1 μm to 20 μm and an average fiber length of about 3 mm or less, more preferably 50 μm to 200 μm. By using organic fibers having such a shape, the effect of mixing organic fibers can be further enhanced.

  Organic fiber is added to improve the mechanical strength, moisture resistance, and environmental resistance of the molded product, and at the same time, improve the arc extinguishing performance by the gas generated by the arc of the organic fiber itself. Can do. Examples of such organic fibers include polyparaphenylene benzoxazole (PBO) fibers such as XYLON (trade name, registered trademark) manufactured by Toyobo Co., Ltd., Kevlar (trade name, registered trademark) manufactured by Toray DuPont, Teijin Para-aramid fibers such as Twaron (trade name, registered trademark), Technora (trade name, registered trademark) of Techno Products Co., Ltd., Metax such as Conex (trade name, registered trademark), manufactured by Teijin Techno Products Ltd. Super-polyamide fibers such as Aramid fiber, Asahi Kasei Fibers Co., Ltd. Cyvalon (trade name), polyarylate fibers such as Vectran (trade name) manufactured by Kuraray Co., Ltd., and Dyneema (trade name) manufactured by Toyobo Co., Ltd. High-strength polyethylene fiber, high-strength polyvinyl alcohol fiber such as Kuraray K-II (trade name) manufactured by Kuraray Co., Ltd., manufactured by Asahi Kasei Corporation Polyacetal fibers such as NAC SD (trade name), polyimide (PI) fibers such as P-84 manufactured by Toyobo Co., Ltd., fibers made of aromatic polyester such as polyphenylene sulfide (PPS) fibers, polyethylene terephthalate (PET), etc. Polyester fiber, Teijin DuPont Films Ltd. Teonex (trade name) fiber, polybutylene terephthalate (PBT) fiber, polytrimethylene terephthalate (PTT) fiber, polypropylene fiber, polyvinyl alcohol fiber, viscose fiber, nylon fiber, Asahi Kasei Examples thereof include plant fibers such as Bemberg (trade name, generic name cupra), polylactic acid fibers, cellulosic fibers, kenaf and the like. Examples of the cellulosic fiber include a case where cellulose fiber is mixed with a polylactic acid resin.

  In addition, ceramic fibers can be mixed with the arc-extinguishing insulation molding, and specific examples include aluminum silicate fibers, aluminum borate whiskers, and alumina whisker ceramics. These ceramic fibers may be used alone or in combination, and the arc extinguishing performance of the arc extinguishing insulation molding can be improved, and the mechanical strength such as arc wear resistance and pressure strength can be improved. Of the ceramic fibers, aluminum silicate fibers, aluminum borate whiskers, alumina whiskers and the like are preferable from the viewpoint of improving arc extinguishing performance and pressure resistance. In particular, the average fiber diameter (average diameter) of the fibers is preferably 1 μm to 20 μm and the aspect ratio is 10 or more from the viewpoint of pressure resistance.

  When mixing and using polyacetal resin, polyamide resin, organic fiber, ceramic fiber, etc. in the arc-extinguishing insulation molding, the mixing ratio is not particularly limited, but relative to the total mass of the arc-extinguishing insulation molding Thus, the total ratio of the aliphatic polyester resin and / or polysaccharide-based resin constituting the arc-extinguishing insulating molding is preferably in the range of 5% to 90%, and is preferably 10% to 60%. It is preferable to mix within a range. When the total amount of the resin or fiber to be mixed satisfies the above range, the mechanical strength such as arc wear resistance, environmental resistance, and pressure resistance of the arc extinguishing ability in the present invention is further improved. Can do. Further, when polylactic acid or a derivative thereof is used as the resin constituting the arc-extinguishing insulating molding as described above, the arc-extinguishing ability is significantly improved when the resin or fiber is mixed.

  In addition, the arc-extinguishing insulation molding may contain other additives such as known stabilizers, antioxidants, oxidation accelerators, ultraviolet absorbers, plasticizers, colorants, fillers, etc., if necessary. Can do.

  The arc-extinguishing insulating molding as described above preferably has a melting point of 90 ° C. or higher and 300 ° C. or lower, and particularly preferably 150 ° C. or higher and 280 ° C. or lower. If the melting point of the arc-extinguishing insulation molding is less than 90 ° C, when the product containing the arc-extinguishing insulation composition is used, the used member melts due to the temperature rise inside the product, and the arc extinguishing performance is hindered. If it exceeds 300 ° C, the moldability may be inferior.

  The arc extinguishing insulation molding can be produced by an existing method. For example, injection molding, extrusion molding, hollow molding (blow molding), thermoforming (vacuum or pressure molding), calendar molding, lamination molding in which two or more types of sheets and films are laminated or bonded together, and processed into a single product, liquid Examples include molding, casting, and powder molding.

  The arc-extinguishing insulation molding 35 manufactured in this way is made of a resin containing at least one of an aliphatic polyester resin and a resin made from a polysaccharide, so that, for example, a gas when exposed to an arc The generated pressure is improved by 10% or more than the conventional arc-extinguishing insulation molding.

  In the present invention, the arc extinguishing insulation molding 35 can be subjected to post-treatment such as chemical treatment or physical treatment for improving functionality such as surface light resistance improvement and weather resistance improvement. Examples of chemical treatment include chemical treatment, solvent treatment, coupling agent treatment, monomer / polymer coating, surface grafting, and the like. Examples of the physical treatment include ultraviolet irradiation treatment, plasma treatment, and ion beam treatment.

  Since the circuit breaker according to the present invention uses the arc-extinguishing insulation molding 35 excellent in gas generation efficiency as described above, its operation performance is improved. That is, it is possible to shorten the time from when an abnormal current starts flowing in the electric circuit until the circuit is interrupted as compared with the conventional circuit breaker. For example, when two plate-like members having a thickness of 20 mm × 30 mm and a thickness of 1 mm are arranged to face each other, the arc-extinguishing insulation molding 35 is exposed to an arc generated when the circuit is interrupted to generate decomposition gas, thereby generating an arc current. And the peak current value can be reduced by 10% or more. Further, by using the arc extinguishing insulation molding, the volume of the casing of the arc extinguishing device can be reduced, and the breaking capacity can be increased. For example, the housing volume can be increased by approximately 30% or more, and the breaking capacity can be increased by approximately twice or more compared to the case where a conventional arc extinguishing insulation molding is used.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these. In addition, the resin etc. which were used by the present Example and the comparative example are described below.
Cellulose acetate: Daicel Finechem, trade name “Aceti”
Polylactic acid: manufactured by Unitika, trade name "Teramac"
Polybutylene succinate adipate: Showa Polymer Co., Ltd., trade name “Bionole 1000”
Polybutylene succinate: Showa Polymer Co., Ltd., trade name “Bionore 3000”
Polycaprolactone: Daicel Chemical Industries, trade name “Cell Green PH”
Polyacetal: Mitsubishi Engineering Plastics, trade name “Iupital”
Nylon 66: manufactured by Ube Industries, trade name “UBE nylon”, average molecular weight: 20,000
Polyethylene terephthalate: Toyobo Co., Ltd., trade name “Viropet”
Polybutylene terephthalate: Made by Mitsubishi Engineering Plastics, trade name “Novaduran”
Aluminum borate whisker: average fiber diameter 1 μm, average fiber length 20 μm
Cellulose fiber: average fiber diameter 16 μm, average fiber length 3 mm
Aramid fiber: Para-type aramid fiber, average fiber diameter 12 μm, average fiber length 3 mm
Glass fiber: average fiber diameter 10 μm, average fiber length 3 mm
(Examples 1-7)
With respect to the resins shown in Table 1, an arc-extinguishing insulation molding 40 mm long × 60 mm wide and 1 mm thick was obtained by injection molding or hot press molding using a mold. The obtained molded product was tested for arc current limiting performance. In Example 5, polycaprolactone cross-linked by radiation was used. FIG. 4 is a schematic view showing an apparatus used for the evaluation of arc-extinguishing insulation molding (arc current-limiting performance test), FIG. 4 (a) is a front sectional view, and FIG. 4 (b) is FIG. It is side surface sectional drawing in IV-IV of a). 4 (a) and 4 (b), the arc extinguishing insulation molding 43, which is a device under test, is placed on a horizontal plate 45 installed on a sample stage 46 provided in a test container 41, Supported by the support 47. The horizontal plate 45 is disposed to face the vertical plate 44. The test was conducted in an electric circuit in which an overcurrent of 300 V and 20 kA flows through the counter electrode 42 having a copper conductor cylinder and electrode contacts. A material having a composition of Ag 60 wt% -WC 36 wt% -graphite 4 wt% was used for the electrode contacts. As the vertical plate 44 and the horizontal plate 45 installed in the test container 41, those obtained by filling unsaturated polyester with 30 wt% of glass fiber (100 wt% of unsaturated polyester and glass fiber) were used.

  In this measurement, when an overcurrent flows in the electric circuit, an arc is generated, and when the arc-extinguishing insulation molding is decomposed and gasified, the maximum current value relative to the peak value of the assumed short-circuit current is the current-limiting peak. Is to be evaluated. Table 1 shows current-limiting peaks when each arc-extinguishing insulation molding is used.

(Comparative Examples 1-2)
In Comparative Examples 1 and 2, nylon 66 and polyethylene terephthalate were used as materials for the arc-extinguishing insulating molding. The arc current-limiting performance test was performed on these molded products. The results are shown in Table 1.

  In Table 1, the parentheses in the resin column indicate the mass parts of each resin. That is, for example, Example 6 shows that 40 parts by mass of polylactic acid and 60 parts by mass of polyacetal were mixed and used. As shown in Table 1, the current limiting peaks of Comparative Examples 1 and 2 are 12.4 kA and 12.8 kA, respectively, whereas in Examples 1 to 7, the current limiting peak is at most 11.2 kA, and the current limiting performance is I understand that it is expensive. In the results of Table 1, the current limiting peaks of the polylactic acid simple substance shown in Example 2 and the nylon 66 simple substance shown in Comparative Example 1 are 10.6 kA and 12.4 kA, respectively. Since the current limiting peak of the resin obtained by mixing 40 parts by mass of polylactic acid and 60 parts by mass of nylon 66 is 11.0 kA, and a reduction in the current limiting peak of 1.4 kA is observed compared to Comparative Example 1, It was confirmed that the effect of reducing the current limiting peak was higher than the result estimated from the results when using. From this result, it was found that when the resin in the present invention is used, a synergistic effect is exhibited when nylon fibers or the like are mixed. Further, when nylon 66 was mixed with polylactic acid, toughness was added to the molded product and the environmental resistance was improved.

  Further, as shown in FIG. 3 by using the arc extinguishing insulation molding manufactured in each of the above embodiments, an insulating container, a fixed contact 34 fixed to the insulating container, and a movable contact that opens and closes by an opening / closing mechanism. It mounted in the circuit breaker of this invention provided with the running conductor which transfers the arc which generate | occur | produced between the interruption | blocking part which consists of 31 and the said contact to the arc extinguishing board 36 piled up in multiple stages. When an overcurrent flows through the circuit breaker, an opening / closing mechanism (not shown) of the movable contact 31 operates to open the movable contact 31, and an arc (between the fixed contact 34 and the movable contact 32) A1) occurred in FIG. This arc A1 travels on the fixed side running conductor 33 in the direction of the arc extinguishing device 37, and then the movable side end of the arc A1 commutates to the movable side running conductor 38 (A2 in FIG. 3). By using each arc extinguishing insulation molding shown in Examples 1 to 7 in Table 1, the entire arc can be quickly introduced into the arc extinguishing device, and the arc resistance in the arc extinguishing device is further increased by the generated gas. As a result, good current limiting performance could be obtained. Further, the performance of the circuit breaker shown in FIG. 3 that does not include a running conductor is also limited in current performance compared to the case of the arc-extinguishing insulation molding used in the conventional comparative examples 1 and 2. The peak could be reduced by 10% or more, and an improvement in the blocking performance was recognized.

(Examples 8 to 11)
In Examples 8 to 11, the material shown in Table 2 was an arc-extinguishing insulation molding. First, a resin constituting an arc-extinguishing insulation molding product such as polyacetal and polylactic acid, and aluminum borate whisker or cellulose fiber as additive, aramid fiber of chop strand (manufactured by Teijin Techno Products Co., Ltd., trade name) ) Were previously dry blended and then kneaded in a twin screw extruder to produce resin pellets. The kneading temperature was 170 to 240 ° C. Next, an arc-extinguishing insulating material molded body, which is a plate-like member having a thickness of 1.0 mm, was produced as a set of two sheets by an injection molding method, and the blocking performance was evaluated.

  For the breaking performance test, a circuit breaker as shown in FIG. 3 simulating an actual machine was prototyped, and the molded body was placed opposite to the vicinity of the contact, and the following overload test and short circuit test were performed.

<Overload interruption test>
A circuit breaker including the arc extinguishing device illustrated in FIG. 2 is energized with a current six times the rated current (for example, 600 A for a circuit breaker for 100 A) in an on state, and the movable contact 22 and the fixed contact 24 are connected. The contact opening distance L (the linear distance between the center of the surface of the movable contact 22 and the fixed contact 24) was 25 mm. Table 2 shows the number of successful interruptions of the arc current among the specified number of times (12 times).

<Short-circuit test>
In the ON state, an overcurrent of 50 kA is applied at a voltage of 230 to 690 V to release the movable contact, and an arc current is generated. Was found to be free of casing defects. When the specified number of times of interruption was successful, “OK” was indicated in Table 2, and when the specified number was not reached, “NG” was indicated in Table 2. Moreover, the presence or absence of damage was confirmed visually. The test conditions were a three-phase 720V / 600A in the overload interruption test and a three-phase 460V / 50kA in the short-circuit test.

(Comparative Examples 3-4)
In Comparative Examples 3 to 4, polybutylene terephthalate alone or glass fiber was used as a material for the arc-extinguishing insulation molding. The overload cutoff test and the short-circuit test were performed on these arc extinguishing insulation moldings. These results are shown in Table 2.

  In Table 2, R1, R2, and Ad in the blending ratio R1 / R2 / Ad indicate the parts by mass of the blended resin 1, resin 2, and additive, respectively. As is apparent from Table 2, in Comparative Examples 3 and 4, arc extinguishing performance is insufficient and pressure strength is insufficient, whereas in Examples 8 to 11, 12 interruption tests were performed. All the success counts were cleared, and there was no problem with interruption and breakage in the short circuit test, and it was a pass. From these results, it can be seen that the circuit breaker provided with the arc-extinguishing insulation molding in the present invention is excellent in the breaking performance. Further, as for the arc-extinguishing insulation moldings obtained in Examples 8 to 11, as in Examples 1 to 7, when the breaking performance was measured in a circuit breaker as shown in FIG. Can be quickly introduced into the arc-extinguishing device, and the arc resistance in the arc-extinguishing device is increased by the generated gas. % Or more can be reduced, and an improvement in the blocking performance was recognized.

  Although the embodiments and examples of the present invention have been described as described above, it is also planned from the beginning to appropriately combine the configurations of the above-described embodiments and examples.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is side surface sectional drawing of the contact vicinity of the arc-extinguishing apparatus in the circuit breaker of this invention. It is a perspective view of the arc-extinguishing apparatus of a circuit breaker. It is side surface sectional drawing of the arc-extinguishing chamber of a circuit breaker. It is the schematic of the apparatus used for evaluation of the insulation molding for arc-extinguishing, (a) Front sectional drawing, (b) Side sectional drawing.

Explanation of symbols

  11, 31 Movable contact, 12, 22, 32 Movable contact, 13 Fixed contact, 14, 24, 34 Fixed contact, 15, 35 Insulation molding for arc extinguishing, 20, 36 Arc extinguishing plate, 21 Notch, 23 Arc, 33 fixed side running conductor, 37 arc extinguishing device, 38 movable side running conductor, 39 exhaust port.

Claims (7)

A fixed contact provided with a fixed contact; a movable contact provided with a movable contact; an open / close mechanism that opens and closes the fixed contact and the movable contact by operating the movable contact; and the fixed contact in a contact state And an arc extinguishing device for extinguishing an arc generated when the movable contact is opened,
The arc extinguishing device, the portion which is exposed to the arc occurring, the circuit breaker arc extinguishing insulator molded product comprising an aliphatic polyester resin is disposed.   The circuit breaker according to claim 1, wherein the arc-extinguishing insulating molding includes a polyacetal homopolymer or a polyacetal copolymer.   The circuit breaker according to claim 1 or 2, wherein the aliphatic polyester resin is polylactic acid or a derivative thereof.   The circuit breaker according to any one of claims 1 to 3, wherein the arc-extinguishing insulating molding includes a polyamide resin.   The circuit breaker according to any one of claims 1 to 4, wherein the arc-extinguishing insulating molding includes an organic fiber.   The circuit breaker according to any one of claims 1 to 5, wherein the arc-extinguishing insulating molding includes at least one of an aluminum silicate fiber, an aluminum borate whisker, and an alumina whisker. The circuit breaker further comprises a plurality of arc extinguishing plates and an arc running conductor,
The circuit breaker according to any one of claims 1 to 6, wherein the arc running conductor transfers the generated arc to the arc extinguishing plate.

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