JP5050389B2 - Arc extinguishing method in a switch - Google Patents

Description

The present invention relates to an arc extinguishing methods definitive the switch. More specifically, in the opening operation of the contact of the switch, it is possible to prevent or reduce the movement of the arc in relation to the movement of the movable contact that occurs when the movable contact leaves the fixed contact built in the arc extinguishing chamber. Further, the present invention relates to a device capable of reducing the surface roughness of fixed contact and movable contact due to arc heat and improving the durability of both contacts.

The arc extinguishing chamber provided in the switch and having a built-in fixed contact is provided with a shutter for cutting an arc generated when the movable contact leaves the fixed contact (see, for example, Patent Document 1). . When the shutter is closed, the arc generated between the two contacts becomes thin and is cut in a very short time, and the energized state between the two contacts is released.
The conventional shutter has a structure capable of automatically closing almost the entire arc-extinguishing chamber opening as shown in FIG. 5 when the movable contact comes out of the shutter.

Utility model registration No. 2536839

  In the conventional device, when the movable contact comes off from the shutter, the shutter closes so as to block almost all the opening of the arc extinguishing chamber as described above. However, the arc is not cut as soon as the shutter is closed. Before the arc is cut, the movable contact moves with respect to both contacts as the movable contact moves away from the fixed contact while passing through a very narrow gap in the contact portion of the closed shutter, and then cut. .

The movement of the arc at that time will be described in detail with reference to FIG.
FIG. 6 shows the movement of the arc when the movable contact leaves the fixed contact in the arc-extinguishing chamber in the conventional arc extinguishing apparatus, (a) is the input state, (b) is the moment when the movable contact is separated from the fixed contact, (c) is an explanatory view of the moment when the shutter is closed, and (d) is an explanatory view of a further separated state.

(1) When the movable contact moves away from the fixed contact by the opening operation from the input state as shown in FIG. 6A, an arc is generated at the moment when the movable contact leaves the fixed contact as shown in FIG. 6B. . This arc occurs between the closest positions of the movable contact and the fixed contact.

(2) Further, when the movable contact moves, the movable contact moves along the surfaces of both contacts so as to connect between the closest positions of the surfaces of both contacts. In addition, the arc and the wall of the arc extinguishing chamber are melted by arc heat to generate arc extinguishing gas.

(3) Then, even when the movable contact is released from the shutter and the shutter is closed as shown in (c), the arc is not immediately cut, and the contact portion of the closed shutter is very narrow as shown in (d). In a state of passing through the gap, the movement becomes thin while continuing the above movement with respect to both contacts as the movable contact moves.
(4) At the same time as the shutter is closed, the pressure in the arc extinguishing chamber suddenly increases due to gas expansion due to arc heat, and high pressure gas is blown from the gap of the shutter to the moving arc to cool the arc. And cut with the wind pressure.

  As described above, with the movement of the movable contact, the arc moves on the surface of both contacts over a wide range (almost the entire surface), so that the surface of both contacts is roughened over a wide range. As a result, the durability of both contacts cannot be sufficiently obtained, for example, the electrical resistance at the contact portion of both contacts increases, and there is a risk of abnormal overheating in the energized state of high-voltage current. It was forced to enlarge. In addition, since the frictional resistance between the two contacts becomes large and the two contacts cannot be opened, there is a possibility of causing a malfunction, so a measure for increasing the operation force is required.

(Object of the present invention)
It is an object of the present invention to prevent movement on both contacts accompanying the movement of the movable contact of the arc that occurs when the movable contact leaves the fixed contact built in the arc extinguishing chamber in the opening operation of the contact of the switch. Or, by reducing the surface roughness of fixed contact and movable contact due to arc heat, the electrical resistance at the contact part of both contacts is prevented from increasing and abnormal overheating is prevented, eliminating the need to increase the size of both contacts. was compactified Te is to provide extinguishing method in an open閉器.
Furthermore, another object of the present invention, a malfunction caused by the roughness of the surface of both contact and to improve to prevent without increasing the operating force of the durability of both contact, consumption in the open閉器It is to provide an arc method.

  Means taken by the present invention to solve the above problems are as follows.

According to the present invention, a fixed contact of a switch is built in an arc extinguishing chamber, and a shutter that is urged inward on a movable contact side of the arc extinguishing chamber and is normally closed with both inner surfaces in contact with each other. An arc extinguishing device that closes the shutter at the same time that the movable contact exits the arc extinguishing chamber when the contact is released,
On the movable contact side of the shutter, there is an introduction cover that is inclined according to the locus of movement of the movable contact,
In the state where the shutter is closed, one end on the side far from the movable contact or the vicinity thereof leads from the inside of the arc extinguishing chamber to the outside of the shutter, and expands by the arc and arc heat generated when the movable contact leaves the fixed contact. To prevent or reduce the movement of the arc with respect to both contact due to the movement of the movable contact by providing a gas ejection hole for ejecting the gas in the arc extinguishing chamber to the outside surrounded by the introduction cover ,
The gas ejection hole (79) is an arc extinguishing device (7) provided in the side wall (78) on the introduction cover (77) side of the side wall of the shutter chamber (73) in which the shutter (76) is accommodated. In a switch equipped with
When the contact (4, 5) of the switch (S) is opened, the arc (E) generated when the movable contact (5) moves away from the fixed contact (4) closes the shutter (76). In the arc extinguishing chamber (71), the gas flow expands instantaneously due to the arc heat and flows toward the gas ejection hole (79), and passes through the gas ejection hole (79), so that the fixed contact (4) and the movable contact (5) At the same time, the same gas ejection hole (79) is caused by the expansion of the gas against the arc (E) that is connected between both contacts (4, 5) through the gas ejection hole (79). High-pressure gas ejected through is blown, and the arc (E) is cut by the cooling effect of this gas and the stretching effect of the arc (E).
It is extinguishing method in switch.

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  The shape of the gas ejection holes is, for example, a circular shape or a square shape, but is not particularly limited as long as the arc passes and gas ejection effective for arc cutting can be performed. Further, the number and size of the gas ejection holes are not particularly limited as long as the arc passes and gas can be efficiently ejected for arc cutting.

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(Function)
A description will be given of the operation of this onset Akira. Here, each constituent element used in the description is assigned in correspondence with a reference numeral given to each part in the embodiment described later, and this reference sign is described in each claim of the claims. As in the case of the reference numerals, this is merely to facilitate understanding of the description, and the meaning of each component is not limited to the above-described parts.

When the contact (4,5) of the switch (S) is opened, if the movable contact (5) is separated from the fixed contact (4), the arc (E) between the closest positions of both contacts (4,5) To be connected.
When the movable contact (5) moves further away and the shutter (76) closes, the gas in the arc extinguishing chamber (71) inside the shutter (76) instantaneously expands due to the arc heat, and the gas ejection hole (79 A gas flow toward) occurs.
The arc (E) is pushed by the gas flow and moves so as to connect both contacts (4, 5) through a path passing through the gas ejection hole (79).

  Since the arc (E) is limited to the path through the gas ejection hole (79), it does not move between the closest positions of both contacts (4,5), and the arc that leads to both contacts (4,5) The position of (E) is almost constant even if the movable contact (5) moves further away, so that the arc (E) is detoured so that it is elongated with the movement of the movable contact (5). It is.

  At the same time, with respect to the arc (E) connected between the two contacts (4, 5) through the gas ejection hole (79), the high-pressure gas ejected through the same gas ejection hole (79) due to the expansion of the gas is The arc (E) is cut by the cooling effect of the gas and the stretching effect of the arc (E). In addition, since the gas at this time is intensively sprayed on the arc (E) without waste, higher interruption performance can be obtained.

  As described above, by moving the arc (E) to the path through the gas ejection hole (79), the movement of the arc (E) on both contacts (4,5) accompanying the movement of the movable contact (5) Can be prevented or reduced. As a result, it is possible to prevent surface roughness in a wide range of the fixed contact (4) and the movable contact (5) due to arc heat as in the prior art, and to improve the durability of both contacts (4, 5).

  Further, the electrical resistance at the contact portion of both contacts (4, 5) is not increased, and abnormal overheating of both contacts (4, 5) is prevented. Therefore, it is not necessary to increase the size of both contacts (4, 5) to withstand abnormal overheating, and the size of both contacts (4, 5) can be reduced. Furthermore, it is possible to prevent malfunctions caused by rough surfaces of both contacts (4, 5) without increasing the operating force, and to improve the durability of both contacts (4, 5)). It becomes possible.

  In addition, since the gas ejection hole (79) is provided at the movable contact (5) of the closed portion and one end on the far side in the state where the shutter (76) is closed, both the contacts (4, 5) are provided. When opened, the effect of extending the arc (E) accompanying the movement of the movable contact (5) is large, the arc (E) becomes thin and easily cut, and a stable interruption performance can be obtained in a shorter time. Therefore, the effect of preventing the surface roughness of both contacts (4, 5) and improving the durability is more excellent.

(A) According to the present invention, when the contact of the switch is opened, the arc generated when the movable contact leaves the fixed contact is moved to the path through the gas ejection hole by the expanding gas toward the gas ejection hole. The movement of the arc with respect to both contacts accompanying the movement of the movable contact can be prevented or reduced. As a result, it is possible to reduce the surface roughness in a wide range of fixed contact and movable contact due to arc heat as in the prior art, so the electrical resistance at the contact portion of both contacts does not increase, and abnormal overheating of both contacts Is prevented. Therefore, it is not necessary to increase the size of the two contacts in order to withstand abnormal overheating, and the two contacts can be made compact.

(B) Since surface roughness in a wide range of fixed contact and movable contact due to arc heat can be reduced, malfunctions caused by surface roughness of both contacts can be prevented without increasing the operating force. And the durability of both contacts can be improved.

(C) Since the high-pressure gas ejected through the same gas ejection hole can be intensively sprayed without waste to the arc connected between the two contacts through the gas ejection hole, until the arc is cut This shortens the time required to stabilize the shut-off performance.

(D) Since the gas ejection hole is provided at or near one end on the far side with the movable contact of the closed portion when the shutter is closed, the effect of extending the arc accompanying the movement of the movable contact when the contact is released Larger, the arc becomes thinner and more easily cut, and a stable interruption performance in a shorter time can be obtained. Therefore, the effect | action which prevents the surface roughness of both contacts and improves durability is more excellent.

  The present invention will be described in detail based on the embodiments shown in the drawings.

FIG. 1 shows the structure of an arc extinguishing apparatus according to the present invention, (a) is a longitudinal sectional view, (b) is an AA sectional explanatory view in (a),
FIG. 2 shows the movement of the arc when the movable contact moves away from the fixed contact in the arc extinguishing chamber, (a) is the moment when the shutter is closed, (b) is an explanatory diagram of a further separated state,
FIG. 3 is a front view showing the outer shape of the switch according to the present invention,
4 is a cross-sectional view taken along the line BB in FIG.

  First, the structure of the switch S according to the present embodiment will be described with reference to FIGS. 3 and 4. Since the switch S has a general structure except for the arc extinguishing device 7 which is a characteristic part of the present invention, the structure of these parts is only described or explained. Is omitted.

  The switch S is introduced through a sealed case 1, bushings 2, 3 for connecting distribution lines provided at three locations opposite to the upper and lower sides of the case 1, and each bushing 2 on one side. Connected to the distribution line, connected to the distribution line introduced through the fixed contacts 4 provided at three locations in the case 1, the arc extinguishing device 7 covering each fixed contact 4, and the respective bushings 3 on the other side, A movable contact 5 that is pivotally provided at three locations in the case 1 and that performs a closing / opening operation with respect to each fixed contact 4, a drive mechanism unit 6 that rotates each movable contact 5, and an operation of the drive mechanism unit 6 The movable contact 5 is provided with an operation unit (not shown) for manually or automatically turning on and off.

  The arc extinguishing device 7 employs a shutter system that closes a shutter 76 (described later) when the movable contact 5 comes out of the arc extinguishing chamber 71 when the contact is released. The arc extinguishing device 7 according to the present invention will be described in detail later.

  The fixed contact 4 is fixed to the conductor 40 constituting the distribution line introduced from each bushing 2. The fixed contact 4 is composed of rising portions 42 fixed to both side portions of the conductor 40, the tip side of each rising portion 42 is provided so as to be narrowed, and the tip portion is outside. It is rounded to warp. An input space is provided between the start-up portions 42. A contact spring 44 that reinforces the spring property of the raised portion 42 is provided in close contact with the outer surface of each raised portion 42 of the fixed contact 4.

A fixed contact base 70 constituting the arc extinguishing device 7 is fixed below the conductor 40. An arc extinguishing chamber 71 whose lower side is open is fixed to the upper opening side of the fixed contact table 70. The fixed contact table 70 and the arc extinguishing chamber 71 are made of insulating plastic.
A through-hole 72 having a rectangular shape in plan view through which the tip of the movable contact 5 can go in and out is provided above the fixed contact 4 in the top of the arc extinguishing chamber 71.

  A shutter chamber 73 made of insulating plastic is fixed to the upper portion of the arc extinguishing chamber 71 with bolts. At the top of the shutter chamber 73, an entrance / exit 74 through which the tip of the movable contact 5 can enter and exit is provided in the same manner as the through-hole 72. In the space inside the shutter chamber 73, there are accommodated shutters 76 and 76, which are each biased inward by a spring 75 and normally closed by contacting both inner surfaces.

  A gas ejection hole 79 is provided in the vertical direction in FIG. 2 on one side wall 78 on the side that guides each shutter 76 among the side walls of the shutter chamber 73. The gas ejection hole 79 communicates with the lower through-hole 72 and the upper entrance / exit 74, whereby the arc passes through the fixed contact 4 → the through-hole 72 → the gas ejection hole 79 → the entrance / exit 74 → the movable contact 5. Can pass through. Further, the gas that is expanded by the arc heat inside the shutter chamber 73 is also ejected to the outside through the gas ejection hole 79.

  In the present embodiment, the gas ejection holes 79 are always open regardless of the open / closed state of each shutter 76. However, as long as at least the shutters 76 are closed, the gas ejection holes 79 of the present embodiment can be used. It is not limited to the structure.

  In addition, an introduction cover 77 that is inclined in accordance with the trajectory of the movable contact 5 is provided on the upper portion of the shutter chamber 73 as shown in the drawing. The lower part of the shutter chamber 73 is opened, and the internal space communicates with the through-hole 72 of the arc extinguishing chamber 71 top.

  The movable contact 5 is fixed to a conductor 50 constituting a distribution line route introduced from each bushing 3. The movable contact 5 is rotated by a drive mechanism unit 6 that employs a link mechanism or the like, and has a structure for performing a closing / opening operation with the fixed contact 4. The movable contact 5 includes a base 51 that rotates about a shaft 52 and a contact plate 53 that is connected to the tip of the base 51. The contact plate 53 is formed in a curved shape and is obtained by silver plating on a copper plate.

(Function)
The operation of the arc extinguishing device 7 according to the present embodiment and the switch S having the same will be described.
(1) When the movable contact 5 is separated from the fixed contact 4 when the fixed contact 4 and the movable contact 5 of the switch S are opened, the arc E is generated between the two contacts 4 and 5 that are closest to each other. (Reference: FIG. 6 (b)).
(2) When each of the shutters 76 is closed by moving the movable contact 5 further away, the gas in the arc extinguishing chamber 71 inside the shutter 76 is instantaneously expanded by the arc heat, and the gas flows toward the gas ejection hole 79. Occurs.

(3) The arc E is pushed by this gas flow, and moves so as to connect both contacts 4 and 5 through a path passing through the gas ejection hole 79 (see FIG. 2A). The position where the arc E is first connected to the movable contact 5 is the surface of the arc portion on the tip side of the contact plate 53 as shown in FIG. 2 (a), and immediately thereafter to the tip corner of the contact plate 53. Move a little. Further, the position connected to the fixed contact 4 of the arc E is the end of the fixed contact 4 on the side close to the gas ejection hole 79, and does not change thereafter.

(4) Since the arc E is limited to the path passing through the gas ejection hole 79, the arc E connected to the contacts 4 and 5 without moving between the closest positions of the contacts 4 and 5 as in the prior art. Even if the movable contact 5 moves further away, the position is substantially constant as described above. For this reason, the arc E is extended in a thin manner in accordance with the movement of the movable contact 5 in a so-called detour. In addition, since the gas ejection hole 79 is provided in the vicinity of one end of the closed portion (the contact portion of the shutters 76) on the side far from the movable contact 5, the effect of extending the arc E accompanying the movement of the movable contact 5 is provided. However, it is larger than the case where it is provided at another location such as the near side, and the arc becomes thinner and is likely to be cut.

(5) At the same time, a high-pressure gas ejected through the same gas ejection hole 79 is blown against the arc E connected through the gas ejection hole 79 and connected between the contacts 4 and 5 by the expansion of the gas. The arc E is cut by the cooling effect of the above and the further extending effect of the arc E. In addition, since the gas at this time is intensively sprayed with respect to the arc E without waste, higher interruption | blocking performance is obtained.

  Further, as described above, by moving the arc E to the path passing through the gas ejection hole 79, the movement of the arc E with respect to both the contacts 4 and 5 accompanying the movement of the movable contact 5 can be prevented or reduced. As a result, it is possible to prevent or reduce surface roughness in a wide range of the stationary contact 4 and the movable contact 5 due to arc heat as in the prior art, so that the electrical resistance at the contact portion of both the contacts 4 and 5 does not increase. The abnormal overheating of both contacts 4 and 5 is prevented.

Therefore, it is not necessary to increase the size of both contacts 4 and 5 to withstand abnormal overheating, and the both contacts 4 and 5 can be made compact.
In addition, since the malfunction due to the rough surface of the both contacts 4 and 5 can be prevented without increasing the operating force, the durability of the both contacts 4 and 5 can be improved.

  Note that the terms and expressions used in the present specification are merely explanatory and not restrictive, and do not exclude terms and expressions equivalent to the above terms and expressions. The present invention is not limited to the illustrated embodiment, and various modifications can be made within the scope of the technical idea.

The structure of the arc-extinguishing apparatus which concerns on this invention is shown, (a) is a longitudinal cross-sectional view, (b) is AA cross-section explanatory drawing in (a). The movement of an arc when a movable contact leaves | separates from the fixed contact in an arc extinguishing chamber is shown, (a) is the explanatory view of the state which left | separated further, the moment (a) closed the shutter. The front view which shows the external shape of the switch concerning this invention. BB sectional drawing in FIG. Cross-sectional explanatory drawing which shows the structure of the shutter of the conventional arc-extinguishing apparatus. In the conventional arc extinguishing apparatus, the movement of the arc when the movable contact is separated from the fixed contact in the arc extinguishing chamber is shown, (a) is the input state, (b) is the moment when the movable contact is separated from the fixed contact, (c) is (D) is an explanatory view of a further separated state at the moment when the shutter is closed.

DESCRIPTION OF SYMBOLS S Switch 1 Case 2 Bushing 3 Bushing 4 Fixed contact 40 Conductor 42 Raising part 44 Contact spring 5 Movable contact 50 Conductor 51 Base body 52 Shaft 53 Contact board 6 Drive mechanism part 7 Arc extinguishing device 70 Fixed contact stand 71 Arc extinguishing chamber 72 Through-hole 72 Through-hole 73 Shutter chamber 74 Entrance / exit 75 Spring 76 Shutter 77 Introduction cover 78 Side wall 79 Gas ejection hole E Arc

Claims (1)

The stationary contact (4) of the switch (S) is built in the arc extinguishing chamber (71), and the movable contact (5) of the arc extinguishing chamber (71) is energized inward and normally both The shutter (76) is closed by contacting the inner surface of the shutter, and when the contact is released, the movable contact (5) comes out of the arc extinguishing chamber (71) and simultaneously closes the shutter (76). Arc device (7),
On the movable contact side of the shutter (76), there is an introduction cover (77) that is inclined according to the trajectory of the movable contact (5),
In the state where the shutter (76) is closed, the movable contact (5) and one end on the far side or in the vicinity thereof lead from the inside of the arc extinguishing chamber (71) to the outside of the shutter (76), and the fixed contact (4) A gas ejection hole (79) for ejecting the gas in the arc extinguishing chamber (71) expanded by the arc and arc heat generated when the movable contact (5) is separated from the outside is surrounded by the introduction cover (77). To prevent or reduce the movement of the arc against both contacts with the movement of the movable contact ,
The gas ejection hole (79) is an arc extinguishing device (7) provided in the side wall (78) on the introduction cover (77) side of the side wall of the shutter chamber (73) in which the shutter (76) is accommodated. In a switch equipped with
When the contact (4, 5) of the switch (S) is opened, the arc (E) generated when the movable contact (5) moves away from the fixed contact (4) closes the shutter (76). In the arc extinguishing chamber (71), the gas flow expands instantaneously due to the arc heat and flows toward the gas ejection hole (79), and passes through the gas ejection hole (79), so that the fixed contact (4) and the movable contact (5) At the same time, the same gas ejection hole (79) is caused by the expansion of the gas against the arc (E) that is connected between both contacts (4, 5) through the gas ejection hole (79). High-pressure gas ejected through is blown, and the arc (E) is cut by the cooling effect of this gas and the stretching effect of the arc (E).
Arc extinguishing method in a switch.

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