TWI423546B - Bushing - Google Patents

Description

bushing

The present invention relates to a bushing which is provided, for example, to a vacuum circuit breaker or the like which is disposed in a casing of a switchboard in a pull-out manner, and is detachably provided on the back side thereof as The main circuit is broken.

The current energizing portion of the main circuit to which the device such as the vacuum breaker is connected must set the temperature rise value when the rated current is energized to a predetermined value or less according to the specification. Further, from the viewpoint of safety (protection level), in order to protect a person who cannot approach a dangerous part or protect a device in which solid foreign matter does not intrude into the device, it is covered with a casing or a partition wall or the like. The entire device. Therefore, in the energization portion of the main circuit, it is necessary to have structural considerations for satisfying the condition of the temperature rise value.

In the conventional structure in which the temperature rise of the main circuit breaking portion is considered, for example, as shown in Fig. 7, there is disclosed a technique in which a side of the insulating layer 21 through which the center conductor 20 is inserted is coaxially formed into a square shape. The small-diameter cylindrical portion 21a and the large-diameter cylindrical portion 21b are provided with a vent 23 corresponding to a position facing the fitting portion of the contact 22 and the center conductor 20, above and below the tubular portion 21a, on the outer side. The tubular portion 21b is provided with a vent 24 above and below the front side, and the cooling effect is enhanced by the convection of the cooling gas, which is heated by the heat generated from the contact portion of the contact member 22 and the center conductor 20 (for example, refer to the patent document) 1).

(previous technical literature) (Patent Literature)

(Patent Document 1) Japanese Patent Laid-Open No. Hei 10-322819 (page 3, pages 1, 2)

In the conventional main circuit breaking portion (hereinafter referred to as a bushing) described in Patent Document 1, since the vent hole is provided in the vertical direction on the side surface of each of the cylindrical portions protruding from the insulating layer 21, for example, When the insulating layer 21 is formed by injection molding, the structure of the mold is retracted, and the processing takes time and expense.

Further, in the shape described in Patent Document 1, since the air is circulated only on the side of the connection portion to which the contact member such as the circuit breaker is connected, only the connection portion side is cooled, and the connection portion cannot be cooled. The problem of an increase in temperature of the opposite side (i.e., the side to which the main circuit conductor such as a bus bar is connected) is suppressed.

The present invention has been made in order to solve the above problems, and an object of the invention is to provide a bushing which can suppress a temperature rise at the time of energization with a simple configuration and which has a good cooling effect.

The bushing of the present invention is disposed on a wall surface on the back side of the fixing frame on which the opening and closing device is placed, and has an insulating cylinder and a center conductor that is inserted into the center of the insulating cylinder, and is connected to one end of the center conductor. The main circuit terminal of the machine is connected to the main circuit conductor at the other end of the center conductor, wherein the insulating cylinder has a cylindrical portion, a flange portion which is located at one end side of the tubular portion and is fixed to the wall surface, and is located at the other end side. A mounting portion of the center conductor is mounted near the open end, and the center guiding system has a terminal connecting portion that protrudes from the mounting portion toward the inside of the tubular portion and is connected to the main circuit terminal, and a main connecting portion that is attached to the mounting portion and is connected to the outer end surface The main circuit connecting portion of the conductor is provided with a vent hole penetrating in a direction orthogonal to the axis of the center conductor on the mounting portion side of the main circuit connecting portion.

According to the bush of the present invention, since the insulating cylinder of the bushing has a cylindrical portion, a flange portion which is located at one end side of the tubular portion and is fixed to the wall surface, and an opening end which is located at the other end side and is mounted with the center conductor The central guiding system has a terminal connecting portion that protrudes toward the inner side of the tubular portion and is connected to the main circuit terminal, and a main circuit connecting portion that is attached to the mounting portion and has a main circuit conductor connected to the outer end surface, and is mainly Since the vent hole penetrating in the direction orthogonal to the axis of the center conductor is provided on the mounting portion side of the circuit connecting portion, the through circuit can be directly cooled by a simple configuration, so that the temperature rise of the conducting portion can be suppressed and the bushing can be efficiently cooled. unit.

(Embodiment 1)

Hereinafter, the bushing according to the first embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a side cross-sectional view showing a state in which a bush is disposed on a back surface of a fixing frame in which a vacuum circuit breaker is housed, and a vacuum circuit breaker is connected to the bushing. Fig. 2 is a perspective view showing the bushing of Fig. 1. Figure 3 is a side cross-sectional view of Figure 2.

Here, a vacuum circuit breaker is taken as an example of a bushing housed in a switchboard, and a bushing using a connection portion (breaking portion) of a main circuit conductor on the side of the vacuum circuit breaker and the switchboard will be described.

The interior of the frame (not shown) constituting the switchboard is divided into a circuit breaker chamber in which a circuit breaker is housed, a bus bar room in which a bus bar is housed, and a cable room in which a cable is housed. As shown in Fig. 1, the vacuum circuit breaker 2 disposed in the fixed frame 1 constituting the circuit breaker chamber includes a trolley 3 having a wheel and movable in the front-rear direction, and an insulating frame 4 fixed to the trolley 3; 5, is housed inside the insulating frame 4; and a driving mechanism (not shown) is connected to the movable side contact (not shown) of the vacuum valve 5, and the movable side contact is disconnected from the fixed side contact (not shown) Graphic). Further, the upper main circuit terminal 6 is led out from the fixed side contact, and the lower main circuit terminal 7 is led out from the movable side contact, and is fixed to the insulating frame 4, respectively. At the end of each of the main circuit terminals 6, 7, a contact member 8 of a finger shape, which will be described later, is provided.

The upper bushing 10 and the lower bushing 11 are disposed on the wall surface of the fixed frame 1 on the back side of the vacuum circuit breaker 2 so as to face the upper main circuit terminal 6 and the lower main circuit terminal 7.

In the first diagram, the state in which the main circuit terminals 6, 7 and the upper and lower bushings 10, 11 of the vacuum circuit breaker 2 are connected is connected, and if the vacuum circuit breaker 2 is pulled out to the front side with the trolley 3, From the above-described connection state to the open state, and further formed, the vacuum circuit breaker 2 can be taken out from the front of the casing to the outside of the switchboard.

Fig. 2 is a perspective view showing the bushing structure of Fig. 1, and Fig. 3 is a side cross-sectional view of the bushing of Fig. 2. Since the upper bushing 10 and the lower bushing 11 have substantially the same shape, the upper bushing 10 will be described below as an example.

In the second and third figures, the upper bushing 10 includes an insulating cylinder 12 made of an insulating material such as an epoxy resin, and a center conductor 13 inserted through the center of the insulating cylinder 12.

The insulating cylinder 12 has a rectangular tubular portion 12a, a rectangular flange portion 12b that is provided on one of the open end sides of the tubular portion 12a and that is attached to the fixed frame 1, and is disposed in a direction perpendicular to the axis of the tubular portion 12a. The mounting portion 12c of the center conductor 13 is attached to the inner side of the open end of one of the sides.

The center conductor 13 has a cylindrical terminal connecting portion 13a that protrudes from the mounting portion 12c toward the inside of the tubular portion 12a and is connected to the upper main circuit terminal 6 of the vacuum circuit breaker 2, and is attached to the mounting portion 12c and is attached to the outer end surface (installed) On the opposite side of the surface, a main circuit connecting portion 13b of a main circuit conductor such as a bus bar or a cable (not shown) is connected. (From the mounting surface to the mounting portion 12c, the inside of the tubular portion is the terminal connecting portion 13a, and the opening portion is the main circuit connecting portion 13b.)

The terminal connecting portion 13a and the main circuit connecting portion 13b may be formed of the same member, and may be joined to individual producers by brazing or the like.

As shown in FIG. 3, a finger-shaped contact member 8 is provided on the front end side of the upper main circuit terminal 6 on the side of the vacuum circuit breaker 2, and the terminal connecting portion 13a of the center conductor 13 is in sliding contact with the contact member 8. Electrical connection.

The contact member 8 is attached to the outer periphery of the upper main circuit terminal 6 and the lower main circuit terminal 7 before the vacuum circuit breaker 2, and a plurality of contact pieces 8a are assembled in a ring shape, and are disposed on the outer peripheral side of the contact piece. The spring 8b is biased toward the inner diameter direction. By the spring force, a contact load is applied so that one convex portion on the inner circumferential side of the contact piece 8a comes into contact with the outer circumference of the terminal connection portion 13a of the center conductor 13.

The present invention is characterized in that a vent hole is provided in the main circuit connecting portion 13b of the center conductor 13, and a communication port is provided in the terminal connecting portion 13a. Therefore, the details thereof will be described next.

The vent opening is opened in a direction orthogonal to the axis of the center conductor 13 (that is, a direction parallel to the mounting surface of the mounting portion 12c), and as shown in FIGS. 2 and 3, the vent hole 14a penetrating in the vertical direction, The vent holes 14b penetrating in the horizontal direction are formed in a cross shape and connected to each other at the center portion. When the terminal connecting portion 13a and the main circuit connecting portion 13b are formed by different members, the vent holes 14a and 14b are provided with a cross section on the mounting surface side of the main circuit connecting portion 13b. The groove of the glyph can be used.

Further, as shown in the side cross-sectional view of Fig. 3, the center of the terminal connecting portion 13a is oriented in the axial direction, and a communication port 14c that communicates from the central portion of the vent ports 14a and 14b to the inner side of the tubular portion 12a is formed.

Next, the action of the vent holes 14a and 14b and the communication port 14c of the bushing configured as above will be described.

The temperature of the vacuum circuit breaker and the main circuit conductor portion rises due to the heat generated by the Joule heat generated by the energization. However, since the inside of the vacuum circuit breaker and the main circuit conductor portion are required to be protected from inaccessibility and prevention of intrusion of solid foreign matter, almost all of them are covered by a certain form. Therefore, the heat dissipation effect is low, and there must be considerations to meet the conditions of the temperature rise value.

Therefore, in the present invention, as described above, the vent ports 14a and 14b and the communication port 14c are provided in the center conductor 13 of the bushing 10.

Although the temperature of the bushing portion 10 rises due to the current flowing through the center conductor 13 of the bushing 10, the air is sucked and exhausted from the air vents 14a and 14b, and the main circuit connecting portion 13b is cooled and the terminal connecting portion is cooled. The 13a side is also cooled by heat conduction.

Further, by providing the communication port 14c, as shown in Fig. 4, the communication port 14c is connected to the vent holes 14a, 14b, and air is formed from the back side of the fixed frame 1 to the accommodating side of the vacuum circuit breaker 2 Since the air flows, for example, as shown by the arrow, the connection portion between the terminal connecting portion and the contact of each main circuit terminal can be directly cooled.

In addition, the air inside the circuit breaker can be inhaled/exhausted via the upper and lower bushings 10, 11 and a higher cooling effect can be obtained.

Further, the center conductor 13 belonging to the current-carrying portion is provided with a vent port and a communication port, and the vent port and the communication port are opened in a direction inaccessible to a human finger or the like, so that the safety of the energized portion (protection level) is satisfied. At the same time, it can also meet the completeness (protection level) of the vent and communication port for inhaling/exhausting air.

Further, in the above description, the shape of the main circuit connecting portion 13b of the center conductor 13 is formed in a rectangular shape when viewed in the axial direction, but is not limited thereto, and may be circular. At this time, the tubular portion 12a may be formed as a cylinder.

Further, although the vent port is provided with two portions (14a, 14b) in the horizontal direction and the vertical direction, any portion may be provided.

Further, although the communication port 14c is provided at the center of the terminal connecting portion 13a, the communication port 14c may not be provided when the energizing capacitance is small.

As described above, the bush according to the first embodiment is disposed on the wall surface on the back side of the fixing frame on which the opening and closing device is placed, and has an insulating cylinder and a center conductor inserted in the center of the insulating cylinder, and the center conductor One of the end portions is connected to the main circuit terminal of the opening and closing machine, and the bushing having the main circuit conductor connected to the other end of the center conductor has a cylindrical portion, a convex portion located on one end side of the cylindrical portion, and fixed to the wall surface. The edge portion and the mounting portion of the center conductor are disposed near the open end of the other end side, and the center guiding system has a terminal connecting portion that protrudes from the mounting portion toward the inner side of the tubular portion and is connected with the main circuit terminal, and is mounted and mounted The main circuit connecting portion of the main circuit conductor is connected to the outer end surface, and the vent hole penetrating in the direction orthogonal to the axis of the center conductor is provided on the mounting portion side of the main circuit connecting portion. The energization unit performs direct cooling, and can suppress the temperature rise of the energization portion and efficiently cool the liner.

Further, since the vent hole is formed in a cross shape in the horizontal direction and the vertical direction, the air from the outside can be efficiently sucked/exhausted inside the center conductor of the bushing, so that a high cooling effect can be obtained.

Further, since the communication port that communicates from the vent port to the inner side of the tubular portion is provided at the center of the terminal connecting portion of the center conductor, the air on the opening and closing machine side can be inhaled/exhausted via the bushing, in particular, The terminal contact portion whose temperature rises high is effectively cooled, so that the temperature rise of the energized portion can be suppressed, and a high cooling effect can be obtained.

(Embodiment 2)

Fig. 5 is a perspective view showing a bushing according to a second embodiment of the present invention. Figure 6 is a side cross-sectional view of the bushing of Figure 5. The connection structure of the vacuum circuit breaker 2 including the vacuum circuit breaker 2 disposed in the fixed frame 1 is the same as that of the first embodiment of the first embodiment. Therefore, the illustration and description are omitted, and the differences will be mainly described.

The connection system of the electrical equipment that constitutes the switchboard must be sufficiently to withstand the rated current, the rated short-time withstand current, and the rated peak withstand current. Further, the insulating support portion of the connection conductor must be a support structure that sufficiently withstands the electromagnetic force when the short-circuit current is energized or the urging force at the time of opening and closing. For the above reasons, it is known that the center conductor of the bushing must sufficiently secure the cross-sectional area and securely fix it so as to be able to withstand the energization or the punching force.

In the structures of Figs. 2 and 3 described in the first embodiment, the cooling effect can be sufficiently expected. However, from the above viewpoint, there is a need for further work.

Therefore, in the second embodiment, as shown in Figs. 5 and 6, the vent hole provided in the center conductor 13 of the upper bushing 10 is provided only as a mounting surface of the main circuit connecting portion 13b in the vertical direction, for example. On the other hand, the vent hole 14a is provided with a vent slit that penetrates in a direction parallel to the axis of the center conductor 13 at a portion of the mounting portion 12c of the insulating tube 12 that is further outward than the outer circumference of the main circuit connecting portion 13b. 15. The ventilation slit 15 is a condition that the safety (protection level) can be satisfied by setting the size (width) of a part of the human body (finger or the like).

Next, the action of this configuration will be described.

By providing the vent opening 14a with only a minimum of, for example, the vent opening provided in the center conductor 13 of the bushing, the current capacitance and the supporting portion (the terminal connecting portion 13a and the main circuit connecting portion 13b) can be hardly swayed. In the case of the strength of the portion, the center conductor 13 is cooled, and the vent slit 15 penetrating through the mounting portion 12c of the insulating cylinder 12 can be formed in the same manner as described in the fourth embodiment of the first embodiment. Through the flow path of the air inside the bushings 10 (and 11) and the vacuum circuit breaker side and the main circuit conductor side, air inhalation/exhaustion of the air inside the insulating frame 4 of the vacuum circuit breaker 2 can also be performed. And a higher cooling effect can be obtained.

Further, since the ventilation slit 15 provided in the attachment portion 12c of the insulating cylinder 12 is formed in the axial direction of the insulating cylinder 12 (the pressing direction of the forming process), it is not necessary to perform special additional processing at the time of molding, and can be easily and inexpensively performed. Processing.

Further, in the above description, the ventilation slits 15 are provided in four places on the right and left sides of the main circuit connection portion 13b, but may be, for example, two portions on the left and right or on the upper and lower sides.

Further, the vent hole provided in the center conductor 13 may be provided in the horizontal direction, and if it is structurally (and electrically), it may be provided in two places in the vertical direction and the horizontal direction as in the first embodiment. A communication port is provided at the center of the terminal connecting portion 13a.

As described above, according to the bush of the second embodiment, in addition to the configuration of the first embodiment, the venting slit that penetrates the axial direction of the center conductor is provided in the mounting portion of the insulating cylinder, and therefore, in addition to the effect of the first embodiment, The air intake/exhaust of the air on the machine side can be opened and closed, and a higher cooling effect can be obtained.

Further, by minimizing the vent hole provided in the center conductor, it is possible to provide a bushing which secures the current capacitance of the center conductor and the strength of the support portion and which has a good cooling effect.

Further, since the vent slit is provided in the axial direction of the insulating cylinder, the production of the insulating cylinder does not require special additional processing, and can be easily performed by molding.

1. . . Fixed frame

2. . . Vacuum circuit breaker

3. . . Trolley

4. . . Insulating frame

5. . . Vacuum valve

6. . . Upper main circuit terminal

7. . . Lower main circuit terminal

8. . . Contact

8a. . . Contact piece

8b. . . Ring spring

10. . . Upper bushing

11. . . Lower bushing

12. . . Insulation cylinder

12a. . . Tube

12b. . . Flange

12c. . . Installation department

13. . . Center conductor

13a. . . Terminal connection

13b. . . Main circuit connection

14a, 14b. . . Vent

14c. . . Connecting port

15. . . Ventilation slit

Fig. 1 is a side cross-sectional view showing a main circuit breaking portion of a vacuum circuit breaker to which a bush according to a first embodiment of the present invention is applied.

Fig. 2 is a perspective view for explaining the bushing structure of Fig. 1.

Figure 3 is a side cross-sectional view of the bushing of Figure 2.

Fig. 4 is an explanatory view showing the flow of air using the wall surface of the bush of the first embodiment.

Fig. 5 is a perspective view showing a bushing according to a second embodiment of the present invention.

Figure 6 is a side cross-sectional view of the bushing of Figure 5.

Figure 7 is a side cross-sectional view of a conventional bushing.

10. . . Upper bushing

12. . . Insulation cylinder

12a. . . Tube

12b. . . Flange

12c. . . Installation department

13. . . Center conductor

13a. . . Terminal connection

13b. . . Main circuit connection

14a, 14b. . . Vent

Claims (4)

A bushing is disposed on a wall surface on a back side of a fixing frame on which an opening and closing device is placed, and has an insulating cylinder and a center conductor that is inserted into a center of the insulating cylinder, and the one end of the center conductor is connected to the front end a main circuit terminal of the opening and closing device, wherein a main circuit conductor is connected to the other end of the center conductor, and the insulating cylinder has a tubular portion, a flange portion located on one end side of the tubular portion and fixed to the wall surface, and a position a mounting portion of the center conductor is mounted in the vicinity of the opening end of the other end side, and the center guiding system has a terminal connecting portion that protrudes toward the inner side of the cylindrical portion and is connected to the main circuit terminal, and is mounted on the mounting portion The mounting portion is connected to the main circuit connecting portion of the main circuit conductor at the outer end surface, and a vent hole penetrating in a direction orthogonal to the axis of the center conductor is provided on the mounting portion side of the main circuit connecting portion. The bushing according to claim 1, wherein the vent hole is formed in a cross shape in a horizontal direction and a vertical direction. The bushing according to the first or second aspect of the invention, wherein the center of the terminal connecting portion of the center conductor is provided with a communication port that communicates from the vent port to the inner side of the tubular portion. The bushing according to the first or second aspect of the invention, wherein the mounting portion of the insulating cylinder is provided with a vent slit that penetrates in a direction of the axis.