JP3440767B2 - Vacuum circuit breaker - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum circuit breaker having a movable rod which rotates about a main shaft as a main point, and has an insulating performance by disposing the main shaft inside a bellows. Is improved. 2. Description of the Related Art In a vacuum valve, a movable rod is moved up and down with respect to a fixed rod by an operation mechanism provided outside the vacuum valve, and an electrode provided at an end of each rod is opened and closed. In a vacuum circuit breaker described in Japanese Patent Application Laid-Open No. 55-143727, a movable rod is rotated about a main shaft as a fulcrum, and a movable electrode installed at an end of the movable rod is opened and closed with a fixed electrode. [0003] However, in a conventional vacuum circuit breaker in which electrodes are opened and closed by rotating a movable rod, a main shaft is provided outside a bellows. In this case, there is a problem that the electric field concentrates on the mounting shaft such as the main shaft and the split pin, and the insulation performance of the device is reduced. An object of the present invention is to provide a vacuum circuit breaker having excellent insulation performance and a reduced size by disposing the main shaft inside the bellows. In order to achieve the above object, in a vacuum circuit breaker according to the present invention, one end of a movable electrode is connected to a fixed electrode and a movable electrode correspondingly arranged in a vacuum valve. And a movable rod extending outside the vacuum valve at the other end, the movable rod rotating about a main shaft to open and close the two electrodes, one end fixedly sealed to the movable rod, and the other end connected to the end of the vacuum valve. In a vacuum circuit breaker having a bellows fixedly sealed to a plate, the main shaft was arranged inside the bellows. An embodiment of the present invention will be described with reference to FIG. [0007] The vacuum valve 1 is constructed as follows, and the inside is vacuum-sealed. The fixing rod 4 is fixed by the sealing fitting 3A provided on the upper part of the insulating cylinder 2. The movable rod 5 extends outside the vacuum valve 1, and includes a bellows 6 and a sealing fitting 3B.
Hold with. At the tips of the fixed rod 4 and the movable rod 5, a fixed electrode 8 and a movable electrode 9 made of, for example, a Cu—Pb alloy are provided, respectively, and the movable rod 5 is bellowed by an operation mechanism (not shown) provided outside the vacuum valve 1. 6 Both electrodes are opened and closed by rotating the main shaft 18 provided outside the fulcrum. The shield 15 is provided to prevent a decrease in withstand voltage of the insulating cylinder 2 due to adhesion of metal vapor released from between the electrodes. The main shaft 18 is arranged inside the bellows 6. The vacuum valve 1 includes a main shaft 18 and a bearing 19 connected to the movable rod 5.
Assemble in a state where it is provided. Alternatively, the vacuum valve 1 may be assembled with the main shaft 18 provided on the movable rod 5 and the bearing 19 may be inserted and attached later from the gap between the bellows 6 and the main shaft 18. It should be noted that the main shaft 18 and the movable rod 5 may be manufactured integrally. The current flow path I is formed by a current collecting structure for applying a contact force to a bearing 19 by a spring 23 as shown in FIG. 2 or a flexible conductor 21 to a movable rod 5 as shown in FIG.
And secure it. Next, the effects of the present invention will be described. In the vacuum circuit breaker of the present invention, since the main shaft 18 is disposed inside the bellows 6, the bellows 6 serves as an electric field shield for the mounting brackets such as the main shaft 18 and the split pins 22, and is compared with the conventional vacuum circuit breaker. The insulation performance is improved. Therefore, the distance between phases can be reduced, and a compact vacuum circuit breaker can be provided. In addition, since the metallic foreign matter generated in the main shaft 18 and the bearing 19 can be captured in the bellows 6, the insulation performance of the device is improved. In addition, by assembling the vacuum valve 1 with the main shaft 18 and the bearing 19 mounted on the movable rod 5, the following effects can be obtained. As shown in FIG.
In the conventional assembling method, since the main shaft 18 is attached after the vacuum valve 1 is assembled, a gap between the bearing 19 and the bellows 6 needs to be equal to or longer than the length L of the main shaft 18, and there is a problem that the bellows 6 becomes large. However, in the present invention, the bellows 6 is
8, the bearing 19, and the movable rod 5 can be stored in a size that can be significantly reduced as compared with the related art. FIG.
Even when the bearing 19 is attached after the vacuum valve 1 is assembled as described above, the clearance between the bearing 19 and the bellows 6 only needs to be as large as the bearing 19 can be inserted, and the bellows 6 can be downsized as compared with the conventional method. Further, when the vacuum valve 1 is assembled with the bearing 19 attached, the bearing 19 can receive a vacuum suction force F acting on the movable rod 5 and the bellows 6.
Vacuum sealing can be performed without damaging the bellows 6. Conventionally, vacuum sealing was performed in a state where a member for receiving a vacuum suction force F was separately provided. However, in the present invention, the above member is unnecessary because the bearing 19 also serves as the member. The present invention has the effect of reducing the stress acting on the bellows 6 and improving the life. As shown in FIG. 6, when the main shaft 18 exists outside the bellows 6 as in a conventional vacuum circuit breaker, the bellows 6 becomes a combined operation of “axis shift operation” and “square bending operation”. Shrinkage coexists. At this time, stress concentration occurs in the bellows end portion S1, and depending on conditions such as the rotation angle, there is a portion S2 where the peaks contact each other, which promotes stress concentration.
Further, since the stress does not act on the central part of the bellows due to the coexistence of the elongation and the contraction, the absolute length of the bellows is required to reduce the stress, and as a result, there is a drawback that the apparatus becomes large. However, in the present invention, as shown in FIG. 7, the bellows 6 performs a pure “square bending operation”, and the bellows 6 performs one of the operations without any coexistence of expansion and contraction on one side. (6) The stress is remarkably reduced as compared with the case where it exists outside. Further, as can be seen from the operation of the bellows 6 shown in FIGS. 6 and 7, in the conventional method of using the bellows 6, there is a portion where the curvature locally changes, and the stress based on the pressure difference between the atmosphere and the vacuum is generated. Is big. On the other hand, in the present invention, since the bellows 6 is deformed almost uniformly, the influence of the pressure difference is small, and the life of the bellows 6 is further improved. As described above, according to the vacuum circuit breaker of the present invention, since the main shaft of the movable rod is disposed inside the bellows, it is possible to avoid the electric field concentration on the mounting shaft such as the main shaft and the split pin. As a result, the insulation performance is improved, and as a result, a compact vacuum circuit breaker can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of a vacuum valve according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a bearing portion of the vacuum circuit breaker according to the embodiment of the present invention. FIG. 3 is a side sectional view of a vacuum circuit breaker according to another embodiment of the present invention. FIG. 4 is an explanatory view of a bearing portion in a conventional vacuum circuit breaker assembling method. FIG. 5 is an explanatory diagram of a bearing unit according to the embodiment of the present invention. FIG. 6 is a side sectional view illustrating an operation of a bellows in a conventional vacuum circuit breaker. FIG. 7 is a side sectional view for explaining the operation of the bellows in the embodiment of the present invention. [Description of Signs] 1 ... Vacuum valve, 3 ... End plate, 4 ... Fixed rod, 5 ... Movable rod, 6 ... Bellows, 8 ... Fixed electrode, 9 ... Movable electrode,
18 ... spindle, 19 ... bearing, 21 ... flexible conductor, 2
2 ... split pin, S (S1, S2) ... part.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 33/66

Claims (1)

(57) [Claim 1] A fixed electrode and a movable electrode correspondingly arranged in a vacuum valve, and a movable rod having one end connected to the movable electrode and the other end extending out of the vacuum valve. The movable rod rotates around a main shaft to open and close the two electrodes, a vacuum circuit breaker having a bellows having one end fixedly sealed to the movable rod and the other end fixedly sealed to an end plate of a vacuum valve. A vacuum circuit breaker, wherein the main shaft is disposed inside the bellows.