Patent Description:
There is known a switch having a quick-acting mechanism (quick-trip mechanism) as an arc extinguishing structure in order to improve the current interruption performance of the switch. The quick-acting mechanism is such a feature that, at the time of opening contacts, the contact opening speed is increased and an arc is elongated to a length needed for arc extinction within a time not causing contact damage, thus improving the interruption performance.

The applicant has proposed a switch having a structure in which a quick-acting mechanism is not provided in a limited space on the movable electrode rod side (see, for example, Patent Document <NUM>). The switch disclosed in Patent Document <NUM> operates such that, at the time of closing, a movable electrode rod provided inside a movable-side terminal provided so as to be opposed to a fixed-side terminal is moved to ensure conduction between the fixed-side terminal and the movable-side terminal, and at the time of opening, current between the fixed-side terminal and the movable electrode rod is interrupted by the quick-acting mechanism provided at the fixed-side terminal.

Patent Document <NUM>, according to its abstract, states that, to provide a switch capable of installing a quick-acting mechanism for current cutoff irrelevantly to an installation space of a movable electrode rod, and capable of stably cutting off current between a fixed side terminal and a movable side terminal, in the switch, when carrying out closing, continuity between the fixed side terminal and the movable side terminal is secured by moving the movable electrode rod housed in the movable side terminal disposed facing the fixed side terminal, and when carrying out opening, the current between the fixed side terminal and the movable electrode rod is cut off by the quick-acting mechanism provided in the fixed side terminal.

The quick-acting mechanism described in Patent Document <NUM> includes a shaft rod electrically connected to the fixed-side terminal, a contact for receiving an arc generated at the time of opening at an end of the shaft rod, an engagement portion for engaging the shaft rod and the movable electrode rod with each other, and a spring for driving the shaft rod in a direction opposite to the movable-side terminal. Then, at the time of closing between the fixed-side terminal and the movable-side terminal, the movable electrode rod and the shaft rod are engaged with each other, and at the time of opening, the spring is released at a predetermined position, thereby separating the movable electrode rod and the shaft rod from each other and interrupting current. Therefore, by the spring being released at the time of opening, after the movable electrode rod and the shaft rod are separated, an impact force occurs when a movable contact comes into contact with the fixed-side terminal. Conventionally, the movable-side terminal and the fixed-side terminal are supported in a cantilever manner, and great loads occur in directions of support portions of the fixed-side terminal and the movable-side terminal by the impact force occurring at the time of opening/closing. Thus, there have been such constraints that interruption current to an extent that can withstand the impact force needs to be addressed or increase in the speed of the quick-acting mechanism is limited because the impact force increases.

The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide a switch having a stable current interruption function while dispersing an impact force occurring at the time of interrupting current.

According to the present disclosure, a switch as defined in independent claim <NUM> is provided. Further embodiments of the claimed invention are defined in the dependent claims. Although the claimed invention is only defined by the claims, the below embodiments, examples, and aspects are present for aiding in understanding the background and advantages of the claimed invention.

In the switch according to the present disclosure, the fixed-side terminal is supported from a plurality of directions that are symmetric with respect to the axial direction, whereby an impact force occurring at the time of interrupting current (at the time of closing) is dispersed, thus obtaining a stable current interruption function.

In the drawings, the same reference characters denote the same or corresponding parts.

A switch according to each embodiment is used for a gas-insulated switchgear installed at a power reception point of a general consumer or a substation of an electric power company, for example.

Hereinafter, a switch according to embodiment <NUM> will be described with reference to the drawings.

<FIG> is a specific part sectional view showing the structure of the switch according to embodiment <NUM>. In <FIG>, the switch <NUM> is in an opened state. In the switch <NUM>, upper parts of a movable-side terminal <NUM> and a fixed-side terminal <NUM> are supported by a first insulation support portion <NUM> having an end fixed to a flange <NUM>, and the movable-side terminal <NUM> and the fixed-side terminal <NUM> are arranged so as to be opposed to each other. A lower part of the movable-side terminal <NUM> is supported by a support conductor <NUM> on the movable side connected to the flange <NUM>. At a lower part of the fixed-side terminal <NUM>, a coupling portion <NUM> is provided for coupling with a second insulation support portion <NUM>, and the second insulation support portion <NUM> fixed to the support conductor <NUM> supports the fixed-side terminal <NUM> by being coupled via the coupling portion <NUM>. The support conductor <NUM> is connected to and supported by a bushing <NUM> fixed to the flange <NUM> and having a conductor at the center and an insulating material surrounding the conductor. The coupling portion <NUM> has therein counterbores in two directions perpendicular to each other. The fixed-side terminal <NUM> and the coupling portion <NUM> are connected by the counterbore on one side, and the second insulation support portion <NUM> and the coupling portion <NUM> are connected by the counterbore on the other side perpendicular thereto. Bolts used for the connections protrude from the coupling portion <NUM>, thus suppressing occurrence of electric field concentration.

The outer shape of the fixed-side terminal <NUM> is a cylindrical shape. On the movable-side terminal <NUM> side, a shaft rod <NUM> of a movable contact <NUM> is provided along the axis of the cylinder, and a spring <NUM> is provided around the shaft rod <NUM>.

In the movable-side terminal <NUM>, the movable electrode rod <NUM> is provided coaxially with the shaft rod <NUM> of the fixed-side terminal <NUM>. The switch <NUM> is closed by engaging one end of the movable electrode rod <NUM> with the movable contact <NUM>, and the switch <NUM> is opened by releasing engagement between the movable electrode rod <NUM> and the movable contact <NUM>. Another end of the movable electrode rod <NUM> is connected to a movable shaft <NUM>, and the movable shaft <NUM> is connected to an operation mechanism portion <NUM> outside the flange <NUM> via, for example, bellows. The movable shaft <NUM>, the movable electrode rod <NUM>, and the shaft rod <NUM> are coaxial with each other.

Next, a quick-acting mechanism having a current interruption function in the switch <NUM> will be described. <FIG> is a partial enlarged view of the fixed-side terminal <NUM> and shows the structure of the movable contact <NUM>. As described above, the movable contact <NUM> includes the shaft rod <NUM> and the spring <NUM> provided therearound. As described below, at the time of closing, one end of the movable electrode rod <NUM> is engaged with the movable contact <NUM> and thus is electrically connected to the shaft rod <NUM>. The shaft rod <NUM> is positioned by a stationary end <NUM> at the time of opening. <FIG> shows a closed state of the switch <NUM>. <FIG> shows shifting from the closed state in <FIG> to the opened state in <FIG>, i.e., an opening operation.

In <FIG>, at the time of closing, the movable electrode rod <NUM> moves toward the fixed-side terminal <NUM> via the movable shaft <NUM> by the operation mechanism portion <NUM>. Then, the movable electrode rod <NUM> is inserted into the fixed-side terminal <NUM>, to push the spring <NUM> and engage with the movable contact <NUM>, so that the movable-side terminal <NUM> and the fixed-side terminal <NUM> become electrically conductive to each other.

In <FIG>, when the switch <NUM> starts an opening operation, the movable electrode rod <NUM> moves toward the movable-side terminal <NUM> side by the operation mechanism portion <NUM>, and the shaft rod <NUM> of the movable contact <NUM> moves toward the movable-side terminal <NUM> side while engaging with the movable electrode rod <NUM>, so that the spring <NUM> composing the movable contact <NUM> is energized so as to extend. When the movable electrode rod <NUM> or the shaft rod <NUM> reaches a predetermined position, engagement of the movable contact <NUM> and the movable electrode rod <NUM> is released, so that the spring <NUM> is released. The movable contact <NUM> is stored into the fixed-side terminal <NUM> and the movable electrode rod <NUM> is stored into the movable-side terminal <NUM>, whereby the opening operation is completed, thus coming into the opened state in <FIG>.

During the opening operation to shift from the state in <FIG> to the state in <FIG>, when the spring <NUM> is released, the movable contact <NUM> moves into the fixed-side terminal <NUM> and the shaft rod <NUM> comes into contact with the stationary end <NUM>, so that an impact force occurs. The switch needs to have a structure for withstanding the impact force. <FIG> shows a comparative example of embodiment <NUM>, and is different from <FIG> in that the second insulation support portion <NUM> is not provided and the fixed-side terminal <NUM> is not supported from below. In the structure as shown in <FIG>, at the time of opening, the movable contact <NUM> is stored into the fixed-side terminal <NUM> and the shaft rod <NUM> comes into contact with the stationary end <NUM>, so that an impact force occurs. At this time, a load acts on the fixed-side terminal <NUM> in the horizontal direction. Since the fixed-side terminal <NUM> is supported with a cantilever structure by the first insulation support portion <NUM>, a load acts on the first insulation support portion <NUM> upward as shown by an arrow in <FIG>. In this structure, for improving the current interruption performance, it is conceivable that the load of the spring <NUM> is increased to increase the opening/closing speed. However, increase in the impact force depending on the stored energy of the spring <NUM> might cause deformation or breakage of the first insulation support portion <NUM>.

In embodiment <NUM>, as shown in <FIG>, <FIG>, and <FIG>, the upper part of the fixed-side terminal <NUM> is supported by the first insulation support portion <NUM>, and the lower part of the fixed-side terminal <NUM> located at a symmetric position with respect to the movable shaft <NUM> is supported by the second insulation support portion <NUM>. The first insulation support portion <NUM> and the second insulation support portion <NUM> support the fixed-side terminal <NUM> so as to be parallel and symmetric with respect to the movable shaft <NUM>. That is, the first insulation support portion <NUM> and the second insulation support portion <NUM> are provided such that, in <FIG>, a distance L1 between the movable shaft <NUM> and the first insulation support portion <NUM>, and a distance L2 between the movable shaft <NUM> and the second insulation support portion <NUM>, are almost equal to each other.

In embodiment <NUM>, the structure of the switch for one phase is shown in <FIG>, <FIG>, and <FIG>. However, in a switch for three phases, three of such devices are arranged in the horizontal direction. That is, the switch is configured such that three devices are arranged in the depth direction in the drawings. In this case, the first insulation support portions <NUM> and the second insulation support portions supporting the fixed-side terminals <NUM> are arranged on the upper and lower sides, whereby the distances between the devices for three phases can be reduced.

Desirably, the first insulation support portion <NUM> and the second insulation support portion <NUM> are formed by using, for example, epoxy resin, etc., and are adjusted such that the elastic deformation amounts of the first insulation support portion <NUM> and the second insulation support portion <NUM> become equivalent to each other when an opening/closing impact occurs, thus forming such a structure that a load does not act unevenly on only one of the first insulation support portion <NUM> and the second insulation support portion <NUM>. With this structure, propagation of an impact force to the flange <NUM> supporting the switch <NUM> can be suppressed. Thus, without increasing the strength of the flange <NUM>, it becomes possible to increase the opening/closing speed so as to improve the current interruption performance.

As described above, in the switch <NUM> according to embodiment <NUM>, the fixed-side terminal <NUM> is supported by the first insulation support portion <NUM> and the second insulation support portion <NUM> at symmetric positions with respect to the movable shaft <NUM>, and the first insulation support portion <NUM> and the second insulation support portion <NUM> are parallel with the movable shaft <NUM> and each have an end fixed by the flange <NUM>. Thus, an impact force in an opening/closing operation of the switch <NUM> can be dispersed by the first insulation support portion <NUM> and the second insulation support portion <NUM>, whereby it becomes possible to provide a switch having a stable current interruption function.

In addition, the fixed-side terminal <NUM> is supported by the first insulation support portion <NUM> and the second insulation support portion <NUM> and thus a load is dispersed therebetween, whereby the mechanical strengths of the first insulation support portion <NUM>, the second insulation support portion <NUM>, and the operation mechanism portion <NUM> can be designed to be lower than in conventional art. As a result, the switch can be downsized, thus leading to reduction in the installation space of the switch and cost reduction of the switch.

Hereinafter, a switch according to embodiment <NUM> will be described with reference to <FIG>.

<FIG> is a specific part sectional view showing the structure of the switch according to embodiment <NUM>. In <FIG>, the switch <NUM> is in an opened state. Difference from <FIG> is that a lower part of the fixed-side terminal <NUM> is supported by a second insulation support portion <NUM> directly fixed to the flange <NUM>. The other structures are the same as those in embodiment <NUM> and therefore description thereof is omitted.

In <FIG>, the second insulation support portion <NUM> is directly fixed to the flange <NUM>, and the support conductor <NUM> on the movable side is fixed to the flange <NUM> independently of the second insulation support portion <NUM>. As in embodiment <NUM>, the second insulation support portion <NUM> and the first insulation support portion <NUM> are arranged at symmetric positions with respect to the movable shaft <NUM> and in parallel with the movable shaft <NUM> such that the distance L1 between the movable shaft <NUM> and the first insulation support portion <NUM>, and the distance L2 between the movable shaft <NUM> and the second insulation support portion <NUM>, are almost equal to each other. In addition, the second insulation support portion <NUM> and the first insulation support portion <NUM> are adjusted such that their elastic deformation amounts become equivalent to each other. Thus, since the lower part of the fixed-side terminal <NUM> is directly supported by the second insulation support portion <NUM>, the coupling portion <NUM> need not be provided as in embodiment <NUM>, so that the number of components can be decreased. The movable-side terminal <NUM> is supported by the first insulation support portion <NUM> and the support conductor <NUM> fixed to the flange <NUM>.

As described above, according to embodiment <NUM>, the same effects as those in embodiment <NUM> are provided, and in addition, it is possible to obtain a switch having such a structure that the fixed-side terminal <NUM> is supported from two directions and loads acting on the first insulation support portion <NUM> and the second insulation support portion <NUM> are dispersed, with a decreased number of components.

The above embodiments <NUM> and <NUM> have shown the examples in which the fixed-side terminal <NUM> is supported by the insulation support portions from the upper and lower parts as symmetric positions with respect to the movable shaft <NUM>. However, as long as designing can be made such that a load at the time of opening/closing is equivalently dispersed between two support members supporting the fixed-side terminal <NUM>, the support positions are not limited to the upper and lower parts. The support positions may be symmetric positions at an angle shifted from the vertical direction, or may be positions in the horizontal direction with respect to the movable shaft <NUM>.

The above embodiments <NUM> and <NUM> have shown the examples in which the fixed-side terminal <NUM> is supported by the insulation support portions from the upper and lower parts as symmetric positions with respect to the movable shaft <NUM>. However, the number of the insulation support portions is not limited to two. The insulation support portions may be arranged at equal distances from the movable shaft <NUM> and at equiangular positions around the movable shaft <NUM> so that a load can be dispersed.

Claim 1:
A switch (<NUM>) comprising:
a fixed-side terminal (<NUM>) having a movable contact (<NUM>); and
a movable-side terminal (<NUM>) which is provided so as to be opposed to the fixed-side terminal (<NUM>) and includes a movable electrode rod (<NUM>) which ensures electric conduction to the fixed-side terminal (<NUM>) and is contactable therewith/separable therefrom, wherein
the movable-side terminal (<NUM>) is fixed on a side opposite to a side where the movable-side terminal (<NUM>) is opposed to the fixed-side terminal (<NUM>),
the movable contact (<NUM>) has a shaft rod (<NUM>) movable coaxially with the movable electrode rod (<NUM>), and a spring (<NUM>) biasing the shaft rod (<NUM>),
at a time of closing between the fixed-side terminal (<NUM>) and the movable-side terminal (<NUM>), an end of the movable electrode rod (<NUM>) is engaged with the movable contact (<NUM>), and
at a time of opening between the fixed-side terminal (<NUM>) and the movable-side terminal (<NUM>), in a state in which the movable electrode rod (<NUM>) is engaged with the movable contact (<NUM>), the movable electrode rod (<NUM>) moves toward the movable-side terminal (<NUM>), so that the spring (<NUM>) is energized, and when the movable electrode rod (<NUM>) reaches a predetermined position, the spring (<NUM>) is released, so that the shaft rod (<NUM>) moves toward the fixed-side terminal (<NUM>), thus separating the movable contact (<NUM>) from the movable electrode rod (<NUM>), characterized in that
the fixed-side terminal (<NUM>) is supported by a plurality of insulation support portions (<NUM>, <NUM>, <NUM>) provided at symmetric positions with respect to an axis on which the movable electrode rod (<NUM>) moves, an end of each insulation support portion (<NUM>, <NUM>, <NUM>) being fixed.