Patent Description:
A gas insulated switchgear includes a switch for interrupting current. The switch includes a movable-side terminal having a movable electrode, a fixed-side terminal provided so as to be opposed to the movable-side terminal, and a driving portion for linearly driving the movable electrode toward the fixed-side terminal. The fixed-side terminal has a fixed electrode, a latch portion for engaging the fixed electrode with the movable electrode, and an opening mechanism for separating the fixed electrode from the movable electrode. The opening mechanism has an opening spring for driving the fixed electrode in a direction to separate from the movable electrode.

At the time of closing the switch, the driving portion drives the movable electrode in a direction to approach the fixed electrode, so as to engage the movable electrode and the fixed electrode with each other. At the time of opening the switch, the driving portion drives the movable electrode in a direction away from the fixed electrode. At this time, the fixed electrode is pulled together with the movable electrode, whereby the opening spring of the opening mechanism is contracted. When the fixed electrode is pulled to a predetermined position, engagement of the latch portion is released by a restoring force of the opening spring. Thus, the fixed electrode is separated from the movable electrode, whereby the switch is opened.

A conventional latch portion of a switch has a plate spring structure of which one end is fixed and another end has a claw portion (see, for example, Patent Document <NUM>).

In the conventional latch portion, the claw portion needs to have both a function of keeping engagement between the movable electrode and the fixed electrode against a spring load of the opening spring, and a function of releasing the engagement in accordance with the position of the fixed electrode. Therefore, because of axial misalignment between the movable electrode and the fixed electrode, change in a frictional force at the claw portion and a part engaged with the claw portion, and the like, the position where the fixed electrode is separated from the movable electrode is not stabilized, and since an engagement retaining force is weak, an opening spring having a great spring load cannot be applied, and thus the interruption speed cannot be increased.

The present disclosure has been made to solve the above problem, and an object of the present disclosure is to provide a gas insulated switchgear having a switch that enables adjustment of the interruption speed while stabilizing the position where the fixed electrode is separated from the movable electrode.

A gas insulated switchgear according to the present disclosure includes: a movable electrode; a fixed electrode provided on a same axis as the movable electrode; a driving portion which linearly drives the movable electrode in a direction of the axis so that the movable electrode contacts with/separates from the fixed electrode; and an opening mechanism which separates the fixed electrode from the movable electrode. The movable electrode has a taper portion having a recessed surface toward the axis, at a part to contact with the fixed electrode, and has a protrusion protruding toward the axis, at an outer circumferential part of the taper portion. The fixed electrode includes a latch portion composed of a claw having an engagement portion to be engaged with the protrusion and a slope portion to contact with the taper portion, and a contact-pressure spring applying a restoring force to the claw in a direction crossing the axis.

In the gas insulated switchgear according to the present disclosure, the fixed electrode includes the latch portion composed of the claw having the engagement portion to be engaged with the protrusion and the slope portion to contact with the taper portion, and the contact-pressure spring applying the restoring force to the claw in the direction crossing the axis. Thus, it is possible to adjust the interruption speed while stabilizing the position where the fixed electrode is separated from the movable electrode.

Hereinafter, a gas insulated switchgear according to embodiments for carrying out the present disclosure will be described in detail with reference to the drawings. In the drawings, the same reference characters denote the same or corresponding parts.

<FIG> is a sectional view of a switch of a gas insulated switchgear according to embodiment <NUM>. A switch <NUM> of the gas insulated switchgear shown in <FIG> is in an opened state. The switch <NUM> includes a flange <NUM>, a fixed-side terminal <NUM> fixed to an insulation holder <NUM>, and a movable-side terminal <NUM>. A cylindrical movable electrode rod <NUM> having a threaded inner circumferential surface and a columnar movable-side shaft rod <NUM> for linearly driving the movable electrode rod <NUM>, are provided inside the movable-side terminal <NUM>. The movable electrode rod <NUM> and the movable-side shaft rod <NUM> are provided on the same axis, and the movable electrode rod <NUM> and the movable-side shaft rod <NUM> compose a movable electrode <NUM>. The outer circumferential surface of the movable-side shaft rod <NUM> is threaded for linearly driving the movable electrode rod <NUM>. An insulation rod <NUM> is connected to one end of the movable-side shaft rod <NUM>. The insulation rod <NUM> is connected to a driving portion <NUM>. A conductive spring component (not shown) is provided between the movable-side terminal <NUM> and the movable electrode rod <NUM>. Hereinafter, the longitudinal direction of the movable electrode rod <NUM> and the movable-side shaft rod <NUM> provided on the same axis is referred to as an axial direction.

The fixed-side terminal <NUM> includes a base conductor <NUM>, a cylindrical conductor <NUM> connected to the base conductor, a piston <NUM> provided inside the cylindrical conductor <NUM>, a cylinder <NUM> provided between the cylindrical conductor <NUM> and the piston <NUM>, a fixed electrode <NUM> connected to an end of the cylinder <NUM>, and an opening spring <NUM> provided around the outer circumference of the cylinder <NUM>. The piston <NUM>, the cylinder <NUM>, and the opening spring <NUM> compose an opening mechanism. The fixed electrode <NUM> is provided on the same axis as the movable electrode. An electric field relaxing shield <NUM> is provided at an outer circumferential part of the fixed electrode <NUM>. The electric field relaxing shield <NUM> is drawn out toward the movable-side terminal <NUM> together with the fixed electrode <NUM> when the fixed electrode <NUM> is pulled toward the movable-side terminal <NUM>. An electrode contact-pressure spring <NUM> is provided at an outer circumferential part of the fixed electrode <NUM>, so as to keep contact between the movable electrode rod <NUM> and the fixed electrode <NUM> when the movable electrode rod <NUM> and the fixed electrode <NUM> are conductively in contact with each other.

<FIG> is a sectional view of the fixed electrode <NUM>. <FIG> is a plan view of the fixed electrode <NUM> as seen from A side in <FIG>, and <FIG> is a plan view of the fixed electrode <NUM> as seen from B side in <FIG>. The fixed electrode <NUM> includes a connection rod <NUM> connected to the cylinder <NUM>, a fixed-side shaft rod <NUM>, two claws <NUM> radially formed in directions crossing the axial direction of the fixed-side shaft rod <NUM>, a stopper <NUM> restricting movement of the claws <NUM> in the axial direction and the radial direction, and a contact-pressure spring <NUM> pushing out the claws <NUM> in the outer circumferential direction. The two claws <NUM> are provided at positions opposed to each other with respect to the axis. The two claws <NUM> and the contact-pressure spring <NUM> compose a latch portion <NUM>. The claws <NUM> are pushed out in the outer circumferential direction by the restoring force of the contact-pressure spring <NUM>. The outer periphery of each claw <NUM> has a circular shape, an elliptic shape, a quadrangular shape, or a shape formed by combination thereof. The claw <NUM> has an engagement portion 21a to be engaged with a protrusion formed at the movable electrode rod as described later, and a slope portion 21b to contact with a taper portion formed at the movable-side shaft rod. As shown in <FIG>, the engagement portions 21a of the claws <NUM> have a shape protruding to the outer circumferential side. The slope portions 21b of the claws <NUM> have such a shape that the distal end tapers toward the movable electrode side. The clearance between the fixed-side shaft rod <NUM> and the claws <NUM> in the axial direction, i.e., the horizontal direction in <FIG>, is set to be small so as to suppress wobbling of the latch portion <NUM>.

Next, operation of the switch <NUM> of the gas insulated switchgear in the present embodiment will be described.

When the switch <NUM> in the opened state shown in <FIG> is to be closed, the driving portion <NUM> rotates the insulation rod <NUM>, for example, clockwise. As the insulation rod <NUM> is rotated clockwise, the movable-side shaft rod <NUM> rotates about the axis. As the movable-side shaft rod <NUM> rotates about the axis, the movable electrode rod <NUM> is linearly driven rightward in <FIG> through meshing between the thread on the outer circumferential surface of the movable-side shaft rod <NUM> and the thread on the inner circumferential surface of the movable electrode rod <NUM>.

<FIG> is a sectional view of the switch of the gas insulated switchgear according to the present embodiment, in a closed state. As shown in <FIG>, in the switch <NUM> in a closed state, the distal end of the movable electrode rod <NUM> contacts with the fixed electrode <NUM>. <FIG> is an enlarged sectional view of a specific part of the switch <NUM> in a closed state in the present embodiment. As shown in <FIG>, a taper portion 7a having a recessed surface toward the axis is formed at the distal end of the movable-side shaft rod <NUM>. A protrusion 6a protruding toward the axis is formed on the inner circumferential surface at the distal end of the movable electrode rod <NUM>. In the switch <NUM> in a closed state, the engagement portion 21a of each claw <NUM> is engaged with the protrusion 6a, so that the fixed electrode <NUM> and the movable electrode <NUM> are electrically connected to each other.

When the switch <NUM> is to be opened from the closed state shown in <FIG>, the driving portion <NUM> rotates the insulation rod <NUM> counterclockwise. As the insulation rod <NUM> is rotated counterclockwise, the movable-side shaft rod <NUM> rotates about the axis. As the movable-side shaft rod <NUM> rotates about the axis, the movable electrode rod <NUM> is linearly driven leftward in <FIG> through meshing between the thread on the outer circumferential surface of the movable-side shaft rod <NUM> and the thread on the inner circumferential surface of the movable electrode rod <NUM>.

<FIG> is a sectional view of the switch of the gas insulated switchgear according to the present embodiment, just before the switch is opened. As shown in <FIG>, the fixed electrode <NUM> pulled by the movable electrode rod <NUM> linearly driven leftward enters the inside of the movable-side terminal <NUM>, and the distal end of the fixed electrode <NUM> contacts with the distal end of the movable-side shaft rod <NUM>. <FIG> is an enlarged sectional view of a specific part where the movable-side shaft rod <NUM> and the fixed electrode <NUM> contact with each other. As shown in <FIG>, when the fixed electrode <NUM> enters the inside of the movable-side terminal <NUM>, the slope portion 21b of each claw <NUM> is pressed to the taper portion 7a at the distal end of the movable-side shaft rod <NUM>. At this time, the engagement portion 21a of the claw <NUM> is engaged with the protrusion 6a of the movable electrode rod <NUM>. When the movable electrode rod <NUM> is further linearly driven leftward, the protrusion 6a moves leftward, so that the engagement portion 21a of each claw <NUM> also moves leftward. Along with this, the slope portions 21b of the claws <NUM> are compressed along the taper portions 7a. Thus, the claws <NUM> slide toward the axis while compressing the contact-pressure spring <NUM>.

<FIG> is a sectional view of the switch of the gas insulated switchgear according to the present embodiment, just before the engagement between the engagement portion 21a of each claw <NUM> and the protrusion 6a of the movable electrode rod <NUM> is released. As shown in <FIG>, when the slope portion 21b of each claw <NUM> is compressed along the taper portion 7a, the engagement portion 21a moves toward the inner circumferential side, so that the engagement between the engagement portion 21a and the protrusion 6a of the movable electrode rod <NUM> is released. When the engagement between each engagement portion 21a and the protrusion 6a is released, the fixed electrode <NUM> moves rightward by the restoring force of the opening spring <NUM> that has been compressed, so that the fixed electrode <NUM> is separated from the movable electrode <NUM>. As a result, electric connection between the fixed electrode <NUM> and the movable electrode <NUM> is disconnected, so that the switch <NUM> comes into the opened state shown in <FIG>.

In the gas insulated switchgear of the present embodiment, the latch portion of the switch includes the claw having the engagement portion to be engaged with the protrusion of the movable electrode and the slope portion to contact with the taper portion of the movable electrode rod, and the contact-pressure spring applying the restoring force to the claw in the direction crossing the axis. Thus, the function of keeping engagement between the fixed electrode and the movable electrode against the spring load of the opening spring can be borne by the engagement portion, and the function of releasing the engagement in accordance with the position of the fixed electrode can be borne by the slope portion. As a result, it is possible to stabilize the position where the fixed electrode is separated from the movable electrode, even if axial misalignment between the movable electrode and the fixed electrode, change in the frictional force at the protrusion of the movable electrode, or the like has occurred.

For example, in the latch portion, the force for keeping engagement between the fixed electrode and the movable electrode against the spring load of the opening spring can be adjusted by, for example, the contact angle and the contact area between the engagement portion of the claw and the protrusion of the movable electrode rod. Meanwhile, in the latch portion, the position of the fixed electrode when the engagement is released can be adjusted by, for example, the contact angle and the contact area between the slope portion of the claw and the taper portion of the movable-side shaft rod, and the spring load of the contact-pressure spring. Thus, in the latch portion, the part bearing the function of keeping engagement between the fixed electrode and the movable electrode against the spring load of the opening spring and the part bearing the function of releasing the engagement in accordance with the position of the fixed electrode can be separated from each other, and therefore the respective functions can be adjusted without influencing each other function. Further, since the clearance between the fixed-side shaft rod <NUM> and the claw <NUM> in the axial direction is set to be small, it becomes possible to increase the load of the opening spring. Thus, the opening speed can be increased.

As described above, in the gas insulated switchgear of the present embodiment, the latch portion of the switch includes the claw having the engagement portion to be engaged with the protrusion of the movable electrode and the slope portion to contact with the taper portion of the movable electrode rod, and the contact-pressure spring applying the restoring force to the claw in the direction crossing the axis. Thus, the gas insulated switchgear of the present embodiment makes it possible to adjust the interruption speed while stabilizing the position where the fixed electrode is separated from the movable electrode.

In the present embodiment, the latch portion has two claws. The latch portion may have three or more claws.

<FIG> is a sectional view of a fixed electrode of a switch of a gas insulated switchgear according to embodiment <NUM>. The structure of the switch in the present embodiment is the same as the structure of the switch in embodiment <NUM>. As shown in <FIG>, the fixed electrode <NUM> according to the present embodiment includes two contact-pressure springs <NUM> pushing out the two claws <NUM> in the outer circumferential direction. The two contact-pressure springs <NUM> are respectively provided between the fixed-side shaft rod <NUM> and the two claws <NUM>.

Claim 1:
A gas insulated switchgear comprising:
a movable electrode (<NUM>);
a fixed electrode (<NUM>) provided on a same axis as the movable electrode (<NUM>);
a driving portion (<NUM>) which linearly drives the movable electrode (<NUM>) in a direction of the axis so that the movable electrode (<NUM>) contacts with/separates from the fixed electrode (<NUM>); and
an opening mechanism which separates the fixed electrode (<NUM>) from the movable electrode (<NUM>), characterised in that
the movable electrode (<NUM>) has a taper portion (7a) having a recessed surface toward the direction of the axis, at a part to contact with the fixed electrode (<NUM>), and has a protrusion (6a) protruding toward the direction of the axis, at an outer circumferential part of the taper portion (7a), and
the fixed electrode (<NUM>) includes a latch portion (<NUM>) composed of
a claw (<NUM>) having an engagement portion (21a) to be engaged with the protrusion (6a) and a slope portion (21b) to contact with the taper portion (7a), and
a contact-pressure spring (<NUM>) applying a restoring force to the claw (<NUM>) in a direction crossing the direction of the axis.