The present invention relates to a switch including a fixed contact and a movable contact.
A gas-insulated switching apparatus includes switches that each connect and disconnect a circuit by causing a movable contact and a fixed contact to make contact and separate with each other. Such switches include a grounding switch used for grounding a main circuit in equipment inspection. As disclosed in Patent Literature 1, a movable contact on the grounding side is moved so as to come into contact with a fixed contact on the main circuit side to ground the main circuit. Before the movable contact is placed into contact with the fixed contact, the main circuit is supposed to be disconnected so that no voltage is applied to the fixed contact.
Patent Literature 1: Japanese Patent Application Laid-open No. 2009-163946
Such switches are in some cases required to accomplish a duty to provide the capability to be turned on safely even when the movable contact is inadvertently brought into contact with the fixed contact while the main circuit is not disconnected and remaining closed. To accomplish this duty, it is necessary to reduce the duration of arc formation between the movable contact and the fixed contact. As a solution, an operation speed of the movable contact has been increased so as to reduce the time from arc formation until the movable contact comes into contact with the fixed contact. For enabling the movable contact to operate quickly, increase in size and cost of an operation device thus causes a problem.
The present invention has been achieved in view of the above, and an object of the present invention is to provide a switch that reduces the duration of arc formation and lowers an operation speed of a movable contact, thereby enabling reduction in size and cost of an operation device.
A switch according to an aspect of the present invention includes: a first contact placed so as to be capable of reciprocating in a first direction along an operation axis and in a second direction opposite the first direction; and a second contact placed on a side of the first direction of the first contact so as to be capable of reciprocating in the first direction along the operation axis and in the second direction. When the first direction is a direction from the first contact toward the second contact and the second direction is a direction opposite the first direction, the switch includes an urging part that urges the second contact in the second direction; an engaging part placed integrally with the second contact on the first direction side; and a conductor part placed away from the engaging portion in a direction perpendicular to the operation axis and electrically connected to the second contact. The switch also includes: a first magnetic material part surrounding the conductor part and made of a magnetic material; and a second magnetic material part placed between the first magnetic material part and the engaging part and made of a magnetic material. The second magnetic material part is placed at a position that causes, when no current flows through the conductor part, the second magnetic material part to engage with the engaging part to restrict the second contact from moving in the second direction due to the urging force. A space is provided between the second magnetic material part and the first magnetic material part to allow the second magnetic material part to move to a side of the first magnetic material part. The second magnetic material part moves to the side of the first magnetic material part so as to disengage from the engaging part.
A switch according to the present invention lowers an operation speed of a movable contact, thereby enabling reduction in size of an operation device and increase in flexibility in design of the operation device.
Exemplary embodiments of a switch according to the present invention is described below in detail with reference to the drawings. The present invention is not limited to the embodiments.
The movable contact 2 and the arc contact 3 are placed on an identical operation axis 50 and face each other. In the disclosure below, a direction that is parallel with the operation axis 50 and directed from the movable contact 2 toward the arc contact 3 is a first direction and indicated by an arrow X in the drawings. A direction that is parallel with the operation axis 50 and directed from the arc contact 3 toward the movable contact 2 is a second direction and indicated by an arrow Y in the drawings.
The movable contact 2 is placed along the operation axis 50 and configured to reciprocate. The movable contact 2 is a conductor having a cylindrical shape, and the operation axis 50 serves as a central axis of the movable contact 2. As described below in detail, when the movable contact 2 moves in the direction indicated by the arrow X, an end portion 2a of the movable contact 2 located toward the direction indicated by the arrow X comes into contact with the arc contact 3, and a side face 2b of the movable contact 2 comes into contact with the fixed contact 4.
The arc contact 3 is retained by a guide part 7 that is made by using a conductor; the arc contact 3 is configured to reciprocate along the operation axis 50. A sliding contact 16 that is placed on the guide part 7 maintains electric connection between the arc contact 3 and the guide part 7. The arc contact 3 is a conductor having a cylindrical shape and centered on the operation axis 50. The arc contact 3 has an end portion 3a that is toward the direction indicated by the arrow Y and that is made of an arc resistant material. The guide part 7 surrounds the arc contact 3. The arc contact 3 is urged toward the direction indicated by the arrow Y by an urging part 15. The urging part 15 is, for example, a compression spring placed between the arc contact 3 and the guide part 7.
The shield 5 is made of a conductor and accommodates the arc contact 3, the fixed contact 4, and the guide part 7. In a wall surface of the shield 5 located toward the direction indicated by the arrow Y, the first opening 5a is provided in an area that includes a portion of the shield 5 that intersects with the operation axis 50. The first opening 5a covers a periphery of the end portion 3a of the arc contact 3 in a state illustrated in
A second opening 5b is formed in a wall surface of the shield 5 located toward the direction indicated by the arrow X. The wall surface of the shield 5 located toward the direction indicated by the arrow X is in contact with the guide part 7.
The engaging part 8 is made using an insulator. The engaging part 8 is integrated with the arc contact 3 and placed toward the direction indicated by the arrow X with respect to the arc contact 3. The engaging part 8 passes through the second opening 5b, which is formed in the shield 5, and a part of the engaging part 8 is located outside the shield 5.
The engaging mechanism 6 is placed outside the shield 5 away from the engaging part 8 in a direction perpendicular to the operation axis 50. The engaging mechanism 6 may be illustrated with hatching omitted to facilitate understanding.
The conductor part 9 is made of a conductor and placed away from the engaging part 8 in the direction perpendicular to the operation axis 50. The conductor part 9 is in contact with the shield 5 and electrically connected to the shield 5.
The attracting part 10 is made of a magnetic material. As illustrated in
The part to be attracted 11 is made of a magnetic material. The part to be attracted 11 is placed between the engaging part 8 and the conductor part 9. In the first embodiment, the part to be attracted 11 is supported on the attracting part 10 by a pivot portion 11a that is placed on an end of the part to be attracted 11 located toward the direction indicated by the arrow X. The part to be attracted 11 is pivotable about the pivot portion 11a. The part to be attracted 11 is urged in a direction in which an edge portion 11b of the part to be attracted 11 located toward the arrow Y moves to the side of the engaging part 8. The urging force is given by, for example, a torsion spring placed at the pivot portion 11a.
A space is provided between the part to be attracted 11 and the attracting part 10 so as to allow the edge portion 11b of the part to be attracted 11 to move to a side of the attracting part 10. An engagement portion 11c that engages with the engaging portion 8 to restrict the engaging portion 8 from moving in the direction indicated by the arrow Y is formed on the edge portion 11b of the part to be attracted 11. In other words, the part to be attracted 11 restricts the arc contact 3, which is formed integrally with the engaging part 8, from moving in the direction indicated by the arrow Y due to the urging force of the urging part 15.
An operation of the part to be attracted 11 performed when current flows through the conductor part 9 is described below.
An operation of the switch 1 according to the first embodiment from when the movable contact 2 is moved in the direction indicated by the arrow X from a state illustrated in
As illustrated in
When the arc 12 is formed between the movable contact 2 and the arc contact 3, current flows through a path 13 illustrated in
When the arc 12 is formed between the movable contact 2 and the shield 5, current flows through a path 14 illustrated in
In other words, current flows through the conductor part 9 and the arc contact 3 is allowed to move in the direction indicated by the arrow Y in both of the cases when the arc 12 is formed between the movable contact 2 and the arc contact 3 and when the arc 12 is formed between the movable contact 2 and the shield 5.
As illustrated in
After the end portion 2a of the movable contact 2 and the end portion 3a of the arc contact 3 come into contact with each other, when the movable contact 2 further moves in the direction indicated by the arrow X, and the arc contact 3 is pushed in the direction indicated by the arrow X against the urging force of the urging part 15 as illustrated in
After the grounding is completed, the part to be attracted 11 returns to a position away from the attracting part 10 when the current stops flowing through the conductor part 9. When the movable contact 2 is moved in the direction indicated by the arrow Y from the state illustrated in
In the switch 1 described above, formation of the arc 12 between the arc contact 3 and the movable contact 2 or between the shield 5 and the movable contact 2 causes the arc contact 3 to move toward the movable contact 2, thereby enabling the movable contact 2 and the arc contact 3 to approach each other after the formation of the arc 12 at a relative velocity resulting from a moving speed of the movable contact 2 and a moving speed of the arc contact 3 added together.
To prevent damage to the movable contact 2 and the arc contact 3 due to the arc 12, the duration of the arc 12 formation is desirably reduced. When the duration of the arc 12 formation required to prevent damage to the movable contact 2 and the arc contact 3 is the same, the switch 1 according to the first embodiment, in which the arc contact 3 is moved toward the movable contact 2, can lower the moving speed of the movable contact 2 in comparison with a configuration in which only the movable contact 2 is moved. That is, the first embodiment can reduce the duration of arc formation and lower the moving speed of the movable contact 2.
The switch 1 according to the first embodiment can lower the moving speed of the movable contact 2 as described above, thus enabling reduction in size and cost of an undepicted operation device for operating the movable contact and also reduction in size and cost of the switch 1, which includes the operation device.
A configuration that exerts the urging force to move the part to be attracted 11 away from the attracting part 10 when current stops flowing through the conductor part 9 in the engaging mechanism 6, is not limited to a torsion spring. For example, the attracting part 10 and the part to be attracted 11 may be integrally formed. In this case, the part to be attracted 11 deforms when attracted by the attracting part 10, and a restoring force due to an elastic force of the part to be attracted 11 acts as the urging force when the part to be attracted 11 moves away from the attracting part 10. The engaging mechanism 6 may have any configuration as long as it can produce a force to move the part to be attracted 11 away from the attracting part 10 as described above. The switch 1 may be used as a disconnect switch other than a grounding switch.
The movable-side main contact 54 moves together with the movable contact 2. When the movable-side main contact 54 moves in the direction indicated by the arrow X, the guide part 7 is allowed to be inserted into a space inside the contact portions 54a and a side face 7a of the guide part 7 comes into contact with the contact portions 54a. In other words, in the switch 51 according to the second embodiment, the contact portions 54a serve as the main contact on the movable side, and the guide part 7 is a fourth contact that serves as the main contact on the fixed side.
The first opening 5a, which is formed in the shield 5, is formed so as to have a size that allows movable-side main contact 54 to pass therethrough.
An operation of the switch 51 according to the second embodiment from when the movable contact 2 is moved in the direction indicated by the arrow X from a state illustrated in
As illustrated in
When the arc 12 is formed between the movable contact 2 and the arc contact 3, current flows through a path 55 illustrated in
When the arc 12 is formed between the movable-side main contact 54 and the shield 5, current flows through a path 56 illustrated in
In other words, current flows through the conductor part 9 and the arc contact 3 is allowed to move in the direction indicated by the arrow Y in both of the cases when the arc 12 is formed between the movable contact 2 and the arc contact 3 and when the arc 12 is formed between the movable-side main contact 54 and the shield 5.
As illustrated in
After the end portion 2a of the movable contact 2 and the end portion 3a of the arc contact 3 come into contact with each other, the movable contact 2 further moves in the direction indicated by the arrow X, the arc contact 3 is pushed in the direction indicated by the arrow X against the urging force of the urging part 15 as illustrated in
After the grounding is completed, the part to be attracted 11 returns to a position away from the attracting part 10 when the current stops flowing through the conductor part 9. When the movable contact 2 is moved in the direction indicated by the arrow Y from the state illustrated in
In the switch 51 described above, formation of the arc 12 causes the arc contact 3 to move toward the movable contact 2, thereby enabling the movable contact 2 and the arc contact 3 to approach each other after the formation of the arc 12 at a relative velocity resulting from a moving speed of the movable contact 2 and a moving speed of the arc contact 3 added together. The second embodiment thus can reduce the duration of arc formation and lower the moving speed of the movable contact 2, as in the case with the first embodiment. The second embodiment can also reduce the size and cost of an undepicted operation device for operating the movable contact 2 and reduce the size and cost of the switch 51, which includes the operation device.
The configurations in the embodiments described above represent some examples of the present invention, and they can be combined with another publicly known technique and partially omitted or modified without departing from the spirit of the present invention.
1 switch; 2 movable contact (first contact); 2a end portion; 2b side face; 3 arc contact (second contact); 3a end portion; 4 fixed contact (third contact); 4a contact portion; 4b urging portion; 4c gap-forming portion; 5 shield; 5a first opening; 5b second opening; 6 engaging mechanism; 7 guide part; 7a side face; 8 engaging part; 9 conductor part; 10 attracting part (first magnetic material part); 11 part to be attracted (second magnetic material part); 11a pivot portion; 11b edge portion; 11c engagement portion; 12 arc; 13, 14 path; 15 urging part; 16 sliding contact; 50 operation axis; 51 switch; 54 movable-side main contact; 54a contact portion; 54b urging portion; 54c gap-forming portion; 55, 56 path.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/JP2016/061270 | 4/6/2016 | WO | 00 |