The present invention relates to a switch, such as a gas-insulated switchgear, and particularly relates to a switch having a blade-type moving contact, which is rotatably and pivotally supported and reciprocates such that a free end of the blade-type moving contact draws a rotation locus, and a fixed contact that has conduction members with which the moving contact comes into contact.
In a switch having a blade-type moving contact, which is rotatably and pivotally supported and reciprocates such that its free end draws a rotation locus, and a fixed contact that has conduction members with which the moving contact comes into contact, a pressurizing member that biases the conduction members in a direction in which tip ends of the conduction members approach each other is provided. Thus, the conduction members sandwich the moving contact with an appropriate pressure. The fixed contact is supported such that the fixed contact is movable with respect to the moving contact.
The pressurizing member applies a force in a direction in which the tip ends of a pair of the conduction members, which are arranged opposedly and substantially in parallel, approach each other. For example, a method of arranging a coil spring between a pair of conduction members and a method of arranging laminated leaf-springs on outer sides of conduction members have been proposed (see, for example, Patent Documents 1 and 2). As for a supporting method of the fixed contact, there has been proposed a method of supporting connecting conductors using bolts at both ends in a direction along which the moving contact is brought into contact (see, for example, Patent Document 2).
The space between the pair of conduction members is the space into which the blade-type moving contact enters. Therefore, when a coil spring is arranged in the space, the fixed contact becomes large in a length direction of the conduction members. Furthermore, because every pair of conduction members requires a coil spring and a pin that engages with the coil spring, the number of parts is increased. Thus, an improvement has been desired.
Generally, a predetermined opening width is maintained between the pair of conduction members, which are separate, so that the blade-type moving contact can enter normally. A regulating member that regulates the conduction members to predetermined positions is located substantially at a central portion between the pair of conduction members. The opening width between the tip ends of the conduction members tend to vary due to dimensional tolerances of the conduction members and the regulating members. Thus, an improvement has been desired.
The laminated leaf-springs can be arranged on outer sides of the conduction members while relaxing an excessive stress applied to substantially central portions of the leaf springs; however, the number of parts of the leaf springs is increased. Furthermore, it is necessary to integrally fasten leaf springs, which are laminated, to an outer frame (cover) using a bolt in order to fix the laminated leaf-spring. Accordingly, an electric field tends to be concentrated on the bolt, which is not preferable in view of shielding the electric field. Thus, an improvement has been desired.
When the fixed contact is supported at both ends in a direction, along which the moving contact is brought into contact, and when a contact conductor is arranged to cover peripheries thereof for the purpose such as downsizing the entire switch and optimizing the internal structure, there is no assembling space for mounting the fixed contact and the assembling work is hindered. Thus, an improvement has been desired.
The present invention has been made in view of the above, and an object of the present invention is to provide a switch capable of downsizing an apparatus and keeping a predetermined opening width between tip ends of conduction members with a simple method. Another object of the present invention is to provide a switch capable of movably supporting a fixed contact with a simple structure and with a simple assembling method while preventing an increase of the apparatus size.
To solve the problem described above and achieve the object, a switch according to a first invention has a blade-type moving contact, which is rotatably and pivotally supported and reciprocates such that a free end of the blade-type moving contact draws a rotation locus, and a fixed contact that has conduction members with which the moving contact comes into contact, wherein the fixed contact has a pair of the conduction members that are arranged opposedly and substantially in parallel to each other such that tip ends of the conduction members are oriented toward the opening, a pedestal member that tiltably supports bases of the conduction members, a pressurizing member that biases the conduction members in a direction in which the tip ends of the conduction members approach each other, and a shielding member that covers peripheries of at least the conduction members and the pressurizing member and shields them from an outside electric field, the pressurizing member is arranged on an outer side of the opposed conduction members, and the shielding member engages with the tip ends of the conduction members, overcomes a biasing force of the pressurizing member, and maintains an opening width between the tip ends of the conduction members at a predetermined width.
A switch according to a second invention has a blade-type moving contact, which is rotatably and pivotally supported and reciprocates such that a free end of the blade-type moving contact draws a rotation locus, and a fixed contact that has conduction members with which the moving contact comes into contact, wherein the fixed contact has a pair of the conduction members that are arranged opposedly and substantially in parallel to each other such that tip ends of the conduction members are oriented toward the opening, a pedestal member that tiltably supports bases of the conduction members, a pressurizing member that biases the conduction members in a direction in which the tip ends of the conduction members approach each other, and a shielding member that covers a periphery of at least the conduction members and shields them from an outside electric field, and the pedestal member is supported by a support conductor with a predetermined play so that the pedestal member is movable with respect to the moving contact.
According to the switch of the first invention, the pressurizing member is arranged on an outer side of the opposed conduction members. The shielding member engages with the tip end of the conduction member. This engagement overcomes a biasing force of the pressurizing member and thus the opening width between the tip ends of the conduction members is maintained at a predetermined width. Therefore, the apparatus can be downsized with a simple structure, and the opening width between the tip ends of the conduction members can be accurately maintained at a predetermined width.
According to the switch of the second invention, the pedestal member is supported by the support conductor with a predetermined play such that the pedestal member is movable with respect to the moving contact. Thus, it is possible to prevent an increase of the apparatus size, and the fixed contact can be movably supported with a simple structure and a simple assembling method.
Exemplary embodiments of a switch according to the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments.
Three movable-side support conductors 28 supported by the insulation spacer 12 via a spacer connecting conductor 29 extend toward a center of the tank 10 at further different positions in the tank 10. As shown in
Blade-type (plate-like) moving contacts 26 are pivotally supported by the insulation operating shafts 30 and provided on the slit conductors 27. Each of the moving contact 26 is formed into a substantially thin long plate shape extending in the radial direction from the rotation center, and the moving contact 26 rotates around the rotation center of the insulation operating shaft 30 such that a free end of the moving contact 26 draws a rotation locus L. A tip free end 26a comes into contact with the fixed contact 20 or the grounding fixed contact 23. As shown in
Each of the fixed contact 20 and the grounding fixed contact 23 has a substantially U-shaped cross section formed with an opening 20a through which the moving contact 26 enters. The opening 20a opens toward the insulation operating shaft 30. The fixed contact 20 and the grounding fixed contact 23 have substantially the same structures, and the structure of the fixed contact 20 is mainly described below.
As shown in
The fixed contact 20 includes six pairs of conduction members 31, which are arranged opposedly and in parallel to each other. Tip ends of the conduction members 31 are oriented toward the opening 20a. The fixed contact 20 also includes a support frame (pedestal member) 33 that tiltably supports bases 31a of the conduction members 31, a leaf spring (pressurizing member) 43 that biases the conduction members 31 in a direction in which tip ends of the conduction members 31 approach each other, and an outer frame (shielding member) 45 that covers peripheries of the conduction member 31, the support frame 33 and the leaf spring 43 and shields them from an outside electric field.
Each of the conduction members 31 has a sponge-gourd flat plate-shaped contour and is provided at its side with a curved portion 31c (
The leaf spring (pressurizing member) 43 is a thin leaf spring having a dogleg-shape in cross section. The leaf spring 43 is arranged on an outer side of the opposed conduction members 31 (between the conduction member 31 and the outer frame 45) (
The outer frame 45 in the recessed-side of the dogleg-shape in cross section is provided with a projection 45b that regulate a warp of the leaf spring 43 to a predetermined amount. By providing the projection 45b, a warp of the leaf spring 43 when the moving contact 26 becomes eccentric and comes into contact is regulated to a predetermined value, and it is possible to prevent an excessive stress from being applied to the leaf spring 43. A position where the projection 45b is provided is in the recessed-side of the L-shape of the leaf spring 43. The projection 45b may be provided on the outer frame 45 or on a back surface of the leaf spring 43.
The slits 43a may be formed only in intermediate portions excluding both ends or may be formed over the entire length such that the tooth portions 43c are individually divided. It is preferable to arrange the leaf spring 43 such that the doglegged top is located on the side of the conduction member 31 as described above. However, even if the direction is reversed due to interference with another member or the like, substantially the same effect can be achieved.
The outer frame (shielding member) 45 is formed using casting that has high flexibility in terms of shape and that is effective for shielding the electric field. The outer frame 45 forms a shell of the fixed contact 20. The outer frame 45 is formed into a substantially box-like shape covering peripheries of the pair of conduction members 31 opposed substantially in parallel to each other, the support frame 33, and the leaf springs 43. The opening 20a through which the blade-type moving contact 26 enters is formed at a location corresponding to a gap between the tip ends of the conduction members 31. A portion of the outer frame 45 on the side of the connecting conductor 22 is opened for inserting an internal part and fixing it to the connecting conductor 22. Opposed edges of the tip end facing the opening 20a are bent inward so that a cross section thereof has a substantially L-shape. The outer frame 45 overcomes a biasing force of the leaf spring 43 by engaging the tip end that is formed as an engaging portion and that is bent so that a cross section thereof has substantially an L-shape, with a notch 31b formed at a tip end of the conduction member 31 as a to-be-engaged portion. Thus, the outer frame 45 maintains the opening width between the tip ends of the conduction members 31 at a predetermined width. The outer frame 45 is provided at its end on the side of the connecting conductor 22 with a U-shaped fastening notch. The support rod 35 is inserted into the fastening notch, and is fastened to the support frame 33 together with the support rod 35 by the fastening member 37 that is threadedly engaged with the support rod 35 (
The connecting conductor 22 supports the entire fixed contact 20 by supporting the support frame 33. The connecting conductor 22 is provided at its tip end with a protrusion 22a having a height D greater than a plate thickness of the frame portion 33a (
The two retaining members 41 each having the screw and the washer are inserted from the opening 20a of the outer frames 45 and are fastened to the protrusion 22a of the connecting conductor 22 (
In the switch having such a structure, the leaf springs (pressurizing member) 43 are arranged on outer sides of the opposed conduction members 31. Therefore, the space between the pair of conduction members 31 that are opposed to and in parallel to each other can be effectively utilized, and the height size of the fixed contact 20 can be reduced. By using the leaf springs 43 having the small thickness as the pressurizing member, the width size of the fixed contact 20 can be reduced and thus the entire switch can be downsized. The number of parts can be reduced as compared with a pressurizing structure of a conventional power-actuated type (a type in which conduction member is pressurized by another pressurizing member), and the size can be largely reduced as compared with a pressurizing structure of a conventional own-power type (a type in which conduction member is pressurized by bending of the conduction member itself).
The tip end of the outer frame 45 is engaged with the notch 31b formed at the tip end of the conduction member 31. With this configuration, the opening width between the tip ends of the conduction members 31 is maintained precisely. Therefore, a variation in load when the moving contact 26 comes into contact and separates can be regulated and the motion can be stabilized. The tip end of the outer frame 45 is utilized as a regulating structure. With this configuration, the number of parts is not increased and the regulating structure can be realized without increasing the entire size of the switch.
Furthermore, in the switch according to the present embodiment, the support frame (pedestal member) is supported by the connecting conductor (support conductor) 22 with a predetermined play. Therefore, the fixed contact 20 is movable with respect to the moving contact 26 with the simple structure and with the easy assembling method. When the moving contact 26 enters in the fixed contact 20, the motion becomes smooth and the reliability is enhanced.
Furthermore, in the switch according to the present embodiment, the plurality of conduction members 31 are provided at predetermined distances from one another in the direction of the rotation locus of the moving contact 26. The leaf spring (pressurizing member) 43 has the same number of the tooth portions 43c as that of the conduction members 31 as a partial slit structure. Therefore, a contact pressure can be applied to the plurality of conduction members 31 individually, and when the moving contact 26 enters, the conduction members 31 can be independently operated. Thus, it is possible to prevent the inserting force from increasing. Because the leaf spring 43 is formed to have an integrated structure with partial slits, the handling thereof is facilitated.
The switch according to the present invention is useful when it is applied to a switch that has a blade-type moving contact, which is rotatably and pivotally supported and reciprocates such that its free end draws a rotation locus, and a fixed contact that has a conduction member with which the moving contact comes into contact.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2007/071560 | 11/6/2007 | WO | 00 | 5/5/2010 |
Publishing Document | Publishing Date | Country | Kind |
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WO2009/060512 | 5/14/2009 | WO | A |
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4678876 | Westbrock et al. | Jul 1987 | A |
5566818 | Kuboyama et al. | Oct 1996 | A |
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Number | Date | Country | |
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20100219053 A1 | Sep 2010 | US |