JPH031873Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a switch having a pair of contacts that can be separated relative to each other, and in particular, the contact surface of a rod-shaped contact whose outer peripheral surface is the contact surface. A cover is provided on the contact surface to prevent the contact surface from being soiled by arcing when the contactor is opened and closed, and to suppress temperature rise due to increased contact resistance at the contact portion.

[Conventional technology]

Conventional equipment of this type uses air or SF6 (sulfur hexafluoride).
In a container filled with insulating or arc-extinguishing gas such as gas, there is a pair of contacts that can be moved into and out of contact with each other, i.e., a fixed contact, and a movable contact that is placed opposite to this and that comes into contact with each other through reciprocating motion. Have a child.

In addition, in a device having a puffer-type arc extinguishing device to enhance the arc extinguishing effect, it surrounds the movable contact with a gap, moves together with the movable contact, and extinguishes in the gap between the fixed contact and the fixed contact. A movable cylinder equipped with a nozzle part for spraying an arc gas body and a fixed piston constitute a puffer chamber.

Figures 1 to 3 show an example of a conventional structure, with Figure 1 in the open state, Figure 2 in the closed state, and Figure 3 in the closed state.
The figure shows the state in the middle of opening. In the figure, reference numeral 1 denotes an insulating base such as a bushing that supports a rod-shaped fixed contact 2. Reference numeral 3 denotes a tube-shaped movable contact that moves toward and away from the fixed contact 2 through reciprocating motion, 4 a contact spring that applies contact pressure when both the movable and fixed contacts contact each other, and 5 a contact base that slides onto the conductive base 6. They are movably fitted, and the sliding contact 7 is held by a retaining spring 8 to ensure electrical connection and to enable sliding. Reference numeral 9 denotes a cylinder for the puffer, 10 a drive fitting that engages with a drive mechanism (not shown) to drive the movable part, and 11 a nozzle tapered to cover the contact part of the movable contact with a gap. This structure is linked to child 3. 12 is a piston,
It is fixed to an insulating base such as a bushing (not shown), and works together with the cylinder 9 to perform a puffing action.

From the state shown in FIG. 1, in response to a closing command, the driving mechanism 10 moves toward the fixed contact 2 by a drive mechanism (not shown), drives the cooperating movable contact 3, and brings the two movable fixed contacts into and out of contact. As this process progresses, the movable contactor 3 comes into contact with the fixed contactor 2 and enters the closed state as shown in FIG. At this time, the outer periphery of the end wall 12a of the piston 12 slides with the inner wall of the cylinder 9 while maintaining airtightness, and the cylinder 9 and the piston end wall 12a
The area surrounded by and becomes the patchwork chamber 13.

When the cylinder 9 starts to move in the opening direction, that is, to the right in the figure, in response to the opening command, the gas accumulated in the puffer chamber 13 is pushed out in the direction A of the nozzle 11.
As shown in FIG. 3, the arc B generated upon opening is blown in the direction of the fixed contact 2 by this gas body.

Generally, both movable and fixed contacts are exposed to and affected by the arc generated when they are opened, and furthermore, in the puffer type and blowout type, the arc is blown in a fixed direction, so areas where the arc is concentrated are particularly affected.

[Problem that the invention attempts to solve]

The mating and contacting parts of both movable and fixed contacts as mentioned above are generally coated with oil in order to reduce the resistance when closing and opening for smooth operation, and to keep the contact surfaces clean. However, these oils and fats can be affected by the arc during opening and closing as described above and become carbonized and lose their lubricity, or the carbides can adhere to contact surfaces and stain them, or the oils and fats can become Even if it is not coated, the resin insulators that make up the arc extinguishing chamber around the contact area may adhere to the contact surface with carbide generated by arc heat and become contaminated, increasing contact resistance and causing temperature rise. I was afraid. In addition, to prevent this, it is possible to increase the conductor cross-sectional area of the current-carrying part, or to strengthen the contact spring 4 of the movable contact in order to mechanically remove adhering carbides, etc. It is necessary to increase the input force and shearing force, as well as the driving force.
The handle mechanism in a manual switch and the drive device itself such as an electromagnet in an automatic switch become larger, resulting in an increase in the size and weight of the switch as a whole, resulting in various drawbacks such as an increase in the price of the switch.

[Means for solving problems]

In order to eliminate these drawbacks, the present invention attaches a protective cover to the contact to prevent the contact surface from becoming dirty. Or both, when contact is made, it slides in contact with the other party's contact or an accessory that moves with it, exposing the contact surface of the contact, and when contact is released, it is pushed back by a repulsion spring and makes contact. At the time of separation, the entire contact surface of the contact is covered.

[Effect]

By doing so, the present invention prevents the contact surface of the contactor from coming into contact with the arc generated when the contact is released, thereby preventing the contact surface from being contaminated.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 4 and 5. FIG. 4 shows a state where the contact is closed, and FIG. 5 shows a state where the contact is in the middle of being released. Portions equivalent to or equivalent to those of the conventional example shown in FIGS. 1 to 3 are designated by the same numbers. Points different from the conventional example will be explained with reference to the figures. 14 is a cover for preventing dirt on the contact surface, 15 is a repulsion spring that pushes back the cover 14 when the contact is separated, and 16 is a stopper that restricts the movement of the cover 14. In Figure 4, cover 1 is
4 is in contact with the nozzle 11 and the repulsion spring 1
5 and moves to the left in the figure to expose the contact surface, so there is no problem with energization. FIG. 5 shows a state in the middle of opening, and an arc B is generated between the contacts, and this arc B is blown in the direction A of the fixed contact 2 by the gas blown out from inside the cylinder 9. In this case, since the cover 14 is pushed back by the repulsion spring 15 and covers the current-carrying surface of the fixed contact 2, the arc will not hit this current-carrying surface and there is no risk of contamination. The cover 14 is pushed out to a position where it covers the tip of the current-carrying surface of the contact, and at that position it abuts against a stopper 16 provided on the fixed contact 2, thereby restricting its movement.

In the above, the flange 14 is located at the middle part of the cover 14.
a is provided, and this collar portion 14a is the movable contact 3.
When the contact is made, the cover 14 is pushed back by the movable contact part, exposing the current-carrying surface of the fixed contact 2 and making it possible to make contact. When the movable part retreats, the cover 14 is pushed back by the repulsion spring 15 to cover the current-carrying surface of the fixed contact 2. In this case, the movable part abutting part is the tip of the nozzle 11, and this movable part abutting part is in a position considerably advanced from the movable contact tip 3a, but the abutting part of the cover 14 that comes into contact with it is The flange portion 14a is in a position retracted from the tip of the cover 14, and when the movable part abutting portion moves together in contact with the cover 14, the tip 14b of the cover 14 approaches the tip 3a of the movable contact. The current state will be maintained. Therefore, when the movable contact 3 separates from the fixed contact 2, the entire contact surface of the fixed contact 2 is covered by the cover 14.

Note that the method of covering the entire contact surface of the contact with the cover 14 at the time of contact/release is as follows:
The method is not limited to the above method.

FIG. 6 shows another embodiment of the cover, in which 17 is a cover, 18 is a repulsion spring, and the repulsion spring 18 replaces the cover 14.
7 to prevent the repulsion spring 18 from being damaged by arc heat. The movement of the cover 17 is restricted by the cover end 17a and the end 19a of the stopper 19. The cover 17 is made of arc-resistant metal or insulator.

FIG. 7 shows still another embodiment, in which a cover 20 is attached to the inner surface contact part of the movable contact 3, and a repulsion spring 21 normally covers the current-carrying surface up to the tip of the movable contact, and the movable contact 3 is connected to the fixed contact. 2, the cover 20 is pushed into contact with the fixed contact 2 to expose the contact surface and come into contact with the fixed contact 2. When the contact is separated, the cover 20 is pushed back by the repulsion spring 21 and covers the contact surface of the movable contact, so that the arc generated by the separation does not hit the contact surface, and contaminants do not adhere to the contact surface. It won't get dirty.

In the above, the devices shown in FIGS. 4 to 6 are provided with a protective cover for the contact surface of the fixed contact, and the device shown in FIG.
A protective cover is provided for the contact surface of the movable contact. The protective covers for both movable and fixed contacts can be installed individually.
It is also possible to perform both at the same time.

In addition, items that touch and move the protective cover,
It may be a contact portion such as an end surface of a mating contact, an end surface of a nozzle 11 that is attached to the mating contact and moves together, or other accessories. In short, what kind of mechanism can be used if the covers 14, 17, and 20 are made to slide using the motion accompanying the contact and separation of both movable and fixed contacts, and cover the entire contact surface at the time of contact and separation when an arc occurs? There is no problem even if it is done via .

[Effect of idea]

By attaching a contact surface protection cover to the contact as described above, the present invention can prevent the contact surface of the contact from being contaminated by arcing caused by load switching, and the contact resistance of the current-carrying surface will not increase. It is possible to prevent troubles such as an abnormal temperature rise in the parts, the current-carrying part can be made smaller, the material cost can be reduced, and a small and lightweight switch can be obtained at a low price.

[Brief explanation of drawings]

Figures 1 to 3 show conventional embodiments, with Figure 1 being a vertical cross-sectional view of the main part showing the open state, Figure 2 being a vertical cross-sectional view of the main part showing the closing operation completed state, and Figure 3 being the open circuit. 4 and 5 show an embodiment of the present invention, FIG. 4 is a vertical sectional view of the main part showing the state in which the closing operation is completed, and FIG. 5 is the opening operation. 6 and 7 show other embodiments of the present invention, FIG. 6 is a sectional view of the main part of the fixed contact in the open operating state, and FIG. 7 is the same. It is a sectional view of the main part of a movable contact. 2: Fixed contact, 3: Movable contact, 9: Cylinder, 10: Drive fitting, 11: Nozzle, 12: Piston, 14: Cover.

Claims (1)

[Scope of utility model registration request] In a switch having a pair of contacts that can be relatively connected and separated, one or both of the contacts slides in contact with the other contact or an accessory that moves together with it when making contact, and A contact surface protection cover is provided, which exposes the contact surface of a contact, is pushed back by a repulsion spring when the contact is released, and covers the entire contact surface of the contact when the contact is released. Switch contacts with.