JPH0338906Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a normally closed contact type arc extinguishing device for a DC electromagnetic contactor.

[Conventional technology]

For example, the arc extinguishing device of a conventional normally closed DC electromagnetic contactor is shown in longitudinal sectional views in FIGS. 9 to 11, respectively.
There are known arc-extinguishing principle diagrams and exploded perspective views of essential parts.

Although only a portion is shown in the figure, they are attached to the front side of the insulating case 1 (upper side in Figure 9) via main circuit terminals 2a and 2b, and are opposed to each other with a space between them, forming a pair. A U-shaped fixed contact 3 is arranged. An interlocking rod 4 is supported between the opposing fixed contacts 3 so as to be slidable in the vertical direction, and at the upper end of the interlocking rod 4 is a movable contact 5 that can bridge between the contacts 3a of the fixed contacts 3. An electromagnet 6, only a portion of which is shown, installed inside the case 1 is connected to the lower end of the interlocking rod 4.

The contact 5a of the movable contact 5 bridges the contact 3a of the fixed contact 3 by the spring force of a return spring (not shown) to maintain a normally closed state. An arc extinguishing device 7 is provided in the opening/closing section constituted by the fixed contact 3 and the movable contact 5, and this arc extinguishing device 7
As shown exploded in the figure, a magnetic pole plate 8, an insulating barrier 9, a permanent magnet 10, a mounting plate 11 and a screw 12,
It consists of 13.

To assemble this DC electromagnetic contactor, first, the magnetic pole plate 8 is fitted into the groove 9a provided in the insulating barrier 9, and the screw 1
Tighten by 2. Next, the permanent magnet 10 is inserted into the U-shaped groove 9b of the insulating barrier 9 from below, and the mounting plate 11 is inserted into the insulating barrier 9 through the mounting hole 1 of the mounting plate 11.
1a and tighten the screw 13 to secure the permanent magnet 10.
prevent it from falling off. This arc extinguishing device 7 is attached together with the fixed contact 3 using screws 30. The spring 14 inserted into the window of the interlocking rod 4 together with the movable contact 5 applies contact pressure to the contact 5a of the movable contact 5 and the contact 3a of the fixed contact 3.

[The problem that the idea aims to solve]

In the DC electromagnetic contactor described above, the current flowing through the main circuit terminals 2a and 2b is limited to one direction, so if the current direction is indicated by arrow A in FIG. 10, the arc 15 at the time of interruption will be A B
When driving in the direction of the arrow, according to Fleming's left-hand rule, the direction of speed φ must be directed from the front toward the paper surface, so the permanent magnet 10
The polarity of the front side must be the S pole, and this is the same for the left and right fixed contacts 3.
Therefore, when assembling the arc extinguishing device 7 shown in FIG.
A permanent magnet 10 is attached to the fixed contact 3 along with the clamping side.
Prepare one each with the polarity direction determined,
It is necessary to clarify on which side each item should be installed and to install it correctly. If you do this incorrectly, the arc 15 will be driven toward the interlocking rod 4, and the interlocking rod 4 will
The spring 14 is exposed to the arc and burnt out, making it unusable. Such a problem also occurs when a user removes the fixed contact 3 for maintenance and inspection and then attaches the arc extinguishing device 7 by mistake. Also,
If the distance between the tip of the movable contactor 5 and the bottom part (vertical part in FIG. 10) of the fixed contactor 3 is small, the length of the arc is limited and the interruption is not completed before the arc reaches the bottom part. An arc persists between the tip of the movable contact 5 and the bottom of the fixed contact 3, and as a result, the breaking time becomes longer and the rated breaking current value is suppressed to a small value. Furthermore, since many screws are required to assemble the arc extinguishing device 7 and the screwing directions of the screws are different, the assembly time is increased.

Therefore, the purpose of the present invention is to eliminate the drawbacks of the conventional devices mentioned above, prevent incorrect installation of the arc extinguisher using permanent magnets, and simplify the assembly of the arc extinguisher itself. Our goal is to provide contactors.

[Means to solve the problem]

The above-mentioned object, according to the present invention, includes a pair of stationary contacts having a U-shape and having a contact fixed to one leg and the other leg fixed to a main circuit terminal and spaced apart from each other; a movable contact that is supported by one end of an interlocking rod that is supported so as to be able to reciprocate between the fixed contacts, and that moves between the legs of the U-shaped fixed contact to bridge the contact points of the pair of fixed contacts; , an electromagnet that drives the interlocking rod to separate the movable contact from the contact of the fixed contact, and an electromagnet arranged to sandwich the contacts of the movable contact and the fixed contact that face each other and are coupled to each other via a permanent magnet. and an arc extinguishing device having a magnetic pole plate whose opposing surface is covered with an insulating barrier, wherein the insulating barrier is arranged to cover an inner wall surface of a U-shaped bottom portion of the fixed contact. The insulation barrier is extended to the fixed contact and the extension is coupled to the fixed contact to fix the insulating barrier to the fixed contact.

[Effect]

In the present invention, the insulating barrier is extended to cover the inner wall surface of the U-shaped bottom part of the fixed contact, and the extended part is coupled to the fixed contact to fix the insulating barrier to the fixed contact. Since the arc extinguishing device is attached to the fixed contact, incorrect installation of the arc extinguishing device is prevented, and the inner wall surface of the bottom of the U-shaped fixed contact is covered by the extension of the insulating barrier. The arc generated between the movable contact and the fixed contact when they are separated does not migrate to the bottom of the fixed contact.

〔Example〕

Next, one embodiment of the present invention will be described in detail based on the drawings. Figures 1 to 5 show an embodiment of this invention, with Figure 1 being a vertical cross-sectional view of the entire contact portion, Figure 2 being an enlarged side view of the main part of Figure 1, and Figure 3 being a cross-sectional view of the entire contact portion. 4 is a perspective view of the fixed contact, and FIG. 5 is an exploded perspective view of the arc extinguishing device. In the figure, the same parts as those of the conventional device shown in FIG. 9 are designated by the same reference numerals, and the differences will be explained.

The difference between this embodiment and the conventional device is that a part of the insulating barrier is extended to form a cover for the U-shaped bottom of the fixed contact, and that the arc extinguishing device is directly attached to the fixed contact. The arc extinguishing device is integrated with the fixed contact even when removed from the main body, and the magnetic pole plate and permanent magnet can be attached to the insulating barrier with one touch without using screws. The advantage is that metal fittings are used, and the polarity of the permanent magnet can be confirmed in the connected state.

To explain in detail with reference to the drawings, the arc extinguishing device 17 is composed of a magnetic pole plate 8, a permanent magnet 10, an insulating barrier 18 and a coupling fitting 19, which are different from conventional devices, as shown in FIG. The insulating barrier 18 includes a pole-side barrier portion 20 that covers the pole plate 8 and the permanent magnet 10.
The U-shaped bottom portion 3b of the fixed contact 3 is integrated with the magnetic pole side barrier portion 20 via the connecting portion 21.
(vertical portion in FIG. 1) and a conductor-side barrier portion 22 that covers the inner wall surface. The magnetic pole side barrier portion 20 includes a recess 20a into which the magnetic pole plate 8 is fitted;
It is provided with a U-shaped groove 20b into which the permanent magnet 10 is fitted and both ends of which are in contact with the magnetic pole plate 8, and four protrusions 20c which engage coupling fittings 19, which will be described later. The connecting portion 21 includes a screwdriver insertion hole 21a for tightening the fixed contact 3 to the main circuit terminals 2a, 2b with a screw 24. The conductor-side barrier portion 22 has a U-shaped cross section, into which the bottom portion 3b of the fixed contact 3 is fitted, so that it covers not only the inner wall surface but also the cut surface, and the fixed contact is located at the bottom of the U-shape. A screw hole 22a is provided for integration with 3. The coupling fitting 19 is made of an elastic thin plate material and is bent into a U-shape in which the inner dimensions of the pole pieces match the dimensions between the magnetic pole plates 8 that sandwich the permanent magnet 10, and an insulating barrier 18 is provided on both sides of the ends of the pole pieces. A locking claw 19a that engages with the protrusion 20c of the magnetic pole side barrier portion 20 is provided, and a protrusion 19b cut and raised from the bottom is provided on one of the corners (ridges) bent in a U-shape, and on the other side. Square holes 19c are provided for equalizing the spring forces of both leg pieces.

On the other hand, the attachment of the fixed contact 3 to the main circuit terminals 2a, 2b is different from the simultaneous tightening of the arc extinguishing device 7 in the conventional device shown in FIG. Screw 23 in hole 3c
After that, the fixed contact 3 is fastened with screws 24. Therefore, fixed contact 3
Even if the arc extinguishing device 17 is removed from the main circuit terminals 2a, 2b for inspection and maintenance, etc., the arc extinguishing device 17 is integrated and will not fall off, be installed incorrectly, or be forgotten. In addition, the fixed contact 3 has a screw 24 on the mounting side leg piece 3d.
A through hole 3g for inserting a screwdriver is provided in the leg piece 3f on the side of the contact 3a. The arc extinguishing device 17 attached to the fixed contact 3 is assembled by fitting the magnetic pole plates 8 and the permanent magnets 10 into the recesses 20a and the grooves 20b of the magnetic pole side barrier portion 20, respectively, and attaching the two magnetic pole plates 8 to the permanent magnets 10. Set it in the recess 20a in such a manner that the After that, when the coupling fitting 19 is pushed in from below, both leg pieces are deformed so as to be opened, and the locking claw 19a is inserted into the protrusion 20.
When the magnetic pole plate 8 and the permanent magnet 10 are fixed to each other stably, the magnetic pole plate 8 and the permanent magnet 10 are fixed. Therefore, its assembly is extremely simple compared to conventional devices. Here, in this embodiment, a protrusion 19b is formed at one corner of the coupling fitting 19 so as to cut and raise the bottom part, and it determines the attachment of the fixed contact 3 to which the arc extinguishing device 17 is attached, and also a permanent magnet. In order to be able to confirm the polarity of 10 (for example, by coloring the N pole) from the outside after assembly, the entire protrusion 19b side is determined to be the N pole, for example. As a result, if the direction of current flowing through the main circuit terminal 2a in FIG. 1 is from the right side to the left side in FIG.
If the one using the coupling fitting 19 in the direction shown in Fig. 3 is installed on the left side, and the one using the coupling fitting 19 reversed as shown in Fig. 5 is installed on the right side, the arc will be driven in the correct direction, that is, outward. can do. For this purpose, as shown in FIGS. 1 to 3, a recess 1b into which a protrusion 19a of the arc extinguishing device 17 fits is provided in the pole spacing wall 1a of the case 1. The recess 1b is only on one side of the partition wall 1a for each pole, so if you try to attach it in the opposite direction, the protrusion 19
b gets in the way and prevents incorrect installation.

In addition, as a measure to prevent incorrect installation, as shown in FIG. 6, two types of magnetic pole plates 25 provided with other protrusions 25a of the magnetic pole plate 8 are prepared, and as shown in FIGS. 7 and 8. It can also be formed by having protrusions 26a on both sides in advance like the insulating barrier 26, and cutting out the unnecessary portions by additional processing.

[Effect of idea]

As explained above, according to the present invention, a pair of fixed contacts are arranged at intervals, with a contact fixed to one leg formed in a U-shape and fixed to the main circuit terminal on the other leg. and a movable contact that is supported by one end of an interlocking rod that is supported so as to be able to reciprocate between the fixed contacts, and that moves between the legs of the U-shaped fixed contact to bridge the contact points of the pair of fixed contacts. an electromagnet that drives the interlocking rod to separate the movable contact from the contact of the fixed contact, and an electromagnet that is arranged to sandwich the contacts of the movable contact and the fixed contact that face each other, and is connected to each other through a permanent magnet. and an arc extinguishing device having a magnetic pole plate that is coupled to each other and whose opposing surfaces are covered with an insulating barrier, the insulating barrier covering an inner wall surface of the U-shaped bottom portion of the fixed contact. Since the arc extinguishing device is attached to the stationary contact by extending the extended portion to the fixed contact and fixing the insulating barrier to the fixed contact, incorrect installation of the arc extinguishing device is prevented. Since the bottom part of the U-shaped fixed contact is covered by the extension of the insulating barrier, the arc generated between the fixed contact and the movable contact when they are separated is prevented from collapsing. Since it does not migrate to the bottom of the letter-shaped fixed contact, the distance between the tip of the movable contact and the bottom of the fixed contact can be reduced, allowing for miniaturization without sacrificing breaking performance. DC electromagnetic contact can be provided.

In addition, assembly of the arc extinguishing device is easy by using a coupling fitting that has locking pieces for the insulating barrier on both legs formed in a U-shape to attach the permanent magnet and the magnetic pole plate to the insulating barrier. At the same time, it is possible to provide a DC electromagnetic contactor that will not fall off, be installed incorrectly, or be forgotten.

[Brief explanation of the drawing]

1 to 5 each show an embodiment of the DC electromagnetic contactor according to this invention, FIG. 1 is a longitudinal sectional view of the contact portion, FIG. 2 is an enlarged side view of the arc extinguishing device of FIG. 1, Fig. 3 is a view taken from arrow P in Fig. 2, Fig. 4 is a perspective view of the fixed contact, Fig. 5 is an exploded perspective view of the arc extinguishing device, and Figs. 6 to 8 are each a view of this invention. 9 is a perspective view, a front view, and a side view showing different embodiments. FIGS. 9 to 11 each show an example of a conventional DC electromagnetic contactor, and FIG. 9 is a longitudinal sectional view of a contact portion, and FIG. The figure is a diagram of the arc drive principle, and FIG. 11 is an exploded perspective view of the arc extinguishing device of FIG. 9. 2a, 2b: Main circuit terminal, 3: Fixed contact, 3
a, 5a: contact, 4: interlocking rod, 5: movable contact,
6: Electromagnet, 8: Magnetic pole plate, 10: Permanent magnet, 1
7: Arc extinguishing device, 18: Insulating barrier, 19: Locking claw, 19a: Projection, 22: Conductor side barrier portion.

Claims (1)

[Claims for Utility Model Registration] 1. A pair of stationary contacts formed in a U-shape, with a contact fixed to one leg and the other leg fixed to a main circuit terminal, spaced apart from each other; a movable contact supported by one end of an interlocking rod that is supported to reciprocate between the fixed contacts and moves between the legs of the U-shaped fixed contact to bridge the contacts of the pair of fixed contacts; An electromagnet that drives the interlocking rod to separate the movable contact from the contact of the fixed contact, and an electromagnet arranged to sandwich the opposing contacts of the movable contact and the fixed contact and coupled to each other via a permanent magnet. and an arc extinguisher having a magnetic pole plate whose opposing surface is covered with an insulating barrier, the insulating barrier being extended to cover the inner wall surface of the U-shaped bottom of the fixed contact. A DC electromagnetic contactor characterized in that the extension portion is coupled to a fixed contact and the insulating barrier is fixed to the fixed contact. 2. In the electromagnetic contactor described in claim 1 of the utility model registration claim, the arc extinguishing device comprises two U-shaped legs that press from both sides a magnetic pole plate that is attracted to a permanent magnet attached to an insulating barrier, and the two legs. 1. A DC electromagnetic contactor characterized in that one piece has a locking pawl that engages with the insulating barrier, and one U-shaped ridge has a coupling fitting consisting of a protrusion that projects from the leg piece.