JPH0330971Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] This invention relates to a DC electromagnetic contactor that uses a permanent magnet as an arc extinguisher.

It is generally desired that this type of DC electromagnetic contactor be small, have good arc resistance, and be easy to assemble.

[Prior art and its problems]

Examples of conventional DC electromagnetic contactors equipped with arc extinguishing devices using permanent magnets include those shown in FIGS. 8 to 10.
The one shown in the figure is known. This DC electromagnetic contactor is a three-pole type, with normally open contacts on both sides for normal opening and closing of electrical circuits, and a normally closed contact (not shown) in the center used for shorting resistance in dynamic brakes, for example. It is configured to be incorporated. In the figure, a partition wall 1a is provided on the front side of an insulating case 1 to ensure insulation between each pole.
Fixed contacts 2a and 2b, which face each other at a vertical interval and also serve as main circuit terminals, are disposed between them. An interlocking rod 3 is supported between the opposing fixed contacts 2a and 2b so as to be able to slide freely in the left and right directions as shown in FIG. A movable contactor 4 is inserted together with a contact spring 5, and the other end of the interlocking rod 3 is connected to an electromagnet 6 installed inside the insulating case 1. The normally open side opening/closing part made up of both fixed and movable contacts 2a, 2b, and 4 is covered with an arc extinguishing chamber cover 7, and the arc extinguishing chamber cover 7 is fitted with screws inserted into mounting arms 7a provided on both sides. 8 is attached to the insulating case 1.
The arc-extinguishing chamber cover 7 also has a predetermined position on its inner wall.
A permanent magnet 9 with a polarity perpendicular to the current direction is attached to a metal fitting 10.
It is screwed through.

In such a conventional device, when the current is interrupted in the normally open opening/closing section, the partition wall 1a of the insulating case 1 and the arc extinguishing chamber cover 7 are exposed to the arc generated at that time and are worn out. .
Therefore, in order to reduce wear and tear and extend the service life, it is necessary to select materials for the insulation case 1 and arc extinguishing chamber cover 7 that have good arc resistance, that is, expensive materials, or to increase the arc extinguishing space, that is, to increase the size. It has disadvantages such as: For this reason, arc-resistant thermosetting resin is generally used for the arc-extinguishing chamber cover 7, which requires screws to be installed, resulting in poor workability in terms of both processing and assembly.
Furthermore, the permanent magnet 9 for driving the arc has the disadvantage that if it is to obtain the required magnetic flux density of the opening/closing part from a configuration without magnetic pole plates, a large permanent magnet is required and the permanent magnet becomes expensive.

[Purpose of invention]

This idea eliminates the above-mentioned drawbacks of the conventional method and allows the use of low-cost materials for the arc extinguishing chamber, including the insulating case, without shortening the life of the arc. The purpose of the present invention is to provide an inexpensive DC electromagnetic contactor that uses small permanent magnets without degrading performance.

[Main points of the invention] In order to achieve the above-mentioned purpose, the main points of this invention are: a pair of fixed contacts facing each other with a distance between them; A movable contact supported by a supported interlocking rod and bridging the fixed contact, an electromagnet that drives the interlocking rod and controls contact and separation between the fixed contact and the movable contact, and a magnetic pole perpendicular to the current direction. In a DC magnetic contactor equipped with a break chamber having a permanent magnet,
The arc extinguishing chamber is equipped with an upper cover molded from thermoplastic resin, a permanent magnet molded from thermosetting resin and having a polarity perpendicular to the current direction, and two magnetic pole plates that are attracted to the permanent magnet. The arc shielding block is constructed by a shielding block, and the arc shielding block and the upper cover are integrated by engaging with a locking hook provided on the upper cover. According to the present invention, a low-cost thermoplastic resin can be used for the parts other than those exposed to the arc, so it is inexpensive, and since there is no need for a large insulating space, it is possible to downsize.

[Example of idea]

1 to 7 are views showing an embodiment of the DC electromagnetic contactor according to this invention, in which FIG. 1 is a longitudinal cross-sectional view of the contact portion thereof, and FIG. 2 is a cross-sectional view of the contact portion.
Figure 3 is a plan view of the arc extinguishing chamber, Figure 4 is a partially cutaway side view of Figure 3, Figure 5 is a front view of Figure 3,
6 and 7 are enlarged perspective views of the main parts of FIG. 3. In the figure, the same parts as those of the conventional device shown in FIG. 8 are given the same reference numerals, and the differences will be explained. The differences between this embodiment and the conventional device can be summarized as follows: The arc extinguishing chamber is divided into an upper cover and an arc shielding block that can be combined with one touch, and the upper cover is made of inexpensive thermoplastic resin and the arc shielding block is made of arc-resistant material. By molding each of them from a certain thermosetting resin and providing a magnetic pole plate, the size of the permanent magnet is reduced, and as a result, it is possible to use a general phenolic resin for the insulating case 1. The DC electromagnetic contactor in this embodiment is a three-pole type in which the center pole is a normally closed contact and both sides are normally open contacts, similar to the conventional device shown in FIG. It is composed of an upper cover 11 formed by molding and four arc shielding blocks 12 formed by molding a thermosetting resin with good arc resistance. The upper cover 11 is provided with a flat front plate 11a and on both sides of the front plate 11a,
The hook 11b can be locked to the locking part of the insulating case 1 with just one touch of pressure, and the arc shielding block 12, which is provided at each of four locations near the opening/closing part on the normally closed contact side of the front plate 11a, can be locked with one touch. It is provided with a hook 11c with an attachable claw facing outward. In addition, the front plate 11a has a square window 11d penetrating the front plate 11a on the hook side corresponding to the base of each hook 11c, a U-shaped wall 11e arranged to face each hook 11c, and a shielding wall 11f at the center pole.
and is provided. The arc shielding block 12 is formed into an elongated, substantially rectangular tube shape, and has a U-shaped groove 12a for storing the permanent magnet 9 on the side in contact with the back surface of the top cover 11, and a side wall 12b parallel to the U-shaped groove 12a.
The gas vent hole 12c provided in the gas vent hole 1
2c and a projection 12d that can be fitted into a square window 11d of the top cover 11. The arc shielding block 12 also includes guide recesses 12f for magnetic pole plates, which will be described later, provided on both side walls 12e that sandwich the movable contact 4 and fixed contacts 2a, 2b.
The hook 11 of the top cover 11 is provided on the side wall 12g opposite to the side wall 12b where the gas vent hole 12c is located.
The protective wall 1 is bent and extended inward to the anti-gassing hole 12c of the side wall 12b.
2i. The magnetic pole plates 13 are bilaterally symmetrical, that is, the same plate is used on the back, and one end is attracted to the permanent magnet 9 attached to the arc shielding block 12 and is fitted into the guide recess 12f. has been done.

To assemble the arc extinguishing chamber 20 (see FIGS. 6 and 7), first insert the U-shaped groove 12 in the arc shielding block 12.
A permanent magnet 9 is fitted into the guide recess 12f while attracting the magnetic pole plate 13 from both sides. At this point, the members only need to be locked to each other, and there is no need for adhesives, screws, etc. Four pieces in this state are prepared and successively pushed into the portion of the upper cover 11 surrounded by the corresponding hook 11c and the opposing U-shaped wall 11e. As a result, the protrusion 12d of the arc shielding block 12 fits into the upper cover 11 and the corner window 11d, and the stepped portion 12
The hook 11c is engaged with the hook 11c, and the other three surfaces are fitted and pressed inside the U-shaped wall 11e, thereby fixing the permanent magnet 9, the magnetic pole plate 13, and the arc shielding block 12. Here, the hook 11 of the upper cover 11
Since c is located at one location, it is easy to judge that the bonding state is unstable at first glance.In other words, there is anxiety about the force in the direction of the arrow P in Fig. 4, but the protrusion 12d is connected to the square window 11d.
Since the protrusion 12d is fitted into the protrusion 12d, there is no problem since the protrusion 12d acts as a stopper against the rotational force in the same direction using the engagement of the hook 11c as a fulcrum. Furthermore, if the U-shaped wall 11e side is also engaged with a hook, this part is likely to be exposed to arcing when the current is cut off, and thermoplastic resin will be rapidly consumed, which will greatly reduce the meaning of the split configuration. From this point of view as well, the one-sided hook method is superior. In this embodiment, since the leaf spring 14 is used as the fixing portion of the fixed contacts 2a and 2b, the protective wall 12i extends to the side wall 12b of the arc shielding block 12, so that the leaf spring 14 There are advantages that the fixed contacts 2a and 2b do not fall off due to burnout, resulting in a longer electrical life, and as mentioned above, inexpensive wood powder phenol resin or the like can be used for the insulating case of the main body.

[Effect of idea]

According to this invention, the arc extinguishing chamber is divided into a thermoplastic upper cover that can be connected with one touch and an arc-resistant arc shielding block, and a magnetic pole plate is provided on the permanent magnet for magnetic blowing. Since the service life is extended and there is no need to provide a large insulating space, it is possible to provide a compact DC magnetic contactor with improved breaking performance and electrical life. In addition, the upper cover is molded from thermoplastic resin, and the arc shielding block is molded from thermosetting resin, and the arc shielding block is engaged with an engaging hook provided on the upper cover to integrate the arc shielding block and the upper cover. Even if the electromagnetic contactor itself vibrates due to the operation of the electromagnetic contactor, since the arc shielding block and the upper cover are each molded from synthetic resin, the engaging parts will not wear out due to friction. If the arc shielding block is made of an arc-resistant material that is different from synthetic resin and is less likely to generate powder, the vibration may generate a large amount of abrasion powder, which may have an adverse effect on the contact area. This has the effect that the contact reliability of the contact portion does not deteriorate.

[Brief explanation of the drawing]

Figures 1 to 7 are diagrams showing an embodiment of the DC magnetic contactor according to this invention, in which Figure 1 is a vertical cross-section of the contact portion, Figure 2 is a cross-sectional view of the contact portion, and Figure 3 is an arc extinguishing chamber. 4 is a partially cutaway side view of FIG. 3, FIG. 5 is a front view of FIG. 3, and FIGS. 6 and 7.
The figure is a perspective view of the main part of Figure 3, Figures 8 to 10 are diagrams showing an example of a conventional DC magnetic contactor, Figure 8 is a side view showing a vertical cross section in the upper half, and Figure 9 is a side view of a conventional DC magnetic contactor. FIG. 8 is a plan view, and FIG. 10 is a perspective view of the arc extinguishing chamber. 2a, 2b... fixed contact, 3... interlocking rod, 4
...Movable contactor, 6...Electromagnet, 9...Permanent magnet, 11...Top cover, 11c...Hook, 1
1d... Corner window, 12... Arc shielding block, 1
2a...U-shaped groove, 12b...side wall, 12c...
Gas vent hole, 12d...protrusion, 12e...both side walls, 12f...guide recess, 12h...step, 12
i...protective wall, 13...magnetic pole plate.

Claims (1)

[Claims for Utility Model Registration] 1. A pair of stationary contacts facing each other with a distance therebetween, and the stationary contact supported by an interlocking rod that is supported so as to be able to reciprocate between the opposed stationary contacts. an arc-extinguishing chamber having a movable contact that bridges the terminals, an electromagnet that drives the interlocking rod and controls the contact and separation between the fixed contact and the movable contact, and a permanent magnet with a polarity perpendicular to the current direction. In a DC electromagnetic contactor, the arc extinguishing chamber is formed by an upper cover molded from a thermoplastic resin, a permanent magnet molded from a thermosetting resin and having a polarity perpendicular to the current direction, and two magnetic poles that are attracted to the permanent magnet. A DC electromagnetic contact comprising an arc shielding block to which a plate is attached, and the arc shielding block is engaged with a locking hook provided on the upper cover to integrate the arc shielding block and the upper cover. vessel. 2 Utility Model Registration Scope of Claim In the DC electromagnetic contactor described in claim 1, the arc shielding block has a stepped portion that engages with the locking hook of the upper cover and a square window bored in the locking hook portion of the upper cover. A DC electromagnetic contactor characterized by having a fitting protrusion. 3 Utility Model Registration Scope of Claims In the DC electromagnetic contactor according to claim 1 or 2, the arc shielding block has a U-shaped groove in which the permanent magnet is set on the front side thereof, and has a U-shaped groove on the outside of both side partition walls. A DC electromagnetic contactor characterized by having a guide recess for guiding a magnetic pole plate. 4 Utility Model Registration Scope of Claims In the DC electromagnetic contactor according to claims 1 to 3, the arc shielding block has a gas vent hole on the front side perpendicular to the energization direction, and the back side is bent to form the fixed contact. A DC electromagnetic contactor characterized by having a side wall that covers a mounting portion of a child.