JPH0316169Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of an electromagnetic contactor equipped with an arc extinguishing mechanism.

Generally, this type of electromagnetic contactor is used to start and stop three-phase induction motors, etc., but recently it has been used as a control device for starting and stopping motors that drive automation and labor-saving devices. As the number of electric motors increases, there is a need for an electromagnetic contactor that can cope with inching operation in which the electric motor is frequently started and stopped.

1 to 5 show conventional devices of this type. In these figures, reference numeral 1 denotes a mounting base made of a metal steel plate, and the mounting base 1 is provided with a plurality of mounting holes 1a used when installing the electromagnetic contactor main body. Reference numeral 2 denotes a paste made of an insulating material, which is fixed to the mounting base 1 with screws 3. Reference numeral 4 denotes a fixed core made of laminated silicon steel plates.A control coil 5 is attached to the fixed core 4, and a leaf spring 6 is disposed at a distance from the mounting base 1 as a cushioning material. 7
is a movable core disposed facing the fixed core 4, and when the operating coil 5 is energized, the fixed core 4
It is designed to be absorbed by. A cross bar 8 is made of an insulating material and is connected to the movable iron core 7 via a pin 9. A trip spring 10 is disposed between the crossbar 8 and the mounting base 1, and normally pushes up the crossbar 8 so that the main circuit of the electromagnetic contactor is opened. 11
is a movable contactor having a contact point 11a, which is inserted into a holding hole 8a provided in the crossbar 8, and is pressurized by a pressure spring 12. 13 is a contact 18a opposite to the contact 11a of the movable contactor 11;
The fixed contact 13 is fixed to a terminal 15 with a screw 14, and the terminal 15 is fixed to the base 2 with screws 16 and 17. 18 is a terminal screw connected to the main circuit electric wire, and is provided in the terminal 15. An arc box 19 is made of an insulating material and is fixed to the base 2 with screws 20. The arc box 19 has a guide portion 19a of the cross bar 8, a ceiling portion 19b for preventing the arc from ejecting upward, and a side plate 19c for preventing the arc and hot gas from ejecting directly to the outside. Reference numeral 21 denotes an arc extinguishing grid with a V-shaped groove 21a in the center, a specified gap, a specified number of grids combined, and a case 22a made of insulating material.
22b' and attached to the arc box 19.

Next, the opening/closing operation of this electromagnetic contactor will be explained.

When a voltage is applied to the operating coil 5 in the state where the main circuit shown in FIG. The movable iron core 7 is attracted to the fixed iron core 4. At this time, the crossbar 8 connected to the movable iron core 7 also operates in the same manner, and the contact 11a of the movable contact 11 is connected to the contact 1 of the fixed contact 13.
3a, a predetermined pressure is applied by the pressure spring 12, and the main circuit is closed. Then, when the operating coil 5 is demagnetized, the tripping spring 1
The movable core 7 moves away from the fixed core 4 due to the urging force of 0, and the crossbar 8 also moves in conjunction with the movable core 7. Therefore, this cross bar 8 returns to the state shown in FIG.
a and are separated. At the time of this opening, the contact 11
An arc is generated between a and 13a at the part indicated by A in FIG. The arc is extinguished by the increase in arc voltage (due to the elongation of the arc positive column) due to the arc series gap between the extinguishing grids 21 (known as de-ion arc extinguishing).

Since the conventional electromagnetic contactor is constructed as described above, the arc generated between the contacts is not quickly magnetically driven to the arc-extinguishing grid 21, but remains stuck on the contact surface. As a result, the contact points were severely worn out, leading to problems such as the contact points peeling off or falling off.

The present invention was developed in order to eliminate the above-mentioned drawbacks of the conventional type. In order to quickly magnetically drive the arc generated between the contacts to the arc extinguishing grid, a protrusion is provided in the V-shaped groove of the arc extinguishing grid. By providing multiple contacts, the arc generated between the contacts is quickly magnetically driven to the arc-extinguishing grid, reducing contact wear and tear, preventing contacts from peeling off or falling off, and improving inching life, that is, electrical life. The purpose is to improve cutting performance.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 6, reference numeral 21 denotes an arc extinguishing grid having two protrusions at the base of a V-shaped groove 21a in the center, and cases 22a and 2 made of an insulating material.
2b and attached to the arc box 19.

Next, the operation of the electromagnetic contactor equipped with the arc extinguishing grid 21 shown in FIG. 6 from the closed state to the open state will be described. When the operating coil 5 is demagnetized, the movable core 7 separates from the fixed core 4 due to the biasing force of the tripping spring 10, and the crossbar 8 also moves in conjunction with the movable core 7. Therefore, crossbar 8
returns to its original state as shown in Figure 3, and
The contact 11a of the movable contact 11 and the contact 13a of the fixed contact 13 are separated. Upon this opening, an arc is generated between the contacts 11a and 13a at the part shown by A in FIG. The arc is driven to this point and is extinguished by increasing the arc voltage (by elongating the arc positive column) due to the arc series gap between the arc extinguishing grids 21 (known as de-ion arc extinguishing).

By the way, in the conventional device shown in FIG. 5, lines of magnetic force as shown by broken lines in FIG. 5 are generated near the arc 23 generated between the contacts, but the magnetic lines EFG,
Since E′F′G′ is long, the magnetic resistance in the gap increases, and the magnetic flux density at F and F′ becomes low. Therefore, since the magnetic driving force for the arc 23 is weak,
Since the arc 23 is not quickly driven to the arc-extinguishing grid 21 and remains stuck on the contact surface for a long time, the contact wears out rapidly and sometimes causes problems such as peeling or falling off of the contact.

In the present invention, in order to quickly magnetically drive the arc generated between the contacts to the arc extinguishing grid 21, the shape of the arc extinguishing grid 21 is changed to the V-shaped groove 21a of the arc extinguishing grid 21 as shown in FIG. By providing two or more protrusions, the arc generated between the contacts is quickly magnetically driven to the arc-extinguishing grid 21, reducing wear on the contacts, preventing them from peeling off or falling off, and improving inching life. It is possible to improve the shear cutting performance.

In the above embodiment, two protrusions are inserted into the V-shaped groove 21a of the arc extinguishing grid 21 as shown in FIG. The same effect can be obtained.

On the other hand, in the arc extinguishing grid 21 of the conventional device shown in FIG. 7a, if the position of the arc generated between the contacts is at point _P1 at the upper or lower end of the contacts, it is quickly driven in the direction B. If this generated arc occurs at point _P2 near the center of the contact, the A dimension with the arc extinguishing grid 21 is long, so this arc is difficult to be driven by the arc extinguishing grid 21 as shown in FIG. There was a drawback that the arc extinguishing grid 21 easily stuck to the innermost part 21b of the V-shaped groove 21a. Furthermore, in the arc extinguishing grid in the conventional device shown in FIG.
One protrusion is provided in the V-shaped groove 21a of the contact point 1, so that the arc generated near the center of the contact point is quickly driven to the arc extinguishing grid 21. But arc 2
The lines of magnetic force generated near point 3 are as shown by the broken lines in FIG. 8, and the magnetic paths EFG, E', F', and G' are long, so the magnetic resistance in the gap becomes large.

Therefore, since the magnetic flux density at F and F' is low and the magnetic drive is weak, the arc driven to the arc extinguishing grid 21 is difficult to be driven into the arc extinguishing grid 21 in the direction of arrow D in the figure, and the arc is extinguished. It had the disadvantage that it easily stuck to point _P3 of grid 21 and the arc time was long.

On the other hand, according to the arc extinguishing grid 21 in the electromagnetic contactor of the present invention shown in FIG. 7c, the arc 2
Since the lines of magnetic force near No. 3 are as shown by the broken lines in FIG. 6, the magnetic paths become short as EFG, E'F, and G, so the magnetic resistance in the gap becomes small. Therefore,
The magnetic flux density at F and F′ increases, and the arc 2
Since the magnetic driving force on the arc 23 is strong, the arc 23 is quickly driven to the arc extinguishing grid and is not stuck after reaching the grid.

Next, we will discuss the differences between Utility Model Application No. 51-107669 and this case. As shown in Figures 9a and 9b, there are notches 2 on the arc extinguishing grids 21 and 21' on the opposite side of the arc.
1a and 21'a are provided, and the position of the notch is changed between adjacent arc extinguishing grids.A groove is provided in the arc extinguishing grid and a protrusion is placed at the bottom of the groove. The structure is such that the arc extinguishing grids 21, 21' are stacked with different shapes, that is, the shapes of the arc extinguishing grids 21, 21' are changed for each laminated arc extinguishing grid.

With this configuration, the arc 23 between the contacts is formed in a zigzag shape until it contacts the arc extinguishing grids 21, 21'.

In other words, in the example shown in FIG. 9, by changing the arrangement of the magnetic material and forming the arc 23 in a zigzag shape, the length of the arc can be extended compared to the conventional arc, making it easier to extinguish the arc, thereby increasing the arc extinguishing ability. It is intended to improve The cited example shown in FIG. 9 discloses the effect of combining arc-extinguishing grids 21, 21' of different shapes to deform the arc and extend the length of the arc to increase the arc-extinguishing ability.

However, the arc 23 attracted to the arc extinguishing grids 21 and 21' is driven between the arc extinguishing grids while being deformed in a zigzag shape, so the arc 23 is driven, so the time for which the arc 23 is driven is long. Become.

On the other hand, in the present invention, the arc extinguishing grid 21 is
A V-shaped groove is provided, and a plurality of protrusions are provided at the base of this V-shaped groove, and the protrusions at the base are arranged so that they overlap, so that the arc is strongly magnetically driven as explained in Fig. 6. . Therefore, the arc is quickly driven to the arc extinguishing grid and is not stuck even when it reaches the arc extinguishing grid.

In this way, in the present invention, a plurality of protrusions are provided at the base of the V-shaped groove of the arc extinguishing grid, and the protrusions at the base are arranged so that they overlap, so that the arc can be generated at any position on the contact surface. This arc can be quickly driven to the arc-extinguishing grid even when the arc is in contact with the arc-extinguishing grid, and the arc cannot become stuck or stalled even after reaching the arc-extinguishing grid, reducing wear and tear on the contacts of the magnetic contactor. It is possible to prevent contacts from peeling off or falling off, extend inching life, and improve shearing performance. Further, the manufacture and arrangement of these parts are relatively simple, and the electromagnetic contactor device including them can be manufactured at low cost.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional magnetic contactor with each half cut away, Figure 2 is a bottom view of the right half of Figure 1, and Figure 3 is a right side view of the center of Figure 1. FIG. 4 is a perspective view of the assembly of the arc extinguishing grid in the conventional device shown in FIG. 1, FIG. 5 is a peripheral view of the arc extinguishing grid shown in FIG. 4, and FIG. A peripheral view of the arc extinguishing grid, Fig. 7 is an explanatory diagram of the effect of the present invention, Fig. 8 is an explanatory diagram of the operation in the conventional electromagnetic contactor shown in Fig. 7b, and Fig. 9 is an arc extinguishing diagram in the conventional electromagnetic contactor. FIG. 3 is a diagram showing the arrangement of grids. In the figure, 8 is a crossbar, 8a is a holding hole of the crossbar, 11 is a movable contact, 11a is a contact of the movable contact, 13 is a fixed contact, 13a is a contact of the fixed contact, 19 is an arc box, 21 21a is the V-shaped groove of the arc extinguishing grid 21, 22a and 22b are the cases, and 23 is the arc. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An electromagnetic contactor comprising a movable contact having a contact, a fixed contact having a contact, and an arc extinguishing grid disposed inside an arc box so as to face these contacts. A V-shaped groove that expands toward the contact side is provided, a plurality of projections are provided at the base of this V-shaped groove, and a plurality of arc extinguishing grids are arranged at intervals so that the positions of the projections overlap. An electromagnetic contactor featuring: