JPH0636636A - Contact opening/closing device - Google Patents

Abstract

PURPOSE:To enhance weld resisting performance and reduce sounds caused by the collision of an electromagnet mounted to a movable frame for driving movable contact plates by providing the electromagnet with a magnetic damper which is held by a permanent magnet and moved against the holding force, together with an armature. CONSTITUTION:A pair 10 of contacts comprising a fixed 11 and movable 12 contact of good weld resisting performance and a pair 20 of contacts having good contact resisting performance are connected in parallel to each other and are assembled into a block B via contact plates 13, 14, 23, 24. The movable contact plates 14, 24 are operated via a movable frame 8 to connect and disconnect the contacts 11, 12, 21, 22. The movable frame 8 is operated by an electromagnet E comprising a coil 4 wound to an iron core 3, and by a permanent magnet 7 of magnetic force opposite to that of the electromagnet E. In the contact switching device, a magnetic damper 9 of a U-cross section is provided which is loosely fitted into the broad part 3C of the iron core 3 and is held by the magnetic force of the permanent magnet 7 and moved together with the magnet. The weld resisting performance of the pairs 10, 20 of contacts is thereby enhanced and sounds caused by the collision of the electromagnet E during the switching operation are reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact switchgear for opening and closing a load having a large inrush current such as a capacitor load or a lamp load, and more particularly to a contact switchgear suitable for an electromagnetic relay opening and closing such a load.

[0002]

2. Description of the Related Art Generally, a contact opening / closing device used in an electromagnetic relay performs a contact opening / closing operation by driving a movable contact plate provided with a movable contact which comes in contact with and separates from a fixed contact by an electromagnet.

By the way, when a capacitor load, a lamp load, etc. are opened and closed, a large rush current flows, and the arc generated thereby sometimes causes contact welding. In order to prevent this, it is conceivable to use, as the contact material, a material having good welding resistance such as tungsten. However, in this case, since a material such as tungsten has a large resistance value, the temperature rise in the contact closed state becomes large.

Therefore, a contact pair having a good welding resistance and a contact pair having a good contact resistance are in parallel connection, and the contact plates provided with the movable contacts are movable members of the electromagnet. That is, a contact pair that is driven by a movable frame holding an armature and has good welding resistance contacts first during contact closing operation, and then separates after contact opening operation. A contact switchgear in which a good contact pair is in contact has been proposed (for example, JP-B-51-23863, JP-B-55-42341, JP-A-61-
233919, JP-A-62-71137, JP-A-62-71138, etc.).

[0005]

In the above contact switching device, there is a difference in the closing time from when a contact pair having good welding resistance is made and then a contact pair having good contact resistance is made next. I can't get too big.

That is, FIG. 11 shows a characteristic diagram of the load (load) of the spring (movable contact plate) and the attraction force when the above-mentioned contact switching device is driven by a bistable electromagnet. In the figure,
The horizontal axis is the stroke of the movable member of the electromagnet, the vertical axis is the spring load and the attraction force, FB is the spring load, FS is the attraction force when set (closed), FR is the attraction force when reset (cut off), and F0 is non-excitation. When it is suction power. As is clear from Fig. 11, the spring load at the time of setting increases at the stroke x1 with the contact pair with good welding resistance being turned on, and at the stroke x2 with the contact pair having good contact resistance being turned on. Further increase.

The operating characteristics of the contacts are as shown in FIG. In the figure, the horizontal axis represents time, and the vertical axis represents the displacement M of the movable member of the electromagnet and its velocity V. As is clear from FIG. 12, the contact pair with good welding resistance is turned on at time t1, and the contact pair with good contact resistance is turned on at time t2. The displacement (stroke) difference Δx _2-1 from when a contact pair with good welding resistance is turned on until the next contact pair with good contact resistance is turned on is originally small (see Fig. 11),
Moreover, since the velocity V of the movable member of the electromagnet is sufficiently high, the time difference Δt _2-1 between the closing of a contact pair with good welding resistance and the next contact with good contact resistance performance Cannot be so large. As a result, there is a risk that a contact pair having good contact resistance performance may be turned on when an inrush current is flowing, and in such a case, contact welding will occur.

Further, since the velocity V of the movable member of the electromagnet, that is, the movable frame holding the armature is high, the collision noise when the magnetic member collides with the magnetic member, for example, the magnetic pole surface of the fixed iron core, becomes large.

In FIG. 12, Ca represents the open / closed state of the contact pair having a good welding resistance, Cb represents the open / closed state of the contact pair having a good contact resistance performance, and Ip represents the inrush current.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a contact opening / closing device capable of further improving the welding resistance and reducing the collision noise of an electromagnet.

[0011]

In order to solve such a problem, a contact opening / closing device of the present invention has a magnetic member having a magnetic pole surface wound with a coil and an armature attracted to and separated from the magnetic pole surface. It has an electromagnet with an armature, a movable frame that holds the armature, and a permanent magnet that is inserted in the magnetic circuit that includes the magnetic member and the armature, and has a good contact resistance with good welding resistance and good contact resistance. In a contact switching device in which a movable contact plate provided with movable contact points is driven by a movable frame of an electromagnet, the electromagnet is in contact with the magnetic pole surface. It is held between the poles by the magnetic force of the permanent magnet, and is moved by the armature against the holding force of the permanent magnet when the armature is attracted to the magnetic pole surface, and when it is moved, the armature. And porcelain It has a configuration in which a magnetic cushion that does not inhibit the contact surface.

[0012]

According to this structure, the operation speed of the armature of the electromagnet is reduced by moving the magnetic buffer held by the magnetic force of the permanent magnet, and therefore the contact pair having good welding resistance is turned on and In addition, the closing time difference Δt _2-1 until a contact pair having good contact resistance performance is closed can be made large, and the collision noise when the magnetic pole surface of the armature fixed iron core collides is reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to an electromagnetic relay will be described below with reference to FIGS.

B is a base of the electromagnetic relay R, and a contact switchgear described later, that is, the electromagnet E, the contact pair 10 having good welding resistance and the contact pair 20 having good contact resistance are attached and arranged. is doing. C is a case that forms a housing together with the base B.

This electromagnet E is a movable frame for holding a magnetic member 1 wound with a coil 4 and an armature 6 including a permanent magnet 7.
8 and the magnetic buffer 9 are the main constituent members.

The magnetic member 1 comprises a yoke 2 and a fixed iron core 3. The yoke 2 includes a flat plate-shaped base piece 2a, a fixed piece 2b formed by bending one end thereof at a substantially right angle, and opposite leg pieces 2c, 2c formed by bending both side portions on the other end side at a substantially right angle. Have. Fixed iron core
Numeral 3 is made of a magnetic plate material, and the narrow portion 3a and the wide portion 3c are substantially T
It has a character shape, and the wide portion 3c serves as a magnetic pole surface for an armature described later. The wide width portion (magnetic pole surface) 3c has a buffer body recess 3 formed by cutting both front end sides to a predetermined depth.
d, 3d are formed. A magnetic buffer, which will be described later, is located in the buffer body recesses 3d, 3d.

The coil 4 is wound around the coil frame 5, and the narrow portion 3a of the fixed iron core 3 is inserted into the inner hole 5a of the coil frame 5. Coil frame 5 has collar parts at both ends of the winding drum part with inner hole 5a.
It has 5b and 5c. One of the collars 5b has coil terminals 4a, 4a, 4
A shaft portion 5d is formed on the upper end face of the movable frame, which is a fulcrum of rotation of the movable frame as will be described later, while holding a through.

In the magnetic member 1, the end of the narrow portion 3a of the fixed iron core 3 which is inserted into the inner hole 5a of the coil frame 5 is fixed to the fixing piece 2b of the yoke 2.
It is assembled by fixing to.

The armature 6 has a U-shaped movable frame composed of two armatures 6c, 6c and a permanent magnet 7 sandwiched between them.
Holds at 8. The movable frame 8 is made of resin and has a fixed iron core.
3 has a base 8a corresponding to the length of 3 and coil frame 5
A bearing portion 8d fitted to the shaft portion 5d, drive portions 8b and 8c for driving the contact plate on both sides of the intermediate portion, and a holding portion 8e for holding the armature 6 on the other end side are formed. One of the drive parts 8b has a lift-off type first drive part P1 and a flexure type second drive part P1 with respect to a movable contact plate of a contact pair 10 having good welding resistance, which will be described later.
The drive unit P2 is provided so as to face the movable contact plate with a predetermined gap therebetween. The other drive unit 8c faces the movable contact plate of the contact pair 20 having good contact resistance performance, which will be described later. Therefore, when the bearing part 8d of the movable frame 8 is fitted to the shaft part 5d of the coil frame 5, the contact points 10 and 20 are as described above, and the inner surfaces of the armatures 6c and 6c of the armature 6 are Fixed iron core 3
Of the armature 6c, 6c is opposed to the wide portion (pole surface) 3c of the coil and the excitation of the coil 4 is controlled so that the armatures 6c and 6c are attracted and separated from the wide portion (pole surface) 3c.

As shown in FIG. 4, the magnetic buffer body 9 is made of a magnetic plate material, and is formed in a U-shape by the facing pieces 9c, 9c and the connecting piece 9a. The relationship between the thickness of the magnetic buffer 9 and the depth of the buffer recesses 3d, 3d is important, and the depth of the buffer recesses 3d, 3d should be equal to or greater than the thickness of the magnetic buffer 9. To Also, the opposing pieces 9c, 9c are larger than the thickness of the wide portion (pole surface) 3c sandwiched between the buffer recesses 3d, 3d, and the outer method is between the armatures 6c, 6c of the armature 6. Set smaller.
In the magnetic buffer body 9, one of the facing pieces 9c is held between the magnetic pole surface 3c and the armature 6c by the magnetic force of the permanent magnet 7.

Such an electromagnet E has coil terminals 4a, 4a,
The 4a is fixed to the base B by penetrating it so that it is attached to the approximate center thereof.

The contact pair 10 having good welding resistance is composed of a fixed contact 11 and a movable contact formed of a material such as tungsten.
Consists of 12. The fixed contact 11 is fixed to a fixed contact terminal 13, and the fixed contact terminal 13 is fixed through the base B. The movable contact 12 has a movable contact plate 14 fixed to the movable contact terminal 15.
The movable contact terminal 15 is also fixed to the base B through.

The contact pair 10 is of a lift-off type when the contact is opened (opening), and is the first drive portion P1 of the drive portion 8b.
It is driven by the second drive unit P2 of the drive unit 8b in a flexure type during contact closing (closing) operation.

The contact pair 20 having good contact resistance performance is composed of a fixed contact 21 and a movable contact 22 formed of a material such as a silver alloy. The fixed contact 21 is fixed to a fixed contact terminal 23, and the fixed contact terminal 23 is fixed through the base B. Moving contact
22 is fixed to a movable contact plate 24 fixed to a movable contact terminal 25, and this movable contact terminal 25 is also fixed to the base B through.

This contact pair 20 is of a flexure type, that is, a normally open type, and is in an open state when it is not pressed by the other drive portion 8c. The other drive unit 8c of this embodiment is also shaped to sandwich the movable contact plate 24 with a gap therebetween and has a lift-off type function, but this is not an essential condition.

The two contact pairs 10 and 20 are connected in parallel, and the movable contact plate 1 having the movable contacts 12 and 22 is provided.
The contact pairs 10 and 4, 24, which are driven by the electromagnet E and have good welding resistance, are set to come into contact first during the contact closing operation and to open after the contact opening operation.

The operation of the magnetic buffer 9 of the electromagnet E in the contact switching device will be described with reference to FIGS. 5 (a) to 5 (c) showing the operation of the armature 6. (a) is a state in which the armature 6c on the left side of the armature 6 is attracted to the magnetic pole surface 3c of the fixed iron core 3. In this case, even if the coil 4 is not excited, that state is maintained by the magnetic force of the permanent magnet 7.
Further, in the magnetic buffer 9, the left facing piece 9c is located in the buffer recess 3d on the left and is also held by the magnetic force of the permanent magnet. The left facing piece 9c is interposed between the left armature 6c and the magnetic pole surface 3c of the fixed iron core 3, but does not hinder the direct contact between the armature 6c and the magnetic pole surface 3c.

In this state, the permanent magnet flowing through the fixed iron core 3
When the coil 4 is excited to flow the magnetic flux in the direction of canceling the magnetic flux of 7, the magnetic flux by the coil 4 also flows to the right armature 6c and attracts it, and the armature 6 starts moving in the arrow direction. Then, as shown in (b), the right armature 6c comes into contact with the right facing piece 9c. Therefore, Amatya 6 is a permanent magnet 7
The magnetic buffer body 9 held by the holding force of is moved while moving against the holding force, and as shown in (c), the armature 6c on the right side contacts the magnetic pole surface 3c of the fixed iron core 3. Sucked.

Even when the coil 4 is no longer excited in the state of (c), the state of the armature 6 is maintained by the magnetic force of the permanent magnet 7, and the magnetic buffer body 9 has the right facing piece 9c for buffering the right side. It is located inside the body recess 3d and is also held by the magnetic force of the permanent magnet. The right facing piece 9c is interposed between the right armature 6c and the magnetic pole surface 3c of the fixed iron core 3, but does not hinder the direct contact between the armature 6c and the magnetic pole surface 3c.

Therefore, each movable contact plate 14, 2 of each contact pair 10, 20
4 is a movable frame 8 holding an armature 6 including a permanent magnet 7.
It is driven by the drive units 8b and 8c of the above to perform the contact opening / closing operation.
Since the moving speed of the armature 6 in such an operation is reduced and it collides with the magnetic pole surface 3c, a contact pair with good welding resistance is turned on, and then a contact pair with good contact resistance is turned on. The difference Δt _{2-1 in} the charging time until the start of the collision can be made large, and the collision noise at that time can be reduced.

In other words, the magnetic buffer 9 is moved by the armature against the holding force of the permanent magnet when the armature is attracted to the magnetic pole surface, and when it is moved, the armature and the magnetic pole surface. It does not interfere with the contact of the. This means that, in addition to the above-mentioned action, compared to a fixed core with a cushioning member attached to reduce collision noise,
This brings about the effect that the original total stroke in the attraction force characteristic diagram does not decrease and each attraction force for holding the armature does not become small.

In order to move the armature 6 in the reverse direction from the state of (c), it suffices to excite the coil 4 so that the magnetic flux in the opposite direction to that in the previous case flows, and the case where the magnetic buffer 9 is the previous case. By the same action, Amatya 4 returns to the state of (a).

More specifically, when the operating characteristics of the contacts and the like are compared with those of the conventional example shown in FIG. 12, it becomes as shown in FIG. In the figure, the horizontal axis represents time, and the vertical axis represents the displacement M of the movable member of the electromagnet E and its velocity V. As is apparent from FIG. 6, the contact pair 10 having good welding resistance is turned on at the time t1, and the armature 6c abuts on the magnetic buffer 9 at the time t2.
Then, at time t3, the contact pair 20 having good contact resistance performance is turned on. Therefore, the displacement (stroke) difference between the contact pair 10 with good welding resistance performance and the contact pair 20 with good contact resistance performance next is larger than that of the conventional one. Since the velocity V of the movable member of is small,
As described above, the difference Δt _2-1 in making time from when the contact pair 10 having good welding resistance performance is made until the contact pair 20 having good contact resistance performance is made next can be made large. As a result, reduced extremely danger of contact resistance good contact pair of potential 20 is turned on when the inrush current is flowing, contact welding is less likely to occur. Naturally, the collision noise of Amatya 6 is also reduced.

In FIG. 6, Ca represents the open / closed state of the contact pair having good welding resistance, Cb represents the open / closed state of the contact pair having good contact resistance, and Ip represents the inrush current. Further, (a), (b) and (c) in the curve of the displacement M of the movable member correspond to those in FIG.

FIG. 7 shows a modification of the magnetic buffer 9 and the magnetic pole surface 3c of the fixed iron core 3. This one is the recess for buffer 3d, 3d
A wide recess (pole face) 3c sandwiched between
3e is provided, and the connecting piece 9a of the magnetic buffer 9 is narrowed so as to be located in the through recess 3e. This is a fixed iron core
The length of the electromagnet device corresponding to the longitudinal direction of 3 can be shortened,
Moreover, the magnetic buffer 9 can be held more reliably.

FIG. 8 shows another modified example. This is because the buffer recesses 3d and 3d are formed on one side of the wide part (pole face) 3c.
It is provided only on the upper side (in the figure), and a through recess 3e is further provided in the center thereof, and the narrow connecting piece 9a of the magnetic buffer 9 is located in the through recess 3e.

FIG. 9 shows another modification as well.
This is because the recesses 3d, 3d for the buffer body are formed in the wide part (pole face) 3c.
Is provided in the center of the magnetic buffer body 9 and a through hole 3f is further provided in the center of the magnetic buffer body 9. The connecting piece 9a of the magnetic buffer 9 is formed into a stepped round bar to penetrate the through hole 3f, and the facing pieces 9c and 9c are caulked and fixed. In this case, the holding of the magnetic buffer 9 becomes more reliable than in the above-described modification.

FIG. 10 shows the magnetic buffer 9 of FIG. 7 or 8.
In this modified example, the two opposing pieces 9c and 9c made of a magnetic plate material and the connecting piece 9a made of a non-magnetic plate material are separately formed and integrated later.

In the embodiment or the modification, the permanent magnet is described as a member forming an armature, but it may be inserted in a magnetic member, that is, a yoke or a fixed iron core. Further, the shape of the magnetic buffer body, the structure for holding the magnetic buffer body, and the like can be appropriately changed. Further, the contact opening / closing device of the present invention can of course be applied to various types of electromagnetic relays.

[0040]

According to the contact opening / closing device of the present invention, the operating speed of the armature of the electromagnet is reduced by moving the magnetic buffer held by the magnetic force of the permanent magnet. The time difference Δt _2-1 between when the contact pair is turned on and when the contact pair with good contact resistance performance is turned on is large, and the welding resistance performance is further improved.
Collision noise when colliding with the magnetic pole surface of the stationary armature is also reduced

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention applied to an electromagnetic relay.

FIG. 2 is a plan view thereof.

FIG. 3 is a perspective view thereof.

FIG. 4 is an exploded perspective view of a main part thereof.

5 (a) to 5 (c) are diagrams for explaining the operation of the armature.

FIG. 6 is an operation characteristic diagram of contacts and the like.

FIG. 7 is an exploded perspective view of essential parts showing a modified example of the magnetic buffer body and the fixed iron core.

FIG. 8 is an exploded perspective view of an essential part showing another modification thereof.

FIG. 9 is an exploded perspective view of an essential part showing still another modification thereof.

FIG. 10 is a perspective view showing a modified example of the magnetic buffer body.

FIG. 11 is a suction force characteristic diagram of a conventional example.

FIG. 12 is an operational characteristic diagram of the contacts and the like.

[Explanation of symbols]

 1 Magnetic member 2 Yoke 3 Fixed iron core 3c Wide part (pole surface) 3d Buffer recess 4 Coil 5 Coil frame 6 Armature 6c Armature armature 7 Permanent magnet 8 Movable frame 9 Magnetic buffer 9a Magnetic buffer connecting piece 9c Opposite piece of magnetic buffer 10 Contact pair with good welding resistance 11 Fixed contact of contact pair with good welding resistance 12 Movable contact of contact pair with good welding resistance 20 Contact pair contact with good contact resistance 21 Contact with good contact resistance performance Fixed contact with contact 22 Movable contact with contact good contact resistance with contact E Electromagnetic device R Electromagnetic relay B Base of electromagnetic relay

Claims (1)

[Claims] 1. A magnetic member that winds a coil and has a magnetic pole surface, an armature having an armature that attracts and separates from the magnetic pole surface, a movable frame that holds the armature, and a magnetic circuit including the magnetic member and the armature. An electromagnet having a permanent magnet and a contact pair having good welding resistance and a contact resistance having good contact resistance. In a contact switching device in which a movable contact plate provided with side contacts is driven by a movable frame of an electromagnet, the electromagnet is held by a magnetic force of a permanent magnet between the magnetic pole surface and the armature, and the armature is A magnetic buffer is provided that is moved by the armature against the holding force of the permanent magnet when attracted to the magnetic pole surface, and that does not hinder the contact between the armature and the magnetic pole surface when the armature is moved. Contact switching device Place