JPH0636635A - Contact opening/closing device - Google Patents

Abstract

PURPOSE:To open and close contacts at enhanced weld resistance by pressing the movable contact of a movable contact arm against the fixed contact of a fixed contact arm energized by a spring and having a stopper for regulating the retreat position thereof. CONSTITUTION:A movable contact arm 1 made by a conductive plate spring is secured to a terminal assembly 6 at one end and is moved via the card 11 of a drive means 3 so that a movable contact 5 provided at the other end of the arm 1 is connected to and disconnected from an opposite fixed contact 8 thereby opening and closing the contacts. In the contact switching device, the fixed contact 8 is mounted on the upper end of a fixed contact 2 made by a conductive plate spring having its end secured to a terminal assembly 9, and is energized toward the movable contact 5. A stopper 4 for regulating the retreat position of the fixed contact arm 2 when the fixed contact 8 is pressed via the movable contact 5 is formed at the upper end portion of the terminal assembly 9. A regulating portion 14 provided at the curved upper end portion 13 of the stopper 4 is engaged in the lock recessed upper end portion 19 of the fixed contact arm 2 so as to regulate the distance (d) by which the fixed contact arm 2 can be moved from the stopper 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact switching device applied to an electromagnetic relay or the like.

[0002]

2. Description of the Related Art A conventional example is shown in FIGS. That is, this contact opening / closing device includes a movable contact 51 having a movable contact 50, a fixed contact 52 facing the movable contact 50,
The movable contact 51 is provided with a drive means 53 that drives the movable contact 51 so that the movable contact 51 comes into contact with and separates from the fixed contact 52.

This contact switchgear is in the state shown in FIG.
The movable contact 51 is driven by the driving means 53 from
Move the movable contact 50 to the fixed contact 52 as shown in Fig. (B).
Then, further bend the movable contactor 51 as shown in FIG.
Contact pressure is applied to the movable contact 50. Figure 8 shows the movable contact
Spring load for stroke 51, A₀Figure 7
As shown in (b) of FIG.
It is the position. Figure 9 shows position A ₀Contact pressure is 0 up to
But position A₀The movable contact increases linearly as shown in the figure.
The contact pressure at point 50 is shown.

[0004]

When a load such as a capacitor load in which a large current flows immediately after the contact is opened is opened and closed, there is a problem of contact welding. The following is known about the phenomenon immediately after the contact is closed. That is,
(1) Before the mechanical contact of the contacts, discharge starts between the contacts and an arc is generated. (2) A repulsive force acts between the contacts due to the arc or current. (3) The fused portion of the contact surface caused by the arc is fixed within several tens of μsec after the arc is stopped. Therefore, the larger the current value immediately before the mechanical contact, the larger the fusion area and the greater the welding force. (4) The greater the contact pressure at the time of mechanical contact, the greater the welding force.

Therefore, the smaller the current value at the time of contact with the contact and the smaller the contact pressure, the smaller the welding force, and the more the welding resistance can be improved. Therefore, an object of the present invention is to provide a contact switchgear capable of improving welding resistance.

[0006]

A contact opening / closing device according to claim 1 has a movable contact having a movable contact and a fixed contact facing the movable contact, and is biased by a spring in a direction approaching the movable contact. Fixed contactor, driving means for driving the movable contactor so that the movable contact is brought into contact with and separated from the fixed contact, and the fixed contactor is arranged on the opposite side of the fixed contact with a space. And a stopper that regulates the retracted position of the fixed contact pressed by the movable contact via the fixed contact.

According to a second aspect of the present invention, there is provided a contact opening / closing device according to the first aspect, which has a restricting portion which is locked to the front side of the fixed contact to set the distance between the fixed contact and the stopper.

[0008]

According to the contact opening / closing device of the present invention, the movable contact is brought into contact with the fixed contact by driving the movable contact by the drive means, and the movable contact is further pressed by the drive means, whereby the movable contact and the fixed contact. The fixed contact is pressed against the spring through the contact, and the contact pressure is applied by the pressing force of the driving means in a state where the fixed contact is locked to the stopper.

In this case, since the fixed contact is biased by the spring to a position away from the stopper, an arc is generated immediately before the contact between the movable contact and the fixed contact, and a repulsive force is generated between the movable contact and the fixed contact. When occurs, the fixed contact can be elastically retracted by the spring, so the contact time becomes longer,
The inrush current can be brought into contact with each other in a state of being sufficiently small, whereby the welding force can be suppressed small. Even when the movable contact contacts the fixed contact when the inrush current is large, the welding pressure is small because the contact pressure is small until the fixed contact is locked by the stopper. Therefore, the welding resistance can be improved.

According to a second aspect of the present invention, there is provided the contact opening / closing device according to the first aspect, which has a restricting portion which is locked to the front side of the fixed contact to set the gap of the fixed contact from the stopper. In addition to the effect of the first aspect, the stroke of the fixed contactor due to the spring is stabilized, and the time from the start of contacting the contact until obtaining the normal contact pressure can be stabilized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. That is, this contact opening / closing device includes a movable contact 1, a fixed contact 2, a drive unit 3, and a stopper 4.
Have and. The movable contact 1 has a movable contact 5. The movable contactor 1 of the embodiment uses a conductive leaf spring. The hole 18 at one end is fitted into the caulking protrusion 7 of the terminal plate 6 and caulked and fixed, and the hole 17 at the tip portion is caulked with the movable contact 5. Are fitted and fixed.

The fixed contactor 2 has a fixed contact 8 facing the movable contact 5, and is biased by a spring in a direction toward the movable contact 5. As the fixed contactor 2 of the embodiment, a conductive leaf spring having a spring constant sufficiently smaller than that of the movable contactor 1 is used, and the caulking hole 16 at one end is provided with the caulking protrusion 10 at the intermediate portion of the terminal plate 9.
The caulked portion is fixed by caulking, and the base end portion is bent in an inclined state so as to float above the terminal plate 9, and the caulked portion of the fixed contact 8 is fitted and caulked and fixed in the hole 15 at the tip portion. Further, a locking recess 19 is formed at the tip edge.

The driving means 3 drives the movable contact 1 so that the movable contact 5 comes into contact with and separates from the fixed contact 8. The drive means 3 of the embodiment uses an electromagnet (not shown), and the card 11 connected to the movable part of the electromagnet faces the intermediate part of the movable contact 1. The stopper 4 is arranged on the opposite side of the fixed contact 8 of the fixed contact 2 at a distance and regulates the retracted position of the fixed contact 2 which is pressed by the movable contact 5 via the fixed contact 8. The stopper 4 of the embodiment also serves as the tip portion of the terminal plate 9, and has an escape hole 12 for escaping the caulked portion of the fixed contact 8. Further, a bent portion 13 that fits into the locking recess 19 is provided at the tip of the terminal plate 9, and a restricting portion 14 that is locked to the front surface of the fixed contact 2 is provided at the tip of the bent portion 13. Due to the setting of the restriction portion 14, the movable distance d between the stopper 4 of the fixed contactor 2 and the restriction portion 14 is set to about several hundred μ.

According to this embodiment, the movable contact 1 is driven by the driving means 3 to bring the movable contact 5 into contact with the fixed contact 8 as shown in FIGS. At this time, the arc duration can be controlled by the movable distance d of the fixed contactor 2 and the contact closing speed, and it is possible to prevent unnecessary contact wear due to the arc being treated only for the rush current and the arc duration being too long.

Further, the movable contact 1 is pressed by the driving means 3 to move the movable contact 5 as shown in FIGS.
Presses the fixed contact 2 through the fixed contact 8 against its own spring force, so that contact pressure is generated.
Has a small spring constant, and the contact pressure is kept from a few grams to a dozen grams. As shown in FIG. 4D, the normal contact pressure is applied by the pressing force of the driving means 3 in the state where the fixed contactor 2 is locked to the stopper 4.

FIG. 3 shows the relation of the spring load with respect to the stroke of the movable contact 1, and FIG. 4 shows the relation of the contact pressure with respect to the stroke of the movable contact 1. In the figure, t ₀ is the contact opening position of the movable contact 1, t ₁ is the contact contact position of FIG. 2B, and t ₂ is the position where the fixed contact 2 of FIG. . In this case, since the fixed contactor 2 is biased to a position away from the stopper 4 by its own spring force, an arc is generated immediately before the contact between the movable contact 5 and the fixed contact 8 and an arc is generated. When a repulsive force is generated between the movable contact 5 and the fixed contact 2, the fixed contact 2 can be elastically retracted by its own spring force, so that the contact time of the movable contact 5 becomes long and the inrush current is sufficiently reduced. It is possible to suppress the welding force. Even when the movable contact 5 contacts the fixed contact 8 when the inrush current is large, the welding pressure is small because the contact pressure is small until the fixed contact 2 is locked by the stopper 4. Therefore, the welding resistance can be improved.

Further, since the fixed contactor 2 has the regulating portion 14 which is locked to the front side to set the movable distance d of the fixed contactor 2 from the stopper 4, the stroke of the fixed contactor 2 by the spring is stabilized, It is possible to stabilize the time from the start of contact contact until the normal contact pressure is obtained. Further, in the conventional example, the present invention can be achieved by the structure in which the fixed contact 2 is biased by the spring, so that the structure is simple.

A second embodiment of the present invention is shown in FIG. That is, in this contact opening / closing device, the movable contact 1 is formed of a rigid strip plate, and a fulcrum portion 20 is provided on the base end of the movable contact 1 on the side opposite to the movable contact 5, and is supported by a spring support 21. The base end of the movable contact 1 is pressed in the opening direction by the tip of the spring 22, which is a coil spring as an example. In this embodiment, the movable contact 1 is urged by the spring 22 in the opening direction to press the card 11 of the driving means 3 against the opening position of the movable contact 1 by using the fulcrum portion 20 as a fulcrum to drive the moving contact 1. Card 1 with 3
The movable contact 1 is resisted against the spring 22 by driving 1
When is pressed, the movable contact 1 rotates about the fulcrum 20 as a fulcrum, and the movable contact 5 contacts the fixed contact 8. When it is further pressed, the fixed contact 2 is bent and locked by the stopper 4. When it is further pressed, the movable contact 1 rotates about the fixed contact 8 as a fulcrum to compress the spring 22, and a contact pressure is applied to the movable contact 5 by this reaction. Therefore, the graph for the stroke of the spring load and the contact pressure is the same as that of the first embodiment. Other than that, the same effect as the first embodiment is obtained.

The contact opening / closing device can also be applied to a contact mechanism having an arc contact.

[0020]

According to the contact opening / closing device of the present invention, since the fixed contact is biased by the spring to a position away from the stopper, an arc is generated immediately before the contact between the movable contact and the fixed contact and the movable contact is moved. When repulsive force is generated between the contact and the fixed contact,
Since the fixed contact can be elastically retracted by the spring, the contact time becomes longer, and the contact can be made in a state where the inrush current is sufficiently small, whereby the welding force can be suppressed to be small. Even when the movable contact contacts the fixed contact when the inrush current is large, the welding pressure is small because the contact pressure is small until the fixed contact is locked by the stopper. Therefore, there is an effect that the welding resistance can be improved.

According to a second aspect of the present invention, there is provided the contact opening / closing device according to the first aspect, which has a restricting portion which is locked to the front side of the fixed contact to set the gap of the fixed contact from the stopper. In addition to the effect of the first aspect, the stroke of the fixed contactor due to the spring is stabilized, and the time from the start of contacting the contact until obtaining the normal contact pressure can be stabilized.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of the operation.

FIG. 3 is a graph of a spring load line with respect to a stroke of a movable contactor.

FIG. 4 is a graph of contact pressure with respect to a stroke of a movable contactor.

FIG. 5 is an exploded perspective view.

FIG. 6 is a perspective view of a second embodiment.

FIG. 7 is an operation explanatory diagram of a conventional example.

FIG. 8 is a graph of a spring load line with respect to the stroke of the movable contactor.

FIG. 9 is a graph of contact pressure versus stroke of a movable contactor.

[Explanation of symbols]

 1 moving contact 2 fixed contact 3 driving means 4 stopper 5 moving contact 8 fixed contact

Claims (2)

[Claims] 1. A movable contact having a movable contact, a fixed contact having a fixed contact facing the movable contact and biased by a spring in a direction of approaching the movable contact, and the movable contact fixed the movable contact. Driving means for driving the movable contactor so as to come into contact with and separate from the contact point, and a driving element which is arranged on the opposite side of the fixed contact point from the fixed contact point with a gap and is pressed by the movable contact point through the fixed contact point. A contact opening / closing device comprising a stopper that regulates the retracted position of the fixed contact. 2. The contact opening / closing device according to claim 1, further comprising a restricting portion that is locked to a front side of the fixed contact to set the distance between the fixed contact and the stopper.