JP2640576B2 - Electromagnetic contactor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic contactor, and more particularly to an electromagnetic contactor capable of maintaining electrical performance at a contact for a long time.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view showing the entire mechanism of a conventional electromagnetic contactor, FIG. 3 is a sectional view taken along the line III--III of FIG. 2, and FIG. It is sectional drawing.
In the figure, reference numeral 1 denotes a three-pole first movable contact arranged at an interval so as to energize a load such as a motor from a three-phase power supply, and two are provided at both ends of each first movable contact 1. The movable contact 3 is a pressing spring that urges the first movable contact 1 in a fixed direction within a range that does not restrict the movement of the first movable contact 1, and 4 is a three-pole first movable contact 1 that is fixed to each other via the pressing spring 3. The contact support frame 4a made of a synthetic resin for supporting the first movable contactors 1 in the same direction and supporting the first movable contact 1 in the same direction, 4a is a fulcrum for receiving a driving force of an electromagnet described later in the contact support frame 4, and 5 is Each first
A first fixed contact that has a fixed contact 6 facing the movable contact 2 of the movable contact 1 and is disposed on both sides of the contact support frame 4;
Reference numeral 7 denotes a second movable contact added for control separately from energization of a load such as a motor, 8 denotes a second fixed contact facing the second movable contact 7, and 9 denotes a first fixed contact. An upper case for accommodating the contact support frame 4, an electromagnet 10 serving as a drive source of the fulcrum support frame 4, and a link 11 for transmitting the driving force of the electromagnet 10 to the contact support frame 4, And an electromagnet device for driving the motor. 12 is an electromagnet 1
Reference numeral 13 denotes a return spring attached to the contact support frame 4.

Here, a thermosetting resin such as a phenol resin is used as a material of the contact support frame 4 in order not to hinder the movement of the second movable contact 7 due to deformation by heat and to improve heat resistance. If there is a mechanically weak part, a phenol resin with cloth is used. In the case of cloth-containing phenolic resin, its heat resistance temperature is 150 ° C and shrinkage ratio is 1
%.

Next, the operation of the conventional electromagnetic contactor will be described. The driving force generated by the attraction force of the electromagnet 10 is transmitted to the contact support frame 4 via the link 11, and moves the contact support frame 4 from top to bottom in FIG. Then, the three-pole first movable contact 1 supported in parallel by the moved contact support frame 4 at a constant equal interval also moves to reduce the interval between each movable contact 2 and each fixed contact 6, and substantially At the same time, the contacts come into contact and start energization. Thereafter, the contact support frame 4 moves further while compressing the pressing spring 3, and holds the attraction force state of the electromagnet 10 at a certain position after stopping. At that time, the electromagnet 1
Although the driving force of 0 continues to be applied, when this driving force disappears, the contact support frame 4 is moved upward from the bottom in FIG. 2 by the return spring 13, and the contacts are separated almost simultaneously.

[0005]

In the above-described conventional electromagnetic contactor, the three-pole first movable contactor 1 is mounted on the contact support frame 4.
Are supported in parallel at regular intervals, and each first movable contact 1
Since the distance between the movable contact 2 of the first fixed contact 5 and the fixed contact 6 of each first fixed contact 5 is formed at the same distance A between any contacts,
In the initial state of use of the electromagnetic contactor, when the contact support frame 4 is moved up and down by the electromagnet 10, the movable contact 2 of the first three-pole movable contact 1 and the fixed contact of the first three-contact fixed contact 5 are formed. 6 operate so as to be opened almost simultaneously. However, even when the period of use of the electromagnetic contactor is relatively short, the heat generated from the movable contacts 2 and the electromagnets 10 causes the contact support frame 4 to move through the contact support frame 4 because the synthetic resin contact support frame 4 has a large heat shrinkage. It contracts, and the amount of contraction saturates, causing a difference in the contact interval as shown in FIG. The difference is the contact support frame 4
The distance between the contact points increases as the distance from the fulcrum 4a of the driving force increases, and A <D <E, as shown in FIG. This is because the contraction of the contact support frame 4 substantially uniformly shrinks as a whole, and the influence of the contact support frame 4 becomes greater as the contact support frame 4 is located farther from the fulcrum 4a of the driving force.

As described above, when the contact interval gradually increases from A to E, the timing of the opening is disturbed, and the arc is concentrated between the contacts of one pole, so that there is a problem that the consumption of the contact of one pole is accelerated. Was.

[0007] Further, when the contact interval gradually increases from A to E, the contact contact pressure of the pressing spring 3 at the time of contact is lower than that at the contact portion where the interval is increased. However, there is a problem that the problem is easily caused. Therefore, in order to solve such a problem, in consideration of the expansion of the contact interval, that is, the contraction of the contact support frame 4, both triodes are initially set so that the minimum contact contact pressure can be maintained even when the contact interval increases. Although the urging force of the pressing spring 3 is set to be large, in this case, there is a problem that the suction by the electromagnet 10 becomes difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to prevent the concentration of contact wear and to prevent the occurrence of contact welding before the limit of contact wear and to provide a stable electric power for a long time. It is an object to obtain an electromagnetic contactor capable of maintaining proper performance.

[0009]

SUMMARY OF THE INVENTION An electromagnetic contactor according to the present invention is an electromagnetic contactor which is formed of a movable contact and a fixed contact facing the movable contact. The plurality of movable contacts are supported on the contact support frame so as to gradually narrow as they move away from the fulcrum that receives the driving force, and the urging force of the pressing spring for urging each movable contact is applied to the fulcrum that receives the driving force of the contact support frame. , The urging force of the pressing spring at least farthest from the fulcrum is set to be stronger than the urging force of the pressing spring at the closest distance.

Further, it is preferable that the contact support frame is formed of polyphenylene sulfide resin.

[0011]

In the present invention, the distance between each movable contact and the fixed contact opposed thereto is gradually reduced as the distance from the fulcrum receiving the driving force of the electromagnet device in the sliding resin contact support frame increases. Since the plurality of movable contacts are supported by the contact support frame so that the contact support frame made of resin contracts due to use for a relatively short time, and reaches a saturation point, the driving force of the contact support frame is increased. The distance between the movable contact and the fixed contact located at a long distance from the fulcrum receiving the contact is substantially equal to the distance between the movable contact and the fixed contact located at a short distance.

Further, the urging force of the pressing spring for urging each of the movable contactors may be sequentially set to be stronger as the distance from the fulcrum receiving the driving force of the contact support frame increases, or the urging force of the pressing spring at least farthest from the fulcrum may be set. Since the biasing force is set stronger than the closest biasing force, even if the contact support frame shrinks due to heat after a relatively short period of use, the contact interval widens and the contact contact pressure decreases, the biasing force of the pressing spring is set in advance. Is increased, the decrease is offset, and the minimum contact contact pressure between each contact or between some contacts is prevented from decreasing.

Further, since the contact support frame is formed of polyphenylene sulfide resin, the contact support frame has a heat resistance temperature of 240 ° C. and a shrinkage rate of about 0.15%. The contact support frame has a small amount of contraction after a long-term use, and can maintain the distance between the movable contact and the fixed contact for a long time.

[0014]

FIG. 1 is a sectional view of a contact support portion of an electromagnetic contactor according to an embodiment of the present invention. FIG. 3 is a sectional view showing the initial use state of the contact support of the conventional electromagnetic contactor, but also showing the state after long-term use of the contact support of the electromagnetic contactor according to one embodiment of the present invention. . In the figure, the same components as those of the conventional example are denoted by the same reference numerals, and the description of the duplicated components will be omitted. In this embodiment, the distance between the first movable contactors 1 of three poles and the first fixed contactors 5 opposing each other is gradually reduced as the distance from the fulcrum where the contact support frame 4 is driven is reduced. The three-pole first movable contact 1 is supported in parallel to the contact support frame 4. Further, the urging force of the pressing spring 3 for urging each first movable contact 1 is sequentially set to be stronger as the distance from the fulcrum 4 a receiving the driving force of the contact support frame 4 increases.

In the electromagnetic contactor constructed as described above, the distance between the first movable contacts 1 of three poles and the first fixed contacts 5 opposing to each other is set to drive the contact support frame 4. Since the contact support frame 4 made of resin is formed so as to gradually become narrower as the distance from the fulcrum 4a receiving the force increases, the movable contact 2 and the electromagnet 10
The distance C between the first movable contact 1 and the first fixed contact 5 that is farthest from the fulcrum 4a that receives the driving force of the contact support frame 4 when it is contracted by the heat generated from the contact point and reaches the saturation point. Is about the same as the initial distance A between the first movable contact 1 and the first fixed contact 5 that are closest to each other. The distance B between the first movable contact 1 and the first fixed contact 5 at the intermediate distance is also substantially equal to the distance A and the distance C. This is because the contraction of the contact support frame 4 occurs almost uniformly as a whole, so that the greater the distance from the fulcrum 4a receiving the driving force, the greater the effect. This is because it is sufficient to narrow the interval C between the objects located far from 4a.

[0016] Thus, relatively from the short period is used for a long time, respectively at a first fixed contact 6 of the fixed contacts 5 respectively opposite thereto and the movable contact 2 of the first movable contact 1 tripolar Since the gaps formed are substantially equal to each other, the timing of the separation between each movable contact 2 and each fixed contact 6 is not disturbed, the arc does not concentrate on one pole, and the contact consumable does not concentrate on one pole. .

In addition, the contact support frame 4 contracts due to heat due to relatively short-term use.
As the distance between the movable contact 2 and the fixed contact 5 gradually increases from the short distance to the long distance of the fulcrum 4a, the contact pressure between the contacts by the pressing spring 3 also increases with the distance. The position of the pressing member 3 for biasing each first movable contact 1 is set to gradually increase as the distance from the fulcrum 4a, which initially receives the driving force of the contact support frame 4, is gradually reduced as the position is increased. Therefore, the decrease in the contact pressure is offset, and after a relatively short period of use, the contact pressure between the contacts is substantially equal, and the minimum change in the contact pressure is small. Therefore, there is no danger of contact welding before the contact wear limit due to a decrease in contact contact pressure.

Further, if the urging force of the pressing spring 3 farthest from the fulcrum 4a receiving the driving force of the contact support frame 4 is set to be stronger than the urging force of the pressing spring 3 at the shortest distance, The danger of contact welding due to a decrease in contact pressure is reduced, and only a part of the urging force of the pressing spring 3 is increased. Therefore, as compared with the conventional example, the urging force of the three-pole pressing spring 3 is increased. There is no difficulty in attracting the electromagnet.

When the contact support frame 4 is formed of polyphenylene sulfide resin, the movable contact 2 of the three-pole first movable contact 1 and the fixed contact 6 of the first fixed contact 5 opposed thereto are formed. 2, the polyphenylene sulfide resin has a heat-resistant temperature of 240 ° C. and a small shrinkage of 0.15%, and has been used for a long time. The interval A, which was initially A, is maintained at A.

For example, for an electromagnetic contactor having a rated current of 12 A class, if the contact support frame 4 is made of phenolic resin, the gap between the movable contact 2 and the fixed contact 5 is about 0.
Although it is larger than 5 mm, polyphenylene
With a sulfide resin material having a thickness of less than 0.1 mm, it has been proved to be very good against contact wear and contact welding.

[0021]

As described above, according to the present invention, the distance between each movable contact and the fixed contact opposed thereto is gradually reduced as the distance from the fulcrum receiving the driving force of the contact support frame decreases. The movable contacts of the plurality of movable contacts and the fixed contacts facing the movable contacts in a state where the amount of contraction due to heat of the contact support frame is saturated after a relatively short period of use after the movable contacts are supported by the contact support frame. Since the intervals formed with the fixed contacts are made equal, even when the contact surface is worn and approaches the danger area of welding, the timing of contact opening coincides, so the arc is dispersed to each pole, This has the effect that overconcentration of wear can be prevented. Further, the urging force of the pressing spring for urging each movable contact may be sequentially set to be stronger as the distance from the fulcrum receiving the driving force of the fulcrum support frame increases, or the urging force of the pressing spring at least the farthest distance from the fulcrum may be set to the nearest. The urging force of the pressing spring is set to be stronger than the urging force of the distance, and the urging force of the pressing spring is strengthened in advance even if the contact support frame shrinks due to heat after a relatively short period of use and the contact contact pressure is widened and the contact contact pressure is reduced. In order to eliminate the decrease in the contact pressure and to minimize the decrease in the minimum contact pressure between each contact or some of the contacts, the danger of contact welding before the contact wear limit due to the decrease in contact contact pressure Therefore, there is an effect that suction of the electromagnet device can be easily performed.

Further, since the contact support frame is made of polyphenylene sulfide resin to prevent the contact support frame from contracting itself, the space formed by the plurality of movable contacts and the fixed contacts opposed thereto is provided. However, there is no problem that the concentration of the poles of the arc is concentrated or the contact pressure of the contacts is reduced, and that the concentration of the poles of the contacts is concentrated and the danger of contact welding is not small.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a contact support portion of an electromagnetic contactor according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the entire mechanism of a conventional electromagnetic contactor.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a sectional view showing a state after using a contact support portion of the electromagnetic contactor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first movable contact 3 press spring 4 contact support frame 4 a fulcrum 5 first fixed contact 10 electromagnet (electromagnet device) 11 link (electromagnet device)

Claims (2)

(57) [Claims] 1. A plurality of movable contacts arranged in parallel at intervals, a resin contact support frame which supports these movable contacts via a pressing spring and slides in the direction in which the movable contacts are arranged, In an electromagnetic contactor including a fixed contact placed opposite to each movable contact and an electromagnet device for driving the contact support frame, the electromagnetic contactor is formed by each movable contact and a fixed contact facing the movable contact. A biasing force of a pressing spring for supporting the plurality of movable contacts on the contact support frame so that the distance becomes gradually smaller as the distance from the fulcrum receiving the driving force of the electromagnet device in the contact support frame increases, and biases each movable contact. Or the biasing force of the pressing spring at least farthest from the fulcrum is set to be stronger than the biasing force of the pressing spring at the shortest distance. Characterized by Electromagnetic contactor. 2. A plurality of movable contacts arranged in parallel at intervals, a resin contact support frame supporting the movable contacts via a pressing spring and sliding in the direction in which the movable contacts are arranged, In an electromagnetic contactor provided with a fixed contact placed opposite to each movable contact and an electromagnet device for driving the contact support frame, the contact support frame is formed of polyphenylene sulfide resin. Electromagnetic contactor.