JPS6332820A - Polar electromagnetic relay - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polarized electromagnetic relay, and more particularly to a structure for improving the welding resistance of its contacts.

(Prior Art) As a conventional electromagnetic relay, there is one shown in FIG. 5, for example.

spool! a coil 3 wound around the iron core 2; a yoke 4 extending from one end of the iron core 2 to the lower side of the spool l and positioned in the form of a mouth on both sides of the other end of the iron core 2; 4 forms a magnetic circuit of an electromagnet.

A movable contact piece 5 is fixed at one end to the side of the coil 3, and a movable contact 6 is formed at the free end of the movable contact piece 5. Further, a fixed terminal piece 7a having a fixed contact 7 located opposite to the movable contact 6 is provided.

On the other hand, above the coil 3, a substantially rectangular card 8 is provided so as to be swingable in the horizontal direction by a rotating shaft 9 provided at one end thereof. A pair of movable iron pieces 11.12 formed in a gate shape are attached to the other end of the card 8 via a permanent magnet 10 so as to be positioned between the iron core 2 and the yoke 4.4. Further, a pair of first pressing portions 13 are provided at the side ends of the card 8 so as to sandwich the movable contact pieces 5 therein. A second pressing portion 14 is provided.

By energizing and demagnetizing the electromagnet, magnetic repulsion or attraction between the polar movable iron piece 11.12 and the iron core 2 or yoke 4.4 is applied to the first pressing portion of the card 8. The movable contact piece 5 is driven via the second pressing part 13 and the second pressing part 14, and the movable contact 6 and the fixed contact 7 are brought into contact and separated, thereby opening and closing the contacts.

FIG. 6 shows the operating characteristic curve of such a polarized electromagnetic relay, where the horizontal axis is the stroke of the card 8, the vertical axis is the attractive force and load, and curve A is the plate attraction curve when not energized. B shows the attraction force curve at rated voltage excitation, and curve C shows the load curve. Further, in the figure, from the right side to the left side of the horizontal axis is the operating side, and from the left side to the right side is the return side.

When the electromagnet is excited, the attractive force shown by curve B exceeds the load shown by curve C, so the first pressing part 13 of the card 8 presses the movable contact piece 5, and the movable contact 6 contacts the fixed contact 7. It becomes operational.

In this operating state, when the electromagnet is demagnetized, the attractive force shown by curve A is lower than the applied load, so the first pressing part 13 of the card 8 is pressed by the spring reaction force of the movable contact piece 5, and the card 8 starts to move. . Then, when the card 8 reaches point S, the contacts open. At this time, if the contacts are welded, the contacts will not separate and will not return unless the force that tries to separate the contacts, that is, the contact separation force indicated by f1 in the figure, is greater than the welding force.

Next, card 8 is the point S. When the value exceeds , the attractive force toward the operating side shown by curve A becomes negative, that is, the return force becomes positive, so in addition to the return force due to the spring reaction force of the movable contact piece 5, the return force due to the magnetic circuit of the permanent magnet It works and returns.

(Problems to be solved by the invention) However, in the conventional polarized electromagnetic relay,
As the contact wears out, the contact contact position S1 moves toward the operating side, so the load curve becomes an extension of the curve before contact, as shown by the broken line in the figure. Therefore, the contact opening force when the contacts are worn out is f in the figure. As shown in Figure 2, there was a problem in that the contact separation force was smaller than the contact separation force before the contact was worn out, and the welding resistance was insufficient.

The present invention has been made in view of such problems, and an object of the present invention is to provide a polarized electromagnetic relay that has a large contact separation force when the contacts are worn out and has high contact welding resistance.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention presses a movable contact piece through a card by a magnetic circuit of an electromagnet and a permanent magnet, and a magnetic circuit is provided at the tip of the movable contact piece. In a polarized electromagnetic relay that opens and closes the contact by bringing a movable contact and a fixed contact provided on a fixed terminal into contact and opening, the return force due to the magnetic circuit of the permanent magnet when not energized is positive before the contact opens. A first pressing part presses the movable contact piece during operation, and a second pressing part presses the movable contact piece when returning.
A pressing part is provided on the card, and a gap is provided between the movable contact piece and the second pressing part.

That is, in FIG. 6, the plate attraction curve A moves to the left when it is not energized and reaches point S. is on the left side of point Sl, and at least the contact contact position, that is, point S
In , when not energized, the positive attractive force towards the return side by the magnetic circuit of the permanent magnet contributes to the return of the contact, and
The operating energy of the card is effectively utilized to increase the contact opening force and improve the welding resistance of the contacts.

(Example) Next, one embodiment of the present invention will be described with reference to the drawings.

Fig. 1 shows a polarized electromagnetic relay according to the present invention, which is substantially different from the conventional electromagnetic relay shown in Fig. 5 except for the magnetic circuit of the electromagnet and permanent magnet, and the contact pressing part of the card. Corresponding parts are given the same numbers and their explanation will be omitted.

The magnetic circuit of the electromagnet and permanent magnet is shown in FIG. That is, a movable iron core 15 that is supported at one end and swingable at the other end, a coil 3 wound around the movable iron core 15, and one end of which is in contact with the supporting end of the movable iron core 15, and A magnetic circuit of an electromagnet is formed by a yoke 16 whose other end is located opposite to the side surface of the swinging end of the movable iron core 15. A permanent magnet lO is arranged parallel to the swinging surface of the movable iron core 15, and a swinging end of the movable iron core 15 is installed upright on the N pole side of the permanent magnet 10, for example, from the side opposite to the yoke 16. A magnetic circuit of a permanent magnet is formed from the auxiliary yoke 17 located opposite to the side surface. Therefore, the auxiliary yoke I7 always has a constant magnetic pole, for example, the north pole, due to the permanent magnet 10.

One end of the card 8 is supported by a rotating shaft 9, and the swinging end of a movable iron core 15 is fitted to the other end. Therefore, the card 8 is adapted to swing in the horizontal direction in conjunction with the movable iron core 15. A first pressing part 13 and a second pressing part I4 are formed on the card 8, and as shown in FIG. 3, a gap B is formed between the second pressing part 14 and the movable contact piece 5 in the operating position. It is now possible to do so. This gap 12. Approximately half of the stroke corresponding to the contact spacing is appropriate. Further, the second pressing portion 14 is located closer to the contact point than the first pressing portion 13 is.

FIG. 4 shows the operating characteristics of the polarized electromagnetic relay constructed as described above. In the figure, the non-excited attraction force curve A shows that it has a negative attraction force, that is, a positive return force over the entire stroke from the return position to the operating position. This is because the magnetic circuit of the electromagnet does not form a closed loop passing through the permanent magnet 10 in the operating position, and when not energized, the movable iron core 15 is always attracted to the auxiliary yoke 17 side, that is, to the return side, and the electromagnet This is because the contact spring has a single return configuration (single stable type).

In addition, plate attraction curve B1 load load curve C1 at rated voltage excitation
The contact point follow-up zero load load curve is the same as that of the conventional one shown in FIG. In addition, point S1 is the contact contact position, S
, indicates the position where the second pressing portion 14 collides with the movable contact piece 5, and f and f indicate the contact separation force at points S+ and Se, respectively.

When the electromagnet is excited, the swinging end of the movable iron core 15 and the yoke 1
As shown in Figure 4, an attractive force acts between the
Since the suction force exceeds the applied load, the card 8 rotates around the rotating shaft 9, and the first pressing part 13 of the card 8 presses the movable contact piece 5, and as shown in FIG. 3, the movable contact 6 comes into contact with the fixed contact 7 and enters the operating state.

In this operating state, when the electromagnet is demagnetized, the first pressing portion 13 of the card 8 is pressed by the spring reaction force of the movable contact piece 5 shown by the curve C, and the card 8 begins to move. Then, the negative attractive force toward the operating side by the permanent magnet IO shown by curve A,
That is, when the positive attractive force toward the return side becomes larger and more dominant than the spring reaction force, the card 8 is returned by the return force of this curve A.

At this time, the second pressing portion 14 of the card 8 is in the gap Q.

The impact force fe due to the kinetic energy accumulated until the movable contact piece 5 moves by 5 and comes into contact with the movable contact piece 5 is at point S.

is added to the static contact opening force ft. Therefore, point S1
Even if the contacts are welded at the contact abutment position, the contact separation force of ft+fe is applied, so they are easily separated.

In addition, since the second pressing part of the card 8 is located closer to the contact than the first pressing part 13, the second pressing part 14 is in a movable contact position compared to the case where it is located at the same position as the first pressing part 13. The reaction force acting on the contact welding portion against the force pressing the piece 5, that is, the contact separation force becomes larger, and is effective in separating the contacts.

When the contact wears out and the contact tracking becomes zero, the load curve changes as shown by the broken line in Figure 4, but when the contact opens, the spring reaction force of the movable contact piece 5 shown by the broken line , and a return force based on the positive attraction force toward the return side by the permanent magnet lO shown by curve A, is added to the contact opening force f. Since the above-mentioned impact force re is applied at the same time, the welding resistance when the contact wears out is improved compared to the conventional case.

In addition, in the embodiment, the magnetic circuit is composed of the electromagnet,
Although the contact spring has a single return configuration (single stable type), the magnetic circuit is basically the same as that of the conventional polarized electromagnetic relay shown in Fig. It may be made to be different. That is, by cutting out one side of the yoke 4, the attraction force curve A during non-excitation shown in FIG. 6 can be moved to the left side in the figure.
It becomes possible to increase the contact separation force f0 when the contact is worn out.

(Effects of the Invention) As is clear from the above description, according to the present invention, in a polarized electromagnetic relay, the return force due to the magnetic circuit of the permanent magnet when not energized becomes positive before the contact opens. A first pressing part that forms a magnetic circuit and presses the movable contact piece during operation, and a second pressing part that presses the movable contact piece when returning.
A pressing part is provided on the card, and a gap is provided between the movable contact piece and the second pressing part.

Therefore, when the movable contact piece is not energized, the restoring force by the magnetic circuit and the impact force due to the kinetic energy until the second pressing part collides with the movable contact piece are added to the spring reaction force of the movable contact piece. It has the effect of increasing the contact separation force when worn out and improving the welding resistance of the contacts.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a polarized electromagnetic relay according to the present invention, Fig. 2 is a principle diagram of the magnetic circuit of an electromagnet and a permanent magnet, Fig. 3 is a partial plan view showing the operating state of the contact portion, and Fig. 4 5 is a plan view of a conventional polarized electromagnetic relay, and FIG. 6 is a diagram illustrating an operating characteristic curve of a conventional polarized electromagnetic relay. . 3... Coil, 5... Movable contact piece, 6... Movable contact, 7... Fixed contact, Death... Card, 10... Permanent magnet, 13... First pressing part, 14 ...Second pressing part,
15...Movable iron core, 16...Yoke, 17...Auxiliary yoke.

Claims (2)

[Claims] (1) A magnetic circuit of an electromagnet and a permanent magnet presses the movable contact piece through the card, and the movable contact provided at the tip of the movable contact piece and the fixed contact provided on the fixed terminal are brought into contact and separated to form a contact. In a polarized electromagnetic relay that opens and closes, a magnetic circuit is formed so that the return force due to the magnetic circuit of a permanent magnet when not energized is positive before the contact is opened, and a first magnetic relay that presses a movable contact piece during operation. A polarized electromagnetic relay characterized in that a pressing part and a second pressing part that presses a movable contact piece when returning are provided on a card, and a gap is provided between the movable contact piece and the second pressing part. (2) The polarized electromagnetic relay according to claim 1, wherein the second pressing portion is provided closer to the contact point than the first pressing portion.