JPH02304833A - polarized electromagnetic relay - Google Patents

Abstract

PURPOSE:To reduce temperature dependence of relay load operating characteristics with a simple structure to enable hot start by a method wherein a movable contact piece with a contact is made of a reversible shape memory alloy wherein memory is set so that the contact piece is bent to be low in relay operating voltage at specific temperature or higher which is higher than room temperature. CONSTITUTION:A movable contact piece 15 is made of reversible shape memory alloy, for example nickel-titanium or copper shape memory alloy, wherein the memory is set so that the contact piece is bent in a direction that relay operating voltage is lower when temperature is higher than a specific value which is higher than room temperature. Thus the movable contact piece 15 is made of a reversible shape memory alloy and if the temperature is higher than a specific value a movable contact 6 is displaced toward a direction wherein relay voltage becomes lower so that large relay operating voltage is not required even if the ambient temperature rises, thereby improving relay load operating characteristics in a high temperature use region. Thus hot start is possible even under severe atmospheric conditions higher than the ambient temperature, while the structure is simple and can be cheaply manufactured since a fan and a constant voltage device are not needed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a polarized electromagnetic relay that opens and closes contact portions by the attractive force of an electromagnet.

(Summary of the Invention) The present invention includes forming a movable contact piece of a polarized electromagnetic relay from a reversible shape memory alloy, and configuring the movable contact piece to curve in a set direction at a predetermined temperature higher than room temperature. This is designed to reduce the temperature dependence of relay operating characteristics.

(Prior Art and its Problems) As a conventional polarized electromagnetic relay, there is one in which a movable contact portion of a movable contact piece is operated by the attractive force of an electromagnet to open and close a relay circuit.

FIG. 5 shows an example of the configuration of such a polarized electromagnetic relay, in which an electromagnet 4 consisting of an iron core 1 and a yoke 2 around which a coil 3 is wound is housed in a cover 14, and the coil 3 is housed in a cover 14.
A movable contact piece 15 that operates depending on the presence or absence of energization is biased toward the return position and is provided on the base 21, and the movable contact 6 of this movable contact piece 15 can approach and separate from the fixed contacts 8a and 9a. It is set in. In addition, 23 is a movable contact piece 15
This is a resin movable member inserted between the electromagnet 4 and the electromagnet 4.

However, in a polarized electromagnetic relay with such a structure,
When the ambient temperature of the electromagnet rises above room temperature during use, the magnetomotive force of the coil itself drops rapidly, so the attraction force to the movable contact piece 15 decreases, and the relay operating voltage required to obtain a predetermined attraction force increases significantly. do. Therefore, when using conventional polarized electromagnetic relays at high temperatures, the relay load operating characteristics change significantly as the temperature rises. As a result, there is a problem in that it becomes difficult to hot start the polarized electromagnetic relay, resulting in malfunction.

By the way, in order to maintain normal operation under conditions of high ambient temperature, a fan may be provided near the polarized electromagnetic relay, or a constant voltage device may be provided. However, providing such accessories not only complicates the configuration but also increases costs.

(Object of the Invention) The present invention solves the above-mentioned problems, and aims to provide a polarized electromagnetic relay that has a simple configuration, reduces temperature dependence of relay load operating characteristics, and enables hot start. do.

(Structure and Effects of the Invention) In order to achieve the above-mentioned objects, the present invention has a movable contact piece with a contact that is absorbed and operated by an electromagnet, and is made of a reversible shape memory alloy, and the relay operating voltage decreases at a predetermined temperature higher than room temperature. It is characterized by being stored and set so that it curves and deforms in a direction where it becomes lower.

Therefore, according to the present invention, since a reversible shape memory alloy is used as the movable contact piece, the movable contact piece bends at a predetermined temperature above room temperature and operates in the direction of lowering the relay operating voltage. Even if the temperature rises above normal temperature,
It is possible to suppress the relay operating voltage required to obtain a predetermined attraction force to the movable contact piece from increasing with temperature. This improves relay load operating characteristics with respect to temperature changes, enables hot starting even under harsh atmospheric conditions with high ambient temperatures, and simplifies configuration as no fan or voltage regulator is required. can be manufactured at low cost.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a flexure type polarized electromagnetic relay, in which an electromagnet consisting of an iron core 1 and a yoke 2 around which a coil 3 is wound is housed in a box-shaped cover 14. A movable contact piece 15 is disposed on the magnetic pole side of the iron core 1 via an armature 5 and a movable spring mold 13. The movable contact piece 15 is urged toward the return position by the return spring 11, and the movable contact 6 fixed at the tip thereof is connected to the break side terminal 7 as shown in FIG. The fixed contacts 7a and 8a of the meter side terminal 8 are provided so as to be able to come into contact with and separate from them.

In addition, 4a and 9 are a coil terminal and a common terminal respectively protruding to the outside of the cover 14, and 10 is a terminal plate fixed to the inner surface of the cover 14.

Further, 12 is a rivet for fixing the movable spring mold 13 to the armature 5.

The movable contact piece 15 is made of a reversible shape memory alloy, such as a nickel-titanium or copper shape memory alloy, and when the temperature exceeds a certain temperature higher than room temperature, the relay operating voltage decreases (R in FIG. 2). It is stored and set to curve in the direction).

The bending point of this movable contact piece 15 is set at the second point so that the required displacement of the movable contact 6 on the tip side can be obtained with a small deformation.
As shown by the symbol F in the figure, this is the root portion of the movable contact piece 15. Of course, it is also possible to set it not at the base but at the center or tip of the movable contact piece 15 depending on the operating temperature of the electromagnetic relay.

In this way, the movable contact piece 15 is made of a reversible shape memory alloy, and the movable contact 6 is displaced in the direction where the relay voltage becomes weaker when the temperature exceeds the set temperature, so even if the ambient temperature rises, the relay operating voltage remains high. This improves relay load operating characteristics in high-temperature usage areas, and prevents inoperability due to hot starts.

Figure 3 shows another embodiment of this invention, in which the base 2
There is an iron core 1 on top of 1. An electromagnet 4 consisting of a yoke 2 and a coil 3 is mounted and fixed, and a resin movable member 23 having a magnetized surface 22 is provided so as to be movable laterally in the width direction WW of the base 21.

Thereby, the movable contact piece 15 moves towards and away from the fixed contacts 8a and 9a via the card 20 of the movable member 23 in response to ON and OFF of the excitation current to the electromagnet 4.

The movable contact piece 1.5 is made of a reversible shape memory alloy as in the previous embodiment, and the whole extends straight at room temperature as shown in FIG. 4(a). However, when the ambient temperature of the electromagnetic relay rises and reaches a set temperature of 10 or higher, which is higher than room temperature, the tip end portion 15a of the movable contact piece 15 moves a predetermined distance Δ1 toward the fixed contact 8a, as shown in FIG. 4(b). It is set to curve.

That is, when the set temperature is 10 or more, the position of the movable contact 6 of the movable contact piece 15 is curved so as to change by a predetermined distance toward the side where the relay operating voltage becomes weaker.

Therefore, the relay can be operated with a smaller load voltage during bending.

Then, when the temperature drops to the set temperature 10 or more again, the movable contact piece 15 returns to the straightly extended state as shown in FIG. 4(a).

Note that the position C in FIG. 4 indicates the position of the card 20. In other words, since this is an electromagnetic relay for small signals, the relationship between the curved part 15a, the card 20, and the movable contact 6 is as follows: base of the movable contact piece 15 - card 20 - curved part 15a = movable contact 6. It has become.

In this embodiment, the shape change temperature of the movable contact piece 15 is set to the temperature T.
Although only o is used, it is also possible to set the temperatures to T1 and T2, which are different from each other.

As described above, in this invention, the movable contact piece 15 is bent when the temperature exceeds the set temperature, and the operating voltage of the relay is reduced. Therefore, the relay load operating characteristics in the region above the contact temperature are improved, compared to the conventional one. Hot-starting of relay operation becomes possible even under severe high-temperature conditions, and polarized electromagnetic relays can be used over a wide temperature range.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the present invention, FIG. 2 is a sectional view showing the electromagnet section of FIG. 1, FIG. 3 is an overall perspective view showing another embodiment of the invention, and FIG. 4 3 is a plan view of a main part explaining the operation of the movable contact piece shown in FIG. 3, and FIG. 5 is an exploded perspective view showing a conventional example. 1... Iron core 3... Coil 6... Movable contact 15... Movable contact piece

Claims (1)

[Claims] 1. The movable contact piece with a contact that is absorbed by an electromagnet is made of a reversible shape memory alloy, and is memorized so that it curves and deforms in the direction of lowering the relay operating voltage at a predetermined temperature higher than room temperature. A polarized electromagnetic relay.