JPS63313443A - Electromagnetic relay - Google Patents

Abstract

PURPOSE:To make an electromagnetic relay smoothly operable with a simple structure by installing an auxiliary coil, which is smaller in resistance than a main coil, wound in the same direction as the main coil, and connected to the main coil in parallel and, when being impressed with the rated voltage, it is burned out and intercepted from the main coil, in an electromagnet. CONSTITUTION:An auxiliary coil 46, which is extremely fewer in the number of turns and smaller in resistance than a main coil 44, is branched off from this main coil 44 and wound on an iron core 42 in the same direction as the main coil 44, then it is connected to a relay terminal 48 via a fuse 47. At time of initial action after ultrasonic cleaning, if rated voltage is impressed in space between coil terminals 12 and 12', since an electromagnet 40 becomes plenty of the number of turns as much as a portion for the auxiliary coil 46, such a magnetic field that is high in magnetic flux density is securable as compared with the case of the main coil 44 alone. With this constitution, such an electromagnetic relay as capable of doing its operation easily is produced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an electromagnetic relay.

(Prior Art) Generally, after an electromagnetic relay is mounted on a printed circuit board or the like by soldering, it is subjected to ultrasonic cleaning to remove black from the soldered portion.

(Problems to be Solved by the Invention) - However, the ultrasonic waves during ultrasonic cleaning caused contact adhesion between the fixed contact and the movable contact, and the contact did not work even if the rated voltage was applied after cleaning. A voltage higher than the rated voltage had to be applied.

In addition, collisions between contacts caused by ultrasonic waves cause the contact surface layers of the contacts to break, exposing the underlying layer, resulting in lower contact reliability.

Therefore, measures have been taken to prevent contact sticking during ultrasonic cleaning, such as lowering the ultrasonic frequency and using harder contact materials, but changing the ultrasonic output results in insufficient cleaning. Furthermore, if a material with high hardness is used, the contact resistance becomes unstable and the contact reliability deteriorates, making selection of the contact material extremely difficult.

The present invention has been made in view of such problems, and an object of the present invention is to provide an electromagnetic relay that can be easily operated even if contact sticking occurs due to ultrasonic cleaning.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an electromagnetic relay that is subjected to ultrasonic cleaning after being mounted on a board, in which the electromagnet has a resistance lower than that of the main coil, and is connected to the main coil. An auxiliary coil is provided that is wound in the same direction and connected in parallel to the main coil, and is fused and cut off from the main coil when a rated voltage is applied.

(Function) When the rated voltage is applied during initial operation, an electromagnet with a magnetic flux density higher than that of the auxiliary coil is formed, and even if the contacts stick during ultrasonic cleaning, the contacts will open. At the same time, the magnet is cut off by Joule heat and is cut off from the main coil, so after the cutoff, the electromagnet is formed only by the main coil.

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

FIGS. 2 and 3 show an electromagnetic relay according to the present invention, and this electromagnetic relay is generally composed of a base lO, a yoke 20, a contact mechanism 30.30°, an electromagnet 40, a card 50, and a case 60. ing.

The base 10 is made of synthetic resin, 11 is a support shaft for supporting the card 50, and 12, 12°, and 13 are coil terminals.

The yoke 20 is made by bending a plate material into an abbreviated shape, and is provided with a tip upright piece (not shown) on one side of the tip, and a rear end upright piece 21 on the rear end, which is inserted when the base 10 is molded. It is fixed integrally. Further, a notch 22 is formed in the rear end upright piece 21.

The contact mechanisms 30, 30' are installed on both sides of the base 10, and as shown in Fig. 2, the common terminals 31, 31° and the rear end are fixed to the common terminals 31, 31°, and the tip has twin terminals. Movable contact piece 32. with a movable contact point 33.33°.
32', a normally closed fixed terminal 34.34' having fixed contacts 35, 35°, and a normally open fixed terminal 36.36° having fixed contacts 37.37'.

The electromagnet 40 has a main coil 44 wound around an iron core 42 via a spool 41, and both ends of the main coil 44 are connected to relay terminals 45 and 45' provided on the spool 41 (relay terminal 4 on the back side in FIG. 3).
5 degrees (not shown), and as shown in FIG.
An auxiliary coil 46 with low resistance was branched from the main coil 44, wound around the iron core 42 in the same direction as the main coil 44, and connected to the relay terminal 48 via a fuse 47 (not shown in FIG. 2). It is something. In addition, 43 is the iron core 42
It is a thin magnetic shielding plate attached oppositely to both sides of the

The card 50 has a substantially mouth-shaped shape, and a bearing recess 51 is formed at the rear end from the lower surface, and a pair of iron pieces 53a facing each other with a permanent magnet 52 in between is provided at the tip.

53b is attached. Furthermore, grooves 54, 54' (the grooves 54' on the back side in FIG. 3 are not shown) are formed on both sides of the card 50 from below in the front-rear direction. As shown in FIG. 2, the groove portions 54 and 54' are provided with protrusions 55.degree., 55.degree. and 56.56' on the respective groove sides.

The assembly of each component having the above configuration will be explained.

First, the electromagnet 40 is fixed by fitting the protruding end portion of the iron core 42 on the back side (not shown in FIG. ', 13 and fixed to the base IO.

Next, the card 50 is inserted into the bearing recess 51 with the support shaft 11 of the base 10, and the protrusions 55 and 56 of the groove 54 are inserted into the groove 54.
Movable contact pieces 32.3 with protrusions 55° and 56° respectively
2°, and further an iron piece 53a.

53b are positioned on both sides of the iron core 42 and attached to the base 10. Then, energize between the coil terminals 12 and 12',
Check the continuity of the main coil 44 and the operating characteristics of the electromagnetic relay,
After adjustment, the case 60 is attached to the base IO and sealed.

Finally, coil terminals 12 and 13 are connected with jumper wires 70. Thereby, the auxiliary coil 46 is connected in parallel to the main coil 44.

Note that when the electrical relay is mounted on a printed circuit board without using the jumper wire 70, the coil terminals 12 and 13 may be electrically connected by a conductive pattern provided on the printed circuit board.

The electromagnetic relay assembled in this manner is mounted by a user on a printed circuit board or the like by soldering, and subjected to ultrasonic cleaning. At this time, adhesion occurs between the contacts due to the ultrasonic waves, and the following operation will be explained assuming that contact adhesion has occurred between the movable contact 33 and the fixed contact 35.

During initial operation after ultrasonic cleaning, coil terminal 12.
When a rated voltage is applied between 12', the number of turns of the electromagnet 40 is increased by the amount of the auxiliary coil 46, so a magnetic field with a higher magnetic flux density can be obtained compared to the case of only the main coil 44.

FIG. 4 shows an operating characteristic curve of an electromagnetic relay, where the horizontal axis is the stroke of the card 50, and the direction from the right side to the left side in the figure coincides with the upward direction a in FIG. In addition, A on the vertical axis is a load curve, B is an attractive force curve when only the main coil is energized and excited, and Bo is the main coil 44 and the auxiliary coil 4.
6 is energized and excited.

In FIG. 4, if only the main coil 44 is energized and excited, the card 50 is moved from the right side in FIG. 4 along the load curve A to the left side (in FIG. a direction), but at point S,
If the contact adhesive force is greater than the spring return force + suction force ro (however, in Fig. 4, it is -, and the suction force does not work),
It does not open and becomes inoperable. However, in the case of this embodiment, at the time of initial operation, the main coils 4 connected in parallel
4 and the auxiliary coil 46 are energized to generate a magnetic field with high magnetic flux density, and an attractive force f is added to the spring return force. The movable contact 33 and fixed contact 35 that are stuck are separated from each other because 10 fa is applied and a return force greater than the contact adhesive force is applied.

Furthermore, due to the rated voltage applied between the coil terminals 12 and 12', an overcurrent flows through the auxiliary coil 46 with low resistance, so the fuse 47 blows due to Joule heat and the auxiliary coil 46 is cut off from the main coil 44. , main coil 44
Current will flow only to the side. Therefore fuse 4
Until 7 is fused, it operates according to the attraction force curve B', and the stuck contacts are separated, and after the fuse is blown, it operates according to the attraction force curve B.

Next, the operation of the electromagnetic relay after the initial operation, that is, after the stuck contacts are separated and the fuse 47 is blown, will be described.

When the electromagnet 40 is not energized, the magnetic force of the permanent magnet 52 causes the iron piece 53a of the card 50 to be attracted to the not-illustrated tip upright piece of the yoke 20, and the iron piece 53b to be attracted to the iron core 42. It rotates in the opposite direction to the direction of arrow a in Figure 3. At this time, the protrusion 56.5 of the card 50
5' presses the movable contact piece 32.32° downward in FIG. 2 to connect the movable contact 33.33' and the normally closed fixed contact 35.
35' is closed.

Subsequently, when the electromagnet 40 is energized, the iron piece 53a is repelled by the not-illustrated tip upright piece of the yoke 2 and adsorbed to the iron core 42, and the iron piece 53b is repelled by the iron core 42, so that the card 50 is Rotate in the direction of arrow a in Figure 3. At this time, the protrusions 55, 56' of the card 50 press the movable contact pieces 32, 32° upward in FIG. do.

Then, when the electromagnet 40 is de-energized, it returns to the non-excited state.

In the above embodiment, the fuse 47 is attached to the auxiliary coil 46.
is provided so that the fuse 47 is blown when the rated voltage is applied, but a thin coil wire may be used for the auxiliary coil 46 itself so that it is easily blown by Joule heat.

(Effects of the Invention) As is clear from the above description, according to the present invention, even if contact stickiness occurs due to ultrasonic cleaning after mounting,
Able to operate at rated voltage.

For this reason, there is no need to increase the initial operating voltage, and there is no need to use special contact materials that are less likely to cause contact sticking, resulting in effects such as being able to operate smoothly with a simple configuration.

[Brief explanation of drawings]

Fig. 1 is a wiring diagram of a coil of an electromagnetic relay according to the present invention, Figs. 2 and 3 are a plan view and an exploded perspective view of the electromagnetic relay, and Fig. 4 is a diagram showing an operating characteristic curve of the electromagnetic relay. be. 40...Electromagnet, 44...Main coil, 46...Auxiliary coil, 47...Fuse, 70...Jumper wire. Patent applicant: Tateishi Electric Co., Ltd. Representative: Patent attorney: Aohaku Ao and 2 others Figure 4

Claims (1)

[Claims] (1) In an electromagnetic relay that undergoes ultrasonic cleaning after being mounted on a board, the electromagnet has a resistance lower than that of the main coil, is wound in the same direction as the main coil, and is connected in parallel to the main coil. An electromagnetic relay characterized by having an auxiliary coil that fuses and is cut off from the main coil when a rated voltage is applied.