JPH0560205B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electromagnetic relay, in particular, to a movable platform that moves an iron piece toward and away from the end magnetic pole surface of an iron core based on excitation and demagnetization of a coil, and that holds this iron piece. This invention relates to an electromagnetic relay that opens and closes a contact mechanism via a relay.

[Summary of the Invention] The present invention forms a gap on the opposite side of the coil among opposing surfaces of an iron core magnetic pole surface and an iron piece that approaches and separates in a direction perpendicular to the magnetic pole surface, and makes contact between the iron piece and the iron core magnetic pole surface. The surface is placed close to the point where the movable table drives the contact mechanism.

[Prior Art] A conventional electromagnetic relay is shown in FIGS. 7 to 11.

The resin spool 1 is made by integrally molding collar parts 1d and 1e which have terminal support parts 1b and 1c at both ends of a body part 1a, and one coil terminal 2 is attached to one terminal support part 1c, and the other one is Terminal support part 1b has 2
Two coil terminals 3, 4 and one bearing member 5 are each fixed by insert molding. This spool 1 is fixed at a predetermined position on the base 7 by fitting the protrusions 1f, 1f formed on the lower surface of the collar portions 1d, 1e into the holes 7c of the resin base 7, and applying thermal caulking. At this time, the base 8a of the yoke 8 is positioned by the protrusion 1f, and is clamped and fixed between the lower surface of the collars 1d, 1e and the base 7. Further, lower portions 2a, 3a of the coil terminals 2, 3 protrude downward from respective holes 7a, 7b of the base 7.

Both ends 9a and 9b of the coil 9 wound around the body 1a of the coil spool 1 are connected to coil terminals 2 and 4.
The end portion 9b is connected to the coil terminal 3 via the resistor 6.

On the other hand, the iron core 10 is the body part 1a of the coil spool 1.
The one end 10a is inserted into the upright piece 8 of the yoke 8.
It is press-fitted into the hole 8c of b and fixed by caulking. The protruding end 10b, which is the other end of the iron core 10 and protrudes from the spool 1, has magnetic shielding plates 16, 17 on both sides.
is press-fitted into a recess 7e formed in the rib 7d of the base 7.

The movable block 11 is composed of a resin movable base 12, a permanent magnet 13, and iron cores 14, 15.
4 and 15 are the movable base 1 holding the permanent magnet 13 between them.
It is fixed at 2. This movable platform 12 is an iron piece 1
4 and 15 are installed to face both side surfaces of the protruding end portion 10b of the iron core 10, and the upright piece 8d of the yoke 8 is located on the outside of the iron piece 14. Also,
A shaft portion 12a and a protruding piece 12b are provided on the side of the movable table 12.
However, ribs 12e are respectively provided protruding from the lower surface, and the shaft portion 12a is slidably inserted into the guide hole 5a of the bearing member 5, and the ribs 12e, 12e slide on the upper surfaces 7f, 7f of the rib 7d of the base 7. Position freely.

The base 7 has three fixed terminals 18, 19,
20 are fixed through the top and bottom by insert molding, fixed contacts 21 and 22 are fixed to the two opposing fixed terminals 18 and 19, and the other fixed terminal 20 has a movable terminal at the tip. The rear end of a movable contact piece 24 having a contact point 23 is fixed in a cantilevered state. The movable contact piece 24 is provided with the movable base 12.
A groove 12d formed in the protruding piece 12b is engaged with the groove 12d.

Note that the cover 25 is fixed on the base 7 and covers parts such as the coil 9 and the contacts 21, 22, 23.

In the electromagnetic relay configured as described above, when the coil 9 is not energized, an attractive force acts between the protruding end portion 10b of the iron core 10 and the iron piece 15 by the magnet of the permanent magnet 13. As a result, the movable block 11 moves upward in FIG. 9 and to the left in FIG.
3 closes the fixed contact 21.

On the other hand, when the coil 9 is energized, an attractive force acts between the protruding end 10b of the iron core 10 and the iron piece 14, and a repulsive force acts between the iron piece 15 and the movable block 11 moves downward in FIG. right side in the figure), and the movable contact 23 is replaced by another fixed contact 22.
Close.

(Problem to be solved by the invention) In the above electromagnetic relay, the movable block 1
The reciprocating movement of 1 involves the engagement of the end 12a with the guide hole 5a and the notch 7 formed in the barrier 7g of the base 7.
h and the neck portion 12c of the movable table 12, and an appropriate clearance is set between them so that guiding can be performed smoothly. However, there is a problem in that the movable block 11 moves by the amount of these clearances, which changes the operating characteristics.

This point will be explained in detail with reference to FIGS. 11 and 12. FIG. 11 illustrates the operating state of the electromagnetic relay, in which the iron piece 14
A suction force Fm is acting between the protruding end portion 10b of the iron core 10 and the protruding end portion 10b of the iron core 10. In addition, the driving point P of the movable contact piece 24
A reaction force Fc is acting on . These two forces are in opposite directions and have a relationship of Fm>Fc, and since the points of action are shifted, a rotational moment is generated.

By the way, if the length of the contact points O to P of the iron piece 14 with respect to the iron core 10 is _l , and the length from point O to the center of the attraction force Fm is _l2 , then the relationship _l2・Fm< _l1・Fc holds true. At this time, point Q moves away from iron core 10, and movable block 11 rotates counterclockwise in FIG. 12 about point O. This rotation occurs between the shaft portion 12b and the guide hole 5.
a and the clearance between the neck 12c and the notch 7h is regulated at the point where it becomes zero, and the driving point P is
Move to P′. This means that the movable contact piece ₂ is
4 means that the amount of deflection decreases. on the other hand,
At the time of return, the movable block 11 rotates clockwise in the same manner as described above, and the amount of deflection of the movable contact piece 24 decreases from the set value. Such movement of the driving point P causes an increase in the operating voltage and a decrease in the return voltage, resulting in variations in operating characteristics and a problem of lack of contact reliability.

One possible solution to the above problem is to reduce the clearance as much as possible, but considering the variation in dimensional accuracy during parts processing, it is practically impossible to make it any smaller than it is now, and it is cost-effective. It's not a good idea either.

[Means for Solving the Problems] Therefore, the electromagnetic relay according to the present invention is characterized in that a gap is formed on the end side of the iron core, which is the opposing surface of the iron piece and the magnetic pole surface of the iron core. In comparison with the prior art described above, the attraction surface between the iron core and the iron piece is reduced to the side of the contact driving point of the movable base. That is,
As shown in Fig. 2, the iron core and the iron piece face each other with a length between points O and Q, but form a gap between points O and O'.
Contact should be made only between points O′ and Q, and the suction force Fm
The center of is brought close to the driving point P.

[Operation] In the above configuration, the permeance between points O and O' decreases due to the gap, and the permeance between points O' and Q increases. Also, the fulcrum around which the movable table rotates is O'. Therefore, the center of the suction force Fm is close to the driving point P, and the displacement of the movable table rotating around the fulcrum O' is Δl ₂ , which is much larger than the conventional displacement Δl ₁ . is decreasing.

[Example] Hereinafter, each example of the present invention will be described with reference to FIGS. 1 to 6. The explanation of each embodiment will be limited to the parts related to the present invention, and the other configurations and operations are the same as the conventional ones shown in FIGS. 7 to 11, and the same parts are designated by the same reference numerals. The explanation will be omitted.

First embodiment (see FIG. 1) This first embodiment is based on the protruding end 10b of the iron core 10.
Cutouts 10d and 10e are formed on both sides of the point O.
Air gaps 30 and 31 are provided at points O' and O', and the iron core 10 and iron pieces 14 and 15 come into contact only between points O' and Q.

The force relationship between the attraction force Fm and the reaction force Fc of this object is the second
As shown in the figure. Both the reaction force Fc and the attraction force Fm by the movable contact piece 24 generate a rotational moment in the counterclockwise direction around the fulcrum O', and the movable base 12
The driving point P of moves to P', but the movable contact piece 24
The amount of displacement Δl ₂ that reduces the amount of deflection (contact follow) is significantly reduced compared to the conventional amount of displacement Δl ₁ .
Therefore, the operating characteristics are stabilized and the rotational moment (Fc·l ₄ ) is reduced, so that the frictional force at the positioning portion of the movable base 12, that is, the guide hole 5a and the notch 7h, is also reduced.

Specifically, as shown in FIG. 2, the permeance between points O and O' during operation is reduced by the presence of air gaps 30 and 31, and the magnetic flux is reduced between points O' and O'.
Concentrates mostly between Q. Therefore, the center of the attraction force Fm comes close to the driving point P, and the rotational moment (Fm·l ₃ ) also decreases. Therefore, iron core 10
If the notches 10d and _{10e of}
is also reduced, further improving the operating characteristics.

In addition, since the magnetic flux density between points O'Q increases, the attractive force (holding force) during operation increases, the resistance to external vibrations and shocks improves, and the magnetic flux concentrates near the coil 9. Therefore, the change in the attractive force caused by the excitation of the coil 9 becomes large, and the contacts can be driven with a small excitation force, thereby achieving high sensitivity. On the other hand, in a state during operation in which the dimensions between the iron pieces 14, 15 and the iron core 10 are equal, the permeance between the iron cores 14, 15 and the iron core 10 decreases, and the suction force becomes small. This means that notch 10
This means that the suction curve can be controlled by the depths of d and 10e.

Second Embodiment (See FIG. 3) In this second embodiment, notches 14a and 15b are formed in the opposing surfaces of iron pieces 14 and 15, and air gaps 30 and 31 are formed between them and the protruding end 10b of iron core 10. It was established.

Third embodiment (see FIG. 4) In this third embodiment, the protruding end 10b of the iron core 10
The magnetic shielding plates 16 and 17 provided on both sides of the magnetic field are cut in the middle, so to speak, and air gaps 30 and 31 are provided.

Fourth embodiment (see FIG. 5) In this fourth embodiment, the protruding end 10b of the iron core 10 is
Air gaps 30, 31 are formed between the iron pieces 14, 15 by forming gently tapered surfaces 10f, 10g on both sides of the iron pieces 14, 15.
It has been established.

Fifth Embodiment (See Figure 6) In this fifth embodiment, contrary to the fourth embodiment,
A gently tapered surface 14 is formed on the opposing surfaces of the iron pieces 14 and 15.
b, 15b, and the protruding end 10b of the iron core 10
Air gaps 30 and 31 are provided between the two.

[Effects of the Invention] As is clear from the above description, according to the present invention, a gap is formed on the side opposite to the coil among the facing surfaces of the iron piece and the iron core magnetic pole surface, so that the attraction surface between the iron core and the iron piece is It is reduced to the contact driving point side of the movable base,
The center of attraction force Fm moves toward the contact driving point. Therefore, the rotational moments Fm・l ₃ and Fc・l ₄ decrease,
The amount of displacement Δl ₂ of the contact drive point P is significantly reduced compared to the conventional Δl ₁ , preventing excessive increases and decreases in operating voltage and release voltage, reducing variations in operating characteristics and improving contact reliability. do. Furthermore, since the clearance of the guide portion of the movable base is the same as that of the conventional one, there is no need to particularly improve the dimensional accuracy during component machining, and no increase in costs will result. In addition, the reduction in rotational moment reduces friction at the guide portion of the movable base, making it possible to extend the life of the movable base.

[Brief explanation of drawings]

Fig. 1 is a plan view of the first embodiment, Fig. 2 is an explanatory diagram of its attraction force characteristics, Fig. 3 is a plan view of the second embodiment, Fig. 4 is a plan view of the third embodiment, and Fig. 5 is a plan view of the third embodiment. The figure is number 4
FIG. 6 is a plan view of the fifth embodiment. Figure 7 and subsequent figures show a conventional electromagnetic relay, where Figure 7 is an exploded perspective view, Figure 8 is its basic configuration, Figure 9 is a plan view with the cover cut away, Figure 10 is a vertical sectional view, and Figure 11 is a cross-sectional view. The figure is a plan view during operation, and FIG. 12 is an explanatory diagram of attraction force characteristics. 1... Spool, 9... Coil, 10... Iron core, 10b... Projecting end, 10d, 10e... Notch, 10f, 10g... Tapered surface, 11... Movable block, 12... Movable base, 13... Permanent magnet, 14, 15... Iron piece, 14a, 15a... Notch, 14b, 15b... Tapered surface, 21, 22
... Constant contact, 23 ... Movable contact, 24 ... Movable contact piece, 30, 31 ... Air gap.

Claims (1)

[Scope of Claims] 1. One end of an iron core inserted through the axis of a spool around which a coil is wound is made to protrude from the end of the spool, and a pair of iron pieces fixed to a movable table with a permanent magnet clamped thereto are The protruding end of the iron core is made to face the magnetic pole surfaces on both sides, and the movable base and the movable contact piece of the contact mechanism are connected on the side of the coil from the attraction surface between the magnetic pole surface of the iron core and the iron piece, so as to excite and demagnetize the coil. Based on this, the movable base together with the iron piece is driven in a direction perpendicular to the magnetic pole surface,
What is claimed is: 1. An electromagnetic relay for opening and closing a contact mechanism, characterized in that a gap is formed on the opposite side of the coil between the opposing surfaces of the iron piece and the iron core magnetic pole surface.