JPS5915451Y2 - AC electromagnet - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an AC electromagnet for operating an AC electromagnetic contactor or the like.

Generally speaking, in AC electromagnets, the attractive force pulsates from zero to the maximum value at a frequency twice the power supply frequency, producing a whirring sound, so in order to average out the attracting force and reduce the whine, the armature is shaded. A coil is provided.

According to the principle of the AC electromagnet with a shaded coil, on the polarized surface with a constant depth shown in FIG. Gap G1 and width 11 (first
In Figure B, the relationship between the sum of 11a and 11b), the gap G2 in the part P2 where the shaded coil is wound, and the width 12 is as follows.
It is said that the larger the G1, 12 and the smaller the G2 11, the better.

However, increasing the air gap G1 increases the loss of the shaded coil 1 and increasing the reactive current of the excitation coil, and decreasing the width 11 has the disadvantage that magnetic saturation of the main magnetic flux produced by the excitation coil begins earlier. Increasing 12 also leads to narrowing 10, which is generally dealt with by making the gap G2, which is not subject to other constraints, as small as possible.

However, reducing the gap G2 is most closely related to the surface roughness of the armature, and the minimum finished surface roughness possible from the viewpoint of mass production technology is limited to 1 μm, and is usually several μm.

Furthermore, in this case, due to the polishing technique, the gap G1. It is normal to process G2 in the same way.

Even if the finished surface roughness of the armature surface is close to 1 μm, if the circumferential armature surface is flat, there will still be a problem that the holding force will decrease and whine will occur for the following reasons. Ta.

In other words, each contact surface is finished with a surface roughness of nearly 1 μm, but when attached to individual electromagnetic contactors, the attachment and the connection state with the load are not uniform, and therefore the contact surface The armature surface is 100 mm due to uneven contact etc.
This is due to the fact that it is not working effectively.

In order to remove this, it is necessary to perform surface matching work for each electromagnetic contactor.

However, it is not desirable to incorporate manual labor into the manufacturing process of mass-produced products.

A way to completely eliminate the whirring is to use a DC type electromagnet for operating the electromagnetic contactor and convert the AC power to DC via a rectifier. Not only does this require additional equipment, which makes the entire device more complex and costly, but the inductance of the excitation coil suppresses the rise of the excitation current, which causes a decrease in the attractive force at areas where the electromagnet stroke is large. Therefore, it is difficult to use it generally.

FIG. 2 specifically shows an example of a conventional AC electromagnet of the type shown in FIG. 1B.

In FIG. 2, the AC electromagnet is made up of a movable iron core 3 made by laminating U-shaped electric iron plates (for example, silicon steel plates) and crimping them together with rivets 2, and having both leg end surfaces as armature surfaces 3a and 3b. A fixed iron core 4, which is made by laminating letter-shaped electric iron plates and integrating them by caulking rivets 2, and having the end surfaces of both legs 4a and 4b as armature surfaces 4al and 4bt, respectively, and the leg 4a.
The main component is an excitation coil 5 that is inserted into the excitation coil 5.

Two grooves are provided in each of the armature surfaces 4 at and 4 bl, and the shaded coil 1 is fitted into these grooves by press-fitting or the like.

The armature surfaces 3a and 3b and the armature surfaces 4a1 and 4b1 are made to be on the same plane, and have a surface roughness of 1 μm.
It is polished to a thickness of between several micrometers.

When the AC electromagnet configured in this manner is used as an operating electromagnet for an electromagnetic contactor or the like, there is a risk that the holding force may decrease and whirring may occur as described above.

Therefore, the purpose of this invention is to obtain an AC electromagnet with stable holding force without using any special equipment or processing technology.

According to the present invention, this purpose is to provide a fixed core made of laminated U-shaped electrical steel plates, a movable core made of stacked U-shaped electrical steel plates facing the fixed core, and a movable core made of laminated U-shaped electrical steel plates, which are attached to the fixed core. In the alternating current electromagnet, the excitation coil is provided with an excitation coil and a shaded coil attached to the armature surface of the fixed core. This is achieved by forming a concavo-convex portion having a slight step over the entire armature surface.

The area of the convex portion on the armature surface is preferably 30 to 70% of the original area of the armature surface.

Embodiments of this invention will be described in detail below based on the drawings.

3 to 5 are perspective views of different embodiments of the AC electromagnet according to this invention.

In FIG. 3, the AC electromagnet according to the present invention includes a movable iron core 13 whose armature surface has a surface roughness of 1 μm to several μm, similar to the conventional example, and a fixed iron core 14 which is an improvement over the conventional example. ing.

Both leg armature surfaces 1 of the fixed core 14 to which the shaded coil 1 is attached
4a1 and 14b have recesses 14 parallel to the stacking direction.
a2 and 14b2 are provided (therefore, the rest becomes a convex portion).

The remaining convex portions of the contact surfaces 14al and 14b1 are on the same plane, and are polished to a surface roughness of 1 μm to several μm.

Although not shown, an excitation coil is fitted to the leg portion 14a (or may be 14b) (see FIG. 3).
.

In the embodiment shown in FIG. 4, protrusions 13 al and 13 bl are provided on the armature surfaces 13 a and 13 b of both legs of the movable core 13 .

The convex portions 13al and 13bl are flush with each other and have a surface roughness of 1 μm to several μm.

The fixed iron core 14 and the excitation coil (not shown) are similar to those in the conventional example.

Furthermore, in the embodiment shown in FIG.
3a2 and 13b2 are provided (therefore, the rest are convex portions).

The remaining convex portions of the armature surfaces 13a and 13b are flush with each other and have a surface roughness of 1 μm to several μm.

The fixed iron core 4 and the excitation coil (not shown) are constructed in the same manner as in the conventional example.

In the above three types of AC electromagnets, the recesses 14a2, 14b2 and 13a2, 13 in FIG. 3 and FIG.
Depth of b2 and convex portions 13 a t, 13 b in Fig. 4
The height of 1 only needs to be small, and according to the inventor's experiments, Q
, 5 mm is appropriate, and in any of the above cases, the contact area with respect to the original area of the armature surface (in Figs. 3 and 5, the contact area of the armature surface 14 at, 14 bl: 13a, 13
From b to recess 14 a2, 14 b2: 13 a2, 1
．． 3 Area excluding b2, in Fig. 4 convex portion 13 al,
It has been demonstrated that a ratio of 30% to 70% (area of 13 bl) is good.

Figure 6 shows the excitation voltage ExV obtained by the inventor's experiment.
The relationship between and holding force HF is shown.

As shown in Figure 6, the contact area is 100% (although the actual contact area is approximately 80-100% depending on the roughness of the armature surface).
become.

The following is based on the apparent contact area. ), the curve (
1) is 60-70%, and curve (2) is 30-40%.
At %, curve (3) was obtained, at 20% curve (4) was obtained, and at 10%, curve (5) was obtained.

As is clear from the figure, curves (2) and (3) are curves (
1) has a larger holding force, while curves (4) and 5
The holding force is small.

This is because in the case of conventional models in which the entire surface of the armature of the movable and fixed picture iron cores is polished to a finished surface roughness in the range of 1 μm to several μm, the opposing armature surfaces are flat. Contact between the armature surfaces is not good due to uneven contact between the surfaces, but when the armature surface is made uneven as in the present invention, the number of places that come into contact with the other armature surface increases and the gap is also reduced overall. This is because magnetic saturation occurs quickly if the upper contact area is reduced to less than about 20% of the original contact area, although the magnetic flux becomes easier to pass through.

As described above, according to this invention, there is a fixed core formed by laminating U-shaped electrical steel plates, a movable core made by stacking U-shaped electrical steel plates facing the fixed core, and In an AC electromagnet including an excitation coil attached to an iron core and a shaded coil attached to an armature surface of the fixed iron core,
The holding force of the AC electromagnet is improved by forming unevenness on the armature surface of at least one of the fixed iron core or the movable iron core, which is parallel to the stacking direction of the electric iron plates and has a slight step over the entire armature surface. .

Conversely, it is possible to provide a smaller AC electromagnet with the same holding force.

[Brief explanation of the drawing]

Figures 1A and B are front views of main parts of different figures of conventional AC electromagnets, Figure 2 is a perspective view of an example of a conventional AC electromagnet, and Figures 3 to 5 are each of AC electromagnets according to this invention. FIG. 6, which is a perspective view of a different embodiment, is a diagram showing the relationship between excitation voltage (ExV) and holding force (HF) of a conventional AC electromagnet and an AC electromagnet according to the present invention. 1...Shaded coil, 3, 13...Movable core, 4, 14...Fixed core, 5--Exciting coil, 13a, 13b, 14 al. 14b1...Archive surface, 13 a 1.13 b
1""' convex part, 13a2゜13b2, 14a2, 14
b2... Concavity.

Claims (2)

[Scope of utility model registration request] (1) A fixed iron core formed by laminating U-shaped electrical iron plates, a movable iron core formed by laminating U-shaped electric iron plates facing the fixed iron core, an excitation coil attached to the fixed iron core, and the In an AC electromagnet equipped with a shaded coil attached to the armature surface of a fixed core, at least one of the fixed core or the movable core has a small amount of light applied to the armature surface parallel to the stacking direction of the electric iron plates over the entire armature surface. An alternating current electromagnet characterized by forming an uneven part having a step. (2) Utility model registration The AC electromagnet according to claim 1, wherein the area of the convex portion on the armature surface is 30 to 70% of the original area of the armature surface. .