WO2020084829A1 - Electromagnet, electromagnetic switch, and method of manufacturing electromagnet - Google Patents

Abstract

An electromagnet (10) comprises: a movable core (20); a fixed core (30) disposed opposite the movable core (20); and a drive coil (70) wound around the fixed core (30). One of the movable core (20) and the fixed core (30) is provided with, on a surface opposing the other core, a spacer (22) which is a single plate of austenitic stainless steel and which is obtained by processing a thin plate of JIS-standard 2B material or JIS-standard 2D material. The spacer (22) and the cores (20, 30) are welded together by means of a welding portion (Y) which is disposed on at least one of the spacer (22) and the cores (20, 30) and which has a protruding shape with respect to the other.

Description

Electromagnet, electromagnetic switch, and method of manufacturing electromagnet

The present application relates to an electromagnet, an electromagnetic switch, and a method for manufacturing an electromagnet.

The conventional electromagnet is one in which the movable iron core is attracted to the fixed iron core by the energization of the current, and the two iron cores are separated by the de-energization. In particular, in an electromagnet that is driven by a direct current or a current obtained by rectifying an alternating current, residual magnetization may occur in the iron core, and even if the energization is released, the two iron cores may not be separated from each other. In order to avoid this, an example is disclosed in which a thin plate made of a non-magnetic metal is bonded to at least one contact surface of a movable iron core or a fixed iron core by brazing as a residual magnetism prevention spacer (for example, refer to Patent Document 1).

Japanese Utility Model Publication No. 58-46412

In the electromagnet disclosed in Patent Document 1, when the current capacity of the electric circuit to be opened and closed increases, the contacts of the electric circuit also increase and the opening and closing force of the electromagnet also increases. To increase the opening / closing force of the electromagnet, it is sufficient to increase the iron core.However, when brazing the residual magnetism prevention spacer, it is necessary to heat the iron core until the temperature of the iron core exceeds the melting point of the brazing material. The larger the size, the longer the heating time and the worse the productivity.

Also, if a low-melting-point silver wax is used to shorten the heating time, the price of the brazing material itself is high, which causes a problem of increasing the manufacturing cost of the product.

The present application discloses a technique for solving the above problems, and an object thereof is to provide an electromagnet, an electromagnetic switch, and a method for manufacturing an electromagnet that have high productivity and can be produced at low cost. To do.

The electromagnet disclosed in the present application is
With a movable iron core,
A fixed iron core arranged to face the movable iron core,
An electromagnet having a drive coil wound around the fixed iron core,
One of the movable iron core or the fixed iron core,
On the surface facing the other iron core, a spacer made by processing a thin plate which is a single plate of austenitic stainless steel and is a JIS standard 2B material or a JIS standard 2D material,
The spacer and the iron core are provided on at least one of the spacer and the iron core, and are welded and fixed to each other by a welding portion having a convex shape with respect to the other.

Further, the electromagnetic switch disclosed in the present application,
The electromagnet,
A fixed contact integrally formed with the fixed iron core;
It is provided with a movable contact integrally formed with the movable core, the movable contact being in contact with and separated from the fixed contact in association with the driving of the movable core.

Further, the manufacturing method of the electromagnet disclosed in the present application is
A protrusion provided on at least one of the spacer or the iron core is brought into contact with the other, and the spacer and the iron core are sandwiched by a pair of electrodes and energized between the electrodes in a state of being pressurized to form the welded portion. It has a welding process to do.

According to the electromagnet, the electromagnetic switch, and the method for manufacturing the electromagnet disclosed in the present application, a non-magnetic thin plate-shaped spacer or iron core for preventing magnetism remaining in the fixed iron core and the movable iron core after the energization of the electromagnet is stopped. Since a plurality of protrusions are provided on at least one side and a current can be passed through the protrusions to weld the spacer and the iron core at a time, it is expected that the time for joining the iron core and the spacer will be significantly shortened and the productivity is high.

Moreover, since auxiliary materials such as silver solder for joining are not required, the cost of joining can be reduced.

FIG. 3 is a sectional view of the electromagnetic switch according to the first embodiment. FIG. 3 is a sectional view of the electromagnet according to the first embodiment. FIG. 5 is a view of the movable core according to the first embodiment as viewed from the spacer side. FIG. 3 is a plan view of a spacer before welding according to the first embodiment and a cross-sectional view of a main part thereof. FIG. 9 is a two-sided view of a fixed core according to the second embodiment. FIG. 11 is a view of a fixed iron core according to a third embodiment as seen from a spacer side. FIG. 11 is a diagram of a fixed iron core according to a fourth embodiment as viewed from a spacer side. FIG. 9 is a two-sided view showing a modified example of the movable core according to the second embodiment. FIG. 9 is a diagram showing an arrangement example of another protrusion according to the second embodiment. It is a figure which shows the point which positions a movable iron core and a spacer before welding using the positioning jig by Embodiment 5. FIG. 16 is a flowchart showing a process of welding a spacer and a movable iron core according to the fifth embodiment. It is a figure which shows the dimensional relationship of the positioning jig and spacer by Embodiment 5, and is a figure which shows the state after positioning completion and before welding. FIG. 19 is a diagram showing a state in which energization for welding according to the fifth embodiment is finished and welding is completed, but the electrodes are still applying pressure. It is a figure which shows the other example of the positioning jig by Embodiment 5.

Embodiment 1.
Hereinafter, the electromagnet, the electromagnetic switch, and the method for manufacturing the electromagnet according to the first embodiment will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of the electromagnetic switch 100.
The electromagnetic switch 100 includes an electromagnet 10, a fixed contact 40, and a movable contact 50.
The electromagnetic switch 100 opens and closes the movable contact 50 with respect to the fixed contact 40 by the operation of the electromagnet 10.

FIG. 2 is a sectional view of the electromagnet 10.
The electromagnet 10 is wound around the movable iron core 20, the fixed iron cores 30a and 30b, and the fixed iron cores 30a and 30b, and the drive coils 70a and 70b that drive the movable iron core 20 so that the movable iron core 20 can be moved toward and away from the fixed iron cores 30a and 30b. With. In the following description, the fixed iron core 30 simply refers to both the fixed iron core 30a and the fixed iron core 30b, and similarly, the drive coil 70 refers to both the drive coil 70a and the drive coil 70b.

The spacers 22a and 22b for preventing the magnetism remaining in the fixed iron core 30 and the movable iron core 20 after the power supply to the electromagnet 10 is stopped are attached to the surface of the movable iron core 20 facing the fixed iron core 30. In the following description, the term “spacer 22” simply refers to both the spacer 22a and the spacer 22b. The fixed iron core 30 is a set of two with the drive coil 70 attached, and is fixed to the base plate 33.

When a current is applied to the drive coils 70, opposite magnetic fields are generated in the two drive coils 70. That is, when the drive coil 70a attached to the left fixed iron core 30a generates a magnetic field upward in the drawing on the fixed iron core 30a, the drive coil 70b attached to the right fixed iron core 30b faces the fixed iron core 30b downward in the drawing. Generate a magnetic field.

Then, the magnetic flux generated upward in the left fixed iron core 30a passes through the spacer 22a installed on the left side of the movable iron core 20 and reaches the movable iron core 20, and the magnetic flux moves from the left side to the right side inside the movable iron core 20. Flowing toward. The magnetic flux reaching the right side of the movable iron core 20 passes through the spacer 22b and reaches the right fixed iron core 30b, and further the magnetic flux flows from the upper side to the lower side of the right fixed iron core 30b.

The magnetic flux that has reached the lower portion of the right fixed iron core 30b flows to the right side of the base plate 33, which is also made of a magnetic material, and flows from the right side of the base plate 33 to the left side. Then, the magnetic flux that has reached the left side of the base plate 33 flows to the lower part of the fixed iron core 30a and returns to the original position. When such a magnetic path is formed, the movable iron core 20 is attracted to the fixed iron core 30.
Then, as shown in FIG. 1, the movable contact 50 integrally molded or held with the movable iron core 20 and the resin molded product 25 (insulator) interlocks with the driving of the movable iron core 20 and the upper housing 55 (insulation). The electric circuit is closed by contacting the fixed contact 40 fixed to the object.

After that, when the current of the drive coil 70 is cut off, the magnetic flux generated from the drive coil 70 disappears. Here, when there is no air gap between the movable iron core 20 and the fixed iron core 30, coercive force of the materials of the movable iron core 20 and the fixed iron core 30 causes residual magnetism in both iron cores, and the resin molding 25 The repulsive force of the spring 27 provided between the lower housing 34 and the lower housing 34 cannot overcome the magnetic attraction force remaining in the fixed iron core 30 and the movable iron core 20, and the opening operation cannot be performed.

On the other hand, by providing the spacer 22 for preventing the residual magnetism of the non-magnetic material as in the present application, the portion where the spacer 22 is present is considered to be equivalent to the air gap on the magnetic circuit. A reverse magnetic field is applied to both iron cores over the range, and the effect that the residual magnetic flux becomes almost zero is obtained.

Then, the spring 27 integrated with the movable iron core 20 pushes up the movable iron core 20 that has lost the attractive force, so that the movable contact 50 integrated with the movable iron core 20 via the resin molded product 25 is moved from the fixed contact 40. They will be separated and the electric circuit will be opened.

In this way, by turning ON / OFF the current to the drive coil 70, the movable contact 50 is opened and closed through the movement of the movable iron core 20, and the electric circuit is opened and closed.

FIG. 3 is a view of the movable iron core 20 viewed from the spacer 22 side, and shows a state in which the spacer 22 is welded and fixed to the movable iron core 20.
The spacer 22 is made of a non-magnetic metal material, and is cut out from a plate material, for example. Rectangular spacers 22 are welded and fixed to the surface of the movable iron core 20 facing the fixed iron core 30 at a total of two sheets at each longitudinal end of the movable iron core 20.

As the spacer 22, a thin plate is used, but more preferably, a non-magnetic stainless material having good compatibility with the iron-based material of the movable iron core in welding, particularly a thin plate of austenitic stainless material such as SUS304 (STANLESS USED STEEL). It is better to use one that has been processed into a rectangular shape by press punching or the like.

In the pressing process, burrs are generally generated, and if the burrs are large, the burrs are peeled off by the impact of the opening / closing operation after the product is finished, and they are caught as foreign matter between the movable iron core and the fixed iron core, and thus the electromagnet becomes It may interfere with the operation. Therefore, the half blanking method is used as a burr-free press working method. Further, as a processing method other than the press processing, for example, laser processing can be used.

Here, the following points are important as the function of the spacer 22. That is, not only is the non-magnetic material necessary for the opening operation of the electromagnet 10 to be performed normally, but the impact when the movable core 20 and the fixed core 30 collide with each other during the closing operation of the electromagnet 10 is repeated. However, the strength is such that the movable core 20 does not come off.

As shown in FIG. 3, in order to secure the joining strength, the spacers 22 are provided at six locations per one circle by welding portions Y having a circular shape with a diameter of about 3 mm to 5 mm and a convex shape in the direction of the movable iron core 20. It is fixed to the movable iron core 20 by welding. The six welds Y are arranged near the corner of the spacer 22 at four places, and the remaining two are at the midpoints of the two welds Y provided at both ends of the long side of the spacer 22, respectively. It is arranged.

When the movable iron core 20 and the fixed iron core 30 are closed, the spacer 22 arranged between the movable iron core 20 and the fixed iron core 30 receives an impact due to the collision of the two. However, as described above, by arranging a large number of welded portions Y, the impact is distributed to the welded portions Y at six places, and the number of opening / closing operations is increased from 5 million times to 10 million times by the long-term use of the electromagnetic switch 100. Even if it reaches, it is considered that the spacer 22 does not peel off from the movable iron core 20 due to fatigue fracture near the welded portion Y.

According to our research, regarding the strength of the welded portion Y, if the strength difference between the portion once melted by welding and the original portion is large, the portion where the strength is changed by the impact at the closing operation of the electromagnet 10 It has been confirmed that stress is concentrated in the area where fatigue failure easily occurs.

That is, even with SUS304 material, the hardness of the JIS (Japan Industrial Standards) 1 / 2H material that has been adjusted in hardness, or the material that has been adjusted to a hardness of more than that, will cause the weld Y to open and close less than 5 million times. The peeling of the spacer 22 due to fatigue fracture was confirmed.

On the other hand, it was confirmed that the JIS standard 2B material, which has not been subjected to hardness conditioning, can withstand the opening and closing test of 5 million to 10 million times. That is, a JIS standard 2D material having a hardness equal to or lower than that of the 2B material or a hot rolled material has a high fatigue strength and is equal to or higher than the JIS standard 1 / 4H tempered material. It was found that the material whose hardness was adjusted was inferior in fatigue strength and was not suitable for this application.

On the other hand, regarding the function as a non-magnetic material, an austenitic stainless steel material such as SUS304 material changes its crystal structure from austenite to martensite by cold working, and further changes the arrangement of impurities. Therefore, it is known that it changes to a magnetic material although it is weak.

If the spacer 22 is magnetized, the effect of suppressing the residual magnetization of the movable iron core 20 and the fixed iron core 30, which is the original purpose, will be halved, and the opening operation of the movable iron core 20 may be hindered. In that sense as well, it is necessary to avoid using a material that has been tempered to increase the hardness of SUS304.

Similarly, the austenitic stainless steel material changes from a non-magnetic material by changing the crystal structure from austenite to martensite when the part that was once melted by welding is cooled and returns to solid, and the arrangement of impurities is changed. It is known that it changes to a magnetic material although it is weak. Therefore, it is desirable that the welded portion be as small as possible, and by providing the small welded portions Y at a plurality of locations in a dispersed manner as in the first embodiment, the welding strength as a whole and the magnetic characteristics of the non-magnetic material can be improved. It becomes possible to make them compatible.

The movable iron core 20 with the welded spacers 22 will be rusted as it is, so rust-proof plating is performed. Zn (zinc) plating is desirable if only the movable iron core 20 is present. However, since the spacer 22 made of SUS is integrated, Zn plating is not well formed on the surface of SUS. On the other hand, first, a method of welding the SUS spacer 22 to the movable iron core 20 plated with Zn can be considered, but it is known that the welding strength is reduced due to the influence of the plating.

Therefore, after the spacer 22 is welded to the movable iron core 20, the Ni (nickel) strike plating treatment is performed, and then the Zn chromate plating treatment is performed. Also, since the plating is applied, good plating processing can be performed.

FIG. 4A is a plan view of the spacer 22 before welding.
4B is a cross-sectional view of a main part of FIG. 4A. FIG. 4A is a diagram showing an arrangement of protrusions 24 provided on the spacer 22 before welding. FIG. 4B is a view showing a cross section of the protrusion 24 and a portion AA which is the vicinity thereof.
The protrusion 24 is provided at the same position as the arrangement of the welded portion Y. As can be seen from the AA cross-sectional view showing the configuration of the protrusion 24, the protrusion 24 has a concave portion formed on the left side portion of the plate and a convex portion formed on the right side portion of the plate by the length H within the range of φD. Each of them is formed in a spherical shape having a constant radius.

This spherical shape is formed, for example, by pressing a punch into a die with a punch having a hemispherical projection and a die having a hemispherical hollow shape, sandwiching a SUS304 plate in a press machine. As an example of these shapes, it was confirmed that φD is preferably about 2 mm to 5 mm and H is preferably about 0.3 mm to 1.5 mm when the thickness t of the plate is in the range of 0.3 mm to 1.5 mm.

Here, the method for welding the spacer 22 and the movable iron core 20 is that the spacer 22 and the movable iron core 20 are sandwiched by a pair of flat plate-shaped electrodes, and the projections 24 and the movable iron core 20 are in contact with each other. Pressurize. Further, by supplying a large current between the electrodes via the protrusions 24, heat is concentrated at the tips of the protrusions 24, and the tips of the protrusions 24 and a part of the movable iron core 20 with which the protrusions 24 contact are melted, Weld and join both.

ㆍ It is possible to energize only once regardless of the number of protrusions 24. The pressing force at this time is in the range of 0.2 kN to 2 kN per protrusion 24, though it depends on the plate thickness. The energizing current is 2 kA to 5 kA per protrusion. Further, the energization time is in the range of 15 msec to 60 msec.

It has been confirmed that when a large current is applied with a design in which the distance between the protrusions 24 is short, the melted portions are pulled by each other due to the Lorentz force and move, resulting in long protrusions. This portion does not contribute to the welding strength and, at worst, is removed by the impact of opening and closing and becomes a foreign substance. In the configuration of the first embodiment, for example, if this foreign matter is sandwiched between the spacer 22 and the fixed iron core 30, the attraction force between the iron cores at the time of closing the pole will be reduced, and the opening / closing operation of the electromagnet 10 will be hindered. There is a fear. Therefore, in order to prevent the above-mentioned long protrusion-shaped portion from occurring, it is desirable that the distance between the protrusions 24 be 10 mm or more.

Also, the resistance welding method of welding without a protrusion is generally used, but it is necessary to perform welding by sandwiching the welded parts one by one using a thin electrode with a diameter of about several mm. When this is applied to the case where a plurality of welded portions Y are provided as described above, the steps of first aligning the welded portions and then energizing by sandwiching them with electrodes are repeated a plurality of times for the number of welded portions. As a result, all welding takes time, and when welding the second and subsequent welds, the current spills into the welds that were welded before and the current in the portion to be welded decreases, resulting in insufficient welding. There is a risk that

On the other hand, according to the welding method described in the first embodiment, the spacer 22 and the movable iron core 20 are sandwiched by the pair of flat-plate-shaped electrodes larger than the spacer 22 to energize, thereby eliminating the need for positioning the electrodes. . Further, since a method is adopted in which pressure is applied in the state where the protrusion 24 and the movable iron core 20 are in contact with each other, and a large current is passed between the movable iron core 20 and the spacer 22 main body through the protrusion 24, it is possible to apply the current once. It is possible to generate a plurality of welded portions Y, which is advantageous in terms of productivity.

In the first embodiment, the projection 24 has a spherical shape as an example, but the shape is not limited to this and may be, for example, a conical shape. Also, an example is shown in which the shape of the back side of the protrusion 24 and the shape of the front side of the protrusion 24 are both spherical, but they do not necessarily have the same shape. For example, the surface is spherical and the back is conical. There is no problem even with a combination.

As points to note when forming the protrusions 24 on the spacer 22, it is desirable that the shapes and heights of the plurality of protrusions 24 be the same. If the heights of the protrusions 24 are not even, some protrusions 24 are in contact with the movable iron core 20, but other protrusions 24 are not in contact with each other, and the protrusions 24 that are not in contact cannot be welded. This is because there is a fear.

There are several types of power sources used for welding, but it is desirable to use a capacitor-type power source that performs constant-current control by inverter control when discharging the charges after storing the charges in the capacitor. With this power supply, a large amount of current can be passed in a short time, and the energy required for welding can be set to the minimum necessary, thus suppressing the generation of spatter-like foreign matter and the explosion during welding. However, stable welding is possible.

Further, in the first embodiment, the example in which the protrusion 24 is provided on the spacer 22 side has been shown, but it is not always necessary to provide it on the spacer 22 and, conversely, the protrusion may be provided on the movable iron core 20 side. Even in that case, the welding procedure is as described above and there is no change.

According to the electromagnet 10, the electromagnetic switch 100, and the method of manufacturing the electromagnet according to the first embodiment, a non-magnetic thin plate shape that prevents the magnetism remaining in the fixed iron core 30 and the movable iron core 20 after the power supply to the electromagnet 10 is stopped. Since a plurality of protrusions 24 can be provided on the spacer 22 and the protrusions 24 can be welded to the movable iron core 20 at one time, it is expected that the time for the joining process will be significantly shortened and the productivity is high.

Moreover, since auxiliary materials such as silver solder for joining are not required, the cost of joining can be reduced.

Embodiment 2.
Hereinafter, the electromagnet, the electromagnetic switch, and the method for manufacturing the electromagnet according to the second embodiment will be described with reference to the drawings, focusing on the points different from the first embodiment.
FIG. 5A is a view of the fixed iron core 230 as viewed from the spacer 232 side.
FIG. 5B is a side view of the fixed iron core 230.

In the first embodiment, the spacer 22 is welded to the movable iron core 20, but in the present embodiment, the spacer 232 is welded to the fixed iron core 230. As described above, needless to say, even if the spacer 232 is fixed by welding to the fixed iron core 230 side instead of the movable iron core 20, the same effect as that of the first embodiment is obtained. As shown in FIGS. 5A and 5B, when the spacer 232 is welded to the iron core (regardless of whether it is movable or fixed) via the protrusion, a convex shape remains in the welded portion Y, and between the spacer 232 and the iron core. Inevitably, a minute gap d remains. This also applies to the welded portion Y of the first embodiment.

In our experiment, it was confirmed that the thicker the spacer 232, the larger the gap d. It has been confirmed that when the gap d becomes large, the spacer 232 tends to peel off in the repeated opening / closing test of the electromagnet 10. Therefore, it is desirable to make the gap d as small as possible, preferably 0.2 mm or less, and more preferably 0.1 mm or less.

In the second embodiment, the number of welded portions Y is five. When the spacer 232 has a rectangular shape and the difference between the long side and the short side is relatively small, it is effective to dispose the welded portions Y on the four corners of the spacer 232 and diagonally. Further, for those having a small difference between the long side and the short side, the welded portions Y may be provided only at four positions at the four corners.

According to the electromagnet 10, the electromagnetic switch 100, and the method of manufacturing the electromagnet according to the second embodiment, the non-magnetic thin plate shape that prevents the magnetism remaining in the fixed iron core 230 and the movable iron core 20 after the power supply to the electromagnet 10 is stopped. Since a plurality of protrusions 24 can be provided on the spacer 232 and the protrusions 24 can be welded to the fixed iron core 230 at once, it is expected that the joining process will be significantly shortened.

8A and 8B are two views showing a modification of the movable core. FIG. 8A is a view of the fixed iron core 230B as seen from the side where the spacer is welded, and FIG. 8B is a side view of the fixed iron core 230B.

The example in which the protrusion 24 is provided on the spacer has been shown so far, but the protrusion 24B may be provided on the fixed core 230B side as shown in FIGS. 8A and 8B. Generally, since the spacer is a thin plate, it is easier to process the protrusion than the iron core. However, at the time of welding, it may be advantageous to provide a protrusion on the iron core side when the melting state on the iron core side is poor. Needless to say, even if the protrusion is provided on the iron core side, welding can be performed by adjusting the welding conditions.

9A, 9B, and 9C are diagrams showing examples of arrangement of other protrusions.
FIG. 9A is a plan view of the spacer 232C.
FIG. 9C is a view of the fixed iron core 230C viewed from the side where the spacer 232C is welded.
FIG. 9B is a diagram showing a state in which the spacer 232C is welded to the fixed iron core 230C.
As shown in FIG. 9A, FIG. 9B, and FIG. 9C, the same welding can be performed even if the protrusions 24C and 24B are provided on both the spacer 232C and the fixed iron core 230C.

In this example, three protrusions 24C1 out of a total of six protrusions are provided on the spacer 232C, and the remaining three protrusions 24C2 are arranged on the fixed iron core 230C side at positions that are the apexes of the triangles respectively, and after welding. , All the welded portions Y have a rectangular arrangement. In addition, by changing the heights of the protrusions 24C1 and 24C2, at the time of installation, three-point support of the higher height is provided, and it is expected that the spacer 232C before welding will have improved stability in the installed state.

Embodiment 3.
Hereinafter, the electromagnet, the electromagnetic switch, and the method for manufacturing the electromagnet according to the third embodiment will be described with reference to the drawings, focusing on the differences from the first and second embodiments.
FIG. 6 is a view of the fixed iron core 330 viewed from the spacer 332.
The outer peripheral shape of the contact surface of the fixed iron core 330 is circular, and the spacer 332 is configured in a circular shape having a center point O which is the same as the outer periphery of the fixed iron core 330, corresponding to the circular shape.

Furthermore, the welds Y are provided at three positions which are the vertices of an equilateral triangle centered on the center point O. If the number of welded portions Y = the number of protrusions before welding is set to three, even if the height of the protrusions 24 varies, the contact between the fixed iron core 330 and the spacer 332 is stable, so that each welded portion Y The contact resistance is stable, and stable energization and welding are possible. The same effect can be obtained even if the outer peripheral shape of the contact surface of the fixed iron core is quadrangular and the shape of the spacer is circular.

Fourth Embodiment
Hereinafter, the electromagnet, the electromagnetic switch, and the method of manufacturing the electromagnet according to the fourth embodiment will be described with reference to the drawings, focusing on the differences from the first to third embodiments.
FIG. 7 is a view of the fixed iron core 430 as seen from the spacer 432 side.
The outer peripheral shape of the contact surface of the fixed iron core 430 is rectangular, and the long side is considerably longer than the short side.
Then, the welded portions Y along the edges of the respective long sides are provided at three locations. Further, two welded portions Y adjacent to one long side edge and two welded portions Y on the same side in the longitudinal direction as the above two welded portions Y on the other long side edge. Another welded portion Y is provided at the intersection of the diagonal lines of the quadrangle with the welded portions Y at the four locations in total. Therefore, in FIG. 7, there are two welds Y arranged on the intersections of the diagonal lines, and there are a total of eight welds Y.

According to this configuration, even when the rectangular spacer 432 having a large aspect ratio is adopted, it is possible to securely fix the spacer 432 without impairing the welding strength of the fixed iron core 430 and the spacer 432.

Embodiment 5.
Hereinafter, a method of manufacturing the electromagnet according to the fifth embodiment will be described with reference to the drawings.
FIG. 10 is a diagram showing how to position the movable iron core 20 and the SUS spacer 22 before welding using the positioning jig 500.
FIG. 11 is a flow chart showing a process of welding the spacer 22 and the movable iron core 20.

First, on the welding surface 20s of the movable iron core 20, a positioning jig 500 having an opening 22k, which is obtained by hollowing out a portion where the spacer 22 is installed, is placed (step S001: positioning jig mounting step). Next, the two spacers 22 are fitted and arranged along the edge of the opening 22k. (Step S002: Spacer placement step). By arranging the spacers in this way, the position of the spacer 22 with respect to the movable iron core 20 can be accurately positioned.

FIG. 12 is a diagram showing a dimensional relationship between the positioning jig 500 and the spacer 22, showing a state after the completion of positioning and before welding.
The spacer 22 is pressed by the electrode 600, but the current is not yet applied.
FIG. 13 is a diagram showing a state where the energization for welding (step S003: welding process) is finished and the welding is completed, but the electrode 600 is still continuing to apply pressure.

12 and 13, the thickness of the portion of the spacer 22 excluding the conical protrusion 24B is hs, the height of the protrusion 24B provided on the spacer 22 before welding is ht, and the portion of the positioning jig 500 in contact with the spacer 22 is When the thickness is hj, the three dimensional relationships are set to satisfy ht <hj ≦ hs, so that a portion where the positioning jig 500 and the spacer 22 are in contact with each other before welding is left (hj-ht> 0). After that, it becomes possible to secure gap (hs + d−hj ≧ 0) in which the positioning jig 500 and the electrode 600 do not come into contact with each other, or are not pressurized even if they come into contact with each other. This enables the spacer 22 and the movable iron core 20 to be welded (step S003: welding step) with the positioning jig 500 installed, and the accuracy of the welding positions of both can be improved.

FIG. 14 is a diagram showing another example of the positioning jig.
The positioning jig 500B is obtained by cutting out both ends of the positioning jig 500 in the longitudinal direction at a portion including a part of the opening 22k described above. It is possible to improve the workability of installing the spacer 22 while maintaining the positioning accuracy of the spacer 22.

Note that, as described above, the protrusions may be provided on the fixed iron core side, and even when the protrusions are provided on both sides, the same effect can be obtained by setting the height of the protrusions to ht.

It is desirable to use an insulator for the positioning jigs 500 and 500B, and a resin such as glass epoxy or monomer cast nylon, or a material such as ceramic can be applied. In the present embodiment, the spacer has a rectangular shape, but it goes without saying that other shapes such as the above-mentioned circular shape are also applicable.

In each of the above-mentioned embodiments, SUS304 is exemplified as the material of the spacers 22, 232, 332, 432, but other austenitic stainless steel materials, for example, SUS300 series materials which are not yet tempered to increase hardness. It goes without saying that similar effects can be obtained if they are present.

Regarding the phenomenon in which austenitic stainless steel is magnetized by processing, it has been known from the material standpoint that the magnetization can be suppressed by increasing the nickel content, and although the material price rises, SUS305 with a high nickel content is used. , SUS316, etc., the magnetization due to processing can be greatly reduced.

Also, as the material of the iron core, the one having an integral shape is exemplified, but it goes without saying that the same effect can be obtained even if a magnetic steel sheet or a magnetic steel sheet such as a cold rolled steel sheet is laminated and integrated.

Although the present application describes various exemplary embodiments and examples, various features, aspects, and functions described in one or more of the embodiments are applicable to particular embodiments. However, the present invention is not limited to this, and can be applied to the embodiments alone or in various combinations. Therefore, innumerable variations not illustrated are envisioned within the scope of the technology disclosed herein. For example, it is assumed that at least one component is modified, added, or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

10 electromagnet, 20 movable iron core, 22, 232, 232C, 332, 432 spacer, 22k opening, 24, 24B, 24C1, 24C2 protrusion, 25 resin molded product, 30, 30a, 30b, 230, 230B, 330, 430 fixed Iron core, 33 base plate, 34 lower housing, 40 fixed contact, 50 movable contact, 55 upper housing, 70, 70a, 70b drive coil, 100 electromagnetic switch, 500, 500B positioning jig, 600 electrode, O center point, Y welding Part, d gap.

Claims (10)

With a movable iron core,
A fixed iron core arranged to face the movable iron core,
An electromagnet having a drive coil wound around the fixed iron core,
One of the movable iron core or the fixed iron core,
On the surface facing the other iron core, a spacer made by processing a thin plate which is a single plate of austenitic stainless steel and is a JIS standard 2B material or a JIS standard 2D material,
An electromagnet in which the spacer and the iron core are provided on at least one of the spacer and the iron core, and are welded and fixed to each other by a welding portion having a convex shape with respect to the other. The electromagnet according to claim 1, wherein the spacer has a rectangular shape, and the welded portions are arranged at a total of six positions, that is, four corners of the rectangle and two midpoints on a long side of the rectangle. The electromagnet according to claim 1, wherein the spacer has a circular shape, and the welded portions are provided at three positions which are apexes of a triangle having the same center point as the center point of the spacer. The spacer has a rectangular shape, and is the same in the longitudinal direction as two welded portions adjacent to one long side edge of the spacer and the two welded portions provided on the other long side edge. The electromagnet according to claim 1, further comprising two welded portions on the side and another welded portion disposed on an intersection of diagonal lines of a quadrangle having the four welded portions as vertices. An electromagnet according to any one of claims 1 to 4,
A fixed contact insulated and connected to the fixed iron core,
An electromagnetic switch comprising: a movable contact, which is insulatively connected to the movable iron core, which comes into contact with and separates from the fixed contact in association with driving of the movable iron core. It is a manufacturing method of the electromagnet according to any one of claims 1 to 4,
A protrusion provided on at least one of the spacer or the iron core is brought into contact with the other, and the spacer and the iron core are sandwiched by a pair of electrodes and energized between the electrodes in a state of being pressurized to form the welded portion. Method for manufacturing an electromagnet having a welding step of: The method of manufacturing an electromagnet according to claim 6, further comprising a spacer disposing step of positioning the spacer on a welding surface of the iron core by a positioning jig. 8. The method of manufacturing an electromagnet according to claim 7, wherein the positioning jig has an opening portion in which a portion where the spacer is installed is hollowed out. If the thickness of the portion of the spacer excluding the protrusion is hs, the height of the protrusion is ht, and the thickness of the positioning jig is hj, then ht <hj ≦ hs,
The method of manufacturing an electromagnet according to claim 8, wherein the welding step is performed with the positioning jig installed. The said protrusion is arrange | positioned at each 3 each at the said spacer and the said iron core, and each 3 protrusions are arrange | positioned at the position used as the apex of a triangle. A method for producing the described electromagnet.

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