CN112889122B

CN112889122B - Electromagnet, electromagnetic shutter, and method for manufacturing electromagnet

Info

Publication number: CN112889122B
Application number: CN201980069192.2A
Authority: CN
Inventors: 庄野一弘; 猿渡秀宪; 山口博; 竹本智彦; 曾田昇吾
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2018-10-25
Filing date: 2019-06-18
Publication date: 2022-10-28
Anticipated expiration: 2039-06-18
Also published as: JPWO2020084829A1; TW202016958A; TWI688975B; WO2020084829A1; KR102427376B1; JP7002673B2; CN112889122A; KR20210049934A

Abstract

The electromagnet (10) is provided with: a movable iron core (20); a fixed core (30) disposed opposite to the movable core (20); and a driving coil (70) wound around the fixed core (30), wherein the core of one of the movable core (20) and the fixed core (30) has a spacer (22) formed by processing a single plate of austenitic stainless steel and a sheet of a JIS 2B material or a JIS 2D material on a surface facing the core of the other, and the spacer (22) and the cores (20, 30) are welded and fixed to each other by a weld (Y) provided at least one of the spacer (22) and the cores (20, 30) and having a convex shape with respect to the other.

Description

Electromagnet, electromagnetic switch, and method for manufacturing electromagnet

Technical Field

The present application relates to an electromagnet, an electromagnetic shutter, and a method of manufacturing the electromagnet.

Background

In the conventional electromagnet, a movable core is attracted to a fixed core by energization of a current, and the two cores are separated by release of energization. In particular, in an electromagnet that is driven by a direct current or by an alternating current after rectification, residual magnetization occurs in the cores, and even when the energization is released, a state in which the two cores are not separated may occur. In order to avoid this state, an example is disclosed in which a thin plate of a non-magnetic metal is welded and joined as a residual magnetism prevention spacer to a contact surface of at least one of the movable core and the fixed core (see, for example, patent document 1).

Patent document 1: japanese Kokai publication Sho-58-46412

Disclosure of Invention

In the electromagnet disclosed in patent document 1, if the current capacity of the electric circuit is increased for opening and closing, the contact point of the electric circuit is also increased, and the opening and closing force of the electromagnet is also increased. In order to increase the opening/closing force of the electromagnet, the core may be increased, but when the residual magnetism preventing spacer is welded, the core needs to be heated until the temperature of the core exceeds the melting point of the welding material, and therefore if the core is increased, the heating time is increased, which causes a problem of deterioration in productivity.

Further, if a silver solder having a low melting point is used to shorten the heating time, the price of the solder itself is high, which causes an increase in the production cost of the product.

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

The electromagnet disclosed in this application has:

a movable iron core;

a fixed core disposed to face the movable core; and

a driving coil wound around the fixed core,

the core of one of the movable core and the fixed core has a spacer obtained by processing a single plate of austenitic stainless steel and a sheet of a JIS 2B material or a JIS 2D material on a surface facing the core of the other,

the spacer and the core are welded and fixed to each other by a weld portion provided at least one of the spacer and the core and having a convex shape with respect to the other.

Further, an electromagnetic switch disclosed in the present application includes:

the electromagnet;

a fixed contact integrally formed with the fixed core; and

and a movable contact point which is in contact with or separated from the fixed contact point in linkage with the driving of the movable iron core and is integrally formed with the movable iron core.

The method for manufacturing an electromagnet disclosed in the present application includes a welding step of bringing a projection provided on at least one of the spacer and the core into contact with the other, and energizing a pair of electrodes while the spacers and the core are sandwiched between the electrodes and pressed, thereby forming the welded portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the electromagnet, the electromagnetic switch, and the method for manufacturing the electromagnet disclosed in the present application, since the plurality of projections are provided on at least one of the nonmagnetic thin plate-shaped spacer and the core that prevent residual magnetism from remaining in the fixed core and the movable core after the stop of energization of the electromagnet, and the spacer and the core can be simultaneously welded by flowing current through the projections, it is expected that the time for the step of joining the core and the spacer is significantly shortened, and productivity is high.

In addition, since an auxiliary material for bonding such as silver solder is not required, cost reduction of bonding can be achieved.

Drawings

Fig. 1 is a sectional view of an electromagnetic switch according to embodiment 1.

Fig. 2 is a cross-sectional view of an electromagnet according to embodiment 1.

Fig. 3 is a view of the movable core according to embodiment 1 viewed from the spacer side.

Fig. 4 is a plan view and a main part sectional view of a pad before welding according to embodiment 1.

Fig. 5 is a two-dimensional view of a fixed core according to embodiment 2.

Fig. 6 is a view of the fixed core according to embodiment 3 as viewed from the spacer side.

Fig. 7 is a view of the fixed core according to embodiment 4 as viewed from the spacer side.

Fig. 8 is a two-dimensional view showing a modification of the movable core according to embodiment 2.

Fig. 9 is a diagram showing another example of arrangement of the projections according to embodiment 2.

Fig. 10 is a view showing a principle of positioning the movable core and the spacer before welding by using the positioning jig according to embodiment 5.

Fig. 11 is a flowchart showing a step of welding the gasket and the movable core according to embodiment 5.

Fig. 12 is a diagram showing a dimensional relationship between the positioning jig and the spacer according to embodiment 5, and is a diagram showing a state after positioning is completed and before welding.

Fig. 13 is a diagram showing a state in which energization for welding according to embodiment 5 is completed and welding is completed, but the electrode is still being pressurized.

Fig. 14 is a diagram showing another example of the positioning jig according to embodiment 5.

Detailed Description

Embodiment 1.

Next, an electromagnet, an electromagnetic switch, and a method for manufacturing the electromagnet according to embodiment 1 will be described with reference to the drawings.

Fig. 1 is a sectional view of an electromagnetic shutter 100.

The electromagnetic switch 100 is composed of 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 has: a movable core 20;

fixed cores

30a, 30b; and driving

coils

70a and 70b wound around the

fixed cores

30a and 30b and capable of driving the movable core 20 to be in contact with or separated from the

fixed cores

30a and 30 b. In the following description, when simply referred to as the fixed core 30, the fixed core 30a and the fixed core 30b are both referred to, and similarly, when referred to as the driving coil 70, the driving coil 70a and the driving coil 70b are both referred to.

On the surface of the movable core 20 facing the fixed core 30, there are attached

spacers

22a and 22b that prevent residual magnetism from remaining in the fixed core 30 and the movable core 20 after the energization of the electromagnet 10 is stopped. In the following description, the term "gasket 22" refers to both the gasket 22a and the gasket 22 b. The fixed iron cores 30 are fixed to the base plate 33 in 2 sets in a state where the driving coil 70 is attached.

If a current is applied to the driving coils 70, magnetic fields of opposite directions are generated at the 2 driving coils 70. That is, when the driving coil 70a attached to the left fixed core 30a causes the fixed core 30a to generate a magnetic field with the paper surface facing upward, the driving coil 70b attached to the right fixed core 30b causes the fixed core 30b to generate a magnetic field with the paper surface facing downward.

The magnetic flux generated upward in the left fixed core 30a reaches the movable core 20 through the spacer 22a provided on the left side of the movable core 20, and flows from the left side to the right side in the movable core 20. The magnetic flux reaching the right side of the movable core 20 reaches the fixed core 30b on the right side through the spacer 22b, and the magnetic flux flows downward from above the fixed core 30b on the right side.

Then, the magnetic flux that reaches the lower portion of the right fixed core 30b flows through the right side of the base plate 33 also made of a magnetic material, and the magnetic flux flows from the right side to the left side of the base plate 33. The magnetic flux reaching the left side of the base plate 33 flows to the lower portion of the fixed core 30a and returns to the original path. If the magnetic path is formed as described above, the movable core 20 is attracted by the fixed core 30.

As shown in fig. 1, the movable contact 50, which is integrally molded with or held by the movable core 20 via the resin molding 25 (insulator), is brought into contact with the fixed contact 40 fixed to the upper case 55 (insulator) in conjunction with the driving of the movable core 20, thereby closing the electric circuit.

Then, if the current of the driving coil 70 is turned off, the magnetic flux generated from the driving coil 70 disappears. Here, when there is no air gap between the movable core 20 and the fixed core 30, residual magnetism is generated in both cores by the coercive force of the raw materials of the movable core 20 and the fixed core 30, and the repulsive force of the spring 27 provided between the resin molded article 25 and the lower case 34 cannot overcome the attractive force generated by the residual magnetism remaining in the fixed core 30 and the movable core 20, and open circuit operation cannot be performed.

On the other hand, as shown in the present application, by providing the spacer 22 for preventing residual magnetism of the nonmagnetic material, the portion where the spacer 22 is present is regarded as being equivalent to the air gap in the magnetic path, and therefore, the coercive force of the two core materials is exceeded, and a reverse magnetic field is applied to the two cores, and an effect that the residual magnetic flux becomes substantially zero is obtained.

Then, the spring 27 integrated with the movable core 20 pushes up the movable core 20 that has lost the attraction force, and the movable contact 50 integrated with the movable core 20 via the resin molded article 25 is separated from the fixed contact 40, whereby the electric circuit is opened.

As described above, the movable contact 50 is opened and closed by the ON/OFF of the current to the driving coil 70 through the operation of the movable core 20, and the electric circuit is opened and closed.

Fig. 3 is a view of the movable core 20 viewed from the spacer 22 side, and shows a state where the spacer 22 is welded and fixed to the movable core 20.

The liner 22 is made of a non-magnetic metal material, and is cut out of a plate material, for example. The rectangular spacers 22 are provided at 1 piece at each end of the movable core 20 in the longitudinal direction, and welded and fixed to the surface of the movable core 20 facing the fixed core 30 by 2 pieces in total.

A thin plate is USED as the spacer 22, but it is more preferable to use a member obtained by processing a thin plate of a nonmagnetic STAINLESS material having good compatibility when welded to an iron-based material of the movable core, particularly an austenitic STAINLESS material such as SUS304 (standing USED STEEL), into a rectangular shape by press punching or the like.

Further, in the press working, burrs are generally generated, and if the burrs are large, the burrs are peeled off by the impact of the opening and closing operation after the product is produced, and may be sandwiched between the movable core and the fixed core as foreign matter, thereby hindering the operation as the electromagnet. Therefore, the half-flat method is used as a press working method in which burrs are not generated. As a processing method other than press processing, for example, laser processing or the like can be used.

Here, the following points are important as the function of the spacer 22. That is, it is needless to say that the nonmagnetic material is required to be of a degree necessary to normally perform the opening operation of the electromagnet 10, and the strength is required to be of a degree that the movable core 20 does not peel off from the fixed core 30 even if the impact at the time of collision between the movable core 20 and the fixed core 30 is repeated at the time of the closing operation of the electromagnet 10.

As shown in fig. 3, in order to ensure the bonding strength, the spacer 22 is welded and fixed to the movable core 20 by a welding portion Y which is circular in 6 portions of 1 piece and has a diameter of about 3mm to 5mm and is convex in the direction of the movable core 20. The 6-spot welded portions Y are arranged so that 4 spots are arranged close to the corners of the pad 22, and the remaining 2 spots are arranged at the midpoints of the 2-spot welded portions Y provided at both ends of the long side of the pad 22.

When the movable core 20 and the fixed core 30 are closed, the spacer 22 disposed between the movable core 20 and the fixed core 30 receives an impact caused by a collision therebetween. However, as described above, by arranging a plurality of welding portions Y, it is considered that the gasket 22 is not separated from the movable core 20 by fatigue fracture in the vicinity of the welding portions Y even when the number of times of opening and closing reaches 500 to 1000 ten thousand times by long-term use of the electromagnetic shutter 100 due to impact distribution to the welding portions Y at 6 locations.

Further, according to our study, when the difference in strength between the portion that is temporarily melted by welding and the original portion is large, it is confirmed that the stress concentrates on the portion where the strength is changed by the impact at the time of closing operation of the electromagnet 10, and fatigue failure is likely to occur.

That is, even for the SUS304 material, it was confirmed that the peeling of the liner 22 due to the fatigue fracture of the welded portion Y occurred when the opening/closing frequency was 500 ten thousand or less for the 1/2H material of the JIS (Japanese Industrial Standards) standard adjusted in hardness or the material adjusted in hardness or more.

On the other hand, if a JIS 2B material, on which no adjustment of hardness is performed, is used, it can be confirmed that the opening and closing test can be performed 500 to 1000 ten thousand times. That is, if the material is a 2D material or a hot rolled material in JIS standard having a hardness equal to or less than that of a 2B material, the fatigue strength is high, and a material having a hardness equal to or more than that of a 1/4H adjusted material in JIS standard has a poor fatigue strength, and is found to be unsuitable for the present application.

On the other hand, regarding the function as a nonmagnetic material, it is known that an austenite stainless material such as SUS304 material is weakened from the nonmagnetic material to a magnetic material by cold working to change the crystal structure from austenite to martensite and change the arrangement of impurities.

If the spacer 22 is magnetized, the effect of suppressing the residual magnetization of the movable core 20 and the fixed core 30, which is the original purpose, is reduced by half, and there is a possibility that the opening operation of the movable core 20 is hindered. This should be avoided by using a material to which adjustment for increasing the hardness of SUS304 is applied.

Similarly, it is known that when a portion of an austenitic stainless steel material which is temporarily melted by welding is cooled and returned to a solid state, the crystal structure is changed from austenite to martensite, and the arrangement of impurities is changed, and the like, so that the non-magnetic material becomes weak and the magnetic material is changed. Therefore, it is preferable that the welding portion is as small as possible, and as in embodiment 1, by providing small welding portions Y in a plurality of positions in a dispersed manner, the overall welding strength and the magnetic properties of the nonmagnetic material can be satisfied at the same time.

In this case, the movable core 20 to which the spacer 22 is welded is rusted, and therefore, a rust-proof plating treatment is performed. In the case of the movable core 20 alone, zn (zinc) plating is preferable, but since the spacer 22 made of SUS is integrated, the Zn plating is not favorably formed on the surface of SUS. On the other hand, first, a method of welding the SUS spacer 22 to the Zn-plated movable core 20 is also considered, but it is known that the welding strength is reduced by the influence of plating.

Therefore, by performing Ni (nickel) impact plating after welding the spacer 22 to the movable core 20 and then performing Zn chromate plating, the surface of the spacer 22 made of SUS is also plated while the rust prevention function of Zn plating is generated, and thus a favorable plating treatment can be performed.

Fig. 4A is a plan view of the liner 22 before soldering.

Fig. 4B is a main portion sectional view of fig. 4A.

Fig. 4A is a diagram showing the arrangement of the bumps 24 before welding, on which the spacers 22 are provided. Fig. 4B isbase:Sub>A view showingbase:Sub>A cross section of the projection 24 andbase:Sub>A portionbase:Sub>A-base:Sub>A in the vicinity thereof.

The projections 24 are provided at the same positions as the arrangement of the welding portions Y. As is apparent from the sectional viewbase:Sub>A-base:Sub>A showing the structure of the projection 24, the projection 24 is formed inbase:Sub>A spherical shape havingbase:Sub>A constant radius in the range of Φ D, withbase:Sub>A concave portion formed in the left portion of the plate by the length H andbase:Sub>A convex portion formed in the right portion of the plate.

The spherical shape is formed by pressing a punch into a cavity with a plate of SUS304 therebetween, for example, by the punch having a hemispherical protrusion and the cavity having a hemispherical depression in a press. As an example of these shapes, it was confirmed that in the range of the plate thickness t of 0.3mm to 1.5mm, it is preferable that φ D is about 2mm to 5mm, and H is about 0.3mm to 1.5 mm.

Here, as a method of welding the spacer 22 and the movable core 20, first, the spacer 22 and the movable core 20 are sandwiched by a pair of electrodes in a flat plate shape, and the projections 24 and the movable core 20 are pressed against each other in a state of being in contact with each other. Then, a large current is passed between the electrodes through the projection 24, so that heat is concentrated on the tip of the projection 24, and the tip of the projection 24 and a part of the movable core 20 with which the projection 24 is in contact are melted, and the two are welded and joined.

The number of times of energization is not dependent on the number of the projections 24, and may be 1 time. The pressurizing force at this time is related to the sheet thickness, but ranges from 0.2kN to 2kN for each 1 of the projections 24. In addition, the energizing current is 2kA to 5kA for each 1 bump. The energization time is in the range of 15msec to 60 msec.

In addition, if a large current is applied in the design in which the distance between the projections 24 is short, a phenomenon is observed in which the melted portions are pulled and moved by the lorentz force, and long, convex portions are generated. This portion does not affect the welding strength, and in the worst case, is removed by the impact of opening and closing to become foreign matter. In the configuration of embodiment 1, if the foreign matter is sandwiched between the spacer 22 and the fixed core 30, for example, the attraction force between the cores at the time of closing is reduced, which may hinder the opening and closing operation of the electromagnet 10. Therefore, in order not to generate the long convex-like portion described above, it is preferable that the distance between the protrusions 24 is opened to be greater than or equal to 10mm.

In addition, although resistance welding is generally used to perform welding without providing a projection, welding needs to be performed with a welding portion interposed between every 1 part using a thin electrode having a diameter of about several mm. If the present application is applied to the case where a plurality of welded portions Y are provided as described above, the step of positioning the welded portions is performed first, and then the step of applying current by electrode clamping is repeated a plurality of times corresponding to the number of welded portions. As a result, it takes time to weld the entire area, and when welding the 2 nd portion and the following portions, the current may be returned to the welding portion welded before the second portion and the current of the portion to be welded may be reduced, which may result in insufficient welding.

On the other hand, according to the welding method described in embodiment 1, the pad 22 and the movable core 20 are sandwiched between a pair of flat electrodes larger than the pad 22 and energized, and thus positioning of the electrodes is not necessary. Further, since the movable core 20 and the spacer 22 main body are pressed with the projection 24 and the movable core 20 in contact with each other, and a large current flows between the movable core 20 and the spacer 22 main body through the projection 24, a plurality of welded portions Y can be formed by 1-time energization, which is advantageous in terms of productivity.

In embodiment 1, the shape of the projection 24 is spherical, but the present invention is not limited to this, and may be conical, for example. Further, although the shape of the back surface side of the projection 24 and the shape of the front surface side of the projection 24 are both spherical, the shapes do not necessarily have to be the same, and there is no problem with a combination of, for example, a spherical surface and a conical surface.

As a point of attention when the pad 22 forms the protrusions 24, it is preferable that the plurality of protrusions 24 are uniform in shape and height. If the height of the protrusions 24 is not uniform, one of the protrusions 24 comes into contact with the movable core 20, but the other protrusions 24 do not come into contact with each other, and there is a possibility that the non-contact protrusions 24 cannot be welded.

There are several types of power sources used in welding, but a capacitor type power source in which constant current control is performed by inverter control when electric charge is discharged after electric charge is accumulated in a capacitor is particularly preferable. According to this power supply, a large current can be passed in a short time, and the energy required for welding can be set to a required minimum, so that stable welding can be performed while suppressing the generation of spatter-like foreign matter and the occurrence of explosion during welding.

In embodiment 1, the example in which the protrusion 24 is provided on the spacer 22 side is shown, but the protrusion does not necessarily need to be provided on the spacer 22, and conversely, the protrusion may be provided on the movable core 20 side. In this case, the welding procedure is also unchanged as described above.

According to the electromagnet 10, the electromagnetic shutter 100, and the method of manufacturing the electromagnet in accordance with embodiment 1, since the plurality of projections 24 are provided on the nonmagnetic thin plate-like spacer 22 that prevents residual magnetism remaining in the fixed core 30 and the movable core 20 after the stop of energization of the electromagnet 10, and the projections 24 can be welded to the movable core 20 at the same time, the time for the joining process is expected to be significantly shortened, and productivity is high.

Furthermore, since an auxiliary material for bonding such as silver solder is not required, the cost of bonding can be reduced.

Embodiment 2.

Next, an electromagnet, an electromagnetic switch, and a method for manufacturing an electromagnet according to embodiment 2 will be described mainly focusing on differences from embodiment 1 with reference to the drawings.

Fig. 5A is a view of the fixed core 230 viewed from the spacer 232 side.

Fig. 5B is a side view of the fixed core 230.

In embodiment 1, the spacer 22 is welded to the movable core 20, but in this embodiment, the spacer 232 is welded to the fixed core 230. As described above, the spacer 232 is not fixed to the movable core 20 by welding but fixed to the fixed core 230 side by welding, and it is needless to say that the same effect as that of embodiment 1 is obtained. As shown in fig. 5A and 5B, when the spacer 232 is welded to the core via the projection (regardless of the movement and fixation), the projection shape remains at the welded portion Y, and it is not avoided that a minute gap d remains between the spacer 232 and the core. This is also the same for the welded portion Y of embodiment 1.

In our experiment, it was confirmed that the larger the thickness of the spacer 232, the larger the gap d becomes. If the gap d is increased, it is confirmed that the spacer 232 tends to be easily peeled off in the opening and closing repetition test of the electromagnet 10. Therefore, the clearance d is preferably as small as possible, and is preferably set to 0.2mm or less, and more preferably 0.1mm or less.

In embodiment 2, the number of the welded portions Y is 5. In the case where the pad 232 has a rectangular shape and the difference between the long side and the short side is small, it is effective to provide the welded portion Y at the 4 corners and the diagonal line of the pad 232. In addition, in the case where the difference between the long side and the short side is small, the welded portions Y may be provided only in 4 portions at 4 corners.

According to the electromagnet 10, the electromagnetic shutter 100, and the method of manufacturing the electromagnet according to embodiment 2, the plurality of projections 24 are provided on the nonmagnetic thin plate-like spacer 232 that prevents residual magnetism remaining in the fixed core 230 and the movable core 20 after the stop of energization of the electromagnet 10, and the projections 24 can be welded to the fixed core 230 at the same time, so that a considerable time reduction in the joining process is expected.

Fig. 8A and 8B are two-dimensional views showing modifications of the movable core. Fig. 8A is a view of the fixed core 230B as viewed from the side where the pad is welded, and fig. 8B is a side view of the fixed core 230B.

Although the example has been described so far in which the projection 24 is provided on the spacer, the projection 24B may be provided on the fixed core 230B side as shown in fig. 8A and 8B. In general, since the spacer is a thin plate, the protrusion process is easier than that of the core. However, in the case where the degree of melting of the core side is poor in the welding, it may be advantageous to provide a projection on the core side. It is needless to say that the projection provided on the core side can be welded by adjusting the welding conditions.

Fig. 9A, 9B, and 9C are views showing other examples of the arrangement of the projections.

Fig. 9A is a top view of the gasket 232C.

Fig. 9C is a view of the fixed core 230C as viewed from the side where the spacers 232C are welded.

Fig. 9B is a diagram showing a state in which the spacer 232C is welded to the fixed core 230C. As shown in fig. 9A, 9B, and 9C, the same welding can be performed by providing the projections 24C and 24B on both the spacer 232C and the fixed core 230C.

In this example, 3 projections 24C1 out of the total 6 projections are provided on the spacer 232C, and the remaining 3 projections 24C2 are arranged at positions each having a 3-angle vertex on the fixed core 230C side, and after welding, all the welded portions Y are arranged in a rectangular shape. Further, by changing the heights of the bumps 24C1 and 24C2, 3 points having a high height are supported during installation, and improvement in stability of the pad 232C before soldering in the installed state can be expected.

Embodiment 3.

Next, an electromagnet, an electromagnetic switch, and a method for manufacturing an electromagnet according to embodiment 3 will be described, focusing on differences from embodiments 1 and 2, with reference to the drawings.

Fig. 6 is a view of the fixed core 330 viewed from the spacer 332 side.

The outer peripheral shape of the contact surface of the fixed core 330 is circular, and the spacer 332 is configured in a circular shape having one smaller turn from the center point O, which is the same as the outer periphery of the fixed core 330, in accordance with the shape.

The welding portion Y is provided at 3 positions that are vertexes of each of regular triangles centered on the center point O. If the number of the welding portions Y = the number of projections before welding and 3 locations are provided, the contact between the fixed core 330 and the spacer 332 is stable even when the height of the projection 24 varies, and therefore the contact resistance of each welding portion Y is stable, and welding can be performed by stable current supply. The outer peripheral shape of the contact surface of the fixed core is a quadrangle, and the shape of the spacer is a circle, which has the same effect.

Embodiment 4.

Next, an electromagnet, an electromagnetic switch, and a method for manufacturing an electromagnet according to embodiment 4 will be described, focusing on differences from embodiments 1 to 3, with reference to the drawings.

Fig. 7 is a view of the fixed core 430 viewed from the spacer 432 side.

The outer peripheral shape of the contact surface of the fixed core 430 is a rectangle, and the long side is much longer than the short side.

The welded portions Y along the edges of the respective long sides are provided at 3 locations. Further, another 1-part welded part Y is provided, and the 1-part welded part Y is disposed at an intersection of diagonal lines of a 4-sided polygon having as vertexes the welded parts Y of a total of 4 parts of the welded parts Y of 2 parts adjacent to the edge of one long side and the welded parts Y of 2 parts of the edge of the other long side which are on the same side in the longitudinal direction as the welded parts Y of the 2 parts. Thus, in fig. 7, the weld Y disposed at the intersection of the diagonal lines is 2 locations, and there are 8 total weld Y locations.

According to this configuration, even when the spacer 432 having a rectangular shape with a high aspect ratio is used, the fixing of the spacer 432 can be secured without impairing the welding strength between the fixed core 430 and the spacer 432.

Embodiment 5.

Next, a method for manufacturing an electromagnet according to embodiment 5 will be described with reference to the drawings.

Fig. 10 is a view showing a step of positioning the movable core 20 and the SUS spacer 22 before welding by using a positioning jig 500.

Fig. 11 is a flowchart showing a process of welding the spacer 22 and the movable core 20.

First, a positioning jig 500 having an opening 22k formed by cutting through a portion where the spacer 22 is provided is mounted on the welding surface 20S of the movable core 20 (step S001: positioning jig mounting step). Next, 2 pieces of the spacers 22 are fitted and arranged so as to extend along the edges of the opening 22k (step S002: spacer arranging step). If the spacers are arranged as described above, the position of the spacer 22 with respect to the movable core 20 can be positioned with high accuracy.

Fig. 12 is a diagram showing a dimensional relationship between the positioning jig 500 and the gasket 22, and shows a state after positioning is completed and before welding.

The pad 22 is pressurized by the electrode 600 but is not yet energized.

Fig. 13 shows a state in which the energization for welding (step S003: welding process) is completed and welding is completed, but the electrode 600 is still pressurized.

In fig. 12 and 13, if the thickness of the portion of the gasket 22 other than the conical projection 24B is hs, the height of the projection 24B provided on the gasket 22 before welding is ht, and the thickness of the portion of the positioning jig 500 in contact with the gasket 22 is hj, then 3 dimensional relationships are set to ht < hj ≦ hs, whereby the portion of the positioning jig 500 in contact with the gasket 22 (hj-ht > 0) can be retained before welding, and the gap (hs + d-hj ≧ 0) in which the positioning jig 500 and the electrode 600 do not contact or are not pressurized even if they contact is secured after welding. Accordingly, even in a state where the positioning jig 500 is still provided, the welding of the spacer 22 and the movable core 20 can be performed (step S003: welding step), and the accuracy of the welding position of the both can be improved.

Fig. 14 is a view showing another example of the positioning jig.

The positioning jig 500B is obtained by cutting and opening both longitudinal end portions of the positioning jig 500 at a portion including a part of the opening 22 k. The workability of installing the spacer 22 can be improved while maintaining the positioning accuracy of the spacer 22.

Further, as described above, the projection may be provided on the fixed core side, and in the case where both of them are provided, the same effect can be obtained if the height of the projection is ht.

An insulator is preferably used for the positioning jigs 500, 500B, and a resin such as glass epoxy resin or cast nylon, or a material such as ceramic can be applied. In the present embodiment, the case where the spacer is rectangular is exemplified, but it is needless to say that the spacer can be applied to other shapes such as the above-mentioned circular shape.

In the above embodiments, SUS304 is exemplified as the material of the

spacers

22, 232, 332, 432, but it goes without saying that the same effect is obtained if the material is other austenite stainless material, for example, SUS 300-numbered material, and the adjustment for increasing the hardness is not performed.

It is known that magnetization of austenitic stainless steel materials by processing can be suppressed by increasing the content of nickel in the material surface, and the material price increases, but if SUS305, SUS316, or the like, which contains a large amount of nickel, is selected, magnetization due to processing can be significantly reduced.

Further, although the core material is shown as a single-piece structure, it is needless to say that the same effects are obtained by using a structure in which magnetic steel sheets such as electromagnetic steel sheets or cold-rolled steel sheets are laminated and integrated.

While various exemplary embodiments and examples have been described in the present application, the various features, modes and functions described in 1 or more embodiments are not limited to the application to the specific embodiments, and may be applied to the embodiments alone or in various combinations. Therefore, numerous modifications not illustrated are conceivable within the technical scope disclosed in the specification of the present application. Examples of the case include a case where at least 1 component is modified, added, or omitted, and a case where at least 1 component is extracted and combined with the components of the other embodiments.

Description of the reference symbols

10 electromagnets, 20 movable iron cores, 22, 232C, 332, 432 pads, 22k openings, 24B, 24C1, 24C2 bulges, 25 resin molding products, 30a, 30B, 230B, 330, 430 fixed iron cores, 33 base plate, 34 lower case, 40 fixed contact, 50 movable contact, 55 upper case, 70a, 70B drive coil, 100 electromagnetic shutter, 500B positioning jig, 600 electrode, O center point, Y welding part, d gap.

Claims

1. An electromagnet having:

a movable iron core;

a fixed core disposed to face the movable core; and

a driving coil wound around the fixed core,

the core of one of the movable core and the fixed core has a spacer obtained by processing a thin plate, which is a single plate of an austenitic stainless steel and has a hardness equal to or less than that of a 2B material in JIS standards, on a surface facing the core of the other of the movable core and the fixed core,

2. The electromagnet of claim 1,

the pad is rectangular, and the welding parts are arranged at 6 positions in total of 2 positions of 4 corners of the rectangle and the midpoint of the long side of the rectangle.

3. The electromagnet of claim 1,

the pad has a circular shape, and the welding portions are provided at 3 positions that are apexes of a triangle having the same center point as the center point of the pad.

4. The electromagnet of claim 1,

the pad is rectangular and has 2 welded portions adjacent to an edge of one long side of the pad, 2 welded portions provided at an edge of the other long side and located on the same side in the longitudinal direction as the 2 welded portions, and 1 other welded portion arranged at an intersection of diagonal lines of a 4-sided figure having the 4 welded portions as vertexes.

5. An electromagnetic shutter, comprising:

the electromagnet of any one of claims 1 to 4;

a fixed contact insulated from the fixed core; and

and a movable contact point which is brought into contact with or separated from the fixed contact point in conjunction with driving of the movable core, and which is connected to the movable core in an insulated manner.

6. A method for manufacturing an electromagnet according to any one of claims 1 to 4,

the method of manufacturing an electromagnet includes a welding step of bringing the convex projection provided on at least one of the spacer and the core into contact with the other, and energizing a pair of electrodes while pressing the spacers and the core therebetween, thereby forming the welded portion.

7. The method of manufacturing an electromagnet according to claim 6,

in the welding step, the welding portion is formed by welding the gasket and the core by energizing the pair of electrodes through the protrusion in a state where the pair of electrodes sandwich the gasket and the core and melting a tip of the protrusion and a part of the gasket or the core with which the protrusion is in contact.

8. The method of manufacturing an electromagnet according to claim 6 or 7,

the method comprises a spacer arranging step of positioning the spacer on the welding surface of the iron core by a positioning jig.

9. The method of manufacturing an electromagnet according to claim 8,

the positioning jig has an opening portion formed by hollowing out a portion where the spacer is provided.

10. The method of manufacturing an electromagnet according to claim 9,

if the thickness of the part of the gasket except the bulge is set as hs, the height of the bulge is set as ht, and the thickness of the positioning clamp is set as hj, then ht < hj ≦ hs,

the welding process is performed in a state where the positioning jig is provided.

11. The method of manufacturing an electromagnet according to any one of claims 6, 7, 9, and 10,

the number of the projections is 3, and 3 projections are arranged at 3 angular positions serving as vertexes, respectively, of the spacer and the core.

12. The method of manufacturing an electromagnet according to claim 8,

13. A method of manufacturing an electromagnetic switch, the electromagnetic switch having:

an electromagnet manufactured by the method for manufacturing an electromagnet according to any one of claims 6 to 12;

a fixed contact insulated from the fixed core; and