JP7521296B2 - Electromagnetic Relay - Google Patents

Description

The present invention relates to an electromagnetic relay.

In electromagnetic relays, arcs can occur between the contacts. In such cases, the arcs can reduce the mechanical life of the electromagnetic relay. For this reason, for example, the electromagnetic relay disclosed in Patent Document 1 is equipped with a magnet that generates a magnetic field between the contacts. The magnet generates a magnetic field perpendicular to the direction in which the contacts face each other.

JP 2017-027892 A

In the above electromagnetic relay, the Lorentz force acts on the arc due to the magnetic field, stretching the arc toward the arc quenching space. This extinguishes the arc. To quickly extinguish the arc, it is preferable that the arc quenching space is large. However, expanding the arc quenching space can lead to an increase in the size of the electromagnetic relay. The object of the present invention is to quickly extinguish the arc in an electromagnetic relay while preventing the electromagnetic relay from becoming large.

According to one aspect of the present invention, there is provided an electromagnetic relay comprising a first contact, a second contact, and a magnet. The first contact includes a first surface. The second contact includes a second surface facing the first surface. The magnet generates a magnetic field between the first contact and the second contact. The first surface has a diameter larger than a diameter of the second surface. The first surface has a radius of curvature smaller than a radius of curvature of the second surface.

In the electromagnetic relay according to this embodiment, the distance between the first surface and the second surface increases as the distance from the center of the first surface increases. Therefore, the arc is stretched more than when the first surface is flat. In addition, the Lorentz force acting on the arc increases as the arc is stretched more. This makes it easier for the bright spot of the arc to move. This allows the arc to be quickly extinguished. In addition, because the above effects are obtained due to the shape of the first contact, it is possible to prevent the electromagnetic relay from becoming too large.

The first contact may have a diameter larger than that of the second contact. In this case, the distance between the ends of the first contact and the second contact is large. Thus, the arc is stretched more and is extinguished more quickly.

The magnet may generate a magnetic field for applying a Lorentz force to the arc generated between the first surface and the second surface. The distance between the first surface and the second surface may increase from the center of the first surface toward the direction of action of the Lorentz force. In this case, the arc moves in the direction of action of the Lorentz force, causing it to be significantly elongated. This allows the arc to be quickly extinguished.

The electromagnetic relay may further include a first mounting surface and a second mounting surface. A first contact may be attached to the first mounting surface. A second contact may be attached to the second mounting surface. The height from the second mounting surface to the second surface may be greater than the height from the first mounting surface to the first surface. In this case, the volume of the second contact is increased, thereby suppressing a rise in temperature of the second contact when current is applied.

The second contact may further include a second side located between the second surface and the second mounting surface. The angle between the second side and the second mounting surface may be an obtuse angle. In this case, the arc is more likely to move from the second contact to the second mounting surface. This allows the arc to be quickly extinguished.

The second surface may include a central portion and a peripheral portion. The peripheral portion may be located around the central portion. The height from the second mounting surface to the peripheral portion may be less than the height from the second mounting surface to the central portion. In this case, the arc is more likely to move from the second contact to the second mounting surface. This allows the arc to be quickly extinguished.

The present invention makes it possible to quickly extinguish arcs in an electromagnetic relay while preventing the electromagnetic relay from becoming too large.

FIG. 2 is a front cross-sectional view of the electromagnetic relay according to the embodiment. FIG. 2 is a front cross-sectional view of the electromagnetic relay in a closed state. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a side view of the first movable contact and the first fixed contact. FIG. 4 is a top view of the first movable contact. FIG. 4 is a cross-sectional view of a first movable contact. FIG. 13 is a side view of a first fixed contact and a first movable contact according to a first modified example. FIG. 11 is a side view of a first fixed contact and a first movable contact according to a second modified example. FIG. 11 is a cross-sectional view of an electromagnetic relay according to a modified example.

Below, an embodiment of an electromagnetic relay 1 according to one aspect of the present invention will be described with reference to the drawings. FIG. 1 is a front cross-sectional view of the electromagnetic relay 1. As shown in FIG. 1, the electromagnetic relay 1 includes a housing 2, a contact device 3, and a drive device 4.

When referring to the drawings, for ease of understanding, the upper side in FIG. 1 will be described as "upper", the lower side as "lower", the left side as "left", and the right side as "right". Additionally, the front side of the paper in FIG. 1 will be described as "front", and the back side as "rear". However, these directions are defined for the sake of convenience, and do not limit the arrangement direction of the electromagnetic relay 1.

The housing 2 is made of an insulating material such as resin. However, the housing 2 may be made of other materials such as ceramic. The contact device 3 is housed within the housing 2.

The contact device 3 includes a first fixed terminal 6, a second fixed terminal 7, a movable contact piece 8, and a movable mechanism 9. The first fixed terminal 6 and the second fixed terminal 7 extend in the direction in which the movable contact piece 8 moves. The first fixed terminal 6 and the second fixed terminal 7 are arranged at a distance from each other in the left-right direction. A portion of the first fixed terminal 6 and a portion of the second fixed terminal 7 protrude to the outside of the housing 2. A first fixed contact 10 is connected to the first fixed terminal 6. A second fixed contact 11 is connected to the second fixed terminal 7. The first fixed contact 10 and the second fixed contact 11 are arranged within the housing 2.

The movable contact piece 8 extends in the left-right direction. The movable contact piece 8 is disposed within the housing 2. A first movable contact 12 and a second movable contact 13 are connected to the movable contact piece 8. The first movable contact 12 faces the first fixed contact 10. The second movable contact 13 faces the second fixed contact 11. The first movable contact 12 is disposed at a distance from the second movable contact 13 in the left-right direction.

The movable contact piece 8 can move in a contact direction and a separation direction. The contact direction is the direction in which the movable contacts 12, 13 approach the fixed contacts 10, 11. The separation direction is the direction in which the movable contacts 12, 13 move away from the fixed contacts 10, 11. In this embodiment, the movable contact piece 8 can move in the up and down directions.

The movable mechanism 9 supports the movable contact piece 8. The movable mechanism 9 is provided so as to be movable between a closed position and an open position. When the movable mechanism 9 is in the closed position, the fixed contacts 10, 11 and the movable contacts 12, 13 come into contact with each other. When the movable mechanism 9 is in the open position, the fixed contacts 10, 11 and the movable contacts 12, 13 are separated from each other. The movable mechanism 9 includes a drive shaft 15 and a contact spring 16. The drive shaft 15 is connected to the movable contact piece 8. The drive shaft 15 extends in the vertical direction and penetrates the movable contact piece 8 in the vertical direction. The drive shaft 15 is provided so as to be movable in the vertical direction. The contact spring 16 biases the movable contact piece 8 in the contact direction.

The drive unit 4 includes a coil 21, a spool 22, a movable iron core 23, a fixed iron core 24, a yoke 25, and a return spring 26. The drive unit 4 uses electromagnetic force to move the movable contact piece 8 in the contact direction and the separation direction via the movable mechanism 9. The coil 21 is wound around the spool 22. The movable iron core 23 and the fixed iron core 24 are disposed within the spool 22. The movable iron core 23 is connected to the drive shaft 15. The movable iron core 23 can move in the vertical direction. The fixed iron core 24 is disposed opposite the movable iron core 23. The return spring 26 biases the movable iron core 23 in the separation direction.

The electromagnetic relay 1 shown in FIG. 1 is in an open state. In the open state, the movable contacts 12, 13 are separated from the fixed contacts 10, 11. When the coil 21 is energized, the magnetic force of the magnetic field generated by the coil 21 attracts the movable core 23 to the fixed core 24. As a result, the movable core 23 and the drive shaft 15 move in the contact direction against the biasing force of the return spring 26. As a result, as shown in FIG. 2, the movable contact piece 8 and the movable contacts 12, 13 move in the contact direction, and the movable contacts 12, 13 come into contact with the fixed contacts 10, 11. As a result, the electromagnetic relay 1 is in a closed state as shown in FIG. 2. After the movable contacts 12, 13 come into contact with the fixed contacts 10, 11, the drive shaft 15 moves further in the contact direction, compressing the contact spring 16.

When the current to the coil 21 is turned off, the movable core 23 and the drive shaft 15 move in the separation direction due to the biasing force of the return spring 26. This causes the movable contact piece 8 and the movable contacts 12, 13 to move in the separation direction, and the movable contacts 12, 13 are separated from the fixed contacts 10, 11 as shown in FIG. 1.

Figure 3 is a cross-sectional view taken along line III-III in Figure 1. As shown in Figure 3, the electromagnetic relay 1 is equipped with magnets 27 and 28. The magnets 27 and 28 are permanent magnets. However, one of the magnets 27 and 28 may be a yoke. The magnets 27 and 28 are positioned so that the bright point of the arc generated at the contacts 10-13 is moved in a predetermined direction by magnetic force.

As shown in FIG. 3, the magnets 27 and 28 generate a magnetic field B1 inside the housing 2. In FIG. 3, the two-dot chain arrow indicates the direction of the magnetic field B1. The magnets 27 and 28 generate a magnetic field B1 between the first movable contact 12 and the first fixed contact 10. The magnetic field B1 has a magnetic flux in a direction perpendicular to the direction in which the first movable contact 12 and the first fixed contact 10 face each other. The magnets 27 and 28 generate a magnetic field B1 between the second movable contact 13 and the second fixed contact 11. The magnetic field B1 has a magnetic flux in a direction perpendicular to the direction in which the second movable contact 13 and the second fixed contact 11 face each other. As a result, a Lorentz force acts on the arc generated at the contacts 10-13, and the bright point of the arc moves in the direction of the Lorentz force. The arc is also elongated in the direction of the Lorentz force.

In FIG. 3, the solid arrows F1 and F1' indicate the direction of the Lorentz force (hereinafter referred to as the "first Lorentz force") when the current flows in the positive direction. The positive direction means that the current flows from the first fixed terminal 6 through the movable contact piece 8 to the second fixed terminal 7. When the current flows in the positive direction, the bright spot of the arc generated between the first movable contact 12 and the first fixed contact 10 moves in the direction of the first Lorentz force F1. The bright spot of the arc generated between the second movable contact 13 and the second fixed contact 11 moves in the direction of the first Lorentz force F1'.

In FIG. 3, the dashed arrows F2 and F2' indicate the direction of the Lorentz force (hereinafter referred to as the "second Lorentz force") when the current flows in the reverse direction. The reverse direction means that the current flows from the second fixed terminal 7 through the movable contact piece 8 to the first fixed terminal 6. When the current flows in the reverse direction, the bright spot of the arc generated between the first movable contact 12 and the first fixed contact 10 moves in the direction of the second Lorentz force F2. The bright spot of the arc generated between the second movable contact 13 and the second fixed contact 11 moves in the direction of the second Lorentz force F2'.

Figure 4 is a side view of the first movable contact 12 and the first fixed contact 10. Figure 5 is a top view of the first movable contact 12. As shown in Figure 4, the first movable contact 12 has a diameter larger than the diameter of the first fixed contact 10. The movable contact piece 8 includes a first mounting surface 31. The first movable contact 12 is attached to the first mounting surface 31. The first fixed terminal 6 includes a second mounting surface 32. The first fixed contact 10 is attached to the second mounting surface 32.

As shown in Figs. 4 and 5, the first movable contact 12 includes a first surface 33 and a first side surface 34. The first surface 33 is disposed at the center of the first movable contact 12. The first side surface 34 is located between the first surface 33 and the first mounting surface 31. The first side surface 34 is disposed around the first surface 33. As shown in Fig. 5, the first side surface 34 is located radially outward of the first surface 33. The first side surface 34 is inclined with respect to the vertical and horizontal directions.

The first fixed contact 10 includes a second surface 35 and a second side surface 36. The second surface 35 is disposed at the center of the first fixed contact 10. The second side surface 36 is located between the second surface 35 and the second mounting surface 32. The second side surface 36 is disposed around the second surface 35. The second side surface 36 is located radially outward of the second surface 35. The second side surface 36 extends in the up-down direction.

The first surface 33 has a diameter D1 larger than a diameter D2 of the second surface 35. The first surface 33 has a radius of curvature R1 smaller than a radius of curvature R2 of the second surface 35. The second surface 35 may be flat. FIG. 6 is a cross-sectional view of the first movable contact 12. As shown in FIG. 6, a distance L1 between a plane P1 and the first surface 33 increases toward the radially outward direction of the first movable contact 12. The plane P1 is a horizontal imaginary plane passing through the apex of the first surface 33. A distance L2 between the plane P1 and the first side surface 34 increases toward the radially outward direction of the first movable contact 12.

The second surface 35 and the second side surface 36 face the first surface 33. The second surface 35 and the second side surface 36 are located directly above the first surface 33. That is, in a top view, the second surface 35 and the second side surface 36 overlap the first surface 33. The diameter D4 of the second side surface 36 is smaller than the diameter D3 of the first side surface 34. The diameter D4 of the second side surface 36 is smaller than the diameter D1 of the first surface 33. The second side surface 36 may be inclined in the up-down direction. In that case, the diameter D4 of the second side surface 36 described above may be the maximum value of the diameter of the second side surface 36. The diameter D3 of the first side surface 34 means the maximum value of the diameter of the first side surface 34.

The height H2 from the second mounting surface 32 to the second surface 35 is greater than the height H1 from the first mounting surface 31 to the first surface 33. When the second surface 35 is curved, the height H2 from the second mounting surface 32 to the second surface 35 means the maximum height from the second mounting surface 32 to the second surface 35. The height H1 from the first mounting surface 31 to the first surface 33 means the maximum height from the first mounting surface 31 to the first surface 33.

As described above, the magnets 27, 28 generate a magnetic field B1 between the first movable contact 12 and the first fixed contact 10. As a result, the first Lorentz force F1 acts on the arc generated between the first movable contact 12 and the first fixed contact 10. Note that the dashed line in FIG. 4 indicates the arc. The distance between the first surface 33 and the second surface 35 increases from the center of the first surface 33 toward the direction in which the first Lorentz force F1 acts.

In the electromagnetic relay according to this embodiment, the distance between the first surface 33 and the second surface 35 increases as the distance from the center of the first surface 33 increases in the direction of the first Lorentz force F1. Therefore, the arc is stretched more than when the first surface 33 is flat. In addition, as the arc is stretched more, the Lorentz force acting on the arc increases. This makes it easier for the bright spot of the arc to move. This allows the arc to be quickly extinguished. In addition, because the above effects are obtained due to the shape of the first movable contact 12, it is possible to prevent the electromagnetic relay 1 from becoming too large.

In addition, if the diameter of the first fixed contact 10 is smaller than the diameter of the first movable contact 12, the temperature of the first fixed contact 10 is likely to rise when electricity is applied. However, in this embodiment, the height H2 of the first fixed contact 10 is greater than the height H1 of the first movable contact 12. This increases the volume of the first fixed contact 10, thereby suppressing the temperature rise of the first fixed contact 10 when electricity is applied.

The second fixed contact 11 has a shape similar to that of the first fixed contact 10. The second movable contact 13 has a shape similar to that of the first movable contact 12. However, the second fixed contact 11 may have a shape similar to that of the first movable contact 12. The second movable contact 13 may have a shape similar to that of the first fixed contact 10. When the electromagnetic relay 1 has polarity, it is preferable that the contact that is the cathode has a larger diameter than the contact that is the anode.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

For example, the shape of the movable contact piece 8 may be changed. The first movable contact 12 and the second movable contact 13 may be integral with the movable contact piece 8. The first fixed contact 10 may be integral with the first fixed terminal 6. The second fixed contact 11 may be integral with the second fixed terminal 7. The number of movable contacts is not limited to two and may be more than two. The number of fixed contacts is not limited to two and may be more than two. The configuration of the movable mechanism 9 is not limited to that of the above embodiment and may be changed. The configuration of the drive device 4 is not limited to that of the above embodiment and may be changed.

The arrangement of the magnets 27, 28, or the arrangement of the magnetic field B1 produced by the magnets 27, 28 may be changed. The shapes of the first fixed contact 10 and the first movable contact 12 are not limited to those in the above embodiment, and may be changed. The shapes of the second fixed contact 11 and the second movable contact 13 are not limited to those in the above embodiment, and may be changed. For example, the fixed contacts 10, 11 may be made of multiple materials, or may be made of a single material. The movable contacts 12, 13 may be made of multiple materials, or may be made of a single material.

Figure 7 is a side view of the first fixed contact 10 and the first movable contact 12 according to the first modified example. As shown in Figure 7, the angle θ between the second side surface 36 of the first fixed contact 10 and the second mounting surface 32 may be an obtuse angle. In this case, the arc is more likely to move from the first fixed contact 10 to the second mounting surface 32. This allows the arc to be quickly extinguished.

Figure 8 is a side view of the first fixed contact 10 and the first movable contact 12 according to the second modified example. As shown in Figure 8, the second surface 35 may include a central portion 37, a peripheral portion 38, and a step portion 39. The central portion 37 is located at the center of the first fixed contact 10. The peripheral portion 38 is located around the central portion 37. The step portion 39 is located between the central portion 37 and the peripheral portion 38. The step portion 39 protrudes from the peripheral portion 38 toward the central portion 37. The height H4 from the second mounting surface 32 to the peripheral portion 38 is smaller than the height H3 from the second mounting surface 32 to the central portion 37. In this case, the arc is more likely to move from the first fixed contact 10 to the second mounting surface 32. This allows the arc to be quickly extinguished.

In the above embodiment, the first movable contact 12 is an example of the first contact, and the first fixed contact 10 is an example of the second contact. However, the first movable contact 12 may be an example of the second contact, and the first fixed contact 10 may be an example of the first contact. That is, the shapes of the first movable contact 12 and the first fixed contact 10 may be reversed from the above embodiment. In the first modification or the second modification, the shapes of the first movable contact 12 and the first fixed contact 10 may be reversed. Alternatively, in the first modification or the second modification, the first movable contact 12 may have the same shape as the first fixed contact 10.

The electromagnetic relay 1 according to the above embodiment is a so-called plunger-type electromagnetic relay. However, the electromagnetic relay may be of another type. For example, FIG. 9 is a cross-sectional view of an electromagnetic relay 1a according to a modified example. The electromagnetic relay 1a according to the modified example is a so-called hinge-type electromagnetic relay. The hinge-type electromagnetic relay 1a includes a housing 2a, a contact device 3a, and a drive device 4a. The drive device 4a includes a coil 21a, a spool 22a, a movable iron piece 23a, an iron core 24a, and a yoke 25a.

The coil 21a is wound around the spool 22a. The iron core 24a is disposed within the spool 22a. The movable iron piece 23a is attracted to the iron core 24a by the magnetic field generated by the coil 21a. A return spring (not shown) is attached to the movable iron piece 23a.

The contact device 3a includes a first terminal 6a, a second terminal 7a, a movable contact piece 8a, a fixed contact 10a, a movable contact 12a, and a card 9a. The first terminal 6a and the second terminal 7a protrude to the outside of the housing 2a. The fixed contact 10a is attached to the first terminal 6a. The movable contact piece 8a is connected to the second terminal 7a. The movable contact 12a is attached to the movable contact piece 8a. The movable contact 12a faces the fixed contact 10a. The card 9a is disposed between the movable iron piece 23a and the movable contact piece 8a. When the coil 21a is energized, the movable iron piece 23a is attracted to the iron core 24a and presses the card 9a. As a result, the card 9a presses the movable contact piece 8a. As a result, the movable contact 12a comes into contact with the fixed contact 10a. When the current to the coil 21a is released, the elastic force of the return spring causes the movable iron piece 23a to return to its original position. This releases the pressure on the movable contact piece 8a by the card 9a, and the elastic force of the movable contact piece 8a causes the movable contact piece 8a to return to its original position. This causes the movable contact 12a to move away from the fixed contact 10a.

The electromagnetic relay 1a is equipped with a magnet 27a. The magnet 27a generates a magnetic field between the movable contact 12a and the fixed contact 10a. As a result, a Lorentz force acts on the arc generated between the movable contact 12a and the fixed contact 10a. The movable contact 12a may have the same shape as the first fixed contact 10a in the above-mentioned embodiment. The fixed contact 10a may have the same shape as the first movable contact 12a in the above-mentioned embodiment. Alternatively, the movable contact 12a may have the same shape as the first movable contact 12a in the above-mentioned embodiment. The fixed contact 10a may have the same shape as the first fixed contact 10a in the above-mentioned embodiment.

The present invention makes it possible to quickly extinguish arcs in an electromagnetic relay while preventing the electromagnetic relay from becoming too large.

10 First fixed contact (second contact)
12 First movable contact (first contact)
27 magnet 31 first mounting surface 32 second mounting surface 33 first surface 36 second side surface 37 central portion 38 peripheral portion

Claims (6)

A fixed terminal,
a movable contact piece that is movable in a contact direction toward the fixed terminal and in a separation direction away from the fixed terminal;
a first contact provided on one of the fixed terminal and the movable contact piece and including a first surface;
a second contact provided on the other of the fixed terminal and the movable contact piece, the second contact including a second surface facing the first surface in the contact direction ;
a magnet that generates a magnetic field between the first contact and the second contact;
Equipped with
the first surface has a diameter greater than a diameter of the second surface;
the first surface has a radius of curvature smaller than a radius of curvature of the second surface;
Electromagnetic relay. The first contact has a diameter greater than a diameter of the second contact.
2. An electromagnetic relay as claimed in claim 1. the magnet generates a magnetic field for applying a Lorentz force to an arc generated between the first surface and the second surface;
a distance between the first surface and the second surface increases from a center of the first surface toward a direction in which the Lorentz force acts;
3. An electromagnetic relay according to claim 1 or 2. a first mounting surface to which the first contact is attached;
a second mounting surface to which the second contact is attached;
Further equipped with
A height from the second mounting surface to the second surface is greater than a height from the first mounting surface to the first surface.
4. An electromagnetic relay according to claim 1. the second contact further includes a second side located between the second surface and the second mounting surface;
the angle between the second side surface and the second mounting surface is an obtuse angle;
5. An electromagnetic relay according to claim 4. The second surface is
The center and
A peripheral portion located around the central portion;
Including,
A height from the second mounting surface to the peripheral portion is smaller than a height from the second mounting surface to the center portion.
5. An electromagnetic relay according to claim 4.

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