Patent Grant
11705292
This application claims priority to Japanese Patent Application No. 2021-101220, filed Jun. 17, 2021. The contents of that application are incorporated by reference herein in their entirety.
The present invention relates to an electromagnetic relay.
In an electromagnetic relay, an arc occurs at the contacts when the current is cut off. As the arc elevates the temperature of the contacts, the contacts may melt and generate a hot gas containing metal vapor. If the hot gas stays in the vicinity of the contacts, the insulation performance between the contacts is degraded, and the arc may reignite. In order to prevent the re-ignition of the arc, the electromagnetic relay disclosed in Japanese Unexamined Patent Application Publication No. 2016-24864 includes an arc-extinguishing space, a gas inflow space separate from the arc-extinguishing space, and a gas passage, all disposed in a case, for allowing the hot gas to escape from the arc-extinguishing space into the gas inflow space.
In the electromagnetic relay of Japanese Unexamined Patent Application Publication No. 2016-24864, the inlet and outlet of the gas passage are disposed in the vicinity of the contact. Thus, the hot gas easily returns to the contact through the gas passage. As the load capacity increases, the amount of hot gas returning to the vicinity of the contact also increases, which may cause the arc to reignite.
An object of the present invention is to reduce the possibility of re-ignition of an arc at a contact in an electromagnetic relay.
The electromagnetic relay according to one aspect of the present invention includes a first fixed terminal, a second fixed terminal, a movable contact piece, a case, a drive device, and a first magnet. The first fixed terminal includes a first fixed contact. The second fixed terminal includes a second fixed contact and is apart from the first fixed terminal. The movable contact piece includes a first movable contact facing the first fixed contact and a second movable contact facing the second fixed contact. The case includes an accommodation space where the first fixed contact, the second fixed contact, and the movable contact piece are accommodated, and a side wall covering the accommodation space in a first direction. The drive device moves the movable contact piece in moving directions including a direction in which the first movable contact approaches the first fixed contact and a direction in which the first movable contact separates from the first fixed contact. The first magnet is disposed laterally to the first fixed contact. The first magnet configured to extend an arc generated between the first fixed contact and the first movable contact in a second direction opposite to the first direction. The first fixed terminal includes a first end in the second direction. The first end of the first fixed terminal includes a tapered portion. The tapered portion is inclined from the first fixed contact toward the first magnet in the second direction, and at least partially overlaps with the first magnet when viewed from the moving directions of the movable contact piece. The case includes an arc extension space expanding in the second direction from the tapered portion and communicating with the accommodation space.
In the electromagnetic relay, an arc generated between the first fixed contact and the first movable contact is extended in the second direction. That is, the bright spot of the arc on the first fixed terminal moves to the first end. The bright spot of the arc that has moved to the first end is guided by the tapered portion at the first end, and easily moves to the back side of the first magnet, and also moves in the first direction. Thus, the arc can be significantly extended in the arc extension space expanding in the first direction from the tapered portion, so that the arc can be quickly cut off. As a result, the possibility of re-ignition of the arc generated between the first fixed contact and the first movable contact can be reduced.
The first fixed terminal may include a first external connecting portion protruding from the side wall in the first direction. The second fixed terminal may include a second external connecting portion protruding from the side wall in the first direction. In this case, in the electromagnetic relay in which an arc generated between the first fixed contact and the first movable contact is extended in the direction away from the first external connecting portion, the possibility of re-ignition of the arc generated between the first fixed contact and the first movable contact can be reduced.
The first magnet may include a magnet end in the second direction. The magnet end of the first magnet may be disposed in the second direction with respect to the first fixed contact. In this case, the arc is easily drawn to the magnet end of the first magnet, and thereby the arc can be quickly cut off in the arc extension space.
The first magnet may include a first surface in a third direction from the first fixed contact toward the second fixed contact and a second surface opposite the first surface. The tapered portion may protrude in the third direction from the first surface of the first magnet when viewed from the moving directions of the movable contact piece. In this case, the bright spot of the arc that has moved to the first end moves to the back side of the first magnet more easily.
The first magnet may include a first surface extending in a third direction from the first fixed contact toward the second fixed contact and a second surface opposite the first surface. The first end of the first fixed terminal may include a corner portion that is disposed near the second surface of the first magnet when viewed from the moving directions of the movable contact piece and that is connected to the tapered portion. In this case, the movement of the bright spot of the arc on the first fixed terminal can be stopped at the corner portion. Thus, the arc is limited from being too far from the movable contact piece. As a result, the phenomenon of re-ignition of the arc due to its interruption is less likely to occur.
The first end of the first fixed terminal may include a first flat portion and a second flat portion apart from the first flat portion. The tapered portion may be disposed between the first flat portion and the second flat portion. In this case, for example, when the first fixed terminal is fixedly press-fitted into the case in the second direction, the press-fitting of the first fixed terminal to the case is facilitated.
The drive device may include a spool and a fixed iron core disposed inside the spool and in the second direction with respect to the first fixed terminal. The spool may include a collar portion configured to provide an insulating distance between the first fixed terminal and the fixed iron core. The collar portion of the spool may be disposed in a third direction extending from the first fixed contact toward the second fixed contact with respect to the first magnet. In this case, the arc is retained from hitting the collar portion, enhancing the durability of the collar portion. Further, extension of the arc is less likely to be hindered by the collar portion, and thereby the arc can be quickly cut off in the arc extension space.
The electromagnetic relay may further include a second magnet disposed opposite the first magnet and laterally to the first fixed contact. The second magnet may be configured to extend an arc generated between the second fixed contact and the second movable contact. The collar portion of the spool may be positioned between the first magnet and the second magnet when viewed from the moving directions of the movable contact piece. In this case, the arc can be quickly cut off in the arc extension space while securing the distance for insulation between the first fixed terminal and the fixed iron core and between the second fixed terminal and the fixed iron core.
Hereinafter, an electromagnetic relay 1 according to an embodiment will be described with reference to the drawings. As shown in
In the following description, the direction in which the contact device 3 and the drive device 4 are disposed with respect to a later-described base 21 of the case 2 is referred to as up (an example of a second direction), and the opposite direction is referred to as down (an example of a first direction). The direction in which the contact device 3 is disposed with respect to the drive device 4 is referred to as front, and the opposite is referred to as back. The left-right direction of the paper of
The case 2 has a box shape. The case 2 is made of an insulating material such as resin. The case 2 includes a base 21 and a cover 22. The base 21 supports the contact device 3 and the drive device 4. The base 21 includes a bottom 21a, outer walls 21b to 21e, and an inner wall 21f (see
The cover 22 is open downward and is attached to the outer walls 21b to 21e of the base 21 so as to cover the bottom 21a of the base 21 from above. The contact device 3 and the drive device 4 are accommodated in the case 2.
As shown in
The fixed terminals 11 and 12 are made of a conductive material such as copper. The fixed terminals 11 and 12 are plate-shaped terminals and extend in a direction orthogonal to the front-back direction. The fixed terminals 11 and 12 are supported by the bottom 21a of the base 21. The fixed terminals 11 and 12 are assembled to the base 21 from above. In the present embodiment, the fixed terminals 11 and 12 are fixedly press-fitted to the bottom 21a of the base 21. The fixed terminals 11 and 12 are disposed in front of the inner wall 21f.
As shown in
The first end 11c is the top end of the first fixed terminal 11. The first end 11c is exposed in the case 2. In the present embodiment, the first end 11c is entirely exposed in the case 2. The first end 11c extends in the left-right direction.
As shown in
The second fixed terminal 12 is apart from the first fixed terminal 11 to the right. The second fixed terminal 12 has a symmetrical shape with respect to the first fixed terminal 11. The second fixed terminal 12 includes a second fixed contact 12a, a second external connecting portion 12b, and a second end 12c. The second fixed contact 12a is disposed on the front surface of the second fixed terminal 12. The second fixed contact 12a is fixedly caulked to the second fixed terminal 12. Note that the second fixed contact 12a may be integrated with the second fixed terminal 12. The second external connecting portion 12b protrudes downward from the bottom 21a of the base 21 and is electrically connected to an external device (not shown). The second end 12c has a symmetrical shape with respect to the first end 11c of the first fixed terminal 11, and has a similar configuration to that of the first end 11c of the first fixed terminal 11. Thus, detailed description of the second end 12c will be omitted.
The movable contact piece 13 is a plate-shaped terminal and is made of a conductive material such as copper. The movable contact piece 13 is disposed in front of the fixed terminals 11 and 12. The movable contact piece 13 has a substantially T-shape when viewed from the front-back direction. The movable contact piece 13 includes a first movable contact 13a, a second movable contact 13b, an up-down extending portion 13c, and a left-right extending portion 13d.
The first movable contact 13a and the second movable contact 13b are fixedly caulked to the movable contact piece 13. The first movable contact 13a and the second movable contact 13b are disposed on the back surface of the left-right extending portion 13d. The first movable contact 13a faces the first fixed contact 11a in the front-back direction. The first movable contact 13a is able to be in contact with the first fixed contact 11a. The second movable contact 13b is apart from the first movable contact 13a to the right. The second movable contact 13b faces the second fixed contact 12a in the front-back direction. The second movable contact 13b is able to be in contact with the second fixed contact 12a. The first movable contact 13a and the second movable contact 13b may be integrated with the movable contact piece 13.
The up-down extending portion 13c extends in the up-down direction and connected to, at the upper part, the drive device 4. The left-right extending portion 13d extends in the left-right direction from the lower part of the up-down extending portion 13c.
The drive device 4 is disposed above the contact device 3. The drive device 4 moves the movable contact piece 13 in the direction in which the first movable contact 13a approaches the first fixed contact 11a and in the direction in which the first movable contact 13a separates from the first fixed contact 11a. Further, the drive device 4 moves the movable contact piece 13 in the direction in which the second movable contact 13b approaches the second fixed contact 12a and in the direction in which the second movable contact 13b separates from the second fixed contact 12a. In the present embodiment, the drive device 4 moves the movable contact piece 13 in the front-back direction (one example of the moving directions).
As shown in
The spool 41 is disposed above the fixed terminals 11 and 12. The spool 41 includes flange portions 41a and 41b, a body portion 41c, and a collar portion 41d. The flange portions 41a and 41b have an outer diameter larger than the outer diameter of the body portion 41c. The flange portion 41a is connected to the front end of the body portion 41c. The flange portion 41b is connected to the back end of the body portion 41c. The body portion 41c is tubular, and has a coil 42 wound around the outer circumference thereof. The collar portion 41d secures a distance for insulation between the fixed terminals 11 and 12 and the fixed iron core 47. As shown in
The coil 42 is wound around the outer circumference of the spool 41. The yoke 43 has an L-shaped bent shape. The yoke 43 includes a coupling portion 43a and an extending portion 43b. The coupling portion 43a is disposed behind the spool 41 and is coupled to the fixed iron core 47. The extending portion 43b extends forward from the upper end of the coupling portion 43a so as to cover the upper part of the coil 42.
The movable iron piece 44 is disposed in front of the fixed iron core 47. The movable iron piece 44 is rotatably supported by the yoke 43 at the front end of the extending portion 43b. The resin member 45 insulates the movable iron piece 44 and the movable contact piece 13. The resin member 45 couples the movable iron piece 44 and the movable contact piece 13. Specifically, the movable iron piece 44 and the movable contact piece 13 are made by insert-molding into the resin member 45. Thus, the resin member 45 and the movable contact piece 13 are rotatable integrally with the movable iron piece 44 in response to the rotation of the movable iron piece 44.
The return spring 46 is a coil spring and extends in the front-back direction. The return spring 46 has a front end connected to the movable iron piece 44 and a back end connected to a yoke 43. The return spring 46 forces the movable contact piece 13 forward via the movable iron piece 44 and the resin member 45. That is, the return spring 46 forces the movable contact piece 13 in the direction in which the first movable contact 13a separates from the first fixed contact 11a and in the direction in which the second movable contact 13b separates from the second fixed contact 12a. The fixed iron core 47 is disposed in the body portion 41c of the spool 41 and penetrates the flange portions 41a and 41b of the spool 41 in the front-back direction.
Next, the operation of the electromagnetic relay 1 will be described. While no voltage is applied to the coil 42, as shown in
Here, as shown in
The side wall 23 is configured by the bottom 21a of the base 21 in the present embodiment. The side wall 23 covers the accommodation space 24 and the gas inflow spaces 27 and 28 from below. The side wall 23 has through holes 23a and 23b. The through holes 23a and 23b penetrate the side wall 23 in the up-down direction. The through hole 23a is disposed below the magnet housing 25. The through hole 23b is disposed below the magnet housing 26.
The accommodation space 24 is disposed between the base 21 and the cover 22. The accommodation space 24 is between the magnet housing 25 and the magnet housing 26 in the left-right direction. The first fixed contact 11a, the second fixed contact 12a, and the movable contact piece 13 are accommodated in the accommodation space 24.
The magnet housing 25 is integrally formed with the base 21. The magnet housing 25 extends in the up-down direction and backward from the outer wall 21b of the base 21. The magnet housing 25 is disposed upwardly apart from the bottom 21a of the base 21. The magnet housing 25 is disposed to the left of the first fixed contact 11a and the first movable contact 13a. The magnet housing 25 is disposed between the accommodation space 24 and the gas inflow space 27. The magnet housing 25 partitions the accommodation space 24 and the gas inflow space 27 in the left-right direction. The magnet housing 25 extends above the first fixed contact 11a and the first movable contact 13a with respect to the bottom 21a of the base 21. The magnet housing 25 extends above the first fixed terminal 11 with respect to the bottom 21a of the base 21.
The magnet housing 25 has an inlet 25a. The inlet 25a is disposed at the lower end of the magnet housing 25 and opens downward. The inlet 25a is disposed above the bottom 21a of the base 21. The inlet 25a overlaps with the through hole 23a when viewed from the up-down direction.
The magnet housing 26 has a symmetrical shape with the magnet housing 25, and detailed description thereof will be omitted. The magnet housing 26 is disposed to the right of the second fixed contact 12a and the second movable contact 13b. The magnet housing 26 is disposed between the accommodation space 24 and the gas inflow space 28. The magnet housing 26 partitions the accommodation space 24 and the gas inflow space 28 in the left-right direction. The magnet housing 25 has an inlet 26a.
The gas inflow spaces 27 and 28 are disposed between the base 21 and the cover 22. The gas inflow spaces 27 and 28 are separate from the accommodation space 24. The gas inflow space 27 is disposed to the left of the accommodation space 24. The gas inflow space 27 is disposed between the magnet housing 25 and the outer wall 21d of the base 21 in the left-right direction. The gas inflow space 28 is disposed to the right of the accommodation space 24. The gas inflow space 28 is disposed between the magnet housing 26 and the outer wall 21e of the base 21 in the left-right direction.
The arc extension spaces 29, 30 are in communication with the accommodation space 24. The arc extension space 29 is expanded upward from the tapered portion 11e of the first end 11c of the first fixed terminal 11. The arc extension space 30 expands upward from the tapered portion of the second end 12c of the second fixed terminal 12.
The electromagnetic relay 1 includes support members 50 and 51, gas flow paths 60 and 61, a first magnet 70, and a second magnet 71.
The support member 50 is a separate body from the base 21. The support member 50 is, for example, fixedly press-fitted to the bottom 21a of the base 21. The support member 50 closes the inlet 25a of the magnet housing 25 and the through hole 23a of the side wall 23. The support member 50 supports the first magnet 70 from below. The support member 50 has a through hole 50a penetrating it in the left-right direction.
The support member 51 closes the inlet 26a of the magnet housing 26 and the through hole 23b of the side wall 23. The support member 51 has a through hole 51a. The support member 51 has a similar configuration to that of the support member 50, and detailed description thereof will be omitted.
The gas flow path 60 is disposed between the side wall 23 of the case 2 and the first magnet 70. The gas flow path 60 extends in the left-right direction and communicates the accommodation space 24 with the gas inflow space 27. The gas flow path 60 is disposed below the first magnet 70. The gas flow path 60 is configured by a through hole 60a and the through hole 50a of the support member 50. The through hole 60a penetrates between the magnet housing 25 and the side wall 23 in the left-right direction. The through hole 60a is formed to be continuous to the through hole 50a of the support member 50 in the left-right direction.
The gas flow path 61 is disposed between the side wall 23 of the case 2 and the second magnet 71. The gas flow path 61 extends in the left-right direction and communicates the accommodation space 24 with the gas inflow space 28. The gas flow path 61 is disposed below the second magnet 71. The gas flow path 61 is configured by a through hole 61a and the through hole 51a of the support member 51.
The through hole 61a penetrates between the magnet housing 26 and the side wall 23 in the left-right direction. The through hole 61a is formed to be continuous to the through hole 51a of the support member 51 in the left-right direction.
The first magnet 70 is, for example, a rectangular permanent magnet. The first magnet 70 is disposed to the left of the first fixed contact 11a and the first movable contact 13a. The first magnet 70 is housed in a magnet housing 25. The first magnet 70 is inserted into the magnet housing 25 from below. In the present embodiment, the first magnet 70 is configured by a magnet body and a yoke disposed to the left of the magnet body.
As shown in
The first magnet 70 includes a first surface 70b and a second surface 70c opposite the first surface 70b. The first surface 70b is a surface of the first magnet 70 in the direction from the first fixed contact 11a toward the second fixed contact 12a.
The first magnet 70 is disposed so that the magnetic flux in the vicinity of the first fixed contact 11a flows to the left. The first magnet 70 extends upward an arc A1 generated between the first fixed contact 11a and the first movable contact 13a. Specifically, for example, when a current flows from the first movable contact 13a toward the first fixed contact 11a, an upward Lorentz force acts on the arc A1, and the arc A1 is extended upward. As shown in
The second magnet 71 is disposed to the right of the second fixed contact 12a and the second movable contact 13b. The second magnet 71 is housed in the magnet housing 26. The second magnet 71 overlaps with the second fixed terminal 12 when viewed from the front-back direction.
The second magnet 71 is disposed so that the magnetic flux in the vicinity of the second fixed contact 12a flows to the left. The second magnet 71 is disposed to face the first magnet 70 at the different poles each other. The second magnet 71 extends downward an arc A2 generated between the second fixed contact 12a and the second movable contact 13b. Specifically, for example, when a current flows from the second fixed contact 12a toward the second movable contact 13b, a downward Lorentz force acts on the arc A2, and the arc A2 is extended downward. As shown in
As shown in
As shown in
As shown in
In the electromagnetic relay 1 described above, the arc A1 generated between the first fixed contact 11a and the first movable contact 13a is extended upward. That is, the bright spot of arc A1 moving on the first fixed terminal 11 moves to the first end 11c. The bright spot of the arc A1 that has moved to the first end 11c is guided by the tapered portion 11e of the first end 11c, and easily moves to the back side of the first magnet 70 and moves downward. Thus, the arc A1 can be significantly extended in the arc extension space 29, which expands upward from the tapered portion 11e, so that the arc A1 can be quickly cut off. As a result, the possibility of re-ignition of the arc A1 can be reduced.
The collar portion 41d of the spool 41 is disposed between the first magnet 70 and the second magnet 71 when viewed from the front-back direction. Thus, for example, compared with the case where the collar portion 41d extends to a position overlapping with the first magnet 70, the arc A1 is more limited from hitting the collar portion 41d. As a result, the collar portion 41d is less likely to be affected by the arc, enhancing the durability of the collar portion 41d. In addition, since the extension of the arc A1 is less likely to be hindered by the collar portion 41d, the arc A1 can be quickly cut off in the arc extension space 29.
In the present embodiment, the hot gas due to the arc A2 can be released from the accommodation space 24 to the gas inflow space 28 through the gas flow path 61, reducing the possibility of re-ignition of the arc A2.
The first end 11c of the first fixed terminal 11 includes the first flat portion 11d and the second flat portion 11g, and thereby the first fixed terminal 11 can be easily press-fitted to the base 21 from above. Further, since the first end 11c includes the corner portion 11h, the movement of the bright spot of the arc A1 on the first fixed terminal 11 can be stopped at the corner portion 11h. Thus, the arc A1 is limited from being too far from the movable contact piece 13. As a result, the phenomenon of re-ignition of the arc A1 due to its interruption is less likely to occur.
One embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the invention.
The configurations of the contact device 3 and the drive device 4 may be modified. For example, the configuration of first fixed terminal 11 may be changed. The first external connecting portion 11b may protrude from the outer wall 21d of the base 21. The first end 11c may include at least the tapered portion 11e. The entire tapered portion 11e may overlap with the first magnet 70 when viewed from the front-back direction. The tapered portion 11e may extend to the outer wall 21d. The position of the corner portion 11h may be changed. The drive device 4 may have a plunger type structure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-101220 | Jun 2021 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4421959 | Chen | Dec 1983 | A |
| 5546061 | Okabayashi | Aug 1996 | A |
| 6975194 | Nishida | Dec 2005 | B2 |
| 8519811 | Sugisawa | Aug 2013 | B2 |
| 20180182584 | Iwamoto | Jun 2018 | A1 |
| 20190035585 | Minowa | Jan 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 2016-24864 | Feb 2016 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20220406547 A1 | Dec 2022 | US |
