Patent Application
20220415599
This application claims priority to Japanese Patent Application No. 2021-106421, filed Jun. 28, 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 case, a first fixed terminal, a second fixed terminal, a movable contact piece, a first magnet, a gas flow path, and a partition member. The case includes an accommodation space and a side wall covering the accommodation space in a first direction. The accommodation space includes a first space and a second space. The first fixed terminal includes a first fixed contact disposed in the first space and a first external connecting portion. The second fixed terminal is disposed apart from the first fixed terminal. The second fixed terminal includes a second fixed contact disposed in the second space and a second external connecting portion protruding from the side wall in the first direction. The movable contact piece extends between the first space and the second space. 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 first magnet configured to extend a first arc generated between the first fixed contact and the first movable contact in the first direction. The gas flow path is disposed between the side wall and the movable contact piece. The gas flow path includes an inlet communicating with the first space and an outlet communicating with the second space. The partition member is disposed between the movable contact piece and the gas flow path, and is configured to partition the first space and the second space from the gas flow path.
In the electromagnetic relay, the gas flow path between the side wall and the movable contact piece allows the hot gas due to the first arc to escape from the first space to the second space, decreasing the hot gas due to the first arc that stays in the first space. Further, the outlet of the gas flow path communicates with the second space, and thereby the outlet is disposed at a position apart from the first fixed contact. Thus, the hot gas, which has flowed from the first space to the second space through the gas flow path, is unlikely to return to the first space. As a result, the possibility of re-ignition of the first arc can be reduced.
The electromagnetic relay may further include a second magnet configured to extend a second arc generated between the second fixed contact and the second movable contact in a second direction opposite to the first direction. In this case, since the second arc is extended in the direction away from the outlet, the possibility of re-ignition of the second arc is reduced.
The electromagnetic relay may further include a drive device disposed in the second direction with respect to the first space and the second space. The drive device may be configured to move 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. In this case, in the electromagnetic relay in which the drive unit is disposed in the second direction from the first space and the second space, the possibility of re-ignition of the first arc is reduced.
The second space may be in communication with a space where the drive unit is installed. In this case, the hot gas due to the second arc can escape to the space where the drive is disposed.
The first magnet may be further configured to extend the first arc in a direction approaching the first magnet as the first arc is extended in the first direction. The case may be disposed between the first magnet and the movable contact piece and may further include an arc contact surface where the first arc contacts. The inlet of the gas flow path may face the arc contact surface. In this case, the hot gas due to the first arc can be efficiently guided to the gas flow path.
The inlet of the gas flow path may include a tapered portion that expands toward the arc contact surface. In this case, the hot gas due to the first arc can be more efficiently guided to the gas flow path.
The partition member may include a tapered surface inclined toward the arc contact surface in a direction approaching the side wall. In this case, the hot gas due to the first arc can be more efficiently guided to the gas flow path.
The partition member may further include a convex portion protruding toward the movable contact piece in a second direction opposite to the first direction. The convex portion may be disposed farther apart from the arc contact surface than the tapered surface. In this case, the convex portion can limit the hot gas, which has flowed from the first space to the second space through the gas flow path, from returning to the vicinity of the first movable contact.
The partition member may be a separate body from the side wall of the case. In this case, the partition member can be made of a material having excellent arc extinguishing performance.
The electromagnetic relay may further include a flow path member. The flow path member may be a separate body from the side wall of the case. The flow path member may be disposed between the side wall and the partition member and may constitute the gas flow path. In this case, the flow path member can be made of a material having excellent arc extinguishing performance.
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 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. The bottom 21a extends in a direction orthogonal to the up-down direction. The outer wall 21b extends upward from the front edge of the bottom 21a. The outer wall 21c extends upward from the back edge of the bottom 21a. The outer wall 21d extends upward from the left edge of the bottom 21a. The outer wall 21e extends upward from the right edge of the bottom 21a. The inner wall 21f extends upward from the bottom 21a. The inner wall 21f extends in the left-right direction between the outer wall 21d and the outer wall 21e. The inner wall 21f is disposed between the contact device 3 and the drive device 4 in the front-back direction.
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. In the present embodiment, the fixed terminals 11 and 12 are fixedly press-fitted to the bottom 21a of the base 21.
As shown in
The second fixed terminal 12 is apart from the first fixed terminal 11 to the left. 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 and a second external connecting portion 12b. 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 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 disposed apart from the first movable contact 13a to the left. 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 is connected to the drive device 4. The left-right extending portion 13d extends from the lower part of the up-down extending portion 13c in the left-right direction.
The drive device 4 is disposed above the contact device 3. The drive device 4 is disposed above a later-described first space 24a and a later-described second space 24b. 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.
As shown in
The spool 41 is tubular and extends in the front-back direction. The coil 42 is wound around the outer circumference of the spool 41. The coil 42 is disposed above the fixed terminals 11, 12. 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 spool 41 and penetrates the spool 41 in the front-back direction. The fixed iron core 47 is disposed above the fixed terminals 11, 12.
Next, the operation of the electromagnetic relay 1 will be described. While no voltage is applied to the coil 42, as shown in
Here, the case 2 further includes a side wall 23, an accommodation space 24, and magnet housings 25, 26. 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 from below.
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 accommodation space 24 is between the outer wall 21b and the inner wall 21f in the front-back 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 accommodation space 24 includes a first space 24a and a second space 24b. The first space 24a is a space where the first fixed contact 11a and the first movable contact 13a are disposed. The second space 24b is a space where the second fixed contact 12a and the second movable contact 13b are disposed. The second space 24b is in communication with the first space 24a. The boundary B between the first space 24a and the second space 24b is, for example, the center of the movable contact piece 13 in the left-right direction. The first space 24a and the second space 24b are, at the upper part, in communication with a space 30 where the drive device 4 is disposed. The drive device 4 is disposed above the first space 24a and the second space 24b in the case 2. The movable contact piece 13 extends between the first space 24a and the second space 24b.
The magnet housing 25 is integrally formed with the base 21. The magnet housing 25 is a concave portion that opens downward, and is formed so as to protrude upward from the side wall 23. The magnet housing 25 is disposed to the right of the first fixed contact 11a and the first movable contact 13a. The magnet housing 25 includes an arc contact surface 25a. The arc contact surface 25a is disposed between a later-described magnet 50 and the movable contact piece 13 in the left-right direction. The arc contact surface 25a extends in a direction orthogonal to the left-right direction. The arc contact surface 25a contacts with an arc A1 (an example of the first arc) generated between the first fixed contact 11a and the first movable contact 13a.
The magnet housing 26 has a symmetrical shape with the magnet housing 25, and is disposed to the left of the second fixed contact 12a and the second movable contact 13b.
The electromagnetic relay 1 includes magnets 50 and 51, a gas flow path 60, and a partition member 70. The magnet 50 is an example of the first magnet. The magnet 51 is an example of a second magnet. The magnets 50 and 51 are, for example, rectangular permanent magnets. The magnet 50 is disposed to the right of the first fixed contact 11a and the first movable contact 13a. The magnet 50 is housed in the magnet housing 25. The magnet 50 is inserted into the magnet housing 25 from below, and a support member 54 configure to support the magnet 50 from below retains the magnet 50 within the magnet housing 25.
The magnet 50 is disposed so that the magnetic flux in the vicinity of the first fixed contact 11a flows to the right. As shown in
The magnet 51 is disposed to the left of the second fixed contact 12a and the second movable contact 13b. The magnet 51 is housed in the magnet housing 26. The magnet 51 is inserted into the magnet housing 26 from below, and a support member 55 configure to support the magnet 51 from below retains the magnet 51 within the magnet housing 26.
The magnet 51 is disposed so that the magnetic flux in the vicinity of the second fixed contact 12a flows to the right. The magnet 51 is disposed to face the magnet 50 at the different poles each other. The magnet 51 extends upward an arc A2 (an example of the second arc) 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, an upward Lorentz force acts on the arc A2, and the arc A2 is extended upward. As shown in
The gas flow path 60 is disposed in the accommodation space 24. The gas flow path 60 is a path for releasing the hot gas due to the first arc from the first space 24a to the second space 24b. The gas flow path 60 is disposed below the first space 24a to the second space 24b. The gas flow path 60 is disposed between the side wall 23 and the movable contact piece 13 in the up-down direction. The gas flow path 60 is disposed between the magnet housing 25 and the magnet housing 26 in the left-right direction. The gas flow path 60 extends in the left-right direction. The gas flow path 60 is configured by the side wall 23, the partition member 70, the outer wall 21b, and the inner wall 21f.
The gas flow path 60 includes an inlet 61 and an outlet 62. The inlet 61 is in communication with the first space 24a. The inlet 61 faces the arc contact surface 25a. The inlet 61 includes a tapered portion 61a that expands toward the arc contact surface 25a. The inlet 61 is closer to the arc contact surface 25a than the center of the first fixed contact 11a and the center of the first movable contact 13a in the left-right direction.
The outlet 62 is in communication with the second space 24b. The outlet 62 faces the magnet housing 26. The outlet 62 includes a tapered portion 62a that expands toward the magnet housing 26. The outlet 62 is closer to the magnet housing 26 than the center of the second fixed contact 12a and the center of the second movable contact 13b in the left-right direction.
The partition member 70 is a separate body from the base 21. The partition member 70 is made of, for example, a material having better arc extinguishing performance than that of the base 21. The partition member 70 may be made of the same material as that of the base 21. The partition member 70 is fixed to the base 21.
The partition member 70 is disposed in the accommodation space 24. The partition member 70 is disposed between the movable contact piece 13 and the gas flow path 60. The partition member 70 partitions the first space 24a and the second space 24b from the gas flow path 60. The partition member 70 extends in the left-right direction and the front-back direction. The partition member 70 has, in the front-back direction, side surfaces that are in contact with the outer wall 21b and the inner wall 21f. The side surfaces of the partition member 70 in the left-right direction are separated from the magnet housings 25 and 26. The lower surface of the partition member 70 is separated from the side wall 23.
The partition member 70 includes a concave portion 70a, convex portions 70b, 70c, and tapered surfaces 70d, 70e. The concave portion 70a is formed on the lower surface of the partition member 70. The concave portion 70a is formed at the center of the partition member 70 in the left-right direction. The concave portion 70a is open downward.
The partition member 70 is supported by support portions 21g and 21h that are formed on the base 21. Specifically, the concave portion 70a of the partition member 70 is supported by the support portions 21g and 21h. The support portion 21g has a shape protruding from the outer wall 21b toward the accommodation space 24. The support portion 21g is connected to the side wall 23. The support portion 21h has a shape protruding from the inner wall 21f toward the accommodation space 24. The support portion 21h is connected to the side wall 23. The support portion 21g is separated from the support portion 21g in the front-back direction.
The convex portions 70b and 70c are formed on the upper surface of the partition member 70. The convex portions 70b and 70c protrude upward toward the movable contact piece 13. The convex portions 70b and 70c are disposed farther from the arc contact surface 25a than the tapered surface 70d in the left-right direction. The convex portion 70b is disposed in the first space 24a. The convex portion 70b is disposed to the left of the first fixed contact 11a and the first movable contact 13a in the first space 24a. The convex portion 70c is disposed in the second space 24b. The convex portion 70c is disposed to the right of the second fixed contact 12a and the second movable contact 13b in the second space 24b.
The tapered surfaces 70d and 70e are formed on the upper surface of the partition member 70. The tapered surface 70d is disposed below the first fixed contact 11a and the first movable contact 13a. The tapered surface 70d is inclined toward the arc contact surface 25a in a direction approaching the side wall 23. The tapered surface 70e is disposed below the second fixed contact 12a and the second movable contact 13b. The tapered surface 70e is inclined toward the magnet housing 26 in a direction approaching the side wall 23.
In the electromagnetic relay 1 described above, the gas flow path 60 between the side wall 23 of the case 2 and the movable contact piece 13 allows the hot gas due to the arc A1 to escape from the first space 24a to the second space 24b. Accordingly, the hot gas due to the arc A1 is hindered from staying in the first space 24a. Specifically, as shown by the alternate long and short dash line in
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. The drive device 4 may have a plunger type structure. The configuration of the case 2 may be changed. The arrangement and shape of the magnets 50 and 51 may be changed.
The shape of the partition member 70 may be changed. The partition member 70 may have any shape that partitions the first space 24a and the second space 24b from the gas flow path 60. For example, at least one of the convex portions 70b and 70c may be omitted, or a convex portion may be formed at the boundary B between the first space 24a and the second space 24b.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-106421 | Jun 2021 | JP | national |
