Patent Application
20230005691
The present invention relates to an electromagnetic relay.
An electromagnetic relay includes a contact case in which a fixed contact, a movable contact, and a movable contact piece are housed (see Japanese Patent No. 5163318). The contact case may expand and deform when the internal pressure inside the contact case rises. Accordingly, in Japanese Patent No. 5163318, the contact case is made of ceramic to ensure the strength of the contact case.
For example, in order to reduce the manufacturing cost of the contact case, the contact case can be made of resin. However, in the contact case made of resin, it is difficult to secure a strength of the contact case, and when the internal pressure in the contact case rises, the contact case may expand and deform.
An object of the present invention is, in an electromagnetic relay including a contact case made of resin, to improve a strength of the contact case.
An electromagnetic relay according to an aspect of the present invention includes a fixed terminal, a movable contact piece, a drive device, a contact case, at least one magnet, and at least one yoke. The fixed terminal includes a fixed contact. The movable contact piece includes a movable contact disposed to face the fixed contact. The drive device moves the movable contact piece in a direction in which the movable contact comes into contact with the fixed contact and in a direction in which the movable contact is separated from the fixed contact. The contact case is made of resin. The contact houses the fixed contact and the movable contact piece. The at least one magnet is disposed around the contact case for generating a magnetic field inside the contact case. The at least one yoke is fixed to the contact case.
In the electromagnetic relay, the strength of the contact case can be improved by the at least one yoke fixed to the contact case. As a result, when the internal pressure inside the contact case rises, deformation due to expansion of the contact case can be limited.
The at least one yoke may be disposed at least partially in contact with an outer surface of the contact case. In this case, deformation due to the expansion of the contact case can be effectively limited by the at least one yoke.
The at least one yoke may be fixedly press-fitted to the contact case. In this case, the at least one yoke can be rigidly fixed to the contact case.
The at least one yoke may include at least one press-fitting protrusion that protrude in a moving direction of the movable contact piece. The contact case may include at least one press-fitting hole to which the at least one press-fitting protrusion is press-fitted. The at least one press-fitting hole may be provided corresponding to the at least one press-fitting protrusion. In this case, the at least one yoke can be fixed to the contact case with a simple configuration.
The at least one yoke may be disposed so as to surround the contact case. In this case, deformation due to expansion of the contact case can be limited over a wide range of the contact case.
The at least one yoke may each include a middle portion extending in one of a longitudinal direction or a lateral direction of the movable contact piece, and a pair of side portions extending from both ends of the middle portion in the other of the longitudinal direction or the lateral direction of the movable contact piece. The at least one press-fitting protrusion may be provided on at least each of the pair of side portions among the middle portion and the pair of side portions. In this case, the at least one yoke can be rigidly fixed to the contact case at the at least one yoke having the pair of side portions.
The at least one yoke may be made by insert-molding into the contact case. In this case also, the strength of the contact case can be improved by the at least one yoke, and deformation due to expansion of the contact case can be limited.
The fixed terminal may be columnar and extend in the moving direction of the movable contact piece. In this case, in the electromagnetic relay including the columnar fixed terminal, deformation due to expansion of the contact case can be limited.
Hereinafter, an embodiment of an electromagnetic relay according to one aspect of the present invention will be described with reference to the drawings.
When referring to the drawings, the upper side in
The housing 2 has a substantially quadrangular box shape and is made of an insulating material such as resin. The housing 2 accommodates the contact device 3, the contact case 4, the drive device 5, the at least one magnet 6, and the at least one yoke 7.
As shown in
The fixed terminal 11 includes a fixed contact 11a and an external connecting portion 11b. The fixed contact 11a is disposed in the contact case 4. The external connecting portion 11b protrudes upward from the housing 2 to be exposed to the outside.
The fixed terminal 12 includes a fixed contact 12a and an external connecting portion 12b. The fixed contact 12a is disposed in the contact case 4. The external connecting portion 12b protrudes upward from the housing 2 to be exposed to the outside.
The movable contact piece 13 is a plate-shaped member that is long in one direction. Here, the movable contact piece 13 extends in the left-right direction. The movable contact piece 13 is disposed in the contact case 4. In the present embodiment, a longitudinal direction of the movable contact piece 13 coincides with the left-right direction. In addition, a lateral direction of the movable contact piece 13 coincides with the front-back direction.
The movable contact piece 13 includes movable contacts 13a and 13b. The movable contact 13a is disposed to face the fixed contact 11a to be able to be in contact with the fixed contact 11a. The movable contact 13b is disposed to face the fixed contact 12a o be able to be in contact with the fixed contact 12a. The movable contact 13b is disposed at a distance from the movable contact 13a in the left-right direction.
The movable contact piece 13 is disposed so as to be movable in a contact direction in which the movable contact 13a and 13b come into contact with the fixed contacts 11a and 12a and in a separating direction in which the movable contact 13a and 13b are separated from the fixed contacts 11a and 12a. That is, in the present embodiment, the movable contact piece 13 is movable in the up-down direction.
The movable mechanism 14 supports the movable contact piece 13. The movable mechanism 14 is disposed to be movable to a closed position where the fixed contacts 11a, 12a and the movable contacts 13a, 13b are in contact with each other, and to an open position where the fixed contacts 11a, 12a and the movable contacts 13a, 13b are separated from each other.
The movable mechanism 14 includes a drive shaft 21, a first holding member 22, a second holding member 23, and a contact spring 24. The drive shaft 21 is coupled to the movable contact piece 13. The drive shaft 21 extends in the up-down direction to penetrate the movable contact piece 13 in the up-down direction. The drive shaft 21 is disposed to be movable in the up-down direction.
The first holding member 22 is fixed to the drive shaft 21 at a position above the movable contact piece 13. The second holding member 23 is fixed to the drive shaft 21 at a position below the movable contact piece 13. The contact spring 24 is disposed between the movable contact piece 13 and the second holding member 23. The contact spring 24 forces the movable contact piece 13 in the contact direction via the second holding member 23.
The drive device 5 includes a movable iron core 31, a fixed iron core 32, a yoke 33, and a return spring 34. The drive device 5 further includes a coil and a spool (not shown). The drive device 5 moves the movable contact piece 13 in the contact direction and the separating direction via the movable mechanism 14 by an electromagnetic force. Note that the drive device 5 has a similar configuration as that of the conventional one, and detailed description thereof will be omitted.
The contact case 4 is made of resin. The contact case 4 accommodates the fixed contacts 11a, 12a and the movable contact piece 13. The contact case 4 includes a case portion 41 and a bottom portion 42. The case portion 41 is disposed on the top of the bottom portion 42.
The bottom portion 42 is disposed so as to cover the case portion 41 from below. The bottom portion 42 has a substantially rectangular shape when viewed from above, and extends in the front-back direction and the left-right direction from the case portion 41. The bottom portion 42 has a plurality of press-fitting holes 42a. The press-fitting holes 42a are disposed to correspond to press-fitting protrusions 71d and 72d, which will be described later. The press-fitting holes 42a are formed to be recessed from the upper surface to the lower surface of the bottom portion 42 at the positions outside the case portion 41. In the present embodiment, two press-fitting holes 42a are formed at the positions outside of each of the first to fourth side walls 41b to 41e.
The at least one magnet 6 is permanent magnet, is disposed around the contact case 4, and generates a magnetic field in the contact case 4. As a result, a Lorentz force acts on an arc that is generated at the contact point, and the arc is extended.
The at least one magnet 6 includes a first magnet 6a and a second magnet 6b. The first magnet 6a and the second magnet 6b are disposed so as to face each other in the left-right direction. The first magnet 6a is in contact with the outer surface of the first side wall 41b. The second magnet 6b is in contact with the outer surface of the second side wall 41c.
The at least one yoke 7 is fixed to the contact case 4. The at least one yoke 7 is at least partially disposed in contact with an outer surface of the contact case 4. The at least one yoke 7 are disposed so as to surround the contact case 4. The at least one yoke 7 includes a first yoke 71 and a second yoke 72.
The first yoke 71 has a substantially U-shape when viewed from above. Specifically, as shown in
The middle portion 71a extends in the front-back direction and the up-down direction. The middle portion 71a extends linearly when viewed from above. The middle portion 71a is disposed so as to cover the outer surface of the third side wall 41d. In the present embodiment, the middle portion 71a is disposed in contact with the outer surface of the third side wall 41d.
The first side portion 71b extends from the left end of the middle portion 72a in the front-back direction so as to cover the outer surface of the first side wall 41b. The first side portion 71b extends to a position where it overlaps with the first magnet 6a in the left-right direction and covers a part of the outer surface of the first magnet 6a.
The second side portion 71c faces the first side portion 71b in the left-right direction. The second side portion 71c extends in the front-back direction from the right end of the middle portion 71a so as to cover the outer surface of the second side wall 41c. The second side portion 71c extends to a position where it overlaps with the second magnet 6b in the left-right direction and covers a part of the outer surface of the second magnet 6b.
The press-fitting protrusions 71d are fixedly press-fitted to the press-fitting holes 42a. The first yoke 71 is fixed to the contact case 4 by the press-fitting of the press-fitting protrusions 71d to the press-fitting holes 42a. As shown in
The second yoke 72 has the same shape as that of the first yoke 71, but is disposed at a place different from that of the first yoke 71. The second yoke 72 is disposed at a distance from the first yoke 71 in the front-back direction. The second yoke 72 includes a middle portion 72a, a first side portion 72b, a second side portion 72c, and a plurality of press-fitting protrusions 72d.
The middle portion 72a is disposed so as to cover the outer surface of the fourth side wall 41e. In the present embodiment, the middle portion 72a is in contact with the outer surface of the fourth side wall 41e. The first side portion 72b extends from the right end of the middle portion 72a in the front-back direction so as to cover the outer surface of the second side wall 41c. The first side portion 72b extends to a position where it overlaps the second magnet 6b in the left-right direction and covers a part of the outer surface of the second magnet 6b. The second side portion 72c extends from the left end of the middle portion 72a in the anteroposterior direction so as to cover the outer surface of the first side wall 41b. The second side portion 72c extends to a position where it overlaps the first magnet 6a in the left-right direction and covers a part of the outer surface of the first magnet 6a.
The press-fitting protrusions 72d are fixedly press-fitted to the press-fitting holes 42a. The second yoke 72 is fixed to the contact case 4 by the press-fitting of the press-fitting protrusions 72d to the press-fitting holes 42a.
In the electromagnetic relay 100 having the above configuration, the strength of the contact case 4 can be improved by the at least one yoke 7 fixed to the contact case 4. As a result, when the internal pressure inside the contact case 4 rises, deformation due to expansion of the contact case 4 can be limited. In the present embodiment in particular, the middle portion 71a of the first yoke 71 is disposed in contact with the outer surface of the third side wall 41d of the case portion 41, and the middle portion 72a of the second yoke 72 is disposed in contact with the fourth side wall 41e of the case portion 41. It is disposed in contact with the outer surface. As a result, when the internal pressure inside the contact case 4 rises, deformation due to expansion of the contact case 4 can be effectively limited. Further, the plurality of press-fitting protrusions 71d and 72d are press-fitted into the plurality of press-fitting holes 42a and the at least one yoke 7 is fixed to the contact case 4. As such, the at least one yoke 7 can be firmly fixed to the contact case 4, which further increases the strength of the contact case 4.
One embodiment of the electromagnetic relay according to one aspect 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 present invention. For example, the shapes or arrangements of the housing 2, the contact device 3, the contact case 4, the drive device 5, the at least one magnet 6 or the at least one yoke 7 may be changed.
In the above embodiment, the fixed terminals 11 and 12 are columnar, but the fixed terminals 11 and 12 may be plate-shaped terminals extending in the left-right direction or the front-back direction.
In the above embodiment, the contact case 4 has a substantially quadrangular box shape, but it may have any shapes other than the quadrangular box shape, such as a polygonal shape, a columnar shape, or a substantially elliptical column shape.
As shown in
In the above embodiment, the at least one yoke 7 includes two yokes, the first yoke 71 and the second yoke 72, but the at least one yoke 7 may be single, or three or more. For example, as shown in
In the above embodiment, the first yoke 71 is disposed in contact with an outer surface of the contact case 4, and the second yoke 72 is disposed in contact with an outer surface of the contact case 4, but the first yoke 71 and the second yoke 72 are not necessarily disposed in contact with the contact case 4. Further, in the above embodiment, the first yoke 71 has a substantially U-shape, but depending on the arrangement or shape of the at least one magnet 6, the first side portion 71b and the second side portion 71c may be omitted from the first yoke 71. Similarly, the first side portion 72b and the second side portion 72c may be omitted from the second yoke 72.
The means for fixing the at least one yoke 7 to the contact case 4 is not limited to the above embodiment. For example, as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-229088 | Dec 2019 | JP | national |
This application is the U.S. National Phase of International Application No. PCT/JP2020/042578, filed on Nov. 16, 2020. This application claims priority to Japanese Patent Application No. 2019-229088, filed Dec. 19, 2019. The contents of those applications are incorporated by reference herein in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/042578 | 11/16/2020 | WO |
