Patent Application
20210202198
The present invention relates to an electromagnetic relay.
Conventionally, electromagnetic relays that open and close an electric circuit are known. For example, an electromagnetic relay described in Japanese Laid-Open Patent Publication No. 2014-017086 includes a contact device including a fixed contact and a movable contact piece, an electromagnetic drive device, and a drive shaft. The electromagnetic drive device includes a coil, a fixed iron core, and a movable iron core. The drive shaft is made from a conductive material such as metal and is coupled to the movable contact piece and the movable iron core so as to be integrally movable.
When a voltage is applied to the coil of the electromagnetic drive device, the movable iron core is attracted to the fixed iron core and moves upward together with the drive shaft. With the movement of the movable iron core and the drive shaft, the movable contact piece moves toward the fixed contact and contacts the fixed contact.
In a case where the drive shaft has conductivity, it is necessary to ensure insulation between the movable contact piece and the movable iron core that are coupled to the drive shaft. In order to ensure the insulation between the movable contact piece and the movable iron core, it is necessary to provide a component for ensuring the insulation or to ensure an insulation distance between the movable contact piece and the movable iron core by a part combined with another component. In this case, the number of components may increase and the degree of freedom of design may be limited.
An object of the present invention is to ensure insulation between a movable contact piece and a movable iron core while suppressing an increase in the number of components.
(1) An electromagnetic relay according to one aspect of the present invention includes a fixed contact, a movable contact piece, a drive shaft, and a movable iron core. The movable contact piece includes a movable contact disposed facing the fixed contact and is movable in a first direction in which the movable contact piece contacts the fixed contact and a second direction in which the movable contact piece separates from the fixed contact. The drive shaft extends in the first direction and the second direction and is coupled to the movable contact piece. The movable iron core is coupled to the drive shaft so as to be integrally movable on the first direction side or the second direction side with respect to the movable contact piece. The drive shaft includes a first contact portion contacting the movable contact piece, a second contact portion contacting the movable iron core, and an insulating portion made from an insulating material and insulating the movable contact piece and the movable iron core from each other.
In this electromagnetic relay, the insulation between the movable contact piece and the movable iron core can be ensured by the insulating portion of the drive shaft that is made from the insulating material. As a result, it is not necessary to provide a component for ensuring the insulation between the movable contact piece and the movable iron core or to ensure an insulation distance between the movable contact piece and the movable iron core by a part combined with another component. This enables to reduce the number of components and the assembly steps while increasing the degree of freedom of design.
(2) Preferably, at least one of the first contact portion or the second contact portion is covered with the insulating portion. In this case, it is also possible to reduce the number of components and the assembly steps while increasing the degree of freedom of design.
(3) Preferably, the drive shaft further includes a metal portion that extends in the first direction and the second direction and that is entirely covered with the insulating portion. In this case, rigidity of the drive shaft can be increased.
(4) Preferably, the drive shaft further includes a flange portion made from metal and the electromagnetic relay further includes a contact spring contacting the flange portion of the drive shaft. In this case, for example, as compared with a case where the flange portion is made from an insulating material such as a resin, it is possible to prevent resin waste from being generated due to contact between the flange portion and the contact spring.
(5) Preferably, the first contact portion and the second contact portion are made from metal and the insulating portion is disposed between the first contact portion and the second contact portion. In this case, it is also possible to reduce the number of components and the assembly steps while increasing the degree of freedom of design.
(6) Preferably, the electromagnetic relay further includes a contact case housing the movable contact piece. The contact case includes a through hole through which the drive shaft extends and a portion of the drive shaft that extends through the through hole is covered with the insulating portion.
Hereinafter, embodiments of an electromagnetic relay according to one aspect of the present invention will be described with reference to the drawings.
The housing 2 includes a case 2a and a cover 2b. The case 2a has a substantially rectangular box shape with an upper side open. The cover 2b covers the upper side of the case 2a. The case 2a and the cover 2b are made from an insulating material. The contact device 3, the drive shaft 4, and the electromagnetic drive device 5 are housed inside the housing 2.
A contact case 11 that houses the contact device 3 and a contact cover 12 that covers the upper side of the contact case 11 are disposed in the housing 2. The contact case 11 and the contact cover 12 are made from an insulating material.
The contact case 11 includes a bottom portion 11a, a cylindrical portion 11b, a first contact support portion 11c, and a second contact support portion 11d. The bottom portion 11a is formed in a rectangular plate shape. The longitudinal direction of the bottom portion 11a coincides with the left-right direction in
The cylindrical portion 11b cylindrically extends in the axial direction. The cylindrical portion 11b protrudes downward from a center of the bottom portion 11a and protrudes upward from the center of the bottom portion 11a. The cylindrical portion 11b has a through hole 18 that penetrates the bottom portion 11a in the axial direction. The through hole 18 penetrates the center of the bottom portion 11a in the axial direction. The drive shaft 4 penetrates the through hole 18 in the axial direction. The cylindrical portion 11b does not necessarily have a cylindrical shape.
The first contact support portion 11c is disposed leftward from the center of the bottom portion 11a in the longitudinal direction. The first contact support portion 11c is formed in a rectangular shape to protrude upward from the bottom portion 11a. The second contact support portion 11d is disposed rightward from the center of the bottom portion 11a in the longitudinal direction. The second contact support portion 11d is formed in a rectangular shape to protrude upward from the bottom portion 11a.
The contact cover 12 covers the upper side of the contact case 11. The contact cover 12 includes an arc extension wall 12a that extends toward the bottom portion 11a. The arc extension wall 12a is made from, for example, a resin or a ceramic material such as aluminum oxide.
The first fixed terminal 14 extends in the left-right direction and is supported by the first contact support portion 11c of the contact case 11 in the housing 2. The first fixed terminal 14 includes a first fixed contact 14a and a first external connection portion 14b. The first fixed contact 14a is disposed above the first contact support portion 11c in the contact case 11. The first fixed contact 14a is an example of a fixed contact. The first external connection portion 14b protrudes from the case 2a in the left-right direction.
The second fixed terminal 15 extends in the left-right direction and is supported by the second contact support portion 11d of the contact case 11 in the housing 2. The second fixed terminal 15 includes a second fixed contact 15a and a second external connection portion 15b. The second fixed contact 15a is disposed apart from the first fixed contact 14a in the left-right direction. The second fixed contact 15a is an example of a fixed contact.
The movable contact piece 16 extends in the left-right direction in the contact case 11. The movable contact piece 16 is disposed facing the first fixed contact 14a and the second fixed contact 15a. The movable contact piece 16 is disposed above the first fixed contact 14a and the second fixed contact 15a.
The movable contact piece 16 includes a first movable contact 16a, a second movable contact 16b, and a through hole 16c. The first movable contact 16a is disposed facing the first fixed contact 14a and configured to contact the first fixed contact 14a. The second movable contact 16b is disposed facing the second fixed contact 15a and configured to contact the second fixed contact 15a. The first movable contact 16a and the second movable contact 16b are examples of movable contacts. The through hole 16c is a hole that penetrates in the axial direction and is formed at a position that overlaps with the axis Ax of the drive shaft 4.
The movable contact piece 16 is movable in a contact direction Z1 in which the movable contact piece 16 contacts the first fixed contact 14a and the second fixed contact 15a and a separation direction Z2 in which the movable contact piece 16 separates from the first fixed contact 14a and the second fixed contact 15a. The contact direction Z1 is an example of a first direction and the separation direction Z2 is an example of a second direction.
The contact direction Z1 is a direction in which the first movable contact 16a and the second movable contact 16b contact the first fixed contact 14a and the second fixed contact 15a (downward in
As illustrated in
The drive shaft 4 extends in the contact direction Z1 and the separation direction Z2. A first end 4a side of the drive shaft 4 on the separation direction Z2 side is disposed in the contact case 11 and a second end 4b side of the drive shaft 4 on the contact direction Z1 side is disposed in a housing portion 33a of a spool 33 described later. The drive shaft 4 is coupled to the movable contact piece 16 via the contact piece holding unit 17 and is movable together with the movable contact piece 16 in the contact direction Z1 and the separation direction Z2.
The drive shaft 4 includes a metal portion 41 made from metal and an insulating portion 42 made from an insulating material. The drive shaft 4 is formed by integrally molding the insulating portion 42 with the metal portion 41 by insert molding. In the present embodiment, the metal portion 41 is entirely covered with the insulating portion 42. The metal portion 41 extends in the contact direction Z1 and the separation direction Z2. The metal portion 41 has a rod shape and extends from the first end 4a to the second end 4b.
The insulating portion 42 is made from an insulating material and insulates the movable contact piece 16 and the movable iron core 34 from each other. The insulating material is, for example, a thermoplastic resin such as a liquid crystal polymer (LCP) or a polybutylene terephthalate (PBT) resin, or a thermosetting resin.
The drive shaft 4 includes a head portion 4c, a flange portion 4d, and a shaft portion 4e. The head portion 4c is disposed at the first end 4a and penetrates the through hole 16c of the movable contact piece 16 in the separation direction Z2. The head portion 4c is configured to contact the through hole 16c of the movable contact piece 16. The head portion 4c is composed of the metal portion 41 and the insulating portion 42. The head portion 4c is an example of a first contact portion.
The flange portion 4d is disposed at the head portion 4c on the contact direction Z1 side. The outer diameter of the flange portion 4d is larger than the diameter of the through hole 16c of the movable contact piece 16. The surface of the flange portion 4d on the separation direction Z2 side is in contact with the movable contact piece 16. The surface of the flange portion 4d on the contact direction Z1 side is in contact with the contact spring 25. The flange portion 4d is composed of the insulating portion 42. The flange portion 4d is an example of the first contact portion.
The shaft portion 4e extends from the flange portion 4d toward the contact direction Z1. The shaft portion 4e passes through the through hole 18 of the contact case 11 and extends into the housing portion 33a of the spool 33. Therefore, a portion of the shaft portion 4e that passes through the through hole 18 is covered with the insulating portion 42. The shaft portion 4e includes the metal portion 41 and the insulating portion 42. The shaft portion 4e is an example of a second contact portion.
The electromagnetic drive device 5 moves the drive shaft 4 in the contact direction Z1 and the separation direction Z2. In the housing 2, the electromagnetic drive device 5 is disposed in a space different from where the contact device 3 is disposed. In this embodiment, the electromagnetic drive device 5 is disposed below the contact case 11.
The electromagnetic drive device 5 includes a coil 32, a spool 33, a movable iron core 34, a fixed iron core 35, an urging member 36, and a yoke 37.
The coil 32 is wound around the outer circumference of the spool 33. The spool 33 includes a housing portion 33a. The housing portion 33a is provided on the inner circumference of the spool 33. The housing portion 33a has a cylindrical shape and extends in the axial direction.
The movable iron core 34 is disposed in the housing portion 33a. The movable iron core 34 has a cylindrical shape and its center is penetrated by the drive shaft 4 in the axial direction. The movable iron core 34 is movable in the axial direction together with the drive shaft 4. In the present embodiment, the movable iron core 34 is coupled to the drive shaft 4 so as to be integrally movable on the contact direction Z1 side with respect to the movable contact piece 16. Specifically, as illustrated in
The fixed iron core 35 is disposed facing the movable iron core 34 on the contact direction Z1 side with respect to the movable iron core 34 in the housing portion 33a. The fixed iron core 35 is fixed to the yoke 37.
The urging member 36 is, for example, a coil spring, and is disposed between the movable iron core 34 and the fixed iron core 35. The urging member 36 urges the movable iron core 34 toward the separation direction Z2. Therefore, the urging member 36 is disposed between the movable iron core 34 and the fixed iron core 35 in a compressed state.
The yoke 37 includes a first yoke 37a and a second yoke 37b. The first yoke 37a has a plate shape and is disposed between the bottom portion 11a of the contact case 11 and the spool 33. The first yoke 37a overlaps with a lower portion of the cylindrical portion 11 b in the left-right direction. The first yoke 37a is connected to a ring iron core 38. The second yoke 37b has a substantially U shape and a bottom portion of the second yoke 37b is disposed below the spool 33. The upper ends of both sides of the second yoke 37b are connected to the first yoke 37a.
Next, the operation of the electromagnetic relay 100 will be described.
When the application of the voltage to the coil 32 is stopped, the movable iron core 34 moves in the separation direction Z2 due to the elastic force of the urging member 36, and the first movable contact 16a and the second movable contact 16b separate from the first fixed contact 14a and the second fixed contact 15a.
When the first movable contact 16a and the second movable contact 16b contact the first fixed contact 14a and the second fixed contact 15a, it is necessary to ensure insulation between the movable contact piece 16 and the movable iron core 34. In the present embodiment, the insulation between the movable contact piece 16 and the movable iron core 34 is ensured by the insulating portion 42 of the drive shaft 4. As a result, it is not necessary to provide a new component for ensuring the insulation or to ensure an insulation distance between the movable contact piece and the movable iron core by a part combined with another component. This enables to reduce the number of components and the assembly steps of the electromagnetic relay 100 while increasing the degree of freedom of design.
Although an embodiment of the electromagnetic relay according to one aspect of the present invention has been described so far, the present invention is not limited to the above embodiment and various modifications can be made without departing from the gist of the invention. For example, the configuration of the electromagnetic drive device 5 may be changed. The shape or disposition of the movable contact piece 16, the coil 32, the spool 33, the movable iron core 34, the fixed iron core 35, the urging member 36, or the yoke 37 may be changed. The shape or disposition of the housing 2, the contact case 11, or the contact cover 12 may be changed. For example, the present invention may be applied to a configuration in which the movable iron core 34 is disposed on the separation direction Z2 side with respect to the movable contact piece 16.
In the above embodiment, the metal portion 41 is disposed on the drive shaft 4 to increase the rigidity of the drive shaft 4, but the metal portion 41 is not necessarily disposed. For example, as illustrated in FIG.4, the entire drive shaft 4 may be formed of the insulating portion 42. That is, the drive shaft 4 may be formed of only an insulating material.
The shape of the metal portion 41 is not limited to that of the above embodiment. For example, as illustrated in
In the above embodiment, the insulating portion 42 covers the entire metal portion 41, but does not necessarily cover the entire metal portion 41. The insulating portion 42 only needs to be configured to insulate the movable contact piece 16 and the movable iron core 34 from each other.
For example, as illustrated in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-167629 | Sep 2018 | JP | national |
This application is the U.S. National Phase of International Application No. PCT/JP2019/008504, filed on Mar. 5, 2019. This application claims priority to Japanese Patent Application No. 2018-167629, filed Sep. 7, 2018. The contents of those applications are incorporated by reference herein in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/008504 | 3/5/2019 | WO | 00 |
