Patent Application
20210296070
The present invention relates to a relay.
Some relays are equipped with a magnet for extinguishing an arc that occurs at contact points. For example, in Japanese Patent Application Publication No. 2013-98051A, two magnets are arranged so as to mutually oppose each other in the width direction of a movable contact piece. The movable contact piece is arranged between the two magnets. When an arc is generated between the contact points, a Lorentz force acts on the arc due to the magnetic force of the magnets. Thereby, the arc is extinguished as a result of the arc being stretched into the space lateral to the movable contact piece.
On the other hand, in some relays, the behavior of an arc is affected by the self-magnetic field generated by an electric current flowing through the fixed terminal. For example,
However, in the relay shown in
Here, in order to suitably extinguish an arc, it is important to appropriately set the distance between the starting point of the arc and a wall portion arranged on the side of the movable contact piece. For example, when the distance between the starting point of the arc and the wall portion is small, the space for stretching the arc becomes narrow. For that reason, it becomes difficult to sufficiently stretch the arc. Further, when the distance between the starting point of the arc and the wall portion is large, the force for pressing the arc against the wall portion becomes weak. For that reason, it becomes difficult to sufficiently extinguish the arc. Accordingly, the arc can be suitably extinguished by appropriately setting the distance between the starting point of the arc and the wall portion in the direction in which the arc is stretched.
However, as described above, when the behavior of the arc is affected by the self-magnetic field arising from the electric current flowing through the fixed terminal, the magnitude of the Lorentz force F20 heading to the inner side in the longitudinal direction of the movable contact piece 100 changes in accordance with the magnitude of the electric current. Therefore, the direction in which the arc is stretched changes by a change in the direction of the resultant force F30 of the Lorentz forces.
For example, as shown in
Therefore, the direction in which the arc is stretched differs between when the electric current value is 100 A and when the electric current value is 3,000 A. Accordingly, as shown in
An object of the present invention is to appropriately secure the arc-extinguishing ability of a relay according to the magnitude of an electric current flowing through the contacts.
A relay according to one aspect includes a movable contact piece, a fixed contact, a drive device, a magnet for arc extinguishing, a fixed terminal, and a wall portion. The movable contact piece includes a movable contact. The fixed contact is arranged opposite the movable contact. The drive device moves the movable contact piece in a direction in which the movable contact makes contact with the fixed contact and in a direction in which the movable contact is separated therefrom. The magnet for arc extinguishing is arranged so as to apply a Lorentz force in a first extension direction to an arc generated between the movable contact and the fixed contact. The fixed terminal includes a contact support portion and an intermediate portion. The fixed contact is mounted in the contact support portion. The intermediate portion applies a Lorentz force to the arc in a second extension direction different from the first extension direction when an electric current flows through the intermediate portion. The wall portion is arranged separated from the movable contact piece in the first extension direction by an arc-extinguishing space.
The wall portion includes a first wall surface and a second wall surface. The first wall surface is arranged facing the arc-extinguishing space, and is arranged opposite the first extension direction with respect to the movable contact and the fixed contact. The second wall surface is arranged facing the arc-extinguishing space, and arranged in the second extension direction with respect to the first wall surface. The distance from the movable contact piece to the second wall surface differs from the distance from the movable contact piece to the first wall surface.
In the relay according to the present aspect, when the electric current flowing through the contacts is small, the arc is stretched toward the first wall surface. Also, when the electric current flowing through the contacts is large, the arc is stretched toward the second wall surface. The distance from the movable contact piece to the second wall surface is different from the distance from the movable contact piece to the first wall surface. Accordingly, the arc can be appropriately extinguished by appropriately setting the distance from the movable contact piece to the second wall surface and the distance from the movable contact piece to the first wall surface according to the difference in the magnitude of the electric current. Thereby, in the relay according to this aspect, it is possible to appropriately secure the arc-extinguishing ability according to the magnitude of the electric current flowing through the contacts.
The distance from the movable contact piece to the second wall surface may be larger than the distance from the movable contact piece to the first wall surface. In this case, when the electric current is large, a space sufficiently large for stretching the arc can be secured between the second wall surface and the movable contact piece.
The wall portion may include a connecting wall surface arranged between the first wall surface and the second wall surface. The distance from the movable contact piece to the connecting wall surface may be smaller than the distance from the movable contact piece to the second wall surface and may be larger than the distance from the movable contact piece to the first wall surface. In this case, when the arc is stretched between the first wall surface and the second wall surface, the arc can be appropriately extinguished.
The connecting wall surface may be inclined so that the distance from the movable contact piece increases toward the second extension direction. In this case, when the arc is stretched between the first wall surface and the second wall surface, the arc can be appropriately extinguished.
The distance from the movable contact piece to the second wall surface may be smaller than the distance from the movable contact piece to the first wall surface. In this case, when the electric current is large but the voltage is small, the stretched arc can be pressed against the second wall surface with sufficient force. Thereby, the arc can be appropriately extinguished.
The wall portion may include a connecting wall surface arranged between the first wall surface and the second wall surface. The distance from the movable contact piece to the connecting wall surface may be larger than the distance from the movable contact piece to the second wall surface and smaller than the distance from the movable contact piece to the first wall surface. In this case, when the arc is stretched between the first wall surface and the second wall surface, the arc can be appropriately extinguished.
The connecting wall surface may be inclined so that the distance from the movable contact piece decreases toward the second extension direction. In this case, when the arc is stretched between the first wall surface and the second wall surface, the arc can be appropriately extinguished.
The first movable contact and the second movable contact may be arranged apart from each other in the longitudinal direction of the movable contact piece. The magnet may be arranged so as to generate a magnetic flux between the movable contact and the fixed contact in a direction heading to the outer side of the movable contact piece in the longitudinal direction. The intermediate portion may be arranged on the outer side of the fixed contact in the longitudinal direction and may extend in the moving direction of the movable contact piece. In this case, the resultant force of the Lorentz force in the width direction of the movable contact piece intersecting in the longitudinal direction of the movable contact piece and the Lorentz force in the direction heading to the inner side of the movable contact piece in the longitudinal direction acts on the arc. Then, as the electric current increases, the direction in which the arc is stretched changes heading to the inner side of the movable contact piece in the longitudinal direction.
The first extension direction may be the width direction of the movable contact piece intersecting the longitudinal direction of the movable contact piece. The second extension direction may be a direction heading to the inner side of the movable contact piece in the longitudinal direction. In this case, the resultant force of the Lorentz force in the width direction of the movable contact piece intersecting the longitudinal direction of the movable contact piece and the Lorentz force in the direction heading to the inner side of the movable contact piece in the longitudinal direction acts on the arc. Then, as the electric current increases, the direction in which the arc is stretched changes heading to the inner side of the movable contact piece in the longitudinal direction.
The relay may further include a contact case for housing the movable contact piece and the fixed contact. The wall portion may be separate from the contact case. In this case, the formation of the wall portion becomes easy.
The wall portion may be formed of an arc-extinguishing material that generates an arc-extinguishing gas by the heat of the arc. In this case, the arc can be extinguished more appropriately.
Hereinbelow, a relay according to the embodiment will be described with reference to the drawings.
The case 2 houses the contact device 3 and the drive device 4. The case 2 is made of an insulating resin. The case 2 includes a case body 2a and a lid 2b. The contact device 3 and the drive device 4 are arranged in the case body 2a. The lid 2b is separate from the case body 2a. The lid 2b is attached to the case body 2a.
The case body 2a includes a contact case 18, an outer case 19, and an inner case 20. In the contact case 18, the inside of the case 2 is divided into a first storage portion S1 and a second storage portion S2. The contact device 3 is arranged in the first storage portion S1. The drive device 4 is arranged in the second storage portion S2. The outer case 19 houses the contact case 18 inside. The inner case 20 is attached to the contact case 18. The inner case 20 will be described in detail later.
The contact device 3 includes a first fixed terminal 5, a second fixed terminal 6, a movable contact piece 7, and a contact piece holder 8. The first fixed terminal 5, the second fixed terminal 6, and the movable contact piece 7 are formed of a conductive material such as copper. The first fixed terminal 5 includes a first fixed contact 11. The second fixed terminal 6 includes a second fixed contact 12. The first fixed contact 11 and the second fixed contact 12 are arranged apart from each other in the left-right direction.
The movable contact piece 7 extends in the left-right direction. In the present embodiment, the longitudinal direction of the movable contact piece 7 coincides with the left-right direction. The movable contact piece 7 includes a first movable contact 13 and a second movable contact 14. The first movable contact 13 and the second movable contact 14 are arranged apart from each other in the left-right direction. The first movable contact 13 is arranged opposite the first fixed contact 11. The second movable contact 14 is arranged opposite the second fixed contact 12.
The movable contact piece 7 includes a first end portion 7a and a second end portion 7b. The first end portion 7a is one end portion of the movable contact piece 7 in the left-right direction. The second end portion 7b is the other end portion of the movable contact piece 7 in the left-right direction. In the present embodiment, the first end portion 7a is the left end portion of the movable contact piece 7. The second end portion 7b is the right end portion of the movable contact piece 7. The first movable contact 13 is arranged between the center of the movable contact piece 7 in the left-right direction and the first end portion 7a. The second movable contact 14 is arranged between the center of the movable contact piece 7 in the left-right direction and the second end portion 7b.
The movable contact piece 7 is arranged so as to be movable in the up-down direction. Specifically, the movable contact piece 7 is arranged to be movable in a contact direction Z1 and a separating direction Z2. The contact direction Z1 is the direction in which the first movable contact 13 and the second movable contact 14 come into contact with the first fixed contact 11 and the second fixed contact 12 (downward in
The contact piece holder 8 holds the movable contact piece 7. The contact piece holder 8 holds the movable contact piece 7 at the center of the movable contact piece 7 in the left-right direction. The contact piece holder 8 includes a drive shaft 15, a holder 16, and a contact spring 17. The drive shaft 15 extends in the up-down direction.
The drive shaft 15 connects the movable contact piece 7 and the drive device 4. The drive shaft 15 is movably arranged in the contact direction Z1 and the separating direction Z2. The holder 16 is connected to the movable contact piece 7 and holds the movable contact piece 7. The contact spring 17 is arranged between the drive shaft 15 and the holder 16. The drive shaft 15 is connected to the holder 16 via the contact spring 17.
The first fixed terminal 5 includes a first contact support portion 21, a first intermediate portion 22, and a first external connection portion 24. The first fixed contact 11 is provided in the first contact support portion 21. The first contact support portion 21 extends from the first fixed contact 11 to the outer side in the left-right direction. Note that outer side in the left-right direction means a direction away from the central axis of the drive shaft 15 in the left-right direction. Inner side in the left-right direction means a direction approaching the central axis of the drive shaft 15 in the left-right direction.
The first intermediate portion 22 is located between the first contact support portion 21 and the first external connection portion 24. The first intermediate portion 22 is arranged on the outer side of the first fixed contact 11 in the longitudinal direction of the movable contact piece 7. The first intermediate portion 22 extends from the first contact support portion 21 in a direction parallel to the moving direction of the movable contact piece 7, that is, in the up-down direction. Specifically, the first intermediate portion 22 extends upward from the first contact support portion 21. The first external connection portion 24 extends to the left from the first intermediate portion 22. The first external connection portion 24 projects to the outer side of the case 2.
The first fixed terminal 5 has a bent shape between the first contact support portion 21 and the first intermediate portion 22 and between the first intermediate portion 22 and the first external connection portion 24. The first contact support portion 21, the first intermediate portion 22, and the first external connection portion 24 may be integrally formed. Alternatively, the first contact support portion 21, the first intermediate portion 22, and the first external connection portion 24 may be separate bodies from each other and connected to each other by a fixing means such as welding.
The second fixed terminal 6 includes a second contact support portion 31, a second intermediate portion 32, and a second external connection portion 34. The second fixed contact 12 is provided in the second contact support portion 31. The second fixed terminal 6 has a shape that is left-right symmetrical with the first fixed terminal 5. The second contact support portion 31, the second intermediate portion 32, and the second external connection portion 34 correspond to the first contact support portion 21, the first intermediate portion 22, and the first external connection portion 24, respectively. Accordingly, a detailed description of the second fixed terminal 6 will be omitted.
The drive device 4 generates a driving force for operating the movable contact piece 7. The drive device 4 operates the movable contact piece 7 by an electromagnetic force. The drive device 4 moves the movable contact piece 7 in the contact direction Z1 and the separating direction Z2. The drive device 4 is arranged below the movable contact piece 7. The drive device 4 includes a coil 41, a spool 42, an iron core 43, a return spring 44, and a yoke 45.
The coil 41 is wound around the spool 42. The coil 41 and the spool 42 are arranged coaxially with the drive shaft 15. The spool 42 has a hole 42a that penetrates in the axial direction of the spool 42. The iron core 43 and the return spring 44 are inserted into the hole 42a of the spool 42. The yoke 45 is connected to the iron core 43.
The yoke 45 includes a first yoke 45a and a second yoke 45b. The first yoke 45a is arranged between the contact device 3 and the spool 42. The second yoke 45b is connected to the first yoke 45a. The second yoke 45b has a U-shape. The second yoke 45b is arranged on both sides of the coil 41 and on the opposite side of the first yoke 45a with respect to the coil 41.
The iron core 43 includes a fixed iron core 43a, a movable iron core 43b, and a ring iron core 43c. The fixed iron core 43a is fixed to the second yoke 45b. The ring iron core 43c is in contact with the first yoke 45a. The movable iron core 43b is separate from the fixed iron core 43a and the ring iron core 43c. The movable iron core 43b is movably arranged in the contact direction Z1 and the separating direction Z2. The movable iron core 43b moves within the ring iron core 43c. The movable iron core 43b is connected to the drive shaft 15. The return spring 44 is arranged between the movable iron core 43b and the fixed iron core 43a. The return spring 44 biases the movable iron core 43b in the separating direction Z2.
Next, the operation of the relay 1 will be described. When the coil 41 is not excited due to no electric current being passed therethrough, the drive shaft 15 is in a pressed state in the separating direction Z2 by the elastic force of the return spring 44 together with the movable iron core 43b. Therefore, the movable contact piece 7 is also in a pressed state in the separating direction Z2, and as shown in
When the coil 41 is excited by an electric current being passed therethrough, the movable iron core 43b moves in the contact direction Z1 against the elastic force of the return spring 44 due to the electromagnetic force of the coil 41. Thereby, the drive shaft 15, the holder 16, and the movable contact piece 7 all move in the contact direction Z1, whereby the first movable contact 13 and the second movable contact 14 assume a closed state in contact with the first fixed contact 11 and the second fixed contact 12.
When the electric current to the coil 41 is stopped and the coil 41 is demagnetized, the drive shaft 15 is pressed in the separating direction Z2 by the elastic force of the return spring 44 together with the movable iron core 43b. For that reason, the movable contact piece 7 is also pressed in the separating direction Z2, whereby the first movable contact 13 and the second movable contact 14 return to the open state.
The first magnet 51 and the second magnet 52 are arranged apart from each other in the left-right direction. The first magnet 51 is arranged on one side of the movable contact piece 7 in the left-right direction. The second magnet 52 is arranged on one side of the movable contact piece 7 in the left-right direction. Specifically, the first magnet 51 is arranged to the left of the movable contact piece 7. The second magnet 52 is arranged to the right of the movable contact piece 7.
The first magnet 51 and the second magnet 52 are arranged so that their same poles face each other. Specifically, the first magnet 51 includes an S-pole surface 51S that opposes the movable contact piece 7 and an N-pole surface 51N on the opposite side of the S-pole surface 51S. The second magnet 52 includes an S-pole surface 52S opposing the movable contact piece 7 and an N-pole surface 52N on the opposite side of the S-pole surface 52S.
The third magnet 53 is arranged opposite the front-back direction with respect to the movable contact piece 7. In the present embodiment, the front-back direction coincides with the width direction of the movable contact piece 7 that intersects the longitudinal direction of the movable contact piece 7. The third magnet 53 includes an N-pole surface 53N opposing the movable contact piece 7 and an S-pole surface 53S on the opposite side of the N-pole surface 53N.
The relay 1 includes a yoke 47. The yoke 47 connects the first magnet 51, the second magnet 52, and the third magnet 53. Specifically, the yoke 47 is connected to the N-pole surface 51N of the first magnet 51, the N-pole surface 52N of the second magnet 52, and the S-pole surface 53S of the third magnet 53.
Due to the arrangement of the first magnet 51, the second magnet 52, and the third magnet 53 as described above, as shown in
Accordingly, when an electric current flows from the first movable contact 13 to the second movable contact 14 (from left to right in
As described above, when the Lorentz forces F1 and F2 or the Lorentz forces F3 and F4 act on an arc, the arc is stretched in the directions indicated by the arrows F1-F4. Thereby, the arc is quickly extinguished. Hereinafter, the direction of the Lorentz force (F 1-F4) acting on the arc by the magnetic force of the first to third magnets 51-53 is referred to as the “first extension direction (F1-F4)”. In the present embodiment, the first extension direction (F1-F4) is the width direction of the movable contact piece, that is, the front-back direction.
Specifically, the first extension direction (F1) is the direction of the Lorentz force acting on an arc at the first contact position P1 by the magnetic fields of the first to third magnets 51-53 when an electric current flows from the first movable contact 13 to the second movable contact 14 in the movable contact piece 7. The first extension direction (F2) is the direction of the Lorentz force acting on an arc at the second contact position P2 by the magnetic fields of the first to third magnets 51-53 when an electric current flows from the first movable contact 13 to the second movable contact 14 in the movable contact piece 7.
The first extension direction (F3) is the direction of the Lorentz force acting on an arc at the first contact position P1 by the magnetic fields of the first to third magnets 51-53 when an electric current flows from the second movable contact 14 to the first movable contact 13 in the movable contact piece 7. The first extension direction (F4) is the direction of the Lorentz force acting on an arc at the second contact position P2 by the magnetic fields of the first to third magnets 51-53 when an electric current flows from the second movable contact 14 to the first movable contact 13 in the movable contact piece 7.
Further, as shown in
For example, when an electric current flows from the first movable contact 13 to the second movable contact 14 in the movable contact piece 7, at the first contact position P1, the Lorentz force F5 heading to the inner side in the left-right direction acts on the arc due to the magnetic field generated by the electric current flowing through the first intermediate portion 22. In this case, a resultant force F1′ of the Lorentz forces F1 and F5 acts on the arc. Accordingly, the arc is stretched in the direction of the resultant force F1′ of the Lorentz forces.
Similarly, at the second contact position P2, an electric current flows through the second intermediate portion 32, whereby the Lorentz force F6 heading to the inner side in the left-right direction acts on the arc at the second contact position P2. Therefore, a resultant force F2′of the Lorentz forces F2 and F6 acts on the arc. Accordingly, the arc is stretched in the direction of the Lorentz force resultant force F2′.
Hereinbelow, the directions of the Lorentz forces F5 and F6 acting on the arc by the magnetic field generated by the electric current flowing in the first intermediate portion 22 are referred to as the second extension directions (F5 and F6). In the present embodiment, the second extension directions (F5, F6) are directions heading to the inner side in the longitudinal direction of the movable contact piece.
Specifically, the second extension direction (F5) is the direction of the Lorentz force acting on the arc at the first contact position P1 due to the magnetic field generated by the electric current flowing in the first intermediate portion 22. The second extension direction (F6) is the direction of the Lorentz force acting on the arc at the second contact position P2 due to the magnetic field generated by the electric current flowing through the second intermediate portion 32.
As shown in
As shown in
The inner case 20 includes a top surface 26, a first side wall 27, and a second side wall 28. The top surface 26 covers the first storage portion 51 in the contact case 18 from above. The first side wall 27 and the second side wall 28 are arranged apart from each other in the front-back direction. The first side wall 27 and the second side wall 28 extend downward from the top surface 26. The first wall portion 61 and the second wall portion 62 are located on the inner surface of the first side wall 27. The third wall portion 63 and the fourth wall portion 64 are provided on the inner surface of the second side wall 28.
The first wall surface 71 is arranged facing the arc-extinguishing space A1. The first wall surface 71 is arranged opposite the first extension direction (F1) with respect to the first movable contact 13 and the first fixed contact 11. That is, when viewed from the front-back direction, the first wall surface 71 overlaps the first movable contact 13 and the first fixed contact 11. The first wall surface 71 has a flat shape extending in the left-right direction.
The second wall surface 72 is arranged facing the arc-extinguishing space A1. The second wall surface 72 is arranged in the second extension direction (F5) with respect to the first wall surface 71. The second wall surface 72 is arranged opposite the first extension direction (F1) with respect to the first movable contact 13 and the first fixed contact 11. That is, when viewed from the front-back direction, the second wall surface 72 overlaps the first movable contact 13 and the first fixed contact 11.
The second wall surface 72 has a flat shape extending in the left-right direction. The second wall surface 72 is arranged farther from the movable contact piece 7 than the first wall surface 71 in the first extension direction (F1). Therefore, in the first extension direction (F1), the distance from the movable contact piece 7 to the second wall surface 72 is larger than the distance from the movable contact piece 7 to the first wall surface 71.
The first connecting wall surface 81 is arranged between the first wall surface 71 and the second wall surface 72. The first connecting wall surface 81 is connected to the first wall surface 71 and the second wall surface 72. The first connecting wall surface 81 extends in the front-back direction, that is, in the first extension direction (F1). The first wall portion 61 has a stepped shape on the first connecting wall surface 81.
The second wall portion 62 has a shape symmetrical to the first wall portion 61 in the left-right direction. The second wall portion 62 is arranged separated from the movable contact piece 7 in the first extension direction (F2) by the arc-extinguishing space A2. The second wall portion 62 is arranged at a position opposing the second contact position P2 in the first extension direction (F2). The second wall portion 62 includes a third wall surface 73, a fourth wall surface 74, and a second connecting wall surface 82. The fourth wall surface 74 is arranged apart from the movable contact piece 7 with respect to the third wall surface 73 in the first extension direction (F2). The third wall surface 73, the fourth wall surface 74, and the second connecting wall surface 82 are symmetrical in the left-right direction with the first wall surface 71, the second wall surface 72, and the first connecting wall surface 81, respectively, and thereby detailed descriptions thereof are omitted.
The fourth wall portion 64 has a shape symmetrical to the third wall portion 63 in the left-right direction. The fourth wall portion 64 is arranged separated from the movable contact piece 7 in the first extension direction (F4) by the arc-extinguishing space A4. The fourth wall portion 64 includes a seventh wall surface 77, an eighth wall surface 78, and a fourth connecting wall surface 84. The eighth wall surface 78 is arranged farther from the movable contact piece 7 than the seventh wall surface 77 in the first extension direction (F4). Because the seventh wall surface 77, the eighth wall surface 78, and the fourth connecting wall surface 84 are symmetrical in the left-right direction with the fifth wall surface 75, the sixth wall surface 76, and the third connecting wall surface 83, respectively, detailed descriptions thereof are omitted.
In the relay 1 according to the first embodiment described above, when the electric current flowing through the contacts is small, the arc is stretched toward the first wall surface 71. Further, when the electric current flowing through the contacts is large, the arc is stretched toward the second wall surface 72.
The starting point O1 of the arc shown in
For example, when the electric current flowing through the contacts is 3000 A, the Lorentz force F5 in the second extension direction (F5) is larger than when the electric current is 100 A. Therefore, the arc is stretched from the starting point O1 of the arc in the direction indicated by the arrow C2 in
Here, the distance from the movable contact piece 7 to the second wall surface 72 is larger than the distance from the movable contact piece 7 to the first wall surface 71. For that reason, when the electric current is large, a space sufficiently large for stretching the arc can be secured between the second wall surface 72 and the movable contact piece 7.
In other words, the distance from the movable contact piece 7 to the first wall surface 71 is smaller than the distance from the movable contact piece 7 to the second wall surface 72. Therefore, even if the electric current is small, the stretched arc can be pressed against the first wall surface 71 with sufficient force. Thereby, the arc can be extinguished appropriately.
As described above, in the relay 1 according to the present embodiment, it is possible to appropriately extinguish an arc in accordance with the magnitude of the electric current flowing through the contacts by appropriately setting the positions of the first wall surface 71 and the second wall surface 72 of the first wall portion 61 with respect to the movable contact piece 7.
The first wall portion 61 is provided in the inner case 20 which is separate from the contact case 18. Accordingly, the formation of the first wall portion 61 becomes easy.
The first wall portion 61 is formed of an arc-extinguishing material that generates an arc-extinguishing gas by the heat of the arc. Therefore, when the arc is pressed against the first wall portion 61 with a sufficient force, the arc can be extinguished more appropriately.
Further, the same effect as that of the first wall portion 61 described above can be obtained for the second to fourth wall portions 62-64.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the invention. For example, the configuration of the drive device 4 may be changed. The shape or arrangement of the coil 41, the spool 42, the iron core 43, the return spring 44, or the yoke 45 may be changed. The shape or arrangement of the case 2 may be changed.
The shape or arrangement of the first fixed terminal 5, the second fixed terminal 6, and the movable contact piece 7 may be changed. For example, the first external connection portion 24 and the second external connection portion 34 may project upward from the case 2. Alternatively, the first external connection portion 24 and the second external connection portion 34 may protrude from the case 2 in the front-back direction. The arrangement or polarity of the first to third magnets 51-53 is not limited to that of the above embodiment, and may be changed.
The first fixed contact 11 may be separate from the first fixed terminal 5 or may be integrated therewith. The second fixed contact 12 may be separate from the second fixed terminal 6 or may be integrated therewith. The first movable contact 13 may be separate from the movable contact piece 7 or may be integrated therewith. The second movable contact 14 may be separate from the movable contact piece 7 or may be integrated therewith.
In the above embodiment, the drive device 4 pulls the drive shaft 15 from the coil 41 side, whereby the movable contact piece 7 moves in the contact direction Z1. Further, when the drive device 4 pushes the drive shaft 15 from the coil 41 side, the movable contact piece 7 moves in the separating direction Z2. However, the operating direction of the drive shaft 15 for opening and closing the contacts may be opposite to that of the above embodiment. That is, the movable contact piece 7 may move in the separating direction Z2 by the drive device 4 pulling the drive shaft 15 to the coil 41 side. The movable contact piece 7 may move in the contact direction Z1 by the drive device 4 pushing the drive shaft 15 from the coil 41 side. That is, the contact direction Z1 and the separating direction Z2 may be turned upside down from the above-described embodiment.
The shape or arrangement of the first to fourth wall portions 61-64 may be changed. The shape or arrangement of the first to eighth wall surfaces 71-78 may be changed. The shape or arrangement of the first to fourth connecting wall surfaces 81-84 may be changed. For example, in the above embodiment, the first to fourth wall portions 61-64 are integrally provided on the inner case 20. However, the first to fourth wall portions 61-64 may be separate bodies from each other. The first to fourth wall portions 61-64 may be provided separately from the inner case 20. A part of the first to fourth wall portions 61-64 may be omitted.
The first wall portion 61 may have a plurality of stepped shapes due to the first wall surface 71, the first connecting wall surface 81, and the second wall surface 72. As for the first connecting wall surface 81, the distance from the movable contact piece 7 to the first connecting wall surface 81 may be larger than the distance from the movable contact piece 7 to the first wall surface 71, and may be smaller than the distance from the movable contact piece 7 to the second wall surface 72. In this case, as shown by the arrow C3, when the arc is stretched between the first wall surface 71 and the second wall surface 72, the arc can be appropriately extinguished.
In this case, when the electric current is large but the voltage is small, the stretched arc can be pressed against the second wall surface 72 with sufficient force. For example, when an electric current of 800 V and 400 A flows through the contacts, the Lorentz force F5 in the second extension direction is smaller than the Lorentz force F1 in the first extension direction. For that reason, the arc is stretched from the starting point O1 of the arc in the direction indicated by the arrow C4 in
For example, when an electric current of 400 V and 3,500 A flows through the contacts, the Lorentz force F5 in the second extension direction is larger than when the electric current is 400 A. For that reason, the arc is stretched from the starting point O1 of the arc in the direction indicated by the arrow C5 in
Although modifications of the first wall portion 61 have been described above, the second to fourth wall portions 62-64 may be modified in the same manner as the aforementioned modifications.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-157816 | Aug 2018 | JP | national |
This application is the U.S. National Phase of International Application No. PCT/JP2019/005925, filed on Feb. 18, 2019. This application claims priority to Japanese Patent Application No. 2018-157816, filed Aug. 24, 2018. The contents of that application are incorporated by reference herein in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/005925 | 2/18/2019 | WO | 00 |
