Relay

Abstract

Relay (1) comprising: a movable contact piece (10), including a movable contact (16, 17); a fixed terminal (11, 12), including a fixed contact (14, 15) arranged facing the movable contact (16, 17); a drive device (4) designed to move the movable contact piece (16, 17) in a contact direction (Z1) in which the movable contact (16, 17) is arranged close to the fixed contact (14, 15), and an opening direction (Z2) in which the movable contact (16, 17) separates from the fixed contact (14, 15);a first yoke (41) arranged in the contact direction (Z1) to the movable contact piece (16, 17), and a second yoke (42) arranged in the opening direction (Z2) to the movable contact piece (16, 17), wherein the first yoke (41) and the second yoke (42) are designed to generate a magnetic force that attracts the first yoke (41) and the second yoke (42) to each other when the movable contact (16, 17) touches the fixed contact (14, 15) and is energized, and the first yoke (41) and the second yoke (42) are arranged such that they do not touch each other, allowing the movable contact piece (16, 17) to touch the fixed terminal (11, 12) in a state in which the movable contact (16, 17) and the fixed contact (14, 15) melt.

Description

TECHNICAL AREA This invention relates to a relay. STATE OF THE ART There is a relay that includes a movable contact, a fixed terminal, and an actuator. The movable contact includes a movable contact. The fixed terminal includes a fixed contact. The movable contact faces the fixed contact. The actuator moves the movable contact in a contact direction and an opening direction. When the movable contact moves in the contact direction, the movable contact touches the fixed contact. When the movable contact moves in the opening direction, the movable contact is separated from the fixed contact. When the movable contact touches the fixed contact, an electric current flows between them. At this point, an electromagnetic repulsion force is generated between the movable and fixed contacts due to the current flowing between them. This electromagnetic repulsion force acts in the opening direction of the movable and fixed contacts. Therefore, the contact pressure between the movable and fixed contacts is reduced by this electromagnetic repulsion force. Therefore, the electromagnetic relay described in patent document 1 provides an upper yoke and a lower yoke. The upper yoke is located above the movable contact. The lower yoke is located below the movable contact. When an electric current flows between the movable contact and the fixed contact, the upper yoke and the lower yoke form a magnetic circuit to generate a magnetic force that attracts the upper yoke and the lower yoke to each other. This improves the contact pressure between the movable contact and the fixed contact against the electromagnetic repulsion force. QUOTE LIST Patent literature JP 6 358 442 B1 discloses a contact device and an electromagnetic relay equipped therewith. The contact device comprises a contact block with a fixed terminal having a fixed contact and a movable contactor with a movable contact. A drive block with a drive shaft drives the movable contactor so that the movable contact can come into contact with and be separated from the fixed contact. The contact block comprises a biasing section that biases the movable contactor in one direction of the drive shaft, and a yoke located at least on the opposite side of the movable contactor in the direction of the drive shaft when the movable contact is in contact with the fixed contact. The biasing section includes a biasing end configured such that the biasing force is exerted on the movable contactor by pressing on an element other than the yoke.DE 692 19 890 T2 discloses an electromagnetically actuated DC switching relay element with a contact chamber, an armature assembly, a movable armature shaft, and stationary and movable contact devices or contacts arranged within a contact chamber. Essential are dead-of-travel devices between the armature shaft and the movable contact devices, which ensure that electrical contact between the movable contact devices and the stationary contacts is closed before the armature reaches its end position and is only broken again after an accelerated start-up of the armature. The dead-of-travel devices comprise a stop element, an axially offset spring seat, a contact disc that is slidable on the armature shaft, and a follow-up spring that pre-tensions the contact disc. The publication also describes how the melting ("pudding") of the contacts can occur in the event of arcing.This can lead to the formation of craters on the contact surfaces if material melts away or if molten contact material hardens upon cooling. Furthermore, puddling can cause the contacts to weld together, making separation difficult. The occurrence of arcing and the associated puddling or welding of the contacts are undesirable, as they can impair the relay contacts, lead to dielectric breakdown, and ultimately result in relay failure. JP 2014 - 232 669 A discloses a contact device in which a movable contact is pressed against a fixed contact by a contact spring. The spring is surrounded by a cylindrical protective element that completely encloses it and protects it from external influences. A retaining element supports both the spring and the movable contact and is moved between the open and closed positions by a drive mechanism, with the protective element engaging in a groove of the movable contact when closing. This arrangement prevents particles or foreign matter from an arc-melted contact from entering the space between the contact spring and the contact spring. BRIEF SUMMARY OF THE INVENTION Technical task If an overcurrent flows between the fixed and movable contacts, both can melt and fail. In this case, excitation between the movable and fixed contacts can be maintained if the movable contact continues to move in the contact direction and touches the fixed terminal. However, in the aforementioned electromagnetic relay, the upper and lower yokes are positioned facing each other. Therefore, if both the fixed and movable contacts fail due to an overcurrent, the lower yoke will touch the upper yoke, restricting the movement of the movable contact in the contact direction. Consequently, if both the fixed and movable contacts fail, excitation between the movable contact and the fixed terminal cannot be maintained. One aim of this invention is to improve the contact pressure of contacts by means of a yoke in a relay and to ensure excitation between a movable contact piece and a fixed terminal, even if the contacts are lost. Solution to the task A relay, according to one aspect, includes a movable contact, a fixed terminal, a drive mechanism, a first yoke, and a second yoke. The movable contact includes a movable contact. The fixed terminal includes a fixed contact. The fixed contact faces the movable contact. The drive mechanism moves the movable contact in a contact direction and an opening direction. The contact direction is the direction in which the movable contact is close to the fixed contact. The opening direction is the direction in which the movable contact is separated from the fixed contact. The first yoke is arranged relative to the movable contact in the contact direction. The second yoke is arranged relative to the movable contact in the opening direction.The first and second yokes are designed to generate a magnetic force that attracts them to each other when the movable contact touches the fixed contact and is energized. The first and second yokes are arranged so that they do not touch each other, allowing the movable contact to touch the fixed contact in a state where both the movable and fixed contacts are disengaged. In this type of relay, the first and second yokes generate the magnetic force to attract each other. This presses the movable contact in the contact direction, improving the contact pressure. Furthermore, the first and second yokes are positioned so that they do not touch each other, allowing the movable contact to make contact with the fixed terminal even if either the movable contact or the fixed contact is lost. Therefore, the excitation of both the movable contact and the fixed terminal is maintained even if either the movable contact or the fixed contact is lost. In the direction of movement of the movable contact piece, the distance between the first yoke and the second yoke can be greater than the sum of the lengths of the fixed contact and the movable contact if the movable contact touches the fixed contact. Since the second yoke is far from the first yoke, the movement of the movable contact piece in the contact direction is not restricted by the first and second yokes. Consequently, the movable contact piece can touch the fixed connection if both the fixed and movable contacts are lost. The second yoke can be arranged so that it is separate from the first yoke when the movable contact and the fixed contact are lost and the movable contact piece touches the fixed terminal. In this case, the movement of the movable contact piece in the contact direction is not restricted by the first and second yokes when the movable contact and the fixed contact are lost and the movable contact piece touches the fixed terminal. Consequently, the movable contact piece can touch the fixed terminal when the fixed contact and the movable contact are lost. The second yoke can enclose a first wall section and a second wall section. The first and second wall sections can be spaced apart. If the movable contact and the fixed contact are lost, and the movable contact touches the fixed connection, the first yoke can be positioned between the first and second wall sections. In this case, the movement of the movable contact in the contact direction is not restricted by the first and second yokes, as the first yoke extends between the first wall section and the second wall section of the second yoke. Consequently, the movable contact can touch the fixed connection if the fixed and movable contacts are lost. The first wall section and the second wall section can be spaced apart in a first direction perpendicular to the direction of movement of the movable contact piece. In this first direction, the first yoke can be smaller than the distance between the first wall and the second wall. In this case, the movement of the movable contact piece in the contact direction is not restricted by the first and second yokes, since the first yoke extends between the first and second wall sections. Consequently, the movable contact piece can touch the fixed connection if both the fixed and movable contacts are lost. Advantageous effects of the invention According to the invention, the contact pressure of the contacts in a relay can be improved by the yoke, and even if the contacts are lost, the excitation between the movable contact piece and the fixed connection can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a side view of a relay in an open state according to one embodiment. Fig. 2 shows a side view showing the relay in a closed state. Fig. 3 shows a cross-sectional view of a contact device, viewed from a left-right direction. Fig. 4 shows an enlarged view of the contact device with a movable contact in a closed position. Fig. 5 shows an enlarged view of the contact device in a state where the movable contact and the fixed contact are disengaged. Fig. 6 shows a diagram illustrating part of the relay structure according to a first embodiment. Fig. 7 shows a diagram illustrating part of the relay structure according to the first embodiment. Fig. 8 shows a diagram illustrating part of the relay structure according to the first embodiment.Figure 9 shows a diagram illustrating part of the relay structure according to a second embodiment. Figure 10 shows a diagram illustrating part of the relay structure according to a third embodiment. Figure 11 shows a diagram illustrating part of the relay structure according to a fourth embodiment. Figure 12 shows a diagram illustrating part of the relay structure according to a fifth embodiment. DESCRIPTION OF EXECUTION FORMS In the following, a relay 1 according to one embodiment is described with reference to the drawings. Fig. 1 shows a side view illustrating the relay 1 according to the embodiment. As shown in Fig. 1, the relay 1 includes a contact device 2, a receptacle 3, and a drive device 4. In the following description, each direction up / down / left / right is synonymous with each direction up / down / left / right in Fig. 1. In particular, a direction from the drive device 4 to the contact device 2 is defined as upwards. Furthermore, a direction from the contact device 2 to the drive device 4 is defined as downwards. In Fig. 1, a direction that intersects the vertical direction is defined as the left-right direction. A direction that intersects the vertical direction and the left-right direction is also defined as the forward-backward direction. The forward-backward direction is a direction that is perpendicular to the paper surface in Fig. 1. However, these directions are defined to make the explanation clearer and do not restrict the orientation of the relay 1. The contact device 2 is arranged in the receptacle 3. The contact device 2 includes a first fixed terminal 11, a second fixed terminal 12, a movable contact piece 10, and a drive shaft 19. The first fixed terminal 11 and the second fixed terminal 12 are made of a conductive material such as copper. The first fixed connection 11 includes a first fixed contact 14, a first contact carrier section 21, and a first external connection section 22. The first fixed contact 14 is connected to the first contact carrier section 21. The first fixed contact 14 has a shape that protrudes from the first contact carrier section 21. The first contact carrier section 21 faces the movable contact 10. A first external connection section 22 is connected to the first contact carrier section 21. The first external connection section 22 projects outwards from the receptacle 3. The second fixed terminal 12 includes a second fixed contact 15, a second contact carrier section 23, and a second external terminal section 24. The second fixed contact 15 is connected to the second contact carrier section 23. The second fixed contact 15 has a shape that protrudes from the second contact carrier section 23. The first fixed contact 14 and the second fixed contact 15 are spaced apart from each other in the left-right direction. The second contact carrier section 23 faces the movable contact piece 10. The second external connection section 24 is connected to the second contact carrier section 23. The second external connection section 24 projects outwards from the receptacle 3. Specifically, the first external connection section 22 and the second external connection section 24 project from the receptacle 3 in a left-right direction. However, the first external connection section 22 and the second external connection section 24 can also project upwards from the receptacle 3. Alternatively, the first external connection section 22 and the second external connection section 24 can project from the receptacle 3 in a forward-backward direction. The movable contact piece 10 is made of a conductive material such as copper. The movable contact piece 10 is movably arranged in a contact direction Z1 and an opening direction Z2. The contact direction Z1 is a direction in which the movable contact piece 10 is arranged close to the first fixed terminal 11 and the second fixed terminal 12 (upwards in Fig. 1). The opening direction Z2 is a direction in which the movable contact piece 10 is separated from the first fixed terminal 11 and the second fixed terminal 12 (downwards in Fig. 1). The movable contact element 10 includes a contact element body 13, a first movable contact 16, and a second movable contact 17. The contact element body 13 extends in a left-right direction. In this embodiment, one longitudinal direction of the contact element body 13 coincides with the left-right direction. The contact element body 13 is arranged such that it faces the first contact carrier section 21 of the first fixed terminal 11 and the second contact carrier section 23 of the second fixed terminal 12 in a vertical direction. The first movable contact 16 and the second movable contact 17 are connected to the contact piece main body 13. The first movable contact 16 and the second movable contact 17 have a shape that protrudes from the contact piece main body 13. The first movable contact 16 and the second movable contact 17 are spaced apart from each other in the left-right direction. The first movable contact 16 faces the first fixed contact 14 in a vertical direction. The second movable contact 17 faces the second fixed contact 15 in a vertical direction. The drive shaft 19 carries the movable contact piece 10. The drive shaft 19 is movably arranged in the contact direction Z1 and the opening direction Z2 together with the movable contact piece 10. The drive shaft 19 extends in the vertical direction. The movable contact piece 10 is provided with a hole 13a. The drive shaft 19 is inserted into the hole 13a. The movable contact piece 10 is movable relative to the drive shaft 19 in the contact direction Z1 and the opening direction Z2. The drive device 4 actuates the movable contact piece 10 by means of an electromagnetic force. The drive device 4 moves the drive shaft 19 in the contact direction Z1 and the opening direction Z2. Consequently, the drive device 4 moves the movable contact piece 10 in the contact direction Z1 and the opening direction Z2. The drive device 4 includes a movable iron core 31, a coil 32, a fixed iron core 33, a yoke 34, and a return spring 35. The movable iron core 31 is connected to the drive shaft 19. The movable iron core 31 is designed to move in the contact direction Z1 and the opening direction Z2. When the coil 32 is energized, the coil 32 generates an electromagnetic force that moves the movable iron core 31 in the contact direction Z1. The fixed iron core 33 is arranged so that it faces the movable iron core 31. The return spring 35 is arranged between the movable iron core 31 and the fixed iron core 33. The return spring 35 forces the movable iron core 31 in the opening direction Z2. The yoke 34 is arranged to surround the coil 32. The yoke 34 is located on a magnetic circuit generated by the coil 32. The yoke 34 is positioned above the coil 32, on the side of the coil 32, and below the coil 32. The operation of relay 1 is described below. When coil 32 is not energized, the drive device 4 is not magnetized. In this case, the drive shaft 19, together with the movable iron core 31, is pressed into the opening direction Z2 by the elastic force of the return spring 35. Therefore, the movable contact 10 is in the open position shown in Fig. 1. In this state, the movable contact 10 is also pressed into the opening direction Z2 by the drive shaft 19. The movable contact 10 is in the open position, and the first movable contact 16 and the second movable contact 17 are separated from the first fixed contact 14 and the second fixed contact 15, respectively. When the coil 32 is energized, the drive device 4 is magnetized. In this case, the movable iron core 31 moves in the contact direction Z1 against the elastic force of the return spring 35 due to the electromagnetic force of the coil 32. Consequently, the drive shaft 19 and the movable contact piece 10 both move in the contact direction Z1. The movable contact piece 10 then moves to the closed position shown in Fig. 2. When the movable contact piece 10 is in the closed position, the first movable contact 16 touches the first fixed contact 14, and the second movable contact 17 touches the second fixed contact 15. When the current to coil 32 is interrupted and the coil is demagnetized, the movable iron core 31 is pressed in the opening direction Z2 by the elastic force of the return spring 35. Consequently, the drive shaft 19 and the movable contact piece 10 both move in the opening direction Z2. As a result, the first movable contact 16 is separated from the first fixed contact 14, and the second movable contact 17 is separated from the second fixed contact 15. As shown in Figures 1 and 2, the relay 1 comprises a first yoke 41 and a second yoke 42. The first yoke 41 is arranged relative to the movable contact piece 10 in the contact direction Z1. This means that the first yoke 41 is positioned above the movable contact piece 10. The second yoke 42 is arranged relative to the movable contact piece 10 in the opening direction Z2. This means that the second yoke 42 is positioned below the movable contact piece 10. The first yoke 41 is fixed to the drive shaft 19. The second yoke 42 is designed to move relative to the drive shaft 19. Fig. 3 shows a cross-sectional view of the contact device 2, viewed from the left-right direction. As shown in Fig. 3, the second yoke 42 encloses a first wall section 43, a second wall section 44, and a bottom section 45. The first wall section 43 and the second wall section 44 can be spaced apart from each other in a back-forward direction. The forward-backward direction is an example of a first direction, which is perpendicular to the direction of movement of the movable contact piece 10. The left-right direction can be defined as an example of a second direction, which is perpendicular to the direction of movement of the movable contact piece 10. The movable contact piece 10 is arranged between the first wall section 43 and the second wall section 44 in a forward-backward direction. The movable contact piece 10 is smaller than the gap G1 between the first wall section 43 and the second wall section 44 in a forward-backward direction. Therefore, the movable contact piece 10 can be inserted into the gap G1 between the first wall section 43 and the second wall section 44, as shown in Fig. 3A. The bottom section 45 connects the lower part of the first wall section 43 and the lower part of the second wall section 44. The bottom section 45 encloses a hole 45a. The drive shaft 19 is inserted into the hole 45a. The drive shaft 19 encloses a stop 46. The stop 46 is connected to the drive shaft 19. The stop 46 can be integrated with the drive shaft 19. Alternatively, the stop 46 can be provided separately from the drive shaft 19. The stop 46 restricts the downward movement of the second yoke 42 towards the drive shaft 19. In the forward-backward direction, the gap G1 between the first wall section 43 and the second wall section 44 is smaller than that of the first bay 41. In other words, the first bay 41 is larger in the forward-backward direction than the gap G1 between the first wall section 43 and the second wall section 44. The first wall section 43 and the second wall section 44 are located below the first bay 41. The first wall section 43 and the second wall section 44 face the first bay 41 in the vertical direction. In other words, at least a portion of the first wall section 43 and the second wall section 44 overlaps the first bay 41 when viewed from the vertical direction. Relay 1 includes a spring 47. The spring 47 is arranged between the movable contact piece 10 and the second yoke 42. Specifically, the spring 47 is arranged between the bottom section 45 of the second yoke 42 and the movable contact piece 10. The first yoke 41 and the second yoke 42 are designed to generate a magnetic force that attracts the first yoke 41 and the second yoke 42 to each other when the movable contacts 16 and 17 touch the fixed contacts 14 and 15 and are energized. Fig. 3A shows a state in which the movable contacts 16 and 17 are in contact with the fixed contacts 14 and 15, and the first yoke 41 and the second yoke 42 are not attracted to each other. When the first yoke 41 and the second yoke 42 are attracted to each other by a magnetic force, the second yoke 42 moves upwards as shown in Fig. 3B. At this point, the movable contact piece 10 cannot move upwards because the movable contacts 16 and 17 are touching the fixed contacts 14 and 15. Therefore, the spring 47 is compressed by the upward movement of the second yoke 42. The elastic force of the spring 47 pushes the movable contact piece 10 upwards, i.e., in the contact direction Z1. This increases the contact pressure of the contacts. Fig. 4 shows an enlarged view of the contact device 2 in which the movable contact piece 10 is in the closed position. When the movable contact piece 10 is in the closed position, the distance D3 between the first yoke 41 and the second yoke 42 in the vertical direction, as shown in Fig. 4, is greater than the sum D1 of the lengths of the first fixed contact 14 and the first movable contact 16 in the vertical direction (hereinafter referred to as the "first contact length D1"). When the movable contact piece 10 is in the closed position, the distance D3 between the first yoke 41 and the second yoke 42 in the vertical direction is greater than the sum D2 of the lengths of the second fixed contact 15 and the second movable contact 17 in the vertical direction (hereinafter referred to as the "second contact length D2").When the movable contact piece 10 is in the closed position, the vertical distance D4 between the first yoke 41 and the movable contact piece 10 is greater than the first contact length D1. When the movable contact piece 10 is in the closed position, the vertical distance D4 between the first yoke 41 and the movable contact piece 10 is greater than the second contact length D2. When the movable contact piece 10 is in the closed position, the vertical distance D3 between the first yoke 41 and the second yoke 42 is greater than the vertical distance D4 between the first yoke 41 and the movable contact piece 10. In a relay, the movable contacts 16 and 17 and the fixed contacts 14 and 15 can fail due to an overcurrent flowing through them. Fig. 5 shows an enlarged view of the contact assembly 2 in a state where the movable contacts 16 and 17 and the fixed contacts 14 and 15 fail. When the movable contacts 16 and 17 and the fixed contacts 14 and 15 fail, the movable contact 10 moves further upward from the closed position. As shown in Fig. 5, the movable contact 10 then contacts the fixed terminals 11 and 12. Furthermore, as the movable contact 10 moves upward, the second yoke 42 also moves upward by being attracted by the first yoke 41. According to the description above, the distance D3 between the first yoke 41 and the second yoke 42 is greater than the first contact length D1 and greater than the second contact length D2. Therefore, as shown in Fig. 5, the second yoke 42 is separated from the first yoke 41 in a state where the movable contact piece 10 touches the fixed terminals 11 and 12 and the first yoke 41 and the second yoke 42 are not in contact with each other. In relay 1 according to the embodiment described above, the first yoke 41 and the second yoke 42 generate a magnetic force that attracts them to each other when the movable contact piece 10 is in the closed position. Therefore, the movable contact piece 10 is pressed in the contact direction Z1. This improves the contact pressure of the contacts. By arranging the first yoke 41 and the second yoke 42 as described above, the movable contact 10 can touch the first fixed terminal 11 if the first fixed contact 14 and the first movable contact 16 are lost. Consequently, stable excitation can be ensured even if the first fixed contact 14 and the first movable contact 16 are lost. Furthermore, if the second fixed contact 15 and the second movable contact 17 are lost, the movable contact 10 can touch the second fixed terminal 12. Consequently, stable excitation can also be ensured even if the second fixed contact 15 and the second movable contact 17 are lost. Although one embodiment of this invention has been described above, this invention is not limited to the embodiment described above, and various variants are possible without deviating from the concept of the invention. In the embodiment described above, the drive device 4 pushes the drive shaft 19 from the side of the drive device 4, causing the movable contact piece 10 to move in the contact direction Z1. Furthermore, the movable contact piece 10 moves in the opening direction Z2 when the drive device 4 pulls the drive shaft 19 towards the drive device 4. However, the direction of actuation of the drive shaft 19 for opening and closing the contacts can be opposite to that described above. That is, the movable contact piece 10 can move in the contact direction Z1 by pulling the drive shaft 19 towards the drive device 4. The movable contact piece 10 can move in the opening direction Z2 by pushing the drive shaft 19 from the side of the drive device 4.This means that the contact direction Z1 and the opening direction Z2 can be arranged opposite to those in the embodiment above. In this case, the first yoke 41 and the second yoke 42 can be arranged in reverse to the embodiment above. The shapes or arrangements of the first fixed terminal 11, the second fixed terminal 12, and the movable contact piece 10 may be changed. The shape or arrangement of the movable iron core 31, the coil 32, the fixed iron core 33, or the yoke 34 may be changed. The shapes or arrangements of the first fixed contact 14, the second fixed contact 15, the first movable contact 16, and the first fixed contact 14 may be changed. For example, the first fixed contact 14 can be provided separately from the first contact carrier section 21. Alternatively, the first fixed contact 14 can be integrated with the first contact carrier section 21. The second fixed contact 15 can be provided separately from the second contact carrier section 23. Alternatively, the second fixed contact 15 can be integrated with the second contact carrier section 23. The first movable contact 16 and the second movable contact 17 can be provided separately from the contact body 13. Alternatively, the first movable contact 16 and the second movable contact 17 can be integrated with the contact body 13. The shape or arrangement of the first yoke 41 and the second yoke 42 can be modified. Figures 6, 7 to 8 show views illustrating the design of the relay 1 according to the first embodiment. Figures 6A and 7 show a portion of the relay 1 in which the movable contact 10 is in the closed position. As shown in Figure 6A, the first yoke 41 of the relay 1 according to the first embodiment is smaller than the gap G1 between the first wall section 43 and the second wall section 44 in the forward-backward direction. The first yoke 41 can therefore be inserted into the gap G1 between the first wall section 43 and the second wall section 44. In other words, the first yoke 41 does not overlap the first wall section 43 and the second wall section 44 when viewed from the vertical direction. As shown in Fig. 7, the vertical distance D3 between the first yoke 41 and the second yoke 42 can be smaller than the first contact length D1 when the movable contact piece 10 is in the closed position. When the movable contact piece 10 is in the closed position, the vertical distance D3 between the first yoke 41 and the second yoke 42 can be smaller than the second contact length D2. When the movable contact piece 10 is in the closed position, the vertical distance D3 between the first yoke 41 and the second yoke 42 is smaller than the vertical distance D4 between the first yoke 41 and the movable contact piece 10. This could be correct. Figures 6B and 8 show a portion of relay 1 when the movable contacts 16 and 17 and the fixed contacts 14 and 15 are disengaged. When the movable contacts 16 and 17 and the fixed contacts 14 and 15 are disengaged, the movable contact 10 moves further upwards from the closed position. As shown in Figure 8, the movable contact 10 consequently contacts the fixed terminals 11 and 12. Furthermore, as the movable contact 10 moves upwards, the second yoke 42 also moves upwards, being attracted by the first yoke 41. According to the description above, the first yoke 41 can therefore be inserted into the gap G1 between the first wall section 43 and the second wall section 44. Thus, as shown in Fig. 6B, the first yoke 41 is inserted between the first wall section 43 and the second wall section 44 in a state where the movable contact piece 10 contacts the fixed terminals 11 and 12. Consequently, the movable contact piece 10 can contact the fixed terminals 11 and 12 without being obstructed by the first yoke 41 and the second yoke 42. Fig. 9 shows a diagram illustrating part of relay 1 according to the second embodiment. As shown in Fig. 9, the second yoke 42 can be fixed to the movable contact piece 10. The second yoke 42, together with the movable contact piece 10, can be moved vertically relative to the drive shaft 19. In this case, the spring 47 can be omitted. Other configurations correspond to those of the embodiment described above. Fig. 10 shows a diagram illustrating part of relay 1 according to the third embodiment. As shown in Fig. 10, the second yoke 42 can be fixed to the movable contact piece 10. The second yoke 42 can be movable in the vertical direction relative to the drive shaft 19, together with the movable contact piece 10. In this case, the spring 47 can be omitted. Other configurations correspond to those of the first embodiment. In the embodiment above, the first movable contact 16 and the second movable contact 17 have a shape that protrudes from the contact element body 13. However, as in the fourth embodiment shown in Fig. 11, the first movable contact 16 and the second movable contact 17 can be provided flush with the contact element body 13. That is, the first movable contact 16 can be part of the contact element body 13 that contacts the first fixed contact 14. The second movable contact 17 can be part of the contact element body 13 that contacts the second fixed contact 15. In the embodiment above, the first fixed contact 14 has a shape that protrudes from the first contact carrier section 21. The second fixed contact 15 has a shape that protrudes from the second contact carrier section 23. However, as in the fifth embodiment shown in Fig. 12, the first fixed contact 14 can be provided flush with the first contact carrier section 21. The second fixed contact 15 can also be provided flush with the second contact carrier section 23. That is, the first fixed contact 14 can be part of the first contact carrier section 21 that contacts the first movable contact 16. The second fixed contact 15 can be part of the second contact carrier section 23 that contacts the second movable contact 17. INDUSTRIAL APPLICATION According to the invention, the contact pressure of the contacts in a relay can be improved by the yoke, and even if the contacts are lost, the excitation between the movable contact piece and the fixed connection can be ensured. LIST OF REFERENCE MARKS 4 Drive device 10 Movable contact piece 11, 12 Fixed terminals 14, 15 Fixed contacts 16, 17 Movable contacts 41 First yoke 42 Second yoke 43 First wall 44 Second wall

Claims

Relay (1) comprising: a movable contact piece (10), including a movable contact (16, 17); a fixed terminal (11, 12), including a fixed contact (14, 15) arranged facing the movable contact (16, 17); a drive device (4) designed to move the movable contact piece (16, 17) in a contact direction (Z1) in which the movable contact (16, 17) is arranged close to the fixed contact (14, 15), and an opening direction (Z2) in which the movable contact (16, 17) separates from the fixed contact (14, 15);a first yoke (41) arranged in the contact direction (Z1) to the movable contact piece (16, 17), and a second yoke (42) arranged in the opening direction (Z2) to the movable contact piece (16, 17), wherein the first yoke (41) and the second yoke (42) are designed to generate a magnetic force that attracts the first yoke (41) and the second yoke (42) to each other when the movable contact (16, 17) touches the fixed contact (14, 15) and is energized, and the first yoke (41) and the second yoke (42) are arranged such that they do not touch each other, allowing the movable contact piece (16, 17) to touch the fixed terminal (11, 12) in a state in which the movable contact (16, 17) and the fixed contact (14, 15) melt. Relay (1) according to claim 1, wherein in one direction of movement of the movable contact piece a distance between the first yoke (41) and the second yoke (42) is greater than a sum of lengths of the fixed contact (14, 15) and the movable contact (16, 17) when the movable contact (16, 17) touches the fixed contact (14, 15). Relay (1) according to claim 1 or 2, wherein the second yoke (42) is arranged such that it is separated from the first yoke (41) when the movable contact (16, 17) and the fixed contact (14, 15) melt and the movable contact piece (10) touches the fixed terminal (11, 12). Relay (1) according to claim 1, wherein the second yoke (42) includes a first wall section and a second wall section, the first wall section (43) and the second wall section (44) are spaced apart from each other, and the first yoke (41) is arranged such that it is positioned between the first wall section (43) and the second wall section (44) when the movable contact (16, 17) and the fixed contact (14, 15) melt and the movable contact piece (10) touches the fixed terminal (11, 12). Relay (1) according to claim 4, wherein the first wall section (43) and the second wall section (44) are spaced apart from each other in a first direction perpendicular to the direction of movement of the movable contact piece (10), and the first yoke (41) is smaller in the first direction than the gap (G1) between the first wall section (43) and the second wall section (44).

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