Electromagnetic relay

Abstract

Electromagnetic relay with: an excitation coil (12) which generates a magnetic field during a power supply; a movable core (16) which is driven by the magnetic field generated by the excitation coil (12); a movable element (22) which has a movable contact (25) and moves to follow the driven movable core (16); a plurality of fixed terminals (26, 28), each of which has a fixed contact (27, 29) that contacts the movable contact (25) during the supply of energy to the excitation coil (12); a base (20) comprising an electrically insulating resin which holds the majority of fixed terminals (26, 28); a fixed yoke (31, 31A, 31B) formed from a magnetic material and supported by at least one of the plurality of fixed terminals (26, 28); and a movable yoke (30, 30A, 30B) formed from a magnetic material and arranged to face the stationary yoke (31, 31A, 31B), wherein the movable yoke (30, 30A, 30B) is in contact with the movable element (22) and moves together with the movable element (22), wherein a direction in which the movable element (22) moves during the supply of energy to the excitation coil (12) is a contact movement direction (A); and a part of the fixed yoke (31, 31A, 31B) projects into a space between the plurality of fixed terminals (26, 28) when the fixed yoke (31, 31A, 31B) is viewed along the contact movement direction (A); and wherein the fixed yoke (31, 31A, 31B) has a plate shape and the fixed connection (26, 28) between the movable element (22) and the fixed yoke (31, 31A, 31B) is in the contact movement direction (A).

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is based on Japanese Patent Application No. 2014-195400, filed on September 25, 2014, and incorporates the same herein by reference. TECHNICAL FIELD

[0002] The present invention relates to an electromagnetic relay that opens or closes an electric circuit by causing a movable contact and a fixed contact to come into or out of contact with each other. BACKGROUND TECHNOLOGY

[0003] In a conventional electromagnetic relay, two fixed terminals having a fixed contact are positioned and fixed, and an electrical circuit is opened or closed by moving a movable element having a movable contact such that the movable contact and the fixed contact come into or out of contact with each other.

[0004] An electromagnetic repulsion force (hereinafter referred to as an electromagnetic contact point repulsion force) is generated at a contact point between the movable contact and the fixed contact by an electric current flowing in a reverse direction in a portion where the movable contact and the fixed contact face each other. The electromagnetic contact point repulsion force works to separate the movable contact and the fixed contact from each other.

[0005] As in Fig. As shown in Fig. 8, a movable yoke 93 and a fixed yoke 94 are fixed to a shaft 92 integral with a movable core 90 and fixed to a movable member 91. The movable member 91 is sandwiched between the movable yoke 93 and the fixed yoke 94. A yoke attraction force is generated between the movable yoke 93 and the fixed yoke 94 by a magnetic flux flowing in the movable yoke 93 and the fixed yoke 94 when the movable member 91 and a fixed terminal 95 contact each other. The movable yoke 93 pushes the movable member 91 toward the fixed terminal 95 to limit contact separation caused by the electromagnetic contact point repulsion force (for example, refer to Patent Document 1).

[0006] The movable yoke 93 is slidably mounted on the shaft 92, and the fixed yoke 94 is fixed to the shaft 92. The movable element 91 and the movable yoke 93 are urged toward the fixed yoke 94 and the fixed terminal 95 by a pressure contact spring 96 attached to the shaft 92. The movable core 90 is attracted toward a fixed core 98 by an electromagnetic attraction force generated when an excitation coil 97 is energized.

[0007] If only the yoke attraction force is increased without increasing the electromagnetic attraction force in order to limit the separation caused by the electromagnetic contact point repulsion force even in a short circuit in which a large amount of electric current flows, a phenomenon described below may occur.

[0008] After the movable yoke 93 has moved the movable element 91 to the fixed terminal 95 (a situation which is Fig. 8), the fixed yoke 94 is attracted toward the movable yoke 93 by the yoke attraction force, and the movable core 90 and the shaft 92 integral with the fixed yoke 94 are urged in a direction opposite to the attraction force caused by the electromagnetic attraction force.

[0009] When the yoke attraction force is greater than the electromagnetic force, the movable core 90 moves away from the stationary core 98, and the electromagnetic attraction force decreases accordingly. As a result, the contacts can be separated from each other.

[0010] If the electromagnetic force is also increased and set to be greater than the yoke attraction force, the phenomenon described above does not occur. In this case, however, the excitation coil 97 may be large in size to increase the electromagnetic attraction force.

[0011] On the other hand, Patent Document 2 discloses an electromagnetic relay in which a fixed yoke is fixed to a housing. According to this, since the fixed yoke is immovable, the fixed yoke is not attracted toward the movable yoke by a yoke attraction force after the movable yoke moves the movable element toward a fixed terminal, and thus, contact separation can be limited.

[0012] However, a contact space in which the movable element and the fixed terminal are provided becomes hot due to heat generated by an electric current during power supply or an arc during power off. Since the fixed yoke in the conventional electromagnetic relay disclosed in Patent Document 2 is located in the contact space, a contact point between the fixed yoke and the housing may become hot, and accordingly, bonding performance may be insufficient when bonding the fixed yoke and the housing with a bonding agent or adhesive tape.

[0013] Brazing or welding are accordingly selected as a method for bonding the fixed yoke and the housing, but in this case, positioning of the fixed yoke to the housing may not be easy.

[0014] A resin material used to secure insulation may also not be able to withstand the heat of brazing. PRIOR ART DOCUMENT PATENT DOCUMENT Patent Document 1: Japanese Patent No. 2010-10056 A Patent Document 2: Japanese Patent No. 2012-104356 A

[0015] Document US 2013 / 0 335 177 A1 discloses a contact device. An electromagnet device is configured to generate a magnetic attraction force between a stationary core and a movable core when electricity is applied to a coil, so that the movable core is moved in a direction to contact the stationary core, and a movable shaft is moved in a direction in which a first end surface of the movable shaft is separated from a movable terminal. After the movable contact comes into contact with the fixed contact, the movable core continues to move in a direction to contact the stationary core. A yoke made of a magnetic body is disposed between the movable terminal and the first end of the movable shaft.

[0016] Document US 9 564 279 B2 discloses an electromagnetic switch. The electromagnetic switch includes a pair of fixed contacts arranged and mounted in a contact housing with a predetermined distance therebetween, a movable contact arranged in the contact housing so as to contact or separate from the pair of fixed contacts, and an electromagnet unit that brings the movable contact into contact with the pair of fixed contacts or separates the movable contact therefrom.The electromagnet unit has a magnetic yoke enclosing an excitation coil, a movable plunger having a contact pole face facing the contact pole face of the magnetic yoke, and a connecting shaft connecting the movable plunger and the movable contact, and magnetic paths through which a holding force is generated by external magnetic fluxes generated by a flowing current when the movable contact touches the pair of fixed contacts are formed on the contact pole face of the magnetic yoke.

[0017] Document US 2014 / 0 015 627 A1 discloses a relay. The relay includes two stators, each having a fixed contact, and a movable element with movable contacts. Each of the stators includes a stator proximity plate portion adjacent to the movable element, and the movable element includes a moving element proximity plate portion adjacent to the stators. A current direction flowing in the stator proximity plate portions is set to coincide with a current direction flowing in the movable element proximity plate portion to generate an attractive force between the plates to attract the movable element proximity plate portion to the stator proximity plate portions. The movable element proximity plate portion is biased by the inter-plate attractive force in a direction to bring the movable contacts into contact with the fixed contacts. SUMMARY OF THE INVENTION

[0018] An object of the present disclosure is to provide a configuration of an electromagnetic relay in which contact separation caused by an electromagnetic contact point repulsion force is limited by a yoke attraction force generated between a movable yoke and a fixed yoke, the configuration capable of avoiding a lack of bonding between the fixed yoke and a fixed member. Another object is further to provide a configuration of the above-described electromagnetic relay capable of facilitating positioning of the fixed yoke on the fixed member or ensuring electrical insulation between a fixed terminal and the fixed yoke.

[0019] Furthermore, another object is to provide an electromagnetic relay in which flexibility in selecting a material of a base or flexibility in designing the base around the fixed yoke is increased.

[0020] These objects are achieved by the features of claim 1. Further advantageous embodiments and further developments are the subject of the subsequent claims.

[0021] An electromagnetic relay according to one aspect of the present disclosure includes an excitation coil that generates a magnetic field during energization, a movable core driven by the magnetic field generated by the excitation coil, a movable element having a movable contact and moving to follow the driven movable core, a plurality of fixed terminals, each of which has a fixed contact that contacts the movable contact during energization of the excitation coil, a base comprising an electrically insulating resin that holds the plurality of fixed terminals, a fixed yoke formed of a magnetic material and supported by at least one of the plurality of fixed terminals, and a movable yoke formed of a magnetic material and arrangedto face the fixed yoke, the movable yoke being in contact with the movable member and moving together with the movable member.

[0022] According to the above-described configuration, inadequacy of the bonding between the fixed yoke and a fixed member can be avoided in the electromagnetic relay in which contact separation caused by an electromagnetic contact point repulsion force is limited by a yoke attraction force generated between the movable yoke and the fixed yoke. Furthermore, in the above-described electromagnetic relay, positioning of the fixed yoke on the fixed member can be facilitated, and electrical insulation between the fixed terminal and the fixed yoke can be ensured.

[0023] Since the fixed yoke is supported by the fixed terminal, the fixed yoke is able to absorb heat generated in the fixed terminal. Accordingly, an increase in the temperature of the fixed terminal can be limited, and the heat-resistant property required for a resin material used as a base material can be reduced. Flexibility in selecting the base material can therefore be increased.

[0024] Furthermore, when the fixed yoke is supported by the fixed terminal, the fixed yoke does not need to be embedded in or fixed to the base, and accordingly, flexibility in designing the base around the fixed yoke is increased. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional diagram illustrating an electromagnetic relay in a state where an excitation coil is not energized according to a first embodiment of the present disclosure. Fig. 2 is a sectional diagram illustrating the electromagnetic relay in a state where the excitation coil is energized according to the first embodiment. Fig. 3 is an exploded view of the electromagnetic relay according to the first embodiment. Fig. 4A is a plan view illustrating a positional relationship between a movable yoke and fixed yokes of the electromagnetic relay according to the first embodiment. Fig. 4B is a plan view illustrating the movable yoke of the electromagnetic relay of the first embodiment. Fig. 4C is a plan view showing the fixed yoke of the electromagnetic relay of the first embodiment. Fig. 5 is a schematic sectional diagram showing a part of an electromagnetic relay according to a modification of the first embodiment. Fig. 6 is a sectional diagram illustrating an electromagnetic relay according to a second embodiment of the present disclosure. Fig. 7 is an exploded view of the electromagnetic relay according to the second embodiment. Fig. Figure 8 is a schematic sectional diagram showing a conventional electromagnetic relay. Fig. Figure 9 is a schematic sectional diagram showing the conventional electromagnetic relay in a state where an excitation coil is not energized. EXAMPLES OF USE OF THE INVENTION

[0025] The inventors of the present disclosure have already filed an application on a configuration capable of avoiding insufficiency of a binding force between a fixed yoke and a fixed member, facilitating positioning of the fixed yoke on the fixed member, or securing electrical insulation between a fixed terminal and the fixed yoke in an electromagnetic relay in which separation of contacts caused by an electromagnetic contact point repulsion force is limited by a yoke attraction force generated between a movable yoke and the fixed yoke (referring to JP 2013-056806 A).

[0026] Specifically, in order to limit the contact separation caused by the electromagnetic contact point repulsion force, the movable yoke is provided on one side of a movable element having a movable contact, and the fixed yoke is embedded in a base in which the fixed terminal having a fixed contact is held. According to this configuration, when an electric current flows in the movable element by connecting the movable contact and the fixed contact, a magnetic flux flows in the movable yoke and the fixed yoke, and accordingly, a yoke attraction force is generated between the movable yoke and the fixed yoke. Since the movable yoke urges the movable element toward the fixed terminal by the yoke attraction force, the contact separation caused by the electromagnetic contact point repulsion force is limited.

[0027] However, since the fixed terminal is heated and reaches a high temperature during power supply, it is necessary to select a resin material capable of withstanding the high temperature, and accordingly, flexibility in selecting a material for the base formed of resin that supports the fixed terminal may be reduced. In particular, since the electromagnetic relay described above has a configuration in which the fixed yoke is fixed by the base, it is necessary for the fixed yoke to be embedded in or bonded to the base. Accordingly, it is necessary to ensure the rigidity of the base, and flexibility in designing the base around the fixed yoke may be reduced.

[0028] Several embodiments for implementing the present invention are described below with reference to the drawings. In the respective embodiments, a part corresponding to a matter described in a previous embodiment may be assigned the same reference numeral, and redundant explanation of the part may be omitted. When only a part of a configuration is described in one embodiment, another previous embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided that the combination does not cause harm. (First embodiment)

[0029] A first embodiment of the present disclosure is described below. As in Fig. 1 to 4C, an excitation coil 12, which has a circular cylindrical shape and generates a magnetic field during energization, is arranged in a casing 11 made of resin. A fixed core 13, made of a magnetic metal material, is located in a hole provided in a radial direction at a central part of the excitation coil 12. The fixed core includes a core axis portion 131 having a circular columnar shape and inserted into the center hole of the excitation coil 12, and a core flange portion 132 positioned outside the excitation coil 12 and having a circular columnar shape whose diameter is larger than a diameter of the core axis portion 131.

[0030] An outer peripheral side and one end in an axial direction of the excitation coil 12 are surrounded by a second plate member 14, wherein the second plate member 14 is a plate member made of a magnetic metal material and bent into an approximately U-shape.

[0031] The other side of the excitation coil 12 in the axial direction is surrounded by a first plate member 15. The first plate member 15 has a rectangular plate shape and is made of a magnetic metal material. The first plate member 15 faces the movable core 16, which will be described below.

[0032] A yoke hole 151 extending through a central portion of the first plate member 15 is provided, and the core flange portion 132 is provided in the yoke hole 151. The fixed core 13 and the second plate member 14 are joined together, and the second plate member 14 and the first plate member 15 are joined together.

[0033] At a position facing the core flange portion 132 and the first plate member 15, the movable core 16, which has a plate shape and is made of a magnetic metal material, is provided. The fixed core 13, the second plate member 14, the first plate member 15, and the movable core 16 form a magnetic circuit of a magnetic flux induced by the excitation coil 12.

[0034] A return spring 17 is provided between the excitation coil 12 and the movable core 16, which urges the movable core 16 to move away from the fixed core 13. The movable core 16 is attracted by an electromagnetic attraction force against the urging force of the return spring 17 when the excitation coil 12 is energized.

[0035] A shaft 18 made of metal is fitted to the movable core 16. In more detail, the shaft 18 is inserted into a hole 161 of a movable plate provided in a central portion of the movable core 16, and a shaft flange portion 181 provided at one end of the shaft 18 and a first retaining ring 19 engaged with the shaft 18 cause the movable core 16 and the shaft 18 to be fitted together.

[0036] The movable core 16 and the shaft 18 are fitted together with a predetermined clearance to be able to move relatively in a radial direction and an axial direction of the shaft 18. Since the clearance is provided, the movable core 16 is able to securely contact the first plate member 15 and the core flange portion 132 when the movable core 16 is attracted toward the fixed core 13.

[0037] A central portion of the shaft 18 is slidably inserted into a base 20 made of an electrically insulating resin. A second retaining ring 21 is engaged with a portion of the shaft 18 that protrudes from the base 20. A movable member 22 made of a conductive metal and having a plate shape and a movable yoke 30 made of a magnetic metal material and having a plate shape are slidably attached to the portion of the shaft 18 that protrudes from the base 20.

[0038] Two movable contacts 25, made of a conductive metal, are hammered or forged onto the movable element 22 and fixed thereto. The movable yoke 30 contacts the movable element 22 and moves together with the movable element 22.

[0039] A pressure contact spring 24, which urges the movable member 22 and the movable yoke 30 toward the fixed core 13 (in other words, toward the retaining ring 21), is provided between a third retaining ring 23, which is engaged with the other end of the shaft 18, and the movable yoke 30.

[0040] It is preferable to place an electrically insulating object between the pressure contact spring 24 and the movable yoke 30. The pressure contact spring 24 can push the movable member 22 to which the movable yoke 30 is fixed.

[0041] A first fixed contact 27, made of a conductive metal, is hammered and fixed to a first fixed terminal 26, made of a conductive metal and having a plate shape. A second fixed contact 29, made of a conductive metal, is hammered and fixed to a second fixed terminal 28, made of a conductive metal and having a plate shape.

[0042] The first fixed contact 27 is positioned to face one movable contact 25, and the second fixed contact 29 is positioned to face the other movable contact 25.

[0043] The movable element 22 and the movable contact 25 move to follow the movable core 16. The movable contacts 25 accordingly come into and out of contact with the first fixed contact 27 and the second fixed contact 29, and thus the first fixed contact 27 and the second fixed contact 29 are electrically connected to or disconnected from each other.

[0044] A fixed yoke 31 is supported by and joined to the first fixed terminal 26 and the second fixed terminal 28, respectively. The fixed yokes 31 are plate members made of a magnetic metal and are supported by welding, bonding, hammering, or engaging the surfaces of the first fixed terminal 26 and the second fixed terminal 28, that is, a side opposite the movable member 22. The fixed yokes 31 may be directly supported by the first and second fixed terminals 26, 28.

[0045] The base 20 has a base plate portion 201 having a flat plate shape, a first holding plate portion 202 vertical to the base plate portion 201 into which the shaft 18 is inserted, and a second holding plate portion 203 extending along a direction in which the movable core 16 moves, as shown in Fig. 3. A groove 205, into which an edge portion of the second plate member 14 is inserted, is provided in the second holding plate portion 203.

[0046] The first fixed terminal 26 and the second fixed terminal 28 are held and fixed to a surface of the first holding plate portion 202, and the fixed yoke 31 is supported by the surface of the first holding plate portion 202. The fixed yoke 31 is embedded in the first holding plate portion 202 in the present embodiment, but the fixed yoke 31 does not necessarily have to be embedded in the first holding plate portion 202 because the fixed yoke 31 is held and fixed to the base 20 by fixing the first fixed terminal 26 and the second fixed terminal 28. The fixed terminals 26, 28 may be provided between the movable core 16 and the movable member 22.

[0047] The edge portion of the second plate member 14 is press-fitted into and fixed to the groove 205, and accordingly, the second plate member 14 is integrally attached to the base 20.

[0048] The movable yoke 30 and the fixed yoke 31 will be described in detail next. When the excitation coil 12 is energized, the movable core 16 is attracted to the fixed core 13 by an electromagnetic attraction force, and the movable element 22 follows the movable core 16 and moves in a direction indicated by an arrow A. In the following description, the direction A in which the movable element 22 moves when the excitation coil 12 is energized is referred to as a contact movement direction A. A direction opposite to the contact movement direction A is referred to as a separation movement direction.

[0049] The fixed yoke 31 is configured from a plate member having a cuboid shape, for example, a first fixed yoke 31A is supported by the first fixed terminal 26, and a second fixed yoke 31B is supported by the second fixed terminal 28. The first and second fixed yokes 31A, 31B are spaced apart from each other by a predetermined distance, and the shaft 18 is inserted therebetween. In the present embodiment, the first and second fixed yokes 31A, 31B have the same size, but they do not necessarily have to be the same size. When both the first fixed terminal 26 and the second fixed terminal 28 are provided, the first and second fixed yokes 31A, 31B may be provided for each fixed terminal, respectively.

[0050] The fixed yoke 31 is positioned on one side of the contact moving direction A of the movable member 22, and at least a part of the fixed yoke 31 projects into a space between the first fixed terminal 26 and the second fixed terminal 28 when viewed along the contact moving direction A.

[0051] The movable yoke 30 is a plate member having, for example, a cuboid shape, and a through hole 301 into which the shaft 18 is inserted is provided in a central part of the movable yoke 30. The movable yoke 30 is positioned on one side of the movable member 22 of the fixed yoke 31, and more specifically, the movable yoke 30 is positioned on a side of the movable member 22 facing away from the fixed yoke 31 (in other words, on a side of the separation movement direction).

[0052] As in Fig. 4A, the movable yoke 30 and the fixed yoke 31 are arranged to overlap (in other words, face) each other when viewed along the contact moving direction A.

[0053] Operations of the electromagnetic relay according to the present embodiment will be described next.

[0054] When the excitation coil 12 is first energized, the movable core 16 is attracted by the electromagnetic attraction force against the return spring 17 toward the fixed core 13, and the shaft 18 and the movable member 22 follow the movable core 16 and move in the contact moving direction A. Accordingly, the movable contact 25 comes into contact with the first fixed contact 27 and the second fixed contact 29, and the first fixed contact 27 and the second fixed contact 29 are electrically connected to each other (refer to Fig. 2).

[0055] Since an electric current caused by the connection between the first fixed contact 27 and the second fixed contact 29 flows in the movable element 22, a magnetic flux flows in the movable yoke 30 and the fixed yoke 31, and accordingly, a yoke attraction force is generated between the movable yoke 30 and the fixed yoke 31. The movable yoke 30 urges the movable element 22 toward the first fixed terminal 26 and the second fixed terminal 28 by the yoke attraction force. Therefore, a breaking contact caused by an electromagnetic contact point repulsion force is limited by the yoke attraction force.

[0056] Since the fixed yoke 31 is not fixed to the shaft 18 and is immobile, the shaft 18, the movable element 22, and the movable core 16 are not urged in the separation direction by the fixed yoke 31. Accordingly, a reduction in the electromagnetic attraction force caused by a movement of the movable core 16 in a direction away from the fixed core 13 is limited. Therefore, the electromagnetic attraction force does not need to be increased by using a large excitation coil 12.

[0057] On the other hand, when the supply of energy to the excitation coil 12 is stopped, the movable core 16, the shaft 18, and the movable element 22 are driven in the separation movement direction by the return spring 17. The movable contact 25 is therefore separated from the first fixed contact 27 and the second fixed contact 29, and the first fixed contact 27 and the second fixed contact 29 are electrically separated (refer to Fig. 1).

[0058] Since the yoke attraction force acts against the return spring 17, the yoke attraction force affects a characteristic of the electromagnetic relay when the electric current is stopped. Therefore, it is preferable that the yoke attraction force when the electric current is stopped be sufficiently smaller than a spring force of the return spring 17.

[0059] According to the present embodiment, even if a large amount of electric current flows at a short circuit, separation of contacts caused by an electromagnetic contact point repulsion force can be surely limited without increasing the size of the excitation coil 12.

[0060] Since the fixed yoke 31 is supported by the first fixed terminal 26 and the second fixed terminal 28, a heat capacity of the fixed yoke 31 can be added to a heat capacity of the first fixed terminal 26 and the second fixed terminal 28 when they generate heat. Therefore, an increase in temperature of the first fixed terminal 26 and the second fixed terminal 28 can be limited, and accordingly, a heat-resistant property required for a resin material that is a material of the base 20 can be relaxed. Therefore, flexibility in selecting the material of the base 20 can be increased.

[0061] In addition, since the fixed yoke 31 is supported by the first fixed terminal 26 and the second fixed terminal 28, the fixed yoke 31 does not need to be embedded in or bonded to the base, and accordingly, flexibility in designing the base around the fixed yoke 31 can be increased.

[0062] Since the yoke attraction force is generated in a vicinity of an area where an electromagnetic contact point repulsion force is generated, separation of contacts caused by an electromagnetic contact point repulsion force can be securely limited even if a spring load is not evenly applied to both contacts.

[0063] Furthermore, since the fixed yoke 31 is positioned in an unused space between the first fixed terminal 26 and the second fixed terminal 28, the electromagnetic relay can be downsized.

[0064] When the fixed yoke 31 is disposed within the base 20 made of an electrically insulating resin, an electrically insulating state can be secured between the first fixed terminal 26 and the fixed yoke 31, and between the second fixed terminal 28 and the fixed yoke 31. Furthermore, a facing area where the fixed yoke 31 and the movable yoke 30 face each other can also be increased, and the yoke attraction force can be increased, and accordingly, contact separation caused by an electromagnetic contact point repulsion force can be further securely limited.

[0065] The movable yoke 30 and the fixed yoke 31 can be used as a modification described in Fig. 5, for example, be modified.

[0066] The modification, which is Fig. 5, the movable yoke 30 is positioned on one side of the fixed yoke 31 (in other words, one side of the contact movement direction A) of the movable member 22. In this case, the movable yoke 30 is joined to the movable member 22 by bonding, hammering, or the like.

[0067] Since the fixed yoke 31 and the movable yoke 30 are close to each other to increase the yoke attraction force, separation of the contacts caused by an electromagnetic contact point repulsion force can be securely limited. (Second embodiment)

[0068] A second embodiment of the present disclosure will be described below. In this embodiment, the configurations of a first fixed contact 27 and a fixed yoke 31 are changed from the first embodiment, and the other configurations are the same as those in the first embodiment. Accordingly, only parts different from the first embodiment will be described below.

[0069] As in Fig. 6, in the present embodiment, the fixed yoke 31 supported by a second fixed terminal 28, which is provided in the first embodiment, is not provided, and only the fixed yoke 31 supported by a first fixed terminal 26 is provided. Since a cross section shown in Fig. 6 is a cross-section showing a through-hole 301 into which a shaft 18 is inserted, the fixed yoke 31 is separated. However, in another cross-section, the fixed yoke 31 is continuous. Since the fixed yoke 31 is provided on only one side of two fixed terminals and faces a movable yoke 30 on both sides of the shaft 18, a yoke attraction force generated is balanced.

[0070] As in Fig. As shown in Fig. 7, two second fixed contacts 29 are provided in the second fixed terminal 28, and a first fixed contact 27 is provided in the first fixed terminal 26. An electromagnetic relay according to the present embodiment is configured from the configuration described above.

[0071] When the first and second fixed terminals 26, 28 are heated during power supply, an electric current is concentrated at the terminal having a smaller number of fixed contacts, and accordingly, the first fixed terminal 26, which has only one first fixed contact 27, is likely to have a high temperature compared to the second fixed terminal 28, which has two second fixed contacts 29. Accordingly, in the present embodiment, since the fixed yoke 31 is provided only on the side of the first fixed terminal 26, which is likely to have a high temperature, an increase in a temperature of the first fixed terminal 26 can be limited by increasing a heat capacity.

[0072] Accordingly, the same effects as in the first embodiment can be obtained from the configuration in which the fixed yoke 31 is provided only in one of the first and second fixed terminals 26, 28. Since the fixed yoke 31 is provided only on the side of the first fixed terminal 26, the number of components can be reduced.

[0073] The present disclosure is not limited to the embodiments described above and may be modified as described below as long as it does not deviate from the spirit of the present disclosure.

[0074] In the above-described embodiment, the first fixed contact 27 is hammered onto the first fixed terminal 26, which is a different component from the first fixed contact 27, and the second fixed contact 29 is hammered onto the second fixed terminal 28, which is a different component. However, a protruding portion protruding toward the movable member 22 may be provided by stamping, and the protruding portion may be used as the fixed contact. The fixed contacts 27, 29 may be seamlessly formed integrally with the fixed terminals 26, 28.

[0075] In the above-described embodiment, the movable contact 25 is hammered onto the movable member 22, which is a different component from the movable contact 25. However, a protruding portion projecting toward the first fixed terminal 26 and the second fixed terminal 28 may be provided by stamping, and the protruding portion may be used as the movable contact. The movable contact 25 may be seamlessly formed integrally with the movable member.

[0076] In the first embodiment, the movable yoke 30 is provided as a single component having the through-hole 301 in the central part thereof, but the movable yoke 30 may be provided as two components arranged to face the first and second fixed contacts 27, 29, respectively.

[0077] The present disclosure is not limited to the embodiments described above and may be modified as desired.

[0078] In the embodiments described above, it is needless to say that the components of the embodiments are not essential, except in a case where a component is obviously essential in principle or it is explicitly described that it is essential.

[0079] In the embodiments described above, when a number, a numerical value, a quantity, numerical ranges, etc. of components are mentioned, these should not be limited to the specific number, except in a case where the component is obviously limited to the specific number in principle, or it is explicitly described that this is essential.

[0080] Although the present disclosure is described in connection with exemplary embodiments, the present disclosure is not limited to the exemplary embodiments of their configurations. The present disclosure encompasses various modifications or changes within their equivalents. Furthermore, various combinations of embodiments are possible.

Claims

[1] Electromagnetic relay with: an excitation coil (12) which generates a magnetic field during a supply of energy; a movable core (16) driven by the magnetic field generated by the excitation coil (12); a movable member (22) having a movable contact (25) and moving to follow the driven movable core (16); a plurality of fixed terminals (26, 28), each having a fixed contact (27, 29) that contacts the movable contact (25) during the supply of energy to the excitation coil (12); a base (20) comprising an electrically insulating resin that holds the plurality of fixed terminals (26, 28); a fixed yoke (31, 31A, 31B) formed of a magnetic material and supported by at least one of the plurality of fixed terminals (26, 28); and a movable yoke (30, 30A, 30B) formed of a magnetic material and arranged to face the fixed yoke (31, 31A, 31B), the movable yoke (30, 30A, 30B) being in contact with the movable element (22) and moving together with the movable element (22), a direction in which the movable element (22) moves during the supply of energy to the excitation coil (12) is a contact movement direction (A); and a part of the fixed yoke (31, 31A, 31B) projects into a space between the plurality of fixed terminals (26, 28) when the fixed yoke (31, 31A, 31B) is viewed along the contact movement direction (A); and wherein the fixed yoke (31, 31A, 31B) has a plate shape and the fixed terminal (26, 28) is between the movable element (22) and the fixed yoke (31, 31A, 31B) in the contact movement direction (A). [2] Electromagnetic relay according to claim 1, wherein the plurality of fixed terminals (26, 28) comprises a first fixed terminal (26) and a second fixed terminal (28); the fixed yoke (31, 31A, 31B) comprises a first fixed yoke (31A) and a second fixed yoke (31B); the first fixed yoke (31A) is supported by the first fixed terminal (26); and the second fixed yoke (31B) is supported by the second fixed terminal (28). [3] An electromagnetic relay according to claim 1, wherein the plurality of fixed terminals (26, 28) comprises a first fixed terminal (26) and a second fixed terminal (28); the fixed contact (27) of the first fixed terminal (26) is a single first fixed contact (27); the fixed contacts (29) of the second fixed terminal (28) are two second fixed contacts (29); and the fixed yoke (31) is supported by the first fixed connection (26). [4] Electromagnetic relay according to one of claims 1 to 3, wherein the fixed contact (27, 29) is integral with the plurality of fixed terminals (26, 28). [5] Electromagnetic relay according to one of claims 1 to 4, wherein the fixed terminal (26, 28) is located between the movable core (16) and the movable element (22).

Images