Electromagnet device, electromagnet system, and electromagnetic relay

Abstract

An electromagnetic relay (1) comprises a contact part (2) and an electromagnet part (3). The electromagnet part (3) is an electromagnet device. In an off state of the electromagnet part (3), a movable element core (33) is at the illustrated base position. In an on state, the electromagnet part (3) moves the movable element core (33) in a first direction (AD1). The electromagnetic relay (1) has a magnetic bias device (8). The magnetic bias device (8) attracts the movable element core (33) in a second direction (AD2) with the magnetic force of a permanent magnet (81). The magnetic bias device (8) applies a biasing force to the movable element core (33) most strongly at the base position of the movable element core (33). However, as the movable element core (33) moves in the first direction AD1, the biasing force is rapidly lost. The magnetic bias device (8) suppresses incorrect behavior in an off state.

Description

Electromagnetic device, electromagnetic system, and electromagnetic relay CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-152490 filed in Japan on September 4, 2024, and the contents of the original application are incorporated by reference in their entirety.

[0002] The disclosure herein relates to an electromagnetic device and an electromagnetic relay.

[0003] Patent Document 1 discloses an electromagnet device having a permanent magnet in a magnetic circuit, and an electromagnetic relay. The permanent magnet in Patent Document 1 supplies magnetic flux in a predetermined direction to a gap between a stator and a mover. This predetermined direction is the same direction (forward direction) as the magnetic flux supplied to the gap by an excitation coil. The contents of the prior art documents are incorporated by reference as explanations of the technical elements in this specification.

[0004] Japanese Patent Application Laid-Open No. 2020-87567

[0005] It is necessary to prevent false ON behavior in an OFF state in an electromagnetic device and an electromagnetic relay. The permanent magnet in Patent Document 1 biases the mover in the ON direction. In other words, the permanent magnet in Patent Document 1 does not suppress false ON behavior. In the above-mentioned respects and in other respects not mentioned, further improvements are required in an electromagnetic device and an electromagnetic relay.

[0006] One disclosed object is to provide an electromagnetic device and an electromagnetic relay that are suppressed from erroneous behavior in the off state.

[0007] The electromagnetic device disclosed herein comprises an electromagnetic coil that can be switched between an on state and an off state of the excitation current, a fixed magnetic body that is disposed in a magnetic field induced by the electromagnetic coil and is fixedly disposed, a movable magnetic body that is disposed in the magnetic field induced by the electromagnetic coil and is movable in a first direction approaching the fixed magnetic body and in a second direction opposite to the first direction, and that is at a base position in the second direction when the excitation current is off and moves from the base position toward the first direction when the excitation current is on, and a magnetic bias device that supplies a magnetic flux that attracts the movable magnetic body in the second direction.

[0008] In the disclosed electromagnet device, the movable magnetic mass is attracted in the second direction by the magnetic bias device, so that the movable magnetic mass is held in the base position by the magnetic bias device while the electromagnetic coil is in the off state, thereby suppressing erroneous behavior in the off state.

[0009] The electromagnetic relay disclosed therein comprises the above-mentioned electromagnet device and a contact portion that is switched between an ON state and an OFF state by the movement of the movable magnetic body.

[0010] In the disclosed electromagnetic relay, the movable magnetic mass is held in the base position by the magnetic bias device while the electromagnetic coil is in the OFF state, thereby suppressing erroneous behavior of the electromagnetic relay when the electromagnetic coil is in the OFF state.

[0011] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify the correspondence with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings.

[0012] FIG. 1 is a cross-sectional view of an electromagnetic relay according to a first embodiment. FIG. 2 is an exploded perspective view showing a magnetic bias device. FIG. 3 is a partial cross-sectional view showing magnetic flux in an off state. FIG. 4 is a partial cross-sectional view showing magnetic flux in an on state. FIG. 1 is a cross-sectional view of an electromagnetic relay according to a second embodiment. FIG. 2 is an exploded perspective view showing a magnetic bias device. FIG. 3 is a cross-sectional view of an electromagnetic relay according to a third embodiment. FIG. 4 is a cross-sectional view of an electromagnetic relay according to a fourth embodiment. FIG. 5 is a cross-sectional view of an electromagnetic relay according to a fifth embodiment. FIG. 6 is a block diagram of a control system. FIG. 7 is a cross-sectional view showing multiple energization modes of an electromagnetic relay. FIG. 8 is a flowchart for controlling an electromagnetic relay. FIG. 9 is a waveform diagram showing transitions in the energization state of an electromagnetic relay. FIG. 10 is a cross-sectional view of an electromagnetic relay according to an eighth embodiment. FIG. 11 is a cross-sectional view of an electromagnetic relay according to a ninth embodiment. FIG. 11 is a cross-sectional view of an electromagnetic relay according to a tenth embodiment. FIG. 12 is a cross-sectional view of an electromagnetic relay according to an eleventh embodiment.

[0013] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digits. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0014] In the first embodiment shown in FIG. 1, an electromagnetic relay 1 includes a contact portion 2 and an electromagnetic portion 3. The contact portion 2 and the electromagnetic portion 3 are arranged in a layered configuration in the axial direction. In this embodiment, the direction of movement of a movable contact by the electromagnetic portion 3 is defined as the axial direction. The contact portion 2 is also called a contact unit or a contact module. The electromagnetic portion 3 is also called an electromagnet device, an electromagnetic unit, or an electromagnetic actuator.

[0015] The contact portion 2 and the electromagnetic portion 3 are operatively connected by a shaft 4. The shaft 4 transmits the motion of the electromagnetic portion 3 to the contact portion 2. The shaft 4 provides a mechanical linkage member.

[0016] The contact unit 2 and the electromagnetic unit 3 are accommodated in a housing 10. The housing 10 is provided by an upper case 11 and a lower case 12. The housing 10 has a pair of fixed contacts 21, 22. A portion of the pair of fixed contacts 21, 22 is exposed to the outside of the housing 10. The pair of fixed contacts 21, 22 are connected to the power line that is connected and disconnected by the contact unit 2. The pair of fixed contacts 21, 22 are also called a pair of power terminals. Furthermore, the housing 10 has a pair of control terminals for supplying electricity to the electromagnetic unit 3. The pair of control terminals are not shown in the figure.

[0017] The contact portion 2 includes a pair of fixed contacts 21, 22 and a movable contact 23. The pair of fixed contacts 21, 22 are arranged side by side so as to extend parallel to each other. The direction in which the pair of fixed contacts 21, 22 are arranged, i.e., the left-right direction in FIG. 1 , is also called the width direction of the electromagnetic relay 1.

[0018] The movable contactor 23 extends over a range that includes the pair of fixed contactors 21, 22. The movable contactor 23 extends over a range that faces both of the pair of fixed contactors 21, 22. The movable contactor 23 is a rectangular conductive member. The movable contactor 23 is movable between a state in contact with the pair of fixed contactors 21, 22 and a state away from the pair of fixed contactors 21, 22.

[0019] The movable contact 23 switches between an electrically connected state and an electrically disconnected state between the pair of fixed contacts 21, 22. The movable contact 23 can switch between an ON state in which the pair of fixed contacts 21, 22 are electrically connected, and an OFF state in which the pair of fixed contacts 21, 22 are electrically disconnected. Thus, the movable contact 23 electrically connects and disconnects the pair of fixed contacts 21, 22. The movable contact 23 is operatively connected to the shaft 4 so as to move in conjunction with the movement of the shaft 4.

[0020] The on and off states provided by the pair of fixed contacts 21, 22 and the movable contact 23 are called the on and off states of the contact unit 2. On the other hand, the on and off states of the electromagnetic unit 3 are provided by the on and off states of current flow to the electromagnetic coil 31, which will be described later. In this embodiment, the on state of the contact unit 2 corresponds to the on state of the electromagnetic unit 3, and the off state of the contact unit 2 corresponds to the off state of the electromagnetic unit 3. Instead of this embodiment, an alternative configuration can be adopted in which the on state of the contact unit 2 corresponds to the off state of the electromagnetic unit 3, and the off state of the contact unit 2 corresponds to the on state of the electromagnetic unit 3. Those skilled in the art who have access to the disclosure in this specification should understand that such alternative configurations are included.

[0021] A movable coupling mechanism is provided between the movable contactor 23 and the shaft 4 to allow adjustable movement of the movable contactor 23. In this embodiment, the movable coupling mechanism is provided by a support member 24 and a bias spring 25. The support member 24 is fixedly supported with respect to the shaft 4. The bias spring 25 is a coil spring. The bias spring 25 is arranged in a compressed state between the support member 24 and the movable contactor 23. The support member 24 and the bias spring 25 allow adjustable movement of the movable contactor 23. The adjustable movement includes axial movement of the movable contactor 23 relative to the shaft 4 and swinging of the movable contactor 23 relative to the shaft 4. As a result, stable contact is achieved between the pair of fixed contactors 21, 22 and the movable contactor 23. The movable coupling mechanism is not limited to the example shown in this embodiment.

[0022] The contact unit 2 is switched between an ON state and an OFF state by movement of a movable core 33, which will be described later. In this embodiment, the contact unit 2 includes a pair of fixed contacts 21, 22, but the contact unit 2 may also be provided by a single-throw switch having only a single fixed contact.

[0023] The electromagnetic unit 3 includes an electromagnetic coil 31, a stator core 32, a mover core 33, a yoke 34, and a bias spring 35. The electromagnetic unit 3 generates axial motion by turning on and off an electromagnetic force. The electromagnetic unit 3 generates motion in a first axial direction AD1 and a second axial direction AD2. The first direction AD1 and the second direction AD2 are opposite directions.

[0024] The electromagnetic coil 31 is switched between an on state and an off state of the excitation current. The electromagnetic coil 31 excites the stator core 32 and the mover core 33. The electromagnetic coil 31 includes a bobbin 31a made of an insulating material and a coil 31b wound around the bobbin 31a. The stator core 32, the mover core 33, and the yoke 34 are made of a magnetic material with soft magnetic properties. The stator core 32, the mover core 33, and the yoke 34 are made of metal, for example, iron.

[0025] The stator core 32 is disposed in a magnetic field induced by the electromagnetic coil 31. The stator core 32 is fixedly disposed in the electromagnetic unit 3. The stator core 32 is fixedly supported relative to the yoke 34. The stator core 32 is fixed so that magnetic flux passes between the stator core 32 and the yoke 34. The stator core 32 is also referred to as a fixed magnetic body or a stator. The stator core 32 in this embodiment has a shape that can be called a columnar or cylindrical. Alternatively, the stator core 32 may be provided in a shape that can be called a plate, a prismatic column, a square tube, or the like.

[0026] The mover core 33 is disposed in a magnetic field induced by the electromagnetic coil 31. The mover core 33 is supported in the electromagnetic unit 3 so as to be movable in the axial direction relative to the stator core 32. The mover core 33 is disposed so as to be movable in a first direction AD1 approaching the stator core 32 and a second direction AD2 opposite to the first direction AD1. The mover core 33 is movable in both the first direction AD1 and the second direction AD2. The mover core 33 is fixed to the shaft 4. The shaft 4 mechanically connects the mover core 33 and the movable contact 23. The stator core 32 and the mover core 33 are disposed opposite each other in the movement direction of the shaft 4. The movement direction of the shaft 4 is also referred to as the axial direction of the electromagnetic relay 1. The mover core 33 is also referred to as a movable magnetic body or a mover. In this embodiment, the mover core 33 has a shape that can be called a cylindrical or cylindrical shape. Alternatively to this embodiment, the mover core 33 may be provided in a shape that can be called a plate-like, prismatic, or rectangular tube-like shape.

[0027] 1 is a state in which the mover core 33 is located at the base position. The base position of the mover core 33 corresponds to the OFF state of the contact unit 2. The base position of the mover core 33 corresponds to the OFF state of the electromagnetic unit 3. Therefore, when the excitation current is OFF, the mover core 33 is located at the base position in the second direction AD2, and when the excitation current is ON, the mover core 33 moves from the base position toward the first direction AD1.

[0028] The bias spring 35 is a coil spring. The bias spring 35 is disposed in a compressed state between the stator core 32 and the mover core 33. The bias spring 35 applies a force to the stator core 32 and the mover core 33 in a direction that moves the mover core 33 away from the stator core 32. The direction in which the mover core 33 approaches the stator core 32 is a first direction AD1. The direction in which the mover core 33 moves away from the stator core 32 is a second direction AD2 opposite to the first direction AD1. The bias spring 35 applies a bias force that urges the mover core 33 in the second direction AD2. The force that moves the mover core 33 away in the second direction AD2 is also called a bias force, a spring bias force, or a mechanical bias force. The bias spring 35 applies a stable bias force equal to or greater than a predetermined value throughout the entire movable range of the mover core 33.

[0029] The yoke 34 is a member that provides a magnetic circuit. The yoke 34 is also called a first yoke. The yoke 34 provides an electromagnetic coupling member that supplies the magnetic flux generated by the electromagnetic coil 31 to the stator core 32 and the mover core 33. The yoke 34 forms a magnetic circuit for passing the magnetic flux induced by the electromagnetic coil 31. The yoke 34 includes a plurality of members that form the magnetic circuit. The yoke 34 includes a plate member 36, a back yoke member 37, and a magnetic flux guide member 38.

[0030] The plate member 36 is disposed between the contact portion 2 and the electromagnetic portion 3. The stator core 32 is fixed to the plate member 36. The plate member 36 extends into a plate shape on the contact portion 2 side of the electromagnetic portion 3 or the electromagnetic coil 31. The plate member 36 is fixedly connected to the stator core 32 at its radially inner end. The plate member 36 is a member that provides a reference for the position of the stator core 32. The plate member 36 is fixedly connected to a back yoke member 37 at its radially outer end.

[0031] The back yoke member 37 extends between the plate member 36 and the magnetic flux guide member 38 outside the electromagnetic coil 31 .

[0032] The magnetic flux guide member 38 is a cylindrical member. The magnetic flux guide member 38 is arranged radially outside the mover core 33. The mover core 33 and the magnetic flux guide member 38 face each other in the radial direction. The magnetic flux guide member 38 provides a path for magnetic flux by the radially facing relationship between the mover core 33 and the magnetic flux guide member 38. This facing relationship provides a necessary relationship, for example, an axial length, throughout the entire movable range of the mover core 33. The magnetic flux guide member 38 is a cylindrical member arranged radially outside the mover core 33 along the movement direction of the mover core 33.

[0033] In this embodiment, the back yoke member 37 and the magnetic flux guide member 38 are provided by separate members that are not made of continuous material. Alternatively, the back yoke member 37 and the magnetic flux guide member 38 may be provided by an integral member that is made of continuous material.

[0034] When the electromagnetic coil 31 is allowed to be energized and the magnetic circuit is excited, the mover core 33 is attracted toward the stator core 32 against the bias spring 35. As a result, the gap between the stator core 32 and the mover core 33 decreases. The mover core 33 drives the shaft 4 in the axial direction, i.e., upward in the figure. When the electromagnetic coil 31 is deenergized and the magnetic circuit is de-energized, the mover core 33 is pushed by the bias spring 35 in a direction away from the stator core 32. As a result, the gap between the stator core 32 and the mover core 33 increases. The mover core 33 drives the shaft 4 in the axial direction, i.e., downward in the figure.

[0035] The electromagnetic relay 1 includes a partition member 6 that partitions the arc-extinguishing chamber 5. The arc-extinguishing chamber 5 is formed across the contact unit 2 and the electromagnetic unit 3. The arc-extinguishing chamber 5 is a chamber filled with gas for extinguishing an arc that occurs at the contact unit 2. The partition member 6 includes some components of the contact unit 2 and some components of the electromagnetic unit 3. The arc-extinguishing chamber 5 houses movable members of the electromagnetic relay 1. In this embodiment, the movable members of the electromagnetic relay 1 include at least the shaft 4, the movable contact 23, the support member 24, the bias spring 25, the movable contact core 33, and the bias spring 35. The arc-extinguishing chamber 5 houses a pair of fixed contacts 21, 22 and the movable contact 23.

[0036] The partition member 6 includes a capsule member 61. The capsule member 61 supports a pair of fixed contacts 21, 22. The capsule member 61 is a member made of ceramics. The capsule member 61 is a cylindrical body with a closed bottom, and has a pair of fixed contacts 21, 22 at the bottom. The pair of fixed contacts 21, 22 are fixed airtight to the capsule member 61. The pair of fixed contacts 21, 22 and the capsule member 61 are connected by a joint made by brazing or welding.

[0037] The partition member 6 includes a flange member 62. The flange member 62 is a metal plate-like member. The flange member 62 has a cylindrical portion extending along the axial direction and a flange portion that annularly expands radially outward from the tip of the cylindrical portion. The flange member 62 is airtightly fixed to the opening of the capsule member 61 at its base end. The flange portion of the flange member 62, which is the other end, is airtightly fixed to the plate member 36. The flange portion of the flange member 62 is airtightly fixed to the edge plate portion 41 of the plate member 36. The airtight fixation is provided by a joint formed by brazing or welding.

[0038] In this embodiment, the plate member 36 of the electromagnetic section 3 is also part of the partition member 6. The plate member 36 is hermetically fixed to the stator core 32. The hermetically fixed joint is provided by brazing or welding, for example, by laser welding.

[0039] The partition member 6 includes a sleeve 63. The sleeve 63 is a cylindrical member with an open end and a bottom. The sleeve 63 is made of a material that transmits magnetic flux. The sleeve 63 is made of stainless steel, for example. The sleeve 63 is arranged with the stator core 32 positioned at the open end. The sleeve 63 is hermetically fixed to the stator core 32. Again, the hermetic fixation is provided by a joint formed by brazing or welding, for example, laser welding.

[0040] The sleeve 63 movably accommodates the mover core 33. The sleeve 63 is disposed radially inside the magnetic flux guide member 38. The sleeve 63 positions the mover core 33 on the radial inside and the magnetic flux guide member 38 on the radial outside. The sleeve 63 is disposed between the mover core 33 and the magnetic flux guide member 38.

[0041] As a result, the arc-extinguishing chamber 5 is defined by the capsule member 61, the flange member 62, the plate member 36, the stator core 32, and the sleeve 63. The sleeve 63 may be airtightly fixed to the plate member 36. In this case, the arc-extinguishing chamber 5 is defined by the capsule member 61, the flange member 62, the plate member 36, and the sleeve 63.

[0042] When current is allowed to flow through the electromagnetic coil 31 and the magnetic circuit is excited, magnetic flux passes through the variable gap between the stator core 32 and the mover core 33. The magnetic flux then passes through the yoke 34. The magnetic flux then passes through the sleeve 63 between the mover core 33 and the magnetic flux guide member 38. Most of the magnetic flux components pass through the sleeve 63 in the radial direction. The magnetic flux can pass through the sleeve 63 throughout the entire movable range of the mover core 33.

[0043] The electromagnetic relay 1 includes a permanent magnet 7 for driving an arc. The permanent magnet 7 supplies a drive magnetic field that extends the arc within the arc-extinguishing chamber 5. The drive magnetic field extends the arc within the arc-extinguishing chamber 5. The permanent magnet 7 includes a first magnet 71 and a second magnet 72. The drive magnetic field provided by the first magnet 71 axially extends the first arc generated between the fixed contact 21 and the movable contact 23, thereby extinguishing the arc. The drive magnetic field provided by the second magnet 72 axially extends the second arc generated between the fixed contact 22 and the movable contact 23, thereby extinguishing the arc.

[0044] The electromagnetic relay 1 has a magnetic bias device 8. The magnetic bias device 8 applies a bias force to the mover core 33. The bias force in this embodiment urges the mover core 33 toward the OFF state of the contact unit 2. In other words, the bias force in this embodiment urges the mover core 33 toward the OFF state of the electromagnetic unit 3. The bias force in this embodiment attracts the mover core 33 toward the OFF state of the contact unit 2. In other words, the bias force in this embodiment attracts the mover core 33 toward the OFF state of the electromagnetic unit 3. Instead of this embodiment, an alternative configuration can be adopted that applies a bias force that urges the mover core 33 toward the ON state of the contact unit 2.

[0045] The magnetic bias device 8 is disposed at an end of the mover core 33 in the movement direction. The magnetic bias device 8 is disposed opposite an end of the mover core 33 in the second direction AD2. The movement direction of the mover core 33 is the axial direction of the mover core 33. Both ends of the mover core 33 in the movement direction include one end facing the stator core 32 and the other end facing the magnetic bias device 8. In other words, the magnetic bias device 8 is disposed at the other end of the mover core 33 located opposite to one end of the mover core 33 where the stator core 32 and the mover core 33 face each other. The stator core 32 is disposed at one end of the mover core 33 in the movement direction of the mover core 33 via a gap. The magnetic bias device 8 is disposed at the other end of the mover core 33 in the movement direction of the mover core 33. Of the two ends of the mover core 33, the end facing the stator core 32 is also called the inner end. Of the two ends of the mover core 33, the end facing the magnetic bias device 8 is also called the outer end. In other words, the stator core 32 is disposed opposite the inner end of the mover core 33. The magnetic bias device 8 is disposed opposite the outer end of the mover core 33.

[0046] The magnetic bias device 8 is disposed opposite the other end of the mover core 33 in the direction of movement. This allows the magnetic bias device 8 to supply a magnetic flux that attracts the mover core 33 in the second direction AD2. In other words, the magnetic bias device 8 applies a bias force that attracts the mover core 33 in the second direction AD2 from the other end of the mover core 33 in the direction of movement. As a result, when the mover core 33 moves in the first direction AD1 and the distance between the mover core 33 and the magnetic bias device 8 increases, the bias force in the second direction AD2 rapidly decreases as the distance increases. In other words, when the mover core 33 moves in the first direction AD1, the bias force provided by the magnetic bias device 8 rapidly decreases. That is, the magnetic bias force applied by the magnetic bias device 8 is strongest at the base position of the mover core 33 and rapidly weakens as the mover core 33 moves from the base position in the first direction AD1.

[0047] The stator core 32 and the mover core 33 are arranged so that the mover core 33 is attracted toward the stator core 32 when excited by the electromagnetic coil 31. The direction in which the mover core 33 faces the stator core 32 is a first direction AD1. The mover core 33 and the magnetic bias device 8 are arranged so that the mover core 33 is attracted toward a second direction AD2 opposite to the first direction AD1. The magnetic force that attracts the mover core 33 in the second direction AD2 is also called a bias force or a magnetic bias force.

[0048] The magnetic bias device 8 has a permanent magnet 81 and a yoke 82. The permanent magnet 81 imparts a magnetic force to the mover core 33. The permanent magnet 81 is a magnetic force source that applies a magnetic bias force to the mover core 33. The permanent magnet 81 supplies a magnetic flux that attracts the mover core 33 in a direction that pulls it away from the stator core 32. The yoke 82 guides the magnetic flux of the permanent magnet 81. The yoke 82 forms a magnetic circuit for supplying the magnetic flux of the permanent magnet 81 to the mover core 33. The yoke 82 is also called a second yoke. In the electromagnetic unit 3, the magnetic circuit using the electromagnetic coil 31 as a magnetic force source is also called a main magnetic circuit or a basic magnetic circuit. In the electromagnetic unit 3, the magnetic circuit using the permanent magnet 81 as a magnetic force source is also called a secondary magnetic circuit or an additional magnetic circuit.

[0049] The yoke 82 has a plate-shaped bottom wall 83 and a plate-shaped cylindrical wall 84. The bottom wall 83 and the cylindrical wall 84 are provided by a continuous material. The bottom wall 83 is positioned opposite the lower surface of the permanent magnet 81. The cylindrical wall 84 is disposed inside the magnetic flux guide member 38. The cylindrical wall 84 is disposed such that its annular end face faces the bottom of the sleeve 63. The cylindrical wall 84 is disposed such that its radially outer surface faces the radially inner surface of the magnetic flux guide member 38. Thus, the yoke 82 is disposed opposite both the end of the mover core 33 in the second direction AD2 and the magnetic flux guide member 38.

[0050] As a result, the yoke 82 provides a path for the magnetic flux to travel from the lower end surface of the mover core 33, pass through the bottom wall of the sleeve 63, and reach the annular end surface of the cylindrical wall 84. Furthermore, the yoke 82 provides a path for the magnetic flux to travel from the radially outer surface of the mover core 33, pass through the radially outer wall of the sleeve 63, pass through the magnetic flux guide member 38, and reach the radially outer surface of the cylindrical wall 84.

[0051] 2 is an exploded perspective view showing the magnetic bias device 8. The permanent magnet 81 is a flat cylinder. The permanent magnet 81 is magnetized so that the north pole appears on the upper surface in the figure and the south pole appears on the lower surface in the figure.

[0052] The yoke 82 is a member with a U-shaped cross section. The yoke 82 can also be called a cup-shaped member. The yoke 82 has a bottom wall 83 and a cylindrical wall 84. The inner diameter of the cylindrical wall 84 is larger than the outer diameter of the permanent magnet 81. The bottom wall 83 and the cylindrical wall 84 are formed from a continuous material. The permanent magnet 81 is disposed in the internal space defined by the bottom wall 83 and the cylindrical wall 84. The yoke 82 is made of a magnetic material with soft magnetic properties. The yoke 82 is made of metal, for example, iron.

[0053] The upper surface of the permanent magnet 81 faces the mover core 33 via the sleeve 63. The lower surface of the permanent magnet 81 faces the bottom wall 83 of the yoke 82. The yoke 82 faces the magnetic flux guide member 38. This facing relationship is provided by a relationship that allows magnetic flux to pass through. This facing relationship can be provided by mechanical contact.

[0054] The magnetic bias device 8 is fixed to the electromagnetic unit 3. The magnetic bias device 8 is fixed to the electromagnetic unit 3 by a fixing member. The fixing member may be provided by a fastening member such as a bolt and / or a screw. Additionally or alternatively, the fixing member may be provided by a joining member such as an adhesive, a potting resin, and / or welding. For example, a configuration in which a screw formed on the radially outer surface of the yoke 82 is connected to a screw formed on the radially inner surface of the magnetic flux guide member 38 may be employed. In this case, the permanent magnet 81 may be sandwiched between the sleeve 63 and the yoke 82. Additionally or alternatively, adhesive may be applied between the permanent magnet 81 and the sleeve 63, between the permanent magnet 81 and the yoke 82, between the yoke 82 and the sleeve 63, and / or between the yoke 82 and the magnetic flux guide member 38. The magnetic bias device 8 is supported by the lower case 12 as a component belonging to the electromagnetic unit 3.

[0055] Alternatively to this embodiment, the magnetic bias device 8 may be attracted and fixed to the magnetic flux guide member 38 and / or the mover core 33 by the magnetic force of the permanent magnet 81. In this case as well, the magnetic bias device 8 is supported by the lower case 12 as a component belonging to the electromagnetic unit 3.

[0056] Returning to FIG. 1 , the permanent magnet 81 is disposed radially inward of the cylindrical shape of the electromagnetic coil 31. The permanent magnet 81 is disposed radially inward of the radially outer surface of the sleeve 63. Furthermore, the permanent magnet 81 is disposed radially inward of the radially outer surface of the mover core 33. As a result, the permanent magnet 81 is disposed opposite the end of the mover core 33 in the second direction AD2. As a result, the permanent magnet 81 applies an attractive force in the second direction AD2 to the mover core 33 via the bottom wall of the sleeve 63.

[0057] The yoke 82 is disposed radially inward of the cylindrical shape of the electromagnetic coil 31. The yoke 82 is disposed radially inward of the radially outer surface of the sleeve 63. As a result, the end face of the cylindrical wall 83 of the yoke 82 is disposed opposite the end of the mover core 33 in the second direction AD2, via the bottom wall of the sleeve 63. As a result, the yoke 82 applies an attractive force in the second direction AD2, which is caused by the magnetic force of the permanent magnet 81, to the mover core 33, via the bottom wall of the sleeve 63.

[0058] Therefore, both the permanent magnet 81 and the yoke 82 are disposed radially inside the electromagnetic coil 31. In addition, both the permanent magnet 81 and the yoke 82 are disposed opposite the ends of the mover core 33.

[0059] FIG. 3 is a partial cross-sectional view showing the magnetic flux in the OFF state. FIG. 3 shows the bias magnetic flux PM in the base position of the mover core 33. The bias magnetic flux PM is indicated by a dashed line. A power supply circuit that supplies current to the electromagnetic coil 31 is illustrated by a power supply 91 and a switch element 92. The switch element 92 may be a manually operated switch element or may be provided by an electronic control device including a microprocessor and a memory element. The switch element 92 is open. In this state, the electromagnetic coil 31 is not energized.

[0060] The bias magnetic flux PM flows through a magnetic circuit including the permanent magnet 81, the mover core 33, the magnetic flux guide member 38, and the yoke 82. The bias magnetic flux PM flows through the sleeve 63 between the permanent magnet 81 and the mover core 33. Furthermore, the bias magnetic flux PM flows through the sleeve 63 between the mover core 33 and the magnetic flux guide member 38. Furthermore, the bias magnetic flux PM flows through the sleeve 63 between the mover core 33 and the yoke 82. The bias magnetic flux PM generates a bias force that attracts the mover core 33 in the second direction AD2.

[0061] FIG. 4 is a partial cross-sectional view showing the magnetic flux in the ON state. FIG. 4 shows the bias magnetic flux PM when the mover core 33 is in the ON position (excited position). FIG. 4 also shows the electromagnetic magnetic flux EM when the electromagnetic coil 31 is in the ON state. The electromagnetic magnetic flux EM is indicated by a dashed line. The switch element 92 is closed. In this state, the electromagnetic coil 31 is energized.

[0062] The bias magnetic flux PM flows through a magnetic circuit including the permanent magnet 81, the mover core 33, the magnetic flux guide member 38, and the yoke 82. The bias magnetic flux PM flows through the sleeve 63 between the permanent magnet 81 and the mover core 33. Furthermore, the bias magnetic flux PM flows through the sleeve 63 between the mover core 33 and the magnetic flux guide member 38. The bias magnetic flux PM generates a bias force that attracts the mover core 33 in the second direction AD2.

[0063] When current is applied to the electromagnetic coil 31, electromagnetic magnetic flux EM is induced in the stator core 32, the mover core 33, and the yoke 34. The electromagnetic magnetic flux EM flows through a magnetic circuit including the mover core 33, the stator core 32, the plate member 36, the back yoke member 37, and the magnetic flux guide member 38. The electromagnetic magnetic flux EM flows through the sleeve 63 between the magnetic flux guide member 38 and the mover core 33. The electromagnetic magnetic flux EM causes normal electromagnetic behavior that attracts the mover core 33 in the first direction AD1.

[0064] The bias force generated by the bias magnetic flux PM and the normal driving force caused by the electromagnetic magnetic flux EM are in opposite directions. The bias magnetic flux PM and the electromagnetic magnetic flux EM are in opposite directions inside the magnetic flux guide member 38. The bias magnetic flux PM is the magnetic flux supplied by the permanent magnet 81. The electromagnetic magnetic flux EM is the magnetic flux supplied by the electromagnetic coil 31 in the ON state.

[0065] The electromagnetic flux EM is much larger than the bias flux PM and is strong enough to move the mover core 33 in the first direction AD1 against the bias spring 35 and the magnetic bias device 8.

[0066] On the other hand, the bias magnetic flux PM holds the mover core 33 in the base position in the OFF state. The magnetic bias device 8 applies the strongest attractive force to the mover core 33 when the mover core 33 is in the base position. When the mover core 33 moves in the first direction AD1 from the base position, the magnetic bias device 8 loses the attractive force in the second direction AD2 as the moving distance from the base position increases. At this time, the electromagnetic magnetic flux EM of the electromagnetic coil 31 causes the mover core 33 to move in the first direction AD1. The behavior of the mover core 33 due to the electromagnetic magnetic flux EM is normal. The magnetic bias device 8 does not significantly interfere with the normal behavior of the mover core 33. Therefore, the magnetic bias device 8 strongly holds the mover core 33 in the base position in the OFF state and allows the mover core 33 to behave normally in the ON state.

[0067] The mover core 33 may exhibit undesired behavior in the OFF state. For example, in the OFF state, the mover core 33 may move in the first direction AD1 against the bias spring 35 due to strong vibration. In this case, the electromagnetic unit 3 may malfunction. The contact unit 2 may also malfunction.

[0068] In this embodiment, in the off state, the magnetic bias device 8 applies a bias force to the mover core 33. Therefore, in this embodiment, malfunction of the electromagnetic part 3 and the contact part 2 is suppressed in the off state. Specifically, vibration resistance performance that prevents malfunction due to vibration is improved. Therefore, according to this embodiment, erroneous on-state behavior in the off state is suppressed.

[0069] Second Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a cylindrical permanent magnet 81 and a cup-shaped yoke 82. Instead, in this embodiment, the permanent magnet 281 is a cylindrical member. In this embodiment, the yoke 82 is provided by combining multiple members.

[0070] 5, the magnetic bias device 8 includes a permanent magnet 281 and a yoke 82. The permanent magnet 281 is a cylindrical member. The yoke 82 is provided by combining a plurality of members.

[0071] 6 , the permanent magnet 281 is a cylindrical member. The permanent magnet 281 has a hollow portion in the center. The cylindrical permanent magnet 281 reduces the volume of the permanent magnet. As a result, the cylindrical permanent magnet 281 contributes to reducing the weight of the electromagnetic unit 3. From another perspective, the cylindrical permanent magnet 281 enables cost reduction of the electromagnetic unit 3.

[0072] In FIG. 6 , the yoke 82 has a plate-shaped bottom wall 283. The yoke 82 has a cylindrical wall 284. The bottom wall 283 and the cylindrical wall 284 are separate members with no continuous material. The bottom wall 283 and the cylindrical wall 284 can be joined together and handled as a single member. The bottom wall 283 and the cylindrical wall 284 are fixed together to allow magnetic flux to pass through. In this embodiment, the yoke 82 also provides an additional magnetic circuit for the permanent magnet 281.

[0073] According to this embodiment, the same effects as those of the preceding embodiment can be obtained. Furthermore, according to this embodiment, the volume of the permanent magnet 281 can be reduced compared to the volume of the permanent magnet 81 of the preceding embodiment.

[0074] Third Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the yoke 82 has a cylindrical wall 84, 284. Instead, in this embodiment, the yoke 82 has only a plate-shaped bottom wall 383.

[0075] 7 , the yoke 82 has a plate-shaped bottom wall 383. The yoke 82 does not have a cylindrical wall. The bottom wall 383 is disposed so that a central region of the bottom wall 383 faces the lower surface of the permanent magnet 81. The bottom wall 383 is disposed so that a radially outer edge portion of the bottom wall 383 faces the back yoke member 37 and the magnetic flux guide member 38.

[0076] In this embodiment, only the permanent magnet 81 faces the mover core 33. The permanent magnet 81 and the mover core 33 face each other in the axial direction. In this embodiment, the bottom wall 383 serving as the yoke 82 does not face the axial end of the mover core 33.

[0077] As a result, the magnetic flux of the permanent magnet 81 passes through the permanent magnet 81, the mover core 33, the magnetic flux guide member 38, the back yoke member 37, and the bottom wall 383. The magnetic flux of the permanent magnet 81 passes through the sleeve 63 between the permanent magnet 81 and the mover core 33. The magnetic flux of the permanent magnet 81 passes through the sleeve 63 between the mover core 33 and the magnetic flux guide member 38.

[0078] According to this embodiment, the same effects as those of the preceding embodiment can be obtained. Furthermore, according to this embodiment, the yoke 82 can be made in a simple shape.

[0079] Fourth Embodiment This embodiment is a modification based on the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a yoke 82. Instead, in this embodiment, the magnetic bias device 8 includes only a permanent magnet 481.

[0080] 8, the magnetic bias device 8 includes a permanent magnet 481. The permanent magnet 481 is cylindrical. The permanent magnet 481 is magnetized in the axial direction. In this embodiment, only the permanent magnet 481 faces the mover core 33. The permanent magnet 481 faces the mover core 33 at the upper surface of the permanent magnet 481 in the drawing. The lower surface of the permanent magnet 481 in the drawing is magnetically coupled to the magnetic flux guide member 38 and the back yoke member 37 via the lower case 12 and a space.

[0081] As a result, the magnetic flux of the permanent magnet 481 passes through the permanent magnet 481, the mover core 33, and the magnetic flux guide member 38. A portion of the magnetic flux of the permanent magnet 481 passes through the permanent magnet 481, the mover core 33, the magnetic flux guide member 38, and the back yoke member 37. The magnetic flux of the permanent magnet 81 passes through the sleeve 63 between the permanent magnet 481 and the mover core 33. The magnetic flux of the permanent magnet 81 passes through the sleeve 63 between the mover core 33 and the magnetic flux guide member 38.

[0082] According to this embodiment, the same effects as those of the preceding embodiment can be obtained. Furthermore, according to this embodiment, a simple magnetic bias device 8 that only includes a permanent magnet 481 can be employed.

[0083] The first to fourth embodiments have the following configurations. The back yoke member 37 has side walls extending axially from the ends of the plate member 36, and a bottom wall that magnetically connects the side walls to the magnetic flux guide member 38. The side walls can be provided as flat or cylindrical walls. The bottom wall can be provided as a flat or disk-shaped wall. The back yoke member 37 in this embodiment is provided as a plate-shaped member that can be called U-shaped or bracket-shaped.

[0084] The back yoke member 37 has two L-shaped walls on both the left and right sides of the magnetic flux guide member 38. The L-shaped walls include a bottom wall and a side wall. The plate member 36 and the back yoke member 37 provide a path for the magnetic flux induced by the electromagnetic coil 31. The plate member 36 and the back yoke member 37 provide two L-shaped members on both the left and right sides of the stator core 32 and the mover core 33. These two L-shaped members magnetically connect the stator core 32 and the magnetic flux guide member 38. Alternatively, the plate member 36 and the back yoke member 37 may be provided by a single C-shaped member. In this case, the single C-shaped member magnetically connects the stator core 32 and the magnetic flux guide member 38.

[0085] The position of the mover core 33 in FIG. 4 is also referred to as the on position, the activated position, or the excited position. When the mover core 33 is in the activated position, the magnetic gap between the stator core 32 and the mover core 33 is small. When the mover core 33 is in the activated position, the magnetic gap between the magnetic bias device 8 and the mover core 33 is large. Due to the magnetic gap between the magnetic bias device 8 and the mover core 33, the bias magnetic flux PM is small. Therefore, the force with which the magnetic bias device 8 attracts the mover core 33 in the second direction AD2 is the weakest within the operating range of the mover core 33.

[0086] Fifth Embodiment This embodiment is a modification based on the preceding embodiment. In the above-described embodiment, the magnetic bias device 8 is disposed facing the end of the mover core 33 in the second direction so as to be located within the axial projection range of the mover core 33. Instead, in this embodiment, the magnetic bias device 8 is disposed mainly radially outward of the mover core 33. The magnetic bias device 8 is disposed so that only the yoke portion as the magnetic pole of the magnetic bias device 8 faces the end of the mover core 33 in the axial direction.

[0087] 9 , the electromagnetic section 3 includes a main electromagnetic coil 31 and an additional electromagnetic coil 539. The electromagnetic coil 31 is disposed between the contact portion 2 and the additional electromagnetic coil 539. In other words, the contact portion 2 is disposed at one axial end of the electromagnetic coil 31. The additional electromagnetic coil 539 is disposed at the other axial end of the electromagnetic coil 31, i.e., the end opposite the contact portion 2. The additional electromagnetic coil 539 has a bobbin 539 a and a coil 539 b. The additional electromagnetic coil 539 is disposed radially outside the mover core 33. The additional electromagnetic coil 539 does not face the end face of the mover core 33 in the axial direction of the mover core 33. From another perspective, the additional electromagnetic coil 539 is disposed radially outside the sleeve 63. The additional electromagnetic coil 539 does not face the end face of the sleeve 63 in the axial direction of the sleeve 63. The electromagnetic coil 31 and the additional electromagnetic coil 539 are disposed in a layered manner in the axial direction. Between the electromagnetic coil 31 and the additional electromagnetic coil 539, an intermediate wall 537c, which will be described later, is disposed.

[0088] The back yoke member 37 includes a side wall 537a and a bottom wall 537b. The back yoke member 37 further includes an intermediate wall 537c. In the illustrated example, two sets of magnetic paths including the side wall 537a, the bottom wall 537b, and the intermediate wall 537c are arranged on both the left and right sides of the electromagnetic main part. The electromagnetic main part includes the stator core 32, the mover core 33, and the magnetic flux guide member 38. An end of the bottom wall 537b faces an end face of the mover core 33 in the axial direction of the mover core 33.

[0089] The intermediate wall 537c is disposed to extend radially between the inner surface of the side wall 537a and the end of the magnetic flux guide member 38. The intermediate wall 537c is disposed between the electromagnetic coil 31 and the additional electromagnetic coil 539. The intermediate wall 537c magnetically couples the side wall 537a and the magnetic flux guide member 38. The intermediate wall 537c provides a common magnetic path through which the magnetic flux induced by the electromagnetic coil 31, the magnetic flux induced by the additional electromagnetic coil 539, and the magnetic flux supplied by a permanent magnet 581 (described later) pass. From this perspective, the intermediate wall 537c is also referred to as a common magnetic path member.

[0090] The intermediate wall 537c is a member that functions as a magnetic path for the magnetic flux induced in the main electromagnetic coil 31. Moreover, the intermediate wall 537c is also a member that functions as a magnetic path for the magnetic flux induced in the additional electromagnetic coil 539. As a result, the electromagnetic coil 31 supplies magnetic flux to the mover core 33 via the stator core 32, the plate member 36, the side wall 537a, the intermediate wall 537c, and the magnetic flux guide member 38. When excited, the electromagnetic coil 31 supplies magnetic flux that moves the mover core 33 in the first direction AD1.

[0091] Furthermore, the electromagnetic unit 3 includes an additional electromagnetic coil 539. The additional electromagnetic coil 539 functions as a controllable electromagnet that can be switched between an on state and an off state of an excitation current. The additional electromagnetic coil 539 supplies the mover core 33 with magnetic flux in the opposite direction to the magnetic flux supplied to the mover core 33 by the magnetic bias device 8, which will be described later. The magnetic bias device 8 supplies the mover core 33 with magnetic flux that attracts the mover core 33 in the second direction AD2. Therefore, when excited, the additional electromagnetic coil 539 supplies magnetic flux that at least partially cancels the magnetic flux supplied by the magnetic bias device 8. Moreover, the magnetic flux supplied by the additional electromagnetic coil 539 can be electromagnetically turned on and off, so the effect of canceling the magnetic flux supplied by the magnetic bias device 8 can be turned on and off.

[0092] 9, the additional electromagnetic coil 539 provides an element independent of the electromagnetic coil 31. In FIG. 10, a control device 93 including a plurality of switch elements 92 can independently control the on / off state of the electromagnetic coil 31 and the on / off state of the additional electromagnetic coil 539. The additional electromagnetic coil 539 is electrically independent from the electromagnetic coil 31. The on / off state of the additional electromagnetic coil 539 can be switched independently of the on / off state of the electromagnetic coil 31, even if it is synchronized with the on / off state of the electromagnetic coil 31.

[0093] The controller 93 includes circuitry providing at least one processor. The processor may be provided in whole or in part by the circuitry providing the control. The processor may be provided at least in part by executing a program stored in a memory device. In either case, the controller 93 includes at least one processor circuit configured by the circuitry and / or the program to implement the control methods described herein.

[0094] 9 , the electromagnetic unit 3 includes a magnetic bias device 8. The magnetic bias device 8 includes a permanent magnet 581. The permanent magnet 581 is disposed in a magnetic path through which the magnetic flux induced by the additional electromagnetic coil 539 passes. The permanent magnet 581 is disposed at a connecting portion between the side wall 537 a and the intermediate wall 537 c. In this embodiment, a member (yoke) that guides the magnetic flux of the permanent magnet 581 to the mover core 33 and the magnetic flux guide member 38 is provided by the bottom wall 537 b, the intermediate wall 537 c, and the lower member 537 d of the side wall 537 a.

[0095] The permanent magnet 581 is magnetized in the left-right direction as shown in the figure. The permanent magnet 581 is a magnetic force source that applies a magnetic bias force to the mover core 33. The permanent magnet 581 supplies a magnetic flux that attracts the mover core 33 in a direction that pulls the mover core 33 away from the stator core 32, i.e., in the second direction AD2. The magnetization direction of the permanent magnet 581 is a direction that supplies a magnetic flux in the opposite direction to the magnetic flux induced in the additional electromagnetic coil 539. Therefore, when the additional electromagnetic coil 539 is excited, the magnetic flux supplied by the permanent magnet 581 is canceled.

[0096] The permanent magnet 581 has a shape that can be called a rod or a plate. The permanent magnet 581 includes a permanent magnet 581a arranged on one side in the radial direction of the mover core 33. The permanent magnet 581 includes a permanent magnet 581b arranged on the other side in the radial direction of the mover core 33. Alternatively, the permanent magnet 581 may include only one of the permanent magnet 581a and the permanent magnet 581b.

[0097] In FIG. 11 , the magnetic flux in multiple current-carrying modes is illustrated by dashed lines and arrows. In FIG. 11 , "MODE 1" indicates a state in which the mover core 33 is located at the base position (off state). At this time, the electromagnetic coil 31 is in a non-excited state (off state). The additional electromagnetic coil 539 is also in a non-excited state (off state). The permanent magnet 581 supplies magnetic flux via the intermediate wall 537c, the magnetic flux guide member 38, the mover core 33, the bottom wall 537b, and a portion of the side wall 537a. The portion of the side wall 537a is only the lower member 537d of the side wall 537a in the illustration. The portion of the side wall 537a is the portion between one end of the bottom wall 537b and one end of the permanent magnet 581. In other words, a portion of the side wall 537a is a lower member 537d between one end of the bottom wall 537b and the connecting portion between the side wall 537a and the intermediate wall 537c. The intermediate wall 537c, the magnetic flux guide member 38, the bottom wall 537b, and a portion of the side wall 537a provide a magnetic path through which the bias magnetic flux PM that attracts the mover core 33 in the second direction AD2 is supplied from the permanent magnet 581.

[0098] The permanent magnet 581 continues to supply the bias magnetic flux PM. The permanent magnet 581 continues to attract the mover core 33 to the base position. Therefore, the mover core 33 is biased toward the base position by the magnetic force of the permanent magnet 581 in addition to the biasing force of the bias spring 35. This suppresses erroneous behavior of the electromagnet device and the electromagnetic relay in the off state.

[0099] In FIG. 11 , "MODE 2" indicates a state in which both the electromagnetic coil 31 and the additional electromagnetic coil 539 are excited. When the electromagnetic coil 31 is excited, it supplies a magnetic flux EMM to the mover core 33, attracting the mover core 33 in the first direction AD1. The direction of the magnetic flux EMM when the electromagnetic coil 31 is excited is determined by the winding direction of the coil 31b. In the figure, the current direction of the coil 31b is indicated by an arrow symbol. The force with which the permanent magnet 581 urges the mover core 33 in the second direction AD2 toward the base position is clearly smaller than the force with which the excited electromagnetic coil 31 attracts the mover core 33 in the first direction AD1. Therefore, when the electromagnetic coil 31 is excited, the mover core 33 is attracted in the first direction AD1 against both the bias spring 35 and the permanent magnet 581.

[0100] Furthermore, when the additional electromagnetic coil 539 is excited, it supplies a magnetic flux EMC in a direction that cancels the magnetic flux supplied by the permanent magnet 581. The direction of the magnetic flux EMC when the additional electromagnetic coil 539 is excited is determined by the winding direction of the coil 539b. The number of turns of the coil 539b is clearly smaller than the number of turns of the coil 31b. The magnetic flux EMC required for the additional electromagnetic coil 539 is only sufficient to cancel the bias magnetic flux PM of the permanent magnet 581. Therefore, when the electromagnetic coil 31 remains de-energized and only the additional electromagnetic coil 539 is energized, the mover core 33 remains in the base position without moving. However, when the additional electromagnetic coil 539 is energized, the magnetic flux EMC induced in the additional electromagnetic coil 539 cancels at least a portion of the bias magnetic flux PM of the permanent magnet 581. As a result, the force holding the mover core 33 in the base position is reduced. That is, when the additional electromagnetic coil 539 is in an excited state, the force holding the mover core 33 in the base position decreases.

[0101] In this embodiment, the additional electromagnetic coil 539 may be excited when the main electromagnetic coil 31 transitions from a non-excited state to an excited state. Alternatively, the additional electromagnetic coil 539 may be excited during a transition period including the instant of transition and before and / or after the instant of transition. In these cases, the transition of the electromagnetic coil 31 from a non-excited state to an excited state allows the mover core 33 to move in the first direction AD1 reliably and with high responsiveness.

[0102] As the mover core 33 moves from the base position toward the activated position, the magnetic gaps formed on both sides of the mover core 33 in the axial direction change. As the mover core 33 moves from the base position to the activated position, the magnetic gap between the mover core 33 and the bottom wall 537b increases, and conversely, the magnetic gap between the mover core 33 and the stator core 32 decreases. Eventually, the magnetic gap between the mover core 33 and the bottom wall 537b becomes larger than the magnetic gap between the mover core 33 and the stator core 32. In response to these changes in the magnetic gap, the path of the bias magnetic flux PM supplied by the permanent magnet 581 changes.

[0103] When the mover core 33 is in the base position, the bias magnetic flux PM passes through the magnetic gap between the mover core 33 and the bottom wall 537b. In contrast, after the mover core 33 is attracted to the stator core 32, the bias magnetic flux PM passes through the magnetic gap between the mover core 33 and the stator core 32. In this state, the bias magnetic flux PM biases the mover core 33 in the first direction AD1. In particular, at the end of the movement of the mover core 33, the magnetic gap between the mover core 33 and the stator core 32 becomes approximately zero (0).

[0104] In FIG. 11 , "MODE 3" indicates a state after the mover core 33 is attracted. In "MODE 3," the mover core 33 is held in the activated position in the first direction AD1. In this state, the additional electromagnetic coil 539 is in a non-excited state. Only the electromagnetic coil 31 is in an excited state. In this state, the bias magnetic flux PM of the permanent magnet 581 flows through the intermediate wall 537c, the magnetic flux guide member 38, the mover core 33, the stator core 32, the plate member 36, and the side wall 537a. Furthermore, the direction of the bias magnetic flux PM is the same as the direction of the magnetic flux EMM induced in the electromagnetic coil 31. Therefore, both the bias magnetic flux PM supplied by the permanent magnet 581 and the magnetic flux EMM induced in the electromagnetic coil 31 contribute to holding the mover core 33 in the activated position.

[0105] In this embodiment, the permanent magnet 581 of the magnetic bias device 8 is disposed in a magnetic path (intermediate wall 537c) common to the electromagnetic coil 31 and the additional electromagnetic coil 539. The magnetization direction of the permanent magnet 581 is the same as the direction of the magnetic flux induced in the electromagnetic coil 31. The magnetization direction of the permanent magnet 581 is opposite to the direction of the magnetic flux induced in the additional electromagnetic coil 539. This allows the path of the magnetic flux supplied by the permanent magnet 581 to be switched between when the mover core 33 is in the base position ("MODE 1") and when the mover core 33 is in the activated position ("MODE 3"). When the mover core 33 is in the base position ("MODE 1"), the permanent magnet 581 contributes to maintaining the mover core 33 in the base position. In "MODE 1", the permanent magnet 581 functions to assist the bias spring 35. On the other hand, when the mover core 33 is in the activated position ("MODE 3"), the permanent magnet 581 holds the mover core 33 in the activated position. That is, in "MODE 3," the permanent magnet 581 functions to counter the bias spring 35. In "MODE 3," the force with which the permanent magnet 581 attracts the mover core 33 in the first direction AD1 is smaller than the force with which the bias spring 35 pushes the mover core 33 in the second direction AD2. Therefore, when the electromagnetic coil 31 transitions from an excited state to a de-excited state, the bias spring 35 moves the mover core 33 in the second direction AD2 against the permanent magnet 581. In "MODE 3," the permanent magnet 581 functions to assist the excited electromagnetic coil 31.

[0106] 12 , the control device 93 executes a control process 500. The control process 500 switches the electromagnetic relay 1 between an OFF state and an ON state by controlling the electromagnetic coil 31. The control process 500 drives the electromagnetic relay 1 to an OFF state by controlling the electromagnetic coil 31 to a non-excited state. The control process 500 drives the electromagnetic relay 1 to an ON state by controlling the electromagnetic coil 31 to an excited state. The control process 500 controls the additional electromagnetic coil 539 to an excited state when the electromagnetic coil 31 transitions from a non-excited state to an excited state.

[0107] Here, the transition period includes the moment of transition from the de-excited state to the excited state, a short period before the transition period, and / or a short period after the transition period. In this embodiment, during the transition period, including the moment of transition of the electromagnetic coil 31 from the de-excited state to the excited state and the short period after the transition period, the additional electromagnetic coil 539 is controlled to be in the excited state for only a predetermined limited period. This allows the bias magnetic flux PM by the permanent magnet 581 to be canceled. Alternatively, the transition period may include a short period before the transition period. The short period may be a short period during which the constraint of the mover core 33 by the permanent magnet 581 is released from the constrained state to the unconstrained state, or a short period of time. The short period may be, for example, a predetermined time. Alternatively, the short period may be a period until movement of the mover core 33 is observed. Therefore, the control process 500 controls the additional electromagnetic coil 539 from the excited state (ON state) to the de-excited state (OFF state) while maintaining the electromagnetic coil 31 in the excited state (ON state).

[0108] The control process 500 includes step 501. In step 501, an ON / OFF command for the electromagnetic relay 1 is input. For example, the ON / OFF command for the electromagnetic relay 1 is given from a control device of a system that uses the electromagnetic relay 1. The control process 500 includes step 502. In step 502, the type of command is determined. In step 502, it is determined whether the command is OFF, a transition from OFF to ON, or ON. If the command is OFF, the process branches to OFF and proceeds to step 503. If the command is a transition from OFF to ON, the process branches to OFF->ON and proceeds to step 505. If the command is ON, the process branches to ON and proceeds to step 509.

[0109] In step 503, coil 31b is controlled to be in the OFF state, thereby controlling electromagnetic coil 31 to be in the non-excited state. In step 504, coil 539b is controlled to be in the OFF state, thereby controlling additional electromagnetic coil 539 to be in the non-excited state. Steps 503 and 504 control electromagnetic relay 1 to be in the OFF state. After this, the process returns to step 501.

[0110] In step 505, coil 31b is controlled to be in the ON state, thereby controlling electromagnetic coil 31 to be in the excited state. In step 506, coil 539b is controlled to be in the ON state, thereby controlling additional electromagnetic coil 539 to be in the excited state. Steps 505 and 506 control electromagnetic relay 1 to be in the ON state. If steps 503 and 504 were executed in the immediately preceding processing and steps 505 and 506 are executed in the current processing, electromagnetic relay 1 transitions from the OFF state to the ON state.

[0111] In step 507, it is determined whether a predetermined condition indicating the completion of the transition is met. If the condition is not met, the process branches to NO and repeats step 507. If the condition is met, the process branches to YES and proceeds to step 508. The condition may be, for example, a predetermined time. Alternatively, the condition may be whether movement of the mover core 33 from the base position is observed. In step 508, the additional electromagnetic coil 539 is controlled to a de-energized state by controlling the coil 539b to an off state. Therefore, the additional electromagnetic coil 539 is controlled from an energized state to a de-energized state while the electromagnetic coil 31 is maintained in an energized state. After step 508, the process returns to step 501.

[0112] By executing steps 505-508, the electromagnetic relay 1 transitions from the OFF state to the ON state. By executing steps 507 and 508, the power consumption for turning on the coil 539b is limited.

[0113] In step 509, coil 31b is controlled to be in the ON state, thereby controlling electromagnetic coil 31 to be in the excited state. In step 510, coil 539b is controlled to be in the OFF state, thereby controlling additional electromagnetic coil 539 to be in the non-excited state. Steps 509 and 510 cause electromagnetic relay 1 to be continuously controlled to be in the OFF state. After this, the process returns to step 501.

[0114] In Figure 13, waveform (1) represents an on / off command for electromagnetic relay 1. Waveform (31b) represents the energized state (on or off) of coil 31b. Waveform (539b) represents the energized state (on or off) of coil 539b. The horizontal axis represents time. At time t1, electromagnetic relay 1 transitions from the off state to the on state. After a predetermined period has elapsed since time t1, when time t2 is reached, it is determined whether the condition in step 507 is met. At time t2, coil 539b is controlled to the off state. After time t2, electromagnetic relay 1 is maintained in the on state. Eventually, when time t3 is reached, electromagnetic relay 1 transitions from the on state to the off state at time t3.

[0115] This embodiment achieves the same first effect as the preceding embodiment. That is, the permanent magnet 581 of the magnetic bias device 8 holds the mover core 33 in the base position. Therefore, erroneous behavior of the electromagnetic relay 1 in the off state is suppressed.

[0116] Furthermore, this embodiment provides a second effect. The electromagnetic relay 1 includes the additional electromagnetic coil 539 for canceling the magnetic flux of the permanent magnet 581. Therefore, by controlling the additional electromagnetic coil 539 to an excited state, it is possible to weaken the constraint of the mover core 33 by the permanent magnet 581. The electromagnet system includes a control device that controls the additional electromagnetic coil 539 to an excited state when the electromagnetic relay 1 transitions from an off state to an on state. This allows the electromagnet system to disable the magnetic bias device 8. As a result, the electromagnet system can achieve high responsiveness when transitioning from an off state to an on state.

[0117] Furthermore, this embodiment provides an additional third effect. The permanent magnet 581 is provided on the intermediate wall 537c, which is a common magnetic path member. As a result, when the mover core 33 is in the activated position, the magnetic flux supplied by the permanent magnet 581 contributes to holding the mover core 33 in the activated position.

[0118] Sixth Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a permanent magnet 581. In addition to this, in this embodiment, the magnetic bias device 8 includes a permanent magnet 681. The magnetic bias device 8 can include permanent magnets at various positions that can supply a magnetic flux that holds the mover core 33 in the base position.

[0119] 14, the bottom wall 537b includes a permanent magnet 681. The permanent magnet 681 includes a permanent magnet 681a arranged on one side in the radial direction of the mover core 33 and a permanent magnet 681b arranged on the other side in the radial direction of the mover core 33. The permanent magnet 681 is not provided in a common magnetic path member.

[0120] When the electromagnetic coil 31 is excited, the mover core 33 moves in the first direction AD1 from the base position toward the activated position. This movement gradually widens the magnetic gap between the mover core 33 and the bottom wall 537b. As a result, the magnetic flux of the permanent magnet 681 supplied to the mover core 33 gradually decreases. Therefore, when the mover core 33 is in the activated position, the magnetic flux of the permanent magnet 681 acting on the mover core 33 is small. In this embodiment, when the mover core 33 is in the base position, both the permanent magnet 581 and the permanent magnet 681 contribute to maintaining the base position. When the mover core 33 is in the activated position, the permanent magnet 581 contributes to maintaining the activated position. In contrast, the permanent magnet 681 makes almost no contribution to maintaining the activated position. Therefore, the permanent magnet 681 does not contribute to the third effect. In this embodiment, the permanent magnet 581 can achieve the same effects as the preceding embodiment.

[0121] Seventh Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a permanent magnet 581. Instead, in this embodiment, as shown in FIG. 15, the magnetic bias device 8 includes only a permanent magnet 781. The permanent magnet 781 is the same as the permanent magnet 681. This embodiment can achieve the first and second effects.

[0122] Eighth Embodiment This embodiment is a modification based on the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a permanent magnet 781. In addition, in this embodiment, the magnetic bias device 8 includes a permanent magnet 881.

[0123] 16 , the plate member 36 includes a permanent magnet 881. The permanent magnet 881 includes a permanent magnet 881a arranged on one radial side of the mover core 33 and a permanent magnet 881b arranged on the other radial side of the mover core 33. The permanent magnet 881 is not provided on a common magnetic path member. When the mover core 33 is in the base position, the permanent magnet 781 contributes to maintaining the base position. In contrast, the permanent magnet 881 makes almost no contribution to maintaining the base position. When the mover core 33 is in the activated position, the permanent magnet 881 contributes to maintaining the activated position. In contrast, the permanent magnet 681 makes almost no contribution to maintaining the activated position. According to this embodiment, the first and second operational effects can be obtained.

[0124] Ninth Embodiment This embodiment is a modification of the preceding embodiment as a basic form. In the above embodiment, the magnetic bias device 8 includes a permanent magnet 981. In addition, in this embodiment, as shown in FIG. 17 , the magnetic bias device 8 includes a permanent magnet A81. The permanent magnet A81 is provided on the upper member of the side wall 537a between the plate member 36 and the intermediate wall 537c. The permanent magnet A81 includes a permanent magnet A81a and a permanent magnet A81b. The permanent magnet A81 is not provided on the common magnetic path member. According to this embodiment, the first and second operational effects can be obtained.

[0125] Tenth Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a permanent magnet 981. In addition, in this embodiment, the magnetic bias device 8 includes a permanent magnet A81.

[0126] 18, the permanent magnet A81 is provided on the upper member of the side wall 537a between the plate member 36 and the intermediate wall 537c. The permanent magnet A81 includes a permanent magnet A81a and a permanent magnet A81b. The permanent magnet A81 is not provided on the common magnetic path member.

[0127] When the mover core 33 is in the base position, the permanent magnet 981 contributes to maintaining the base position. In contrast, the permanent magnet A81 makes almost no contribution to maintaining the base position. When the mover core 33 is in the activated position, the permanent magnet A81 contributes to maintaining the activated position. In contrast, the permanent magnet 981 makes almost no contribution to maintaining the activated position. According to this embodiment, the first and second operational effects can be obtained.

[0128] Eleventh Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the magnetic bias device 8 includes a permanent magnet 981. Instead, in this embodiment, the magnetic bias device 8 includes a permanent magnet B81.

[0129] 19 , the permanent magnet B81 is arranged so that at least a portion of the permanent magnet B81 is positioned within the projection range of the mover core 33 in the axial direction of the mover core 33. In other words, the permanent magnet B81 of the magnetic bias device 8 is arranged facing the end of the mover core 33 in the second direction AD2. The permanent magnet B81 is a flat member having an annular shape. The permanent magnet A81 is not provided in a common magnetic path member. According to this embodiment, the first and second operational effects can be obtained.

[0130] Other Embodiments The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and variations thereon by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0131] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0132] In the above embodiment, the magnetic bias device 8 has a cylindrical permanent magnet 81 or a cylindrical permanent magnet 281. Alternatively, the magnetic bias device 8 can be provided with permanent magnets of various shapes, such as a flat rectangular parallelepiped permanent magnet, a square cylindrical permanent magnet, or an assembly of multiple permanent magnets.

[0133] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0134] (Technical Idea 1) An electromagnet device comprising: an electromagnetic coil (31) that can be switched between an on state of an excitation current and an off state of an excitation current; a fixed magnetic body (32) that is disposed in a magnetic field induced by the electromagnetic coil and is fixedly disposed; a movable magnetic body (33) that is disposed in the magnetic field induced by the electromagnetic coil and is movable in a first direction (AD1) approaching the fixed magnetic body and in a second direction (AD2) opposite to the first direction, and that is at a base position in the second direction when the excitation current is off and moves from the base position towards the first direction when the excitation current is on; and a magnetic bias device (8) that supplies a magnetic flux that attracts the movable magnetic body in the second direction.

[0135] (Technical Concept 2) The electromagnet device according to Technical Concept 1, further comprising a bias spring (35) that applies a bias force that urges the movable magnetic body in the second direction.

[0136] (Technical Concept 3) The electromagnetic device according to Technical Concept 1 or 2, wherein the magnetic bias device includes a permanent magnet (81, 281, 481, 581, 681, 781, 881, 981, A81, B81) that applies the magnetic flux.

[0137] (Technical Concept 4) The electromagnet device according to Technical Concept 3, wherein the permanent magnet is disposed radially inside the electromagnetic coil.

[0138] (Technical Concept 5) The electromagnet device according to Technical Concept 3 or 4, wherein the magnetic bias device further includes a yoke (82, 537b, 537c, 537d) that guides the magnetic flux of the permanent magnet.

[0139] (Technical Idea 6) The electromagnet device according to Technical Idea 5, wherein both the permanent magnet and the yoke are disposed radially inside the electromagnetic coil and facing the end of the movable magnetic body.

[0140] (Technical Idea 7) The electromagnet device according to any one of Technical Ideas 1 to 6, further comprising a cylindrical magnetic flux guide member (38) arranged radially outside the movable magnetic body along the movement direction of the movable magnetic body.

[0141] (Technical Concept 8) The electromagnet device according to Technical Concept 7, wherein the magnetic flux supplied by the magnetic bias device and the magnetic flux supplied by the electromagnetic coil in the on state are in opposite directions in the magnetic flux guide member.

[0142] (Technical Idea 9) The electromagnet device according to Technical Idea 7 or 8, wherein the magnetic bias device is disposed facing both the end of the movable magnetic body and the magnetic flux guide member.

[0143] (Technical Idea 10) The electromagnet device according to any one of Technical Ideas 1 to 9, wherein the magnetic bias device is disposed opposite an end of the movable magnetic body in the second direction.

[0144] (Technical Idea 11) The electromagnet device according to any one of Technical Ideas 1 to 10 further includes an additional electromagnetic coil (539) that is independent of the electromagnetic coil (31), is switched between an on state of an excitation current and an off state of an excitation current, and supplies a magnetic flux to the movable magnetic body in the opposite direction to the magnetic flux supplied to the movable magnetic body by the magnetic bias device.

[0145] (Technical Idea 12) The electromagnet device according to Technical Idea 11 further comprises a common magnetic path member (537c) that provides a common magnetic path for the magnetic flux induced in the electromagnetic coil (31) and the magnetic flux induced in the additional electromagnetic coil (539), wherein the magnetic bias device is disposed on the common magnetic path member, and the magnetic flux supplied by the magnetic bias device acts on the movable magnetic body so as to attract the movable magnetic body in the second direction when the movable magnetic body is in the base position, and acts on the movable magnetic body so as to attract the movable magnetic body in the first direction when the movable magnetic body is in an activated position opposite to the base position.

[0146] (Technical Idea 13) An electromagnet system comprising: an electromagnet device according to Technical Idea 11 or Technical Idea 12; and a control device that controls the on / off of the electromagnetic coil and the on / off of the additional electromagnetic coil, wherein the control device has a processor circuit, and the processor circuit is configured to control the additional electromagnetic coil from the off state to the on state when the electromagnetic coil is transitioned from the off state to the on state.

[0147] (Technical Concept 14) The electromagnet system according to Technical Concept 13, wherein the processor circuit is configured to control the additional electromagnetic coil from the on state to the off state while maintaining the electromagnetic coil in the on state.

[0148] (Technical Idea 15) An electromagnetic relay comprising: an electromagnet device (3) according to any one of Technical Ideas 1 to 12; and a contact portion (2) that can be switched between an ON state and an OFF state by movement of the movable magnetic body.

Claims

1. An electromagnet device comprising: an electromagnetic coil (31) that can be switched between an on state and an off state of an excitation current; a fixed magnetic body (32) that is disposed in a magnetic field induced by the electromagnetic coil and is fixedly disposed; a movable magnetic body (33) that is disposed in the magnetic field induced by the electromagnetic coil and is movable in a first direction (AD1) approaching the fixed magnetic body and in a second direction (AD2) opposite to the first direction, and that is in a base position in the second direction when the excitation current is off and moves from the base position toward the first direction when the excitation current is on; and a magnetic bias device (8) that supplies a magnetic flux that attracts the movable magnetic body in the second direction.

2. The electromagnet device according to claim 1, further comprising a bias spring (35) for applying a bias force that urges the movable magnetic body in the second direction.

3. The electromagnetic device according to claim 1, wherein the magnetic bias device comprises a permanent magnet (81, 281, 481, 581, 681, 781, 881, 981, A81, B81) that applies the magnetic flux.

4. The electromagnetic device according to claim 3, wherein the permanent magnet is disposed radially inside the electromagnetic coil.

5. The electromagnet device according to claim 3, wherein the magnetic bias device further comprises a yoke (82, 537b, 537c, 537d) for guiding the magnetic flux of the permanent magnet.

6. An electromagnet device according to claim 5, wherein both the permanent magnet and the yoke are disposed radially inside the electromagnetic coil and opposed to the end of the movable magnetic body.

7. An electromagnet device according to any one of claims 1 to 6, further comprising a cylindrical magnetic flux guide member (38) arranged radially outside the movable magnetic body along the direction of movement of the movable magnetic body.

8. The electromagnet device according to claim 7, wherein the magnetic flux supplied by the magnetic bias device and the magnetic flux supplied by the electromagnetic coil in the on state are in opposite directions in the magnetic flux guide member.

9. The electromagnet device according to claim 7, wherein the magnetic bias device is disposed opposite both the end of the movable magnetic body and the magnetic flux guide member.

10. An electromagnet device according to claim 1, wherein the magnetic bias device is disposed opposite an end of the movable magnetic body in the second direction.

11. The electromagnet device according to claim 1, further comprising an additional electromagnetic coil (539) that is independent of the electromagnetic coil (31), is switched between an on state of an excitation current and an off state of an excitation current, and supplies a magnetic flux to the movable magnetic body in the opposite direction to the magnetic flux supplied to the movable magnetic body by the magnetic bias device.

12. An electromagnet device as described in claim 11, further comprising a common magnetic path member (537c) that provides a common magnetic path for the magnetic flux induced in the electromagnetic coil (31) and the magnetic flux induced in the additional electromagnetic coil (539), wherein the magnetic bias device is disposed on the common magnetic path member, and the magnetic flux supplied by the magnetic bias device acts on the movable magnetic body to attract it in the second direction when the movable magnetic body is in the base position, and acts on the movable magnetic body to attract it in the first direction when the movable magnetic body is in an activated position opposite to the base position.

13. An electromagnet system comprising: an electromagnet device according to claim 11; and a control device that controls the on / off of the electromagnetic coil and the on / off of the additional electromagnetic coil, wherein the control device has a processor circuit, and the processor circuit is configured to control the additional electromagnetic coil from the off state to the on state when the electromagnetic coil is transitioned from the off state to the on state.

14. The electromagnet system of claim 13, wherein the processor circuit is configured to control the additional electromagnetic coil from the on state to the off state while maintaining the electromagnetic coil in the on state.

15. An electromagnetic relay comprising the electromagnet device (3) according to claim 1 and a contact part (2) that can be switched between an ON state and an OFF state by the movement of the movable magnetic body.

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